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  • 1
    Electronic Resource
    Electronic Resource
    Distribution of acetylcholinesterase activity in the rat embryonic heart with reference to HNK-1 immunoreactivity in the conduction tissue (1994)
    Springer
    Anatomy and embryology 190 (1994), S. 367-373 
    Details
    ISSN: 1432-0568
    Keywords: Acetylcholinesterase ; HNK-1 ; Heart ; Morphogenesis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Acetylcholinesterase (AChE) activity was topographically investigated in the presumptive cardiac conduction tissue regions visualized by HNK-1 immunoreactivity in rat embryos, and AChE-positive cells were examined with the electron microscope. On embryonic day (ED) 14.5, when HNK-1 was most intensely visualized, AChE activity could not be detected enzyme-histochemically in the conduction tissue regions, except in the ventricular trabeculae and part of the AV node. On ED 16.5, however, the AChE activity was clearly demonstrated in some parts of the developing conduction tissue. One exception was the AV node region, where an AChE-positive area was in close proximity to an area showing HNK-1 immunoreactivity but did not overlap. Furthermore, AChE activity was demonstrated predominantly in the ventricular trabeculae, including cardiac myocytes, but was rather weak in the atrium. With the electron microscope, AChE reaction products were observed predominantly intracellulary in both developing conduction tissue cells and developing ordinary myocytes, and no reactivity was found in neuronal components. From ED 18.5 until birth, both AChE activity and HNK-1 immunoreactivity faded away in the conduction tissue. Thus, transient AChE activity in the embryonic heart seems to be different from the developing adult form and may be related to a morphogenetic function in embryonic tissues, as proposed by other authors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00187294
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  • 2
    Electronic Resource
    Electronic Resource
    Effects of injecting fibronectin and antifibronectin antibodies on cushion mesenchyme formation in the chick (1992)
    Springer
    Anatomy and embryology 185 (1992), S. 239-247 
    Details
    ISSN: 1432-0568
    Keywords: Heart ; Endocardial cushions ; Cell migration ; Fibronectin ; Fibronectin peptides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary During heart development in the chick some of the endocardial cells that cover the cushion areas leave the cushion endocardium, seed the underlying cardiac jelly, and are transformed into mesenchyme. Cushion mesenchymal (CM) cells migrate from the endocardium toward the myocardium using the cardiac jelly as substratum. Developing cushions have been microinjected with fibronectin (FN), antifibronectin antibodies (AbFN), and four synthetic peptide probes. Two of these peptides (P7 and P10) contained the sequence Arg-GlyAsp-Ser (RGDS), while the other two (P15 and PColl) did not. Cushion area, individual cell area, cell density, cell orientation and a factor of form were evaluated in both experimental and control cushions. CM cell migration was inhibited by FN and AbFN, only partially inhibited by P10 and unaffected by P7. Cushions injected with P15 and PColl were unaffected. These results can be explained by steric modifications of the extracellular matrix, that may render cardiac jelly nonpermissive for CM cell migration, or by interaction of the substances injected at the endocardial cell surface. Migrating CM cells do not present any preferential orientation in any particular direction. CM cell migration seems to depend upon intrinsic migratory behaviour and the presence of FN at the CM cell surface. The enforcement of the direction of CM cell migration does not appear to rely upon matrix signals but be the result of randomly migrating cells becoming distributed more evenly in the matrix.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00211822
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  • 3
    Electronic Resource
    Electronic Resource
    Actin bundles on the right side in the caudal part of the heart tube play a role in dextro-looping in the embryonic chick heart (1991)
    Springer
    Anatomy and embryology 183 (1991), S. 29-39 
    Details
    ISSN: 1432-0568
    Keywords: Heart ; Morphogenesis ; Actin ; Cytochalasin ; Chick embryo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The role of actin bundles on the heart looping of chick embryos was examined by using cytochalasin B, which binds to the barbed end of actin filaments and inhibits association of the subunits. It was applied to embryos cultured according to New's method. Looping did not occur when cytochalasin B was applied diffusely in the medium. Further, we disorganized actin bundles in a limited part of the heart tube to examine the role of actin bundles in each part in asymmetry formation. A small crystal of cytochalasin B was applied to the caudal part of the heart tube on either the left or right side. The disorganization of actin bundles on the left side resulted in the right-bending of the heart, an initial sign of dextro-looping (normal pattern), and right side disorganization resulted in left-bending. We suggest that actin bundles on the right side of the caudal part of a heart tube generate tension and cause dextro-looping. Embryos whose hearts bent to the right rotated their heads to the right, and embryos with left-bent-hearts rotated their heads to the left. The rotation of the heart tube may therefore decide in which direction the body axis rotates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00185832
