Observation of Coulomb-Assisted Nuclear Bound State of Ξ

In an emulsion-counter hybrid experiment performed at J-PARC, a Ξ^{-} absorption event was observed which decayed into twin single-Λ hypernuclei. Kinematic calculations enabled a unique identification of the reaction process as Ξ^{-}+^{14}N→_{Λ}^{10}Be+_{Λ}^{5}He. For the binding energy of the Ξ^{-} hyperon in the Ξ^{-}-^{14}N system a value of 1.27±0.21 MeV was deduced. The energy level of Ξ^{-} is likely a nuclear 1p state which indicates a weak ΞN-ΛΛ coupling.

Building a setup capable of characterizing large and low-loss optics: "STAR".

We have built a setup called STAR that is capable of characterizing large and very low-loss optics. STAR stands for scattering, transmittance, absorption, and reflectance of the setup's measurement items using 1064 nm laser light, a wavelength in which we are currently interested. Thanks to the design concept in which most of the optical components are shared by each measurement, the system is reasonably compact and can be quickly switched from one measurement setting to another with only minor modification and without offloading the piece to be measured from the setup. The instrument is capable of scanning large areas of 500 mm diameter or larger and can be used for both coated and uncoated optics. It is described here in detail, and the results of some measurements are presented.

The Fitness and Economic Benefits of Rearing the Parasitoid Telenomus podisi Under Fluctuating Temperature Regime.

Successful biological control requires detailed knowledge about the mass rearing conditions of the control agents in order to ensure higher quality of field-released insects. Thus, we investigated whether rearing fluctuating thermal condition would affect the fitness and costs of the parasitoid wasp Telenomus podisi Ashmead (a biocontrol agent used for controlling the Neotropical brown stink bug Euschistus heros (Fabricius)) when compared with parasitoid reared at constant temperature condition, which is commonly used in insect facilities. Parasitoids were reared under either constant (continuous exposure at 25 ± 2°C) or fluctuating temperature conditions (i.e., 30 ± 2°C during day and 20 ± 2°C at night) during four consecutive generations. Our results indicated that tested fluctuating temperature is more suitable for rearing of T. podisi as such temperature condition not only resulted in fitness benefits (e.g., shorter developmental time, longer female longevity, higher fecundity/fertility) but also reduced (approximately 23.5%) the estimated costs for producing the parasitoids. Furthermore, rearing T. podisi under fluctuating temperatures improved tolerance to low constant temperatures (i.e., 20°C) without changing the tolerance to constant high temperatures (30°C) in the fourth generation. Surprisingly, even parasitoids that developed under fluctuating thermal conditions performed better than those reared at constant temperature of 25°C. Collectively, our findings suggest that T. podisi reared under fluctuating thermal condition can tolerate better fluctuating temperatures that normally occur both during long periods of transport and in agricultural ecosystems, which will increase the quality and productivity of mass-reared T. podisi for inundative releases.

A new peltogastrid rhizocephalan parasitising a hermit crab from the Japanese coast: a second species of Dipterosaccus Van Kampen & Boschma, 1925 (Crustacea: Cirripedia).

A new rhizocephalan species of the genus Dipterosaccus Van Kampen & Boschma, 1925, is described from the host hermit crab Calcinus vachoni Forest on the coasts of mainland Japan and the Ryukyu Archipelago. Dipterosaccus shiinoi n. sp. differs from the previously described species, D. indicus Van Kampen & Boschma, 1925, which is redescribed, principally in the morphology of the mantle aperture and the disposition of the receptacle ducts. The distribution ranges of the two species partly overlap and they are sympatric at the same reef site near Okinawa Island. Their differentiation as two distinct species was confirmed by partial sequences of the COI gene. The monophyly of Dipterosaccus is supported by high Bayes posterior possibility and bootstrap values.

Tunic morphology and viral surveillance in diseased Korean ascidians: Soft tunic syndrome in the edible ascidian, Halocynthia roretzi (Drasche), in aquaculture.

