Search

This study examines the relationship between the algal biomass as well as lipid and triglyceride contents in Isochrysis galbana and variation in nutrient culture conditions such as phosphorus concentration and iron concentration. From the selected experiments, a clear algal growth drop expressed by number of cells, optical density and dried weight, as well strongly participated in the lipid and triglyceride cumulation, which show a positive significant effect on lipid productivity and triglyceride productivity. In the first experiment of this study, the phosphorus concentration in the medium was reduced to 75%, 50%, and 25% and complete absence (0%) of the original concentration in Walne's medium, whereas the iron concentration was kept constant in the medium. The next experiment, the optimum phosphorus concentration (25%) granting high lipid product was tested with different concentrations of iron from 100 to 0% with five concentrations. Though, the algal growth nonsignificant affected, abundant increases in lipids and triglyceride contents (49.5% and 14.7% of dry weight respectively) was noticed at the concentration of phosphorus of culture medium was decreased to (25%). However, hyperaccumulations of lipid and triglyceride (60.3% and 18.4% on the basis of dry weight, respectively) were acquired by the incorporation of 25% phosphorus and 25% iron. The simple regression analysis suggested the combination effect of phosphorus limitation and iron deprivation on lipid and triglyceride cumulation, and it was not as substantial as to phosphorus starvation tension.

Background and Aims: Metabolic factors initiating adipose tissue expansion and ectopic triglyceride accumulation are not completely understood. We aimed to investigate the independent role of circulating glucose, NEFA and insulin on glucose and NEFA uptake, and lipogenesis in skeletal muscle and subcutaneous adipose tissue (SCAT)., Methods and Results: Twenty-two pigs were stratified according to four protocols: 1) and 2) low NEFA + high insulin ± high glucose (hyperinsulinaemia-hyperglycaemia or hyperinsulinaemia-euglycaemia), 3) high NEFA + low insulin (fasting), 4) low NEFA + low insulin (nicotinic acid). Positron emission tomography with [ 18 F]fluoro-2-deoxyglucose and [ 11 C]acetate, was combined with [ 14 C]acetate and [U- 13 C]palmitate enrichment techniques to assess glucose and lipid metabolism. Hyperinsulinaemia increased glucose extraction, whilst hyperglycaemia enhanced glucose uptake in skeletal muscle and SCAT. In SCAT, during hyperglycaemia, elevated glucose uptake was accompanied by greater [U- 13 C]palmitate-TG enrichment compared to the other groups, and by a 39% increase in de novo lipogenesis (DNL) compared to baseline, consistent with a 70% increment in plasma lipogenic index. Conversely, in skeletal muscle, [U- 13 C]palmitate-TG enrichment was higher after prolonged fasting., Conclusions: Our data show the necessary role of hyperglycaemia-hyperinsulinaemia vs euglycaemia-hyperinsulinaemia in promoting expansion of TG stores in SCAT, by the consensual elevation in plasma NEFA and glucose uptake and DNL. In contrast, skeletal muscle NEFA uptake for TG synthesis is primarily driven by circulating NEFA levels. These results suggest that a) prolonged fasting or dietary regimens enhancing lipolysis might promote muscle steatosis, and b) the control of glucose levels, in association with adequate energy balance, might contribute to weight loss., (Copyright © 2017 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.)

Objective: Brown adipose tissue (BAT) is compositionally distinct from white adipose tissue (WAT) in terms of triglyceride and water content. In adult humans, the most significant BAT depot is localized in the supraclavicular area. Our aim is to differentiate brown adipose tissue from white adipose tissue using fat T2* relaxation time mapping and signal-fat-fraction (SFF) analysis based on a commercially available modified 2-point-Dixon (mDixon) water-fat separation method. We hypothesize that magnetic resonance (MR) imaging can reliably measure BAT regardless of the cold-induced metabolic activation, with BAT having a significantly higher water and iron content compared to WAT., Material and Methods: The supraclavicular area of 13 volunteers was studied on 3T PET-MRI scanner using T2* relaxation time and SFF mapping both during cold exposure and at ambient temperature; and 18 F-FDG PET during cold exposure. Volumes of interest (VOIs) were defined semiautomatically in the supraclavicular fat depot, subcutaneous WAT and muscle., Results: The supraclavicular fat depot (assumed to contain BAT) had a significantly lower SFF and fat T2* relaxation time compared to subcutaneous WAT. Cold exposure did not significantly affect MR-based measurements. SFF and T2* values measured during cold exposure and at ambient temperature correlated inversely with the glucose uptake measured by 18 F-FDG PET., Conclusions: Human BAT can be reliably and safely assessed using MRI without cold activation and PET-related radiation exposure., (Copyright © 2017 Elsevier Inc. All rights reserved.)