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131.
Liu X Bandyopadhyay BC Bandyopadhyay B Nakamoto T Singh B Liedtke W Melvin JE Ambudkar I 《The Journal of biological chemistry》2006,281(22):15485-15495
Regulation of cell volume in response to changes in osmolarity is critical for cell function and survival. However, the molecular basis of osmosensation and regulation of cell volume are not clearly understood. We have examined the mechanism of regulatory volume decrease (RVD) in salivary gland cells and report a novel association between osmosensing TRPV4 (transient receptor potential vanalloid 4) and AQP5 (aquaporin 5), which is required for regulating water permeability and cell volume. Exposure of salivary gland cells and acini to hypotonicity elicited an increase in cell volume and activation of RVD. Hypotonicity also activated Ca2+ entry, which was required for subsequent RVD. Ca2+ entry was associated with a distinct nonselective cation current that was activated by 4alphaPDD and inhibited by ruthenium red, suggesting involvement of TRPV4. Consistent with this, endogenous TRPV4 was detected in cells and in the apical region of acini along AQP5. Importantly, acinar cells from mice lacking either TRPV4 or AQP5 displayed greatly reduced Ca2+ entry and loss of RVD in response to hypotonicity, although the extent of cell swelling was similar. Expression of N terminus-deleted AQP5 suppressed TRPV4 activation and RVD but not cell swelling. Furthermore, hypotonicity increased the association and surface expression of AQP5 and TRPV4. Both these effects and RVD were reduced by actin depolymerization. These data demonstrate that (i) activation of TRPV4 by hypotonicity depends on AQP5, not on cell swelling per se, and (ii) TRPV4 and AQP5 concertedly control regulatory volume decrease. These data suggest a potentially important role for TRPV4 in salivary gland function. 相似文献
132.
A "traffic control" role for TGFbeta3: orchestrating dermal and epidermal cell motility during wound healing 总被引:1,自引:0,他引:1 下载免费PDF全文
Bandyopadhyay B Fan J Guan S Li Y Chen M Woodley DT Li W 《The Journal of cell biology》2006,172(7):1093-1105
Cell migration is a rate-limiting event in skin wound healing. In unwounded skin, cells are nourished by plasma. When skin is wounded, resident cells encounter serum for the first time. As the wound heals, the cells experience a transition of serum back to plasma. In this study, we report that human serum selectively promotes epidermal cell migration and halts dermal cell migration. In contrast, human plasma promotes dermal but not epidermal cell migration. The on-and-off switch is operated by transforming growth factor (TGF) beta3 levels, which are undetectable in plasma and high in serum, and by TGFbeta receptor (TbetaR) type II levels, which are low in epidermal cells and high in dermal cells. Depletion of TGFbeta3 from serum converts serum to a plasmalike reagent. The addition of TGFbeta3 to plasma converts it to a serumlike reagent. Down-regulation of TbetaRII in dermal cells or up-regulation of TbetaRII in epidermal cells reverses their migratory responses to serum and plasma, respectively. Therefore, the naturally occurring plasma-->serum-->plasma transition during wound healing orchestrates the orderly migration of dermal and epidermal cells. 相似文献
133.
Aflatoxin contamination of maize by Aspergillus flavus poses serious potential economic losses in the US and health hazards to humans, particularly in West Africa. The Southern
Regional Research Center of the United States Department of Agriculture, Agricultural Research Service (USDA-ARS-SRRC) and
the International Institute of Tropical Agriculture (IITA) initiated a collaborative breeding project to develop maize germplasm
with resistance to aflatoxin accumulation. Resistant genotypes from the US and selected inbred lines from IITA were used to
generate backcrosses with 75% US germplasm and F1 crosses with 50% IITA and 50% US germplasm. A total of 65 S4 lines were developed from the backcross populations and 144 S4 lines were derived from the F1 crosses. These lines were separated into groups and screened in SRRC laboratory using a kernel-screening assay. Significant
differences in aflatoxin production were detected among the lines within each group. Several promising S4 lines with aflatoxin values significantly lower than their respective US resistant recurrent parent or their elite tropical
inbred parent were selected for resistance-confirmation tests. We found pairs of S4 lines with 75–94% common genetic backgrounds differing significantly in aflatoxin accumulation. These pairs of lines are
currently being used for proteome analysis to identify resistance-associated proteins and the corresponding genes underlying
resistance to aflatoxin accumulation. Following confirmation tests in the laboratory, lines with consistently low aflatoxin
levels will be inoculated with A. flavus in the field in Nigeria to identify lines resistant to strains specific to both US and West Africa. Maize inbred lines with
desirable agronomic traits and low levels of aflatoxin in the field would be released as sources of genes for resistance to
aflatoxin production. 相似文献
134.
Venkateshwaran Muthusubramanian Ranajit Bandyopadhyay Daram Rajaram Reddy Paul W. Tooley 《Mycological Research》2006,110(4):452-464
Sorghum ergot in India is caused by Claviceps africana and C. sorghi. The distributions of these two species in India is not known. Eighty-nine sorghum ergot isolates were cultured from young sphacelia obtained from male sterile sorghum plants artificially inoculated using inoculum collected in the field. Based on cultural characteristics, the isolates were separated into two groups which differed distinctly in the morphology of their sphacelia, conidia, and sclerotia. Marked differences also were observed in rates of secondary conidial production and disease spread between the groups. In combination with molecular evidence, our results confirm that the isolates placed in Group I represent C. africana and Group II isolates represent C. sorghi. C. africana was found to be widely distributed in all sorghum growing areas of India. The species first described as occuring in India, C. sorghi, appears to be restricted to a few locations in the states of Maharashtra, Andhra Pradesh, and Karnataka. 相似文献
135.
