Advertisement
Current Biology
This journal offers authors two options (open access or subscription) to publish research

Feb 08, 2016

Volume 26Issue 3p277-418, R83-R140
Open Archive
On the cover: An ant visits a carnivorous Venus flytrap plant, which lives on nutrient-poor soil and depends on an animal diet. The insect is lured by the flower-like color and fruity scent of the capture organ. Searching for food, the ant touches the trigger hairs on the inner surface of the trap. In this issue, Böhm et al. (pages 286–295) show that the flytrap can “count” the number of times its trigger hairs are stimulated. Once the trigger hairs are touched two times, the trap closes, forming a “green stomach.” The insect, trying to escape its prison, continues to touch-activate the hairs within the trap. These further stimulations signal densely packed red-colored glands to release a lytic enzyme cocktail, digest the victim, and incorporate the nutrients released from the animal food store....
On the cover: An ant visits a carnivorous Venus flytrap plant, which lives on nutrient-poor soil and depends on an animal diet. The insect is lured by the flower-like color and fruity scent of the capture organ. Searching for food, the ant touches the trigger hairs on the inner surface of the trap. In this issue, Böhm et al. (pages 286–295) show that the flytrap can “count” the number of times its trigger hairs are stimulated. Once the trigger hairs are touched two times, the trap closes, forming a “green stomach.” The insect, trying to escape its prison, continues to touch-activate the hairs within the trap. These further stimulations signal densely packed red-colored glands to release a lytic enzyme cocktail, digest the victim, and incorporate the nutrients released from the animal food store.

Magazine

Feature

  • Chimpanzees, our cultured cousins

    • Michael Gross
    Recent research shows that a large number of behavioural elements in chimpanzees are specific to each community. These are passed on through social learning and can thus be described as cultural. As both chimpanzee and bonobo are endangered in the wild, the opportunity to study such cultures in our nearest relatives in their natural habitat is also under threat.

Q & A

  • Liam Dolan

    • Liam Dolan
    Liam Dolan is the head of the plant sciences department at the University of Oxford, where he studies the growth and evolution of plants.

Essay

Quick guide

  • Tickling

    • David A. Leavens,
    • Kim A. Bard
    A quick guide to tickling, a form of laughter-evoking play that can be considered as an index of agency, with a discussion of its taxonomic distribution and its possible relationship to traditional measures of self-recognition.

Primer

  • The nitrogen cycle

    • Lisa Y. Stein,
    • Martin G. Klotz
    Nitrogen is the fourth most abundant element in cellular biomass, and it comprises the majority of Earth’s atmosphere. The interchange between inert dinitrogen gas (N2) in the extant atmosphere and ‘reactive nitrogen’ (those nitrogen compounds that support, or are products of, cellular metabolism and growth) is entirely controlled by microbial activities. This was not the case, however, in the primordial atmosphere, when abiotic reactions likely played a significant role in the inter-transformation of nitrogen oxides.

Correspondences

  • Morbid attraction to leopard urine in Toxoplasma-infected chimpanzees

    • Clémence Poirotte,
    • Peter M. Kappeler,
    • Barthelemy Ngoubangoye,
    • Stéphanie Bourgeois,
    • Maick Moussodji,
    • Marie J.E. Charpentier
    Infection with the parasite Toxoplasma gondii has been shown to modify behavior in experimental animal models. Here, Poirotte et al. find that natural infection of chimpanzees increases their attraction to the urine of a natural predator, the leopard, suggesting that such behavioral modification may favor transmission of the parasite to its obligate host.
  • Divergent evolution of vitamin B9 binding underlies Juno-mediated adhesion of mammalian gametes

    • Ling Han,
    • Kaoru Nishimura,
    • Hamed Sadat Al Hosseini,
    • Enrica Bianchi,
    • Gavin J. Wright,
    • Luca Jovine
    Recent studies have shown that the GPI-anchored glycoprotein Juno is the egg plasma membrane receptor of sperm Izumo1. Here, Han et al. report the crystal structure of Juno and find that its overall fold is similar to that of folate receptors but with important differences in the ligand-binding site.

Dispatches

  • Exercise: Is More Always Better?

