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At least 847 records · Page 47Linked to original sources
PubMed2001

Antennal SNMPs (sensory neuron membrane proteins) of Lepidoptera define a unique family of invertebrate CD36-like proteins.

SNMP1-Apol is an antennal-specific protein of the wild silk moth Antheraea polyphemus; the protein is abundantly expressed and localized to the receptor membranes of sex-pheromone specific olfactory sensory neurons (OSNs). SNMP1-Apol is thought to function in odor detection based on its olfactory-specific expression, localization within OSNs, developmental time of expression, and apparent homology to the CD36 family of membrane-bound receptor proteins. In the current study, SNMP1-Apol homologues were identified from the moths Bombyx mori, Heliothis virescens, and Manduca sexta. These species posses antennal mRNAs encoding proteins with amino acid sequence identities ranging from 75-80%; these proteins are collectively designated SNMP1. A second M. sexta SNMP homologue, previously identified and partially sequenced [Robertson et al.: Insect Mol Biol 8:501-518, 1999] was fully sequenced and characterized. The encoded protein shares only 26-27% sequence identity with the SNMP1 proteins, and is thus designated SNMP2-Msex. The SNMP sequences were used to identify 14 and four possible homologues in Drosophila melanogaster and Caenorhabditis elegans genome databases, respectively; thus, greatly expanding CD36 family membership among the invertebrate lineages. Despite their sequence difference, SNMP1-Msex and SNMP2-Msex expression is localized to OSNs and occurs simultaneously with the onset of olfactory function. These findings suggest that SNMPs play a central role in odor detection in insects, and that the CD36 gene family is widely represented among animal phyla. The SNMPs are the only identified neuronal members of the CD36 family, and as such expand the activities of this gene family into roles influencing brain function and behavioral action.

Aging↗
PubMed2004

Analysis of uranium and isotopic ratio measurement in fish and marine invertebrates from the North Adriatic Sea by inductively coupled plasma mass spectrometry.

Uranium analysis in fish, echinoderms and shellfish samples collected in the north part of the Adriatic Sea is presented. The aim of the work was to evaluate uranium concentrations in samples of this kind, and also to investigate possible contamination from depleted uranium (DU) in consequence of the war operations previously conducted in that area. DU contamination was checked by measuring the (235)U/(238)U isotope ratio. The samples were dissolved according to the EPA 3052 procedure, and the determinations were performed by inductively coupled plasma mass spectrometry (ICP-MS), optimized in order to perform isotope ratio measurements with good precision. The method was validated by evaluating the recovery from spiked samples; results in the range 93-107% were obtained. The isotope ratio measurement was evaluated in terms of accuracy and precision by analyzing the certified reference materials IAEA 326 and GBW 07305, and good agreement with the certified values was obtained here also. The concentration of uranium was higher in invertebrate samples than in fish (0.3-2 microg/g of U vs. 0.05-0.1 microg/g, respectively). The isotope ratio measurements for all the samples gave values very similar to the natural ratio, permitting exclusion of the presence of DU.

Animals↗
PubMed2004

Defense systems of benthic invertebrates in response to environmental stressors.

Environmental stress factors may be responsible for biological changes in living species that are able to overcome deleterious effects depending on their detoxifying capacities. Defense systems present in every living species are involved in elimination of reactive chemical species of endogenous or exogenous origin, neutralization of their effects, repair of initial lesions, and compensation of deficient metabolic pathways. Consequently, the performance of defense systems and their inducibility will explain adaptation to environmental disturbances, whereas their alteration will augur toxicity in the exposed species. Several field studies have illustrated the relationships between antioxidants and toxicity in benthic invertebrates in rivers. They highlighted that defense systems may be useful biomarkers in mechanistic studies of ecotoxicity and in the biomonitoring of living species in polluted environments.

Adaptation, Physiological↗
PubMed1997

Protein kinases in mitochondria of the invertebrate Artemia franciscana.

The information concerning protein kinases in animal mitochondria is scarce and related only to mammals. No data are available for invertebrates. We demonstrate here the presence of casein kinase II (CK II) and cAMP-dependent protein kinase (PKA) in the purified mitochondria of the crustacean Artemia franciscana. Whereas the mitochondrial CK II showed the same characteristics of the cytosolic enzyme, mitochondrial PKA had an apparent Km for its substrate Kemptide 1 order of magnitude lower than that of the cytosolic enzyme. CK II and PKA phosphorylate different sets of proteins in Artemia mitochondria in vitro. The use of an activity gel assay has allowed the detection of additional protein kinases, as yet unidentified, in Artemia mitochondria.

