Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Invertebrates”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,045 records · Page 58Linked to original sources
PubMed2004

Insights into the anti-microbial defense of marine invertebrates: the penaeid shrimps and the oyster Crassostrea gigas.

Research on innate immunity of the penaeid shrimps and the oyster Crassostrea gigas is motivated greatly by economical necessities. Indeed, the aquaculture of these organisms is now limited by the development of infectious diseases. Studying anti-microbial peptides/proteins (AMPs), which are effector molecules of the host defense, is particularly attractive not only for progressing basic knowledge on immunity but also because they offer various possible applications for disease management in aquaculture. AMPs are explored with a global approach,considering their structure, properties, function, gene expression, and tissue distribution during the response to infections. In shrimp, investigations of the penaeidins, which are constitutively expressed peptides, have highlighted the importance of hemocytes and hematopoiesis as major elements of the immune response, providing both local and systemic reactions. The activation of hematopoiesis must be regarded as a regulatory way for the expression and distribution of constitutively expressed immune effectors. As complementary approaches, genomics and gene profiling are promising to deepen our understanding of the anti-microbial defense of the oyster and the shrimp. However, real progress will depend also on the characterization of hemocyte lineages and hematopoiesis of these marine invertebrates as well as on the ontogenesis of their immune systems.

Animals↗
PubMed1980

A method for the demonstration of pores in calcified eggs of vertebrates and invertebrates.

Determination of pore number, pore size as well as pore canal distribution is important in understanding the biology of calcified eggs among vertebrates as well as invertebrates. Various techniques have been applied to elucidate pore structure of avian egg shells, including fracturing coupled with scanning electron microscopy and differential histochemical staining of the matrix. The best results reported have thus far been from plastic impregnated, etched specimens (Board & Tullett, 1974). The present report is a modification of this latter technique, utilizing the very low viscosity, highly penetrating electron microscopic embedding medium developed by Spurr (1969). This modification is used in this report of the previously undescribed pores from the egg shells of the giant South American land snail, Strophocheilus oblongus. These eggs, which can be up to 50 mm in length, have recently been investigated with respect to the calcium carbonate mineralogy (Tompa, 1976) as well as with respect to the matrix biochemistry Tompa et al., 1977). (Similar resin has been used successfully for the plastic impregnation and ultrathin sectioning of that region of the snail shell where the body muscles insert into the shell comumella (Tompa & Watabe, 1976).) This technique, which can be utilized on avian eggs or on any other calcified material in probing for pores, relies on the high penetrating ability of the resin as well as on its easy commercial availability around the world.

Animals↗
PubMed2004

Infiltration by alien predators into invertebrate food webs in Hawaii: a molecular approach.

Abstract Alien invertebrate predators have been introduced to Hawaii to control pests, particularly in lowland areas where most crops are grown. We developed techniques for assessing the impact of these predators on native food webs in relatively pristine upland areas where, it was hypothesized, few lowland predators might be found. Predator densities were assessed along transects within the Alakaii Swamp on Kaua'i. The most numerous alien biocontrol agents found were Halmus chalybeus (Coccinellidae), a species known to feed on Lepidoptera eggs. Laboratory experiments were conducted using two genera of endemic Lepidoptera, Scotorythra and Eupithecia (Geometridae), that are of considerable conservation value, the former because of its recent speciation across Hawaii, the latter for its unique predatory larvae. Techniques were developed for detecting Lepidoptera DNA within the guts of alien predators using prey-specific PCR primers. General primers amplified fragments of the mitochondrial cytochrome oxidase I gene from beetles and Lepidoptera. The sequences were aligned and used successfully to design target-specific primers for general detection of the remains of Geometridae and for particular species, including Scotorythra rara and Eupithecia monticolans. DNA fragments amplified were short [140-170 base pairs (bp)], optimizing detection periods following prey ingestion. Trials using the introduced biocontrol agent Curinus coeruleus (Coccinellidae) demonstrated detection of Lepidoptera DNA fragments = 151 bp in 85-100% of beetles after 24 h digestion of an early instar larva. This study provides a framework for future use of molecular gut analysis in arthropod conservation ecology and food web research with considerable potential for quantifying threats to endemic species in Hawaii and elsewhere.