    • Diana M. Thomas,
    • Steven B. Heymsfield
    Do greater levels of exercise always promote relatively higher levels of daily energy expenditure and health? Recent studies challenge the traditional assumption that ‘more exercise is better’ by suggesting daily energy expenditure and health plateaus are reached beyond which incremental gains are minimal.
  • Supergenes: The Genomic Architecture of a Bird with Four Sexes

    • Leonardo Campagna
    Supergenes are clusters of physically linked, co-evolving genes that often control complex traits. A new study clarifies the origin and possible fate of a fascinating supergene that determines the coloration and mating behavior of a widespread North American bird.
  • Plant Physiology: Redefining the Enigma of Metabolism in Stomatal Movement

    • Michael R. Blatt
    Stomata open at the leaf epidermis, driven by solute accumulation in the surrounding guard cells. Transmembrane ion transport has long been recognised to contribute to this process. A new study makes it clear that guard cells also metabolise starch to accelerate opening.
  • Neural Plasticity: Dopamine Tunes the Mushroom Body Output Network

    • Scott Waddell
    Two recent studies in Drosophila provide evidence that dopamine can drive synaptic depression and facilitation, supporting models in which learning and the behavioral state of the fly guide behavior by tuning mushroom body output synapses.
  • Bacterial Speciation: Genetic Sweeps in Bacterial Species

    • Frederick M. Cohan
    One theory of bacterial speciation states that bacterial and animal species share the property of cohesion, meaning that diversity within a species is constrained. A new study provides direct evidence that genome-wide sweeps can limit diversity within bacterial species.
  • Plant Reproduction: Self-Incompatibility to Go

    • Alejandro Tovar-Mendez,
    • Bruce McClure
    In a new study Papaver rhoeas (poppy family) self-incompatibility system has been transferred into Arabidopsis thaliana, a distantly related plant with a very different floral structure. The simple poppy self-incompatibility system may finally make it possible to introduce this potentially valuable trait into any plant.
  • Intestinal Stem Cells: Got Calcium?

    • Máté Nászai,
    • Julia B. Cordero
    Calcium ions are well-known intracellular signalling molecules. A new study identifies local cytoplasmic calcium as a central integrator of metabolic and proliferative signals in Drosophila intestinal stem cells.
  • Posttranslational Regulation: A Way to Evolve

    • Rupali Prasad,
    • Yves Barral
    A new study shows that differences in the regulation of lipin can account for the different strategies of nuclear division in two closely related fission yeast species.
  • Plant Breeding: Surprisingly, Less Sex Is Better

    • Peter J. van Dijk,
    • Diana Rigola,
    • Stephen E. Schauer
    Introduction of apomixis, asexual reproduction through seeds, into crop species has the potential to dramatically transform plant breeding. A new study demonstrates that traits can be stably transferred between generations in newly produced apomictic lines, and heralds a breeding revolution needed to increase food production for the growing planet.

Review

  • Fertilization Mechanisms in Flowering Plants

    • Thomas Dresselhaus,
    • Stefanie Sprunck,
    • Gary M. Wessel
    Compared with the animal kingdom, fertilization is particularly complex in flowering plants (angiosperms). Sperm cells of angiosperms have lost their motility and require transportation as a passive cargo by the pollen tube cell to the egg apparatus (egg cell and accessory synergid cells). Sperm cell release from the pollen tube occurs after intensive communication between the pollen tube cell and the receptive synergid, culminating in the lysis of both interaction partners. Following release of the two sperm cells, they interact and fuse with two dimorphic female gametes (the egg and the central cell) forming the major seed components embryo and endosperm, respectively. This process is known as double fertilization. Here, we review the current understanding of the processes of sperm cell reception, gamete interaction, their pre-fertilization activation and fusion, as well as the mechanisms plants use to prevent the fusion of egg cells with multiple sperm cells. The role of Ca2+ is highlighted in these various processes and comparisons are drawn between fertilization mechanisms in flowering plants and other eukaryotes, including mammals.

Articles

  • Nucleation by rRNA Dictates the Precision of Nucleolus Assembly

    • Hanieh Falahati,
    • Bobbie Pelham-Webb,
    • Shelby Blythe,
    • Eric Wieschaus
    Falahati et al. show that the precisely timed assembly of the nucleolus becomes highly variable in the absence of rDNA. Their results indicate that seeding by rRNA can alter the assembly of the nucleolar components from a stochastic nucleation-limited process to a high-precision growth-limited event.
  • The Venus Flytrap Dionaea muscipula Counts Prey-Induced Action Potentials to Induce Sodium Uptake

    • Jennifer Böhm,
    • Sönke Scherzer,
    • Elzbieta Krol,
    • Ines Kreuzer,
    • Katharina von Meyer,
    • Christian Lorey,
    • Thomas D. Mueller,
    • Lana Shabala,
    • Isabel Monte,
    • Roberto Solano,
    • Khaled A.S. Al-Rasheid,
    • Heinz Rennenberg,
    • Sergey Shabala,
    • Erwin Neher,
    • Rainer Hedrich
    Children are able to count at the age of 15–18 months. In this work, Böhm et al. demonstrate that the carnivorous Venus flytrap plant is able to count as well. The leaf tips develop into snap traps, where the number of contacts of the prey with mechano-sensitive trap initiates capturing and processing of the animal victim.
  • CPG2 Recruits Endophilin B2 to the Cytoskeleton for Activity-Dependent Endocytosis of Synaptic Glutamate Receptors

