Photoperiodic gene expression of insulin receptor is associated with diapause regulation in silkworm

Bivoltine silkworms (Bombyx mori) are destined to respectively produce diapause or non-diapause eggs when they are reared under short or long days during the larval stage. The insulin signaling pathway is thought to play an essential role in regulating diapause in various insect species, but its involvement in silkworm diapause programming has not been investigated in detail. Therefore, we examined day-night expression of the insulin receptor (InR) gene in the silkworm larval brain under different photoperiods or in night interruption experiments in which larvae were exposed to light for 2 h during the nighttime of short days. Expression of the InR gene was photoperiod-dependent and InR mRNA levels decreased with increasing daylength. As the daylength increased, expression during the nighttime decreased to lower stable levels earlier than that during the daytime. During night interruptions that induced non-diapause, the nighttime expression of InR decreased to low levels like those during long days, although daytime expression was only moderately decreased. Nighttime InR expression was downregulated in silkworms reared under non-diapause-inducing conditions (long days and night interruptions). In contrast, abundant InR was expressed during the day and night in short days that induced diapause. Our findings suggested that InR expression in the larval brain is associated with programming the diapause status in the next generation of silkworms. Downregulated InR might suppress the insulin signaling pathway and cause non-diapause induction in the next generation. DOI: http://dx.doi.org/10.5281/zenodo.1041315

High-Voltage Methods for Mushroom Fruit-Body Developments

High-voltage electrical stimulation is effective for promotion of fruit-body development in mushroom cultivation. The high voltage applying to cultivation bed of mushroom generates intense electric field inside the bed substrate. The intense electric field accelerates the hypha move owing to the electrostatic force. As a result, some parts of hyphae are cut and scratched. The cutting and scratching of hypha work as stimulation for promotion of the fruit-body development. The promotion effect of high-voltage stimulation to sawdust-based substrate of L. and natural logs hosting Lentinula edodes, Pholiota microspora and Hypholoma lateritium are confirmed through the experiment in the cultivation field. The fruit-body formation of mushrooms increases 1.3–2.0 times in terms of the total weight. The accumulated yield of L. edodes for four cultivation seasons is improved from 160 to 320 g by applying high voltage of 50 or 100 kV. However, the yield decreases from 320 to 240 g upon increasing applied voltage from 100 to 130 kV. The yield of the other types of mushrooms shows tendencies similar to those of L. edodes by applying high voltage. An optimal voltage exists for efficient fruiting body induction

Bilateral diaphragm paralysis after simultaneous cardiac surgery and Nuss procedure in the infant

AbstractThe case of a 15-month-old boy with bilateral diaphragm paralysis after simultaneous cardiac surgery for tetralogy of Fallot, and Nuss procedure for pectus excavatum, is presented. Extubated one day after his first operation, the boy suffered severe respiratory distress soon after, due to bilateral diaphragmatic paralysis. Diaphragm paralysis restricted abdominal respiration, while thoracic respiration was inhibited by metallic bar after the Nuss Procedure, which combined prevented extubation for 47 days. Thoracoplasty, such as the Nuss Procedure, should not be performed simultaneously with cardiac surgery because abdominal and thoracic respiration can be restricted in infants, causing prolonged, severe, post-surgical respiratory failure

Silkworm larvae (Bombyx mori) can learn cues associated with finding food

The present study investigated the ability of silkworm Bombyx mori (Lepidoptera: Bombycidae) larvae to learn. Silkworm larvae were trained to consume food that was placed on red paper; consequently they became attracted to red, rather than blue paper even in the absence of food. In contrast, untrained controls had no preference for either red or blue paper. These results suggested that silkworm larvae learned to associate red paper with food, and that they can discriminate colors. DOI: http://dx.doi.org/10.5281/zenodo.560946

Characterization of β-N-acetylhexosaminidase (LeHex20A), a member of glycoside hydrolase family 20, from Lentinula edodes shiitake mushroom)

