Analysis of beta-hemolysis in human blood agars by Streptococcus pyogenes

The aim of the study was to assess the reliability of human blood agar media (HuBA) in identifying Streptococcus pyogenes by hemolysis analysis. We analyze several factors that might affect the accuracy of HuBA media for microbial analysis, including incubation time, blood group, Rh factor and presence of antistreptolysin-o.     

The effects of stenosis severity on the hemodynamic parameters-assessment of the correlation between stress phase angle and wall shear stress

To study the effects of increase in the degree of stenosis severity and subsequent complexity of hemodynamic patterns on hemodynamic parameters, experimental investigations and numerical simulations were performed. The correlations between the large negative Stress Phase Angle (SPA), the low mean Wall Shear Stress (WSS) and high Oscillatory Shear Index (OSI) were investigated at the distal shoulder and post-stenotic regions as the outcomes of elevated stenosis severity. Models included non-Newtonian fluid flow in stenotic arteries with 30-80% symmetrical stenoses. To study the interactions between pulsatile WSS and pulsatile wall circumferential stress (WCS) acting on endothelial cells, SPA as the phase difference between WSS and WCS waves was used. Moreover, the distribution of SPA on the lumen axis was compared to the distributions of the mean WSS and OSI that have been regarded until now as the determinants of atherosclerosis-prone regions. Results indicate that an increase in stenosis severity, not only affects the mean WSS, mean WCS and pulse amplitudes, but also influences the phase difference between them. The SPA is large negative on the distal shoulder and post-stenotic areas where atherosclerotic plaque develops. The increasing stenosis severity and the subsequent increasing complexity of hemodynamic patterns affect the correlation between any of the low mean WSS and high OSI with large negative SPA, such that it not only leads to create and develop some regions where the correlation between any of the low mean WSS and high OSI with large negative SPA is well but also leads to create and develop other regions where such correlations fail.     

Delaunay‐based nonlocal interactions are sufficient and accurate in protein fold recognition

This study is aimed at showing that considering only nonlocal interactions (interactions of two atoms with a sequence separation larger than five amino acids) extracted using Delaunay tessellation is sufficient and accurate for protein fold recognition. An atomic knowledge‐based potential was extracted based on a Delaunay tessellation with 167 atom types from a sample of the native structures and the normalized energy was calculated for only nonlocal interactions in each structure. The performance of this method was tested on several decoy sets and compared to a method considering all interactions extracted by Delaunay tessellation and three other popular scoring functions. Features such as the contents of different types of interactions and atoms with the highest number of interactions were also studied. The results suggest that considering only nonlocal interactions in a Delaunay tessellation of protein structure is a discrete structure catching deep properties of the three‐dimensional protein data. Proteins 2014; 82:415–423. © 2013 Wiley Periodicals, Inc.     

A Revision of the Macraster species (Echinodermata,Echinoidea) occurring in the Albian deposits of the Zagros basin,Southwest Iran

The paper describes the spatangoid echinoids belonging to Macraster, which could be found in the Albian deposits (Kazhdumi Formation) at the Anneh anticline situated in Zagros Mountains, Southwest of Iran. The aim is to re-examine, and redefine three species: M. douvillei, M. longesulcatus and M. obtritus. Douvillaster and Macraster genera are synonymized and then the assignment of nominal Tethyan species belonging to the same genera is reviewed. The substantial reduction of species does not strongly impact the biodiversity patterns. Neither the bio-geographical provinciality nor the temporal trends of taxonomic richness are affected. Among the Cretaceous spatangoids, Macraster is a highly specialized taxon that displays outstanding adaptations of the ambulacra to improve in the gaseous exchanges. This, in return, triggers the higher frequency of the taxon in the warm shallow waters of the Tethyan margins, and in oxygen-depleted environments.     

CYP116B5: a new class VII catalytically self‐sufficient cytochrome P450 from Acinetobacter radioresistens that enables growth on alkanes

A gene coding for a class VII cytochrome P450 monooxygenase (CYP116B5) was identified from Acinetobacter radioresistens S13 growing on media with medium (C14, C16) and long (C24, C36) chain alkanes as the sole energy source. Phylogenetic analysis of its N‐ and C‐terminal domains suggests an evolutionary model involving a plasmid‐mediated horizontal gene transfer from the donor Rhodococcus jostii RHA1 to the receiving A. radioresistens S13. This event was followed by fusion and integration of the new gene in A. radioresistens chromosome. Heterologous expression of CYP116B5 in Escherichia coli BL21, together with the A. radioresistens Baeyer–Villiger monooxygenase, allowed the recombinant bacteria to grow on long‐ and medium‐chain alkanes, showing that CYP116B5 is involved in the first step of terminal oxidation of medium‐chain alkanes overlapping AlkB and in the first step of sub‐terminal oxidation of long‐chain alkanes. It was also demonstrated that CYP116B5 is a self‐sufficient cytochrome P450 consisting of a heme domain (aa 1–392) involved in the oxidation step of n‐alkanes degradation, and its reductase domain (aa 444–758) comprising the NADPH‐, FMN‐ and [2Fe2S]‐binding sites. To our knowledge, CYP116B5 is the first member of this class to have its natural substrate and function identified.     

Sleep facilitates long-term face adaptation

Adaptation is an automatic neural mechanism supporting the optimization of visual processing on the basis of previous experiences. While the short-term effects of adaptation on behaviour and physiology have been studied extensively, perceptual long-term changes associated with adaptation are still poorly understood. Here, we show that the integration of adaptation-dependent long-term shifts in neural function is facilitated by sleep. Perceptual shifts induced by adaptation to a distorted image of a famous person were larger in a group of participants who had slept (experiment 1) or merely napped for 90 min (experiment 2) during the interval between adaptation and test compared with controls who stayed awake. Participants'' individual rapid eye movement sleep duration predicted the size of post-sleep behavioural adaptation effects. Our data suggest that sleep prevented decay of adaptation in a way that is qualitatively different from the effects of reduced visual interference known as ‘storage’. In the light of the well-established link between sleep and memory consolidation, our findings link the perceptual mechanisms of sensory adaptation—which are usually not considered to play a relevant role in mnemonic processes—with learning and memory, and at the same time reveal a new function of sleep in cognition.     

First report of a bifunctional chitinase/lysozyme produced by Bacillus pumilus SG2

Bacillus pumilus SG2 isolated from high salinity ecosystem in Iran produces two chitinases (ChiS and ChiL) and secretes them into the medium. In this study, chiS and chiL genes were cloned in pQE-30 expression vector and were expressed in the cytoplasm of Escherichia coli strain M15. The recombinant proteins were purified using Ni-NTA column. The optimum pH and optimum temperature for enzyme activity of ChiS were pH 6, 50°C; those of ChiL were pH 6.5, 40°C. The purified chitinases showed antifungal activity against Fusarium graminearum, Rhizoctonia solani, Magnaporthe grisea, Sclerotinia sclerotiorum, Trichoderma reesei, Botrytis cinerea and Bipolaris sp. Moreover, purified ChiS was identified as chitinase/lysozyme, which are capable of degrading the chitin component of fungal cell walls and the peptidoglycan component of cell walls with many kinds of bacteria (Xanthomonas translucens pv. hordei, Xanthomonas axonopodis pv. citri, Bacillus licheniformis, E. coli C600, E. coli TOP10, Pseudomonas aeruginosa and Pseudomonas putida). Strong homology was found between the three-dimensional structures of ChiS and a chitinase/lysozyme from Bacillus circulans WL-12. This is the first report of a bifunctional chitinase/lysozyme from B. pumilus.