'Soft tunic syndrome' causes mass mortality in the edible ascidian Halocynthia roretzi in Korean and Japanese aquaculture. In histopathological comparison, there were no specific differences between diseased specimens from Korea and Japan, indicating that soft tunic syndrome occurring in Korea and Japan is the same disease. No bacterial or protozoan cells were microscopically detected in either healthy or diseased tunics suggesting they are not the direct causes of soft tunic syndrome. Attempts were made to isolate virus from affected ascidians taking into account temperature conditions in which soft tunic syndrome is most prevalent in the field. However, no viruses were isolated from diseased or non-diseased specimens using chinook salmon embryo (CHSE-214), flounder fin (FFN) or epithelioma papillosum cyprini (EPC) cell lines.

Morphological characterization of the tunic in the edible ascidian, Halocynthia roretzi (Drasche), with remarks on 'soft tunic syndrome' in aquaculture.

'Soft tunic syndrome' is a serious problem in the aquaculture of the edible ascidian, Halocynthia roretzi (Drasche), and often leads to mass mortality. Here, we describe the tunic morphology of intact and diseased ascidians to reveal structural differences between them. Morphologically, diseased tunics are not very different from intact tunics, although the former are thinner and softer than the latter. While several types of cells are distributed in the tunic, the cell types and their cytomorphologies were almost identical in both groups. As bacterial/protozoan cells were not found in either intact or diseased tunics, they are not the direct cause of soft tunic syndrome. The most remarkable difference was in the bundles of tunic fibres that compose the tunic matrix; in intact tunics, the thick bundles interlace to form a firm matrix, whereas in soft tunics, the tunic fibres do not form thick bundles. Furthermore, areas of low fibre density were found in diseased tunics. Therefore, soft tunic syndrome probably causes inhibition of bundle formation and degradation of tunic bundles, creating areas of low fibre density, although the causes remain unknown.

Cellulose in the house of the appendicularian Oikopleura rufescens.

By electron diffraction analysis, highly crystalline cellulose I beta was found in the house (a special structure in which the tunicate lives) of the appendicularian Oikopleura rufescens. Cellulose microfibrils 20 nm in width were observed in a random array or highly organized with rectangular spacing of 2 to 10 microns in the house. The bundled cellulose microfibrils formed in the inlet filters, which are highly ordered meshwork structures. This paper provides the first account of the existence of cellulose in the house of an appendicularian. Our findings showed that the house and tunic are homologous tissues among the tunicates, and that the common ancestor of the tunicates (ascidians, thaliaceans, and appendicularians) already possessed cellulose-biosynthetic ability.

Full-sized RanBPM cDNA encodes a protein possessing a long stretch of proline and glutamine within the N-terminal region, comprising a large protein complex.

Previously isolated RanBPM, a Ran-binding protein in the microtubule-organizing center, which had been thought to play a role in Ran-stimulated microtubule assembly, turned out to be a truncated protein. To clarify the function of RanBPM, we cloned the full-sized RanBPM cDNA that encodes a 90 kDa protein, compared to the previously isolated cDNA that encoded a 55 kDa protein. The newly cloned 5' coding region contains a great number of cytidine and guanidine nucleotides, like the CpG island. Thus, full-sized RanBPM cDNA encodes a long stretch of proline and glutamine residues in the N-terminal region. It comprises a protein complex of more than 670 kDa. Ran was detected in this complex when RanBPM and Ran were both ectopically expressed. New antibodies to RanBPM were prepared against three different regions of RanBPM. All of them detected a 90 kDa protein that is predominantly localized both in the nucleus and in the cytoplasmic region surrounding the centrosome, but none of them stained the centrosome. In this context, our previous notion that RanBPM is a centrosomal protein should be discarded. RanBPM is well conserved in the animal kingdom. It may play an important role in uncovering Ran-dependent nuclear events.

Catheter ablation of an epicardial accessory pathway via the middle cardiac vein guided by monophasic action potential recordings.

