Prevalence and antimicrobial susceptibility of Arcobacter species in human stool samples derived from out- and inpatients: the prospective German Arcobacter prevalence study Arcopath

Background: Arcobacter species, particularly A. butzleri, but also A. cryaerophilus constitute emerging pathogens causing gastroenteritis in humans. However, isolation of Arcobacter may often fail during routine diagnostic procedures due to the lack of standard protocols. Furthermore, defined breakpoints for the interpretation of antimicrobial susceptibilities of Arcobacter are missing. Hence, reliable epidemiological data of human Arcobacter infections are scarce and lacking for Germany. We therefore performed a 13-month prospective Arcobacter prevalence study in German patients. Results: A total of 4636 human stool samples was included and Arcobacter spp. were identified from 0.85% of specimens in 3884 outpatients and from 0.40% of specimens in 752 hospitalized patients. Overall, A. butzleri was the most prevalent species (n = 24; 67%), followed by A. cryaerophilus (n = 10; 28%) and A. lanthieri (n = 2; 6%). Whereas A. butzleri, A. cryaerophilus and A. lanthieri were identified in outpatients, only A. butzleri could be isolated from samples of hospitalized patients. Antimicrobial susceptibility testing of Arcobacter isolates revealed high susceptibilities to ciprofloxacin, whereas bimodal distributions of MICs were observed for azithromycin and ampicillin. Conclusions: In summary, Arcobacter including A. butzleri, A. cryaerophilus and A. lanthieri could be isolated in 0.85% of German outpatients and ciprofloxacin rather than other antibiotics might be appropriate for antibiotic treatment of infections. Further epidemiological studies are needed, however, to provide a sufficient risk assessment of Arcobacter infections in humans

Solubilized Chitosan Biopolymers for Sequestration of Organic Acids in Aquatic Environments after Biodegradation in a Constructed Wetland Treatment System

Pristine chitosan was dissolved in two different respective aqueous acids, namely acetic acid (AcA) and hydrochloric acid (HCl). The respective acid solutions were used as media to associate with naphthenic acid fraction compounds (NAFCs) from raw oil sands process water (R-OSPW) contaminants and constructed treatment wetland systems OSPW (CWTS-OSPW) samples. The results revealed selective removal of NAFCs and lyotropic effects due to variable counterion binding of chloride versus acetate with the ionized NAFCs (carboxylate species)

Methyl-donor depletion of head and neck cancer cells in vitro establishes a less aggressive tumour cell phenotype

PURPOSE: DNA methylation plays a fundamental role in the epigenetic control of carcinogenesis and is, in part, influenced by the availability of methyl donors obtained from the diet. In this study, we developed an in-vitro model to investigate whether methyl donor depletion affects the phenotype and gene expression in head and neck squamous cell carcinoma (HNSCC) cells. METHODS: HNSCC cell lines (UD-SCC2 and UPCI-SCC72) were cultured in medium deficient in methionine, folate, and choline or methyl donor complete medium. Cell doubling-time, proliferation, migration, and apoptosis were analysed. The effects of methyl donor depletion on enzymes controlling DNA methylation and the pro-apoptotic factors death-associated protein kinase-1 (DAPK1) and p53 upregulated modulator of apoptosis (PUMA) were examined by quantitative-PCR or immunoblotting. RESULTS: HNSCC cells cultured in methyl donor deplete conditions showed significantly increased cell doubling times, reduced cell proliferation, impaired cell migration, and a dose-dependent increase in apoptosis when compared to cells cultured in complete medium. Methyl donor depletion significantly increased the gene expression of DNMT3a and TET-1, an effect that was reversed upon methyl donor repletion in UD-SCC2 cells. In addition, expression of DAPK1 and PUMA was increased in UD-SCC2 cells cultured in methyl donor deplete compared to complete medium, possibly explaining the observed increase in apoptosis in these cells. CONCLUSION: Taken together, these data show that depleting HNSCC cells of methyl donors reduces the growth and mobility of HNSCC cells, while increasing rates of apoptosis, suggesting that a methyl donor depleted diet may significantly affect the growth of established HNSCC

