Microalgae play a key function in aquatic ecosystems. Their development and growth are strongly regulated by trace metals as essential elements. However, trace metals could cause negative effects when exceeding certain concentrations in the environment. In this study we tested the development and growth rate of two freshwater microalgae, the cyanobacterium Pseudanabeana mucicola and the green alga Pediastrum duplex, from Vietnam over the period of 14 days exposing to chromium (Cr) at the concentrations up to 1,936 μg L-1. Besides, the Cr uptake and absorption by P. mucicola were evaluated over 7 days incubated in medium containing 422 μg Cr L-1. The results showed that Cr at the concentrations up to 1,078 μg L-1 did not inhibit the development and growth rate of P. mucicola. Similarly, concentration of 224 μg Cr L-1 had no adverse effects on growth of P. duplex. The cyanobacterium P. mucicola could make a reduction up to 71% of Cr in the test medium, hence become a distinguished candidate for metal phytoremediation. To the best of our knowledge this is the first investigation on the responses and absorption of Cr by freshwater microalgae from Vietnam. / Vi tảo đóng vai trò quan trọng trong hệ sinh thái thủy vực. Sự sinh trưởng và phát triển của chúng được điều tiết mạnh mẽ bởi kim loại vi lượng như những yếu tố thiết yếu. Tuy nhiên, những kim loại vi lượng này có thể gây ra những ảnh hưởng tiêu cực khi vượt quá nồng độ nhất định trong môi trường. Trong nghiên cứu này, chúng tôi thử nghiệm sự phát triển và tốc độ phát triển của hai loài vi tảo nước ngọt: loài tảo lam Pseudanabeana mucicola và loài tảo lục Pediastrum duplex có nguồn gốc từ Việt Nam trong thời gian 14 ngày phơi nhiễm với crôm (Cr) tại nồng độ lên tới 1.936 μg L-1. Bên cạnh đó, sự hấp thu Cr của P. mucicola cũng đã được đánh giá trong thời gian 7 ngày nuôi trong môi trường chứa 422 μg Cr L-1. Kết quả cho thấy Cr tại nồng độ lên tới 1.078 μg L-1 không kìm hãm sự phát triển và tốc độ sinh trưởng của P. mucicola. Tương tự, tại nồng độ 224 μg Cr L-1 không có bất kì ảnh hưởng tiêu cực đến sự phát triển của P. duplex. Loài tảo lam P. mucicola có thể làm giảm 71% hàm lượng Cr trong môi trường thí nghiệm, vì vậy được xem là ứng viên sáng giá cho quá trình xử lý môi trường ô nhiễm kim loại bằng thực vật . Theo hiểu biết của nhóm tác giả, đây là nghiên cứu đầu tiên về đáp ứng và hấp thu Cr bởi những vi tảo nước ngọt có nguồn gốc từ Việt Nam.

No description available.

Recent studies proposed that mammalian cell lines with slower growth rates were infected more efficiently by Trypanosoma cruzi, and that cell-to-cell transmission could be occurring during infection. This open the question of whether host cell-growth rate is a cellular characteristic influencing Trypanosoma cruzi invasion and infection. To prove if this was the case, the cell growth-rate was inhibited by starvation, reducing the foetal bovine serum concentration in the medium, and using a cell-cycle arresting drug, Baicalein. Then the percentage of infected cells of the control and the growth-modified group was measured via epifluorescence microscopy. The results did not show a strong evidence of negative correlation between the cell-growth rate and infection efficacy. To assess if cell-to-cell infection was occurring, the percentage of infected cells in contact with other infected cells was measured. This value was compared to the stochastic probability of this event happening. The results showed that the random probability of an infected cell being next to another infected cell was much lower than the percentage obtained from the empirical data. This suggests that cell-clusters found in infections are not a random event and that the dominant mechanism of infection is a short-range one: either by cell-to-cell infection, or by the proliferation of already infected cells. To support cell-to-cell transmission, parasites potentially passing from one cell to another were inspected through confocal microscopy and actin-rich regions were found at the parasite location. To determine whether actin played a role in this event, cells with a mutation in the actin gene were infected and compared to the mock group. The results showed that the percentage of infected cells in contact with other infected cells was lower for the mutant cells, suggesting that actin could play a key role in this event.

