Linked Life Data

1998695

Source:http://linkedlifedata.com/resource/pubmed/id/1998695

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1991-4-9
pubmed:abstractText
The effects of molar NaCl concentrations on the phase behaviour of the total lipid extracts and binary mixtures of the major phospholipids, namely phosphatidylethanolamine (PE) and phosphatidylglycerol (PG), isolated from the moderately halophilic eubacterium, Vibrio costicola, grown in 1 M and 3 M NaCl containing media have been studied using X-ray diffraction and freeze-fracture electron microscopy. The effect of both the PE/PG ratio and alterations in fatty acid composition were examined by using binary mixtures which mimicked the PE/PG ratio found in the native bacterial membranes. We show that the samples exhibited complex phase behaviour, including the formation of non-bilayer phases, which depend upon the salinity of both the bacterial culture medium and the suspending solution. The total lipid from bacteria cultured in 1 M NaCl-containing medium and dispersed in 1 M NaCl exhibited a mixture of L alpha and hexagonal-II phases at the optimum growth temperature of the organism (i.e., 30 degrees C), whereas the same lipid dispersed in 3 M NaCl showed only a hexagonal-II phase down to a temperature of +3 degrees C. The total lipid extracted from 3 M NaCl cultures showed only lamellar phases over the temperature range studied (+50 degrees C to -50 degrees C), but the phase transition temperatures of the various lamellar phases were generally higher when the lipid was dispersed in 3 M compared with 1 M NaCl. The phase behaviour of the binary mixtures was similar but not identical to that of the corresponding total lipid extracts and it is suggested that the minor lipid components (diphosphatidylglycerol, lysophosphatidylethanolamine and lysophosphatidylglycerol) play a part in determining the phase behaviour of the native membranes. These results show that the PE/PG ratio and fatty acid composition of the individual phospholipids, which are normally regulated by Vibrio costicola in vivo in response to culture medium salinity, are both important in maintaining a stable bilayer structure within the membrane.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
30
pubmed:volume
1061
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
235-46
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
The effect of salinity on the phase behaviour of total lipid extracts and binary mixtures of the major phospholipids isolated from a moderately halophilic eubacterium.
pubmed:affiliation
Department of Biochemistry, University of Wales, Cardiff, U.K.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't