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Letteratura scientifica selezionata sul tema "Bacterial secondary metabolites"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 6 febbraio 2022

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Articoli di riviste sul tema "Bacterial secondary metabolites"

Andryukov, Boris, Valery Mikhailov e Nataly Besednova. "The Biotechnological Potential of Secondary Metabolites from Marine Bacteria". Journal of Marine Science and Engineering 7, n. 6 (3 giugno 2019): 176. http://dx.doi.org/10.3390/jmse7060176.

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Marine habitats are a rich source of molecules of biological interest. In particular, marine bacteria attract attention with their ability to synthesize structurally diverse classes of bioactive secondary metabolites with high biotechnological potential. The last decades were marked by numerous discoveries of biomolecules of bacterial symbionts, which have long been considered metabolites of marine animals. Many compounds isolated from marine bacteria are unique in their structure and biological activity. Their study has made a significant contribution to the discovery and production of new natural antimicrobial agents. Identifying the mechanisms and potential of this type of metabolite production in marine bacteria has become one of the noteworthy trends in modern biotechnology. This path has become not only one of the most promising approaches to the development of new antibiotics, but also a potential target for controlling the viability of pathogenic bacteria.

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Shibl, Ahmed A., Ashley Isaac, Michael A. Ochsenkühn, Anny Cárdenas, Cong Fei, Gregory Behringer, Marc Arnoux et al. "Diatom modulation of select bacteria through use of two unique secondary metabolites". Proceedings of the National Academy of Sciences 117, n. 44 (16 ottobre 2020): 27445–55. http://dx.doi.org/10.1073/pnas.2012088117.

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Unicellular eukaryotic phytoplankton, such as diatoms, rely on microbial communities for survival despite lacking specialized compartments to house microbiomes (e.g., animal gut). Microbial communities have been widely shown to benefit from diatom excretions that accumulate within the microenvironment surrounding phytoplankton cells, known as the phycosphere. However, mechanisms that enable diatoms and other unicellular eukaryotes to nurture specific microbiomes by fostering beneficial bacteria and repelling harmful ones are mostly unknown. We hypothesized that diatom exudates may tune microbial communities and employed an integrated multiomics approach using the ubiquitous diatomAsterionellopsis glacialisto reveal how it modulates its naturally associated bacteria. We show thatA. glacialisreprograms its transcriptional and metabolic profiles in response to bacteria to secrete a suite of central metabolites and two unusual secondary metabolites, rosmarinic acid and azelaic acid. While central metabolites are utilized by potential bacterial symbionts and opportunists alike, rosmarinic acid promotes attachment of beneficial bacteria to the diatom and simultaneously suppresses the attachment of opportunists. Similarly, azelaic acid enhances growth of beneficial bacteria while simultaneously inhibiting growth of opportunistic ones. We further show that the bacterial response to azelaic acid is numerically rare but globally distributed in the world’s oceans and taxonomically restricted to a handful of bacterial genera. Our results demonstrate the innate ability of an important unicellular eukaryotic group to modulate select bacteria in their microbial consortia, similar to higher eukaryotes, using unique secondary metabolites that regulate bacterial growth and behavior inversely across different bacterial populations.

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Nofiani, Risa, Alexandra J. Weisberg, Takeshi Tsunoda, Ruqiah Ganda Putri Panjaitan, Ridho Brilliantoro, Jeff H. Chang, Benjamin Philmus e Taifo Mahmud. "Antibacterial Potential of Secondary Metabolites from Indonesian Marine Bacterial Symbionts". International Journal of Microbiology 2020 (29 giugno 2020): 1–11. http://dx.doi.org/10.1155/2020/8898631.

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Indonesian http://mts.hindawi.com/update/) in our Manuscript Tracking System and after you have logged in click on the ORCID link at the top of the page. This link will take you to the ORCID website where you will be able to create an account for yourself. Once you have done so, your new ORCID will be saved in our Manuscript Tracking System automatically."?>marine environments are known to house diverse organisms. However, the potential for bacteria from these environments as a source of antibacterial agents has not been widely studied. This study aims to explore the antibacterial potential of secondary metabolites produced by bacterial symbionts from sponges and corals collected in the Indonesian waters. Extracts of 12 bacterial isolates from sponges or corals were prepared by cultivating the bacteria under a number of different media conditions and using agar well diffusion assays to test for antibacterial activity. In addition, the morphology, physiology, and biochemical characteristics and 16S rRNA sequence of each isolate were used to determine their taxonomic classification. All tested bacterial isolates were able to produce secondary metabolites with various levels of antibacterial activity depending on medium composition and culture conditions. Two of the bacteria (RS3 and RC4) showed strong antibacterial activities against both Gram-negative and Gram-positive bacteria. A number of isolates (RS1, RS3, and RC2) were co-cultured with mycolic acid-containing bacteria, Mycobacterium smegmatis or Rhodococcus sp. However, no improvements in their antibacterial activity were observed. All of the 12 bacteria tested were identified as Streptomyces spp. LC-MS analysis of EtOAc extracts from the most active strains RS3 and RC4 revealed the presence of a number of dactinomycin analogues and potentially new secondary metabolites. Symbiotic Streptomyces spp. from sponges and corals of the Indonesian marine environments have great potential as a source of broad-spectrum antibacterial agents.

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de Felício, Rafael, Patricia Ballone, Cristina Freitas Bazzano, Luiz F. G. Alves, Renata Sigrist, Gina Polo Infante, Henrique Niero et al. "Chemical Elicitors Induce Rare Bioactive Secondary Metabolites in Deep-Sea Bacteria under Laboratory Conditions". Metabolites 11, n. 2 (12 febbraio 2021): 107. http://dx.doi.org/10.3390/metabo11020107.

