Showing papers in "Cytologia in 1991"
TL;DR: The result showed that there is a close correlations between nuclear chromosome number or ploids and DNA content in fish, and suggest that the more specialized or evolutionarily advanced species, the less nuclear DNA content the fishes possess.
Abstract: Forty-two species of Chinese freshwater fishes were examined for their cellular DNA content. The result showed that there is a close correlations between nuclear chromosome number or ploids and DNA content in fish. These observations suggest that the more specialized or evolutionarily advanced species, the less nuclear DNA content the fishes possess. The polyploid evolution, the systematic relationship of the fishes and the variations within species are discussed.
47 citations
45 citations
TL;DR: Karyotypes from five species of the genus Vernonia were studied utilizing root tip mitotic metaphases to suggest that in Vernonia there is an evolutionary trend towards formation of aneuploid series and polyploidy.
Abstract: Karyotypes from five species of the genus Vernonia were studied utilizing root tip mitotic metaphases. Vernonia nudiflora and V. polyanthes were tetraploid with 2n=34 (X=17); V. flexuosa and V. simplex were tetraploid with 2n=40 (X=10). V. polyphylla with 2n=64 may be an allotetraploid with X=16 or an autoplolyploid with X=8, that became fertile by diploidization. The basic chromosome numbers are a series of X=7, 8, 9, 10, 15, 16, 17 and 19. We suggest that in Vernonia there is an evolutionary trend towards formation of aneuploid series and polyploidy.
40 citations
TL;DR: It is concluded that P. calcaratus and P. angularis should be grouped in Vigna group (not in Phaseolus nor Azukia) as proposed by Verdcourt (1970).
Abstract: Karyotypes and C-banding patterns of Phaseolus calcaratus, P. angularis, P. coccineus, P. vulgaris, Vigna sesquipedalis and V. sinensis were studied. Chromosome numbers of all species were counted to be 2n=22, and the karyotypic characteristics, such as total chromosome length, S%, F% and TF% values and C-heterochromatin content (%) were also described. The C-banding patterns of P. calcaratus, P. angularis and V. sesquipedalis are reported here for the first time.Based on the results of karyotype formula and C-banding pattern analyses, the six species were grouped into two groups. P. calcaratus, P. angularis, V. sesquipedalis and V. sinensis (group I) that had the same or similar karyotype formulae had centromeric bands on all the chromosomes. On the other hand, P. coccineus and P. vulgaris (group II) that had similar karyotype formulae lacked centromeric bands on some of the chromosomes but had large heterochromatic blocks on the short arms of some chromosomes. We concluded that P. calcaratus and P. angularis should be grouped in Vigna group (not in Phaseolus nor Azukia) as proposed by Verdcourt (1970).
35 citations
TL;DR: The cytology, reproductive behavior and fertility of seven different Paspalum species were studied to determine how they might be used in an interspecific hybridization program and indicated sexual reproduction in P. bertonii and P. ramboi.
Abstract: The cytology, reproductive behavior and fertility of seven different Paspalum species were studied to determine how they might be used in an interspecific hybridization program. Paspalum palustre Mez and P. bertonii Hack. were diploids with 2n=2x=20 chromosomes. Paspalum dedeccae Quarin; P. denticulatum Trin., and one P. distichum L. accession were tetraploids with 2n=4x=40 chromosomes. Another P. distichum accession, P. inaequivalve Raddi, and P. ramboi Barreto were hexaploids with 60 chromosomes. Meiosis was regular with primarily bivalent pairing in P. palustre, P. bertonii, tetraploid P. distichum, P. inaequivalve and P. ramboi. Paspalum dedeccae, two P. denticulatum accessions, and hexaploid P. distichum were meiotically irregular with univalent, bivalent and multivalent (primarily quadrivalent) associations at metaphase I. Megasporogenesis and embryo sac development in P. palustre, P. bertonii, and P. inaequivalve indicated sexual reproduction. Paspalum palustre and P. bertonii were self-incompatible and did not produce self-pollinated seed but P. inaequivalve was self-compatible. Paspalum dedeccae, P. denticulatum, P. distichum, and P. ramboi all reproduced by aposporous apomixis.