This report describes a case of permanent junctional reciprocating tachycardia (PJRT) that was ablated via the middle cardiac vein, guided by monophasic action potential recording. The patient was a 63-year-old woman who had been suffering from palpitation for 10 years. ECG during palpitation showed a narrow QRS tachycardia with a long RP interval. Electrophysiological study revealed that this tachycardia was an orthodromic reciprocating tachycardia, via an accessory pathway with a decremental property and a long ventriculoatrial interval (130 ms): PJRT. The earliest atrial activation during tachycardia was detected at the junction of the middle cardiac vein with the coronary sinus. Monophasic action potentials were recorded to confirm that the ablation catheter was in contact with the epicardium.

Novel G proteins, Rag C and Rag D, interact with GTP-binding proteins, Rag A and Rag B.

Rag A/Gtr1p are G proteins and are known to be involved in the RCC1-Ran pathway. We employed the two-hybrid method using Rag A as the bait to identify proteins binding to Rag A, and we isolated two novel human G proteins, Rag C and Rag D. Rag C demonstrates homology with Rag D (81.1% identity) and with Gtr2p of Saccharomyces cerevisiae (46.1% identity), and it belongs to the Rag A subfamily of the Ras family. Rag C and Rag D contain conserved GTP-binding motifs (PM-1, -2, and -3) in their N-terminal regions. Recombinant glutathione S-transferase fusion protein of Rag C efficiently bound to both [(3)H]GTP and [(3)H]GDP. Rag A was associated with both Rag C and Rag D in their C-terminal regions where a potential leucine zipper motif and a coiled-coil structure were found. Rag C and D were associated with both the GDP and GTP forms of Rag A. Both Rag C and Rag D changed their subcellular localization, depending on the nucleotide-bound state of Rag A. In a similar way, the disruption of S. cerevisiae GTR1 resulted in a change in the localization of Gtr2p.

Mutations in the 11-cis retinol dehydrogenase gene in Japanese patients with Fundus albipunctatus.

PURPOSE: To detect mutations in the RDH5 gene encoding 11-cis retinol dehydrogenase in patients from Japan with fundus albipunctatus. METHODS: Polymerase chain reaction and direct genomic sequencing techniques were used to detect mutations of the RDH5 coding exons (exons 2-5) in two unrelated patients with fundus albipunctatus. Selected alleles that altered the coding region or intron splice sites were evaluated further through segregation analysis in the families of the index cases. RESULTS: Two novel RDH5 mutations were identified. One of these was a missense mutation Val264Gly in exon 5, and the other was an in-frame insertion of 3 bp in exon 5. CONCLUSIONS: The data indicate that mutations in RDH5 are the primary cause of fundus albipunctatus.

Tunic morphology and cellulosic components of pyrosomas, doliolids, and salps (thaliacea, urochordata).

The morphology and cellulosic composition of the tunic was studied in pelagic tunicates (3 pyrosomas, 2 doliolids, and 13 salps). The tunic is transparent and gelatinous, consisting of an electron-dense cuticular layer with a fibrous tunic matrix. The thickness and density of the cuticular layer and of the tunic matrix differ from species to species. In some salps, the cuticular layer has numerous minute protrusions that are structurally identical to those found in several ascidians. Free mesenchymal cells (tunic cells) are distributed in the tunic. Whereas the number of tunic cells in the pyrosomas is similar to that in ascidians, there are many fewer tunic cells in doliolids and salps. These differences may be caused by the different functions of the tunic in each group. The existence of cellulose in the tunic was confirmed using electron diffraction in all of the species studied thus far. Their diffractograms indicate that the cellulose microfibrils consist of nearly pure I{beta} of the allomorph. These results show that tunic morphology and cellulosic composition are similar in ascidians and thaliaceans (pyrosomas, doliolids, and salps). The tunic is considered to be a homologous tissue in these animals, and their most recent common ancestor would have possessed this tissue.

Behavior of Hemocytes in the Allorejection Reaction in Two Compound Ascidians, Botryllus scalaris and Symplegma reptans.

