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Marianne Andresen Dorte Bodin Dresbøll Lars Stoumann Jensen Jakob Magid Kristian Thorup-Kristensen 《Plant and Soil》2016,408(1-2):255-270
Background and aims
A study was made to quantify early root development, soil exploitation and nutrient uptake in spring wheat, onion and lettuce, and their variation among cultivars. The goal was to study genetic variation in root traits making cultivars better adapted to organic production systems or other low-input systems.Methods
Six cultivars of each species were grown in transparent tubes to allow direct observation of early root growth. The tubes were 0.3 m deep, and 0.24 m in diameter. By placing the plants close to the edge rather than at the centre of the tubes, we could quantify the spatial distribution of the root systems as well as the general root growth and nutrient uptake.Results
Root growth of wheat and lettuce was faster than root growth of onion, and onion showed little capacity for horizontal root system development. Significant variation in early root growth and horizontal spread of the root system was found among cultivars of all three species. In general, cultivars with strong growth and high volume of soil exploitation showed higher average nutrient concentrations.Conclusion
Early shoot growth, root growth and nutrient uptake are intrinsically linked, making it difficult to determine whether improved root growth was the primary cause of improved performance. However, we did find cultivars where the strong root growth and superior root distribution seemed to be the driver for improved overall growth.54.
Genetic diversity of Saccharina latissima (Phaeophyceae) along a salinity gradient in the North Sea–Baltic Sea transition zone 下载免费PDF全文
Mette Møller Nielsen Cristina Paulino João Neiva Dorte Krause‐Jensen Annette Bruhn Ester A. Serrão 《Journal of phycology》2016,52(4):523-531
The North Sea–Baltic Sea transition zone constitutes a boundary area for the kelp species Saccharina latissima due to a strong salinity gradient operating in the area. Furthermore, the existence of S. latissima there, along Danish waters, is fairly patchy as hard bottom is scarce. In this study, patterns of genetic diversity of S. latissima populations were evaluated along the salinity gradient area of Danish waters (here designated brackish) and were compared to reference sites (here designated marine) outside the gradient area, using microsatellite markers. The results showed that the S. latissima populations were structured into two clusters corresponding to brackish versus marine sites, and that gene flow was reduced both between clusters and between populations within clusters. In addition, results provided empirical evidence that marginal populations of S. latissima in the salinity gradient area exhibited a distinct genetic structure when compared to marine ones. Brackish populations were less diverse, more related, and showed increased differentiation over distance compared to marine populations. The isolation of the brackish S. latissima populations within the salinity gradient area of Danish waters in conjunction with their general low genetic diversity makes these populations vulnerable to ongoing environmental and climate change, predicted to result in declining salinity in the Baltic Sea area that may alter the future distribution and performance of S. latissima in the area. 相似文献
55.
Mogens?FengerEmail author Dorte?Lindqvist?Hansen Dorte?Worm Lisbeth?Hvolris Viggo?B.?Kristiansen Elin?Rebecka?Carlsson Sten?Madsbad 《BMC endocrine disorders》2016,16(1):59
Background
Roux-en-Y gastric bypass surgery is widely applied to ameliorate morbid obesity, including diabetes in people with type 2 diabetes. The latter vanish a few days after surgery for many, but not in all patients before any weight reduction has occurred. The explanation for this change in metabolic status is poorly understood, but the observation may suggest that the fate obesity and diabetes is only partly linked after surgery.Methods
The trajectories of weight reduction measured as reduced body mass index (BMI) in 741obese subjects with and without diabetes were evaluated. Evaluation was performed on three groups: 1) subjects that were non-diabetic before and after surgery; 2) subjects that were diabetics before surgery but non-diabetics after surgery; and 3) subjects that were diabetics before surgery and remained diabetics after surgery. The diabetic state was established at HbA1c above 48 mmol/mol.Results
The trajectories differ significantly between groups and any sub-populations of groups, the latter identified by the distance between individual trajectories using a k-means procedure. The results suggest that different domains in the enormous genetic network governing basic metabolism are perturbed in obesity and diabetes, and in fact some of the patients are affected by two distinct diseases: obesity and diabetes mellitus type 2.Conclusion
Although RYGB “normalized” many glycaemic parameters in some of the diabetic subjects apparently converting to a non-diabetics state, other diabetic subjects stay diabetic in the context of the new gut anatomy after surgery. Thus, the obesity part of the glycaemic derangement may have been ameliorated, but some defects of the diabetic state had not.56.
