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Z Cui

Publications and source records attributed to Z Cui.

At least 37 records · Page 2Linked to original sources
PubMed2001

[Studies on in vitro expression for gI gene of Marek's disease in E. coli by pGEX vector].

Glycoprotein I Gene(gI) was amplified from genomic DNA of Marek's disease virus (MDV) 648 strain by polymerase chain reaction(PCR). PCR product was cloned into pGEX-6p-1 according to the right open reading frame(ORF). The expression of GST-gI fusion protein was studied in detail on many factors including temperature, timing and IPTG. The curve for OD600 and the growing time of the recombinant bacteria is also established., which is helpful to find the optimal inducing time. GST-gI fusion protein was identified by SDS-PAGE and Western-blotting., and the result shows that the best concentration of IPTG is 0.2-0.5 mmol/L and inducing time have great effects on expression while temperature has little. The fusion protein was injected into mouse five times to identify its antigenicity and the result is positive in indirect fluorescent assay IFA.

Animals↗
PubMed2000

Cross-talk between transcriptional regulators of multidrug resistance in Saccharomyces cerevisiae.

Multiple or pleiotropic drug resistance often arises in the yeast Saccharomyces cerevisiae due to genetic alterations of the functional state of the Cys(6)-Zn(II)(2) transcription factors Pdr1p and Pdr3p. Single amino acid substitutions give rise to hyperactive forms of these regulatory proteins, which in turn cause overproduction of downstream target genes that directly mediate multidrug resistance. Previous work has identified a novel Cys(6)-Zn(II)(2) transcription factor designated Yrr1p as mutant forms of this protein confer high level resistance to the cell cycle inhibitor reveromycin A and DNA damaging agent 4-nitroquinoline-N-oxide. In the present study, we demonstrate that Yrr1p also mediates oligomycin resistance through activation of the ATP-binding cassette transporter-encoding gene YOR1. Additionally, insertion of triplicated copies of the hemagglutinin epitope in the C-terminal region of Yrr1p causes the protein to behave as a hyperactive regulator of transcription. We have found that YRR1 expression is both controlled in a Pdr1p/Pdr3p-dependent manner and autoregulated. Chromatin immunoprecipitation experiments also show that Yrr1p associates with target promoters in vivo. Together these data argue that the signal generated by activation of Pdr1p and/or Pdr3p can be amplified through the action of these transcriptional regulatory proteins on downstream target genes, like YRR1, that also encode transcription factors.

ATP-Binding Cassette Transporters↗
PubMed2000

Nuclear localization of enzymatically active green fluorescent protein-CTP:phosphocholine cytidylyltransferase alpha fusion protein is independent of cell cycle conditions and cell types.

To address the recent controversy about the subcellular localization of CTP:phosphocholine cytidylyltransferase alpha (CTalpha), this study was designed to visualize green fluorescent protein (GFP). CTalpha fusion proteins directly and continuously under different conditions of cell cycling and in various cell lines. The GFP. CTalpha fusion proteins were enzymatically active and capable of rescuing mutant cells with a temperature-sensitive CT. The expressed GFP.CTalpha fusion protein was localized to the nucleus in all cell lines and required the N-terminal nuclear targeting sequence. Serum depletion/replenishment did not cause shuttling of CTalpha between the nucleus and cytoplasm. Moreover, the subcellular localization of CTalpha was examined continuously through all stages of the cell cycle in synchronized cells. No shuttling of CTalpha between the nucleus and cytoplasm was observed at any stage of the cell cycle. Stimulation of cells with oleate had no effect on the localization of CTalpha. The GFP.CTalpha lacking the nuclear targeting sequence stayed exclusively in the cytoplasm. Regardless of their localization, the GFP.CTalpha fusion proteins were equally active for phosphatidylcholine synthesis and mutant rescue. We conclude that the nuclear localization of CTalpha is a biological event independent of cell cycle in most mammalian cells and is unrelated to activation of phosphatidylcholine synthesis.

Animals↗
PubMed2000

The assembly of very low density lipoproteins in rat hepatoma McA-RH7777 cells is inhibited by phospholipase A2 antagonists.

