Disassembly of Subplasmalemmal Actin Filaments Induces Cytosolic Ca2+ Increases in Astropecten aranciacus Eggs

Background/Aims: Eggs of all animal species display intense cytoplasmic Ca2+ increases at fertilization. Previously, we reported that unfertilized eggs of Astropecten aranciacus exposed to an actin drug latrunculin A (LAT-A) exhibit similar Ca2+ waves and cortical flashes after 5-10 min time lag. Here, we have explored the molecular mechanisms underlying this unique phenomenon. Methods: Starfish eggs were pretreated with various agents such as other actin drugs or inhibitors of phospholipase C (PLC), and the changes of the intracellular Ca2+ levels were monitored by use of Calcium Green in the presence or absence of LAT-A. The concomitant changes of the actin cytoskeleton were visualized with fluorescent F-actin probes in confocal microscopy. Results: We have shown that the LAT-A-induced Ca2+ increases are related to the disassembly of actin flaments: i) not only LAT-A but also other agents depolymerizing F-actin (i.e. cytochalasin B and mycalolide B) induced similar Ca2+ increases, albeit with slightly lower efficiency; ii) drugs stabilizing F-actin (i.e. phalloidin and jasplakinolide) either blocked or significantly delayed the LAT-A-induced Ca2+ increases. Further studies utilizing pharmacological inhibitors of PLC (U-73122 and neomycin), dominant negative mutant of PLC-ɣ, specific sequestration of PIP2 (RFP-PH), InsP3 uncaging, and quantitation of endogenous InsP3 all indicated that LAT-A induces Ca2+ increases by stimulating PLC rather than sensitizing InsP3 receptors. In support of the idea, it bears emphasis that LAT-A timely increased intracellular contents of InsP3 with concomitant decrease of PIP2 levels in the plasma membrane. Conclusion: Taken together, our results suggest that suboolemmal actin filaments may serve as a scaffold for cell signaling and modulate the activity of the key enzyme involved in intracellular Ca2+ signaling

Genetic analysis of the capsule polysaccharide (K antigen) and exopolysaccharide genes in pandemic Vibrio parahaemolyticus O3:K6

<p>Abstract</p> <p>Background</p> <p>Pandemic <it>Vibrio parahaemolyticus </it>has undergone rapid changes in both K- and O-antigens, making detection of outbreaks more difficult. In order to understand these rapid changes, the genetic regions encoding these antigens must be examined. In <it>Vibrio cholerae </it>and <it>Vibrio vulnificus</it>, both O-antigen and capsular polysaccharides are encoded in a single region on the large chromosome; a similar arrangement in pandemic <it>V. parahaemolyticus </it>would help explain the rapid serotype changes. However, previous reports on "capsule" genes are controversial. Therefore, we set out to clarify and characterize these regions in pandemic <it>V. parahaemolyticus </it>O3:K6 by gene deletion using a chitin based transformation strategy.</p> <p>Results</p> <p>We generated different deletion mutants of putative polysaccharide genes and examined the mutants by immuno-blots with O and K specific antisera. Our results showed that O- and K-antigen genes are separated in <it>V. parahaemolyticus </it>O3:K6; the region encoding both O-antigen and capsule biosynthesis in other vibrios, i.e. genes between <it>gmhD </it>and <it>rjg</it>, determines the K6-antigen but not the O3-antigen in <it>V. parahaemolyticus</it>. The previously identified "capsule genes" on the smaller chromosome were related to exopolysaccharide synthesis, not K-antigen.</p> <p>Conclusion</p> <p>Understanding of the genetic basis of O- and K-antigens is critical to understanding the rapid changes in these polysaccharides seen in pandemic <it>V. parahaemolyticus. </it>This report confirms the genetic location of K-antigen synthesis in <it>V. parahaemolyticus </it>O3:K6 allowing us to focus future studies of the evolution of serotypes to this region.</p

Histone Deacetylase Inhibitors Impair the Elimination of HIV-Infected Cells by Cytotoxic T-Lymphocytes

Resting memory CD4+ T-cells harboring latent HIV proviruses represent a critical barrier to viral eradication. Histone deacetylase inhibitors (HDACis), such as suberanilohydroxamic acid (SAHA), romidepsin, and panobinostat have been shown to induce HIV expression in these resting cells. Recently, it has been demonstrated that the low levels of viral gene expression induced by a candidate HDACi may be insufficient to cause the death of infected cells by viral cytopathic effects, necessitating their elimination by immune effectors, such as cytotoxic T-lymphocytes (CTL). Here, we study the impact of three HDACis in clinical development on T-cell effector functions. We report two modes of HDACi-induced functional impairment: i) the rapid suppression of cytokine production from viable T-cells induced by all three HDACis ii) the selective death of activated T-cells occurring at later time-points following transient exposures to romidepsin or, to a lesser extent, panobinostat. As a net result of these factors, HDACis impaired CTL-mediated IFN-γ production, as well as the elimination of HIV-infected or peptide-pulsed target cells, both in liquid culture and in collagen matrices. Romidepsin exerted greater inhibition of antiviral function than SAHA or panobinostat over the dose ranges tested. These data suggest that treatment with HDACis to mobilize the latent reservoir could have unintended negative impacts on the effector functions of CTL. This could influence the effectiveness of HDACi-based eradication strategies, by impairing elimination of infected cells, and is a critical consideration for trials where therapeutic interruptions are being contemplated, given the importance of CTL in containing rebound viremia

Severe traumatic injury during long duration spaceflight: Light years beyond ATLS

Traumatic injury strikes unexpectedly among the healthiest members of the human population, and has been an inevitable companion of exploration throughout history. In space flight beyond the Earth's orbit, NASA considers trauma to be the highest level of concern regarding the probable incidence versus impact on mission and health. Because of limited resources, medical care will have to focus on the conditions most likely to occur, as well as those with the most significant impact on the crew and mission. Although the relative risk of disabling injuries is significantly higher than traumatic deaths on earth, either issue would have catastrophic implications during space flight. As a result this review focuses on serious life-threatening injuries during space flight as determined by a NASA consensus conference attended by experts in all aspects of injury and space flight

Photorealistic style transfer via wavelet transforms

Recent style transfer models have provided promising artistic results. However, given a photograph as a reference style, existing methods are limited by spatial distortions or unrealistic artifacts, which should not happen in real photographs. We introduce a theoretically sound correction to the network architecture that remarkably enhances photorealism and faithfully transfers the style. The key ingredient of our method is wavelet transforms that naturally fits in deep networks. We propose a wavelet corrected transfer based on whitening and coloring transforms (WCT2) that allows features to preserve their structural information and statistical properties of VGG feature space during stylization. This is the first and the only end-to-end model that can stylize a 1024x1024 resolution image in 4.7 seconds, giving a pleasing and photorealistic quality without any post-processing. Last but not least, our model provides a stable video stylization without temporal constraints. Our code, generated images, pre-trained models and supplementary documents are all available at https://github.com/ClovaAI/WCT2