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1.
Crit Rev Microbiol ; 43(2): 210-237, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27822973

RESUMO

Volatile Organic Sulfur Compounds (VOSCs) are instrumental in global S-cycling and greenhouse gas production. VOSCs occur across a diversity of inland waters, and with widespread eutrophication and climate change, are increasingly linked with malodours in organic-rich waterbodies and drinking-water supplies. Compared with marine systems, the role of VOSCs in biogeochemical processes is far less well characterized for inland waters, and often involves different physicochemical and biological processes. This review provides an updated synthesis of VOSCs in inland waters, focusing on compounds known to cause malodours. We examine the major limnological and biochemical processes involved in the formation and degradation of alkylthiols, dialkylsulfides, dialkylpolysulfides, and other organosulfur compounds under different oxygen, salinity and mixing regimes, and key phototropic and heterotrophic microbial producers and degraders (bacteria, cyanobacteria, and algae) in these environs. The data show VOSC levels which vary significantly, sometimes far exceeding human odor thresholds, generated by a diversity of biota, biochemical pathways, enzymes and precursors. We also draw attention to major issues in sampling and analytical artifacts which bias and preclude comparisons among studies, and highlight significant knowledge gaps that need addressing with careful, appropriate methods to provide a more robust understanding of the potential effects of continued global development.


Assuntos
Compostos de Enxofre/química , Compostos de Enxofre/metabolismo , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/metabolismo , Microbiologia da Água , Bactérias/metabolismo , Fenômenos Biológicos , Fenômenos Químicos , Clorófitas/metabolismo
2.
Environ Sci Technol ; 50(2): 604-15, 2016 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-26654276

RESUMO

Although toxic cyanobacterial blooms in western Lake Erie threaten drinking water supplies and are promoted by nutrient loading, the precise nutrient regime that selects specific cyanobacteria populations is poorly understood. Here, we assess shifts in cyanobacterial abundances and global gene-expression patterns in response to natural and manipulated gradients in nitrogen and phosphorus to identify gene pathways that facilitate dominance by different cyanobacteria. Gradients in soluble reactive phosphorus shaped cyanobacterial communities and elicited the largest transcriptomic responses. Under high-P conditions (closest to the mouth of the Maumee River), Anabaena and Planktothrix were the dominant cyanobacterial populations, and experimental P and ammonium enrichment promoted nitrogen fixation gene (nifH) expression in Anabaena. For Microcystis, experimental additions of P up-regulated genes involved in phage defense, genomic rearrangement, and nitrogen acquisition but led to lower abundances. Within offshore, low-P regions of the western basin of Lake Erie, Microcystis up-regulated genes associated with P scavenging (pstSCAB, phoX) and dominated cyanobacterial communities. Experimental additions of ammonium and urea did not alter Microcystis abundances but did up-regulate protease inhibitors (aer and mcn gene sets) and microcystin synthetase genes (mcy), with urea enrichment yielding significant increases in microcystin concentrations. Our findings suggest that management plans that reduce P loads alone may not significantly reduce the risk of cyanobacterial blooms in western Lake Erie but rather may promote a shift among cyanobacterial populations (Microcystis, Anabaena, and Planktothrix) toward a greater dominance by toxic strains of Microcystis.


Assuntos
Proteínas de Bactérias/genética , Cianobactérias/fisiologia , Ecossistema , Nitrogênio/metabolismo , Fósforo/metabolismo , Proteínas de Bactérias/metabolismo , Cianobactérias/genética , Lagos/microbiologia , Ohio , Análise de Sequência de DNA , Transcriptoma
3.
Environ Sci Technol ; 49(12): 7197-207, 2015 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-25992592

RESUMO

Sandusky Bay experiences annual toxic cyanobacterial blooms dominated by Planktothrix agardhii/suspensa. To further understand the environmental drivers of these events, we evaluated changes in the growth response and toxicity of the Planktothrix-dominated blooms to nutrient amendments with orthophosphate (PO4) and inorganic and organic forms of dissolved nitrogen (N; ammonium (NH4), nitrate (NO3) and urea) over the bloom season (June - October). We complemented these with a metagenomic analysis of the planktonic microbial community. Our results showed that bloom growth and microcystin (MC) concentrations responded more frequently to additions of dissolved N than PO4, and that the dual addition of NH4 + PO4 and Urea + PO4 yielded the highest MC concentrations in 54% of experiments. Metagenomic analysis confirmed that P. agardhii/suspensa was the primary MC producer. The phylogenetic distribution of nifH revealed that both heterocystous cyanobacteria and heterotrophic proteobacteria had the genetic potential for N2 fixation in Sandusky Bay. These results suggest that as best management practices are developed for P reductions in Sandusky Bay, managers must be aware of the negative implications of not managing N loading into this system as N may significantly impact cyanobacterial bloom size and toxicity.


