Role of the HAMP domain region of sensory rhodopsin transducers in signal transduction

Archaea are able to sense light via the complexes of sensory rhodopsins I and II and their corresponding chemoreceptor-like transducers HtrI and HtrII. Though generation of the signal has been studied in detail, the mechanism of its propagation to the cytoplasm remains obscured. The cytoplasmic part of the transducer consists of adaptation and kinase activity modulating regions, connected to transmembrane helices via two HAMP (histidine kinases, adenylyl cyclases, methyl-accepting chemotaxis proteins, phosphatases) domains. The inter-HAMP region of Natronomonas pharaonis HtrII (NpHtrII) was found to be α-helical [Hayashi, K., et al. (2007) Biochemistry 46, 14380-14390]. We studied the inter-HAMP regions of NpHtrII and other phototactic signal transducers by means of molecular dynamics. Their structure is found to be a bistable asymmetric coiled coil, in which the protomers are longitudinally shifted by ~1.3 ?. The free energy penalty for the symmetric structure is estimated to be 1.2-1.5 kcal/mol depending on the molarity of the solvent. Both flanking HAMP domains are mechanistically coupled to the inter-HAMP region and are asymmetric. The longitudinal shift in the inter-HAMP region is coupled with the in-plane displacement of the cytoplasmic part by 8.6 ? relative to the transmembrane part. The established properties suggest that (1) the signal may be transduced through the inter-HAMP domain switching and (2) the inter-HAMP region may allow cytoplasmic parts of the transducers to come sufficiently close to each other to form oligomers.     

The latent structure of soccer in the phases of attack and defense

With the aim of establishing the latent structure of tactical elements in the attack and defense phases of soccer 117 tactical elements of soccer were defined and their importance assessed by means of 30 variables that determine the basic segments of the game of soccer. 93 attack and 24 defense tactical elements were chosen as the entity sample and described by the 15 variables of the attack phase and 15 variables of the defense phase. Ten competent soccer experts determined the characteristics of the aforementioned entities by means of 30 variables. The experts graded from 0 to 5 the impact of every entity (tactical technique) on the individual variables that describe soccer in its phases of either attack and defense. A high level of inter-expert agreement was reached in regard to the properties of attack and defense techniques, as demonstrated by the objectivity coefficients. According to principal component factor analysis and the Kaiser and Guttman rule a total of five significant latent dimensions were obtained: finishing efficiency, ball possession performance, counter-attack efficiency, combined defense performance, and obstruction and redirection of the opposing team's attack build-up. The research partly resolved the issue of the hypothetical structure of tactical techniques in soccer by dividing the game into phases and sub-phases, attack and defense players'positions, and types (styles) of play in the attack and defense. If it is clear which movement structures have the most significant influence on the efficiency on a particular playing position and performance in the sub-phases and styles of play, it would be possible to create such training operators that will facilitate the formation of the most important motor skills in soccer.     

An in silico canine cardiac midmyocardial action potential duration model as a tool for early drug safety assessment

Cell lines expressing ion channels (IC) and the advent of plate-based electrophysiology device have enabled a molecular understanding of the action potential (AP) as a means of early QT assessment. We sought to develop an in silico AP (isAP) model that provides an assessment of the effect of a compound on the myocyte AP duration (APD) using concentration-effect curve data from a panel of five ICs (hNav1.5, hCav1.2, hKv4.3/hKChIP2.2, hKv7.1/hminK, hKv11.1). A test set of 53 compounds was selected to cover a range of selective and mixed IC modulators that were tested for their effects on optically measured APD. A threshold of >10% change in APD at 90% repolarization (APD(90)) was used to signify an effect at the top test concentration. To capture the variations observed in left ventricular midmyocardial myocyte APD data from 19 different dogs, the isAP model was calibrated to produce an ensemble of 19 model variants that could capture the shape and form of the APs and also quantitatively replicate dofetilide- and diltiazem-induced APD(90) changes. Provided with IC panel data only, the isAP model was then used, blinded, to predict APD(90) changes greater than 10%. At a simulated concentration of 30 μM and based on a criterion that six of the variants had to agree, isAP prediction was scored as showing greater than 80% predictivity of compound activity. Thus, early in drug discovery, the isAP model allows integrating separate IC data and is amenable to the throughput required for use as a virtual screen.     

Carrier-free cellular uptake and the gene-silencing activity of the lipophilic siRNAs is strongly affected by the length of the linker between siRNA and lipophilic group

The conjugation of siRNA to molecules, which can be internalized into the cell via natural transport mechanisms, can result in the enhancement of siRNA cellular uptake. Herein, the carrier-free cellular uptake of nuclease-resistant anti-MDR1 siRNA equipped with lipophilic residues (cholesterol, lithocholic acid, oleyl alcohol and litocholic acid oleylamide) attached to the 5'-end of the sense strand via oligomethylene linker of various length was investigated. A convenient combination of H-phosphonate and phosphoramidite methods was developed for the synthesis of 5'-lipophilic conjugates of siRNAs. It was found that lipophilic siRNA are able to effectively penetrate into HEK293, HepG2 and KB-8-5 cancer cells when used in a micromolar concentration range. The efficiency of the uptake is dependent upon the type of lipophilic moiety, the length of the linker between the moiety and the siRNA and cell type. Among all the conjugates tested, the cholesterol-conjugated siRNAs with linkers containing from 6 to 10 carbon atoms demonstrate the optimal uptake and gene silencing properties: the shortening of the linker reduces the efficiency of the cellular uptake of siRNA conjugates, whereas the lengthening of the linker facilitates the uptake but retards the gene silencing effect and decreases the efficiency of the silencing.     

Genome sequences of three Leuconostoc citreum strains, LBAE C10, LBAE C11, and LBAE E16, isolated from wheat sourdoughs

Leuconostoc citreum is a key microorganism in fermented foods of plant origin. Here we report the draft genome sequence for three strains of Leuconostoc citreum, LBAE C10, LBAE C11, and LBAE E16, which have been isolated from traditional French wheat sourdoughs.     

Draft Genome Sequence of Lactobacillus gigeriorum CRBIP 24.85T,Isolated from a Chicken Crop

We report the draft genome of the strain Lactobacillus gigeriorum CRBIP 24.85^T, isolated from a chicken crop. The total length of the 60 scaffolds is about 1.9 Mb, with a GC content of 38% and 2,062 protein-coding sequences (CDS).     

Genome Sequence of Leuconostoc pseudomesenteroides Strain 4882, Isolated from a Dairy Starter Culture

The nonstarter lactic acid bacterium Leuconostoc pseudomesenteroides is a species widely found in the dairy industry and plays a key role in the formation of aromatic compounds. Here, we report the first genome sequence of a dairy strain of Leuconostoc pseudomesenteroides, which is 2 Mb.