183 research outputs found
The abundances and distributions of molluscs in the southern Iberian Peninsula: A comparison of marine and terrestrial systems
Molluscs are the second most diverse of all animal phyla, and occur in many habitat types.
They are, therefore, a particularly good phylum with which to compare and contrast differences
between ecosystems. Mollusc data from a number of sites along the southern coast of the Iberian
Peninsula are analysed to study patterns of diversity and distribution using a range of multivariate
techniques. Within each site, data are presented from three locations -fully terrestrial, rocky
intertidal and soft bottom benthic (10 m and 20 m depths)- all in close proximity. The species are
then classified in relation to morphology and size, and analysed at supraspecific levels to elucidate
underlying patterns. The observed patterns are briefly discussed, with particular reference
to the differential scope and importance of controlling factors in each ecosystem, such as dispersal
processes. The results from the systems are compared and discussed in the context of ecological
and evolutionary constraints in MolluscaLos moluscos constituyen el segundo filo animal más diverso y se encuentran en muchos tipos de hábitat,
por lo que son idóneos para establecer comparaciones entre distintos ecosistemas.
Se han analizado los datos de los moluscos obtenidos en una serie de emplazamientos que cubrían el sur
de la península Ibérica para determinar, empleando distintas técnicas multivariantes, los patrones de diversidad
y distribución de estos organismos. Los datos se tomaron de ejemplares capturados en lugares del medio
terrestre próximos a la línea de costa, de la franja intermareal rocosa y de sedimentos de fondos marinos situados
a 10 y 20 m de profundidad. Las especies fueron clasificadas atendiendo a la morfología y el tamaño,
y se analizaron a nivel supraespecífico para elucidar los patrones generales, que se discuten aquí, brevemente,
con especial énfasis en las diferencias según la importancia de los factores que controlan cada
ecosistema, como, por ejemplo, los procesos de dispersión. Los resultados de los distintos sistemas se comparan
y discuten en el contexto de las tendencias ecológicas y evolutivas de los molusco
The littoral sea cucumbers (Echinodermata: Holothuroidea) of Guam re-assessed - a diversity curve that still does not asymptote
The Micronesian island of Guam has been an important site for the study of littoral tropical holothuriantaxonomy for almost 200 years. Despite substantial attention by both expeditions and resident taxonomists, new records arestill regularly added to the fauna, demonstrating the challenge of documenting even such large and well-known animals ina small hyper-diverse area. Guam is the type locality of species described by Quoy & Gaimard (1833) and Brandt (1835).A survey of the sea cucumber fauna by Rowe & Doty (1977) led to one of the most used guides for the identification oftropical Pacific sea cucumbers because of the color illustrations of living animals it presented. Focus on echinodermsincluding holothurians continued with numerous new records added in the following decades. Paulay (2003a) summarizedthe fauna last, recording 46-47 species. At this stage the fauna was thought to be well documented. A week-long workshopon holothurian systematics sponsored by the National Science Foundation PEET (Partnerships for Enhancing Expertise inTaxonomy) project in 2010 included a substantial field work component, sampling both during the day and night, withsnorkeling and SCUBA, across a variety of habitats. This survey yielded 40 species, including numerous new records andeven species. Further sampling by Kerr’s lab since the workshop has added additional records. The littoral holothuroidfauna of Guam now comprises 65 species in 17 genera and 7 families. Half of the 19 newly recorded species are the resultof unravelling cryptic species in complexes, the other half are based on new collections. Eleven species are known fromsingle specimens, suggesting that much still remains to be learned about the fauna
Scanning mutagenesis of omega-atracotoxin-Hv1a reveals a spatially restricted epitope that confers selective activity against insect calcium channels
We constructed a complete panel of alanine mutants of the insect-specific calcium channel blocker omega-atracotoxin-Hv1a. Lethality assays using these mutant toxins identified three spatially contiguous residues, Pro(10), Asn(27), and Arg(35), that are critical for insecticidal activity against flies (Musca domestica) and crickets (Acheta domestica). Competitive binding assays using radiolabeled omega-atracotoxin-Hv1a and neuronal membranes prepared from the heads of American cockroaches (Periplaneta americana) confirmed the importance of these three residues for binding of the toxin to target calcium channels presumably expressed in the insect membranes. At concentrations up to 10 muM, omega-atracotoxin-Hv1a had no effect on heterologously expressed rat Ca(v)2.1, Ca(v)2.2, and Ca(v)1.2 calcium channels, consistent with the previously reported insect selectivity of the toxin. 30 muM omega-atracotoxin-Hv1a inhibited rat Ca-v currents by 10-34%, depending on the channel subtype, and this low level of inhibition was essentially unchanged when Asn(27) and Arg(35), which appears to be critical for interaction of the toxin with insect Ca-v channels, were both mutated to alanine. We propose that the spatially contiguous epitope formed by Pro(10), Asn(27), and Arg(35) confers specific binding to insect Ca-v channels and is largely responsible for the remarkable phyletic selectivity of omega-atracotoxin-Hv1a. This epitope provides a structural template for rational design of chemical insecticides that selectively target insect Ca-v channels
