1
|
Qin X, Gong M, Li Y, Huo Y, Li D, Li P, Chang X, Li K, Yang H. Psychrophilic phage phiGM22-3 efficiently controls Pseudomonas fluorescens contamination in cold-stored milk. Int J Food Microbiol 2024; 411:110525. [PMID: 38128262 DOI: 10.1016/j.ijfoodmicro.2023.110525] [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: 09/09/2023] [Revised: 11/30/2023] [Accepted: 12/10/2023] [Indexed: 12/23/2023]
Abstract
Pseudomonas fluorescens is a common spoilage causing microbe found in milk. Antibiotic preservatives may cause emergence of multidrug resistance, posing food safety related risks to public health. Phage treatment may be used as an alternative to antibiotics in controlling P. fluorescens contaminations. Here we reported that P. fluorescens phage phiGM22-3 reproduced rapidly over a broad temperature range of 4 through 30°C, and the optimum growth of phiGM22-3 occurred at 10°C, indicating that it was a psychrophilic virus. Genome analysis revealed that phiGM22-3 has a genome of 42,662 bp with an identical terminal direct repeat sequence of 328 bp and encodes 58 predicted proteins. Evidence revealed that phiGM22-3 recognized lipopolysaccharides (LPS) as receptor for infection. Additionally, two phage mutants phiMX2 and phiMX8 with different host ranges were identified in the phiGM22-3 population. Phage killing efficiency of P. fluorescens cells artificially inoculated in milk was evaluated. Phage phiGM22-3 and the cocktails containing phiMX2 and phiMX8 can lyse almost 100% bacterial cells at 4°C within 24 h. Taken together, our data indicated that the psychrophilic virus phiGM22-3 and its two mutants can efficiently inhibit bacteria growth at 4°C, showing a great potential to be used as alternatives to conventional antibiotics against P. fluorescens in refrigerated foods.
Collapse
Affiliation(s)
- Xuying Qin
- Key Laboratory of Industrial Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Mengxin Gong
- Key Laboratory of Industrial Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Yutong Li
- Key Laboratory of Industrial Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Yansheng Huo
- Key Laboratory of Industrial Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Donghang Li
- Key Laboratory of Industrial Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Peize Li
- Key Laboratory of Industrial Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Xinxin Chang
- Key Laboratory of Industrial Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Kexin Li
- Key Laboratory of Industrial Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Hongjiang Yang
- Key Laboratory of Industrial Microbiology of the Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China.
| |
Collapse
|
2
|
Tayyarcan EK, Boyaci IH. Isolation, characterization, and application of bacteriophage cocktails for the biocontrol of Pseudomonas fluorescens group strains in whole and skimmed milk. Braz J Microbiol 2023; 54:3061-3071. [PMID: 37914971 PMCID: PMC10689657 DOI: 10.1007/s42770-023-01164-2] [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: 05/03/2023] [Accepted: 10/19/2023] [Indexed: 11/03/2023] Open
Abstract
Pseudomonas fluorescens group strains can lead to spoilage of milk as well as loss of quality in dairy products through their heat-resistant enzymes. Phages are important alternatives for combating spoilage bacteria in food industry and used successfully in many applications. The aim of this study was the isolation and characterization of phages and to assess the efficiency of a phage cocktail in whole and skimmed milk. For this purpose, phages effective against Pseudomonas fluorescens (L23.2), Pseudomonas tolaasii (P22.1), and Pseudomonas rhodesiae (A11.1) were isolated. Their host range was found to be highly specific, and the transmission electron micrographs indicates that they belonged to Tectiviridae family. Their genome sizes were found to be vary between 38.3 and 53.5 kb. The latent periods and burst sizes were determined as 15, 10, 15 min and 91, 20, 80 PFU/infected cell for L23.2, P22.1, and A11.1, respectively. All three phages were found to be sensitive to low pH and high temperature. The effect of the phage cocktail was monitored in milk with different fat contents during storage at 4 °C for 5 days. As a result, bacterial reductions up to 4.09 and 5.29 log-units were observed for the whole and skimmed milk, respectively. Thus, the efficacy of a phage cocktail against a bacterial mixture of different P. fluorescens strains was tested in milk samples with different fat contents in accordance with real-life scenarios for the first time.
