Heat shock factor 1 induces a short burst of transcription of the clock gene Per2 during interbout arousal in mammalian hibernation.

During winter hibernation, a diverse range of small mammals can enter prolonged torpor. They spend the nonhibernation season as a homeotherm but the hibernation season as a heterotherm. In the hibernation season, chipmunks (Tamias asiaticus) cycle regularly between 5 and 6 days-long deep torpor with a body temperature (Tb) of 5 to 7 °C and interbout arousal of ∼20 h, during which, their Tb returns to the normothermic level. Here, we investigated Per2 expression in the liver to elucidate the regulation of the peripheral circadian clock in a mammalian hibernator. In the nonhibernation season, as in mice, heat shock factor 1, activated by elevated Tb during the wake period, activated Per2 transcription in the liver, which contributed to synchronizing the peripheral circadian clock to the Tb rhythm. In the hibernation season, we determined that the Per2 mRNA was at low levels during deep torpor, but Per2 transcription was transiently activated by heat shock factor 1, which was activated by elevated Tb during interbout arousal. Nevertheless, we found that the mRNA from the core clock gene Bmal1 exhibited arrhythmic expression during interbout arousal. Since circadian rhythmicity is dependent on negative feedback loops involving the clock genes, these results suggest that the peripheral circadian clock in the liver is nonfunctional in the hibernation season.

Identification of sesquiterpene aldehydes as volatile antifungal compounds in Phaeolepiota aurea culture filtrate.

The culture filtrate extract of golden bootleg (Phaeolepiota aurea) exhibited strong antifungal activity in a bioassay for volatile compounds. Purification of active compounds through silica gel column chromatography and HPLC isolated two compounds, 1 and 2, with molecular weights of 234 and 259, respectively, as confirmed by mass spectrometry. NMR analysis identified these compounds as new sesquiterpenoids with the α-bourbonene skeleton. Both compounds had an aldehyde group, while 2 possessed a cyanohydrin group. These compounds were named phaeolep aldehydes A (1) and B (2). Phaeolep aldehyde A inhibited hyphae elongation of Penicillium citrinum, Aspergillus niger, Cladosporium sphaerospermum, and Alternaria brassicicola at 10 ppm, but did not exhibit any antibacterial activity. In contrast, phaeolep aldehyde B exhibited potent inhibitory effects on the spore germination of Pe. citrinum, achieving 58.2% inhibition at 0.25 ppm, outperforming phaeolep aldehyde A, which exhibited 25.7% inhibition at 10 ppm.

Real-time hybrid angular-interrogation surface plasmon resonance sensor in the near-infrared region for wide dynamic range refractive index sensing.

Herein, we integrated angle-scanning surface plasmon resonance (SPR) and angle-fixed SPR as a hybrid angular-interrogation SPR to enhance the sensing performance. Galvanometer-mirror-based beam angle scanning achieves a 100-Hz acquisition rate of both the angular SPR reflectance spectrum and the angle-fixed SPR reflectance, whereas the use of near-infrared light enhances the refractive index (RI) sensitivity, range, and precision compared with visible light. Simultaneous measurement of the angular SPR reflectance spectrum and angle-fixed SPR reflectance boosts the RI change range, RI resolution, and RI accuracy to 10-1-10-6 RIU, 2.24 × 10-6 RIU, and 5.22 × 10-6 RIU, respectively. The proposed hybrid SPR is a powerful tool for wide-dynamic-range RI sensing with various applications.