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Y Qi

Publications and source records attributed to Y Qi.

At least 91 records · Page 5Linked to original sources
PubMed1999

Isolation of an apoptosis suppressor gene of the Spodoptera littoralis nucleopolyhedrovirus.

Spodoptera frugiperda SF9 cells infected with mutants of the Autographa californica nucleopolyhedrovirus (AcMNPV) which lack a functional p35 gene undergo apoptosis, aborting the viral infection. The Spodoptera littoralis nucleopolyhedrovirus (SlNPV) was able to suppress apoptosis triggered by vDeltaP35K/pol+, an AcMNPV p35 null mutant. To identify the putative apoptotic suppressor gene of SlNPV, overlapping cosmid clones representing the entire SlNPV genome were individually cotransfected along with genomic DNA of vDeltaP35K/pol+. Using this complementation assay, we isolated a SlNPV DNA fragment that was able to rescue the vDeltaP35K/pol+ infection in SF9 cells. By further subcloning and rescue, we identified a novel SlNPV gene, Slp49. The Slp49 sequence predicted a 49-kDa polypeptide with about 48.8% identity to the AcMNPV apoptotic suppressor P35. SLP49 displays a potential recognition site, TVTDG, for cleavage by death caspases. Recombinant AcMNPVs deficient in p35 bearing the Slp49 gene did not induce apoptosis and showed successful productive infections in SF9 cells, indicating that Slp49 is a functional homologue of p35. A 1.5-kbp Slp49-specific transcript was identified in SF9 cells infected with SlNPV or with vAc496, a vDeltaP35K/pol+-recombinant bearing Slp49. The discovery of Slp49 contributes to the identification of important functional motifs conserved in p35-like apoptotic suppressors and to the future isolation of p35-like genes from other baculoviruses.

Amino Acid Sequence↗
PubMed1999

[Computerized ribosomal RNA secondary structure modeling of mutants found in Rett syndrome patients and their mothers].

OBJECTIVE: To identify the secondary structure of rRNA mutants, mtDNA2835(C-->T) and mtDNA2706(A-->G) found in Rett syndrome patients and their mothers. METHODS: Both wild type mtDNA sequence of rRNA gene and mutated sequence were input into computer (converted into RNA sequences) and analyzed by the sofware DNASIS v6. 14. The unique prediction size is set 300 bases and the maximum bulge and interior loop size,30 bases. RESULTS: Similar to the positive controls, the mtDNA2835(C-->T) made the 16S rRNA secondary structure totally different,and the energy changes a lot. On the contrary, the mtDNA2706(A-->G) altered little of secondary structure with a small energy shift. CONCLUSION: Computerized folding programs have provided us with a quick prediction of rRNA structure changes induced by these two mutations. Of them, the mtDNA2835(C-->T) might relate to the pathogenesis of Rett syndrome, but the mtDNA2706(A--> G) might be less meaningful.

Computer Simulation↗
PubMed1999

[The genotype-based haplotype relative risk and transmission disequilibrium test analyses of familial febrile convulsions].

OBJECTIVE: To confirm the linkage of familial febrile convulsions to the short arm of chromosome 6(6p) or the long arm of chromosome 8(8q). METHODS: The authors finished genotyping of Pst I locus on the coding region of heat shock protein (HSP) 70, 5'untranslated region of HSP70-1, 3' untranslated region of HSP70-2, D8S84 and D8S85. The data were processed by the genotype-based haplotype relative risk(GHRR) and transmission disequilibrium test(TDT) methods in PPAP. RESULTS: Some signs of association and disequilibrium between D8S85 and FC were shown by GHRR and TDT. CONCLUSION: A suspect linkage of familial febrile convulsions to the long arm of chromosome 8 has been proposed.

Chromosomes, Human, Pair 6↗
PubMed1999

Corneal topographic analysis after excimer photorefractive keratectomy.

