2101
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Wang L, Jiang W, Qian J. Hearing shift and inner ear pathology of guinea pigs exposed to octave bands of noise centered at 63 Hz and 4 kHz. Chin Med J (Engl) 1994; 107:500-4. [PMID: 7956496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Twenty-four guinea pigs with normal Preyer's reflex were exposed to the octave bands of noise centered at 63 Hz and 4 kHz, 110 dB SPL. The duration of exposure was 4 and 8 hours respectively. The permanent shift of the guinea pigs at the above two frequencies was at 4-8 kHz. As the duration of exposure were 4 hours, the threshold shift at 63 Hz was smaller than that at 4 kHz. But as the duration of exposure was 8 hours, the threshold shift at 63 Hz and 4 kHz was almost the same. No morphological change of the inner ear was observed in the guinea pigs exposed for 4 hours at the octave bands of noise centered at 63 Hz and 4 kHz, but ultrastructural abnormalities were noted. After the animals were exposed for 8 hours, morphological, ultrastructural changes in the inner ear were observed. The main pathologic changes were seen at the second turn of the cochlea. These changes in hearing physiology and pathology suggest that a high intensive low frequency noise can result in high frequency hearing loss and that the use of A-weighted levels of specific damage risk criteria for noise sources may be inappropriate.
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2102
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Qian J. Generalization of the Kolmogorov -5/3 law of turbulence. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1994; 50:611-613. [PMID: 9962009 DOI: 10.1103/physreve.50.611] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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2103
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Jin ZC, Qian J. [Inhibitory effects of fifteen kinds of Chinese herbal drugs, vegetables and chemicals on SOS response]. ZHONGHUA YU FANG YI XUE ZA ZHI [CHINESE JOURNAL OF PREVENTIVE MEDICINE] 1994; 28:147-50. [PMID: 7842869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Effects of 15 kinds of herbal drugs, vegetables and chemicals on lex-dependent sfi-SOS response were determined by micropersistent and/or pulse models induced by 4-Nitroquinoline-N-oxide (4NQO) and Mitomycin C (MMC) in Escherichia coli(E. coli) PQ37 and PQ35, respectively. Results showed the water extract of Rhizoma Polygonati (RP), Fructus Chebulae (FC), Radix Polygoni Multiflori (RPM), Fructus Ligustri Lucidi (FLL), Bulbus Fritillariae Thunbergii (BFT), shell of water chestnut with a pedicle, Chinese chives juice, and solutions of 5-Fluorouracil, Tannic acid and garlicin could inhibit SOS responses with a dose-response relationship and suggested the inhibitory effects took place both inside and outside E. coli cells. Water extract of FC, FLL, BFT, shell of water chestnut with a pedicle, Chinese chives juice and solution of 5-Fluorouracil and Tannic acid could intracellularly inhibit SOS responses induced by MMC in E. coli PQ35, and acetone extract of Grifola Frondosa (GF) could extracellularly inhibit SOS responses in E. coli PQ37 and intracellularly in PQ35 induced by 4NQO or MMC. Water extract of raw hawthorn. Radix Angelicae Duhuricae (RAD), Radix Ophiopogonis (RO), and 5-Fluorodeoxyuridine could extracellularly inhibit SOS responses induced by 4NQO in E coli PQ37. The possible mechanisms of intracellular inhibition and antidamage repair were discussed in the paper.
