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  • 1
    Language: English
    In: Ecology (Durham), 2020-10, Vol.101 (10), p.e03105-n/a
    Description: Asexual species are thought to suffer more from coevolving parasites than related sexuals. Yet a variety of studies do not find the patterns predicted by theory. Here, to shine light on this conundrum, we investigate one such case of an asexual advantage in the presence of parasites. We follow the frequency dynamics of sexual and asexual Daphnia pulex in a natural pond that was initially dominated by sexuals. Coinciding with an epidemic of a microsporidian parasite infecting both sexuals and asexuals, the pond was rapidly taken over by the initially rare asexuals. With experiments comparing multiple sexual and asexual clones from across the local metapopulation, we confirm that asexuals are less susceptible and also suffer less from the parasite once infected. These results are consistent with the parasite‐driven, ecological replacement of dominant sexuals by closely related, but more resistant asexuals, ultimately leading to the extinction of the formerly superior sexual competitor. Our study is one of the clearest examples from nature, backed up by experimental verification, showing a parasite‐mediated reversal of competition dynamics. The experiments show that, across the metapopulation, asexuals have an advantage in the presence of parasites. In this metapopulation, asexuals are relatively rare, likely due to their recent invasion. While we cannot rule out other reasons for the observed patterns, the results are consistent with a temporary parasite‐mediated advantage of asexuals due to the fact that they are rare, which is an underappreciated aspect of the Red Queen Hypothesis.
    Subject(s): Animals ; asexual ; Daphnia ; ecological replacement ; Ecology, environment ; host–parasite interaction ; invasion biology ; Life Sciences ; microsporidia ; Parasites ; reproductive mode
    ISSN: 0012-9658
    E-ISSN: 1939-9170
    Source: Wiley Online Library All Journals
    Source: Alma/SFX Local Collection
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  • 2
    Language: English
    In: BMC evolutionary biology, 2017-12-15, Vol.17 (1), p.256-256
    Description: The Na,K-ATPase is a vital animal cell-membrane protein that maintains the cell's resting potential, among other functions. Cardenolides, a group of potent plant toxins, bind to and inhibit this pump. The gene encoding the α-subunit of the pump has undergone duplication events in some insect species known to feed on plants containing cardenolides. Here we test the function of these duplicated gene copies in the cardenolide-adapted milkweed bug, Oncopeltus fasciatus, which has three known copies of the gene: α1A, α1B and α1C. Using RT-qPCR analyses we demonstrate that the α1C is highly expressed in neural tissue, where the pump is generally thought to be most important for neuron excitability. With the use of in vivo RNAi in adult bugs we found that α1C knockdowns suffered high mortality, where as α1A and α1B did not, supporting that α1C is most important for effective ion pumping. Next we show a role for α1A and α1B in the handling of cardenolides: expression results find that both copies are primarily expressed in the Malpighian tubules, the primary insect organ responsible for excretion, and when we injected either α1A or α1B knockdowns with cardenolides this proved fatal (whereas not in controls). These results show that the Na,K-ATPα gene-copies have taken on diverse functions. Having multiple copies of this gene appears to have allowed the newly arisen duplicates to specialize on resistance to cardenolides, whereas the ancestral copy of the pump remains comparatively sensitive, but acts as a more efficient ion carrier. Interestingly both the α1A and α1B were required for cardenolide handling, suggesting that these two copies have separate and vital functions. Gene duplications of the Na,K-ATPase thus represent an excellent example of subfunctionalization in response to a new environmental challenge.
    Subject(s): Adenosine triphosphatase ; Amino Acid Sequence ; Analysis ; Animals ; Cardenolides ; Cardenolides - chemistry ; Cardenolides - metabolism ; Cells ; Coevolution ; Evolution, Molecular ; Feed industry ; Gene Dosage ; Gene Duplication ; Gene expression ; Gene Expression Profiling ; Gene Knockdown Techniques ; Genes ; Heteroptera - enzymology ; Heteroptera - genetics ; Milkweed bug ; Oncopeltus fasciatus ; Organ Specificity ; Phenotype ; RNAi ; Sodium-Potassium-Exchanging ATPase - chemistry ; Sodium-Potassium-Exchanging ATPase - genetics
    ISSN: 1471-2148
    E-ISSN: 1471-2148
    Source: BioMedCentral Open Access
    Source: Academic Search Ultimate
    Source: PubMed Central
    Source: DOAJ Directory of Open Access Journals - Not for CDI Discovery
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  • 3
    Article
    Article
    2017
    ISSN: 0014-3820 
    Language: English
    In: Evolution, 2017-03-01, Vol.71 (3), p.808-809
    Description: Zwoinska et al. address an important question in the science of aging, namely whether diverse aging pathologies share a common genetic architecture.The independence of aging pathologies shown by Zwoinska et al. in Drosophila supports the more complex scenario predicted by evolutionary theory, where multiple pathways are involved. Addressing the diverse mechanisms and their evolutionary background will help to understand aging pathologies and may prove key in teasing apart the differences between healthspan and lifespan.
