The mechanism of boring in Zirphaea crispata (L.) (Bivalvia: Pholadidae)

1968 ◽  
Vol 170 (1019) ◽  
pp. 155-173 ◽  
Keyword(s):  
Adductor Muscle ◽  
Mantle Cavity ◽  
Clockwise Rotation ◽  
Mantle Tissue ◽  
Counter Pressure ◽  
Time Period ◽  
Adductor Muscles ◽  
Inhalant Siphon ◽  
Main Activity ◽  
Low Pressures

The main activity during boring by Zirphaea crispata consists of the cyclical repetition of a group of movements, termed the boring cycle. Each boring cycle comprises the retraction of the shell to the base of the burrow, and the abrasion of the walls of the burrow by movements of the shell caused by the consecutive action of the posterior and anterior adductor muscles, supplemented by an accessory ventral adductor muscle. Each boring cycle is followed by slight anticlockwise and clockwise rotation of the animal in the burrow, while simultaneously the siphons are withdrawn and re-extended. A second type of rotational movement, resulting from changes in the position of the foot in the burrow, occurs over a longer time period, so that a circular, drop-shaped burrow is formed. The material abraded from the base of the burrow is collected into the mantle cavity and ejected as pseudofaeces from the inhalant siphon at intervals during boring. The pressures developed in the mantle cavity and haemocoele during boring are small compared with those generated by burrowing forms. During the boring cycle, low pressures (2 to 3 cm) serve to press the foot against the wall of the burrow where adhesion is aided by mucous secretion and by the action of a counter pressure from a pad of mantle tissue dorsally. Fluid is retained in the foot, and in the expanded mantle margins within the spaces of a loosely arranged connective tissue which fills these organs. The fluid filled mantle cavity and haemocoele allow the siphonal retractor muscles to act partly in antagonizing the adductor muscles, so that withdrawal of the siphons during boring restores the gape of the shell. Higher pressures (8 cm) are developed in the mantle cavity and haemocoele during the contraction of the adductor muscles and circular muscles of the siphons which is involved in the expulsion of pseudo-faeces. The tensions exerted by the pedal muscles during boring are small (2 to 2·5 g).

The mechanisms of boring in Martesia striata Linné (Bivalvia: Pholadidae) and Xylophaga dorsalis Turton (Bivalvia: Xylophaginidae)

1969 ◽  
Vol 174 (1034) ◽  
pp. 123-133 ◽  
Keyword(s):  
Cross Section ◽  
Circular Cross Section ◽  
Mantle Cavity ◽  
Body Fluids ◽  
The Body ◽  
Clockwise Rotation ◽  
Faecal Pellets ◽  
Adductor Muscles ◽  
Inhalant Siphon ◽  
Wood Boring

Penetration of timber by the wood-boring bivalves Martesia striata and Xylophaga dorsalis is effected by means of the cyclical repetition of a group of movements termed the boring cycle. In Martesia the boring cycle comprises first the retraction of the shell to the base of the burrow, followed by the abrasion of the wall of the burrow by movements of the shell caused by a single consecutive contraction of each of the adductor muscles. In Xylophaga similar movements are involved, but the boring cycle in this species has become elaborated by repetition of the contractions of the adductor muscles which may be repeated to give a series of up to 24 rocking movements of the shell about a dorso-ventral axis. In both species the boring cycle may be followed by movements involving anti-clockwise and clockwise rotation in the burrow, while simultaneously the siphons are partially withdrawn and re-extended; in both, longer term rotations in the burrow result in the production of a drop-shaped burrow of circular cross-section. In both species the material abraded from the base of the burrow is collected into the mantle cavity; in Martesia it is then ejected as pseudofaeces through the inhalant siphon at intervals during boring, while in Xylophaga a larger proportion passes into the gut and eventually collects in the form of faecal pellets to form a plug to the burrow. The pressures developed in the mantle cavity and haemocoele during boring are small compared to those in burrowing forms, but of the same order as those recorded from the related rock-boring pholad Zirphaea crispata , and it is concluded that the body fluids play a decreasing hydraulic role as specialization for boring increases.

