Many amphibian species are vulnerable to environmental changes, especially in the tropics where presumably a large number of species have evolved narrow niches. Rapid environmental changes, such as deforestation, may promote stress responses in anurans that could affect population viability. The stress response in vertebrates is highly conserved, often involving the liberation of glucocorticoids hormones and the recruitment of immune competent cells. The objective of this work was to evaluate leukocyte profiles among individuals of two neotropical anuran species affected by anthropogenic habitat alteration. We took blood samples from adult individuals of Physalaemus cuvieri and Scinax x-signatus in natural and converted habitats in NE Brazil. We analyzed differential leukocyte counts, where increases in neutrophils and decreases in lymphocytes are indicative of a stress response. Specimens of S. x-signatus captured in highly altered habitats presented a higher neutrophil:lymphocyte (N: L) ratios than individuals from natural habitats. In contrast, P. cuvieri individuals exhibited no difference in N:L ratios between habitat types. These results suggest that the immune response depends on the species and the level of habitat alteration. Although S. x-signatus can be considered a generalist species, individuals from this species exhibited increased stress response associated with habitat alteration. The lack of a strong stress response of P. cuvieri, may suggest that this species is more tolerant of habitat alteration or that those individuals have acclimated to anthropogenic stressors more rapidly than S. x-signatus. These variable responses of immune function in highly altered habitats suggest avenues for future experimental work that examines responses to multiple stressors, including disease, which could scale to population trends in altered habitats.
Glucocorticoids and melatonin (MEL) show integrated and complex immunomodulatory effects, mostly described for endotherms, yet underexplored in amphibians. In this context, the RT-qPCR of molecules mediating inflammatory processes in amphibians is a valuable tool to explore the relationships among molecular biology, endocrine mediators, and immune response in these animals. In this study, toads (Rhinella diptycha) received an intraperitoneal saline injection or lipopolysaccharide (LPS; 2 mg/kg). Six hours post-injection, we analyzed plasma corticosterone (CORT) and MEL levels and pro and anti-inflammatory molecules (IL-1β, IL-6, IL-10, IFN-γ, and C1s). We found increased CORT and decreased MEL levels in response to LPS. Also, IL-1β, IL-6, and IL-10 were upregulated in LPS-injected toads compared with saline-injected. Overall, our results demonstrate an LPS-induced inflammatory response with endocrine and immune modulation in R. diptycha toads, exhibiting expected patterns for an inflammatory stimulus within this timeframe (6 h post-injection). Toads were responsive to LPS by secreting different cytokines, such as proinflammatory cytokines IL-1β and IL-6, related to immune cell attraction to inflammatory sites and the anti-inflammatory cytokine IL-10, which limits the rate of leukocyte infiltration, inflammation, and downregulates the expression of proinflammatory cytokines. Increased circulating CORT levels are probably associated with the activation of the hypothalamus-pituitary-interrenal axis by the LPS and the endocrine actions of IL-6. Furthermore, decreased circulating MEL levels are likely due to inhibited MEL secretion by the pineal gland by inflammatory stimuli, indicating the activation/existence of the immune-pineal axis in amphibians.
Identificar situações com as quais a comunidade acadêmica se defronta quanto à geração de resíduos é imprescindível para que haja uma elaboração de programas e políticas de gestão sustentável em universidades. Este trabalho visou compreender como se dá a sensibilização da comunidade acadêmica da Cidade Universitária/ UFMA, acerca da produção de resíduos sólidos e seus devidos impactos ambientais. A metodologia baseou-se na aplicação de 509 questionários, com perguntas acerca de políticas de reciclagem e coleta seletiva, abrangendo 33 cursos de graduação e pós-graduação de diversas áreas e seis instâncias administrativas. De acordo com os resultados, 67,97% dos entrevistados conhecem as políticas de reaproveitamento, reutilização e reciclagem de resíduos e 92,32% afirmou que participaria de um programa interno caso houvesse incentivo para tal. Assim, é importante ressaltar que ainda que incentivado pelas instâncias administrativas, uma campanha efetiva deve incluir a sensibilização dos integrantes da comunidade acadêmica em questão.
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