Dissertations / Theses on the topic 'Actinobacteria'
To see the other types of publications on this topic, follow the link: Actinobacteria.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Actinobacteria.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
NERYS, Laís Ludmila de Albuquerque. "Avaliação das atividades antimicrobiana e anticâncer de metabólitos produzidos por Streptomyces sp UFPEDA 3407." Universidade Federal de Pernambuco, 2015. https://repositorio.ufpe.br/handle/123456789/18542.
Full textAbstract:
Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2017-04-10T19:33:04Z
No. of bitstreams: 2
license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5)
dissertação.pdf: 2311263 bytes, checksum: 2cd90cdab2e2c81506db007951c48578 (MD5)Made available in DSpace on 2017-04-10T19:33:04Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) dissertação.pdf: 2311263 bytes, checksum: 2cd90cdab2e2c81506db007951c48578 (MD5) Previous issue date: 2015-02-24
Actinobactérias são bactérias Gram-positivas que se destacam pela sua grande potencialidade de produzir diversos metabólitos secundários bioativos de interesse científico e industrial. Mais de 50% dos metabólitos microbianos bioativos descobertos são produzidos, tais como antimicrobianos e antitumorais, pelas actinobactérias principalmente pelo gênero Streptomyces.O câncer é considerado um importante problema de saúde pública em países desenvolvidos e em desenvolvimento, sendo a segunda causa de morte no Brasil e no mundo. Diante da diversidade de tecnologias e pesquisas aplicadas no campo das neoplasias, ainda não há uma terapia eficaz para o tratamento de todos os tipos de câncer e os quimioterápicos utilizados atualmente apresentam elevada toxicidade. Neste contexto, o presente projeto objetivou avaliar o potencial antimicrobiano e anticâncer dos extratos brutos produzidos pela por Streptomyces UFPEDA 3407. Após fermentação e extração dos metabólitos com diferentes solventes, foram realizados ensaios para avaliar a atividade antimicrobiana e citotóxica nas diferentes linhagens de células cancerígenas humanas (HL- 60, HT-29 e MCF- 7) e em eritrócitos murinos. Os resultados obtidos demonstraram que os extratos da biomassa extraídos com acetona, etanol e metanol apresentaram um bom espectro de ação contra bactérias Gram-positivas e leveduras. Nos ensaios de citotoxicidade, os mesmos extratos reduziram de maneira significativa a viabilidade das linhagens tumorais, mostrando resultados bastante promissores.
Actinomycetes are Gram-positive bacteria with high potential to produce various bioactive secondary metabolites of scientific and industrial interest. More than 50% of bioactive microbial metabolites discovered to date are produced by actinomycetes mainly by gender Streptomyces. Cancer is considered a major public health problem in developed and developing countries, and the second cause of death in Brazil and in the world. Given the diversity of technologies and applied research in the field of cancer, there is still no effective therapy for the treatment of all types of cancer and the chemotherapy drugs used today have high toxicity. In this context, this project aimed to evaluate the antimicrobial potential anticancer and crude extracts produced by Streptomyces actinobacteria UFPEDA 3407. After fermentation and extraction of metabolites with different solvents, tests were conducted to evaluate the antimicrobial and cytotoxic activity in different strains of human cancer cells (HL- 60, HT-29 and MCF-7) and murine erythrocytes. Partial results showed that the extracts of biomass extracted with acetone, ethanol and methanol had a good spectrum of action against Gram-positive bacteria and yeasts. In the cytotoxicity assays, the same extracts significantly reduced the viability of tumor cell lines, showing promising results.
2
Watson, Daniel John. "Screening of actinobacteria for novel antimalarial compounds." Doctoral thesis, Faculty of Health Sciences, 2021. http://hdl.handle.net/11427/33080.
Full textAbstract:
The success of our first-line antimalarial treatments is threatened by increased drug resistance in Plasmodium parasites. This makes the development of novel drugs critical to combat malaria. Historically, natural products have been an excellent source of novel antimalarial compounds and thus are an ideal place to search for potential drugs. Filamentous members of the bacterial phylum, Actinobacteria, are well-known antibiotic producers, but their antimalarial potential has not been well investigated. This makes these actinobacteria a potentially valuable source of novel antimalarial compounds. To evaluate the antimalarial potential of the filamentous actinobacteria, uncharacterized environmental actinobacterial strains from the Meyers laboratory culture collection, as well as the type strains of new actinobacterial species identified and characterized in the Meyers laboratory, were screened for antiplasmodial activity against drug-sensitive Plasmodium falciparum, NF54. Liquid cultures were extracted using the mid-polar solvent, ethyl acetate, with the aim of discovering drug-like molecules that can be administered orally. Thirty-one strains of actinobacteria belonging to eight genera (Actinomadura, Amycolatopsis, Gordonia, Kribbella, Micromonospora, Nocardia, Nonomuraea, and Streptomyces) were screened revealing fourteen active strains. Eight strains were identified for further study as the displayed antiplasmodial efficacy matching predefined criteria. Of these eight candidates, Streptomyces strain PR3 was selected, as it showed excellent antiplasmodial efficacy, no cytotoxicity against Chinese Hamster Ovary (CHO) or liver HepG2 cell lines, no haemotoxicity, and was easy to culture. Bioassay-guided fractionation of the crude extracts of strain PR3, supported by high-resolution mass spectrometry (HRMS) and nuclear magnetic resonance (NMR) analysis, was conducted to isolate and identify the compounds responsible for the antiplasmodial activity. During purification by solid phase extraction (SPE), a novel class of compounds was isolated. The structure of these compounds was elucidated by HRMS and NMR analysis and determined to be a series of crown ethers with a methylated backbone. These methylated crown ethers (MCE) were not produced by strain PR3, but by the cyclization of polypropylene glycol (PPG) oligomers from Amberlite® XAD-16N 20–60 mesh resin under aqueous conditions. The MCEs displayed weak antiplasmodial activity against P. falciparum NF54, without cytotoxicity against the Chinese Hamster Ovary, HepG2 cell lines, nor human erythrocytes. To the author's knowledge, the MCEs are novel compounds, and this is the first time the cyclization of PPG oligomers into crown ethers has been reported. As the MCEs were not responsible for strain PR3's potent antiplasmodial activity, further study was conducted. Using the Global Natural Product Social molecular networking (GNPS) workflow, genome mining, and NMR analysis, it was revealed that the cyclodepsipeptides, valinomycin, montanastatin, and nine other novel analogues were responsible for the high antiplasmodial activity detected. A review of the literature revealed that the structure of four of these analogues had been predicted, based on MS/MS and the biosynthesis of valinomycin. Using the same described biosynthetic logic and MS/MS analysis, two new cyclodepsipeptides, compounds 1054 and 1068, were elucidated. Unfortunately, chromatographic systems developed were unable to purify the cyclodepsipeptides, and individual evaluation of their antiplasmodial efficacy and host selectivity was not possible. The fraction containing the cyclodepsipeptides exhibited strong antiplasmodial activity against the drug-sensitive, NF54 and multidrug-resistant K1, strains of P. falciparum. No cytotoxicity was displayed against the CHO cell line and no haemotoxicity was seen against human erythrocytes. Moderate toxicity was exhibited against the liver HepG2 cell line; however, the selectivity index of the cyclodepsipeptides suggested that they are selectively targeting the Plasmodium parasites. Overall, these results are positive, and further study of the individual cyclodepsipeptides is warranted. During the investigation, discrepancies were noticed between different fractions in terms of antiplasmodial activity. These fractions contained both the MCEs and, cyclodepsipeptides along with a range of impurities, yet they displayed potent antiplasmodial activity. Further study suggested that combination of the MCEs and cyclodepsipeptides elicits a synergistic response and improves antiplasmodial efficacy. This was determined independently using two models, the fixed-ratio isobologram method and the CompuSyn programme based on the massaction law principle. The workflow developed during this investigation demonstrates how new technologies can be used to dereplicate and elucidate bioactive natural products. This workflow can be utilized to continue this research and identify new natural products that can combat malaria
3
BERVANAKIS, GEORGE, and gberva@hotmail com. "DETECTION AND EXPRESSION OF BIOSYNTHETIC GENES IN ACTINOBACTERIA." Flinders University. School of Medicine, 2009. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20090531.033038.
Full textAbstract:
Most microbial organic molecules are secondary metabolites which consist of diverse chemical structures and a range of biological activities. Actinobacteria form a large group of Eubacteria that are prolific producers of these metabolites. The recurrence of pathogens resistant to antibiotics and a wider use of these metabolites apart from their use as anti-infectives, has been the impetus for pharmaceutical companies to search for compounds produced by rare and existing actinobacterial cultures.
Accessing microbial biosynthetic pathway diversity has been possible through the use of sensitive and innovative molecular detection methodologies. The present study evaluated the use of molecular based screening as a rational approach to detect secondary metabolite biosynthetic genes (SMBG) in uncharacterised natural Actinobacterial populations. A polymerase chain reaction (PCR) approach was selected for ease of application and high sample processivity. Rational designed screening approaches using PCR in the discovery of SMBG, involved identifying common functions in secondary metabolite biosynthetic pathways, such as condensation reactions in polyketide synthesis, genes encoding these functions, and using conserved regions of these genes as templates for the design of primers to detect similar sequences in uncharacterised actinobacteria. Design of primers involved rigorous in silico analysis followed by experimentation and validation.
PCR screening was applied to 22 uncharacterised environmental isolates, eight of these displayed the presence of the ketosynthase (KS) gene belonging to the type I polyketide synthases and eight contained the ketosynthase (KSÑ) gene belonging to the type II polyketide synthases, six of the isolates contained the presence of a presumptive dTDP-glucose synthase (strD) gene which is involved in the formation of deoxysugar components of aminoglycoside antibiotics and one isolate contained the presence of a presumptive isopenicillin N synthase (pcbC) gene involved in beta-lactam synthesis. Alignments of partially sequenced PCR products from isolates A1488 and A3023 obtained using type II PKS primers showed close similarities with KSÑ genes from antibiotic producing actinobacteria. Similarly, alignments of sequences from isolates A1113 and A0350 showed regions of similarities to KS genes from antibiotic producing actinobacteria.
Fermentation techniques were used for inducing expression of secondary metabolites from the uncharacterised actinobacteria isolates. By using antimicrobial guided screening it was determined that most of the isolates possessed the capacity to produce antimicrobial metabolites. Dominant antagonistic activity was detected against Gram positive bacteria and to a minor extent against fungi. Optimal fermentation liquid media were identified for certain isolates for the production of antimicrobial metabolites. Two alternative fermentation methods; solid-state and liquid-oil fermentations were evaluated to improve secondary metabolite production in the uncharacterised isolates. Solid-substrate fermentation showed that it could induce a complex metabolite pattern by TLC analysis, however this pattern varied according to the substrate being used. Liquid media supplemented with refined oils, showed a positive response indicated by higher antibacterial activities detected.
Evaluation of semi-purified organic extracts identified two isolates A1113 and A0350 producing similar antimicrobial metabolites as detected by HPLC/UV/MS, a literature database search of similar compounds containing the same molecular weight identified the compound as belonging to the actinomycin group of compounds. A complex metabolic pattern was identified for isolate A2381, database searching identified some of the compounds as having similar molecular weights to actinopyrones, trichostatins, antibiotics PI 220, WP 3688-5 and YL 01869P.
Drug discovery screening can serve to benefit from PCR detection of biochemical genotypes in initial screens, providing a rapid approach in identifying secondary metabolite producing capabilities of microorganisms prior to the commencement of costly and time consuming fermentation studies. Additionally the identification of biochemical genotypes allows a directed approach in using fermentation media designed to induce biosynthetic pathways of specific classes of compounds.
4
Wang, Xiaoling. "Natural product discovery and biosynthesis from soil actinobacteria." Thesis, University of Aberdeen, 2013. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=203796.
Full textAbstract:
New structurally diverse natural products can be discovered when carefully designed screening procedures have been applied and when a prolific organism from a different biological source is examined, such as, rare actinobacteria from an untapped environment. Chapter 3 describes the isolation and structure characterisation of eight compounds from the rare actinobacterum, Saccharothrix xinjiangensis (NRRL B-24321), including, two new 16-member macrolides, Tianchimycin A and B, respectively. OSMAC (One Strain - Many Compounds) is used to search bioactive compounds from the metabolic profile of S. xinjiangensis, isolated from a semi-arid or desert area, Tanchi, Xinjiang in the study. Isolated compounds were characterised by NMR spectroscopy and accurate mass spectrometric analysis. Investigations of the natural products at all levels, from genes, to enzymes, to molecules has revealed insights into differentiating features of the biosynthetic pathways that lead to structural diversity of natural products. The presence of a halogen substituent in natural products profoundly influences their biology activity. Actinomycins are a well-known class of antibiotics/anticancer agents. Here, the gene cluster directing chlorinated actinomycin G biosynthesis in Streptomyces iakyrus (DSM 41873) has been identified and sequenced. It contains one actinomycin synthetase I (ACMS I) gene and two copies of ACMS II and III genes. Genetic analysis demonstrates a unique partnership between the putative hydroxylation and chlorination activities as both acm8 and acm9 genes need to be transcribed for the biosynthesis of actinomycin G2 and actinomycin G3, respectively. In chapter 5, I descries a possible metabolic flux rebalancing pathway for increasing phenazinomycin production in S. iakyrus (DSM 41873) after interruption of the methyltrasfer gene (acmG5') in actinomycin G gene cluster. The gene cluster of phenazinomycin was identified by in silico analysis and by comparison with a known phenazine gene cluster from S. iakyrus (DSM 41873).
