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981.
Yang Li Lina He Ni Zeng Divya Sahu Enrique Cadenas Colin Shearn Wei Li Bangyan L. Stiles 《The Journal of biological chemistry》2013,288(35):25007-25024
Mitochondrial abnormalities are associated with cancer development, yet how oncogenic signals affect mitochondrial functions has not been fully understood. In this study, we investigate the relationship between mitochondrial alterations and PI3K/protein kinase B (AKT) signaling activation using hepatocytes and liver tissues as our experimental models. We show here that liver-specific deletion of Pten, which leads to activation of PI3K/AKT, is associated with elevated oxidative stress, increased mitochondrial mass, and augmented respiration accompanied by enhanced glycolysis. Consistent with these observations, estrogen-related receptor α (ERRα), an orphan nuclear receptor known for its role in mitochondrial biogenesis, is up-regulated in the absence of phosphatase and tensin homolog deleted on chromosome 10 (PTEN). Our pharmacological and genetic studies show that PI3K/AKT activity regulates the expression of ERRα and mitochondrial biogenesis/respiration. Furthermore, cAMP-response element-binding protein, as a downstream target of AKT, plays a role in the regulation of ERRα, independent of PKA signaling. ERRα regulates reactive oxygen species production, and ERRα knockdown attenuates proliferation and colony-forming potential in Pten-null hepatocytes. Finally, analysis of clinical datasets from liver tissues showed a negative correlation between expressions of ERRα and PTEN in patients with liver cancer. Therefore, this study has established a previously unrecognized link between a growth signal and mitochondrial metabolism. 相似文献
982.
983.
Dulce Figueiras‐Fierro Juan José Acevedo Pablo Martínez‐López Jessica Escoffier Francisco V. Sepúlveda Enrique Balderas Gerardo Orta Pablo E. Visconti Alberto Darszon 《Journal of cellular physiology》2013,228(3):590-601
Mammalian sperm must undergo a maturational process, named capacitation, in the female reproductive tract to fertilize the egg. Sperm capacitation is regulated by a cAMP/protein kinase A (PKA) pathway and involves increases in intracellular Ca2+, pH, Cl?, protein tyrosine phosphorylation, and in mouse and some other mammals a membrane potential hyperpolarization. The cystic fibrosis transmembrane conductance regulator (CFTR), a Cl? channel modulated by cAMP/PKA and ATP, was detected in mammalian sperm and proposed to modulate capacitation. Our whole‐cell patch‐clamp recordings from testicular mouse sperm now reveal a Cl? selective component to membrane current that is ATP‐dependent, stimulated by cAMP, cGMP, and genistein (a CFTR agonist, at low concentrations), and inhibited by DPC and CFTRinh‐172, two well‐known CFTR antagonists. Furthermore, the Cl? current component activated by cAMP and inhibited by CFTRinh‐172 is absent in recordings on testicular sperm from mice possessing the CFTR ΔF508 loss‐of‐function mutation, indicating that CFTR is responsible for this component. A Cl? selective like current component displaying CFTR characteristics was also found in wild type epididymal sperm bearing the cytoplasmatic droplet. Capacitated sperm treated with CFTRinh‐172 undergo a shape change, suggesting that CFTR is involved in cell volume regulation. These findings indicate that functional CFTR channels are present in mouse sperm and their biophysical properties are consistent with their proposed participation in capacitation. J. Cell. Physiol. 228: 590–601, 2013. © 2012 Wiley Periodicals, Inc. 相似文献
984.
Maritza Sepúlveda Doris Oliva L. René Duran Alejandra Urra Susana N. Pedraza Patrícia Majluf Natalie Goodall Enrique A. Crespo 《Oecologia》2013,171(4):809-817
We tested the validity of Bergmann’s rule and Rosenzweig’s hypothesis through an analysis of the geographical variation of the skull size of Otaria flavescens along the entire distribution range of the species (except Brazil). We quantified the sizes of 606 adult South American sea lion skulls measured in seven localities of Peru, Chile, Uruguay, Argentina, and the Falkland/Malvinas Islands. Geographical and environmental variables included latitude, longitude, and monthly minimum, maximum, and mean air and ocean temperatures. We also included information on fish landings as a proxy for productivity. Males showed a positive relationship between condylobasal length (CBL) and latitude, and between CBL and the six temperature variables. By contrast, females showed a negative relationship between CBL and the same variables. Finally, female skull size showed a significant and positive correlation with fish landings, while males did not show any relationship with this variable. The body size of males conformed to Bergmann’s rule, with larger individuals found in southern localities of South America. Females followed the converse of Bergmann’s rule at the intraspecific level, but showed a positive relationship with the proxy for productivity, thus supporting Rosenzweig’s hypothesis. Differences in the factors that drive body size in females and males may be explained by their different life-history strategies. Our analyses demonstrate that latitude and temperature are not the only factors that explain spatial variation in body size: others such as food availability are also important for explaining the ecogeographical patterns found in O. flavescens. 相似文献
985.
