Ant Species Richness Variation Mediated by Seasonality in Two Ant-Acacias from Oaxaca, Mexico

Climatic conditions affect the richness of ants resulting in number variation throughout the year. The ants present in the Neotropical system Acacia-Pseudomyrmex have been previously studied considering only one sampling season. In contrast, in this study we analyze the richness in two ant-acacia systems during the rainy and dry seasons. The study was carried out on a plot located in the state of Oaxaca, Mexico where 14 ant species, 3 mutualistic and 11 non-mutualistic were found, of which 2 represent new records for the state. Ant species number differed between ant-acacia species and between seasons. The highest richness was recorded in Acacia hindsii in both rainy and dry seasons, corresponding with a low-reward host. During the dry season, A. hindsii represents a highly valuable resource. This study shows that the neotropical system is much more dynamic than it has been previously considered and offers a valuable opportunity for subsequent ecological studies for a better understanding of this complex system.

Role of Angiotensin-(1-7) on Renal Hypertrophy in Streptozotocin-Induced Diabetes Mellitus

Participation of angiotensin II in chronic kidney diseases including diabetic nephropathy (DN) has been extensively described. Similarly, several studies support a protective role for angiotensin-(1-7). However, other studies suggest that some of the cellular effects of angiotensin-(1-7) may be deleterious. The objective of this study was to determine the role of exogenous angiotensin-(1-7) on renal hypertrophy development in rats with streptozotocin-induced diabetes. A control group and three groups of rats with streptozotocin-induced diabetes: untreated diabetic rats, diabetic rats treated with captopril, and diabetic rats treated with angiotensin-(1-7), were studied. After two weeks of treatment, the kidneys were removed under anesthesia with pentobarbital. The kidneys were weighed and the renal cortex was separated for analysis of AT1R, TGF-β1, MASR, and ACE2 expression by western blot. Rats in the three groups with diabetes had hyperglycemia, increased food and water consumption, and higher urinary volume than control rats. Treatment with captopril or angiotensin-(1-7) reversed streptozotocin-induced renal hypertrophy, measured by kidney weight, protein/DNA ratio in renal cortex, glomerular area, or proximal tubular cells area, proteinuria, and creatinine clearance reduction. AT1R, TGF-β1, and MAS receptor expression in renal cortex of diabetic rats increased significantly as compared to controls (p

New Reports of Spiders in Three Mexican Ant-Acacias

The richness of spider species on the foliage of Mexican ant-acacias in Los Tuxtlas (Veracruz), and Santiago Pinotepa Nacional (Oaxaca) was documented. A total of 11 species, grouped into five families were found;in Los Tuxtlas five species representing two families were identified, whereas in Santiago Pinotepa Nacional, the number of taxa was eight, belonging to five families. The richness of spiders in Santiago Pinotepa Nacional was higher than that found in Los Tuxtlas. In both locations Nephila clavipes Linnaeus and Eustala illicita O. Pickard-Cambridge, both from Araneidae, were found;these species had been previously reported as common inhabitants of Central American ant-acacias. The presence of E. illicita in Mexican myrmecophytic acacias was confirmed. A total of 10 species grouped into five families are reported for the first time inhabiting Mexican ant-acacias, increasing the richness of spider interactions documented in Mexico. This study showed that the occurrence of spiders in the Vachellia-Pseudomyrmex mutualism system has been overlooked and is likely more common than what has been reported until now. This opens an opportunity for the study of the evolution of spider-ant-plant interactions.