5
Garcia, Carlos Eduardo. "Isolamento e identificação de actinobacterias em solos de terra preta antropogenica (TPA) da Amazonia Central por ARDRA e sequenciamento do gene 16S rRNA." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256616.
Full textAbstract:
Orientadores: Fumio Yokota, Tasi Siu MuiTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-05T16:40:59Z (GMT). No. of bitstreams: 1 Garcia_CarlosEduardo_D.pdf: 3424911 bytes, checksum: 6338d2ede1846761521ec0cfb4c5e1ec (MD5) Previous issue date: 2006
Doutorado
Doutor em Ciência de Alimentos
6
Conn, Vanessa Michelle, and vanessa conn@acpfg com au. "Molecular Interactions of Endophytic Actinobacteria in Wheat and Arabidopsis." Flinders University. School of Medicine, 2006. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20060320.171412.
Full textAbstract:
Wheat is the most economically important crop forming one quarter of Australian farm production. The wheat industry is severely affected by diseases, with fungal pathogens causing the most important economic losses in Australia. The application of fungicides and chemicals can control crop diseases to a certain extent, however, it is expensive and public concern for the environment has led to alternative methods of disease control to be sought, including the use of microorganisms as biological control agents. Microorganisms are abundant in the soil adjacent to plant roots (rhizosphere) and within healthy plant tissue (endophytic) and a proportion possess plant growth promotion and disease resistance properties.
Actinobacteria are gram-positive, filamentous bacteria capable of secondary metabolite production such as antibiotics and antifungal compounds. A number of the biologically active endophytes belonging to the Actinobacteria phylum were isolated in our laboratory. A number of these isolates were capable of suppressing the wheat fungal pathogens Rhizoctonia solani, Pythium sp. and Gaeumannomyces graminis var. tritici, both in vitro and in planta indicating the potential for the actinobacteria to be used as biocontrol agents. The aim of this research was to investigate the molecular mechanisms underlying this plant-microbe interaction.
The indigenous microbial populations present in the rhizosphere and endophytic environment are critical to plant health and disruptions of these populations are detrimental. The culture-independent technique Terminal Restriction Fragment Length Polymorphism (T-RFLP) was used to characterise the endophytic actinobacteria population of wheat roots under different conditions. Soils which support a higher number of indigenous microorganisms result in wheat roots with higher endophytic actinobacterial diversity and level of colonisation. Sequencing of 16S rRNA gene clones, obtained using the same actinobacteria-biased PCR primers that were used in the T-RFLP analysis, confirmed the presence of the actinobacterial diversity, and identified a number of Mycobacterium and Streptomyces species. It was found that the endophytic actinobacterial population of the wheat plants contained a higher diversity of endophytic actinobacteria than reported previously, and that this diversity varied significantly among different field soils.
The endophytic actinobacteria have previously been shown to protect wheat from disease and enhance growth when coated onto the seed before sowing. As the endophytes isolated were recognised as potential biocontrol agents, the impact on the indigenous endophytic microbial population was investigated. Utilising the T-RFLP technique it was established that the use of a commercial microbial inoculant, containing a large number of soil bacterial and fungal strains applied to the soil, disrupts the indigenous endophyte population present in the wheat roots. The hypothesis is that non-indigenous microbes proliferate and dominate in the soil preventing a number of endophytic-competent actinobacterial genera from access to the seed and ultimately endophytic colonisation of the wheat roots. This dramatically reduces diversity of endophytes and level of colonisation. In contrast the use of a single endophytic actinobacteria endophyte inoculant results in a 3-fold increase in colonisation by the added inoculant, but does not significantly affect this indigenous population.
Colonisation of healthy plant tissues with fungal endophytes has been shown to improve the competitive fitness with enhanced tolerance to abiotic and biotic stress and improved resistance to pathogens and herbivores. In this study the fungal endophyte population of wheat plants grown in four different soils was analysed using partial sequencing of 18S rRNA gene sequences. Sequence anlaysis of clones revealed a diverse range of fungal endophytes. In this diverse range of fungal endophytes a number sequences were highly similar to those of previously known fungal phytopathogens. A number of sequences detected were similar to fungal species previously identified in soil or plant material but not as endophytes. The remaining sequences were similar to fungal species without a known relationship with plants.
Plants have developed an inducible mechanism of defence against pathogens. In addition to local responses plants have developed a mechanism to protect uninfected tissue through a signal that spreads systemically inducing changes in gene expression. In the model plant Arabidopsis thaliana activation of the Systemic Acquired Resistance (SAR) pathway and the Jasmonate (JA)/Ethylene (ET) pathway is characterised by the production of pathogenesis-related (PR) and antimicrobial proteins resulting in systemic pathogen resistance. Endophytic actinobacteria, isolated from healthy wheat roots in our laboratory, have been shown to enhance disease resistance to multiple pathogens in wheat when coated onto the seed before sowing. Real Time RT-PCR was used to determine if key genes in the SAR and JA/ET pathways were induced in response to inoculation with endophytic actinobacteria.
Inoculation of wild-type Arabidopsis thaliana with selected strains of endophytic actinobacteria was able to �prime� the defence pathways by inducing low level expression of SAR and JA/ET genes. Upon pathogen infection the defence-genes are strongly up-regulated and the endophyte coated plants had significantly higher expression of these genes compared to un-inoculated plants. Resistance to the bacterial pathogen Erwinia carotovora subsp. carotovora was mediated by the JA/ET pathway whereas the fungal pathogen Fusarium oxysporum triggered primarily the SAR pathway.
Further analysis of the endophytic actinobacteria-mediated resistance was performed using the Streptomyces sp. EN27 and Arabidopsis defence-compromised mutants. It was found that resistance to E. carotovora subsp. carotovora mediated by Streptomyces sp. EN27 occurred via a NPR1-independent pathway and required salicylic acid whereas the jasmonic acid and ethylene signalling molecules were not essential. In contrast resistance to F. oxysporum mediated by Streptomyces sp. EN27 occurred via a NPR1-dependent pathway but also required salicylic acid and was JA- and ET-independent.
This research demonstrated that inoculating wheat with endophytic actinobacteria does not disrupt the indigenous endophytic population and may be inducing systemic resistance by activating defence pathways which lead to the expression of antimicrobial genes and resistance to a broad range of pathogens.
7
Schäfer, Jenny [Verfasser]. "Untersuchungen zur Diversität von Actinobacteria in Innenräumen / Jenny Schäfer." Gießen : Universitätsbibliothek, 2012. http://d-nb.info/1063954231/34.
Full text
8
Santos, Luísa Ferreira dos. "Metabolic engineering of actinobacteria for the production of flavours." Thesis, université Paris-Saclay, 2022. http://www.theses.fr/2022UPASL034.
Full textAbstract:
Cette thèse a été réalisée en collaboration avec ENNOLYS, une société de biotechnologies spécialisée dans la production de biomasse, d'enzymes et de molécules aromatiques naturelles. Dans ce contexte, l'objectif principal de ce projet de thèse est l'ingénierie métabolique d'actinobactéries, dont celles du genre Amycolatopsis, pour le développement et l'amélioration de procédés de bioproduction de molécules aromatiques naturelles, dont la vanilline. Pour ce faire, nous avons séquencé le génome de la souche industrielle Amycolatopsis ZYL926 afin de mieux connaitre ses potentialités dans la production de métabolites spécialises ainsi que dans la biosynthèse de la vanilline. De plus, par comparaison de séquence nous avons pu identifier des gènes impliqués dans la dégradation de la vanilline (ou de ces intermédiaires de biosynthèse). Ensuite, nous avons identifié des outils (vecteurs et promoteurs) pour l'insertion et l'expression efficace de gènes hétérologues chez Amycolatopsis. En plus, nous avons développé des outils pour la délétion propre (sans marqueur de résistance) de gènes ou de grandes régions génomiques chez ces bactéries. Ces outils génétiques sont polyvalents et susceptibles d'être utilisés chez de nombreuses espèces du genre Amycolatopsis. Enfin, dans le but d'implémenter une voie de biosynthèse de la vanilline à partir d'un substrat peu coûteux, nous avons choisi et étudié quelques enzymes candidates pour chaque nouvelle étape de biosynthèse. Ces études nous ont permis d'identifier parmi les enzymes candidates celles qui sont actives chez Amycolatopsis dans les conditions de bioconversion utilisées industriellement. De plus, nous avons pu étudier une étape limitante et suggérer des moyens pour améliorer l'efficacité de cette voie de biosynthèseThis thesis was carried out in collaboration with ENNOLYS, a French biotechnology company specialised in the production of biomass, enzymes, and natural aromatic molecules. In this context, the main objective of this thesis project is the metabolic engineering of actinobacteria, including those of the genus Amycolatopsis, for the development and improvement of bioproduction processes for natural aromatic molecules, including vanillin, the most used flavouring agent in the world. To this end, we sequenced the genome of the industrial strain Amycolatopsis ZYL926 in order to better understand the potential of this bacterium in the production of specialised metabolites and in the biosynthesis of vanillin. Furthermore, we were able to identify genes involved in the degradation of vanillin (or of its biosynthetic intermediates) by sequence comparison analysis. Secondly, we have identified genetic tools (including vectors and promotors) for the stable insertion and efficient expression of heterologous genes in Amycolatopsis. In addition, we have developed tools for marker-free deletion of genes or large genomic regions in these bacteria. These genetic tools are versatile and could be used in many species of the genus Amycolatopsis. Finally, in order to implement a vanillin biosynthetic pathway from a low-cost substrate, we selected and studied a few candidate enzymes for each new biosynthetic step. These studies enabled us to identify among the candidate enzymes those which are active in Amycolatopsis under the bioconversion conditions used industrially. In addition, we were able to study a limiting step and suggest ways to improve the efficiency of the studied biosynthetic pathway
9
Mevaere, Jimmy. "Lasso peptides from Actinobacteria - Chemical diversity and ecological role." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066617/document.
Full textAbstract:
Les peptides lasso sont des peptides bioactifs bactériens issus de la voie de biosynthèse ribosomale et subissant des modifications post-traductionnelles, caractérisés par une structure entrelacée dite en lasso. Ils possèdent un cycle macrolactame en position N-terminale, traversé par la queue C-terminale. Cette topologie de type rotaxane, maintenue par piégeage de la queue C-terminale dans le cycle via des acides aminés encombrant et/ou des ponts disulfure, confère à ces peptides une structure compacte et stable. Les actinobactéries recèlent la plus grande diversité et gamme d'activités biologiques parmi les peptides lasso (antibactériens, anti-VIH, antagonistes de récepteurs..), et l'exploration de génomes suggère une diversité encore plus grande, puisque certains clusters portent des gènes codant des enzymes de modifications post-traductionnelles jamais observées auparavant. Cependant, l'expression de ces peptides semble être rigoureusement contrôlée, rendant leur production en laboratoire difficile à partir de la bactérie productrice. Le rôle écologique et les mécanismes de régulation des peptides lasso ne sont pas très documentés. Leur compréhension permettrait d'améliorer la production et de mieux exploiter les activités biologiques des peptides lassoLasso peptides are ribosomally synthesized and post-translationally modified peptides produced by bacteria, characterized by a remarkable mechanically-interlocked structure. The lasso topology, reminiscent to a rotaxane, consists in an N-terminal macrolactam ring threaded by a C-terminal tail. This compact and stable structure is stabilized by steric entrapping of the tail in the ring, through bulky amino acid(s) and/or disulphide bonds. Lasso peptides produced by Actinobacteria display the greatest chemical diversity and a range of biological activities (antibacterial, anti-HIV, receptor antagonist…), therefore are of high pharmaceutical interest. Genome mining revealed that Actinobacteria have enormous potential to biosynthesize novel lasso peptides, e.g. harbouring new post-translational modifications. However, the expression of these peptides is generally controlled by complex regulatory systems, making their production under laboratory conditions difficult. Understanding the ecological role and regulation mechanisms of lasso peptides would help to improve production and better exploit the biotechnological potential of these molecules. The first part of my work deals with the identification of new lasso peptides from Actinobacteria, using heterologous expression in Streptomyces hosts. The second part of my work deals with the regulation mechanism and ecological role of lasso peptides using sviceucin, a lasso peptide produced by Streptomyces sviceus, as the model for study
10
Silva, ValÃria Maria AraÃjo. "Facilitation can increase actinobacteria adaptation capacity and rhizobia "in vitro"." Universidade Federal do CearÃ, 2016. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=17158.
Full textAbstract:
Secretaria da EducaÃÃo do CearÃThe natural environment is marked by an intricate network of biotic interactions that shape the structure of ecological communities. The presence of positive ecological interactions between microbial populations in soils semiarid regions, has great importance in structuring the local soil microbiota. In this work, actinomycetes strains of rhizobia and coming from rhizosphere of Park National Ubajara-CE, were evaluated for the ability to grow through cooperative metabolic mechanisms. Of the 27 evaluated actinomycetes, 22 showed compatibility with rhizobia. The strains UB-05, UB-07, UB-08, UB-11 and UB-21 stood out in facilitating tests for amylase and cellulase. The metabolic activity of actinomycetes helped the development of rhizobia strains
O ambiente natural à marcado por uma intrincada rede de interaÃÃes biÃticas que moldam a estrutura das comunidades ecolÃgicas. A presenÃa de interaÃÃes ecolÃgicas positivas entre populaÃÃes microbianas em solos de regiÃes semiÃridas, possui grande relevÃncia na estruturaÃÃo da microbiota do solo local. Neste trabalho, cepas de actinobactÃrias e rizÃbios oriundas de solo rizosfÃrico do Parque Nacional de Ubajara-CE, foram avaliadas quanto à capacidade de crescerem atravÃs de mecanismos metabÃlicos cooperativos. Das 27 actinobactÃrias avaliadas, 22 apresentaram compatibilidade com rizÃbios. As cepas UB-05, UB-07, UB-08, UB-11 e UB-21, destacaram-se nos ensaios de facilitaÃÃo para amilase e celulase. A atividade metabÃlica de actinobactÃrias auxiliou o desenvolvimento das cepas de rizÃbios.
