Trends in Childhood Obesity in Japan over the Last 25 Years from the National Nutrition Survey

Objective: To describe the 25‐year changes in BMI (measured in kilograms per meters squared) and the prevalence of obesity in Japanese children with special reference to urban‐rural differences. Research Methods and Procedures: We used the data sets from the cross‐sectional annual nationwide surveys (National Nutrition Survey, Japan) conducted from 1976 to 2000 and comprising 29, 052 boys and 27, 552 girls between 6 and 14 years of age. We carried out the trend analyses with the data on sex and age groups and on residential areas according to the size of the municipality (metropolitan areas, cities, and small towns). Results: The mean (age‐adjusted) BMI increased by +0.32 kg/m² per 10 years in boys and by +0.24 kg/m² per 10 years in girls, increases that were remarkable in small towns. The prevalence of obese boys and girls increased from 6.1% and 7.1%, respectively, in the time‐period 1976 to 1980, to 11.1% and 10.2% in 1996 to 2000. The increasing trend was most evident in 9‐ to 11‐year‐old children of both sexes living in small towns, whereas no changes were observed in girls in metropolitan areas. Discussion: Our data clearly show increasing trends in obesity prevalence in Japanese school children. Degrees of the increasing trends, however, differed across sex and age groups and residential areas, demonstrating a particular phenomenon that girls in metropolitan areas were unlikely to become obese. These epidemiological aspects indicate the priorities for intervention in population strategies to control obesity in children.     

Biosynthesis of branched-chain fatty acids in Bacillus subtilis. A decarboxylase is essential for branched-chain fatty acid synthetase

Branched long-chain fatty acids of the iso and anteiso series are synthesized in many bacteria from the branched-chain alpha-keto acids of valine, leucine, and isoleucine after their decarboxylation followed by chain elongation. Two distinct branched-chain alpha-keto acid (BCKA) and pyruvate decarboxylases, which are considered to be responsible for primer synthesis, were detected in, and purified in homogenous form from Bacillus subtilis 168 strain by procedures including ammonium sulfate fractionation and chromatography on ion exchange, reversed-phase, and gel absorption columns. The chemical and catalytic properties of the two decarboxylases were studied in detail. The removal of BCKA decarboxylase, using chromatographic fractionation, from the fatty acid synthetase significantly reduced its activity. The synthetase activity was completely lost upon immunoprecipitation of the decarboxylase. The removal of pyruvate decarboxylase by the above two methods, however, did not affect any activity of the fatty acid synthetase. Thus, BCKA decarboxylase, but not pyruvate decarboxylase, is essential for the synthesis of branched-chain fatty acids. The very high affinity of BCKA decarboxylase toward branched-chain alpha-keto acids is responsible for its function in fatty acid synthesis.     

Combination of thidiazuron and basal media with low salt concentrations increases the frequency of shoot organogenesis in soybeans [Glycine max (L.) Merr.]

A successful, efficient system for multiple soybean shoot induction of soybean [Glycine max (L.) Merr.] is reported. Multiple shoots were induced from cotyledonary nodes and hypocotyl segments cultured on media supplemented with 2 mg/l thidiazuron (TDZ) or 1.15 mg/l benzyladenine (BA). It was found that TDZ induced adventitious shoots more efficiently than BA and that hypocotyl segments promoted more adventitious shoots than cotyledonary nodes. The optimal TDZ concentrations for shoot organogenesis from hypocotyl segments were between 1 and 2 mg/l. Basal media also influenced the efficiency of shoot organogenesis. The frequency of adventitious shoot formation tended to increase when the salt concentration in the basal media supplemented with 2 mg/l TDZ was reduced. Two media (1/2B5 and 1/2L2) stimulated shoot organogenesis efficiently from hypocotyl segments. This method can thus be advantageously applied in the production of transgenic soybean plants. Received: 3 July 1996 / Accepted: 9 May 1997     

Homogeneity of Borrelia japonica and heterogeneity of Borrelia afzelii and 'Borrelia tanukii' isolated in Japan, determined from ospC gene sequences

Borrelia afzelii, B. japonica, and `B. tanukii' isolated from various sources and geographical origins in Japan were characterized by restriction fragment length polymorphism (RFLP) analysis and sequencing analysis of the outer surface protein C (OspC) amplicon. B. afzelii and `B. tanukii' generated variable RFLP patterns and differences in ospC gene sequence were confirmed. In contrast, 26 isolates of B. japonica generated one OspC RFLP type, and sequence similarity between B. japonica ranged from 96.4 to 99.7%. These finding suggests that B. japonica is unique in comparison with other members of B. burgdorferi sensu lato species with respect to homogeneity of the ospC gene.