Low Surface Potential with Glycoconjugates Determines Insect Cell Adhesion at Room Temperature

Cell-coupled field-effect transistor (FET) biosensors have attracted considerable attention because of their high sensitivity to biomolecules. The use of insect cells (Sf21) as a core sensor element is advantageous due to their stable adhesion to sensors at room temperature. Although visualization of the insect cell-substrate interface leads to logical amplification of signals, the spatiotemporal processes at the interfaces have not yet been elucidated. We quantitatively monitored the adhesion dynamics of Sf21 using interference reflection microscopy (IRM). Specific adhesion signatures with ring-like patches along the cellular periphery were detected. A combination of zeta potential measurements and lectin staining identified specific glycoconjugates with low electrostatic potentials. The ring-like structures were disrupted after cholesterol depletion, suggesting a raft domain along the cell periphery. Our results indicate dynamic and asymmetric cell adhesion is due to low electrostatic repulsion with fluidic sugar rafts. We envision the logical design of cell-sensor interfaces with an electrical model that accounts for actual adhesion interfaces.Matsuzaki T., Terutsuki D., Sato S., et al. Low Surface Potential with Glycoconjugates Determines Insect Cell Adhesion at Room Temperature. Journal of Physical Chemistry Letters 2022 13(40), 9494-9500. DOI: 10.1021/acs.jpclett.2c01673. Copyright © 2022 American Chemical Society

Sensitivity of the Intensity and Structure of Tropical Cyclones to Tropospheric Stability Conditions

The intensity of tropical cyclones (TCs) is controlled by their environmental conditions. In addition to the sea surface temperature, tropospheric temperature lapse rate and tropopause height are highly variable. This study investigates the sensitivity of the intensity and structure of TCs to environmental static stability with a fixed sea surface temperature by conducting a large ensemble of axisymmetric numerical experiments in which tropopause height and tropospheric temperature lapse rate are systematically changed based on the observed environmental properties for TCs that occurred in the western North Pacific. The results indicate that the intensity of the simulated TCs changes more sharply with the increase in the temperature lapse rate than with the increase in the tropopause height. The increases in the intensity of TCs are 1.3–1.9 m s−1 per 1% change of the lapse rate and 0.1–0.5 m s−1 per 1% change of the tropopause height. With the increase in the intensity of TCs, supergradient wind at low levels and double warm core structures are evident. Specifically, the formation of the warm core at the lower levels is closely tied with the intensification of TCs, and the temperature excess of the lower warm core becomes larger in higher lapse rate cases

Quantitative Estimation of Strong Winds in an Urban District during Typhoon Jebi (2018) by Merging Mesoscale Meteorological and Large-Eddy Simulations

2018年の台風21号による大阪市街地での暴風シミュレーションに成功 --市街地内では瞬間的には毎秒60から70メートルにも迫る暴風が吹いた可能性--. 京都大学プレスリリース. 2019-02-06.An intense tropical cyclone, Typhoon Jebi (2018), landed the central part of Japan and caused severe damages. Quantitative assessment of strong winds in urban districts under typhoon conditions is important to understand the underlying risks. As a preliminary study, we investigate the influences of densely built urban environments on the occurrence of wind gusts in an urban district of Osaka City during Typhoon Jebi by merging mesoscale meteorological and building-resolving large-eddy simulations (LES). With the successful reproduction of the track and intensity of the typhoon in meteorological simulations, the simulated winds at the boundary-layer top of the LES model are used to quantitatively estimate the wind gusts in the urban district. The maximum wind gust in the analysis area of Osaka was estimated as 60-70 m s-1, which is comparable to the wind speed at the height of about 300 m

Molecular cloning of motilin and mechanism of motilin-induced gastrointestinal motility in Japanese quail

Motilin, a peptide hormone produced in the upper intestinal mucosa, plays an important role in the regulation of gastrointestinal (GI) motility. In the present study, we first determined the cDNA and amino acid sequences of motilin in the Japanese quail and studied the distribution of motilin-producing cells in the gastrointestinal tract. We also examined the motilin-induced contractile properties of quail GI tracts using an in vitro organ bath, and then elucidated the mechanisms of motilin-induced contraction in the proventriculus and duodenum of the quail. Mature quail motilin was composed of 22 amino acid residues, which showed high homology with chicken (95.4%), human (72.7%), and dog (72.7%) motilin. Immunohistochemical analysis showed that motilin-immunopositive cells were present in the mucosal layer of the duodenum (23.4 ± 4.6 cells/mm^2), jejunum (15.2 ± 0.8 cells/mm^2), and ileum (2.5 ± 0.7 cells/mm^2), but were not observed in the crop, proventriculus, and colon. In the organ bath study, chicken motilin induced dose-dependent contraction in the proventriculus and small intestine. On the other hand, chicken ghrelin had no effect on contraction in the GI tract. Motilin-induced contraction in the duodenum was not inhibited by atropine, hexamethonium, ritanserin, ondansetron, or tetrodotoxin. However, motilin-induced contractions in the proventriculus were significantly inhibited by atropine and tetrodotoxin. These results suggest that motilin is the major stimulant of GI contraction in quail, as it is in mammals and the site of action of motilin is different between small intestine and proventriculus

