Articoli di riviste: "Bacterial secondary metabolites"

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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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Chen, Dawei, Lingyun Jia, Qinzheng Hou, Xiang Zhao e Kun Sun. "Analysis of Endophyte Diversity of Rheum palmatum from Different Production Areas in Gansu Province of China and the Association with Secondary Metabolite". Microorganisms 9, n. 5 (30 aprile 2021): 978. http://dx.doi.org/10.3390/microorganisms9050978.

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Investigations of the differences in the metabolites of medicinal plants have typically focused on the effects of external environmental factors. However, little is known about the relationship between endophytes diversity and host metabolites. We used high-throughput sequencing methods to compare the endophyte diversity of Rheum palmatum from eight different production areas in Gansu Province of China and to analyze the association between those areas and five secondary metabolites (aloe-emodin, rhein, emodin, chrysophanol, and physcion). The results show that the diversity and OTUs (Operational taxonomic units) abundance of endophytic fungi and bacteria of R. palmatum differed according to production area. Spearman analysis showed that the five secondary metabolites of R. palmatum were positively correlated with the diversity and abundance of endophytic fungi. Comparing both space and environmental differences to determine influences on community structure, VPA analysis revealed that geographic factors explained more difference in community composition of fungal and bacterial endophytes than climate factors. PICRUSt and FUNGuild predictive analysis indicated that metabolites were the primary components of endophytic bacteria in all samples, while the function of endophytic fungi was composed of dominant trophic modes (saprotroph and pathotroph), and relative abundances were different. Our results help elucidate the correlation of plant–microbe interactions and offer pivotal information to reveal the role of endophytes in the production of R. palmatum and its important secondary metabolite.

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Hamer, Henrike M., Vicky De Preter, Karen Windey e Kristin Verbeke. "Functional analysis of colonic bacterial metabolism: relevant to health?" American Journal of Physiology-Gastrointestinal and Liver Physiology 302, n. 1 (gennaio 2012): G1—G9. http://dx.doi.org/10.1152/ajpgi.00048.2011.

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With the use of molecular techniques, numerous studies have evaluated the composition of the intestinal microbiota in health and disease. However, it is of major interest to supplement this with a functional analysis of the microbiota. In this review, the different approaches that have been used to characterize microbial metabolites, yielding information on the functional end products of microbial metabolism, have been summarized. To analyze colonic microbial metabolites, the most conventional way is by application of a hypothesis-driven targeted approach, through quantification of selected metabolites from carbohydrate (e.g., short-chain fatty acids) and protein fermentation (e.g., p-cresol, phenol, ammonia, or H2S), secondary bile acids, or colonic enzymes. The application of stable isotope-labeled substrates can provide an elegant solution to study these metabolic pathways in vivo. On the other hand, a top-down approach can be followed by applying metabolite fingerprinting techniques based on 1H-NMR or mass spectrometric analysis. Quantification of known metabolites and characterization of metabolite patterns in urine, breath, plasma, and fecal samples can reveal new pathways and give insight into physiological regulatory processes of the colonic microbiota. In addition, specific metabolic profiles can function as a diagnostic tool for the identification of several gastrointestinal diseases, such as ulcerative colitis and Crohn's disease. Nevertheless, future research will have to evaluate the relevance of associations between metabolites and different disease states.

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Rajan, Pethannan Raja, Malla Sudhakar, Bhaskar Bhaskar, Anubroto Gosh e Sachin Karmakar. "MOLECULAR EVALUATION OF ANTISTAPHYLOCOCCAL SECONDARY METABOLITES OF BACTERIAL ISOLATES FROM HOSPITAL WASTEWATER ENVIRONMENT". Asian Journal of Pharmaceutical and Clinical Research 10, n. 6 (1 giugno 2017): 317. http://dx.doi.org/10.22159/ajpcr.2017.v10i6.17560.

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Objective: Antibiotics revolutionized medicine in the 20th century, and have together with vaccination led to the near eradication of diseases such as tuberculosis in the developed world. Their effectiveness and easy access led to overuse, especially in livestock raising, prompting bacteria to develop resistance. The lantibiotics form a particular group among the antimicrobial peptides and are characterized by unique structural features. They are produced by a group of bacteria against some gram-positive bacteria. The present study was designed to screen for the lantibiotic producing organisms from the hospital samples.Methods: The bacterial isolates were identified based on Bergey’s manual of bacteriology and screened for the epidermin gene by polymerase chain reaction amplification.Results: Of the 21 isolates screened, only 10 of them showed positive amplification for the epigene. Based on the biochemical characteristics, the isolates obtained were identified and labeled.Conclusion: Further study on the purification of the compound need to be done. Some bacterial samples may not have the epidermin gene which does not show amplification, this confers that the epidermin gene is absent in certain organisms.

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Solecka, Jolanta, Joanna Zajko, Magdalena Postek e Aleksandra Rajnisz. "Biologically active secondary metabolites from Actinomycetes". Open Life Sciences 7, n. 3 (1 giugno 2012): 373–90. http://dx.doi.org/10.2478/s11535-012-0036-1.

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AbstractSecondary metabolites obtained from Actinomycetales provide a potential source of many novel compounds with antibacterial, antitumour, antifungal, antiviral, antiparasitic and other properties. The majority of these compounds are widely used as medicines for combating multidrug-resistant Gram-positive and Gram-negative bacterial strains. Members of the genus Streptomyces are profile producers of previously-known secondary metabolites. Actinomycetes have been isolated from terrestrial soils, from the rhizospheres of plant roots, and recently from marine sediments. This review demonstrates the diversity of secondary metabolites produced by actinomycete strains with respect to their chemical structure, biological activity and origin. On the basis of this diversity, this review concludes that the discovery of new bioactive compounds will continue to pose a great challenge for scientists.

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Xu, Lin, Kai-Xiong Ye, Wen-Hua Dai, Cong Sun, Lian-Hua Xu e Bing-Nan Han. "Comparative Genomic Insights into Secondary Metabolism Biosynthetic Gene Cluster Distributions of Marine Streptomyces". Marine Drugs 17, n. 9 (26 agosto 2019): 498. http://dx.doi.org/10.3390/md17090498.

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Bacterial secondary metabolites have huge application potential in multiple industries. Biosynthesis of bacterial secondary metabolites are commonly encoded in a set of genes that are organized in the secondary metabolism biosynthetic gene clusters (SMBGCs). The development of genome sequencing technology facilitates mining bacterial SMBGCs. Marine Streptomyces is a valuable resource of bacterial secondary metabolites. In this study, 87 marine Streptomyces genomes were obtained and carried out into comparative genomic analysis, which revealed their high genetic diversity due to pan-genomes owning 123,302 orthologous clusters. Phylogenomic analysis indicated that the majority of Marine Streptomyces were classified into three clades named Clade I, II, and III, containing 23, 38, and 22 strains, respectively. Genomic annotations revealed that SMBGCs in the genomes of marine Streptomyces ranged from 16 to 84. Statistical analysis pointed out that phylotypes and ecotypes were both associated with SMBGCs distribution patterns. The Clade I and marine sediment-derived Streptomyces harbored more specific SMBGCs, which consisted of several common ones; whereas the Clade II and marine invertebrate-derived Streptomyces have more SMBGCs, acting as more plentiful resources for mining secondary metabolites. This study is beneficial for broadening our knowledge about SMBGC distribution patterns in marine Streptomyces and developing their secondary metabolites in the future.