11
Sanyika, Walter Tendai. "Comparison of actinobacterial diversity in Marion Island terrestrial habitats." Thesis, University of the Western Cape, 2008. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_2619_1263423621.
Full text
12
Moody, Suzy Clare. "Exploring the roles of novel secondary metabolites in Streptomycetes." Thesis, Swansea University, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.678483.
Full text
13
Mokhtar, Noor Azlin. "Investigations of triacyglyceride metabolism amongst actinomycete isolates from Peninsular Malaysia." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609654.
Full text
14
Spadari, Cristina de Castro. "Bioprospecção de uma substância antifúngica potencialmente nova produzida por actinomicetos isolados no RS." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2013. http://hdl.handle.net/10183/79634.
Full textAbstract:
Os fungos dermatófitos e as leveduras do gênero Candida são alguns dos microrganismos responsáveis por micoses em humanos. O tratamento dessas doenças acaba se tornando difícil pelo baixo número de antifúngicos existentes no mercado e pelo surgimento de resistência destes às drogas utilizadas. Já as actinobactérias são conhecidas por produzirem uma grande variedade de metabólitos secundários. Este trabalho teve como objetivo avaliar a atividade antifúngica dos metabólitos secundários produzidos por isolados de actinomicetos contra fungos dermatófitos e espécies de Candida sp. de origem clínica. Para a seleção dos isolados de actinomicetos com o melhor potencial de inibição foi realizado o ensaio de dupla camada em meio ágar amido caseína (ACA). Os isolados que mostraram atividade foram submetidos aos ensaios para a otimização da produção do composto ativo em sistema de cultura submersa. Para isso, foram avaliados diferentes meios de cultura, diferentes temperaturas e diferentes faixas de pH. A atividade antifúngica foi avaliada a cada 24h durante oito dias e observada através do ensaio de difusão em poço, onde foi calculado o índice de antibiose (IA). Nenhum dos isolados de fungos dermatófitos foi inibido no ensaio de dupla camada e os isolados 1S, R18(6) e 6(2) demonstraram atividade frente todas as espécies de Candida testadas. O isolado R18(6) mostrou melhor atividade em cultura líquida, sendo que as melhores condições de cultivo para a produção do antifúngico foi meio AC sem controle de pH, temperatura de 30°C e crescimento por 72h. Foram realizados ensaios como a concentração inibitória mínima, teste de termoestabilidade e avaliação do efeito de enzimas na atividade antifúngica do extrato bruto. O extrato bruto padronizado foi submetido à cromatografia de camada delgada (CCD) com diferentes solventes e o ensaio de autobiografia foi realizado para verificar a banda com atividade antifúngica. O composto ativo foi observado em um Rf de 0,35 quando utilizado como solvente a mistura de butanol/ ácido acético/ água. Após identificar a banda com atividade antifúngica foram realizados testes de coloração da CCD com cloreto férrico, ninhidrina e anisaldeído para identificação parcial do composto ativo. O resultado sugere que o composto não possui hidroxilas ligadas a anel aromático, não apresenta grupo amino livre e possivelmente alguma parte da molécula tenha um anel heterocíclico com nitrogênio ligado. Também, foi realizada a caracterização morfológica do isolado R18(6) através de microcultivo e microscopia eletrônica de varredura (MEV) e foram observadas estruturas características do gênero Streptomyces.The dermatophytes fungi and Candida species are some of the microorganisms responsible for mycoses in humans. The treatment of these diseases eventually becomes difficult by the low number of antifungal agents in the market and by the emergence of resistance to the drugs available today. The actinobacteria are known by producing different secondary metabolites. This study aimed to evaluate the antifungal activity of secondary metabolites produced by actinomycetes isolates against fungal pathogens of clinical origin. For the selection of actinomycetes isolates with the best potential inhibition the assay of double layer was performed on starch casein agar (SCA). The isolates that showed activity were submitted to an optimization of the active compound production in submerged culture system. In order to do so, different culture media, temperatures and pH ranges were assessed. The antifungal activity was evaluated every 24 hours for eight days and activity was observed by well diffusion assay, where the antibiosis index was calculated. None of the dermatophyte isolates were inhibited in the double layer assay. Isolates 1S, R18(6) and 6(2) of the actinobacteria demonstrated activity against all the tested Candida species. Isolate R18(6) showed the highest activity in liquid culture and the best growing conditions for producing the antifungal compound was media starch casein broth , without pH control, temperature of 30°C with 72h of cell growth. Assays were performed as the minimum inhibitory concentration, thermal stability test and the effect of different enzymes on antifungal activity of the crude extract. The crude extract was subjected to standardized thin layer chromatography (TLC) with different solvents and an autobiography assay was conducted to verify band with antifungal activity. The active compound was observed at an Rf of 0.35 when the solvent mixture of butanol/ acetic acid/ water was used. After identifying the band with antifungal activity CCD coloring tests were performed with ferric chloride, anisaldehyde and ninhydrin for partial identification of the active compound; it has been observed that the compound does not have hydroxyl groups attached to the aromatic ring, it has no free amino group and possibly some part of the molecule has a linked nitrogen heterocyclic ring. Also, we performed a morphological characterization of the isolate R18 (6) through microcultive and scanning electron microscopy and structures have been observed characteristics of the genus Streptomyces.
15
Souza, Alessandra Zanin Zambom de 1987. "A suplementação via oral com L-glutamina altera a composição da microbiota intestinal de indivíduos sobrepesos e obesos." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/244481.
Full textAbstract:
Orientador: Patricia de Oliveira PradaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Aplicadas
Made available in DSpace on 2018-08-26T02:10:44Z (GMT). No. of bitstreams: 1 Souza_AlessandraZaninZambomde_M.pdf: 4234168 bytes, checksum: b7f596f6fcaa8a1d60980a17c3aeb76d (MD5) Previous issue date: 2014
Resumo: Introdução: Inúmeros fatores contribuem para o aumento da obesidade em todo o mundo. Recentemente, a microbiota intestinal ganhou destaque devido ao seu poder de predispor ou inibir o ganho de peso. Alguns nutrientes são capazes de alterar a composição da microbiota intestinal, o que pode trazer efeitos benéficos ou maléficos, como a obesidade. O aminoácido L-glutamina, além de suas inúmeras funções orgânicas e imunológicas, é conhecido por desempenhar importante papel no trofismo intestinal. O objetivo do presente estudo foi investigar alterações na composição da microbiota intestinal de indivíduos com sobrepeso ou obesidade após suplementação oral com L-glutamina. Métodos: Voluntários com sobrepeso ou obesidade foram selecionados para ingerir 30g de L-glutamina (GLN) por via oral ao dia, por um período de quatorze dias. O grupo controle recebeu L-alanina (ALA) no mesmo tempo e proporção. Amostras de sangue e fezes foram coletadas para análises. Para classificação taxonômica das bactérias intestinais, foi realizado sequenciamento do gene 16S RNA ribossomal. Análises de bioinformática foram conduzidas com base no banco de dados RDP (Ribosomal Database Project). Para análise dos dados, estratégias estatísticas variadas foram utilizadas. Resultados: Após quatorze dias de suplementação, os participantes do grupo GLN exibiram diferenças significativas nos filos Actinobacteria e Firmicutes e nos gêneros Dialister, Dorea, Pseudobutyrivibrio e Veillonella, comparados com o grupo ALA. A razão F / B (Firmicutes / Bacteroidetes), um bom biomarcador para a obesidade, reduziu de 0,85 para 0,57 no grupo GLN e ao contrário, aumentou de 0,91 para 1,12 no grupo ALA. Conclusão: A suplementação oral do aminoácido L-glutamina, em humanos com sobrepeso e obesidade, por um período de quatorze dias, promove alterações na composição da microbiota intestinal similares às promovidas pela perda de peso
Abstract: Introduction: Several factors contribute to the increase of obesity worldwide. Recently, the gut microbiota gained prominence due to its power to predispose or inhibit weight gain. Some nutrients are able to change the composition of the gut microbiota, what can bring beneficial or harmful effects, such as obesity. The amino acid L-glutamine, in addition to its numerous organic and immune functions, is known to play an important role in intestinal tropism. The aim of this study was to investigate changes in the composition of the gut microbiota of overweight or obese adults after oral supplementation with L-glutamine. Methods: Overweight or obese subjects were selected to orally ingest 30g of L-glutamine (GLN) daily for a period of fourteen days. The control group received L-alanine (ALA) in the same period and proportion. Blood and feces were collected for analysis. The 16S rRNA gene sequence was performed for taxonomic classification of intestinal bacteria. Bioinformatics analysis was conducted based on RDP (Ribosomal Database Project). For data analysis, varied statistical strategies were used. Results: After fourteen days of supplementation, participants in the GLN group showed significant differences in the Firmicutes and Actinobacteria phyla and Dialister, Dorea, Pseudobutyrivibrio and Veillonella genera, compared with the ALA group. The F / B (Firmicutes / Bacteroidetes) ratio, a good biomarker for obesity, decreased from 0.85 to 0.57 in GLN group and, as opposed, increased from 0.91 to 1.12 in the ALA group. Conclusion: Oral supplementation with the amino acid L-glutamine in overweight and obese humans, for a period of fourteen days, alters the composition of the gut microbiota in a similar way to weight loss
Mestrado
Nutrição
Mestra em Ciências da Nutrição e do Esporte e Metabolismo
16
Sfarlea, Iulia. "Isolation and characterisation of indigenous actinobacteria from diverse South African environments." Master's thesis, University of Cape Town, 2010. http://hdl.handle.net/11427/16396.
Full textAbstract:
One soil sample and various indigenous plant and seaweed samples were used to isolate actinobacteria, with a particular focus on isolating rarer actinobacteria (non-Streptomyces species). A total of 169 putative actinobacterial strains was isolated, of which 42 were selected, based on their morphology, for further identification using a rapid molecular identification method and/or 16S rRNA gene sequence analysis. This includes seven strains isolated from various plant and seaweed samples. A total of 28 non-Streptomyces species was identified, with 23 being isolated from the soil sample, four isolated as plant endophytes (strains SM3BL 1, YPC1, YPC2 and YPL 1), and one isolated as a seaweed epiphyte (Y2UE1). Two Streptomyces species were isolated as endophytes (with strain SC1 isolated from a seaweed sample, and YMH1 isolated a plant species). Forty-two strains, including all non-Streptomyces species, were screened for their antibacterial activity against Mycobacterium aurum A+. Six strains showing promising antibacterial activity were selected for antibiotic extraction. The strains were also investigated for their antibiotic biosynthetic potential by PCR screening for the genes for ansamycin, glycopeptide and Type II (aromatic) polyketide antibiotics. Amplification of the AHBA synthase gene (ansamycin biosynthesis) was achieved for strains SE22 and YPC1. Strains SE22 and YMH1 were positive for the presence of the KSα-KSβ gene pair, with strain SE22 potentially producing a Type II (aromatic) polyketide. The gene product of isolate YMH1 was identified as a spore pigment gene. Antibiotic extraction was successful for strains SE22 and YM55, with numerous active compounds isolated from strain SE22, and one active compound isolated from strain YM55. Fifteen strains were selected for full characterisation based on their isolation source, their identification to non-Streptomyces genera and/or their antibacterial activity. These included four Micromonospora strains, three Kribbella strains, three Streptomyces strains, one Actinomadura strain, one Kineococcus strain, one Nocardia strain, one Nonomuraea strain and one Verrucosispora strain. Two previously isolated Microbispora strains were also characterised. The 17 strains were subjecte d to 16S rRNA gene sequence analysis to determine their closest phylogenetic relatives. The use of gyrB gene based phylogeny was also investigated for the two Microbispora isolates, resulting in a more stable phylogenetic tree. However, differences observed between the 16S rRNA and gyrB gene tree topologies suggest that horizontal gene transfer has occurred within the genus. The 17 isolates were distinguished from their closest phylogenetic neighbours through morphological and physiological characteristics. It is likely that the majority of the isolates are novel, although 16 isolates will require DNA-DNA hybridisation studies to determine if they are new species. Actinomadura strain YPC2 may be proposed as a novel species without the need for DNA-DNA hybridisation.
17
Belyaevskaya, Anna V. "Characterization of T box riboswitch gene regulation in the phylum Actinobacteria." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1437725058.
Full text
18
Tawfik, Rahmy. "A Novel Approach to the Discovery of Natural Products From Actinobacteria." Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/6766.
