CYTOLOGIA
Online ISSN : 1348-7019
Print ISSN : 0011-4545
Volume 66 , Issue 3
Showing 1-16 articles out of 16 articles from the selected issue
  • R. Sudhakar, K. N. Ninge Gowda, G. Venu
    2001 Volume 66 Issue 3 Pages 235-239
    Published: September 25, 2001
    Released: November 09, 2009
    JOURNAL FREE ACCESS
    The silk dyeing industry effluents were examined for the induction of mitotic abnormalities in Allium cepa root system. Cytotoxicity of the effluent was studied by treating Allium cepa roots with different concentrations of effluent (25, 50, 75, 100%) for different durations (6, 12, 24, 48 h) along with control. The effluent inhibited cell division and a strong dosage effect was obvious from a decline in the mitotic index with the increase in effluent concentration and duration of treatment. The effluent also induced a wide range of mitotic abnormalities. The abnormalities observed included stickiness of chromosomes, fragments, bridges, laggards, binucleate cells and vacuolated nuclei. The results showed that silk dyeing industry effluents act as potential mutagens.
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  • G. A. Malallah, T. A. Attia, M. Masood
    2001 Volume 66 Issue 3 Pages 241-246
    Published: September 25, 2001
    Released: November 09, 2009
    JOURNAL FREE ACCESS
    A cytological study of wild Picris babylonica in Kuwait revealed several aneuploids; monosomic (2n =9), trisomic (2n =11) and tetrasomic (2n =12) in addition to the prevailing euploidy condition (2n =10). Morphological features were not appreciably different among the aneuploid plants. Karyotype analyses showed that the first chromosome pair was probably involved either in trisomic or monosomic plants. Two univalents plus 4 bivalents were also detected in some analyzed PMC's. The possible origion of aneuploids and their probable relevance in speciation and evolution in plants are discussed.
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  • S. Kumar, H. S. Balyan, B. Ramesh, S. P. Singh, P. K. Gupta
    2001 Volume 66 Issue 3 Pages 247-252
    Published: September 25, 2001
    Released: November 09, 2009
    JOURNAL FREE ACCESS
    The number of nucleolar organizing chromosomes in lentil (Lens culinaris Medik.) was ascertained using classical and molecular cytogenetic approaches, since in an earlier report, only one pair of nucleolar organizing chromosomes was resolved by FISH, although 1-3 nucleolar organizing chromosomes were reported in literature. During the present study, data on the number of nucleoli per cell in the normal lentil material (cv. PL639) was recorded at diakinesis and spore quartet stages of meiosis, and the number of bivalents associated with nucleoli were recorded at diakinesis. Use of a ribosomal DNA probe (pTa71) for FISH revealed only one pair of nucleolar organizing chromosomes on mitotic metaphase chromosomes (as also reported in an earlier study), but at spore quartet stage, 2 signals were observed in a spore (presumably due to decondensed state of chromosomes), suggesting the presence of 2 nucleolar organizing chromosomes. An interchange heterozygote, which had a nucleolar organizing chromosome involved in the interchange, was also used in this study; although at mitotic metaphase, only one pair of nucleolar organizing chromosomes was resolved by FISH, at spore quartet stage, frequencies of nucleoli per spore suggested the presence of 2 nucleolar organizing chromosomes. Taken together the results suggested that in the lentil material used in the present study, there are at least 2 pairs of nucleolar organizing chromosomes.
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  • Ricardo A. Lombello, Eliana R. Forni-Martins
    2001 Volume 66 Issue 3 Pages 253-259
    Published: September 25, 2001
    Released: November 09, 2009
    JOURNAL FREE ACCESS
    Cytological studies were carried out on 6 species of Banisteriopsis and 4 species of Heteropterys (Malpighiaceae, Malpighioideae), collected in forest and cerrado areas of southeastern Brazil, and a cultivated one. No previous chromosome counts are known for 3 species of Banisteriopsis and 3 species of Heteropterys. Chromosome numbers were obtained through mitotic (7 counts) and meiotic (5 counts) analysis. No meiotic abnormalities were encountered in the species studied, which presented high viable pollen rates. For the first time, karyomorphological characters were found for both genera, with a predominance of metacentric chromosomes. The chromosome number variation, based on x=5 and 10, with cases of polyploidy, and the similarity between the 2 related genera are discussed.