In botryllid ascidians, the type of allorejection reaction differs among species. Comparative studies of these different reactions contribute to our understanding of the allorecognition and nonself-rejection system. We studied the morphology of hemocyte behavior during allorejection reactions in two species, Botryllus scalaris and Symplegma reptans, which stand at important points in botryllid phylogeny. In B. scalaris, phagocytes mediated hemocyte aggregation, resulting in interruption of blood flow just after vascular fusion of incompatible colonies. Although previous studies indicate that morula cells (MCs) play a central role in the rejection reaction, the MCs of B. scalaris did not participate in the rejection reaction. Colonies of S. reptans showed two types of allorejection reaction that started at different points in the process of vascular fusion between two colonies. In both types of rejection reaction, the MCs played a central role and behaved similarly to those of all botryllids except B. scalaris and a botryllid from Israel. These observations suggest that the differences in hemocyte behavior and allorecognition site observed in this study reflect the variation in allorejection reactions among botryllids.

RagA is a functional homologue of S. cerevisiae Gtr1p involved in the Ran/Gsp1-GTPase pathway.

Human RagA and RagB is reported to be 52% identical to a putative GTPase of Saccharomyces cerevisiae, Gtr1p. According to the reported nucleotide sequence, we amplified human RagA and RagBs cDNAs from the human B cell cDNA library with PCR. Both cDNAs rescued a cold sensitivity of S. cerevisiae, gtr1-11. Furthermore, we introduced into the cloned human RagA cDNA, the mutation 'T21L' corresponding to the gtr1-11 mutation which has been reported to suppress not only all of rcc1-, temperature-sensitive mutants of Ran/Gsp1p GTPase GDP/GTP-exchanging factor, but also rna1-1, a temperature-sensitive mutant of Ran/Gsp1p GTPase-activating protein. The resulting RagAgtr1-11 cDNA partially, but significantly, suppressed both rcc1- and rna1-1 mutations. These results indicated that RagA and RagBs are functional homologues of S. cervisiae Gtr1p. Interestingly, while wild-type human RagA and RagBs were localized within the cytoplasm, similar to S. cerevisiae Gtr1p, the mutated human RagAgtr1-11 corresponding to a dominant negative form of RagA was distributed in discrete speckles in the nucleus, being localized side by side with SC-35, a non-snRNP of the splicing complex. In contrast, a dominant positive form of RagA, Q66L was localized in the cytoplasm. Thus, RagA was suggested to shuttle between the cytoplasm and the nucleus, depending on the bound nucleotide state.

Transfer of the heart pacemaker during juvenile development in the isopod crustacean Ligia exotica.

Developmental changes in heartbeat pacemaker mechanisms were examined electrophysiologically in the isopod crustacean Ligia exotica. The heartbeat of embryos and early juveniles was myogenic. The heart muscle cells were coupled electrically, and no localized pacemaker activity was found in the heart. In newly hatched juveniles, the cardiac ganglion exhibited no spontaneous activity, although stimulation of the cardiac ganglion produced excitatory junctional potentials (EJPs) in the heart muscle. The myogenic activity of the heart was reset and entrained by the EJPs evoked by ganglionic stimulation. During juvenile development, spontaneous EJPs appeared irregularly in the heart muscle. Later in development, the cardiac ganglion started rhythmic bursting, and each muscle response followed a ganglionic burst discharge and overlapped the EJPs evoked by ganglionic activity. At this point, the activity of the cardiac ganglion was suppressed by application of tetrodotoxin (TTX); however, even in old adults, both muscle activity and the heartbeat continued following TTX application. Heartbeat frequency was lower in TTX-containing saline than in normal saline. These results show that, during juvenile development, the heart pacemaker is transferred from the heart muscle to the cardiac ganglion, which becomes the primary pacemaker and entrains the heart muscle activity to a higher frequency via EJPs.

Transgenic medaka fish bearing the mouse tyrosinase gene: expression and transmission of the transgene following electroporation of the orange-colored variant.

