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91.
92.
Iván González-Chavarría Rita P. Cerro Natalie P. Parra Felipe A. Sandoval Felipe A. Zu?iga Valeska A. Omazábal Liliana I. Lamperti Silvana P. Jiménez Edelmira A. Fernandez Nicolas A. Gutiérrez Federico S. Rodriguez Sergio A. Onate Oliberto Sánchez Juan C. Vera Jorge R. Toledo 《PloS one》2014,9(8)
Altered expression and function of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) has been associated with several diseases such as endothelial dysfunction, atherosclerosis and obesity. In these pathologies, oxLDL/LOX-1 activates signaling pathways that promote cell proliferation, cell motility and angiogenesis. Recent studies have indicated that olr1 mRNA is over-expressed in stage III and IV of human prostatic adenocarcinomas. However, the function of LOX-1 in prostate cancer angiogenesis remains to be determined. Our aim was to analyze the contribution of oxLDL and LOX-1 to tumor angiogenesis using C4-2 prostate cancer cells. We analyzed the expression of pro-angiogenic molecules and angiogenesis on prostate cancer tumor xenografts, using prostate cancer cell models with overexpression or knockdown of LOX-1 receptor. Our results demonstrate that the activation of LOX-1 using oxLDL increases cell proliferation, and the expression of the pro-angiogenic molecules VEGF, MMP-2, and MMP-9 in a dose-dependent manner. Noticeably, these effects were prevented in the C4-2 prostate cancer model when LOX-1 expression was knocked down. The angiogenic effect of LOX-1 activated with oxLDL was further demonstrated using the aortic ring assay and the xenograft model of tumor growth on chorioallantoic membrane of chicken embryos. Consequently, we propose that LOX-1 activation by oxLDL is an important event that enhances tumor angiogenesis in human prostate cancer cells. 相似文献
93.
Vassiliki Lalioti Silvia Vergarajauregui Ignacio V. Sandoval 《Molecular membrane biology》2013,30(4):257-264
The trafficking of the insulin-sensitive glucose transporter, GLUT4, is the paradigm of how cells control the movement of membrane proteins through intricate pathways of transport in response to external stimuli, and how, by doing so, regulate their function. The GLUT4 intracellularly sequestered in resting adipocytes and muscle cells becomes exposed on their surface in response to an increase in insulin levels and muscle contraction, where it facilitates glucose uptake. Ceasing of the stimuli is followed by endocytosis of the GLUT4 molecules exposed on the plasma membrane and their recycling to the original stores, where they are retained. This review discusses current understanding of the organelles that host GLUT4 and the motifs that mediate its trafficking. 相似文献
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Francisco J. García-De León Andrés I. Hernández Sandoval Fernando Contreras-Catala Laura Sánchez-Velasco Gorgonio Ruiz-Campos 《Environmental Biology of Fishes》2018,101(1):167-180
A priority issue in ecology and biogeography is understanding the patterns in species diversity and the causal factors of their distribution, which allows the generation of information for conservation strategies. The longitudinal distribution of fishes and their relationships with environmental variables were studied in the Guayalejo-Río Tamesí system (northeastern Mexico) from February 2000 to July 2001. A total of 5918 fish were caught in 27 collections along an altitudinal gradient in the main river course, from high mountain (1500 masl) to coastal plain near Tampico. Forty-three native and five exotic species, belonging to 35 genera in 23 families, were identified. Cluster analyses identified four major fish habitats in the river system. A distinctive euryhaline marine fish habitat (1) occurs near the mouth with native and two exotic species. Two other habitats consist essentially of freshwater fish species that are distributed along the longitudinal gradient. One of these habitats (habitat 4) shows greater diversity, as per the Shannon index value, and also includes amphidromous fish, in addition to two exotic freshwater fish; the other (habitat 2) includes freshwater, euryhaline and three exotic species. The changes in the frequency of occurrence and the abundance of Gambusia vittata, Astyanax mexicanus, and Xiphophorus variatus contribute to explaining differences between these habitats. Another habitat (3) is represented by two sampling sites located near the mouth and consist of freshwater and euryhaline fish and three exotic cyprinids with broad salinity tolerance. The low abundance and richness of exotic species suggest little impact on native fish fauna in this river. The fish assemblage of the Guayalejo-Tamesí river system species changes along a longitudinal gradient with the addition, replacement and presence of indicator species. Upstream fish fauna is mostly composed of freshwater species, some of them generalists that inhabit the entire longitudinal gradient, others that are restricted to certain sites, and the remainder of species is an assemblage composed of a mixture of euryhaline freshwater and marine species near the mouth. 相似文献
96.
Pedro Jimenez‐Sandoval Ezequiel A. Madrigal‐Carrillo Hugo A. Santamaría‐Suárez Daniel Maturana Itzel Rentería‐González Claudia G. Benitez‐Cardoza Alfredo Torres‐Larios Luis G. Brieba 《Proteins》2018,86(7):802-812
Antibodies recognize protein targets with great affinity and specificity. However, posttranslational modifications and the presence of intrinsic disulfide‐bonds pose difficulties for their industrial use. The immunoglobulin fold is one of the most ubiquitous folds in nature and it is found in many proteins besides antibodies. An example of a protein family with an immunoglobulin‐like fold is the Cysteine Protease Inhibitors (ICP) family I42 of the MEROPs database for protease and protease inhibitors. Members of this protein family are thermostable and do not present internal disulfide bonds. Crystal structures of several ICPs indicate that they resemble the Ig‐like domain of the human T cell co‐receptor CD8α As ICPs present 2 flexible recognition loops that vary accordingly to their targeted protease, we hypothesize that members of this protein family would be ideal to design peptide aptamers that mimic protein‐protein interactions. Herein, we use an ICP variant from Entamoeba histolytica (EhICP1) to mimic the interaction between p53 and MDM2. We found that a 13 amino‐acid peptide derived from p53 can be introduced in 2 variable loops (DE, FG) but not the third (BC). Chimeric EhICP1‐p53 form a stable complex with MDM2 at a micromolar range. Crystal structure of the EhICP1‐p53(FG)‐loop variant in complex with MDM2 reveals a swapping subdomain between 2 chimeric molecules, however, the p53 peptide interacts with MDM2 as in previous crystal structures. The structural details of the EhICP1‐p53(FG) interaction with MDM2 resemble the interaction between an antibody and MDM2. 相似文献
97.
