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At least 1,153 records · Page 64Linked to original sources
PubMed1985

Metabolic adaptations of intertidal invertebrates to environmental hypoxia (a comparison of environmental anoxia to exercise anoxia).

By comparing environmental anaerobiosis with exercise anaerobiosis it appears that animals with high anoxia tolerance use (partly) different types of metabolic reactions to sustain energy metabolism, whereas low tolerance animals (Arthropoda, Echinodermata, Vertebrata) use the same pathway under both conditions. During exercise anaerobiosis the classical glycolysis (lactate pathway) is a main pathway among all multicellular organisms, although in marine invertebrates--except the Arthropoda and Echinodermata--it mostly does not terminate in lactate. During environmental anaerobiosis Cnidaria, Mollusca, Annelida and Sipunculida first couple additional pathways for energy extraction to the glycolytic pathway (the aspartate--succinate pathway) and later deviate the main carbon flow of glycogen at the level of phosphoenolpyruvate towards succinate, propionate and acetate production. Metabolic adaptations to anoxic cellular conditions in these groups are high fuel stores, increased ATP yield by anaerobic sources, formation of easily excretable (volatile) end products, an aspartate-dependent system for transport of hydrogen through the inner membrane of the mitochondrion and a rapid recovery from anaerobic metabolism. During anaerobic conditions three sources can contribute to the anaerobic power output, endogenous stores of both ATP and phosphagen and catabolism. Anaerobic power output rates have been calculated for a number of Mollusca, Annelida and Crustacea. Extreme anoxia resistance is coupled to a strongly reduced metabolic rate. In animals with high aspartate stores, the aspartate--succinate pathway and phosphagen hydrolysis can provide sufficient ATP during environmental anaerobiosis; however, with exercise anaerobiosis when ATP turnover rates may be increased by a factor of 20, pyruvate derivatives simultaneously accumulate in high amounts relative to succinate.

Adaptation, Physiological↗
PubMedDate not supplied

[The life cycl of Maritrema pyrenaica Deblock et Combes, 1965, a parasite of insectivorous micromammals in the Pyrences (author's transl)].

The life cycle of Maritrema pyrenaica is described. M. pyrenaica develops to the sporocyst stage in the snail Bythinella reyniesii. The xiphidio-cercaria, monostomous, anenterous in type, is liberated in water and actively penetrates a Crustacea Gammarus pulex where it encysts. From the point of view of epidemiology, the focuses of M. pyrenaica are divided into two different areas: the area where the parasites multiply (that we call "l'endemiotope") coinciding with the Bythinella biotope and the area limited to the length of the river where the Vertebrate is parasitized.

Animals↗
PubMed1984

[Bioaccumulation of lithium by marine organisms in European, American, and Asian coastal zones: microanalytic study using secondary ion emission].

37 species of aquatic mammals, fish, crustacea, annelids, molluscs belonging to cephalopods, gasteropods and lamellibranchs were collected from coastal waters of France: North Sea, English Channel, Atlantic Ocean, Mediterranean Sea, from Greece: Aegian Sea, from North America: Atlantic Ocean and from Japan: Pacific Ocean, Sea of Japan and East China Sea. Microanalyses which were performed on organs and tissues, using secondary ion mass spectrometry, revealed high concentrations of lithium, which is commonly used in human therapy, but is also toxic in low amounts. The retention of this metal by the marine organisms appears as a general phenomenon independent of their biotope and geographical origin; the highest lithium levels were detected in the fish muscles (= edible part).

Animals↗
PubMedDate not supplied

[Demonstration of life cycle with four obligatory hosts of the Hemiurid Trematodes].

Research on the transmission of Hemiurid Trematode Halipegus ovocaudatus in experimental and natural conditions demonstrates the following: --the miracidium grows into a sporocyst producing rediae in the Mollusc Planorbis planorbis; -- the cystophorous cercariae become mesocercariae in the hemocoele of Copepodes or finally Ostracodes when swallowed; -- the mesocercariae become matacercariae in the mesenteron of larval Odonates (Zygoptera and Anisoptera) when these larvae swallow the Crustacea; -- the metacercariae become become adults in the Amphibial Rana ridibundal perezi which feeds on dragonflies. The four hosts (Mollusc -- Crustacean -- Odonat -- Amphibian) are obligatory in the life cycle for it is impossible to infect the Insects directly with the cecariae or the frog (tadpoles as well as adults) with the mesocercariae. The different stages of the life cycle of H. oveocaudatus aredescribed and the mode of the transmission is compared with the other species of Halipegus and with the Trematodes in general. The adaptative value of the lengthening of the cycle is discussed from the point of view of the conquest of terrestrial hosts by the Hemiurid Trematodes.

