Chromosome damage induced by R7372 was investigated in Nigella damascena seeds (doses ranging from 31 to 155 × 10-5 M) and root tips (doses ranging from 0.97 to 15.6 × 10-5 M). Chromosome damage consisted in fragments, microfragments and gaps. There was also a chromosome uncoiling effects of R7372 and a synergistic effects with colchicine for metaphase accumulation. A linear relationship between dose and total effect was established for both seeds and root tips. The damage and the sensitivity of various phases of the mitotic cycle could be compared with the effect of another nitronaphtofuran (R7000).
Aegilops variabilis (2n = 4x = 28, UUSS) with a high level of resistance to Karnal bunt (Tilletia indica); an important soil-borne disease; is a potential genetic variability source for transfer to wheat (Triticum aestivum L.). Diagnostic markers using proteins and isozymes have hence been established to detect the presence of Ae. variabilis chromosomes in Triticum background. High molecular weight glutenins (HMW-Glu), glucose phosphate isomerase (GPI), seed esterase (EST-5), glutamate oxaloacetate transaminase (GOT), 6-phosphogluconate dehydrogenase (6-PGD), a-amylase (α-AMY) and β-amylase (β-AMY) were positive biochemical markers. These markers enable identification of the disomic chromosome additions of Ae. variabilis to wheat and also determine their homoeology with the homoeologous groups of wheat following evaluation of their respective amphiploids; T. aestivum/Ae. variabilis (2n = 10x = 70) and T. turgidum/Ae. variabilis (2n = 8x = 56).
Seed set on self-sterile intergeneric hybrids occurs as a consequence of induced amphiploidy, backcrossing or by trigeneric hybridization. In this study a self-sterile F1 hybrid of Triticum aestivum/Leymus racemosus (2n = 5x = 35) upon pollination by Thinopyrum elongatum (2n =10x = 70) yielded derivatives that possessed 35 to 70 chromosomes. The single 35 chromosome derivative is considered to be the product of parthenogenetic egg-cell development (apomictic) while the 70 chromosome derivatives resulted from the fertilization of a 35 chromosome egg cell with pollen from Th. elongatum. When 56 chromosome backcross I .T. aestivum/L. racemosus//T.aestivum plants were pollinated by Th. elongatum trigeneric derivatives of normal chromosomal composition were obtained.
Cytological studies were carried out in zira of Iran, comprising Bunium persicum, B. cylidricum, B. chaerophylloids, Cuminum cyminum and Carum carvi. Somatic chromosome number determined were 2n =14, 20, 12 and 14 respectively. High coefficient of correlation for total chromosome length indicated presence of a homogenous group. However low correlation values for short arm length, long arm length and 1/s ratio indicate occurrence of structural changes of chromosomes, among different populations of each species. Cluster analysis of karyotypic data showed similarity between some of the populations. Cophenetic correlations obtained from comparisions of clusters with original data showed a good fit of analysis. Different method of clustering produced the same results, indicating distinctness of clusters. Meiotic analysis with regard to chiasma distribution showed lack of heterogenity among different populations and between the species studied.
One ml each of sterile aqueous solutions of aspirin (acetyl salicylic acid) at 1 μg/ml, 10μg/ml and 100 μg/ml were injected intraperitoneally into different inbred Swiss albino mice ofabout 30 g weight. After 24 hr, bone marrow was extracted from the femurs and cytological preparations were made. There was a marked depression in the mitotic indices of the bone marrow cells, in treated mice corresponding to the concentration of aspirin compared to that of controls. Mitotic arrests and apindle abnormalities were also encountered. The drug was also capable of inducing chromosome fragmentation, pulverization, stickiness and sticky bridges. These observation clearly show that aspirin is both mitoclastic and clastogenic even at very low concentrations, and hence its indiscriminate use has to be discouraged.
Karyotypes (chromosome number and shape) of eight species of the Drymadusini group were studied. The chromosome numbers in this group range from 2n_??_ = 25 to 31. Cytological analysis of these species indicate the presence of a more intensive karyotype evolution than in other genera of the Old World Decticinae. Additionally, C-band distribution and chromosomal location of the NORs were studied. Paracentromeric, interstitial, and distal C-banding in this species was observed. Three of the five analysed species showed a single active NOR located on the M2 bivalent, whereas two active NORs (primary and secondary) were observed in the two remaining species.
