Mice with deletion of the mitochondrial glycerol-3-phosphate dehydrogenase gene exhibit a thrifty phenotype: effect of gender

To define the role of mitochondrial glycerol-3-phosphate dehydrogenase (mGPD; EC 1.1.99.5) in energy balance and intermediary metabolism, we studied transgenic mice not expressing mGPD (mGPD-/-). These mice had approximately 14% lower blood glucose; approximately 50% higher serum glycerol; approximately 80% higher serum triglycerides; and at thermoneutrality, their energy expenditure (Qo(2)) was 15% lower than in wild-type (WT) mice. Glycerol-3-phosphate levels and lactate-to-pyruvate ratios were threefold elevated in muscle, but not in liver, of mGPD-/- mice. WT and mGPD-/- mice were then challenged with a high-fat diet, fasting, or food restriction. The high-fat diet caused more weight gain and adiposity in mGPD-/- than in WT female mice, without the genotype differentially affecting Qo(2) or energy intake. After a 30-h fast, WT female lost 60% more weight than mGPD-/- mice but these latter became more hypothermic. When energy intake was restricted to 50-70% of the ad libitum intake for 10 days, mGPD-/- female mice lost less weight than WT controls, but they had lower Qo(2) and body temperature. WT and mGPD-/- male mice did not differ significantly in their responses to these challenges. These results show that the lack of mGPD causes significant alterations of intermediary metabolism, which are more pronounced in muscle than liver and lead to a thrifty phenotype that is more marked in females than males. Lower T(4)-to-T(3) conversion in mGPD-/- females and a greater reliance of normal females on mGPD to respond to high-fat diets make the lack of the enzyme more consequential in the female gender.     

Comparative studies of wild type Escherichia coli 5-enolpyruvylshikimate 3-phosphate synthase with three glyphosate-insensitive mutated forms: activity, stability and structural characterization

5-Enolpyruvylshikimate 3-phosphate (EPSP) synthase is an essential enzyme of the shikimate pathway and is the target for the herbicide, glyphosate. Several glyphosate-insensitive forms of Escherichia coli EPSP synthase had been reported in the literatures. In the present study the function and structure of wild type enzyme and three different mutated variants (G96A, A183T and G96A/A183T) were compared. Results showed that G96A and G96A/A183T variants are insensitive to glyphosate but display a 31- and 8-fold lower affinity for phosphoenolpyruvate (PEP) as substrate, respectively. In addition, chemical stability of the enzyme variants against Gdn-HCl revealed more stability of the wild type and G96A variant when compared to the G96A/A183T and A183T variants. Comparison of the enzymes containing Ala183Thr replacement with the wild type showed a lower resistance to digestion by the proteases. Moreover, with respect to fluorescence quenching by acrylamide, A183T and G96A/A183T variants were characterized by a higher structural flexibility and more exposure of tryptophan residues to the solvent. In addition, based on the results of circular dichroism and intrinsic fluorescence studies, these two variants represent a significant decrease of secondary structures and changes in the tertiary structure as compared to the wild type and the G96A variant.     

Impregnation of the Bacterial Cellulose Membrane with Biologically Produced Silver Nanoparticles

Different wound dressings with antibacterial property have been surveyed and one among them is bacterial cellulose (BC). Since the BC does not have antibacterial property, the biologically produced silver nanoparticles (SNPs) were impregnated into the BC. For the BC production, Hestrin–Schramm broth was used. Formation of the BC was proven by enzymatic hydrolysis. For SNPs production, the bacterial supernatant was treated with AgNO₃ and formation of SNPs was monitored through spectrophotometer, TEM and XRD. For impregnation of SNPs into the BC, the cleaned membrane was placed in the bacterial supernatant that contained 1 mmol of AgNO₃. The antibacterial assay was done for the BC/SNPs. Enzymatic hydrolysis proved the presence of the BC. Spectrophotometer and XRD results showed the formation of SNPs. TEM analysis revealed the presence of SNPs with sizes around 5–100 nm. SEM micrographs showed the impregnation of SNPs into the BC. Antibacterial test exhibited the antibacterial activity of the BC/SNPs.     

In Silico Design of Multimeric HN-F Antigen as a Highly Immunogenic Peptide Vaccine Against Newcastle Disease Virus

Application of molecular biology techniques to the production of new vaccines against different strains of the Newcastle disease virus (NDV) has been the subject of recent research reports. Development of improved techniques for genome sequencing has led to the recognition of protective mechanisms and the identification of possible candidate antigens. Such procedures could generate meaningful results regarding the virulence determinants of NDV. This study proposed an in silico approach by assembling potential and conserved epitopic regions of hemagglutinin–neuraminidase (HN) and fusion (F) glycoproteins of NDV to induce multiepitopic responses against the virus. Epitope predictions showed that the hypothetical synthetic construct could induce immature B and T cell epitopes that expect a high immune response because of their location in four distinct parts of the construct, namely the head, stalk and the heptad repeated regions known as the HRA and HRB domains. Most regions of the chimeric construct were found to have high antigenic propensity and surface accessibility, which further confirmed the strategy for selection of precise continuous and discontinuous epitopes of HN and F antigens. Thermodynamic folding of mRNA structures revealed correct folding of the RNA construct, indicating good stability of the mRNA to increase the efficiency of translation in the target host. The three-dimensional structure of the native HN-F chimeric protein was successfully generated and validated as a proper model which may define reliability, structural quality and conformation.     

