Effect of Type of Carbohydrate on Growth and Protein Synthesis by Tetrahymena pyriformis

Abstract

SYNOPSIS. In chemically defined media at carbohydrate concentrations ≧ 0.5% (w/v) Tetrahymena pyriformis W multiplied more rapidly, developed larger cells, and achieved greater growth as measured by optical density when carbohydrate was provided as dextrin rather than glucose. In media containing 0.3 mg/ml of amino acid nitrogen, growth increased with glucose concentration from 0.1 to 1%, did not change significantly to 3%, and was sharply inhibited at higher glucose levels. With dextrin, maximum growth paralleled carbohydrate concentration from 0.1 to 3%. At higher N levels the inhibitory concentration of glucose was lowered, but growth in dextrin media was not affected except at N concentrations that were inhibitory independent of carbohydrate source. At 1% carbohydrate levels, total cell protein per ml of culture was 60% greater, protein per cell approximately 50% greater, and cells were 1.5 to 2 times larger in media with dextrin than with glucose. Comparable differences in protein synthesis were observed at 2% carbohydrate levels and efficiency of conversion of substrate‐N to protein‐N was greater in the medium with dextrin than glucose. Growth as measured by optical density in media with 0.3 mg/ml of N and 1 or 2% (w/v) of dextrin was not significantly reduced by the simultaneous presence of 1 or 2% glucose. This observation appeared to negate osmotic pressure as an explanation of reduced growth in the presence of glucose. At higher osmolar concentrations osmotic pressure appeared to be a major determinant of overall growth but not of cell size.

An Apparent Carbohydrate‐Amino Acid Interaction in Tetrahymena pyriformis

“…In rats and chicks, improved growth (1,9,10,15) and nitrogen utilization (30) have been observed when dietary sucrose was replaced by starch or dextrin. We have shown (19) that T . pyriformis also grows faster, achieves greater maximum growth, synthesizes more protein, produces larger cells, and under some conditions, converts medium nitrogen to protein nitrogen more efficiently when carbohydrate is supplied as a polysaccharide rather than as glucose.…”

“…Cells for experimental use were produced in 35 ml quantities of the same media in slanted milk dilution bottles. Preparation of cells for inoculum, growth studies, and other details of methodology were as previously described (19) except for protein-nitrogen estimation. The latter was based on culture optical density which I have shown earlier (18) to be closely correlated with cell protein but not with cell population under the conditions of these experiments.…”

“…Differences in growth of rats on polysaccharide versus sucrose diets have been observed only when nitrogen was supplied either by a poor quality protein or by high quality protein at growth limiting levels. In contrast, differences in growth of T. pyriformis as related to type of carbohydrate were essentially constant over nitrogen levels ranging from growth-limiting deficiencies to growth-inhibiting excesses (19). Furthermore, the associated difference in efficiency of nitrogen utilization increased with levels of exogenous nitrogen but was negligible at low nitrogen levels (18).…”

Carbohydrate Utilization by the Soil Amoeba Hartmannella castellanii

“…Sucrose, however, failed to support growth of 2 of the strains. Similarly Archibald & Manners(4) observed that cell-free extracts of Tetrahymena pyriformis hydrolyzed sucrose although it is not utilized for growth by this species (13). According to Lewin(9) a mutant of Chlumydomonas dysosmos oxidized acetate to CO2 and Ha, yet acetate did not support its growth.…”

Cultivation of the Peritrich Telotrochidium henneguyi in Axenic and Non‐Axenic Media*

“…An abundant supply of motile organisms was a\-ailable always from stock culture or from encysted telas which excysted promptly when stimulated to do so. The osmotic-shock method utilizing distilled water(4) was moderately successful in that it induced excystment of 50 to 70% oi the populations in 24 to 48 hr. Mechanical agitation induced excystmcnt of 90 to IMl% of the populations within [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] min: telas (encysted in a culture tube) were agitated by holding the tube in a I'ortex Jr. mixer (Scientific Industries, Inc.. Springfield.…”