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Bacterial genome sequencing has revealed a vast number of novel biosynthetic gene clusters (BGC) with potential to produce bioactive natural products. However, the biosynthesis of secondary metabolites by bacteria is often silenced under laboratory conditions, limiting the controlled expression of natural products. Here we describe an integrated methodology for the construction and screening of an elicited and pre-fractionated library of marine bacteria. In this pilot study, chemical elicitors were evaluated to mimic the natural environment and to induce the expression of cryptic BGCs in deep-sea bacteria. By integrating high-resolution untargeted metabolomics with cheminformatics analyses, it was possible to visualize, mine, identify and map the chemical and biological space of the elicited bacterial metabolites. The results show that elicited bacterial metabolites correspond to ~45% of the compounds produced under laboratory conditions. In addition, the elicited chemical space is novel (~70% of the elicited compounds) or concentrated in the chemical space of drugs. Fractionation of the crude extracts further evidenced minor compounds (~90% of the collection) and the detection of biological activity. This pilot work pinpoints strategies for constructing and evaluating chemically diverse bacterial natural product libraries towards the identification of novel bacterial metabolites in natural product-based drug discovery pipelines.

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You, Chuan, Dan Qin, Yumeng Wang, Wenyi Lan, Yehong Li, Baohong Yu, Yajun Peng, Jieru Xu e Jinyan Dong. "Plant Triterpenoids Regulate Endophyte Community to Promote Medicinal Plant Schisandra sphenanthera Growth and Metabolites Accumulation". Journal of Fungi 7, n. 10 (23 settembre 2021): 788. http://dx.doi.org/10.3390/jof7100788.

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Beneficial interactions between endophytes and plants are critical for plant growth and metabolite accumulation. Nevertheless, the secondary metabolites controlling the feedback between the host plant and the endophytic microbial community remain elusive in medicinal plants. In this report, we demonstrate that plant-derived triterpenoids predominantly promote the growth of endophytic bacteria and fungi, which in turn promote host plant growth and secondary metabolite productions. From culturable bacterial and fungal microbial strains isolated from the medicinal plant Schisandra sphenanthera, through triterpenoid-mediated screens, we constructed six synthetic communities (SynComs). By using a binary interaction method in plates, we revealed that triterpenoid-promoted bacterial and fungal strains (TPB and TPF) played more positive roles in the microbial community. The functional screening of representative strains suggested that TPB and TPF provide more beneficial abilities to the host. Moreover, pot experiments in a sterilized system further demonstrated that TPB and TPF play important roles in host growth and metabolite accumulation. In summary, these experiments revealed a role of triterpenoids in endophytic microbiome assembly and indicated a strategy for constructing SynComs on the basis of the screening of secondary metabolites, in which bacteria and fungi join forces to promote plant health. These findings may open new avenues towards the breeding of high yielding and high metabolite-accumulating medicinal plants by exploiting their interaction with beneficial endophytes.

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Lee, Jong Suk, Yong-Sook Kim, Sooyeon Park, Jihoon Kim, So-Jung Kang, Mi-Hwa Lee, Sangryeol Ryu, Jong Myoung Choi, Tae-Kwang Oh e Jung-Hoon Yoon. "Exceptional Production of both Prodigiosin and Cycloprodigiosin as Major Metabolic Constituents by a Novel Marine Bacterium, Zooshikella rubidus S1-1". Applied and Environmental Microbiology 77, n. 14 (3 giugno 2011): 4967–73. http://dx.doi.org/10.1128/aem.01986-10.

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ABSTRACTA Gram-negative, red-pigment-producing marine bacterial strain, designated S1-1, was isolated from the tidal flat sediment of the Yellow Sea, Korea. On the basis of phenotypic, phylogenetic, and genetic data, strain S1-1 (KCTC 11448BP) represented a new species of the genusZooshikella. Thus, we propose the nameZooshikella rubidussp. nov. Liquid chromatography and mass spectrometry of the red pigments produced by strain S1-1 revealed that the major metabolic compounds were prodigiosin and cycloprodigiosin. In addition, this organism produced six minor prodigiosin analogues, including two new structures that were previously unknown. To our knowledge, this is the first description of a microorganism that simultaneously produces prodigiosin and cycloprodigiosin as two major metabolites. Both prodigiosin and cycloprodigiosin showed antimicrobial activity against several microbial species. These bacteria were approximately 1.5-fold more sensitive to cycloprodigiosin than to prodigiosin. The metabolites also showed anticancer activity against human melanoma cells, which showed significantly more sensitivity to prodigiosin than to cycloprodigiosin. The secondary metabolite profiles of strain S1-1 and two reference bacterial strains were compared by liquid chromatography-mass spectrometry. Multivariate statistical analyses based on secondary metabolite profiles by liquid chromatography-mass spectrometry indicated that the metabolite profile of strain S1-1 could clearly be distinguished from those of two phylogenetically related, prodigiosin-producing bacterial strains.

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Melo, Flávia Mandolesi Pereira de, Marli Fátima Fiore, Luiz Alberto Beraldo de Moraes, Maria Estela Silva-Stenico, Shirlei Scramin, Manoel de Araújo Teixeira e Itamar Soares de Melo. "Antifungal compound produced by the cassava endophyte Bacillus pumilus MAIIIM4a". Scientia Agricola 66, n. 5 (ottobre 2009): 583–92. http://dx.doi.org/10.1590/s0103-90162009000500002.

