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Biomedical subjects

Z N Wang

Publications and source records attributed to Z N Wang.

16 recordsLinked to original sources
PubMed2001

Liver receptor homologue-1 is expressed in the adrenal and can regulate transcription of 11 beta-hydroxylase.

Liver receptor homologue-1 (LRH-1, designated NR5A2) is a mammalian homologue of Drosophila fushi tarazu factor (dFTZ-F1) and structurally belongs to the orphan nuclear receptor superfamily. LRH-1 can recognize the DNA sequence 5'-AAGGTCA-3', the canonical recognition motif for steroidogenic factor 1 (SF-1). Herein, we hypothesized that LRH-1 might play a role in the regulation of human adrenal expression of steroidogenic enzymes. To test this hypothesis, LRH-1 expression in human adult and fetal adrenal glands was examined by RT-PCR analysis. The fetal and adult adrenal glands, as well as liver and pancreas, were observed to express LRH-1 mRNA using RT-PCR. The ability of LRH-1 to enhance transcription of the gene encoding human 11 beta- hydroxylase (hCYP11B1) was then examined using the H295R adrenal cell line. LRH-1 co-transfection with hCYP11B1 luciferase promoter constructs caused a 25-fold induction of luciferase activity. Furthermore, co-transfection of a hCYP11B1 reporter construct containing a mutation in the SF-1 binding cis-element abolished the stimulatory effect of both SF-1 and LRH-1. Electrophoretic mobility shift assay (EMSA) demonstrated that LRH-1 could bind to the SF-1 response element. Taken together, our data suggested that LRH-1 is expressed in the adrenal, and can substitute for SF-1 to enhance transcription of genes encoding certain of the steroid-metabolizing enzymes. A role for LRH-1 in the regulation of adrenal or gonadal steroid hormone production should be further studied.

Adrenal Glands↗
PubMed2001

Gene profiling of human fetal and adult adrenals.

The mechanisms that lead to the steroidogenic differences in the human fetal adrenal (HFA) and adult adrenal gland are not known. However, gene expression clearly plays a critical role in defining their distinct steroidogenic and structural phenotypes. We used DNA microarrays to compare expression levels of several thousand transcripts between the HFA and adult adrenal gland. Total RNA was isolated from 18 HFA and 12 adult adrenal glands. Samples of total RNA were used to make five pools of poly A+ RNA (mRNA). Gene profiling was done using five independent microarrays that contained between 7075 and 9182 cDNA elements. Sixty-nine transcripts were found to have a greater than 2.5-fold difference in expression between HFA and adult adrenals. The largest differences were observed for transcripts that encode IGF-II (25-fold higher in HFA) and 3beta-hydroxysteroid dehydrogenase (24-fold higher in adult). Among the other genes, transcripts related to sterol biosynthesis or to growth and development were higher in the HFA than adult adrenals. Transcripts concerned with cellular immunity and signal transduction were preferentially expressed in the adult adrenal. The vast majority of the 69 transcripts have not been studied with regard to adrenal function. Thus, these gene profiles provide valuable information that could help define the mechanisms that control adrenal function.

3-Hydroxysteroid Dehydrogenases↗
PubMed2000

Visualization of A- and B-genome chromosomes in wheat (Triticum aestivum L.) x jointed goatgrass (Aegilops cylindrica Host) backcross progenies.

Wheat (Triticum aestivum) and jointed goatgrass (Aegilops cylindrica) can cross with each other, and their self-fertile backcross progenies frequently have extra chromosomes and chromosome segments, presumably retained from wheat, raising the possibility that a herbicide resistance gene might transfer from wheat to jointed goatgrass. Genomic in situ hybridization (GISH) was used to clarify the origin of these extra chromosomes. By using T. durum DNA (AABB genome) as a probe and jointed goatgrass DNA (CCDD genome) as blocking DNA, one, two, and three A- or B-genome chromosomes were identified in three BC2S2 individuals where 2n = 29, 30, and 31 chromosomes, respectively. A translocation between wheat and jointed goatgrass chromosomes was also detected in an individual with 30 chromosomes. In pollen mother cells with meiotic configuration of 14 II + 2 I, the two univalents were identified as being retained from the A or B genome of wheat. By using Ae. markgrafii DNA (CC genome) as a probe and wheat DNA (AABBDD genome) as blocking DNA. 14 C-genome chromosomes were visualized in all BC2S2 individuals. The GISH procedure provides a powerful tool to detect the A or B-genome chromatin in a jointed goatgrass background, making it possible to assess the risk of transfer of herbicide resistance genes located on the A or B genome of wheat to jointed goatgrass.

