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1

Comparação dos acidentes causados por Bothropoides jararaca (Serpentes: Viperidae) com e sem envenenamento atendidos no Hospital Vital Brazil do Instituto Butantan.  

E-print Network

??No Brasil, 90% dos acidentes por serpentes peçonhentas são causadas por Bothropsafin (Bothrops, Bothropoides, Bothriopsis, Bothrocophias e Rhinocerophis), com predominância nos meses quentes e chuvosos,… (more)

Alessandra Furtado Nicoleti

2010-01-01

2

Historical Biogeography of the Western Rattlesnake (Serpentes: Viperidae: Crotalus viridis), Inferred from  

E-print Network

Historical Biogeography of the Western Rattlesnake (Serpentes: Viperidae: Crotalus viridis- snake (Crotalus viridis) using phylogenetic analysis of mitochondrial DNA sequences from 1345 bp populations from east and south of the Rocky Moun- tains (conventionally referred to as Crotalus viridis

Thorpe, Roger Stephen

3

Características biológicas e inmunológicas del veneno de Bothrops cotiara (Serpentes: Viperidae)  

Microsoft Academic Search

Biological and immunological characteristics of the poison of Bothrops cotiara (Serpentes: Viperidae). Bothrops cotiara is a venomous snake sporadically found in the province of Misiones in Argentina, South of Brazil and Paraguay. Data on the clinics of the envenomation produced by its bite and on its venom are scarce. There is no information on the neutralizing capacity of the antivenoms

Adolfo Rafael de Roodt; Judith Estévez; Jorge Adrián Dolab; Marcelo Víctor Manzanelli; Nicolás Piñeiro; Jorge Francisco Paniagua; Alejandro Urs Vogt

2006-01-01

4

Heterochromosomen bei Vipera berus L. (Viperidae, Serpentes)  

Microsoft Academic Search

Summary A dimorphic pair of chromosomes was found among the macrochromosomes in mitosis of females ofVipera berus L. It corresponds to a pair of medium-sized chromosomes in the male. The conclusion is drawn that females are heterogametic (ZW-type), males being homogametic (ZZ-type). Similar observations were made inVipera aspis L.,Natrix natrix L., andNatrix maura L.

H. R. Kobel

1962-01-01

5

[The structure and ultrastructure of the pulp in Vipera aspis (Viperidae)].  

PubMed

The present paper using classical and transmission electron microscopy brings the first data on the pulp of the fangs of Viperidae (poisonous serpents with terrestrial or semi-aquatic habits). The pulp of the fangs of Viperidae shows a poor collagen and fibroblast content and a high developed vascular system. The odontoblasts are polarized, with a high organelle content. The interconnections are constituted of lateral "gap junction" systems. At a late secretion stage, the odontoblastic processes show a poor cytoplasm, mainly constituted of microfilaments. PMID:2695189

Kattie, A L; Le Cabellec, M T; Cottrel, M; Kerebel, L M

1989-12-01

6

Prospection, structural analysis and phylogenetic relationships of endogenous gamma-phospholipase A(2) inhibitors in Brazilian Bothrops snakes (Viperidae, Crotalinae).  

PubMed

During the last 20 years, there have been an increasing number of reports on endogenous phospholipase A(2) inhibitors (PLIs) in the sera of snakes. These studies have demonstrated the existence of three different structural classes of PLIs (alpha, beta and gamma). The gamma class members are potent inhibitors of phospholipases A(2) (PLA(2)) from the venom of Viperidae snakes. These enzymes, together with the mammalian pro-inflammatory PLA(2), belong to the IIA class of the PLA(2)-superfamily. Although coming from distinct sources, these phospholipases A(2) share main structural features. For this reason, gammaPLIs have been considered as potential models for the development of selective inhibitors of pro-inflammatory PLA(2) in humans. In spite of the rich diversity of the ophidian fauna in Brazil, only two gammaPLI representatives, from Crotalus durissus terrificus and Lachesis muta, have been described in Brazilian snakes so far. Here we investigated the presence of transcripts of novel gammaPLIs in six Bothrops species (Viperidae, Crotalinae) commonly found in our country: Bothrops alternatus, Bothrops erythromelas, Bothrops jararaca, Bothrops jararacussu, Bothrops moojeni and Bothrops neuwiedi. gammaPLI transcripts were present in every species analysed. The deduced mature proteins possessed 181 amino acid residues following a 19-residue signal peptide, similar to the gammaPLIs from C. d. terrificus taken as our model, with the exception of the deduced proteins from B. erythromelas and B. neuwiedi snakes. In these particular cases, an insertion of 4-amino acid residues was consistently present. A Bayesian tree was obtained for the Brazilian Bothrops gammaPLIs, showing four clusters: (1) L. muta and B. jararacussu, (2) B. alternatus, (3) B. erythromelas and B. neuwiedi, (4) B. jararaca and B. moojeni. Detailed structural analysis and further comparisons of these novel Bothrops inhibitors with gammaPLIs from New and Old World snakes are provided. PMID:18620721

