Chemistry of the Nudibranch Aldisa andersoni: Structure and Biological Activity of Phorbazole Metabolites

The first chemical study of the Indo-Pacific dorid nudibranch Aldisa andersoni resulted in the isolation of five chlorinated phenyl-pyrrolyloxazoles belonging to the phorbazole series. Two new molecules, 9-chloro-phorbazole D and N1-methyl-phorbazole A, co-occurring with known phorbazoles A, B and D, have been characterized. Phorbazoles were found to be present mainly in the external part of the mollusc. The structures of the new compounds were determined by interpretation of spectroscopic data, mainly NMR and mass spectrometry and by comparison with the literature data. Evaluation of feeding-deterrence activity as well as in vitro growth inhibitory properties in human cancer cells was also carried out.     

White spot syndrome virus: an overview on an emergent concern

Viruses are ubiquitous and extremely abundant in the marine environment. One of such marine viruses, the white spot syndrome virus (WSSV), has emerged globally as one of the most prevalent, widespread and lethal for shrimp populations. However, at present there is no treatment available to interfere with the unrestrained occurrence and spread of the disease. The recent progress in molecular biology techniques has made it possible to obtain information on the factors, mechanisms and strategies used by this virus to infect and replicate in susceptible host cells. Yet, further research is still required to fully understand the basic nature of WSSV, its exact life cycle and mode of infection. This information will expand our knowledge and may contribute to developing effective prophylactic or therapeutic measures. This review provides a state-of-the-art overview of the topic, and emphasizes the current progress and future direction for the development of WSSV control strategies.     

Virulence-associated trimeric autotransporters of Haemophilus parasuis are antigenic proteins expressed in vivo

Glässer’s disease is a re-emerging swine disease characterized by a severe septicaemia. Vaccination has been widely used to control the disease, although there is a lack of extended cross-protection. Trimeric autotransporters, a family of surface exposed proteins implicated in host-pathogen interactions, are good vaccine candidates. Members of this family have been described in Haemophilus parasuis and designated as virulence-associated trimeric autotransporters (VtaA). In this work, we produced 15 recombinant VtaA passenger domains and looked for the presence of antibodies directed against them in immune sera by immunoblotting. After infection with a subclinical dose of H. parasuis Nagasaki, an IgG mediated antibody response against 6 (VtaA1, 5, 6, 8, 9 and 10) of the 13 VtaA of the Nagasaki strain was detected, indicating that they are expressed in vivo. IgA production against VtaA was detected in only one animal. VtaA were more likely to be late antigens when compared to early (Omp P5 and Omp P6) and late (YaeT) defined antigens. Antibody cross-reaction with two orthologs of Nagasaki’s VtaA5 and 6, VtaA15 and 16 of strain HP1319, was also detected. No antibodies against VtaA were detected in the sera of animals immunized with a bacterin of the Nagasaki strain, suggesting poor expression in the in vitro conditions used. Taken together, these results indicate that VtaA are good candidate immunogens that could be used to improve H. parasuis vaccines. However, their capacity to confer protective immunity needs to be further studied.     

Sulphur supply impairs spread of Verticillium dahliae in tomato

Vascular wilt caused by the soil-borne fungus Verticillium dahliae is a major yield and quality-limiting disease across a broad spectrum of crop plants worldwide. Sulphur-enhanced plant defence mechanisms provide an opportunity to effectively and environmentally safely constrain the wilt disease levels in planta. To evaluate the influence of sulphur nutrition on the protective potential of these mechanisms, two near-isogenic tomato genotypes differing in fungal susceptibility, were treated with low or supra-optimal sulphur supply. Microscopic analysis revealed a significant sulphur-induced decrease in the amount of infected vascular cells in both genotypes. However, plant shoot and severely pathogen-affected root growth did not display this distinct alleviating influence of sulphur nutrition. Rates of leaf photosynthesis were impeded by Verticillium dahliae infection in both genotypes especially under low sulphur nutrition. However, assimilate transport rates in the phloem sap were enhanced by fungal infection more in the resistant genotype and under high sulphur nutrition suggesting a stronger sink for assimilates in infected plant tissues possibly involved in sugar-induced defence. A SYBR Green-based absolute quantitative Real-Time assay using a species-specific primer was developed which sensitively reflected sulphur nutrition-dependent changes in fungal colonization patterns. High sulphur nutrition significantly reduced fungal spread in the stem in both tomato genotypes. Concentrations of selected sulphur-containing metabolites revealed an increase of the major anti-oxidative redox buffer glutathione under high sulphur nutrition in response to fungal colonization. Our study demonstrates the existence of sulphur nutrition-enhanced resistance of tomato against Verticillium dahliae mediated by sulphur-containing defence compounds.     