Animals↗
PubMed2002

Chemoenzymatic synthesis of peptidyl 3,4-dihydroxyphenylalanine for structure-activity relationships in marine invertebrate polypeptides.

An improved method for hydroxylating tyrosine-containing sequences in polypeptides to peptidyl 3,4-dihydroxyphenylalanine (DOPA) using mushroom tyrosinase at relatively high enzyme-to-substrate ratios is described. The new method involves incorporating borate into the reaction mixture to stop formation of the unwanted side product 3,4,5-trihydroxyphenylalanine. Using this method, a model for the palindromic central sequence for the antimicrobial peptide family, the styelins, Y*Y*KHKY*Y* (where Y* is DOPA), was successfully synthesized in high yield from YYKHKYY. This sequence represents a particularly challenging target because of the cluster of four precursor tyrosine residues are in close proximity. The method should be readily applied to larger polypeptides produced by either solid-phase synthesis or recombinant techniques and give greater insight into the roles of this unusual posttranslational modification in marine invertebrates such as mussels and ascidians.

Animals↗
PubMed1997

Effects of birds on the intensity of ant rain: a terrestrial form of invertebrate drift

Large numbers of wood ants, Formica aquiloniacrawl up trees to gather food (arthropods and honeydew), and most return to the ground the same way. A small but noticeable percentage, however, returns to the ground by falling. This continuous rain of free-falling ants, from trees to the ground, is analogous to the drift of invertebrates in freshwater streams, and provides ecologists with an easily replicated terrestrial system for studying the phenomenon of drift. In a field experiment in this system, when birds came to forage, the total numbers and percentages of ants entering the rain increased dramatically. Initial background levels of ant rain (before birds came to forage) ranged from 0 to 11.9% (X=4.0%). When birds came to forage in certain trees, the percentage of ants entering the rain in those trees ranged from 2.9 to 28.4% (X=9.1%). In trees not visited by birds, ant rain decreased slightly during the same period to a mean of 3.7%. As the total time birds spent foraging in a tree increased, ant rain there also increased.

Journal Article↗
PubMed2000

Neutral endopeptidase-24.11 (NEP) deactivates PDGF- and TGF-beta-induced cell shape changes in invertebrate immunocytes.

Using a cytofluorimetric assay, we found that immunocytes of the mollusc, Mytilus galloprovincialis, express CD10, a surface antigen known to be identical to neutral endopeptidase-24.11 (NEP). The spectrofluorimetric analysis demonstrates that the growth factors PDGF-AB and TGF-beta1 provoke an increase in NEP-like activity in membrane preparations from the immunocytes, but have no effect on the soluble form in the serum. On the other hand, computer-assisted microscopic image analysis reveals that NEP deactivates the PDGF-AB- and TGF-beta1-induced shape changes in immunocytes. However, Western blots show that, in solution, NEP does not cleave PDGF-AB or TGF-beta1, indicating that the inactivation is not due to proteolysis. These results suggest a functional interplay in invertebrate immunocytes between growth factors and NEP, as previously shown in vertebrate cells.

Animals↗
PubMed2000

Evolutionary conservation of the presumptive neural plate markers AmphiSox1/2/3 and AmphiNeurogenin in the invertebrate chordate amphioxus.

