Exclusion of CXCR4 as the cause of trapped neutrophil syndrome in Border Collies using five microsatellites on canine chromosome 19.
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Animals↗
Biomedical subjects
Q Y Zhang
Publications and source records attributed to Q Y Zhang.
Mutations in the ATP2C1 gene in Chinese patients with Hailey-Hailey disease.
Hailey-Hailey disease (HHD; MIM 16960) is a rare autosomal dominant hereditary disorder characterized by recurrent eruption of vesicles and bullae, predominantly involving the body folds. It is caused by heterozygous mutations in the ATP2C1 gene, encoding the human secretory pathway Ca2+/Mn2+-ATPase protein 1 (hSPCA1). When we studied Chinese patients with HHD, we found two different heterozygous mutations, Q506X and G353V, the former previously reported in a Hungarian patient, and the latter being a novel mutation. In a 38-year-old patient from a four-generation pedigree with a 3-year history of severe recurrent blisters, we identified a C-->T transition at nucleotide 1696, c(1696C-->T), in exon 17 of ATP2C1, resulting in a nonsenes mutation, Gln506X, which resulted in a premature termination codon. In the second patient, who represented a occurrence of sporadic Hailey-Hailey disease, a G-->T transversion of nucleotide, c(G1238T), in exon 13 of ATP2C1 was detected, which resulted in a Gly353-->Val amino acid substitution (G353V). Our molecular findings further demonstrate that the mutational events in the human ATP2C1 gene encoding the hSPCA1 pump play an important role in the pathogenesis of HHD.
Adult↗
Electron microscopic examination of the viromatrix of Rana grylio virus in a fish cell line.
Rana grylio virus (RGV), a Ranavirus belonging to the family Iridoviridae, assembles in the viromatrix which is a factory for viral genome replication and particle assembly. Ultrastructural studies of the viromatrix will clarify the pathway of assembly. The viromatrix and quantitative changes in RGV infected epithelipma papulosum cyprini (EPC) cells, one of fish cell lines, were studied by electron microscopy. It was shown that viromatrices were adjacent to the nucleus, and the electron density was lower than that of the surrounding cytoplasm. The viromatrix contained virus particles with different forms, electron-dense materials and amorphous structures which included tubules and membranous materials. Tubules were often observed in direct continuity with empty capsids. Several bundles of intermediate filaments were seen alongside the viromatrix and crystalline aggregates. Large clusters of mitochondria occurred in proximity to viromatrix. A total of 990 cells profiles were examined. The results showed that 394 cells contained viromatrix: 89.3% contained one, and 10.7% contained two to four viromatrices. The number of viromatrices increased gradually and reached a peak at 16 h p.i. The viromatrix area at 24 h p.i. increased up to 7.4 +/- 0.69 microm(2) which was three-times lower than that at 6 h p.i. The number of empty capsids within viromatrix was generally more than that of "full" particles at different time points, and there was a strong positive correlation between them.
Animals↗
Characterization of an iridovirus from the cultured pig frog Rana grylio with lethal syndrome.
Three virus isolates, RGV-9506, RGV-9807 and RGV-9808, were obtained from cultured pig frogs Rana grylio undergoing lethal infections. Previously, the first isolate, RGV-9506, was shown to be an iridovirus based on ultrastructural and morphological studies. In the present study, the original isolate, along with 2 recent ones, were more extensively characterized by experimental infection studies, histopathology, electron microscopy, serological reactivity, gel electrophoresis of viral polypeptides and DNA restriction fragments, PCR amplification, and nucleic acid sequence analysis of the major capsid protein (MCP) gene. The 3 isolates were shown to be identical to each other, and very similar to FV3, the type species of the genus Ranavirus (family Iridoviridae). These results suggest that RGV should be considered a strain of FV3, and indicate that FV3-like iridoviruses are capable of causing widespread, severe disease among cultured frogs.
Amino Acid Sequence↗
Induction of CYP1A by benzo[k]fluoranthene in human hepatocytes: CYP1A1 or CYP1A2?
