Neuronal responses to myelin are mediated by rho kinase

CNS myelin inhibits axon growth due to the expression of several growth-inhibitory proteins, including myelin-associated glycoprotein, oligodendrocyte myelin glycoprotein and Nogo. Myelin-associated inhibitory proteins activate rho GTPase in responsive neurons. Rho kinase (ROCK) has been implicated as a critical rho effector in this pathway due to the ability of the pharmacological inhibitor Y-27632 to circumvent myelin-dependent inhibition. Y-27632, however, inhibits the activity of additional kinases. Using three independent approaches, we provide direct evidence that ROCKII is activated in response to the myelin-associated inhibitor Nogo. We demonstrate that Nogo treatment enhances ROCKII translocation to the cellular membrane in PC12 cells and enhances ROCKII kinase activity towards an in vitro substrate. In addition, Nogo treatment enhances phosphorylation of myosin light chain II, a known ROCK substrate. Further, we demonstrate that primary dorsal root ganglia neurons can be rendered insensitive to the inhibitory effects of myelin via infection with dominant negative ROCK. Together these data provide direct evidence for a rho-ROCK-myosin light chain-II signaling cascade in response to myelin-associated inhibitors.     

Evidence that GAD65 mediates increased GABA synthesis during intense neuronal activity in vivo

In this study we tested the hypothesis that the 65-kDa isoform of glutamate decarboxylase (GAD(65)) mediates activity-dependent GABA synthesis as invoked by seizures in anesthetized rats. GABA synthesis was measured following acute GABA-transaminase inhibition by gabaculine using spatially localized (1)H NMR spectroscopy before and after bicuculline-induced seizures. Experiments were conducted with animals pre-treated with vigabatrin 24 h earlier in order to reduce GAD(67) protein and also with non-treated controls. GAD isoform content was quantified by immunoblotting. GABA was higher in vigabatrin-treated rats compared to non-treated controls. In vigabatrin-treated animals, GABA synthesis was 28% lower compared to controls [p < 0.05; vigabatrin-treated, 0.043 +/- 0.011 micromol/(g min); non-treated, 0.060 +/- 0.014 micromol/(g min)] and GAD(67) was 60% lower. No difference between groups was observed for GAD(65). Seizures increased GABA synthesis in both control [174%; control, 0.060 +/- 0.014 micromol/(g min) vs. seizures, 0.105 +/- 0.043 micromol/(g min)] and vigabatrin-treated rats [214%; control, 0.043 +/- 0.011 micromol/(g min); seizures, 0.092 +/- 0.018 micromol/(g min)]. GAD(67) could account for at least half of basal GABA synthesis but only 20% of the two-fold increase observed in vigabatrin-treated rats during seizures. The seizure-induced activation of GAD(65) in control cortex occurs concomitantly with a 2.3-fold increase in inorganic phosphate, known to be a potent activator of apoGAD(65)in vitro. Our results are consistent with a major role for GAD(65) in activity-dependent GABA synthesis.     

Peptides containing 4-amino-1,2-dithiolane-4-carboxylic acid (Adt): conformation of Boc-Adt-Adt-NHMe and NH...S interactions.

To study the conformational preferences induced by the insertion of the 4-amino-1,2-dithiolane-4-carboxylic acid (Adt) residue into a peptide backbone, the achiral N-protected dipeptide methylamide Boc-Adt-Adt-NHMe (1) was synthesized and its crystal state and solution conformation studied and compared with that exhibited by its carba-analogue Boc-Ac5c-Ac5c-NHMe containing two residues of 1-aminocyclopentane-1-carboxylic acid (Ac5c). Compound 1 in the crystal adopts a type-III beta-turn conformation and an analogous structure is that preferred in chloroform solution as established by 1H-NMR and NOE information. In the crystal packing three different Adt rings form a cavity and the involved sulphur atoms give rise to unusual multiple interactions with one NH group. The chemical nature of these intermolecular and intramolecular main-chain...side-chain NH...S interactions are discussed in terms of quantum chemical calculations.     

A shifty stop for a hairy tail

The tail apparatus of the bacteriophage SPP1 is an extraordinary approximately 1600-A-long molecular machine. The tail mediates attachment of the virus to the host surface receptor, as well-as ejection of the viral genome into the host. The distal tip of the tail binds the extracellular ectodomain of the Bacillus subtilis receptor YueB, while the tail tube provides a conduit to funnel the viral genome into the host. This process, which culminates with the ejection of the approximately 44 kb of viral DNA across the thick, cell envelope of the Gram-positive bacterial cell, takes place in a time scale of seconds to minutes and represents a remarkable example of biotransformation. In this issue of Molecular Microbiology, Auzat et al. provide compelling evidence that the two major structural proteins of the SPP1 tail, gp17.1 (approximately 19.1 kDa) and gp17.1* (approximately 28 kDa), share a common N-terminal sequence, and that gp17.1* is generated by a translational frameshift in the gene 17.1. The extra domain fused to gp17.1* is synthesized by a +1 programmed translational frameshift at the end of gene 17.1, which leads to the synthesis of approximately one gp17.1* for every three equivalents of gp17.1. This finding extends our current knowledge of translational frameshifts and provides a framework to understand how Siphoviridae phages like SPP1 have developed long-tail machines using only two major structural proteins.     

