A 1 539 by squalene synthase (AaSQS) cDNA was cloned from a high-yield Artemisia annua L. strain 001 by reverse transcription-polymerise chain reaction (RT-PCR). The amino acid sequence of AaSQS is 70%, 77%, 44% and 3...A 1 539 by squalene synthase (AaSQS) cDNA was cloned from a high-yield Artemisia annua L. strain 001 by reverse transcription-polymerise chain reaction (RT-PCR). The amino acid sequence of AaSQS is 70%, 77%, 44% and 39%a identical to that of squalene synthases from Arabidopsis thaliana, tobacco, human and yeast, respectively. The AaSQS genomic DNA has a complex organization containing 14 exons and 13 introns. Full-length or C-terminal truncated cDNA was subcloned into prokaryotic expression vector pET30a and the constructed plasmid was introduced to Escherichia coli strain BL21 (DE3) for induced overexpression. No squalene synthase protein with expected molecular mass was observed in E. cola containing the putative full-length squalene synthase cDNA, however, overexpression in E. coli was achieved by truncating 30 amino acids of hydrophobic region at the carboxy terminus.展开更多
Application of high-speed centrifugation and high-performance liquid chro- matography to separation and purification obtained a new type of natural antibacteri- al substance from Escherichia co/i cell. Against Staphy/...Application of high-speed centrifugation and high-performance liquid chro- matography to separation and purification obtained a new type of natural antibacteri- al substance from Escherichia co/i cell. Against Staphy/ococcus aureus, Escherichia coli, Pasteurella multocida, Streptococcus, Pseudomonas, solanacearum the minimal inhibitory concentration （MIC） was 2.5, 5, 0.625 iJg/ml, 0.625 and 1.25 g/ml, the minimum bactericidal concentration （MBC） was 5, 5, 1.25, 2.5, 2.5 g/ml, respectively. Composition identification of chemical method and mass spectrometry shows that the antibacterial active substance alkaloids; and the safety evaluation on the model plant Arabidopsis shows that the antibacterial active substance had no inhibitory and adverse effects on the growth and development of plants. The experimental results show that the antibacterial active substance is a broad-spectrum, high efficiency, safe antibacterial natural product, with the prospect of development and utilization of alternative antibiotics.展开更多
AIM： To compare the effectiveness of triple, standard quadruple and ampicillin-sulbactam-based quadruple therapies for Hpylori eradication in a comparative three-armed randomized clinical trial. METHODS： A total of ...AIM： To compare the effectiveness of triple, standard quadruple and ampicillin-sulbactam-based quadruple therapies for Hpylori eradication in a comparative three-armed randomized clinical trial. METHODS： A total of 360 H pylori-positive patients suffering from dyspepsia and aging 24-79 years with a median age of 42 years were enrolled in the study and randomly allocated into the following three groups： group A （n = 120） received a standard 1-wk triple therapy （20 mg omeprazole b.i.d., 1000 mg amoxicillin b.i.d., 500 mg clarithromycin b.i.d.）, group B （n = 120） received a 10-d standard quadruple therapy （20 mg omeprazole b.i.d., 1000 mg amoxicillin b.i.d., 240 mg colloidal bismuth subcitrate b.i.d., and 500 mg metronidazole b.i.d.）, group C （n = 120） received the new protocol, i.e. 375 mg sultamicillin （225 mg ampicillin plus 150 mg sulbactam） b.i.d. （before breakfast and dinner）, instead of amoxicillin in the standard quadruple therapy for the same duration. Chi-square test with the consideration of P 〈 0.05 as significant was used to compare the eradication rates by intention-to-treat and per-protocol analyses in the three groups.RESULTS： The per-protocol eradication rate was 91.81% （101 patients from a total of 110） in group A, 85.84% （97 patients from a total of 113） in group B, and 92.85% （104 patients from a total of 112） in group C. The intention-to-treat eradication rate was 84.17% in group A, 80.83% in group B, and 86.67% in group C. The new protocol yielded the highest eradication rates by both per-protocol and intention-to-treat analyses followed by the standard triple and quadruple regimens, respectively. However, the differences were not statistically significant between the three groups. CONCLUSION： The results of this study provide further support for the equivalence of triple and quadruple therapies in terms of effectiveness, compliance and sideeffect profile when administered as first-line treatment for H pylori infection. Moreover, the new protocol using ampicillin-sulbactam instead of amoxicillin in the quadruple regimen is a suitable first-line alternative to be used in regions with amoxicillin-resistant Hpylori strains.展开更多
