Pseudoalteromonas sp. SM9913 is a phychrotmphic bacterium isolated from the deep-sea sediment. The genes encoding chaperones DnaJ and DnaK of P. sp. SM9913 were cloned by normal PCR and TAIL - PCR （GenBank accession ...Pseudoalteromonas sp. SM9913 is a phychrotmphic bacterium isolated from the deep-sea sediment. The genes encoding chaperones DnaJ and DnaK of P. sp. SM9913 were cloned by normal PCR and TAIL - PCR （GenBank accession Nos DQ640312, DQ504163 ）. The chaperones DnaJ and DnaK from the strain SM9913 contain such conserved domains as those of many other bacteria, and show some cold-adapted characteristics in their structures when compared with those from psychro-, meso-and themophilic bacteria. It is indicated that chaperones DnaJ and DnaK of P. sp. SM9913 may be adapted to low temperature in deep-sea and function well in assisting folding, assembling and translocation of proteins at low temperature. This research lays a foundation for the further study on the cold-adapted mechanism of chaperones DnaJ and DnaK of cold-adapted microorganisms.展开更多
A recombinant strain, Escherichia coli JM109-AN1, was obtained by constructing of a genomic library of the total DNA of Delftia sp. AN3 in E. coli JM109 and screening for catechol 2,3-dioxygenase activity. This recomb...A recombinant strain, Escherichia coli JM109-AN1, was obtained by constructing of a genomic library of the total DNA of Delftia sp. AN3 in E. coli JM109 and screening for catechol 2,3-dioxygenase activity. This recombinant strain could grow on aniline as sole carbon, nitrogen and energy source. Enzymatic assays revealed that the exogenous genes including aniline dioxygenase （AD） and catechol 2,3-dioxygenase （C230） genes could well express in the recombinant strain with the activities of AD and C230 up to 0.31 U/mg wet cell and 1.92 U/mg crude proteins, respectively. The AD or C23O of strain AN3 could only catalyze aniline or catechol but not any other substituted substrates. This recombinant strain contained a recombinant plasmid, pKC505-AN1, in which a 29.7-kb DNA fragment from Delftia sp. AN3 was inserted. Sequencing and open reading frame （orfs） analysis of this 29.7 kb fragment revealed that it contained at least 27 orfs, among them a gene cluster （consisting of at least 16 genes, named danQTA1A2BRDCEFG1HIJKG2） was responsible for the complete metabolism of aniline to TCA-cycle intermediates. This gene cluster could be divided into two main parts, the upper sequences consisted of 7 genes （danQTA1A2BRD） were predicted to encode a multi-component aniline dioxygenase and a LysR-type regulator, and the central genes （danCEFG1HIJKG2） were expected to encode meta-cleavage pathway enzymes for catechol degradation to TCA-cycle intermediates. Unlike clusters tad from Delftia tsuruhatensis AD9 and tdn from Pseudomonas putida UCC22, in this gene cluster, all the genes were in the same transcriptional direction. There was only one set of C230 gene （danC） and ferredoxin-like protein gene （danD）. The presence of only one set of these two genes and specificity of AD and C230 might be the reason for strain AN3 could only degrade aniline. The products of danQTA1A2BRDC showed 99%-100% identity to those from Delftia acidovorans 7N, and 50%-85% identity to those of tad cluster from D. tsuruhatensis AD9 in amino acid residues. Besides this dan cluster, the 29.7 kb fragment also contained genes encoding the trans-membrane transporter and transposases which might be needed for transposition of the gene cluster. Pulsed-field gel electrophoresis （PFGE） and plasmid curing experiments suggested that the dan cluster might be encoded on the chromosome of strain AN3. The GenBank accession number for the dan cluster of Delftia sp. AN3 is DQ661649.展开更多
