A Possible Role for Exocytosis in Aflatoxin Export in Aspergillus parasiticus

ABSTRACT Filamentous fungi synthesize bioactive secondary metabolites with major human health and economic impacts. Little is known about the mechanisms that mediate the export of these metabolites to the cell exterior. Aspergillus parasiticus synthesizes aflatoxin, a secondary metabolite that is one of the most potent naturally occurring carcinogens known. We previously demonstrated that aflatoxin is synthesized and compartmentalized in specialized vesicles called aflatoxisomes and that these subcellular organelles also play a role in the export process. In the current study, we tested the hypothesis that aflatoxisomes fuse with the cytoplasmic membrane to facilitate the release of aflatoxin into the growth environment. Microscopic analysis of A. parasiticus grown under aflatoxin-inducing and non-aflatoxin-inducing conditions generated several lines of experimental evidence that supported the hypothesis. On the basis of the evidence, we propose that export of the mycotoxin aflatoxin in Aspergillus parasiticus occurs by exocytosis, and we present a model to illustrate this export mechanism.

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Complete Genome Sequence of the Lignocellulose-Degrading Actinomycete Streptomyces albus CAS922

Microbiology Resource Announcements ◽

10.1128/mra.00227-20 ◽

2020 ◽

Vol 9 (21) ◽

Author(s):

Anna Tippelt ◽

Markus Nett ◽

M. Soledad Vela Gurovic

Keyword(s):

Secondary Metabolites ◽

Complete Genome Sequence ◽

Sunflower Seed ◽

Gene Clusters ◽

Biosynthetic Gene ◽

Biosynthetic Gene Clusters ◽

Carbohydrate Active Enzymes ◽

Content Type ◽

Bioactive Secondary Metabolites ◽

Streptomyces Albus

ABSTRACT Streptomyces albus CAS922 was isolated from sunflower seed hulls. Its fully sequenced genome harbors a multitude of genes for carbohydrate-active enzymes, which likely facilitate growth on lignocellulosic biomass. Furthermore, the presence of 27 predicted biosynthetic gene clusters indicates a significant potential for the production of bioactive secondary metabolites.

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Moorea producens gen. nov., sp. nov. and Moorea bouillonii comb. nov., tropical marine cyanobacteria rich in bioactive secondary metabolites

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY ◽

10.1099/ijs.0.033761-0 ◽

2012 ◽

Vol 62 (Pt_5) ◽

pp. 1171-1178 ◽

Cited By ~ 161

Author(s):

Niclas Engene ◽

Erin C. Rottacker ◽

Jan Kaštovský ◽

Tara Byrum ◽

Hyukjae Choi ◽

...

Keyword(s):

Secondary Metabolites ◽

Polyketide Synthase ◽

Botanical Nomenclature ◽

Distinctive Character ◽

Content Type ◽

Algae Blooms ◽

Rich Diversity ◽

Peptide Synthetase ◽

Bioactive Secondary Metabolites ◽

Micro Organisms

The filamentous cyanobacterial genus Moorea gen. nov., described here under the provisions of the International Code of Botanical Nomenclature, is a cosmopolitan pan-tropical group abundant in the marine benthos. Members of the genus Moorea are photosynthetic (containing phycocyanin, phycoerythrin, allophycocyanin and chlorophyll a), but non-diazotrophic (lack heterocysts and nitrogenase reductase genes). The cells (discoid and 25–80 µm wide) are arranged in long filaments (<10 cm in length) and often form extensive mats or blooms in shallow water. The cells are surrounded by thick polysaccharide sheaths covered by a rich diversity of heterotrophic micro-organisms. A distinctive character of this genus is its extraordinarily rich production of bioactive secondary metabolites. This is matched by genomes rich in polyketide synthase and non-ribosomal peptide synthetase biosynthetic genes which are dedicated to secondary metabolism. The encoded natural products are sometimes responsible for harmful algae blooms and, due to morphological resemblance to the genus Lyngbya , this group has often been incorrectly cited in the literature. We here describe two species of the genus Moorea: Moorea producens sp. nov. (type species of the genus) with 3LT as the nomenclature type, and Moorea bouillonii comb. nov. with PNG5-198R as the nomenclature type.

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Lysobacter enzymogenes Uses Two Distinct Cell-Cell Signaling Systems for Differential Regulation of Secondary-Metabolite Biosynthesis and Colony Morphology

Applied and Environmental Microbiology ◽

10.1128/aem.01841-13 ◽

2013 ◽

Vol 79 (21) ◽

pp. 6604-6616 ◽

Cited By ~ 49

Author(s):

Guoliang Qian ◽

Yulan Wang ◽

Yiru Liu ◽

Feifei Xu ◽

Ya-Wen He ◽

...

