CLPP and EEA profiles of microbial communities in salt marsh sediments

Objective  Microbial communities are a central component of trophic dynamics and biogeochemical processes on coastal systems, since most of the processes in sediments are mediated by microorganisms and carried out by enzymes. Microorganisms play a key role in decomposition processes in salt marsh sediments, although the significance of microbial dynamics is largely unexplored. A culture-dependent (Ecoplate) and a culture-independent (extracellular enzyme activity [EEA]) approaches were evaluated in their ability to distinguish the catabolic potential among sediments from Tagus estuary salt marshes with different proximities to anthropogenic sources. Methods  Ecoplate was used to analyse the salt marsh community-level physiological profiles (CLPPs). Results were expressed as the net area under the curve for each of the 31 response wells over a 3-day incubation period in two sediment horizons. The catabolic profiles for salt marsh samples were analysed by Principal Component Analysis (PCA) and hierarchic clustering methods. EEA was analysed by fluorescein diacetate (FDA) hydrolysis in two sediment horizons. The FDA is catalysed by extracellular enzymes, i.e. esterases, lipases and partially by proteases. Results were expressed as μg g⁻¹d wt h⁻¹. Results and Discussion  In this study the CLPP and EEA data were not generally correlated. In Corroios salt marsh only in surface sediments higher net areas corresponded to higher extracellular enzymatic activity, and in Alcochete deep sediments lower net areas corresponded to lower enzymatic activity. Although EEA profiles more directly reflect the inherent activity of resident community in each salt marsh sample, the CLPP profiles provide better assessments of diversity. ESS-Submission Editor: Prof. Dr. Peter Schroeder, Institute of Soil Ecology, Department of Rhizosphere Biology, GSF — National Research Center for Environment & Health, Ingolstaedter Landstrasse 1, 85758 Neuherberg, Germany (peter.schroeder@gsf.de)     

Bottlenose dolphin (Tursiops truncatus) papillomaviruses: vaccine antigen candidates and screening test development

Papillomaviruses (PVs) have been shown as being the etiologic agents of various benign and malignant tumours in many vertebrate species. In dolphins and porpoises, a high prevalence of orogenital tumours has recently been documented with at least four distinct novel species-specific PV types detected in such lesions. Therefore, we generated the immunological reagents to establish a serological screening test to determine the prevalence of PV infection in Atlantic bottlenose dolphins [(Tursiops truncatus (Tt)]. Using the baculovirus expression system, virus-like particles (VLPs) derived from the L1 proteins of two TtPV types, TtPV1 and TtPV2, were generated. Polyclonal antibodies against TtPV VLPs were produced in rabbits and their specificity for the VLPs was confirmed. Electron microscopy and enzyme-linked immunosorbent assay (ELISA) studies revealed that the generated VLPs self-assembled into particles presenting conformational immunodominant epitopes. As such, these particles are potential antigen candidates for a TtPV vaccine. Subsequently, the VLPs served as antigens in initial ELISA tests using sera from six bottlenose dolphins to investigate PV antibody presence. Three of these sera were derived from dolphins with genital tumour history and showed positive PV ELISA reactivity, while the remaining sera from lesion-free dolphins were PV antibody-negative. The results suggest that the developed screening test may serve as a potential tool for determining PV prevalence and thus for observing transmission rates in dolphin populations as the significance of PV infection in cetaceans starts to unfold.     

Characterization of circulating lymphocyte subpopulations in canine leishmaniasis throughout treatment with antimonials and allopurinol

Canine leishmaniasis (CL) is a systemic parasitic disease with a wide variability of response to specific therapy: the majority of patients apparently improve with treatment, some of them respond but later relapse, and few of them do not respond at all. It has been demonstrated that the immune response plays a key role in the development and outcome of Leishmania infection in the dog and in the response to the treatment, although this response is not well understood. Some authors have suggested that ill dogs show a reduction in the percentage of circulating CD4+ lymphocytes and in the CD4+/CD8+ ratio, both of which normalize after treatment and clinical recovery. The present paper discusses the variation of the different lymphocyte subpopulations (CD3, CD4, CD8, CD21) of peripheral blood mononuclear cells (PBMC) in 28 dogs diagnosed with CL and submitted to conventional treatment with meglumine antimoniate (Glucantime) for 1 month and with allopurinol (Zyloric) for 1 year, in order to evaluate the usefulness of these parameters as indicators of the immunological condition of the ill animals and of the prognosis of their evolution during the treatment. It is concluded that circulating lymphocyte subpopulations are similar in dogs with leishmaniasis and in healthy dogs and that there is no correlation between the clinical status or response to therapy and the values of the counts of the different lymphocyte subpopulations. Therefore, the percentage of different lymphocyte subpopulations cannot be used as a parameter to predict the evolution of an individual patient in a clinical context.