In McA-RH7777 cells, the oleate-stimulated assembly and secretion of very low density lipoproteins (VLDL) was associated with enhanced deacylation of phospholipids, which was markedly decreased by inactivation of the cellular phospholipase A(2). Treatment of the cells with antagonists or antisense oligonucleotide of the Ca(2+)-independent phospholipase A(2) (iPLA(2)) significantly inhibited secretion of apoB100-VLDL and triglyceride. Similar inhibitory effect of the iPLA(2) antagonists was observed on apoB48-VLDL secretion, but secretion of high density lipoprotein particles (such as apoAI- and apoB48-high density lipoprotein) or proteins in general was unaffected. The iPLA(2) antagonist did not affect the synthesis of apoB100 or triglyceride, nor did it affect the activities of phospholipase D, phosphatidate phosphohydrolase, or microsomal triglyceride transfer protein. Inactivation of iPLA(2) resulted in impaired apoB100-VLDL assembly as shown by decreased apoB100-VLDL and triglyceride within the microsomal lumen, with concomitant increase in apoB100 association with the microsomal membranes. The inhibitory effect of iPLA(2) antagonists on apoB100-VLDL assembly/secretion could be abated by pretreatment of cells with oleate. Analysis of molecular species of microsomal phosphatidylcholine and phosphatidylethanolamine by electron spray tandem mass spectrometry revealed that the enrichment of oleoyl moieties was altered by the treatment of iPLA(2) antagonist. These results suggest that the oleate-induced VLDL assembly/secretion may depend upon the establishment of membrane glycerolipids enriched in oleoyl chain, a process mediated by the iPLA(2) activity.

Animals↗
PubMed2000

Lysozyme separation by hollow-fibre ultrafiltration.

This paper discusses the purification of lysozyme from chicken egg white using hollow-fibre ultrafiltration (30kDa MWCO, polysulphone membrane). Lysozyme is preferentially transmitted through the membrane while the membrane largely retains other egg white proteins. Improvement in system hydrodynamics resulted in an increase in permeate flux while lysozyme transmission remained unaffected, leading to higher productivity. The percentage purity of lysozyme obtained was generally insensitive to system hydrodynamics. The permeate flux and productivity increased with increase in transmembrane pressure (TMP) before levelling off around 0.7bar. However, the TMP did not have any pronounced effect on the transmission and the purity of lysozyme. Experiments carried out in the diafiltration mode showed that moderately pure lysozyme (80-90%) could be obtained in an extended operation.

Journal Article↗
PubMed2000

Diphosphorylation of extracellular signal-regulated kinases and c-Jun N-terminal protein kinases in brain ischemic tolerance in rat.

Extracellular signal-regulated kinases (ERKs) and c-Jun N-terminal protein kinases (JNKs) activation in brain ischemic tolerance were examined by Western immunoblot. ERK but not JNK diphosphorylation (activation) were increased after preconditioning ischemia. The increased JNK1 but not ERK diphosphorylation after lethal ischemia was eliminated by pretreatment with preconditioning ischemia. The results suggest that the elimination of JNK1 activation after lethal ischemia by preconditioning ischemia may be one of the important protective mechanisms in ischemic tolerance, and ERKs activation may be involved in the induction of the protective responses.

Animals↗
PubMed2000

[Comparison of the expression and activity of phosphatidylethanolamine N-methyltransferase 2 between primary cultured hepatocytes and hepatoma cells in rats].

OBJECTIVE: To compare the expression and activity of phosphatidyl-ethanolamine N-methyltransferase 2 (PEMT(2)) between the primary cultured hepatocytes and CBRH7919 hepatoma cells in rats. METHODS: The expression and activity of PEMT(2) were demonstrated by immunochemistry, Western immunoblotting and [(3)H-CH(3)] SAM incorporation. Flow cytometry (FCM) was used to investigate the DNA content of the cells. RESULTS: PEMT(2) expression and activity were higher in the primary cultured hepatocytes than in hepatoma cells. Cell cycle analysis showed that the proportion of the hepatocytes was higher in G(1) phase and lower in S phase in the primary cultured hepatocytes than hepatoma cell lines. CONCLUSION: There is an intimate relationship between the expression of PEMT(2) and the proliferation of hepatocytes.

Animals↗
PubMed2000

[Pharmacodynamic effects of the extracts from Orobanche cumana].

Pharmacodynamic effects of the extracts from Orobanche cumana were studied for the first time. The result showed that it has the effects of antifatigue, facilitating immune function and an andrin-like action. It is consided that Orobanche cumana can be developed as a new medicinal resource plant.

Adjuvants, Immunologic↗
PubMed2000

[Expression of simian virus 40 large T-antigen and p53 protein in chinchilla middle ear epithelial cell line and its significance].