OBJECTIVE: To evaluate the corneal surface changes and visual quality after excimer photorefractive keratectomy (PRK) for myopia. METHODS: Corneal topographic analysis was performed on 23 patients (38 eyes) with myopia after PRK at the 1-, 3-, 6- month postoperative follow-up visits. RESULTS: The corneal sphericity was changed after excimer PRK. As time went on, the mean surface regularity index (SRI) and the surface asymmetry index (SAI) decreased gradually, and the corneal surface became more smooth; mean simulated keratoscope readings (SimK) showed a gradual restoration. At the 6-month postoperative examination, corneal topography showed four main patterns of ablation: round or oblong (50%), collar-button (23.68%), semicircular (18.42%) and central island (7.9%). Patterns of ablation were correlated with visual acuity. CONCLUSION: The quantitative analysis of corneal topography is essential for evaluating corneal surface changes after PRK and helpful in the surgical design of PRK and in predicting the refractive outcome with greater precision.

Adolescent↗
PubMed1999

[Influence of blood-activating drugs on adhesion and invasion of cells in lung cancer patients].

OBJECTIVE: To investigate the influence of some blood-activating drugs like Tetramethylpyrazine, Tanshinone II A, Hirudin and thrombin on adhesive and invasive behavior of PGCL3 and PAa cell lines. METHODS: Using the above-mentioned blood-activating drugs in various concentration to treat PGCL3 and PAa cells, and the changes in adhesion to fibronectin and invasion in Boyden Chamber of these cells, alone or after interacted with human platelets, were observed. RESULTS: Tetramethylpyrazine, Hirudin and thrombin could increase the adhesion of cells to fibronectin and Tanshinone II A decrease it. Tetramethylpyrazine, Tanshinone II A and Hirudin inhibited the invasion of PGCL3 cells in Boyden Chamber, and thrombin augmented the process. CONCLUSION: The blood-activating drugs may either inhibit or promote the invasion and metastasis of PGCL3 and PAa cells in the light of various conditions.

Adenocarcinoma↗
PubMed1999

[The immunohistochemical changes of TGF-beta, type I and III collagen in corneal healing after photorefractive keratectomy].

OBJECTIVE: To observe the immunohistochemical expression of transforming growth factor-beta (TGF-beta), type I and III collagen in monkey corneal healing after photorefractive keratectomy (PRK) and find whether TGF-beta is involved in the process of corneal healing and correlated with the syntheses of type I and III collagen. METHODS: Three rhesus monkeys (6 eyes) were operated for myopic ablation of 10.0 diopters. The depth of ablation was 103 microm. Microscopy, transmission electron microscopy and immunohistochemistry were performed at 1, 3 and 6 months after PRK. RESULTS: TGF-beta staining was positive in the epithelium and a few fibroblasts under the epithelium at one month after the operation. The staining was negative at 6 months and in the control specimens. Postoperatively, type I and III collagen stainings were evident at 1, 3 and 6 months. Type I collagen staining was positive and type III was negative in the controls. CONCLUSION: TGF-beta is involved in the corneal healing after PRK, and perhaps correlated with the syntheses of type I and III collagen.

Animals↗
PubMed1999

[Light-dependent incorporation of selenite into selenocysteine by isolated chromatophore of Chromatium vinosum].

Illiminated intact chromatophore of chromatium vinosum in the presence of O-acetylserine(OAS) catalysed incorporation of SeO3(2-) into selenocysteine at rate of 359 nmol.mgBchl-1.h-1. Sonicated chromatophore catalysed SeO3(2-) incorporation at 1.1% of the rate of intact chromatophore. Addition of GSH and NADPH increased the rate to 88.3% of intact rate, but SeO3(2-) incorporation under these conditions was essentially light dependent. The purified GSH reductase from Chromatium vinosum in the presence of cysteine synthase OAs and NADPH catalysed incorporation of SeO3(2-) into selenocysteine. It is proposed that SeO3(2-) is reduced by light-coupled GSH reductase and that Se2- produced is incorporated into selenocysteine by cysteine synthase.

Catalysis↗
PubMed1999

[Aminoglycoside ototoxicity associated with mitochondrial DNA mutation].

OBJECTIVE: To confirm the effect of genetic susceptibility to aminoglycoside ototoxicity. METHOD: Mitochondrial DNA (mtDNA) from 62 members of 9 aminoglycoside induced deafness families was analysed by PCR-Restriction endonuclease digestion. RESULT: The nucleotide 1555A-->G mutation in 12S rRNA gene of mtDNA was identified in 20 members of 5 families. CONCLUSION: These findings indicate that this mutation is a molecular basis for genetic susceptibility to the ototoxic effect of aminoglycosides. The relationship between the audiovestibular changes and genetic susceptibility to aminoglycoside ototoxicity and the pathogenetic mechanism of susceptible deafness are discussed. The possibility that other gene mutations can also predispose to aminoglycoside ototoxicity is proposed.

