Next Article in Journal
A Green Triboelectric Nano-Generator Composite of Degradable Cellulose, Piezoelectric Polymers of PVDF/PA6, and Nanoparticles of BaTiO3
Previous Article in Journal
Sensor-Based Daily Physical Activity: Towards Prediction of the Level of Concern about Falling in Peripheral Neuropathy
Open AccessArticle

A Carbamoylase-Based Bioassay for the Detection of Paralytic Shellfish Poisoning Toxins

1
CESAM and Chemistry Department, University of Aveiro, 3810-193 Aveiro, Portugal
2
IPMA, Portuguese Institute for the Sea and Atmosphere, 1449-006 Lisbon, Portugal
3
CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, 4050-123 Porto, Portugal
*
Author to whom correspondence should be addressed.
Sensors 2020, 20(2), 507; https://doi.org/10.3390/s20020507
Received: 9 December 2019 / Revised: 6 January 2020 / Accepted: 14 January 2020 / Published: 16 January 2020
(This article belongs to the Section Biosensors)
Out of control proliferation of toxic phytoplankton, called harmful algal blooms (HABs), have a significant economic impact on bivalve aquaculture and harvesting in coastal waters. Some phytotoxins, such as paralytic shellfish toxins (PSTs), are of concern due to the life-threatening symptoms they can cause. Development of rapid and low-cost screening tools would be a welcome addition to the laboratory methodologies employed in routine monitoring programs. However, most of the assays and biosensors for the screening of PSTs, are restricted to a single target, saxitoxin (STX), which is the most potent PST. The present study aimed at developing an assay for the detection of N-sulfocarbamoyl PST—GTX5, which is one of the most abundant toxins in bivalves during G. catenatum blooms as found on the Portuguese coast. Enzymatic assay employing PSTs’ transforming enzyme—carbamoylase—was proposed. Carbamoylase was extracted and purified from the surf clam S. solida. Carbamoylase displayed similar specificity to both carbamate (STX) and N-sulfocarbamate toxins (GTX5 and C1+2) converting them into decarbamoyl saxitoxin (dcSTX) and decarbamoyl gonyautoxins 2+3 (dcGTX2+3), respectively. The enzymatic assay involved hydrolysis of GTX5 by carbamoylase and quantification of the product of enzymatic reaction, dcSTX, using a potentiometric chemical sensor. A potentiometric sensor with plasticized PVC membrane that displayed sensitivity to dcSTX and selectivity in the presence of GTX5 was employed. Enzymatic assay allowed determination of GTX5 in the concentration range from 0.43 to 3.30 µmolL−1, which encompasses levels of GTX5 in contaminated bivalve extracts with toxicities above PSTs regulatory limits. The feasibility of the carbamoylase-based potentiometric assay for detection of GTX5 was demonstrated. View Full-Text
Keywords: carbamoylase; paralytic shellfish toxins; potentiometric sensor; gonyautoxin 5; decarbamoylsaxitoxin; enzymatic assay carbamoylase; paralytic shellfish toxins; potentiometric sensor; gonyautoxin 5; decarbamoylsaxitoxin; enzymatic assay
Show Figures

Figure 1

MDPI and ACS Style

Raposo, M.; Botelho, M.J.; Costa, S.T.; Gomes, M.T.S.R.; Rudnitskaya, A. A Carbamoylase-Based Bioassay for the Detection of Paralytic Shellfish Poisoning Toxins. Sensors 2020, 20, 507.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop