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Biomedical subjects

Mark Taylor

Publications and source records attributed to Mark Taylor.

At least 19 recordsLinked to original sources
PubMed2006

Recruitment predicament. Tenet settles with feds for $21 million in kickback case, but hospitals still wait for clear guidance on what's allowed.

Under a $21 million settlement between Tenet Healthcare Corp. and the federal government, there will not be a third trial for Alvarado or its former chief. Tom McNamara, left, the lawyer who represented former Alvarado CEO Barry Weinbaum, says the exec is elated to hear that. The industry, on the other hand, still has reservations. It wants clear guidance on what is legal in physician recruiting.

California↗
PubMed2006

Tomato aromatic amino acid decarboxylases participate in synthesis of the flavor volatiles 2-phenylethanol and 2-phenylacetaldehyde.

An important phenylalanine-derived volatile compound produced by plants is 2-phenylethanol. It is a major contributor to flavor in many foods, including fresh fruits, such as tomato, and an insect-attracting scent in roses and many other flowers. Despite the centrality of 2-phenylethanol to flavor and fragrance, the plant genes responsible for its synthesis have not been identified. Here, we describe a biosynthetic pathway for 2-phenylethanol and other phenylalanine-derived volatiles in tomato fruits and a small family of decarboxylases (LeAADC1A, LeAADC1B, and LeAADC2) that can mediate that pathway's first step. These enzymes each catalyze conversion of phenylalanine to phenethylamine and tyrosine to tyramine. Although tyrosine is the preferred substrate in vitro, phenylalanine levels in tomato fruits far exceed those of tyrosine, indicating that phenylalanine is a physiological substrate. Consistent with this view, overexpression of either LeAADC1A or LeAADC2 in transgenic tomato plants resulted in fruits with up to 10-fold increased emissions of the products of the pathway, including 2-phenylacetaldehyde, 2-phenylethanol, and 1-nitro-2-phenylethane. Further, antisense reduction of LeAADC2 significantly reduced emissions of these volatiles. Besides establishing a biosynthetic route, these results show that it is possible to change phenylalanine-based flavor and aroma volatiles in plants by manipulating expression of a single gene.

Acetaldehyde↗