Estevão-Costa, Maria Inácia; Rocha, Bruno Coelho; de Alvarenga Mudado, Maurício; Redondo, Rodrigo; Franco, Glória Regina; Fortes-Dias, Consuelo Latorre

2008-07-01

7

New methodology for the obtainment of antibothropic factors from the South American opossum (Didelphis marsupialis) and jararaca snake (Bothrops jararaca).  

PubMed

The antibothropic factor (ABF) from D. marsupialis was collected from perforated hollow plastic golf balls which were surgically implanted subcutaneously in anesthetized opossums, a technique originally described for the production of polyclonal antibodies. Two months after the implantation of the balls, approximately 15 ml of seromatous fluid from D. marsupialis (SFDm-50 mg total protein/ml) could be recovered monthly. Opossum serum as well as SFDm showed similar SDS-PAGE profiles and antihemorrhagic potencies against Bothrops jararaca snake venom (Bjv). The presence of ABF in SFDm was confirmed by immunoblotting, using rabbit polyclonal antibodies raised against ABF isolated from opossum serum. ABF isolated from SFDm or from serum by ion-exchange chromatography showed identical chromatographic and electrophoretic profiles. ABF fromboth sources displayed very similar antihemorrhagic and anticaseinolytic activities against Bjv. In the case of B. jararaca, polyethylene perforated tubes were inserted in the abdominal cavity and two months after implantation, approximately 4 ml of seromatous fluid from B. jararaca (SFBj-23 mg total protein/ml) were recovered. B.jararaca serum and SFBj showed the same native and SDS-PAGE band pattern. Both serum and SFBj inhibited Bjv hemorrhagic activity. We conclude that this new methodology is very suitable for continuously obtaining opossum ABF and SFBj, in large scale and in an easier way, avoiding animal suffering and eventual sacrifice. PMID:10414866

Neves-Ferreira, A G; Valente, R H; Sá, P G; Rocha, S L; Moussatché, H; Domont, G B; Perales, J

1999-10-01

8

Historical biogeography of the Western Rattlesnake (Serpentes: viperidae: Crotalus viridis), inferred from mitochondrial DNA sequence information.  

PubMed

We infer the phylogeography of the Western Rattlesnake (Crotalus viridis) using phylogenetic analysis of mitochondrial DNA sequences from 1345 bp of the genes for cytochrome b and NADH dehydrogenase subunit 4. Two main clades are revealed: one includes populations from east and south of the Rocky Mountains (conventionally referred to as Crotalus viridis viridis and C. v. nuntius), and the other consists of populations west of the Rocky Mountains. Within the western clade, a population from southern Arizona (C. v. cerberus) represents the sister taxon to the remaining western populations. The conventional subspecies recognized in this species do not fully correspond to the phylogenetic pattern, and a review of the systematic status of several populations is needed. Our data allow the inferences that small body size evolved twice and that the ability of one population (C. v. concolor) to secrete highly lethal toxins related to Mojave toxin arose within the complex. Our phylogeny should represent the basis for further studies on the causes of geographical variation in this complex. PMID:10837156

