Showing papers by "National University of Cuyo published in 2009"
TL;DR: Evidence is presented indicating that VAMP3 is required for the fusion between MVBs with autophagosomes to generate the amphisome, allowing the maturation of the autophagic pathway, but it does not seem to be involved in the next step, i.
443 citations
TL;DR: This review highlights the most recent advances in the understanding of the molecular machinery that participates in MVB biogenesis and regulates the interplay between autophagy and this organelle.
Abstract: In the majority of cell types, multivesicular bodies (MVBs) are a special kind of late endosomes, crucial intermediates in the internalization of nutrients, ligands and receptors through the endolysosomal system. ESCRT-0, I, II and III (endosomal sorting complex required for transport) are involved in the sorting of proteins into MVBs, generating the intraluminal vesicles. Autophagy is a lysosomal degradation pathway for cytoplasmic components such as proteins and organelles. The autophagosome, a well-characterized structure of the autophagy pathway, can fuse with endocytic structures such as MVBs to generate the amphisome. Finally, the amphisome fuses with the lysosome to degrade the material wrapped inside. Currently, clear evidence suggests that efficient autophagic degradation requires functional MVBs. This review highlights the most recent advances in our understanding of the molecular machinery that participates in MVB biogenesis and regulates the interplay between autophagy and this organelle.
423 citations
TL;DR: The results suggest that both relative species abundance and complementarity in spatiotemporal distribution contribute substantially to generate observed network patters, but that this information is by no means sufficient to predict the occurrence and frequency of pairwise interactions.
Abstract: The structure of mutualistic networks is likely to result from the simultaneous influence of neutrality and the constraints imposed by complementarity in species phenotypes, phenologies, spatial distributions, phylogenetic relationships, and sampling artifacts. We develop a conceptual and methodological framework to evaluate the relative contributions of these potential determinants. Applying this approach to the analysis of a plant-pollinator network, we show that information on relative abundance and phenology suffices to predict several aggregate network properties (connectance, nestedness, interaction evenness, and interaction asymmetry). However, such information falls short of predicting the detailed network structure (the frequency of pairwise interactions), leaving a large amount of variation unexplained. Taken together, our results suggest that both relative species abundance and complementarity in spatiotemporal distribution contribute substantially to generate observed network patters, but that this information is by no means sufficient to predict the occurrence and frequency of pairwise interactions. Future studies could use our methodological framework to evaluate the generality of our findings in a representative sample of study systems with contrasting ecological conditions.
358 citations
TL;DR: Fluridone diminished the growth of plants that had been well watered, in a manner similar to drought, but inoculation with Azospirillum completely reversed this effect, and the relative water content of the F-treated and drought-stressed plants was significantly lower.
Abstract: Azospirillum spp. are plant growth promoting bacteria (PGPB) that enhance growth by several mechanisms, including the production of phytohormones such as abscisic acid (ABA), indole-3-acetic acid (...
278 citations
TL;DR: The results suggest that the defence system of grape leaf tissues against UV-B is activated byUV-B irradiation with ABA acting downstream in the signalling pathway, as assessed by ion leakage.
Abstract: We investigated the interactions of abscisic acid (ABA) in the responses of grape leaf tissues to contrasting ultraviolet (UV)-B treatments. One-year-old field-grown plants of Vitis vinifera L. were exposed to photosynthetically active radiation (PAR) where solar UV-B was eliminated by using polyester filters, or where PAR was supplemented with UV-B irradiation. Treatments combinations included weekly foliar sprays of ABA or a water control. The levels of UV-B absorbing flavonols, quercetin and kaempferol were significantly decreased by filtering out UV-B, while applied ABA increased their content. Concentration of two hydroxycinnamic acids, caffeic and ferulic acids, were also increased by ABA, but not affected by plus UV-B (+UV-B) treatments. Levels of carotenoids and activities of the antioxidant enzymes, catalase, ascorbate peroxidase and peroxidase were elevated by +ABA treatments, but only if +UV-B was given. Cell membrane beta-sitosterol was enhanced by ABA independently of +UV-B. Changes in photoprotective compounds, antioxidant enzymatic activities and sterols were correlated with lessened membrane harm by UV-B, as assessed by ion leakage. Oxidative damage expressed as malondialdehyde content was increased under +UV-B treatments. Our results suggest that the defence system of grape leaf tissues against UV-B is activated by UV-B irradiation with ABA acting downstream in the signalling pathway.