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  • 4
    Electronic Resource
    Electronic Resource
    Variations in chloroplast DNA from rice (Oryza sativa): differences between deletions mediated by short direct-repeat sequences within a single species (1993)
    Springer
    Theoretical and applied genetics 86 (1993), S. 579-584 
    Details
    ISSN: 1432-2242
    Keywords: Oryza sativa ; Indica ; Chloroplast DNA ; Deletion ; Direct repeat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In a previous study, we compared chloroplast DNAs (ctDNAs) from four species ofOryza and detected two independent deletions of DNA fragments in the ctDNAs (Kanno and Hirai 1992a). These deletions were genotype-specific variations. Since short direct-repeat sequences were detected at the borders of both deletions, the deletions were apparently the result of intramolecular recombination mediated by these direct-repeat sequences. In the present study, we examined whether or not this type of variation exists within a single species. Ishii et al. demonstrated three types of ctDNA inO. Sativa (1988), and the source of the variations that they identified seemed to be deletions. We determined the precise locations of the deletions and the sequences around them. As expected, our results showed that these variations were the results of deletions that were mediated by short direct-repeat sequences. While the deletions that had been found previously were located on spacer regions, those found in this study were located within open reading frames (ORFs). Northern hybridization analysis showed that one of the ORFs was-transcribed. In the case of this deletion, the amino acid sequence encoded by the C-terminal region of the ORF was altered and the short inverted-repeat sequences downstream of the ORF were deleted. In addition, there were other short inverted-repeat sequences downstream of the altered ORF.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00838712
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  • 5
    Electronic Resource
    Electronic Resource
    Identification and genetic analysis of semidwarfism-related proteins in rice (Oryza sativa L.) (1991)
    Springer
    Theoretical and applied genetics 81 (1991), S. 376-380 
    Details
    ISSN: 1432-2242
    Keywords: Rice ; Oryza sativa ; Embryo protein ; Genetic analysis ; Semidwarfism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary By transferring a semidwarf gene (sd-1) from Taichung Native 1 into a tall Japanese cultivar, Norin 29, through seven backcrosses, a semidwarf near-isogenic line SC-TN1 was obtained. The proteins of the embryo in Norin 29 and SC-TN1 were separated by two-dimensional electrophoresis. Most of the proteins showed the same electrophoretic pattern. However, it was found that there was a difference in the appearance of two basic glycoproteins designated as SRP-1 and SRP-2. These proteins exhibited the same molecular mass, but different isoelectric points. Hybridization results indicated that a single locus controls SRP-1 and SRP-2 with codominant alleles. The gene symbol Srp was given to this locus, with alleles Srp-1 and Srp-2 responsible for SRP-1 and SRP-2, respectively. Srp-2 was found in all of the semidwarf cultivars and lines having sd-1, except a tall cultivar Tsaiyuan-chung. This finding suggests that Srp-2 may be closely linked with sd-1. The amounts of these proteins markedly increased after water absorption of the seed, suggesting that these proteins may be related to the early development of the plant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228679
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  • 6
    Electronic Resource
    Electronic Resource
    Role of vitronectin in embryonic rat endocardial cell migration in vitro (1992)
    Springer
    Cell & tissue research 268 (1992), S. 41-49 
    Details
    ISSN: 1432-0878
    Keywords: Vitronectin ; Endocardial cells ; Cell migration ; Heart ; Rat (Donryu)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Vitronectin is one of the extracellular matrices that mediate cell spreading and attachment in vitro. In the present paper, we demonstrate the involvement of vitronectin in the migration of cushion mesenchymal cells of the embryonic rat heart. Immunohistochemistry established the localization of vitronectin in the myocardial cells and in some of the cushion mesenchymal cells of the truncus arteriosus and atrioventricular canal. In vitro, vitronectin, fibronectin, and collagen type-I revcaled significant stimulating activity for cushion mesenchymal cell migration. The distance migrated by cushion mesenchymal cells cultured on vitronectin, collagen type-I, or both vitronectin and fibronectin was similar, but that on fibronectin was significantly shorter. Following the addition of anti-vitronectin IgG to the medium, the migration distance of cushion mesenchymal cells on fibronectin was remarkably increased. Most explants on vitronectin or on both vitronectin and fibronectin became detached from dishes after the addition of the antivitronectin antibody. Immunostaining revealed that cushion mesenchymal cells cultured on substrata other than vitronectin synthesized vitronectin. From these results, it is suggested that vitronectin is synthesized by myocardial cells and some cushion mesenchymal cells, and that vitronectin inhibits cell movement on fibronectin. This feature of vitronectin may be important in the regulation of the migration of cushion mesenchymal cell in vivo.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00338052