Assuntos
Baías/microbiologia , Eutrofização , Lagos/microbiologia , Nitrogênio/análise , Fósforo/análise , Fitoplâncton/crescimento & desenvolvimento , Biomassa , Cianobactérias/crescimento & desenvolvimento , Geografia , Fixação de Nitrogênio , Chuva , Estações do Ano , Qualidade da Água
4.
J Clin Psychopharmacol ; 34(4): 426-34, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24781441

RESUMO

We compared long-term treatment effectiveness of monthly olanzapine long-acting injection (LAI) with that of oral olanzapine. Outpatients with 2 or more episodes of psychotic worsening in the past 24 months with Positive and Negative Syndrome Scale total score of lower than 70 were randomized to 405 mg/4 weeks of olanzapine LAI (n = 264) or 10 mg/d of oral olanzapine (n = 260) for 2 years of open-label treatment. Dosing thereafter was flexible (150-405 mg/4 weeks of LAI vs 5-20 mg/d of oral). Primary outcome was time to all-cause discontinuation. At baseline, patients were clinically stable (mean Positive and Negative Syndrome Scale total score of 57). Seventeen percent of patients had been psychiatrically hospitalized in the previous 6 months, and 4.6% were rated nonadherent in the month before study entry. The groups did not differ significantly in median time to all-cause discontinuation (645 days for LAI, 678 days for oral; P = 0.61), discontinuation rate (53.8% for LAI, 51.2% for oral; P = 0.60), or relapse rate (20.1% for LAI, 18.5% for oral; P = 0.66). Postbaseline psychiatric hospitalization rate was low for both groups (7.6% for LAI, 9.2% for oral), but mean hospitalization duration was significantly longer for oral patients (1.80 days [20 for those hospitalized] vs 0.43 days [6 for those hospitalized], P = 0.02). There were no clinically significant group differences in adverse events or safety measures. No post-injection delirium/sedation syndrome events occurred. In conclusion, olanzapine LAI and oral olanzapine were similarly effective and well tolerated for up to 2 years of treatment in patients with schizophrenia. Treatment discontinuation for olanzapine LAI was similar to that of oral olanzapine, despite the 3-hour post-injection observation period and other precautionary procedures related to risk of post-injection delirium/sedation syndrome.


Assuntos
Assistência Ambulatorial/métodos , Antipsicóticos/administração & dosagem , Benzodiazepinas/administração & dosagem , Esquizofrenia/diagnóstico , Esquizofrenia/tratamento farmacológico , Administração Oral , Adulto , Preparações de Ação Retardada/administração & dosagem , Feminino , Humanos , Injeções Intramusculares , Masculino , Pessoa de Meia-Idade , Olanzapina , Satisfação do Paciente , Fatores de Tempo , Resultado do Tratamento
5.
Harmful Algae ; 130: 102527, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38061818

RESUMO

Microcystis species not only produce toxic cyanobacterial blooms, but can be a significant source of taste and odour. Previous studies have associated foul-smelling volatile organic sulfur compounds (VOSCs) with Microcystis blooms, but have largely attributed these compounds to bacterial bloom decomposition. However, earlier reports of the production of isopropylthio compounds by several Microcystis strains suggests that these cyanobacteria may themselves be a source of these VOSCs. Sulphur compounds have been shown to play important semiochemical roles in algal cell protection and grazer interactions in marine systems, but little is known about the production and chemical ecology of freshwater cyanobacterial VOSCs. To address this knowledge gap, we undertook the first detailed investigation of the biochemistry, ecophysiology and semiochemistry of these compounds and their production by Microcystis, and tested the hypothesis that they act as multifunctional semiochemicals in processes related to cell protection and grazer defence. Using short-term incubations and an adapted headspace-GC-MS technique, we investigated VOSC production by axenic and non-axenic strains, and verified that isopropylthio compounds are in fact produced by these cyanobacteria, identifying 5 isopropyl moiety-containing VOSCs (isopropylthiol (ISH), isopropylmethyl sulfide, isopropyl methyl disulfide, diisopropyl disulfide (ISSI) and diisopropyl trisulfide) as well as methanethiol in three strains. Further studies with the axenic strain Microcystis PCC 7806 using different light regimes, metabolic inhibitors (sodium azide, DCMU), the antioxidant enzyme catalase and stable labelled precursors (hydrogencarbonate, acetates and sulfate) demonstrated that ISH is a true exo-metabolite, synthesized via the acetate pathway. It is actively produced and continuously excreted by the cyanobacteria during growth, with minimal internal storage or post-lysis catalytic generation. The molar ratios of the redox pair ISH/ISSI are not directly involved in the photosynthetic and respiratory electron transport chains, but dependant on the redox state of the cell - likely mediated by reactive oxygen species (ROS), as shown by a marked effect of catalase. These results, along with toxicological and behavioural assays using the two aquatic invertebrates Thamnocephalus platyurus and Daphnia magna indicate that ISH plays multiple important physiological and ecological roles. It acts as an effective antioxidant against high ROS levels, as often experienced in surface blooms, it elicits avoidance-related behavioural responses in grazer communities and at high levels, it can be toxic to some invertebrates.