According to the known sequence of iron stress-induced gene (isiAB operon), wecloned its 1. 5 kb fragment by PCR, and used this Fragment as integration homologous fragment. Afterseveral steps of subcloning donor DNA i...According to the known sequence of iron stress-induced gene (isiAB operon), wecloned its 1. 5 kb fragment by PCR, and used this Fragment as integration homologous fragment. Afterseveral steps of subcloning donor DNA into the isiAB fragment, a donor plasmid pZL which could be inte-grated into the chromosomal DNA of Synechococcus sp. PCC7942 was constructed. In order to express theheterologous gene at a high level through the integration platform system, we constructed the donor DNAby the following steps. We cloned the strong promoter (240 bp) of heat shock gene groESL operon fromSynechococcus sp. PCC7942 by PCR. Then subcloned the multiple cloning sites (MCS), rbcS polyA intothe downstream of the groESL promoter. The kanamycin resistance gene, as the marker gene, was alsosubcloned into the donor DNA. Thus, in the donor plasmid pZL, the integration homologous fragment andseveral expression elements, such as groESL promoter, MCS, rbcS polyA teminator and kanamycin re-sistance gene, were all included.After naturally transformed and introduced the donor plasmid pZL into Synechococcus sp. PCC7942,as in the pZL, the donor DNA sequence is flanked by two DNA fragments (0.4 kb and 0.7 kb) homolo-gous to the isiAB fragment of Synechococcus sp. PCC7942, the homologous DNA can recombine with thechromosomal DNA. After screening by kanamycin, the transformants which integrated the heterologousDNA were selected. The efficiency of transformation is about 1×10-6. By southem blot analysis, it wasconfirmed that the donor DNA had been integrated into the chromosomal DNA of Synechococcus sp.PCC7942, located on the site of the isiAB gene, and can be replicated with the chromosomal DNA.展开更多
Cyt b gene of North Sulawesi Tarsius sp., T. tumpara, T. sangirensis and T. tarsier (T. spectrum) had been partially sequenced. The homologous sequence of three groups had been compared to describe the phylogenetic po...Cyt b gene of North Sulawesi Tarsius sp., T. tumpara, T. sangirensis and T. tarsier (T. spectrum) had been partially sequenced. The homologous sequence of three groups had been compared to describe the phylogenetic position among them, as well as several other species accessed from the Genbank. Total DNA extracted from the muscular tissue had been obtained through tail cut sampling using the innuPREP DNA micro kit, and amplified using a pair of universal primer, L14841 and H15149. The size of the cyt b gene sequence amplified was 307 bp long. Sequence aligned using CLUSTAL-X program and diversity analysis were done using version 5.2.2. MEGA5 program. Genetic distance had been calculated by Tamura 3 parameter method and phylogenetic tree had been built using Neighbor-Joining and Maximum Likelihood methods. Genetic distance based on cyt b gene nucleotide was found from 0 to 0.240 with an average of 0.080. The phylogenetic tree constructed by Neighbor Joining and Maximum Likelihood methods indicated that T. tarsier, T. sangirensis and T. tumpara were closely related with Tarsius tarsier-complex, and distantly related with Cephalopachus bancanus and Carlito syrichta. The genetic distance and the phylogenetic tree had been constructed on the base of partial cyt b gene sequence of T. tarsier, T. sangirensis, T. tumpara and 5 other tarsier species and their accession. Those results are consistent with taxonomy based on morphology and vocal acoustic form.展开更多
Puccinia striiformis f. sp. tritici (Pst) is one of the pathogenic fungi on wheat, caused stripe rust that is a great threat for wheat production all over the world. Intensive efforts have been made to study genetics ...Puccinia striiformis f. sp. tritici (Pst) is one of the pathogenic fungi on wheat, caused stripe rust that is a great threat for wheat production all over the world. Intensive efforts have been made to study genetics of wheat resistance to this disease, but few on avirulence of the pathogen due mainly to the nature of obligate biotrophism and the lack of systems for studying its genetics and molecular manipulations. To overcome these limitations, a natural Pst population