Impact of food concentration on diel vertical migration behaviour of <Emphasis Type="Italic">Daphnia pulex</Emphasis> under fish predation risk

Vertical migration of Daphnia represents the best-studied predator-avoidance behaviour known; yet the mechanisms underlying the choice to migrate require further investigation to understand the role of environmental context. To investigate the optimal habitat choice of Daphnia under fish predation pressure, first, we selected the individuals exhibiting strong migration behaviour. The animals collected from the hypolimnion during the daytime were significantly larger, being more conspicuous, and in turn performed stronger diel vertical migration (DVM) when exposed to fish cue. We called them strong migrants. Second, we provided the strong migrant D. pulex with food at high and intermediate (1 and 0.4 mg C l⁻¹, respectively) levels, which were well above the incipient limiting level and of high quality. They traded the benefits of staying in the warm water layer and moved down to the cold water in response to fish cue indicating fish predation. The availability of food allowed the animals to stay in the cold hypolimnion. However, at the low food level (0.1 mg C l⁻¹), which is an additional constraint on fitness, Daphnia moved away from the cold hypolimnion. Poor food condition resulted in strong migrant Daphnia to cease migration and remain in the upper warmer water layer. Although temperature is known to be a more important cost factor of DVM than food, our results clearly show that this is only true as long as food is available. It becomes clear that food availability is controlling the direction of vertical positioning when daphnids experience a dilemma between optimising temperature and food condition while being exposed to fish cue. Then they overlook the predation risk. Thus, the optimal habitat choice of Daphnia appears to be a function of several variables including temperature, food levels and fish predation. Handling editor: S. I. Dodson     

Blood and urine iodine levels in patients with gastric cancer

In this study, we aimed to investigate whether there is any relationship between gastric cancer and iodine concentrations in blood and urine in the northeast Anatolia region, where iodine deficiency is common. A total of 56 patients, diagnosed as gastric cancer and 25 healthy volunteers were included in the study. The methods used were based on the Sandell-Kolthoff reaction. The urine iodine concentration (UIC) and serum protein-bound iodine (PBI) levels were higher in patients with gastric cancer compared with healthy control subjects. The UIC in stage IV was higher than all other stages and the control group. The UIC was higher in stages III and IV compared with stages I and II. However, serum PBI levels in stage III were higher compared with stages I, and II and also control group. The serum PBI level in stage IV was higher than stage II and the control group. In the patient and control groups, there were no significant differences in serum PBI and UIC with regard to age or sex. Our results suggested that urinary and blood iodine concentration might be a useful marker for following the disease.     

High glucose-induced mitochondrial respiration and reactive oxygen species in mouse cerebral pericytes is reversed by pharmacological inhibition of mitochondrial carbonic anhydrases: Implications for cerebral microvascular disease in diabetes

Hyperglycemia-induced oxidative stress leads to diabetes-associated damage to the microvasculature of the brain. Pericytes in close proximity to endothelial cells in the brain microvessels are vital to the integrity of the blood–brain barrier and are especially susceptible to oxidative stress. According to our recently published results, streptozotocin-diabetic mouse brain exhibits oxidative stress and loose pericytes by twelve weeks of diabetes, and cerebral pericytes cultured in high glucose media suffer intracellular oxidative stress and apoptosis. Oxidative stress in diabetes is hypothesized to be caused by reactive oxygen species (ROS) produced during hyperglycemia-induced enhanced oxidative metabolism of glucose (respiration). To test this hypothesis, we investigated the effect of high glucose on respiration rate and ROS production in mouse cerebral pericytes. Previously, we showed that pharmacological inhibition of mitochondrial carbonic anhydrases protects the brain from oxidative stress and pericyte loss. The high glucose-induced intracellular oxidative stress and apoptosis of pericytes in culture were also reversed by inhibition of mitochondrial carbonic anhydrases. Therefore, we extended our current study to determine the effect of these inhibitors on high glucose-induced increases in pericyte respiration and ROS. We now report that both the respiration and ROS are significantly increased in pericytes challenged with high glucose. Furthermore, inhibition of mitochondrial carbonic anhydrases significantly slowed down both the rate of respiration and ROS production. These data provide new evidence that pharmacological inhibitors of mitochondrial carbonic anhydrases, already in clinical use, may prove beneficial in protecting the brain from oxidative stress caused by ROS produced as a consequence of hyperglycemia-induced enhanced respiration.     