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2104
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Qian J, Bours V, Manischewitz J, Blackburn R, Siebenlist U, Golding H. Chemically selected subclones of the CEM cell line demonstrate resistance to HIV-1 infection resulting from a selective loss of NF-kappa B DNA binding proteins. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 1994; 152:4183-91. [PMID: 8144979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
To delineate cellular genes that are required for optimal HIV-1 infection, CEM cells were subjected to treatment with the chemical mutagen ethylmethanesulfonate (EMS) and subclones were selected based on their increased resistance to HIV-1 infection and reduced syncytium formation, despite relatively normal CD4 expression (20,000 to 25,000 receptors/cell). Two subclones with this phenotype demonstrated a diminished capacity of HIV-1 long terminal repeat-chloramphenicol acetyl transferase expression either after treatment with the protein kinase C activator PMA, or through Tat-mediated transactivation. In this study, we show that the cellular levels of the NF-kappa B DNA binding proteins (but not AP1 or SP1) are markedly reduced in these cell mutants both at the mRNA and protein levels, resulting in reduced nuclear localization of p50/p65 after PMA induction or treatment with the lymphokine TNF-alpha. Transient reconstitution with a plasmid expressing p50 resulted in partial recovery of PMA-inducible LTR-chloramphenicol acetyl transferase expression. These data suggest that, at least in the CEM T cell line, a selective reduction in the NF-kappa B DNA binding proteins is sufficient to curtail HIV-1 infection.
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2105
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Qian J, Bours V, Manischewitz J, Blackburn R, Siebenlist U, Golding H. Chemically selected subclones of the CEM cell line demonstrate resistance to HIV-1 infection resulting from a selective loss of NF-kappa B DNA binding proteins. THE JOURNAL OF IMMUNOLOGY 1994. [DOI: 10.4049/jimmunol.152.8.4183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
To delineate cellular genes that are required for optimal HIV-1 infection, CEM cells were subjected to treatment with the chemical mutagen ethylmethanesulfonate (EMS) and subclones were selected based on their increased resistance to HIV-1 infection and reduced syncytium formation, despite relatively normal CD4 expression (20,000 to 25,000 receptors/cell). Two subclones with this phenotype demonstrated a diminished capacity of HIV-1 long terminal repeat-chloramphenicol acetyl transferase expression either after treatment with the protein kinase C activator PMA, or through Tat-mediated transactivation. In this study, we show that the cellular levels of the NF-kappa B DNA binding proteins (but not AP1 or SP1) are markedly reduced in these cell mutants both at the mRNA and protein levels, resulting in reduced nuclear localization of p50/p65 after PMA induction or treatment with the lymphokine TNF-alpha. Transient reconstitution with a plasmid expressing p50 resulted in partial recovery of PMA-inducible LTR-chloramphenicol acetyl transferase expression. These data suggest that, at least in the CEM T cell line, a selective reduction in the NF-kappa B DNA binding proteins is sufficient to curtail HIV-1 infection.
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2106
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Qian J, Jin ZC. [Detection of SOS response inhibitor with E. coli GW1104 and GW1107 and its mechanism]. ZHONGHUA YU FANG YI XUE ZA ZHI [CHINESE JOURNAL OF PREVENTIVE MEDICINE] 1994; 28:84-7. [PMID: 7924653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
E. coli GW1104 and GW1107 are temperature-sensitive strains carrying a fusion gene umu:: Mud(Ap,lac) with genotypes recA441 (tif-1) and recA441 (tif-1),lexA (Def) (spr), respectively. SOS response can be produced spontaneously at 32 degrees C in E. coli GW1107, and induced at 42 degrees C in both E. coli GW1107 and GW1104. To detect SOS response inhibitor and to study its mechanism, a quick-test-system was established based on their genetic characteristics of the two strains. It was found some kinds of Chinese herbal medicine, vegetables, and chemicals could inhibit SOS response in the strains to different extent with varied mechanisms. Shell of water chestnut could inhibit temperature-induced SOS response at 42 degrees C in E. coli GW1104, and spontaneously-produced one at 32 degrees C in E.coli GW1107. Chinese chives can only inhibit temperature-induced SOS response in E. coli GW1104. It suggested the former's inhibition effect on SOS response occurred at lexA gene or on the pathway of SOS response before lexA gene, and so did the latter's on the pathway after lexA gene.
