Karyotypes of six species of birds have been reported, these include, Passer domesticus and Locustella fluviatilis (Passeriformes), Tyto alba (Strigiformes) and Porphyrio porphyrio (Gruiformes) with diploid chromosome numbers of 76, 72, 92 and 80, receptively, Egretta gularis and Botaurus stellaris (Ciconiiformes) have the same diploid number of 62 but their karyotypes are clearly different.
Akodon azarae is one of several rodent species in whose populations XY fully fertile females are found. The chromosomes of 83 specimens (40 females, 43 males) from three localities were studied. A high incidence of XY females was observed : 21 of the females presented an XY karyotype. The X chromosome relative length corresponded to 8.2% of the genome, but a significative portion of it consisted of C-positive material, giving to the euchromatic part a relative length of 5.07%, in agreement with the estimated size of the eutherian X. Four C-banding patterns (I-IV) of the X chromosomes were observed, one of them found in only one specimen. The X chromosome of males was type I, and XY females showed an X of type II or III. XX females presented one X of type I and the other of type I, II, III or (in only one animal) of type IV. The significance of this polymorphism with respect to the XY female phenotype is briefly discussed.
Three species of the Vicia narbonensis complex, namely V. narbonensis L., V. kalakensis Khattab, Maxted et Bisby and V. eristalioides Maxted were analysed for different karyobiological features; the nuclear DNA content and DNA absorption curves were determined, karyomorphometric data were generated using an automated image analysis system and the distribution and staining properties of heterochromatin in metaphase chromosomes, were assessed. Feulgen absorptions at different thresholds of optical density provided evidence of organisation of the chromatin interphase nuclei and allowed an evaluation of the heterochromatin amount as determined with a cytophotometrical approach. The precise chromosomal measurements were utilised for computing karyomorphological indices.
A tissue culture protocol using leaf sheath as the explants has been established for callus induction and for plant regeneration of eastern gamagrass. An MS basal medium supplemented with 2, 4-D, kinetin, and zeatin was used to induce friable calli and to form plantlets in vitro. Ethylmethane sulfonate applied at a concentration of 0.01% on calli appeared to be effective in inducing variation, as shown in the electrophoretic patterns from leaf protein extracts. This protocol has served as a basis for establishing cell suspension cultures for mutagenesis experiments with a goal of inducing a low-lignin mutant of gamagrass with a high level of digestibility and efficiency of use by ruminant animals.
The orange, yellow and pink flowered varieties of Zinnia elegans L. possessed 2n=24 metacentric chromosomes of each. The orcein-stained interphase nuclei and prophase chromosomes revealed the existence of facultative heterochromatin in the orange and yellow flowered varieties. Four CMA-positive terminal bands were observed in the orange and yellow flowered varieties whereas only two CMA-positive terminal bands appeared in the pink flowered variety. In all these varieties, a prominent CMA-positive band of same size (1.2 μm) was found. Only one DAPI-positive band appeared in the orange flowered variety. A bright DAPI-positive band was found at the centromeric region in each chromosome of the yellow flowered variety. No DAPI band was observed in the pink flowered variety. The activity of peroxidase was similar in all these varieties. However, the three varieties showed different activities for esterase and acid phosphatase. Isozyme analysis indicates that activities of esterase and acid phosphatase were less in the orange variety than the other two. Thus, application of fluorescent bandings together with isozyme analysis was able to distinguish the intervarietal diversification in Z. elegans.
The aim of this work is to demonstrate occurrence of GIS (Gene Inactivation System) during the mitotic haploidisation of a diploid strain of Aspergillus nidulans, heterozygous for a duplicated segment. The DWM strain bears Dp (II, I) duplication and has already been submitted to GIS. This strain was used to make the DWM-Aza/PabaA diploid strain after 5-Azacytidine treatment. Dp (II, I) is a II → I insertional duplication including Acr, w and meth + genes. Mitotic segre-gants were obtained from DWM-Aza//PabaA diploid strain which showed inactivation of duplicated genes only These results were confirmed by the gene reactivation achieved by demethylating treatment of the mitotic segregants with 5-Azacytidine. GIS effect was also observed during the sexual cycle of the mitotic segregants, showing that the demethylating treatment makes the duplicated genes very sensitive to GIS. The reduction of the ascospore viability per cleistothecium has also been demonstrated and it has been related to GIS action during the sexual cycle of the duplication strains of A. nidulans.
Chromosome studies of Dalton's lymphoma (DL) revealed only one rb-marker in the cells and the chromosome numbers varied between 59 and 68 with a peak at 66 chromosomes. Thus, the modal number of chromosomes of this DL is suggested to be 66. Cisplatin treatment of tumor bearing hosts resulted the regression of the tumor and induced the formation of chromosomal aberrations/aberrant metaphases (80-90%) in the DL cells which may be responsible for the anticancer activity of cisplatin. Cisplatin treatment of the hosts caused the significant decrease in GSH levels in DL as well as bone marrow cells. Cisplatin's mutagenic potentials in the host is also supported from the observation of the induction of chromosomal aberrations in the bone marrow cells of the same host. Differential effect of cisplatin on the chromosomes of bone marrow and Dalton's lymphoma cells is noted. Bone marrow cells developed significantly less aberrant metaphases as compared to that of DL cells after cisplatin treatment in vivo. Interestingly, aberrant metaphases in bone marrow cells decrease appreciably with time of treatment (48-96 hr) which may suggest the possibility of an efficient clearance/repair of Pt-DNA adducts in bone marrow cells but in DL cells it remained more or less constant.
