Distribution by Scientific Domains
Distribution within Life Sciences

Terms modified by Invertebrate

  • invertebrate abundance
  • invertebrate animals
  • invertebrate assemblage
  • invertebrate biomass
  • invertebrate colonization
  • invertebrate community
  • invertebrate density
  • invertebrate diet
  • invertebrate diversity
  • invertebrate drift
  • invertebrate fauna
  • invertebrate herbivore
  • invertebrate herbivory
  • invertebrate larva
  • invertebrate models
  • invertebrate nervous system
  • invertebrate order
  • invertebrate organism
  • invertebrate population
  • invertebrate predator
  • invertebrate prey
  • invertebrate species
  • invertebrate system
  • invertebrate taxa

  • Selected Abstracts

    Genome-wide identification of female-enriched genes in zebrafish

    Chaoming Wen
    Abstract Characteristic differences in morphology, physiology, and behavior between a male and female are correlated to the differential selection of sex-dependent transcriptomes. By using a cDNA array carrying ,9,000 zebrafish unique genes, we identified a group of genes whose expression are enriched in the female fish. A subset of these genes have been confirmed and further grouped as egg-enriched genes, as both somatic- and egg-enriched genes or as somatic-enriched genes by means of RNA gel blot hybridization. Most importantly, a significant proportion of these genes are either functionally unknown or are novel genes. Thus, future studies of this group of genes will help us greatly to understand more about sex-determination and sex-related physiology and behavior. In addition, comparison of zebrafish female-enriched genes with that in Drosophila, we found that only germline genes are shared between vertebrate and invertebrate, suggesting that the process of oogenesis is highly conserved during the evolution. Developmental Dynamics 232:171,179, 2005. © 2004 Wiley-Liss, Inc. [source]

    Integrating highly diverse invertebrates into broad-scale analyses of cross-taxon congruence across the Palaearctic

    ECOGRAPHY, Issue 6 2009
    Andreas Schuldt
    Our knowledge on broad-scale patterns of biodiversity, as a basis for biogeographical models and conservation planning, largely rests upon studies on the spatial distribution of vertebrates and plants, neglecting large parts of the world's biodiversity. To reassess the generality of these patterns and better understand spatial diversity distributions of invertebrates, we analyzed patterns of species richness and endemism of a hyperdiverse insect taxon, carabid beetles (ca 11 000 Palaearctic species known), and its cross-taxon congruence with well-studied vertebrates (amphibians, reptiles) and plants across 107,units of the Palaearctic. Based on species accumulation curves, we accounted for completeness of the carabid data by separately examining the western (well-sampled) and eastern (partly less well-sampled) Palaearctic and China (deficient data). For the western Palaearctic, we highlight overall centers of invertebrate, vertebrate and plant diversity. Species richness and endemism of carabids were highly correlated with patterns of especially plant and amphibian diversity across large parts of the Palaearctic. For the well-sampled western Palaearctic, hotspots of diversity integrating invertebrates were located in Italy, Spain and Greece. Only analysis of Chinese provinces yielded low congruence between carabids and plants/vertebrates. However, Chinese carabid diversity is only insufficiently known and China features the highest numbers of annual new descriptions of carabids in the Palaearctic. Even based on the incomplete data, China harbors at least 25% of all Palaearctic carabid species. Our study shows that richness and endemism patterns of highly diverse insects can exhibit high congruence with general large scale patterns of diversity inferred from plants/vertebrates and that hotspots derived from the latter can also include a high diversity of invertebrates. In this regard, China qualifies as an outstanding multi-taxon hotspot of diversity, requiring intense biodiversity research and conservation effort. Our findings extend the limited knowledge on broad-scale invertebrate distributions and allow for a better understanding of diversity patterns across a larger range of the world's biodiversity than usually considered. [source]

    Environmentally induced migration: the importance of food

    ECOLOGY LETTERS, Issue 6 2006
    Ivan C. Olsson
    Abstract The decision to migrate or not is regarded as genetically controlled for many invertebrate and vertebrate taxa. Here, we show that the environment influences this decision. By reciprocally transplanting brown trout (Salmo trutta L.) between two sections in a river, we show that both migratory and non-migratory behaviour can be environmentally induced; migratory behaviour developed in a river section with high brown trout densities and low specific growth rates, whereas non-migratory behaviour developed in a section with low brown trout densities and high specific growth rates. In a laboratory experiment, we tested the effect of food availability on the development of migratory and non-migratory body morphologies and found that most brown trout became migrants when food levels were low but fewer did so at high food levels. Thus, the decision to migrate seems to be a plastic response, influenced by growth opportunities. [source]

    Cholinesterase activity and behavior in chlorpyrifos-exposed Rana sphenocephala tadpoles

    Pamela D. Widder
    Abstract Recent studies have found a correlation between organophosphate (OP) pesticide exposure and declines in amphibian populations. We evaluated the hypothesis that this relationship is driven by behavioral changes in developing larvae. Specifically, we examined how exposure to a common OP pesticide, chlorpyrifos, influenced cholinesterase (ChE) activity, mass, and swim speed in Rana sphenocephala tadpoles. We also determined how the presence of natural pond sediments in exposure chambers influenced response to the pesticide and how mass and survival were affected when tadpoles were exposed to an invertebrate (odonate) predator in addition to the pesticide. Mass and swim speed were measured after 4- and 12-d laboratory exposures to 1, 10, 100, and 200 ,g/L of chlorpyrifos in test chambers that either did or did not contain pond sediments. These same parameters also were examined in mesocosms dosed with 200 ,g/L of chlorpyrifos to evaluate responses under more environmentally realistic conditions. The effect of the invertebrate predators on survival and/or growth of tadpoles was evaluated in the mesocosm study and in separate laboratory experiments. In laboratory tests, no pesticide-induced mortality was observed; however, tadpole ChE activity in the two highest concentrations was significantly lowered, with a longer exposure duration further decreasing activity (maximum inhibition, 43%). Mass also was lower at higher concentrations, but this effect was not enhanced with longer duration of exposure. Reductions in ChE activity of tadpoles exposed in mesocosms were similar to those observed in laboratory experiments for the first 4 d. Tadpole swim speed and survival in the presence of a predator were not affected, with the latter largely resulting from pesticide-induced predator mortality. [source]

