Spatial Distribution of 137CS in Forest SOils of Switzerland

In the framework of the second Swiss forest soil inventory, ¹³⁷Cs-activity from 172 sites was measured systematically for the first time in the topmost soil layer (0–5 cm) and represented on a map. The spatial distribution of ¹³⁷Cs contamination was similar to the pattern observed in 1986 from dose equivalent measurements following the Chernobyl nuclear power plant accident. Forest soils from regions with high precipitation in 1986 showed a higher ¹³⁷Cs activity than regions with low precipitation. At sites with high caesium activities it was possible to discriminate between ¹³⁷Cs originating from global fallout of the fifties and sixties and ¹³⁷Cs from the Chernobyl accident. The results indicate that radiocaesium persists in the top soil layers and is recycled in forest ecosystems.     

The occurrence of terrestrial algae on two beech sites on a Cambisol

The occurrence of terrestrial algae on two beech sites was determined qualitatively and quantitatively in the litter, organic and mineral layer. Both sites are beech stands of different age and the soil type is a Cambisol. On the site with young beech the maximal value determined was 1.0 · 10⁸ algae g^?1 dw in the litter layer. With increasing soil depth the number of algae decreased on both sites, and at the young beech stand site no algae were found in the mineral soil. Chlorophyceae were the dominant algae group and at the young beech stand Bacillariophyceae were present.     

Analyses of stand structure as a tool for silvicultural decisions — a case study in a Quercus petraea — Sorbus torminalis stand

The study applies structural indices using the example of an oak (Quercus petraea (Matt.) Liebl.) — chequer tree (Sorbus torminalis (L.) Crantz) stand in order to derive recommendations for the silvicultural treatment of Chequer trees. The investigated stand, located in the northern part of Bavaria, comprises eight tree species and four shrub species. Various indices were used to analyse the stand structure and the crown coverage frequency. It was shown that chequer trees, which are presently of high economic interest, are strongly oppressed in the upper layer and almost completely missing in the lower layers of the stand. The possible reasons for this finding and alternatives for the further management of the stand are discussed. Persistent and repeated thinnings in order to ensure sufficient crown development of the chequer trees seem to be essential for their survival.     

Chemical deterrents in podurid Collembola

Four aromatic compounds (2,4-dimethoxyaniline, 1,3-dimethoxybenzene, 2-aminophenol, phenol) found in Neanura muscorum (Collembola, Neanuridae) have been investigated for their role as deterrents against the predatory mite Pergamasus norvegicus (Acarina, Parasitidae). 2-Aminophenol has deterring properties against P. norvegicus, the other substances show no effect as single substances nor is there a synergistic effect.The reaction of three predators, Microvelia reticulata (Heteroptera, Veliidae), Gambusia affinis (Teleostei, Cyprinodontidae) and Rana temporaria (Amphibia, Ranidae) on Podura aquatica (Collembola, Poduridae) is reported. The strongest deterring effects of P. aquatica could be observed with G. affinis. M. reticulata also shows behavioural changes that can be attributed to deterring effects of P. aquatica. The collembolan has no deterring effects on R. temporaria.A synopsis of literature dealing with deterring effects of collembola on arthropod predators is given.     

Regulation of bovine labor with a long-acting carba-analog of oxytocin: a preliminary report.

The long-acting oxytocin (OT) analog 1-desamino-1-monocarba-E12-Tyr(OMe)]-OT(dCOMOT) was given IV to 13 pregnant cows near to term, but not in actual labor. The animals were para 1 to 5. Of these cows, four were treated with 20 mg of dexamethoasone 48 hours before the peptide was injected; the remaining nine animals were given no other medication. The animals usually were given a single injection of 5 mg of dCOMOT into the jugular veiw (5 to 7 micrograms/kg of body weight). In those instances where delivery was not complete within six hours, a second injection of peptide was given. In all instances, the first injection initiated labor as judged by the behavior of both uterus and cow. In most instances, there was also intermittent spurting of colostrum from the udder over a six-hour period after injection. In the four cows treated first with dexamethasone, the mean duration of induced labor was 4.35 hours after dCOMOT injection. In the nine non-treated cows, the mean duration of induced labor was 14.25 hours. The difference between the two values was significant. For both groups separately, and all data together, there was a linear inverse relation between the size of the external ostium uteri at injection and the duration of labor after peptide injection. All calves were healthy with no signs of hypoxia and the dose rates used did not result in any instance of uterine tetany or tachyphylaxis.     

