RESUMO
The authors evaluated the adaptability of male nine-spined sticklebacks (Pungitius sinensis) at three salinity levels (0, 5 and 10 psu) by comparing nest building success rates with nest structures. Successful nest building decreased as salinity increased. In addition, nests built in fresh water (i.e., 0 psu) were glued together, whereas those built in brackish water (5 and 10 psu) broke easily and fell from the nest site to the gravel bottom. Based on these findings, the authors suggest that P. sinensis adapts to freshwater environments.
Assuntos
Smegmamorpha , Masculino , Animais , Salinidade , Água Doce , Adaptação FisiológicaRESUMO
The atomic and electronic dynamics in the topological insulator (TI) Bi2Te3 under strong photoexcitation were characterized with time-resolved electron diffraction and time-resolved mid-infrared spectroscopy. Three-dimensional TIs characterized as bulk insulators with an electronic conduction surface band have shown a variety of exotic responses in terms of electronic transport when observed under conditions of applied pressure, magnetic field, or circularly polarized light. However, the atomic motions and their correlation between electronic systems in TIs under strong photoexcitation have not been explored. The artificial and transient modification of the electronic structures in TIs via photoinduced atomic motions represents a novel mechanism for providing a comparable level of bandgap control. The results of time-domain crystallography indicate that photoexcitation induces two-step atomic motions: first bismuth and then tellurium center-symmetric displacements. These atomic motions in Bi2Te3 trigger 10% bulk bandgap narrowing, which is consistent with the time-resolved mid-infrared spectroscopy results.
RESUMO
Changes in mRNA levels of prolactin (PRL) during seaward migration and after experimental transfer from fresh water (FW) to seawater (SW) were examined in larvae of the amphidromous fish, ayu Plecoglossus altivelis. In the field study, ayu larvae caught in the surf zone showed lower levels of PRL mRNA than those in the river, while growth hormone (GH) levels showed no significant change. Decrease in PRL gene transcription was also observed 24h after direct transfer from FW to SW, whereas there was no significant influence of water temperature. On the other hand, there was no significant change in GH mRNA levels in relation to SW transfer or environmental temperature. In a raceway with a vertical salinity gradient, PRL mRNA levels of ayu larvae showed a significant reduction during spontaneous migration from FW to SW, which mimicked the results from the field observation and the transfer experiment, and then a gradual increase during the course of development. Whole body water and sodium contents of larvae in a salinity gradient were stable during migration to SW. Results in this study indicated the importance of regulation of PRL gene expression in the downstream migration and acclimation to SW during the early development of ayu.
