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Chang WC, Hsieh YY, Cheng TC, Chang CC, Tsai HD, Lee MS. Effect of methylglyoxal on mouse embryogenesis. CHANG GUNG MEDICAL JOURNAL 2001; 24:251-7. [PMID: 11413883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
BACKGROUND Methylglyoxal (MG), a highly active and mutagenetic compound, has been found widely in a variety of foods and beverages. We investigated the effect of MG on mouse embryo development in-vitro. METHODS Two-cell mouse embryos were divided into six groups according to the MG concentration in the culture medium: Group 1 (control group). 0 mM; Group 2, 10(-4) mM; Group 3, 10(-3) mM; Group 4, 10(-2) mM; Group 5, 10(-1) mM; Group 6, 1 mM. Embryo development and cleavage were compared every day for 5 days. RESULTS The percentages of embryos reaching blastocyst/hatching stages were as follows: Group 1, 66.8%/34.2%; Group 2, 67.9%/38.7%; Group 3, 56.2%/31.5%; Group 4, 39.4%/14.1%; Group 5, 11.4%/10.2%; Group 6, 0%/0%. Higher MG concentrations (> or = 10(-2) mM) were associated with morphological aberrations and blocked development of embryos. CONCLUSION The cutoff value of MG concentration on the mouse embryo development in-vitro is 10(-2) mM. An increased risk of embryotoxicity occurs with MG concentrations > or = 10(-2) mM in vitro. There were no significant effects on the growth rate at MG concentrations of 10(-3) and 10(-4) mM.
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Hill CM, Li WS, Cheng TC, DeFrank JJ, Raushel FM. Stereochemical specificity of organophosphorus acid anhydrolase toward p-nitrophenyl analogs of soman and sarin. Bioorg Chem 2001; 29:27-35. [PMID: 11300693 DOI: 10.1006/bioo.2000.1189] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Organophosphorus acid anhydrolase (OPAA) catalyzes the hydrolysis of p-nitrophenyl analogs of the organophosphonate nerve agents, sarin and soman. The enzyme is stereoselective toward the chiral phosphorus center by displaying a preference for the R(P)-configuration of these analogs. OPAA also exhibits an additional preference for the stereochemical configuration at the chiral carbon center of the soman analog. The preferred configuration of the chiral carbon center is dependent upon the configuration at the phosphorus center. The enzyme displays a two- to four-fold preference for the R(P)-enantiomer of the sarin analog. The k(cat)/K(m) of the R(P)-enantiomer is 250 M(-1) s(-1), while that of the S(P)-enantiomer is 110 M(-1) s(-1). The order of preference for the stereoisomers of the soman analog is R(P)S(C) > R(P)R(C) > S(P)R(C) > S(P)S(C). The k(cat)/K(m) values are 36,300 M(-1)s(-1), 1250 M(-1) s(-1), 80 M(-1) s(-1) and 5 M(-1) s(-1), respectively. The R(P)S(C)-isomer of the soman analog is therefore preferred by a factor of 7000 over the S(P)S(C)-isomer.
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Petrikovics I, Cheng TC, Papahadjopoulos D, Hong K, Yin R, DeFrank JJ, Jaing J, Song ZH, McGuinn WD, Sylvester D, Pei L, Madec J, Tamulinas C, Jaszberenyi JC, Barcza T, Way JL. Long circulating liposomes encapsulating organophosphorus acid anhydrolase in diisopropylfluorophosphate antagonism. Toxicol Sci 2000; 57:16-21. [PMID: 10966507 DOI: 10.1093/toxsci/57.1.16] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
These studies are focused on antagonizing organophosphorous (OP) intoxications by a new conceptual approach using recombinant enzymes encapsulated within sterically stabilized liposomes to enhance diisopropylfluorophosphate (DFP) degradation. The OP hydrolyzing enzyme, organophosphorous acid anhydrolase (OPAA), encapsulated within the liposomes, was employed either alone or in combination with pralidoxime (2-PAM) and/or atropine. The recombinant OPAA enzyme, from the ALTEROMONAS: strain JD6, has high substrate specificity toward a wide range of OP compounds, e.g., DFP, soman, and sarin. The rate of DFP hydrolysis by liposomes containing OPAA (SL)* was measured by determining the changes in fluoride-ion concentration using a fluoride ion-selective electrode. This enzyme carrier system serves as a biodegradable protective environment for the OP-metabolizing enzyme (OPAA), resulting in an enhanced antidotal protection against the lethal effects of DFP. Free OPAA alone showed some antidotal protection; however, the protection with 2-PAM and/or atropine was greatly enhanced when combined with (SL)*.
