scholarly journals THE DESOXYRIBONUCLEIC ACID CONTENT OF ANIMAL CELLS AND ITS EVOLUTIONARY SIGNIFICANCE

1951 ◽  
Vol 34 (4) ◽  
pp. 451-462 ◽  
Author(s):  
A. E. Mirsky ◽  
Hans Ris
Keyword(s):  
Dna Content ◽  
Acid Content ◽  
Evolutionary Significance ◽  
Desoxyribonucleic Acid ◽  
Animal Cells ◽  
Dna Contents ◽  
A Cell ◽  
Sperm Nuclei

1. Evidence is summarized for the constancy of DNA content for each set of chromosomes in the various cells of an organism. 2. The DNA contents of the egg and sperm nuclei are the same. 3. A brief survey is given of DNA contents per cell in invertebrates and vertebrates. (a) In invertebrates there is some slight evidence that when primitive and higher forms are compared the amount of DNA per cell is increased in the latter. (b) In fishes there is a tendency for the amount of DNA per cell to remain constant within the different species of a family. (c) The values of DNA per cell in lung fishes, amphibians, reptiles, and birds suggest that in the evolution of these vertebrates there has been a decline in DNA content per cell. 4. Concerning the significance of quantity of DNA per cell in vertebrates: (a) It appears not to be in proportion to the number of different genes in a cell. (b) It may be related to the number of strands in the chromosomes. (c) In homologous cells of different animals it is directly related to the mass of the cell.

Head Size and DNA Content in Bacteriophage T4

1972 ◽  
Vol 30 ◽  
pp. 200-201
Author(s):  
Fred Eiserling ◽  
A. H. Doermann ◽  
Linde Boehner
Keyword(s):  
Electron Microscopy ◽  
Dna Content ◽  
Bacteriophage T4 ◽  
Head Size ◽  
Virus Particles ◽  
Altered Protein ◽  
A Cell ◽  
Bacterial Viruses ◽  
A Site ◽  
Protein Shell

The control of form or shape inheritance can be approached by studying the morphogenesis of bacterial viruses. Shape variants of bacteriophage T4 with altered protein shell (capsid) size and nucleic acid (DNA) content have been found by electron microscopy, and a mutant (E920g in gene 66) controlling head size has been described. This mutant produces short-headed particles which contain 2/3 the normal DNA content and which are non-viable when only one particle infects a cell (Fig. 1).We report here the isolation of a new mutant (191c) which also appears to be in gene 66 but at a site distinct from E920g. The most striking phenotype of the mutant is the production of about 10% of the phage yield as “giant” virus particles, from 3 to 8 times longer than normal phage (Fig. 2).

Are phytoplankton population density maxima predictable through analysis of host and viral genomic DNA content?

2006 ◽  
Vol 86 (3) ◽  
pp. 491-498 ◽  
Author(s):  
Chris M. Brown ◽  
Janice E. Lawrence ◽  
Douglas A. Campbell
Keyword(s):  
Population Density ◽  
Dna Content ◽  
Viral Genome ◽  
Particle Assembly ◽  
Phytoplankton Population ◽  
Strong Linear Correlation ◽  
Viral Progeny ◽  
A Cell ◽  
Viral Proliferation ◽  
Viral Particle Assembly

Phytoplankton:virus interactions are important factors in aquatic nutrient cycling and community succession. The number of viral progeny resulting from an infection of a cell critically influences the propagation of infection and concomitantly the dynamics of phytoplankton populations. Host nucleotide content may be the resource limiting viral particle assembly. We present evidence for a strong linear correlation between measured viral burst sizes and viral burst sizes predicted from the host DNA content divided by the viral genome size, across a diversity of phytoplankton:viral pairs. An analysis of genome sizes therefore supports predictions of taxon-specific phytoplankton population density thresholds beyond which viral proliferation can trim populations or terminate phytoplankton blooms. We present corollaries showing that host:virus interactions may place evolutionary pressure towards genome reduction of both phytoplankton hosts and their viruses.

scholarly journals Genome Size Evaluations in Cockroaches: New Entries

2022 ◽  
Author(s):  
Manuela Monti ◽  
Carlo Alberto Redi ◽  
Ernesto Capanna
Keyword(s):  
Genome Size ◽  
Dna Content ◽  
Periplaneta Americana ◽  
Field Trapping ◽  
American Cockroach ◽  
Neural Cells ◽  
Blatta Orientalis ◽  
Leucophaea Maderae ◽  
Sperm Dna ◽  
Dna Contents