scholarly journals The adductor mechanism of pecten

1930 ◽  
Vol 106 (745) ◽  
pp. 363-376 ◽  
Keyword(s):  
Skeletal Muscle ◽  
Adductor Muscle ◽  
Mantle Cavity ◽  
Slow Muscle ◽  
The Other ◽  
Muscular Tissue ◽  
Rhythmic Movements ◽  
Adductor Muscles ◽  
Closed Position ◽  
Von Uexküll

The adductor muscles of most lamellibranchs fulfil two functions, first the closing and keeping closed of the valves in response to unfavourable or noxious stimuli, and second occasional partial closure while the animal is respiring and feeding and not strongly stimulated. This last is supposed to be a means of cleaning out the mantle cavity. In Pecten and a few allied forms the adductor mechanism has been modified for swimming by means of rapid rhythmic movements of the valves. The mechanics of the swimming process have been described by Buddenbrock (1). The movements are brought about by the large single adductor muscle (posterior adductor) situated nearly centrally between the valves. Like the adductors of most lamellibranchs the muscle is composed of two easily distinguished parts. The larger part is yellowish and translucent in appearance, of very soft consistency and composed of striated fibres. It is responsible for the rapid flapping movements of swimming. The other part, which generally constitutes less than 10 per cent, of the total weight of muscular tissue, is white and opaque in appearance, much tougher in consistency, and composed of unstriated fibres. It is the part which is responsible for keeping the valves closed, and has been called the “catch” muscle (sperrmuskel, von Uexküll) (2). The two portions of the adductor muscle will be referred to as the large or quick and the small or slow respectively. If one attachment of the slow muscle is severed without other injury to the animal and the quick muscle is stimulated reflexly, by touching the mantle, rapid flapping movements are obtained just as in the intact animal, but the valves cannot be kept in the closed position against the tension of the elastic ligament of the hinge for more than a few seconds. As soon as excitation ceases the valves gape. If, on the other hand, the quick muscle is severed, leaving the slow, the only reaction obtained with the whole animal is a slow closure of the valves which may continue for some time. These phenomena have long been known (Bronn (3), Coutance (4) ). Biedermann (5) in 1885, described what is evidently the twitch of the slow adductor muscle of Anodonta but did not consider it a twitch, apparently because it was several hundred times slower than that of frog’s skeletal muscle (Biedermann (6), vol. 1, pp. 178, 187). Pavlov (7), however, recognised the nature of the response of Anodonta muscle. Prior to the recent work on the mechanical properties of muscle (Gasser and Hill (9), Hill (8), Levin and Wyman (10) ), it was evidently difficult for observers to realise that the same fundamental change might underlie such an enormous difference in time scale, a difference due in part at least to differences in the viscous-elastic constants of the tissue. From the experiments to be described it is concluded that the most important difference between the slow muscle of Pecten and vertebrate skeletal muscle is a matter of “viscosity.”

Rapid shell closure in the brachiopods Terebratulina retusa and Terebrataua transversa

1992 ◽  
Vol 72 (3) ◽  
pp. 579-598 ◽  
Author(s):  
Spafford C. Ackerly
Keyword(s):  
Detailed Analysis ◽  
Hydrodynamic Model ◽  
Puget Sound ◽  
Muscle Length ◽  
Adductor Muscle ◽  
Muscle Physiology ◽  
Shell Closure ◽  
Functional Architecture ◽  
Adductor Muscles ◽  
Kinematic Properties