Amphibians↗
PubMedDate not supplied

Control of integration by extrinsic inputs in the crustacean pyloric circuit.

The pyloric circuit (14 neurones) in the stomatogastric ganglion of crustacea (Jasus, Homarus) is the central pattern generator of the motor output which governs the rhythmic movements of the pyloric chamber (Fig. 1). Although the intrinsic burstiness of these neurones plays a crucial role in the generation of the rhythmic output, it is demonstrated here that expression of this burstiness is completely dependent on extrinsic inputs (Fig. 2). Tonic firing of an identified interneurons (APM) projecting to the pyloric circuit is able to induce bursting in pyloric neurones. It also modifies the characteristics of the regenerative changes in membrane potential which underly bursting of these neurones (Fig. 3). Tonic firing of APM strongly modifies the phase at which each pyloric neurone fires in the cycle (Fig. 4 and 5). This phage control also appears to be achieved through control of the bursting properties of the pyloric neurones. Rhythmic firing of an identified pyloric oscillator neurone (CP) in the commissural ganglia (Fig. 6) that projects to the circuit in the stomatogastric ganglion, is able to entrain the pyloric rhythm (Fig. 7). Each pyloric neurone can be entrained by CP with different coupling ratios (Fig. 8). This higher order oscillator appears to act as a frequency controller of the bursting of each pyloric neurone.

Animals↗
PubMed1981

[Parasites in sea and fresh water fishes].

A total of 429 individuals of three fish families: Clupeidae, Cyprinidae and Percidae were subjected to parasitological investigation. All fishes were from retail shops were they had been kept frozen. The parasites found belong to the groups Monogenea, Trematoda, Cestoda, Nematoda, Acanthocephala, Hirudinae and Crustacea. Almost all endoparasites were localized in the intestines, the ectoparasites on the gills or on the skin. The fishes investigated were slightly infected, but suitable for consumption. The majority of different species of parasites was found in fishes that shoal, which is quite concordant with "Janiszewska's rule".

Animals↗
PubMedDate not supplied

Shellfish hypersensitivity: clinical and immunological characteristics.

Shellfish is one of the most frequent causes of food allergy. We studied 48 patients (25 male and 23 female) with a mean age of 24.2 +/- 1.8 with shellfish hypersensitivity. A clinical questionnaire was carried out and prick tests were performed using a series of aeroallergens and a battery of extracts of squid, shrimp, lobster, crab, mussel and clam. Prick tests were also performed using raw and boiled extracts from fresh squid, octopus and limpet. Total and specific IgE to these allergens were determined. The most frequent causes of symptoms were shrimp (33 cases) and squid (24 cases). The most frequently found symptoms were Urticaria/angioedema (39 patients), asthma (18 patients) and rhinitis (14 patients). Clinical association was found between Cephalopoedae and Lamelibranquiae (p < 0.05 for clam and p < 0.01 for mussel), but not among both groups and Crustaceans. Association between history and Prick was statistically significant for Crustaceae and Cephalopoedae (p < 0.01) but not for Lamalibranquiae. Association between history and CAP was not found for shellfish. Significant differences among prick-tests with raw and boiled extracts were not found. These results suggest that prick test yields better results than CAP does it, in shellfish hypersensitivity, that clinical association among shellfish hypersensitivity can occurs within the same and different Phylum reflecting common epitopes and that squid, octopus and limpet extracts contain a large amount of heat-stable allergens.

Adolescent↗
PubMed1996

[Zooplankton of the Costa Rica Dome: taxonomy and biogeography].

A list of the species and taxa of some pelagic animals from a tropical upwelling region, based on collections made off the coast of Costa Rica is presented. The list includes a total of 224 species, 53 genera and 11 subspecific forms in Cnidaria, Annelida, Mollusca, Artropoda (Crustacea), Chaetognatha and Pisces.

Animals↗
PubMed1996

Checklist of copepods from Gulf of Nicoya, Coronado Bay and Golfo Dulce, Pacific coast of Costa Rica, with comments on their distribution.

