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At least 19 recordsLinked to original sources
PubMed1991

Biochemical and histochemical observations on effects of low-level heavy metal load (lead, cadmium) in different organ systems of the freshwater crayfish, Astacus astacus L. (Crustacea: Decapoda).

The effects of low-level lead (20 micrograms/liter) and/or cadmium (2 micrograms/liter) exposure on the structure and function of different organ systems of the freshwater crayfish. Astacus astacus L. (Crustacea: Decapoda) were estimated by several biochemical and histochemical methods. The animals were incubated during 10 weeks (max.) at a temperature of 10 degrees C and a normal diurnal rhythm. Lead accumulated in high amounts especially in the digestive gland, carapax, and gills, whereas the hindgut and musculature exhibited very low lead levels. Cadmium accumulated particularly in the digestive gland and gills. Lead and cadmium levels were definitely lower in the digestive gland, gills, and carapax of animals incubated in water containing a double, i.e., lead and cadmium load, than in animals kept in water containing only one of these heavy metals. Histochemically both metals could be visualized in a typical distribution within the tissues, such as the carapax, digestive gland, or gills. After several weeks of poisoning, all organs, but especially the digestive gland, showed severe structural impairment. The activities of oxidative enzymes in the digestive gland and gills were significantly lowered after 2 weeks of incubation. Enzyme histochemical evaluation demonstrated changes of reaction intensities within the organs as compared to the controls. GSH S-transferase activities and GSH contents were also distinctly decreased following lead and/or cadmium intoxification. The histochemical demonstration of SH and S-S groups exhibited a stronger staining reaction after 10 weeks of exposure, especially in digestive gland and gills. The results obtained are discussed in view of the specific impairment of function of the organ systems studied, as related to the typical biology of the animal species tested.

Animals↗
PubMed1983

[Immunochemical study of the proteins of various tissues in Crustacea (Decapoda): nature, role, origin].

The main proteins of the haemolymph of Crustacea Decapoda have been identified and analysed: haemocyanin, plasma coagulogen, heteroagglutinins, vitellogenins, and molt-related proteins. All these complex components exhibit a high molecular weight and as oligomeric fractions are able to aggregate or dissociate in subunits according to the composition of medium and experimental procedures. Besides their important rôle in the defense mechanism, some proteins are involved in the edification of diverse tissues. They are detected within different compartments: soft integument, calcified carapace and hepatopancreas. They are either in transit or sequestered or synthetized within these tissues. In the crayfish Astacus leptodactylus, some components have been identified in different compartments: --in aqueous extracts from soft integument: the haemocyanin, coagulogen and both fraction F1 (lipoprotein with an approximate molecular weight of 45 kdal) and fraction F2 related to the molt. Both coagulogen and fraction F2 appear sometimes as melanized. These two latter fractions exhibit some glucose-mannose residues and they occur with a higher relative amount than in the blood. --in soluble extracts from calcified cuticle: among the numerous fractions showing a high molecular weight, the haemocyanin and coagulogen are detected. --in aqueous extracts from hepatopancreas: both haemocyanin and coagulogen appear with a little relative amount. Components termed as Fa and Fb are found with a high concentration. One minor fraction is also detected. --in aqueous extracts from eggs: the haemocyanin and fraction Fb are present. Other proteins showing only some antigenic identities with those of the haemolymph are also detected in all these tissues. The haemolymph proteins are not present within these compartments following a passive diffusion. Indeed, their relative amount varies according to the tissue investigated and is different from that found in the blood. Except the haemocyanin detected in all tissues with different aggregation states, the haemolymph proteins identified vary in the organs studied. A qualitative and quantitative selection occurs when the blood proteins enter the other compartments. Perhaps some other proteins are not detected following alterations underwent either in the epithelial barriers or during the tannage process or the chitino-proteic complex formation or due to experimental procedures. On the other hand, each tissue has its own proteins. The integument contains crustacyanins alpha, beta, gamma; the eggs are mainly constituted of lipovitellins and the hepatopancreas is rich in small molecular weight proteins and digestive enzymes.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1977

[Unilateral change in color produced by ablation of the eyestalk of the crustacean Processa edulis (Decapoda, Natantia)].

A difference of expansion of erythrophores is observed between the left and right side of P. edulis after the removal of only one Eyestalk. It is the first time, in the Crustacea, that experiments lead to the conclusion that a sympathetic-like constrictor nervous action can exist in colour-change control; colour changes are particularly fast in this species.

Animals↗
PubMed1988

Localization of serotonin-like immunoreactivity in the eyestalk of the prawn Palaemon serratus (Crustacea, Decapoda, Natantia).

