Mycosporine-like amino acids : potential health and beauty ingredients

Human skin is constantly exposed to damaging ultraviolet radiation (UVR), which induces a number of acute and chronic disorders. To reduce the risk of UV-induced skin injury, people apply an additional external protection in the form of cosmetic products containing sunscreens. Nowadays, because of the use of some chemical filters raises a lot of controversies, research focuses on exploring novel, fully safe and highly efficient natural UV-absorbing compounds that could be used as active ingredients in sun care products. A promising alternative is the application of multifunctional mycosporine-like amino acids (MAAs), which can effectively compete with commercially available filters. Here, we outline a complete characterization of these compounds and discuss their enormous biotechnological potential with special emphasis on their use as sunscreens, activators of cells proliferation, anti-cancer agents, anti-photoaging molecules, stimulators of skin renewal, and functional ingredients of UV-protective biomaterials

Decomposition products of cylindrospermopsin – a cyanotoxin produced by Raphidiopsis raciborskii (Woloszynska)

Toxins produced by cyanobacteria (cyanotoxins) and released into water have become a serious problem worldwide due to the increasing morbidity and mortality of living organisms they have caused. The ability to synthesize the cytotoxic alkaloid cylindrospermopsin (CYN) has been demonstrated in several freshwater species of cyanobacteria. CYN is highly chemically stable under environmental factors and decomposes only under alkaline conditions, where it forms derivatives. The toxicity potential of the decomposition products formed at pH 10 combined with high temperature (100°C) or UV-B irradiation (36 µmol m−2 s−1) has been research based on the crustacean Thamnocephalus platyurus (Thamnotoxkit FTM) and bacteria Vibrio fischeri (Deltatox® II) bioassays. This paper is a continuation and completion of our previous experiments and the obtained results showed that the applied conditions contributed to the decomposition of the CYN molecule to non-toxic products and its structural modifications by separating the uracil ring or/and the sulfate group from the tricyclic guanidine moiety, leading to a reduction in its toxicity. To the best of our knowledge, this is the first report describing the toxicity of CYN decomposition products formed under alkaline conditions combined with boiling temperature or UV-B irradiation.Toxins produced by cyanobacteria (cyanotoxins) and released into water have become a serious problem worldwide due to the increasing morbidity and mortality of living organisms they have caused. The ability to synthesize the cytotoxic alkaloid cylindrospermopsin (CYN) has been demonstrated in several freshwater species of cyanobacteria. CYN is highly chemically stable under environmental factors and decomposes only under alkaline conditions, where it forms derivatives. The toxicity potential of the decomposition products formed at pH 10 combined with high temperature (100°C) or UV-B irradiation (36 µmol m−2 s−1) has been research based on the crustacean Thamnocephalus platyurus (Thamnotoxkit FTM) and bacteria Vibrio fischeri (Deltatox® II) bioassays. This paper is a continuation and completion of our previous experiments and the obtained results showed that the applied conditions contributed to the decomposition of the CYN molecule to non-toxic products and its structural modifications by separating the uracil ring or/and the sulfate group from the tricyclic guanidine moiety, leading to a reduction in its toxicity. To the best of our knowledge, this is the first report describing the toxicity of CYN decomposition products formed under alkaline conditions combined with boiling temperature or UV-B irradiation

Atrial fibrillation genetic risk differentiates cardioembolic stroke from other stroke subtypes

AbstractObjectiveWe sought to assess whether genetic risk factors for atrial fibrillation can explain cardioembolic stroke risk.MethodsWe evaluated genetic correlations between a prior genetic study of AF and AF in the presence of cardioembolic stroke using genome-wide genotypes from the Stroke Genetics Network (N = 3,190 AF cases, 3,000 cardioembolic stroke cases, and 28,026 referents). We tested whether a previously-validated AF polygenic risk score (PRS) associated with cardioembolic and other stroke subtypes after accounting for AF clinical risk factors.ResultsWe observed strong correlation between previously reported genetic risk for AF, AF in the presence of stroke, and cardioembolic stroke (Pearson’s r=0.77 and 0.76, respectively, across SNPs with p &lt; 4.4 × 10−4 in the prior AF meta-analysis). An AF PRS, adjusted for clinical AF risk factors, was associated with cardioembolic stroke (odds ratio (OR) per standard deviation (sd) = 1.40, p = 1.45×10−48), explaining ∼20% of the heritable component of cardioembolic stroke risk. The AF PRS was also associated with stroke of undetermined cause (OR per sd = 1.07, p = 0.004), but no other primary stroke subtypes (all p &gt; 0.1).ConclusionsGenetic risk for AF is associated with cardioembolic stroke, independent of clinical risk factors. Studies are warranted to determine whether AF genetic risk can serve as a biomarker for strokes caused by AF.</jats:sec

A speaker recognition solution for identification and authentication

M.Com. (Informatics)A certain degree of vulnerability exists in traditional knowledge-based identification and authentication access control, as a result of password interception and social engineering techniques. This vulnerability has warranted the exploration of additional identification and authentication approaches such as physical token-based systems and biometrics. Speaker recognition is one such biometric approach that is currently not widely used due to its inherent technological challenges, as well as a scarcity of comprehensive literature and complete open-source projects. This makes it challenging for anyone who wishes to study, develop and improve upon speaker recognition for identification and authentication. In this dissertation, we condense some of the available speaker recognition literature in a manner that would provide a comprehensive overall picture of speaker identification and authentication to a wider range of interested audiences. A speaker recognition solution in the form of an open, user-friendly software prototype environment is presented, called SRIA (Speaker Recognition Identification Authentication). In SRIA, real users may enrol and perform speaker identification and authentication tasks. SRIA is intended as platform for speaker recognition understanding and further research and development

Effect of Microcystin-LR, Nodularin, Anatoxin-a, β-N-Methylamino-L-Alanine and Domoic Acid on Antioxidant Properties of Glutathione

Cyanobacteria produce a range of toxic secondary metabolites that affect many processes in human, animal and also plant cells. In recent years, some efforts have concentrated on deepening the understanding of their effect on living cells in the context of the disruption of antioxidant systems. Many results suggest that cyanotoxins interfere with glutathione (GSH) metabolism, which often leads to oxidative stress and, in many cases, cell death. Knowledge about the influence of cyanotoxins on enzymes involved in GSH synthesis or during its antioxidant action is relatively broad. However, to date, there is no information about the antioxidant properties of GSH after its direct interaction with cyanotoxins. In this paper, we investigated the effect of four cyanotoxins belonging to the groups of hepatotoxins (microcystin-LR and nodularin) or neurotoxins (anatoxin-a and β-N-methylamino-L-alanine) on the in vitro antioxidant properties of GSH. Moreover, the same study was performed for domoic acid (DA) produced by some diatoms. The obtained results showed that none of the studied compounds had an effect on GSH antioxidant potential. The results presented in this paper are, to the best of our knowledge, the first description of the kinetics of scavenging radicals by GSH reactions under the influence of these cyanotoxins and DA. This work provides new and valuable data that broadens the knowledge of the impact of cyanotoxins and DA on GSH metabolism and complements currently available information. Future studies should focus on the effects of the studied compounds on antioxidant systems in vivo.</jats:p