研究旨在探讨环二肽Cyclo(Leu-Pro)对植物乳杆菌生长的影响。该研究以植物乳杆菌(Lactobacillus Plantarum T1)为研究对象,采用高效液相色谱法初步定性定量植物乳杆菌T1发酵液中的Cyclo(Leu-Pro),然后将植物乳杆菌T1分别接种于不含或含...研究旨在探讨环二肽Cyclo(Leu-Pro)对植物乳杆菌生长的影响。该研究以植物乳杆菌(Lactobacillus Plantarum T1)为研究对象,采用高效液相色谱法初步定性定量植物乳杆菌T1发酵液中的Cyclo(Leu-Pro),然后将植物乳杆菌T1分别接种于不含或含不同质量浓度(0.5、1、5、10μg/mL)Cyclo(Leu-Pro)的MRS肉汤培养基中培养18 h,采用96孔法和平板计数法测定不同培养条件下植物乳杆菌T1的生长曲线和活菌数。结果表明:不同质量浓度的Cyclo(Leu-Pro)对植物乳杆菌T1的生长均有明显的促生长作用,其中,1μg/mL Cyclo(Leu-Pro)的促生长效果最佳,可将活菌数提高到8.73×10^(10) CFU/mL,相比于对照组提高了一个数量级。在不同胁迫条件下,1μg/mL Cyclo(Leu-Pro)能使植物乳杆菌T1的延滞期缩短、生长速度提高,其活菌数和生物量显著增加(P<0.05)。综上所述,Cyclo(Leu-Pro)促进了植物乳杆菌T1的生长,增强了其抗胁迫能力。这将有利于植物乳杆菌T1作为发酵剂在食品发酵领域的应用。展开更多
AIM: To investigate the influence of the CagA diversity in Helicobacter pylori (H. pylori ) strains from Colombia on the host cell biology. METHODS: Eighty-four H. pylori-cagA positive strains with different Glu-Pro-I...AIM: To investigate the influence of the CagA diversity in Helicobacter pylori (H. pylori ) strains from Colombia on the host cell biology. METHODS: Eighty-four H. pylori-cagA positive strains with different Glu-Pro-Ile-Tyr-Ala (EPIYA) motifs patterns, isolated from patients with gastritis (n=17), atrophic gastritis (n=17), duodenal ulcer (n=16), intestinal metaplasia (n=16) and gastric cancer (n=18), were included. To determine the integrity of the cag pathogenicity island (cag PAI) we evaluated the presence of cagA, cagT, cagE, and cag10 genes by polymerase chain reaction. AGS gastric epithelial cellswere infected with each strain and assayed for translo-cation and tyrosine phosphorylation of CagA by western blot, secretion of interleukin-8 (IL-8) by enzyme-linked immuno sorbent assay after taking supernatants from cocultures and cell elongation induction. For cell elongation quantification, coculture photographs were taken and the proportion of "hummingbird" cells (>15 μm) was determined. RESULTS: Overall 72% (60/84) of the strains were found to harbor a functional cag PAI. Levels of phos-phorylated CagA were significantly higher for isolates from duodenal ulcer than the ones in strains from gas-tritis, atrophic gastritis, intestinal metaplasia and gastric cancer (49.1% ± 23.1% vs 21.1% ± 19.5%, P < 0.02; 49.1% ± 23.1% vs 26.2%±14.8%, P<0.045; 49.1% ± 23.1% vs 21.5% ± 19.5%, P<0.043 and 49.1% ± 23.1% vs 29.5% ± 27.1%, P < 0.047 respectively). We observed variable IL-8 expression levels ranging from 0 to 810 pg/mL and from 8.8 to 1442 pg/mL at 6 h and 30 h post-infection, respectively. cagPAI-defective strains did not induce detectable levels of IL-8 at 6 h post-infection. At 30 h post-infection all strains induced IL-8 expression in AGS cells, although cagPAI-defective strains induced significantly lower levels of IL-8 than strains with a functional cagPAI (57.1 ± 56.6 pg/mL vs 513.6 ± 338.6 pg/mL,P < 0.0001). We did not observe differences in the extent of cell elongation induction between strains with a functional or a defective cagPAI in 6 h cocultures. At 24 h post infection strains with functionalcagPAI showed high diversity in the extent of hummingbird phenotype induction ranging from 7% to 34%. cag PAI defective strains induced significantly lower levels of elongation than strains with functional cag-PAI with one or more than one EPIYA-C motif (15.1% ± 5.2%vs 18.9% ± 4.7%,P < 0.03; and 15.1% ± 5.2% vs 20.0% ± 5.1%, P < 0.003 respectively). No differences were observed in cellular elongation inductionor IL-8 expression among H. pylori strains bearing one and more than one EPIYA-C motifs, neither at 6 h nor at 24 h of coculture. There were no associations between the levels of induction of cell elongation or IL-8 expression and number of EPIYA motifs or pathology. CONCLUSION: The present work describes a lack of association between H. pylori CagA protein EPIYA motifs variations from Colombian isolates and disease-associated cellular responses.展开更多