Bandyopadhyay D Huan J Liu J Prins J Snoeyink J Wang W Tropsha A 《Protein science : a publication of the Protein Society》2006,15(6):1537-1543
We describe a method to assign a protein structure to a functional family using family-specific fingerprints. Fingerprints represent amino acid packing patterns that occur in most members of a family but are rare in the background, a nonredundant subset of PDB; their information is additional to sequence alignments, sequence patterns, structural superposition, and active-site templates. Fingerprints were derived for 120 families in SCOP using Frequent Subgraph Mining. For a new structure, all occurrences of these family-specific fingerprints may be found by a fast algorithm for subgraph isomorphism; the structure can then be assigned to a family with a confidence value derived from the number of fingerprints found and their distribution in background proteins. In validation experiments, we infer the function of new members added to SCOP families and we discriminate between structurally similar, but functionally divergent TIM barrel families. We then apply our method to predict function for several structural genomics proteins, including orphan structures. Some predictions have been corroborated by other computational methods and some validated by subsequent functional characterization. 相似文献
136.
Shachindra K. Pandey Kunwar Digvijay Narayan Saumya Bandyopadhyay Kinshuk C. Nayak Subrata K. Das 《Current microbiology》2009,58(5):516-521
A bacterial isolate S23 capable of oxidizing thiosulfate was isolated from a sulfur spring. Strain S23 is gram-negative, aerobic,
and motile. The G + C content of DNA is 61.4 mol%. The fatty acid composition and phylogenetic analysis of the 16S rRNA gene
sequence of strain S23 showed that it is related to the members of the genus Comamonas, and most closely related to Comamonas testosteroni (99.9% sequence similarity). The isolate S23 exhibited thiosulfate oxidation under a mixotrophic growth condition. Polymerase
chain reaction (PCR) using soxB-specific primers and DNA sequencing showed the presence of the soxB gene. This is the first report in Comamonas sp. showing thiosulfate oxidation under a mixotrophic growth condition. 相似文献
137.
Bone microstructure is affected by ontogeny, phylogeny, biomechanics and environments. These aspects of life history of an
extinct animal, especially its growth patterns, may be assessed as fossil bone generally maintains its histological integrity.
Recent studies on the bone histology of fossil vertebrates from India encompass different types of temnospondyls and dicynodonts
from different Permian and Triassic horizons. The examined taxa show that they had distinct bone histology and varied growth
patterns. The Early Triassic trematosaurids had an overall fast growth, which contrasts with that of the Middle and Late Triassic
temnospondyl taxa examined. The dicynodonts on the other hand, were characterized by an overall fast growth with periodic
interruptions, variable growth rates dependent on ontogeny and indeterminate growth strategy. A comparative study encompassing
several neotherapsid genera including the dicynodonts shows significant evolutionary trends towards determinate growth strategy
and reduced developmental plasticity. 相似文献
138.
Osteohistological analysis of the dicynodonts Endothiodon, Diictodon, Lystrosaurus and Wadiasaurus reveals distinctly different growth patterns within a framework of an overall fast growth. The late Permian endemic taxon from India, Endothiodon mahalanobisi and the South African Diictodon feliceps had periodic fast growth. The early Triassic Lystrosaurus murrayi and the middle Triassic Wadiasaurus indicus had an initial fast growth followed by a relatively slow growth later in ontogeny as is observed from the presence of peripheral parallel fibred bone. Although all examined dicynodont genera had an indeterminate growth strategy, the bone microstructure of Wadiasaurus suggests that its growth was much slower than that of other dicynodonts examined. Mapping of osetohistological character states on a cladogram depicting the inter-relationship between available neotherapsid genera shows that fibrolamellar bone tissue, overall fast growth and indeterminate growth strategy were plesiomorphic for the neotherapsids. A considerable reduction in developmental plasticity and evolution of apparently independent growth trajectories from environmental conditions are evident within the non-mammalian cynodonts, with the advanced tritylodontids achieving almost a mammalian growth trajectory. 相似文献
139.
Availability of genome sequences of pathogens has provided a tremendous amount of information that can be useful in drug target and vaccine target identification. One of the recently adopted strategies is based on a subtractive genomics approach, in which the subtraction dataset between the host and pathogen genome provides information for a set of genes that are likely to be essential to the pathogen but absent in the host. This approach has been used successfully in recent times to identify essential genes in Pseudomonas aeruginosa. We have used the same methodology to analyse the whole genome sequence of the human gastric pathogen Helicobacter pylori. Our analysis revealed that out of the 1590 coding sequences of the pathogen, 40 represent essential genes that have no human homolog. We have further analysed these 40 genes by the protein sequence databases to list some 10 genes whose products are possibly exposed on the pathogen surface. This preliminary work reported here identifies a small subset of the Helicobacter proteome that might be investigated further for identifying potential drug and vaccine targets in this pathogen. 相似文献
140.