Collapse
|
3
|
Yan N, Xia H, Hou W, Wang H, Wang H, Zhou M. Biological Characterization of Pseudomonas fluorescens Phage Pf17397_F_PD1 and Its Application in Food Preservation. J Food Prot 2023; 86:100125. [PMID: 37406883 DOI: 10.1016/j.jfp.2023.100125] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 06/27/2023] [Accepted: 06/30/2023] [Indexed: 07/07/2023]
Abstract
In order to explore the application prospects of phages for controlling bacterial contamination, a lytic phage Pf17397_F_PD1 (Later abbreviated as PD1) was isolated from fish guts using Pseudomonas fluorescens ATCC 17397 as the host bacterium. The phage displayed short latency (18 min), long lysis period (212 min), and high lysis volume (1.47 × 102 PFU/each cell). It displayed wide temperature (30-70°C) and pH (4-11) tolerance. Genomic comparison revealed a maximum sequence identity of 48.65% between phage PD1 and other identified phages, indicating that PD1 was a new phage. The phage PD1 significantly inhibited the growth of P. fluorescens in milk and grass carp at 4°C and 25°C. Compared to the negative control, bacterial levels in milk stored at 25°C for 48 h were reduced by 2.71 log CFU/mL and 2.84 log CFU/mL at the multiplicity of infection (MOI) of 100 and 1,000, respectively. In contrast, when grass carp were stored at 25°C for 24 h, the bacterial load was reduced by 1.28 log CFU/g and 2.64 log CFU/g compared to the control (MOI of 100 and 1,000). When the phage was applied for preservation of grass carp blocks, total volatile salt nitrogen (TVB-N) values of phage-treated samples increased by 6.8 mg/100 g and 7.5 mg/100 g at MOI of 100 and 1,000, respectively, after 7 days of storage, which was significantly lower than that of the control group (15.83 mg/100 g). This study showed that phage PD1 was a good natural biological antimicrobial agent against P. fluorescens ATCC 17397.
Collapse
Affiliation(s)
- Na Yan
- School of Food Science and Engineering, Wuhan Polytechnic University, Wuhan 430000, China
| | - Hai Xia
- School of Life Science and Technology, Wuhan Polytechnic University, Wuhan 430000, China
| | - Wenfu Hou
- School of Food Science and Engineering, Wuhan Polytechnic University, Wuhan 430000, China
| | - Huajuan Wang
- School of Food Science and Engineering, Wuhan Polytechnic University, Wuhan 430000, China
| | - Hongxun Wang
- School of Food Science and Engineering, Wuhan Polytechnic University, Wuhan 430000, China.
| | - Min Zhou
- School of Food Science and Engineering, Wuhan Polytechnic University, Wuhan 430000, China.
