Water soluble lipid precursor contaminants in yeast culture medium ingredients

The presence of the water soluble glycerophospholipid precursors choline and inositol in culture media highly affects lipid biosynthesis and regulation thereof. We report that widely used media ingredients contain trace amounts of choline and inositol that are not mentioned on the product label, influencing experimental outcome.

Fasting stimulates 2-AG biosynthesis in the small intestine: role of cholinergic pathways

The endocannabinoids are lipid-derived signaling molecules that control feeding and energy balance by activating CB1-type cannabinoid receptors in the brain and peripheral tissues. Previous studies have shown that oral exposure to dietary fat stimulates endocannabinoid signaling in the rat small intestine, which provides positive feedback that drives further food intake and preference for fat-rich foods. We now describe an unexpectedly broader role for cholinergic signaling of the vagus nerve in the production of the endocannabinoid, 2-arachidonoyl- sn-glycerol (2-AG), in the small intestine. We show that food deprivation increases levels of 2-AG and its lipid precursor, 1,2-diacylglycerol, in rat jejunum mucosa in a time-dependent manner. This response is abrogated by surgical resection of the vagus nerve or pharmacological blockade of small intestinal subtype-3 muscarinic acetylcholine (m3 mAch) receptors, but not inhibition of subtype-1 muscarinic acetylcholine (m1 mAch). We further show that blockade of peripheral CB1 receptors or intestinal m3 mAch receptors inhibits refeeding in fasted rats. The results suggest that food deprivation stimulates 2-AG-dependent CB1 receptor activation through a mechanism that requires efferent vagal activation of m3 mAch receptors in the jejunum, which, in turn, may promote feeding after a fast.

Radioautographic visualization of incorporation of lipid precursors into anthers of Muscari comosum (L.) Mili.

Incorporation of the following lipid precursors: DL-mevalonic acid-2 ³H, ³H palmitic acid and acetic acid-³H sodium salt, into the anther cells of <i>Muscari comosum</i> (L.) Mili. has been investigated. These lipid precursors have been demonstrated to incorporate into pollen mother cells, pollen grains and the tapetum at the consecutive developmental stages. Ali used isotopes are incorporated into the cytoplasm of these cells and in the case of pollen grain the radioactivity of pollen grain wall (mainly composed of sporopellenin) is noticed. The highest radioactivity of pollen grain wall is observed after acetic acid, the lower one after palmitic acid, whereas the lowest uptake of lipid precursor occurs after mevalonic acid. In comparison with tetrad stage the distinct inrease of the cytoplasmic radioactivity of tapetum, which appears to1 accompany the labelling of pollen grain wall, seems to indicate the participation of tapetum in the formation of exine. A possible role of Ubisch bodies in the formation of pollen grain wall is discussed.