从胆盐水解酶的特性出发,在干酪乳杆菌LC2W中过量表达Lactobacillus plantarum ST-III 4种胆盐水解酶同工酶,通过酶活性的测定研究胆盐水解酶对干酪乳杆菌水解胆盐的作用。结果表明:实现了4种胆盐水解酶在干酪乳杆菌LC2W的过表达;利用...从胆盐水解酶的特性出发,在干酪乳杆菌LC2W中过量表达Lactobacillus plantarum ST-III 4种胆盐水解酶同工酶,通过酶活性的测定研究胆盐水解酶对干酪乳杆菌水解胆盐的作用。结果表明:实现了4种胆盐水解酶在干酪乳杆菌LC2W的过表达;利用茚三酮显色法测定的4种重组菌胆盐水解酶活性较宿主LC2W都不同程度地降低;在干酪乳杆菌LC2W中过量表达L.plantarum ST-III的胆盐水解酶基因达不到提高该菌水解胆盐能力的目的。展开更多
采用低频脉冲磁场(low frequency pulsed magnetic field,LFPMF)对干酪乳杆菌LC2W进行照射,照射的最大强度为5 T.观察了磁场照射对乳杆菌菌体的生长和活力的影响,检测了磁场作用后菌体细胞膜的相关指标,包括菌体对超声波的抵抗性、细胞...采用低频脉冲磁场(low frequency pulsed magnetic field,LFPMF)对干酪乳杆菌LC2W进行照射,照射的最大强度为5 T.观察了磁场照射对乳杆菌菌体的生长和活力的影响,检测了磁场作用后菌体细胞膜的相关指标,包括菌体对超声波的抵抗性、细胞膜对羧基荧光素二乙酸盐琥珀酰亚胺酯(carboxyfluorescein diacetate succinimidyl ester,CFDA-SE)的通透性以及脂肪酸各组分的组成.实验结果表明:LFPMF对菌体的生长具有抑制作用,且经磁场照射后的菌体活力均有所降低;LFPMF作用后的菌体经超声波处理30 min后其存活率增加了37.9%,细胞膜通透性降低了20.3%,细胞膜的脂肪酸不饱和度由1.53提高至2.07,说明LFPMF对LC2W的细胞壁和细胞膜的组成和结构具有显著的影响.展开更多
This study investigated the intervention effects of Lactobacillus casei LC2W in murine(SPF C57BL/c)challenge infection models induced by Escherichia coli O157:H7.Mice were fed streptomycin with water for 3 days prior ...This study investigated the intervention effects of Lactobacillus casei LC2W in murine(SPF C57BL/c)challenge infection models induced by Escherichia coli O157:H7.Mice were fed streptomycin with water for 3 days prior to intragastric gavage by E.coli O157:H7(Control)or L.casei LC2W together with E.coli O157:H7(Intervention)to explore the role of L.casei LC2W by biochemical indicators,histological evaluation,expression of colonic pro-inflammatory and intestinal barrier factors related to enteritis.Results showed that the administration of L.casei LC2W was able to alleviate the symptoms of colitis induced by E.coli O157:H7,exhibiting lower weight loss as well as more intact colon tissue.Furthermore,L.casei LC2W could down-regulate the expression of pro-inflammatory cytokines(TNF-α,IL-6,and IL-1β)and protect the intestinal barrier function by improving the level of MUC2,ZO-1 and E-cadherin 1 compared to the control group.These results demonstrate that L.casei LC2W can reduce the severity of E.coli O157:H7 infection,and suggest L.casei LC2W may maintain the immune balance and intestinal barrier to reduce colitis.In addition,we found the effect of intervention is similar to that of prevention,which is better than that of treatment.展开更多
Proper flowering time is essential for plant reproduction. Winter annual Arabidopsis thaliana needs ver-nalization before flowering, during which AtVILs （VIN3 and VRNS, components of PRC2 complex） mediate the H3K27 ...Proper flowering time is essential for plant reproduction. Winter annual Arabidopsis thaliana needs ver-nalization before flowering, during which AtVILs （VIN3 and VRNS, components of PRC2 complex） mediate the H3K27 tri- methylation at the FLC locus （a floral repressor） to repress the FLC expression and hence to induce flowering. However, how VILs （VIL, VERNALIZATION INSENSITIVE 3-LIKE） function in rice is unknown. Here we demonstrated that rice LC2 （OsVIL3） and OsVIL2 （two OsVILs, possible components of PRC2 complex） promote rice flowering. Our results showed that expressions of LC2 and OsVIL2 are induced by SD （short-day） conditions and both Ic2 mutant and OsVIL2-RNAi lines display delayed heading date, consistent with the reduced expression levels of Hdl and Hd3a. Interestingly, LC2 binds to the promoter region of a floral repressor OsLF and represses the OsLF expression via H3K27 tri-methylation modification. In addition, OsLF directly regulates the Hdl expression through binding to Hdl promoter. These results first demonstrated that the putative PRC2 in rice is involved in photoperiod flowering regulation, which is different from that of Arabidopsis, and revealed that LC2 binds the promoter region of target gene, presenting a possible mechanism of the recruitment pro-cess of PRC2 complex to its target genes. The studies provide informative clues on the epigenetic control of rice flowering.展开更多
