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81.
Regulation of dihydropyridine receptor gene expression in mouse skeletal muscles by stretch and disuse 总被引:2,自引:0,他引:2
This study examined dihydropyridine receptor (DHPR) gene expression in mouse skeletal muscles during physiological adaptations to disuse. Disuse was produced by three in vivo modelsdenervation, tenotomy, and immobilizationand DHPR 1s mRNA was measured by quantitative Northern blot. After 14-day simultaneous denervation of the soleus (Sol), tibialis anterior (TA), extensor digitorum longus (EDL), and gastrocnemius (Gastr) muscles by sciatic nerve section, DHPR mRNA increased preferentially in the Sol and TA (+1.6-fold), whereas it increased in the EDL (+1.6-fold) and TA (+1.8-fold) after selective denervation of these muscles by peroneal nerve section. It declined in all muscles (1.3- to 2.6-fold) after 14-day tenotomy, which preserves nerve input but removes mechanical tension. Atrophy was comparable in denervated and tenotomized muscles. These results suggest that factor(s) in addition to inactivity per se, muscle phenotype, or associated atrophy can regulate DHPR gene expression. To test the contribution of passive tension to this regulation, we subjected the same muscles to disuse by limb immobilization in a maximally dorsiflexed position. DHPR 1s mRNA increased in the stretched muscles (Sol, +2.3-fold; Gastr, +1.5-fold) and decreased in the shortened muscles (TA, 1.4-fold; EDL, 1.3-fold). The effect of stretch was confirmed in vitro. DHPR protein did not change significantly after 4-day immobilization, suggesting that additional levels of regulation may exist. These results demonstrate that DHPR 1s gene expression is regulated as an integral part of the adaptive response of skeletal muscles to disuse in both slow- and fast-twitch muscles and identify passive tension as an important signal for its regulation in vivo. dihydropyridine receptor mRNA; decreased use; passive tension; denervation; tenotomy; hindlimb immobilization 相似文献
82.
Kathryn A. Ayres James T. Ketchum Rogelio González-Armas Felipe Galván-Magaña Alex Hearn Fernando R. Elorriaga-Verplancken Edgar M. Hoyos-Padilla Stephen M. Kajiura 《Journal of fish biology》2021,99(5):1735-1740
Cabo Pulmo National Park was established in 1995 and has since seen a large increase in fish biomass. An unoccupied aerial vehicle (UAV) was used to survey shallow coastal habitat in which lemon sharks (Negaprion brevirostris), bull sharks (Carcharhinus leucas) and Pacific nurse sharks (Ginglymostoma unami) were recorded. Sharks were more common in the afternoon, potentially using warmer shallow areas to behaviourally thermoregulate. This study highlights UAV surveying to be a viable tool for species identification, a limitation of previous terrestrial surveys conducted in the area. 相似文献
83.
The roles of allopatric fragmentation and niche divergence in intraspecific lineage diversification in the common midwife toad (Alytes obstetricans) 下载免费PDF全文
84.
Soojung Claire Hur Tatiana Z. Brinckerhoff Christopher M. Walthers James C. Y. Dunn Dino Di Carlo 《PloS one》2012,7(10)
Passive and label-free isolation of viable target cells based on intrinsic biophysical cellular properties would allow for cost savings in applications where molecular biomarkers are known as well as potentially enable the separation of cells with little-to-no known molecular biomarkers. We have demonstrated the purification of adrenal cortical progenitor cells from digestions of murine adrenal glands utilizing hydrodynamic inertial lift forces that single cells and multicellular clusters differentially experience as they flow through a microchannel. Fluorescence staining, along with gene expression measurements, confirmed that populations of cells collected in different outlets were distinct from one another. Furthermore, primary murine cells processed through the device remained highly viable and could be cultured for 10 days in vitro. The proposed target cell isolation technique can provide a practical means to collect significant quantities of viable intact cells required to translate stem cell biology to regenerative medicine in a simple label-free manner. 相似文献
85.