Chromosome Mapping↗
PubMed2000

[Alpha-acetolactate decarboxylase from B. licheniformis AS10106: cloning and expression gene in E. coli and S. cerevisiae].

A genomic library of B. licheniformis AS10106 that contained the alpha-acetolactate decarboxylase gene(alpha-ALDC) was constructed with vector pUC19 and host E. coli JM109 strain. The inserted fragments of foreign DNA ranged from 4 to 10 kb in the 4800 clones thus obtained. Six positive clones were detected after screening the plated library by the method of clony coloration. Subcloning of the DNA fragment containing the alpha-acetolactate decarboxylase gene showed that the alpha-acetolactate decarboxylase gene was on an 1.6 kb BamH I-EcoR I fragment. Preliminary analysis of the enzyme expressed from one recombinant plasmid pGEA showed that the properties of the recombinant enzyme, such as the optimal temperature and pH of reaction, were identical to those of the native enzyme. Using yeast-E. coli shuttle vector pYES2, an expression recombinant plasmid pYEA containing B. licheniformis AS10106 alpha-acetolactate decarboxylase gene was constructed. S. cerevisiae H158 transformed with pYEA had expressed alpha-acetolactate decarboxylase activity and shown the ability to reduce the formation of diacetyl during beer fermentation.

Carboxy-Lyases↗
PubMed2000

[Tissue culture induced translocation conferring powdery mildew resistance between wheat and Dasypyrum villosum and its marker-assisted selection].

Glutamate oxaloacetate transaminase (GOT) electrophoretic analyses were performed in 175 regenerants arising from immature embryos of crosses between wheat (Triticum aestivum L.) and 6D/6V substitution stocks. The GOT-V2 coding specific enzyme band was absent in two regenerants, designated 98R149 and 98R159 respectively, originated from cross of Yi 4095 and 6D/6V substitution stock c.v. RW15. Pm21 gene linked SCARs (Sequence Characterized Amplified Regions) analysis indicated that 6VS chromosome arms existed in 98R149 and 98R159. Fluorescence in situ hybridization with total genomic DNA extracted from Dasypyrum villosum (L.) as a probe confirmed the occurrence of translocation between 6V chromosome and a wheat one in the two regenerants mentioned above. 98R149 and 98R159 were immune to powdery mildew (Erysiphe graminisDC. f. sp. tritici) inoculation with mix races collected from Hebei Province. The results of the present paper added another feasible example of useful translocations via tissue culture.

Aspartate Aminotransferases↗
PubMed2000

Effects of salvianolic acid-A on rat hepatic stellate cell proliferation and collagen production in culture.

AIM: To investigate the effects of salvionolic acid-A (SA-A), one of main effective components of Salvia miltiorrhiza for its antifibrotic action, on the cell proliferation and collagen production in cultured hepatic stellate cells (HSC). METHODS: HSC were isolated through in situ perfusion of liver with pronase E and collagenase, and gradient centrifugation with Nycodenz. The cultured HSC were incubated with SA-A 0.1-100 mumol/L for 24 h. MTT spectrometric assay and intercellular incorporation of methyl-[3H]thymidine ([3H]TdR) was used to assess the cell proliferation. The amount of collagen was semi-quantified by ponceau staining and image analysis, the amount of type I collagen secretion was measured with ELISA and normalized by the total protein of cell layer. The total RNA was prepared from the control cells and the drug treated cells respectively, and the expression of pro-collagen alpha 2 (I) mRNA was semi-quantitatively analyzed with RT-PCR. RESULTS: SA-A 100 mumol/L showed a little cytotoxity, SA-A 0.1-10 mumol/L did not influence cell morphology, and SA-A 1-100 mumol/L decreased the cell proliferation significantly in a concentration-dependent manner (P < 0.05). SA-A 1, 10, 100 mumol/L decreased the cell collagen deposition by 78.6%, 71.8%, and 61.3% of the control respectively (P < 0.05), and decreased type I collagen secretion to 53.1%, 52.6%, and 49.5% (P < 0.01 or P < 0.05). Both SA-A 1 and 10 mumol/L downregulated procollagen alpha 2 (I) mRNA expression remarkably (P < 0.05). CONCLUSION: SA-A inhibited HSC proliferation and collagen expression. The inhibitory effect on HSC activation is the main mechanism of SA-A action against liver fibrosis.

Animals↗
PubMed2000

[Immunologic histochemical observation of anti-crypt keratin of cryptic epithelium of tonsilla in children with chronic tonsillitis].