| |
Collapse
|
4
|
Xia H, Yu B, Jiang Y, Cheng R, Lu X, Wu H, Zhu B. Psychrophilic phage VSW-3 RNA polymerase reduces both terminal and full-length dsRNA byproducts in in vitro transcription. RNA Biol 2022; 19:1130-1142. [DOI: 10.1080/15476286.2022.2139113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Affiliation(s)
- Heng Xia
- Key Laboratory of Molecular Biophysics, the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Bingbing Yu
- Key Laboratory of Molecular Biophysics, the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Yixin Jiang
- Key Laboratory of Molecular Biophysics, the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Rui Cheng
- Key Laboratory of Molecular Biophysics, the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Xueling Lu
- Key Laboratory of Molecular Biophysics, the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Hui Wu
- Key Laboratory of Molecular Biophysics, the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Bin Zhu
- Key Laboratory of Molecular Biophysics, the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
- Shenzhen Huazhong University of Science and Technology Research Institute, Shenzhen, China
| |
Collapse
|
5
|
Virus-Host Interactions and Genetic Diversity of Antarctic Sea Ice Bacteriophages. mBio 2022; 13:e0065122. [PMID: 35532161 PMCID: PMC9239159 DOI: 10.1128/mbio.00651-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although we know the generally appreciated significant roles of microbes in sea ice and polar waters, detailed studies of virus-host systems from such environments have been so far limited by only a few available isolates. Here, we investigated infectivity under various conditions, infection cycles, and genetic diversity of the following Antarctic sea ice bacteriophages: Paraglaciecola Antarctic GD virus 1 (PANV1), Paraglaciecola Antarctic JLT virus 2 (PANV2), Octadecabacter Antarctic BD virus 1 (OANV1), and Octadecabacter Antarctic DB virus 2 (OANV2). The phages infect common sea ice bacteria belonging to the genera Paraglaciecola or Octadecabacter. Although the phages are marine and cold-active, replicating at 0°C to 5°C, they all survived temporal incubations at ≥30°C and remained infectious without any salts or supplemented only with magnesium, suggesting a robust virion assembly maintaining integrity under a wide range of conditions. Host recognition in the cold proved to be effective, and the release of progeny viruses occurred as a result of cell lysis. The analysis of viral genome sequences showed that nearly one-half of the gene products of each virus are unique, highlighting that sea ice harbors unexplored virus diversity. Based on predicted genes typical for tailed double-stranded DNA phages, we suggest placing the four studied viruses in the class Caudoviricetes. Searching against viral sequences from metagenomic assemblies, we revealed that related viruses are not restricted to Antarctica but are also found in distant marine environments.
Collapse
|
6
|
Pan L, Li D, Sun Z, Lin W, Hong B, Qin W, Xu L, Liu W, Zhou Q, Wang F, Cai R, Qian M, Tong Y. First Characterization of a Hafnia Phage Reveals Extraordinarily Large Burst Size and Unusual Plaque Polymorphism. Front Microbiol 2022; 12:754331. [PMID: 35211099 PMCID: PMC8861465 DOI: 10.3389/fmicb.2021.754331] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 12/20/2021] [Indexed: 01/25/2023] Open
Abstract
A unique lytic phage infecting Hafnia paralvei was isolated and identified. Hafnia phage Ca belongs to the family Autographiviridae, possessing an icosahedral head with a diameter of 55 nm and a short non-contractile tail. Unusually, the burst size of Hafnia phage Ca of 10,292 ± 1,097 plaque-forming units (PFUs)/cell is much larger than other dsDNA phages reported before. Compared to the genome of the related phage, Hafnia phage Ca genome contains extra genes including DNA mimic ocr, dGTP triphosphohydrolase inhibitor, endonuclease, endonuclease VII, and HNH homing endonuclease gene. Extraordinarily, the phage developed different sizes of plaques when a single plaque was picked out and inoculated on a double-layer Luria broth agar plate with its host. Furthermore, varied packaging tightness for the tails of Hafnia phage Ca was observed (tail length: 4.35–45.92 nm). Most of the tails appeared to be like a cone with appendages, some were dot-like, bun-like, table tennis racket handle-like, and ponytail-like. Although the complete genome of Hafnia phage Ca is 40,286 bp, an incomplete genome with a deletion of a 397-bp fragment, containing one ORF predicted as HNH homing endonuclease gene (HEG), was also found by high throughput sequencing. Most of the genome of the virus particles in large plaques is complete (>98%), while most of the genome of the virus particles in small plaques is incomplete (>98%), and the abundance of both of them in medium-sized plaques is similar (complete, 40%; incomplete, 60%). In an experiment to see if the phage could be protective to brocade carps intramuscularly injected with H. paralvei LY-23 and phage Ca, the protection rate of Hafnia phage Ca to brocade carp (Cyprinus aka Koi) against H. paralvei was 33.38% (0.01 < p < 0.05). This study highlights some new insights into the peculiar biological and genomic characteristics of phage.
