Synthesis, spectroscopic and X-ray characterization of a copper(II) complex with the Schiff base derived from pyridoxal and aminoguanidine: NMR spectral studies of the ligand

A copper(II) complex with the pyridoxal-aminoguanidine (PL-AG) Schiff base adduct, as an organic compound of the very potent biological activity and promising pharmacological importance in the treatment of diabetic complications, has been prepared and characterized. The X-ray structural analysis of the [CuCl2(PL-AG)] complex showed that it has a distorted pseudo-square-pyramidal (4+1) structure with the tridentate ONN Schiff base in the equatorial plane, with the Cu-O(1), Cu-N(1) and Cu-N(3) bond lengths of 1.917(2)A, 1.930(2)A and 1.984(2)A, respectively. The bond length of the equatorial Cu-Cl(1) is 2.279(1)A, while that of the apical Cu-Cl(2) is 2.792(1)A. Pyridoxal fragment is coordinated in its zwitterionic form. In addition to the X-ray structural analysis, the complex was characterized by IR spectrometric, conductometric and magnetic techniques, and the ligand itself by IR, 1H and 13C NMR spectra.     

Lower Permian Bryozoa from Ellesmere Island (Canada)

A collection of fossils sampled during the 1898–1902 expedition of theFram to the Canadian Arctic Islands includes abundant bryozoans from the Lower Permian (Artinskian) Great Bear Cape Formation of Ellesmere Island. From this material a new genus with one new species —Nansenopora peculiaris n. gen., n. sp. — as well as three new species —Streblotrypella arctica n. sp.,Phragmophera patricki n. sp. andKallodictyon spinatum n. sp. — are described. Furthermore, the speciesUlrichotrypa ramulosa Bassler, 1929 is reported for the first time from the Lower Permian of the Arctic region.     

Biomechanical characterization and clinical implications of artificially induced crouch walking: Differences between pure iliopsoas, pure hamstrings and combination of iliopsoas and hamstrings contractures

The purpose of this study was to characterize biomechanically three different crouch walking patterns, artificially induced in eight neurologically intact subjects and to compare them to selected cases of pathological crouch walking. The subjects were equipped with a lightweight mechanical exoskeleton with artificial muscles that acted in parallel with hamstrings and iliopsoas muscles. They walked at a speed of approximately 1m/s along the walkway under four experimental conditions: normal walking (NW), hamstrings contracture emulation (HAM), iliopsoas contracture emulation (IPS) and emulation of both hamstrings and iliopsoas contractures (IPSHAM). Reflective markers and force platform data were collected and ankle, knee and hip-joint angles, moments and powers were calculated. HAM and IPSHAM shifted ankle-angle rotation profiles into dorsiflexion during midstance compared to IPS and NW where ankle-angle trajectories were similar. HAM, IPS and IPSHAM shifted the knee angle of rotation profiles into flexion during stance, compared to NW. IPS and IPSHAM shifted hip angle of rotation profiles toward pronounced flexion while HAM shifted hip angle of rotation profile toward extension, compared to NW. HAM and IPSHAM significantly increased ankle moment during midstance, compared to IPS and NW where ankle moment profiles were similar. All experimental conditions exhibited similar behavior in the knee-moment profiles during midstance while IPS and IPSHAM knee-moment profiles exhibited significantly higher knee-extension moment during terminal stance and pre-swing. In the hip joint all experimental conditions exhibited similar shape of hip moment profiles throughout the gait cycle. HAM and IPS kinematic and kinetic patterns were qualitatively compared to two selected clinical cases, showing considerable similarity. This implies that distinct differences in kinematics and kinetics between HAM, IPS and IPSHAM may be clinically relevant in helping determine the relative contribution of hamstrings and iliopsoas muscles contractures to particular crouch walking.     

An exodeoxyribonuclease from Streptomyces coelicolor: Expression,purification and biochemical characterization

Streptomyces coelicolor A3(2) produces several intra and extracellular enzymes with deoxyribonuclease activities. The examined N-terminal amino acid sequence of one of extracellular DNAases (TVTSVNVNGLL) and database search on S. coelicolor genome showed a significant homology to the putative secreted exodeoxyribonuclease. The corresponding gene (exoSc) was amplified, cloned, expressed in Escherichia coli, purified to homogeneity and characterized. Exonuclease recExoSc degraded chromosomal, linear dsDNA with 3′-overhang ends, linear ssDNA and did not digest linear dsDNA with blunt ends, supercoiled plasmid ds nor ssDNA. The substrate specificity of recExoSc was in the order of dsDNA > ssDNA > 3′-dAMP. The purified recExoSc was not a metalloprotein and exhibited neither phosphodiesterase nor RNase activity. It acted as 3′-phosphomonoesterase only at 3′-dAMP as a substrate. The optimal temperature for its activity was 57 °C in Tris–HCl buffer at optimal pH = 7.5 for either ssDNA or dsDNA substrates. It required a divalent cation (Mg²⁺, Co²⁺, Ca²⁺) and its activity was strongly inhibited in the presence of Zn²⁺, Hg²⁺, chelating agents or iodoacetate.     

