Biomedical subjects

Qin Wang

Publications and source records attributed to Qin Wang.

132 records · Page 8Linked to original sources

PubMed2000

Cloning and Identification of Genes Related with Morphogenesis of Candida albicans.

A Candida albicans cDNA library was constructed and screened by differential hybridization. In hybridization using probes derived from population of yeast cells or hyphae, 67 recombinant phages exhibited more intense signal with the probe derived from hyphae than with the probe from yeast cells. One phage behaved vice versa. Physical map analysis and nucleotide sequence analysis suggested that cDNA of the CX1, a clone specific for yeast form, coded for cytochrome P450 L1A1 (Lanosterol 14alpha-demethylase). Its specific expression pattern was confirmed by Northern analysis. Inhibition of serum on the expression of CX1 cDNA was observed. CX2 cDNA was one of those giving intensive signal with hyphae probes. The cDNA sequence contained a tandem repeat sequence, which was also found in ALS1, another Candida albicans gene identified, whose expression was related with morphogenesis. Northern analysis proved that it was expressed intensively with hyphae probes, however the expression could not be detected in those strongly hybridized to yeast cell probes. The locations of both cDNA on chromosome were analyzed.

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PubMed1999

Molecular Cloning of MAPK Gene Family Using Synthetic Oligonucleotide Probe.

MAPK(mitogen activated protein kinase) is a kind of Ser/Thr protein kinase. The MAPKs play an important role in several different signal transduction pathways. The MAPKs may also have a role in morphorgenesis of Candida albicans. An oligonucleotide probe was used to screen novel MAPKs in C. albicans. All MAPKs shared high homogeneity in their eleven kinase subdomains, especially subdoman VII and VIII. In subdomain VII, nearly all MAPKs have the same KIDFGLAR sequence, and the two known MAPKs in C. albicans CEK1 and MKC1 have only one different nucleotide in that DNA sequence. This probe was hybridized with C. albicans genomic DNA. Under stringent conditions, the probe could only hybridize with CEK1 and MKC1 gene fragment. But when hybridized at 40 degrees in non-SDS solution, two novel bands appeared. This condition was used to screen SC5314 DNA library, and many positive clones with different hybridization density were obtained. The strongest hybridization clones were identified to contain CEK1 and MKC1 gene. From the stronger positive hybridization clones, two novel genes were identified. The first gene, named CRK1(CDC2-related protein kinase 1), shared high homogeneity to MAPKs, but was not of them. It is closest to SGV1 from S. cerevisiae (with homology 47%) and PITALRE from human (with homology 41%), both of which are CDC2-related protein kinases. The second gene called CEK2(Candida albicans extracelluar signal-regulated kinase 2) is a novel MAPK of Candida albicans, which shares the highest identity with CEK1 and its S. cerevisiae homologs, FUS3 and KSS1, two redundant MAPKs in yeast pheromone response and morphogenesis.

Journal Article↗

PubMed1999

Functions of CRK1 Gene of Candida albicans as Studied by Gene Knock-out.

In the course of screening MAPK related protein kinase genes from Candida albicans DNA library, a CRK1 (CDC2-related protein kinase) gene was identified. Deletion of the CRK1 gene significantly decreased the growth. rate of cells. CRK1 knock out strains precipitated more rapidly in YPD liquid medium. The CRK1 null mutant stimulated hyphae formation in Lee's liquid medium at pH 4.5 and 25 degrees, which is the medium that maintains the wild type Candida albicans strain in yeast form. These phenomena suggest that CRK1 gene may be involved in cell cycle, flocculation and morphogenesis of Candida albicans. Overexpression of the half length CRK1 gene could induce the invasive growth into agar faintly, the cells that was capable of the invasive growth also changed their cell shapes to long, thin pseudohyphal-like cells, but the full-length CRK1 had only weak effect. The Crk1p might promote the invasive growth or cell elongation through a route different from the MAPK signal transduction pathway.

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PubMed1996

Preparation of Neoglycoproteins by Using Homo-bifunctional Reagent as the Coupling Agent.

Several neoglycoproteins (Man-BSA, Gal-BSA, Glc-BSA, Lac-BSA, GlcNAc-BSA, Fuc-BSA and Rha-BSA) have been prepared by using homo-bifunctional reagents (divinyl sulfone, DVS and 1,4-butanediol diglycidyl ether, Epoxy) as coupling agents and purilied with the respective immobilized lectins (except Fuc-BSA and Rha-BSA). These purified neoglycoproteins showed binding specificity to the corresponding lectins by hemagglutinating inhibition test and double diffusion experiment.

Journal Article↗

PubMedDate not supplied

Zein adsorption to hydrophilic and hydrophobic surfaces investigated by surface plasmon resonance.

Zein, the prolamine of corn, has been investigated for its potential as an industrial biopolymer. In previous research, zein was plasticized with oleic acid and formed into sheets/films. Physical properties of films were affected by film structure and controlled in turn by zein-oleic acid interactions. The nature of such interactions is not well understood. Thus, protein-fatty acid interactions were investigated in this work by the use of surface plasmon resonance (SPR). Zein adsorption from 75% aqueous 2-propanol solutions, 0.05% to 0.5% w/v, onto hydrophilic and hydrophobic self-assembled monolayers (SAMs) formed by 11-mercaptoundecanoic acid and 1-octanethiol, respectively, was monitored by high time resolution SPR. Initial adsorption rate and ultimate surface coverage increased with bulk protein concentration for both surfaces. The initial slope of plotted adsorption isotherms was higher on 11-mercaptoundecanoic acid than on 1-octanethiol, indicating higher zein affinity for hydrophilic SAMs. Also, maximum adsorption values were higher for zein on hydrophilic than on hydrophobic SAMs. Flushing off loosely bound zein in the SPR cell allowed estimation of apparent monolayer values. Differences in monolayer values for hydrophobic and hydrophilic surfaces were explained in terms of zein adsorption footprint.

Adsorption↗

PubMedDate not supplied

Colorectal cancer screening attitudes and practices in the general population: a risk-adjusted survey.

OBJECTIVES: To characterize self-reported colorectal cancer (CRC) screening behavior, and to identify characteristics of CRC screening practices, stratified by risk. METHODS: Using random-digit-dial methodology, we conducted telephone surveys in US adults 50 years of age and older. Respondents provided data on utilization of CRC screening tests; demographic characteristics; and awareness, concerns, attitudes and beliefs about the tests, CRC, and health care. On the basis of available guidelines, three definitions of adequate screening were considered. RESULTS: Among persons reporting having ever had a CRC screening exam, the exam was more likely to have been a fecal occult blood test than a radiologic or endoscopic exam (p < .0001). Subjects at increased CRC risk were more likely to have met the screening criteria (p < .001) compared with average-risk subjects. Receipt of information or advice about cancer screening tests, male gender, and concern about managed care were positively associated with adequate screening. Smoking, low health self-monitoring, and an average risk for CRC reduced the probability of CRC screening. CONCLUSIONS: Lack of awareness about screening remains common, regardless of CRC risk. Providing information and advice about cancer screening may be the single most important tool available to improve screening rates.

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