Full textAbstract:
Actinobacteria, primarily the genus Streptomyces, have led to the development of a number of antibiotics, which result from their secondary metabolites or modified derivatives. Secondary metabolite production can result from competition with neighboring microbes in an effort to disrupt growth, aiding in the competition for vital nutrients in impoverished conditions. Such secondary metabolites have the potential to affect a plethora of cellular functions in target cells, including, cell wall development, protein synthesis, protein function and fatty acid synthesis/metabolism. Due to the pandemic spread of antibiotic resistant bacteria, it is imperative to continue the search for new therapeutic agents targeting these deadly organisms. As such, our group explored soil and marine samples from Tampa Bay’s surrounding farmlands and waterways for secondary metabolite producing microbes using culture methods specific to Actinobacteria. Through these efforts we isolated over 750 bacterial species, of which almost half are confirmed Actinobacteria. In an attempt to derive new and novel chemistry from these organisms, we used our novel collection, and developed techniques for epigenetic modification to un-silence dormant and cryptic metabolic pathways. Our work reveals that a number of these Actinobacteria produce secondary metabolites that are effective against the ESKAPE pathogens, some at very low concentrations. Although the bioactivity from secondary metabolites is a well-known source for antibiotic drug discovery, our epigenetic methods suggest a potential to isolate previously overlooked compounds that have a very real possibility for use as antibacterial therapeutics.
19
Maake, Takalani Whitney. "Development of an actinobacteria based in vitro transcription and translation systems." University of the Western Cape, 2015. http://hdl.handle.net/11394/4750.
Full textAbstract:
>Magister Scientiae - MScHeterologous metagenomic screening strategies have relied largely on the construction of DNA libraries and screening in Escherichia coli to access novel enzymes. There is an increased demand for the identification of novel lignocellulose degrading enzymes with enhanced biochemical properties which are suitable for applications in industrial processes; biofuels being one of them. The use of heterologous gene expression in function based metagenomic studies has resulted in the discovery of enormous novel bioactive compounds. However, there are limitations associated with using E. coli as a heterologous host which does not allow transcription and translation of all genes in the metagenome. E. coli can only express 40% of the environmental DNA because of promoter recognition, codon usage, and host toxicity of gene products. Therefore alternative strategies for expressing or producing novel enzymes are needed, which can also be employed in metagenomic gene discovery. In vitro protein synthesis is an important tool in molecular biology and used to obtain proteins from genes for functional and expression studies. These systems may hold the key to unlock more of the potential in metagenomic DNA. The broader aim of the study is to develop non- E. coli based cell-free protein synthesis systems to further the metagenomics screening. In this study, Rhodococcus erythropolis H8 was evaluated for its suitability in cell-free expression. Crude extracts containing the macromolecular components (70S or 80S ribosomes, tRNAs, initiation, elongation and termination factors) fromR. erythropolis were prepared using existing crude extract based cell-free protein synthesis (CFPS) protocols. Three genes were selected and used as templates for synthesis: cell11, xp12 and acetyl xylan esterase (axe10), all previously isolated from metagenomic libraries screened inE. coli. As judged by zymograms and enzyme assays, all enzymes were successfully expressedfrom their native promoters and in recombinants clones using the PtipA promoter, and wereactive. Furthermore, the amounts of XP12 protein produced using pFos-XP_12 was 1.2mg/mlfrom E. coli and 1.67mg/ml from R. erythropolis CFPS, showing that the R. erythropolismachinery was more efficient in the expression of XP12 than the E. coli machinery. To the best of our knowledge this is the first demonstration of a cell-free expression using an actinomycete.
20
Lacey, Heather Jane. "Hidden Underworld: A Study Of Secondary Metabolites From Soil-Derived Actinobacteria." Thesis, The University of Sydney, 2022. https://hdl.handle.net/2123/29524.
Full textAbstract:
Natural products have played a key role in drug discovery and pharmacotherapy for a range of infectious, non-infectious, and lifestyle diseases. Despite the sophisticated synthetic technology now available to produce diverse chemical entities, novel chemical scaffolds are in short supply.
High-performance liquid chromatography with diode-array detection (HPLC-DAD) and bioassay guided bioprospecting are investigative methods to discover the novel secondary metabolites of organisms. A library of 50,000 biologically active microbes was previously constructed, each of which produces high levels of secondary metabolites with a diverse array of UV spectra. From this collection, three soil Actinobacteria, Streptomyces sp. MST-91080, Streptomyces sp. MST-RA15507 and Amycolatopsis sp. MST-135876v3 were chosen for further investigation described in this thesis. A rich diversity of secondary metabolites has been uncovered.
Spectroscopic structural elucidation and bioactivity profiling of Streptomyces sp. MST-91080 led to the discovery of six novel conglobatin analogues, conglobatins B1 (91), C1 (92), C2 (93), D1 (94), D2 (95) and E (96), a family of four tri-alkyl substituted aromatic acids, named after yeppoonic acids A – D (106 – 109), and resorculins A (127) and B (128).
Research into Streptomyces sp. MST-RA15507 enabled the isolation of a family streptospiroles, previously reported compounds streptospiroles A – C (144 – 146) and des-chloro armeniaspirole C (148), plus a novel analogue armeniaspirol C2 (147). Halogen substitution experiments were undertaken to produce brominated analogues streptospiroles E, H and K (149 – 151), and full spectroscopic characterisation of all these compounds were undertaken, since this was previously absent from the literature.
Finally, exploration of the metabolite profile of Amycolatopsis sp. MST-135876v3 led to the isolation and characterisation of two families of chlorinated cyclic hexapeptides pamplonatides A (159) and B (160), and suertide A (161). Brominated analogues of these compounds were generated, using successful hydrogen substitution experiments, which led to the isolation of bromo-analogues pamplonatide C (160), suertide B (163), and suertide C (164).
Taken together, the results published have enriched our understanding of secondary metabolite production by demonstrating the sophistication of microbial biosynthesis and the ongoing potential for chemical novelty of soil derived, novel Actinobacteria in the treatment of disease
21
Elsayed, Somayah Sameer. "Chemical characterisation of microbial natural products from underexplored habitats." Thesis, University of Aberdeen, 2015. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=227107.
Full text
22
Matsuura, Takeshi. "Caracterização taxonomica de actinomicetos endofiticos produtores de antibioticos isolados de cupuaçuzeiro (Theobroma grandiflorum Schum.) : Takeshi Matsuura." [s.n.], 2004. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256663.
Full textAbstract:
Orientadores: Gilson Paulo Manfio, Valeria Maia de OliveiraTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-04T00:38:31Z (GMT). No. of bitstreams: 1 Matsuura_Takeshi_D.pdf: 1138022 bytes, checksum: 8ba7f70e7073ab53765ddce2a0027439 (MD5) Previous issue date: 2004
Doutorado
Doutor em Ciência de Alimentos
23
Sanchez, Beatriz Lisboa. "Fungos negros do tegumento de formigas atíneas derivadas e suas interações com actinobactérias /." Rio Claro, 2019. http://hdl.handle.net/11449/181632.
Full textAbstract:
Orientador: Andre RodriguesCoorientador: Fernando Carlos Pagnocca
Banca: Derlene Attili de Angelis
Banca: Vania Aparecida Vicente
Resumo: Os fungos negros são conhecidos por apresentarem melanina na parede celular, a qual proporciona resistência a diversos estresses ambientais. Nos últimos anos, foram descobertas várias associações entre formigas e fungos negros da ordem Chaetothyriales. No caso das formigas cultivadoras de fungos (atíneas), tais associações permanecem pouco exploradas. Fungos próximos ao gênero Cyphellophora (ex-Phialophora), encontrados no tegumento de formigas do gênero Apterostigma (uma atínea basal), inibem as actinobactérias simbiontes presentes no mesmo local, sendo considerados nocivos para as colônias dessas formigas. Por outro lado, espécies de fungos negros da mesma ordem foram encontradas em baixa abundância no tegumento de alados de Atta (uma atínea derivada). Nesse contexto, pouco se sabe sobre a abundância, diversidade e relação ecológica desses fungos em outros gêneros de atíneas derivadas. Este trabalho teve como objetivo descrever a presença e relação ecológica dos fungos negros no tegumento desses insetos. Utilizando dois métodos dependentes de cultivo, avaliamos a diversidade de fungos negros do tegumento de Acromyrmex coronatus (cortadeira de folhas) e Trachymyrmex tucumanus (não-cortadeira de folhas). Após o isolamento, os fungos foram purificados e identificados com base no sequenciamento da região ITS e um fragmento do gene tef1. Em seguida, foram realizados testes de co-cultivo in vitro entre quatro actinobactérias frente aos fungos negros obtidos das mesmas espécies de... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Black fungi are known for the presence of melanin in their cell walls, which provides resistance to different types of environmental stresses. Recently, many associations between ants and black fungi in the order Chaetothyriales have been discovered. When it comes to fungus-growing ants (the "attines"), these associations remain underexplored. Fungi related to the genus Cyphellophora (ex-Phialophora), found on the integument of Apterostigma ants (lower attines), inhibit the symbiotic actinobacteria also present on the ant integument, and for that are considered detrimental for the ant colonies. However, black fungi species belonging to the same order were found in low abundance on the integument of gynes and drones of Atta (higher attines). In this context, little is known about the abundance, diversity and ecological relation of these fungi in other genera of derived attines. The aim of this study was to describe the presence and ecological relation of black fungi on the integument of these insects. By applying two different culture dependent methods, we evaluated the diversity of black fungi on the integument of Acromyrmex coronatus (leafcutter) and Trachymyrmex tucumanus (non-leafcutter). After isolation, fungi were purified and identified based on ITS region and partial tef1 gene sequences. Next, we put together in vitro co-culture assays between four actinobacteria and black fungi obtained from the same ant species. We found 111 black fungi in both species of ants, inclu... (Complete abstract click electronic access below)
Mestre
24
Sottorff-Neculhueque, Ignacio [Verfasser]. "Diversity of Easter Island Actinobacteria and their secondary metabolites / Ignacio Sottorff-Neculhueque." Kiel : Universitätsbibliothek Kiel, 2019. http://d-nb.info/1188612042/34.
Full text
25
Som, Nicolle. "MtrAB-LpqB : a conserved pathway regulating cell division in the phylum Actinobacteria?" Thesis, University of East Anglia, 2016. https://ueaeprints.uea.ac.uk/64007/.
Full textAbstract:
Streptomyces are ubiquitous in soil and face a rapidly changing environment. Like other bacteria, they sense and respond to external stimuli via two component systems and Streptomyces species encode a particularly high number of these systems. One of these two component systems is called MtrAB-LpqB and it is highly conserved in the phylum Actinobacteria. Previous work in Mycobacterium tuberculosis, Corynebacterium glutamicum and Streptomyces coelicolor indicates that MtrAB-LpqB is involved in osmosensing and cell cycle progression. To investigate the function of MtrAB-LpqB I attempted to make single gene deletions in the new model organism Streptomyces venezuelae. I also performed chromatin immunoprecipitation and sequencing (ChIP-seq) against MtrA-3xFlag in S. venezuelae and S. coelicolor to identify the regulon of genes under its control. I present evidence that MtrA is essential in S. venezuelae whereas MtrB is dispensable. It was not possible to confirm deletion of lpqB. Deletion of mtrB activates MtrA and leads to the overproduction of cryptic secondary metabolite biosynthetic gene clusters (BGCs). The same effect was achieved by introducing a gain of function MtrA protein into the S. venezuelae wild-type strain. The cryptic BGCs are activated because MtrA binds to target genes spanning 85% of the BGCs in S. venezuelae and S. coelicolor. In Streptomyces, antibiotic production is linked to development and the MtrA regulon overlaps with the master regulator of development, BldD. The results presented here suggest that MtrAB senses external signals and modulates target gene expression to coordinate development with the production of secondary metabolites.
26
França, Aline Giovana da. "Filo Actinobacteria e abundância do gene alkB em solos rizosféricos cultivados sob sistemas de colheita de cana-de-açúcar." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/64/64133/tde-29112017-102300/.
