Nereis Virens Research Articles

Uptake of Leucine by Larvae and Adults of Nereis

As part of an attempt to assess the importance of organic solutes as a food source for benthic animals, the uptake of carboxylic and amino-acids by the polychaete worm Nereis virens has been investigated1. Previous investigations1–3 have been concerned chiefly with the adult animals and it has been shown that the absorption process is an active one. The ratio of surface area to body volume of the animal is of obvious importance in any absorption process and it has already been demonstrated that uptake is faster in smaller than in larger animals4. Larvae might therefore be expected to show a very considerably enhanced rate of uptake.

Cellulase in Nereis virens.

IN their communication about direct uptake of organic solutes, Chapman and Taylor1 commented on the contradictory published accounts of the food and feeding of the polychaete Nereis virens Sars. Verrill2 stated that it is carnivorous, while Gross3 suggested that it is almost entirely herbivorous. Turnbull4 regarded the animal as omnivorous. The principal recognizable remains that we found in the guts of N. virens collected at Southend, Essex, were shells of the small gastropod Hydrobia, small fragments of small cockle (Cardium edule) shells, and the alga Enteromorpha intestinalis. When kept in aquaria, N. virens readily ate the flesh of cockles, mussels (Mytilus edulis), and shore crabs (Carcinus maenas), when these were placed near the entrances to the burrows. The shell-valves of cockles, approximately 5 mm in diameter, were broken by the jaws of the worms and ingested. Large cockles and mussels were eaten only when they died and gaped open. Moribund cockles and mussels occur in large numbers at Southend, resulting both from natural mortality and the activities of the “bait-diggers”, who accidentally bury these molluscs in their search for Nereis. Enteromorpha was also readily ingested, but it was observed during these experiments that the faecal pellets of the worms frequently contained strands of apparently undigested algae. This posed the question whether Nereis can digest the cell walls of algae which it has eaten or whether it can only utilize contents of cells broken mechanically.

Uptake of Organic Solutes by Nereis virens

WHILE investigating aspects of the trophic relationships of benthic animals, we have studied the uptake of amino-acids and other small organic molecules by the polychaete worm, N. virens, which lives in great numbers on the north side of the lower Thames Estuary1. Work on the isolation of possible organic solutes has already been reported2, and while no specific substances have yet been identified from surface water collected on Thames Estuary flats at Southend-on-Sea, other workers have reported the presence of quantities of organic material in sea water from various sources (for example, Duursma3).

The fine structure of the lens and photoreceptors of Nereis virens.

The cell membrane in the distal region of the photoreceptors of Nereis virens is formed into large numbers of tubular microvilli which interdigitate with those of neighbouring photoreceptors. No traces of cilia or basal bodies have been found, but a prominent axial filament with a repeat pattern of 660 A extends from the upper to the lower parts of the cell. Large numbers of mitochondria are found in the outer segment of the photoreceptors around the bases of the microvilli. As it passes through the pigment layer the photoreceptor is invaded by finger-like intrusions of the pigment cells which serve to prevent light entering the eye from behind. The lens consists of fine filaments or rod-shaped bodies secreted by the pigment cells, which pass to the lens up narrow pillars between the outer segments of the photoreceptors. Attention is drawn to the evolutionary parallel between the shadow reflex of Branchiomma and the “off” responses of the photoreceptors in the distal retina of Pecten, both animals being exceptional within their phyla in having photoreceptors of the ciliary type.

Segmental musculature and parapodial movement of Nereis diversicolor and Nephthys hombergi (Annelida: Polychaeta)

The segmental musculature of Nereis diversicolor O. F. Müller is described. The musculature of Nereis irrorata (Malmgren), Nereis fucata (Savigny) and Neanthes virens (Sars) is essentially similar but comparison with Perinereis cultrifera (Grube) shows that, at least as far as the oblique muscles are concerned, the segmental musculature of all members of the Nereidae is not identical. A comparison is made with the musculature of Nephthys hombergi (Audouin & Milne Edwards). Swimming in Nereis and Nephthys is achieved by waves of lateral undulation passing from tail to head with associated parapodial deflection. The promotor and remotor muscles of the parapodium are the ventral parapodial obliques inserting at the parapodial base on anterior and posterior faces. This point of insertion is the hinge line of the parapodium. The dorsal parapodial muscles of Nephthys are more complex than in Nereis, apparently associated with the divergent parapodial rami of the former.In slow creeping, intrinsic muscles of the parapodium of Nereis raise it from the substratum and direct it forward, drawing in the neuropodium. Acicular muscles are responsible for its backward extension. The extended notopodium is a firm base for further protraction of the neuropodium. These muscles in Nephthys are modified for burrowing; the parapodia help to stabilize the body during proboscis eversion. Acicular muscles extend the parapodial rami dorsolaterally and ventrolaterally to grip the sides of the burrow. Intrinsic muscles withdraw the notopodial and neuropodial tips.The septum of N. diversicolor is not reduced in the typical body segment and its muscle fibres penetrate the dorsal longitudinal muscle to insert into the circular muscle layer. The pseudoseptum of Nephthys is probably homologous with that of Glycera and Phyllodoce and correlated with possession of a long, eversible proboscis.The complexity of oblique muscles in Nereis throws doubt on their alleged polyneuronal innervation. Muscular division of labour in slow and fast parapodial movements is proposed as an alternative to innervation by fast and slow fibres.

