A theoretical and experimental case study of the hydrogen bonding predilection of S-methylcysteine

S-containing amino acids can lead to two types of local NH···S interactions which bridge backbone NH sites to the side chain to form either intra- or inter-residue H-bonds. The present work reports on the conformational preferences of S-methyl-l-cysteine, Cys(Me), using a variety of investigating tools, ranging from quantum chemistry simulations, gas-phase UV and IR laser spectroscopy, and solution state IR and NMR spectroscopies, on model compounds comprising one or two Cys(Me) residues. We demonstrate that in gas phase and in low polarity solution, the C- and N-capped model compound for one Cys(Me) residue adopts a preferred C5–C6γ conformation which combines an intra-residue N–H···O=C backbone interaction (C5) and an inter-residue N–H···S interaction implicating the side-chain sulfur atom (C6γ). In contrast, the dominant conformation of the C- and N-capped model compound featuring two consecutive Cys(Me) residues is a regular type I β-turn. This structure is incompatible with concomitant C6γ interactions, which are no longer in evidence. Instead, C5γ interactions occur, that are fully consistent with the turn geometry and additionally stabilize the structure. Comparison with the thietane amino acid Attc, which exhibits a rigid cyclic side chain, pinpoints the significance of side chain flexibility for the specific conformational behavior of Cys(Me).

     

A review on digestive TAG-lipases of insects

Digestion in insects is a multi-step process to afford nutritional requirements of biological activities. The process starts with nervous stimuli and continues with biochemical activities of digestive enzymes as well as several pumps to digest and absorb the obtained molecules. Carbohydrases, lipases and proteases are the three main digestive enzymes involved in digestion process. Lipases seem to be very important not only for digestive role but also for esteratic activity so that some experts consider lipases as the Class 3 of general esterases. Digestive lipases divided into different groups based on their biological roles namely triacylglycerol lipases, phospholipases and two types of phosphatases. Briefly, triacylglycerol lipases (TAG-lipases) are the hydrolysing enzymes that affect the outer esteric links of triacylglycerols in ingested food. Phospholipases including PLA2 and PLA1 remove phosphatide fatty acids attached to the Position 2 and Position 1. Finally, Alkaline and acid phosphatases are the enzymes that hydrolyse phosphomonoesters under alkaline or acid conditions, respectively. In this review, presence and physiological role of digestive TAG-lipases are explained and their possible importance will be discussed in insect.     

Modulation of Apoptosis and Oxidative Stress with Nesfatin-1 in Doxorubicin Induced Cardiotoxicity in Male Rat

International Journal of Peptide Research and Therapeutics - Fibroblast growth factor 21 (FGF21) is a metabolic regulator with a wide range of biological functions. Although previous studies have...     

Structure Learning in Bayesian Sensorimotor Integration

Previous studies have shown that sensorimotor processing can often be described by Bayesian learning, in particular the integration of prior and feedback information depending on its degree of reliability. Here we test the hypothesis that the integration process itself can be tuned to the statistical structure of the environment. We exposed human participants to a reaching task in a three-dimensional virtual reality environment where we could displace the visual feedback of their hand position in a two dimensional plane. When introducing statistical structure between the two dimensions of the displacement, we found that over the course of several days participants adapted their feedback integration process in order to exploit this structure for performance improvement. In control experiments we found that this adaptation process critically depended on performance feedback and could not be induced by verbal instructions. Our results suggest that structural learning is an important meta-learning component of Bayesian sensorimotor integration.     

Genetic structure of Chrysanthemum genotypes from Iran assessed by AFLP markers and phenotypic traits

Chrysanthemum is popular worldwide as cut flower, potted plant and perennial garden plant. This study used amplified fragment length polymorphism and phenotypic traits to assess genetic diversity and population structure in Chrysanthemum. Results for the phenotypic traits of ray floret number, tubular floret number, flower number, pedicel length, leaflet number on pedicel and days to visible flower bud had high level (i.e., >30 %) evaluations for genotypic coefficient of variation and phenotypic coefficient of variation; thus, heritability for various phenotypic traits ranged from 45.30 to 94.55 %. Phenotypic data clustered the genotypes into four separate groups. Twenty-five primer combinations were used for molecular analysis. On average, each primer combination produced 83.96 polymorphic DNA bands, ranging from 33 to 122 bands. Polymorphic percentage (99.3 %), polymorphism information content (0.43) and Shannon’s information index (0.45) evaluated high levels of genetic variation in the tested genotypes. The Neighbor-Joining (NJ) method grouped genotypes into six clusters, which were in part confirmed by principal coordinate analysis. A Bayesian structure analysis identified four clusters, in which 30 individuals were maintained within the admixed clusters. Results from this study provide appropriate information applicable to designing effective breeding programs and other analyses associated with future studies of Chrysanthemum.     

