A novel PKC activating molecule promotes neuroblast differentiation and delivery of newborn neurons in brain injuries

Neural stem cells are activated within neurogenic niches in response to brain injuries. This results in the production of neuroblasts, which unsuccessfully attempt to migrate toward the damaged tissue. Injuries constitute a gliogenic/non-neurogenic niche generated by the presence of anti-neurogenic signals, which impair neuronal differentiation and migration. Kinases of the protein kinase C (PKC) family mediate the release of growth factors that participate in different steps of the neurogenic process, particularly, novel PKC isozymes facilitate the release of the neurogenic growth factor neuregulin. We have demonstrated herein that a plant derived diterpene, (EOF2; CAS number 2230806-06-9), with the capacity to activate PKC facilitates the release of neuregulin 1, and promotes neuroblasts differentiation and survival in cultures of subventricular zone (SVZ) isolated cells in a novel PKC dependent manner. Local infusion of this compound in mechanical cortical injuries induces neuroblast enrichment within the perilesional area, and noninvasive intranasal administration of EOF2 promotes migration of neuroblasts from the SVZ towards the injury, allowing their survival and differentiation into mature neurons, being some of them cholinergic and GABAergic. Our results elucidate the mechanism of EOF2 promoting neurogenesis in injuries and highlight the role of novel PKC isozymes as targets in brain injury regeneration

Specific requirement of NMDA receptors for long-term memory consolidation in Drosophila ellipsoid body

In humans and many other animals, memory consolidation occurs through multiple temporal phases and usually involves more than one neuroanatomical brain system. Genetic dissection of Pavlovian olfactory learning in Drosophila melanogaster has revealed multiple memory phases, but the predominant view holds that all memory phases occur in mushroom body neurons. Here, we demonstrate an acute requirement for NMDA receptors (NMDARs) outside of the mushroom body during long-term memory (LTM) consolidation. Targeted dsRNA-mediated silencing of Nmdar1 and Nmdar2 (also known as dNR1 or dNR2, respectively) in cholinergic R4m-subtype large-field neurons of the ellipsoid body specifically disrupted LTM consolidation, but not retrieval. Similar silencing of functional NMDARs in the mushroom body disrupted an earlier memory phase, leaving LTM intact. Our results clearly establish an anatomical site outside of the mushroom body involved with LTM consolidation, thus revealing both a distributed brain system subserving olfactory memory formation and the existence of a system-level memory consolidation in Drosophila

Reactions of Cre with Methylphosphonate DNA: Similarities and Contrasts with Flp and Vaccinia Topoisomerase

Chien-Hui Ma is with UT Austin, Aashiq H. Kachroo is with UT Austin, Anna Macieszak is with Polish Academy of Sciences, Tzu-Yang Chen is with UT Austin, Piotr Guga is with Polish Academy of Sciences, Makkuni Jayaram is with UT Austin.Background -- Reactions of vaccinia topoisomerase and the tyrosine site-specific recombinase Flp with methylphosphonate (MeP) substituted DNA substrates, have provided important insights into the electrostatic features of the strand cleavage and strand joining steps catalyzed by them. A conserved arginine residue in the catalytic pentad, Arg-223 in topoisomerase and Arg-308 in Flp, is not essential for stabilizing the MeP transition state. Topoisomerase or its R223A variant promotes cleavage of the MeP bond by the active site nucleophile Tyr-274, followed by the rapid hydrolysis of the MeP-tyrosyl intermediate. Flp(R308A), but not wild type Flp, mediates direct hydrolysis of the activated MeP bond. These findings are consistent with a potential role for phosphate electrostatics and active site electrostatics in protecting DNA relaxation and site-specific recombination, respectively, against abortive hydrolysis. Methodology/Principal Findings -- We have examined the effects of DNA containing MeP substitution in the Flp related Cre recombination system. Neutralizing the negative charge at the scissile position does not render the tyrosyl intermediate formed by Cre susceptible to rapid hydrolysis. Furthermore, combining the active site R292A mutation in Cre (equivalent to the R223A and R308A mutations in topoisomerase and Flp, respectively) with MeP substitution does not lead to direct hydrolysis of the scissile MeP bond in DNA. Whereas Cre follows the topoisomerase paradigm during the strand cleavage step, it follows the Flp paradigm during the strand joining step. Conclusions/Significance -- Collectively, the Cre, Flp and topoisomerase results highlight the contribution of conserved electrostatic complementarity between substrate and active site towards transition state stabilization during site-specific recombination and DNA relaxation. They have potential implications for how transesterification reactions in nucleic acids are protected against undesirable abortive side reactions. Such protective mechanisms are significant, given the very real threat of hydrolytic genome damage or disruption of RNA processing due to the cellular abundance and nucleophilicity of water.This work was supported by the NIH award GM035654 to M. J. Partial support was provided by the Robert F. Welch Foundation (F-1274) and a Faculty Research Award from the University of Texas at Austin. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Microbiolog

