Interphase Nuclear Volume Research Articles

Interphase Nuclear Structure in Ten Species of Pteridophytes

In thelypterids, interphase chromosomes of Ampelopteris prolifera were accompanied by two or three nucleoli. One nucleolus was seen floating outside the nucleus while other remained attached with the nucleus in annular cells of Christella arida. The mean of chromocentres determined in Adiantum species ranged from 49.8 to 53.6, whereas, it ranged from 46.6 to 49.5 in Pteris species. On the other hand, the value for chromocentres ranged from 62.5 to 123.5 in thelypterids. Nuclear organization was observed to be chromocentric type. In case of interphase nuclear volume it was observed that in Adiantum it was highest in A. capillus-veneris followed by A. caudatum and A. lunulatum, in Pteris it was highest in P. biaurita followed by P. vittata and P. griffithi, and in case of thelypterids, it was highest in C. dantata followed by C. Cylindrothix, A. Prolifera and C. arida. J. Bio-Sci. 29(2): 93-98, 2021 (December)

Karyotype Variation in Eight Cultivars of Indian Dessert Banana (Musa acuminata L.) of Section Eumusa From Odisha, India

Banana (Musa spp.) cultivars especially dessert banana are important cash crop with high market demand all over the world as an integral part of the diet. The need for assessment of cytogenetic characters in Musa cultivars is inevitable as out of thousands of cultivars, cytogenetic characterization of most of them remains unresolved due to difficulties like small chromosome size, diversity in ploidy levels and high cultivar diversity which behave differently to standardized cytogenetic protocols. In this report, somatic chromosome number, detailed karyotype analysis including total chromosome length, volume, form percentage, Interphase Nuclear Volume (INV) were accessed on eight dessert type of Musa accessions from different places of Odisha. All the cultivars studied were found triploid (2n = 33) with a basic chromosome number of x=11. The karyotype formulae were assigned to each cultivar by grouping the chromosome according to their shared characteristics. The total chromosome length ranged from 54.95 µm in cv. Robusta to 81.5 µm in cv. Kathia with symmetric karyotype in all the studied cultivar. Karyotype formula revealed structural alteration of chromosome with Total Form percentage (TF%) variation from 35.65% in cv. Amritapani to 41.68% in cv. Patakpura that confirms more number of nearly median constricted chromosome as compared to sub-median chromosome. The total chromosome volume recorded from 10.78 µm3 in cv. Robusta to 15.99 µm3 in cv. Khatia and the INV varied from 1336.44 µm3 in cv. Dwarf Cavendish to 2048.37 µm3 in cv. Patakpura. The recorded structural variation might be due to differential genome specific condensation of chromosome. Chromosome length and volume found statistically significant among the cultivars.

Cytomorphologic parameters in monitoring cytogenotoxic effects of fertilizer in Allium cepa L.

The present investigation was done to assess cytomorphologic parameters as indicators of genotoxicity as it is a simpler method and could be suggested for rapid screening of the vast range of agrochemicals used all over the world. The excessive and indiscriminate use of agrochemicals is responsible for increasing the level of pollutants in the soil environment resulting in cellular and molecular damage to the plants. The cellular damage caused manifestation of the resulting oxidative stress due to pollutants which can go up to the level of DNA. The roots of Allium cepa were treated with 0.5mg Nml-1 concentration of ammonium nitrate fertilizer for 3, 6, 9 and 12h, and in mitotic preparation of their respective root, mitotic index, phase indices and the genotoxic markers viz. chromosomal aberrations and binucleate cells were observed and the data statistically analysed. A significant decrease in mitotic index and increase in abnormality percentage as compared to control was observed which increased with the treatment duration. Chromosomal aberrations like stickiness, fragmentation, precocious movement, bridges and disorientations were observed in varying frequencies. A cytomorphologic study revealed that the interphase cell volume of cells of treated roots and their respective interphase nuclear volume were reduced as compared to control. The ratio between nuclear and cytoplasmic volume has been reported to relate to cell integrity. Both these markers viz. cytomorphologic and genotoxic can be used for assessment of the toxicity of agrochemicals including fertilizer; in our study, they have revealed the cytogenotoxic behaviour of ammonium nitrate fertilizer.

