A molecular graphics study of factors influencing herbicidal activity of oximes of 3-acyl-tetrahydro-2H-pyran-2,4-diones

Structure-activity relationships in oximes of a series of sixteen 3-acyltetrahydro-2H-pyran-2,4-diones, exhibiting a variety of pre- and postemergent herbicidal activities, have been studied by means of computer graphics methods. The most active compounds are potent grass-killers. This graminicidal activity appears to depend strongly on the size and shape of the substituent at the 6-position of the pyran. The activity correlates with both molar refractivity and fit to a hypothetical ‘receptor’ probably the active site of acetyl coenzyme A carboxylase. The herbicide sethoxydim and the pyrandione herbicides appear to mimic the transition state of the reaction catalyzed by acetyl-CoA carboxylase. The study has yielded a receptor model which defines clearly the three-dimensional binding reguirements of the pyran ring and the substituents at the 6 position. It is not capable of providing information on the structural requirements of the 3-acyl moiety. The model is capable of discriminating between active and inactive herbicidal compounds and provides a basis for the design of new herbicidal compounds with enhanced graminicidal activity.     

Initial deposits and persistence of azadirachtin in fir and oak foliage after spray application of ‘Margosan-O’® formulation

Foliar deposits and persistence of azadirachtin were investigated after spraying ‘Margosan-O’® formulation at three dosage and volume rates on to balsam fir and oak seedlings in a laboratory chamber. Droplet-size spectra and deposits were assessed using artificial samplers, and foliar residues were measured by high-performance liquid chromatography (HPLC) at different intervals of time after treatment. Disappearance of azadirachtin from both types of foliage was rapid, and the DT₅₀ (the time required for 50% of the initial concentration to disappear) values ranged from 17 to 22 h. The initial azadirachtin concentrations varied widely from 4 to 96 μg g^?1 (fresh weight), but the rate constants 0.0311 to 0.0414, were not significantly different. The data thus indicated a poor relationship between initial concentrations and the rate of loss. The influence of spray droplet size and cuticular wax content of foliage on persistence of azadirachtin was investigated using both foliar types, and glass microscope slides without and with the foliar wax coating. Neither the type of surface nor the droplet size influenced the persistence. The rate of azadirachtin loss from the glass slides was faster than from both types of foliage, and was unaffected by the presence of wax coating. The fir foliage had higher cuticular wax content than the oak foliage, but the persistance of azadirachtin was similar in both foliar types.     

Effects of L‐methionine on performance,gut morphology and antioxidant status in gut and liver of piglets in relation to DL‐methionine

This study investigated the hypothesis that dietary supplementation of L‐methionine (L‐Met) in weaned piglets in relation to DL‐methionine (DL‐Met) results in a higher antioxidant status and lower need for antioxidant enzyme activation in intestinal epithelium and body tissues, and improves gut morphology and gut barrier function as well as performance. A total of 99 early‐weaned 21‐day old piglets were allotted to six groups and fed a semi‐synthetic wheat–barley‐based basal diet supplemented with 0.067%, 0.107% and 0.147% of either DL‐Met (MetAmino; Evonik, Hanau, Germany) or L‐Met (L‐Met100; CJ Europe, Schwalbach am Taunus, Germany) to reach dietary Met concentrations of 0.16%, 0.20% and 0.24%, of which the latter met the requirements for maintenance and growth based on a pre‐experiment. Feed intake and body weights were recorded weekly, and samples of plasma, liver and duodenum and jejunum mucosa were collected after 3 weeks at slaughter. Plasma concentrations of L‐Met were similar, and those of D‐Met and total Met were higher in piglets fed DL‐Met in relation to those fed L‐Met. Feed intake, daily gains and feed:gain ratio, and the relative bio‐efficacy based on gains and feed:gain ratio were similar for both groups. Likewise, villi length, crypt depth, the villi length:crypt depth ratio in duodenum and jejunum and gene expression of tight junction proteins in the jejunum did not differ. Concentrations of antioxidants like glutathione and tocopherol, the total antioxidant capacity, the mRNA abundance or activity of antioxidant enzymes like superoxide dismutase and glutathione peroxidase, concentrations of thiobarbituric acid reactive substances, markers for oxidative damage of lipids and the expression of inflammatory genes were similar in liver and jejunum mucosa. These data indicate that the effects of L‐Met and DL‐Met supplementation are comparable considering both piglet performance and parameters of gut health and function like gut morphology and the intestinal antioxidant status.     

