| 1. |
- Ekerljung, Marie
(författare)
-
Candidate gene effects on beef quality
- 2012
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The contribution of five candidate genes to the variation in meat tenderness, pH, colour, marbling and water holding capacity (WHC) was analysed in muscle samples from 243 young bulls of Angus, Charolais, Hereford, Limousin, or Simmental breed, raised in Swedish commercial herds. The animals were genotyped for single nucleotide polymorphisms (SNPs) in the genes encoding calpain 1 (CAPN1:c.947G>C), calpastatin, (CAST:c.155C>T), diacylglycerol O-acyltransferase 1 (DGAT1), leptin (UASMS2C>T) and stearoyl-CoA desaturase 1 (SCD1). The CAPN1:c.947G>C SNP showed associations with marbling and meat colour, and to some extent also tenderness. The CAST:c.155C>T T allele, which was the most common allele, showed a favourable association with Warner Bratzler shear force (WBSF) and compression tests. The K232A polymorphism at the DGAT1 gene was associated with level of beef marbling. An association was observed between UASMS2C>T and compression tests and meat colour. The SCD1 SNP was associated with variation in meat colour traits after 6 days with access to oxygen. There was no association of the tested SNPs with WHC traits and pH value. Our results show that gene effects are of importance for quality of meat from Swedish young bull of beef breed and Swedish beef can therefore be improved by including beef quality and DNA-tests in the breeding program. The CAST:c.155C>T SNP proved to be a good marker for tenderness in Swedish beef.
|
|
| 2. |
- Henriksson, Maria, 1979-
(författare)
-
Production and engineering of a xyloglucan endo-transglycosylase from Populus tremula x tremuloides
- 2007
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this work was to develop a production process for the enzyme xyloglucan endo-transglycosylase from Populus tremula x tremuloides (PttXET16-34). The natural transglycosylating activity of this enzyme has previously been employed in a XET-Technology. This chemo enzymatic method is useful for biomimetic modification of cellulose surfaces and holds great potential for industrial applications. Thus, it requires that the XET-enzyme can be produced in larger scale.This work also shows how the wildtype PttXET16-34 was modified into a glycosynthase. By mutation of the catalytic nucleophile into an alanine, glycine or serine residue, enzymes capable of synthesising defined xyloglucan fragments were obtained. These defined compounds are very valuable for further detailed studies of xyloglucan active-enzymes, but are also useful in molecular studies of the structurally important xyloglucan-cellulose interaction.A heterologous production system for PttXET16-34 was previously developed in the methylotrophic yeast Pichia pastoris. A methanol-limited fed-batch process was also previously established, but the yield of active XET was low due to proteolysis problems and low productivity. Therefore, two alternative fed-batch techniques were investigated for the production of PttXET16-34: a temperature-limited fed-batch (TLFB) and an oxygen-limited high-pressure fed-batch (OLHPFB).For the initial recovery of XET after the fermentation process, two different downstream processes were investigated: expanded bed adsorption (EBA) and cross-flow filtration (CFF).
|
|
| 3. |
- Bonow, Sandra
(författare)
-
Breeding of Swedish Warmblood horses towards specialization in show jumping and dressage
- 2023
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A clear specialization towards show jumping or dressage performance is evident in most European Warmblood studbooks. As a consequence, some breeding organizations have introduced specialized breeding programs. The aim of this thesis was to investigate the specialization towards show jumping and dressage in the Swedish Warmblood (SWB) population, as well as the relationships between linearly scored traits and performance in these disciplines. The proportion of allround horses had decreased considerably from 1980 in favor of show jumping and dressage horses. A decrease was also seen in the average relationship between show jumping and dressage horses over time, while it increased within the subpopulations during the past decade. A future scenario with discipline-specific young horse tests would result in decreased heritability and genetic variance for traits that are not assessed for all horses, but would have only minor impact on the ranking of sires within discipline based on breeding values. Phenotypic relationships between linearly scored traits and competition results showed that few traits except jumping traits were important for performance in show jumping, whereas several conformation and gait traits seemed to be of high importance for performance in dressage. For show jumping performance, most relationships had a linear association, whereas relationships with intermediate optimal scores were common for performance in dressage. The findings confirm the specialization of the SWB population, and that linear assessment of young horses is a valuable tool in sport horse breeding.
|
|
| 4. |
- Eken Asp, Helena
(författare)
-
Everyday behaviour in dogs : breed differences and genetic analysis
- 2015
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The absolute majority of dogs are kept as companion animals. Dogs kept as family pets are frequently exposed to noisy and crowded environments, and often have to interact with unfamiliar dogs and humans. In Sweden, we have a long history of recording behaviour in dogs on a large scale. The Swedish Working Dog Association (SBK) has, since 1989, carried out a standardized behavioural test called Dog Mentality Assessment (DMA). Results from the DMA can be condensed into five personality traits: playfulness, sociability, curiosity/fearlessness, chase-proneness and aggression. The aim of this thesis was to investigate the possibility to use information from the DMA to select for improved everyday life in dogs and to study the genetic background of everyday behaviour. This was done by estimating factors affecting everyday life behaviour as well as the genetic background of behaviour assessed either through a questionnaire or measured in the DMA. In the first study (I) we investigated factors affecting everyday behaviour in 20 dog breeds. The analysis was based on records from a total of 3,591 dogs. In the second study (II) we estimated genetic parameters for behaviour in the Rough Collie both for everyday behaviour assessed through a questionnaire and for behaviour assessed in the DMA. The analysis included records for 1,738 dogs on everyday behaviour and records for 2,953 dogs from the DMA. Results from the studies showed that age, sex, breed and breed group (working vs non-working breeds) had a significant effect on everyday behaviour. Working dog breeds were overall more interested in playing with humans and more trainable. Phenotypic correlations showed, for example, that more fearful dogs were more aggressive and dogs that were more eager to play with humans were easier to train. The estimated heritabilities for both everyday behaviour and DMA behaviour traits ranged between 0.06 and 0.36. The genetic correlations between everyday behaviour traits and DMA results indicate that the DMA could be used as an effective tool for selection of everyday behaviour in the Rough Collie.