Collapse
Affiliation(s)
- Lingting Pan
- Key Laboratory of Marine Biotechnology, School of Marine Sciences, Ningbo University, Ningbo, China.,College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Dengfeng Li
- Key Laboratory of Marine Biotechnology, School of Marine Sciences, Ningbo University, Ningbo, China
| | - Zhitong Sun
- Key Laboratory of Marine Biotechnology, School of Marine Sciences, Ningbo University, Ningbo, China
| | - Wei Lin
- Key Laboratory of Marine Biotechnology, School of Marine Sciences, Ningbo University, Ningbo, China.,College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Binxin Hong
- Key Laboratory of Marine Biotechnology, School of Marine Sciences, Ningbo University, Ningbo, China
| | - Weinan Qin
- Key Laboratory of Marine Biotechnology, School of Marine Sciences, Ningbo University, Ningbo, China
| | - Lihua Xu
- Key Laboratory of Marine Biotechnology, School of Marine Sciences, Ningbo University, Ningbo, China
| | - Wencai Liu
- Key Laboratory of Marine Biotechnology, School of Marine Sciences, Ningbo University, Ningbo, China
| | - Qin Zhou
- Key Laboratory of Marine Biotechnology, School of Marine Sciences, Ningbo University, Ningbo, China
| | - Fei Wang
- Key Laboratory of Marine Biotechnology, School of Marine Sciences, Ningbo University, Ningbo, China
| | - Ruqian Cai
- Key Laboratory of Marine Biotechnology, School of Marine Sciences, Ningbo University, Ningbo, China
| | - Minhua Qian
- Key Laboratory of Marine Biotechnology, School of Marine Sciences, Ningbo University, Ningbo, China
| | - Yigang Tong
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| |
Collapse
|
7
|
Ding Y, Zhang D, Zhao X, Tan W, Zheng X, Zhang Q, Ji X, Wei Y. Autoinducer-2-mediated quorum-sensing system resists T4 phage infection in Escherichia coli. J Basic Microbiol 2021; 61:1113-1123. [PMID: 34783039 DOI: 10.1002/jobm.202100344] [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: 07/19/2021] [Revised: 09/26/2021] [Accepted: 10/31/2021] [Indexed: 11/12/2022]
Abstract
In response to the restriction of nutrients and predation by natural enemies, bacteria have evolved complex coping strategies to ensure the reproduction and survival of individual species. Quorum sensing (QS) is involved in the bacterial response to phage predation and regulation of cellular metabolism. However, to date, no clear evidence exists regarding the involvement of autoinducer-2 (AI-2)-mediated QS systems in Escherichia coli in response to the challenges of nutrient restriction and phage infection. In this study, the role of the AI-2-mediated QS system in resisting T4 phage infection and regulating cell mechanisms in E. coli was revealed for the first time. This effect of the AI-2-mediated QS was achieved by simultaneously downregulating the T4 absorption site and carbon and glucose metabolism. Additionally, we found that lsrB, a metabolic brake, participates in AI-2-mediated regulation and maintenance of the normal metabolic balance of cells. The novel phage defense strategy and regulation and maintenance of cellular metabolism effectively limited the expansion of the phage population.
