quantation by flow microfluorometry of total cellular dna in acanthamoeba.the dna content of five species of acanthamoeba was determined by flow microfluorometry. acanthamoeba castellanii (ac-30), acanthamoeba polyphaga (apg and p-23), acanthamoeba rhysodes, acanthamoeba culbertsoni (a-1), and acanthamoeba royreba were grown in a casitone based medium 24-48 hr. the trophozoites were harvested, and evaluated for dna-bound fluorescence. all species tested has dna values between 2.0-5.0 pg/cell. these results placed dna/cell values of acanthamoeba slightly lower than dna ...1978361883
acanthamoeba keratitis and infectious crystalline keratopathy.two cases of acanthamoeba keratitis and infectious crystalline keratopathy, occurring simultaneously, are presented. three and 12 months after initiating topical corticosteroid therapy in cases 1 and 2, respectively, alpha-hemolytic streptococcus viridans was cultured from each cornea. topical corticosteroid therapy was initiated for the treatment of an annular stromal opacity, presumably secondary to herpes simplex keratitis. acanthamoeba was identified in culture following penetrating keratopl ...19873314824
separate induction of amitotic and mitotic division in acanthamoeba rhysodes. 19705428435
primary amoebic meningoencephalitis in a young male from northwestern mexico.primary meningoencephalitis caused by naegleria fowleri was documented in a 16-year-old male from mexicali in the state of baja california in mexico. in august 1978, seven days after sustaining moderate head trauma while swimming in a shallow, stagnant irrigation ditch on a hot summer day, the patient presented an acute illness with severe headache, fever and convulsions rapidly progressing into a comatose state. actively moving trophozoites were observed in the spinal fluid on admission. the pa ...19846485064
isolation and identification of free-living amoebae from some water sources in alexandria.samples from different water sources of alexandria, and from nasal passages of 500 healthy children inhabiting areas nearby these sources were examined for the presence of free-living amoebae. these samples were cultured on 1.5% non nutrient agar streaked with bacteria. amoebae were isolated and identified by means of their morphological characters and ability to produce flagellated forms. characteristics of the cystic stages and pattern of excystation also aided in the identification of the var ...19948077745
subgenus systematics of acanthamoeba: four nuclear 18s rdna sequence types.classification of acanthamoeba at the subgenus level has been problematic, but increasing reports of acanthamoeba as an opportunistic human pathogen have generated an interest in finding a more consistent basis for classification. thus, we are developing a classification scheme based on rna gene sequences. this first report is based on analysis of complete sequences of nuclear small ribosomal subunit rna genes (rns) from 18 strains. sequence variation was localized in 12 highly variable regions. ...19968976608
in vitro shock response to different stressors in free living and pathogenic acanthamoeba.three stresses, viz heat, oxidative and ph shocks, were applied to cultures of three species of acanthamoeba, free-living acanthamoeba rhysodes and pathogenic acanthamoeba castellanii and acanthamoeba culbertsoni. the effect of each stressor on trophozoite integrity was evaluated by the amount of heat shock protein (hsp)60 and hsp70 produced and by exclusion of 0.2% congo red. hsp60 and hsp70 levels were estimated using western blotting and subsequent densitometric analyses. unstimulated trophoz ...200010899527
uptake and replication of salmonella enterica in acanthamoeba rhysodes.the ability of salmonellae to become internalized and to survive and replicate in amoebae was evaluated by using three separate serovars of salmonella enterica and five different isolates of axenic acanthamoeba spp. in gentamicin protection assays, salmonella enterica serovar dublin was internalized more efficiently than salmonella enterica serovar enteritidis or salmonella enterica serovar typhimurium in all of the amoeba isolates tested. the bacteria appeared to be most efficiently internalize ...200415184177
salmonella enterica spvb-mediated adp-ribosylation as an activator for host cell actin degradation.the virulence-associated spvb protein of salmonella enterica is a mono (adp-ribosyl)transferase defined to target mammalian actin. exposure of acanthamoeba rhysodes cell lysate with spvb and [32p]nicotinamide adenine dinucleotide (nad) was here observed to result in labeling of a protein of 43 kda that subsequently was identified as actin by immunoprecipitation. in parallel, adp-ribosylation promoted degradation of the protozoan actin. spvb-mediated actin degradation occurred in the presence of ...200516128395
resistance of cysts of amoebae to microbial decomposition.cyst walls of acanthamoeba rhysodes, a. palestinensis, a. castellanii, and one other strain of acanthamoeba contain 36 to 45% protein and 20 to 34% carbohydrate. more than half of the protein in the walls of a. palestinensis, a. castellanii and acanthamoeba sp. is accessible to and hydrolyzed by protease, and 67 to 69% of the carbohydrate of a. palestinensis and a. rhysodes walls is hydrolyzed by cellulase. the extent of hydrolysis of walls of the other amoebae by these enzymes is appreciably le ...197716345225
a simple method for long-term storage of acanthamoeba species.we present a novel and simple technique for storing live acanthamoeba for long periods of time. the amoebae are maintained at refrigerator temperatures in a peptone-yeast extract-glucose (pyg) medium normally used for cultivation. using this method, we obtained survival rates of at least 4 years for acanthamoeba polyphaga and 3 years for acanthamoeba castellanii and acanthamoeba rhysodes. advantages of this storage method are: (1) it is quick and simple, (2) inexpensive, (3) does not require enc ...200919089450
apoptosis-like cell death induced by salmonella in acanthamoeba amoebae act as environmental hosts of several intracellular pathogens. we examined the interaction between acanthamoeba rhysodes and salmonella, a human intracellular pathogen. there was no difference among three different serovars of salmonella in terms of their growth within a. rhysodes over time. the number of intracellular bacteria increased at 6 h post-infection, and the viability of a. rhysodes was significantly reduced at 24 h post-infection. amoebic cell death was characteriz ...200919446019
amoebae and algae can prolong the survival of campylobacter species in co-culture.several species of free-living amoebae can cause disease in humans. however, in addition to the direct pathogenicity of e.g. acanthamoebae and naegleria species, they are recognized as environmental hosts, indirectly involved in the epidemiology of many pathogenic bacteria. although several studies have demonstrated intracellular survival of many different bacteria in these species, the extent of such interactions as well as the implications for the epidemiology of the bacterial species involved ...201020056117
ether-type moieties in the lipid part of glycoinositolphospholipids of acanthamoeba rhysodes.ether lipids were identified among components liberated with hf and nitrous acid deamination from acanthamoeba rhysodes whole cells and its membrane glycoinositolphospholipids (gipl). liberated ether glycerols were converted to various derivatives that served characterization thereof. these included tms and isopropylidene derivatives, oxidation with sodium periodate to aldehyde followed by reduction with nabh4 to alcohol, and reaction of the alcohol with acetic anhydrite to form acetate derivati ...201424535098
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