Photodegradation of phosmet in wool wax models and on sheep wool: determination of wool wax bound phosmet by means of isotope ratio mass spectrometry

The photochemical reactions of phosmet, an organophosphorus insecticide used for plant protection and for control of ectoparasites on productive livestock, were studied in the presence of wool wax. Induced by UV light, phosmet features numerous degradation pathways as well as photoaddition reactions with lipid structure moieties. In model irradiation experiments of phosmet in mixtures of solvents (cyclohexane, cyclohexene, 2-propanol) and fatty acid methyl esters (methyl stearate, methyl oleate, 12-hydroxymethyl stearate), both adjusted to the hydroxyl and iodine values of wool wax, half-lives were determined to be approximately 7 and 16 h, respectively. Irradiation of phosmet on crude sheep wool resulted in a degradation rate of 65% after 24 h. In tracer studies with stable isotope labeled phosmet ([15N]phosmet) in commercial lanolin and on raw sheep wool, employing a sunlight simulator and natural sunlight, wool wax bound phosmet was formed. After extraction and measurement by elemental analyzer/isotope ratio mass spectrometry, delta15N values of the phosmet-free wool wax fractions were notably increased as compared to the value of natural lanolin. Calculated from the delta15N values, an average of 13.9/15.6% (sunlight simulator/natural sunlight) was bound to wool wax lipids after irradiation of thin films of commercial lanolin. In experiments with sheep wool, 13.2 and 15.4%, respectively, were detected as wax-bound.     

Old cultural traditions, in addition to land use and topography, are shaping plant diversity of grasslands in the Alps

Socio-economically motivated land use changes are a major threat for species diversity of grasslands throughout the world. Here, we comprehensively explore how plant species diversity of grasslands in the species-rich cultural landscape of the Swiss Alps depends on recent land use changes, and, neglected in previous studies, on old cultural traditions. We studied diversity in 216 grassland parcels at three altitudinal levels in 12 villages of three cultural traditions (Romanic, Germanic, and Walser). In valleys of Romanic villages more different parcel types tended to occur than in those of Germanic and Walser villages, suggesting that socio-economic differences among cultural traditions still play a role in shaping landscape diversity. Moreover, at the village level, higher man-made landscape diversity was associated with higher plant species richness. All observed changes in land use reduced the farmers’ workload. Plant species richness was lower in fertilized than in unfertilized parcels and in abandoned compared with used parcels. Grazing slightly reduced species richness compared with mowing among unfertilized parcels, while in fertilized parcels it had a positive influence. The highest species diversity was found in mown unfertilized subalpine grasslands. Nevertheless, moderate grazing of former meadows can be a valuable alternative to abandonment. We conclude that the ongoing changes in land use reduce plant species richness within parcels and at the landscape level. To preserve plant species diversity at the landscape level a high diversity of land use types has to be maintained.     

Synergistic effects of Miconazole and Polymyxin B on microbial pathogens

The therapeutic value of antibiotics depends on the susceptibility of the infecting microorganism and the pharmacological profile of the drugs. To assess the value of an antibiotic combination of polymyxin B and miconazole this study examined the in vitro synergistic potential of the two drugs on Gram-negative and Gram-positive bacteria and yeast. Antifungal and antibacterial activity was tested by minimum inhibitory concentration (MIC) of broth macrodilution and urea broth microdilution, by fluorescence microscopy and flow cytometry. Synergism was calculated using the fractional inhibitory concentration index (FICi). With Staphylococcus intermedius as target we found up to an eightfold reduction of the individual MICs when both drugs were combined. However, the FICi was 0.63 suggesting no real interaction between the two drugs. With Escherichia coli, Pseudomonas aeruginosa, and Malassezia pachydermatis as targets the antimicrobial drug combination reduced the MICs of polymyxin B and miconazole from fourfold to hundredfold resulting in FICi between 0.06 and 0.5 which defines a synergistic action. Thus, if polymyxin B and miconazole are combined their effect is greater than the sum of the effects observed with polymyxin B and miconazole independently, revealing bactericidal and fungicidal synergism. Our results indicate a strong therapeutic value for the combination of these antimicrobial agents against Gram-negative bacteria and yeast and a weaker value against Gram positive bacteria for clinical situations where these pathogens are involved.     

Feline rabies. ABCD guidelines on prevention and management

OverviewRabies virus belongs to the genus Lyssavirus, together with European bat lyssaviruses 1 and 2. In clinical practice, rabies virus is easily inactivated by detergent-based disinfectants.InfectionRabid animals are the only source of infection. Virus is shed in the saliva some days before the onset of clinical signs and transmitted through a bite or a scratch to the skin or mucous membranes. The average incubation period in cats is 2 months, but may vary from 2 weeks to several months, or even years.Disease signsAny unexplained aggressive behaviour or sudden behavioural change in cats must be considered suspicious. Two disease manifestations have been identified in cats: the furious and the dumb form. Death occurs after a clinical course of 1–10 days.DiagnosisA definitive rabies diagnosis is obtained by post-mortem laboratory investigation. However, serological tests are used for post-vaccinal control, especially in the context of international movements.Disease managementPost-exposure vaccination of cats depends on the national public health regulations, and is forbidden in many countries.Vaccination recommendationsA single rabies vaccination induces a long-lasting immunity. Kittens should be vaccinated at 12–16 weeks of age to avoid interference from maternally derived antibodies and revaccinated 1 year later. Although some vaccines protect against virulent rabies virus challenge for 3 years or more, national or local legislation may call for annual boosters.     

