Parasites of the genus Cryptosporidium are a major cause of diarrhoea and ill-health in humans and animals and are frequent causes of waterborne outbreaks. Until recently, it was thought that ...Cryptosporidium was an obligate intracellular parasite that only replicated within a suitable host, and that faecally shed oocysts could survive in the environment but could not multiply. In light of extensive biological and molecular data, including the ability of Cryptosporidium to complete its life cycle in the absence of a host and the production of novel extracellular stages, Cryptosporidium has been formally transferred from the Coccidia, to a new subclass, Cryptogregaria, with gregarine parasites. In this review, we discuss the close relationship between Cryptosporidium and gregarines and discuss the implications for the water industry.
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•Cryptosporidium now grouped with gregarine parasites.•Both epicellular and extracellular development.•Can diagnostic antibodies cross-react with novel stages?•Susceptibility of novel stages to disinfection?•Growth in biofilms?
Cyanobacteria are one of the principal sources of volatile organic compounds (VOCs) which cause offensive taste and odor (T&O) in drinking and recreational water, fish, shellfish and other seafood. ...Although non-toxic to humans, these T&O compounds severely undermine public trust in these commodities, resulting in substantial costs in treatment, and lost revenue to drinking water, aquaculture, food and beverage and tourist/hospitality industries. Mitigation and control have been hindered by the complexity of the communities and processes which produce and modify T&O events, making it difficult to source-track the major producer(s) and the factors governing VOC production and fate. Over the past decade, however, advances in bioinformatics, enzymology, and applied detection technologies have greatly enhanced our understanding of the pathways, the enzymes and the genetic coding for some of the most problematic VOCs produced by cyanobacteria. This has led to the development of tools for rapid and sensitive detection and monitoring for the VOC production at source, and provided the basis for further diagnostics of endogenous and exogenous controls. This review provides an overview of current knowledge of the major cyanobacterial VOCs, the producers, the biochemistry and the genetics and highlight the current applications and further research needs in this area.
To demonstrate the capability of wastewater-based surveillance (WBS) as a tool for detecting potential cases of Japanese Encephalitis Virus (JEV) infection in the community.
In this study, we explore ...the potential of WBS to detect cases of JEV infection by leveraging from an established SARS-CoV-2 wastewater surveillance program. We describe the use of two reverse transcriptase quantitative polymerase chain reaction (RTqPCR) assays targeting JEV to screen archived samples from two wastewater treatment plants (WWTPs). JEV was detected in wastewater samples collected during a timeframe coinciding with a cluster of acute human encephalitis cases, alongside concurrent evidence of JEV detection in mosquito surveillance and the sentinel chicken programs within South Australia's Riverland and Murraylands regions.
Current surveillance measures for JEV encounter multiple constraints, which may miss the early stages of JEV circulation or fail to capture the full extent of transmission. The detection of JEV in wastewater during a disease outbreak highlights the potential WBS has as a complementary layer to existing monitoring efforts forming part of the One Health approach required for optimal disease response and control.
Fermentative hydrogen production (FHP) has received a great R & D interest in recent decades, as it offers a potential means of producing H
2 from a variety of renewable resources, even wastewater ...via a low energy continuous process. Various extracellular metabolites including ethanol, acetate, butyrate and lactate can be produced during the fermentation, building a complex metabolic network of the FHP. Except for the recognition of its complexity, the metabolic flux network has not been well understood. Studies on biochemical reactions and metabolic flux network associated with the FHP in anaerobic fermentation system have only been drawn attention in recent years. This review summarizes the biochemical reactions taking place in the metabolic network of FHP. We discuss how the key operation factors influence metabolism in the FHP process. Recently developed and applied technologies for metabolic flux analysis have been described. Future studies on the metabolic network to enhance fermentative hydrogen production by strict anaerobes are recommended. It is expected that this review can provide useful information in terms of fundamental knowledge and update technology for scientists and research engineers in the field of biological hydrogen production.
Taxonomic uncertainty has had a negative impact on our understanding of the epidemiology of Giardia infections, particularly the role of wild and domestic animals as sources of human infection. The ...lack of morphological criteria for species identification and the failure of cross-infection experiments to unequivocally determine host specificity have largely contributed to this uncertainty. However, over the past ten years, it has been possible not only to demonstrate extensive genetic heterogeneity among Giardia isolates from mammals but also to confirm levels of host specificity that were recognized by early taxonomists when they proposed a series of host-related species that we consider should now be re-established.
Next generation sequencing (NGS) has rapidly become an invaluable tool for the detection, identification and relative quantification of environmental microorganisms. Here, we demonstrate two new 16S ...rDNA primer sets, which are compatible with NGS approaches and are primarily for use in water quality studies. Compared to 16S rRNA gene based universal primers, in silico and experimental analyses demonstrated that the new primers showed increased specificity for the Cyanobacteria and Proteobacteria phyla, allowing increased sensitivity for the detection, identification and relative quantification of toxic bloom-forming microalgae, microbial water quality bioindicators and common pathogens. Significantly, Cyanobacterial and Proteobacterial sequences accounted for ca. 95% of all sequences obtained within NGS runs (when compared to ca. 50% with standard universal NGS primers), providing higher sensitivity and greater phylogenetic resolution of key water quality microbial groups. The increased selectivity of the new primers allow the parallel sequencing of more samples through reduced sequence retrieval levels required to detect target groups, potentially reducing NGS costs by 50% but still guaranteeing optimal coverage and species discrimination.
