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At least 703 records · Page 39Linked to original sources
PubMed2005

Can sodium hypochlorite reduce the risk of species introductions from diapausing invertebrate eggs in non-ballasted ships?

Many transoceanic vessels enter the Great Lakes carrying residual ballast water and sediment that harbours live animals and diapausing eggs. In this study, we examine the potential for sodium hypochlorite (NaOCl) to reduce the risk of species introductions from diapausing invertebrate eggs in residual ballast sediment. We collected sediment from three transoceanic vessels and from Lake Erie and exposed them to NaOCl concentrations between 0 and 10,000 mg/L for 24 h. Hatching success was reduced by >89% in all four experiments at 1,000 mg/L relative to unexposed controls. Fewer species hatched at high than at low NaOCl concentrations. Based on an average residual ballast of 46.8 tonnes, the volume of NaOCl required to treat inbound vessels is 374 L. Impacts of NaOCl use could be minimized by neutralization of treated residuals with sodium bisulfite. Further research is needed, however, to evaluate the effect of NaOCl on ballast tank corrosion.

Animals↗
PubMed2024

Vertebrate and invertebrate animal infection models of Candida auris pathogenicity.

Candida auris is an emerging fungal pathogen with several concerning qualities. First recognized in 2009, it has arisen in multiple geographically distinct genomic clades nearly simultaneously. C. auris strains are typically multidrug resistant and colonize the skin much better than most other pathogenic fungi; it also persists on abiotic surfaces, enabling outbreaks due to transmission in health care facilities. All these suggest a biology substantially different from the 'model' fungal pathogen, Candida albicans and support intensive investigation of C. auris biology directly. To uncover novel virulence mechanisms in this species requires the development of appropriate animal infection models. Various studies using mice, the definitive model, are inconsistent due to differences in mouse and fungal strains, immunosuppressive regimes, doses, and outcome metrics. At the same time, developing models of skin colonization present a route to new insights into an aspect of fungal pathogenesis that has not been well studied in other species. We also discuss the growing use of nonmammalian model systems, including both vertebrates and invertebrates, such as zebrafish, C. elegans, Drosophila, and Galleria mellonella, that have been productively employed in virulence studies with other fungal species. This review will discuss progress in developing appropriate animal models, outline current challenges, and highlight opportunities in demystifying this curious species.

Animals↗
PubMed2003

Insect allatotropins belong to a family of structurally-related myoactive peptides present in several invertebrate phyla.

Originally named for its ability to stimulate juvenile hormone production by lepidopteran corpora allata, allatotropin has emerged as a neuropeptide with multiple neural, endocrine and myoactive roles. This paper describes the experimental evidence for allatotropin action, its localization in several species of insects, and its multiple effects on a variety of different tissues that lead to increased hemolymph circulation and gut motility. The overall physiological effects may also include species-specific effects such as the regulation of nutrient absorption, modulation of the circadian cycle and migratory preparedness. In addition, we present evidence suggesting that allatotropins are members of a family of myoactive peptides found in several invertebrate phyla. Finally, we speculate that the myoactive properties of allatotropins are basal and it is likely that the stimulatory action of allatotropins on juvenile hormone synthesis evolved secondarily.

Amino Acid Sequence↗
PubMed2005

Convergent evolution of invertebrate defensins and nematode antibacterial factors.

Antibacterial factors (ABFs) are secreted polypeptides that have an important role in the innate immune system of nematodes. Comparison of these polypeptides revealed similarity in bioactivity, protein sequence and 3D structure, suggesting that they originated from a common ancestor. Comparison of gene organization of nematode ABF genes revealed that all except one contain a Phase 0 intron at a conserved location. The intron phase and location are congruent with the postulated intron gain rules, suggesting a gain of intron before duplication and divergence of the ancestral gene. Although nematode ABFs display similarity in activity and structure to invertebrate (arthropod and mollusk) defensins, lack of sequence similarity and the different genomic organization suggest that these two polypeptide families exhibit convergent evolution.