While fresh human hepatocyte cultures are widely used to model hepatic cytochrome P450 (CYP) regulation and activity, their CYP1A subfamily composition induced by, e.g., polycyclic aromatic hydrocarbons is ambiguous. CYP1A1, CYP1A2, or both have been reported to be expressed, and their varied roles in chemical carcinogenesis makes resolution of which CYPs are expressed essential. We have used an immunoblot system with Bis-Tris-HCl-buffered polyacrylamide gel, which clearly resolves human CYP1A1 and CYP1A2, and polyclonal goat anti-human CYP1A1/CYP1A2 and rabbit anti-human CYP1A2 antibodies to probe the expressed CYP1A1 and CYP1A2 composition of seven individual human hepatocyte cultures induced with 5 microM benzo[k]fluoranthene (BKF) for 24 h. In six of the cultures only CYP1A1 was detected, and in the seventh both CYPs were detected. In most vehicle-treated hepatocyte cultures, neither CYP1A1 nor CYP1A2 was detected. In three additional hepatocyte cultures treated individually with BKF and 2,3,7,8,-tetrachlorodibenzo-p-dioxin (TCDD), the resultant induced CYP1A1/1A2 profiles were essentially not influenced by the nature of the inducing agents. To develop an activity-based assay to differentiate between CYP1A1 and CYP1A2 expression in human hepatocytes, our previously published R warfarin assay (Drug Metab. Disp. (1995) 23, 1339-1345) was applied to TCDD (10 nM)-treated hepatocyte culture. The low concentration of TCDD did not produce inhibition of the warfarin metabolism-such inhibition could confound the results. Based on the ratios of 6- to 8-hydroxywarfarin formed in two cultures, the ratios of CYP1A1/CYP1A2 expressed in these cultures were determined and they agreed with the ratios determined by immunoblot analysis. Thus each individual human hepatocyte culture must be characterized for induced CYP1A1 and CYP1A2 expression in studies of CYP1A activity. The warfarin assay provides a means of characterizing the cultures.
Adolescent↗
Effect of metals on polycyclic aromatic hydrocarbon induction of CYP1A1 and CYP1A2 in human hepatocyte cultures.
Environmental cocontamination by polycyclic aromatic hydrocarbons (PAHs) and metals could affect the carcinogenic consequences of PAH exposure by modifying PAH induction of PAH-bioactivating CYP1A. The effect of As, Pb, Hg, or Cd (ranked as the most hazardous environmental metals by EPA and ATSDR) on CYP1A1 and 1A2 induction by benzo[a]pyrene (BaP), benzo[b]fluoranthene (BbF), dibenzo[a,h]anthracene (DBahA), benzo[a]anthracene (BaA), and benzo[k]fluoranthene (BkF) has thus been investigated in fresh human hepatocyte cultures. Induction was probed by ethoxyresorufin-O-deethylase activity, by immunoblots, and by RT-PCR. Uptake of PAHs into the hepatocytes varied according to PAH and liver donor: 84% of 5 microM BaA and 25-40% of 5 microM DBahA was taken up in 24 h. Hepatocytes retained viability up to 1 microM Cd and 5 microM Pb, Hg, or As and 5 microM PAHs. PAH induction of CYP1A in hepatocytes was variable, some cultures expressed CYP1A1 and others CYP1A1 and 1A2, and to variable extents. Induction efficiency (relative to DMSO controls) at 2.5 microM PAH concentration was in the order BkF (7.6-fold) > DBahA (6.1 fold) > BaP (5.7 fold) > BbF (3.9-fold) > BaA (2.5-fold). All four metals (1-5 microM) decreased CYP1A1/1A2 induction by some of the PAHs with dose-, metal-, and PAH-dependency. Arsenic (5 microM) decreased induction by 47% for BaP, 68% for BaA, 45% for BbF, 79% for BkF, and 53% for DBahA. Induced CYP1A2 protein was much more extensively decreased than 1A1 protein, and CYP1A2 mRNA and, to variable extents, CYP1A1 mRNA were decreased by As. Thus the metals in PAH/metal mixtures could diminish PAH carcinogenicity by decreasing induction of their bioactivation by CYP1A1/1A2.
