排序方式: 共有122条查询结果,搜索用时 31 毫秒
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Ricardo Calado Ainhoa O. Olaguer-Feliú Juan Ignacio González-Gordillo Henrique Queiroga 《Marine and Freshwater Behaviour and Physiology》2013,45(5):329-341
During the mass settlement events of brachyuran crabs, there is a significant chance of density-dependent injury in the megalopae (last larval stage) because cannibalism can occur by larger conspecifics. Laboratory observations revealed that the appendages that are more prone to injury are eyestalks, as well as first (P1) and fifth (P5) pereiopods. The ability of Carcinus maenas megalopae to autotomize these structures and the effect of such injuries in their feeding ability and metamorphosis were investigated. All tested specimens were able to autotomize one or both of their P1 and P5, but not their eyestalks. Megalopae missing a single P1, as well as one or both P5, were able to capture and ingest prey, as well as intact specimens. Megalopae with either P1 and P5 appendages or at least one damaged eyestalk failed to ingest sufficient food to reach the nutritional threshold required to successfully metamorphose. 相似文献
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Carlos Oscar Sánchez Sorzano Alberto Pascual-Montano Ainhoa Sánchez de Diego Carlos Martínez-A Karel H.M. van Wely 《Cell cycle (Georgetown, Tex.)》2013,12(13):2016-2023
The acquisition of massive but localized chromosome translocations, a phenomenon termed chromothripsis, has received widespread attention since its discovery over a year ago. Until recently, chromothripsis was believed to originate from a single catastrophic event, but the molecular mechanisms leading to this event are yet to be uncovered. Because a thorough interpretation of the data are missing, the phenomenon itself has wrongly acquired the status of a mechanism used to justify many kinds of complex rearrangements. Although the assumption that all translocations in chromothripsis originate from a single event has met with criticism, satisfactory explanations for the intense but localized nature of this phenomenon are still missing. Here, we show why the data used to describe massive catastrophic rearrangements are incompatible with a model comprising a single event only and propose a molecular mechanism in which a combination of known cellular pathways accounts for chromothripsis. Instead of a single traumatic event, the protection of undamaged chromosomes by telomeres can limit repetitive breakage-fusion-bridge events to a single chromosome arm. Ultimately, common properties of chromosomal instability, such as aneuploidy and centromere fission, might establish the complex genetic pattern observed in this genomic state. 相似文献
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In order to evaluate if snorkeling had significant effects on coral community structure, three different coral reefs (Madrizquí, Pelona de Rabusquí and Crasquí) located at Archipelago Los Roques National Park, Venezuela, were surveyed. For each site, the coral community structure of two different areas, one subjected to intense snorkeling use (FB) and other not frequently used (PFB), were compared. Community structure was determined with 1 m2-quadrants and 20 m-long transects. These communities were described in terms of species richness, diversity (Shannon-Wiener) and evenness indexes, live and dead coral cover and cover of other organisms (sponges, octocorals and algae). Comparisons within sites were performed with a Kruskall-Wallis test. A total of 24 species of scleractinian corals were found. Live coral cover ranged from 29.9% +/- 26.43 (Crasquí) to 34.55% +/- 6.43 (Madrizquí), while dead coral cover ranged from 32.51% +/- 2.86 (Madrizquí) to 60.78% +/- 21.3 (Pelona de Rabusquí). The PFB areas showed higher live coral cover compared to FB areas; however, significant differences were only found in Crasquí and Pelona de Rabusquí (p < 0.05). Species richness, diversity and evenness were variable and no trends were observed between FB and PFB areas. The frequency of both damaged and diseased colonies were low (< 1%), most damages observed were natural (parrotfish predation). Damages caused by divers such as fin impacts, were not found at the reefs studied. These results suggest that, currently, diving pressure is not as high to cause massive loses of live coral cover in these reefs. However, the lack of strict controls for these activities might produce long-term changes in the structure of these coral communities. 相似文献
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M. Rosa Bernal-López Ainhoa Rípodas Paloma Aragoncillo Manuel Gil Aguado Francisco Javier Serrano Hernando Francisco J. Tinahones Ricardo Gómez-Huelgas Arturo Fernández-Cruz 《Process Biochemistry》2009,44(11):1231-1236