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Hill CM, Wu F, Cheng TC, DeFrank JJ, Raushel FM. Substrate and stereochemical specificity of the organophosphorus acid anhydrolase from Alteromonas sp. JD6.5 toward p-nitrophenyl phosphotriesters. Bioorg Med Chem Lett 2000; 10:1285-8. [PMID: 10866401 DOI: 10.1016/s0960-894x(00)00213-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The enzyme OPAA hydrolyzes p-nitrophenyl phosphotriesters bearing substituents at the phosphorus center ranging in size from methyl to phenyl. The enzyme exhibits stereoselectivity toward the hydrolysis of chiral substrates with a preference for the Sp enantiomer.
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Petrikovics I, McGuinn WD, Sylvester D, Yuzapavik P, Jiang J, Way JL, Papahadjopoulos D, Hong K, Yin R, Cheng TC, DeFrank JJ. In vitro studies on sterically stabilized liposomes (SL) as enzyme carriers in organophosphorus (OP) antagonism. Drug Deliv 2000; 7:83-9. [PMID: 10892408 DOI: 10.1080/107175400266641] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022] Open
Abstract
This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine.
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Cheng TC, Ramakrishnan V, Chan SI. Purification and characterization of a cobalt-activated carboxypeptidase from the hyperthermophilic archaeon Pyrococcus furiosus. Protein Sci 1999; 8:2474-86. [PMID: 10595552 PMCID: PMC2144183 DOI: 10.1110/ps.8.11.2474] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
A novel metallocarboxypeptidase (PfuCP) has been purified to homogeneity from the hyperthermophilic archaeon, Pyrococcus furiosus, with its intended use in C-terminal ladder sequencing of proteins and peptides at elevated temperatures. PfuCP was purified in its inactive state by the addition of ethylenediaminetetraacetic acid (EDTA) and dithiothreitol (DTT) to purification buffers, and the activity was restored by the addition of divalent cobalt (K, = 24 +/- 4 microM at 80 degrees C). The serine protease inhibitor phenylmethylsulfonyl fluoride (PMSF) had no effect on the activity. The molecular mass of monomeric PfuCP is 59 kDa as determined by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and 58 kDa by SDS-PAGE analysis. In solution, PfuCP exists as a homodimer of approximately 128 kDa as determined by gel filtration chromatography. The activity of PfuCP exhibits a temperature optimum exceeding 90 degrees C under ambient pressure, and a narrow pH optimum of 6.2-6.6. Addition of Co2+ to the apoPfuCP at room temperature does not alter its far-UV circular dichroism (CD) or its intrinsic fluorescence spectrum. Even when the CoPfuCP is heated to 80 degrees C, its far-UV CD shows a minimal change in the global conformation and the intrinsic fluorescence of aromatic residues shows only a partial quenching. Changes in the intrinsic fluorescence appear essentially reversible with temperature. Finally, the far-UV CD and intrinsic fluorescence data suggest that the overall structure of the holoenzyme is extremely thermostable. However, the activities of both the apo and holo enzyme exhibit a similar second-order decay over time, with 50% activity remaining after approximately 40 min at 80 degrees C. The N-blocked synthetic dipeptide, N-carbobenzoxy-Ala-Arg (ZAR), was used in the purification assay. The kinetic parameters at 80 degrees C with 0.4 mM CoCl2 were: Km, 0.9 +/- 0.1 mM; Vmax, 2,300 +/- 70 U mg(-1); and turn over number, 600 +/- 20 s(-1). Activity against other ZAX substrates (X = V, L, I, M, W, Y, F, N, A, S, H, K) revealed a broad specificity for neutral, aromatic, polar, and basic C-terminal residues. This broad specificity was confirmed by the C-terminal ladder sequencing of several synthetic and natural peptides, including porcine N-acetyl-renin substrate, for which we have observed (by MALDI-TOF MS) stepwise hydrolysis by PfuCP of up to seven residues from the C-terminus: Ac-Asp-Arg-Val-Tyr-Ile-His-Pro-Phe-His-Leu-Leu-Val-Tyr-Ser.