Abstract Background: Ten years ago the main Genome Size (GS) database contained records for 830 insects; although this number has now nearly doubled, 1645 (Gregory 2011 vs Gregory 2021 databases), the paucity of records highlights both the difficulty of animal field trapping and the time-consuming laboratory techniques to evaluate them. Thus, new entries are necessary to reach a satisfactory GS panorama for cockroaches. Results: We report GS values for nine cockroaches (order Blattodea, families Blattidae, Blaberidae and Ectobiidae, ex Blattelidae,), three of which are original additions to the ten already present in the GS database: the death’s head roach (Blaberus craniifer), the Surinam cockroach (Pycnoscelus surinamensis) and the Madeira cockroach (Leucophaea maderae). Three of our values confirm the existing data for the German (Blattella germanica), the oriental (Blatta orientalis) and the giant Mexican (Blabera fusca) cockroaches. Regarding the GS of the American cockroach (Periplaneta americana) the GS database contains two contrasting values (2.72 vs 3.41 pg). We suggest that the 2.72 pg value is likely to be the correct GS as it strikingly similar to our sperm DNA content evaluation (2.80 ± 0.11 pg). Finally, we suggest halving the published GS of the Argentine cockroach Blaptica dubia and the spotted cockroach (the gray cockroach) Nauphoeta cinerea as our estimates come from the evaluation of the sperm DNA content. The data already reported in the literature are based on DNA contents of neural cells (likely polyploid) obtained by grinding entire heads of animals.Conclusions: Although the paucity of the GS data does not allow firm considerations on the possible evolutionary role played by the GS in diversifying cockroach species, we offer two speculative hypotheses that need to be validated by increasing the available GS records: (i) the occurrence of a correlation between increasing 2N chromosome number and GS within the order Blattodea; and (ii) the possible occurrence of a polyploidization phenomenon doubling a basic GS of 0.58 pg of some termite families (superfamily Blattoidea, epifamily Termitoidae) up to the maximum GS value of 3.24 for the Blaberidae family within the order Blattodea (super-order Dictyoptera).

NUTRITION OF ANIMAL CELLS IN TISSUE CULTURE: VIII. DESOXYRIBONUCLEIC ACID PHOSPHORUS AS A MEASURE OF CELL MULTIPLICATION IN REPLICATE CULTURES

1954 ◽  
Vol 32 (1) ◽  
pp. 319-326
Author(s):  
George M. Healy ◽  
Dorothy C. Fisher ◽  
Raymond C. Parker
Keyword(s):  
Horse Serum ◽  
Cell Multiplication ◽  
Desoxyribonucleic Acid ◽  
Present Communication ◽  
Animal Cells ◽  
Defined Media ◽  
Chick Embryo Extract ◽  
Material Good ◽  
Cell Strains

A chemical method of estimating the size of cell populations in replicate cultures has been devised for use with certain cell strains from the mouse and rat. The method is based upon the determination of desoxyribonucleic acid phosphorus (DNAP). Although the method may be used as an alternative to the procedure of counting isolated, stained nuclei in a hemocytometer, it actually supplements such measurements and provides useful information on the DNA-content per cell. The method consists of a modified Schmidt and Thannhauser separation of ribonucleic acid (RNA) and desoxyribonucleic acid (DNA) followed by the spectrophotometric estimation of the orthophosphate. The present communication describes the procedures in detail and reports recoveries of RNAP and DNAP from mixtures of highly polymerized nucleic acids and various types of biological material. Good correlation was found between nuclear counts and DNAP values in natural media (containing horse serum and chick embryo extract) and in synthetic (chemically-defined) media. Finally, the efficiency of the dispensing apparatus most frequently employed in preparing replicate cultures from continuously stirred, washed cell suspensions has been determined by measuring the DNAP content of serially dispensed samples.

Plasmodium berghei-infected red cells sorted according to DNA content

Parasitology ◽  
1979 ◽  
Vol 78 (3) ◽  
pp. 263-270 ◽  
Author(s):  
R. J. Howard ◽  
F. L. Battye
Keyword(s):  
Red Blood Cells ◽  
Dna Content ◽  
Cell Sorting ◽  
Plasmodium Berghei ◽  
Blood Cells ◽  
Dye Uptake ◽  
Direct Proportion ◽  
Mouse Blood ◽  
Infected Blood ◽  
A Cell

SUMMARYA cell-sorting method is described for the analysis and separation of red blood cells in Plasmodium berghei-infected mouse blood based on their DNA content. This method involves a selective uptake of the bis-benzimidazole dye 33258 Hoechst, a DNA-binding dye, by red blood cells containing parasites. Infected blood is incubated at 37 °C with the dye then washed at 4 °C to remove unbound dye. Uninfected cells are then non-fluorescent at the characteristic wavelengths for 33258 Hoechst excitation and emission, whereas parasitized cells display fluorescence intensities in approximately direct proportion to the number of parasite nuclei (i.e. amount of parasite DNA) within the cell and can be sorted accordingly. Providing cells were incubated in a complex nutrient medium during dye uptake at 37°C, the sorted parasite cells produced lethal P. berghei infections when injected into BALB/c mice. The dyelabelling technique is simple and sufficient red blood cells at various stages of infection can be collected for biochemical or immunochemical studies by cell sorting.

