The nuclear content of desoxyribonucleic acid and some problems of Mammalian phylogenesis

Romanini, M. G. Manfredi

doi:10.1515/mamm.1985.49.3.369

Cited by 20 publications

(11 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The observed values (ng/μl DNA) were multiplied by the entire sample volume and divided by the sample weight. Using this approach, the number of nuclei per mg tissue was determined by applying known pg DNA per nucleus of the relevant species: The result was multiplied by the reference value of 7.3 pg DNA content per human nucleus (Manfredi Romanini, 1985), 7.2 pg DNA content per macaque nucleus (Manfredi Romanini, 1985) and 2.5 pg DNA content per chicken nucleus (Jacobson, 1991). Using this approach, the number of nuclei per mg tissue was determined by applying known pg DNA per nucleus of the relevant species.…”

Section: Methodsmentioning

confidence: 99%

Validation of the isotropic fractionator: Comparison with unbiased stereology and DNA extraction for quantification of glial cells

Bahney

Bartheld

2014

Journal of Neuroscience Methods

View full text Add to dashboard Cite

Background The “isotropic fractionator” (IF) is a novel cell counting technique that homogenizes fixed tissue, recovers cell nuclei in solution, and samples and quantifies nuclei by extrapolation. Studies using this technique indicate that the ratio of glia to neurons in the human brain is approximately 1:1 rather than the 10:1 or 50:1 ratio previously assumed. Although some results obtained with the IF have been similar to those obtained by stereology, the IF has never been calibrated or validated. It is conceivable that only a fraction of glial cell nuclei are recovered intact or recognized after the homogenization step. New Method To rule out this simple explanation for the claim of a 1:1 glia-neuron ratio, we compared cell numbers obtained from adjacent, weight-normalized samples of human and macaque monkey white matter using three techniques: the IF, unbiased stereology of histological sections in exhaustively sectioned samples, and cell numbers calculated from DNA extraction. Results and comparison of methods In primate forebrains, the IF yielded 73,000–90,000 nuclei/mg white matter, unbiased stereology yielded 75,000–92,000 nuclei/mg, with coefficients of error ranging from 0.013–0.063, while DNA extraction yielded only 4,000–23,000 nuclei/mg in fixed white matter tissues. Conclusions Since the IF revealed about 100% of the numbers produced by unbiased stereology, there is no significant underestimate of glial cells. This confirms the notion that the human brain overall contains glial cells and neurons with a ratio of about 1:1 far from the originally assumed ratio of 10:1 in favor of glial cells.

show abstract

Section: Methodsmentioning

confidence: 99%

Validation of the isotropic fractionator: Comparison with unbiased stereology and DNA extraction for quantification of glial cells

Bahney

Bartheld

2014

Journal of Neuroscience Methods

View full text Add to dashboard Cite

show abstract

“…Genome mass was picograms of DNA per diploid nucleus and collated without priority by Olmo (1983) and Manfredi Romanini (1985). Chromosome numbers were derived from Altmann & Dittmer (1972) and Hsu & Benirschke (1967^1976).…”

Section: Methodsmentioning

confidence: 99%

Mammalian sperm morphometry

Gage

1998

Proc. R. Soc. Lond. B

165

152

View full text Add to dashboard Cite

Understanding the adaptive signi¢cance of sperm form and function has been a challenge to biologists because sperm are highly specialized cells operating at a microscopic level in a complex environment. A fruitful course of investigation has been to use the comparative approach. This comparative study attempts to address some fundamental questions of the evolution of mammalian sperm morphometry. Data on sperm morphometry for 445 mammalian species were collated from published sources. I use contemporary phylogenetic analysis to control for the inherent non-independence of species and explore relationships between the morphometric dimensions of the three essential spermatozoal components: head, mid-piece and £agellum. Energy for £agellar action is metabolized by the mitochondrial-dense mid-piece and these combine to propel the sperm head, carrying the male haplotype, to the ovum. I therefore search for evolutionary associations between sperm morphometry and body mass, karyotype and the duration of oestrus. In contrast to previous ¢ndings, there is no inverse correlation between body weight and sperm length. Sperm mid-piece and £agellum lengths are positively associated with both head length and area, and the slopes of these relationships are discussed. Flagellum length is positively associated with mid-piece length but, in contrast to previous research and after phylogenetic control, I ¢nd no relationship between £agellum length and the volume of the mitochondrial sheath. Sperm head dimensions are not related to either genome mass or chromosome number, and there are no relationships between sperm morphometry and the duration of oestrus.