Sweetgum, Liquidambar styraciflua, is a diffuse-porous hardwood occurring in the southeastern United States. In this observational study, trees from two plantations of sweetgum were evaluated for mechanical properties. The two plantations were similar in age, soil type, competition control, and water availability, but differed in nutrient availability, growing season, and growth rate. Three trees representing different crown classes were removed from both plantations. Each tree was sampled for compression strength parallel to grain along the height of the merchantable stem. Oven-dry specific gravity was then calculated for each sample. The results indicate that young sweetgum trees grow weaker wood than mature trees. It was observed that dominant trees were stronger and denser than other trees. Denser wood was formed in the plantation with the shortest growing season and smallest growth rate. Three of six trees showed significant correlations of strength and stiffness with height in the tree. / Master of Science

Tesis por compendio / [EN] The aim of this thesis was to evaluate the productive performance of a rabbit line (OR-LS) selected by ovulation rate during first 6 generations (period 1), and later by ovulation rate (OR) and litter size (LS) during 11 generations using independent culling levels (Period 2). Genetic parameters, direct response for OR and LS and the correlated response for embryo (ES), foetal (FS) and prenatal survival (PS) were estimated. Also, the correlated response on growth rates (GR), weaning (WW) and marketing weight (MW) were estimated. The objective of chapter 3 was to estimate the genetic parameters of the productive traits and the response to selection by OR and LS of OR-LS line. For traits analysis, Bayesian methods were used. Heritability values of litter size traits were low, 0.10, 0.07, 0.07 and 0.07 for litter size, number of born alive (NBA), number of kits at weaning (NW) and marketing (NM), respectively. Heritability for OR was moderate (0.25), while it was low (0.13 and 0.14) for number of implanted embryos (IE) and number of live foetuses at 12 days of gestation (LF12), respectively. Low heritability values for survival traits were found, 0.09 for embryo survival (ES), 0.16 for foetal survival (FS) and 0.14 for prenatal survival (PS). In the second period, after 11 generations of selection by OR and LS, a genetic response of 0.17 kits per generation for LS was achieved. This response was higher than the obtained in period 1 (0.07 kits per generation), in which just selection by OR was performed. The opposite effect was found for OR; the highest response for OR appeared in the first period (0.24 ova per generation) versus the second period (0.17 ova per generation). This reduction in OR response can be due to the decrease in selection differential during the second period of selection. Since high genetic correlations were obtained for LS and other litter size traits, a positive correlated response was observed for NBA, NW and NM (0.12, 0.12 and 0.11 kits per generation, respectively) in the second period. In the first period, no correlated response on ES was observed and a decrease in FS (-0.04) was found. Nevertheless, in the second period a correlated response on PS appeared due to an improvement in both ES (0.04) and FS (0.03). Summarizing, the improvement in litter size in the second period is due to an increase in ovulation rate as well as an increase in prenatal survival. The objective of chapter 4 was to study the correlated response on growth traits in the OR-LS line in both periods of selection, the selection by OR during six generations and the selection by independent levels by OR and LS during 11 generations. The heritability estimates were low for weaning weight (WW), marketing weight (MW) and growth rate (GR), 0.09, 0.13 and 0.14, respectively. The estimated genetic correlations of WW, GR and MW with LS were around zero and with OR were positive and from low (0.19) to moderate (0.38). The positive moderate genetic correlation estimated between OR and MW could explain the correlated response found in MW. Correlated response on WW could be explained by positive and high genetic correlation between MW and WW. The aim of chapter 5 was to investigate magnitude and timing of embryo and early foetal survival in females with high OR using hormonal treatment as a model for selection by OR. Two groups of females (treated