Tip1/CLIP-170 Protein Is Required for Correct Chromosome Poleward Movement in Fission Yeast

The plus-end microtubule binding proteins (+TIPs) play an important role in the regulation of microtubule stability and cell polarity during interphase. In S. pombe, the CLIP-170 like protein Tip1, together with the kinesin Tea2, moves along the microtubules towards their plus ends. Tip1 also requires the EB1 homolog Mal3 to localize to the microtubule tips. Given the requirement for Tip1 for microtubule stability, we have investigated its role during spindle morphogenesis and chromosome movement. Loss of Tip1 affects metaphase plate formation and leads to the activation of the spindle assembly checkpoint. In the absence of Tip1 we also observed the appearance of lagging chromosomes, which do not influence the normal rate of spindle elongation. Our results suggest that S. pombe Tip1/CLIP170 is directly or indirectly required for correct chromosome poleward movement independently of Mal3/EB1

TRY plant trait database – enhanced coverage and open access

Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Evolution bio-physico-chimique des déchets enfouis au Centre de Stockage de Déchets Ultimes du SYDOM du Jura sous l\u27effet de la recirculation des lixiviats

Ce travail de thèse s\u27inscrit dans un programme de recherche ADEME sur la gestion d\u27un Centre de Stockage de Déchets Ultimes, CSDU, en mode bioréacteur. Le projet a été défini afin d\u27évaluer l\u27impact de la recirculation des lixiviats sur les lixiviats et le biogaz et la stabilisation de la fraction organique fermentescible présente dans le massif de déchets. Les travaux de recherche ont consisté tout d\u27abord à développer des tests de laboratoire de simulation des conditions de stockage et à mettre en uvre une méthodologie de caractérisation bio-physico-chimique des déchets ménagers du SYDOM du Jura pour évaluer l\u27influence des facteurs physico-chimiques sur l\u27évolution et la biostabilité de la matière organique. Par ailleurs, une partie des travaux de recherche a été consacrée à l\u27étude sur site. Le taux d\u27humidité des déchets est le principal facteur d\u27influence sur l\u27activité méthanogène. Par ailleurs, la recirculation des lixiviats semble influer sur la mobilisation des éléments solubles vers la phase liquide, favorisant leur contact avec les micro-organismes, avec pour conséquence la stimulation de la production de biogaz. L\u27évolution des caractéristiques bio-physico-chimiques des déchets avant et après incubation confirme ces observations. Les déchets ayant subi une recirculation présentent une biodégradation et une humification avancée par rapport aux déchets sans recirculation. Le suivi réalisé sur le site laisse apparaître de nombreuses fluctuations sur les paramètres liés à la production de biogaz et de lixiviats. Toutefois, les résultats semblent également montrer l\u27influence de la recirculation sur la matière soluble des déchets

Le dessin d’observation comme outil pour faire évoluer les représentations des élèves de cycle 2 : l’exemple d’un élevage de phasmes pour connaître les caractéristiques du monde vivant

This research thesis focuses on written traces in sciences and more particularly on drawing. The drawing mainly used to account for the initial representations, can it also account for the acquisitions of the students. The collection of three drawings made by the students at different times of the sequence, individual exchanges and collective confrontations highlight the interest of the alternation between these individual times where the student structures his thought and collective times of confrontation. which make it possible to shake up representations and "socially" build new knowledge. The primordial place of the spoken word is recalled during this experiment.Ce mémoire de recherche s’intéresse aux traces écrites en sciences et plus particulièrement au dessin. Le dessin principalement utilisé pour rendre compte des représentations initiales, peut-il également rendre compte des acquisitions des élèves. La collecte de trois dessins réalisés par les élèves à différents moments de la séquence, des échanges individuels et des confrontations collectives mettent en évidence l’intérêt de l’alternance entre ces temps individuels où l’élève structure sa pensée et des temps collectifs de confrontation qui permettent de bousculer les représentations et de « socialement » construire de nouvelles connaissances. La place primordiale de l’oral est rappelée au cours de cette expérimentation

Aurora B kinase controls the separation of centromeric and telomeric heterochromatin

International audienc

Evolution bio-physico-chimique des déchets enfouis au Centre de Stackage de Déchets Ultimes du SYDOM du Jura sous l'effet de la recirculation des lixiviats