A serotonin-like substance in the organ of Bellonci in the eyestalks of embryos, larvae, and adults of the prawn Palaemon serratus was visualized by the use of two specific antisera against serotonin (5-hydroxytryptamine; 5-HT) in combination with peroxidase-antiperoxidase (PAP). The organ of Bellonci, characterized by compact onion bodies distally and degenerating onion bodies proximally, was the only site of the serotonin-like substance in adults, as well as during development in embryos and larvae. Variations in the content of the 5-HT analogue in the adult were detected during the molting cycle. There was more immunoreactivity in specimens fixed at night than in those fixed in daytime. Likewise, colchicine and nialamide injections enhanced the immunoreactivity of the serotonin-like substance. Extirpations of the medulla externa X organ (MEX), a neurosecretory cell group of the optic ganglion medulla externa, produced the same effect.

Animals↗
PubMed1976

On the fine structure of the regressing ecdysial glands of carcinus maenas L. (Crustacea Decapoda) parasitized by Sacculina carcini Thompson.

The ecdysial glands (Y organs) of the crab Carcinus maenas regress in the presence of an external parasite, Sacculina carcini. This regression is more or less severe and may lead to complete autolysis. Three gradual stages in this involutionary process are described. In stage I, the gland cells are nearly normal. Nuclei and cytoplasmic organelles remain unchanged, but large vacuoles begin to appear. Stage II corresponds to more or less drastic nuclear pyknosis and cytoplasmic alterations. Myelin figures are large and numerous. Lysosomes and autophagic vacuoles with phosphatase activity are abundant. However, the general cellular architecture remains preserved. Stage III corresponds to irreversible cytolysis; nuclear envelopes and plasma membranes have disappeared. What remains is an accumulation of cellular debris becoming engulfed by circulating hemocytes. Not all of the gland cells of any given Y organ show the same degree of regression; degeneration is asynchronous. Structures seemingly corresponding to absorptive roots of the parasite are seen. Their lumen is coated with microvilli. The putative direct and indirect influences of the rhizocephalan parasite on its host are discussed. Our results on regressing Y organs of parasitized crabs are compared with those on regressing ecdysial glands of insects.

Animals↗
PubMed1975

The membrane systems of the cardiac muscle cell of Munida tenuimana G. O. Sars (Crustacea, Decapoda).

The membrane systems of the cardiac muscle cell of Munida tenuimana G. O. Sars are described. The sarcolemma invaginates at the Z level, forming tubules. Narrow tubules branch off in a longitudinal direction from these transverse and radially arranged tubules, forming a narrow transverse collar at the H level where dyadic and triadic junctions are formed with the sarcoplasmic reticulum.

Actins↗
PubMed1975

The microanatomy of the compound eye of Munida irrasa (Decapoda: Galatheidae).

The compound eye of Munida irrasa differs in several respects from the typical decapod eye. The proximal pigment is found only in retinula cells. The eccentric cell is extremely large and expanded to fill the interstices of the crystalline tract area; thus, a typical "clear-zone" is absent. Six retinula cells course distally to screen two sides of the crystalline cone. There are approximately 12,500 ommatidia in each compound eye. There are several similarities to the typical decapod eye. Each ommatidium is composed of a typical cornea, corneagenous cells, crystalline cone cells, crystalline cone, crystalline cone tract and eight retinula cells. Distal pigment cells are present and surround the crystalline cone. The distal processes of the retinula cells also contain pigment. The retinula cell processes penetrate the basement membrane as fascicles composed of processes from adjacent retinulae.

Animals↗
PubMed1984

Are the funnel-canal organs the 'campaniform sensilla' of the shore crab, Carcinus maenas (Decapoda, Crustacea)? II. Ultrastructure.

The funnel-canal organs on the dactyls of the shore crab, Carcinus maenas, are innervated by 3-24 sensory cells with unbranched dendrites, which attain a length of 500-1400 micron. The outer dendritic segments are enclosed in a dendritic sheath and pass through the cuticle within a canal. Two dendrite types can be distinguished according to ultrastructural criteria: Type I has a long ciliary segment, A-tubules with an osmiophilic core and arms, and a thick ciliary rootlet. Type II possesses only a short ciliary segment and a thin ciliary rootlet. Each funnel-canal organ contains two type-I dendrites. Their ciliary bases appear a few micron distal to those of the type-II dendrites (1 to 22 in number). Two inner and two to eight outer enveloping cells belong to a sensillum. The innermost enveloping cell contains a large scolopale. In the second enveloping cell single scolopale rods are present. Thus, the funnel-canal organs are characterized by structural features typical for mechanosensitive scolopidia, on the one hand, and for chemoreceptors, on the other. Therefore, the funnel-canal organs are very likely bimodal sensilla (contact chemoreceptors). A comparison with other arthropod sensilla shows that cuticular mechanoreceptors of aquatic crustaceans generally exhibit a 'scolopidial' organization.

Animals↗