关键词：
insulin;very low density lipoprotein receptor;cell proliferation;metabolic regulation
摘要：
This study examined the effect of insulin on the expression of very low density lipoprotein receptor (VLDLR) subtypes of SGC7901 cells and discussed its biological implication. In vitro, moderately or poorly-differentiated human gastric adenocarcinoma cell line SGC7901 was incubated with insulin for different lengths of time, and then the expression of protein and RNA level in VLDLR subtypes were detected by Western blotting and real-time PCR, respectively. The results showed that, at certain time interval, insulin could down-regulate expression of type I VLDLR and up-regulate the expression of type II VLDLR in SGC7901 cells, at both protein and RNA level. We are led to conclude that insulin serves as a regulator in maintaining the balance between glucose and lipid metabolism in vivo, possibly through its effect on the differential expression of VLDLR subtypes.
关键词：
ESCHERICHIA COLI;GENOTYPING;SHIGA LIKE TOXINS;ESCHERICHIA;FOOD SAFETY;GENETIC TECHNIQUES;TOXINS;VIRULENCE FACTORS
摘要：
Shiga toxin-producing Escherichia coli (STEC) can cause severe illnesses in humans such as hemorrhagic colitis and hemolytic-uremic syndrome. In this study, we carried out genotypic analysis of the Shiga toxin (stx) gene in 120 clinical isolates of STEC and enterohemorrhagic E. coli (EHEC) from patients in a southern district of Japan. We identified 88 stx(1)(+) and 103 stx(2)(+) strains. We further identified 12 stx(1)(+) and stx(2)(+) isolates expressing little or no Shiga toxin 1 (Stx(1)) and/or 2 (Stx(2)) by reversed passive latex agglutination (RPLA) and Vero cell toxicity assays. Among them, 1 strain could not produce Stx(1), 8 could not produce Stx(2), and 3 strains could produce neither. Two of the latter three strains were of the non-O157 serotype. Most of the Stx RPLA-negative strains belonged to the stx(1)/stx(2) subtype (11/12, [91.7%]). Our quantitative reverse transcription PCR analysis indicated that the stx genes were not effectively transcribed in the RPLA-negative strains. This is the first report of the isolation of stx-positive strains showing Stx-negative phenotype from stx(1)-bearing strains and non-O157 strains. (C) 2010 Elsevier Ltd. All rights reserved.
摘要：
In this study, an immediate aerobic-anaerobic-aerobic (O/A/O) biological process was established for the treatment of black liquor of cotton pulp and was tested by both laboratory-scale batch experiment and pilot-scale continuous experiment. The effects of the hydraulic retention time (HRT) were studied, as were the alkaliphilic bacteria number, the culturing temperature and the concentration of black liquor on COD (chemical oxygen demand) removal. The total COD (CODtot) removal rate of the novel O/A/O process, for a black liquor with influent CODtot over 8,000 mg/L and pH above 12.8, was 68.7 +/- 4% which is similar with that of the traditional acidic-anaerobic-aerobic process (64.9 +/- 3%). The first aerobic stage based on alkaliphilic bacteria was the crucial part of the process, which was responsible for decreasing the influent pH from above 12 to an acceptable level for the following treatment unit. The average generation time of the alkaliphilic bacteria in the black liquor was about 36 minutes at 40 degrees C in a batch aerobic activated sludge system. The efficiency of the first aerobic stage was affected greatly by the temperature. The CODtot removal at 55 degrees C was much lower in comparison with the CODtot removal at 45 degrees C or 50 degrees C. Both the laboratory-scale batch experiments and the pilot-scale continuous experiment showed that the CODtot removal rate could reach about 65% for original black liquor with a pH of about 13.0 and a COD of 18,000-22,000 mg/L by the immediate O/A/O process. The first aerobic stage gave an average CODtot removal of 45.5% at 35 degrees C (HRT 72 h) at a volume loading rate of 3.4 kg COD m(-3) d(-1).