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In the search for new organisms and new secondary metabolites, a study was conducted to evaluate the diversity of endophytic bacteria from ethnovarieties of cassava cultivated by Brazilian Amazon Indian tribes and also to study the secondary metabolites produced by a Bacillus pumilus strain. Sixty seven cassava endophytic bacteria were subjected to 16S rRNA sequencing and FAME analysis. The bacterial profile revealed that 25% of all endophytic isolates belonged to the genus Bacillus. The isolate B. pumilus MAIIIM4a showed a strong inhibitory activity against the fungi Rhizoctonia solani, Pythium aphanidermatum and Sclerotium rolfsii. Secondary metabolites of this strain were extracted using hexane, dichloromethane and ethyl acetate. Extracts were subjected to bioautography and LC/MS analysis, which allowed the identification of pumilacidin, an antifungal compound produced by B. pumilus MAIIIM4a. The bacterial endophytic localization was confirmed by cassava cell tissue examination using scanning electron microscopy.

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Apriyola, Nadya, Feliatra Feliatra e Yuana Nurulita. "SECONDARY METABOLITE CHARACTERISTIC OF HETEROTROPHIC BACTERIA PRODUCTION AS ANTIMICROBIA AT DIFFERENT SALINITY". Asian Journal of Aquatic Sciences 3, n. 2 (4 agosto 2020): 147–57. http://dx.doi.org/10.31258/ajoas.3.2.147-157.

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This research was conducted from March-June 2019. The purpose of this study was to determine the characteristics of secondary metabolites prduced by of heterotrophic bacterial from sea water Sungai Kayu Ara Village, Siak Regency as an antimicrobial and to determine the storage time of these bacteria by measuring at the optimal growth time. Five bacterial secondary metabolite extracts used were B, C, D, and H (B. cereus) and J (V. fluvialis) obtained from the collection of Marine Microbiology Laboratory, Department of Marine Sciences, Faculty of Fisheries and Marine sciences, University of Riau. phytochemical test showed that extracts of isolates B, D, and H contained saponin compounds, while isolate J contained flavonoid compounds, however, all extracts contained alkaloid compounds. Antimicrobial test indicated that J extract inhibited A. Hydrophila at concentration 500 µg/ml but the extract could not inhibit V. algynolyticus and Pseudomonas sp concentrations determined. In the bacterial storage time test, the optimal growth of each bacterial concentration at was 7th day incubation and decreased on the 14th day.

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Hiruma, Kei. "Roles of Plant-Derived Secondary Metabolites during Interactions with Pathogenic and Beneficial Microbes under Conditions of Environmental Stress". Microorganisms 7, n. 9 (18 settembre 2019): 362. http://dx.doi.org/10.3390/microorganisms7090362.

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Under natural conditions, plants generate a vast array of secondary metabolites. Several of these accumulate at widely varying levels in the same plant species and are reportedly critical for plant adaptation to abiotic and/or biotic stresses. Some secondary metabolite pathways are required for beneficial interactions with bacterial and fungal microbes and are also regulated by host nutrient availability so that beneficial interactions are enforced. These observations suggest an interplay between host nutrient pathways and the regulation of secondary metabolites that establish beneficial interactions with microbes. In this review, I introduce the roles of tryptophan-derived and phenylpropanoid secondary-metabolite pathways during plant interactions with pathogenic and beneficial microbes and describe how these pathways are regulated by nutrient availability.

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Caroline, J. Kosgei, Tolo Festus, C. Matasyoh Josphat, Obonyo Meshack, Mwitari Peter, Keter Lucia, Korir Richard e Irungu Beatrice. "Anti-bacterial activity of secondary metabolites from Chrysanthemum cinerariaefolium". Journal of Medicinal Plants Research 15, n. 6 (30 giugno 2021): 241–51. http://dx.doi.org/10.5897/jmpr2019.6888.

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Più fonti

Tesi sul tema "Bacterial secondary metabolites"

Egan, Suhelen Microbiology &amp Immunology UNSW. "Production and regulation of fouling inhibitory compounds by the marine bacterium Pseudoalteromonas tunicata". Awarded by:University of New South Wales. Microbiology and Immunology, 2001. http://handle.unsw.edu.au/1959.4/17838.

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The marine surface-associated bacterium Pseudoaltermonas tunicata, produces a range of compounds that inhibit fouling organisms, including invertebrate larvae, bacteria, algal spores and fungi. In addition to these antifouling compounds P. tunicata cells produce both a yellow and a purple pigment. The aim of this study was to further characterise the antifouling activities, their regulation and relationship with pigmentation, and the ecological significance of P. tunicata and related organisms. It was discovered that the anti-algal compound was extracellular, heat sensitive, polar and between 3 and 10 kDa in size. The anti-fungal compound was found to be the yellow pigment and active against a wide range of fungal and yeast isolates. Chemical analysis suggests that this compound consists of a carbon ring bound to a fatty-acid side chain. Genetic analysis supports the chemical data for the active compound as a mutant in a gene encoding for a long-chain fatty-acid CoA ligase was deficient for anti-fungal activity. To address the regulation of antifouling compounds and their relationship to pigmentation transposon mutagenesis of P. tunicata was performed. Mutants lacking the yellow pigment displayed a reduced ability to inhibit fouling organisms. Further analysis of these mutants identified genes involved with the synthesis and regulation of synthesis of pigment and antifouling compounds. One of these mutants was disrupted in a gene (wmpR) with similarity to the transcriptional regulators ToxR from Vibrio cholerae and CadC from Escherichia coli. Analysis of global protein expression using two-dimensional gel electrophoresis showed that WmpR is essential for the expression of at least fifteen proteins important for the synthesis of fouling inhibitors. The ecological significance of antifouling bacteria was addressed by assessing the antifouling capabilities of a collection of bacteria isolated from different marine surfaces. Overall, isolates from living surfaces displayed more antifouling traits then strains isolated from non-living surfaces. Five dark-pigmented strains originating from the alga Ulva lactuca were further studied. Phylogenetic and phenotypic analysis revealed that they were all members of the genus Pseudoalteromonas and were closely related to P. tunicata. Two strains represented a novel species within the genus and were taxonomically defined as P. ulvae sp. nov.