Amino Acid Sequence↗
PubMed2007

Genetic connectivity in the Florida reef system: comparative phylogeography of commensal invertebrates with contrasting reproductive strategies.

Effective spatial management of coral reefs including design of marine protected areas requires an understanding of interpopulation genetic connectivity. We assessed gene flow along 355 km of the Florida reef system and between Florida and Belize in three commensal invertebrates occupying the same host sponge (Callyspongia vaginalis) but displaying contrasting reproductive dispersal strategies: the broadcast-spawning brittle star Ophiothrix lineata and two brooding amphipods Leucothoe kensleyi and Leucothoe ashleyae. Multiple analytical approaches to sequence variation in the mitochondrial COI gene demonstrated a high degree of overall connectivity for all three species along the Florida reef system. Ophiothrix lineata showed significant genetic structuring between Florida and Belize, and a pattern of isolation by distance but no significant genetic structuring along the Florida coastline. Bayesian estimates of migration detected a strong southerly dispersal bias for O. lineata along the Florida reef system, contrary to the general assumption of northerly gene flow in this region based on the direction of the Florida Current. Both amphipods, despite direct development, also showed high gene flow along the Florida reef system. Multiple inferences of long-distance dispersal from a nested clade analysis support the hypothesis that amphipod transport, possibly in detached sponge fragments, could generate the high levels of overall gene flow observed. However, this transport mechanism appears much less effective across deep water as connectivity between Florida and Belize (1072 km) is highly restricted.

Amphipoda↗
PubMed1980

Evidence for an H-Y crossreactive antigen in invertebrates.

A sex specific antigen which crossreacts with the mammalian H-Y antigen has been identified on the cell surface of hemocytes from the lobster (Homarus americanus) and the gonadal cells of three insect species. The hemocytes from the male lobster, the testicular cells from the male beetle (P. cornutus), and the ovarian cells from two Orthopteran species (L. maderae and D. punctata) specifically absorbed H-Y antibodies. The specificity of H-Y antibody absorptions by cells from only one sex, suggest that an ancestral H-Y-like antigen may be present in invertebrates which could be engaged in sexual (cellular) recognition events.

Animals↗
PubMed1988

Induction of process outgrowth in vertebrate and invertebrate cell lines by a 2-pyridinyl thiosemicarbazone.

Regulation of differentiation in cells of disparate origin is often mediated by widely differing molecular signals and receptor mechanisms. For example, two neuron-like cell lines used extensively as models for molecular control of differentiation, the steroid-sensitive Kc line from Drosophila and the polypeptide- and cyclic nucleotide-sensitive PC12 line from rat, share no obvious growth factor or hormone receptors. However, we have found that a thiosemicarbazone, 1-pyrrolidinecarbothioic acid [1-(2-pyridinyl)ethylidene] hydrazide, one of a class of synthetic antineoplastic agents, induces process outgrowth - a marker of cellular differentiation - in cells of both of these lines. Moreover, the thiosemicarbazone induces process outgrowth in cells of mutant clones of these lines that are refractory to treatment with growth factors or hormones. Activity of the thiosemicarbazone is dependent upon the alpha-(N)-heterocyclic ring. These findings show that the 2-pyridinyl thiosemicarbazone mimics the effects of diverse epigenetic factors in inducing process outgrowth similar to that seen in cellular differentiation of these cell lines induced by natural regulators. Regulation may be by a mechanism, common to both invertebrate and vertebrate cells, which occurs downstream from the receptors that have been previously shown to mediate epigenetically induced differentiation.

Animals↗
PubMed1975

Studies on the role and mode of operation of the very-lysine-rich histones in eukaryote chromatin. The conformation of phi1 histones from marine invertebrate sperm.

