Changes in volatile compounds of living Pacific oyster Crassostrea gigas during air-exposed storage

Fisheries Science - The changes in volatile compounds of living oysters Crassostrea gigas with shells under air-exposed storage for 7 days at 5 and 20 °C were investigated...     

Time course of the incidence/multiplicity and histopathological features of murine colonic dysplasia,adenoma and adenocarcinoma induced by benzo[a]pyrene and dextran sulfate sodium

Benzo[a]pyrene (BP) is mutagenic but noncarcinogenic in the murine colon. Recently, we reported rapid induction of colonic tumors by treatment of CD2F₁ mice with BP (125 mg/kg for 5 days) followed by a colitis inducer, dextran sulfate sodium (DSS) (4% in drinking water for 1 or 2 weeks). However, there are no reports on detailed time course and histopathological features of colonic proliferative lesions in this model. Here, we show the detailed time course of colonic dysplasia, adenoma and adenocarcinoma induced by treatment with BP, DSS, and a combination of the two (BP/DSS). In the colon of mice exposed to BP/DSS, 14.6 dysplastic foci per mouse were present one week after DSS treatment (week 4). The number of dysplastic foci decreased with time to 3.1 at week 9 and thereafter remained almost constant. At week 4, 1.5 adenocarcinomas were also observed, with a marked increase in numbers with time, reaching 29.3 at week 14. In contrast, the number of dysplastic foci induced by DSS alone showed a time course similar to that following BP/DSS treatment; however, only a few tumors appeared. Neither dysplastic foci nor neoplastic lesions were induced by BP only. In mice exposed to BP/DSS, β-catenin was demonstrated immunohistochemically in the nucleus and/or cytoplasm of the tumor cells, and this translocation from the cell membrane was evident in subsets of dysplastic foci. In dysplastic foci induced by DSS alone, β-catenin was absent in the nucleus/cytoplasm. These finding suggest that aberrant β-catenin accumulation in dysplastic foci is associated with tumor progression in this BP/DSS model.     

Effects of utilization of local food by‐products as total mixed ration silage materials on fermentation quality and intake,digestibility, rumen condition and nitrogen availability in sheep

Four wethers were used in a 4 × 4 Latin square design experiment to evaluate in vivo digestibility of total mixed ration (TMR) silage with food by‐products for dairy cows, and the ruminal condition and nitrogen (N) balance were examined. Five by‐products (i.e. potato waste, noodle waste, soybean curd residue, soy sauce cake and green tea waste) were obtained. Four types of TMR silage were used: control (C) containing roughage and commercial concentrate, T1:20% and T1:40% containing the five by‐products replacing 20% and 40% of the commercial concentrate on a dry matter (DM) basis, respectively, and T2:40% containing three by‐products (potato waste, noodle waste and soybean curd residue) replacing 40% of the commercial concentrate on a DM basis. The ingredients were mixed and preserved in oil drum silos for 4 months. The TMR silages showed 4.02–4.44% and 1.75–2.19% for pH and lactic acid contents, respectively. The digestibility of DM and neutral detergent fiber, and total digestible nutrient content were higher (P < 0.05) for T2:40% feeding than for C feeding. Urinary nitrogen excretion tended to be lower (P = 0.07) for T2:40% than for C. The results suggested 40% replacing of commercial concentrate by using the three food by‐products can be most suitable for TMR silage.     

Mixing‐Recording Method for the Practical Determination of Physical Properties of Soy Protein Isolate

The mixing properties of soy protein isolate (SPI) were investigated. The electric current of a kitchen food processor was monitored during the mixing of SPIs to produce dough, and an identical mixing curve was obtained for each SPI. The obtained peak time and peak height of the electric current curve were correlated to the physical properties (solubility and gel strength) of each SPI. The peak time negatively correlated with solubility, and the peak height positively correlated with gel strength. Optical microscopic observations showed that the dough microstructure appeared to be related to the peak time. Moreover, some conditions such as the SPI storage conditions and the ionic strength of the mixing buffer affected the mixing properties. This mixing‐recording method is proposed as a practical tool that could simplify the evaluation of SPI characteristics.     

