Chronic toxicity of fenoxycarb to the midge Chironomus riparius after exposure in sediments of different composition

Background, aim, and scope  

Fenoxycarb is an insect growth regulator widely used to control a variety of pests. As a juvenile hormone analogue, it interacts with the natural hormones involved in insect development, inhibiting metamorphosis to the adult stage. Adverse effects of fenoxycarb on non-target organisms have been repeatedly observed and its rapid dissipation from water to the organic fraction of the sediment is known. The aim of this work was to investigate the impact of fenoxycarb on the development of sediment-dwelling larvae of the midge Chironomus riparius after exposure to spiked sediment.     

Excretion of Leptospira interrogans serovar hardjo following calving or abortion

Leptospira interrogans serovar hardjo was demonstrated in the vaginal discharges of 12 experimentally infected heifers for up to eight days after abortion or calving. Organisms were recovered from the oviducts of heifers examined at slaughter eight to 22 days after calving or 32 to 91 days after infection. They were also recovered from the uteri of four heifers eight to 22 days after calving.     

Germination of <Emphasis Type="Italic">Plasmodiophora brassicae</Emphasis> resting spores stimulated by a non-host plant

Plant-induced germination of Plasmodiophora brassicae resting spores was studied in a laboratory experiment. Spore reaction was analysed in nutrient solution with exudates from growing roots of different plant species – one host plant (Brassica rapa var. pekinensis) and four non-host plants (Lolium perenne, Allium porrum, Secale cereale and Trifolium pratense) – and in controls with distilled water and nutrient solution. It was found that root exudates from L. perenne stimulated spore germination more than exudates from the other plants, including those from the host plant. The effect could not be explained by differences in the nutritional composition of the solutions due to differential uptake of the plant species, or by differences in root activity, measured as exudation of soluble sugars. This is the first time such a separation of factors has been done in analysing the influence of plants on P. brassicae germination. Although stimulation of P. brassicae resting spore germination is not restricted to the presence of host plants, it seems to vary depending on the plant species.     

Identification of a Pro-Angiogenic Potential and Cellular Uptake Mechanism of a LMW Highly Sulfated Fraction of Fucoidan from Ascophyllum nodosum

Herein we investigate the structure/function relationships of fucoidans from Ascophyllum nodosum to analyze their pro-angiogenic effect and cellular uptake in native and glycosaminoglycan-free (GAG-free) human endothelial cells (HUVECs). Fucoidans are marine sulfated polysaccharides, which act as glycosaminoglycans mimetics. We hypothesized that the size and sulfation rate of fucoidans influence their ability to induce pro-angiogenic processes independently of GAGs. We collected two fractions of fucoidans, Low and Medium Molecular Weight Fucoidan (LMWF and MMWF, respectively) by size exclusion chromatography and characterized their composition (sulfate, fucose and uronic acid) by colorimetric measurement and Raman and FT-IR spectroscopy. The high affinities of fractionated fucoidans to heparin binding proteins were confirmed by Surface Plasmon Resonance. We evidenced that LMWF has a higher pro-angiogenic (2D-angiogenesis on Matrigel) and pro-migratory (Boyden chamber) potential on HUVECs, compared to MMWF. Interestingly, in a GAG-free HUVECs model, LMWF kept a pro-angiogenic potential. Finally, to evaluate the association of LMWF-induced biological effects and its cellular uptake, we analyzed by confocal microscopy the GAGs involvement in the internalization of a fluorescent LMWF. The fluorescent LMWF was mainly internalized through HUVEC clathrin-dependent endocytosis in which GAGs were partially involved. In conclusion, a better characterization of the relationships between the fucoidan structure and its pro-angiogenic potential in GAG-free endothelial cells was required to identify an adapted fucoidan to enhance vascular repair in ischemia.     

Alkali combined extrusion pretreatment of corn stover to enhance enzyme saccharification

Because of good adaptability, high throughput and continuous feature, twin-screw extrusion has been shown to be a promising pretreatment method for biomass to open the cell wall at the microscopic scale. This greatly increases the specific surface area for enzyme adsorption regardless of crystallinity. The objective of this study was to investigate the effectiveness of alkali-assisted extrusion for improving corn stover digestability. The glucose and xylose sugar yields for combined process were 86.8% and 50.5%, respectively, at an alkali loading of 0.04 g/g dry biomass, a screw speed of 80 rpm, temperature of 140 °C and washed with water. The average residence time for extrusion is 27 min for 100 g corn stover. These yields were 3.9 and 13.3 times higher than their untreated counterparters. The crystallinity index was not related with hydrolysis yields. Congo red dye adsorption indicated that alkali-assisted extrusion produced significantly more pores at the meso and large scales compared to untreated material, which significantly improved the sugar yields.     

