scholarly journals Rapid Detection and Enumeration of Naegleria fowleri in Surface Waters by Solid-Phase Cytometry

2002 ◽  
Vol 68 (6) ◽  
pp. 3102-3107 ◽  
Author(s):  
Claire Pougnard ◽  
Philippe Catala ◽  
Jean-Louis Drocourt ◽  
Stephane Legastelois ◽  
Pierre Pernin ◽  
...  
Keyword(s):  
Surface Waters ◽  
Solid Phase ◽  
Fluorescein Isothiocyanate ◽  
Environmental Water ◽  
New Method ◽  
Naegleria Fowleri ◽  
Reporter Systems ◽  
Nægleria Fowleri ◽  
Filtration Capacity ◽  
Direct Counts

ABSTRACT A new method for the rapid and accurate detection of pathogenic Naegleria fowleri amoebae in surface environmental water was developed. The method is based on an immunofluorescent assay combined with detection by solid-phase cytometry. In this study we developed and compared two protocols using different reporter systems conjugated to antibodies. The monoclonal antibody Ac5D12 was conjugated with biotin and horseradish peroxidase, and the presence of cells was revealed with streptavidin conjugated to both R-phycoerythrin and cyanine Cy5 (RPE-Cy5) and tyramide-fluorescein isothiocyanate, respectively. The RPE-Cy5 protocol was the most efficient protocol and allowed the detection of both trophozoite and cyst forms in water. The direct counts obtained by this new method were not significantly different from those obtained by the traditional culture approach, and results were provided within 3 h. The sensitivity of the quantitative method is 200 cells per liter. The limit is due only to the filtration capacity of the membrane used.

scholarly journals Comparative Recoveries of Naegleria fowleri Amoebae from Seeded River Water by Filtration and Centrifugation

1998 ◽  
Vol 64 (3) ◽  
pp. 955-959 ◽  
Author(s):  
P. Pernin ◽  
M. Pélandakis ◽  
Y. Rouby ◽  
A. Faure ◽  
F. Siclet
Keyword(s):  
Environmental Water ◽  
Most Probable Number ◽  
Naegleria Fowleri ◽  
Probable Number ◽  
Cystic Form ◽  
Low Concentrations ◽  
The Difference ◽  
Nægleria Fowleri ◽  
Concentration Methods ◽  
Amoebic Meningoencephalitis

ABSTRACT Detection of pathogenic Naegleria fowleri in environmental water samples, which is necessary for the prevention of primary amoebic meningoencephalitis, generally requires concentrating the samples. Two concentration techniques, filtration and centrifugation, were used to study the recovery of N. fowleri, in vegetative or cystic form, that had been mixed with the two other thermotolerant Naegleria species, N. lovaniensis and N. australiensis. Counting of amoebae was performed by the most probable number method on 10 water replicates of 100 ml and 10 ml each. With both concentration methods, recovery was better for cysts than for trophozoites (53% ± 21% versus 5% ± 5% by filtration and 57% ± 25% versus 22% ± 5% by centrifugation). The recovery of Naegleria trophozoites by filtration was very low, and centrifugation was significantly better than filtration in recovery of Naegleria trophozoites (22% ± 5% versus 5% ± 5%; P < 0.001). For cysts, however, filtration appeared as efficient as centrifugation, with equivalent values for recovery (53% ± 21% versus 57% ± 25%;P > 0.7). Although the recovery of cysts of N. fowleri obtained by filtration (51% ± 24%) appeared higher than that by centrifugation (36% ± 23%), the difference was not significant (P > 0.1). Both concentration methods have highly variable recovery rates, making accurate quantification of low concentrations (<100/liter) of N. fowleri in the environment difficult.

scholarly journals Quantitative assessment of Naegleria fowleri and Escherichia coli concentrations within a Texas reservoir

2013 ◽  
Vol 11 (2) ◽  
pp. 346-357 ◽  
Author(s):  
Stephanie M. Painter ◽  
Russell S. Pfau ◽  
Jeff A. Brady ◽  
Anne M. S. McFarland
Keyword(s):  
Escherichia Coli ◽  
Surface Waters ◽  
Water Samples ◽  
Late Summer ◽  
Naegleria Fowleri ◽  
Fecal Indicator ◽  
E Coli ◽  
Environmental Surface ◽  
Polymerase Chain ◽  
Nægleria Fowleri

