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1.
Shailesh Kumar Atma P. Dwivedi Vivek Kr. Kashyap A.K. Saxena A.K. Dwivedi Ranjana Srivastava Devi P. Sahu 《Bioorganic & medicinal chemistry letters》2013,23(8):2404-2407
Synthesis of a library of novel trans 6-methoxy-1,1-dimethyl-2-phenyl-3-aryl-2,3-dihydro-1H-inden-4-yloxy alkyl amines and their antimycobacterial activity against drug sensitive and multidrug resistant strains of Mycobacterium tuberculosis have been reported. All the new compounds in the series exhibited MIC between 1.56 and 6.25 μg/ml. Two compounds 1i and 1j with low MIC and low cytotoxicity showed significant reduction in CFU in infected mouse macrophages at 1× MIC concentration. The compound 1i inhibited the growth of M. tuberculosis in mice at 100 mg/kg dose with 1.35 log10 reduction of CFU in lungs tissue and was active against non-replicating Mycobacterium tuberculosis under anaerobic condition. 相似文献
2.
Kainate receptors (KARs) are a class of ionotropic glutamate receptors that are expressed throughout the central nervous system. The function and subcellular localization of KARs are tightly regulated by accessory proteins. We have previously identified the single-pass transmembrane proteins, Neto1 and Neto2, to be associated with native KARs. In the hippocampus, Neto1, but not Neto2, controls the abundance and modulates the kinetics of postsynaptic KARs. Here we evaluated whether Neto2 regulates synaptic KAR levels in the cerebellum where Neto1 expression is limited to the deep cerebellar nuclei. In the cerebellum, where Neto2 is present abundantly, we found a ∼40% decrease in GluK2-KARs at the postsynaptic density (PSD) of Neto2-null mice. No change, however, was observed in total level of GluK2-KARs, thereby suggesting a critical role of Neto2 on the synaptic localization of cerebellar KARs. The presence of a putative class II PDZ binding motif on Neto2 led us to also investigate whether it interacts with PDZ domain-containing proteins previously implicated in regulating synaptic abundance of KARs. We identified a PDZ-dependent interaction between Neto2 and the scaffolding protein GRIP. Furthermore, coexpression of Neto2 significantly increased the amount of GRIP associated with GluK2, suggesting that Neto2 may promote and/or stabilize GluK2:GRIP interactions. Our results demonstrate that Neto2, like Neto1, is an important auxiliary protein for modulating the synaptic levels of KARs. Moreover, we propose that the interactions of Neto1/2 with various scaffolding proteins is a critical mechanism by which KARs are stabilized at diverse synapses. 相似文献
3.
Vivek R. Nerurkar Ki-Joon Song Rebecca R. Melland Richard Yanagihara 《Molecular neurobiology》1994,8(2-3):155-173
Molecular variants of human T-cell lymphotropic virus type I (HTLV-I) have been isolated recently from lifelong residents
of remote Melanesian populations, including a Solomon Islander with tropical spastic paraparesis/HTLV-I-associated myelopathy
(TSP/HAM) or HTLV-I myeloneuropathy. To clarify the genetic heterogeneity and molecular epidemiology of disease-associated
strains of HTLV-I, we enzymatically amplified, then directly sequenced representative regions of thegag, pol, env, andpX genes of HTLV-I strains from Melanesians with and without TSP/HAM, and aligned and compared these sequences with those of
HTLV-I strains from patients with TSP/HAM or adult T-cell leukemia/lymphoma and from asymptomatic carriers from widely separated
and culturally disparate populations. Overall, the HTLV-I variant from the Solomon Islander with TSP/HAM, like HTLV-I strains
from asymptomatically infected Melanesians, diverged by approx 7% from cosmopolitan HTLV-I strain. No disease-specific viral
sequences were found. Gene phylogenies, as determined by the unweighted pair-goup method of assortment and by the maximum
parsimony method, indicated that the Melanesian and cosmopolitan strains of HTLV-I have evolved along separate geographically
dependent lineages, one comprised of HTLV-I strains from Papua New Guinea and the Solomon Islands, and the other composed
of virus strains from Japan, India, the Caribbean, Polynesia, the Americas, and Africa. The total absence of nonhuman primates
in Papua New Guinea and the Solomon Islands precludes any possibility that the Melanesian HTLV-I strains have evolved recently
from the simian homolog of HTLV-I. 相似文献
4.
