Biochemistry of Bacterial Cell Envelopes

Браун,; Hantke, Klaus

doi:10.1146/annurev.bi.43.070174.000513

Cited by 127 publications

(73 citation statements)

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“…fluorescens contain a lipopolysaccharide layer in their cell envelope (2). These results are different, however, from those obtained by Lippincott and Lippincott (5) for the Pinto bean system in which they observed no inhibitory effect with E. coli.…”

Section: Discussioncontrasting

confidence: 89%

Agrobacterium tumefaciens Site Attachment as a Necessary Prerequisite for Crown Gall Tumor Formation on Potato Discs

Glogowski

Galsky²

1978

Plant Physiol.

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The infectivity of Agrobacterium tumefaciens strain B6 was inhibited about 50% when these bacteria were inoculated on potato discs with equal viable cell counts of a weakly virulent strain of A. tumefaciens (B-48) The fact that crown gall host systems differ with respect to the degree of bacterial virulence shown by a given strain, the time it takes for tumor formation, and the size and number of tumors formed has been well established (1, 6, 7).The necessity for bacterial attachment to a specific site as a prerequisite for the formation of crown gall tumors on the primary leaves of Pinto beans and the time it takes for such attachment have been shown (5). Studies as to whether a similar type of attachment is necessary in other crown gall host systems have been limited due to the lack of another suitable quantitative bioassay for tumor formation, although the necessity for site attachment has been established for some nonquantitative host systems (8,10). With the recent development of the potato disc bioassay by Anand and Heberlein (1). we have undertaken studies which show that attachment to a specific site, which occurs in a short period of time, is a necessary prerequisite for tumor formation on potato discs.With the recent discovery that infectivity is due to the presence of a plasmid (11) found within tumor-inducing strains of Agrobacterium tumefaciens, experiments to determine the biochemical nature of the transformation process should increase in number. The need to understand more completely the nature of specific host systems for studying tumor formation takes on great importance. 2To whom reprint requests should be sent. MATERIALS AND METHODSof Northwestern University. The bacterium and yeast (which was obtained from the culture collection at the USDA Lab in Peoria) were grown for 48 hr in a medium containing 0.8% (w/v) nutrient broth, 0.1% (w/v) yeast extract, and 0.5% (w/v) sucrose on a New Brunswick Scientific Shaker at 27 C.Tumors were induced on potato discs by the method first described by Anand and Heberlein (1), and modified slightly in our laboratory (3). Red potatoes (Solanum tuberosum var. Red Russett) were purchased from the local market and soaked in 20%o Clorox (v/v) for 20 min. Potato discs were then obtained by placing a sterilized cork borer (20-mm diameter) through the potato and cutting 5-mm discs from the resulting plug. Five potato discs were then placed on Petri dishes containing 1.5% (w/v) agar and inoculated with 0.5 ml of bacterial suspension containing a known quantity of viable cells. The Petri dishes were placed at 27 C and exposed to 15 hr of room light and 9 hr of darkness daily. Twelve days following inoculation the tumors were counted with the aid of a dissecting scope. The tumors at this time, however, were clearly visible with the human eye. Each experimental sample consisted of three Petri dishes which contained five potato discs. Sterile techniques were employed throughout the above procedure.In order to insure that a maximum competition for attachment site...

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Section: Discussioncontrasting

confidence: 89%

Agrobacterium tumefaciens Site Attachment as a Necessary Prerequisite for Crown Gall Tumor Formation on Potato Discs

Glogowski

Galsky²

1978

Plant Physiol.

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“…It may be assumed that the initial interaction between the positively charged magainin and the bacterial surfaces is of an electrostatic nature through the multitude of negatively charged groups on the surfaces of cells, notably among them those contained in lipopolysaccharides (LPS) and teichoic acids in Gram-negative and Gram-positive bacteria, respectively [29]. Following this encounter the microbial membrane is perturbed, in a manner which is not yet clearly understood, with eventual cell death [30][31].…”

Section: Resultsmentioning

confidence: 99%

All‐D‐magainin: chirality, antimicrobial activity and proteolytic resistance

1990

FEBS Letters

271

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All‐D‐magainin‐2 was synthesized to corroborate experimentally the notion that the biological function of a surface‐active peptide stems primarily from its unique amphiphilic α ‐helical structure. Indeed, the peptide exhibited antibacterial potency nearly identical to that of the all‐L‐enantiomer. Being highly resistant to proteolysis and non‐hemolytic all‐D‐magainin might have considerable therapeutic importance.

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“…A large number of folding factors appear to act on outer membrane proteins (Missiakas and Raina 1997; Danese and Silhavy 1998), which assume ␤-barrel structures that expose the alternating hydrophobic residues of ␤-sheets at the interface with membrane lipids (Cowan et al 1992). The outer membrane is tethered to the peptidoglycan layer via murein (Braun) lipoprotein, a short helical polypeptide that is covalently linked to the peptidoglycan at the C-terminal end (Braun and Hantke 1974). The N terminus of lipoprotein is inserted into the inner leaflet of the outer membrane with its diacylglyceride decoration (Hantke and Braun 1973).…”

Section: Bacterial Surface Organellesmentioning

confidence: 99%