Academic literature on the topic 'Cone snails'
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Journal articles on the topic "Cone snails"
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Ebou, Anicet, Dominique Koua, Audrey Addablah, Solange Kakou-Ngazoa, and Sébastien Dutertre. "Combined Proteotranscriptomic-Based Strategy to Discover Novel Antimicrobial Peptides from Cone Snails." Biomedicines 9, no. 4 (March 29, 2021): 344. http://dx.doi.org/10.3390/biomedicines9040344.
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Despite their impressive diversity and already broad therapeutic applications, cone snail venoms have received less attention as a natural source in the investigation of antimicrobial peptides than other venomous animals such as scorpions, spiders, or snakes. Cone snails are among the largest genera (Conus sp.) of marine invertebrates, with more than seven hundred species described to date. These predatory mollusks use their sophisticated venom apparatus to capture prey or defend themselves. In-depth studies of these venoms have unraveled many biologically active peptides with pharmacological properties of interest in the field of pain management, the treatment of epilepsy, neurodegenerative diseases, and cardiac ischemia. Considering sequencing efficiency and affordability, cone snail venom gland transcriptome analyses could allow the discovery of new, promising antimicrobial peptides. We first present here the need for novel compounds like antimicrobial peptides as a viable alternative to conventional antibiotics. Secondly, we review the current knowledge on cone snails as a source of antimicrobial peptides. Then, we present the current state of the art in analytical methods applied to crude or milked venom followed by how antibacterial activity assay can be implemented for fostering cone snail antimicrobial peptides studies. We also propose a new innovative profile Hidden Markov model-based approach to annotate full venom gland transcriptomes and speed up the discovery of potentially active peptides from cone snails.
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Peraud, Olivier, Jason S. Biggs, Ronald W. Hughen, Alan R. Light, Gisela P. Concepcion, Baldomero M. Olivera, and Eric W. Schmidt. "Microhabitats within Venomous Cone Snails Contain Diverse Actinobacteria." Applied and Environmental Microbiology 75, no. 21 (September 11, 2009): 6820–26. http://dx.doi.org/10.1128/aem.01238-09.
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ABSTRACT Actinomycetes can be symbionts in diverse organisms, including both plants and animals. Some actinomycetes benefit their host by producing small molecule secondary metabolites; the resulting symbioses are often developmentally complex. Actinomycetes associated with three cone snails were studied. Cone snails are venomous tropical marine gastropods which have been extensively examined because of their production of peptide-based neurological toxins, but no microbiological studies have been reported on these organisms. A microhabitat approach was used in which dissected tissue from each snail was treated as an individual sample in order to explore bacteria in the tissues separately. Our results revealed a diverse, novel, and highly culturable cone snail-associated actinomycete community, with some isolates showing promising bioactivity in a neurological assay. This suggests that cone snails may represent an underexplored reservoir of novel actinomycetes of potential interest for drug discovery.
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Safavi-Hemami, Helena, Joanna Gajewiak, Santhosh Karanth, Samuel D. Robinson, Beatrix Ueberheide, Adam D. Douglass, Amnon Schlegel, et al. "Specialized insulin is used for chemical warfare by fish-hunting cone snails." Proceedings of the National Academy of Sciences 112, no. 6 (January 20, 2015): 1743–48. http://dx.doi.org/10.1073/pnas.1423857112.
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More than 100 species of venomous cone snails (genus Conus) are highly effective predators of fish. The vast majority of venom components identified and functionally characterized to date are neurotoxins specifically targeted to receptors, ion channels, and transporters in the nervous system of prey, predators, or competitors. Here we describe a venom component targeting energy metabolism, a radically different mechanism. Two fish-hunting cone snails, Conus geographus and Conus tulipa, have evolved specialized insulins that are expressed as major components of their venoms. These insulins are distinctive in having much greater similarity to fish insulins than to the molluscan hormone and are unique in that posttranslational modifications characteristic of conotoxins (hydroxyproline, γ-carboxyglutamate) are present. When injected into fish, the venom insulin elicits hypoglycemic shock, a condition characterized by dangerously low blood glucose. Our evidence suggests that insulin is specifically used as a weapon for prey capture by a subset of fish-hunting cone snails that use a net strategy to capture prey. Insulin appears to be a component of the nirvana cabal, a toxin combination in these venoms that is released into the water to disorient schools of small fish, making them easier to engulf with the snail’s distended false mouth, which functions as a net. If an entire school of fish simultaneously experiences hypoglycemic shock, this should directly facilitate capture by the predatory snail.
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Wang, Hao, Xiaopeng Zhu, Yuepeng Liu, Sulan Luo, and Dongting Zhangsun. "Mitogenome Characterization of Four Conus Species and Comparative Analysis." International Journal of Molecular Sciences 24, no. 11 (May 28, 2023): 9411. http://dx.doi.org/10.3390/ijms24119411.
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Cone snails, as a type of marine organism, have rich species diversity. Traditionally, classifications of cone snails were based mostly on radula, shell, and anatomical characters. Because of these phenotypic features’ high population variability and propensity for local adaptation and convergence, identifying species can be difficult and occasionally inaccurate. In addition, mitochondrial genomes contain high phylogenetic information, so complete mitogenomes have been increasingly employed for inferring molecular phylogeny. To enrich the mitogenomic database of cone snails (Caenogastropoda: Conidae), mitogenomes of four Conus species, i.e., C. imperialis (15,505 bp), C. literatus (15,569 bp), C. virgo (15,594 bp), and C. marmoreus (15,579 bp), were characterized and compared. All 4 of these mitogenomes included 13 protein-coding genes, 2 ribosomal RNA genes, 22 tRNA genes, and non-coding regions. All the Protein Codon Genes (PCGs) of both newly sequenced mitogenomes used TAA or TAG as a terminal codon. Most PCGs used conventional start codon ATG, but an alternative initiation codon GTG was detected in a gene (NADH dehydrogenase subunit 4 (nad4)) of C. imperialis. In addition, the phylogenetic relationships were reconstructed among 20 Conus species on the basis of PCGs, COX1, and the complete mitogenome using both Bayesian Inference (BI) and Maximum Likelihood (ML). The phylogenetic results supported that C. litteratus, C. quercinus, and C. virgo were clustered together as a sister group (PP = 1, BS = 99), but they did not support the phylogenetic relation of C. imperialis and C. tribblei (PP = 0.79, BS = 50). In addition, our study established that PCGs and complete mitogenome are the two useful markers for phylogenetic inference of Conus species. These results enriched the data of the cone snail’s mitochondrion in the South China Sea and provided a reliable basis for the interpretation of the phylogenetic relationship of the cone snail based on the mitochondrial genome.
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Chivian, E. "The Threat to Cone Snails." Science 302, no. 5644 (October 17, 2003): 391b—391. http://dx.doi.org/10.1126/science.302.5644.391b.
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Park, Youmie. "Mining Invertebrate Natural Products for Future Therapeutic Treasure." Natural Product Communications 6, no. 9 (September 2011): 1934578X1100600. http://dx.doi.org/10.1177/1934578x1100600944.