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Nguyen, Thi Bach Le. "Discovery of active secondary metabolites from Paenibacillus odorifer, a lichen-associated bacterium". Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1S098/document.

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Les bactéries qui sont des sources prolifiques d'antibiotiques et des fournisseurs importants d’agents pharmaceutiques peuvent produire une grande variété de métabolites. Ainsi, la découverte de métabolites issus bactéries est un nouveau challenge pour les chimistes. Parmi ces sources, les lichens sont admis comme niches intéressantes de nouvelles bactéries et de nouveaux composés bactériens. Par conséquent, les communautés de micro-organismes associées aux lichens sont devenues des sources prometteuses pour la production de composés naturels actifs. Dans cette thèse, nous avons concentré notre travail sur l'isolement des bactéries de Rhizocarpon geogaphicum, l'un des lichens crustacés les plus populaires vivant sur la roche. Parmi les souches isolées, Paenibacillus odorifer a été sélectionnée pour poursuivre les travaux visant à produire des composés actifs. Après des étapes d’optimisation de culture, l’étude des extraits issus des cultures de P. odorifer soit par le bioréacteur soit en Erlenmeyer a permis l’isolement des métabolites : un polysaccharide antioxydant, deux dérivés tert-butylphénoliques cytotoxiques issus de la bioaccumulation et de la biotransformation de précurseurs, d'un nouvel alcaloïde cytotoxique, de deux diols, de deux dérivés de type furfural et quelques autres composés connus. Des hypothèses de biosynthèse ont pu être proposés pour certains composés. La diversité des métabolites isolés de P. odorifer indique que cette espèce possède un grand potentiel de production des composés actifs et est une bactérie utilisatrice de substrats tert-butyl phénoliques
Bacteria which are prolific sources of antibiotics and important suppliers to the pharmaceutical agents can produce a wide variety of metabolites. Thus finding metabolites from the bacterial lineages represented new interests for chemists. Among that, lichens are admitted as a rich source of new bacterial lineages and novel bacterial compounds. Therefore, microorganism communities associated with lichens became significant subjects as great potential for the production of active natural compounds. In this thesis, we focus our work on the isolation of bacterial lineages from the lichen Rhizocarpon geographicum, one of the most popular crustose lichens dwelling on the rock. Among the strains isolated, Paenibacillus odorifer was selected for further work to produce active compounds. After the culture optimization steps, the study of extracts from the P. odorifer cultures either in the bioreactor or in Erlenmeyer flask led to the production of metabolites: an antioxidant polysaccharide, two cytotoxic tert-butylphenol derivatives which came from the bioaccumulation and biotransformation of precursors, a novel and cytotoxic alkaloid compound, two diol compounds, two furfural derivatives and some other known compounds. Putative biosynthetic pathways have been proposed for some compounds. The diversity of metabolites isolated from P. odorifer highlighted that this species possessed a great potential of the production active compounds and were a new case of tert-butyl phenol utilizing bacterium

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Liu, Shuai [Verfasser]. "Bioactive Secondary Metabolites from Marine-Derived Fungi and Exploration of Fungal-Bacterial Co-Cultivation / Shuai Liu". Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2016. http://d-nb.info/1122263600/34.

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Walmsley, Tara Aisling. "An investigation into the bacterial diversity associated with South African latrunculid sponges that produce bioactive secondary metabolites". Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1012943.

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Algoa Bay Latrunculid sponges are well known for their production of cytotoxic pyrroloiminoquinones with speculation that these secondary metabolites may have a microbial origin. This study describes a thorough investigation into the bacterial community associated with Tsitsikamma favus, Tsitsikamma scurra a newly described Latrunculia sp. and a yellow encrusting sponge associated with T. scurra. Molecular and chemical characterisation were used in conjunction with traditional taxonomy in identification of the sponge specimens. The 28S rRNA and COX1 analysis confirmed the traditional taxonomy with T. favus and T. scurra being very closely related. Chemical analysis revealed that T. favus and T. scurra shared the discorhabdins 2,4-debromo-3-dihydrodiscorhabdin C, 7,8-dehydro-3-dihydrodiscorhabdin C and 14-bromo-1-hydroxy-discorhabdin V in common with each other and Tsitsikamma pedunculata indicating that these pyrroloiminoquinones are common to Tsitsikamma sponges in general. The bacterial community associated with T. favus was explored using 16S rRNA molecular techniques including DGGE, clonal libraries of full length 16S rRNA genes, as well as 454 pyrosequencing. DGGE analysis revealed that the bacterial community associated with T. favus appeared to be highly conserved, which was confirmed by both the clone library and 454 pyrosequencing, with the Betaproteobacteria as the most dominant class. Further exploration into T. favus, as well as T. scurra, Latrunculia sp. and the yellow encrusting sponge indicated that the bacterial populations associated with each of these sponge species were conserved and species specific. OTU analysis to the species level revealed that T. favus and T. scurra shared an abundant Spirochaete species in common while the most abundant species in the Latrunculia sp. and the yellow encrusting sponge belonged to the class Betaproteobacteria. The exclusivity of the tsitsikammamines to T. favus precipitated attempts to culture the T. favus associated bacteria, with a focus on the dominant betaproteobacterium as indicated by the 16S rRNA clone library. Actinobacteria associated with the Algoa Bay sponge specimens were also cultured and the actinobacterial isolates were sent for screening against Mycobacterium aurum with two Kocuria kristinae isolates and a Streptomyces albdioflavus isolate showing good antimycobacterial activity.

