Cyclic change in late triassic lacustrine communities

A new type of lake and shore assemblage has been found in the Late Triassic age rocks of North Carolina and Virginia (Dan River group). It includes abundant aquatic reptiles, fishes, at least seven orders of insects, crustaceans, and a diverse flora. Cyclic changes in the fauna and flora correlate with sedimentary cycles, which together reflect the repetitive development and extinction of large meromictic lakes.     

Fossil spores, pollen, and fishes from connecticut indicate early jurassic age for part of the newark group

Palynologically productive localities have been found in the United States throughout the Newark Group basins, most of which had previously been assumed to be barren. Rich palynoflorules dominated by coniferous pollen of Circulina-Classopollis type, and well-preserved fossil fishes, including possible new semionotids, have been found in the Hartford basin. Palynological data indicate that the Newark Group has considerable time-stratigraphic range: Upper Triassic for the Cumnock Formation (North Carolina), the Vinita Beds (Virginia), and the upper New Oxford Formation (Pennsylvania), Rhaeto-Liassic for the Brunswick Formation (New Jersey), Portland Formation (Connecticut and Massachusetts), and the Shuttle Meadow Formation (Connecticut).     

Development of a fast analytical method for the determination of sudan dyes in chili- and curry-containing foodstuffs by high-performance liquid chromatography-photodiode array detection

A simple and fast analytical method for the determination of sudans I, II, III, and IV in chili- and curry-containing foodstuffs is described. These dyes are extracted from the samples with acetonitrile and analyzed by high-performance liquid chromatography coupled to a photodiode array detector. The chromatographic separation is carried out on a reverse phase C18 column with an isocratic mode using a mixture of acetonitrile and water. An "in-house" validation was achieved in chili- and curry-based sauces and powdered spices. Depending on the dye, limits of detection range from 0.2 to 0.5 mg/kg in sauces and from 1.5 to 2 mg/kg in spices. Limits of quantification are between 0.4 and 1 mg/kg in sauces and between 3 and 4 mg/kg in spices. Validation data show a good repeatability and within-lab reproducibility with relative standard deviations < 15%. The overall recoveries are in the range of 51-86% in sauces and in the range of 89-100% in powdered spices depending on the dye involved. Calibration curves are linear in the 0-5 mg/kg range for sauces and in the 0-20 mg/kg range for spices. The proposed method is specific and selective, allowing the analysis of over 20 samples per working day.     

Effect of cadmium on the cytoskeleton and morphology of gill chloride cells in parr and smolt Atlantic salmon (Salmo salar)

This study documented the effect of cadmium on salmon parr and smolt gill morphology. Cadmium-induced changes in chloride cell (CC) cytoskeletal elements were investigated, as well as the modifications of CC surface area and density. In cadmium-treated parr (10 µg Cd l^-1 for 2 days), immunofluorescent light microscopy revealed the appearance of an intense actin staining located in the CC apical part. Transmission electron microscopic observations revealed a change in the organization of the microfilaments at the CC apex, with the appearance of numerous aggregates of filamentous actin. Higher cadmium concentrations (30 and 50 µg l^-1) and prolonged treatment times (7 to 14 days) did not modify such reorganisation. Microtubules were not significantly affected by similar treatments. Further, scanning electron microscopic analysis revealed that cadmium induces a significant increase of parr CC surface area as early as the second day of exposure. After 2 days, mature CC density had also increased. In smolt, a rise in CC surface area was observed, although CC density did not significantly increase.     

Water yam (Dioscorea alata L.) growth and yield as affected by the planting date: Experiment and modelling

Tubers of water yam (Dioscorea alata L.) are an important source of carbohydrates for millions of people throughout the tropics. Planting of the crop in the Caribbean and Central America is usually carried out between March and July. As water yam is very sensitive to small variations in photoperiod, changes in the planting date may greatly affect crop development and growth. The aim of this study was to assess the change in the radiation use efficiency (RUE) as a function of the planting date, and its effect on yam growth and yields. For this, we adapted the CropSyst model to simulate yam development and growth. The model was modified, calibrated and tested using two independent data sets from field experiments carried out in Guadeloupe (French Antilles) under non-limiting conditions for water and nutrients and over a wide range of planting dates and photoperiods (e.g. from 12.9 h in March to 11.3 h in October). The planting-harvest period varied from 4.4 months for the late planting dates to 9.1 months for the early planting dates. The RUE was relatively stable in the vegetative phase, increased after tuber initiation (TI) to reach a maximum value during the exponential phase of tuber growth, and then decreased towards the end of growth. The mean value of RUE increased from the early (March, 1.4 g MJ^?1) to the intermediate planting dates (July, 2.7 g MJ^?1), and then decreased for the late planting dates (October, 1.3 g MJ^?1). Maximum RUE was negatively correlated with photoperiod. This particular behaviour of RUE was induced by a source–sink interaction which was controlled by crop development and photoperiod. The model described yam development and growth satisfactorily for all the planting dates: e.g. R² > 0.92 for the correlation between modelled and measured tuber biomass. Yields varied little from the early to the intermediate planting dates because of an offset between the length of the vegetative phase, which determined leaf area, and the level of RUE after TI, which determined the capacity of the crop to fill tubers. Growth and yield drastically decreased for the late planting dates because photoperiod induced fast TI which strongly affected the leaf area. The model was a powerful tool to identify the underlying mechanisms affecting yam yields for some early planting dates, and to assess the factors involved in the high year-to-year variability currently observed in water yam yields.     

Modulations of lipid metabolism and development of the Atlantic salmon (Salmo salar) fry in response to egg-to-fry rearing conditions

In stocking program, the use of artificial incubation conditions in hatcheries from the fertilisation of eggs to the release of unfed fry could reduce their ability to adapt to the natural environment. This study evaluates the effects of three factors on the fitness and physiology of salmon fry at their emergence, the origin of water (river vs drilling), the type of support in the incubator (support matrix vs plastic sheets) and the type of incubators (Californian vs vertical trays), and compares them to a semi-natural incubation method in river. Key biological functions including nutritional and immune status were compared among experimental conditions using biometric parameters, lipid composition and gene expression analyses. Our findings demonstrated that fry incubated in vertical trays supplied with river water had no significant difference in growth and lipid composition compared to those in semi-natural incubators. Besides, fry incubated on a substrate matrix in Californian trays exhibited phenotypic characteristics closest to those incubated in river. This support matrix improved fish growth, lipid consumption and distribution compared to fry on plastic sheets. Moreover, the large amounts of several PUFAs in these fry could allow a better membrane fluidity ensuring a better adaptation to temperature variation under cold conditions. In addition, drilling water improved the survival rate compared to river water due to lower numbers of fine particles, known to be responsible for the clogging of eggs. To conclude, using a substrate combined with drilling water in artificial incubators could increase fry fitness and its adaption to wild life.