Eighty pregnant female mice were alloted among 16 groups. The animals were given intraperitoneal injection equalized to the therapeutic doses used for human. Indomethacin was given (25, 75 mg/kg b.wt.) and cyclosporine-A was given (5, 10, 15 mg/kg b.wt.). They induced significant increase in fetal resorption and significant decrease in fetal body weight. Also, reduction in the sizes of the skeletons of embryos was observed. Dosage of 150 mg/kg b.wt. of indomethacin was the lethal dose to dams. Various chromosomal aberrations in maternal bone marrow cells and embryos cells and mitotic activity were recorded, quantitated and statistically analyzed. Indomethacin (75 mg/kg) induced more chromosomal aberrations in both pregnant females as well as fetuses than the lower dose (25 mg/kg). Cyclosporine-A (15 mg/kg b.wt.) induced an increase in chromosomal aberrations in bone marrow cells of female mice than lower dose (5, 10 mg/kg b.wt.), while no significant differences were observed between the (5, 10 mg/kg) doses. Also, cyclosporine-A (15 mg/kg) showed highly significant increase in chromosomal aberrations in embryos than medium (10 mg/kg) or lower doses (5 mg/kg).
A combination of modified squash and splash techniques was used for a cytogenetic study of mitotic and meiotic cells of Prosopis laevigata. The mitotic karyotype was obtained for the species, and meiotic behavior was monitored from prophase I through the synaptonemal complex (SC). Analysis using light microscopy showed 2n=28, with chromosomes that, depending on the technique employed, varied in length from 0.84 to 1.84 μm in squashed specimens and from 1.0 to 1.82 μm in splashed specimens. These values are larger than those previously recorded for other South American species of the genus. The karyotype was studied by the splash method. The frequency of tetraploid cells was about 11% of 2052 metaphase cells examined. Meiosis was normal, because 14 bivalents were seen at metaphase I. The SC in pachytene showed regular features and an asynchronous pairing pattern with some short segments of lateral elements apically or interstitially unpaired, and occasional partner exchanges between three lateral elements. A constant association of the telomeric end of a bivalent with the nucleolus in mid-and late-prophase suggests the location of an active nucleolus organizer region (NOR) and its relation with a unique pair of mitotic chromosomes with satellites. The techniques employed here are recommended for species not amenable to cytogenetic studies with conventional techniques.
Chromosome numbers of 9 species of Mimosa which grow in the southern limit of the South American centre of diversification were determined, all of them are new reports except the one of M. oligophylla. M. vellosiella, M. oligophylla and M. flagellaris were diploids with 2n=2x=26; M. velloziana and M. adpressa were tetraploids with 2n=4x= 52; M. sprengelii, M rarnulosa and M. rocae were octoploids with 2n=8x=104; and one accession of M. balansae was diploid while the other was tetraploid. All of them were multiples of the basic chromosome number x=13. The polyploid species were more frequent at higher latitudes, this increment was also accompanied with a higher ploidy level of the polyploids southernward. All the polyploids found belong to the sections with most advanced characters of the genus, which supports the phylogeny proposed for Mimosa by Barneby. Data suggest that the extension of the genus toward the temperate zones might have be done mainly by polyploid species, which may have had advantages over the diploids in colonising habitats restricted to the latter.
The aim of this study was to investigate the indirect genotoxic effect of various doses of gamma rays in human peripheral lymphocytes. For this aim, chromosome mediums were irradiated with various doses (2000, 4000, 8000, 16000 rad) of gamma rays. In this study, we were found that SCE (Sister Chromatid Exchange) was increased by gamma rays doses-dependently. In addition to these, percentages of abnormal cells with chromosomal abnor-malities and CA (Chromosome Aberration) /Cell were increased by all doses of gamma rays com-pared to control. Besides, gamma rays decreased the MI dose-dependently. RI was not also reduced at all concentrations.
Cytological studies in Musa spp. L. are hampered by the small size and poor staining ability of the chromosomes. The aim of this experiment was to use silver nitrate as a staining agent for Musa chromosomes. The results of this study showed that silver nitrate is a useful alternative stain for cytological studies in Musa. The silver staining procedure was very effective for demonstrating the structure of prophase stages of meiosis.
Hoplerythrinus unitaeniatus fish from 5 different locations in South America were cytogenetically studied. Five populations from Corrientes (Argentina), Miranda (Mato Grosso do Sul State, Brazil), Porto Velho (Rondonia State, Brazil), Parque Estadual do Rio Doce (Minas Gerais State, Brazil) and from the Paramaribo region (Surinam) were analyzed. The specimens from Corrientes, Miranda and Porto Velho presented a diploid number equal to 48, all M-SM chromosomes, with a fundamental number (NF) equal to 96. The specimen from Surinam had 2n=48 (46 M-SM + 2 A) and NF =94. The specimens from Parque Estadual do Rio Doce had 2n =52 (46 M-SM+6 A) and NF=98. These structural and numerical chromosome variations among H. unitaeniatus populations suggest that Hoplerythrinus may not be a monotypic genus as presently thought.
