Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
2003-5-19
pubmed:abstractText
To evaluate the contribution of intracellular peptidases to the growth of the 14-amino-acid (aa) auxotroph Lactobacillus helveticus CNRZ32, single- and multiple-peptidase-deletion mutants were constructed. Two broad-specificity aminopeptidases (PepC and PepN) and X-prolyl dipeptidyl aminopeptidase (PepX) were inactivated through successive cycles of chromosomal gene replacement mutagenesis. The inactivation of all three peptidases in JLS247 ((Delta)pepC (Delta)pepN (Delta)pepX) did not affect the growth rate in amino acid-defined medium. However, the peptidase mutants generally had decreased specific growth rates when acquisition of amino acids required hydrolysis of the proteins in milk, the most significant result being a 73% increase in generation time for JLS247. The growth rate deficiencies in milk were overcome by amino acid supplements with some specificity to each of the peptidase mutants. For example, milk supplementation with Pro resulted in the most significant growth rate increase for (Delta)pepX strains and a 7-aa supplement (Asn, Cys, Ile, Pro, Ser, Thr, and Val) resulted in a JLS247 growth rate indistinguishable from that of the wild type. Our results show that characterization of the activities of the broad-specificity aminopeptidases had little predictive value regarding the amino acid supplements found to enhance the milk growth rates of the peptidase mutant strains. These results represent the first determination of the physiological roles with respect to specific amino acid requirements for peptidase mutants grown in milk.
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-10075426, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-10406960, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-10532381, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-11371525, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-11401725, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-2118509, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-3116269, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-3311881, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-3389511, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-3843705, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-3883896, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-3912411, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-7003163, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-7039409, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-7487034, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-7698673, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-7768792, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-7925424, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-8012576, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-8104928, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-8117086, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-8299952, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-8398214, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-8631666, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-8867635, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-8879407, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-9004508, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-9254694, http://linkedlifedata.com/resource/pubmed/commentcorrection/12754227-9281817
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-9193
pubmed:author
pubmed:issnType
Print
pubmed:volume
185
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3297-306
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Impaired growth rates in milk of Lactobacillus helveticus peptidase mutants can be overcome by use of amino acid supplements.
pubmed:affiliation
Department of Bacteriology, University of Wisconsin-Madison, 53706, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't