摘要：
An alkaliphilic actinobacterium, designated strain CAAS 252(T), was isolated from the black liquor treatment system of a cotton pulp mill in Wuhan, China. Cells of strain CAAS 252(T) were Gram-positive, non-motile, non-endospore-forming, short rod-shaped, and grew optimally at 42 degrees C and pH 9-10 in the presence of 3 % (w/v) NaCl. Strain CAAS 252(T) contained MK-7, MK-8 and MK-9 as the major menaquinones and anteiso-C(17 : 0), anteiso-C(15 : 0) and C(16 : 0) as the predominant cellular fatty acids and had a peptidoglycan type of A4alpha, Lys-Gly-d-Asp. The DNA G+C content was 60.2 mol%. Based on analysis of 16S rRNA gene sequences (94.7-96.8 % similarity), DNA-DNA hybridization (<70 % relatedness) and chemotaxonomic characteristics, strain CAAS 252(T) belonged to the genus Nesterenkonia, but differed from all recognized species. Therefore, it is proposed that strain CAAS 252(T) represents a novel species of the genus Nesterenkonia, for which the name Nesterenkonia alba sp. nov. is proposed. The type strain is CAAS 252(T) (=CCTCC AB 207011(T)=DSM 19423(T)).
摘要：
Very low density lipoprotein receptor (VLDLR) is thought to participate in the pathogenesis of atherosclerosis induced by VLDL and beta-VLDL. The present study was undertaken to elucidate the effects of VLDL and beta-VLDL on VLDLR expression and its signaling pathway. RAW264.7 cells were incubated with VLDL and beta-VLDL. The expression of VLDLR mRNA was detected by RT-PCR. The transcriptional activity of VLDLR gene was detected in recombinant plasmid pGL4.2VR-luciferase transfected RAW264.7. Western blot assay was used to detect the changes of phosphorylated ERK1/2 protein. Inhibitors or activators were used to observe the signal pathway involving VLDLR expression regulation. The results showed that VLDL and beta-VLDL stimulated ERK1/2 activity in a PKC-dependent manner. VLDL or beta-VLDL-induced VLDLR expression on macrophages was extremely abolished by inhibitors ERK1/2 or PKC. Our findings revealed that VLDL or beta-VLDL-induced VLDLR expression via PKC/ERK cascades and the effect was linked to the transcriptional activation of VLDLR gene promoter.
摘要：
Archaea form a third domain of life that is distinct from Bacteria and Eukarya. According to the current knowledge, the basal transcription machinery of Archaea (including the core promoter architecture, the RNA polymerase, and the basal transcription factors) closely resembles that of Eukarya in structure and function, while differing considerably from the bacterial paradigm. In the present study, the promoter region of the halophilic archaeon Haloarcula hispanica's amyH gene was isolated and characterized, and it was surprisingly revealed that the amyH gene promoter could confer promoter activity (i.e., drive transcription) in haloarchaea (Archaea) as well as in Escherichia coli (Bacteria), where the transcriptions driven are initiated at the same adenine base. Further investigation revealed that the core structure of the amyH gene promoter possesses a combination of the typical structural characteristics of archaeal promoter, which are eukaryotic-like, and those of bacterial promoter. Our results indicate that the core promoter structures of some archaeal genes may possess a combination of eukaryotic- and bacterial-like features, and moreover, suggest a possible evolutionary relationship between basal transcription signals and transcription mechanisms of Archaea and the other two domains of life.
