排序方式: 共有34条查询结果,搜索用时 15 毫秒
11.
Jose A. Chavez M. Mobin Siddique Siew Tein Wang Jianhong Ching James A. Shayman Scott A. Summers 《The Journal of biological chemistry》2014,289(2):723-734
Inhibitors of sphingolipid synthesis protect mice from diet induced-insulin resistance, and sphingolipids such as ceramides and glucosylated-ceramides (e.g., GM3) are putative nutritional intermediates linking obesity to diabetes risk. Herein we investigated the role of each of these sphingolipids in muscle and adipose tissue and conclude that they are independent and separable antagonists of insulin signaling. Of particular note, ceramides antagonize insulin signaling in both myotubes and adipocytes, whereas glucosyceramides are only efficacious in adipocytes: 1) In myotubes exposed to saturated fats, inhibitors of enzymes required for ceramide synthesis enhance insulin signaling, but those targeting glucosylceramide synthase have no effect. 2) Exogenous ceramides antagonize insulin signaling in myotubes, whereas ganglioside precursors do not. 3) Overexpression of glucosylceramide synthase in myotubes induces glucosylceramide but enhances insulin signaling. In contrast, glucosylated ceramides have profound effects in adipocytes. For example, either ganglioside addition or human glucosylceramide synthase overexpression suppresses insulin signaling in adipocytes. These data have important mechanistic implications for understanding how these sphingolipids contribute to energy sensing and the disruption of anabolism under conditions of nutrient oversupply. 相似文献
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M. Rai A.P. Ingle P. Ingle I. Gupta M. Mobin A. Bonifaz M. Alves 《Journal of applied microbiology》2021,131(4):1652-1667
Dematiaceous hyphomycetes (DH) are darkly pigmented fungi ubiquitously found all over the world as plant pathogens and saprophytes, and many of the members of this group have emerged as opportunistic pathogens. These fungi are responsible for a wide variety of infections including mycotic keratitis, which is considered as one of the major causes of corneal blindness, particularly in tropical and subtropical countries with an annual global burden of about 1 000 000 patients. The infection is more common in workers working in an outdoor environment. Moreover, trauma is found to be the most important predisposing cause of mycotic keratitis. Considerable delay in diagnosis and scarcity of effective pharmacological drugs are the major factors responsible for increased morbidity and visual impairment. Considering the crucial role of DH in mycotic keratitis, in the present review, we have focused on major DH with special emphasis on their pathogenicity, diagnosis and treatment strategies. 相似文献
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Mohan R Rastogi N Namboothiri IN Mobin SM Panda D 《Bioorganic & medicinal chemistry》2006,14(23):8073-8085
The Morita-Baylis-Hillman (MBH) type reaction of a variety of aromatic and heteroaromatic conjugated nitroalkenes with formaldehyde in the presence of stoichiometric amounts of imidazole and catalytic amounts (10 mol %) of anthranilic acid at room temperature provided the corresponding hydroxymethylated derivatives in moderate to good yield. The parent nitroalkenes and their MBH adducts were subsequently screened for their anticancer activity. Some of the MBH adducts were found to inhibit cervical cancer (HeLa) cell proliferation at low micromolar concentrations with half-maximal inhibitory concentrations in the range of 1-2 microM. The antiproliferative activity of 3-((E)-2-nitrovinyl)furan and three potent MBH adducts, namely, hydroxymethylated derivatives of 3-((E)-2-nitrovinyl)thiophene, 1-methoxy-4-((E)-2-nitrovinyl)benzene, and 1,2-dimethoxy-4-((E)-2-nitrovinyl)benzene was correlated well with their antimicrotubule activity. At their effective concentration range, the tested compounds perturbed the organization of mitotic spindle microtubules and chromosomes. In the presence of hydroxymethylated nitroalkenes, abnormal bipolar or multipolar mitotic spindles were apparent. Interphase microtubules were found to be significantly depolymerized at relatively higher concentrations of the tested compounds. These compounds inhibited tubulin assembly into microtubules in vitro by binding to tubulin at a site distinct from the vinblastine and colchicine binding sites. The compounds reduced the intrinsic tryptophan fluorescence of tubulin and the fluorescence of tubulin-1-anilinonaphthalene-8-sulfonic acid (ANS) complex indicating that they induced conformational changes in the tubulin. The results suggest that hydroxymethylated nitroalkenes exert their antiproliferative activity at least in part by depolymerizing cellular microtubules through tubulin binding and indicate that hydroxymethylated nitroalkenes are promising lead compounds for cancer therapy. 相似文献
15.