In Search for the Genetic Basis of Quality of Life in Healthy Swedish Women—A GWAS Study Using the iCOGS Custom Genotyping Array

Background

Quality of life (QoL) is increasingly measured in both research and clinical practice. QoL-assessments are built on a long, empirically-based, and stringent approach. There is ample evidence that QoL is, in part, heritable. We therefore performed a GWAS relating genetic variation to QoL in healthy females.

Methods

In 5,142 healthy females, background characteristics (e.g. demographic, clinical, lifestyle and psychological factors) and QoL by means of the EORTC QLQ-C30 were measured. Moreover, women were genotyped using a custom array including ~210,000 single nucleotide polymorphisms (SNPs). Initially, SNPs were related to each QoL-domain, by means of partially adjusted (controlling for age and population stratification) and fully adjusted (controlling for age, population stratification, and background characteristics) regression analyses. Additionally, gene-based analyses were performed relating the combined effect of SNPs within each gene to QoL using the statistical software package VEGAS.

Results

None of the associations between QoL and genetic variation (i.e. individual SNPs and genes) reached the bonferroni corrected significance level.

Conclusion

Reasons for a lack of association between genetic markers and QoL could be low variation in QoL-scores; selecting genetic markers not tagging QoL; or that the genetic effect that impacts one’s QoL is mediated through biological pathways rather than the effect of single SNPs or genes. Therefore, we opt for a pathway-based or system biology approach as a complementary and powerful approach to analyze the combined effect of genes and their biological implications in future studies focusing on QoL-issues.     

In silico experiment with an-antigen-toll like receptor-5 agonist fusion construct for immunogenic application to Helicobacter pylori

BACKGROUNDS:

Helicobacter pylori colonize the gastric mucosa of half of the world''s population. Although it is classified as a definitive type I carcinogen by World Health Organization, there is no effective vaccine against this bacterium. H. pylori evade the host immune response by avoiding toll-like detection, such as detection via toll-like receptor-5 (TLR-5). Thus, a chimeric construct consisting of selected epitopes from virulence factors that is incorporated into a TLR-5 ligand (Pseudomonas flagellin) could result in more potent innate and adaptive immune responses.

MATERIALS AND METHODS:

Based on the histocompatibility antigens of BALB/c mice, in silico techniques were used to select several fragments from H. pylori virulence factors with a high density of B- and T-cell epitopes.

RESULTS:

These segments consist of cytotoxin-associated geneA (residue 162-283), neutrophil activating protein (residue 30-135) and outer inflammatory protein A (residue 155-268). The secondary and tertiary structure of the chimeric constructs and other bioinformatics analyses such as stability, solubility, and antigenicity were performed. The chimeric construct containing antigenic segments of H. pylori proteins was fused with the D3 domain of Pseudomonas flagellin. This recombinant chimeric gene was optimized for expression in Escherichia coli. The in silico results showed that the conserved C- and N-terminal domains of flagellin and the antigenicity of selected fragments were retained.

DISCUSSION:

In silico analysis showed that Pseudomonas flagellin is a suitable platform for incorporation of an antigenic construct from H. pylori. This strategy may be an effective tool for the control of H. pylori and other persistent infections.     

Morphology and fine structure of Acipenser persicus (Acipenseridae, Chondrostei) spermatozoon: Inter-species comparison in Acipenseriformes

This study describes morphology and fine structure of the Persian sturgeon (Acipenser persicus) (Acipenseridae, Chondrostei) spermatozoon. The results show that the spermatozoon of A. persicus is differentiated into an elongated head (length: mean±SD: 7.1±0.5μm) with an acrosome (length: 1.2±0.2μm), a cylindrical midpiece (length: 1.8±0.5μm), a flagellum (length: 50.3±5.9μm) and a total length of 59.2±6.2μm. Ten posterolateral projections (PLPs) arise from the posterior edge of the acrosome and there were 3 endonuclear canals that traversed the nucleus from the acrosomal end to the basal nuclear fossa region. Three to six mitochondria were in peripheral midpiece and the proximal and distal centrioles were located near to "implantation fossa" and basement of the flagellum. The axoneme has a typical eukaryotic structure composed of 9 peripheral microtubules and a central pair of single microtubule surrounded by the plasma membrane. Lateral fins were observed along the flagellum. The fins started and ended at 0.5-1μm from midpiece and at 4-6μm from the end of flagellum. There were significant differences in the size of almost all measured morphological parameters between males and flagellar, midpiece and nucleus characters were more isolated parameters that can be considered for detecting inter-individual variations. This study showed that sperm morphology and fine structure are similar among sturgeon species, but the dimensions of the parameters may differ.