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2107
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Wang X, Qian J, Ko MS. Simple and robust screening of pooled yeast artificial chromosome libraries by the restriction enzyme digestion of polymerase chain reaction products. GENETIC ANALYSIS, TECHNIQUES AND APPLICATIONS 1994; 11:63-8. [PMID: 7803131 DOI: 10.1016/1050-3862(94)90052-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The polymerase chain reaction (PCR)-based method for screening pooled yeast artificial chromosome (YAC) libraries was modified by adding a step for the restriction enzyme digestion of the PCR products. This modification significantly increased the reliability of YAC screening and made it possible to identify YAC clones without a cumbersome verification step by colony hybridization and/or Southern blotting. Using this method, we assigned 39 mouse YAC clones to a mouse genetic map with 13 biallelic, polymorphic expressed sequence tags. This method provides a fast, reliable way to identify YAC clones with PCR-based sequence-tagged sites.
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2108
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Abstract
Reorientation of bacteriorhodopsin in the native purple membrane was studied by time-resolved linear dichroism spectroscopy (TRLD) over the millisecond time regime. The time responses observed in TRLD are distinctly different from the isotropic transient absorption (TA) at wavelengths in the range 550-590 nm, where the bacteriorhodopsin ground state absorbs. In contrast, the TA and TRLD responses have nearly identical time dependence at 410 and 690 nm, where the intermediates M and O, respectively, principally contribute. These results demonstrate ground-state bacteriorhodopsin reorientation triggered by the photocycle. The TRLD and TA data are analyzed to test models for reorientational motion. Rotational diffusion of ground-state bacteriorhodopsin cannot account for the details of the data. Rather, the results are shown to be consistent with a reversible reorientation of "spectator" (nonexcited) members of the bacteriorhodopsin trimer in the purple membrane in response to the photocycling member of the trimer. This response may be associated with cooperativity in the trimer.
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2109
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Qian J, Rodermel SR. Ribulose-1,5-bisphosphate carboxylase/oxygenase activase cDNAs from Nicotiana tabacum. PLANT PHYSIOLOGY 1993; 102:683-4. [PMID: 8108517 PMCID: PMC158830 DOI: 10.1104/pp.102.2.683] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
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2110
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Gardner CS, Kane TJ, Senft DC, Qian J, Papen GC. Simultaneous observations of sporadicE, Na, Fe, and Ca+layers at Urbana, Illinois: Three case studies. ACTA ACUST UNITED AC 1993. [DOI: 10.1029/93jd01477] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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2111
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Donnelly SG, Schmuttenmaer CA, Qian J, Farrar JM. Frequency- and time-resolved cluster photodissociation dynamics in Sr+(H2O) n , Sr+(NH3) n and Sr+(CH3OH) n. ACTA ACUST UNITED AC 1993. [DOI: 10.1039/ft9938901457] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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2112
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Qian J, Polymeropoulos C, Ulisse R. Liquid jet evolution from a gas chromatographic injector. J Chromatogr A 1992. [DOI: 10.1016/0021-9673(92)80169-u] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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2113
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Hillman K, Qian J, Siegel JN, Roderiquez G, Blackburn R, Manischewitz J, Norcross M, Golding H. Reduced susceptibility to HIV-1 infection of ethyl-methanesulfonate-treated CEM subclones correlates with a blockade in their protein kinase C signaling pathway. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 1992; 148:3991-8. [PMID: 1351090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/25/2023]
Abstract
We have described the isolation of chemically induced CEM subclones that express CD4 receptors and bind soluble gp120, yet show a markedly reduced susceptibility to infection with HIV-1. Two subclones were found to have an abnormal response to the protein kinase C (PKC) activator PMA. PMA treatment induced CD3 and CD25 (IL-2R) receptors on the parental line and on other ethyl-methanesulfonate-derived subclones, but not on these two mutants. Direct assays of PKC activity were conducted. Total cellular PKC enzymatic activity was found to be normal in these subclones. PMA-induced CD4 down-modulation occurred normally. In addition, activation of c-raf kinase was normal. Since HIV-1 long terminal repeat contains two functional nuclear factor kB (NF-kB) regulatory elements, we studied the ability of PMA to induce NF-kB binding activity by different assays. Chloramphenicol acetyl transferase (CAT) assays using the HIV-1 (-139)long terminal repeat-CAT construct showed no PMA induction of CAT activity in these subclones (unlike the parental line and other subclones). Okadaic acid, an inhibitor of phosphatases 1 and 2A, did not overcome the defect in these subclones. Gel retardation assays, using a 32P-probe containing the HIV-1 NF-kB probe and nuclear extracts from PMA-treated cells, showed significantly reduced induction of nuclear NF-kB binding proteins in these two subclones compared with wild type CEM and a control subclone. Deoxycholate treatment of cytoplasmic extracts from these subclones released much reduced NF-kB binding proteins from their cytoplasmic pools. Thus, reduced levels of PKC-induced nuclear NF-kB activity in two T cell subclones did not affect their normal cell growth, but correlated with a pronounced reduction in their susceptibility to HIV-1 infection.
