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PubMed1998

Towards understanding the role of insulin in the brain: lessons from insulin-related signaling systems in the invertebrate brain.

Insulin is a molecule that has played a key role in several of the most important landmarks in medical and biological research. It is one of the most extensively studied protein hormones, and its structure and function have been elucidated in many vertebrate species, ranging from man to hagfish and turkey. The structure, function as well as tissue of synthesis of vertebrate insulins are strictly conserved. The structural identification of insulin-related peptides from invertebrates has disrupted the picture of an evolutionary stable peptide hormone. Insulin-related peptides in molluscs and insects turned out to be a structurally diverse group encoded by large multi-gene families that are uniquely expressed in the brain and serve functions different from vertebrate insulin. In this review, we discuss invertebrate insulins in detail. We examine how these peptides relate to the model role that vertebrate insulin has played over the years; however, more importantly, we discuss several unique principles that can be learned from them. We show how diversity of these peptides is generated at the genetic level and how the structural diversity of the peptides is linked to the exclusive presence of a single type of neuronal insulin receptor-related receptor. We also discuss the fact that the invertebrate peptides, in addition to a hormonal role, may also act in a synaptic and/or nonsynaptic fashion as transmitters/neuromodulators on neurons in the brain. It can be expected that the use of well-defined neuronal preparations in invertebrates may lead to a further understanding of these novel functions and may act as guide preparations for a possible role of insulin and its relatives in the vertebrate brain.

Amino Acid Sequence↗

PubMedDate not supplied

Functional multimodality of axonal tree in invertebrate neurons.

This review, based on invertebrate neuron examples, aims at highlighting the functional consequences of axonal tree organization. The axonal organization of invertebrate neurons is very complex both morphologically and physiologically. The first part shows how the transfer of information along sensory axons is modified by presynaptic inhibition mechanisms. In primary afferents, presynaptic inhibition is involved in: 1) increasing the dynamic range of the sensory response; 2) processing the sensory information such as increasing spatial and/or temporal selectivity; 3) discriminating environmental information from sensory activities generated by the animal's own movement; and 4) modulating the gain of negative feedback (resistance reflex) during active rhythmic movements such as locomotion. In a second part, the whole organization of other types of neurons is considered, and evidence is given that a neuron may not work as a unit, but rather as a mosaic of disconnected 'integrate-and-fire' units. Examples of invertebrate neurons are presented in which several spike initiating zones exist, such as in some stomatogastric neurons. The separation of a neuron into two functionally distinct entities may be almost total with distinct arborizations existing in different ganglia. However, this functional separation is not definitive and depends on the state of the neuron. In conclusion, the classical integrate-and-fire representation of the neuron, with its dendritic arborization, its spike initiating zone, its axon and axonal tree seems to be no more applicable to invertebrate neurons. A better knowledge of the function of vertebrate neurons would probably demonstrate that it is the case for a large number of them, as suggested by the complex architecture of some reticular interneurons in vertebrates.

Animals↗

PubMed2000

UV effects on invertebrate and diatom assemblages of Greece.

The effects of solar radiation (PAR, UVA, UVB) on the productivity and structure of diatom and invertebrate assemblages were assessed during primary succession on artificial substrate near a rocky shore of the Saronikos Gulf, Greece. Three light treatments were performed (PAR, PAR+UVA, and PAR+UVA+UVB) at 0.5, 1.0 and 1.5 m of depth. Pennate diatoms were the major component of the developing periphytic communities during the study period. Exposure to solar UVB initially reduced the biomass and altered the structure of the diatom assemblages. The highest biomass of diatom assemblages was observed under PAR (49.2 g/m2). This value was significantly higher than the biomass of assemblages growing under PAR+UVA+UVB, but not significantly different compared to the biomass of assemblages exposed to PAR+UVA. These differences, however, did not persist at later stages. The most abundant invertebrate groups present were Polychaetes and Crustaceans. Solar UVB did not have significant effects on invertebrate biomass. Analysis of the invertebrate assemblage structure revealed time-course differences but no clear trends among the different treatments.

Animals↗

PubMed2001

Integumental disease in invertebrates.

