Biodegradable plastics are those that can be completely degraded in landfills, composters or sewage treatment plants by the action of naturally occurring micro-organisms. Truly biodegradable plastics leave no toxic, visible or distinguishable residues following degradation. Their biodegradability contrasts sharply with most petroleum-based plastics, which are essentially indestructible in a biological context. Because of the ubiquitous use of petroleum-based plastics, their persistence in the environment and their fossil-fuel derivation, alternatives to these traditional plastics are being explored. Issues surrounding waste management of traditional and biodegradable polymers are discussed in the context of reducing environmental pressures and carbon footprints. The main thrust of the present review addresses the development of plant-based biodegradable polymers. Plants naturally produce numerous polymers, including rubber, starch, cellulose and storage proteins, all of which have been exploited for biodegradable plastic production. Bacterial bioreactors fed with renewable resources from plants – so-called ‘white biotechnology’ – have also been successful in producing biodegradable polymers. In addition to these methods of exploiting plant materials for biodegradable polymer production, the present review also addresses the advances in synthesizing novel polymers within transgenic plants, especially those in the polyhydroxyalkanoate class. Although there is a stigma associated with transgenic plants, especially food crops, plant-based biodegradable polymers, produced as value-added co-products, or, from marginal land (non-food), crops such as switchgrass (Panicum virgatum L.), have the potential to become viable alternatives to petroleum-based plastics and an environmentally benign and carbon-neutral source of polymers.

▪ Abstract Plant cells are unique in that they contain four species of α-ketoacid dehydrogenase complex: plastidial pyruvate dehydrogenase, mitochondrial pyruvate dehydrogenase, α-ketoglutarate (2-oxoglutarate) dehydrogenase, and branched-chain α-ketoacid dehydrogenase. All complexes include multiple copies of three components: an α-ketoacid dehydrogenase/decarboxylase, a dihydrolipoyl acyltransferase, and a dihydrolipoyl dehydrogenase. The mitochondrial pyruvate dehydrogenase complex additionally includes intrinsic regulatory protein-kinase and -phosphatase enzymes. The acyltransferases form the intricate geometric core structures of the complexes. Substrate channeling plus active-site coupling combine to greatly enhance the catalytic efficiency of these complexes. These α-ketoacid dehydrogenase complexes occupy key positions in intermediary metabolism, and a basic understanding of their properties is critical to genetic and metabolic engineering. The current status of knowledge of the biochemical, regulatory, structural, genomic, and evolutionary aspects of these fascinating multienzyme complexes are reviewed.

Summary: The phenomenon of hybrid vigor (heterosis) has long been harnessed by plant breeders to improve world food production. However, the changes that are essential for heterotic responses and the mechanisms responsible for heterosis remain undefined. Large increases in biomass and yield in high‐heterosis hybrids suggest that alterations in bioenergetic processes may contribute to heterosis. Progeny from crosses between various inbred lines vary in the extent of vigor observed. Field‐grown maize F₁ hybrids that consistently exhibited either low or high heterosis across a variety of environments were examined for changes in proteins that may be correlated with increased plant vigor and yield. Unpollinated ears at the time of flowering (ear shoots) were selected for the studies because they are metabolically active, rich in mitochondria, and the sizes of the ears are diagnostic of yield heterosis. Total protein and mitochondrial proteomes were compared among low‐ and higher‐heterosis hybrids. Two‐dimensional difference gel electrophoresis was used to identify allelic and/or isoform differences linked to heterosis. Identification of differentially regulated spots by mass spectrometry revealed proteins involved in stress responses as well as primary carbon and protein metabolism. Many of these proteins were identified in multiple spots, but analysis of their abundances by label‐free mass spectrometry suggested that most of the expression differences were due to isoform variation rather than overall protein amount. Thus, our proteomics studies suggest that expression of specific alleles and/or post‐translational modification of specific proteins correlate with higher levels of heterosis.

Binge ethanol in rats after chronic ethanol exposure augments necrosis and steatosis in the liver. In this study, two-dimensional gel electrophoresis proteomic profiles of liver of control, chronic ethanol, control-binge, and chronic ethanol- binge were compared.

Plant Gene Register titles for [98-165][1] to [98-174][1] appear below. The sequences have been deposited in GenBank and the articles listed online through the World Wide Web. To cite an electronic Plant Gene Register article as a bibliographic reference, follow the style given below: Lalanne E,