Packaging of Live
            <i>Legionella pneumophila</i>
            into Pellets Expelled by
            <i>Tetrahymena</i>
            spp. Does Not Require Bacterial Replication and Depends on a Dot/Icm-Mediated Survival Mechanism

Berk, Sharon G.; Faulkner, Gary; Garduño, Elizabeth; Joy, Mark C.; Ortiz-Jiménez, Marco A.; Garduño, Rafael A.

doi:10.1128/aem.01214-07

Cited by 88 publications

(117 citation statements)

References 49 publications

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“…All strains were cultivated axenically (that is, growth on dissolved nutrients only without bacteria as food source) to avoid transfer of bacteria to the experiments. Protist cultures were grown in the respective media, concentrated by centrifugation 52,53 and washed with Brunner CR-2 medium before using them for the experiments. The overall total initial densities of protists were kept equal (5 Â 10 4 cells) in all predator treatments.…”

Section: Methodsmentioning

confidence: 99%

Predator richness increases the effect of prey diversity on prey yield

et al. 2012

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Positive biodiversity-ecosystem functioning relationships are generally attributed to two mechanisms: complementarity and selection. These mechanisms have been primarily examined using plant communities, whereas bacterial communities remain largely unexplored. Moreover, it remains uncertain how predation by single or multiple predators affects these mechanisms. Here using 465 bacterial microcosms, we show that multiple predation by protists results in positive bacterial diversity effects on bacterial yields (colonyforming units) possibly due to an increased complementarity and evenness among bacterial species. By mathematically partitioning the biodiversity effects, we demonstrate that competitive interactions in diverse communities are reduced and the growth of subdominant species is enhanced. We envisage that, including diversity gradients at other trophic levels, in biodiversity-ecosystem functioning research is a key to understanding and managing ecosystem processes. Such level of manipulation can be achieved best in microbial model systems, which are powerful tools for fundamental hypothesis-driven experiments and the investigation of general ecological theories.

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Section: Methodsmentioning

confidence: 99%

Predator richness increases the effect of prey diversity on prey yield

et al. 2012

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“…In addition, in some cases, the microbes during their stay in the phagocytic vesicles can be transformed to more pathogenic 284 CSABA and hypervirulent forms [73]. In this case, the packaging of bacteria by the protozoan vesicles is the Trojan Horse, which transports the disease [70]. Considering this fact, the bacterium has the advantage because of propagating itself.…”

Section: Discussionmentioning

confidence: 99%

“…This is why Tetrahymena infection is very dangerous to many fish species [69]. However, not only fishes but also mammals, including human, are touched by different infections, as by a similar way, the L. pneumophila [70,71] and Salmonella enterica [72], causing diseases, are transported. In addition, in some cases, the microbes during their stay in the phagocytic vesicles can be transformed to more pathogenic 284 CSABA and hypervirulent forms [73].…”

Section: Discussionmentioning

confidence: 99%

Lectins and Tetrahymena – A review

Csaba

2016

Acta Microbiologica et Immunologica Hungarica

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The unicellular ciliate Tetrahymena is a complete organism, one of the most highly developed protozoans, which has specialized organelles performing each of the functions characteristic to the cells of higher ranked animals. It is also able to produce, store, and secrete hormones of higher ranked animals and also react to them. It produces lectins that can bind them and has functions, which are influenced by exogenous lectins. The review lists the observations on the relationship between lectins and Tetrahymena and try to construe them on the basis of the data, which are at our disposal. Considering the data, lectins can be used by Tetrahymena as materials for influencing conjugation, for stimulating hormone receptors, and by this, mimic the hormonal functions. Lectins can influence phagocytosis and movement of the cells as well as the cell division. As Tetrahymena can recognize both related and hostile cells by the help of lectins and surface sugars, it could be surmised a complex predator-prey system. This could determine the survival of the population as well as the nourishment conditions. When Tetrahymena is pathogenic, it can use lectins as virulence factors.

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“…As a comparison, the residence times of E. coli and L. pneumophila in Tetrahymena were reported to be approximately 2 to 4 h (47,53,55). It is known that the food vacuoles in ciliates can take as little as 1 h to proceed from ingestion to exocytosis (56).…”

Section: Discussionmentioning

confidence: 99%

Packaging of Campylobacter jejuni into Multilamellar Bodies by the Ciliate Tetrahymena pyriformis

Trigui

Paquet

Charette

et al. 2016

Appl Environ Microbiol

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dCampylobacter jejuni is the leading cause of bacterial gastroenteritis worldwide. Transmission to humans occurs through consumption of contaminated food or water. The conditions affecting the persistence of C. jejuni in the environment are poorly understood. Some protozoa package and excrete bacteria into multilamellar bodies (MLBs). Packaged bacteria are protected from deleterious conditions, which increases their survival. We hypothesized that C. jejuni could be packaged under aerobic conditions by the amoeba Acanthamoeba castellanii or the ciliate Tetrahymena pyriformis, both of which are able to package other pathogenic bacteria. A. castellanii did not produce MLBs containing C. jejuni. In contrast, when incubated with T. pyriformis, C. jejuni was ingested, packaged in MLBs, and then expelled into the milieu. The viability of the bacteria inside MLBs was confirmed by microscopic analyses. The kinetics of C. jejuni culturability showed that packaging increased the survival of C. jejuni up to 60 h, in contrast to the strong survival defect seen in ciliate-free culture. This study suggests that T. pyriformis may increase the risk of persistence of C. jejuni in the environment and its possible transmission between different reservoirs in food and potable water through packaging. Campylobacter jejuni is a leading cause of human gastroenteritis worldwide and a major public health problem (1-3). Severe symptoms of C. jejuni infection include high fever, watery to bloody diarrhea, nausea, and vomiting (4). In severe cases, C. jejuni is associated with serious postinfectious complications, such as Guillain-Barré syndrome (5, 6).Despite causing a serious disease in humans, C. jejuni is usually viewed as commensal in chickens (7) and livestock animals such as cattle (8) and pigs (9). Once these animals are colonized with Campylobacter spp., they excrete large numbers of the microorganisms in their feces and commonly contaminate different aquatic habitats, such as surface waters close to farming activities, agricultural runoff, wastewater effluent, sewage, and marine environments (10). Numerous epidemiological studies have demonstrated that water is not only a significant reservoir of C. jejuni but also an important factor for the spread of C. jejuni in farms, throughout flocks, and in slaughterhouses (11-15).C. jejuni requires a microaerobic environment (80% N 2 , 10% CO 2 , 5% H 2 , and 5% O 2 ) (16) and a narrow range of temperatures (37 to 43°C) for optimal growth (17). Because of the constraints imposed by its sensitivity to oxygen, C. jejuni is considered less able to tolerate environmental stress than other foodborne pathogens (18). Once outside the host, however, the interaction of C. jejuni with other microorganisms could help it survive high concentrations of oxygen and other environmental stresses.Since the study by Snelling et al. (19), in which Campylobacter and protozoa were isolated from the same broiler drinking water systems, the potential interactions between these microorganisms have been investigate...

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Packaging of Live Legionella pneumophila into Pellets Expelled by Tetrahymena spp. Does Not Require Bacterial Replication and Depends on a Dot/Icm-Mediated Survival Mechanism

Cited by 88 publications

References 49 publications

Predator richness increases the effect of prey diversity on prey yield

Predator richness increases the effect of prey diversity on prey yield

Lectins and Tetrahymena – A review

Packaging of Campylobacter jejuni into Multilamellar Bodies by the Ciliate Tetrahymena pyriformis

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