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Li H, Lv Y, Zhang Y, Wang X, Yang X, Qu J. Fermentation properties and functional stability of dough starter Jiaozi and Laomian after frozen storage. Front Microbiol 2024; 15:1379484. [PMID: 38680920 PMCID: PMC11046002 DOI: 10.3389/fmicb.2024.1379484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 03/25/2024] [Indexed: 05/01/2024] Open
Abstract
Purpose This study aims to investigate the effects of frozen storage on the stability of traditional dough starters in China. Methods The microbial community structure and abundance of related metabolic genes in different fermented sourdough prepared by Jiaozi (JZ) and Laomian (LM) starters before and after frozen storage at -20°C for half a year were analyzed using the shotgun metagenomic sequencing method, and differences in characteristics of texture in steamed bread were also compared by formal methods. Results The fermentation ability (FA) and metabolic activities of yeast in the JZH sourdough (started by JZ which was stored at -20°C for half a year) were better than those of LMH sourdough (started by LM which was stored at -20°C for half a year). The dominant genera of Acetobacter were found to be increased in the JZH0 sourdough (started by JZH and fermented for 0 h) and those of Lactobacillus were found to be decreased. Lactobacillus (98.72%), Pediococcus (0.37%), Saccharomyces (0.27%), and Acetobacter (0.01%), were dominant in sourdough LMH0 (started by LMH and fermented for 0 h). The abundances of "oxidative phosphorylation-related enzymes" and the "biosynthesis of glutamate"-related enzymes and genes related to "biosynthesis of glutamate" and "unsaturated fatty acid" were higher in JZH0 than in the JZ0 sourdough (started by JZ without being frozen and fermented for 0 h). The good FA of yeast, the acid production capacity of bacteria in the sourdough, and the quality of the JZH steamed bread (made by the JZH starter) indicated the better freezing tolerance of the microorganisms in JZ than in LM. Conclusion The conclusion of this study suggests the better application potential of the JZ as the fermentation starter in actual production.
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Affiliation(s)
- Haifeng Li
- School of Biological Engineering, Henan University of Technology, Zhengzhou, China
| | - Yulan Lv
- School of Biological Engineering, Henan University of Technology, Zhengzhou, China
| | - Yingmiao Zhang
- School of Biological Engineering, Henan University of Technology, Zhengzhou, China
| | - Xifeng Wang
- School of Biological Engineering, Henan University of Technology, Zhengzhou, China
| | - Xiaohong Yang
- College of Basic Medicine, Hebei Medical University, Shijiazhuang, China
| | - Jianhang Qu
- School of Biological Engineering, Henan University of Technology, Zhengzhou, China
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Shao L, Sun Y, Zou B, Zhao Y, Li X, Dai R. Sublethally injured microorganisms in food processing and preservation: Quantification, formation, detection, resuscitation and adaption. Food Res Int 2023; 165:112536. [PMID: 36869540 DOI: 10.1016/j.foodres.2023.112536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 01/14/2023] [Accepted: 01/21/2023] [Indexed: 01/29/2023]
Abstract
Sublethally injured state has been recognized as a survival strategy for microorganisms suffering from stressful environments. Injured cells fail to grow on selective media but can normally grow on nonselective media. Numerous microorganism species can form sublethal injury in various food matrices during processing and preservation with different techniques. Injury rate was commonly used to evaluate sublethal injury, but mathematical models for the quantification and interpretation of sublethally injured microbial cells still require further study. Injured cells can repair themselves and regain viability on selective media under favorable conditions when stress is removed. Conventional culture methods might underestimate microbial counts or present a false negative result due to the presence of injured cells. Although the structural and functional components may be affected, the injured cells pose a great threat to food safety. This work comprehensively reviewed the quantification, formation, detection, resuscitation and adaption of sublethally injured microbial cells. Food processing techniques, microbial species, strains and food matrix all significantly affect the formation of sublethally injured cells. Culture-based methods, molecular biological methods, fluorescent staining and infrared spectroscopy have been developed to detect the injured cells. Cell membrane is often repaired first during resuscitation of injured cells, meanwhile, temperature, pH, media and additives remarkably influence the resuscitation. The adaption of injured cells negatively affects the microbial inactivation during food processing.
