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151.
Kevin W. Millsapa Henny C. van der Meia Rolf Bosa Henk J. Busschera 《FEMS microbiology reviews》1998,21(4):321-336
152.
Daniel S. Brenner Judith P. Golden Sherri K. Vogt Robert W. Gereau IV 《Journal of visualized experiments : JoVE》2015,(97)
Cold hypersensitivity is a serious clinical problem, affecting a broad subset of patients and causing significant decreases in quality of life. The cold plantar assay allows the objective and inexpensive assessment of cold sensitivity in mice, and can quantify both analgesia and hypersensitivity. Mice are acclimated on a glass plate, and a compressed dry ice pellet is held against the glass surface underneath the hindpaw. The latency to withdrawal from the cooling glass is used as a measure of cold sensitivity.Cold sensation is also important for survival in regions with seasonal temperature shifts, and in order to maintain sensitivity animals must be able to adjust their thermal response thresholds to match the ambient temperature. The Cold Plantar Assay (CPA) also allows the study of adaptation to changes in ambient temperature by testing the cold sensitivity of mice at temperatures ranging from 30 °C to 5 °C. Mice are acclimated as described above, but the glass plate is cooled to the desired starting temperature using aluminum boxes (or aluminum foil packets) filled with hot water, wet ice, or dry ice. The temperature of the plate is measured at the center using a filament T-type thermocouple probe. Once the plate has reached the desired starting temperature, the animals are tested as described above.This assay allows testing of mice at temperatures ranging from innocuous to noxious. The CPA yields unambiguous and consistent behavioral responses in uninjured mice and can be used to quantify both hypersensitivity and analgesia. This protocol describes how to use the CPA to measure cold hypersensitivity, analgesia, and adaptation in mice. 相似文献
153.
Fluorescence-based assays for the cytochrome P450 BM3 monooxygenase from Bacillus megaterium address an attractive biotechnological challenge by facilitating enzyme engineering and the identification of potential substrates of this highly promising biocatalyst. In the current study, we used the scarcity of corresponding screening systems as an opportunity to evaluate a novel and continuous high-throughput assay for this unique enzyme. A set of nine catalytically diverse P450 BM3 variants was constructed and tested toward the native substrate-inspired fluorogenic substrate 12-(4-trifluoromethylcoumarin-7-yloxy)dodecanoic acid. Particularly high enzyme-mediated O-dealkylation yielding the fluorescent product 7-hydroxy-4-trifluoromethylcoumarin was observed with mutants containing the F87V substitution, with A74G/F87V showing the highest catalytic efficiency (0.458 min−1 μM−1). To simplify the assay procedure and show its versatility, different modes of application were successfully demonstrated, including (i) the direct use of NADPH or its oxidized form NADP+ along with diverse NADPH recycling systems for electron supply, (ii) the use of cell-free lysates and whole-cell preparations as the biocatalyst source, and (iii) its use for competitive inhibition screens to identify or characterize substrates and inhibitors. A detailed comparison with known, fluorescence-based P450 BM3 assays finally emphasizes the relevance of our contribution to the ongoing research. 相似文献
154.
Samik Chakraborty Minakshi Mazumdar Shravanti Mukherjee Pushpak Bhattacharjee Arghya Adhikary Argha Manna Sreeparna Chakraborty Poulami Khan Aparna Sen Tanya Das 《FEBS letters》2014
Tumor-suppressive miR-34a, a direct target of p53, has been shown to target several molecules of cell survival pathways. Here, we show that capsaicin-induced oxidative DNA damage culminates in p53 activation to up-regulate expression of miR-34a in non-small cell lung carcinoma (NSCLC) cells. Functional analyses further indicate that restoration of miR-34a inhibits B cell lymphoma-2 (Bcl-2) protein expression to withdraw the survival advantage of these resistant NSCLC cells. In such a proapoptotic cellular milieu, where drug resistance proteins are also down-regulated, p53-transactivated Bcl-2 associated X protein (Bax) induces apoptosis via the mitochondrial death cascade. Our results suggest that p53/miR-34a regulatory axis might be critical in sensitizing drug-resistant NSCLC cells. 相似文献
155.
Qian Wang Dennis W. Ashley Paul C. Dechow 《American journal of physical anthropology》2010,141(4):526-549
Understanding the mechanical features of cortical bone and their changes with growth and adaptation to function plays an important role in our ability to interpret the morphology and evolution of craniofacial skeletons. We assessed the elastic properties of cortical bone of juvenile and adult baboon mandibles using ultrasonic techniques. Results showed that, overall, cortical bone from baboon mandibles could be modeled as an orthotropic elastic solid. There were significant differences in the directions of maximum stiffness, thickness, density, and elastic stiffness among different functional areas, indicating regional adaptations. After maturity, the cortical bone becomes thicker, denser, and stiffer, but less anisotropic. There were differences in elastic properties of the corpus and ramus between male and female mandibles which are not observed in human mandibles. There were correlations between cortical thicknesses and densities, between bone elastic properties and microstructural configuration, and between the directions of maximum stiffness and bone anatomical axes in some areas. The relationships between bone extrinsic and intrinsic properties bring us insights into the integration of form and function in craniofacial skeletons and suggest that we need to consider both macroscopic form, microstructural variation, and the material properties of bone matrix when studying the functional properties and adaptive nature of the craniofacial skeleton in primates. The differences between baboon and human mandibles is at variance to the pattern of differences in crania, suggesting differences in bone adaption to varying skeletal geometries and loading regimes at both phylogenetic and ontogenetic levels. Am J Phys Anthropol, 2010. © 2009 Wiley‐Liss, Inc. 相似文献
156.