    Subject(s): Aging ; Analysis ; DIGESTS ; Drosophila ; Evolutionary biology ; Genetic aspects ; Humans ; Physiological aspects
    ISSN: 0014-3820
    E-ISSN: 1558-5646
    Source: JSTOR Life Sciences
    Source: Alma/SFX Local Collection
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  • 4
    Language: English
    In: Evolution, 2015-12, Vol.69 (12), p.3109-3122
    Description: Reduced population size is thought to have strong consequences for evolutionary processes as it enhances the strength of genetic drift. In its interaction with selection, this is predicted to increase the genetic load, reduce inbreeding depression, and increase hybrid vigor, and in turn affect phenotypic evolution. Several of these predictions have been tested, but comprehensive studies controlling for confounding factors are scarce. Here, we show that populations of Daphnia magna, which vary strongly in genetic diversity, also differ in genetic load, inbreeding depression, and hybrid vigor in a way that strongly supports theoretical predictions. Inbreeding depression is positively correlated with genetic diversity (a proxy for Ne), and genetic load and hybrid vigor are negatively correlated with genetic diversity. These patterns remain significant after accounting for potential confounding factors and indicate that, in small populations, a large proportion of the segregation load is converted into fixed load. Overall, the results suggest that the nature of genetic variation for fitness-related traits differs strongly between large and small populations. This has large consequences for evolutionary processes in natural populations, such as selection on dispersal, breeding systems, ageing, and local adaptation.
    Subject(s): Alleles ; Analysis ; Animals ; Biological diversity ; Daphnia ; Daphnia - genetics ; Daphnia - physiology ; Dispersal (Ecology) ; drift load ; Evolution ; Genetic diversity ; genetic drift ; Genetic Load ; heterosis ; Hybrid Vigor ; Inbreeding ; Inbreeding depression ; Models, Genetic ; Phenotypic traits ; Population Density ; Population genetics ; Population size ; Research ; seragation load
    ISSN: 0014-3820
    E-ISSN: 1558-5646
    Source: JSTOR Life Sciences
    Source: Alma/SFX Local Collection
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  • 5
    Language: English
    In: Development (Cambridge), 2005-10-15, Vol.132 (20), p.4611-4619
    Description: The diversification of neural-crest-derived sympathoadrenal (SA) progenitor cells into sympathetic neurons and neuroendocrine adrenal chromaffin cells was thought to be largely understood. In-vitro studies with isolated SA progenitor cells had suggested that chromaffin cell differentiation depends crucially on glucocorticoids provided by adrenal cortical cells. However, analysis of mice lacking the glucocorticoid receptor gene had revealed that adrenal chromaffin cells develop mostly normally in these mice. Alternative cues from the adrenal cortex that may promote chromaffin cell determination and differentiation have not been identified. We therefore investigated whether the chromaffin cell phenotype can develop in the absence of an adrenal cortex, using mice deficient for the nuclear orphan receptor steroidogenic factor-1 (SF1), which lack adrenal cortical cells and gonads. We show that in Sf1 –/– mice typical chromaffin cells assemble correctly in the suprarenal region adjacent to the suprarenal sympathetic ganglion. The cells display most features of chromaffin cells, including the typical large chromaffin granules. Sf1 –/– chromaffin cells are numerically reduced by about 50% compared with the wild type at embryonic day (E) 13.5 and E17.5. This phenotype is not accounted for by reduced survival or cell proliferation beyond E12.5. However, already at E12.5 the `adrenal' region in Sf1 –/– mice is occupied by fewer PHOX2B + and TH + SA cells as well as SOX10 + neural crest cells. Our results suggest that cortical cues are not essential for determining chromaffin cell fate, but may be required for proper migration of SA progenitors to and/or colonization of the adrenal anlage.