Previous presence/absence studies have indicated a correlation between the presence of the pathogenic amoeba Naegleria fowleri and the presence of bacteria, such as the fecal indicator Escherichia coli, in environmental surface waters. The objective of this study was to use quantitative real-time polymerase chain reaction (qPCR) methodologies to measure N. fowleri and E. coli concentrations within a Texas reservoir in late summer, and to determine if concentrations of N. fowleri and E. coli were statistically correlated. N. fowleri was detected in water samples from 67% of the reservoir sites tested, with concentrations ranging up to an estimated 26 CE (cell equivalents)/100 mL. E. coli was detected in water samples from 60% of the reservoir sites tested, with concentrations ranging up to 427 CE/100 mL. In this study, E. coli concentrations were not indicative of N. fowleri concentrations.

An Enzyme-Linked ImmunoSorbent Assay (ELISA) for the Identification of Naegleria fowleri in Environmental Water Samples

2003 ◽  
Vol 50 (2) ◽  
pp. 109-113 ◽  
Author(s):  
FABIENNE L. REVEILLER ◽  
MARIE-PIERRE VARENNE ◽  
CLAIRE POUGNARD ◽  
PIERRE-ANDRE CABANES ◽  
EMMANUELLE PRINGUEZ ◽  
...  
Keyword(s):  
Immunosorbent Assay ◽  
Water Samples ◽  
Environmental Water ◽  
Environmental Water Samples ◽  
Enzyme Linked Immunosorbent Assay ◽  
Naegleria Fowleri ◽  
Nægleria Fowleri

Efficacy of a combined system of copper and silver and free chlorine for inactivation of Naegleria fowleri amoebas in water

1995 ◽  
Vol 31 (5-6) ◽  
pp. 119-122 ◽  
Author(s):  
J. M. Cassells ◽  
M. T. Yahya ◽  
C. P. Gerba ◽  
J. B. Rose
Keyword(s):  
Synergistic Effect ◽  
Exposure Time ◽  
Silver Ions ◽  
Free Chlorine ◽  
Log10 Reduction ◽  
Naegleria Fowleri ◽  
Combined System ◽  
Water Ph ◽  
Nægleria Fowleri ◽  
Time Required

Electrolytically generated copper and silver ions (400:40 and 800:80 μg/l) were evaluated, separately and combined with 1.0 mg/l free chlorine, for their efficacy in reducing the viable numbers of Naegleria fowleri amoebas in water (pH 7.3 and 23-25°C). Inactivation rates (k = log10 reduction/min) and T99 values (exposure time required to achieve a 99% or a 2 log10 reduction) of the disinfectants were determined. Copper and silver alone, at ratio of 400:40 to 800:80 μg/l caused no significant inactivation of N. fowleri even after 72 hours of exposure (k = 0.00017 and 0.00013, respectively). Addition of 1.0 mg/l free chlorine to water which contained 400:40 or 800:80 μg/l copper and silver resulted in enhanced inactivation rates (k = 0.458 and 0.515, respectively) compared to either chlorine alone (k = 0.33) or the metals alone. Water containing 800:80 μg/l copper and silver with 1.0 mg/l chlorine showed a T99 value of 3.9 minutes, while chlorine alone showed a T99 of 6.1 minutes. Enhanced inactivation of N. fowleri by a combined system of free chlorine and copper and silver may be attributed to the different mechanism that each disinfectant utilizes in inactivating the amoebas, and may suggest a synergistic effect.

The Use of Solid Phase Microextraction (SPME) to Monitor for Major Organoleptic Compounds Produced by Chrysophytes in Surface Waters

1999 ◽  
Vol 40 (6) ◽  
pp. 251-256 ◽  
Author(s):  
Susan B. Watson ◽  
Brian Brownlee ◽  
Trevor Satchwill ◽  
E. McCauley
Keyword(s):  
Surface Waters ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Small Sample ◽  
Good Recovery ◽  
Culture Material ◽  
Treatment Facilities ◽  
Efficient Extraction ◽  
Cost Efficient ◽  
Related Compounds

An efficient extraction method is needed to measure trace levels of taste and odour compounds in surface waters. This is usually accomplished by costly and involved analytical procedures. We have developed a simpler alternative, using a commercially available microextraction apparatus (SPME). With this technique we successfully monitored trace levels of some target organoleptics (unsaturated aldehydes e.g. heptadienal, nonadienal, and related compounds) which commonly cause aquatic taste and odour. We identified these compounds in culture material, and analyzed for them during the development of odourous chrysophyte blooms in two ponds. Preliminary work has also found a good recovery of some important off-flavour terpenoids (e.g. geosmin and MIB). SPME is labour and cost efficient, and therefore appealing to water treatment facilities for detection and monitoring. In addition, SPME requires only small sample volumes, and is therefore suitable for culture work.