The necessarily truncated discussion of integumental neoplasia in invertebrates, given the lack of investigation of such lesions involving individual animals, shows how invertebrate veterinary medicine has a long way to go before reaching the levels of diagnosis and therapeutics of vertebrate exotic species. Nevertheless, the importance of a disease such as varoosis in a species such as the honey bee, which has a massive influence through pollination quite beyond its relevance as a honey producer, shows the importance of never excluding invertebrates from discussion of disease in exotic species. It is therefore commendable that this issue of the Veterinary Clinics of North America: Exotic Animal Practice seeks wherever possible to include invertebrates in its discussion.

Animals↗

PubMed2003

Aquaculture of three phyla of marine invertebrates to yield bioactive metabolites: process developments and economics.

Large-scale, renewable supplies of chemical constituents derived from marine invertebrates have limited development of potential new natural product drugs. This paper describes the development of two in-sea aquaculture systems designed and engineered for production of large quantities of biomass for two species of marine invertebrates desired for their natural product chemical constituents. The two invertebrates and their products were: (1) the cosmopolitan, arborescent bryozoan Bugula neritina (Phylum Bryozoa) for its anticancer chemical constituent bryostatin 1; and (2) Ecteinascidia turbinate (Phylum Tunicata) the source of anticancer ecteinascidin 743. For the third invertebrate Phylum Porifera, and its representative sponge Acanthella cavernosa (desired for its anti-parasitic and anti-infective kalihinols) in-sea systems were not developed in favor of controlled environment tank aquaculture systems. For the bryozoan and tunicate, projected economics for commercial-scale in-sea production proved cost effective. This was in contrast to the controlled environment sponge culture tank system, which did not prove to be economical due to inherent slow growth and low natural product yields of the sponge in culture. A non-destructive method for "milking" natural product chemicals from sponges was tested and is described.

Animals↗

PubMed2000

The importance of leaf- and litter-feeding invertebrates as sources of animal protein for the Amazonian Amerindians.

At least 32 Amerindian groups in the Amazon basin use terrestrial invertebrates as food. Leaf- and litter-consuming invertebrates provide the more important, underestimated food sources for many Amerindian groups. Further, litter-consuming earthworms are also an important food resource for the Ye'Kuana (also known as Makiritare) in the Alto Orinoco (Amazonas, Venezuela). By selecting these small invertebrates the Amerindians are choosing their animal food from those food webs in the rainforest which have the highest energy flow and which constitute the greatest renewable stock of readily available nutrients. Here we show that the consumption of leaf- and litter-feeding invertebrates as a means of recovering protein, fat and vitamins by the forest-living peoples offers a new perspective for the development of sustainable animal food production within the paradigm of biodiversity maintenance.

Animals↗

PubMed2006

Bacillus species in the intestine of termites and other soil invertebrates.

Soil invertebrates harbour a complex microbial community in their intestinal system. The total number of microbes in the hindgut of soil invertebrates can reach a titre of 10(11) ml(-1). The gut microbes play an indispensable role in the digestion of food and are of ecological importance in the global carbon cycle. The gut microbiota can include a variety of micro-organisms from the three domains Bacteria, Archaea and Eucarya. The bacterial groups from the intestinal systems are mainly affiliated to the proteobacteria, the gram-positive groups Firmicutes and Actinobacteria, the Bacteroides/Flavobacterium branch and the spirochetes. The Archaea are represented by methanogens. The eukaryotic groups consist of protozoa, yeasts and fungi. Intestinal bacteria are involved in the degradation of cellulose, hemicellulose and aromatic compounds as well as nitrogen fixation. They also contribute to the redox status of the gut. Bacilli form a significant portion of the intestinal microbial community of soil invertebrates, especially among cellulose degraders. The diversity and function of bacilli in soil invertebrates will be discussed in this paper.

Animals↗

PubMed1992

Invertebrate immunity: another viewpoint.

All vertebrates and invertebrates manifest self/non-self recognition. Any attempt to answer the question of adaptive significance of recognition must take into account the universality of receptor-mediated responses. These may take two forms: (1) rearranging, clonally distributed antigen-specific receptors that distinguish in the broadest sense between self and non-self, and non-self A from non-self B, latecomers on the evolutionary scene; (2) pattern recognition receptors, the earliest to evolve and still around, necessitating the requirement for induced second signals in T- and B-cell activation. Either strategy need not force upon invertebrates the organization, structure and adaptive functions of vertebrate immune systems. Thus, we can freely delve into the unique aspects of the primitive immune mechanisms of invertebrates. In contrast, using the opposite strategy which is still problematic, i.e. linking invertebrate and vertebrate defence, seems to give us an approach to universality that might eventually reveal homologous kinship.