and untreated) were used. Treated females were injected with 50 IU eCG 48 hours before mating. Females were slaughtered at day 18 of gestation. OR, IE, LF12 and LF18 were recorded. Besides, ES (IE/OR), FSLF18 (LF18/IE), FSLF18/LF12 (LF18/LF12) and PSLF18 (LF18/OR) were estimated. Treated females had a higher OR than untreated females. According to the previous results for OR and LF18, treated females showed a lower survival rate from ovulation to 18 d of gestation. Treated females also had lower embryo and foetal survival. Main difference in foetal survival appeared from day 12 to 18 of gestation. / [ES] El objetivo de esta tesis fue evaluar el tamaño de camada de una línea de conejo seleccionada por tasa de ovulación durante las primeras seis generaciones (periodo 1) y después por tasa de ovulación (OR) y tamaño de camada (LS) durante 11 generaciones mediante el método de niveles independientes (periodo 2). Se estimaron los parámetros genéticos, así como la respuesta en OR y LS y la respuesta correlacionada en los caracteres reproductivos (capítulo 3). Además, se evaluó la respuesta correlacionada en los caracteres de crecimiento (capítulo 4); peso al destete (WW), peso al sacrificio (MW) y ganancia de peso entre el destete y el sacrificio (GR). Para el análisis de los caracteres se utilizaron métodos bayesianos. El objetivo del capítulo 3 fue estimar los parámetros genéticos de los caracteres reproductivos y la respuesta a la selección. Los valores de heredabilidad de los caracteres del tamaño de camada fueron bajos (alrededor de 0.10). La heredabilidad estimada para OR fue moderada (0.25), mientras que fue baja para el número de embriones implantados (IE) y el número de fetos vivos a los 12 días de gestación (LF12). Se obtuvieron valores bajos de heredabilidad; 0.09 para la supervivencia embrionaria (ES), 0.16 para la supervivencia fetal (FS) y 0.14 para la supervivencia prenatal (PS). En el periodo 2, se obtuvo una respuesta genética de 0.17 gazapos por generación para LS. Esta respuesta fue mayor que la obtenida en el periodo 1. En el caso de la tasa de ovulación, la mayor respuesta en OR se obtuvo en el periodo 1 (0.24 óvulos por generación) versus (0.17 óvulos por generación) en el periodo 2. Esta reducción en la respuesta de OR se puede atribuir a la disminución del diferencial de selección durante el período 2 de selección. De acuerdo con la alta correlación genética entre LS y otros caracteres del tamaño de camada, también se observó una respuesta correlacionada positiva en el número de nacidos vivos (NBA), destetados (NW) y comercializados (NM); 0.12, 0.12 y 0.11 gazapos por generación, respectivamente, en el segundo periodo. En el primer periodo no se observa respuesta correlacionada en la SE y se produce una disminución de la SF (-0.04). Sin embargo, en el segundo periodo se produce una respuesta correlacionada positiva en la SP que se debe a una mejora de la SE (0.04) y SF (0.03). En resumen, la mejora del tamaño de camada en el segundo periodo se debe tanto a un aumento de la tasa de ovulación como a un aumento de la supervivencia prenatal. El objetivo del capítulo 4 fue estudiar la respuesta correlacionada en los caracteres de crecimiento en esta línea. Las estimas de heredabilidad fueron bajas para los caracteres WW (0.09), MW (0.13) y GR (0.14). Las correlaciones genéticas estimadas de LS con WW, MW y GR fueron cercanas a cero; con la tasa de ovulación, las correlaciones fueron positivas y variaban de bajas a moderadas (de 0.19 a 0.38). La correlación genética moderada entre OR y MW podría explicar la respuesta correlacionada observada en MW. La alta correlación entre MW y WW podría explicar la respuesta correlacionada obtenida para WW. Finalmente, el objetivo de capítulo 5 fue estudiar en hembras con alta tasa de ovulación en qué momento se producen las mayores pérdidas fetales y cómo se ve afectado el desarrollo fetal. Para ello, de un total de 51 hembras, 24 hembras fueron pinchadas con 50 UI de eCG 48 horas antes de la cubrición para aumentar la tasa de ovulación. Las hembras fueron sacrificadas a los 18 días de gestación. Se registró OR, IE y el número de fetos vivos a los 12 y 18 días de gestación (LF18). Las hembras tratadas tuvieron una tasa de ovulación mayor que las no tratadas. De acuerdo con los resultados obtenidos para OR y LF18, las hembras tratadas mostraron una supervivencia más baja desde la ovulación hasta los 18 días de