C-banded Chromosomes Research Articles

Spontaneous Diabetic NSY Mice: Pathophysiology and Renal Lesion

Spontaneous diabetic mice (NSY: Nagoya Shibata Yasuda mice) used in the present experiment were selective breeding of JCL/ICR mice (supplied by Shionogi Pharmaceutical Co., Abrahi Laboratories) . They are of the same origin as NOD mice. The C-band chromosome analysis made by Dr. Moriwaki, however, shows that NSY mice are clearly different from NOD mice in the genetic background. This NSY mice are considered the model animals for NIDDM (non insulin dependent diabetes mellitus) from some endocrinological viewpoint.Results: 1. Histologic findings of kidney in NSY mice: We found that about the glomerular tissue under a light microscope in NSY mice, an increase in mesangial cell and matrix is observed. This finding was corroborated by electron microscopic observations. And an increase of basement membrane-like material in the mesangial area was seen. The fluorescent pattern with FITC labelled rabbit anti-mouse IgG was observed mainly in the mesangial pattern and partially in the capillary pattern. Fluorescent patterns similar to those with IgG were obtained with IgA and IgM as well. These fluorescent patterns increased in intensity with aging.Since immune globulin settles in the glomerulus as mentioned earlier, electron microscopic observations were made in more details. As a result, the massive dense deposits were noted in mesangial area. 2. Immunological study: 1) Lymphocyte subset of splenocyte was determined in NSY mice, NOD mice and C57BL mice by the complement dependent cytotoxicity test. As a result, acceleration of the helper/inducer system was shown in NSY mice. 2) IgG circulating immune complex (IgG-CIC) was determined in three groups mice by polyethlenglycol technique. With NSY mice, IgG-CIC significantly increased to be contrasted with control group. 3) The glomerulus of NSY mice was stained with fluorescent gp70 antibody in cooperation with Dr. Tomino (Tokai University School of Medicine) . A pattern of deposition was seen mainly along the capillary wall. This findings suggest the presence of retro-virus. This suggests a possibility of the immune complex being formed with an antibody against retro-virus.

Identification of Allium cepa L. cultivars by means of statistical analysis of C-banded chromosomes

The C-banded karyotypes of six Allium cepa cultivars, including five dry onions and one shallot, were investigated. Chromosome length and banding patterns were statistically analysed. The value of C-banding for distinguishing these Allium cepa cultivars was tested by the application of a discriminant analysis. It appeared that chromosomal differences between cultivars exist, but are too small to be clearly demonstrated with moderate efforts. Large variation within plants and between plants within cultivars, presumably for the greater part caused by the applied method, obscured the variation between the cultivars.

Evidence for eight tandem and five centric fusions in the evolution of the karyotype of Aethomys namaquensis A. Smith (Rodentia: Muridae).

G- and C-banded chromosomes of Aethomys namaquensis (2n = 24), A. chrysophilus (2n = 44), and Praomys coucha (2n = 36) are compared and contrasted with published material on Australian Muridae and North American Sigmodontidae. Direction and types of chromosomal rearrangements are established using cladistic methodology. An acrocentric morphology for chromosomes 5, 14, 15 and 20 (numbering system from Peromyscus) are proposed as primitive for the common ancestor of the Muridae and Sigmodontidae rodent lineages. Reduced diploid number of Aethomys namaquensis is derived by eight tandem and five centric fusions since divergence from the common ancestor with A. chrysophilus. The two species of Aethomys share one derived metacentric chromosome that distinguishes them from Praomys. Praomys has unique chromosomes which can be derived from the proposed primitive condition by five centric fusions and five pericentric inversions. It is concluded that karyotypic orthoselection for tandem and centric fusions is best explained by cellular or biochemical mechanisms rather than variation in population characteristics.