Amino Acid Sequence↗
PubMed2003

Tyrosine kinases, synaptic plasticity and memory: insights from vertebrates and invertebrates.

Tyrosine kinases were first characterized in terms of their function during development. Over the past decade, it has become clear that tyrosine phosphorylation also plays an important role in the adult mammalian nervous system. This article reviews three different families of tyrosine kinase signaling cascades: the Trk receptor tyrosine kinases, the Src family of non-receptor tyrosine kinases and the Eph receptor tyrosine kinases. Each of these cascades has been implicated in both adult synaptic plasticity and memory formation. Evidence from invertebrate systems also demonstrates a role for tyrosine kinase signaling in the induction of long-term memory, suggesting that molecular mechanisms of memory formation are conserved across species.

Animals↗
PubMed2003

The kinetics of monospermic and polyspermic fertilization in free-spawning marine invertebrates.

The equation of Vogel et al. (1982) is widely used in fertilization studies of free-spawning marine invertebrates to predict the percentage of viable eggs that will be fertilized at any specified levels of gamete concentration and contact time. Here, the random collision model that underlies the Vogel et al. equation is extended to distinguish between monospermic and polyspermic fertilization, and separate equations for the percentages of monospermic and polyspermic fertilization are obtained. These equations provide an explanation for empirical observations which have shown a decreased percentage of successful egg development at high sperm concentrations. Comparison is made with an earlier heuristic attempt (Styan, 1998) to predict the extent of polyspermic fertilization, and it is found that this earlier method can underestimate the percentage of polyspermic fertilization by up to 10 percent. Moreover, the approach used here retains the flexibility to model changes in sperm concentration due to dispersal mechanisms, and is able to model different mechanisms for the block to polyspermy.

Animals↗
PubMed1998

Anti-inflammatory activity in mice of extracts from Mediterranean marine invertebrates.

The effects of dichloromethane and methanol extracts from the marine invertebrates Leptogorgia ceratophyta, Holothuria tubulosa, Coscinasterias tenuispina and Phallusia fumigata on carrageenan-induced paw oedema in mice were investigated. The dichloromethane extract of Coscinasterias tenuispina and the methanol extract of Holothuria tubulosa administered p.o. at 50, 100 and 150 mg/kg, inhibited oedema in a dose-dependent manner 3 h after administration of carrageenan. Both extracts partially decreased elastase activity and PGE2 levels measured in homogenates from inflamed paws, without affecting the levels of this prostanoid present in stomach homogenates. As observed with the selective inhibitor NS398, both extracts can decrease cyclo-oxygenase activity in inflamed tissues but do not modify the constitutive cyclo-oxygenase enzyme. Therefore, these extracts represent new marine resources for the isolation of novel agents active on inflammatory conditions.

Animals↗
PubMed2001

Trace metals in fish and invertebrates of three California coastal Wetlands.

Metal concentrations were measured in selected fish and invertebrate species from Mugu Lagoon, Malibu Lagoon and Ballona Wetlands in southern California in order to assess the extent of metal contamination in these three wetlands. Ranges of element concentrations (in microgram/g) found in biota were: Zn 12-650; Cu 1.9-440; Ni < 1-37; Cr < 1-55; Pb < 0.5-6.8; As < 1-8.5; Se < 1-3.8; Cd < 0.2-0.90; and Ag < 0.3-5.9. Relative to previous studies of California biota, the highest metal concentrations found were for chromium and nickel. The highest levels were in one of the two bottom-dwelling fish (juvenile Leptocottus armatus) (55 micrograms/g) and the two water-column fish sampled (Fundulus parvipinnis and Atherinops affinis) (30 and 24 micrograms/g). At Ballona Lagoon, elevated levels of copper and silver were found in the bivalve Tagelus californianus (440 and 5.9 micrograms/g). Chromium and nickel appeared to be most persistent in fish from Mugu (4.6-55 and 2.6-37 micrograms/g), the most northern site and an active military base, and Ballona (< 1-30 and < 1-16 micrograms/g), believed to be the most metal-contaminated site. Compared to previously measured metal concentrations in species of California coastal waters, these regions revealed higher levels of chromium, nickel, silver, arsenic, zinc, copper and, to a lesser extent, cadmium and selenium. Chromium and silver were present at high enough levels at all three sites to be considered environmental health hazards.