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  • A. M. Palermo, M. R. Ferrari, C. A. Naranjo
    2001 Volume 66 Issue 3 Pages 261-267
    Published: September 25, 2001
    Released: November 09, 2009
    JOURNAL FREE ACCESS
    Male meiosis of 3 South American species of the genus Vicia (V graminea Sm., V. macrograminea Burk., V. epetiolaris Burk.) was studied. The early meiotic prophase I was characterized by a “bouquet stage” or synizesis. All 3 species showed regular pairing with 7 bivalents per cell at diakinesis and metaphase I. V. macrograminea and V. epetiolaris presented similar meiotic configurations at both stages, with higher values of total chiasmata per cell and a lower proportion of terminal chiasmata. V. graminea was significantly different in chiasmata behaviour since the populations studied presented lower chiasma frequency and distal localization. The number of ring bivalents per cell in metaphase I was lower in V. graminea but not significant.
    The distribution of chromosomes to the poles in anaphase I as well as the course of the second meiotic division were regular in all 3 species, though bridges without fragments were occasionally observed in anaphase I. These side-arm bridges generally resolve successfully, since the fertility is high (>90%) in all cases. The occurrence of these bridges in species of Vicia from the north hemisphere and in the South American species studied, suggests that non-disjunction could have play a role in the evolution of the basic number of the genus, where the earliest basic number is regarded as x=7, from which x=6 and x=5 arose.
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  • Armando Garcia-Velazquez
    2001 Volume 66 Issue 3 Pages 269-274
    Published: September 25, 2001
    Released: November 09, 2009
    JOURNAL FREE ACCESS
    Two desynaptic plants causing dissociation of pairing chromosomes were found among plants collected in wild populations of Rhoeo spathacea. One of those plants is of the spathacea variety and was identified as GAVA YT-1, while the other was found to be of the concolor variety and was identified as GAVA C-2. Both plants were found to be diploids with 2n=12 and displayed 2 cytotypes : 9m +3sm and 4m +8sm, respectively. GAVA C-2 is the first desynaptic plant observed of the concolor variety. The mutant plants formed univalents in all PMC at MI. GAVA YT-1 formed 12 univalents in 84.9% of PMC and 89.7% in PMC of GAVA C-2. Microspores from GAVA YT-1 had chromosome from n=5 to n=12, and microspores produced by GAVA C-2 showed n=8 to n=18. The GAVA C-2 plant produced 21.3% unreduced microspores. There were large differences in pollen stainability between the 2 desynaptics : GAVA YT-1 with 17.2% and GAVA C-2 with 55.5%.
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  • Ana Cláudia Swarça, Lúcia Giuliano-Caetano, Andr& ...
    2001 Volume 66 Issue 3 Pages 275-278
    Published: September 25, 2001
    Released: November 09, 2009
    JOURNAL FREE ACCESS
    The ribosomal RNA genes of Pinirampus pirinampu have been localized by fluorescence in situ Hybridization hybridization (FISH) with 18S rDNA probe. This method allowed the location of FITC signals on the short arm of the biggest subtelocentric chromossomic pair and evidenced a size heteromorphism of hybridization signals between homologous chromosomes. This difference has been attributed to variation in the amount of rRNA genes per cluster, probably due structural modifications (i.e. duplications by unequal crossing over or transpositions) of NOR involving homologous segments.
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  • Patricia Martins Casseb-Hassan, Maria Tercilia Vilela De Azeredo-Olive ...
