RESUMO
Conservation biology was founded on the idea that efforts to save nature depend on a scientific understanding of how it works. It sought to apply ecological principles to conservation problems. We investigated whether the relationship between these fields has changed over time through machine reading the full texts of 32,000 research articles published in 16 ecology and conservation biology journals. We examined changes in research topics in both fields and how the fields have evolved from 2000 to 2014. As conservation biology matured, its focus shifted from ecology to social and political aspects of conservation. The 2 fields diverged and now occupy distinct niches in modern science. We hypothesize this pattern resulted from increasing recognition that social, economic, and political factors are critical for successful conservation and possibly from rising skepticism about the relevance of contemporary ecological theory to practical conservation.
Relaciones entre la Biología de la Conservación y la Ecología Mostradas a través de la Lectura Mediante Máquina de 32,000 Artículos Resumen La biología de la conservación se fundó a partir de la idea de que los esfuerzos para salvar a la naturaleza dependen del entendimiento científico de cómo funciona. La biología de la conservación buscaba aplicar los principios ecológicos a los problemas de conservación. En este trabajo investigamos si la relación entre estos ámbitos ha cambiado con el tiempo al realizar una lectura mediante máquina de 32,000 textos completos de artículos de investigación publicados en 16 revistas sobre ecología y biología de la conservación. También examinamos los cambios en los temas de investigación en ambos ámbitos y cómo éstos han evolucionado desde el año 2000 hasta el 2014. Conforme ha madurado la biología de la conservación, su enfoque se ha movido de los aspectos ecológicos de la conservación a los aspectos políticos y sociales. La ecología y la biología de la conservación se han separado y ahora ocupan nichos distintos dentro de la ciencia moderna. Nuestra hipótesis considera que este patrón resultó de incrementar el reconocimiento de que los factores sociales, económicos y políticos son muy importantes para una conservación exitosa. Posiblemente el patrón también proviene del creciente escepticismo acerca de la relevancia que la teoría ecológica contemporánea tiene para la conservación en práctica.
Assuntos
Conservação dos Recursos Naturais , EcologiaRESUMO
Human longevity continues to increase world-wide, often accompanied by decreasing birth rates. As a larger fraction of the population thus gets older, the number of people suffering from disease or disability increases dramatically, presenting a major societal challenge. Healthy ageing has therefore been selected by EU policy makers as an important priority ( http://www.healthyageing.eu/european-policies-and-initiatives ); it benefits not only the elderly but also their direct environment and broader society, as well as the economy. The theme of healthy ageing figures prominently in the Horizon 2020 programme ( https://ec.europa.eu/programmes/horizon2020/en/h2020-section/health-demographic-change-and-wellbeing ), which has launched several research and innovation actions (RIA), like "Understanding health, ageing and disease: determinants, risk factors and pathways" in the work programme on "Personalising healthcare" ( https://ec.europa.eu/research/participants/portal/desktop/en/opportunities/h2020/topics/693-phc-01-2014.html ). Here we present our research proposal entitled "ageing with elegans" (AwE) ( http://www.h2020awe.eu/ ), funded by this RIA, which aims for better understanding of the factors causing health and disease in ageing, and to develop evidence-based prevention, diagnostic, therapeutic and other strategies. The aim of this article, authored by the principal investigators of the 17 collaborating teams, is to describe briefly the rationale, aims, strategies and work packages of AwE for the purposes of sharing our ideas and plans with the biogerontological community in order to invite scientific feedback, suggestions, and criticism.
Assuntos
Envelhecimento/fisiologia , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/fisiologia , Estilo de Vida Saudável/fisiologia , Longevidade/fisiologia , Modelos Animais , AnimaisRESUMO
Many mutations and allelic variants are known that influence the rate at which animals age, but when in life do such variants diverge from normal patterns of aging? Is this divergence visible in their physiologies? To investigate these questions, we have used (1)H NMR spectroscopy to study how the metabolome of the nematode Caenorhabditis elegans changes as it grows older. We identify a series of metabolic changes that, collectively, predict the age of wild-type worms. We then show that long-lived mutant daf-2(m41) worms are metabolically youthful compared to wild-type worms, but that this relative youth only appears in middle age. Finally, we show that metabolic age predicts the timing and magnitude of differences in age-specific mortality between these strains. Thus, the future mortality of these two genotypes can be predicted long before most of the worms die.
