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排序方式: 共有1031条查询结果,搜索用时 15 毫秒
91.
Sphingosine 1-phosphate (S1P), a bioactive sphingolipid involved in diverse biological processes, is generated by sphingosine kinase (SphK) and acts via intracellular and/or extracellular mechanisms. We used biochemical, pharmacological, and physiological approaches to investigate in rat myometrium the contractile effect of exogenous S1P and the possible contribution of SphK in endothelin-1 (ET-1)-mediated contraction. S1P stimulated uterine contractility (EC50 = 1 µM and maximal response = 5 µM) by a pertussis toxin-insensitive and a phospholipse C (PLC)-independent pathway. Phosphorylated FTY720, which interacts with all S1P receptors, except S1P2 receptors, failed to mimic S1P contractile response, indicating that the effects of S1P involved S1P2 receptors that are expressed in myometrium. Contraction mediated by S1P and ET-1 required extracellular calcium and Rho kinase activation. Inhibition of SphK reduced ET-1-mediated contraction. ET-1, via ETA receptors coupled to pertussis toxin-insensitive G proteins, stimulated SphK1 activity and induced its translocation to the membranes. Myometrial contraction triggered by ET-1 is consecutive to the sequential activation of PLC, protein kinase C, SphK1 and Rho kinase. Prolonged exposure of the myometrium to S1P downregulated S1P2 receptors and abolished the contraction induced by exogenous S1P. However, in these conditions, the tension triggered by ET-1 was not reduced, indicating that SphK activated by ET-1 contributed to its contractile effect via a S1P2 receptor-independent process. Our findings demonstrated that exogenous S1P and SphK activity regulated myometrial contraction and may be of physiological relevance in the regulation of uterine motility during gestation and parturition. uterus; contraction 相似文献
92.
Ali Amoozegar M Zahra Fatemi A Reza Karbalaei-Heidari H Reza Razavi M 《Microbiological research》2007,162(4):369-377
An extracellular protease was produced under stress conditions of high temperature and high salinity by a newly isolated moderate halophile, Salinivibrio sp. strain AF-2004 in a basal medium containing peptone, beef extract, glucose and NaCl. A modification of Kunitz method was used for protease assay. The isolate was capable of producing protease in the presence of sodium chloride, sodium sulfate, sodium nitrate, sodium nitrite, potassium chloride, sodium acetate and sodium citrate. The maximum protease was secreted in the presence of 7.5 to 10% (w/v) sodium sulfate or 3% (w/v) sodium acetate (4.6 U ml−1). Various carbon sources including glucose, lactose, casein and peptone were capable of inducing enzyme production. The optimum pH, temperature and aeration for enzyme production were 9.0, 32 °C and 220 rpm, respectively. The enzyme production corresponded with growth and reached a maximum level during the mid-stationary phase. Maximum protease activity was exhibited in the medium containing 1% (w/v) NaCl at 60 °C, with 18% and 41% activity reductions at temperature 50 and 70 °C, respectively. The optimum pH for enzyme activity was 8.5, with 86% and 75% residual activities at pH 10 and 6, respectively. The activity of enzyme was inhibited by EDTA. These results suggest that the protease secreted by Salinivibrio sp. strain AF-2004 is industrially important from the perspectives of its activity at a broad pH ranges (5.0–10.0), its moderate thermoactivity in addition to its high tolerance to a wide range of salt concentration (0–10% NaCl). 相似文献
93.
Heidari Reza Farajzadeh Sheikh Ahmad Hashemzadeh Mohammad Farshadzadeh Zahra Salmanzadeh Shokrollah Saki Morteza 《Molecular biology reports》2022,49(5):3811-3822
Molecular Biology Reports - This study was aimed to evaluate the antibiotic resistance, biofilm formation, and genetic diversity of carbapenem-resistant Pseudomonas aeruginosa (CRPA) strains... 相似文献
94.
