Genetic instability of multiple buds of Pinuscoulteri regenerated from tissue culture

1982 ◽  
Vol 12 (1) ◽  
pp. 93-101 ◽  
Author(s):  
Kamlesh R. Patel ◽  
Graeme P. Berlyn
Keyword(s):  
Nuclear Dna ◽  
Internal Standard ◽  
Progressive Increase ◽  
Culture Conditions ◽  
Dna Contents ◽  
Large Populations ◽  
Multiple Buds ◽  
Chicken Erythrocytes ◽  
Cellular Dna ◽  
Over Time

Embryo expiants ofPinuscoulteri D. Don. were cultured on agar media (modified from Campbell and Durzan 1975) only supplemented with 2.25 mg•L−1 of benzyl amino purine (BAP). Nuclear DNA contents were measured in cells of the embryo explants, callus, and buds regenerated from these explants, and sand-germinated seedlings. Measurements were made at weekly intervals during 6 weeks of culture. Absolute amounts of cellular DNA were determined with a microspectrophotometer using chicken erythrocytes as an internal standard. Initially, the nuclei had a DNA level between 2C and 4C with a mean of 3C. The sand-grown seedlings remained within this range, with an increased frequency of 4C nuclei in the 6-week seedlings. However, cells from callus and regenerated buds showed a progressive increase in DNA level over time. After 42 days in culture, the buds contained large populations of cells at the 8C level and a considerable number of cells with DNA levels above 8C. In addition, the nuclei showed a considerable increase in chromosomal aberrations including bridges, micronuclei, lagging chromosomes, and fragmentation. Nuclear volume also increased over time in the regenerated buds. It is therefore concluded that culture conditions, perhaps cytokinin content, increased the levels of nuclear DNA. These increased levels could be the result of polyploidy, polyteny, hyperaneuploidy, or a combination of these types of nuclear organization.

scholarly journals Measurement of cellular DNA mass by flow microfluorometry with use of a biological internal standard.

1978 ◽  
Vol 26 (2) ◽  
pp. 145-148 ◽  
Author(s):  
E Tannenbaum ◽  
M Cassidy ◽  
O Alabaster ◽  
C Herman
Keyword(s):  
Dna Content ◽  
Internal Standard ◽  
Cell Populations ◽  
Experimental Cell ◽  
Flow Microfluorometry ◽  
Chicken Erythrocytes ◽  
Cellular Dna ◽  
Biological Standard

Use of a biological standard (chicken erythrocytes) mixed with experimental cell populations allows control of all variables in flow microfluorometric determination of DNA content. These variables include both staining and instrument procedures. In addition, the use of a biological standard allows determination of cellular DNA mass in unperturbed cell populations. DNA mass measured by FMF technique correlates closely with values reported in the literature that used biochemical techniques.

scholarly journals Nuclear DNA Content and Ploidy Levels in the Genus Ipomoea

1994 ◽  
Vol 119 (1) ◽  
pp. 110-115 ◽  
Author(s):  
Peggy Ozias-Akins ◽  
Robert L. Jarret
Keyword(s):  
Flow Cytometry ◽  
Dna Content ◽  
Large Scale ◽  
Nuclear Dna ◽  
Internal Standard ◽  
Nuclear Dna Content ◽  
Ploidy Levels ◽  
Genetic Structure Of Populations ◽  
Chicken Erythrocytes ◽  
Nuclei Ploidy Level

The nuclear DNA content of 53 accessions from 24 Ipomoea (Convolvulaceae) species, including four sweetpotato cultivars, was determined by flow cytometry of DAPI-stained nuclei. Ploidy level and DNA content were significantly correlated within the genus, but more highly so within species that contained multiple cytotypes. DNA content of cultivated Z. batatas (L.) Lam. (4.8 to 5.3 pg/2C nucleus) and feral tetraploid I. batatas (3.0 to 3.5 pg/2C nucleus) was estimated from the known DNA content of chicken erythrocytes (2.33 pg), which were used as an internal standard. Tetraploid forms of Z. cordato-triloba Dennstedt also were identified. Ploidy analysis using flow cytometry is rapid and suitable for large-scale experiments such as studying the genetic structure of populations of Z. batatas and related species. Chemical name used: 4′,6-diamidino-2-phenylindole (DAPI).

scholarly journals Nonspecific light loss and intrinsic DNA variation problems associated with feulgen DNA cytophotometry.

