Karyotype

About: Karyotype is a research topic. Over the lifetime, 16278 publications have been published within this topic receiving 416409 citations.

Comparison of different cytogenetic methods and tissue suitability for the study of chromosomes in Cimex lectularius (Heteroptera, Cimicidae).

Abstract: In the article we summarize the most common recent cytogenetic methods used in analysis of karyotypes in Heteroptera. We seek to show the pros and cons of the spreading method compared with the traditional squashing method. We discuss the suitability of gonad, midgut and embryo tissue in Cimex lectularius Linnaeus, 1758 chromosome research and production of figures of whole mitosis and meiosis, using the spreading method. The hotplate spreading technique has many advantages in comparison with the squashing technique. Chromosomal slides prepared from the testes tissue gave the best results, tissues of eggs and midgut epithelium are not suitable. Metaphase II is the only division phase in which sex chromosomes can be clearly distinguished. Chromosome number determination is easy during metaphase I and metaphase II. Spreading of gonad tissue is a suitable method for the cytogenetic analysis of holokinetic chromosomes of Cimex lectularius.

A high-resolution G-banding idiogram of Rattus norvegicus chromosomes.

Abstract: G-banded karyotypes of Rattus norvegicus fibroblast cells at the late prophase, prometaphase, early metaphase, mid and late metaphase, and diagrammatic representation of the banding patterns at the 450-band level are presented. High-resolution G-banded rat chromosomes were prepared following the actinomycin D pretreatment technique. Silver-stained nucleolus organizer regions (Ag-NORS) were found in chromosome pairs 3, 11 and 12 of the rat karyotype.

The Number of Chromosomes

Abstract: cross-infection experiments with R. Solani, and (6) a description of the growth of this fungus in various media. The numerous cross-infection experiments carried out with Rhizoctonia Solani are of special interest. Strains of the fungus from some 30 species of plants were used to infect carnations in several stages of growth, from the cutting to the mature plant, both under glass and in the field. A number of other plants also were infected with various strains of Rhizoctonia. The results of all these cross-infection experiments can best be stated in the author's own words: \"From these inoculation experiments with a large number of different types of plants, we must conclude that all the strains studied, which were obtained from a wide range of hosts of diverse geographical origin, can attack the same species of plant and produce the same characteristic symptoms. No marked specialization was noted in any of the strains. Thus, all the strains studied can be included under one form, Rhizoctonia Solani Kuhn. The inoculation experiments how further that the virulence of R. Solani is very variable, as is also the degree of resistance of the various host plants, both depending upon a number of factors.\" A study of the growth characteristics confirmed this general conclusion. Strains isolated from the same host species showed differences as great as those between strains isolated from different species. MATZ7 has described a form of Rhizoctonia occurring on the leaves and stems of Ficus Carica at Gainesville, Florida. This form is regarded by him as a distinct species, R. microsclerotia Matz. Aside from its foliicolous habit, it does not appear to differ essentially from R. Solani, which MATZ found was also capable of infecting fig leaves, without producing sclerotia, however. In a single experiment he fig fungus failed to infect seedlings of the cowpea, while R. Solani killed go per cent of the young plants.-H. HASSELBRING.

Characterization of a complex rearrangement involving chromosomes 1, 4 and 8 by FISH and array-CGH.

Abstract: Complex chromosomal rearrangements (CCRs) are structural aberrations involving more than two chromosomes with at least three breakpoints. CCRs can be divided into familial and de novo. Balanced CCR are extremely rare in humans and are at high risk of producing unbalanced gametes. Individuals with balanced CCR are usually phenotipically normal but report fertility problems, recurrent miscarriages or congenital anomalies in newborn offsprings as consequence of either meiotic failure or imbalanced chromosomes segregation.We describe the case of an unbalanced CCR involving chromosomes 1, 4 and 8 found in a girl with developmental delay, hexadactilia and microcephaly. The rearrangement, apparently balanced at a standard karyotype analysis and of maternal origin, was demonstrated to be unbalanced by array-CGH and FISH. In conclusion our study underlines the importance of the combined use of a quantitative technique, as array-CGH, to detect criptic segmental aneuploidies, and a qualitative tool, as FISH analysis, to physically map the localization of the chromosome segments involved, in order to realize the exact nature that underlies a chromosomal rearrangement.