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Liu S, Pang H, Wang C, Wang Z, Wang M, Zhang Y, Zhang W, Sui Z. Rapid and accurate quantification of viable Bifidobacterium cells in milk powder with a propidium monoazide-antibiotic fluorescence in situ hybridization-flow cytometry method. J Dairy Sci 2024; 107:7678-7690. [PMID: 38908696 DOI: 10.3168/jds.2024-24876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 05/27/2024] [Indexed: 06/24/2024]
Abstract
Due to its beneficial effects on human health, Bifidobacterium is commonly added to milk powder. Accurate quantification of viable Bifidobacterium is essential for assessing the therapeutic efficacy of milk powder. In this study, we introduced a novel propidium monoazide (PMA)-antibiotic fluorescence in situ hybridization (AFISH)-flow cytometry (FC) method to rapidly and accurately quantify viable Bifidobacterium cells in milk powder. Briefly, Bifidobacterium cells were treated with chloramphenicol (CM) to increase their rRNA content, followed by staining with RNA-binding oligonucleotide probes, based on the AFISH technique. Then, the DNA-binding dye PMA was used to differentiate between viable and nonviable cells. The PMA-AFISH-FC method, including sample pretreatment, CM treatment, dual staining, and FC analysis, required approximately 2 h and was found to be better than the current methods. This is the first study to implement FC combined with PMA and an oligonucleotide probe for detecting Bifidobacterium.
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Affiliation(s)
- Siyuan Liu
- Center for Advanced Measurement Science, National Institute of Metrology, Beijing 100029, China; College of Food Science and Technology, Hebei Agricultural University, Baoding 071001, China; Hebei Key Laboratory of Analysis and Control for Zoonotic Pathogenic Microorganism, Hebei Agricultural University, Baoding 071001, China
| | - Huimin Pang
- Center for Advanced Measurement Science, National Institute of Metrology, Beijing 100029, China; College of Food Science and Technology, Hebei Agricultural University, Baoding 071001, China; Hebei Key Laboratory of Analysis and Control for Zoonotic Pathogenic Microorganism, Hebei Agricultural University, Baoding 071001, China
| | - Chenglong Wang
- Center for Advanced Measurement Science, National Institute of Metrology, Beijing 100029, China
| | - Ziquan Wang
- Center for Advanced Measurement Science, National Institute of Metrology, Beijing 100029, China
| | - Meng Wang
- Center for Advanced Measurement Science, National Institute of Metrology, Beijing 100029, China
| | - Yunzhe Zhang
- College of Food Science and Technology, Hebei Agricultural University, Baoding 071001, China; Hebei Key Laboratory of Analysis and Control for Zoonotic Pathogenic Microorganism, Hebei Agricultural University, Baoding 071001, China
| | - Wei Zhang
- College of Food Science and Technology, Hebei Agricultural University, Baoding 071001, China; Hebei Key Laboratory of Analysis and Control for Zoonotic Pathogenic Microorganism, Hebei Agricultural University, Baoding 071001, China.
| | - Zhiwei Sui
- Center for Advanced Measurement Science, National Institute of Metrology, Beijing 100029, China.
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Tracey H, Coates N, Hulme E, John D, Michael DR, Plummer SF. Insights into the enumeration of mixtures of probiotic bacteria by flow cytometry. BMC Microbiol 2023; 23:48. [PMID: 36849905 PMCID: PMC9969615 DOI: 10.1186/s12866-023-02792-2] [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: 10/07/2022] [Accepted: 02/13/2023] [Indexed: 03/01/2023] Open
Abstract
The use of flow cytometry to enumerate microorganisms is gaining traction over the traditional plate count technique on the basis of superior accuracy, precision and time-to-result. Here, we assessed the suitability of live/dead flow cytometry for the enumeration of mixed populations of probiotic bacteria (L. acidophilus, L. paracasei, L. plantarum, L. salivarius, B. lactis and B. bifidum) whilst comparing outcomes with plate counting. Using a novel gating strategy designed specifically for the enumeration of mixed populations, the application of flow cytometry resulted in the detection of higher numbers of viable bacteria with a greater level of repeatability than plate counting (RSD of 6.82 and 13.14% respectively). Across all multi-species blends tested, viable cell input was more accurately recovered by flow cytometry (101.8 ± 6.95%) than plate counts (81.37 ± 16.03%). However, when certain probiotic mixtures contained preparations with high numbers of non-viable cells in their total population, flow cytometry had the potential for overestimation of the viable population. Nevertheless, the comparative plate counts of these mixtures were low and variable, thus supporting the use of flow cytometry for the enumeration of viable bacteria in mixed populations.
