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PubMedDate not supplied

Comparison of ongoing compound field potentials in the brains of invertebrates and vertebrates.

(1) Ongoing compound field potential fluctuations of higher brain centers (the micro-EEG of some authors) are considered as a biological phenomenon, a sign of the activity in the organized assemblage of cells. Such activity has been compared in several taxa with quite different brain structure to look for possible evolution in the form of the field potentials and for possible explanations of differences and similarities. (2) Recordings were made with semimicroelectrodes in the neuropile of the cerebral ganglion of the mollusc, Aplysia, with comparative observations on Helix, and the arthropods Limulus, Melanoplus, and Cambarus, and in or on the cerebral cortex and optic tectum of rays, cats and rabbits, with comparative observations on sharks, bony fish, turtles and geckos in unstimulated resting or generalized arousal states. Manipulations of state did not alter the main findings. (3) Power spectra in the cerebral ganglia of various higher invertebrates are similar; activity is fast and spikey (with the exception of Octopus). Integrated energy above 50 Hz exceeds that from 2-50 Hz and falls slowly with frequency; in Aplysia the power spectrum falls less than 10 dB between 10 and 300 Hz. In vertebrates from fish to mammals activity is similar in being mainly slow (less than 40 Hz); it commonly falls greater than 20 dB between 10 and 50 Hz. (4) Amplitude is low in invertebrates and lower vertebrates. RMS voltage in Aplysia (3-300 Hz, reference electrode remote) is typically less than 10 microV; in the ray optic tectum less than 25 microV (2-50 Hz); in the dorsal cortex of the gecko less than 30 microV, in the cat cortex greater than 85 microV. In the vertebrates amplitude does not change greatly with small shifts in electrode position, as it does in invertebrates. (5) Coherence decline with distance, measured tangentially at different electrode separations in the millimeter range, is used as an estimator of synchrony. Averaged coherence between loci 1 mm apart is negligible in Aplysia in any band from 3 to 100 Hz; in the ray tectum it is low, 0.25-0.5 between 3 and 16 Hz. In the turtle dorsal pallium it is higher, at 2 mm, 0.6-0.75 in this band. In the rabbit cortex coherence is even higher, typically greater than 0.7 at 1 mm, and greater than 0.3 at 4 mm in this band. (6) Band-pass filtered electrograms, ca. one octave wide, in all species show constant waxing and waning in each band; amplitude is not maintained even for a second. (ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMedDate not supplied

Distribution and immunochemical character of neurotensin-like material in representative vertebrates and invertebrates: apparent conservation of the COOH-terminal region during evolution.

Using a radioimmunoassay for bovine neurotensin (NT) and various region specific antisera which react selectively with different portions of the molecule, the presence of immunoreactive NT (iNT) in a wide range of vertebrate and invertebrate species has been demonstrated. While antisera directed towards the N-terminal region of NT recognized only mammalian forms of NT, antisera directed towards the C-terminal region of NT recognized materials from all species examined, including representatives of all vertebrates and invertebrate classes. When extracts of the brain and gut of the vertebrates examined were chromatographed on Sephadex G-25 multiple NT-like substances were observed, and the patterns of iNT obtained seemed to fall into three groups: (a) mammals, (b) birds and reptiles and (c) amphibians and fish. Extracts of invertebrates also exhibited multiple peaks of iNT on Sephadex G-25 and the profiles observed resembled those for lower vertebrates. Partially purified iNT obtained from chicken, turtle, dogfish and lobster was shown to increase hematocrit and induce cyanosis in anesthetized rats. These findings indicate (a) that NT-like substances appear to be present throughout the animal kingdom, (b) that the C-terminal region of NT is highly conserved while the N-terminal region varies, and (c) that in any one animal multiple substances sharing C-terminal homologies with NT exist. These findings are consistent with the notion that NT and related peptides participate in important processes basic to animal life and that their functioning depends highly upon elements located in their C-terminal regions. They further suggest the existence of an entire family of NT-related peptides in each animal form, possibly distributed differently and functioning differently in the various organs of the animal.

Amino Acid Sequence↗

PubMed1985

Cholecystokinin and its receptors in vertebrates and invertebrates.

