CYTOLOGIA
Online ISSN : 1348-7019
Print ISSN : 0011-4545
Volume 34 , Issue 1
Showing 1-21 articles out of 21 articles from the selected issue
  • R. N. Misra, S. V. S. Shastry
    1969 Volume 34 Issue 1 Pages 1-5
    Published: March 25, 1969
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Two hybrids between Oryza sativa and O. glaberrima were studied for chromosome pairing at meiosis. In both the hybrids pairing was normal at pachytene. In one of them, desynapsis results in low bivalent formation in diplotene and metaphase stages: The significance of these observations is discussed in relation to the nomenclature of genomes and phylesis.
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  • Martin Borrill, C. P. Carroll
    1969 Volume 34 Issue 1 Pages 6-17
    Published: March 25, 1969
    Released: March 19, 2009
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  • C. Kempanna, B. A. Sathyanarayana Setty
    1969 Volume 34 Issue 1 Pages 18-21
    Published: March 25, 1969
    Released: March 19, 2009
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    Evidence has been gathered of the occurrence of secondary association in E. coracana through the scoring of PMCs based on the number of bivalent groups they had in, as observed from polar view.
    Secondary association results indicate at the polyploid nature of the species with 9 as the possible basic chromosome number. The data available at present preclude, however, the further consideration of the problem concerning the auto- or allopolyploid nature of the species.
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  • N. N. Bhandari, S. L. Tandon, Sarmishtha Jain
    1969 Volume 34 Issue 1 Pages 22-28
    Published: March 25, 1969
    Released: March 19, 2009
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    Cytological studies were carried on two species of Canavalia, C. virosa and C. ensiformis, to understand their relationships.
    Distinct cytological differences were observed in the two species, although the chromosome number was the same (n=11). C. virosa showed normal meiosis, except for the presence of a few univalents, whereas in C. ensiformis cytomixis during the pre-meiotic and meiotic stages was observed. Since only the nucleolus took part in the process of cytomixis, the chromosome number remained constant and subsequent stages of meiosis were normal resulting in fertile pollen grains.
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  • G. Giménez-Martín, I. Meza. J. F. López-Sá ...
    1969 Volume 34 Issue 1 Pages 29-35
    Published: March 25, 1969
    Released: March 19, 2009
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  • J. Medda, A. Bose
    1969 Volume 34 Issue 1 Pages 36-44
    Published: March 25, 1969
    Released: March 19, 2009
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    1. Mitotic indices in the four principal sectors of the developing central nervous system in chick have been studied.
    2. It is found that initially the brain and the spinal cord have more or less similar mitotic indices. Later varied mitotic indices are observed in the different sectors of the central nervous system.
    3. The ependymal layer shows the proliferating property with a mitotic index reaching 1.5 level, but the mantle and the peripheral zones never show the proliferating nature, except the peripheral zone of the hind-brain.
    4. The proliferating property of the ependymal layer gradually becomes diminished with a highly significant regression value.
    5. The implications of the observations have been discussed.
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  • S. S. N. Sinha, M. B. E. Godward
    1969 Volume 34 Issue 1 Pages 45-51
    Published: March 25, 1969
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    The effect of the same dose of γ-rays has been studied on the seeds of two varieties of Lens culinaris as regards chiasma frequency.
    It appeared that variety macrosperma is a derived type and microsperma, the true wild one.
    In variety macrosperma the chiasma frequency is slightly lower than variety microsperma.
    The increase in variance ratio (mainly due to increase in the value of mean square between nuclei) in the flower buds of the plants raised from irradiated seeds is likely to be due to more than one karyotype taking part in the formation of the anthers of the flowers.
    More karyotypes appeared to have taken part in the formation of the bud chimaera at low doses, in comparison with high doses.
    Each plant grown from irradiated seeds had a different chimaeric nature.
    In M2 generation plants appeared to have returned towards normality.
    The variety macrosperma has been affected slightly more at the same dose than variety microsperma.
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  • B. V. Ramana Rao, M. V. Koteswara Rao, A. Sudharsan Raj
    1969 Volume 34 Issue 1 Pages 52-56
    Published: March 25, 1969
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    Mitotic abnormalities in Ornithogalum virens Lindl. were studied by using tritiated thymidine as an internal mutagen. Two concentrations viz., 1.0μCi/ml and 2.0μCi, /ml tritiated thymidine were used in this investigation. The root tips were grown in the isotope solution for 4, 6 and 8 hours respectively and then they were transfered to isotope free nutrient solution for further growth of 6, 12, 18 and 24 hours respectively. Cells were scored at both metaphase and anaphases for various types of chromosomal aberrations. Chromatid and isochromatid breaks, chromatid intrachanges, severe chromosome fragmentation, chromosome rings, binucleate cells, single lagging chromosome at metaphase, tetraploid cells were the important types of aberrations observed. It was noticed that 2.0μCi/ml H3 thymidine concentration has caused a higher frequency of chromosomal aberrations than that of 1.0μCi/ml H3 thymidine concentration.