OBJECTIVE: To identify the expression of simian virus 40 large T-antigen (SV40TAg) and p53 protein in the cell nuclei of chinchilla middle ear epithelial cell line and explore the significance of the expression. METHODS: To examine the expression of SV40TAg and p53 protein in cell nuclei of chinchilla middle ear epithelial cell which had been infected and had not been infected with Ad 12-SV40 hybrid virus by immunocytochemistry method. RESULTS: All of the cell nuclei in 1 of 8 culturing dishes which infected with the Ad12-SV40 virus expressed the SV40TAg and p53 protein and had cultured over 46 passages. They have become a cell line. All of the cells in rest 7 culturing dishes and the control cells did not express the SV40TAg and p53 protein in their nuclei and died after culturing 6-8 passages. CONCLUSION: The SV40TAg and p53 protein play some important role in process of cell immortalization. The expression of SV40TAg and p53 protein in cell nuclei of CMEE-1 cell line has close interrelations with establishing the CMEE-1 cell line.

Animals↗
PubMed2000

[Rotational analysis of fluorescence excitation spectrum of NO2 in the range of 589.3-594.0 nm].

This paper shows the measurement of high-resolution fluorescence excitation spectrum of uncooled NO2 in the range of 589.3-594 nm. The 11 vibronic bands approximately 120 lines in this region were rotationally assigned. The analysis shows that these lines are mainly arise from the parallel transition of 2B2(K' = 0)-->2A2(K" = 0). The spectroscopic parameters describing these bands are obtained. The discussion is given to the complexity of spectrum structure.

Air Pollutants↗
PubMed1999

Molecular distinction of phosphatidylcholine synthesis between the CDP-choline pathway and phosphatidylethanolamine methylation pathway.

In addition to the CDP-choline pathway for phosphatidylcholine (PC) synthesis, the liver has a unique phosphatidylethanolamine (PE) methyltransferase activity for PC synthesis via three methylations of the ethanolamine moiety of PE. Previous studies indicate that the two pathways are functionally different and not interchangeable even though PC is the common product of both pathways. This study was designed to test the hypothesis that these two pathways produce different profiles of PC species. The PC species from these two pathways were labeled with specific stable isotope precursors, D9-choline and D4-ethanolamine, and analyzed by electrospray tandem mass spectrometry. Our studies revealed a profound distinction in PC profiles between the CDP-choline pathway and the PE methylation pathway. PC molecules produced from the CDP-choline pathway were mainly comprised of medium chain, saturated (e.g. 16:0/18:0) species. On the other hand, PC molecules from the PE methylation pathway were much more diverse and were comprised of significantly more long chain, polyunsaturated (e.g. 18:0/20:4) species. PC species from the methylation pathway contained a higher percentage of arachidonate and were more diverse than those from the CDP-choline pathway. This profound distinction of PC profiles may contribute to the different functions of these two pathways in the liver.

Animals↗
PubMed1999

[A report of recombinant interferon-alpha therapy in 19 patients with acute hepatitis B].

OBJECTIVE: In patients whose HBsAg are still positive after 8 weeks of acute hepatitis B attack, the chronic rate will increase. We try to treat them with IFN for reducing the rate of chronicity. METHODS: 19 patients were injected with rIFN-alpha 3 MU, q.o.d. for 12 weeks(treatment group), those who didn't have anti-HBs response after treatment were vaccinated with hepatitis B vaccine(30 micrograms, i.m., once weekly for 3 weeks); 15 patients received common therapy except rIFN-alpha(control group). RESULTS: HBsAg negative seroconversion rate was 95.0% (18/19) in treatment group and 53.0% (8/15) in control group(P < 0.05). No one responsed for anti-HBs in 18 HBsAg negatively converted patients in treatment group, but in control group 87.5% of HBsAg negatively converted patients developed anti-HBs (P < 0.001). Vaccinating the patients of treatment group, who didn't developed anti-HBs, with hepatitis B vaccine, 94.0% of them developed anti-HBs. After 24 to 240 week follow-up, no one relapsed in treatment group, in control group 8 HBsAg negative patients didn't replase, 6 out of 7 HBsAg positive patients were still positive at the termination and follow-up. CONCLUSION: The therapy with rIFN-alpha can reduce the chronic rate in the patients with acute HBV infection.