gestación y tuvieron una menor supervivencia embrionaria y fetal. Las principales diferencias en l / [CA] L'objectiu d'esta tesi va ser avaluar la millora de la grandària de ventrada d'una línia de conill seleccionada per tasa d'ovulació durant les primeres sis generacions (període 1) i després per tasa d'ovulació (OR) i la grandària de ventrada (LS) durant 11 generacions per mitjà del mètode de nivells independents (període 2). Es van estimar els paràmetres genètics, així com la resposta en OR i LS i la resposta correlacionada en caràcters reproductius (capítol 3). A més, es va estudiar la resposta correlacionada en els caràcters de creixement (capítol 4); pes al deslletament (WW), pes al sacrifici (MW) i guany de pes entre el deslletament y el sacrifici (GR). Per a l'anàlisi dels caràcters es van utilitzar mètodes bayesians. L'objectiu del capítol 3 va ser estimar els paràmetres genètics dels caràcters reproductius i la resposta a la selecció. Els valors d'heretabilitat dels caràcters de la grandària de ventrada van ser baixos (al voltant de 0.10). L'heretabilitat estimada per a OR va ser moderada (0.25), mentres que va ser baixa per al nombre d'embrions implantats (IE) i el nombre de fetus vius als 12 dies de gestació (LF12). Es van obtindre valors baixos d'heretabilitat; 0.09 per a ES, 0.16 per a FS i 0.14 per a PS. En el període 2, es va obtindre una resposta genètica de 0.17 llorigons per generació per a LS. Esta resposta va ser major que l'obtinguda en el període 1. En el cas de la tasa d'ovulació, la major resposta per a OR va ser en el primer període (0.24 òvuls per generació) versus (0.17 òvuls per generació) en el període 2. Esta reducció en la resposta d'OR es pot atribuir a la disminució del diferencial de selecció durant el període 2 de selecció. Donada l'alta correlació genètica entre LS i altres caràcters de la grandària de ventrada, també es va observar una resposta correlacionada positiva en el nombre de nascuts vius (NBA), deslletats (NW) i comercialitzats (NM); 0.12, 0.12 i 0.11 llorigons per generació, respectivament, en el segon període. En el primer període no s'observa resposta correlacionada en la SE i es produeix una disminució de la SF (-0.04). No obstant això, en el segon període es produeix una resposta correlacionada en la SP que es deu a una millora de la SE (0.04) i SF (0.03). En resum, la millora de la grandària de ventrada en el segon període es deu tant a un augment de la tasa d'ovulació com a un augment de la supervivència prenatal. L'objectiu del capítol 4 va ser estudiar la resposta correlacionada en els caràcters de creixement en aquesta línia. Les estimes d'heretabilitat van ser baixes per als caràcters WW (0.09), MW (0.13) i GR (0.14). Les correlacions genètiques estimades de LS amb WW, MW i GR van ser pròximes a zero; amb la tasa d'ovulació, les correlacions van ser positives i variaven de baixes a moderades (de 0.19 a 0.38). La correlació genètica moderada entre OR i MW podria explicar la resposta correlacionada trobada per a MW. D'altra banda, l'alta correlació entre MW i WW podria explicar la resposta correlacionada obtinguda per a WW. Finalment. l'objectiu del capítol 5 va ser estudiar en femelles amb alta tasa d'ovulació en quin moment es van produir les majors pèrdues fetals i com es veu afectat el desenvolupament fetal. Per a això, d'un total de 51 femelles, 24 femelles van ser punxades amb 50 UI d'eCG 48 hores abans del cobriment per a augmentar la tasa d'ovulació. Les femelles van ser sacrificades al 18 dies de gestació. Es va registrar OR, IE i el nombre de fetus vius al 12 i 18 dies de gestació (LF18). Les femelles tractades van tindre una tasa d'ovulació major que les no tractades. D¿acord als resultats obtinguts per OR i LF18, les femelles tractades van mostrar una supervivència més baixa des de l'ovulació fins als 18 dies de gestació i van tindre una menor supervivència embrionària i fetal. Les principals diferències en la supervivència fetal van aparèixer entre els dies 12 i 18 de gestaci / Yehia Badawy Elmoghazy, A. (2016). SELECTION FOR OVULATION RATE AND LITTER SIZE IN RABBITS [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/73265 / Compendio

