RESUMO
Myxococcus xanthus, a myxobacterium, displays phase variation between yellow phase and tan phase. We found that deletion of the encA gene encoding encapsulin and the encF gene encoding a metalloprotease causes formation of tan colonies that never transform into yellow colonies. The encA and encF mutants were defective in the production of DK-xanthene and myxovirescin. They did not produce extracellular polysaccharides; hence, the cells did not aggregate in liquid and showed reduced swarming on agar plates. The mutants had defective sporulation, but were rescued extracellularly by wild type cells. All these traits indicate that the encA and encF mutants are likely to be tan-phase-locked, and encapsulin has a close relationship with phase variation in M. xanthus. The encA and encF genes are localized in the same gene cluster, encBAEFG (MXAN_3557~MXAN_3553). Unlike the encA and encF genes, deletion of other genes in the cluster did not show tan-phase-locked phenotype.
Assuntos
Proteínas de Bactérias/metabolismo , Myxococcus xanthus/crescimento & desenvolvimento , Myxococcus xanthus/genética , Proteínas de Bactérias/genética , Cor , Deleção de Genes , Macrolídeos/metabolismo , Metaloproteases/genética , Metaloproteases/metabolismo , Mutação , Myxococcus xanthus/metabolismo , Fenótipo , Polissacarídeos Bacterianos/biossíntese , Xantenos/metabolismoRESUMO
DKxanthenes are a class of yellow secondary metabolites produced by myxobacterial genera Myxococcus and Stigmatella. We identified a putative 49.5 kb DKxanthene biosynthetic gene cluster from Myxococcus stipitatus DSM 14675 by genomic sequence and mutational analysis. The cluster was comprisedof 15 genes (MYSTI_06004-MYSTI_06018) encoding polyketide synthases, non-ribosomal peptide synthases, and proteins with unknown functions. Disruption of the genes by plasmid insertion resulted in defects in the production of yellow pigments. High-performance liquid chromatography and liquid chromatography-tandem mass spectrometry analysis indicated that the yellow pigments produced by M. stipitatus DSM 14675 might be noble DKxanthene derivatives. M. stipitatus did not require DKxanthenes for the formation of heat-resistant viable spores, unlike Myxococcus xanthus. Furthermore, DKxanthenes showed growth inhibitory activity against the fungi Aspergillus niger, Candida albicans, and Rhizopus stolonifer.
Assuntos
Vias Biossintéticas/genética , Família Multigênica/genética , Myxococcus/enzimologia , Myxococcus/genética , Myxococcus/metabolismo , Xantenos/metabolismo , Xantenos/farmacologia , Anti-Infecciosos/química , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Aspergillus niger/efeitos dos fármacos , Aspergillus niger/crescimento & desenvolvimento , Proteínas de Bactérias/genética , Candida albicans/efeitos dos fármacos , Candida albicans/crescimento & desenvolvimento , Carpóforos/efeitos dos fármacos , Genes Bacterianos/genética , Mutação , Myxococcus xanthus/metabolismo , Peptídeo Sintases/genética , Pigmentos Biológicos/genética , Pigmentos Biológicos/metabolismo , Plasmídeos/genética , Policetídeo Sintases/genética , Rhizopus/efeitos dos fármacos , Rhizopus/crescimento & desenvolvimento , Metabolismo Secundário/genética , Análise de Sequência , Esporos/efeitos dos fármacos , Xantenos/químicaRESUMO
Phenalamide is a bioactive secondary metabolite produced by Myxococcus stipitatus. We identified a 56 kb phenalamide biosynthetic gene cluster from M. stipitatus DSM 14675 by genomic sequence analysis and mutational analysis. The cluster is comprised of 12 genes (MYSTI_04318-MYSTI_04329) encoding three pyruvate dehydrogenase subunits, eight polyketide synthase modules, a non-ribosomal peptide synthase module, a hypothetical protein, and a putative flavin adenine dinucleotide-binding protein. Disruption of the MYSTI_04324 or MYSTI_04325 genes by plasmid insertion resulted in a defect in phenalamide production. The organization of the phenalamide biosynthetic modules encoded by the fifth to tenth genes (MYSTI_04320-MYSTI_04325) was very similar to that of the myxalamid biosynthetic gene cluster from Stigmatella aurantiaca Sg a15, as expected from similar backbone structures of the two substances. However, the loading module and the first extension module of the phenalamide synthase encoded by the first to fourth genes (MYSTI_04326-MYSTI_04329) were found only in the phenalamide biosynthetic gene cluster from M. stipitatus DSM 14675.
Assuntos
Amidas/metabolismo , Genes Bacterianos/genética , Família Multigênica/genética , Myxococcus/genética , Myxococcus/metabolismo , Fenóis/metabolismoRESUMO
We report the complete genome sequences of two classical swine fever virus strains (JJ9811 and YI9908). Both belong to subgenotype 3.2. Strain JJ9811 causes mild symptoms and strain YI9908 causes acute symptoms. The sequences were 95.7% homologous at the nucleotide level and 95.6% homologous at the amino acid level.
RESUMO
A new diarylethene-derived photochromic compound, with little cytotoxicity, plasma membrane-permeability, and efficient photoswitchability in cells upon alternative UV and visible light irradiation, was synthesized and applied to live cell imaging.
Assuntos
Etilenos/química , Corantes Fluorescentes/química , Diagnóstico por Imagem/métodos , Etilenos/efeitos da radiação , Corantes Fluorescentes/efeitos da radiação , Células HeLa , Humanos , Luz , Microscopia de FluorescênciaRESUMO
We have used mutational analysis to identify four genes, MXAN3553, MXAN3554, MXAN3555, and MXAN3556, constituting an operon that is essential for normal fruiting body development in Myxococcus xanthus. Deletion of MXAN3553, which encoded a hypothetical protein, resulted in delayed fruiting body development. MXAN3554 was predicted to encode a metallopeptidase, and its deletion caused fruiting body formation to fail. Inactivation of MXAN3555, which encoded a putative NtrC-type response regulator, resulted in delayed aggregation and a severe reduction in sporulation. Fruiting bodies also failed to develop with the deletion of MXAN3556, another gene encoding a hypothetical protein.
Assuntos
Myxococcus xanthus/metabolismo , Óperon , DNA Bacteriano/genética , DNA Bacteriano/metabolismo , Deleção de Genes , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Metaloproteases/deficiência , Metaloproteases/genética , Myxococcus xanthus/fisiologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de Proteína , Homologia de Sequência de Aminoácidos , Esporos Bacterianos/genética , Esporos Bacterianos/metabolismo , Fatores de Transcrição/deficiência , Fatores de Transcrição/genéticaRESUMO
Epothilone and its analogs are a potent new class of anticancer compounds produced by myxobacteria. Thus, in an effort to identify new myxobacterial strains producing epothilone and its analogs, cellulose-degrading myxobacteria were isolated from Korean soils, and 13 strains carrying epothilone biosynthetic gene homologs were screened using a polymerase chain reaction. A migration assay revealed that Sorangium cellulosum KYC3013, 3016, 3017, and 3018 all produced microtubule-stabilizing compounds, and an LCMS/ MS analysis showed that S. cellulosum KYC3013 synthesized epothilone A.