Arjun Srivathsa Vivek Ramachandran Pooja Saravanan Abhijith Sureshbabu Divyajyoti Ganguly Uma Ramakrishnan 《Biological reviews of the Cambridge Philosophical Society》2023,98(6):2114-2135
Intraguild interactions among carnivores have long held the fascination of ecologists. Ranging from competition to facilitation and coexistence, these interactions and their complex interplay influence everything from species persistence to ecosystem functioning. Yet, the patterns and pathways of such interactions are far from understood in tropical forest systems, particularly across countries in the Global South. Here, we examined the determinants and consequences of competitive interactions between dholes Cuon alpinus and the two large felids (leopards Panthera pardus and tigers Panthera tigris) with which they most commonly co-occur across Asia. Using a combination of traditional and novel data sources (N = 118), we integrate information from spatial, temporal, and dietary niche dimensions. These three species have faced catastrophic declines in their extent of co-occurrence over the past century; most of their source populations are now confined to Protected Areas. Analysis of dyadic interactions between species pairs showed a clear social hierarchy. Tigers were dominant over dholes, although pack strength in dholes helped ameliorate some of these effects; leopards were subordinate to dholes. Population-level spatio-temporal interactions assessed at 25 locations across Asia did not show a clear pattern of overlap or avoidance between species pairs. Diet-profile assessments indicated that wild ungulate biomass consumption by tigers was highest, while leopards consumed more primate and livestock prey as compared to their co-predators. In terms of prey offtake (ratio of wild prey biomass consumed to biomass available), the three species together harvested 0.4–30.2% of available prey, with the highest offtake recorded from the location where the carnivores reach very high densities. When re-examined in the context of prey availability and offtake, locations with low wild prey availability showed spatial avoidance and temporal overlap among the carnivore pairs, and locations with high wild prey availability showed spatial overlap and temporal segregation. Based on these observations, we make predictions for 40 Protected Areas in India where temporally synchronous estimates of predator and prey densities are available. We expect that low prey availability will lead to higher competition, and in extreme cases, to the complete exclusion of one or more species. In Protected Areas with high prey availability, we expect intraguild coexistence and conspecific competition among carnivores, with spill-over to forest-edge habitats and subsequent prey-switching to livestock. We stress that dhole–leopard–tiger co-occurrence across their range is facilitated through an intricate yet fragile balance between prey availability, and intraguild and conspecific competition. Data gaps and limitations notwithstanding, our study shows how insights from fundamental ecology can be of immense utility for applied aspects like large predator conservation and management of human–carnivore interactions. Our findings also highlight potential avenues for future research on tropical carnivores that can broaden current understanding of intraguild competition in forest systems of Asia and beyond. 相似文献
5.
David A. Watson Vivek Kapur Daniel M. Musher James W. Jacobson James M. Musser 《Current microbiology》1995,31(4):251-259
This paper reports the cloning and sequencing of a region of DNA from Streptococcus pneumoniae serotype 3 surrounding transposon Tn916, insertion of which was previously shown to result in lack of expression of the extracellular capsule. Sequence analysis revealed that the transposon inserted into a consensus insertion site 71 bp from the 5 end of the cloned fragment. Within the clone, 3 downstream regions from two different pneumococcal lytA genes were identified, as well as a putative 194 AA open reading frame (ORF1). Moreover, two copies of the repeat element BOX, oriented in opposite directions, were located immediately 3 of orf1. Within the region bounded by the first pair of internal sequencing primers, analysis revealed that the fragment amplified by PCR was always of the same size. Moreover, Southern blotting showed that for all serotypes examined to date, homology exists with the cloned fragment. These results indicate that this region of the chromosome is highly conserved and, taken together with other independently derived data, suggest that interruptions or deletions within this DNA lead to unencapsulation. 相似文献
6.
Christoph J. Hueck Michael J. Hantman Vivek Bajaj Christine Johnston Catherine A. Lee Samuel I. Miller 《Molecular microbiology》1995,18(3):479-490
Salmonella typhimurium secreted proteins (Ssp) were previously implicated in epithelial cell invasion. Here we describe four genes ( sspB , sspC , sspD , and sspA ), located between spaT and prgH , which encode proteins of 63, 42, 36, and 87 kDa, respectively. These Ssp are homologous to Shigella flexneri secreted proteins lpaB, lpaC, lpaD and lpaA. A non-invasive mutant with a transposon insertion in sspC lacks Ssp of 87,42 and 36 kDa. Complementation analyses show that sspC and sspD encode the 42 and the 36 kDa Ssp, while the 87 kDa Ssp is encoded by sspA . sspC and sspD , but not sspA are required for invasion. Amino-terminal sequencing shows that SspC and SspA are secreted without amino-terminal processing. We further demonstrate that Ssp secretion requires proteins encoded by prgHIJK , homologous to the Shigella lpa secretion system, since SspA is abundantly secreted by wild-type bacteria but is completely retained within the cellular fraction of a prgHIJK mutant. A precipitate containing abundant SspC and three other major Ssp of 63,59 and 22 kDa was isolated from culture supernatants of wild-type bacteria. These data indicate that major secreted invasion determinants of S. typhimurium are structurally and functionally homolgous to S. flexneri lpa proteins. 相似文献
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9.
The influence of dose rate on expression time, cell survival and mutant frequency at the hypoxanthine-guanine phosphoribosyltransferase (HPRT) locus was evaluated in human G(0) peripheral blood lymphocytes exposed in vitro to gamma rays at low (0.0014 Gy/min) and high (0.85 Gy/min) dose rates. A cloning assay performed on different days of postirradiation incubation indicated an 8-day maximum expression period for the induction of HPRT mutants at both high and low dose rates. Cell survival increased markedly with decreasing dose rate, yielding D(0) values of 3.04 Gy and 1.3 Gy at low and high dose rates, respectively. The D(0) of 3.04 Gy obtained at low dose rate could be attributed to the repair of sublethal DNA damage taking place during prolonged exposure to low-LET radiation. Regression analysis of the mutant frequency yielded slopes of 12.35 x 10(-6) and 3.66 x 10(-6) mutants per gray at high and low dose rate, respectively. A dose and dose-rate effectiveness factor of 3.4 indicated a marked dose-rate effect on the induced HPRT mutant frequency. The results indicate that information obtained from in vitro measurements of dose-rate effects in human G(0) lymphocytes may be a useful parameter for risk estimation in radiation protection. 相似文献
10.