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Huang CC, Cheng TC, Chang HH, Chang CC, Chen CI, Liu J, Lee MS. Birth after the injection of sperm and the cytoplasm of tripronucleate zygotes into metaphase II oocytes in patients with repeated implantation failure after assisted fertilization procedures. Fertil Steril 1999; 72:702-6. [PMID: 10521114 DOI: 10.1016/s0015-0282(99)00309-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To assess the technique of injecting a single sperm and cytoplasm obtained from tripronucleate zygotes into metaphase II oocytes for the treatment of patients with repeated implantation failure after intracytoplasmic sperm injection or IVF. DESIGN Clinical study. SETTING Private infertility clinic. PATIENT(S) Patients with repeated implantation failure after intracytoplasmic sperm injection or IVF. INTERVENTION(S) The metaphase II oocytes of recipients were injected with their husbands' spermatozoa and cytoplasm aspirated from the tripronucleate zygotes of donors. MAIN OUTCOME MEASURE(S) Fertilization after cytoplasm and sperm injection, embryo development, and successful pregnancy. RESULT(S) In total, 62 metaphase II oocytes from nine recipients were injected. Of the 62 injected oocytes, 3 (5%) degenerated and 43 (69%) had two pronuclei 18 hours after injection. Thirty-nine oocytes with two pronuclei cleaved to the two-cell to six-cell stage after another 24 hours of culture. All cleaved embryos were transferred into the uteruses of recipients. Four clinical pregnancies occurred in four recipients. No abnormal chromosomes were observed after amniocentesis and karyotyping in all pregnancies. Five healthy infants were born. CONCLUSION(S) Injection of the cytoplasm of tripronucleate zygotes may enhance the clinical pregnancy rate in patients with repeated implantation failure after intracytoplasmic sperm injection or IVF.
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Cheng TC, DeFrank JJ, Rastogi VK. Alteromonas prolidase for organophosphorus G-agent decontamination. Chem Biol Interact 1999; 119-120:455-62. [PMID: 10421483 DOI: 10.1016/s0009-2797(99)00058-7] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Enzymes catalyzing the hydrolysis of highly toxic organophosphorus compounds (OPs) are classified as organophosphorus acid anhydrolases (OPAA; EC 3.1.8.2). Recently, the genes encoding OPAA from two species of Alteromonas were cloned and sequenced. Sequence and biochemical analyses of the cloned genes and enzymes have established Alteromonas OPAAs to be prolidases (E.C. 3.4.13.9), a type of dipeptidase hydrolyzing dipeptides with a prolyl residue in the carboxyl-terminal position (X-Pro). Alteromonas prolidases hydrolyze a broad range of G-type chemical warfare (CW) nerve agents. Efforts to over-produce a prolidase from A. sp.JD6.5 with the goal of developing strategies for long-term storage and decontamination have been successfully achieved. Large-scale production of this G-agent degrading enzyme is now feasible with the availability of an over-producing recombinant cell line. Use of this enzyme for development of a safe and non-corrosive decontamination system is discussed.