Collapse
Affiliation(s)
- Yafang Ding
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Dongfang Zhang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Xiaoman Zhao
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Wenzhang Tan
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Xiaodan Zheng
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Qi Zhang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Xiuling Ji
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Yunlin Wei
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| |
Collapse
|
8
|
Nascimento ECD, Sabino MC, Corguinha LDR, Targino BN, Lange CC, Pinto CLDO, Pinto PDF, Vidigal PMP, Sant'Ana AS, Hungaro HM. Lytic bacteriophages UFJF_PfDIW6 and UFJF_PfSW6 prevent Pseudomonas fluorescens growth in vitro and the proteolytic-caused spoilage of raw milk during chilled storage. Food Microbiol 2021; 101:103892. [PMID: 34579852 DOI: 10.1016/j.fm.2021.103892] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 08/20/2021] [Accepted: 08/23/2021] [Indexed: 11/04/2022]
Abstract
In this study, P. fluorescens-infecting phages were isolated, characterized, and evaluated to their potential to control the bacterial counts and, consequently, the proteolytic spoilage of raw milk during cold storage. The UFJF_PfDIW6 and UFJF_PfSW6 phages showed titers of 9.7 and 7.6 log PFU/ml; latent period of 115 and 25 min, and burst size of 145 and 25 PFU/infected cell, respectively. They also were highly specific to the host bacterium, morphologically classified as the Podoviridae family, stable at pH 5 to 11 and were not inactivated at 63 °C or 72 °C for 30 min. These phages found to be effective against P. fluorescens, reducing bacterial count throughout the entire exponential growth phase in broth formulated with milk at both 4 °C and 10 °C. This effect on bacteria growth led to inhibition by at least 2 days in proteases production, delaying the degradation of milk proteins. When applied together in raw milk stored at 4 °C, they reduced the total bacteria, psychrotrophic, and Pseudomonas by 3 log CFU/ml. This study's findings indicate that these phages have a great potential to prevent the growth of Pseudomonas and, consequently, to retard proteolytic spoilage of raw milk during chilled storage.
Collapse
Affiliation(s)
- Edilane Cristina do Nascimento
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, Federal University of Juiz de Fora, Juiz de Fora, M.G, Brazil
| | - Melissa Correa Sabino
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, Federal University of Juiz de Fora, Juiz de Fora, M.G, Brazil
| | - Lucas da Roza Corguinha
- Department of Nutrition, Institute of Biological Sciences, Federal University of Juiz de Fora, Juiz de Fora, M.G, Brazil
| | - Brenda Neres Targino
- Department of Nutrition, Institute of Biological Sciences, Federal University of Juiz de Fora, Juiz de Fora, M.G, Brazil
| | - Carla Cristine Lange
- Brazilian Agricultural Research Corporation (EMBRAPA), Embrapa Dairy Cattle, Juiz de Fora, M.G, Brazil
| | | | - Priscila de Faria Pinto
- Department of Biochemistry, Institute of Biological Sciences, Federal University of Juiz de Fora, Juiz de Fora, M.G, Brazil
| | | | - Anderson S Sant'Ana
- Department of Food Science and Nutrition, Faculty of Food Engineering, University of Campinas, Campinas, S.P, Brazil
| | - Humberto Moreira Hungaro
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, Federal University of Juiz de Fora, Juiz de Fora, M.G, Brazil.
| |
Collapse
|
9
|
Bonetti G, Trevathan-Tackett SM, Carnell PE, Macreadie PI. The potential of viruses to influence the magnitude of greenhouse gas emissions in an inland wetland. WATER RESEARCH 2021; 193:116875. [PMID: 33550166 DOI: 10.1016/j.watres.2021.116875] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 01/21/2021] [Accepted: 01/24/2021] [Indexed: 06/12/2023]
Abstract
Wetlands are among the earth's most efficient ecosystems for carbon sequestration, but can also emit potent greenhouse gases (GHGs) depending on how they are managed. Global management strategies have sought to maximize carbon drawdown by wetlands by manipulating wetland hydrology to inhibit bacterially-mediated emissions. However, it has recently been hypothesized within wetlands that viruses have the potential to dictate the magnitude and direction of GHG emissions by attacking prokaryotes involved in the carbon cycle. Here we tested this hypothesis in a whole-ecosystem manipulation by hydrologically-restoring a degraded wetland ('rewetting') and investigated the changes in GHG emissions, prokaryotes, viruses, and virus-host interactions. We found that hydrological restoration significantly increased prokaryotic diversity, methanogenic Methanomicrobia, as well as putative iron/sulfate-cyclers (Geobacteraceae), nitrogen-cyclers (Nitrosomonadaceae), and fermentative bacteria (Koribacteraceae). These results provide insights into successional microbial community shifts during rehabilitation. Additionally, in response to watering, viral-induced prokaryotic mortality declined by 77%, resulting in limited carbon released by viral shunt that was significantly correlated with the 2.8-fold reduction in wetland carbon emissions. Our findings highlight, for the first time, the potential implications of viral infections in soil prokaryotes on wetland greenhouse gas dynamics and confirm the importance of wetland rehabilitation as a tool to offset carbon emissions.