We purified and cloned a β-N-acetylhexosaminidase, LeHex20A, with a molecular mass of 79 kDa from the fruiting body of Lentinula edodes (shiitake mushroom). The gene lehex20a gene had 1,659 nucleotides, encoding 553 amino acid residues. Sequence analysis indicated that LeHex20A belongs to glycoside hydrolase (GH) family 20, and homologues of lehex20a are broadly represented in the genomes of basidiomycetes. Purified LeHex20A hydrolyzed the terminal monosaccharide residues of β-N-acetylgalactosaminides and β-N-acetylglucosaminides, indicating that LeHex20A is a β-N-acetylhexosaminidase classified into EC 3.2.1.52. The maximum LeHex20A activity was observed at pH 4.0 and 50°C. The kinetic constants were estimated using chitooligosaccharides with degree of polymerization 2-6. GH20 β-N-acetylhexosaminidases generally prefer chitobiose among natural substrates. However, LeHex20A had the highest catalytic efficiency (k(cat)/K(m)) for chitotetraose, and the K(m) values for GlcNAc(6) were 3.9-fold lower than for chitobiose. Furthermore, the enzyme partially hydrolyzed amorphous chitin polymers. These results indicate that LeHex20A can produce N-acetylglucosamine from long-chain chitomaterials

A computational model of internal representations of chemical gradients in environments for chemotaxis of Caenorhabditis elegans

The small roundworm Caenorhabditis elegans employs two strategies, termed pirouette and weathervane, which are closely related to the internal representation of chemical gradients parallel and perpendicular to the travelling direction, respectively, to perform chemotaxis. These gradients must be calculated from the chemical information obtained at a single point, because the sensory neurons are located close to each other at the nose tip. To formulate the relationship between this sensory input and internal representations of the chemical gradient, this study proposes a simple computational model derived from the directional decomposition of the chemical concentration at the nose tip that can generate internal representations of the chemical gradient. The ability of the computational model was verified by using a chemotaxis simulator that can simulate the body motions of pirouette and weathervane, which confirmed that the computational model enables the conversion of the sensory input and head-bending angles into both types of gradients with high correlations of approximately r > 0.90 (p < 0.01) with the true gradients. In addition, the chemotaxis index of the model was 0.64, which is slightly higher than that in the actual animal (0.57). In addition, simulation using a connectome-based neural network model confirmed that the proposed computational model is implementable in the actual network structure.This work was supported by JSPS KAKENHI Grant Number 15H03950 to T.T and MEXT KAKENHI Grant Numbers 20115010 to T.T. and 20115002 to Y.I

Anuran calcitonins are diverse in lower vertebrates

金沢大学環日本海域環境研究センター生物多様性研究部門We investigated the nucleotide sequences of cDNA fragments coding calcitonin from ultimobranchial glands in 2 species of urodelans (1 salamander and 1 newt) and 4 species of anurans (1 toad and 3 frogs) by the reverse transcription polymerase chain reaction (RT-PCR) method and rapid amplification of cDNA ends (RACE)-PCR method. The salamander and newt calcitonins were each 97% and 94% similar to the lungfish and caiman calcitonins that we have already reported, in the amino acid sequences. However, anuran calcitonins were not only dissimilar (63-81%) to the lungfish and caiman calcitonins but also diversified (59-91%) even among anurans. The sequence identity of toad calcitonin was always low (59-66%) among anurans

Clinical Performance of a Salivary Amylase Activity Monitor During Hemodialysis Treatment

The hemodialysis procedure is thought to be a physical stressor in the majority of hemodialyzed patients. Previous studies suggest that elevated salivary amylase level may correlate with increased plasma norepinephrine level under psychological and physical stress conditions. In this study, we investigated biological stress reactivity during hemodialysis treatment using salivary amylase activity as a biomarker. Seven patients (male/female = 5/2, age: 67.7+/−5.9 years) who had been receiving regular 4 h hemodialysis were recruited. Salivary amylase activity was measured using a portable analyzer every hour during the hemodialysis session. Salivary amylase activity was shown to be relatively stable and constant throughout hemodialysis, whereas there were significant changes in systolic blood pressure and pulse rate associated with blood volume reduction. Our results show that hemodialysis treatment per se dose not affect salivary amylase activity