Physiological traits as affected by heat stress in sheep—A review

Recent results continue to show the general consensus that ozone-related increases in UV-B radiation can negatively influence many aquatic species and aquatic ecosystems (e.g., lakes, rivers, marshes, oceans). Solar UV radiation penetrates to ecological significant depths in aquatic systems and can affect both marine and freshwater systems from major biomass producers (phytoplankton) to consumers (e.g., zooplankton, fish, etc.) higher in the food web. Many factors influence the depth of penetration of radiation into natural waters including dissolved organic compounds whose concentration and chemical composition are likely to be influenced by future climate and UV radiation variability. There is also considerable evidence that aquatic species utilize many mechanisms for photoprotection against excessive radiation. Often, these protective mechanisms pose conflicting selection pressures on species making UV radiation an additional stressor on the organism. It is at the ecosystem level where assessments of anthropogenic climate change and UV-related effects are interrelated and where much recent research has been directed. Several studies suggest that the influence of UV-B at the ecosystem level may be more pronounced on community and trophic level structure, and hence on subsequent biogeochemical cycles, than on biomass levels per se.

/pdf/effects-of-solar-uv-radiation-on-aquatic-ecosystems-and-njcrblgzlq.pdf

Effects of solar UV radiation on aquatic ecosystems and interactions with climate change

Brown adipocytes are thermogenic cells which play an important role in energy balance. Their thermogenic activity is due to the presence of a mitochondrial uncoupling protein (UCP). Until recently, it was admitted that in rodents brown adipocytes were mainly located in classical brown adipose tissue (BAT). In the present study, we have investigated the presence of UCP protein or mRNA in white adipose tissue (WAT) of rats. Using polymerase chain reaction or Northern blot hybridization, UCP mRNA was detected in mesenteric, epidydimal, retroperitoneal, inguinal and particularly in periovarian adipose depots. The uncoupling protein was detected by Western blotting in mitochondria from periovarian adipose tissue. When rats were submitted to cold or to treatment with a beta-adrenoceptor agonist, UCP expression was increased in this tissue as in typical brown fat. Moreover, the expression was decreased in obese fa/fa rats compared to lean controls. Morphological studies showed that periovarian adipose tissue of rats kept at 24 degrees C contained cells with numerous typical BAT mitochondria with or without multilocular lipid droplets. Immunocytochemistry confirmed that multilocular cells expressed mitochondrial UCP. Furthermore, the number of brown adipocytes and the density of mitochondrial cristae increased in parallel with exposure to cold. These results demonstrate that adipocytes expressing UCP are present in adipose deposits considered as white fat. They suggest the existence of a continuum in rodents between BAT and WAT, and a great plasticity between adipose tissue phenotypes. The physiological importance of brown adipocytes in WAT and the regulation of UCP expression remain open questions.

Occurrence of brown adipocytes in rat white adipose tissue: molecular and morphological characterization.

Amphibians and agricultural chemicals: Review of the risks in a complex environment

Epidemiological evidence links an individual's susceptibility to chronic disease in adult life to events during their intrauterine phase of development. Biologically this should not be unexpected, ...

Placental Origins of Chronic Disease.

Growth, metabolic rate, and energy reserves of Cherax quadricarinatus (von Martens, 1868) juveniles were evaluated in crayfish acclimated for 16 weeks to either 25°C (temperature near optimum) or 20°C (marginal for the species). Additionally, the modulating effect of ecdsyone on acclimation was studied. After 12 weeks of exposure, weight gain of both experimental groups acclimated to 25°C (control: C25, and ecdysone treated: E25) was significantly higher than that of those groups acclimated to 20°C (C20 and E20). A total compensation in metabolic rate was seen after acclimation from 25°C to 20°C; for both the control group and the group treated with ecdysone. A Q 10 value significantly higher was only observed in the group acclimated to 20°C and treated with ecdysone. A reduction of glycogen reserves in both hepatopancreas and muscle, as well as a lower protein content in muscle, was seen in both groups acclimated to 20°C. Correspondingly, glycemia was always higher in these groups. Increased lipid levels were seen in the hepatopancreas of animals acclimated to 20°C, while a higher lipid level was also observed in muscle at 20°C, but only in ecdysone-treated crayfish.

/pdf/effects-of-both-ecdysone-and-the-acclimation-to-low-4kn50u5v0t.pdf

Effects of both ecdysone and the acclimation to low temperature on growth and metabolic rate of juvenile freshwater crayfish Cherax quadricarinatus (Decapoda, Parastacidae)

Itzick Vatnick

Papers

Effects of both ecdysone and the acclimation to low temperature on growth and metabolic rate of juvenile freshwater crayfish Cherax quadricarinatus (Decapoda, Parastacidae)

Effects of Acid Exposure on Natural Resistance and Mortality of Adult