Yeo-Joong Yoon Mohammad Mobin Eun-Joo Hahn Kee-Yoeup Paek 《Environmental and Experimental Botany》2009,65(2-3):183-188
We assessed the effect of growth at either 400 μmol mol?1 (ambient) or 1000 μmol mol?1 (elevated) CO2 and 0 g L?1 (deprivation) or 30 g L?1 (supplementation) sugar on morphological traits, photosynthetic attributes and intrinsic elements of the CAM pathway using the CAM orchid Phalaenopsis ‘Amaglade’. The growth of shoot (retarded) and root (induced) was differently affected by CO2 enrichment and mixotrophic regime (+sugar). The Fv/Fm ratio was 14% more in CO2-enriched treatment than at ambient level during in vitro growth. At elevated level of CO2 and sugar treatment, the content of Chl(a + b), Chl a/b and Chl/Car was enhanced while carotenoid content remained unaltered. During in vitro growth, gas-exchange analysis indicated that increased uptake of CO2 accorded with the increased rate of transpiration and unchanged stomatal conductance at elevated level of CO2 under both photo- and mixotrophic growth condition. At elevated level of CO2 and sugar deprivation, activities of Rubisco (26.4%) and PEPC (74.5%) was up-regulated. Among metabolites, the content of sucrose and starch was always higher under CO2 enrichment during both in vitro and ex vitro growth. Our results indicate that plantlets grown under CO2 enrichment developed completely viable photosynthetic apparatus ready to be efficiently transferred to ex vitro condition that has far-reaching implications in micropropagation of Phalaenopsis. 相似文献
16.
An experiment was conducted under controlled conditions, in which grains of wheat (Triticum aestivum L. cv. Raj-3077) were soaked in 0, 1, 3 and 5 μM aqueous solutions of 28-homobrassinolide (HBR) for 4, 8 and 12 hours. The
seedlings raised from the grains pre-treated with HBR possessed significantly higher leaf number, fresh and dry weight·plant−1, nitrate reductase (NR,E.C. 1.6.6.1) and carbonic anhydrase (CA, E.C. 4.2.1.1) activities on 25 and 35 days, after sowing.
The soaking of the grains in 3 μM concentration for 8 or 12 hours produced the most vigorous seedlings. 相似文献
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Biomimetic sensor for certain catecholamines employing copper(II) complex and silver nanoparticle modified glassy carbon paste electrode 总被引:1,自引:0,他引:1
BJ Sanghavi SM Mobin P Mathur GK Lahiri AK Srivastava 《Biosensors & bioelectronics》2013,39(1):124-132
A dimeric Cu(II) complex [Cu(μ(2)-hep)(hep-H)](2)·2ClO(4) (1) containing bidentate (hep-H=2-(2-hydroxyethyl)pyridine) ligand was synthesized and characterized by single crystal X-ray diffraction studies. Each Cu-ion in 1 is in a distorted square pyramidal geometry. Further 1 along with silver nanoparticles (SNPs) have been used as modifier in the construction of a biomimetic sensor (1-SNP-GCPE) for determining certain catecholamines viz., dopamine (DA), levodopa (l-Dopa), epinephrine (EP) and norepinephrine (NE) using cyclic voltammetry, chronocoulometry, electrochemical impedance spectroscopy and adsorptive stripping square wave voltammetry (AdSSWV). Finally, the catalytic properties of the sensor were characterized by chronoamperometry. Employing AdSSWV, the calibration curves showed linear response ranging between 10(-6) and 10(-9)M for all the four analytes with detection limits (S/N=3) of 8.52×10(-10)M, 2.41×10(-9)M, 3.96×10(-10)M and 3.54×10(-10)M for DA, l-Dopa, EP and NE respectively. The lifetime of the biomimetic sensor was 3 months at room temperature. The prepared modified electrode shows several advantages such as simple preparation method, high sensitivity, high stability, ease of preparation and regeneration of the electrode surface by simple polishing along with excellent reproducibility. The method has been applied for the selective and precise analysis of DA, l-Dopa, EP and NE in pharmaceutical formulations, urine and blood serum samples. 相似文献
