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91.
The study is aimed at exploring the utility of thermoanalytical methods in the solid-state characterization of various crystalline
forms of nevirapine. The different forms obtained by recrystallization of nevirapine from various solvents were identified
using differential scanning calorimetry and thermogravimetric analysis (TGA). The appearance of desolvation peak accompanied
by weight loss in TGA indicated the formation of solvates: hemi-ethanolate (Form I), hemi-acetonitrilate (Form II), hemi-chloroformate
(Form III), hemi-THF solvate (Form IV), mixed hemi-ethanolate hemi-hydrate (Form V), and hemi-toluenate (Form VI). The higher
desolvation temperatures of all the solvates except toluenate than their respective boiling point indicate tighter binding
of solvent. Emphasis has been laid on the determination of heat capacity and heat of solution utilizing microreaction calorimeter
to further distinguish the various forms. The enthalpy of solution (ΔH
sol), an indirect measure of the lattice energy of a solid, was well correlated with the crystallinity of all the solid forms
obtained. The magnitude of ΔH
sol was found to be −14.14 kJ/mol for Form I and −2.83 kJ/mol for Form V in phosphate buffer of pH 2, exhibiting maximum ease
of molecular release from the lattice in Form I. The heat capacity for solvation (ΔC
p) was found to be positive, providing information about the state of solvent molecules in the host lattice. The solubility
and dissolution rate of the forms were also found to be in agreement with their enthalpy of solution. Form (I), being the
most exothermic, was found to be the most soluble of all the forms. 相似文献
92.
Renu Bhardwaj Sukhbir Kaur Pramodh Kumar Nagar Hardesh Kumar Arora 《Plant Growth Regulation》2007,53(1):1-5
Brassinosteroids play an important role in growth and development of plants. They have been reported universally in all the
plants. The present study deals with the presence of these compounds in immature tea seeds. Five brassinosteroids, i.e. 6-deoxo-28-norcathasterone,
6-deoxo-28-norteasterone, 3-dehydro-6-deoxo-28-norteasterone, 6-deoxo-28-nortyphasterol and 6-deoxo-28-norcastasterone have
been isolated and identified by GC–MS. The identified brassinosteroids and their derivatives are active constituents of late
C-6 oxidation pathway, thereby suggesting the biosynthesis of brassinosteroids in tea seeds by late C-6 oxidation pathway. 相似文献
93.
Arora V Cheung HH Plenchette S Micali OC Liston P Korneluk RG 《The Journal of biological chemistry》2007,282(36):26202-26209
X-linked inhibitor of apoptosis (XIAP)-associated factor 1 (XAF1) is a putative tumor suppressor in which expression is significantly reduced in human cancer cell lines and primary tumors. The proapoptotic effects of XAF1 have been attributed to both caspase-dependent and -independent means. In particular, XAF1 reverses the anti-caspase activity of XIAP, a physiological inhibitor of apoptosis. We further investigated the function of XAF1 by examining its relationship with other IAPs. Immunoprecipitation studies indicate that XAF1 binds to XIAP, cIAP1, cIAP2, Livin, TsIAP, and NAIP but not Survivin, an IAP that prevents mitotic catastrophe and in which antiapoptotic activity is exerted through direct XIAP interaction and stabilization. We found that overexpressed XAF1 down-regulates the protein expression of Survivin. Under these conditions, Survivin expression was restored in the presence of the proteasome inhibitor MG132 or a XIAP RING mutant that is defective in ubiquitin-protein isopeptide ligase (E3) activity, suggesting that XAF1 interaction activates E3 activity of XIAP and targets Survivin by direct ubiquitination. In addition, RNA interference targeting endogenous XIAP protected Survivin degradation by XAF1. Furthermore, interferon-beta-mediated XAF1 induction promoted formation of an endogenous XIAP-XAF1-Survivin complex. This complex facilitated Survivin degradation, which was prevented in XAF1(-/-) stable clones. Altogether, our study demonstrates that XAF1 mediates Survivin down-regulation through a complex containing XIAP, supporting dual roles for XAF1 in apoptosis and mitotic catastrophe. 相似文献
94.
Puri SC Amna T Khajuria A Gupta A Arora R Spiteller M Qazi GN 《Acta microbiologica et immunologica Hungarica》2007,54(3):237-260
A novel camptothecin-producing endophytic fungus viz., Entrophospora infrequens was isolated from an important Indian medicinal plant Nothapodytes foetida. The present study reports evaluation ofbioactivities of two novel extracts viz., chloroform (CEEI) and methanolic (MEEI) extracts of Entrophospora infrequens with respect to their immunomodulatory potential in vitro and in vivo (in Balb/c mice). The endophyte E. infrequens was found to synthesize camptothecin, which tested positive in CEEI. The immunomodulatory potential of CEEI and MEEI was compared with standard camptothecin (CPT). Doses of the chloroform extract (CEEI) ranging from 12.5-100 mg/kg body weight, significantly (p < 0.05) stimulated the humoral and cell-mediated immune responses in a dose-dependent manner. MEEI on the other hand significantly (p < 0.05) stimulated the delayed type hypersensitivity (DTH) reaction (by nearly 80%), plaque forming cell (PFC) assay (33%), phagocytic response (38%) and haemagglutination antibody (HA) titre [IgM by 79.07% and IgG by 62.05%] at a dose of 12.5 mg/kg body weight. The present study is the first report of the immunomodulatory potential of this neoteric camptothecin-producing endophyte from Nothapodytes foetida. 相似文献
95.
