A unique vacuolar processing enzyme responsible for conversion of several proprotein precursors into the mature forms

AbstractProprotein precursors of vacuolar components are transported from the endoplasmic reticulum into vacuoles, where they are proteolytically processed into their mature forms. However, the processing mechanism in plant vacuoles is very obscure. Characterization of a purified processing enzyme is required to determine whether a single enzyme is responsible for processing many vacuolar proteins with a large variability of molecular structure. If this is true, how can it recognize the numerous varieties of processing sites? We have now purified a processing enzyme (Mt=37 000) from castor bean seeds. Our results show that the purified enzyme can process 3 different proproteins isolated from either the endoplasmic reticulum or transport vesicles in cotyledon cells to produce the mature forms of these proteins which are found at different suborganellar locations in the vacuole: the 2S protein found in the soluble matrix, the 11S globulin found in the insoluble crystalloid and the 51 kDa protein associated with the membrane. Thus a single vacuolar processing enzyme is capable of converting several proprotein precursors into their respective mature forms

Deformation Bands in Calcite and Quartz Crystals

Deformation bands in some of calcite and quartz grains in a naturally deformed calcite-quartz vein found in the Sangun metamorphic formation near the Kawayama mine, Yamaguchi Pref., Western Japan, have been described. The deformation bands in calcite are inclined at moderate angles to the active glide plane, a {0112} plane (e1), and the axis of the lattice rotation in the band is parallel to the glide plane and normal to the glide direction, the edge [e1: r3]. The angle between the c-axis of the host crystal and the surface of the band boundary is between 14° and 44°, and the angle between the glide direction and the surface of the band boundary is between 40° and 70°. For many of the deformation bands the lattice in the band approaches the completely twinned condition for e1, while in the host crystals the lattice is about 10 per cent twinned on e1. The sense of lattice rotation in the band is opposed to that for twin gliding on e1. The maximum value of the angle of lattice rotation in the band is 87°. Generally, the band boundaries are distinctly displayed by the sharp change in the trend of e1 and in the degree of e1 twinning, but not by such a manner as that e1 twinning progressively increases toward the margins of the band. For the deformation bands, in which the angle of lattice rotation exceeds 44°, the band boundaries are commonly displayed as a sharp discontinuous plane whose crystallographic location can be directly measured by the U-stage. The crystallographic location of the deformation bands in quartz has been tentatively determined on the basis of assumption that the rotational axis of shift in the lattice orientation from the host to the band coincides with either the a-axis or the a*-axis. At this time many of the quartz deformation bands are inclined at high angles to the c-axis. They are approximately tautozonally oriented and are grouped in two sets of planes in the system concerned. The rule for establishing the directions of the principal stresses developed in the system concerned during the deformation related to the formation of the deformation bands, previously introduced by the senior author (1961a and 1963), has been successfully used also for the present specimen. It has been clarified that the sense of lattice rotation in the band for quartz deformation bands is opposed to that for the calcite deformation bands of the present type in the same stress system.今村外治教授退官記念特集

Integrated Approaches to Drug Discovery for Oxidative Stress-Related Retinal Diseases

Excessive oxidative stress induces dysregulation of functional networks in the retina, resulting in retinal diseases such as glaucoma, age-related macular degeneration, and diabetic retinopathy. Although various therapies have been developed to reduce oxidative stress in retinal diseases, most have failed to show efficacy in clinical trials. This may be due to oversimplification of target selection for such a complex network as oxidative stress. Recent advances in high-throughput technologies have facilitated the collection of multilevel omics data, which has driven growth in public databases and in the development of bioinformatics tools. Integration of the knowledge gained from omics databases can be used to generate disease-related biological networks and to identify potential therapeutic targets within the networks. Here, we provide an overview of integrative approaches in the drug discovery process and provide simple examples of how the approaches can be exploited to identify oxidative stress-related targets for retinal diseases

On the Difference in Deformation Behaviour between Phenocryst and Ground-mass Quartz of Deformed Rhyolite Pebbles in the Oboke Conglomerate Schist

