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At least 19 recordsLinked to original sources
PubMed1993

Invertebrate cytokines. III: Invertebrate interleukin-1-like molecules stimulate phagocytosis by tunicate and echinoderm cells.

Phagocytosis is the predominant defense mechanism of invertebrates. Here we show that phagocytosis by echinoderm bladder amoebocytes and tunicate granular amoebocytes can be enhanced by invertebrate interleukin-1-like molecules. As little as 5 ng/ml of invertebrate interleukin-1 produced a significant stimulation of echinoderm and tunicate amoebocyte phagocytosis. Stimulation of phagocytosis by echinoderm interleukin-1-like molecules was inhibited by antisera to vertebrate interleukin-1. Invertebrate interleukin-1 also acted as an opsonin when preincubated with erythrocytes or yeast. In addition, the cellular mechanisms of invertebrate phagocytosis were studied using pharmacologic agents to inhibit echinoderm amoebocyte phagocytosis. The energy requirements and involvement of cellular cytoskeletal elements in phagocytosis by bladder amoebocytes were similar to those of mammalian macrophages. These results demonstrate a role for interleukin-1 in invertebrate host defense mechanisms.

Animals↗
PubMed2003

Invertebrate responses to the management of genetically modified herbicide-tolerant and conventional spring crops. I. Soil-surface-active invertebrates.

The effects of herbicide management of genetically modified herbicide-tolerant (GMHT) beet, maize and spring oilseed rape on the abundance and diversity of soil-surface-active invertebrates were assessed. Most effects did not differ between years, environmental zones or initial seedbanks or between sugar and fodder beet. This suggests that the results may be treated as generally applicable to agricultural situations throughout the UK for these crops. The direction of the effects was evenly balanced between increases and decreases in counts in the GMHT compared with the conventional treatment. Most effects involving a greater capture in the GMHT treatments occurred in maize, whereas most effects involving a smaller capture were in beet and spring oilseed rape. Differences between GMHT and conventional crop herbicide management had a significant effect on the capture of most surface-active invertebrate species and higher taxa tested in at least one crop, and these differences reflected the phenology and ecology of the invertebrates. Counts of carabids that feed on weed seeds were smaller in GMHT beet and spring oilseed rape but larger in GMHT maize. In contrast, collembolan detritivore counts were significantly larger under GMHT crop management.

Agriculture↗
PubMed1986

The myth of the inflexible invertebrate: competition and synaptic remodelling in the development of invertebrate nervous systems.

As this quote and the article it was taken from reflect, it is a commonly held belief that the development of invertebrate nervous systems is so rigidly programmed that it is qualitatively different from that of vertebrates. The facts do not support this assertion, and I will show, using examples from among the arthropods, that appropriate experiments often reveal competition, feedback, and prolonged periods of malleability much as they do for the vertebrates. Indeed, given the well known advantages of studying the invertebrate nervous system, I think it likely that invertebrates can serve as important and useful preparations for studying, at the cellular level, the same biological phenomena that Easter et al. (1985) are trying to understand in vertebrates.

Animals↗
PubMed1997

Evidence for the microbial basis of a chemoautotrophic invertebrate community at a whale fall on the deep seafloor: bone-colonizing bacteria and invertebrate endosymbionts.

To explore the microbial basis for a remarkable macrofaunal community at the site of a whale skeleton on the seafloor of the Santa Catalina Basin, we obtained samples of whale bone, bone-colonizing invertebrates, microbial mats, and the dominant fauna in the adjacent sulfide-rich sediments during Alvin expeditions in 1988 and 1991. Invertebrate tissues were examined by transmission electron microscopy (TEM) and mats and bone-penetrating bacteria by epifluorescence microscopy (EM). Tissues from the dominant bivalve Vesicomya c.f. gigas, the mytilid mussel Idasola washingtonia, and selected gastropods and limpets were also assayed chemically for enzymes diagnostic of sulfur- and methane-based chemoautotrophy and for stable carbon isotopic composition. Results of all analyses were consistent with dominant sulfur-based endosymbioses in the clam and mussel (the first record of endosymbiosis in the genus Idasola) and the general absence of methane symbioses at the site, strengthening the analogy of the whale-skeleton faunal community to those known from distant Pacific hydrothermal vent sites. Examples of minor endosymbionts, either nitrifying or methanotrophic cells according to internal membrane structures by TEM, raised the possibility of a supplemental mode of nutrition to the clam, or means to remove ammonia in the gill tissue, in the event of significant changes in the chemical environment.