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Kelly, SR, E. Garo, PR Jensen, W. Fenical e JR Pawlik. "Effects of Caribbean sponge secondary metabolites on bacterial surface colonization". Aquatic Microbial Ecology 40 (2005): 191–203. http://dx.doi.org/10.3354/ame040191.

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Díaz-Pérez, Alma L., César Díaz-Pérez e Jesús Campos-García. "Bacterial l-leucine catabolism as a source of secondary metabolites". Reviews in Environmental Science and Bio/Technology 15, n. 1 (31 ottobre 2015): 1–29. http://dx.doi.org/10.1007/s11157-015-9385-3.

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Thapa, Sudarshan Singh, e Anne Grove. "Do Global Regulators Hold the Key to Production of Bacterial Secondary Metabolites?" Antibiotics 8, n. 4 (23 settembre 2019): 160. http://dx.doi.org/10.3390/antibiotics8040160.

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The emergence of multiple antibiotic resistant bacteria has pushed the available pool of antibiotics to the brink. Bacterial secondary metabolites have long been a valuable resource in the development of antibiotics, and the genus Burkholderia has recently emerged as a source of novel compounds with antibacterial, antifungal, and anti-cancer activities. Genome mining has contributed to the identification of biosynthetic gene clusters, which encode enzymes that are responsible for synthesis of such secondary metabolites. Unfortunately, these large gene clusters generally remain silent or cryptic under normal laboratory settings, which creates a hurdle in identification and isolation of these compounds. Various strategies, such as changes in growth conditions and antibiotic stress, have been applied to elicit the expression of these cryptic gene clusters. Although a number of compounds have been isolated from different Burkholderia species, the mechanisms by which the corresponding gene clusters are regulated remain poorly understood. This review summarizes the activity of well characterized secondary metabolites from Burkholderia species and the role of local regulators in their synthesis, and it highlights recent evidence for the role of global regulators in controlling production of secondary metabolites. We suggest that targeting global regulators holds great promise for the awakening of cryptic gene clusters and for developing better strategies for discovery of novel antibiotics.

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Jensen, Paul R., Philip G. Williams, Dong-Chan Oh, Lisa Zeigler e William Fenical. "Species-Specific Secondary Metabolite Production in Marine Actinomycetes of the Genus Salinispora". Applied and Environmental Microbiology 73, n. 4 (8 dicembre 2006): 1146–52. http://dx.doi.org/10.1128/aem.01891-06.

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ABSTRACT Here we report associations between secondary metabolite production and phylogenetically distinct but closely related marine actinomycete species belonging to the genus Salinispora. The pattern emerged in a study that included global collection sites, and it indicates that secondary metabolite production can be a species-specific, phenotypic trait associated with broadly distributed bacterial populations. Associations between actinomycete phylotype and chemotype revealed an effective, diversity-based approach to natural product discovery that contradicts the conventional wisdom that secondary metabolite production is strain specific. The structural diversity of the metabolites observed, coupled with gene probing and phylogenetic analyses, implicates lateral gene transfer as a source of the biosynthetic genes responsible for compound production. These results conform to a model of selection-driven pathway fixation occurring subsequent to gene acquisition and provide a rare example in which demonstrable physiological traits have been correlated to the fine-scale phylogenetic architecture of an environmental bacterial community.

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Peters, Lars, Gabriele M. KÃ¯Â¿Â½nig, Anthony D. Wright, RÃ¯Â¿Â½diger Pukall, Erko Stackebrandt, Leo Eberl e Kathrin Riedel. "Secondary Metabolites of Flustra foliacea and Their Influence on Bacteria". Applied and Environmental Microbiology 69, n. 6 (giugno 2003): 3469–75. http://dx.doi.org/10.1128/aem.69.6.3469-3475.2003.

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ABSTRACT The North Sea bryozoan Flustra foliacea was investigated to determine its secondary metabolite content. Gas chromatography-mass spectrometry analysis of a dichloromethane extract of the bryozoan enabled 11 compounds to be identified. Preparative high-performance liquid chromatography of the extract resulted in the isolation of 10 brominated alkaloids (compounds 1 to 10) and one diterpene (compound 11). All of these compounds were tested to determine their activities in agar diffusion assays against bacteria derived from marine and terrestrial environments. Compounds 1, 3 to 7, 10, and 11 exhibited significant activities against one or more marine bacterial strains originally isolated from F. foliacea but only weak activities against all of the terrestrial bacteria. By using the biosensors Pseudomonas putida(pKR-C12), P. putida(pAS-C8), and Escherichia coli(pSB403) the antagonistic effect on N-acyl-homoserine lactone-dependent quorum-sensing systems was investigated. Compounds 8 and 10 caused reductions in the signal intensities in these bioassays ranging from 50 to 20% at a concentration of 20 μg/ml.

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Teasdale, Margaret E., Jiayuan Liu, Joselynn Wallace, Fatemeh Akhlaghi e David C. Rowley. "Secondary Metabolites Produced by the Marine Bacterium Halobacillus salinus That Inhibit Quorum Sensing-Controlled Phenotypes in Gram-Negative Bacteria". Applied and Environmental Microbiology 75, n. 3 (5 dicembre 2008): 567–72. http://dx.doi.org/10.1128/aem.00632-08.

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ABSTRACT Certain bacteria use cell-to-cell chemical communication to coordinate community-wide phenotypic expression, including swarming motility, antibiotic biosynthesis, and biofilm production. Here we present a marine gram-positive bacterium that secretes secondary metabolites capable of quenching quorum sensing-controlled behaviors in several gram-negative reporter strains. Isolate C42, a Halobacillus salinus strain obtained from a sea grass sample, inhibits bioluminescence production by Vibrio harveyi in cocultivation experiments. With the use of bioassay-guided fractionation, two phenethylamide metabolites were identified as the active agents. The compounds additionally inhibit quorum sensing-regulated violacein biosynthesis by Chromobacterium violaceum CV026 and green fluorescent protein production by Escherichia coli JB525. Bacterial growth was unaffected at concentrations below 200 μg/ml. Evidence is presented that these nontoxic metabolites may act as antagonists of bacterial quorum sensing by competing with N-acyl homoserine lactones for receptor binding.

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Srinivasan, Ramanathan, Arunachalam Kannappan, Chunlei Shi e Xiangmin Lin. "Marine Bacterial Secondary Metabolites: A Treasure House for Structurally Unique and Effective Antimicrobial Compounds". Marine Drugs 19, n. 10 (23 settembre 2021): 530. http://dx.doi.org/10.3390/md19100530.