► Biodegradation of metabolites was affected by temperature and seasonal variations. ► Ease of biodegradability followed the trend: MCLR>CYN>geosmin>saxitoxin. ► A microcystin-degrading bacterium was ...isolated and shown to be closely related to a Sphingopyxis sp. ► Isolate TT25 degraded four microcystin variants within 4h in the presence of copper sulphate.
The fate of multiple cyanobacterial metabolites was assessed in two Australian source waters. The saxitoxins were the only metabolites shown to be non-biodegradable in Myponga Reservoir water, while microcystin-LR (MCLR) and geosmin were biodegradable in this water source. Likewise, cylindrospermopsin (CYN) was shown to be biodegradable in River Murray water. The order of ease of biodegradability followed the trend: MCLR>CYN>geosmin>saxitoxins. Biodegradation of the metabolites was affected by temperature and seasonal variations with more rapid degradation at 24°C and during autumn compared with 14°C and during winter. A microcystin-degrading bacterium was isolated and shown to degrade four microcystin variants within 4h. This bacterium, designated as TT25, was shown to be 99% similar to a Sphingopyxis sp. based on a 16S rRNA gene fragment. Isolate TT25 was shown to contain a homologue of the mlrA gene; the sequence of which was 99% similar to that of a previously reported microcystin-degrader. Furthermore, isolate TT25 could degrade the microcystins in the presence of copper sulphate (0.5mgL−1 as Cu2+) which is advantageous for water authorities dosing such algicides into water bodies to control cyanobacterial blooms.
Escherichia coli is excreted in high numbers from the intestinal tract of humans, other mammals, and birds. Traditionally, it had been thought that E. coli could grow only within human or animal ...hosts and would perish in the environment. Therefore, the presence of E. coli in water has become universally accepted as a key water quality indicator of fecal pollution. However, recent research challenges the assumption that the presence of E. coli in water is always an indicator of fecal contamination, with some types of E. coli having evolved to survive and grow in aquatic environments. These strains can form blooms in water storages, resulting in high E. coli counts even without fecal contamination. Although these bloom-forming strains lack virulence genes and pose little threat to public health, their presence in treated water triggers the same response as fecal-derived E. coli. Yet, little is known about the effectiveness of treatment processes in removing or inactivating them. This study evaluated the effectiveness of current treatment processes to remove bloom-forming strains, in comparison to fecal-derived strains, with conventional coagulation-flocculation-sedimentation and filtration investigated. Second, the effectiveness of current disinfection processes—chlorination, chloramination, and ultraviolet (UV) light to disinfect bloom-forming strains in comparison to fecal-derived strains—was assessed. These experiments showed that the responses of bloom isolates were not significantly different from those of fecal E. coli strains. Therefore, commonly used water treatment and disinfection processes are effective to remove bloom-forming E. coli strains from water.IMPORTANCEThe presence of Escherichia coli in water has long been used globally as a key indicator of fecal pollution and for quantifying water safety. Traditionally, it was believed that E. coli could only thrive within hosts and would perish outside, making its presence in water indicative of fecal contamination. However, recent research has unveiled strains of E. coli capable of surviving and proliferating in aquatic environments, forming blooms even in the absence of fecal contamination. While these bloom-forming strains lack the genes to be pathogenic, their detection in source or drinking water triggers the same response as fecal-derived E. coli. Yet, little is known about the efficacy of treatment processes in removing them. This study evaluated the effectiveness of conventional treatment and disinfection processes in removing bloom-forming strains compared to fecal-derived strains. Results indicate that these commonly used processes are equally effective against both types of E. coli, reassuring that bloom-forming E. coli strains can be eliminated from water.
Following the initial report of the use of SYBR Green I for real-time polymerase chain reaction (PCR) in 1997, little attention has been given to the development of alternative intercalating dyes for ...this application. This is surprising considering the reported limitations of SYBR Green I, which include limited dye stability, dye-dependent PCR inhibition, and selective detection of amplicons during DNA melting curve analysis of multiplex PCRs. We have tested an alternative to SYBR Green I and report the first detailed evaluation of the intercalating dye SYTO9. Our findings demonstrate that SYTO9 produces highly reproducible DNA melting curves over a broader range of dye concentrations than does SYBR Green I, is far less inhibitory to PCR than SYBR Green I, and does not appear to selectively detect particular amplicons. The low inhibition and high melting curve reproducibility of SYTO9 means that it can be readily incorporated into a conventional PCR at a broad range of concentrations, allowing closed tube analysis by DNA melting curve analysis. These features simplify the use of intercalating dyes in real-time PCR and the improved reproducibility of DNA melting curve analysis will make SYTO9 useful in a diagnostic context.
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