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Farthing HN, Jiang J, Henwood AJ, Fenton A, Garner TWJ, Daversa DR, Fisher MC, Montagnes DJS. Microbial Grazers May Aid in Controlling Infections Caused by the Aquatic Zoosporic Fungus Batrachochytrium dendrobatidis. Front Microbiol 2021; 11:592286. [PMID: 33552011 PMCID: PMC7858660 DOI: 10.3389/fmicb.2020.592286] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 12/16/2020] [Indexed: 11/13/2022] Open
Abstract
Free-living eukaryotic microbes may reduce animal diseases. We evaluated the dynamics by which micrograzers (primarily protozoa) apply top-down control on the chytrid Batrachochytrium dendrobatidis (Bd) a devastating, panzootic pathogen of amphibians. Although micrograzers consumed zoospores (∼3 μm), the dispersal stage of chytrids, not all species grew monoxenically on zoospores. However, the ubiquitous ciliate Tetrahymena pyriformis, which likely co-occurs with Bd, grew at near its maximum rate (r = 1.7 d-1). A functional response (ingestion vs. prey abundance) for T. pyriformis, measured using spore-surrogates (microspheres) revealed maximum ingestion (I max ) of 1.63 × 103 zoospores d-1, with a half saturation constant (k) of 5.75 × 103 zoospores ml-1. Using these growth and grazing data we developed and assessed a population model that incorporated chytrid-host and micrograzer dynamics. Simulations using our data and realistic parameters obtained from the literature suggested that micrograzers could control Bd and potentially prevent chytridiomycosis (defined as 104 sporangia host-1). However, simulated inferior micrograzers (0.7 × I max and 1.5 × k) did not prevent chytridiomycosis, although they ultimately reduced pathogen abundance to below levels resulting in disease. These findings indicate how micrograzer responses can be applied when modeling disease dynamics for Bd and other zoosporic fungi.
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Affiliation(s)
- Hazel N. Farthing
- Shanghai Universities Key Laboratory of Marine Animal Taxonomy and Evolution, Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
- Department of Evolution, Ecology and Behaviour, Biosciences Building, University of Liverpool, Liverpool, United Kingdom
| | - Jiamei Jiang
- Shanghai Universities Key Laboratory of Marine Animal Taxonomy and Evolution, Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, China
| | - Alexandra J. Henwood
- Department of Evolution, Ecology and Behaviour, Biosciences Building, University of Liverpool, Liverpool, United Kingdom
| | - Andy Fenton
- Department of Evolution, Ecology and Behaviour, Biosciences Building, University of Liverpool, Liverpool, United Kingdom
| | - Trent W. J. Garner
- Institute of Zoology, Zoological Society of London, London, United Kingdom
| | - David R. Daversa
- MRC Centre for Global Infectious Disease Analysis, Imperial College London, London, United Kingdom
| | - Matthew C. Fisher
- Department of Evolution, Ecology and Behaviour, Biosciences Building, University of Liverpool, Liverpool, United Kingdom
- Institute of Zoology, Zoological Society of London, London, United Kingdom
| | - David J. S. Montagnes
- Department of Evolution, Ecology and Behaviour, Biosciences Building, University of Liverpool, Liverpool, United Kingdom
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Yang J, Wei H, Yalin T, Alan W, Xiaofeng L, Jiqiu L. Combined effects of food resources and exposure to ammonium nitrogen on population growth performance in the bacterivorous ciliate Paramecium caudatum. Eur J Protistol 2019; 71:125631. [PMID: 31542654 DOI: 10.1016/j.ejop.2019.125631] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 06/11/2019] [Accepted: 06/12/2019] [Indexed: 10/26/2022]
Abstract
Ciliated protozoa (ciliates) play vital roles in biological wastewater-treatment processes, however, combined effects of abiotic and biotic factors as well as the importance of species-specificity of bacterial food organisms on population growth dynamics remain poorly understood, which are hampering the management and optimization of biological wastewater treatment processes. This study investigated the effects of food resources and ammonium nitrogen (NH4+) exposure, both independently and in combination, on the population growth of the bacterivorous ciliate Paramecium caudatum. Results showed that, when fed with two different bacterial food organisms, population growth performance of P. caudatum differed significantly and increased with the addition of protozoa pellet medium. When exposed to NH4+ population growth declined and metabolic enzyme activities were altered. The negative effects of NH4+ on population growth could be weakened by supplementing the food resource with protozoa pellet media. In brief, it was confirmed that the existence of interactive effect of food resources and ammonium nitrogen, as well as the importance of species-specificity of bacterial food organisms on the population growth performance of ciliates. These findings might lead to the development of a valuable strategy for improving the performance of biological wastewater-treatment processes.
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Affiliation(s)
- Jing Yang
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, South China Normal University, Guangzhou 510631, PR China
| | - Hu Wei
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, South China Normal University, Guangzhou 510631, PR China
| | - Tan Yalin
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, South China Normal University, Guangzhou 510631, PR China
| | - Warren Alan
- Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Lin Xiaofeng
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, South China Normal University, Guangzhou 510631, PR China
| | - Li Jiqiu
- Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, South China Normal University, Guangzhou 510631, PR China.
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O'Malley MA, Parke EC. Microbes, mathematics, and models. STUDIES IN HISTORY AND PHILOSOPHY OF SCIENCE 2018; 72:1-10. [PMID: 30497583 DOI: 10.1016/j.shpsa.2018.07.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 01/22/2018] [Accepted: 07/12/2018] [Indexed: 06/09/2023]
Abstract
Microbial model systems have a long history of fruitful use in fields that include evolution and ecology. In order to develop further insight into modelling practice, we examine how the competitive exclusion and coexistence of competing species have been modelled mathematically and materially over the course of a long research history. In particular, we investigate how microbial models of these dynamics interact with mathematical or computational models of the same phenomena. Our cases illuminate the ways in which microbial systems and equations work as models, and what happens when they generate inconsistent findings about shared targets. We reveal an iterative strategy of comparative modelling in different media, and suggest reasons why microbial models have a special degree of epistemic tractability in multimodel inquiry.
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Affiliation(s)
- Maureen A O'Malley
- University of Bordeaux, France; University of Sydney, HPS, Carslaw Building, NSW, 2006, Australia.
| | - Emily C Parke
- University of Auckland, Philosophy, School of Humanities, Room 538, Level 5, 14A Symonds St, Auckland, 1010, New Zealand.
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Miura T, Moriya H, Iwai S. Assessing phagotrophy in the mixotrophic ciliate Paramecium bursaria using GFP-expressing yeast cells. FEMS Microbiol Lett 2017; 364:3861962. [DOI: 10.1093/femsle/fnx117] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 06/06/2017] [Indexed: 12/13/2022] Open
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