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Found in: osebi
Keywords: DNAzyme, nanobodies, diagnostics, A. minutum
Published: 10.11.2019; Views: 2543; Downloads: 0
Fulltext (1,77 MB)

Found in: osebi
Keywords: bacteria surface display, nanobodies, HER2, A. minutum
Published: 18.11.2019; Views: 2568; Downloads: 88
Fulltext (12,18 KB)

Found in: osebi
Keywords: biosensors, toxic microalgae, nanobodies, impedance
Published: 07.02.2020; Views: 2353; Downloads: 0
Fulltext (1,26 MB)

Abstract: Early detection and monitoring of toxic microalgae remains a challenge that will be necessary to overcome for understanding harmful algal bloom events and their consequent ecological and environmental impacts. Although there are diagnostic techniques based on microscopy, fluorescence in situ hybridization (FISH), DNA microarrays, real-time PCR, sandwich hybridization assays employed for the detection of harmful algal species, such techniques are not suitable for field monitoring and especially for the quantification of Alexandrium minutum due to abundance of cryptic species that cannot be differentiated based on morphology or genomic traits. These approaches are also time-consuming and laborious, hence there is need for alternative simple, rapid and cost-effective methods. In this study, our aim was to develop different nanobody-based capture strategies for the detection of A. minutum. Nanobodies were successfully displayed on the surface of Escherichia coli to facilitate detection of A. minutum. The method is simple and cost effective as no antibody purification step is necessary. As an alternative, A. minutum was quantified by exploiting the peroxidase activity of a G-quadruplex DNAzyme covalently bound to nanobodies and by means of a label free electrochemical immunosensor which exploit nanobodies bound via an irreversible SpyTag-SpyCatcher system as the specific immunocapture element. Such immunosensor was prepared by immobilizing the SpyTagged anti-A. minutum nanobody (SpyTagged C1) by means of a selfassembled monolayer (SAMs) of L- cysteine (L-Cys) displayed onto a gold nanoparticle-modified glassy carbon electrode. Electrochemical Impedance Spectroscopy (EIS) was performed to measure the electrical response of the circuit as the function of A. minutum immunocaptured cells. The results of EIS studies confirmed that the sensing chip detected A. minutum selectively, exhibited a wide dynamic range spanning from 103 to 109 cell L-1 and a limit of detection of 3.1× 103 cell L-1. The immunosensor data can be recorded and then analyzed with a portable potentiostat. Such device can be interfaced with a smart phone, a condition suitable for the rapid A. minutum quantification in situ.
Found in: osebi
Keywords: Alexandrium minutum, nanobodies, bioreagents, immunosensor, toxic microalgae
Published: 17.06.2020; Views: 3059; Downloads: 204
Fulltext (2,95 MB)

Abstract: Background: The establishment of a biofilm by most pathogenic bacteria has been known as one of the resistance mechanisms against antibiotics. A biofilm is a structural component where the bacterial community adheres to the biotic or abiotic surfaces by the help of Extracellular Polymeric Substances (EPS) produced by bacterial cells. The biofilm matrix possesses the ability to resist several adverse environmental factors, including the effect of antibiotics. Therefore, the resistance of bacterial biofilm-forming cells could be increased up to 1000 times than the planktonic cells, hence requiring a significantly high concentration of antibiotics for treatment. Methods: Up to the present, several methodologies employing antibiotics as an anti-biofilm, antivirulence or quorum quenching agent have been developed for biofilm inhibition and eradication of a pre-formed mature biofilm. Results: Among the anti-biofilm strategies being tested, the sub-minimal inhibitory concentration of several antibiotics either alone or in combination has been shown to inhibit biofilm formation and down-regulate the production of virulence factors. The combinatorial strategies include (1) combination of multiple antibiotics, (2) combination of antibiotics with non-antibiotic agents and (3) loading of antibiotics onto a carrier. Conclusion: The present review paper describes the role of several antibiotics as biofilm inhibitors and also the alternative strategies adopted for applications in eradicating and inhibiting the formation of biofilm by pathogenic bacteria.
Found in: osebi
Keywords: Antibiotics, biofilm inhibition, multiple antibiotics, pathogenic bacteria, resistance mechanism, virulence factors
Published: 14.01.2021; Views: 1612; Downloads: 0
Fulltext (2,61 MB)