Quartz subfabrics of the conglomerate schist consisting of rhyolite pebbles and psammitic matrix of the Oboke district, Shikoku, Southwest Japan, have been described and discussed in detail, with special reference to deformation mechanisms of quartz taking place under metamorphic conditions. Quartz grains in the deformed rhyolite pebbles and the psammitic matrix occur generally in two distinctly separated sizes, that is, porphyritic grains of phenocryst quartz in rhyolite and clastic megacryst in psammitic matrix, and fine-grained quartz smaller than one tenth of the former in size, derived from glassy or cryptocrystalline material of the ground-mass of rhyolite and from very fine-grained material of psammitic matrix. The fine-grained quartz grains, except for those surrounding the porphyritic quartz grains, show clearly preferred lattice and dimensional orientation in such a fashion as are symmetrically consistent with the mesoscopic structures of the conglomerate schist of the district. The patterns of lattice and dimensional subfabrics of the fine-grained quartz are essentially the same as those of calcite in the rhyolite pebbles, and the former is symmetrically consistent with the latter. While, for the porphyritic quartz in the rhyolite pebbles and psammitic matrix no preferred lattice orientation has been recognized. The pattern of dimensional orienta-tion of those grains is quite different from that of the fine-grained quartz. The significance of difference in pattern of lattice and dimensional subfabrics between the fine-grained quartz and the porphyritic quartz has been discussed. It is assumed that, when metamorphic deformation induced preferred lattice and dimensional orientations to the fine-grained quartz, deformation of the porphyritic quartz occurred by translation gliding on a certain crystallographic plane, accompanied with the formation of kink bands and recrystallization in those bands and grain-boundaries, though no preferred lattice and dimensional orientations were induced to those coarse-grained quartz grains. Obtained data inclines our mind to such a view that for the deformation of quartz taking place under metamorphic conditions diffusion mechanisms, including nucleation, grain-boundary migration and Riecke diffusion, play the more predominant role than translation gliding on some particular crystallographic planes does. In the Sambagawa crystalline schists of the higher metamorphic grade (e.g., the zone IV in the Kôtsu-Bizan district after Iwasaki, 1963) than that for those of the Oboke district (corresponding to the zone II in the Kôtsu-Bizan district), quartz grains with the average size, which is nearly equal to that of the porphyritic quartz grains in question (no preferred lattice orientation), show a preferred lattice orientation, whose pattern is essentially the same as that of the c-axis subfabric of the fine-grained quartz in question. The average size of quartz grains, which show preferred lattice orientation, increases with increase in the metamophic grade, giving an equilibrium size under any metamorphic deformation condition

Arabidopsis ECHIDNA protein is involved in seed coloration, protein trafficking to vacuoles, and vacuolar biogenesis

Flavonoids are a major group of plant-specific metabolites that determine flower and seed coloration. In plant cells, flavonoids are synthesized at the cytosolic surface of the endoplasmic reticulum and are sequestered in the vacuole. It is possible that membrane trafficking, including vesicle trafficking and organelle dynamics, contributes to flavonoid transport and accumulation. However, the underlying mechanism has yet to be fully elucidated. Here we show that the Arabidopsis ECHIDNA protein plays a role in flavonoid accumulation in the vacuole and protein trafficking to the vacuole. We found defective pigmentation patterns in echidna seed, possibly caused by reduced levels of proanthocyanidins, which determine seed coloration. The echidna mutant has defects in protein sorting to the protein storage vacuole as well as vacuole morphology. These findings indicate that ECHIDNA is involved in the vacuolar trafficking pathway as well as the previously described secretory pathway. In addition, we found a genetic interaction between echidna and green fluorescent seed 9 (gfs9), a membrane trafficking factor involved in flavonoid accumulation. Our findings suggest that vacuolar trafficking and/or vacuolar development, both of which are collectively regulated by ECHIDNA and GFS9, are required for flavonoid accumulation, resulting in seed coat pigmentation

Early Detection of Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is a unique disease with a clinical presentation, epidemiology, and histopathology differing from other squamous cell carcinomas of the head and neck. NPC is an Epstein-Barr virus-associated malignancy with a marked racial and geographic distribution. Specifically, it is highly prevalent in southern China, Southeast Asia, and the Middle East. To date, most NPC patients have been diagnosed in the advanced stage, but the treatment results for advanced NPC are not satisfactory. This paper provides a brief overview regarding NPC, with the focus on the early detection of initial and recurrent NPC lesions

Fatal accidental asphyxia

Accidental death from postural or positional asphyxia can occur when an individual’s body compromises their respiration. The diagnosis of positional asphyxia is usually based on circumstantial evidence supported by the absence of other significant underlying causes of death. A female in her twenties was found dead in the so-called bridge position on a chair with wheels. Her jacket had rolled under one of the chair’s wheels. She was 159 cm in height and weighed 28.8 kg. Her body mass index was 11.4 (she was severely emaciated), and her muscles, including the rectus abdominis muscle, were thin. Her head, face, and neck were markedly congested. Her lungs, especially the upper lobes, were also congested. A small quantity of left cardiac blood was detected, which was slightly coagulated. The right cardiac blood was liquid (21 ml), and the right ventricle was slightly enlarged. It was suggested that the circulation from the lungs to the heart had been restricted. Toxicological tests detected psychoactive agents in the deceased’s blood and urine. The concentration of one of them, tofisopam, was slightly higher than normal. It was suggested that the effects of tofisopam and the deceased’s poor physical condition had impaired her motility, trapping her in an abnormal body position, ‘the reverse jack-knife position’. Therefore, her manner of death was considered to be accidental positional asphyxia. We should be aware that chairs with wheels can occasionally cause such accidents