32 citations
27 citations
TL;DR: Administration of vitamin C, either concurrently or as pre- and post-treatment to the pesticide exposure, was very much helpful in minimising mitoinhibition and clastogeny induced by two organophosphorus pesticides, Malathion and Rogor.
Abstract: Administration of vitamin C, either concurrently or as pre-and post-treatment to the pesticide exposure, was very much helpful in minimising mitoinhibition and clastogeny induced by two organophosphorus pesticides, Malathion and Rogor. The concurrent treatment with vitamin C was more effective than the two other modes of its supplementation.
25 citations
24 citations
TL;DR: The cytological effects on the pollen mother cells of Lathyrus sativus grown after seed treatment with different concentrations of two pesticides (rogor and bavistin) and an antibiotic (streptomycin) indicated that all the three chemicals were capable of inducing cytological disturbances.
Abstract: The cytological effects on the pollen mother cells of Lathyrus sativus grown after seed treatment with different concentrations of two pesticides (rogor and bavistin) and an antibiotic (streptomycin) indicated that all the three chemicals were capable of inducing cytological disturbances. The dominant types of aberrations included: stickiness, univalents and multivalents, laggards, fragments and bridges. Besides these, some cases of cytomixis were also recorded. Streptomycin proved to be more efficaceous followed by rogor and bavistin. Thus, the genotoxic effect of these chemicals is established.
22 citations
TL;DR: Following EMS, DES and gamma ray treatment in Arkel and Bonneville pea varieties, three male sterile mutants were induced in Pisum sativum and male sterility in all the three mutants is complete while female fertility is normal.
Abstract: Following EMS, DES and gamma ray treatment in Arkel and Bonneville pea varieties, three male sterile mutants were induced in Pisum sativum. Sterility in each of these is conditioned by single recessive genes, the three genes being non-allelic. Whereas in one mutant, the ms gene acts during pre-meiosis, in the other two the genes act during post-meiosis. In the premeiotic mutant, the PMCs either degenerate before attaining genetic autonomy or after separating out from one another. Their chromatin either compacts or fragments to degenerate completely. Thus, no meiosis occurs in this mutant.In both the post-meiotic mutants, male meiosis is normal. In one, the microspores are released from the PMCs either in free or in adhered state. They develop thick walls, their chromatin condenses centrally and finally they degenerate. In the other mutant, monads are released from the PMCs. In 93% microspoes, the nuclear degeneration is faster than cytoplasmic degeneration, in 7% the reverse occurs. In both the post-meiotic mutants, microspores degenerate fully. Male sterility in all the three mutants is complete while female fertility is normal.
20 citations
TL;DR: This study indicated the possibility of a close relationships, but failed in elucidating an origin for R. × hiraseanus.
Abstract: Three taxa in Rubus (Rosaceae): R. parvifolius, R. coreanus, and R. × hiraseanus, a presumed spontaneous hybrid between the former two described by Makino in 1902, were investigated cytologically. The somatic chromosome numbers were found to be: 2n=14 for R. parvifolius and R. coreanus and 2n=21 for R. × hiraseanus. The chromosome number of the latter was determined for the first time. The karyological features of R. parvifolius and R. coreanus were similar, and further gross similarity was also observed in the chromosomes of R. × hiraseanus, although the size of the satellites and ploidy level differed. The chromosome configurations found in the PMCs of R. × hiraseanus displayed frequent trivalent formation, indicating that R. × hiraseanus may comprise three homologous sets of chromosomes. This study indicated the possibility of a close relationships, but failed in elucidating an origin for R. × hiraseanus.
TL;DR: Detailed karyomorphology of five morphotypes of taro is reported and the degree of karyotypes difference noticed is pointed out to shed light on the possible role of intraspecific karyotype changes and its bearing on the plant morphological difference evident in the species complex.