Adolescent↗
PubMed1999

[The effects of sex hormone on blood vessels].

OBJECTIVE: The protective mechanism of sex hormone on blood vessels was investigated to provide evidences for clinical use of hormone replacement therapy in postmenopausal women. METHODS: To observe the effects of 17 beta-estradiol (E2), progesterone(P), testosterone (T) and E2 combined with P on the relaxation of umbilical arterial rings (UAR) as well as production of nitric oxide (NO) in cultured umbilical endothelial cells(HUVEC) in vitro. RESULTS: The results showed that 10(-9)-10(-6) mol/L E2 dilation of UAR, but 10(-5) mol/L E2 showed vague effect. P or T had no relaxation effect, but releasing nitric oxide. When in combined trial P at 10(-5) mol/L inhibited the relaxation effect of E2 at 10(-7)-10(-5) mol/L but didn't inhibit E2 10(-9) mol/L. In HUVEC 10(-9)-10(-5) mol/L E2 stimulated the release of nitric oxide when cells incubated for 10 min and 30 min, but did not influence the NO release at 60 min. P and T have different effects on the release of nitric oxide at different concentrations and incubation time. P also inhibited the NO release induced by E2. CONCLUSIONS: The results indicated that P actually inhibited the relaxation response and induction of NO release by E2, especially at the high concentration. Therefore, we suggested that to use low doses of E2 combined with low dose P for hormone replacement therapy in prevention and treatment of cardiovascular diseases in postmenopausal patient.

Cells, Cultured↗
PubMed1998

FK-binding protein is associated with the ryanodine receptor of skeletal muscle in vertebrate animals.

The ryanodine receptor/calcium release channel (RyR1) of sarcoplasmic reticulum from rabbit skeletal muscle terminal cisternae (TC) contains four tightly associated FK506-binding proteins (FKBP12). Dissociation and reconstitution studies have shown that RyR1 can be modulated by FKBP12, which helps to maintain the channel in the quiescent state. In this study, we found that the association of FKBP with RyR1 of skeletal muscle is common to each of the five classes of vertebrates. TC from skeletal muscle representing animals from different vertebrates, i.e. mammals (rabbit), birds (chicken), reptiles (turtle), fish (salmon and rainbow trout), and amphibians (frog), were isolated. For each, we find the following: 1) FKBP12 is localized to the TC (there are four FKBP binding sites/ryanodine receptor); 2) soluble FKBP exchanges with the bound form on RyR1 of TC; 3) release of FKBP from terminal cisternae by drug (FK590) treatment leads to a significant reduction in the net calcium loading rate, consistent with channel activation (the calcium loading rate is restored to the control value by reconstitution with FKBP12); and 4) RyR1 of skeletal muscle TC can bind to and exchange with either FKBP12 or FKBP12.6 (FKBP12.6 is the novel FKBP isoform found selectively associated with RyR2 of dog cardiac sarcoplasmic reticulum). We conclude that FKBP is an integral part of the RyR1 of skeletal muscle in each of the classes of vertebrate animals. The studies are consistent with a role for FKBP in skeletal muscle excitation-contraction coupling.

Animals↗
PubMed1998

Characterization of BRCA2: temperature sensitivity of detection and cell-cycle regulated expression.

People carrying a mutant BRCA2 gene are susceptible to breast, ovarian, pancreatic and other tumors. Many facets of BRCA2 have been studied, including its mutation in human cancers, its role in mouse embryogenesis and its RNA expression in different tissues and different mouse embryogenesis stages. However, there has been very little characterization of BRCA2 protein. We investigated the biochemical and biological properties of BRCA2 by using a monoclonal antibody we generated against the N-terminal portion of BRCA2. We discovered that the detection of BRCA2 by immunoblot analysis was sensitive to the temperature used to denature the samples before gel electrophoresis. BRCA2 was easily detectable when samples were denatured at low temperature instead of boiling. Although the precise mechanism underlying this observation is not clear yet, this finding will significantly improve our ability to study BRCA2. We examined the expression of BRCA2 using an immunoblot analysis protocol modified according to this observation. We showed that BRCA2 was presented in every human cell lines examined, including Capan-1, which expressed a truncated BRCA2 due to a BRCA2 frameshift mutation. We also showed that the expression of BRCA2 was cell-cycle regulated. Our results suggest that BRCA2 has an important role in cell growth regulation.