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Affiliation(s)
- Lele Shao
- Beijing Higher Institution Engineering Research Center of Animal Product, College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Qinghua East Road, Haidian District, Beijing 100083, PR China
| | - Yingying Sun
- Beijing Higher Institution Engineering Research Center of Animal Product, College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Qinghua East Road, Haidian District, Beijing 100083, PR China
| | - Bo Zou
- Beijing Higher Institution Engineering Research Center of Animal Product, College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Qinghua East Road, Haidian District, Beijing 100083, PR China
| | - Yijie Zhao
- Beijing Higher Institution Engineering Research Center of Animal Product, College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Qinghua East Road, Haidian District, Beijing 100083, PR China
| | - Xingmin Li
- Beijing Higher Institution Engineering Research Center of Animal Product, College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Qinghua East Road, Haidian District, Beijing 100083, PR China
| | - Ruitong Dai
- Beijing Higher Institution Engineering Research Center of Animal Product, College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Qinghua East Road, Haidian District, Beijing 100083, PR China.
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TMT proteomic analysis for molecular mechanism of Staphylococcus aureus in response to freezing stress. Appl Microbiol Biotechnol 2022; 106:3139-3152. [PMID: 35460349 DOI: 10.1007/s00253-022-11927-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 04/07/2022] [Accepted: 04/11/2022] [Indexed: 11/02/2022]
Abstract
The foodborne pathogen Staphylococcus aureus continues to challenge the food industry due to the pathogenicity and tolerance of the bacterium. As a common storage condition for frozen food during transportation, distribution, and storage, freezing does not seem to be entirely safe due to the cold tolerance of S. aureus. In addition, our study indicated that the biofilm formation ability of S. aureus was significantly increased in response to freezing stress. To explore the molecular mechanism regulating the response to freezing stress, the proteomics signature of S. aureus after freezing stress based on tandem mass tag (TMT) labeling and liquid chromatography tandem mass spectrometry (LC-MS/MS) was analyzed. Gene Ontology and pathway analysis revealed that ribosome function, metabolism, RNA repair, and stress response proteins were differentially regulated (P < 0.05). Furthermore, transpeptidase sortase A, biofilm operon icaADBC HTH-type negative transcriptional regulator IcaR, and HTH-type transcriptional regulator MgrA were involved in the modulation of increased biofilm formation in response to freezing stress (P < 0.05). Moreover, significant lysine acetylation and malonylation signals in the S. aureus response to freezing stress were observed. Collectively, the current work provides additional insight for comprehending the molecular mechanism of S. aureus in response to freezing stress and presents potential targets for developing strategies to control S. aureus. KEY POINTS: • TMT proteomic analysis was first used on S. aureus in response to freezing stress. • Ribosome-, metabolism-, and biofilm-related proteins change after freezing stress. • Increased biofilm formation in S. aureus responded to freezing stress.
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Comparative Transcriptomic Analysis of Staphylococcus aureus Reveals the Genes Involved in Survival at Low Temperature. Foods 2022; 11:foods11070996. [PMID: 35407083 PMCID: PMC8997709 DOI: 10.3390/foods11070996] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/23/2022] [Accepted: 03/26/2022] [Indexed: 02/05/2023] Open
Abstract
In food processing, the temperature is usually reduced to limit bacterial reproduction and maintain food safety. However, Staphylococcus aureus can adapt to low temperatures by controlling gene expression and protein activity, although its survival strategies normally vary between different strains. The present study investigated the molecular mechanisms of S. aureus with different survival strategies in response to low temperatures (4 °C). The survival curve showed that strain BA-26 was inactivated by 6.0 logCFU/mL after 4 weeks of low-temperature treatment, while strain BB-11 only decreased by 1.8 logCFU/mL. Intracellular nucleic acid leakage, transmission electron microscopy, and confocal laser scanning microscopy analyses revealed better cell membrane integrity of strain BB-11 than that of strain BA-26 after low-temperature treatment. Regarding oxidative stress, the superoxide dismutase activity and the reduced glutathione content in BB-11 were higher than those in BA-26; thus, BB-11 contained less malondialdehyde than BA-26. RNA-seq showed a significantly upregulated expression of the fatty acid biosynthesis in membrane gene (fabG) in BB-11 compared with BA-26 because of the damaged cell membrane. Then, catalase (katA), reduced glutathione (grxC), and peroxidase (ahpC) were found to be significantly upregulated in BB-11, leading to an increase in the oxidative stress response, but BA-26-related genes were downregulated. NADH dehydrogenase (nadE) and α-glucosidase (malA) were upregulated in the cold-tolerant strain BB-11 but were downregulated in the cold-sensitive strain BA-26, suggesting that energy metabolism might play a role in S. aureus under low-temperature stress. Furthermore, defense mechanisms, such as those involving asp23, greA, and yafY, played a pivotal role in the response of BB-11 to stress. The study provided a new perspective for understanding the survival mechanism of S. aureus at low temperatures.