157.
Lymnaea peregra was collected at sites, predominantly from the Caha plateau, in south-west Ireland. These included sites investigated by previous workers and found to contain populations with a distinctive pattern of variation in shell-shape. Normally spired populations and non-spired ( involuta, sub-involuta ) could occur in adjacent loughs in the same watershed. The biochemical variation in some of these populations was investigated using horizontal starch-gel zone electrophoresis. Fourteen biochemical loci were investigated. Although circumscribed by difficulties in collecting and low sample numbers, the investigation showed that the pattern of variation in shell shape was still present and was not correlated or associated with the biochemical variation. While this did not support hypotheses of geographic race formation or incipient speciation, it was in agreement with the current view of variation and speciation in fresh-water pulmonates. 相似文献
158.
V. V. Baranov 《Paleontological Journal》2007,41(3):252-259
Brachiopods from the Devonian of northeastern Russia are described: Eoprokopia gen. nov., with the type species E. aequalis sp. nov. (subfamily Prokopiinae, order Orthida); Davoustia settedabanica sp. nov. and D. verkhojanica sp. nov. (family Anopliidae, order Chonetida); and Alkhovikovia gen. nov. with the type species A. libera sp. nov. and A. importuna sp. nov. and Tikhyspirifer gen. nov. with the type species T. globosus sp. nov. (subfamily Rhynchospiriferinae, order Spiriferida). 相似文献
159.
Yelin R Kot H Yelin D Fainsod A 《Differentiation; research in biological diversity》2007,75(5):393-403
Fetal alcohol spectrum disorder (FASD) is the combination of developmental, morphological, and neurological defects that result from exposing human embryos to ethanol (EtOH). Numerous embryonic structures are affected, leading to a complex viable phenotype affecting among others, the anterior/posterior axis, head, and eye formation. Recent studies have provided evidence suggesting that EtOH teratogenesis is mediated in part through a reduction in retinoic acid (RA) levels, targeting mainly the embryonic organizer (Spemann's organizer) and its subsequent functions. EtOH-treated Xenopus embryos were subjected to an analysis of gene expression patterns. Analysis of organizer-specific genes revealed a transient delay in the invagination of gsc- and chordin-positive cells that eventually reach their normal rostro-caudal position. Dorsal midline genes show defects along the rostro-caudal axis, lacking either their rostral (Xbra and Xnot2) or caudal (FoxA4b and Shh) expression domains. Head-specific markers like Otx2, en2, and Shh show abnormal expression patterns. Otx2 exhibits a reduction in expression levels, while en2 becomes restricted along the dorsal/ventral axis. During neurula stages, Shh becomes up-regulated in the rostral region and it is expressed in an abnormal pattern. These results and histological analysis suggest the existence of malformations in the brain region including a lack of the normal fore brain ventricle. An increase in the size of both the prechordal plate and the notochord was observed, while the spinal cord is narrower. The reduction in head and eye size was accompanied by changes in the eye markers, Pax6 and Tbx3. Our results provide evidence for the early molecular changes induced by EtOH exposure during embryogenesis, and may explain some of the structural changes that are part of the EtOH teratogenic phenotype also in FASD individuals. 相似文献
160.
The selective pressures associated with flight are significant factors in shaping the morphology of volant forms. Tropical seabirds are of particular interest because of their long foraging bouts, which can last hundreds of kilometers in search of unpredictable (spatially and temporally) resources. Here, we contrast wing loading (WL), aspect ratio (AR), and planform shape among five pelecaniform seabirds and correlate morphological diversity with known differences in flight strategies. Overall, WL and AR scaled with body mass. The Great Frigratebird had lower WL than that predicted, whereas the Red-tailed Tropicbird had higher WL than that predicted. The tropicbird also exhibited a lower AR than that predicted. Visualization of planform shape was accomplished by using Thin-plate spline relative warp analysis (TPS/RWA), and three major regions of variations were discovered: wing base, mid-wing, and distal wing/wing tip. As expected, the three boobies were more similar than either the tropicbird or the frigatebird. The tropicbird had a broader distal wing and more rounded wing tip, associated with its greater use of flapping flight. The frigatebird showed the greatest deviation in the distal wing and wing tip associated with the high maneuverability required for aerial pursuit and kleptoparasitism. By using TPS/RWA, important differences were detected in planform shape that would have otherwise gone unnoticed when using only WL and AR. These differences correlated strongly with parameters such as maneuverability, flapping, and soaring flight. 相似文献