Molecular cloning of a putative divalent-cation transporter gene as a new genetic marker for the identification of Lactobacillus brevis strains capable of growing in beer

Citation
N. Hayashi et al., Molecular cloning of a putative divalent-cation transporter gene as a new genetic marker for the identification of Lactobacillus brevis strains capable of growing in beer, APPL MICR B, 55(5), 2001, pp. 596-603
Citations number
42
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biotecnology & Applied Microbiology",Microbiology
Journal title
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
ISSN journal
0175-7598 → ACNP
Volume
55
Issue
5
Year of publication
2001
Pages
596 - 603
Database
ISI
SICI code
0175-7598(200105)55:5<596:MCOAPD>2.0.ZU;2-G
Abstract
Random amplified polymorphic DNA (RAPD) PCR analysis of Lactobacillus brevi s isolates from breweries revealed that one of the random primers could dis tinguish beer-spoilage strains of L. brevis from non-spoilage strains. The 1.1-kb DNA fragment amplified from all beer-spoilers included one open read ing frame, termed hitA (hop-inducible cation transporter), which encodes an integral membrane protein with 11 putative trans-membrane domains and a bi nding protein-dependent transport signature of a non-ATP binding membrane t ransporter common to several prokaryotic and eukaryotic transporters. The h itA polypeptide is homologous to the natural resistance-associated macropha ge protein (Nramp) family characterized as divalent-cation transport protei ns in many prokaryotic and eukaryotic organisms. Northern blot analysis ind icated that the hitA transcripts are expressed in cells cultivated in MRS b roth supplemented with hop bitter compounds, which act as mobile-carrier io nophores, dissipating the trans-membrane pH gradient in bacteria sensitive to the hop bitter compounds by exchanging Hf for cellular divalent cations such as Mn2+. This suggests that the hitA gene products may play an importa nt role in making the bacteria resistant to hop bitter compounds in beer by transporting metal ions such as Mn2+ into cells that no longer maintain th e proton gradient.