A list of 54 copepod species (Crustacea) in 23 families is presented for the Pacific coast of Costa Rica. Identifications are from zooplankton samples of the Victor Hensen Expedition during December 1993 and February 1994. Samples were taken with a Bongo net (0.60 m net opening, 2.50 m net length) with 200 microns mesh size. Oblique hauls were done from the surface to the ground at a towing speed of aprox. 1 knot. 37 species (68.5%) were found in the Gulf of Nicoya, 36 in Golfo Dulce (66.6%) and 17 (31.4%) species were common to both gulfs, while only twelve species (22.2%) were found in Coronado Bay. Four species (7.4%) were distributed along the coast and were common to the three regions: Paracalanus parvus, Euchaeta sp., Oithona plumifera and O. similis. Eleven species of calanoids found normally in the Costa Rica Dome show the influence of typical oceanic waters principally at the mouth of Gulf of Nicoya. Differences were observed in the composition and presence of the copepod species when the inner and outer (upper and lower) parts of both gulfs were compared. Gulf of Nicoya was dominated in its upper part by typical neritic estuarine species like Acartia lilljenborgii, Paracalanus parvus and, Hemyciclops thalassius as well as species of Pseudodiaptomus. On the other hand a more oceanic composition of copepods was observed in the lower part of the gulf. Both small species, like Oncaea venusta, as well as larger species, such as Pleuromamma robusta, Eucalanus attenuatus, E. elongatus and Rhincalanus nasutus, were typical of these waters. Oithona plumifera and O. similis were found in the lower part too; and both species are typical from oceanic water. Coronado Bay was characterized by the presence of typical oceanic species like Neocalanus gracilis, Euchaeta longicornis, Eucalanus attenuatus and Haloptilus ornatus with more transitional species like Clausocalanus pergens and C. furcatus near the coast. In the Golfo Dulce differences in copepod composition were also observed, but the separation of the species was not so evident. Outer stations were represented by oceanic species like Paracalanus aculeatus, Pleuromamma gracilis, Lucicutia ovalis, Candacia catula, Euchaeta wolfendeni and Oncaea mediterranea, while the inner station, located at the upper part of the Gulf, was more characterized by a mixed copepod group, with both neritic species like Pseudodiaptomus wrigthi, Acartia danae, A. clausi, Canthocalanus pauper as well as oceanic species like Scolicithricella marginata, Saphirina nicromaculata or Oncaea conifera. Two species of Coryceaus, C. flaccus and C. speciosus, were identified in the outer stations of Golfo Dulce, while C. brehmi was found in inner stations of Gulf of Nicoya. The majority of copepods found are typical of the east Pacific. This paper constitutes an additional work about the copepods in the Gulf of Nicoya and the first report of copepod species for Coronado Bay and Golfo Dulce.

Animals↗
PubMed1996

Demersal crustacean assemblages along the Pacific coast of Costa Rica: a quantitative and multivariate assessment based on the Victor Hensen Costa Rica expedition (1993/1994).

During the first cruise leg with the RV Victor Hensen to the Pacific coast of Costa Rica in December 1993 (end of the rainy season) the crustacean fauna found in the demersal collections revealed an unexpected species richness and biomass. The Crustacea collections were analyzed qualitatively and quantitatively during the fourth leg (February 1994, dry season) in the three study areas Golfo Dulce (GD), Bahía Coronado in the Sierpe-Térraba-estuary (ST) and Golfo de Nicoya (GN). Qualitative data were available for comparison from the first leg in december 1993. A total of 24 beamtrawl and ten ottertrawl sample collections were done on an area of 860.000 m2 yielding a total of 119 species with a biomass of 37.8 kg (10275 specimens). Despite the smaller area covered by the beamtrawl, it collected a higher number of species and more biomass than the ottertrawl due to the smaller mesh size (0.8 cm). Judging from the shape of the species -per-area-curves, the crustacean fauna appeared as representatively sampled for the study area. As compared with the GN (biomass 0.36 g +/- 0.26, SR = 97) and the ST (0.41 g +/- 0.27, SR = 59) and according to the results of the log-series-plots constructed from the abundance data, the GD seems to be a depauperated area with significantly lower biomass (0.05 g +/- 0.07) and species richness (45 sp.). No crustaceans were found in the center of the deep basin of the GD put parts of the interior gulf with adjacent mangrove areas seem to be important as nursery area for some commercially important penaeid shrimp species. The ST-estuary revealed the highest mean species number per station in the whole study area, but the GN had the highest total number of species. Biomass seems to be regularly distributed and not depth-depending within the GN, while species abundance varies clearly, confirming previous results. In contrast, abundance and biomass correlated well in the ST. Based on the results of the multivariate analysis, seven station groups of particular species assemblages can be distinguished in the study areas. Despite a high variability between stations in abundance and biomass, the following four areas of characteristic species assemblages can be identified which are also confirmed by an independent study on demersal fishes: (1) the interior part of the GN, characterized by juvenile shrimps (Sicyonia disdorsalis, Trachypenaeus fuscina), several patchily distributed anomurans, brachyurans and other predator species like portunids (especially Portunus asper) and pre-adult stomatopods (Squilla spp.); (2) the exterior part of the GN with high amounts of caridean (Pantomus affins, Plesionika spp.) and penaeid shrimps (Sicyonia picta, Solenocera mutator), the highly abundant Iliacantha hancocki and some specimens of the stomatopod Hemisquilla stylifera and the deep water portunid Portunus iridescens; (3) a transition zone between 60 and 120 m water depth with a heterogeneous faunal composition, located in the ST and east of Isla Tortugas in the GN, and (4) the oxygen-depleted shelf edge area, dominated by the galatheid Pleuroncodes monodon. Mass occurrence of this species takes place off the GD and to a lesser extent off the ST-estuary, associated with high numbers of Solenocera spp. There seems to be a general trend of species groupings along abiotic gradients (depth, temperature, oxygen saturation) interrupted by small-scale variations in habitat type, current regime, food availability and other factors not identified in this study. Neither total abundance and biomass nor biotic summary parameters like diversity, dominance or species richness correlated well with the abiotic factors measured during this survey.

