Spelling suggestions: "subject:"crustacea"" "subject:"crustacean""
51 |
Responses of benthic macrofauna to the dynamics of a Gulf Stream front on the continental shelf near Cape Hatteras, North CarolinaHarrington, Cynthia Lucile, January 1981 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1981. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
|
52 |
Studies on the postembryonic development of Hyalella azteca (Saussure)Geisler, Grace, January 1944 (has links)
Thesis (Ph. D.)--Catholic University of America, 1944.
|
53 |
Gelation of Previously Cooked Jonah Crab (Cancer borealis) Minced Meat in New Food Product DevelopmentBaxter, Shari R. January 2007 (has links) (PDF)
No description available.
|
54 |
Two newly described sensory systems in decapod crustacea : 1. The campaniform organ system; 2. The chemoreceptor hair systemShelton, Richard Graham John January 1968 (has links)
(1) Evidence is presented that the ''Funnel Canal Organs" described by Luther (1930) are not contact chemoreceptors. (2) Experiments are described which indicate that the Funnel Canal Organ is a mechanoreceptor which responds to strain applied to the cuticle. (3) Histological observations suggest that these sense organs are actually campaniform sensilla which occur both singly and in groups, to form compound sense organs. (4) The relationship between campaniform and chordotonal organs is discussed. (5) Further experiments show that a large variety of chemoreceptor hairs exits. Most are branched and there is a negative correlation between the surface area of the hair (degree of branching) and the amount of irrigation to which the hair is normally subject. (6) The view is expressed that the concert of contact chemoreception is of limited use when considering aquatic Crustacea. The Hair Plate Organs of the chelate pereiopods are suggested as the only chemoreceptor organs in aquatic Decapoda which fulfil a true contact role.
|
55 |
The optokinetic responses of the crab, Carcinus maenasBarnes, William Jonathan Peter January 1967 (has links)
The movements of the eyecups of the common shore crab, Carcinus maenas L., that occur in response to a variety of different visual stimuli, have been studied with a view to analysing the mechanisms of eye movement control in the crustaces. In most experiments, a light flag was glued to one of the crab's eyecups. The flag was orientated so that is partially occluded a beam of light that was focused on a pair of photocells, mounted in opposition to one another. Flag movements thus caused changes in the amount of light reaching the photocells, whose outputs were amplified and displayed on a pen recorder. That small eyecup movements occur in the absence of moving stimuli has been confirmed. These movements have been classified into four categories; tremor - oscillations of peak to peak amplitude 0.01° - 0.2° and predominant frequency 1-3 o.p.s., which could be modified to a small extent by external stimuli; drift - slow wondering movements that mainly occurred when there were no contracts in the visual field; saccades - spontaneous jumps whose frequency and amplitude were extremely variable; and scanning movements of amplitude 0.1° -2.0° peak to peak, and frequency 2-3 o.p.s.; which were always associated with periods of leg waving. All other experiments were directly concerned with the optokinetic responses of Carcinus, which were usually elicited by rotating a black and white striped drum around the crab. Optokinetic nystagnus consists of two phases, a slow forward phase during which the eyes move in the direction of rotation of the stripes, and a fast return phase in which the eyes are flicked back in the opposite direction. Although the evidence is by no means conclusive, it appeared that carcinus has neither a proprioceptive nor a coulometer feedback loop in its eye movement control system. It may thus be unable to distinguish apparent motion, induced by its own eye movement, from world motion. Optokinetic responses also occurred to the movements of a pinlight in an otherwise dark visual field. When recorded in two dimensions on an X-Y plotter, the responses to the movement of a pinlight in a circle were seen to be approximate ellipses, though stepwise movements frequently occurred instead of diagonal movements. The possibility, suggested by this observation, that carcinus resolved diagonal movements into their horizontal and vertical components was confirmed by the finding that the angles of the responses to diagonal movements of the pinlight depended upon the ration of the gains (gain equals response divided by stimulus) to horizontal and vertical pinlight movements. The possibility that carcinus uses this ability to resolve the sun or moon's motion cannot be excluded. When one pinlight was switched off and a similar one was switched on nearby, the crab responded optokinetically, the amplitude of this response being proportional to the stimulus amplitude for apparent movements of up to 3° -4 °. This suggests that movement correlation takes place primarily between closely spaced ommatidia. The responses to the movement or apparent movement of two or more lights were proportional to the shift in the centre of light intensity, an indication that the spatial resolution of the eyes is poor. Optokinetic memory responses, which occur following shifts in the drum position that are not seen by the crab, were also studied. By varying the length of time that the crab viewed the stripes before they were moved, memory was shown to build-up approximately linearly, reaching a plateau representing a gain of between 6 and 30 after 40-100 seconds. The retention of memories allowed to build-up for different periods of time was also examined. There was no evidence for the existence of more than one memory store.