The genotoxic effect of hexavalent potassium dichromate (K2Cr2O7) was investigated in mice in vivo using sister chromatid exchange (SCE) and chromosomal aberration analysis. K2Cr2O7 induced a significant increase in the frequency of SCE's after intraperitoneal (i.p.) treatment with the doses 6, 12, 24 mg kg-1b.wt. which correspond to 1/8, 1/4 and 1/2 of the experimental LD50. The lowest tested dose 3 mg kg-1b.wt. had no effect with respect to SCE's and its effect reached 6.57 ± 0.36/cell compared with 5.80± 0.55/cell for the control. The frequency of SCE's reached 9.03 ±0.20 after treatment with the highest tested dose of K2Cr2O7, a value which is less than that induced by mitomycin C (13.10 ± 0.40) as the positive control. Thiola at the concentrations of 20 and 50 mg kg-1b.wt. had moderate but non-significant effect for minimizing the frequency of SCE's induced by different doses of K2Cr2O7. With respect to chromosomal aberrations, all the tested concentrations of K2Cr2O7 (3, 6, 12, 24 mg kg-1b.wt.) induced a significant increase in the percentage of chromosomal aberrations in mouse bone marrow as well as in mouse spermatocytes 24 h after single i.p. treatment. The incidence of chromosomal damage increased significantly with increasing the dose. However mitomycin C induced higher effect. The results also show that the pretreatment with thiola at the dose of 50 mg kg-1b.wt. significantly reduced the percentage of chromosomal aberrations induced by K2Cr2O7 in all the treatment groups and the results confirm the protective role of thiola which has been proved previously against the genotoxicity of some mutagens.
Soluble proteins from the specialised reproductive structure, the tuberous roots of Momordica dioica Roxb. through which it propagates, were analysed by SDS-PAGE to compare the protein profiles of the sex forms. Twenty eight bands with molecular masses ranging from 15 kD protein to more than 94 kD proteins were found to be common in both sexes. The difference in their protein profiles was marked by the presence of a 22 kD polypeptide (p-22) in the female sex which was not detected in its male counterpart. Further studies by immunoblot assay demonstrated that antibody raised against p-22 not only cross-reacted at 22 kD antigen of the female sex but also with 29 kD and 32 kD polypeptides of the male and female sex forms. It indicates that these 3 polypeptides are electrophoretically distinct but antigenically similar. 22 kD protein found in female sex is, therefore, not sex specific rather sex linked. Moreover, variation in the intensity of 29 kD and 32 kD polypeptides of male and female sex forms suggests that the interplay of these 2 sex linked polypeptides may be a contributing factor in controlling sex mechanism of dioecious Momordica dioica.
Several cases of B chromosomes have been described for neotropical fish species. In some fish groups, this occurrence is sporadic, whereas in others it is more frequent. A high frequency of a metacentric macrochromosome B has been reported for Astyanax scabripinnis populations from different locations. In the present study, this kind of chromosome is reported for the first time in 2 other species of the same genus, A. fasciatus and A. schubarti. This coincidence, as well as the differential B chromosome frequency among the 3 Astyanax species, permit some considerations about its probable common origin and further distribution in this fish group.
Cytogenetic data are given for 3 species of Auchenipteridae family. Auchenipterus nuchalis and Parauchenipterus galeatus were caught in the river Paraná and Glanidium ribeiroi is an endemic species from the river Iguacu. The 3 species have 2n=58 chromosomes, albeit with differences in the karyotypic formulae. Changes in the karyotypic formulae associated with the same chromosome number suggest that the karyotypic evolution in the family may be related to nonRobertsonian changes. Pattern of heterochromatin distribution is similar to that in the majority of Siluriformes in which small blocks in the centromere and telomere regions occur. The nucleolus organizer regions (NOR) were detected in only one chromosome pair, a primitive condition in fishes. A. nuchalis and G. ribeiroi have NOR in interstitial position, a relatively rare condition in neotropical Siluriformes and shared by another 2 species of the Doradoidea superfamily.