    Transfer of Cd, Cu, Ni, Pb, and Zn in a soil-plant-invertebrate food chain: A microcosm study,

    Renaud Scheifler
    Abstract The transfer of Cd, Cu, Ni, Pb, and Zn was evaluated in a soil-plant (lettuce, Lactuca sativa),invertebrate (snail, Helix aspersa) food chain during a microcosm experiment. Two agricultural soils, polluted and unpolluted, were studied. Lettuce was cultivated for eight weeks before introduction of snails into the microcosms (M-snails). In a parallel experiment, snails were exposed to lettuce only (i.e., without soil) in simpler exposure devices called containers (C-snails). Snail exposure duration was eight weeks for both M- and C-snails. No effects on snail survival were found. Both M- and C-snails exposed to polluted soil showed a growth reduction, but only after two weeks of exposure. Time-dependent accumulation in M-snails exposed to the polluted environment showed a regular increase of Cd and Zn concentrations over time and a rapid increase of Pb concentrations within the first two weeks, which then remained stable. Copper and Ni concentrations did not increase during any of the experiments. Concentrations in M- and C-snails were compared to estimate the relative contribution of soil and plant to the total bioaccumulation. The results suggest that the soil contribution may be higher than 80% for Pb, from 30 to 60% for Zn, and from 2 to 40% for Cd. [source]

    Uptake and accumulation of sediment-associated 4-nonylphenol in a benthic invertebrate (Lumbriculus variegatus, freshwater oligochaete)

    Valeria Croce
    Abstract In the present work, the oligochaete Lumbriculus variegatus was exposed for 56 d to lake sediment spiked with 4-nonylphenol (4-NP), which is a breakdown product of alkylphenol polyethoxylates, an important class of nonionic surfactants. During the exposure period, the content of 4-NP was determined in the oligochaetes, sediment, overlying water, and pore water in order to monitor the distribution of the 4-NP in the compartments of the test system. Concentration of 4-NP in L. variegatus increased linearly over the course of the test, with an uptake rate coefficient of 1.9 × 10,2 (± 0.2 × 10,2; [g carbon/(g lipid-h)]). No steady state was reached at the end of the exposure period, suggesting that the elimination of 4-NP by the organism was negligible. Ingested sediments played an important role in the accumulation of 4-NP in L. variegatus, which may achieve very high 4-NP body concentrations. The 56-d biota sediment accumulation factor (BSAF) was 24 ± 7 g carbon/g lipid. L. variegatus also was exposed to 4-NP-contaminated field sediment, and field oligochaetes and sediments were collected for 4-NP pollution assessment in aquatic ecosystem. The 4-NP uptake with natural sediment was in accordance with that measured with spiked sediments, suggesting that the bioavailability of sediment-associated 4-NP for L. variegatus was not affected by 4-NP sediment concentration and abiotic sediment characteristics. The BSAFs measured in field oligochaetes, ranging from 39 to 55 g carbon/g lipid, was relatively higher than the bioaccumulation factor measured in laboratory tests. The results suggest that 4-NP concentration can reach high levels in benthic oligochaetes; this can be an important way of exposure for their pelagic predators. [source]

    Using artificial streams to assess the effects of metal-mining effluent on the life cycle of the freshwater midge (Chironomus tentans) in situ

    Kimberly A. Hruska
    Abstract In 2002, we developed an in situ life-cycle bioassay with Chironomus tentans in artificial streams to evaluate the effects of a complex metal mine effluent under ambient environmental conditions. The bioassay was tested in the field using effluent from the Copper Cliff Waste Water Treatment Plant at INCO (Sudbury, ON, Canada). Chironomus tentans were exposed throughout the life cycle to 45% Copper Cliff effluent, which is the average effluent concentration measured in Junction Creek (ON, Canada), the natural receiving environment. Chironomus tentans in the effluent treatment exhibited reduced survival (p = 0.001), reduced total emergence (p = 0.001), increased time-to-emergence (p = 0.001), and reduced hatching success (p = 0.001) relative to animals in the reference water treatment. Chironomus tentans in the effluent treatment were not significantly different from the reference in terms of growth, sex ratio, number of egg cases/female, and number of eggs/egg case. This research showed how a life-cycle bioassay could be used in situ to assess metal mine effluent effects on a benthic invertebrate. [source]

    Ecotoxicologic impacts of agricultural drain water in the Salinas River, California, USA