Assuntos
Envelhecimento/metabolismo , Aminoácidos/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Metaboloma , Receptor de Insulina/metabolismo , Trealose/metabolismo , Envelhecimento/genética , Aminoácidos/farmacologia , Animais , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Regulação da Expressão Gênica , Genótipo , Modelos Lineares , Longevidade/genética , Espectroscopia de Ressonância Magnética , Mutação , Receptor de Insulina/genética , Trealose/farmacologiaRESUMO
Music evolves as composers, performers, and consumers favor some musical variants over others. To investigate the role of consumer selection, we constructed a Darwinian music engine consisting of a population of short audio loops that sexually reproduce and mutate. This population evolved for 2,513 generations under the selective influence of 6,931 consumers who rated the loops' aesthetic qualities. We found that the loops quickly evolved into music attributable, in part, to the evolution of aesthetically pleasing chords and rhythms. Later, however, evolution slowed. Applying the Price equation, a general description of evolutionary processes, we found that this stasis was mostly attributable to a decrease in the fidelity of transmission. Our experiment shows how cultural dynamics can be explained in terms of competing evolutionary forces.
Assuntos
Comportamento do Consumidor/estatística & dados numéricos , Evolução Cultural , Modelos Teóricos , Música , Estimulação Acústica , Algoritmos , Simulação por Computador , Estética , HumanosRESUMO
Cancers are often thought to be selectively neutral. This is because most of the individuals that they kill are post-reproductive. Some cancers, however, kill the young and so select for anticancer adaptations that reduce the chance of death. These adaptations could reduce the somatic mutation rate or the selective value of a mutant clone of cells, or increase the number of stages required for neoplasia. New theory predicts that cancer selection--selection to prevent or postpone deaths due to cancer--should be especially important as animals evolve new morphologies or larger, longer-lived bodies, and might account for some of the differences in the causes of cancer between mice and men.
Assuntos
Modelos Biológicos , Neoplasias/genética , Seleção Genética , Adolescente , Adulto , Idade de Início , Animais , Constituição Corporal , Cruzamento , Transformação Celular Neoplásica/genética , Galinhas , Criança , Ciprinodontiformes , Doenças do Cão/genética , Doenças do Cão/patologia , Doenças do Cão/transmissão , Cães , Feminino , Doenças dos Peixes/genética , Doenças dos Peixes/patologia , Genes Supressores de Tumor , Predisposição Genética para Doença , Substâncias de Crescimento/fisiologia , Humanos , Masculino , Melanoma/genética , Melanoma/patologia , Melanoma/veterinária , Camundongos , Camundongos Knockout , Mutação , Neoplasias/epidemiologia , Neoplasias/prevenção & controle , Neoplasias/veterinária , Especificidade de Órgãos , Doenças das Aves Domésticas/genética , Sarcoma/genética , Sarcoma/patologia , Sarcoma/veterinária , Infecções Sexualmente Transmissíveis/genética , Infecções Sexualmente Transmissíveis/patologia , Infecções Sexualmente Transmissíveis/veterinária , Especificidade da Espécie , Neoplasias Urogenitais/genética , Neoplasias Urogenitais/patologia , Neoplasias Urogenitais/veterinária , BaleiasRESUMO
The nematode Caenorhabditis elegans is widely used as a model organism in many areas of the life sciences. Metabolite profiling (metabolomics/metabonomics) is a powerful means of assigning phenotypes to experimentally perturbed C. elegans samples (e.g., mutants, RNAi, or chemical treatments). Tissue extraction is a key step, and high-quality and reproducible extractions are essential to the success of metabolomics studies. We have performed an extensive comparison of different tissue extraction techniques with C. elegans, comparing two different solvent systems (chloroform/methanol and aqueous methanol) and six different tissue disruption techniques (including manual grinding in a cooled mortar, homogenization, and various grinding media in both reciprocating and orbital tissue mills). All twelve combinations were then compared by GC/MS, (1)H NMR spectroscopy, and UPLC-MS, and the results were evaluated by both overall multivariate clustering approaches as well as distributions over individual metabolites/metabolite features of coefficient of variation and yield. The choice of solvent had more influence than the disruption method used, although the homogenizer results were clearly outliers. Overall, we concluded that bead-beating with 80% methanol solution was a good trade-off, although it is important to note that the definition of the apparent "best" method depended on which analytical platform was used to evaluate the results.
