Direct regeneration of Drosera from leaf explants and shoot tips

An efficient protocol for the micropropagation of Drosera anglica, D. binata and D. cuneifolia is described. Proliferation was obtained from leaf segments and shoot tips, which served as initial explants. The regeneration capacity of explants was influenced by factors such as nutrient media, concentrations of growth regulators and the type of medium (liquid or solid). The highest number of plants regenerating from D. binata explants was obtained on the growth regulator-free Vacin and Went medium. In the case of D. anglica the highest proliferation rate was obtained on the Fast medium supplemented with 0.05 M 6-benzyladenine (BA) and 0.005 M -naphthaleneacetic acid (NAA), whereas for D. cuneifolia the optimal regeneration medium proved to be 1/2 MS with the growth regulator supplementation estimated at 0.2 M BA and 0.2 M NAA. Liquid media significantly increased the regeneration potential of D. anglica and D. binata explants.     

Immunocytochemical study of the glucocorticoid receptor in rat liver nuclei after hyperthermic stress

The presence of glucocorticoid receptors (GR) in rat liver nuclei over a 24 h time period following hyperthermic stress at 41 degrees C was immunocytologically studied using unfixed nuclear smears. Liver nuclei in unstressed animals were found to be immunonegative for GR. However, intense GR immunopositivity followed by a subsequent gradual decrease in receptor levels was observed in the nuclei of test animals during the first 2 h after stress. This stress-related increase in the receptor nuclear level was greater than the increase seen after dexamethasone administration. These results suggest that hyperthermic stress could potentiate the hormonal stimulation of receptor nuclear translocation.     

Influence of the length of the phosphate chain in mRNA 5' cap analogues on their interaction with eukaryotic initiation factor 4E

The recognition of the 5'mRNA cap structure m7G(5')ppp(5')N by one of the components of the initiation translation machinery, the eIF4E factor, plays a pivotal role in regulation of the protein synthesis. In the present study we have shown two opposing roles of the cap phosphate chain in the specific eIF4E-cap interaction. The extension of the phosphate chain enhances the binding of the cap to the unphosphorylated eIF4E but destabilises the eIF4E-cap complex in case of the phosphorylated protein.     

Electrostimulation: a future treatment option for patients with neurogenic urodynamic disorders?

This paper provides an overview of electrical stimulation of the nervous system as a treatment option for urodynamic dysfunction and of some of the recent results in this field. The set-up used in our studies for improved bladder filling in spinal cord injured patients by conditional stimulation of the dorsal penile/clitoral nerve is a highly efficient way to limit neurogenic detrusor overactivity and increase bladder capacity. Ongoing studies suggest that recording of bladder nerve activity is stable over time and may be a technique for chronic monitoring of bladder activity. Bladder emptying exploiting an anodal blocking technique permits bladder emptying without simultaneous urethral-perineal contraction, thus enabling a physiological voiding pattern in one continuous sequence. In patients with supraspinal lesions, deep brain electrical stimulation is established only as treatment for a subgroup of patients suffering from Parkinson's disease. Yet, with improved electrode designs and increased clinical experience and experimental results, probably other groups of patients may be candidates for deep brain stimulation. In our study in pigs there was a trend towards increased bladder capacity and compliance in response to stimulation, which is encouraging as several neurological diseases are accompanied by overactive bladder with reduced capacity.     

Simple and efficient synthesis of chiral amino alcohols with an amino acid-based skeleton

Sodium bis(2-methoxyethoxy)aluminum hydride, NaAlH₂(OCH₂CH₂OCH₃)₂, commercially known as Vitride® or Red-Al®, enables rapid synthesis of pure optically active N-protected amino alcohols and peptide alcohols in very high yields. The method is very simple and attractive, as it does not require an additional step of N-protected amino acid derivatization and proceeds without the loss of enantiomeric homogeneity.     

Equilibrium of the Cis-Trans Isomerisation of the Peptide Bond with N-alkyl Amino Acids Measured by 2D NMR

The conformational cis-trans equilibrium around the peptide bond in model tripeptides has been determined by 2D NMR methods (HOHAHA, ROESY). The study was limited to three different N-substituted amino acids in position 2, namely Pro (proline), Tic (1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid), and N-MePhe (N-methylphenylalanine). In all cases the amino acid in position 1 was tyrosine and in position 3, phenylalanine. The results of our studies show that the cis-trans ratio depends mostly on the configuration of the amino acids forming the peptide bond undergoing the cis-trans isomerisation. The amino acid following the sequence (in position 3) does not have much influence on the cis-trans isomerisation, indicating that there is no interaction of the side chains between these amino acids. The model peptides with the L-Tyr-L-AA-(L- or D-)Phe (where AA is N-substituted amino acid) chiralities give 80–100% more of the cis form in comparison to the corresponding peptides with the D-Tyr-L-AA-(L-or D-)Phe chiralities. These results indicate that the incorporation of N-substituted amino acids in small peptides with the same chirality as the precedent amino acid involved in the peptide bond undergoing the cis/trans isomerisation moves the equilibrium to a significant amount of the cis form.     