Antibodies, Monoclonal↗
PubMed1998

Specific interaction of Golgi coatomer protein alpha-COP with phosphatidylinositol 3,4,5-trisphosphate.

The phosphoinositide binding selectivity of Golgi coatomer COPI polypeptides was examined using photoaffinity analogs of the soluble inositol polyphosphates Ins(1,4,5)P3, Ins(1,3,4,5)P4, and InsP6, and of the polyphosphoinositides PtdIns(3,4,5)P3, PtdIns(4,5)P2, and PtdIns(3,4)P2. Highly selective Ins(1,3,4,5)P4-displaceable photocovalent modification of the alpha-COP subunit was observed with a p-benzoyldihydrocinnamide (BZDC)-containing probe, [3H]BZDC-Ins(1,3,4,5)P4. A more highly phosphorylated probe, [3H]BZDC-InsP6 probe labeled six of the seven subunits, with only beta, beta', delta, and epsilon-COP showing competitive displacement by excess InsP6. Importantly, [3H]BZDC-triester-PtdIns(3,4,5)P3, the lipid with the same phosphorylation pattern as Ins(1,3,4,5)P4, showed specific, PtdIns(3,4,5)P3-displaceable labeling of only alpha-COP. Labeling by the PtdIns(4,5)P2 and PtdIns(3,4)P2 photoaffinity probes was less intense and showed no discrimination based on PtdInsPn ligand. Thus, both the D-3 and D-5 phosphates are critical for the alpha-COP-PtdIns(3,4,5)P3 interaction, suggesting an important role for this polyphosphoinositide in vesicular trafficking.

Affinity Labels↗
PubMed1998

Antagonists of sensory neuropeptides inhibit the secondary phase of increased circulation following thermally induced inflammation.

A model of thermally induced inflammation in the anesthetized rat was used to measure acute microcirculatory reactions after heat exposure. The thermal injury was inflicted by dipping the right hindpaw into hot water at 60 degrees for 20 s. Local blood flow was recorded simultaneously in both hindpaws and continuously by laser Doppler flowmetry before, during and for 2 h after the thermal injury and the mean arterial blood pressure (MAP) was displayed on a chart recorder. To assess the contribution of the nervous system to the vascular changes seen, neuropeptide antagonists directed toward substance P (SP), neurokinin A (NKA), and calcitonin gene-related peptide (CGRP) were administered. The neurokinin antagonists (NK1, NK2) and the CGRP antagonist (CGRP8-37) were injected via a catheter into the jugular vein. During the first few minutes after thermal injury to the controls, an immediate increase in blood perfusion of about 351% was recorded, followed by a slow decrease of circulation. At 30 min after thermal injury, there was a secondary phase of increased microcirculation of approximately 329%. A slow decline of cutaneous circulation then followed and, after another 30 min, the value stabilized at a level about 100% above the level before injury. Pretreatment with intravenous injections of the NK1 antagonist, NK2 antagonist, and CGRP8-37 attenuated the first phase and almost abolished the secondary phase. No significant change of perfusion was observed on the unscalded paw. The MAP remained at a stable level throughout the experiment and was not affected by the thermal injury or by the administration of the antagonists as compared to controls. Our results show that sensory neuropeptides play a significant role in the blood flow increase seen following thermal injury.

Animals↗
PubMed1998

A novel expression system based on host-range expansion of baculovirus.

A host range expanded recombinant Autographa californica multiple-nucleocapsid nucleopolyhedrosis virus AcMNPV/r2 was obtained by cotransfection of the bacmid DNA from Escherichia coli DH10Bac along with a plasmid pBmH-M containing HindIII M fragment of Bombyx mori nuclear polyhedrosis virus (BmNPV) genomic DNA. A recombinant transposon vector carrying a mutant green fluorescent protein gene (GFP) and a polyhedrin gene was constructed. Transposition was carried out in both E. coli DH10Bac and E. coli DH10BmH, which contains AcMNPV/r2 and a helper plasmid. Recombinant DNAs were transfected into Sf-9 cells to generate recombinant virus AcMNPV/r3 and AcMNPV/r4 respectively. Viral stock of AcMNPV/r4 was then infected into Bombyx mori cells (BmN) and Bombyx mori larvae (silkworm). Analysis shows that GFP was highly expressed in Bombyx mori larvae. This expression system, is practicable therefore for mass production of foreign gene products.

