排序方式: 共有227条查询结果,搜索用时 343 毫秒
21.
Konrad S Ali SR Wiege K Syed SN Engling L Piekorz RP Hirsch E Nürnberg B Schmidt RE Gessner JE 《The Journal of biological chemistry》2008,283(48):33296-33303
Fcgamma receptors (FcgammaR) and the C5a receptor (C5aR) are key effectors of the acute inflammatory response to IgG immune complexes (IC). Their coordinated activation is critical in IC-induced diseases, although the significance of combined signaling by these two different receptor classes in tissue injury is unclear. Here we used the mouse model of the passive reverse lung Arthus reaction to define their requirements for distinct phosphoinositide 3-kinase (PI3K) activities in vivo. We show that genetic deletion of class IB PI3Kgamma abrogates C5aR signaling that is crucial for FcgammaR-mediated activation of lung macrophages. Thus, in PI3Kgamma(-/-) mice, IgG IC-induced FcgammaR regulation, cytokine release, and neutrophil recruitment were blunted. Notably, however, C5a production occurred normally in PI3Kgamma(-/-) mice but was impaired in PI3Kdelta(-/-) mice. Consequently, class IA PI3Kdelta deficiency caused resistance to acute IC lung injury. These results demonstrate that PI3Kgamma and PI3Kdelta coordinate the inflammatory effects of C5aR and FcgammaR and define PI3Kdelta as a novel and essential element of FcgammaR signaling in the generation of C5a in IC disease. 相似文献
22.
Munir S Jiang B Guilcher A Brett S Redwood S Marber M Chowienczyk P 《American journal of physiology. Heart and circulatory physiology》2008,294(4):H1645-H1650
Exercise markedly influences pulse wave morphology, but the mechanism is unknown. We investigated whether effects of exercise on the arterial pulse result from alterations in stroke volume or pulse wave velocity (PWV)/large artery stiffness or reduction of pressure wave reflection. Healthy subjects (n = 25) performed bicycle ergometry. with workload increasing from 25 to 150 W for 12 min. Digital arterial pressure waveforms were recorded using a servo-controlled finger cuff. Radial arterial pressure waveforms and carotid-femoral PWV were determined by applanation tonometry. Stroke volume was measured by echocardiography, and brachial and femoral artery blood flows and diameters were measured by ultrasound. Digital waveforms were recorded continuously. Other measurements were made before and after exercise. Exercise markedly reduced late systolic and diastolic augmentation of the peripheral pressure pulse. At 15 min into recovery, stroke volume and PWV were similar to baseline values, but changes in pulse wave morphology persisted. Late systolic augmentation index (radial pulse) was reduced from 54 +/- 3.9% at baseline to 42 +/- 3.7% (P < 0.01), and diastolic augmentation index (radial pulse) was reduced from 37 +/- 1.8% to 25 +/- 2.9% (P < 0.001). These changes were accompanied by an increase in femoral blood flow (from 409 +/- 44 to 773 +/- 48 ml/min, P < 0.05) and an increase in femoral artery diameter (from 8.2 +/- 0.4 to 8.6 +/- 0.4 mm, P < 0.05). In conclusion, exercise dilates muscular arteries and reduces arterial pressure augmentation, an effect that will enhance ventricular-vascular coupling and reduce load on the left ventricle. 相似文献
23.
T. Khan M. Zahid M. Asim Shahzad ul-Hussan Z. Iqbal M. Iqbal Choudhary V. Uddin Ahmad 《Phytomedicine》2002,9(8):749-752
The crude acetone extract of aerial parts of Salvia moorcraftiana Wall. was screened for various biological activities including Lemna bioassay, antifungal, antibacterial, leishmanicidal, insecticidal activities and brine shrimp cytotoxicity. It was found to possess strong phytotoxic activity against Lemna aequinoctials Welve. and moderate antifungal activity against animal and plant pathogens. The purified chemical constituents were tested for enzyme inhibition activity. Two constituents (compounds 3 and 8) were found to be effective inhibitors of alpha-glucosidase. 相似文献
24.
