Deep-rough mutants

Clearly, the isolation and characterization of a variety of deep rough mutants of M. avium represent a major development in the goal of elucidating the biosynthetic pathway of the GPLs. They also provide the means to examine the roles of GPLs in the disease processes induced by M. avium, specifically in eliciting an immunosuppressive response.206... 

Brandenburg, K., Koch, M.H.J., Seydel, U. Phase diagramm of deep rough mutant lipopolysaccharide from Salmonella minnesota R595. J Struct Biol 108 (1992) 93-106. 

Kastowsky, M., Sabisch, A., Gutberlet, T., Bradaczek, H. Molecular modelling of bacterial deep rough mutant lipopolysaccharide of Escherichia coli, Eur J Biochem 197 (1991) 707-716. 

Kanipes, M.I., Holder, L.C., Corcoran, A.T., Moran, A.P., Guerry, P. A deep-rough mutant of Campylobacter jejuni 81-176 is non-invasive for intestinal epithelial cells. Infect Immun 72 (2004) 2452-2455. 

Uptake of the parabens probably proceeds by a general dissolution of an ester into the cell with no specific binding sites at the cell surface. In the deep rough mutants, the increased sensitivity to the parabens probably results from the appearance of phospholipid patches at the cell surface which aid in penetration of the parabens and especially of the most hydrophobic one (the Bu ester). A similar mechanism is likely to account for the uptake of phenolics across the outer membrane into the cells. 

The interaction between bacterial lipopolysaccharides (EPS) and phospholipid cell membranes was studied by various physical methods of deep rough mutant EPS (ReEPS) of Escherichia coH incorporated in phospholipid bilayers as simple models of cell membranes. SS P-NMR spectroscopic analysis suggested that a substantial part of ReEPS is incorporated into l,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid bilayers when mixed multilamellar vesicles were prepared. Furthermore the lipid lateral diffusion coefficients measurements at various molar ratios of ReEPS/egg-PC/POPG indicated that the incorporated ReEPS reduces the diffusion coefficients of the phospholipids in the membrane. EUV formed by the ReEPS from Salmonella enterica, eventually in mixture with dilauroyl phosphatidylcholine (DEPC), have been prepared and characterized by DES, SANS and EPR. PFGSE NMR measurements have shown that water permeability through the lipid bilayer is low at room temperature. However, above a transition temperature centered at 30-35 °C, the water permeability increases. ... 

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