Arsenic↗
Metabolic characterization of the major human small intestinal cytochrome p450s.
Human small intestine epithelial cells (enterocytes) provide the first site for cytochrome P450 (CYP)-catalyzed metabolism of orally ingested xenobiotics. CYP3A4 is the major form of CYP expressed in enterocytes and CYP2C is also expressed at a significant level. In this study, we further characterized the expression of CYP3A4 and CYP2C in human enterocytes and their interindividual variations by examining the metabolic activities from 10 individuals. CYP3A4 in human jejunum microsomes, as determined by 6beta-testosterone hydroxylase activity, varied from 0.36 to 2.46 nmol/min/mg. The apparent average K(m) and V(max) values from two representative individuals were 54 microM and 3.2 nmol/min/mg, respectively. CYP2C9 and CYP2C19 in human jejunum microsomes, as determined by diclofenac 4'-hydroxylase and mephenytoin 4'-hydroxylase activities, varied over an 18-fold range (7.3-129 pmol/min/mg) and 17-fold range (0.8-13.1 pmol/min/mg), respectively. The mean apparent K(m) for diclofenac 4'-hydroxylase was 9.9 microM , whereas the apparent mean K(m) for S-mephenytoin 4'-hydroxylase was 79.3 microM . The mean intrinsic clearance (V(max)/K(m)) was approximately 130-fold greater for diclofenac 4'-hydroxylase than for mephenytoin 4'-hydroxylase. The metabolic activities of CYP2C9 and CYP2C19 were confirmed by inhibition by sulfaphenazole for CYP2C9 and ticlopidine for CYP2C19. In addition, CYP2C9 activities did not correlate with CYP3A4 activities, while CYP2C19 activities had a significant but poor correlation with those of CYP3A4. Thus the major CYP activities in human enterocytes have large interindividual variabilities that are not strongly related.
Adult↗
Polycyclic aromatic hydrocarbon/metal mixtures: effect on PAH induction of CYP1A1 in human HEPG2 cells.
Environmental polycyclic aromatic hydrocarbons (PAHs) and metals coexist, and such mixtures could affect the carcinogenicity of PAHs, possibly by modification of PAH induction of the PAH-bioactivating CYP1A. The effect on PAH-mediated CYP1A induction of arsenic, lead, mercury, or cadmium (ranked as the most hazardous environmental metals by the Environmental Protection Agency and the Agency for Toxic Substances and Disease Registry) has thus been investigated. Induction of CYP1A1 by benzo[a]pyrene (BAP), benzo[b]fluoranthene (BBF), dibenzo[a,h]anthracene (DBAHA), benzo[a]anthracene (BAA), or benzo[k]fluoranthene (BKF) was probed by ethoxyresorufin-O-deethylase activity (EROD) in 96-well plates of human HepG2 cells, by immunoblot analysis, and by reverse transcription-polymerase chain reaction. Cells rapidly took up PAHs (BAP, BKF) from medium; by 24 h only 14% remained in the medium, and no detectable PAH bound to well walls. Induction efficiency (relative to dimethyl sulfoxide controls) was in the order BKF (16-fold) > DBAHA (14-fold) > BAA (4-fold) > BAP (3-fold) > BBF (1-fold), all at 5 microM PAH. The metals did not markedly affect cell viability at concentrations of arsenic, 5 microM; lead, 50 microM; mercury, 5 microM; and cadmium, 5 microM. At 5 microM PAH concentration, all of the metals decreased levels of PAH-induced CYP1A1 activities (direct inhibition of EROD activity was excluded) by variable extents and in a PAH-dependent manner. With BAP as inducer decreases in induction were arsenic, 57%; cadmium, 82%; mercury, 4%; and lead, 20%. The decreases were not a consequence of transcriptional down-regulation. One possible conclusion is that these metals could diminish PAH carcinogenic potential by decreasing PAH-mediated induction of their bioactivation by CYP1A1.
Base Sequence↗
[Studies on the chemical constituents of Carduus crispus L].
