Comparative psychology and the grand challenge of drug discovery in psychiatry and neurodegeneration

Drug discovery for brain disorders is undergoing a period of upheaval. Faced with an empty drug pipeline and numerous failures of potential new drugs in clinical trials, many large pharmaceutical companies have been shrinking or even closing down their research divisions that focus on central nervous system (CNS) disorders. In this paper, we argue that many of the difficulties facing CNS drug discovery stem from a lack of robustness in pre-clinical (i.e., non-human animal) testing. There are two main sources for this lack of robustness. First, there is the lack of replicability of many results from the pre-clinical stage, which we argue is driven by a combination of publication bias and inappropriate selection of statistical and experimental designs. Second, there is the frequent failure to translate results in non-human animals to parallel results in humans in the clinic. This limitation can only be overcome by developing new behavioral tests for non-human animals that have predictive, construct, and etiological validity. Here, we present these translational difficulties as a “grand challenge” to researchers from comparative cognition, who are well positioned to provide new methods for testing behavior and cognition in non-human animals. These new experimental protocols will need to be both statistically robust and target behavioral and cognitive processes that allow for better connection with human CNS disorders. Our hope is that this downturn in industrial research may represent an opportunity to develop new protocols that will re-kindle the search for more effective and safer drugs for CNS disorders.     

A new species of the genus Megasis Guenée, 1845 from Turkey (Lepidoptera: Pyralidae)

A new species in the family Pyralidae is described: Megasis kocaki sp. n., of which the adult, head and the male genitalia are illustrated. The new species is compared with the closely allied Megasis hyrcanella Ragonot, 1893.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:0136DD7F-0E91-4114-9B3B-A42E6114A985     

Examining Microscopic Organisms under Augmented Reality Microscope: A 5E Learning Model Lesson

As a fundamental strategy for all science curriculum, inquiry is of prime importance. In order to facilitate inquiry during science education in middle school, 5E learning model was applied in this study. Following 5E learning model during a lesson, students can engage in a topic after being served to mitigate cognitive disequilibrium or familiar with daily-life examples such as yoghurt fermentation, oven spring, etc. explore the topic making an observation or testing hypothesis, explain and relate their experiences scientifically, extend or elaborate their knowledge and then being evaluated. This study introduces a sample 5E learning model for middle school students at the ages of 10–12 in science laboratory with an augmented reality microscope MicrosAR to examine microscopic organisms based on inquiry-based learning.     

The investigation of the secondary structure propensities and free-energy landscapes of peptide ligands by replica exchange molecular dynamics simulations

The conformational states of two peptide sequences that bind to staphylococcal enterotoxin B are sampled by replica exchange molecular dynamic (REMD) simulations in explicit water. REMD simulations were treated with 52 replicas in the range of 280–501 K for both peptides. The conformational ensembles of both peptides are dominated by random coil, bend and turn structures with a small amount of helical structures for each temperature. In addition, while an insignificant presence of β-bridge structures were observed for both peptides, the β-sheet structure was observed only for peptide 3. The results obtained from simulations at 300 K are consistent with the experimental results obtained from circular dichroism spectroscopy. From the analysis of REMD results, we also calculated hydrophobic and hydrophilic solvent accessible surface areas for both peptides, and it was observed that the hydrophobic segments of the peptides tend to form bend or turn structures. Moreover, the free-energy landscapes of both peptides were obtained by principal component analysis to understand how the secondary structural properties change according to their complex space. From the free-energy analysis, we have found several minima for both peptides at decreased temperature. For these obvious minima of both peptides, it was observed that the random coil, bend and turn structures are still dominant and the helix, β-bridge or β-sheet structures can appear or disappear with respect to minima. On the other hand, when we compare the results of REMD with conventional MD simulations for these peptides, the configurations of peptide 3 might be trapped in energy minima during the conventional MD simulations. Hence, it can be said that the REMD simulations have provided a sufficiently high sampling efficiency.     

Differential hydrolysis of homocysteine thiolactone by purified human serum (192)Q and (192)R PON1 isoenzymes