    • Sven Loebrich,
    • Marc Robert Benoit,
    • Jaclyn Aleksandra Konopka,
    • Jeffrey Richard Cottrell,
    • Joanne Gibson,
    • Elly Nedivi
    Loebrich et al. show that CPG2 acts as a structural and functional link between the F-actin cytoskeleton and the endocytic machinery at excitatory postsynaptic sites. They identify a new component of the endocytic complex, EndoB2, as a CPG2 partner required for activity-dependent glutamate receptor endocytosis, a key aspect of synaptic plasticity.
  • The Forebrain Song System Mediates Predictive Call Timing in Female and Male Zebra Finches

    • Jonathan I. Benichov,
    • Sam E. Benezra,
    • Daniela Vallentin,
    • Eitan Globerson,
    • Michael A. Long,
    • Ofer Tchernichovski
    Benichov et al. show that zebra finches predictively adjust the timing of unlearned calls in response to rhythmic call patterns. Female zebra finches, who don’t sing, show better call timing plasticity than males. In both sexes, the forebrain song system is required for this learning, suggesting a role for this circuit in interactive vocal coordination.
  • Nutritional Control of Cell Size by the Greatwall-Endosulfine-PP2A·B55 Pathway

    • Nathalia Chica,
    • Ana Elisa Rozalén,
    • Livia Pérez-Hidalgo,
    • Angela Rubio,
    • Bela Novak,
    • Sergio Moreno
    Cells are large in rich media and small in poor media. Here, Chica et al. show that the greatwall-endosulfine pathway couples the nutritional environment to the cell-cycle machinery by regulating the activity of PP2A·B55. This pathway links cell growth (TORC1) with cell division (Cdk1) and controls cell size homeostasis in fission yeast
  • Apomixis Allows the Transgenerational Fixation of Phenotypes in Hybrid Plants

    • Christian Sailer,
    • Bernhard Schmid,
    • Ueli Grossniklaus
    Permanent genotype fixation by natural cloning (apomixis) is thought to fix complex, agronomically important traits of hybrids. Sailer et al. provide the first empirical proof of principle that complex phenotypes can be fixed across generations by apomixis, thereby demonstrating that apomixis can indeed be used in plant breeding and agriculture.

Reports

  • Motor Skills Are Strengthened through Reconsolidation

    • Nicholas F. Wymbs,
    • Amy J. Bastian,
    • Pablo A. Celnik
    Wymbs et al. demonstrate that motor skill is strengthened during reconsolidation when reactivated within an environment that increases variability but maintains original learning context. Their results provide evidence for how motor skills are strengthened over multiple training sessions via reconsolidation processes.
  • Divergence and Functional Degradation of a Sex Chromosome-like Supergene

    • Elaina M. Tuttle,
    • Alan O. Bergland,
    • Marisa L. Korody,
    • Michael S. Brewer,
    • Daniel J. Newhouse,
    • Patrick Minx,
    • Maria Stager,
    • Adam Betuel,
    • Zachary A. Cheviron,
    • Wesley C. Warren,
    • Rusty A. Gonser,
    • Christopher N. Balakrishnan
    Supergenes are linked clusters of genes that contribute to adaptive variation. The origin and fate of polymorphic supergenes within species are not well understood. To advance the understanding of supergenes, Tuttle et al. examine the origin, evolutionary history, and possible fate of a fitness-related supergene in the white-throated sparrow.
  • Working Memory Systems in the Rat

    • Alexander Bratch,
    • Spencer Kann,
    • Joshua A. Cain,
    • Jie-En Wu,
    • Nilda Rivera-Reyes,
    • Stefan Dalecki,
    • Diana Arman,
    • Austin Dunn,
    • Shiloh Cooper,
    • Hannah E. Corbin,
    • Amanda R. Doyle,
    • Matthew J. Pizzo,
    • Alexandra E. Smith,
    • Jonathon D. Crystal
    Bratch et al. show that olfactory and spatial memory in rats are resistant to interference from the addition of a memory load in the other domain. These studies suggest that rats process information with multiple, independent working memory systems for olfactory and spatial information.
  • Single-Cell Analysis of Growth in Budding Yeast and Bacteria Reveals a Common Size Regulation Strategy

    • Ilya Soifer,
    • Lydia Robert,
    • Ariel Amir
    Soifer et al. study growth of the budding yeast S. cerevisiae at the single-cell level and show that a model in which daughter cells add a constant volume between two budding events quantitatively explains all correlations and distributions of cell-cycle-related variables. Data on E. coli show remarkably similar correlations.
  • Blue Light Induces a Distinct Starch Degradation Pathway in Guard Cells for Stomatal Opening