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The prevalence of antimicrobial resistance reduces the effectiveness of antimicrobial drugs in preventing and treating infectious diseases caused by pathogenic organisms, such as bacteria, fungi, and viruses. Because of the burgeoning growth of microbes with antimicrobial-resistant traits, there is a dire need to identify and develop novel and effective antimicrobial agents to treat infections from antimicrobial-resistant strains. The marine environment is rich in ecological biodiversity and can be regarded as an untapped resource for prospecting novel bioactive compounds. Therefore, exploring the marine environment for antimicrobial agents plays a significant role in drug development and biomedical research. Several earlier scientific investigations have proven that bacterial diversity in the marine environment represents an emerging source of structurally unique and novel antimicrobial agents. There are several reports on marine bacterial secondary metabolites, and many are pharmacologically significant and have enormous promise for developing effective antimicrobial drugs to combat microbial infections in drug-resistant pathogens. In this review, we attempt to summarize published articles from the last twenty-five years (1996–2020) on antimicrobial secondary metabolites from marine bacteria evolved in marine environments, such as marine sediment, water, fauna, and flora.

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Onwuka, F., F. Orji, R. Uzeh e E. Ugoji. "Properties of Bacterial Cellulases and Secondary Metabolites of Cellulolytic Bacterial Fermentation of Rice Husks". Asian Journal of Biotechnology and Bioresource Technology 2, n. 1 (10 gennaio 2017): 1–11. http://dx.doi.org/10.9734/ajb2t/2017/35196.

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Makuwa, Sephokoane Cindy, e Mahloro Hope Serepa-Dlamini. "The Antibacterial Activity of Crude Extracts of Secondary Metabolites from Bacterial Endophytes Associated with Dicoma anomala". International Journal of Microbiology 2021 (12 aprile 2021): 1–12. http://dx.doi.org/10.1155/2021/8812043.

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Endophytic bacteria isolated from medicinal plants are recognized valuable sources of novel bioactive compounds with various activities such as antimicrobial, anticancer, and antiviral. In this study, eleven bacterial endophytes were isolated from surface sterilized roots and leave tissues, of medicinal plant Dicoma anomala. The bacterial endophytes were identified by sequencing the 16S rRNA gene, and belong to five genera viz Bacillus, Staphylococcus, Stenotrophomonas, Enterobacter, and Pantoea. The dominant genera were Bacillus with five strains, Staphylococcus with two strains, and Stenotrophomonas with two strains. The crude extracts of seven selected bacterial endophytes indicated antimicrobial activity against five pathogenic strains Escherichia coli (ATCC 25922), Bacillus cereus (ATCC 10876), Staphylococcus aureus (NCTC 6571), Pseudomonas aeruginosa (ATCC 27853), and Klebsiella oxytoca (ATCC 13182), with significant inhibition concentration ranging from 0.312 mg/ml to 0.625 mg/ml. Finally, based on the data analysis of the crude extracts of the endophytes, we identified bioactive secondary metabolites with reported biological activities such as antimicrobial, anti-inflammatory, and antioxidant properties with biotechnological applications in medicine, agriculture, and other industries. This study reported for the first time bacterial endophytes associated with D. anomala, with antimicrobial activity against bacterial pathogens.

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Khan, Raja Asad Ali, Saba Najeeb, Zhenchuan Mao, Jian Ling, Yuhong Yang, Yan Li e Bingyan Xie. "Bioactive Secondary Metabolites from Trichoderma spp. against Phytopathogenic Bacteria and Root-Knot Nematode". Microorganisms 8, n. 3 (13 marzo 2020): 401. http://dx.doi.org/10.3390/microorganisms8030401.

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Losses in crops caused by plant pathogenic bacteria and parasitic nematode are increasing because of a decrease in efficacy of traditional management measures. There is an urgent need to develop nonchemical and ecofriendly based management to control plant diseases. A potential approach of controlling plant disease in the crops is the use of biocontrol agents and their secondary metabolites (SMs). Luckily fungi and especially the genus Trichoderma comprise a great number of fungal strains that are the potential producer of bioactive secondary metabolites. In this study secondary metabolites from ten Trichoderma spp. were evaluated for their antibacterial and nematicidal potential against phytopathogenic bacteria Ralstonia solanacearum, Xanthomonas compestris and plant parasitic nematode Meloidogyne incognita. Five different growth media were evaluated for the production of SMs. It was shown that SMs of different Trichoderma spp. obtained on different growth media were different in the degree of their bioactivity. Comparison of five growth media showed that SMs produced on solid wheat and STP media gave higher antibacterial activity. SMs of T. pseudoharzianum (T113) obtained on solid wheat media were more effective against the studied bacteria followed by SMs from T. asperelloides (T136), T. pseudoharzianum (T129) and T. pseudoharzianum (T160). Scanning electron microscopy (SEM) was further conducted to observe the effect of SMs on bacterial cell morphology. As evident from the SEM, SMs produced severe morphological changes, such as rupturing of the bacterial cell walls, disintegration of cell membrane and cell content leaking out. SMs from T. viridae obtained on liquid STP and solid wheat media showed the highest percent of M. incognita juveniles (J2s) mortality and inhibition in egg hatching of M. incognita. The results of our study suggest that T. pseudoharzianum (T113) and T. viridae could be selected as an effective candidate for SMs source against phytopathogenic bacteria and M. incognita respectively.

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Blin, Kai, Simon Shaw, Katharina Steinke, Rasmus Villebro, Nadine Ziemert, Sang Yup Lee, Marnix H. Medema e Tilmann Weber. "antiSMASH 5.0: updates to the secondary metabolite genome mining pipeline". Nucleic Acids Research 47, W1 (29 aprile 2019): W81—W87. http://dx.doi.org/10.1093/nar/gkz310.

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Abstract Secondary metabolites produced by bacteria and fungi are an important source of antimicrobials and other bioactive compounds. In recent years, genome mining has seen broad applications in identifying and characterizing new compounds as well as in metabolic engineering. Since 2011, the ‘antibiotics and secondary metabolite analysis shell—antiSMASH’ (https://antismash.secondarymetabolites.org) has assisted researchers in this, both as a web server and a standalone tool. It has established itself as the most widely used tool for identifying and analysing biosynthetic gene clusters (BGCs) in bacterial and fungal genome sequences. Here, we present an entirely redesigned and extended version 5 of antiSMASH. antiSMASH 5 adds detection rules for clusters encoding the biosynthesis of acyl-amino acids, β-lactones, fungal RiPPs, RaS-RiPPs, polybrominated diphenyl ethers, C-nucleosides, PPY-like ketones and lipolanthines. For type II polyketide synthase-encoding gene clusters, antiSMASH 5 now offers more detailed predictions. The HTML output visualization has been redesigned to improve the navigation and visual representation of annotations. We have again improved the runtime of analysis steps, making it possible to deliver comprehensive annotations for bacterial genomes within a few minutes. A new output file in the standard JavaScript object notation (JSON) format is aimed at downstream tools that process antiSMASH results programmatically.