C. gigantea collected from South India is found to be markedly distinct on both morphological and cytological characters. This species is outstanding in its cytology as it showed the presence of the aneuploid number of 12 distinctly large chromosomes which are rather unspecialized. This is an annual sexual species with normal meiosis and good seed setting. The size of the wings of the lower glume of the male spikelets of C. gigantea collectedfrom Calicut (Kerala) and Gopichettipalayam (Tamil Nadu) are narrower when compared with those of C. lacryma-jobi var. lacryma-jobi (local collection) which has very broad wings. Theleaves are long and narrow when compared with those of C. lacryma-jobi. The present study hasshown that the classification of the four species of Coix by Bor (1960) into two groups based on the size of the wings of the lower glume of the male spikelets appears to be invalid, eventhough C. gigantea agrees with this classification in the other morphological features and the ecological habitat.
Chromosomal aberrations such as gaps and breaks were studied in 15 cases of breastcancers (i.e., stage II-3 cases, stage III-8 cases and stage IV-4 cases) and their 5 normal age and sex-matched controls. The average rate of chromosome gaps and breaks were 1.61, 1.04 and 1.20 in stage II, III and IV breast cancer cases respectively, and 1.36 normal age and sex-matched control. Chi-square comparison showed a significant difference between total breast cancer patients and normal controls (P < 0.05), a higher difference between stage II breast cancer cases and normal control (P < 0.01) and slightly higher difference between stage II and stage III breast cancer cases (P < 0.05). The result so obtained clearly indicate that probably stage II breast cancer is a crucial stage for maximum chromosomal alteration in this malignancy.
In vitro genotoxic evaluation of some of the widely used sex-steroidal hormones viz. ethynyl estradiol, estradiol-17β and estriol were attempted. Human lymphocyte culturs for the sister chromatid exchange (SCE) assay showed that except for estriol, the other steroidal hormones showed fairly potent DNA damaging activity. The non-mutagenic activity of estriol may due to its week estrogenic potentiality.
One of five different populations of Centella asiatica from the Southern Region of Brazil submitted to cytologic analysis presented chromosome stickiness in 19.30% microsporocytes studied (Praia de Leste population). This phenomenon was observed in both meiotic divisions. The phenotypic manifestation ranged from mild stickiness, with the possibility of recognizing the phases and with meiosis continuing to the end, to intense stickiness manifesting through pycnosis followed by chromosome degeneration, in which the phases of meiotic development could not be identified. These irregularities, taken together with others such as cytomixis, abnormal spindles and irregular chromosome segregation, were probably the cause of low pollen fertility (0.30%) and low production of normal fruits (1.0%).
DNA-fluorescence from nuclei and nucleoids in gametes of Ulva pertusa have beenmeasured after staining with 4'-6-diamidino-2-phenylindol. The nuclei emitted 2.2 times as much fluorescence as that from haploid Chlamydomonas reinhardtii, whose nuclei have been reported to contain 7.2 × 1010 daltones (Chiang and Sueoka 1967) and a GC content of 62.1% (Sager and Ishida 1963). The average nucleoid number of U. pertusa from 100 gametes observed was 7.97±2.60 (S.D.). DNA fluorescence of each nucleoid ranged from 0.27 to 8.0 times as much as that of T4 phage, which has been reported to contain 1.1 × 108 daltons of DNA (Freifelder 1970), with a GC content of 36% (Runder et al. 1969). Total nucleoid DNA-fluorescence in a cell of U. pertusa was 22.4 to 32.3 times as much as tht of T4 phage.
The presence of a Golgi body and a cell wall in Cyanidioschyzon merolae was re-examined by electron microscopy after rapid-freeze substitution fixation to understand the minimum ultrastructural characteristics of eukaryotes. C. merolae cells contained one Golgi body which was composed of one to two cisternae, transfer vesicles and secretory vesicles. A trans-Golgi network was not seen, but association between the transfer vesicles and the nuclear membrane was often observed. The cells did not have a cell wall, but were covered by many filaments which were protruded from a thin electron-dense layer on the exterior surface of the cell membrane.
A characterization of the Ag-NORs is presented for fish species of the Erythrinidae family, comprising the genera Hoplias, Hoplerythrinus and Erythrinus. A highly diversity was observed for the NORs sites, concerning their number and locations on the chromosomes, supporting the view that these regions underwent several chromosomal changes during the karyotypic evolution of this neotropical fish family. A particular situation occurs in the genus Hopliasmalabaricus group, where typical bitelomeric NORs can be seen in some biarmed chromosomes as a clearly populational feature, an infrequent situation in other fish groups or even among the vertebrates in general.