Effective Rheology of Bubbles Moving in a Capillary Tube

We calculate the average volumetric flux versus pressure drop of bubbles moving in a single capillary tube with varying diameter, finding a square-root relation from mapping the flow equations onto that of a driven overdamped pendulum. The calculation is based on a derivation of the equation of motion of a bubble train from considering the capillary forces and the entropy production associated with the viscous flow. We also calculate the configurational probability of the positions of the bubbles.Comment: 4 pages, 1 figur

A Functional Nuclear Localization Sequence in the C. elegans TRPV Channel OCR-2

The ability to modulate gene expression in response to sensory experience is critical to the normal development and function of the nervous system. Calcium is a key activator of the signal transduction cascades that mediate the process of translating a cellular stimulus into transcriptional changes. With the recent discovery that the mammalian Cav1.2 calcium channel can be cleaved, enter the nucleus and act as a transcription factor to control neuronal gene expression, a more direct role for the calcium channels themselves in regulating transcription has begun to be appreciated. Here we report the identification of a nuclear localization sequence (NLS) in the C. elegans transient receptor potential vanilloid (TRPV) cation channel OCR-2. TRPV channels have previously been implicated in transcriptional regulation of neuronal genes in the nematode, although the precise mechanism remains unclear. We show that the NLS in OCR-2 is functional, being able to direct nuclear accumulation of a synthetic cargo protein as well as the carboxy-terminal cytosolic tail of OCR-2 where it is endogenously found. Furthermore, we discovered that a carboxy-terminal portion of the full-length channel can localize to the nucleus of neuronal cells. These results suggest that the OCR-2 TRPV cation channel may have a direct nuclear function in neuronal cells that was not previously appreciated

Gene Targeting Implicates Cdc42 GTPase in GPVI and Non-GPVI Mediated Platelet Filopodia Formation, Secretion and Aggregation

Background: Cdc42 and Rac1, members of the Rho family of small GTPases, play critical roles in actin cytoskeleton regulation. We have shown previously that Rac1 is involved in regulation of platelet secretion and aggregation. However, the role of Cdc42 in platelet activation remains controversial. This study was undertaken to better understand the role of Cdc42 in platelet activation. Methodology/Principal Findings: We utilized the Mx-cre;Cdc42 lox/lox inducible mice with transient Cdc42 deletion to investigate the involvement of Cdc42 in platelet function. The Cdc42-deficient mice exhibited a significantly reduced platelet count than the matching Cdc42 +/+ mice. Platelets isolated from Cdc42 2/2, as compared to Cdc42 +/+, mice exhibited (a) diminished phosphorylation of PAK1/2, an effector molecule of Cdc42, (b) inhibition of filopodia formation on immobilized CRP or fibrinogen, (c) inhibition of CRP- or thrombin-induced secretion of ATP and release of P-selectin, (d) inhibition of CRP, collagen or thrombin induced platelet aggregation, and (e) minimal phosphorylation of Akt upon stimulation with CRP or thrombin. The bleeding times were significantly prolonged in Cdc42 2/2 mice compared with Cdc42 +/+ mice. Conclusion/Significance: Our data demonstrate that Cdc42 is required for platelet filopodia formation, secretion an

Implication of 4E-BP1 protein dephosphorylation and accumulation in pancreatic cancer cell death induced by combined gemcitabine and TRAIL

Pancreatic cancer cells show varying sensitivity to the anticancer effects of gemcitabine. However, as a chemotherapeutic agent, gemcitabine can cause intolerably high levels of toxicity and patients often develop resistance to the beneficial effects of this drug. Combination studies show that use of gemcitabine with the pro-apoptotic cytokine TRAIL can enhance the inhibition of survival and induction of apoptosis of pancreatic cancer cells. Additionally, following combination treatment there is a dramatic increase in the level of the hypophosphorylated form of the tumour suppressor protein 4E-BP1. This is associated with inhibition of mTOR activity, resulting from caspase-mediated cleavage of the Raptor and Rictor components of mTOR. Use of the pan-caspase inhibitor Z-VAD-FMK indicates that the increase in level of 4E-BP1 is also caspase-mediated. ShRNA-silencing of 4E-BP1 expression renders cells more resistant to cell death induced by the combination treatment. Since the levels of 4E-BP1 are relatively low in untreated pancreatic cancer cells these results suggest that combined therapy with gemcitabine and TRAIL could improve the responsiveness of tumours to treatment by elevating the expression of 4E-BP1