Animals↗

PubMed1978

Invertebrate collagens.

The collagens of all major invertebrate phyla have been studied, but characterization has been thorough in only a few classes and in no case in the detail (such as sequence analysis) known for vertebrate collagen. Biochemical data on insect collagen are particularly sparse. Invertebrate and vertebrate collagens are strikingly similar, with some notably unique features in annelids and nematodes. Present data do not support the suggestion that invertebrate collagens resemble vertebrate basement membrane collagen. In invertebrates, as in vertebrates, collagens of specific tissues show differenes that probably reflect individual tissue requirements.

Amino Acid Sequence↗

PubMed1991

Use of invertebrate animals to teach physiological principles.

Experiments with invertebrate animals offer valuable opportunities in the teaching of physiology. In some cases, exercises that use these animals may demonstrate physiological principles more clearly than experiments that use vertebrates. Other experiments are easy to perform because of the latitude of conditions in which the tissues of many invertebrates function. Experiments with invertebrates can also illustrate a far wider range of physiological mechanisms than occurs in vertebrates and are especially suited for opportunities for independent original investigation by the students. Since at this time invertebrates are underutilized in teaching, much can be gained by the design, testing, and dissemination of innovative experimental protocols for student use.

Animal Welfare↗

PubMed2003

Liming of River Audna, Southern Norway: a large-scale experiment of benthic invertebrate recovery.

This study describes the recovery of sensitive invertebrates after liming of the anadromous part of River Audna in 1985. The river lost its salmon population during 1960-1970. The aim of the liming was to produce a water quality with pH > 6.0 and ANC > 20 microg L(-1) and to reduce the content of labile aluminum. Highly sensitive invertebrates like the mayfly Baetis rhodani were not found in the river before liming. Two years after liming, several sensitive invertebrate species showed a positive response. B. rhodani was then recorded at 2 sites in the lower part of the river. In the following 5 years several species of sensitive invertebrates recolonized the whole limed reach of the river and became numerous. Ten years after liming the snail Lymnaea peregra was recorded in the river. The dispersa of this species was also very fast and after 5 years it was found at all investigated sites in the limed main river covering a reach of 40 km. Reduced sulfur deposition in the area also resulted in water-quality improvements in th unlimed stretches of River Audna. Comparisons between limed and unlimed localities indicated that the water quality and the critical limits of sensitive species are the ma factors determining the fauna composition in River Audna independent of the reason for the change in water quality.

Acid Rain↗

PubMed2003

Insight into tachykinin-related peptides, their receptors, and invertebrate tachykinins: a review.

Tachykinins (TKs) constitute the largest vertebrate neuropeptide family with multifunctions in central and peripheral tissues. In several invertebrate species, two types of structurally related peptides, 'tachykinin-related peptides (TKRPs)' and 'invertebrate tachykinins (inv-TKs)' have been identified. TKRPs, isolated from the nerve and/or gut tissues, contain the common C-terminal sequence -Phe-X-Gly-Y-Arg-NH(2) (X and Y are variable) analogous to the vertebrate TK consensus -Phe-X-Gly-Leu-Met-NH(2), and exhibit vertebrate TK-like contractile activity on invertebrate gut tissues. Inv-TKs have been shown to be present exclusively in the salivary gland of several species, to share vertebrate TK consensus motif, and to possess TK-like potencies on vertebrate, not invertebrate tissues. However, the functional and evolutionary relevance of TKRPs and inv-TKs to vertebrate TKs remains to be understood. Recent studies have revealed that TKRP precursors dramatically differ from vertebrate preprotachykinins in structural organization and that TKRP receptors share structural and functional properties with vertebrate TK receptors. Moreover, the C-terminal arginine in TKRPs has been shown to play an essential role in discriminating their receptors from vertebrate TK receptors. Such recent marked progress is expected to enhance further investigation of biological roles of TKRPs. This review provides an overview of the basic findings obtained previously and a buildup of new knowledge regarding TKRPs and inv-TKs. We also compare TKRPs and inv-TKs to vertebrate TKs with regard to evolutionary relationships in structure and function among these structurally related peptides.

Amino Acid Sequence↗

PubMedDate not supplied

Regulation of synaptic function by neurotrophic factors in vertebrates and invertebrates: implications for development and learning.

