Verdauungsphagocytose bei den Austern

Vonk, H. J.

doi:10.1007/bf00337914

Cited by 31 publications

(6 citation statements)

References 5 publications

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“…As already noted, cilia are never to be seen in sections (similar observations have been made on Ostrea by Carazzi (1896, 1897), MacMunn (1900), and Vonk (1924), nor have I observed them in fresh material; but in many Lamellibranchs (though never possible to see more than a border cuticle in sections), it is possible to see long cilia beating in the tubules when fresh material is examined, as Potts (1923) and I (1926) have shown. As will be shown later, there is a constant stream of food particles passing into the diverticula and of rejected particles passing out, and as there is no system of circular and longitudinal muscles such as ensures a similar circulation in the Crustacea (in which the diverticula are organs of both assimilation and secretion), there is strong presumptive evidence that cilia are present in the tubules of all Lamellibranchs.…”

Section: (C) Mouth and (Esophagussupporting

confidence: 67%

“…As a fesult of a study of previous work and as the outcome~of my own experirents, the conclusion was reached that the digestive diverticula are organs of absorption and of intracellular digestion, since they absorb soluble matter such as iron sulphate (Carazzi (1897) on Ostrea) or iron saccharate (Yonge (1926) on Nucula, Mya, and Teredo), and ingest solid matter sU9h as Indian ink (List (1902) on Mytilus, Potts (1923) on Teredo, Vonk (1924) on Ostrear, carmine (List on Mytilus) or blood corpuscles from dogfish (Yonge (1926) on Teredo). Sigerfoos (1908) and Potts have further shown that the Teredinidm ingest wood fragments in digestive diverticula specialised for that purpose.…”

Section: Assimination I Literature and Methodsmentioning

confidence: 86%

“…No experiments were carried out with Indian ink, the recent and conclusive work of Vonk (1924) on Ostrea having rendered them unnecessary. Animals were removed, and the various regions of the alimentary system fixed, at varying intervals after the commencement of feeding.…”

Section: Assimination I Literature and Methodsmentioning

confidence: 99%

“…Oysters after appropriate periods of starvation in water which had been passed through filter cloth were fed with suspensions in sea-water of iron saccharate, of blood corpuscles from dogfish, of a pure culture of the diatom Nitzschia, and with an emulsion of olive oil stained with Nile blue sulphate. No experiments were carried out with Indian ink, the recent and conclusive work of Vonk (1924) on Ostrea having rendered them unnecessary. Animals were removed, and the various regions of the alimentary system fixed, at varying intervals after the commencement of feeding.…”

Section: Assimilation I Literature and Methodsmentioning

confidence: 99%

“…Mucus laden with particles passes slowly along the oesophagus, particularly in the grooves at the extremities of the lumen, as described by Vonk (1924), into the stomach. Fig.…”

Section: In the Gutmentioning

confidence: 97%

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Structure and Physiology of the Organs of Feeding and Digestion inOstrea edulis

