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161.
David Tsang Cindy S. Y. Tung Vincent T. F. Yeung Clive S. Cockram 《Regulatory peptides》1997,70(2-3):91-96
The effect of endothelin-3 (ET-3) on C-type natriuretic peptide (CNP)-induced guanosine 3′,5′-cyclic monophosphate (cGMP) was examined in C6 glioma cells, CNP-induced cGMP formation was both time- and dose-dependent, with an EC50 value of about 10 nM. While ET-3 and phorbol 12-myristate 13-acetate (PMA) had no effect on basal cGMP production, both compounds were potent inhibitors of CNP-induced cGMP formation, with IC50 values of approximately 10 and 2 nM, respectively. Although protein kinase C (PKC) inhibitors had no effect on basal cGMP formation, Ro 31-8220, a PKC inhibitor, reversed the ET-3 inhibition on CNP-induced cGMP formation by 63% and that of PMA almost completely. Our findings suggest that stimulation of cGMP formation by CNP in C6 glioma cells is negatively modulated by PKC activation, and that the inhibitory action of ET-3 on CNP-stimulated cGMP formation is mediated partly by PKC. 相似文献
162.
Bullock SA Platholi J Gjyrezi A Heerdt PM Tung HY Hemmings HC 《Biochemical and biophysical research communications》2007,358(1):140-144
Neurabin is a brain-specific actin and protein phosphatase-1 (PP-1) binding protein that inhibits the purified catalytic subunit of protein phosphatase-1 (PP-1(C)). However, endogenous PP-1 exists primarily as multimeric complexes of PP-1(C) bound to various regulatory proteins that determine its activity, substrate specificity, subcellular localization and function. The major form of endogenous PP-1 in brain is protein phosphatase-1(I) (PP-1(I)), a Mg(2+)/ATP-dependent form of PP-1 that consists of PP-1(C), the inhibitor-2 regulatory subunit, an activating protein kinase and other unidentified proteins. We have identified four PP-1(I) holoenzyme fractions (PP-1(IA), PP-1(IB), PP-1(IC), and PP-1(ID)) in freshly harvested pig brain separable by poly-L-lysine chromatography. Purified recombinant neurabin (amino acid residues 1-485) inhibited PP-1(IB) (IC(50)=1.1 microM), PP-1(IC) (IC(50)=0.1 microM), and PP-1(ID) (IC(50)=0.2 microM), but activated PP-1(IA) by up to threefold (EC(50)=40 nM). The PP-1(IA) activation domain was localized to neurabin(1-210). Our results indicate a novel mechanism of PP-1 regulation by neurabin as both an inhibitor and an activator of distinct forms of PP-1(I) in brain. 相似文献
163.
Requirement for Phosphoglucose Isomerase of Xanthomonas campestris in Pathogenesis of Citrus Canker 下载免费PDF全文
A mutant (XT906) of Xanthomonas campestris pv. citri, the causal agent of citrus canker, was induced by insertion of the transposon Tn5tac1 and isolated. This mutant did not grow or elicit canker disease in citrus leaves but was still able to induce a hypersensitive response in a nonhost plant (the common bean). The mutant was also unable to grow on minimal medium containing fructose or glycerol as the sole carbon source. A 2.5-kb fragment of wild-type DNA that complemented the mutant phenotype of XT906 was isolated. Sequence analysis revealed that this DNA fragment encoded a protein of 562 amino acids that shows homology to phosphoglucose isomerase (PGI). Enzyme activity assay confirmed that the encoded protein possesses PGI activity. Analysis of the activity of the promoter of the pgi gene revealed that it was inhibited by growth in complex medium but induced by culture in plant extract. These results demonstrate that PGI is required for pathogenicity of X. campestris pv. citri. 相似文献
164.
