Territory configuration moderates the frequency of extra‐group mating in superb fairy‐wrens

The frequency of extra‐pair paternity (EPP) in socially monogamous birds varies substantially between and within species, but ecological drivers of this variation remain poorly understood. Habitat configuration could influence EPP by moderating access to extra‐pair mates, because species occupying territories in a clustered ‘honeycomb’ configuration have a larger pool of potential extra‐group mates in their immediate neighbourhood than those living in linearly arranged territories (e.g. along narrow strips of riparian or fragmented habitat). We exploited variation in the spatial arrangement of territories due to anthropogenic modification of habitat of the cooperatively breeding superb fairy‐wren Malurus cyaneus to test whether habitat configuration influenced the frequency of EPP. In this species, most paternity is obtained by males outside the social group [extra‐group paternity (EGP)]. We found that the frequency of EGP among groups living in linear strips of roadside vegetation (41% of 44 offspring) was lower than it was for groups living in clustered territories within continuous habitat (59% of 70 offspring). Differences in group size and pair relatedness did not explain differences in EGP associated with territory configuration, although the frequency of EGP was negatively correlated with pair relatedness. Our finding suggests that territory configuration can influence rates of EGP and that anthropogenic habitat fragmentation has the potential to limit access to extra‐pair mates, affecting mating systems and ultimately fitness.     

Predator-Prey Interactions Shape Thermal Patch Use in a Newt Larvae-Dragonfly Nymph Model

Thermal quality and predation risk are considered important factors influencing habitat patch use in ectothermic prey. However, how the predator’s food requirement and the prey’s necessity to avoid predation interact with their respective thermoregulatory strategies remains poorly understood. The recently developed ‘thermal game model’ predicts that in the face of imminent predation, prey should divide their time equally among a range of thermal patches. In contrast, predators should concentrate their hunting activities towards warmer patches. In this study, we test these predictions in a laboratory setup and an artificial environment that mimics more natural conditions. In both cases, we scored thermal patch use of newt larvae (prey) and free-ranging dragonfly nymphs (predators). Similar effects were seen in both settings. The newt larvae spent less time in the warm patch if dragonfly nymphs were present. The patch use of the dragonfly nymphs did not change as a function of prey availability, even when the nymphs were starved prior to the experiment. Our behavioral observations partially corroborate predictions of the thermal game model. In line with asymmetric fitness pay-offs in predator-prey interactions (the ‘life-dinner’ principle), the prey’s thermal strategy is more sensitive to the presence of predators than vice versa.     

Isolation of Reovirus T3D Mutants Capable of Infecting Human Tumor Cells Independent of Junction Adhesion Molecule-A

Mammalian Reovirus is a double-stranded RNA virus with a distinctive preference to replicate in and lyse transformed cells. On that account, Reovirus type 3 Dearing (T3D) is clinically evaluated as oncolytic agent. The therapeutic efficacy of this approach depends in part on the accessibility of the reovirus receptor Junction Adhesion Molecule-A (JAM-A) on the target cells. Here, we describe the isolation and characterization of reovirus T3D mutants that can infect human tumor cells independent of JAM-A. The JAM-A-independent (jin) mutants were isolated on human U118MG glioblastoma cells, which do not express JAM-A. All jin mutants harbour mutations in the S1 segments close to the region that encodes the sialic acid-binding pocket in the shaft of the spike protein. In addition, two of the jin mutants encode spike proteins with a Q336R substitution in their head domain. The jin mutants can productively infect a wide range of cell lines that resist wt reovirus T3D infection, including chicken LMH cells, hamster CHO cells, murine endothelioma cells, human U2OS and STA-ET2.1 cells, but not primary human fibroblasts. The jin-mutants rely on the presence of sialic-acid residues on the cell surface for productive infection, as is evident from wheat germ agglutinin (WGA) inhibition experiments, and from the jin-reovirus resistance of CHO-Lec2 cells, which have a deficiency of sialic-acids on their glycoproteins. The jin mutants may be useful as oncolytic agents for use in tumors in which JAM-A is absent or inaccessible.     

A data-driven model to study utero-ovarian blood flow physiology during pregnancy

In this paper, we describe a mathematical model of the cardiovascular system in human pregnancy. An automated, closed-loop 1D–0D modelling framework was developed, and we demonstrate its efficacy in (1) reproducing measured multi-variate cardiovascular variables (pulse pressure, total peripheral resistance and cardiac output) and (2) providing automated estimates of variables that have not been measured (uterine arterial and venous blood flow, pulse wave velocity, pulsatility index). This is the first model capable of estimating volumetric blood flow to the uterus via the utero-ovarian communicating arteries. It is also the first model capable of capturing wave propagation phenomena in the utero-ovarian circulation, which are important for the accurate estimation of arterial stiffness in contemporary obstetric practice. The model will provide a basis for future studies aiming to elucidate the physiological mechanisms underlying the dynamic properties (changing shapes) of vascular flow waveforms that are observed with advancing gestation. This in turn will facilitate the development of methods for the earlier detection of pathologies that have an influence on vascular structure and behaviour.