Amphioxus, as the closest living invertebrate relative of the vertebrates, can give insights into the evolutionary origin of the vertebrate body plan. Therefore, to investigate the evolution of genetic mechanisms for establishing and patterning the neuroectoderm, we cloned and determined the embryonic expression of two amphioxus transcription factors, AmphiSox1/2/3 and AmphiNeurogenin. These genes are the earliest known markers for presumptive neuroectoderm in amphioxus. By the early neurula stage, AmphiNeurogenin expression becomes restricted to two bilateral columns of segmentally arranged neural plate cells, which probably include precursors of motor neurons. This is the earliest indication of segmentation in the amphioxus nerve cord. Later, expression extends to dorsal cells in the nerve cord, which may include precursors of sensory neurons. By the midneurula, AmphiSox1/2/3 expression becomes limited to the dorsal part of the forming neural tube. These patterns resemble those of their vertebrate and Drosophila homologs. Taken together with the evolutionarily conserved expression of the dorsoventral patterning genes, BMP2/4 and chordin, in nonneural and neural ectoderm, respectively, of chordates and Drosophila, our results are consistent with the evolution of the chordate dorsal nerve cord and the insect ventral nerve cord from a longitudinal nerve cord in a common bilaterian ancestor. However, AmphiSox1/2/3 differs from its vertebrate homologs in not being expressed outside the CNS, suggesting that additional roles for this gene have evolved in connection with gene duplication in the vertebrate lineage. In contrast, expression in the midgut of AmphiNeurogenin together with the gene encoding the insulin-like peptide suggests that amphioxus may have homologs of vertebrate pancreatic islet cells, which express neurogenin3. In addition, AmphiNeurogenin, like its vertebrate and Drosophila homologs, is expressed in apparent precursors of epidermal chemosensory and possibly mechanosensory cells, suggesting a common origin for protostome and deuterostome epidermal sensory cells in the ancestral bilaterian.

Amino Acid Sequence↗
PubMed1996

Toxicity of organotin compounds on embryos of a marine invertebrate (Styela plicata; tunicata).

In order to clarify the interaction mechanism between organotin compounds and organisms, the effects of these compounds on the development of a benthonic filter-feeding invertebrate were studied. Embryos of the ascidian Styela plicata were obtained in laboratory by cross-fertilization and their development was followed in vivo after incubation with 0.1, 1, and 10 microM organotin compounds for various exposure times. Moreover, embryos selected at opportune stages after incubation with 10 microM tributyltin (TBT) or triphenyltin (TPT) for 1 hr were observed at the electron microscope to recognize cell alterations. Results indicate that organotins significantly affect all stages of ascidian development in a dose- and time-dependent manner and the most sensitive stages are gastrula and neurula. These compounds are able to block development, giving rise to anomalous embryos with irreversible effects. The order of inhibition appears to be strongly dependent on the organotin liposolubility: TBT > dibutyltin (DBT) > monobutyltin (MBT) and TPT > tricyclohexyltin (TCHT). The mitosis block of blastomeres in the early stages may be related to an inhibition of the microtubule polymerization. Observations with light and electron microscopes reveal globeshaped blastomeres with large intercellular spaces in the morula and gastrula stages, suggesting a toxic damage with alteration of the cytoskeleton. Moreover, the occurrence of electron-dense precipitates of organotins in the inner membrane of mitochondria and morphological changes of their cristae suggest an inhibitory effect on oxidative phosphorylation which is conspicuous in the gastrula stage. In this stage, the size of the electron-dense aggregates grow from 50-70 to 110-170 nm, while at the same time the alteration of the cristae increases.

Animals↗
PubMed1997

Nontarget effects of neem-based insecticides on aquatic invertebrates.

Neem-based insecticides are being investigated as alternatives to synthetic insecticides for the control of forest insect pests in Canada. Because the proposed use pattern against forest defoliators often necessitates spraying near shoreline areas, an assessment of adverse effects of neem on nontarget aquatic invertebrates was warranted. Acute lethal effects of two neem-based formulations on eight species of macroinvertebrates were determined in flow-through screening tests at 10 times the expected environmental concentration (0.35 mg/liter). Significant mortality occurred only in the mayfly Isonychia bicolor/rufa exposed to one formulation, and further tests were conducted to determine a concentration-dependent response. The LC50 for I. bicolor/rufa was estimated at 1.12 mg/liter; the LC10 was 0.63 mg/liter. Three detritivorous species were tested at expected environmental concentrations (0.035 mg/liter) at longer exposures in aquatic microcosms to determine effects of the two formulations on feeding rates and survival. Neither formulation caused significant mortality or antifeedant effects after a 28-day exposure. The implications of these results for forest pest management operations are discussed.

Animals↗
PubMed1994

Myoendocrine-like cells in invertebrates: occurrence of noncardiac striated secretory-like myocytes in the gut of the ant Formica polyctena.