Budding yeast with human telomeres: a puzzling structure

Telomeres share some common features among eukaryotes, with few exceptions such as the fruit fly Drosophila that uses transposons as telomeres, they consist of G-rich repetitive DNA that is elongated by telomerase and/or alternative pathways depending on recombination. Telomere structure comprises both cis-acting satellite DNA (telomeric DNA) and proteins that interact directly and/or indirectly with the underlying DNA. Telomeric DNAs are surprisingly conserved among the vertebrates and very similar in most eukaryotes, but present some differences in yeast such as Saccharomyces cerevisiae. The telomeric proteins are more variable although the basic mechanisms which control telomere lengthening and capping are very similar, in fact orthologues of the yeast telomeric proteins, which have been studied first, have been identified in other organisms. Here we describe the structure of human telomeres in budding yeast as compared to canonical yeast and mammalian telomeres taking into consideration the more recent findings highlighting the mechanisms that are responsible for chromosome end protection and lengthening, and the role of chromatin organization in telomere function. This yeast represents a model for the study of mammalian telomeres that could be reconstituted step-by-step in all their components, moreover it could be useful for the assembly of mammalian artificial chromosome.     

An examination of training on the VertiMax resisted jumping device for improvements in lower body power in highly trained college athletes

Training to develop superior muscular power has become a key component to most progressive sport conditioning programs. Conventional resistance training, plyometrics, and speed/agility modalities have all been employed in an effort to realize superlative combinations of training stimuli. New training devices such as the VertiMax resisted jump trainer are marketed as a means of improving lower body reactive power. The purpose of this study was to evaluate the effectiveness of the VertiMax, in combination with traditional training modalities, for improvements in lower body power among highly trained athletes. Forty men and women Division I collegiate athletes representing the sports of baseball, basketball, soccer, gymnastics, and track completed a 12-week mixed-methods training program. Two groups were constructed with both groups performing the same conventional resistance training and strength training exercises. The training control group performed traditional plyometric exercises while the experimental group performed similar loaded jump training on the VertiMax. Lower body power was measured before and after the training program by the TENDO FiTROdyne Powerlizer and statistically compared for differences between groups. Data analyses identified a significant (p < 0.05) and meaningful difference between power development among the 2 groups, with the VertiMax eliciting a greater treatment effect (effect size = 0.54) over conventional resistance and plyometric training alone (effect size = 0.09). These data convincingly demonstrate that the VertiMax represents an effective strategy for developing lower body power among trained college athletes, when combined with traditional strength and conditioning approaches.     

Holocene glaciations in the Ema Glacier valley, Monte Sarmiento Massif, Tierra del Fuego

Investigations carried out in the Ema Glacier valley, Tierra del Fuego, on the eastern side of Monte Sarmiento Massif, enable the recognition of five Holocene glacial events. The oldest glacial advance deposited the so-called external moraines of Ema Glacier, with a probable occurrence between 6000 and 5000 14 C y BP without discarding the potential for these deposits to be from Lateglacial time. The remaining four readvances built up a complex inner moraine system named informally internal moraines of Ema Glacier. The oldest recognized till unit that constitutes this proximal moraine system was deposited shortly before 3135 14 C y BP, when glaciolacustrine sedimentation took place during glacier recession. Subsequent glacial advances accumulated till at about 1288 14 C y, shortly after 695 14 C y, and between 379 14 C y and 60 y BP. This chronology of Holocene glacier events coincides with and is well complemented by the one established by other authors for Fiordo Pía at Cordillera Darwin, 75 km to the east. The Ema-Pía chronology is used to calibrate tentatively a series of moraine belts previously identified in the mountain ranges adjacent to Ushuaia, 150 km SE of the surveyed region. A comparative chart shows that the chronological data obtained for the neoglacial readvances in Tierra del Fuego are in accordance with those for the southern Patagonian Andes further north. It follows that the Holocene behavior of the glaciers in the Andean region of Tierra del Fuego and southern Patagonia is essentially a response to the same regional climate change.     

Comparative environmental assessment of conventional,electric, hybrid,and fuel cell powertrains based on LCA

Purpose

The purpose of this study is to compare the environmental impact differences of four types of vehicles on a life cycle assessment (LCA) perspective: a conventional gasoline vehicle, a pure electric vehicle, a plug-in hybrid gasoline-electric vehicle, and a plug-in hybrid fuel cell-battery vehicle. The novelty of the approach is to consider the different powertrains—electric and hybrids—as a repowering of the conventional powertrain. This way, the attention can be focused only on the powertrain differences and inefficiencies, with the added value of avoiding further assumptions, which could cause the analysis to be somehow rough.

