Protein turnover is a key component in cellular homeostasis; however, there is little quantitative information on degradation kinetics for individual plant proteins. We have used (15)N labeling of barley (Hordeum vulgare) plants and gas chromatography-mass spectrometry analysis of free amino acids and liquid chromatography-mass spectrometry analysis of proteins to track the enrichment of (15)N ...

The loss of green coloration via chlorophyll (Chl) degradation typically occurs during leaf senescence. To date, many Chl catabolic enzymes have been identified and shown to interact with light harvesting complex II to form a Chl degradation complex in senescing chloroplasts; this complex might metabolically channel phototoxic Chl catabolic intermediates to prevent oxidative damage to cells. Th...

Peroxidation is indicated by several physiological param eters: (1) leakage o f cell mem branes and production o f short-chain hydrocarbons, (2) degradation o f cell constituents, (3) inhibi­ tion o f chlorophyll biosynthesis, (4) accum ulation o f tetrapyrroles (pro toporphyrin IX), (5) inhibition o f protoporphyrinogen oxidase by peroxidizers, (6) alleviation o f peroxidation by inhibitors o ...

Primitive photosynthetic microorganisms, either dormant or dead, may remain today on the martian surface, akin to terrestrial cyanobacteria surviving endolithically in martian analog sites on Earth such as the Antarctic Dry Valleys and the Atacama Desert. Potential markers of martian photoautotrophs include the red edge of chlorophyll reflectance spectra or fluorescence emission from systems of...

Abstract Stream biofilms are among the first to react environmental degradation, since their structural and functional characteristics tightly linked physicochemical variables in water sediment. The objectives of this research were study differences chlorophyll-a, bacterial density metabolism endpoints epipelic nutrient-rich streams under different physical-chemical conditions stream relation c...