Assessing and optimizing microbial processes impacting mine reclamation

Microbes influence a wide range of processes, acting as catalysts to accelerate reactions or enable them to occur in a wider range of conditions. In the context of mine reclamation, many aspects are impacted by microbes and understanding their role is critical to making informed decisions, optimizing processes, and improving reclamation success. Examples of microbes affecting mine reclamation processes will be presented, including: passive- and semi-passive water treatment (including metals, metalloids, ammonia, nitrate, acid-rock drainage, heap leach detoxification), soil bioremediation, and revegetation. An overview of the tools currently being used at mines for microbial community profiling will be discussed, spanning from traditional growth-based techniques, through to modern day standardized genetic community profiling based on DNA-sequencing. This information will be provided in the context of how they have been used to guide and optimize mine reclamation strategies.Non UBCUnreviewedOthe

Transcriptional activity and role of plasmids of <em>Lactobacillus brevis </em>BSO 464 and <em>Pediococcus claussenii </em>ATCC BAA-344T during growth in the presence of hops

Whole-transcriptome analysis was performed on beer-spoilage organisms Lactobacillus brevis BSO 464 (Lb464) and Pediococcus claussenii ATCC BAA-344T (Pc344) when grown in growth-limiting concentrations of hop extract. This was done to delineate the hops-specific component of the total transcriptional response for these bacteria when growing in beer. The transcriptome of highly hop-tolerant isolate Lb464 had fewer genes with differential expression in response to a stronger challenge (i.e., higher bitterness units) of hop extract than did Pc344, highlighting the variable nature of hop-tolerance in beer-spoilage-related lactic acid bacteria. As Lb464 can grow in pressurized/gassed beer and Pc344 cannot, this indicates that the genetic and physiological response to hops alone does not dictate the overall beer-spoilage virulence of an isolate. The general response to hops in both isolates involves pathways of acid tolerance and intracellular pH homeostasis, with glutamate and citrate metabolism, and biogenic amine metabolism as additional major responses to the presence of hop extract by Lb464 and Pc344, respectively. A Pc344 chromosomal ABC transporter (PECL_1630) was more strongly expressed than the plasmid-located, hop-tolerance ABC transporter horA. PECL_1630 is suggested to be involved in import of ATP into the cell, potentially assisting the total bacterial community when facing hop stress. This transporter is found in other beer-related P. claussenii suggesting a putative species-specific beer-spoilage-related genetic marker. Lb464 and Pc344 each contain eight plasmids and transcription from almost all occurs in response to both hops and beer. However, as evident by both transcriptional analysis and plasmid variant analysis, each bacterium harbors one plasmid that is critical for responding to hops and beer stress. For both bacteria, complex transcriptional regulation and cooperation between chromosomal and plasmid-based genes occurs in response to the growth challenges imposed by hops or beer

Volcanic reconstruction and geochemistry of the Powderhouse formation in the Paleoproterozoic VMS-hosting Chisel sequence, Snow Lake, Manitoba, Canada

The Powderhouse formation of the Paleoproterozoic Snow Lake arc assemblage comprises the stratigraphic footwall to six volcanogenic massive sulfide (VMS) deposits at Snow Lake, Manitoba, Canada. It is interpreted to be a product of voluminous pyroclastic eruptions and concomitant subsidence followed by a period of relative volcanic quiescence that was dominated by suspension sedimentation, the reworking of previously deposited pyroclastic units by debris flows and bottom currents, and localized emplacement of rhyolite domes. The rhyolite domes are spatially associated with the Chisel, Chisel North, Lost, Ghost, Photo, and Lalor deposits. The Chisel, Lalor, and Lost members compose the Powderhouse formation and are subdivided into 13 lithologically distinct lithofacies, which allows, for the first time, correlation of stratigraphy between the South Chisel basin and Lalor areas, critical in predicting the location of largely stratiform VMS deposits. The Chisel and Lalor members contain lithofacies and bedforms that are characteristic of emplacement by subaqueous pyroclastic mass flows and concomitant subsidence. The Chisel member also contains coarse volcaniclastic breccias emplaced by mass debris flows derived from movement along fault scarps following early pyroclastic eruptions, and during continued subsidence. The Lost member consists of lithofacies deposited by mass flows generated from faults scraps during continued subsidence, but also contains lithofacies reworked by bottom currents, those deposited by suspension sedimentation, and, locally, coherent rhyolite. The Lost member represents a time stratigraphic interval, the “ore interval”, that marks contemporaneous rhyolite dome emplacement, VMS formation, and a hiatus in explosive volcanism.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Assessment of the Huckleberry Mine site for potential passive or semi-passive acid rock drainage treatment options