    Subject(s): Adrenal Cortex - cytology ; Adrenal Cortex - embryology ; Adrenal Cortex - metabolism ; Animals ; Cell Differentiation ; Chromaffin Cells - cytology ; Chromaffin Cells - metabolism ; Gene Expression Regulation, Developmental ; High Mobility Group Proteins - metabolism ; Homeodomain Proteins - genetics ; Homeodomain Proteins - metabolism ; Mice ; Mice, Knockout ; Microscopy, Electron ; Mutation - genetics ; Neoplasm Proteins - metabolism ; Receptors, Cytoplasmic and Nuclear - deficiency ; Receptors, Cytoplasmic and Nuclear - genetics ; Receptors, Cytoplasmic and Nuclear - metabolism ; SOXE Transcription Factors ; Steroidogenic Factor 1 ; Transcription Factors - deficiency ; Transcription Factors - genetics ; Transcription Factors - metabolism
    ISSN: 0950-1991
    E-ISSN: 1477-9129
    Source: HighWire Press (Free Journals)
    Source: Elektronische Zeitschriftenbibliothek - Frei zugängliche E-Journals
    Source: Company of Biologists
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  • 6
    Language: English
    In: Cancer science, 2009-07, Vol.100 (7), p.1210-1218
    Description: Head and neck squamous cell carcinoma has still a poor prognosis. Since angiogenesis is crucial for tumor growth, a better understanding of the potential clinical relevance as well as the interactions between the numerous proangiogenic growth factors is essential to develop improved therapeutic strategies in these tumors. Expression levels of eight growth factors known to induce angiogenesis (HGF, bFGF, VEGF-A, VEGF-D, PDGF-AB, PDGF-BB, G-CSF, and GM-CSF) were quantitatively measured by ELISA in homogenates of 41 head and neck squamous cell carcinomas. In addition, microvessel density and protein localization of growth factors were assessed by immunohistochemistry. Statistical analysis was performed to assess interrelationships between growth factors analyzed and to correlate protein levels with patient outcome. In 90% of the tissues at least 4/8 growth factors analyzed were detectable. Highest amounts and most frequent expression were found for HGF, bFGF and VEGF-A while PDGF-AB and PDGF-BB were present in two-thirds and G-CSF and GM-CSF in approximately half of the cases. Although there was no significant relation to microvessel density, we identified significant associations for bFGF with HGF and G-CSF as well as of PDGF-AB with those of VEGF-A and PDGF-BB. For the first time we demonstrate that expression levels of HGF as well as that of bFGF and G-CSF in head and neck squamous tumors are negative prognostic factors for patient survival. Our data indicate a network of interrelated and prognostically relevant growth factors in these tumors that have to be taken into consideration when planning an antiangiogenic and antitumor therapy. (Cancer Sci 2009; 100: 1210-1218)
    Subject(s): Analysis ; Angiogenesis Inducing Agents - metabolism ; Biological and medical sciences ; Carcinoma, Squamous Cell - blood supply ; Carcinoma, Squamous Cell - metabolism ; Carcinoma, Squamous Cell - mortality ; Colony-stimulating factors (Physiology) ; Enzyme-linked immunosorbent assay ; Granulocyte-Macrophage Colony-Stimulating Factor - metabolism ; Growth factors ; Head and Neck Neoplasms - blood supply ; Head and Neck Neoplasms - metabolism ; Head and Neck Neoplasms - mortality ; Health aspects ; Humans ; Immunohistochemistry ; Intercellular Signaling Peptides and Proteins - metabolism ; Medical sciences ; Neovascularization, Pathologic - metabolism ; Otorhinolaryngology (head neck, general aspects and miscellaneous) ; Otorhinolaryngology. Stomatology ; Platelet-Derived Growth Factor - metabolism ; Prognosis ; Proto-Oncogene Proteins c-sis ; Squamous cell carcinoma ; Tumors ; Vascular Endothelial Growth Factor A - metabolism ; Vascular Endothelial Growth Factor D - metabolism
    ISSN: 1347-9032
    E-ISSN: 1349-7006
    Source: Alma/SFX Local Collection
    Source: ProQuest Central
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  • 7
    Language: English
    In: Evolution, 2011-05, Vol.65 (5), p.1482-1488
    Description: Inducible defensive traits against herbivores or predators are widespread in plants and animals. Theory predicts that defended morphs have greater fitness in the presence of predators, but lower fitness than undefended morphs in the absence of predators. If such costs did not exist, then a constitutively defended morph would be favored by natural selection; yet, evidence for such costs has been elusive. Our current work reveals a significant cost to inducible defenses. Using the waterflea (Daphnia) model system, we show that induced defended morphs are significantly more vulnerable to infection by a virulent yeast parasite than undefended morphs. In two independent experiments, the proportion of successful infections and the number of parasite spores were higher among defended versus undefended Daphnia. Thus, by demonstrating a previously unknown and environmentally relevant cost to inducible defenses, this study enhances our understanding of adaptive phenotypic plasticity and its evolution.
