Sex-inducing effects toward planarians widely present among parasitic flatworms

Summary Various parasitic flatworms infect vertebrates for sexual reproduction, often causing devastating diseases in their hosts. Consequently, flatworms are of great socioeconomic and biomedical importance. Although the cessation of parasitic flatworm sexual reproduction is a major target of anti-parasitic drug design, little is known regarding bioactive compounds controlling flatworm sexual maturation. Using the planarian Dugesia ryukyuensis, we observed that sex-inducing substances found in planarians are also widespread in parasitic flatworms, such as monogeneans and flukes (but not in tapeworms). Reverse-phase HPLC analysis revealed the sex-inducing substance(s) eluting around the tryptophan retention time in the fluke Calicophoron calicophorum, consistent with previous studies on the planarian Bipalium nobile, suggesting that the substance(s) is likely conserved among flatworms. Moreover, six of the 18 ovary-inducing substances identified via transcriptome and metabolome analyses are involved in purine metabolism. Our findings provide a basis for understanding and modifying the life cycles of various parasitic flatworms.journal articl

Functional roles of Aves class-specific cis-regulatory elements on macroevolution of bird-specific features

Unlike microevolutionary processes, little is known about the genetic basis of macroevolutionary processes. One of these magnificent examples is the transition from non-avian dinosaurs to birds that has created numerous evolutionary innovations such as self-powered flight and its associated wings with flight feathers. By analysing 48 bird genomes, we identified millions of avian-specific highly conserved elements (ASHCEs) that predominantly (>99%) reside in non-coding regions. Many ASHCEs show differential histone modifications that may participate in regulation of limb development. Comparative embryonic gene expression analyses across tetrapod species suggest ASHCE-associated genes have unique roles in developing avian limbs. In particular, we demonstrate how the ASHCE driven avian-specific expression of gene Sim1 driven by ASHCE may be associated with the evolution and development of flight feathers. Together, these findings demonstrate regulatory roles of ASHCEs in the creation of avian-specific traits, and further highlight the importance of cis-regulatory rewiring during macroevolutionary changes

Development and application of a ray-tracing code integrating with 3D equilibrium mapping in LHD ECH experiments

The central electron temperature has successfully reached up to 7.5 keV in large helical device(LHD) plasmas with a central high-ion temperature of 5 keV and a central electron density of1.3×1019 m−3. This result was obtained by heating with a newly-installed 154 GHz gyrotronand also the optimisation of injection geometry in electron cyclotron heating (ECH). Theoptimisation was carried out by using the ray-tracing code ‘LHDGauss’, which was upgradedto include the rapid post-processing three-dimensional (3D) equilibrium mapping obtainedfrom experiments. For ray-tracing calculations, LHDGauss can automatically read the relevantdata registered in the LHD database after a discharge, such as ECH injection settings (e.g.Gaussian beam parameters, target positions, polarisation and ECH power) and Thomsonscattering diagnostic data along with the 3D equilibrium mapping data. The equilibrium mapof the electron density and temperature profiles are then extrapolated into the region outsidethe last closed flux surface. Mode purity, or the ratio between the ordinary mode and theextraordinary mode, is obtained by calculating the 1D full-wave equation along the directionof the rays from the antenna to the absorption target point. Using the virtual magnetic fluxsurfaces, the effects of the modelled density profiles and the magnetic shear at the peripheralregion with a given polarisation are taken into account. Power deposition profiles calculatedfor each Thomson scattering measurement timing are registered in the LHD database. Theadjustment of the injection settings for the desired deposition profile from the feedbackprovided on a shot-by-shot basis resulted in an effective experimental procedure

Stable sustainment of plasmas with electron internal transport barrier by ECH in the LHD

The long pulse experiments in the Large Helical Device has made progress in sustainment of improved confinement states. It was found that steady-state sustainment of the plasmas with improved confinement at the core region, that is, electron internal transport barrier (e-ITB), was achieved with no significant difficulty. Sustainment of a plasma having e-ITB with the line average electron density ne_ave of 1.1 × 1019 m−3 and the central electron temperature Te0 of ∼3.5 keV for longer than 5 min only with 340 kW ECH power was successfully demonstrated

A Single Sex Pheromone Receptor Determines Chemical Response Specificity of Sexual Behavior in the Silkmoth Bombyx mori

