Brian McCaldin - Academia.edu (original) (raw)
Papers by Brian McCaldin
Biochemistry international, 1988
The effects of cell density and growth in 10% foetal bovine serum and 10% newborn calf serum on t... more The effects of cell density and growth in 10% foetal bovine serum and 10% newborn calf serum on the activity of the enzyme (Na+ + K+)-ATPase were studied in 3T3 and SV3T3 cells. The enzyme activity decreases in 3T3 cells grown in foetal bovine serum as the cells approach confluency while in those grown in newborn calf serum the enzyme activity increases. The (Na+ + K+)-ATPase activity does not change with increase in cell density in SV3T3 cells grown in foetal bovine serum while the enzyme activity in those grown in newborn calf serum increases with increase in cells density up to about 1.35 x 10(5) cells/sq. cm. and then decreases with further increase in cell number. At confluency it was found that the enzyme activity is higher in the SV3T3 as compared to the 3T3 cells when the cells were grown in 10% foetal bovine serum, whereas in those grown in 10% newborn calf serum the enzyme activity is higher in the 3T3 as compared to the SV3T3 cells.
Biochemistry international, 1989
The activities of membrane marker enzymes in normal (3T3) and simian virus transformed mouse cell... more The activities of membrane marker enzymes in normal (3T3) and simian virus transformed mouse cells (SV3T3) are affected not only by densities of cultures but also by the sera types used in the growth media. We have assayed the levels of 5'nucleotidase, monoamine oxidase and rotenone insensitive NADH ferricyanide reductase in these cells grown to sparse and confluent cultures in medium supplemented with 10% newborn calf serum (n.c.s.) or in medium supplemented with 10% foetal bovine serum (f.b.s.). It was found that in 3T3 cells grown in 10% f.b.s. the transition from sparse to confluent cultures was associated with a reduction in the activities of the marker enzymes while in those grown in 10% n.c.s., the activities of these enzymes increased. In the SV3T3 cells, the activities of all the enzymes except for monoamine oxidase decreased from sparse to confluent culture densities in cells grown in 10% n.c.s. whereas in those grown in 10% f.b.s. there were no significant change in t...
Biochemical Journal, 1979
The nucleoside triphosphate-stimulated efflux of RNA from isolated nuclei was studied under a ran... more The nucleoside triphosphate-stimulated efflux of RNA from isolated nuclei was studied under a range of conditions, and the effects of these conditions on the process were compared with the properties of the nucleoside triphosphatase located in the pore complex. A marked similarity between the rate of efflux and the rate of nucleoside triphosphate hydrolysis was apparent, in terms of substrate specificity, sensitivity to treatment with insolubilized trypsin, kinetics and the effects of increased ionic strength and of many inhibitors. These results are taken, in view of earlier evidence, to suggest that the activity of the nucleoside triphosphatase is a prerequisite for nucleo-cytoplasmic RNA transport in vivo. There are some indications that the nuclear-envelope lipid is also involved in regulating the efflux process.
Biochemical Journal, 1979
The nucleoside triphosphatase activities of the nuclear envelopes from rat liver, pig liver and s... more The nucleoside triphosphatase activities of the nuclear envelopes from rat liver, pig liver and simian-virus-40-transformed mouse-embryo 3T3 cells were shown to exhibit similar parperties. All three preparations hydrolyse ATP, 2′-dATP, 3′-dATP, GTP, CTP and UTP in the presence of Mg2+, Ca2+, Mn2+ and Co2+ with a pH optimum of 8.0, are sensitive to inhibition by mercurials, arsenicals, quercetin, proflavin and adenosine 5′-[γ-thio]triphosphate and are partially inactivated by exposure to high ionic strength. The kinetic behaviour is similar for all substrates irrespective of the source of material. The typical Eadie-Hofstee plot, which is concave upwards at pH 8.0 when the ionic strength is 20mM, becomes linear when the pH is increased to 8.5 or the ionic strength to 160mM. The overall evidence, particularly the labelling of only one polypeptide by [gamma-32P]ATP, suggests that under the conditions of preparation and assay used only one class of nucleoside triphosphatase active sites...
