排序方式: 共有170条查询结果,搜索用时 15 毫秒
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Although strontium (Sr2+) is found in soils, sediments and surface waters, there is limited evidence about its biosorption. In this study, a surface water strain being highly tolerant to Sr2+ was isolated and identified as Micrococcus luteus Sr02 by using 16S rRNA sequencing. Biosorption behavior and mechanisms of Sr2+ by M. luteus Sr02 were investigated through batch experiments, zeta potential measurements, Fourier transform infrared spectroscopy and scanning electron microscopy. The results showed that M. luteus Sr02 have potential to sorb Sr2+ and can be used efficiently for the removal of Sr2+ from aqueous solutions. 相似文献
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Kiziler AR Aydemir B Onaran I Alici B Ozkara H Gulyasar T Akyolcu MC 《Biological trace element research》2007,120(1-3):82-91
We measured the levels of malondialdehyde (MDA), protein carbonyls, glutathione S-transferase (GST) and reducte glutathione (GSH) in seminal plasma and spermatozoa from 95 subjects including 50 infertile
patients to evaluate the association between oxidative stress and damage and the components of the anti-oxidant defenses in
seminal plasma and spermatozoa of infertile subjects and concentrations of cadmium (Cd) and lead (Pb) in the blood and seminal
plasma because of tobacco smoke exposure. The reactive oxygen species (ROS) in spermatozoa were also evaluated by luminol
(5-amino-2,3-dihydro-1,4-phthalazinedione)-enhanced chemiluminescence assay. The sperm count, motility, and morphology in
the smokers infertile group were found to be lower than those in the fertile male group and nonsmokers infertile group (p < 0.001). Concentrations of Cd, Pb, MDA, protein carbonyls, and ROS levels in the smokers infertile group were significantly
higher than those in the fertile male and nonsmokers infertile male groups (p < 0.001). However, GSH levels and GST activities were decreased in the smokers infertile male group than those in the fertile
male and nonsmokers infertile male groups (p < 0.001). The results indicate that smoking could affect semen quality and oxidative lipid and protein damage in human spermatozoa.
From Pearson correlation analysis, positive correlations were demonstrated between the seminal plasma Cd and seminal plasma
protein carbonyls and between seminal plasma Pb and spermatozoa ROS levels in smokers of the subfertile group, while there
was a significant positive correlation between blood Cd and ROS levels in smokers of the fertile group. There was also a significant
negative correlation of the Cd level of the blood and GSH levels of the sperm and seminal plasma. These findings suggest that
cigarette smoking enhances the levels of Cd and Pb in seminal plasma and blood and the extent of oxidative damage associated
with a decrease in components of the anti-oxidant defenses in the sperm of infertile males. 相似文献
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Peroxynitrite and NO donors form colored nitrite adducts with sinapinic acid: potential applications
Shirin Akhter James R. Green Paul Root Gregory J. Thatcher Bulent Mutus 《Nitric oxide》2003,8(4):214-221
Sinapinic acid (3,5-dimethoxy-4-hydroxycinnamic acid, SA) reacted with peroxynitrous acid at neutral pH with a second-order rate constant of 812 M(-1)s(-1), to yield a red product (lambda(max), 532 nm). The identical colored product could be formed with acidified decomposed peroxynitrous acid solutions or nitrite at slower rates (0.1M HCl, 8.32 M(-1)s(-1); 10% acetic acid, 0.0004 M(-1)s(-1)). The red compound is thought to be O-nitrososinapinic acid (3,5-dimethoxy-4-nitrosooxycinnamic acid) which can be formed by reaction with either peroxynitrous acid or nitrous acid. The extinction coefficient of O-nitrososinapinic acid (ONSA) was estimated to be 8419 M(-1)cm(-1) at 510 nm in 10% acetic acid and 90% acetonitrile. ONSA was also formed via NO(+) transfer from S-nitrosoglutathione (GSNO). ONSA in turn can S-nitrosate low molecular weight thiols and protein thiols. SA was also shown to act as a peroxynitrite sink as it effectively prevented the oxidation of dihydrorhodamine under physiological conditions. The fact that O-nitrososinapinic acid is stable and can be used to S-nitrosate thiol containing amino acids, peptides, and proteins makes it a potentially useful reagent in the study of S-nitrosothiol biochemistry and physiology. In addition, the relatively high extinction coefficient of O-nitrososinapinic acid means that it could be utilized as an analyte for the spectroscopic detection of peroxynitrite or NO(+)-donors in the submicromolar range. 相似文献