Animals↗
PubMed2003

The effect of the Jessica grounding on subtidal invertebrate and plant communities at the Galápagos wreck site.

Impacts of the grounding of the oil tanker Jessica off San Cristóbal island, Galápagos, included both effects of oil on biota and also mechanical effects associated with a shallow furrow 50 m x 30 m gouged across the rocky seafloor and wreckage strewn over 7500 m(2). The wreckage represented a minor but potentially chronic source of pollution to the surrounding environment through delayed releases of oil, antifouling compounds and other toxic chemicals, and a possible source of exotic marine taxa. Investigation at the wreck site indicated that impacts on subtidal plant and macro-invertebrate communities were largely confined within 100 m of the wreck site itself. Observed population effects included significant increases in cover of opportunistic algae (filamentous green algae, filamentous red algae and Ulva sp.) and the hydroid Ectopleura media adjacent to the wreck, while densities of the green sea urchin Lytechinus semituberculatus significantly decreased from 0.3 m(-2) adjacent to the wreck to 11 m(-2) at 100 m distance.

Accidents↗
PubMed1998

The chemosensitizers of multixenobiotic resistance mechanism in aquatic invertebrates: a new class of pollutants.

Mechanism of multixenobiotic resistance (MXR), identical to multidrug resistance (MDR) in tumor cells, has been found in aquatic invertebrates. The presence of this ATP-dependent membrane P-glycoprotein (Pgp) pump was confirmed by biochemical ('binding'), molecular (immunohistochemical, Western, Northern), physiological (verapamil-sensitivity) and toxicological (modulation of toxicity) methods. The inducibility of MXR in the presence of xenobiotics and its wide taxonomic distribution suggests its role as a general biological defense mechanism that rescues organisms by pumping potentially toxic xenobiotics out of the cells. Some xenobiotics, the chemosensitizers, can inhibit this defense mechanism. The presence of these MXR-inhibitors has important implications on environmental parameters like exposure, uptake, internal dose, bioaccumulation, response, synergism and toxicity. Such MXR-inhibitors, for example, enhance the accumulation of carcinogenic aromatic amines in mussel, with subsequent enhancement in production of their mutagenic metabolites, in induction of single strand breaks in DNA, and in induction of DNA-adducts. The property to inhibit defense mechanism of organisms classifies MXR-inhibitors among top-hazardous environmental chemicals. Therefore, we measured the concentration of chemosensitizers in water concentrates or sediment extracts as their potential to modulate the accumulation of fluorescent dyes in a cell-culture of NIH 3T3 mouse fibroblasts stable transfected with human MDR1 gene, or as the potential of native waters to decrease the efflux-rate of Rhodamine B from gills of mussels. We found significantly higher concentrations of MXR-inhibitors in samples from polluted marine sites or from polluted rivers than in samples from corresponding unpolluted sites. These concentrations were able to enhance the accumulation of fluorescent dyes or carcinogenic aromatic amines in clams, mussels, snails and sponges exposed to these xenobiotics, demonstrating the ecotoxicological relevance of MXR-inhibitors present in polluted waters.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2003

Effects of sampling, preparation and defecation on metal concentrations in selected invertebrates at urban sites.