98.
Inactivation and Degradation of CuZn-SOD by Active Oxygen Species in Wheat Chloroplasts Exposed to Photooxidative Stress 总被引:8,自引:0,他引:8
Casano Leonardo M.; Gomez Leonardo D.; Lascano Hernan R.; Gonzalez Claudio A.; Trippi Victorio S. 《Plant & cell physiology》1997,38(4):433-440
Changes in CuZn-SOD actvity and content in isolated wheat chloroplastsunder the light, and the involvement of protease(s) and/or activeoxygen species in this process were studied. Both SOD activityand content decayed with exposure time to photooxidative stress.Ascorbate, a H2O2 scavenger, prevented photooxidation-associatedinactivation of SOD, while benzoate, a OH scavenger, preventedSOD degradation. Wheat chloroplasts incubated in the dark didnot hydrolyze exogenous or endogenous SOD, either H2O2-pretreatedor not. Protease inhibitors did not prevent SOD degradationunder photooxidative treatment, suggesting that plastid protease(s)did not participate in this process. Purified chloroplast CuZn-SODwas exposed to H2O2 and or OH-generating systems. had no effect on either SOD activity or stability (estimated bynative PAGE). H2O2 up to 700µM inhibited SOD in a dose-dependentmanner and induced charge/mass changes as seen by native PAGE.OH also reduced SOD activity by inducing its fragmentation.High levels of active oxygen, as can be generated under strongstress conditions, could directly inactivate and degrade chloroplasticSOD.
1 Present address: Departamento de Biología Vegetal,Univer-sidad de Alcalá de Henares, Alcalá de Henares,E-28871 Madrid, Spain 相似文献
99.
We used phylogenetic and ecological information to study the evolution of host‐plant specialization and colour polymorphism in the genus Timema, which comprises 14 species of walking‐sticks that are subject to strong selection for cryptic coloration on their host‐plants. Phylogenetic analysis indicated that this genus consists of three main lineages. Two of the lineages include highly generalized basal species and relatively specialized distal species, and one of the lineages comprises four specialized species. We tested for phylogenetic conservatism in the traits studied via randomizing host‐plant use, and the four basic Timema colour patterns, across the tips of the phylogeny, and determining if the observed number of inferred changes was significantly low compared to the distribution of numbers of inferred changes expected under the null model. This analysis showed that (1) host‐plant use has evolved nonrandomly, such that more closely related species tend to use similar sets of hosts and (2) colour pattern evolution exhibits considerable lability. Inference of ancestral states using maximum parsimony, under four models for the relative ease of gain and loss of plant hosts or colour morphs, showed that (1) for all models with gains of host‐plants even marginally more difficult than losses, and for most optimizations with gains and losses equally difficult, the ancestral Timema were generalized, feeding on the chaparral plants Ceanothus and Adenostoma and possibly other taxa, and (2) for all models with gains of colour morphs more difficult than losses, the ancestral Timema were polymorphic for colour pattern. Generation of null distributions of inferred ancestral states showed that the maximum‐parsimony inference of host‐plant generalization was most robust for the most speciose of the three main Timema lineages. Ancestral states were also inferred using maximum likelihood, after recoding host‐plant use and colour polymorphism as dichotomous characters. Likelihood analyses provided some support for inference of generalization in host‐plant use at ancestral nodes of the two lineages exhibiting mixtures of generalists and specialists, although levels of uncertainty were high. By contrast, likelihood analysis did not estimate ancestral colour morph patterns with any confidence, due to inferred rates of change that were high with respect to speciation rates. Information from biogeography, floristic history and the timing of diversification of the genus are compatible with patterns of inferred ancestral host‐plant use. Diversification in the genus Timema appears to engender three main processes: (1) increased specialization via loss of host‐plants, (2) retention of the same, single, host‐plant and (3) shifts to novel hosts to which lineages were ‘preadapted’ in colour pattern. Our evidence suggests that the radiation of this genus has involved multiple evolutionary transitions from individual‐level specialization (multiple‐niche polymorphism) to population‐level and species‐level specialization. Ecological studies of Timema suggest that such transitions are driven by diversifying selection for crypsis. This paper provides the first phylogeny‐based evidence for the macroevolutionary importance of predation by generalist natural enemies in the evolution of specialization. 相似文献
100.
Patterns of CCR5, CXCR4, and CCR3 Usage by Envelope Glycoproteins from Human Immunodeficiency Virus Type 1 Primary Isolates 总被引:6,自引:2,他引:4
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Hernan A. Bazan Ghalib Alkhatib Christopher C. Broder Edward A. Berger 《Journal of virology》1998,72(5):4485-4491
Coreceptor usage by Envs from diverse primary human immunodeficiency virus type 1 isolates was analyzed by a vaccinia virus-based expression and assay system. Usage of recombinant CCR5 and CXCR4 correlated closely with fusogenicity toward macrophages and T-cell lines expressing endogenous coreceptors. Surprisingly, recombinant CCR3 was utilized by most primary and T-cell-line-adapted Envs. Endogenous CXCR4 in macrophages was functional as a coreceptor. 相似文献