Can field populations of the enchytraeid,Cognettia sphagnetorum,adapt to increased drought stress?     

Kristine Maraldo  Inger Kappel Schmidt  Claus Beier  Martin Holmstrup 《Soil biology & biochemistry》2008,40(7):1765-1771

The ability to evolve increased drought tolerance in response to climate change was investigated in the enchytraeid, Cognettia sphagnetorum. Populations exposed to reduced precipitation or increased night time temperature for more than six years were collected in mixed Calluna/grass heathland at the Mols Laboratory, Denmark. The level of prolonged drought and increased temperature corresponded to a predicted climate change scenario and has been applied since 1999. In autumn 2005, enchytraeids were sampled in 3 cm intervals down to 9 cm depth and total number, biomass, diversity and soil organic matter were determined. The drought treatment resulted in a significant reduction of the density and biomass of enchytraeids, as well as changes in the species composition. In total, five different genera were found at the site in all three treatments (control, temperature and drought). C. sphagnetorum was the dominant species, especially in the upper 0–3 cm, and was clearly affected by the drought treatment. C. sphagnetorum from all plots were cultured in the laboratory to rear second or third generation adults. Results showed that populations of drought treated plots had not developed an increased drought resistance compared to populations of control or warming plots even after several years of a putative severe selection. Lack of adaptive potential in C. sphagnetorum suggests that more frequent periods with drought in the future will have a very strong negative influence on enchytraeid density, biomass and diversity.  相似文献   

Restoration of bracken-invaded Calluna vulgaris heathlands: Effects on vegetation dynamics and non-target species     

Inger Elisabeth Mren  Vigdis Vandvik  Kristine Ekelund 《Biological conservation》2008,141(4):1032-1042

The coastal heathlands of north-western Europe are endangered habitats of great conservation value. Invasion by bracken Pteridium aquilinum is a major challenge for conservation and restoration of these heathlands, including the under-studied northern regions. Today, the herbicide asulam is the most widely applied bracken control measure, but increasing focus on organic farming and nature conservation calls for alternative, preferably mechanical, approaches. In a 7-year replicated field experiment in western Norway, we investigated efficiencies of the four bracken control measures asulam, Gratil, annual cutting and biannual cutting, in restoring the characteristic heathland vegetation structure and species composition. We specifically tested herbicide effects on diversity and composition of non-target species. Effects of treatments over time were evaluated by repeated measures ANOVA, and for multivariate data, Principal Response Curves. Our results show that UK based control methods are largely applicable to bracken at its northern limit in the European heathland habitat. Asulam resulted in the fastest reduction in cover but cutting proved equally efficient long-term. Community compositions progressed towards desired heathland vegetation, but successional trajectories differed. Asulam had unintended effects on a number of heathland species not predictable by species characteristics or functional groups. Gratil failed to have any long-term effects. In summary, cutting is as efficient as herbicide application in reducing bracken, and more so in restoring northern heathland vegetation over time.  相似文献   

PLasma Cholesterol in Swine Genetic Variations and Relation to Alkaline Phosphatase     

Inger Wegger 《Acta veterinaria Scandinavica》1978,19(3):469

A variety of environmental factors such as feeding and climate may influence the plasma cholesterol concentration. Earlier experiments have, however, indicated that genetic differences also exist (Heidenreich et al. 1964). The present study was undertaken to elucidate this possibility in pigs of Danish Land-race reared under strictly standardized environmental conditions. Besides, the plasma cholesterol concentration was compared with other genetically variable blood parameters to examine if any correlations existed. Only the relation to alkaline phosphatase (AP) will be dealt with here.  相似文献   

Experimental Maedi Infection in Sheep: 2. Antibody Response     

Nabila Gazia  Inger Wegger 《Acta veterinaria Scandinavica》1980,21(1):124

All 4 sheep inoculated via the respiratory tract with 7×10⁶ TCID50 af maedi M88 strain developed complement fixing (CF) antibodies within 3 months after inoculation, and a gradual rise in CF titers was found during the first year. The antibody titers have been maintained, though with some fluctation, through the following year, and the titers vary from 64 to 256. Virus neutralizing activity against maedi M88 strain was detected in the sera of all intrapulmonarily inoculated sheep within 8 months after inoculation. Titers have been maintained or have slightly increased. The level of titers, ranging from 8 to 256, was clearly different between individual sheep.One of the 4 sheep inoculated intracerebrally with 5×10⁵ TCID50 of maedi M88 strain developed CF antibodies 1 month after inoculation, but no neutralizing antibodies until death 11 months after inoculation. The rest of the intracerebrally inoculated sheep displayed no evidence of CF or neutralizing antibodies within 18 months after inoculation in spite of numerous virus isolations from peripheral blood leukocytes. The absence of antibodies might perhaps be attributed to phenomena such as differences in tropism, provirus state, immunological tolerance and size of inoculum.One sheep hyperimmunized with repeated s.c. and i.v. injections of maedi M88 strain developed high CF antibody titers but lower neutralizing antibody titers.The 2 uninoculated control sheep developed no CF or neutralizing antibodies within 18 months after inoculation.  相似文献   