Assuntos
Cianobactérias , Microcystis , Microcystis/fisiologia , Catalase/metabolismo , Antioxidantes , Espécies Reativas de Oxigênio/metabolismo , Cianobactérias/fisiologia
6.
Front Microbiol ; 14: 1073753, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36846788

RESUMO

Lake Erie is subject to recurring events of cyanobacterial harmful algal blooms (cHABs), but measures of nutrients and total phytoplankton biomass seem to be poor predictors of cHABs when taken individually. A more integrated approach at the watershed scale may improve our understanding of the conditions that lead to bloom formation, such as assessing the physico-chemical and biological factors that influence the lake microbial community, as well as identifying the linkages between Lake Erie and the surrounding watershed. Within the scope of the Government of Canada's Genomics Research and Development Initiative (GRDI) Ecobiomics project, we used high-throughput sequencing of the 16S rRNA gene to characterize the spatio-temporal variability of the aquatic microbiome in the Thames River-Lake St. Clair-Detroit River-Lake Erie aquatic corridor. We found that the aquatic microbiome was structured along the flow path and influenced mainly by higher nutrient concentrations in the Thames River, and higher temperature and pH downstream in Lake St. Clair and Lake Erie. The same dominant bacterial phyla were detected along the water continuum, changing only in relative abundance. At finer taxonomical level, however, there was a clear shift in the cyanobacterial community, with Planktothrix dominating in the Thames River and Microcystis and Synechococcus in Lake St. Clair and Lake Erie. Mantel correlations highlighted the importance of geographic distance in shaping the microbial community structure. The fact that a high proportion of microbial sequences found in the Western Basin of Lake Erie were also identified in the Thames River, indicated a high degree of connectivity and dispersal within the system, where mass effect induced by passive transport play an important role in microbial community assembly. Nevertheless, some cyanobacterial amplicon sequence variants (ASVs) related to Microcystis, representing less than 0.1% of relative abundance in the upstream Thames River, became dominant in Lake St. Clair and Erie, suggesting selection of those ASVs based on the lake conditions. Their extremely low relative abundances in the Thames suggest additional sources are likely to contribute to the rapid development of summer and fall blooms in the Western Basin of Lake Erie. Collectively, these results, which can be applied to other watersheds, improve our understanding of the factors influencing aquatic microbial community assembly and provide new perspectives on how to better understand the occurrence of cHABs in Lake Erie and elsewhere.

7.
BMC Psychiatry ; 11: 28, 2011 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-21324135

RESUMO

BACKGROUND: In a recently published 24-week maintenance study of olanzapine long-acting injection (LAI) in schizophrenia (Kane et al., 2010), apparent dose-associated changes were noted in both efficacy and safety parameters. To help clinicians balance safety and efficacy when choosing a dose of olanzapine LAI, we further studied these changes. METHODS: Outpatients with schizophrenia who had maintained stability on open-label oral olanzapine for 4 to 8 weeks were randomly assigned to "low" (150 mg/2 weeks; N = 140), "medium" (405 mg/4 weeks; N = 318), or "high" (300 mg/2 weeks; N = 141) dosages of olanzapine LAI for 24 weeks. Potential relationships between dose and several safety or efficacy measures were examined via regression analysis, the Jonckheere-Terpstra test (continuous data), or the Cochran-Armitage test (categorical data). RESULTS: Safety parameters statistically significantly related to dose were mean weight change (low: +0.67 [SD = 4.38], medium: +0.89 [SD = 3.87], high: +1.70 [SD = 4.14] kg, p = .024; effect size [ES] = 0.264 high vs. low dose), mean change in prolactin (low: -5.61 [SD = 12.49], medium: -2.76 [SD = 19.02]), high: +3.58 [SD = 33.78] µg/L, p = .001; ES = 0.410 high vs. low dose), fasting triglycerides change from normal at baseline to high (low: 3.2%, medium: 6.0%, high: 18.9%, p = .001; NNT = 7 high vs. low dose) and fasting high-density lipoprotein cholesterol change from normal at baseline to low (low: 13.8%, medium: 19.6%, high: 30.7%, p = .019; NNT = 6 high vs. low dose). Efficacy measures significantly related to dose included Positive and Negative Syndrome Scale total score mean change (low: +2.66 [SD = 14.95], medium: -0.09 [SD = 13.47], high: -2.19 [SD = 13.11], p <.01; ES = 0.356 high vs. low dose), relapse rate (low: 16%, medium: 10%, high: 5%, p = .003; NNT = 9 high vs. low dose), all-cause discontinuation rate (low: 36%, medium: 30%, high: 24%, p = .037; NNT = 9 high vs. low dose), and rate of discontinuation due to efficacy-related reasons (low: 20%, medium: 14%, high: 6%, p <.001). Time to all-cause discontinuation (p = .035) and time to relapse (p = .005) were also significantly related to dose. CONCLUSIONS: Analyses of several safety and efficacy parameters revealed significant associations with dose of olanzapine LAI, with the highest dose generally showing greater efficacy as well as greater adverse changes in metabolic safety measures. When considering olanzapine LAI, as with all antipsychotics, it is important to carefully consider the potential benefits and risks for an individual patient. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00088491.