Tomás-Zapico C Alvarez-García O Sierra V Vega-Naredo I Caballero B Joaquín García J Acuña-Castroviejo D Rodríguez MI Tolivia D Rodríguez-Colunga MJ Coto-Montes A 《Canadian journal of physiology and pharmacology》2006,84(2):213-220
The prevalence of liver diseases emphasizes the need of animal models to research on the mechanism of disease pathogenesis. Furthermore, most of the liver pathologies have the oxidative stress as an important component. The senescence-accelerated mouse strain SAMP8 was proposed as a valuable animal model for the study of liver diseases. To gain a better understanding of the mechanisms underlying degenerative processes in SAMP8 mice livers, we studied the oxidative-induced damage in 5-month-old SAMP8 mice and SAMR1, senescence-accelerated-resistant mice. We found profound differences in the antioxidant response to aging between sexes, with males displaying lowest levels of main antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GR) in SAMP8; whereas females had no difference in their activities, except for GR, when compared with their SAMR1 controls. The results obtained show the binomial SOD/CAT as an important factor for counteracting reactive oxygen species-dependent damage. There were not pathological differences at the morphological level between both strains, although the decay in protection against free radicals had an immediate response by increasing lipid and protein oxidative damage in SAMP8 mice liver. At 5 months, both male and female SAMP8 mice confront the oxidative stress challenge to different extents. Indeed, proteins seem to be the most vulnerable biomolecule in SAMP8 male mice. 相似文献
86.
87.
García-Villalobos H Morales-Trejo A Araiza-Piña BA Htoo JK Cervantes-Ramírez M 《Archives of animal nutrition》2012,66(4):257-270
The absorption of lysine is facilitated by leucine, but there is no information regarding the effect of crude protein, lysine and leucine levels on the expression of cationic amino acid transporters in pigs. Therefore, an experiment was conducted with 20 pigs (14.9 +/- 0.62 kg initial body weight) to evaluate the effect of two protein levels, and the content of lysine, threonine, methionine and leucine in low crude protein diets on the expression of b(0,+) and CAT-1 mRNA in jejunum, Longissimus dorsi and Semitendinosus muscles and serum concentration of amino acids. Treatments were as follows: (i) wheat-soybean meal diet, 20% crude protein (Control); (ii) wheat diet deficient in lysine, threonine and methionine (Basal diet); (iii) Basal diet plus 0.70% L-lysine, 0.27% L-threonine, 0.10% DL-methionine (Diet LTM); (iv) Diet LTM plus 0.80% L-leucine (Diet LTM + Leu). Despite the Basal diet, all diets were formulated to meet the requirements of lysine, threonine and methionine; Diet LTM + Leu supplied 60% excess of leucine. The addition of lysine, threonine and methionine in Diet LTM increased the expression of b(0,+) in jejunum and CAT-1 in the Semitendinosus and Longissiums muscles and decreased CAT-1 in jejunum; the serum concentration of lysine was also increased (p < 0.01). Further addition of L-leucine (Diet LTM + Leu) decreased the b(0,+) expression in jejunum and CAT-1 in the Longissimus dorsi muscle (p < 0.05), increased the serum concentration ofleucine and arginine and decreased the concentration of isoleucine (p < 0.05). Pigs fed the Control diet expressed less b(0,+) in jejunum, and CAT-1 in the Semitendinosus and Longissiums muscles expressed more CAT-1 in jejunum (p < 0.05) and had lower serum concentration ofisoleucine, leucine and valine (p < 0.05), but higher lysine concentrations (p < 0.01) than those fed Diet LTM. These results indicated that both, the level and the source of dietary amino acids, affect the expression of cationic amino acid transporters in pigs fed wheat-based diets. 相似文献
88.
89.
90.
Roberto Gamarra Emma Ortúñez Pablo Galán Cela Virginia Guadaño 《Plant Systematics and Evolution》2012,298(3):597-607
Seed micromorphology of 24 taxa of the genera Anacamptis and Orchis was examined under light and scanning electron microscopy. Seed qualitative characters appear very useful at the supraspecific
level in the subtribe Orchidinae. Based on our observations, the sculpturing of the periclinal walls of the medial testa cells,
the seed shape and several features of the anticlinal walls of the apical cells showed variability between the studied taxa,
with special relevance of the first character. According to this factor, we found one type of seed for Anacamptis and two for Orchis. The taxonomic value of seed coat characters is compared with the last taxonomic proposals for the genera Anacamptis and Orchis. 相似文献