428 research outputs found
Gas Exchange Relations of Ungrafted Grapevines (cv. Carménère) Growing Under Irrigated Field Conditions
A study was carried out to evaluate the leaf gas exchange relations and water-use efficiency (WUE) of ungrafted Carménère (Vitis vinifera L.) grapevines growing under field conditions and different levels of water stress. Stomatal conductance (gs), transpiration (E), net CO2 assimilation (AN) and stem water potential (Ψs) were measured at midday in a drip-irrigated commercial vineyard located in the Maule Valley (Chile) during three growing seasons (2005 to 2009). In addition, the instantaneous (AN/E) and intrinsic (AN/gs) water-use efficiencies and stomatal sensitivity factor (k) were estimated for the own-rooted grapevines. In this study a significant non-linear relationship was observed between AN and gs (r2 = 0.82), with values of AN decreasing from 14.9 to 3.5 μmol/m2/sec as gs diminished from 0.5 to 0.05 mol/m2/sec. This resulted in a progressive increase in WUEi (intrinsic water use efficiency). A significant linear relationship was observed between Ψs and gs (r2 = 0.39) for measurements taken before and after véraison, with an increasing scattering from -1.6 to -0.4 MPa. Finally, k decreased as water stress increased, with values of 234 and 120 for no and severe water stress respectively, while k ranged from 264 to 480 and 255 to 297 for the measurements taken before and after véraison respectively. Based on the results obtained in the present study, the cultivar Carménère could be classified as drought tolerant at low water potentials, with a large range of physiological parameters changing in response to water stress
Evaluación de la Huella Hídrica del Lirio Japonés (Hemerocallis)
Colombia es uno de los países que se caracteriza por su gran riqueza en biodiversidad y fuentes hídricas; así mismo es uno de los 10 países con mayor disponibilidad de este recurso en el mundo. Los seres humanos consumen agua diariamente en todo lo que realizan (bienes, productos, servicios). Es así, como la huella hídrica se utiliza como un indicador del consumo directo o indirecto del agua, tanto en el ámbito doméstico como en el industrial. Esta permite determinar el volumen total de agua dulce que se emplea para la elaboración de bienes, en servicios consumidos por los individuos o en una actividad en particular. El objetivo de esta investigación se centró en evaluar la huella hídrica para la producción de flores de Lirio Japonés (Hemerocallis) en un predio del municipio de Rondon – Boyacá (Colombia). La propuesta metodológica planteada por los autores para este estudio consta de tres fases: el diagnostico, el modelamiento y el análisis de resultados. El resultado obtenido para la huella hídrica azul es 1.76×10-4L/tallo, para la huella verde es 1×10-8l/tallo y para la huella gris es 2.06x10-4L/ tallo. Finalmente, una huella hídrica total es de 3,82×10-4L/tallo. En conclusión, la huella hídrica total del cultivo de Lirio Japonés (7.64x10-3m3/ton) en comparación con la huella hídrica por producción de flores (900m3/ton), aporta tan solo el 0.00085% del total, por lo cual se puede afirmar que este cultivo es uno de los que tiene un menor aporte en dicha huella total para la producción de flores en Colombia
Adipogenesis Regulation and Endocrine Disruptors: Emerging Insights in Obesity
Indexación: Scopus.Endocrine disruptors (EDs) are defined as environmental pollutants capable of interfering with the functioning of the hormonal system. They are environmentally distributed as synthetic fertilizers, electronic waste, and several food additives that are part of the food chain. They can be considered as obesogenic compounds since they have the capacity to influence cellular events related to adipose tissue, altering lipid metabolism and adipogenesis processes. This review will present the latest scientific evidence of different EDs such as persistent organic pollutants (POPs), heavy metals, "nonpersistent" phenolic compounds, triclosan, polybrominated diphenyl ethers (PBDEs), and smoke-derived compounds (benzo -alpha-pyrene) and their influence on the differentiation processes towards adipocytes in both in vitro and in vivo models.https://www.hindawi.com/journals/bmri/2020/7453786/#copyrigh
Variation in the Composition and In Vitro Proinflammatory Effect of Urban Particulate Matter from Different Sites
