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排序方式: 共有232条查询结果,搜索用时 15 毫秒
91.
The present study was undertaken in the Blue rock pigeon (Columba livia) to evaluate the annual semen characteristics, to identify a suitable extender for semen short-term storage, to determine a protocol for cryopreservation of semen and finally to check whether intracloacal insemination would lead to the birth of a chick. Semen characteristics such as semen volume, sperm concentration, sperm motility, and percentage of normal spermatozoa were maximum during the monsoon season. TALP was observed to be the most suitable semen extender and the sperm survived best at 37 degrees C at a dilution of 1:100 in TALP. Further, cryopreservation studies on pigeon semen indicated that 8% DMSO with or without egg yolk (20%) proved to be a better cryoprotectant compared to glycerol and polyethylene glycol. In addition, the slow freezing protocol was better than the fast-freezing protocol and about 40% of the cryopreserved spermatozoa were motile following thawing. Computer-aided semen analysis indicated that pigeon spermatozoa were extremely active immediately after dilution in TALP and exhibited linear trajectories persisting up to 9h. But, with time there was a time-dependent decrease in the velocity parameters (VAP, VSL, and VCL). Cryopreserved spermatozoa following thawing also exhibited linear trajectories but had reduced velocity as evident from the significant decrease in VAP, VSL, and VCL. Further, artificial inseminations using fresh semen resulted in 45% fertilization and birth of a live chick. 相似文献
92.
A new polyisoprenylated benzophenone, guttiferone I, together with the known compounds cambogin, 1,7-dihydroxyxanthone, 1,3,6,7-tetrahydroxyxanthone and 1,3,5,6-tetrahydroxyxanthone were isolated from the stem bark of Garcinia griffithii. The acetone extract of the heartwood of Garcinia mangostana contained one new diprenylated xanthone (mangoxanthone) and a new benzophenone (3',6-dihydroxy-2,4,4'-trimethoxybenzophenone) as well as the known xanthones dulxanthone D, 1,3,7-trihydroxy-2-methoxyxanthone, 1,3,5-trihydroxy-13,13-dimethyl-2H-pyran[7,6-b]xanthen-9-one. Their structures were established on the basis of spectroscopic studies and chemical correlation. 相似文献
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96.
Padma P. Nanaware Manoj P. Ramteke Arun K. Somavarapu Prasanna Venkatraman 《Proteins》2014,82(7):1283-1300
Gankyrin, a non‐ATPase component of the proteasome and a chaperone of proteasome assembly, is also an oncoprotein. Gankyrin regulates a variety of oncogenic signaling pathways in cancer cells and accelerates degradation of tumor suppressor proteins p53 and Rb. Therefore gankyrin may be a unique hub integrating signaling networks with the degradation pathway. To identify new interactions that may be crucial in consolidating its role as an oncogenic hub, crystal structure of gankyrin‐proteasome ATPase complex was used to predict novel interacting partners. EEVD, a four amino acid linear sequence seems a hot spot site at this interface. By searching for EEVD in exposed regions of human proteins in PDB database, we predicted 34 novel interactions. Eight proteins were tested and seven of them were found to interact with gankyrin. Affinity of four interactions is high enough for endogenous detection. Others require gankyrin overexpression in HEK 293 cells or occur endogenously in breast cancer cell line‐ MDA‐MB‐435, reflecting lower affinity or presence of a deregulated network. Mutagenesis and peptide inhibition confirm that EEVD is the common hot spot site at these interfaces and therefore a potential polypharmacological drug target. In MDA‐MB‐231 cells in which the endogenous CLIC1 is silenced, trans‐expression of Wt protein (CLIC1_EEVD) and not the hot spot site mutant (CLIC1_AAVA) resulted in significant rescue of the migratory potential. Our approach can be extended to identify novel functionally relevant protein‐protein interactions, in expansion of oncogenic networks and in identifying potential therapeutic targets. Proteins 2014; 82:1283–1300. © 2013 Wiley Periodicals, Inc. 相似文献
97.
