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Current Biology: CB

Astra S Bryant, Felicitas Ruiz, Spencer S Gang, Michelle L Castelletto, Jacqueline B Lopez, Elissa A Hallem
Skin-penetrating parasitic nematodes infect approximately one billion people worldwide and are a major source of neglected tropical disease [1-6]. Their life cycle includes an infective third-larval (iL3) stage that searches for hosts to infect in a poorly understood process that involves both thermal and olfactory cues. Here, we investigate the temperature-driven behaviors of skin-penetrating iL3s, including the human-parasitic threadworm Strongyloides stercoralis and the human-parasitic hookworm Ancylostoma ceylanicum...
July 3, 2018: Current Biology: CB
Christopher G Wilson, Reuben W Nowell, Timothy G Barraclough
A few metazoan lineages are thought to have persisted for millions of years without sexual reproduction. If so, they would offer important clues to the evolutionary paradox of sex itself [1, 2]. Most "ancient asexuals" are subject to ongoing doubt because extant populations continue to invest in males [3-9]. However, males are famously unknown in bdelloid rotifers, a class of microscopic invertebrates comprising hundreds of species [10-12]. Bdelloid genomes have acquired an unusually high proportion of genes from non-metazoans via horizontal transfer [13-17]...
July 3, 2018: Current Biology: CB
Philippe Cubry, Christine Tranchant-Dubreuil, Anne-Céline Thuillet, Cécile Monat, Marie-Noelle Ndjiondjop, Karine Labadie, Corinne Cruaud, Stefan Engelen, Nora Scarcelli, Bénédicte Rhoné, Concetta Burgarella, Christian Dupuy, Pierre Larmande, Patrick Wincker, Olivier François, François Sabot, Yves Vigouroux
African rice (Oryza glaberrima) was domesticated independently from Asian rice. The geographical origin of its domestication remains elusive. Using 246 new whole-genome sequences, we inferred the cradle of its domestication to be in the Inner Niger Delta. Domestication was preceded by a sharp decline of most wild populations that started more than 10,000 years ago. The wild population collapse occurred during the drying of the Sahara. This finding supports the hypothesis that depletion of wild resources in the Sahara triggered African rice domestication...
July 3, 2018: Current Biology: CB
Edward C Harding, Xiao Yu, Andawei Miao, Nathanael Andrews, Ying Ma, Zhiwen Ye, Leda Lignos, Giulia Miracca, Wei Ba, Raquel Yustos, Alexei L Vyssotski, William Wisden, Nicholas P Franks
Mammals, including humans, prepare for sleep by nesting and/or curling up, creating microclimates of skin warmth. To address whether external warmth induces sleep through defined circuitry, we used c-Fos-dependent activity tagging, which captures populations of activated cells and allows them to be reactivated to test their physiological role. External warming tagged two principal groups of neurons in the median preoptic (MnPO)/medial preoptic (MPO) hypothalamic area. GABA neurons located mainly in MPO produced non-rapid eye movement (NREM) sleep but no body temperature decrease...
July 2, 2018: Current Biology: CB
Dana N Reinemann, Stephen R Norris, Ryoma Ohi, Matthew J Lang
A common mitotic defect observed in cancer cells that possess supernumerary (more than two) centrosomes is multipolar spindle formation [1, 2]. Such structures are resolved into a bipolar geometry by minus-end-directed motor proteins, such as cytoplasmic dynein and the kinesin-14 HSET [3-8]. HSET is also thought to antagonize plus-end-directed kinesin-5 Eg5 to balance spindle forces [4, 5, 7, 9]. However, the biomechanics of this force opposition are unclear, as HSET has previously been defined as a non-processive motor [10-16]...
