The production of lipase and protease from psychrotrophic strains of Pseudomonas fluorescens may result in spoilage of dairy products. The lipase (lipA) and alkaline metalloprotease (aprX) genes of P. fluorescens B52 are regulated by temperature and are located at opposite ends of an operon which contains eight genes and spans 14 kb. In this report, we show that lipase activity in the supernatant of cultures of P. fluorescens strain B52 is also regulated by the homologue of the Escherichia coli EnvZ-OmpR two-component regulatory system. Differences in the regulation of lipase and protease may be related to the proximal and distal locations of aprX and lipA within the operon.
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http://dx.doi.org/10.1016/j.femsle.2004.10.027 | DOI Listing |
Microbiology (Reading)
January 2025
Department of Microbiology and Molecular Genetics, Larner College of Medicine, University of Vermont, Burlington, USA.
Sphingoid bases, including sphingosine, are important components of the antimicrobial barrier at epithelial surfaces where they can cause growth inhibition and killing of susceptible bacteria. is a common opportunistic pathogen that is less susceptible to sphingosine than many Gram-negative bacteria. Here, we determined that the deletion of the operon reduced growth in the presence of sphingosine.
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January 2025
College of Food Science and Technology, Huazhong Agricultural University, National R & D Branch Center for Conventional Freshwater Fish Processing, Wuhan, Hubei Province 430070, PR China. Electronic address:
Photodynamic inactivation (PDI) has emerged as a novel non-thermal process technology for inactivating microorganisms due to its low cost, safety, and efficiency. This study aimed to investigate the antimicrobial effect of VK-mediated PDI against Pseudomonas fluorescens (P. fluorescens) and to assess its impact on the quality of the blunt bream contaminated with P.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
University of Pittsburgh School of Medicine, Structural Biology, 3501 5th Ave., Biomedical Science Tower 3, Room 2044, 15261, Pittsburgh, UNITED STATES OF AMERICA.
Bacterial biofilms are major contributors to persistent infections and antimicrobial resistance, posing significant challenges to treatment. However, obtaining high-resolution structural information on native bacterial biofilms has remained elusive due to the methodological limitations associated with analyzing complex biological samples. Solid-state NMR (ssNMR) has shown promise in this regard, but its conventional application is hindered by sensitivity constraints for unlabeled native samples .
View Article and Find Full Text PDFMicroorganisms
December 2024
Applied Biotechnology Department, University of Technology and Applied Sciences, P.O. Box 411, Sur 411, Oman.
Determining the microbial quality and safety of meat is crucial because of its high potential to harbor pathogens. To address the critical knowledge gap and shed light on potential contamination risk in the meat supply chain, this study aimed to assess the underexplored microbial quality and safety of marketed beef meat in Oman. Thirty-three beef meat samples from six hypermarkets were analyzed for Aerobic Plate Count (APC), Psychrotrophic Bacteria Count (PBC), and coliform and counts.
View Article and Find Full Text PDFMicroorganisms
December 2024
Departamento de Ciências Farmacêuticas, Faculdade de Farmácia, Universidade Federal de Juiz de Fora (UFJF), Juiz de Fora 36036-900, MG, Brazil.
are significant spoilage bacteria in raw milk and dairy products, primarily due to their ability to form biofilms and resist disinfection. This study explored the effects of the phage combined with sodium hypochlorite in reducing biofilms on stainless steel at various temperatures and ages. Biofilms were formed using UFV 041 in UHT milk, incubated at 4 °C and 30 °C for 2 and 7 days.
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