Collapse
Affiliation(s)
- Giuditta Bonetti
- Deakin University, Centre for Integrative Ecology, School of Life and Environmental Sciences, Burwood Campus, Victoria 3125, Australia..
| | - Stacey M Trevathan-Tackett
- Deakin University, Centre for Integrative Ecology, School of Life and Environmental Sciences, Burwood Campus, Victoria 3125, Australia..
| | - Paul E Carnell
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Geelong, Queenscliff Campus, Queenscliff, VIC 3225, Australia.
| | - Peter I Macreadie
- Deakin University, Centre for Integrative Ecology, School of Life and Environmental Sciences, Burwood Campus, Victoria 3125, Australia..
| |
Collapse
|
10
|
Characterization and Genome Analysis of a Novel Mu-like Phage VW-6B Isolated from the Napahai Plateau Wetland of China. Curr Microbiol 2020; 78:150-158. [PMID: 33150466 DOI: 10.1007/s00284-020-02277-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 10/27/2020] [Indexed: 10/23/2022]
Abstract
Although bacteriophages are more numerous and have smaller genomes than their bacterial hosts, relatively few have their genomes sequenced. Here, we isolated the Pseudomonas fluorescens bacteriophage from Napahai plateau wetland and performed de novo genome sequencing. Based on the previous biological characteristics and bioinformatics analysis, it was determined that VW-6B was a linear double-stranded DNA (dsDNA) phage with 35,306 bp, with 56.76% G+C content and 197 bp tandem repeats. The VW-6B genome contained 46 open-reading frames (ORFs), and no tRNA genes were found. Based on phage genome structure, sequence comparison, and collinear analysis, VW-6B should be classified into the family Siphoviridae and be considered as a member of a new species in the Mu-like phage. The newly isolated bacteriophage can specifically infect P. fluorescens, which further enriches the diversity of known bacteriophages and provides a basis for the subsequent research and application of bacteriophages.
Collapse
|
11
|
Virus and Potential Host Microbes from Viral-Enriched Metagenomic Characterization in the High-Altitude Wetland, Salar de Huasco, Chile. Microorganisms 2020; 8:microorganisms8071077. [PMID: 32698305 PMCID: PMC7409041 DOI: 10.3390/microorganisms8071077] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 07/02/2020] [Accepted: 07/03/2020] [Indexed: 12/18/2022] Open
Abstract
Salar de Huasco is a wetland in the Andes mountains, located 3800 m above sea level at the Chilean Altiplano. Here we present a study aimed at characterizing the viral fraction and the microbial communities through metagenomic analysis. Two ponds (H0 and H3) were examined in November 2015. Water samples were processed using tangential flow filtration to obtain metagenomes from which the DNA fraction of the sample was amplified and sequenced (HiSeq system, Illumina). The ponds were characterized by freshwater and the viral-like particles to picoplankton ratio was 12.1 and 2.3 for H0 and H3, respectively. A great number of unassigned viral sequences were found in H0 (55.8%) and H3 (32.8%), followed by the family Fuselloviridae 20.8% (H0) and other less relatively abundant groups such as Microviridae (H0, 11.7% and H3, 3.3%) and Inoviridae (H3, 2.7%). The dominant viral sequences in both metagenomes belong to the order Caudovirales, with Siphoviridae being the most important family, especially in H3 (32.7%). The most important bacteria phyla were Proteobacteria, Bacteroidetes and Firmicutes in both sites, followed by Cyanobacteria (H0). Genes encoding lysogenic and lytic enzymes (i.e., recombinases and integrases) were found in H0 and H3, indicating a potential for active viral replication at the time of sampling; this was supported by the presence of viral metabolic auxiliary genes at both sites (e.g., cysteine hydrolase). In total, our study indicates a great novelty of viral groups, differences in taxonomic diversity and replication pathways between sites, which contribute to a better understanding of how viruses balance the cycling of energy and matter in this extreme environment.