Endothelin-1 (ET-1) is a potent vasoconstrictor peptide that can modulate the behaviour of vascular smooth muscle cells and thus impact on the development of human atherosclerosis. Circulating plasma levels of ET-1 were measured from 82 patients with ischemic cardiomyopathy (ICM) and 42 healthy controls. A significant increase was found in plasma levels of ET-1 in the patients compared to the controls. These circulating levels of ET-1 were greater in patients with diabetes or involvement of several territories. Gene expression of pre-proET-1 and its receptors ETA and ETB was analyzed in the atheromatous plaques from carotid arteries (n = 8) and the internal mammary artery (IMA) (n = 8). Our group observed an increase in pre-proET-1 and ETA in IMA compared with the atheromatous plaques. Immunohistochemical studies in the atherosclerotic plaque showed that the expression of ET-1 was greater in the areas where the macrophages and lipid nucleus were located.Our findings in this group of patients with symptomatic vascular disease suggest that the endothelin system may play an important role in atherothrombosis. 相似文献
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Ferrer B Bermúdez-Silva FJ Bilbao A Alvarez-Jaimes L Sanchez-Vera I Giuffrida A Serrano A Baixeras E Khaturia S Navarro M Parsons LH Piomelli D Rodríguez de Fonseca F 《The Biochemical journal》2007,408(1):97-104
FgFtr1 and FgFtr2 are putative iron permeases, and FgFet1 and FgFet2 are putative ferroxidases of Fusarium graminearum. They have high homologies with iron permease ScFtr1 and ferroxidase ScFet3 of Saccharomyces cerevisiae at the amino acid level. The genes encoding iron permease and ferroxidase were localized to the same chromosome in the manner of FgFtr1/FgFet1 and FgFtr2/FgFet2. The GFP (green fluorescent protein)-fused versions of FgFtr1 and FgFtr2 showed normal functions when compared with FgFtr1 and FgFtr2 in an S. cerevisiae system, and the cellular localizations of FgFtr1 and FgFtr2 in S. cerevisiae depended on the expression of their putative ferroxidase partners FgFet1 and FgFet2 respectively. Although FgFtr1 was found on the plasma membrane when FgFet1 and FgFtr1 were co-transformed in S. cerevisiae, most of the FgFtr1 was found in the endoplasmic reticulum compartment when co-expressed with FgFet2. Furthermore, FgFtr2 was found on the vacuolar membrane when FgFet2 was co-expressed. From the two-hybrid analysis, we confirmed the interaction of FgFtr1 and FgFet1, and the same result was found between FgFtr2 and FgFet2. Iron-uptake activity also depended on the existence of the respective partner. Finally, the FgFtr1 and FgFtr2 were found on the plasma and vacuolar membrane respectively, in F. graminearum. Taken together, these results strongly suggest that FgFtr1 and FgFtr2 from F. graminearum encode the iron permeases of the plasma membrane and vacuolar membrane respectively, and require their specific ferroxidases to carry out normal function. Furthermore, the present study suggests that the reductive iron-uptake system is conserved from yeast to filamentous fungi. 相似文献
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Mielgo A Brondani V Landmann L Glaser-Ruhm A Erb P Stupack D Günthert U 《Apoptosis : an international journal on programmed cell death》2007,12(11):2051-2061
The transmembrane receptor CD44 conveys important signals from the extracellular microenvironment to the cytoplasm, a phenomena
known as “outside-in” signaling. CD44 exists as several isoforms that result from alternative splicing, which differ only
in the extracellular domain but yet exhibit different activities. CD44 is a binding partner for the membrane-cytoskeleton
cross-linker protein ezrin. In this study, we demonstrate that only CD44 standard (CD44s) colocalizes and interacts with the
actin cross-linkers ezrin and moesin using well-characterized cell lines engineered to express different CD44 isoforms. Importantly,
we also show that the association CD44s-ezrin-actin is an important modulator of Fas-mediated apoptosis. The results highlight
a mechanism by which signals from the extracellular milieu regulate intracellular signaling activities involved in programmed
cell death.
Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users. 相似文献
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The in vitro and in vivo characterization of cell-loaded immobilization devices is an important challenge in cell encapsulation technology for the long-term efficacy of this approach. In the present paper, alginate-poly-l-lysine-alginate (APA) microcapsules containing erythropoietin (Epo)-secreting C2C12 myoblasts have been elaborated, characterized, and tested both in vitro and in vivo. High mechanical and chemical resistance of the elaborated microcapsules was observed. Moreover, the in vitro cultured encapsulated cells released 81.9 +/- 8.2 mIU/mL/24 h (by 100 cell-loaded microcapsules) by day 7, reaching the highest peak at day 21 (161.7 +/- 0.9 mIU/mL/24 h). High and constant hematocrit levels were maintained over 120 days after a single subcutaneous administration of microcapsules and lacking immunosuppressive protocols. No major host reaction was observed. On the basis of the results obtained in our study, cell encapsulation technology might be considered a suitable therapeutic strategy for the long-term delivery of biologically active products, such as Epo. 相似文献