188 citations
TL;DR: Stromal caveolin-1 expression may be a potential therapeutic target and a valuable prognostic indicator of breast cancer progression and the onset of mammary tumors driven by Her2/neu overexpression was accelerated in mice lacking caveolini-1, thereby supporting the observation that the presence of caveolin1 in the tumor microenvironment modulates tumor development.
Abstract: Caveolin-1 has been linked to tumor progression and clinical outcome in breast cancer, but a clear resolution of its role as a prognostic marker is lacking. We assessed caveolin-1 levels in normal breast tissue and two breast cancer cohorts for which outcome data were available. We found that caveolin-1 was not expressed in normal breast luminal epithelium but was present in the epithelial compartment of some tumors. We found no association between caveolin-1 expression in the epithelial compartment and clinical outcome. However, high levels of caveolin-1 in the stromal tissue surrounding the tumor, rather than within tumor cells, associated strongly with reduced metastasis and improved survival (P < 0.0001). The onset of mammary tumors driven by Her2/neu overexpression was accelerated in mice lacking caveolin-1, thereby supporting the observation that the presence of caveolin-1 in the tumor microenvironment modulates tumor development. These studies suggest that stromal caveolin-1 expression may be a potential therapeutic target and a valuable prognostic indicator of breast cancer progression.
188 citations
TL;DR: The use of monodasylcadaverine (MDC) and DQ-BSA and the advantages of the utilization of these two methods to characterize the autophagy pathway are discussed.
Abstract: In this chapter we describe the use of monodasylcadaverine (MDC) and DQ-BSA, two practical and convenient tools to study the autophagic pathway. MDC is a lysosomotropic compound useful for the identification of autophagic vesicles by fluorescence microscopy and, in addition, to assess autophagy induction via the accumulation of MDC-labeled vacuoles. However, the increase of autophagosomes does not necessarily reflect autophagosome maturation and degradation of the sequestered materials, thus the use of DQ-BSA in conjunction with and autophagic marker is an appropriate technique to monitor the formation of the autolysosome, the degradative compartment. Therefore, here we discuss the advantages of the utilization of these two methods to characterize the autophagy pathway.
152 citations
TL;DR: Experimental diabetes showed clear signs of changes in the dentate gyrus, changes similar to those present in the aging process, in line with a reduced performance in learning and memory tests.
130 citations
TL;DR: In this paper, the authors evaluated the effects of the changes on disturbance regimes produced by different forms of land transformation on the structure and function of ecosystems of the Monte Biogeographical Province, in Argentinean arid west.
117 citations
TL;DR: This review has summarized the interaction between autophagy and different bacterial pathogens including those that take advantage of the host cell Autophagy, allowing successful colonization, as well as those microorganisms which are controlled by autophagic as part of the innate surveillance mechanism.
113 citations
TL;DR: A simple, efficient, innovative and environmentally friendly analytical technique was successfully applied for the first time for the extraction and preconcentration of polybrominated diphenyl ethers (PBDEs) from water samples, showing a successful robustness of the analytical methodology for determination of picogram per milliliter of PBDEs in water samples.
TL;DR: In this paper, the authors reviewed the current state of research on vegetation heterogeneity in the Monte Desert at scales varying from landscape to intra-patch and found evidence of cross-scale interactions, feedbacks, and non-linear effects such as those induced by grazing disturbance.
TL;DR: Grosse, Pablo as discussed by the authors, et al. as discussed by the authors presented a study of the relationship between mineralogia and petrologia in the context of Argentina's mining industry, focusing on the following topics:
Abstract: Fil: Grosse, Pablo. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. Division Mineralogia y Petrologia; Argentina
TL;DR: A simple microextraction technique based on room temperature ionic liquids for trace V(IV) and V(V) species separation and preconcentration in water samples was developed and successfully applied for the speciation analysis of V in tap and river water samples.
TL;DR: The method was successfully applied to the determination of mercury in river, sea, mineral and tap water samples and a certified reference material (CRM).
TL;DR: The proposed methodology was applied for the analysis of polybrominated diphenyl ethers from samples of environmental interest prior gas chromatography-mass spectrometry (GC-MS) analysis and recovered satisfactory robustness of the method for analyzing PBDEs in water samples.
TL;DR: It is proposed that SNAREs present in the plasma membrane interact withSNAREs in the protruding edge of cup-shaped invaginations of the outer acrosomal membrane to form trans complexes to generate the hybrid vesicles that are released during the acrosome reaction.