In order to obtain basic information for designing standardized test preparation methods, the heavy metals Zn, Cu, Cd and Pb were measured in gastropods (Xerolenta obvia), oligochaetes (Lumbricus terrestris), isopods (Armadillidium vulgare, Trachelipus rathkei) and carabids (Harpalus rubripes, Calathus fuscipes) using different sampling methods and different modes of sample treatment. In some of the experiments, higher Zn, Cd and Pb, and lower Cu-contents were observed in isopods and carabids trapped with formalin-pitfalls compared to manually collected specimens (which were allowed to defecate). Defecation had marked effects on the levels of all four metals investigated in oligochaetes, and on Cd and Pb in gastropods and isopods. Cellulose was fed as an accelerator of gut passage and showed a significant effect on the Pb concentration in the soft body of gastropods. Deionate-washed isopods (A. vulgare) showed higher Cd concentrations than ultrasonic-cleaned individuals. No marked differences were observed between heat-dried and freeze-dried isopods. Carabids showed strong sex-specific differences in metal concentrations. Based on these and previous results, invertebrates should be: collected in vivo, allowed to defecate, be freeze-fixed and (at least in arthropods) ultrasonic-cleaned, determined to species level and in certain groups (carabids) also to sex, and then be sized or sorted by size (age) before further preparation and analysis. If any of these treatments is impractical, comparable sampling and preparation methods are recommended as a minimum requirement in order to avoid bias in the results and/or interpretation.

Animals↗
PubMed2003

Bioaccumulation of PCBs and chlorinated pesticides in seals, fishes and invertebrates from the White Sea, Russia.

Persistent organochlorines (OC) contaminants, including polychlorinated biphenyl (PCB) congeners, Dichlorophenyltrichloroethane (DDT)- and chlordane (CHL) related compounds, hexachlorocyclohexanes (HCH) isomers and chlorobenzenes (CBz) were determined in blubber of harp seals (Phoca groenlandica), ringed seals (Phoca hispida) and bearded seals (Eringnathus barbatus) as well as in fishes and invertebrates from the White Sea, in northwest Russia. Highest summation operator PCB and summation operator DDT concentrations were found in samples from two male bearded seals (means of 4150 ng/g lw and 3950 ng/g lw, respectively). Female harp seals had mean summation operator PCB and summation operator DDT concentrations of 1070+/-504 ng/g lw and 619+/-328 ng/g lw, respectively. Male and female adult ringed seals had similar mean summation operator PCB concentrations as harp seals (955+/-385 ng/g lw and 999+/-304 ng/g lw, respectively). summation operator CHL concentrations ranged from 63+/-29 ng/g lw in blubber of female adult ringed seals, to 322+/-156 ng/g lw in adult harp seals and averaged 465 ng/g lw in bearded seals. HCH isomers, mirex and chlorobenzenes were detected in all seal samples but were present at lower levels than summation operator CHL, summation operator DDT and summation operator PCB. Concentrations of summation operator CHL, summation operator DDT and summation operator PCB in ringed seals from the White Sea were within the range reported for the Barents Sea but lower than in ringed seals from the Kara Sea. Temporal trends were investigated by comparing concentrations of OCs in blubber of harp seal pups collected in 1992 with pups of the same age collected in 1998. The declines over the 6 year period ranged from approximately 33% for summation operator DDT to 60% for summation operator PCB. These declines are consistent with reports of declining concentrations summation operator DDT in seawater from the White Sea and inflowing rivers in the 1980's and early 1990s. The major OC contaminants in fishes from the White Sea were DDT-related compounds and PCBs. Navaga (Eleginus navaga) had the highest concentrations of the 5 fish species studied with mean summation operator PCB of 41+/-6 ng/g wet wt. while lowest mean concentrations were present in cod muscle (16+/-8 ng/g ww). Concentrations of hexachlorobenzene (HCB), DDT, CHL-related compounds and PCB congeners were strongly correlated with trophic level of the organisms assigned using delta(15)N values, while beta-HCH, gamma-HCH and cis-chlordane showed no relationship with trophic level. Food web magnification factors (FWMFs) for p,p'-DDE, alpha-HCH, oxychlordane and trans-nonachlor the White Sea were similar to those from marine food webs in the Barents Sea and the Canadian arctic, while FWMFs for HCB and PCBs were generally lower. Overall the results suggest that the White Sea marine food differs in terms of the availability of contaminants in comparison to studies of open ocean arctic food webs due to proximity to urban/industrial areas and greater importance of benthic food sources.