Design of New and Potent Diethyl Thiobarbiturates as Urease Inhibitors: A Computational Approach

Urease is an important enzyme both in agriculture and medicine research. Strategies based on urease inhibition is critically considered as the first line treatment of infections caused by urease producing bacteria. Since, urease possess agro-chemical and medicinal importance, thus, it is necessary to search for the novel compounds capable of inhibiting this enzyme. Several computational methods were employed to design novel and potent urease inhibitors in this work. First docking simulations of known compounds consists of a set of arylidine barbiturates (termed as reference) were performed on the Bacillus pasteurii (BP) urease. Subsequently, two fold strategies were used to design new compounds against urease. Stage 1 comprised of the energy minimization of enzyme-ligand complexes of reference compounds and the accurate prediction of the molecular mechanics generalized born (MMGB) interaction energies. In the second stage, new urease inhibitors were then designed by the substitution of different groups consecutively in the aryl ring of the thiobarbiturates and N, N-diethyl thiobarbiturates of the reference ligands.. The enzyme-ligand complexes with lowest interaction energies or energies close to the calculated interaction energies of the reference molecules, were selected for the consequent chemical manipulation. This was followed by the substitution of different groups on the 2 and 5 positions of the aryl ring. As a result, several new and potent diethyl thiobarbiturates were predicted as urease inhibitors. This approach reflects a logical progression for early stage drug discovery that can be exploited to successfully identify potential drug candidates.     

Synthesis and bioactivity studies on new 4-(3-(4-Substitutedphenyl)-3a,4-dihydro-3H-indeno[1,2-c]pyrazol-2-yl) benzenesulfonamides

A series of new 4-(3-(4-substitutedphenyl)-3a,4-dihydro-3H-indeno[1,2-c]pyrazol-2-yl) benzenesulfonamides (7–12) was synthesized starting from 2-(4-substitutedbenzylidene)-2,3-dihydro-1H-inden-1-one (1–6) and 4-hydrazinobenzenesulfonamide. The substituted benzaldehydes from which the key intermediate was prepared by introducing 2- or 4-substituents such as fluorine, hydroxy, methoxy, or the 3,4,5-trimethoxy moieties. The compounds were tested for their cytotoxicity, tumor-specificity and potential as carbonic anhydrase (CA, EC 4.2.1.1) inhibitors. The 3,4,5-trimethoxy and the 4-hydroxy derivatives showed interesting cytotoxic activities, which may be crucial for further anti-tumor activity studies, whereas some of these sulfonamides strongly inhibited both human (h) cytosolic isoforms hCA I and II.     

Synthesis,carbonic anhydrase I and II inhibition studies of the 1,3,5-trisubstituted-pyrazolines

4-(3-(4-Substituted-phenyl)-5-phenyl-4,5-dihydro-1H-pyrazol-1-yl) benzenesulfonamides (9–16) were successfully synthesized and their chemical structures were confirmed by ¹H NMR, ¹³C NMR, and HRMS spectra. Carbonic anhydrase I and II inhibitory effects of the compounds were investigated. K_i values of the compounds were in the range of 316.7?±?9.6–533.1?±?187.8?nM towards hCA I and 412.5?±?115.4–624.6?±?168.2?nM towards hCA II isoenzymes. While K_i values of the reference compound Acetazolamide were 278.8?±?44.3?nM and 293.4?±?46.4?nM towards hCA I and hCA II izoenzymes, respectively. Compound 14 with bromine and compound 13 with fluorine substituents can be considered as the leader compounds of the series because of the lowest K_i values in series to make further detailed carbonic anhydrase inhibiton studies.     

Plant Life History and Residue Chemistry Influences Emissions of CO2 and N2O From Soil – Perspectives for Genetically Modified Cell Wall Mutants

