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Papers by Elena Dlusskaya
IWA Publishing eBooks, Jun 14, 2022
Methods in molecular biology, Nov 15, 2023
Journal of Water and Health, 2021
In recent decades, natural swimming pools (NSPs) have gained popularity in Europe, especially in ... more In recent decades, natural swimming pools (NSPs) have gained popularity in Europe, especially in Germany and Austria. NSPs differ from swimming pools in that they utilize biological treatment processes based on wetland processes with no disinfection residual. However, data are missing on the specific log-reduction performance of NSPs to address enteric virus, bacteria, and parasitic protozoa removal considered necessary to meet the North American risk-based benchmark (<35 illnesses per 1,000 swimming events) set by the USEPA for voluntary swimming. In this study, we examined Canada's first NSP at Borden Park, Edmonton, Canada, to address the following three questions: (1) Given normal faecal shedding rates by bathers, what is the total log reduction (TLR) theoretically needed to meet the EPA benchmark? (2) what is the in-situ performance of the NSP based on spiking suitable microbial surrogates (MS2 coliphage, Enterococcus faecalis, and Saccharomyces cerevisiae [Baker's y...
Journal of Water and Health
Rising temperatures are increasing environmental habitats for thermotolerant pathogens, such as t... more Rising temperatures are increasing environmental habitats for thermotolerant pathogens, such as the so-called ‘brain-eating amoeba’, Naegleria fowleri. To the best of our knowledge, however, Naegleria species have not been reported in environmental water sources in Canada. We surveyed popular recreational lakes in Alberta, Canada during the summer bathing period to determine the presence or absence of Naegleria species. While N. fowleri was not isolated in this study, we identified other thermotolerant species, including Naegleria pagei, Naegleria gruberi, Naegleria jejuensis and Naegleria fultoni using culture-based methods, hence indicating the potential conditions to support N. fowleri. Ongoing monitoring and examination of water for pathogenic amoebae is recommended in order to assist in the public health management of water sources.
Increasing freshwater scarcity drives humankind to look for alternative sources of potable water ... more Increasing freshwater scarcity drives humankind to look for alternative sources of potable water as well as water for agricultural and industrial applications. It is estimated that by 2025 half of the world population will be living in water-scarce regions. This pressure has forced governments to explore alternative water sources and more sustainable approaches to manage water services. Municipal wastewater reuse is part of the solution Preface Some of the research conducted for this thesis forms part of a research project
ACS ES&T Water, 2021
The use of flow cytometry (FCM) with environmental or clinical samples to enumerate viruses (flow... more The use of flow cytometry (FCM) with environmental or clinical samples to enumerate viruses (flow virometry) has become popular with the development of sensitive fluorescent dyes that bind to nucle...
Journal of Water and Health, 2021
The reported persistence of SARS-CoV-2 virions in aquatic environments highlights the need to bet... more The reported persistence of SARS-CoV-2 virions in aquatic environments highlights the need to better understand potential mechanisms that may prolong its dissemination. We evaluated the possibility that amoebae might serve as transport hosts by studying the interaction of the enveloped bacteriophage Phi6, as a potential surrogated along with one of the most common amoebae in engineered aquatic environments, Vermamoeba vermiformis. Using microscopy, imaging flow cytometry and bacteriophage cell culture, our results imply that the SARS-CoV-2 surrogate triggers amoebic mitochondria and induced apoptosis to promote viral persistence in trophozoites. Furthermore, virus-infected amoebae were still infectious after 2 months within FLA cysts. These results suggest that amoebae could contribute to the environmental persistence of SARS-CoV-2, including disinfection processes. In addition, amoebae could be a successful model system for understanding respiratory virus-eukaryotic biology at the ...
