Browsing by Subject "Animals"

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  • Saari, Sini; Kemppainen, Esa; Tuomela, Tero; Oliveira, M.T.; Dufour, E.; Jacobs, H.T. (2019)
    The mitochondrial alternative oxidase, AOX, present in most eukaryotes apart from vertebrates and insects, catalyzes the direct oxidation of ubiquinol by oxygen, by-passing the terminal proton-motive steps of the respiratory chain. Its physiological role is not fully understood, but it is proposed to buffer stresses in the respiratory chain similar to those encountered in mitochondrial diseases in humans. Previously, we found that the ubiquitous expression of AOX from Ciona intestinalis in Drosophila perturbs the development of flies cultured under low-nutrient conditions (media containing only glucose and yeast). Here we tested the effects of a wide range of nutritional supplements on Drosophila development, to gain insight into the physiological mechanism underlying this developmental failure. On low-nutrient medium, larvae contained decreased amounts of triglycerides, lactate, and pyruvate, irrespective of AOX expression. Complex food supplements, including treacle (molasses), restored normal development to AOX-expressing flies, but many individual additives did not. Inhibition of AOX by treacle extract was excluded as a mechanism, since the supplement did not alter the enzymatic activity of AOX in vitro. Furthermore, antibiotics did not influence the organismal phenotype, indicating that commensal microbes were not involved. Fractionation of treacle identified a water-soluble fraction with low solubility in ethanol, rich in lactate and tricarboxylic acid cycle intermediates, which contained the critical activity. We propose that the partial activation of AOX during metamorphosis impairs the efficient use of stored metabolites, resulting in developmental failure. © 2019 The Authors. Journal of Experimental Zoology Part A: Ecological Genetics and Physiology Published by Wiley Periodicals, Inc.
  • Holma-Suutari, A.; Ruokojärvi, P.; Komarov, A.A.; Makarov, D.A.; Ovcharenko, V.V.; Panin, A.N.; Kiviranta, H.; Laaksonen, S.; Nieminen, M.; Viluksela, M.; Hallikainen, A. (Springer, 2016)
    Background: The Finnish and Russian animal species (semi-domesticated reindeer, Finnish wild moose, Baltic grey seal and Baltic herring) samples were biomonitored in terrestrial and aquatic environments for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polybrominated diphenylethers (PBDEs). Results: Grey seal (Halichoerus grypus) was clearly the most contaminated species. The mean PBDE concentration in grey seal was 115 ng/g fat, and the highest WHO-PCDD/F-PCB-TEQ (toxic equivalent set by WHO) was 327 pg/g fat. In Finnish, reindeer WHO-PCDD/F-TEQ varied from 0.92 pg/g fat in muscle to 90.8 pg/g fat in liver. WHO-PCDD/F-TEQ in moose liver samples was in the range of 0.7–4.26 pg/g fat, and WHO-PCB-TEQ in the range of 0.42–3.34 pg/g fat. Overall moose had clearly lower PCDD/F and DL-PCB concentrations in their liver than reindeer. Conclusions: Terrestrial animals generally had low POP concentrations, but in reindeer liver dioxin levels were quite high. All Finnish and Russian reindeer liver.
  • Haahtela, Tari (2016)
  • Kokko, Hanna; Jennions, Michael D; Houde, Anne (2007)
    The diversity of sexual traits favoured by females is enormous and, curiously, includes preferences for males with rare or novel phenotypes. We modelled the evolution of a preference for rarity that yielded two surprising results. First, a Fisherian 'sexy son' effect can boost female preferences to a frequency well above that predicted by mutation-selection balance, even if there are significant mortality costs for females. Preferences do not reach fixation, however, as they are subject to frequency-dependent selection: if choosy females are too common, then rare genotypes in one generation become common, and thus unattractive, in the offspring generation. Nevertheless, even at relatively low frequency, preferences maintain polymorphism in male traits. The second unexpected result is that the preferences can evolve to much higher frequencies if choice is hindered, such that females cannot always express their preferences. Our results emphasize the need to consider feedback where preferences determine the dynamics of male genotypes and vice versa. They also highlight the similarity between the arbitrariness of behavioural norms in models of social evolution with punishment (the so-called 'folk theorem') and the diversity of sexual traits that can be preferred simply because deviating from the norm produces unattractive offspring and is, in this sense, 'punished'.