Fiskar kan drabbas av många olika parasiter tillhörande ett brett spektrum av organismgrupper. Parasiter kan påverka värdens fysiologi, morfologi och beteende, vilket kan ha negativa effekter på värden.  Den starkt hotade flodpärlmusslan (Margaritifera margaritifera) parasiterar under sitt tidiga liv som glochidielarver på fiskgälar, i Sverige främst på öringen (Salmo trutta). I tidigare studier har man sett såväl negativa som inga effekter av parasiteringen på värdfisken. Syftet med min studie var att undersöka effekten av musslans parasitering på öringens rörelse, habitatval och tillväxt i Älgån i Arvika kommun, Värmland. Resultaten visade att höginfekterad öring förflyttade sig längre sträckor och hade lägre tillväxt än låginfekterad öring. Det var ingen skillnad mellan hög- och låginfekterade öringars habitatval med avseende på djup, vattenhastighet eller substrat. Sammanfattningsvis kan höginfekterade öringar ha högre mortalitetsrisk än låginfekterade, lägre tillväxt och sämre konkurrensförmåga, vilket kan ha negativa konsekvenser för musslans rekryteringsframgång. / Fish are affected by various parasites, belonging to many different taxonomic groups. Parasites can affect the host’s physiology, morphology, and behaviour, which may have negative effects for the host. The critically endangered freshwater pearl mussel (Margaritifera margaritifera) lives parasitically as glochidia larvae on the gills of fish, and in Sweden this occurs mainly in the gills of brown trout (Salmo trutta). During their parasitic stage, which lasts for almost one year, the mussel grows up to four or five times their initial size.  Previous studies have reported both negative and no effects of the parasite on the host fish. The aim of my study was to analyse the effect of the freshwater pearl mussel parasitation on the brown trout’s movement, habitat choice, and growth in the stream Älgån in Arvika municipalty, Värmland. The results show that highly infected brown trout moved greater distances and had lower growth than less infected trout. There was no difference in habitat choice in terms of depth, velocity, or substrate between high or low infected trout. In summary, highly infected trout may have high energy costs, low growth, and poor competitive ability, which can have negative consequences for the mussel’s recruitment.

The global increasing problem of antibiotic resistance necessarily drives the pursuit and discovery of new antimicrobial agents. Antimicrobial peptides (AMPs) initially seemed like promising new drug candidates. Already members of the innate immune system, it was assumed that they would be bioactive and non-toxic. Their common trait for fundamental, non-specific mode of action also seemed likely to reduce resistance development. In this thesis, we demonstrate the ease with which two species of pathogenic bacteria, the gram-negative Salmonella typhimurium (S. typhimurium), and the gram-positive Staphylococcus aureus (S. aureus), can gain increased tolerance and stable resistance to various AMPs. By serially passaging each bacterial species separately under increasing AMP selection pressure we observed increasing AMP tolerance. Resulting in independent bacterial lineages exposed to four different AMPs (including a two-AMP combination) that exhibited 2 to 16-fold increases in MIC. Substantial cross-resistance between the AMPs was observed. Additionally, the S. aureus mutants were found to be cross-resistant to human beta-defensins 1, 2, 3, and 4. The LPS molecule, with mutations in the waaY, pmrB and phoP genes, was the principal target for S. typhimurium resistance development. The main target for S. aureus remained elusive. Reduced membrane potential was a common change for two of the mutants, but not for the others. All sequenced mutants had one or more mutations in various stress response pathways. Fitness of the resistant mutants was assayed by growth rate analysis and in vitro virulence factor testing (e.g. survival response to bile, superoxide, acidic pH). Furthermore an in vivo survival/virulence test involving a mouse competition experiment (S. typhimurium) and sepsis model (S. aureus) was performed. In the absence of AMPs there was often little or no fitness reduction in the mutants. Our results suggest that AMP resistance mechanisms do not irrevocably weaken either species with regard to virulence characteristics or survival within the host. In light of these findings, we suggest that the progression of therapeutic use of AMPs should proceed with great caution since otherwise we might select for AMP resistant mutants that are more resistant to our innate host defenses and thereby potentially more virulent.

