Genetic and epigenetic instability of amplification-prone sequences of a novel B chromosome induced by tissue culture in Plantago lagopus L.

2009 ◽  
Vol 28 (12) ◽  
pp. 1857-1867 ◽  
Author(s):  
Gurmeet Kour ◽  
Balbir Kour ◽  
Sanjana Kaul ◽  
Manoj Kumar Dhar
Keyword(s):  
Tissue Culture ◽  
B Chromosome ◽  
Epigenetic Instability ◽  
Plantago Lagopus

scholarly journals B chromosome in Plantago lagopus Linnaeus, 1753 shows preferential transmission and accumulation through unusual processes

2017 ◽  
Vol 11 (2) ◽  
pp. 375-392 ◽  
Author(s):  
Manoj K. Dhar ◽  
Gurmeet Kour ◽  
Sanjana Kaul
Keyword(s):  
B Chromosome ◽  
Unreduced Gametes ◽  
Molecular Techniques ◽  
Root Tip ◽  
Genetic Constitution ◽  
Preferential Transmission ◽  
Female Sex ◽  
Process Formation ◽  
Plantago Lagopus ◽  
Mother Cells

Plantagolagopus is a diploid (2n = 2x =12) weed belonging to family Plantaginaceae. We reported a novel B chromosome in this species composed of 5S and 45S ribosomal DNA and other repetitive elements. In the present work, presence of B chromosome(s) was confirmed through FISH on root tip and pollen mother cells. Several experiments were done to determine the transmission of B chromosome through male and female sex tracks. Progenies derived from the reciprocal crosses between plants with (1B) and without (0B) B chromosomes were studied. The frequency of B chromosome bearing plants was significantly higher than expected, in the progeny of 1B female × 0B male. Thus, the B chromosome seems to have preferential transmission through the female sex track, which may be due to meiotic drive. One of the most intriguing aspects of the present study was the recovery of plants having more chromosomes than the standard complement of 12 chromosomes. Such plants were isolated from the progenies of B chromosome carrying plants. The origin of these plants can be explained on the basis of a two step process; formation of unreduced gametes in 1B plants and fusion of unreduced gametes with the normal gametes or other unreduced gametes. Several molecular techniques were used which unequivocally confirmed similar genetic constitution of 1B (parent) and plants with higher number of chromosomes.

scholarly journals B chromosome in Plantago lagopus Linnaeus, 1753 shows preferential transmission and accumulation through unusual processes

2017 ◽  
Vol 11 (2) ◽  
pp. 375-392
Author(s):  
Manoj K. Dhar ◽  
Gurmeet Kour ◽  
Sanjana Kaul
Keyword(s):  
B Chromosome ◽  
Unreduced Gametes ◽  
Molecular Techniques ◽  
Root Tip ◽  
Genetic Constitution ◽  
Preferential Transmission ◽  
Female Sex ◽  
Process Formation ◽  
Plantago Lagopus ◽  
Mother Cells

Plantagolagopus is a diploid (2n = 2x =12) weed belonging to family Plantaginaceae. We reported a novel B chromosome in this species composed of 5S and 45S ribosomal DNA and other repetitive elements. In the present work, presence of B chromosome(s) was confirmed through FISH on root tip and pollen mother cells. Several experiments were done to determine the transmission of B chromosome through male and female sex tracks. Progenies derived from the reciprocal crosses between plants with (1B) and without (0B) B chromosomes were studied. The frequency of B chromosome bearing plants was significantly higher than expected, in the progeny of 1B female × 0B male. Thus, the B chromosome seems to have preferential transmission through the female sex track, which may be due to meiotic drive. One of the most intriguing aspects of the present study was the recovery of plants having more chromosomes than the standard complement of 12 chromosomes. Such plants were isolated from the progenies of B chromosome carrying plants. The origin of these plants can be explained on the basis of a two step process; formation of unreduced gametes in 1B plants and fusion of unreduced gametes with the normal gametes or other unreduced gametes. Several molecular techniques were used which unequivocally confirmed similar genetic constitution of 1B (parent) and plants with higher number of chromosomes.

scholarly journals Origin, Behaviour, and Transmission of B Chromosome with Special Reference to Plantago lagopus

Genes ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 152 ◽  
Author(s):  
Manoj Dhar ◽  
Jasmeet Kour ◽  
Sanjana Kaul
Keyword(s):  
Ribosomal Dna ◽  
Dna Sequences ◽  
B Chromosome ◽  
Repetitive Elements ◽  
B Chromosomes ◽  
Current Status ◽  
Sequencing Data ◽  
Molecular Cytogenetic Techniques ◽  
Plantago Lagopus ◽  
Eukaryotic Organisms

B chromosomes have been reported in many eukaryotic organisms. These chromosomes occur in addition to the standard complement of a species. Bs do not pair with any of the A chromosomes and they have generally been considered to be non-essential and genetically inert. However, due to tremendous advancements in the technologies, the molecular composition of B chromosomes has been determined. The sequencing data has revealed that B chromosomes have originated from A chromosomes and they are rich in repetitive elements. In our laboratory, a novel B chromosome was discovered in Plantago lagopus. Using molecular cytogenetic techniques, the B chromosome was found to be composed of ribosomal DNA sequences. However, further characterization of the chromosome using next generation sequencing (NGS) etc. revealed that the B chromosome is a mosaic of sequences derived from A chromosomes, 5S ribosomal DNA (rDNA), 45S rDNA, and various types of repetitive elements. The transmission of B chromosome through the female sex track did not follow the Mendelian principles. The chromosome was found to have drive due to which it was perpetuating in populations. The present paper attempts to summarize the information on nature, transmission, and origin of B chromosomes, particularly the current status of our knowledge in P. lagopus.

