The Escherichia coli serine chemoreceptor takes on a simple membrane topology with two transmembrane segments separating cytoplasmically disposed N and C termini from a central periplasmic domain. We investigated the role of the small N-terminal cytoplasmic domain in membrane insertion using alkaline phosphatase gene fusions. Mutations eliminating the positive charge of the domain altered inser...

We developed a high-throughput quantitative capillary assay and demonstrated that Pseudomonas putida strains F1 and PRS2000 were attracted to cytosine, but not thymine or uracil. In contrast, Pseudomonas aeruginosa PAO1 was not chemotactic to any pyrimidines. Chemotaxis assays with a mutant strain of F1 in which the putative methyl-accepting chemotaxis protein-encoding gene Pput_0623 was delete...

Strains carrying mutations in the maltose system of Escherichia coli were assayed for maltose taxis, maltose uptake at 1 and 10 muM maltose, and maltose-binding activity released by osmotic shock. An earlier conclusion that the metabolism of maltose is not necessary for chemoreception is extended to include the functioning of maltodextrin phosphorylase, the product of malP, and the genetic cont...

To investigate the channels and neurotransmitters in the ventrolateral medulla (VLM) oblongata that are responsible for the maintenance of sympathetic tone and cardio-respiratory reflex regulation. Microinjections of excitant amino acid (glutamate, 100 nl, 100 mM), calcium channel blockers, agonists and antagonists were made throughout the VLM in anaesthetized rats. Arterial blood pressure, sym...

To investigate the channels and neurotransmitters in the ventrolateral medulla (VLM) oblongata that are responsible for the maintenance of sympathetic tone and cardio-respiratory reflex regulation. Microinjections of excitant amino acid (glutamate, 100 nl, 100 mM), calcium channel blockers, agonists and antagonists were made throughout the VLM in anaesthetized rats. Arterial blood pressure, sym...