CYTOLOGIA
Online ISSN : 1348-7019
Print ISSN : 0011-4545
Volume 61, Issue 3
Displaying 1-14 of 14 articles from this issue
  • S Sanchez, A. S. Fenocchio
    1996 Volume 61 Issue 3 Pages 247-252
    Published: September 25, 1996
    Released on J-STAGE: November 09, 2009
    JOURNAL FREE ACCESS
    We studied cytogenetically a population of Callichthys callichthys from Argentina. It showed three different cytotypes. The basic chromosome number observed in this population was 2n=56. The presence in some individuals of one or two metacentric accesory chromosomes originated polymorphic forms with 2n=57 (56+1) and 2n=58 (56+2). C-bands were observed in centromeric and pericentromeric regions. The NORs were located in terminal position in the short arms on a ST chromosome pair. The successive aplication of these techniques evidence the correlation between NORs and constitutive heterochromatic regions.
    On the basis of available data we suggest that 2n=56 may be the basic chromosome number for Callichthys callichthys. All the different cytotypes described at the present could be derivated forms.
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  • William A. Berzonsky
    1996 Volume 61 Issue 3 Pages 253-258
    Published: September 25, 1996
    Released on J-STAGE: November 09, 2009
    JOURNAL FREE ACCESS
    Presence of a quadrivalent at meiosis in allohexaploid wheat (Triticum aestivum L.) can indicate a heterozygous reciprocal chromosome translocation. Such a translocation has significant genetic consequences. This study was initiated to determine the source and trace the inheritance of a heterozygous reciprocal translocation in 'Atlas 66' wheat. Meiotic analyses of hybrids between 'Frondoso', the Brazilian parent of 'Atlas 66', and 'Chinese Spring' ditelosomic lines suggest 'Frondoso' carries the same 2A/2D translocation as 'Atlas 66'. Because of this and because 'Frondoso' is a parent of 'Atlas 66', 'Frondoso' is the probable source of the 'Atlas 66' translocation. Detection of a 2A/2D translocation in 'Fronteira', the only Brazilian parent of 'Frondoso', traces this chromosome interchange to an earlier Brazilian origin. Six of nine varietal derivatives of 'Frondoso' ( 'Atlas 50', 'Coastal', Wakeland', 'Key', 'Laura', and 'Karl') formed a ring or a chain quadrivalent at meiosis. Frequencies of quadrivalents and the proportion of rings versus chains depended on the variety, irrespective of the genetic closeness of a variety to 'Frondoso'. Meiotic analyses suggest these varieties also carry a 2A/2D translocation. Trivalent-formation in aneuploids was considered evidence that non-cooriented segregations from quadrivalents occurred. Production of aneuploids could impact genetic studies and breeding when these varieties are used.
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  • G. A. Malallah, M. Afzal, T. A. Attia, D. Abraham
    1996 Volume 61 Issue 3 Pages 259-267
    Published: September 25, 1996
    Released on J-STAGE: November 09, 2009
    JOURNAL FREE ACCESS
    A detailed cytological study of tapetum tissue accompanied by micrographic confirmation has been performed in a high number of cells in the four plant species, Launaea mucronata, Picris babylonica, Senecio glaucus and Sonchus oleraceus. While in these species, all tapetal cells were binucleated as a result of an obligatory first acytokinetic mitosis, in two species this was followed by a second division forming tetranucleated cells and in the other two species a further third division followed to form octanucleated cells. Existence of variable percentages of tapetal cells with other numbers of nuclei has been documented and interpreted. Similarly endopolyploidy phenomena was found to be of general occurrence in all four species. Its possible origin and significance for the developing microspores has been stipulated. Diagrammatic illustrations are insinuated to elucidate the possible origin of nuclei having variable ploidy levels and sizes. These illustrations have been based mainly on fusion of neighboring chromosomal groups, an inhibition of spindle formation or incidence of persisting chromatid bridges which could prevent proper separation of chromatids.
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  • Seiichi Sato, Miyuki Yamada
    1996 Volume 61 Issue 3 Pages 269-276
    Published: September 25, 1996
    Released on J-STAGE: November 09, 2009
    JOURNAL FREE ACCESS
    Actively growing root tips of Vicia faba excised to about 5 mm length were exposed to hypoxia and the structure of nucleoli were examined under electron microscopy. The nucleolar segregation was first discerned under hypoxia. Then, the fibrillar centers (FCs) enlarged at the 4th hr, accompanying many unusual granules about 35 nm in diameter (35 nm granules). Most FCs appeared as a channel-like configuration at the 4th and 8th hr. The 35 nm granules became ambiguous toward the 8th hr. In parallel with development of the FCs, the GC dispersed into the space between dense chromatin masses. Then, collapse of the DFC followed and eventually, the FCs coated with thin layer of the DFC were exposed. In the control specimens, the FCs also developed a little. However, no 35 nm granule arose in the FCs and no conspicuous degradation of the nucleoli occurred. These results strongly suggest that the hypoxic shock lowers the rate of rRNA synthesis to retract active rRNA genes from the DFC, leaving some nucleolar proteins in the FCs as the 35 nm granules.