Assuntos
Antipsicóticos/uso terapêutico , Benzodiazepinas/uso terapêutico , Esquizofrenia/tratamento farmacológico , Antipsicóticos/administração & dosagem , Antipsicóticos/efeitos adversos , Benzodiazepinas/administração & dosagem , Benzodiazepinas/efeitos adversos , Relação Dose-Resposta a Droga , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Olanzapina , Análise de Regressão , Resultado do Tratamento
8.
Toxins (Basel) ; 13(7)2021 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-34199141

RESUMO

The understanding of deep chlorophyll layers (DCLs) in the Great Lakes-largely reported as a mix of picoplankton and mixotrophic nanoflagellates-is predominantly based on studies of deep (>30 m), offshore locations. Here, we document and characterize nearshore DCLs from two meso-oligotrophic embayments, Twelve Mile Bay (TMB) and South Bay (SB), along eastern Georgian Bay, Lake Huron (Ontario, Canada) in 2014, 2015, and 2018. Both embayments showed the annual formation of DCLs, present as dense, thin, metalimnetic plates dominated by the large, potentially toxic, and bloom-forming cyanobacteria Planktothrix cf. isothrix. The contribution of P. cf. isothrix to the deep-living total biomass (TB) increased as thermal stratification progressed over the ice-free season, reaching 40% in TMB (0.6 mg/L at 9.5 m) and 65% in South Bay (3.5 mg/L at 7.5 m) in 2015. The euphotic zone in each embayment extended down past the mixed layer, into the nutrient-enriched hypoxic hypolimnia, consistent with other studies of similar systems with DCLs. The co-occurrence of the metal-oxidizing bacteria Leptothrix spp. and bactivorous flagellates within the metalimnetic DCLs suggests that the microbial loop plays an important role in recycling nutrients within these layers, particularly phosphate (PO4) and iron (Fe). Samples taken through the water column in both embayments showed measurable concentrations of the cyanobacterial toxins microcystins (max. 0.4 µg/L) and the other bioactive metabolites anabaenopeptins (max. ~7 µg/L) and cyanopeptolins (max. 1 ng/L), along with the corresponding genes (max. in 2018). These oligopeptides are known to act as metabolic inhibitors (e.g., in chemical defence against grazers, parasites) and allow a competitive advantage. In TMB, the 2018 peaks in these oligopeptides and genes coincided with the P. cf. isothrix DCLs, suggesting this species as the main source. Our data indicate that intersecting physicochemical gradients of light and nutrient-enriched hypoxic hypolimnia are key factors in supporting DCLs in TMB and SB. Microbial activity and allelopathy may also influence DCL community structure and function, and require further investigation, particularly related to the dominance of potentially toxigenic species such as P. cf. isothrix.


Assuntos
Toxinas Bacterianas/análise , Baías/análise , Baías/microbiologia , Lagos/análise , Lagos/microbiologia , Poluentes da Água/análise , Biomassa , Clorofila , Monitoramento Ambiental , Luz , Metais Pesados/análise , Compostos de Nitrogênio/análise , Ontário , Oxigênio , Fosfatos/análise , Planktothrix
9.
J Photochem Photobiol B ; 219: 112186, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33892284