Adipose Tissue↗
PubMed1998

Intracellular proteinases of invertebrates: calcium-dependent and proteasome/ubiquitin-dependent systems.

Cytosolic proteinases carry out a variety of regulatory functions by controlling protein levels and/or activities within cells. Calcium-dependent and ubiquitin/proteasome-dependent pathways are common to all eukaryotes. The former pathway consists of a diverse group of Ca(2+)-dependent cysteine proteinases (CDPs; calpains in vertebrate tissues). The latter pathway is highly conserved and consists of ubiquitin, ubiquitin-conjugating enzymes, deubiquitinases, and the proteasome. This review summarizes the biochemical properties and genetics of invertebrate CDPs and proteasomes and their roles in programmed cell death, stress responses (heat shock and anoxia), skeletal muscle atrophy, gametogenesis and fertilization, development and pattern formation, cell-cell recognition, signal transduction and learning, and photoreceptor light adaptation. These pathways carry out bulk protein degradation in the programmed death of the intersegmental and flight muscles of insects and of individuals in a colonial ascidian; molt-induced atrophy of crustacean claw muscle; and responses of brine shrimp, mussels, and insects to environmental stress. Selective proteolysis occurs in response to specific signals, such as in modulating protein kinase A activity in sea hare and fruit fly associated with learning; gametogenesis, differentiation, and development in sponge, echinoderms, nematode, ascidian, and insects; and in light adaptation of photoreceptors in the eyes of squid, insects, and crustaceans. Proteolytic activities and specificities are regulated through proteinase gene expression (CDP isozymes and proteasomal subunits), allosteric regulators, and posttranslational modifications, as well as through specific targeting of protein substrates by a diverse assemblage of ubiquitin-conjugases and deubiquitinases. Thus, the regulation of intracellular proteolysis approaches the complexity and versatility of transcriptional and translational mechanisms.

Animals↗
PubMed2001

Detecting environmental impacts on metapopulations of mound spring invertebrates: assessing an incidence function model.

We use a stochastic patch occupancy model of invertebrates in the Mound Springs ecosystem of South Australia to assess the ability of incidence function models to detect environmental impacts on metapopulations. We assume that the probability of colonisation decreases with increasing isolation and the probability of extinction is constant across spring vents. We run the models to quasi-equilibrium, and then impose an impact by increasing the local extinction probability. We sample the output at various times pre- and postimpact, and examine the probability of detecting a significant change in population parameters. The incidence function model approach turns out to have little power to detect environmental impacts on metapopulations with small numbers of patches.

Animals↗
PubMed2000

Invertebrate molecular neuroimmune processes.

During the course of evolution, invertebrates and vertebrates have kept in common similar signaling molecules e.g. neuropeptides, opiates etc... Complete hormonal-enzymatic systems such as the opioid-opiate-cannabinoid systems have been found in both nervous central and immune systems of these animals. These signaling molecules can be found free in blood circulation and act as immunomodulators. The present review is focused on peptides derived from the opioid proopiomelanocortin precursor, the opiates and the endocannabinoids, which are very powerful immunosuppressors, and example models of the bidirectional communications between the endocrine and the immune systems. Parasites use these immunosuppressors with magnificence in their crosstalk with their host.

Animals↗
PubMed2002

Tolerance to biodegraded crude oil in marine invertebrate embryos and larvae is associated with expression of a multixenobiotic resistance transporter.