In insects and other animals, intraspecific communication between individuals of the opposite sex is mediated in part by chemical signals called sex pheromones. In most moth species, male moths rely heavily on species-specific sex pheromones emitted by female moths to identify and orient towards an appropriate mating partner among a large number of sympatric insect species. The silkmoth, Bombyx mori, utilizes the simplest possible pheromone system, in which a single pheromone component, (E, Z)-10,12-hexadecadienol (bombykol), is sufficient to elicit full sexual behavior. We have previously shown that the sex pheromone receptor BmOR1 mediates specific detection of bombykol in the antennae of male silkmoths. However, it is unclear whether the sex pheromone receptor is the minimally sufficient determination factor that triggers initiation of orientation behavior towards a potential mate. Using transgenic silkmoths expressing the sex pheromone receptor PxOR1 of the diamondback moth Plutella xylostella in BmOR1-expressing neurons, we show that the selectivity of the sex pheromone receptor determines the chemical response specificity of sexual behavior in the silkmoth. Bombykol receptor neurons expressing PxOR1 responded to its specific ligand, (Z)-11-hexadecenal (Z11-16:Ald), in a dose-dependent manner. Male moths expressing PxOR1 exhibited typical pheromone orientation behavior and copulation attempts in response to Z11-16:Ald and to females of P. xylostella. Transformation of the bombykol receptor neurons had no effect on their projections in the antennal lobe. These results indicate that activation of bombykol receptor neurons alone is sufficient to trigger full sexual behavior. Thus, a single gene defines behavioral selectivity in sex pheromone communication in the silkmoth. Our findings show that a single molecular determinant can not only function as a modulator of behavior but also as an all-or-nothing initiator of a complex species-specific behavioral sequence

Extension of operational regime in high-temperature plasmas and effect of ECRH on ion thermal transport in the LHD

A simultaneous high ion temperature (Ti) and high electron temperature (Te) regime was successfully extended due to an optimized heating scenario in the LHD. Such high-temperature plasmas were realized by the simultaneous formation of an electron internal transport barrier (ITB) and an ion ITB by the combination of high power NBI and ECRH. Although the ion thermal confinement was degraded in the plasma core with an increase of Te/Ti by the on-axis ECRH, it was found that the ion thermal confinement was improved at the plasma edge. The normalized ion thermal diffusivity ${{\chi}_{\text{i}}}/T_{\text{i}}^{1.5}$ at the plasma edge was reduced by 70%. The improvement of the ion thermal confinement at the edge led to an increase in Ti in the entire plasma region, even though the core transport was degraded

Two Types of Etiological Mutation in the Limb-Specific Enhancer of Shh

An enhancer named MFCS1 regulates Sonic hedgehog (Shh) expression in the posterior mesenchyme of limb buds. Several mutations in MFCS1 induce ectopic Shh expression in the anterior limb bud, and these result in preaxial polydactyly (PPD). However, the molecular basis of ectopic Shh expression remains elusive, although some mutations are known to disrupt the negative regulation of Shh expression in the anterior limb bud. Here, we analyzed the molecular mechanism of ectopic Shh expression in PPD including in a mouse mutation—hemimelic extra toes (Hx)—and in other MFCS1 mutations in different species. First, we generated transgenic mouse lines with a LacZ reporter cassette flanked with tandem repeats of 40 bp MFCS1 fragments harboring a mutation. The transgenic mouse line with the Hx-type fragment showed reporter expression exclusively in the anterior, but not in the posterior margins of limb buds. In contrast, no specific LacZ expression was observed in lines carrying the MFCS1 fragment with other mutations. Yeast one-hybrid assays revealed that the msh-like homeodomain protein, MSX1, bound specifically to the Hx sequence of MFCS1. Thus, PPD caused by mutations in MFCS1 has two major types of molecular etiology: loss of a cis-motif for negative regulation of Shh, and acquisition of a new cis-motif binding to a preexisting transcription factor, as represented by the Hx mutation

Two Types of Etiological Mutation in the Limb-Specific Enhancer of Shh

An enhancer named MFCS1 regulates Sonic hedgehog (Shh) expression in the posterior mesenchyme of limb buds. Several mutations in MFCS1 induce ectopic Shh expression in the anterior limb bud, and these result in preaxial polydactyly (PPD). However, the molecular basis of ectopic Shh expression remains elusive, although some mutations are known to disrupt the negative regulation of Shh expression in the anterior limb bud. Here, we analyzed the molecular mechanism of ectopic Shh expression in PPD including in a mouse mutation—hemimelic extra toes (Hx)—and in other MFCS1 mutations in different species. First, we generated transgenic mouse lines with a LacZ reporter cassette flanked with tandem repeats of 40 bp MFCS1 fragments harboring a mutation. The transgenic mouse line with the Hx-type fragment showed reporter expression exclusively in the anterior, but not in the posterior margins of limb buds. In contrast, no specific LacZ expression was observed in lines carrying the MFCS1 fragment with other mutations. Yeast one-hybrid assays revealed that the msh-like homeodomain protein, MSX1, bound specifically to the Hx sequence of MFCS1. Thus, PPD caused by mutations in MFCS1 has two major types of molecular etiology: loss of a cis-motif for negative regulation of Shh, and acquisition of a new cis-motif binding to a preexisting transcription factor, as represented by the Hx mutation