scholarly journals Isolation and identification of 1(3),2-diacylglyceryl-(3)-O-4'-(N,N,N-trimethyl)homoserine from the soil amoeba, Acanthamoeba castellanii.

1990 ◽  
Vol 27 (11) ◽  
pp. 1182-1189
Author(s):  
S T Furlong ◽  
J A Leary ◽  
C E Costello ◽  
E A Dawidowicz
Keyword(s):  
Acanthamoeba Castellanii ◽  
Isolation And Identification ◽  
Soil Amoeba

scholarly journals Oxygen affinity of the respiratory chain of Acanthamoeba castellanii

1983 ◽  
Vol 214 (1) ◽  
pp. 47-51 ◽  
Author(s):  
D Lloyd ◽  
H Mellor ◽  
J L Williams
Keyword(s):  
Plasma Membrane ◽  
Cytochrome C ◽  
Cytochrome B ◽  
Respiratory Chain ◽  
Oxygen Affinity ◽  
Acanthamoeba Castellanii ◽  
Intact Cells ◽  
Cytochrome Aa3 ◽  
Isolated Mitochondria ◽  
Soil Amoeba

Apparent Km values for O2 for the soil amoeba Acanthamoeba castellanii determined polarographically and by bioluminescence gave similar values (0.37 and 0.41 microM respectively). Mitochondria oxidizing succinate or NADH in the presence or absence of ADP gave values in the range 0.21-0.36 microM-O2. Oxidation of respiratory-chain components to 50% of the aerobic steady states in intact cells was observed at the following O2 concentrations: cytochrome aa3, 0.1-0.25 microM; cytochrome c, 0.3-0.6 microM; cytochrome b, 0.35-0.45 microM; flavoprotein, 2 microM. In isolated mitochondria corresponding values for a-, c- and b-type cytochromes were 0.007, 0.035-0.05 and 0.06-0.09 microM-O2. It is concluded that an O2 gradient exists between plasma membrane and mitochondria in A. castellanii.

Ion composition of the contractile vacuole of Acanthamoeba castellanii as determined by x-ray microanalysis

1995 ◽  
Vol 53 ◽  
pp. 880-881
Author(s):  
B. Bowers ◽  
S.L. Shi ◽  
S.Q. Sun ◽  
R.D. Leapman
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Acanthamoeba Castellanii ◽  
Contractile Vacuole ◽  
X Ray ◽  
Water Pumping ◽  
Analytical Electron ◽  
Filling Phase ◽  
Soil Amoeba ◽  
Insight Into

The contractile vacuole (CV) is an osmoregulatory organelle found in free-living protozoa that functions to pump water out of the cell. In amoebae it comprises at least two distinct systems, a spongiome of tubules and/or vesicles that surround a central collecting vacuole (Fig 1). The filling phase and the discharge of the engorged vacuole appear to be independently regulated. Calmodulin, alkaline phosphatase ,and a proton pump are known to be specifically associated with the CV complex in amoebae, but the mechanism of water pumping is not known. In order to gain insight into possible ion transport mechanisms, we have examined the ion content of the CV of the small soil amoeba, Acanthamoeba castellanii, by analytical electron microscopy.For analytical electron microscopy amoebae were incubated in growth medium with 5% polyvinyl pyrrolidone (PVP), MW 360,000, for 1.5 hours, then concentrated by centrifugation and rapidly frozen by plunging into liquid nitrogen-cooled ethane. The frozen samples were cryosectioned and cryotransferred at -180° C into a VGHB501 STEM equipped with a Gatan parallel energy loss spectrometer (EELS) and a Noran energy dispersive X-ray spectrometer (EDXS).

scholarly journals Carbon monoxide- and oxygen-reacting haemoproteins in the mitochondrial fraction from the soil amoeba Acanthamoeba castellanii. Studies at subzero temperatures

1981 ◽  
Vol 200 (2) ◽  
pp. 337-342 ◽  
Author(s):  
D Lloyd ◽  
S W Edwards ◽  
B Chance
Keyword(s):  
Carbon Monoxide ◽  
Electron Transport ◽  
Cytochrome C ◽  
Acanthamoeba Castellanii ◽  
Mitochondrial Fraction ◽  
Subzero Temperatures ◽  
Soil Amoeba ◽  
Reduced Forms

1. Mitochondria-enriched fractions of the soil amoeba Acanthamoeba castellanii contained four haemoproteins that in their reduced forms reacted with CO to give photodissociable CO complexes; these were cytochromes a 3, a 614, b- and c-type cytochromes. 2. Non-photodissociable oxygen-containing compounds were formed at temperatures between -130 and -150 degrees C after photodissociation of CO in the presence of 200 microM-O2, 3. Electron transport, indicated by the oxidation of cytochromes a + a3 and cytochrome c, did not occur until the temperature was raised to -80 degrees C.