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  • A. Stefani, N. Colonna
    1996 Volume 61 Issue 3 Pages 277-283
    Published: September 25, 1996
    Released on J-STAGE: November 09, 2009
    JOURNAL FREE ACCESS
    In order to characterize the reproductive biology of Dasypyrum villosum (an allogamous Graminease, 2n=14) and to establish its tolerance to temperature variability, the duration and regularity of meiotic process and microspore growth, in natural and controlled condition, have been examined. We have investigated meiosis behaviour in a temperature range from 5 to 35°C and we observed that high temperatures reduce meiosis duration while low temperatures increase its duration over five days; the meiotic process shows few abnormalities in both conditions with production of non-reduced gametes after low temperature treatments and contracted chromatin after heat treatments. In our experimental conditions the growth of the microspores is directly correlated to the temperature and no reduction of fertility has been observed.
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  • Ahmed E. Yaseen, F. M. Mostafa, I. S. Kawashti
    1996 Volume 61 Issue 3 Pages 285-295
    Published: September 25, 1996
    Released on J-STAGE: November 09, 2009
    JOURNAL FREE ACCESS
    Chromosomes in five species of the order Dictyoptera Periplaneta americana, Blattella germanica, Supella supellectilium, Mantis religiosa and Sphadromantis bioculata have been studied. In Periplaneta americana (Family Blattidae), the diploid chromosome number of 32+XX in Females and 32+XO in males was observed, while the diploid chromosome number in the two species Blattella germanica and Supella supellectilium (Family Blattillidae) were 22+XX in female, 22 + XO males and 18+XX in females, 18+XO in males respectively. The diploid chromosome number for the two species Mantis religiosa and Sphadromantis bioculata (Family Mantidae) were determined to be 26+XX in females, 26+XO in males and 22+XX in females, 22+XO in males respectively. Karyotypic data for these five species had been studied in details. These results are reported for the first times in Egypt.
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  • S. Sinha, B. Debnath, R. K. Sinha
    1996 Volume 61 Issue 3 Pages 297-300
    Published: September 25, 1996
    Released on J-STAGE: November 09, 2009
    JOURNAL FREE ACCESS
    Chromosome studies and in situ estimation of 4C nuclear DNA content were made on dioecious Momordica cochinchinenesis (Lour.). Somatic chromosome number 2n = 28 was found to be constant in both sexes. Karyotype analysis revealed a very high homogenity. Chromosomes are usually short and with median and submedian constrictions. DNA content did not show marked variation and no correlation could be obtained between the amount of 4C DNA and total chromosome length. However, the relation between DNA content and total chromosome length was discussed in the light of average packing ratio.
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  • Marta S. Ojeda, Laura E. Torres
    1996 Volume 61 Issue 3 Pages 301-306
    Published: September 25, 1996
    Released on J-STAGE: November 09, 2009
    JOURNAL FREE ACCESS
    The objective of this paper is to record the results of the study to make the karyotyping characterization of five S. indicus populations from Argentina by using Image Analysis System (IAS).
    The objective of this study was to make the karyotyping characterization of 5 S. indicus populations from Argentina by using the Image Analysis System (IAS). This native grass species has 2n = 36 according to previous records, the karyotype is composed of 13 metacentric pairs and 5 submetacentric pairs; pair N° 2 has terminal satellites at the short arms. The mean chromosome length in 1.16 μm ranging from 0.76 to 1.61 μm. To determine the chromosome parameters the measurements were analyzed using the image analysis system. No cytotype differences were found throughout the populations analyzed.
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  • Abdul Mujeeb-Kazi, M. N. Islam-Faridi, Alejandro Cortés
    1996 Volume 61 Issue 3 Pages 307-315
    Published: September 25, 1996
    Released on J-STAGE: November 09, 2009
    JOURNAL FREE ACCESS
    Fluorescent in situ hybridization (FISH) diagnostic methodology was applied to hybrids between Thinopyrum elongatum/Secale cereale, and to some amphiploids or backcross (BC) derivatives of Triticum aestivum with Aegilops variabilis, Th. bessarabicum, Th. curvifolium, Th. scirpeum and Th. elongatum. The alien species are resistance/tolerance sources to biotic/abiotic stresses, and are being utilized for transfer of these traits to T. aestivum. The in situ methodology elucidated mechanisms of doubling of egg cells, provided genomic distinction in F1 hybrids and amphiploids, enabled identification of aneuploidy through chromosomal loss or gain, and facilitated the detection of spontaneously produced wheat/alien chromosomal translocations. The advantage of using alien DNA for blocking and wheat DNA for labelingallowed better genomic differentiation than when the normally reverse routine was adopted. Aneuploidy in amphiploid maintenance (T. aestivum/Ae. variabilis; Th. elongatum/T. aestivum) was also observed.