Vascular plants have lignified tissues that transport water, minerals, and photosynthetic products throughout the plant. They are the dominant primary producers in terrestrial ecosystems and capture significant quantities of atmospheric carbon dioxide (CO₂) through photosynthesis. Some of the fixed CO₂ is respired by the plant directly, with additional CO₂ lost from rhizodeposits metabolized by root-associated soil microorganisms. Microbially-mediated mineralization of organic nitrogen (N) from plant byproducts (rhizodeposits, dead plant residues) followed by nitrification generates another greenhouse gas, nitrous oxide (N₂O). In anaerobic soils, reduction of nitrate by microbial denitrifiers also produces N₂O. The plant-microbial interactions that result in CO₂ and N₂O emissions from soil could be affected by genetic modification. Down-regulation of genes controlling lignin biosynthesis to achieve lower lignin concentration or a lower guaiacyl:syringyl (G:S) ratio in above-ground biomass is anticipated to produce forage crops with greater digestibility, improve short rotation woody crops for the wood-pulping industry and create second generation biofuel crops with low ligno-cellulosic content, but unharvested residues from such crops are expected to decompose quickly, potentially increasing CO₂ and N₂O emissions from soil. The objective of this review are the following: 1) to describe how plants influence CO₂ and N₂O emissions from soil during their life cycle; 2) to explain how plant residue chemistry affects its mineralization, contributing to CO₂ and N₂O emissions from soil; and 3) to show how modification of plant lignin biosynthesis could influence CO₂ and N₂O emissions from soil, based on experimental data from genetically modified cell wall mutants of Arabidopsis thaliana. Conceptual models of plants with modified lignin biosynthesis show how changes in phenology, morphology and biomass production alter the allocation of photosynthetic products and carbon (C) losses through rhizodeposition and respiration during their life cycle, and the chemical composition of plant residues. Feedbacks on the soil environment (mineral N concentration, soil moisture, microbial communities, aggregation) affecting CO₂ and N₂O emissions are described. Down-regulation of the Cinnamoyl CoA Reductase 1 (CCR1) gene is an excellent target for highly digestable forages and biofuel crops, but A. thaliana with this mutation has lower plant biomass and fertility, prolonged vegetative growth and plant residues that are more susceptible to biodegradation, leading to greater CO₂ and N₂O emissions from soil in the short term. The challenge in future crop breeding efforts will be to select tissue-specific genes for lignin biosynthesis that meet commercial demands without compromising soil CO₂ and N₂O emission goals.     

Assessment of genetic markers and glioblastoma stem-like cells in activation of dendritic cells

Glioblastoma (GBM) is the most common and aggressive intraparenchymal primary brain tumor in adults. The principal reasons for the poor outcomes of GBM are the high rates of recurrence and resistance to chemotherapy. The aim of this study was to determine the role of tailored cellular therapy for GBM with a poor prognosis and compare the activity of dendritic cells (DCs) that have encountered GBM cells. Detecting the correlations between methylation and expression of MGMT and PTEN genes and GBM cancer stem cells (CSCs) markers after co-cultures with a mononuclear cell cocktail are also aims for this study. Allogenic umbilical cord blood (UCB)-derived DCs were labeled with the CD11a and CD123 for immature DCs, and CD80 and CD11c for mature DCs. CD34, CD45, and CD56 cells were isolated from allogenic UCB for using in DCs maturation. GBM CSCs were detected with CD133/1 and CD111 antibodies after co-culture studies. DC activation was carried out via GBM cells including CD133 and CD111 cells and a mononuclear cells cocktail including CD34, CD45, and CD56 natural killer cells. Real-time PCR was performed to detect the expression and promoter methylation status of PTEN and MGMT genes. The expression of CSCs markers was found in all GBM cases, and a statistically significant correlation was found among them after co-culture studies. The most pronounced affinity of DCs to GBM cells was observed at dilutions between 1/4 and 1/256 in co-cultures. There was a statistically significant correlation between cellularity and granularity ratios for CD123 and CD11c. PTEN and MGMT gene expression and methylation values were evaluated with respect to CSCs expression and no statistical significance was found. Activation of DCs might associate with CSCs and the mononuclear cells cocktail including CD34, CD45, and CD56 cells which were obtained from allogenic UCB.     

Heavy metal uptake capacity of fresh water algae (Oedogonium westti) from aqueous solution: A mesocosm research

The green macroalgae present in freshwater ecosystems have attracted a great attention of the world scientists for removal of heavy metals from wastewater. In this mesocosm study, the uptake rates of heavy metals such as cadmium (Cd), nickel (Ni), chromium (Cr), and lead (Pb) by Oedogonium westi (O. westti) were measured. The equilibrium adsorption capabilities of O. westti were different for Cd, Ni, Cr, and Pb (0.974, 0.418, 0.620, and 0.261 mgg^–1, respectively) at 18°C and pH 5.0. Furthermore, the removal efficiencies for Cd, Cr, Ni and Pb were observed from 55–95%, 61–93%, 59–89%, and 61–96%, respectively. The highest removal efficiency was observed for Cd and Cr from aqueous solution at acidic pH and low initial metal concentrations. However, the removal efficiencies of Ni and Pb were higher at high pH and high concentrations of metals in aqueous solution. The results summarized that O. westti is a suitable candidate for removal of selected toxic heavy metals from the aqueous solutions.