    • Daniel Horrer,
    • Sabrina Flütsch,
    • Diana Pazmino,
    • Jack S.A. Matthews,
    • Matthias Thalmann,
    • Arianna Nigro,
    • Nathalie Leonhardt,
    • Tracy Lawson,
    • Diana Santelia
    Horrer et al. report quantitative analysis of starch turnover in guard cells of intact Arabidopsis leaves and show it to be an ideal system to study guard cell carbohydrate metabolism. Molecular genetic analyses show that guard cells integrate blue-light-induced proton pumping with starch degradation to control stomatal opening and plant growth.
  • Selective Activation of the Deep Layers of the Human Primary Visual Cortex by Top-Down Feedback

    • Peter Kok,
    • Lauren J. Bains,
    • Tim van Mourik,
    • David G. Norris,
    • Floris P. de Lange
    Using high-field fMRI, Kok et al. show that feedback signals evoked by a visual illusion selectively activate the deep layers of the primary visual cortex, demonstrating the potential for non-invasive in vivo recordings of neural activity with laminar specificity in humans.
  • Signal Use by Octopuses in Agonistic Interactions

    • David Scheel,
    • Peter Godfrey-Smith,
    • Matthew Lawrence
    Cephalopods show complex behaviors, including color changes. Scheel et al. assess the signaling role of body pattern displays by octopuses. Some displays are signals that mediate agonistic interactions. Comparisons of signal behavior among octopus species may provide a model for understanding the ecological factors shaping signal evolution.
  • A 365-Million-Year-Old Freshwater Community Reveals Morphological and Ecological Stasis in Branchiopod Crustaceans

    • Pierre Gueriau,
    • Nicolas Rabet,
    • Gaël Clément,
    • Linda Lagebro,
    • Jean Vannier,
    • Derek E.G. Briggs,
    • Sylvain Charbonnier,
    • Sébastien Olive,
    • Olivier Béthoux
    Gueriau et al. describe a 365-million-year-old ephemeral pool community composed of the earliest modern-looking branchiopod crustaceans. Preservation of drought-resistant eggs illustrates how these animals colonized temporary terrestrial environments, leading to remarkable ecological and morphological stasis that persists to the present day.
  • Robust DNA Methylation in the Clonal Raider Ant Brain

    • Romain Libbrecht,
    • Peter Robert Oxley,
    • Laurent Keller,
    • Daniel Jan Christoph Kronauer
    Libbrecht et al. show that in the clonal raider ant, brain DNA methylation is robust, particularly in genes with high and stable expression, and is not associated with different reproductive and behavioral states. They also report that currently there is little evidence of differential DNA methylation between the female castes of social insects.
  • Local Slow Waves in Superficial Layers of Primary Cortical Areas during REM Sleep

    • Chadd M. Funk,
    • Sakiko Honjoh,
    • Alexander V. Rodriguez,
    • Chiara Cirelli,
    • Giulio Tononi
    During REM sleep, the scalp EEG shows low-voltage fast activity as in wake, yet subjects do not respond to mild stimuli. Funk et al. show that slow waves, a hallmark of NREM sleep, also occur during REM sleep in middle and superficial layers of primary cortices. These slow waves may partly explain the sensory disconnection of REM sleep.
  • Bacterial Autoimmunity Due to a Restriction-Modification System

    • Maroš Pleška,
    • Long Qian,
    • Reiko Okura,
    • Tobias Bergmiller,
    • Yuichi Wakamoto,
    • Edo Kussell,
    • Călin C. Guet
    Restriction-modification (RM) systems protect nearly all prokaryotes from parasitic DNA. Pleška et al. show that a subpopulation of bacteria carrying an RM system suffers from autoimmunity—a stochastic process, which temporarily disrupts the host’s genome integrity.
  • Constrained Total Energy Expenditure and Metabolic Adaptation to Physical Activity in Adult Humans

    • Herman Pontzer,
    • Ramon Durazo-Arvizu,
    • Lara R. Dugas,
    • Jacob Plange-Rhule,
    • Pascal Bovet,
    • Terrence E. Forrester,
    • Estelle V. Lambert,
    • Richard S. Cooper,
    • Dale A. Schoeller,
    • Amy Luke
    Pontzer et al. examine total energy expenditure and physical activity in a large adult human sample. Rather than increasing linearly with physical activity, total energy expenditure plateaus above moderate activity levels, suggesting that the body adapts to higher activity levels to keep total energy expenditure within a relatively narrow range.

Corrections

Advertisement
Advertisement