Days In Suspension Culture Research Articles

Interactions Among Phenolics and Peroxidase Isozymes

Peanut cells were grown for 14 days in suspension culture before the medium was collected as filtrate. Phenolic compounds were extracted from the medium by liquid-liquid partition technique. Two phenolic compounds, B and F (probably simple acids), were separated by paper chromatography. Isozyme A5, after association with phenolic F, was converted to an isozyme with the same Rm as A2. Isozyme A5 was converted to an intermediate form which, on attachment with a mixture of phenolics B and F, was converted to isozyme A4. A further linking of phenolics B and F to isozyme A4 converted them to an isozyme having the same Rm as isozyme A1.

The Regulation of Lipogenesis by Cyclic Nucleotides in Intact Hepatocytes Prepared by a Simplified Technique

Abstract An improved, simplified procedure is described for the isolation of liver cells from rat or chicken. Livers were perfused in situ and then incubated in a solution of collagenase and hyaluronidase. Greater than 50% of the liver mass was converted into a suspension of intact parenchymal cells which excluded a vital stain and were undamaged when viewed with the electron microscope. The cells actively incorporated labeled precursors into lipids and proteins without specific cofactor requirements in both simple, ionic, and complex culture media. The chicken hepatocytes synthesized lipids and proteins for several days in suspension culture, but suspended rat hepatocytes had minimal biosynthetic activity after 24 hours. Both dibutyryl cyclic AMP (0.1 mm) and adenosine 3' : 5'-monophosphate (cyclic AMP) (0.1 mm) produced a similar striking inhibition of [1-14C]acetate incorporation into lipids in chicken hepatocytes. Dibutyryl cyclic AMP was less inhibitory to lipid synthesis by rat liver cells and cyclic AMP had no effect on this process. The inhibitory actions of dibutyryl cyclic AMP were probably not due to isotopic dilution of the label within the cells. Neither cyclic nucleotide had a lipolytic effect in vitro on hepatocyte lipids prelabeled in vivo. The inhibitory action of dibutyryl cyclic AMP on lipogenesis was significantly greater than the effect of twice the concentration of sodium butyrate, and 5'-AMP did not diminish hepatic lipid synthesis. It is postulated that hepatic lipid synthesis is inhibited specifically by cyclic nucleotides, and that hormonal stimulation of adenylate cyclase regulates hepatic lipid synthesis.

Mucopolysaccharide synthesis by human bone marrow in short-term suspension cultures.

Abstract Human bone marrow cells were maintained for 2 days in suspension cultures. Cell counts were nearly constant, and cell morphology was well preserved over the 2 days. The myeloid/erythroid cell ratio remained constant. The percentage of mature cells increased in the erythroid series only. Both myeloid and erythroid cells were metabolically active. Autoradiographic studies showed that 35 S-sulfate labeled approximately half of the early myeloid cells and was not present in erythroid cells. The radioactivity was incorporated into mucopolysaccharide which was secreted into the medium, as well as contained in the cells. The mucopolysaccharide from both sources was associated with protein but could be isolated in a fraction identified chromatographically as chondroitin sulfate. Gel filtration studies indicated that the mucopolysaccharide from both cells and medium was polydisperse, and that the material secreted into the medium was of larger average molecular size than that remaining in the cells.

Rubella virus: continuous and concurrent production of complement-fixing antigen and infectious virus in suspension cultures.

Rubella complement-fixing (CF) antigen and infectious virus were produced continuously and concurrently for as long as 63 days in suspension cultures of BHK-21 cells prepared from uncloned monolayer stock cultures. CF titers ranged from 1:4 to 1:32, and the peak infectivity titer was greater than 8.0 (TCID(50) log(10)) per ml. Suspension cultures could be recultivated after prolonged storage in liquid nitrogen. The resulting monolayer or suspension cultures also produced CF antigen. Suspension cultures provide an effective system for the long-term continuous and concurrent production of rubella virus diagnostic reagents.

Rubella Virus: Continuous and Concurrent Production of Complement-fixing Antigen and Infectious Virus in Suspension Cultures

Rubella complement-fixing (CF) antigen and infectious virus were produced continuously and concurrently for as long as 63 days in suspension cultures of BHK-21 cells prepared from uncloned monolayer stock cultures. CF titers ranged from 1:4 to 1:32, and the peak infectivity titer was greater than 8.0 (TCID(50) log(10)) per ml. Suspension cultures could be recultivated after prolonged storage in liquid nitrogen. The resulting monolayer or suspension cultures also produced CF antigen. Suspension cultures provide an effective system for the long-term continuous and concurrent production of rubella virus diagnostic reagents.