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Gerard, Jeffery M. "Antibiotic secondary metabolites of bacteria isolated from the marine environment". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq25055.pdf.

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Hassiotis, Christos N. "Effects of plant secondary metabolites on bacteria and fungi populations". Thesis, University of Reading, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387705.

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Sweidan, Alaa. "Antibiofilm activity of lichen secondary metabolites". Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1B017/document.

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Les bactéries buccales n'infectent pas seulement la bouche mais y resident. Elles peuvent également passer dans la voie sanguine et atteindre des organes secondaires. S’il n'est pas traité, le biofilm dentaire peut provoquer une inflammation destructrice dans la cavité buccale, entrainant de graves complications médicales. Dans ce biofilm, Streptococcus gordonii, colonisateur oral primaire, constitue la plate-forme sur laquelle des colonisateurs pathogènes tardifs comme Porphyromonas gingivalis, l'agent causal des maladies parodontales, se lieront. L'objectif de la première partie de la thèse était de déterminer l'activité antibactérienne de onze composés de lichens appartenant à différentes familles chimiques, pour découvrir de nouveaux antibiotiques pouvant combattre ces bactéries buccales. Nous avons montré que trois composés avaient des activités antibactériennes prometteuses. L'acide psoromique enregistrait les CMIs le plus faibles. De nouveaux analogues de butyrolactone ont ensuite été conçus et synthétisés sur la base des composés antibactériens licheniques connus, les acides lichesteriniques, en substituant différents groupes fonctionnels sur le cycle butyrolactone pour améliorer son activité sur S. gordonii et P. gingivalis. Parmi les dérivés, B-12 et B-13 avaient la plus faible CMI où ils se sont révélés être des bactéricides plus forts, 2 à 3 fois plus, que l'antibiotique, doxycycline. B-12 et B-13 étaient également les plus efficaces vis-à-vis de P. gingivalis. La cytotoxicité de ces 2 composés a ensuite été vérifiée contre les cellulaires épithéliales gingivales humaines et les macrophages. Ils ne présentaient pas de toxicité contre les cellules testées. Une étude préliminaire de relation structure-activité a révélé le double rôle important apporté par deux substituants, chaîne alkyle en C5 et groupe carboxyle en C4 positions, dans leur mécanisme d'action. Ceci a été suivi par l'étude de l’activité antibiofilmique de B-12 et B-13 contre les deux souches orales en utilisant un test de cristal violet et microscopie confocale. Les deux dérivés ont montré, à une concentration plus faible, une inhibition maximale de la formation du biofilm, LCMI, de 9.38 μg/mL contre S. gordonii et 1.17 μg/mL contre P. gingivalis. Cependant, lorsque des concentrations sous-inhibitrices de B-12 et B-13 ont été utilisées, nous avons démontré que les deux souches étudiées pouvaient former des biofilms in vitro, accompagné d’une diminution de l'expression des gènes impliqués dans l'adhésion et la formation de biofilm. Pour mieux comprendre les mécanismes d'action des butyrolactones, nous avons étudié la localisation bactérienne du composé B-13 en synthétisant un B-13 marqué au NBD (4-nitro-benzo [1,2,5] oxadiazole) fluorescent conservant son activité antibactérienne. Par microscopie confocale et HPLC, nous avons montré que ce composé se lie à la surface cellulaire de S. gordonii. Ensuite, B-13 induit une rupture de la paroi cellulaire conduisant à la libération des constituants bactériens et par conséquent, à la mort de S. gordonii, une bactérie Gram-positive. L'expression de deux gènes, murA et alr, impliqués dans la synthèse de la paroi cellulaire, a été modifiée en présence de cette butyrolactone. Les bactéries Gram négatives telles que P. gingivalis ont également montré des cellules abimées présentant une rupture de la paroi en présence de B-13, ce qui suggère que cette butyrolactone agit sur des Gram-positives et Gram-négatives avec une plus grande efficacité contre les Gram-négatives. En outre, nous avons également démontré que l'analogue de B-13, B-12, induit une perturbation de la morphologie de P. gingivalis et S. gordonii. Toutes ces études ont démontré que les butyrolactones dérivées de lichen peuvent être proposés comme des composés antibactériens puissants contre les agents pathogènes oraux qui causent des complications médicales graves
The oral bacteria do not only infect the mouth and reside there, but also travel via the blood and reach distant body organs. If left untreated, the dental biofilm that can cause destructive inflammation in the oral cavity may result in serious systemic medical complications. In dental biofilm, Streptococcus gordonii, a primary oral colonizer, constitutes the platform on which late pathogenic colonizers like Porphyromonas gingivalis, the causative agent of periodontal diseases, will bind. The aim of the first study was to determine the antibacterial activity of eleven natural lichen compounds belonging to different chemical families to uncover new antibiotics which can fight against the oral bacteria. Three compounds were shown to have promising antibacterial activities where psoromic acid had the lowest MICs of 11.72 and 5.86 µg/mL against S. gordonii and P. gingivalis, respectively. Novel butyrolactone analogues were then designed and synthesized based on the known lichen antibacterial compounds, lichesterinic acids (B-10 and B-11), by substituting different functional groups on the butyrolactone ring trying to enhance its activity on S. gordonii and P. gingivalis.. Among the derivatives, B-12 and B-13 had the lowest MIC of 9.38 µg/mL where they have shown to be stronger bactericidals, by 2-3 times, than the reference antibiotic, doxycycline. B-12 and B-13 were also the most efficient on P. gingivalis exhibiting MIC of 0.037 and 0.293 µg/mL and MBC of 1.17 and 0.586 µg/mL, respectively. These 2 compounds were then checked for their cytotoxicity against human gingival epithelial cells and macrophages by MTT and LDH assays which confirmed their safety against the tested cell lines. A preliminary study of the structure-activity relationships unveiled the important dual role contributed by two substituents, alkyl chain at C4 and carboxyl group at C5 positions, in their mechanism of action. This was followed by the investigation of B-12 and B-13 for their antibiofilm activity against both oral strains using crystal violet assay and confocal microscopy. Both derivatives displayed a lowest concentration with maximal biofilm inhibition, LCMI, of 9.38 µg/mL against S. gordonii and 1.17 µg/mL against P. gingivalis. However, when sub-inhibitory concentrations of B-12 and B-13 were used, we demonstrated that the two investigated strains were able to form biofilms in vitro. Indeed, this antibiofilm activity decreased as indicated by the expression of the genes implicated in adhesion and biofilm formation. To better understand the mechanism of action of butyrolactones, we have investigated B-13 bacterial localization by synthesizing a fluorescently labeled B-13 with NBD (4-nitro-benzo[1,2,5]oxadiazole) conserving its antibacterial activity. By confocal microscope, we showed that this compound binds to S. gordonii cell surface and this was also demonstrated by HPLC analysis. By adhering to cell surface, B-13 induced cell wall disruption leading to the release of bacterial constituents and consequently, the death of S. gordonii, a Gram-positive bacterium. The expression of two genes, murA and alr, implicated in cell wall synthesis, was modified in the presence of this butyrolactone. Gram-negative bacteria such as P. gingivalis showed also cracked and ruptured cells in the presence of B-13, suggesting that this butyrolactone acts on Gram-positive and Gram-negative strains, but with greater efficacy against the Gram-negatives. Besides, we also demonstrated that the analogue of B-13, B-12, has also induced disruption of P. gingivalis and S. gordonii. All these studies demonstrated that butyrolactones derived from a lichen metabolite can be proposed as potent antibacterial agents against oral pathogens causing serious medical complications