RESUMO

Harmful algal blooms in inland waters are widely linked to excess phosphorus (P) loading, but increasing evidence shows that their growth and formation can also be influenced by nitrogen (N) and iron (Fe). Deficiency in N, P, and Fe differentially affects cellular photosystems and is manifested as changes in photosynthetic yield (Fv/Fm). While Fv/Fm has been increasingly used as a rapid and convenient in situ gauge of nutrient deficiency, there are few rigorous comparisons of instrument sensitivity and ability to resolve specific nutrient stresses. This study evaluated the application of Fv/Fm to cyanobacteria using controlled experiments on a single isolate and tested three hypotheses: i) single Fv/Fm measurements taken with different PAM fluorometers can distinguish among limitation by different nutrients, ii) measurements of Fv/Fm made by the addition of DCMU are comparable to PAM fluorometers, and iii) dark adaptation is not necessary for reliable Fv/Fm measurements. We compared Fv/Fm taken from the bloom-forming Microcystis aeruginosa (UTEX LB 3037) grown in nutrient-replete treatment (R) and N-, P-, and Fe-limited treatments (LN, LP, LFe, respectively), using three pulse-amplitude modulated (PAM) fluorometers and the chemical photosynthesis inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), and evaluated the effects of dark adaptation prior to PAM measurement. There were significant differences in Fv/Fm estimates among PAM fluorometers for light- versus dark-adapted cell suspensions over the whole experiment (21 days), which were all significantly higher than the DCMU-based measurements. However, dark adaptation had no effect on Fv/Fm when comparing PAM-based values across a single nutrient treatment. All Fv/Fm methods could distinguish LN and LP from R and LFe treatments but none were able to resolve LFe from R, or LN from LP cultures. These results indicated that for most PAM applications, dark adaptation is not necessary, and furthermore that single measurements of Fv/Fm do not provide a robust measurement of nutrient limitation in Microcystis aeruginosa UTEX LB 3037, and potentially other, common freshwater cyanobacteria.


Assuntos
Fluorometria/métodos , Microcystis/metabolismo , Nutrientes/química , Clorofila/química , Diurona/farmacologia , Proliferação Nociva de Algas/efeitos dos fármacos , Proliferação Nociva de Algas/efeitos da radiação , Ferro/química , Luz , Microcystis/crescimento & desenvolvimento , Microcystis/efeitos da radiação , Nitrogênio/química , Nutrientes/farmacologia , Fósforo/química , Fotossíntese/efeitos dos fármacos , Fotossíntese/efeitos da radiação
10.
J Chem Ecol ; 36(12): 1387-97, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21072572

RESUMO

ß-Cyclocitral is often present in eutrophic waters and is a well known source of airborne and drinking water malodor, but its production and functional ecology are unresolved. This volatile organic compound (VOC) is derived from the catalytic breakdown of ß-carotene, and evidence indicates that it is produced by the activation of a specific carotene oxygenase by all species of the bloom-forming cyanobacterium Microcystis. Previous work has shown that ß-cyclocitral affects grazer behavior, but the nature of this interaction and its influence on predator-prey dynamics was unresolved. The present study combined analytical and behavioral studies to evaluate this interaction by using Microcystis NRC-1 and Daphnia magna. Results showed that ß-cyclocitral was undetectable in live Microcystis cells, or present only at extremely low concentrations (2.6 amol /cell). In contrast, cell rupture activated a rapid carotene oxygenase reaction, which produced high amounts (77 ± 5.5 amol ß-cyclocitral/cell), corresponding to a calculated maximum intracellular concentration of 2.2 mM. The behavioral response of Daphnia magna to ß-cyclocitral was evaluated in a bbe© Daphnia toximeter, where ß-cyclocitral treatments induced a marked increase in swimming velocity. Acclimation took place within a few minutes, when Daphnia returned to normal swimming velocity while still exposed to ß-cyclocitral. The minimum VOC concentration (odor threshold) that elicited a significant grazer response was 750 nM ß-cyclocitral, some 2,900 times lower than the per capita yield of a growing Microcystis cell after activation. Under natural conditions, initial grazer-related or other mode of cell rupture would lead to the development of a robust ß-cyclocitral microzone around Microcystis colonies, thus acting as both a powerful repellent and signal of poor quality food to grazers.


Assuntos
Daphnia/efeitos dos fármacos , Microcystis/metabolismo , Aldeídos/análise , Aldeídos/farmacologia , Animais , Carotenoides/análise , Daphnia/fisiologia , Diterpenos/farmacologia , Reação de Fuga , Comportamento Alimentar/efeitos dos fármacos , Odorantes/análise , Natação , Vitamina A/análogos & derivados , beta-Caroteno 15,15'-Mono-Oxigenase/metabolismo
11.
Environ Monit Assess ; 149(1-4): 201-11, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18253851

