Microcystins are cyanobacterial toxins that represent a serious threat to drinking water and recreational lakes worldwide. Here, we show microcystin fulfils an important function within cells of its natural producer Microcystis. The deficient mutant ΔmcyB showed significant changes in the accumulation proteins, including several enzymes Calvin cycle, phycobiliproteins two NADPH-dependent reductases. We have discovered binds number these proteins vivo binding is strongly enhanced under high...

Rhizonin is a hepatotoxic cyclopeptide isolated from cultures of fungal Rhizopus microsporus strain that grew on moldy ground nuts in Mozambique. Reinvestigation this by series experiments unequivocally revealed "first mycotoxin lower fungi" actually not produced the fungus. PCR and phylogenetic studies based 16S rRNA gene sequences fungus associated with bacteria belonging to genus Burkholderia. By transmission electron microscopy, were localized within cytosol. Toxin production presence...

Aeruginosins are bioactive oligopeptides that produced in high structural diversity by strains of the bloom-forming cyanobacterial genera Microcystis and Planktothrix. A hallmark aeruginosins is unusual Choi moiety central to tetrapeptides, while other positions occupied variable moieties individual congeners. Here we report on three aeruginosin synthetase gene clusters (aer) aeruginosa (strains PCC 7806, NIES-98, NIES-843). The analysis comparison aer provide first insight into molecular...

Abstract Siderophores are key players in bacteria–host interactions, with the main function to provide soluble iron for their producers. Gramibactin from rhizosphere bacteria expands siderophore and diversity as it delivers host plant features an unusual diazeniumdiolate moiety chelation. By mutational analysis of grb gene cluster, we identified genes (grbD grbE) necessary formation. Genome mining using a GrbD‐based network revealed broad range orthologous clusters mainly plant‐associated...

Kawaguchipeptin B, an antibacterial cyclic undecapeptide, was isolated from the cultured cyanobacterium Microcystis aeruginosa (NIES-88). Its structure elucidated as 1 on basis of 2D NMR data and chemical degradation. B (1) inhibited growth Gram-positive bacterium Staphylococcus aureus at a concentration μg/mL (MIC).

Protecting against too much of a good thing The slimy pink rot potatoes is caused by the bacterium Clostridium puniceum , which cannot grow in presence oxygen. These bacteria produce polyphenolic metabolite known as clostrubin that functions an antibiotic. Shabuer et al. now show also use to protect themselves from aerobic environment potato tuber. Science this issue p. 670

Abstract Bacteria of the Burkholderia pseudomallei (BP) group pose a global health threat, causing infectious diseases melioidosis, common cause pneumonia and sepsis, glanders, contagious zoonosis. A trait BP bacteria is conserved gene cluster coding for biosynthesis polyketides (malleicyprols) with reactive cyclopropanol unit that critical virulence. Enzymes building this warhead represent ideal targets antivirulence strategies but biochemical basis formation unknown. Here we describe...

Kasumigamide (1), a novel antialgal tetrapeptide containing an N-terminal α-hydroxy acid, was isolated from the freshwater cyanobacterium Microcystis aeruginosa (NIES-87). Its structure elucidated by two-dimensional 1H−1H and 1H−13C NMR correlation experiments confirmed mass spectral amino acid analyses. The absolute stereochemistry of 1 determined chemical studies. This peptide showed activity against green alga Chlamydomonas neglecta (NIES-439).

The elusive structure of malleobactin, a virulence factor pathogens belonging to the Burkholderia mallei family, was finally unveiled by genetic and chemical analyses. novel nitro-substituted siderophore is derived from an unusual, unprotected hydroxylamine, which undergoes spontaneous oxidation, as shown in vitro assays detection analogues featuring hydroxylamino, nitroso, azoxide groups. As service our authors readers, this journal provides supporting information supplied authors. Such...

Abstract In microbial interactions bacteria employ diverse molecules with specific functions, such as sensing the environment, communication other microbes or hosts, and conferring virulence. Insights into molecular basis of bacterial are thus high relevance for ecology medicine. Targeted gene activation in vitro studies revealed that cell‐to‐cell signaling molecule disease mediator IQS (aeruginaldehyde) human pathogen Pseudomonas aeruginosa related derives from siderophore pyochelin....

ABSTRACT Terrestrial symbiotic cyanobacteria of the genus Nostoc exhibit a large potential for production bioactive natural products nonribosomal peptide, polyketide, and ribosomal peptide classes, yet most biosynthetic gene clusters are silent under conventional cultivation conditions. In present study, we utilized high-density approach recently developed phototrophic bacteria to rapidly generate biomass filamentous up density 400 g (wet weight)/liter. Unexpectedly, integrated...

Microcyclamide (1), a cytotoxic cyclic hexapeptide, was isolated from the cultured cyanobacterium Microcystis aeruginosa (NIES-298). Its structure elucidated to be 1 on basis of two-dimensional 1H−1H, 1H−13C, and 1H−15N NMR correlation experiments HRFABMS measurement. The absolute stereochemistry asymmetric centers determined by Marfey's method. This peptide showed moderate cytotoxicity against P388 murine leukemia cells.

The convergent total synthesis of polycarcin V, a gilvocarcin-type natural product that shows significant cytotoxicity with selectivity for nonsmall-cell lung cancer, breast and melanoma cells, has been achieved in 13 steps from 7, 8, 22; the sequence features stereoselective α-C-glycosylation reaction union protected carbohydrate 7 naphthol 8. association constant binding V to duplex DNA is similar previously reported gilvocarcin V.

Burkholderia species such as B. mallei and pseudomallei are bacterial pathogens causing fatal infections in humans animals (glanders melioidosis), yet knowledge on their virulence factors is limited. While pathogenic effects have been linked to a highly conserved gene locus (bur/mal) the group, metabolite associated encoded polyketide synthase, burkholderic acid (syn. malleilactone), could not explain observed phenotypes. By metabolic profiling molecular network analyses of model organism...

Cellulose degradation by anaerobic bacteria plays an eminent role in the global carbon cycle and is a critical step biofuel production. The anaerobe thermophile Clostridium thermocellum (now: Acetivibrio thermocellus) particularly efficient at breaking down biomass produces 'yellow affinity substance' (YAS), pigment that has been implicated signaling conferring higher of cellulosome to YAS‐loaded cellulose. However, despite its importance, nature biosynthetic origin YAS have remained...