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Tesmar, Alexander von [Verfasser], e Rolf [Akademischer Betreuer] Müller. "Investigation of bacterial secondary metabolite pathways / Alexander von Tesmar ; Betreuer: Rolf Müller". Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2017. http://d-nb.info/1194371817/34.

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Gontang, Erin Ann. "Phylogenetic diversity of gram-positive bacteria and their secondary metabolite genes". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2008. http://wwwlib.umi.com/cr/ucsd/fullcit?p3324374.

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Abstract (sommario):

Thesis (Ph. D.)--University of California, San Diego, 2008.
Title from first page of PDF file (viewed October 3, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.

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Matobole, Relebohile Matthew. "Matrix comparison of isolation conditions for secondary metabolite producing marine sponge associated bacteria". University of the Western Cape, 2015. http://hdl.handle.net/11394/4754.

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>Magister Scientiae - MSc
The discovery of novel secondary metabolites has declined significantly in recent years whereas there is a rise in the number of multi-drug resistant pathogens and other types of diseases. The decline in natural product discovery was due to high rediscovery of already known compounds and the costs in developing natural products. As a result pharmaceutical companies lost interest in investing in natural product discovery. However, there is a renewed interest in marine sponge associated microorganisms as a rich and untapped source of secondary metabolites. The objective of this study was to design a matrix to investigate the extent to which the One Strain-Many Compounds (OSMAC) approach applies to a collection of marine sponge isolates harvested from two South African marine sponge samples. Terminal restriction fragment length polymorphisms (T-RFLP) analysis was used to investigate and ascertain the two marine sponges which hosted the highest microbial diversities to be used for further culture-dependent studies. The culture-dependent studies, using 33 media which included liquid enrichment, heat treatments and antibiotic treatments, resulted in 400 sponge isolates from the two marine sponges Isodictya compressa and Higginsia bidentifera. Using antibacterial overlay assays, 31 dereplicated isolates showed antibacterial activity. Bioactivities were also exhibited against E. coli 1699 which is genetically engineered for resistance against 52 antibiotics which implies that some of the bioactive compounds could be novel. The 16S rRNA gene sequences revealed that the microbial phyla isolated from the marine sponges belonged to Actinobacteria, Firmicutes and Proteobacteria (Alphaproteobacteria and Gammaproteobacteria).Thirty isolates were selected for an OSMAC-based matrix study, 17 of which showed noantibacterial activities in preliminary screening. The application of the OSMAC approach using co-culture and 36 culture conditions resulted in 6 isolates showing antibacterial activities, three of which did not show activities in preliminary screening. One of these, a Bacillus pumilus isolated from I. compressa displayed antibacterial activity against 5 indicator strains whereas in preliminary screening it had not shown activity. The results show that marine sponges can host novel microbial species which may produce novel bioactive compounds. The results also confirm that traditional methods employing a single culture condition restricts the expression of some biosynthetic pathways of microorganisms and as a result many metabolites have yet to be identified.