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Affiliation(s)
- Harry Tracey
- Cultech Limited, Unit 2 Christchurch Road, Baglan Industrial Park, Port Talbot, UK
| | - Niall Coates
- Cultech Limited, Unit 2 Christchurch Road, Baglan Industrial Park, Port Talbot, UK.
| | - Eleri Hulme
- Cultech Limited, Unit 2 Christchurch Road, Baglan Industrial Park, Port Talbot, UK
| | - Daniel John
- Cultech Limited, Unit 2 Christchurch Road, Baglan Industrial Park, Port Talbot, UK
| | - Daryn Robert Michael
- Cultech Limited, Unit 2 Christchurch Road, Baglan Industrial Park, Port Talbot, UK
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Sorée M, Delavat F, Lambert C, Lozach S, Papin M, Petton B, Passerini D, Dégremont L, Hervio Heath D. Life history of oysters influences Vibrio parahaemolyticus accumulation in Pacific oysters (Crassostrea gigas). Environ Microbiol 2022; 24:4401-4410. [PMID: 35384247 PMCID: PMC9790381 DOI: 10.1111/1462-2920.15996] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 04/02/2022] [Indexed: 12/30/2022]
Abstract
Vibrio parahaemolyticus infection in humans is associated with raw oyster consumption. Evaluation of V. parahaemolyticus presence in oysters is of most interest because of the economic and public health issues that it represents. To explore V. parahaemolyticus accumulation and depuration in adult Crassostrea gigas, we developed a GFP-tagged V. parahaemolyticus strain (IFVp201-gfp+ ), as well as a rapid and efficient quantification method in C. gigas oysters haemolymph by flow cytometry. Impact of the life history of C. gigas on accumulation and depuration of V. parahaemolyticus IFVp201 was subsequently investigated. We found that naive oysters, i.e. grown in controlled facilities with UV treated seawater, accumulated significantly more IFVp201 than environmental oysters, i.e. grown in intertidal environment. We hypothesized that environmental oysters could have been immune primed, thus could limit V. parahaemolyticus accumulation. Meanwhile, both naive and environmental oysters had similar depuration rates.
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Affiliation(s)
- Marion Sorée
- Ifremer, MASAENantesF‐44311France,Ifremer, SGMMPlouzanéF‐29280France
| | | | | | - Solen Lozach
- Univ Brest, Ifremer, CNRS, IRD, LEMARPlouzanéF‐29280France
| | | | - Bruno Petton
- Univ Brest, Ifremer, CNRS, IRD, LEMARPlouzanéF‐29280France
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Liu X, Meng Q, Wu F, Zhang C, Tan X, Wan C. Enhanced biogas production in anaerobic digestion of sludge medicated by biochar prepared from excess sludge: Role of persistent free radicals and electron mediators. BIORESOURCE TECHNOLOGY 2022; 347:126422. [PMID: 34838963 DOI: 10.1016/j.biortech.2021.126422] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/17/2021] [Accepted: 11/21/2021] [Indexed: 06/13/2023]
Abstract
The addition of biochars to promote the efficiency of anaerobic digestion (AD) has widely received concerns. However, the role of persistent free radicals (PFRs) and the electron transfer ability of biochar in AD has not yet been noticed. In this study, biochars were prepared from excess sludge under 400 °C (B400) or 600 °C (B600) and different ratios of sludge to biochar (5:1, 10:1, 20:1) were applied in the AD of sludge. The results verified that PFRs in biochar participated in the sterilization of microorganisms in sludge, resulting in the release of organic matters. Similar to electron mediators, biochars possessed electron exchangeability and the addition of biochars boosted the biogas production by maximum of 54.5%. The enhancing effect of B400 surpassed that of B600 as high temperature destroyed functional groups and reduced the defect degree of biochar. This study achieved in-situ resource utilization and provided references for the improvement of anaerobic digestion.
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Affiliation(s)
- Xiang Liu
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200438, China
| | - Qingting Meng
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200438, China
| | - Fengjie Wu
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200438, China
| | - Chen Zhang
- Shanghai Municipal Engineering Design Institute Group Co Ltd, Shanghai 200092, China
| | - Xuejun Tan
- Shanghai Municipal Engineering Design Institute Group Co Ltd, Shanghai 200092, China
| | - Chunli Wan
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200438, China.
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Obtaining paraprobiotics from Lactobacilus acidophilus, Lacticaseibacillus casei and Bifidobacterium animalis using six inactivation methods: Impacts on the cultivability, integrity, physiology, and morphology. J Funct Foods 2021. [DOI: 10.1016/j.jff.2021.104826] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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