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Biomedical subjects

Z Y Zhu

Publications and source records attributed to Z Y Zhu.

At least 19 recordsLinked to original sources
PubMed2003

Characterization of cDNA encoding immunoglobulin light chain of the mandarin fish (Siniperca chuatsi).

Immunoglobulin light chain cDNA sequences of a perciform fish, the mandarin fish Siniperca chuatsi were amplified from head kidney mRNA by reverse transcription (RT)-PCR and RACE methods using degenerated primer and gene specific ones. In cDNA sequences of the VL region, nucleotide exchanges were present mainly within CDRs, although a lesser degree of variability was also found in FRs. Moreover, the length of CDR1 and CDR3 in the mandarin fish is shorter than in most other fish species. In the middle of S. chuatsi CL region, a microsatellite sequence (AGC)(6-8) was found, which is also present in another perciform species, the spotted wolffish (Anarhichas minor). The comparison of amino acid sequence of the mandarin fish CL domain with those of other vertebrates showed the highest degree of similarity of 94.5% to the spotted wolffish, while the similarity with rainbow trout (Oncorhynchus mykiss) Ig L1 (62.7%) and channel catfish (Ictalurus punctatus) Ig LG (55.9%) isotypes is also higher. However, there is only 50% identity in the VL regions between the mandarin fish and the wolffish. The sequence similarity of the mandarin fish CL domain with those of higher vertebrate did not readily allow it to be classified as kappa or lambda isotype. The phylogenetic analyses also demonstrated that the CL genes of the mandarin fish and most other teleost fish cluster as a separate branch out of the mammal kappa and lambda branches.

Amino Acid Sequence↗
PubMed2002

The integration of four major determinants of antibiotic action: bactericidal activity, postantibiotic effect, susceptibility, and pharmacokinetics.

A functional pharmacokinetic/pharmacodynamic (PK/PD) index that could simultaneously describe three controlling PD variables, i.e., bactericidal activity, postantibiotic effect (PAE), and susceptibility, in relation to pharmacokinetics, was designed using an in vitro kinetic model. Tobramycin was tested against one standard and five clinical strains of Pseudomonas aeruginosa. The organisms showed minimum inhibitory concentrations (MICs) ranging between 1 and >1000 microg/ml. The model allowed antibiotic concentrations to be reduced exponentially from initial concentrations at fixed multiples of MIC. Antibiotic removal was performed when the decreasing concentrations hit the MIC of individual strain to provide a wide range of AUC(>MIC) within an identical frame of AUC(>MIC)/MIC (AUIC) values. Viable counts were measured at antibiotic addition and before/after its removal for bactericidal activity and PAE assessments. A linear relationship was observed between PAE and bactericidal rate constants, though the pattern varied among different strains. Characterization of the exposure (AUC(>MIC))-effect relationships using the Emax model revealed that the less susceptible strains displayed lower Emax and higher EC50 for both antimicrobial effects. By employing the AUIC as a common frame of reference, regression analysis showed a significant linear correlation (p < 0.05) between the mean PAE and bactericidal rate data and, thereby simultaneously defining the four contributing factors of the PK/PD system. It appears that the AUIC, by conveying the pharmacokinetic and susceptibility information, could serve as a PK/PD index in bridging the interdependency of PAE and bactericidal activity. More importantly, the collective assessment of these four factors would allow more optimal evaluation of dosage regimens.

Anti-Bacterial Agents↗
PubMed2001

Complete nucleotide sequence of the S10 genome segment of grass carp reovirus (GCRV).

Hemorrhagic disease, caused by the grass carp reovirus (GCRV), is one of the major diseases of grass carp in China. Little is known about the structure and function of the gene segments of this reovirus. The S10 genome segment of GCRV was cloned and the complete nucleotide sequence is reported here. The S10 is 909 nucleotides long and contains a large open reading frame (ORF) encoding a protein of 276 amino acids with a deduced molecular weight of approximately 29.7 kDa. Comparisons of the deduced amino acid sequence of GCRV S10 with those of other reoviruses revealed no significant homologies. However, GCRV S10 shared a putative zinc-finger sequence and a similar distribution of hydrophilic motifs with the outer capsid proteins encoded by Coho salmon aquareovirus (SCSV) S10, striped bass reovirus (SBRV) S10, and mammalian reovirus (MRV) S4. It was predicted that this segment gene encodes an outer capsid protein.

Amino Acid Sequence↗
PubMed2001

Molecular characterization and expression of the M6 gene of grass carp hemorrhage virus (GCHV), an aquareovirus.