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Capitoli di libri sul tema "Bacterial secondary metabolites"

Ida, Idayu Muhamad, Pa’E Norhayati e Azly Zahan Khairul. "Chapter 5 Bacterial Cellulose as Secondary Metabolite: Production, Processing, and Applications". In Plant Secondary Metabolites, 169–200. 3333 Mistwell Crescent, Oakville, ON L6L 0A2, Canada: Apple Academic Press, 2016. http://dx.doi.org/10.1201/9781315366326-6.

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Velusamy, P., e S. S. Gnanamanickam. "The Effect of Bacterial Secondary Metabolites on Bacterial and Fungal Pathogens of Rice". In Secondary Metabolites in Soil Ecology, 93–106. Berlin, Heidelberg: Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-74543-3_5.

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Mathivanan, N., V. R. Prabavathy e V. R. Vijayanandraj. "The Effect of Fungal Secondary Metabolites on Bacterial and Fungal Pathogens". In Secondary Metabolites in Soil Ecology, 129–40. Berlin, Heidelberg: Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-74543-3_7.

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Ida, Idayu, Pa’E Norhayati e Azly Khairul. "Chapter 5 Bacterial Cellulose as Secondary Metabolite: Production, Processing, and Applications". In Plant Secondary Metabolites, 3 Volume Set, 169–200. 3333 Mistwell Crescent, Oakville, ON L6L 0A2, Canada: Apple Academic Press, 2016. http://dx.doi.org/10.1201/9781315207506-6.

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Mohammadipanah, Fatemeh, e Maryam Zamanzadeh. "Bacterial Mechanisms Promoting the Tolerance to Drought Stress in Plants". In Secondary Metabolites of Plant Growth Promoting Rhizomicroorganisms, 185–224. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-5862-3_10.

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Hutchinson, C. Richard, Heinrich Decker, Pat Guilfoile, Ben Shen, Richard Summers, Evelyn Wendt-Pienkowski e Bill Wessel. "Polyketide Synthases: Enzyme Complexes and Multifunctional Proteins Directing the Biosynthesis of Bacterial Metabolites from Fatty Acids". In Secondary-Metabolite Biosynthesis and Metabolism, 3–10. Boston, MA: Springer US, 1992. http://dx.doi.org/10.1007/978-1-4615-3012-1_1.

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Caldeira, Ana Teresa. "Green Mitigation Strategy for Cultural Heritage Using Bacterial Biocides". In Microorganisms in the Deterioration and Preservation of Cultural Heritage, 137–54. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-69411-1_6.

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AbstractThe microbiota present in cultural heritage objects, made by diverse inorganic and organic materials and inserted into particular environment, represents a complex and dynamic ecosystem composed by bacteria, cyanobacteria, fungi, algae and lichens, which can induce decay by biological mechanisms. To control the microbial growth several methods are being applied such as mechanical and physical processes and chemical biocides. However, these methods have several weaknesses like be dangerous to handle, material incompatibility or produce environmental and health hazards. Therefore, the identification of effectively biodeteriogenic agents and the design of mitigation strategies directed to these agents without prejudice to historical materials, to the environment and to operators, taking into account the microbial community’s dynamics, is an important challenge to control biodeterioration of cultural heritage. Bacteria, in particular Bacillus spp. are worth for the creation of new green biocides solutions because they produce a great variety of secondary metabolites including ribosomally and non-ribosomally synthesized antimicrobial peptides, known to possess antagonistic activities against many biodeteriogenic fungi and bacteria. The discovery of new safe active compounds and green nanotechnology for direct application in cultural heritage safeguard can in a close future contribute to potentiate a new generation of biocides and safe sustainable methods for cultural heritage.

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Surette, Michael G., e Julian Davies. "A New Look at Secondary Metabolites". In Chemical Communication among Bacteria, 307–22. Washington, DC, USA: ASM Press, 2014. http://dx.doi.org/10.1128/9781555815578.ch19.

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Mazzoli, Roberto, e Enrica Pessione. "Ancient Textile Deterioration and Restoration: Bio-Cleaning of an Egyptian Shroud Held in the Torino Museum". In Microorganisms in the Deterioration and Preservation of Cultural Heritage, 199–216. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-69411-1_9.

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AbstractAncient textiles are fragile and several factors can affect their integrity. In the present chapter, the main agents of deterioration of old and new textiles, namely physical-chemical (light, oxygen, heat, and humidity) and biological factors as well as human erroneous interventions will be explored. As far as the biological deterioration is considered, the effects of microbial growth, primary and secondary metabolites (acids, solvents, surfactants, pigments) and enzymes (lipases, proteases, and glycosidases) on textile strength and cleanliness will be described in details. The main fungal and bacterial species involved in the damage (textile discoloration, black and green spots, cuts) will be reported. Adhesive application during restoration procedures is discussed to highlight the risk of glue thickening giving rise to dull precipitates on the fabric.The main strategies for oil-stain and glue removal (both animal glue, such as fish collagen, and vegetal glue, i.e. starch) will be described in the paragraph devoted to biorestoration. Finally, a case study concerning an ancient Coptic tunic housed in the Egyptian Museum of Torino, Italy, and biocleaned by means of gellan-immobilized alpha-amylase from Bacillus sp. will be largely discussed by reporting historical data, adhesive characterization, methods for artificial aging of simulated sample and glue removal from the artwork.

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Sansinenea, Estibaliz. "Bacillus spp.: As Plant Growth-Promoting Bacteria". In Secondary Metabolites of Plant Growth Promoting Rhizomicroorganisms, 225–37. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-5862-3_11.

