Search PubMed⌕ Search

Biomedical subjects

R J Doyle

Publications and source records attributed to R J Doyle.

167 records · Page 10Linked to original sources
PubMedDate not supplied

Zonal turnover of cell poles of Bacillus subtilis.

Turnover of cell walls of Bacillus subtilis occurs in three distinct phases: a lag phase, a relatively rapid phase persisting for 2-3 generations and a much slower phase continuing for several additional generations. A lectin probe revealed that cell pole material was lost during the slow phase of turnover and that the loss of wall occurred in zones, beginning at the cylinder-pole junction and continuing to the cell tip. This is in contrast to cell wall turnover in cylinders where turnover occurs randomly at many surface sites.

Acetylglucosamine↗
PubMedDate not supplied

The nature of salicylate inhibition of sugar transport in yeast.

A study was made in yeast of the cellular site associated with inhibition of sugar transport by salicylate. Time-course and stereospecificity studies were done on the uptake of salicylic acid (sal), meta-hydroxybenzoic acid (m-OH), D-glucose (gluc) and 3-0-methyl-D-glucose (3-OMG) at 20 and 30 degrees C. Sal added simultaneously with 3-OMG had little effect on initial uptake rates of the latter. Inhibition of 3-OMG transport occurred only after appreciable uptake of sal. Rates of glucose utilization in cells preincubated with sal increased with time despite increased drug in the medium as sal decreased in the cells. Benzoic acid also inhibited 3-OMG transport. m-OH or para-hydroxybenzoic acid entered cells but neither substance inhibited 3-OMG transport nor affected the inhibition by sal of 3-OMG transport. Benzyl and salicyl alcohols had no effect on 3-OMG transport. The results indicate a stereospecific binding site or sites for sal located in the cell interior and associated with inhibition of sugar transport. The known inhibition of sugar transport by sal in susceptible mammalian cells, including human cells, may also occur through binding of sal to intracellular, stereospecific sites.

3-O-Methylglucose↗
PubMedDate not supplied

How does a Bacillus split its septum right down the middle?

This is a speculative paper which considers the possible ways that Gram-positive cells might employ to achieve an even thickness of the two daughter poles resulting from the fission of the cross-wall. The first is that the protonmotive force generated by the extrusion of protons at the cytoplasmic membrane acts to inhibit autolysins to a distance of about 25 nm. The second has to do with the stresses that develop as the poles form. On the tacit assumption that the autolysins will function faster when their substrates are under tension, it is shown how this, too, can lead to even bisection of the cross-wall. These possibilities are not alternative, both probably function.

Bacillus↗
PubMedDate not supplied

Interactions between listeriae and lectins.

Interactions between members of the genus Listeria and lectins are described. L. monocytogenes was shown to be heterogenous with respect to agglutination by lectins. L. monocytogenes serotype 4b had a pattern of lectin binding distinct from the other listeriae. Titration of the listeriae with lectins proved to be useful in further distinguishing serotype 4b. The results show that lectins may provide useful probes as diagnostic reagents for listeriae.

Agglutination↗