     

Contribution of the water-sediment interface to the transformation of biogenic substances: application to nitrogen compounds

Up to now the water-sediment interface (WSI) has not been considered by limnologists and oceanographers as a theoretical frontier between two phases, but as a variable layer comprising the overlying bottom water, the superficial sediment, and the bioturbed sediment. This heterogeneous benthic boundary layer forms a non-equilibrated assemblage of an aqueous phase, a mineral phase influencing the exchanges, and a dissolved gaseous phase regulating biological activity, detrital organic matter present as dissolved or adsorbed compounds and particles, and a living benthic community dominated by microorganisms. Biological activity and the equilibrium between these components are linked to depth, bottom currents, primary production and allochtonous inputs of organic matter. The settling rate of particulate matter in the water column, which depends on both the size and density of particles, is also an important factor. Settled organic matter is broken down mainly by heterotrophic microorganisms. In the first stage, dissolved or particulate matter is depolymerized by exoenzymes linked to the bacterial membrane. Other heterotrophic organisms, like flagellates and ciliates, contribute to the activity of bacterial populations or to a modification of the physical and chemical characteristics of organic matter like macrofauna. Bacterial activity in the WSI is one to two orders of magnitude higher than in overlying bottom water, depending on the density of the bacterial population, on the amount of available organic matter, and on the presence of predators grazing on bacteria and macrofauna and increasing oxygen and dissolved substrates. The WSI is now considered as a sink for particulate matter and biopolymers, and/or as a sink or source for organic monomers and NH₄ ⁺ depending on their concentrations. As a result of its contribution to mineral and organic cycles, the WSI is a crossroad for exchanges between aqueous and sediment layer. During the last decade, intensive work has been performed in this field, but progress has been slow due to the heterogeneity of the layer and the adsorptive properties of the mineral fraction.     

Reversible phosphorylation of tonoplast proteins involves tonoplast-bound calcium-calmodulin-dependent protein kinase(s) and protein phosphatase(s)

In highly purified tonoplast fractions from Acer pseudoplatanus cells, the in vitro reversible phosphorylation of proteins affected only a restricted set of polypeptides. The phosphorylation process has been shown to be dramatically stimulated by calcium via the mediation of calmodulin as the transducer. The protein kinase(s) was totally inhibited by micromolar concentrations of a calmodulin antagonist. Tonoplast appears to be potentially a good experimental system for the evaluation of the effects of protein phosphorylation on membrane properties in plants.Abbreviations CaM calmodulin - EGTA ethylene glycol-bis-(-amino ethylether)N,N,NN-tetraacetate - SDS-PAGE sodium dodecylsulphate polyacrylamide gel electrophoresis - TCA trichloroacetic acid     

Recurrent and novel LDL receptor gene mutations causing heterozygous familial hypercholesterolemia in La Habana

The molecular basis of familial hypercholesterolemia (FH) in three families of Spanish descent from La Habana was investigated by the candidate gene approach. The Arg3500Gln mutation of apolipoprotein B-100 was not found. Identification of low density lipoprotein receptor (LDLR) gene haplotypes segregating with FH guided the characterisation of three point mutations by automated sequencing. One, a Val408Met missense mutation, a founder mutation in Afrikaner FH patients, was recurrent, being associated with a distinct DNA haplotype. The other two, Glu256Lys and Val776Met missense mutations, were novel and modified highly conserved residues. These mutations were absent in normolipidemic subjects and were associated in heterozygous carriers with twice the cholesterol levels observed in noncarriers. Noticeably, cardiovascular complications were rarely observed in older heterozygotes, even in those with the Afrikaner FH-2 mutation. These findings confirm the molecular heterogeneity of LDLR gene mutations causing FH and the variability of their expression across different populations.     