Effect of feeding different levels of foliage of Moringa oleifera to creole dairy cows on intake, digestibility, milk production and composition     

Nadir Reyes Snchez  Eva Sprndly  Inger Ledin 《Livestock Science》2006,101(1-3):24-31

An experiment was conducted in Nicaragua to determine the effect of feeding different levels of foliage from Moringa oleifera Lam (synonym: Moringa pterygosperma Gaertner) to dairy cows on intake, digestibility, milk production and milk composition. The treatments were: Brachiaria brizantha hay ad libitum, either unsupplemented or supplemented with 2 kg or 3 kg of Moringa on a dry matter (DM) basis. Six Bos indicus cows of the Creole Reyna breed, with a mean body weight of 394 ± 24 kg were used in a replicated 3 × 3 Latin square design. Supplementation with Moringa increased (P < 0.05) DM intake from 8.5 to 10.2 and 11.0 kg DM day^− 1 and milk production from 3.1 to 4.9 and 5.1 kg day^− 1 for B. brizantha hay only and supplementation with 2 kg and 3 kg DM of Moringa, respectively. Milk fat, total solids and crude protein and organoleptic characteristics, smell, taste and colour, were not significantly different between the diets. Apparent digestibility coefficients of DM, OM, CP, NDF and ADF increased (P < 0.05) in the diets supplemented with Moringa compared with B. brizantha hay alone. The results showed that the inclusion of Moringa as a protein supplement to low quality diets improved DM intake and digestibility of the diet and increased milk production but did not affect milk composition.  相似文献   

Effects of Daily Oral Administration of Copper to Goats     

Nils E. Sli  Inger Nafstad 《Acta veterinaria Scandinavica》1978,19(4):561

Three goats were dosed orally with a 0.2 % aqueous copper sulphate solution. The dosing was 20 mg copper sulphate/kg body weight twice a day for 56 to 113 days. One of the goats accumulated substantial amounts of copper in the liver and developed two haemolytic crises. The two other goats showed only increased liver copper concentrations before they were killed. The results indicate that the goats were susceptible in varying degrees to repeated oral copper dosing, and that two of the goats were significantly less susceptible to copper than sheep. The goat that turned into a haemolytic crisis showed changes similar to those seen in sheep as far as blood and plasma parameters are concerned. The gross and histological lesions were also mainly of the same type as described in sheep. The hepatic lesions found in the goat differed to some degree from those found in sheep as the necroses were more distinctly located to the centrilobular area, and as the iron pigments were mainly located in phagocytes in the hepatic sinusóides.  相似文献   

Weed control measures in Christmas tree plantations of <Emphasis Type="Italic">Abies nordmanniana</Emphasis> and <Emphasis Type="Italic">Abies lasiocarpa</Emphasis> on agricultural land   总被引：1，自引：1，他引：0  

Arne Sæbø  Inger Sundheim Fløistad  Jan Netland  Brynjar Skúlason  Øyvind Meland Edvardsen 《New Forests》2009,38(2):143-156

Abies nordmanniana and Abies lasiocarpa, established for Christmas tree production in southwestern Norway (58°44′N, 5°38′E), were treated with different weed control methods, including chemicals, use of black plastic mulch, grass or clover as ground cover, living mulch and mechanical hoeing. Ground cover with black plastic mulching resulted in the best growth and quality in A. lasiocarpa; the least favourable treatment was when grasses were allowed to grow close to the trees. Unless measures were taken to remove this competing vegetation, the ground cover grew over the trees, smothering 94% of them. A. nordmanniana plants grew to the same height on plots with no weed control as on plots with thorough weed eradication. Stem diameter decreased on plots with ground vegetation compared to seedlings grown in the weed-free environment. The use of Trifolium repens as ground cover decreased height growth by 30% compared to thorough weed control. Both grasses and clover sown as living mulch, damaged the trees more than did natural weed vegetation.  相似文献   

Natural zooplankton as larval feed in intensive rearing systems for juvenile production of Atlantic cod (Gadus morhua L.)     

