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Biomedical subjects

Z Deng

Publications and source records attributed to Z Deng.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Effects of antisense human telomerase RNA on growth of human gastric cancer cells].

OBJECTIVE: To observe the inhibitory effects of antisense human telomerase RNA (hTR) on growth of human gastric cancer cells. METHODS: SGC7901 cell line was transfected with antisense hTR expression vector (pBBS-hTR) by lipofectAMINE. The gene transfected cells were cultured in vitro and then inoculated into nude mice. RESULTS: Antisense hTR expression was enhanced and sense hTR expression inhibited in clones containing antisense hTR after hygromycin resistant selection which induced tumor cells apoptosis. The growth rate of the major gene transfected cells in culture and tumorigenesis of the transfected cells in nude mice were significantly reduced in comparison with those of controls. The survival time of nude mice inoculated with the gene transfected cells was markedly prolonged when compared to controls. CONCLUSIONS: The malignant proliferation of gastric cancer cell can be reversed by antisense hTR induced cell apoptosis. Thus antisense hTR may serve as a potential therapeutic approach to the treatment of human cancer.

Animals↗
PubMed2000

[Transfer of two large linear plasmids pHZ1000 and pHZ1001 by conjugation from Streptomyces T8-4 to S. lividans ZX1].

Using pulsed-field gel electrophoresis (PFGE), two indigenous large plasmids were isolated from Streptomyces T8-4. Two dimentional PFGE revealed that both plasmids were linear molecules. By parallel electrophoresis with linear plasmids of known sizes, the two linear plasmids were estimated to be approximately 230 kb and 90 kb, which were designated as pHZ1000 and pHZ1001, respectively. Both plasmids could be transferred into S. lividans ZX1 by conjugation, which is detectable by "pock" formation. Five S. lividans ZX1 derivatives which carry one or two plasmids were isolated and characterized by Southern hybridization and PFGE.

Conjugation, Genetic↗
PubMed2000

[Influence of substituents on IR spectrum of aromatic amines in different solvents].

The 21 aromatic amines in different solvents are studied by FTIR, and the influence of substituents on the vibrational absorption, symmetric stretching frequency(nu s) and anti-symmetric stretching frequency(nu as) is investigated. The substituent of methyl has different electrical effects in organic solvent with various polarities. The electric effects of methoxy in ortho-position differ from that in meso-position. The functional groups of chloro- and nitro-cause the nu as and nu s of amino group a hyposochromic shift, while substituent of-NH2 makes the nu as and nu s of amino group a bathochromic shift.

Amines↗
PubMed1999

Expression, characterization, and crystallization of the pyrophosphate-dependent phosphofructo-1-kinase of Borrelia burgdorferi.

The two genes for the putative pyrophosphate-dependent phosphofructokinases (PPi-PFKs) of Borrelia burgdorferi were cloned by PCR and expressed in Escherichia coli, and their protein products were purified to near homogeneity. The larger of the two gene products, a 62-kDa protein, is an active PPi-PFK and exists in solution as a dimer. It has apparent K(m) values for fructose 6-P and PPi of 109 and 15 microM, respectively, and a pH optimum of 6.4 to 7.2. The 62-kDa protein was crystallized and subjected to preliminary diffraction analysis. The smaller gene product, a 48-kDa protein, exists in solution as a higher polymer and shows no ATP- or PPi-dependent activity, despite having a secondary structure as estimated by circular dichroism that is not significantly different from that of other PFKs.

Animals↗
PubMed1999

Identification and characterization of a zinc finger gene (ZNF213) from 16p13.3.

During our search for the familial Mediterranean fever (FMF) gene, we identified by cDNA selection a 1.2 kb cDNA fragment representing a novel human gene that is expressed in a wide variety of tissues. This gene spans approx. 8.0 kb genomic DNA and has seven exons. Its 3' untranslated region contains a long tandem repeat that gives rise to a polymorphism with two alleles of approx. 1.1 kb and 1.0 kb, with the 1.1 kb allele in strong linkage disequilibrium with FMF in patients of different ethnic backgrounds. However, both genetic and mutational analyses have excluded this gene as the one responsible for FMF. The predicted 424 amino acid protein, designated ZNF213, contains three C2H2 zinc fingers, a Kruppel associated A box and a leucine rich motif (LeR domain/SCAN box), strongly suggestive of a transcription factor.

Amino Acid Sequence↗
PubMed1999

A productive NADP+ binding mode of ferredoxin-NADP + reductase revealed by protein engineering and crystallographic studies.

