Synthesis of 2'-C-methyl-beta-D-ribofuranosylimidazo [4,5-d]-pyridazine derivatives (2-aza-3-deazapurine nucleoside analogues)

In order to evaluate their antiviral properties, two imidazo[4,5-d]pyridazine 2'-C-methyl-beta-D-ribofuranonucleoside derivatives have been synthesized.     

Standardization of MspI and HaeIII restriction karyotypes in cattle

Cattle chromosomes were digested with two restriction endonucleases, MspI and HaeIII. The banding pattern induced by each enzyme allowed the identification and pairing of all individual chromosomes and consequently the elaboration of the karyotype. This method is rapid and technically easy, and proved to be of great utility in cattle cytogenetic studies.     

Optimizing thermal imaging as a technique for detecting stomatal closure induced by drought stress under greenhouse conditions

Temperature of leaves or canopies can be used as an indicator of stomatal aperture, which is considered a sensitive response to soil water deficit. In this paper we analyse the robustness and sensitivity of thermal imaging for detecting changes in stomatal conductance and leaf water status in a range of plant species. Thermal imaging successfully distinguished between irrigated and non-irrigated plants of a variety of species under greenhouse or controlled chamber conditions, with strong correlations between thermal indices and stomatal conductance measured by porometry. Our results also highlighted issues that need to be addressed in order to be confident of always detecting drought stress using this technique. These include variability in leaf angles and the limited reliability of 'wet' and 'dry' leaves to represent leaves with stomata fully open or stomata fully closed. These results should assist the design of protocols for application in crop production or ecosystem monitoring.     

Paleoparasitological remains revealed by seven historic contexts from "Place d'Armes", Namur, Belgium

Human occupation for several centuries was recorded in the archaeological layers of "Place d'Armes", Namur, Belgium. Preventive archaeological excavations were carried out between 1996/1997 and seven historical strata were observed, from Gallo-Roman period up to Modern Times. Soil samples from cesspools, latrines, and structures-like were studied and revealed intestinal parasite eggs in the different archaeological contexts. Ascaris lumbricoides, A. suum, Trichuris trichiura, T. suis. Taenia sp., Fasciola hepatica, Diphyllobothrium sp., Capillaria sp. and Oxyuris equi eggs were found. Paleoparasitology confirmed the use of structures as latrines or cesspit as firstly supposed by the archaeologists. Medieval latrines were not only used for rejection of human excrements. The finding of Ascaris sp. and Trichuris sp. eggs may point to human's or wild swine's feces. Gallo-Roman people used to eat wild boar. Therefore, both A. suum and T. suis, or A. lumbricoides and T. trichuris, may be present, considering a swine carcass recovered into a cesspit. Careful sediment analysis may reveal its origin, although parasites of domestic animals can be found together with those of human's. Taenia sp. eggs identified in latrine samples indicate ingestion of uncooked beef with cysticercoid larvae. F. hepatica eggs suggest the ingestion of raw contaminated vegetables and Diphyllobothrium sp. eggs indicate contaminated fresh-water fish consumption. Ascaris sp. and Trichuris sp. eggs indicate fecal-oral infection by human and/or animal excrements.     

Selection and validation of reference sites in small river basins

Type-specific reference conditions that describe sites with no or only very minor anthropogenic disturbances are a basic requirement of the European Water Framework Directive. The reference condition approach implies a previous determination of criteria acceptable for the definition of near-natural stretches. In this paper, a methodology based on selection and validation procedures is applied to a Portuguese watershed to guide the identification of reference sites. The methodology consisted of three phases: (1) a preliminary site inspection through the use of maps, available data and an extensive screening field campaign that resulted in the selection of 52 potentially undisturbed small- and medium-sized rivers stretches, ranging from 43 to 1069 m in altitude, with catchment areas between 4 and 641 km² and representing siliceous and calcareous riverbeds; (2) a detailed site selection based on ten pre-defined criteria involving physical/social/biological attributes that indicated catchment land use changes and alien vegetal riparian species as major human impacts; (3) a site validation procedure involving detailed investigation of benthic macroinvertebrate communities, riparian vegetation, in-stream habitat quality and chemical parameters that showed riparian wood-related problems as a major restriction to validate a stretch as a near-natural site. Only about 12% of all investigated river sites, accounting for 600 m of all 5200 m studied, could be considered as near-reference stretches or sites retaining essential natural functions. Selection and validation procedures can identify different sites as reference, which reinforces the need for applying both procedures. The results presented can help to accomplish the requirements of the EU – Water Framework Directive by selecting reference sites as the first step to establish biological reference conditions and, simultaneously, to form a basis for nature conservation strategies. Electronic supplementary material Electronic supplementary material is available for this article at and accessible for authorised users.     

Immune adaptive response induced by Bicotylophora trachinoti (Monogenea: Diclidophoridae) infestation in pompano Trachinotus marginatus (Perciformes: Carangidae)

Fish have developed protective strategies against monogeneans through immunological responses. In this study, immune adaptive response to parasites was analysed in the pompano Trachinotus marginatus infested by Bicotylophora trachinoti. Hosts were pre-treated with formalin and after 10 days assigned to one of the following experimental treatments: (1) fish infested with remaining eggs of B. trachinoti; (2) fish infested with remaining eggs of B. trachinoti and experimentally re-infested by exposure to T. marginatus heavily infested with B. trachinoti. Samples were collected at 0, 15, and 30 days. Gills were dissected to check the presence of B. trachinoti. Blood was collected for haematological and biochemical assays. Spleen and head-kidney were dissected for phagocytosis assay. The spleen-somatic index was also calculated. Re-infested fish showed a faster and higher parasite infestation than infested ones. The parasite mean abundance at 15 days was 24.86+/-13.32 and 11.67+/-8.57 for re-infested and infested fish, respectively. In both groups, hosts showed an immune adaptive response to parasite infestation that was marked by an increased number of leukocytes. Also, phagocytosis (%) in spleen and head-kidney cells was stimulated after parasite infestation (92.50+/-3.73 and 66.00+/-9.54, respectively), becoming later depressed (77.39+/-6.69 and 53.23+/-9.14, respectively). These results support the hypothesis that monogenean infestation induces a biphasic response of the non-specific defence mechanisms in the pompano T. marginatus. This response is marked by an initial stimulation followed by a later depression of the non-specific defence mechanisms.