Photolysis experiments on phosmet, an organophosphorus insecticide

The organophosphorus insecticide phosmet is used in plant protection as well as against parasites on animals. Phosmet showed numerous photoinduced reaction pathways, which first were studied in the presence of model environments for animal fur lipids (e.g., wool wax). The model solvents for saturated and unsaturated lipids were cyclohexane and cyclohexene, whereas methanol and 2-propanol were used as models for primary and secondary alcohol moieties of lipids. The measured degradation rates over an irradiation period of 7 h in all solvents used were very similar (49-55%). The obtained photoproducts generally included phthalimide, N-hydroxymethylphthalimide, and N-methoxymethylphthalimide. Furthermore, depending on the solvent used, additional degradation products were detectable as N-isopropoxy- and N-methylphthalimide in the presence of 2-propanol and cyclohexene, respectively. However, in the presence of cyclohexene, despite the similar turnover, distinctly lower concentrations of photoproducts were found, indicating further still unknown degradation pathways. Irradiations in methanol with increasing percentages of water led to higher degradation rates; however, the products were found to be the same. Irradiation experiments with pure phosmet on silica TLC plates and glass surfaces resulted in degradation rates of 19 and 32%, respectively, after 6 h. The results obtained clearly demonstrate for the first time that the photoinduced degradation of phosmet is strongly dependent on the chemical environment, affecting less the turnover than the photoproducts formed. The results additionally demonstrate the need to investigate the degradation behavior of phosmet on wool and in the presence of wool wax.     

Photodegradation chemistry of the insecticide phosmet in lipid models and in the presence of wool wax, employing a 15N-labeled compound

The organophosphorus insecticide phosmet is commonly used for plant protection as well as against pests on animals. Phosmet features numerous degradation pathways induced by UV irradiation. In this study, we focused on the reaction possibilities of phosmet in the presence of lipophilic substances with olefinic structure elements, as they are frequently found in animal fur lipids, especially in wool wax. In the first step, simple models were employed to characterize the structural types of formed photoaddition products. On irradiation in the presence of cyclohexene, three photoaddition products were identified, a (4pi + 2pi) cycloaddition product of phosmet and cyclohexene and two diastereoisomer carbinols. Likewise, in more sophisticated models employing fatty acid methyl esters for irradiation experiments, phosmet was readily photodegraded. In the presence of methyl oleate, also 1:1 photoaddition products could easily be identified by means of liquid chromatography-mass spectrometry, using a stable isotope-labeled phosmet (15N-phosmet, 50 at. %) for the photolysis experiments. To converge from models to the more complex natural environment of animal skin lipids, irradiation experiments of phosmet in the presence of wool wax were performed. After 24 h of irradiation, only a remnant of 1.4% of the initial phosmet was detectable. Phosmet-oxon was detected in concentrations up to 27.3 mol %.     

Persistence and conservation of a consumer-resource metapopulation with local overexploitation of resources

The monophagous flightless weevil Hadramphus spinipennis causes the frequent local extinction of its host plant Aciphylla dieffenbachii through overexploitation. Both species are endemic and restricted to the Chatham Islands group (New Zealand). The weevil is classified as endangered and the plant as a threatened species. As this herbivore-plant system is locally unstable long-term persistence only appears possible via a metapopulation structure in which subpopulations are connected by dispersal. This paper investigates this hypothesis using a spatially explicit model of a consumer population whose resource is patchily distributed. The parameters are adapted to the H. spinipennis-A. dieffenbachii system. Our model includes local population dynamics and dispersal of the consumer, the destruction of host plant patches due to foraging and their regeneration. The results show that the key factor for long-term persistence is the short-range dispersal of the consumer with high mortality during dispersal. Only this highly inefficient dispersal prevents the synchronisation of local dynamics while ensuring sufficient colonisation of regenerated patches. We also show that although synchronisation through spatially correlated environmental fluctuations may be critical for long-term persistence, it cannot replace the strong effects of dispersal. Thus, in a consumer-resource metapopulation with deterministic local extinction, the strength and spatial scale of consumer dispersal in relation to the spatial and temporal scales of the resource patch dynamics (patch destruction and regeneration, number, size and distance of patches) play a vital role for long-term persistence. The consequence for conservation management is that such metapopulations could in fact profit rather than suffer from decreasing connectivity of resource patches.     