Toxicity Bio-Monitoring of Shkodra Lake Surface Water Using a Higher Plant Assay

Health and quality of biota in natural ecosystems are directly affected by different kind of pollutants, accumulated because of uncontrolled releases into the environment of industrial effluents and urban waste, as well as by drainage, flooding, intensive farming and tourism. Bio-monitoring of Shkodra Lake water quality was done using Allium cepa L. assay. Bulbs were grown on surface water samples collected from six stations: S1-S3 at east and S4-S6 at west lake waterside, during August 2010-2013. The reaction of root meristematic tissue and its genetic material to the presence and quantity of potential cyto and genotoxic chemicals was done by evaluating macro and microscopic parameters, as: root length, mitotic and phase indexes, interphase nuclear volume, chromosome abnormalities frequency and types. The most toxic samples resulted 2011 and 2013 and the east waterside ones, which could be due to massive flooding during the respective years and the different trophy level between east and west lake basin sides. There were detected slight traces of toxic and persistent water chemical pollutants, serving as an alert of their possible bioaccumulation and negative impact on biota and human health. The A. cepa test could be successfully applied as a simple, short-term and inexpensive approach for environmental quality evaluation in developing areas and countries such as Shkodra region and Albania. DOI: 10.5901/ajis.2013.v2n8p133

Evaluation of genotoxic effects of five flavour enhancers (glutamates) on the root meristem cells of Allium cepa

The effects of different treatments with flavour enhancers monosodium glutamate, monopotassium glutamate, calcium diglutamate, monoammonium glutamate, and magnesium diglutamate on the cytology, DNA content, and interphase nuclear volume (INV) of A. cepa were investigated. Three concentrations of these additives - 20, 40, and 60ppm - were applied for 6, 12, and 24h. All the concentrations of these chemicals showed an inhibitory effect on cell division in root tips of A. cepa and caused a decrease in mitotic index values. Additionally, all the treatments changed the frequency of mitotic phases when compared with the control groups. These compounds increased chromosome abnormalities, among them are micronuclei, c-mitosis, anaphase bridges, stickiness, binucleus, laggards, and breaks. The nuclear DNA content and INV decreased when compared with control groups.

Cytotoxic and Genotoxic Potency Screening of Two Pesticides on Allium cepa L

The cyto- and genotoxicological potency of diclofop-methyl (herbicide) and lindane (insecticide) was screened using Allium cepa L. test. Onion roots were exposed for 24h to three doses, representing ¼, ½ and EC50 concentrations of each pesticide. Some microscopic endpoints as: mitotic and phase indexes, interphase nuclear volume and chromosomal aberration rate and types were evaluated. The results showed obvious concentration-dependence. Mitotic index decreased to 45-59% and 24-37%, while interphase nuclear volume was reduced to 49-54% and 36-42%, for diclofop-methyl and lindane respectively. Abnormal cell's frequency was considerably increased, too. Physiological and clastogenic types of chromosomal aberrations, as: stickiness, c-mitosis, c-anaphase, fragment and bridges, multipolarity and laggard chromosomes were observed in all corresponding concentrations. Data of this study showed that both analyzed pesticides (commonly used for decades in Albanian agriculture) can potentially induce cyto/genotoxic effect on crops and ultimately damage biota and human health.

Laser confocal microscopy analysis of human interphase nuclei by three-dimensional FISH reveals dynamic perinucleolar clustering of telomeres

Nuclear functions are strongly dependent on the three-dimensional organization of the interphase nucleus. Given the importance of telomeres in the behaviour and stability of chromosomes, we have investigated the architecture of the human nucleus from the telomere perspective by 3D-FISH and laser confocal microscopy. We observed a randomly scattered telomere distribution in all confocal sections of the interphase nuclear volume with various levels of telomere clustering in different cell types. This distribution is independent of H2AX presence or phosphorylation status. We also observed that telomeres usually cluster at the periphery of the nucleolus following its cell cycle dependent dynamic formation but are never present in the interior of the nucleolus. These perinucleolar telomeric clusters contain the telomeres of the short arms of acrocentric chromosomes, explaining the p-arm association of acrocentric chromosomes frequently found in metaphase. Thus, chromosome positioning in metaphase spreads is tightly connected to the three-dimensional architecture of the interphase nucleus.

Genotoxic effects of mono-, di-, and trisodium phosphate on mitotic activity, DNA content, and nuclear volume inAllium cepaL.

Abstract The effects of the food additives monosodium phosphate (MSP), disodium phosphate (DSP) and trisodium phosphate (TSP) have been studied on root tips of Allium cepa L. Roots of A. cepa were treated with a series of concentrations, ranging from 300 to 500 ppm for 24, 48 and 72 h. The results indicated that these food preservatives reduced mitotic division in A. cepa when compared with the respective control. Mitotic index values were generally decreased with increasing concentrations and longer treatment times. Additionally, variations in the percentage of mitotic stages were observed. The total percentage of aberrations generally increased with increasing concentrations of these chemicals and longer period of treatment. Different abnormal mitotic fgures were observed in all mitotic phases. Among these abnormalities were stickiness, anaphase bridges, C-mitosis and micronuclei. These food additives remarkably depressed the DNA content in the root meristems of A. cepa. The interphase nuclear volume (I...