Science of The Total Environment, 2019
Isolates tolerated alkaline pH, high salinity and NA concentrations far exceeding typical of OSPW... more Isolates tolerated alkaline pH, high salinity and NA concentrations far exceeding typical of OSPW. • Trichoderma harzianum can grow with pure NAs as sole source of carbon. • OSPW toxicity showed higher cytotoxicity than just NAs alone. • Possible synergistic effect of other components of OSPW with NAs attributed to toxicity • Membrane disruption and fluidity not the cause of toxic effects of NAs
Water Research X, 2019
Flow cytomtery (FCM) has become a standard approach to enumerate viruses in water research. Howev... more Flow cytomtery (FCM) has become a standard approach to enumerate viruses in water research. However, the nature of the fluorescent signal in flow cytometric analysis of water samples and the mechanism of its formation, have not been addressed for bacteriophages expected in wastewaters. Here we assess the behaviour of fluorescent DNA-staining dyes in aqueous solutions, as well as sensitivity and accuracy of FCM for enumeration of DNA-stained model bacteriophages l, P1, and T4. We demonstrate that in aqueous systems fluorescent dyes form a self-stabilized (pseudolyophilic) emulsion of autofluorescing colloid particles. Sample shaking and addition of surfactants enhance auto-fluorescence due to increased dispersion and, in the presence of surfactants, stabilization of the dye emulsion. Bacteriophages with genome sizes <100 kbp (i.e. l & P1) did not generate a distinct population signal to be detected by one of the most sensitive FCM instruments available (BD LSR Fortessa™ X-20), whereas the larger T4 bacteriophage was resolved as a distinct population of events. These results indicate that the use of fluorescent dyes for bacteriophage enumeration by flow cytometry can produce false positive signals and lead to wrong estimation of total virus counts by misreporting colloid particles as virions, depending on instrument sensitivity.
Journal of Applied Microbiology, 2011
This study aimed to determine the survival of Escherichia coli strains during steam and lactic ac... more This study aimed to determine the survival of Escherichia coli strains during steam and lactic acid decontamination interventions currently used by the beef-processing industry, and to determine their heat resistance. Strains were grouped into cocktails of five strains each differing in their RAPD patterns for subsequent identification. Steam and lactic acid treatments on meat reduced cell counts of E. coli strain cocktails by 90-99%. The 20 slaughter plant isolates exhibited only minor variation in their resistance to steam and lactic acid treatments but were more resistant than reference strains (three strains) or isolates from live cattle (seven strains). D(60) values of strains from live cattle, and reference strains ranged from 0·1 to 0·5 min, in keeping with literature data. However, D(60) values of current slaughter plant isolates ranged between 15 for E. coli DM18.3 and 71 min AW 1.7. Cell counts of E. coli AW 1.7 were reduced by &amp;lt;5 log(10) CFU g(-1) in ground beef patties cooked to an internal temperature of 71°C. Strains of E. coli that survive cooking of ground beef to the recommended internal temperature of 71°C can be isolated from beef-processing facilities. Pathogen interventions in current commercial beef slaughter may select for extremely heat-resistant strains of E. coli.
European Food Research and Technology, 2007
Kvass is a fermented cereal beverage which produced from malt, rye Xour, stale rye bread, and suc... more Kvass is a fermented cereal beverage which produced from malt, rye Xour, stale rye bread, and sucrose and is consumed mainly in Eastern Europe. Moreover, it is of interest as one of the few examples of traditional, non-alcoholic cereal-based beverages. In this study, a commercial kvass sample was characterized with respect to the fermentation microXora and the concentration of microbial metabolites. Lactobacillus casei and Leuconostoc mesenteroides were present in cell counts of 7.3 £ 10 7 and 6.0 £ 10 7 cfu mL ¡1 , respectively. Saccharomyces cerevisiae was present in cell counts of 3.0 £ 10 7 cfu mL ¡1. PCR-DGGE analysis veriWed that all dominant fermentation organisms were cultivated. Microbial metabolites in kvass were ethanol, lactate, and acetate. One of the kvass isolates, Ln. mesenteroides FUA 3086 harboured a putative dextransucrase gene and formed dextran and isomalto-oligosaccharides from sucrose and maltose. Fermentation of model kvass wort conWrmed that all kvass isolates grew in the fermentation substrate, moreover, formation of isomaltotriose by Ln. mesenteroides FUA 3086 was observed in model kvass fermentation.