Full textAbstract:
O filo Actinobacteria é, atualmente, considerado um dos maiores filos pertencentes ao domínio Bacteria. Este filo pode representar até 30% da comunidade microbiana do solo. Os organismos do filo Actinobacteria tem sido caracterizados como produtores de antibiótico e degradadores de substâncias complexas como os alcanos, presente em diversas substâncias encontradas em plantas. Em relação à degradação dos alcanos já tem sido comprovado que o gene alkB (alcano hidroxilase), presente no filo Actinobacteria, está relacionado a sua degradação. Porém, as comunidades de tais organismos podem ser alteradas por mudanças no uso do solo, que no Brasil ocorrem extensivamente devido a implantação de monoculturas. A cultura de cana-de-açúcar, que vem se expandido anualmente, se mostra como uma das culturas que podem alterar a microbiota do solo. Os diferentes sistemas de colheita de cana-de-açúcar, com e sem a queima da palhada, podem alterar a microbiota do solo. Assim, considerando o papel do filo Actinobacteria na ciclagem de matéria orgânica, além da sua importância biotecnológica, este trabalho avaliou como os diferentes sistemas de colheita da cana-de-açúcar influenciam as comunidades rizosféricas de Actinobacteria e de bactérias oxidadoras de alcano, sob condições controladas em casa de vegetação, utilizando técnicas moleculares para quantificar (qPCR), análisar a estrutura (T-RFLP) e a diversidade da comunidade (sequenciamento de metagenoma). Para isso o solos coletado de áreas de plantação de cana-de-açúcar com os manejos de colheita com e sem queima da palhada, foram utilizados em experimento de mesocosmos composto por vasos com planta, de onde foi coletado solo rizosférico, e vaso sem planta, de onde foi coletado solo controle. A quantificação dos gene 16S rRNA de Actinobacteria e do gene alkB não mostraram diferenças estatística nas comparações dos solos controles de cana-de-açúcar com e sem queima, e na comparação entre os solos rizosférico e controle de cada tipo de manejo de colheita. A análise dos Fragmentos Terminais de Restrição (TRFs) dos solos controle dos diferentes sistemas de colheita, mostraram uma separação da comunidade bacteriana presente no solo, o mesmo ocorreu nas comparações entre os solos rizosférico e controle de diferentes manejos de colheita. Porém, quando se observa a estrutura taxonômica da comunidade bacteriana nota-se que os filos Proteobacteria, Actinobacteria, Firmicutes e Acidobacteria são predominantes nos diferentes solos amostrados, as diferenças estatísticas entre os solos controle e rizosférico de cada tratamento se apresentam a partir da análises das famílias bacterianas presentes nos solos. Para o gene alkB, as sequências encontratas nos diferentes solos pertencem aos dois filos mais abundantes nos solos, os filo Proteobacteria e Actinobacteria, porém algumas sequências pertencem a bacterias não identificadas. Assim, conclui-se que as mudanças na estrutura da comunidade bacteriana presente em solo com monocultura da cana-de-açúcar são perceptíveis a partr da análises de grupos filogenéticos mais baixo e que a comunidade de bactéria degradadoras de alcanos são pertencentes, principalmente, os filos Actinobacteria e Proteobacteria, porém ainda é necessário mais estudos para a classificação das bactérias não identificadasThe phylum Actinobacteria is currently considered one of the major phyla belonging to the domain Bacteria. This phylum can represent up to 30% of the soil microbial community. The organisms of the phylum Actinobacteria has been characterized as antibiotic producers and degraders of complex substances such as alkanes, present in several substances found in plants. Regarding the degradation of alkanes it has already been proven that alkB gene (alkane hydroxylase), present in the phylum Actinobacteria, is related to its degradation. But the communities of such organisms can be altered by changes in land use, which in Brazil occur extensively due to implementation of monocultures. The cultivation of sugarcane, which has been expanded annually, appears as one of the crops that can alter the soil microbiota. The different sugarcane harvest systems, with and without straw burning, can alter the soil microbiota.Thus, considering the role of the phylum Actinobacteria in the cycling of organic matter, in addition to their biotechnological importance, this study evaluated how different harvest systems of sugarcane influence rhizospheric communities of Actinobacteria and alkane-oxidizing bacteria under controlled conditions in a greenhouse, using molecular techniques to quantify (qPCR), analyse the structure (T-RFLP) and diversity of the community (metagenomic sequencing). For this, the soil collected from sugarcane fields with harvest managements with and without burning the straw, was used in a mesocosms experiment composed of pots with a sugarcane plant, from where rhizosphere soil was collected, and without plant, from where control soil was collected. The quantification of Actinobacteria 16S rRNA gene and alkB gene showed no statistical differences in the comparison of sugarcane controls soil with and without burning, and in the comparison between rhizosphere and control soil of each type of crop management. Terminal Restriction Fragments (TRF) analysis of control soils of different harvesting systems showed a separation of the bacterial community present in the soil, the same occurred in the comparison between rhizosphere and control soils of different harvesting systems. However, when observing the taxonomic structure of the bacterial community it is noted that that the phyla Proteobacteria, Actinobacteria, Firmicutes and Acidobacteria are predominant in different sampled soils, the statistical differences between the control and rhizosphere soil of each treatment are presented from the analysis of bacterial families present in the soil. For alkB gene, the sequences found in different soils belong to the two most abundant phyla in the soil, the phylum Proteobacteria and Actinobacteria, but some sequences belong to unidentified bacteria.Thus, it is concluded that the changes in the structure of the bacterial community present in soil with monoculture of sugarcane are apparent from the analysis of lower phylogenetic groups and the alkane-degrading bacterial communities belong mainly to the phyla Actinobacteria and Proteobacteria, however it is still needed further studies for the classification of unidentified bacteria
27
Tangeman, Lorraine Susan. "Can Antibiotics From Recently Discovered Marine Actinobacteria Slow the Tide of Antibiotic Resistance?" Wright State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=wright1377522942.
Full text
28
Pelser, James Grant. "Screening environmental actinobacteria for antimycobacterial antibiotics and characterisation of Kribbella stellenboschensis sp. nov." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29202.
Full textAbstract:
Soil was collected from a compost heap in a Mowbray suburban garden and a compost heap in a Plumstead suburban garden. The soil and ‘worm tea’ of a vermiculture farm from the same Mowbray suburban garden were also sampled. Using four different types of media (7H9, CZ, ISP2 and GOT) 135 isolates were putatively identified as actinobacteria based on colony morphology. These isolates were screened for antimycobacterial activity against the test bacterium Mycobacterium aurum A+. A Kribbella strain, isolated and identified by an intern in the lab, and a Micromonospora strain, isolated and identified during the authors Honours project, were also screened for antimycobacterial activity. Sixty-four (64) actinobacterial isolates displayed moderate antibiotic activity or higher (ZOI >1001 mm2 ) based on the standard overlay method. Kribbella strain SK5 displayed very strong antimycobacterial activity (3309 mm2 ). Forty (40) of the actinobacterial strains that exhibited moderate/strong/very strong antimycobacterial activity and/or had interesting morphological features were selected for genus identification via a standard nucleotide-nucleotide blastn analysis of their 16S rRNA gene sequences. Thirty-one (31) strains were identified as Streptomyces species, six strains were identified as Micromonospora species, one strain was identified as a Nocardia species, one strain was identified as a Kitasatospora species, and one strain was identified as a member of the genus Tsukamurella. These isolates were subjected to phylogenetic analysis using the partial 16S rRNA gene sequences. Based on analysis of the 16S rRNA gene sequences, Streptomyces strain PR10 was found to be the most interesting of the Streptomyces isolates and should be pursued as a novel species (99.7% sequence similarity to the top blastn hit and less than 98.8% sequence similarity from the third blastn hit onwards). Further analysis of the gyrase subunit B (gyrB) gene sequence of the Kitasatospora isolate (strain PR3) revealed that the isolate is more closely related to members of the genus Streptomyces. Further evidence to support the assignment of strain PR3 to the genus Streptomyces (rather than Kitasatospora) is that it has two Streptomyces-specific gyrB gene indels signatures. Tsukamurella strain G4 was noted for characterisation as a novel species. The potential for seven isolates to produce ansamycin, glycopeptide, non-ribosomal peptide, and/or TypeII polyketide antibiotics was determined by detection of antibiotic biosynthetic gene clusters using PCR. Strain M27 demonstrated the potential to produce all the aforementioned antibiotics. Strain Y10 demonstrated the potential to produce a non-ribosomal peptide antibiotic. Strains PR10, PR28, PR47 and UK1 demonstrated the potential to produce Type-II polyketide and non-ribosomal peptide antibiotics. The PCR products were sequenced and analysed via blastn to compare them to the known antibiotic biosynthetic gene sequences in the GenBank database. The non-ribosomal peptide synthetase (NRPS) A domain sequences were analysed using the NRPSpredictor2 software to identify the A domain substrate specificity Solvent extraction was done on the broth cultures of Streptomyces strains PR3, UK1 and Y30 and Kribbella strain SK5 to isolate the antimycobacterial compounds. It was found that the cell mass extract of the three Streptomyces isolates had active compounds against M. aurum A+. The culture broth extract of the Kribbella isolate was found to have an active compound against M. aurum A+ and Staphylococcus aureus ATCC 25923. One-dimensional and two-dimensional TLC of the culture broth extract from strain SK5 revealed that a single compound was active against M. aurum A+ and S. aureus ATCC 25923. Nocardamine was purified from the culture broth extract of strain SK5 by Mr Kojo Acquah (PhD student, Department of Chemistry, University of Cape Town). In a side-by-side spot bioautography analysis of the purified nocardamine and the strain SK5 culture broth extract, it was found that the active compound in the culture broth extract was not nocardamine, because nocardamine only had activity against M. aurum A+ while the culture broth extract had activity against M. aurum A+ and S. aureus ATCC 25923. Using the polyphasic taxonomic approach, Kribbella strain SK5 was tentatively characterised as a novel species, for which the name Kribbella stellenboschensis sp. nov. is proposed. The closest phylogenetic relatives were identified as the type strains of Kribbella aluminosa, Kribbella karoonensis, Kribbella pittospori, Kribbella shriazensis, ‘Kribbella sindirgiensis’ and ‘Kribbella soli’. Genetic distances of 0.030 and 0.016 were calculated for ‘K. soli’ and ‘Kribbella sindirgiensis’, respectively, for the concatenated gene sequence of five housekeeping genes (gyrB, rpoB, recA, relA, and atpD). Thus, DNA-DNA hybridisation (DDH) will need to be carried out to confirm that strain SK5 is a separate species. Phenotypic differences were observed between strain SK5 and all the type strains of the most closely related species. Chemotaxonomically, strain SK5 possessed the key characters definitive of the genus Kribbella: i) MK9(H4) as the major menaquinone; ii) LL-diaminopimelic acid as the diagnostic diamino acid; iii) anteiso-C15:0 and iso-C16:0 as the major fatty acids (>10%); and iv) phosphatidylcholine in the polar lipid profile.
29
Ntsaluba, Luvuyo. "Studies on bioflocculant production by a consortium of two bacterial species belonging to the Methylobacterium and Actinobacterium genera." Thesis, University of Fort Hare, 2012. http://hdl.handle.net/10353/482.
Full textAbstract:
Bioflocculants produced by two identified bacteria: Actinobacterium sp. Mayor and Methylobacterium sp. Obi were investigated with regard to their physicochemical and flocculating characteristics. The two strains were later combined to form a consortium for further studies. The optimum culture conditions for the bioflocculant production were similar for all strains except in the case of Actinobacterium sp. Mayor and the consortium, where glucose was replaced by sodium carbonate as a carbon source. Multi-nitrogen source was the best nitrogen source compare to individual sources for both strains. The divalent cation, Ca2+ proved to be a better flocculating activity stimulus for all produced bioflocculants in this study. The optimum flocculating activities obtained for both individual strains and the consortium were all at alkaline pH. The yield of purified bioflocculant produced by the consortium was 8.203 g/l, while 4.190 g/l and 4.610 g/l were recovered for single strains of Actinobacterium sp. Mayor and Methylobacterium sp. Obi respectively. Further characterization of pure bioflocculants revealed that a bioflocculant dosage of 0.3 mg/ml resulted in the highest flocculating activity for both individual strains while 1.0 mg/ml of the bioflocculant produced by the consortium was required to enhance maximum flocculating efficiency. These bioflocculants proved to be all thermo stable at a temperature range of 20 to 900°C with a heating rate of 10oC/min under a constant flow of nitrogen gas. The presence of functional groups normally required for bioflocculation such as hydroxyl, carboxyl and amino was also detected. The findings of this study suggest that the producedbioflocculants can be utilized as excellent substitutes for harmful synthetic flocculants in both water and wastewater treatments as well as in other industrial applications.
30
Barroso, Keli Cristiane Carvalho. "Interação entre Acanthamoeba polyphaga e Streptomyces sp. em um modelo de cocultivo visando a obtenção de extrato bruto com ação antimicrobiana." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/143018.
Full textAbstract:
As interações que ocorrem entre as bactérias e amebas podem dar-se através de relações mútuas, onde ambos os organismos se beneficiam da associação ou parasitárias em que um organismo se beneficia em detrimento do outro. A convivência de vários microrganismos que compartilham o mesmo ambiente pode produzir alterações seja no crescimento dos organismos, nos padrões de adaptação, na morfologia, no seu desenvolvimento, ou até mesmo na sua capacidade para sintetizar proteínas e metabólitos secundários. Neste estudo, é avaliada a interação entre Acanthamoeba polyphaga e Streptomyces sp. através de cocultivo, com objetivo de obter extratos brutos com ação antimicrobiana. No cocultivo, as amebas inviabilizaram na presença da bactéria. Após contato com as amebas houve alteração morfológica em Streptomyces sp. em todos os tempos de incubação, com produção de hifas, diferente do controle que permaneceu na fase de esporos. A partir do cocultivo foi possível obter extrato bruto em 50 dias, sendo avaliados em diferentes tempos de incubação (1º, 7º, 14º, 21º e 28º dias), contra bactérias multirresistentes como Escherichia coli e Pseudomonas aeruginosa, mostrando atividade antimicrobiana, tanto no cocultivo quanto no controle. Com análise estatística foi possível verificar que os extratos produzidos em 24 horas (1º) apresentaram maior atividade, especialmente contra P. aeruginosa. Os extratos produzidos pelo cocultivo e controle se comportaram diferentemente um do outro, porém as diferenças não foram estatisticamente significativas. Em relação à biomassa produzida, foi observado maior volume de biomassa no cocultivo, do que no controle, indicando que o contato entre os dois microrganismos favoreceu a produção de massa celular, porém não houve diferença significativa, somente quando comparado entre dias. Estes resultados mostram que há interação entre Acanthamoeba e Streptomyces uma vez que, a bactéria se beneficiou da ameba auxiliando no seu desenvolvimento. Esta interação entre os microrganismos pode ser importante na modulação da produção de substâncias de ação antimicrobiana, fato que ainda necessita investigação.The interactions that occur between bacteria and amoebas can give through mutual relations, where both organisms benefit from the association or parasitic in which one organism benefits at the expense of the other. The coexistence of various microorganisms share the same environment can produce alterations in the growth of the organisms is, patterns of adaptation in morphology, development, or even in their ability to synthesize proteins and secondary metabolites. This study evaluates the interaction between Acanthamoeba polyphaga and Streptomyces sp. through cocultivation, in order to obtain crude extracts with antimicrobial action. In cocultivation, amoebas made it impossible in the presence of the bacteria. After contact with amoebae were morphological changes in Streptomyces sp. All incubation times with hyphae production, different control spores this remained in phase. From the cocultivation it was possible to obtain crude extract in 50 days, being evaluated in different incubation times (1º, 7º, 14º, 21º and 28º days), against multiresistant bacteria such as Escherichia coli and Pseudomonas aeruginosa, showing antimicrobial activity in both the cocultivation and in control. With statistical analysis found that the extracts in 24 hours (1º) showed greater activity, especially against P. aeruginosa. The extracts produced by the coculture and control behaved differently from one another, but the differences were not statistically significant. Regarding the biomass produced, there was a higher volume of biomass in cocultivation, than in the control, indicating that the contact between the two organisms favored the cell mass production, but there was no significant difference only when compared between days. These results show that there is interaction between Acanthamoeba and Streptomyces since the bacteria benefited amoeba assisting in their development. This interaction between microorganisms may be important in modulating the production of antimicrobial substances, a fact that still requires investigation.