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  • 7
    Electronic Resource
    Electronic Resource
    Immunoreactive atrial natriuretic peptide in the fish heart and blood plasma examined by electron microscopy, immunohistochemistry and radioimmunoassay (1990)
    Springer
    Cell & tissue research 260 (1990), S. 235-247 
    Details
    ISSN: 1432-0878
    Keywords: Atrial natriuretic peptide ; Heart ; Freshwater fish ; Seawater fish ; Immunohistochemistry ; Ultrastructure ; Radioimmunoassay ; Cyprinus carpio (Teleostei) ; Narke japonica (Elasmobranchii) ; Eptatretus burgeri (Cyclostomata)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The immunoreactivity of atrial natriuretic peptide and ultrastructure of cardiocytes were examined in 5 species each of freshwater and seawater teleosts, as well as in 2 species each of elasmobranchs and cyclostomes. Immunoreactivity was strong in the atria of Cyprinus carpio, Anguilla japonica and Conger myriaster, rather weak in atria of Channa maculata, Lepomis macrochirus, Salmo gairdneri, Oplegnathus fasciatus and Eptatretus burgeri, very weak in atria of Pagrus major, Trachurus japonicus and Triakis scyllia, and not detectable in atria of Hexagrammos otakii, Narke japonica and Lampetra japonica. The immunoreactivity of the atrial cardiocytes was generally stronger in freshwater than seawater fish. Ventricular immunoreactivity was detected only in 7 species, always being weaker than that observed in the atrium. Ultrastructurally, however, secretory granules were found in atria and ventricles of all species examined, being more frequent in the former than the latter. By radioimmunoassay, immunoreactive ANP was detected in the extracts of blood plasma and both atrial and ventricular tissues of all species examined. There were no statistically significant differences in the values between freshwater and seawater species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318627
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  • 8
    Electronic Resource
    Electronic Resource
    Molecular characterization of rgp2, a gene encoding a small GTP-binding protein from rice (1993)
    Springer
    Molecular genetics and genomics 237 (1993), S. 187-192 
    Details
    ISSN: 1617-4623
    Keywords: Oryza sativa ; ras superfamily ; rgp1 ; rgp2 ; Small GTP-binding proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We previously reported the isolation of rgp1, a gene from rice, which encodes a ras-related GTP-binding protein, and subsequently showed that the gene induces specific morphological changes in transgenic tobacco plants. Here, we report the isolation and characterization of an rgp1 homologue, rgp2, from rice. The deduced rgp2 protein sequence shows 53% identity with the rice rgp1 protein, but 63% identity with both the marine ray ora3 protein, which is closely associated with synaptic vesicles of neuronal tissue, and the mammalian rab11 protein. Conservation of particular amino acid sequence motifs places rgp2 in the rab/ypt subfamily, which has been implicated in vesicular transport. Northern blot analysis of rgp1 and rgp2 suggests that both genes show relatively high, but differential, levels of expression in leaves, stems and panicles, but low levels in roots. In addition, whereas rgp1 shows maximal expression at a particular stage of plantlet growth, rgp2 is constitutively expressed during the same period. Southern blot analysis suggests that, in addition to rgp1 and rgp2, several other homologues exist in rice and these may constitute a small multigene family.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00282800
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  • 9
    Electronic Resource
    Electronic Resource
    Indica-japonica differentiation in Chinese rice landraces (1993)
    Springer
    Euphytica 74 (1993), S. 195-201 
    Details
    ISSN: 1573-5060
    Keywords: Oryza sativa ; landraces ; varietal differentiation ; hsien and keng ; indica and japonica ; isozymes ; chloroplast DNA (cpDNA) ; Polymerase Chain Reaction (PCR)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Ninety Chinese rice landraces were examined with special reference to the indica-japonica differentiation in terms of traditional criteria, isozyme analysis and PCR analysis of the chloroplast DNA (cpDNA). Cultivars were separated into indica and japonica defined by a discriminant function (Z) based on key characters, as well as by isozyme genotypes. Most indica landraces had chloroplast DNAs with a deletion at the Pst-12 fragment, while most japonica landraces had cpDNAs without the deletion. Two traditionally recognized varietal groups in China, keng and hsien, corresponded largely to the respective japonica and indica revealed in our study. The results obtained in this study showed good agreement for classification of indica and japonica types by the three methods: discriminant analysis by Z value, isozyme analysis, and PCR analysis for cpDNA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040401
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