Synthesis and Anthelmintic Activity of 7-Hydroxy- 5-oxo-5H-thieno[3,2-b]pyran-6-carboxanilides and -6-thiocarboxanilides

7-Hydroxy-5-oxo-5H-thieno[3,2-b]pyran-6-carboxanilides and -6-thio-carboxanilides represent a novel series of anthelmintic compounds, with broad-spectrum activity against important parasitic nematodes in sheep and dogs. In particular, an improved efficacy against Trichostrongylus colubriformis in sheep over the related 3-carbamoyl-4-hydroxycoumarins has been noted. New synthetic routes to the key intermediate, 7-hydroxythieno[3,2-b]pyran-5-one, have been developed.     

Anthelmintic Actions of the Cyclic Depsipeptide PF1022A and its Electrophysiological Effects on Muscle Cells of Ascaris suum

The cyclic depsipeptide PF1022A, given orally to mice, showed very good anthelmintic activity against Heligmosomoides polygyrus and Heterakis spumosa at 50 mg kg⁻¹. In vitro, PF1022A was very active against Trichinella spiralis and had good activity against Nippostrongylus brasiliensis at 1 μg ml⁻¹. An 18-membered enniatin analogue, JES 1798, showed good activity only against N. brasiliensis at 10 μg ml⁻¹. The optical antipode of PF1022A had poor activity even at 100 μg ml⁻¹. The effects of PF1022A on the membrane potential and input conductance of somatic muscle of Ascaris suum were examined using a two-microelectrode current-clamp technique. PF1022A did not antagonize the effects of the selective nicotinic agonist levamisole. PF1022A and an analogue, JES 1798, but not the PF1022A antipode, produced a small time-dependent increase in input conductance associated with no potential change. The increase in input conductance did not occur in the Cl⁻-free bathing solution, suggesting that the increase in input conductance was mediated by Cl⁻ ions. The addition of high concentrations of Ca²⁺ to the preparation after the addition of PF1022A did not lead to production of Ca²⁺-activated Cl⁻ channels, suggesting that its mode of action was not that of a Ca²⁺ ionophore. The mechanism by which the cyclic depsipeptide might increase the Cl⁻ conductance is discussed.     

Application of sperm cryopreservation in selective breeding of the Pacific oyster,Crassostrea gigas (Thunberg)

The robustness of Pacific oyster, Crassostrea gigas (Thunberg), sperm cryopreservation in the context of selective breeding based on family lines was investigated. Irrespective of egg density, high fertilization success was achieved with cryopreserved sperm when sperm:egg ratios of 1000:1 to 10 000:1 were used. Variation among replicate runs on the same oyster batches was minimal, indicating that cryopreservation and larval rearing procedures were repeatable. Twenty independent single male–female crosses were made to assess the utility of cryopreserved sperm in selective breeding. The fertility of unfrozen sperm was generally a poor predictor of cryopreserved sperm fertility. Based on D‐larval yields, 17 of the 20 crosses were likely to yield adequate spat for selective breeding (>10⁵ D‐larvae from 1 million eggs), two were marginal (5 × 10⁴ D‐larvae) and one was inadequate (4 × 10³ D‐larvae). An alternative fertilization strategy to improve D‐yield from a given number of sperm was then tested. Fertilizing 10 million eggs at a sperm:egg ratio of 200:1 increased the total D‐yield when compared with fertilizing 1 million eggs at a sperm:egg ratio of 2000:1 for the same male–female pair. We conclude that, despite wide variation in fertility, cryopreserved sperm is useful for family production.     

Optimising spring oral vaccination campaigns of foxes against rabies

To optimise spring vaccination campaigns the following set of data has been analysed; (i) population dynamics of the red fox, (ii) onset and progress of the reproductive season, and (iii) maternal immunity and the immune response of fox cubs to oral vaccination. The field data originated from foxes caught in Bavaria, Germany. The results of our analysis clearly demonstrate that certain periods during spring are less suitable for bait distribution. If the objective of a vaccination campaign is to reach only the adult foxes, it is suggested to conduct the campaign during the first half of March. If also young foxes are to be vaccinated, baits should not be distributed before the end of May in previously baited areas, because a large segment of the young fox population can not be vaccinated effectively before this date as a result of maternally transferred immunity. In areas vaccinated for the first time, baits can be distributed earlier, since 5 weeks old cubs are already immunocompetent.     

Wie werden Wachstumsparameter von Gehölzen auf unterschiedlichen Standorten durch das Verschulen beeinflusst?