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Murate, Letícia Sayuri, Admilton Gonçalves de Oliveira, Allan Yukio Higashi, André Riedi Barazetti, Ane Stefano Simionato, Caroline Santos da Silva, Glenda Cavalari Simões et al. "Activity of Secondary Bacterial Metabolites in the Control of Citrus Canker". Agricultural Sciences 06, n. 03 (2015): 295–303. http://dx.doi.org/10.4236/as.2015.63030.

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Selvin, Joseph, A. J. Huxley e A. P. Lipton. "Immunomodulatory potential of marine secondary metabolites against bacterial diseases of shrimp". Aquaculture 230, n. 1-4 (febbraio 2004): 241–48. http://dx.doi.org/10.1016/s0044-8486(03)00427-7.

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29

Sullivan, Nora L., Dimitrios S. Tzeranis, Yun Wang, Peter T. C. So e Dianne Newman. "Quantifying the Dynamics of Bacterial Secondary Metabolites by Spectral Multiphoton Microscopy". ACS Chemical Biology 6, n. 9 (15 luglio 2011): 893–99. http://dx.doi.org/10.1021/cb200094w.

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de Carvalho, Maira Peres, Patrick Türck e Wolf-Rainer Abraham. "Secondary Metabolites Control the Associated Bacterial Communities of Saprophytic Basidiomycotina Fungi". Microbes and Environments 30, n. 2 (2015): 196–98. http://dx.doi.org/10.1264/jsme2.me14139.

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31

Engel, Philipp, Maria I. Vizcaino e Jason M. Crawford. "Gut Symbionts from Distinct Hosts Exhibit Genotoxic Activity via Divergent Colibactin Biosynthesis Pathways". Applied and Environmental Microbiology 81, n. 4 (19 dicembre 2014): 1502–12. http://dx.doi.org/10.1128/aem.03283-14.

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ABSTRACTSecondary metabolites produced by nonribosomal peptide synthetase (NRPS) or polyketide synthase (PKS) pathways are chemical mediators of microbial interactions in diverse environments. However, little is known about their distribution, evolution, and functional roles in bacterial symbionts associated with animals. A prominent example is colibactin, a largely unknown family of secondary metabolites produced byEscherichia colivia a hybrid NRPS-PKS biosynthetic pathway that inflicts DNA damage upon eukaryotic cells and contributes to colorectal cancer and tumor formation in the mammalian gut. Thus far, homologs of this pathway have only been found in closely relatedEnterobacteriaceae, while a divergent variant of this gene cluster was recently discovered in a marine alphaproteobacterialPseudovibriostrain. Herein, we sequenced the genome ofFrischella perraraPEB0191, a bacterial gut symbiont of honey bees and identified a homologous colibactin biosynthetic pathway related to those found inEnterobacteriaceae. We show that the colibactin genomic island (GI) has conserved gene synteny and biosynthetic module architecture acrossF. perrara,Enterobacteriaceae, and thePseudovibriostrain. Comparative metabolomics analyses ofF. perraraandE. colifurther reveal that these two bacteria produce related colibactin pathway-dependent metabolites. Finally, we demonstrate thatF. perrara, likeE. coli, causes DNA damage in eukaryotic cellsin vitroin a colibactin pathway-dependent manner. Together, these results support that divergent variants of the colibactin biosynthetic pathway are widely distributed among bacterial symbionts, producing related secondary metabolites and likely endowing its producer with functional capabilities important for diverse symbiotic associations.

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Uche-Okereafor, Nkemdinma, Tendani Sebola, Kudzanai Tapfuma, Lukhanyo Mekuto, Ezekiel Green e Vuyo Mavumengwana. "Antibacterial Activities of Crude Secondary Metabolite Extracts from Pantoea Species Obtained from the Stem of Solanum mauritianum and Their Effects on Two Cancer Cell Lines". International Journal of Environmental Research and Public Health 16, n. 4 (19 febbraio 2019): 602. http://dx.doi.org/10.3390/ijerph16040602.

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Endophytes are microorganisms that are perceived as non-pathogenic symbionts found inside plants since they cause no symptoms of disease on the host plant. Soil conditions and geography among other factors contribute to the type(s) of endophytes isolated from plants. Our research interest is the antibacterial activity of secondary metabolite crude extracts from the medicinal plant Solanum mauritianum and its bacterial endophytes. Fresh, healthy stems of S. mauritianum were collected, washed, surface sterilized, macerated in PBS, inoculated in the nutrient agar plates, and incubated for 5 days at 30 °C. Amplification and sequencing of the 16S rRNA gene was applied to identify the isolated bacterial endophytes. These endophytes were then grown in nutrient broth for 7–14 days, after which sterilized Amberlite® XAD7HP 20–60 mesh (Merck KGaA, Darmstadt, Germany) resin was added to each culture to adsorb the secondary metabolites, which were later extracted using ethyl acetate. Concentrated crude extracts from each bacterial endophyte were tested for antibacterial activity against 11 pathogenic bacteria and two human cancer cell lines. In this study, a total of three bacterial endophytes of the Pantoea genus were identified from the stem of S. mauritianum. The antibacterial test showed that crude secondary metabolites of the endophytes and stem of S. mauritianum possessed antibacterial properties against pathogenic microbes such as Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa, with concentrations showing inhibition ranging from 0.0625 to 8.0000 mg/mL. The anticancer analysis showed an increase in cell proliferation when A549 lung carcinoma and UMG87 glioblastoma cell lines were treated with both the plant and endophytes’ crude extracts. As far as we know, this is the first study of its kind on Solanum mauritianum in South Africa showing S. mauritianum endophytes having activity against some of the common human pathogenic organisms.

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Micheluz, A., M. Sulyok, S. Manente, R. Krska, G. C. Varese e G. Ravagnan. "Fungal secondary metabolite analysis applied to Cultural Heritage: the case of a contaminated library in Venice". World Mycotoxin Journal 9, n. 3 (1 giugno 2016): 397–407. http://dx.doi.org/10.3920/wmj2015.1958.

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The secondary metabolite production of several fungal strains of Aspergillus creber, Aspergillus jensenii, Aspergillus penicillioides, Aspergillus protuberus, Aspergillus vitricola, Cladosporium cladosporioides, Eurotium chevalieri, Eurotium halophilicum, Penicillium brevicompactum and Penicillium chrysogenum were characterised by liquid chromatography tamdem mass spectometry. All fungi were isolated from both air and book covers as well as from settled dust from a contaminated library in Venice (Italy). For A. creber and A. jensenii, we identified sterigmatocystin, methoxysterigmatocystin, versicolorin A and related precursors/side metabolites from the biosynthetic pathways. Deoxybrevianamid E, neoechinulin A, pseurotin A and D, and rugulusovin were principally detected from the strains of E. halophilicum, an emerging fungal species implicated in book contaminations in specific indoor niches. The analysis of settled dust showed a wide range of toxic or bioactive fungal metabolites. Forty-five different metabolites were identified in different concentrations; in particular, high amounts of asperglaucide, alamethicin, andrastin A, terrecyclic acid and neoechinulin A were detected. Also one bacterial metabolite, chloramphenicole was detected. This study increases the knowledge about metabolite production of several fungal species, as well as on the indoor presence of fungi that are not detected by aerobiological sampling. These results emphasise how routine dusting operations are necessary and essential in order to prevent further microbiological developments in library environments.