The complete nucleotide sequence of M6 gene of grass carp hemorrhage virus (GCHV) was determined. It is 2039 nucleotides in length and contains a single large open reading frame that could encode a protein of 648 amino acids with predicted molecular mass of 68.7 kDa. Amino acid sequence comparison revealed that the protein encoded by GCHV M6 is closely related to the protein mu1 of mammalian reovirus. The M6 gene, encoding the major outer-capsid protein, was expressed using the pET fusion protein vector in Escherichia coli and detected by Western blotting using chicken anti-GCHV immunoglobulin (IgY). The result indicates that the protein encoded by M6 may share a putative Asn-42-Pro-43 proteolytic cleavage site with mu1.

Amino Acid Sequence↗
PubMed2001

[Prokaryotic expression of recombinant grass carp growth hormone].

The recombinant plasmid containing a synthetic grass carp growth hormone cDNA was transformed into Escherichia coli BL21 (DE3) and expressed efficiently, induced by 1 mmol/L IPTG. 12.5% SDS-PAGE showed the molecular weight of new added protein in Escherichia coli BL21 (DE3) is consistent with that of grass carp growth hormone. The recombinant protein was composed of approximately 40% of the total bacterial proteins. The target protein was purified with Ni-NTA affinity column. Western-blotting conformed that recombinant protein could specifically react with antibody against grass carp growth hormone. ELISA-receptor assay showed the bioactivity of recombinant protein is consistent with that of nature grass carp growth hormone.

Animals↗
PubMed2001

[Comparative study on antibody levels of vaccination group and control group after 4 years of immunized with type B inactivated vaccine against hemorrhagic fever with renal syndrome].

OBJECTIVE: To compare the antibody level of vaccine group and control group in a randomized, controlled trial of type B inactivated vaccine against hemorrhagic fever with renal syndrome(HFRS) in Jiande County of Zhejiang Province and to find out if there is enhancement of subclinical infection about type B inactivated vaccine against HFRS. METHODS: The number of sera collected (July 1994-July 1998) in vaccine group immunized type B inactivated vaccine against HFRS and control group were 305 and 283 persons in Jiande County respectively, and indirect immunofluorescent antibody method(IFAT) was used for testing the titer of HFRS IgG in sera. The cut-off values were determined on IFA titer of the second sera in control group with positive and negative IFA before vaccine was given respectively, and the subclinical infection of positive and negative IFA of the first sera in vaccine group was evaluated. RESULTS: When taking different cut-off values of subclinical infection, there were no statistical differences in HFRS IFA positive rates between vaccine group and control group of positive IFA in the first sera. In vaccine group and control group of negative IFA before vaccine given, also the IFA positive rates were not statistically different in these groups. There were no statistical differences of IFA GMT and IFA sero-negative rate between vaccine group and control group. CONCLUSIONS: The investigation showed there was no statistical difference in antibody level between vaccine group and control group, so there could not be enhancement of subclinical infection of vaccine group receiving type B inactivated vaccine against HFRS.

Adolescent↗
PubMed2000

A novel mutation in the NADH-cytochrome b5 reductase gene of a Chinese patient with recessive congenital methemoglobinemia.

Recessive congenital methemoglobinemia due to nicotinamide adenine dinucleotide (NADH)-cytochrome b5 reductase (b5R) deficiency is classified into 2 clinical types: type 1 (erythrocyte type) and type 2 (generalized type). We found a Chinese family with type 1 recessive congenital methemoglobinemia, the patients from which were diagnosed according to clinical symptoms and b5R enzyme activity in the blood cells. To learn the molecular basis of type 1 recessive congenital methemoglobinemia in this Chinese family, we isolated total RNA from the peripheral leukocytes of the propositus and b5R complementary DNA (cDNA) by reverse transcription- polymerase chain reaction (RT-PCR). The coding region of the b5R cDNA was analyzed by sequencing the cloned PCR products. The results showed that the propositus was homozygous for a G-->A transition at codon 203 in exon 7, changing a cysteine to a tyrosine (Cys203Tyr). To characterize the mutant enzyme, both glutathione S-transferase (GST)-fused wild-type b5R and GST-fused mutant Cys203Tyr b5R were expressed in Escherichia coli and affinity purified. The results showed that the catalytic activity of the enzyme was not much affected by this amino acid substitution, but the mutant enzyme exhibited decreased heat stability and increased susceptibility to trypsin. These properties of the mutant enzyme would account for the restricted b5R deficiency and mild clinical manifestations of these type 1 patients. The finding of this novel mutation makes codon 203 the only position within the b5R gene at which more than 1 mutation has been found.

Aged↗
PubMed2000

Embryonic and genetic manipulation in fish.