Khuram Shahzad Abdul Hai Nadeem Kizilbash Jawaria Ambreen Jamal Alruwaili 《Bioinformation》2013,9(9):471-476
DNA γ is approximately half of the size of Begomovirus DNA. It encodes a γC1 gene that is conserved in position and size. This
gene has the capacity to encode a 13 to 14 kDa protein comprising 118 amino acid residues. It has been shown earlier that γC1
protein is necessary for inducing symptoms of cotton leaf curl disease. The structure for γC1 (CLCuDγ01-Pakistan) is still
unknown. Therefore, a model of γC1 (CLCuDγ01-Pakistan) was developed using DoBo and I-TASSER servers followed by
validation by PROCHECK and VERIFY 3D servers. The developed model provides an insight in a role for this multifunctional
protein in causing Cotton Leaf Curl Disease (CLCuD). A possible function of this protein might be the suppression of RNAsilencing
in cotton plants. 相似文献
25.
Muhammad Masroor Alam Adnan Khurshid Shahzad Shaukat Muhammad Suleman Rana Salmaan Sharif Mehar Angez Nadia Nisar Muhammad Naeem Syed Sohail Zahoor Zaidi 《PloS one》2013,8(11)
Human parechoviruses are known to cause asymptomatic to severe clinical illness predominantly respiratory and gastroenetric infections. Despite their global prevalence, epidemiological studies have not been performed in Pakistan. In this study, we retrospectively analyzed 110 fecal specimen and found 26 (24%) positive for viral RNA with HPeV-10 (n = 3, 23%), HPeV-13 (n = 4, 31%) and HPeV-15 (n = 6, 46%) genotypes. Clinical features of patients with different HPeV genotypes were compared. All HPeV positive children were aged ≤4 years (mean 13.92 months). The male-to-female ratio was 1: 1.17 (46.2 vs 53.8%) with significant association (p = .031) to HPeV infectivity. HPeV-10 and -13 were found during summer while HPeV-15 was only detected during late winter season. Disease symptoms were more severe in children infected with HPeV-10 and -13 as compared to HPeV-15. Fever and vomiting were observed in 100% cases of HPeV-10 and -13 while only 17% patients of HPeV-15 had these complaints. Phylogenetic analyses showed that HPeV-10, -13 and -15 strains found in this study have 9–13%, 16.8% and 21.8% nucleotide divergence respectively from the prototype strains and were clustered to distinct genetic lineages. This is the first report of HPeV-15 infection in humans although first identified in rhesus macaques. The arginine-glycine-aspartic acid (RGD) motif present at the C-terminal of VP1 responsible for the viral attachment to cellular integrins was not found in all of these strains. In conclusion, these findings enhance our knowledge related to the epidemiology and genetic diversity of the HPeV in Pakistan and support the need for continued laboratory based surveillance programs especially in infants and neonatal clinical settings. Further, the parechovirus pathogenesis, cross-species transmission and disease reservoirs must be ascertained to adopt better prevention measures. 相似文献
26.
Khuram Shahzad Ahmad 《Soil & Sediment Contamination》2018,27(4):249-266
Alachlor, a globally used aniline herbicide, has great agronomic interest for controlling the development of broadleaved weeds and grasses. This research aspires to evaluate the sorption attributes of Alachlor through batch equilibrium method and its successive removal through biomass based activated carbon prepared from Sawdust (Cedrus deodara). Six soil samples were collected from selected regions of Pakistan to assess the adsorption and removal phenomena. Adsorption capacity for Alachlor varied in soils depending upon their physicochemical properties. Adsorption coefficient (Kd) values ranged from 12 to 31 µg ml?1 with the highest Kd value observed in soil sample with highest organic content (1.4%) and least pH (5.62). The Gibbs free energy values ranged from ?17 to ?20 kJ mol?1 proposing physio-sorption and exothermic interaction with soils. Values of R2 (0.96–0.99) exhibited the best fit to linear adsorption model. Adsorption coefficient displayed a negative correlation (r = ?0.97) with soil pH and positive correlation with organic matter (r = 0.87). The effect of contact time and pesticide concentration on the removal efficiency by activated carbon was investigated. The highest removal percentages observed through activated carbon were 66% and 64% at concentrations of 5 and 7.5 ppm respectively. Activated carbon from sawdust (Cedrus deodara) was investigated as a suitable adsorbent for the removal of Alachor from selected soils. Biomass based activated carbon can prove to be an effective and a sustainable mean to remove pesticides from soil. 相似文献
27.