Cytological studies were carried out based on eleven species in seven families of climbers from the Santa Genebra Forest Reserve : Canavalia parviflora, Canavalia picta, Centrosema sagitattum, Phaseolus lunatus (Fabaceae), Dalechampia pentaphylla (Euphorbiaceae), Mascagnia anisopetala, Stigmaphyllon lalandianum (Malpighiaceae), Merremia macrocalyx (Convolvulaceae), Momordica charantia (Cucurbitaceae), Passiflora miersii (Passifloraceae). Their chromosome numbers and its distribution inside their genera were analyzed. In eight species the chromosomes were measured and for three of these species it was possible to construct the chromosomal ideograms based on karyological data. Five of these chromosome counts were made for the first time.
Ten specimens of Hypostomus sp. from the Araguaia basin (Barra do Garcas, MT, Brazil) were cytogenetically studied, with characterization of the constitutive heterochromatin and positive segments for the fluorochrome Mithramycin. It was detected a chromosomal heteromorphism related to sex, of the ZZ/ZW type, not observed yet in Hypostomus catfish. Thus, in male karyotype can be found one pair of subtelo-acrocentric Z chromosomes, represented by a unique component in female karyotype. However, this latter has an exclusive metacentric the W chromosome. The available data indicate that the differentiation of this sex chromosome system may have occurred by a pericentric inversion, followed by length reduction in an ancestral chromosome similar to the Z one, originating a W chromosome like that now observed in the female karyotype of this fish species.
Microtubular cytoskeleton of free endosperm nuclei during division in wheat was investigated using immunofluorescence labeling technique and confocal scanning laser microscopy. During interphase, microtubles forming a cage around a free nucleus were observed and the orientations of microtubuls (Mts) paralleled to long axis of the ellipsed-shaped free nucleus. During prophase, the orientation of the perinuclear Mts changes from parallel to long axis of a free nucleus to vertical to it, and subsequently the Mts constituted directly metaphase spindle Mts while the nuclear envelope broke down. Spindle Mts were observed during both metaphase and anaphase. A short lived cell plate was deposited in the just formed phragmoplast at either late anaphase or early telophase, but it disappeared subsequently resulting in the failure of cell wall formation. The perinuclear Mts were reconstructed initiating from the daughter nuclear envelopes at early interphase stage. The results suggested that changes of the Mts orientation during prophase might be associated with the determination of plane of nuclear division and the perinuclear Mts had a role in maintenance of the shape of interphase nuclei in syncytium of wheat endosperm.
A first description of the karyotype of Yulong vole (Eothenomys proditor) is presented. Karyotype studies were carried out using conventional staining, G-banding, C-banding and silverstaining. Yulong vole was sharp different from other allied voles on karyotype. The diploid number is 2n=32, with the fundamental number of 56. The autosomes consist of 13 pairs of meta-/submetacentric elements and two pairs of arcrocentric elements. The X chromosome is medium sized and submetacentric, whereas the Y chromosome is small and subacrocentric. The G-banding allows to identify chromosome pairing and to detect the chromosome rearrangements intervening in karyotypic differentiation. In the C-banded karyotype, the centromeric heterochromatin is observed in Nos. 2, 4 and 12 chromosomes, the terminal C-band is found in No. 13 and X chromosomes. Y chromosome is completely C-band-positive, moreover, the interstial distribution of C-bands has been demonstrated on the biarm of No. 2 chromosome pair and the long arm of Nos. 2, 9 and 10 chromosomes respectively. Nucleolus organizer regions (NORs) appeared in the long arm of Nos. 1, 2 and 4 chromosomes and short arm of No. 11 chromosome.
Dugesia species of Karaj river in Iran were investigated from cytologial, and morphoanatomical point of view. Two different populations were studied. Individuals from Gajereh region possessed 2n=25 and those of Gachsar possessed 2n=26. They varied in details of karyotypes, G-Banding pattern and morpho-anatomical features. Cluster analysis separated the two populations of Dugesia in different clusters. Two new species of Dugesia with new chromosome number having complete asexual reproduction are reported.
Chromosome numbers for 13 species, including 12 new counts, were reported for Carex distributed in the Ryukyu Islands. Intraspecific aneuploidy (sensu lato) was found in four species and the different types of chromosome number variation pattern within and among populations were recognized in this study. In three species, C. fulvo-rubescens, C. nemostachys and C. sakonis, several intraspecific aneuploid cytotypes were found in the same population. Additionally, notable disturbances of chromosome associations at meiosis were often observed, especially in C. sakonis, and therefore the compatibility among aneuploid cytotypes of these species was readily predictable. In C. sociata, on the other hand, no chromosome number variations within populations and stable chromosome associations at meiosis were found in all investigated populations, and suggesting that these aneuploid cytotypes have differentiated at least to the population level. These two types of variation pattern may indicate that the different aneuploidy mechanisms have operated in Carex population differentiation.
A dioecious plant, Cannabis sativa has two sex chromosomes (X and Y). The genome sizes of the diploid female and male plants were determined to be 1636 and 1683 Mbp, respectively, by flow cytometry. By the karyotype analysis, the X and Y chromosomes were found to be submetacentric and subtelocentric, respectively. The Y chromosome had the largest long arm with a satellite in the terminal of its short arm. Conspicuous condensation was specifically observed in the long arm and satellite of the Y chromosome during the prometaphase to metaphase stages. These results indicate that the Y chromosome, especially in its long arm, specifically differentiates in Cannabis sativa and might contribute to the sex determination.