Preliminary study on genetic relationships of Melocactus Link & Otto of the family Cactaceae revealed through karyotype, DNA content and RAPD analysis

The genetic relationships of 10 species of Melocactus was determined using karyotype, Interphase Nu- clear Volume (INV), 4C DNA content and RAPD markers. Somatic chromosome number varied from 2n=22 to 2n=44. Detailed karyotype analysis showed interspecific variation along with structural alteration of chromosomes. Significant variation in INV and nuclear DNA content were noted among the species. DNA content per chromo- some varied from 0.812pg in M. ernestii (2n=44) to 1.13pg. in M. bahiensis (2n=22). Interspecific RAPD polymor- phism varied from 42.85% in between M. bahiensis and M. ernestii to 75.60% in between M. zehntneri and M. ernestii ssp ernestii. Phylogenetic tree obtained from RAPD markers revealed M. curvispinus as an original species of the group with a wide assemblage of M. peruvianus, M. bahiensis ssp bahiensis f. acispinosus and M. zehntneri. M. bahiensis ssp bahiensis f. acispinosus claimed as separate species and separated out from M. oreas group as well as M. zehntneri from M. violaceus group. Close genetic homology among M. ernestii ssp ernestii, M. ernestii, and M. matanzanus confirmed the right placement of these species in M. oreas group where M. ernestii ssp ernestii could be considered as a species. Distant affinity of M. bahaensis with M. ernestii under a same group confirmed its right position in M. oreas group. M. concinnus with the M. ernestii and M. bahiensis forming a separate distinct branch of the tree confirm its origin from a same ancestor and disagree with its placement in M. violaceus.

Variation in Chromosome Number, Karyotype and Nuclear DNA Content of Five Species of Indian Typhonium Schott. (Araceae)-A Medicinally Important Plant

Detailed karyotype analysis of somatic chromosomes in 5 species of Typhonium Schott. of the family Araceae was carried out for the first time. The chromosome number varied from 2n=16 in T. flagelliforme to 2n=52 in T. diversifollium. Chromosome number 2n=18 and 2n=26 in T. trilobatum and T. roxburghii respectively suggest formation of anueploids during speciation. The asymmetric karyotype revealed structural alterations with 2 distinct types of chromosomes (long and very short types) as evident in different species of Typhonium. Significant variations in chromosome size were observed among the studied species. TF% revealed sub-metacentric long chromosomes in T. flagelliforme (TF value, 33%) and metacentric short chromosomes in T. diversifolium (TF value, 41%). Average chromosome length varied from 2.03 μm in T. diversifolium, a high altitude species (5000–7000 ft), to 8.68 μm in T. flagelliforme, a low land species (70–250 ft). Significant variations were observed in Interphase Nuclear Volume (INV) which varied from 142.05 μm3 in T. trilobatum to 335.02 μm3 in T. flagelliforme; nuclear DNA content varied significantly from 0.199 pg in T. diversifolium to 0.833 pg in T. flagelliforme.

Effect of a low dose of aluminum on mitotic and meiotic activity, 4C DNA content, and pollen sterility in rice, Oryza sativa L. cv. Lalat

Aluminum toxicity in acidic soils poses a major threat to plant growth and development. The effects of a low dose of aluminum (50 μM, AlCl 3) on various cytological parameters, including mitotic and meiotic chromosomal divisions, in situ nuclear DNA content, interphase nuclear volume (INV), and pollen fertility were compared in untreated (controls) and treated rice plants ( Oryza sativa cv. Lalat). The results showed varied chromosomal abnormalities, including chromosome stickiness, laggards, sticky bridge, occurrence of micronuclei, as well as binucleate and multinucleated cells, as a result of aluminum treatment. Aluminum toxicity also inhibited to a small extent the growth of the rice cultivar Lalat. The mitotic and meiotic indexes, even after a prolonged period of recovery, were significantly low. The chromosomal anomalies in the meiotic cells persisted, and plants exhibited a high percentage of pollen sterility (∼64%). The nuclear DNA content declined markedly from 11.85 pg in the control to 6.30 pg in the treated plants. The INV also varied significantly between the untreated (controls) and the treated plants. The occurrences of different types of chromosomal aberrations, reduction in the amount of nuclear DNA, and persistence of the phytotoxic effects at the post-treatment stage suggest carcinogenic effects of aluminum on rice plants. The presence of aluminum in acidic soils might thus be extremely hazardous and might cause permanent cytotoxic disorder in rice plants.

