Reward perception guides all aspects of animal behavior. However, the relationship between the perceived value of a reward, the latent value of a reward, and the behavioral response remains unclear. Here we report that, given a choice between two sweet and chemically similar sugars-L- and D-arabinose-Drosophila melanogaster prefers D- over L- arabinose, but forms long-term memories of L-arabino...

BACKGROUND On the basis of results in cell cultures, rodents, and pigs, l-arabinose may inhibit intestinal sucrase activity and thereby delay sucrose digestion. OBJECTIVE The objective was to investigate the dose-response effects of l-arabinose on intestinal sucrase activity in vitro and glucose tolerance, appetite, and energy intake in humans. DESIGN In vitro, Caco-2 cells were cultured fo...

3-Dehydroshikimic acid is a hydroaromatic precursor to chemicals ranging from L-phenylalanine to adipic acid. The concentration and yield of 3-dehydroshikimic acid microbially synthesized from various carbon sources has been examined under fed-batch fermentor conditions. Examined carbon sources included D-xylose, L-arabinose, and D-glucose. A mixture consisting of a 3:3:2 molar ratio of glucose...

Most mutations at position 15 in the N-terminal arm of the regulatory protein AraC leave the protein incapable of responding to arabinose and inducing the proteins required for arabinose catabolism. Mutations at other positions of the arm do not have this behavior. Simple energetic analysis of the interactions between the arm and bound arabinose do not explain the uninducibility of AraC with mu...

Bacteria such as Escherichia coli will often consume one sugar at a time when fed multiple sugars, in a process known as carbon catabolite repression. The classic example involves glucose and lactose, where E. coli will first consume glucose, and only when it has consumed all of the glucose will it begin to consume lactose. In addition to that of lactose, glucose also represses the consumption ...

The permeability characteristics of D- and L-xylose and D- and L-arabinose have been compared in isolated intact rat diaphragm muscle preparations, in the absence and presence of exogenous insulin. In the absence of added insulin, these pentoses distribute in less than a third of the total cell water. In the presence of added insulin, intracellular distribution of all these pentoses is increase...

Changes in neutral sugar, uronic acid, and protein content of tomato (Lycopersicon esculentum Mill) cell walls during ripening were characterized. The only components to decline in amount were galactose, arabinose, and galacturonic acid. Isolated cell walls of ripening fruit contained a water-soluble polyuronide, possibly a product of in vivo polygalacturonase action. This polyuronide and the o...

An "in vivo" assay for the detection of mutants negative to CRM (cross-reacting material) is described. l-Arabinose-negative mutants of Escherichia coli B/r were grown on Casamino Acids-l-arabinose plates to which a 3-ml agar layer, containing antiserum to the l-arabinose-binding protein (ABP), had been applied. After incubation and partial lysis of the clones "in situ," the plates were refrige...

Genes placed under the control of the arabinose-inducible araBAD promoter (P(BAD)) of Escherichia coli are expressed in an all-or-none fashion, in which the percentage of induced cells in the population, rather than the degree of induction in individual cells, varies with the concentration of arabinose in the culture medium. Previous work showed that all-or-none gene expression from P(BAD) was ...

We isolated a pollen-defective mutant, collapsed abnormal pollen1 (cap1), from Tos17 insertional mutant lines of rice (Oryza sativa). The cap1 heterozygous plant produced equal numbers of normal and collapsed abnormal grains. The abnormal pollen grains lacked almost all cytoplasmic materials, nuclei, and intine cell walls and did not germinate. Genetic analysis of crosses revealed that the cap1...