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  • II. Microtubules and formation of the spindle in root tip cells of higher plants
    Aiko Sakai
    1969 Volume 34 Issue 1 Pages 57-70
    Published: March 25, 1969
    Released: March 19, 2009
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    Studies on the development of spindle fibers were carried out using root meristematic cells of Hyacinthus orientalis and Tradescantia reflexa. Initial spindle fibers (microtubules of about 25m/μ diameter) appear first in the cytoplasm among the mitochondria, plastids and other organelles. During prophase, the polar cap developes around the nucleus. Microtubules gather about the nucleus in the region of the polar cap during prophase. As soon as the continuous nuclear envelope breaks down into fragments during prometaphase the microtubules around the nucleus protrude into the nuclear area. Some of them connect with the kinetochore of each chromosome (formation of chromosomal fibers) and others becomes continuous fibers, running from pole to pole.
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  • I. Dinobryon
    Daniel E. Wujek
    1969 Volume 34 Issue 1 Pages 71-79
    Published: March 25, 1969
    Released: March 19, 2009
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    In this examination of the Chrysophycean alga Dinobryon, a consistent and in some ways unique pattern of cell fine structure has been found. Chromatophores were a prominent feature of the cytoplasm and contain thylakoids, usually of three uniformly separated bands. This is very different from other groups, viz. Euglenophyta (Gibbs 1960), and Rhodophyta (Berkoloff 1962, Bouck 1962) were the thylakoids are two to twelve banded. Why such a configuration is so consistent in the Chrysophyta and none of the other algae can only remain unanswered for the present. Also, the chromatophores were longitudinally oriented, flanking the nucleus with the thylakoids running parallel to their long axis. Additional work on other freshwater Chrysophytes would be helpful in establishing the extent of this uniformity and ultimately, what its relation is to the photosynthetic process.
    The chromatophore envelope consisted of three membranes. The outer membrane was smooth and continuous with the outer membrane of the nucleus; the two inner membranes limit the chromatophore proper. On the surface of the plastid, the two inner membranes divided in the region of the nucleus to allow for the presence of tubules. The exact nature of these tubules appear to be infoldings of the outer chromatophore membrane proper.
    The relationship of the shorter flagellum with the eyespot as reported by Conrad (1938) in Uroglena holds true for Dinobryon. No direct contact through fibrils, microtubules or extended vesicles were noted; however, the closeness of the stigma and whiplash flagellum favors some type of correlation. Cross sections of the basal body did not reveal the 9-pointed star reported in the flagella of other algal genera (Manton 1965).
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  • Natwar Raj Kalla
    1969 Volume 34 Issue 1 Pages 80-89
    Published: March 25, 1969
    Released: March 19, 2009
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    Spermatogenesis in two millipedes Phyllogonostreptus nigrolabiatus and Gonoplectus malayus has been studied with phase contrast and cytochemical techniques. The process is the same in both species. The Golgi bodies of the early spermatid secrete acrosomal vacuoles which in turn unite to form a large proacrosome. This in turn forms the acrosome. The mitochondria react positively for tryptophan, tyrosine, phospholipides, succinic dehydrogenase and alkaline phosphatase. The Golgi bodies contain carbohydrates (1:2 glycol groups), phospholipids, tyrosine, tryptophan and acid phosphatase. The acrosomal vacuoles, the proacrosome, and the acrosome did not show positive reactions in any of the technique employed, including that of PAS.
    The centriole contains carbohydrates and acid phosphatase; it is PAS positive. The mature sperm is a compressed cell with a piano-convex nucleus.
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  • Syôiti Satô
    1969 Volume 34 Issue 1 Pages 90-92
    Published: March 25, 1969
    Released: March 19, 2009
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  • Tadashi Utakoji
    1969 Volume 34 Issue 1 Pages 93-102
    Published: March 25, 1969
    Released: March 19, 2009
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    Ribonucleic acid synthesis in preimplantation stage embryos of the Syrian hamster was studied cytologically and autoradiographically using whole-mount squash preparations.
    Cytologically, the first cleavage chromosomes were large and extended, and the relational coiling was detected. Pronucleus and the early 2-cell stage nucleus were morphologically similar and contained large amount of heteropycnotic blocks, but no ribonucleoprotein was demonstrated either with May-Grünwald-Giemsa staining or with acridine orange. In the late 2-cell stage, however, the morphology of the nucleus differed considerably from that of pronucleus and of the early 2-cell stage. Several ribonucleoprotein-containing nucleoli appeared in each nucleus, and the rest of nuclear area showed coarse chromatin network with scattered heteropycnotic blocks.
    Chromosomes, which were extended in the first cleavage, became gradually shorter in the course of preimplantation development. In some metaphases in the blastocyst, chromosomes were approximately as compact as those of adult tissues.
    Nucleolar RNA synthesis was demonstrated in the late 2-cell stage. Heavy H3-UR incorporation appeared in the nucleoli of blastomeres from the late 2-cell stage to the blastocyst. Chromatin was also active in RNA synthesis. No grains above the background level were observed in the cytoplasm of metaphase and anaphase cells of these embryos.