    Subject(s): Adaptation (Biology) ; Adaptation, Physiological ; Animals ; Biological Evolution ; BRIEF COMMUNICATION ; Cladocera ; Daphnia - microbiology ; Daphnia - physiology ; Ecological genetics ; Ecological life histories ; Evolution ; Female ; Fish ; Food Chain ; Genetic aspects ; Germany ; Inducible defenses ; Infections ; Kairomones ; Metschnikowia ; Metschnikowia - physiology ; Parasite hosts ; Parasites ; Phenotypic plasticity ; Pheromones - metabolism ; Physiological aspects ; Predators ; Research ; Selection, Genetic ; Spores
    ISSN: 0014-3820
    E-ISSN: 1558-5646
    Source: JSTOR Life Sciences
    Source: Alma/SFX Local Collection
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  • 8
    Language: English
    In: Cell and tissue research, 2006-09, Vol.325 (3), p.437-444
    Description: Adrenal medullary chromaffin cells are derivatives of the neural crest and are widely believed to share a common sympathoadrenal (SA) progenitor with sympathetic neurons. For decades, the adrenal cortical environment was assumed to be essential for channelling SA progenitors towards an endocrine chromaffin cell fate. Our recent analysis of steroidogenic factor 1(Sf1) −/− mice, which lack an adrenal cortex, has challenged this view: in Sf1 −/− mice chromaffin cells migrate to the correct “adrenal” location and undergo largely normal differentiation. In contrast to Sf1 homozygous mutants, heterozygous animals have an adrenal cortex, which, however, is smaller than in wildtype littermates. We show here that the Sf1 +/− adrenal cortical anlagen attract normal numbers of chromaffin progenitor cells into their vicinity by embryonic day 13.5 (E13.5). Two days later, however, only a few scattered cells with highly immature features have immigrated into the adrenal cortex, whereas the remainder form a coherent cell assembly ectopically located at the medial surface of the gland. These cells appear more mature than the scattered intracortical chromaffin progenitors and express the adrenaline synthesizing enzyme PNMT with a delay of 1 day in comparison with wildtype littermates. Nevertheless, chromaffin progenitor cells undergo a numerical reduction of approximately 30% by E17.5. Together, our data suggest that normal adrenocortical development is critical for the correct immigration of chromaffin progenitors into the cortical anlagen, for the timing of PNMT expression and for the regulation of chromaffin cell numbers.
    Subject(s): Adrenal chromaffin cells ; Adrenal Glands - cytology ; Adrenal Glands - embryology ; Adrenal Glands - growth & development ; Adrenal Glands - metabolism ; Adrenal Glands - ultrastructure ; Animals ; Biomedicine ; Chromaffin Cells - cytology ; Chromaffin Cells - metabolism ; Chromaffin Cells - ultrastructure ; Crosses, Genetic ; Heterozygote ; Human Genetics ; Immunohistochemistry ; In Situ Hybridization ; Mice ; Mice, Inbred C57BL ; Mice, Mutant Strains ; Molecular Medicine ; Mouse ( Sf1 +/−) ; PNMT ; Proteomics ; Sf1 ; Sympathoadrenal cell lineage ; Tyrosine hydroxylase
    ISSN: 0302-766X
    E-ISSN: 1432-0878
    Source: Alma/SFX Local Collection
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  • 9
    Language: English
    In: Evolution, 2014-09, Vol.68 (9), p.2494-2508
    Description: Explaining the strong variation in lifespan among organisms remains a major challenge in evolutionary biology. Whereas previous work has concentrated mainly on differences in selection regimes and selection pressures, we hypothesize that differences in genetic drift may explain some of this variation. We develop a model to formalize this idea and show that the strong positive relationship between lifespan and genetic diversity predicted by this model indeed exists among populations of Daphnia magna, and that ageing is accelerated in small populations. Additional results suggest that this is due to increased drift in small populations rather than adaptation to environments favoring faster life histories. First, the correlation between genetic diversity and lifespan remains significant after statistical correction for potential environmental covariates. Second, no trade-offs are observed; rather, all investigated traits show clear signs of increased genetic load in the small populations. Third, hybrid vigor with respect to lifespan is observed in crosses between small but not between large populations. Together, these results suggest that the evolution of lifespan and ageing can be strongly affected by genetic drift, especially in small populations, and that variation in lifespan and ageing may often be nonadaptive, due to a strong contribution from mutation accumulation.