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Atti di convegni sul tema "Bacterial secondary metabolites"

Pratama, Mohammad, e Isna Aziz. "Molecular Docking of Bawang Dayak (Eleutherine bulbosa) Secondary Metabolites as Bacterial Cell Wall Synthesis Inhibitor". In 1st International Conference on Science and Technology, ICOST 2019, 2-3 May, Makassar, Indonesia. EAI, 2019. http://dx.doi.org/10.4108/eai.2-5-2019.2284686.

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Khair, Nedaa Kamalalden. "Activity of Antibiotic Producing Bacteria Isolated from Rhizosphere Soil Region of Different Medicinal Plants". In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0093.

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The rhizosphere soil of medicinal plants is rich in microorganisms that develop antibiotics as natural mechanism of protection against other microbes that live in their vicinity. The present study aims to explore the production of antibacterial agents from rhizosphere soil bacteria of 11 medicinal plants and determine their activity against Gram-negative (Pseudomonas aeruginosa, Escherichia coli) and Gram-positive (Bacillus cereus, Staphylococcus aureus) bacteria. Soil samples were collected and used to isolate antibiotic producing bacteria (APB). Those isolates (108) were first tested using Cross-streak method against test bacteria. Then, isolates that showed a positive antibacterial effect (12) were tested by antibiotic susceptibility test (AST) of their cell free supernatant (CFS) and their extracellular and intracellular secondary metabolites extraction which gave positive results. Staphylococcus aureus found to be the most sensitive test bacteria with inhibitory zones ranging from 13.5 - 19 mm. Moreover, combinatorial effect of isolates CFS with two organic acids (3% Acetic acid and 0.4 mg/ml Acetylsalicylic acid), two commercial antibiotics (0.016 mg/ml Augmentin and 0.128 mg/ml Doxycycline), and two pure antibiotics (10 mcg/disk Penicillin and 25mcg/disk Carbenicillin) was in vitro evaluated using AST. The combinations of CFS-carbenicillin showed a marked synergistic activity against all test bacteria. The presence of possible antibacterial agents as acetic acid, lactic acid and citric acid in CFS of APB was confirmed by HPLC analysis. Ultimately, in vitro antibacterial study for rhizosphere soil bacteria in this work suggests the possibility of using these bacterial metabolites in clinical infections caused by selected test bacteria, especially when they combine with antibiotics or organic acids.

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Anugrah, Fauzi Akhbar, Satrio Anggoro Putra, Sulisetijono Sulisetijono, Sitoresmi Prabaningtyas e Hanumi Oktyani Rusdi. "Screening of secondary metabolites quinine alkaloid by endophytic bacteria from cinchona plants (Cinchona ledgeriana moens.) root". In INTERNATIONAL CONFERENCE ON LIFE SCIENCES AND TECHNOLOGY (ICoLiST 2020). AIP Publishing, 2021. http://dx.doi.org/10.1063/5.0052924.

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O'Brien, ER, E. Read, M. Deyholos e L. Nelson. "Effects of Nitric oxide Producing Bacteria Azospirillum brasilense on Microbial Composition and Secondary Metabolite Profile of Cannabis". In Abstracts of the NHPRS – The 15th Annual Meeting of the Natural Health Products Research Society of Canada (NHPRS). Georg Thieme Verlag KG, 2018. http://dx.doi.org/10.1055/s-0038-1644915.

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Rosa, Marcos P., Jose V. C. Vargas, Vanessa M. Kava, Fernando G. Dias, Daiani Savi, Beatriz Santos, Wellington Balmant, Andre B. Mariano, Andre Servienski e Juan C. Ordóñez. "Hydrogen and Compounds With Biological Activity From Microalgae". In ASME 2019 13th International Conference on Energy Sustainability collocated with the ASME 2019 Heat Transfer Summer Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/es2019-3965.

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Abstract Microalgae have a high biotechnological potential as a source of biofuels (biodiesel, biohydrogen) and other high-added value products (e.g., pharmaceuticals, proteins, pigments). However, for microalgae cultivation to be economically competitive with other fuel sources, it is necessary to apply the concept of biorefinery. This seems to be the most ambitious strategy to achieve viability. Therefore, the objectives of this study were to isolate and identify the main microalgae line used to produce biofuels at Federal University of Parana, Brazil, using the rDNA sequence and micromorphological analysis, and to evaluate the potential of this lineage in the production of hydrogen and co-products with biological activity. For the purification of the lineage (LGMM0001), an aliquot was seeded into solid CHU culture medium and an isolated colony was selected. The genomic DNA was purified using a commercial kit (Macherey-Nagel, Düren, Germany) for molecular identification, the ITS region (ITS1, 5.8S and ITS2) (Internal Transcribed Spacer) was amplified and sequenced using primers LS266 and V9G. Morphological characterization was performed as described by Hemschemeier et al. [1]. Finally, for biological activity research, secondary metabolites were extracted by fractionation and evaluated against bacteria of clinical interest. Through microscopic analysis, general characteristics shared by the genus Tetradesmus were observed. The plasticity of the morphological characteristics of this genus reinforces the need for further studies to classify correctly the species in this group, using DNA sequencing. ITS sequence analysis of LGMM0001 showed 100% homology with sequences from the Tetradesmus obliquus species, so, the lineage was classified as belonging to this species. The evaluated microalgae strain was able to produce hydrogen, showing positive results for gas formation. Biological activity was observed with the extract obtained from the residual culture carried out with alternative medium used in the photobioreactors (PBR), against the Staphylococcus aureus pathogenic lineage. In conclusion, the microalgae strain used in this work was identified as Tetradesmus obliquus (= Acutodesmus obliquus), and was able to produce a compound with economic potential in association with the existing biofuel production process.

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