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GENERATION OF BIOLUMINESCENT MORGANELLA MORGANII AND ITS POTENTIAL USAGE IN DETERMINATION OF GROWTH LIMITS AND HISTAMINE PRODUCTION
Author(s) -
ZAREI MEHDI,
HOSSEINI ARSALAN,
SHEKARFOROUSH S. SHAHRAM
Publication year - 2009
Publication title -
journal of food safety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 43
eISSN - 1745-4565
pISSN - 0149-6085
DOI - 10.1111/j.1745-4565.2009.00150.x
Subject(s) - morganella morganii , bioluminescence , bioreporter , biology , plasmid , bacterial growth , histamine , exponential growth , microbiology and biotechnology , escherichia coli , biochemistry , enterobacteriaceae , bacteria , gene expression , reporter gene , gene , mathematics , genetics , mathematical analysis , endocrinology
A mini‐Tn5 promoter probe carrying the intact lux operon of Photorhabdus luminescens (pUT mini‐Tn5 luxCDABE ) which allowed measurement of light output without the addition of exogenous substrate was constructed. It was used to create a pool of chromosomally lux ‐marked strains of Morganella morganii. Also plasmid‐mediated expression of bioluminescence in M. morganii was assessed using plasmid pT7‐3 luxCDABE. No significant differences in growth and histamine formation characteristics of the lux ‐marked strains and wild type M. morganii strain were observed. Luminescent strain of M. morganii was used in experiments in which the correlation between light output, viable cell count and histamine formation was assessed. During the exponential growth phase, a positive linear correlation was observed between these three parameters in trypticase soy broth‐histidine medium at 37C. It was demonstrated that expression of bioluminescence had not had a significant effect upon both growth rate and histamine production. Thus, the measurement of bioluminescence was found to be a simple, fast and reliable method for determination of viable cell count and histamine content.PRACTICAL APPLICATIONS Constructing predictive models in microbiology requires a large number of data on desired factors. Commonly used traditional methods of counting viable cells and measuring histamine, e.g., to model the growth limits of M. morganii as a function of different intrinsic and extrinsic factors, are time consuming and laborious, and require a lot of laboratory space and materials. According to the results of this research, measurement of bioluminescence is a simple, fast and reliable method for the determination of viable cell count and histamine content during the exponential growth phase. Thus, it can be used as a labor‐ and material‐saving selective data capture method for constructing predictive models in many different areas.