Human serum paraoxonase 1 (PON1) is a HDL-associated enzyme that catalyzes the hydrolysis of a variety of aromatic carboxylic acid esters and several organophosphates. Recently it has been suggested that a physiological substrate of serum PON1 is homocysteine thiolactone which is a putative risk factor in atherosclerosis. In this study, human (192)Q and (192)R PON1 isoenzymes were purified from the respective phenotype human serum, using a protocol consisting of ammonium sulfate precipitation and four chromatography steps: gel filtration, ion-exchange, non-specific affinity, and a second ion-exchange. Using paraoxon as substrate, overall purification fold was found as 742 for (192)R PON1 and 590 for (192)Q PON1. The final purified enzymes were shown as single protein bands close to 45kDa on SDS-PAGE and confirmed by Western blot. Substrate kinetics were studied with phenyl acetate, paraoxon and homocysteine thiolactone. Both PON1 isoenzymes showed mixed type inhibition with phenyl acetate. K(m) values of (192)Q and (192)R PON1 for homocysteine thiolactone were 23.5mM and 22.6mM respectively. For (192)R PON1, the V(max) was 2.5-fold and k(cat)/K(m) was 2.6-fold higher than those for (192)Q PON1 when homocysteine thiolactone is used as substrate. The present data suggest that defining (192)Q and (192)R PON1 isoforms could be a good predictor and prognostic marker in the cardiovascular risk assessment.     

Decreased peroxidase activity in transgenic tobacco and its effect on lignification

An antisense gene construct of a peroxidase gene (Shpx6a) from a tropical pasture legume Stylosanthes humilis was transferred into tobacco cells via Agrobacterium tumefaciens to test whether peroxidase activity could be decreased and what effect this would have on lignification. A large number of tobacco cell lines were regenerated on selective media and stable integration of the transgene was confirmed in randomly selected putative transformants. Analyses of the primary transgenic plants and their progeny (T ₁) demonstrated that the total peroxidase activity was significantly decreased (up to 36%) as compared to that measured in untransformed control plants. Importantly, reduction in peroxidase activity is accompanied by decreases (up to 23%) in lignin content in several transgenic lines.     

Selenium and Topiramate Modulates Brain Microsomal Oxidative Stress Values, Ca2+-ATPase Activity, and EEG Records in Pentylentetrazol-Induced Seizures in Rats

It has been suggested that oxidative stress products play an important role in the etiology of epilepsy. We investigated the effects of selenium (Se) administration on topiramate (TPM)- and pentylentetrazol (PTZ)-induced brain toxicity in rats. Forty male Wistar rats were divided into five equal groups. The first and second groups were used as the control and PTZ groups, respectively. TPM, 50 mg, and Se, 0.3 mg, were administered to rats constituting the third and fourth groups, respectively, for 7 days. The combination of 50 mg TPM and Se was given to animals in the fifth group for 7 days. At the end of 7 days all groups except the first received a single dose of PTZ. Brain cortex samples were taken at 3 h of PTZ administration. PTZ resulted in a significant increase in brain cortex and microsomal lipid peroxidation (LP) levels, number of spikes, and epileptiform discharges on the EEG, although brain cortex vitamin E, brain cortex and microsomal reduced glutathione (GSH), and microsomal calcium (Ca) levels, Ca(2+)-ATPase activities, and latency to first spike on the EEG were decreased by PTZ. LP, GSH, vitamin E, and Ca levels and Ca(2+)-ATPase activities were increased by both Se and TPM, although vitamin A and C concentrations were increased by Se only. There were no effects of TPM and Se on brain cortex and microsomal glutathione peroxidase, brain cortex nitric oxide, or beta-carotene levels. In conclusion, TPM and selenium caused protective effects on PTZ-induced brain injury by inhibiting free radical production, regulating calcium-dependent processes, and supporting the antioxidant redox system.     

Molecularly imprinted cryogels for human interferon‐alpha purification from human gingival fibroblast culture

Interferons are important proteins for the immune system because of their antiviral, anti‐proliferating and immunomodulatory activities. Therapeutic value of these proteins against certain types of tumors caused interest and investigations aimed to obtain highly purified interferons. Molecular imprinting is an efficient method for purification with high selectivity, specificity and good reproducibility. In this study, we utilized advantages of molecular imprinting technique for the purification of interferon from human gingival fibroblast culture. For this purpose, interferon α‐2b imprinted poly(hydroxyethyl methacrylate) cryogel (hIFN‐α‐MIP) was prepared. Optimum adsorption conditions were determined, and maximum adsorption capacity of hIFN‐α‐MIP cryogel was found as 254.8 × 10⁴ IU/g from aqueous solution. All interferon measurements are expressed as International Unit (IU), which is a unit measurement used to quantify biologically active substances like interferon based on their biological activity or effect. Selectivity experiments were performed using competitive proteins and repeated adsorption–desorption studies showed that the adsorption capacity maintained almost at a constant value after ten cycles. For the purification of interferon from human gingival fibroblast culture, fast protein liquid chromatography was used and the specific activity of the purified interferon α‐2b on HeLa cell line was found between the values 3.45 × 10⁸ IU/mg and 3.75 × 10⁸ IU/mg. The results are promising, and the molecular imprinting technique is effective for the purification of interferon α‐2b. Copyright © 2013 John Wiley & Sons, Ltd.