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Senges, Christoph H. R., Arwa Al-Dilaimi, Douglas H. Marchbank, Daniel Wibberg, Anika Winkler, Brad Haltli, Minou Nowrousian, Jörn Kalinowski, Russell G. Kerr e Julia E. Bandow. "The secreted metabolome of Streptomyces chartreusis and implications for bacterial chemistry". Proceedings of the National Academy of Sciences 115, n. 10 (20 febbraio 2018): 2490–95. http://dx.doi.org/10.1073/pnas.1715713115.

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Actinomycetes are known for producing diverse secondary metabolites. Combining genomics with untargeted data-dependent tandem MS and molecular networking, we characterized the secreted metabolome of the tunicamycin producer Streptomyces chartreusis NRRL 3882. The genome harbors 128 predicted biosynthetic gene clusters. We detected >1,000 distinct secreted metabolites in culture supernatants, only 22 of which were identified based on standards and public spectral libraries. S. chartreusis adapts the secreted metabolome to cultivation conditions. A number of metabolites are produced iron dependently, among them 17 desferrioxamine siderophores aiding in iron acquisition. Eight previously unknown members of this long-known compound class are described. A single desferrioxamine synthesis gene cluster was detected in the genome, yet different sets of desferrioxamines are produced in different media. Additionally, a polyether ionophore, differentially produced by the calcimycin biosynthesis cluster, was discovered. This illustrates that metabolite output of a single biosynthetic machine can be exquisitely regulated not only with regard to product quantity but also with regard to product range. Compared with chemically defined medium, in complex medium, total metabolite abundance was higher, structural diversity greater, and the average molecular weight almost doubled. Tunicamycins, for example, were only produced in complex medium. Extrapolating from this study, we anticipate that the larger part of bacterial chemistry, including chemical structures, ecological functions, and pharmacological potential, is yet to be uncovered.

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Wang, Ya-Nan, Ling-Hong Meng e Bin-Gui Wang. "Progress in Research on Bioactive Secondary Metabolites from Deep-Sea Derived Microorganisms". Marine Drugs 18, n. 12 (2 dicembre 2020): 614. http://dx.doi.org/10.3390/md18120614.

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Deep sea has an extreme environment which leads to biodiversity of microorganisms and their unique physical and biochemical mechanisms. Deep-sea derived microorganisms are more likely to produce novel bioactive substances with special mechanism of action for drug discovery. This article reviews secondary metabolites with biological activities such as anti-tumor, anti-bacterial, anti-viral, and anti-inflammatory isolated from deep-sea fungi and bacteria during 2018–2020. Effective methods for screening and obtaining natural active compounds from deep-sea microorganisms are also summarized, including optimizing the culture conditions, using genome mining technology, biosynthesis and so on. The comprehensive application of these methods makes broader prospects for the development and application of deep sea microbial bioactive substances.

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Matz, Carsten, Peter Deines, Jens Boenigk, Hartmut Arndt, Leo Eberl, Staffan Kjelleberg e Klaus JÃ¯Â¿Â½rgens. "Impact of Violacein-Producing Bacteria on Survival and Feeding of Bacterivorous Nanoflagellates". Applied and Environmental Microbiology 70, n. 3 (marzo 2004): 1593–99. http://dx.doi.org/10.1128/aem.70.3.1593-1599.2004.

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ABSTRACT We studied the role of bacterial secondary metabolites in the context of grazing protection against protozoans. A model system was used to examine the impact of violacein-producing bacteria on feeding rates, growth, and survival of three common bacterivorous nanoflagellates. Freshwater isolates of Janthinobacterium lividum and Chromobacterium violaceum produced the purple pigment violacein and exhibited acute toxicity to the nanoflagellates tested. High-resolution video microscopy revealed that these bacteria were ingested by the flagellates at high rates. The uptake of less than three bacteria resulted in rapid flagellate cell death after about 20 min and cell lysis within 1 to 2 h. In selectivity experiments with nontoxic Pseudomonas putida MM1, flagellates did not discriminate against pigmented strains. Purified violacein from cell extracts of C. violaceum showed high toxicity to nanoflagellates. In addition, antiprotozoal activity was found to positively correlate with the violacein content of the bacterial strains. Pigment synthesis in C. violaceum is regulated by an N-acylhomoserine lactone (AHL)-dependent quorum-sensing system. An AHL-deficient, nonpigmented mutant provided high flagellate growth rates, while the addition of the natural C. violaceum AHL could restore toxicity. Moreover, it was shown that the presence of violacein-producing bacteria in an otherwise nontoxic bacterial diet considerably inhibited flagellate population growth. Our results suggest that violacein-producing bacteria possess a highly effective survival mechanism which may exemplify the potential of some bacterial secondary metabolites to undermine protozoan grazing pressure and population dynamics.

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Kim, Young Cheol, Johan Leveau, Brian B. McSpadden Gardener, Elizabeth A. Pierson, Leland S. Pierson e Choong-Min Ryu. "The Multifactorial Basis for Plant Health Promotion by Plant-Associated Bacteria". Applied and Environmental Microbiology 77, n. 5 (7 gennaio 2011): 1548–55. http://dx.doi.org/10.1128/aem.01867-10.

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ABSTRACTOn plants, microbial populations interact with each other and their host through the actions of secreted metabolites. However, the combined action of diverse organisms and their different metabolites on plant health has yet to be fully appreciated. Here, the multifactorial nature of these interactions, at the organismal and molecular level, leading to the biological control of plant diseases is reviewed. To do so, we describe in detail the ecological significance of three different classes of secondary metabolites and discuss how they might contribute to biological control. Specifically, the roles of auxin, acetoin, and phenazines are considered, because they represent very different but important types of secondary metabolites. We also describe how studies of the global regulation of bacterial secondary metabolism have led to the discovery of new genes and phenotypes related to plant health promotion. In conclusion, we describe three avenues for future research that will help to integrate these complex and diverse observations into a more coherent synthesis of bacterially mediated biocontrol of plant diseases.

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Morgan, Stephanie, Matthew J. Thomas, Katherine M. Walstrom, Eric C. Warrick e Brittany J. Gasper. "Characterization of prodiginine compounds produced by a Vibrio species isolated from salt flat sediment along the Florida Gulf Coast". Fine Focus 3, n. 1 (1 marzo 2017): 33–51. http://dx.doi.org/10.33043/ff.3.1.33-51.