Animals↗
PubMed2001

The gene of chlamysin, a marine invertebrate-type lysozyme, is organized similar to vertebrate but different from invertebrate chicken-type lysozyme genes.

In a recent publication we reported the protein purification, characterization, and the gene isolation of a cDNA encoding the antibacterial cold-active lysozyme-like protein chlamysin from the marine bivalve Chlamys islandica. A 4.2 kb genomic chlamysin gene has now been amplified and sequence-analyzed. By comparison to the cDNA sequence and its translation product, the coding region was found separated in four exons of 38-252 bp. The introns range in size from 0.8 to 1.5 kb, and have traditional spliceosomal intron 5'-GT donor and 3'-AG acceptor sites for splicing. Two of the introns contain multiple copies of three sequence motifs not found repeated in other published genes. The over-all gene organization of chlamysin resembles chicken-type (c-type) lysozyme genes in vertebrates, but is different from the three-exon structure in invertebrate c-type lysozyme genes. A phylogenetic analysis of invertebrate-type (i-type) and c-type lysozyme proteins demonstrated a large evolutionary distance between the i-type and the c-type enzyme classes. Exons of the i-type genes are not equally organized according to their homolog protein domains.

Amino Acid Sequence↗
PubMed2004

On the evolutionary origin of cyclooxygenase (COX) isozymes: characterization of marine invertebrate COX genes points to independent duplication events in vertebrate and invertebrate lineages.

In vertebrates, COX-1 and COX-2, two cyclooxygenase isozymes with different physiological functions and gene regulation, catalyze identical reactions in prostaglandin synthesis. It is still not understood why there are multiple forms of COX enzyme in the same cell type and when the evolutionary duplication of the COX gene occurred. Here we report the structure of two genes encoding for COX isozymes in the coral Gersemia fruticosa, the first non-vertebrate organism from which a cyclooxygenase was characterized. Both genes are about 20 kb in size and consist of nine exons. Intron/exon boundaries are well conserved between coral and mammalian COX genes. mRNAs of the previously reported G. fruticosa COX-A (GenBank trade mark accession number AY004222) and the novel COX-B share 94% sequence identity in the coding regions and less than 30% in the 5'- and 3'-untranslated region. Transcripts of both COX genes are detectable in coral cells, although the transcriptional level of COX-A is 2 orders of magnitude higher than COX-B. Expression of both coral genes in mammalian cells gave functional proteins with similar catalytic properties. By data base analyses we also detected and constructed different pairs of COX genes from the primitive chordates, Ciona savignyi and Ciona intestinalis. These two gene pairs encode proteins with 50% intra-species and only 70% cross-species sequence identity. Our results suggest that invertebrate COX gene pairs do not correspond to vertebrate COX-1 and COX-2 and are consistent with duplication of the COX gene having occurred independently in corals, ascidians, and vertebrates. It is evident that due to the importance and complexity of its regulatory role, COX has multiple isoforms in all organisms known to express it, and the genes encoding for the isozymes may to be regulated differently.

Amino Acid Sequence↗
PubMed1993

Opiate-like substances in an invertebrate, an opiate receptor on invertebrate and human immunocytes, and a role in immunosuppression.

