CYTOLOGIA
Online ISSN : 1348-7019
Print ISSN : 0011-4545
Volume 67, Issue 2
Displaying 1-16 of 16 articles from this issue
  • Arun Kumar, S. Rao Rama, T.S. Rathore
    Article type: Others
    Subject area: Others
    2002 Volume 67 Issue 2 Pages 105-115
    Published: 2002
    Released on J-STAGE: February 28, 2003
    JOURNAL OPEN ACCESS
    Male meiosis in 12 accessions belonging to 2 species of the genus Salvadora viz. S. persica and S. oleoides, an important medicinal and oil-yielding tree has been studied in detail. The somatic chromosome number in both the species is confirmed as 2n=24. Two basic numbers n=12 and 13 are contemplated for the genus. Analysis of chromosome associations revealed regular occurrence of univalents and bivalents. Among bivalents ring type were more in number as compared to rod bivalents, which normally had terminalized chiasma. A single nucleous which always showed affinity towards 1 to 3 bivalents, was the common observation in PMCs. Structural rather than numerical changes (polyploidy) seems to have played a significant role in speciation and evolution of the genus Salvadora.
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  • Anderson Luis Alves, Isabel Cristina Martins-Santos
    Article type: Others
    Subject area: Others
    2002 Volume 67 Issue 2 Pages 117-122
    Published: 2002
    Released on J-STAGE: February 28, 2003
    JOURNAL OPEN ACCESS
    Cytogenetic analysis in 2 populations of Astyanax scabripinnis from São Domingos and Tamboara streams, affluents of the Ivai river basin, was carried out. Both populations presented same diploid of 2n=48 chromosomes, although they might be differentiated by karyotypic formulae (10M, 20SM, 8ST, 10A and 10M, 24SM, 6ST, 8A, respectively) and number of nucleolar organizer chromosomes (3 and 7 NORs, respectively). Besides the population from São Domingos showed 1 metacentric B microchromosome restricted to females. Low frequency of this B microchromosome suggets a recent origin in populations of Astyanax scabripinnis and its adaptive function remains unknown. Aspects related to karyotype diversity of this “species complex” are discussed, contributing to the understanding of the mechanisms involved in the diversity and speciation on the group.
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  • Daniele Aparecida Matoso, Marcelo Ricardo Vicari, Mara Cristina de Alm ...
    Article type: Others
    Subject area: Others
    2002 Volume 67 Issue 2 Pages 123-128
    Published: 2002
    Released on J-STAGE: February 28, 2003
    JOURNAL OPEN ACCESS
    The chromosomes of Astyanax sp. is now described for the first time. Ten specimens of a highly isolated population from the Sinkhole 1 (Vila Velha State Park, Ponta Grossa, PR, Brazil) were analyzed, with the characterization of the karyotype, constitutive heterochromatin and nucleolar organizer regions. Males and females of this species present a similar karyotypic structure (2n=48, 6M+18SM+14ST+10A), without morphologically differentiated sex chromosomes. A great variability concerning the heterochromatin located on the subtelo-acrocentric chromosomes appears also in this species, accordingly to that occur in some other Astyanax species.
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  • M.R. Singh
    Article type: Others
    Subject area: Others
    2002 Volume 67 Issue 2 Pages 129-133
    Published: 2002
    Released on J-STAGE: February 28, 2003
    JOURNAL OPEN ACCESS
    Three induced barley desynaptic mutants DM63, DM92 and DM105 showed varying frequency of univalents and bivalents at MI. The range of univalents per cell was 2-8, 8-14, and 4-8 in these mutants. They exhibited unequal separations and lagging of chromosomes at AI. Multipolar separations and presence of micronuclei in spores were also observed. The mutants were monogenic recessive. ds63 (DM63) was found linked with marker genes V and e in chromosome 2. The recombination values of this gene with marker genes V and e were 40.68±3.74 and 20.71±4.82 respectively. It was mapped in chromosomes 2 in short arm left to marker gene e. Gene ds92 (DM92) was found linked with marker gene trd and B in chromosomes 5 and its recombination values with trd and B were 36.62±3.75 and 24.47±4.17 respectively. This gene was located proximal to B with respect to centromere in long arm of chromosome 1. Gene ds105 (DM105) was found linked with lk2 and n in chromosome 1. The recombination values of this gene with lk2 and n were 36.73±5.41 and 26.78±5.00 respectively. This gene was located in long arm of chromosome 1 in between centromere and marker gene n.
