A laboratory rearing of the Antarctic midge, Belgica antarctica: effect of the temperature and diet and possible seasonal adaptation.

The Tenth Symposium on Polar Science/Ordinary sessions : [OB] Polar Biology, Wed. 4 Dec. / Entrance Hall (1st floor) , National Institute of Polar Researc

Light masking of the circatidal activity rhythm in the mangrove cricket Apteronemobius asahinai

Apteronemobius asahinai shows two rhythms in its locomotor activity. One is the circatidal rhythm, which produces active and inactive phases, and the other is the circadian rhythm, which suppresses the intensity of the activity of the circatidal active phase during the subjective day. In the present study, to reveal whether light suppresses locomotor activity by masking the circatidal rhythm without interfering with the circadian rhythm, we observed the activity under 23-h light–dark cycles before and after RNA interference (RNAi) of the circadian clock gene period (per RNAi), which disrupts the circadian rhythm but not the circatidal rhythm. Hyperactivity just after lights-on and lights-off was observed both before and after per RNAi. However, the activity levels were suppressed in the photophase as compared to the scotophase before per RNAi, but not suppressed in the photophase after per RNAi. Thus, the activity of A. asahinai is not directly suppressed by light

Photoperiodic diapause under the control of circadian clock genes in an insect

<p>Abstract</p> <p>Background</p> <p>Most organisms have evolved a circadian clock in order to anticipate daily environmental changes and many of these organisms are also capable of sophisticated measurement of daylength (photoperiodism) that is used to regulate seasonal events such as diapause, migration and polymorphism. It has been generally accepted that the same elements are involved in both circadian (daily) and seasonal (annual) rhythms because both rely upon daily light-dark cycles. However, as reasonable as this sounds, there remains no conclusive evidence of such a molecular machinery in insects. We have approached this issue by using RNA interference (RNAi) in <it>Riptortus pedestris</it>.</p> <p>Results</p> <p>The cuticle deposition rhythm exhibited the major properties of circadian rhythms, indicating that the rhythm is regulated by a circadian clock. RNAi directed against the circadian clock genes of <it>period </it>and <it>cycle</it>, which are negative and positive regulators in the circadian clock, respectively, disrupted the cuticle deposition rhythm and distinct cuticle layers were produced by these RNAi. Simultaneously, <it>period </it>RNAi caused the insect to avert diapause under a diapause-inducing photoperiod whereas <it>cycle </it>RNAi induced diapause under a diapause-averting photoperiod. The expression patterns of juvenile hormone-regulated genes and the application of juvenile hormone analogue suggested that neither ovarian development itself nor a downstream cascade of juvenile hormone secretion, were disturbed by <it>period </it>and <it>cycle </it>RNAi.</p> <p>Conclusions</p> <p>This study revealed that the circadian clock genes are crucial not only for daily rhythms but also for photoperiodic diapause. RNAi directed against <it>period </it>and <it>cycle </it>had opposite effects not only in the circadian cuticle deposition rhythm but also in the photoperiodic diapause. These RNAi also had opposite effects on juvenile hormone-regulated gene expression. It is still possible that the circadian clock genes pleiotropically affect ovarian development but, based on these results, we suggest that the circadian clock operated by the circadian clock genes, <it>period </it>and <it>cycle</it>, governs seasonal timing as well as the daily rhythms.</p> <p>See Commentary: <url>http://www.biomedcentral.com/1741-7007/8/115</url></p

A mutation in SFTPA1 and pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a fatal disease characterized by scattered fibrotic lesions in the lungs. The pathogenesis and genetic basis of IPF remain poorly understood. Here, we show that a homozygous missense mutation in SFTPA1 caused IPF in a consanguineous Japanese family. The mutation in SFTPA1 disturbed the secretion of SFTPA1 protein. Sftpa1 knock-in (Sftpa1-KI) mice that harbored the same mutation as patients spontaneously developed pulmonary fibrosis that was accelerated by influenza virus infection. Sftpa1-KI mice showed increased necroptosis of alveolar epithelial type II (AEII) cells with phosphorylation of IRE1α leading to JNK-mediated up-regulation of Ripk3. The inhibition of JNK ameliorated pulmonary fibrosis in Sftpa1-KI mice, and overexpression of Ripk3 in Sftpa1-KI mice treated with a JNK inhibitor worsened pulmonary fibrosis. These findings provide new insight into the mechanisms of IPF in which a mutation in SFTPA1 promotes necroptosis of AEII cells through JNK-mediated up-regulation of Ripk3, highlighting the necroptosis pathway as a therapeutic target for IPF

Life history traits of adults and embryos of the Antarctic midge Belgica antarctica

Abstract Although larvae of the Antarctic midge, Belgica antarctica, live for more than 2 years, the adult and embryonic stages are brief and are less well known than the larvae. In this report, we provide additional details of these understudied life stages with laboratory observation on adult emergence, longevity, preoviposition period and embryonic development. Male adults emerged slightly earlier than females, and they also lived longer. More than a half (57 %) of the adults that emerged in the laboratory were males. Females produced only a single egg mass and died within a day after oviposition. Embryonic development required 16 days at 4°C, and prior to hatching, the pharate larvae perform a distinct sequence of behaviors that include drinking and peristaltic movement. We also discuss points that need to be resolved for laboratory propagation of this species

