Search

The Linum Insertion Sequence 1 (LIS-1) occurs in the genetically plastic flax genotypes in response to the lack or excess of mineral and water nutrition, but also naturally, and can be transmitted to the progeny. We have analyzed 21 ancient Belarusian varieties of flax Linum usitatissimum convar. elongatum Vav. et Ell. The LIS-1 presence or absence was checked for individual plants in at minimum two generations with primer-specific polymerase chain reaction (PCR) and agarose gel electrophoresis. The studied flax varieties formed four groups: non-responsive varieties (LIS-1 was not found, group NR); responsive, which formed and completely lost the insertion (group R0); responsive, which formed and retained LIS-1 (group R1); and responsive unstable (group R2). A statistically significant difference was found in ‘plant height’ (p < 0.05), ‘technical length of the stem’ (p < 0.05) between R0 and NR, and R2 and NR LIS-1 groups. The machine learning algorithm random forest classifier was used to predict the presence, absence or heterozygosity of LIS-1 in flax plants based on their growth and reproductive characteristics. As a result, the accuracy of the prediction was 98% on test data. In terms of sources for the selection of fibre flax varieties adaptive to environmental challenges, the most promising group consists of responsive varieties that have formed LIS-1 insertion (R0, R1 and R2 groups).

In the present study a kinetic-spectrophotometric method for thiocyanate determination is described. The suggested method for the determination of thiocyanate is based on its “Landolt effect” on the reaction of bromate with hydrobromic acid, which leads to the formation of only one halogen bromine. The reaction was monitored spectrophotometrically at the maximum wavelength of astrafloxine FF light absorption at 535 nm. The absorbance of reactants mixture decreased with an increase of the reaction time. The calibration curve for thiocyanate determination was obtained in the concentration range of 0.03–2.0 μg mL−1 under the optimal conditions (pH 1.5; CBrO3- = 7.6 × 10-4 mol L-1; Castrafloxine FF = 1 × 10-5 mol L-1). The limit of detection was 0.01 μg mL−1. The method was successfully applied to the determination of thiocyanate in human saliva samples with satisfactory results.