comprising 352 isolates representative of a diverse virulence spectrum was genotyped using 97 secreted protein-single nucleotide polymorphism (SP-SNP) markers to identify candidate avirulence genes using association analysis. Among avirulence genes corresponding to 19 resistance genes, significantly associated SP-SNP markers were detected for avirulence genes AvYr1, AvYr2, AvYr6, AvYr7, AvYr8, AvYr44, AvYrExp2, AvYrSP, and AvYrTye. These results indicate that association analysis can be used to identify markers for avirulence genes. This study has laid the foundation for developing more SP-SNPs for mapping avirulence genes using segregating populations that can be generated through sexual reproduction on alternate hosts of the pathogen.展开更多
B-3 exopolysaccharide is extracted from the Antarctic psychrophilic bacterium Psychrobacter sp. B-3. We have previously shown that it activates macrophages and affects their immunoregulatory activities. To determine w...B-3 exopolysaccharide is extracted from the Antarctic psychrophilic bacterium Psychrobacter sp. B-3. We have previously shown that it activates macrophages and affects their immunoregulatory activities. To determine what genes are affected during this process, we detected the genes differentially expressed in cells of RAW264.7 macrophages treated with B-3 exopolysaccharide by transcriptomic analysis. B-3 exopolysaccharide treatment caused differential expression of 420 genes, of which 178 were up-regulated and 242 were down-regulated. These genes were shown to be involved in many aspects of cell function, mainly metabolism and immunity. Genes were enriched in multiple immune-related pathways, and the most significantly enriched genes were involved in antigen processing and presentation pathways. The pathway in which differentially expressed genes were the most significantly enriched was the metabolic pathway; specifically, the expression of many metabolic enzyme genes was altered by B-3 exopolysaccharide treatment. Additionally, the genes involved in metabolisms of amino acids, carbohydrates, lipids and nucleotides, varied to certain degrees. B-3 exopolysaccharide, therefore, appears to directly affect the immune function of RAW264.7 macrophages as an immunostimulant, or to indirectly change intracellular metabolism. This is the first study to determine the effect of an Antarctic psychrophilic bacterial exopolysaccharide on RAW264.7 macrophages. Our findings provide an important reference for research into the regulation of macrophage immune function by different polysaccharides.展开更多
基金The work was supported by the Hi-Tech Research and Development Program of China under contract Nos 2006AA09Z414 and 2007AA091903；the China Ocean Mineral Resources R ＆ D Association under contract No. DYXM - 115 - 02 - 2 - 6；the National Natural Science Foundation of China under contract No. Z2004D02；the Natural Science Foundation of Shandong Province of China under contract No. Z2004D02；the Foundation for Young Excellent Scientists in Shandong Province of China under contract No. 2006BS02002；the Program for New Century Excellent Talents in University under contract No. NCET - 06 - 0578.
文摘Pseudoalteromonas sp. SM9913 is a phychrotmphic bacterium isolated from the deep-sea sediment. The genes encoding chaperones DnaJ and DnaK of P. sp. SM9913 were cloned by normal PCR and TAIL - PCR （GenBank accession Nos DQ640312, DQ504163 ）. The chaperones DnaJ and DnaK from the strain SM9913 contain such conserved domains as those of many other bacteria, and show some cold-adapted characteristics in their structures when compared with those from psychro-, meso-and themophilic bacteria. It is indicated that chaperones DnaJ and DnaK of P. sp. SM9913 may be adapted to low temperature in deep-sea and function well in assisting folding, assembling and translocation of proteins at low temperature. This research lays a foundation for the further study on the cold-adapted mechanism of chaperones DnaJ and DnaK of cold-adapted microorganisms.
