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1.
Journal of Ethology - Expelling indigestible objectives through the cloaca is an important cleansing behaviour for several species of higher vertebrates. Although intestinal eversions are short in... 相似文献
2.
Dusan Racko Fabrizio Benedetti Julien Dorier Yannis Burnier Andrzej Stasiak 《Nucleic acids research》2015,43(15):7229-7236
Due to the helical structure of DNA the process of DNA replication is topologically complex. Freshly replicated DNA molecules are catenated with each other and are frequently knotted. For proper functioning of DNA it is necessary to remove all of these entanglements. This is done by DNA topoisomerases that pass DNA segments through each other. However, it has been a riddle how DNA topoisomerases select the sites of their action. In highly crowded DNA in living cells random passages between contacting segments would only increase the extent of entanglement. Using molecular dynamics simulations we observed that in actively supercoiled DNA molecules the entanglements resulting from DNA knotting or catenation spontaneously approach sites of nicks and gaps in the DNA. Type I topoisomerases, that preferentially act at sites of nick and gaps, are thus naturally provided with DNA–DNA juxtapositions where a passage results in an error-free DNA unknotting or DNA decatenation. 相似文献
3.
Andr Scholich Simon Syga Hernn Morales-Navarrete Fabin Segovia-Miranda Hidenori Nonaka Kirstin Meyer Walter de Back Lutz Brusch Yannis Kalaidzidis Marino Zerial Frank Jülicher Benjamin M. Friedrich 《PLoS computational biology》2020,16(12)
How epithelial cells coordinate their polarity to form functional tissues is an open question in cell biology. Here, we characterize a unique type of polarity found in liver tissue, nematic cell polarity, which is different from vectorial cell polarity in simple, sheet-like epithelia. We propose a conceptual and algorithmic framework to characterize complex patterns of polarity proteins on the surface of a cell in terms of a multipole expansion. To rigorously quantify previously observed tissue-level patterns of nematic cell polarity (Morales-Navarrete et al., eLife 2019), we introduce the concept of co-orientational order parameters, which generalize the known biaxial order parameters of the theory of liquid crystals. Applying these concepts to three-dimensional reconstructions of single cells from high-resolution imaging data of mouse liver tissue, we show that the axes of nematic cell polarity of hepatocytes exhibit local coordination and are aligned with the biaxially anisotropic sinusoidal network for blood transport. Our study characterizes liver tissue as a biological example of a biaxial liquid crystal. The general methodology developed here could be applied to other tissues and in-vitro organoids. 相似文献
4.
Yannis P. Papastamatiou Brad M. Wetherbee John O’Sullivan Gwen D. Goodmanlowe Christopher G. Lowe 《Environmental Biology of Fishes》2010,88(4):361-368
The Cookiecutter Shark (Isistius brasiliensis) is an ecto-parasitic predator of numerous large pelagic fish and mammals. However, little is known of its foraging ecology
due to its elusive foraging tactics in the pelagic environment. We used bite scar patterns on pelagic fishes landed at the
Honolulu Fish Auction to assess some of the Cookiecutter Shark foraging habits. Swordfish (Xiphias gladius) had the greatest percentage of bites (87.9 ± 25.0% of individuals had healed scars) followed by Opah (Lampris guttatus, 33.0 ± 8.3% of individuals). Most fish with scars only had one Cookiecutter Shark bite per individual with the exception
of Swordfish, which often had >5 bites per individual. Furthermore, Swordfish had a higher proportion of healed bite scars
meaning they had been attacked while free-swimming. Seasonal changes in the probability of hooked fish being bitten by sharks
were apparent for Swordfish, Bigeye Tuna and Opah. Based on bite scar diameter, larger Cookiecutter Sharks may preferentially
attack Swordfish rather than the other species of pelagic fish. When taken in conjunction with diving behavior of pelagic
fish, and fishing depths, the results add further support to the hypothesis that Cookiecutter Sharks perform diel vertical
migrations. 相似文献
5.
Céline Faugeron Jean-Claude Mollet Yannis Karamanos Henri Morvan 《Acta Physiologiae Plantarum》2006,28(6):557-565
Activities of two de-N-glycosylation enzymes, PNGase (peptide N
4(N-acetyl-glucosaminyl)asparagine amidase) and ENGase (endo N-acetyl-β-D-glucosaminidase), involved in the release of N-glycans from N-glycoproteins, were monitored in several organs of tomato plants (Lycopersicon esculentum, Mill., cv. Dombito) with a fluorescence-HPLC procedure using a resofurin-labelled N-glycopeptide substrate. PNGase and ENGase
activities were detected in every organ assayed but with quantitative differences. The highest activities were found in the
youngest parts of the plant, i.e. apical buds, flowers and leaf blades. PNGase activities were consistently higher than ENGase
activities (three-fold in average). Both de-N-glycosylation activities were associated with high levels of proteins and protease activities. During fruit growth and ripening,
these three parameters decreased notably. The ubiquitous detection of these enzyme activities in the different organs is probably
associated with the previously characterized unconjugated N-glycans in tomato. The possible role of PNGase and ENGase degradation
products (i.e. unconjugated N-glycans) are discussed in relation with their biological functions in plant development. 相似文献
6.
A minimum of 20 porbeagles Lamna nasus were observed circling the Alba oil platform (UK North Sea) over several days in July 2014. Although schools of fish often aggregate around oil platforms, less is known about their ability to aggregate pelagic sharks and L. nasus are rarely seen at the surface. This unusual observation provides new insights into L. nasus behaviour and habitat use and the potential role of offshore artificial structures on pelagic predators. 相似文献
7.
