Single and binary-combined toxicity of methamidophos, acetochlor and copper acting on earthworms Esisenia foelide.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
Q Zhou
Publications and source records attributed to Q Zhou.
No evidence for linkage and/or association of human alpha2-HS glycoprotein gene with bone mineral density variation in Chinese nuclear families.
Osteoporosis is an important health problem in the world. Alpha2-HS glycoprotein (AHSG) is involved in bone formation and metabolism and has been considered as an important candidate gene for osteoporosis. In this study, we simultaneously tested linkage and/or association of the AHSG gene with the variation of bone mineral density (BMD), an important risk factor for osteoporosis. A sample of 1,260 subjects from 401 Chinese nuclear families (including both parents and their daughters) were studied. The daughters' ages ranged from 20 to 45 years. All the subjects were genotyped by PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) at polymorphic Sac I site inside the exon 7 of the AHSG gene. This polymorphism involves a nucleotide substitution of C to G at the middle nucleotide of the codon at amino acid position 238, resulting in the replacement of threonine (ACC) with serine (AGC). BMD was measured at the lumbar spine and hip region by dual-energy X-ray absorptiometry (DXA). Using the QTDT (quantitative trait transmission disequilibrium test), we found no significant results for association or linkage between the AHSG gene and BMD variation at the spine or hip. Our data provided no evidence to support the AHSG gene as a quantitative trait locus (QTL) for the BMD variation in a Chinese population.
Absorptiometry, Photon↗
Role of cell surface components on Cu2+ adsorption by Pseudomonas putida 5-x isolated from electroplating effluent.
A gram-negative bacterium Pseudomonas putida 5-x with high Cu2+ accumulating capability was isolated from electroplating effluent in Kwun Tong, Hong Kong. The pretreated cells without superficial layer-capsule, isolated cell envelopes and the separated peptidoglycan layer materials were obtained from fresh P. putida 5-x cells, their Cu2+ adsorption capacities and properties were compared with that of the fresh cells. Pretreatment by 0.1 mol L(-1) HCl enhanced Cu2+ adsorption capacity due to the degradation of cell superficial layer-capsule of P. putida 5-x cells. Isolated cell envelopes possessed five times more Cu2+ adsorption capacity than that of fresh intact cell. The Cu2+ adsorption of separated peptidoglycan layer materials indicated that the peptidoglycan layer only played 10-15% part of the Cu2+ adsorption capacity, and implied other cell surface components such as outer membrane or inner membrane might play an important role in such high Cu2+ binding of the cell envelopes. The adsorption process of fresh cells, pretreated cells and cell envelopes of P. putida 5-x could be described with Freundlich isotherm, while the adsorption of Cu2+ by separated peptidoglycan layer materials was better described with Langmuir isotherm.
Adsorption↗
Tests of linkage and association of the COL1A2 gene with bone phenotypes' variation in Chinese nuclear families.
In the present study, we simultaneously test linkage and/or association of the collagen type I alpha 2 (COL1A2) gene with bone mineral density (BMD) and bone area. A total of 1280 subjects from 407 Chinese nuclear families (including both parents and their daughters) were genotyped for an intragenic marker MspI in the COL1A2 gene. BMD and bone area at the lumbar spine and hip were measured by dual-energy X-ray absorptiometry. Applying the QTDT (quantitative transmission disequilibrium test) program, we performed tests for population stratification, within-family association (via transmission disequilibrium test), total association, linkage, and linkage while modeling association. Significant or marginal within-family associations were found with BMD at the lumbar spine (P = 0.013), trochanter (P = 0.004), and total hip (P = 0.053) and with bone area at the intertrochanteric region (P = 0.024) and total hip (P = 0.048). The positive associations were confirmed in permutations except for bone area at total hip (P > 0.10). A small proportion (<1%) of the population variance of bone phenotypes can be explained by the MspI polymorphism; however, it may be underestimated given the significant population stratification detected in our sample. Due to the limited number of sib pairs in this sample, we did not find evidence of linkage. In summary, the MspI polymorphism is likely to be in linkage disequilibrium with a nearby functional mutation affecting BMD and bone area.
Adult↗
Bacterial virus phi29 pRNA as a hammerhead ribozyme escort to destroy hepatitis B virus.