Anthropometry and Body Composition of Adolescents in Cracow,Poland

Background and Objective

The aim of the present study was to determine the level of adiposity and obesity in Polish adolescents and compare the results with earlier studies conducted in this population as well as those carried out in other populations.

Methods

The study group consisted of 456 boys and 514 girls aged 14-18 years living in Cracow chosen from randomly selected secondary schools. Weight, height, waist, and hip circumference (WC, HC) as well as triceps, biceps, subscapular, and suprailiac skinfold thickness (SFT) were measured. Body mass index (BMI), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), subscapular/triceps skinfold ratio (STR), and percentage body fat were computed. The prevalence of overweight and obesity based on Polish children growth reference were calculated and age-dependent and gender-specific smoothed percentile curves for BMI and ROC curves were generated.

Results

Weight, height, WC, HC (up 16yr), WHtR (up 15yr), and WHR were considerably higher in males than females. Weight, height, and HC increased with age; WHtR remained the same. The prevalence of overweight and obesity were 10.2% (boys 10.3%; girls 10.1%) and 4.2% (boys 5.3%; girls 3.3%). ROC analysis revealed that WHtR was the best tool for detection of obesity (AUC of 0.982±0.007) in males, whereas the sum of four SFTs (AUC: 0.968±0.011) and WHtR (AUC: 0.963±0.012) were the best predictors of obesity in females.

Conclusions

The level of adiposity in Cracow adolescents increased during the last decade. However, it is still lower than in other well-developed societies struggling with obesity epidemics.     

DNA Base Pair Resolution Measurements Using Resonance Energy Transfer Efficiency in Lanthanide Doped Nanoparticles

Lanthanide-doped nanoparticles are of considerable interest for biodetection and bioimaging techniques thanks to their unique chemical and optical properties. As a sensitive luminescence material, they can be used as (bio) probes in Förster Resonance Energy Transfer (FRET) where trivalent lanthanide ions (La³⁺) act as energy donors. In this paper we present an efficient method to transfer ultrasmall (ca. 8 nm) NaYF₄ nanoparticles dispersed in organic solvent to an aqueous solution via oxidation of the oleic acid ligand. Nanoparticles were then functionalized with single strand DNA oligomers (ssDNA) by inducing covalent bonds between surface carboxylic groups and a 5’ amine modified-ssDNA. Hybridization with the 5’ fluorophore (Cy5) modified complementary ssDNA strand demonstrated the specificity of binding and allowed the fine control over the distance between Eu³⁺ ions doped nanoparticle and the fluorophore by varying the number of the dsDNA base pairs. First, our results confirmed nonradiative resonance energy transfer and demonstrate the dependence of its efficiency on the distance between the donor (Eu³⁺) and the acceptor (Cy5) with sensitivity at a nanometre scale.     

Nitrate enhances skeletal muscle fatty acid oxidation via a nitric oxide-cGMP-PPAR-mediated mechanism

Background

Insulin sensitivity in skeletal muscle is associated with metabolic flexibility, including a high capacity to increase fatty acid (FA) oxidation in response to increased lipid supply. Lipid overload, however, can result in incomplete FA oxidation and accumulation of potentially harmful intermediates where mitochondrial tricarboxylic acid cycle capacity cannot keep pace with rates of β-oxidation. Enhancement of muscle FA oxidation in combination with mitochondrial biogenesis is therefore emerging as a strategy to treat metabolic disease. Dietary inorganic nitrate was recently shown to reverse aspects of the metabolic syndrome in rodents by as yet incompletely defined mechanisms.

Results

Herein, we report that nitrate enhances skeletal muscle FA oxidation in rodents in a dose-dependent manner. We show that nitrate induces FA oxidation through a soluble guanylate cyclase (sGC)/cGMP-mediated PPARβ/δ- and PPARα-dependent mechanism. Enhanced PPARβ/δ and PPARα expression and DNA binding induces expression of FA oxidation enzymes, increasing muscle carnitine and lowering tissue malonyl-CoA concentrations, thereby supporting intra-mitochondrial pathways of FA oxidation and enhancing mitochondrial respiration. At higher doses, nitrate induces mitochondrial biogenesis, further increasing FA oxidation and lowering long-chain FA concentrations. Meanwhile, nitrate did not affect mitochondrial FA oxidation in PPARα^?/? mice. In C2C12 myotubes, nitrate increased expression of the PPARα targets Cpt1b, Acadl, Hadh and Ucp3, and enhanced oxidative phosphorylation rates with palmitoyl-carnitine; however, these changes in gene expression and respiration were prevented by inhibition of either sGC or protein kinase G. Elevation of cGMP, via the inhibition of phosphodiesterase 5 by sildenafil, also increased expression of Cpt1b, Acadl and Ucp3, as well as CPT1B protein levels, and further enhanced the effect of nitrate supplementation.

Conclusions

Nitrate may therefore be effective in the treatment of metabolic disease by inducing FA oxidation in muscle.