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Biomedical subjects

B Qian

Publications and source records attributed to B Qian.

33 records · Page 2Linked to original sources
PubMed1997

Detection of enterotropic mouse hepatitis virus fecal excretion by polymerase chain reaction.

A reverse transcription and polymerase chain reaction method was developed and used to detect fecal excretion of enterotropic mouse hepatitis virus (MHV). A nested set of primers for polymerase chain reaction was located in the polymerase region of the MHV genome. The assay was used to follow the time course of enterotropic MHV excretion in mice after oronasal inoculation with the virus. The assay detected MHV genome excretion in all mice beginning on day 3 through day 21 after inoculation. No MHV genome was detected in inoculated mice on or after day 27 following inoculation. This time course of detection of excreted virus corresponded to the period of infectivity of this isolate in a previous study. These results indicate that reverse transcription and polymerase chain reaction are useful for enterotropic MHV detection in specimens that are easily and noninvasively obtained and are clinically relevant.

Animals↗
PubMed1996

Determination of the 5' and 3' terminal noncoding sequences of the bi-segmented genome of the avibirnavirus infectious bursal disease virus.

Terminal sequences of the bi-segmented dsRNA genome of 3 different strains of infectious bursal disease virus (IBDV) were analyzed by the rapid amplification of cDNA 5' ends (5'RACE) procedure. Both segments are 85% homologous in a 32-nucleotide sequence comprising the 5' end, whereas the 3' end has a conserved pentamer. Comparison to published terminal sequences of other IBDV strains revealed high conservation between the two segments but more serotype-specific nucleotide changes (5 on segment A and 3 on segment B) in the 5' noncoding region compared to the 3' noncoding region (none on segment A and 1 on segment B).

Animals↗
PubMed1996

Restriction fragment profiles of genome segment A of infectious bursal disease virus correlate with serotype and geographical origin of avibirnaviruses.

Previous analysis of the two serotypes of infectious bursal disease virus (IBDV) have demonstrated the correlation between antigenicity and similarities of nucleotide and amino acid sequences of the VP2 coding region in genome segment A. Restriction fragment profiles of genomic segment A cDNA of five IBDV isolates (QC-2 and QT-1 of serotype 1, SK9, and Nos. 39 and 52 of serotype 2) were determined in order to establish the genetic relationship of these viruses to other avibirnaviruses. The restriction fragment profiles using three of seven restriction enzymes (SacI which cuts in the VP2 region, DraIII which cuts in the VP3 region, and EcoRI which cuts in the VP4 region) were used to place QC-2, QT-1, SK9, No. 39, and No. 52 within the phylogenetic tree among seven other avibirnaviruses of known sequence. The two IBDV serotypes corresponded to two genotypes on the basis of the presence or absence of the SacI restriction site. The serotype 1 cluster of strains was further differentiated into five minor clusters on the basis of the PstI, EcoRI, BamHI, HindIII, DraIII, and Bsu361 restriction sites, which emphasized the geographical origins of the strains. It is concluded that restriction analysis of cDNA of the whole viral genomic segment A allows differentiation of IBDV isolates on the basis of their antigenicity and geographical origin.

Australia↗
PubMed1995

Development of a specific biotinylated DNA probe for the detection of Renibacterium salmoninarum.

A specific DNA probe for the identification of Renibacterium salmoninarum, the causative agent of bacterial kidney disease (BKD), was developed from one of 3 clones pRS47, pRS49, and pRS26 of 5.1 kb, 5.3 kb, and 11.3 kb, respectively. The biotinylated pRS47/BamHI insert probe was tested on 3 dilutions of DNA extracted from 3 strains of R. salmoninarum and from 1 strain each of Arthrobacter protophormiae, Aeromonas salmonicida, Corynebacterium aquaticum, Carnobacterium piscicola, Listonella anguillarum, Micrococcus luteus, Pseudomonas fluorescens, Vibrio ordalii, and Yersinia ruckeri. In a dot blot assay, this probe hybridized only with the DNA from the R. salmoninarum strains. When used on kidney samples from fish challenged with R. salmoninarum, the dot blot hybridization assay with the probe was found to be as sensitive as culture. In a fluorescent antibody test, samples that were negative in culture and dot blot hybridization showed no more than one fluorescing cell in 50 microscopic fields examined. This DNA probe, therefore, has the potential for use in the diagnosis of BKD of fish.

Actinomycetales↗
PubMed1994

Sequence conservation in the RNA polymerase gene of infectious bursal disease viruses.

Eleven of thirteen infectious bursal disease viruses (IBDV) were shown to be similar following polymerase chain reaction (PCR) amplification of two regions (293 bp and 651 bp cDNA fragments) in genomic segment B and restriction enzyme analysis of the PCR products. Two IBDV strains differed from the eleven viruses when examined by BstEII digestion of the 293 bp PCR product, but all thirteen viruses were similar using the 651 bp cDNA fragment and digestion with AvaI. Because segment B encodes replicating enzyme(s), the results suggest that its sequences may be highly conserved among IBDV isolates.

Animals↗
PubMed1994

Observations on polymerase chain reaction amplification of infectious bursal disease virus dsRNA.

Two methods for denaturing double stranded (ds)RNA of infectious bursal disease virus for the purpose of reverse transcribing it were compared: Heat denaturation at 65 degrees C in the presence of DMSO and in the absence of DMSO. As part of the analysis, the nature of cDNA in the two preparations was examined by polymerase chain reaction (PCR) amplification, firstly by varying the number of cycles of PCR, and secondly by re-amplification of serial dilutions of the reaction products. The results show that denaturation of dsRNA in the presence of DMSO (method 1) is superior to denaturation without DMSO (method 2) judging by the yield of a specific PCR fragment after 30 cycles, and that the products of method 2 can be re-amplified, albeit poorly, with the generation of heterologous products.