OBJECTIVE: To study the chemical constituents of Carduus crispus. METHOD: Using chromatographic methods to isolate compounds and using chemical and spectral methods to elucidate the structures of the isolated compounds. RESULT: Eight compounds were elucidated as beta-amyrin palmitate, taraxastery acetate, luteolin-7-O-alpha-L-rhamanopyranosyl-(1-->2)-beta-D-glucopyranoside, luteolin-7-O-beta-D-glucopyranoside, triacontanic acid, beta-sitosterol, stigmasterol and stigmast-7-en-3 beta-ol. CONCLUSION: All the compounds were obtained from this plant for the first time.
Carduus↗
Human cytochrome P450 CYP2A13: predominant expression in the respiratory tract and its high efficiency metabolic activation of a tobacco-specific carcinogen, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone.
The human CYP2A subfamily comprises three genes, CYP2A6, CYP2A7, and CYP2A13. CYP2A6 is active toward many carcinogens and is the major coumarin 7-hydroxylase and nicotine C-oxidase in the liver, whereas CYP2A7 is not functional. The function of CYP2A13 has not been characterized. In this study, a CYP2A13 cDNA was prepared by RNA-PCR from human nasal mucosa and was translated using a baculovirus expression system. In a reconstituted system, the expressed CYP2A13 was more active than CYP2A6 in the metabolic activation of hexamethylphosphoramide, N,N-dimethylaniline, 2'-methoxyacetophenone, and N-nitrosomethylphenylamine but was much less active than CYP2A6 in coumarin 7-hydroxylation. Of particular interest, CYP2A13 was highly active in the metabolic activation of a major tobacco-specific carcinogen, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, with a catalytic efficiency much greater than that of other human cytochrome P450 isoforms examined previously. The tissue distribution of CYP2A13 was determined with isoform-specific RNA-PCR. CYP2A13 mRNA was detected in liver and a number of extrahepatic tissues, including nasal mucosa, lung, trachea, brain, mammary gland, prostate, testis, and uterus, but not in heart, kidney, bone marrow, colon, small intestine, spleen, stomach, thymus, or skeletal muscle. Quantitative PCR analysis further revealed that CYP2A13 mRNA is expressed at the highest level in the nasal mucosa, followed by the lung and the trachea. Together, these findings suggest that CYP2A13 plays important roles in xenobiotic toxicity and tobacco-related tumorigenesis in the human respiratory tract.
Adolescent↗
Isolation of a lethal rhabdovirus from the cultured Chinese sucker Myxocyprinus asiaticus.
A rhabdovirus was found to be associated with a lethal hemorrhagic disease in the cultured Chinese sucker Myxocyprinus asiaticus Bleeker. The rhabdovirus was amplified and isolated from the infected GCO (grass carp ovary) cells. In ultrathin sections of liver cells from the diseased fish, the virus particles exhibited the characteristic bacilliform morphology, and budded through vesicle membranes of the infected cells. The isolated rhabdovirus particles were found to have a bacilliform morphology with 2 rounded ends rather than a typical flat base. The virus particles were measured and ranged in size from 150 to 200 nm in length and 50 to 60 nm in diameter. Most other characteristics, including their size, extensive virus infectivity to fish cell lines, strong cytopathogenic effects, stability at high temperatures, vesicle formation in infected cells, structure protein electrophoretic patterns and the presence of an RNA genome, very closely resembled those of other fish rhabdoviruses. At present it is not known if this is a novel virus species or if it is an isolate of a known fish rhabdovirus. Until a confirmed identification can be made, we will temporarily refer to this virus as Chinese sucker rhabdovirus (CSRV).
Animals↗
Expression of biotransformation enzymes in human fetal olfactory mucosa: potential roles in developmental toxicity.