Biocontrol of the Potato Blackleg and Soft Rot Diseases Caused by Dickeya dianthicola

Development of protection tools targeting Dickeya species is an important issue in the potato production. Here, we present the identification and the characterization of novel biocontrol agents. Successive screenings of 10,000 bacterial isolates led us to retain 58 strains that exhibited growth inhibition properties against several Dickeya sp. and/or Pectobacterium sp. pathogens. Most of them belonged to the Pseudomonas and Bacillus genera. In vitro assays revealed a fitness decrease of the tested Dickeya sp. and Pectobacterium sp. pathogens in the presence of the biocontrol agents. In addition, four independent greenhouse assays performed to evaluate the biocontrol bacteria effect on potato plants artificially contaminated with Dickeya dianthicola revealed that a mix of three biocontrol agents, namely, Pseudomonas putida PA14H7 and Pseudomonas fluorescens PA3G8 and PA4C2, repeatedly decreased the severity of blackleg symptoms as well as the transmission of D. dianthicola to the tuber progeny. This work highlights the use of a combination of biocontrol strains as a potential strategy to limit the soft rot and blackleg diseases caused by D. dianthicola on potato plants and tubers.     

Social jetlag affects subjective daytime sleepiness in school-aged children and adolescents: A study using the Japanese version of the Pediatric Daytime Sleepiness Scale (PDSS-J)

The aim of this study was to elucidate the level of daytime sleepiness in Japanese school-aged children and adolescents, and to examine associated factors including sleep loss and social jetlag using the Japanese version of the Pediatric Daytime Sleepiness Scale (PDSS-J). After the linguistic validation of the PDSS-J with a multi-step translation methodology, consisting of forward translation, back translation, expert review and cognitive debriefing interviews, we conducted a psychometric validation for 492 students aged 11–16 years (46.7% boys) of public elementary school, junior high school and high school, using the PDSS-J, the Karolinska Sleepiness Scale (KSS), and bedtimes and wake-up times on school days and free days. Internal consistency (Cronbach’s alpha) of the PDSS-J was 0.77, and the test–retest reliability demonstrated by the intraclass coefficient was 0.88. Multivariate logistic regression analysis revealed that both short sleep duration and social jetlag were identified as factors associated with daytime sleepiness, after adjustment for age and sex. PDSS-J scores were significantly higher in the group with large social jetlag with or without sufficient sleep duration than in the group with sufficient sleep duration and small social jetlag. The PDSS-J is an important tool for assessing daytime sleepiness, given its ease of administration and robust psychometric properties. The impact of not only sleep loss but also social jetlag on daytime sleepiness among school-aged children and adolescents must be fully taken into account.     

Étude Expérimentale des Variations de la Tendance au vol Chez le Criquet PèlerinSchistocerca Gregaria (Forsk), Élevé Isolément Pendant Plusieurs Générations

Résumé Nous avons étudié l'évolution de la tendance au vol de criquets élevés isolément au cours de plusieurs générations! Les vols ont eu lieu dans des enceintes isolées excluant tout stimulus externe à l'obscurité, à la lumière naturelle et à la lumière artificielle.Des vols continus et limités ne s'observent qu'en première génération d'isolement. On observe souvent des séries de très courts vols se succédant très vite. L'expression la plus courante de l'activité de vol est une succession de vols de quelques minutes séparés par des moments de repos de durée voisine. L'activité à la lumière est très faible, comparée à celle exprimée à l'obscurité. Elle varie, comme à l'obscurité, en fonction de la tendance au vol. Chez les deux sexes, celle-ci devient maximum le plus souvent avec la maturité sexuelle. L'activité est plus précoce chez les femelles; elle est aussi supérieure à celle des mâles.L'isolement réduit la tendance au vol de façon déterminante dès la première génération. Les femelles conservent mieux leur tendance au vol au cours des générations d'isolement.

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Summary The flight tendency of locusts reared solitarily for several generations has been studied. Locusts were suspended for two hours every other day from individual roundabouts in isolated enclosures excluding all external stimuli; in darkness, artificial or natural light.The results include all types of locust flights as the best flyers were not selected beforehand. Limited continuous flights only occur during the first generation of solitary locusts. Series of very short flights following one another in rapid succession can often be observed. These series of flights have been called «linked flights». The most usual form of flight activity is a succession of flights each lasting from one to five minutes, separated by rest periods of about the same lenght.Flight activity in light is very low compared with activity in darkness. Natural light inhibits flight much less than artificial light. Flight activity in light as well as in darkness varies according to the individual locust's flight tendency.For both sexes, flight tendency increases to begin with during the first two weeks then becomes irregular or decreases, according to the individual or it's generation. This tendency then increases again and reaches a maximum generally coinciding with sexual maturity. Activity, for both sexes is formed of successive bursts varying in duration and importance. General flight tendency decreases in both sexes after the period corresponding to the first oviposition. Maximum activity is earlier in females than in males. The former possess a superior flight tendency. However there is a certain simultaneity between both sexes during the increase phase of general activity, and the decrease phase caused by ageing.The effect of isolation reaches almost total inhibition as soon as the first generation. Females maintain their flight tendency better throughout all successive generations reared solitarily.