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Cheng TC, Rastogi VK, DeFrank JJ, Sawiris GP. G-type nerve agent decontamination by Alteromonas prolidase. Ann N Y Acad Sci 1998; 864:253-8. [PMID: 9928098 DOI: 10.1111/j.1749-6632.1998.tb10316.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Rastogi VK, DeFrank JJ, Cheng TC, Wild JR. Enzymatic hydrolysis of Russian-VX by organophosphorus hydrolase. Biochem Biophys Res Commun 1997; 241:294-6. [PMID: 9425265 DOI: 10.1006/bbrc.1997.7569] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The Russian-VX (R-VX) is the principle V-type nerve agent in the chemical warfare (CW) arsenal of the Former Soviet Union. We here report the enzymatic hydrolysis of the P-S bond of Russian-VX by organophosphorus hydrolase (OPH) from Pseudomonas diminuta. While the Michaelis constant, K(m) for R-VX (474 microM), was similar to that for VX (434 microM), the Vmax for R-VX (2.1 mumoles/mg/min) was about four-fold higher compared to that for VX (0.56 mumoles/mg/min). A 50% inhibition in the rate of the enzymatic hydrolysis of R-VX was observed in the presence of 0.5% ethanol, isoamyl-alcohol, or isopropanol. The presence of acetonitrile, diethylene glycol, or methanol had marginal effects. These results comprise the first demonstration of enzymatic detoxification of R-VX.
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Chang CP, Liu RS, Yu SM, Wynchank S, Chu LS, Shiau HY, Cheng TC. Clinical evaluation of the bone marrow imaging agent 99Tcm-phytate in the detection of bone metastases. Nucl Med Commun 1996; 17:1030-4. [PMID: 9004298 DOI: 10.1097/00006231-199612000-00005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The aims of this study were to assess whether 99Tcm-phytate can detect metastatic skeletal lesions, and to compare it with 99Tcm-methylene diphosphonate (99Tcm-MDP) and 99Tcm-labelled human serum albumin nanocolloids (99Tcm-NC). Twenty-four patients with multiple bony metastases, investigated by 99Tcm-MDP whole-body scintigraphy, underwent 99Tcm-phytate bone marrow imaging. A separate bone marrow scintigram with 99Tcm-NC was performed in 20 of the patients. All of the metastatic lesions detected on the 99Tcm-phytate scintigrams exhibited photon-abundant foci only. Most of the 99Tcm-phytate scintigrams detected fewer metastatic lesions than the corresponding bone scintigrams. Visual comparison of the 99Tcm-NC images showed that 13 of 20 99Tcm-NC images were superior to the 99Tcm-phytate images in the detection of metastatic involvement of the skeleton. Thus 99Tcm-phytate should not be used as a bone marrow imaging agent for the detection of skeletal metastases.
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Wang CJ, Cheng TC, Liu JY, Chou FP, Kuo ML, Lin JK. Inhibition of protein kinase C and proto-oncogene expression by crocetin in NIH/3T3 cells. Mol Carcinog 1996; 17:235-40. [PMID: 8989917 DOI: 10.1002/(sici)1098-2744(199612)17:4<235::aid-mc7>3.0.co;2-c] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Crocetin, a carotenoid isolated from the seeds of Gardenia jasminoides, was found to be a potent inhibitor of tumor promotion induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in mouse skin. When mouse fibroblast NIH/3T3 cells were treated with TPA alone, protein kinase C (PKC) translocated from the cytosolic fraction to the particulate fraction. Pretreatment with 60 and 120 microM crocetin for 15 min inhibited the TPA-induced PKC activity in the particulate fraction by 50% and 66%, respectively, but did not affect the level of PKC protein. Crocetin also reduced the level of TPA-stimulated phosphorylation of cellular proteins. Cells pretreated with crocetin (120 microM) had 55% less PKC [3H]phorbol dibutyrate-binding capacity. Suppression of TPA (100 ng/mL)-induced c-jun and c-fos gene expression was also observed in the mouse fibroblast cells pretreated with crocetin (30, 60, and 120 microM). Our results provided a basis for understanding the inhibitory effect of crocetin on TPA-mediated tumor promotion.
