Spectroscopic properties and temperature induced electronic configuration changes of all-<Emphasis Type="Italic">trans</Emphasis> and 15-<Emphasis Type="Italic">cis</Emphasis> β-carotenes in ionic liquids

The clear vibrational structure of fluorescence spectrum of β-carotene in the solvent is reported for the first time at room temperature. This finding is in good agreement with recently discovered covalent 3 ¹A _g ⁻ new carotenoid state. The fluorescence yield of β-carotene in ionic liquid (1-methyl-3-octyloxymethylimidazolium tetrafluoroborate) is around hundred times higher than in standard solvent n-hexane. The all-trans and 15-cis β-carotene fluorescence yields in ionic liquid are 1.96±0.03 and 2.53±0.03 %, respectively. The ionic liquid is a very useful tool for modelling photosynthetic system in situ. We present the electronic absorption data of β-carotene in ionic liquids (so called neoteric solvents) with special interest in the absorption changes as a function of temperature in the range 0–90 °C (273–363 K). Ionic liquids are also very good medium for temperature study, because they are not changing up to several hundred °C and also not evaporating during heating. The relationship between spectral characteristics of β-carotene in new generation solvents with increasing and decreasing temperature is evaluated. The energy value of the ionic state 1 ¹B _u ⁺ of synthetic β-carotene in ionic liquids exhibits a linear and temperature reversible dependence on temperature up to 30 °C (303 K) and up to 40 °C (313 K) for 15-cis and all-trans β-carotenes, respectively. This is valid for both 0-0 and 0-1 transitions.     

Bimodal clock gene expression in mouse suprachiasmatic nucleus and peripheral tissues under a 7-hour light and 5-hour dark schedule

Using the mPer1::luc real-time monitoring technique, the authors observed the bimodal patterns of mPer1 bioluminescence on each side of the SCN, in parallel with maintaining synchronization between the left and right sides of the SCN under an artificial light:dark:light:dark (LDLD) 7:5:7:5 condition. In situ hybridization analysis of mPer1 and mBmal1 mRNA distribution in the SCN showed that in 1 photophase (morning photophase; M) of LDLD, the mPer1 level in the ventrolateral-like (VL-like) subdivision of the SCN was higher than that in the dorsomedial-like (DM-like) subdivision, and this regional distribution pattern was reversed in another photophase (evening photophase; E). In contrast, the mBmal1 level was higher in the DM-like subdivision than in the VL-like subdivision in the M phase, and this distribution changed in the E phase. The prokineticin 2 (PK2) mRNA that encodes an SCN output molecule that is thought to transmit the circadian locomotor rhythms was reduced in both the DM-like and VL-like SCN and did not clearly correlate with the activity under the LDLD condition. The expression of mPer1 and mPer2 in the liver was clearly bimodal, whereas the expressions of other clock genes were not synchronized to the LDLD condition. These results may provide important insights into the mechanism underlying the splitting or bimodal rhythms that may in turn facilitate the understanding of the ability to measure the seasonal day length in mammals.     

In vitro analysis of His-Asp phosphorelays in Aspergillus nidulans: the first direct biochemical evidence for the existence of His-Asp phosphotransfer systems in filamentous fungi

His-Asp phosphorelays are widespread signal transduction mechanisms in bacteria, fungi, and higher plants. In order to investigate a His-Asp phosphorelay network in filamentous fungi, which has been genetically characterized in part, we attempted to construct an in vitro phosphotransfer network in Aspergillus nidulans comprising all the necessary components. As a first step, we established an in vitro phosphotransfer system with a histidine-containing phosphotransmitter YpdA, a response regulator SrrA, and a bacterial histidine kinase ArcB as a phosphate donor. We demonstrated the phosphotransfer from ArcB to A. nidulans YpdA and the subsequent transfer from YpdA to SrrA. This is the first direct biochemical evidence for the presence of the phosphotransfer system in filamentous fungi. Furthermore, a retrograde phosphorylation from YpdA to FphA, a histidine kinase similar to bacterial phytochrome, was found. The overall picture of the His-Asp phosphorelays in A. nidulans is discussed based on the results of the in vitro study.     

Anti-influenza virus activity of biflavonoids

Ginkgetin was found to inhibit the influenza virus sialidase. Ginkgetin-sialic acid conjugates showed a significant survival effect in the influenza-virus-infected mice.     

Novel linear polymers bearing thiosialosides as pendant-type epitopes for influenza neuraminidase inhibitors

A conventional synthesis of alpha-thioglycoside of sialic acid as a glycomonomer was accomplished. Radical copolymerization of the glycomonomer with vinyl acetate proceeded smoothly to afford a new class of glycopolymers having thiosialoside residues, in which all protection was removed by a combination of transesterification and saponification to provide a water-soluble thiosialoside cluster. The results of a preliminary study on biological responses against influenza virus neuraminidases using the thiosialoside polymer as a candidate for a neuraminidase inhibitor showed that the glycopolymer has potent inhibitory activity against the neuraminidases.     

Synthesis of fluorescent and photoaffinity-labeled derivatives of bisphenol A and their inhibitory activity toward hypoxic expression of erythropoietin

Bisphenol A derivatives, possessing a fluorescent dye and a photo-reactive group, were synthesized from bisphenol A, and the inhibitory activity of the derivatives was evaluated against hypoxic response. The synthesized derivatives were found to inhibit the hypoxic expression of erythropoietin in Hep3B cells as well as bisphenol A.