Transgenic fish bearing the mouse tyrosinase gene (mg-Tyrs-J) were produced by transfection into fertilized eggs of the homozygous normal orange-colored variant of medaka fish, Oryzias latipes, by means of electroporation. Of 589 eggs transfected, 38 fish (6%) exhibited brownish wild-type skin pigmentation, which was discernible from control siblings. Light microscopy of the skin from the founders thus generated disclosed that 1) melanization occurred and was restricted to melanophores formed presumably from pre-existing amelanotic melanophores, 2) there was a wide variation in the degree of melanization observed among melanophores, and 3) no melanin deposition was recognized in xanthophores or leucophores. Immunofluorescence using an antibody raised against mouse tyrosinase disclosed that melanophores at varying stages of maturation were reactive. Thus, it was shown that the transgene in medaka fish expressed its action in a cell type-specific manner. Crossing of transgenic founders with homozygous orange-colored variant fish yielded two groups of offspring expressing either the wild-type or the orange-colored skin pigmentation at an approximate ratio of 1:1. Crossing between founders exhibiting wild-type pigmentation yielded only offspring with melanized skin. Skin melanophores in these offspring formed vertical stripes, which are rare in this species. The hereditary basis of melanized skin was demonstrated in matings of F1 progenies, which resulted in similar degrees of melanization over whole skin melanophores. The sum of these findings implied that the transgene is expressed as a dominant character gene and is transmitted through germ cell lines according to the Mendelian law. PCR analysis combined with nested PCR technique strongly suggested that the transgene was integrated into the medaka genome, even though the copy number deduced from gel banding was largely diminished, possibly as a result of fragmentation or instability within the medaka genome.

Two modes of tunic cuticle formation in a colonial ascidian Aplidium yamazii, responding to wounding.

The defensive responses in ascidian tunic were investigated in a colonial ascidian Aplidium yamazii by means of light- and electron-microscopy with special reference to the cuticle formation (restoration) of the tunic. When the tunic was wounded by cutting with a razor blade, the tunic around the wounds shrank to close the wound, and electron-dense fibers appeared and covered the exposed surface of the wound. The tunic shrinkage is probably promoted by the contraction of the cellular network in the tunic. On the other hand, when a part of the tunic was damaged by the injection of distilled water or 5% NaOH, a cuticular boundary appeared in the tunic, separating the damaged and undamaged tunic. Before the completion of the boundary formation, tunic cells gather around the boundary precursor that is formed from the electron-dense fibers. Thus, there are two different modes of defensive response involving cuticle formation in A. yamazii. Although the regulatory mechanism is still uncertain, one or other of the modes should be elicited in response to many damaging stimuli.

Subcuticular Rejection: an Advanced Mode of the Allogeneic Rejection in the Compound Ascidians Botrylloides simodensis and B. fuscus.

Allogeneic rejection between colonies (colony specificity) was described by electron microscopy in two compound ascidians, Botrylloides simodensis and B. fuscus. When two incompatible colonies are brought into contact at their growing edges, the tunic cuticle dissolves and the tunics of the colonies partially fuse. Alloreactive, humoral factors may diffuse to the opposite colony through the partially fusing tunic, and the tunic cells (free cells distributed in the tunic) possibly recognize these factors and induce a rejection reaction. Then, blood cells--mainly morula cells--infiltrate into the tunic, while tunic cells are disintegrating near where the partial fusion of the tunic is occurring. The infiltrating blood cells aggregate, disintegrate, and discharge electron-dense materials in the tunic at the subcuticular regions where the tunics have partially fused. Since the rejection lesion is restricted to the subcuticular area, some regulatory systems may be involved in this restriction. At the end, new walls are formed in the tunic matrix to separate the rejection lesion from the contacting colonies. The new wall is a continuous layer composed of electron-dense fibers and is structurally identical to the regenerating tunic cuticle. The mode of occurrence of colony specificity (Hirose et al., 1994) and the present results indicate that tunic cells are the only allorecognition sites in B. fuscus.