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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 37 (1981), S. 721-722 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron-dense deposits were observed at the bases of the cilia ofParamecium fixed in 1% OsO4 solution containing 2% potassium pyroantimonate. The deposits were shown to contain Ca and Sb by X-ray microanalyzer.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Histochemistry and cell biology 65 (1980), S. 321-323 
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The histochemical localization of alkaline phosphatase in sheep parathyroid gland was investigated using light and electron microscopy. The reaction products of enzyme activity were observed by light microscopy in pericytes. By electron microscopy they were limited to the intercellular spaces between the gland cells, being exclusively confined to the external surface of plasma membrane.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Pflügers Archiv 392 (1982), S. 322-326 
    ISSN: 1432-2013
    Keywords: Ca2+ induced contraction ; Series elasticity ; Shortening muscle ; Skinned muscle fiber ; Stiffness change
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Single fibers from frog sartorius or semitendinosus muscle were mechanically skinned and activated in ATP salt solution containing 10 μM Ca2+ (7°C). After development of an isometric contraction, fibers were released at constant speed (0.03–2.4s−1). During ramp shortening, stiffness was determined from the slope of the tension-length diagram obtained during superimposed quick stretches. Both force and stiffness decreased, as the ramp shortening proceeded and approached a steady value after about 60 ms. An increase in speed of shortening caused a decrease in fiber tension and stiffness and an increase in the ratio of stiffness to tension, suggesting a decrease in both the number of attached crossbridges and in the average force per crossbridge.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1017
    Keywords: Insect-fibrillar muscle ; Cross bridge kinetics ; Actin-Myosin interaction ; Length dependent activation of muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Stretch induced activation and release induced deactivation of single glycerol-extracted insect flight muscle fibres were investigated. The results are interpreted to indicate that the muscle length controls the number of acting cross bridges, whereas their attachment-detachment kinetics in mainly determined by the state of strain of the cross bridges. It is concluded that the net detachment rate of the cross bridges is enhanced if the muscle is released thereby “unloading” the cross bridges. This behaviour of the unloaded cross bridge is a basic postulation of most of the molecular muscle contraction models. 1. The delayed tension rise induced by stretches of different amplitudes could be restored to the level before the stretch by a release to the initial length. 2. The delayed tension decrease induced by a release of moderate (up to δL=1.5% L i)amplitude is quantitatively restored within the delayed increase induced by the restretch to the initial length. 3. Stiffness, which decreased during the delayed tension drop after release, is restored during a delayed stiffness increase effected by a restretch to the initial length. 4. The rate and the extent of the stiffness drop after release increased with increasing amplitude of the release and with increasing temperature. 5. After the deactivation, i.e., after tension and stiffness achieved a new steady level after the release, the attached cross bridges are already in the same state of strain as they were before the release. This finding is interpreted to indicate that within the deactivation phase all cross bridges attached prior the release are replaced by cross bridges attached after the release. 6. The rate of tension and stiffness decay after release does not depend on the absolute muscle length but on the amplitude of the release which induced the deactivation.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Chromosoma 82 (1981), S. 133-141 
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract A plant with 2n = 14 + 1 ring chromosomes was obtained in the progeny of a primary trisomie for chromosome 7 of a two-rowed cultivar, Shin Ebisu 16. The morphological characteristics of the trisomic plants with an extra ring chromosome were similar to the primary trisomic for chromosome 7 (Semierect), which suggests that it originated from this chromosome. The ring chromosomes were not completely stable in mitotic cells because of abnormal behavior. Chromosome complements varied in different plants and in different roots within a plant. Root tip cells and spikes with 2n = 14 and 14 + 2 ring chromosomes were observed on plants with 14 + 1 ring chromosomes. Breakage-fusion-bridge cycle was inferred. The ring chromosome was associated with two normal homologues forming a trivalent in 17.6% sporocytes at metaphase I. The transmission of the extra ring chromosome was 23.1% in the progeny of the plant with 14 + 1 ring chromosomes. Trivalent formation may have been much higher at early prophase stages which were difficult to analyze in barley; only 4 of 120 sporocytes analyzed showed an isolated ring at pachytene. The ring chromosome moved to one pole without separation in 24.7% of the sporocytes at AI, and divided in 27.1% sporocytes giving rise to 8-8 separation. Only 10% of the sporocytes showed bridge formation at AI.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-2665