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Xia X, Liu J, Huang L, Zhang X, Deng Y, Li F, Liu Z, Huang R. Molecular Details of Actinomycin D-Treated MRSA Revealed via High-Dimensional Data. Mar Drugs 2022; 20:md20020114. [PMID: 35200643 PMCID: PMC8878686 DOI: 10.3390/md20020114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 01/18/2022] [Accepted: 01/27/2022] [Indexed: 02/04/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is highly concerning as a principal infection pathogen. The investigation of higher effective natural anti-MRSA agents from marine Streptomyces parvulus has led to the isolation of actinomycin D, that showed potential anti-MRSA activity with MIC and MBC values of 1 and 8 μg/mL, respectively. Proteomics-metabolomics analysis further demonstrated a total of 261 differential proteins and 144 differential metabolites induced by actinomycin D in MRSA, and the co-mapped correlation network of omics, indicated that actinomycin D induced the metabolism pathway of producing the antibiotic sensitivity in MRSA. Furthermore, the mRNA expression levels of the genes acnA, ebpS, clfA, icd, and gpmA related to the key differential proteins were down-regulated measured by qRT-PCR. Molecular docking predicted that actinomycin D was bound to the targets of the two key differential proteins AcnA and Icd by hydrogen bonds and interacted with multiple amino acid residues of the proteins. Thus, these findings will provide a basic understanding to further investigation of actinomycin D as a potential anti-MRSA agent.
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Affiliation(s)
- Xuewei Xia
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China; (X.X.); (L.H.); (Y.D.); (F.L.); (Z.L.)
| | - Jun Liu
- Laboratory of Pathogenic Biology, Guangdong Medical University, Zhanjiang 524023, China;
| | - Li Huang
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China; (X.X.); (L.H.); (Y.D.); (F.L.); (Z.L.)
| | - Xiaoyong Zhang
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China;
| | - Yunqin Deng
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China; (X.X.); (L.H.); (Y.D.); (F.L.); (Z.L.)
| | - Fengming Li
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China; (X.X.); (L.H.); (Y.D.); (F.L.); (Z.L.)
| | - Zhiyuan Liu
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China; (X.X.); (L.H.); (Y.D.); (F.L.); (Z.L.)
| | - Riming Huang
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China; (X.X.); (L.H.); (Y.D.); (F.L.); (Z.L.)
- Correspondence:
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López GD, Suesca E, Álvarez-Rivera G, Rosato AE, Ibáñez E, Cifuentes A, Leidy C, Carazzone C. Carotenogenesis of Staphylococcus aureus: New insights and impact on membrane biophysical properties. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:158941. [PMID: 33862238 DOI: 10.1016/j.bbalip.2021.158941] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 03/18/2021] [Accepted: 03/31/2021] [Indexed: 11/30/2022]
Abstract
Staphyloxanthin (STX) is a saccharolipid derived from a carotenoid in Staphylococcus aureus involved in oxidative-stress tolerance and antimicrobial peptide resistance. STX influences the biophysical properties of the bacterial membrane and has been associated to the formation of lipid domains in the regulation of methicillin-resistance. In this work, a targeted metabolomics and biophysical characterization study was carried out to investigate the biosynthetic pathways of carotenoids, and their impact on the membrane biophysical properties. Five different S. aureus strains were investigated, including three wild-type strains containing the crtM gene related to STX biosynthesis, a crtM-deletion mutant, and a crtMN plasmid-complemented variant. LC-DAD-MS/MS analysis of extracts allowed the identification of 34 metabolites related to carotenogenesis in S. aureus at different growth phases (8, 24 and 48 h), showing the progression of these metabolites as the bacteria advances into the stationary phase. For the first time, 22 members of a large family of carotenoids were identified, including STX and STX-homologues, as well as Dehydro-STX and Dehydro-STX-homologues. Moreover, thermotropic behavior of the CH2 stretch of lipid acyl chains in live cells by FTIR, show that the presence of STX increases acyl chain order at the bacterial growth temperature. Indeed, the cooperative melting event of the bacterial membrane, which occurs around 15 °C in the native strains, shifts with increased carotenoid content. These results show the diversity biosynthetic of carotenoids in S. aureus, and their influence on membrane biophysical properties.