This paper presents an embryological study of Miconia cabucu Hoehne. This species from the Tropical Atlantic Rain Forest occurs and reproduces in disturbed areas such as treefall gaps. The species agrees well with other Myrtales in its basic embryological characteristics, but displays some distinctive featurees : uninucleate anther tapetum cells, and the presence of a funicular obturator. These features may be useful for establishing boundaries between the Melastomataceae and other Myrtales.
This work details the study of a ewe (Ovis aries) of merino breed, in which a case of an autosomal double deletion was found; applying G and C banding techniques it was possible to observe a big segment loss from the pair chromosome no. 3. Concerning the phenotype the ewe was healthy, but with different alterations of some blood physiological parameters. The albumin (39.09%), albumin-globulin ratio (0.64), ALAT (4.9 I.U./l) showed very low values; on the contrary, the value for potassium (5.80 mmol/l) was very high. The electrolyte phosphorus (3.43 mmol/l) shows the highest value, and its associated calcium/phosphorus ratio (0.77) the lowest in the whole herd of 226 sheep.
Bacopa monniera L. (Brahmi) is an annual creeping plant has been extensive1y used in the Indian Ayurvedic medicine as a nerve tonic. A mixture of two saponins Bacoside A and B, which are the active constituents of B. monniera has been evaluated for its genotoxic activities in mice with three cytogenetic end points i.e. chromosome aberrations (CA), sister chromatid exchange (SCE) and micronuclei formation (MN). No significant differences were observed in a11 the three end points tested when compared with negative controls. Thus the overall results indicate that Bacoside A and B is not genotoxic and is safe for medicinal use.
The karyotypes of 17 taxa representing eleven species of Astragalus have been described and their taxonomic inferences are discussed. A diploid chromosome number of 2n =16, with a basic number of x = 8, was recorded in A. eremophilus, two samples of A. peregrinus, A. sieberi, A. sinaicus and A. trigonus. Polyploid numbers, also based on x = 8, were scored, 2n = 32 in A. hamosus and 2n = 40 in A. hamosus v. buceras. Meanwhile, a diploid number of 2n = 14, with a basic number of x = 7 was found in three samples of A. annularis and three varieties of A. tribuloids. A. boeticus was found cytologically distinguished with 2n = 30, and A. tenuirugis with 2n = 24, while A. trimestris has 2n = 12 and x = 6. The chromosomes in the genus Astragalus are relatively samll, among the examined species the largest were found in A. annularis (mean length = 1.7-1.75 gm) and the smallest were recorded in A. boeticus (mean length = 0.95 μm). In general the karyotype of the genus show a relatively high degree of symmetry as reflected by r-value and the TF%. Infra and inter-specific variations, in these criteria, have been recorded among the studied taxa. The preponderance of species with a basic number of x = 8 among the studied taxa agree with the assumption that this number is the primary number in Astragalus, x = 7 and x = 6 could have been evolved by aneuploid loss of chromosomes. This situation is only found in the Old World species of the genus. In the New World species, however basic numbers of x =11, 12, 13, 14 and 15 have been often encountered, these numbers may have been evolved from x = 8 through polyploidy followed by loss of 1-4 chromosomes. Discussion of chromosomal relationships in this large and complex genus chould take into account that only about 25% of the species have been cytologically examined. Moreover chromosomal changes should not be discussed independent of other criteria particularly those of morphology. Among the examined taxa chromosomal features provide evidence for the differentiation of some taxa which share mophological similarities, meanwhile some other taxonomically related species were found to have similar karyotype features.
1. In depth chromosome analysis of a Mysore population (S. W. India) of a tettigonid, Letana nigrosparsa revealed a normal and a variant karyotypes. 2. All the individuals show a diploid number of 29 acrocentric chromosomes (28A + X) including a large X chromosome which measures Ca. 26% of the haploid genome. 3. The normal karyotype was seen in 13 males and the variant karyotype in two individuals. The latter differs from the former in the presence of a pair of sat-chromosomes and a pair of small subacrocentrics. 4. C-banded metaphase is presented showing the characteristic distribution of C heterochromatin. 5. The unique and pecular behaviour of the X chromosome in the spermatogonial cells is described and discussed.
Chromosome number of the two species in the genus Chondria, C. crassicaulis Harvey and C. dasyphylla (Woodward) C. Agardh, belonging to Rhodomelaceae (Rhodophyta) examined for the tetrasporophytes from the vicinity of Hakodate, Hokkaido, was determined as n = 32 at Meiosis I in the tetrasporangia and 2n = ca. 60 in their somatic cells for the both species. The tetraspore-germlings of C. crassicaulis grown up the branched minute male gametophytes in 2 years culture indicated that the chromosome number was 32 or ca. 30 in their somatic cells and in the cells leading to spermatium formation.