The effect of the molluscicide “Uccmaluscide” on mitosis and meiosis of Vicia faba has been studied. Mitotic activity of Vicia faba root tip cells decreased and produced different kinds of chromosomal abnormalities after treatment with different concentrations. Vicia faba plants were sprayed at flowering stage with the different concentrations of uccmaluscide solution. The percentage of abnormal pollen mother cells increased as the concentration increased. The most dominant types of abnormalities were stickiness, bridges, fragments of chromosomes, disturbance of mitotic stage and littlepolar or multipolar cells. Less than 4 spores were the dominant type of abnormalities observed in the quartet stage. Nonviable pollen grains were observed in addition to the small pollen grains.
The insecticide cyolan was examined for the induction of mitotic and meiotic abnormalities and changes in the banding patterns of M2 seed storage protein in Vicia faba plants. The used insecticide solution had mitodepressive effect and induced a wide range of mitotic and meiotic abnormalities. On the protein level, the results for the 3 major fractions of seed storage proteins in Vicia faba, as revealed by SDS-polyacrylamide gel electrophoresis, showed mutagenic effects for insecticide. In general, all treatments caused decrease in the amount of proteins.
A close relationship has been verified between presumedly GC-rich conspicuous segments and the nucleolus organizer regions on chromosomes of cold-blooded vertebrates. C-banding, and chromomycin A3 (CMA) or mithramycin A (MM) staining as well as rDNA in situ hybridization were performed in mitotic chromosomes of a population of the characid fish Astyanax scabripinnis in order to study GC-rich heterochromatin and the pattern of nucleolar rDNA location. The results showed a close relationship between large telomeric heterochromatic segments and GC-specific fluorochrome bands. Some CMA+ (or MM+) bands presented no correspondence with nucleolar rDNA sites detected by fluorescence in situ hybridization (FISH). Although GC specific fluorochromes have been widely used to infer nucleolus organizer regions location in fish chromosomes, a detailed FISH analysis indicates that, in this population, rDNA clusters are not always located on CMA+ (or MM+) bands, and some GC-rich bands do not bear rDNA clusters. Based on some available models we discussed some possible mechanisms for the non-random nucleolar rDNA and CMA+ heterochromatin distribution in A. scabripinnis chromosomes.
Primer extension analysis using 10 μg of polyA RNA extracted from zygotes of Chlamydomonas reinhardtii 10 min after mating was carried out to elucidate relative amounts of transcripts of early zygote-specific (zys1) genes. A novel minor extension product as well as a major product for each of the zys1A and zys1B genes was detected. Quantification of band intensity showed that relative accumulation amounts of zys1A major, zys1A minor, zys1B major and zys1 minor transcripts were in the ratio of 1.78 0.171 : 1.00 : 0.730. This result suggests that the zys1A promoter is slightly stronger than that of zys1B at an initial stage of gene expression.
In order to investigate the protein components specific for mitochondrial (mt-) nucleoids, mt-nucleoids isolated from yeast Saccharomyces cerevisiae were analyzed by means of twodimensional (2D-) gel electrophoresis. More than 40 proteins of mt-nucleoids were visualized on a 2D-gel, ranging from acidic to basic pH. Among them, the protein with the most basic property was a 20-kDa protein, Abf2p. Of the 13 proteins, which are abundant in mt-nucleoids, 6 proteins corresponded to those that were separated from mt-nucleoids by means of DNA cellulose chromatography. The 11 proteins among those were discerned to be significantly concentrated in isolated mt-nucleoids when compared with whole mitochondrial protein. The distribution of mt-nucleoid proteins on a 2D-gel was quite different from that of cell nuclear proteins, and the nuclear histones were hardly detected in mt-nucleoid fractions. These results indicated that a specific subset of mitochondrial proteins are associated with mtDNA to form mt-nucleoid structures.
By means of morphological and chromosomal analyses it is considered that the Himalayan species Trillium govanianum is an intergeneric hybrid between Trillium and Daiswa. Trillium govanianum is an allotetraploid (4x=20) that most likely has originated from the 10 GG genome of a plant in the genus Trillium and the 10 DD genome of a plant from the genus Daiswa. Factors concerning the emergence of the polyploid species have been discussed from an evolutionary viewpoint and on a consideration of the paleoclimatics in the Himalayan mountain region.
Previous study demonstrated that the ftsZ gene expressed specifically in pollen generative cells of Lilium longiflorum was also found to be expressed during microsporogenesis before formation of them. We, therefore, proved the expression of L. longiflorum FtsZ (LlFtsZ) in uninucleate microspores with specific antibodies. As a result, rings were visualized in the cytoplasm of young microspores. Moreover, it was revealed that almost all rings overlapped on each of plastids by 4', 6-diamidino-2-phenylindole (DAPI) staining. Each spherical and peanut-shaped plastid had one ring on its equator. These results suggest that FtsZ ring is required for plastid division.