Recent studies have indicated that cholecystokinin (CCK) peptides have a long evolutionary history. However, whereas all vertebrates examined have been shown to contain CCK-like peptides, this has not been possible to demonstrate for all invertebrate groups. Immunostaining studies indicate that CCK peptides originate only in neurons in groups below the level of the protochordates. It seems likely that CCK gastrointestinal endocrine cells evolved first at the level of the protochordates, possibly from sensory gut neurons similar to those seen in the invertebrates. Immunochemical and biological studies of a few invertebrate CCK-like peptides suggest that those molecules are substantially different in structure from vertebrate CCKs. Gastrin appears to have evolved from CCK at the level of the appearance of amniotes in vertebrate phylogeny. In mammals, central and peripheral CCK receptors differ in specificity for CCK- and gastrin-like peptides. Comparative studies reveal that this is true for birds as well, but reptiles, amphibia, and fish brain and pancreas CCK receptors exhibit nearly identical specificity patterns. This suggests that the lower vertebrate CCK receptor is ancestral to the distinct brain and pancreas CCK receptors seen in birds and mammals.

Animals↗

PubMed1988

Phylogenetic study of the oxytocin-like immunoreactive system in invertebrates.

1. A phylogenetic study of oxytocin (OXT)-like immunoreactive cells was performed by the PAP method in the central nervous system of invertebrates. 2. The immunoreactivity was detected in the nerve cells of Hydra magnipapillata of the Coelenterata; Neanthes japonica and Pheretima communissima of the Annelida; Oncidium verrucosum, Limax marginatus and Meretrix lamarckii of the Mollusca; and Baratha brassica of the Arthropoda. 3. No immunoreactive cells were found in Bipalium sp. of the Platyhelminthes; Pomacea canaliculata, Aplysia kurodai, Bradybaena similaris and Achatina fulica of the Mollusca; and Gnorimosphaeroma rayi, Procambarus clarkii, Hemigrapsus sanguineus, Helice tridens and Gryllus bimaculatus of the Arthropoda; Asterina pectinifera of the Echinodermata; and Halocynthia roretzi of the Protochordata. 4. These results demonstrate that an OXT-immunoreactive substance is widely present not only in vertebrates but also in invertebrates. 5. OXT seems to have been introduced into these invertebrates at an early stage of their phylogenetic history.

Animals↗

PubMed1988

Phylogenetic study of the arginine-vasotocin/arginine-vasopressin-like immunoreactive system in invertebrates.

1. A phylogenetic study of arg-vasotocin (AVT)/arg-vasopressin (AVP)-like immunoreactive cells was performed by the PAP method in the central nervous system of invertebrates. 2. The immunoreactivity was detected in the nerve cells of Hydra magnipapillata of the Coelenterata; Neanthes japonica and Pheretima communissima of the Annelida; Pomacea canaliculata, Aplysia kurodai, Oncidium verrucosum, Bradybaena similaris, Achatina fulica, Limax marginatus and Meretrix lamarckii of the Mollusca; Gnorimosphaeroma rayi, Hemigrapsus sanguineus, Gryllus bimaculatus and Baratha brassicae of the Arthropoda; Asterina pectinifera of the Echinodermata; and Halocynthia roretzi of the Protochordata. 3. No immunoreactivity was detected in Bipalium sp. of the Platyhelminthes, or in Procambarus clarkii and Helice tridens of the Arthropoda. 4. From these results, it appears that AVT/AVP is a phylogenetically ancient peptide which is present in a wide variety of invertebrates. 5. The actions of AVT/AVP and its presence in invertebrates are discussed.

Animals↗

PubMed1992

Presynaptic modulation of sensory afferents in the invertebrate and vertebrate nervous system.