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Affiliation(s)
- Gerson-Dirceu López
- Laboratory of Advanced Analytical Techniques in Natural Products (LATNAP), Chemistry Department, Universidad de los Andes, Bogotá D.C., Colombia; Laboratory of Biophysics, Physics Department, Universidad de los Andes, Bogotá D.C., Colombia; Laboratory of Foodomics, Institute of Food Science Research, CIAL, CSIC, Madrid, Spain
| | - Elizabeth Suesca
- Laboratory of Biophysics, Physics Department, Universidad de los Andes, Bogotá D.C., Colombia
| | | | - Adriana E Rosato
- Molecular Microbiology Diagnostics-Research, Riverside University Health System, Professor Loma Linda University, Moreno Valley, CA, USA
| | - Elena Ibáñez
- Laboratory of Foodomics, Institute of Food Science Research, CIAL, CSIC, Madrid, Spain
| | - Alejandro Cifuentes
- Laboratory of Foodomics, Institute of Food Science Research, CIAL, CSIC, Madrid, Spain
| | - Chad Leidy
- Laboratory of Biophysics, Physics Department, Universidad de los Andes, Bogotá D.C., Colombia.
| | - Chiara Carazzone
- Laboratory of Advanced Analytical Techniques in Natural Products (LATNAP), Chemistry Department, Universidad de los Andes, Bogotá D.C., Colombia.
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7
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Panisello Yagüe D, Mihaljevic J, Mbegbu M, Wood CV, Hepp C, Kyman S, Hornstra H, Trotter R, Cope E, Pearson T. Survival of Staphylococcus aureus on sampling swabs stored at different temperatures. J Appl Microbiol 2021; 131:1030-1038. [PMID: 33544965 PMCID: PMC8339145 DOI: 10.1111/jam.15023] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 01/26/2021] [Accepted: 02/01/2021] [Indexed: 02/04/2023]
Abstract
Aims To understand the impact of storage temperature on recovery of Staphylococcus aureus on sampling swabs. Staphylococcus aureus is a common cause of skin and soft tissue infections, but also causes a variety of life‐threatening diseases. With a large pool of asymptomatic carriers and transmission that can occur even through indirect contact, mitigation efforts have had limited success. Swab sampling, followed by culturing, is a cornerstone of epidemiological studies, however, S. aureus viability on swabs stored at different temperatures has not been characterized. Methods and Results We determined survival rates on swabs stored at five different temperatures. Samples stored at −70°C had no decay over time while samples stored at higher temperatures showed an exponential decay in viability. Mortality rates were greatest for swabs stored at 37°C. Survival at intermediate temperatures (−20 to 20·5°C) did not differ significantly, however, we observed more variation at higher temperatures. Conclusions To maximize recovery of S. aureus cells, samples should be stored at −70°C or processed for culturing without delay. Significance and Impact of the Study Epidemiological studies of bacterial diseases are typically limited to determination of pathogen presence/absence, yet quantitative assessments of pathogen load and genetic diversity can provide insights into disease progression and severity, likelihood of transmission and adaptive evolutionary potential. For studies of S. aureus where time or access to a microbiology laboratory may delay culturing, deep freezing or timely culturing will maximize the degree to which sampling results reflect source status.
