Development of a rapid induction assay for quantifying lysine in foods /
L-lysine is one of the ten essential amino acids and is usually used as an indicator of the potential biological value of food protein. Industrial food processing treatments may involve the use of heat, oxidizing agents, organic solvents, alkalis and acids and could substantially decrease the nutrit...
| Main Author: | |
|---|---|
| Format: | Thesis Book |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
2002.
|
| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=765106341&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | L-lysine is one of the ten essential amino acids and is usually used as an indicator of the potential biological value of food protein. Industrial food processing treatments may involve the use of heat, oxidizing agents, organic solvents, alkalis and acids and could substantially decrease the nutritional value of lysine via formation of Maillard compounds, conversion to the D-isomer, and cross-linked peptides. Microbiological methods involving growth of E. coli auxotrophs have been used for biological assays of amino acids from a variety of biological materials and have been used to determine amino acid availability in acid hydrolysate protein quality determinations. An alternative rapid microbiological assay is proposed, in which a strain of E. coli with an inducible lysine specific fluorescent fusion (as a reporter gene) will be used for the determination of lysine in foods. Coupling of green fluorescent protein gene (gfp), with a lysine-dependent inducible promoter region, will result in a fluorescent response directly related to the presence of lysine in test media. A lysine inducible promoter from the cadBA operon was isolated by PCR from E. coli K-12 genomic DNA, digested with appropriate restriction enzymes and cloned in a promoterless mini-Tn5gfp mutagenesis system (Mathisse et al., 1996). pMini Tn-5PcadA::gfp was used to mutagenize E. coli K-12 and clones with a lysine-inducible fluorescent phenotype were selected. Once a potential candidate for the test strain was selected, the inducible assay was used to correlate the levels of lysine with a cellular response (measured as emission of light) due to the expression of genes present in the recombinant cells. |
|---|---|
| Item Description: | Vita. "Major Subject: Poultry Science". |
| Physical Description: | xiv, 142 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 126-141). |