    Brian S. Anderson
    Abstract The Salinas River is the largest of the three rivers that drain into the Monterey Bay National Marine Sanctuary in central California (USA). Large areas of this watershed are cultivated year-round in row crops, and previous laboratory studies have demonstrated that acute toxicity of agricultural drain water to Ceriodaphnia dubia is caused by the organophosphate (OP) pesticides chlorpyrifos and diazinon. We investigated chemical contamination and toxicity in waters and sediments in the river downstream of an agricultural drain water input. Ecological impacts of drain water were investigated by using bioassessments of macroinvertebrate community structure. Toxicity identification evaluations were used to characterize chemicals responsible for toxicity. Salinas River water downstream of the agricultural drain was acutely toxic to the cladoceran Ceriodaphnia dubia, and toxicity to C. dubia was highly correlated with combined toxic units (TUs) of chlorpyrifos and diazinon. Laboratory tests were used to demonstrate that sediments in this system were acutely toxic to the amphipod Hyalella azteca, a resident invertebrate. Toxicity identification evaluations (TIEs) conducted on sediment pore water suggested that toxicity to amphipods was due in part to OP pesticides; concentrations of chlorpyrifos in pore water sometimes exceeded the 10-d mean lethal concentration (LC50) for H. azteca. Potentiation of toxicity with addition of the metabolic inhibitor piperonyl butoxide suggested that sediment toxicity also was due to other non,metabolically activated compounds. Macroinvertebrate community structure was highly impacted downstream of the agricultural drain input, and a number of macroinvertebrate community metrics were negatively correlated with combined TUs of chlorpyrifos and diazinon, as well as turbidity associated with the drain water. Some macroinvertebrate metrics were also correlated with bank vegetation cover. This study suggests that pesticide pollution is the likely cause of ecological damage in the Salinas River, and this factor may interact with other stressors associated with agricultural drain water to impact the macroinvertebrate community in the system. [source]


    EVOLUTION, Issue 1 2007
    Martin R. Miller
    There is a wide variety of resistance mechanisms that hosts may evolve in response to their parasites. These can be functionally classified as avoidance (lower probability of becoming infected), recovery (faster rate of clearance), tolerance (reduced death rate when infected), or acquired immunity. It is commonly thought that longer lived organisms should invest more in costly resistance. We show that due to epidemiological feedbacks the situation is often more complex. Using evolutionary theory we examine how the optimal investment in costly resistance varies with life span in a broad range of scenarios. In the absence of acquired immunity, longer lived populations do generally invest more in resistance. If hosts have acquired immunity, the optimal resistance may either increase or decrease with increasing life span. In addition, there may be evolutionary bistability with high and low investments in avoidance or tolerance. The optimal investment in the duration of acquired immunity always increases with life span, and due to bistability, shorter lived hosts may commonly not evolve any immunity. In contrast, the optimal investment in the probability of acquiring immunity initially increases and then decreases with life span. Our results have important implications for the evolution of invertebrate and vertebrate immunity, and for the evolution of acquired immunity itself. [source]

    Differential sensitivity to calciseptine of L-type Ca2+ currents in a ,lower'vertebrate (Scyliorhinus canicula), a protochordate (Branchiostoma lanceolatum) and an invertebrate (Alloteuthis subulata)

    Candida M. Rogers
    Voltage-dependent calcium currents in vertebrate (Scyliorhinus canicula), protochordate (Branchiostoma lanceolatum), and invertebrate (Alloteuthis subulata) skeletal and striated muscle were examined under whole-cell voltage clamp. Nifedipine (10 ,M) suppressed and cobalt (5 mM) blocked striated/skeletal muscle calcium currents in all of the animals examined, confirming that they are of the L-type class. Calciseptine, a specific blocker of vertebrate cardiac muscle and neuronal L-type calcium currents, was applied (0.2 ,M) under whole-cell voltage clamp. Protochordate and invertebrate striated muscle L-type calcium currents were suppressed while up to 4 ,M calciseptine had no effect on dogfish skeletal muscle L-type calcium currents. Our results demonstrate the presence of at least two sub-types of L-type calcium current in these different animals, which may be distinguished by their calciseptine sensitivity. We conclude that the invertebrate and protochordate L-type current sub-type that we have examined has properties in common with vertebrate ,cardiac' and ,neuronal' current sub-types, but not the skeletal muscle sub-type of the L-type channel. [source]

    Acetylcholinesterase from the invertebrate Ciona intestinalis is capable of assembling into asymmetric forms when co-expressed with vertebrate collagenic tail peptide

    FEBS JOURNAL, Issue 6 2008
    Adam Frederick
    To learn more about the evolution of the cholinesterases (ChEs), acetylcholinesterase (AChE) and butyrylcholinesterase in the vertebrates, we investigated the AChE activity of a deuterostome invertebrate, the urochordate Ciona intestinalis, by expressing in vitro a synthetic recombinant cDNA for the enzyme in COS-7 cells. Evidence from kinetics, pharmacology, molecular biology, and molecular modeling confirms that the enzyme is AChE. Sequence analysis and molecular modeling also indicate that the cDNA codes for the AChET subunit, which should be able to produce all three globular forms of AChE: monomers (G1), dimers (G2), and tetramers (G4), and assemble into asymmetric forms in association with the collagenic subunit collagen Q. Using velocity sedimentation on sucrose gradients, we found that all three of the globular forms are either expressed in cells or secreted into the medium. In cell extracts, amphiphilic monomers (G1a) and non-amphiphilic tetramers (G4na) are found. Amphiphilic dimers (G2a) and non-amphiphilic tetramers (G4na) are secreted into the medium. Co-expression of the catalytic subunit with Rattus norvegicus collagen Q produces the asymmetric A12 form of the enzyme. Collagenase digestion of the A12 AChE produces a lytic G4 form. Notably, only globular forms are present in vivo. This is the first demonstration that an invertebrate AChE is capable of assembling into asymmetric forms. We also performed a phylogenetic analysis of the sequence. We discuss the relevance of our results with respect to the evolution of the ChEs in general, in deuterostome invertebrates, and in chordates including vertebrates. [source]

