The rarely reported tet(31) tetracycline resistance determinant is common in Gallibacterium anatis

The present investigation was undertaken to identify and characterize the tetracycline resistance determinant in 22 Gallibacterium anatis strains for which no determinant was identified using primers specific for tet(A, B, C, D, E, G, H, K, L, M, O). A recent study found tet(B) to be the most prevalent tetracycline resistance determinant in a larger collection of G. anatis field strains from Mexico and Denmark. However, in 41% of the tetracycline resistant strains no determinant could be assigned. Here we demonstrate that tet(31) is a common determinant in G. anatis originating from chickens from very different production systems and localities. In addition, tet(31) was identified in strains isolated over a 30-year period. This is the first report on tet(31) since its original identification in Aeromonas salmonicida.     

Impact of Urban Stormwater on Sediment Quality in an Enclosed Bay of the Lule River, Northern Sweden

Sediment and porewater samples from an enclosed bay receiving stormwater discharge (Skutviken) near the centre of Lule?, northern Sweden were analysed for major and trace elements and 16 polycyclic aromatic hydrocarbons (PAHs). Among the studied metals Cd, Cu, Pb and Zn were enriched at Skutviken. Also, the PAH content was enriched, in particular for phenantrene, anthracene, fluoranthene and pyrene which are regarded as common constituents in stormwater. The use of trace metal ratios provided indications about pollutant sources for the sediment. Cs-137 dating was used to determine historical changes in metal and PAH fixation in the sediment. The bay Skutviken is enclosed through the construction of a road bank since 1962. The enclosure led to reduced water circulation in the bay that promotes the occurrence of anoxic conditions with sulphate reduction within the bay. As a consequence of these conditions, metals are trapped in the sediments as sulphides. This study suggests that enclosed bays with restricted water circulation may be efficient traps for urban pollutants, reducing the present-day input of pollutants to the sea. In areas with postglacial land uplift, where such bays are common, bay sediments are a potential future source of pollutants when uplift results in erosion and oxidation of the sediments.     

Olfactory response of Myzus persicae (Homoptera: Aphididae) to volatiles from leek and chive: Potential for intercropping with sweet pepper

Abstract

Odour-mediated effects of leek Allium porum and chives Allium schoenoprasum (Alliaceae) on the host searching behaviour of the aphid Myzus persicae (Sulzer) (Homoptera: Aphididae) were studied. In an olfactometer, odour of the host plant sweet pepper Capsicum annuum L. (Solanaceae) was significantly attractive, whereas odour of chives was significantly repellent. Combined odour of sweet pepper and chives was neither attractive nor repellent. When sweet pepper plants were exposed to volatiles from chives for five days, their odour subsequently became repellent to M. persicae. An extract of leek plants was significantly repellent to aphids in the olfactometer, as were sweet pepper plants sprayed with this extract. Because both leek and chives can disrupt host finding by the aphid, both plants have potential for intercropping with sweet pepper. If successful in the field, such a system could bring economic benefits for farmers in the wet zone of Sri Lanka and other parts of the world.     

Food sources of early colonising arthropods: The importance of allochthonous input

Arthropod predators and detritivores are among the first colonisers on land surfaces undergoing primary succession. In the absence of higher plants and herbivores, they may either have an allochthonous food source (i.e. of geographically distant origin) or local food source that is sustained by e.g. microorganisms. By studying spiders and collembolans on sites along chronosequences on recently emerged nunataks (ice-free land in glacial areas), we analysed whether the food source of early colonisers was of local or distant origin. Also, we measured the potential changes in trophic position with increasing site age. With stable carbon and nitrogen isotope analysis of both spiders and collembolans, we determined that allochthonous food sources are important on the youngest sites. The allochthonous food sources may explain how arthropods can persist in the absence of local primary productivity. Also, some spider species may increase their ability to survive by shifting their trophic position as the community composition changes. The results indicate that a wolf spider species shifted towards a lower trophic level with increasing site age. By contrast, no shifts in trophic position were observed for sheet-web spiders or collembolans.     