Amplification of repeated DNA sequences in wheat X rye hybrids regenerated from tissue culture

Previous C-banding analysis of wheat (Triticum aestivum)X rye (Secale cereale) hybrids regenerated from tissue culture revealed enlarged C-bands in some rye chromosomes, but the molecular nature of the change was not determined. In situ hybridization using two DNA probes containing repeated sequences from rye telomeric heterochromatin was conducted on these wheatX rye hybrids and their progeny to investigate the occurrence of amplification in repeated sequences. Clones pSC 74 and pSC 119, which contain sequences from the 480-bp and 120-bp repeated DNA families of rye, respectively, were used as probes. Amplification of 480-bp repeated sequences in the short arm telomere of chromosome 7R was detected in three wheatxrye hybrids and their progeny. The amplified 480-bp sequences were detected by an enlarged hybridization site for pSC 74 at the 7RS telomere, and by the appearance at this same telomeric site of an unlabeled, blue chromosome segment in an otherwise completely brown chromosome hybridizing entirely to the biotin-labeled pSC 119 probe. This variant form of chromosome 7R was not observed in several ‘Chaupon’ plants, or in the other hybrids derived from the same embryos, indicating the origin of the change in tissue culture. The amplified sequences were inherited up to at least three generations. Deletions and translocations were also observed.

C-banding patterns in the AustralianBulbine (Liliaceae): The annual group,B. semibarbata s. lato

Chromosome C-band patterns have been studied in 34 populations of the Australian annualBulbine group, which comprises 4x (2n = 26, 28), 8x (2n = 52, 54) and 12x (2n = 78) populations. The 2n = 26B. semibarbata populations have a simple, low heterochromatin pattern with very minor polytypic variation. The 2n = 28 populations, corresponding morphologically to a group given separate status asB. alata, are similar in pattern but exhibit pronounced enhancement of telomeric and, more particularly, centromeric dot bands. NOR heterochromatin and satellites are difficult to identify inB. alata but appear to occur in different positions from the 26-chromosome karyotype. Eastern Australian 8 x patterns are consistent with a proposed hybrid ancestry,B. semibarbata ×B. alata. Annual and perennial C-band profiles in the AustralianBulbine are discussed briefly in relation to the “additive” and “transformation” models of heterochromatin evolution and to the possible adaptive significance of variation in heterochromatin content.

Nuclear DNA variation in the genus Allium L. (Liliaceae)

4C nuclear DNA contents were determined for 42 Allium species, selected from all major taxonomic sections in the genus. Estimates of nuclear volumes were also made. A range of 4C DNA values from 41·19 pg to 142·78 pg was found, largely unrelated to basic chromosome number, polyploidy or taxonomic group, but correlated with flowering time. The results are discussed in relation to distribution of DNA values in the genus, proportions of chromosome C-banding, breeding systems and climatic adaptation.

DNA composition in South American camelids. I. Characterization and in situ hybridization of satellite DNA fractions.

The DNA composition and the in situ hybridization of satellite fractions were analysed in the New World camelids llama, alpaca, guanaco and vicuña. In the four camelid forms, it was possible to identify a similar main band DNA and five satellite fractions (I-V) with G + C base contents ranging from 32% to 66%. Satellites II-V from llama were in situ reannealed on chromosomes from the four camelid forms. The results obtained were: (a) the four satellites hybridized with regions of C-banding (centromeric regions of all chromosomes and short arms of some autosomes); (b) in general, homologous hybridizations (llama DNA versus llama chromosomes) were more efficient than heterologous reassociations; there were however three exceptions to this rule (vicuña and alpaca satellite fraction II, chromosome group B; vicuña fraction V, chromosome groups A and B); (c) X chromosomes from the four camelids had satellites III-V but lacked satellite II, (d) no satellite fraction was detected on chromosome Y. The analysis of the in situ hybridization patterns allowed to conclude that most or all C-banded chromosome regions comprise several satellite DNA fractions. It is, moreover, proposed that there is an ample interspecies variation in the number of chromosomes that cross-react with a given satellite fraction. Our data give further support to the close genomic kinship of New World camelids.

