PubMed Health⌕ Search

Biomedical subjects

R A Weidhase

Publications and source records attributed to R A Weidhase.

6 recordsLinked to original sources
PubMed1991

In vivo utilization of N-(phosphonomethyl)-anilines and related substances by Pseudomonas spec. GS.

Utilization of various phosphonates as source for phosphorus by the glyphosate degrading strain Pseudomonas spec. GS was investigated. Metabolites of phosphonate degradation were characterized indicating the cleavage of the C-P-bound as primary step of breakdown. The phosphonate N-(phosphonomethyl)-4'-nitroazobenzene-4-amine (azophon) was characterized as a suitable substrate for detection of C-P-bond splitting activity in vivo. Pseudomonas cells permeabilized by toluene treatment were also capable of phosphonate degradation whereas no in vitro activity of a putative C-P-bond cleaving enzyme was detectable after cell disruption.

Aniline Compounds↗
PubMed1990

[Glyphosate utilization by Pseudomonas spec. GS].

Pseudomonas spec. GS grown in the presence of 14C-labelled glyphosate metabolizes the herbicide to inorganic phosphate as well as in respect of utilization of the C-skeleton. Furthermore it was shown that the primary step of degradation is the breakdown of the C-P-bond, because sarcosine was found as a transient metabolite.

Amino Acids↗
PubMed1983

Peptide hydrolase activities in seedlings and hormone-treated cotyledons of pumpkin (Cucurbita pepo).

Enzymes hydrolyzing Gly-Ala-, Met-Met- and Pro-4-phenylazo-phenylamides, and N-benzoyl-L-arginine-4-nitroanilide have been identified in germinating seeds and cotyledons of pumpkin (Cucurbita pepo). The enzyme activities per cotyledon increase markedly during the germination process, but the proportion of enhancement depends on the type of enzyme species. The increase in enzyme activities is due to de novo synthesis as shown by cycloheximide treatment and is influenced by phytohormones (cytokinins and abscissic acid). In isolated cotyledons exogenous cytokinin (benzyladenine) obviously can replace the effect of the embryo as the source of endogenous hormone. Abscissic acid counteracts the cytokinin effect. It is suggested that aminopeptidases have a biological function in reserve protein degradation of the cotyledons during seed germination. Our results do not support the assumption that the embryonic axis of the growing seedling serves as a "sink" of proteolytic products resulting in an activation of peptide hydrolases in the cotyledons, but rather de novo synthesis of these enzymes seems to be controlled by substances (phytohormones) originating from the embryo.

Aminopeptidases↗