Deficiency of membrane-bound dipeptidyl aminopeptidase IV in a certain rat strain

The activity of membrane-bound dipeptidyl aminopeptidase IV (EC 3.4.14.5) was found to be markedly reduced in the Fischer 344 rat strain compared with that in the Wistar strain. Analysis of membrane proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Ouchterlony immunodiffusion revealed the specific absence of this enzyme molecule in the Fischer 344 strain.     

The gene mutated in ataxia-ocular apraxia 1 encodes the new HIT/Zn-finger protein aprataxin

The newly recognized ataxia-ocular apraxia 1 (AOA1; MIM 208920) is the most frequent cause of autosomal recessive ataxia in Japan and is second only to Friedreich ataxia in Portugal. It shares several neurological features with ataxia-telangiectasia, including early onset ataxia, oculomotor apraxia and cerebellar atrophy, but does not share its extraneurological features (immune deficiency, chromosomal instability and hypersensitivity to X-rays). AOA1 is also characterized by axonal motor neuropathy and the later decrease of serum albumin levels and elevation of total cholesterol. We have identified the gene causing AOA1 and the major Portuguese and Japanese mutations. This gene encodes a new, ubiquitously expressed protein that we named aprataxin. This protein is composed of three domains that share distant homology with the amino-terminal domain of polynucleotide kinase 3'- phosphatase (PNKP), with histidine-triad (HIT) proteins and with DNA-binding C2H2 zinc-finger proteins, respectively. PNKP is involved in DNA single-strand break repair (SSBR) following exposure to ionizing radiation and reactive oxygen species. Fragile-HIT proteins (FHIT) cleave diadenosine tetraphosphate, which is potentially produced during activation of the SSBR complex. The results suggest that aprataxin is a nuclear protein with a role in DNA repair reminiscent of the function of the protein defective in ataxia-telangiectasia, but that would cause a phenotype restricted to neurological signs when mutant.     

Cloning by functional expression of platelet-activating factor receptor from guinea-pig lung.

Platelet-activating factor (PAF), a unique phospholipid mediator, possesses potent proinflammatory, smooth-muscle contractile and hypotensive activities, and appears to be crucial in the pathogenesis of bronchial asthma and in the lethality of endotoxin and anaphylactic shock. Despite this, little is known of the molecular properties of the PAF receptor and related signal transduction systems. Although several lines of evidence suggest that activation of the PAF receptor stimulates phospholipase C and subsequent inositol trisphosphate formation through G protein(s), the PAF receptor and calcium channel are reported to show a close relation. As a first approach to cloning lipid autacoid receptors, we have isolated complementary DNA for the PAF receptors. Our strategy involved gene expression in Xenopus laevis oocytes and electrophysiological detection of PAF-induced responses. Sequence analysis indicates that the receptor belongs to the superfamily of G protein-coupled receptors.     

Homogeneous climate variability across East Antarctica over the past three glacial cycles

Recent ice core studies have raised the disturbing possibility that glacial-interglacial climate changes may be non-uniform across Antarctica. These findings have been confined to records from the Ross Sea sector of the continent, but significant deviations in other areas would call into question the widely assumed validity of the climate record obtained from Vostok, East Antarctica, on large spatial scales. Here we present an isotopic profile from a core drilled at Dome Fuji, situated 1,500 km from Vostok in a different sector of East Antarctica. The two records show remarkable similarities over the past three glacial cycles (the extent of the Dome Fuji record) in both large-amplitude changes, such as terminations, interglacials and interstadials and more subtle glacial events, even when the origin of precipitation is accounted for. Our results indicate that Antarctic climate is essentially homogeneous at the scale of the East Antarctic Plateau, possibly as a consequence of the symmetry of the plateau and the adjacent ocean.     

随机过程及对数学金融的应用

本书是2005年3月3—6日在日本Ritsumeikan大学举行的第5届“随机过程及对数学金融的应用”国际学术会议的论文集。该会议始于2001年，每年1次，本次会议邀集了一些国际著名学者及日本数学金融界的几个新秀就随机过程及随机分析在金融数学中的一些应用作了综合讲演，涉及一些中心问题和前沿课题。[第一段]     

Reductive evolution suggested from the complete genome sequence of a plant-pathogenic phytoplasma

The minimal gene set essential for life has long been sought. We report the 860-kb genome of the obligate intracellular plant pathogen phytoplasma (Candidatus Phytoplasma asteris, OY strain). The phytoplasma genome encodes even fewer metabolic functions than do mycoplasma genomes. It lacks the pentose phosphate cycle and, more unexpectedly, ATP-synthase subunits, which are thought to be essential for life. This may be the result of reductive evolution as a consequence of life as an intracellular parasite in a nutrient-rich environment.