A cytogenetic characterization comparing a rat 6TG-resistant strain and 6TG-sensitive clones

A 8.3 μ/ml 6-thioguanine (6TG)-resistant strain was isolated from a rat tetraploid cell line by step-by-step selection in 6TG-medium. In the 6TG-resistant cell population 51% of the cells were tetraploid and 35% of the cells were hypertetraploid, i.e., one chromosome more than a tetraploid. The 6TG-resistant strain grew very well in RPMI 1640 medium with intervals of three days between subcultures. The 6TG-resistant cells all have a homogeneously staining region (HSRs) in one of the X chromosomes which do not stain after chromosome C-banding. They also possess a higher NORs activity and much lower frequency of sister chromatid exchanges (SCE). When the 6TG-resistant RCT cells were subcultured in 6TG-free medium for three days, their SCE frequency did not change. 5'-bromodeoxyuridine (BrdU) significantly suppressed the NORs activity for both 6TG-resistant cells and 6TG-sensitive cells (P<0.001).

G- and C-Banding Chromosomal Studies of Bats of the Family Emballonuridae

Extent and nature of chromosomal change among nine species representing six genera (Saccopteryx, Rhynchonycteris, Diclidurus, Balantiopteryx, Cormura, and Taphozous) were examined using data from G- and C-banded chromosomes. Heterochromatin was restricted to centromeric regions in most taxa; extensive additions of C-positive material occurred in Bal- antiopteryx and Cormura. Comparisons of G-bands of euchromatic arms revealed considerable variation in G-band pattern and imply extensive chromosomal evolution among emballonurid species. Outgroup comparisons of G-band karyotypes proposed as primitive for several families of bats failed to reveal conserved G-band patterns, thus limiting the usefulness of differentiall y stained chromosomal data for resolving phylogenetic relationships of the Emballonuridae. The karyotype of Cormura brevirostris includes an extraordinarily large X chromosome that is mostly euchromatic. Evolution of the X chromosome and the nature of the sex-determining system in Cormura are unclear, but the species appears to possess a unique sex chromosome mechanism.

Chromosomal alterations in the karyotype of triticale in comparison with the parental forms

Wheat chromosomes of the primary winter hexaploid and octoploid triticales and of the parental durum and common wheat varieties were studied using morphometric analysis. The size of some heterochromatic segments was shown to change in triticale. Telomeric and intercalary C-bands both increased and decreased in size whereas centromeric bands only increased. The size variability of C-bands in triticale B-genome chromosomes decreased in most of the cases and increased only for several specific C-bands. The C-bands of homologous B-genome chromosomes changed in the same direction in both triticale forms. The changes in size of the C-bands found in R-genome chromosomes detected earlier in these triticale forms (Badaeva et al. 1986) were shown to coincide in their pattern with the size changes of C-bands in homeological B-genome chromosomes. Our data are indicative of regular, directed chromosomal changes in the triticale karyotype.

Comparative study of G- and C-banded chromosomes of five species of Microtidae

G-banded karyotypes were compared in the following species of Microtidae: Microtus nivalis; M. cabrerae; M. arvalis and Arvicola sapidus. Previous observations on A. sapidus and A. terrestris (Diaz de la Guardia & Pretel, Caryologia 32: 183–189, 1979) were also incorporated in this study. The results show that Robertsonian translocations and pericentric inversions are common mechanisms involved in the karyotypic evolution of this group. Interspecific differences in C-banding patterns were also analyzed. Using the karyograph method (Imai et al., Am. Nat. 121: 477–488, 1983), the evolutionary distances of the karyotypes were estimated, and an attempt was made to establish a presumptive phylogenetic tree.

A study of karyotypes and heterochromatic associations in Artemia, with special reference to two N. Greek populations

The chromosomes of three stains of Artemia were studied, a bisexual diploid (A. franciscana, strain GSL), and two parthenogenetic tetraploids from Northern Greece. Routine karyotypes were constructed for the diploid and tetraploid forms, as well as a Giemsa C-banding karyotype of the bisexual form; some data are also presented on the chromosomal C-banding patterns of the parthenogenetic populations. The possible significance of various chromosomal configurations that have been observed, and their relationships to heterochromatin, are discussed.