1979 ◽  
Vol 27 (10) ◽  
pp. 1377-1379 ◽  
Author(s):  
J P Miksche ◽  
S S Dhillon ◽  
G P Berlyn ◽  
K J Landauer
Keyword(s):  
Nuclear Dna ◽  
Internal Standard ◽  
Root Tip ◽  
Scanning Method ◽  
Dna Variation ◽  
Wavelength Scanning ◽  
Light Loss ◽  
Chicken Erythrocytes ◽  
Dna Measurements

Nonspecific light loss by the cell-wall-plus-cytoplasm (CWC) can cause a 50% increase in Feulgen absorption units in peanut root-tip nuclei as determined by scanning at 450 nm, whereas this phenomenon is not evident with chicken erythrocytes. A two wavelength scanning method of subtracting nonspecific 450 nm absorption from 550 nm Feulgen absorption values eliminated the nonspecific light loss in CWC, However, the two wavelength scanning method is time consuming and somewhat impractical with a regular scanning microdensitometer such as Vickers M85. Elimination of the problem of nonspecific light loss is suggested by careful determination of background setting with the spot position close to the nucleus in CWC. The accuracy of the CWC background setting method was further tested by comparison with subtraction method. The use of plant nucleis as an internal standard in plant DNA measurements was also evaluated. Significant variation among the replicate slides due to the variation in pine nuclear DNA amounts was observed and plant nuclei generally are not reliable internal standards. Mature chicken erythrocytes are recommended as an internal standard because the cell type and metabolic state is known.

scholarly journals Nuclear DNA contents, rDNAs, and karyotype evolution in subgenus Vicia: III. The heterogeneous section Hypechusa

PROTOPLASMA ◽  
2006 ◽  
Vol 228 (4) ◽  
pp. 167-177 ◽  
Author(s):  
P. Caputo ◽  
M. Frediani ◽  
G. Venora ◽  
C. Ravalli ◽  
M. Ambrosio ◽  
...  
Keyword(s):  
Nuclear Dna ◽  
Karyotype Evolution ◽  
Dna Contents ◽  
Nuclear Dna Contents

scholarly journals Unexpected heterozygosity in an island mouflon population founded by a single pair of individuals

2006 ◽  
Vol 274 (1609) ◽  
pp. 527-533 ◽  
Author(s):  
Renaud Kaeuffer ◽  
David W Coltman ◽  
Jean-Louis Chapuis ◽  
Dominique Pontier ◽  
Denis Réale
Keyword(s):  
Genetic Diversity ◽  
Wild Population ◽  
Ovis Aries ◽  
Stochastic Simulations ◽  
Single Pair ◽  
Small Populations ◽  
Short Period ◽  
Large Populations ◽  
History Of ◽  
Over Time

In population and conservation genetics, there is an overwhelming body of evidence that genetic diversity is lost over time in small populations. This idea has been supported by comparative studies showing that small populations have lower diversity than large populations. However, longitudinal studies reporting a decline in genetic diversity throughout the whole history of a given wild population are much less common. Here, we analysed changes in heterozygosity over time in an insular mouflon ( Ovis aries ) population founded by two individuals in 1957 and located on one of the most isolated locations in the world: the Kerguelen Sub-Antarctic archipelago. Heterozygosity measured using 25 microsatellite markers has actually increased over 46 years since the introduction, and exceeds the range predicted by neutral genetic models and stochastic simulations. Given the complete isolation of the population and the short period of time since the introduction, changes in genetic variation cannot be attributed to mutation or migration. Several lines of evidence suggest that the increase in heterozygosity with time may be attributable to selection. This study shows the importance of longitudinal genetic surveys for understanding the mechanisms that regulate genetic diversity in wild populations.