Rapid shell closure in articulate brachiopods, occurring by a twitch contraction of the the ‘quick’ adductor muscles, is a response to disturbance or to physiological requirements of the organism. The relative simplicity of the closing system permits a detailed analysis of the functional architecture of the mechanism and the underlying principles of skeleto-muscular organization, in terms of (1) basic kinematic properties of the system (speeds and times of closure), (2) hydrodynamic reactions resisting closure, and (3) considerations of muscle physiology and mechanics.Analyses of shell closure in the brachiopods Terebratulina retusa from the Firth of Lorn, Scotland, and Terebratalia transversa from Puget Sound, USA, reveal (1) shell-closing times of the order of 50 to 70 ms, (2) closing velocities of the order of 3·5 radians s-1, from initial gapes of about 0·05 to 0·2 rad, and (3) muscle moment forces and hydrodynamic reactions with magnitudes of the order of 5 × 10-4 N m (5 g cm). Muscle tensions developed in the ‘quick’ adductor muscle are of the order of 105 N m2, and contraction velocities are of the order of one muscle length per second. Hydrodynamic reactions are a fundamental constraint on the closing mechanism, as determined by the concordance of actual closing events with predictions of a hydrodynamic model.

scholarly journals Ultrastructure of phagocytes and oocysts of Nematopsis sp. (Apicomplexa, Porosporidae) infecting Crassostrea rhizophorae in Northeastern Brazil

2019 ◽  
Vol 28 (1) ◽  
pp. 97-104
Author(s):  
Themis Jesus Silva ◽  
Emerson Carlos Soares ◽  
Graça Casal ◽  
Sónia Rocha ◽  
Elton Lima Santos ◽  
...  
Keyword(s):  
Parasitophorous Vacuole ◽  
Adductor Muscle ◽  
Systematic Position ◽  
Variable Number ◽  
Northeastern Brazil ◽  
Ultrastructural Organization ◽  
Oocyst Wall ◽  
Transmission Electron ◽  
Adductor Muscles ◽  
Crassostrea Rhizophorae

Abstract This work describes the detailed ultrastructural morphology of the phagocyte imprisoning an oyster of Nematopsis (Apicomplexa) found in Crassostrea rhizophorae, in the city of Maceió (AL), Brazil. The highly infected hosts had half-open leaflets with weak, slow retraction of the adductor muscles. Variable number of ellipsoid oocytes, either isolated and or clustered, was found between myofibrils of the adductor muscle. Each oocyst was incarcerated in a parasitophorous vacuole of host uninucleated phagocyte. The oocysts were composed of a dense wall containing a uninucleate vermiform sporozoite. The wall of the fine oocysts was composed of homogeneous electron-lucent material formed by three layers of equal thickness, having a circular orifice-micropyle obstructed by the operculum. The oocysts presented ellipsoid morphology with their wall was surrounded by a complex network of numerous microfibrils. Important details of the taxonomic value were visualized such as the ultrastructural organization of the oocyst wall and the organization of the micropyle and operculum, beyond the microfibrils that protrude from the oocyst wall only observed by transmission electron microscopy (TEM) and that may aid in the identification of the species. However, in order to clarify the systematic position of the species reported of the genus Nematopsis, it is important to proceed with genetic analyses.

The feeding mechanism of Yoldia ( ═ Aequiyoldia ) eightsi (Courthouy)

1988 ◽  
Vol 232 (1269) ◽  
pp. 431-442 ◽  
Keyword(s):  
Posterior Part ◽  
Dry Mass ◽  
Mantle Cavity ◽  
Bivalve Mollusc ◽  
Suspension Feeder ◽  
Surface Layers ◽  
Processed Material ◽  
Ciliary Action ◽  
Inhalant Siphon ◽  
Mass Basis