The main objective of the project was to establish a fracture-mechanics energy-based approach for the design of structural adhesive joints under cyclic loading. This required understanding how an adhesive system behaved near its fatigue threshold, and how the key factors affected this behavior in a fresh undegraded joint. The investigated factors were mode ratio (phase angle), substrate material, surface treatment and surface roughness (both affecting the bond strength), bondline thickness and load ratio. It was first required to understand how the adhesive system behaved under quasi-static loading by examining a fracture mechanics-based design approach for adhesive systems with different substrate materials and geometries. Experiments were initially performed to characterize the strength of aluminum and steel adhesive systems based on the fracture envelope, critical strain energy release rate as a function of the mode ratio. Ultimate failure loads of aluminum and steel adhesive joints, having different overlap end conditions and different geometries were then experimentally measured. These values were compared with the failure loads extracted from the fracture envelope. Considering the toughening behavior of the adhesive in the fracture mechanics analyses, a very good agreement (average of 6%) was achieved between the predictions and experiments for all types of overlap end conditions and geometries. Different fatigue threshold testing approaches, which are commonly used in the literature or suggested by the ASTM standard, were evaluated for the cracked and intact fillet joints. Based on the experimental and analytical studies, the most appropriate technique for fatigue testing and characterization of adhesive systems was suggested. Comparing the mixed-mode near-threshold behavior of different adhesive systems with the fracture behavior and fatigue mode-I and mixed-mode high crack growth rates showed the high sensitivity of the mixed-mode near-threshold fatigue to the subtle changes in the interfacial bond strength. In order to make a baseline for the design of adhesive joints under cyclic loading, similar to the previous fracture tests and following the energy-based approach, fatigue behavior was characterized as a function of the loading mode ratio for aluminum and steel adhesive joints. The effect of substrate material, surface treatment, bondline thickness, surface roughness and fatigue testing load ratio on the near-threshold fatigue behavior of adhesives joints was evaluated experimentally. The experimental observations were then explained using finite element modeling. To generalize the conclusions, the majority of experiments and studies covered a broad range of crack growth rates, as low as fatigue threshold and as high as 10-2 mm/cycle. Having understood the significant testing and design parameters, an adhesive system can be designed based on a safe cyclic load that produces an insignificant (for automotive industry) or reasonably low but known crack growth rate (for aerospace industry).

The research assessed the potential of developing a selective breeding programme for the UK rainbow trout industry. Levels of genetic variation at 12 microsatellite loci were first compared in seven different commercial strains. The Observed heterozygosity ranged from Ho = 48.1% in a gold rainbow trout strain (GTR) to Ho = 66.4% in a newly derived broodstock population constructed from a number of different sources (GIT). The Expected Heterozygosity (He) was highest in GIM1 (He= 79.5%) and lowest in the GTR strain (He = 56.9%). The Effective number of alleles (Mae) showed that the GIM1, GIM2, GIM3, and GIT strain (5.4; 5.2; 4.8; 4.2) were significantly more variable than the other strains and that GTR strain had the lowest value (2.5). There appears to be substantial genetic variability within the commercial United Kingdom rainbow trout strains surveyed in this study. This appears to be the case despite very different management histories and levels of record keeping. The strains appear to be genetically distinct (based on population genetic analyses), though the reasons for this remain unclear (and possibly unanswerable given the poor records kept by the different companies). The Glenwyllin farm strains (GIM) were chosen to form the base population for the project because of their high genetic variability, disease free status and because the farm produced around 20 million ova per year, so any genetic gains would have a widespread impact. The farm has an early (Strain A) and a late spawning (Strain B) and these were mated in a partial factorial design, 20 females and 20 neomales per strain (A & B) were chosen on the basis of maturity and gamete quality in November 2002 so that each male was crossed to 4 females (2 in the same strain and 2 in the other), a total of 160 families were created. All broodstock were biopsied to enable them to be genotyped. The families were reared separately up to the eyed stage at which point the eggs