文摘A recombinant strain, Escherichia coli JM109-AN1, was obtained by constructing of a genomic library of the total DNA of Delftia sp. AN3 in E. coli JM109 and screening for catechol 2,3-dioxygenase activity. This recombinant strain could grow on aniline as sole carbon, nitrogen and energy source. Enzymatic assays revealed that the exogenous genes including aniline dioxygenase （AD） and catechol 2,3-dioxygenase （C230） genes could well express in the recombinant strain with the activities of AD and C230 up to 0.31 U/mg wet cell and 1.92 U/mg crude proteins, respectively. The AD or C23O of strain AN3 could only catalyze aniline or catechol but not any other substituted substrates. This recombinant strain contained a recombinant plasmid, pKC505-AN1, in which a 29.7-kb DNA fragment from Delftia sp. AN3 was inserted. Sequencing and open reading frame （orfs） analysis of this 29.7 kb fragment revealed that it contained at least 27 orfs, among them a gene cluster （consisting of at least 16 genes, named danQTA1A2BRDCEFG1HIJKG2） was responsible for the complete metabolism of aniline to TCA-cycle intermediates. This gene cluster could be divided into two main parts, the upper sequences consisted of 7 genes （danQTA1A2BRD） were predicted to encode a multi-component aniline dioxygenase and a LysR-type regulator, and the central genes （danCEFG1HIJKG2） were expected to encode meta-cleavage pathway enzymes for catechol degradation to TCA-cycle intermediates. Unlike clusters tad from Delftia tsuruhatensis AD9 and tdn from Pseudomonas putida UCC22, in this gene cluster, all the genes were in the same transcriptional direction. There was only one set of C230 gene （danC） and ferredoxin-like protein gene （danD）. The presence of only one set of these two genes and specificity of AD and C230 might be the reason for strain AN3 could only degrade aniline. The products of danQTA1A2BRDC showed 99%-100% identity to those from Delftia acidovorans 7N, and 50%-85% identity to those of tad cluster from D. tsuruhatensis AD9 in amino acid residues. Besides this dan cluster, the 29.7 kb fragment also contained genes encoding the trans-membrane transporter and transposases which might be needed for transposition of the gene cluster. Pulsed-field gel electrophoresis （PFGE） and plasmid curing experiments suggested that the dan cluster might be encoded on the chromosome of strain AN3. The GenBank accession number for the dan cluster of Delftia sp. AN3 is DQ661649.
文摘According to the known sequence of iron stress-induced gene (isiAB operon), wecloned its 1. 5 kb fragment by PCR, and used this Fragment as integration homologous fragment. Afterseveral steps of subcloning donor DNA into the isiAB fragment, a donor plasmid pZL which could be inte-grated into the chromosomal DNA of Synechococcus sp. PCC7942 was constructed. In order to express theheterologous gene at a high level through the integration platform system, we constructed the donor DNAby the following steps. We cloned the strong promoter (240 bp) of heat shock gene groESL operon fromSynechococcus sp. PCC7942 by PCR. Then subcloned the multiple cloning sites (MCS), rbcS polyA intothe downstream of the groESL promoter. The kanamycin resistance gene, as the marker gene, was alsosubcloned into the donor DNA. Thus, in the donor plasmid pZL, the integration homologous fragment andseveral expression elements, such as groESL promoter, MCS, rbcS polyA teminator and kanamycin re-sistance gene, were all included.After naturally transformed and introduced the donor plasmid pZL into Synechococcus sp. PCC7942,as in the pZL, the donor DNA sequence is flanked by two DNA fragments (0.4 kb and 0.7 kb) homolo-gous to the isiAB fragment of Synechococcus sp. PCC7942, the homologous DNA can recombine with thechromosomal DNA. After screening by kanamycin, the transformants which integrated the heterologousDNA were selected. The efficiency of transformation is about 1×10-6. By southem blot analysis, it wasconfirmed that the donor DNA had been integrated into the chromosomal DNA of Synechococcus sp.PCC7942, located on the site of the isiAB gene, and can be replicated with the chromosomal DNA.