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  • Öztürk Özdemir, Selma Süngü, E.Ferda Percin, ...
    Article type: Others
    Subject area: Others
    2002 Volume 67 Issue 2 Pages 135-137
    Published: 2002
    Released on J-STAGE: February 28, 2003
    JOURNAL OPEN ACCESS
    We report 2 cases of complete androgen insensitivity syndrome from 1 family with 45, XY, t(13q; 14q) karyotype including complete testicular feminisation (TF) clinical features. The chromosomal translocation is not generally considered part of the clinic spectrum in this group patients and most possibly it is the first report in the literature.
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  • Öztürk Özdemir, Hüseyin Eray Bulut, Mehmet Korkmaz ...
    Article type: Others
    Subject area: Others
    2002 Volume 67 Issue 2 Pages 139-144
    Published: 2002
    Released on J-STAGE: February 28, 2003
    JOURNAL OPEN ACCESS
    N-ethyl-N-nitrosourea (ENU) is a potential carcinogenic agent commonly used in industry, and it may cause an uncontrollable cell proliferation and eventually tumourgenesis. On the other hand, the hypomethilation of DNA by 5-aza-2′-deoxycytidine is the best known anti-tumoural mechanism used for the treatment of leukemia. Therefore the present study aimed to find out the possible healing effects of 5-aza-2′-deoxycytidine on lymphocyte hyperproliferation in the rat colon through the above mentioned DNA hypomethylation mechanism. Rats were injected with 300 mg/kg body weight ENU (i.p.) in order to induce tumour development. Following 45 weeks when the tumourgenesis was proved visually, animals were treated with 5-aza-2′-deoxycytidine 100 μg/100 g body weight twice a week intraperitoneally for 15 weeks. After the experimental procedure, all animals were sacrificed and colonal tissues were obtained. Tissues were processed for light and electron microscopy. While no colonal tumour development was observed in the control group, an extensive tumour development was seen in the subcutaneous region in the high dose ENU treated group. The light and electron microscopical examination of the rat colonal tissue revealed a lymphocyte hyperproliferation and invasion in the submucosal region, an increased number of polimorphonuclear leukocytes (PMNLs) and occasional epithelial lesions. On the other hand, the evaluation of the 5-aza-2′-deoxycytidine treatment group rat colon demonstrated features similar to those seen in the control and PEG treated groups indicating a possible anti-neoplastic effect of 5-aza-2′-deoxycytidine via DNA hypomethylation.
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  • Carminda da Cruz-Landim, Rodrigo Pires Dallacqua
    Article type: Others
    Subject area: Others
    2002 Volume 67 Issue 2 Pages 145-151
    Published: 2002
    Released on J-STAGE: February 28, 2003
    JOURNAL OPEN ACCESS
    The present paper reports morphological features of the testes reabsorption in adult male of Melipona bicolor bicolor. The ultrastructural features of the degenerating sperm cells and cyst cells are described. It is suggested that the material of the reabsorbed testes may serve as nutritional source for the adult male.
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  • Lale Dönbak, Eyyüp Rencüzogullari, Mehmet Topaktas
    Article type: Others
    Subject area: Others
    2002 Volume 67 Issue 2 Pages 153-157
    Published: 2002
    Released on J-STAGE: February 28, 2003
    JOURNAL OPEN ACCESS
    In this study, the cytogenetic effects of boric acid (BA) were investigated in root tip cells of Allium cepa L. The roots of A. cepa were treated with the concentration of 1 g/l, 2 g/l and 4 g/l of BA for 10 and 20 h treatment pariods. BA significantly decreased the mitotic index (MI) compared to the control at all concentrations and treatment periods. However, the decreasing of the MI was not dose-dependent. BA slightly increased the percentage of abnormal cells.
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  • D.H. Jacobs, H.T. Groeneveld
    Article type: Others
    Subject area: Others
    2002 Volume 67 Issue 2 Pages 159-168
    Published: 2002
    Released on J-STAGE: February 28, 2003
    JOURNAL OPEN ACCESS
    The meiosis and karyotypes of the 3 Silvacoris species are described, figured and discussed. S. heissi Jacobs and S. pondolandensis Jacobs have 2n=14XY while S. karkloofensis Jacobs has 2n=12XY with 1 autosome distinctly larger than the others. A statistical method(based on the bootstrap method of Efron) to test the hypothesis that 2 autosomes of the S. heissi karyotype fused to form the large chromosome of S. karkloofensis is described and performed. It is concluded that autosomes 1 and 5 of the S. heissi karyotype most probably fused to form the large chromosome of S. karkloofensis.