Keyword(s):

Secondary Metabolites ◽

Cell Signaling ◽

Secondary Metabolite ◽

Colony Morphology ◽

Content Type ◽

Signaling Systems ◽

Lysobacter Enzymogenes ◽

Bioactive Secondary Metabolites ◽

Secondary Metabolite Biosynthesis ◽

First Time

ABSTRACTLysobacter enzymogenesis a ubiquitous environmental bacterium that is emerging as a potentially novel biological control agent and a new source of bioactive secondary metabolites, such as the heat-stable antifungal factor (HSAF) and photoprotective polyene pigments. Thus far, the regulatory mechanism(s) for biosynthesis of these bioactive secondary metabolites remains largely unknown inL. enzymogenes. In the present study, the diffusible signal factor (DSF) and diffusible factor (DF)-mediated cell-cell signaling systems were identified for the first time fromL. enzymogenes. The results show that both Rpf/DSF and DF signaling systems played critical roles in modulating HSAF biosynthesis inL. enzymogenes. Rpf/DSF signaling and DF signaling played negative and positive effects in polyene pigment production, respectively, with DF playing a more important role in regulating this phenotype. Interestingly, only Rpf/DSF, but not the DF signaling system, regulated colony morphology ofL. enzymgenes. Both Rpf/DSF and DF signaling systems were involved in the modulation of expression of genes with diverse functions inL. enzymogenes, and their own regulons exhibited only a few loci that were regulated by both systems. These findings unveil for the first time new roles of the Rpf/DSF and DF signaling systems in secondary metabolite biosynthesis ofL. enzymogenes.

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Draft Genome Sequences of Bacillus cereus E41 and Bacillus anthracis F34 Isolated from Algerian Salt Lakes

Genome Announcements ◽

10.1128/genomea.00383-17 ◽

2017 ◽

Vol 5 (20) ◽

Cited By ~ 6

Author(s):

Mohamed Seghir Daas ◽

Albert Remus R. Rosana ◽

Jeella Z. Acedo ◽

Farida Nateche ◽

Salima Kebbouche-Gana ◽

...

Keyword(s):

Secondary Metabolites ◽

Bacillus Cereus ◽

Bacillus Anthracis ◽

Salt Lake ◽

Draft Genome ◽

Salt Lakes ◽

Genome Sequences ◽

Content Type ◽

Bioactive Secondary Metabolites ◽

Eastern Algeria

ABSTRACT Two strains of Bacillus, B. cereus E41 and B. anthracis F34, were isolated from a salt lake in Aïn M’lila-Oum El Bouaghi, eastern Algeria, and Ain Baida-Ouargla, southern Algeria, respectively. Their genomes display genes for the production of several bioactive secondary metabolites, including polyhydroxyalkanoate, iron siderophores, lipopeptides, and bacteriocins.

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Advances in actinomycete research: an ActinoBase review of 2019

Microbiology ◽

10.1099/mic.0.000944 ◽

2020 ◽

Vol 166 (8) ◽

pp. 683-694 ◽

Cited By ~ 1

Author(s):

Samuel M.M. Prudence ◽

Emily Addington ◽

Laia Castaño-Espriu ◽

David R. Mark ◽

Linamaría Pintor-Escobar ◽

...

Keyword(s):

Secondary Metabolites ◽

Research Community ◽

Filamentous Bacteria ◽

Content Type ◽

Host Interactions ◽

Specialized Metabolites ◽

Gram Positive Bacteria ◽

Link Type ◽

Bioactive Secondary Metabolites ◽

Medical Importance

The actinomycetes are Gram-positive bacteria belonging to the order Actinomycetales within the phylum Actinobacteria . They include members with significant economic and medical importance, for example filamentous actinomycetes such as Streptomyces species, which have a propensity to produce a plethora of bioactive secondary metabolites and form symbioses with higher organisms, such as plants and insects. Studying these bacteria is challenging, but also fascinating and very rewarding. As a Microbiology Society initiative, members of the actinomycete research community have been developing a Wikipedia-style resource, called ActinoBase, the purpose of which is to aid in the study of these filamentous bacteria. This review will highlight 10 publications from 2019 that have been of special interest to the ActinoBase community, covering 4 major components of actinomycete research: (i) development and regulation; (ii) specialized metabolites; (iii) ecology and host interactions; and (iv) technology and methodology.

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Draft Genome Sequence of Bacillus paralicheniformis F47, Isolated from an Algerian Salty Lake

Genome Announcements ◽

10.1128/genomea.00190-18 ◽

2018 ◽

Vol 6 (13) ◽

Author(s):

Mohamed Seghir Daas ◽

Albert Remus R. Rosana ◽

Jeella Z. Acedo ◽

Malika Douzane ◽

Farida Nateche ◽

...

Keyword(s):

Secondary Metabolites ◽

Genome Sequence ◽

Draft Genome ◽

Draft Genome Sequence ◽

Content Type ◽

Bacillus Paralicheniformis ◽

Bioactive Secondary Metabolites ◽

Circular Bacteriocin

ABSTRACT Bacillus paralicheniformis F47 was isolated from a salty lake in Ain Baida-Ouargla, southern Algeria. The genome contains genes for the production of several bioactive secondary metabolites, including the siderophore bacillibactin, the lipopeptides fengycin, surfactin, and lichenysin, the antibiotics bacitracin and kanosamine, and a putative circular bacteriocin.

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