BioMetals - Small molecules have potential usage in cancer therapy due to their remarkable potency of disarranging the natural structure of nucleic acids. In this study, two complexes... 相似文献
95.
96.
Root-knot nematodes (RKN) are the most serious plant parasitic nematodes having a broad host range exceeding 2,000 plant species. Quercus brantii Lindl. and Q. infectoria Oliv are the most important woody species of Zagros forests in west of Iran where favors sub-Mediterranean climate. National Botanical Garden of Iran (NBGI) is scheduled to be the basic center for research and education of botany in Iran. This garden, located in west of Tehran, was established in 1968 with an area of about 150 ha at altitude of 1,320 m. The Zagros collection has about 3-ha area and it has been designed for showing a small pattern of natural Zagros forests in west of Iran. Brant’s oak (Q. brantii) and oak manna tree (Q. infectoria) are the main woody species in Zagros collection, which have been planted in 1989. A nematological survey on Zagros forest collection in NBGI revealed heavily infection of 24-yr-old Q. brantii and Q. infectoria to RKN, Meloidogyne hapla. The roots contained prominent galls along with egg sac on the surface of each gall. The galls were relatively small and in some parts of root several galls were conjugated, and all galls contained large transparent egg masses. The identification of M. hapla was confirmed by morphological and morphometric characters and amplification of D2-D3 expansion segments of 28S rRNA gene. The obtained sequences of large-subunit rRNA gene from M. hapla was submitted to the GenBank database under the accession number . The sequence was compared with those of M. hapla deposited in GenBank using the BLAST homology search program and showed 99% similarity with those KP319025, KJ755183, GQ130139, and DQ328685. The second stage juveniles of M. hapla isolated from Brant’s oak (Q. Brantii) showed the following morphometric characters: (n = 12), L = 394 ± 39.3 (348 to 450) µm; a = 30.9 ± 4 (24.4 to 37.6); b = 4.6 ± 0.44 (4 to 5.1); b΄ = 3.3 ± 0.3 (2.7 to 3.7), c = 8.0 ± 1 (6.2 to 10.3), ć = 5.3 ± 0.8 (3.5 to 6.3); Stylet = 12.1 ± 0.8 (11 to 13) µm; Tail = 50 ± 5.6 (42 to 57) µm; Hyaline 15 ± 1.8 (12 to 18) µm. Oak manna, Q. infectoria population of second stage juveniles clearly possessed short body length and consequently other morphometric features were less than those determined for Q. brantii population, and these features were: (n = 12), L = 359.0 ± 17.3 (319 to 372) µm; a = 28.6 ± 3 (22.8 to 31); b = 5.0 ± 0.3 (4.8 to 5.2); b΄ = 3.3 ± 0.2 (3 to 3.6), c = 8.1 ± 0.5 (7.4 to 8.8), ć = 4.7 ± 0.5 (3.9 to 5.2); Stylet = 11.4 ± 0.7 (10 to 12) µm; Tail = 44 ± 1.8 (42 to 47) µm; Hyaline 12 ± 1.7 (10 to 15) µm. To date two species of Meloidogyne, M. querciana
KJ645428Golden, 1979 and M. christiei
Golden and Kaplan, 1986 have been reported to parasitize oaks (Quercus spp.) from the United States of America. M. querciana was found on pin oak Quercus palustris in Virginia. The oak RKN infected pine oak, red oak, and American chestnut heavily in greenhouse tests (Golden, 1979). The other species M. christiei was described from turkey oak and Q. laevis in Florida, which has monospecific host range (Golden and Kaplan, 1986). Both of these RKN species seem to be restricted to the United States of America and have not been reported from other place. According to our knowledge this is the first report of occurrence of M. hapla on Q. brantii and Q. infectoria in the world. This study includes these two oak species to the host range of RKN, M. hapla for the world and expands the information of RKN, M. hapla host ranges on oaks. 相似文献
97.
