Dormancy Characteristics of Malus ‘Snowdrift’ and Effects of Spraying 6-benzyladenine on Its Germination and Flowering in Long-day Treatment

[Objective] The dormancy characteristics of Malus ‘Snowdrift’ in long-day treatment were studied, and 6-BA was used to break the dormancy, with the aim to achieve the purpose of flowering in autumn. [Method] The new shoots of ‘Snowdrift’ in long-day treatment were conducted with hydroponics to investigate their dormancy time. And cytokinin 6-benzyladenine(6-BA)was used to treat the dormant shoots, to investigate the budding, flowering and flower bud differentiation. [Result] The shoots in long-day treatment entered endodormancy after August 7~(th) and the shoots in the natural daylight entered endodormancy before July 18~(th). In long-day treatment, 116 buds, 198 flowers were observed after 6-BA spraying. [Conclusion] The optimum concentration of 6-BA was 300 mg/L. And the flower bud differentiation of ‘Snowdrift’ in long-day treatment was faster than those in natural daylight after 6-BA spraying.     

Effect of simulated acid fog on membrane-bound calcium (mCa) in fir (Abies firma) and cedar (Cryptomeria japonica) mesophyll cells

The decline of virgin fir (Abies firma) forest at Mt. Oyama has been reported. Related field observations suggest that high acidity fog is linked with its decline. However, cedar (Cryptomeria japonica) in the same area shows no symptoms of decline. For assessing effects of acid fog on membrane-bound calcium (mCa) of the leaf mesophyll cells, 9-year-old seedlings of fir (Abies firma) and 8-year-old seedlings of cedar (Cryptomeria japonica) were exposed twice a week to simulated acid fog (SAF at pH 3 with pH 5 as control) for 2 h per day in a chamber during May–December 2007 (except August). Current and 1-year-old needles were collected from seedlings and analyzed at 1-month intervals. For current-year needles of fir, mCa levels in cells exposed to SAF at pH 3 were significantly lower than in cells exposed to pH 5, especially during September 2007–March 2008. In contrast, it is noteworthy that mCa levels of cedar were maintained as virtually constant irrespective of SAF acidity, indicating that fir is more sensitive to acid fog than is cedar. Based on these results, mCa loss by acid fog might also be caused in the declining virgin fir forest at Mt. Oyama.     

Protein Requirements of the Freshwater Prawn Macrobrachium rosenbergii Evaluated by the Factorial Method

The dietary protein requirement of the freshwater prawn Macrobrachium rosenbergii to obtain the maximum body protein retention was assessed by the estimated protein needed daily for maintenance (M) and body protein increment (G). The body protein increment was estimated by quantifying body nitrogen increments when the prawn was fed high‐protein diets composed primarily of casein. The protein required for maintenance was estimated by regressing weight gains in feeding experiments using graded dietary levels of casein. The true daily retention (R) or increase in body protein of the prawn corresponds to the sum of M and G. The values of M, G, and R determined in the present study were 3.86, 0.24, and 4.10 g/kg body weight/d, respectively. On the basis of the daily body protein increment and the net protein utilization of casein (58%), dietary protein requirement of the juvenile M. rosenbergii for maximum body protein retention was suggested to be about 7.1 g/kg body weight/d.     

Cytotoxicity for porcine islet cells by complement of six animal species

Complement-mediated cytotoxicity for porcine islet cells (PICs) was evaluated using sera of six animal species. Then soluble complement receptor type-1 (sCR1) as an anti-complement agent was added to those sera, and the changes in 50% hemolytic unit of complement serum (CH50) and cytotoxic effect of those sera on PICs were examined. All the sera except for that of pig showed cytotoxicity. However, the extent of toxicity was considerably different between species. In the rat and human serum, sCR1 significantly reduced CH50 and cytotoxicity, however in the dog serum, sCR1 had no suppressive effects. These results may suggest that complement contribute to humoral cytotoxicity for PICs as a main factor, and the compatibility of complement with PICs differs between animal species.     