关键词：
Apoptosis;Cholesterol;Hepatocyte;Unfolded protein response
摘要：
Reported data indicate that cholesterol loading in the liver can cause hepatic injury. To explore the possible mechanisms of cell damage resulting from cholesterol overloading in hepatocytes, cell apoptosis, the unfolded protein response (UPR) and the correlation between them were assessed in the cholesterol-overloaded normal human hepatic cell line L02. L02 cells were incubated with 200 microg/ ml of low density lipoprotein (LDL) for 24 h with or without 20 microg/ml 58035, an inhibitor of acyl-CoA:cholesterol acyltransferase (ACAT). In the LDL+58035 group, the intracellular cholesterol level was dramatically increased, which was measured by an enzymatic combined high performance liquid chromatography assay. Expression of immunoglobulin-binding protein, X-box binding protein 1, activating transcription factor 6, activating transcription factor 4, CCAAT/enhancer-binding protein homologous protein-10, markers of endoplasmic reticulum stress (ERS)/ UPR, were up-regulated as determined using reverse transcription-polymerase chain reaction (RT-PCR) or Western blot analysis. The rate of cell apoptic death increased 21.3+/-2.4%. Meanwhile, the active caspase-3 protein expression was increased 8.4-fold compared to the active caspase-3 protein expression in the controls. Furthermore, 4-phenylbutyric acid, an inhibitor of UPR, partly reduced cell apoptosis and activation of caspase-3. This study suggests that cholesterol overloading in hepatic L02 cells induces ERS and activates the UPR which, in part, leads to the apoptotic damage of cells.
期刊：
International Journal of Food Microbiology,2008年121(2):195-200 ISSN：0168-1605
通讯作者：
Yuan, Zhiming
作者机构：
[Liu, Haizhou; Yuan, Zhiming; Zhou, Guoping; Yuan, Yongming] Chinese Acad Sci, State Key Lab Virol, Wuhan Inst Virol, Wuhan 430071, Peoples R China.;[Zhou, Guoping; He, Jing] Wuhan Polytech Univ, Dept Bioengn & Pharmaceut Engn, Wuhan 430023, Peoples R China.;[Liu, Haizhou; Zhou, Guoping; Yuan, Yongming] Chinese Acad Sci, Grad Sch, Beijing 100039, Peoples R China.
通讯机构：
[Yuan, Zhiming] C;Chinese Acad Sci, State Key Lab Virol, Wuhan Inst Virol, Wuhan 430071, Peoples R China.
关键词：
B. mycoides;B. thuringiensis;Bacillus cereus;Occurrence;Pasteurized full fat milk
摘要：
In 2006, a total of 54 samples of pasteurized full fat milk packaged in cartons were collected in spring and in autumn from chain supermarkets in Wuhan, China. The samples were examined and enumerated by MPN methods strictly according to guidelines laid out in US FDA/CFSAN BAM Chapter 14. Among 102 isolated B. cereus-like bacteria, 92 isolates were identified to be B. cereus, 9 B. thuringiensis and 1 B. mycoides. It was found that the occurrences of B. cereus were 71.4% and 33.3% in spring and in autumn samples respectively and the average count among the positive samples was 11.7 MPN/ml. The PCR detection results revealed that the enterotoxin genes hblA, hblC, hblD, nheA, nheB and nheC occurred in B. cereus isolates with frequencies of 37.0%, 66.3%, 71.7%, 71.7%, 62.0% and 71.7% respectively. Nine B. thuringiensis isolates were also identified from six pasteurized milk samples, and most of them harbored six enterotoxic genes and the insecticidal toxin cry1A gene. The single B. mycoides isolate harbored nheA and nheC genes. The data provides information for further evaluating the effect of B. cereus-like bacteria on food safety of Chinese milk products.