Mitochondrial respiratory states and rate

As the knowledge base and importance of mitochondrial physiology to human health expands, the necessity for harmonizing the terminologyconcerning mitochondrial respiratory states and rates has become increasingly apparent. Thechemiosmotic theoryestablishes the mechanism of energy transformationandcoupling in oxidative phosphorylation. Theunifying concept of the protonmotive force providestheframeworkfordeveloping a consistent theoretical foundation ofmitochondrial physiology and bioenergetics.We followguidelines of the International Union of Pure and Applied Chemistry(IUPAC)onterminology inphysical chemistry, extended by considerationsofopen systems and thermodynamicsof irreversible processes.Theconcept-driven constructive terminology incorporates the meaning of each quantity and alignsconcepts and symbols withthe nomenclature of classicalbioenergetics. We endeavour to provide a balanced view ofmitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes.Uniform standards for evaluation of respiratory states and rates will ultimatelycontribute to reproducibility between laboratories and thussupport the development of databases of mitochondrial respiratory function in species, tissues, and cells.Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

The dominant Anopheles vectors of human malaria in the Asia-Pacific region: occurrence data, distribution maps and bionomic précis

<p>Abstract</p> <p>Background</p> <p>The final article in a series of three publications examining the global distribution of 41 dominant vector species (DVS) of malaria is presented here. The first publication examined the DVS from the Americas, with the second covering those species present in Africa, Europe and the Middle East. Here we discuss the 19 DVS of the Asian-Pacific region. This region experiences a high diversity of vector species, many occurring sympatrically, which, combined with the occurrence of a high number of species complexes and suspected species complexes, and behavioural plasticity of many of these major vectors, adds a level of entomological complexity not comparable elsewhere globally. To try and untangle the intricacy of the vectors of this region and to increase the effectiveness of vector control interventions, an understanding of the contemporary distribution of each species, combined with a synthesis of the current knowledge of their behaviour and ecology is needed.</p> <p>Results</p> <p>Expert opinion (EO) range maps, created with the most up-to-date expert knowledge of each DVS distribution, were combined with a contemporary database of occurrence data and a suite of open access, environmental and climatic variables. Using the Boosted Regression Tree (BRT) modelling method, distribution maps of each DVS were produced. The occurrence data were abstracted from the formal, published literature, plus other relevant sources, resulting in the collation of DVS occurrence at 10116 locations across 31 countries, of which 8853 were successfully geo-referenced and 7430 were resolved to spatial areas that could be included in the BRT model. A detailed summary of the information on the bionomics of each species and species complex is also presented.</p> <p>Conclusions</p> <p>This article concludes a project aimed to establish the contemporary global distribution of the DVS of malaria. The three articles produced are intended as a detailed reference for scientists continuing research into the aspects of taxonomy, biology and ecology relevant to species-specific vector control. This research is particularly relevant to help unravel the complicated taxonomic status, ecology and epidemiology of the vectors of the Asia-Pacific region. All the occurrence data, predictive maps and EO-shape files generated during the production of these publications will be made available in the public domain. We hope that this will encourage data sharing to improve future iterations of the distribution maps.</p

Alignment of the ALICE Inner Tracking System with cosmic-ray tracks

37 pages, 15 figures, revised version, accepted by JINSTALICE (A Large Ion Collider Experiment) is the LHC (Large Hadron Collider) experiment devoted to investigating the strongly interacting matter created in nucleus-nucleus collisions at the LHC energies. The ALICE ITS, Inner Tracking System, consists of six cylindrical layers of silicon detectors with three different technologies; in the outward direction: two layers of pixel detectors, two layers each of drift, and strip detectors. The number of parameters to be determined in the spatial alignment of the 2198 sensor modules of the ITS is about 13,000. The target alignment precision is well below 10 micron in some cases (pixels). The sources of alignment information include survey measurements, and the reconstructed tracks from cosmic rays and from proton-proton collisions. The main track-based alignment method uses the Millepede global approach. An iterative local method was developed and used as well. We present the results obtained for the ITS alignment using about 10^5 charged tracks from cosmic rays that have been collected during summer 2008, with the ALICE solenoidal magnet switched off.Peer reviewe