Proton magnetic resonance, circular dichroism and infrared spectroscopy are used to investigate the secondary and tertiary structure of three very lysine-rich histones from marine invertebrate sperm. At high ionic strength both Arbacia lixula and Holothuria tubulosa histone phi 1 are observed to contain 25-30% alpha-helix, no beta-structure and to form specific folded structures. Both phi 1 proton magnetic resonance spectra have perturbed methyl resonances at chemical shifts close to those observed for calf thymus H1, suggesting analogies in tertiary structure. Mytilus edulis histone phi 1 however, shows no spectroscopic evidence of secondary and tertiary structure on salt addition.

Amino Acids↗
PubMed1976

Studies on the role and mode of operation of the very-lysine-rich histones in eukaryote chromatin. Nuclear-magnetic-resonance studies on nucleoprotein and histone phi 1-DNA complexes from marine invertebrate sperm.

Proton magnetic resonance and other measurements have been carried out in order to study the behaviour of the lysine-rich histones phi 1 in the sperm chromatin of certain marine invertebrates. Well defined particles (12 S) have been obtained from this chromatin by nuclease treatment. Chromatin solubility as a function of ionic strength shows a relaxation at salt concentrations higher than in the case of calf thymus nucleoprotein. Nuclear magnetic resonance (NMR) studies show that the release of histone from DNA occurs both in chromatin and in the reconstituted complexes at practically the same ionic strength as solubility relaxation. The higher the arginine content of a given phi 1, the higher the ionic strength at which both effects take place. The NMR results demonstrate that arginine residues are bound more strongly than lysine residues. The data overall show that phi 1 histones play a role in the contraction mechanism of sperm chromatin similar to that of H 1 histone in calf thymus chromatin. The highly contracted state of sperm chromatin is directly related to the increased arginine content of the phi 1 histone.

Animals↗
PubMed1993

LymnaDFamides, a new family of neuropeptides from the pond snail, Lymnaea stagnalis. Clue to cholecystokinin immunoreactivity in invertebrates?

Five tridecapeptides have been identified from the central nervous system of the pond snail, Lymnaea stagnalis. The sequences are Pro-Xaa-Asp-Arg-Ile-Ser-Yaa-Ser-Ala-Phe-Ser-Asp-Phe. NH2, where Xaa is either Tyr or Phe and Yaa either Asn, Ser or Gly. The peptides are named lymnaDFamides to acknowledge identity with the C-terminal dipeptide of the mammalian neuropeptides, cholecystokinin (CCK) and gastrin. They were detected by an antiserum that recognizes the biologically active C-termini of cholecystokinin and gastrin. LymnaDFamide-1 (Xaa = Tyr and Yaa = Asn) had no effect on trout gallbladder, which responds equally to CCK and gastrin. We propose that the lymnaDFamides belong to an Asp-Phe-amide superfamily, which includes CCK and gastrin, and suggest that the widespread CCK/gastrin immunoreactivity in invertebrates is due to peptides belonging to such a superfamily.

Amino Acid Sequence↗
PubMed1989

t-[35S]butylbicyclophosphorothionate binding sites in invertebrate tissues.

Specific high affinity binding of the cage convulsant t-[35S]butylbicyclophosphorothionate (TBPS) was observed in membrane homogenates of housefly heads and crayfish abdominal muscles. [35S]TBPS binding in these two invertebrate tissues was inhibited by biologically active cage convulsants, picrotoxin analogs, and barbiturates. The housefly binding sites were inhibited most potently by several insecticides. Approximately 50% of total binding was displaceable by excess (0.1 mM) nonradioactive TBPS, picrotoxinin, ethyl bicyclophosphate, or dieldrin. Optimal binding assay conditions for housefly homogenates included pH 7.5, 22 degrees C temperature, 0.3 M chloride concentration, and incubation for 60 min; for crayfish homogenates, 4 degrees C temperature and 150-min incubations were optimal. Scatchard plots of equilibrium binding indicated one site in both tissues (KD = 50 nM, Bmax = 250 fmol/mg protein in housefly; KD = 25 nM, Bmax = 100 fmol/mg protein in crayfish). Association kinetics in housefly were consistent with one rate constant (k+1 = 8 X 10(6) M-1 min-1), but dissociation was described better by two rate constants (k-1 = 0.28 min-1 and 0.042 min-1; calculated KD values of 80 nM and 12 nM). Displacement by cage convulsants showed Hill numbers near 0.5, also consistent with two populations of affinity, while displacement by other drugs showed Hill numbers near 1.0. [35S]TBPS binding in insects was most potently inhibited by the insecticides dieldrin (IC50 = 50 nM), aldrin, and lindane (200 nM), in a stereospecific manner, consistent with this binding site being the receptor for biological toxicity. [35S]TBPS binding was also inhibited by relatively high concentrations of some pyrethroid insecticides, such as deltamethrin and cypermethrin (1-2 microM).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2005