Collapse
|
12
|
Bonetti G, Trevathan-Tackett SM, Carnell PE, Macreadie PI. Implication of Viral Infections for Greenhouse Gas Dynamics in Freshwater Wetlands: Challenges and Perspectives. Front Microbiol 2019; 10:1962. [PMID: 31507569 PMCID: PMC6718870 DOI: 10.3389/fmicb.2019.01962] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 08/09/2019] [Indexed: 01/07/2023] Open
Abstract
Viruses are non-living, acellular entities, and the most abundant biological agents on earth. They are widely acknowledged as having the capacity to influence global biogeochemical cycles by infecting the bacterial and archaeal populations that regulate carbon and nutrient turnover. Evidence suggests that the majority of viruses in wetlands are bacteriophages, but despite their importance, studies on how viruses control the prokaryotic community and the concomitant impacts on ecosystem function (such as carbon cycling and greenhouse gas flux) in wetlands are rare. Here we investigate virus-prokaryote interactions in freshwater wetland ecosystems in the context of their potential influence on biogeochemical cycling. Specifically, we (1) synthesize existing literature to establish current understanding of virus-prokaryote interactions, focusing on the implications for wetland greenhouse gas dynamics and (2) identify future research priorities. Viral dynamics in freshwater wetlands have received much less attention compared to those in marine ecosystems. However, based on our literature review, within the last 10 years, viral ecology studies on freshwater wetlands have increased twofold. Despite this increase in literature, the potential implication of viral infections on greenhouse gas emission dynamics is still a knowledge gap. We hypothesize that the rate of greenhouse gas emissions and the pool of sequestered carbon could be strongly linked to the type and rate of viral infection. Viral replication mechanism choice will consequently influence the microbial efficiency of organic matter assimilation and thus the ultimate fate of carbon as a greenhouse gas or stored in soils.
Collapse
Affiliation(s)
- Giuditta Bonetti
- Faculty of Science, Engineering and Built Environment, School of Life and Environmental Sciences, Centre for Integrative Ecology, Deakin University, Burwood, VIC, Australia
| | - Stacey M Trevathan-Tackett
- Faculty of Science, Engineering and Built Environment, School of Life and Environmental Sciences, Centre for Integrative Ecology, Deakin University, Burwood, VIC, Australia
| | - Paul E Carnell
- Faculty of Science, Engineering and Built Environment, School of Life and Environmental Sciences, Centre for Integrative Ecology, Deakin University, Burwood, VIC, Australia
| | - Peter I Macreadie
- Faculty of Science, Engineering and Built Environment, School of Life and Environmental Sciences, Centre for Integrative Ecology, Deakin University, Burwood, VIC, Australia
| |
Collapse
|
13
|
Tanaka C, Yamada K, Takeuchi H, Inokuchi Y, Kashiwagi A, Toba T. A Lytic Bacteriophage for Controlling Pseudomonas lactis in Raw Cow's Milk. Appl Environ Microbiol 2018; 84:e00111-18. [PMID: 29980554 PMCID: PMC6122002 DOI: 10.1128/aem.00111-18] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 06/29/2018] [Indexed: 12/18/2022] Open
Abstract
The control of bacterial growth during milk processing is crucial for the quality maintenance of commercial milk and milk products. During a period of cold storage prior to heat treatments, some psychrotrophic bacteria grow and produce extracellular heat-resistant lipases and proteases that cause product defects. The use of lytic bacteriophages (phages) that infect and kill bacteria could be a useful tool for suppressing bacterial growth during this cold storage phase. In this study, we isolated a Pseudomonas lactis strain and a phage from raw cow's milk. Quantitative characterization of the phage was used to elucidate whether this phage was active under low temperatures and neutral pH and whether it was inactivated