Abstract: Detailed karyomorphology of five morphotypes of taro is reported. Although in gross karyomorphology Morphotypes I-IV were similar, with respect to finer details of morphology of certain individual chromosomes, recognisable difference was noticed between and among them. Between Morphotypes I-IV and Morphotype V there was striking difference in karyomorphology, particularly in the frequency of m-and st-type chromosomes.The degree of karyotype difference noticed is pointed out to shed light on the possible role of intraspecific karyotype changes and its bearing on the plant morphological difference evident in the species complex. The gross karyomorphological difference noticed between Morphotype V and the others is pointed out to be of taxonomic implication.
TL;DR: It was observed that certain new karyotypes were originated due to chromosomal rearrangements, while the ploidy level remained same as that of original plant.
Abstract: Structural aberrations of chromosomes of 150-day-old cultured cells of barley were examined by karyotypic analysis. Minor and major rearrangements were detected in chromosomes; all the metaphase cells analysed from the culture revealed the presence of aberrant chromosomes in them. Analysis of cultured diploid karyotypes showed the inclusion of 44% structurally aberrated chromosomes. It was observed that certain new karyotypes were originated due to chromosomal rearrangements, while the ploidy level remained same as that of original plant. Tetraploid cells carried greater frequency of aberrant chromosomes that diploid cells. Aneuploid cells of the culture also carried 48% structurally altered chromosomes in them. The significance of this study is discussed.
TL;DR: Karyological details have been investigated in 12 morphologically distinct species/forms including both cultivated and wild occurring putative progenitors of domestivated Vigna species, and difference in the pattern of karyotype evolution in asiatic and african wild taxa was assessed.
Abstract: Karyological details have been investigated in 12 morphologically distinct species/forms including both cultivated and wild occurring putative progenitors of domestivated Vigna species Data on chromosome number, morphology, nucleolar organizers, symmetry/asymmetry of the karyotypes has been recorded The pattern of karyological differentiation and karyotypic evolution in the asiatic wild taxa vis-a-vis cultivated forms has been discussed Difference in the pattern of karyotype evolution in asiatic and african wild taxa was also assessed
TL;DR: The chromosome analysis and in situ DNA estimation of Ornithogalum thyrsoides revealed the maintenance of normal karyotype in leaf and bulb explants, in 300 days old calli and in roots and shoots of regenerated plants.
Abstract: The chromosome analysis and in situ DNA estimation of Ornithogalum thyrsoides (2n=12) in vitro revealed the maintenance of normal karyotype in leaf and bulb explants, in 300 days old calli and in roots and shoots of regenerated plants.
TL;DR: Critical analysis of chromosome morphology revealed the structural alteration of chromosomes along with their changed DNA amount suggesting the compromise between the structural and biochemical changes of the genome during macro- and micro-evolution.
Abstract: A detailed karyotypic analysis and cytophotometric estimation of 4C DNA amount was carried out in six species of the subtribe Carinae of Umbelliferae. Intergeneric and interspecific chromosome number viz., 2n=14, 18, 20, 22 were varied in the subtribe level. Critical analysis of chromosome morphology revealed the structural alteration of chromosomes along with their changed DNA amount. Significant variation of DNA amount having numerical, gross or minor chromosomal alteration leads to the genetic drift in between the species of the subtribe suggesting the compromise between the structural and biochemical changes of the genome during macro- and micro-evolution.
TL;DR: The magnitude of difference between the karyotypes of these two morphotypes was striking and it appears to be more than what can be accounted for by mere structural changes of chromosomes of one type leading to the other.
Abstract: Detailed karyomorphology of two morphologically distinct varieties of diploid taro (Colocasia esculenta) was studied. The karyotypes of the two morphotypes were found to be different in gross karyomorphology. The magnitude of difference between the karyotypes of these two morphotypes was striking and it appears to be more than what can be accounted for by mere structural changes of chromosomes of one type leading to the other. A taxonomic separation of the two morphotypes may be worth consideration.
TL;DR: In this article, the cytogenetic effects of gesagard and igran, which are isomers of each other among herbicides of triazine group, in barley have been studied comparatively.