Germination differentiation patterns of wild and domesticated columnar cacti in a gradient of artificial selection intensity

Germination of wild and managed populations of columnar cacti was compared to analyze differences associated to management intensity. The species studied: Polaskia chende, Escontria chiotilla, Myrtillocactus schenckii, Polaskia chichipe, and Stenocereus pruinosus are in a gradient from lower to higher management intensity, respectively. Within each species wild, silvicultural, and cultivated populations also represent a gradient from lower to higher management intensity. We hypothesized that seeds of plants under higher management intensity would require more water to germinate than others since managed environments are relatively wetter than unmanaged environments. Such pattern could be visualized within and among species according to management intensity. We tested germination of seeds from different populations of the different species to the water potentials: 0.0, ?0.2, ?0.4, ?0.6, ?0.8, and ?1.0 MPa. In all species studied seeds of managed populations had significantly more mass than seeds from wild populations. Each species had different susceptibility to water availability decrease, which could be related to particular adaptations to drought resistance. Stenocereus pruinosus and Polaskia chende were the most and least susceptible species, respectively. In control treatments of all species, seeds of managed populations had higher germination rate than seeds from wild populations, but when water availability decreased the pattern was the contrary. Our results suggest that artificial selection for larger fruits and heavier seeds in plants established in wetter environments have affected germination patterns. Although species have particular critical points of water availability for germination, differences in germination patterns are more pronounced according to management and artificial selection intensity.     

Dynamics of Atmospheric Aerosol Number Size Distributions in the Eastern Mediterranean During the ��SUB-AERO�� Project

Measurements of number size distributions of submicron aerosols have been performed at the Eastern part of Mediterranean as part of an extensive measurement campaign to study photo-oxidants and aerosols (SUB-AERO Project). The measurements were made at the Finokalia station on the island of Crete (Greece) and onboard the research vessel ??Aegaeon??. Two campaigns were performed during July 2000 and January 2001 using two scanning mobility particle sizers. The particle distributions measured in the range between 7.8 < d _p < 327 nm during the summer measurements and between 7.5 < d _p < 316 nm during the winter measurements, where d _p is the mobility particle diameter. The concentration of ultrafine particles (7.5 < d _p < 30 nm) was higher during the winter period and varied mainly between 5 × 10¹ and 2 × 10³?cm^?3 with concentration peak values for this mode exceeding 1 × 10⁴?cm^?3. During the summer campaign, an average number concentration of 1 × 10²?cm^?3 at Finokalia and about 5 × 10¹?cm^?3 aboard the ??Aegaeon?? vessel was measured. An average concentration of 1 × 10³?cm^?3 was measured for the particles in the size range between 30 and 100 nm, whereas in the size range 100?C300 nm, the measured concentration ranged between 1 × 10² and 5 × 10³?cm^?3. Diurnal patterns in number concentrations were observed in connection with the transport of air masses and local sources. During the winter period, three nucleation events were observed in connection with the appearance of a particle mode at 20 nm.     

Evaluation of Deammonification Process by Response Surface Models

The influence of the operational variables on the Anammox process has been generally researched considering each variable separately. However, the optimization of the process also requires the identification of the more significant variables and their possible interactions. Response surface models were successfully applied to evaluate the performance of the Anammox process in a deammonification system (i.e., one-stage biofilm Anammox process) taking into account the combined effects caused by two sets of three variables. Specific Anammox activity was measured by a manometric method and used as the response variable. The obtained models pointed out that the significant variables were the temperature, the value of pH, and the ratio between the unionized species of the substrates (free ammonia and free nitrous acid (FA/FNA)). There were interactions among them caused by chemical equilibriums. Total nitrogen concentration and ammonium concentration were found to be not significant in the tested range. According to the models, the optimum values of temperature, pH, and free ammonia to free nitrous acid ratio within the test ranges were, respectively, 30°C, 7.0, and 0.3. Further research at higher temperatures and lower values of pH and FA/FNA ratios would be necessary in order to find the absolute optimum conditions for the process. The obtained model can be also useful in order to develop control strategies that take into account the significant variables and their optimum ranges. A strategy to control deammonification reactors has been proposed, according to the results of the modeling.     

