Evaluation and monitoring of the water quality of an Argentinian urban river applying multivariate statistics.

In this work, we present the water quality assessment of an urban river, the San Luis River, located in San Luis Province, Argentina. The San Luis River flows through two developing cities; hence, urban anthropic activities affect its water quality. The river was sampled spatially and temporally, evaluating ten physicochemical variables on each water sample. These data were used to calculate a Simplified Index of Water Quality in order to estimate river water quality and infer possible contamination sources. Data were statistically analyzed with the opensource software R, 4.1.0 version. Principal component analysis, cluster analysis, correlation matrices, and heatmap analysis were performed. Results indicated that water quality decreases in areas where anthropogenic activities take place. Robust inferential statistical analysis was performed, employing an alternative of multivariate analysis of variance (MANOVA), MANOVA.wide function. The most statistically relevant physicochemical variables associated with water quality decrease were used to develop a multiple linear regression model to estimate organic matter, reducing the variables necessary for continuous monitoring of the river and, hence, reducing costs. Given the limited information available in the region about the characteristics and recovery of this specific river category, the model developed is of vital importance since it can quickly detect anthropic alterations and contribute to the environmental management of the rivers. This model was also used to estimate organic matter at sites located in other similar rivers, obtaining satisfactory results.

Testosterone is closely related to Leydig cell activity, environmental factors, and androgen receptor distribution in adult male lizards of Liolaemus cuyanus (Reptilia: Liolaemidae) during the reproductive cycle.

Testosterone, the primary sex hormone in male lizards, is closely linked to Leydig cell activity (the cells where steroidogenesis occurs) throughout the reproductive cycle, but testosterone action is related to androgen receptors (ARs) distribution in the seminiferous epithelium. In temperate zones, environmental factors detected through the hypothalamic-pituitary-gonadal axis, downregulate plasma testosterone, resulting in a seasonal reproductive cycle. The aim of this work is to study plasma testosterone in adult male lizards of Liolaemus cuyanus, an oviparous species, throughout its reproductive cycle and its relationship with Leydig cell histology, TotalLeydigCell/ActiveLeydigCell (TLC/ALC) ratio, environmental factors (temperature, relative humidity and solar irradiation) and ARs distribution in seminiferous epithelium. Specimens (N = 27) were captured (October to March) in a semi-arid zone (Valle de Matagusanos, San Juan, Argentina) and grouped into three relevant reproductive periods: pre-reproductive (PrR), reproductive (R), and post-reproductive (PsR). Significant differences in plasma testosterone were found among these periods, highest during R than in PsR. A significant positive correlation between plasma testosterone and TLC/ALC ratio was also observed. Plasma testosterone has a significant positive correlation only with solar irradiation, but not with the other variables. In PrR and R, ARs distribution was cytoplasmic and nuclear, shifting to only cytoplasmic in PsR. These results highlight the close correspondence between plasma testosterone, Leydig cell histology and activity, environmental factors, and ARs distribution, resulting in a synchronization that allows males of L. cuyanus to coordinate their reproductive cycle with the most favorable environmental conditions, probably for mating and birth of offspring.

Diuretic activity of Euphorbia serpens extracts in Wistar rats.

Euphorbia serpens has been used in central-west region of Argentina in traditional medicine as diuretic plant. The aim of this present study was to evaluate the diuretic activity of E. serpens in-vivo. We used dried aerial parts, and infusions from these were orally administered to Wistar rats. Its effect was evaluated using furosemide as a positive drug and isotonic salt solution as negative control. Their urine output was quantified at several time intervals. The volume of urine excreted and Na+ increased significantly, being similar to furosemide. Mannitol, was the main component in aqueous extracts of E. serpens, and the acetone extract showed the presence of Δ12- oleanane-type triterpenoids compounds, mainly hederagenin. No toxic effects were observed.

Evaluación preliminar de la callogénesis y organogénesis in vitro Leptochloa crinita (lag.) p. m. peterson & n. snow / Preliminary evaluation of in vitro callogenesis and organogenesis Leptochloa crinita (Lag.) P. M. Peterson & N. Snow

RESUMEN El cambio de uso de la tierra por diversos factores socio-económicos, climáticos, tecnológicos y culturales han tenido como consecuencia en la provincia de San Luis (Argentina) la pérdida de diversidad biológica, fragmentación y destrucción de hábitat, comprometiendo la existencia de la flora nativa, como es el caso de Leptochloa crinita (Lag.) P.M. Peterson & N. Snow, una especie con buena aptitud forrajera del monte chaqueño. Bajo este contexto, el presente trabajo tuvo como objetivo aplicar biotécnicas como alternativas para una propagación apropiada de este acervo genético. Se evaluó la organogénesis y callogénesis in vitro de diferentes explantos con distintos reguladores de crecimiento en un medio nutritivo Murashige y Skoog. El tratamiento con 6 mg l-1 de 2,4-D estimuló la callogénesis, mientras que los tratamientos combinados de auxinas y citocininas presentaron las mayores tasas de morfogénesis. El desarrollo de esta biotécnica permite disponer de metodologías adecuadas para iniciar ensayos de conservación in vitro, análisis de la variabilidad genética e inicio de programas de domesticación y mejoramiento genético.

ABSTRACT In San Luis (Argentina), land-use change due to a variety of socioeconomic, climatic, technological and cultural factors has caused the loss of biological diversity, fragmentation and habitat destruction, compromising the existence of native flora, such as in the case of Leptochloa crinita (Lag.) PM Peterson & N. Snow, a species with good forage aptitude from the Chaco forest. In this context, the present work aimed to apply biotechniques as an alternative for an appropriate propagation of this gene pool. In vitro organogenesis and callogenesis of several explants were evaluated with different growth regulators on a Murashige and Skoog nutrient medium. Treatment with 6 mg l-1 of 2,4-D stimulated callogenesis, while combined auxin and cytokinin treatments presented the highest rates of morphogenesis. The development of this biotechnique makes it possible to have adequate methodologies to initiate in vitro conservation trials, analysis of genetic variability and the initiation of domestication and breeding programs.

Effect of Arbuscular Mycorrhizal Colonization on Cadmium-Mediated Oxidative Stress in Glycine max (L.) Merr.

Cadmium is a heavy metal (HM) that inhibits plant growth and leads to death, causing great losses in yields, especially in Cd hyperaccumulator crops such as Glycine max (L.) Merr. (soybean), a worldwide economically important legume. Furthermore, Cd incorporation into the food chain is a health hazard. Oxidative stress (OS) is a plant response to abiotic and biotic stresses with an intracellular burst of reactive oxygen species (ROS) that causes damage to lipids, proteins, and DNA. The arbuscular mycorrhizal fungal (AMF) association is a plant strategy to cope with HM and to alleviate OS. Our aim was to evaluate the mitigation effects of mycorrhization with AMF Rhizophagus intraradices on soybean growth, nutrients, Cd accumulation, lipid peroxidation, and the activity of different antioxidant agents under Cd (0.7-1.2 mg kg-1 bioavailable Cd) induced OS. Our results suggest that glutathione may act as a signal molecule in a defense response to Cd-induced OS, and mycorrhization may avoid Cd-induced growth inhibition and reduce Cd accumulation in roots. It is discussed that R. intraradices mycorrhization would act as a signal, promoting the generation of a soybean cross tolerance response to Cd pollution, therefore evidencing the potential of this AMF association for bioremediation and encouragement of crop development, particularly because it is an interaction between a worldwide cultivated Cd hyperaccumulator plant and an AMF-HM-accumulator commonly present in soils.