from each family were divided into three to generate three communal replicate populations. One of these was sent to a fingerling producer (Iwerne Spring) for ongrowing to fingerling size and formed the basis of a commercial production trial at Test Valley Trout farm (TVT) in Hampshire. When the fish reached an average weight of 5 g they were transferred from Iwerne Spring to TVT and 1500 were randomly selected, PIT tagged and biopsied to enable them to be assigned to their family using 11 multiplexed microsatellite loci. Parental assignment was based on exclusion (FAP) but the results were compared with another parental assignment based on likelihood (PAPA). Of the 1500 offspring (OIM) PIT tagged 1242 82.8% could be assigned to a single family utilizing different combinations of more than 6 loci (6 to 11). The growth of the 1500 OIM fish was tracked throughout the grow out period before they were finally harvested and fully processed. The results of OIM strain at the end of the trial period were mean weight of 415.5 g, and a mean length of 314.5 mm. The visual measurement of colour gave a mean flesh colour values of 26.01 on the 20-34 scale (SalmoFan™), and 11.0 with the colotimetry evaluation of colour (a*). The heritability results for the IOM strain were 43 ± 9% for weight, 42 ± 9% for gutted, and 28 ± 8% for length. The heritability estimates for the visual colour variables were 19 ± 7% and when using the colorimeter, the red chromaticity (a*) heritability was 14 ± 6%. Therefore, the heritability results of the IOM strain indicate that there are opportunities of substantial and rapid improvement of the growth rate and flesh colour traits. Also no line effects were observed or indications of non-additive genetic variation. In contrast to these last results, the overall survival of the GIM strain from the time of the physical tagging with PIT until harvest was 52.8%, and survival heritability was extremely low, 3 ± 2%, hardly significant.

Understanding how temperature affects biological systems is a central question in ecology and evolutionary biology. Anthropogenic climate change adds urgency to this topic, as the demise or success of species under climate change is expected to depend on how temperature affects important aspects of organismal performance, such as growth, development, survival and reproduction. Rates of biological processes generally increase with increasing temperature up to some maximal temperature. Variation in the slope of the initial, rising phase has attracted considerable interest and forms the focus of this thesis. I explore variation in growth rate-temperature relationships over several levels of biological organization, both between and within species, over individuals’ lifetime, depending on the ecological context and in relation to important life history characteristics such as generation length and winter dormancy.       Specifically, I examine how a clade of temperate damselflies have adapted to their thermal environment along a 3,600 km long latitudinal transect spanning from Southern Spain to Northern Sweden. For each of six species, I sampled populations from close to the northern and southern range margin, as well from the center of the latitudinal range. I reared larvae in the laboratory at several temperatures in order to measure indiviudal growth rates. Very few studies of thermal adaptation have employed such an extensive sampling approach, and my finding reveal variation in temperature responses at several levels of organization.       My main finding was that temperature responses became steeper with increasing latitude, both between species but also between latitudinal populations of the same species. Additional genetic studies revealed that this trend was maintained despite strong gene flow. I highlight the need to use more refined characterizations of latitudinal temperature clines in order to explain these findings. I also show that species differ in their ability to acclimate to novel conditions during ontogeny, and propose that this may reflect a cost-benefit trade-off driven by whether seasonal transitions occur rapidly or gradually during ontogeny.       I also carried out a microcosm experiment, where two of the six species were reared either separately or together, to determine the interacting effects of temperature and competition on larval growth rates and population size structure. The results revealed that the effects of competition can be strong enough to completely overcome the rate-depressing effects of low temperatures. I also found that competition had stronger effects on the amount of variation in growth rates than on the average value.       In summary, my thesis offers several novel insights into how temperature affects biological systems, from individuals to populations and across species’ ranges. I also show how it is possible to refine our hypotheses about thermal adaptation by considering the interacting effects of ecology, life history and environmental variation.