Comptes Rendus Biologies (CR BIOL)

Publications in this journal

• Article: Sexual size dimorphism in the ontogeny of the solitary predatory wasp Symmorphus allobrogus (Hymenoptera: Vespidae)

  Budrienė A, Budrys E, Nevronytė Ž
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  ABSTRACT: Sex-specific patterns of individual growth, resulting in sexual size dimorphism (SSD), are a little studied aspect of the ontogeny related to the evolutionary history and affected by the ecology of a species. We used empirical data on the development of the predatory wasp Symmorphus allobrogus (Hymenoptera, Vespidae) to test the hypotheses that sexual differences of growth resulting in the female-biased SSD embrace the difference in (1) the egg size and the starting size of larva, (2) the larval development duration, and (3) the larval growth rate. We found that eggs developing into males and females have significant differences in size. There was no significant difference between the sexes in the duration of larval development. The relative growth rate and the food assimilation efficiency of female larvae were significantly higher than compared to those of male larvae. Thus, the SSD of S. allobrogus is mediated mainly by sexual differences in egg size and larval growth rate.
  Comptes Rendus Biologies 04/2013; 336(2):57-64.
• Article: The different breeding strategies of penguins: a review

  André Ancel, Michaël Beaulieu, Caroline Gilbert
  Comptes Rendus Biologies 01/2013; 336:1-12.
• Article: Effort d’échantillonnage et atlas floristiques – exhaustivité des mailles et caractérisation des lacunes dans la connaissance

  Jeanne Vallet, Maëlle Rambaud, Loïc Coquel, Laurent Poncet, Frédéric Hendoux
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  ABSTRACT: Résumé Les atlas floristiques sont des outils centraux pour les politiques de conservation de la flore même si l’effort d’échantillonnage est rarement homogène sur les territoires concernés. Ce travail vise à développer une méthode pour estimer le taux d’exhaustivité des unités géographiques d’échantillonnage d’atlas floristiques. Il propose également un outil d’aide à la prospection pour parer à l’hétérogénéité de l’effort d’échantillonnage et optimiser l’efficacité de nouveaux inventaires. Une synthèse bibliographique couplée à des tests sur un jeu de données a abouti au choix d’un estimateur non paramétrique, le Jackknife 1, pour estimer la richesse réelle des unités géographiques d’échantillonnage. Le nombre de données de chaque unité géographique d’échantillonnage est utilisé comme estimateur de l’effort d’échantillonnage. Le rapport entre la richesse observée et cette richesse estimée donne le taux d’exhaustivité de l’inventaire de chaque unité géographique d’échantillonnage. Dix-huit variables ont ensuite été sélectionnées pour décrire les inventaires et orienter les futures prospections ; ces variables renseignent les localisations, les périodes et les espèces à privilégier pour de futurs inventaires. Abstract Floristic atlases have an important input to flora conservation planning even though their data quality varied greatly across countries. This study aimed to assess survey completeness of cells of floristic atlases. Then, a surveying guide is designed to overcome as efficiently as possible sampling biases. A review and analyses on a wide dataset were carried out to select an estimator of the true species richness of surveyed cells. The Jackknife 1, a non-parametric estimator, appeared as the best compromise for regional floristic atlases. The number of records in each cell was used as an estimator of sampling effort. The ratio between the observed species richness and the estimated species richness measures the completeness of inventories in each surveyed cell. Eighteen variables were selected to describe current inventories and design new surveys. These variables highlight locations, periods and species to be given priority in future studies.
  Comptes Rendus Biologies 12/2012; 335(12):753-763.
• Article: Epigenetics, an emerging discipline with broad implications.

  Robert Feil
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  ABSTRACT: The field of epigenetics is young and quickly expanding. During the last year alone, thousands of research articles considered epigenetic mechanisms and their phenotypic consequences in different animal and plant species. Various definitions have been given, though, as to what precisely is epigenetics. Recent ones take into consideration that chromatin at genes and chromosomal regions can be structurally organised by covalent modifications and nuclear proteins, and via RNA molecules, in order to achieve defined expression states that can be perpetuated. Such somatically and meiotically heritable effects on gene function have diverse biological and medical implications. In particular, they are known to be important in development. A recent discussion meeting in Paris at the French Academy of Sciences reviewed our current understanding of 'Epigenetics and Cellular Memory' and where this novel discipline in life sciences is heading.
  Comptes Rendus Biologies 12/2008; 331(11):837-43.
• Article: Influence of biological, environmental and technical factors on phenolic content and antioxidant activities of Tunisian halophytes.