Resveratrol increases vascular oxidative stress resistance

Epidemiological studies suggest that Mediterranean diets rich in resveratrol are associated with reduced risk of coronary artery disease. However, the mechanisms by which resveratrol exerts its vasculoprotective effects are not completely understood. Because oxidative stress and endothelial cell injury play a critical role in vascular aging and atherogenesis, we evaluated whether resveratrol inhibits oxidative stress-induced endothelial apoptosis. We found that oxidized LDL and TNF-alpha elicited significant increases in caspase-3/7 activity in endothelial cells and cultured rat aortas, which were prevented by resveratrol pretreatment (10(-6)-10(-4) mol/l). The protective effect of resveratrol was attenuated by inhibition of glutathione peroxidase and heme oxygenase-1, suggesting a role for antioxidant systems in the antiapoptotic action of resveratrol. Indeed, resveratrol treatment protected cultured aortic segments and/or endothelial cells against increases in intracellular H(2)O(2) levels and H(2)O(2)-mediated apoptotic cell death induced by oxidative stressors (exogenous H(2)O(2), paraquat, and UV light). Resveratrol treatment also attenuated UV-induced DNA damage (comet assay). Resveratrol treatment upregulated the expression of glutathione peroxidase, catalase, and heme oxygenase-1 in cultured arteries, whereas it had no significant effect on the expression of SOD isoforms. Resveratrol also effectively scavenged H(2)O(2) in vitro. Thus resveratrol seems to increase vascular oxidative stress resistance by scavenging H(2)O(2) and preventing oxidative stress-induced endothelial cell death. We propose that the antioxidant and antiapoptotic effects of resveratrol, together with its previously described anti-inflammatory actions, are responsible, at least in part, for its cardioprotective effects.     

Host pathogen protein interactions predicted by comparative modeling

Pathogens have evolved numerous strategies to infect their hosts, while hosts have evolved immune responses and other defenses to these foreign challenges. The vast majority of host-pathogen interactions involve protein-protein recognition, yet our current understanding of these interactions is limited. Here, we present and apply a computational whole-genome protocol that generates testable predictions of host-pathogen protein interactions. The protocol first scans the host and pathogen genomes for proteins with similarity to known protein complexes, then assesses these putative interactions, using structure if available, and, finally, filters the remaining interactions using biological context, such as the stage-specific expression of pathogen proteins and tissue expression of host proteins. The technique was applied to 10 pathogens, including species of Mycobacterium, apicomplexa, and kinetoplastida, responsible for "neglected" human diseases. The method was assessed by (1) comparison to a set of known host-pathogen interactions, (2) comparison to gene expression and essentiality data describing host and pathogen genes involved in infection, and (3) analysis of the functional properties of the human proteins predicted to interact with pathogen proteins, demonstrating an enrichment for functionally relevant host-pathogen interactions. We present several specific predictions that warrant experimental follow-up, including interactions from previously characterized mechanisms, such as cytoadhesion and protease inhibition, as well as suspected interactions in hypothesized networks, such as apoptotic pathways. Our computational method provides a means to mine whole-genome data and is complementary to experimental efforts in elucidating networks of host-pathogen protein interactions.     

Age-related changes in microarchitecture and mineralization of cancellous bone in the porcine mandibular condyle

The mandibular condyle is considered a good model for developing cancellous bone because of its rapid growth and high rate of remodeling. The aim of the present study was to analyze the simultaneous changes in microarchitecture and mineralization of cancellous bone during development in a three-dimensional fashion. Eight mandibular condyles of pigs aged 8 weeks prepartum to 108 weeks postpartum were scanned using microCT with an isotropic spatial resolution of 10 microm. The number of trabeculae decreased during development, whereas both the trabecular thickness and the distance between the trabeculae increased. The bone surface to volume ratio decreased during development, possibly limiting the amount of (re)modeling. Both the mean degree of mineralization and intratrabecular differences in mineralization between the surfaces and cores of trabecular elements increased during development. The trabecular surfaces were more highly mineralized in the older condyles compared to the younger ones. Together with the observed decrease in the relative size of trabecular surface, this finding suggests a decrease in (re)modeling activity during development. In accordance with the general growth and development of the pig, it was concluded that most developmental changes in cancellous bone occur until the age of 40 weeks postpartum.     

The potential pitfalls of using 1,1-diphenyl-2-picrylhydrazyl to characterize antioxidants in mixed water solvents

Approaching living systems, aqueous solutions are appropriate to characterize antioxidants, whereas the frequently used standard 1,1-diphenyl-2-picrylhydrazyl (DPPH) is insoluble in water. Therefore, mixed water-ethanol solvents were investigated using the electron paramagnetic resonance (EPR) spectroscopy. Two forms of DPPH were identified: at higher ethanol ratios a quintet spectrum characteristic of solutions, and at lower ratios, a singlet spectrum typical for solid DPPH, were found. Mixed solvents with 0-50% (v/v) water reproduced the same antioxidant equivalent points well and the reaction rate between DPPH and the antioxidant may increase considerably with increasing water ratios, as demonstrated using vitamin E as an antioxidant. But at still higher water ratios (70-90% (v/v)) the antioxidant activities dropped, since a part of the DPPH in the aggregated form does not react sufficiently with the antioxidants. Characteristics of the most common antioxidants were determined in ethanol or its 50% (v/v) aqueous solution.