The Agrobacterium rhizogenes pRi TL-DNA segment as a gene vector system for transformation of plants
Jens Stougaard Dorte Abildsten Kjeld A. Marcker 《Molecular & general genetics : MGG》1987,207(2-3):251-255
Summary A plant gene transfer system was developed from the Agrobacterium rhizogenes pRi15834 TL-DNA region. Intermediate integration vectors constructed from ColE1-derived plasmids served as cloning vectors in Escherichia coli and formed cointegrates into the TL-DNA after transfer to A. rhizogenes. An A. rhizogenes strain with pBR322 plasmid sequences replacing part of the TL-DNA was also constructed. Plasmids unable to replicate in Agrobacterium can integrate into this TL-DNA by homologous recombination through pBR322 sequences. No loss of pathogenicity was observed with the strains formed after integration of intermediate vectors or strains carrying pBR322 in the TL-DNA segment. Up to 15 kb of DNA have been transferred to plant cells with these systems. The T-DNA from a binary vector was cotransformed into hairy roots which developed after transfer of the wild-type pRi T-DNA. Tested on Lotus corniculatus the TL-derived vector system transformed 90% of the developed roots and the T-DNA from the binary vector was cotransformed into 60% of the roots. Minimum copy numbers of one to five were found. Both constitutive and organ-specific plant genes were faithfully expressed after transfer to the legume L. corniculatus. 相似文献
57.
Volatile Fatty Acids and Hydrogen as Substrates for Sulfate-Reducing Bacteria in Anaerobic Marine Sediment 总被引:34,自引:23,他引:11 下载免费PDF全文
The addition of 20 mM MoO42− (molybdate) to a reduced marine sediment completely inhibited the SO42− reduction activity by about 50 nmol g−1 h−1 (wet sediment). Acetate accumulated at a constant rate of about 25 nmol g−1 h−1 immediately after MoO42− addition and gave a measure of the preceding utilization rate of acetate by the SO42−-reducing bacteria. Similarly, propionate and butyrate (including isobutyrate) accumulated at constant rates of 3 to 7 and 2 to 4 nmol g−1 h−1, respectively. The rate of H2 accumulation was variable, and a range of 0 to 16 nmol g−1 h−1 was recorded. An immediate increase of the methanogenic activity by 2 to 3 nmol g−1 h−1 was apparently due to a release of the competition for H2 by the absence of SO42− reduction. If propionate and butyrate were completely oxidized by the SO42−-reducing bacteria, the stoichiometry of the reactions would indicate that H2, acetate, propionate, and butyrate account for 5 to 10, 40 to 50, 10 to 20, and 10 to 20%, respectively, of the electron donors for the SO42−-reducing bacteria. If the oxidations were incomplete, however, the contributions by propionate and butyrate would only be 5 to 10% each, and the acetate could account for as much as two-thirds of the SO42− reduction. The presence of MoO42− seemed not to affect the fermentative and methanogenic activities; an MoO42− inhibition technique seems promising in the search for the natural substrates of SO42− reduction in sediments. 相似文献
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Vinni Mona Hansen Hanne Rosenquist Dorte Lau Baggesen Stanley Brown Bjarke Bak Christensen 《BMC microbiology》2007,7(1):90
Background
The predominant food borne pathogen in the western world today is Campylobacter. Campylobacter specific bacteriophages (phages) have been proposed as an alternative agent for reducing the burden of Campylobacter in broilers. One concern in relation to phage biocontrol is the narrow host range often displayed by phages. To identify the potential of phages as a Campylobacter reducing agent we needed to determine their infectivity on a panel of isolates representing the Campylobacter strains found in broilers as well as humans. 相似文献60.
Huber RC Remuge L Carlisle A Lillico S Sandøe P Sørensen DB Whitelaw CB Olsson IA 《Transgenic research》2012,21(4):773-784
Since large animal transgenesis has been successfully attempted for the first time about 25 years ago, the technology has been applied in various lines of transgenic pigs. Nevertheless one of the concerns with the technology--animal welfare--has not been approached through systematic assessment and statements regarding the welfare of transgenic pigs have been based on anecdotal observations during early stages of transgenic programs. The main aim of the present study was therefore to perform an extensive welfare assessment comparing heterozygous transgenic animals expressing GFP with wildtype animals along various stages of post natal development. The protocol used covered reproductory performance and behaviour in GFP and wildtype sows and general health and development, social behaviour, exploratory behaviour and emotionality in GFP and wildtype littermates from birth until an age of roughly 4 months. The absence of significant differences between GFP and wildtype animals in the parameters observed suggests that the transgenic animals in question are unlikely to suffer from deleterious effects of transgene expression on their welfare and thus support existing anecdotal observations of pigs expressing GFP as healthy. Although the results are not surprising in the light of previous experience, they give a more solid fundament to the evaluation of GFP expression as being relatively non-invasive in pigs. The present study may furthermore serve as starting point for researchers aiming at a systematic characterization of welfare relevant effects in the line of transgenic pigs they are working with. 相似文献