    2001 Volume 66 Issue 3 Pages 279-285
    Published: September 25, 2001
    Released: November 09, 2009
    JOURNAL FREE ACCESS
    The effect of environmental temperature on insects is observed in different physiological processes. The aim of the present study was to analyze the nuclei of cells in Malpighian tubules in triatomines of the species Rhodnius prolixus, submitted to temperature alterations such as hypothermic and hyperthemic shock. Male and female adult insects, were exposed to temperatures between-4°C and 40°C, in time intervals corresponding to 1, 6 and 12 h. Later on, the Malpighian tubules were removed and deposited over the slide and after submitted to squashing they underwent the impregnation technique by means of silver nitrate which stained the nucleolar corpuscle. In males, the fusion of nucleolar corpuscles was observed in both temperatures, more markedly in the 12 h period. In females, however, at-4°C total fusion of such corpuscles was observed in some nuclei while it was only partial in others. During hypothermic shock the nucleolar corpuscles presented differential impregnation by silver and the presence of polyploid nucleus was more often found. It is suggested that the observed alterations may be due to metabolic nuclear organisms that lead to a variation in transcriptional activity in response to such situation of physiological stress.
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  • Andréa Beatriz Mendes-Bonato, Maria Suely Pagliarini, Cacilda B ...
    2001 Volume 66 Issue 3 Pages 287-291
    Published: September 25, 2001
    Released: November 09, 2009
    JOURNAL FREE ACCESS
    Among 25 accessions of Brachiaria brizantha in the Embrapa Beef Cattle collection, one accession (GC 1113/95) presented a severe case of chromosome stickiness in meiosis, impairing normal chromosome segregation. Accession was tetraploid (2n =4x=36) with chromosomes pairing in bivalents and few quadrivalents at diakinesis. Stages of prophase I were normal and chromosome stickiness became evident from metaphase I persisting to microspore stage. Bridges of different thickness were formed in anaphase I and II by chromosomes that did not separate. Some of them even persisted until telophase stages. The precise causes of chromosome stickiness could not be ascertained, but genetic factors might be controlling the phenomenon, since only this accession cultivated on Brazilian savannas under the same environmental conditions of the 24 other accessions presented the abnormality.
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  • G. I. Lavia, A. Fernández, C. E. Simpson, G. Seijo
    2001 Volume 66 Issue 3 Pages 293-298
    Published: September 25, 2001
    Released: February 22, 2010
    JOURNAL FREE ACCESS
    Meiotic behaviour of A. lignosa, A. rigonii (Sect. Procumbentes), A. microsperma, A. simpsonii and A. williamsii (Sect. Arachis) is reported for the first time, and for A. batizocoi, A. stenosperma and A. villosa were studied in different accessions than the previously reported ones. All the species analyzed were diploid forming 10 II at diakinesis-metaphase I, except A. stenosperma which presented 8 II+ 1 IV in 3% of the pollen mother cells. Most of the bivalents were of the ring type, and only 1 or 2 bivalents were usually of the rod type. Chiasmata were always located in distal to terminal position even at diplotene and diakinesis. Normal segregation of bivalents was observed which is in accordance with the recorded high pollen stainability. Only 1 pair of chromosomes was easily recognized, that being the very small “A” pair in the A genome of Arachis section species. This small pair can be used also at meiosis to distinguish the A and B genomes. Key words Arachis;Meiosis;A and B genomes.