1. Ultrastructural examination of the central terminals of sensory afferent neurons in both invertebrates and vertebrates demonstrates that the synapses that form the substrate for presynaptic inhibition and facilitation are almost universally present. 2. Presynaptic modulation of afferent input acts in many ways which tailor the inflow of sensory information to the behaviour of the animal, effectively providing a means of turning this on and off, or of combining information of the same or different modalities to refine responsiveness or clarify ambiguity. 3. Presynaptic modulation may act in several different roles on the same afferent. 4. A comparison of the mechanisms of presynaptic inhibition in different animals demonstrates the likelihood of a variety of common mechanisms, several of which may act simultaneously on the same terminal. These include changes in the conductance of the afferent membrane to Cl-, K+ and Ca2+ ions, in addition to less well understood mechanisms that directly affect transmitter release. 5. A single transmitter can produce several effects on a terminal through the same or different receptors. 6. Ultrastructural studies of afferent terminals reveal that only a proportion of boutons on a given afferent may receive presynaptic input and that this may depend on the region of the nervous system in which these are found or on the identity of the postsynaptic neurons contacted. 7. The synaptic relationships of afferent terminals can be complex. In invertebrates different types of presynaptic neuron may interact synaptically, as may postsynaptic dendrites in vertebrates. 8. Axons presynaptic to afferent terminals in vertebrates frequently synapse also with dendrites postsynaptic to the afferents. 9. In both invertebrates and vertebrates reciprocal interactions between afferents and postsynaptic neurons are seen. 10. Ultrastructural immunocytochemistry reveals the likely dominance of GABA as an agent of presynaptic inhibition but also demonstrates the possible presence of other transmitters some of whose roles are less completely understood.

Animals↗

PubMed1988

Aspartic proteinases in fishes and aquatic invertebrates.

1. The literature on molecular properties and physiological role of aspartic proteinases in fishes and aquatic invertebrates has been reviewed. 2. Pepsins have not been detected in invertebrates, and apparently cathepsin D, as well as other cathepsins, act both as digestive and lysosomal enzymes in many of these animals. The molecular properties of invertebrate cathepsin D correspond with cathepsin D in fishes and mammalians. 3. Fishes with a true stomach have pepsinogen secretion. Fish pepsins have higher pH optimum and are less stable in strong acid conditions than mammalian pepsins. They are very efficient at low temperatures, but less thermostable than mammalian pepsins. 4. Many fishes have two significantly different pepsins: Pepsin I and Pepsin II, which digest haemoglobin at a maximal rate in the pH ranges 3-4 and 2-3 respectively. Usually the pI of Pepsin I is in the range 6.5-7, whereas pI of Pepsin II is about 4. 5. Fish Pepsin I and cathepsin D have very similar molecular properties, and a hypothesis proposing that cathepsin D is the ancestor enzyme of aspartic proteinases in higher animals is presented.

Animals↗

PubMed1990

Homologies between the amino acid sequences of some vertebrate peptide hormones and peptides isolated from invertebrate sources.

1. The 4K-prothoracicotropic hormone (PTTH) or bombyxin and the melanization-reddish coloration hormone of the silkworm Bombyx mori resemble insulin and insulin-like growth factors. 2. The family of adipokinetic/red pigment concentrating hormones has some similarity with glucagon. 3. Members of the FMRFamide family are found in vertebrates as well as in invertebrates. 4. In Locusta, a molecule immunologically and biologically related to amphibian melanophore stimulating hormone has been partially characterized. 5. Enkephalins and enkephalin-related peptides occur in insects and other invertebrates. 6. Peptides belonging to the tachykinin family have been isolated from molluscan (Octopus) salivary glands and from insect nervous tissue (Locusta migratoria). 7. Invertebrate arginine-vasotocin homologs have been isolated from an insect (Locusta migratoria) and from a mollusc (Conus). 8. In Leucophaea, Locusta and Drosophila, peptides resembling those of the vertebrate gastrin/cholecystokinin family have been identified. 9. As the number of different neuro-/gut peptides with possible function(s) as hormone, neurotransmitter or neuromodulator is now estimated to be of the order of a few hundred, more similarities will probably show up in the near future.

Amino Acid Sequence↗

PubMed1992

Retinal photoisomerase: role in invertebrate visual cells.