Effects of Brief Summer or Winter Fasting on the Muscle Quality of Cultured Pacific Bluefin Tuna (Thunnus orientalis)

The effects of fasting on the quality of the dorsal and ventral ordinary muscles from cultured Pacific bluefin tuna (Thunnus orientalis) during chilled storage were investigated. Tuna were subjected to fasting for 2 days in the summer or 6 days in the winter prior to harvesting. The breaking strength of the dorsal ordinary muscle sampled in the summer increased until 24 h and then decreased. There were no significant differences in the lipid and glycogen content of the ordinary muscle after 9 h of storage between the controls and either fasting group. The pH of the ordinary muscle subjected to summer and winter fasting was higher than in the controls after 24–48 h of storage. However, the relationship between the pH and glycogen content was unclear. The metmyoglobin content during chilled storage was lower in the ordinary muscles from either fasting group than in the controls. In conclusion, fasting for 6 days in the winter improved the color stability of the ordinary muscle without a decline in its lipid content.     

Identification of a resistant protein from scallop shell extract and its bile acid-binding activity

In this study, we showed that feeding rats the organic extract of scallop shells (scallop shell extract) caused a decrease in the weights of white adipose tissues in rats fed a high-fat diet. In addition, the cholesterol concentration in the serum of rats that received a diet containing scallop shell extract was significantly lower than that in the serum of rats on the control diet. Feeding this scallop shell extract to rats increased the fecal weight as well as the fecal excretion of bile acids. The amino acid composition of the feces from rats fed the scallop shell extract was different from that of feces from rats fed the control diet, and treatment of the extract with pepsin and pancreatin identified a protein with a molecular weight of 90 kDa (90-kDa protein) as one of the indigestible proteins. Interestingly the 90-kDa protein was found to be identical to a free radical-scavenging protein we previously identified and showed the ability to bind bile acids. These results suggest that indigestible proteins (resistant proteins) in the scallop shell extract, including the 90-kDa protein, inhibit the absorption of bile acid by binding to it and cause increased excretion of fecal bile acid, which subsequently may decrease the serum cholesterol level.     

Can fermented soybean meal and squid by‐product blend be used as fishmeal replacements for Japanese flounder (Paralichthys olivaceus)?

An experiment was carried out to evaluate fermented soybean meal and squid by‐product blend (1:1) (FP) as replacement of fishmeal (FM) for Japanese flounder, Paralichthys olivaceus. Five isocaloric (19 kJ g^?1) diets were prepared by replacing 0 (FP0), 12 (FP12), 24 (FP24), 36 (FP36) and 48% (FP48) FM protein with FP. Triplicate groups of juveniles (mean weight of 3.9 g) were delivered the test diets for 8 weeks in a flow‐through sea water system. The results showed that there were no significant differences (P > 0.05) among the growth rates of fish fed FP0, FP12, FP24 and FP36 diets. Growth and nutrient utilization parameters were significantly reduced in fish fed FP48 diet. Although, whole body proximate composition of fish were not significantly affected by the dietary treatments compared to the control; methionine and phenylalanine contents were significantly decreased in FP48 group. Protein retention was also significantly decreased in the similar group of fish. Dietary treatments did not alter most of the plasma metabolites, while some of the health parameters were improved in the replacement groups. Results suggested that FP is a potential candidate for alternative protein ingredient in aquafeed and can replace 36% FM protein in the diet of Japanese flounder.     

Prevalence of equine herpesvirus type 1 strains of neuropathogenic genotype in a major breeding area of Japan

A single non-synonymous nucleotide substitution of guanine (G) for adenine (A) at position 2254 in the viral DNA polymerase gene (encoded by open reading frame [ORF] 30) of equine herpesvirus type 1 (EHV-1) has been significantly associated with neuropathogenic potential in strains of this virus. To estimate the prevalence of EHV-1 strains with the neuropathogenic genotype (ORF30 G(2254)) in the Hidaka district--a major horse breeding area in Japan--we analyzed the ORF30 genomic region in cases of EHV-1 infection in this area during the years 2001-2010. Of the 113 cases analyzed, 3 (2.7%) were induced by ORF30 G(2254) strains. This prevalence is lower than those observed in the U.S.A. (10.8-19.4%), Argentina (7.4%), France (24%), and Germany (10.6%).