Acute Disease↗
PubMed1999

[Genetic linkage of polymorphisms of type I angiotensin II receptor gene to Chinese Han hypertension]

OBJECTIVE: To observe the CA repeat polymorphism of the type I angiotensin II receptor gene on Chinese Han people, and evaluate the genetic linking to hypertension. METHODS: The CA repeat polymorphism at 3'-flanking region of AT1R gene was studied by amplified fragment length polymorphism (Amp-FLP ) in Chinese Han people from Shandong and Xi'an. RESULTS: There were 9 alleles ranging from 130bp to 146bp in all subjects. The allele frequencies were 0.01 to 0.38, and allele A4 was more frequent in the control. The heterozygosity of CA repeat locus was 0.789, the polymorphic information content, 0.746. There was no significant difference in distribution of CA repeat polymorphism genotype between different regions in same ethnic (P>0.05), but the allele frequency of CA repeat polymorphism in hypertensive group was significantly different from that of control (P<0.05). There was no detectable distortion from Hardy-Weinberg equilibrium in both groups. CONCLUSION: The results suggest that CA repeat polymorphism of AT1R gene be associated with Chinese Han hypertensive people.

Journal Article↗
PubMed1999

Subcellullar localization, developmental expression and characterization of a liver triacylglycerol hydrolase.

The mechanism and enzymic activities responsible for the lipolysis of stored cytosolic triacylglycerol in liver and its re-esterification remain obscure. A candidate enzyme for lipolysis, a microsomal triacylglycerol hydrolase (TGH), was recently purified to homogeneity from pig liver and its kinetic properties were determined [Lehner and Verger (1997) Biochemistry 36, 1861-1868]. We have characterized the enzyme with regard to its species distribution, subcellular localization, developmental expression and reaction with lipase inhibitors. The hydrolase co-sediments with endoplasmic reticulum elements and is associated with isolated liver fat droplets. Immunocytochemical studies localize TGH exclusively to liver cells surrounding capillaries. Both TGH mRNA and protein are expressed in rats during weaning. The enzyme covalently binds tetrahydrolipstatin, an inhibitor of lipases and of triacylglycerol hydrolysis. The enzyme is absent from liver-derived cell lines (HepG2 and McArdle RH7777) known to be impaired in very-low-density lipoprotein (VLDL) assembly and secretion. The localization and developmental expression of TGH are consistent with a proposed role in triacylglycerol hydrolysis and with the proposal that some of the resynthesized triacylglycerol is utilized for VLDL secretion.

Animals↗
PubMed1999

Diminished expression of phosphatidylethanolamine N-methyltransferase 2 during hepatocarcinogenesis.

Phosphatidylethanolamine N-methyltransferase (PEMT) is a liver-specific enzyme that converts phosphatidylethanolamine into phosphatidylcholine. At least two forms of PEMT are present in hepatocytes. However, PEMT activity is negligible in two hepatoma cell lines. Previous studies have indicated an inverse relationship between the expression of one form, PEMT2, and the rate of liver growth, suggesting that this enzyme might be involved in inhibition of hepatocyte proliferation. We have now investigated the expression of PEMT2 at various stages of hepatocarcinogenesis induced by chemical carcinogens. Expression of PEMT2 protein was decreased in liver samples that contained the first detectable proliferative lesions. At later stages of carcinogenesis, PEMT2 expression was obliterated. PEMT activity decreased, the levels of PEMT2 mRNA decreased and there was an increase in the activity of CTP:phosphocholine cytidylyltransferase, a key regulatory enzyme in the CDP-choline pathway of phosphatidylcholine biosynthesis. Southern blot analyses of restriction fragments of DNA showed no changes in the PEMT gene in hepatocarcinoma compared with normal liver. A role for PEMT2 in the control of hepatocyte proliferation remains an intriguing possibility.

Animals↗
PubMed1999

Pharmacological properties of traditional medicines. XXV. Effects of ephedrine, amygdalin, glycyrrhizin, gypsum and their combinations on body temperature and body fluid.

Effects of ephedrine, amygdalin, glycyrrhizin, gypsum and their combinations on body temperature and body fluid were studied in rats using the method developed in our previous reports. Ephedrine significantly increased respiratory evaporative water loss and heat loss in response to a marked elevation of body temperature. There was a small but significant increase in body temperature when amygdalin was orally given rats at a dose of 46.32 mg/kg. Glycyrrhizin and gypsum were unable to affect body temperature. However, gypsum was able to prevent the increased action of ephedrine on body temperature, amygdalin exhibited a preventive tendency to it, and glycyrrhizin did not affect it. The results are in good agreement with classical claims of Makyo-kanseki-to and the related crude drugs in traditional medicine. Moreover, a combination of the four components reproduced the effects of Makyo-kanseki-to on body temperature and body fluid. This report suggests that the co-administration of ephedrine and gypsum is physiologically more desirable than ephedrine alone for dry-type asthmatic patients with a fever. Also, it experimentally supports the clinical efficacy of Makyo-kanseki-to.

Amygdalin↗