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Affiliation(s)
- D Panisello Yagüe
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | - J Mihaljevic
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, USA
| | - M Mbegbu
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | - C V Wood
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | - C Hepp
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, USA
| | - S Kyman
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | - H Hornstra
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | - R Trotter
- Department of Anthropology, Northern Arizona University, Flagstaff, AZ, USA
| | - E Cope
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | - T Pearson
- Pathogen & Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
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8
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Tang C, Chen J, Zhang L, Zhang R, Zhang S, Ye S, Zhao Z, Yang D. Exploring the antibacterial mechanism of essential oils by membrane permeability, apoptosis and biofilm formation combination with proteomics analysis against methicillin-resistant staphylococcus aureus. Int J Med Microbiol 2020; 310:151435. [PMID: 32654773 DOI: 10.1016/j.ijmm.2020.151435] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Accepted: 06/01/2020] [Indexed: 12/12/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is one of the important causes of food poisoning and infectious diseases worldwide, it can produce a large number of virulence factors, enhance the colonization ability of the host so that it can quickly colonize and spread on the surface of the objects. Essential oil (EO) is one of the natural products with antimicrobial properties, can be used as an important source of antibacterial agent discovery, and has a broad development prospect. However, the unclear mechanisms of antibacterial action have become an obstacle to its further development and use. Hence, the objective of the present study was to reveal the antibacterial mechanism of EO from Amomum villosum Lour (A villosum Lour) against MRSA using label-free quantitative proteomics, investigate the effect of EO on the bacterial proteome, enzymatic activities and leakage of bacterial intracellular biomacromolecule. Proteomic analysis of MRSA in the presence of EO found that a total of 144 differential expressed proteins (DEPs) between the control and treatment group, in which 42 proteins were distinctly up-regulated and 102 proteins were down-regulated. Besides, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis, determination of cell membrane permeability and apoptosis, scanning electron microscopy (SEM) observations, bacterial surface hydrophobicity, and biofilm formation measurement were performed. Collectively, the above results indicated that the cell membrane damage by EO leads to the loss of membrane integrity and causes leakage of intracellular macromolecular substances, inhibition of protein, and biofilm synthesis. These findings manifested that EO exerts antibacterial effect by multiple avenues and expands our understanding of the antibacterial mechanism, it has potential application value in food preservative and pharmaceutical industries.
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Affiliation(s)
- Cailin Tang
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China; Department of Pharmacy, Guizhou Provincial People's Hospital, Guiyang, Guizhou, China
| | - Jiali Chen
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Lixia Zhang
- Yunnan Branch Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Jinghong, China
| | - Rongfei Zhang
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Sichen Zhang
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Shaoxia Ye
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Zhimin Zhao
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China
| | - Depo Yang
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, China.
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Saklani P, Lekshmi M, Nayak BB, Kumar S. Survival of Methicillin-Resistant Staphylococcus aureus in Fish and Shrimp under Different Storage Conditions. J Food Prot 2020; 83:844-848. [PMID: 31928413 DOI: 10.4315/jfp-19-546] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 01/08/2020] [Indexed: 11/11/2022]
Abstract
ABSTRACT Foods that are extensively handled during preparation and stored without refrigeration are often associated with staphylococcal food poisoning. This problem is more confounding when contaminating strains belong to the methicillin-resistant Staphylococcus aureus (MRSA) group. In this study, we investigated the survivability of MRSA in two seafood matrices under different storage conditions. MRSA was inoculated at 6 and 3 log CFU/g into all sample groups of peeled shrimp (Parapeneopsis stylifera) stored at -20°C, Bombay duck fish (Harpadon nehereus) stored in ice, and dried Bombay duck fish stored at 30 ± 2°C. The populations of MRSA in frozen peeled shrimp inoculated with MRSA at 6 log CFU/g were reduced by 1.52 log CFU/g, whereas in samples inoculated with 3 log CFU/g levels remained stable after 60 days of storage. In fresh Bombay duck fish inoculated with 6 log CFU/g and stored in ice for 18 days, MRSA levels decreased by 2.75 log CFU/g. In contrast, in fresh fish inoculated with 3 log CFU/g the total viable count increased by 3.02 log CFU/g over 16 days of ice storage. In dried fish stored at 30 ± 2°C, MRSA levels declined by 3.27 log CFU/g in samples inoculated with 6 log CFU/g and by 0.91 log CFU/g in samples inoculated with 3 log CFU/g. These results suggest that the survival of MRSA depends on the temperature of storage and the inoculum level. In our study, MRSA survival was higher when inoculated at 3 log CFU/g regardless of the seafood matrix and storage temperature. HIGHLIGHTS
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Affiliation(s)
- Pooja Saklani
- QC Laboratory, Post Harvest Technology, Indian Council of Agricultural Research, Central Institute of Fisheries Education, Versova, Mumbai 400061, India (ORCID: https://orcid.org/0000-0003-0223-9069 [S.K.])
