GROWTH OF
            <i>ACANTHAMOEBA CASTELLANI</i>
            WITH THE YEAST
            <i>TORULOPSIS FAMATA</i>

Nero, Luke; Tarver, Mae G.; Hedrick, L. R.

doi:10.1128/jb.87.1.220-225.1964

Cited by 16 publications

(8 citation statements)

References 1 publication

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“…[21], providing an early report of fungal–amoeba interactions whereby the amoeba appear to lyse the yeast cells. In 1955, A. castellanii was shown to feed on C. neoformans [22] and subsequently demonstrated to feed on cultures of Torula famata and Candida parapsilosis [23]. Interestingly, this early study reported that growth on the yeast C. parapsilosis was much faster than growth on the filamentous T. famata since the protozoa had difficulty ingesting hyphae [23].…”

Section: Early Studies On the Interaction Of Fungi And Amoebamentioning

confidence: 99%

“…In 1955, A. castellanii was shown to feed on C. neoformans [22] and subsequently demonstrated to feed on cultures of Torula famata and Candida parapsilosis [23]. Interestingly, this early study reported that growth on the yeast C. parapsilosis was much faster than growth on the filamentous T. famata since the protozoa had difficulty ingesting hyphae [23]. Beginning in the late 1970s, Bulmer and colleagues carried out studies of the interaction of C. neoformans with amoeba and established that the protozoa preyed and devoured encapsulated cells with the emergence of hyphal cells as resistant forms, which were hypovirulent in mice [24,25].…”

Section: Early Studies On the Interaction Of Fungi And Amoebamentioning

confidence: 99%

“…An emerging theme in amoeba-fungal studies is that hyphal forms are more resistant to protozoal predation than yeast forms. This was noted as early as 1964 when Nero et al reported that a mold was more resistant to amoeba than Candida parapsilosis [23]. Similarly, Bulmer et al noted amoeba predation of C. neoformans lawns resulted in the emergence of pseudohyphal forms, which were resistant to amoeba but less virulent in mice [25].…”

Section: Amoeba and Fungal Dimorphismmentioning

confidence: 99%

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The ‘Amoeboid Predator-Fungal Animal Virulence’ Hypothesis

Casadevall

Guimarães

et al. 2019

JoF

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The observation that some aspects of amoeba-fungal interactions resemble animal phagocytic cell-fungal interactions, together with the finding that amoeba passage can enhance the virulence of some pathogenic fungi, has stimulated interest in the amoeba as a model system for the study of fungal virulence. Amoeba provide a relatively easy and cheap model system where multiple variables can be controlled for the study of fungi-protozoal (amoeba) interactions. Consequently, there have been significant efforts to study fungal–amoeba interactions in the laboratory, which have already provided new insights into the origin of fungal virulence as well as suggested new avenues for experimentation. In this essay we review the available literature, which highlights the varied nature of amoeba-fungal interactions and suggests some unsolved questions that are potential areas for future investigation. Overall, results from multiple independent groups support the ‘amoeboid predator–fungal animal virulence hypothesis’, which posits that fungal cell predation by amoeba can select for traits that also function during animal infection to promote their survival and thus contribute to virulence.

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Section: Early Studies On the Interaction Of Fungi And Amoebamentioning

confidence: 99%

Section: Early Studies On the Interaction Of Fungi And Amoebamentioning

confidence: 99%

Section: Amoeba and Fungal Dimorphismmentioning

confidence: 99%

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The ‘Amoeboid Predator-Fungal Animal Virulence’ Hypothesis

Casadevall

Guimarães

et al. 2019

JoF

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“…All 19 species of yeasts were eaten by at least two of the amoebae and all four species of amoebae grew well on several of the yeasts. Nero et al [85] found Acanthamoeba castellanii to grow well on the yeast Torulopsis famata.…”

Section: Phagotrophic Feedingmentioning

confidence: 99%

Notes on protozoa in agricultural soil with emphasis on heterotrophic flagellates and naked amoebae and their ecology

Rønn

1994

FEMS Microbiology Reviews

220

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Heterotrophic flagellates and naked amoebae are usually very numerous in agricultural soils; with numbers in the magnitude of 10,000 to 100,000 (active+encysted) cells per gram of soil. In 'hotspots' influenced by living roots or by dead organic material, the number may occasionally be as high as several millions per gram of soil. An exact enumeration of these organisms is virtually impossible. As they most often adhere closely to the soil particles, direct counting will underestimate numbers since the organisms will be masked. The method usually applied for enumeration of these organisms, the 'most probable number (MPN) method', is based on the ability of the organisms to grow on particular culture media. This method will in many cases underestimate the total protozoan number (active+encysted). It is uncertain how many of the heterotrophic flagellates and naked amoebae are actively moving and how many are encysted at a particular time; the 'HCl-method' which has usually been used to discriminate between active and encysted has proven to be highly unreliable. Despite the methodological difficulties many investigations of these organisms indicate that they play an important role in agricultural soils as bacterial consumers, and to a minor extent as consumers of fungi. Because of their small size and their flexible body they are able to graze bacteria in small pores in the soil in which larger organisms are precluded from coming. Key factors restricting the number and activity of heterotrophic flagellates and naked amoebae in soils seem to be water potential and soil structure and texture. In micro-cosm experiments, small heterotrophic flagellates and naked amoebae regulate the size and composition of the bacterial community. Bacterial activity seems to be stimulated by these organisms in most cases as well as the mineralization of carbon and nitrogen and possibly other mineral nutrients. In the rhizosphere of living plants the activity of protozoa has proven to stimulate uptake of nitrogen in pot experiments, and it has been hypothesized that organic matter liberated by plants in the root zone will stimulate bacterial and protozoan activity, leading to mineralization of organic soil nitrogen which is subsequently taken up by the plants.

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“…Various bacteria can serve as nutrients for amoebae. The soil amoebae, Acanthamoeba castellani and Acanthamoeba sp., have been shown to grow on both bacteria and yeasts (9,10,11). Chang (4) demonstrated that gram-negative bacilli were utilized by a strain of H. glebae and gram-positive bacilli were not utilized by this organism.…”

Section: Discussionmentioning

confidence: 99%

Growth and Bacteriolytic Activity of a Soil Amoeba, Hartmannella glebae

Upadhyay

1968

J Bacteriol

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A soil amoeba, Hartmannella glebae, could grow on a variety of gram-positive and gram-negative bacteria, although the rate of growth was faster in the presence of gram-negative bacteria. The amoeba, however, could not use yeasts, molds, or a green alga as a nutritional source. The extract prepared from amoebae grown in the presence of Aerobacter aerogenes and Alcaligenes faecalis could lyse intact cells and cell walls of many gram-positive bacteria at different rates. The spectrum of lytic activity was similar to that of egg-white lysozyme, with the exception that several species and strains of Bacillus, Micrococcus, and Staphylococcus were resistant to lysozyme and susceptible to the extract. The gram-negative bacteria tested were resistant.

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GROWTH OF ACANTHAMOEBA CASTELLANI WITH THE YEAST TORULOPSIS FAMATA

Abstract: Acanthamoeba castellani and Torulopsis famata cells were cultured together for 10 days at three different temperatures: 18, 25, and 32 C. In

Cited by 16 publications

References 1 publication

The ‘Amoeboid Predator-Fungal Animal Virulence’ Hypothesis

The ‘Amoeboid Predator-Fungal Animal Virulence’ Hypothesis

Notes on protozoa in agricultural soil with emphasis on heterotrophic flagellates and naked amoebae and their ecology

Growth and Bacteriolytic Activity of a Soil Amoeba, Hartmannella glebae

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