Intermolecular amination of allylic and benzylic alcohols leads to effective inhibitions of acetylcholinesterase enzyme and carbonic anhydrase I and II isoenzymes

In this study, we aimed to determine the inhibition effects of novel synthesized sulfamates ( 2a–g ), sulfonamides ( 3b–f ), carbonyl sulfonamides ( 3h and i ), and carbonyl sulfamates ( 4h and 4i ), which were tested against two human cytosolic carbonic anhydrase I and II isozymes (hCA I and II) and acetylcholinesterase (AChE) enzyme. For inhibition properties of allylic sulfamates, the half maximal inhibitory concentration (IC₅₀) and inhibition constant (K_i) were calculated for each novel compounds. The allylic sulfamates showed that K_i values are in the range of 187.33–510.31 pM for hCA I, 104.22–290.09 pM against hCA II, and 12.73–103.63 pM against AChE. The results demonstrated that all newly synthesized compounds had shown effective inhibition against hCA I and II isoenzymes and AChE enzyme.     

Contribution to the taxonomy of Turkish Scorzonera (Asteraceae) taxa based on vegetative anatomy

In the present study, the general stem, root and leaf anatomical features of 59 Scorzonera L. s.l. (Asteraceae) taxa collected from Turkey are presented and evaluated by cluster and principal coordinate analysis. Numerical analyses based on 26 anatomical traits showed that arrangement of tracheal elements in the root, presence of cortical bundles, latex canals, secretory cells and aerenchyma in the stem and mesophyll are valuable for grouping Scorzonera taxa. Dendograms inferred from anatomical data were generally congruent with the traditional subgeneric classification of Scorzonera (Scorzonera L., Podospermum DC., Pseudopodospermum (Lipsch. et Krasch.) Lipsch.). However, the present study also show that the examined species may not be identified only based on the internal morphology of root, stem and leaf. In addition, the results support to treat Podospermum as a distinct genus.     

Direct and protective effects of single or combined addition of vincristine and ε-viniferin on human HepG2 cellular oxidative stress markers in vitro

The objective of this study is to examine the direct effects of low doses and high doses of ε-viniferin, a substance known to be an antioxidant, and vincristine sulphate, a chemotherapeutic agent, alone and in combination [ε-viniferin + vincristine] on HepG2 cell strain, as well as evaluate oxidative stress after incubation periods of 3, 6, and 24 h. Direct effect was determined right after the incubation period; however, for protective effect, antioxidant protection response was determined after the treatment for 1 h with 500 μM H₂O₂, which is an oxidative stressor. For this purpose, superoxide dismutase was determined for enzyme activity, and lipid hydroperoxide (LPO) and reduced glutathione concentrations were studied as indicators of oxidative stress. Results show that low [3.63 µM vincristine + 3.75 µM ε-viniferin] and high [11.25 µM vincristine + 15.8 µM ε-viniferin] doses of combination groups showed similar direct antioxidant effect on LPO levels as protective when compared to the H₂O₂ control group (p < 0.05). Superoxide dismutase enzyme showed a direct antioxidant effect in low and high dose combination groups. In addition, when the incubation period was increased to 24 h, a protective effect was observed in both dose groups (p < 0.05). Reduced glutathione activities showed a direct effect in the low dose combination group, and a protective effect in both the low and high doses in the 24 h. These results show that combined usage of drugs in HepG2 cell strain possesses a protective effect against exogenically produced oxidative stress conditions.     

The effect of some environmental parameters on the growth of yeasts originating from sugar containing foods

In this study, 65 yeast strains originating from sugar containing foods were tested for growth under different environmental conditions. In the experiments performed with glucose and NaCl, inhibition effect was observed at reduced a_w levels. Most of the strains were able to grow at both 4 and 37°C. Of the tested pH values, the most adverse effect on growth of the yeasts was observed at pH 2.5. All of the strains were able to grow at both 5 and 20% CO₂ levels. Acetic and propionic acids were found to be the most effective preservatives for inhibition of the strains. All of the yeasts, except aCandida glucosophila strain, failed to grow in the presence of 0.05% (w/v) sodium benzoate.     

Treatment of COVID-19 patients with quercetin: a prospective,single center,randomized, controlled trial

Scientific research continues on new preventive and therapeutic strategies against severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2). So far, there is no proven curative treatment, and a valid alternative therapeutic approach needs to be developed. This study is designed to evaluate the effect of quercetin in COVID-19 treatment. This was a single-centre, prospective randomized controlled cohort study. Routine care versus QCB (quercetin, vitamin C, bromelain) supplementation was compared between 429 patients with at least one chronic disease and moderate-to-severe respiratory symptoms. Demographic features, signs, laboratory results and drug administration data of patients were recorded. The endpoint was that QCB supplementation was continued throughout the follow-up period from study baseline to discharge, intubation, or death. The most common complaints at the time of hospital admission were fatigue (62.4%), cough (61.1%), anorexia (57%), thirst (53.7%), respiratory distress (51%) and chills (48.3%). The decrease in CRP and ferritin levels was higher in the QCB group (all Ps were < 0.05). In the QCB group, the increase in platelet and lymphocyte counts was higher (all Ps were < 0.05). QCB did not reduce the risk of events during follow-up. Adjustments for statistically significant parameters, including the lung stage, use of favipiravir and presence of comorbidity did not change the results. While there was no difference between the groups in terms of event frequency, the QCB group had more advanced pulmonary findings. QCB supplement is shown to have a positive effect on laboratory recovery. While there was no difference between the groups in terms of event frequency, QCB supplement group had more advanced pulmonar findings, and QCB supplement is shown to have a positive effect on laboratory recovery/results. Therefore, we conclude that further studies involving different doses and plasma level measurements are required to reveal the dose/response relationship and bioavailability of QCB for a better understanding of the role of QCB in the treatment of SARS CoV-2.     

