Apterichtus keramanus, a new snake-eel from Okinawa, southern Japan (Ophichthinae, Ophichthidae)

A new snake-eel,Apterichtus keramanus, is described on the basis of a single 276-mm TL specimen trawled from the coast of Kerama Islands, Okinawa Prefecture, Japan. The species is unique in the genus in having the posterior nostril opening entirely inside the mouth and a dark band running from the anteroventral margin of the eye to the upper lip.     

MiR-376c Down-Regulation Accelerates EGF-Dependent Migration by Targeting GRB2 in the HuCCT1 Human Intrahepatic Cholangiocarcinoma Cell Line

MicroRNA miR-376c was expressed in normal intrahepatic biliary epithelial cells (HIBEpiC), but was significantly suppressed in the HuCCT1 intrahepatic cholangiocarcinoma (ICC) cell line. The biological significance of the down-regulation of miR-376c in HuCCT1 cells is unknown. We hypothesized that miR-376c could function as a tumor suppressor in these cells. To test this hypothesis, we sought the targets of miR-376c, and characterized the effect of its down-regulation on HuCCT1 cells. We performed proteomic analysis of miR-376c-overexpressing HuCCT1 cells to identify candidate targets of miR-376c, and validated these targets by 3′-UTR reporter assay. Transwell migration assays were performed to study the migratory response of HuCCT1 cells to miR-376c overexpression. Furthermore, microarrays were used to identify the signaling that were potentially involved in the miR-376c-modulated migration of HuCCT1. Finally, we assessed epigenetic changes within the potential promoter region of the miR-376c gene in these cells. Proteomic analysis and subsequent validation assays showed that growth factor receptor-bound protein 2 (GRB2) was a direct target of miR-376c. The transwell migration assay revealed that miR-376c significantly reduced epidermal growth factor (EGF)-dependent cell migration in HuCCT1 cells. DNA microarray and subsequent pathway analysis showed that interleukin 1 beta and matrix metallopeptidase 9 were possible participants in EGF-dependent migration of HuCCT1 cells. Bisulfite sequencing showed higher methylation levels of CpG sites upstream of the miR-376c gene in HuCCT1 relative to HIBEpiC cells. Combined treatment with the DNA-demethylating agent 5-aza-2′-deoxycytidine and the histone deacetylase inhibitor trichostatin A significantly upregulated the expression of miR-376c in HuCCT1 cells. We revealed that epigenetic repression of miR-376c accelerated EGF-dependent cell migration through its target GRB2 in HuCCT1 cells. These findings suggest that miR-376c functions as a tumor suppressor. Since metastasis is the major cause of death in ICC, microRNA manipulation could lead to the development of novel anti-cancer therapy strategies for ICC.     

Thermotropic phase behavior and stability of monosialoganglioside micelles in aqueous solution.

The thermotropic phase behavior of monosialoganglioside in a dilute aqueous dispersion at pH 6.8 was measured by using synchrotron radiation small-angle x-ray scattering and was analyzed by a shell-modeling method. Previous calorimetric studies on ganglioside systems have shown quite different thermotropic behaviors from other biological lipid systems, however, the details have still been ambiguous. Because of high statistical data and a shell-modeling analysis, we could elucidate the internal structural change of monosialoganglioside micelle induced by the elevation of temperature from 6 to 60 degrees C, that is, the shrinkage of the hydrophilic region and the slight expansion of the hydrophobic region occurring simultaneously, accompanying the elongation of the axial ratios of the ellipsoidal micelles. The model structures obtained explain the changes in the experimental scattering curves, the distance distribution functions, and the gyration radii. In addition we have also found an evident thermal hysteresis in the scattering curves and in the structural parameters. The present result suggests that the thickness of the hydrophilic region, namely, the conformation of oligosaccharide chains, is sensitive to a change of temperature.     