Characterization of a novel D2-like dopamine receptor with a truncated splice variant and a D1-like dopamine receptor unique to invertebrates from Caenorhabditis elegans.

We have cloned two novel Caenorhabditis elegans dopamine receptors, DOP-3 and DOP-4. DOP-3 shows high sequence homology with other D2-like dopamine receptors. As a result of alternative splicing, a truncated splice variant of DOP-3, DOP-3nf, was produced. Because of the in-frame insertion of a stop codon in the third intracellular loop, DOP-3nf lacks the sixth and seventh transmembrane domains that are found in the full-length DOP-3 receptor. Reporter gene assay showed that DOP-3 attenuates forskolin-stimulated cAMP formation in response to dopamine stimulation, whereas DOP-3nf does not. When DOP-3 was coexpressed with DOP-3nf, the ability to inhibit forskolin-stimulated cAMP formation was reduced. DOP-4 shows high sequence homology with D1-like dopamine receptors unique to invertebrates, which are distinct from mammalian D1-like dopamine receptors. Reporter gene assay showed that DOP-4 stimulates cAMP accumulation in response to dopamine stimulation. These two receptors provide new opportunities to understand dopaminergic signaling at the molecular level.

Amino Acid Sequence↗
PubMedDate not supplied

Expression of estrogen-receptor related receptors in amphioxus and zebrafish: implications for the evolution of posterior brain segmentation at the invertebrate-to-vertebrate transition.

Summary The evolutionary origin of vertebrate hindbrain segmentation is unclear since the amphioxus, the closest living invertebrate relative to the vertebrates, possesses a hindbrain homolog that displays no gross morphological segmentation. Three of the estrogen-receptor related (ERR) receptors are segmentally expressed in the zebrafish hindbrain, suggesting that their common ancestor was expressed in a similar, reiterated manner. We have also cloned and determined the developmental expression of the single homolog of the vertebrate ERR genes in the amphioxus (AmphiERR). This gene is also expressed in a segmented manner in a region considered homologous to the vertebrate hindbrain. In contrast to the expression of amphioxus islet (a LIM-homeobox gene that also labels motoneurons), AmphiERR expression persists longer in the hindbrain homolog and does not later extend to additional posterior cells. In addition, AmphiERR and one of its vertebrate homologs (ERRalpha) are expressed in the developing somitic musculature of amphioxus and zebrafish, respectively. Altogether, our results are consistent with fine structural evidence suggesting that the amphioxus hindbrain is segmented, and indicate that chordate ERR gene expression is a marker for both hindbrain and muscle segmentation. Furthermore, our data support an evolution model of chordate brain segmentation: originally, the program for anterior segmentation in the protochordate ancestors of the vertebrates resided in the developing axial mesoderm which imposed reiterated patterning on the adjacent neural tube; during early vertebrate evolution, this segmentation program was transferred to and controlled by the neural tube.

Amino Acid Sequence↗
PubMed1981

Altered invertebrate nerve function after chronic exposure to low concentrations of alcohol.