Abstract: Acrosomal exocytosis in mammalian sperm is a regulated secretion with unusual characteristics. One of its most striking features is the loss of the outer acrosomal membrane and the overlying plasma membrane as hybrid vesicles. We have reported previously in human sperm that by preventing the release of calcium from the acrosome, the exocytic process can be arrested at a stage where SNARE proteins are assembled in loose trans complexes. Transmission electron micrographs of sperm at this stage showed that the acrosomes were profusely swollen, with deep invaginations of the outer acrosomal membrane. The protruding edges of these invaginations were tightly apposed (i.e., docked) to the plasma membrane. Docking was prevented when streptolysin O-permeabilized sperm were stimulated in the presence of tetanus toxin or botulinum neurotoxin C, two SNARE-specific proteases. We propose that SNAREs present in the plasma membrane interact with SNAREs in the protruding edge of cup-shaped invaginations of the outer acrosomal membrane to form trans complexes. Fusion pore opening and expansion in this ring of apposed membranes would generate the hybrid vesicles that are released during the acrosome reaction.
TL;DR: It is proposed that Epac sits at a critical point during the exocytotic cascade after which the pathway splits into two limbs, one that assembles the fusion machinery into place and another that elicits intracellular calcium release.
TL;DR: It is shown, for the first time, that the vacuole containing T. cruzi (TcPV) is decorated by the host cell autophagic protein LC3, and live cell imaging experiments indicate that autolysosomes are recruited to parasite entry sites.
Abstract: The etiologic agent of Chagas disease, Trypanosoma cruzi, infects mammalian cells activating a signal transduction cascade that leads to the formation of its parasitophorous vacuole. Previous works have demonstrated the crucial role of lysosomes in the establishment of T. cruzi infection. In this work we have studied the possible relationship between this parasite and the host cell autophagy. We show, for the first time, that the vacuole containing T. cruzi (TcPV) is decorated by the host cell autophagic protein LC3. Furthermore, live cell imaging experiments indicate that autolysosomes are recruited to parasite entry sites. Interestingly, starvation or pharmacological induction of autophagy before infection significantly increased the number of infected cells whereas inhibitors of this pathway reduced the invasion. In addition, the absence of Atg5 or the reduced expression of Beclin 1 -- two proteins required at the initial steps of autophagosome formation -- limited parasite entry and reduced the association between TcPV and the classical lysosomal marker Lamp-1. These results indicate that mammalian autophagy is a key process that favors the colonization of T. cruzi in the host cell.
TL;DR: A review of the main outcomes of several archaeological and multidisciplinary South American projects related to this theme is presented in this article, where case-studies discussed here are all located within arid settings, and can be grouped into three broad geographic areas: Puna (or Altiplano) of northwestern Argentina, Cuyo (west-central Argentina), and southern Patagonia.
TL;DR: In conclusion, Malarguesaurus is a new and robust somphospondylian titanosauriform (Dinosauria, Sauropoda) from the Neuquen basin, Mendoza Province, Argentina that has procoelous distal caudal centra associated with pro coelous-opisthoplatyan proximal caudals.
TL;DR: In this article, the mass use of buckling restrained braces, mainly in developing countries, was discussed, and the buckling behavior of the dissipative core and the casing of the restrainer was analyzed.
TL;DR: Assessment of the carrying capacity for most of the areas and nutrient content of the components of livestock diet, the livestock intake values, the economic feasibility of the use of complementary feeds and the development of seeding technology for valuable forage resources as Trichloris crinita are included.
TL;DR: In this paper, a dislocation from a void in the plane along which the shear stresses are maximum is considered, which is a new paradigm in the initiation of void growth, which was attributed to convergent vacancy diffusion or prismatic loops by others.
Abstract: Dislocations are the most important element in our understanding of the mechanical response of metals. Their postulation in 1934 led to revolutionary advances in our ability to predict the mechanical behavior of materials. The authors recently advanced a dislocation mechanism for void growth in ductile metals. This paper reviews the analytical and atomistic calculations carried out in support of this model. The emission of shear dislocation loops, nucleated at the surface of nanosized voids, is responsible for the outward flux of matter, promoting void growth. This is a new paradigm in the initiation of void growth, which was attributed to convergent vacancy diffusion or to prismatic loops by others. The analytical treatment is based on the emission of a dislocation from a void in the plane along which the shear stresses are maximum. Molecular dynamics calculations performed for different orientations of the tensile axis show how the loops generate and expand outward. These loops involve the emission of partial dislocations and are the counterpart for voids of the Ashby geometrically necessary shear loops postulated for rigid particles. This process is demonstrated for bicrystalline and nanocrystalline copper.