Effects of Increased Salinity on Growth,Development and Survival in Early Life Stages of the Green Toad Bufotes variabilis (Anura: Bufonidae)

This study examined the effects of increased salinity on growth,development and survival of the Green toad,Bufotes variabilis during embryonic,hatching and early larval periods.Eggs from a single cohort of B.variabilis were subjected to acute and chronic toxicity tests for water salinity ranging from 0.20 to 10 g of salt per liter.Results obtained from this study showed that salinity over 3.70 g/l increased embryonic mortality and reduced percentage of hatching and survival rate of larvae.As larvae tolerated salinity 0.20 to 3.70 g/l with highest survival,but salinity of 10 g/l caused mortality of all individuals within 12 h,7.70–8.70(g/l)within 4.5 days,5.70–6.70 g/l within 10 days and 4.70(g/l)were tolerated within 14 days.Salinity less than 0.70 g/l did not affect survival and hatching success of the embryos.After a 3-week experiment,size of larvae exposed to salinities over 0.70 g/l was lower compared to larvae reared at lower salinity levels.Meanwhile increases in salinity more than 3.70 g/l caused extension in the hatching period.Larvae reared at salinity of 3.70 to 4.70 g/l had morphological abnormalities,such as distortion of tail.     

Antioxidant Defense of Betaine Against Oxidative Stress Induced by Ethanol in the Rat Testes

Oxidative stress is one of the factors associated with decline in fertility and betaine has been shown to bear antioxidant and methyl donor properties in our recent studies. Thus, we designed the present study to examine antioxidant and methyl donor abilities of betaine in oxidative stress induced by ethanol in the rat testes. The adult male Sprague-Dawley rats were divided into four experimental groups and treated daily for 2?months as follows: control, ethanol (4?g/kg, orally), betaine (1.5?% of total diet, orally), and betaine plus ethanol (betaine, 1.5?% of total diet and after 120?min, ethanol 4?g/kg). Sperm motility and concentration significantly increased in betaine group when compared to the ethanol?Ctreated rats. The main antioxidant enzyme (GPx) activity significantly increased (in order compensatory) in ethanol-treated rats when compared to betaine group while, antiperoxidative enzyme (CAT) activity significantly increased in betaine plus ethanol group as compared to ethanol-treated rats. Total homocysteine (tHcy) and TBARS concentration (as a lipid peroxidation marker) also significantly decreased in betaine and betaine plus ethanol groups as compared to ethanol-treated rats. Overall, methyl donor and antioxidant properties of betaine are promising and reduce the elevated tHcy and TBARS concentrations in betaine plus ethanol group. Therefore, betaine might be used as a potential therapy in hyperhomocysteinemia and oxidative stress induced by ethanol in alcoholism.     

The Role of Peptide-Based Tumor Vaccines on Cytokines of Adaptive Immunity: A Review

International Journal of Peptide Research and Therapeutics - Recently, peptide-based materials have been applied to solving many therapeutic problems and have shown particular efficacy as cancer...     

Evaluating the role of autologous mesenchymal stem cell seeded on decellularized pericardium in the treatment of myocardial infarction: an animal study

Inappropriate left ventricular remodeling following myocardial infarction (MI) can result in subsequent severe dysfunction. In this study, we tested the hypothesis that decellularized pericardium (DP) or seeded pericardial patch with autologous adipose-derived mesenchymal stem cells (ADMSCs) could be safely used in a MI scar and could improve heart function. Twelve rabbits were randomly divided into three equal groups. Four weeks after MI induction by ligation of the left anterior descending artery in 12 rabbits, animals of G1 (n = 4) received DP patch with labeled ADMSCs. DP patch was implanted in animals of G2 (n = 4). Rabbits of G3 (n = 4) remained without any intervention after MI induction (control group). Serial examinations including echocardiography, electrocardiography (ECG), scanning electron microscopy, histology and immunohistochemistry (IHC) were performed to evaluate the efficacy of the implanted scaffolds on recovery of the infracted myocardium. The results demonstrated that left ventricular contractile function and myocardial pathological changes were significantly improved in rabbits implanted with either DP or ADMSC-seeded pericardium. However, the seeded pericardium was more effective in scar repairing 2 months after the operation, IHC staining with Desmin and CD34 and positive immunofluorescence staining verified the differentiation of ADMSCs to functional cardiomyocytes. This approach may involve the application of autologous ADMSCs seeded on pericardial patch in an attempt to regenerate a contractible myocardium in an animal model of MI.