|
|
| 5. |
- Loberg, Anne
(författare)
-
Genetic variance and covariance components for across population evaluation of Brown Swiss cattle
- 2015
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Dairy cattle breeding is an international business, with trade of animal material across populations. Interbull performs international genetic evaluations of dairy bulls, enabling fair comparisons across populations. The bull daughter performances differ between populations and international evaluations therefore require estimation of genetic correlations between the populations. Prerequisites for estimating correlations are knowledge about the genetic variances and covariances within and between populations and the relationship between the bulls. Traditionally, pedigree information has been used to build the relationship matrix connecting included bulls. The recent developments in DNA technology have made it possible to also build genomic relationship matrices using information from the bull genomes. The purpose of this thesis was to evaluate variances and covariances estimated using pedigree or genomic relationship matrices and the effect of factors such as trait heritability, population size, and number of bulls used in more than one population. Moreover, we evaluate the genetic correlations estimated using our different estimates. Genetic variance estimates were compared for a total of 175 population-trait combinations, and genetic covariance and correlation estimates were assessed for four populations and three traits. Phenotypes, genotypes and pedigree were available for 8 864 Brown Swiss bulls originating from Germany-Austria, France, Italy, Slovenia, Switzerland and the United States of America. The results showed that more genetic variance and covariance was explained when the pedigree relationship matrix was used than using the genomic relationship matrix. We found an effect of trait heritability and population size on the genetic variance estimates and an effect of number of common bulls on the genetic covariance estimates. The estimated genetic correlations were similar for both relationship matrices used in the estimation of variances and covariances, indicating that it should be possible to obtain accurate across-population correlation estimates using genomic relationship matrices.
|
|
| 6. |
- Mgbeahuruike, Anthony Christian
(författare)
-
A study of the traits associated with the biocontrol activity of Phlebiopsis gigantea
- 2009
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Phlebiopsis gigantea has routinely been used for the biocontrol of the conifer pathogen, Heterobasidion annosum s.l. but the mechanism for the biocontrol action has not been properly understood. In the present work, 64 isolates of P. gigantea were screened for traits important for the biocontrol of H. annosum. Growth rate and the interaction patterns of H. annosum s.l. and P.gigantea were studied in both carbon rich (Hagem) and low carbon media (Norkrans). Laccase assay and wood degradation capabilities were performed on the 64 isolates. Data was analyzed with multiple regression and principal component analysis. Results showed a significant effect of culture composition on the outcome of the interaction, 90 % of the isolates were able to displace H. annosum s.s. in sawdust media after 20 days, as compared with only 4% recorded in the glucose rich Hagem media. High growth rate on sawdust, a lignified carbon source, correlated with high growth rate in ferulic acid, a lignin precursor (P = 0.078), high growth rate in xylan, a hemicellulose (P = 0.001) and percentage weight loss in pine (P = 0.01). Interaction in sawdust correlated with high wood degradation capability in pine and spruce with P-values (P = 0.01, P = 0.03) respectively, high growth rate in xylan (P = 0.01), laccase production (P = 0.08), interaction in Hagem (P = 0.01) and mean growth rate at 10 °C (P = 0.001). Additionally, the role of hydrophobin in the competitive interaction was further investigated. The genomic sequence of Phlebiopsis gigantea hydrophobins 1 and 2 (Pgh1 and Pgh2) from a subset of isolates selected on the basis of geographical origins and antagonistic abilities was investigated. Similarly, the expression of Pgh1 and Pgh2 under different substrate conditions was also studied using quantitative PCR. Sequence analysis was performed with Clustal W and inspected with Megalign (DNA Star). Expression data was analyzed using the relative quantification method- 2-ΔΔCt and tested for effects of isolates, genes and culture conditions using the general linear model (GLM) procedure in SAS. There was a close sequence similarity between hydrophobin genes of isolates having different antagonistic capabilities and from different geographical sources. Higher transcript levels of Pgh1 and Pgh2 were recorded in submerged cultures compared with aerial conditions. The effect of substrate on the expression of the two genes (Pgh1 and Pgh2) was statistically significant (P = 0.0001). Differences in transcript levels of Pgh1 and Pgh2 were also observed among isolates belonging to different antagonistic categories. Overall, the results suggests that the antagonistic and competitive advantage of P. gigantea, hinged on the ability of the isolates to degrade the different structural components of wood. A significant correlation was also found between some high antagonistic isolates and the expression of hydrophobin genes (Pgh1 and Pgh2). The significance of these results in the biological control is discussed.
|
|