  • Ovaskainen, Otso; Hanski, Ilkka (2004)
    Spatially structured populations in patchy habitats show much variation in migration rate, from patchy populations in which individuals move repeatedly among habitat patches to classic metapopulations with infrequent migration among discrete populations. To establish a common framework for population dynamics in patchy habitats, we describe an individual-based model (IBM) involving a diffusion approximation of correlated random walk of individual movements. As an example, we apply the model to the Glanville fritillary butterfly (Melitaea cinxia) inhabiting a highly fragmented landscape. We derive stochastic patch occupancy model (SPOM) approximations for the IBMs assuming pure demographic stochasticity, uncorrelated environmental stochasticity, or completely correlated environmental stochasticity in local dynamics. Using realistic parameter values for the Glanville fritillary, we show that the SPOMs mimic the behavior of the IBMs well. The SPOMs derived from IBMs have parameters that relate directly to the life history and behavior of individuals, which is an advantage for model interpretation and parameter estimation. The modeling approach that we describe here provides a unified framework for patchy populations with much movements among habitat patches and classic metapopulations with infrequent movements.
  • Balic, A. (Humana press, 2019)
    Methods in Molecular Biology
    Continuous growth of the rodent incisor is enabled by epithelial and mesenchymal stem cells (ESCs and MSCs) which unceasingly replenish enamel and dentin, respectively, that wear by persistent animal gnawing. Lineage tracing studies have provided evidence that ESCs contribute to all epithelial lineages of the tooth in vivo. Meanwhile, in the mouse incisor, MSCs continuously contribute to odontoblast lineage and tooth growth. However, in vitro manipulation of ESCs has shown little progress, mainly due to lack of appropriate protocol to successfully isolate, culture, expand, and differentiate ESCs in vitro without using the co-culture system. In this chapter we describe the isolation of the Sox2-GFP+ cell population that is highly enriched in ESCs. Isolated cells can be used for various types of analyses, including in vitro culture, single cell-related analyses, etc. Furthermore, we describe ways to obtain populations enriched in the incisor MSCs using FACS sorting of antibody-labeled cells. Easily accessible FACS sorting enables easy and relatively fast isolation of the cells labeled by the fluorescent protein. © Springer Science+Business Media, LLC, part of Springer Nature 2019.
  • Muha, Villo; Williamson, Ritchie; Hills, Rachel; McNeilly, A.D.; McWilliams, T.G.; Alonso, Jana; Schimpl, Marianne; Leney, Aneika C.; Heck, Albert J.R.; Sutherland, Calum; Read, Kevin D.; McCrimmon, Rory J.; Brooks, S.P.; Van Aalten, Daan M.F. (2019)
    O-GlcNAcylation is an abundant post-translational modification in the nervous system, linked to both neurodevelopmental and neurodegenerative disease. However, the mechanistic links between these phenotypes and site-specific O-GlcNAcylation remain largely unexplored. Here, we show that Ser517 O-GlcNAcylation of the microtubule-binding protein Collapsin Response Mediator Protein-2 (CRMP2) increases with age. By generating and characterizing a Crmp2S517A knock-in mouse model, we demonstrate that loss of O-GlcNAcylation leads to a small decrease in body weight and mild memory impairment, suggesting that Ser517 O-GlcNAcylation has a small but detectable impact on mouse physiology and cognitive function. © 2019 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.
  • Lehmann, Laurent; Keller, Lukas F; Kokko, Hanna (2007)
    Female mate choice influences the maintenance of genetic variation by altering the mating success of males with different genotypes. The evolution of preferences themselves, on the other hand, depends on genetic variation present in the population. Few models have tracked this feedback between a choice gene and its effects on genetic variation, in particular when genes that determine offspring viability and attractiveness have dominance effects. Here we build a population genetic model that allows comparing the evolution of various choice rules in a single framework. We first consider preferences for good genes and show that focused preferences for homozygotes evolve more easily than broad preferences, which allow heterozygous males high mating success too. This occurs despite better maintenance of genetic diversity in the latter scenario, and we discuss why empirical findings of superior mating success of heterozygous males consequently do not immediately lead to a better understanding of the lek paradox. Our results thus suggest that the mechanisms that help maintain genetic diversity also have a flipside of making female choice an inaccurate means of producing the desired kind of offspring. We then consider preferences for heterozygosity per se, and show that these evolve only under very special conditions. Choice for compatible genotypes can evolve but its selective advantage diminishes quickly due to frequency-dependent selection. Finally, we show that our model reproduces earlier results on selfing, when the female choice strategy produces assortative mating. Overall, our model indicates that various forms of heterozygote-favouring (or variable) female choice pose a problem for the theory of sexual ornamentation based on indirect benefits, rather than a solution.
