2,716 research outputs found
Ecology and evolution of cancer
No full textWhile it is widely acknowledged that intratumor heterogeneity is mostly generated by genomic instability, we propose that genomic instability is only part of a proximate mechanism that maintains intratumor heterogeneity through oncogenic selection. Within tissues and organs, malignant cells achieve greater success by cooperating in the process of tumor construction, rather than by just being in isolation. This process would involve the selection of a bet-hedging strategy during oncogenesis to generate the diversity of cell components needed to build, de novo, such an intricate cooperative system. This process requires sufficient time to generate the diversity of relevant clones, which may explain why solid tumors tend to occur late in life. In liquid environments, opportunities for structurally complex tumors are more limited. This may help explain why cancer cells from liquid tumors generally do not aggregate, are on average less heterogeneous (i.e., low selection for bet-hedging), and can be detrimental early in life (e.g., leukemia). In an evolutionary context, this suggests that the bet-hedging strategy is not only a universal risk-diversification strategy that evolves in the populations which face uncertain future and/or environment, it is also selected when there is a need of building, de novo, cooperative and complex systems
The interface between ecology, evolution, and cancer: More than ever a relevant research direction for both oncologists and ecologists
No full textForty years ago, scientists started to describe the genetic cascade of events leading to cancer as "somatic evolution" (Cairns, 1975; Nowell, 1976). Even if the full relevance of these pioneer papers was not immediately perceived by the scientific community, they paved the way for one of the most stimulating and challenging research directions in the effort to predict cancer emergence, progression, and therapy outcomes. Evolutionary biology has indeed deeply transformed our understanding of cancer, gaining unprecedented international recognition among oncologists in the last decade (Ujvari, Roche & Thomas, 2017a). Nowadays, cancer is widely considered as a pathology that emerges due to clonal evolution and cell competition, Darwinian selection being the driver of cancer cells along selective landscapes, culminating in resistance to immune attack, malignant progression, resistance to therapies, metastasis, and even sometimes contagion between individuals and/or species (Ujvari et al., 2017b; Ujvari, Roche & Thomas,2017a). Thus, as recently proposed by Mel Greaves through paraphrasing Dobzhansky's famous dictum, "nothing in cancer makes sense except in the light of evolution" (Greaves, 2018). This interdisciplinary field of research remains at the moment extremely promising, but it is still in its infancy, and fundamental studies (both theoretical and experimental) are still needed to pursue our understanding of the evolutionary ecology of tumors and of host-tumor interactions. By assembling some of the latest, most exciting results, syntheses, and perspectives relating to the topic Ecology, Evolution and Cancer, our objective with this special issue is to reinforce the construction of a solid base for a balanced approach to cancer research, for oncologists and for ecologists
Ecology and evolution of cancer
No full textNeoplasia has been recorded in the vast majority of metazoans. The frequent occurrence of cancer in multicellular organisms suggests that neoplasia, similar to pathogens/parasites, may have a significant negative impact on host fitness in the wild. This is supported by the fact that wildlife cancers have recently been shown to result in significantly increased levels of mortality and concomitant reduction in fitness. By thorough searches of the available literature we provide a comprehensive and an updated list of cancer prevalence and etiology in the wild. We were, however, unable to find data on nontransmissible cancer prevalence in invertebrates and consequently this chapter focuses on cancer in wild vertebrates. Although single cases of cancer are frequently encountered in the wildlife, we were only able to retrieve robust data on cancer prevalence for 31 vertebrate species (12 fish, 3 amphibians, 2 reptiles, 2 birds, and 12 mammals). Cancer prevalence among these vertebrates ranged from as low as 0.2% observed in Canada geese (Branta canadensis) to more than 50% recorded in both Santa Catalina Island foxes (Urocyon littoralis catalinae) and Cape mountain zebras (Equus zebra zebra). The high prevalence recorded in some vertebrates strongly suggests that cancer in wildlife may indeed carry significant fitness costs. In spite of this, the low number of published comprehensive studies clearly shows that so far cancer in wildlife has received insufficient attention by biologists. We hope that this chapter will act as a catalyst for further studies focusing on the impact of cancer in wild animals. The chapter additionally compares cancer recorded in French zoological parks to those obtained at other zoological parks. Finally, we provide an updated list of cancer recorded as single cases in the wild, as well as in captive animals
