RESUMO
As an industrial bacterium, Bacillus licheniformis DW2 produces bacitracin which is an important antibiotic for many pathogenic microorganisms. Our previous study showed AbrB-knockout could significantly increase the production of bacitracin. Accordingly, it was meaningful to understand its genome features, expression differences between wild and AbrB-knockout (ΔAbrB) strains, and the regulation of bacitracin biosynthesis. Here, we sequenced, de novo assembled and annotated its genome, and also sequenced the transcriptomes in three growth phases. The genome of DW2 contained a DNA molecule of 4,468,952 bp with 45.93% GC content and 4,717 protein coding genes. The transcriptome reads were mapped to the assembled genome, and obtained 4,102â¼4,536 expressed genes from different samples. We investigated transcription changes in B. licheniformis DW2 and showed that ΔAbrB caused hundreds of genes up-regulation and down-regulation in different growth phases. We identified a complete bacitracin synthetase gene cluster, including the location and length of bacABC, bcrABC, and bacT, as well as their arrangement. The gene cluster bcrABC were significantly up-regulated in ΔAbrB strain, which supported the hypothesis in previous study of bcrABC transporting bacitracin out of the cell to avoid self-intoxication, and was consistent with the previous experimental result that ΔAbrB could yield more bacitracin. This study provided a high quality reference genome for B. licheniformis DW2, and the transcriptome data depicted global alterations across two strains and three phases offered an understanding of AbrB regulation and bacitracin biosynthesis through gene expression.
RESUMO
The updated genome of Bacillus licheniformis WX-02 comprises a circular chromosome of 4286821 base-pairs containing 4512 protein-coding genes. We applied strand-specific RNA-sequencing to explore the transcriptome profiles of B. licheniformis WX-02 under normal and high-salt conditions (NaCl 6%). We identified 2381 co-expressed gene pairs constituting 871 operon structures. In addition, 1169 antisense transcripts and 90 small RNAs were detected. Systematic comparison of differentially expressed genes under different conditions revealed that genes involved in multiple functions were significantly repressed in long-term high salt adaptation process. Genes related to promotion of glutamic acid synthesis were activated by 6% NaCl, potentially explaining the high yield of γ-PGA under salt condition. This study will be useful for the optimization of crucial metabolic activities in this bacterium.
Assuntos
Bacillus/genética , Perfilação da Expressão Gênica , Genômica , Anotação de Sequência Molecular , Bacillus/efeitos dos fármacos , Bacillus/metabolismo , Bacillus/fisiologia , DNA Intergênico/genética , Genes Bacterianos/genética , Ácido Poliglutâmico/análogos & derivados , Ácido Poliglutâmico/biossíntese , RNA Antissenso/genética , RNA Bacteriano/genética , Sais/farmacologia , Análise de Sequência de RNA , Estresse Fisiológico/efeitos dos fármacos , Estresse Fisiológico/genéticaRESUMO
Insecticidal crystal protein gene cry1C which is highly toxic to Spodoptera exigua was cloned into an integrative vector pBMB-F7E, which was derived from Bacillus thuringiensis transposon Tn4430. The recombinant integrative plasmid pBMB-FLC harboring the cry1C gene was gained and transformed into a wild-type Bt strain YBT803-1. A transformant BMB803-A was obtained, and grown at 46 degrees C for about 120 generations, From which three recombinants with cry1C gene integrating into the chromosome were achieved at a frequency of approximately 3.4 x 10(-5). Southern blotting revealed that the integration occurred in different sites of the chromosome. The integrated cry1C were expressed effectively. The results of bioassays showed that the toxicity of recombinants BMB803-X and BMB803-Z against Plutella xylostella were similar to that of strain YBT803-1, and their toxicity to Spodoptera exigua were higher than that of strain YBT803-1.
Assuntos
Bacillus thuringiensis/genética , Proteínas de Bactérias/genética , Toxinas Bacterianas , Endotoxinas/genética , Vetores Genéticos/genética , Animais , Bacillus thuringiensis/crescimento & desenvolvimento , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/metabolismo , DNA Bacteriano/genética , DNA Bacteriano/metabolismo , Desoxirribonucleases de Sítio Específico do Tipo II/metabolismo , Endotoxinas/metabolismo , Proteínas Hemolisinas , Microscopia Eletrônica , Controle Biológico de Vetores/métodos , Spodoptera/microbiologia , Esporos Bacterianos/genética , Esporos Bacterianos/ultraestrutura , Transformação GenéticaRESUMO
Validamycin A, a main component of the antibiotic validamycin complex, which is widely used to control sheath blight disease of rice plants, can be determined by capillary zone electrophoresis with indirect UV detection. The influence of various separation conditions including background electrolyte and modifier concentration, pH, and voltage was investigated. By using 10 mM aminopyrine-2 mM ethylenediaminetetraacetic acid at pH 5.2 as the carrier electrolyte, high efficiency separation of validamycin A was achieved with the number of theoretical plates up to 350000 plates/m. The linear range was across 3 orders of magnitude. The relative standard deviations for migration times and peak areas were less than 0.5 and 3.0%, respectively. The limit of detection for validamycin A was 1.0 microg/mL. The average recoveries ranged from 103.0 to 104.8%. This method has many advantages as compared with high-performance liquid chromatography and micellar electrokinetic capillary chromatography in the determination of commercial formulations.