基金Supported by National Cancer Institute, Bogotá, Colombia,Grant No. 41030310 to Bravo MM and Sciences Faculty, LosAndes University, Bogotá, Colombia
文摘AIM: To investigate the influence of the CagA diversity in Helicobacter pylori (H. pylori ) strains from Colombia on the host cell biology. METHODS: Eighty-four H. pylori-cagA positive strains with different Glu-Pro-Ile-Tyr-Ala (EPIYA) motifs patterns, isolated from patients with gastritis (n=17), atrophic gastritis (n=17), duodenal ulcer (n=16), intestinal metaplasia (n=16) and gastric cancer (n=18), were included. To determine the integrity of the cag pathogenicity island (cag PAI) we evaluated the presence of cagA, cagT, cagE, and cag10 genes by polymerase chain reaction. AGS gastric epithelial cellswere infected with each strain and assayed for translo-cation and tyrosine phosphorylation of CagA by western blot, secretion of interleukin-8 (IL-8) by enzyme-linked immuno sorbent assay after taking supernatants from cocultures and cell elongation induction. For cell elongation quantification, coculture photographs were taken and the proportion of "hummingbird" cells (>15 μm) was determined. RESULTS: Overall 72% (60/84) of the strains were found to harbor a functional cag PAI. Levels of phos-phorylated CagA were significantly higher for isolates from duodenal ulcer than the ones in strains from gas-tritis, atrophic gastritis, intestinal metaplasia and gastric cancer (49.1% ± 23.1% vs 21.1% ± 19.5%, P < 0.02; 49.1% ± 23.1% vs 26.2%±14.8%, P<0.045; 49.1% ± 23.1% vs 21.5% ± 19.5%, P<0.043 and 49.1% ± 23.1% vs 29.5% ± 27.1%, P < 0.047 respectively). We observed variable IL-8 expression levels ranging from 0 to 810 pg/mL and from 8.8 to 1442 pg/mL at 6 h and 30 h post-infection, respectively. cagPAI-defective strains did not induce detectable levels of IL-8 at 6 h post-infection. At 30 h post-infection all strains induced IL-8 expression in AGS cells, although cagPAI-defective strains induced significantly lower levels of IL-8 than strains with a functional cagPAI (57.1 ± 56.6 pg/mL vs 513.6 ± 338.6 pg/mL,P < 0.0001). We did not observe differences in the extent of cell elongation induction between strains with a functional or a defective cagPAI in 6 h cocultures. At 24 h post infection strains with functionalcagPAI showed high diversity in the extent of hummingbird phenotype induction ranging from 7% to 34%. cag PAI defective strains induced significantly lower levels of elongation than strains with functional cag-PAI with one or more than one EPIYA-C motif (15.1% ± 5.2%vs 18.9% ± 4.7%,P < 0.03; and 15.1% ± 5.2% vs 20.0% ± 5.1%, P < 0.003 respectively). No differences were observed in cellular elongation inductionor IL-8 expression among H. pylori strains bearing one and more than one EPIYA-C motifs, neither at 6 h nor at 24 h of coculture. There were no associations between the levels of induction of cell elongation or IL-8 expression and number of EPIYA motifs or pathology. CONCLUSION: The present work describes a lack of association between H. pylori CagA protein EPIYA motifs variations from Colombian isolates and disease-associated cellular responses.