The flavoenzyme ferredoxin-NADP+ reductase (FNR) catalyzes the production of NADPH during photosynthesis. Whereas the structures of FNRs from spinach leaf and a cyanobacterium as well as many of their homologs have been solved, none of these studies has yielded a productive geometry of the flavin-nicotinamide interaction. Here, we show that this failure occurs because nicotinamide binding to wild type FNR involves the energetically unfavorable displacement of the C-terminal Tyr side chain. We used mutants of this residue (Tyr 308) of pea FNR to obtain the structures of productive NADP+ and NADPH complexes. These structures reveal a unique NADP+ binding mode in which the nicotinamide ring is not parallel to the flavin isoalloxazine ring, but lies against it at an angle of approximately 30 degrees, with the C4 atom 3 A from the flavin N5 atom.

Amino Acid Sequence↗
PubMed1999

Study on pathogenic mechanism of emotions in traditional Chinese medicine--an observation of hydrogen peroxide releasing function of celiac macrophages in rats under stress state.

The hydrogen peroxide releasing function of macrophages in rats under the stress state was observed with the animal model of "excessive anger impairing the liver". The results showed that the volume of hydrogen peroxide released from the macrophages in rats was decreased, while the corticosterone level in plasma increased after stress. It indicates that stimulation of harmful emotions could cause inhibition of immunoreaction of the organism, which might be related to the enhancement in excitability of the hypothalamus-pituitary-adrenal axis and hypersecretion of glucocorticoid hormone.

Animals↗
PubMed1999

Replacement vectors for localized gene cloning in the specified region of Streptomyces lividans 66 and model method for the screening of desired recombinants via counter-selection.

Two DNA fragments (3.5 kb and 3.8 kb in size) flanking both ends of the phi HAU3R gene in the genome of Streptomyces lividans 66 were determined and cloned in their natural relative orientations in pIJ653, a cosmid vector derived from the multi-copy Streptomyces plasmid pIJ101, resulting in pHZ806. After insertion of spectinomycin/streptomycin (spc/str) resistance gene into the pIJ101 replication region in pHZ806 and insertion of a hygromycin (hyg) resistance gene between 3.5 kb and 3.8 kb DNA fragments, a new vector with a non-functional Streptomyces replicon, pHZ808, was obtained. In principle, any DNA fragment cloned between 3.5 kb and 3.8 kb fragments of this vector can be stably integrated between the two corresponding regions after introduction into the wild-type S.lividans strains, with synchronous replacement of the DNA between the two regions of the chromosome within which phi HAU3R gene is located. The resultant recombinant strains will thus become phi HAU3-sensitive (phi HAU3S). This phenotype could serve as a good indication that the desired gene replacement has occurred. This principle was demonstrated to be successful using pHZ808 as vector. phi HAU3-resistance gene (phi HAU3R) from the genome of S.lividans 66 was substituted by the hygromycin resistance gene (hyg) from pHZ808. An additional advantage of using pHZ808 as the vector to clone foreign genes is that hyg could be served as a reportor gene to imply that foreign DNA fragment has been co-integrated with hyg. The recombinants will have both hygR and phi HAU3S.

Anti-Bacterial Agents↗
PubMed1999

[The effects of L-arginine and nimodipine on the expression of monocyte chemoattractant protein-1 in endothelial cells induced by lipopolysaccharide].

OBJECTIVE: To examine the effects of L-arginine and nimodipine on the expression of monocyte chemoattractant protein-1 (MCP-1) mRNA and protein induced by lipopolysaccharide (LPS) in endothelial cells (ECs). METHODS: After 8-hour exposure to LPS, LPS + L-arginine and LPS + nimodipine respectively, the total RNA in ECs was extracted by the guanidinium isothiocyanate method. The MCP-1 mRNA expression in ECs was examined by Dot blot analysis using a gamma-32P-end-labeled 35 mer oligonucleotide probe of MCP-1. MCP-1 protein in the EC-conditioned media (EC-CM) was determined by sandwich ELISA for each group. The expression of MCP-1 protein in ECs was examined immunocytochemically. RESULTS: Dot blotting showed that after exposure to LPS, the integral absorbance (A) value of the dots of MCP-1 mRNA on the nitrocellulose membrane were 3.14, which was 2.5-fold as much as that in the control group (A = 1.24). The A values of the LPS + L-arginine group and the LPS + nimodipine group were 1.43 and 1.65, respectively. ELISA showed that the MCP-1 protein content in the EC-CM of the LPS group was 6.29 +/- 0.53 ng/ml, which was markedly higher than that of the control group (2.32 +/- 0.16) ng/ml (P < 0.01). The MCP-1 protein content in the EC-CM of the LPS + L-arginine group and the LPS + nimodipine group was significantly lower than that of the LPS group (P < 0.01). Furthermore, the ECs in LPS group showed a strong immunoreactivity for the polyclonal MCP-1 antibody, whereas the ECs in control, L-arginine and nimodipine groups revealed a weak postive immunostaining. CONCLUSION: L-arginine and nimodipine can markedly inhibit the expression of MCP-1 in ECs induced by LPS.