Poliomyelitis

2020 ◽  
pp. 151-186
Author(s):  
Michael B. A. Oldstone
Keyword(s):  
Nineteenth Century ◽  
Seventeenth Century ◽  
Paralytic Poliomyelitis ◽  
Disease Entity ◽  
Poliomyelitis Virus ◽  
Specific Disease ◽  
Large Populations ◽  
Attenuated Viruses ◽  
Over Time

This chapter addresses how polio was first discovered and then controlled, the problems with its elimination, and the argument for continued vaccination to ensure control. Polio was not defined as a specific disease entity until the late seventeenth century. Meanwhile, paralytic poliomyelitis epidemics first became known in the nineteenth century. Whether or not sporadic outbreaks of paralytic poliomyelitis occurred earlier is less certain and a matter of disagreement. The chapter then looks at the three main personalities who were fundamental in developing the vaccine for poliomyelitis: Jonas Salk, Albert Sabin, and Hilary Koprowski. Jonas Salk and his colleagues chemically inactivated the poliomyelitis virus with formaldehyde and provided a vaccine that produced immunity and dramatically lowered the incidence of poliomyelitis. However, this immunity waned over time. Additionally, administration by needle made vaccinations of large populations difficult. For these and other reasons, Koprowski, Sabin, and others independently worked on the development of a vaccine with live attenuated viruses. Without such combined efforts, the vaccine would never have materialized.

scholarly journals Multi-year particle fluxes in Kongsfjorden, Svalbard

2018 ◽  
Vol 15 (17) ◽  
pp. 5343-5363 ◽  
Author(s):  
Alessandra D'Angelo ◽  
Federico Giglio ◽  
Stefano Miserocchi ◽  
Anna Sanchez-Vidal ◽  
Stefano Aliani ◽  
...  
Keyword(s):  
Time Series ◽  
Sea Ice ◽  
Ocean Circulation ◽  
Progressive Increase ◽  
Physical Parameters ◽  
Air Temperatures ◽  
Inorganic Matter ◽  
Particle Fluxes ◽  
Particulate Fluxes ◽  
Over Time

Abstract. High-latitude regions are warming faster than other areas due to reduction of snow cover and sea ice loss and changes in atmospheric and ocean circulation. The combination of these processes, collectively known as polar amplification, provides an extraordinary opportunity to document the ongoing thermal destabilisation of the terrestrial cryosphere and the release of land-derived material into the aquatic environment. This study presents a 6-year time series (2010–2016) of physical parameters and particle fluxes collected by an oceanographic mooring in Kongsfjorden (Spitsbergen, Svalbard). In recent decades, Kongsfjorden has been experiencing rapid loss of sea ice coverage and retreat of local glaciers as a result of the progressive increase in ocean and air temperatures. The overarching goal of this study was to continuously monitor the inner fjord particle sinking and to understand to what extent the temporal evolution of particulate fluxes was linked to the progressive changes in both Atlantic and freshwater input. Our data show high peaks of settling particles during warm seasons, in terms of both organic and inorganic matter. The different sources of suspended particles were described as a mixing of glacier carbonate, glacier siliciclastic and autochthonous marine input. The glacier releasing sediments into the fjord was the predominant source, while the sediment input by rivers was reduced at the mooring site. Our time series showed that the seasonal sunlight exerted first-order control on the particulate fluxes in the inner fjord. The marine fraction peaked when the solar radiation was at a maximum in May–June while the land-derived fluxes exhibited a 1–2-month lag consistent with the maximum air temperature and glacier melting. The inter-annual time-weighted total mass fluxes varied by 2 orders of magnitude over time, with relatively higher values in 2011, 2013, and 2015. Our results suggest that the land-derived input will remarkably increase over time in a warming scenario. Further studies are therefore needed to understand the future response of the Kongsfjorden ecosystem alterations with respect to the enhanced release of glacier-derived material.

scholarly journals An Automated Perifusion System for Modifying Cell Culture Conditions over Time

2016 ◽  
Vol 18 (1) ◽  
Author(s):  
Nicholas B. Whitticar ◽  
Elisha W. Strahler ◽  
Parthiban Rajan ◽  
Savas Kaya ◽  
Craig S. Nunemaker
Keyword(s):  
Cell Culture ◽  
Culture Conditions ◽  
Cell Culture Conditions ◽  
Perifusion System ◽  
Over Time
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