Growth and maturation in sterlet <Emphasis Type="Italic">Acipenser ruthenus</Emphasis> under high concentrations of dissolved oxygen

This study investigates the effect of high dissolved oxygen concentrations (DO) on sterlet Acipenser ruthenus maturation. Two groups, each comprising 246 individuals of 8-month-old juvenile sterlets, were reared for 37 months under high DO (group H, mean DO of 11.2 mg/L) or normal DO (group C, mean DO of 7.3 mg/L). Significant differences in body weight were observed between group H (638.7?±?191.9 g) and group C (572.2?±?151.9 g) in 12 months (P?<?0.05). Growth until 12 months occurred at a specific growth rate of 0.6%/day for group H and at 0.5%/day for group C. The food conversion rate of groups H and C was 5.2 and 5.8, respectively. The gonadosomatic index of group H was 3.1?±?1.1 for females and 3.1?±?9.7 for males, and showed no significant difference with group C (3.0?±?0.7 for females and 2.8?±?8.9 for males, P?>?0.05) in 24 months. Significant differences in follicle diameter in mature females were also observed. Group H included 68 mature females, with an average follicle diameter of 2318.0?±?175.3 µm, whereas group C included 56 mature females, with a smaller average follicle diameter of 2152.3?±?287.0 µm (P?<?0.001). However, the polarization index in group H (0.194?±?0.049) was higher than that in group C (0.178?±?0.042) (P?<?0.05). These results suggest that, for sterlet, rearing conditions with high DO can affect growth of both the body and follicle diameter of fish compared to normal rearing conditions.     

Effect of nitrate fertilization of gametophytes of the kelp Undaria pinnatifida on growth and maturation of the sporophytes cultivated in Matsushima Bay, northern Honshu, Japan

In northern Japan, the early production of high-quality specimens of kelps Undaria pinnatifida prior to the outbreak of pinhole disease is needed. To address this need, we tested the effect of nitrate fertilization of gametophytes on the growth and maturation of sporophytes using experimental and control gametophytes derived from sporophytes cultivated in Matsushima Bay, northern Honshu, Japan. From mid-August to October 2008, experimental gametophytes were cultured on a rope indoors at a nitrate concentration of 1 mg/L at the optimal seawater temperature of 20 °C, whereas control gametophytes were cultured without the addition of nitrate in normal seawater at an average temperature of 23.5 °C during this period in the past 30 years. Next, the seedlings were cultivated in Matsushima Bay until March 2009. For the experimental kelps, the total length, stipe length, stipe width, sporophyll length, sporophyll width, and dry weight of the blade, midrib, and sporophyll increased significantly from December to January compared to those of control kelps. Matured sporophylls of the experimental kelps were more than those of the control kelps from early December to late January. Significant higher photosynthesis occurred at seawater temperatures of 10 and 15 °C, as well as higher uptake rates of NO₃–N of the experimental kelps in December and January. These results show that nitrate fertilization of the gametophytes makes it possible to harvest the high-priced blade, midrib, and sporophyll in January, which is earlier than the traditional harvest date.     

Optimization of a protocol for cryopreservation of mouse spermatozoa using cryotubes

The rapid increase in the number of genetically modified mouse strains has produced a high demand for their frozen spermatozoa from laboratories and mouse banking facilities. Historically, plastic straws have been used preferentially as containers for frozen mammalian spermatozoa because spermatozoa frozen in plastic straws have a high survival rate after thawing. However, plastic straws are more fragile and are used less often than the cryotubes used for conventional cell freezing. In this study, we sought to develop a new protocol for sperm freezing using cryotubes as the container to increase the accessibility of mouse sperm cryopreservation. Epididymal spermatozoa were collected from mature ICR or C57BL/6J (B6) males and were suspended in 18% raffinose and 3% skim milk solution. We then optimized the following conditions using the sperm survival rate as an index: 1) distance of cryotubes from the surface of the liquid nitrogen at freezing, 2) volume of the sperm suspension in the cryotube and 3) temperature of warming sperm during thawing. The best result was obtained when cryotubes containing 10 μl of sperm suspension were immersed 1 cm below the surface of the liquid nitrogen and then thawed at 50 C. The fertilization rates using spermatozoa frozen and thawed using this method were 63.1% in ICR mice and 28.2% in B6 mice. The latter rate was increased to 62.3% by adding reduced glutathione to the fertilization medium. After embryo transfer, 68% and 62% of the fertilized oocytes developed into normal offspring in the ICR and B6 strains, respectively. These results show that cryotubes can be used for cryopreservation of mouse spermatozoa under optimized conditions. This protocol is easy and reproducible, and it may be used in laboratories that do not specialize in sperm cryopreservation.     