RESUMO

Streams and lakes in rocky environments are especially susceptible to nutrient loading from wastewater-affected groundwater plumes. However, the use of invasive techniques such as drilling wells, installing piezometers or seepage meters, to detect and characterize these plumes can be prohibitive. In this work, we report on the use of four non-intrusive methods for this purpose at a site in the Rocky Mountains. The methods included non-invasive geophysical surveys of subsurface electrical conductivity (EC), in-situ EC measurement of discharging groundwater at the lake-sediment interface, shoreline water sampling and nutrient analysis, and shoreline periphyton sampling and analysis of biomass and taxa relative abundance. The geophysical surveys were able to detect and delineate two high-EC plumes, with capacitively coupled ERI (OhmMapper) providing detailed two-dimensional images. In situ measurements at the suspected discharge locations confirmed the presence of high-EC water in the two plumes and corroborated their spatial extent. The nutrient and periphyton results showed that only one of the two high-EC plumes posed a current eutrophication threat, with elevated nitrogen and phosphorus levels, high localized periphyton biomass and major shifts in taxonomic composition to taxa that are commonly associated with anthropogenic nutrient loading. This study highlights the need to use non-intrusive methods in combination, with geophysical and water EC-based methods used for initial detection of wastewater-affected groundwater plumes, and nutrient or periphyton sampling used to characterize their ecological effects.


Assuntos
Monitoramento Ambiental/métodos , Água Doce/química , Esgotos/química , Movimentos da Água , Poluentes Químicos da Água/análise , Abastecimento de Água , Animais , Colúmbia Britânica , Técnicas Eletroquímicas , Sedimentos Geológicos/química , Humanos
12.
Harmful Algae ; 87: 101624, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31349881

RESUMO

Over the past two decades there has been a re-emergence of regular harmful algal blooms in Lake Erie due to increasing phosphorus loading, mainly from non-point agricultural sources. The Canadian and United States governments have jointly agreed to reduce phosphorus loadings to the lake in order to control the extent and severity of the blooms. Citizens on both sides of the border face a number of economic costs, both market and non-market, as a result of the blooms. This study values these costs for the Canadian portion of the Lake Erie basin economy using standard economic approaches that are widely applied within the world of cost-benefit analysis. The results suggest that algal blooms will impose equivalent annual costs equal to $272 million in 2015 prices over a 30-year period if left unchecked. The largest market costs will be imposed on the tourism industry ($110 million in equivalent annual costs) and the largest non-market costs will be borne by recreational users and those who place inherent value on the lake's quality ($115 million in equivalent annual costs). Management action to reduce phosphorus loadings is found to be justified on economic grounds if the 30-year net present value of the reduction program is less than $1294 million (2015 Canadian dollars).


Assuntos
Proliferação Nociva de Algas , Lagos , Canadá , Fósforo , Estados Unidos
13.
Toxins (Basel) ; 11(10)2019 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-31614508

RESUMO

Lake Winnipeg (Manitoba, Canada), the world's 12th largest lake by area, is host to yearly cyanobacterial harmful algal blooms (cHABs) dominated by Aphanizomenon and Dolichospermum. cHABs in Lake Winnipeg are primarily a result of eutrophication but may be exacerbated by the recent introduction of dreissenid mussels. Through multiple methods to monitor the potential for toxin production in Lake Winnipeg in conjunction with environmental measures, this study defined the baseline composition of a Lake Winnipeg cHAB to measure potential changes because of dreissenid colonization. Surface water samples were collected in 2013 from 23 sites during summer and from 18 sites in fall. Genetic data and mass spectrometry cyanotoxin profiles identified microcystins (MC) as the most abundant cyanotoxin across all stations, with MC concentrations highest in the north basin. In the fall, mcyA genes were sequenced to determine which species had the potential to produce MCs, and 12 of the 18 sites were a mix of both Planktothrix and Microcystis. Current blooms in Lake Winnipeg produce low levels of MCs, but the capacity to produce cyanotoxins is widespread across both basins. If dreissenid mussels continue to colonize Lake Winnipeg, a shift in physicochemical properties of the lake because of faster water column clearance rates may yield more toxic blooms potentially dominated by microcystin producers.


Assuntos
Toxinas Bacterianas/análise , Cianobactérias , Microcistinas/análise , Saxitoxina/análise , Uracila/análogos & derivados , Poluentes da Água/análise , Alcaloides , Animais , Toxinas Bacterianas/genética , Bivalves , Cianobactérias/genética , Toxinas de Cianobactérias , Monitoramento Ambiental , Proliferação Nociva de Algas , Lagos/microbiologia , Manitoba , Microcistinas/genética , Filogenia , Saxitoxina/genética , Uracila/análise
14.
Harmful Algae ; 77: 93-107, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-30005805