IWA Publishing eBooks, Jun 14, 2022
Methods in molecular biology, Nov 15, 2023
Journal of Water and Health, 2021
In recent decades, natural swimming pools (NSPs) have gained popularity in Europe, especially in ... more In recent decades, natural swimming pools (NSPs) have gained popularity in Europe, especially in Germany and Austria. NSPs differ from swimming pools in that they utilize biological treatment processes based on wetland processes with no disinfection residual. However, data are missing on the specific log-reduction performance of NSPs to address enteric virus, bacteria, and parasitic protozoa removal considered necessary to meet the North American risk-based benchmark (<35 illnesses per 1,000 swimming events) set by the USEPA for voluntary swimming. In this study, we examined Canada's first NSP at Borden Park, Edmonton, Canada, to address the following three questions: (1) Given normal faecal shedding rates by bathers, what is the total log reduction (TLR) theoretically needed to meet the EPA benchmark? (2) what is the in-situ performance of the NSP based on spiking suitable microbial surrogates (MS2 coliphage, Enterococcus faecalis, and Saccharomyces cerevisiae [Baker's y...
Journal of Water and Health
Rising temperatures are increasing environmental habitats for thermotolerant pathogens, such as t... more Rising temperatures are increasing environmental habitats for thermotolerant pathogens, such as the so-called ‘brain-eating amoeba’, Naegleria fowleri. To the best of our knowledge, however, Naegleria species have not been reported in environmental water sources in Canada. We surveyed popular recreational lakes in Alberta, Canada during the summer bathing period to determine the presence or absence of Naegleria species. While N. fowleri was not isolated in this study, we identified other thermotolerant species, including Naegleria pagei, Naegleria gruberi, Naegleria jejuensis and Naegleria fultoni using culture-based methods, hence indicating the potential conditions to support N. fowleri. Ongoing monitoring and examination of water for pathogenic amoebae is recommended in order to assist in the public health management of water sources.
Increasing freshwater scarcity drives humankind to look for alternative sources of potable water ... more Increasing freshwater scarcity drives humankind to look for alternative sources of potable water as well as water for agricultural and industrial applications. It is estimated that by 2025 half of the world population will be living in water-scarce regions. This pressure has forced governments to explore alternative water sources and more sustainable approaches to manage water services. Municipal wastewater reuse is part of the solution Preface Some of the research conducted for this thesis forms part of a research project
ACS ES&T Water, 2021
The use of flow cytometry (FCM) with environmental or clinical samples to enumerate viruses (flow... more The use of flow cytometry (FCM) with environmental or clinical samples to enumerate viruses (flow virometry) has become popular with the development of sensitive fluorescent dyes that bind to nucle...
Journal of Water and Health, 2021
The reported persistence of SARS-CoV-2 virions in aquatic environments highlights the need to bet... more The reported persistence of SARS-CoV-2 virions in aquatic environments highlights the need to better understand potential mechanisms that may prolong its dissemination. We evaluated the possibility that amoebae might serve as transport hosts by studying the interaction of the enveloped bacteriophage Phi6, as a potential surrogated along with one of the most common amoebae in engineered aquatic environments, Vermamoeba vermiformis. Using microscopy, imaging flow cytometry and bacteriophage cell culture, our results imply that the SARS-CoV-2 surrogate triggers amoebic mitochondria and induced apoptosis to promote viral persistence in trophozoites. Furthermore, virus-infected amoebae were still infectious after 2 months within FLA cysts. These results suggest that amoebae could contribute to the environmental persistence of SARS-CoV-2, including disinfection processes. In addition, amoebae could be a successful model system for understanding respiratory virus-eukaryotic biology at the ...