Levels of progesterone, 17 beta-estradiol and 11-hydroxycorticosteroid in the blood in cows in different types of puerperal conditions

Changes in progesterone (P4), 17 beta-estradiol (E2) and 11-hydroxycorticosteroid (11-OHCS) concentrations in blood plasma were determined in daily intervals from the day of parturition to day 15 post partum (p.p.) in cows with physiological puerperium (n = 8), with puerperal endometritis (n = 6), and with placenta retention (n = 6). Cows with puerperium disorders (endometritis, placenta retention) had significantly higher P4 levels in the period from day 3 to day 7 p.p. than cows with physiological puerperium. E2 concentrations decreased to basal values following the parturition in cows with spontaneous parturitions and subsequent expulsion of the placenta. A delayed decrease in E2 concentrations after parturition and a significant increase on day 5 and day 7 p.p. were recorded in the group of animals with placenta retention. Significantly higher levels of 11-OHCS in blood plasma were detected by day 5 or by day 8 p.p. in cows with placenta retention and puerperal endometritis. Extraovarial sources of sexual steroids resulting in endocrine malfunctions are discussed as well as likely consequences for puerperium.     

Plasminogen activation in the bovine udder

Plasmin is a serin protease with a broad substrate specificity which might cause disintegration of basal membranes, epithelium and surrounding matrix. Plasmin might also elicit degradation of tissue (Mullins & Rohrlich 1983).     

Colonization Patterns and Densities of Zebra Mussel Dreissena in Muddy Offshore Sediments of Western Lake Erie, Canada

Zebra mussels (Dreissena) have expanded rapidly throughout most of the Laurentian Great Lakes since their inadvertent release in 1986. These exotic molluscs now occur in great numbers on the bottom of western Lake Erie where they are found increasingly in deeper areas of the basin (average depth: 10 m), on soft, muddy substrates. This study is aimed at quantifying the density and the distribution patterns of mussel colonization in the basin as a first step in investigating the effect on sediment properties of such an abrupt change in benthic community structure. Underwater video imagery and diver-collected samples taken from representative o shore areas (seven sites) in western Lake Erie showed colonization levels of up to 20,000 live mussels per m² in soft sediments (adults with shells >10 mm comprised 47%). Digital side-scan sonar records confirmed that colonization patterns were not random, but showed distinctive spatial signatures ranging from 30-m-long parallel stripes, to large ovate masses. Broad irregular mats were found in association with hard bottoms (bedrock, boulders, or wrecks and large debris). Mussel densities were averaged from the sites, assuming consistent relationships with substrate type and were combined with digitized percentage of areal coverage of major bottom types in western Lake Eric. This resulted in the first population figure of 10¹³ in the basin. This figure includes molluscs ofall sizes > 0.84 mm.     

Distribution of the Cinnabar moth Tyria jacobaeae L. at landscape scale: use of linear landscape structures in egg laying on larval hostplant exposures

The distribution of the xerothermophilous Cinnabar moth Tyria jacobaeae was studied in a low mountain region in western Germany between 1989 and 2001. T. jacobaeae started its immigration into the study area in 1989 and first established populations in climatically favoured habitats like abandoned quarries and train stations where the larval host plant, ragwort (Senecio jacobaea), occurs. Analysis of landscape features (altitude, morphology) reveals that T. jacobaeae then dispersed along valleys with roads to higher altitudes of the study area. Elevations of occupied sites increased between 1989 and 2001. In order to investigate whether dispersal is affected by linear structures like valleys or roads with gravelled verges, hostplant exposures were placed at a distance of 600 m to the next population of T. jacobaeae. The experiments suggest that egglaying predominantly took place on exposures in valleys with roads and sparsely plant-covered verges but can also occur along valleys lacking roads and suitable habitats. However, larvae were never recorded on Senecio exposures which were placed aside from valleys and roads.This revised version was published online in May 2005 with corrections to the Cover Date.     

The effect of intramuscular administration of colistin on the development and course of experimentally induced oedema disease in weaned piglets

Shiga-toxigenic E. coli (STEC) strains that produce Shiga toxin Stx2e cause oedema disease in weaned piglets. The purpose of the present study was to investigate the impact of Stx2e released in mesenteric lymph nodes on disease pathogenesis. Colistin and ampicillin were intramuscularly administered to piglets of the experimental group simultaneously challenged with STEC strain, type O139:F18ab, Stx2e+. Piglets of the control group were challenged with STEC only. The strain was naturally resistant to ampicillin and susceptible to colistin. After the challenge, colonisation of the intestines was observed in both antibiotic-treated piglets and control piglets without antibiotic treatment. Histochemistry and scanning electron microscopy revealed sporadic colonisation of the small intestine in the piglets. STEC was detected in the mesenteric lymph nodes of untreated piglets. The clinical manifestations of oedema disease were observed in both groups. In the antibiotic-treated group (11 piglets), oedema disease developed in 10 piglets, eight of which died or were euthanized ante finem. In the untreated group (11 piglets), oedema disease developed in five piglets, four of which died or were euthanized ante finem. We therefore propose that the STEC lysed by colistin suddenly released the toxin from bacterial cells immediately after their passage through the intestinal wall. That could explain a more severe course of oedema disease in the treated piglets. Even though high amounts of STEC were present in the lymph nodes of untreated piglets, the toxin was not released abruptly because the bacterial cells were not damaged.