scholarly journals Nuclear morphology, polyploidy, and chromatin elimination in tissue culture of Allium fistulosum L.

2011 ◽  
Vol 72 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Andrzej Joachimiak ◽  
Tomasz Ilnicki

<p>The morphology of cell nuclei in callus obtained from root-tip meristems of <em>Allium fistulosum</em> L. (Monocotyledoneae, Alliaceae) was analysed. The most interesting phenomena observed in long-term callus culture were the different mechanisms of cell polyploidization, enlargement of telomeric segments of heterochromatin, and extensive chromatin elimination, associated with instability of nuclei size and DNA content.</p><p>Protruding heterochromatin "spikes" were observed on the surface of some di- and polyploid nuclei. The presence of these spikes was connected with the formation of small heterochromatic micronuclei frequently found in the cytoplasm. It is suggested that these micronuclei are produced by direct elimination of heterochromatin from the interphase nuclei.</p><p>Polyploid cells accumulated with each successive cell collection. The ploidy level attained by highly polyploid cells was 15C-220C. The shape of the nuclei and heterochromatin distribution suggest that polyploid nuclei in <em>A. fistulosum</em> tissue culture are produced by endoreduplication and by restitution cycles.</p>

1989 ◽  
Vol 65 (4) ◽  
pp. 1125-1135 ◽  
Author(s):  
J G De Mey ◽  
M P Uitendaal ◽  
H C Boonen ◽  
M J Vrijdag ◽  
M J Daemen ◽  
...  

Laboratory organization involves both the physical establishment and its operation. It is perhaps simplest to divide the laboratory into its component sections and discuss each separately. The areas may physically overlap for a small facility, and depending on the operation specialty, some sections, such as tissue culture or probe amplification, may not be required. Unless the operation is large, dark room and cold room facilities and expensive equipment such as an ultracentrifuge and beta counter are best shared, if feasible. The setup of a DNA analysis facility is a relatively simple process if it is incorporated into an established biochemistry program; it is considerably more involved if no such base exists. The outline presented in this chapter is only a guide; individuals contemplating the development of a new facility should visit as many established centers as possible. Discussions with sales representatives and attendance at relevant trade shows and DNA conferences are invaluable. Office requirements for a DNA program are no different in principle from those of any other biochemistry program. At least one separate office is required, usually for the program director and, as space permits, offices for a clerk-secretary and senior technologist are useful. Everyone working in the laboratory must have at least a small partitioned desk space in a quiet location. Lockable fire-resistant cabinets are required to store sensitive records; these cabinets should be accessible, preferably located in the clerical area. Analysis results are worthless without proper documentation of a specimen’s chain of custody (continuity). Information, including time and conditions of specimen procurement, conditions of storage and shipment, date received by the laboratory, and reason for the analysis request is also required. These data can be manually recorded; however, entry into a computer program capable of sorting and maintaining records for long-term retrieval is almost mandatory. Storage of unprocessed specimens may be necessary, and if at all possible, DNA should be isolated when received.


HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 439D-439 ◽  
Author(s):  
Mary Ann Start ◽  
James Luby ◽  
Robert Guthrie ◽  
Debby Filler

The hardy Actinidia species represent a source of genetic diversity for improving A. deliciosa (kiwifruit) as well as for creating new economically important cultivars through intra- and interspecific crosses. Attempts at breeding in Actinidia have been complicated by the existence of intraspecific as well as interspecific variation in ploidy. The haploid chromosome number in Actinidia is 29 and diploid (2n=2x=58), tetraploid (2n=4x=116), and hexaploid (2n=6x=174) levels have been identified. Because of the problems encountered when crossing parents differing in ploidy level, it is desirable to know the ploidy levels of plants to be used in breeding. We determined the ploidy levels of 61 Actinidia accessions currently available in the U.S., including primarily accessions of relatively winter-hardy species. The 61 accessions, representing eight species and three interspecific hybrids, were screened for ploidy using flow cytometry. Mitotic root tip cells from one plant from each putative ploidy level were examined microscopically to confirm the ploidy level derived from flow cytometry. There were 17 diploids, 40 tetraploids, and 4 hexaploids. Intraspecific variation was not found among accessions of the species arguta, callosa, deliciosa, kolomikta, melanandra, polygama, or purpurea. All kolomikta and polygama accessions were diploid. All arguta, callosa, melanandra, and purpurea accessions were tetraploid. Actinidia deliciosa was hexaploid. One chinensis accession was tetraploid. Two accessions (NGPR 0021.14 and 0021.3), acquired as chinensis, were hexaploid and may, in fact, be A. deliciosa based on their morphology. `Issai' (arguta × polygama) was hexaploid and `Ken's Red' and `Red Princess' (both melanandra × arguta) were tetraploid.


1956 ◽  
Vol 63 (1) ◽  
pp. 52-58
Author(s):  
VERNON P. PERRY ◽  
VIRGINIA J. EVANS ◽  
WILTON R. EARLE ◽  
GEORGE W. HYATT ◽  
WALLACE C. BEDELL
Keyword(s):  

1996 ◽  
Vol 109 (4) ◽  
pp. 773-776 ◽  
Author(s):  
A.C. Chandley ◽  
R.M. Speed ◽  
A.R. Leitch

Using whole chromosome painting probes for human chromosomes 3,7,8,13,17 and 21 and X and the probe pHY2.1 for the Y chromosome coupled with fluorescent in situ hybridization (FISH) analysis, the distribution of chromosomes is reported in nuclei of Sertoli cells of the adult testis and in stimulated blood lymphocytes. The distribution of chromosomes in the two cell types is significantly different. A strong tendency for each pair of homologues to pair is inferred from the observation of only a single detectable signal in the majority of Sertoli cell nuclei. The sex chromosomes, by contrast, give two clearly separated signals. Interphase nuclei in dividing blood lymphocytes, analysed as controls, also show mainly two separated signals for all non-acrocentric autosomal pairs, but acrocentric pairs no. 13 and 21 show some tendency to associate, probably reflecting satellite association.