Chromatic Regulation of Photosystem Composition in the Cyanobacterial Photosynthetic System: Kinetic Relationship between Change of Photosystem Composition and Cell Proliferation

Kinetics of the change of photosystem (PS) composition in cyanobacteriainduced by chromatic light were studied in relation to cellproliferation. The study was made for two unicellular strains,Synechococcus NIBB 1059 and Synechocystis (Aphanocapsa) PCC6714. We found that (1) the change to a higher or lower PS I/IIratio was due to acceleration or suppression of apparent PSI formation, and (2) it progressed on a similar time scale tothat of the cell proliferation. The apparent rate constant ofthe change in the PS I/II ratio was proportional to that ofcell proliferation, µ, when this was low, but at highvalues of µ the increase in the rate constant of the changein the PS I/II ratio became smaller, causing a deviation fromthe linear relationship. Results indicate that under autotrophicconditions, the photoregulated composition change occurs asa result of thylakoid development, which accompanies cell proliferation. (Received June 23, 1986; Accepted December 5, 1986)     

Entire nucleotide sequence of the pullulanase gene of Klebsiella aerogenes W70.

We determined the entire nucleotide sequence of the Klebsiella aerogenes W70 pullulanase gene (pulA) contained on a 4.2-kilobase-pair fragment of plasmid pPB174. The amino acid composition deduced from an open reading frame of 3,288 base pairs agreed closely with that determined for the intracellular pullalanase. The precursor enzyme consisted of 1,096 amino acid residues and contained a hydrophobic N-terminal signal peptide and the consensus sequence for the bacterial prelipoprotein signal peptide cleavage site.     

Effect of Supra-High Irradiation on the Photosynthetic System of the Cyanophyte Synechocystis PCC 6714

Stability of thylakoid components under supra-high irradiancewas studied with the cyanophyte Synechocystis PCC 6714. Theactivity of overall photosynthesis was quickly inactivated (T_1/2=20min) under supra-high irradiance (300 W m^–2, white light).In parallel with the inactivation of photosynthesis, QA in PSII was also inactivated. Both inactivations were acceleratedby chloramphenicol (CAP) addition. The reactivation of PS IIrequired weak irradiation and was suppressed by CAP. However,PS I measured as P700 was very stable. The level of PS I measuredas P700 was not significantly reduced by the irradiation for12 h even in the presence of CAP while the level of Cyt b₅₅₉,component of PS II, was decreased markedly. The function ofPS I before and after supra-high irradiation with CAP was examinedby comparing sizes of P700 oxidation induced by a short flash,by a continuous light, and by determination of O₂-and ferredoxin-reduction.No difference was observed in PS I actions before and afterthe irradiation treatment. These results indicate that the PSI complex is very tolerant of supra-high irradiation. However,the cells grown under supra-high irradiance contained much fewerPS I and PS II complexes than Cyt b₆–f complexes. Theformer levels were reduced to a half to one fourth of thosebefore growth while the level of Cyt b₆–f complex wasnot reduced so much. A possible mechanism for changes in thylakoidcomposition under supra-high irradiation was discussed. (Received February 16, 1991; Accepted June 12, 1991)     

Vasoactive intestinal peptide stimulates ciliary motility in rabbit tracheal epithelium: modulation by neutral endopeptidase.

We studied the effect of vasoactive intestinal peptide (VIP) on ciliary activity in rabbit cultured tracheal epithelium by a photoelectric method in vitro. Administration of VIP (10(-7) M) elicited an increase in ciliary beat frequency (CBF) from the baseline values of 970 +/- 52 to 1139 +/- 75 beats/min (mean +/- S.E., P less than 0.01). This ciliostimulatory effect was dose-dependent, with the maximal increase and EC50 value being 17.4 +/- 1.0% (P less than 0.05) and 6.10(-11) M, respectively. The VIP-induced increase in CBF was abolished by pretreatment of cells with [4-Cl-D-Phe6, Leu17]-VIP, a VIP receptor antagonist. The neutral endopeptidase inhibitor phosphoramidon (10(-5) M) potentiated the effect of VIP, so that the CBF dose-response curve for VIP was shifted to lower concentrations by 0.5 log U. The administration of VIP increased cyclic AMP levels in epithelial cells, an effect that was also potentiated by phosphoramidon. These results suggest that VIP may interact with its specific receptors and stimulate airway ciliary activity probably through the activation of adenylate cyclase, and that neutral endopeptidase may play a role in modulating this effect of VIP.     

Mutual interactions between optic lobe circadian pacemakers in the cricket Gryllus bimaculatus

The coupling mechanism between the bilaterally paired optic lobe circadian pacemakers in the cricket Gryllus bimaculatus was investigated by recording locomotor activity, under constant light or constant red light, after the optic nerve was unilaterally severed.