RESUMO

In order to better understand the relationships among current Nostocales cyanobacterial blooms, eight genomes were sequenced from cultured isolates or from environmental metagenomes of recent planktonic Nostocales blooms. Phylogenomic analysis of publicly available sequences placed the new genomes among a group of 15 genomes from four continents in a distinct ADA clade (Anabaena/Dolichospermum/Aphanizomenon) within the Nostocales. This clade contains four species-level groups, two of which include members with both Anabaena-like and Aphanizomenon flos-aquae-like morphology. The genomes contain many repetitive genetic elements and a sizable pangenome, in which ABC-type transporters are highly represented. Alongside common core genes for photosynthesis, the differentiation of N2-fixing heterocysts, and the uptake and incorporation of the major nutrients P, N and S, we identified several gene pathways in the pangenome that may contribute to niche partitioning. Genes for problematic secondary metabolites-cyanotoxins and taste-and-odor compounds-were sporadically present, as were other polyketide synthase (PKS) and nonribosomal peptide synthetase (NRPS) gene clusters. By contrast, genes predicted to encode the ribosomally generated bacteriocin peptides were found in all genomes.


Assuntos
Cianobactérias/classificação , Genoma Bacteriano , Proteínas de Bactérias/análise , Cianobactérias/genética , Proliferação Nociva de Algas , Filogenia
15.
Biol Psychiatry ; 61(5): 713-9, 2007 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-16996485

RESUMO

BACKGROUND: We systematically examined potential aggression/hostility-related events in a meta-analysis of acute clinical trials of atomoxetine for attention-deficit/hyperactivity disorder (ADHD). METHODS: Pediatric patients from 14 trials of atomoxetine were subdivided into a placebo-controlled (atomoxetine n = 1308, placebo n = 806) or active comparator databases (atomoxetine n = 566, methylphenidate n = 472). A third database comprised adult patients from placebo-controlled studies (atomoxetine n = 541, placebo n = 405). A computerized search of adverse events and comments identified patients with potential aggression/hostility events. Mantel-Haenszel incidence differences (MHID) were calculated. RESULTS: In the placebo-controlled database, we observed 21 atomoxetine and 9 placebo patients with reported aggression/hostility events, MHID of .6% (95% confidence interval [CI]: -.4, 1.7). In the active comparator database, there were seven events in atomoxetine and four in methylphenidate patients, MHID = .2% (95% CI: -1.0,1.3). In the adult database, there were no events in 0 atomoxetine and one placebo patient, MHID = -.3% (95% CI: -.8, .2). CONCLUSIONS: Aggression/hostility-related events occurred in less than 2% of patients and were more frequent in pediatric patients treated with atomoxetine versus placebo (risk ratio of 1.33; not statistically significant). The risk of aggression/hostility events was similar in patients treated with atomoxetine or methylphenidate.


Assuntos
Inibidores da Captação Adrenérgica/uso terapêutico , Agressão/efeitos dos fármacos , Transtorno do Deficit de Atenção com Hiperatividade/tratamento farmacológico , Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Hostilidade , Propilaminas/uso terapêutico , Adolescente , Idoso , Cloridrato de Atomoxetina , Criança , Bases de Dados como Assunto/estatística & dados numéricos , Método Duplo-Cego , Feminino , Humanos , Masculino , Metilfenidato/uso terapêutico , Pessoa de Meia-Idade , Razão de Chances , Modelos de Riscos Proporcionais
16.
Toxicon ; 129: 144-152, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28209478

RESUMO

Harmful algal blooms caused by cyanobacteria can present a risk to the safety of drinking- and recreational waters and beachfronts through the production of toxins, particularly microcystin, which are highly resilient to degradation. These blooms are difficult to predict, vary in appearance and toxicity, and can show significant spatial heterogeneity: wind- and current-borne scums can produce an order of magnitude range in toxin levels along shorelines. The growing demand for reliable, cost-effective and rapid methods to detect toxins in bloom material and reduce the risk of public exposure cannot be met by most analytical lab turnaround times. Commercial microcystin test kits are now available, but few have been rigorously field-tested or incorporated into monitoring programmes. Working with a local health agency, we evaluated two kits with different operative ranges of detection, applied to samples covering a wide range of water quality, sample matrices, and bloom composition. We compared their performance against lab analyses using Enzyme-Linked Immunosorbent and Protein Phosphatase Inhibition assays. Both kits could resolve samples with high (<10 µg/L microcystin equivalents (MCequiv)) and low/no toxins, but failed to reliably detect toxin levels between 1 and 5 µg/L, at which threshold there were few false negatives (8%) but âˆ¼ one third of the samples (32%) yielded false positives. We conclude that these kits are potentially useful for screening and informed risk management decisions e.g. on beach closures, but should be followed up with more rigorous tests where needed. We describe how, based on these results, the kits have been successfully incorporated into the routine municipal beach monitoring and advisory programme by the Hamilton Public Health Services (Ontario).