1990 ◽  
Vol 95 (3) ◽  
pp. 335-341
Author(s):  
A.R. Leitch ◽  
W. Mosgoller ◽  
T. Schwarzacher ◽  
M.D. Bennett ◽  
J.S. Heslop-Harrison

In situ hybridization using biotinylated total genomic DNA and avidin detection systems was adapted for examination of thin-sectioned plant material in the light and electron microscopes. Root tip material was preserved prior to sectioning, so that the in vivo disposition of the chromatin was maintained. Use of total genomic DNA from Secale africanum as a probe enabled the chromatin from the two parental genomes in the grass hybrid Hordeum chilense × S. africanum to be distinguished. The biotinylated probe preferentially labelled the chromosomes of S. africanum origin. DNA-DNA hybrids were visualized at the light-microscope level by Texas Red fluorescence and at the electron-microscope level by the enzymic precipitation of DAB (diaminobenzidine) or by colloidal gold particles. The use of thin sections allowed the location of probe hybridization to be established unequivocally in both metaphase and interphase nuclei. Analysis of interphase nuclei showed that chromatin originating from the two parental genomes did not intermix but occupied distinct domains.


Plants ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 929
Author(s):  
Carloalberto Petti

Tissue culture is an essential requirement in plant science to preserve genetic resources and to expand naturally occurring germplasm. A variety of naturally occurring and synthetic hormones are available to induce the processes of dedifferentiation and redifferentiation. Not all plant material is susceptible to tissue culture, and often complex media and hormone requirements are needed to achieve successful plant propagations. The availability of new hormones or chemicals acting as hormones are critical to the expansion of tissue culture potentials. Phloroglucinol has been shown to have certain hormone-like properties in a variety of studies. Ornithogalum dubium, an important geophyte species, was used to characterise the potential of phloroglucinol as the sole plant-like hormone in a tissue culture experiment. Tissue culture, plant regeneration, total phenolic and genetic variability were established by applying a variety of methods throughout long-term experiments. Phloroglucinol did induce callus formation and plant regeneration when used as the sole supplement in the media at a rate of 37%, thus demonstrating auxin/cytokines-like properties. Callus formation was of 3 types, friable and cellular, hard and compact, and a mixture of the two. The important finding was that direct somatogenesis did occur albeit more frequently on younger tissue, whereby rates of induction were up to 52%. It is concluded that phloroglucinol acts as a “hormone-like” molecule and can trigger direct embryogenesis without callus formation.


2005 ◽  
Vol 141 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Martin Marsala ◽  
Osamu Kakinohana ◽  
Michael P. Hefferan ◽  
Dasa Cizkova ◽  
Kiyohiko Kinjoh ◽  
...  

Blood ◽  
1997 ◽  
Vol 89 (12) ◽  
pp. 4537-4545 ◽  
Author(s):  
S. Kozubek ◽  
E. Lukášová ◽  
L. Rýznar ◽  
M. Kozubek ◽  
A. Lišková ◽  
...  

Abstract Using dual-color fluorescence in situ hybridization (FISH) combined with two-dimensional (2D) image analysis, the locations of ABL and BCR genes in cell nuclei were studied. The center of nucleus-to-gene and mutual distances of ABL and BCR genes in interphase nuclei of nonstimulated and stimulated lymphocytes as well as in lymphocytes stimulated after irradiation were determined. We found that, after stimulation, the ABL and BCR genes move towards the membrane, their mutual distances increase, and the shortest distance between heterologous ABL and BCR genes increases. The distribution of the shortest distances between ABL and BCR genes in the G0 phase of lymphocytes corresponds to the theoretical distribution calculated by the Monte-Carlo simulation. Interestingly, the shortest ABL-BCR distances in G1 and S(G2 ) nuclei are greater in experiment as compared with theory. This result suggests the existence of a certain regularity in the gene arrangement in the G1 and S(G2 ) nuclei that keeps ABL and BCR genes at longer than random distances. On the other hand, in about 2% to 8% of lymphocytes, the ABL and BCR genes are very close to each other (the distance is less than ∼0.2 to 0.3 μm). For comparison, we studied another pair of genes, c-MYC and IgH, that are critical for the induction of t(8; 14) translocation that occurs in the Burkitt's lymphoma. We found that in about 8% of lymphocytes, c-MYC and IgH are very close to each other. Similar results were obtained for human fibroblasts. γ-Radiation leads to substantial changes in the chromatin structure of stimulated lymphocytes: ABL and BCR genes are shifted to the nuclear center, and mutual ABL-BCR distances become much shorter in the G1 and S(G2 ) nuclei. Therefore, we hypothesize that the changes of chromatin structure in the irradiated lymphocytes might increase the probability of a translocation during G1 and S(G2 ) stages of the cell cycle. The fact that the genes involved in the t(8; 14) translocation are also located close together in a certain fraction of cells substantiates the hypothesis that physical distance plays an important role in the processes leading to the translocations that are responsible for oncogenic transformation of cells.


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