|
56 |
Development of gene probes to P virus (Reoviridae) for disease diagnosis in crustaceansWalton, Alison January 1999 (has links)
This study reports the development of two important techniques, gene probes and haemocyte cultures that have not been previously available to investigate viral diseases in temperate water marine decapods. These techniques were used to investigate numerous aspects of a reovirus infection of the swimming crab Liocarcinus depurator, P virus, both in vivo and in vitro. The construction and subsequent use of a gene probe has revealed that, not only can virus be experimentally transmitted to L. depurator by injection, but that it is present in natural populations of crabs from the North Sea. Seasonal variation in both incidence of P infection and in incubation time was observed. The incidence of infection increased with increasing temperature whereas incubation time decreased with increasing temperature. In vivo, P virus was found to cause marked haemocytopenia in infected L. depurator and a cytopathic effect, vacuolisation of haemocytes was observed. This effect was not observed in the haemocytes of the shore crab, Carcinus maenas, providing evidence that P virus does not infect this species. To address the lack of techniques for in vitro studies, a cell culture system for crustacean haemocytes was developed. Primary culture of two haemocyte types, hyaline and semi-granular haemocytes was established for haemocytes of both L. depurator and C. maenas. High haemocyte viability was obtained for at least two weeks and, cells retained their functional capabilities in vitro. Having successfully established a haemocyte culture system and the gene probe E2b, it was then possible to begin investigations on P virus infections in vitro. P virus produced a number of effects on haemocytes of L. depurator in vitro. Haemocyte number and haemocyte viability decreased after addition of P virus and a number of cytopathic effects were observed such as necrosis, pycnosis and vacuolisation.
|
57 |
Antibacterial activity in the blood cells of Carcinus maenas (L.) and other crustaceansChisholm, June R. S. January 1993 (has links)
In vitro antibacterial activity in the haemocytes of Carcinus maenas (L) was investigated. Haemocyte lysate supernatants (HLS) were assayed against twelve Gram-positive and Gram-negative marine bacteria, eight of which proved sensitive to the antibacterial factor or factors contained therein. Antibacterial activity was also found in HLS from four other marine crustaceans-Glyptonotus antarcticus, Galathea strigosa, Nephrops norvegicus and Crangon crangon. Activity in C. maenas HLS was independent of divalent cations, operated at high titre, was stable after treatment at 100 °C for 30 minutes and also after three months storage at -70 °C; it was present in the granular cells (which also contain the prophenoloxidase (proPO) activating system, a putative recognition mechanism in arthropods), but was absent from hyaline cells and plasma. In vitro studies were carried out to determine whether a relationship exists between the proPO system and the antibacterial activity in the haemocytes of C. maenas. It was shown that phenoloxidase and an activating serine protease were not responsible for the observed antimicrobial effects, although the possibility that activity resides with some other component of the proPO system has not been excluded. Seasonal variation in antibacterial activity, haemocyte counts and HLS protein concentrations was found, with conspicuous depression of antibacterial activity at two key points in the year. This occurred in conjunction with extremes of water temperature and it is proposed that the variation in antibacterial activity is due to underlying temperature effects on haemocyte counts and protein levels. Low levels of lytic activity against Micrococcus luteus cell walls and low levels of bacterial agglutination were recorded, but the powerful antibacterial activity in HLS could not be attributed to these alone. Gel filtration with Sephadex G-l00 revealed at least three antibacterial proteins of differing molecular size, with estimated MW of 72 kDa, 34 kDa and 4 kDa. The 72 kDa and 34 kDa proteins were bacteriostatic and the 4 kDa protein was bacteriolytic.