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Benton HP, Cheng TC, MacDonald MH. Use of adverse conditions to stimulate a cellular stress response by equine articular chondrocytes. Am J Vet Res 1996; 57:860-5. [PMID: 8725814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE To determine the response of equine articular cartilage cells to heat and calcium stresses. DESIGN Analysis of newly synthesized, [35S]methionine-labeled proteins after treatment of isolated primary equine chondrocytes. PROCEDURE Primary cultures of equine articular chondrocytes were incubated at temperatures ranging from 37 to 42 C for heat stress experiments or incubated in the presence or absence of the intracellular calcium pump inhibitor, thapsigargin, for calcium stress experiments. Patterns of new protein synthesis were determined by incubating with [35S]methionine followed by separation of proteins by use of one- or two-dimensional gel electrophoresis and visualization of labeled proteins by use of fluorography. RESULTS Equine chondrocytes cultured at temperature of 42 C had increased synthesis of specific proteins, compared with the profile of protein synthesis in control chondrocytes cultured at 37 C. These changes were characteristic of the heat shock stress response described in a number of other mammalian cell-types. Equine chondrocytes cultured in the presence of thapsigargin also had increased synthesis of specific proteins. Two-dimensional gel electrophoresis of these newly synthesized proteins revealed the changes to be consistent with the induction of the glucose-regulated protein family of stress proteins. CONCLUSIONS Changes in the pattern of new protein synthesis can be induced in differentiated equine articular chondrocytes by heat shock or calcium stress. These responses are characteristic of a widely described mammalian stress response that has been postulated to be involved in cellular protective mechanisms. The ability of equine chondrocytes to mount a robust stress response may be important in the processes of tissue damage and recovery in articular joints of horses.
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Cheng TC, Harvey SP, Chen GL. Cloning and expression of a gene encoding a bacterial enzyme for decontamination of organophosphorus nerve agents and nucleotide sequence of the enzyme. Appl Environ Microbiol 1996; 62:1636-41. [PMID: 8633861 PMCID: PMC167937 DOI: 10.1128/aem.62.5.1636-1641.1996] [Citation(s) in RCA: 104] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Organophosphorus acid (OPA) anhydrolase enzymes have been found in a wide variety of prokaryotic and eukaryotic organisms. Interest in these enzymes has been prompted by their ability to catalyze the hydrolysis of toxic organophosphorus cholinesterase-inhibiting compounds, including pesticides and chemical nerve agents. The natural substrates for these enzymes are unknown. The gene (opaA) which encodes an OPA anhydrolase (OPAA-2) was isolated from an Alteromonas sp. strain JD6.5 EcoRI-lambda ZAPII chromosomal library expressed in Escherichia coli and identified by immunodetection with anti-OPAA-2 serum. OPA anhydrolase activity expressed by the immunopositive recombinant clones was demonstrated by using diisopropylfluorophosphate (DFP) as a substrate. A comparison of the recombinant enzyme with native, purified OPAA-2 showed they had the same apparent molecular mass (60 kDa), antigenic properties, and enzyme activity against DFP and the chemical nerve agents sarin, soman, and O-cyclohexyl methylphosphonofluoridate. The gene expressing this activity was found in a 1.74-kb PstI-HindIII fragment of the original 6.1-kb EcoRI DNA insert. The nucleotide sequence of this PstI-HindIII fragment revealed an open reading frame of 1,551 nucleotides, coding for a protein of 517 amino acid residues. Amino acid sequence comparison of OPAA-2 with the protein database showed that OPAA-2 is similar to a 647-amino-acid sequence produced by an open reading frame which appears to be the E. coli pepQ gene. Further comparison of OPAA-2, the E. coli PepQ protein sequence, E. coli aminopeptidase P, and human prolidase showed regions of different degrees of similarity or functionally conserved amino acid substitutions. These findings, along with preliminary data confirming the presence of prolidase activity expressed by OPAA-2, suggest that the OPAA-2 enzyme may, in nature, be used in peptide metabolism.