Fishes, the biggest and most diverse community in vertebrates are good experimental models for studies of cell and developmental biology by many favorable characteristics. Nuclear transplantation in fish has been thoroughly studied in China since 1960s. Fish nuclei of embryonic cells from different genera were transplanted into enucleated eggs generating nucleo-cytoplasmic hybrids of adults. Most importantly, nuclei of cultured goldfish kidney cells had been reprogrammed in enucleated eggs to support embryogenesis and ontogenesis of a fertile fish. This was the first case of cloned fish with somatic cells. Based on the technique of microinjection, recombinant MThGH gene has been transferred into fish eggs and the first batch of transgenic fish were produced in 1984. The behavior of foreign gene was characterized and the onset of the foreign gene replication occurred between the blastula to gastrula stages and random integration mainly occurred at later stages of embryogenesis. This eventually led to the transgenic mosaicism. The MThGH-transferred common carp enhanced growth rate by 2-4 times in the founder juveniles and doubled the body weight in the adults. The transgenic common carp were more efficient in utilizing dietary protein than the controls. An "all-fish" gene construct CAgcGH has been made by splicing the common carp beta-actin gene (CA) promoter onto the grass carp growth hormone gene (gcGH) coding sequence. The CAgcGH-transferred Yellow River Carp have also shown significantly fast-growth trait. Combination of techniques of fish cell culture, gene transformation with cultured cells and nuclear transplantation should be able to generate homogeneous strain of valuable transgenic fish to fulfil human requirement in 21st century.

Animals↗
PubMed2000

'In vitro evolution' of ligands for HCV-specific serum antibodies.

We developed a strategy to improve the properties of ligands selected from phage-displayed random peptide libraries. A site-directed mutagenesis protocol that introduces mutations and extends the size of a target sequence has been set up to generate diversity in a single or in a population of clones. The pool of mutants thus created is screened to identify variants with the desired properties. We refer to this strategy as in vitro evolution' of ligands. Here we report the application of this in vitro evolution protocol to the identification of improved ligands for HCV-specific serum antibodies. A single clone or population of clones were processed to generate a secondary library. Screening of these libraries with sera from HCV-infected patients identified peptides with an enhanced and broadened ability to detect HCV-specific serum antibodies.

Antibodies, Viral↗
PubMed2000

[Electroporation of sperm to introduce foreign DNA into the genome of Pinctada maxima (Jameson)].

Gene transfer was investigated in marine molluscs via electroporated sperm. Sperm of P. maxima (J.) was incubated with linear "all-fish" growth hormone gene (pCAgcGH and pCAgcGHc) for 30 min. Then, mature eggs were in-vitro fertilized with the sperm cells treated with electroporation at 10 kV and 2(7) pulses of six cycles. DNA was extracted from spat and analyzed by PCR and southern blot. The results indicated that the foreign DNA had been transferred into the genome of experimental molluscs. The transgenetic ration was 5.6%, 20% and 50% when 2 micrograms/mL, 6 micrograms/mL and 18 micrograms/mL of foreign DNA was used, respectively. It is suggested that the transferred efficiency is correlated with the amount of the foreign DNA.

Animals↗
PubMed2000

A compound heterozygote in the NADH-cytochrome b5 reductase gene from a Chinese patient with hereditary methemoglobinemia type I.

To elucidate the mutation in the nicotinamide adenine dinucleotide-cytochrome b5 reductase (b5R) gene from a Chinese patient with hereditary methemoglobinemia type I, we analyzed the coding sequences of b5R cDNA from the patient and from normal subjects by direct sequencing the reverse transcriptase-polymerase chain reaction (RT-PCR) products. The PCR-amplified genomic DNA fragments of the b5R gene from the patient, his mother, and normal controls were analyzed by restriction enzymes MspI and RsaI. A compound heterozygote Arg57Gln (CGG-->CAG)/Cys203Tyr (TGC-->TAC) was found in the b5R gene from the patient, and a CGG-->CAG mutant allele occurred in a chromosome inherited from his mother, while TGC-->TAC occurred in a chromosome inherited from his father. In this report, we discuss a compound heterozygote first observed in the b5R gene from a patient with hereditary methemoglobinemia type I.

Adolescent↗
PubMed2000

[A survey on botanical origins of drug Xue Lianhua produced in China].

OBJECTIVE: Based on an to investigation and identification of commercial samples to find out the original species and resources of Xue Lianhua. METHOD: Botanical and macroscopical identification. RESULT: The main original species of the plant are Saussurea involucrata, S. medusa, S. gossypiphora, S. polylada, S. laniceps, S. tridactyla, S. gnaphaloides, S. kingii, S. obvallata, S. tangutica, S. globosa, S. longifolia, Soroseris erysimoides, So. glomerata and So. umbrella. CONCLUSION: The flower and stem of S. involucrata and S. polylada and the whole herb of S. medusa and S. gossypiphora are used as Xue Lianhua in most areas of China.

