| Denitrification is a process that nitrogen oxides (NO3- or NO2-) were reduced to produce gaseous nitrogen (N2O or N2) by four kinds of reductases in bacteria. The nos cluster encode N2OR, which could reduce N2O to N2. Nowdays, few researches focused on the nos cluster of Bacillus cereus. Stduying the nos cluster of Bacillus cereus is significant to understand the molecular mechanism of N2OR. Microbial genomics sequencing technology is rapidly developed, which can help us to learn denitrification in genomics. Genomics offered a new comprehensive and systematic way to study denitrification.To explore the characteristic of nos cluster genes of Bacillus cereus HS-N10, a series of nos cluster genes were aligned in different genuses. According to the conserved region of the genes, the primers of HS-N10 nos cluster genes were designed, the conserved sequences of HS-N10 nos cluster genes were cloned. According to the conserved sequences, the primers were designed; Through PCR and gene walking, the whole nosZ sequence was cloned, which was the structure gene of N2OR. The results showed that the sequence of nosZ ORF contained 1914bp and the partial nucleotide sequences of nosR?nosD?nosF contained 1749 bp,946 bp,495 bp, respectively. Meanwhile, some bioinformatic analysis of HS-N10 nos cluster were taken through online databases and tools. By the BLASTIN analysis, nosZ and nosD sequences of HS-N10 were similar to the genes of Pseudomonas stutzeri; while the sequences of nosR and nosF were similar to the genes of Achromobacter cycloclastes. The phylogenetic trees which was based on the proteins HS-N10 nos cluster encoding showed some results about the relationship in genetic:HS-N10 NosZ was close to Pseudomonas.sp NosZ, and it was far from with ?-proteobacteria and Gram-positive bacterium; about NosR, HS-N10 was close to Achromobacter cycloclastes, which belonged to P-proteobacteria; HS-N10 NosD had the closest relationship with Pseudomonas stutzeri NosD; and NosF of HS-N10 was considered close to ?-proteobacteria. The homology modeling methods and sequence homology analysis of nosZ suggested that in the C terminal, the region of 580-628 amino acid residues was the CuA centre; H582 and H625 were bond to Cu+ in the CuA centre. In the N terminal, the Cuz centre was from 128 amino acid residue to 493 amino acid residue; while H128?H129?H177?H325?H381?H432?H493 was bond to Cu+ in the Cuz centre.Researchers were quite familiar with denitrification through about forty years studying. So far, the research on denitrification process in the whole genome has rarely reported. In this work, the genomes of two aerobic denitrifying bacteria (HS-N03 and HS-Nlll) were extracted and detected, and the genomes of these two bacteria were extracted and detected. The gene scanning was taken by shanghai majorbio bio-pharm technology co., ltd. The genome information of HS-N03 showed:the total length was 10583491bp; while the average GC content was 54.20%; the bacteria contained 9418 ORFs, which occupied 81.8% of the whole genome. The genome information of HS-N111 suggested that:the total length was 584209bp; while the average GC content was 55.99%; the bacteria contained 2899 ORFs, which occupied 86.9% of whole genome. GO analysis showed that in genome of HS-N03,5211 ORFs have annotation information, which occupy 55.33% of all ORFs; hile only 2899 ORFs have annotation information, which occupy 65.63% of all ORFs in HS-N111 genome. COG analysis revealed that HS-N03 was enriched in categories of genes involved in amino acid transport and metabolism, function unknown, carbohydrate transport and metabolism. Moreover, HS-N111 was enriched in categories of genes involved in function unknown, amino acid transport and metabolism, transcription, carbohydrate transport and metabolism.The genes related to denitrification in the whole genome were analyzed. The numbers of genes associated with nitrate reductase, nitrite reductase, nitric oxide reductase and nitrous oxide reductase in HS-N03 genome were 60,28,19 and 1, respectively; while amount in HS-N111 were smaller, which were 24,9,8,0, respectively. Meanwhile, inorganic ions transport genes were searched. There were 609 inorganic ions transport genes in HS-N03 genome, among which only 99 genes could be associated with denitrification. Differently, HS-N111 genome had 275 genes related to inorganic ions transport, and 44 genes were denitrifying inorganic ions transport gene. |
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