Characterization of human chromosomal constitutive heterochromatin

The constitutive heterochromatin of human chromosomes is evaluated by various selective staining techniques, i.e., CBG, G-11, distamycin A plus 4,6-diamidino-2-phenylindole-2-HCl (DA/DAPI), the fluorochrome D287/170, and Giemsa staining following the treatments with restriction endonucleases AluI and HaeIII. It is suggested that the constitutive heterochromatin could be arbitrarily divided into at least seven types depending on the staining profiles expressed by different regions of C-bands. The pericentromeric C-bands of chromosomes 1, 5, 7, 9, 13-18, and 20-22 consist of more than one type of chromatin, of which chromosome 1 presents the highest degree of heterogeneity. Chromosomes 3 and 4 show relatively less consistent heterogeneous fractions in their C-bands. The C-bands of chromosomes 10, 19, and the Y do not have much heterogeneity but have characteristic patterns with other methods using restriction endonucleases. Chromosomes 2, 6, 8, 11, 12, and X have homogeneous bands stained by the CBG technique only. Among the chromosomes with smaller pericentric C-bands, chromosome 18 shows frequent heteromorphic variants for the size and position (inversions) of the AluI resistant fraction of C-band. The analysis of various types of heterochromatin with respect to specific satellite and nonsatellite DNA sequences suggest that the staining profiles are probably related to sequence diversity.

The heterochromatin of grasshoppers from the Caledia captiva species complex

A highly repeated family of sequences from the grasshopper Caledia captiva shows a dispersed distribution at the cytological level. Members of this 185 bp sequence family are not restricted to C-band heterochromatin, but rather are distributed in regions which appear as euchromatin in C-banded chromosomes. Sequence variation in this family is equivalent (14%–16%) at all levels of taxonomic comparison from within a population to between species. However, contiguous repeats demonstrate a much lower level of variation (9%). These, and other data, indicate that the concept of sequence “homogeneity” within a family of highly repeated sequences must be qualified with respect to the extensive variation between members of a given family. Comparison of the data for the 185 bp family with those from a study of a second highly repeated family, from the same taxon, demonstrates divergent patterns of evolution. Thus, the 185 bp repeats show much greater sequence variation, as well as a seemingly random pattern of incorporation of base pair alterations. The factors which may contribute to the observed pattern of variation include the time since the sequence family originated, its cytological distribution, the frequency of unequal crossing over and gene conversion and natural selection.

Chromosome alterations in the karyotype of triticale in comparison with the parental forms

R genome chromosomes were studied in two forms of primary triticales (hexaploid 'TPG-1/1-78' and octoploid 'AD 825') and in their parent rye forms (Secale cereale L. cv. 'Kharkovskaya 60' and 'VSKhI', respectively) using the methods of C-banding and morphometric analysis. The size of some heterochromatic segments was shown to alter in the karyotype of triticale. An increase in size was detected approximately in half of all telomeric C-bands; the size of the other C-bands either decreased or did not change. The frequencies of these alterations were 1∶1. The variability in the size of telomeric C-bands in rye chromosomes diminished in both triticales studied. The two triticale forms inherited variants of R genome chromosome polymorphism predominantly with the medium size range of telomeric C-bands. The centromeric C-bands in both triticale forms either enlarged or did not alter. Possible mechanisms responsible for the observed pattern of alterations are discussed.

Cytochemical heterogeneity of the C-band in human chromosome 1

The heterogeneity of the C-band of human chromosome 1 has been evaluated using several selective staining methods: C-banding (CBG), distamycin A plus 4-6-diamidino-2-phenylindole (DA/DAPI) and Giemsa G-11 pattern following the treatment with the restriction endonucleases AluI and HaeIII. The bands produced by each method are characteristic but not identical. The total C-band is resistant to AluI treatment. The bands induced by HaeIII and the one stained by DA/DAPI are markedly similar but smaller than the C-band. The G-11 technique stains yet smaller regions than those of HaeIII and DA/DAPI. Depending on the expression of staining properties, the C-band of chromosome 1 usually consists of three subdivisions: the proximal, intermediate and distal regions, suggesting an extremely heterogeneous nature. The staining variations between different regions are further substantiated by studies of a reciprocal translocation where the proximal region and the remaining C-band of chromosome 1 are separate.

