title: Sodium chloride-induced filamentation and alternative gene expression of fts, murZ, and gnd in Listeria monocytogenes 08-5923 on vacuum-packaged ham.
abstract: The aim of this study was to examine the filament formation and differential gene expression of Listeria monocytogenes 08-5923 grown on refrigerated vacuum-packaged ham products with various NaCl concentrations. Filament formation of L. monocytogenes was observed on ham products with 1.35% and 2.35% NaCl, which was monitored using flow cytometry by measuring forward light scatter. Quantitative real-time PCR was used to study the differential expression of genes in filamented cells of L. monocytogenes grown on hams following 2 or 3 months of storage at 4 °C. The genes involved in cell division (ftsX/lmo2506), cell wall synthesis (murZ/lmo2552), and NADPH production (gnd/lmo1376) were significantly downregulated in filamented cells of L. monocytogenes grown on ham with 2.35% NaCl stored at 4 °C. To our knowledge, this study reports the first evidence of filament formation of Listeria grown on meat products, which could impact the food safety risk and tolerance levels of L. monocytogenes set by regulatory agencies.
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada.
authors.forename: Xiaoji
authors.initials: X
authors.lastname: Liu
authors.forename: Petr
authors.initials: P
authors.lastname: Miller
authors.forename: Urmila
authors.initials: U
authors.lastname: Basu
authors.forename: Lynn M
authors.initials: LM
authors.lastname: McMullen
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D002455:Cell Division / Q000187:drug effects* / Q000528:radiation effects; D005434:Flow Cytometry; D015870:Gene Expression / Q000187:drug effects* / Q000528:radiation effects; D020869:Gene Expression Profiling; D008089:Listeria monocytogenes / Q000235:genetics* / Q000254:growth & development*; D008461:Meat Products / Q000382:microbiology*; D060888:Real-Time Polymerase Chain Reaction; D012034:Refrigeration; D012965:Sodium Chloride / Q000378:metabolism*; D014618:Vacuum
chemical_list: D001426:Bacterial Proteins; D012965:Sodium Chloride
keywords: Listeria; filamentation; flow cytometry; ham; qRT-PCR