Animals↗
PubMed1999

[Clinical study on treatment of rectal carcinoma with Chinese herbal medicine and high dose fluorouracil emulsion via rectal infusion].

OBJECTIVE: To study the clinical significance of rectal infusion of Chinese herbal medicine (CHM) plus high dose fluorouracil emulsion in treating rectal carcinoma. METHODS: The 86 patients of rectal carcinoma were randomly divided into CHM plus chemotherapy group and single chemotherapy group, and the changes of T-lymphocyte cell subset, natural killer (NK) activity, pathologic picture and clinical symptoms were analysed statistically before and after treatment. RESULTS: In the single chemotherapy group, the CD3 cell and NK activity decreased after treatment and most of the peri-carcinoma cellular infiltration were in grade I. In the CHM plus chemotherapy group, the CD3, CD4/CD8 and NK activity restored and CD8 lymphocyte decreased markedly after treatment in comparing with those before treatment (P < 0.05, P < 0.01), and most of the peri-carcinoma cellular infiltration concentrated in grade III. CONCLUSION: Chemotherapy alone could suppress cellular immune function significantly, significant immunoregulation and improvement of symptoms (as mucous-bloody stool, frequent defecation) could be obtained by combination therapy of CHM and chemotherapy.

Adenocarcinoma↗
PubMed1999

[Neural network approach to medical grading of rheumatoid arthritis].

A grading system based on neural network has been developed and used int he medical grading diagnosis of a case group of Rheumatoid Arthritis presenting Cold syndrome intermingled with Heat syndrome. The possibility of using neural network in TCM diagnosis is preliminarily explored in this paper.

Algorithms↗
PubMed1999

[Study on proteins of allele by using the microisoelectric focusing].

Clear protein electrophoresis pattern of single pollen grain from Cucurbita pepo L. was obtained with isoelectric focusing and supersensitive stain technique. The results showed that there were two special distributing protein bands near acidity pole. In species I, the two protein bands were a little near to acidity pole and in species II, that was a little far from acidity pole. In species III, the two protein bands distributed either like species I or like species II and the distributed ratio was 1:1. Moreover, we discuss how to identify relative purity of gene with the sorts of the special proteins.

Alleles↗
PubMed1999

[The 1. 54 microm laser and upconversion luminescence of YELPP noncrystalline induced by 969 nm LD laser].

In this paper, the absorption of Er3+, Yb3+ penta-phosphate noncrystalline (YELPP) was measured and the basic spectral parameters were calculated. Adopting the longitudinal-pump method with a domestic diode laser (LD), we achieved CW 1.5 microm chipped laser in China for the first time. The power of 1.5 microm laser was quite stable. The target of 1.5 microm laser reached the international level of early 1990s' in this field. In addition, the up-conversion luminescence was measured under the condition that 1.5 microm laser was either oscillating or not. The relationship between 1.5 microm chipped laser and up-conversion luminescence was analyzed initially.

English Abstract↗
PubMed1998

Probing the function of the invariant glutamyl residue 312 in spinach ferredoxin-NADP+ reductase.

Ferredoxin-NADP+ reductase, the prototype of a large family of structurally related flavoenzymes, pairs single electrons carried by ferredoxin I and transfers them as a hydride to NADP+. Four mutants of the enzyme, in which Glu-312 was replaced with Asp, Gln, Leu, and Ala to probe the role of the residue charge, size, and polarity in the enzyme activity, have been heterologously expressed, purified, and characterized through steady-state, rapid kinetic studies, ligand-binding experiments, and three-dimensional structure determination by x-ray crystallography. The E312L mutant was the only one that was almost inactive (approximately 1%), whereas unexpectedly the E312A reductase was 10-100% active with the various acceptors tested. Rapid kinetic absorption spectroscopy studies demonstrated that flavin reduction by NADPH was impaired in the mutants. Furthermore, NADP(H) binding was partially perturbed. These functional and structural studies lead us to conclude that Glu-312 does not fulfil the role of proton donor during catalysis, but it is required for proper binding of the nicotinamide ring of NADP(H). In addition, its charge modulates the two one-electron redox potentials of the flavin to stabilize the semiquinone form.

Amino Acid Sequence↗
PubMed1998

On the active site of Old Yellow Enzyme. Role of histidine 191 and asparagine 194.