摘要：
In 2006, 54 pasteurized full fat milk samples, 40 ice-cream samples, and two green-tea beverage samples were analyzed and a total of 19 Bacillus thuringiensis-like strains were isolated, nine from seven pasteurized milks, one from an ice-cream with peach pulp and juice, and nine from two green-tea beverages. These strains were classified as B. thuringiensis, contained the cry1A gene and produced crystal inclusions during sporulation. All strains were characterized by a serotyping test, SDS-PAGE, random amplified polymorphic DNA, and enterotoxic gene PCR analysis. Most isolates produced bipyramidal crystals and belonged to serotypes H-3a3b, H-5a5b, or H-7. Furthermore. two strains from pasteurized full fat milks and three strains from green-tea beverages were indistinguishable from the B. thuringiensis subsp. kurstaki strains isolated from commercial biopesticides (Kaiyan (R), Qiangdi (R), Lvpuan (R) and Sutai (R)), suggesting the residual occurrences of B. thuringiensis from biopesticides in food and beverages. (C) 2008 Elsevier B.V. All rights reserved.
期刊：
INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY,2008年58(8):1927-1930 ISSN：1466-5026
通讯作者：
Yao, Bin
作者机构：
[Shi, Peng-Jun; Yao, Bin; Luo, Hui-Ying; Wang, Ya-Ru; Yang, Pei-Long] Chinese Acad Agr Sci, Feed Res Inst, Microbial Engn Dept, Beijing 100081, Peoples R China.;[Fan, Yun-Liu; Luo, Hui-Ying] Chinese Acad Agr Sci, Biotechnol Res Inst, Beijing 100081, Peoples R China.;[Miao, Li-Hong] Wuhan Polytechn Univ, Dept Biotechnol & Pharmaceut Engn, Wuhan 430023, Peoples R China.;[Fang, Chengxiang] Wuhan Univ, Coll Life Sci, Wuhan 430072, Peoples R China.
通讯机构：
[Yao, Bin] C;Chinese Acad Agr Sci, Feed Res Inst, Microbial Engn Dept, Beijing 100081, Peoples R China.
摘要：
A Gram-positive, non-motile, rod-shaped, non-spore-forming bacterium, designated CAAS 251(T), was isolated from paper-mill effluent in Wuhan, China. The organism grew optimally at 40-42 degrees C and at pH 9.0-10.0. The major menaquinones were MK-7, MK-8 and MK-9. The predominant cellular fatty acids were anteiso-C-15:0 (34.78 %), anteiso-C-17:0 (25.24%) and C-16:0 (13.37 %). The G + C content of the genomic DNA was 65.5 mol%. A phylogenetic analysis based on 16S rRNA gene sequences showed that strain CAAS 251(T) belongs to the genus Nesterenkonia, having sequence identities ranging from 96.0 to 97.0% with respect to eight recognized species of the genus Nesterenkonia. Data from DNA-DNA hybridization and physiological and biochemical tests indicated that strain CAAS 251(T) represents a novel species of the genus Nesterenkonia, for which the name Nesterenkonia flava sp. nov. is proposed. The type strain is CAAS 251(T) (=CCTCC AB 207010(T) =JCM 14814(T)).
摘要：
A new Iridoid glycosyl ester, scrophulninoside A (1), as well as the known compounds (2-3), were isolated from the n-BuOH soluble fraction of the Scrophularia ningpoensis. The structure of scrophulninoside A (1) was elucidated by spectroscopic methods.
作者机构：
[宗义强; 毕昊; 姚研怡; 过健俐; 屈伸] Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China;[刘志国] Department of Biotechnology and Chemical Engineering, Wuhan Polytechnic University, Wuhan, China
摘要：
In order to obtain three isoforms of apolipoprotein E (apoE), the cDNA encoding apoE3 was obtained by RT-PCR from normal human liver tissue. Site-directed mutagenesis was used to obtain the cDNAs encoding apoE2 and apoE4 isoforms. The 3 cDNAs were subcloned into vector pGEM-3Z and verified by DNA sequencing. The expression recombinant which can express the target protein as a (His) 6-tagged fusion was constructed by subcloning apoE cDNA into vector pT7-PL. The purified proteins were gained by Ni-NTA column. The SDS-PAGE results revealed the 6 His fusion proteins (apoE2, apoE3 and apoE4) were correctly expressed and purified successfully.