New reports of chromosome number and genome size in eight mangroves from coastal Orissa

Abstract Detailed karyotype analysis and cytophotometric estimation of 4C DNA amount as well as inter-phase nuclear volume (INV) were carried out in eight mangrove associates found in Bhitarkanika mangrove forest of coastal Orissa, India. Somatic chromosome number of Sarcolobus carinatus (2n=22), Lumnitzera racemosa (2n=24), Tylophora tenuis (2n=24), Sphaeranthus indicus (2n=30), Cerbera manghas (2n=40), Sesuvium portulacastrum (2n=48), Syzygium cumini (2n=66), and Hibiscus tiliaceous (2n=86) were recorded for the first time. Karyotype analysis revealed numerical and structural alterations of somatic chromosomes in different species. Significant variations of 4C DNA content was noted among the species ranged from 5.31pg in T. tenuis to 27.83pg in C. manghas. Genome size varied about five fold among the taxon of different familiesfrom 1301 Mbp in T. tenuis to 6818 Mbp in C. manghas. Chromosome length, volume and INV showed significant correlation between them. ANOVA analysis confirmed the variation in nucl...

Karyotype Variation and Cytophotometric Estimation of In Situ DNA Content in Some Minor and Associate Mangroves of India.

Detailed karyotype analysis and cytophotometric estimation of in situ 4C nuclear DNA amount as well as interphase nuclear volume (INV) were carried out in Aegialitis rotundifolia, Suaeda nudiflora and Thespesia populnea found in the mangrove forests of Orissa, India. Somatic chromosome number 2n=26, 34 and 54 were noted in T. populnea, A. rotundifolia, S. nudiflora respectively. Karyotype analysis revealed numerical variations and minute structural alterations of somatic chromosomes in different species. Critical analysis of nuclear DNA also showed significant variations in the 4C DNA content. S. nudiflora, a mangrove associate, showed variations at the ploidy level in root meristematic cells suggesting existence of cytotypes in the natural population. Significant correlation was found between chromosome length, volume and 4C DNA content.

Interspecific Variations of Nuclear DNA Content and Karyotype Diversity in Ferocactus.

Karyotype analysis, determination of somatic chromosome number, total chromosome length and volume, cytophotometric estimation of 4C DNA content and Interphase Nuclear Volume (INV) were carried out in 6 species of Ferocactus of the family Cactaceae. Significant interspecific variations in nuclear DNA amount were noted with a constant somatic chromosome number (2n=22). The 4C DNA content varied from 7.04 pg in F. horridus to 9.20 pg in F. wislizeni. The INV varied from 330.22 μm3 in F. latispinus to 482.36 μm3 in F. wislizeni. The 4C DNA content showed a significant positive correlation with both mean chromosome volume and INV; mean chromosome volume also showed a significant correlation with mean INV. The structural alterations in the chromosomes as well as loss or addition of highly repetitive sequences in the genome suggest variations in the nuclear DNA at interspecific level during macro- and micro-evolution of the species.

The distribution of polycomb-group proteins during cell division and development in Drosophila embryos: impact on models for silencing.

The subcellular three-dimensional distribution of three polycomb-group (PcG) proteins-polycomb, polyhomeotic and posterior sex combs-in fixed whole-mount Drosophila embryos was analyzed by multicolor confocal fluorescence microscopy. All three proteins are localized in complex patterns of 100 or more loci throughout most of the interphase nuclear volume. The rather narrow distribution of the protein intensities in the vast majority of loci argues against a PcG-mediated sequestration of repressed target genes by aggregation into subnuclear domains. In contrast to the case for PEV repression (Csink, A.K., and S. Henikoff. 1996. Nature. 381:529-531), there is a lack of correlation between the occurrence of PcG proteins and high concentrations of DNA, demonstrating that the silenced genes are not targeted to heterochromatic regions within the nucleus. There is a clear distinction between sites of transcription in the nucleus and sites of PcG binding, supporting the assumption that most PcG binding loci are sites of repressive complexes. Although the PcG proteins maintain tissue-specific repression for up to 14 cell generations, the proteins studied here visibly dissociate from the chromatin during mitosis, and disperse into the cytoplasm in a differential manner. Quantitation of the fluorescence intensities in the whole mount embryos demonstrate that the dissociated proteins are present in the cytoplasm. We determined that <2% of PH remains attached to late metaphase and anaphase chromosomes. Each of the three proteins that were studied has a different rate and extent of dissociation at prophase and reassociation at telophase. These observations have important implications for models of the mechanism and maintenance of PcG- mediated gene repression.