P W Mesner K C Bible L M Martins T J Kottke S M Srinivasula P A Svingen T J Chilcote G S Basi J S Tung S Krajewski J C Reed E S Alnemri W C Earnshaw S H Kaufmann 《The Journal of biological chemistry》1999,274(32):22635-22645
The present studies compared caspase activation under cell-free conditions in vitro and in etoposide-treated HL-60 leukemia cells in situ. Immunoblotting revealed that incubation of HL-60 cytosol at 30 degrees C in the presence of cytochrome c and ATP (or dATP) resulted in activation of procaspases-3, -6, and -7 but not -2 and -8. Although similar selectivity was observed in intact cells, affinity labeling revealed that the active caspase species generated in vitro and in situ differed in charge and abundance. ATP and dATP levels in intact HL-60 cells were higher than required for caspase activation in vitro and did not change before caspase activation in situ. Replacement of ATP with the poorly hydrolyzable analogs 5'-adenylyl methylenediphosphate, 5'-adenylyl imidodiphosphate, or 5'-adenylyl-O-(3-thiotriphos-phate) slowed caspase activation in vitro, suggesting that ATP hydrolysis is required. Caspase activation in vitro was insensitive to phosphatase and kinase inhibitors (okadaic acid, staurosporine, and genistein) but was inhibited by Zn(2+), aurintricarboxylic acid, and various protease inhibitors, including 3,4-dichloroisocoumarin, N(alpha)-p-tosyl-L-phenylalanine chloromethyl ketone, N(alpha)-p-tosyl-L-lysine chloromethyl ketone, and N-(N(alpha)-benzyloxycarbonylphenylalanyl)alanine fluoromethyl ketone, each of which inhibited recombinant caspases-3, -6, -7, and -9. Experiments with anti-neoepitope antiserum confirmed that these agents inhibited caspase-9 activation. Collectively, these results suggest that caspase-9 activation requires nucleotide hydrolysis and is inhibited by agents previously thought to affect apoptosis by other means. 相似文献
165.
本文发表辽宁西部1新种, 即北栗山楂Crataegus beipiaogensis Tung et X.J.Tian;2新变种, 即球序绒毛胡枝子Lespedeza tomentosa Sieb.var.globiraccmi Tung et Lu.黄花阴山胡枝子Lespedeza inschanica(Maxim.)Schindl.var.flava Tung et Lu;2新变型, 即短序牛枝子Lespedeza potaninii Vassil f.brcviracemi Tung er Lu垂枝胡枝子Lespedeza bicolor Turcz f, pendunla Tunget Lu. 相似文献
166.
167.
Using hygromycin B resistance as a marker for selection, we have established the conditions required for the transformation
of Chlorella vulgaris. The exponentially grown C. vulgaris cells were transformed by electroporation with plasmid pIG121-Hm, and transformants were selected with hygromycin B at a
concentration of 50 μg/ml. Cell extracts prepared from the late-log cultures of the transformants exhibited glucuronidase
activities as conferred by the gus gene on pIG121-Hm. The maintenance of plasmid in the algal cells seemed to be transient as many cultures derived from the
hygromycin B-resistant colonies gradually lost the hygromycin resistance upon prolonged growth. The result of Southern blotting
of the genomic DNAs prepared from transformant cultures exhibiting persistent hygromycin resistance showed that integration
of part of the plasmid DNA into the host chromosome had taken place.
Received: 19 December 1997 / Revision received: 5 October 1998 / Accepted: 27 October 1998 相似文献
168.
