Water‐immersion restraint stress disrupts nonenzymatic antioxidant defense systems through rapid and continuous ascorbic acid depletion in the adrenal gland of rats

We examined whether water‐immersion restraint stress (WIRS) disrupts nonenzymatic antioxidant defense systems through ascorbic acid depletion in the adrenal gland of rats. Rats were exposed to WIRS for 0.5, 1.5, 3 or 6 h. WIRS increased serum adrenocorticotropic hormone, corticosterone and glucose concentrations and adrenal corticosterone content at each time point. WIRS increased adrenal lipid peroxide content at 3 and 6 h, and the increase was twofold higher than the unstressed level at 6 h. WIRS decreased adrenal ascorbic acid content at each time point, and the decrease reached one‐third of the unstressed level at 6 h. WIRS increased adrenal reduced glutathione content at 0.5 and 6 h but reduced that content to half of the unstressed level at 6 h. WIRS increased adrenal α‐tocopherol content at 1.5 h but returned that content to the unstressed level thereafter. When rats with 6 h of WIRS was orally preadministered with l ‐ascorbic acid (250 mg/kg), WIRS‐induced changes in adrenal lipid peroxide, ascorbic acid and reduced glutathione contents were attenuated without any change in stress response. These results indicate that WIRS disrupts nonenzymatic antioxidant defense systems through rapid and continuous ascorbic acid depletion in the adrenal gland of rats. Copyright © 2012 John Wiley & Sons, Ltd.     

Autoimmune recognition of thyroglobulin and thyroid hormones in rabbits

Two rabbits (RG-1, RG-2) were immunized with rabbit thyroglobulin (RTg) purified from thyroid glands of four other normal rabbits of the same strain, and bled serially. Antisera were obtained at different times after the first immunization and kept separately and studied. Production of anti-RTg as well as anti-thyroid hormone antibodies such as anti-thyroxine (T4) and anti-triiodothyronine (T3) antibodies was observed in both rabbits. Physicochemical parameters of anti-RTg antibodies with RTg, T4, and T3 were calculated in two selected antisera (70-day and 253-day) of each of the rabbits, using a Scatchard plot. Extraction of serial sera from both rabbits disclosed the presence of larger amounts of T3 and T4 in immune sera than in preimmune serum. Examination of pathology of thyroid glands and kidneys in both rabbits was negative for the lesions of autoimmune thyroiditis and immune nephritis. These results indicate that anti-Tg as well as anti-thyroid hormone autoantibodies can be raised without thyroid pathology in rabbit by immunization with autologous Tg.     

Potential effects of underwater noise from wind turbines on the marbled rockfish (Sebasticus marmoratus)

Environmental assessments of underwater noise on marine species must be based on species-specific hearing abilities. This study was to assess the potential impact of underwater noise from the East China Sea Bridge wind farm on the acoustic communication of the marbled rockfish. Here, the 1/3 octave frequency band of underwater noise was 125 Hz with the level range of 78–96 dB re 1 μPa, recorded at distances between 15-20m from the foundation at wind speed of 3–5 m/s. Auditory evoked potential (AEP) and passive acoustic techniques were used to determine the hearing abilities and sound production of the fish. The resultes showed the lowest auditory threshold of Sebastiscus marmoratus was 70 dB at 150 Hz matching the disturbance sound ranging 140–180 Hz, which indicating the acoustic communication used in this species. However, the frequency and level of turbine underwater noise overlapped the auditory sensitivity and vocalization of Sebastiscus marmoratus. The wind turbine noise could be detected by fish and may have a masking effect on their acoustic communication. This result can be applied for further to the assessent of fish species released into offshore wind farm marine ranch.     

Condition factor dependency of burst swimming ability between wild and hatchery-reared chum salmon fry (Oncorhynchus keta)

Ichthyological Research - Burst swimming velocity (Uburst) was compared between wild and hatchery-reared chum salmon fry. In the hatchery-reared fry, Uburst was significantly correlated with the...     

Light-sheet microscopy-based 3D single-cell tracking reveals a correlation between cell cycle and the start of endoderm cell internalization in early zebrafish development

Controlling the initiation of cell migration plays a fundamental role in shaping the tissue during embryonic development. During gastrulation in zebrafish, some mesendoderm cells migrate inward to form the endoderm as the innermost germ layer along the yolk syncytial layer. However, how the initiation of inward migration is regulated is poorly understood. In this study, we performed light-sheet microscopy-based 3D single-cell tracking consisting of (a) whole-embryo time-lapse imaging with light-sheet microscopy and (b) three-dimensional single cell tracking in the zebrafish gastrula in which cells are marked with histone H2A-mCherry (nuclei) and the sox17:EGFP transgene (expressed in endoderm cells). We analyzed the correlation between the timing of cell internalization and cell division. Most cells that differentiated into endoderm cells began to internalize during the first half of the cell cycle, where the length of a cell cycle was defined by the period between two successive cell divisions. By contrast, the timing of other internalized cells was not correlated with a certain phase of the cell cycle. These results suggest the possibility that cell differentiation is associated with the relationship between cell cycle progression and the start of internalization. Moreover, the 3D single-cell tracking approach is useful for further investigating how cell migration is integrated with cell proliferation to shape tissues in zebrafish embryos.