Intermittent Aeration for In-vessel Composting Of Crab Processing Waste

A crab processing waste/wood shaving mixture was composted in-vessel with four intermittent aeration strategies. The composting process was monitored to assess the efficacy of the aeration methods. Temperature, moisture content and volatile solids of the compost were monitored along with the interstitial oxygen concentration. There was no significant difference in temperature profiles between constant frequency aeration and temperature feedback controlled aeration methods. An increased frequency of aeration resulted in significantly more drying than the less frequent aeration using the same total air volume. Results indicated that air volume could be reduced after the first five days of composting, and the in-vessel composting retention time could be reduced to 15 to 17 days for odor and vermin/vector problems prevention.     

Intake of specific flavonoids and risk of acute myocardial infarction in Italy

OBJECTIVE: As intake of flavonoids has been associated with reduced risk of coronary heart disease but data on the relation with specific classes of flavonoids are scarce, we assessed the relation between dietary intake of specific classes of flavonoids and the risk of acute myocardial infarction (AMI) in an Italian population.DESIGN: Case-control study. Dietary information was collected by interviewers on a questionnaire tested for validity and reproducibility. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were obtained by multiple logistic regression models including terms for energy and alcohol intake, as well as sociodemographic factors, tobacco and other major recognised risk factors for AMI.SETTING: Milan, Italy, between 1995 and 2003.SUBJECTS: Cases were 760 patients, below age 79 years, with a first episode of non-fatal AMI, and controls were 682 patients admitted to hospital for acute conditions unrelated to diet.RESULTS: A reduced risk of AMI was found for increasing intake of anthocyanidins (OR=0.45, 95% CI 0.26-0.78 for the highest vs. the lowest quintile, Ptrend=0.003) and flavonols (OR=0.65, 95% CI 0.41-1.02, Ptrend=0.02). A tendency towards reduced risks, although not significant, was observed for flavan-3-ols (OR=0.73, 95% CI 0.48-1.10) and total flavonoids (OR=0.74, 95% CI 0.49-1.14). No meaningful heterogeneity was found between the sexes. No association emerged for other flavonoids, including isoflavones, flavanones and flavones.CONCLUSIONS: High intake of anthocyanidins reduced the risk of AMI even after allowance for alcohol, fruit and vegetables, supporting a real inverse association between this class of flavonoids and AMI risk.     

First report of multiresistant, mecA-positive Staphylococcus intermedius in Europe: 12 cases from a veterinary dermatology referral clinic in Germany

Resistance to cephalosporins and/or fluoroquinolones by Staphylococcus intermedius has remained low in Europe, with effective drugs generally available for systemic therapy in pets. However, multiresistant, mecA-positive S. intermedius isolated from dogs and cats is now emerging in Europe. Twelve S. intermedius isolates, highly resistant to at least five antimicrobial classes, were isolated from skin and ear infections in 11 dogs and a cat. The 12 isolates represented 23% of all S. intermedius submissions from one veterinary dermatology referral clinic in northern Germany to veterinary diagnostic laboratories during an 18-month period and resistance included cefalexin, methicillin and enrofloxacin. The animals had been referred to the clinic with recurrent superficial pyoderma, deep pyoderma, pododermatitis or chronic otitis, all unresponsive to systemic beta-lactam-antibiotics or fluoroquinolones. Infection resolved in 10 dogs and the cat on a combination of antimicrobial treatment and correction of underlying causes. Four dogs and a cat required systemic and topical therapy; in six dogs topical antimicrobial therapy alone was successful. Phenotypic and genotypic characteristics of the S. intermedius isolates were determined; species identification was confirmed by polymerase chain detection of thermonuclease genes (nuc) and the presence and expression of the gene conferring resistance to all beta-lactam antibiotics (mecA) were demonstrated in all; based on pulsed-field gel electrophoresis, six were indistinguishable, the others closely or possibly related. The emergence of multiresistant, mecA-positive S. intermedius in Europe is alarming. Zoonotic implications, awareness among veterinary laboratories and strategies for the use of antimicrobials in small animal practice need to be considered.     

Acute phase response in two consecutive experimentally induced E. coli intramammary infections in dairy cows

Background

Acute phase proteins haptoglobin (Hp), serum amyloid A (SAA) and lipopolysaccharide binding protein (LBP) have suggested to be suitable inflammatory markers for bovine mastitis. The aim of the study was to investigate acute phase markers along with clinical parameters in two consecutive intramammary challenges with Escherichia coli and to evaluate the possible carry-over effect when same animals are used in an experimental model.

