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Sisson HM, Fagerlund RD, Jackson SA, Briers Y, Warring SL, Fineran PC. Antibacterial synergy between a phage endolysin and citric acid against the Gram-negative kiwifruit pathogen Pseudomonas syringae pv. actinidiae. Appl Environ Microbiol 2024; 90:e0184623. [PMID: 38319087 PMCID: PMC10952447 DOI: 10.1128/aem.01846-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 01/04/2024] [Indexed: 02/07/2024] Open
Abstract
Horticultural diseases caused by bacterial pathogens provide an obstacle to crop production globally. Management of the infection of kiwifruit by the Gram-negative phytopathogen Pseudomonas syringae pv. actinidiae (Psa) currently includes copper and antibiotics. However, the emergence of bacterial resistance and a changing regulatory landscape are providing the impetus to develop environmentally sustainable antimicrobials. One potential strategy is the use of bacteriophage endolysins, which degrade peptidoglycan during normal phage replication, causing cell lysis and the release of new viral progeny. Exogenous use of endolysins as antimicrobials is impaired by the outer membrane of Gram-negative bacteria that provides an impermeable barrier and prevents endolysins from accessing their target peptidoglycan. Here, we describe the synergy between citric acid and a phage endolysin, which results in a reduction of viable Psa below detection. We show that citric acid drives the destabilization of the outer membrane via acidification and sequestration of divalent cations from the lipopolysaccharide, which is followed by the degradation of the peptidoglycan by the endolysin. Scanning electron microscopy revealed clear morphological differences, indicating cell lysis following the endolysin-citric acid treatment. These results show the potential for citric acid-endolysin combinations as a possible antimicrobial approach in agricultural applications. IMPORTANCE The phytopathogen Pseudomonas syringae pv. actinidiae (Psa) causes major impacts to kiwifruit horticulture, and the current control strategies are heavily reliant on copper and antibiotics. The environmental impact and increasing resistance to these agrichemicals are driving interest in alternative antimicrobials including bacteriophage-derived therapies. In this study, we characterize the endolysin from the Otagovirus Psa374 which infects Psa. When combined with citric acid, this endolysin displays an impressive antibacterial synergy to reduce viable Psa below the limit of detection. The use of citric acid as a synergistic agent with endolysins has not been extensively studied and has never been evaluated against a plant pathogen. We determined that the synergy involved a combination of the chelation activity of citric acid, acidic pH, and the specific activity of the ΦPsa374 endolysin. Our study highlights an exciting opportunity for alternative antimicrobials in agriculture.
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Affiliation(s)
- Hazel M. Sisson
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Bioprotection Aotearoa, University of Otago, Dunedin, New Zealand
| | - Robert D. Fagerlund
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Bioprotection Aotearoa, University of Otago, Dunedin, New Zealand
- Genetics Otago, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Otago, Dunedin, New Zealand
| | - Simon A. Jackson
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Bioprotection Aotearoa, University of Otago, Dunedin, New Zealand
- Genetics Otago, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Otago, Dunedin, New Zealand
| | - Yves Briers
- Laboratory of Applied Biotechnology, Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Suzanne L. Warring
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Peter C. Fineran
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Bioprotection Aotearoa, University of Otago, Dunedin, New Zealand
- Genetics Otago, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Otago, Dunedin, New Zealand
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Sieiro C, Areal-Hermida L, Pichardo-Gallardo Á, Almuiña-González R, de Miguel T, Sánchez S, Sánchez-Pérez Á, Villa TG. A Hundred Years of Bacteriophages: Can Phages Replace Antibiotics in Agriculture and Aquaculture? Antibiotics (Basel) 2020; 9:E493. [PMID: 32784768 PMCID: PMC7460141 DOI: 10.3390/antibiotics9080493] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 08/04/2020] [Accepted: 08/04/2020] [Indexed: 12/12/2022] Open
Abstract
Agriculture, together with aquaculture, supplies most of the foodstuffs required by the world human population to survive. Hence, bacterial diseases affecting either agricultural crops, fish, or shellfish not only cause large economic losses to producers but can even create food shortages, resulting in malnutrition, or even famine, in vulnerable populations. Years of antibiotic use in the prevention and the treatment of these infections have greatly contributed to the emergence and the proliferation of multidrug-resistant bacteria. This review addresses the urgent need for alternative strategies for the use of antibiotics, focusing on the use of bacteriophages (phages) as biocontrol agents. Phages are viruses that specifically infect bacteria; they are highly host-specific and represent an environmentally-friendly alternative to antibiotics to control and kill pathogenic bacteria. The information evaluated here highlights the effectiveness of phages in the control of numerous major pathogens that affect both agriculture and aquaculture, with special emphasis on scientific and technological aspects still requiring further development to establish phagotherapy as a real universal alternative to antibiotic treatment.