Pook, C E; Wüster, W; Thorpe, R S

2000-05-01

9

Historical Biogeography of the Western Rattlesnake (Serpentes: Viperidae: Crotalus viridis), Inferred from Mitochondrial DNA Sequence Information  

Microsoft Academic Search

We infer the phylogeography of the Western Rattlesnake (Crotalus viridis) using phylogenetic analysis of mitochondrial DNA sequences from 1345 bp of the genes for cytochrome b and NADH dehydrogenase subunit 4. Two main clades are revealed: one includes populations from east and south of the Rocky Mountains (conventionally referred to as Crotalus viridis viridis and C. v. nuntius), and the

Catharine E. Pook; Wolfgang Wüster; Roger S. Thorpe

2000-01-01

10

[Neutralization of the hemorrhagic effect induced by Bothrops asper (Serpentes: Viperidae) venom with tropical plant extracts].  

PubMed

Organic extracts representing 48 species included in 30 families of Costa Rican tropical plants were evaluated for their ability to neutralize hemorrhagic activity induced by the venom of the snake Bothrops asper. A bioassay in mice was used, based on intradermal injection of either venom or venom-extract mixtures followed by the measurement of hemorrhagic areas. Total inhibition of hemorrhage was observed with the ethanolic, ethyl acetate and aqueous extracts of Bursera simaruba, Clusia torresii, C. palmana, Croton draco, Persea americana, Phoebe brenesii, Pimenta dioica, Sapindus saponaria, Smilax cuculmeca and Virola koschnyi. Chemical analysis of these extracts identified catequines, flavones, anthocyanines and condensated tannins, which may be responsible for the inhibitory effect observed, probably owing to the chelation of the zinc required for the catalytic activity of venom's hemorrhagic metalloproteinases. PMID:10883329

Castro, O; Gutiérrez, J M; Barrios, M; Castro, I; Romero, M; Umaña, E

1999-09-01

11

Is the population of Crotalus durissus (Serpentes, Viperidae) expanding in Brazil?  

PubMed Central

Crotalus durissus are found from Mexico to northern Argentina in a highly disjunct distribution. According to some studies, this species is prone to occupy areas disturbed by human activities and floods comprise a plausible method of dispersal as inferred for some North American rattlesnakes. Based on the literature, it seems plausible that Crotalus durissus expanded their natural distribution in Brazil due to floods, but only in a few municipalities in Rio de Janeiro State. Data entries of Butantan Institute, in São Paulo, Brazil, from 1998 to 2012 show a declining tendency of snakes brought by donors. In addition, research shows no evidence of Crotalus durissus being an expanding species in the Brazilian territory. PMID:24314146

2013-01-01

12

Descriptions of six new species of Caryospora (Apicomplexa: Eimeriidae) from Guatemalan snakes (Serpentes: Colubridae and Viperidae).  

