Background: High-pressure processing (HPP) is a commonly used technique in the food industry to inactivate pathogens, including L. monocytogenes. It has been shown that L. monocytogenes is able to recover from HPP injuries and can start to grow again during long-term cold storage. To date, the gene expression profiling of L. monocytogenes during HPP damage recovery at cooling temperature has not been studied. In order identify key genes that play a role in recovery of the damage caused by HPP treatment, we performed RNA-sequencing (RNA-seq) for two L. monocytogenes strains (barotolerant RO15 and barosensitive ScottA) at nine selected time points (up to 48 h) after treatment with two pressure levels (200 and 400 MPa).
Results: The results showed that a general stress response was activated by SigB after HPP treatment. In addition, the phosphotransferase system (PTS; mostly fructose-, mannose-, galactitol-, cellobiose-, and ascorbate-specific PTS systems), protein folding, and cobalamin biosynthesis were the most upregulated genes during HPP damage recovery. We observed that cell-division-related genes (divIC, dicIVA, ftsE, and ftsX) were downregulated. By contrast, peptidoglycan-synthesis genes (murG, murC, and pbp2A) were upregulated. This indicates that cell-wall repair occurs as a part of HPP damage recovery. We also observed that prophage genes, including anti-CRISPR genes, were induced by HPP. Interestingly, a large amount of RNA-seq data (up to 85%) was mapped to Rli47, which is a non-coding RNA that is upregulated after HPP. Thus, we predicted that Rli47 plays a role in HPP damage recovery in L. monocytogenes. Moreover, gene-deletion experiments showed that amongst peptidoglycan biosynthesis genes, pbp2A mutants are more sensitive to HPP.
Conclusions: We identified several genes and mechanisms that may play a role in recovery from HPP damage of L. monocytogenes. Our study contributes to new information on pathogen inactivation by HPP.
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http://dx.doi.org/10.1186/s12864-021-07407-6 | DOI Listing |
Front Microbiol
October 2024
State Key Laboratory of Rice Biology and Breeding, Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang Key Laboratory of Biology and Ecological Regulation of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China.
Introduction: has emerged as a significant plant pathogen affecting various crops worldwide, causing substantial economic losses. Bacteriophages and their endolysins offer promising alternatives for controlling bacterial infections, addressing the growing concerns of antibiotic resistance.
Methods: This study isolated and characterized the phage PA1 and investigated the role of PA1-LRP in directly damaging bacteria and assisting endolysin PA1-Lys in cell lysis, comparing its effect to exogenous transmembrane domains following the identification and analysis of the PA1-Lys and the PA1-LRP based on whole genome analysis of phage PA1.
Foods
September 2024
Division of Food Science and Technology, Faculty of Agro-Industry, Chiang Mai University, Chiang Mai 50100, Thailand.
Pigmented rice grass juice (RGJ) is a good source of bioactive compounds, but fresh juice has a relatively short shelf life of only 7 days at 4 °C. The objectives of this study were to determine the optimal growth stage of pigmented rice grass, investigate the optimal condition of high-pressure processing (HPP) for bacterial inactivation in inoculated RGJ using response surface methodology (RSM), and evaluate quality changes in uninoculated HPP-treated juice during storage at 4 °C compared with heat-treated (85 °C/10 min) and untreated samples. Results revealed that the optimal growth stage of rice grass was 9 days with the highest total anthocyanin content of 158.
View Article and Find Full Text PDFPolymers (Basel)
July 2024
Department of Industrial Engineering, University of Salerno, 84084 Fisciano, Italy.
Natural hydrogels based on renewable and inexpensive sources, such as starch, represent an interesting group of biopolymeric materials with a growing range of applications in the biomedical, cosmeceutical, and food sectors. Starch-based hydrogels have traditionally been produced using different processes based on chemical or physical methods. However, the long processing times, high energy consumption, and safety issues related to the synthesis of these materials, mostly causing severe environmental damage, have been identified as the main limitations for their further exploitation.
View Article and Find Full Text PDFInt J Biol Macromol
August 2024
Liaoning Key Laboratory of Food Nutrition and Health, Collaborative Innovation Center of Seafood Deep Processing, National Engineering Research Center of Seafood, School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, China. Electronic address:
Algal polysaccharides possess many biological activities and health benefits, such as antioxidant, anti-tumor, anti-coagulant, and immunomodulatory potential. Gut microbiota has emerged as one of the major contributor in mediating the health benefits of algal polysaccharides. In this study we showed that Haematococcus pluvialis polysaccharides (HPP) decreased serum transaminase levels and hepatic triglyceride content, alleviated inflammation and oxidative stress in the liver of chronic and binge ethanol diet-fed mice.
View Article and Find Full Text PDFFood Chem
July 2024
International Center of Excellence in Seafood Science and Innovation, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, Songkhla 90110, Thailand; Department of Food and Nutrition, Kyung Hee University, Seoul 02447, Republic of Korea. Electronic address:
Impact of high-pressure processing (HP-P) on hemolymph and lipid globular structures of the edible portion (EP) of blood clams (BC) was investigated. HP-P above 400 MPa decreased heme iron content, while upsurged non-heme iron content. Increasing pressure induced gaps and abnormal hemocyte cell arrangements.
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