The DNA-packaging pRNA of bacterial virus phi29, which forms dimers and then hexamers, contains two independent tightly self-folded domains. Circularly permuted pRNAs were constructed without impacting pRNA folding. Connecting the pRNA 5'/3' ends with variable sequences did not disturb its folding and function. These unique features, which help prevent two common problems - exonuclease degradation and misfolding in the cell, make pRNA an ideal vector to carry therapeutic RNAs. A pRNA-based vector was designed to carry hammerhead ribozymes that cleave the hepatitis B virus (HBV) polyA signal. The chimeric HBV-targeting ribozyme was connected to the pRNA 5'/3' ends as circularly permuted pRNA. Two cis-cleaving ribozymes were used to flank and process the chimeric ribozyme. The hammerhead ribozyme including its two arms for HBV targeting was able to fold correctly while escorted by the pRNA. The chimeric ribozyme cleaved the polyA signal of HBV mRNA in vitro almost completely. Cell culture studies showed that the chimeric ribozyme was able to enhance the inhibition of HBV replication when compared with the ribozyme not escorted by pRNA, as demonstrated by Northern blot and e-antigen assays. pRNA could also carry another hammerhead ribozyme to cleave other RNA substrate. These findings suggest that pRNA can be used as a vector for imparting stability to ribozymes, antisense, and other therapeutic RNA molecules in vivo.
Base Sequence↗
A catalogue of molecular, physiological and symbiotic properties of soybean-nodulating rhizobial strains from different soybean cropping areas of China.
We have analysed 198 fast-growing soybean-nodulating rhizobial strains from four different regions of China for the following characteristics: generation time; number of plasmids; lipopolysaccharide (LPS), nodulation factors (LCOs) and PCR profiles; acidification of growth medium; capacity to grow at acid, neutral, and alkaline pH; growth on LC medium; growth at 28 and 37 degrees C; melanin production capacity; Congo red absorption and symbiotic characteristics. These unbiased analyses of a total subset of strains isolated from specific soybean-cropping areas (an approach which could be called "strainomics") can be used to answer various biological questions. We illustrate this by a comparison of the molecular characteristics of five strains with interesting symbiotic properties. From this comparison we conclude, for instance, that differences in the efficiency of nitrogen fixation or competitiveness for nodulation of these strains are not apparently related to differences in Nod factor structure.
Bacterial Proteins↗
The biodegradation of 1,3-dichlorobenzene by an adapted strain Bacillus cereus PF-11 derived from town-gas industrial effluent.
In the present study, an adapted bacterium PF-11 with high 1,3-dichlorobenzene degradation capability was isolated from town-gas industrial effluent through continuous introducing of N-methyl-N'-nitro-N-nitrosoquanidine (NTG). In suitable condition, a degradation rate of 32 mg L(-1) d(-1) of 1,3-dichlorobenzene was obtained by strain PF-11 with effective chlorion release. Strain PF-11 was tentatively identified as gram-positive Bacillus cereus. The substrate specificity of the strain PF-11 was relatively low, and the degradation rate for different chlorobenzenes was in the order of monochlorobenzene > 1,3-dichlorobenzene > 1,2-dichlorobenzene. Initial oxidation step was molecular oxygen attacking chlorobenzene ring catalyzed by dioxygenase.
Adaptation, Physiological↗
Both stress experience and age determine the impairment or enhancement effect of stress on spatial memory retrieval.
It has been documented that stress or glucocorticoids have conflicting effects on memory under different conditions. However, it is not fully understood why stress can either impair or enhance memory. Here, we have examined the performance of six age groups of Wistar rats in a water maze spatial task to evaluate the effects of stress under different conditions. We found that the impairment or enhancement effect of an 'elevated platform' (EP) stress on memory was dependent on previous stress experience and on age. EP stress impaired memory retrieval in water maze naive animals, but enhanced rather than impaired memory retrieval in young water maze stress-experienced animals. Furthermore, exogenously applied corticosterone or foot shock stress before water maze training prevented the impairment of memory retrieval that should be induced by treatment with corticosterone or foot shock before the 'probe trial'. Again, memory retrieval was enhanced in young animals under these conditions, and this enhancement can be prevented by the glucocorticoid receptor antagonist RU 38486. Thus, glucocorticoid receptor activation not only induced impairment of memory but also increased the capacity of young animals to overcome a later stress. The present findings suggest that the effect of stress on memory can be switched from impairment to enhancement dependent on both stress experience and age.
Aging↗
Nutrient removal by the integrated use of high rate algal ponds and macrophyte systems in China.
