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Decreased forkhead box O1 (FoxO1) activity induces hyperlipidemia and increased PPARγ, leading to hyperlipidemia in association with endoplasmic reticulum (ER) stress. In the liver, aging and comorbidities such as hyperlipidemia and diabetes significantly influence a wide variety of steatosis, but the underlying mechanisms are complex and remain elusive.
To establish the modulatory role of FoxO1 and the functional consequences of its altered interaction with PPARγ in the present study, we utilized a cell culture system, aged rats and diabetic db/db mice.
We found that, under ER stress, FoxO1 induces PPARγ-mediated lipid accumulation in aged rat livers. Our data showed that the FoxO1-induced hepatic lipid accumulation was negatively regulated by Akt signaling. PPARγ, a key lipogenesis transcription factor, was increased in aged liver, resulting in lipid accumulation via hepatic ER stress under hyperglycemic conditions. We further demonstrated that loss of FoxO1 causes a decline in PPARγ expression and reduces lipid accumulation. In addition, the interaction between FoxO1 and PPARγ was shown to induce hepatic steatosis in aging and db/db mice.
We provide evidence that, in aged rats, FoxO1 interaction with PPARγ promotes hepatic steatosis, due to hyperglycemia-induced ER stress, which causes an impairment in Akt signaling, such in aging-related diabetes.
1. Much is known about the brief adult phase of fireflies. However, fireflies spend a relatively long developmental period under the soil surface. Climatic and soil conditions may directly affect the eggs, larvae and pupae and indirectly affect them through predators, competitors and prey items. Climatic conditions during the early life stages of this iconic species are therefore relevant to their hypothesized decline within the context of global warming.2. We extracted data on the abundance of fireflies from the publicly available citizen data set across North America over a period of nine years. We document the effects of weather in the 24 months prior to the observations of firefly abundance based on 6761 observations. 3. Climatic conditions during both the larval and adult phases have a non-linear effect on adult firefly abundance. Maximum winter and spring temperatures and mean precipitation in the 20month period prior to the observations had the greatest impact on the abundance of firefly adults.Low maximum soil moisture during the 5-19 months preceding the observations affected the adult abundance negatively, and high maximum soil moisture positively. 4. After correcting the firefly abundance for these weather effects, we estimate that the abundance of fireflies increased over the time period of this study.5. Our study suggests that early life climatic conditions have a small but significant impact on adult firefly abundance with a total R 2 of 0.017.
Organisms are exposed to electromagnetic fields from the introduction of wireless networks that send information all over the world. In this study we examined the impact of exposure to the fields from mobile phone base stations (GSM 900 MHz) on the reproductive capacity of small, virgin, invertebrates. A field experiment was performed exposing four different invertebrate species at different distances from a radiofrequency electromagnetic fields (RF EMF) transmitter for a 48-h period. The control groups were isolated from EMF exposure by use of Faraday cages. The response variables as measured in the laboratory were fecundity and number of offspring. Results showed that distance was not an adequate proxy to explain dose-response regressions. No significant impact of the exposure matrices, measures of central tendency and temporal variability of EMF, on reproductive endpoints was found. Finding no impact on reproductive capacity does not fully exclude the existence of EMF impact, since mechanistically models hypothesizing non-thermal-induced biological effects from RF exposure are still to be developed. The exposure to RF EMF is ubiquitous and is still increasing rapidly over large areas. We plea for more attention toward the possible impacts of EMF on biodiversity.
Abstract:Birds are an important part of the agricultural landscape, as having nature value, but also as pest control agents and bio-indicators for the health of the environment. Here we look at linear non-crop elements in agricultural areas as a potential source of food for nestlings of avian species. We measured invertebrate availability as it relates to structural complexity at the local and landscape levels in three counties in central Illinois. Invertebrates were measured with taxonomic diversity, abundance, and estimated biomass during spring of 2012 and 2013. Our study shows that easily modifiable field edge characteristics have the greatest impact on invertebrate diversity and abundance, as compared to field and landscape features. This finding shows that a potential invertebrate food source as measured by both diversity and biomass, may be easily enhanced without changes to agricultural practices.
In the American Midwest, summer fires are infrequent, and there is little information on their impact on ecosystems. After an accidental wildfire in a 20 ha grassland restoration, new growth provided effective substrate for the noctuid species corn earworm, Helicoverpa zea (Boddie), and tobacco budworm, Heliothis virescens (Fabricius). These agricultural pests feed on a number of important crop species and have been implicated in crop losses of up to 50 %. Invertebrate collections were made at 16 days, 45 days, 70 days, and 101 days post fire. A comparison of burned and unburned areas at 70 days post fire show 18 times the number of Lepidoptera larvae collected in pitfall traps in the burned area compared to the adjacent unburned area of the grasslands. These findings demonstrate that a mid-summer fire can affect the abundance of economically important insects.
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