Abstract: In this study, cytogenetic effects of gesagard and igran, which are isomers of each other among herbicides of triazine group, in barley have been studied comparatively. The fact that barley seeds have been treated with 10-2 (1%) g/100cm3 aqueous solution of herbicides, gesa-gard and igran for 12 and 24 hr, has caused to decrease significantly the mitotic index (MI) of root tip cells.By the treatment of barley with gesagard for 12 hr, C-metaphase has been obtained. In this group, 63.33% C-metaphase has been observed. On the other hand, C-metaphase has been observed in a small amount in the other groups, in which barley has been treated with gesagard and igran for 24 hr. Besides, gesagard has caused chromosome contraction.
TL;DR: Measurements of erythrocytes and their nuclei confirmed the di-tetraploid relationship of the parental species and non-intermediate pattern of the hybrid genome.
Abstract: Hybrids between the great sturgeon and the Russian sturgeon in reciprocal crosses are found to exhibit non-intermediete chromosome number, 2n=167-169, on average. The hybrids are also characterized by sharp increase in variability of the quantitative karyotypic parameters such as diploid chromosome number, bi-armed chromosome number, number of uni-armed and microchromosomes, and chromosome arm number. Measurements of erythrocytes and their nuclei confirmed the di-tetraploid relationship of the parental species and non-intermediate pattern of the hybrid genome. Sharp disbalancing of karyotype of both reciprocal hybrids is indicative of high probability of their complete sterility.
TL;DR: It is demonstrated that with the technique devised, tissues of the embryo can be successfully utilized for chromosome analysis in this family and for the comparative study of the chromosome complements choice of similar organ is essential.
Abstract: Detailed analysis of chromosomes was undertaken in Lathyrus sativus, Pisum sativum, Crotalaria juncea, Trigonella foenum-graecum, Dolichos lablab, Phaseolus mungo, P. vulgaris, and Glycine max of Leguminosae with the aid of improved methods in both root and embryonic cell. Data on mitosis in tissues of embryo is hitherto unrecorded. The present investigation has demonstrated that with the technique devised, tissues of the embryo can be successfully utilized for chromosome analysis in this family. However, for the comparative study of the chromosome complements choice of similar organ is essential.
TL;DR: There was remarkable similarity between sexes in chromosome morphology, number of secondary constrictions and total chromosome length, as well as the amount of 4C DNA.
Abstract: Analyses of the structure and behaviour of chromosomes and estimation of 4C nuclear DNA in both male and female plants of Coccinia indica and Trichosanthes dioica were made. In male and female plants of T. dioica had identical chromosome numbers. There was remarkable similarity between sexes in chromosome morphology, number of secondary constrictions and total chromosome length, as well as the amount of 4C DNA. In absence of any detectable chromosomal differences it may be argued that the sex determination in this species is principally controlled at the autosomal level. The karyotypes of male and female individuals were not markedly different in C. indica, except for the sex chromosomes. The total chromosome length was slightly more in male as compared to female plant. There was a corresponding difference in 4C DNA values. The differences in chromosome size between sexes of C. indica reflected additional chromatin rather than differential condensation. The heterochromatic nature of long sex chromosome was also indicated in its staining behaviour. The total chromosome length, average chromosome length and the 4C nuclear DNA values of both males and females of annual T. dioica were comparatively higher than those of the related perennial, C. indica.
TL;DR: The paper evaluates the degree of polyploidy in the leguminous genus Crotalaria, and discusses its role in intrageneric evolution, impact on plant fertility and significance in solving the problem of base number of the genus.
Abstract: The paper evaluates the degree of polyploidy in the leguminous genus Crotalaria, discusses its role in intrageneric evolution, impact on plant fertility and significance in solving the problem of base number of the genus.
TL;DR: In pearl millet, a mutant with plasmodial sporocyte (syncyte) formation, chromatin disintegration, desynapsis and centromere breakage was identified and its cytogenetic features were studied, resulting in progeny with completely normal cytological behaviour.