Étude de la coque d'une soucoupe plongeante de grande profondeur. Détermination des contraintes localisées de part et d'autre de l'ouverture (coque et porte). Recherche du profil de renfort : Levy-Soussan Guy et Albano Trombetta, 1965. Bull. Inst. océanogr., Monaco, 62 (1300): 124 pp.

At the water–sediment interface of aquatic ecosystems, the presence of biogenic structures produced by benthic invertebrates strongly affects biogeochemical processes. The quantification of these structures and the assessment of the vertical distribution of fauna are essential for determining the impact of communities in sediments. In the present study, computer axial tomodensitometry (CAT-scan) was used to measure the space occupied by an intertidal community of the St. Lawrence estuary. Three cores were sampled at a site that was considered homogeneous according to surface sediments. The vertical distribution of biogenic structures and gravel were measured in the three cores using CAT-scan; the vertical distribution of fauna was also analysed for each core. The biogenic structures were highest at the water–sediment interface and decreased with depth in the three cores. The number of invertebrates also decreased with depth. We observed similar distributions of biogenic structures in cores 1 and 2. However, fewer biogenic structures were observed below 90 mm in core 3. This result was correlated with a high quantity of gravel from 90 to 140 mm in core 3 whereas the other cores had lower quantities of coarse material. We found relationships among the distributions of biogenic structures, fauna, and sediment characteristics (gravel quantity) that can affect species distribution. The vertical distributions of Macoma balthica, Mya arenaria, Nereis virens, and small-sized gallery-producing species (nematodes and oligochaetes) could also be recorded with the CAT-scan method. Thus, CAT-scan is an excellent tool to determine the fine-scale heterogeneity in the space occupied by benthic invertebrates in sediments.

The localisation of succinic dehydrogenase in the muscles of Nereis Virens and Homarus Gammarus.

The localisation of succinic dehydrogenase and cytochrome oxidase in body muscles of Nereis virens and in tail muscles of Homarus gammarus was studied. Pig heart muscle was used for some comparisons.

The Motor Axon Terminations of Annelids

PREVIOUS work on the histology of the peripheral nerves of annelids has failed to reveal the nature of the termination of the motor axons on the muscle fibres. Retzius1 and Smallwood2 both described the motor axons of Lumbricus as ending simply with small swellings on the surface of the muscle fibres after producing a few lateral branches. Smallwood described a second type of ending which may be similar to those presented here, but his figure is inadequate. Fig. 1 is a photograph of a methylene blue preparation of Nereis diversicolor showing the termination of three motor axons on the parapodial levator muscle. They are located in the dorsal region of the parapodium where the fibres of this muscle originate on the connective tissue underlying the epidermis. I have also found similar endings in this position in Nereis virens. Each axon divides into a cluster of 15–20 end plates and transverse sections of the preparation showed that these were on the surface of a small group of muscle fibres. The endings (Fig. 2) are similar to the grape type shown by Gray3 to occur on the tonic muscle fibres in the frog. If the simple type of termination described by Retzius represents a true functional ending, the occurrence of a second type is of great interest in view of the evidence put forward by Horridge4 and Wilson5 for fast and slow systems of muscular contraction. It suggests the possibility that each type of muscular response may be mediated through morphologically distinct endings.

Behaviour of the polychaete Nereis in T-mazes

Summary 1. Individuals of Nereis virens, N. diversicolor and Perinereis cultrifera were unable to learn to avoid a punishment in a ‘T’ maze consistently if the arm which avoided the punishment led straight out of the maze. An initial series of random choices was usually followed by an improvement in performance but then a return to random behaviour and finally refusal to crawl through the maze. 2. If selection of the arm which avoided the punishment was reinforced by a period in a darkened chamber individuals of the same three species were able to learn to choose this arm consistently. 3. Worms which had learnt to avoid the punishment reverted to more variable behaviour after decerebration. Naive, decerebrate Nereis virens were unable to learn to choose one arm of the maze consistently.

