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- Eliman, A., et al.
(författare)
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Totalparenteral nutrition after surgery rapidly increases serum leptin levels
- 2001
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Ingår i: European Journal of Endocrinology. - Bristol, NQ, USA : Bioscientifica. - 0804-4643 .- 1479-683X. ; 144:2, s. 123-128
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Tidskriftsartikel (refereegranskat)abstract
- Objective: In humans, leptin is regulated by long-term changes in energy intake. However, short-term regulation of serum leptin by nutrients has been difficult to show. The aim of this study was to investigate whether short periods of fasting and stress sensitise the leptin response to nutrients.Subjects and experimental protocol: Fourteen patients of normal weight undergoing elective open cholecystectomy were randomised into two groups. One group received saline infusion during surgery and for 24 h postoperatively. The other group also received saline during the surgical procedure, but total parenteral (TPN) was started immediately after surgery. Blood samples were drawn before as well as 2, 4, 8, 16, and 24 h after the start of surgery to determine the serum levels of leptin and other hormones.Results: Postoperative TPN induced a significant rise in serum leptin within 6 h, reaching a more than fourfold increase within 14 h (P < 0.001). Serum glucose and insulin levels increased within 2 h. Growth hormone and IGF-1 serum levels also increased significantly in the group receiving TPN. Serum cortisol levels increased postoperatively in both groups, which may explain why no significant reduction in serum leptin was observed in the group receiving saline. Free tri-iodothyronine (T3) decreased in both groups, while catecholamines were similar in the groups.Conclusion: During fasting and surgical stress, nutrients rapidly increased the serum leptin levels in humans in a manner similar to that previously reported in rodents. This may be mediated by increases in serum glucose, insulin and cortisol.
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| 3. |
- Hansson, Bengt, et al.
(författare)
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Avian genome evolution : insights from a linkage map of the blue tit (Cyanistes caeruleus)
- 2010
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Ingår i: Heredity. - : Springer Science and Business Media LLC. - 0018-067X .- 1365-2540. ; 104:1, s. 67-78
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Tidskriftsartikel (refereegranskat)abstract
- We provide a first-generation linkage map of the blue tit (Cyanistes caeruleus), a passerine within the previously genetically uncharacterized family Paridae, which includes 91 orthologous loci with a single anchored position in the chicken (Gallus gallus) sequence assembly. The map consists of 18 linkage groups and covers 935 cM. There was highly conserved synteny between blue tit and chicken with the exception of a split on chromosome 1, potential splits on chromosome 4 and the translocation of two markers from chromosome 2 and 3, respectively, to chromosome 5. Gene order was very well conserved for the majority of chromosomes, an exception being chromosome 1 where multiple rearrangements were detected. Similar results were obtained in a comparison to the zebra finch (Taeniopygia guttata) genome assembly. The recombination rate in females was slightly higher than in males, implying a moderate degree of heterochiasmy in the blue tit. The map distance of the blue tit was similar to 78% of that of the Wageningen chicken broiler population, and very similar to the Uppsala chicken mapping population, over homologous genome regions. Apart from providing insights into avian recombination and genome evolution, our blue tit linkage map forms a valuable genetic resource for ecological and evolutionary research in Paridae. Heredity (2010) 104, 67-78; doi:10.1038/hdy.2009.107; published online 26 August 2009
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| 4. |
- Hansson, Bengt, et al.
(författare)
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Pronounced Fixation, Strong Population Differentiation and Complex Population History in the Canary Islands Blue Tit Subspecies Complex
- 2014
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:2
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Tidskriftsartikel (refereegranskat)abstract
- Evolutionary molecular studies of island radiations may lead to insights in the role of vicariance, founder events, population size and drift in the processes of population differentiation. We evaluate the degree of population genetic differentiation and fixation of the Canary Islands blue tit subspecies complex using microsatellite markers and aim to get insights in the population history using coalescence based methods. The Canary Island populations were strongly genetically differentiated and had reduced diversity with pronounced fixation including many private alleles. In population structure models, the relationship between the central island populations (La Gomera, Tenerife and Gran Canaria) and El Hierro was difficult to disentangle whereas the two European populations showed consistent clustering, the two eastern islands (Fuerteventura and Lanzarote) and Morocco weak clustering, and La Palma a consistent unique lineage. Coalescence based models suggested that the European mainland forms an outgroup to the Afrocanarian population, a split between the western island group (La Palma and El Hierro) and the central island group, and recent splits between the three central islands, and between the two eastern islands and Morocco, respectively. It is clear that strong genetic drift and low level of concurrent gene flow among populations have shaped complex allelic patterns of fixation and skewed frequencies over the archipelago. However, understanding the population history remains challenging; in particular, the pattern of extreme divergence with low genetic diversity and yet unique genetic material in the Canary Island system requires an explanation. A potential scenario is population contractions of a historically large and genetically variable Afrocanarian population, with vicariance and drift following in the wake. The suggestion from sequence-based analyses of a Pleistocene extinction of a substantial part of North Africa and a Pleistocene/Holocene eastward re-colonisation of western North Africa from the Canaries remains possible.
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| 9. |
- Ljungqvist, Marcus, et al.
(författare)
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Do microsatellites reflect genome-wide genetic diversity in natural populations? A comment on Väli et al. (2008).
- 2010
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Ingår i: Molecular Ecology. - 0962-1083. ; 19, s. 851-855
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Tidskriftsartikel (refereegranskat)abstract
- Abstract A recent study by Väli et al. (2008) highlights that microsatellites will often provide a poor prediction of the genome-wide nucleotide diversity of wild populations, but does not fully explain why. To clarify and stress the importance of identity disequilibrium and marker variability for correlations between multilocus heterozygosity and genome-wide genetic variability, we performed a simple simulation with different types of markers, corresponding to microsatellites and SNPs, in populations with different inbreeding history. The importance of identity disequilibrium was apparent for both markers and there was a clear impact of marker variability.
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| 10. |
- Ljungqvist, Marcus
(författare)
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Have a fling with your neighbour, you might be less related.
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Major threats to biodiversity and ecosystem persistence are fragmentation of habitats and declining population sizes. For conservation biologists to understand the consequences of declining populations for the long term persistence and recovery of species worldwide, it is important to know and understand the underlying causes of potential threats, such as the depletion of genetic diversity, which is important for populations to be able to adapt and prevail in a changing environment. One of the major threats is the risk of inbreeding, which might decrease the genetic diversity substantially in a population. It has long been notoriously hard to collect good pedigree data in wild populations, but with the continuous development of molecular methods, it has become possible to estimate inbreeding by using molecular markers, such as microsatellites and single nucleotide polymorphism (SNPs). These estimates of inbreeding have proven to be immensely valuable when studies of the consequences of inbreeding are conducted, from studies of inbreeding avoidance behavior to population fragmentation, but also in speciation and evolution. In this monograph, a collection of studies show different applications of molecular estimates of inbreeding and also discuss the pros and cons with the different methods and analysis following the estimation. The studies cover genome evolution, inbreeding avoidance, speciation and island theories using manly the blue tit (Cyanistes caeruleus) as a study organism.
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