31
Pinheiro, Damasceno Florentino Bruno [Verfasser], and Kirsten [Akademischer Betreuer] Jung. "The translation elongation factor P in actinobacteria / Bruno Pinheiro Damasceno Florentino ; Betreuer: Kirsten Jung." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2020. http://d-nb.info/1222436736/34.
Full text
32
Everest, Gareth John. "Selective Isolation and Characterization of Indigenous Actinobacteria, with Particular Emphasis on the Genus Amycolatopsis." Doctoral thesis, University of Cape Town, 2010. http://hdl.handle.net/11427/4259.
Full text
33
Davids, Natasha. "An investigation into the enzymatic activity of deepsea actinobacteria in decolourising crystal violet dye." Master's thesis, Faculty of Engineering and the Built Environment, 2019. http://hdl.handle.net/11427/31145.
Full textAbstract:
Crystal Violet (CV) decolourising deep-sea actinobacteria could provide a great source of novel redox biocatalysts that can be used in various applications such as removal of triphenylmethane dyes from contaminated wastewater and soil, degradation of aromatic environmental pollutants, biotransformation of antimicrobial agents and degradation of xenobiotics. CV is a triphenylmethane dye that has various applications, including use in medical, research and industrial applications, but its release into the environment poses a threat to aquatic life as it has characteristics of a biocide. Only a limited number of microorganisms are able to decolourise and degrade CV, and one of these proposed mechanisms by which they do so is the catalytic effect of oxidoreductase enzymes, including peroxidases, polyphenol oxidases and laccases. Triphenylmethane reductase has also been reported to be involved in decolourising CV, but the reaction involving this enzyme has not been studied systematically. Eleven deep-sea actinobacteria were investigated and found to decolourise CV by either biodegradation or biosorption. Gordonia sp. JC 51 was selected as a candidate for further study as it could decolourise CV efficiently and could tolerate high concentrations (1mM) of CV. A combination of spectral scan studies, dye decolourisation, biodegradation assays, enzymatic assays, SDS-PAGE, Native PAGE, TLC and LC/MS/MS methods revealed the mechanism involved in the decolourisation of CV. Gordonia sp. JC 51 decolourised CV via enzymatic and non-enzymatic mechanisms. However, true decolourisation of CV was performed via biodegrading enzymes. Triphenylmethane reductase and polyphenol oxidase was confirmed to be the enzymes involved. Leucocrystal Violet was identified as the metabolite produced. CV also was sequentially N-demethylated, oxidised and cleaved into smaller compounds such as Michler’s Ketone. In conclusion, Gordonia sp. JC 51 has potential as a whole cell biocatalyst and should be investigated further.
34
King, Maria Catharina. "Bioactive actinobacteria associated with two South African medicinal plants, Aloe ferox and Sutherlandia frutescens." University of Western Cape, 2021. http://hdl.handle.net/11394/8382.
Full textAbstract:
Philosophiae Doctor - PhDActinobacteria, a Gram-positive phylum of bacteria found in both terrestrial and aquatic environments, are well-known producers of antibiotics and other bioactive compounds. The isolation of actinobacteria from unique environments has resulted in the discovery of new antibiotic compounds that can be used by the pharmaceutical industry. In this study, the fynbos biome was identified as one of these unique habitats due to its rich plant diversity that hosts over 8500 different plant species, including many medicinal plants. In this study two medicinal plants from the fynbos biome were identified as unique environments for the discovery of bioactive actinobacteria, Aloe ferox (Cape aloe) and Sutherlandia frutescens (cancer bush).
35
Aryal, Niraj [Verfasser]. "Unravelling the Chemical Diversity of Actinobacteria Obtained from Unique Asian Ecological Niches / Niraj Aryal." Tübingen : Universitätsbibliothek Tübingen, 2023. http://d-nb.info/1240673205/34.
Full text
36
Oladele, Agunbiade M. "Studies on bioflocculants produced by three freshwater Actinomycetes (Streptomyces Sp.Gansen, Cellulomonas Sp,Bola and Brachybacterium Sp, UFH) isolated from Tyume river." Thesis, University of Fort Hare, 2011. http://hdl.handle.net/10353/6550.
Full textAbstract:
Several bacteria were isolated from the bottom sediments of Tyume River and investigated for bioflocculant production potentials. Kaolin clay suspension (4 g/l) was used to measure the flocculating activity and three of the positive isolates were identified by 16S rRNA gene nucleotide sequence analyses and the sequences deposited in GenBank as Streptomyces sp Gansen (accession number HQ537129), Brachybacterium sp UFH (accession number HQ537131.), and Cellulomonas sp Bola (accession number HQ537132). Streptomyces sp Gansen exhibited its maximum flocculating activity using lactose (85% activity), peptone (76.3% activity), Ca2+ as sole sources of carbon, nitrogen and cations respectively, and at a neutral pH of 7.0, while, the bioflocculant produced by Brachybacterium sp UFH with glucose, urea and Ca2+ as carbon, nitrogen and cations sources yielded 82% and 97% flocculation activity respectively at a neutral pH. Also, glucose (73.2% activity), ammonium chloride (78.2% activity) and Ca2+ resulted in optimal production of bioflocculant by Cellulomonas sp Bola, also at a neutral pH. Chemical analysis confirmed that bioflocculant produced by Streptomyces Gansen is a polysaccharide while Brachybacterium sp UFH and Cellulomonas sp Bola produces a glycoprotein compound. This freshwater actinomycetes appears to have a tremendous potential as sou rces of new bioflocculants.
37
Salvaggio, Flavia. "Synthesis of biologically active quinolone natural products extracted from the actinomycete Pseudonocardia sp. CL38489." Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648770.
Full text
38
Omori, Wellington Pine. "Composição funcional e taxonômica de enzimas carbohidrases que atuam na desconstrução da lignocelulose de torta de filtro /." Jaboticabal, 2018. http://hdl.handle.net/11449/152891.
Full textAbstract:
Orientador: Jackson Antônio Marcondes de SouzaCoorientador: Daniel Guariz Pinheiro
Coorientador: Luciano Takeshi Kishi
Resumo: A torta de filtro apresenta bagaço residual oriundo do processo de extração do caldo de cana-de-açúcar e quando armazenada por longos períodos, se torna um habitat ideal para o desenvolvimento de comunidades microbianas que atuam na desconstrução da lignocelulose. Nossas análises de dados de sequenciamento de DNA metagenômico sugerem que a torta de filtro armazenada por 40 dias possui uma microbiota com características funcionais e ecológicas exclusivas em relação a outros ambientes com elevada disposição de material lignocelulósico. Assim como em ambientes de compostagem, os filos mais abundantes são Actinobacteria, Proteobacteria, Firmicutes e Bacteroidetes. Dentre os principais genes que estes micro-organismos possuem, estão Glicosiltransferases, Carboidrato Esterases e Glicosil Hidrolases, que atuando em conjunto, são passíveis de desconstruírem a lignocelulose e participarem na liberação de açúcares menores, ácidos orgânicos e outros nutrientes. Neste trabalho, identificamos novas enzimas da família AA10 que oxidam a celulose cristalina, demostrando o potencial deste ambiente em possibilitar a adaptação de micro-organismos que expressam enzimas capazes de desestruturar a celulose altamente condensada, possibilitando a liberação de moléculas de glicose. A comunidade microbiana pode acessar nutrientes como Fósforo e Nitrogênio através da despolimerização da biomassa vegetal ou decomposição da microbiota morta. No ciclo biogeoquímico do nitrogênio, a evaporação de amônia é ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The filter cake presents residual bagasse from the process of extracting the sugarcane juice and when stored for long periods, it becomes an ideal habitat for the development of microbial communities that act in the deconstruction of lignocellulose. Our analyzes of metagenomic DNA sequencing data suggest that the filter cake stored for 40 days has a microbiota with unique functional and ecological characteristics compared to other environments with high lignocellulosic material. Thus in composting environments, the most abundant phyla are Actinobacteria, Proteobacteria, Firmicutes, and Bacteroidetes. Glycosyltransferases, Carbohydrate Estersases and Glycoside Hydrolases, which act together, are capable of deconstructing lignocellulose and participate in the release of smaller sugars, organic acids and other nutrients. In this work, we identify new enzymes of the AA10 family that oxidize crystalline cellulose, demonstrating the potential of this environment to enable the adaptation of microorganisms that express enzymes capable of destabilizing highly condensed cellulose, allowing the release of glucose molecules. The microbial community can access nutrients such as Phosphorus and Nitrogen through the depolymerization of the plant biomass or decomposition of the dead microbiota. In the biogeochemical cycle of nitrogen, the evaporation of ammonia is reduced by the assimilation of this substance by the microbial community, and ammonia is produced by ammonification of nitrate and... (Complete abstract click electronic access below)
Doutor
39
Toyama, Danyelle. "Análise da diversidade microbiana aquática em rios e lagos da região amazônica." Universidade Federal de São Carlos, 2012. https://repositorio.ufscar.br/handle/ufscar/5501.
Full textAbstract:
Made available in DSpace on 2016-06-02T20:21:29Z (GMT). No. of bitstreams: 1
4330.pdf: 9783641 bytes, checksum: d254809e566158ecf10125a852fbdafa (MD5)
Previous issue date: 2012-11-07Financiadora de Estudos e Projetos
The Amazon region has the largest hydrographic basin on the planet, the one that includes Amazon River, and it also has the largest rainforest in the world. Moreover, it presents a great biological diversity, both related to the fauna and flora, and microbiological. Microorganisms are responsible for most biogeochemical cycles that shape the terrestrial environment and the freshwater and marine ecosystems, and they can be widely exploited biotechnologically. It is estimated that less than 1% of all bacterial species is known due to our inability to simulate the environment in which they live. However, new techniques have allowed the study of these microorganisms. Through Metagenomics it is possible to study complex environmental samples without the need for isolation and individual cultivation of these organisms. For this purpose, the16S ribosomal DNA (16S rDNA) is used in bacteria and archaea in order to study phylogeny and diversity. This sequence is used because it has been fairly maintained during the processes of biological evolution and it may serve as an indicator of how organisms are closely related. For these studies, this region was amplified by the Polymerase Chain Reaction (PCR) and cloned into vectors through the recombinant DNA technology, thus enabling the construction of 16S rRNA libraries. These libraries were then sequenced and the microorganisms were identified by comparison with databases. In this study it was used DNA extracted from Solimões River filtered water, in addition to water from other rivers and adjacent lakes, to the construction of libraries, in order to study the biodiversity through 16S rRNA analysis. In all libraries, phylum Proteobacteria was the most abundant, and most of the genera observed belong to the Betaproteobacteria class. The freshwater cosmopolitan taxa Candidatus Planktophila limnetica and Polynucleobacter were observed, as well as primary producers were represented by the genera Synechococcus and Cyanobium. Samples in which the construction of 16S rRNA libraries was possible for Archaea, the phylum Crenarchaeota was the most abundant in all libraries.
A Região Amazônica apresenta a maior bacia hidrográfica do planeta, a do rio Amazonas, e também a maior floresta tropical do mundo. Além disso, apresenta uma grande diversidade biológica, tanto relacionada à fauna e flora, quanto microbiológica. Os micro-organismos são responsáveis pela maioria dos ciclos biogeoquímicos que moldam o ambiente terrestre e os ecossistemas de água doce e marinhos, e podem ser amplamente explorados biotecnologicamente. Estima-se que menos de 1% de todas as espécies bacterianas seja conhecida, devido à incapacidade de simulação do ambiente em que vivem. Contudo, novas técnicas têm possibilitado o estudo desses micro-organismos. Através do Metagenoma é possível estudar amostras ambientais complexas sem a necessidade de isolamento e cultivo individual desses organismos. Para tanto, utiliza-se, em bactérias e arquéias, o DNA ribossomal 16S (16S rDNA), para fins de estudos de filogenia e diversidade. Esta sequência é utilizada por se ter mantido bastante conservada durante os processos de evolução biológica, podendo servir como um indicador de como os organismos estão intimamente relacionados. Para estes estudos, esta região foi amplificada pela Reação em Cadeia da Polimerase (PCR) e clonada em vetores através da tecnologia do DNA recombinante, possibilitando, assim, a construção de bibliotecas de 16S rRNA. Estas bibliotecas foram então sequenciadas e os micro-organismos identificados por comparação com bancos de dados. Neste trabalho foi utilizado DNA extraído de filtrados de água do Rio Solimões, além de outros rios e lagos adjacentes, para construção de bibliotecas, com a finalidade de estudar a biodiversidade por meio de análise do 16S rRNA. Em todas as bibliotecas o filo Proteobacteria foi o mais abundante, e a maioria dos gêneros observados pertence à classe Betaproteobacteria. Os taxa cosmopolitas de água doce Candidatus Planktophila limnetica e Polynucleobacter foram observados, assim como os produtores primários foram representados pelos gêneros Synechococcus e Cyanobium. Nas amostras em que a construção das bibliotecas de 16S rRNA foi possível para Archaea, obteve-se o filo Crenarchaeota como o mais abundante em todas as bibliotecas.