    Novel ,-carboxyglutamic acid-containing peptides from the venom of Conus textile

    FEBS JOURNAL, Issue 12 2006
    Eva Czerwiec
    The cone snail is the only invertebrate system in which the vitamin K-dependent carboxylase (or ,-carboxylase) and its product ,-carboxyglutamic acid (Gla) have been identified. It remains the sole source of structural information of invertebrate ,-carboxylase substrates. Four novel Gla-containing peptides were purified from the venom of Conus textile and characterized using biochemical methods and mass spectrometry. The peptides Gla(1),TxVI, Gla(2),TxVI/A, Gla(2),TxVI/B and Gla(3),TxVI each have six Cys residues and belong to the O -superfamily of conotoxins. All four conopeptides contain 4- trans -hydroxyproline and the unusual amino acid 6- l -bromotryptophan. Gla(2),TxVI/A and Gla(2),TxVI/B are isoforms with an amidated C-terminus that differ at positions +1 and +13. Three isoforms of Gla(3),TxVI were observed that differ at position +7: Gla(3),TxVI, Glu7,Gla(3),TxVI and Asp7-Gla(3),TxVI. The cDNAs encoding the precursors of the four peptides were cloned. The predicted signal sequences (amino acids ,46 to ,27) were nearly identical and highly hydrophobic. The predicted propeptide region (,20 to ,1) that contains the ,-carboxylation recognition site (,-CRS) is very similar in Gla(2),TxVI/A, Gla(2),TxVI/B and Gla(3),TxVI, but is more divergent for Gla(1),TxVI. Kinetic studies utilizing the Conus,-carboxylase and synthetic peptide substrates localized the ,-CRS of Gla(1),TxVI to the region ,14 to ,1 of the polypeptide precursor: the Km was reduced from 1.8 mm for Gla (1),TxVI lacking a propeptide to 24 µm when a 14-residue propeptide was attached to the substrate. Similarly, addition of an 18-residue propeptide to Gla(2),TxVI/B reduced the Km value tenfold. [source]

    The potential role of waterbirds in dispersing invertebrates and plants in arid Australia

    FRESHWATER BIOLOGY, Issue 2 2008
    A. J. GREEN
    Summary 1. The role of waterbirds as vectors of plants and invertebrates within and between arid-zone wetlands is poorly understood. We present the first detailed study of passive dispersal by nomadic birds in Australasia. We investigated the numbers and types of invertebrate and plant propagules within freshly collected faecal samples as well as their viability. We compared dispersal among Grey Teal (Anas gracilis), Eurasian Coot (Fulica atra) and Black Swan (Cygnus atratus) in the Macquarie Marshes, a complex of temporary to semi-permanent wetlands in New South Wales. 2. When faecal samples (n = 60) were inundated in the laboratory and monitored over 3 weeks, ciliates (75% of samples), nematodes (22%), ostracods (13%) and rotifers (5%) were recorded, with higher taxon richness in coot samples. Faecal samples (n = 71) were also sieved to quantify intact propagules, and ostracod eggs (70% of samples), large branchiopod eggs (31%) and bryozoan statoblasts (31%) were the most abundant invertebrates. Diaspores of 19 plant taxa were recorded, 14 of which were germinated in the laboratory or shown to be viable at the end of germination trials. The abundance and diversity of invertebrate propagules was highest in coot samples, whereas the abundance and diversity of diaspores was highest in teal samples. 3. One Australian Pelican (Pelecanus conspicillatus) sample was obtained and found to contain more taxa and far more propagules than any sample from other waterbirds, suggesting that piscivorous birds might have an important role in the indirect dispersal of propagules ingested by fish. 4. Our results support a role for birds in explaining the distributions of cosmopolitan plant genera such as Lemna, Typha, Myriophyllum and Nitella. The alien plants Ranunculus sceleratus, Medicago polymorpha and Polygonum arenastrum were recorded, demonstrating the potential role of waterfowl in the spread of exotic species. As the frequency and duration of flooding of arid-zone wetlands decreases owing to human activities, the importance of waterbirds in facilitating recolonisation of temporary wetlands is likely to increase. [source]

    Generation of a germ cell-specific mouse transgenic Cre line, Vasa-Cre,

    Teresa Gallardo
    Abstract Cell type-specific genetic modification using the Cre/loxP system is a powerful tool for genetic analysis of distinct cell lineages. Because of the exquisite specificity of Vasa expression (confined to the germ cell lineage in invertebrate and vertebrate species), we hypothesized that a Vasa promoter-driven transgenic Cre line would prove useful for the germ cell lineage-specific inactivation of genes. Here we describe a transgenic mouse line, Vasa-Cre, where Cre is efficiently and specifically expressed in germ cells. Northern analysis showed that transgene expression was confined to the gonads. Cre-mediated recombination with the Rosa26-lacZ reporter was observed beginning at ,e15, and was >95% efficient in male and female germ cells by birth. Although there was a potent maternal effect with some animals showing more widespread recombination, there was no ectopic activity in most adults. This Vasa-Cre transgenic line should thus prove useful for genetic analysis of diverse aspects of gametogenesis and as a general deletor line. genesis 45:413,417, 2007. Published 2007 Wiley-Liss, Inc. [source]

    Palaeoenvironmental context of the Late-glacial woolly mammoth (Mammuthus primigenius) discoveries at Condover, Shropshire, UK