Asteraceae↗
PubMed1999

Atom density in protein structures.

The residue environment in protein structures is studied with respect to the density of carbon (C), oxygen (O), and nitrogen (N) atoms within a certain distance (say 5 A) of each residue. Two types of environments are evaluated: one based on side-chain atom contacts (abbreviated S-S) and the other based on all atom (side-chain + backbone) contacts (abbreviated A-A). Different atom counts are observed about nine-residue structural categories defined by three solvent accessibility levels and three secondary structure states. Among the structural categories, the S-S atom count ratios generally vary more than the A-A atom count ratios because of the fact that the backbone (O) and (N) atoms contribute equal counts. Secondary structure affects the (C) density for the A-A contacts whereas secondary structure has little influence on the (C) density for the S-S contacts. For S-S contacts, a greater density of (O) over (N) atom neighbors stands out in the environment of most amino acid types. By contrast, for A-A contacts, independent of the solvent accessibility levels, the ratio (O)/(N) is approximately 1 in helical states, consistent with the geometry of alpha-helical residues whose side-chains tilt oppositely to the amino to carboxy alpha-helical axis. The highest ratio of neighbor (O)/(N) is achieved under solvent exposed conditions. This (O) vs. (N) prevalence is advantageous at the protein surface that generally exhibits an acid excess that helps to enhance protein solubility in the cell and to avoid nonspecific interactions with phosphate groups of DNA, RNA, and other plasma constituents.

Protein Conformation↗
PubMed1999

PSMA mimotope isolated from phage displayed peptide library can induce PSMA specific immune response.

Prostate-specific membrane antigen (PSMA) is a cell surface glycoprotein expressed predominantly in prostate secretory acinar epithelium and prostate cancer cells as well as in several extraprostatic tissues. Mouse monoclonal antibody 4G5 specific to the extracellular domain of PSMA was used to screen two phage displayed peptide libraries (9aa linear and 9aa cys library). Three 4G5-reactive phagotopes were identified. Sequence analysis of isolated clones demonstrated that the interaction motif "VDPA/SK" has high homology to 719-725aa on PSMA. Immunohistochemical staining of the prostate cancer sample with the PSMA-mimic phagotope (mimotope) immunized serum antibodies demonstrate that the mimotope isolated from the phage displayed peptide libraries can induce PSMA specific immune response in vivo.

Animals↗
PubMed1998

Extended metal environments of cytochrome c oxidase structures.

The metals of the cytochrome c oxidase structures of the bovine heart mitochondrion (PDB code 1occ) and of the soil bacterium Paracoccus denitrificans (1arl) include a dicopper center (CuA), magnesium, two proximal hemes, a copper (CuB) atom, and a calcium. The mitochondrial structure also possesses a bound distant zinc ion. The extended environments of the metal sites are analyzed emphasizing residues of the second shell in terms of polarity, hydrophobicity, secondary structure, solvent accessibility, and H-bonding networks. A significant difference in the CuA metal environments concerns D-51 I in 1occ, absent from 1arl. The D-51 I appears to play an important role in the proton pumping pathway. Our analysis uncovers several statistically significant residue clusters, including a cysteine-histidine-tyrosine cluster overlapping the CuA-Mg complex; a histidine-acidic cluster enveloping the environment of Mg, the two hemes, and CuB; and on the protein surface a mixed charge cluster, which may help stabilize the quaternary structure and/or mediate docking to cytochrome c. These clusters may constitute possible pathways for electron transfer, for O2 diffusion, and for H2O movement. Many hydrogen bonding relations along the interface of subunits I and II demarcate this surface as a potential participant in proton pumping.

Amino Acid Sequence↗
PubMed1998

Antibody-based spot test for NADH-cytochrome b5 reductase activity for the laboratory diagnosis of congenital methemoglobinemia.

NADH (reduced Coenzyme I)-cytochrome b5 reductase (b5R) is a multifunctional redox enzyme, whose deficiency causes recessive congenital methemoglobinemia. A novel procedure for the detection of b5R activity in human hemolysates was developed, in which b5R monoclonal antibodies dot-blotted on nitrocellulose membrane was used to capture and enrich b5R from hemolysates, and the captured b5R activity was subsequently visualized with the substrate 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide. Application of this simple method to the detection of b5R activity in the hemolysates from different subjects demonstrated that it was both sensitive and reliable. Our method would be useful for the laboratory diagnosis of congenital methemoglobinemia.

Adult↗