Levels of Vitellogenin in Male Japanese Medaka (Oryzias latipes) Exposed to the Chemotherapeutics: Oxytetracycline,Romet-30®, and Copper Sulfate

ABSTRACT

Japanese medaka (Oryzias latipes) were exposed to oxytetracycline and Romet-30^® at daily doses via feed of 0.06 mg, 0.11 mg, and 0.28 mg per gram body weight for 11 days, and at daily doses of 0.05 mg, 0.10 mg, and 0.15 mg per gram body weight for 5 days, respectively. In addition, fish were exposed to copper sulfate in their aquaria water at 1.85 mg/L for 1 h each day (over a span of 1 day, 7 consecutive days, or 1 day in every 3 to 5 days for a total of seven doses). Vitellogenin levels were measured in fish using a sandwich enzyme-linked immunosorbent assay (ELISA). Vitellogenin levels were not induced from exposure to either oxytetracycline or Romet-30® (P > 0.05); however, copper sulfate for 1 h on 1 day showed a decrease in vitellogenin from the control fish and other treatment groups (P = 0.007). Under these test conditions, oxytetracycline, Romet-30, and copper sulfate were not found to act in medaka as estrogenic compounds by inducing vitellogenin.     

成功人士九不同

<正>为什么有些目标你能如此成功地实现,另一些却不行?如果你弄不明白,那很正常,因为对此感到困惑的远不只你一人。其实,几十年对成功事例的研究表明,成功人士之所以能实现目标,不仅仅是因为他们的身份,更多的是因为他们的行动。以下是成功人士与众不同的九个方面。     

Total Phenolics and Antioxidant Activity of Water and Ethanolic Extracts from Distillers Dried Grains with Solubles With or Without Microwave Irradiation

The purpose of this study was to determine the efficacy of extracting phenolic compounds with antioxidant activity from distillers' dried grains with solubles (DDGS) with water, 50% aqueous ethanol, and absolute ethanol, using microwave irradiation or a water bath at various temperatures. DDGS was extracted for 15 min with each solvent while heating at 23, 50, 100, and 150°C by microwave irradiation or in a water bath at 23, 50, and 100°C. Phenolic content of extracts increased with increasing temperature to a maximum of 12.02 mg/g in DDGS extracts that were microwave irradiated in water or with 50% aqueous ethanol at 150°C. Antioxidant activity range was 1.49–6.53 μmol of Trolox equivalents/g of DDGS. Highest antioxidant activities were obtained from 50% aqueous ethanol extracts at all temperatures, and water extracts that were heated at 100 and 150°C. These data indicate that DDGS extracts with high phenolic content and antioxidant activity can be obtained from DDGS, particularly with the use of water or 50% ethanol and high temperature (100 or 150°C). This may be valuable to ethanol manufacturers, livestock producers, and food and nutraceutical companies.     

Using the ecosys mathematical model to simulate temporal variability of nitrous oxide emissions from a fertilized agricultural soil

Large temporal variability of N₂O emissions complicates calculation of emission factors (EFs) needed for N₂O inventories. To contribute towards improving these inventories, a process-based, 3-dimensional mathematical model, ecosys, was used to model N₂O emissions from a canola crop. The objective of this study was to test the hypothesis in ecosys that large temporal variability of N₂O is due to transition among alternative reduction reactions in nitrification/denitrification caused by small changes in soil water-filled pore space (WFPS) following a threshold response, which controls diffusivity (D_g) and solubility of O₂. We simulated emissions at field scale, using a 20 × 20 matrix of 36 m × 36 m grid cells rendered in ArcGIS from a digital elevation model of the fertilized agricultural field. Modelled results were compared to measured N₂O fluxes using the flux-gradient technique from a micrometeorological tower equipped with a tunable diode laser, to assess temporal N₂O variability. Grid cell simulations were performed using original, earlier and later planting and fertilizer dates, to show the influence of changing precipitation and temperature on EFs. Fertilizer application (112 kg N ha^?1), precipitation and temperature were the main factors responsible for N₂O emissions. Ecosys represented the temporal variation of N₂O emissions measured at the tower by modelling significant emissions at WFPS > 60% which reduced the oxygen diffusivity, causing a rising need for alternative electron acceptors, thus greater N₂O production via nitrification/denitrification. Small changes in WFPS above a threshold value caused comparatively large changes in N₂O flux not directly predictable from soil temperature and WFPS. In ecosys, little N₂O production occurred at WFPS < 60% because the oxygen diffusivity was large enough to meet microbial demand. Coefficients of diurnal temporal variation in N₂O fluxes were high, ranging from 25–51% (modelled) and 24–63% (measured), during emission periods (0–0.8 mg N₂O–N m² h^?1). This variation was shown to rise strongly with temperature during nitrification of N fertilizer so that EFs were affected by timing of fertilizer application. EFs almost quadrupled when fertilizer applications were delayed (average: 1.67% (fertilizer-induced emissions), causing nitrification to occur in warmer soils (18 °C), compared to earlier applications (average: 0.45%) when nitrification occurred in cooler soils (12 °C). Large temporal variation caused biases in seasonal emissions if calculated from infrequent (daily and weekly) measurements. These results show the importance of the use of models that include climate impact on N₂O, with appropriate time-steps that capture its temporal variation.     

The Year of the Rat ends—time to fight hunger!

This paper investigates the importance of ecologically based rodent management in the light of the current food crisis, and the potential effects of this approach on the position of the undernourished. Hunger and food prices are on the rise owing to shortages that can be traced to reasons such as climatic extremes, use of crops for biofuels, reduced growth in yields which lag behind population growth, reduced world stocks and lack of sufficient investment in maintaining the irrigation infrastructure. For the undernourished this is problematic as they are most vulnerable to the rise in food prices. Very often, agricultural experts focus on an increase in agricultural production to reduce food prices. It is postulated in this article that almost 280 million undernourished could additionally benefit if more attention were paid to reducing pre‐ and post‐harvest losses by rodents. Moreover, rodent‐borne diseases would decrease, diseases that can be catastrophic to the livelihoods of the poorest of the poor. Copyright © 2009 Society of Chemical Industry     

Testing and improving the effectiveness of trap crops for management of the diamondback moth Plutella xylostella (L.): a laboratory‐based study

BACKGROUND: The aim of this study was to assess white mustard (Sinapis alba L.) as a trap crop for diamondback moth [Plutella xylostella (L.)] on cauliflower [Brassica oleracea (L.) var. Lateman]. Moth behaviour on these plants and the importance of plant age and size in maintaining pest preference for trap crop plants were also investigated. RESULTS: Three times as many eggs were laid on cauliflower plants that were unprotected than on plants protected by a trap crop of white mustard. Moths remained longer on the mustard plants as a result of a doubling in the mean duration of information‐providing behaviours. Plant age had little effect on P. xylostella host preference. When plant age was constant, percentage oviposition on mustard was higher when these were larger (93%) than copresented cauliflower plants, compared with when they were smaller (68%). CONCLUSION: Trap cropping with white mustard may reduce the incidence of P. xylostella in cauliflower crops. The pest management benefits of trap crops may be maximised by using trap crop plants that are larger than the main crop plants, although relatively smaller trap crop plants may still be preferred as hosts for P. xylostella per se. Copyright © 2009 Society of Chemical Industry     

Assessment of inoculation methods to identify resistance to Fusarium crown rot in wheat

Journal of Plant Diseases and Protection - Crown rot, caused by Fusarium culmorum and Fusarium pseudograminearum, is one of the most pervasive diseases of wheat throughout the world. Fusarium...