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  • J-H Xiang, A. J. Courtney, L-H Zhou
    1996 Volume 61 Issue 3 Pages 317-320
    Published: September 25, 1996
    Released on J-STAGE: November 09, 2009
    JOURNAL FREE ACCESS
    Although the fisheries for, and mariculture of, penaeid prawns are of major commercial importance, there has been relatively little research undertaken on the chromosome number, structure and composition in the Penaeidae (Xiang 1988, Xiang et al. 1991). One reason for this is due to the relatively small size and large number of chromosomes, which makes production of histological material difficult.
    In this paper, we report a simple and effective technique for determining chromosome complements during spermatogenesis in two species of penaeid prawns, Penaeus merguiensis and P. esculentus in Australia. The first estimates of the number of chromosomes in these species are given.
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  • A. Uchino, L. Wang
    1996 Volume 61 Issue 3 Pages 321-325
    Published: September 25, 1996
    Released on J-STAGE: November 09, 2009
    JOURNAL FREE ACCESS
    A comparative study of the cold-sensitive segment and C-banded segments of chromosomes was made in Paris tetraphylla (2n = 2x = 10). The cold-sensitive segment was confined to the distal half of the short arm of chromosome C out of five chromosomes A to E. On the other hand, C-bands were not only found in the cold-sensitive segment but also regions of all chromosomes A to E. Thus, it was elucidated that the heterochromatic regions of this species consist of reactive segments to both cold treatment and C-banding staining and only to C-banding staining. The cold-sensitive segments of Paris tetraphylla chromosomes might be AT-rich constitutive heterochromatin.
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  • Yasuhito Kinjo, Masaji Shigeno, Kunio Shinohara, Makoto Watanabe
    1996 Volume 61 Issue 3 Pages 327-336
    Published: September 25, 1996
    Released on J-STAGE: November 09, 2009
    JOURNAL FREE ACCESS
    The fine structure of wet human chromosome/chromatin neither fixed nor stained wasstudied by atomic force microscopy (AFM) in comparison with soft X-ray contact microscopy (XCRM). Fibers with typical knobby appearance and particles of 30-60 nm in diameter within and around the fibers were evidently observed by AFM. Globular clusters of nucleosomes ('moluroid' organization of nucleosomes, superbeads) were observed by XCRM in the specimens prepared in the same way.
    Both data suggested that chromatin fibers are basically composed of various sizes of condensed particles.
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  • Sachihiro Matsunaga, Atsushi Sakai, Shigeyuki Kawano, Tsuneyoshi Kuroi ...
    1996 Volume 61 Issue 3 Pages 337-341
    Published: September 25, 1996
    Released on J-STAGE: November 09, 2009
    JOURNAL FREE ACCESS
    Mature pollen grains from the male and the female flowers of Actinidia deliciosa (kiwifruit) were examined by DAPI (4', 6-diamidino-2-phenylindole) -fluorescence microscopy. The generative nucleus and the vegetative nucleus were observed in the male pollen grain while neither nucleus was observed in the female pollen grain. In the generative cell of the pollen grains from the male flower, many organelle nuclei were observed. The DNA content of the generative and the vegetative nuclei was measured fluorimetrically by propidium iodide staining with a video-intensified microscope photon counting system. The DNA content of the generative nucleus was about twice as large as that of the vegetative nucleus. This suggests that the generative nucleus has 2C DNA and is arrested in the G2 phase.
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  • Rocío Cid, Guadalupe Palomino
    1996 Volume 61 Issue 3 Pages 343-348
    Published: September 25, 1996
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    Meiotic and mitotic chromosomes were analyzed in plants of three populations of Myrtillocactus geometrizans var. geometrizans (Cactaceae). Plants were diploid, chromosome counts were 2n = 22, n =11 (x =11). Karyotypes showed 11 pairs of metacentric chromosomes. Plants of two populations had the same cytotype, this with satellites in chromosome pair 1, chromosome length of 2.19-3.69 μm, and TCL = 32 μm. A second cytotype has satellites in pairs 1 and 2, chromosome length of 1.75-2.95 μm, and TCL = 25.40 μm. No evidence was detected of structural chromosomal rearrangements.
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