Assuntos
Caenorhabditis elegans/metabolismo , Metaboloma , Metabolômica/métodos , Animais , Clorofórmio/química , Cromatografia Líquida de Alta Pressão/métodos , Análise por Conglomerados , Cromatografia Gasosa-Espectrometria de Massas/métodos , Espectroscopia de Ressonância Magnética/métodos , Metanol/química , Fenótipo , Interferência de RNA , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Água/químicaRESUMO
Developmental processes are thought to be highly complex, but there have been few attempts to measure and compare such complexity across different groups of organisms. Here we introduce a measure of biological complexity based on the similarity between developmental and computer programs. We define the algorithmic complexity of a cell lineage as the length of the shortest description of the lineage based on its constituent sublineages. We then use this measure to estimate the complexity of the embryonic lineages of four metazoan species from two different phyla. We find that these cell lineages are significantly simpler than would be expected by chance. Furthermore, evolutionary simulations show that the complexity of the embryonic lineages surveyed is near that of the simplest lineages evolvable, assuming strong developmental constraints on the spatial positions of cells and stabilizing selection on cell number. We propose that selection for decreased complexity has played a major role in moulding metazoan cell lineages.
Assuntos
Evolução Biológica , Linhagem da Célula , Rhabditoidea/citologia , Rhabditoidea/embriologia , Urocordados/citologia , Urocordados/embriologia , Algoritmos , Animais , Caenorhabditis elegans/citologia , Caenorhabditis elegans/embriologia , Simulação por Computador , Modelos BiológicosRESUMO
BACKGROUND: Many Caenorhabditis elegans mutations increase longevity and much evidence suggests that they do so at least partly via changes in metabolism. However, up until now there has been no systematic investigation of how the metabolic networks of long-lived mutants differ from those of normal worms. Metabolomic technologies, that permit the analysis of many untargeted metabolites in parallel, now make this possible. Here we use one of these, 1H nuclear magnetic resonance spectroscopy, to investigate what makes long-lived worms metabolically distinctive. RESULTS: We examined three classes of long-lived worms: dauer larvae, adult Insulin/IGF-1 signalling (IIS)-defective mutants, and a translation-defective mutant. Surprisingly, these ostensibly different long-lived worms share a common metabolic signature, dominated by shifts in carbohydrate and amino acid metabolism. In addition the dauer larvae, uniquely, had elevated levels of modified amino acids (hydroxyproline and phosphoserine). We interrogated existing gene expression data in order to integrate functional (metabolite-level) changes with transcriptional changes at a pathway level. CONCLUSIONS: The observed metabolic responses could be explained to a large degree by upregulation of gluconeogenesis and the glyoxylate shunt as well as changes in amino acid catabolism. These responses point to new possible mechanisms of longevity assurance in worms. The metabolic changes observed in dauer larvae can be explained by the existence of high levels of autophagy leading to recycling of cellular components.See associated minireview: http://jbiol.com/content/9/1/7.