July 2, 2018: Current Biology: CB
Katherine L Dickerson, James A Ainge, Amanda M Seed
Imagining the future is a powerful tool for making plans and solving problems. It is thought to rely on the episodic system which also underpins remembering a specific past event [1-3]. However, the emergence of episodic future thinking over development and evolution is debated [4-9]. One key source of positive evidence in pre-schoolers and animals is the "spoon test" or item choice test [4, 10], in which participants encounter a problem in one context and then a choice of items in another context, one of which is the solution to the problem...
July 2, 2018: Current Biology: CB
Pan Wang, Kuo-Fu Tseng, Yuan Gao, Michael Cianfrocco, Lijun Guo, Weihong Qiu
Mitotic kinesin-14 homodimers that contain an N-terminal nonmotor microtubule-binding tail contribute to spindle organization by preferentially crosslinking two different spindle microtubules rather than interacting with a single microtubule to generate processive motility. However, the mechanism underlying such selective motility behavior remains poorly understood. Here, we show that when a flexible polypeptide linker is inserted into the coiled-coil central stalk, two homodimeric mitotic kinesin-14s of distinct motility-the processive plus-end-directed KlpA from Aspergillus nidulans [1] and the nonprocessive minus-end-directed Ncd from Drosophila melanogaster [2]-both switch to become processive minus-end-directed motors...
June 30, 2018: Current Biology: CB
Natalia L S Machado, Stephen B G Abbott, Jon M Resch, Lin Zhu, Elda Arrigoni, Bradford B Lowell, Patrick M Fuller, Marco A P Fontes, Clifford B Saper
Stress elicits a variety of autonomic responses, including hyperthermia (stress fever) in humans and animals. In this present study, we investigated the circuit basis for thermogenesis and heat conservation during this response. We first demonstrated the glutamatergic identity of the dorsal hypothalamic area (DHAVglut2 ) neurons that innervate the raphe pallidus nucleus (RPa) to regulate core temperature (Tc) and mediate stress-induced hyperthermia. Then, using chemogenetic and optogenetic methods to manipulate this hypothalamomedullary circuit, we found that activation of DHAVglut2 neurons potently drove an increase in Tc, but surprisingly, stress-induced hyperthermia was only reduced by about one-third when they were inhibited...
June 29, 2018: Current Biology: CB
Erica L Morley, Daniel Robert
When one thinks of airborne organisms, spiders do not usually come to mind. However, these wingless arthropods have been found 4 km up in the sky [1], dispersing hundreds of kilometers [2]. To disperse, spiders "balloon," whereby they climb to the top of a prominence, let out silk, and float away. The prevailing view is that drag forces from light wind allow spiders to become airborne [3], yet ballooning mechanisms are not fully explained by current aerodynamic models [4, 5]. The global atmospheric electric circuit and the resulting atmospheric potential gradient (APG) [6] provide an additional force that has been proposed to explain ballooning [7]...
June 29, 2018: Current Biology: CB
Ricardo Kienitz, Joscha T Schmiedt, Katharine A Shapcott, Kleopatra Kouroupaki, Richard C Saunders, Michael Christoph Schmid
Growing evidence suggests that distributed spatial attention may invoke theta (3-9 Hz) rhythmic sampling processes. The neuronal basis of such attentional sampling is, however, not fully understood. Here we show using array recordings in visual cortical area V4 of two awake macaques that presenting separate visual stimuli to the excitatory center and suppressive surround of neuronal receptive fields (RFs) elicits rhythmic multi-unit activity (MUA) at 3-6 Hz. This neuronal rhythm did not depend on small fixational eye movements...
