Der Stoffwechsel von Ascaris lumbricoides bei Oxybiose und Anoxybiose

Brand, Th. v.

doi:10.1007/bf00713486

Cited by 41 publications

(6 citation statements)

References 9 publications

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“…T o other, larger parasites such as Fasciola hepatica and those which feed on intestinal contents, the supply of glucose is either sporadic or more restricted, and a higher energy yield per molecule may be essential. Many investigators have noted that the glycogen content of parasites in the blood and tissues is usually much less than that of those in the intestine (von Brand, 1966), where the parasites are normally subject to a diurnal rhythm in the availability of food, and may at times be deprived of nutrients, such as carbohydrates, for much longer periods. Glycogen, for example, comprises 6-70 yo of the muscle solids in A. lumbricoides , and 40-50% of the total solids in H. diminuta .…”

Section: ( 2 ) Fermentationmentioning

confidence: 99%

“…This is true for species such as Ascaris lumbricoides or adult tapeworms in which all evidence points to a fermentative type of energy metabolism. Although a number of investigators have provided evidence for the presence of Krebs cycle enzymes and electron transport systems (see von Brand, 1966;Read, 1968a;Vernberg, 1968;Saz, 1969, for reviews), almost no attention has been paid to their functional role. It cannot be said with certainty, for example, that the Krebs cycle plays an important part in the metabolism of a parasitic stage of any helminth, because well established criteria for establishing such a role (Saz, 1969) have not been applied.…”

Section: ( 2 ) Fermentationmentioning

confidence: 99%

“…Biochemical knowledge of helminth parasites (Platyhelminthes: Aschelminthes) is both reasonably detailed , 1 9 6 0~) 1969; Lee, 1965 ;von Brand, 1966; Read, 1966Read, , 1968a; Saz & Bueding, 1966; Smyth, 1966Smyth, , 1969; Rogers, 1969; Rothstein & Nicholas, 1969; Saz, 1969) and more than occasionally confusing. It is the purpose of this article to show that the concepts of adaptation and loss of genetic capacity not only contribute significantly to an improved understanding of present knowledge, but are also useful in the formulation of new experiments.…”

Section: Introductionmentioning

confidence: 99%

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Biochemical Adaptation and Loss of Genetic Capacity in Helminth Parasites

Fairbairn

1970

Biological Reviews

114

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Summary 1. Adaptation and loss of genetic capacity differ chiefly in that adaptation is goal‐ directed whereas loss of genetic capacity is not. Given sufficient information about an individual organism and its environment, adaptations are recognizable without reference to historical events extending beyond a single generation. This is not true of loss of genetic capacity, which requires a preliminary judgement that genetic information now absent was present in ancestral organisms. Together, adaptation and loss of genetic capacity are the major contributors to overall reproductive fitness. Accidental selection is genetically associated with adaptation, but is not goal‐directed. 2. Adaptations arevariant or invariant; invariant adaptations comprising biochemical unity, and variant adaptations contributing to biochemical diversity. Variant adaptations may be either exploitive or epigenetic. Exploitive adaptations are a measure of thegenetic capacity for phenotypic response to an altered environment, which the individual may not in fact encounter. Epigenetic adaptations are more rigidly programmed and are responsive to altered environments only insofar as these are a constant feature of the life cycle. 3. Selected observations in the biochemistry of helminth parasites are examined with respect to their interpretation in terms of adaptation, loss of genetic capacity and accidental selection. Secure judgements concerning adaptation are often possible at the most general level, i.e. when the physicochemical properties of the environment, such as temperature or oxygen supply, are clearly defined. I t is more difficult to make judgements concerning the specific mechanisms used in achieving these goals. Conclusions concerning loss of genetic capacity require knowledge of the specific function through‐out the life cycle. In many cases loss of genetic capacity is only apparent, as the function appears in another part of the life cycle. Such apparent losses are in reality epigenetic adaptations. These concepts are helpful in interpreting past work and in devising new experiments. 4. Development in helminth parasites includes a pronounced capacity for the orderly release of information to be used in the next stage. As each stage may require a radically different environment, programming for it may lead to phenomena which are superficially puzzling, such as the existence of aerobic electron transport systems in a stage whose energy metabolism is fermentative. The concept of epigenetic adaptation is especially useful for interpreting such observations. 5. Although possible adaptations are most readily apparent in biochemically complex mechanisms, these mechanisms are an expression of the orderly effects of many different primary gene products which have not been much studied. There are indications that organisms possessing relatively complex life cycles may provide opportunities for relating primary gene products, such as isozymes, to their physiological functions.

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Section: ( 2 ) Fermentationmentioning

confidence: 99%

Section: ( 2 ) Fermentationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Biochemical Adaptation and Loss of Genetic Capacity in Helminth Parasites

Fairbairn

1970

Biological Reviews

114

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“…i Sommer (1880) noted that the fluid in the excretory system of the adult Fasciola contains droplets, and Leuckart (1886-1901,p. 201),figures similar droplets in the larger vessels of the cercarial system, von Brand & Weinland (1925) found that these droplets dissolve in certain fat solvents, and are stained with Sudan III, Nile Blue sulphate and osmic acid. They concluded that the liver fluke excretes fat globules.…”

Section: Introductionmentioning

confidence: 96%

Physiological and histochemical observations on the adult liver fluke,Fasciola hepaticaL.

Stephenson

1947

Parasitology

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1. Careful search has failed to disclose the presence of flame cells in the excretory system of the adult liver fluke.2. Fat globules are produced in the walls of the excretory system, and are freed into the lumen, and thus to the exterior.3. These globules do not contain appreciable quantities of cholesterol, cholesterides or lipins, but may contain some unsaturated fatty material.4. The aqueous medium in which the globules float is either neutral or slightly alkaline.5. The distribution of reduced ascorbic acid has been investigated by the silver nitrate technique. This indicates that the main concentration occurs in the smaller vessels of the excretory system, and in the submuscular tissues of the body wall.

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“…Examples are the studies on the respiration of Ascaris by Krueger (1936Krueger ( , 1937 or of Triaenophorus by Harnisch (1933), the metabolic studies on Ascaris by Schulte (1917), von Brand (1934) or Oesterlin (1937), the studies on the overall and respiratory metabolism of Fasciola by Flury and Leeb (1926) or Weinland and von Brand (1926) and of Moniezia by von Brand (1929 and Cook and Sharman (1930). I refer to the fact that usually entire animals, but occasionally also minced materials were used to investigate some phase of the overall metabolism, but that no studies on the intermediate metabolism were carried out.…”

mentioning

confidence: 99%

Glimpses at the Early Days of Parasite Biochemistry

Brand¹

1972

Comparative Biochemistry of Parasites

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Der Stoffwechsel von Ascaris lumbricoides bei Oxybiose und Anoxybiose

Cited by 41 publications

References 9 publications

Biochemical Adaptation and Loss of Genetic Capacity in Helminth Parasites

Biochemical Adaptation and Loss of Genetic Capacity in Helminth Parasites

Physiological and histochemical observations on the adult liver fluke,Fasciola hepaticaL.

Glimpses at the Early Days of Parasite Biochemistry

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