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Yu H, Bruno JG, Cheng TC, Calomiris JJ, Goode MT, Gatto-Menking DL. A comparative study of PCR product detection and quantitation by electro-chemiluminescence and fluorescence. JOURNAL OF BIOLUMINESCENCE AND CHEMILUMINESCENCE 1995; 10:239-45. [PMID: 8533605 DOI: 10.1002/bio.1170100407] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Amplification and detection of target DNA sequences are made possible in a polymerase chain reaction (PCR) by using a mixture of biotinylated and ruthenium(II) trisbipyridal (Ru(bpy)3(2+))-end-labelled primers. In this way, biotin for capture and Ru(bpy)3(2+) for detection are directly incorporated into the PCR product obviating subsequent probe hybridization. PCR of a bacterial DNA template from Alteromonas species strain JD6.5 using a cocktail of biotin- and Ru(bpy)3(2+)-labelled primers amplified a 1 kilobase region. Serial dilution of PCR product followed by magnetic separation with Streptavidin (SA)-coated magnetic beads and an electrochemiluminescence (ECL) assay using the semi-automated QPCR System 5000 demonstrated sensitive (pg range) DNA detection. ECL assay of probe hybridization to a human immunodeficiency virus (HIV) sequence also produced pg level sensitivity. Quantitative DNA determination by ECL assay correlated well with visual detection of DNA in electrophoretic gels. However, DNA detection by ECL assay was 10 to 100 times more sensitive than conventional ethidium bromide staining. The combination of DNA-based magnetic separation with ECL assay provides a very sensitive and rapid method of quantitating DNA which, owing to its rapid and facile nature, may have many applications in the research, environmental monitoring, industrial and clinical fields.
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Cheng TC, Tsai TC, Lin GJ. Successful medical treatment for staphylococcal vertebral osteomyelitis complicated by spinal epidural abscess, psoas abscess and meningitis: a case report. GAOXIONG YI XUE KE XUE ZA ZHI = THE KAOHSIUNG JOURNAL OF MEDICAL SCIENCES 1995; 11:295-9. [PMID: 7602668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A 42 year-old farmer was transferred to our hospital for recently exaggerated lower back pain. Neurological examination revealed an L4 radiculopathy on the right side. Meningitis developed after admission. MRI showed L4-5 osteomyelitis and discitis with contiguous spinal epidural abscess and right psoas abscess. Blood culture and CSF culture both grew Staphylococcus aureus. Because the patient refused to receive a drainage procedure, we gave him antibiotics which resulted in a favorable outcome.
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Cheng TC, Tseng BS, Merlie JP, Klein WH, Olson EN. Activation of the myogenin promoter during mouse embryogenesis in the absence of positive autoregulation. Proc Natl Acad Sci U S A 1995; 92:561-5. [PMID: 7831329 PMCID: PMC42781 DOI: 10.1073/pnas.92.2.561] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Myogenin, a member of the MyoD family of helix-loop-helix proteins, can induce myogenesis in a wide range of cell types. In addition to activating muscle structural genes, members of the MyoD family can autoactivate their own and cross-activate one another's expression in transfected cells. This has led to the hypothesis that autoregulatory loops among these factors provide a mechanism for amplifying and maintaining the muscle-specific gene expression program in vivo. Here, we make use of myogenin-null mice to directly test this hypothesis. To investigate whether the myogenin protein autoregulates the myogenin gene during embryogenesis, we introduced a myogenin-lacZ transgene into mice harboring a null mutation at the myogenin locus. Despite a severe deficiency of skeletal muscle in myogenin-null neonates, the myogenin-lacZ transgene was expressed normally in myogenic cells throughout embryogenesis. These results show that myogenin is not required for regulation of the myogenin gene and argue against the existence of a myogenin autoregulatory loop in the embryo.