show abstract

“…For absolute DNA measures, we assumed the 2C thymocyte mouse content to be 6.80 pg (Manfredi Romanini 1985).…”

Section: Experimental Designmentioning

confidence: 99%

Genome size in parental and hybrid species of Bacillus (Insecta, Phasmatodea) from southeastern Sicily: a flow cytometric analysis

Marescalchi¹,

Scali²,

Zuccotti³

1990

Genome

View full text Add to dashboard Cite

MARESCALCHI, O., SCALI, V., and ZUCCOTTI, M. 1990. Genome size in parental and hybrid species of Bacillus (Insecta, Phasmatodea) from southeastern Sicily: a flow cytometric analysis. Genome, 33: 789-793. In Sicily five Bacillus taxa are found: two bisexuals, B. grandii (2n = 34, female; 2n = 33, male) and B. rossius (2n = 36, female; 2n = 35, male), and three thelytokous, B. atticus (2n = 34), B. whitei (2n = 35), and B. lynceorurn (3n = 52). Their cytofluorometric 2C DNA values, in picograms, in order are 5.22 ( Q ) -4.31 ( 0 ) ; 4.33 ( Q ) -3.89 ( 0 ) ; 4.40; 4.53; and 6.80. These values represent the first flow cytofluorometric data on phasmatodean genome size. The highest value of B. grandii and the lowest one of B. rossius appear to be related to abundance and scarcity of C-heterochromatin, respectively, which is also rather low in B. atticus. The genome size of B. whitei agrees perfectly with its shown hybrid derivation from B. grandii and B. rossius. On the other hand the value of B. lynceorurn is significantly lower than the one expected (7.38 pg) on the basis of its formerly suggested hybrid origin from the backcross B. whitei x B. grandii, but it appears much closer to, and not significantly different from, the value of 6.97 pg expected according to the newly suggested double allotriploid origin, mainly based on electrophoretic evidence, from B. atticus, B. rossius, and B. grandii. Finally, as far as Bacillus taxa are concerned, average stick-insect genome size appears to be just lower than that of other orthopteroid insects, and much lower (10 times) than that of the leaf insect Extatosorna tiaraturn, obtained through static cytometry on Feulgen-stained DNA squashes. MARESCALCHI, O., SCALI, V., et ZUCCOTTI, M. 1990. Genome size in parental and hybrid species of Bacillus (Insecta, Phasmatodea) from southeastern Sicily: a flow cytometric analysis. Genome, 33 : 789-793. Cinq taxons Bacillus existent en Sicile : deux sont bisexuels, le B. grandii (2n = 34, femelle; 2n = 33, m5le) et le B. rossius (2n = 36, femelle; 2n = 35, m8le) et trois sont des gynoparthenogeniques (thelyotokistes) : B. atticus (2n = 34), B. whitei (2n = 35) et B. lynceorurn (3n = 52). Les valeurs des ADN 2C, en picogrammes, determinees par cytofluorometrie, sont dans l'ordre : 5,22 ( Q ) -4,31 ( 0 ) ; 4,33 ( Q ) -3,89 ( 0 ) ; 4,40; 433; et 6,80. Ces valeurs representent la premikre donnee de flux cytofluoromCtrique sur la dimension genomique des Phasmatodeens. La valeur la plus elevee de B. grandii et la plus faible de B. rossius semblent etre respectivement relikes a I'abondance et a la rarete de l'heterochromatine C, laquelle est kgalement plut8t faible chez le B. atticus. La dimension du genome de B. whitei correspond parfaitement a celle de sa derivation hybride demontree de B. grandii et B. rossius. D'autre part, la valeur de B. lynceorurn est significativement inferieure a celle qui etait attendue (7,38 pg) d'aprks son origine hybride anterieurement suggeree a partir d'un retrocroisement B. whitei x B. grandii; toutefois, cette v...

show abstract

The nuclear content of desoxyribonucleic acid and some problems of Mammalian phylogenesis

Cited by 20 publications

References 27 publications

Validation of the isotropic fractionator: Comparison with unbiased stereology and DNA extraction for quantification of glial cells

Validation of the isotropic fractionator: Comparison with unbiased stereology and DNA extraction for quantification of glial cells

Mammalian sperm morphometry

Genome size in parental and hybrid species of Bacillus (Insecta, Phasmatodea) from southeastern Sicily: a flow cytometric analysis

Contact Info

Product

Resources

About