Linked Life Data

11207717

Source:http://linkedlifedata.com/resource/pubmed/id/11207717

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2001-3-27
pubmed:abstractText
The multicomponent glucose transport system of Escherichia coli was used to study the polygenic basis of increased fitness in prolonged nutrient-limited, continuous cultures. After 280 generations of glucose-limited growth, nearly all bacteria in four independent chemostat populations exhibited increased glucose transport and contained multiple, stable mutations. Fitter bacteria increased outer membrane permeability for glucose through overexpression of the LamB glycoporin. Three classes of mutation influenced LamB levels as well as regulation of other mal genes. Low-level mal/lamB constitutivity resulted from mlc mutations acquired in all populations as well as changes at another uncharacterized locus. Larger increases in transporter content resulted from widespread acquisition of a regulatory malT-con mutation in fit isolates. The malT mutations sequenced from 67 adapted isolates were all single base substitutions resulting in amino acid replacements in the N-terminal third of the MalT activator protein. Analysis of malT-con sequences revealed a mutational spectrum distinct from that found in plate-selected malT mutants, suggesting that mutational pathways were affected by environmental factors. A second major finding was the remarkable allele diversity in malT within a population derived from a single clone, with at least 11 different alleles co-existing in a population. The multiplicity of alleles (as well as those found in adaptive mgl changes in the accompanying study) suggest that the periodic selection events observed previously in such populations are not a major factor in reducing genetic diversity. A simple model is presented for the generation of genetic heterogeneity in bacterial populations undergoing polygenic selection.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
1462-2912
pubmed:author
pubmed:issnType
Print
pubmed:volume
1
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
45-52
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed-meshheading:11207717-Adaptation, Physiological, pubmed-meshheading:11207717-Alleles, pubmed-meshheading:11207717-Amino Acid Substitution, pubmed-meshheading:11207717-Bacterial Outer Membrane Proteins, pubmed-meshheading:11207717-Bacterial Proteins, pubmed-meshheading:11207717-Biological Evolution, pubmed-meshheading:11207717-Biological Transport, Active, pubmed-meshheading:11207717-Culture Media, pubmed-meshheading:11207717-DNA-Binding Proteins, pubmed-meshheading:11207717-Escherichia coli, pubmed-meshheading:11207717-Escherichia coli Proteins, pubmed-meshheading:11207717-Genes, Bacterial, pubmed-meshheading:11207717-Genetic Variation, pubmed-meshheading:11207717-Glucose, pubmed-meshheading:11207717-Mutation, pubmed-meshheading:11207717-Porins, pubmed-meshheading:11207717-Receptors, Virus, pubmed-meshheading:11207717-Selection, Genetic, pubmed-meshheading:11207717-Transcription Factors
pubmed:year
1999
pubmed:articleTitle
The generation of multiple co-existing mal-regulatory mutations through polygenic evolution in glucose-limited populations of Escherichia coli.
pubmed:affiliation
Department of Microbiology G08, University of Sydney, NSW, Australia.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't