Cytotoxic constituents in the holdfast of cultivated Laminaria japonica

ABSTRACT:     Four steroidal ketones were isolated from the holdfast of cultivated Laminaria japonica . The structures were characterized as ergosta-4,24(28)-diene-3-one (1), ergosta-4,24(28)-diene-3,6-dione (2), stigmasta-4,24(28)-diene-3-one (3) and stigmasta-4,24(28)-diene-3,6-dione (4), by spectral data. Compounds 2 and 4 were shown to be cytotoxic against the MCF-7 human breast cancer cell, and the growth of MCF-7 was inhibited by 96% and 79%, respectively, at 10 µg/mL. It is the first report on the isolation of cytotoxic steroidal ketones from the kelp in the genus of Laminaria.     

Comparative Analysis of Japanese and Foreign Strains of <Emphasis Type="Italic">Ralstonia solanacearum</Emphasis> Based on 16S Ribosomal RNA Gene Sequences

We determined nearly the complete sequences of the 16S ribosomal RNA gene (rDNA) for Japanese strains of R. solanacearum. The comparison of 1471 nucleotide positions separated the Japanese strains into two groups, group 1 with biovars 1, 2, 3 and 4 strains which belonged to race 1, and group 2 with biovar 2 strains corresponding to race 3. Group 1 strains all had identical sequences, and strains representing the four biovars within the group did not differ from each other. Group 2 strains had characteristic nucleotides which differed at seven positions from group 1 strains. Comparative analysis of Japanese and foreign strains based on 16S rDNA sequences showed that Japanese group 1 was closely related to Asian and Australian biovars 3, 4 and 5, and belonged to the known division 1. Japanese group 2 was homogeneous to Indonesian biovars 2 and N2 in subdivision 2b. Since the differences in the nucleotides corresponded to restriction sites for the AluI, RFLP analysis of PCR-amplified 16S rDNA efficiently differentiated not only Japanese group 1 from group 2, but also differentiated three types of foreign strains which differed in biovar and geographic origin. Received 26 July 1999/ Accepted in revised form 19 November 1999     

Black Streak of Edible Burdock Caused by Itersonilia perplexans in Japan

Black streak disease of edible burdock (Arctium lappa L.) has been observed periodically in Hokkaido Prefecture, Japan since 1988. Symptoms appeared initially as small, dark brown to black spots on the leaf veins and petioles. The necrotic spots developed longitudinally along the leaf veins or petioles. Diseased leaf veins or petioles occasionally snapped off at the necrotic lesions. An Itersonilia sp. was isolated from rotting leaf veins and petioles. Laboratory inoculations of edible burdock seedlings using ballistospore suspensions produced typical symptoms observed in nature. The fungus had a feathery mycelium and developed a white to pale cream colony color. The mycelium was composed primarily of branched hyphae with clamp connections at the septa. Ballistospores, formed at the apex of inflated cells, were lunate, ovoid to pyriform. The fungus occasionally produced appressoria, chlamydospores and yeast cells. Based on the morphological characteristics, the causal agent was identified as Itersonilia perplexans Derx. Edible burdock strains were also pathogenic to chrysanthemum and caused petal blight. This report is the first of a foliar disease of edible burdock caused by I. perplexans in Japan. Received 8 April 2002/ Accepted in revised form 26 June 2002     

Comparison of feeding systems: feed cost,palatability and environmental impact among hay‐fattened beef,consistent grass‐only‐fed beef and conventional marbled beef in Wagyu (Japanese Black cattle)

The objective of this article is to compare feed cost, palatability and environmental impacts among feeding systems of high concentrate (HC), high hay (HH) and grass‐only‐fed (Gof) groups. Feed cost was the sum of costs paid for feed intake times the price of feed per kilogram. Palatability was measured by a panel taste test using HH and Gof beef and analyzed for differences. Environmental impacts were calculated based on 1 kg of Japanese beef yield of CO₂ equivalents (eq) and animal end weights at each feeding stage. Results showed that the HH and Gof feeding systems could significantly reduce feed costs by approximately 60% and 78%, respectively, from the HC. In the panel taste test, 50% and 47.50% of panelists indicated that HH beef was ‘extremely delicious’ and ‘acceptable,’ respectively, while 15% indicated that Gof beef was ‘extremely delicious’; 62.50% indicated that Gof beef was ‘acceptable.’ Environmental impacts of each feeding system in terms of CO₂ equivalents (eq) were 9.32, 6.10 and 2.04 tonnes of eq for the HC, HH and Gof, respectively. The HH was an economical system that produced moderate impacts on the environment and had impressive taste.     

Bacterial Wilt of China Aster Caused by Erwinia chrysanthemi

In July 2000, a bacterial wilt was found on China aster (Callistephus chinensis Nees) on Hokkaido, Japan. Bacteriological characteristics of the isolated bacteria were identical to Erwinia chrysanthemi. This is the first report on bacterial wilt of China aster caused by E. chrysanthemi. Received 4 June 2001/ Accepted in revised form 6 September 2001