|
58 |
The dorsal organ and other cuticular structures in larval and adult Crustacea : an ultrastructural studyBarrientos Chacon, Yolanda January 1985 (has links)
SEM observations on the integument of larvae and adult Crustacea Malacostraca indicated differences in setal armature, and in types and frequency of occurrences, which seem to be related with development and sensilla body position. The Amphipoda and Isopoda species studied share a common type of articulated conical spine on the pereiopod segments. In each species, the conical spine has a modified apex which contains sub-apical setules whose tips are provided with ventrally positioned pores or bifid ends. The epimeral and lateral body plates are covered by short articulated pegs with modified hair bases: asymmetrical lip-like extensions, knobs or vesicle-like projections around the hair rim. An unusual type of aesthetasc sensillum is present on the male Cumacea antennal flagellum. A sub-terminal and ventrally positioned pore is present in these aesthetascs whose tips are divided. Companion and guard hair sensilla are absent. A number of cuticular out/ingrown structures are described in both Decapoda and non-Decapoda Crustacea which cannot be related with any previous classification schemes. Crustacea Decapoda larvae (Macrura, Anomura, and Brachyura) have a common trichoid sensillum, whose numbers and distributional patterns are specific for each group. There is a tendency for the trichoid sensilla to be arranged in clusters rather than describing ramdon patterns. Setal organization changes according to developmental instars: larva and post-larval forms have small numbers and types of sensilla, or in some cases they possess the incipient forms of receptors such as the funnel-canal organs known to be present in the pereiopods of adult animals. Juvenile stages exhibit a more complex and sophisticated setal arrangement. Brachyura stage IX-X embryos and hatchling larvae are equipped with well anatomically organized (TEM) sensory hairs. According to their ultrastructural features potential mechano-, and chemoreceptive hairs can be differentiated in the antennules and maxillipeds. In the dorsal median anterior region of the head, Decapoda larvae possess a discrete organ: glandular-sensory complex. Its external topography reveals the presence of one or two central pores (Brachyura, Anomura) or a poreless central area (Macrura) surrounded by four equidistant plate-pits which contain a central pimple or cone. The Macrura plate-pits lack the central cone but develop a row of diminutive pegs. The dorsal organ ultrastructure reveals several components: a gland cell, a ductule cell, two supporting cells and eight sensory cells. The gland cell components allow it to be categorized it as an excretory class 3 gland cell; and the presence of two biciliary sensory cells per plate pit, without scolopale matrix and thick dendritic sheath may identify them as potential chemoreceptors or as bimodal sensitive units. SEM observations indicated that the organ is not present in the integument when juvenile stages are reached. The organ might degenerate or internalize. No definitive function can yet be ascribed to the organ.
|
59 |
A comparative study of proprioception in the appendages of decapod crustaceansWales, William January 1971 (has links)
The number and structure of the chordotonal organs present at all joints between the coxopodite and dactylopodite of the pereiopods and 3rd maxilliped of the Macruran gammarus L are described. As the form of the receptors depends to some degree upon the structure of the joint I have included details of musculature, planes of movement and degrees of freedom at each joint. 2 The 3rd maxilliped has a smaller number of chordotonal organs than the pereiopod, in particular at the merocarpopodite and cargo-propodite joints where only one organ is present. The response of these receptors shows considerable differences from the corresponding receptors in the pereiopoth 3. The structure of the carpo-propodite joint of both limbs is discussed in detail as this joint differs greatly from that of the Brachyura as a third muscle is present. In the pereiopod this joint is capable of rotation about the longitudinal axis but the additional muscle does not appear to produce this rotation. A small number of units in the CP2 receptor respond to rotation. 4. Cuticular sensilla (CAP organs) are described at the mero-carpopodite and carpo-propodite joints in both limbs and at the I-N joint of the pereiopod. 