Recent studies have demonstrated that neurotrophic factors contribute to the molecular events involved in synaptic plasticity, both during vertebrate development and in the mature nervous system. Although it is well established that many of the cellular and molecular mechanisms underlying synaptic plasticity are conserved between invertebrates and vertebrates, there are, as yet, very few neurotrophic factors identified in invertebrate species. Nonetheless, vertebrate neurotrophins can influence invertebrate neuronal growth and plasticity. In addition, homologs of neurotrophic factor receptors have been identified in several invertebrate species. These studies may indicate that the roles of neurotrophins in both developmental and adult plasticity are highly conserved across diverse phyla.

Animals↗

PubMed2002

Time of submergence using aquatic invertebrate succession and decompositional changes.

Pig carcasses were placed in pond and stream habitats in the Malcolm Knapp Research Forest in Maple Ridge, B.C. for approximately one year, to examine the development, species, and sequence of invertebrates associated with the carrion. An invertebrate successional database was created for pond and stream habitats for potential use in estimating time of submergence in water related death investigations. Analysis has shown that a predictable succession of invertebrates colonize the carrion. However, whether or not this succession is carrion dependent or seasonal is unknown. There is a difference in the species composition between pond and stream habitats. Habitats influence invertebrate fauna, therefore, species colonizing carrion are habitat-specific. In both habitats, no one organism can determine time of submergence alone. Decompositional descriptions from this research were compared with 15 freshwater related death investigations. Similarities were seen in the earlier decompositional characteristics including bloat, discoloration, and nail shedding; however, the human descriptions were so vague that they had little value in determining time of submergence and hence time of death.

Animals↗

PubMed1996

Ultrastructure of invertebrate muscle cell types.

The muscular cells of invertebrates can be divided into three major classes on the basis of their striation pattern: transversely striated, obliquely striated, or smooth muscle. Transversely striated muscles have either continuous or discontinuous Z lines and, thus, can be subdivided into two types respectively. Of all invertebrate muscles, the transversely striated muscle with continuous Z lines is the most similar to the vertebrate skeletal muscle and is present in arthropods, whose musculature (including the visceral muscles) only consists of this cell type. These muscles are multinucleate cells that contain myofibrils showing well-defined sarcomeres. Transversely striated muscles with discontinuous Z lines, consisting of multiple small electrondense patches, are found in the translucent portions of adductor muscles of some bivalves and in the heart muscle of the gastropods. This muscle is formed by mononucleated cells with centrally-located nuclei and a single myofibril. The obliquely striated muscle appears in nematodes, annelids, molluscs, brachiopods and chaetognathes and consists of mononucleated cells with both thick and thin myofilaments which form sarcomeres delimited by Z lines. Myofilaments are not perpendicular but oblique to the Z lines, so that both A and I bands may be seen together in each of the three spatial planes of view. Smooth muscle has been reported in coelenterates, annelids, molluscs, brachiopods and echinoderms, but is lacking in arthropods. These muscle cells have a centrally-located nucleus and abundant thin and thick myofilaments without apparent sarcomeres. The most relevant characteristics of invertebrate muscle cells are the following. The thick (myosin) myofilaments show a variable length (from 2.2 microns up to 6 microns) and width (from 14 nm up to 231 nm) and contain a central core of paramyosin, which is absent in vertebrate muscles. Thick filaments are homogenous in transversely striated muscles and either homogeneous or fusiform in the obliquely striated and smooth muscles. Thin filaments measure 6 nm in diameter. They contain tropomyosin and, only in striated muscles, also troponin. The thin/thick filament ratio varies from 3/1 to 6/1, even in smooth muscles. The plaques for filament anchorage (Z lines in striated muscles or electrondense bodies in smooth muscles) contain alpha-actinin. The striated (transversely or obliquely) muscles show long sarcomeres (up to 9 microns) and the number of thin filaments around each thick filament varies from 3 to 12, so that each thin filament is shared by two thick filaments. Z lines in the striated muscles show a variety of structures that differ from one species to another (filament bundles in nematodes, bars in annelids, small patches in molluscs, etc). Many striated muscles contain titin (connectin) and intermediate filaments and display a sarcotubular system consisting of T tubules and sarcoplasmic reticulum tubules. Both structures form dyads and, more rarely, triads. The location of T tubules as well as the configuration and distribution of sarcoplasmic reticulum vary among muscles and species. Invertebrate smooth muscle differs from that of vertebrates principally in the higher proportion and larger diameter of thick myofilaments. These may be fusiform and their size and number may vary widely among cells. These muscle cells may be classified by the characteristics of both the thick filaments and the electrondense bodies for filament anchorage.

