93 research outputs found

    Characterisation of major histocompatibility complex class I genes in Japanese Ranidae frogs.

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    The major histocompatibility complex (MHC) is a key component of adaptive immunity in all jawed vertebrates, and understanding the evolutionary mechanisms that have shaped these genes in amphibians, one of the earliest terrestrial tetrapods, is important. We characterised MHC class I variation in three common Japanese Rana species (Rana japonica, Rana ornativentris and Rana tagoi tagoi) and identified a total of 60 variants from 21 individuals. We also found evolutionary signatures of gene duplication, recombination and balancing selection (including trans-species polymorphism), all of which drive increased MHC diversity. A unique feature of MHC class I from these three Ranidae species includes low synonymous differences per site (d S) within species, which we attribute to a more recent diversification of these sequences or recent gene duplication. The resulting higher d N/d S ratio relative to other anurans studied could be related to stronger selection pressure at peptide binding sites. This is one of the first studies to investigate MHC in Japanese amphibians and permits further exploration of the polygenetic factors associated with resistance to infectious diseases

    Selective constraint acting on TLR2 and TLR4 genes of Japanese Rana frogs

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    Toll-like receptors (TLRs) are an important component of innate immunity, the first line of pathogen defence. One of the major roles of TLRs includes recognition of pathogen-associated molecular patterns. Amphibians are currently facing population declines and even extinction due to chytridiomycosis caused by the Batrachochytrium dendrobatidis (Bd) fungus. Evidence from other vertebrates shows that TLR2 and TLR4 are involved in innate immunity against various fungi. Such genes therefore may play a functional role in amphibian-chytridiomycosis dynamics. Frogs from East Asia appear to be tolerant to Bd, so we examined the genetic diversity that underlies TLR2 and TLR4 from three Japanese Ranidae frog species, Rana japonica, R. ornativentris and R. tagoi tagoi (n = 5 per species). We isolated 27 TLR2 and 20 TLR4 alleles and found that these genes are evolutionarily conserved, with overall evidence supporting purifying selection. In contrast, site-by-site analysis of selection identified several specific codon sites under positive selection, some of which were located in the variable leucine rich repeat domains. In addition, preliminary expression levels of TLR2 and TLR4 from transcriptome data showed overall low expression. Although it remains unclear whether infectious pathogens are a selective force acting on TLRs of Japanese frogs, our results support that certain sites in TLRs of these species may have experienced pathogen-mediated selection

    THE KINETIC LINKAGE IN PITCHING MOTION

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    The objective of this study was to analyze three-dimensional motion chains of pitching movement, and determine how the chains of movement of the limbs were working together from the lower extremities to the upper extremities. There were devided three experimentals group for compareing the motion skills: professional (n=9), amateur (n=9), and high school (n=9) baseball players. The pitching motion recorded for all subjects performed the maximum their effort from the mound for throwing the ball. It was recorded in videotapes by two high-speed cameras to arrange places. Then four points of every picture were digitized per 1/500 second. Three-dimensional coordinates for the segment endpoints were computed by a direct linear transformation (DLT) method. The resultof this study, linking the lower and upper body, professional picher could move the body efficiant and give the speed for ball. on the other hand, it was found that amatur and high school picher could not move the body efficient becouse to move the shoulder of piching side to piching direction

    Clinicopathological significance of CD79a expression in classic Hodgkin lymphoma

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    Classic Hodgkin lymphoma (CHL) is a lymphoid neoplasia characterized by the presence of large tumor cells, referred to as Hodgkin and Reed-Sternberg (HRS) cells, originating from B-cells in an inflammatory background. As the clinical significance of B-cell markers has yet to be fully elucidated, this study aimed to clarify the clinicopathological significance of CD79a in 55 patients with CHL. They were immunohistochemically divided into two groups, comprising of 20 CD79a-positive and 35 CD79a-negative patients. There was no significant correlation between CD79a and CD20 expression (rs = 0.125, P = 0.362). CD79a-positive patients were significantly older at onset (P = 0.011). There was no significant correlation between CD79a-positivity and clinical stage (P = 0.203), mediastinal involvement (P = 0.399), extranodal involvement (P = 0.749), or laboratory findings, including serum levels of lactate dehydrogenase (P = 1) and soluble interleukin-2 receptor (P = 0.251). There were significant differences in overall survival (OS) (P = 0.005) and progression-free survival (PFS) (P = 0.007) between CD79a-positive and CD79a-negative patients (5-year OS: 64.6% and 90.5%; 5-year PFS: 44.0% and 76.6%, respectively). Five patients in whom the majority (> 80%) of HRS cells expressed CD79a consisted of 4 males and 1 female aged between 52 and 81 years; 4 of them were in a limited clinical stage. We concluded that CD79a-positive CHL may have unique clinicopathological features

    Inbreeding ratio and genetic relationships among strains of the Western clawed frog, Xenopus tropicalis

