Total Microcystin Concentration Variability in Water Samples and Recommended Minimum Volume (20 mL) for Freeze Thaw Cycles

Abstract

Cyanobacterial harmful algal blooms (cyanoHABs) continue to be a monitoring and research focus, particularly on the occurrence of toxins like total microcystins. The objectives of this study were to evaluate sampling and analytical variability in measured total microcystin concentrations and then to evaluate the volume of raw water needed in the freeze thaw cycle to reduce sampling variability. Water samples were collected from a recreational lake with annual cyanoHABs, and then 2 mL was used in freeze thaw cycles before total microcystin analysis. Then, sample volumes used in the freeze thaw cycles varied from 2 to 300 mL for total microcystin analysis. With three separate experiments, we observed a great deal of sampling variability (when using 2 mL in the freeze thaw cycles) while analytical variability was much less. In fact, sampling variability could potentially account for temporal variability observed in the routine monitoring. However, when sample volume used in the freeze thaw cycles increased, total microcystin variability decreased. We recommend at least 20 mL to be used in the freeze thaw cycles when analyzing total microcystins in environmental samples.

Evaluation of cyanotoxin L-BMAA effect on α-synuclein and TDP43 proteinopathy

“…Cell abundance was determined in subsamples (5–10 mL) of fixed samples using an inverted microscope (Axiovert 25, Zeiss, Oberkochen, Germany). 1x 10 6 /ml cells were centrifugated and washed with cold PBS 1X than the obtained pellet was homogenized and sonicated in 1 ml of cold water according to ( 50 – 52 ) After 3 cycles of freeze and thaw the supernatant was collected and the protein quantification of crude extract was measured with Thermo Scientific NanoDrop 2000 Spectrophotometer. The optical density of the sample at 730 nm was used to determine cell destruction.…”