Effect of Omega-3 Rich High-Fat Diet on Markers of Tissue Lipid Metabolism in Glucocorticoid-Treated Mice.

Glucocorticoids (GCs) are some of the most widely prescribed therapies for treating numerous inflammatory diseases and multiple cancer types. With chronic use, GCs' therapeutic benefits are concurrent with deleterious metabolic side effects, which worsen when combined with a high-fat diet (HFD). One characteristic of the common Western HFD is the presence of high omega-6 polyunsaturated fatty acids (PUFAs) and a deficiency in omega-3 PUFAs. The aim of this experiment was to determine whether fat composition resulting from HFD affects glucocorticoid-induced alterations in lipid-handling by the liver and skeletal muscle. Male wild-type C57BL/6 mice were randomized into two groups: n-6 (45% fat 177.5 g lard) and n-3 (45% fat 177.5 g Menhaden oil). After 4 weeks on their diets, groups were divided to receive either daily injections of dexamethasone (3 mg/kg/day) or sterile PBS for 1 week while continuing diets. The n-3 HFD diet attenuated adipose and hepatic fatty accumulation and prevented GC-induced increases in liver lipid metabolism markers Cd36 and Fabp. N-3 HFD had little effect on markers of lipid metabolism in oxidative and glycolytic skeletal muscle and was unable to attenuate GC-induced gene expression in the muscle. The present study's result demonstrated that the change of fat composition in HFD could beneficially alter the fatty acid accumulation and associated lipid metabolism markers in mice treated with dexamethasone.

The highly crystalline PET found in plastic water bottles does not support the growth of the PETase-producing bacterium Ideonella sakaiensis.

Ideonella sakaiensis produces an enzyme, PETase, that is capable of hydrolyzing polyethylene terephthalate (PET) plastic. We demonstrate that although I. sakaiensis can grow on amorphous plastic, it does not grow on highly crystalline plastic under otherwise identical conditions. Both amorphous film and amorphous plastic obtained from commercial food containers support the growth of the bacteria, whereas highly crystalline film and the highly crystalline body of a plastic water bottle do not support growth. Highly crystalline PET can be melted and rapidly cooled to make amorphous plastic which then supports bacterial growth, whereas the same plastic can be melted and slowly cooled to make crystalline plastic which does not support growth. We further subject a plastic water bottle to a top-to-bottom analysis, finding that only amorphous sections are degraded, namely the finish (threading), the topmost portion of the shoulder which connects to the finish, and the area immediately surrounding the centre of the base. Finally, we use these results to estimate that the percentage of non-degradable plastic in plastic water bottles ranges from 52% to 82% (depending on size), demonstrating that most of the plastic found in PET water bottles will not be degraded by I. sakaiensis.