    GEOLOGICAL JOURNAL, Issue 4 2009
    J. R. M. Allen
    Abstract In 1986/1987 the remains of several mammoths, Mammuthus primigenius (Blumenbach), were discovered on the spoil heap of an actively working gravel pit at Condover, Shropshire, England. The discovery of the remains posed two questions that could be addressed by analyses of biological proxies. First, as none of the bones was found in situ it was necessary to confirm the stratum in which the remains occurred. Second, what was the environment in which these animals lived and died? A range of biological indicators was used to address these questions, including pollen, spore and algal, plant macrofossil, invertebrate, anuran and biological mineral analyses. Multivariate statistical analyses of palynological and Pediastrum data, along with evidence from the Coleopteran assemblages, support the attribution of the mammoth bones to a unit of dark grey clayey sandy silt, although they may have lived at the time of the overlying green detritus mud. The palaeobiological data supports the correlation of these sediments to the Devensian Late-glacial. The mammoths entered this basin at the start of the Late-glacial Interstadial (Greenland Interstadial 1e) (ca. 14,830,3930 cal. year BP; 12,300,±,110 14C year BP) and became mired in soft cohesive sediments. Palaeotemperature reconstructions, based on the Coleopteran assemblages, from the time when the mammoths actually became mired, show that the climate was temperate with mean July temperatures between 15 and 19°C and mean January temperatures between ,13 and +6°C. Biological indicators from the sediments encasing the mammoths indicate that the landscape surrounding the basin was treeless and dry, contrasting with rich vegetation within the basin itself that had possibly attracted the mammoths to the site. Evidence of sedimentary disturbance suggests that the mammoths caused large-scale bioturbation of the deposits making palaeoenvironmental interpretations difficult. Fossils of terrestrial blowflies, carcass and dung beetles show that some of the decaying corpses must have lain exposed on the land surface for sufficient time for the soft parts to have rotted away and skin and bones to have become desiccated before many of them sank into the dark grey clayey sandy silt. Copyright © 2009 John Wiley & Sons, Ltd. [source]

    Decline in a dominant invertebrate species contributes to altered carbon cycling in a low-diversity soil ecosystem

    Abstract Low-diversity ecosystems cover large portions of the Earth's land surface, yet studies of climate change on ecosystem functioning typically focus on temperate ecosystems, where diversity is high and the effects of individual species on ecosystem functioning are difficult to determine. We show that a climate-induced decline of an invertebrate species in a low-diversity ecosystem could contribute to significant changes in carbon (C) cycling. Recent climate variability in the McMurdo Dry Valleys of Antarctica is associated with changes in hydrology, biological productivity, and community composition of terrestrial and aquatic ecosystems. One of the greatest changes documented in the dry valleys is a 65% decrease in the abundance of the dominant soil invertebrate (Scottnema lindsayae, Nematoda) between 1993 and 2005, illustrating sensitivity of biota in this ecosystem to small changes in temperature. Globally, such declines are expected to have significant influences over ecosystem processes such as C cycling. To determine the implications of this climate-induced decline in nematode abundance on soil C cycling we followed the fate of a 13C tracer added to soils in Taylor Valley, Antarctica. Carbon assimilation by the dry valley nematode community contributed significantly to soil C cycling (2,7% of the heterotrophic C flux). Thus, the influence of a climate-induced decline in abundance of a dominant species may have a significant effect on ecosystem functioning in a low-diversity ecosystem. [source]

    Stress synergy between drought and a common environmental contaminant: studies with the collembolan Folsomia candida

    Rikke Højer
    Summary The term global change is used predominantly in connection with the global temperature increase and associated changes in weather patterns over the next century. In a broader sense it also covers other anthropogenic impacts on the environment such as habitat fragmentation and pollution. The individual effects of each of these stress types have been extensively studied in the biota. However, organisms will frequently encounter these stress types in combination rather than alone and there is little information available on the effects of stress combinations. Here an examination is made of the interaction between realistic levels of summer drought and a common contaminant of agricultural soil (4-nonylphenol, NP), on a widespread soil invertebrate, the collembolan Folsomia candida. These stress factors were tested individually and in combination using a full factorial design. This approach revealed the existence of highly significant Bliss type synergistic interaction between the two stress types. Thus, exposure to NP significantly reduced the drought tolerance of this organism and, reciprocally, the toxicity of NP (LC50) during realistic summer drought was more than doubled in comparison to the value obtained under optimal soil moisture conditions. Furthermore, it is shown that NP has a detrimental effect on the physiological mechanisms underlying this animal's drought tolerance, thus providing some explanation for the mechanisms involved in the synergy. It is argued that this type of synergy is unlikely to be confined to this particular combination of stresses and thus there is a need to study the interactions between dominant natural stresses and pollution. The most important implication of these results is that some of the effects of global climate changes can be predicted to be most severe in polluted areas. [source]

    Correlations between the Sonic Hedgehog Pathway and basal cell carcinoma

    Omar Lupi MD
    The Hedgehog (HH) family of intercellular signaling proteins has some essential functions in patterning both invertebrate and vertebrate embryos. Identified as an important regulator of segment polarity and tissue organization in flies, the HH pathway can also play a significant role in human development and in cutaneous carcinogenesis. The family received their name because when the D. melanogaster HH protein malfunctions the mutant fly ends up looking like a small prickly ball, similar to a curled up hedgehog. The Sonic hedgehog (SHH) pathway is implicated in the etiology of the most common human cancer, the basal cell carcinoma (BCC). Mutations in the receptor of SHH, the patched gene (PTCH), have been characterized in sporadic BCCs as well as those from patients with the rare genetic syndrome nevoid BCC. Human PTCH is mutated in sporadic as well as hereditary BCCs, and inactivation of this gene is probably a necessary if not sufficient step for tumorigenesis. Delineation of the biochemical pathway in which PTCH functions may lead to rational medical therapy for skin cancer and possibly other tumors. [source]

    Sirt1's beneficial roles in neurodegenerative diseases , a chaperonin containing TCP-1 (CCT) connection?