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Abstract (sommario):

Prodiginines are secondary metabolites produced by several known species of bacteria. These metabolites are known for their bright pigmentation and their potential medicinal uses. Biosynthesis of prodiginine compounds, including the well-studied prodigiosin, has been well characterized in Serratia marcescens and other bacterial species, including several marine bacteria. In an effort to isolate and identify natural products from marine organisms, an environmental sample was taken from a salt flat along the Florida Gulf Coast and cultured for bacterial growth. A bacterial species that produces a vibrant pink pigment was isolated and identified as a member of the Vibrio genus and was named MI-2. Whole genome sequencing identified a 13-gene operon with homology to the S. marcescens prodigiosin biosynthetic operon. The pigment produced by MI-2 was hypothesized to be composed of prodigiosin or related prodiginine compounds and was purified by flash column chromatography and identified by mass spectrometry.

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Sebola, Tendani E., Nkemdinma C. Uche-Okereafor, Lukhanyo Mekuto, Maya Mellisa Makatini, Ezekiel Green e Vuyo Mavumengwana. "Antibacterial and Anticancer Activity and Untargeted Secondary Metabolite Profiling of Crude Bacterial Endophyte Extracts from Crinum macowanii Baker Leaves". International Journal of Microbiology 2020 (10 dicembre 2020): 1–15. http://dx.doi.org/10.1155/2020/8839490.

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This study isolated and identified endophytic bacteria from the leaves of Crinum macowanii and investigated the potential of the bacterial endophyte extracts as antibacterial and anticancer agents and their subsequent secondary metabolites. Ethyl acetate extracts from the endophytes and the leaves (methanol: dichloromethane (1 : 1)) were used for antibacterial activity against selected pathogenic bacterial strains by using the broth microdilution method. The anticancer activity against the U87MG glioblastoma and A549 lung carcinoma cells was determined by the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy-phenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay. Bacterial endophytes that were successfully isolated from C. macowanii leaves include Raoultella ornithinolytica, Acinetobacter guillouiae, Pseudomonas sp., Pseudomonas palleroniana, Pseudomonas putida, Bacillus safensis, Enterobacter asburiae, Pseudomonas cichorii, and Arthrobacter pascens. Pseudomonas cichorii exhibited broad antibacterial activity against both Gram-negative and Gram-positive pathogenic bacteria while Arthrobacter pascens displayed the least MIC of 0.0625 mg/mL. Bacillus safensis crude extracts were the only sample that showed notable cell reduction of 50% against A549 lung carcinoma cells at a concentration of 100 μg/mL. Metabolite profiling of Bacillus safensis, Pseudomonas cichorii, and Arthrobacter pascens crude extracts revealed the presence of known antibacterial and/or anticancer agents such as lycorine (1), angustine (2), crinamidine (3), vasicinol (4), and powelline. It can be concluded that the crude bacterial endophyte extracts obtained from C. macowanii leaves can biosynthesize bioactive compounds and can be bioprospected for medical application into antibacterial and anticancer agents.

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Ciric, Ana, Anastasia Karioti, Jasmina Glamoclija, Marina Sokovic e Helen Skaltsa. "Antimicrobial activity of secondary metabolites isolated from Centaurea spruneri Boiss.& Heldr." Journal of the Serbian Chemical Society 76, n. 1 (2011): 27–34. http://dx.doi.org/10.2298/jsc100127008c.

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Abstract (sommario):

Two coumarins, scopoletin (1) and isoscopoletin (2), two simple phenolic acids, protocatechuic acid (3) and isovanillic acid (4) and one flavonoid, eriodictyol (5) were isolated from the aerial parts of Centaurea spruneri. The structure of the compounds was established by spectroscopic methods. The in vitro antimicrobial activity of the isolated compounds was tested against eight bacteria and eight fungal species, using a microdilution method. All compounds tested showed moderate antibacterial and antifungal activities. Their minimum inhibitory concentrations were in the range 0.655 - 2.38 ?mol ml-1 and their minimal bactericidal concentrations ranged from 0.694 to 4.15 ?mol ml-1 against the tested bacterial species. All compounds showed fungistatic activity at 0.259 - 2.38 ?mol ml-1 and fungicidal at 0.69 - 2.6 ?mol ml-1 against all fungi tested.

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Setiaji, Jarod, Feli Feliatra, Hilwan Yuda Teruna, Iesje Lukistyowati, Indra Suharman, Zainal Abidin Muchlisin e Teuku Iskandar Johan. "Antibacterial activity in secondary metabolite extracts of heterotrophic bacteria against Vibrio alginolyticus, Aeromonas hydrophila, and Pseudomonas aeruginosa". F1000Research 9 (21 dicembre 2020): 1491. http://dx.doi.org/10.12688/f1000research.26215.1.

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Abstract (sommario):

Background: Disease causing bacteria such as Vibrio alginolyticus, Aeromonas hydrophila, and Pseudomonas aeruginosa present a problem for fish farming. Treatment to remove them are generally carried out using antibiotics which have side effects on fish, the environment and humans. However, the use of antibacterial compounds derived from heterotrophic bacteria serve as a good alternative for antibiotics. Therefore, this study aimed to explore antibacterial activity in the secondary metabolite extracts of heterotrophic bacteria against Vibrio alginolyticus, Aeromonas hydrophila, and Pseudomonas aeruginosa. Methods: Heterotrophic bacteria namely Bacillus sp. JS04 MT102913.1, Bacillus toyonensis JS08 MT102920.1, Bacillus cereus JS10 MT102922.1, Bacillus sp. JS11 MT102923.1, Pseudoalteromonas sp. JS19 MT102924.1, Bacillus cereus JS22 MT102926.1, and Bacillus sp. strain JS25 MT102927.1 were used in this study. The sequences of these bacteria have been deposited and are available from NCBI GenBank. Each heterotrophic bacterium was cultured on 6L nutrient broth for 8 days, and extracts produced using ethyl acetate to obtain their secondary metabolites. These extracts were tested for their phytochemical contents using FT-IR and also tested for their inhibitory property in pathogenic bacteria by agar diffusion method. Results: Phytochemical test results showed that the seven heterotrophic bacterial isolates produced terpenoid compounds. Based on the inhibitory test, the secondary metabolite extracts from Bacillus sp strain JS04 had the highest inhibitory effect on the growth of pathogenic bacteria namely, V. alginolyticus (17.5 mm), A. hydrophila (16.8 mm), and P. aeruginosa (17.3 mm). Conclusion: It was concluded that the secondary metabolite extracts of heterotrophic bacteria inhibit the growth of V. alginolyticus, A. hydrophila, and P. aeruginosa.

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Núñez-Montero, Kattia, Damián Quezada-Solís, Zeinab G. Khalil, Robert J. Capon, Fernando D. Andreote e Leticia Barrientos. "Genomic and Metabolomic Analysis of Antarctic Bacteria Revealed Culture and Elicitation Conditions for the Production of Antimicrobial Compounds". Biomolecules 10, n. 5 (27 aprile 2020): 673. http://dx.doi.org/10.3390/biom10050673.