Methods

Thus, we compared four powertrain scenarios maintaining the same vehicle chassis, and we compared the impacts from the powertrain production, vehicle use phase, and powertrain end of life only. Hence, special attention was paid to the inventory for powertrain construction and use phase. For the powertrain components, an accurate literature survey has been carried out for the life cycle inventory. For the use phase, several driving cycles, both standardized and real-world type, have been simulated in order to properly evaluate the effect on the fuel/electricity consumption. For the comparison, environmental indicators according to cumulative energy demand (CED) and ReCiPe Midpoint methods have been used. This way, an analysis of the environmental impact, based on a life cycle impact assessment approach, is provided, which allows thoroughly comparing the systems based on the different powertrains. Moreover, a sensitivity analysis on different energy mixes has been included, which represents also a way to take into account changes in electricity production.

Results and discussion

Results are presented according to life cycle impact assessment, which examines the mass and energy inventory input and output data for a product system to translate these data to better identify their possible environmental relevance and significance. In the case of the climate change (CC), fuel depletion (FD), and CED indicators, the lowest value corresponds to the plug-in hybrid gasoline-electric vehicle, followed by the plug-in hybrid fuel cell-battery vehicle, the pure electric, and finally the conventional gasoline vehicle. Substituting a conventional gasoline powertrain with the corresponding pure electric one offers the lowest reduction, but still of valuable amount. In our analysis, for the considered systems, the reduction of the value of CC is about 15%, the reduction of the value of CED is about 12%, and the reduction of FD value is about 28%. This analysis underlines the weakness of a tank-to-wheel comparison, according to which the pure electric powertrain, having a very high average efficiency, results in being the less consuming, followed by the hybrid gasoline-electric and fuel cell-battery vehicles, respectively, and then by the conventional vehicle. Instead, in terms of CED, the bad influence of the low average efficiency of the Italian electricity production is highlighted. The LCA approach also stresses out the importance of the battery inventory, which can make the environmental performance of the system based on the pure electric vehicle significantly worse than those based on the conventional vehicle. Of a great significance is the presence of a group of indicators—including human toxicity, eutrophication, and acidification—with lower values in the case of conventional gasoline vehicle than in the electric and hybrid ones, which further confirms that the potential of electrified vehicles strictly depends on an efficient production and recycling of the battery.

Conclusions

The analysis underlines an alarming list of environmental impact indicators, usually neglected, which are worsened by the powertrains electrification. Operating on the production processes, used materials and recycling phase can possibly mitigate these worsening effects. Also, the type of electricity is shown to strongly affect the results. Thus, performing specific evaluations for different countries is crucial and a sensitivity analysis, involving drastically different energy mixes, can allow for taking into account possible changes in the future electricity production.

     

Discovery of phenyl acetamides as potent and selective GPR119 agonists

The paper describes the SAR/SPR studies that led to the discovery of phenoxy cyclopropyl phenyl acetamide derivatives as potent and selective GPR119 agonists. Based on a cis cyclopropane scaffold discovered previously, phenyl acetamides such as compound 17 were found to have excellent GPR119 potency and improved physicochemical properties. Pharmacokinetic data of compound 17 in rat, dog and rhesus will be described. Compound 17 was suitable for QD dosing based on its predicted human half-life, and its projected human dose was much lower than that of the recently reported structurally-related benzyloxy compound 2. Compound 17 was selected as a tool compound candidate for NHP (Non-Human Primate) efficacy studies.     

Elastic energy storage in human articular cartilage: estimation of the elastic modulus for type II collagen and changes associated with osteoarthritis.

The viscoelastic mechanical properties of normal and osteoarthritic articular were analyzed based on data reported by Kempson [in: Adult Articular Cartilage (1973)] and Silver et al. (Connect. Tissue Res., 2001b). Results of the analysis of tensile elastic stress-strain curves suggest that the elastic modulus of cartilage from the superficial zone is approximately 7.0 GPa parallel and 2.21 GPa perpendicular to the cleavage line pattern. Collagen fibril lengths in the superficial zone were found to be approximately 1265 microm parallel and 668 microm perpendicular to the cleavage line direction. The values for the elastic modulus and fibril lengths decreased with increased extent of osteoarthritis. The elastic modulus of type II collagen parallel to the cleavage line pattern in the superficial zone approaches that of type I collagen in tendon, suggesting that elastic energy storage occurs in the superficial zone due to the tensile pre-tension that exists in this region. Decreases in the elastic modulus associated with osteoarthritis reflect decreased ability of cartilage to store elastic energy, which leads to cartilage fibrillation and fissure formation. We hypothesize that under normal physiological conditions, collagen fibrils in cartilage function to store elastic energy associated with weight bearing and locomotion. Enzymatic cleavage of cartilage proteoglycans and collagen observed in osteoarthritis may lead to fibrillation and fissure formation as a result of impaired energy storage capability of cartilage.