    AGING CELL, Issue 5 2010
    Bin Qi Gan
    Summary Sir2/Sirt1 and its orthologues are known lifespan extension factors in several aging models from yeast to invertebrates. Sirt1 activation is also known to be beneficial and protective in both invertebrate and mammalian models of neurodegenerative disease. Sirt1's lifespan extension effect, as well as the beneficial outcome of its activation in models of aging-associated diseases, is often attributed to its ability to instill a gene expression profile that is pro-survival and anti-aging. A recent report from Nyström and colleagues showed that the yeast Sir2p affects the function of the polarisome in segregation and retrograde transport of damaged and aggregated proteins from the bud to the mother cell, thereby ensuring the generation of a ,rejuvenated' daughter cell. Interestingly, the role of Sir2p in this case involves deacetylation and activation of cytoplasmic chaperonin containing TCP-1 (CCT, or TriC), thereby enhancing actin folding and polymerization. In view of a previously documented role of CCT in modulating polyglutamine-containing protein aggregation and toxicity, we hypothesized that CCT deacetylation may also underlie Sirt1's beneficial effects in several neurodegenerative diseases precipitated by toxic aggregates. Other than alterations in gene expression profile, another major way whereby Sirt1 activation may counter neural aging could be to promote neuronal survival via prevention of toxic aggregate formation through CCT. [source]

    Spatially structured genetic variation in a broadcast spawning bivalve: quantitative vs. molecular traits

    P. C. Luttikhuizen
    Abstract Understanding the origin, maintenance and significance of phenotypic variation is one of the central issues in evolutionary biology. An ongoing discussion focuses on the relative roles of isolation and selection as being at the heart of genetically based spatial variation. We address this issue in a representative of a taxon group in which isolation is unlikely: a marine broadcast spawning invertebrate. During the free-swimming larval phase, dispersal is potentially very large. For such taxa, small-scale population genetic structuring in neutral molecular markers tends to be limited, conform expectations. Small-scale differentiation of selective traits is expected to be hindered by the putatively high gene flow. We determined the geographical distribution of molecular markers and of variation in a shell shape measure, globosity, for the bivalve Macoma balthica (L.) in the western Dutch Wadden Sea and adjacent North Sea in three subsequent years, and found that shells of this clam are more globose in the Wadden Sea. By rearing clams in a common garden in the laboratory starting from the gamete phase, we show that the ecotypes are genetically different; heritability is estimated at 23%. The proportion of total genetic variation that is between sites is much larger for the morphological additive genetic variation (QST = 0.416) than for allozyme (FST = 0.000,0.022) and mitochondrial DNA cytochrome- c -oxidase-1 sequence variation (,ST = 0.017). Divergent selection must be involved and intraspecific spatial genetic differentiation in marine broadcast spawners is apparently not constrained by low levels of isolation. [source]

    Avifauna associated with ephemeral ponds on the Cumberland Plateau, Tennessee

    Brett R. Scheffers
    ABSTRACT Although ephemeral ponds act as small hotspots of plant, invertebrate, and salamander diversity, the importance of such ponds for birds has been little studied. We hypothesized that ephemeral ponds on the Cumberland Plateau in Tennessee would support a greater abundance, richness, and diversity of birds than the surrounding hardwood forests. In 2004, we recorded all birds seen or heard in 10 min within 50-m radius circles at 25 ephemeral ponds. We repeated the counts at control sites located 150 m from each pond in the surrounding forest. To quantify potential food availability, we captured aerial invertebrates using sweep nets at four points around a subsample of eight ephemeral ponds and at an equal number of control sites. We found significantly greater bird abundance, richness, and species diversity at ephemeral ponds than at control sites, and that pond area was not associated with either bird abundance or richness. Bird community composition at pond and control sites was similar. Aerial invertebrates were significantly more abundant at ephemeral ponds than at adjacent forest sites, providing one possible explanation for greater bird abundance at ephemeral ponds. SINOPSIS Aunque las charcas efímeras actúan como lugares claves para plantas, invertebrados y vertebrados como salamandras, la importancia de estas no ha sido objeto de estudio para aves. Pusimos a prueba la hipótesis de que charcas efímeras, sostendrían una mayor abundancia, riqueza y diversidad de aves que unos bosques secundarios encontrados en Cumberland Plateau, Tennessee. Durante el 2004 contabilizamos las aves observadas o escuchadas, durante un periodo de 10 minutos en círculos con radio de 50 m en 18 charcas efímeras. Como control, repetimos los conteos en los alrededores del bosque a distancias de 150 m de las charcas. Para cuantificar la disponibilidad potencial de alimentos, capturamos invertebrados aéreos utilizando redes de barrido en cuatro lugares como sub-muestras en ocho de las charcas y en un número similar de áreas con bosques. Encontramos un número significativo mayor de abundancia de aves, riqueza y diversidad de especies en las charcas efímeras que en los bosques. El área ocupada por las charcas no estuvo asociada ni a la riqueza o abundancia de aves. La composición de la comunidad de aves en las charcas y en los bosques resultó similar. La cantidad de invertebrados aéreos fue significativamente más abundante en las charcas que en los bosques adyacentes, lo que provee una explicación posible para la mayor abundancia de aves en las charcas. [source]

    Taphonomy of Child-Sized Remains: A Study of Scattering and Scavenging in Virginia, USA,

    Robert J. Morton M.S.
    ABSTRACT: Child-sized pig carcasses (Sus scrofa) were placed in surface deposit and buried scenarios in a wooded area of Virginia from May 1998 through December 2000, to examine the taphonomic effects of decompositional changes, predator scavenging, and the extent of remains scattering. Changes were observed through on-site examination, charting of remains, and recorded video imaging. Analysis of data revealed that utilization of corpses as food sources by vertebrates was dependent upon invertebrate colonization. Vertebrates avoided feeding on the corpses while invertebrate colonization was active, and would feed before invertebrates successfully colonized a corpse, or would wait until the invertebrate populations migrated away from the corpse. Among vertebrates, there was no apparent succession order for the animals utilizing the remains as a food source. Different vertebrates would feed at different times based upon diurnal or nocturnal predilection. Analysis noted an accidental cooperative relationship between the invertebrates and vertebrates scavenging on the corpses. Certain vertebrates gained access to the internal tissues by utilizing openings in the corpses caused by invertebrate and other vertebrate scavenging. Alternately, carrion-frequenting insects were afforded access to previously inaccessible colonization sites as a result of scavenging vertebrate activities. [source]