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 67 (1984), S. 161-170 
    ISSN: 1432-2242
    Keywords: Artificial seed aging ; Barley ; Mitotic and meiotic aberrations ; Pollen and seed fertilities ; Transmission of chromosomal aberrations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Barley (Hordeum vulgare L. ‘Himalaya’) seeds were artificially aged under two storage conditions (32 °C/12% moisture content (m.c.) and 38 °C/18% m.c.) to study the behavior of induced chromosomal aberrations during plant growth. The frequencies of aberrant anaphases at first mitosis in root tips were correlated with loss of germinability. However, after 3 and 5 weeks' growth, aberration frequency declined. In plants grown from artificially aged seeds, the frequency of aberrant anaphases appeared to be stabilized at about 1% after 5 weeks' growth, in spite of the large differences in the frequencies at first mitosis. This suggests that because of their genetic imbalance, cells with chromosomal aberrations induced by seed aging were being excluded during plant growth. Meiotic chromosome configurations at MI were normal (7 II) in all plants studied, although a few precocious separations were found. Meiotic aberrations were found at AI-TI, AII-TII and the tetrad stages in the pollen mother cells of plants grown from the control and artificially aged seeds. However, there were no clear differences among the control and the two aging treatments. It was obvious that some cells with meiotic chromosomal aberrations were lost between the AI-TI and AII-TII stages, and still more between the AII-TII and tetrad stages. The frequency of tetrads with micronuclei in plants produced from artificially aged seeds was the same as in the control. The plants grown from artificially aged seeds showed high pollen fertility (95.2 to 97.0%) and seed fertility (90.1 to 97.2%) which was comparable to the control values (97.4 and 97.9%) respectively, indicating no special effects of seed aging. Anaphase cells of the first mitosis in the next (A2) generation were analyzed to study the transmission of chromosomal aberrations through mitotic and meiotic cell divisions in the A1 generation. Aberrant anaphases in the progeny from the artificially aged seeds were not higher than those of the control progeny. This indicates that the chromosomal aberrations induced by seed aging are not transmitted to the next generation.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 68 (1984), S. 433-439 
    ISSN: 1432-2242
    Keywords: Acrotrisomic, Acrocentric chromosomes ; Cytogenetic linkage mapping ; Barley ; Deficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Three acrotrisomic lines, Triplo IL1S, 3L3S, and 4L4S, each carrying an extra acrocentric chromosome, were used for cytogenetic linkage mapping of barley chromosomes. The cytological structures of the acrocentric chromosome of the three acrotrisomic lines were studied with an improved Giemsa N-banding technique. The long (1L) and short arm (1S) of chromosome 1 had deficiencies of approximately 38% and 65%, respectively. The percentages of deficiencies were 0 and 77.8% for 3L and 3S, and 31.7 and 59.3% for 4L and 4S, respectively. All three genes tested (br, f c , gs3) in 1S and all three genes tested, f8, n and 1k2 in 1L showed a disomic ratio indicating that they are located in the deficient segments. Two genes (a c , yst2) located in the middle segment of 3S in linkage map showed a trisomic ratio, and two others a n , x s showed a disomic ratio. The only gene(f9) tested in 4L showed a trisomic ratio. Two genes (1g4, g1) located in the proximal segment of 4S in the linkage map showed a trisomic ratio, whereas two genes (br2, g13) located distally in 4S showed a disomic ratio, indicating that the breakage occurred between g1 and br2. This experiment demonstrates a new method for physical localization of genes on chromosome segments in material such as barley in which pachytene analysis can not be effectively used for accurate determination of break points in structural changes. Problems associated with this new technique are discussed.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 61 (1982), S. 201-208 
    ISSN: 1432-2242
