Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1995-6-1
pubmed:abstractText
The thiol-activated toxin pneumolysin is a known pneumococcal virulence factor, with both cytotoxic (hemolytic) and complement activation properties. Copies of the pneumolysin gene carrying defined point mutations affecting either or both of these properties were introduced into the chromosome of Streptococcus pneumoniae D39 by insertion-duplication mutagenesis. The virulences of these otherwise isogenic strains were then compared. There was no significant difference in either the median survival time or overall survival rate between mice challenged with D39 derivatives producing the wild-type toxin and those expressing a pneumolysin gene with an Asp-385-->Asn mutation, which abolishes the complement activation property. However, mice challenged with strains carrying either His-367-->Arg or Trp-433-->Phe plus Cys-428-->Gly mutations, which reduce hemolytic activity to approximately 0.02 and 0.0001% of the wild-type level, respectively, had significantly greater median survival times and overall survival rates than mice challenged with D39 derivatives expressing a wild-type pneumolysin gene. No additional reduction in virulence was observed when mice were challenged with a D39 derivative carrying Trp-433-->Phe, Cys-428-->Gly, and Asp-385-->Asn, rather than Trp-433-->Phe and Cys-428-->Gly, mutations in the pneumolysin gene. Thus, it appears that in the intraperitoneal challenge model, the contribution of pneumolysin to virulence is largely attributable to its hemolytic (cytotoxic) properties rather than to its capacity to activate complement. Interestingly, however, the amount of pneumolysin required for full virulence may be very small, as D39 derivatives carrying the Trp-433-->Phe mutation (which reduces hemolytic activity to 0.1% of the wild-type level) had intermediate virulence.
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-1195397, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-1350046, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-1563759, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-1766369, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-1779752, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-1834101, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-2050399, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-2731981, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-2731982, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-2744861, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-2854594, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-3019892, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-3782044, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-3804376, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-388439, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-4150368, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-5432063, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-6312838, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-6319229, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-6389352, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-6698602, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-6840851, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-6885160, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-7025155, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-7358434, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-7903033, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-7960154, http://linkedlifedata.com/resource/pubmed/commentcorrection/7729909-8454338
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0019-9567
pubmed:author
pubmed:issnType
Print
pubmed:volume
63
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1969-74
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Effect of defined point mutations in the pneumolysin gene on the virulence of Streptococcus pneumoniae.
pubmed:affiliation
Department of Microbiology, Women's and Children's Hospital, North Adelaide, South Australia.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't