Relationship of phenotypic structures and allelochemical compounds of okra (Abelmoschus spp.) to resistance against Aphis gossypii Glover

The cotton aphid (Aphis gossypii) is one of the major pests of okra. Eleven okra varieties collected from farmers' fields in Cameroon and four aphid-resistant accessions from The World Vegetable Center (AVRDC, Asian Vegetable Research and Development Center) were evaluated from October 2012 to March 2013, and another seven aphid-resistant accessions from AVRDC were evaluated from March to July 2013 at AVRDC's Nkolbisson station, Yaoundé, Cameroon. Accessions selected from these trials were screened in an advanced confirmatory screening in autumn (October–December) 2013 in Shanhua, Taiwan. Results showed that none of the farmers' landraces were resistant to aphids. Two accessions (VI041210 and VI033824) with the lowest aphid populations had the highest trichome density. Analysis of various phytochemicals in selected okra accessions revealed that higher nitrogen and potassium levels made the okra accessions susceptible to aphids during the reproductive stage of the plants. Similarly, the total phenol content was lower in moderately resistant accessions during their reproductive stage. Aphid feeding induced an increase in phenols, and to a lesser extent, tannins. Accessions VI041210 and VI033824 could be incorporated into an integrated pest management strategy to enhance productivity of okra.     

Crop Disease Review Maize

Variability in the insecticidal effects of botanical preparations has been one of the major obstacles in the application of this type of insecticide. Understanding of the variability may help to improve formulations of the preparations and develop more practical strategies for field applications. Here we report the varying effects of two lots of the same commercial neem formulation, Neemix^® 4.5, on the diamondback moth, Plutella xylostella L. We found that one lot had stronger adverse effect on the development and survival of P. xylostella larvae but little repellent effect on the adults, whereas, the other lot had a weaker effect on the larvae but a substantial repellent effect on the adults.     

Temporary Turnout for Free Exercise in Groups: Effects on the Behavior of Competition Horses Housed in Single Stalls

In Germany, most competition horses are housed in single stalls and free exercise is not permitted in many cases. The reason for not allowing free exercise is mostly the risk of injury. Additionally, opinions exist that the horses’ demand for exercise is fulfilled by training and that the horses’ willingness to perform is negatively influenced by free exercise. In the present study, three turnout practices were investigated with regard to their effect on the behavior of four horses: daily training without free exercise (no turnout), 2-hour turnout (for free exercise) before training, and 2-hour turnout after training. The aim of this study was to determine any differences in the horses’ behavior between the three treatments. The horses’ behavior in the stable was observed through video recordings. The behavior during turnout was observed directly and during training was evaluated by the riders with the aid of a questionnaire. Additionally, the distance covered during turnout was measured by Global Positioning System devices. The behavior within the stall was more restless in the treatment without turnout—which became apparent in significantly more frequent changes between behaviors as compared with the treatments with turnout. The results of Global Positioning System measurement during turnout showed a significantly shorter distance covered when horses were trained before they were turned out compared with turnout before training. If the horses were turned out after training, they also showed less trotting and cantering and more dozing. The horses’ willingness to perform was not significantly different between the three treatments.     

Comparison of two assays, a faecal egg count reduction test (FECRT) and a coproantigen reduction test (CRT), for the diagnosis of resistance to triclabendazole in Fasciola hepatica in sheep

A sheep trial was performed to evaluate two diagnostic assays, a faecal egg count reduction test (FECRT) and a coproantigen reduction test (CRT), for the diagnosis of resistance of Fasciola hepatica to triclabendazole (TCBZ). The FECRT defines successful TCBZ treatment as a 95% or greater reduction in fluke faecal egg counts (FECs) at 14 days post-treatment (dpt). The CRT defines effective TCBZ treatment as faeces negative for Fasciola coproantigens at 14dpt, as measured by the commercial BIO K201 coproantigen ELISA (Bio-X Diagnostics, Jemelle, Belgium). Forty-nine indoor-reared sheep were split into four trial groups and each sheep was infected with 200 metacercariae of 1 of 4 F. hepatica isolates, previously described as susceptible (Cullompton and Fairhurst) and resistant (Leon and Oberon) to TCBZ action, respectively. TCBZ treatment was administered at 12 weeks post-infection (wpi) to one sub-group in each infected sheep group, and these sheep were culled at 4 weeks post-treatment (wpt). Untreated sheep sub-groups, were culled at a parallel time-point, that is, at 16wpi. Necropsy was performed to confirm treatment efficacy. Individual faecal samples were collected twice-weekly throughout the trial period, sub-sampled and examined by a standardised egg sedimentation protocol and by the BIO K201 ELISA. Results supported the use of both the FECRT and the CRT for the diagnosis of resistance of F. hepatica to TCBZ. In addition, the study confirmed the TCBZ susceptibility of the Cullompton and Fairhurst F. hepatica isolates and the TCBZ resistance of the Oberon F. hepatica isolate. However, the Leon F. hepatica isolate was found to be susceptible, rather than resistant, to TCBZ action.