Document Detail

Proteinase production in Pseudomonas fluorescens ON2 is affected by carbon sources and allows surface-attached but not planktonic cells to utilize protein for growth in lake water.
MedLine Citation:
PMID:  22224410     Owner:  NLM     Status:  Publisher    
Proteins may be an important carbon and nitrogen source to bacteria in aquatic habitats, yet knowledge on the actual utilization of this substrate by proteolytic bacteria is scarce. In the present study, Pseudomonas fluorescens ON2 produced an alkaline proteinase (AprX) during growth and there was no evidence for cell density-regulated or starvation-induced proteinase production. Proteinase was produced in the absence of an organic nitrogen source, and citrate had a negative while glucose had a positive effect on the production. Hence P. fluorescens ON2 seems to exploit protein sources by expressing the proteinase during growth unless a preferred carbon source like citrate is present. Lake water model systems were subsequently used to investigate the ability of proteolytic versus non-proteolytic ON2 strains to utilize protein for growth at moderate cell densities. Only cells forming surface-attached micro-colonies were able to utilize this resource, while planktonic cells were not. Our experiments are the first to experimentally support models predicting that production of extra-cellular enzymes in dilute environments may be a waste of resources, whereas it represents a favorable feeding strategy in organic matrices like detritus, micro-colonies or biofilm.
Mette H Nicolaisen; Jakob Worm; Niels O G Jørgensen; Mathias Middelboe; Ole Nybroe
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-1-6
Journal Detail:
Title:  FEMS microbiology ecology     Volume:  -     ISSN:  1574-6941     ISO Abbreviation:  -     Publication Date:  2012 Jan 
Date Detail:
Created Date:  2012-1-9     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8901229     Medline TA:  FEMS Microbiol Ecol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
© 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.
Genetics and Microbiology Section, Department of Agriculture and Ecology, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark.
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