Proteomics analysis of Listeria monocytogenes ATCC 19115 in response to simultaneous triple stresses.

Listeria monocytogenes can cause listeriosis in humans through consumption of contaminated food. L. monocytogenes can adapt and grow in a vast array of physiochemical stresses in the food production environment. In this study, we performed a proteomics strategy in order to investigate how L. monocytogenes survives with a simultaneous exposure to low pH, high salinity and low temperature. The results showed that the adaptation processes mainly affected the biochemical pathways related to protein synthesis, oxidative stress, cell wall and nucleotide metabolism. Interestingly, enzymes involved in the carbohydrate metabolism of energy, such as glycolysis and pentose phosphate pathway, were derepressed due to the down-regulation of CodY, a global transcriptional repressor. The down-regulation of CodY, together with the up-regulation of carbohydrate metabolism enzymes, likely leads to the accumulation of pyruvate and further to the activation of fatty acid synthesis pathway. Proteomics profiling offered a better understanding of the physiological responses of this pathogen to adapt to harsh environment and would hopefully contribute to improving the food-processing and storage methods.

Effect of N0R1 gene on expression of E-selectin in HepG 2 cells / 肿瘤

Objective: To study the effect of NOR1 gene on expression of E-selectin in HepG2 cells. Methods: NOR1 gene was transfected into human liver cancer HepG2 cells mediated by cationic lipofectamine. The total RNA was extracted. The mRNA expressions of NORI gene and E-selectin in HepG2 cells were detected by reverse transcription polymerase chain reaction (RT-PCR). The level of E-selectin protein in the supernatant of cell culture was determined by ELJSA method. Results:The results of RT-PCR showed that the mRNA expression of E-selectin in NOR1 gene transfection group was significantly higher than those in blank group and control group (P<0.01). The results of ELISA showed that the protein level of E-selectin in the supernatant of cell culture was significantly higher in NOR1 gene transfection group than those in the blank group and control group (P<0.01). Conclusion: NOR1 gene could induce the increase in E-selectin expression in HepG2 cells.

[Postoperative detection of AFP mRNA in the peripheral blood of hepatic cellular carcinoma patients and its correlation with recurrence].

OBJECTIVE: The postoperative presence of alpha-fetoprotien (AFP) mRNA in the peripheral blood of patient with hepatic cellular carcinoma (HCC) may suggest that carcinomatous cells still exist in the peripheral blood which may someday develop into metastasis. Therefore, the expression of AFP mRNA in postoperative peripheral blood is detected and its correlation with recurrence of HCC is investingated. METHODS: AFP mRNA in peripheral blood of HCC patients and non-hepatic cellular carcinoma patients treated by partial hepatectomy on the first, 7th, 14th postoperative day was examined by means of RT-PCR/ Southern blot. All HCC patients were followed up for 36 months. RESULTS: Of the 29 HCC patients, 18 (62.1%) had recurrence, and 17 (58.6%) was found to have AFP mRNA expression in peripheral blood during postoperative period. Fourteen of these 17 patients (82.4%) with positive AFP mRNA expression developed recurrence, but only 4 patients (33.3%) with negative AFP mRNA expression had recurrence. The difference between two groups was statistically significant (P < 0.05). CONCLUSION: Our preliminary results suggest that detection of AFP mRNA during postoperative period may be helpful in predicting recurrence for hepatic cellular carcinoma.

[Effects of meisoindigo on the expression of globin gene in vitro].

OBJECTIVE: The pathophysiology of beta-thalassemia is the imbalance of the alpha and non-alpha globin chain which leads to a series of clinical symptoms of hemolytic anemia. Scientists continuously try to explore gene-activated drugs to increase the level of non-alpha globin chain or decrease the level of alpha globin chain in the treatment of beta-thalassemia. To probe into the effects on globin-gene expression of meisoindigo (Me) in cultured erythroid cells derived from peripheral blood, so as to provide the theoretical basis for applying Me in the treatment of beta-thalassemia. METHODS: By using the two-step liquid culture of erythroid progenitor cells and reverse transcription polymerase chain reaction (RT-PCR), and by using alpha mRNA as an inner control, the level of gamma mRNA and beta mRNA in cultured erythroid cells derived from peripheral blood of 11 patients with severe beta-thalassemia and 6 normal volunteers were measured under the effect of different concentration (2.5 micro mol/L, 5 micro mol/L and 10 micro mol/L) of Me. RESULTS: (1) No statistic significance was found in the ratio of beta/alpha mRNA by Me in cultured cells from both normal individuals and beta-thalassemia. (2) Me can significantly increase the ratio of gamma/alpha mRNA and (beta + gamma)/alpha mRNA (that is non-alpha/alpha mRNA) in cultured cells from normal individuals and beta-thalassemia. The ratio of gamma/alpha mRNA was increased 0.31 - 0.45 times and the ratio of non-alpha mRNA/alpha mRNA increased 0.21 - 0.32 times in Me induced cells from normal individuals. No significant result was observed among the different concentrations of Me (2.5 micro mol/L, 5 micro mol/L and 10 micro mol/L) in normal individuals. With the increasing of Me concentrations, the ratios of gamma/alpha mRNA and alpha/alpha mRNA were increased in cultured cells from beta-thalassemia. The ratio of gamma/alpha mRNA was increased 0.33 - 1.17 times and the ratio of non-alpha/alpha mRNA increased 0.25 - 0.89 times in Me induced cells from beta-thalassemia. There was no significant difference between the concentrations of 2.5 micro mol/L and 5 micro mol/L concentration in beta-thalassemia. However, there was significant difference between the concentrations of 10 micro mol/L and the concentrations of 2.5 micro mol/L and 5 micro mol/L in beta-thalassemia. (3) The increase of the ratio of gamma/alpha mRNA and non-alpha/alpha mRNA in beta-thalassemia was higher than that in normal individual with induction by Me with a higher concentration (10 micro mol/L). CONCLUSION: Me can raise the ratio of gamma/alpha mRNA and non-alpha/alpha mRNA in cultured erythroid cells derived from peripheral blood of both normal individual and beta-thalassemia in the level of transcription, which can improve the imbalance of the alpha and non-alpha globin chain. So Me has a latent value in the therapy of beta-thalassemia.