The influence of transplanting on height, root neck diameter, and grading was investigated for Carpinus betulus, Quercus robur, and Euonymus europaeus on three sites with different climate and soil properties. Additionally, plant growth was characterized by the shoot-to-root ratio, height-to-root neck diameter, and proportions of coarse and fine roots. The significance of the growth parameters as criteria for survival is discussed. Transplanting influenced shoot growth more than root growth. The growth of the plants was highly site-dependent. Transplanting increased growth most on the site with the best conditions for water and N supply. Transplanting had no effect on grading for the site with the worst water supply.     

CO2-stunning of swine for slaughter from the anesthesiological viewpoint

For investigations of CO2-stunning of feeder- and slaughter-pigs parameters of behaviour, blood-gas-analyses and electroencephalograms were chosen. The following results were obtained: 1. Blood-gas-analyses proved that the CO2-stunning does not produce unconsciousness due to a lack of oxygen. 2. The criterias of general anaesthesia: unconsciousness, muscle-relaxation and analgesia with total reversibility could be confirmed. 3. The violent convulsive symptoms were evaluated as reactions identical with the stage II of GUEDEL's scheme of anaesthesia. 4. Muscular agitation, which sometimes appeared a few seconds before the stage of excitation, was judged to belong either to the start of the excitation phase or to the end of Guedel's stage of analgesia, during which the sensitivity is decreased. Neither study of behavior nor objective measurements showed, during the first 10 to 20 seconds of exposure to the CO2, any sign of pain or suffering related to the Act for Prevention of Cruelty to Animals, and accordingly such suffering should not be ascribed to the CO2 stunning method.     

Meine Erfahrungen mit Arsenbrühen zur Bekämpfung von Obstbaumschädlingen

Ohne Zusammenfassung     

Schmeißfliegen (Calliphoridae) und vakuumverpackter Schinken

Blowflies (Calliphoridae) and vacuum-packed ham In a few cases blowfly maggots have been reported from vacuum-packed ham. The possibility of egg-hatching and larval development in the product was analysed. In experiments no hatching of blowfly eggs on vacuum-packed, boiled, sliced ham occurred. However, the eggs are not killed immediately; 1–4 days after the packing, they are still viable and when the wrapping is broken, hatching may occur. After a stay of 7–10 days on vacuum-packed ham, the viability of the eggs seems lost. In the actual case the risk of oviposition by blowflies on ham in the cannery and succeeding larval development in the product is considered to be very low.     

Effect of consumption of organically and conventionally produced apples on antioxidant activity and DNA damage in humans

The present study was performed to compare the effects on antioxidant activity and on DNA damage of organic and conventionally produced apples grown under controlled conditions in human peripheral blood lymphocytes. Six healthy volunteers consumed either organically or conventionally grown apples (Golden Delicious, 1000 g) from two neighboring commercial farms in a double-blinded, randomized, cross-over study. The average content of total identified and quantified polyphenols in the organically and conventionally produced apples was 308 and 321 microg/g fresh weight, respectively. No statistically significant differences in the sum of phenolic compounds or in either of the polyphenol classes were found between the agricultural methods. Consumption of neither organically nor conventionally grown apples caused any changes in antioxidant capacity of low-density lipoproteins (lag time test), endogenous DNA strand breaks, Fpg protein-sensitive sites, or capacity to protect DNA against damage caused by hydrogen peroxide. However, a statistically significant decrease in the levels of endonuclease III sensitive sites and an increased capacity to protect DNA against damage induced by iron chloride were determined 24 h after consumption in both groups of either organic or conventionally grown apples, indicating the similar antigenotoxic potential of both organically and conventionally grown apples.     

The inhibition by ammonia of population growth of the rotifer, Brachionus rubens, in continuous culture

For the safe maintenance of microalgae and rotifers in mass culture, it is necessary to know the exact threshold concentration of ammonia for rotifers. In order to determine this threshold concentration, the continuous culture technique was used as a sensitive method to determine the influence of ammonia on the reproduction rate of the rotifer Brachionus rubens. As expected, only unionized (free) ammonia affected the population growth. Up to a concentration of 3 mg $\text{NH}{}_3\text{-N}\text{l}$ the reproduction of Brachionus was unaffected. In the range of 3–5 mg $\text{NH}{}_3\text{-N}\text{l}$ the reproduction rate decreased, although no animals were killed. This decrease was reversible and could be overcome by lowering the NH₃-N concentration. At concentrations over 5 mg $\text{NH}{}_3\text{-N}\text{l}$ the rotifers died within 2 days.