    Subject(s): Aging ; Aging - genetics ; Alleles ; Analysis ; Animals ; Biological diversity ; Daphnia ; Daphnia - genetics ; Ecological life histories ; Evolution ; Evolutionary genetics ; Genetic diversity ; Genetic Drift ; Genetic mutation ; Genetic Variation ; Hybrid Vigor ; Life cycles (Biology) ; Longevity - genetics ; Modeling ; Models, Genetic ; Mortality ; Mutation ; mutation accumulation ; Phenotype ; Population genetics ; Population size ; Research ; senescence
    ISSN: 0014-3820
    E-ISSN: 1558-5646
    Source: JSTOR Life Sciences
    Source: Alma/SFX Local Collection
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  • 10
    Language: English
    In: Brain (London, England : 1878), 2012, Vol.135 (Pt 4), p.1042-1054
    Description: Peptides presented at the cell surface reflect the protein content of the cell; those on HLA class I molecules comprise the critical peptidome elements interacting with CD8 T lymphocytes. We hypothesize that peptidomes from ex vivo tumour samples encompass immunogenic tumour antigens. Here, we uncover 〉6000 HLA-bound peptides from HLA-A*02(+) glioblastoma, of which over 3000 were restricted by HLA-A*02. We prioritized in-depth investigation of 10 glioblastoma-associated antigens based on high expression in tumours, very low or absent expression in healthy tissues, implication in gliomagenesis and immunogenicity. Patients with glioblastoma showed no T cell tolerance to these peptides. Moreover, we demonstrated specific lysis of tumour cells by patients' CD8(+) T cells in vitro. In vivo, glioblastoma-specific CD8(+) T cells were present at the tumour site. Overall, our data show the physiological relevance of the peptidome approach and provide a critical advance for designing a rational glioblastoma immunotherapy. The peptides identified in our study are currently being tested as a multipeptide vaccine (IMA950) in patients with glioblastoma.
    Subject(s): Abridged Index Medicus ; Antigen Presentation - physiology ; Antigens, CD - metabolism ; Antigens, Neoplasm - chemistry ; Antigens, Neoplasm - immunology ; Antigens, Neoplasm - therapeutic use ; Biological and medical sciences ; Brain Neoplasms - immunology ; Brain Neoplasms - pathology ; Brain Neoplasms - therapy ; CD8-Positive T-Lymphocytes - immunology ; Chromatography, Liquid ; Cytokines - metabolism ; Flow Cytometry ; Gene Expression Profiling ; Glial Fibrillary Acidic Protein - metabolism ; Glioblastoma - immunology ; Glioblastoma - pathology ; Glioblastoma - therapy ; HLA-A Antigens - analysis ; HLA-A Antigens - chemistry ; HLA-A Antigens - immunology ; Humans ; Mass Spectrometry ; Medical sciences ; Neurology ; Oligonucleotide Array Sequence Analysis ; Peptides - analysis ; Peptides - immunology ; Platelet Endothelial Cell Adhesion Molecule-1 - metabolism ; Receptor-Like Protein Tyrosine Phosphatases, Class 5 - metabolism ; RNA, Messenger - metabolism ; Sequence Analysis, Protein ; Tumors of the nervous system. Phacomatoses
    ISSN: 0006-8950
    E-ISSN: 1460-2156
    Source: Elektronische Zeitschriftenbibliothek - Frei zugängliche E-Journals
    Source: Alma/SFX Local Collection
    Source: Oxford Journals 2016 Current and Archive A-Z Collection
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