Previous studies of direct alcohol toxicity on nerve tissue have been carried out using acute, extremely high doses of alcohol. Chronic administration of 20 mM ethanol to the mollusc Aplysia californica was achieved by adding ethanol to surrounding seawater. Although the animals appeared healthy, isolated ganglion cells from treated animals had significantly decreased mean action potential amplitudes and prolonged mean action potential durations compared to controls. These findings suggest that chronic exposure to a low concentration of ethanol comparable to that producing drunkeness in humans may have a direct toxic effect on invertebrate nerve tissue.

Animals↗
PubMed1995

The subtilisins of the invertebrate mycopathogens Verticillium chlamydosporium and Metarhizium anisopliae are serologically and functionally related.

The major extracellular proteases from the nematophagous fungus Verticillium chlamydosporium and the entomophagous fungus Metarhizium anisopliae, VCP1 and Pr1, respectively, are closely related both functionally and serologically. Antibodies raised against either enzyme cross-reacted with both antigens, suggesting that they have common epitopes. The VCP1 and Pr1 antisera labelled bovine pancreatic elastase and proteinase K, respectively. Neither antiserum reacted with commercial chymotrypsin. An antiserum to a serine protease from the closely related V. suchlasporium also cross-reacted with VCP1 and Pr1. In contrast, a polyclonal antibody to an isoform of Pr1 exclusive to M. anisopliae isolate ME1 failed to recognize Pr1 from M. anisopliae V245 or VCP1. The N-terminal amino acid sequence of VCP1 revealed similarities with subtilisin-like enzymes from other fungi, but the closest match was with Pr1. The pure enzymes, VCP1 and Pr1, failed to hydrolyse mono-aminoacyl-naphthylamide substrates but demonstrated dipeptidyl peptidase activity against Gly-Pro-beta NA and Leu-Ala-beta NA, respectively. These results are discussed in the context of specificity of invertebrate mycopathogens.

Amino Acid Sequence↗
PubMed2005

Invertebrate models of Alzheimer's disease.

The intensely studied model organisms Caenorhabditis elegans and Drosophila melanogaster have been employed to study a number of neurodegenerative diseases, including Alzheimer's disease (AD). Although worms and flies are phylogenetically distant from humans, results of both classic genetic analyses and transgenic manipulation of these invertebrates suggest they are valid models for at least some aspects of AD. This review describes the rationale for AD-relevant studies in worms and flies and discusses both what has been learned from these studies and what may be discovered in the future.

Alzheimer Disease↗
PubMed2004

The cryptic filtering house of an invertebrate larva.

Planktonic larvae of the annelid Pectinaria californiensis construct and inhabit cryptic houses through which they filter seawater to concentrate food. Although filtering houses may be unique to pectinariid larvae, other transparent and ephemeral structures are secreted by the larvae of many marine invertebrates and may be involved in the performance of a variety of critical larval functions.

Animals↗
PubMed2005

Nutrient-specific foraging in invertebrate predators.

Many herbivores and omnivores adjust their food selection behavior to regulate the intake of multiple nutrients. Carnivores, however, are generally assumed to optimize the rate of prey capture rather than select prey according to nutrient composition. We showed experimentally that invertebrate predators can forage selectively for protein and lipids to redress specific nutritional imbalances. This selection can take place at different stages of prey handling: The predator may select among foods of different nutritional composition, eat more of a prey if it is rich in nutrients that the predator is deficient in, or extract specific nutrients from a single prey item.

Animals↗
PubMed2005

Soil invertebrates disrupt carbon flow through fungal networks.

Annual carbon flux through soil respiration is ten times greater than fossil fuel combustion, but its component parts are poorly understood because they are the product of complex multitrophic interactions between soil organisms. A major component of carbon flux from plants to soil occurs through networks of symbiotic arbuscular mycorrhizal fungi. Here, using 13CO2 pulse labeling, we show that natural densities of the numerically dominant fungal feeding invertebrate Protaphorura armata (order Collembola) reduces 13C enrichment of mycorrhizosphere respiration by 32%. Our findings emphasize the importance of multitrophic interactions in regulating respiration of recent plant photosynthate from soil.

Animals↗