Enrique Peñalver 《法国昆虫学会纪事》2013,49(1-2):88-99
Mesozoic orthopterans of the family Elcanidae are reported (as nymphs) in amber, from the latest Albian-Cenomanian of northern Myanmar and the Albian of northern Spain. Four distinct new species in two new genera occur, Burmelcana longirostris n. gen, n. sp. in amber from Myanmar and Hispanelcana arilloi n. gen, n. sp., H. alavensis n. sp. and H. lopezvallei n. sp. from Spanish amber. Detailed preservation reveals the fine structure of the tibial spurs and spines that are so distinctive to Elcanidae, as well as details of the abdominal styli, cerci, tarsomeres, and mouthparts. Elcanidae and their stem group, Permelcanidae, are known from the Early Permian to the Early Cretaceous (Aptian), so the amber fossils represent the latest known occurrence of this clade. 相似文献
986.
Adolfo Vásquez Trujillo Angélica E González Reina Agustín Góngora Orjuela Edgar Prieto Suárez Jairo Enrique Palomares Luz Stella Buitrago Alvarez 《Memórias do Instituto Oswaldo Cruz》2013,108(4):463-469
Lutzomyia antunesi has been commonly reported in outbreaks of
cutaneous leishmaniasis (CL) in the Orinoquia region of Colombia. The bionomics
of this species were studied in the municipality of Villavicencio (Meta,
Colombia). Sandflies were captured over the course of one week per month for one
year in intradomiciliary, peridomiciliary and extradomiciliary housing areas.
The captures were performed from 06:00 pm-06:00 am using CDC light traps and the
females were processed for polymerase chain reaction (PCR) to detect
Leishmania spp. A total of 22,097 specimens and 19 species
were captured of which Lu. antunesi (89%) and Lutzomyia
walkeri (5%) were the most abundant. Other species recognised as
anthropophilic (Lutzomyia panamensis, Lutzomyia
gomezi, Lutzomyia flaviscutellata and
Lutzomyia fairtigi) were present in very low abundance
(< 2%). Natural infection with Leishmania spp was detected using PCR in
Lu. antunesi, Lu. panamensis and
Lu. flavicutellata, showing infection rates of 1%, 4.8% and
7.5%, respectively. The present paper provides information on various ecological
aspects of Lu. antunesi. An analysis of seasonality shows that
this species increases in abundance in the hottest months (December, January and
February), directly correlating with the maximum temperature and inversely
correlating with precipitation. The natural infection rate is associated with
the peaks of highest abundance. 相似文献
987.
María Pazos-Navarro José Antonio Del Río Ana Ortuño Pascual Romero-Espinar Enrique Correal Mercedes Dabauza 《Plant Growth Regulation》2013,70(2):123-129
The first protocol for in vitro plant regeneration from different explants of Bituminaria bituminosa, a pasture and medicinal species, has been established. Three explant types (petiole, leaflet and petiole-leaflet attachment “PLA”) cultured on media with different combinations of benzylaminopurine (BA; 5.0, 10.0 or 20.0 μM) and naphthalene acetic acid (NAA) or indole acetic acid (IAA; 0.5 or 5.0 μM) were tested for calli induction, and with 5 μM BA + 0.5 μM NAA or IAA for shoot development. The average number of shoots (≥5 mm) per callus depended on the explant type and the calli induction medium. The highest average number of shoots per callus was achieved by culturing leaflet and PLA explants on 5 μM IAA + 10 μM BA for calli induction and on 0.5 μM IAA + 5 μM BA for shoot development, and by culturing petiole explants on 0.5 μM NAA + 10 μM BA followed by a second culture on 0.5 μM NAA + 5 μM BA. The highest frequency of shoot rooting was achieved with 10.0 μM NAA and 1.0 μM gibberellic acid (GA3). Rooted plants were acclimatised in a culture chamber, reaching 96 % survival. Acclimatised plants were transferred to a greenhouse and finally to the field, reaching 100 % survival. The furanocoumarin (FC) accumulation was evaluated in organogenic calli, in vitro shoots, ex vitro plants in the greenhouse and in ex vitro plants in the field (after 1 and 4 months of acclimatisation). The content of FCs depended on the plant material evaluated, being higher in ex vitro plants in the field (up to 9,824 μg g?1 DW total FC) and lowest in organogenic calli (up to 50 μg g?1 DW total FC). This effect may be due to cell organization, longer exposure to environmental factors and the developmental stage. 相似文献
988.