Variation in Karyotype and 4C DNA Content in Six Species of Melocactus of the Family Cactaceae.

Analysis of karyotype including somatic chromosome number determination, total chromosome length and volume, estimation of 4C DNA content and Interphase Nuclear Volume (INV) were carried out in 6 species of Melocactus of the family Cactaceae. Somatic chromosome number recorded 2n=22 in Melocactus bahiensis, M curvispinus, M robustispinus, M. townsendii and 2n=44 in M longispinus, M. matanzanus for the first time. Significant interspecific variation in nuclear DNA amount was recorded. The 4C DNA content varied from 20.55 pg in M. townsendii to 40.80 pg in M. longispinus. The correlation coefficient studies showed that the genomic chromosome length, chromosome volume and INV were possitively correlated. No interdependent was found between 4C DNA content and chromosome length or volume and INV. The structural alterations in the chromosomes as well as loss or addition of highly repetitive sequences in the genome showed variations in nuclear DNA at interspecific level indicating a macro- and micro-evolution of the species.

Interspecific variation of nuclear DNA and structural changes in meiotic and mitotic chromosome in some species of Mammillaria (Cactaceae)

Mitotic and meiotic chromosome number, karyotype, chiasma frequency in pollen mother cells, Interphase Nuclear Volume (INV) and nuclear DNA amounts in 12 species of Mammillaria revealed significant...

Karyotype diversity and interspecific 4C DNA variation inBupleurum

Investigation on karyotype, 4C nuclear DNA amount and interphase nuclear volume (INV) of different HimalayanBupleurum species belonging toUmbelliferae revealed genetic differentiation. Numerical and structural alternation of chromosomes in interspecific level were manifested in their statistically significant altered species specific 4C nuclear DNA content. Somatic chromosome number ranged between 2n = 14 and 2n = 16.B. himalayense was reported for the first time having 2n = 16 chromosomes. Correlation coefficient among the various chromosomal and nuclear parameters showed no significant progressive or regressive interdependence except in between INV and nuclear DNA amount. Critical differences between 4C DNA content showed interspecific variation.

Different replication patterns of chromocentres and C-bands inLilium henryi

To determine if interphase chromocentres are fully equivalent to mitotic C-bands in plants, their times of replication have been compared in the large genome (1C=35 pg) ofLilium henryi. Nuclei of the root-tip cortex were pulse labelled with3H-thymidine and labelling patterns carefully followed in semi-thin sections during a 12 h chase period. Chromocentres decondense and replicate in the later stages of S-phase, after euchromatin has completed its replication. Late-replicating regions, reflecting a portion of the chromocentric material, were then mapped in mitotic chromosomes and found to be localized to the sub-distal and distal regions of all long chromosome arms. Most of the chromatin in these regions is non C-banded and, further, not all C-bands are located here. Some of the 11 inter-calary and 2 nucleolar C-bands are found in earlier replicating regions, as are the 12 centric bands. ThereforeLilium C-bands do not all replicate at the end of S-phase. Chromocentres occupy 17–18% of interphase nuclear volume while C-bands make up only 3.7% of the area of mitotic chromosomes. We conclude thatLilium chromocentres contain much other chromatin in addition to C-bands, and therefore that chromocentres and C-bands cannot be universally equated.

Heterogeneity of Meristematic Cells ofVicia Faba: Evidence from Nuclear and Chromosome Volumes and from Nuclear Protein Content

SUMMARYNuclear volumes and the frequencies of nuclei of different shape classes were determined, in cells in interphase and in prophase, in meristems of young and old primary roots, of long lateral roots and of small primordia of Vicia faba. Protein content of isolated nuclei of lateral roots was also determined. Lateral roots were treated with 0.0002% colchicine for two hours and volumes of metaphase chromosome complements were determined. The parameters measured all showed considerable variation: 1) interphase nuclear volumes covered an 8-fold range in old primaries and a 14-fold range in lateral roots; 2) nuclear protein contents showed a 5-fold spread of values; 3) prophase nuclear volumes showed a 4 to 7-fold range of values; 4) chromosome volumes covered a 5-fold range. Nuclear volumes, in most cases, were significantly different from a linear or a log normal distribution. Nevertheless, these values, on probit plots, did not fall into discrete sub-populations and we were unable to distinguish betwee...