The Indian pygmy field mouse, Mus terricolor, is a tiny, yet economically and ecologically important crop pest found throughout South-East Asia. There are no systematic reports exploring its reproductive physiology. We report the presence of distinct periods of annual reproductive activity and quiescence in M. terricolor. Body weight in males and females, relative weights of testis, epididymis and seminal vesicle in males, ovarian and uterine weight in females, gonadal histomorphic changes, testicular and ovarian cholesterol, sialic acid in epididymis, fructose in seminal vesicle, uterine protein content, melatonin in males and females, testosterone in males, estradiol, and progesterone in females were studied over a period of three years in both wild-caught and lab-acclimated mice. The number of Graafian follicles and corpora lutea, and plasma estradiol and progesterone, along with relative weights of ovary and uterus in females exhibited a peak in the months of October–January, compared to June. Based on histomorphic and hormonal status, the major reproductively active season is the winter (short-day breeding). There is a brief period of sub-maximal reproductive activity in April. M. terricolor is reproductively inactive in the summer, monsoons, and autumn. The results establish M. terricolor as a seasonal breeder in the field, with interesting implications for pest management. 相似文献
96.
Shikha Verma Anamika Sharma Raj Kumar Charanjit Kaur Anju Arora Raghubir Shah Lata Nain 《Saudi Journal of Biological Sciences》2015,22(3):256-264
Nutrient management practices play a significant role in improving the nutritional quality of tomato. The present study deals with the evaluation of compost prepared using Effective Microorganisms (EM), on antioxidant and defense enzyme activities of Tomato (Lycopersicon esculentum). A field experiment with five treatments (control, chemical fertilizer and EM compost alone and in combination) was conducted in randomized block design. An increment of 31.83% in tomato yield was recorded with the combined use of EM compost and half recommended dose of chemical fertilizers (N50P30K25 + EM compost at the rate of 5 t ha−1). Similarly, fruit quality was improved in terms of lycopene content (35.52%), antioxidant activity (24–63%) and defense enzymes activity (11–54%), in tomatoes in this treatment as compared to the application of recommended dose of fertilizers. Soil microbiological parameters also exhibited an increase of 7–31% in the enzyme activities in this treatment. Significant correlation among fruit quality parameters with soil microbiological activities reveals the positive impact of EM compost which may be adopted as an eco-friendly strategy for production of high quality edible products. 相似文献
97.
Reversible cell cycle inhibition and premature aging features imposed by conditional expression of p16Ink4a
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Amelie Boquoi Sanjeevani Arora Tina Chen Sam Litwin James Koh Greg H. Enders 《Aging cell》2015,14(1):139-147
The cyclin‐dependent kinase (Cdk) inhibitor p16Ink4a (p16) is a canonical mediator of cellular senescence and accumulates in aging tissues, where it constrains proliferation of some progenitor cells. However, whether p16 induction in tissues is sufficient to inhibit cell proliferation, mediate senescence, and/or impose aging features has remained unclear. To address these issues, we generated transgenic mice that permit conditional p16 expression. Broad induction at weaning inhibited proliferation of intestinal transit‐amplifying and Lgr5+ stem cells and rapidly imposed features of aging, including hair loss, skin wrinkling, reduced body weight and subcutaneous fat, an increased myeloid fraction in peripheral blood, poor dentition, and cataracts. Aging features were observed with multiple combinations of p16 transgenes and transactivators and were largely abrogated by a germline Cdk4 R24C mutation, confirming that they reflect Cdk inhibition. Senescence markers were not found, and de‐induction of p16, even after weeks of sustained expression, allowed rapid recovery of intestinal cell proliferation and reversal of aging features in most mice. These results suggest that p16‐mediated inhibition of Cdk activity is sufficient to inhibit cell proliferation and impose aging features in somatic tissues of mammals and that at least some of these aging features are reversible. 相似文献
98.
Alsaba F Raja Furqan Ali Inshad A Khan Abdul S Shawl Daljit S Arora Bhahwal A Shah Subhash C Taneja 《BMC microbiology》2011,11(1):54
Background
Boswellic acids are pentacyclic triterpenes, which are produced in plants belonging to the genus Boswellia. Boswellic acids appear in the resin exudates of the plant and it makes up 25-35% of the resin. β-boswellic acid, 11-keto-β-boswellic acid and acetyl-11-keto-β-boswellic acid have been implicated in apoptosis of cancer cells, particularly that of brain tumors and cells affected by leukemia or colon cancer. These molecules are also associated with potent antimicrobial activities. The present study describes the antimicrobial activities of boswellic acid molecules against 112 pathogenic bacterial isolates including ATCC strains. Acetyl-11-keto-β-boswellic acid (AKBA), which exhibited the most potent antibacterial activity, was further evaluated in time kill studies, postantibiotic effect (PAE) and biofilm susceptibility assay. The mechanism of action of AKBA was investigated by propidium iodide uptake, leakage of 260 and 280 nm absorbing material assays. 相似文献99.
100.