High Rate Algal Ponds (HRAP) were operated at pilot scale to investigate the performance of HRAP under the temperate climate conditions of Shanghai, China. The results indicated that the HRAP gave good efficiency for nutrient removal, especially during summer. With a retention time of 4 or 8d according to the season, the annual average removal efficiencies for COD, NH4-N and PO4-P were 50%, 87% and 40%, respectively. The multi-factor linear models showed the relationships between nutrient removal efficiency and influencing factors. Using a macrophyte pond to separate algae from HRAP can achieve concentrations of COD, TP and TKN in the effluent at around 50 mg/L, 1.5 mg/L and 5 mg/L respectively.
Biodegradation, Environmental↗
Concentration dependent stereoselectivity of propafenone N-depropylation metabolism with human hepatic recombinant CYP1A2.
Concentration dependency of stereoselective N-depropylation metabolism of propafenone was studied by using transgenic cell line expressing human CYP1A2. Enantiomers of propafenone and N-depropylpropafenone were separated and assayed simultaneously by RP-HPLC with precolumn GITC chiral derivatization. The experimental results showed that CYP1A2 was involved in enantioselective N-depropylation of propafenone and that the metabolic stereoselectivity depends on substrate concentration. For racemic propafenone, stereoselectivity was observed at low substrate concentration and was not seen at high substrate concentration. For individual isomers, S-(+)-propafenone was metabolized faster than its antipode at higher enantiomer concentrations and R-(-)-propafenone was eliminated faster than its antipode at lower enantiomer concentrations. There is interaction between S- and R-propafenone. R-(-)-propafenone inhibited the metabolism of S-(+)-propafenone with IC50 0.225 mmol/L for human CYP1A2.
Anti-Arrhythmia Agents↗
Chiral reversed phase high-performance liquid chromatography for determining propranolol enantiomers in transgenic Chinese hamster CHL cell lines expressing human cytochrome P450.
An enantioselective assay for S-(-)- and R-(+)-propranolol in transgenic Chinese hamster CHL cell lines, expressing human cytochrome P450 (CYP), was developed. The method involves extraction of propranolol from the S(9) incubates, using S-(+)-propafenone as internal standard, chiral derivatization with 2,3,4,6-tetra-O-beta-D-glucopranosyl isothiocyanate and quantitation by reversed phase high-performance liquid chromatography system with UV detection (lambda=220 nm). A baseline separation of propranolol enantiomers was achieved on a 5-microm reverse-phase ODS column, with a mixture of methanol/water/glacial acetic acid (67:33:0.05, v/v) as mobile phase. The assay is linear from 5 to 500 microM for each enantiomer. The analytical method affords average recoveries of 99.2% and 98.8% for S-(-)- and R-(+)-propranolol, respectively. The limit of quantitation for the method is 5 microM for both S-(-)- and R-(+)-propranolol. The reproducibility of the assay is satisfactory (RSD < 10%). The method allowed study of the depletion of S-(-)- and R-(+)-propranolol in transgenic Chinese hamster CHL cell lines expressing CYP3A4, CYP2C18 and CYP2C9.
Animals↗
Effect of combined treatment with nandrolone and cocaine on the NMDA receptor gene expression in the rat nucleus accumbens and periaqueductal gray.
OBJECTIVE: Anabolic androgenic steroids (AAS) have been suggested to sensitize mechanisms involved in drug dependency and aggressive behaviour. Nucleus accumbens and periaqueductal gray (PAG) are believed to be critical in the functional anatomy of these two phenomena, which are partly mediated by the NMDA receptor. This study was undertaken in order to determine the relationship between the effect of AAS and cocaine (given alone or in combination) on the gene expression of the NMDA receptor subtype NR1 in the rat nucleus accumbens and PAG. METHOD: Male rats were subjected to 2 weeks of daily doses of cocaine and the anabolic-androgenic steroid nandrolone, administrated separately or in combination, and the effect on the mRNA expression for the NMDA receptor NR1 subunit was studied by Northern blot analysis. RESULTS: In the nucleus accumbens, injection of cocaine alone and the combination of cocaine and nandrolone caused a significant decrease in the NR1 mRNA level compared with that of control rats. The combined treatment significantly down-regulated the transcript in the PAG compared with the groups injected with vehicle, nandrolone or cocaine alone. CONCLUSION: It was concluded that AAS combined with cocaine may induce additive increases in glutamatergic activity in these brain areas, supporting the notion that these steroids can sensitize mechanisms involved in the reward and the expression of aggression.
Anabolic Agents↗
Changes of TGFbeta1 and TGFbetaRII expression in esophageal precancerous and cancerous lesions: a study of a high-risk population in Henan, northern China.