Ce travail de thèse s'inscrit dans un programme de recherche ADEME sur la gestion d'un Centre de Stockage de Déchets Ultimes, CSDU, en mode bioréacteur. Le projet a été défini afin d'évaluer l'impact de la recirculation des lixiviats sur les lixiviats et le biogaz et la stabilisation de la fraction organique fermentescible présente dans le massif de déchets. Les travaux de recherche ont consisté tout d'abord à développer des tests de laboratoire de simulation des conditions de stockage et à mettre en œuvre une méthodologie de caractérisation bio-physico-chimique des déchets ménagers du SYDOM du Jura pour évaluer l'influence des facteurs physico-chimiques sur l'évolution et la biostabilité de la matière organique. Par ailleurs, une partie des travaux de recherche a été consacrée à l'étude sur site. Le taux d'humidité des déchets est le principal facteur d'influence sur l'activité méthanogène. Par ailleurs, la recirculation des lixiviats semble influer sur la mobilisation des éléments solubles vers la phase liquide, favorisant leur contact avec les micro-organismes, avec pour conséquence la stimulation de la production de biogaz. L'évolution des caractéristiques bio-physico-chimiques des déchets avant et après incubation confirme ces observations. Les déchets ayant subi une recirculation présentent une biodégradation et une humification avancée par rapport aux déchets sans recirculation. Le suivi réalisé sur le site laisse apparaître de nombreuses fluctuations sur les paramètres liés à la production de biogaz et de lixiviats. Toutefois, les résultats semblent également montrer l'influence de la recirculation sur la matière soluble des déchets.The bioreactor landfill is designed to optimize the humidity rate of the waste and the anaerobic biodegradation of the waste organic matter by leachate recirculation. The major interest of leachate recirculation is to increase the gas production rate under controlled moisture content and hence, to reduce the time period of leachate & biogas treatment. In partnership with the SYDOM of Jura and ADEME, leachate recirculation was performed in situ. In the same time, bioreactor cells at laboratory-scale were performed to determine the effect of several physico-chemical factors for the waste biostabilization and to determine the changes in waste organic matter. The bioreactor landfill increase the gas production rate and the waste biodegradation. At pilot with leachate recirculation, organic matter accumulate to much higher level in the leachate. In pilot with leachate recirculation, organic matter is more stable than organic matter of waste in pilot without leachate recycling.VILLEURBANNE-DOC'INSA LYON (692662301) / SudocSudocFranceF

AuroraB prevents chromosome arm separation defects by promoting telomere dispersion and disjunction.

C. Reyes and C. Serrurier contributed equally to this paper.International audienceThe segregation of centromeres and telomeres at mitosis is coordinated at multiple levels to prevent the formation of aneuploid cells, a phenotype frequently observed in cancer. Mitotic instability arises from chromosome segregation defects, giving rise to chromatin bridges at anaphase. Most of these defects are corrected before anaphase onset by a mechanism involving Aurora B kinase, a key regulator of mitosis in a wide range of organisms. Here, we describe a new role for Aurora B in telomere dispersion and disjunction during fission yeast mitosis. Telomere dispersion initiates in metaphase, whereas disjunction takes place in anaphase. Dispersion is promoted by the dissociation of Swi6/HP1 and cohesin Rad21 from telomeres, whereas disjunction occurs at anaphase after the phosphorylation of condensin subunit Cnd2. Strikingly, we demonstrate that deletion of Ccq1, a telomeric shelterin component, rescued cell death after Aurora inhibition by promoting the loading of condensin on chromosome arms. Our findings reveal an essential role for telomeres in chromosome arm segregation

The fission yeast spindle orientation checkpoint: a model that generates tension?

International audienceIn all eukaryotes, the alignment of the mitotic spindle with the axis of cell polarity is essential for accurate chromosome segregation as well as for the establishment of cell fate, and thus morphogenesis, during development. Studies in invertebrates, higher eukaryotes and yeast suggest that astral microtubules interact with the cell cortex to position the spindle. These microtubules are thought to impose pushing or pulling forces on the spindle poles to affect the rotation or movement of the spindle. In the fission yeast model, where cell division is symmetrical, spindle rotation is dependent on the interaction of astral microtubules with the cortical actin cytoskeleton. In these cells, a bub1-dependent mitotic checkpoint, the spindle orientation checkpoint (SOC), is activated when the spindles fail to align with the cell polarity axis. In this paper we review the mechanism that orientates the spindle during mitosis in fission yeast, and discuss the consequences of misorientation on metaphase progression

Sister Kinetochore Recapture in Fission Yeast Occurs by Two Distinct Mechanisms, Both Requiring Dam1 and Klp2

In eukaryotic cells, proper formation of the spindle is necessary for successful cell division. We have studied chromosome recapture in the fission yeast Schizosaccharomyces pombe. We show by live cell analysis that lost kinetochores interact laterally with intranuclear microtubules (INMs) and that both microtubule depolymerization (end-on pulling) and minus-end–directed movement (microtubule sliding) contribute to chromosome retrieval to the spindle pole body (SPB). We find that the minus-end–directed motor Klp2 colocalizes with the kinetochore during its transport to the SPB and contributes to the effectiveness of retrieval by affecting both end-on pulling and lateral sliding. Furthermore, we provide in vivo evidence that Dam1, a component of the DASH complex, also colocalizes with the kinetochore during its transport and is essential for its retrieval by either of these mechanisms. Finally, we find that the position of the unattached kinetochore correlates with the size and orientation of the INMs, suggesting that chromosome recapture may not be a random process