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  • Miriam Abucarma, Isabel Cristina Martins-Santos
    2001 Volume 66 Issue 3 Pages 299-306
    Published: September 25, 2001
    Released: November 09, 2009
    JOURNAL FREE ACCESS
    Cytogenetic studies of species of Rhamdia branneri, R. voulezi and Rhamdia sp., endemic of the River Iguacu basin, were carried out. Karyotypic analysis resulted in diploid number of 2n =58 for the 3 species. A variation between 58 to 62 chromosomes was observed in Rhamdia branneri, while in Rhamdia voulezi and Rhamdia sp. the number of chromosomes ranged from 58 to 60. These variations were attributed to the presence of B chromosomes. Although the diploid number and karyotypic formulae were similar, differences in number and type of B chromosomes were observed. While in R. branneri and R. voulezi were found metacentric B chromosomes, in Rhamdia sp. was observed an acrocentric B microchromosome. A submetacentric B chromosome found in R. branneri, was also considered as species-specific marker. The results from C banding analysis and chromomycin A3 showed that in R. branneri the metacentric B chromosome was heterochromatic partially and CMA+3 in telomeric regions, while those in R. voulezi and Rhamdia sp. (metacentric and acrocentric, respectively) were euchromatic and CMA-3. The submetacentric B chromosome of R. branneri showed C+ band and CMA-3 in subterminal region of the long arm. These differences may be considered as a cytotaxonomical characteristic. Silver differential coloration also showed differences : R. voulezi had simple NOR and R. branneri and Rhamdia sp. had a system of multiple NOR.
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  • Masahiro Hizume, Teiji Kondo, Fukashi Shibata, Ryoko Ishizuka
    2001 Volume 66 Issue 3 Pages 307-311
    Published: September 25, 2001
    Released: November 09, 2009
    JOURNAL FREE ACCESS
    The genome sizes of 13 species of Taxodiaceae, 19 species of Cupressaceae s.s. and Sciadopitys verticillata were determined by flow cytometry of isolated nuclei stained with propidium iodide, using Hordeum vulgare nuclei as an internal standard. In Taxodiaceae, the genomes of Cunninghamia lanceolata (28.34 pg/2C) and Taiwania species (25.78, 26.80 pg/2C) were larger than those of other genera/species, which ranged from 19.85 to 22.87 pg/2C. In Cupressaceae s.s., genome size ranged from 20.03 to 27.93 pg/2C among 16 species. The Calocedrus species and Thujopsis had a larger genome than most other species. Sciadopitys verticillata had a large genome of 41.60 pg/2C. After comparing the diversity in genome size with previously reported cladograms constructed using nucleotide sequence data, the tendency of changes in genome size with phylogenetic differentiation is discussed.
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  • Girlene de Cássia Bez, Berenice Quinzani Jordão, Veronic ...
    2001 Volume 66 Issue 3 Pages 313-318
    Published: September 25, 2001
    Released: February 22, 2010
    JOURNAL FREE ACCESS
    Chlorophyll and its derivatives are an example of vegetable compounds with protective action against DNA damage caused by chemical and physical agents. This study was carried out to assess the clastogenic and anticlastogenic action of chlorophyll-a (Chl-a) and chlorophyll-b (Chl-b) on chromosome aberration induction by the mitomycin-C in lymphocyte cultures from human peripheral blood. Six young healthy individuals were used in the experimental protocol, and a negative control, positive control with mitomycin-C (MMC), solvent control with 0.0025% ethanol (SC), treatments with Chl-a and Chl-b at concentration in culture medium of 0.25 μg/ml and chlorophyll treatments associated with MMC (0.03 μg/ml of culture medium) were prepared for each individual. The total culture time was 72 h. The SC, Chl-a and Chl-b treatments were carried out at the beginning of the culture and the MMC treatment was 48 h after the start of culture. One hundred metaphases were analyzed in each culture. The treatments with Chl-a and Chl-b were not clastogenic. Chlorophyll associated with the aberration inducing agent (MMC) showed a protective effect against DNA damage due to the decrease in the number of cells with breaks (Chl-a reduction=64.6%, Chl-b reduction=56.9%). There was reduction mainly in the isochromatid type breaks (Chl-a reduction=82.7%, Chl-b reduction=79.3%) compared to the chromatid type (Chl-a reduction=55.8%, Chl-b reduction=44.2%). The anticlastogenic data obtained suggest that the molecule types used acted similarly with the same efficacy, mainly in the phases G1 and S of cell cycle, where chromosome breaks commonly occur.