during pasteurization. Phage titer determination was possible under conditions ranging from pH 4 to 9 and from 3°C to 25°C; the phage was inactivated under pasteurization conditions at 63°C for 30 min. Furthermore, we showed that this phage reduced viable bacterial cell counts in both skim and whole milk. The results of this study represent the potential uses of phages for controlling psychrotrophic bacterial growth in raw cow's milk during cold storage.IMPORTANCE Suppression of bacterial growth in raw milk under cold storage is crucial for the quality control of commercially supplied milk. The use of lytic phages as low-cost microbicides is an attractive prospect. Due to strict host specificities, phages must be isolated from the raw milk where the host bacteria are growing. We first isolated the P. lactis bacterial strain and then the phage infecting that strain. Partial phage genomic analysis showed that this is a newly isolated phage, different from any previously reported. This study reports a lytic phage for P. lactis, and we have presented evidence here that this phage reduced viable bacterial cell counts not only in rich medium but also in skim and whole milk. As a result, we have concluded that the phage reported in this study would be useful in milk processing.
Collapse
Affiliation(s)
- Chikage Tanaka
- Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Aomori, Japan
| | - Kohsuke Yamada
- Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Aomori, Japan
| | - Honami Takeuchi
- Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Aomori, Japan
| | - Yoshio Inokuchi
- Faculty of Science and Engineering, Teikyo University, Utsunomiya, Tochigi, Japan
| | - Akiko Kashiwagi
- Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Aomori, Japan
| | - Takahiro Toba
- Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Aomori, Japan
| |
Collapse
|
14
|
Xiang Y, Wang S, Li J, Wei Y, Zhang Q, Lin L, Ji X. Isolation and characterization of two lytic cold-active bacteriophages infecting Pseudomonas fluorescens from the Napahai plateau wetland. Can J Microbiol 2017; 64:183-190. [PMID: 29253355 DOI: 10.1139/cjm-2017-0572] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
As the "kidneys of the Earth", wetlands play important roles as biodiversity reservoirs, in water purification, and in flood control. In this study, 2 lytic cold-active bacteriophages, named VW-6S and VW-6B, infecting Pseudomonas fluorescens W-6 cells from the Napahai plateau wetland in China were isolated and characterized. Electron microscopy showed that both VW-6S and VW-6B had an icosahedral head (66.7 and 61.1 nm, respectively) and a long tail (8.3 nm width × 233.3 nm length and 11.1 nm width × 166.7 nm length, respectively). The bacteriophages VW-6S and VW-6B were classified as Siphoviridae and had an approximate genome size of 30-40 kb. The latent and burst periods of VW-6S were 60 and 30 min, whereas those of VW-6B were 30 and 30 min, respectively. The optimal pH values for the bacteriophages VW-6S and VW-6B were 8.0 and 10.0, respectively, and their activity decreased rapidly at temperatures higher than 60 °C. These cold-active bacteriophages provide good materials for further study of cold-adaptation mechanisms and interaction with the host P. fluorescens.
Collapse
Affiliation(s)
- Yingying Xiang
- a Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China.,b Department of Stomatology, Yan'an Hospital Affiliated to Kunming Medical University, Kunming 650031, China
| | - Shuang Wang
- a Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China
| | - Jiankai Li
- a Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China
| | - Yunlin Wei
- a Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China
| | - Qi Zhang
- a Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China
| | - Lianbing Lin
- a Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China
| | - Xiuling Ji
- a Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China
| |
Collapse
|