Florian Villegas Daphné Lehalle Daniela Mayer Melanie Rittirsch Michael B. Stadler Marietta Zinner Daniel Olivieri Pierre Vabres Laurence Duplomb-Jego Eveline S.J.M. De Bont Yannis Duffourd Floor Duijkers Magali Avila David Geneviève Nada Houcinat Thibaud Jouan Paul Kuentz Klaske D. Lichtenbelt Joerg Betschinger 《Cell Stem Cell》2019,24(2):257-270.e8
8.
Marieke De Craemer Mina Lateva Violeta Iotova Ellen De Decker Ma?té Verloigne Ilse De Bourdeaudhuij Odysseas Androutsos Piotr Socha Zbigniew Kulaga Luis Moreno Berthold Koletzko Yannis Manios Greet Cardon the ToyBox-study group 《PloS one》2015,10(3)
Background
The aim of the current study was to compare levels of energy balance-related behaviours (physical activity, sedentary behaviour, and dietary behaviours (more specifically water consumption, sugar-sweetened beverage consumption and unhealthy snacking)) in four- to six-year-old preschoolers from six European countries (Belgium, Bulgaria, Germany, Greece, Poland, and Spain) within the ToyBox cross-sectional study.Methods
A sample of 4,045 preschoolers (4.77 ± 0.43 years; 52.2% boys) had valid physical activity data (steps per day), parents of 8,117 preschoolers (4.78 ± 0.46 years; 53.0% boys) completed a parental questionnaire with questions on sedentary behaviours (television viewing, computer use, and quiet play), and parents of 7,244 preschoolers (4.77 ± 0.44 years; 52.0% boys) completed a food frequency questionnaire with questions on water consumption, sugar-sweetened beverage consumption and unhealthy snacking.Results
The highest levels of physical activity were found in Spain (12,669 steps/day on weekdays), while the lowest levels were found in Bulgaria and Greece (9,777 and 9,656 steps/day on weekdays, respectively). German preschoolers spent the least amount of time in television viewing (43.3 min/day on weekdays), while Greek preschoolers spent the most time in television viewing (88.5 min/day on weekdays). A considerable amount of time was spent in quiet play in all countries, with the highest levels in Poland (104.9 min/day on weekdays), and the lowest levels in Spain (60.4 min/day on weekdays). Belgian, German, and Polish preschoolers had the lowest intakes of water and the highest intakes of sugar-sweetened beverages. The intake of snacks was the highest in Belgian preschoolers (73.1 g/day) and the lowest in Greek preschoolers (53.3 g/day).Conclusions
Across six European countries, differences in preschoolers’ energy balance-related behaviours were found. Future interventions should target European preschoolers’ energy balance-related behaviours simultaneously, but should apply country-specific adaptations. 相似文献9.
Idoia Labayen Jonatan R. Ruiz Inge Huybrechts Francisco B. Ortega Manuel Castillo Michael Sjöstrom Marcela González-Gross Yannis Manios Kurt Widhalm Anthony Kafatos Christina Breidenassel Gerardo Rodríguez Jean Dallongeville Frédéric Gottrand Luis A. Moreno 《Journal of physiology and biochemistry》2017,73(2):225-234
There is an increasing interest for the role of liver enzymes as predictors of non-liver-related morbidity and mortality. The American Heart Association (AHA) described the ideal cardiovascular health concept as a score of seven cardiovascular health behaviors and factors that can be used to monitor and predict ideal cardiovascular health over time. This study aimed to examine the association of the ideal cardiovascular health (ICH), as defined by the AHA, with liver enzyme levels in European adolescents. A total of 637 adolescents (54.6% females), aged 14.6 ± 1.2 years from nine European countries participated in this cross-sectional study. Blood levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyltransferase were measured and the AST/ALT ratio calculated. Ideal cardiovascular health was defined as meeting ideal levels of the following components: four behaviors (smoking, body mass index, physical activity, and diet) and three factors (total cholesterol, blood pressure, and glucose). A higher number of ideal cardiovascular health behaviors, factors, and ideal cardiovascular health index were associated with lower ALT (P < 0.05, P < 0.001, and P < 0.001, respectively) and gamma-glutamyltransferase (P < 0.001, P < 0.01, and P < 0.001, respectively) levels. Similarly, a higher number of ideal cardiovascular health behaviors (P < 0.01), factors (P < 0.01), and ideal cardiovascular health index (P < 0.001) were associated with a higher aspartate aminotransferase to alanine aminotransferase ratio. These findings reinforce the usefulness of the ICH index as an instrument to identify target individuals and promote cardiovascular health in adolescents, and it also extends these observations to the liver manifestation of the metabolic syndrome. 相似文献
10.
M.S. Fountoulakis S. Terzakis N. Kalogerakis T. Manios 《Ecological Engineering》2009,35(12):1702-1709
Removal efficiencies of polycyclic aromatic compounds (PAHs) and linear alkyl benzene sulfonates (LAS) were evaluated in a pilot-scale constructed wetland (CW) system combining a free water surface wetland, a subsurface wetland and a gravel filter in parallel. The effect of parameters such as temperature and mass loading rate was also examined. The subsurface constructed wetland system was found to have the overall best performance on pollutants removal. In particular, the average removal of PAHs and LAS was 79.2% and 55.5% for the SSF (Subsurface Flow) constructed wetland, 68.2% and 30.0% for the FWS (Free Water Surface) constructed wetland and 73.3% and 40.9% for the gravel filter, respectively. Removal efficiency and the estimated first-order volumetric removal rate constant (kv) for both PAHs and LAS decreased with increasing water temperature. The experimental results suggest that the absorption in solid media is the main mechanism for xenobiotics removal in constructed wetlands and that the overall performance of the SSF wetland is significantly better than the FWS wetland or the gravel filter. 相似文献