High levels of cytochrome P450 are present in the olfactory mucosa (OM) in mammalian animals and contribute to the known tissue-selective toxicity of numerous chemical compounds. Olfactory toxicity in the perinatal period may have a greater impact on behavior, growth, and development than in adults. To establish a molecular basis for determining the risk of developmental toxicity in OM, the expression of several cytochrome P450 enzymes, as well as NADPH-cytochrome P450 reductase and microsomal epoxide hydrolase, was examined in hepatic and nasal microsomes prepared from human fetal tissues at gestational day 91-125. The relative microsomal concentrations of these biotransformation enzymes were determined on immunoblots. Expression of CYP2A, CYP2J2, the reductase, and epoxide hydrolase was detected in both OM and liver. The microsomal levels of these enzymes were generally lower in OM than in liver of the same fetuses, except for the CYP2A-related proteins, which were expressed in OM at much higher levels. OM expression of CYP2A6, CYP2A13, CYP2B6, and CYP2J2 mRNAs was detected using RNA-PCR. These results document, for the first time, prenatal expression of xenobiotic-bioactivating cytochrome P450 enzymes in human OM and suggest that the human fetal OM may be a preferred target tissue for the toxicity of maternally derived chemical compounds that are activated by the CYP2A enzymes.
Biotransformation↗
Identification and functional characterization of a conserved, nuclear factor 1-like element in the proximal promoter region of CYP1A2 gene specifically expressed in the liver and olfactory mucosa.
CYP1A2 is a major cytochrome P-450 isoform in the liver and the olfactory mucosa but is essentially not expressed in other tissues. A nuclear factor 1 (NF-1) -like element was identified in the proximal promoter region of rat, mouse, rabbit, and human CYP1A2 genes through data base analysis. In vitro DNase I footprinting with a -211 to +81 probe from the rat CYP1A2 gene and nuclear extracts from rat liver and olfactory mucosa revealed a single protected region corresponding to the NF-1-like element at -129 to -111. Protein binding to this NF-1-like element was tissue-selective and was confirmed by in vivo footprinting in native chromatin from rat liver. Multiple DNA-binding complexes were detected in gel-shift assays using the CYP1A2 NF-1-like element and nuclear extracts from liver and olfactory mucosa, all of which were supershifted in the presence of an anti-NF1 antibody. The NF-1-like element was essential for transcriptional activity of the CYP1A2 gene in an in vitro transcription assay using nuclear extracts from the two tissues. Thus, members of the NF-1 family of transcription factors may play an important role in the tissue-selective expression of the CYP1A2 gene in the liver and olfactory mucosa.
Animals↗
A new triterpenoid from Stelmatocrypton khasianum.
A new triterpenoid, 2alpha-,3beta,-,19alpha-trihydroxy-urs-12-ene-24,28-dioic acid (1), along with two known compounds. 3beta-acetoxy-urs-12-ene-11-one (2) and vomifoliol (3), was isolated from stems of Stelmatocryprton khasianum for the first time. Their structures were elucidated on the basis of chemical and spectroscopic methods.
Drugs, Chinese Herbal↗
Human cytochrome P-450 metabolism of retinals to retinoic acids.
Retinoic acids have important pleiotropic biological effects and thus the potential for human cytochrome P-450s (CYPs) to mediate retinoic acid synthesis was investigated. We examined the retinoic acid synthetic activity of human cDNA-expressed CYP1A1, 1A2, 1B1, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, 3A4, 3A4+ cytochrome b(5) (b(5)), 3A5, and 4A11, expressed individually in insect cells together with NADPH-P-450 reductase. Only CYP1A1, 1A2, 1B1, and 3A4+b(5) converted all-trans-retinal (20 microM) to all-trans-retinoic acid with turnover numbers of 0.53, 0.18, 0.20, and 0.41 nmol/min/nmol P-450, respectively. With 9-cis-retinal as substrate, CYP1A2 exhibited a turnover number of 1.58 nmol/min/nmol P-450 whereas CYP1A1, 2C19, and 3A4+b(5) had turnover numbers of 0.40, 0.27, and 0.41 nmol/min/nmol P-450, respectively. For CYP3A4 activities with both retinals, b(5) was required. Kinetic analyses revealed that CYP1A1, 1A2, and 3A4+b(5) with all-trans-retinal had apparent K(m) values of 55, 356, and 255 microM, and V(max) values of 2.0, 8.3, and 6.3 nmol/min/nmol P-450, respectively, and with 9-cis-retinal had K(m) values of 77, 91, and 368 microM, and V(max) values of 2.7, 9.7, and 7.6 nmol/min/nmol P-450, respectively. The 9-cis retinoic acid synthetic activity of a group of 12 human liver microsomes correlated only with the CYP1A2 activity (r = 0.96), implicating CYP1A2 in human liver microsomal metabolism of 9-cis- retinal to 9-cis-retinoic acid. These studies have indicated that human CYPs are capable of catalyzing retinal to retinoic acid metabolism, but the physiological relevance of this metabolism is still unclear.
Animals↗
Induction of mouse CYP2J by pyrazole in the eye, kidney, liver, lung, olfactory mucosa, and small intestine, but not in the heart.
We have recently shown that rat CYP2J4 is inducible by pyrazole in liver, small intestine, and olfactory mucosa. The aim of the present study was to determine whether mouse CYP2Js are also inducible by pyrazole, which was known to induce CYP2A5 in mouse liver and kidney, but not in lung or olfactory mucosa. CYP2J proteins were detected in mouse liver, lung, kidney, heart, eye, olfactory mucosa, and small intestine by immunoblot analysis with an anti-CYP2J4 antibody. The microsomal level of the CYP2J4-related P450s in various mouse tissues ranked in the order of small intestine > olfactory mucosa > liver > kidney > or = heart > lung > eye. Induction of the CYP2J proteins was observed in the eye, liver, lung, kidney, olfactory mucosa, and small intestine, but not in the heart, after daily i.p. injection of pyrazole at 120 or 200 mg/kg for 3 days. CYP2J proteins were induced similarly in C57BL/6 and DBA/2 mice. CYP2A5 was detected in the small intestine in addition to liver and olfactory mucosa; however, treatment with pyrazole induced CYP2A5 in the liver, but not in the olfactory mucosa or the small intestine. Induction of CYP2J mRNAs was also observed by RNA blot analysis with a CYP2J4 cDNA probe. RNA-polymerase chain reaction analysis showed that, in both untreated and pyrazole-treated mice, CYP2J5 was expressed in the kidney and liver, but not in the other tissues examined, whereas CYP2J6 was detected in all tissues examined. The different tissue selectivities in CYP2A5 and CYP2J induction by pyrazole suggest involvement of different regulatory mechanisms.
Animals↗
[Construction of a transformation-competent artificial chromosome (TAC) library of a wheat-Haynaldia villosa translocation line].
Transformation-competent artificial chromosome (TAC) vector is able to clone and transfer large DNA fragments in plants and is a powerful tool for plant gene isolation and transformation. To clone important genes from wheat, a TAC genomic library was constructed from nuclear DNA of a 6VS/6AL wheat-Haynaldia villosa translocation line that harbor the gene Pm21 for resistance to powdery mildew. The library consists of 2.1 x 10(6) clones with an average DNA insert size of 35 kb, and represents in total 4.9 genome equivalents. The library was stored as clone pools in 96-well plates, and each pool contained about 1000 clones. TAC clones containing gene(s) of interest can be screened by a pooled-PCR/colony-hybridization strategy.
Chromosomes, Artificial↗
[Genetic improvement of cotton varieties in Huang-Huai region in China since 1950's. III. Improvement on agronomy properties, disease resistance and stability].
Data from a set of 5-location and 2-year experiments on 10 representative historical cotton varieties and the data of Huang-Huai Regional Cotton Trials from 1973 to 1996 were analyzed to estimate the effects of genetic improvement in agronomy properties, disease resistance and stability of cotton in Huang-Huai Region in China. The results indicated that a great genetic progress of earliness and disease resistance had been achieved by breeding programs since 1950's. The maturity was shortened 3-5 days; The rate of preforst yield was increased about 7 percentages. The problem of resistance to Fususium wilt has been solved and the resistance to Verticillum wilt was improving. Some progress in stability of cotton varieties also has been achieved by breeding programs since 1950.
China↗