Searching for a Cancer-Proof Organism: It’s the Journey That Teaches You About the Destination
No full textDespite an obvious focus of cancer as a medical phenomenon affecting human lifespan, cancer occurs across multicellular life. We argue that cancer research could benefit from moving from considering other species’ cancers as mere models of those of humans to embracing the differences across species, as these dictate the logic of natural selection and its ability to “see” cancer as a relevant problem in an organism’s ecology and life history. Simultaneously, cancer should be incorporated more strongly in evolutionary thinking itself. At the origin of multicellularity, there is a gray zone between offspring production and cancer, and the association between sexual reproduction and a unicellular stage in a metazoan life history could prove interesting in this context. The idea that links sex with possibilities to discard “faulty” products of cell divisions is particularly clear in a basal metazoan, the hydra. In larger species with clearly differentiated tissues, there is much to gain from investigating the coevolution of senescence and cancer robustness: prolonging the lifespan of cell lineages (e.g., via telomerase) can be counterproductive for the lifespan of the entire organism, and organisms that live long and are now miniaturized compared with their ancestors (such as birds) should show great promise as study species
Cancer and loneliness in Drosophila
No full textInternational audienceA recommendation of the preprint: Dawson E, Bailly T, Dos Santos J, Moreno C, Devilliers M, Maroni B, Sueur C, Casali A, Ujvari B, Thomas F, Montagne J, Mery F. 2017. An interaction between cancer progression and social environment in Drosophila. BiorXiv, 143560, ver. 3 of 19th September 2017. doi: 10.1101/14356
The Effect of Linguistic Landscape on Palestinians Language Attitudes towards Hebrew in the West Bank
No full textThis paper reports on an investigation of Palestinians' language attitudes towards Hebrew in the West Bank and the effect that linguistic landscape has on these attitudes. Questionnaires were handed to 121 participants. They were divided into two groups: a control group consisting of 65 young Palestinians living in A Area where Hebrew is absent from the linguistic landscape, and an experimental group consisting of 56 young Palestinians living in Huwwara, a Palestinian village classified as B/C Area where Hebrew is present in the linguistic landscape. It was found that Palestinians living in A Area have negative attitudes towards Hebrew in general as they associate it with the Israeli occupation. On the other hand, residents of Huwwara reported neutral feelings towards Hebrew suggesting that they have developed a sense of tolerance towards it due to its presence on road and shop signs without necessarily knowing the language
Lições de sintaxe do português brasileiro para estrangeiros
No full textEste trabalho se insere no âmbito da Teoria e Análise Linguística, bem como no do Ensino de Português como Língua Adicional, área que vem crescendo constantemente no Brasil, e que necessita, cada vez mais, de estudos destinados a contribuir para essa realidade. A partir da breve – mas significativa – experiência da autora nessa área de docência, foram reunidos sete tópicos gramaticais (a saber, a estrutura da frase, o uso do sistema verbal, as preposições, os artigos, a concordância nominal, uso e colocação dos pronomes oblíquos e o uso dos demonstrativos no português brasileiro), sobre os quais não se encontra material tão consistente destinado àquele público, e foram propostas quatorze lições a eles relacionadas. Dessas quatorze lições, as sete primeiras são destinadas ao aprendiz de Português como Língua Adicional, considerando como principal público alunos de nível intermediário em diante; já as sete últimas são lições correspondentes às primeiras, mas destinadas ao professor da área. Nelas, o profissional encontrará fundamentação e discussão teórica a respeito dos pontos apresentados no material do aluno. Este trabalho, portanto, objetiva trazer um material relacionado