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Cheng TC, Benton HP. The intracellular Ca(2+)-pump inhibitors thapsigargin and cyclopiazonic acid induce stress proteins in mammalian chondrocytes. Biochem J 1994; 301 ( Pt 2):563-8. [PMID: 8043004 PMCID: PMC1137118 DOI: 10.1042/bj3010563] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Primary cultures of mammalian articular chondrocytes respond to treatment with the intracellular Ca(2+)-pump inhibitors thapsigargin (TG) and cyclopiazonic acid by specific changes in protein synthesis consistent with a stress response. Two-dimensional gel electrophoresis of newly synthesized proteins confirmed that the response was consistent with the induction of glucose-regulated proteins. The effects of low-dose TG (10 nM), measured by changes in [35S]methionine labelling of newly synthesized proteins, can first be observed by 10 h and are maximal by 24 h. The pattern of changes induced by TG is shared with cyclopiazonic acid, but effects of both perturbants differ significantly from changes induced by heat shock. Upon removal of TG, normal protein synthesis is restored by 48 h. Immunoblots showed increased concentrations of the stress proteins HSP90, HSP72/73 and HSP60 in chondrocytes treated with TG, but induction of newly synthesized heat-shock proteins by TG was not apparent on [35S]methionine-labelled gels. The alterations in protein synthesis induced by Ca(2+)-pump inhibitors were unaffected by BAPTA-AM loading, which clamped cytosolic Ca2+ at resting levels. We conclude that inhibition of intracellular Ca(2+)-pump activity can elicit a stress response, which has important implications for the interpretation of chronic use of Ca(2+)-pump inhibitors. In particular, the activation of the cellular shock response should be considered in interpreting the regulation of protein synthesis and cell survival by Ca(2+)-pump inhibitors such as TG.
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Merlie JP, Mudd J, Cheng TC, Olson EN. Myogenin and acetylcholine receptor alpha gene promoters mediate transcriptional regulation in response to motor innervation. J Biol Chem 1994; 269:2461-7. [PMID: 8300573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Several genes expressed in skeletal muscle are transcriptionally repressed by electrical activity arising from motor innervation and are rapidly induced following denervation. Among these are genes encoding the subunits of the nicotinic acetylcholine receptor (AChR) and the myogenic helix-loop-helix protein myogenin, which activates muscle-specific genes. To understand how electrical activity arising from motor innervation is converted into a transcriptional response, we have attempted to localize cis-acting sequences in the AChR alpha subunit and myogenin genes sufficient to direct activity-dependent transcription. Here we show that an 111-base pair and a 335-base pair region from the promoters of the AChR alpha subunit and myogenin genes, respectively, can confer activity-dependent regulation to a linked reporter gene in transgenic mice. The presence of binding sites for myogenic helix-loop-helix proteins in both of these regulatory regions is consistent with the hypothesis that these myogenic regulators serve as nuclear targets for the signaling cascade through which motor innervation leads to changes in gene transcription in skeletal muscle.
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Leibham D, Wong MW, Cheng TC, Schroeder S, Weil PA, Olson EN, Perry M. Binding of TFIID and MEF2 to the TATA element activates transcription of the Xenopus MyoDa promoter. Mol Cell Biol 1994; 14:686-99. [PMID: 8264638 PMCID: PMC358418 DOI: 10.1128/mcb.14.1.686-699.1994] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Members of the MyoD family of helix-loop-helix proteins control expression of the muscle phenotype by regulating the activity of subordinate genes. To investigate processes that control the expression of myogenic factors and regulate the establishment and maintenance of the skeletal muscle phenotype, we have analyzed sequences necessary for transcription of the maternally expressed Xenopus MyoD (XMyoD) gene. A 3.5-kb DNA fragment containing the XMyoDa promoter was expressed in a somite-specific manner in injected frog embryos. The XMyoDa promoter was active in oocytes and cultured muscle cells but not in fibroblasts or nonmuscle cell lines. A 58-bp fragment containing the transcription initiation site, a GC-rich region, and overlapping binding sites for the general transcription factor TFIID and the muscle-specific factor MEF2 was sufficient for muscle-specific transcription. Transcription of the minimal XMyoDa promoter in nonmuscle cells was activated by expression of Xenopus MEF2 (XMEF2) and required binding of both MEF2 and TFIID to the TATA motif. These results demonstrate that the XMyoDa TATA motif is a target for a cell-type-specific regulatory factor and suggests that MEF2 stabilizes and amplifies XMyoDa transcription in mesodermal cells committed to the muscle phenotype.
