3 research outputs found
An analysis of the effects of various compounds on alcohol and high-fat-diet-induced steatosis in rats and mice:
No full textExcessive alcohol consumption is known to result in fatty liver, or steatosis. A high-fat, low-carbohydrate diet also results in fatty liver. Furthermore, fatty liver is known to precede cirrhosis in both animals and humans, and cirrhosis precedes primary hepatocellular carcinoma in humans. A series of studies was first undertaken to determine whether exercise and/or certain dietary manipulations could affect fatty liver. Long-Evans rats were given either a high-fat, low-carbohydrate or a high-carbohydrate, low-fat version of liquid diet with or without alcohol. Livers were analyzed for fat and measures of carbohydrate metabolism in liver and plasma were taken, as well as blood glucose alcohol concentrations. Next, added exercise (run wheel), caffeine, antioxidants such as Vitamin E, diphenyl-para-phenylene diamine (DPPD), and selenium were examined as were the dietary additives cranberry powder and soy protein. Finally, based on ambiguous results involving each agent separately, caffeine and DPPD were combined. Following the conclusion of rat studies, C57BL6 mice were given a modified version of the Leiber-deCarli liquid diet with alcohol. The calorie manipulation described above was repeated in mice to determine whether alcohol-induced fatty liver would be exacerbated in the presence of a high-fat diet. Subsequently, the dietary additives Vitamin E, DPPD and Trolox were added. Striatum was taken for HPLC, and livers were taken for liver fat analysis and malondialdehyde (MDA) assay (as a measure of oxidative stress) respectively. Finally, an experiment was undertaken to determine a time course for withdrawal seizures in mice.
In rats, differences in liver glycogen did not account for differences in liver fat. Exercise and caffeine both resulted in significant changes in weight gain, and while combined they appeared to reduce alcohol-induced fatty liver, the effect was not significant. Separately, no protective properties of either exercise or caffeine were observed. Vitamin E and selenium were found to exacerbate alcohol-induced fatty liver, while DPPD did not. Neither cranberry powder nor soy protein affected alcohol-induced fatty liver. DPPD combined with caffeine reduced alcohol-induced fatty liver significantly (p<0.05).
Adult mice were able to tolerate 4.5% ethanol in a high-fat liquid diet. The high-fat diet resulted in liver fat values significantly higher than high-carbohydrate when combined with alcohol. Vitamin E appeared to exacerbate fatty liver in mice, but differences were not significant. There were significant differences in oxidative stress; Vitamin E and Trolox reduced MDA significantly over diet plus alcohol alone. All animals experienced withdrawal seizures between 3 and 5 hours after removal of alcohol. There were significant differences in serotonin turnover (5HIAA/5HT) in animals fed a high-fat diet without alcohol vs. chow controls.Ph.D.Includes bibliographical references (p. 52-60)by Bonnie Nola
Author Correction: One sixth of Amazonian tree diversity is dependent on river floodplains
No full textCorrection to: Nature Ecology & Evolution https://doi.org/10.1038/s41559-024-02364-1, published online 11 March 2024.
In the version of the article initially published, the affiliation of Edgardo Manuel Latrubesse was incorrect and has now been amended to Environmental Sciences Graduate Program-CIAMB, Federal University of Goiás, Goiânia, Brazil in the HTML and PDF versions of the article
One sixth of Amazonian tree diversity is dependent on river floodplains
No full textAmazonia’s floodplain system is the largest and most biodiverse on Earth. Although forests are crucial to the ecological integrity of floodplains, our understanding of their species composition and how this may differ from surrounding forest types is still far too limited, particularly as changing inundation regimes begin to reshape floodplain tree communities and the critical ecosystem functions they underpin. Here we address this gap by taking a spatially explicit look at Amazonia-wide patterns of tree-species turnover and ecological specialization of the region’s floodplain forests. We show that the majority of Amazonian tree species can inhabit floodplains, and about a sixth of Amazonian tree diversity is ecologically specialized on floodplains. The degree of specialization in floodplain communities is driven by regional flood patterns, with the most compositionally differentiated floodplain forests located centrally within the fluvial network and contingent on the most extraordinary flood magnitudes regionally. Our results provide a spatially explicit view of ecological specialization of floodplain forest communities and expose the need for whole-basin hydrological integrity to protect the Amazon’s tree diversity and its function