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2114
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Hillman K, Qian J, Siegel JN, Roderiquez G, Blackburn R, Manischewitz J, Norcross M, Golding H. Reduced susceptibility to HIV-1 infection of ethyl-methanesulfonate-treated CEM subclones correlates with a blockade in their protein kinase C signaling pathway. THE JOURNAL OF IMMUNOLOGY 1992. [DOI: 10.4049/jimmunol.148.12.3991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
We have described the isolation of chemically induced CEM subclones that express CD4 receptors and bind soluble gp120, yet show a markedly reduced susceptibility to infection with HIV-1. Two subclones were found to have an abnormal response to the protein kinase C (PKC) activator PMA. PMA treatment induced CD3 and CD25 (IL-2R) receptors on the parental line and on other ethyl-methanesulfonate-derived subclones, but not on these two mutants. Direct assays of PKC activity were conducted. Total cellular PKC enzymatic activity was found to be normal in these subclones. PMA-induced CD4 down-modulation occurred normally. In addition, activation of c-raf kinase was normal. Since HIV-1 long terminal repeat contains two functional nuclear factor kB (NF-kB) regulatory elements, we studied the ability of PMA to induce NF-kB binding activity by different assays. Chloramphenicol acetyl transferase (CAT) assays using the HIV-1 (-139)long terminal repeat-CAT construct showed no PMA induction of CAT activity in these subclones (unlike the parental line and other subclones). Okadaic acid, an inhibitor of phosphatases 1 and 2A, did not overcome the defect in these subclones. Gel retardation assays, using a 32P-probe containing the HIV-1 NF-kB probe and nuclear extracts from PMA-treated cells, showed significantly reduced induction of nuclear NF-kB binding proteins in these two subclones compared with wild type CEM and a control subclone. Deoxycholate treatment of cytoplasmic extracts from these subclones released much reduced NF-kB binding proteins from their cytoplasmic pools. Thus, reduced levels of PKC-induced nuclear NF-kB activity in two T cell subclones did not affect their normal cell growth, but correlated with a pronounced reduction in their susceptibility to HIV-1 infection.
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2115
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Qian J. [Catheter closure of patent ductus arteriosus without thoracotomy]. ZHONGHUA XIN XUE GUAN BING ZA ZHI 1992; 20:167-8, 196. [PMID: 1289028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Transcatheter plugging of patent ductus arteriosus with modified Porstmann's method was performed in children of school age and adults (130 cases) in recent 10 years. We devised a set of instrument, self-made plastic Ivalon for tailoring the plugs, developed the technique of retrograde aortic angiography to measure the diameter of the ductus, and determined the criteria of definite lodgement of the plug. 3 cases failed because their femoral arteries were too small to have the catheter sheath introduced. The other 3 cases developed thrombosis of the femoral arteries after the procedure, and the thrombi were removed by surgery.