Zooplankton community structure along a trophic gradient in a canyon-shaped dam reservoir

The zooplankton community was surveyed along the longitudinalaxis of Rimov Reservoir (Czech Republic) on seven occasionsduring the vegetative season of 1996. The dimictic Rimov Reservoirhas a pronounced trophic gradient along its axis. In nearlyall samples, rotifers were dominant by numbers and formed onaverage 60–95% of the total zooplankton (including copepodnauplii). There was a consistent pattern of increasing relativeabundance of rotifers in the upper regions of the reservoircompared with the downstream parts. Very large rotifer populationscould develop in the upper regions, often associated with floodevents, but also coinciding with reduced abundance of crustaceansassociated with stronger wash-out effects and the advent ofturbid conditions. There was a greater similarity between twoadjacent sites in the proportions of crustacean species thanof rotifer species. This is partially due to the greater speciesdiversity of rotifers than of crustaceans. The timing of theseasonal succession of zooplankton species showed a coherentpattern along the whole longitudinal profile. The site-specificzooplankton patchiness seems to be reduced as there was no sitedependence if average data on zooplankton composition from downstreamlacustrine sites were compared.     

Long-term biomanipulation of Rimov Reservoir (Czech Republic)

The history of fish, zooplankton and phytoplankton in RimovReservoir during its 14 years existence is documented. Afterthe filling of the reservoir in autumn 1978, the biomass ofplanktivorous fish increased from near zero to 650 kg ha-1 bythe fourth year of the reservoirs existence, after which thefish stock continually decreased under various forms ofbiomanipulative pressure, down to a value of about 100 kg ha-1. Thisdevelopment of fish stock was accompanied by changes in zooplanktonsize structure, but a cascading effect down to reduction ofphytoplankton biomass was not pronounced. The changes ofzooplankton body size structure were: increasing or decreasingaverage size of Daphnia galeata (the main cladoceranherbivore species) and changes in relative proportion ofcladoceran species, but none of the main zooplankton species was replacedor disappeared. The variation in phytoplankton biomass wasexplained by variation in phosphorus concentration and not related tozooplankton structure. It was concluded that the criticalbiomass of planktivorous fish below which the effect of loweringphytoplankton biomass could be observed lies below 100 kg ofplanktivorous fish per hectare. An attempt is made to quantifythe relationship between fish stock density and the size structureof zooplankton potentially able to influence top-down effects onphytoplankton.     

Diversity of Daphnia galeata life history traits in a vertically structured environment

We used laboratory experiments to investigate the life historytraits of clonal lineages of Daphnia galeata isolated from twovertically segregated subpopulations in a deep dimictic reservoir:one from the epilimnion and the other from the deep hypolimnion.We collected clones twice for the experiments, first at thebeginning of thermal stratification in May and then towardsthe end of the season in September. The results for May showedlonger postembryonic development (PED), bigger eggs in the firstclutch and slightly higher somatic increments in the hypolimneticclones. In addition, a remarkable tendency to produce ephippiawas recorded in the hypolimnetic clones, but not in the epilimneticclones. In September, the results were reversed—hypolimneticclones had shorter PED, lower somatic increments and a slightlyhigher number of eggs in the first clutch. Our results suggesta differentiation of life history traits in the two D. galeatapopulations inhabiting contrasting microhabitats of a reservoiras a result of (i) different depth preferences of certain clonesin the beginning of thermal stratification in spring and (ii)divergent selection processes due to segregation in differentenvironmental conditions. The ability of Daphnia to live indiverse environments, causing divergent selection processes,enhances the overall phenotypic and genotypic diversity of thewhole reservoir population.     

Noonan syndrome-associated SHP-2/Ptpn11 mutants enhance SIRPalpha and PZR tyrosyl phosphorylation and promote adhesion-mediated ERK activation

Noonan syndrome (NS) is an autosomal dominant disorder that is associated with multiple developmental abnormalities. Activated mutations of the protein-tyrosine phosphatase, SHP-2/PTPN11, have been reported in approximately 50% of NS cases. Despite being activated, NS-associated SHP-2 mutants require plasma membrane proximity to evoke disease-associated signaling. Here we show that NS-associated SHP-2 mutants induce hypertyrosyl phosphorylation of the transmembrane glycoproteins, SIRPalpha (signal-regulatory protein alpha) and PZR (protein zero-related), resulting in their increased association with NS-associated SHP-2 mutants. NS-associated SHP-2 mutants enhanced SIRPalpha and PZR tyrosyl phosphorylation either by impairing SIRPalpha dephosphorylation or by promoting PZR tyrosyl phosphorylation. Importantly, during embryogenesis in a mouse model of NS, SIRPalpha and PZR were hypertyrosyl-phosphorylated and bound increased levels of the NS-associated SHP-2 mutant. SIRPalpha and PZR have been implicated in extracellular matrix-dependent signaling. Mouse embryonic fibroblasts derived from a mouse model of NS displayed enhanced ERK activation in response to fibronectin plating. Knockdown of SIRPalpha and PZR in these cells attenuated the enhanced activation of ERK following fibronectin plating. Thus, SIRPalpha and PZR serve as scaffolds that facilitate plasma membrane recruitment and signaling of NS-associated SHP-2 mutants.