Circulating messenger for neuroprotection induced by molecular hydrogen

Molecular hydrogen (H2) showed protection against various kinds of oxidative-stress-related diseases. First, it was reported that the mechanism of therapeutic effects of H2 was antioxidative effect due to inhibition of the most cytotoxic reactive oxygen species, hydroxy radical (•OH). However, after chronic administration of H2 in drinking water, oxidative-stress-induced nerve injury is significantly attenuated even in the absence of H2. It suggests indirect signaling of H2 and gastrointestinal tract is involved. Indirect effects of H2 could be tested by giving H2 water only before nerve injury, as preconditioning. For example, preconditioning of H2 for certain a period (∼7 days) in Parkinson’s disease model mice shows significant neuroprotection. As the mechanism of indirect effect, H2 in drinking water induces ghrelin production and release from the stomach via β1-adrenergic receptor stimulation. Released ghrelin circulates in the body, being transported across the blood–brain barrier, activates its receptor, growth-hormone secretagogue receptor. H2-induced upregulation of ghrelin mRNA is also shown in ghrelin-producing cell line, SG-1. These observations help with understanding the chronic effects of H2 and raise intriguing preventive and therapeutic options using H2.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Identification of pheasant ghrelin and motilin and their actions on contractility of the isolated gastrointestinal tract

Motilin and ghrelin were identified in the pheasant by molecular cloning, and the actions of both peptides on the contractility of gastrointestinal (GI) strips were examined in vitro. Molecular cloning indicated that the deduced amino acid sequences of the pheasant motilin and ghrelin were a 22-amino acid peptide, FVPFFTQSDIQKMQEKERIKGQ, and a 26-amino acid peptide, GSSFLSPAYKNIQQQKDTRKPTGRLH, respectively. In in vitro studies using pheasant GI strips, chicken motilin caused contraction of the proventriculus and small intestine, whereas the crop and colon were insensitive. Human motilin, but not erythromycin, caused contraction of small intestine. Chicken motilin-induced contractions in the proventriculus and ileum were not inhibited by a mammalian motilin receptor antagonist, GM109. Neither atropine (a cholinergic receptor antagonist) nor tetrodotoxin (a neuron blocker) inhibited the responses of chicken motilin in the ileum but both drugs decreased the responses to motilin in the proventriculus, suggesting that the contractile mechanisms of motilin in the proventriculus was neurogenic, different from that of the small intestine (myogenic). On the other hand, chicken and quail ghrelin did not cause contraction in any regions of pheasant GI tract. Since interaction of ghrelin and motilin has been reported in the house musk shrew, interaction of two peptides was examined. The chicken motilin-induced contractions were not modified by ghrelin, and ghrelin also did not cause any contraction under the presence of motilin, suggesting the absence of interaction in both peptides. In conclusion, both the motilin system and ghrelin system are present in the pheasant. Regulation of GI motility by motilin might be common in avian species. However, absence of ghrelin actions in any GI regions suggests the avian species-related difference in regulation of GI contractility by ghrelin

Dataset for: Underlying mechanism of the cyclic migrating motor complex in <i>Suncus murinus</i>: a change in gastrointestinal pH is the key regulator

In the fasted gastrointestinal (GI) tract, a characteristic cyclical rhythmic migrating motor complex (MMC) occurs in an ultradian rhythm, at 90–120 min time intervals, in many species. However, the underlying mechanism directing this ultradian rhythmic MMC pattern is yet to be completely elucidated. Therefore, this study aimed to identify the possible causes or factors that involve in the occurrence of the fasting gastric contractions by using <i>Suncus murinus</i> a small model animal featuring almost the same rhythmic MMC as that found in humans and dogs. We observed that either intraduodenal infusion of saline at pH 8 evoked the strong gastric contraction or continuously lowering duodenal pH to 3-evoked gastric phase II-like and phase III-like contractions, and both strong contractions were essentially abolished by the intravenous administration of MA 2029 (motilin receptor antagonist) and D-Lys3-GHRP6 (ghrelin receptor antagonist) in a vagus-independent manner. Moreover, we observed that the prostaglandin E2-alpha (PGE2-α) and serotonin type 4 (5HT4) receptors play important roles as intermediate molecules in changes in GI pH and motilin release. These results suggest a clear insight mechanism that change in the duodenal pH to alkaline condition is an essential factor for stimulating the endogenous release of motilin and governs the fasting MMC in a vagus-independent manner. . Finally, we believe that the changes in duodenal pH triggered by flowing gastric acid and the release of duodenal bicarbonate through the involvement of PGE2-α and 5HT4 receptor are the key events in the occurrence of the MMC