Axenic mass cultivation of the free-living soil amoeba, Acanthamoeba castellanii in a laboratory fermentor

1996 ◽  
Vol 69 (4) ◽  
pp. 317-322 ◽  
Author(s):  
Peter H. H. Weekers ◽  
John P. H. Wijen ◽  
Bart P. Lomans ◽  
Godfried D. Vogels
Keyword(s):  
Acanthamoeba Castellanii ◽  
Free Living ◽  
Mass Cultivation ◽  
Soil Amoeba ◽  
Laboratory Fermentor

scholarly journals Isolation and Identification of Free-Living Amoebae from Tap Water in Sivas, Turkey

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Kübra Açıkalın Coşkun ◽  
Semra Özçelik ◽  
Lütfi Tutar ◽  
Nazif Elaldı ◽  
Yusuf Tutar
Keyword(s):  
18S Rdna ◽  
Morphological Analysis ◽  
Tap Water ◽  
Acanthamoeba Castellanii ◽  
Isolation And Identification ◽  
Free Living ◽  
Rdna Gene ◽  
Hartmannella Vermiformis ◽  
Sequence Types ◽  
18S Rdna Gene

The present work focuses on a local survey of free-living amoebae (FLA) that cause opportunistic and nonopportunistic infections in humans. Determining the prevalence of FLA in water sources can shine a light on the need to prevent FLA related illnesses. A total of 150 samples of tap water were collected from six districts of Sivas province. The samples were filtered and seeded on nonnutrient agar containingEscherichia colispread. Thirty-three (22%) out of 150 samples were found to be positive for FLA. The FLA were identified by morphology and by PCR using 18S rDNA gene. The morphological analysis and partial sequencing of the 18S rDNA gene revealed the presence of three different species,Acanthamoeba castellanii,Acanthamoeba polyphaga, andHartmannella vermiformis.Naegleria fowleri,Balamuthia mandrillaris, orSappiniasp. was not isolated during the study. AllA. castellaniiandA. polyphagasequence types were found to be genotype T4 that contains most of the pathogenicAcanthamoebastrains. The results indicated the occurrence and distribution of FLA species in tap water in these localities of Sivas, Turkey. Furthermore, the presence of temperature tolerantAcanthamoebagenotype T4 in tap water in the region must be taken into account for health risks.

scholarly journals Phagocytosis of Cryptococcus neoformans by, and Nonlytic Exocytosis from, Acanthamoeba castellanii

2010 ◽  
Vol 76 (18) ◽  
pp. 6056-6062 ◽  
Author(s):  
Cara J. Chrisman ◽  
Mauricio Alvarez ◽  
Arturo Casadevall
Keyword(s):  
Cryptococcus Neoformans ◽  
Virulence Factors ◽  
Acanthamoeba Castellanii ◽  
Wild Type ◽  
Pathogenic Yeast ◽  
Fungal Virulence ◽  
Environmental Interactions ◽  
Soil Amoeba ◽  
Additional Support ◽  
Mammalian Infection

ABSTRACT Cryptococcus neoformans, an encapsulated, pathogenic yeast, is endowed with a variety of virulence factors, including a polysaccharide capsule. During mammalian infection, the outcome of the interaction between C. neoformans and macrophages is central to determining the fate of the host. Previous studies have shown similarities between the interaction of C. neoformans with macrophages and with amoebae, resulting in the proposal that fungal virulence for mammals originated from selection by amoeboid predators. In this study, we investigated the interaction of C. neoformans with the soil amoeba Acanthamoeba castellanii. Comparison of phagocytic efficiency of the wild type, nonencapsulated mutants, and complemented strains showed that the capsule was antiphagocytic for amoebae. Capsular enlargement was associated with a significant reduction in phagocytosis, suggesting that this phenomenon protects against ingestion by phagocytic predators. C. neoformans var. neoformans cells were observed to exit amoebae several hours after ingestion, in a process similar to the recently described nonlytic exocytosis from macrophages. Cryptococcal exocytosis from amoebae was dependent on the strain and on actin and required fungal viability. Additionally, the presence of a capsule was inversely correlated with the likelihood of extrusion in certain strains. In summary, nonlytic exocytosis from amoebae provide another parallel to observations in fungus-macrophage interactions. These results provide additional support for the notion that some mechanisms of virulence observed during mammalian infection originated, and were selected for, by environmental interactions.

scholarly journals Could insect phagocytic avoidance by entomogenous fungi have evolved via selection against soil amoeboid predators?

Microbiology ◽  
2010 ◽  
Vol 156 (7) ◽  
pp. 2164-2171 ◽  
Author(s):  
Michael J. Bidochka ◽  
David C. Clark ◽  
Mike W. Lewis ◽  
Nemat O. Keyhani
Keyword(s):  
Legionella Pneumophila ◽  
Metarhizium Anisopliae ◽  
Soil Fungi ◽  
Acanthamoeba Castellanii ◽  
Pathogenic Fungi ◽  
Insect Cuticle ◽  
Entomogenous Fungi ◽  
Insect Pathogenic Fungi ◽  
Soil Amoeba ◽  
Insect Pathogens

The entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana are ubiquitously distributed in soils. As insect pathogens they adhere to the insect cuticle and penetrate through to the insect haemocoel using a variety of cuticle-hydrolysing enzymes. Once in the insect haemocoel they are able to survive and replicate within, and/or evade, phagocytic haemocyte cells circulating in the haemolymph. The mechanism by which these soil fungi acquire virulence factors for insect infection and insect immune avoidance is unknown. We hypothesize that insect phagocytic cell avoidance in M. anisopliae and B. bassiana is the consequence of a survival strategy against soil-inhabiting predatory amoebae. Microscopic examination, phagocytosis assays and amoeba mortality assays showed that these insect pathogenic fungi are phagocytosed by the soil amoeba Acanthamoeba castellanii and can survive and grow within the amoeba, resulting in amoeba death. Mammalian fungal and bacterial pathogens, such as Cryptococcus neoformans and Legionella pneumophila, respectively, show a remarkable overlap between survival against soil amoebae and survival against human macrophages. The insect immune system, particularly phagocytic haemocytes, is analogous to the mammalian macrophage. Our data suggest that the ability of the fungal insect pathogens M. anisopliae and B. bassiana to survive insect phagocytic haemocytes may be a consequence of adaptations that have evolved in order to avoid predation by soil amoebae.

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