| | - Manjusha Lekshmi
- QC Laboratory, Post Harvest Technology, Indian Council of Agricultural Research, Central Institute of Fisheries Education, Versova, Mumbai 400061, India (ORCID: https://orcid.org/0000-0003-0223-9069 [S.K.])
| | - Binaya Bhusan Nayak
- QC Laboratory, Post Harvest Technology, Indian Council of Agricultural Research, Central Institute of Fisheries Education, Versova, Mumbai 400061, India (ORCID: https://orcid.org/0000-0003-0223-9069 [S.K.])
| | - Sanath Kumar
- QC Laboratory, Post Harvest Technology, Indian Council of Agricultural Research, Central Institute of Fisheries Education, Versova, Mumbai 400061, India (ORCID: https://orcid.org/0000-0003-0223-9069 [S.K.])
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Khan MSI, Oh SW, Kim YJ. Power of Scanning Electron Microscopy and Energy Dispersive X-Ray Analysis in Rapid Microbial Detection and Identification at the Single Cell Level. Sci Rep 2020; 10:2368. [PMID: 32047250 PMCID: PMC7012924 DOI: 10.1038/s41598-020-59448-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 01/29/2020] [Indexed: 01/28/2023] Open
Abstract
The demand for rapid, consistent and easy-to-use techniques for detecting and identifying pathogens in various areas, such as clinical diagnosis, the pharmaceutical industry, environmental science and food inspection, is very important. In this study, the reference strains of six food-borne pathogens, namely, Escherichia coli 0157: H7 ATCC 43890, Cronobacter sakazakii ATCC 29004, Salmonella Typhimurium ATCC 43971, Staphylococcus aureus KCCM 40050, Bacillus subtilis ATCC 14579, and Listeria monocytogenes ATCC 19115, were chosen for scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis. In our study, the time-consuming sample preparation step for the microbial analysis under SEM was avoided, which makes this detection process notably rapid. Samples were loaded onto a 0.01-µm-thick silver (Ag) foil surface to avoid any charging effect. Two different excitation voltages, 10 kV and 5 kV, were used to determine the elemental information. Information obtained from SEM-EDX can distinguish individual single cells and detect viable and nonviable microorganisms. This work demonstrates that the combination of morphological and elemental information obtained from SEM-EDX analysis with the help of principal component analysis (PCA) enables the rapid identification of single microbial cells without following time-consuming microbiological cultivation methods.
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Affiliation(s)
- Muhammad Saiful Islam Khan
- Korea Food Research Institute, Consumer Safety Research Division, 55365, Wanju-Gun, Jeollabuk-Do, Republic of Korea
| | - Se-Wook Oh
- Department of Food and Nutrition, Kookmin University, 77 Jeongneung-ro, Seongbuk-gu, Seoul, 02707, Republic of Korea
| | - Yun-Ji Kim
- Korea Food Research Institute, Consumer Safety Research Division, 55365, Wanju-Gun, Jeollabuk-Do, Republic of Korea. .,Department of Food Biotechnology, University of Science and Technology, Daejeon, 305-350, Republic of Korea.