Animals↗
PubMedDate not supplied

Distribution of histamine in the CNS of different spiders.

Immunohistochemistry is used to demonstrate histamine-immunoreactivity in the CNS of spiders. We found histamine-immunoreactivity in the photoreceptors of different spiders. Therefore, we suggest that histamine is a neurotransmitter of photoreceptors in all arthropods, since it is also known to occur in the photoreceptors of the other main arthropod taxa (Merostomata, Crustacea, and Insecta). We also describe a system of only six omnisegmental histamine-immunoreactive neurons within the central nervous system. These histamine-immunoreactive neurons can be divided into two subgroups: a dorsal system with two cells per hemisphere and a ventral system with only one cell per hemisphere. All six cells have extended arborizations in both the motor and the sensory areas of all neuromeres in the suboesophageal ganglionic mass. In contrast to araneomorph spiders, two additional sets of histamine-immunoreactive neurons were detected in mygalomorph spiders. The first set consists of seventeen cells with their cell bodies located in the cheliceral ganglion and projecting to central areas of the protocerebrum. The second set contains many if not all sensory projections from the tarsal organs on all eight legs and the pedipalps to the Blumenthal neuropil.

Animals↗
PubMed1996

Larval storage protein of the barnacle, Balanus amphitrite: biochemical and immunological similarities to vitellin.

Biochemical and immunological characterization of cyprid major protein (CMP), the principal protein constituent of cypris larvae of the barnacle Balanus amphitrite (Crustacea: Cirripedia), revealed similarities to egg-yolk protein, vitellin, as follows: CMP and vitellin heavy chain both have a molecular weight of 170 kDa by polyacrylamide gel electrophoresis containing sodium dodecylsulfate; CMP was crossreactive with antiserum against vitellin heavy chain in immunoblot analysis. The sequence of 11 amino acids in the amino-terminus of CMP, however, is not perfectly homologous to that of vitellin heavy chain. Thus, it was deduced that CMP was an isoform of vitellin. Concentration of CMP abruptly increased during the latter naupliar stages, reaching a peak just after metamorphosis to the non-feeding cypris stage, and decreased thereafter with aging of cyprids or during the early juvenile period. Specifically, the concentration of CMP in newly metamorphosed juveniles within one day decreased to 20% that of cyprids. CMP, therefore, appears to function as a storage protein during settlement of cyprids as well as metamorphosis to juveniles. Immunohistochemical analysis using antiserum against vitellin heavy chain on sectioned cyprids suggested that CMP is accumulated in the haemocoel.

Animals↗
PubMed2000

Determination of amino acid sequence and site of mRNA expression of four vitellins in the giant freshwater prawn, Macrobrachium rosenbergii.

Four major yolk proteins, designated as vitellins (Vns) Macr-VnA, B, C, and D, were extracted from mature ovaries of Macrobrachium rosenbergii. These were purified to homogeneity by reversed-phase high performance liquid chromatography (HPLC) employing a unique separation system based on the hydrophobic properties of the Vn molecule. Using standard techniques of protein sequencing, more than 33 N-terminal and 57 internal amino acid residues were determined for each of the four Vns. The cDNA fragments encoding the four Vns were amplified by PCR using degenerate oligonucleotide primers derived from the N-terminal and internal amino acid sequences. These cDNA fragments were cloned, sequenced, and used as probes to examine the transcription of mRNAs encoding the four Vns. Significant accumulations of these mRNAs were observed in female hepatopancreas only, while mRNA expression was not detected in male hepatopancreas or any other female tissue including ovary, subepidermal adipose tissue, gill, and muscle. This is the first occasion in Crustacea in which multiple Vns were demonstrated to be synthesized simultaneously in a single tissue.