TL;DR: The epigenetic nature of the observed flower abnormalities is consistent with the results and indicates that in the diploid hybrid studied, natural variation in methylation profiles of anonymous DNA sequences could be of biological significance.
Abstract: The wild potato Solanum ruiz-lealii Bruch. (2n = 2x = 24), a species of hybrid origin, is endemic to Mendoza province, Argentina. Recurrent flower malformations, which varied among inflorescences of the same plant, were observed in a natural population. These abnormalities could be the result of genomic instabilities, nucleus-cytoplasmic incompatibility or epigenetic changes. To shed some light on their origin, nuclear and mitochondrial DNA of plants with normal and plants with both normal and malformed flowers (from here on designated as plants with normal and plants with abnormal flower phenotypes, respectively) were analyzed by AFLP and restriction analyses, respectively. Also, the wide genome methylation status and the level of methylation of a repetitive sequence were studied by MSAP and Southern blots analyses, respectively. AFLP markers and restriction patterns of mitochondrial DNA did not allow the differentiation of normal from abnormal flower phenotypes. However, methylation patterns of nuclear DNA discriminated normal and abnormal flower phenotypes into two different groups, indicating that abnormal phenotypes have a similar methylation status which, in turn, was different from the methylation patterns of normal phenotypes. The abnormal flower phenotype was obtained by treating a normal plant with 5-Azacytidine, a demethylating agent, giving support to the idea of the role of DNA methylation in the origin of flower abnormalities. In addition, the variability detected for DNA methylation was greater than the detected for nucleotide sequence. The epigenetic nature of the observed flower abnormalities is consistent with the results and indicates that in the diploid hybrid studied, natural variation in methylation profiles of anonymous DNA sequences could be of biological significance.
TL;DR: In this paper, a numerical analysis of crater formation due to underground explosions is performed with a hydrocode, and a comparison with experimental results is performed in order to validate the numerical approach and prove its ability to model the crater formation.
TL;DR: A hypothetical physiologic role for histamine in memory is proposed under the standard theories of learning in experimental animals and humans.
TL;DR: Recommendations about the most suitable cultivars for fresh consumption, pharmaceutical and dehydration industry are made after finding variability in organosulfur composition, solids content, pungency and antiplatelet activity in garlic clones belonging to three EGs.
Abstract: Garlic is a vegetable mainly agamically propagated, and it has been dispersed all around the world. Garlic cultivars have been classified in different ecophysiological groups (EG) according to their bulbing requirements. The variability in organosulfur composition (ACSOs), solids content (SC), pungency (PC) and antiplatelet activity (IAA) and the correlation among these traits in garlic clones belonging to three EG was studied. We found variability for ACSOs, SC, PC and IAA between clones belonging to different EG and also among clones belonging to the same EG. Cutivars EG III presented more variability than EG IV for ACSOs, thiosulfinates, allicin and PC, while for SC, EG IV was the most variable. The correlations found suggested that IAA observed was mainly due to organosulfur composition. Finally recommendations about the most suitable cultivars for fresh consumption, pharmaceutical and dehydration industry are made.
TL;DR: In this paper, a heat transfer fin optimization for a LaNi 5 hydrogen storage container is presented, where a one-dimensional fin model is proposed in order to avoid geometrical restrictions and constrains associated to a particular technological solution.
TL;DR: This finding supports previous predictions that exons 45–55 are the optimal multiexon skipping target in antisense gene therapy to transform the severe Duchenne muscular dystrophy into the milder BMD, or even asymptomatic, phenotype.
Abstract: We report a Becker muscular dystrophy (BMD) family with one 5-year-old affected patient and a 69-year-old asymptomatic grandfather Dystrophin gene multiplex polymerase chain reaction and multiplex ligation-dependant probe amplification analysis showed that both males carried an in-frame deletion of exons 45-55 Segregation analysis revealed two additional asymptomatic boys in this family Our finding supports previous predictions that exons 45-55 are the optimal multiexon skipping target in antisense gene therapy to transform the severe Duchenne muscular dystrophy into the milder BMD, or even asymptomatic, phenotype