    Keywords: Telotrisomics ; Linkage ; Chromosome mapping ; Centromere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A total of 37 genetic markers located in chromosomes 2, 3, 4 and 5 were associated with specific arms by means of telotrisomic analysis in five telotrisomics (Triplo 2 L, 2 S, 3 S, 4 S, 5 L) of barley (Hordeum vulgare L.). The genes v, gp (= gp 2), li, gs 5, tr and msg2 showed a trisomic ratio with Triplo 2 L indicating that these genes were on the long arm of chromosome 2. A disomic ratio was obtained for genes wst 4, gs 5, and v with Triplo 2 S, confirming that these genes were on the long arm of chromosome 2(2 L). A disomic ratio was observed for genes e, f(= lg), sk, and gs6 with Triplo 2 L. Two genes, f(= lg) and gs6 showed a trisomic ratio with Triplo 2S. These results indicated that genes e, f(= lg), sk, and gs 6 are on the short arm of chromosome 2 (2S). Since only one telocentric chromosome was available for chromosome 3, 4 and 5, most of the well-mapped marker genes were tested with those telocentric chromosomes. The genes cu 2, uz, wst, als, gs 2, zb,f2, and cer-zn 348 showed trisomic ratio with the telocentric for chromosome 3. These genes were located on the short arm of chromosome 3 (Robertson 1971). This indicated that the telocentric chromosome is for the short arm of chromosome 3(3 S). A disomic ratio was obtained for genes yst, x c, al, yst2, a n, ari-a 6 and x s, indicating that these genes are on the long arm of chromosome 3. Two genes, f9 and K, showed trisomic ratio with the telocentric chromosome for 4, while genes gl(= gl2), br2, yh, lg 3, lg 4 and lk 5 showed disomic ratios. This indicated that the telocentric chromosome is for the short arm of chromosome 4. Two genes, fs 2 and g, were studied with Triplo 5 L. Both showed trisomic ratio, indicating that fs 2 and g are located on Triplo 5 L. The centromere position (C) on chromosome 2, 3 and 4 was thus located as (the left side of C is the short arm and the right is the long arm): chromosome 2: f — sk — gs6 — e — C — gs5 — msg2 — wst4 — v — gp — li — tr; chromosome 3: f2 — cer-zn 348 — uz — gs2 — als — cu2 — wst — zb — C — yst — x c — al — yst2 — a n — ari-a 6 — x s; chromosome 4: f9 — K — C — lg4 — lg 3 — gl2 — br2 — lk5 — yh. The centromere position on chromosome 5 was not precisely located.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 64 (1982), S. 13-24 
    ISSN: 1432-2242
    Keywords: Telotrisomics ; Linkage groups ; Centromere ; Heterochromatin ; Hordeum vulgare L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Seven complete chromosomes and nine telocentric chromosomes in telotrisomics of barley (Hordeum vulgare L.) were identified and designated by an improved Giemsa N-banding technique. Karyotype analysis and Giemsa N-banding patterns of complete and telocentric chromosomes at somatic late prophase, prometaphase and metaphase have shown the following results: Chromosome 1 is a median chromosome with a long arm (Telo 1L) carrying a centromeric band, while short arm (Telo 1S) has a centromeric band and two intercalary bands. Chromosome 2 is the longest in the barley chromosome complement. Both arms show a centromeric band, an intercalary band and two faint dots on each chromatid at middle to distal regions. The banding pattern of Telo 2L (a centromeric and an intercalary band) and Telo 2S (a centromeric, two intercalary and a terminal band) corresponded to the banding pattern of the long and short arm of chromosome 2. Chromosome 3 is a submedian chromosome and its long arm is the second longest in the barley chromosome complement. Telo 3L has a centromeric (fainter than Telo 3S) and an intercalary band. It also shows a faint dot on each chromatid at distal region. Telo 3S shows a dark centromeric band only. Chromosome 4 is the most heavily banded one in barley chromosome complement. Both arms showed a dark centromeric band. Three dark intercalary bands and faint telomeric dot were observed in the long arm (4L), while two dark intercalary bands in the short arm (4S) were arranged very close to each other and appeared as a single large band in metaphase chromosomes. A faint dot was observed in each chromatid at the distal region in the 4S. Chromosome 5 is the smallest chromosome, which carries a centromeric band and an intercalary band on the long arm. Telo 5L, with a faint centromeric band and an intercalary band, is similar to the long arm. Chromosomes 6 and 7 are satellited chromosomes showing mainly centromeric bands. Telo 6S is identical to the short arm of chromosome 6 with a centromeric band. Telo 3L and Telo 4L were previously designated as Telo 3S and Telo 4S based on the genetic/linkage analysis. However, from the Giemsa banding pattern it is evident that these telocentric chromosomes are not correctly identified and the linkage map for chromosome 3 and 4 should be reversed. One out of ten triple 2S plants studied showed about 50% deficiency in the distal portion of the short arm. Telo 4L also showed a deletion of the distal euchromatic region of the long arm. This deletion (32%) may complicate genetic analysis, as genes located on the deficient segment would show a disomic ratio. It has been clearly demonstrated that the telocentric chromosomes of barley carry half of the centromere. Banding pattern polymorphism was attributed, at least partly, to the mitotic stages and differences in techniques.
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