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    The Western clawed frog, Xenopus tropicalis, is a highly promising model amphibian, especially in developmental and physiological research, and as a tool for understanding disease. It was originally found in the West African rainforest belt, and was introduced to the research community in the 1990s. The major strains thus far known include the Nigerian and Ivory Coast strains. However, due to its short history as an experimental animal, the genetic relationship among the various strains has not yet been clarified, and establishment of inbred strains has not yet been achieved. Since 2003 the Institute for Amphibian Biology (IAB), Hiroshima University has maintained stocks of multiple X. tropicalis strains and conducted consecutive breeding as part of the National BioResource Project. In the present study we investigated the inbreeding ratio and genetic relationship of four inbred strains at IAB, as well as stocks from other institutions, using highly polymorphic microsatellite markers and mitochondrial haplotypes. Our results show successive reduction of heterozygosity in the genome of the IAB inbred strains. The Ivory Coast strains clearly differed from the Nigerian strains genetically, and three subgroups were identified within both the Nigerian and Ivory Coast strains. It is noteworthy that the Ivory Coast strains have an evolutionary divergent genetic background. Our results serve as a guide for the most effective use of X. tropicalis strains, and the long-term maintenance of multiple strains will contribute to further research efforts

    GENETIC DIVERGENCE AND GEOGRAPHIC DISTRIBUTION OF FROGS IN GENUS FEJERVARYA FROM INDONESIA INFERRED FROM MITOCHONDRIAL 16S rRNA GENE ANALYSIS

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    The Indonesian archipelago is an ideal setting for the study of speciation and biogeography. This archipelago is divided into three island groups based on zoogeography: Sundaland, Wallaceaand the Australian region. In this paper we used frogs in genus Fejervarya (Bolkay) to study biogeography and examine patterns of gene flow across proposed zoogeographic boundaries. Severalmolecular studies on Fejervarya species from Indonesia have been carried out, but comparative studies among members of the genus Fejervarya have yet to be performed. In order to elucidate genetic divergence and geographic distribution of these frogs, we conducted a molecular analysis of the mitochondrial 16S rRNA gene using 179 frogs from five Fejervarya species. In total we collected from 32 localities in Sumatra, Kalimantan (Indonesian part of Borneo), Java, Bali, Sulawesi and Lesser Sunda Islands in Indonesia. Molecular phylogenetic analysis recovered 35 haplotypes and showed that frogs in the genus Fejervarya were divided into two well-supported clades. The first group were of three species, F. limnocharis, F. iskandari and F. cf. verruculosa and the other group clade consisted of Fejervarya cancrivora and Fejervarya sp. (Sulawesi-type). The average sequence divergence among these four species ranged from 1.09 to 16.03% (mean = 11.29±2.83%). The present results clearly show that there are five Fejervarya species in the Indonesian archipelago. Fejervarya limnocharis and F. cancrivora are widely distributed and sympatric in Sumatra, Borneo and Java. Fejervarya iskandari is not endemic to Java and also occurs in the Lesser Sundas. Fejervarya cf. verruculosa and Fejervarya sp. (Sulawesi-type) are endemic to Lesser Sunda and Sulawesi Island, respectively. Key words: Fejervarya, genetic divergence, geographic distribution, 16S rRNA gen

    Genomic structure and evolution of multigene families: “Flowers” on the human genome

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    We report the results of an extensive investigation of genomic structures in the human genome, with a particular focus on relatively large repeats (>50 kb) in adjacent chromosomal regions. We named such structures “Flowers” because the pattern observed on dot plots resembles a flower. We detected a total of 291 Flowers in the human genome. They were predominantly located in euchromatic regions. Flowers are gene-rich compared to the average gene density of the genome. Genes involved in systems receiving environmental information, such as immunity and detoxification, were overrepresented in Flowers. Within a Flower, the mean number of duplication units was approximately four. The maximum and minimum identities between homologs in a Flower showed different distributions; the maximum identity was often concentrated to 100% identity, while the minimum identity was evenly distributed in the range of 78% to 100%. Using a gene conversion detection test, we found frequent and/or recent gene conversion events within the tested Flowers. Interestingly, many of those converted regions contained protein-coding genes. Computer simulation studies suggest that one role of such frequent gene conversions is the elongation of the life span of gene families in a Flower by the resurrection of pseudogenes

    Biological Safety of Fish (Tilapia) Collagen

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    Marine collagen derived from fish scales, skin, and bone has been widely investigated for application as a scaffold and carrier due to its bioactive properties, including excellent biocompatibility, low antigenicity, and high biodegradability and cell growth potential. Fish type I collagen is an effective material as a biodegradable scaffold or spacer replicating the natural extracellular matrix, which serves to spatially organize cells, providing them with environmental signals and directing site-specific cellular regulation. This study was conducted to confirm the safety of fish (tilapia) atelocollagen for use in clinical application. We performed in vitro and in vivo biological studies of medical materials to investigate the safety of fish collagen. The extract of fish collagen gel was examined to clarify its sterility. All present sterility tests concerning bacteria and viruses (including endotoxin) yielded negative results, and all evaluations of cell toxicity, sensitization, chromosomal aberrations, intracutaneous reactions, acute systemic toxicity, pyrogenic reactions, and hemolysis were negative according to the criteria of the ISO and the Ministry of Health, Labour and Welfare of Japan. The present study demonstrated that atelocollagen prepared from tilapia is a promising biomaterial for use as a scaffold in regenerative medicine
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