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Abstract (sommario):

Concern about finding new antibiotics against drug-resistant pathogens is increasing every year. Antarctic bacteria have been proposed as an unexplored source of bioactive metabolites; however, most biosynthetic gene clusters (BGCs) producing secondary metabolites remain silent under common culture conditions. Our work aimed to characterize elicitation conditions for the production of antibacterial secondary metabolites from 34 Antarctic bacterial strains based on MS/MS metabolomics and genome mining approaches. Bacterial strains were cultivated under different nutrient and elicitation conditions, including the addition of lipopolysaccharide (LPS), sodium nitroprusside (SNP), and coculture. Metabolomes were obtained by HPLC-QTOF-MS/MS and analyzed through molecular networking. Antibacterial activity was determined, and seven strains were selected for genome sequencing and analysis. Biosynthesis pathways were activated by all the elicitation treatments, which varies among strains and dependents of culture media. Increased antibacterial activity was observed for a few strains and addition of LPS was related with inhibition of Gram-negative pathogens. Antibiotic BGCs were found for all selected strains and the expressions of putative actinomycin, carotenoids, and bacillibactin were characterized by comparison of genomic and metabolomic data. This work established the use of promising new elicitors for bioprospection of Antarctic bacteria and highlights the importance of new “-omics” comparative approaches for drug discovery.

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Tshikhudo, Phumudzo, Khayalethu Ntushelo, Fhatuwani Mudau, Bahare Salehi, Mehdi Sharifi-Rad, Natália Martins, Miquel Martorell e Javad Sharifi-Rad. "Understanding Camellia sinensis using Omics Technologies along with Endophytic Bacteria and Environmental Roles on Metabolism: A Review". Applied Sciences 9, n. 2 (14 gennaio 2019): 281. http://dx.doi.org/10.3390/app9020281.

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Abstract (sommario):

Camellia sinensis is the most consumed beverage worldwide. It contains a wide variety of secondary metabolites, such as alkaloids, saponins, tannins, catechins, and polyphenols, generated through a condensation reaction of cinnamic acid with three malonyl-CoA groups. In addition to the metabolic processes occurring within this plant, there are also some plant-associated bacterial endophytes. These bacteria reside in the living tissues of the host plants without causing any harmful effect to them, thereby stimulating secondary metabolite production with a diverse range of biological effects. Omics technologies reveal understanding of the biological phenomena of transcriptomics, proteomics, and metabolomics. In this sense, the present review aims to provide a comprehensive review of various methods used to identify distinct plant compounds, namely transcriptomic, proteomic, and metabolomic analysis. The role of endophytic bacteria in C. sinensis metabolism, and C. sinensis antioxidant and antimicrobial effects, are also carefully highlighted.

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Zarins-Tutt, Joseph Scott, Tania Triscari Barberi, Hong Gao, Andrew Mearns-Spragg, Lixin Zhang, David J. Newman e Rebecca Jane Miriam Goss. "Prospecting for new bacterial metabolites: a glossary of approaches for inducing, activating and upregulating the biosynthesis of bacterial cryptic or silent natural products". Natural Product Reports 33, n. 1 (2016): 54–72. http://dx.doi.org/10.1039/c5np00111k.

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45

Brescia, Francesca, Anthi Vlassi, Ana Bejarano, Bernard Seidl, Martina Marchetti-Deschmann, Rainer Schuhmacher e Gerardo Puopolo. "Characterisation of the Antibiotic Profile of Lysobacter capsici AZ78, an Effective Biological Control Agent of Plant Pathogenic Microorganisms". Microorganisms 9, n. 6 (17 giugno 2021): 1320. http://dx.doi.org/10.3390/microorganisms9061320.

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Determining the mode of action of microbial biocontrol agents plays a key role in their development and registration as commercial biopesticides. The biocontrol rhizobacterium Lysobacter capsici AZ78 (AZ78) is able to inhibit a vast array of plant pathogenic oomycetes and Gram-positive bacteria due to the release of antimicrobial secondary metabolites. A combination of MALDI-qTOF-MSI and UHPLC-HRMS/M was applied to finely dissect the AZ78 metabolome and identify the main secondary metabolites involved in the inhibition of plant pathogenic microorganisms. Under nutritionally limited conditions, MALDI-qTOF-MSI revealed that AZ78 is able to release a relevant number of antimicrobial secondary metabolites belonging to the families of 2,5-diketopiperazines, cyclic lipodepsipeptides, macrolactones and macrolides. In vitro tests confirmed the presence of secondary metabolites toxic against Pythium ultimum and Rhodococcus fascians in AZ78 cell-free extracts. Subsequently, UHPLC-HRMS/MS was used to confirm the results achieved with MALDI-qTOF-MSI and investigate for further putative antimicrobial secondary metabolites known to be produced by Lysobacter spp. This technique confirmed the presence of several 2,5-diketopiperazines in AZ78 cell-free extracts and provided the first evidence of the production of the cyclic depsipeptide WAP-8294A2 in a member of L. capsici species. Moreover, UHPLC-HRMS/MS confirmed the presence of dihydromaltophilin/Heat Stable Antifungal Factor (HSAF) in AZ78 cell-free extracts. Due to the production of HSAF by AZ78, cell-free supernatants were effective in controlling Plasmopara viticola on grapevine leaf disks after exposure to high temperatures. Overall, our work determined the main secondary metabolites involved in the biocontrol activity of AZ78 against plant pathogenic oomycetes and Gram-positive bacteria. These results might be useful for the future development of this bacterial strain as the active ingredient of a microbial biopesticide that might contribute to a reduction in the chemical input in agriculture.

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Pyle, S., R. A. Rastall e G. R. Gibson. "Metabolism of Wheat Dextrin, Partially Hydrolysed Guar Gum and Inulin by Bifidobacterium lactis or Lactobacillus acidophilus in an In Vitro Gut Model Fermentation System". International Journal of Probiotics and Prebiotics 16, n. 1 (4 gennaio 2021): 22–30. http://dx.doi.org/10.37290/ijpp2641-7197.16:22-30.

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Combining the fibres wheat dextrin (WD), partially hydrolysed guar gum (PHGG) and inulin with probiotics Lactobacillus acidophilus NCFM (NCFM) or Bifidobacterium lactis HN019 (HN019) may enhance bacterial metabolites leading to a healthier gut community. The aim of this study was to determine whether WD, PHGG and inulin or NCFM and HN019 alone generate a more favourable gut bacterial community than when combined. A secondary aim was to assess organic acid production following prebiotics, probiotics and synbiotic fermentation. An in vitro gut model batch culture fermentation was run for 72h. Samples were collected for bacterial enumeration (fluorescent in situ hybridisation combined with flow cytometry) and organic acid production (gas chromatography). Inulin and HN019 combination significantly increased bifidobacteria compared to inulin alone. Additionally, a significant increase in lactic acid bacteria, Bacteroides and Clostridium coccoides-Eubacterium rectale was found in the inulin containing probiotic vessels. The WD and PHGG vessels combined with the probiotic did not show any alteration in bacterial metabolism compared to the dietary fibres alone. In conclusion, synbiotic inulin combined with either HN019 or NCFM may help to enhance bacterial metabolites and cross-feeding to lead to a prolonged elevation in Bifidobacterium spp., and lactic acid bacteria.

