Rapid and Sensitive ELISA Screening Assay for Several Paralytic Shellfish Toxins in Human Urine.

Paralytic shellfish poisoning is caused by a group of paralytic shellfish toxins that are produced by dinoflagellates. Toxins in this group include saxitoxin, neosaxitoxin and gonyautoxins. A rapid diagnostic test to identify poisoning by these toxins can be helpful in guiding the appropriate treatment of victims. Additionally, quick receipt of diagnostic results can provide timely proof that shellfish harvesting should be stopped in a given area, thereby preventing additional exposures. We have developed and validated a rapid urinary enzyme-linked immunosorbent assay-based screening test to diagnose exposure to several major paralytic shellfish toxins. The lower limit of detection (LLOD) for multiple paralytic shellfish toxins was characterized as 0.02, 0.10, 0.10, 1.0, 1.0 and 15 ng/mL for saxitoxin, gonyautoxin 2,3, decarbamoyl gonyautoxin 2,3, decarbamoyl saxitoxin, neosaxitoxin and gonyautoxin 1,4, respectively. No interferences were identified in unspiked pooled urine or in specimens collected from unexposed individuals indicating that this method is specific for the paralytic shellfish toxins tested. The accuracy of this test was demonstrated in 10 individual urine specimens with osmolalities ranging from 217 to 1,063 mOsmol/kg and pHs ranging between 5.06 and 7.45. These specimens were spiked with toxins at their LLODs and the presence of toxins at these concentrations was accurately identified in all cases. These results indicate that this diagnostic test can be used to rapidly and accurately screen urine for paralytic shellfish toxins.

A semi-automated method for purification of milligram quantities of proteins on the QIAcube.

A growing number of studies require the purification of multiple proteins simultaneously and the development of simple economical high-throughput purification methods is essential. We have tested the purification of two related proteins in a variety of conditions to benchmark the semi-automated affinity chromatography method for the QIAcube that we have developed. We find that this new QIAcube method can successfully purify milligram quantities of proteins with minimal user involvement and performs as well as methods based on gravity. The method could easily be adapted to other chromatography resins and should prove to be a versatile method for optimizing protein expression or purification conditions for multiple proteins while obtaining sufficient amounts for subsequent biochemical analyses.