The level of transforming growth factor beta1 (TGFbeta1) and transforming growth factor betaII receptor (TGFbetaRII) was determined immunohistochemically in normal tissues and tissues with different severities of lesions (basal cell hyperplasia, BCH; dysplasia, DYS; carcinoma in situ, CIS; and squamous cell carcinoma, SCC) from surgically resected human esophagi and esophageal biopsies of symptom-free subjects. The samples were from an area with high esophageal cancer incidence in northern China (Linzhou, formerly Linxian, and nearby county Huixian in Henan Province). Peroxidase immunostain (ABC) and conventional hematoxylin and eosin stain were used. The tissue sections were incubated with antibodies of TGFbeta1 and TGFbetaRII overnight. The immunoreactivity was observed in cytoplasm of the esophageal specimen. From normal to BCH to DYS to CIS and to SCC, the positive immunostaining rates for TGFbeta1 increased significantly (P < 0.05). A linear correlation between the positive immunostaining rates of TGFbeta1 and the different lesions was observed (P < 0.05). From well- to moderately- and poorly differentiated SCC, the positive immunostaining rates for TGFbeta1 decreased gradually, but the difference was not significant (P > 0.05). In contrast, with the lesions progressing from normal to BCH to DYS to CIS and to SCC, the positive immunostaining rates for TGFbetaRII decreased significantly (P < 0.05). From well- to moderately- and poorly differentiated SCC, the positive immunostaining rates for TGFbetaRII decreased significantly (P < 0.05). There was a linear correlation between the positive rates of TGFbetaRII and different lesions and SCC differentiation (P < 0.05). The present results indicated that the alterations of TGFbeta1 and TGFbetaRII is a frequent event in esophageal multistage carcinogenesis, the absent or lower expression of TGFbetaRII may lead to the loss of cell proliferation control by TGFbeta1 and the overexpression of TGFbeta1 may be a negative feedback response caused by the lower expression of TGFbetaRII protein.
Adult↗
Endoscopic screening and determination of p53 and proliferating cell nuclear antigen in esophageal multistage carcinogenesis: a comparative study between high- and low-risk populations in Henan, northern China.
The objective of this study was to characterize the histologic changes from endoscopic screening for early esophageal cancer (EC) on subjects at high-incidence area (HIA) and low-incidence area (LIA) in Henan, China, and to further compare the changes in p53 and proliferating cell nuclear antigen (PCNA) in the multistage of human esophageal carcinogenesis from these two populations. The detection rate of basal cell hyperplasia (BCH) and dysplasia (DYS) was higher in the subjects from HIA than in those from LIA. Out of the 1568 symptom-free subjects examined at HIA, 10 (0.6%) cases with early squamous cell carcinoma (SCC) were identified. Immunoreactivity of p53 and PCNA was observed in cell nuclei of esophageal biopsies and surgically resected esophageal cancer specimens both in HIA and LIA. With the lesions progressed from normal epithelium to BCH to DYS to SCC, the positive-immunostaining cells expanded from basal layer to superficial layer, and the number of positive cells/mm2 for p53 and PCNA increased, and was significantly higher in HIA than in LIA among the similar morphological lesions (P < 0.01). The number of p53 positive cells/mm2 in SCC from HIA was almost fivefold higher than SCC from LIA (P < 0.01). The remarkable difference was also observed between HIA and LIA in DYS and BCH. The present results indicate that p53 protein accumulation is an important early biomarker for identifying high-risk subjects for EC.
Adult↗
Fluorescence-based functional assay for Wnt/beta-catenin signaling activity.
Aberrant activation of beta-catenin signaling has been implicated in the development of human cancers. As a Wnt signal transducer, beta-catenin forms a complex with the lymphocyte enhancer-binding factor/T cell factor transcription factor and activates downstream targets that promote cell proliferation. Here we developed a Wnt-dependent beta-catenin-mediated heterologous transactivation system, which consisted of a chimeric transcription factor constructed by fusing the GAL4 DNA-binding domain with the full-length beta-catenin, and a GAL4-responsive reporter expressing GFP. The chimeric transcription factor was highly unstable and exerted no detectable transactivating effect on the GAL4-responsive reporter. However, lithium and Wnt1 significantly stabilized this chimeric transactivator, indicating that this transactivation system is regulated by beta-catenin in a Wnt-responsive fashion. Thus, this transactivation system could be used as a functional reporter to identify potential upstream factors that deregulate beta-catenin signaling during tumorigenesis, as well as to screen for potential anti-cancer agents that specifically inhibit beta-catenin signaling in human tumors.