The toxicity of water-soluble fractions of biodegraded crude oil (BWSF) to embryos and larvae of two marine invertebrates, the white sea urchin (Lytechinus anamesus) and the fat innkeeper (Urechis caupo), was studied. Santa Barbara Channel crude oil was artificially weathered and subjected to biodegradation using a mixed microbe culture obtained from natural oil seep sites. The degradation culture inoculated with seep sediment microbes accumulated 43.7 microg/l water-soluble hydrocarbons. In contrast water-soluble fractions from the non-degraded cultures (NWSF) only accumulated 3.05 microg/l. BWSF proved deleterious to Lytechinus embryo development at low concentrations (EC50 = 0.33 mg/l) but was essentially non-toxic to Urechis embryos/larvae up to 3.0 mg/l. An established mechanism for handling of a wide array of xenobiotics in Urechis embryos is the multixenobiotoic resistance transporter multixenobiotic response (MXR, also known as multidrug resistance, MDR). This mechanism is primarily mediated by ATP-dependent, efflux pumps that extrude a wide array of xenobiotic compounds. In this study, we show that Lytechinus larvae do not appear to express MXR efflux protein nor MXR mediated dye efflux capacity. In contrast, BWSF acts as a competitive inhibitor of MXR transport-mediated dye efflux in Urechis larvae. These results suggest that MXR may be an important mechanism for extrusion of the by-products of crude oil degradation by microbes, and that the level of its expression may determine the susceptibility of organisms to degraded oil hydrocarbons.

Adaptation, Physiological↗
PubMed2001

Interspecific variation in heavy metal body concentrations in Hong Kong marine invertebrates.

Accumulated body concentrations of cadmium, copper and zinc were investigated in 19 species of intertidal invertebrates (the barnacles Tetraclita squamosa, Capitulum mitella, Balanus amphitrite, Megabalanus volcano, the bivalves Saccostrea cucullata, Septifer virgatus and Brachidontes atratus, the chiton Acanthopleura japonica and the gastropods Cellana grata, Cellana toreuma, Patelloida saccharina, Patelloida pygmaea, Siphonaria japonica, Tegula argyrostoma, Lunella coronata, Monodonta labio, Nerita albicilla, Thais clavigera and Thais luteostoma) collected from a relatively unpolluted area in Hong Kong, i.e. two shores within the Cape d'Aguilar Marine Reserve. In general body metal concentrations could be explained by the accumulation strategy of the analysed organism and by physiological requirements for the essential metals, i.e. copper and zinc. Zinc concentrations were, therefore, greatest in the barnacles and the oyster S. cucullata. Copper concentrations were greatest in those gastropods containing the respiratory pigment haemocyanin and in S. cucullata. One species collected from the sheltered shore, i.e. T. luteostoma, had much higher copper body concentrations compared with exposed shore conspecifics and this may be attributed to a diet that was dominated by oysters, which have high copper body concentrations. In contrast to both copper and zinc, cadmium body concentrations showed little interspecific variation.

Animals↗
PubMed2002

Evidence of differences in the biotransformation of organic contaminants in three species of freshwater invertebrates.

Acute static bioassays were performed using three freshwater invertebrate species (the oligochaete Lumbriculus variegatus, the fingernail clam Sphaerium corneum and the larvae Chironomus riparius) exposed separately to a variety of 14C radiolabelled contaminants. The aim of this work was to investigate if the chemicals remained as parent compounds after the treatments. Chemicals used were 2,4-dichlorophenol; 2,4,5-trichlorophenol; pentachlorophenol; pyrene; Fenpropidin, and Trifluralin. Homogenates of the whole body tissue of each organism were prepared and total radioactivity was measured. Contaminants were then extracted into organic solvents and analysed by high-pressure liquid chromatography techniques. Chromatograms showed that most of the substances extracted were present as parent compounds in S. corneum and in L. variegatus. In contrast, for C. riparius a low proportion of the chemicals was recovered as parent compounds. These results suggest that different metabolic processes could take place in the different species.

Animals↗