Biochemistry international, 1987
The effects of serum and cell density on the concentration of cyclic AMP, cyclic GMP in normal mo... more The effects of serum and cell density on the concentration of cyclic AMP, cyclic GMP in normal mouse fibroblasts cells (3T3 cells) and their Simian Virus 40 transformed derivative (SV3T3 cells) were studied. 3T3 cells grown in 10% foetal bovine serum exhibit density dependent inhibition of growth and associated with this in an increase in the concentration of cyclic AMP, a decrease in the concentration of cyclic GMP and an increase in the ratio (cyclic AMP/cyclic GMP) of the cyclic nucleotides. 3T3 cells grown in 10% newborn calf serum exhibit a higher saturation density and this is associated with a low concentration of cyclic AMP and a high concentration of cyclic GMP. SV3T3 cells grown in either 10% foetal bovine serum or 10% newborn calf serum show high saturation densities and this is associated with a low and decreasing concentration of cyclic AMP and a high concentration of cyclic GMP. When the level of the cyclic AMP in both cell lines was artificially raised by adding dibut...
Biochemical Medicine and Metabolic Biology, 1987
The 3T3 cells in culture exhibit density-dependent inhibition of growth (1) in opposition to the ... more The 3T3 cells in culture exhibit density-dependent inhibition of growth (1) in opposition to the simian virus-transformed 3T3 (SV3T3) cells which have the ability to grow to much higher densities (2). The density-dependent inhibition of growth is associated with decreases in the uptake of amino acid (3,4), phosphate (5-S), and glucose (9-12), while in the virus-transformed cells the uptake of these nutrients has been shown to be consistently high (3,5,13-l@. Since the transport of amino acid, glucose, and phosphate is a Na-dependent process (19-21), the maintenance of the sodium gradient across the cell membrane which is largely regulated by the Na-K pump is of importance in regulating cell growth. The activity of the Na-K pump in cultured cells has been shown by Aiton and Lamb (22) to be affected by serum concentration in the growth media. We have shown that sera types can also affect the activity of the Na-K pump in 3T3 cells (23) and also of several other membrane-bound enzymes (24). Since the 3T3 cells when first established were grown in medium supplemented with fetal bovine serum (l), while the SV3T3 cells were established in medium supplemented with newborn calf serum (2), we thought that the use of these two cell lines for comparing normal and malignant growth is only meaningful if the SV3T3 cells are grown in the same serum as that used in establishing the 3T3 cells. In this paper we report the effects of cell population density on the activity of Na-K pump and their roles in growth regulation in 3T3 and SV3T3 cells grown in medium supplemented with fetal bovine serum. Materials MATERIALS AND METHODS Swiss 3T3 and SV3T3 cells and materials needed for the growth of the cells which includes Dulbecco's modification of Eagle's minimal essential medium, fetal bovine serum, and trypsin were obtained from Flow Laboratories (Irvive,
Alimentary Pharmacology and Therapeutics, 1998
Biochemical Journal, 1979
The effect of 3′-deoxyadenosine (cordycepin) on mRNA efflux from isolated SV40-3T3 cell nuclei ha... more The effect of 3′-deoxyadenosine (cordycepin) on mRNA efflux from isolated SV40-3T3 cell nuclei has been studied and compared with its effect on the nucleoside triphosphatase activity in the isolated nuclear envelope. Inhibition of mRNA efflux occurs rapidly, but is dependent on the presence of ATP. Half-maximal inhibition occurs with 40 microM-cordycepin. The effect is not simulated by 2′-deoxyadenosine or by actinomycin D, and adenosine provides a substantial degree of protection against it. Cordycepin does not directly inhibit the nucleoside triphosphatase. The stimulation of this enzyme by poly(A) is not affected unless the poly(A) and cordycepin are incubated together with nuclear lysate in the presence of ATP; in this case the stimulation is significantly reduced. Possible interpretations of these results and their relevance for understanding the system in vivo for nucleo-cytoplasmic messenger transport are discussed.