Identification and quantification of caffeoylquinic acids and flavonoids from artichoke (Cynara scolymus L.) heads, juice, and pomace by HPLC-DAD-ESI/MS(n)

A method for the identification and quantification of phenolic compounds from artichoke (Cynara scolymus L.) heads, juice, and pomace by HPLC with diode array and mass spectrometric detection was developed. Among the 22 major compounds, 11 caffeoylquinic acids and 8 flavonoids were detected. Quantification of individual compounds was carried out by external calibration. Apigenin 7-O-glucuronide was found to be the major flavonoid in all samples investigated. 1,5-Di-O-caffeoylquinic acid represented the major hydroxycinnamic acid, with 3890 mg/kg in artichoke heads and 3269 mg/kg in the pomace, whereas in the juice 1,3-di-O-caffeoylquinic acid (cynarin) was predominant, due to the isomerization during processing. Total phenolic contents of approximately 12 g/kg on a dry matter basis revealed that artichoke pomace is a promising source of phenolic compounds that might be recovered and used as natural antioxidants or functional food ingredients.     

Intussusception following methiocarb toxicity in three dogs

Objective: To report intussusception as a complication of methiocarb toxicity in dogs and discuss possible risk factors. Series summary: Intestinal intussusception was diagnosed from 24 hours to 18 days following symptomatic treatment of methiocarb toxicity in three dogs. All cases had persistent clinical signs of methiocarb toxicity despite initial treatment and attempts to eliminate residual toxin. Cases 1 and 3 recovered uneventfully following supportive care, enterectomy of the affected bowel and end‐to‐end anastamosis. All dogs were <8 months of age. New information provided: Details of three cases of methiocarb toxicity that later developed intussusception and possible risk factors in these cases.     

Kettle holes reflect the biogeochemical characteristics of their catchment area and the intensity of the element-specific input

Journal of Soils and Sediments - Kettle holes are small inland water bodies known to be dominated by terrigenous material; however, the processes and structures that drive the enrichment and...     

Prevalence of specific IgG-antibodies against Toxoplasma gondii in domestic turkeys determined by kinetic ELISA based on recombinant GRA7 and GRA8

The protozoan parasite Toxoplasma (T.) gondii is one of the most common zoonotic infectious agents worldwide. Besides its sexual reproduction in cats, T. gondii can also infect a wide spectrum of other warm-blooded animals. These include animals used for human consumption such as pigs or chickens. Nevertheless, the role of turkeys for the epidemiology of T. gondii infections has not been studied thoroughly. We have established a kinetic ELISA (KELA) for the detection of T. gondii-specific IgG antibodies in turkey serum samples. The test is based on the recombinant dense granule antigens GRA7 and GRA8. These proteins were used as an antigen mixture at a concentration of 0.13 μg per well. The overall sensitivity of the assay was between 92.6% and 100% and the specificity ranged from 78.1% to 100%, depending on the method used to calculate these parameters. Using this KELA we examined 1913 turkey serum samples from 14 turkey farms from different areas of Germany. From these sera, 387 produced a signal in the KELA, corresponding to a true seroprevalence of up to 20.2%. The seropositivity rate in individual fattening cycles at individual farms ranged from 0.0% to 77.1%, whereas the rates were highly variable within the individual farms and individual fattening cycles. Consequently, conditions of animal husbandry could not be associated with particular seroprevalence rates. Although seropositivity cannot be linked directly to infectious tissue cysts in the muscle tissue of commercially produced turkey meat, we state that there is a potential risk of being infected by consuming turkey meat products that were not heat treated.     

Two outbreaks of virulent systemic feline calicivirus infection in cats in Germany

Over the last years, several outbreaks of virulent systemic feline calicivirus (VS-FCV) infection have been described in the USA and several European countries. The paper describes two outbreaks of VS-FCV infection in cats in Germany. Data concerning clinical, laboratory, and histopathological features ofVS-FCV infection were collected from two outbreaks affecting 55 and 4 cats, respectively. Presence of feline calicivirus was confirmed by PCR followed by sequencing of the PCR-products. Clinical signs were variable, including severe upper respiratory tract infection, dyspnoea, oral and footpad ulceration, facial oedema, enteritis, pneumonia, bleeding disorder, high fever, and icterus. Both outbreaks were characterized by a high mortality rate.The present report describes the first documented outbreaks of VS-FCV infection in cats in Germany. Clinical and histopathological features are comparable to outbreaks described in the USA and Europe. However, phylogenetic analysis of the virus genome suggests that virus strains involved in these outbreaks were different from each other and from virulent strains isolated before, confirming the known genetic variability of FCV.     

Protein insertion into the mitochondrial inner membrane by a twin-pore translocase

The mitochondrial inner membrane imports numerous proteins that span it multiple times using the membrane potential Deltapsi as the only external energy source. We purified the protein insertion complex (TIM22 complex), a twin-pore translocase that mediated the insertion of precursor proteins in a three-step process. After the precursor is tethered to the translocase without losing energy from the Deltapsi, two energy-requiring steps were needed. First, Deltapsi acted on the precursor protein and promoted its docking in the translocase complex. Then, Deltapsi and an internal signal peptide together induced rapid gating transitions in one pore and closing of the other pore and drove membrane insertion to completion. Thus, protein insertion was driven by the coordinated action of a twin-pore complex in two voltage-dependent steps.