The protobranch bivalve mollusc Yoldia eightsi Courthouy is both a deposit feeder (on mud) and a suspension feeder (on diatoms in the ventilatory streams, which are trapped on the ctenidia). The species has a similar anatomy to other Yoldia species, but is a more shallow burrower which adopts a more horizontal shell orientation than the vertically burrowing Yoldia limatula and Yoldia ensifera . Although capable of feeding on the surface layers of mud by extending its palp proboscides outside the partly buried shell, Yoldia eightsi spends most of its time feeding while totally buried. To do this, sediment is taken into the mantle cavity by opening the shell valves, or by foot movements. The sediment is moved by ciliary action to the posterior part of the mantle cavity where it forms a compact, mucus-coated sediment slug. The slug is repeatedly sorted largely by the palp proboscides, fine material being transferred to the mouth via the palps. Sorting appears to be done on a simple size–density basis, with large, dense particles being rejected. After sorting, the inorganic fraction of the slug is expelled through the inhalant siphon (‘pseudofaecal plume’). Expulsions occur every 6–35 min. True faeces (‘faecal plume’) are expelled much more frequently in the expiratory bursts of water from the exhalant siphon. Pseudofaecal output is about 170 times the faecal output (on a dry mass basis), suggesting that Yoldia eightsi ingests 0.6% of processed material.

Cytochemical studies of the neuromuscular systems of the diporpa and juvenile stages of Eudiplozoon nipponicum (Monogenea: Diplozoidae)

Parasitology ◽  
2003 ◽  
Vol 126 (4) ◽  
pp. 349-357 ◽  
Author(s):  
T. H. ZURAWSKI ◽  
A. MOUSLEY ◽  
A. G. MAULE ◽  
M. GELNAR ◽  
D. W. HALTON
Keyword(s):  
Ventral Sucker ◽  
Adductor Muscle ◽  
The Body ◽  
Confocal Scanning Laser Microscopy ◽  
Nervous Systems ◽  
Adductor Muscles ◽  
Neuromuscular Systems ◽  
Juvenile Stages ◽  
Confocal Scanning Laser ◽  
Eudiplozoon Nipponicum

Using indirect immuno- and enzyme-cytochemical techniques, interfaced with confocal scanning laser microscopy and standard optical microscopy, neuronal pathways have been demonstrated in whole-mount preparations of the unpaired diporpae and freshly paired juvenile stages of Eudiplozoon nipponicum (Monogenea: Diplozoidae). All 3 main classes of neuronal mediators, cholinergic, aminergic and peptidergic, were identified throughout both central and peripheral elements of a well-differentiated orthogonal nervous system. Neural mapping revealed considerable overlap and similarity in staining of the nervous systems of the diporpa and adult worm. The main differences in the diporpa relate to the innervation of the temporary ventral sucker and dorsal papilla, structures which are unique to the larva and which enable fusion between worms but then disappear. Branches from the longitudinal nerve cords innervate these structures and appear to be involved in the process of somatic fusion, probably giving rise to the inter-specimen connections that later link the 2 central nervous systems in paired adult parasites. In the hindbody, there is extensive haptoral innervation associated with the developing clamps and small central hooks. Reactive neuronal components were found associated with the early stages of clamp development prior to connections being made with the extrinsic adductor muscle bundles. The muscle systems of the diporpa and juvenile stages comprise a lattice-like arrangement of circular, longitudinal and diagonal fibres that make up the body wall, together with buccal suckers, haptoral clamps and associated adductor muscles, and the transient ventral sucker. All have obvious importance to diporpae when they migrate over the gill and undertake body contact, torsion and fusion during the process of pairing. Behaviour during the pairing of diporpae is described.

Gross Structure of the Adductor Muscles of Some Pelecypods

1973 ◽  
Vol 30 (10) ◽  
pp. 1583-1585 ◽  
Author(s):  
Carol M. Morrison ◽  
Paul H. Odense
Keyword(s):  
Mytilus Edulis ◽  
Crassostrea Virginica ◽  
Adductor Muscle ◽  
Mya Arenaria ◽  
Placopecten Magellanicus ◽  
Spisula Solidissima ◽  
Arctica Islandica ◽  
Modiolus Modiolus ◽  
Adductor Muscles ◽  
Clinocardium Ciliatum

A study of the gross structure of adductor muscles of the following pelecypods showed that they conform to Morton’s grouping into the a) "Protobranchia" (Nucula proxima and Yoldia limatula), b) "shallow-burrowing lamellibranchs" (Clinocardium ciliatum, Venericardia borealis, Astarte undata, Arctica islandica, Venus mercenaria, and Spisula solidissima), c) "surface attached lamellibranchs" (Mytilus edulis, Modiolus modiolus, Modiolus demissus, Placopecten magellanicus, and Crassostrea virginica), d) "deep-burrowing and immobile lamellibranchs" (Ensis directus, Hiatella arctica, and Mya arenaria); thus providing more evidence for his classification. The adductor muscle is divided into two portions — translucent and opaque — except in the "deep-burrowing and immobile lamellibranchs", which have opaque muscles only.