Passive water treatment is often sought as a component of long-term mine closure scenarios, as it promotes relatively self-sustaining beneficial conditions for impacted water management at low maintenance and operational costs. However, owing to the biogeochemical nature of these technologies, a site-specific phased approach is necessary for successful implementation. Huckleberry Mine was evaluated for the viability of passive water treatment technologies to address potential future acid rock drainage (ARD)-impacted waters containing constituents such as aluminum and copper. Natural wetlands, seepage collection ponds, and ARD-impacted areas were assessed using genetic microbial community profiling, paired with traditional growth-based microbial characterization and quantification. This information was evaluated in the context of water chemistry, treatment objectives, and biogeochemical processes to develop a conceptual treatment train to semi-passively treat water. A phased program was then developed to determine if each step of the treatment train could address its goals individually, or if it would be best implemented to reduce costs associated with an equivalent active water treatment step.Non UBCUnreviewedOthe

Bench- and field-scale trials of in-situ biological treatment of cadmium and zinc in flooded mine workings, Northern Canada

Passive and semi-passive treatment of underground mine waters provides a low cost, low maintenance alternative to active treatment; however, such non-traditional approaches often require pilot testwork to ensure regulator and stakeholder acceptance. Here we describe two examples of laboratory- and field-based studies of in-situ treatment of mine workings water. To support closure planning of an unnamed mine in British Columbia, 200 L mesocosms comprising synthetic mine water (SMW), waste rock, and cemented tailings that will backfill the mine at closure were prepared. These were amended with glycerol or ethanol, resulting in sulphate-reducing conditions under which constituents of concern (COCs) such as antimony (average initial concentration of 1.9 mg/L), cadmium (0.088 mg/L), selenium (0.039 mg/L), and zinc (5.0 mg/L) exhibited marked peak removal (>99%, >99%, 99%, and 95%, respectively relative to control trial). Sustained treatment below the discharge standards was achieved by the end of the 26-week experiment. Glycerol-amended trials exhibited the greatest treatment, likely related to the higher abundance and diversity of sulphide-producing and selenium-reducing bacteria observed in these trials. At the historical Silver King mine (Yukon), in-situ treatment has been ongoing since October 2014 and provides a field-scale exemplar for this treatment approach in a remote, cold climate setting. Molasses injection to the flooded underground mine workings resulted in rapid removal (>90%) of COCs cadmium and zinc. Multiple injection events in the first year of operation created sustained sulphate-reducing conditions with an attendant shift in the microbial community structure towards the naturally occurring sulphide-producing bacteria key to the treatment process. Following such initial ‘commissioning’, biennial methanol injections have maintained metal concentrations in the adit discharge below effluent quality standards since 2016. Such laboratory- and field-based demonstrations provide important information regarding the inclusion of in-situ treatment in the toolbox of long-term treatment options for mine closure.Non UBCUnreviewedOthe

Assessment of the Mount Polley Mine site for potential passive or semi-passive treatment options

Passive water treatment is often sought as a component of long-term mine closure management. Passive water treatment promotes relatively self-sustaining conditions for the management of mine impacted water, with outcomes often being low maintenance and operational costs. However, owing to the sensitive biogeochemical nature of these technologies, a site-specific phased approach is necessary for evaluating passive treatment as a component of mine closure management, and ultimately, its successful implementation. The Mount Polley Mine (the “Mine”) was evaluated for the viability of constructed wetland treatment systems (CWTSs) as part of their long-term water management plan. A site assessment was conducted, which identified potential plant species for use in a CWTS, and evaluated the water, substrates, and plants in the context of a CWTS. Genetic microbial community profiling was used to assess natural wetlands, and components of the water management infrastructure at the Mine, and was paired with traditional growth-based microbial characterization and quantification. This information was evaluated in the context of water chemistry, treatment objectives, and biogeochemical processes to assess the feasibility for semi-passively or passively treating Mine water. Upon assessment of the natural treatment capacity at the Mine, natural conditions and processes were identified that could potentially benefit water quality.Non UBCUnreviewedOthe