Armillaria species in Japan identified by isozyme patterns with special reference to the biological species of the northern hemisphere

Isozyme patterns were examined to characterize biological species ofArmillaria in Japan. Of 25 different enzymes tested, glutamate dehydrogenase (GDH), lactate dehydrogenase (LDH), and aspartate aminotransferase (AAT) showed the most stable and reliable activities. These isozyme patterns showed little variability between haploid and diploid hyphae even under different cultural conditions among isolates tested. From the results, six Japanese biological species were clearly characterized through combination of GDH and LDH isozymes. There were no differences on the whole in isozyme patterns among European biological species ofArmillaria.     

Enzymatic saccharification of spent wood-meal media made of 5 different tree species after cultivation of edible mushroom <Emphasis Type="Italic">Auricularia polytricha</Emphasis>

The chemical characteristics and the suitability for enzymatic saccharification in the spent culture media (SCM) of Auricularia polytricha were examined in order to investigate the utilization of the SCM as a biomass resource for alternative energy production. Wood meals from 3 hardwood species (Quercus serrata, Betula platyphylla var. japonica, and Alnus japonica) and 2 softwood species (Pinus densiflora and Cryptomeria japonica) were used as basal culture media. Dry weight of fruiting bodies were higher in the cultural media made of B. platphylla var. japonica and A. japonica. Amount of weight loss in media showed almost the same value among the cultural media made of 5 species, except for media made of C. japonica. The amounts of the main chemical components (Klason lignin, holocellulose, and α-cellulose) in SCM showed lower values than those in wood meals (WM) and fresh media (FM). After saccharification of the media by Meiselase for 48 h, the hydrolysis weight decrease dramatically increased in SCM. The amount of glucose in SCM ranged from 10.9 to 19.2 g/100 g dry biomass. The highest amount of glucose was obtained in the SCM from B. platyphylla var. japonica. These results indicate that SCM of A. polytricha is a suitable biomass material to produce fermentable sugars for bio-ethanol production.     

Can research on the early marine life stage of juvenile chum salmon <Emphasis Type="Italic">Oncorhynchus keta</Emphasis> forecast returns of adult salmon? A case study from eastern Hokkaido,Japan

To examine the efficacy of juvenile salmon research as a tool for forecasting adult returns, the results from a study on the early marine life stage of juvenile chum salmon, conducted in the Nemuro Strait during 1999–2002 (i.e., 1998–2001 brood years), were compared with the return rates of adult salmon. Among the four brood years, the 2000 brood year (i.e., salmon migrating to the sea in 2001) was previously reported as showing higher abundance, higher growth rate and better somatic condition during the coastal residency period. Consequently, we expected it to have the highest return rate, under a hypothesis that juvenile survival in coastal residency regulates brood-year strength. Contrary to this expectation, the 2000 brood year had almost the lowest return rate. Alternatively, a statistical model in which sea surface temperature during the first year of marine life and size at release were utilized as explanatory variables reconstructed the actual variability in return rates more accurately than that based on the early marine life stage. Possible reasons for the discrepancy between the results of the juvenile salmon research and adult returns are discussed, and we suggest improvements for future research on juvenile salmon.     

Winter longitudinal variation in the body size of larval fishes in the Seto Inland Sea,Japan

This study revealed the spatial variation in abundance and body size of larval fishes in the Seto Inland Sea, Japan, in January 2014 and 2015. Fish larvae were collected by a 1.3-m-diameter ring net towed at the surface and at 10-m depth at 21 stations. The most dominant species was the sandlance Ammodytes japonicus, constituting 82% of total larval fish caught. The body size of A. japonicus was greater [ca. 9 mm total length (TL) in 2014] in eastern areas than in western areas (ca. 5 mm TL in 2014). This trend was also observed in rockfishes (Sebastiscus marmoratus and Sebastes inermis species complex), suggesting a common phenomenon in this region. Because the water temperature was lower in eastern areas, it is likely that the longitudinal differences in larval body size are attributable to earlier spawning in eastern areas caused by different temperature conditions.     

Evaluation of a rapid coliform detection kit from clinical mastitis milk using colloidal gold nanoparticle–based immunochromatographic strips

The accurate identification of mastitis‐causing bacteria assists in effective management by both dairy farmers and veterinarians and can be used to implement the selective use of antimicrobials for treatment. The purpose of this study was to evaluate the ability of our developed anti–ribosomal protein-L7/L12 antibody–coated immunochromatographic strip (ICS) test to detect coliforms in milk by comparing the results with the bacteriological culture method. We investigated the performance of the ICS test as compared with the bacteriological culture method using 308 milk samples from clinical bovine mastitis. First, to determine the optimal ICS test cutoff point for detecting coliform mastitis, we developed a receiver-operating characteristic curve. The result showed that the cutoff point was at 0.5 of our index. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value of the ICS test were 81.3%, 84.8%, 69.2%, and 91.54%, respectively. As the clinical signs increased in severity, the F-measure, a weighted harmonic mean of the sensitivity and overall PPV performance, increased. Because it is especially important to treat clinical mastitis appropriately in the early stages of detection, the ICS test, which can be used by both dairy farmers and veterinarians on dairy farms, is considered to be a useful tool for detecting coliform mastitis, which often presents with severe signs.     

Study on the Mechanism of the Blood-Glucose-Lowering Effect of Collagen Peptides from Sturgeon By-Products

In a previous study, we found that the collagen peptides prepared from the by-products of Bester sturgeon had an inhibitory effect on elevated blood glucose levels in a glucose tolerance test with ICR mice. In the present study, we examine the mechanism of the effect of sturgeon collagen peptides (SCPs) in detail. When glucose was orally administered to mice along with the SCPs, it was found that the glucose remained in the stomach for a longer time. In the above tests, the amount of glucose excreted in the feces of mice also increased. On the contrary, it was revealed that the SCPs have a dipeptidyl-peptidase-IV (DPP-IV) inhibitory ability in an in vitro test. In subsequent oral and intravenous glucose administration tests, glucagon-like peptide-1 (GLP-1) and insulin levels in the blood of mice were maintained at high levels. These results suggested the following three mechanisms: SCPs slow the rate of transportation of glucose from the stomach into the small intestine, resulting in delayed glucose absorption; SCPs suppress the absorption of glucose in the small intestine and excrete it from the body; SCPs inhibit DPP-IV in the blood and maintain a high GLP-1 level in blood, which in turn stimulates insulin secretion.     

A tough, thermally conductive silicon carbide composite with high strength up to 1600 degreesC in Air

A sintered silicon carbide fiber-bonded ceramic, which consists of a highly ordered, close-packed structure of very fine hexagonal columnar fibers with a thin interfacial carbon layer between fibers, was synthesized by hot-pressing plied sheets of an amorphous silicon-aluminum-carbon-oxygen fiber prepared from an organosilicon polymer. The interior of the fiber element was composed of sintered beta-silicon carbide crystal without an obvious second phase at the grain boundary and triple points. This material showed high strength (over 600 megapascals in longitudinal direction), fibrous fracture behavior, excellent high-temperature properties (up to 1600 degreesC in air), and high thermal conductivity (even at temperatures over 1000 degreesC).