Animals↗
PubMed1998

Specific inhibition of CD4+ T lymphocytes by a hybrid antibody.

T lymphocytes are crucial in the defense against foreign intruders and cancerous growths. Yet, in circumstances such as transplantation or autoimmunity, T-cell-mediated responses can be detrimental. Inhibition of these deleterious responses is currently achieved by drugs that induce general immune suppression. These compounds also impair the patient's defenses against infections. Strategies are now being sought that induce selective rather than generalized immune unresponsiveness. One such strategy is the ability to inhibit the activation of CD8+ T lymphocytes. As CD4+ T lymphocytes similarly participate in graft rejection and in autoimmune diseases, we have now developed a reagent to delete their activity. It comprises CD4 and an anti-MHC class II antibody. By virtue of the antibody's specificity for MHC class II molecules, this hybrid antibody (Hab) binds to class II molecules, thereby bringing CD4 accessory molecules to the surface of class II-bearing stimulator cells where they occupy CD4 binding sites on class II molecules. As a consequence CD4+ T cells with specificity to Hab-coated stimulator cells cannot engage their CD4 molecules and are no longer activated. This Hab technology provides a strategy to offer specific rather than generalized immune suppression.

Animals↗
PubMed1998

Sites internal to the coding regions of phoA and pstS bind PhoP and are required for full promoter activity.

Bacillus subtilis PhoP and PhoR, a pair of two-component regulatory proteins, regulate the phosphate starvation response. Here, we used two other pho regulon promoters, the phoA and pstS promoters, to examine the mechanism of PhoP-specific activation of its target promoters. Both gel shift and DNase I footprinting assays indicate that PhoP bound to the two promoters. Unphosphorylated PhoP bound only to the multiple TTAACA-like sequences upstream of these two promoters, while phosphorylated PhoP extended the binding region in both the 5' and the 3' direction and, additionally, protected sequences internal to the coding region of these two genes. The PhoP binding sites in the coding region were necessary for full induction from either promoter during phosphate starvation. Deletion of these sites eliminated approximately 75% and 45% of the induced promoter activity of the phoA and pstS promoters respectively. In vitro transcription assays using the phoA promoters with various 3' ends confirmed the requirement of the PhoP-P binding to the coding region for full promoter activity. The multiple TTAACA-like sequences in the phoA and pstS promoters were essential for promoter activity, and deletion of one or more of these sequences in either promoter eliminated the promoter activity. Two pairs of TTAACA-like sequences were required for efficient PhoP binding and were suggested to be one B. subtilis Pho box. Based on our data, we have proposed a model for activation of the phoA and the pstS promoter by PhoP.

Bacillus subtilis↗
PubMed1998

PhoP-P and RNA polymerase sigmaA holoenzyme are sufficient for transcription of Pho regulon promoters in Bacillus subtilis: PhoP-P activator sites within the coding region stimulate transcription in vitro.

The Bacillus subtilis pstS operon and phoA gene are members of the Pho regulon that is controlled by PhoR, a histidine kinase, and PhoP, a response regulator. Footprinting analysis showed that phosphorylated PhoP extended the PhoP protected region in pstS and phoA promoters, and also bound to a separate site within the coding region of each gene. Our previous in vivo studies have shown that, in contrast to other Pho regulon promoters that are not expressed in either phoP or phoR mutants, a low-level induction from the pstS promoter (25% of parent strain) can be detected in a phoR mutant. In this study, by using an in vitro transcription system, we demonstrate that (i) only phosphorylated PhoP is a transcriptional activator of the pstS operon and of the phoA gene; (ii) phosphorylated PhoP and RNA polymerase sigmaA holoenzyme are sufficient for in vitro transcription of the pstS promoter and the phoA promoter; (iii) the activation of the pstS promoter requires lower concentrations of phosphorylated PhoP than does the phoA promoter for transcription; and (iv) PhoP binding sites in both the pstS promoter core binding region and in the 5' coding region of the gene, which have been identified by footprinting analysis, are important for the transcription of the pstS promoter in vitro.

Alkaline Phosphatase↗