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  • 2. Chromosome Variation of Trillium undulatum in North America
    Ichiro Fukuda
    2001 Volume 66 Issue 3 Pages 319-327
    Published: September 25, 2001
    Released: November 09, 2009
    JOURNAL FREE ACCESS
    Chromosome analysis by the cold-induced heterochromatin banding method was carried out for populations of the American species Trillium undulatum. The banded karyotypes of individuals within the species were polymorphic. Furthermore, a comparative study showed that the genome of T. undulatum has a close relationship with the G genome of the Asian species T. govanianum. It is an interesting evolutionarily problem to speculate on how the American and Asian species of Trillium species connected in both continents across the Pacific Ocean.
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  • Mercival Roberto Francisco, Vitor De Oliveira Lunardi, Pedro Manoel Ga ...
    2001 Volume 66 Issue 3 Pages 329-332
    Published: September 25, 2001
    Released: November 09, 2009
    JOURNAL FREE ACCESS
    Behavioral and morphological characters, as well as DNA hybridization and sequencing data strongly suggests that New and Old World Psittacidae evolved independently, supporting the tribe status for the American species (Arini). However, species and genera relationships within this group remain poorly known, and convergence was detected in various morphological characters, which could lead to artificial classifications. Most authors have subdivided Arini tribe in 2 monophyletic groups based on the comparative length of the tail, what is still controversial. In this paper we are describing for the first time the karyotypes of Pionites leucogaster and Pionopsitta pileata, both short-tail species which presented the same karyotypical pattern only previously observed to the long-tail genera. The remarkable karyotypical dichotomy presented by the Neotropical Psittacidae emphasize the existence of 2 distinct monophyletic groups within the Arini tribe. Nevertheless, the karyotypes of P. leucogaster and P. pileata short-tail species, suggests that the generalization long and short-tail is not valid to represent these both monophyletical groups, and there could occurs convergence in tail morphology character.
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  • José A. Lisanti, Elsa Pinna Senn, María-Isabel Ortiz, Gr ...
    2001 Volume 66 Issue 3 Pages 333-339
    Published: September 25, 2001
    Released: November 09, 2009
    JOURNAL FREE ACCESS
    Akodon is the richest Sigmodontine genus in terms of number of species. This article analyzes the chromosomal banding produced in A. azarae, A. molinae and A. dolores by the fluorochromes 4, 6-diamidino-2-phenylindole (DAPI) and chromomycin A3 (CMA), counterstained in some cases with distamycin A (DA). A. azarae populations have fertile XY females, and A. molinae and A. dolores, a pair of closely related species, show Robertsonian polymorphisms. In the 3 species, as generally observed in mammals, DAPI-treated chromosomes presented a G/Q-like fluorescent pattern, and DA-CMA treatment gave R-type banding. The constitutive heterochromatin of A. azarae, comprising the centric regions of the autosomes (excepting the small metacentric), the Ychromosome, and several bands of the X amounting to almost 38% of its length, fluoresced with DAPI and appeared negative with DA-CMA, indicating the relative AT-richness of their repetitive components. In A. molinae and A. dolores, no characteristic fluorescence was noticed in the small heterochromatic regions of the autosomes. The heterochromatic Y of these species could be differentiated into a centric portion (approximately one third of the chromosome) that fluoresced with DACMA, and was therefore relatively GC-rich, and a distal portion that fluoresced brightly with DAPI, which was thus relatively AT-rich; the small centric band of the X fluoresced with CMA. The response of the gonosomal centric regions indicates that these chromosomes associate by their centromeric ends in diakinesis-metaphase I. These observations confirm the utility of fluorochromes that are highly selective for DNA base pair composition in cytogenetic studies, and further our understanding of the chromosomal evolution in this genus.
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