Methods

Mastitis was induced with a dose of 1500 cfu of E. coli in one quarter of six cows and inoculation repeated in another quarter after an interval of 14 days. Concentrations of acute phase proteins haptoglobin (Hp), serum amyloid A (SAA) and lipopolysaccharide binding protein (LBP) were determined in serum and milk.

Results

In both challenges all cows became infected and developed clinical mastitis within 12 hours of inoculation. Clinical disease and acute phase response was generally milder in the second challenge. Concentrations of SAA in milk started to increase 12 hours after inoculation and peaked at 60 hours after the first challenge and at 44 hours after the second challenge. Concentrations of SAA in serum increased more slowly and peaked at the same times as in milk; concentrations in serum were about one third of those in milk. Hp started to increase in milk similarly and peaked at 36–44 hours. In serum, the concentration of Hp peaked at 60–68 hours and was twice as high as in milk. LBP concentrations in milk and serum started to increase after 12 hours and peaked at 36 hours, being higher in milk. The concentrations of acute phase proteins in serum and milk in the E. coli infection model were much higher than those recorded in experiments using Gram-positive pathogens, indicating the severe inflammation induced by E. coli.

Conclusion

Acute phase proteins would be useful parameters as mastitis indicators and to assess the severity of mastitis. If repeated experimental intramammary induction of the same animals with E. coli is used in cross-over studies, the interval between challenges should be longer than 2 weeks, due to the carry-over effect from the first infection.     

Effect of three triploidy induction methods on the growth and survival of larvae and post‐larvae of the Caribbean scallop Argopecten nucleus

Argopecten nucleus is a small scallop from the Caribbean Sea and a relatively new species for aquaculture. One of the key challenges to develop the farming operations for this species from the current pilot scale to commercial level is to improve its harvest size. In this study, we tested three different methods for triploidy induction. Additionally, the effect of these protocols on survival, developmental rate and size of larvae and post‐larvae were assessed. Three different mechanisms to stimulate the inhibition of the release of the second polar body were tested; (1) cold shock (18°C); (2) 6‐dimethylaminopurine (6‐DMAP); (3) cytochalasin B (CB) and (4) dimethylsulphoxide (DMSO). The treatment with 6‐DMAP yielded the highest percentage of triploid larvae (39%). The survival and development rate, however, were higher in non‐treated larvae (control) than in the treatment groups. Interestingly, larvae from CB and the DMSO control groups exhibited lower growth rates in length than those from control and the other two treatments. No influence of the triploidy induction treatments was observed on post‐larvae survival, but the size of post‐larvae was larger for the cold shock treatment and DMSO control group. Our results indicate that the use of 6‐DMAP has the greatest potential to produce triploid larvae of A. nucleus without affecting negatively growth and survival of post‐larvae.     

Using cattle for conservation objectives in a Scots pine <Emphasis Type="Italic">Pinus sylvestris</Emphasis> forest: results of two trials

It has been argued that large ungulates play a key role in natural forest dynamics, but in Britain, the largest native ungulates (aurochs and elk) are extinct. Cattle could have some similar effects, and are widely used, but rarely tested, for nature conservation management. Here, we test conservation management with cattle at a native Scots pine Pinus sylvestris forest in Scotland. Our hypotheses were that cattle impacts would (a) increase the abundance of an understorey shrub of conservation importance, bilberry Vaccinium myrtillus; and (b) increase Scots pine seedling establishment. Two cattle trials were established, one for each objective, based on a 14-ha plot within the forest, and a 6.1-ha plot at the forest edge. Cattle were introduced for 2 months to both plots, giving an approximately 100- to 150-fold increase in ungulate biomass per hectare when compared to background deer abundance. The ground layer vegetation in both treatment and matched control plots was monitored before and after treatment, and subsequently over a 4-year period. At the within-forest trial, bilberry percent-cover, 4 years after treatment, was 1.9 times higher in the cattle area than in the control (95% confidence limits 1.6–2.3). Bilberry percent-cover increases were directly related to the degree of trampling impact on heather Calluna vulgaris, as recorded immediately after the trial. At the forest-edge trial, there were vegetation changes in the cattle plot that were considered favourable to pine seedling establishment: reduced moss/litter depth and vegetation percent-cover, and increased ground-level light incidence. However, too few new pine seedlings were found for formal analysis, partly due to unexpectedly low seed-fall. Nevertheless, the potential for cattle to create conditions that would subsequently promote pine regeneration was illustrated by the observation of large numbers of new, young pine seedlings at the within-forest cattle plot. We recommend that managers and researchers collaborate to develop further trials like the ones reported here, to give an improved understanding of the conditions under which cattle can yield nature conservation benefits in woodlands.