Use of flow cytometry to screen for the effects of environmental mutagens: baseline DNA values in cottonmouth snakes.
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Animals↗
Biomedical subjects
T R Tiersch
Publications and source records attributed to T R Tiersch.
Rapid identification of sex in birds by flow cytometry.
A rapid method to identify sex in birds is described. The method requires microliter volumes of blood, and, under appropriate conditions, results can be available within an hour of sample collection. Samples can be stored at 4 degrees C or -20 degrees C without sacrificing the ability to discriminate sex differences in DNA content. The assay will find utility in laboratory, field, and applied studies, in other classes of vertebrates, and in studies on the dynamics of genome size within and among populations.
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Reference standards for flow cytometry and application in comparative studies of nuclear DNA content.
Nuclear DNA mass in cells from a reference species can be used to obtain high-resolution estimates of DNA mass from a target species. In our study of DNA mass in cells from 45 selected species, representing each of the major vertebrate classes, we have obtained values of from 1.5 to 110.0 pg of DNA. Because values in or near this range would be expected in the study of nuclear DNA mass in vertebrates and other organisms, the species in this report can provide a useful catalogue of references for comparative studies of DNA.
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Estimation of nuclear DNA content by flow cytometry in fishes of the genus Xiphophorus.
1. By use of flow cytometry we measured nuclear DNA content in cells from 16 stocks representing 9 species of the genus Xiphophorus. 2. Significant differences were detected between certain stocks and species with respect to DNA content. 3. Male-female differences were apparent in 5 of 7 stocks in which males and females were studied. 4. Estimation of nuclear DNA content is of potential significance in connection with the genetics of sex determination and the study of taxonomic relationships.
Animals↗
Apomorphine-induced vomiting in rainbow trout (Salmo gairdneri).
1. The LD50 for a 7-day period following intraperitoneal injection of apomorphine-HCl was calculated to be 158 mg/kg in rainbow trout. 2. Intraperitoneal injection of apomorphine at doses of 60 mg/kg or greater caused vomiting of plastic balls which had been placed in the stomachs of rainbow trout. 3. Apomorphine-induced effects included vomiting, vomiting behavior, toxicity, increased respiration, impaired motor control and equilibrium, and increased aggression. 4. The vomiting control mechanism of trout may be similar to that described in mammals.
Aggression↗
Improved attachment and spreading in primary cell cultures of the eastern oyster, Crassostrea virginica.
At present, establishment of a cell line from bivalve molluscs has been unsuccessful, and in vitro work is limited to primary cell cultures. We sought to improve attachment and spreading of cells of the eastern oyster, Crassostrea virginica, to aid primary cultures and to assist development of a bivalve cell line. Our objectives were to examine the effects of substrate on ventricle cell viability, attachment, and spreading by testing of collagen I, collagen IV, fibronectin, laminin, poly-D-lysine, and two types of uncoated tissue culture plates (Falcon and Corning). Experiments were conducted by incubating cells with the various substrates for 24 h and 5 d. An assay with a tetrazolium compound (MTS) was used to estimate cell numbers based on metabolic activity. Although differences in MTS assay values for substrate effect on cell viability were detected at 24 h and at 5 d (P > 0.0001), these were attributed to variations in metabolic activity due to different levels of attachment and spreading among treatments. Differences among treatments were detected in attachment and spreading at 24 h and 5 d (for all, P > 0.0001). At 24 h, poly-D-lysine induced the highest levels of attachment and spreading; no other factor performed better than the uncoated Falcon substrate, and collagen I performed most poorly. At 5 d, poly-D-lysine and the uncoated Corning substrate induced significantly higher levels of attachment and spreading than did the uncoated Falcons substrate, and collagen I performed most poorly. From these results, poly-D-lysine best promoted cell attachment and spreading. Fibronectin (at 24 h) and laminin (at 5 d) warrant further study. Along with improvements in medium composition, future work should involve screening of other attachment factors and combinations of factors, including those of bivalve origin.
Animals↗
On the evolution of genome size of birds.
We measured genome size (nuclear DNA content) by fluorescence flow cytometry in 55 species of birds representing 12 different orders. Similar studies were performed in approximately 100 species by laboratories using absorption cytophotometry of Feulgen-stained nuclei. Although there have been apparent discrepancies in the assigned values for the species used as a reference, the values obtained in the different laboratories are generally in agreement. When the data are standardized in relation to a diploid (2C) value of 2.5 picograms (pg) of DNA for the domestic chicken (Gallus gallus domesticus), the mean for DNA content in 135 species representing 17 orders is 2.82 +/- 0.33 (SD) pg with a range of 2.0-3.8 pg. Thus the genome size of birds is the most conservative of any vertebrate class and, all values considered, is smaller and more uniform in size than previous estimates would indicate. This could be explained by a previously unexplored hypothesis: that the genome of birds has evolved from a small ancestral genome that was reduced before emergence of the protoavian.
Animals↗