à descrição sintática do português brasileiro, mas aplicado à área de ensino de Português como Língua Adicional.This work is not only inserted in the Linguistic Theory and Analysis field, but also in the Portuguese as an Additional Language area, which is constantly being expanded in Brazil, and in which there is a considerable necessity of academic studies to be done. From the brief but significant experience the author of this work has in this teaching area, it has been selected seven grammatical topics to be developed: the sentence structure, the use of the verbal system, the prepositions, the articles, the nominal agreement, the use and placement of object pronouns and the use of demonstrative pronouns in Brazilian Portuguese. As normally the material found about these topics is not satisfactory to reach those public necessities, we proposed fourteen lessons, considering that the first seven are designed to the students, especially to the intermediate to advanced ones, and the last seven were designed to the teachers of this area. In these lessons, the teacher will find theory discussion about the issues developed in student’s lessons. This work, thus, intends to bring to the interested reader a material related to syntactic description of Brazilian Portuguese, but applied to the Portuguese as an Additional Language teaching area
Evolution of a contagious cancer: epigenetic variation in Devil Facial Tumour Disease
No full textThe emergence of Devil Facial Tumour Disease (DFTD), a highly contagious cancer, is driving Tasmanian devils (Sarcophilus harrisii) to extinction. The cancer is a genetically and chromosomally stable clonal cell line which is transmitted by biting during social interactions. In the present study, we explore the Devil Facial Tumour (DFT) epigenome and the genes involved in DNA methylation homeostasis. We show that tumour cells have similar levels of methylation to peripheral nerves, the tissue from which DFTD originated. We did not observe any strain or region-specific epimutations. However, we revealed a significant increase in hypomethylation in DFT samples over time (p < 0.0001). We propose that loss of methylation is not because of a maintenance deficiency, as an upregulation of DNA methyltransferase 1 gene was observed in tumours compared with nerves (p < 0.005). Instead, we believe that loss of methylation is owing to active demethylation, supported by the temporal increase in MBD2 and MBD4 (p < 0.001). The implications of these changes on disease phenotypes need to be explored. Our work shows that DFTD should not be treated as a static entity, but rather as an evolving parasite with epigenetic plasticity. Understanding the role of epimutations in the evolution of this parasitic cancer will provide unique insights into the role of epigenetic plasticity in cancer evolution and progression in traditional cancers that arise and die with their hosts.Beata Ujvari, Anne-Maree Pearse, Sarah Peck, Collette Harmsen, Robyn Taylor, Stephen Pyecroft, Thomas Madsen, Anthony T. Papenfuss and Katherine Belo
Zercon peltatus Koch 1836
No full text<p> <b> <i>Zercon peltatus</i> Koch</b> , <b>1836</b></p> <p> <i>Zercon peltatus</i> Koch, 1836: 15.</p> <p> <i>Asca peltata</i>.— Oudemans, 1902: 4; Berlese, 1918: 188. <i>Zercon peltatus</i>.— Oudemans, 1936: 371; Christian & Karg, 2008: 73; Ujvari, 2008: 66. <i>Asca peltatus</i>.— Buitendijk, 1945: 309.</p> <p> NOTE: this species has sometimes been placed in the genus <i>Asca</i>, but it is now correctly classified in the Zerconidae (e.g. Ujvari, 2008).</p>Published as part of <i>De Moraes, Gilberto J., Britto, Erika P. J., Mineiro, Jefferson L. De C. & Halliday, Bruce, 2016, Catalogue of the mite families Ascidae Voigts & Oudemans, Blattisociidae Garman and Melicharidae Hirschmann (Acari: Mesostigmata), pp. 1-299 in Zootaxa 4112 (1)</i> on page 250, DOI: 10.11646/zootaxa.4112.1.1, <a href="http://zenodo.org/record/399477">http://zenodo.org/record/399477</a>
Aboriginal kidney care together -improving outcomes now (AKction): Processes, realities and benefits of first nations led research
No full textMini Oral Abstract - General Nephrology - Health Services Research section.Janet Kelly, Rhanee Lester, Melissa Arnold-Ujvari, Bateman Samantha, Denise Champion, Shellander Champion, Penny Clough, Alyssa Cormick, Derek Forbes, Christine Franks, Ramon Gadd, Odette Gibson, Kylie Herman, Lisa Jamieson, Shilpanjali Jesudason, Sherrie Jones, Jared Kartinyeri, Richard Le Leu, Josee Lavoie, Tamara Mackean, Stephen Mcdonald, Brandon O'connor, Kim O'donnell, Trudy Reid, Elizabeth Rix, Lili Simo, Tahlee Stevenson, Marissa Wilso
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