Viviana Dalamón M. Florencia Wernert Vanesa Lotersztein Patricio O. Craig Raúl Reynoso Diamante María E. Barteik Carlos Curet Bibiana Paoli Enrique Mansilla Ana Belén Elgoyhen 《Molecular biology reports》2013,40(12):6945-6955
This paper presents a mutation as well as a genotype–phenotype analysis of the GJB2 and GJB6 genes in 476 samples from non-syndromic unrelated Argentinean deaf patients (104 familial and 372 sporadic cases). Most of them were of prelingual onset (82 %) and 27 % were cochlear implanted. Variation of sequences was detected in 171 of the 474 patients (36 %). Overall, 43 different sequence variations were identified in GJB2 and GJB6. Four of them are reported for the first time in GJB2: c.233dupG, p.Ala78Ser, p.Val190Asp and p.Cys211Tyr. Mutations in GJB6 were detected in 3 % of patients [nine del(GJB6-D13S1830) and three del(GJB6-D13S1854)]. Of the 43 different variations identified in GJB2, 6 were polymorphisms and of the others, 10 (27 %) were truncating and 27 (73 %) were nontruncating. Patients with two truncating mutations had significantly worse hearing impairment than all other groups. Moderate phenotypes were observed in a group of patients carrying biallelic mutations (23 %). This work shows the high prevalence of GJB2 mutations in the Argentinean population and presents an analysis of moderate phenotypes in our cohort. 相似文献
989.
Leonardo O. Alvarado-Cárdenas Enrique Martínez-Meyer Teresa P. Feria Luis E. Eguiarte Héctor M. Hernández Guy Midgley Mark E. Olson 《Annals of botany》2013,111(6):1125-1138
Background and Aims
Convergent evolution is invoked to explain similarity between unrelated organisms in similar environments, but most evaluations of convergence analyse similarity of organismal attributes rather than of the environment. This study focuses on the globular succulent plants of the Americas, the cacti, and their counterparts in Africa in the ice-plant, spurge and milkweed families. Though often held up as paragons of convergent morphological evolution, the environmental similarity of these plants has remained largely unexamined from a quantitative perspective.Methods
Five hotspots (centres of high species diversity of globular succulents) were selected, two in Mexico and three in South Africa. Their environments were compared using niche modelling tools, randomization tests of niche similarity and multivariate analyses to test for environmental similarity.Key Results
Although the sites selected have ‘similar’ but unrelated life forms, almost all our results highlighted more climate differences than similarities between the hotspots. Interprediction of niches within and between continents, a niche equivalence test, and MANOVA results showed significant differences. In contrast, a niche similarity test showed that the comparisons of Cuatrociénegas–Richtersveld, Huizache–Knersvlakte and Huizache–Richtersveld were similar.Conclusions
Differences in rainfall and temperature regimes and the potential effect of edaphic factors may be involved in the differences between the hotspots. In addition, differences in structure, morphology and physiology of the globular succulents may coincide with some of the climatic dissimilarities; i.e. given convergence as the evolution of similar morphologies under similar conditions, then it may be that differing environments diagnose inconspicuous morphological differences. Moreover, although fine-scale differences between sites were found, a coarser perspective shows that these sites are clearly similar as drylands with relatively moderate drought and mild temperatures, illustrating how all studies of convergence must address the issue of how similar two entities must be before they are considered convergent. 相似文献990.
Verónica Fasulo ZhiQiang Zhang Juan G. Chediack Fabricio D. Cid William H. Karasov Enrique Caviedes-Vidal 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2013,183(2):289-296
Water-soluble nutrients are absorbed by the small intestine via transcellular and paracellular processes. The capacity for paracellular absorption seems greater in fliers than in nonfliers, although that conclusion rests mainly on a comparison of flying birds and nonflying mammals because only two frugivorous bat species have been studied. Furthermore, the bats studied so far were relatively large (>85 g, compared with most bat species which are <20 g) and were not insectivores (like about 70 % of bat species). We studied the small (11 g) insectivorous bat Tadarida brasiliensis and tested the prediction that the capacity for paracellular absorption would be as high as in the other bat and avian species studied so far, well above that in terrestrial, nonflying mammals. Using standard pharmacokinetic technique, we measured the extent of absorption (fractional absorption = f) of inert carbohydrate probes: L-arabinose (MM = 150.13) absorbed exclusively by paracellular route and 3OMD-glucose (MM = 194) absorbed both paracellularly and transcellularly. As predicted, the capacity of paracellular absorption in this insectivorous bat was high (L-arabinose f = 1.03 ± 0.14) as in other frugivorous bats and small birds. Absorption of 3OMD-glucose was also complete (f = 1.09 ± 0.17), but >80 % was accounted for by paracellular absorption. We conclude that passive paracellular absorption of molecules of the size of amino acids and glucose is extensive in this bat and, generally in bats, significantly higher than that in nonflying mammals, although the exact extent can be somewhat lower or higher depending on molecule size, polarity and charge. 相似文献