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2116
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Jin ZC, Qian J. Plasmid pSK1002-mediated mutator effect and SOS response and SOS mutagenesis of 2,5-dichloronitrobenzol in Salmonella typhimurium. Mutat Res 1991; 264:1-5. [PMID: 1881412 DOI: 10.1016/0165-7992(91)90038-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The plasmid pSK1002 (umuC'-'lacZ) could increase the number of revertants induced by methyl methanesulfonate (MMS) and 4-nitroquinoline-N-oxide (4NQO) in Salmonella typhimurium TA 1535 (his-). The values induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) were not different irrespective of the presence or absence of plasmid. However, the plasmid pKM101-mediated mutagenesis-enhancing effect was much greater than that mediated by pSK1002 as induced by the 3 mutagens mentioned above. Moreover, the plasmid pSK1002 could induced umu-mediated SOS response in the presence of any of these 3 mutagens or of mitomycin C, and a dose-response relationship was evident. It shows that pSK1002 (umuC'-'lacZ) has a dual biological effect, namely a mutator effect and the effect of inducing the SOS response. Besides, this study has proved SOS mutagenesis of 2,5-dichloronitrobenzol (2,5-DCNB) because of the dual indicator nature of pSK1002. Therefore, it is probable that pSK1002 could be further developed and applied in studying the relation between the SOS response and mutagenesis and in identifying environmental SOS mutagens.
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2117
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Jin ZC, Qian J. [Plasmid pSK1002-mediated mutator effect and SOS response in Salmonella typhimurium and its use for detection of mutagens]. ZHONGHUA YU FANG YI XUE ZA ZHI [CHINESE JOURNAL OF PREVENTIVE MEDICINE] 1991; 25:292-5. [PMID: 1773674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The plasmid pSK1002 carrying the fused gene umuC'-'lacZ could increase the number of revertants induced by methyl methanesulfonate (MMS) and 4-nitroquinoline-1-oxide (4NQO) in S. typhimurium LT2 TA 1535(his-). Maximum revertants were 4.35 and 3.96 times that of the controls without the plasmid. The values induced by N-methyl-N'-nitrosoquanidine (MN-NG) were about the same with or without plasmid. However, the plasmid pKM101-mediated mutagenesis-enhancing effect was much greater than that through the mediation of pSK1002 as induced by the three mutagens mentioned above. Moreover, the plasmid pSK1002 could induce umu-mediated SOS response in the presence, of either mutagen stated above and mitomycin C(MMC). Maximum levels of beta-galactosidase (beta-gal) activity induced by four mutagens respectively were 4.56, 7.14, 4.94, and 3.42 times that of the controls, and a dose-response relationship was evident. The sensitivity of SOS response was superior to mutagenesis-enhancing effect. It showed that pSK1002 (umuC'-'lacZ) had a dual biological effect, namely, mutator effect and the effect of inducing SOS response. Besides, this study has proved SOS mutagenesis of 2,5-dichloronitrobenzol (2,5-DCNB). Because of the dual indicator nature of pSK1002, it is probable that pSK1002 would be further developed and applied in studying the relation between SOS response and mutagenesis, and monitoring environmental SOS mutagens.
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2118
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Wu DY, Ugozzoli L, Pal BK, Qian J, Wallace RB. The effect of temperature and oligonucleotide primer length on the specificity and efficiency of amplification by the polymerase chain reaction. DNA Cell Biol 1991; 10:233-8. [PMID: 2012681 DOI: 10.1089/dna.1991.10.233] [Citation(s) in RCA: 111] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The polymerase chain reaction (PCR) is most effectively performed using a thermostable DNA polymerase such as that isolated from Thermus aquaticus. Since temperature and oligonucleotide length are known to control the specificity of oligonucleotide hybridization, we have investigated the effect of oligonucleotide length, base composition, and the annealing temperature on the specificity and efficiency of amplification by the PCR. Generally, the specificity of PCR is controlled by the length of the oligonucleotide and/or the temperature of annealing of the primer to the template. An empirical relationship between oligonucleotide length and ability to support amplification was determined. This relationship allows for the design of specific oligonucleotide primers. A model is proposed which helps explain the observed dependence of PCR on annealing temperature and length of the primer.