June 28, 2018: Current Biology: CB
Frank Maixner, Dmitrij Turaev, Amaury Cazenave-Gassiot, Marek Janko, Ben Krause-Kyora, Michael R Hoopmann, Ulrike Kusebauch, Mark Sartain, Gea Guerriero, Niall O'Sullivan, Matthew Teasdale, Giovanna Cipollini, Alice Paladin, Valeria Mattiangeli, Marco Samadelli, Umberto Tecchiati, Andreas Putzer, Mine Palazoglu, John Meissen, Sandra Lösch, Philipp Rausch, John F Baines, Bum Jin Kim, Hyun-Joo An, Paul Gostner, Eduard Egarter-Vigl, Peter Malfertheiner, Andreas Keller, Robert W Stark, Markus Wenk, David Bishop, Daniel G Bradley, Oliver Fiehn, Lars Engstrand, Robert L Moritz, Philip Doble, Andre Franke, Almut Nebel, Klaus Oeggl, Thomas Rattei, Rudolf Grimm, Albert Zink
The history of humankind is marked by the constant adoption of new dietary habits affecting human physiology, metabolism, and even the development of nutrition-related disorders. Despite clear archaeological evidence for the shift from hunter-gatherer lifestyle to agriculture in Neolithic Europe [1], very little information exists on the daily dietary habits of our ancestors. By undertaking a complementary -omics approach combined with microscopy, we analyzed the stomach content of the Iceman, a 5,300-year-old European glacier mummy [2, 3]...
June 28, 2018: Current Biology: CB
Hagar Gelbard-Sagiv, Efrat Magidov, Haggai Sharon, Talma Hendler, Yuval Nir
An identical sensory stimulus may or may not be incorporated into perceptual experience, depending on the behavioral and cognitive state of the organism. What determines whether a sensory stimulus will be perceived? While different behavioral and cognitive states may share a similar profile of electrophysiology, metabolism, and early sensory responses, neuromodulation is often different and therefore may constitute a key mechanism enabling perceptual awareness. Specifically, noradrenaline improves sensory responses, correlates with orienting toward behaviorally relevant stimuli, and is markedly reduced during sleep, while experience is largely "disconnected" from external events...
June 27, 2018: Current Biology: CB
Takaya Oikawa, Yasuhiro Ishimaru, Shintaro Munemasa, Yusuke Takeuchi, Kento Washiyama, Shin Hamamoto, Nobuyuki Yoshikawa, Yoshiyuki Mutara, Nobuyuki Uozumi, Minoru Ueda
The circadian leaf opening and closing (nyctinasty) of Fabaceae has attracted scientists' attention since the era of Charles Darwin. Nyctinastic movement is triggered by the alternate swelling and shrinking of motor cells at the base of the leaf. This, in turn, is facilitated by changing osmotic pressures brought about by ion flow through anion and potassium ion channels. However, key regulatory ion channels and molecular mechanisms remain largely unknown. Here, we identify three key ion channels in mimosoid tree Samanea saman: the slow-type anion channels, SsSLAH1 and SsSLAH3, and the Shaker-type potassium channel, SPORK2...
June 27, 2018: Current Biology: CB
Axel Guskjolen, Justin W Kenney, Juan de la Parra, Bi-Ru Amy Yeung, Sheena A Josselyn, Paul W Frankland
Hippocampus-dependent, event-related memories formed in early infancy in human and non-human animals are rapidly forgotten. Recently we found that high levels of hippocampal neurogenesis contribute to accelerated rates of forgetting during infancy. Here, we ask whether these memories formed in infancy are permanently erased (i.e., storage failure) or become progressively inaccessible with time (i.e., retrieval failure). To do this, we developed an optogenetic strategy that allowed us to permanently express channelrhodopsin-2 (ChR2) in neuronal ensembles that were activated during contextual fear encoding in infant mice...
June 26, 2018: Current Biology: CB
Joyce C M Meiring, Nicole S Bryce, Yao Wang, Manuel H Taft, Dietmar J Manstein, Sydney Liu Lau, Jeffrey Stear, Edna C Hardeman, Peter W Gunning
Tropomyosin proteins form stable coiled-coil dimers that polymerize along the α-helical groove of actin filaments [1]. The actin cytoskeleton consists of both co-polymers of actin and tropomyosin and polymers of tropomyosin-free actin [2]. The fundamental distinction between these two types of filaments is that tropomyosin determines the functional capability of actin filaments in an isoform-dependent manner [3-9]. However, it is unknown what portion of actin filaments are associated with tropomyosin. To address this deficit, we have measured the relative distribution between these two filament populations by quantifying tropomyosin and actin levels in a variety of human cell types, including bone (U2OS); breast epithelial (MCF-10A); transformed breast epithelial (MCF-7); and primary (BJpar), immortalized (BJeH), and Ras-transformed (BJeLR) BJ fibroblasts [10]...