  Riadh Ksouri, Wided Megdiche, Hanen Falleh, Nejla Trabelsi, Mondher Boulaaba, Abderrazak Smaoui, Chedly Abdelly
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  ABSTRACT: Halophyte ability to withstand salt-triggered oxidative stress is governed by multiple biochemical mechanisms that facilitate retention and/or acquisition of water, protect chloroplast functioning, and maintain ion homeostasis. Most essential traits include the synthesis of osmolytes, specific proteins, and antioxidant molecules. This might explain the utilization of some halophytes as traditional medicinal and dietary plants. The present study aimed at assessing the phenolic content and antioxidant activities of some Tunisian halophytes (Cakile maritima, Limoniastrum monopetalum, Mesembryanthemum crystallinum, M. edule, Salsola kali, and Tamarix gallica), depending on biological (species, organ and developmental stage), environmental, and technical (extraction solvent) factors. The total polyphenol contents and antioxidant activities (DPPH and superoxide radicals scavenging activities, and iron chelating and reducing powers) were strongly affected by the above-cited factors. Such variability might be of great importance in terms of valorising these halophytes as a source of naturally secondary metabolites, and the methods for phenolic and antioxidant production.
  Comptes Rendus Biologies 12/2008; 331(11):865-73.
• Article: Identification of new molecules extracted from Quercus suber L. cork.

  Corinne Coquet, Elisée Ferré, Dominique Peyronel, Claude Dal Farra, Anne Marie Farnet
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  ABSTRACT: Various methods of suberin extraction have been used in order to identify monomers of this complex polymer. Pre-extraction of waxes has allowed us to identify for the first time 3-friedelanol as a terpen from cork. Moreover, the wax chemical composition found here varied from previous results since cerin was not identified while friedelin and betulin were. Three fractions were obtained: a polymeric, a monomeric and a low molecular weight fraction, the last of which has never before been described. 2,6-heptanediol was found to be the main compound of this fraction. Furthermore, depolymerisation at room temperature gives the same yields as those obtained at reflux, defining an easier and cheaper methodology.
  Comptes Rendus Biologies 12/2008; 331(11):853-8.
• Article: [Help yourself, and heaven will help you. Initiatives that society can give to allow aged people to remain included].

  Maurice Tubiana
  Comptes Rendus Biologies 12/2008; 331(11):878-80.
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  Available from: e-monsite.com

  Article: Observations on the life history of Chaerilus philippinus Lourenço & Ythier, 2008 (Scorpiones, Chaerilidae) from the Philippines.

  Wilson R Lourenço, Eric Ythier, John L Cloudsley-Thompson
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  ABSTRACT: Biological observations on Chaerilus philippinus were based on specimens from the region of Appari, North of Luzon in the Philippines. The total duration of embryonic development was estimated as being between 110 to 136 days, while the moults between successive juvenile instars and adulthood took place at ages that averaged 7, 39, 73, 190 and 327 days. These developmental periods are shorter and different from those previously observed among species of non-buthid scorpions. They prove to be rather similar to those observed in buthid scorpions, however. Morphometric growth values of the different instars are similar or smaller than those of other species of scorpions that have been studied. Aspects of maternal care and social behaviour are also commented.
  Comptes Rendus Biologies 12/2008; 331(11):896-900.
• Article: [The phytoclimates of France: probabilistic classification of 1874 bio-indicators of the climate].

  Emmanuel Garbolino, Patrice De Ruffray, Henry Brisse, Gilles Grandjouan
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  ABSTRACT: This article presents a synthesis of the relationships between plants and climates at the scale of France, based on a probabilistic classification of 1874 bio-indicators. This classification defines plants groups that indicate the climate, named phytoclimates, expressing the climatic gradients in France. This classification shows 210 phytoclimatic groups distributed into ten cluster levels. The analysis of the various hierarchical levels shows two main phytoclimates testifying the importance of the marine masses and the altitude. The analysis of the third hierarchical level underlines particular phytoclimates which would not be easily recognizable by only analysing the overlapping of floristic and climatic territories. This classification allows one to select taxa that are indicators of the climate. The distribution monitoring or modeling of these taxa should show the effects of the global change on the ecosystems.
  Comptes Rendus Biologies 12/2008; 331(11):881-95.
• Article: Lead accumulation in the roots of grass pea (Lathyrus sativus L.): a novel plant for phytoremediation systems?

