Electrochemical sensing of total antioxidant capacity and polyphenol content in wine samples using amperometry online-coupled with microdialysis

This work describes the method for total antioxidant capacity (TAC) and/or total content of phenolics (TCP) analysis in wines using microdialysis online-coupled with amperometric detection using a carbon microfiber working electrode. The system was tested on 10 selected wine samples, and the results were compared with total reactive antioxidant potential (TRAP), oxygen radical absorbance capacity (ORAC), and chemiluminescent determination of total antioxidant capacity (CL-TAC) methods using Trolox and catechin as standards. Microdialysis online-coupled with amperometric detection gives similar results to the widely used cyclic voltammetry methodology and closely correlates with ORAC and TRAP. The problem of electrode fouling is overcome by the introduction of an electrochemical cleaning step (1-2 min at the potential of 0 V vs Ag/AgCl). Such a procedure is sufficient to fully regenerate the electrode response for both red and white wine samples as well as catechin/Trolox standards. The appropriate size of microdialysis probes enables easy automation of the electrochemical TAC/TCP measurement using 96-well microtitration plates.     

Prediction of the water sorption isotherm in air dry soils

Within this work we present a revised pedotransfer function (PTF) that predicts water sorption isotherms for dry soils based on the clay content of the soils. When the water sorption isotherm is plotted as a water retention curve (log water potential plotted against the water content) it typically results in a log linear function as described by Campbell and Shiozawa (1992). The linear function is defined by its slope and a fixed endpoint at zero water content. The reciprocal of the slope shows a strong correlation with the clay fraction. For the calibration of a PTF we measured water sorption data for 18 soils with clay contents from 2% to 61%. The final predictions of the water sorption isotherms from the clay mass fraction were very good if the clay content was higher than 7%. The use of a revised theoretical endpoint at the dry end of the WRC did improve the prediction as compared to the endpoint that has been used in the literature before. In addition Literature data for 22 soils and 3 pure clay minerals were used for validation. The good performance of the PTF only occurred if the clay fraction was dominated by 2:1 clay minerals. The water retention isotherm of soils rich in the 1:1 clay mineral kaolinite could not be predicted by this approach; the actual water content was strongly over-predicted and the water retention curve did not follow a log linear relationship.     

Mortality at wind-farms is positively related to large-scale distribution and aggregation in griffon vultures

Wind-farms have negative impacts on the environment, mainly through habitat destruction and bird mortality, making it urgent to design predictive tools to use in landscape planning. A frequent assumption of wind-farm assessment studies is that bird distribution and abundance and bird mortality through collision with turbines are closely related. However, previous results are contradictory and question the usefulness of these variables to select safer wind-farm locations. We focused on a species highly vulnerable to collision at wind-farms, the griffon vulture, to test whether mortality at turbines was related to the relative position of turbines within the vulture population. We used the location of all turbines on 34 wind-farms in southern Spain, details on 342 griffon vultures found dead, and the location and size of breeding colonies and roost sites of the species during the breeding and non-breeding seasons, respectively. Using variables that describe the large-scale distribution and aggregation of vultures, we found that year-round mortality at turbines increased when they were located in highly populated areas, a result that can be translated into management guidelines to plan wind-farm locations.Bird abundances can help to guide wind-farm plans at large scales. Current protocols of counting birds at specific points during particular periods of time have low predictive power. However, other more integrative cues such as the spatial distribution and aggregation of some vulnerable species should be used as criteria for large-scale environmental planning. Local inspection of the relationship between mortality at existing turbines and their relative position within the spatial distribution of bird populations can guide managers in planning future wind-farms and in managing currently operating developments.     

Water and thermal regime of extensive green roof test beds planted with sedum cuttings and sedum carpets

Journal of Soils and Sediments - Implementation of green roofs could help to reduce rapid runoff and help cities to mitigate heat islands. The aim of the study is to assess the water and...     

Pathology of experimental SARS coronavirus infection in cats and ferrets

The pathology of severe acute respiratory syndrome-coronavirus (SARS-CoV) infection in cats and ferrets is poorly described, and the distribution of angiotensin-converting enzyme 2 (ACE2), a receptor for SARS-CoV, in the respiratory tracts of these species is unknown. We observed SARS-CoV antigen expression and lesions in the respiratory tracts of 4 cats and 4 ferrets at 4 days postinoculation and ACE2 expression in the respiratory tracts of 3 cats and 3 ferrets without infection. All infected cats and ferrets had diffuse alveolar damage associated with SARS-CoV antigen expression. A novel SARS-CoV-associated lesion was tracheo-bronchoadenitis in cats. SARS-CoV antigen expression occurred mainly in type I and II pneumocytes and serous cells of tracheo-bronchial submucosal glands of cats and in type II pneumocytes of ferrets. ACE2 expression occurred mainly in type I and II pneumocytes, tracheo-bronchial goblet cells, serous epithelial cells of tracheo-bronchial submucosal glands in cats, and type II pneumocytes and serous epithelial cells of tracheo-bronchial submucosal glands in ferrets. In conclusion, the pathology of SARS-CoV infection in cats and ferrets resembles that in humans except that syncytia and hyaline membranes were not observed. The identification of tracheo-bronchoadenitis in cats has potential implications for SARS pathogenesis and SARS-CoV excretion. Finally, these results show the importance of ACE2 expression for SARS-CoV infection in vivo: whereas ACE2 expression in type I and II pneumocytes in cats corresponded to SARS-CoV antigen expression in both cell types, expression of both ACE2 and SARS-CoV antigen in ferrets was limited mainly to type II pneumocytes.     