The presence of morphine-like and codeine-like substances was demonstrated in the pedal ganglia, hemolymph, and mantle tissues of the mollusc Mytilus edulis. The pharmacological activities of the endogenous morphine-like material resemble those of authentic morphine. Both substances were found to counteract, in a dose-dependent manner, the stimulatory effect of tumor necrosis factor alpha or interleukin 1 alpha on human monocytes and Mytilus immunocytes, when added simultaneously to the incubation medium. The immunosuppressive effect of this opiate material expresses itself in a lowering of chemotactic activity, cellular velocity, and adherence. Codeine mimics the activity of authentic morphine, but only at much higher concentrations. Specific high-affinity receptor sites (mu 3) for morphine have been identified on human monocytes and Mytilus immunocytes. In Mytilus recovering from experimentally induced stress, the return of "altered" immunocytes to a more inactive state appears to be due to a significant rise in the content of morphine-like material in the pedal ganglia and hemolymph at this time. Thus, morphine may have a role in calming or terminating the state of immune alertness.

Animals↗
PubMed2002

A novel invertebrate trophic factor related to invertebrate neurotrophins is involved in planarian body regional survival and asexual reproduction.

Trophic factors are a heterogeneous group of molecules that promote cell growth and survival. In freshwater planarians, the small secreted protein TCEN49 is linked to the regional maintenance of the planarian central body region. To investigate its function in vivo, we performed loss-of-function and gain-of-function experiments by RNA interference and by the implantation of microbeads soaked in TCEN49, respectively. We show that TCEN49 behaves as a trophic factor involved in central body region neuron survival. In planarian tail regenerates, tcen49 expression inhibition by double-stranded RNA interference causes extensive apoptosis in various cell types, including nerve cells. This phenotype is rescued by the implantation of microbeads soaked in TCEN49 after RNA interference. On the other hand, in organisms committed to asexual reproduction, both tcen49 mRNA and its protein are detected not only in the central body region but also in the posterior region, expanding from cells close to the ventral nerve chords. In some cases, the implantation of microbeads soaked in TCEN49 in the posterior body region drives organisms to reproduce asexually, and the inhibition of tcen49 expression obstructs this process, suggesting a link between the central nervous system, TCEN49, regional induction, and asexual reproduction. Finally, the distribution of TCEN49 cysteine and tyrosine residues also points to a common evolutionary origin for TCEN49 and molluscan neurotrophins.

Amino Acid Sequence↗
PubMed2004

Invertebrate eggs can fly: evidence of waterfowl-mediated gene flow in aquatic invertebrates.

Waterfowl often have been assumed to disperse freshwater aquatic organisms between isolated wetlands, but no one has analyzed the impact of this transport on the population structure of aquatic organisms. For three cladocerans (Daphnia ambigua, Daphnia laevis, and Sida crystallina) and one bryozoan (Cristatella mucedo), we estimated the genetic distances between populations across North America using sequences of several mitochondrial DNA genes and genotypic frequencies at allozyme and microsatellite loci. Waterfowl movements across North America (estimated from band recovery data) explained a significant proportion of the gene flow occurring between populations across the continent for three of the four species, even after controlling for geographic distances between localities. The fourth species, S. crystallina, has propagules less likely to survive desiccation or ingestion by birds. Differences in the capacity to exploit bird-mediated transport are likely to have important consequences for the ecology of aquatic communities and the spread of invasive species.

Animal Migration↗
PubMed2001

Crystallization and preliminary crystallographic study of an invertebrate C-type lectin, CEL-I, from the marine invertebrate Cucumaria echinata.

CEL-I is a GalNAc-specific carbohydrate-binding protein (lectin) isolated from the sea cucumber Cucumaria echinata. This protein belongs to the widely distributed C-type lectin family of animal lectins, which require Ca(2+) for their carbohydrate-binding ability and play important roles in various molecular-recognition processes in organisms. CEL-I was crystallized with 2-methyl-2,4-pentanediol using the hanging-drop vapour-diffusion technique. The CEL-I crystals belong to the monoclinic space group C2, with unit-cell parameters a = 92.38 (3), b = 69.94 (3), c = 76.69 (3) A, beta = 136.46 (2) degrees. Diffraction data were collected to 2.0 A resolution using synchrotron radiation. The asymmetric unit contains one CEL-I molecule.