Lucas R Lopes Vitor AR Miranda Rodrigo A Goes Gabriel GA Souza Giuliana R Souza Jessica CS Rocha Victor RA Cossich Jamila A Perini 《Biology of sport / Institute of Sport》2021,38(4):703
The COVID-19 pandemic has presented significant challenges and implications for the sports community. Thus, this study aimed to describe the prevalence of COVID-19 in Brazilian athletes and identify the epidemiological, clinical, athletic, life and health factors associated with the disease in these individuals. A cross-sectional study was performed involving 414 athletes from 22 different sports using an online questionnaire from August to November 2020. The association between the athletes’ characteristics and COVID-19 was evaluated using a logistic regression model. The prevalence of COVID-19 was 8.5%, although only 40% of athletes reported having been tested. Being under 27 years of age (3-fold), having children (~5-fold), having a teammate test positive for COVID-19 (2.5-fold), and smoking (14-fold) were associated with a possible higher risk of disease. Almost 20% of athletes self-reported musculoskeletal injuries during the period of the pandemic that was studied. Athletes with a university education (P = 0.02), a profession other than sports (P < 0.001), those from a low-income family (P = 0.01), and public health system users (P = 0.04) were significantly less frequently tested for COVID-19, whereas international competitors, athletes who received a wage, and athletes who had a teammate who tested positive for COVID-19 were 2-, 3-, and 15-fold more likely to be tested for COVID-19, respectively. Approximately 26% of the athletes who tested negative or were untested reported more than three characteristic COVID-19 symptoms, and 11% of athletes who tested positive for COVID-19 were asymptomatic. The identification of modifiable (have children, smoking, and teammates positively tested) and non-modifiable (age under 27 years) factors related to COVID-19 in athletes can contribute to implementing surveillance programmes to decrease the incidence of COVID-19 in athletes and its negative impacts in sports. 相似文献
169.
A proteomics approach to identifying novel protein targets involved in erinacine A–mediated inhibition of colorectal cancer cells’ aggressiveness 下载免费PDF全文
Ko‐Chao Lee Hsing‐Chun Kuo Chien‐Heng Shen Chien‐Chang Lu Wen‐Shih Huang Meng‐Chiao Hsieh Cheng‐Yi Huang Yi‐Hung Kuo Yung‐Yu Hsieh Chih‐Chuan Teng Li‐Ya Lee Shui‐Yi Tung 《Journal of cellular and molecular medicine》2017,21(3):588-599
Erinacine A, a major active component of a diterpenoid derivative isolated from Hericium erinaceus mycelium, has been demonstrated to exert anticancer effects. Herein, we present an investigation of the molecular mechanism of erinacine A induction associated with cancer cells’ aggressive status and death. A proteomic approach was used to purify and identify the differentially expressed proteins following erinacine A treatment and the mechanism of its action in apoptotic and the targets of erinacine A. Our results demonstrate that erinacine A treatment of HCT‐116 and DLD‐1 cells increased cell cytotoxicity and reactive oxygen species (ROS) production as well as decreased cell proliferation and invasiveness. Ten differentially displayed proteins were determined and validated in vitro and in vivo between the erinacine A‐treated and untreated groups. In addition, erinacine A time‐dependent induction of cell death and inhibitory invasiveness was associated with sustained phosphorylation of the PI3K/mTOR/p70S6K and ROCK1/LIMK2/Cofilin pathways. Furthermore, we demonstrated that erinacine A–induced HCT‐116 and DLD‐1 cells viability and anti‐invasion properties by up‐regulating the activation of PI3K/mTOR/p70S6K and production of ROS. Experiments involving specific inhibitors demonstrated that the differential expression of cofilin‐1 (COFL1) and profilin‐1 (PROF1) during erinacine A treatment could be involved in the mechanisms of HCT‐116 and DLD‐1 cells death and decreased aggressiveness, which occurred via ROCK1/LIMK2/Cofilin expression, with activation of the PI3K/mTOR/p70S6K signalling pathway. These findings elucidate the mechanism of erinacine A inhibiting the aggressive status of cells by activating PI3K/mTOR/p70S6K downstream signalling and the novel protein targets COF1 and PROF1; this could be a good molecular strategy to limit the aggressiveness of CRC cells. 相似文献
170.
Redox Flow Batteries: Annulated Dialkoxybenzenes as Catholyte Materials for Non‐aqueous Redox Flow Batteries: Achieving High Chemical Stability through Bicyclic Substitution (Adv. Energy Mater. 21/2017) 下载免费PDF全文