Assuntos
Cianobactérias , Monitoramento Ambiental , Proliferação Nociva de Algas , Microcistinas/análise , Gestão de Riscos , Análise Custo-Benefício , Lagos/análise , Lagos/microbiologia , Reprodutibilidade dos Testes
17.
PLoS One ; 12(10): e0183859, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29020009

RESUMO

Blooms of the potentially toxic cyanobacterium Microcystis are increasing worldwide. In the Laurentian Great Lakes they pose major socioeconomic, ecological, and human health threats, particularly in western Lake Erie. However, the interpretation of "omics" data is constrained by the highly variable genome of Microcystis and the small number of reference genome sequences from strains isolated from the Great Lakes. To address this, we sequenced two Microcystis isolates from Lake Erie (Microcystis aeruginosa LE3 and M. wesenbergii LE013-01) and one from upstream Lake St. Clair (M. cf aeruginosa LSC13-02), and compared these data to the genomes of seventeen Microcystis spp. from across the globe as well as one metagenome and seven metatranscriptomes from a 2014 Lake Erie Microcystis bloom. For the publically available strains analyzed, the core genome is ~1900 genes, representing ~11% of total genes in the pan-genome and ~45% of each strain's genome. The flexible genome content was related to Microcystis subclades defined by phylogenetic analysis of both housekeeping genes and total core genes. To our knowledge this is the first evidence that the flexible genome is linked to the core genome of the Microcystis species complex. The majority of strain-specific genes were present and expressed in bloom communities in Lake Erie. Roughly 8% of these genes from the lower Great Lakes are involved in genome plasticity (rapid gain, loss, or rearrangement of genes) and resistance to foreign genetic elements (such as CRISPR-Cas systems). Intriguingly, strain-specific genes from Microcystis cultured from around the world were also present and expressed in the Lake Erie blooms, suggesting that the Microcystis pangenome is truly global. The presence and expression of flexible genes, including strain-specific genes, suggests that strain-level genomic diversity may be important in maintaining Microcystis abundance during bloom events.


Assuntos
Eutrofização , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Microcystis/genética , Sequência de Bases , Sistemas CRISPR-Cas/genética , Great Lakes Region , Metagenoma , Microcystis/isolamento & purificação , Filogenia , Especificidade da Espécie
18.
Water Res ; 40(9): 1741-53, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16600325

RESUMO

Actinomycetes are a complex group of bacteria present in a wide variety of environments, either as dormant spores or actively growing. Some actinomycetes produce two potent terpenoids (geosmin and 2-methylisoborneol (MIB)) and pyrazines, common causes of drinking water off flavours, and have been implicated in taste and odour episodes. However, isolation from a water source is not evidence that actinomycetes caused a taste and odour event. Dormant spores of actinomycetes may be isolated from aquatic environments in high concentrations, despite production in the terrestrial environment. Similarly, odourous compounds produced by actinomycetes may be produced terrestrially and washed into aquatic environments, with or without the actinomycetes that produced them. Actinomycetes may exist as actively growing mycelium in small, specialized habitats within an aquatic system, but their odourous compounds may influence a wider area. This paper attempts to elucidate the types and activities of actinomycetes that may be found in, or interact with, drinking water supplies.


Assuntos
Actinobacteria/metabolismo , Água Doce/microbiologia , Odorantes , Paladar , Abastecimento de Água , Actinobacteria/isolamento & purificação , Canfanos/análise , Contagem de Colônia Microbiana , Naftóis/análise
19.
Am J Pharm Educ ; 80(2): 21, 2016 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-27073274

RESUMO

Objective. To evaluate the impact of a simulation on pharmacy student attitudes toward poverty using the Attitude toward Poverty (ATP) Short Form scale. Methods. Second-year pharmacy students participated in the 3-hour Missouri Association for Community Action Poverty Simulation. Students completed a survey of the ATP Short Form scale prior to and following participation in the simulation. Results. Significant improvements in attitude were noted in 15 of 21 ATP Short Form items. Improvements in the stigma and structural domains were significant while improvement in the personal deficiency domain was not significant. Conclusions. This poverty simulation exercise positively altered pharmacy student attitudes toward poverty. When combined with didactic and experiential curriculum, this simulation may enhance student achievement of the 2013 Center for the Advancement of Pharmacy Education (CAPE) outcome subdomain of cultural sensitivity.


Assuntos
Atitude do Pessoal de Saúde , Educação em Farmácia/métodos , Simulação de Paciente , Estudantes de Farmácia/psicologia , Currículo , Feminino , Humanos , Masculino , Missouri , Pobreza
20.
Harmful Algae ; 54: 112-127, 2016 04.
Artigo em Inglês | MEDLINE | ID: mdl-28073471

RESUMO

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.


Assuntos
Cianobactérias/genética , Cianobactérias/metabolismo , Odorantes , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/metabolismo , Bioquímica , Cianobactérias/química , Humanos , Paladar
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