Software development for estimating the concentration of radioactive cesium in the skeletal muscles of cattle from blood samples

The 2011 earthquake severely damaged the Fukushima Daiichi Nuclear Power Plant (FNPP), resulting in the release of large quantities of radioactive material into the environment. The deposition of these radionuclides in rice straw as livestock feed led to the circulation of contaminated beef in the market. Based on the safety concern of the consumers, a reliable method for estimating concentrations of radioactive cesium in muscle tissue is needed. In this study, we analyzed the concentrations of radioactive cesium in the blood and skeletal muscle of 88 cattle, and detected a linear correlation between them. We then developed software that can be used to estimate radioactive cesium concentrations in muscle tissue from blood samples. Distribution of this software to the livestock production field would allow us to easily identify high‐risk cattle, which would be beyond the safety regulation, before shipping out to the market. This software is planned to be released as freeware. This software would contribute to food safety, and aid the recovery of the livestock industry from the damage creacted by the 2011 Tohoku earthquake and tsunami.     

Effects of chitin and chitosan on collagen synthesis in wound healing

Collagen synthesis was evaluated by measuring prolyl hydroxylase (PHL) activity induced within rat granulation tissue by a polyester non-woven fabric (NWF, 1 x 1 cm, 0.6 mm in thickness) impregnated with a chitin or chitosan suspension ranging in concentration from 0.1 to 10 mg/ml. In addition, PHL activity induced in rat granulation tissue by a NWF impregnated with a phosphate buffer solution was examined as a control. The PHL activity in each group remained low until 4 days post-implantation (Day 4). However, in the 10 mg chitin group, the PHL activity increased rapidly without scatter of the data at Day 7 and remained at a plateau until Day 14. In other groups, PHL activity increased linearly until Day 14. The data varied widely at Day 7. Compared to chitosan, chitin at the higher concentration was found to induce stable collagen synthesis in the early wound healing process.     

Relations between various extracted basic densities and wood chemical components in Eucalyptus globulus

Relations between various extracted basic densities and wood chemical components were investigated by their within-tree variations in Eucalyptus globulus for assistance in the prediction of the properties of wood or wood-derived products. Extraneous compounds affect the relations between various basic densities and wood chemical components such as holocellulose and the lignin syringyl/guaiacyl ratio. We also discuss the relation of various densities, the molar composition of neutral sugars constituting hemicellulose, and fiber morphology.     

Xenotransplantation of porcine pancreatic endocrine cells to total pancreatectomized dogs

Xenotransplantation of porcine pancreatic endocrine (PE) cells in a diffusion chamber, a bioartificial endocrine pancreas (Bio-AEP), was conducted to total pancreatectomized dogs. Six pancreatectomized dogs were divided into two groups of 3 dogs each. In three dogs of the control group, exogenous insulin was administered twice a day for 30 weeks to maintain fasting blood glucose (FBG) levels within the normal range. The remaining three dogs were implanted with Bio-AEPs (implantation group), in addition to daily insulin administration. In the implantation group, Bio-AEPs containing 1.3 to 1.8 x 10(7) cells per kg of body weight of the recipient were implanted without fixation into the abdominal cavity. In the control group, exogenous insulin requirements did not decrease during the experimental period, whereas it significantly decreased for a certain period (3, 11, 17 weeks) after implantation in all implanted dogs. In the implantation group, laparotomy was performed after FBG and the exogenous insulin requirement increased again and Bio-AEPs were removed. Two Bio-AEPs were completely destroyed, and the remaining one was encapsulated by thin fibrous tissue. In this dog, effusion was present within the capsule, but the Bio-AEP was not destroyed. Histopathologically, the necrosis, presumably caused by hypoxia, of the PE-cells was observed on transmission electron microscopy. In conclusion, Bio-AEP could function for a certain period after implantation in this study. However, more preclinical researches should be needed to apply this technique for the treatment of diabetic dogs.     

Application of laser-assisted zona drilling to in vitro fertilization of cryopreserved mouse oocytes with spermatozoa from a subfertile transgenic mouse

Development of assisted reproductive technologies is necessary to obtain fertilized oocytes in a subfertile transgenic mouse strain. Here, we showed the application of laser-assisted drilling of the zona pellucida to in vitro fertilization of cryopreserved mouse oocytes with sperm from subfertile transgenic mice (C57BL/6N-Tg(UCP/FAD2)U8 strain). After cryopreservation by vitrification, the recovery and survival rates of the zona-drilled mouse oocytes were 97% (97/100) and 94% (91/97), respectively. In vitro fertilization of the cryopreserved zona-drilled mouse oocytes with sperm from the subfertile transgenic mice was greatly facilitated (60%, 55/91) compared to that of the cryopreserved zona-intact mouse oocytes (11%, 81/768). In vitro fertilized embryos that developed to the 2-cell stage were again cryopreserved by vitrification, and after warming they were transferred into recipient females. Subsequently, six viable offspring were delivered, and all were confirmed to be transgenic mice. These results indicate that laser-assisted zona drilling of oocytes combined with cryopreservation by vitrification may be a useful approach for large-scale production of in vitro fertilized embryos for managing transgenic mouse strains with reproductive disabilities such as subfertile sperm.