Study of triacylglycerol assembly by Apiotrichum curvatum ATCC 20509 as a model system

The oleaginous yeast Apiotrichum curvatum ATCC 20509 was grown on various lipids as carbon sources. When commercial oils were used as substrates, the yeast triglyceride had a fatty acid profile similar to that of the substrate oil, but the glyceride structure was altered. The yeast did not utilize saturated free fatty acids with less than 14 carbons. An emulsion of palmitic acid was well utilized by the yeast, however stearic and arachidic acid emulsions gave very limited and no growth, respectively. Palmitic and stearic acids were extensively desaturated before being deposited in the yeast triglyceride. Oleic acid supported very good yeast growth; eicosenoic acid supported limited growth; erucic acid gave very poor growth. The yeast grew on petroselinic acid and deposited it extensively in its triglyceride. When the medium was supplemented with 1000 ppm butylated hydroxyanisole, linoleic and linolenic acids supported excellent growth and lipid accumulation. The yeast deposited ricinoleic, eleostearic and vernolic acids in its triglyceride when the yeast was grown on triglycerides containing these fatty acids, but the yeast triglyceride contained less of these fatty acids than were found in the substrate oils. When crambe oil was used as a carbon source for the yeast, fatty acids with 20 or more carbons were concentrated in the residual substrate oil. The yeast incorporated very little of the cholesterol in the growth medium into its depot fats. Oleic-linoleic mixtures in various combinations gave good growth and yielded triglycerides with an extensive range of acyl compositions. Plots of the percentage of oleate and linoleate on the glycerol positions vs. the percentage in the whole yeast triglyceride gave linear relations over most of the range for each acyl group. A simple mathematical model of triglyceride assembly was proposed to explain this observation

The impact of comorbid anxiety on quantitative EEG heterogeneity in children with attention-deficit/hyperactivity disorder

ObjectiveThe objective of this study was to compare quantitative electroencephalography (Q-EEG) characteristics of children with Attention-deficit/hyperactivity disorder (ADHD), taking into account the presence of a comorbidity for anxiety disorder. It also sought to investigate the impact of comorbid anxiety on the Q-EEG heterogeneity of children with ADHD.MethodA total of 141 children with ADHD but without comorbid anxiety (ADHD-Only), 25 children with a comorbidity for anxiety disorder (ADHD-ANX) and 43 children in the control group were assessed. To compare Q-EEG characteristics between groups, we performed ANCOVA (Analysis of Covariance) on relative power and theta/beta ratio (TBR) controlling for covariates such as age, sex, and FSIQ. Relative power values from 19 electrodes were averaged for three regions (frontal, central and posterior). Furthermore, cluster analysis (Ward’s method) using the squared Euclidian distance was conducted on participants with ADHD to explore the impact of anxiety on the heterogeneity of Q-EEG characteristics in ADHD.ResultsThere were no significant group differences in cognitive and behavioral measures. However, significant differences between groups were observed in the theta values in the central region, and the beta values in the frontal, central and posterior regions. In post hoc analyses, It was found that the ADHD-ANX group has significantly higher beta power values than the ADHD-Only group in all regions. For the theta/beta ratio, the ADHD-Only group had significantly higher values than the ADHD-ANX group in frontal, central and posterior regions. However, the control group did not show significant differences compared to both the ADHD-Only and ADHD-ANX group. Through clustering analysis, the participants in the ADHD-Only and ADHD-ANX groups were classified into four clusters. The ratios of children with comorbidities for anxiety disorder within each cluster were significantly different (χ2 = 10.018, p = 0.019).ConclusionAttention-deficit/hyperactivity disorder children with comorbid anxiety disorder showed lower theta power in the central region, higher beta power in all regions and lower TBR in all regions compared to those without comorbid anxiety disorder. The ratios of children with comorbidities for anxiety disorder within each cluster were significantly different

Direct Determination of MCPD Fatty Acid Esters and Glycidyl Fatty Acid Esters in Vegetable Oils by LC–TOFMS

Analysis of MCPD esters and glycidyl esters in vegetable oils using the indirect method proposed by the DGF gave inconsistent results when salting out conditions were varied. Subsequent investigation showed that the method was destroying and reforming MCPD during the analysis. An LC time of flight MS method was developed for direct analysis of both MCPD esters and glycidyl esters in vegetable oils. The results of the LC–TOFMS method were compared with the DGF method. The DGF method consistently gave results that were greater than the LC–TOFMS method. The levels of MCPD esters and glycidyl esters found in a variety of vegetable oils are reported. MCPD monoesters were not found in any oil samples. MCPD diesters were found only in samples containing palm oil, and were not present in all palm oil samples. Glycidyl esters were found in a wide variety of oils. Some processing conditions that influence the concentration of MCPD esters and glycidyl esters are discussed

Study of triacylglycerol assembly by Apiotrichum curvatum ATCC 20509 as a model system

The oleaginous yeast Apiotrichum curvatum ATCC 20509 was grown on various lipids as carbon sources. When commercial oils were used as substrates, the yeast triglyceride had a fatty acid profile similar to that of the substrate oil, but the glyceride structure was altered. The yeast did not utilize saturated free fatty acids with less than 14 carbons. An emulsion of palmitic acid was well utilized by the yeast, however stearic and arachidic acid emulsions gave very limited and no growth, respectively. Palmitic and stearic acids were extensively desaturated before being deposited in the yeast triglyceride. Oleic acid supported very good yeast growth; eicosenoic acid supported limited growth; erucic acid gave very poor growth. The yeast grew on petroselinic acid and deposited it extensively in its triglyceride. When the medium was supplemented with 1000 ppm butylated hydroxyanisole, linoleic and linolenic acids supported excellent growth and lipid accumulation. The yeast deposited ricinoleic, eleostearic and vernolic acids in its triglyceride when the yeast was grown on triglycerides containing these fatty acids, but the yeast triglyceride contained less of these fatty acids than were found in the substrate oils. When crambe oil was used as a carbon source for the yeast, fatty acids with 20 or more carbons were concentrated in the residual substrate oil. The yeast incorporated very little of the cholesterol in the growth medium into its depot fats. Oleic-linoleic mixtures in various combinations gave good growth and yielded triglycerides with an extensive range of acyl compositions. Plots of the percentage of oleate and linoleate on the glycerol positions vs. the percentage in the whole yeast triglyceride gave linear relations over most of the range for each acyl group. A simple mathematical model of triglyceride assembly was proposed to explain this observation.</p