Tang YD Pandey A Kolmakova A Wang XT Venkatraman SS Chatterjee S Boey FY 《Glycoconjugate journal》2009,26(6):721-732
Drug eluting stents (DES) have become a common mode of treatment for stenosis in coronary arteries. However, currently, the
use of sirolimus/paclitaxel-coated DES has come under scrutiny, because of their pro-thrombotic effects leading to potential
adverse outcomes in the long run. We have previously documented that d-threo-1-phenyl-2-decanoylamino-3-morholino propanol (D-PDMP); an inhibitor of glucosylceramide synthase and lactosylceramide
(LacCer) synthase markedly inhibited platelet-derived growth factor (PDGF)-induced cell proliferation. We have fabricated
DES wherein, D-PDMP or sirolimus was coated on to a double layer of poly (lactic-co-glycolic acid) on a bare metal stent.
The in vitro release of D-PDMP from biopolymer and its consequent effect on PDGF induced proliferation and apoptosis was assessed in human
aortic smooth muscle cells (ASMC). D-PDMP was released from biopolymers in a dose-dependent fashion and was accompanied with
a decrease in PDGF-induced cell proliferation, but not apoptosis. In contrast, sirolimus markedly increased apoptosis in these
cells in addition to inhibiting proliferation. Our mechanistic studies revealed that D-PDMP, but not sirolimus decreased the
cellular level of glucosyl and lactosylceramide that accompanied inhibition of PDGF-induced cell proliferation. Our short-term
(14 days) in vivo studies in rabbits also attested to the safety and biocompatibility of the D-PDMP coated stents. Our data reveal the superiority
of D-PDMP coated biopolymers over sirolimus coated biopolymers in mitigating ASMC proliferation. Such D-PDMP coated stents
may be useful for localized delivery of drug to mitigate neo-vascular hyperplasia and other proliferative disorders.
Yong-Dan Tang, Ambarish Pandey, Subbu S. Venkatraman, and Subroto Chatterjee contributed equally to this work. 相似文献
98.
Arasappan A Njoroge FG Chen KX Venkatraman S Parekh TN Gu H Pichardo J Butkiewicz N Prongay A Madison V Girijavallabhan V 《Bioorganic & medicinal chemistry letters》2006,16(15):3960-3965
Synthesis and HCV NS3 serine protease inhibitory activity of 4-hydroxyproline derived macrocyclic inhibitors and SAR around this macrocyclic core is described in this communication. X-ray structure of inhibitor 38 bound to the protease is discussed. 相似文献
99.
Frank Bennett Yuhua Huang Siska Hendrata Raymond Lovey Stephane L. Bogen Weidong Pan Zhuyan Guo Andrew Prongay Kevin X. Chen Ashok Arasappan Srikanth Venkatraman Francisco Velazquez Latha Nair Mousumi Sannigrahi Xiao Tong John Pichardo Kuo-Chi Cheng Viyyoor M. Girijavallabhan Anil K. Saksena F. George Njoroge 《Bioorganic & medicinal chemistry letters》2010,20(8):2617-2621
In the search for a second generation HCV protease inhibitor, molecular modeling studies of the X-ray crystal structure of Boceprevir® 1 bound to the NS3 protein suggest that expansion into the S4 pocket could provide additional hydrophobic Van der Waals interactions. Effective replacement of the P4 tert-butyl with a cyclohexylmethyl ligand led to inhibitor 2 with improved enzyme and replicon activities. Subsequent modeling and SAR studies led to the pyridine 38 and sulfone analogues 52 and 53 with vastly improved PK parameters in monkeys, forming a new foundation for further exploration. 相似文献
100.
Venkatraman Junnotula Anuruddha Rajapakse Leire Arbillaga Adela López de Cerain Beatriz Solano Raquel Villar Antonio Monge Kent S. Gates 《Bioorganic & medicinal chemistry》2010,18(9):3125-3132
The heterocyclic N-oxide, 3-amino-1,2,4-benzotriazine 1,4-dioxide (tirapazamine, 1), shows promising antitumor activity in preclinical studies, but there is a continuing need to explore new compounds in this general structural category. In the work described here, we examined the properties of 7-chloro-2-thienylcarbonyl-3-trifluoromethylquinoxaline 1,4-dioxide (9h). We find that 9h causes redox-activated, hypoxia-selective DNA cleavage that mirrors the lead compound, tirapazamine, in both mechanism and potency. Furthermore, we find that 9h displays hypoxia-selective cytotoxicity against human cancer cell lines. 相似文献