Responses of nereis virens to alcohols

1. 1. Clamworms, Nereis virens Sars, respond to chemical stimulation in a quantitative manner while housed in glass tubes. 2. 2. Acceptance and rejection responses were distinguishable and were found to occur, as a function of concentration, upon stimulation with Mytilus extract, amino acids and alcohols. 3. 3. Median rejection concentrations and concentrations at maximal acceptance were determined for a series of nine saturated monohydric alcohols.

The precipitation reaction between the fertilizin of the ova and the antifertilizin of the spermatozoa in polychaeta of the white sea

The author studied the precipitation reaction between solutions of fertilizin of the ova and antifertilizin of the spermin Nereis virens andArenicola marina.

THE MORPHOLOGY AND LIFE HISTORY OF THE DIGENETIC TREMATODE, ZOÖGONOIDES LAEVIS LINTON, 1940

Previous articleNext article No AccessJournal ArticlesTHE MORPHOLOGY AND LIFE HISTORY OF THE DIGENETIC TREMATODE, ZOÖGONOIDES LAEVIS LINTON, 1940HORACE W. STUNKARDHORACE W. STUNKARD Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Biological Bulletin Volume 85, Number 3December 1943 Published in association with the Marine Biological Laboratory Article DOIhttps://doi.org/10.2307/1538224 Views: 12Total views on this site © 1943 Marine Biological LaboratoryPDF download Crossref reports no articles citing this article.

STUDIES ON DEROPRISTIS INFLATA (MOLIN), ITS LIFE HISTORY AND AFFINITIES TO TREMATODES OF THE FAMILY ACANTHOCOLPIDAE

The life history of Deropristis inflata has been demonstrated experimentally. The cercaria is a trichocercous form developing in simple rediae in the marine snail, Bittium alternatum. It enċysts in Nereis virens and the eel, Anguilla rostrata serves as the natural definitive host which becomes infected by eating annelids containing metacercariae.The genus Deropristis and Dihemistephanus sturionis are excluded from the family Acanthocolpidae which is redefined to include for the first time the genera Lepidauchen, Pleorchis, and Pseudolepidapedon. The family Pleorchiidae thereby becomes invalid.It is proposed that the family Allocreadiidae be restricted to include only forms known or believed likely to have ophthalmoxiphidiocercariae with main excretory tubules not reaching the cephalic region of the body before receiving secondary tubules. The Allocreadiidae and Acanthocolpidae are regarded as separate but closely related families.The genus Anallocreadium is reduced to synonymy with Homalometron and the su...

STUDIES ON INVERTEBRATE HEMOGLOBINS (ERYTHROCRUORINS)

1. Two high molecular invertebrate hemoglobins (the erythrocruorins of Lumbricus terrestris and of Nereis virens) as well as the low molecular erythrocruorin of Glycera dibranchiata Ehlers were studied. Their physical chemical properties were compared with those of vertebrate hemoglobin. 2. The hemin of the blood pigment of Glycera dibranchiata Ehlers was shown to be identical with that of vertebrate hemoglobin. 3. The dissociation rates of Glycera and human oxyhemoglobin were measured in the reaction meter of DuBois and t(50) (half time of the reaction) was found to be identical (0.027 second) for the two pigments. The t(50) value for the high molecular Lumbricus erythrocruorin was 0.070 second. 4. The chemical constitution and physical chemical properties of erythrocruorins were compared with those of vertebrate hemoglobin and of hemocyanin.

THE EFFECTS OF SALINITY CHANGES ON BODY WEIGHT AND SURVIVAL OF NEREIS VIRENS

1. Nereis virens increased in weight on transfer to sea water diluted with fresh water. This increase was greater the greater the dilution. 2. The minimum survival concentration was between 30 and 40 per cent sea water. In concentrations of greater salt content than this, N. virens decreased in weight after the initial increase. This decrease was rapid for about a day and then gradual. 3. A few scattered observations of body weight changes which seemed to be associated with temperature changes have been made. These are in agreement with the report of Adolph, E. F. and P. E. (1925). 4. On return to sea water from a dilution, N. virens lost weight rapidly. This loss was greater the lower the concentration in which the animal had been kept. After this initial loss a slight increase in weight occurred. 5. When specimens of N. virens were placed for a second time in their respective dilutions they increased in weight again. This time, however, the changes were more gradual and smaller than those after the first subjection to dilutions. 6. Although N. virens survived but a few hours after direct transfer to 1/8 sea water, it lived 14 days in that dilution when transferred slowly through intermediate dilutions. 7. Worms which had been several days in dilute sea water lived in fresh water longer than did worms which had been transferred directly from ordinary sea water. Also the more dilute the solution in which the animal had been kept the less the rise in weight on transfer to fresh water.