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11
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Tandem mass tag-based quantitative proteomic analysis reveal the inhibition mechanism of thyme essential oil against flagellum of Listeria monocytogenes. Food Res Int 2019; 125:108508. [DOI: 10.1016/j.foodres.2019.108508] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 06/03/2019] [Accepted: 06/21/2019] [Indexed: 11/23/2022]
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12
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Wang Y, Li X, Lu Y, Wang J, Suo B. Synergistic effect of cinnamaldehyde on the thermal inactivation of Listeria monocytogenes in ground pork. FOOD SCI TECHNOL INT 2019; 26:28-37. [PMID: 31399018 DOI: 10.1177/1082013219867190] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The aim of this study was to statistically evaluate the effect of a naturally food-derived cinnamaldehyde on the thermal inactivation of Listeria monocytogenes in ground pork. This study combined four concentrations of cinnamaldehyde (0, 0.1, 0.5, and 1.0% vol/wt) and four temperatures (55, 60, 65, and 70 ℃) to predict the thermal inactivation curves of L. monocytogenes. The Weibull model successfully described the primary thermal inactivation using the Integrated Pathogen Modeling Program. These results statistically proposed that the cinnamaldehyde supplementation in ground pork attenuates the thermo-tolerance of L. monocytogenes. The time for achieving a 5-log10 reduction of L. monocytogenes declined from 28.14 to 17.35 min at 55 ℃ when the ground pork sample was supplemented by 1% cinnamaldehyde, while the time declined from 1.95 to 0.34 min at 70 ℃. Thereafter, based on the 5.0-log10 lethality, secondary models were fitted by a selected polynomial model. The transmission electron microscopy revealed that cinnamaldehyde causes serious damage to membrane integrity and increases the occurrence of cell membrane rupture and leakage of cytoplasmic content under thermal treatment. Our model represents a mathematical tool that will help meat-product manufacturers to improve the efficacy of thermal processing ground pork supplemented with cinnamaldehyde.
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Affiliation(s)
- Yuexia Wang
- College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - Xiaoyan Li
- College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - Yangliu Lu
- College of Food Science and Technology, Henan Agricultural University, Zhengzhou, China
| | - Jianan Wang
- College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - Biao Suo
- College of Food Science and Technology, Henan Agricultural University, Zhengzhou, China
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Yu H, Liu M, Liu Y, Qin L, Jin M, Wang Z. Antimicrobial Activity and Mechanism of Action of Dracocephalum moldavica L. Extracts Against Clinical Isolates of Staphylococcus aureus. Front Microbiol 2019; 10:1249. [PMID: 31244794 PMCID: PMC6563755 DOI: 10.3389/fmicb.2019.01249] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 05/20/2019] [Indexed: 11/13/2022] Open
Abstract
Background: Dracocephalum moldavica L. is a popular traditional medicine used by many countries, which has a wide range of pharmacological effects. The aim of this work was to investigate the antimicrobial effects of D. moldavica L. extracts against clinical isolates of Staphylococcus aureus. Our results demonstrated that the minimal inhibitory concentration (MIC) for 50 and 90% of S. aureus isolates (MIC50 and MIC90) of the ethyl acetate (EtOAc) fraction from D. moldavica L. ethanol extract were 780 and 1,065 μg/ml, respectively. We further observed that the EtOAc fraction disrupted 24-h biofilm caused cell membrane damage and irregular cell shape. Additionally, the EtOAc fraction showed slight to moderate toxic effects on human epidermal keratinocyte (HaCaT) cells. Moreover, the results of the differential proteome revealed that 231 proteins were upregulated, while 61 proteins were downregulated in S. aureus after treatment with the EtOAc fraction. The differentially expressed proteins were functionally categorized by the Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. These proteins contribute to membrane damage, inhibition of biofilm formation, and changes in energy metabolism. Thus, the EtOAc fraction of D. moldavica L. ethanol extract, as a natural product, has the potential to be used as an antimicrobial agent to control the clinical isolates of S. aureus.
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Affiliation(s)
- Hui Yu
- The Second Affiliated Hospital, Baotou Medical College, Baotou, China
| | - Min Liu
- School of Public Health, Baotou Medical College, Baotou, China
| | - Yun Liu
- School of Public Health, Baotou Medical College, Baotou, China
| | - Lei Qin
- The Second Affiliated Hospital, Baotou Medical College, Baotou, China
| | - Min Jin
- School of Public Health, Baotou Medical College, Baotou, China
| | - Zhanli Wang
- The Second Affiliated Hospital, Baotou Medical College, Baotou, China
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