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Jousset, Alexandre, Enrique Lara, Luis G. Wall e Claudio Valverde. "Secondary Metabolites Help Biocontrol Strain Pseudomonas fluorescens CHA0 To Escape Protozoan Grazing". Applied and Environmental Microbiology 72, n. 11 (novembre 2006): 7083–90. http://dx.doi.org/10.1128/aem.00557-06.

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ABSTRACT In soil ecosystems, bacteria must cope with predation activity, which is attributed mainly to protists. The development of antipredation strategies may help bacteria maintain higher populations and persist longer in the soil. We analyzed the interaction between the root-colonizing and biocontrol strain Pseudomonas fluorescens CHA0 and three different protist isolates (an amoeba, a flagellate, and a ciliate). CHA0 produces a set of antibiotics, HCN, and an exoprotease. We observed that protists cannot grow on CHA0 but can multiply on isogenic regulatory mutants that do not produce the extracellular metabolites. The in vitro responses to CHA0 cells and its exoproducts included growth inhibition, encystation, paralysis, and cell lysis. By analyzing the responses of protists to bacterial supernatants obtained from different isogenic mutants whose production of one or more exometabolites was affected and also to culture extracts with antibiotic enrichment, we observed different contributions of the phenolic antifungal compound 2,4-diacetylphloroglucinol (DAPG) and the extracellular protease AprA to CHA0 toxicity for protists and to the encystation-reactivation cycle. The grazing pressure artificially produced by a mixture of the three protists in a microcosm system resulted in reduced colonization of cucumber roots by a regulatory isogenic CHA0 mutant unable to produce toxins. These results suggest that exometabolite production in biocontrol strain CHA0 may contribute to avoidance of protist grazing and help sustain higher populations in the rhizosphere, which may be a desirable and advantageous trait for competition with other bacteria for available resources.

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Handayani, Rezqi, Nurul Qamariah e Saftaria Ayu Mardova. "Uji Daya Hambat Ekstrak Etanol Batang Saluang Belum terhadap Bakteri Escherichia coli". Borneo Journal of Pharmacy 1, n. 1 (1 maggio 2018): 16–18. http://dx.doi.org/10.33084/bjop.v1i1.237.

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Saluang Belum one of the herbal plants that have the benefits as a traditional medicine in Central Kalimantan. People in Central Kalimantan trusted Saluang Belum stem have an empirical benefit as a stamina enhancing agent and as an antioxidant. From previous research, Saluang Belum stem has a secondary metabolite that was saponin and tannin. Of these two secondary metabolites scientifically have pharmacological effects one of which was able to inhibit bacterial growth. To prove it in this research, the inhibitory test of ethanol extract of Saluang Belum stem from the growth of Escherichia coli bacteria. The inhibitory test method used in this study was the diffusion method using a variety of concentrations of 0.5%, 1%, 5%, 10%, and 15%. The result of this research, that there was not inhibition zone on the media used in all concentration. From these results can be concluded Saluang Belum stem ethanol extract unable to inhibit the growth of E. coli bacteria at concentrations of 0.5%, 1%, 5%, 10%, and 15%.

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Raimundo, Inês, Sandra Silva, Rodrigo Costa e Tina Keller-Costa. "Bioactive Secondary Metabolites from Octocoral-Associated Microbes—New Chances for Blue Growth". Marine Drugs 16, n. 12 (4 dicembre 2018): 485. http://dx.doi.org/10.3390/md16120485.

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Octocorals (Cnidaria, Anthozoa Octocorallia) are magnificent repositories of natural products with fascinating and unusual chemical structures and bioactivities of interest to medicine and biotechnology. However, mechanistic understanding of the contribution of microbial symbionts to the chemical diversity of octocorals is yet to be achieved. This review inventories the natural products so-far described for octocoral-derived bacteria and fungi, uncovering a true chemical arsenal of terpenes, steroids, alkaloids, and polyketides with antibacterial, antifungal, antiviral, antifouling, anticancer, anti-inflammatory, and antimalarial activities of enormous potential for blue growth. Genome mining of 15 bacterial associates (spanning 12 genera) cultivated from Eunicella spp. resulted in the identification of 440 putative and classifiable secondary metabolite biosynthetic gene clusters (BGCs), encompassing varied terpene-, polyketide-, bacteriocin-, and nonribosomal peptide-synthase BGCs. This points towards a widespread yet uncharted capacity of octocoral-associated bacteria to synthetize a broad range of natural products. However, to extend our knowledge and foster the near-future laboratory production of bioactive compounds from (cultivatable and currently uncultivatable) octocoral symbionts, optimal blending between targeted metagenomics, DNA recombinant technologies, improved symbiont cultivation, functional genomics, and analytical chemistry are required. Such a multidisciplinary undertaking is key to achieving a sustainable response to the urgent industrial demand for novel drugs and enzyme varieties.

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Soesanto, Loekas, Clarissa Nadya Pradiptha e Endang Mugiastuti. "Raw Secondary Metabolites of Chitosan-enriched Pseudomonas fluorescens P60 to Control Corn Sheath Blight". Biosaintifika: Journal of Biology & Biology Education 13, n. 1 (15 aprile 2021): 113–20. http://dx.doi.org/10.15294/biosaintifika.v13i1.28775.

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Corn is a strategic cereal with economic value and always face the corn sheath blight in the field. An alternative safely and environmentally friendly disease control is the use of biological agent Pseudomonas fluorescens P60 that produced raw secondary metabolites. This study aimed to test the effectiveness of chitosan enriched P. fluorescens P60 raw secondary metabolites against leaf blight and to determine the effect on the growth of maize. The research was conducted at the Laboratory of Plant Protection and Experimental Farm, Faculty of Agriculture, Jenderal Soedirman University. In vitro test used a completely randomized design and in planta test used a randomized block design consisted of four treatments and six replicates. The treatments consisted of control and the secondary metabolites of P. fluorescens P60 enriched with chitosan 1, 2, and 3%. Variables observed were inhibition ability, chitinase and protease analysis qualitatively, incubation period, disease intensity, infection rate, AUDPC, crop height, crop fresh weight, and root fresh weight. The results showed that the secondary metabolites of P. fluorescens P60 enriched with chitosan 3% was effective in inhibiting the growth of Rhizoctonia solani as 63.3%, produced chitinase and protease, and could control the disease by delaying the incubation period as 79.05%, lowering the disease intensity as 68.68%, lowering the infection rate as 100%, and lowering AUDPC as 83.32%. The secondary metabolites of P. fluorescens P60 enriched with chitosan 3% was effective in improving plant growth by increasing plant fresh weight as 33.9% and root fresh weight as 43.09% compared to control. Chitosan could be used for improving effectiveness of antagonistic bacteria raw secondary metabolites. The raw secondary metabolites of bacterial antagonists could be improved their effectiveness against plant diseases by enrichment of chitosan.

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