5. Situated in the basi-isehiopodite of the brachyuran Carcinus maenas are two receptors which resemble the chordotonal receptors of the limb articulations but are obviously not part of the series associated with the joints. The receptors have large numbers of bipolar neurones with their dendrites embedded in distinct connective tissue strands which insert onto discrete areas of thin or soft cuticle. The receptor strands do not span a limb joint nor do they attach to a muscle or its tendon. The receptors are referred to as cuticular stress detectors (CSD). CSD.1 lies proximal to the preformed breakage plane and the area of cuticle, onto which the strand inserts, lies close to the attachment of the anterior levator muscle tendon (autotomiser muscle). CSD.2 which lies distal to the breakage plane is located in the ventral ischiopodite. 6. Because of the proximity of the receptors to the preformed breakage plane the external cuticular features of the basi-ischiopodite and the musculature of the coxo-basipodite joint are described in some detail. 7. Comparative details are given for representative species of the Macrura and Anomurn. The nephropsideans, Macrura, are particularly interesting as only the 1st pereiopod, chela, exhibits true autotomy but both receptors are present in all the pereiopods. 8. A third group of bipolar neurones is described in Palinurus vulgaris where they innervate the membrane that seals the aperture after breakage. 9. The dual role of the two levator muscles in both posture control and autotomy and possible functions of the CSDs are discussed at length. 10. The CSD organs respond to pressure applied to the basi-ischiopodite and upon deformation of the discrete areas of soft cuticle onto which the connective tissue strands of the receptors insert. The CSDs exhibit a wide range of unit activity and both receptors have a similar population of unit types. Some units are active only on application or removal of a force applied to the soft cuticle but a large number of phaso-tonic and tonic units respond to a constant pressure applied to the soft cuticle. The majority of the units respond during application of the stimulus (ON units) but a small proportion of the units increase activity on removal, of the stimulus (OFF units). 11. Passively produced tension in the anterior levator (autotomiser) muscle and depressor muscle tendons of the C-B joint is a potent stimulus to both receptors. 12. Both receptors respond to movement of the B-I joint of the Nephropsidean walking leg and to movement of the I-M joint in the pereiopods of other reptantian decapods where the basipodite and ischiopodite have fused. The degree of activity is not directly related -to the joint position or direction of movement.
|
60 |
Taxonomia e biogeografia da família Goneplacidae Macleay, 1838 (Crustacea : Decapoda : Brachyura) no litoral brasileiro /Vezzani, Renata de Macedo. January 2007 (has links)
Orientador: Gustavo A.S. de Melo / Banca: Nilton José Hebling / Banca: Oswaldo Campos Junior / Resumo: A família Goneplacidae com representantes em todos os oceanos tropicais e temperado-quentes inclui 7 gêneros e 13 espécies na costa brasileira. Embora, muito tenha sido escrito sobre os aspectos ecológicos e fisiológicos, a taxonomia do grupo ainda possui problemas a serem resolvidos, porque a bibliografia sobre os Goneplacidae brasileiros está restrita a levantamentos faunísticos, tratamentos sistemáticos de poucos gêneros importantes e indicações de novas ocorrências na costa brasileira. Sobre biogeografia, não há quase nada referente às espécies brasileiras. De fato, os Goneplacidae nunca receberam, no Brasil, nenhuma revisão taxonômica do ponto de vista global. Considerando estes fatos, a revisão deste grupo foi feita usando as coleções carcinológicas do Museu de Zoologia da Universidade de São Paulo e de outros museus brasileiros. Dois padrões longitudinais de distribuição e três padrões latitudinais foram verificados nos Goneplacidae brasieliros. / Abstract:The family Goneplacidae with representatives in all the tropical and warm temperate oceans includes 7 genera and 13 species on the Brazilian coast. Although much has been written about ecological and physiological aspects, the taxonomy of the group left problems to be solved, because present bibliography on Brazilian Goneplacidae is restricted to a few faunistic surveys, in a few areas, systematic treatments of a few important genera and reports of a new occurrences on the Brazilian coast. As for biogeography there is almost nothing about Brazilian species. In fact, the Goneplacidae had never received, in Brazil, any taxonomic revision, at least not from a global view point. Considering these facts, a revision of this group was made using the carcinological collections of the Museu de Zoologia da Universidade de São Paulo and other Brazilian museums. Two patterns of longitudinal distribution and three patterns of latitudinal distribution were verified among the Brazilian Goneplacidae. / Mestre
|
Page generated in 0.0271 seconds