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2119
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Wan CZ, Qian J, Johnson CK. Conformational motion in bacteriorhodopsin: the K to L transition. Biochemistry 1991; 30:394-400. [PMID: 1988038 DOI: 10.1021/bi00216a013] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
By comparison of the time dependence of linear dichroism and transient absorption in light-adapted bacteriorhodopsin over the first 10 microseconds following excitation, conformational motion in the protein has been detected. Time-resolved linear dichroism and transient absorption scans are reported for several wavelengths that probe the K610 and L550 intermediates in the bacteriorhodopsin photocycle. The transient absorption scans are insensitive to conformational motion and yield the lifetimes of the K610 and L550 intermediates. In contrast, the time-resolved linear dichroism scans demonstrate orientational motion of the chromophore with a 1.7-microsecond rotational time. The wavelength dependence of the least-squares fitting parameters establishes that this motion is associated with L550. This motion is discussed in relation to a protein conformational change in the course of the bacteriorhodopsin photocycle. No evidence is observed for orientational motion on the time scale of the L550----M410 transition.
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2120
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Forrest GL, Qian J, Ma JX, Kaplan WD, Akman S, Doroshow J, Chen SA. Rat liver NAD(P)H:quinone oxidoreductase: cDNA expression and site-directed mutagenesis. Biochem Biophys Res Commun 1990; 169:1087-93. [PMID: 2141979 DOI: 10.1016/0006-291x(90)92006-l] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Rat liver NAD(P)H:quinone oxidoreductase cDNA was cloned and expressed in a eukaryotic cell expression plasmid containing a cytomegalovirus (CMV) promoter. Transient expression of enzyme activity and RNA transcription were measured in COS7 cells. The expressed quinone reductase has kinetic properties similar to the rat liver enzyme and is inhibited by dicourmarol, a known inhibitor of NAD(P)H:quinone oxidoreductase. Site-directed mutagenesis experiments carried out using this expression system revealed possible regions involved in NAD(P)H binding.
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2121
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Wang J, Chen C, Qian J, Tao H. The pharmacological studies of gecko. J TRADIT CHIN MED 1990; 10:146-51. [PMID: 2392000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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2122
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Qian J, Barlow JS, Beddoes MP. A simplified arithmetic detector for EEG sharp transients--preliminary results. IEEE Trans Biomed Eng 1988; 35:11-8. [PMID: 3338807 DOI: 10.1109/10.1331] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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2123
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Qian J, Hickey WF, Angeletti RH. Neuroendocrine cells in intestinal lamina propria. Detection with antibodies to chromogranin A. J Neuroimmunol 1988; 17:159-65. [PMID: 3257217 DOI: 10.1016/0165-5728(88)90023-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
This study details immunohistochemical experiments showing the location of chromogranin A-containing cells within the lamina propria of rat and human gut. The presence of this marker confirms the presence of neuroendocrine type cells in the lamina propria.
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2124
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Mohan S, Qian J, Rao NL. Efficient point-to-point and point-to-multipoint selective-repeat ARQ schemes with multiple retransmissions: a throughput analysis. ACM SIGCOMM COMPUTER COMMUNICATION REVIEW 1987. [DOI: 10.1145/55483.55489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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2125
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Fung YK, Murphree AL, T'Ang A, Qian J, Hinrichs SH, Benedict WF. Structural evidence for the authenticity of the human retinoblastoma gene. Science 1987; 236:1657-61. [PMID: 2885916 DOI: 10.1126/science.2885916] [Citation(s) in RCA: 534] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The retinoblastoma (Rb) gene is the prototype for a class of recessive human cancer genes in which loss of activity of both normal alleles is thought to be associated with tumorigenesis. Sixteen of 40 retinoblastomas examined with a complementary DNA probe shown to be the Rb gene had identifiable structural changes of the Rb gene including in some cases homozygous internal deletions with corresponding truncated transcripts. An osteosarcoma also had a homozygous internal deletion with a truncated transcript. In addition, possible hot spots for deletion were identified within the Rb genomic locus. Among those tumors with no identifiable structural changes there was either absence of an Rb transcript or abnormal expression of the Rb transcript. Comparison of the structural changes in the tumor cells and fibroblasts of certain patients provided support for Knudson's two-hit hypothesis for the development of retinoblastoma at the molecular level. The ability to detect germline structural deletions in fibroblasts from some patients with bilateral retinoblastoma also indicates that the isolated gene is useful for diagnostic purposes.
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