Base Sequence↗
PubMed1990

[Effects of bee pollen on lipid peroxides and immune response in aging and malnourished mice].

The results showed that the level of hemolysin (HC), the numbers of plaque forming cells (PFC) and specific rosette forming cells (SRFC) in primary response to sheep red blood cells (SRBC) were markedly lowered and the lipoperoxide level in brain, liver and serum was increased in aging (over 18 months) and malnourished mice fed with ground corn in comparison to normal controls, while HC and the numbers of PFC and SRFC were significantly increased and the lipoperoxide level was markedly decreased after treatment with bee pollen 10 g/kg/d orally for 3 months and with 20% bee pollen-containing ground corn for 3 weeks respectively. The reduction of total protein and albumin contents of serum, DNA, RNA and protein contents of spleen and thymus in mice fed with ground corn can be prevented by adding 20% bee pollen in ground corn diet.

Aging↗
PubMed1989

Characterization of a variant rat glutathione S-transferase by cDNA expression in Escherichia coli.

We have isolated a glutathione S-transferase Yb1 subunit cDNA from a lambda gt11 cDNA collection constructed from rat testis poly(A) RNA enriched for glutathione S-transferase mRNA activities. This Yb1 cDNA, designated pGTR201, is identical to our liver Yb1 cDNA clone pGTR200 except for a shorter 5'-untranslated sequence. Active glutathione S-transferase is expressed from this Yb1 cDNA driven by the tac promoter on the plasmid construct pGTR201-KK. The expressed glutathione S-transferase protein begins with the third codon (Met) of the cDNA, and is missing the N-terminal proline of rat liver glutathione S-transferase 3-3. Therefore, our Escherichia coli expressed glutathione S-transferase protein represents a variant form of glutathione S-transferase 3-3 (Yb1Yb1), designated GST 3-3(-1). The expressed Yb1 subunits are assembled into a dimer as purified from sonicated E. coli crude extracts. In the absence of dithiothreitol three active isomers can be resolved by ion-exchange chromatography. The pure protein has an extinction coefficient of 9.21 x 10(4) M-1 cm-1 at 280 nm or E0.1% 280 = 1.78 and a pI at 8.65. It has a substrate specificity pattern similar to that of the authentic glutathione S-transferase 3-3. The GST 3-3(-1) has a KM of 202 microM for reduced GSH and of 36 microM for 1-chloro-2,4-dinitrobenzene. The turnover number for this conjugation reaction is 57 s-1. Results of kinetic studies of this reaction with GST 3-3(-1) are consistent with a sequential substrate binding mechanism. We conclude that the first amino acid proline of glutathione S-transferase 3-3 is not essential for enzyme activities.

Animals↗
PubMed1988

Gene expression of rat glutathione S-transferases. Evidence for gene conversion in the evolution of the Yb multigene family.

We have characterized a cDNA with complete coding sequence for the rat liver glutathione S-transferase subunit 4 (Yb2) isolated from a constructed lambda gt10 cDNA library. Functional expression of the cDNA sequence has resulted in the purification to homogeneity of an enzymatically active anionic glutathione S-transferase. In addition to three previously described Yb-type subunits (Yb1, Yb2, Yb3), we now report characterization of a fourth Yb subunit sequence in the form of a genomic DNA clone lambda GTR15-2. The Yb4 gene has no apparent defect, and the deduced Yb4 polypeptide sequence differs from the other three Ybs by 40 to 53 amino acids. The Yb4 gene organization is similar to that of the Yb2 gene in having a minimum of eight exons. Three out of the seven introns between the two genes are conserved to the extent of more than 88% nucleotide identity. We propose that gene conversion may have played a role in the evolution of these Yb genes.

Amino Acid Sequence↗
PubMed1986

Human liver glutathione S-transferases: complete primary sequence of an Ha subunit cDNA.

Multiple human liver GSH S-transferases (GST) with overlapping substrate specificities may be essential to their multiple roles in xenobiotics metabolism, drug biotransformation, and protection against peroxidative damage. Human liver GSTs are composed of at least two classes of subunits, Ha (Mr = 26,000) and Hb (Mr = 27,500). Immunological cross-reactivity and nucleic acid hybridization studies revealed a close relationship between the human Ha subunit and rat Ya, Yc subunits and their cDNAs. We have determined the nucleotide sequence of the Ha subunit 1 cDNA, pGTH1. The alignments of its coding sequence with the rat Ya and Yc cDNAs indicate that they are approximately 80% identical base-for-base without any deletion or insertion. Regions of sequence homology (greater than 50%) have also been found between pGTH1 and a corn GST cDNA and rat GST cDNAs of the Yb and Yp subunits. Among the 62 highly conserved amino acid residues of the rat GST supergene family, 56 of them are preserved in the Ha subunit 1 coding sequences. Comparison of amino-acid replacement mutations in these coding sequences revealed that the percentage divergence between the rat Ya and Yc genes is more than that between the Ha and Ya or Ha and Yc genes.

Amino Acid Sequence↗
PubMedDate not supplied

Primary malignant melanoma arising from the base of the tongue.

A rare case of malignant melanoma of the base of the tongue in a 65-year-old Japanese woman is described. The primary and metastatic tumors were treated by surgery, chemohormone and immunotherapy. There was no recurrence for 5 years after the initial diagnosis. Electron microscopy suggested that the melanosomes of the melanoma cells in the cervical lymph nodes were less mature than those in the primary melanoma cells; melanosome immaturity was consistent with a more aggressive quality.

Aged↗