Kjersti Eline Tønnessen Busch  Inger‐Britt Falk‐Petersen  Stefano Peruzzi  Nora Arctander Rist  Kristin Hamre 《Aquaculture Research》2010,41(12):1727-1740

The growth potential of cod larvae is not fully achieved when rotifers (Brachionus spp.) are used as live feed. In this experiment, we studied the effect of natural zooplankton (mainly copepods) on the growth of cod (Gadus morhua L.) larvae reared in intensive systems. Using a growth model developed for cod larvae, the growth rates observed could be evaluated and compared with growth rates reported previously. The cod larvae showed optimal growth rates until age 19 days post hatch (DPH) when they reached 9.77 ± 0.25 mm standard length (SL). Early weaning (20–25 DPH) resulted in significantly longer larvae at age 30 DPH compared with late weaning (25–32 DPH); however, in this period, the zooplankton concentrations were low. The experimental larvae showed considerably higher growth rates compared with rotifer (Brachionus spp.)‐reared cod larvae in previous experiments. The nutritional composition of cod larvae was analysed and compared with published results on rotifer‐reared larvae. The levels of iodine, manganese, selenium and n‐3 PUFA were considerably higher in larvae fed copepods compared with larvae fed rotifers. The differences in nutritional status may well explain the differences in growth observed between copepod and rotifer‐reared larvae.  相似文献   

Seasonal variations and effects of nutrient applications on N and P and microbial biomass under two temperate heathland plants     

Pia L. Nielsen  Louise C. Andresen  Anders Michelsen  Inger K. Schmidt  Jane Kongstad 《Applied soil ecology》2009,42(3):279-287

Eutrofication is a threat against nutrient-poor habitats as increased amounts of nutrients in ecosystems may cause changes in the vegetation. Nitrogen (N) deposition leads to conversion of Calluna heathlands into graminoid dominated heath, but low availability of P may hinder or slow down this process.In this study the soil properties under two dominant heathland plants, the dwarf shrub Calluna vulgaris and the grass Deschampsia flexuosa, were investigated, with focus on nutrient content in the organic top soil and soil microbes during the main growing season and effects of nutrient amendments. The concentration of inorganic and dissolved organic N was significantly higher under D. flexuosa than C. vulgaris all though there were the same amounts of total N in the soil below the two species. N and P amendment enhanced available N and P in the soil, but added nutrients had little direct effects on microbes. The microbial biomass on the other hand was positively related to soil water content in fertilized plots indicating that this was due to an indirect effect of enhanced nutrient availability. Microbial N and P pools were respectively 1000 and 100 times higher than the pool of inorganic N and P, and microbes therefore may play an important role in regulating plant nutrient supply. Judged from responses of inorganic and microbial N and P concentrations to added N and P, N seemed to limit C. vulgaris and soil microbes below while P seemed to limit D. flexuosa and soil microbes below this species. There were lower rates of net nitrification, net ammonification and DOC and DON production rates during winter in the soil under C. vulgaris than below D. flexuosa, although all these rates were equal under the two species on an annual basis. This indicates that these microbial processes were taking place during winter but were affected by exudates from C. vulgaris.  相似文献   

Isolation and Characterization of Anti-Adenoviral Secondary Metabolites from Marine Actinobacteria     

M?rten Strand  Marcus Carlsson  Hanna Uvell  Koushikul Islam  Karin Edlund  Inger Cullman  Bj?rn Altermark  Ya-Fang Mei  Mikael Elofsson  Nils-Peder Willassen  G?ran Wadell  Fredrik Almqvist 《Marine drugs》2014,12(2):799-821

Adenovirus infections in immunocompromised patients are associated with high mortality rates. Currently, there are no effective anti-adenoviral therapies available. It is well known that actinobacteria can produce secondary metabolites that are attractive in drug discovery due to their structural diversity and their evolved interaction with biomolecules. Here, we have established an extract library derived from actinobacteria isolated from Vestfjorden, Norway, and performed a screening campaign to discover anti-adenoviral compounds. One extract with anti-adenoviral activity was found to contain a diastereomeric 1:1 mixture of the butenolide secondary alcohols 1a and 1b. By further cultivation and analysis, we could isolate 1a and 1b in different diastereomeric ratio. In addition, three more anti-adenoviral butenolides 2, 3 and 4 with differences in their side-chains were isolated. In this study, the anti-adenoviral activity of these compounds was characterized and substantial differences in the cytotoxic potential between the butenolide analogs were observed. The most potent butenolide analog 3 displayed an EC₅₀ value of 91 μM and no prominent cytotoxicity at 2 mM. Furthermore, we propose a biosynthetic pathway for these compounds based on their relative time of appearance and structure.  相似文献