The Biochemical Composition and Antioxidant Properties of Fucus vesiculosus from the Arctic Region

Fucus vesiculosus is one of the most prominent brown algae in the shallow waters of the seas of the Arctic region (Barents (BS), White (WS), Norwegian (NS), and Irminger (IS)). The aim of this study was to determine the biochemical composition of F. vesiculosus from the Arctic at different reproductive phases, and to evaluate the antioxidant properties of F. vesiculosus extracts. The amounts of monosaccharides, phlorotannins, flavonoids, and ash and the mineral composition significantly varied in the algae. A strong correlation was established between monosaccharide, phlorotannin, and flavonoid accumulation and water salinity (Pearson’s correlation coefficients r = −0.58, 0.83, and 0.44, respectively; p < 0.05). We noted a negative correlation between the antioxidant activity and the amount of the structural monosaccharides of fucoidan (r = −0.64). A positive correlation of phlorotannins and flavonoids with antioxidant power was confirmed for all samples. The ash accumulation was relatively lower in the sterile phase for the algae from the BS and WS. The correlation between the Metal Pollution Index (MPI) and the reproductive phases was medium with high fluctuation. Meanwhile, the MPI strongly correlated with the salinity and sampling site. The gradient of the MPI values across the sea was in the following ranking order: BS < WS < NS < IS. Taken together, and based on our data on the elemental contents of F. vesiculosus, we believe that this alga does not accumulate toxic doses of elements. Therefore, the Arctic F. vesiculosus could be safely used in food and drug development as a source of active biochemical compounds and as a source of dietary elements to cover the daily nutritional requirements of humans.     

Genetic diversity and origin of cultivated potatoes based on plastid microsatellite polymorphism

The origin of cultivated potatoes has remaining questions. In this study, 237 accessions of all cultivated species and 155 accessions of wild species closely related to cultivated potatoes, including their putative ancestors, were analyzed using 15 plastid microsatellites (SSRs) to investigate genetic diversity and their relationships with the wild species. We here used polymorphic plastid SSRs we developed from potato plastid genome sequences as well as already known plastid SSR markers. All 15 loci were polymorphic and identified a total of 127 haplotypes. Dramatic decreases in levels of genetic diversity were revealed in landraces in comparison with wild ancestor species. The plastid SSR results showed a decrease in haplotype number and diversity from Peru to both north and south. Phylogenetic analysis revealed two distinct groups. One of them, group A, contained the majority of accessions of cultivated species of the Solanum tuberosum Andigenum group including all accessions of cultivated diploid and triploid cytotypes of this group (S. chaucha, S. phureja, and S. stenotomum by a former taxonomic system) and most of tetraploid accessions of the S. tuberosum Andigenum group (S. tuberosum subsp. andigenum), and the majority of accessions of wild ancestors from the northern members of the S. brevicaule complex. Another group B comprised most of the wild species accessions and almost exclusively hybrid cultivated species which have introgressed plastid genomes from the other wild gene pools. Lack of clustering of traditional cultivated species (as used above) support a revised group classification of S. tuberosum.     

The Hymenopteran parasitoid complex associated with Coniesta ignefusalis (Hampson) (Lepidoptera: Crambidae) on Pearl millet in Mali

Phytoparasitica - Moths of Coniesta ignefusalis (Hampson) were collected by automatic light traps on millet field near Bamako in 2018. The light trap data shows three periods of moth flight. The...     

Photocatalytic Treatment of Waste Water from Rice Husk Alkaline Hydrolysate

SUMMARY We carried out photocatalytic treatment of a lignin-free solution of rice husk alkaline hydrolysate [pH of 2, chemical oxygen demand (COD) of 12.8 g/L] using photo-Fenton process in the ultraviolet (UV, wavelength of 365 nm) and visible spectrum. Oxidation of lignin was performed at a constant mass ratio of COD:H2O2 as 1:2 and Fe^2+ concentration of 80 mg/L. It was established that for the destruction of alkaline lignin, exposure to visible or UV radiation was necessary. Decolorization efficiency of a lignin-free solution depends on the dilution rate of the solution. The advanced oxidative photo-Fenton process (UV/Н2О2/Fe^2+) made it possible to reduce the color of lignin-free solution at a dilution ratio of 1:5 by 94% of decolorization efficiency, 87% of phenolic compound and 79% of COD. With the help of gas chromatography, the products of lignin destruction were low-toxic and usable.     

Biological activity of carbonic nano-structures—comparison via enzymatic bioassay

Purpose

The aim of the work is to compare the biological activity of carbonic nano-structures of natural and artificial origination, namely, humic substances (HS) and fullerenols.

Materials and methods

The representative of the fullerenol group, С₆₀О_y(OH)_x where у?+?x?=?20–22, was chosen. Enzyme-based luminescent bioassay was applied to evaluate toxicity and antioxidant properties of HS and fullerenol (F); chemiluminescent luminol method was used to study a content of reactive oxygen species (ROS) in the solutions. Toxicity of the bioactive compounds was evaluated using effective concentrations ЕС₅₀; detoxification coefficients D_OxT were applied to study and compare antioxidant activity of the compounds. Antioxidant activity and ranges of active concentrations of the bioactive compounds were determined in model solutions of organic and inorganic oxidizers—1,4-benzoquinone and potassium ferricianide.

Results and discussion

Values of ЕС₅₀ revealed higher toxicity of HS than F (0.005 and 0.108 g L^?1, respectively); detoxifying concentrations of F were found to be lower. Antioxidant ability of HS was demonstrated to be time-dependent; the 50-min preliminary incubation in oxidizer solutions was suggested as optimal for the detoxification procedure. On the contrary, F’ antioxidant effect demonstrated independency on time. Antioxidant effect of HS did not depend on amphiphilic characteristics of the media (values of D_OxT were 1.3 in the solutions of organic and inorganic oxidizers), while this of F was found to depend: it was maximal (D_OxT?=?2.0) in solutions of organic oxidizer, 1,4-benzoquinone.

Conclusions

Both HS and F demonstrated toxicity and low-concentration antioxidant ability; however, quantitative characteristics of their effects were different. The differences were explained with HS polyfunctionality, higher ability to decrease ROS content, non-rigidity, and diffusion restrictions in their solutions. Antioxidant effect of the bioactive compounds was presumably attributed to catalytic redox activity of their π-fragments. The paper demonstrates a high potential of luminescent enzymatic bioassay to study biological activity of nano-structures of natural and artificial origination.