Spatial variation in particulate matter–related health and toxicological outcomes is partly due to its composition. We studied spatial variability in particle composition and induced cellular responses in Mexico City to complement an ongoing epidemiologic study. We measured elements, endotoxins, and polycyclic aromatic hydrocarbons in two particle size fractions collected in five sites. We compared the in vitro proinflammatory response of J774A.1 and THP‐1 cells after exposure to particles, measuring subsequent TNFα and IL‐6 secretion. Particle composition varied by site and size. Particle constituents were subjected to principal component analysis, identifying three components: C 1 (Si, Sr, Mg, Ca, Al, Fe, Mn, endotoxin), C 2 (polycyclic aromatic hydrocarbons), and C 3 (Zn, S, Sb, Ni, Cu, Pb). Induced TNFα levels were higher and more heterogeneous than IL‐6 levels. Cytokines produced by both cell lines only correlated with C 1 , suggesting that constituents associated with soil induced the inflammatory response and explain observed spatial differences. © 2013 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:87‐97, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/jbt.21471Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96321/1/jbt21471.pd
Developmental Reaction Norms for Water Stressed Seedlings of Succulent Cacti
Succulent cacti are remarkable plants with capabilities to withstand long periods of drought. However, their adult success is contingent on the early seedling stages, when plants are highly susceptible to the environment. To better understand their early coping strategies in a challenging environment, two developmental aspects (anatomy and morphology) in Polaskia chichipe and Echinocactus platyacanthus were studied in the context of developmental reaction norms under drought conditions. The morphology was evaluated using landmark based morphometrics and Principal Component Analysis, which gave three main trends of the variation in each species. The anatomy was quantified as number and area of xylem vessels. The quantitative relationship between morphology and anatomy in early stages of development, as a response to drought was revealed in these two species. Qualitatively, collapsible cells and collapsible parenchyma tissue were observed in seedlings of both species, more often in those subjected to water stress. These tissues were located inside the epidermis, resembling a web of collapsible-cell groups surrounding turgid cells, vascular bundles, and spanned across the pith. Occasionally the groups formed a continuum stretching from the epidermis towards the vasculature. Integrating the morphology and the anatomy in a developmental context as a response to environmental conditions provides a better understanding of the organism's dynamics, adaptation, and plasticity
Mycobacterium tuberculosis ecology in Venezuela: epidemiologic correlates of common spoligotypes and a large clonal cluster defined by MIRU-VNTR-24
<p>Abstract</p> <p>Background</p> <p>Tuberculosis remains an endemic public health problem, but the ecology of the TB strains prevalent, and their transmission, can vary by country and by region. We sought to investigate the prevalence of <it>Mycobacterium tuberculosis </it>strains in different regions of Venezuela. A previous study identified the most prevalent strains in Venezuela but did not show geographical distribution nor identify clonal genotypes. To better understand local strain ecology, we used spoligotyping to analyze 1298 <it>M. tuberculosis </it>strains isolated in Venezuela from 1997 to 2006, predominantly from two large urban centers and two geographically distinct indigenous areas, and then studied a subgroup with MIRU-VNTR 24 loci.</p> <p>Results</p> <p>The distribution of spoligotype families is similar to that previously reported for Venezuela and other South American countries: LAM 53%, T 10%, Haarlem 5%, S 1.9%, X 1.2%, Beijing 0.4%, and EAI 0.2%. The six most common shared types (SIT's 17, 93, 605, 42, 53, 20) accounted for 49% of the isolates and were the most common in almost all regions, but only a minority were clustered by MIRU-VNTR 24. One exception was the third most frequent overall, SIT 605, which is the most common spoligotype in the state of Carabobo but infrequent in other regions. MIRU-VNTR homogeneity suggests it is a clonal group of strains and was named the "Carabobo" genotype. Epidemiologic comparisons showed that patients with SIT 17 were younger and more likely to have had specimens positive for Acid Fast Bacilli on microscopy, and patients with SIT 53 were older and more commonly smear negative. Female TB patients tended to be younger than male patients. Patients from the high incidence, indigenous population in Delta Amacuro state were younger and had a nearly equal male:female distribution.</p> <p>Conclusion</p> <p>Six SIT's cause nearly half of the cases of tuberculosis in Venezuela and dominate in nearly all regions. Strains with SIT 17, the most common pattern overall may be more actively transmitted and SIT 53 strains may be less virulent and associated with reactivation of past infections in older patients. In contrast to other common spoligotypes, strains with SIT 605 form a clonal group centered in the state of Carabobo.</p
- …