Cultivation of Pathogenic and Opportunistic Free-Living Amebas

Schuster, Frederick L.

doi:10.1128/cmr.15.3.342-354.2002

Cited by 332 publications

(247 citation statements)

References 68 publications

Supporting

Mentioning

225

Contrasting

Unclassified

Order By: Relevance

“…An axenic culture was established by using PGY medium (1% peptone, 1% glucose, 0.5% yeast-extract) containing the antibiotics streptomycin (10 mg ml À1 final concentration) and gentamycin (15 mg ml À1 final concentration) as described by Schuster (2002). The A. castellanii culture was repeatedly diluted with PGY antibiotic solution every day for 1 week and subsequently incubated 1 further week in PGY gentamycin solution until the cultures were bacteria free.…”

Section: Plant Performancementioning

confidence: 99%

Soil amoebae rapidly change bacterial community composition in the rhizosphere of Arabidopsis thaliana

Rosenberg¹,

Bertaux²,

Krome³

et al. 2009

The ISME Journal

216

183

View full text Add to dashboard Cite

We constructed an experimental model system to study the effects of grazing by a common soil amoeba, Acanthamoeba castellanii, on the composition of bacterial communities in the rhizosphere of Arabidopsis thaliana. Amoebae showed distinct grazing preferences for specific bacterial taxa, which were rapidly replaced by grazing tolerant taxa in a highly reproducible way. The relative proportion of active bacteria increased although bacterial abundance was strongly decreased by amoebae. Specific bacterial taxa had disappeared already two days after inoculation of amoebae. The decrease in numbers was most pronounced in Betaproteobacteria and Firmicutes. In contrast, Actinobacteria, Nitrospira, Verrucomicrobia and Planctomycetes increased. Although other groups, such as betaproteobacterial ammonia oxidizers and Gammaproteobacteria did not change in abundance, denaturing gradient gel electrophoresis with specific primers for pseudomonads (Gammaproteobacteria) revealed both specific changes in community composition as well as shifts in functional genes (gacA) involved in bacterial defence responses. The resulting positive feedback on plant growth in the amoeba treatment confirms that bacterial grazers play a dominant role in structuring bacteria-plant interactions. This is the first detailed study documenting how rapidly protozoan grazers induce shifts in rhizosphere bacterial community composition.

show abstract

Section: Plant Performancementioning

confidence: 99%

Soil amoebae rapidly change bacterial community composition in the rhizosphere of Arabidopsis thaliana

Rosenberg¹,

Bertaux²,

Krome³

et al. 2009

The ISME Journal

216

183

View full text Add to dashboard Cite

show abstract

“…A. castellanii ATCC 30234 was cultured axenically in peptone-yeast extract-glucose (PYG) medium (26). Cultures were incubated in flask at 25°C for 72 h leading to ca.…”

Section: Methodsmentioning

confidence: 99%

Cellular Response of the Amoeba Acanthamoeba castellanii to Chlorine, Chlorine Dioxide, and Monochloramine Treatments

Mogoa

Bodet

Morel

et al. 2011

Appl Environ Microbiol

View full text Add to dashboard Cite

Acanthamoeba castellanii is a free-living amoebae commonly found in water systems. Free-living amoebae might be pathogenic but are also known to bear phagocytosis-resistant bacteria, protecting these bacteria from water treatments. The mode of action of these treatments is poorly understood, particularly on amoebae. It is important to examine the action of these treatments on amoebae in order to improve them. The cellular response to chlorine, chlorine dioxide, and monochloramine was tested on A. castellanii trophozoites. Doses of disinfectants leading to up to a 3-log reduction were compared by flow cytometry and electron microscopy. Chlorine treatment led to size reduction, permeabilization, and retraction of pseudopods. In addition, treatment with chlorine dioxide led to a vacuolization of the cytoplasm. Monochloramine had a dose-dependent effect. At the highest doses monochloramine treatment resulted in almost no changes in cell size and permeability, as shown by flow cytometry, but the cell surface became smooth and dense, as seen by electron microscopy. We show that these disinfectants globally induced size reduction, membrane permeabilization, and morphological modifications but that they have a different mode of action on A. castellanii.

show abstract

“…Previous studies have successfully made use of African green monkey kidney cells to isolate B. mandrillaris from brain tissues (Schuster, 2002). However, primary HBMECs are physiologically most relevant in the actual infection as these cells constitute the blood-brain barrier.…”

Section: Discussionmentioning

confidence: 99%

“…Both the brain necropsy and the CSF specimens were inoculated on HBMEC monolayers in tissue culture flasks. Flasks were incubated at 37 8C in a 5 % CO 2 incubator and observed daily for the presence of B. mandrillaris as previously described (Schuster, 2002).…”

Section: Methodsmentioning

confidence: 99%

Post-mortem culture of Balamuthia mandrillaris from the brain and cerebrospinal fluid of a case of granulomatous amoebic meningoencephalitis, using human brain microvascular endothelial cells

Jayasekera

Sissons

Tucker

et al. 2004

Journal of Medical Microbiology

View full text Add to dashboard Cite

The first isolation in the UK of Balamuthia mandrillaris amoebae from a fatal case of granulomatous amoebic meningoencephalitis is reported. Using primary cultures of human brain microvascular endothelial cells (HBMECs), amoebae were isolated from the brain and cerebrospinal fluid (CSF). The cultures showed a cytopathic effect at 20-28 days, but morphologically identifiable B. mandrillaris amoebae were seen in cleared plaques in subcultures at 45 days. The identification of the organism was later confirmed using PCR on Chelex-treated extracts. Serum taken while the patient was still alive reacted strongly with slide antigen prepared from cultures of the post-mortem isolate, and also with those from a baboon B. mandrillaris strain at 1 : 10 000 in indirect immunofluorescence, but with Acanthamoeba castellanii (Neff) at 1 : 160, supporting B. mandrillaris to be the causative agent. If the presence of amoebae in the post-mortem CSF reflects the condition in life, PCR studies on CSF and on biopsies of cutaneous lesions may also be a valuable tool. The role of HBMECs in understanding the interactions of B. mandrillaris with the blood-brain barrier is discussed.

show abstract

Cultivation of Pathogenic and Opportunistic Free-Living Amebas

Cited by 332 publications

References 68 publications

Soil amoebae rapidly change bacterial community composition in the rhizosphere of Arabidopsis thaliana

Soil amoebae rapidly change bacterial community composition in the rhizosphere of Arabidopsis thaliana

Cellular Response of the Amoeba Acanthamoeba castellanii to Chlorine, Chlorine Dioxide, and Monochloramine Treatments

Post-mortem culture of Balamuthia mandrillaris from the brain and cerebrospinal fluid of a case of granulomatous amoebic meningoencephalitis, using human brain microvascular endothelial cells

Contact Info

Product

Resources

About