Robin J Rowbury

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The transfer of cells of Salmonella enteritidis phage type 4 from 20 to 37-46 degrees C resulted in marked increases in acid and heat tolerance. The former was maximized within 5 to 15 min of the shift and was largely independent of protein synthesis. In contrast, induction of increased heat tolerance was slower, requiring more than 60 min to be completed,(More)
In a comparative study of different Salmonella enteritidis phage type 4 isolates we found that those isolates with enhanced heat tolerance also survived better than isolates that were heat sensitive either at pH 2.6, in 10 mM H2O2, or on surfaces. Culture to the stationary phase increased the heat tolerance of all isolates and the acid and H2O2 tolerance of(More)
BIOCHEMICAL and genetical experiments with methionine auxothrophs of Salmonella typhimurium (SMITH 1961 ; SMITH and CHILDS 1966; CHILDS and SMITH unpublished) have resulted in the recognition of six structural genes ( m t A , B, C, E, F and H ) concerned with well defined sequential steps in the biosynthesis of methionine (Figure 1) . Mutants of another(More)
Environmental factors such as temperature, pH and nutrient level affect enterobacterial acid sensitivity, as do the presence of phosphate and Na+ and the extent of aeration. The mechanisms governing these effects are partially understood and the involvement of phoE, fur and atp in acid tolerance, of phoE, envZ, tonB, (p)ppGpp and cAMP in salt-induced acid(More)
The introduction of the F-like resistance plasmid R124 into an ompC mutant of Escherichia coli K12 conferred altered sensitivity to a wide range of inhibitory agents. Sensitivity to ampicillin, chloramphenicol, ethionine, copper ions, deoxycholate, two fatty acids and colicins L and M was decreased by the plasmid. In contrast the plasmid-bearing ompC(More)
Several metabolites and salts including glucose, L-glutamate, L-aspartate, FeCl3, KCl and L-proline induce acid tolerance at neutral external pH (pHo) in log phase Escherichia coli. For induction by glucose and L-glutamate, the processes are independent of integration host factor (IHF), H-NS, CysB, ferric uptake regulator (Fur) and RelA. For most of the(More)
Responses induced by cold or heat are triggered following detection of temperature changes by specific sensing molecules, complexes or structures. Low temperature responses are often induced following sensing of cold-induced falls in membrane fluidity, such changes turning-on or -off enzymic activities in membrane proteins, although ribosomes and DNA may(More)
Escherichia coli shifted from external pH (pH(O)) 7.0 to pH(O) 8.5-9.5 rapidly becomes tolerant to pH(O) 10.0-11.5, induction of tolerance (alkali habituation) being dependent on periplasmic or external alkalinization with either NaOH or KOH. Induction needs protein synthesis and makes organisms resistant to DNA damage by alkali and better able to repair(More)
The following evidence supports the view that a temperature-sensitive mutant of Salmonella typhimurium (11 G) is defective in DNA synthesis initiation: a) the increment in DNA synthesis at 38° is abolished by prior completion of rounds of replication at 25°. b) The extent of the increment at 38° is greatly increased by prior growth in the presence of a DNA(More)
Mercury-resistant bacteria isolated from the oral cavities of children carried one of two types of merA gene that appear to have evolved from a common ancestor. Streptococcus oralis, Streptococcus mitis and a few other species had merA genes that were very similar to merA of Bacillus cereus strain RC607. Unlike the B. cereus RC607 merA gene, however, the(More)