Assuntos
Caenorhabditis elegans/crescimento & desenvolvimento , Caenorhabditis elegans/metabolismo , Longevidade/fisiologia , Aminoácidos/metabolismo , Animais , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/fisiologia , Metabolismo dos Carboidratos/genética , Metabolismo dos Carboidratos/fisiologia , Gluconeogênese/genética , Gluconeogênese/fisiologia , Glioxilatos/metabolismo , Insulina/genética , Insulina/metabolismo , Fator de Crescimento Insulin-Like I/genética , Fator de Crescimento Insulin-Like I/metabolismo , Larva/genética , Larva/crescimento & desenvolvimento , Larva/metabolismo , Longevidade/genética , Espectroscopia de Ressonância Magnética , Modelos Biológicos , Mutação , Receptor de Insulina/genética , Receptor de Insulina/fisiologiaRESUMO
Canine transmissible venereal tumor (CTVT) is an intriguing cancer that is transmitted naturally as an allograft by transplantation of viable tumor cells from affected to susceptible dogs. At least initially, the tumor is able to evade the host's immune response; thus, CTVT has potential to provide novel insights into tumor immunobiology. The nature of CTVT as a "contagious" cancer, originating from a common ancestral source of infection, has been demonstrated previously by a series of studies comparing geographically distinct tumors at the molecular level. While these studies have revealed that apparently unrelated tumors share a striking degree of karyotypic conservation, technological restraints have limited the ability to investigate the chromosome composition of CTVTs in any detail. We present characterization of a strategically selected panel of CTVT cases using microarray-based comparative genomic hybridization analysis at ~one-megabase resolution. These data show for the first time that the tumor presents with an extensive range of non-random chromosome copy number aberrations that are distributed widely throughout the dog genome. The majority of abnormalities detected were imbalances of small subchromosomal regions, often involving centromeric and telomeric sequences. All cases also showed the sex chromosome complement XO. There was remarkable conservation in the cytogenetic profiles of the tumors analyzed, with only minor variation observed between different cases. These data suggest that the CTVT genome demonstrates a vast degree of both structural and numerical reorganization that is maintained during transmission among the domestic dog population.
Assuntos
Variações do Número de Cópias de DNA , Doenças do Cão/genética , Genoma , Tumores Venéreos Veterinários/genética , Animais , Hibridização Genômica Comparativa , Doenças do Cão/imunologia , Doenças do Cão/transmissão , Cães , Feminino , Regulação Neoplásica da Expressão Gênica , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , Tumores Venéreos Veterinários/imunologiaRESUMO
Neutral models of evolution assume the absence of natural selection. Formerly confined to ecology and evolutionary biology, neutral models are spreading. In recent years they've been applied to explaining the diversity of baby names, scientific citations, cryptocurrencies, pot decorations, literary lexica, tumour variants and much more besides. Here, we survey important neutral models and highlight their similarities. We investigate the most widely used tests of neutrality, show that they are weak and suggest more powerful methods. We conclude by discussing the role of neutral models in the explanation of diversity. We suggest that the ability of neutral models to fit low-information distributions should not be taken as evidence for the absence of selection. Nevertheless, many studies, in increasingly diverse fields, make just such claims. We call this tendency 'neutral syndrome'.
Assuntos
Evolução Biológica , Modelos Biológicos , Seleção Genética , Animais , Biodiversidade , Deriva Genética , MutaçãoRESUMO
OBJECTIVE: To determine how the representation of women's health has changed in clinical studies over the course of 70 years. DESIGN: Observational study of 71 866 research articles published between 1948 and 2018 in The BMJ. MAIN OUTCOME MEASURES: The incidence of women-specific health topics over time. General linear, additive and segmented regression models were used to estimate trends. RESULTS: Over 70 years, the overall odds that a word in a BMJ research article was 'woman' or 'women' increased by an annual factor of 1.023, but this rate of increase varied by clinical specialty with some showing little or no change. The odds that an article was about some aspect of women-specific health increased much more slowly, by an annual factor of 1.004. The incidence of articles about particular areas of women-specific medicine such as pregnancy did not show a general increase, but rather fluctuated over time. The incidence of articles making any mention of women, gender or sex declined between 1948 and 2005, after which it rose steeply so that by 2018 few papers made no mention of them at all. CONCLUSIONS: Over time women have become ever more prominent in BMJ research articles. However, the importance of women-specific health topics has waxed and waned as researchers responded ephemerally to medical advances, public health programmes, and sociolegal changes. The appointment of a woman editor-inchief in 2005 may have had a dramatic effect on whether women were mentioned in research articles.