N-glycans of Human Protein C Inhibitor: Tissue-Specific Expression and Function
Protein C inhibitor (PCI) is a serpin type of serine protease inhibitor that is found in many tissues and fluids in human, including blood plasma, seminal plasma and urine. This inhibitor displays an unusually broad protease specificity compared with other serpins. Previous studies have shown that the N-glycan(s) and the NH2-terminus affect some blood-related functions of PCI. In this study, we have for the first time determined the N-glycan profile of seminal plasma PCI, by mass spectrometry. The N-glycan structures differed markedly compared with those of both blood-derived and urinary PCI, providing evidence that the N-glycans of PCI are expressed in a tissue-specific manner. The most abundant structure (m/z 2592.9) had a composition of Fuc3Hex5HexNAc4, consistent with a core fucosylated bi-antennary glycan with terminal Lewisx. A major serine protease in semen, prostate specific antigen (PSA), was used to evaluate the effects of N-glycans and the NH2-terminus on a PCI function related to the reproductive tract. Second-order rate constants for PSA inhibition by PCI were 4.3±0.2 and 4.1±0.5 M−1s−1 for the natural full-length PCI and a form lacking six amino acids at the NH2-terminus, respectively, whereas these constants were 4.8±0.1 and 29±7 M−1s−1 for the corresponding PNGase F-treated forms. The 7–8-fold higher rate constants obtained when both the N-glycans and the NH2-terminus had been removed suggest that these structures jointly affect the rate of PSA inhibition, presumably by together hindering conformational changes of PCI required to bind to the catalytic pocket of PSA
The littoral sea cucumber (Echinodermata: Holothuroidea) fauna of Guam re-assessed – a diversity curve that still does not asymptote
The Micronesian island of Guam has been an important site for the study of tropical holothuroid taxonomy for almost 200 years. Despite such substantial attention by both expeditions and resident taxonomists, new records are being regularly added to the fauna demonstrating the challenge of documenting the biota of even a small hyper-diverse area. Guam is the type locality of species described by Quoy & Gaimard (1833) and Brandt (1835). A survey of the sea cucumber fauna by Rowe & Doty (1977) led to one of the most used guides for the identification of tropical Pacific sea cucumbers because of the color illustrations of living animals it presented. Focus on echinoderms including holothuroids continued with numerous new records added in the following decades. Paulay (2003) summarized the fauna last, recording 46 species, including 9 new records. At this stage the fauna was thought to be well documented. A week-long workshop on holothuroid systematics sponsered by the NSF PEET project in 2010 included a substantial field work component, sampling both during the day and night, with snorkeling and SCUBA, across a variety of habitats, yielding more than 40 species. 10 of these proved new records for Guam; two proved new to science. Further sampling by Kerr’s lab since the workshop has added two additional species. The holothuroid fauna of Guam thus now comprises 58 species that belong to 17 genera and 7 families. This contribution presents them as an illustrated and briefly annotated checklist
HAMLET Binding to α-Actinin Facilitates Tumor Cell Detachment
Cell adhesion is tightly regulated by specific molecular interactions and detachment from the extracellular matrix modifies proliferation and survival. HAMLET (Human Alpha-lactalbumin Made LEthal to Tumor cells) is a protein-lipid complex with tumoricidal activity that also triggers tumor cell detachment in vitro and in vivo, suggesting that molecular interactions defining detachment are perturbed in cancer cells. To identify such interactions, cell membrane extracts were used in Far-western blots and HAMLET was shown to bind α-actinins; major F-actin cross-linking proteins and focal adhesion constituents. Synthetic peptide mapping revealed that HAMLET binds to the N-terminal actin-binding domain as well as the integrin-binding domain of α-actinin-4. By co-immunoprecipitation of extracts from HAMLET-treated cancer cells, an interaction with α-actinin-1 and -4 was observed. Inhibition of α-actinin-1 and α-actinin-4 expression by siRNA transfection increased detachment, while α-actinin-4-GFP over-expression significantly delayed rounding up and detachment of tumor cells in response to HAMLET. In response to HAMLET, adherent tumor cells rounded up and detached, suggesting a loss of the actin cytoskeletal organization. These changes were accompanied by a reduction in β1 integrin staining and a decrease in FAK and ERK1/2 phosphorylation, consistent with a disruption of integrin-dependent cell adhesion signaling. Detachment per se did not increase cell death during the 22 hour experimental period, regardless of α-actinin-4 and α-actinin-1 expression levels but adherent cells with low α-actinin levels showed increased death in response to HAMLET. The results suggest that the interaction between HAMLET and α-actinins promotes tumor cell detachment. As α-actinins also associate with signaling molecules, cytoplasmic domains of transmembrane receptors and ion channels, additional α-actinin-dependent mechanisms are discussed