Animals↗

PubMed1989

Cytoplasmic intermediate filament proteins of invertebrates are closer to nuclear lamins than are vertebrate intermediate filament proteins; sequence characterization of two muscle proteins of a nematode.

The giant body muscle cells of the nematode Ascaris lumbricoides show a complex three dimensional array of intermediate filaments (IFs). They contain two proteins, A (71 kd) and B (63 kd), which we now show are able to form homopolymeric filaments in vitro. The complete amino acid sequence of B and 80% of A have been determined. A and B are two homologous proteins with a 55% sequence identity over the rod and tail domains. Sequence comparisons with the only other invertebrate IF protein currently known (Helix pomatia) and with vertebrate IF proteins show that along the coiled-coil rod domain, sequence principles rather than actual sequences are conserved in evolution. Noticeable exceptions are the consensus sequences at the ends of the rod, which probably play a direct role in IF assembly. Like the Helix IF protein the nematode proteins have six extra heptads in the coil 1b segment. These are characteristic of nuclear lamins from vertebrates and invertebrates and are not found in vertebrate IF proteins. Unexpectedly the enhanced homology between lamins and invertebrate IF proteins continues in the tail domains, which in vertebrate IF proteins totally diverge. The sequence alignment necessitates the introduction of a 15 residue deletion in the tail domain of all three invertebrate IF proteins. Its location coincides with the position of the karyophilic signal sequence, which dictates nuclear entry of the lamins. The results provide the first molecular support for the speculation that nuclear lamins and cytoplasmic IF proteins arose in eukaryotic evolution from a common lamin-like predecessor.

Amino Acid Sequence↗

PubMed1992

Alkaline phosphatase and peptidase levels in invertebrate cartilage.

Cartilage is encountered in the skeletons of many advanced invertebrates, yet it never calcifies or is replaced by bone. In an attempt to account for the absence of bone in invertebrates, we tested a hypothesis proposing that absence or inadequate quantities of several enzymes associated with vertebrate osteogenesis may underlie the failure of the invertebrates to evolve bone. The enzymes examined were alkaline phosphatase, alanyl beta-naphthylamidase, and neutral protease. Their activities were measured in the gill cartilage of the Atlantic horseshoe crab, Limulus polyphemus, and the odontophore cartilage of the marine whelk, Busycon canaliculatum. Animals were collected from the Cape Cod area. Samples of cartilage of Limulus perichondrium, various non-skeletal tissues, and neonatal rat calvaria, the latter as a reference standard, were homogenized in 0.1 M phosphate buffer (pH 7.1) and analyzed for protein content and the above-mentioned enzyme activities. Alkaline phosphatase specific activity was readily detected in most tissues except the invertebrate cartilage specimens in which it was present only at near-trace levels. Naphthylamidase and protease activities were present in all tissues. In a single experiment, higher phosphatase values were recorded for Limulus cartilage retaining perichondrium, but in a subsequent trial assaying cartilage retaining perichondrium, denuded cartilage, and isolated perichondrium separately, it was demonstrated that phosphatase activity resided primarily within the perichondrium. Exposure of thick cryostat sections to p-nitrophenyl phosphate confirmed the suspicion that alkaline phosphatase activity was present principally in the perichondrium.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗

PubMed1989

Comparative study of invertebrate actins: antigenic cross-reactivity versus sequence variability.

The immunological similarities or differences between various actins from muscles of invertebrates were investigated. We elicited antibodies to actin purified from the adductor muscle of the mollusc, Pecten maximus. The antiserum comprised a major population that was specific for the N-terminal extremity of this isoform. This antibody population was used together with other antibodies specific for various domains on the surface of skeletal muscle actin to compare seven actins from invertebrate muscles. The N-terminal extremity showed close homologies between invertebrates (except for Crustacea) but differences were observed with vertebrate skeletal and cytoplasmic actins. In contrast, sequence 18-28, which constitutes part of the myosin interaction domain, appears to be conserved in all actins studied. Other regions (sequences 40-113, 168-226 and 285-375) presented a variable behaviour depending on the particular invertebrate species.

Actins↗