Feline leukaemia. ABCD guidelines on prevention and management

OverviewFeline leukaemia virus (FeLV) is a retrovirus that may induce depression of the immune system, anaemia and/or lymphoma. Over the past 25 years, the prevalence of FeLV infection has decreased considerably, thanks both to reliable tests for the identification of viraemic carriers and to effective vaccines.InfectionTransmission between cats occurs mainly through friendly contacts, but also through biting. In large groups of non-vaccinated cats, around 30–40% will develop persistent viraemia, 30–40% show transient viraemia and 20–30% seroconvert. Young kittens are especially susceptible to FeLV infection.Disease signsThe most common signs of persistent FeLV viraemia are immune suppression, anaemia and lymphoma. Less common signs are immune-mediated disease, chronic enteritis, reproductive disorders and peripheral neuropathies. Most persistently viraemic cats die within 2–3 years.DiagnosisIn low-prevalence areas there may be a risk of false-positive results; a doubtful positive test result in a healthy cat should therefore be confirmed, preferably by PCR for provirus. Asymptomatic FeLV-positive cats should be retested.Disease managementSupportive therapy and good nursing care are required. Secondary infections should be treated promptly. Cats infected with FeLV should remain indoors. Vaccination against common pathogens should be maintained. Inactivated vaccines are recommended. The virus does not survive for long outside the host.Vaccination recommendationsAll cats with an uncertain FeLV status should be tested prior to vaccination. All healthy cats at potential risk of exposure should be vaccinated against FeLV. Kittens should be vaccinated at 8–9 weeks of age, with a second vaccination at 12 weeks, followed by a booster 1 year later. The ABCD suggests that, in cats older than 3–4 years of age, a booster every 2–3 years suffices, in view of the significantly lower susceptibility of older cats.     

Regenwürmer als Bioindikatoren für Schwermetallbelastungen von Böden unter Freilandbedingungen

The use of earthworms in monitoring soil pollution by heavy metals Total heavy metal contents (HNO₃-soluble) and exchangeable fractions (Ca(NO₃)₂-soluble) of Pb, Zn and Cd were measured in soils, litter layers and earthworms (dry masses) from forest, arable and pasture sites in a transect of the main wind direction and varying distances (1.5, 5.4, 11.4, 15.6 km) to a lead smelter near Bad Ems, Germany. Additionally, cast materials of Lumbricus terrestris-individuals were collected from the surface of the pasture sites. In the observed area total soil contents of Pb and Cd exceeded the C-level and total contents of Zn the B-level of the “Netherland-list”. Heavy metal contents in soils and earthworms decreased with increasing distance to the smelter. Pb showed the best correlation. Correlation between total contents of Pb and Cd in soils and earthworms were significant (rs = 0.66; p < 0.05 and rs = 0.67; p < 0.01, respectively). The uptake of heavy metals by Lumbricus rubellus, L. terrestris and Aporrectodea caliginosa was metal specific rather than species specific with factors of accumulation being <1 (Pb), 2.7–7.6 (Zn) and 19.5–85.5 (Cd). The heavy metal contents of the observed cast materials signified the different transfer of elements from soil material via earthworm individuals to the faeces. In the cast materials the amounts of Pb were high and the amounts of Zn and Cd were low. This indicates a high accumulation rate for Zn and especially for Cd in the tissues of the observed earthworm individuals. The present data support the necessity of ecotoxicological threshold levels.     

Flavanol and bound phenolic acid contents in different barley varieties

Different barley varieties, consisting of hulled and hull-less types, of normal, waxy, and high amylose starch, as well as two-rowed and six-rowed types, were analyzed for their main proanthocyanidins and bound phenolic acids. Variations in proanthocyanidin and phenolic acid contents were studied in different barley types as well as inter-relationships between the phytochemicals and polysaccharides. The main flavanols found in the analyzed barley varieties were two dimeric as well as four trimeric forms in addition to catechin. The total amount of flavanols ranged from 325 to 527 microg/g of fresh weight of barley flour. No evident associations were found between variations in proanthocyanidin levels and different barley types. The total amount of phenolic acids ranged from 604 to 1346 microg/g of fresh weight of barley flour, with ferulic acid as the dominating acid. The amount of phenolic acids varied according to occurrence or lack of hull, with significantly higher levels in the hulled varieties.     

Biocatalytic production of dihydrocoumarin from coumarin by Saccharomyces cerevisiae

Natural dihydrocoumarin, which is of great interest in the flavor industry, was biotechnologically produced from pure coumarin or tonka bean meal with Pseudomonas orientalis, Bacillus cereus, and various Saccharomyces cerevisiae strains. Coumarin was shown to be converted to melilotic acid, which yielded dihydrocoumarin upon distillation during purification. About 1.0 g/L product was obtained from 25 g/L tonka beans with S. cerevisiae within 147 h. This dihydrocoumarin thus fulfills all of the criteria of a natural raw material and can be used as a natural flavoring in accordance with U.S. and European Union regulations.