[Analysis on HLA-E polymorphism in Guangdong Han population].

To investigate the distribution of HLA-E alleles and linkage between HLA-E and HLA-A or -B loci in Chinese Han in Guangdong area, HLA-E alleles were detected by using PCR-SSP in 150 unrelated healthy individuals from Guangzhou area; HLA-A, -B antigens typing in 106 individuals was carried out with NIH standard microlymphocytoxic method. Analysis of linkage was performed between HLA-E and HLA-A, -B. The results showed that three alleles of HLA-E could be detected in this population. They are E * 0101, E * 01031, E * 01032, with the frequency of 45.33%, 32.33%, 22.33% respectively. No E * 0102 and E * 0104 could be detected in all of these individuals. The analysis of linkage on two loci between HLA-E and HLA-A or -B showed that no significant difference could be found between expected frequencies and observed frequencies except B15/E * 01032 and A2/E * 01032. In conclusion, the high conservative polymorphism of HLA-E suggests that it's biological characteristic is different from that of classical HLA class Ia molecules.

[Effect of transfection of hEndostatin gene on CNE2 cell xenograft growth in nude mice].

BACKGROUND & OBJECTIVE: Tumor angiogenesis play an important role in growth and metastasis of cancer. Angiogenesis inhibitors induce apoptosis in cancer by inhibiting tumor angiogenesis and have strong inhibiting effect on both growth and metastasis of cancer. This study was designed to explore the effect of transfection of human endostatin gene on nasopharyngeal carcinoma CNE2 cells xenograft growth in nude mice. METHODS: The plasmids (pBlast-hIL-hEndostatin, pBlast-hEndostatin, and pBlast-MCS) were transfected and lipofectin-mediated into the CNE2 cell line. The biological activity of secreted hEndostain from gene-transferred cell lines was determined using MTT method in vitro. Then the transfected CNE2 cells were injected into the nude mice and tumorigenicity of CNE2 was observed in vivo. RESULTS: The supernatant of CNE2 cell transfected with pBlast-hIL-hEndostatin effectively inhibited the growth of endothelial cell (ECV304). The volume and the weight of tumor in pBlast-hIL -hEndostatin transfecting cells group were less than those in control group (P< 0.01). The growth speed of tumor in pBlast-hIL-hEndostatin transfecting cells group was slower than that in control group. CONCLUSION: Transfection of hEndostatin gene could inhibit CNE2 cell growth in nude mice.

The relationship of lmp2 and DR3 genes with susceptibility to type I diabetes mellitus in south China Han population.

AIM:To study the relationship of lmp2 and DR3 genes with type I diabetes mellitus.METHODS:lmp2 genotypes and DR3 were identified in 68 patients with type I diabetes mellitus (I -DM) and 71 healthy controls. Then,I -DM patients and controls were respectively allocated into DR3-positive and DR3-negative groups. The frequencies of lmp2 and DR3 gene in random subjects, and lmp2 genotypes in DR3 matched subjects were compared between I -DM patients and controls. At the same time, I DM patients were divided into 3 groups based on the onset age of diabetics:group A < = 14 years, group B 15-30 years and group C > = 31 years.RESULTS:The frequency of DR3 in I-DM patients was significantly higher than that in controls (47% vs 21%, P < 0.005), and it was significantly higher in group A than that in group B+C (70% vs 36%, X(2) = 7.07, P < 0.01). There was a significant difference among groups with different onset age of diabetics (X(2) = 8.19, rp = 0.33, P <0.05). In random subjects, the frequency of lmp2-R/R in I -DM patients was lower (43% vs 61%, P <0.05)and lmp2-R/H higher (53% vs 28%, P<0.05) than that in controls, and there was no significant difference among groups with different onset age of diabetics.In DR3-positive subjects, the frequency of lmp2-R/R in I-DM patients was lower (47% vs 87%, P<0.05) and lmp2-R/H higher (47% vs 13%, P <0.05) than that in controls. In DR3-negative subjects,the frequency of lmp2-R/H in I -DM patients was higher than that in controls (58% vs 32%, P <0.01), but the frequency of lmp2-R/R and lmp2-H/H was not significantly different between these two groups.CONCLUSION:DR3 gene may be one of the susceptible genes of I-DM,and significantly related to the onset age of diabetics, and the persons with DR3 may have an younger onset age of diabetes.The lmp2-R/R may be the protective genotype of I-DM, and lmp2-R/H the susceptible genotype. These were not affected by DR3 gene. lmp2 genotypes were not related with the onset age of diabetics.