Twenty-seven antarctic bacteria producing extracellular polysaccharide （EPS） were selected from 57 strains by staining technology. The effects of major environmental factors on the growth and EPS production of Pseud...Twenty-seven antarctic bacteria producing extracellular polysaccharide （EPS） were selected from 57 strains by staining technology. The effects of major environmental factors on the growth and EPS production of Pseudoalteromonas sp. S - 15 - 13 were investigated, and the EPS was separated and purified for characterization analysis. The results showed that the optimal conditions for the EPS production were culture period, 56 h; growth temperature, 8 ℃ ; carbon source, 1.0% glucose; NaCI concentration, 3.0% ; pH 6.0 - 7.0. The EPS was purified by cold ethanol precipitation, proteins removal, ion exchange chromatography and gel chromatography technology. The molecular mass of EPS - H was 62 kDa as determined by the high performance gel permeation chromatography. Its sugar composition was a homopolymer of marmose analyzed by gas chromatograph spectroscopy. After repeated freezing and thawing of the bacteria hiomass in the presence of EPS, the bacterial growth was much higher than that observed after freezing in the absence of EPS and the difference augmented with the increase of freeze-thaw cycles. It is hypothesized that the adaptation of Pseudoalteromonas sp. S- 15 - 13 to the antarctic marine conditions, characterized by low temperature, high NaCl concentration and repeated freeze-thaw cycles, might be related to the EPS production ability.展开更多
AIM:To investigate the association between mutations in oligomerisation domain 2/caspase recruitment domains 15(NOD2/CARD15)and the natural history of Crohn’s disease(CD)to identify patients who would benefit from ea...AIM:To investigate the association between mutations in oligomerisation domain 2/caspase recruitment domains 15(NOD2/CARD15)and the natural history of Crohn’s disease(CD)to identify patients who would benefit from early aggressive medical intervention.METHODS:We recruited thirty consecutive unrelated CD patients with a history of ileo-caecal or small bowel resection during the period 1980-2000;Fifteen patients of these had post-operative relapse that required further surgery and fifteen did not.Full sequencing of the NOD2/CARD15 gene using dHPLC for exons 3,5,7,10 and 12 and direct sequencing for exons 2,4,6,8,9 and 11 was conducted.CD patients categorized as carrying variants were anyone with at least 1 variant of the NOD2/CARD15 gene.RESULTS:About 13.3%of the cohort(four patients)carried at least one mutant allele of 3020ins C of the NOD2/CARD15 gene.There were 20 males and 10females with a mean age of 43.3 years(range 25-69years).The mean follow up was 199.6 mo and a median of 189.5 mo.Sixteen sequence variations within the NOD2/CARD15 gene were identified,with 9 of them occurring with an allele frequency of greater than 10%.In this study,there was a trend to suggest that patients with the 3020ins C mutation have a higher frequency of operations compared to those without the mutation.Patients with the 3020insC mutation had a significantly shorter time between the diagnosis of CD and initial surgery.This study included Australian patients of ethnically heterogenous background unlike previous studies conducted in different countries.CONCLUSION:These findings suggest that patients carrying NOD2/CARD15 mutations follow a rapid and more aggressive form of Crohn’s disease showing a trend for multiple surgical interventions and significantly shorter time to early surgery.展开更多
文摘Twenty-seven antarctic bacteria producing extracellular polysaccharide （EPS） were selected from 57 strains by staining technology. The effects of major environmental factors on the growth and EPS production of Pseudoalteromonas sp. S - 15 - 13 were investigated, and the EPS was separated and purified for characterization analysis. The results showed that the optimal conditions for the EPS production were culture period, 56 h; growth temperature, 8 ℃ ; carbon source, 1.0% glucose; NaCI concentration, 3.0% ; pH 6.0 - 7.0. The EPS was purified by cold ethanol precipitation, proteins removal, ion exchange chromatography and gel chromatography technology. The molecular mass of EPS - H was 62 kDa as determined by the high performance gel permeation chromatography. Its sugar composition was a homopolymer of marmose analyzed by gas chromatograph spectroscopy. After repeated freezing and thawing of the bacteria hiomass in the presence of EPS, the bacterial growth was much higher than that observed after freezing in the absence of EPS and the difference augmented with the increase of freeze-thaw cycles. It is hypothesized that the adaptation of Pseudoalteromonas sp. S- 15 - 13 to the antarctic marine conditions, characterized by low temperature, high NaCl concentration and repeated freeze-thaw cycles, might be related to the EPS production ability.
文摘AIM:To investigate the association between mutations in oligomerisation domain 2/caspase recruitment domains 15(NOD2/CARD15)and the natural history of Crohn’s disease(CD)to identify patients who would benefit from early aggressive medical intervention.METHODS:We recruited thirty consecutive unrelated CD patients with a history of ileo-caecal or small bowel resection during the period 1980-2000;Fifteen patients of these had post-operative relapse that required further surgery and fifteen did not.Full sequencing of the NOD2/CARD15 gene using dHPLC for exons 3,5,7,10 and 12 and direct sequencing for exons 2,4,6,8,9 and 11 was conducted.CD patients categorized as carrying variants were anyone with at least 1 variant of the NOD2/CARD15 gene.RESULTS:About 13.3%of the cohort(four patients)carried at least one mutant allele of 3020ins C of the NOD2/CARD15 gene.There were 20 males and 10females with a mean age of 43.3 years(range 25-69years).The mean follow up was 199.6 mo and a median of 189.5 mo.Sixteen sequence variations within the NOD2/CARD15 gene were identified,with 9 of them occurring with an allele frequency of greater than 10%.In this study,there was a trend to suggest that patients with the 3020ins C mutation have a higher frequency of operations compared to those without the mutation.Patients with the 3020insC mutation had a significantly shorter time between the diagnosis of CD and initial surgery.This study included Australian patients of ethnically heterogenous background unlike previous studies conducted in different countries.CONCLUSION:These findings suggest that patients carrying NOD2/CARD15 mutations follow a rapid and more aggressive form of Crohn’s disease showing a trend for multiple surgical interventions and significantly shorter time to early surgery.