1926

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The anatomy and histology of the food collecting and alimentary organs of the adult oyster are described.The anatomy of the stomach is investigated with the aid of gelatin casts and attention drawn to the food caecum, the ventral groove, and the two ducts of the digestive diverticula.Cilia and mucus glands are universal throughout the food collecting and alimentary organs.There is evidence that the gastric shield is composed of fused cilia.The histology of the style-sac resembles that described by Mackintosh for Crepidula. There is evidence that secretion of the style takes place in the groove.Phagocytes are everywhere numerous in the blood vessels, connective tissue and epithelia, and free in the gut and mantle cavity.The alimentary organs of the larva are described.The anatomy and histology of these organs in the spat isdescribed, the palps are relatively large and the gills asymmetrical. The style-sac is distinct from the mid-gut.The course of the ciliary currents on the gills and palps is described and the importance of the various selective mechanisms emphasized.Selection appears to be purely quantitative, large particles or mucus masses being rejected and smaller ones accepted.Muscular activity is of great importance in the functioning of both gills and palps. Reversal of cilia has never been seen.Rejected matter is removed from the mantle cavity.Material is sorted in the food caecum in the stomach, larger particles passing into the mid-gut and smaller ones towards the gastric shield and ducts of the digestive diverticula, within the tubules of which there is a constant circulation.The rotation of the style assists in the stirring of matter in the stomach.In the style-sac are cilia, which rotate the style and others which push it into the storuach.In the larva the velum acts as a food collecting organ ; the style lies in an extension of the stomach and rotates rapidly. Material passes freely into the digestive diverticula.In the spat rejective mechanisms are highly developed. The style revolves at a speed of between sixty and seventy revolutions per minute.The tubules of the digestive diverticula are the only place where soluble matter is absorbed, in adult, larvae, or spat.Fine particles are ingested and digested intracellularly in the tubules of the digestive diverticula, the products of digestion carried away by amoebocytes, and useless matter rejected into the lumen.Larger particles are ingested and digested by phagocytes in all parts, the products of digestion being carried to the vesicular connective tissue cells and there stored.Enzymes in the style digest starch and glycogen. The amylase, at pH 5.9, has an optimum temperature of 43'C, and is destroyed atThe optimum medium is pH 5-9. It is inactivated by purification with absolute alcohol or by dialysis, but action is restored on the addition of chlorides or bromides and to a less extent iodides, nitrates, and carbonates, but not with sulphates or fluorides.Sucroclastic enzymes in the digestive diverticula act on starch, glycogen, sucrose, raffinose, maltose, lactose, salicin, and amygdalin, but not on inulin, cellulose, or pentosans.The amylase, at pH 5-5, has an optimum temperature of 44-5, and is destroyed at between 64 and 67. It has an optimum pH of 5-5, and is inactivated after purification or dialysis, action being restored in the presence of chlorides or bromides.There is a weak lipase and protease, the latter has two optima at pH 3-7 and at or above 9-0 ; its action is very slow.The only enzymes free in the stomach are those from the style.There is no evidence of any enzymes free in the gill mucus.There is a powerful complete oxidase system in the style, and a catalase in the digestive diverticula and gonad, and traces in the palps, gills, and muscle.The style is the most acid substance in the gut and the cause of the acidity of the gut.The style is dissolved rapidly in fluid of pH 2-3 and above, but very slowly below that point. It is readily dissolved and reformed in the oyster, its presence depending on the maintenance of the balance between the rate of secretion and the rate of dissolution. Its condition is a valuable indication of the state of metabolism.Glycogen and fat are stored, particularly in the vesicular connective tissue cells, the former furnishing the principal reserve food material.The presence of abundant supplies of microscopic plant life rich in carbohydrates provides ideal food for the oyster, and represents optimum conditions for fattening and reproduction.

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Section: (C) Mouth and (Esophagussupporting

confidence: 67%

Section: Assimination I Literature and Methodsmentioning

confidence: 86%

Section: Assimination I Literature and Methodsmentioning

confidence: 99%

Section: Assimilation I Literature and Methodsmentioning

confidence: 99%

“…Mucus laden with particles passes slowly along the oesophagus, particularly in the grooves at the extremities of the lumen, as described by Vonk (1924), into the stomach. Fig.…”

Section: In the Gutmentioning

confidence: 97%

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Structure and Physiology of the Organs of Feeding and Digestion inOstrea edulis

1926

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On the nature and action of diantlin; a new hormone‐like substance carried by the spermatozoa of the oyster

Nelson

Allison

1940

J. Exp. Zool.

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Digestion in Haliotis rufescens Swainson (Gastropoda: Prosobranchia)

McLean

1970

J. Exp. Zool.

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Digestion was studied in the marine archaeogastropod Haliotis rufescens, with emphasis on identification of absorptive regions in the gut. Extracellular enzymes were found i n the digestive fluid. Absorption in the digestive gland was demonstrated by autoradiography of tissue sections after feeding animals o n 14C-labeled algae. After absorption, food was retained apically in the absorptive cells of the digestive gland in an insoluble form. Possible mechanisms of uptake are discussed. It was shown chromatographically that small compounds derived from the food were present in both the crop fluid and blood early in digestion. Studies in vitro showed that the crop epithelium was permeable to small organic materials. Glucose and phenylalanine were found to have been taken up by the crop epithelium in considerable quantities; smaller amounts were passed through the epithelium, and would in life be transferred to the blood. The surface area of the food mass was seen to be increased in an intestinal sorting area at the beginning of the intestine. The intestinal epithelium was shown in vitro to be permeable to glucose. It is concluded that the large crop is an important region of absorption, and that digestion and absorption continue to occur as food passes along the intestine.

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Verdauungsphagocytose bei den Austern

Cited by 31 publications

References 5 publications

Structure and Physiology of the Organs of Feeding and Digestion inOstrea edulis

Structure and Physiology of the Organs of Feeding and Digestion inOstrea edulis

On the nature and action of diantlin; a new hormone‐like substance carried by the spermatozoa of the oyster

Digestion in Haliotis rufescens Swainson (Gastropoda: Prosobranchia)

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