On the Habits and Adaptations of Aloidis (Corbula) Gibba

1946 ◽  
Vol 26 (3) ◽  
pp. 358-376 ◽  
Author(s):  
C. M. Yonge
Keyword(s):  
Great Reduction ◽  
Inorganic Material ◽  
Left Valve ◽  
Byssus Thread ◽  
Adductor Muscles ◽  
Inhalant Siphon ◽  
The Asymmetry ◽  
The Right ◽  
Marginal Region

1. Aloidis (Corbula) gibba is a eulamellibranch specialized for life in muddy gravel substrata to depths of up to about 80 fathoms.2. The shell is asymmetrical, the margin of the smaller, left valve being uncalcified and so fitting within the marginal region of the right valve. A possible manner in which this asymmetry is produced by the differential secretory activities of the two mantle edges is discussed.3. The marginal periostracum of the left valve has strengthening calcined regions posteriorly, probably to protect the siphons when extruded.4. The external ligament is reduced and the resilium condensed, possibly permitting some antero-posterior rocking of the shell valves when the adductors contract.5. The process of burrowing is described; on its completion the animal is anchored by a single byssus thread.6. The siphons are very short, the tentacles of the siphonal sheath lying on the surface of the substratum. The inhalant siphon is wide and relatively insensitive; it draws in much bottom material. The exhalant siphon is tubular and very sensitive. It is controlled by two paired bands of muscle.7. The great quantities of pseudo-faeces which accumulate are expelled by periodical contractions of the 'quick' portions of the adductor muscles, the asymmetry of the shell valves causing great reduction in the size of the inhalant chamber. The foot may also assist in clearing the chamber. 8. The large ctenidia create a very powerful current; they are adapted for dealing with large amounts of sediment by means of specialized terminal, guarding and cirrus-like cilia. Control of 'pumping' is primarily by means of the exhalant siphon.9. The stomach is large in correlation with the great amounts of inorganic material carried in with the food.

scholarly journals Greft İmplantasyonunda İnci Kesesi Oluşumunun Dört Midye Türünde (Unionidae) Karşılaştırılması

2019 ◽  
Vol 7 (10) ◽  
pp. 1699
Author(s):  
Hülya Şereflişan
Keyword(s):  
Survival Rate ◽  
Mantle Cavity ◽  
The Other ◽  
Tissue Slices ◽  
Mantle Tissue ◽  
Pearl Sac ◽  
Different Types ◽  
Pearl Formation ◽  
Graft Implantation

In this study, the most suitable mantle part and host mussel species for pearl sac formation were determined. A total of 400 mussels, consisting of four different types (Unio terminalis, Potamida littoralis, Leguminaia wheatleyi and Anodonta pseudodopsis) were used. The average dorso-ventral lengths of the mussels were respectively; 7.89±0.25; 7.28±0.38; 10.68±0.27 and 11.14±0.34 cm. Mantle tissue slices in the size of 3×3 mm obtained from the pallial edge of mantle tissue were used as grafts. Two different mantle sections were identified for graft implantation, one being the mantle cavity and the other was incisions on the mantle tissue. At the end of the three-month pearl culture, the mantle cavity section was identified as the best graft implant site. U. terminalis was determined as the most successful species in terms of survival rate and pearl formation. P. littoralis was the second successful species and L. wheatleyi was the lowest among the species. This study is a guide for long-term pearl production on nacre thickness and quality which are considered important in pearl production.

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