Adenocarcinoma↗
Cellular signaling mechanisms underlying pharmacological action of Bak Foong Pills on gastrointestinal secretion.
Bak Foong Pills (BFP, also known as Bai Feng Wan) is an over-the-counter traditional Chinese medicine that has long been used for treating gynecological disorders and improving overall body functions, including gastrointestinal (GI) function. However, the cellular signaling mechanism underlying BFP action, especially on the GI tract, has not been elucidated. In the present study, the human colonic epithelia cell line T(84) was used as a model to investigate the effect of BFP ethanol extract on ion transport in conjunction with the short-circuit current (I(SC)) technique. The results showed that the apical addition of BFP extract produced a concentration-dependent (10-1,000 microg/ml, EC(50) = 120 microg/ml) increase in I(SC). The maximal response was observed at 500 microg/ml with an increase in I(SC) of 24.4 +/- 2.3 microA/cm(2) and apical conductance. The BFP-induced I(SC) was not observed when extracellular Cl(-) was replaced or when treated with Bumetanide (100 microM), an inhibitor of the Na(+)-K(+)-2Cl(-) cotransporter. The BFP-induced I(SC) was insensitive to the Na(+) channel blocker, amiloride, but partially inhibited by the Cl(-) channel blocker, DIDS (100 microM), and completely blocked by DPC (2 mM) or glibenclamide (1 mM) with a significant reduction in the apical conductance. The BFP-induced I(SC) could be mimicked by forskolin (10 microM), but inhibited by a pretreatment of the cells with adenylate cyclase inhibitor, MDL-12330A (10 microM). Pretreatment with EGTA (5 mM) and thapsigargin (10 microM) decreased the BFP-induced I(SC) by 10%. These results demonstrated that BFP ethanol extract exerted a stimulatory effect on gastrointestinal Cl(-) secretion by predominantly activating adenylate cyclase and apical cAMP-dependent Cl(-) channels, with minor contributions from calcium-dependent Cl(-) channels. The effect of BFP may be explored to treat GI disorders such as constipation.
Adenylyl Cyclases↗
Multiple interactions of the cytosolic polyproline region of the CD95 ligand: hints for the reverse signal transduction capacity of a death factor.
The CD95/Fas/Apo-1 ligand is expressed on activated lymphocytes, NK cells, platelets, certain immune-privileged cells and some tumor cells and induces apoptosis through the death receptor CD95/Fas/Apo-1. In murine T cells, membrane-bound CD95L (Fas ligand) also acts as a costimulatory receptor to coordinate activation and function in vivo. The molecular basis for this reverse signal transduction is yet unknown. In the present report, we identify individual interaction domains of enzymes and adapter molecules that selectively interact with full-length CD95L from transfectants and human T cells. These results may help to explain the costimulatory capacity of CD95L.
Amino Acid Sequence↗
The 7SK small nuclear RNA inhibits the CDK9/cyclin T1 kinase to control transcription.
The human positive transcription elongation factor P-TEFb, consisting of a CDK9/cyclin T1 heterodimer, functions as both a general and an HIV-1 Tat-specific transcription factor. P-TEFb activates transcription by phosphorylating RNA polymerase (Pol) II, leading to the formation of processive elongation complexes. As a Tat cofactor, P-TEFb stimulates HIV-1 transcription by interacting with Tat and the transactivating responsive (TAR) RNA structure located at the 5' end of the nascent viral transcript. Here we identified 7SK, an abundant and evolutionarily conserved small nuclear RNA (snRNA) of unknown function, as a specific P-TEFb-associated factor. 7SK inhibits general and HIV-1 Tat-specific transcriptional activities of P-TEFb in vivo and in vitro by inhibiting the kinase activity of CDK9 and preventing recruitment of P-TEFb to the HIV-1 promoter. 7SK is efficiently dissociated from P-TEFb by treatment of cells with ultraviolet irradiation and actinomycin D. As these two agents have been shown to significantly enhance HIV-1 transcription and phosphorylation of Pol II (refs 6,7,8), our data provide a mechanistic explanation for their stimulatory effects. The 7SK/P-TEFb interaction may serve as a principal control point for the induction of cellular and HIV-1 viral gene expression during stress-related responses. Our studies demonstrate the involvement of an snRNA in controlling the activity of a Cdk-cyclin kinase.
Cyclin T↗