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United States Department of Agriculture

Agricultural Research Service

Title: Biophysical Properties of Lipids from Symbotic Bacterial Associates of Entomopathogenic Nematodes.

Authors
item Fodor, Elfridia - HUNGARIAN ACADEMY OF SCI.
item Szallas, Emillia - EOTVOS LORAND UNIV.
item Kiss, Zsuzsanna - EOTVOS LORAND UNIV.
item Fodor, Andras - EOTVOS LORAND UNIV.
item CHITWOOD, DAVID
item Farkas, Tibor - HUNGARIAN ACADEMY OF SCI.

Submitted to: American Society of Parasitologists
Publication Type: Abstract Only
Publication Acceptance Date: June 15, 1996
Publication Date: N/A

Technical Abstract: The entomopathogenic nematodes Heterorhabditis spp. and Steinernema carpocapsae contain the insect-killing bacterial symbionts Photorhabdus luminescens and Xenorhabdus nematophilus, respectively. The two bacterial species exist in culture as primary and secondary phase variants, which differ in secretion of metabolic end products and in survival within the nematode digestive system. To determine if these differences result from membrane physical properties, primary and secondary phase variants of P. luminescens Hm and X. nematophilus N2-4 were grown at 18 C and 28 C from 24 to 96 hours. At each temperature and culture period, vesicles were prepared from total lipids extracted from the bacteria. Vesicle membrane fluidity was determined with an electron spin resonance procedure utilizing 5-doxyl-stearic acid as a probe. Vesicles from primary and secondary cultures of both bacterial species grown at 18 C were more ordered than those grown at 28 C. Vesicles from primary cultures of P. luminescens were substantially more ordered than those from secondary cultures. In X. nematophilus, this difference was less conspicuous. At both culture temperatures, membranes from primary cultures of P. luminescens were more ordered than membranes from X. nematophilus. The results reflect interesting biophysical differences between the membranes of the two species.

Last Modified: 8/19/2014
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