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  • Karina Sayuri Utsunomiya, Nilton Cesar Pires Bione, Maria Suely Paglia ...
    Article type: Others
    Subject area: Others
    2002 Volume 67 Issue 2 Pages 169-176
    Published: 2002
    Released on J-STAGE: February 28, 2003
    JOURNAL OPEN ACCESS
    Verification of the different kinds of meiotic abnormalities in a unique endogamous maize plant was undertaken by analyzing 53324 cells, including meiocytes and meiotic products, scored among 433 male flowers. A total of 6456 cells (12.11%) were affected by certain kind of meiotic abnormality that could impair, in different ways, pollen viability. Abnormalities were related to chromosome segregation, absence of cytokinesis, cytomixis, cell fusion, irregular cell shape, chromosome bridges, and genomic separation. Abnormalities compromised meiotic products and a high frequency of abnormal microspores was produced. High frequency of different kinds of meiotic abnormalities in a unique plant may be explained by gene segregation for meiosis control during selfing. The influence of meiotic abnormalities in the combining ability of inbred lines is discussed.
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  • Nilton Cesar Pires Bione, Maria Suely Pagliarini, Leones Alves de Alme ...
    Article type: Others
    Subject area: Others
    2002 Volume 67 Issue 2 Pages 177-183
    Published: 2002
    Released on J-STAGE: February 28, 2003
    JOURNAL OPEN ACCESS
    A mutation affecting microsporogenesis and causing complete male sterility has been detected in line BR97-13777H from Embrapa National Soybean Research Center breeding program. In prophase I, the meiotic behavior of this mutant was similar to the synaptic mutants previously reported in soybeans. Many univalents and few bivalents were found in diakinesis. The main and distinctive characteristic of this mutant was the complete inability of univalents to congregate in the metaphase plate. Scattered in the cytoplasm, univalents underwent premature sister chromatid separation, so that 80 chromatids could be easily counted. Telophases II with a varied number of different-sized nuclei were observed. Pollen sterility was estimated at 93.12%. The inability of univalents to congregate at the equator made us classify it as asynaptic mutant. Its special characteristic related to precocious sister chromatids separation suggests that it is probably defective in proteins that promote sister chromatid cohesion. Segregation ratio for male sterility was 3:1 and shows that mutation, similar to other synaptic mutations previously reported in soybean, is associated with the homozygous condition of a single recessive gene. Allele tests with the st series of synaptic mutants are in progress.
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  • V. Sridevi, K. Devi Uma, S. Sivaramakrishnan, N.R. Isola
    Article type: Others
    Subject area: Others
    2002 Volume 67 Issue 2 Pages 185-190
    Published: 2002
    Released on J-STAGE: February 28, 2003
    JOURNAL OPEN ACCESS
    The intolerance exhibited to loss of DNA end sequences beyond a threshold, points to the existence of a requirement of a minimum telomere size per chromosome end. The relation of chromosome length to telomere length was studied in the genus Pennisetum. Species differing in chromosome length were analysed for telomere length. For a relative comparison, the extent of intra specific variation in telomere length was studied in the cultivated species of Pennisetum-P. glaucum (L.) R. Br. (pearl millet) using 8 inbred lines. Average telomere length (ATL) was estimated by densitometric measurement of the hybridization signal in the autoradiograms made from Southern blots of Hae III digested DNA samples probed with the plant telomere repeat sequence (5′-TTTAGGG-3′)4. The significance of the differences in ATL values in the plants analysed was determined by ANOVA and ‘t’ test. P. orientale, the species with very short chromosomes also had very short telomeres (ATL ca. 10kb). The ATL in the other species with much longer chromosomes than P. orientale was much higher-ranging between ca. 17 to ca. 24kb. Significant differences in ATL were observed among the inbreds of P. glaucum. One of the P. glaucum inbreds had a very high ATL value of ca. 41kb. The wild species with small differences in chromosome length did not have a significant difference in ATL values.