文摘Cyt b gene of North Sulawesi Tarsius sp., T. tumpara, T. sangirensis and T. tarsier (T. spectrum) had been partially sequenced. The homologous sequence of three groups had been compared to describe the phylogenetic position among them, as well as several other species accessed from the Genbank. Total DNA extracted from the muscular tissue had been obtained through tail cut sampling using the innuPREP DNA micro kit, and amplified using a pair of universal primer, L14841 and H15149. The size of the cyt b gene sequence amplified was 307 bp long. Sequence aligned using CLUSTAL-X program and diversity analysis were done using version 5.2.2. MEGA5 program. Genetic distance had been calculated by Tamura 3 parameter method and phylogenetic tree had been built using Neighbor-Joining and Maximum Likelihood methods. Genetic distance based on cyt b gene nucleotide was found from 0 to 0.240 with an average of 0.080. The phylogenetic tree constructed by Neighbor Joining and Maximum Likelihood methods indicated that T. tarsier, T. sangirensis and T. tumpara were closely related with Tarsius tarsier-complex, and distantly related with Cephalopachus bancanus and Carlito syrichta. The genetic distance and the phylogenetic tree had been constructed on the base of partial cyt b gene sequence of T. tarsier, T. sangirensis, T. tumpara and 5 other tarsier species and their accession. Those results are consistent with taxonomy based on morphology and vocal acoustic form.
文摘Puccinia striiformis f. sp. tritici (Pst) is one of the pathogenic fungi on wheat, caused stripe rust that is a great threat for wheat production all over the world. Intensive efforts have been made to study genetics of wheat resistance to this disease, but few on avirulence of the pathogen due mainly to the nature of obligate biotrophism and the lack of systems for studying its genetics and molecular manipulations. To overcome these limitations, a natural Pst population comprising 352 isolates representative of a diverse virulence spectrum was genotyped using 97 secreted protein-single nucleotide polymorphism (SP-SNP) markers to identify candidate avirulence genes using association analysis. Among avirulence genes corresponding to 19 resistance genes, significantly associated SP-SNP markers were detected for avirulence genes AvYr1, AvYr2, AvYr6, AvYr7, AvYr8, AvYr44, AvYrExp2, AvYrSP, and AvYrTye. These results indicate that association analysis can be used to identify markers for avirulence genes. This study has laid the foundation for developing more SP-SNPs for mapping avirulence genes using segregating populations that can be generated through sexual reproduction on alternate hosts of the pathogen.
基金The Important National Science&Technology Specific Projects under contract No.2011ZX8001-003the National Natural Science Fundation of China under contract No.40706053Chinese Polar Environment Comprehensive Investigation&Assessment Programs under contract No.CHINARE2017-01-05
文摘B-3 exopolysaccharide is extracted from the Antarctic psychrophilic bacterium Psychrobacter sp. B-3. We have previously shown that it activates macrophages and affects their immunoregulatory activities. To determine what genes are affected during this process, we detected the genes differentially expressed in cells of RAW264.7 macrophages treated with B-3 exopolysaccharide by transcriptomic analysis. B-3 exopolysaccharide treatment caused differential expression of 420 genes, of which 178 were up-regulated and 242 were down-regulated. These genes were shown to be involved in many aspects of cell function, mainly metabolism and immunity. Genes were enriched in multiple immune-related pathways, and the most significantly enriched genes were involved in antigen processing and presentation pathways. The pathway in which differentially expressed genes were the most significantly enriched was the metabolic pathway; specifically, the expression of many metabolic enzyme genes was altered by B-3 exopolysaccharide treatment. Additionally, the genes involved in metabolisms of amino acids, carbohydrates, lipids and nucleotides, varied to certain degrees. B-3 exopolysaccharide, therefore, appears to directly affect the immune function of RAW264.7 macrophages as an immunostimulant, or to indirectly change intracellular metabolism. This is the first study to determine the effect of an Antarctic psychrophilic bacterial exopolysaccharide on RAW264.7 macrophages. Our findings provide an important reference for research into the regulation of macrophage immune function by different polysaccharides.