文摘从胆盐水解酶的特性出发,在干酪乳杆菌LC2W中过量表达Lactobacillus plantarum ST-III 4种胆盐水解酶同工酶,通过酶活性的测定研究胆盐水解酶对干酪乳杆菌水解胆盐的作用。结果表明:实现了4种胆盐水解酶在干酪乳杆菌LC2W的过表达;利用茚三酮显色法测定的4种重组菌胆盐水解酶活性较宿主LC2W都不同程度地降低;在干酪乳杆菌LC2W中过量表达L.plantarum ST-III的胆盐水解酶基因达不到提高该菌水解胆盐能力的目的。
文摘采用低频脉冲磁场(low frequency pulsed magnetic field,LFPMF)对干酪乳杆菌LC2W进行照射,照射的最大强度为5 T.观察了磁场照射对乳杆菌菌体的生长和活力的影响,检测了磁场作用后菌体细胞膜的相关指标,包括菌体对超声波的抵抗性、细胞膜对羧基荧光素二乙酸盐琥珀酰亚胺酯(carboxyfluorescein diacetate succinimidyl ester,CFDA-SE)的通透性以及脂肪酸各组分的组成.实验结果表明:LFPMF对菌体的生长具有抑制作用,且经磁场照射后的菌体活力均有所降低;LFPMF作用后的菌体经超声波处理30 min后其存活率增加了37.9%,细胞膜通透性降低了20.3%,细胞膜的脂肪酸不饱和度由1.53提高至2.07,说明LFPMF对LC2W的细胞壁和细胞膜的组成和结构具有显著的影响.
基金supported by the National Key Research and Development Program of China(No.2018YFD0501600)National Natural Science Foundation of China(No.31972056)Shanghai Agriculture Applied Technology Development Program,China(Grant No.2019-02-08-00-07-F01152).
文摘This study investigated the intervention effects of Lactobacillus casei LC2W in murine(SPF C57BL/c)challenge infection models induced by Escherichia coli O157:H7.Mice were fed streptomycin with water for 3 days prior to intragastric gavage by E.coli O157:H7(Control)or L.casei LC2W together with E.coli O157:H7(Intervention)to explore the role of L.casei LC2W by biochemical indicators,histological evaluation,expression of colonic pro-inflammatory and intestinal barrier factors related to enteritis.Results showed that the administration of L.casei LC2W was able to alleviate the symptoms of colitis induced by E.coli O157:H7,exhibiting lower weight loss as well as more intact colon tissue.Furthermore,L.casei LC2W could down-regulate the expression of pro-inflammatory cytokines(TNF-α,IL-6,and IL-1β)and protect the intestinal barrier function by improving the level of MUC2,ZO-1 and E-cadherin 1 compared to the control group.These results demonstrate that L.casei LC2W can reduce the severity of E.coli O157:H7 infection,and suggest L.casei LC2W may maintain the immune balance and intestinal barrier to reduce colitis.In addition,we found the effect of intervention is similar to that of prevention,which is better than that of treatment.
文摘Proper flowering time is essential for plant reproduction. Winter annual Arabidopsis thaliana needs ver-nalization before flowering, during which AtVILs （VIN3 and VRNS, components of PRC2 complex） mediate the H3K27 tri- methylation at the FLC locus （a floral repressor） to repress the FLC expression and hence to induce flowering. However, how VILs （VIL, VERNALIZATION INSENSITIVE 3-LIKE） function in rice is unknown. Here we demonstrated that rice LC2 （OsVIL3） and OsVIL2 （two OsVILs, possible components of PRC2 complex） promote rice flowering. Our results showed that expressions of LC2 and OsVIL2 are induced by SD （short-day） conditions and both Ic2 mutant and OsVIL2-RNAi lines display delayed heading date, consistent with the reduced expression levels of Hdl and Hd3a. Interestingly, LC2 binds to the promoter region of a floral repressor OsLF and represses the OsLF expression via H3K27 tri-methylation modification. In addition, OsLF directly regulates the Hdl expression through binding to Hdl promoter. These results first demonstrated that the putative PRC2 in rice is involved in photoperiod flowering regulation, which is different from that of Arabidopsis, and revealed that LC2 binds the promoter region of target gene, presenting a possible mechanism of the recruitment pro-cess of PRC2 complex to its target genes. The studies provide informative clues on the epigenetic control of rice flowering.