Constitutive heterochromatin studies in patients with solid tumors.

Constitutive heterochromatin of chromosomes 1, 9, and 16 was studied in 101 patients with solid tumors and 85 controls. Lymphocyte cultures were used for performing C-banded chromosome preparations. Two homologous chromosomes were regarded as heteromorphic when there was a 25% difference between their C-band size or when they fell into different classes according to the method of Patil and Lubs (1977). A statistically significant difference between patients and controls was found in chromosome 1 heteromorphism. No statistical difference between patients and controls was found in the heteromorphism of chromosomes 9 and 16. The frequencies with which pericentric inversions of the heterochromatin in chromosomes 1 and 9 occurred in cancer patients were 9.9% and 12.9%, respectively. Patients displaying this type of polymorphism usually showed an increased rate of chromosome associations. The most frequent associations were found between heterochromatic regions of chromosomes 1 and 9 and between the chromosome 9 heterochromatin and D acrocentrics. These results support the hypothesis concerning the involvement of constitutive heterochromatin of chromosome 1 in malignant disease.

Relative DNA content of somatic nuclei and chromosomal studies in three genera,Tilapia, Sarotherodon, andOreochromis of the tribe Tilapiini (Pisces, Cichlidae)

Seven Tilapiine species from three generaTilapia, Sarotherodon, andOreochromis were cytogenetically studied for chromosome number, chromosome morphology, and DNA content. The chromosome number 2n=44 was the same in all seven species. Arm number (NF) differences indicate the possible role of pericentric invasions in the karyotypic evolution of these species. C-banding of metaphase chromosomes shows that heterochromatin is localised around the centromere in all species ofOreochromis and Sarotherodon butT. zillii has more heterochromatin with six chromosomes having completely C-positive short arms. DNA values vary between 0.84 pq forO. macrochir and 1.21 pq forO. aureus. No heteromorphic sex chromosome pair could be found in any species. These findings suggest that karyotypic evolution has occurred but does not appear to be associated with speciation in this group.

Cytogenetic markers in allogeneic bone marrow transplantation

Engraftment after bone marrow transplantation (BMT) can be monitored with genetic markers. Cytogenetic markers are the ones that can be studied earliest. Of 27 patients studied, 16 had a sex-mismatched donor, and in 8 cases, there were discriminative markers identified with regular Giemsa and Q-banding. In one case, there was a rather slight polymorphism of the C-bands of chromosomes #9. Thus, donors' cells were identifiable in 25 of 27 cases (93%). The markers studied easiest are the sex chromosomes #3 and characteristic satellites of acrocentric chromosomes are rather frequent and also well suited to discriminate donors' from patients' cells. Nonprominent variabilities (fluorescence of the centromeric regions of chromosomes #4 and #6 after Q-banding), rare polymorphisms (pericentric inversions of chromosomes #1 and #9), and difficult to evaluate polymorphisms (heterochromatic regions of chromosomes #1, #9, and #16) are not very practical for the routine monitoring of engraftment after BMT.

Cytosystematics of the South AfricanAethomys(Rodentia: Muridae)

The G-and C-band chromosome patterns and the location of the nucleolus organizer regions (NORs) are presented for A. namaquensis (2n = 24), A. granti (2n = 32) and A. chrysophilus (2n = 44; 2n = 50). The presence of two distinct cytotypes in what is conventionally recognized as A. chrysophilus is indicative of the presence of two discrete species which, karyology apart, appear to be indistinguishable using existing identification keys. The chromosomal relationships of the South African species and the taxonomic implications of these data are discussed.