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The ruthenium-nitrosyl complexes [RuII(trpy)(tmp)(NO+)](ClO4)3 ([4](ClO4)3) and [RuII(trpy)(tmp)(NO)](ClO4)2 ([5](ClO4)2) with {Ru-NO}6 and {Ru-NO}7 configurations, respectively (trpy = 2,2′:6′,2′′-terpyridine, tmp = 3,4,7,8-tetramethyl-1,10-phenanthroline) have been isotaled. The nitrosyl complexes [4]3+ and [5]2+ have been generated by following a stepwise synthetic procedure: [RuII(trpy)(tmp)(X)]n, X/n = Cl/+ (1+) → CH3CN/2+ (22+) → NO2/+ (3+) → NO+/3+ (43+) → NO/2+ (52+). The single-crystal X-ray structures of two precursor complexes [1]ClO4 and [3]ClO4 have been determined. The DFT optimized structures of 43+ and 52+ suggest that the Ru-N-O geometries in the complexes are linear (177.9°) and bent (141.4°), respectively. The nitrosyl complexes with linear (43+) and bent (52+) geometries exhibit ν(NO) frequencies at 1935 cm−1 (DFT: 1993 cm−1) and 1635 cm−1 (DFT: 1684 cm−1), respectively. Complex 43+ undergoes two successive reductions at 0.25 V (reversible) and −0.48 V (irreversible) versus SCE involving the redox active NO function, RuII-NO+ ? RuII-NO and RuII-NO → RuII-NO−, respectively, besides the reductions of trpy and tmp at more negative potentials. The DFT calculations on the optimized 43+ suggest that LUMO and LUMO+1 are dominated by NO+ based orbitals of around 65% contribution along with partial metal contribution of ∼25% due to (dπ)RuII → π∗(NO+) back-bonding. The lowest energy transitions in 43+ and 52+ at 360 nm and 467 nm in CH3CN (TD-DFT: 364 and 459 nm) have been attributed to mixed MLLCT transitions of tmp(π) → NO+(π∗), Ru(dπ)/tmp(π) → NO+(π∗) and Ru(dπ)/NO(π) → trpy(π∗), respectively. The paramagnetic reduced species 52+ exhibits an anisotropic EPR spectrum with g1 = 2.018, g2 = 1.994, g3 = 1.880 (〈g〉 = 1.965 and Δg = 0.138) in CH3CN, along with 14N (I = 1) hyperfine coupling constant, A2 = 35 G at 110 K due to partial metal contribution in the singly occupied molecular orbital (DFT:SOMO:Ru (34%) and NO (53%)). Consequently, Mulliken spin distributions in 52+ are calculated as 0.115 for Ru and 0.855 for NO (N, 0.527; O, 0.328). The reaction of moderately electrophilic nitrosyl center in 43+ with the nucleophile, OH− yields the nitro precursor, 3+ with the second-order rate constant value of 1.7 × 10−1 M−1 s−1 at 298 K in CH3CN-H2O (10:1). On exposure to light (Xenon 350 W lamp) both the nitrosyl species, 43+ ({RuII-NO+}) and 52+ ({RuII-NO}) undergo photolytic Ru-NO bond cleavage process but with a widely varying kNO, s−1 (t1/2, s) of 1.56 × 10−1(4.4) and 0.011 × 10−1(630), respectively. 相似文献
19.
Andalib Sina Mashhadi-Mousapour Mobin Bijani Soroush Hosseini Mir-Jamal 《Neurochemical research》2019,44(5):1182-1191
Neurochemical Research - Coenzyme Q10 (CoQ10) is a natural compound, is involved in the mitochondrial electron transfer chain (ETC) and plays an important pattern in adenosine triphosphate (ATP)... 相似文献
20.
The ruthenium-iminoquinone complexes, [Ru(tpm)(Cl)(Q)]+ [tpm = tris(1-pyrazolyl)methane, Q = 3,5-di-tert-butyl-N-aryl-1,2-benzoquinonemonoimine, where aryl = C6H5, [1]+; m-(OCH3)2C6H3, [2]+; m-(Cl)2C6H3, [3]+] have been synthesized. The sensitive bond distances of “Q” in [1](ClO4) and [2](ClO4), C-O: 1.294(8), 1.281(2) Å; C-N: 1.352(8), 1.335(2) Å; and C-C(meta): 1.366(10)/1.367(9) Å, 1.364(2)/1.353(2) Å, respectively, and other analytical as well as theoretical (DFT) events suggest the valence configuration of [RuIII(tpm)(Cl)(QSq−)]+ for [1]+-[3]+. The paramagnetic [1]+-[3]+ show sharp 1H NMR spectra with strikingly small J of 1.8-3.0 Hz. The DFT calculations on [1]+ predict that the triplet (S = 1) state exists above (1004 cm−1) the singlet (S = 0) ground state. [1]+ exhibits μ = 2.2 BM at 300 K which diminishes to 0.3 BM near 2 K due to the steady decrease in the ratio of triplet to singlet population with the lowering of temperature. [1]+-[3]+ exhibit one oxidation and two successive reductions each in CH3CN. Experimental and DFT analyses collectively establish the valence configurations at the non-innocent {Ru-Q} interface along the redox chain as [(tpm)(Cl)RuIII(QQo)]2+ ([1]2+-[3]2+) → [(tpm)(Cl)RuIII(QSq−)]+ ([1]+-[3]+) → [(tpm)(Cl)RuII(QSq−)] ↔ [(tpm)(Cl)RuIII(QCat)] (1-3) → [(tpm)(Cl)RuII(QCat)]− ([1]−-[3]−). The spectral features of [1]n-[3]n (n = +2, +1, 0) have been addressed based on the TD-DFT calculations on [1]n. 相似文献