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This review focuses on biologically active entities from invertebrate sources, especially snails. The reader will encounter several categories of compounds from snails including glycosaminoglycans, peptides, proteins (glycoproteins), and enzymes which possess diverse biological activities. Among glycosaminoglycans, acharan sulfate which was isolated from a giant African snail Acahtina fulica is reviewed extensively. Conotoxins which are also called conopeptides are unique peptide mixtures from marine cone snail. Conotoxins are secreted to capture its prey, and currently have the potential to be highly effective drug candidates. One of the conotoxins is now in the market as a pain killer. Proteins as well as glycoproteins in the snail are known to be involved in the host defense process from an attack of diverse pathogens. Carbohydrate-degrading enzymes characterized and purified in snails are introduced to give an insight into the applicability in glycobiology research such as synthesis and structure characterization of glycoconjugates. It seems that simple snails produce very complicated biological compounds which could be an invaluable source in future therapeutics as well as research areas in natural medicine.
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Jin, Ai-Hua, Mathilde R. Israel, Marco C. Inserra, Jennifer J. Smith, Richard J. Lewis, Paul F. Alewood, Irina Vetter, and Sébastien Dutertre. "δ-Conotoxin SuVIA suggests an evolutionary link between ancestral predator defence and the origin of fish-hunting behaviour in carnivorous cone snails." Proceedings of the Royal Society B: Biological Sciences 282, no. 1811 (July 22, 2015): 20150817. http://dx.doi.org/10.1098/rspb.2015.0817.
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Some venomous cone snails feed on small fishes using an immobilizing combination of synergistic venom peptides that target K v and Na v channels. As part of this envenomation strategy, δ-conotoxins are potent ichtyotoxins that enhance Na v channel function. δ-Conotoxins belong to an ancient and widely distributed gene superfamily, but any evolutionary link from ancestral worm-eating cone snails to modern piscivorous species has not been elucidated. Here, we report the discovery of SuVIA, a potent vertebrate-active δ-conotoxin characterized from a vermivorous cone snail ( Conus suturatus ). SuVIA is equipotent at hNa V 1.3, hNa V 1.4 and hNa V 1.6 with EC 50 s in the low nanomolar range. SuVIA also increased peak hNa V 1.7 current by approximately 75% and shifted the voltage-dependence of activation to more hyperpolarized potentials from –15 mV to –25 mV, with little effect on the voltage-dependence of inactivation. Interestingly, the proximal venom gland expression and pain-inducing effect of SuVIA in mammals suggest that δ-conotoxins in vermivorous cone snails play a defensive role against higher order vertebrates. We propose that δ-conotoxins originally evolved in ancestral vermivorous cones to defend against larger predators including fishes have been repurposed to facilitate a shift to piscivorous behaviour, suggesting an unexpected underlying mechanism for this remarkable evolutionary transition.
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Joo, Soyoun, Sunghwan Jung, Sungyon Lee, Robert H. Cowie, and Daisuke Takagi. "Freshwater snail feeding: lubrication-based particle collection on the water surface." Journal of The Royal Society Interface 17, no. 165 (April 2020): 20200139. http://dx.doi.org/10.1098/rsif.2020.0139.
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The means by which aquatic animals such as freshwater snails collect food particles distributed on the water surface are of great interest for understanding life at the air–water interface. The apple snail Pomacea canaliculata stabilizes itself just below the air–water interface and manipulates its foot such that it forms a cone-shaped funnel into which an inhalant current is generated, thereby drawing food particles into the funnel to be ingested. We measured the velocity of this feeding current and tracked the trajectories of food particles around and on the snail. Our experiments indicated that the particles were collected via the free surface flow generated by the snail’s undulating foot. The findings were interpreted using a simple model based on lubrication theory, which considered several plausible mechanisms depending on the relative importance of hydrostatic pressure, capillary action and rhythmic surface undulation.
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Morales Duque, Harry, Simoni Campos Dias, and Octávio Luiz Franco. "Structural and Functional Analyses of Cone Snail Toxins." Marine Drugs 17, no. 6 (June 21, 2019): 370. http://dx.doi.org/10.3390/md17060370.
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Cone snails are marine gastropod mollusks with one of the most powerful venoms in nature. The toxins, named conotoxins, must act quickly on the cone snails´ prey due to the fact that snails are extremely slow, reducing their hunting capability. Therefore, the characteristics of conotoxins have become the object of investigation, and as a result medicines have been developed or are in the trialing process. Conotoxins interact with transmembrane proteins, showing specificity and potency. They target ion channels and ionotropic receptors with greater regularity, and when interaction occurs, there is immediate physiological decompensation. In this review we aimed to evaluate the structural features of conotoxins and the relationship with their target types.
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O’Brien, Henrik, Shingo Kanemura, Masaki Okumura, Robert Baskin, Pradip Bandyopadhyay, Baldomero Olivera, Lars Ellgaard, Kenji Inaba, and Helena Safavi-Hemami. "Ero1-Mediated Reoxidation of Protein Disulfide Isomerase Accelerates the Folding of Cone Snail Toxins." International Journal of Molecular Sciences 19, no. 11 (October 31, 2018): 3418. http://dx.doi.org/10.3390/ijms19113418.
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Disulfide-rich peptides are highly abundant in nature and their study has provided fascinating insight into protein folding, structure and function. Venomous cone snails belong to a group of organisms that express one of the largest sets of disulfide-rich peptides (conotoxins) found in nature. The diversity of structural scaffolds found for conotoxins suggests that specialized molecular adaptations have evolved to ensure their efficient folding and secretion. We recently showed that canonical protein disulfide isomerase (PDI) and a conotoxin-specific PDI (csPDI) are ubiquitously expressed in the venom gland of cone snails and play a major role in conotoxin folding. Here, we identify cone snail endoplasmic reticulum oxidoreductin-1 (Conus Ero1) and investigate its role in the oxidative folding of conotoxins through reoxidation of cone snail PDI and csPDI. We show that Conus Ero1 preferentially reoxidizes PDI over csPDI, suggesting that the reoxidation of csPDI may rely on an Ero1-independent molecular pathway. Despite the preferential reoxidation of PDI over csPDI, the combinatorial effect of Ero1 and csPDI provides higher folding yields than Ero1 and PDI. We further demonstrate that the highest in vitro folding rates of two model conotoxins are achieved when all three enzymes are present, indicating that these enzymes may act synergistically. Our findings provide new insight into the generation of one of the most diverse classes of disulfide-rich peptides and may improve current in vitro approaches for the production of venom peptides for pharmacological studies.
Dissertations / Theses on the topic "Cone snails"
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Peters, Howard. "Cone snails : a significant biomedical resource at risk." Thesis, University of York, 2013. http://etheses.whiterose.ac.uk/5101/.