OBJECTIVE: To investigate anti-crypt keratin (CK) immunologic histochemical changes in children with chronic tonsillitis. METHOD: Removed tonsilla were fixed by 10% formaldehyde. Immunologic histochemical method was used to determine the changes of anti-broad spectrum (KD 68, 56, 56, 50) CKSP. RESULT: In 230 cases, obvious keratosis was 90.9%, no keratosis was 9.1%, 3 cases were found with fungus filaments and bacteria in the bottom of crypts. Anti-broad spectrum and hypermolecule CK of tonsil cryptic epithelium were positive reaction, anti-broad spectrum CK of cryptic keratosis in all cases was positive reaction. CONCLUSION: During the period of episode, cryptic epitheliums of tonsilla was destroyed repeatly, therefore, immunoglobulin production was reduce. Because the immune function of tonsilla was reduced, bacteria and virus might be invade into organism. This reduplicative malignant circles must be interrupted or blocked only by tonsillectomy.

Adolescent↗
PubMed1998

Expression of the extracellular domain of the human immunodeficiency virus type 1 envelope protein and its fusion with beta-galactosidase in Saccharomyces cerevisiae.

Two envelope glycoprotein gene fragments were cloned from the proviral genome of the HXB2 isolate of human immunodeficiency virus (HIV). For the production of the two domains of the envelope gene product these cloned gene fragments were inserted into an Escherichia coli-yeast inducible shuttle vector fused to the galactokinase (GAL1) promoter. Cell extracts from strains of Saccharomyces cerevisiae harboring these two vectors (pYENV1 and pYENV2) were found to contain a specific protein with a size of 50 kDa when induced by galactose, while the protein could not be detected in extracts from control cells containing only the E. coli-yeast vector in the presence of galactose. Furthermore, another expression plasmid coding for fusion proteins from the majority of the external envelope glycoprotein (gp120) moiety and a large part of the beta-galactosidase was constructed. Antibodies from HIV type 1-positive sera could react with recombinant fusion polypeptides. Transformants could produce this fusion protein to a level of about 1.6% of the total protein content, as deduced from beta-galactosidase activity.

Cloning, Molecular↗
PubMed1995

Cytochrome P450(11 beta): structure-function relationship of the enzyme and its involvement in blood pressure regulation.

Cytochrome P450(11 beta) is deeply involved in the final steps of biosynthesis of mineralocorticoids. This paper deals with following issues about this enzyme. (1) The structure and function of the enzymes of various animal species are discussed. By making alignment of amino acid sequences of the enzymes, we identified peptide domains essential for the enzyme actions such as a putative steroid binding domain and a heme binding region. Estimates of molecular similarity among the P450(11 beta) family enzymes suggested that the enzymes having both 11 beta-hydroxylation activity and aldosterone (ALDO) synthetic activity of certain animals such as frog, cattle and pig are more similar to the ALDO synthases of the other animals, such as rat, mouse and human, than the 11 beta-hydroxylases of these animals. (2) The molecular nature of the P450(11 beta) family enzymes of genetically hypertensive rats as well as adrenal regeneration hypertension (ARH) rats is examined. (i) Mutation was found in the P450(11 beta) gene of Dahl's salt-resistant normotensive rat. Steroidogenic activity expressed by the mutated gene accounted well for abnormal plasma levels of steroid hormones in this rat. (ii) 11 beta-, 18- and 19-Hydroxylation activities of adrenal mitochondrial prepared from spontaneously hypertensive rat (SHR), Wistar-Kyoto rat (WKY), and stroke-prone (SP)-SHR were not significantly different from each other. Levels of mRNA of ALDO synthase in adrenal glands of 50-week-old SHR was significantly lower than those of 10-week-old SHR, WKY and SHR-SP. (iii) No significant difference in 19-hydroxylation activity was found between adrenal mitochondria prepared from ARH rat and those from control rat. The level of message of ALDO synthase was lower in adrenal glands of ARH rat.

Aldosterone↗
PubMed1992

Transfer of IncP Plasmids to Extremely Acidophilic Thiobacillus thiooxidans.

The broad-host-range IncP plasmids RP4, R68.45, RP1::Tn501, and and pUB307 were transferred directly to extremely acidophilic Thiobacillus thiooxidans from Escherichia coli by conjugation at frequencies of 10 to 10 per recipient. The ability of T. thiooxidans to receive and express the antibiotic resistance markers was examined. The plasmid RP4 was transferred back to E. coli from T. thiooxidans at a frequency of 1.0 x 10 per recipient.

Journal Article↗