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Development of a Chromosome‐Plasmid Balanced Lethal System for Lactobacillus acidophilus with thyA Gene as Selective Marker
Author(s) -
Fu Xiaoli,
Xu Jianguo
Publication year - 2000
Publication title -
microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0385-5600
DOI - 10.1111/j.1348-0421.2000.tb02533.x
Subject(s) - plasmid , biology , shuttle vector , puc19 , lactobacillus acidophilus , genetics , replicon , multiple cloning site , restriction site , lethal allele , lactobacillus casei , microbiology and biotechnology , t dna binary system , gene , restriction enzyme , vector (molecular biology) , recombinant dna , bacteria , probiotic
A chromosome‐plasmid balanced lethal gene delivery system for Lactobacillus acidophilus based on the thyA gene was developed. The selected L. acidophilus DOM La strain carries a mutated thyA gene and has an obligate requirement for thymidine. This strain can be used as a host for the constructed shuttle vector pFXL03, lacking antibiotic‐resistant markers but having the wild‐type thyA gene from L. casei which complements the thyA chromosomal mutation. The vector also contains the replicon region from plasmid pUC19 and that of the Lactococcus plasmid pWV01, which allows the transfer between Escherichia coli, L. casei and L. acidophilus . Eight unique restriction sites (i.e., Pst I, Hin dIII, Sph I, Saf I, Acc I, Xba I, Kpn I and Sac I) are available for cloning. After 40‐time transfers in modified MRS medium, no plasmid loss was observed. The vector pFXL03 is potentially useful as a food‐grade vaccine delivery system for L. acidophilus .