AIM： To assess the safety of Bifidobacterium/ongum （B. longum） JDM301 based on complete genome sequences. METHODS： The complete genome sequences of JDM301 were determined using the GS 20 system. Putative virulence...AIM： To assess the safety of Bifidobacterium/ongum （B. longum） JDM301 based on complete genome sequences. METHODS： The complete genome sequences of JDM301 were determined using the GS 20 system. Putative virulence factors, putative antibiotic resis- tance genes and genes encoding enzymes respon- sible for harmful metabolites were identified by blast with virulence factors database, antibiotic resistance genes database and genes associated with harmful metabolites in previous reports. Minimum inhibitory concentration of 16 common antimicrobial agents was evaluated by E-test RESULTS： JDM301 was shown to contain 36 genes as- sociated with antibiotic resistance, 5 enzymes related to harmful metabolites and 162 nonspecific virulence fac- tors mainly associated with transcriptional regulation, adhesion, sugar and amino acid transport. B. longum JDM301 was intrinsically resistant to ciprofloxacin, ami- kacin, gentamicin and streptomycin and susceptible to vancomycin, amoxicillin, cephalothin, chloramphenicol, erythromycin, ampicillin, cefotaxime, rifampicin, imi- penem and trimethoprim-sulphamethoxazol. JDM301 was moderately resistant to bacitracin, while an earlier study showed that bifidobacteria were susceptible to this antibiotic. A tetracycline resistance gene with the risk of transfer was found in JDM301, which needs to be experimentally validated. CONCLUSION： The safety assessment of JDM301 using information derived from complete bacterial ge- nome will contribute to a wider and deeper insight into the safety of probiotic bacteria.展开更多
All previously reported bacterial species which are capable of lysing harmful algae have been isolated from coastal environments in which harmful algae blooms have occurred. Due to the low concentration of alga-lysing...All previously reported bacterial species which are capable of lysing harmful algae have been isolated from coastal environments in which harmful algae blooms have occurred. Due to the low concentration of alga-lysing bacteria in an algal bloom, it is difficult to isolate the alga-lysing bacteria by existing methods. In this paper, two algae-lysing bacterial strains, P01 and P03, have been isolated from a biosystem immobilized on a sponge that was highly effective in removing algae and microcystins. Their lysing modes and effects on Microcystis aeruginosa have been studied. The results show that the degradation processes of these two strains for M. aeruginosa accorded with a first-order reaction model when the chlorophylla concentration was in the range from 0 to 1000 μgL-1. The degradation rate constants were 0.1067, 0.1274 and 0.2792 for P01 and0.0683, 0.0744 and 0.028 97 for P03, when the bacterial densities were 8.6 × 105, 8.6 × 106 and 8.6 × 107cells mL-1 respectively. Moreover, the two bacterial strains had favourable lytic effects not only on M. aeruginosa , but also on Chlorella and Scene-desmus. Their lytic effect on M. aeruginosa did not require physical cell to cell contact, but proceeded by the production of an extracellular product. The bacterial strains were identified as Bacillus species by PCR amplification of the 16S rRNA gene, BLAST analysis, and comparison with sequences in the GenBank nucleotide database.展开更多
文摘A 1 539 by squalene synthase (AaSQS) cDNA was cloned from a high-yield Artemisia annua L. strain 001 by reverse transcription-polymerise chain reaction (RT-PCR). The amino acid sequence of AaSQS is 70%, 77%, 44% and 39%a identical to that of squalene synthases from Arabidopsis thaliana, tobacco, human and yeast, respectively. The AaSQS genomic DNA has a complex organization containing 14 exons and 13 introns. Full-length or C-terminal truncated cDNA was subcloned into prokaryotic expression vector pET30a and the constructed plasmid was introduced to Escherichia coli strain BL21 (DE3) for induced overexpression. No squalene synthase protein with expected molecular mass was observed in E. cola containing the putative full-length squalene synthase cDNA, however, overexpression in E. coli was achieved by truncating 30 amino acids of hydrophobic region at the carboxy terminus.
基金Supported by Guangdong Scientific and Technological Bureau(2012B020401012)~~
文摘Application of high-speed centrifugation and high-performance liquid chro- matography to separation and purification obtained a new type of natural antibacteri- al substance from Escherichia co/i cell. Against Staphy/ococcus aureus, Escherichia coli, Pasteurella multocida, Streptococcus, Pseudomonas, solanacearum the minimal inhibitory concentration （MIC） was 2.5, 5, 0.625 iJg/ml, 0.625 and 1.25 g/ml, the minimum bactericidal concentration （MBC） was 5, 5, 1.25, 2.5, 2.5 g/ml, respectively. Composition identification of chemical method and mass spectrometry shows that the antibacterial active substance alkaloids; and the safety evaluation on the model plant Arabidopsis shows that the antibacterial active substance had no inhibitory and adverse effects on the growth and development of plants. The experimental results show that the antibacterial active substance is a broad-spectrum, high efficiency, safe antibacterial natural product, with the prospect of development and utilization of alternative antibiotics.