  Judicaëlle Brunet, Anne Repellin, Gilles Varrault, Nancy Terryn, Yasmine Zuily-Fodil
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  ABSTRACT: Eleven day-old grass pea plants (Lathyrus sativus L.) were grown hydroponically for 96 h in the presence of 0.5 mM lead nitrate (Pb(NO(3))(2)). The survival rate was 100%. The mean lead content (measured by ICP-OES) in root tissues was 153 mg Pb g(-1) dry matter. Over three quarters of the lead was not labile. Compared with control plants, lead-exposed plants showed a six-fold, two-fold and three and a half-fold reduction in their root calcium, zinc and copper contents, respectively. Together, these results suggested that Lathyrus sativus L. was tolerant to a deficiency in essential nutrients and able to store large amounts of lead in its root tissues. Therefore, it could be used for the development of new rhizofiltration systems.
  Comptes Rendus Biologies 12/2008; 331(11):859-64.
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  Available from: upm.es

  Article: A fully continuous individual-based model of tumor cell evolution.

  Pablo Gómez-Mourelo, Eva Sánchez, Luis Casasús, Glenn F Webb
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  ABSTRACT: The aim of this work is to develop and study a fully continuous individual-based model (IBM) for cancer tumor invasion into a spatial environment of surrounding tissue. The IBM improves previous spatially discrete models, because it is continuous in all variables (including spatial variables), and thus not constrained to lattice frameworks. The IBM includes four types of individual elements: tumor cells, extracellular macromolecules (MM), a matrix degradative enzyme (MDE), and oxygen. The algorithm underlying the IBM is based on the dynamic interaction of these four elements in the spatial environment, with special consideration of mutation phenotypes. A set of stochastic differential equations is formulated to describe the evolution of the IBM in an equivalent way. The IBM is scaled up to a system of partial differential equations (PDE) representing the limiting behavior of the IBM as the number of cells and molecules approaches infinity. Both models (IBM and PDE) are numerically simulated with two kinds of initial conditions: homogeneous MM distribution and heterogeneous MM distribution. With both kinds of initial MM distributions spatial fingering patterns appear in the tumor growth. The output of both simulations is quite similar.
  Comptes Rendus Biologies 12/2008; 331(11):823-36.
• Article: Seed longevity: survival and maintenance of high germination ability of dry seeds.

  Loïc Rajjou, Isabelle Debeaujon
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  ABSTRACT: The seed constitutes the main vector of plant propagation and it is a critical development stage with many specificities. Seed longevity is a major challenge for the conservation of plant biodiversity and for crop success. Seeds possess a wide range of systems (protection, detoxification, repair) allowing them to survive in the dry state and to preserve a high germination ability. Therefore, the seed system provides an appropriate model to study longevity and aging.
  Comptes Rendus Biologies 11/2008; 331(10):796-805.
• Article: Structure and function of seed lipid-body-associated proteins.

  Zita Purkrtova, Pascale Jolivet, Martine Miquel, Thierry Chardot
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  ABSTRACT: Many organisms among the different kingdoms store reserve lipids in discrete subcellular organelles called lipid bodies. In plants, lipid bodies can be found in seeds but also in fruits (olives, ...), and in leaves (plastoglobules). These organelles protect plant lipid reserves against oxidation and hydrolysis until seed germination and seedling establishment. They can be stabilized by specific structural proteins, namely the oleosins and caleosins, which act as natural emulsifiers. Considering the putative role of some of them in controlling the size of lipid bodies, these proteins may constitute important targets for seed improvement both in term of oil seed yield and optimization of technological processes for extraction of oil and storage proteins. We present here an overview of the data on the structure of these proteins, which are scarce, and sometimes contradictory and on their functional roles.
  Comptes Rendus Biologies 11/2008; 331(10):746-54.
• Article: Determinism of carbon and nitrogen reserve accumulation in legume seeds.

  Nathalie Munier-Jolain, Annabelle Larmure, Christophe Salon
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  ABSTRACT: In legume plants, the determination of individual seed weight is a complex phenomenon that depends on two main factors. The first one corresponds to the number of cotyledon cells, which determines the potential seed weight as the cotyledon cell number is related to seed growth rate during seed filling. Since cell divisions take place between flowering and the beginning of seed filling, any stress occurring before the beginning of seed filling can affect individual seed growth rate (C and N reserve accumulation in seeds), and thus individual seed weights. The second factor concerns carbon and nitrogen supply to the growing seed to support reserve accumulation. Grain legume species produce protein-rich seeds involving high requirement of nitrogen. Since seed growth rate as determined by cotyledon cell number is hardly affected by photoassimilate availability during the filling period, a reduction of photosynthetic activity caused by nitrogen remobilization in leaves (e.g., remobilization of essential proteins involved in photosynthesis) can lead to shorten the duration of the filling period, and by that can provoke a limitation of individual seed weights. Accordingly, any biotic or abiotic stress during seed filling causing a decrease in photosynthetic activity should lead to a reduction of the duration of seed filling.
  Comptes Rendus Biologies 11/2008; 331(10):780-7.