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  • G. Venkatachalaiah, G. Venu
    Article type: Others
    Subject area: Others
    2002 Volume 67 Issue 2 Pages 191-198
    Published: 2002
    Released on J-STAGE: February 28, 2003
    JOURNAL OPEN ACCESS
    Three species of Caecilians, namely I. beddomei, I. ssp. and I. malabarensis were collected from different places of Karnataka and Kerala. Mitotic and meiotic chromosomes were prepared from liver and testis respectively. The karyotypes of 3 species i.e. I. beddomei (2n=42), I. ssp. (2n=42) and I. malabarensis (2n=36) are prepared and compared. A probable role of chromosomal rearrangements involved in the evolution of karyotypes of these 3 species is surmised in this paper.
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  • Luciana Andreia Borin, Isabel Cristina Martins-Santos
    Article type: Others
    Subject area: Others
    2002 Volume 67 Issue 2 Pages 199-204
    Published: 2002
    Released on J-STAGE: February 28, 2003
    JOURNAL OPEN ACCESS
    Cytogenetic studies of genus Pimelodus (P. maculatus, P. ornatus, P. absconditus) occurring in the River Paraná were carried out. The 3 species analyzed resulted in the number 2n=56 chromosomes with differences in the formulae karyotypic. The nucleolus organizer regions (NORs) showed heterochromatic and CMA3+in the 3 species studied. In P. maculatus and P. absconditus this region was localized in terminal position on the long arm of a subtelocentric chromosome pair, while in P. ornatus the region lies on the short arm of a subtelocentric pair. Analysis of C-band pattern showed blocks located in centromeric and telomeric position in the 3 species and interstitial in P. maculatus and P. absconditus. Karyotypical comparisons with regard constitutive heterochromatin and NOR banding demonstrated a greater similarity between the 2 species.
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  • Rubén Darío Almada, Guillermo Seijo, Julio Daviña
    Article type: Others
    Subject area: Others
    2002 Volume 67 Issue 2 Pages 205-211
    Published: 2002
    Released on J-STAGE: February 28, 2003
    JOURNAL OPEN ACCESS
    In this study, mitotic and meiotic counts are informed for 10 species that belong to 5 out of the 7 sections represented in Argentina. The chromosome numbers of E. coronatum (n=8) and E. pristis (2n=16) constitute the first counts for the species, chromosome numbers that differ from previous counts are given for some species, and counts for other taxa are confirmed. Furthermore, the karyotype analysis of E. ebracteatum is provided, which is the first description for the New World species. Chromosome analysis showed that E. pristis, E. ekmanii, E. ebracteatum, E. elegans, E. coronatum and E. floribundum are diploids and E. pandanifolium is octoploid with x=8, while E. horridum and E. mudicaule are diploids with x=7. These data demonstrate that the genus is at least dibasic and it is proposed that variation in basic chromosome number may have occurred by dysploid change. Chromosome counts showed that most of the analysed species are diploids, except in section Panniculata, which has a relatively high percentage of polyploid species. Therefore, dysploidy an polyploidy are both mechanism that may have been involved in chromosome number changes during the evolution of Eryngium species.
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  • Richa Srivastava, G.K. Srivastava
    Article type: Others
    Subject area: Others
    2002 Volume 67 Issue 2 Pages 213-220
    Published: 2002
    Released on J-STAGE: February 28, 2003
    JOURNAL OPEN ACCESS
    Autopolyploid plants of Helianthus annuus var. morden were obtained by treating seedlings (2-5 d old) with 0.4%, 0.5% and 0.6% colchicine for 12 h. The autopolyploids exhibited reduction in the height, girth, leaves and flowers of the plants but increase in the size of stomata, pollen grains and meiocytes. Pollen and seed fertility were reduced. There was increase in seed weight from diploids to C1 and then to C2 generations in tetraploids, but increase in C1 and decrease in C2 generation in octoploids. Low seed setting in C1 generation which, however improved in C2 generation only in tetraploids. C2 generation was absent in hexa-decaploids. The chromosome number in diploids, tetraploids, octoploids and hexa-decaploids were found to be 2n=34, 68, 136 and 272, respectively. Meiotic observations showed various associations of chromosomes such as univalents, bivalents and quadrivalents and abnormalities such as laggards, unequal separation of chromosomes, bridges, stickiness in C1 generation which lessened in C2 generation in tetraploids but increase in octoploids. These irregularties appeared to be the major factors responsible for high pollen sterility in autopolyploids. High or number of bivalents and lower frequency of abnormalities at metaphase in tetraploids in C2 generation led to an improvement in pollen and plant fertility.
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