文摘AIM： To compare the effectiveness of triple, standard quadruple and ampicillin-sulbactam-based quadruple therapies for Hpylori eradication in a comparative three-armed randomized clinical trial. METHODS： A total of 360 H pylori-positive patients suffering from dyspepsia and aging 24-79 years with a median age of 42 years were enrolled in the study and randomly allocated into the following three groups： group A （n = 120） received a standard 1-wk triple therapy （20 mg omeprazole b.i.d., 1000 mg amoxicillin b.i.d., 500 mg clarithromycin b.i.d.）, group B （n = 120） received a 10-d standard quadruple therapy （20 mg omeprazole b.i.d., 1000 mg amoxicillin b.i.d., 240 mg colloidal bismuth subcitrate b.i.d., and 500 mg metronidazole b.i.d.）, group C （n = 120） received the new protocol, i.e. 375 mg sultamicillin （225 mg ampicillin plus 150 mg sulbactam） b.i.d. （before breakfast and dinner）, instead of amoxicillin in the standard quadruple therapy for the same duration. Chi-square test with the consideration of P 〈 0.05 as significant was used to compare the eradication rates by intention-to-treat and per-protocol analyses in the three groups.RESULTS： The per-protocol eradication rate was 91.81% （101 patients from a total of 110） in group A, 85.84% （97 patients from a total of 113） in group B, and 92.85% （104 patients from a total of 112） in group C. The intention-to-treat eradication rate was 84.17% in group A, 80.83% in group B, and 86.67% in group C. The new protocol yielded the highest eradication rates by both per-protocol and intention-to-treat analyses followed by the standard triple and quadruple regimens, respectively. However, the differences were not statistically significant between the three groups. CONCLUSION： The results of this study provide further support for the equivalence of triple and quadruple therapies in terms of effectiveness, compliance and sideeffect profile when administered as first-line treatment for H pylori infection. Moreover, the new protocol using ampicillin-sulbactam instead of amoxicillin in the quadruple regimen is a suitable first-line alternative to be used in regions with amoxicillin-resistant Hpylori strains.
基金Supported by The National Key Program for Infectious Diseases of China,No. 2008ZX10004 and 2009ZX10004the Program of Shanghai Subject Chief Scientist,No. 09XD1402700+1 种基金the Program of Shanghai Research and Development,No. 10JC1408200a China Partnering Award from the Biotechnology and Biological Sciences Research Council,United Kingdom
文摘AIM： To assess the safety of Bifidobacterium/ongum （B. longum） JDM301 based on complete genome sequences. METHODS： The complete genome sequences of JDM301 were determined using the GS 20 system. Putative virulence factors, putative antibiotic resis- tance genes and genes encoding enzymes respon- sible for harmful metabolites were identified by blast with virulence factors database, antibiotic resistance genes database and genes associated with harmful metabolites in previous reports. Minimum inhibitory concentration of 16 common antimicrobial agents was evaluated by E-test RESULTS： JDM301 was shown to contain 36 genes as- sociated with antibiotic resistance, 5 enzymes related to harmful metabolites and 162 nonspecific virulence fac- tors mainly associated with transcriptional regulation, adhesion, sugar and amino acid transport. B. longum JDM301 was intrinsically resistant to ciprofloxacin, ami- kacin, gentamicin and streptomycin and susceptible to vancomycin, amoxicillin, cephalothin, chloramphenicol, erythromycin, ampicillin, cefotaxime, rifampicin, imi- penem and trimethoprim-sulphamethoxazol. JDM301 was moderately resistant to bacitracin, while an earlier study showed that bifidobacteria were susceptible to this antibiotic. A tetracycline resistance gene with the risk of transfer was found in JDM301, which needs to be experimentally validated. CONCLUSION： The safety assessment of JDM301 using information derived from complete bacterial ge- nome will contribute to a wider and deeper insight into the safety of probiotic bacteria.
基金This study was supported by the Sino Japan Science Cooperative Program （Grant No.003250103） Special Funds for PhD Research Station of University （Grant No. 20020422045）Science Foundation of Shandong Province （Grant No. Z2003B01 ）.
文摘All previously reported bacterial species which are capable of lysing harmful algae have been isolated from coastal environments in which harmful algae blooms have occurred. Due to the low concentration of alga-lysing bacteria in an algal bloom, it is difficult to isolate the alga-lysing bacteria by existing methods. In this paper, two algae-lysing bacterial strains, P01 and P03, have been isolated from a biosystem immobilized on a sponge that was highly effective in removing algae and microcystins. Their lysing modes and effects on Microcystis aeruginosa have been studied. The results show that the degradation processes of these two strains for M. aeruginosa accorded with a first-order reaction model when the chlorophylla concentration was in the range from 0 to 1000 μgL-1. The degradation rate constants were 0.1067, 0.1274 and 0.2792 for P01 and0.0683, 0.0744 and 0.028 97 for P03, when the bacterial densities were 8.6 × 105, 8.6 × 106 and 8.6 × 107cells mL-1 respectively. Moreover, the two bacterial strains had favourable lytic effects not only on M. aeruginosa , but also on Chlorella and Scene-desmus. Their lytic effect on M. aeruginosa did not require physical cell to cell contact, but proceeded by the production of an extracellular product. The bacterial strains were identified as Bacillus species by PCR amplification of the 16S rRNA gene, BLAST analysis, and comparison with sequences in the GenBank nucleotide database.
