Studies in the Chemical Dynamics of Animal Nutrition

Schryver, Samuel Barnett

doi:10.1042/bj0010123

Cited by 14 publications

(6 citation statements)

References 4 publications

(1 reference statement)

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“…PROTEIN REQUIREMENTS 81 (362), on the other hand, who examined the livers of fasting cats and those killed about five hours after a full meal, obtained results exactly contrary to those of Seitz.…”

Section: This Workermentioning

confidence: 89%

“…Hedin (177) and Cathcart (87) have both shown that the serum possesses active anti-proteolytic properties and that this anti-proteolytic action is associated with the albumin fraction, thus it may be that the increased autolysis in fasting is due in part to the disappearance of the serum albumin. Schryver (362), on the other hand, holds that the autolytic enzymes are held in check by purely chemical means. In a series of experiments he demonstrated that a diminution of the alkalinity of the tissues and fluids of the body from any cause was followed by an increase in proteolytic activity.…”

Section: The Physiology Of Protein Metabolismmentioning

confidence: 99%

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The physiology of protein metabolism

Cathcart¹

1912

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after absorption, could be used for rebuilding purposes, and which therefore might be regarded as a stage towards protein regeneration. They held that their view was strengthened by the fact that the increase of the excretion of nitrogen after the administration of leucine did not correspond with the amount of leucine fed, and further that an analogy existed in plant physiology where it was demonstrated that the decomposition products of protein, namely asparagine, leucine and tyrosine could be regenerated into protein when carbohydrate was also present. They suggested that a similar combination might occur in the liver of animals. Kutscher and Seemann (236) as the result of their experiments stated that they considered the above hypothesis very plausible, and concluded that the appearance of leucine and tyrosine, which they found, was the normal condition, and that these crystalline substances must be looked on as constituents, which, after absorption, would be utilized for the formation of tissue protein. They were unable to prove, however, that the hypothesis put forward by Salkowski and Leube was correct, as a series of experiments in which they performed a variety of Eck's fistula (cutting the liver out of the circulation), using a glass cannula for connexion between the portal vein and the vena cava, did not give decisive results.

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Section: This Workermentioning

confidence: 89%

Section: The Physiology Of Protein Metabolismmentioning

confidence: 99%

The physiology of protein metabolism

Cathcart¹

1912

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“…in 10 minutes. If we take Schryver's (7) figures of the protein nitrogen-content of 1 grm. of well-fed cat's liver as 22*4 mgrm.…”

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On the oxidation processes of the echinoderm egg during fertilisation

1922

Proc. R. Soc. Lond. B.

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The following paper is concerned with an investigation of the oxidation processes of the animal egg-cell during fertilisation. The subject has already received considerable attention and the problem has been approached from many different aspects. The first to attempt to measure in definitive quantitative manner the oxygen consumption of the egg on fertilisation, was Warburg(1) in 1908. He made use of the sea-urchin Arbacia , and estimated the amount of oxygen that had disappeared from the sea-water in which the eggs had remained for some time. The Winkler titration method was employed. He found that a quantity of eggs that gave a Kjeldahl determination of 28 mgrm. of egg nitrogen, which corresponds roughly to about 4 million eggs, 4—5 c. c. of oxygen was taken up in the first hour following fertilisation, while the same quantity of unfertilised eggs only consumed 0·5-0·7 c. mm. of oxygen in this time. The fertilised egg, therefore, took up six to seven times more oxygen than the unfertilised egg. Loeb had previously predicted, that the main function of the sperm in the process of fertilisation was that of setting up a series of oxidations on its entrance into the cytoplasm of the egg. Warburg’s work was a remarkable confirmation, therefore, of Loeb’s prediction. This first paper was followed up by a long series of papers which have added greatly to our knowledge of the oxidation processes taking place in the egg on fertilisation. In addition, our knowledge has also been greatly extended by the numerous papers of Loeb, and especially the papers of Loeb and Wasteneys (2) in which quantitative measurements were also carried out. In 1911 appeared the large paper of Meyerhof (3) in which the heat liberation was measured and correlated with the oxygen consumption. In all these papers the Winkler method was employed; there are, however, many drawbacks to the use of this method, and in the recent work of Warburg and Meyerhof it has been finally abandoned for the more convenient and accurate manometer. The great advantage of the manometer method lies in the fact that it can be used equally well for both oxygen and carbon dioxide determinations, and that continuous observations can be carried out minute by minute on the respiratory exchange of the material under investigation. Warburg (4) (1915), using this instrument, has recently reinvestigated the respiratory exchange in the egg of the sea-urchin Strongylocentvotus during the first 24 hours of development. He found that a quantity of unfertilised eggs that contained 20 mgrm. of egg nitrogen, which corresponds to about 3 million eggs, consumed in 20 minutes 10-14 c. mm. of oxygen at a temperature 23° C. and barometer 760 mm. Hg. The fertilised egg under the same conditions, 10 minutes after the addition of the sperm, consumed 60-84 c.mm. That is 10 minutes after fertilisation the oxygen consumption of the egg was six times that of the unfertilised egg, and that there was already a rise of 500 per cent, in the oxidation rate of the egg in this time. In the sixth hour the oxygen consumption was twelve times that of the unfertilised egg, at 12 hours it was sixteen times, while at 24 hours it was twenty-two times the amount of the unfertilised egg. As Warburg remarks, it is extraordinary that in one and the same cell substance, which receives no addition of fresh material from any external source, we should find, as the result of fertilisation in the course of 24 hours, a rise in its oxidation rate of something like 2000 per cent. On the whole the manometer method seemed to show that there was a much closer agreement between the increase in the respiratory quotient and the appearance of visible structure in the egg, than had been demonstrated in previous work where the Winkler titration method had been employed. In all instances the CO 2 output of the eggs followed closely the oxygen uptake, the respiratory quotient being in the neighbourhood of 0·9. The respiration of a single spermatozoon was found to be about 1500-2000 times less than that of the egg. In the past season, working at Naples, I have been able to carry the investigation of the problem a step farther, by the use of a special type of the Barcroft differential manometer, in which it was possible to bring about the fertilisation of the eggs in the closed chamber of the apparatus, and so for the first time the measurement of the respiratory exchange during the period the sperm were actually making their way into the egg was rendered possible. The eggs and sperm of Echinus microtuberculatus were used.

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“…Anhydrous sodium sulphate was employed for this purpose by Pinkus [1901] and Schryver [1906]; Rosenheim [1906] used the calcium salt. According to Frankel and Elfer [1910; anhydrous sodium phosphate is preferable both to sodium and calcium sulphates.…”

Section: On Allowingmentioning

confidence: 99%

Lecithin and Allied Substances—the Lipins.

1927

JAMA

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Studies in the Chemical Dynamics of Animal Nutrition

Cited by 14 publications

References 4 publications

The physiology of protein metabolism

The physiology of protein metabolism

On the oxidation processes of the echinoderm egg during fertilisation

Lecithin and Allied Substances—the Lipins.

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