Biochemical Society transactions, 1979
Journal of Cellular Physiology, 1985
Digestive and Liver Disease, 2005
Biochemical Society transactions, 1979
Biochemistry international, 1988
The effects of cell density and growth in 10% foetal bovine serum and 10% newborn calf serum on t... more The effects of cell density and growth in 10% foetal bovine serum and 10% newborn calf serum on the activity of the enzyme (Na+ + K+)-ATPase were studied in 3T3 and SV3T3 cells. The enzyme activity decreases in 3T3 cells grown in foetal bovine serum as the cells approach confluency while in those grown in newborn calf serum the enzyme activity increases. The (Na+ + K+)-ATPase activity does not change with increase in cell density in SV3T3 cells grown in foetal bovine serum while the enzyme activity in those grown in newborn calf serum increases with increase in cells density up to about 1.35 x 10(5) cells/sq. cm. and then decreases with further increase in cell number. At confluency it was found that the enzyme activity is higher in the SV3T3 as compared to the 3T3 cells when the cells were grown in 10% foetal bovine serum, whereas in those grown in 10% newborn calf serum the enzyme activity is higher in the 3T3 as compared to the SV3T3 cells.
Biochemistry international, 1989
The activities of membrane marker enzymes in normal (3T3) and simian virus transformed mouse cell... more The activities of membrane marker enzymes in normal (3T3) and simian virus transformed mouse cells (SV3T3) are affected not only by densities of cultures but also by the sera types used in the growth media. We have assayed the levels of 5'nucleotidase, monoamine oxidase and rotenone insensitive NADH ferricyanide reductase in these cells grown to sparse and confluent cultures in medium supplemented with 10% newborn calf serum (n.c.s.) or in medium supplemented with 10% foetal bovine serum (f.b.s.). It was found that in 3T3 cells grown in 10% f.b.s. the transition from sparse to confluent cultures was associated with a reduction in the activities of the marker enzymes while in those grown in 10% n.c.s., the activities of these enzymes increased. In the SV3T3 cells, the activities of all the enzymes except for monoamine oxidase decreased from sparse to confluent culture densities in cells grown in 10% n.c.s. whereas in those grown in 10% f.b.s. there were no significant change in t...
Biochemical Journal, 1979
The nucleoside triphosphate-stimulated efflux of RNA from isolated nuclei was studied under a ran... more The nucleoside triphosphate-stimulated efflux of RNA from isolated nuclei was studied under a range of conditions, and the effects of these conditions on the process were compared with the properties of the nucleoside triphosphatase located in the pore complex. A marked similarity between the rate of efflux and the rate of nucleoside triphosphate hydrolysis was apparent, in terms of substrate specificity, sensitivity to treatment with insolubilized trypsin, kinetics and the effects of increased ionic strength and of many inhibitors. These results are taken, in view of earlier evidence, to suggest that the activity of the nucleoside triphosphatase is a prerequisite for nucleo-cytoplasmic RNA transport in vivo. There are some indications that the nuclear-envelope lipid is also involved in regulating the efflux process.
Biochemical Journal, 1979
The nucleoside triphosphatase activities of the nuclear envelopes from rat liver, pig liver and s... more The nucleoside triphosphatase activities of the nuclear envelopes from rat liver, pig liver and simian-virus-40-transformed mouse-embryo 3T3 cells were shown to exhibit similar parperties. All three preparations hydrolyse ATP, 2′-dATP, 3′-dATP, GTP, CTP and UTP in the presence of Mg2+, Ca2+, Mn2+ and Co2+ with a pH optimum of 8.0, are sensitive to inhibition by mercurials, arsenicals, quercetin, proflavin and adenosine 5′-[γ-thio]triphosphate and are partially inactivated by exposure to high ionic strength. The kinetic behaviour is similar for all substrates irrespective of the source of material. The typical Eadie-Hofstee plot, which is concave upwards at pH 8.0 when the ionic strength is 20mM, becomes linear when the pH is increased to 8.5 or the ionic strength to 160mM. The overall evidence, particularly the labelling of only one polypeptide by [gamma-32P]ATP, suggests that under the conditions of preparation and assay used only one class of nucleoside triphosphatase active sites...
