Sucrose, a glucose-fructose disaccharide, is the main sugar transported in the phloem of most plants and is the origin of most of the organic matter. Upon arrival in sink tissues, the sucrose must be cleaved by invertase or sucrose synthase. Both sucrose-cleaving enzymes yield free fructose, which must be phosphorylated by either fructokinase (FRK) or hexokinase (HXK). The affinity of FRK to fr...

The Internet and the Grid are changing the face of high performance computing. Rather than tightly-coupled SPMD-style components running in a single cluster, on a parallel machine, or even on the Internet programmed in MPI, applications are evolving into sets of cooperating components scattered across diverse computational elements. These components may run on diierent operating systems and har...

Recent developments have altered our view of molecular mechanisms that determine sink strength, defined here as the capacity of non-photosynthetic structures to compete for import of photoassimilates. We review new findings from diverse systems, including stems, seeds, flowers, and fruits. An important advance has been the identification of new transporters and facilitators with major roles in ...

The concept that photosynthetic flux is influenced by the accumulation of photo-assimilate persisted for 100 years before receiving any strong experimental support. Precise analysis of the mechanisms of photosynthetic responses to sink activity required the development of a battery of appropriate molecular techniques and has benefited from contemporary interest in the effects of elevated CO2 on...

Aerated soils form the second largest sink for atmospheric CH4 A near-complete genome of uncultured upland soil cluster Gammaproteobacteria that oxidize CH4 at <2.5 ppmv was obtained from incubated Antarctic mineral cryosols. This first genome of high-affinity methanotrophs can help resolve the mysteries about their phylogenetic affiliation and metabolic potential.

The concept of source and sink strength is presently well-recognized and accepted by the scientific community as a pertinent approach describing the mechanisms of carbohydrate partitioning into the different and competing organs at a whole plant or canopy scales. Sink–source relationships have a clear role in the size of sink organs. Besides the effect on organ size, sink/source ratio might also...

A unique sink orientation (USO) is an orientation of the n-dimensional cube graph (n-cube) such that every face (subcube) has a unique sink. The number of unique sink orientations is nΘ(2 n) [13]. If a cube orientation is not a USO, it contains a pseudo unique sink orientation (PUSO): an orientation of some subcube such that every proper face of it has a unique sink, but the subcube itself hasn...

Carotenoids are a group of pigments that are essential to human diets. An increasing interest in carotenoids as a nutritional source of vitamin A and health-promoting compounds has prompted the recent progress in metabolic engineering of carotenogenesis in food crops. Current strategies have been mainly focused on manipulating genes encoding carotenogeic enzymes. In many cases, it is difficult ...

The proposal that the genetic code was formed on the basis of (proto)tRNA Dimer-Directed Protein Synthesis is reviewed and updated. The tRNAs paired through the anticodon loops are an indication on the process. Dimers are considered mimics of the ribosomes-structures that hold tRNAs together and facilitate the transferase reaction, and of the translation process-anticodons are at the same time ...