Identification of a Gal/GalNAc Lectin in the Protozoan \u3cem\u3eHartmannella vermiformis\u3c/em\u3e as a Potential Receptor for Attachment and Invasion by the Legionnaires\u27 Disease Bacterium

The Legionnaire\u27s disease bacterium, Legionella pneumophila, is a facultative intracellular pathogen which invades and replicates within two evolutionarily distant hosts, free-living protozoa and mammalian cells. Invasion and intracellular replication within protozoa are thought to be major factors in the transmission of Legionnaire\u27s disease. Although attachment and invasion of human macrophages by L. pneumophila is mediated in part by the complement receptors CR1 and CR3, the protozoan receptor involved in bacterial attachment and invasion has not been identified. To define the molecular events involved in invasion of protozoa by L. pneumophila, we examined the role of protein tyrosine phosphorylation of the protozoan host Hartmannella vermiformis upon attachment and invasion by L. pneumophila. Bacterial attachment and invasion were associated with a time-dependent tyrosine dephosphorylation of multiple host cell proteins. This host cell response was highly specific for live L. pneumophila, required contact with viable bacteria, and was completely reversible following washing off the bacteria from the host cell surface. Tyrosine dephosphorylation of host proteins was blocked by a tyrosine phosphatase inhibitor but not by tyrosine kinase inhibitors. One of the tyrosine dephosphorylated proteins was identified as the 170-kD galactose/N-acetylgalactosamine–inhibitable lectin (Gal/GalNAc) using immunoprecipitation and immunoblotting by antibodies generated against the Gal/GalNAc lectin of the protozoan Entamoeba histolytica. This Gal/GalNAc–inhibitable lectin has been shown previously to mediate adherence of E. histolytica to mammalian epithelial cells. Uptake of L. pneumophila by H. vermiformis was specifically inhibited by two monovalent sugars, Gal and GalNAc, and by mABs generated against the 170-kD lectin of E. histolytica. Interestingly, inhibition of invasion by Gal and GalNAc was associated with inhibition of bacterial-induced tyrosine dephosphorylation of H. vermiformis proteins. High stringency DNA hybridization confirmed the presence of the 170-kD lectin gene in H. vermiformis. We conclude that attachment of L. pneumophila to the H. vermiformis 170-kD lectin is required for invasion and is associated with tyrosine dephosphorylation of the Gal lectin and other host proteins. This is the first demonstration of a potential receptor used by L. pneumophila to invade protozoa

Cloning and functional characterization of the rabbit C-C chemokine receptor 2

BACKGROUND: CC-family chemokine receptor 2 (CCR2) is implicated in the trafficking of blood-borne monocytes to sites of inflammation and is implicated in the pathogenesis of several inflammatory diseases such as rheumatoid arthritis, multiple sclerosis and atherosclerosis. The major challenge in the development of small molecule chemokine receptor antagonists is the lack of cross-species activity to the receptor in the preclinical species. Rabbit models have been widely used to study the role of various inflammatory molecules in the development of inflammatory processes. Therefore, in this study, we report the cloning and characterization of rabbit CCR2. Data regarding the activity of the CCR2 antagonist will provide valuable tools to perform toxicology and efficacy studies in the rabbit model. RESULTS: Sequence alignment indicated that rabbit CCR2 shares 80 % identity to human CCR2b. Tissue distribution indicated that rabbit CCR2 is abundantly expressed in spleen and lung. Recombinant rabbit CCR2 expressed as stable transfectants in U-937 cells binds radiolabeled (125)I-mouse JE (murine MCP-1) with a calculated K(d )of 0.1 nM. In competition binding assays, binding of radiolabeled mouse JE to rabbit CCR2 is differentially competed by human MCP-1, -2, -3 and -4, but not by RANTES, MIP-1α or MIP-1β. U-937/rabbit CCR2 stable transfectants undergo chemotaxis in response to both human MCP-1 and mouse JE with potencies comparable to those reported for human CCR2b. Finally, TAK-779, a dual CCR2/CCR5 antagonist effectively inhibits the binding of (125)I-mouse JE (IC(50 )= 2.3 nM) to rabbit CCR2 and effectively blocks CCR2-mediated chemotaxis. CONCLUSION: In this study, we report the cloning of rabbit CCR2 and demonstrate that this receptor is a functional chemotactic receptor for MCP-1

A systematic review of coastal vulnerability assessment studies along Andhra Pradesh, India: A critical evaluation of data gathering, risk levels and mitigation strategies

The establishment and alteration of any coastal feature is largely dependent upon complex hydrological and geomorphologic processes. Therefore, understanding hazard factors and threat risk level is crucial for mitigating risk in coastal zones. This study examines coastal vulnerability factors and their influence along the Coastal Andhra Pradesh (CAP) region in India. CAP has been exposed to frequent hydrological and meteorological hazards due to variations in the geographical, geological, and bathymetric characteristics. Despite substantial vulnerabilities, the risk to the coastline of Andhra Pradesh has not been rigorously evaluated. The current research systematically reviews the drivers and effects of hazards and vulnerabilities in CAP. Findings indicate that urban cities have a considerably higher risk of cyclones and floods due to their locations on the Bay of Bengal tectonic plate, the topology of this coastal region and higher population density. The study revealed that the Coastal Vulnerability Index (CVI) data along CAP is mostly gathered using low-resolution satellite data and/or field observation surveys. The study further revealed that there are very few existing mitigation strategies developed or discussed within the obtained results. However, more accurate data gathering techniques for coastal vulnerability factors are available such as Unmanned Aerial Vehicles (UAVs): Air-borne and LiDAR sensors which provide very high resolution data and low-cost accessibility to physically inaccessible places, making them suitable for vulnerability data collection in coastal locations. These findings are useful for stakeholders seeking to reduce or ameliorate the impact of coastal disasters and their impacts on the CAP economy, environment and population. The study further helps to reduce the existing shortcomings in the assessment techniques used previously

New Observation of Intertwined Annulated Sea Snake Hydrophis cyanocinctus (Reptilia: Elaphidae: Hydrophiinae) from Pirotan Island, Gulf of Kachchh

2465-2468New evidence of species from an explored area extends its range of distribution and provides valuable information on the biodiversity conservation management. Here we reported observations on the sex of annulated sea snake, Hydrophis cyanocinctus, during May 2014, but previous copulations were reported during January to February. Mean snout-vent length (SVL) was a male 105 cm and the largest snake was a female with an SVL 145 cm and weight 910.5 g. The specimen has been compared with earlier reports and other similar species. These findings are among the first to be recorded in some species of sea snakes in the Indian region. In this present report preliminary observations on the sex, reproductive status of species hydrophiine sea snakes from Gujarat coastal regions, India