Assuntos
Ciência de Dados , Saúde da Mulher , Feminino , Humanos , Gravidez , Saúde Pública , Editoração , PesquisadoresRESUMO
Here we investigate the evolutionary dynamics of several kinds of modern cultural artefacts-pop music, novels, the clinical literature and cars-as well as a collection of organic populations. In contrast to the general belief that modern culture evolves very quickly, we show that rates of modern cultural evolution are comparable to those of many animal populations. Using time-series methods, we show that much of modern culture is shaped by either stabilizing or directional forces or both and that these forces partly regulate the rates at which different traits evolve. We suggest that these forces are probably cultural selection and that the evolution of many artefact traits can be explained by a shifting-optimum model of cultural selection that, in turn, rests on known psychological biases in aesthetic appreciation. In sum, our results demonstrate the deep unity of the processes and patterns of cultural and organic evolution.
Assuntos
Evolução Cultural , Cultura , Animais , Evolução Biológica , Humanos , Modelos Teóricos , Fatores de TempoRESUMO
Some animals, such as the larvae of Drosophila melanogaster, the larvae of the Appendicularian chordate Oikopleura, and the adults of the nematode Caenorhabditis elegans, are unusual in that they grow largely by increases in cell size. The giant cells of such species are highly polyploid, having undergone repeated rounds of endoreduplication. Since germline polyploid strains tend to have large cells, it is often assumed that endoreduplication drives cell growth, but this remains controversial. We have previously shown that adult growth in C. elegans is associated with the endoreduplication of nuclei in the epidermal syncitium, hyp 7. We show here that this relationship is causal. Manipulation of somatic ploidy both upwards and downwards increases and decreases, respectively, adult body size. We also establish a quantitative relationship between ploidy and body size. Finally, we find that TGF-beta (DBL-1) and cyclin E (CYE-1) regulate body size via endoreduplication. To our knowledge, this is the first experimental evidence establishing a cause-and-effect relationship between somatic polyploidization and body size in a metazoan.
Assuntos
Caenorhabditis elegans/crescimento & desenvolvimento , Caenorhabditis elegans/genética , Ploidias , Animais , Caenorhabditis elegans/efeitos dos fármacos , Proteínas de Caenorhabditis elegans/fisiologia , Crescimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Ciclina E/fisiologia , DNA/biossíntese , Comportamento Alimentar , Hidroxiureia/farmacologia , Neuropeptídeos/fisiologia , Inibidores da Síntese de Ácido Nucleico/farmacologia , Fator de Crescimento Transformador beta/fisiologiaRESUMO
The nematode Caenorhabditis elegans grows largely by increases in cell size. As a consequence of this, the surface: volume ratio of its cells must decline in the course of postembryonic growth. Here we use transcriptomic and metabolomic data to show that this change in geometry can explain a variety of phenomena during growth, including: (i) changes in the relative expression levels of cytoplasmic and membrane proteins; (ii) changes in the relative usage of the twenty amino acids in expressed proteins, as estimated by changes in the transcriptome; and (iii) changes in metabolite pools of free amino acids. We expect these relations to be universal in single cells and in whole multicellular organisms that grow largely by increases in cell size, but not those that grow by cell proliferation.
Assuntos
Aminoácidos/metabolismo , Caenorhabditis elegans/crescimento & desenvolvimento , Caenorhabditis elegans/metabolismo , Crescimento Celular , Envelhecimento , Animais , Caenorhabditis elegans/citologia , Proliferação de CélulasRESUMO
Nuclear magnetic resonance (NMR) spectroscopy is widely used as a metabolomics tool, and 1D spectroscopy is overwhelmingly the commonest approach. The use of 2D spectroscopy could offer significant advantages in terms of increased spectral dispersion of peaks, but has a number of disadvantages-in particular, heteronuclear 2D spectroscopy is often much less sensitive than 1D NMR. One factor contributing to this low sensitivity in 13C/1H heteronuclear NMR is the low natural abundance of the 13C stable isotope; as a consequence, where it is possible to label biological material with 13C, there is a potential enhancement of sensitivity of up to around 90fold. However, there are some problems that can reduce the advantages otherwise gained-in particular, the fine structure arising from 13C/13C coupling, which is essentially non-existent at natural abundance, can reduce the possible sensitivity gain and increase the chances of peak overlap. Here, we examined the use of two different heteronuclear single quantum coherence (HSQC) pulse sequences for the analysis of fully 13C-labeled tissue extracts from Caenorhabditis elegans nematodes. The constant time ct-HSQC had improved peak shape, and consequent better peak detection of metabolites from a labeled extract; matching this against reference spectra from the HMDB gave a match to about 300 records (although fewer actual metabolites, as some of these represent false positive matches). This approach gives a rapid and automated initial metabolome assignment, forming an ideal basis for further manual curation.