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Gastropod molluscs of the genus Conus (cone snails) occur throughout the world’s tropical coastal waters where they capture their prey of fish, molluscs or worms using a complex battery of neurotoxins. Although these toxins are of major importance to biomedical science, the conservation status of Conus has been largely ignored. I assessed 632 species of Conus to the standards of IUCN Red List of Threatened Species. This revealed 10.6% of species globally are either threatened or near threatened with extinction, with a further 13.8% data deficient but with indicators that suggest substantial cause for concern. Hotspots of endemism, particularly along the Eastern Atlantic found 42.9% of 98 species there at risk. This includes Cape Verde where 53 of 56 species are endemic and mostly restricted to single islands, and where all three critically endangered and four of eleven globally endangered species occur. The rapid transition of the Cape Verdean economy from services to tourism was found to have placed many Conus species at risk from habitat disturbance and marine pollution. Although the Red List yields valuable data, it is primarily focussed on species nearing extinction. However, many wide-ranging species, exposed to considerable anthropogenic impacts, may, through remoteness and/or depth, remain unnoticed and unrecorded for years, invisible to the Red List as their populations decline. To identify such species I explored the overlap of Conus with biogeographic data of human impacts and future threats from ocean acidification and thermal stress. This revealed a further 67 species occurring in high impact zones deserving further status consideration, and pinpointed regions with high concentrations of endemic taxa under potential threat. This reinforced the benefits of approaching threat assessment from a holistic standpoint in addition to the forensic scrutiny offered by the Red List, allowing proactive conservation management to complement its traditional reactive role.
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Bullard, Elizabeth. "Compositional variability of Pleistocene land snail assemblages preserved in a cinder cone volcano from Tenerife, Canary Islands." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1470744125.
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Ferreira, Débora Rezende. "Alterações físico-químicas do óleo de palma na pré-fritura contínua de produtos cárneos empanados de frango - tipo "snacks"." Universidade Estadual de Londrina. Centro de Ciências Agrárias. Programa de Pós-Graduação em Ciência de Alimentos, 2010. http://www.bibliotecadigital.uel.br/document/?code=vtls000163014.
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A falta de tempo para o preparo de alimento tem provocado um aumento no consumo de alimentos fritos que constituem uma alternativa rápida de preparo que promove propriedades sensoriais altamente apreciadas por consumidores. A fritura contínua é utilizada pelo mercado industrial para o preparo de pré-frituras. O óleo de palma possui alta estabilidade oxidativa por possuir quantidades de ácidos graxos saturados e insaturados quase equivalentes. As alterações físico-químicas do óleo de palma durante a pré-fritura contínua de produtos cárneos empanados foram avaliadas através de medidas de degradação de índice de acidez e refração, compostos polares, viscosidade, cor e absortividade (232 e 268nm) em 238 amostras coletadas ao longo de 28 dias de produção. Os dados foram submetidos a ANOVA, teste de Tukey, Análise de Componentes Principais (ACP) e de regressão linear (cinética de 1°ordem). Ao final do período avaliado o óleo apresentou valores máximos de 0,64% de índice de acidez em ácido oléico, 1,4680 de índice de refração, 17,3% de compostos polares, 59,5 cp de viscosidade a 20 rpm, 3,558 e 1,158 de absortividade a 232 e 268nm respectivamente. Houve aumento do escurecimento do óleo ao longo do tempo. O primeiro componente principal (57% de explicação) separou as amostras coletadas em diferentes semanas do experimento, sendo que as amostras à direita do CP1 foram as coletadas na primeira e segunda semana, e as da esquerda coletadas na terceira e quarta semana. Os vetores L* e viscosidade 20 rpm foram inversamente correlacionados indicando que quanto menor o L* maior é a viscosidade. Os vértices do triângulo que representaram os dados do último dia de produção ficaram muito próximos indicando que houve repetibilidade da avaliação. As amostras do primeiro dia do experimento ficaram localizadas à direita do CP1 e abaixo no CP2 (21% de explicação), apresentando baixos valores relacionados a índice de acidez e refração e compostos polares. Apesar das diferenças terem sido encontradas nas respostas dos parâmetros avaliados ao longo do tempo de fritura e em diferentes turnos, o óleo não apresentou após 28 dias de pré-fritura, em nenhuma análise, valores superiores aos limites recomendados por alguns países para o descarte dos mesmos, sugerindo que as condições estabelecidas no processo são seguras e indicam que o óleo é adequado para ser utilizado como meio de fritura sob as condições do experimento. A medida de degradação de compostos polares foi a que melhor se ajustou ao modelo cinético proposto, podendo ser indicada como um método eficaz para o monitoramento do óleo de fritura contínua de produtos cárneos empanados, além do método utilizado para a determinação ser rápido e prático para ser realizado numa indústria.The lack of time for the preparation of food has caused an increase in consumption of fried foods that are a rapid alternative of preparation that promotes sensory properties highly appreciated by consumers. The continuous frying method is used by the industrial market for pre frying procedures. Palm oil has high oxidative stability by having almost equivalent amounts of saturated and unsaturated fatty acids. The physical and chemical properties of palm oil during the continuous pre-fried breaded meat products were assessed by acid values and refraction, indexes polar compounds, contents viscosity, color and absorptivity (232 and 268nm) in 238 samples collected over 28 days of production. The data were analyzed by ANOVA, Tukey, Principal Component Analysis and linear regression analysis (1st order kinetics). At the end of the study period, the oil showed maximum values of 0,64% acid value in oleic acid, 1,4680 of refractive index, 17,3% of polar compounds, 59.5 cp viscosity at 20 rpm, 3,558 and 1,158 of absorptivity at 232 and 268nm respectively. There was increased darkening of oil over time. The first principal component (57.33% of explanation) separated samples collected at different weeks of the experiment, while the samples to the right of CP1 were collected in the first and second weeks, and the samples to the left were collected in the third and fourth weeks. The vectors L* and viscosity at 20 rpm were inversely correlated indicating that the lower the L* the greater the viscosity. The vertices of the triangle representing the data of the last day of production were very close indicating that there was repeatability of the assessment. Samples from the first day of experiment were located on the right in the CP1 and down in the CP2 (21.33% of explanation), showing low values associated with the analysis of acidity and refractive index and polar compounds. Despite differences found in the responses of these parameters over the frying time and in different shifts, the oil did not show after 28 days of pre frying in any analysis, values higher than the limits recommended by some countries to disposal, suggesting that the conditions during the process were safe and indicated that the oil is suitable for use as a frying medium under the experimental conditions. The extent of degradation of polar compounds was the best index to the proposed kinetic model and it can be recommended as an effective method for monitoring continuous frying oil in breaded meat products besides, the method used to the resolution is rapid and convenient to be performed in industry.
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Neves, Jorge do Livramento Brito. "Analysis of Venom in Cape verde Cone Snails." Doctoral thesis, 2016. https://repositorio-aberto.up.pt/handle/10216/93082.
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Neves, Jorge do Livramento Brito. "Analysis of Venom in Cape verde Cone Snails." Tese, 2016. https://repositorio-aberto.up.pt/handle/10216/93082.
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Kumar, G. Senthil. "Solution NMR Studies Of Peptide Toxins From Cone Snails And Scorpion." Thesis, 2008. http://hdl.handle.net/2005/862.