The occurrence of myoendocrine-like cells investing the ampullar draining region of Malpighian tubules and neighboring midgut and hindgut regions of the ant Formica polyctena is reported. These striated muscle cells show small electron-dense endocrine-like granules (130 +/- 0.95 nm) in addition to myofilaments and ordinary organules of the myocytes. Apart from their contractile function, such ultrastructural features suggest a regulatory role for these cells, as is the case of vertebrate myoendocrine cells. As far as we know, the ant secretory myocytes reported here constitute the first description of myoendocrine cells among invertebrates, as well as the first report of secretory, striated muscle cells outside the heart in the animal kingdom.

Animals↗
PubMed1997

Linkage of TATA-binding protein and proteasome subunit C5 genes in mice and humans reveals synteny conserved between mammals and invertebrates.

The TATA-binding protein (TBP) is a factor required for the transcription of all classes of eukaryotic genes. Here, we demonstrate that in the mouse the TBP-encoding gene (Tbp) resides next to the proteasomal subunit C5-encoding gene (Psmb1). The genes are located on mouse chromosome 17 in the t complex within the Hybrid sterility 1 (Hst1) region. We demonstrate that the homologous human genes (TBP AND PSMB1) are tightly linked on the long arm of chromosome 6, in a region syntenic with the proximal part of mouse chromosome 17. The mouse Tbp and Psmb1 and the human TBP and PSMB1 genes are transcribed in the opposite orientation. The TATA-binding protein and proteasomal subunit C5 genes are also linked on chromosome III of Caenorhabditis elegans, and together they are linked to other genes whose homologs map to human chromosome 6 and mouse chromosome 17. In the Drosophila genome, the housekeeping TATA-binding protein gene maps close to two other genes with homologs in the mammalian major histocompatibility complex. There thus exists conserved synteny of unrelated genes between mammals and invertebrates.

Animals↗
PubMed1998

Assembly and architecture of invertebrate cytoplasmic intermediate filaments reconcile features of vertebrate cytoplasmic and nuclear lamin-type intermediate filaments.

The two major intermediate filament (IF) proteins from the esophagus epithelium of the snail Helix pomatia and the two major IF proteins from muscle tissue of the nematode Ascaris suum were investigated under a variety of assembly conditions. The lowest-order complexes from each of the four protostomic invertebrate (p-INV) IF proteins are parallel, unstaggered dimers involving two-stranded alpha-helical coiled coil formation of their approximately 350 amino acid residue central rod domain (i.e. long-rod). In the electron microscope these are readily recognized by their distinct approximately 56 nm long rod with two globular domains (i.e. representing the non-helical carboxy-terminal tail domain of the p-INV IF proteins) attached at one end, closely resembling vertebrate lamin dimers. The next-higher-order oligomers are tetramers, which are easily recognized by their two pairs of globular tail domains attached at either end of a approximately 72 nm long central rod portion. According to their size and shape, these tetramers are built from two dimers associated laterally in an antiparallel, approximately half-staggered fashion via the amino-terminal halves of their rod domains. This is similar to the NN-type tetramers found as the most abundant oligomer species in all types of vertebrate cytoplasmic IF proteins, which contain a approximately 310 amino acid residue central rod domain (i.e. short-rod). As a first step toward filament formation, the p-INV IF tetramers anneal longitudinally into protofilaments by antiparallel CC-type association of the carboxy-terminal halves of their dimer rods. The next step involves radial growth, occurring initially through lateral association of two four-chain protofilaments into octameric subfibrils, which then further associate into mature, full-width filaments. Head-to-tail polymers of dimers and paracrystalline fibers commonly observed with vertebrate lamins were only rarely seen with p-INV IF proteins. The globular domains residing at the carboxy-terminal end of p-INV IF dimers were studding the surface of the filaments at regular, approximately 24.5 nm intervals, thereby giving them a "beaded" appearance with an axial periodicity of about 24.5 nm, which is approximately 3 nm longer than the corresponding approximately 21.5 nm repeat pattern exhibited by short-rod vertebrate IFs.

Animals↗
PubMedDate not supplied

Projection structure of an invertebrate rhodopsin.