40
Minotto, Elisandra. "Caracterização de compostos produzidos por actinomicetos para o biocontrole de Bipolaris sorokiniana." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/97855.
Full textAbstract:
As actinobactérias endofíticas estão presentes nos tecidos das plantas e, por meio da produção de metabólitos ativos, às protegem e auxiliam em condições de estresse. Esses microrganismos tem sido amplamente estudados no controle de doenças fitopatogênicas, como a mancha marrom causada por Bipolaris sorokiniana. Este fungo é o agente causal da podridão comum da raiz, manchas foliares, morte de plântulas e ponto preto das sementes de trigo e cevada, causando redução significativa na produtividade. Neste contexto, os objetivos do presente estudo foram avaliar a virulência de isolados de B. sorokiniana e a atividade antifúngica de actinobactérias contra este fitopatógeno. Os antagonistas com elevada atividade contra o fitopatógeno foram caracterizados quanto à produção enzimática, fisiologia, condições de crescimento e produção de metabólitos, bem como sequenciamento do 16S rRNA para identificação dos antagonistas. A caracterização parcial dos metabólitos foi realizada por meio de sistemas de Cromatografia de Camada delgada (CCD) contendo diferentes solventes. Os resultados mostraram que os isolados de B. sorokiniana apresentaram elevada virulência às plântulas e sementes de trigo, sendo que a maior agressividade foi relatada à semente. Por outro lado, 69,6% das actinobactérias apresentaram elevada atividade antifúngica contra isolados de B. sorokiniana em meio sólido, e 17% a mantiveram em cultura submersa. A maior produção ocorreu a 30°C após 72h de incubação, para a maioria dos isolados. A detecção da produção de catalase, amilase, pectinase, lipase e esterase foi observada para a maioria das actinobactérias (100, 95,6, 91,30, 95,6, 100%, respectivamente). Enquanto que a degradação de caseína, carboximetilcelulose e gelatina foi realizada por 60,8, 34,78 e 47,82% dos isolados, respectivamente. Os isolados 6(2), 6(4), 16(3) e R18(6), selecionados devido à elevada atividade antifúngica e enzimática, apresentaram reação positiva para produção de compostos voláteis, quitinase e glucanase, sideróforos, fixação de nitrogêno, AIA e colonização de raizes. Somente isolado R18(6) não apresentou capacidade de solubilizar fosfatos. A caracterização molecular determinou que estes isolados pertencem ao gênero Streptomyces. Os metabólitos produzidos pelo isolado R18(6) foram mais estáveis a mudanças de temperatura e pH, bem como para a ação das proteases e EDTA, quando comparado aos demais. Os solventes acetato de etila e hexano foram mais eficientes na extração de metabólitos do extrato bruto, porém a melhor separação de metabólitos em CCD foi obtida com misturas de solventes.Endophitic actinobacterias are present in plant tissues and by means of active metabolites they protect and help them in stress conditions. These microorganisms have been widely used in the control of phytopathogenic diseases, such as the spot blotch caused by Bipolaris sorokiniana. This fungus is a causal agent of common root rot, leaf spots, death of seedlings and black point of the seeds of wheat and barley, causing significant reduction in productivity. In this context, the aim of this study was to evaluate the virulence of the B. sorokiniana isolates and the antifungal activity of actinobacterias against this phytopathogen. The antagonists with the higher activity against the phytopatogen were characterize taking in consideration their physiology, enzyme production, growth conditions and metabolites production and 16S rRNA sequencing for identification of the antagonists. Partial characterization (nós não purificamos) of the metabolites was performed using thin layer chromatography (TLC) systems containing different solvents. The results showed that the isolates of B. sorokiniana have a high virulence on wheat seed and seedlings, however the greater aggressiveness was observed to seed. On the other hand, 69.6% of actinomycetes showed high antifungal activity against of B. sorokiniana isolates on solid medium, and 17% maintained this behavior in submerged culture. The highest yield happened, for most isolates, when grown at 30°C with agitation after 72h of incubation. The detection of catalase, starch, pectin, lipase and esterase production was observed for most of the actinomycetes (100, 95.6, 91.30, 95.6, 100%, respectively). While the hydrolysis of casein, carboxymethylcellulase and gelatin was performed by 60.8, 34.78 and 47.82% of the isolates, respectively. Isolates 6(2), 6(4), 16(3) e R18(6), selected due to the high antifungal and enzyme activity, showed a positive reaction for the production of volatile compounds, chitinase and glucanase, siderophores, nitrogen fixation, AIA and colonization of the roots. Only the isolated R18(6) showed no ability to solubilize phosphates. Molecular characterization of the isolates determined that they belong to the genus Streptomyces. The metabolites produced by isolate R18 (6) were more stable to temperature and pH changes, as well to the action of proteases and EDTA, when compared to the others. The solvents ethyl acetate and hexane were more efficient for the extraction of the metabolites from the crude extract, however a better separation of the metabolites in the TLC was obtained with mixture of solvents.
41
Manderscheid, Niko [Verfasser], and Andriy [Akademischer Betreuer] Luzhetskyy. "Strain development for heterologous expression of secondary metabolite clusters in actinobacteria / Niko Manderscheid. Betreuer: Andriy Luzhetskyy." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2016. http://d-nb.info/108253644X/34.
Full text
42
Liu, Jing [Verfasser], and Shu-Ming [Akademischer Betreuer] Li. "Genome mining-directed discovery of novel 2,5-diketopiperazines from actinobacteria / Jing Liu ; Betreuer: Shu-Ming Li." Marburg : Philipps-Universität Marburg, 2021. http://d-nb.info/1230552634/34.
Full text
43
Du, Plessis Gerda. "Actinobacterial diversity of the Ethiopian Rift Valley lakes." University of the Western Cape, 2011. http://hdl.handle.net/11394/5385.
Full textAbstract:
>Magister Scientiae - MScThe class Actinobacteria consists of a heterogeneous group of filamentous, Gram-positive bacteria that colonise most terrestrial and aquatic environments. The industrial and biotechnological importance of the secondary metabolites produced by members of this class has propelled it into the forefront of metagenomics studies. The Ethiopian Rift Valley lakes are characterized by several physical extremes, making it a polyextremophilic environment and a possible untapped source of novel actinobacterial species. The aims of the current study were to identify and compare the eubacterial diversity between three geographically divided soda lakes within the ERV focusing on the actinobacterial subpopulation. This was done by means of a culture-dependent (classical culturing) and culture-independent (DGGE and ARDRA) approach. The results indicate that the eubacterial 16S rRNA gene libraries were similar in composition with a predominance of α-Proteobacteria and Firmicutes in all three lakes. Conversely, the actinobacterial 16S rRNA gene libraries were significantly different and could be used to distinguish between sites. The actinobacterial OTUs detected belonged to both the Rubrobacterales and Actinomycetales orders with members of the genus Arthrobacter being found in all three lakes. Geochemical properties were significantly different between the lakes, although more than one property attributed to the variance between community compositions. The diversity detected in the culture-based study differed significantly and all isolates belonged to the genus Streptomyces. Two novel strains were characterized by means of phylogenetic (16S rRNA gene sequence), physiological, morphological and biochemical analyses. Both novel isolates were capable of growing under "extreme" conditions- pH 12, 10% NaCl and 45°C. Partial enzyme characterization revealed that both strains produced xylanase enzymes that were active at pH 6.5 and 8.5 with an increase in activity up to 45°C. The results obtained revealed a previously undetected diversity of actinobacteria in the Ethiopian Rift Valley with a potentially novel subpopulation adapted to haloalkaline conditions. The low 16S rRNA sequence similarity of a substantial proportion of the libraries suggests that culture-based isolation may play a vital role in deciphering the community fingerprint.
The National Research Foundation and the Norwegian Research Council
44
Costa, Luiz Antonio Mendonça Alves da. "Reações de oxidação e hidrolise por microrganismos nos metodos de biocatalise e de biorremediação." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249096.
Full textAbstract:
Orientador: Anita Jocelyne MarsaioliTese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
Made available in DSpace on 2018-08-04T15:13:44Z (GMT). No. of bitstreams: 1 Costa_LuizAntonioMendoncaAlvesda_D.pdf: 24416441 bytes, checksum: bec02c6b51213d77af83bf869644c046 (MD5) Previous issue date: 2005
Resumo: O presente trabalho foi dividido em dois projetos: a avaliação do potencial biocatalítico de microrganismos isolados da abelha Trigonna sp e o estudo de biorremediação de ambiente contaminado por Alachlor®. A atividade catalítica de oxidação de sulfeto e a hidrólise de éster sulfínico de 12 linhagens de fungos foi avaliada durante a primeira parte deste trabalho, dentre das quais, 8 linhagens foram isoladas do corpo da abelha Trigonna sp em trabalhos anteriores do nosso grupo. Os melhores microrganismos na oxidação enantiosseletiva do etil fenil sulfeto foram os Fungo CCT 5553 e Cladosporium sp. CBMAI 0210 que produziram o (S)-etil-fenil-sulfóxido (ee > 99%) e (R)-etil-fenil-sulfóxido (ee 97%), respectivamente. O (S)-etil-fenil-sulfóxido (ee > 92%) foi aplicado na síntese da S-(+)-4-metil-3-heptanona, feromônio de alarme da formiga do gênero Atta, mas uma racemização durante a eliminação do grupo sulfinila impossibilitou a síntese total. Para a resolução enzimática de (±)-benzenossulfinato de cicloexila foi selecionado os fungos Penicillium sp. CBMAI 0208 e Aspergillus ochraceus CBMAI 0211 ambos fornecendo os produtos com excessos enantioméricos > 99%. Na segunda etapa, avaliou-se a capacidade de degradação do pesticida Alachlor® de 6 linhagens de bactérias (Streptomyces sp.) e as estruturas dos produtos de degradação foram sugeridas baseados em seus padrões de fragmentação. Entre esses 8-etil-quinolina e N-metil-8-etil-indol nunca foram citados nos estudos de biodegradação do Alachlor®.
Abstract: The work presented in this thesis is divided into two projects: the evaluation of the biocatalytic potential of microorganisms isolated from Trigonna bee and those deposited in two brazilian collections and bioremediation of Alachlor contamined soil. The sulfide oxidation and sulfinic esters hydrolysis catalytic activity was screened using 12 different fungi strains, 8 of which were previously isolated from a Trigonna sp. bee. The best microorganisms for the enantioselective oxidation of ethyl phenyl sulfide were Fungus CCT 5553 and Cladosporium sp. CBMAI 0210 WHICH PRODUCED (R)-ethyl phenyl sulfoxide (ee 97%) and (S)-ethyl phenyl sulfoxide (ee > 99%) respectively. The chiral (S)-ethyl phenyl sulfoxide which was applied in the synthesis of S-(+)-4-methyl-3-heptanone, ant alarm pheromone (genus Atta), of but racemization during sulfinyl group elimination step precluded the total asymmetric synthesis. For the enzymatic resolution of the cyclohexyl (±)-benzenosulfinate we have selected Penicillium sp. CBMAI 0208 and Aspergillus ochraceus CBMAI 0211 both with the capacity of resolving the sulfinate in over 99 enantiomeric excess. In the second part, the Alachlor® degradation potential of 6 bacterium strains (Streptomyces sp.) was evaluated and the structures of biodegradation products were suggested based on their mass fragmentation patterns. Among these 8-ethyl-quinoline and N-methyl-8-ethyl-indole have never been mentioned as Alachlor biodegradation products before.
Doutorado
Quimica Organica
Doutor em Quimica
45
Carvalho, Tiele da Silva. "Avaliação de atividade antibacteriana do actinomiceto endofítico R18(6) contra bactérias gram-negativas multirresistentes." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/108934.