Biochemistry international, 1987
The effects of serum and cell density on the concentration of cyclic AMP, cyclic GMP in normal mo... more The effects of serum and cell density on the concentration of cyclic AMP, cyclic GMP in normal mouse fibroblasts cells (3T3 cells) and their Simian Virus 40 transformed derivative (SV3T3 cells) were studied. 3T3 cells grown in 10% foetal bovine serum exhibit density dependent inhibition of growth and associated with this in an increase in the concentration of cyclic AMP, a decrease in the concentration of cyclic GMP and an increase in the ratio (cyclic AMP/cyclic GMP) of the cyclic nucleotides. 3T3 cells grown in 10% newborn calf serum exhibit a higher saturation density and this is associated with a low concentration of cyclic AMP and a high concentration of cyclic GMP. SV3T3 cells grown in either 10% foetal bovine serum or 10% newborn calf serum show high saturation densities and this is associated with a low and decreasing concentration of cyclic AMP and a high concentration of cyclic GMP. When the level of the cyclic AMP in both cell lines was artificially raised by adding dibut...
Biochemical Medicine and Metabolic Biology, 1987
The 3T3 cells in culture exhibit density-dependent inhibition of growth (1) in opposition to the ... more The 3T3 cells in culture exhibit density-dependent inhibition of growth (1) in opposition to the simian virus-transformed 3T3 (SV3T3) cells which have the ability to grow to much higher densities (2). The density-dependent inhibition of growth is associated with decreases in the uptake of amino acid (3,4), phosphate (5-S), and glucose (9-12), while in the virus-transformed cells the uptake of these nutrients has been shown to be consistently high (3,5,13-l@. Since the transport of amino acid, glucose, and phosphate is a Na-dependent process (19-21), the maintenance of the sodium gradient across the cell membrane which is largely regulated by the Na-K pump is of importance in regulating cell growth. The activity of the Na-K pump in cultured cells has been shown by Aiton and Lamb (22) to be affected by serum concentration in the growth media. We have shown that sera types can also affect the activity of the Na-K pump in 3T3 cells (23) and also of several other membrane-bound enzymes (24). Since the 3T3 cells when first established were grown in medium supplemented with fetal bovine serum (l), while the SV3T3 cells were established in medium supplemented with newborn calf serum (2), we thought that the use of these two cell lines for comparing normal and malignant growth is only meaningful if the SV3T3 cells are grown in the same serum as that used in establishing the 3T3 cells. In this paper we report the effects of cell population density on the activity of Na-K pump and their roles in growth regulation in 3T3 and SV3T3 cells grown in medium supplemented with fetal bovine serum. Materials MATERIALS AND METHODS Swiss 3T3 and SV3T3 cells and materials needed for the growth of the cells which includes Dulbecco's modification of Eagle's minimal essential medium, fetal bovine serum, and trypsin were obtained from Flow Laboratories (Irvive,
Alimentary Pharmacology and Therapeutics, 1998
Biochemical Journal, 1979
The effect of 3′-deoxyadenosine (cordycepin) on mRNA efflux from isolated SV40-3T3 cell nuclei ha... more The effect of 3′-deoxyadenosine (cordycepin) on mRNA efflux from isolated SV40-3T3 cell nuclei has been studied and compared with its effect on the nucleoside triphosphatase activity in the isolated nuclear envelope. Inhibition of mRNA efflux occurs rapidly, but is dependent on the presence of ATP. Half-maximal inhibition occurs with 40 microM-cordycepin. The effect is not simulated by 2′-deoxyadenosine or by actinomycin D, and adenosine provides a substantial degree of protection against it. Cordycepin does not directly inhibit the nucleoside triphosphatase. The stimulation of this enzyme by poly(A) is not affected unless the poly(A) and cordycepin are incubated together with nuclear lysate in the presence of ATP; in this case the stimulation is significantly reduced. Possible interpretations of these results and their relevance for understanding the system in vivo for nucleo-cytoplasmic messenger transport are discussed.
Biochemical Society transactions, 1979
Journal of Cellular Physiology, 1985
Digestive and Liver Disease, 2005
Biochemical Society transactions, 1979