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1.
Anal Biochem ; 687: 115429, 2024 04.
Artigo em Inglês | MEDLINE | ID: mdl-38113981

RESUMO

Microcystin-producing cyanobacterial blooms are a global issue threatening drinking water supplies and recreation on lakes and beaches. Direct measurement of microcystins is the only way to ensure waters have concentrations below guideline concentrations; however, analyzing water for microcystins takes several hours to days to obtain data. We tested LightDeck Diagnostics' bead beater cell lysis and two versions of the quantification system designed to give microcystin concentrations within 20 min and compared it to the standard freeze-thaw cycle lysis method and ELISA quantification. The bead beater lyser was only 30 % effective at extracting microcystins compared to freeze-thaw. When considering freeze-thaw samples analyzed in 2021, there was good agreement between ELISA and LightDeck version 2 (n = 152; R2 = 0.868), but the LightDeck slightly underestimated microcystins (slope of 0.862). However, we found poor relationships between LightDeck version 2 and ELISA in 2022 (n = 49, slopes 0.60 to 1.6; R2 < 0.6) and LightDeck version 1 (slope = 1.77 but also a high number of less than quantifiable concentrations). After the quantification issues are resolved, combining the LightDeck system with an already-proven rapid lysis method (such as microwaving) will allow beach managers and water treatment operators to make quicker, well-informed decisions.


Assuntos
Técnicas Biossensoriais , Cianobactérias , Microcistinas/análise , Microcistinas/metabolismo , Proliferação Nociva de Algas , Lagos/análise
2.
Biosensors (Basel) ; 12(8)2022 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-36005037

RESUMO

As cyanobacterial harmful algal bloom (cHAB) events increase in scale, severity, frequency, and duration around the world, rapid and accurate monitoring and characterization tools have become critically essential for regulatory and management decision-making. The composition of cHAB-forming cyanobacteria community can change significantly over time and space and be altered by sample preservation and transportation, making in situ monitoring necessary to obtain real-time and localized information. Sandwich hybridization assay (SHA) utilizes capture oligonucleotide probes for sensitive detection of target-specific nucleic acid sequences. As an amplification-free molecular biology technology, SHA can be adapted for in-situ, real-time or near real-time detection and qualitatively or semi-quantitatively monitoring of cHAB-forming cyanobacteria, owing to its characteristics such as being rapid, portable, inexpensive, and amenable to automation, high sensitivity, specificity and robustness, and multiplexing (i.e., detecting multiple targets simultaneously). Despite its successful application in the monitoring of marine and freshwater phytoplankton, there is still room for improvement. The ability to identify a cHAB community rapidly would decrease delays in cyanotoxin analyses, reduce costs, and increase sample throughput, allowing for timely actions to improve environmental and human health and the understanding of short- and long-term bloom dynamics. Real-time detection and quantitation of HAB-forming cyanobacteria is essential for improving environmental and public health and reducing associated costs. We review and propose to apply SHA for in situ cHABs monitoring.


Assuntos
Cianobactérias , Cianobactérias/genética , Monitoramento Ambiental , Água Doce/microbiologia , Proliferação Nociva de Algas , Humanos , Hibridização de Ácido Nucleico , Fitoplâncton
3.
Environ Sci Technol ; 52(20): 11691-11698, 2018 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-30208702

RESUMO

Harmful algal blooms in freshwater systems are increasingly common and present threats to drinking water systems, recreational waters, and ecosystems. A highly innovative simple to use, portable biosensor system (MBio) for the rapid and simultaneous detection of multiple cyanobacterial toxins in freshwater is demonstrated. The system utilizes a novel planar waveguide optical sensor that delivers quantitative fluorescent competitive immunoassay results in a disposable cartridge. Data are presented for the world's first duplex microcystin (MC)/cylindrospermopsin (CYN) assay cartridge using a combination of fluorophore-conjugated monoclonal antibodies as detector molecules. The on-cartridge detection limits of 20% inhibitory concentration (IC20) was 0.4 µg/L for MC and 0.7 µg/L for CYN. MC assay coverage of eight important MC congeners was demonstrated. Validation using 45 natural lake water samples from Colorado and Lake Erie showed quantitative correlation with commercially available laboratory-based enzyme linked immunosorbent assays. A novel cell lysis module was demonstrated using cyanobacteria cultures. Results show equivalent or better performance than the gold-standard but more tedious 3× freeze-thaw method, with >90% cell lysis for laboratory cultures. The MBio system holds promise as a versatile tool for multiplexed field-based cyanotoxin detection, with future analyte expansion including saxitoxin, anatoxin-a, and marine biotoxins.


Assuntos
Técnicas Biossensoriais , Microcistinas , Colorado , Ecossistema , Água Doce , Proliferação Nociva de Algas
4.
Cytometry B Clin Cytom ; 92(6): 451-455, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-25917935

RESUMO

BACKGROUND: Point-of-care (POC) CD4 T-cell counting is increasingly recognized as providing improved linkage-to-care during management of HIV infection, particularly in resource-limited settings where disease burden is highest. This study evaluated prototype POC CD4 T-cell counters from MBio Diagnostics in the context of low CD4 count, hospitalized patients in Mozambique. This study measured system performance when presented with challenging, low count samples from HIV/AIDS patients with acute illnesses resulting in hospitalization. METHODS: Forty whole blood samples were collected from donors on the medical service at Maputo Central Hospital and absolute CD4 counts were generated on the MBio CD4 system and a reference laboratory using flow cytometry. RESULTS: The mean and median CD4 counts by the flow cytometry reference were 173 and 80 cells/µL, respectively. Correlation between the MBio CD4 System and the reference was good. Bland-Altman analysis showed a mean bias of +15 cells/µL (+9 to +21 cells/µL, 95% CI), and limits of agreement of -47 to 77 cells/µL. For samples with counts >100 cells/µL (N = 14), the mean coefficient of variation was 7.3%. For samples with counts <50 cells/µL, mean absolute bias of replicate samples was 4.8 cells/µL. When two MBio readers were compared, Bland-Altman bias was -4 cells/µL (-13 to +6 cells/µL, 95% CI), and limits of agreement of -63 and +55 cells/µL. CONCLUSIONS: The MBio System holds promise as a POC system for quantitation of CD4 T cells in resource-limited settings given system throughput (80-100 cartridges/day), design simplicity, and ease-of-use. © 2015 International Clinical Cytometry Society.


Assuntos
Contagem de Linfócito CD4/instrumentação , Linfócitos T CD4-Positivos/imunologia , Citometria de Fluxo/instrumentação , Infecções por HIV/diagnóstico , Imunofenotipagem/métodos , Sistemas Automatizados de Assistência Junto ao Leito , Complexo CD3/imunologia , Linfócitos T CD4-Positivos/virologia , Estudos de Casos e Controles , Computadores de Mão/economia , Computadores de Mão/provisão & distribuição , Países em Desenvolvimento , Citometria de Fluxo/economia , Infecções por HIV/imunologia , Infecções por HIV/virologia , Humanos , Imunofenotipagem/instrumentação , Subpopulações de Linfócitos/imunologia , Subpopulações de Linfócitos/virologia , Aplicativos Móveis/economia , Aplicativos Móveis/provisão & distribuição , Moçambique , Padrões de Referência , Reprodutibilidade dos Testes
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