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Affiliation(s)
- Carmen Sieiro
- Department of Functional Biology and Health Sciences, Microbiology Area, University of Vigo, Lagoas-Marcosende, 36310 Vigo, Spain; (L.A.-H.); (Á.P.-G.); (R.A.-G.)
| | - Lara Areal-Hermida
- Department of Functional Biology and Health Sciences, Microbiology Area, University of Vigo, Lagoas-Marcosende, 36310 Vigo, Spain; (L.A.-H.); (Á.P.-G.); (R.A.-G.)
| | - Ángeles Pichardo-Gallardo
- Department of Functional Biology and Health Sciences, Microbiology Area, University of Vigo, Lagoas-Marcosende, 36310 Vigo, Spain; (L.A.-H.); (Á.P.-G.); (R.A.-G.)
| | - Raquel Almuiña-González
- Department of Functional Biology and Health Sciences, Microbiology Area, University of Vigo, Lagoas-Marcosende, 36310 Vigo, Spain; (L.A.-H.); (Á.P.-G.); (R.A.-G.)
| | - Trinidad de Miguel
- Department of Microbiology and Parasitology, University of Santiago de Compostela, 5706 Santiago de Compostela, Spain; (T.d.M.); (S.S.)
| | - Sandra Sánchez
- Department of Microbiology and Parasitology, University of Santiago de Compostela, 5706 Santiago de Compostela, Spain; (T.d.M.); (S.S.)
| | - Ángeles Sánchez-Pérez
- Sydney School of Veterinary Science, Faculty of Science, University of Sydney, Sydnay NSN 2006, Australia;
| | - Tomás G. Villa
- Department of Microbiology and Parasitology, University of Santiago de Compostela, 5706 Santiago de Compostela, Spain; (T.d.M.); (S.S.)
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Stößer R, Scholz G, Möckel K, Backhaus E. Structural and dynamic aspects of the paramagnetic Cu(II)methylpyrazole complexes. J Mol Struct 1994. [DOI: 10.1016/0022-2860(93)07960-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Chakrabarti C, Chakrabarti T. Effects of irrigation with raw and differentially diluted sewage and application of primary settled sewage-sludge on wheat plant growth, crop yield, enxymatic changes and trace element uptake. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 1988; 51:219-235. [PMID: 15092628 DOI: 10.1016/0269-7491(88)90263-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/1987] [Revised: 10/28/1987] [Accepted: 11/03/1987] [Indexed: 05/24/2023]
Abstract
An increase in the concentration of Cu, Zn, Cr and Mn, and a decrease in the activities of aspartate amino transferase, alanine amino transferase and peroxidase were observed in the different fractions of wheat plants, following raw and differentially diluted (66% and 50%) sewage irrigation and dry primary settled sewage-sludge amendments of soils. The grain enrichment efficiencies for Cu, Zn and Mn were significantly low under all experimental conditions. On the other hand, the grain enrichment efficiency for Cr was low under all sewage irrigation conditions only. Except in the earheads of wheat plants from sludge-amended soil, catalase activities were significantly low in roots, stems and earheads of wheat plants, under all other treatment conditions investigated. The decrease in the proteinase activity was statistically significant in roots and earheads of sewage-irrigated plants; the activity in the stem was low following irrigation with raw and 66% sewage only. Proteinase activity was also significantly low in all fractions of wheat plants harvested from soil amended with 20 tonnes of sludge per hectare. The observed results appear to be due to an overall decrease in the metabolic status of the plants following sewage irrigation and sludge amendment of soils. Grain yields, however, were not reduced despite this metabolic effect.
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Affiliation(s)
- C Chakrabarti
- National Environmental Engineering Research Institute, Nehru Marg, Nagpur-440020, India
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Dave G. Effects of copper on growth, reproduction, survival and haemoglobin in Daphnia magna. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. C, COMPARATIVE PHARMACOLOGY AND TOXICOLOGY 1984; 78:439-43. [PMID: 6149094 DOI: 10.1016/0742-8413(84)90112-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The effects of additions of CuSO4 X 5H2O to final concentrations between 0.0004 and 105 micrograms Cu l-1 on growth, reproduction, survival and haemoglobin content of Daphnia magna were studied in hard reconstituted water and compared to the response in the dilution water without addition of copper. Concentrations of copper are nominal values. The 48-hr EC50 (immobilization) for unfed neonates was 6.5 micrograms Cu l-1 and the 48-hr and 21-day LC50 for fed neonates were 18.5 and 1.4 microgram Cu l-1, respectively. Growth expressed as body length of juveniles after 7 days and adult females after 21 days was only reduced in survivors at the highest non-lethal concentration (6.6 micrograms Cu l-1). Reproduction was stimulated by low concentrations of copper. Optimal reproduction after 21 days was found between 0.001 and 0.1 microgram Cu l-1. Higher concentrations were partially inhibitory (0.4 microgram Cu l-1), stimulatory (0.8 and 1.6 microgram Cu l-1) or completely inhibitory (3.2 micrograms Cu l-1 and above). The stimulatory peak around 1 microgram Cu l-1 was accompanied by a reduced survival (above 0.4 microgram Cu l-1). The Zero Equivalent Point (ZEP) for reproduction at non-reduced survival was 0.23 microgram Cu l-1. This concentration should be "safe" for D. magna under prevailing conditions (reconstituted water with a hardness of 250 mg l-1 as CaCo3 and a synthetic diet based on fish food and baby gruel). The haemoglobin content was affected by copper in a complex pattern which was not related to growth, reproduction or survival.
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