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101.
Erik Kristensen Mikael Hjorth Jensen Torben Kjær Andersen 《Journal of experimental marine biology and ecology》1985,85(1):75-91
The influence of Nereis virens Sars burrows on nitrification, denitrification and total nitrate reduction was assessed in poor (0.7% organic matter) and rich (2.0% organic matter) sediment from the estuary, Norsminde Fjord. The experiments were performed as assays of potential activity, since natural conditions proved impossible to simulate in the unpredictable burrow environment. The measurements were made in two microprofiles, extending 15 mm into the sediment from the surface and from the burrow wall lining. Both sediment types showed higher potential nitrification in the wall linings than in the surface sediment. This was positively correlated with the content of silt + clay particles and organic matter (i.e. the mucous lining of burrow walls). An elevated nitrate reduction activity was evident in the oxic layer of surface sediment. No such activity pattern was observed in the burrow walls. Denitrification accounted for 27–53 % of the total nitrate reduction. An empirical relationship between the ratio of predicted oxygen penetration into surface and wall sediment and the contribution of nereid burrows to bulk actual nitrification and nitrate reduction is presented. The burrow contribution to bulk nitrification was, in contrast to bulk nitrate reduction, very sensitive to variable oxygen penetrations. Thus, possible short-time changes in nitrate exchange across the wall lining will apparently be regulated by changes in nitrification activity rather than nitrate reduction activity. 相似文献
102.
Adaptive divergence despite strong genetic drift: genomic analysis of the evolutionary mechanisms causing genetic differentiation in the island fox (Urocyon littoralis)
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W. Chris Funk Robert E. Lovich Paul A. Hohenlohe Courtney A. Hofman Scott A. Morrison T. Scott Sillett Cameron K. Ghalambor Jesus E. Maldonado Torben C. Rick Mitch D. Day Nicholas R. Polato Sarah W. Fitzpatrick Timothy J. Coonan Kevin R. Crooks Adam Dillon David K. Garcelon Julie L. King Christina L. Boser Nicholas Gould William F. Andelt 《Molecular ecology》2016,25(10):2176-2194
The evolutionary mechanisms generating the tremendous biodiversity of islands have long fascinated evolutionary biologists. Genetic drift and divergent selection are predicted to be strong on islands and both could drive population divergence and speciation. Alternatively, strong genetic drift may preclude adaptation. We conducted a genomic analysis to test the roles of genetic drift and divergent selection in causing genetic differentiation among populations of the island fox (Urocyon littoralis). This species consists of six subspecies, each of which occupies a different California Channel Island. Analysis of 5293 SNP loci generated using Restriction‐site Associated DNA (RAD) sequencing found support for genetic drift as the dominant evolutionary mechanism driving population divergence among island fox populations. In particular, populations had exceptionally low genetic variation, small Ne (range = 2.1–89.7; median = 19.4), and significant genetic signatures of bottlenecks. Moreover, islands with the lowest genetic variation (and, by inference, the strongest historical genetic drift) were most genetically differentiated from mainland grey foxes, and vice versa, indicating genetic drift drives genome‐wide divergence. Nonetheless, outlier tests identified 3.6–6.6% of loci as high FST outliers, suggesting that despite strong genetic drift, divergent selection contributes to population divergence. Patterns of similarity among populations based on high FST outliers mirrored patterns based on morphology, providing additional evidence that outliers reflect adaptive divergence. Extremely low genetic variation and small Ne in some island fox populations, particularly on San Nicolas Island, suggest that they may be vulnerable to fixation of deleterious alleles, decreased fitness and reduced adaptive potential. 相似文献
103.
Vinay Kumar Workineh Torben Carys S. Kenway Faith R. Schiro Mahesh Mohan 《Journal of virology》2016,90(10):5003-5019
104.
105.
Bjarne Larsen Marian Ørgaard Torben Bo Toldam-Andersen Carsten Pedersen 《Molecular breeding : new strategies in plant improvement》2016,36(3):24
We present a new efficient screening tool for detection of S-alleles in apple. The protocol using general and multiplexed primers for PCR reaction and fragment detection on an automatized capillary DNA sequencer exposed a higher number of alleles than any previous studies. Analysis of alleles is made on basis of three individual fragment sizes making the allele interpretation highly accurate. The method was employed to genotype 432 Malus accessions and exposed 25 different S-alleles in a selection of Malus domestica cultivars of mainly Danish origin (402 accessions) as well as a selection of other Malus species (30 accessions). The allele S3 (28 %) was the most common among the Danish cultivars followed by S1 and S7 (both 27 %). The alleles S36 and S40 not previously reported from M. domestica were found in 6 and 17 cultivars, respectively. Complete allelic composition was found in 91 % of the 369 diploid accessions and in 86 % of the 63 triploids concerned. We further identified a relatively high frequency of S33 and S34, which has not been considered by most previous studies. The protocol presented here is easy to adopt and saves both time and work effort compared to previous methods. The robustness is illustrated by the great accuracy and a high number of S-alleles presented. 相似文献
106.
Mate choice screening in captive solitary carnivores: The role of male behavior and cues on mate preference and paternity in females of a model species,American mink (Neovison vison)
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107.
Effect of a nitrogen pulse on ecosystem N processing at different temperatures: A mesocosm experiment with 15NO3− addition
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Saara Olsen Yu Cao María Florencia Gutierrez Sandra Brucet Frank Landkildehus Torben L. Lauridsen Thomas A. Davidson Martin Søndergaard Erik Jeppesen Nils Risgaard‐Petersen 《Freshwater Biology》2017,62(7):1232-1243
- 相似文献
108.
Factors controlling the stable isotope composition and C:N ratio of seston and periphyton in shallow lake mesocosms with contrasting nutrient loadings and temperatures
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Carolina Trochine Marcelo Guerrieri Lone Liboriussen Priscila Willems Torben L. Lauridsen Martin Søndergaard Erik Jeppesen 《Freshwater Biology》2017,62(9):1596-1613
109.
Marie Krogh Nielsen Sven Magnus Hector Kelly Allen Yousif Subhi Torben Lykke Sørensen 《Immunity & ageing : I & A》2017,14(1):18
Background
Neutrophil dysfunction plays a key role in the development of diseases characterized by inflammation and angiogenesis. Here, we studied the systemic expression of neutrophil markers reflecting activation, adhesion, and resolution of inflammation in patients with neovascular age-related macular degeneration (AMD).Results
This was a prospective case-control study of patients with neovascular AMD and age-matched healthy control individuals. Patients were recruited from an outpatient program, and control individuals were recruited amongst patients’ relatives. Current smokers and individuals with either active immune-disease or ongoing cancer were not included, as these factors are known to affect neutrophil function. Fresh-drawn venous blood was processed for flow cytometric analysis of neutrophil markers. We determined percentages of positive cells and compared expression levels using fluorescence intensity measures. We found conditional differences on marker expression between patients with neovascular AMD (n = 29) and controls (n = 28): no differences were found when looking broadly, but several differences emerged when focusing on non-smokers. Here, patients with neovascular AMD had increased expression of the activity marker cluster of differentiation (CD) 66b (P = 0.003; Mann-Whitney U test), decreased expression of adhesion marker CD162 (P = 0.044; Mann-Whitney U test), and lower expression of the resolution of inflammation marker C-X-C chemokine receptor 2 (P = 0.044; Mann-Whitney U test).Conclusions
We present novel evidence suggesting that the activity of circulating neutrophils, sensitive to smoking, may differ in patients with neovascular AMD.110.