Plantago lagopus B Chromosome Is Enriched in 5S rDNA-Derived Satellite DNA

2016 ◽  
Vol 148 (1) ◽  
pp. 68-73 ◽  
Author(s):  
Katrin Kumke ◽  
Jiří Macas ◽  
Jörg Fuchs ◽  
Lothar Altschmied ◽  
Jasmeet Kour ◽  
...  
Keyword(s):  
Repetitive Sequences ◽  
Nuclear Genome ◽  
5S Rdna ◽  
B Chromosome ◽  
B Chromosomes ◽  
Specific Marker ◽  
Sequencing Technology ◽  
Plantago Lagopus ◽  
Copy Dna ◽  
Chromosome Segments

B chromosomes are supernumerary dispensable parts of the karyotype which appear in some individuals of some populations in some species. Using advanced sequencing technology, we in silico characterized the high-copy DNA composition of Plantago lagopus with and without B chromosomes. The nuclear genome (2.46 pg/2C) was found to be relatively rich in repetitive sequences, with highly and moderately repeated elements making up 68% of the genome. Besides a centromere-specific marker, we identified a B-specific satellite and a repeat enriched in polymorphic A chromosome segments. The B-specific tandem repeat PLsatB originated from sequence amplification including 5S rDNA fragments.

Tissue section lifting for electron microscopy

1978 ◽  
Vol 36 (2) ◽  
pp. 86-87
Author(s):  
Adrian F. van Dellen
Keyword(s):  
Infectious Disease ◽  
Electron Microscopy ◽  
Tissue Culture ◽  
Organ System ◽  
Surrounding Tissue ◽  
Paraffin Sections ◽  
Surface Areas ◽  
Specific Determination ◽  
High Degree ◽  
Accuracy And Repeatability

The morphologic pathologist may require information on the ultrastructure of a non-specific lesion seen under the light microscope before he can make a specific determination. Such lesions, when caused by infectious disease agents, may be sparsely distributed in any organ system. Tissue culture systems, too, may only have widely dispersed foci suitable for ultrastructural study. In these situations, when only a few, small foci in large tissue areas are useful for electron microscopy, it is advantageous to employ a methodology which rapidly selects a single tissue focus that is expected to yield beneficial ultrastructural data from amongst the surrounding tissue. This is in essence what "LIFTING" accomplishes. We have developed LIFTING to a high degree of accuracy and repeatability utilizing the Microlift (Fig 1), and have successfully applied it to tissue culture monolayers, histologic paraffin sections, and tissue blocks with large surface areas that had been initially fixed for either light or electron microscopy.

Recent Studies on a Murine Leukemia Virus Grown in Tissue Culture

1967 ◽  
Vol 25 ◽  
pp. 106-107
Author(s):  
L. Z. de Tkaczevski ◽  
E. de Harven ◽  
C. Friend
Keyword(s):  
Tissue Culture ◽  
Solid Tumors ◽  
Murine Leukemia Virus ◽  
Leukemia Virus ◽  
Supernatant Fluid ◽  
Virus Particles ◽  
Friend Leukemia ◽  
Type C ◽  
Leukemia Viruses ◽  
Murine Leukemia

Despite extensive studies, the correlation between the morphology and pathogenicity of murine leukemia viruses (MLV) has not yet been clarified. The virus particles found in the plasma of leukemic mice belong to 2 distinct groups, 1 or 2% of them being enveloped A particles and the vast majority being of type C. It is generally believed that these 2 types of particles represent different phases in the development of the same virus. Particles of type A have been thought to be an earlier form of type C particles. One of the tissue culture lines established from Friend leukemia solid tumors has provided the material for the present study. The supernatant fluid of the line designated C-1A contains an almost pure population of A particles as illustrated in Figure 1. The ratio is, therefore, the reverse of what is unvariably observed in the plasma of leukemic mice where C particles predominate.

Cytoplasmic Tubules in Cells Infected with Laryngotracheitis Virus

1969 ◽  
Vol 27 ◽  
pp. 376-377
Author(s):  
A. M. Watrach
Keyword(s):  
Tissue Culture ◽  
Small Proportion ◽  
Chicken Embryo ◽  
Culture Cells ◽  
Tissue Culture Cells ◽  
Morphologic Characteristics ◽  
Infectious Laryngotracheitis ◽  
Laryngotracheitis Virus ◽  
In Cells

During a study of the development of infectious laryngotracheitis (LT) virus in tissue culture cells, unusual tubular formations were found in the cytoplasm of a small proportion of the affected cells. It is the purpose of this report to describe the morphologic characteristics of the tubules and to discuss their possible association with the development of virus.The source and maintenance of the strain of LT virus have been described. Prior to this study, the virus was passed several times in chicken embryo kidney (CEK) tissue culture cells.

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