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Major constituents of the venom of various animals are peptidogenic in nature. Marine snails belonging to the species Conus are venomous predators that use small, structurally constrained peptides present in their venom for prey capture and defense. It is known that ~500 Conus species are present in nature and the venom of each of these Conus species is a complex mixture of nearly 100 peptides accounting for > 50,000 peptides with little overlap among the different species. The peptides isolated from the venom of Conus species are commonly known as conotoxins or conopeptides. Some of the common targets of these peptides include the different ion channels like Na+, K+, and Ca2+, and receptor subtypes such as nicotinic acetylcholine and NMDA receptors. The ion channels and receptor subtypes were targeted by conopeptides with high degree of specificity and selectivity. The structural information on the peptides from cone snails can prove to be a valuable starting tool for the understanding of the function of different ion channels and hence in the design of neuropharmacologically active drugs. Conotoxins are disulfide-rich peptides and the number of disulfide generally ranges from two to five. Based on the arrangement of cysteines in their primary sequence, they are classified into different superfamilies. The signal sequences of the precursors belonging to a particular superfamily are highly conserved and hence the members within the same family have, in common, the unique disulfide arrangement and pharmacological activity. Conotoxins are classified into eleven superfamilies till date. In order to understand the underlying the principles involved in the action of these peptides on different ion channels, one needs to know the three-dimensional structures which, in potential, will help in the identification of the pharmacophores responsible for the observed pharmacological activity. With the aim of studying the structure-activity relationships found among the conotoxins, we have initiated a study on the peptides isolated from the marine snails found in the Indian coastal waters. This thesis is focused in the structural studies of the peptide toxins from marine cone snails and a terrestrial scorpion. The tool used for the structural studies of these peptide toxins is Nuclear Magnetic Resonance Spectroscopy.
Chapter 1 provides an overview of the peptide toxins found among various animal species with more emphasis on conotoxins and scorpion toxins. In addition, the rationale behind the present study has also been explained.
Chapter 2 describes the structure determination of two conopeptides isolated from Conus amadis, δ-Am2766 and Am2735, which are active on mammalian sodium channels. The structural aspects and comparison with other known conopeptides belonging to the same superfamily as that of these two peptides have also been described.
Solution NMR studies of Ar1446 and Ar1248, two conopeptides isolated from the species Conus araneosus have also been studied using Homonuclear NMR methods. Ar1446 is a three disulfide-bonded peptide. Our studies have revealed that this peptide has a novel disulfide connectivity not previously observed in the M superfamily or any other superfamily of conotoxins. The structural features of Ar1446 will be described along with the NMR studies on two-disulfide bonded peptide, Ar1248, belonging to the A-superfamily of conotoxins.
The main problem faced in the kind of study of peptides isolated from natural sources is the amount that can be isolated and purified to homogeneity. In order to obtain large quantities of peptides, we have successfully used Cytochrome b5 as fusion host to clone, over express and purify these peptides using recombinant methods. The use of recombinant methods has aided in the preparation of isotopically enriched peptides. The use of cyt b5 as fusion host for the large scale production of some of the peptides from Indian marine snails is described in Chapter 4.
A novel pharmacologically active linear peptide, Mo1659 isolated from Conus monile, have been studied using Heteronuclear NMR methods. This peptide was cloned, over expressed and purified using Cytochrome b5 as a fusion host. Another linear peptide, Mo1692 (also from Conus monile), has been prepared using the same method and was studied using Homonuclear NMR methods. Both these peptides were liberated from the fusion host using cyanogen bromide cleavage and were subsequently purified using RP-HPLC. The results of the biosynthetic preparation and NMR studies of these two peptides have been described in Chapter 5.
Chapter 6 describes the solution structure determination of a novel scorpion toxin characterized in the venom of the Indian red scorpion Buthus tamulus. The cloning, over expression, folding and purification of BTK-2 is described here. The structure and the function of this recombinantly produced BTK-2 will also be described.
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Ribeiro, Sónia Raquel Gomes. "Characterization of natural products in cone snails from the Cabo Verde archipelago." Master's thesis, 2021. https://hdl.handle.net/10216/137958.
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Wei, Chen-Po, and 陳柏瑋. "Application of PCR-RFLP Technique for Species Identification and Hemotoxicity of Toxin in Cone Snails." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/99098790921278774407.
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碩士國立臺灣海洋大學
食品科學系
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Conus is a kind of sea snail which has sting toxin and diverse patterns. They anesthetize the preys through venom injecting by their harpoon-like radular teeth. Because of their specific characteristics, they can be alive in perilous environment over a long period of time. Many studies demonstrated that conotoxin (CTX) has acute neurotoxicity but it was confirmed that CTX also has hemolytic activity. In spite of acute neurotoxicity, conotoxin still has the potency as a therapeutic medical agent on lenitive treatment. The purpose of this study was to authenticate Conus species and analyze their hemolytic activity. There are twenty-six species of Conus selected to identify species by using PCR (polymerase chain reaction) technique with direct sequencing. Furthermore, PCR-RFLP (polymerase chain reaction – fragment length polymorphism) technology was used to develop rapid and precise method for identifying the ten Conus species in four groups. The results indicated that utilizing the ability of four restriction enzymes (DraI, SspI, HindIII and EcoRV) with specific cutting site, the digestion patterns were able to distinguish ten Conus species. In addition, this is the first demonstration in Taiwan that venom derived from Conus betulinus has hemolytic activity, and the venom was affected by some chemical and physical factors such as ion, pH and temperature. The hemolytic activity was reduced when the concentration of Zn2+, Cu2+ and Fe2+ increased. The highest hemolytic activity of venom was at pH 7 but sharply reduced its activity at pH being lower than 3. Furthermore, hemolytic activity was thermo-sensitive and was dramatically reduced over 40℃. These results indicated that PCR with direct sequencing and PCR-RFLP are valuable tools for identification of Conus species. The hemolytic activity was affected by ionic concentrations, pH and temperature.
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Mondal, Sukanta. "Contributions To Venominformatics : Sequence-Structure-Function Studies Of Toxins From Marine Cone Snails. Application Of Order-Statistics Filters For Detecting Membrane-Spanning Helices." Thesis, 2007. http://hdl.handle.net/2005/566.
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Venomous animals have evolved a vast array of peptide toxins for prey capture and defense. Nature has evolved the venoms into a huge library of active molecules with high selectivity and affinity, which could be explored as therapeutics or serve as a template for drug design. The individual components of venom i.e. toxins are used in ion channel and receptor studies, drug discovery, and formulation of insecticides. ‘Venominformatics is a systematic bioinformatics approach in which classified, consolidated and cleaned venom data are stored into repositories and integrated with advanced bioinformatics tools and computational biology for the analysis of structure and function of toxins.’