Factors influencing red expression in autumn foliage of sugar maple trees

We evaluated factors influencing the development of autumn red coloration in leaves of sugar maple (Acer saccharum Marsh.) by measuring mineral nutrient and carbohydrate concentrations, water content, and phenology of color development of leaves from 16 mature open-grown trees on 12 dates from June through October 1999. Mean foliar nutrient and carbohydrate concentrations and water content were generally within the range published for healthy sugar maple trees. However, foliar nitrogen (N) concentrations were near deficiency values for some trees. The timing and extent of red leaf coloration was consistently correlated with both foliar N concentrations and starch or sugar concentrations, which also varied with N status. Leaves of trees with low foliar N concentrations turned red earlier and more completely than those of trees with high foliar N concentrations. Low-N trees also had higher foliar starch concentrations than high-N trees. During the autumn development of red leaf coloration, foliar starch, glucose and fructose concentrations were positively correlated with red leaf color expression. At peak red expression, the concentrations of glucose, fructose, sucrose and stachyose were all positively correlated with red color expressed as a percent of total leaf area.     

Acid mist and soil Ca and Al alter the mineral nutrition and physiology of red spruce

We examined the effects and potential interactions of acid mist and soil solution Ca and Al treatments on foliar cation concentrations, membrane-associated Ca (mCa), ion leaching, growth, carbon exchange, and cold tolerance of red spruce (Picea rubens Sarg.) saplings. Soil solution Ca additions increased foliar Ca and Zn concentrations, and increased rates of respiration early in the growing season (July). Soil Al treatment had a broad impact, reducing foliar concentrations of Ca, Mg, Mn, P and Zn, and resulting in smaller stem diameters, sapling heights and shoot lengths compared with soil treatments with no added Al. Aluminum treatment also reduced respiration when shoots were elongating in July and decreased net photosynthesis at the end of the growing season (September). Three lines of evidence suggest that Al-induced alterations in growth and physiology were independent of foliar Ca status: (1) Ca concentrations in foliage of Al-treated saplings were within the range of sufficiency established for red spruce; (2) mCa concentrations were unaffected by Al treatment; and (3) no Al x Ca interactions were detected. Acid mist treatment increased foliar Fe and K concentrations and increased leaching of Ca, Mg, Mn, Zn, Fe, and Al from foliage. Leaching losses of Ca were more than twice those of the element with the next highest amount of leaching (Zn), and probably led to the reductions in mCa concentration and membrane stability of acid-treated saplings. Acidic mist resulted in enhanced shoot growth, and consistent reductions in foliar cold tolerance in the fall and winter. Of the few significant interactions among treatments, most involved the influence of mist pH and Al treatment on foliar nutrition. In general, reductions in cation concentration associated with Al addition were greater for pH 5.0-treated saplings than for pH 3.0-treated saplings. We propose that H(+)-induced leaching of mCa from mesophyll cells is the mechanism underlying acid-induced reductions in foliar cold tolerance of red spruce.     

Differences in spectral trajectory with stand volume development between Japanese larch and Japanese oak in Hokkaido,Japan

Our objective was to investigate the differences in the spectral trajectory of the LANDSAT Thematic Mapper with stand volume development between Japanese larch (Larix kaempferi) and Japanese oak (Quercus mongolica var. crispula) in the experimental forest of Kyushu University, Hokkaido, Japan. We used nonlinear regression and a categorical variable to investigate the relationship between spectral reflectance factor and stand volume for each forest type. This research showed that the reflectance factor of Japanese larch and Japanese oak reached saturation and that both forest types had different spectral trajectories with stand development. In addition, we found that middle of development stage (stand volume was between 100 and 200 m³/ha) of each forest type had similarity in reflectance factor.     

Chemical structures of the condensed tannins in the fruits of Diospyros species

The structural variety of the condensed tannins (proanthocyanidins) in the fruits of 16Diospyros species are reported. Eleven species contained condensed tannins mostly consisting of a mixture of catechin (CA) and gallocatechin (GCA) repeating units; the other five species did not. The GCA content in the CA-GCA total varied from 0.3% to 84.6%. The number of esterified gallic acid per one flavan repeating unit (degree of galloylation, DG) ranged from 0.01 to 0.89. The GCA content was found to be proportional to the DG values. Thus, 16Diospyros species tested may be classified into five groups by the analytical data of their condensed tannins. It may be interesting to compare their structural characteristics with those of the condensed tannins in other fruits, leaves, woods, and barks from the viewpoint of their biosynthesis and function in the plants.Part of this paper was presented at the 46th Annual Meeting of the Japan Wood Research Society, Tokyo, April 1995