Comparative study of proteins recovered from whole North Pacific krill Euphausia pacifica by acidic and alkaline treatment during isoelectric solubilization/precipitation

North Pacific krill is widely distributed in the waters around Japan, however its utilization for human consumption has been limited due to its small size. We have investigated the proximate composition, the amino acid, free fatty acid, mineral and protein composition, respectively, as well as the residual proteolytic activity of krill protein, as recovered by acidic- and alkaline-aided isoelectric solubilization/precipitation, in order to facilitate effective utilization of this krill species. Krill protein yield was 31.7 and 73.4 % by acidic and alkaline treatment, respectively. Both treatments resulted in a comparable higher content of essential amino acids than that in whole krill, accompanied with effective removal of insoluble materials. Three major proteolytic active bands with molecular weights of approximately 28, 18 and 16 kDa, as estimated by gelatin-based zymography, were detected. Pronounced residual proteolytic activity was observed in the krill protein after alkaline processing, implying the possible involvement of proteinase(s) in protein degradation during alkaline solubilization. Based on these results, we suggest that inhibition of proteolysis during isoelectric solubilization/precipitation is required for the effective use of North Pacific krill.     

Effect of organic salts on setting gels and their corresponding acids on kamaboko gels prepared from squid Todarodes pacificus mantle muscle

The present study evaluated the quality of setting gels prepared by adding sodium acetate, sodium gluconate, sodium citrate, and sodium succinate to Todarodes pacificus mantle muscle meat, and of the acid-induced kamaboko gels produced by soaking the setting gels in their corresponding acid solutions. The breaking strength was the lowest for the setting gel treated with sodium acetate. The pH values of the acid-induced kamaboko gels decreased when soaked in acid, whereas their moisture contents, whitenesses, and breaking strengths increased. The citric acid-induced kamaboko gel had the highest whiteness index and breaking strength among the gels. The sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) patterns did not show large differences among the gels, except for a low-intensity polymer band in the gluconic acid-induced kamaboko gel. Sodium citrate combined with citric acid yielded the best-quality acid-induced kamaboko gel among all the combinations, so this condition was used to study the effect of organic salt levels. The breaking strength increased when a sodium citrate level of up to 3% was used for the sodium citrate-treated setting gel, and 10% for the citric acid-induced kamaboko gel. The SDS-PAGE patterns did not differ among the sodium citrate levels. Egg white and microbial transglutaminase were necessary for citric acid-induced kamaboko gel production.     

Comparison of Nitrogen Dry Deposition on Cedar and Oak Leaves in the Tama Hills Using Foliar Rinsing Method

Water, Air, & Soil Pollution - Heavy metals and organochlorine residues were determined in water, sediment, fish muscle, and freshwater shrimps from aquatic environments in urban and peri-urban...     

Nickel-catalyzed carbonization of wood for coproduction of functional carbon and fluid fuels II: improved fuel quality of oil fraction and increased heating value of gas fraction

The yields and properties of oil and gas fractions coproduced during carbonization of larch wood loaded with Ni 2%, Ni 2%+Ca 1%, and Ni 4% and without catalyst (None) at 700°–900°C were examined to clarify the catalytic effect in terms of conversion into fluid fuels. The net calorific value of oil occurred mainly below 500°C and increased in the order None < Ni 2% < Ni 4% < Ni 2%+Ca 1%, while the yield decreased in this order. The same order held for the production of gases enriched with hydrogen at 500°–700°C. Even above 800°C, markedly promoted evolution of hydrogen took place for all catalyst systems. These observations confirmed the effectiveness of nickel-catalyzed carbonization at 900°C, particularly Ni 2%+Ca 1%, for both upgrading of oil and gaseous fractions, although the quality of oil was not satisfactory. The catalysis of nickel with and without calcium is discussed on the basis of the modified Broid-Shafizadeh scheme, and the scheme was altered to adapt to the high temperature region where oil was no longer produced. Part of this study was presented at the 14th Annual Meeting of the Japan Institute of Energy, Suita, August 2005, and at the 18th Symposium, Session D, of the Materials Research Society of Japan, Tokyo, December 2007     

Molecular mapping of a gene conferring resistance to Aphanomyces root rot (black root) in sugar beet (<Emphasis Type="Italic">Beta vulgaris</Emphasis> L.)

Caused by Aphanomyces cochlioides Drechsler, Aphanomyces root rot is a serious disease of sugar beet (Beta vulgaris L.), for which sources of resistance are scarce. To identify the segregation pattern of the rare resistance trait found in Japanese sugar beet line ‘NK-310mm-O’, F₁ and BC₁F₂ seedings, drawn from a cross between ‘NK-310mm-O’ and susceptible line ‘NK-184mm-O’, were inoculated with zoospores and their survival evaluated in the greenhouse. Resistance segregation followed was that of a single dominant gene, which was designated Acr1 (Aphanomyces cochlioides resistance 1). Molecular markers tightly linked to Acr1 were identified by bulked segregant analysis of two BC₁F₂ populations. Fourteen AFLP markers linked to Acr1 were identified, the closest located within ±3.3 cM. Three F₅ lines and two BC₂F₁ lines, selected on the basis of their Acr1-AFLP markers, were tested for their resistance to Aphanomyces root rot in a highly infested field. Results indicated that Acr1 conferred significant resistance to Aphanomyces root rot at the field level. Based on its linkage with CAPS marker tk, a representative marker for chromosome III, Acr1 was located on this chromosome. The clear linkage between tk and Rhizomania resistance trait Rz1, suggests the clustering of major disease resistance genes on chromosome III.     

Antigenic and genetic analyses of H5 influenza viruses isolated from ducks in Asia.

The hemagglutinin (HA) of six H5 influenza virus strains isolated from ducks in Japan and China in 1976 to 1996 were analyzed antigenically and genetically. Antigenic analysis using a panel of monoclonal antibodies revealed that the HA of H5 influenza viruses isolated from ducks are antigenically closely related to each other. Phylogenetic analysis indicates that the isolates from ducks in Hokkaido were derived from an ancestor common with the highly pathogenic isolates from chickens and humans in Hong Kong in 1997.     

Effect of setting conditions on mechanical properties of acid-induced Kamaboko gel from squid <Emphasis Type="Italic">Todarodes pacificus</Emphasis> mantle muscle meat

Squid Todarodes pacificus suwari gels, set at various temperatures and times, and acid-induced kamaboko gel, which was prepared by soaking suwari gel in 5% acetic acid for 20 h, were studied to evaluate the mechanical properties that are affected by setting conditions. Unset squid meat paste did not form a gel when soaked in acetic acid. The breaking strength of both suwari gel and acid-induced kamaboko gel showed a tendency to increase with setting temperature and time. SDS-PAGE analysis of suwari gel and acid-induced kamaboko gel, which were set at various temperatures and times, showed that myosin heavy chain (MHC) was observed at 30°C only for the first hour. The intensity of the MHC band at 30°C gradually decreased with setting time, while the intensity of the polymer band gradually increased with setting time. These results suggest that the protein-protein bonds in suwari gel affect the final texture of acid-induced kamaboko gel. Based on the analysis of the mechanical properties, and in consideration of the fact that the purpose of this experiment was to reduce energy usage, the best setting condition was determined to be 40°C for 3 h.