In invertebrate visual cells, the rhodopsin content is maintained at a high level by the fast process of photoregeneration during daylight. Rhodopsin is converted by photoabsorption to metarhodopsin, which is reconverted to rhodopsin by light. In addition, rhodopsin is regenerated by a slow process of renewal which takes days to complete and involves the biosynthesis of opsin. It is well known that rhodopsin can be formed from opsin only when 11-cis-retinal is present; this requires the existence of an isomerizing enzyme which is capable of transforming all-trans-retinal, released from the degradation of metarhodopsin, into the 11-cis-retinal isomer. In some invertebrate visual systems, experiments on rhodopsin regeneration have been interpreted by assuming that the isomerization reaction is a light-dependent process involving a retinal-protein complex. Two retinal photoisomerases which have been well characterized, i.e. bee photoisomerase and cephalopod retinochrome, are reviewed here. Their properties are compared in order to determine their physiological role, which is likely to be in the renewal of visual pigment rhodopsin. To conclude, a visual pigment cycle is proposed in which rhodopsin regeneration follows two light-dependent pathways. This greatly simplifies the rhodopsin regeneration scheme for invertebrate visual systems.

Animals↗

PubMed2005

Metallothioneins in aquatic invertebrates: their role in metal detoxification and their use as biomarkers.

The literature on metallothioneins (MT) and metallothionein-like proteins (MTLP) in aquatic invertebrates is large and increasing, and yet inconsistencies and confusion remain, not least over the physiological role of MT and their use as biomarkers in environmental monitoring programmes. We have collated published information on MT in three important groups of aquatic invertebrates-the molluscs, crustaceans and annelid worms, and attempted to seek explanations for some of the apparent inconsistencies present in the dataset. MTs can be induced by the essential metals Cu and Zn and the non-essential metals Cd, Ag and Hg in both vertebrates and invertebrates, but their induction is variable. Such variation is intraspecific and interspecific, and is down to a variety of reasons environmental and physiological explored here. Against this background of variability MTs do appear to play roles both in the routine metabolic handling of essential Cu and Zn, but also in the detoxification of excess amounts intracellularly of these metals and of non-essential Cd, Ag and Hg. Different isoforms of MT probably play different physiological roles, and the dependence on MT in detoxification processes varies environmentally and between zoological groups. MTs can be used as biomarkers if used wisely in well-designed environmental monitoring programmes.

Animal Structures↗

PubMed2006

Comparison of seasonal dynamics of the essential PUFA contents in benthic invertebrates and grayling Thymallus arcticus in the Yenisei river.

Seasonal dynamics of contents of essential polyunsaturated fatty acids (PUFA) in dominant groups of benthic invertebrates: gammarids (Gammaridae, Amphipoda), oligochaetes (Oligochaeta), chironomid larvae (Chironomidae, Diptera) and caddisfly larvae (Trichoptera), and dominant benthivorous fish, Siberian grayling Thymallus arcticus, have been studied in ecosystem of the large Siberian river. During the year of the study most benthic invertebrate taxa showed significant variations in the contents of both C-18 and long chain C-20-22 PUFAs. In contrast, the fish, which consumed the zoobenthos, had no significant seasonal variations in long chain PUFAs' contents. Thereby, the fish, as organisms of relatively higher evolution level than invertebrates, was supposed to have more strict metabolic control of long chain PUFAs' contents. Evidence was obtained that the studied fish species, grayling, may be capable to convert dietary EPA into DHA.

Animals↗

PubMed2005

Uselessness and indirect negative effects of an insecticide on rice field invertebrates.

Macro-invertebrate assemblages on organic and conventional rice fields were quantitatively compared in the Camargue (Rhone delta, France). There was no major difference in family richness, but significant differences as regard to abundance. Fipronil, the insecticide used to control chironomid larvae, was one of the main factors explaining those differences. Its negative impact on predatory invertebrates appears to explain the paradoxical lack of difference in chironomid abundance between organic and conventional fields, observed during the study. Macro-invertebrate biomass estimation showed that, for some birds such as herons, conventional rice fields offered a lower value as foraging habitats than organic ones.

Agriculture↗

PubMed2004

Invertebrate care.

Invertebrates are attracting increasing interest within the veterinary profession. They are also significant in their own right; as the Council of Europe's "Charter on Invertebrates" points out, they are the most important component of wild fauna as well as providing food, contributing to agriculture and forestry, and aiding medicine,industry, and crafts. Whenever invertebrates are kept in captivity they should be subject to high standards of management and care and veterinary attention-whether by the veterinarian or by the veterinary technician-should be based on sound biological and humanitarian principles.

