An efficient protocol for chromosome isolation from sterlet (A. ruthenus) embryos and larvae

In the present study, the development of an efficient and feasible protocol for chromosome preparation from sterlet (A. ruthenus) embryos and larvae was carried out. In the established protocol, the mean efficiency of chromosome extraction ranged from 70 to 100%. The average number of recorded metaphases per slide was between 9 to 15. In general, the most satisfactory results were obtained for embryos at 6 dpf and larvae at the age of up to 7 dph. In the 24 dpf group, chromosome isolation was possible without immersion in spindle poison, however; in successive developmental stages, the minimal immersion time exceeded 1.5 hours, regardless of chorionation. Immersion for 14 hours did not compromise the efficacy of chromosome isolation. In the current study, successful chromosome isolation was determined mainly by hypotonization conditions. Younger developmental stages generally require the shortest hypotonization times, whereas older larvae require longer hypotonization times. The optimal hypotonization period is 5-15 minutes for embryos at 24 dpf, 40 minutes for embryos at 4dpf, and 50-60 minutes for fish at 6 dpf-7 dph. The only exception was the 24 hpf group where only blastula cells were used. An additional overnight fixation step significantly enhanced chromosome quality and supported chromosome counting especially in the 24 dpf group. The quality and quantity of chromosome slides were also significantly determined by tissue type, and the slides prepared from heads (gill cells) produced the best results.

Chromosome distribution between two restitution nuclei in a cell following colchicine treatment

Roots of Zea mays L., Secale cereale L., Vicia faba, L., Allium cepa L., and Hordeum vulgare L. were treated with colchicine. C-metaphases were observed in cells which had chromosomes present in two distinct groups, not the typical single group. Chromosome distribution into two groups was not followed by chromatid segregation: instead, the chromosomes underwent restitution and binucleate-interphase cells were formed. The distribution of chromosomes into two groups is functionally equivalent to chromosome nondisjunction. In some cases, the two groups contained different numbers of chromosomes; these gave rise to aneuploid nuclei. The results support the view that the pattern of chromosome distribution into two groups is not random; it may reflect chromosome position in the interphase or prophase nucleus. The results are related to (i) the formation of genotypic and phenotypic mosaics produced by treatment with other microtubule inhibiting drugs or in response to cell division mutants and (ii) the spatial distribution of chromosomes within the nucleus.

Clonal chromosome abnormalities in patients with Waldenstrom's and CLL- associated macroglobulinemia: significance of trisomy 12

We performed cytogenetic analyses by Q- and G-banding techniques of unstimulated or B-mitogen-stimulated spleen, bone marrow, and peripheral blood cells from six patients with malignant macroglobulinemia [two with Waldenstrom's macroglobulinemia (WM) and four with chronic lymphocytic leukemia associated macroglobulinemia (CLL-M)]. Normal karyotypes were obtained in two of the treated patients (one with WM in remission and the other with CLL-M in relapse). An extra chromosome 12 (trisomy 12) was observed in all four untreated patients. In patient no. 2 (K.R.) and no. 3 (F.G.) with CLL- M, an abnormal karyotype, with trisomy 12 as the only abnormality, was identified. In patient no. 1 (C.C.) with WM, there were two clonal chromosome changes, identified: 47, XX, -9, +12, plus marker chromosome and 48, XX, -9, +12, plus both marker and minute chromosomes. In patient no. 4 (R.M.) with CLL-M, a minute chromosome with or without loss of a G-group chromosome was seen in some metaphases without trisomy 12, in addition to metaphases with trisomy 12 alone. Each of the four untreated patients with WM or CLL-M had clonal chromosome abnormalities, suggesting that chromosome changes may be more frequently associated with WM or CLL-M than with typical CLL without macroglobulinemia. These observations also suggest that trisomy 12 may be the primary karyotypic change in malignant macroglobulinemia, whereas the appearance of the minute or marker chromosome as well as the loss of G-group chromosomes or chromosome no. 9 may be secondary karyotypic changes resulting from clonal evolution in these malignancies.

Clonal chromosome abnormalities in patients with Waldenstrom's and CLL- associated macroglobulinemia: significance of trisomy 12

We performed cytogenetic analyses by Q- and G-banding techniques of unstimulated or B-mitogen-stimulated spleen, bone marrow, and peripheral blood cells from six patients with malignant macroglobulinemia [two with Waldenstrom's macroglobulinemia (WM) and four with chronic lymphocytic leukemia associated macroglobulinemia (CLL-M)]. Normal karyotypes were obtained in two of the treated patients (one with WM in remission and the other with CLL-M in relapse). An extra chromosome 12 (trisomy 12) was observed in all four untreated patients. In patient no. 2 (K.R.) and no. 3 (F.G.) with CLL- M, an abnormal karyotype, with trisomy 12 as the only abnormality, was identified. In patient no. 1 (C.C.) with WM, there were two clonal chromosome changes, identified: 47, XX, -9, +12, plus marker chromosome and 48, XX, -9, +12, plus both marker and minute chromosomes. In patient no. 4 (R.M.) with CLL-M, a minute chromosome with or without loss of a G-group chromosome was seen in some metaphases without trisomy 12, in addition to metaphases with trisomy 12 alone. Each of the four untreated patients with WM or CLL-M had clonal chromosome abnormalities, suggesting that chromosome changes may be more frequently associated with WM or CLL-M than with typical CLL without macroglobulinemia. These observations also suggest that trisomy 12 may be the primary karyotypic change in malignant macroglobulinemia, whereas the appearance of the minute or marker chromosome as well as the loss of G-group chromosomes or chromosome no. 9 may be secondary karyotypic changes resulting from clonal evolution in these malignancies.