Gram-negative cell walls are strong enough to withstand ;3 atm of turgor pressure (40), tough enough to endure extreme temperatures and pHs (e.g., Thiobacillus ferrooxidans grows at a pH of '1.5) and elastic enough to be capable of expanding several times their normal surface area (41). Strong, tough, and elastic . . . the gram-negative cell wall is a remarkable structure which protects the con...

Sequence analysis of the Helicobacter pylori major sigma factor (RpoD) shows that it is highly divergent, which may be related to the marked diversity of the H. pylori chromosome. Furthermore, the rate of divergence of RpoD among other gram-negative bacteria is much greater than that among gram-positive bacteria. This suggests that RpoD from gram-negative bacteria is functionally less constrain...

71 samples of milk and dairy products were collected from 18 cities throughout Iran. 93 strains of lactic acid bacteria (LAB) were isolated and assayed against four opportunistic patho gens including E. coli, proteus and klebsiella as gram-negative and S. aureus as a gram-positive organism. All indicators (organisms) were hospital strains. Among isolated bacteria, lactobacilli (37 isolates)...

The effect of erythromycin on activated sludge bacteria according to their Gram type was investigated with 3-dimensional Confocal Laser Scanning Microscopy (CLSM) time-lapse imaging. The fluorescent stains SYTOX Green and Texas Red-X conjugate of wheat germ agglutinin stained dying bacteria and Gram(+) bacteria respectively. Time-lapse imaging allowed an understanding of the staining mechanism ...

Multidrug-resistant (MDR) Gram-negative bacteria have emerged as a serious threat to human and animal health. Bdellovibrio spp. and Micavibrio spp. are Gram-negative bacteria that prey on other Gram-negative bacteria. In this study, the ability of Bdellovibrio bacteriovorus and Micavibrio aeruginosavorus to prey on MDR Gram-negative clinical strains was examined. Although the potential use of p...

In recent years, a group of antibacterial proteins produced by gram-positive bacteria have attracted great interest in their potential use as food preservatives and as antibacterial agents to combat certain infections due to gram-positive pathogenic bacteria. They are ribosomally synthesized peptides of 30 to less than 60 amino acids, with a narrow to wide antibacterial spectrum against gram-po...

Lacticin Q, a lactococcal pore-forming bacteriocin, shows activity toward Gram-positive bacteria but not Gram-negative bacteria. Lacticin Q did not induce permeability of the outer membrane of Gram-negative bacteria. Experiments using model membranes containing outer membrane components suggested that lacticin Q binds to the outer membrane of Gram-negative bacteria but is unable to penetrate it...