    TYRA-2 (F01E11.5): a Caenorhabditis elegans tyramine receptor expressed in the MC and NSM pharyngeal neurons

    Elizabeth Rex
    Abstract Tyramine appears to regulate key processes in nematodes, such as pharyngeal pumping, and more complex behaviors, such as foraging. Recently, a Caenorhabditis elegans tyramine receptor, SER-2, was identified that is involved in the TA-dependent regulation of these processes. In the present study, we have identified a second C. elegans gene, tyra-2 (F01E11.5) that encodes a tyramine receptor. This is the first identification of multiple tyramine receptor genes in any invertebrate. Membranes from COS-7 cells expressing TYRA-2 bind [3H]tyramine with high affinity with a Kd of 20 ± 5 nm. Other physiologically relevant biogenic amines, such as octopamine and dopamine, inhibit [3H]tyramine binding with much lower affinity (Kis of 1.55 ± 0.5 and 1.78 ± 0.6 ,m, respectively), supporting the identification of TYRA-2 as a tyramine receptor. Indeed, tyramine also dramatically increases GTP,S binding to membranes from cells expressing TYRA-2 (EC50 of 50 ± 13 nm) and the TA-dependent GTP,S binding is PTX-sensitive suggesting that TYRA-2 may couple to G,i/o. Based on fluorescence from tyra::gfp fusion constructs, TYRA-2 expression appears to be exclusively neuronal in the MC and NSM pharyngeal neurons, the AS family of amphid neurons and neurons in the nerve ring, body and tail. Taken together, these results suggest that TYRA-2 encodes a second G,i/o -coupled tyramine receptor and suggests that TA-dependent neuromodulation may be mediated by multiple receptors and more complex than previously appreciated. [source]

    Characterization of a novel G-protein coupled receptor from the parasitic nematode H. contortus with high affinity for serotonin

    Martin W. Smith
    The neurotransmitter serotonin (5HT) has been shown to modulate mobility, feeding, egg-laying, and defecation behaviors in the saprophytic nematode Caenorhabditis elegans. Although the effects of serotonin on these behaviors in parasitic nematodes is under study, little is known about the diversity, ontogeny, signaling, and pharmacology of serotonin receptors in these organisms. In an effort to increase our understanding of this system, we cloned and characterized a novel cDNA (5HT1Hc) from the parasitic nematode Haemonchus contortus that has high amino acid sequence homology with known G-protein coupled 5HT1-receptors from invertebrates and vertebrates. Transcript expression studies in four development stages (egg, L1/L2, L3, and adult) revealed the presence of the mRNA in the L1/L2, L3, and adult stages. Membranes from insect cells (Sf9) expressing the 5HT1Hc -receptor cDNA displayed nanomolar binding affinity to serotonin and a unique pharmacological profile distinct from known invertebrate and mammalian 5HT-receptors. Receptor signaling studies with mammalian AV12 cells expressing the 5HT1Hc -receptor and the promiscuous G-protein, G,15, demonstrated dose-dependent intracellular signals with serotonin acting as an agonist. Together, these studies describe a novel invertebrate 5HT-receptor with high affinity for the indolealkylamine, serotonin, and pharmacological properties that do not conform to any known members of this superfamily of metabotropic receptors. [source]

    Population genetics of the endangered limpet Patella ferruginea (Gastropoda: Patellidae): taxonomic, conservation and evolutionary considerations

    F. Espinosa
    Abstract The limpet Patella ferruginea is the most endangered marine invertebrate in the western Mediterranean rocky shores, whereas Patella caerulea is the most common Mediterranean limpet. From Pleistocene to historic age, P. ferruginea was distributed around the whole Mediterranean basin, since the shells of this species are a characteristic feature of Palaeolithic and Neolithic deposits in this area. However, its Mediterranean range has progressively contracted to a few restricted areas. The ancient origin of the species (18 Ma) and the present geographical isolation among relic populations could have led to a great genetic difference among populations, taking into account the supposedly low dispersal ability of the species. However, we have observed a few genetic differences among populations and a ,star phylogeny' of COI haplotypes from the 41 individuals of P. ferruginea analysed; a similar pattern has also been observed for the seven individuals of P. caerulea studied. Genetic evidences show a possible bottleneck event on late Pleistocene that affected the two species. The results have an important implication on the future management of this endangered species. Additionally, two different morphological types of P. ferruginea have been described by Payraudeau in 1826: lamarcki and rouxi forms. Clear morphological differences occur between these two types and some authors pointed out the hypothesis about the existence of two different species. The results of the present study conclude that the two different forms of P. ferruginea are ecotypes, rather than different species or subspecies, and intermediate steps are an ecological range instead of hybridization events among different species. Resumen Patella ferruginea es el invertebrado marino más amenazado de las costas del Mediterráneo occidental, mientras que Patella caerulea es una especie muy común. Desde el Pleistoceno hasta épocas históricas, P. ferruginea estuvo distribuída alrededor de toda la cuenca mediterránea, ya que su concha es característica de depósitos paleolíticos y neolíticos en esta área. Sin embargo, su rango de distribución se ha visto reducido a unas pocas áreas restringidas. Su orígen primitivo (18 Ma) y el presente aislamiento geográfico entre las poblaciones podría haber generado importantes diferencias genéticas inter-poblacionales, teniendo en cuenta la supuesta baja capacidad de dispersión de la especie. Sin embargo, se han observado pocas diferencias genéticas inter-poblacionales y una ,,filogenia en estrella'' de los haplotipos de la COI procedentes de los 41 individuos de P. ferruginea analizados, un patrón similar ha sido también observado para los 7 individuos de P. caerulea estudiados. Las evidencias genéticas sugieren un posible cuello de botella a finales del Pleistoceno que afectó a las dos especies. Estos resultados tienen gran importancia en la futura gestión de esta especie amenazada. Adicionalmente, Payraudeau en 1826 describió dos tipo morfológicos de P. ferruginea: formas rouxi y lamarcki. Importantes diferencias morfológicas aparecen entre las dos formas y algunos autores han señalado la hipótesis de que podrían ser dos especies distintas. Los resultados del presente estudio concluyen que las dos formas de P. ferruginea son ecotipos en lugar de especies o subespecies distintas, y que las formas intermedias serían parte de un rango ecológico en lugar de ser fenómenos de hibridación entre especies diferentes. [source]