Catalytic power of enzymes decreases with temperature: New insights for understanding soil C cycling and microbial ecology under warming
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Gaël Alvarez Tanvir Shahzad Laurence Andanson Michael Bahn Matthew D. Wallenstein Sébastien Fontaine 《Global Change Biology》2018,24(9):4238-4250
Most current models of soil C dynamics predict that climate warming will accelerate soil C mineralization, resulting in a long‐term CO2 release and positive feedback to global warming. However, ecosystem warming experiments show that CO2 loss from warmed soils declines to control levels within a few years. Here, we explore the temperature dependence of enzymatic conversion of polymerized soil organic C (SOC) into assimilable compounds, which is presumed the rate‐limiting step of SOC mineralization. Combining literature review, modelling and enzyme assays, we studied the effect of temperature on activity of enzymes considering their thermal inactivation and catalytic activity. We defined the catalytic power of enzymes (Epower) as the cumulative amount of degraded substrate by one unit of enzyme until its complete inactivation. We show a universal pattern of enzyme's thermodynamic properties: activation energy of catalytic activity (EAcat) < activation energy of thermal inactivation (EAinact). By investing in stable enzymes (high EAinact) having high catalytic activity (low EAcat), microorganisms may maximize the Epower of their enzymes. The counterpart of such EAs’ hierarchical pattern is the higher relative temperature sensitivity of enzyme inactivation than catalysis, resulting in a reduction in Epower under warming. Our findings could explain the decrease with temperature in soil enzyme pools, microbial biomass (MB) and carbon use efficiency (CUE) reported in some warming experiments and studies monitoring the seasonal variation in soil enzymes. They also suggest that a decrease in soil enzyme pools due to their faster inactivation under warming contributes to the observed attenuation of warming effect on soil C mineralization. This testable theory predicts that the ultimate response of SOC degradation to warming can be positive or negative depending on the relative temperature response of Epower and microbial production of enzymes. 相似文献
28.
Arabidopsis HIPP27 is a host susceptibility gene for the beet cyst nematode Heterodera schachtii 总被引:1,自引:0,他引:1
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Zoran S. Radakovic Muhammad Shahzad Anjam Elizabeth Escobar Divykriti Chopra Javier Cabrera Ana Cláudia Silva Carolina Escobar Miroslaw Sobczak Florian M. W. Grundler Shahid Siddique 《Molecular Plant Pathology》2018,19(8):1917-1928
Sedentary plant‐parasitic cyst nematodes are obligate biotrophs that infect the roots of their host plant. Their parasitism is based on the modification of root cells to form a hypermetabolic syncytium from which the nematodes draw their nutrients. The aim of this study was to identify nematode susceptibility genes in Arabidopsis thaliana and to characterize their roles in supporting the parasitism of Heterodera schachtii. By selecting genes that were most strongly upregulated in response to cyst nematode infection, we identified HIPP27 (HEAVY METAL‐ASSOCIATED ISOPRENYLATED PLANT PROTEIN 27) as a host susceptibility factor required for beet cyst nematode infection and development. Detailed expression analysis revealed that HIPP27 is a cytoplasmic protein and that HIPP27 is strongly expressed in leaves, young roots and nematode‐induced syncytia. Loss‐of‐function Arabidopsis hipp27 mutants exhibited severely reduced susceptibility to H. schachtii and abnormal starch accumulation in syncytial and peridermal plastids. Our results suggest that HIPP27 is a susceptibility gene in Arabidopsis whose loss of function reduces plant susceptibility to cyst nematode infection without increasing the susceptibility to other pathogens or negatively affecting the plant phenotype. 相似文献
29.