  • Societas pro Fauna et Flora Fennica. (Helsingfors [Societas pro Fauna et Flora Fennica], 1890)
    Meddelanden af Societas pro Fauna et Flora Fennica; 15-18
  • Societas pro Fauna et Flora Fennica. (Helsingfors [Societas pro Fauna et Flora Fennica], 1914)
    Meddelanden af Societas pro Fauna et Flora Fennica; 40-42
  • Societas pro Fauna et Flora Fennica. (Helsingfors [Societas pro Fauna et Flora Fennica], 1893)
    Meddelanden af Societas pro Fauna et Flora Fennica; 19-24
  • Societas pro Fauna et Flora Fennica. (Helsingfors [Societas pro Fauna et Flora Fennica], 1908)
    Meddelanden af Societas pro Fauna et Flora Fennica; 34-36
  • Societas pro Fauna et Flora Fennica. (Helsingfors [Societas pro Fauna et Flora Fennica], 1917)
    Meddelanden af Societas pro Fauna et Flora Fennica; 43-45
  • Societas pro Fauna et Flora Fennica. (Helsingfors [Societas pro Fauna et Flora Fennica], 1911)
    Meddelanden af Societas pro Fauna et Flora Fennica; 37-39
  • Societas pro Fauna et Flora Fennica. (Helsingfors [Societas pro Fauna et Flora Fennica], 1906)
    Meddelanden af Societas pro Fauna et Flora Fennica; 31-33
  • Societas pro Fauna et Flora Fennica. (Helsingfors [Societas pro Fauna et Flora Fennica], 1902)
    Meddelanden af Societas pro Fauna et Flora Fennica; 28-30
  • Societas pro Fauna et Flora Fennica. (Helsingfors [Societas pro Fauna et Flora Fennica], 1921)
    Meddelanden af Societas pro Fauna et Flora Fennica; 46-47
  • Hanski, Ilkka; Saccheri, Ilik (2006)
    The dynamics of natural populations are thought to be dominated by demographic and environmental processes with little influence of intraspecific genetic variation and natural selection, apart from inbreeding depression possibly reducing population growth in small populations. Here we analyse hundreds of well-characterised local populations in a large metapopulation of the Glanville fritillary butterfly (Melitaea cinxia), which persists in a balance between stochastic local extinctions and recolonisations in a network of 4,000 discrete habitat patches. We show that the allelic composition of the glycolytic enzyme phosphoglucose isomerase (Pgi) has a significant effect on the growth of local populations, consistent with previously reported effects of allelic variation on flight metabolic performance and fecundity in the Glanville fritillary and Colias butterflies. The strength and the sign of the molecular effect on population growth are sensitive to the ecological context (the area and spatial connectivity of the habitat patches), which affects genotype-specific gene flow and the influence of migration on the dynamics of local populations. The biological significance of the results for Pgi is underscored by lack of any association between population growth and allelic variation at six other loci typed in the same material. In demonstrating, to our knowledge for the first time, that molecular variation in a candidate gene affects population growth, this study challenges the perception that differential performance of individual genotypes, leading to differential fitness, is irrelevant to population dynamics. These results also demonstrate that the spatial configuration of habitat and spatial dynamics of populations contribute to maintenance of Pgi polymorphism in this species.
  • Hemilä, Harri O (1984)
  • Santos-Cortez, R.L.P.; Bhutta, M.F.; Earl, J.P.; Hafrén, Lena; Jennings, M.; Mell, J.C.; Pichichero, M.E.; Ryan, A.F.; Tateossian, Hilda; Ehrlich, G.D. (2020)
    Objective: To review the most recent advances in human and bacterial genomics as applied to pathogenesis and clinical management of otitis media. Data sources: PubMed articles published since the last meeting in June 2015 up to June 2019. Review methods: A panel of experts in human and bacterial genomics of otitis media was formed. Each panel member reviewed the literature in their respective fields and wrote draft reviews. The reviews were shared with all panel members, and a merged draft was created. The panel met at the 20th International Symposium on Recent Advances in Otitis Media in June 2019, discussed the review and refined the content. A final draft was made, circulated, and approved by the panel members. Conclusion: Trans-disciplinary approaches applying pan-omic technologies to identify human susceptibility to otitis media and to understand microbial population dynamics, patho-adaptation and virulence mechanisms are crucial to the development of novel, personalized therapeutics and prevention strategies for otitis media. Implications for practice: In the future otitis media prevention strategies may be augmented by mucosal immunization, combination vaccines targeting multiple pathogens, and modulation of the middle ear microbiome. Both treatment and vaccination may be tailored to an individual's otitis media phenotype as defined by molecular profiles obtained by using rapidly developing techniques in microbial and host genomics. © 2020 Elsevier B.V.