Conus peptides (conopeptides), the main components of Conus venom, represent a unique arsenal of neuropharmacologically active molecules that have been evolutionarily tailored to afford unprecedented and exquisite selectivity for a wide variety of ion-channel subtypes and neuronal receptors. Ziconotide (ω-conotoxin MVIIa from Conus magus (Magician's cone snail)), is proven as an intrathecally administered N-type calcium channel antagonist for the treatment of chronic pain (U.S. Food and Drug Administration. Center for Drug Evaluation and Research) attesting to the pharmaceutical importance of Conus peptides. From the point of view of protein sequence and structure analysis, conopeptides can serve as attractive systems for the studies in sequence comparison, pattern extraction, structure–function correlations, protein–protein interactions and evolutionary analysis. Despite their importance and extensive experimental investigations on them, they have been hardly explored through in silico methods. The present thesis is perhaps the first attempt at deploying a multi-pronged bioinformatics approaches for studies in the burgeoning field of conopeptides.
In the process of sequence-structure-function studies of conopeptides, we have created several sequence patterns of different conopeptide families and these have been accepted for inclusion in international databases such as PROSITE, the first pattern database to have been developed (http://www.expasy.org/prosite) and INTERPRO (http://www.ebi.ac.uk/interpro). More importantly, we have carried out extensive literature survey on the peptides for which we have defined the patterns to create PROSITE compatible documentation files (PDOC6004, PDOC60025 and PDOC60027). We have also created a series of sequence patterns and associated documentation filesof pharmaceutically promising peptides from plants and venomous animals (including O-conotoxin and P-conotoxin superfamily members) with knottin scaffold. Knottins provide appealing scaffolds for protein engineering and drug design due to their small size, high structural stability, strong sequence tolerance and easy access to chemical synthesis. The sequence patterns and associated documentation files created by us should be useful in protein family classification and functional annotation. Even though patterns might be useful at the family level, they may not always be adequate at the superfamily level due to hypervariability of mature toxins. In order to overcome this problem, we have demonstrated the applicationos of multi-class support vector machines (MC-SVMs) for the successful in silico classification of the mature conotoxins into their superfamilies.
TheI- and J-conotoxin-superfamily members were analyzed in greater detail. On the basis of in silico analysis, we have divided the 28 entries previously grouped as I-conotoxin superfamily in UniProtKB/Swiss-Prot (release 49.0) into I1 and I2 superfamilies inview of their having two different types of signal peptides and exhibiting distinct functions. A comparative study of the theoretically modeled structure of ViTx from Conus virgo, a typical member of I2-conotoxin superfamily, reveals the crucial role of C-terminal region of ViTx in blocking therapeutically important voltage-gated potassium channels. Putative complexes created by us of very recently characterized J-superfamily conotoxin p11-4a with Kv1.6 suggest that the peptide interacts with negatively charged extracellular loops and pore-mouth of the potassium channel and blocks the channel by covering the pore as a lid, akin to previously proposed blocking mechanism of kM-conotoxin RIIIK from Conus radiatus to Tsha1 potassium channel. This finding provides a pointer to experimental work to validate the observations made here. Based on differences in the number and distribution of the positively charged residues in other conopeptides from the J-superfamily, we hypothesize different selectivity profile against subtypes of the potassium channels for these conopeptides.
Furthermore, the present thesis reports the application of order-statistic filters and hydrophobicity profiles for predicting the location of membrane-spanning helices. The
Proposed method is in particular effective for the class of helical membrane proteins, namely the therapeutically important voltage-gated ion channels, which are natural targets of several conotoxins. Our suggested ab initio approach is comparatively better than other spatial filters, confirming to the efficacy of including the concept of order or ranking information for prediction of TM helicdes. Such approaches should be of value for improved prediction performance including in large-scale applications.
In addition, anlaysis has been carried out of the role of context in the relationship between form and function for the true PDB hits of some nonCys-rich PROSITE patterns.
We have found specific examples of true hits of some PROSITE patterns displaying structural plasticity by assuming significantly different local conformation, depending upon the context. The work was carried out as a part of the research interest in our group in studying structural and other features of protein sequence patterns.
The Contributions of the candidate to venominormatics include, creation of protein sequence patterns and information highlighting the importance of the patterns as gleaned from the lteratures for family classification: profile HMM and MC-SVMs for conotoxin superfamily classification; in silico characterization of I1 and I2 conotoxin superfamilies; studies of interaction with Kv1 channels of typical members of I2 and 3 conotoxin superfamilies and development of improved methods for detecting membrane-spanning helices.
Chapter I starts with a brief account of venominformatics; bioinformatics for venoms and toxins.
Chapter 2 presents a regular expression based classification of Conus peptides.
Chapter 3 revisits the 28 entries previously grouped as I-conotoxin superfamily in UniProt Swiss-Prot knowledgebase (release 49.0) having four disulfide bonds with Cys arrangement C-C-CC-CC-C-C and they inhibit or modify ion channels of nerve cells.
Chapter 4 describes pseudo-amino acid composition and MC-SVMs approach for conotoxin superfamily classification.
Chapter 5 describes in silico detection of binding mode with Kv1.6 channel of J-superfamily conotoxin p114a from bermivorouos cone snail, Conus planorbis.
Chapter 6 presents a comparative sequence-structure-function analysis of naturally occurring Cys-rich peptides having the Knottin or inhibitor cystine knot(ICK) scaffold, from different plants and venomous animals based on information available in the knottin database(http://knottin.cbs.cnrs.fr/).
Chapter 7 describes the application of order-statistic filters and hydrophobicity profiles for detecting membrane-spanning helices.
Chapter 8 describes the role of context in the relationship between form and function for the true PDB hits of some non Cys-rich PROSITE patterns.
Chapter 9 summaries the important findings of the present studies on naturally occurring bioactive Cys-rich peptides with emphasis on Conus peptides and their interactions with respective target such as voltage-gated ion channels.
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Yang, Guang Yu Clement. "Rod-like Properties of Small Single Cones: Transmutated Photoreceptors of Garter Snakes (Thamnophis proximus)." Thesis, 2010. http://hdl.handle.net/1807/25524.
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While nocturnal basal snakes have rod-dominant retinae, diurnal garter snakes have all-cone retinae. Previous work from the Chang lab identified three visual pigments expressed in the photoreceptors of Thamnophis proximus: SWS1, LWS and RH1. I further characterized T. proximus photoreceptors using electron microscopy, immunohistochemistry, and in vitro protein expression. T. proximus have four types of morphological cones: double cones, large single cones, small single cones, and very small single cones. Some small single cones have rod-like features, such as rod-like outer-segment membranes and a lack of micro-droplets. Immunohistochemistry showed that rod-specific transducin is expressed in some T. proximus photoreceptors. In vitro expression of T. proximus RH1 produced a functional rhodopsin with λmax at 485nm, which corresponds to microspectrophotometry measurement from some small single cones. Current results suggest that small single cones of T. proximus may have evolved from ancestral rods, and secondarily acquired a cone-like morphology as adaptation to diurnality.
Books on the topic "Cone snails"
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Martin, C. V. The Rainbow Snakes in A dream come true. Madison, WI: Rainbow Snakes, 1997.
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John, Levy. We don't kill snakes where we come from: Two years in a Greek village. El Paso: Querencia Books, 1994.
