The Biochemistry of Ciliates in Pure Culture

Kidder, George W.; Dewey, Virginia C.

doi:10.1016/b978-1-4832-3139-6.50011-2

Cited by 135 publications

(59 citation statements)

References 80 publications

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“…same reactions by the bacteria. Ammonia production in particular appeared to occur by different mechanisms in the bacteria and the protozoa, and it is suggested that much of the continuing ammonia production in the rumen in the absence of readily attacked protein might be due to the endogenous metabolism of rumen protozoa; ammonia is known to be the major end product of nitrogen metabolism in some freeliving ciliate protozoa (Kidder & Dewey, 1951). El-Shazly (1952b) found that the capacity of rumen bacteria to deaminate amino acids depended on the prcsence in the diet of the host animal of a readily attacked protein.…”

Section: Discussionmentioning

confidence: 99%

Proteolysis by Rumen Micro-organisms

Warner¹

1956

Journal of General Microbiology

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SUMMARY : Toluene-treated washed suspensions of rumen bacteria break down proteins largely to amino acids ; in the absence of toluene bacterial deaminases are active. Unlike the deaminases, the presence of proteases does not depend, to any great extent, on the presence of readily attacked protein in the diet of the host animal. Extracts of acetone-dried powders of the bacteria also show proteolytic activity. Rumen protozoa are also proteolytic, and ammonia appears to be the end product of their nitrogen metabolism. Ammonia production due to the protozoa is not as sensitive to toluene as is the case with bacteria. Much of the ammonia production in the rumen in the absence of substrate appears to be due to the endogenous metabolism of the protozoa. Extracts of acetone powders, and extracts prepared by simple freezing and thawing of the protozoa, contain active proteases.In an artificial rumen apparatus it was shown that when digestion was complete, about half the N and C of added casein could be recovered as ammonia and volatile fatty acids respectively. Most of the remainder could not be accounted for analytically, and was presumed to be used for microbial growth, which had occurred. When starch or some other polysaccharides were added to the artificial rumen apparatus as well as casein, the production of ammonia was lowered. This was shown not to be due to any effect on proteolysis or deamination, and was presumed to be due to the increased utilization for microbial growth of some breakdown product of casein.From a t least the time of Zuntz (1891), it has been suspected that microorganisms of the rumen split the proteins fed to the host animal; there has been, however, little unequivocal direct evidence for this proteolytic activity. Schlottke (1936) showed in vitro that glycerol extracts of rumen protozoa contained a protease active a t pH c. 6.1, and also a dipeptidase, but was unable to find much activity in glycerol extracts of rumen bacteria. However, Sym (1938) showed active proteolysis a t pH 6.3 by suspensions of rumen bacteria and of protozoa, and also by extracts of acetone powders of these microorganisms; he found peptidase activity weak in his preparations. Both these authors found little or no free protease in the supernatant rumen liquor. Nikitin (

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Section: Discussionmentioning

confidence: 99%

Proteolysis by Rumen Micro-organisms

Warner¹

1956

Journal of General Microbiology

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“…(Wilson Laboratories, Chicago, Illinois). Sulphates and chlorides were added as in the basal medium A of Kidder & Dewey (1951). In more recent experiments, the only inorganic salt added was 0.1 */* (w/v) K,HPO,.…”

Section: Methodsmentioning

confidence: 99%

Glyconeogenesis in Growing and Non-growing Cultures of Tetrahymena pyriformis

Lévy¹,

Scherbaum²

1965

Journal of General Microbiology

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SUMMARYThe glycogen content of peptone grown cultures of the ciliate Tetrahymena pyriformis GL, increased from 6 % cellular protein during the exponential growth phase to 30 yo or more in the stationary phase of growth.The oxygen content in the medium began to decrease at a population of 7500 organisms/ml. in gently shaken cultures and a t 80,000 organisms/ ml. in well aerated cultures. In either case, depletion of oxygen in the medium was soon followed by cessation of multiplication. The stationary phase was rapidly induced by transfer of log phase organisms to conditions of restricted aeration. Within 3 hr after such a transfer, the rate of glyconeogenesis approximately doubled, both in cultures and in washed suspensions of organisms incubated with 0.1 yo sodium acetate.

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“…In fungi and bacteria greater and varying degrees of heterotrophy are to be found; they are exemplified by specific requirements for one or more amino-acids (Snell, 1951). But it is in animals (ciliates, insects, vertebrates) that nitrogen heterotrophy has proceeded farthest and become so stereotyped that it is possible to speak of the 'ten amino acids essential for protein synthesis' with little ambiguity (Kidder & Dewey, 1951;Trager, 1953;Rose, 1938). Against this background the mere inability to reduce nitrate would seem not to remove Oxyrrhis very far from the higher green plant.…”

Section: I I I I I I I I I Imentioning

confidence: 99%

“…However, a great many chlorophytes are oxytrophic in the dark while many others, including isolated tissues of phanerogams, utilize carbohydrate as well and to that extent may be regarded as being haplotrophic (Provasoli, 1938;Algeus, 1946;White, 1951;Pringsheim, 1952;Lewin, 1953). Although the number of possible substrates is even greater in animals such as ciliates, insects and vertebrates, so it is also in some fungi and bacteria (Kidder & Dewey, 1951;Trager, 1953;Albritton, 1954;Foster, 1949;Stephenson, 1949). Acetate organisms are thus characterized by limitations which they share with neither animals nor higher plants.…”

Section: I I I I I I I I I Imentioning

confidence: 99%

Water-soluble factors in the nutrition ofOxyrrhis marina

Droop

1959

J. Mar. Biol. Ass.

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Oxyrrhis marina Dujardin is a non-photosynthetic dinoflagellate whose obvious mode of nutrition is phagotrophy. The method of feeding was described by Barker (1935). It is an extremely euryhaline and hardy organism and is apparently very successful in brackish habitats such as supralittoral rock pools and ditches (Droop, 1953 a). Owing to the ease with which it can be cultivated Oxyrrhis is a choice for the initial study of phagotrophy among the predominantly plant-like Dinoflagellata.

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The Biochemistry of Ciliates in Pure Culture

Cited by 135 publications

References 80 publications

Proteolysis by Rumen Micro-organisms

Proteolysis by Rumen Micro-organisms

Glyconeogenesis in Growing and Non-growing Cultures of Tetrahymena pyriformis

Water-soluble factors in the nutrition ofOxyrrhis marina

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