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Cheng TC, Harvey SP, Stroup AN. Purification and Properties of a Highly Active Organophosphorus Acid Anhydrolase from
Alteromonas undina. Appl Environ Microbiol 1993; 59:3138-40. [PMID: 16349054 PMCID: PMC182420 DOI: 10.1128/aem.59.9.3138-3140.1993] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A highly active organophosphorus acid anhydrolase from
Alteromonas undina
was purified to homogeneity and found to be composed of a single polypeptide chain with a molecular weight of 53,000. With diisopropylfluorophosphate as a substrate, the purified enzyme has a specific activity of ∼575 μmol/min/mg of protein. The enzyme has optimum activity at pH 8.0 and 55�C and is stimulated by sulfhydryl reducing agents and manganese. It is capable of rapidly hydrolyzing a wide range of nerve agents and several chromogenic phosphinates.
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Cheng TC, Wallace MC, Merlie JP, Olson EN. Separable regulatory elements governing myogenin transcription in mouse embryogenesis. Science 1993; 261:215-8. [PMID: 8392225 DOI: 10.1126/science.8392225] [Citation(s) in RCA: 226] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Expression of the myogenic helix-loop-helix (HLH) protein myogenin in muscle cell precursors within somites and limb buds is among the earliest events associated with myogenic lineage determination in vertebrates. Mutations in the myogenin promoter that abolish binding sites for myogenic HLH proteins or myocyte enhancer factor-2 (MEF-2) suppressed transcription of a linked lacZ transgene in subsets of myogenic precursors in mouse embryos. These results suggest that myogenic HLH proteins and MEF-2 participate in separable regulatory circuits leading to myogenin transcription and provide evidence for positional regulation of myogenic regulators in the embryo.
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DeFrank JJ, Beaudry WT, Cheng TC, Harvey SP, Stroup AN, Szafraniec LL. Screening of halophilic bacteria and Alteromonas species for organophosphorus hydrolyzing enzyme activity. Chem Biol Interact 1993; 87:141-8. [PMID: 8393735 DOI: 10.1016/0009-2797(93)90035-w] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Previously, a G-type nerve agent degrading enzyme activity was found in a halophilic bacterial isolate designated JD6.5. This organism was tentatively identified as an unknown species of the genus Alteromonas. In order to determine whether this type of enzyme activity was common in other species of Alteromonas, a screening program was initiated. A number of Alteromonas species and five halophilic bacterial isolates were cultured and their crude cell extracts screened for hydrolytic activity against several organophosphorus chemical agents and other related compounds. The samples were also screened for cross-reactivity with a monoclonal antibody raised against the purified enzyme from JD6.5 and for hybridization with a DNA probe based on its N-terminal amino acid sequence A wide spectrum of activities and reactivities were seen, suggesting a significant heterogeneity between the functionally similar enzymes that are present in these bacterial species. Enzymes of the type described here have considerable potential for the decontamination and demilitarization of chemical warfare agents.
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Cheng TC, Hanley TA, Mudd J, Merlie JP, Olson EN. Mapping of myogenin transcription during embryogenesis using transgenes linked to the myogenin control region. J Biophys Biochem Cytol 1992; 119:1649-56. [PMID: 1334962 PMCID: PMC2289748 DOI: 10.1083/jcb.119.6.1649] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
During vertebrate embryogenesis, the muscle-specific helix-loop-helix protein myogenin is expressed in muscle cell precursors in the developing somite myotome and limb bud before muscle fiber formation and is further upregulated during myogenesis. We show that cis-acting DNA sequences within the 5' flanking region of the mouse myogenin gene are sufficient to direct appropriate temporal, spatial, and tissue-specific transcription of myogenin during mouse embryogenesis. Myogenin-lacZ transgenes trace the fate of embryonic cells that activate myogenin transcription and suggest that myogenic precursor cells that migrate from the somite myotome to the limb bud are committed to a myogenic fate in the absence of myogenin transcription. Activation of a myogenin-lacZ transgene can occur in limb bud explants in culture, indicating that signals required for activation of myogenin transcription are intrinsic to the limb bud and independent of other parts of the embryo. These results reveal multiple populations of myogenic precursor cells during development and suggest the existence of regulators other than myogenic helix-loop-helix proteins that maintain cells in the early limb bud in the myogenic lineage.
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