Small Amebas and Ameboflagellates

Schuster, Frederickl

doi:10.1016/b978-0-12-444601-4.50015-1

Cited by 31 publications

(18 citation statements)

References 300 publications

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“…This observation was supported by reports that Acanthamoeba spp. expel food vacuoles prior to encystment rather than retaining them within the cyst (18,19). We also observed vesicles expelled from amoebas in the present study (data not shown).…”

supporting

confidence: 74%

Temperature-Dependent Parasitic Relationship between Legionella pneumophila and a Free-Living Amoeba ( Acanthamoeba castellanii )

Ohno¹,

Kato

Sakamoto

et al. 2008

Appl Environ Microbiol

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We analyzed the effects of temperature on the interaction of Legionella pneumophila with Acanthamoeba castellanii. At <20°C, overexpression of type 1 metacaspase, a stimulator of A. castellanii encystation, was associated with a reduced number of bacteria within amoeba. At low temperatures, A. castellanii seems to eliminate L. pneumophila by encystation and digestion.The intracellular pathogen Legionella pneumophila causes Legionnaires' disease and exploits aquatic protozoa for replication. L. pneumophila is more frequently isolated from man-made water systems with high water temperature (9, 17) than from relatively cold freshwater environments (4,16). This fact suggests that thermal conditions affect the relationship between L. pneumophila and protozoa, a notion supported by some reports (1, 3, 7, 11). The trophozoite of protozoa transforms into a cyst under harmful environments such as starvation, cold, and certain chemicals used in medical treatment. The effect of protozoal encystation on Legionella infection is not well understood although it seems that encystation is enhanced in a freshwater environment at low temperature. With these considerations in mind, we investigated whether the host-parasite relationship between L. pneumophila and protozoa is temperature dependent.Two strains of L. pneumophila serogroup 1, Suzuki and Lp01, and Acanthamoeba castellanii ATCC 30234 were used in the present study. Intracellular growth kinetics assays using A. castellanii were performed as described previously (15 Total RNA was purified using an RNeasy minikit (Qiagen, Valencia, CA) according to the instructions provided by the manufacturer. Total RNA was reverse transcribed into cDNA using an RNA PCR kit (Takara Bio Inc., Shiga, Japan). Real-time PCR with Sybr greenER (Invitrogen Life Sciences) was performed using the ABI Prism 7000 system (Applied Biosystems, Foster City, CA). Table 1 lists the primer pairs for target and internal control genes. Data were analyzed by Student's t test, and a two-tailed P value of Ͻ0

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supporting

confidence: 74%

Temperature-Dependent Parasitic Relationship between Legionella pneumophila and a Free-Living Amoeba ( Acanthamoeba castellanii )

Ohno¹,

Kato

Sakamoto

et al. 2008

Appl Environ Microbiol

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“…Campylobacter survival to chemical disinfection with an iodine‐based product has been reported to increase when associated with A. castellanii and T. pyriformis trophozoites (Snelling et al , 2005). Encystment of FLA is preceded by the expulsion of food vacuoles and vesicles (Schuster, 1979). These vesicles can also contain intracellular bacteria that have been observed to stay viable for up to 6 months (Bouyer et al , 2007).…”

Section: Biocide Efficacy Against Intracellular Pathogensmentioning

confidence: 99%

Free-living amoebae and their intracellular pathogenic microorganisms: risks for water quality

Thomas¹,

McDonnell²,

et al. 2010

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An increasing number of microorganisms, including bacteria but also viruses and eukaryotes, have been described as benefiting from interaction with free-living amoebae (FLA). Beneficial interaction can be due to resistance to predation conferring ecological advantage, intracellular survival and/or intracellular proliferation. This review highlights the potential risk associated with amoebae by listing all known pathogenic microbial species for which growth and/or survival promotion by FLA (mainly Acanthamoeba spp.) has been demonstrated. It focuses on the susceptibility of amoebal and intra-amoebal bacteria to various categories of biocides, the known mechanisms of action of these biocides against trophozoites and cysts and the various methods used to demonstrate efficacy of treatments against FLA. Brief descriptions of FLA ecology and prevalence in domestic/institutional water systems and their intrinsic pathogenicity are also presented. The intention is to provide an informed opinion on the environmental risks associated with the presence of FLA and on the survival of cysts following biocidal treatments, while also highlighting the need to conduct research on the roles of amoebae in aquatic ecosystems.

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“…Cysts are the dormant stage of amoebae and form in the event of unfavorable conditions such as nutrient depletion and various physical and chemical stresses, including biocidal treatments. The encystment of amoebae is preceded by the expulsion of food vacuoles and vesicles (Schuster 1979). These vesicles may contain bacteria that are protected from the effect of biocides (Berk et al 1998).…”

Section: Pathogen Protection In Multispecies Biofilmsmentioning

confidence: 99%

Resistance of bacterial biofilms to disinfectants: a review

et al. 2011

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A biofilm can be defined as a community of microorganisms adhering to a surface and surrounded by a complex matrix of extrapolymeric substances. It is now generally accepted that the biofilm growth mode induces microbial resistance to disinfection that can lead to substantial economic and health concerns. Although the precise origin of such resistance remains unclear, different studies have shown that it is a multifactorial process involving the spatial organization of the biofilm. This review will discuss the mechanisms identified as playing a role in biofilm resistance to disinfectants, as well as novel anti-biofilm strategies that have recently been explored.

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Small Amebas and Ameboflagellates

Cited by 31 publications

References 300 publications

Temperature-Dependent Parasitic Relationship between Legionella pneumophila and a Free-Living Amoeba ( Acanthamoeba castellanii )

Temperature-Dependent Parasitic Relationship between Legionella pneumophila and a Free-Living Amoeba ( Acanthamoeba castellanii )

Free-living amoebae and their intracellular pathogenic microorganisms: risks for water quality

Resistance of bacterial biofilms to disinfectants: a review

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