Electromagnetic Fields Produced by Moving Sources in a Curved Beam Pipe

A new geometrical perturbation scheme is developed in order to calculate the electromagnetic fields produced by charged sources in prescribed motion moving in a non-straight perfectly conducting beam pipe. The pipe is regarded as a perturbed infinitely long hollow right-circular cylinder. The perturbation maintains the pipe's circular cross-section while deforming its axis into a planar space-curve with, in general, non-constant curvature. Various charged source models are considered including a charged bunch and an off-axis point particle. In the ultra-relativistic limit this permits a calculation of the longitudinal wake potential in terms of powers of the product of the pipe radius and the arbitrarily varying curvature of the axial space-curve. Analytic expressions to leading order are presented for beam pipes with piecewise defined constant curvature modelling pipes with straight segments linked by circular arcs of finite length. The language of differential forms is used throughout and to illustrate the power of this formalism a pedagogical introduction is developed by deriving the theory ab-initio from Maxwell's equations expressed intrinsically as a differential system on (Minkowski) spacetime.Comment: 43pages, 7figure

Observations and Theoretical Implications of the Large Separation Lensed Quasar SDSS J1004+4112

We study the recently discovered gravitational lens SDSS J1004+4112, the first quasar lensed by a cluster of galaxies. It consists of four images with a maximum separation of 14.62''. The system has been confirmed as a lensed quasar at z=1.734 on the basis of deep imaging and spectroscopic follow-up observations. We present color-magnitude relations for galaxies near the lens plus spectroscopy of three central cluster members, which unambiguously confirm that a cluster at z=0.68 is responsible for the large image separation. We find a wide range of lens models consistent with the data, but they suggest four general conclusions: (1) the brightest cluster galaxy and the center of the cluster potential well appear to be offset by several kpc; (2) the cluster mass distribution must be elongated in the North--South direction, which is consistent with the observed distribution of cluster galaxies; (3) the inference of a large tidal shear (~0.2) suggests significant substructure in the cluster; and (4) enormous uncertainty in the predicted time delays between the images means that measuring the delays would greatly improve constraints on the models. We also compute the probability of such large separation lensing in the SDSS quasar sample, on the basis of the CDM model. The lack of large separation lenses in previous surveys and the discovery of one in SDSS together imply a mass fluctuation normalization \sigma_8=1.0^{+0.4}_{-0.2} (95% CL), if cluster dark matter halos have an inner slope -1.5. Shallower profiles would require higher values of \sigma_8. Although the statistical conclusion might be somewhat dependent on the degree of the complexity of the lens potential, the discovery is consistent with the predictions of the abundance of cluster-scale halos in the CDM scenario. (Abridged)Comment: 21 pages, 24 figures, 5 tables, accepted for publication in Ap

Early effect of oral administration of omeprazole with mosapride as compared with those of omeprazole alone on the intragastric pH

<p>Abstract</p> <p>Background</p> <p>The ideal medication for acid-related diseases should have a rapid onset of action to promote hemostasis and cause efficient resolution of symptoms. The aim of our study was to comparatively investigate the inhibitory effect on gastric acid secretion of a single oral administration of omeprazole plus mosapride with that of omeprazole alone.</p> <p>Methods</p> <p>Ten Helicobacter pylori-negative male subjects participated in this randomized, two-way crossover study. Intragastric pH was monitored continuously for 6 hours after a single oral administration of omeprazole 20 mg or that of omeprazole 20 mg plus mosapride 5 mg (the omeprazole being administered one hour after the mosapride). Each administration was separated by a 7-days washout period.</p> <p>Results</p> <p>The average pH during the 6-hour period after administration of omeprazole 20 mg plus mosapride 5 mg was higher than that after administration of omeprazole 20 mg alone (median: 3.22 versus 4.21, respectively; <it>p </it>= 0.0247).</p> <p>Conclusions</p> <p>In H. pylori -negative healthy male subjects, an oral dose of omeprazole 20 mg plus mosapride 5 mg increased the intragastric pH more rapidly than omeprazole 20 mg alone.</p

Net Charge Fluctuations in Au + Au Interactions at sqrt(s_NN) = 130 GeV

Data from Au + Au interactions at sqrt(s_NN) = 130 GeV, obtained with the PHENIX detector at RHIC, are used to investigate local net charge fluctuations among particles produced near mid-rapidity. According to recent suggestions, such fluctuations may carry information from the Quark Gluon Plasma. This analysis shows that the fluctuations are dominated by a stochastic distribution of particles, but are also sensitive to other effects, like global charge conservation and resonance decays.Comment: 6 pages, RevTeX 3, 3 figures, 307 authors, submitted to Phys. Rev. Lett. on 21 March, 2002. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (will be made) publicly available at http://www.phenix.bnl.gov/phenix/WWW/run/phenix/papers.htm