Full textAbstract:
As bactérias Gram-negativas das famílias Enterobacteriaceae e Pseudomonadaceae são os patógenos mais comumente isolados de infecções. Devido ao crescente aparecimento de micro-organismos resistentes aos antimicrobianos disponíveis para terapêutica, a busca de novos compostos tornou-se eminente, principalmente oriundos de fontes naturais cultiváveis. Os actinomicetos são uma das principais fontes de metabólitos secundários com atividade antibacteriana. Este trabalho teve como objetivo avaliar o potencial do actinomiceto endofítico R18(6) em produzir metabólitos ativos contra bactérias Gram-negativas multirresistentes. Para isto, utilizou-se o teste de dupla camada para avaliar a capacidade de produção de metabólitos ativos pelo actinomiceto. As condições de cultivo, como fontes de carbono, temperatura, pH, modo de incubação e tempo de incubação do isolado, sob cultura submersa, foram otimizadas. A atividade antimicrobiana do isolado foi avaliada a cada 24 horas durante 10 dias utilizando a técnica de difusão em poço, na qual foram medidos os halos de inibição. O actinomiceto mostrou melhor atividade contra as bactérias Gram-negativas testadas quando cultivado em meio base contendo glicose como fonte de carbono, pH ajustado para 6.5, incubação a 30ºC sob agitação constante durante 96 horas. No ensaio de concentração inibitória mínima do extrato bruto, esta variou entre 1/32 e 1/256, e mostrou atividade bactericida ou bacteriostática de acordo com o isolado Gram-negativo. O extrato ativo foi avaliado quando à sua estabilidade térmica e enzimática, o qual se apresentou estável a altas temperaturas e instável às enzimas proteolíticas. O extrato bruto foi submetido à extração com solventes e a acetona mostrou-se eficiente como solvente extrator. A micromorfologia do isolado foi observada em microscopia óptica e de varredura, nos quais apresentou características semelhantes ao gênero Streptomyces. O actinomiceto endofítico R18(6) mostrou ser uma nova fonte promissora para a produção de compostos ativos contra bactérias Gram-negativas multirresistentes.Gram-negative bacteria of the Enterobacteriaceae and Pseudomonadacea family are the most common pathogens isolated from infections. Due to the increase of microorganisms resistant to antimicrobial agents available for treatment, the search for new compounds, mainly from natural and culturable sources, has become an important issue. The actinomycetes are a major source of secondary metabolites with antibacterial activity. The aim of this work was to evaluate the potential production of active metabolites by the endophytic actinomycete R18(6) against Gram-negative bacteria multiresistant. For this, the double layer method was used to assess the ability of production of active metabolites by the isolate. Based on this assay the culture condition growth of the isolate in submerged culture was optimized. For that as carbon source, temperature, pH, incubation way and incubation time were tested looking for a better metabolite production. The antimicrobial activity of the isolate was evaluated every 24 hours for 10 days by the well diffusion assay, where the inhibition halo was measured. The actinomycete showed the best activity against Gram-negative bacteria when cultured in base medium supplemented with glucose, adjusted in pH 6,5, incubation temperature of 30ºC for 96 hours with agitation. In the microdilution assay the concentration of crude extract varied from 1/32 to 1/256, and it showed bactericidal or bacteriostatic activity according to Gram-negative tested isolate. The thermal and enzymatic stability of crude extract were evaluated, where it exhibited thermal stability in high temperature and it was unstable to proteolytic enzymes. The crude extract was subjected to solvent extraction and acetone was efficient as extractor solvent. The isolate showed similar characteristics of the genus Streptomyces when evaluated by optical and scanning microscopy. The endophytic actinomycete R18(6) showed to be a new and a promising source of active metabolites production against Gram-negative bacteria multidrug resistant.
46
Borba, Marcela Proença. "Caracterização de isolados de actinobactérias utilizando BOX-PCR e URP-PCR e purificação de composto bioativo produzido por um isolado de Streptomyces sp." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/143012.
Full textAbstract:
O filo Actinobacteria é um importante grupo de bactérias Gram positivas amplamente distribuídas nos ambientes aquáticos e terrestres, são grandes produtores de compostos biologicamente ativos e, portanto, de grande interesse biotecnológico. O gênero Streptomyces destaca-se como maior produtor destes compostos, sendo responsável por cerca de 70% dos antibióticos que hoje utilizamos. A identificação dos organismos deste gênero ainda é um desafio. Durante muitos anos a identificação foi realizada somente com base em características morfológicas e fisiológicas. Atualmente, com o avanço das técnicas moleculares, há um grande número de espécies relatadas em bancos de dados genômicos. Este trabalho tem por objetivo identificar isolados de actinobactérias presentes no Laboratório de Microbiologia Ambiental ICBS/UFRGS com auxílio das técnicas de BOX-PCR, amplamente utilizado em estudos de diversidade dentro deste filo, e URP-PCR. E, além disso, realizar purificação parcial de um composto antimicrobiano efetivo contra bactérias produzido pelo isolado Streptomyces 8S. Os primers URP e BOX1AR produziram distintos padrões de amplificação nos isolados estudados, porém não foi possível investigar as relações de similaridade entre eles. Ainda o sequenciamento da região 16S rDNA não foi eficiente para identificar as espécies. Para a purificação do composto antimicrobiano foi realizada extração líquido-líquido com o solvente acetato de etila, posteriormente cromatografia de gel-filtração (Sephadex G-75) e troca iônica (SP-Sepharose e DEAE-celulose). A atividade antimicrobiana do composto foi recuperada após cada etapa. O composto manteve-se ativo após os ensaios de estabilidade frente à adição de EDTA, enzimas proteolíticas e altas temperaturas. Isto sugere que o composto antimicrobiano não é de origem protéica. Este trabalho sugere novos estudos a partir dos resultados preliminares obtidos, como a amplificação de todo o fragmento 16S rDNA dos isolados de actinobactérias e a investigação do composto antimicrobiano através de cromatografias de alta resolução.The Actinobacteria phylum is an important group of Gram positive bacteria widely distributed in terrestrial and aquatic environments. They are major producers of biologically active compounds and therefore of great biotechnological interest. The genus Streptomyces stands out as the largest producer of these compounds, accounting for about 70% of the antibiotics that we use today. The identification of these organisms is still a challenge. For many years the identification was carried out only based on morphological and physiology characteristics. Today, with the advance of molecular techniques, there are a large number of species reported in genomics database. This work aims to identify isolates of actinobacterias present in the Laboratório de Microbiologia Ambiental ICBS / UFRGS with the help of BOX-PCR techniques, widely used in diversity studies within this phylum, and URP-PCR. And besides that, performing partial purification of an antimicrobial compound effective against bacteria produced by Streptomyces 8S isolated. The URP and BOX1AR primers produced different amplification patterns in the isolates, but it was not possible to investigate the relationship of similarity between them. Also the sequencing of 16S rDNA was not efficient to identify the species. To purify the antimicrobial compound was carried out liquid-liquid extraction with the solvent ethyl acetate, subsequently chromatography: gel-filtration (Sephadex G-75) and ion exchange (SP-Sepharose and DEAE-cellulose). The antimicrobial in question did not adhere to the SP-Sepharose column, showing that it has negative charge. The antimicrobial activity of the compound was recovered after each step. The compound remained active after the stability tests like the addition of EDTA, proteolytic enzymes and high temperatures. This suggests that the antimicrobial compound is not a protein. This work suggests further studies based on the obtained preliminary results such as the amplification of the entire 16S rDNA of actinobacterias isolated fragment and the investigation of the antimicrobial compound using high resolution chromatography.
47
Pereira, Priscila Monteiro. "Avaliação da atividade antifúngica sobre Bipolaris sorokiniana e promoção de crescimento em plantas de trigo de isolados de Streptomyces sp." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/165282.
Full textAbstract:
Os isolados Streptomyces sp. R18(6) e 6(4) foram avaliados quanto à sua capacidade de controlar a mancha marrom e podridão comum de raiz, causados por Bipolaris sorokiniana em plantas de trigo. A atividade antifúngica desses isolados foi testada usando os ensaios de dupla camada e pareamento de cultura à 28°C. A atividade fisiológica e enzimática foi avaliada através de ensaios de sideróforo, ácido indol-3-acético, fixação de nitrogênio e solubilização de fosfato. O controle biológico da doença e a eficiência de crescimento das plantas de trigo foram avaliados utilizando ensaios in vivo em casa de vegetação. Nos ensaios de pareamento de cultura, ambos os isolados inibiram o crescimento micelial de B. sorokiniana, enquanto na dupla camada apenas o isolado R18(6) inibiu. Streptomyces sp. 6(4) produziu auxina, sideróforos, fixou nitrogênio e solubilizou fosfato, enquanto R18(6) não produziu sideróforos. Nos ensaios em casa de vegetação, o isolado R18(6) mostrou diferenças estatísticas na massa seca da parte aérea e na massa seca de raiz em comparação com a do isolado 6(4) na presença do fitopatógeno (P≤0,05). Estes resultados foram mais evidentes quando a temperatura foi maior. Na ausência do fitopatógeno, o isolado 6(4) aumentou a massa seca de raiz em comparação com a do controle durante o mesmo período. Portanto, esses isolados apresentaram potencial em controlar a podridão das raízes e mancha marrom e podem promover o crescimento das plantas de trigo.Streptomyces sp. R18(6) and 6(4) strains were evaluated for their ability to control brown spot and common root rot caused by Bipolaris sorokiniana in wheat crops. The antifungal activity of these isolates was tested using a doublelayer assay and culture pairing at 28 °C. Physiological and enzymatic activity were evaluated through siderophore, indole-3-acetic acid, nitrogen fixation and phosphate solubilization assays. The biocontrol of the disease and growthpromoting efficiency of wheat seedlings were assessed using in vivo assays in greenhouse. In the culture pairing assays, both strains inhibited B. sorokiniana mycelial growth, while in the double-layer only R18(6). Streptomyces sp. 6(4) produced auxin, siderophores, fixed nitrogen and solubilized phosphate, whereas R18(6) did not produce siderophores. In the greenhouse assays, strain R18 (6) showed statistical differences in shoot dry mass and root dry mass compared with those of strain 6(4) in the presence of the phytopathogen (P ≤ 0.05). These results were more evident when the temperature was higher. In the absence of the phytopathogen, strain 6(4) increased the root dry mass compared with that of the control during the same period. Therefore, these isolates can potentially control root rot and brown spotting and may promote the growth of wheat plants.
48
Salem, Shaimaa Mohamed. "Biosynthesis of Marineosin, a Spiroaminal Undecylprodiginine Natural Product." PDXScholar, 2012. https://pdxscholar.library.pdx.edu/open_access_etds/936.
Full textAbstract:
Marineosins A and B are two spiroaminal-ring containing tripyrrole compounds isolated from the marine actinomycete, Streptomyces CNQ-617, and were found to possess potent and selective cytotoxic activity against leukemia and melanoma. Marineosins belong to the prodiginines class of natural products, examples of which are undecylprodiginine and streptorubin B. Unlike marineosins, prodiginines structures are characterized by the presence of fully conjugated tripyrrole nucleus linked to an alkyl chain (that lacks any oxygen). Cyclic prodiginines arise from an oxidative cyclization of the alkyl chain onto the tripyrrole, a step catalyzed by Rieske-oxygenase like enzymes such as RedG. The biosynthesis of prodiginines is directed via the red gene cluster. The unique structural differences between marineosin and other prodiginines spurred the proposal of a number of hypotheses for its biosynthesis, none of which have been experimentally tested. A red gene cluster homolog which has only one extra dehydratase-encoding gene; marA has been identified from the genomic library of Streptomyces CNQ-617, and the identified cluster was proposed to direct the biosynthesis of marineosin. In this study, the identified putative gene cluster was expressed in the heterologous host, S. venezuelae, and marineosin production in the new strain; JND2 was confirmed via LC/MS and 1H-NMR. The new engineered strain also produces a myriad of marineosin related shunt metabolites and pathway intermediates. This study hence presents the first identified gene cluster proved to direct the biosynthesis of marineosin; the mar gene cluster and proves that the cloned cluster encodes most, if not all the enzymes required to direct the biosynthesis of marineosin. Deletion of the Rieske-oxygenase encoding gene; marG (a RedG homolog) from the mar gene cluster led to the accumulation of 2-hydroxyundecylprodiginine; G410 with an m/z 410.28 and molecular formula C25H35O2N3. This data proves that MarG is not responsible for the introduction of the spiromaminal ring oxygen on the alkyl chain, but is required for catalyzing macrocyclic ring formation between C-8 and C-9 of G410. Undecylprodiginine production in marG deletion mutant was not observed which indicates that undecylprodiginine is likely not an intermediate along the pathway for marineosin biosynthesis, and indicates that the spiroaminal ring oxygen is introduced early in the pathway, possibly due to the incorporation of a 3-hydroxy-butyric acid starter unit. Deletion of the dehydratase-encoding gene; marA, from the mar gene cluster led to the accumulation of compounds JN408 and JN422 with m/z 408.26 and 422.24 and molecular formulae C25H33O2N3, and C25H31O3N3, respectively. Purification and structure elucidation of JN408 proves it to be an oxidized marineosin analog which has fully aromatic tripyrrole rings while; purification and structure elucidation of JN422 proves it to be a 9-keto-JN408 derivative. Both JN408 and JN422 compounds have a spiroaminal ring which indicates that MarA does not catalyze spiroaminal ring formation but catalyzes the reduction of pyrrole ring B of JN408 to yield marineosin. Therefore, we are proposing that MarA acts as a dehydrogenase, rather than a dehydratase. We are proposing that the intramolecular spiroaminal ring formation is catalyzed by either MarG or occurs non-enzymatically. JN422 is a shunt metabolite produced due to promiscuous activity of either MarG or an unidentified oxidase in the mar cluster, possibly MarT. From the data generated in this study, we present the first experimentally supported pathway for the biosynthesis of marineosin and the opportunity to generate novel compounds with potentially useful biological activities.
49
Landwehr, Wiebke Verfasser], and Joachim Manfred [Akademischer Betreuer] [Wink. "Isolation and characterization from novel actinobacteria and myxobacteria especially from marine habitats / Wiebke Landwehr ; Betreuer: Joachim M. Wink." Braunschweig : Technische Universität Braunschweig, 2017. http://d-nb.info/1175817252/34.
Full text
50
Landwehr, Wiebke Verfasser], and Joachim [Akademischer Betreuer] [Wink. "Isolation and characterization from novel actinobacteria and myxobacteria especially from marine habitats / Wiebke Landwehr ; Betreuer: Joachim M. Wink." Braunschweig : Technische Universität Braunschweig, 2017. http://nbn-resolving.de/urn:nbn:de:gbv:084-2017071911011.
Full text