June 22, 2018: Current Biology: CB
Corinne A Tovey, Chloe E Tubman, Eva Hamrud, Zihan Zhu, Anna E Dyas, Andrew N Butterfield, Alex Fyfe, Errin Johnson, Paul T Conduit
Microtubules are essential for various cell processes [1] and are nucleated by multi-protein γ-tubulin ring complexes (γ-TuRCs) at various microtubule organizing centers (MTOCs), including centrosomes [2-6]. Recruitment of γ-TuRCs to different MTOCs at different times influences microtubule array formation, but how this is regulated remains an open question. It also remains unclear whether all γ-TuRCs within the same organism have the same composition and how any potential heterogeneity might influence γ-TuRC recruitment...
June 22, 2018: Current Biology: CB
Masato Inoue, Shigeru Kitazawa
Errors in reaching drive trial-by-trial adaptation to compensate for the error. Parietal association areas are implicated in error coding, but whether the parietal error signals directly drive adaptation remains unknown. We first examined the activity of neurons in areas 5 and 7 while two monkeys performed rapid target reaching to clarify whether and how the parietal error signals drive adaptation in reaching. We introduced random errors using a motor-driven prism device to augment random motor errors in reaching...
June 20, 2018: Current Biology: CB
Immani Swapna, Alfredo Ghezzi, Julia M York, Michael R Markham, D Brent Halling, Ying Lu, Jason R Gallant, Harold H Zakon
Molecular variation contributes to the evolution of adaptive phenotypes, though it is often difficult to understand precisely how. The adaptively significant electric organ discharge behavior of weakly electric fish is the direct result of biophysical membrane properties set by ion channels. Here, we describe a voltage-gated potassium-channel gene in African electric fishes that is under positive selection and highly expressed in the electric organ. The channel produced by this gene shortens electric organ action potentials by activating quickly and at hyperpolarized membrane potentials...
June 19, 2018: Current Biology: CB
Stefan Sassmann, Cecilia Rodrigues, Stephen W Milne, Anja Nenninger, Ellen Allwood, George R Littlejohn, Nicholas J Talbot, Christian Soeller, Brendan Davies, Patrick J Hussey, Michael J Deeks
Cell wall appositions (CWAs) are produced reactively by the plant immune system to arrest microbial invasion through the local inversion of plant cell growth. This process requires the controlled invagination of the plasma membrane (PM) in coordination with the export of barrier material to the volume between the plant PM and cell wall. Plant actin dynamics are essential to this response, but it remains unclear how exocytosis and the cytoskeleton are linked in space and time to form functional CWAs. Here, we show that actin-dependent trafficking to immune response sites of Arabidopsis thaliana delivers membrane-integrated FORMIN4, which in turn contributes to local cytoskeletal dynamics...
June 16, 2018: Current Biology: CB
Maxime J Y Zimmermann, Noora E Nevala, Takeshi Yoshimatsu, Daniel Osorio, Dan-Eric Nilsson, Philipp Berens, Tom Baden
Animal eyes have evolved to process behaviorally important visual information, but how retinas deal with statistical asymmetries in visual space remains poorly understood. Using hyperspectral imaging in the field, in vivo 2-photon imaging of retinal neurons, and anatomy, here we show that larval zebrafish use a highly anisotropic retina to asymmetrically survey their natural visual world. First, different neurons dominate different parts of the eye and are linked to a systematic shift in inner retinal function: above the animal, there is little color in nature, and retinal circuits are largely achromatic...
June 15, 2018: Current Biology: CB
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