Quantitative analysis of the 2002 phocine distemper epidemic in the Netherlands

Phocine distemper virus (PDV) caused thousands of deaths among harbor seals (Phoca vitulina) from the North Sea in 1988 and 2002. To examine the effects of different factors on the pathology of phocine distemper, we performed necropsies and laboratory analyses on 369 harbor seals that stranded along the Dutch coast during the 2002 PDV epidemic. Diagnostic tests for morbillivirus infection indicated a differential temporal presence of morbillivirus in lung and brain. Seals of 3 years or older were significantly more often IgG positive than younger seals. The most frequent lesions in PDV cases were bronchopneumonia, broncho-interstitial pneumonia, and interstitial emphysema. Extra-thoracic emphysema was rare in <1-year-olds compared with older seals, even though severe pneumonia was more common. PDV cases generally had empty stomachs and less blubber than by-caught seals from before the epidemic. In PDV cases involving older animals, lung, kidney, and adrenal weights were significantly increased. Bordetella bronchiseptica was isolated from lungs in two thirds of the PDV cases examined. Our results indicate that brain should be included among the tissues tested for PDV by RT-PCR; that either phocine distemper has a longer duration in older seals or that there are age-related differences in immunity and organ development; that dehydration could play a role in the course and outcome of phocine distemper; and that bacterial coinfections in lungs are more frequent in PDV cases than gross lesions suggest. These results illustrate how quantitative analysis of pathology data from such epidemics can improve understanding of the causative disease.     

Activatable Shiga toxin 2d (Stx2d) in STEC strains isolated from cattle and sheep at slaughter

Shiga toxin producing Escherichia coli (STEC) harbouring the stx(2d-activatable) gene and expressing the mucus- and elastase-activatable phenotype have been associated with severe outcomes of human disease. However, there is limited data available on the occurrence of such strains in livestock reservoirs. In this study, we analyzed 11 STEC strains isolated from healthy cattle and sheep at slaughter that were originally detected to contain the stx(2c) allele, for the presence of the stx(2d-activatable) genotype. Ten of the eleven strains displayed the stx(2d-activatable) genotype as determine by PstI restriction fragment length polymorphism (RFLP) of 890-bp fragments of their stx genes. However, only in 6 of the 10 strains whose stx genes were sequenced, the presence of stx(2d-activatable) could be confirmed based on the predicted amino acid sequence of their StxA subunits; the remaining four strains contained Stx2c A subunit. Five of the six strains which contained stx(2d-activatable) displayed the activatable phenotype on Vero cells. Genes for adhesins such as the outer membrane protein intimin (eae), which is essential for the intimate attachment and the formation of attaching-and-effacing lesions on intestinal epithelial cells, or the STEC autoagglutinating adhesin (saa), potentially important in eae-negative STEC, were not detected. Moreover, all the strains tested negative for EHEC-hlyA encoding enterohaemorrhagic E. coli (EHEC) hemolysin. To our knowledge, this is the first study that reports the presence of STEC harbouring stx(2d-activatable) and producing the activatable Stx2d in fecal samples of sheep. Therefore both cattle and sheep are reservoirs of such strains and potential sources of human infections. This is of particular importance, because in contrast to other eae-negative STEC, strains producing Stx2d(activatable) may cause severe diseases such as bloody diarrhoea and haemolytic uremic syndrome in humans.     

Serologic evidence of West Nile virus and Usutu virus infections in Eurasian coots in the Netherlands

West Nile virus (WNV) and Usutu virus (USUV) are arboviruses that are maintained in enzootic transmission cycles between mosquitoes and birds and are occasionally transmitted to mammals. As arboviruses are currently expanding their geographic range and emerging in often unpredictable locations, surveillance is considered an important element of preparedness. To determine whether sera collected from resident and migratory birds in the Netherlands as part of avian influenza surveillance would also represent an effective source for proactive arbovirus surveillance, a random selection of such sera was screened for WNV antibodies using a commercial ELISA. In addition, sera of jackdaws and carrion crows captured for previous experimental infection studies were added to the selection. Of the 265 screened serum samples, 27 were found to be WNV–antibody‐positive, and subsequent cross‐neutralization experiments using WNV and USUV confirmed that five serum samples were positive for only WNV‐neutralizing antibodies and seven for only USUV. The positive birds consisted of four Eurasian coots (Fulica atra) and one carrion crow (Corvus corone) for WNV, of which the latter may suggest local presence of the virus, and only Eurasian coots for USUV. As a result, the screening of a small selection of serum samples originally collected for avian influenza surveillance demonstrated a seroprevalence of 1.6% for WNV and 2.8% for USUV, suggesting that this sustained infrastructure could serve as a useful source for future surveillance of arboviruses such as WNV and USUV in the Netherlands.