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Irina Gorshkova Tong Zhou Biji Mathew Jeffrey R. Jacobson Daisuke Takekoshi Palash Bhattacharya Brett Smith Bulent Aydogan Ralph R. Weichselbaum Viswanathan Natarajan Joe G. N. Garcia Evgeny V. Berdyshev 《Journal of lipid research》2012,53(8):1553-1568
The enforcement of sphingosine-1-phosphate (S1P) signaling network protects from radiation-induced pneumonitis. We now demonstrate that, in contrast to early postirradiation period, late postirradiation sphingosine kinase-1 (SphK1) and sphingoid base-1-phosphates are associated with radiation-induced pulmonary fibrosis (RIF). Using the mouse model, we demonstrate that RIF is characterized by a marked upregulation of S1P and dihydrosphingosine-1-phosphate (DHS1P) levels in the lung tissue and in circulation accompanied by increased lung SphK1 expression and activity. Inhibition of sphingolipid de novo biosynthesis by targeting serine palmitoyltransferase (SPT) with myriocin reduced radiation-induced pulmonary inflammation and delayed the onset of RIF as evidenced by increased animal lifespan and decreased expression of markers of fibrogenesis, such as collagen and α-smooth muscle actin (α-SMA), in the lung. Long-term inhibition of SPT also decreased radiation-induced SphK activity in the lung and the levels of S1P-DHS1P in the lung tissue and in circulation. In vitro, inhibition or silencing of serine palmitoyltransferase attenuated transforming growth factor-β1 (TGF-β)-induced upregulation of α-SMA through the negative regulation of SphK1 expression in normal human lung fibroblasts. These data demonstrate a novel role for SPT in regulating TGF-β signaling and fibrogenesis that is linked to the regulation of SphK1 expression and S1P-DHS1P formation. 相似文献
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Intermedin/adrenomedullin-2 dilates the rat pulmonary vascular bed: dependence on CGRP receptors and nitric oxide release 总被引:21,自引:0,他引:21
Intermedin/adrenomedullin-2 (IMD/AM2) is a 47 amino acid peptide formed by enzymatic degradation of preprointermedin. The present study was undertaken to investigate the effects of rat IMD (rIMD) in the isolated buffer perfused rat lung (IBPR) under resting conditions and under conditions of elevated pulmonary vasoconstrictor tone (PVT). Under resting conditions in the IBPR, rIMD had little or no activity. When PVT was actively increased by infusion of U46619, bolus injection of IMD decreased pulmonary arterial pressure (PAP) in a dose-dependent manner. Since the pulmonary perfusion rate and left atrial pressure were constant, these reductions in PAP directly reflect reductions in pulmonary vascular resistance (PVR). The pulmonary vasodilator response to rIMD, when compared to calcitonin gene-related peptide (CGRP) on a molar basis, was greater at the lowest and midrange doses. The degree of inhibition by CGRP8-37 on pulmonary vasodilator response to rIMD was significantly less when compared to CGRP. Pretreatment with L-nitro-arginine-methyl ester (L-NAME), unlike meclofenamate and glybenclamide, significantly reduced the pulmonary vasodilator responses to rIMD. rIMD administration induced cross-tachyphylaxis to the pulmonary vasodilator response to CGRP whereas CGRP administration did not alter the ability of rIMD to dilate the IBPR. Pulmonary vasodilator responses to repeated injections of rIMD did not undergo tachyphylaxis. The present data demonstrate rIMD possesses direct vasodilator activity in the rat pulmonary vascular bed. The present data suggest activation of CGRP1 receptors and release of nitric oxide (NO*) mediate the pulmonary vasodilator response to rIMD whereas cyclooxygenase products and KATP channels do not contribute to the pulmonary vasodilator response to rIMD. The ability of rIMD to induce heterologous desensitization of CGRP1 receptor activation, to retain much of its pulmonary vasodilator activity after inhibition of CGRP1 receptors, and to lack homologous desensitization together suggests the pulmonary, unlike the systemic, vasodilator response to rIMD may depend on other vasodilator mechanisms including receptors in the calcitonin-receptor-like-receptor (CRLR) family. 相似文献
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Halil Ibrahim Secer Ilker Solmaz Ihsan Anik Yusuf Izci Bulent Duz Mehmet Kadri Daneyemez Engin Gonul 《Journal of brachial plexus and peripheral nerve injury》2009,4(1):1-10