    The oldest reptile in amber: a 120 million year old lizard from Lebanon

    JOURNAL OF ZOOLOGY, Issue 1 2002
    E. N. Arnold
    Abstract Animals enclosed in amber often provide a unique insight into their surface structure. Such fossils of reptiles are rare and usually not extremely ancient, the earliest being no more than 40 million years (my). A recently discovered 120 my lizard from the Lower Cretaceous of Lebanon provides direct evidence that several common external features of autarchoglossan lizards had evolved by this time. Ecomorphology indicates that the lizard concerned had considerable climbing ability on open surfaces and perhaps in vegetation, and probably lived in a mesic forested environment, something supported by associated plant and invertebrate remains. [source]

    Genetic parentage assessment in the crayfish Orconectes placidus, a high-fecundity invertebrate with extended maternal brood care

    MOLECULAR ECOLOGY, Issue 10 2002
    D. Walker
    Abstract Microsatellite data have recently been introduced in the context of genetic maternity and paternity assignments in high-fecundity fish species with single-parent-tended broods. Here we extend such analyses to an aquatic invertebrate, the crayfish Orconectes placidus, in which gravid females carry large numbers of offspring. Genetic parentage analyses of more than 900 progeny from 15 wild crayfish broods revealed that gravid females were invariably the exclusive dams of the offspring they tended (i.e. there was no allomaternal care), and that most of the females had mated with multiple (usually two) males who contributed sometimes highly skewed numbers of offspring to a brood. Within any multiply sired brood, the unhatched eggs (or the hatched juveniles) from different fathers were randomly distributed across the mother's brood space. All of these genetic findings are discussed in the light of observations on the mating behaviours and reproductive biology of crayfishes. [source]

    Molecular identification of prey in predator diets

    MOLECULAR ECOLOGY, Issue 4 2002
    W. O. C. Symondson
    Abstract In many situations prey choice by predators in the field cannot be established or quantified using direct observation. The remains of some prey may be visually identified in the guts and faeces of predators but not all predators ingest such hard remains and even those that do consume them may also ingest soft-bodies prey that leave no recognizable remnants. The result is, at best, a biased picture of prey choice. A range of molecular techniques and applications are reviewed that allow prey remains to be identified, often to the species and even stage level. These techniques, all of which are still in use, include enzyme electrophoresis, a range of immunological approaches using polyclonal and monoclonal antibodies to detect protein epitopes, and recently developed polymerase chain reaction (PCR)-based methods for detecting prey DNA. Analyses may be postmortem, on invertebrate and vertebrate predators collected from the field, or noninvasive assays of the remains in regurgitated bird pellets or vertebrate faeces. It was concluded that although monoclonal antibodies are currently the most effective method in use today, PCR-based techniques have proved to be highly effective and versatile in recent laboratory trials and are likely to rapidly displace all other approaches. [source]

    Gq-coupled Rhodopsin Subfamily Composed of Invertebrate Visual Pigment and Melanopsin,

    Mitsumasa Koyanagi
    Rhodopsins (rhodopsins and their related photopigments) are phylogenetically classified into at least seven subfamilies, which are also roughly discriminated by molecular function. The Gq-coupled rhodopsin subfamily, members of which activate the Gq type G protein upon light absorption, contains pigments which underlie both visual and nonvisual physiologic functions. Gq-coupled visual pigments have been found in the rhabdomeric photoreceptor cells of varied protostomes, and those of molluskans and arthropods have been extensively investigated. Recently, a novel photopigment, melanopsin, and its homologs have been identified in varied vertebrates. In mammals, melanopsin is localized in retinal ganglion cells and is involved in nonvisual systems, including circadian entrainment and pupillary light responses. More recently, we discovered a melanopsin homolog in amphioxus, the closest living invertebrate to vertebrates. Amphioxus melanopsin is localized in putative nonvisual photoreceptor cells with rhabdomeric morphology and exhibits molecular properties almost identical to those of invertebrate Gq-coupled visual pigments. The localization and properties of amphioxus melanopsin bridged the functional and evolutionary gap between invertebrate Gq-coupled visual pigments and vertebrate circadian photopigment melanopsins. Research into the Gq-coupled rhodopsin subfamily, especially invertebrate melanopsins, will provide an opportunity to investigate the evolution of various physiologic functions, based on orthologous genes, during animal evolution. [source]

    The enemy: a twenty-first century archetypal study

    Maxine Sheets-Johnstone
    Abstract This paper delineates the biologically based archetype of the enemy, showing how it derives ideationally and affectively from the archetype of the stranger, the latter an evolutionary given within the lives of animate creatures. In doing so, it both extends Jung's classic exposition of archetypes and sustains their relationship to instincts. It shows how globalization magnifies the archetype of the enemy; how, in a living sense, stranger and archetype are taxonomically distinct; and how, just as the enemy is the cultural elaboration of the biologically based archetype of the stranger, so war is the cultural elaboration of male-male competition. In elucidating these aspects of the enemy, it makes explicit reference to Darwin's lengthy descriptive writings about male-male competition across invertebrate and vertebrate species. Key implications and ramifications are discussed on the basis of both Jung's and Darwin's insights into what is commonly known as ,the mind/body problem.' Copyright © 2010 John Wiley & Sons, Ltd. [source]