Amino Acid Sequence↗
PubMed1993

An ethologist aboard HMS Beagle: the young Darwin's observations on animal behavior.

Darwin's notes from the Beagle period abound with observations on animal behavior. Although in places anecdotal and anthropomorphic, they include many detailed, lively comments of the activities of birds, reptiles, mammals, crustacea, insects, and other invertebrates. In his comparative approach, belief in the importance of heredity, an understanding that behavior might be of assistance in taxonomy, and that it was linked with both the organism's morphology and habitat, and his attempts at experiments, Charles Darwin in his early and mid-twenties was using techniques and concepts that were to be of great significance in his later work.

Anatomy, Comparative↗
PubMed2005

Organization of optic lobes that support motion detection in a semiterrestrial crab.

There is a mismatch between the documentation of the visually guided behaviors and visual physiology of decapods (Malacostraca, Crustacea) and knowledge about the neural architecture of their visual systems. The present study provides a description of the neuroanatomical features of the four visual neuropils of the grapsid crab Chasmagnathus granulatus, which is currently used as a model for investigating the neurobiology of learning and memory. Visual memory in Chasmagnathus is thought to be driven from within deep retinotopic neuropil by large-field motion-sensitive neurons. Here we describe the neural architecture characterizing the Chasmagnathus lobula, in which such neurons are found. It is shown that, unlike the equivalent region of insects, the malacostracan lobula is densely packed with columns, the spacing of which is the same as that of retinotopic units of the lamina. The lobula comprises many levels of strata and columnar afferents that supply systems of tangential neurons. Two of these, which are known to respond to movement across the retina, have orthogonally arranged dendritic fields deep in the lobula. They also show evidence of dye coupling. We discuss the significance of commonalties across taxa with respect to the organization of the lamina and medulla and contrasts these with possible taxon-specific arrangements of deeper neuropils that support systems of matched filters.

Animals↗
PubMed2007

Adult neurogenesis: a common strategy across diverse species.

Adult neurogenesis, the generation of new neurons from adult precursor cells, occurs in the brains of a phylogenetically diverse array of animals. In the higher (amniotic) vertebrates, these precursor cells are glial cells that reside within specialized regions, known as neurogenic niches, the elements of which both support and regulate neurogenesis. The in vivo identity and location of the precursor cells responsible for adult neurogenesis in nonvertebrate taxa, however, remain largely unknown. Among the invertebrates, adult neurogenesis has been particularly well characterized in freshwater crayfish (Arthropoda, Crustacea), although the identity of the precursor cells sustaining continuous neuronal proliferation in these animals has yet to be established. Here we provide evidence suggesting that, as in the higher vertebrates, the precursor cells maintaining adult neurogenesis in the crayfish Procambarus clarkii are glial cells. These precursor cells reside within a specialized region, or niche, on the ventral surface of the brain, and their progeny migrate from this niche along glial fibers and then proliferate to form new neurons in the central olfactory pathway. The niche in which these precursor cells reside has many features in common with the neurogenic niches of higher vertebrates. These commonalities include: glial cells functioning as both precursor and support cells, directed migration, close association with the brain vasculature, and specialized basal laminae. The cellular machinery maintaining adult neurogenesis appears, therefore, to be shared by widely disparate taxa. These extensive structural and functional parallels suggest a common strategy for the generation of new neurons in adult brains.

Animals↗
PubMed1987

Segmental origins of the cricket giant interneuron system.

The segmental origins of the cricket giant interneuron system have been studied by staining these neurons with cobalt during the last half of embryonic development. The results demonstrate that the interneurons are derived from three distinct clusters of embryonic neurons that form a serially repeating pattern in each abdominal ganglion. Some of the neurons previously described in adults (Mendenhall and Murphey, '74; Murphey, '85) have been identified in embryos and are described here with respect to this pattern. These neurons include both giant interneurons and several non-giant mechanosensory interneurons that mediate several different sensory modalities. The anatomical organization of this system is compared to similar mechanosensory systems in other insects and crustacea.

Abdomen↗