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To amend title 18, United States Code, to include constrictor snakes of the species Python genera as an injurious animal: Report (to accompany H. R. 2811) (including cost estimate of the Congressional Budget Office). Washington, D.C: U.S. G.P.O., 2010.
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To amend Title 18, United States Code, to include constrictor snakes of the species Python genera as an injurious animal: Hearing before the Subcommittee on Crime, Terrorism, and Homeland Security of the Committee on the Judiciary, House of Representatives, One Hundred Eleventh Congress, first session, on H.R. 2811, November 6, 2009. Washington: U.S. G.P.O., 2010.
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Stuart, Jon, Abbie Rushton, and Di Hatchett. Project X CODE: Ladders and Snakes. Oxford University Press, 2021.
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Hua, Huilun. She (Shi er sheng xiao cong shu). Xin hua shu dian Shanghai fa xing suo fa xing, 1990.
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Cermak, Michael. Spectacular Snakes of Australia. CSIRO Publishing, 2008. http://dx.doi.org/10.1071/9780643101371.
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Spectacular Snakes of Australia showcases these beautiful creatures which play such an important part in our biodiversity. It portrays most of the species found in Australia, such as tiger snakes, copperheads, brown snakes, death adders and sea snakes, up close and personal. It also includes some unique photographs, such as the hatching of scrub pythons, that offer a rare glimpse into their more intimate lives.
The informative text, based on the latest research, describes the reproductive biology, behaviour, predators and prey of these reptiles, as well as their habitat and conservation values. Readers will explore the importance of colours and patterns in allowing snakes to blend into their environment, their defence and attack mechanisms, and the adaptations they have undergone to cope with their surroundings. In addition, the author provides some anecdotes on his encounters with snakes, and clears up a few myths regarding snake behaviour.
Richly illustrated with exceptional photographs, Spectacular Snakes of Australia features the deadly serious as well as the quirky – from snakes that love water to those with potent venom, and even snakes that are blind! This book is a real treat for snake lovers.
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Watharow, Simon. Living with Snakes and Other Reptiles. CSIRO Publishing, 2011. http://dx.doi.org/10.1071/9780643097223.
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Can you tell if a snake is venomous by its colour?
What is the real chance of being bitten by a snake?
Can you really die in 30 seconds?
Many of us have an instinctive fear of snakes and other reptiles. Over the last 200 years, we have built up a strong negative image of them, especially snakes. It is an image that has been reinforced by many fallacies and misconceptions.
Living with Snakes and Other Reptiles provides a layperson’s account of why these creatures behave the way they do and what makes people get into trouble. The book sheds new light on snakes, lizards and crocodiles, helps you to identify them and dispels some common myths and fallacies. In revealing the fascinating world of reptiles, the book provides the reader with the knowledge to better cope with them at home and in the workplace.
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Make It Tonight: Pizzas and Snacks (Cole"S Home Library Cookbooks). Cole Group, 1999.
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Teng she cheng wu (Zhongguo sheng xiao wen hua cong shu). Jing xiao Xin hua shu dian zong dian Beijing fa xing suo, 1998.
Find full textBook chapters on the topic "Cone snails"
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Palanisamy, Satheesh Kumar, Senthil Kumar Dhanabalan, and Umamaheswari Sundaresan. "Recent Developments and Chemical Diversity of Cone Snails with Special Reference to Indian Cone Snails." In Blue Biotechnology, 445–84. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2018. http://dx.doi.org/10.1002/9783527801718.ch14.
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Dutertre, Sébastien, John Griffin, and Richard J. Lewis. "Phyla Molluska: The Venom Apparatus of Cone Snails." In Marine and Freshwater Toxins, 327–40. Dordrecht: Springer Netherlands, 2016. http://dx.doi.org/10.1007/978-94-007-6419-4_8.
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Dutertre, Sébastien, John Griffin, and Richard J. Lewis. "Phyla Molluska: The Venom Apparatus of Cone Snails." In Marine and Freshwater Toxins, 1–10. Dordrecht: Springer Netherlands, 2015. http://dx.doi.org/10.1007/978-94-007-6650-1_8-1.
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Prashanth, Jutty Rajan, Sebastien Dutertre, and Richard James Lewis. "Revising the Role of Defense and Predation in Cone Snail Venom Evolution." In Evolution of Venomous Animals and Their Toxins, 105–23. Dordrecht: Springer Netherlands, 2017. http://dx.doi.org/10.1007/978-94-007-6458-3_18.
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Prashanth, Jutty Rajan, Sebastien Dutertre, and Richard James Lewis. "Revising the Role of Defense and Predation in Cone Snail Venom Evolution." In Evolution of Venomous Animals and Their Toxins, 1–18. Dordrecht: Springer Netherlands, 2016. http://dx.doi.org/10.1007/978-94-007-6727-0_18-1.
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Lewis, Richard J. "CHAPTER 9. Case Study 1: Development of the Analgesic Drugs Prialt® and Xen2174 from Cone Snail Venoms." In Drug Discovery, 245–54. Cambridge: Royal Society of Chemistry, 2015. http://dx.doi.org/10.1039/9781849737876-00245.
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Colella, Micol, Micaela Liberti, Francesca Apollonio, and Giorgio Bonmassar. "A Miniaturized Ultra-Focal Magnetic Stimulator and Its Preliminary Application to the Peripheral Nervous System." In Brain and Human Body Modeling 2020, 167–76. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-45623-8_9.
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AbstractTranscranial magnetic stimulation (TMS) is a noninvasive brain stimulation technique used in the clinic to treat several neurological disorders and psychiatric diseases. One of TMS’s significant limitations is its low spatial resolution, which often results in a mismatch between the target area in the brain and the stimulation site on the scalp. To enhance its spatial resolution, we designed and built a complete stimulation system complete with a millimetric-diameter coil and microscopic traces (μCoil). The first tests conducted on healthy volunteers showed that the μCoil stimulation of the radial nerve in the wrist could indeed evoke somatosensory nerve action potentials (SNAPs). In this chapter, we study this nerve stimulation system with electromagnetic and neuron simulators on a neurofunctionalized model from the Virtual Population (ViP v.4) and a μCoil figure-8 geometry. In particular, we study how changes in the μCoil geometry, such as the number of layers, shape, and length of an iron or air core, may help to promote the generation of somatosensory nerve action potentials.
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Gopakumar, K., and Balagopal Gopakumar. "Cone Snails." In Health Foods from Ocean Animals, 133–37. CRC Press, 2020. http://dx.doi.org/10.1201/9781003084242-11.
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Green, B. R., and B. M. Olivera. "Venom Peptides From Cone Snails." In Na Channels from Phyla to Function, 65–86. Elsevier, 2016. http://dx.doi.org/10.1016/bs.ctm.2016.07.001.
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"Cone Snail Venom Peptides and Future Biomedical Applications of Natural Products." In Chemical Biology of Natural Products, edited by David J. Newman, Gordon M. Cragg, and Paul G. Grothaus, 425–89. Boca Raton : CRC Press, [2017]: CRC Press, 2017. http://dx.doi.org/10.1201/9781315117089-12.
