Structure and stereochemistry of brianolide,a new antiinflammatory diterpenoid from the Okinawan gorgonianBriareum sp.

Summary Brianolide (1), a new antiinflammatory diterpenoid of the briarein class, possessing a substituent at C-12 (R), has been isolated from the Okinawan gorgonianBriareum sp. Its structure has been established from spectral data in conjunction with a single crystal X-ray analysis.     

Immigration of lymphoid precursor cells into the thymic rudiment inXenopus

Summary The origin of thymic lymphocytes was investigated, using a new reliable method to mark cells inXenopus. It was easily observed that extraneous cells immigrated into the thymic rudiment 4 days after fertilization and differentiated into a cell population identified as thymic lymphocytes in a fully developed thymus. Clearly, lymphoid precursor cells are of extrinsic origin.This work was supported in part by a grant from the Ministry of Education, Science and culture of Japan (No. 59770026).     

日本传统“诗吟”中单个反射声优选时延与自相关函数的关系

研究在日本传统“诗吟”表演中，在干信号中加上适当时延的单个反射声是否更为有利．专业“诗吟”表演者嗓音中对典型的“节”的吟唱是该种表演艺术的一种独特的吟咏方式．对此及对“节”外内容的吟唱都在消音室中加以录音．文中通过成对比较法试验得出了主观优选的标度值．结果表明，在聆听对“节”的吟唱时，听者更喜欢在干信号中加上延时为10～30ms的单个反射声，而在聆听对“节”外内容的吟唱时，加上单个反射声与否对听者而言并无显著的差别．文中对此项发现从吟唱“节”的声源信号的自相关函数的包络特征上加以讨论．     

Sequence and analysis of chromosome 5 of the plant Arabidopsis thaliana

The genome of the model plant Arabidopsis thaliana has been sequenced by an international collaboration, The Arabidopsis Genome Initiative. Here we report the complete sequence of chromosome 5. This chromosome is 26 megabases long; it is the second largest Arabidopsis chromosome and represents 21% of the sequenced regions of the genome. The sequence of chromosomes 2 and 4 have been reported previously and that of chromosomes 1 and 3, together with an analysis of the complete genome sequence, are reported in this issue. Analysis of the sequence of chromosome 5 yields further insights into centromere structure and the sequence determinants of heterochromatin condensation. The 5,874 genes encoded on chromosome 5 reveal several new functions in plants, and the patterns of gene organization provide insights into the mechanisms and extent of genome evolution in plants.     

Supernormal responses to premature stimulation in Ca-dependent action potentials.

The responses of Ca-dependent action potentials to premature stimulation were studied in the isolated canine ventricular muscle. When very premature stimuli were applied, supernormally augmented responses with propagation occurred, while responses with long preceding intervals were small and not conducted.