Search results for "CIENCIAS NATURALES Y EXACTAS"
showing 10 items of 280 documents
New national and regional bryophyte records, 36
2013
In the moss flora of Uruguay there are recorder ten species of genus Fissidens (Matteri, 2004). Three of them (F. macrobryoides, F. prionocheilos and F. vitreo-limbatus) are species incertae because the type material for the names not was located (Purssel, 2007). As part of project "Studies on Bryophytes in the Cone Sur (Systematic and Phylogeny)" some specimens recently collected in Uruguay were determinate as Fissidens asplenioides a no previously species recorded in this country. The presence of F. asplenioides in Uruguay complete the distribution range of the species in the cone Sur (is present in Argentina, Bolivia, Brazil, Chile and Paraguay). However, within the Neotropical region th…
Genetic admixture despite ecological segregation in a North African sparrow hybrid zone (Aves, Passeriformes, Passer domesticus × Passer hispaniolens…
2019
Under different environmental conditions, hybridization between the same species might result in different patterns of genetic admixture. Particularly, species pairs with large distribution ranges and long evolutionary history may have experienced several independent hybridization events over time in different zones of overlap. In birds, the diverse hybrid populations of the house sparrow (Passer domesticus) and the Spanish sparrow (Passer hispaniolensis) provide a striking example. Throughout their range of sympatry, these two species do not regularly interbreed; however, a stabilized hybrid form (Passer italiae) exists on the Italian Peninsula and on several Mediterranean islands. The spa…
The "Tracked Roaming Transect" and distance sampling methods increase the efficiency of underwater visual censuses.
2018
Underwater visual census (UVC) is the most common approach for estimating diversity, abundance and size of reef fishes in shallow and clear waters. Abundance estimation through UVC is particularly problematic in species occurring at low densities and/or highly aggregated because of their high variability at both spatial and temporal scales. The statistical power of experiments involving UVC techniques may be increased by augmenting the number of replicates or the area surveyed. In this work we present and test the efficiency of an UVC method based on diver towed GPS, the Tracked Roaming Transect (TRT), designed to maximize transect length (and thus the surveyed area) with respect to diving …
Weak effects of geolocators on small birds: A meta-analysis controlled for phylogeny and publication bias
2020
Abstract Currently, the deployment of tracking devices is one of the most frequently used approaches to study movement ecology of birds. Recent miniaturization of light‐level geolocators enabled studying small bird species whose migratory patterns were widely unknown. However, geolocators may reduce vital rates in tagged birds and may bias obtained movement data. There is a need for a thorough assessment of the potential tag effects on small birds, as previous meta‐analyses did not evaluate unpublished data and impact of multiple life‐history traits, focused mainly on large species and the number of published studies tagging small birds has increased substantially. We quantitatively reviewe…
UVER and UV index at high altitude in Northwestern Argentina
2016
Measurements of ultraviolet erythemal radiation (UVER) made during two years at three sites located at altitudes over 1000 m a.s.l. in Northwestern Argentina (Salta, San Carlos, and El Rosal) have been used to estimate and analyze the UV Index (UVI) and the cumulative doses at these locations. For the UVER irradiance, data of January (maximum values) and June (minimum values) have been analyzed as representative of the year for all locations. The UVI reaches extreme (> 11) values in > 20% of the analyzed days in Salta (1190 m a.s.l.), while these are reached in San Carlos (1611 m a.s.l.) and El Rosal (3355 m a.s.l.) in > 40% of the analyzed days. Finally, the cumulative doses over an averag…
Bifunctional poly(acrylamide) hydrogels through orthogonal coupling chemistries
2019
Biomaterials for cell culture allowing simple and quantitative presentation of instructive cues enable rationalization of the interplay between cells and their surrounding microenvironment. Poly(acrylamide) (PAAm) hydrogels are popular 2D-model substrates for this purpose. However, quantitative and reproducible biofunctionalization of PAAm hydrogels with multiple ligands in a trustable, controlled, and independent fashion is not trivial. Here, we describe a method for bifunctional modification of PAAm hydrogels with thiol- and amine- containing biomolecules with controlled densities in an independent, orthogonal manner. We developed copolymer networks of AAm with 9% acrylic acid and 2% N-(4…
Estradiol, acting through ERα, induces endothelial non-classic renin-angiotensin system increasing angiotensin 1–7 production
2016
Intracellular renin-angiotensin system (RAS) can operate independently of the circulating RAS. Estrogens provide protective effects by modulating the RAS. Our aim was to investigate the effect of estradiol (E2) on angiotensin converting enzymes (ACE) 1 and ACE2 expression and activities in human endothelial cells (HUVEC), and the role of estrogen receptors (ER). The results confirmed the presence of active intracellular RAS in HUVEC. Physiological concentrations of E2 induced a concentration-dependent increase of ACE1 and ACE2 mRNA expression and ACE1, but not ACE2, protein levels. ACE1 and ACE2 enzymatic activities were also induced with E2. These effects were mediated through ERα activati…
Exploring diversity and biotechnological potential of lactic acid bacteria from tocosh - traditional Peruvian fermented potatoes - by high throughput…
2018
Lactic acid bacteria (LAB) diversity associated with tocosh, Peruvian traditional fermented potatoes, was for the first time investigated by culturing and high throughput sequencing (HTS) approaches. They were applied on three samples i.e. freshly harvested potatoes, one-month and eight-months production. While by culture-dependent approach a few Lactobacillus (Lb) species (Lb. sakei, Lb. casei, Lb. farciminis, Lb. brevis, Lb. fermentum) and Leuconostoc (Ln) mesenteroides were identified, twenty-four OTUs belonging to six LAB genera were considered in tocosh samples by HTS, being Lactobacillus dominant in all three samples. LAB predominated on fresh potatoes, while Clostridium, Zymophilus a…
Distribution, redox state and (bio)geochemical implications of arsenic in present day microbialites of Laguna Brava, Salar de Atacama
2018
Understanding how microorganisms adapted to the high arsenic concentration present on early Earth requires understanding of the processes involved in the arsenic biogeochemical cycle operating in living microbial mats. To this end, we investigated a living microbial mat from Laguna Brava (Salar de Atacama, Chile), a hypersaline lake with high arsenic concentration, using an array of conventional geochemical techniques, such as X-ray diffraction, SEM-EDX and Confocal Laser Scanning Microscopy (CLSM), combined with state-of-the-art high resolution scanning imaging techniques, including X-ray micro-fluorescence (μXRF) and X-ray Absorption Near Edge Structure (XANES) mapping. This experimental …
The NSL Chromatin-Modifying Complex Subunit KANSL2 Regulates Cancer Stem-like Properties in Glioblastoma That Contribute to Tumorigenesis.
2016
KANSL2 is an integral subunit of the nonspecific lethal (NSL) chromatin-modifying complex that contributes to epigenetic programs in embryonic stem cells. In this study, we report a role for KANSL2 in regulation of stemness in glioblastoma (GBM), which is characterized by heterogeneous tumor stem-like cells associated with therapy resistance and disease relapse. KANSL2 expression is upregulated in cancer cells, mainly at perivascular regions of tumors. RNAi-mediated silencing of KANSL2 in GBM cells impairs their tumorigenic capacity in mouse xenograft models. In clinical specimens, we found that expression levels of KANSL2 correlate with stemness markers in GBM stem-like cell populations. M…