Application of Silica Nanoparticles in the Determination of Herbicides in Environmental Water Samples Using Liquid Chromatography-Mass Spectroscopy

2020 ◽  
Vol 16 (5) ◽  
pp. 748-756
Author(s):  
Mir Waqas Alam ◽  
Tentu Nageswara Rao ◽  
Yarasani Prashanthi ◽  
Vourse Sridhar ◽  
Adil Alshoaibi ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Liquid Chromatography ◽  
Silica Nanoparticles ◽  
Solid Phase ◽  
Silica Nanoparticle ◽  
Environmental Water ◽  
Phase Extraction ◽  
Functionalized Nanoparticles ◽  
Supporting Material

Background: Herbicides are very beneficial in the crop yield with the aid of controlling weeds within the agriculture, but several herbicides are chronic in soil. Objective: In this study, nanoparticles and the packages of synthesized novel silica nanoparticles were studied for the preconcentration of herbicides. Methods: These nanoparticles prepared by the Stöber mechanism were purified and functionalized. Nanoparticles thus prepared successfully were used as supporting material for the preconcentration of residues of herbicides in the water. Results: Preconcentration was achieved by preparing the silica-based solid-phase-extraction cartridges. Nanoparticles used for this purpose were within the range of 50-250 nm. An SPE cartridge was prepared by packing 200 mg of silica nanoparticle in the empty cartridge of diameter 5.5 cm and length 0.6 cm in between PTFE frits. Aqueous solutions of 0.1 μg/ml of herbicides were prepared separately, and 10 ml of the solution was passed through the cartridge at the rate of 0.2 ml/min. After passing 10 ml volume of the aqueous solution, residues adsorbed on the cartridge were eluted using 2 ml of acetonitrile. The eluate was injected to determine the herbicide residue adsorbed on the SPE cartridge. Conclusion: In the study, it was found that greater than 90% of the herbicide residues were trapped on silica nanoparticle-based SPE cartridge. An analytical method was developed for the simultaneous determination of these herbicides. The residues were quantified by LC-MS/MS with ESI mode.

scholarly journals A Novel Cysteine Protease Inhibitor of Naegleria fowleri That Is Specifically Expressed during Encystation and at Mature Cysts

Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 388
Author(s):  
Hương Giang Lê ◽  
A-Jeong Ham ◽  
Jung-Mi Kang ◽  
Tuấn Cường Võ ◽  
Haung Naw ◽  
...  
Keyword(s):  
Protease Inhibitor ◽  
Cysteine Protease ◽  
Expression Profiles ◽  
Critical Role ◽  
Cyst Formation ◽  
Cysteine Proteases ◽  
Cysteine Protease Inhibitor ◽  
Naegleria Fowleri ◽  
Nægleria Fowleri ◽  
Cystatin Family

Naegleria fowleri is a free-living amoeba that is ubiquitous in diverse natural environments. It causes a fatal brain infection in humans known as primary amoebic meningoencephalitis. Despite the medical importance of the parasitic disease, there is a great lack of knowledge about the biology and pathogenicity of N. fowleri. In this study, we identified and characterized a novel cysteine protease inhibitor of N. fowleri (NfCPI). NfCPI is a typical cysteine protease inhibitor belonging to the cystatin family with a Gln-Val-Val-Ala-Gly (QVVAG) motif, a characteristic motif conserved in the cystatin family of proteins. Bacterially expressed recombinant NfCPI has a dimeric structure and exhibits inhibitory activity against several cysteine proteases including cathespin Bs of N. fowleri at a broad range of pH values. Expression profiles of nfcpi revealed that the gene was highly expressed during encystation and cyst of the amoeba. Western blot and immunofluorescence assays also support its high level of expression in cysts. These findings collectively suggest that NfCPI may play a critical role in encystation or cyst formation of N. fowleri by regulating cysteine proteases that may mediate encystation or mature cyst formation of the amoeba. More comprehensive studies to investigate the roles of NfCPI in encystation and its target proteases are necessary to elucidate the regulatory mechanism and the biological significance of NfCPI.

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