The Cell's Biological Rods and Ropes

MRS Bulletin ◽  
1999 ◽  
Vol 24 (10) ◽  
pp. 27-31 ◽  
Author(s):  
David Boal
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Chemical Composition ◽  
Intermediate Filaments ◽  
Plant Cells ◽  
Cell Type ◽  
Animal Cells ◽  
Limited Variation ◽  
A Cell ◽  
Mechanical Elements

Despite a variety of shapes and sizes, the generic mechanical structure of cells is remarkably similar from one cell type to the next. All cells are bounded by a plasma membrane, a fluid sheet that controls the passage of materials into and out of the cell. Plant cells and bacteria reinforce this membrane with a cell wall, permitting the cell to operate at an elevated osmotic pressure. Simple cells, such as the bacterium shown in Figure 1a, possess a fairly homogeneous interior containing the cell's genetic blueprint and protein workhorses, but no mechanical elements. In contrast, as can be seen in Figure 1b, plant and animal cells contain internal compartments and a filamentous cytoskeleton—a network of biological ropes, cables, and poles that helps maintain the cell's shape and organize its contents.Four principal types of filaments are found in the cytoskeleton: spectrin, actin, microtubules, and a family of intermediate filaments. Not all filaments are present in all cells. The chemical composition of the filaments shows only limited variation from one cell to another, even in organisms as diverse as humans and yeasts. Membranes have a more variable composition, consisting of a bi-layer of dual-chain lipid molecules in which are embedded various proteins and frequently a moderate concentration of cholesterol. The similarity of the cell's mechanical elements in chemical composition and physical characteristics encourages us to search for universal strategies that have developed in nature for the engineering specifications of the cell. In this article, we concentrate on the cytoskeleton and its filaments.

Nuclear DNA content of three Eucalyptus species estimated by flow and image cytometry

2009 ◽  
Vol 57 (6) ◽  
pp. 524 ◽  
Author(s):  
Milene Miranda Praça ◽  
Carlos Roberto Carvalho ◽  
Carolina Ribeiro Diniz Boaventura Novaes
Keyword(s):  
Dna Content ◽  
Nuclear Dna ◽  
Methodological Approach ◽  
Nuclear Dna Content ◽  
Image Cytometry ◽  
Eucalyptus Species ◽  
International Consensus ◽  
Mean Values ◽  
Dna Contents ◽  
Nuclear Dna Contents

Previous flow cytometry (FCM) analyses delivered nearly equal mean values of nuclear 2C DNA content for Eucalyptus grandis Hill ex Maiden and E. urophylla S. T. Blake (1.33 pg and 1.34 pg, respectively), whereas E. globulus Labill. presented distinct mean values (1.09, 1.13 and 1.40). These differences have been attributed to the different methodological approach, utilised plant cultivar and presence of intrinsic metabolic compounds that affect fluorochrome fluorescence. In the present study, a FCM and image cytometry (ICM) design, following international consensus criteria, were adopted to reassess the nuclear DNA contents of the above-mentioned Eucalyptus species. Statistical analyses revealed either similar or discrepant nuclear DNA contents, depending on the standard species used and whether FCM or ICM was employed. Our results demonstrated that 2C DNA values obtained by FCM and ICM were most uniform when Solanum lycopersicum was used as a standard. Moreover, the values obtained for E. grandis and E. urophylla were close, but differed as much as 24.63% in relation to previous data, and E. globulus proportionally varied up to 25%. New DNA content values are suggested for these eucalypt species.

scholarly journals CHANGING NUCLEAR HISTONE PATTERNS DURING DEVELOPMENT III. THE DEOXYRIBONUCLEIC ACID CONTENT OF SPERMATOGENIC CELLS IN THE CRAB EMERITA ANALOGA

1969 ◽  
Vol 17 (9) ◽  
pp. 591-600 ◽  
Author(s):  
J. C. VAUGHN ◽  
R. D. LOCY
Keyword(s):  
Deoxyribonucleic Acid ◽  
Rat Tissues ◽  
Spermatogenic Cells ◽  
Spectral Absorption ◽  
Naturally Occurring ◽  
Emerita Analoga ◽  
Dna Contents ◽  
Nuclear Histone ◽  
Sperm Nuclei ◽  
Sperm Maturity

The deoxyribonucleic acid (DNA) content of spermatogenic cells of the decapod crab, Emerita analoga, has been cytophotometrically determined at various stages of development, using Feulgen-stained nuclei. The haploid DNA value is found to be 2.9 x 10–12 g, regardless of the nuclear histone content, which drops to cytochemically indetectable levels by sperm maturity. In determining this value, a precise extinction coefficient for Feulgen-stained nuclei was first determined using chicken, frog and toad erythrocyte nuclei and also nuclei from various rat tissues. The effect of naturally occurring nuclear histone depletion on the quantitative Feulgen reaction has also been examined. Identical hydrolysis curves and Feulgen spectral absorption curves are found for somatic nuclei, which contain a full histone complement, and for mature sperm nuclei, which do not contain histones. Loss of nuclear histone does not lead to a change in total Feulgen dye bound per nucleus, as early, middle and late spermatids have equal DNA contents as reflected by Feulgen binding, and primary spermatocytes contain 4 times this value, as expected from the DNA constancy law. The effect of histones (and other proteins) on quantitative Feulgen microspectrophotometry is discussed.

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