Automatic blood sampling in dairy cows

Loose housing systems for dairy cows are becoming increasingly common, raising new questions in the area of animal health and welfare. Some of these questions can be addressed by studying the variation in blood parameters, such as glucocortistioids. However, the traditional manual blood sampling procedure can in itself affect the responses of the animal. To address this issue we have developed a device for automated collection of multiple blood samples. The device is placed on the back of the animal and allows the animal to be kept in all types of environments, either alone or in social groups. The animal can move freely: no restraints and no handling of the animal are necessary during blood sampling.Three experiments were conducted to study the performance of the system and how the blood sampling procedure affected the cortisol responses in dairy cows. In the first experiment the accuracy of sample size and timing were investigated.In the second experiment, automatic samples were collected from six cows kept in tie-stalls, with samples taken at 3-min intervals for 38 min. At 12, 24, 36 and 38 min, a manual sample was taken by vein puncture. None of the cows showed a consistently increased cortisol response to automatic sampling, while two cows showed increased cortisol concentration after vein puncture.In the third experiment automatic blood sampling was conducted with 12 cows kept in a loose housing system. In the morning, over a period of 1.5 h, 14 blood samples were taken at varying time intervals from each cow. In the afternoon, over a period of 2.5 h, a further 14 samples were taken. Cortisol concentrations in the blood samples suggest that the cows were not affected by the blood sampling procedure.On some occasions during these experiments, it was not possible to get a sample. For the manual vein puncture 3 out of 24 samples (12.5%) were not successfully taken within a time limit of 2 min. During the automatic blood sampling process, the catheter occasionally became twisted and blocked by the movement of the cow's head. This occurred in 8 out of 84 samples (9.5%). In four of the manual samples, considerable hemolysis had occurred during the sampling procedure. No hemolysis was observed in the automatic blood samples.Automated blood sampling offers the opportunity to collect a series of samples without disturbing the animal. Data suggest that automatic blood sampling is a superior alternative to manual blood sampling, even in a tie barn.     

Predacious activity of the nematode-trapping fungus Duddingtonia flagrans against cyathostome larvae in faeces after passage through the gastrointestinal tract of horses

This study was undertaken to examine the potential of the nematode-trapping microfungus Duddingtonia flagrans to survive passage through the gastrointestinal tract of horses and subsequently to destroy free-living stages of cyathostomes in faecal cultures. Three different oral dose levels were tested, two horses being used for each level. Faeces were collected twice daily and the number of parasite eggs per gram of faeces were determined. The numbers of infective third stage larvae which developed in faecal cultures were determined after the cultures had been incubated for 2 weeks at 24°C. Results showed a positive relationship between dose level and reduction in the number of infective larvae. Fungi were recovered in faeces at times which corresponded to high larval reduction.     

CEREBRAL VENTRICULAR SIZE IN DEVELOPING NORMAL KITTENS MEASURED BY ULTRASONOGRAPHY

To evaluate the age of fontanelle closure of normal kittens and the size of their lateral ventricles, 50 ultrasonographic examinations using the bregmatic fontanelle as an acoustic window were made. Seven kittens, laboratory animals, were included in the study. To verify the location of the lateral ventricle, two of the kittens were sacrificed as neonates. In one of them ink was injected prior to autopsy into one lateral ventricle under sonographic guidance. In a longitudinal study of five of the kittens, the skull depth and the depth of the central part of the lateral ventricle reproduced in a longitudinal view could be measured up to the age of about 5 months. During that period, the skull depth increased from a median value of 1.95 cm (1.92-1.98) in a seven-day-old cat to 2.58 cm (2.52-2.59) in a 154-day-old cat, while the afore-mentioned ventricle values increased from 0.3 mm to 1.1 mm.     

Is coppice a potential for urban forestry? The social perspective

After years of decline and neglect, low woodland types based on coppice management experience renewed interest. Substantial research has demonstrated the potentials of coppice for biomass production and for nature conservation, and coppices are increasingly being suggested for urban situations. Yet, our understanding of the more social aspects of coppice woodlands in modern urban situations is limited. Against this background, this contribution classifies coppice management systems as a basis for identification of social aspects of coppices and their potential use in contemporary urban forestry. Based on this classification, the social perspectives and potential niches for urban coppices are discussed, while lines of research are suggested which will support the development of a thorough and up-to-date knowledge base, against which the social merits of urban coppice woodlands can be critically evaluated.     

Marine migrations in anadromous brown trout (Salmo trutta). Fjord residency as a possible alternative in the continuum of migration to the open sea

Partial migration is a common phenomenon in many fish species. Trout (Salmo trutta) is a partially migratory species where some part of the population migrate to the marine environment, while another remains in freshwater. In the years 2008 and 2009, a total of 159 wild sea trout smolts were tagged with acoustic and PIT‐tags in the river Villestrup (Denmark) to study the initial postsmolt marine behaviour within a fjord system. We found that the strategies of the sea migrants vary: some stay in the fjord, while others migrate to the sea, suggesting that partial migration occurs even in the marine environments. Overall, a total of 53% of the tagged smolts migrated from the fjord to the sea, and 47% stayed (or potentially died) in the fjord. The ratios of fjord‐resident versus sea‐migrating postsmolts were consistent at the study times, and no differences between the early and late migration periods of the smolts were observed. The individual's size or body condition at the time of tagging did not affect survival or the migratory decisions in the fjord. High overall initial survival (74%) was found 30 days after the fjord entry. We suggest that within a continuum of migration to sea, there is a migratory decision point when sea trout postsmolts encounter a fjord system. At this point, postsmolts will assess the possibility of migration versus the alternative of fjord residency.