Animal Husbandry↗

PubMed2004

Definitions of pathogenicity and virulence in invertebrate pathology.

Accurate definition and usage of terminology are critical to effective communication in science. In a recently published article, the clarity and consistency of the terms pathogenicity and virulence as used in invertebrate pathology were called into question, and a revision of these terms was proposed. Our objective was to examine definitions of pathogenicity and virulence and their use in invertebrate pathology, and respond to this article. Although usage of the terms pathogenicity and virulence varies, we found considerable consistency in the published definitions of these terms in the invertebrate pathology literature throughout the history of the discipline, as well as among related disciplines such as medicine and microbiology. We did not find the established definitions to be lacking in clarity or utility. Therefore, we recommend that the definition and use of these terms adhere to precedence. Specifically, pathogenicity is the quality or state of being pathogenic, the potential ability to produce disease, whereas virulence is the disease producing power of an organism, the degree of pathogenicity within a group or species. Pathogenicity is a qualitative term, an "all-or-none" concept, whereas virulence is a term that quantifies pathogenicity.

Animals↗

PubMed2004

Identification of a new antizyme mRNA +1 frameshifting stimulatory pseudoknot in a subset of diverse invertebrates and its apparent absence in intermediate species.

The expression of eukaryotic antizyme genes requires +1 translational frameshifting. The frameshift in decoding most vertebrate antizyme mRNAs is stimulated by an RNA pseudoknot 3' of the frameshift site. Although the frameshifting event itself is conserved in a wide variety of organisms from yeast to mammals, until recently no corresponding 3' RNA pseudoknot was known in invertebrate antizyme mRNAs. A pseudoknot, different in structure and origin from its vertebrate counterparts, is now shown to be encoded by the antizyme genes of distantly related invertebrates. Identification of the 3' frameshifting stimulator in intermediate species or other invertebrates remains unresolved.

Animals↗

PubMed2006

Nitric oxide: an antiparasitic molecule of invertebrates.

Since Furchgott, Ignarro and Murad won the Nobel prize in 1998 for their work on the role of nitric oxide (NO) as a signaling molecule, many reports have shown the seemingly limitless range of body functions controlled by this compound. In vertebrates, the role of NO as a defense against infection caused by viruses, bacteria, and protozoan and metazoan parasites has been known for several years. New evidence, however, shows that NO is also important in defending invertebrates against parasites. This discovery is a breakthrough in the understanding of how the invertebrate immune system works, and it has implications for the emerging field of invertebrate ecological immunology.

Animals↗

PubMed2005

From chemical structure to environmental biosynthetic pathways: navigating marine invertebrate-bacteria associations.

Many natural products from marine invertebrates are promising drugs or drug leads but the problem of supply has delayed the development of these agents. Bacteria living in complex associations with animals are often proposed to be the real producers of "invertebrate" metabolites. Recent advances in biosynthetic pathway discovery from these symbiotic bacteria herald a new era in which biosynthetic genes will be cloned rapidly to provide promising molecules from marine invertebrates.

Animals↗

PubMed2002

Comparison of benthic invertebrate assemblages at Spartina alterniflora marshes reestablished after an oil spill and existing marshes in the Arthur Kill (NY/NJ).

In January 1990, an oil spill damaged salt marshes along the banks of the Arthur Kill (New York and New Jersey, USA). In the years following the spill, Spartina alterniflora seedlings were planted at a number of the oil damaged sites and successfully reestablished at these sites. In 1996, the National Marine Fisheries Service began a study to compare the benthic invertebrate assemblages at the reestablished S. alterniflora marshes to those at nearby existing marshes in the Arthur Kill. Oligochaetes, nematodes, and the small tube-building polychaete, Manayunkia aestuarina were the dominant taxa in the study. Significant differences were found in the abundances of all invertebrate individuals, oligochaetes, and nematodes between the September and May sampling times but not between reestablished and existing marshes. Although benthic invertebrate community structure was similar at reestablished and existing marshes three to four years after planting, the functional similarity of these marshes was not assessed in this study.

Accidents↗