The Role of Leaky Boreholes in the Contamination of a Regional Confined Aquifer. A Case Study: The Campo de Cartagena Region, Spain

Poorly constructed wells (leaky or without a gravel pack) and abandoned wells can behave as conduits for the interconnection of aquifers at different depths and facilitate the transfer of contaminants between these aquifers. This is the case with Campo de Cartagena (SE Spain) where the primary land use is intensive irrigated agriculture, along with a high density of wells. The unconfined aquifer is heavily impacted by a high concentration of nitrate associated with agricultural activities. The present work provides a methodological approach to evaluate the impact of the unconfined aquifer on the water quality of the confined aquifer caused by leaky wells in high-density areas of production wells. The research approach included the use of geochemical and isotopic tools; specifically, nitrate was used as a tracer for evaluating the impact, and the code MIX_PROGRAM was used for mixing calculations. Results show an increase of the impact of the unconfined aquifer on the confined aquifer along the groundwater flow direction toward the coast, although this general pattern is controlled by local factors (pumping, intensity of agricultural practices, density of wells, and groundwater residence time).     

Lead Isotopic and Metallic Pollution Record in Tree Rings from the Copperbelt Mining�CSmelting Area, Zambia

The composition of tree rings and soils was studied at several locations affected by smelting and transportation in the vicinity of Kitwe (Copperbelt, Zambia). The contents of cobalt (Co), copper (Cu), manganese (Mn), and lead (Pb) and the ²⁰⁶Pb/²⁰⁷Pb isotope ratios in the tree rings were interpreted in relation to potential sources of contamination such as smelter production, acidification of the environment, soil composition, raw material processing, and atmospheric suspended particulate matter (SPM). The highest Co contents in the tree rings correspond to maximum ore production in the mid-1970s. Acidification through SO₂ emissions is documented in the increased Mn contents from the mid-1980s. The isotopic composition of the tree rings of the studied tree species varies in the interval 1.16?C1.34 and the youngest parts of all the studied trees exhibit a low ²⁰⁶Pb/²⁰⁷Pb ratio (<1.17). The soil isotope composition varies in the range ²⁰⁶Pb/²⁰⁷Pb?=?1.18?C1.35. The Pb isotope composition in the soils and tree rings was formed by a combination of lithogenic Pb (²⁰⁶Pb/²⁰⁷Pb????1.3), Pb in processed ores (²⁰⁶Pb/²⁰⁷Pb????1.2), and SPM (automobile) Pb (²⁰⁶Pb/²⁰⁷Pb??1.1). As the soils in the distant region have high ²⁰⁶Pb/²⁰⁷Pb ratios (>1.3) in the whole profile and simultaneously the youngest parts of the tree rings of tree species growing in this soil have a low ²⁰⁶Pb/²⁰⁷Pb ratio (<1.17), it can be assumed that the Pb in the youngest parts of the tree species is derived from absorption of SPM Pb through the bark rather than root uptake. The absence of Pb with a low ²⁰⁶Pb/²⁰⁷Pb ratio in soils in the distant area is probably affected by fires in the herbaceous and bush undergrowth and plant litter, which prevents Pb from biomass from entering the soil and mobilize it back into the atmosphere.     

Full-Scale Remediation of a Jet Fuel-Contaminated Soil: Assessment of Biodegradation, Volatilization, and Bioavailability

Here, we addressed biodegradation vs. volatilization processes, and also bioavailability limitations during biopile remediation of soil initially contaminated by more than 5,000 mg/kg of hydrocarbons. In order to select bioremediation strategies, we first conducted a biotreatability study, which included geochemical, textural, and microbiological characterization of the soil matrix. Next, we implemented five bioremediation approaches onsite in real-scale biopiles. In order to monitor hydrocarbon depletion and to distinguish between biological and non-biological processes, we analyzed chemical biomarkers by means of gas chromatography?Cmass spectrometry. In addition, a comprehensive study of soil grain size and its implications on bioavailability were studied. Furthermore, the evolution of microbial populations was also examined. Two of the strategies implemented in the biopiles (the combination of a slow-release fertilizer and a surfactant, and the use of an oleophilic fertilizer respectively) reduced the soil hydrocarbon content to under 500 mg/kg in 5 months. Additional results from this study indicate that volatilization was the predominant degradation process for light hydrocarbons (below 12 carbon atoms), whereas heavier compounds were mainly biodegraded. However, even in the most favorable situation, a residual concentration of hydrocarbons linked to the finer fraction of the soil was found.