One fluorescent compound previously named TDP-2 was isolated and purified from a rice culture of Fusarium equiseti (Alaska 2-2). Mass spectral and nuclear magnetic resonance data indicated that it is a C-3'-N-acetyl derivative of fusarochromanone, a newly discovered mycotoxin. Time course studies of synthesis of these two compounds on autoclaved rice and Czapek-Dox medium enriched with soybean peptone indicated that fusarochromanone was converted to TDP-2 in the cultures. A high concentration of peptone in the liquid medium may stimulate both fusarochromanone synthesis and its conversion to TDP-2.
Understanding the timing and mechanisms of amino acid synthesis and racemization on asteroidal parent bodies is key to demonstrating how amino acids evolved to be mostly left-handed in living organisms on Earth. It has been postulated that racemization can occur rapidly dependent on several factors, including the pH of the aqueous solution. Here, we conduct nanoscale geochemical analysis of a framboidal magnetite grain within the Tagish Lake carbonaceous chondrite to demonstrate that the interlocking crystal arrangement formed within a sodium-rich, alkaline fluid environment. Notably, we report on the discovery of Na-enriched subgrain boundaries and nanometer-scale Ca and Mg layers surrounding individual framboids. These interstitial coatings would yield a surface charge state of zero in more-alkaline fluids and prevent assimilation of the individual framboids into a single grain. This basic solution would support rapid synthesis and racemization rates on the order of years, suggesting that the low abundances of amino acids in Tagish Lake cannot be ascribed to fluid chemistry.
CommentIn: Proc Natl Acad Sci U S A. 2020 Sep 15;117(37):22650-22651 PMID 32913061
CommentIn: Proc Natl Acad Sci U S A. 2020 Sep 15;117(37):22649 PMID 32913062
It was shown that under cultivation of Bacillus subtilis IMVV-7023 in the nutrient medium with glycerophosphate biologically active substances are accumulated in the culture liquid. They influence positively the seeds growth and formation of plant germs. The bacteria synthesize amino acids in this medium, their quantitative structure differs from the type of carbon nutrition and cultivation time of the cells.
During the RV-ARAON cruise, a comparative study on the biosynthesis of mycosporine-like amino acids (MAAs) was conducted for the size-fractionated phytoplankton of the Beaufort Sea (Arctic). The MAAs contents in the micro-phytoplankton community (>20?µm size) is considerably higher than that observed in the nano- (20-2?µm size) and pico-phytoplankton (