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  • S. Bose, U. C. Panigrahi
    1969 Volume 34 Issue 1 Pages 103-111
    Published: March 25, 1969
    Released: March 19, 2009
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    Apical growing regions of two varieties of Z. linearis, Orange and White, were treated with 0.2% colchicine for 12 hours (four hours daily for three days).
    Survival of plants till maturity was less in colchicine treated ones than in the controls. Typical effects of colchicine like slow growth of plants during early stages of development, thicker, leathery and deformed leaves, shorter internode, increased basal circumference and more number of branches were observed in the treated plants in comparison with the control. In addition to this, colchicine treated ones of both the varieties had less number and bigger sizes of stomata in comparison with the control.
    In the colchicine treated plants of the var. White all the buds dried up before the flowers opend while the control plants flowered and had seed formation. Significant increase in pollen size and sterility was observed in the colchicine treated plants of the var. Orange in comparison with the control. Meiotic count of n=12 chromosomes was made from some of the control and colchicine treated plants in the var. Orange while n=24 chromosomes was counted in a few of the colchicine treated ones. Meiotic irregularities like unequal separation of chromosomes at anaphase I were noted in some of the treated ones while control plants were free from these. Irregularities during pollen grain formation were also noted in the colchicine treated ones. Number of fruit (seed) per capitulum was significantly higher in the control plants.
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  • I. The effect of low temperature
    C. B. S. R. Sarma
    1969 Volume 34 Issue 1 Pages 112-117
    Published: March 25, 1969
    Released: March 19, 2009
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    The division patterns round the clock have been determined for the root tips of Ephedra foliata under normal and continuous cold conditions. The mitotic frequency is generally uniform in the normal material whereas the cold grown material shows peaks and falls. 5 mitotic cycles falling into two waves alternated by preparatory periods have been distinguished in the normal material. This pattern was disturbed under low temperature treatment where six mitotic cycles are found and with no definite preparatory period. It was thought that all the variations are due to the effect of the changed environment on the preparatory period, primarily.
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  • C. N. Sun, D. H. Bowden
    1969 Volume 34 Issue 1 Pages 118-125
    Published: March 25, 1969
    Released: March 19, 2009
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    The striated muscle fibers of the heart and of the diaphragm were more severely affected by plasmocid poisoning than were those of the quadriceps. In the three types of muscles, alterations occurred in the mitochondria or myofilaments, but there were significantly quantitative differences. It is concluded that the muscles with the most highly metabolic activity are most susceptible to the toxic effects of the drug.
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  • III. Chromosome behaviour during meiosis in D. bipectinata, D. malerkotliana and their hybrid
    Ravi Dutt Narda
    1969 Volume 34 Issue 1 Pages 126-132
    Published: March 25, 1969
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    The behaviour of chromosomes during meiosis in D. bipectinata, D. malerkotliana and their hybrids has been studied.
    General course of meiosis in D. bipectinata and D. malerkotliana is the same. While leptotene, zygotene and pachytene are not well differentiated, all the other stages of meiosis are normal. Meiosis I is reductional both for the sex chromosomes and the autosomes while meiosis II is equational.
    Meiosis in hybrids follows a more or less normal course except for the occurrence of a few cells showing the suppression of pairing, non-disjunction and lagging chromosomes. A few binucleate spermatocytes have also been observed. The non-motility of the sperms seems to be the main cause of hybrid sterility. The latter probably has its genic basis resulting in the incompatibility of the Y chromosome of one species with the cytoplasm of the other.
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  • II. The sporogenous cells
    Dominick J. Paolillo, Jr
    1969 Volume 34 Issue 1 Pages 133-144
    Published: March 25, 1969
    Released: March 19, 2009
    JOURNAL FREE ACCESS
    As the cells of the archesporium multiply, the plastids flatten and become internally simplified, and no longer contain conspicuous grana. The plastids in the sporocyte round up with the onset of meiosis. The single plastid in each spore is highly simplified and nearly spherical. After the exine of the spore is elaborated, the plastid becomes polymorphic, forms one or more prolamellar bodies and begins to rebuild the grana-fretwork system. Typical chloroplasts are developed before the spores are shed.
    During the early phases of development of the archesporium, its plastids fluoresce a brilliant red in blue light. This chlorophyll fluorescence dims by the time sporocytes are developed, and is virtually undetectable in the newly formed spores. No increase in chlorophyll fluorescence is noted until after the elaboration of the yellow-fluorescing exine. These observations indicate a shut-down in vegetative plastid activities during sporogenesis, and a return to the vegetative state before the spores are shed. The continuity of the plastids through sporogenesis is virtually certain.
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  • I. Differences of mitotic figures between living cells and fixed cells
    Bungo Wada
    1969 Volume 34 Issue 1 Pages 145-159
    Published: March 25, 1969
    Released: March 19, 2009
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  • Juan C. Stockert
    1969 Volume 34 Issue 1 Pages 160-162
    Published: March 25, 1969
    Released: March 19, 2009
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    Le present travail montre la presence de subchromatides dans quelques chromosomes humains, provenant de cultures de leucocytes normaux.
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  • L. V. Olah
    1969 Volume 34 Issue 1 Pages 163-168
    Published: March 25, 1969
    Released: March 19, 2009
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