Rhodopsin is the G-protein-coupled membrane receptor that initiates the visual transduction cascade in retinal photoreceptors. In the present study rhodopsin from the dark-adapted retinas of squid (Loligo forbesi) was detergent-extracted, purified, and reconstituted into native squid photoreceptor lipids following proteolytic cleavage of its prolinerich C-terminus. Two-dimensional crystals of C-terminally truncated rhodopsin reconstituted from octyl glucoside solution formed in a p222(1) lattice (a = 44 A, b = 131 A). Electron micrographs of frozen-hydrated crystals were processed and a projection structure to 8 A resolution was calculated. The projection map obtained is very similar to maps previously determined for bovine and frog rhodopsins although the crystal packing of the molecules is quite different. Comparison of the maps shows that the arrangement of alpha-helices in the proteins is very similar despite their great phylogenetic distance; this structure is likely to be present in the whole superfamily of G-protein-coupled receptors. Invertebrate rhodopsins have a large insertion in the helix 5-helix 6 loop. Assignment of an additional density in the squid rhodopsin map to this region supports a previously proposed helix assignment and identifies the end-to-end contacts as helices 1 and 5.

Animals↗
PubMed2000

2-arachidonyl-glycerol stimulates nitric oxide release from human immune and vascular tissues and invertebrate immunocytes by cannabinoid receptor 1.

The pharmacological physiological effects of the endogenous cannabinomimetic (endocannabinoid) anandamide have been well characterized. Another endocannabinoid, 2-arachidonoyl-glycerol (2-AG), has been less-widely studied. 2-AG occurs in vertebrate and invertebrate tissues and binds to both cannabinoid receptors (CB1 and CB2). In the current study, 2-AG was found to cause human monocytes and immunocytes from Mytilus edulis to become round and immobile, which may correlate with decreased production of cytokines and adhesion molecules, i.e. an immunosuppressive response. In addition, exposure of these cells to 2-AG results in nitric oxide (NO) release, which is blocked by the nitric oxide synthase inhibitor, l-NAME and a CB1 antagonist, but not by a CB2 antagonist. The results obtained in the human vascular system were similar to those obtained in immune cells. Treatment of human saphenous veins and atria with 2-AG stimulated basal NO release, which was antagonized by l-NAME and a CB1 antagonist. Taken together these results indicate that 2-AG exerts immune and vascular actions similar to those observed with anandamide.

Adjuvants, Immunologic↗
PubMed1979

Physiological and chemical characterization of invertebrate metallothionein-like proteins.

Metallothionein-like proteins have been isolated from marine invertebrates. Three crustaceans, Scyllus serratus, Cancer magister and Acetes sibogae together with a mollusc, Cryptochiton stelleri, have been investigated. S. serratus hepatopancreas was shown to contain cadmium and zinc inducible metallothionein-like proteins with an amino acid analysis very similar to vertebrate metallothioneins. The molecular weight, ultra-violet spectrum and isoelectric points of S. serratus metallothioneins are also comparable to the vertebrate proteins, suggesting a fundamental biological function conserved throughout evolution.

Amino Acids↗
PubMed1990

Comparison of the immunological properties of mammalian (rodent), bird, fish, amphibian (toad), and invertebrate (crab) metallothioneins.

Immunoassays such as rocket immunoelectrophoresis, western dot blot hybridization, and competitive ELISA analysis were used to estimate and compare homology among fishes (several species), crab, toad, chicken and rodent metallothioneins. The relative abundance of tissue-specific metallothionein in catfish was highest in liver followed by kidney and pancreas like mammalian systems. Immunologically, considerable homology exists among fish metallothioneins, although the extent of homology differs to some extent. No homology was found between fish or chicken metallothioneins. The amphibian (toad) and invertebrate (crab) metallothioneins showed only partial homology with fish metallothioneins in antigenic determinants.

Amphibians↗
PubMed1979

Hybrid pigment organelles in an invertebrate.

Observations of a number of vertebrate chromatophores have revealed the presence of more than one type of pigment organelles, suggesting that the different types are all derived from an equipotential organelle able to differentiate into any of the major pigment-containing organelles (Bagnara, 1972). Observations are presented concerning the occurrence of hybrid pigment inclusions, i.e., all kinds of intergrades between melanosomes, pterinosomes, and reflecting platelets in pigment cells of the daddy-long-legs. It therefore seems possible that pigment organelles in some invertebrates may also be derived from a common pluripotential primordial organelle.

Animals↗