Science of The Total Environment, 2019
Isolates tolerated alkaline pH, high salinity and NA concentrations far exceeding typical of OSPW... more Isolates tolerated alkaline pH, high salinity and NA concentrations far exceeding typical of OSPW. • Trichoderma harzianum can grow with pure NAs as sole source of carbon. • OSPW toxicity showed higher cytotoxicity than just NAs alone. • Possible synergistic effect of other components of OSPW with NAs attributed to toxicity • Membrane disruption and fluidity not the cause of toxic effects of NAs
Water Research X, 2019
Flow cytomtery (FCM) has become a standard approach to enumerate viruses in water research. Howev... more Flow cytomtery (FCM) has become a standard approach to enumerate viruses in water research. However, the nature of the fluorescent signal in flow cytometric analysis of water samples and the mechanism of its formation, have not been addressed for bacteriophages expected in wastewaters. Here we assess the behaviour of fluorescent DNA-staining dyes in aqueous solutions, as well as sensitivity and accuracy of FCM for enumeration of DNA-stained model bacteriophages l, P1, and T4. We demonstrate that in aqueous systems fluorescent dyes form a self-stabilized (pseudolyophilic) emulsion of autofluorescing colloid particles. Sample shaking and addition of surfactants enhance auto-fluorescence due to increased dispersion and, in the presence of surfactants, stabilization of the dye emulsion. Bacteriophages with genome sizes <100 kbp (i.e. l & P1) did not generate a distinct population signal to be detected by one of the most sensitive FCM instruments available (BD LSR Fortessa™ X-20), whereas the larger T4 bacteriophage was resolved as a distinct population of events. These results indicate that the use of fluorescent dyes for bacteriophage enumeration by flow cytometry can produce false positive signals and lead to wrong estimation of total virus counts by misreporting colloid particles as virions, depending on instrument sensitivity.
Journal of Applied Microbiology, 2011
This study aimed to determine the survival of Escherichia coli strains during steam and lactic ac... more This study aimed to determine the survival of Escherichia coli strains during steam and lactic acid decontamination interventions currently used by the beef-processing industry, and to determine their heat resistance. Strains were grouped into cocktails of five strains each differing in their RAPD patterns for subsequent identification. Steam and lactic acid treatments on meat reduced cell counts of E. coli strain cocktails by 90-99%. The 20 slaughter plant isolates exhibited only minor variation in their resistance to steam and lactic acid treatments but were more resistant than reference strains (three strains) or isolates from live cattle (seven strains). D(60) values of strains from live cattle, and reference strains ranged from 0·1 to 0·5 min, in keeping with literature data. However, D(60) values of current slaughter plant isolates ranged between 15 for E. coli DM18.3 and 71 min AW 1.7. Cell counts of E. coli AW 1.7 were reduced by &amp;lt;5 log(10) CFU g(-1) in ground beef patties cooked to an internal temperature of 71°C. Strains of E. coli that survive cooking of ground beef to the recommended internal temperature of 71°C can be isolated from beef-processing facilities. Pathogen interventions in current commercial beef slaughter may select for extremely heat-resistant strains of E. coli.
European Food Research and Technology, 2007
Kvass is a fermented cereal beverage which produced from malt, rye Xour, stale rye bread, and suc... more Kvass is a fermented cereal beverage which produced from malt, rye Xour, stale rye bread, and sucrose and is consumed mainly in Eastern Europe. Moreover, it is of interest as one of the few examples of traditional, non-alcoholic cereal-based beverages. In this study, a commercial kvass sample was characterized with respect to the fermentation microXora and the concentration of microbial metabolites. Lactobacillus casei and Leuconostoc mesenteroides were present in cell counts of 7.3 £ 10 7 and 6.0 £ 10 7 cfu mL ¡1 , respectively. Saccharomyces cerevisiae was present in cell counts of 3.0 £ 10 7 cfu mL ¡1. PCR-DGGE analysis veriWed that all dominant fermentation organisms were cultivated. Microbial metabolites in kvass were ethanol, lactate, and acetate. One of the kvass isolates, Ln. mesenteroides FUA 3086 harboured a putative dextransucrase gene and formed dextran and isomalto-oligosaccharides from sucrose and maltose. Fermentation of model kvass wort conWrmed that all kvass isolates grew in the fermentation substrate, moreover, formation of isomaltotriose by Ln. mesenteroides FUA 3086 was observed in model kvass fermentation.