Animals↗
PubMed1990

Phototransduction: different mechanisms in vertebrates and invertebrates.

The photoreceptor cells of invertebrate animals differ from those of vertebrates in morphology and physiology. Our present knowledge of the different structures and transduction mechanisms of the two animal groups is described. In invertebrates, rhodopsin is converted by light into a meta-rhodopsin which is thermally stable and is usually re-isomerized by light. In contrast, photoisomerization in vertebrates leads to dissociation of the chromophore from opsin, and a metabolic process is necessary to regenerate rhodopsin. The electrical signals of visual excitation have opposite character in vertebrates and invertebrates: the vertebrate photoreceptor cell is hyperpolarized because of a decrease in conductance and invertebrate photoreceptors are depolarized owing to an increase in conductance. Single-photon-evoked excitatory events, which are believed to be a result of concerted action (the opening in invertebrates and the closing in vertebrates) of many light-modulated cation channels, are very different in terms of size and time course of photoreceptors for invertebrates and vertebrates. In invertebrates, the single-photon events (bumps) produced under identical conditions vary greatly in delay (latency), time course and size. The multiphoton response to brighter stimuli is several times as long as a response evoked by a single photon. The single-photon response of vertebrates has a standard size, a standard latency and a standard time course, all three parameters showing relatively small variations. Responses to flashes containing several photons have a shape and time scale that are similar to the single-photon-evoked events, varying only by an amplitude scaling factor, but not in latency and time course. In both vertebrate and invertebrate photoreceptors the single-photon-evoked events become smaller (in size) and faster owing to light adaptation. Calcium is mainly involved in these adaptation phenomena. All light adaptation in vertebrates is primarily, or perhaps exclusively, attributable to calcium feedback. In invertebrates, cyclic AMP (cAMP) is apparently another controller of sensitivity in dark adaptation. The interaction of photoexcited rhodopsin with a G-protein is similar in both vertebrate and invertebrate photoreceptors. However, these G-proteins activate different photoreceptor enzymes (phosphodiesterases): phospholipase C in invertebrates and cGMP phosphodiesterase in vertebrates. In the photoreceptors of vertebrates light leads to a rapid hydrolysis of cGMP which results in closing of cation channels. At present, the identity of the internal terminal messenger in invertebrate photoreceptors is still unsolved.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed2004

Invertebrate immune systems--not homogeneous, not simple, not well understood.

The approximate 30 extant invertebrate phyla have diversified along separate evolutionary trajectories for hundreds of millions of years. Although recent work understandably has emphasized the commonalities of innate defenses, there is also ample evidence, as from completed genome studies, to suggest that even members of the same invertebrate order have taken significantly different approaches to internal defense. These data suggest that novel immune capabilities will be found among the different phyla. Many invertebrates have intimate associations with symbionts that may play more of a role in internal defense than generally appreciated. Some invertebrates that are either long lived or have colonial body plans may diversify components of their defense systems via somatic mutation. Somatic diversification following pathogen exposure, as seen in plants, has been investigated little in invertebrates. Recent molecular studies of sponges, cnidarians, shrimp, mollusks, sea urchins, tunicates, and lancelets have found surprisingly diversified immune molecules, and a model is presented that supports the adaptive value of diversified non-self recognition molecules in invertebrates. Interactions between invertebrates and viruses also remain poorly understood. As we are in the midst of alarming losses of coral reefs, increased pathogen challenge to invertebrate aquaculture, and rampant invertebrate-transmitted parasites of humans and domestic animals, we need a better understanding of invertebrate immunology.

Animals↗