Full textConference papers on the topic "Cone snails"
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Hendricks, Jonathan R. "ULTRAVIOLET (UV) LIGHT REVEALS THE SHELL COLORATION PATTERNS AND PHYLOGENETIC DIVERSITY OF MIOCENE CONE SNAILS (CONIDAE) FROM THE GATUN FORMATION OF PANAMA." In GSA Annual Meeting in Denver, Colorado, USA - 2016. Geological Society of America, 2016. http://dx.doi.org/10.1130/abs/2016am-281649.
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Renardy, Yuriko Y. "Snake and Corkscrew Waves in Core-Annular Flow." In ASME 1997 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1997. http://dx.doi.org/10.1115/imece1997-0757.
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Abstract Core-annular flow of two fluids in down-flow is examined at the onset of a n = ±1 non-axisymmetric instability. This leads to a pattern selection problem; the bifurcating solutions are traveling waves and standing waves. The former travel in the azimuthal direction as well as the axial direction and would be observed as corkscrew waves. The standing waves travel in the axial direction but not in the azimuthal direction and appear as snakes. Weakly nonlinear interactions are studied to see whether one of these waves will be stable to small amplitude perturbations. The corkscrews are found to be preferred when the armulus is narrow and snakes are preferred when the annulus is wide.
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Bullard, Elizabeth M., Yurena Yanes, and Arnold I. Miller. "SPATIO-TEMPORAL VARIATIONS IN LAND-SNAIL ASSEMBLAGES RECOVERED FROM A PLEISTOCENE CINDER CONE." In 50th Annual GSA North-Central Section Meeting. Geological Society of America, 2016. http://dx.doi.org/10.1130/abs/2016nc-275157.
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Bernhauer, David. "Code Visualization for Plagiarism Detection." In 2022 Ninth International Conference on Social Networks Analysis, Management and Security (SNAMS). IEEE, 2022. http://dx.doi.org/10.1109/snams58071.2022.10062664.
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Meyle, Lucy, Emily O'Hara, and Monique Redmond. "The Colophon: Where moving parts come together." In LINK 2021. Tuwhera Open Access, 2021. http://dx.doi.org/10.24135/link2021.v2i1.131.
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This proposal considers the colophon as a conceptual structure for thinking through lists and listing within our creative practice(s). Conventionally, the colophon is a short piece of text that details information about the making of a publication or its intended use. Most often, the colophon specifies the how, where, and when: the typeface and paper stock; the location, date, edition number, and method of printing. It can also foreground the relational aspects of publishing – the with who or the why here. Colophons appear at the opening or the closing of a publication, and the information within them can form a kind of ballast to what precedes or succeeds them. That is, the listing of the material, processual, and relational labour that went into the making of publications is called forward in the colophon and acknowledged as structural necessity. Often, we are led to ask, how is this conception of the colophon useful in thinking about the other types of lists and listings that make their way into our collective practices? —Runsheets, Material lists, Contents, Title lists, Indexes, Captions, Legends, Rosters, Glossaries, Registers, Manifests, Chronologies— These modes of listing communicate relevant and important contexts and, in that way, become a conceptual part of creative works themselves. As formats, they are all also citational practices where the materials, processes, information, and relations are shared freely – as any written text would be in a publication’s reference list. In their book, The Hundreds (2019), cultural theorists Lauren Berlant and Kathleen Stewart list Adorno and Agamben texts next to “An egg-cooking machine” and “A few pansies stuck in a window box” in the reference section, all alphabetised under the title “Some Things We Thought With”1. This type of list (and the concept of a colophon itself) is not an indiscriminate breaking-down into separate parts but a strategic highlighting of the conditions and abstractions of the artwork. The colophon as a structure in this context exists not only to acknowledge what contributes to a publication but also to trace possible points of departure from convention. As a tactic within creative practice, the colophon is like a conceptual abstraction; it holds all of the constituent parts that make up a project in one place. The ‘—with’ that Berlant and Stewart explore is key to the how, where, and when of relations that the doing of listing brings together. As artists working in the inter-related fields of socially engaged art, object-making, installation, and publication, our list of interests include the moon, the water, the sky; flowers, ceramics, printed matter; ducks, snails, butter. This paper will share our three perspectives on listing as a synchronous tactic with the functioning action of a colophon. Where words and images get to turn, twist, veer, bow, dip, and nod, and the conceptual form of a project takes shape with things.
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Al-Obeidat, Feras, Oluwasegun Adedugbe, Anoud Bani Hani, Elhadj Benkhelifa, and Munir Majdalawieh. "Cone-KG: A Semantic Knowledge Graph with News Content and Social Context for Studying Covid-19 News Articles on Social Media." In 2020 Seventh International Conference on Social Networks Analysis, Management and Security (SNAMS). IEEE, 2020. http://dx.doi.org/10.1109/snams52053.2020.9336541.
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Abe, Mitsuhiko, Hironori Koga, Takafumi Yoshida, Shinichiro Hanada, Takumi Kawaguchi, Masahiro Sakata, Eitaro Taniguchi, et al. "Abstract 2309: Hepatitis C virus core protein in combination with interleukin-6 induces epithelial-mesenchymal transition through upregulation of Snail and E2A in human hepatocyte-derived cells." In Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC. American Association for Cancer Research, 2010. http://dx.doi.org/10.1158/1538-7445.am10-2309.
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Garzón, Gabriela, and John Sebastián Nieto López. "PROPUESTA DE LINEAMIENTOS DE ECONOMÍA CIRCULAR EN LAS ETAPAS DE GENERACIÓN Y ALMACENAMIENTO EN LA GIRS DOMICILIARIOS, BIODEGRADABLES Y PLÁSTICO, DEL BARRIO TABORA, BOGOTÁ D.C." In Mujeres en ingeniería: empoderamiento, liderazgo y compromiso. Asociacion Colombiana de Facultades de Ingeniería - ACOFI, 2021. http://dx.doi.org/10.26507/ponencia.1869.