RESUMO
BACKGROUND: Dietary restriction (DR) results in increased longevity, reduced fecundity and reduced growth in many organisms. Though many studies have examined the effects of DR on longevity and fecundity, few have investigated the effects on growth. RESULTS: Here we use Caenorhabditis elegans to determine the mechanisms that regulate growth under DR. We show that rather than a reduction in cell number, decreased growth in wild type C. elegans under DR is correlated with lower levels of hypodermal polyploidization. We also show that mutants lacking wild type sensory ciliated neurons are small, exhibit hypo-polyploidization and more importantly, when grown under DR, reduce their levels of endoreduplication to a lesser extent than wild type, suggesting that these neurons are required for the regulation of hypodermal polyploidization in response to DR. Similarly, we also show that the cGMP-dependent protein kinase EGL-4 and the SMA/MAB signalling pathway regulate polyploidization under DR. CONCLUSION: We show C. elegans is capable of actively responding to food levels to regulate adult ploidy. We suggest this response is dependent on the SMA/MAB signalling pathway.
Assuntos
Caenorhabditis elegans/citologia , Caenorhabditis elegans/crescimento & desenvolvimento , Restrição Calórica , Derme/crescimento & desenvolvimento , Dieta , Poliploidia , Animais , Tamanho Corporal , Proteínas de Caenorhabditis elegans/metabolismo , Cílios/metabolismo , Proteínas Quinases Dependentes de GMP Cíclico/metabolismo , Comportamento Alimentar , Fertilidade , Alimentos , Proteínas de Helminto/metabolismo , Estágios do Ciclo de Vida , Longevidade , Modelos Biológicos , Neurônios/metabolismo , Neuropeptídeos/metabolismo , Fator de Crescimento Transformador beta/metabolismoRESUMO
A properly functioning organism must maintain metabolic homeostasis. Deleterious mutations degrade organismal function, presumably at least in part via effects on metabolic function. Here we present an initial investigation into the mutational structure of the Caenorhabditis elegans metabolome by means of a mutation accumulation experiment. We find that pool sizes of 29 metabolites vary greatly in their vulnerability to mutation, both in terms of the rate of accumulation of genetic variance (the mutational variance, VM) and the rate of change of the trait mean (the mutational bias, ΔM). Strikingly, some metabolites are much more vulnerable to mutation than any other trait previously studied in the same way. Although we cannot statistically assess the strength of mutational correlations between individual metabolites, principal component analysis provides strong evidence that some metabolite pools are genetically correlated, but also that there is substantial scope for independent evolution of different groups of metabolites. Averaged over mutation accumulation lines, PC3 is positively correlated with relative fitness, but a model in which metabolites are uncorrelated with fitness is nearly as good by Akaike's Information Criterion.
Assuntos
Caenorhabditis elegans/genética , Metaboloma/genética , Acúmulo de Mutações , Animais , Caenorhabditis elegans/metabolismo , Aptidão Genética , MutaçãoRESUMO
Species richness is distributed unevenly across the tree of life and this may be influenced by the evolution of novel phenotypes that promote diversification. Viviparity has originated â¼150 times in vertebrates and is considered to be an adaptation to highly variable environments. Likewise, possessing an annual life cycle is common in plants and insects, where it enables the colonization of seasonal environments, but rare in vertebrates. The extent to which these reproductive life-history traits have enhanced diversification and their relative importance in the process remains unknown. We show that convergent evolution of viviparity causes bursts of diversification in fish. We built a phylogenetic tree for Cyprinodontiformes, an order in which both annualism and viviparity have arisen, and reveal that while both traits have evolved multiple times, only viviparity played a major role in shaping the patterns of diversity. These results demonstrate that changes in reproductive life-history strategy can stimulate diversification.