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Abstract: Microcystis aeruginosa accumulation in freshwater poses a significant threat to aquatic organisms and human health. The toxicity of Cyanobacteria metabolites urges for the development of methods for their rapid and efficient detection but what is still almost completely missing is the availability of reagents for the quantification of M. aeruginosa cells in water to monitor the fluctuations of its population. In this study, nanobodies against cell surface antigens of the toxic Cyanobacteria M. aeruginosa were recovered bywhole-cell panning of a naive phage display library. Six unique sequences were identified and three of them sub-cloned and purified as fusion immunoreagents together with either green fluorescent protein or Avi-Tag to be used for diagnostics. Theirspecificity and sensitivity were evaluated by immunofluorescence, by fluorescent and colorimetric cell ELISA and by thermal lens spectrometry (TLS). No cross-reactivity with unrelated microalgae was detected, and both ELISA and TLS methods provided a linear range of detection of several logs. The limit-of-detection of TLS was as low as 1 cell/ml.
Keywords: cyanobacteria, nanobodies, phage display, thermal lens spectrometry, dissertations
Published in RUNG: 10.09.2024; Views: 293; Downloads: 3
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Abstract: Environmental conditions and human activities influence the ubiquity and diversity of microorganisms in the atmosphere thereby acquiring the ability to resist antibiotics which poses serious public threat. Airborne bacteria and fungi isolated using settling plate method from three different points (where kolanuts, meat and onions are sold) at Owena Market, Osun state, Nigeria were assayed for antimicrobial susceptibility using disc diffusion. The microorganisms were identified as Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Proteus vulgaris, Bacillus megaterium, Alcaligenes spp., Aeromonas spp., Escherichia coli, Micrococcus spp., Streptococcus spp., Mortierella polycephala, Epicoccum nigrum, Alternaria spp., Penicillium chrysogenum, Aspergillus flavus, Acremonium spp., Penicillium oxalicum, Cladosporium cladosporiodes, Rhizopus stolonifer, Stemphylium spp., and Trichoderma spp. About 30% of the bacterial isolates were resistant to the antibacterial agents (antibiotics) and all the bacterial isolates were resistant to at least four or more antibiotics while 18% and 64% of the fungi isolated were susceptible to griseofulvin and ketoconazole, respectively. This study shows that the market environment serves as reservoirs for multiple antibiotic resistant bacteria and fungi capable of causing infectious diseases.
Keywords: Airborne microbes, air monitoring, diversity, human activities, multidrug resistance
Published in RUNG: 14.01.2021; Views: 2837; Downloads: 0
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