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La investigación desarrollada por ingenieros ambientales se enfoca en la propuesta de lineamientos de economía circular en las etapas de generación y almacenamiento en la Gestión Integral de Residuos Sólidos (GIRS) domiciliarios, biodegradables y plásticos, para el barrio Tabora, Bogotá D.C., Colombia. Esta propuesta surge inicialmente por la preocupación mundial en relación con la alta generación de residuos sólidos urbanos y sus efectos adversos, ya que no son separados ni aprovechados correctamente y son depositados en rellenos sanitarios. Esta problemática es identificada en el barrio Tabora, donde se generan residuos sólidos domiciliarios que no son separados en la fuente haciendo que se mezclen y pierdan su valor, su oportunidad de aprovecharlos para otro fin; entonces, todos estos residuos son considerados como basura. Tales bolsas son depositadas en las aceras y en los contenedores destinados al almacenamiento temporal donde se acumulan desbordándose del contenedor y/o dispersándose por las aceras liberando lixiviados, malos olores, y proliferando vectores como moscas y palomas. Incluso, es tan solo una muestra de la problemática en Bogotá a nivel social, ecológico y económico, ya que esa mezcla de residuos aprovechables y no aprovechables se disponen como basura en el Relleno Sanitario Doña Juana y se acumulan toneladas provenientes de todos los barrios de la ciudad. Por eso, es la mayor razón para proponer alternativas de solución desarrolladas desde la ingeniería. Por lo tanto, el proyecto de aplicación comienza con el diagnóstico de la gestión actual de los residuos, consistiendo en la recolección de información primaria y secundaria realizando recorridos y caracterización por cuarteo. Prosigue el análisis y contraste de información con casosde éxito de aprovechamiento de residuos biodegradables y de plástico para seleccionar la mejor alternativa aplicable al barrio Tabora. Así pues, se establecen los lineamientos de economía circular que puedan adaptarse al caso de estudio para crear valor, teniendo en cuenta los grupos de interés más representativos dentro de este sistema. Es así como se identifica que los tipos de residuos plásticos más generados en el barrio Tabora son el PP (polipropileno) y el PEAD (polietileno de alta densidad), bases de productos como paquetes de snacks y bolsas de supermercado; y se propone que se integren a la economía circular con los lineamientos: rechazar, reducir, reutilizar, repensar y reciclar, por medio de su aprovechamiento en materiales de construcción ecológicos y de artesanías Así mismo, se identifica que los tipos de residuos biodegradables generados en mayor cantidad son los restos de verduras y frutas, y se propone que se integren a la economía circular con los lineamientos: rechazar, reutilizar, y repensar, por medio de su aprovechamiento en compostaje y como materia prima para la alimentación de animales.
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Dimitriu, Anda. "TEACHING ENGLISH IN A DIGITAL WORLD: THE ADVANTAGES AND DISADVANTAGES OF INTRODUCING VIDEOS IN ENGLISH LANGUAGE COURSES." In eLSE 2017. Carol I National Defence University Publishing House, 2017. http://dx.doi.org/10.12753/2066-026x-17-214.
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As the international language of our times, English has benefitted in recent years from a myriad of pedagogical approaches, case-based studies or philosophical musings. This phenomenon has also been doubled by the proliferation of technology in the twenty-first century and the shift in mentality on the part of the newer generations, who now view short video sequences as a commonplace aspect of their lives. As a natural consequence, specialists in the field of pedagogy and didactics have also drawn attention to the opportunities this new technology might bring in the classroom, and have even tried and succeeded to incorporate readily available videos in the teaching-learning process they were a part of. Still, implementing a change in curriculum will inherently bring out obstacles as well; so, disappointed that the change was not revolutionary in nature or all-encompassing in effect, many have given up and returned to the well-trodden paths of dividing English learning in the aspects they were familiar with, leaving videos or films aside in favour of written texts or grammatical exercises. But modest as they may be, and despite the drawbacks which come with this change, I believe the advantages of video clips in the teaching of English are important from a twofold point of view: firstly, videos may prove a very useful tool of placing specialised vocabulary or grammatical structures in a clearer context for the generations who live surrounded by images and video snaps, and secondly, they could provide the students with a chance to be immersed in the culture and frame of mind of native speakers, if only for a short while. Therefore, this present paper will offer an image of the advantages and disadvantages of introducing videos and movie clips in the curriculum of English learners, and will do so by analysing the theoretical foundation of such a change, as well as by giving concrete examples of how a simple video could improve the learning experience for students with various interests and specialisations.
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Bellabiod, Sofiane, Ozgur Karacali, Abdelkader Aris, Abdelhakim Deghmoum, and Bertrand Theuveny. "Evaluating Phase Blockages and Mobility Changes During Pressure Transient Analysis." In SPE Middle East Oil & Gas Show and Conference. SPE, 2021. http://dx.doi.org/10.2118/204535-ms.
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Abstract Pressure transient analysis (PTA) is a cogent methodology to evaluate dynamics of hydrocarbon reservoirs. Numerous analytical and numerical models have been developed to model various types of wellbore, reservoir, and boundary responses. However, the near-wellbore region remains to be perplexing in pressure transient analysis. In this paper we investigate the pressure transient behavior of phase blocking and mobility variations caused by fluid phase interactions or properties, such as viscous drag forces and surface tension at the near-wellbore region and their impact on pressure transient evaluation. We have used real field examples to scrutinize relative effects of mobility variations in pressure transients. The impact of capillary number (Nc) acting on the near-wellbore region and its influence on pressure transient behavior and skin alteration were examined in detail. Several real field examples honoring actual reservoir rock special core analysis (SCAL) and fluid pressure/volume/temperature (PVT) properties have been studied. Actual field data discussed in this paper for PTA were captured during drill stem testing (DST) operations from various hydrocarbon reservoirs in the Berkine Basin of Algeria. PVT laboratory-measurement-based fluid properties were used in conjunction with tuned equation of state (EOS) models to ensure consistency between wells and reservoirs. Pressure transient analysis of a gas condensate reservoir system can depict various mobility regions, especially while flowing below dew point pressure. In some cases, three-distinct-mobility regions can be identified as: a far-field zone with initial gas and condensate saturation; a mid-field zone with increased condensate saturation and lower gas relative permeability; and a near-wellbore zone with high Nc which increases gas relative permeability and mobility. These three-distinct-mobility regions form due to condensate dropping out and fluid interactions in the near wellbore. We demonstrate, with real-life field examples of the near-wellbore region, how the relative effects of viscous drag forces and surface tension forces acting across the liquid and gas interface can enable the reference fluid phase to regain its mobility. We further investigate the evaluation of skin factor in such circumstances and show how the existence of phase blocking and velocity stripping can cause over-estimation or under-estimation of skin factor. We present a novel set of real field examples and relations between various zones in hydrocarbon reservoirs to avoid snags of misleading pressure transient interpretations and how composite models can be accurately used to represent complex cases. Field examples from Algerian hydrocarbon reservoirs are depicted. The findings could be easily applied for similar reservoirs in other parts of the globe to identify and model such intricate systems.
Reports on the topic "Cone snails"
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Martínez Jorge, Angel, Javier Martínez Santos, and Jorge Galindo. Los efectos del aumento del IVA en el consumo de las bebidas azucaradas en España. Esade EcPol, March 2023. http://dx.doi.org/10.56269/20230328/amj.
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En 2021 el Gobierno subió el IVA a las bebidas azucaradas y edulcoradas del 10 al 21%. La medida redujo de manera significativa el consumo medio del tercio de hogares con menor nivel económico. Lo hizo en unos 11 litros por hogar al año. Pero no tuvo un efecto apreciable en el consumo de los hogares de nivel económico medio y alto. El impacto del impuesto fue aún mayor en los hogares de menor nivel económico con hijos, donde la caída del consumo llegó a 25 litros por hogar al año. Al mismo tiempo, dentro del tercio de hogares de menor nivel económico la subida del IVA provocó un descenso de unos 5€/año por hogar (es decir, un 10,5% menos) en el gasto de snacks, bienes que se suelen consumir con estas bebidas.