Effect of medium salinity on some chemical constituents of two halophilic Bacillus spp. From Saudi Arabia.

The cell envelope amino acids of two moderately halophilic Bacillus isolates (BST and BSF) varied according to medium salinity. Cystine and proline were mostly effected. In both isolates growing in the presence of 6 and 18% NaCl there were more dicarboxylic amino acids than basic amino acids which makes the cell envelope proteins quite acidic. The concentrations of the cell-associated cations (Na+, K+, and Mg2+) were high in both isolates, and varied according to the NaCl concentration. The two isolates contained glucosamine and muramic acid in their cell walls. The amounts of these two sugar derivatives, however, varied with the NaCl concentration. Thin-layer chromatography of phospholipids revealed the presence of cardiolipins, phosphatidylglycerols and phosphatidylethanolamines in the two isolates irrespective of medium salinity. Phosphatidylglycerols and the phosphatidylethanolamines increased on increasing the NaCl concentration of the growth medium. Lysophosphatidylglycerols were detected only in the 6% grown BST cells. Unidentified phospholipids designated X1 (in isolates BSF and BST), X2 (in isolate BST) and X3 (in isolate BSF) were also detected; the concentrations of X1 and X3 were salinity dependent

Role of pre-incubation in non-selective medium in recovery of Staphylococcus aureus from swimming pools and beaches

Staphylococcus aureus was isolated from eleven open swimming pools and eleven swimming beaches in certain areas of Saudi Arabia. Pre-incubation of the water samples in a non-selective medium prior to their growth in the selective medium increased the rate of recovery over that of direct plating on the selective medium. The average increase was from 20.68% to 46.1% for pools and from 32.7% to 37.3% for beaches. Pre-incubation, therefore, is very important for the pool water which appears to contain more stressed bacteria

Comparison of heat treatment and ethanol treatment procedures used to isolate sporeforming bacteria and identification of a food poisoning-causing bacteria as Bacillus cereus using ethanol treatment.

Abstract Ethanol treatment and heat treatment procedures for the isolation of sporeforming bacteria were compared. Heat treatment was not able to eliminate all the vegetative cells which were present at high concentration, whereas ethanol treatment eliminated all the vegatative cells with some activation of spores germination. An application of ethanol treatment for the investigation of a food poisoning outbreak was discussed. Fifteen individuals were having a picnic. Seven of them ate fried rice with the lunch meal of the second day. The fried rice was made from a leftover boiled rice prepared during the first day. All seven individuals who had eaten from the fried rice had nausea, abdominal cramps, diarrhea and vomiting, whereas the others who did not eat had no symptoms. Bacillus cereus and B..licheniformis were isolated from the leftover boiled rice and for several discussed reasons the food poisoning causing agent was iden-tified as B. cereus

A permeability Mutant of Yersinia pestis with Increased Susceptibility to Phagocytosis which Retains Potential for Intraphagocytic Growth and Virulence.

Abstract Gentian violet resistance was used to select mutants of Yersinia pestis with altered cell envelope permeability. Mutants in one class lacked the 6 and 61 megadalton (Mdal) plasmids, but retained the 47 Mdal plasmid associated with calcium dependence. Mutants in a second class retained all three plasmids. One mutant in the latter class, EV76S7, lacked major outer membrane protein J and yielded reduced levels of minor outer membrane proteins A and C. Protein J is known to interact differently with lipopolysaccharide (LPS) from cells bearing and cells lacking the 47 Mdal plasmid following growth at 37 degrees C. The 47 Mdal plasmid is known to influence gentian violet uptake, novobiocin sensitivity, susceptibility to phagocytosis, the growth in macrophages and the virulence of Y. pestis. Gentian violet uptake was lower and novobiocin sensitivity higher in the mutant than in the parental strain, but the underlying effects of the 47 Mdal plasmid on these parameters had not changed. EV76S7 cells were phagocytized to a greater extent than the parental cells following growth at 37 degrees C, but survival and growth within peritoneal phagocytes and the LD50's of cells with and without the 47 Mdal plasmid were not altered by the loss of protein J, we conclude that protein J--LPS interactions are not required for virulence, and that the reduced virulence of cells lacking the 47 Mdal plasmid does not result from the altered protein J--LPS interactions which are known to result from loss of the plasmid

Antibacterial Activity of Commiphora quadricincta From Saudi Arabia.

Abstract Commiphora quadricincta (Schweinf ex. Engl.) has a resin-gum that is widely used as a folk medicine in Saudi Arabia. Extracts of the resin-gum, leaves and roots have been studied for their antibacterial activity. The results clearly show that the toluene-methanol extract of the leaves and roots has antibacterial activity against Yersinia enterocolitica and Staphylococcus epidermidis, whereas the toluene-methanol extract of the resin gum has activity against Escherichia coli. The antibacterial activity of the resin gum is dependent upon the solvent used. Petroleum ether is the best solvent followed by alcohols (ethanol and methanol, respectively). The petroleum ether extract of the resin-gum has activity against three out of four of the species studied namely, Staphylococcus aureus, S. epidermidis and E. coli. The ethanol extract has antibacterial activity against Y. enterocolitica and S. epidermidis and the methanol extract has activity against E. coli and S. epidermidis. Diethyl ether has an activity pattern similar to ethanol, but it was less potent. Benzene and chlorofo~ extracts have similar activity against E. coli only. The water extract of resin-gum had an inhibitory influence both in vitro and in vivo against bacterial viability. Key Words: Antibacterial, Activity, Commiphora. Quadricincta

Effect of Some Physical and Chemical Factors on the Bactericidal Acitivity of Human Lactoferrin and Transferrin Against Yersinia pseudotuberculosis.

Abstract The iron-chelating proteins lactoferrin and transferrin have been shown to be bactericidal for a variety of organisms. In this study, the effect of pH, temperature, their concentration, and magnesium and calcium on the bactericidal activity against Yersinia pseudotuberculosis was investigated. The bactericidal activity of lactoferrin was higher at acid pH, whereas, the bactericidal activity of transferrin was higher at alkaline pH. Both were not efficient at 4°, 15° and 25°C, but they were efficient at 37°C. Lactoferrin, but not transferrin, was very efficient at 42°C. The activity of both were time and concentration dependent. Calcium did not effect their activity up to 60 mM, whereas, magnesium reduced the activity of lactoferrin only