Old Yellow Enzyme (OYE) binds phenolic ligands forming long wavelength (500-800 nm) charge-transfer complexes. The enzyme is reduced by NADPH, and oxygen, quinones, and alpha,beta-unsaturated aldehydes and ketones can act as electron acceptors to complete catalytic turnover. Solution of the crystal structure of OYE1 from brewer's bottom yeast (Fox, K. M., and Karplus, P. A. (1994) Structure 2, 1089-1105) made it possible to identify histidine 191 and asparagine 194 as amino acid residues that hydrogen-bond with the phenolic ligands, stabilizing the anionic form involved in charge-transfer interaction with the FMN prosthetic group. His-191 and Asn-194 are also predicted to interact with the nicotinamide ring of NADPH in the active site. Mutations of His-191 to Asn, Asn-194 to His, and a double mutation, H191N/N194H, were made of OYE1. It was not possible to isolate the N191H mutant enzyme, but the other two mutant forms had the expected effect on phenolic ligand binding, i.e. decreased binding affinity and decreased charge-transfer absorbance. Reduction of the H191N mutant enzyme by NADPH was similar to that of OYE1, but the reduction rate constant for NADH was greatly decreased. The double mutant enzyme had an increased rate constant for reduction by NADPH, but the reduction rate constant with NADH was lower by a factor of 15. The reactivity of OYE1 and the mutant enzymes with oxygen was similar, but the reactivity of 2-cyclohexenone was greatly decreased by the mutations. The crystal structures of the two mutant forms showed only minor changes from that of the wild type enzyme.

Amino Acid Sequence↗
PubMed1998

Identification of two Krüppel-related zinc finger genes (ZNF200 and ZNF210) from human chromosome 16p13.3.

During the course of cloning the gene for familial Mediterranean fever (FMF), we identified a number of transcripts from a 275-kb genomic region on 16p13.3. Two of the transcripts were found to contain multiple C2H2-type zinc finger motifs in tandem arrays, indicating that they are members of the Krüppel-type family. One transcript was found to be an alternatively spliced form of a previously reported zinc finger gene, ZNF200. The other transcript, ZNF210, is 2017 bp and encodes an open reading frame of 504 aa. Northern blot analysis indicates that ZNF210 is expressed in all the tissues tested with the highest expression in heart, skeletal muscle, pancreas, prostate, ovary, and colon. On the other hand, the strongest expression of ZNF200 is in testis, with very low levels in all the other tissues tested. Sequence analysis reveals eight C2H2 zinc finger motifs at the C-terminus of ZNF210 and five in ZNF200. In addition, ZNF210 also possesses a Krüppel-associated box at its N-terminus, indicating that it might function as a transcription repressor. The intron-exon structures of both genes were determined and showed that ZNF210 has seven exons while the coding part of ZNF200 is distributed in four exons. The locations of ZNF200 and ZNF210 are 10 and 120 kb telomeric to the FMF gene, respectively.

Amino Acid Sequence↗
PubMed1998

Diagnosis of familial Mediterranean fever by a molecular genetics method.

BACKGROUND: Familial Mediterranean fever is a recessively inherited disorder characterized by episodes of fever with abdominal pain, pleurisy, or arthritis. The familial Mediterranean fever gene, designated MEFV, was recently cloned, and at least three missense mutations (M6801, M694V, and V726A) that account for a large percentage of patients with this disease were identified. OBJECTIVE: To establish a diagnostic test for familial Mediterranean fever. DESIGN: Cross-sectional study of a convenience sample of patients attending familial Mediterranean fever clinics. SETTING: Tertiary referral hospitals. PATIENTS: 107 patients with familial Mediterranean fever, their family members, and controls. MEASUREMENTS: Mutations in the 107 samples were assessed by amplifying genomic DNA with use of primers that selectively amplify the normal or altered DNA sequence of the 3 MEFV mutations (amplification refractory mutation system [ARMS]). Mutations were independently assessed by automated sequencing of genomic DNA amplified by polymerase chain reaction to evaluate the sensitivity and specificity of the ARMS assay. RESULTS: The ARMS assay correctly identified M6801, M694V, and V726A mutations in 82 persons with mutations documented by DNA sequencing (21 homozygotes, 2 compound heterozygotes, and 59 simple heterozygotes). Of 7 persons known from family studies to be noncarriers and 18 unrelated persons who were negative for these mutations by sequencing, none had MEFV mutations according to ARMS. CONCLUSION: The ARMS assay is a rapid, cost-effective, and accurate method for detecting three common mutations in familial Mediterranean fever.

Cross-Sectional Studies↗