Impact of Ocean Warming and Ocean Acidification on Larval Development and Calcification in the Sea Urchin Tripneustes gratilla
Background: As the oceans simultaneously warm, acidify and increase in P-CO2, prospects for marine biota are of concern. Calcifying species may find it difficult to produce their skeleton because ocean acidification decreases calcium carbonate saturation and accompanying hypercapnia suppresses metabolism. However, this may be buffered by enhanced growth and metabolism due to warming.Methodology/Principal Findings: We examined the interactive effects of near-future ocean warming and increased acidification/P-CO2 on larval development in the tropical sea urchin Tripneustes gratilla. Larvae were reared in multifactorial experiments in flow-through conditions in all combinations of three temperature and three pH/P-CO2 treatments. Experiments were placed in the setting of projected near future conditions for SE Australia, a global change hot spot. Increased acidity/P-CO2 and decreased carbonate mineral saturation significantly reduced larval growth resulting in decreased skeletal length. Increased temperature (+3 degrees C) stimulated growth, producing significantly bigger larvae across all pH/P-CO2 treatments up to a thermal threshold (+6 degrees C). Increased acidity (-0.3-0.5 pH units) and hypercapnia significantly reduced larval calcification. A +3 degrees C warming diminished the negative effects of acidification and hypercapnia on larval growth.Conclusions and Significance: This study of the effects of ocean warming and CO2 driven acidification on development and calcification of marine invertebrate larvae reared in experimental conditions from the outset of development (fertilization) shows the positive and negative effects of these stressors. In simultaneous exposure to stressors the dwarfing effects of acidification were dominant. Reduction in size of sea urchin larvae in a high P-CO2 ocean would likely impair their performance with negative consequent effects for benthic adult populations
The Indian cobra reference genome and transcriptome enables comprehensive identification of venom toxins
Snakebite envenoming is a serious and neglected tropical disease that kills ~100,000 people annually. High-quality, genome-enabled comprehensive characterization of toxin genes will facilitate development of effective humanized recombinant antivenom. We report a de novo near-chromosomal genome assembly of Naja naja, the Indian cobra, a highly venomous, medically important snake. Our assembly has a scaffold N50 of 223.35 Mb, with 19 scaffolds containing 95% of the genome. Of the 23,248 predicted protein-coding genes, 12,346 venom-gland-expressed genes constitute the \u27venom-ome\u27 and this included 139 genes from 33 toxin families. Among the 139 toxin genes were 19 \u27venom-ome-specific toxins\u27 (VSTs) that showed venom-gland-specific expression, and these probably encode the minimal core venom effector proteins. Synthetic venom reconstituted through recombinant VST expression will aid in the rapid development of safe and effective synthetic antivenom. Additionally, our genome could serve as a reference for snake genomes, support evolutionary studies and enable venom-driven drug discovery
HE-LHC: The High-Energy Large Hadron Collider – Future Circular Collider Conceptual Design Report Volume 4
In response to the 2013 Update of the European Strategy for Particle Physics (EPPSU), the Future Circular Collider (FCC) study was launched as a world-wide international collaboration hosted by CERN. The FCC study covered an energy-frontier hadron collider (FCC-hh), a highest-luminosity high-energy lepton collider (FCC-ee), the corresponding 100 km tunnel infrastructure, as well as the physics opportunities of these two colliders, and a high-energy LHC, based on FCC-hh technology. This document constitutes the third volume of the FCC Conceptual Design Report, devoted to the hadron collider FCC-hh. It summarizes the FCC-hh physics discovery opportunities, presents the FCC-hh accelerator design, performance reach, and staged operation plan, discusses the underlying technologies, the civil engineering and technical infrastructure, and also sketches a possible implementation. Combining ingredients from the Large Hadron Collider (LHC), the high-luminosity LHC upgrade and adding novel technologies and approaches, the FCC-hh design aims at significantly extending the energy frontier to 100 TeV. Its unprecedented centre-of-mass collision energy will make the FCC-hh a unique instrument to explore physics beyond the Standard Model, offering great direct sensitivity to new physics and discoveries
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