OBSERVATIONS ON CERCARIÆUM LINTONI MILLER AND NORTHUP AND ITS METACERCARIAL DEVELOPMENT

The description of Cercariæum lintoni Miller and Northup as given by earlier workers is supplemented and emended in the light of knowledge obtained by comparing the cercariæum with its metacercarial stage, developed in experimental animals. The true nature of the digestive and reproductive systems is made clear.Cercariæum lintoni penetrated the parapodia of Nereis virens, encysted, and developed into the metacercarial stage. Although the cercaria would penetrate and encyst in other invertebrates, the clam worm was the only form in which development was secured. Nereis virens appears to be a natural host. The metacercaria develops adult features as the larval characters disappear.It is difficult to determine the relationship of this species to other trematode groups; the digestive system is similar to that of the species of the family Haploporidæ, but the arrangement of the reproductive organs is very different and resembles that of the Zoogonidæ. palombi's suggestions concerning the relations of the species are discussed.

Relation of oxygen tension to oxygen consumption in Nereis virens

Relation of oxygen tension to oxygen consumption in Nereis virens

The influence of the nervous system on regeneration in Nereis virens, Sars

Journal of Experimental ZoologyVolume 60, Issue 4 p. 485-509 Article The influence of the nervous system on regeneration in Nereis virens, Sars Gladys Elizabeth Holmes, Gladys Elizabeth Holmes Hunter College of the City of New York This paper comprises parts of a thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Brown University. The problem was undertaken at the suggestion of Prof. J. W. Wilson, at the Marine Biological Laboratory at Woods Hole, Massachusetts, 1928 and 1929, and at the Arnold Biological Laboratory, Brown University, Providence, Rhode Island, 1928 and 1929. I wish to express my appreciation and gratitude for the advice and encouragement of Professor Wilson during the progress of this investigation.Search for more papers by this author Gladys Elizabeth Holmes, Gladys Elizabeth Holmes Hunter College of the City of New York This paper comprises parts of a thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Brown University. The problem was undertaken at the suggestion of Prof. J. W. Wilson, at the Marine Biological Laboratory at Woods Hole, Massachusetts, 1928 and 1929, and at the Arnold Biological Laboratory, Brown University, Providence, Rhode Island, 1928 and 1929. I wish to express my appreciation and gratitude for the advice and encouragement of Professor Wilson during the progress of this investigation.Search for more papers by this author First published: November 1931 https://doi.org/10.1002/jez.1400600404Citations: 9 This paper comprises parts of a thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Brown University. The problem was undertaken at the suggestion of Prof. J. W. Wilson, at the Marine Biological Laboratory at Woods Hole, Massachusetts, 1928 and 1929, and at the Arnold Biological Laboratory, Brown University, Providence, Rhode Island, 1928 and 1929. I wish to express my appreciation and gratitude for the advice and encouragement of Professor Wilson during the progress of this investigation. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume60, Issue4November 1931Pages 485-509 RelatedInformation

An apparent conditioned response in Nereis virens.

An apparent conditioned response in Nereis virens.

THE CHEMICAL SENSE AND FEEDING BEHAVIOR OF NEREIS VIRENS. SARS

1. Nereis virens is carnivorous, although in the absence of other food it has been observed to feed upon sea lettuce. Under natural conditions it undoubtedly is omnivorous, since Gross has found evidence of the presence of plant food in the digestive tract. 2. Nereis was never observed to leave its burrow when baited with meat of various marine animals, but it may expose all except the posterior segments of its body in reacting to the bait. This does not mean that the worm may not leave its burrow under other circumstances. The animal is highly thigmotactic. 3. There is positive evidence that Nereis depends upon a chemical sense in finding animal food; sight playing little if any part in the act. Currents in the burrow produced by an undulatory body movement are undoubtedly a factor in conveying food stimuli to the sense organs. 4. Nereis shows a marked tendency to extend its body from the burrow in the direction of food, and failing to reach it, to reappear in a new position nearer the source of the stimulating material.