Hajibarat Zahra Saidi Abbas Hajibarat Zohreh Talebi Reza 《Physiology and Molecular Biology of Plants》2015,21(3):365-373
Physiology and Molecular Biology of Plants - To evaluate the genetic diversity among 48 genotypes of chickpea comprising cultivars, landraces and internationally developed improved lines genetic... 相似文献
98.
Zahra Zamani Masoud Bahar Marie Agnès Jacques Mohammad Reza Lak Alireza Akhavan 《World journal of microbiology & biotechnology》2011,27(10):2371-2378
Xanthomonad-like bacteria that are associated with common bacterial blight of bean in Iran were identified on the basis of
their colonial morphology, biochemical and serological properties, presence of a specific DNA fragment using PCR primers and
pathogenicity on bean. Xanthomonas axonopodis pv. phaseoli (Xap) strains were further characterized using rep-PCR and restriction fragment length polymorphism (RFLP). RFLP profiles
generated by the restriction endonucleases RsaI, TaqI, HaeIII and Sau96I and rep-PCR analysis revealed that Iranian strains were relatively genetically homogenous. The similarity coefficients
among the strains ranged from 0.87 to 1. The genetic diversity coefficients among strains from three infected provinces, Isfahan,
Markazi and Lorestan, were 0.019, 0.072 and 0.033, respectively. The low overall level of polymorphism within Xap isolates
collected from the three Iranian infected regions could suggest that few initial inoculum introductions might have distributed
among these different bean-growing areas in Iran. 相似文献
99.
Ali Behrad Vakylabad Mohammad Ranjbar Zahra ManafiFereshteh Bakhtiari 《International biodeterioration & biodegradation》2011,65(8):1208-1214
Bioleaching studies were conducted to evaluate the extraction of copper from combined flotation concentrate and smelter dust using two different dust-addition strategies, non-fractional (simultaneously with concentrate) and fractional (step-wise dust addition) in stirred tank reactors. The highest copper extraction obtained with the fractional dust addition was up to 94% while extraction using the non-fractional method leveled off at approximately 44%. Thus, an increased copper recovery of about 50% was achieved with the fractional dust-addition method. It seems that the main reason for increased copper recovery using fractional dust addition could be the control and prevention of chalcopyrite passivation (according to SEM/EDS, XRD, and quantitative mineralogy data). This leads to its improved dissolution. 相似文献
100.
Arezou Ghahghaei S. Zahra Bathaie Ali Shahraki Farzad Rahmany Asgarabad 《International journal of peptide research and therapeutics》2011,17(2):101-111
β-Casein is one of the major components of the milk micelles of most mammals and has been shown to exhibit in vitro chaperone-like
activity. Glycerol is a chemical chaperone belonging to the polyol family, which increases protein stability and inhibits
protein aggregation. These prompted us to compare the chaperone-like activity of β-casein and glycerol. In this study, the
effect of β-casein and glycerol on folding of the target proteins (ovotransferrin, insulin and α-lactalbumin) in the presence
of dextran, as a macromolecular crowding agent, is examined using visible absorption spectroscopy, intrinsic fluorescence
spectroscopy, 1-anilino-8-naphthalene sulfonic acid fluorescence binding and near CD spectroscopy. In the presence of dextran,
the rate and extent of aggregation of target proteins was enhanced and β-casein was less effective in preventing the aggregation
and precipitation of target proteins. These data support the hypothesis that β-casein interacts more effectively with slowly
aggregating rather than rapidly aggregating target proteins. It is proposed that dextran-induced changes to protein conformation
and the rate of intermolecular association are in a kinetic competition with the chaperoning action of β-casein; however our
results demonstrated the higher activity of glycerol, as a chemical chaperone, than β-casein on the folding of target proteins,
especially in the presence of dextran. This is likely due to the stabilizing effect of glycerol on protein structure and environment.
The implications for the in vivo functions of β-casein and glycerol, based on their exhibiting such in vitro chaperone-like
activities, are discussed. 相似文献