Abstract: In pearl millet (Pennisetum americanum (L.) Leeke, n=7), in the selfed progenies of a line L. S. 326-3, a mutant with plasmodial sporocyte (syncyte) formation, chromatin disintegration, desynapsis and centromere breakage was identified and its cytogenetic features were studied. Two to 24-nucleate syncytes were formed due to suppression of cytokinesis during premeiotic mitoses. In syncytes, chromatin degeneration occurred from prepachytene to telophase I stages, thereafter only masses of empty cytoplasm were found. In uninucleate PMCs, chromatin extruded in prepachytene stages in some, degenerated upto diakinesis in several, and either bivalents or univalents (ranging from 1 to 14) were formed in the rest. Centric misdivision leading to telocentric chromosomes (ranging from 2 to 14 per cell) occurred in a proportion of PMCs at anaphase I. There was high sterility of male and female gametes.F2 and test cross progenies of mutant X normal segregated respectively to 9:3:3:1 and 1:1:1:1 ratios of (i) completely normal meiotic behaviour, (ii) syncyte formation and chromatin disintegration but without desynapsis and centromere breakage, (iii) desynapsis and centromere breakage but without syncyte formation and chromatin disintegration and (iv) meiotic behaviour like the original mutant. Crosses between the recombinants (ii) and (iii) above yielded progeny with completely normal cytological behaviour. The original mutant thus was a double mutant. The genes were designated as snd (syncyte formation and chromatin disintegration) and ds cb (desynapsis and centromere breakage).
TL;DR: Determination of the combination of these banding patterns may advance detailed detection of cytogenetical variation among individuals of Aconitum sanyoense.
Abstract: Correspondence of banding patterns of Giemsa C-band and DAPI/CMA fluorochromes of the same specimen of Aconitum sanyoense was examined. It appeared that there were various C-bands, that is, AT-rich (C+/DAPI+/CMA-), GC-rich (C+/DAPI-/CMA+), and intermediate (C+/DAPI-/CMA-) C-bands. Furthermore, some so-called euchromatic segments showed AT-rich DNA sequences (C-/DAPI+/CMA-). Determination of the combination of these banding patterns may advance detailed detection of cytogenetical variation among individuals of this species.
TL;DR: The low incidence reported here of all three cytogenetic end points may possibly reflect the influence of high folate levels in cord bloods on spontaneous chromosomal damage.
Abstract: A cytogenetic monitoring programme on human new borns carried out from 1983-1987 to find out the incidence of constitutional chromosome anomalies also included studies to obtain baseline data on spontaneous chromosomal aberrations (CA), sister chromatid exchanges (SCEs) and micronuclei (MN) from cord blood samples in limited number of human neonates. The results are compared with data obtained in our laboratory on these cytogenetic end points from adult peripheral blood lymphocytes. The micronuclei data was obtained from adult lymphocytes by the cytokinesis blocked lymphocyte assay, by Cytochalasin B. 120 cord blood samples analysed gave a mean frequency of 0.0052 chromatid breaks/metaphase and 0.0059 chromatid gaps/metaphase. Only one dicentric chromosome was noticed in the 12, 000 cells analysed. No statistically significant difference was noticed between male and female new borns in the spontaneous CA frequency. 20 adult blood samples analysed after 48 hr culture and 10 adult blood samples analysed after 72 hr culture gave mean frequency of 0.0085, 0.013 chromatid breaks/metaphase and 0.01414, 0.019 chromatid gaps/metaphase respectively. A large statistically significant elevation in SCE/cell was found when adult blood samples were compared to cord blood samples (the difference 1.94 SCE/cell, P<0.001 by simple ‘t’ test) the mean frequency of SCEs observed in cord blood samples and adult samples being 5.56±0.21 and 7.496±0.21 SCE/cell respectively. The frequency of micronuclei in cord blood lymphocytes was found to be 0-1.5/1000 cells, 1-3/1000 cells, 2-5/1000 cells in 48, 72 and 96 hr cultures respectively. Adult blood lymphocytes exhibited a micronuclei frequency of 0.0123±0.001 MN/CB cell. The low incidence reported here of all three cytogenetic end points may possibly reflect the influence of high folate levels in cord bloods on spontaneous chromosomal damage.