PubMed

One hundred and seventy snakes were collected in Guatemala and examined for coccidia. Of these, 8 individuals representing 6 host species were positive for Caryospora spp., 6 of which are described as new species. Sporulated oocysts of Caryospora bothriechis n. sp. from Bothriechis aurifer are spheroidal to subspheroidal, 12.7 x 12.5 (12-14 x 12-13) microm, with a length/width (L/W) ratio of 1.0; they lack a micropyle (M) or oocyst residuum (OR), but 1 large polar granule (PG) is usually present. Sporocysts are ovoidal, 9.0-7.5 (8-10 x 7-8) microm, and have a L/W ratio of 1.2, and a Stieda body (SB) and sporocyst residuum (SR). Oocysts of Caryospora coniophanis n. sp. from Coniophanes imperialis are spheroidal to subspheroidal, 18.8 x 18.1 (17-20.5 x 16-20) microm, with a L/W ratio of 1.0; they lack a M and OR, but 1 large PG is usually present. Sporocysts are ovoidal, 13.2 x 9.4 (12-15 x 8-10) microm with a L/W ratio of 1.4, and a SB, substieda body (SSB), and SR. Oocysts of Caryospora conophae n. sp. from Conophis lineatus are spheroid to subspheroidal, 20.4 x 19.5 (17-26 x 17-25) microm, with a L/W ratio of 1.0; they lack a M and OR, but 1 large PG is usually present. Sporocysts are ovoidal, 13.1 x 9.8 (11-15 x 8-11) microm with a L/W ratio of 1.3 and a SB, SSB, and SR. Oocysts of Caryospora guatemalensis n. sp. from Lampropeltis triangulum are spheroidal to subspheroidal, 23.9 x 23.2 (20-27 x 20-26) microm, with a L/W ratio of 1.0; they lack a M and OR, but 1 large PG is usually present. Sporocysts are ovoidal, 14.4 x 10.6 (13-18 x 9-13) microm, with a L/W ratio of 1.4 and a SB, SSB, and SR. Oocysts of Caryospora mayorum n. sp. from Conophis lineatus are spheroidal to subspheroidal, 25.6 x 24.4 (24-27 x 24-25) microm, with a L/W ratio of 1.0; they lack a M and OR, but 1 large PG is usually present. Sporocysts are ovoidal, 16.3 x 11.9 (16-18 x 11-13) microm, with a L/W ratio of 1.4 and a SB, SSB, and SR. Oocysts of Caryospora zacapensis n. sp. from Masticophis mentovarius are spheroidal to subspheroidal, 22.5 x 21.8 (19-25 x 18-25) microm, with a L/W ratio of 1.0; they lack a M and OR, but 1 large PG is usually present. Sporocysts are ovoidal, 14.6 x 11.4 (11-16 x 10-13) microm, with a L/W ratio of 1.3 and a SB, SSB, and SR. PMID:16539030

Seville, Robert S; Asmundsson, Ingrid M; Campbell, Jonathan A

2005-12-01

13

The Evolutionary Implications of Hemipenial Morphology of Rattlesnake Crotalus durissus terrificus (Laurent, 1768) (Serpentes: Viperidae: Crotalinae)  

PubMed Central

Most amniotes vertebrates have an intromittent organ to deliver semen. The reptile Sphenodon and most birds lost the ancestral penis and developed a cloaca-cloaca mating. Known as hemipenises, the copulatory organ of Squamata shows unique features between the amniotes intromittent organ. They are the only paired intromittent organs across amniotes and are fully inverted and encapsulated in the tail when not in use. The histology and ultrastructure of the hemipenes of Crotalus durissus rattlesnake is described as the evolutionary implications of the main features discussed. The organization of hemipenis of Crotalus durissus terrificus in two concentric corpora cavernosa is similar to other Squamata but differ markedly from the organization of the penis found in crocodilians, testudinata, birds and mammals. Based on the available data, the penis of the ancestral amniotes was made of connective tissue and the incorporation of smooth muscle in the framework of the sinusoids occurred independently in mammals and Crotalus durissus. The propulsor action of the muscle retractor penis basalis was confirmed and therefore the named should be changed to musculus hemipenis propulsor.The retractor penis magnus found in Squamata has no homology to the retractor penis of mammals, although both are responsible for the retraction of the copulatory organ. PMID:23840551

Porto, Marcovan; de Oliveira, Marco Antonio; Pissinatti, Lorenzo; Rodrigues, Renata Lopes; Rojas-Moscoso, Julio Alejandro; Cogo, José Carlos; Metze, Konradin; Antunes, Edson; Nahoum, César; Mónica, Fabíola Z.; De Nucci, Gilberto

2013-01-01

14

Discovery of a Novel Accessory Structure of the Pitviper Infrared Receptor Organ (Serpentes: Viperidae)  

PubMed Central

The facial pits of rattlesnakes, copperheads, lanceheads, bushmasters and other American and Asian pitvipers (Crotalinae) are highly innervated and densely vascularized infrared (IR) receptor organs. For over a century, studies have focused on a small sample of model species from North America and Asia. Based on an expanded survey of Central and South American crotalines, we report a conspicuous accessory structure composed of well-defined papillae that project from the anterior orbital adnexa. The papillae are continuous with the inner chamber of the IR receptor organ and our histological and ultrastructural data suggest that they possess a well-developed nervous network and extensive vascularization; however, they lack the characteristic IR-sensitive terminal nerve masses found in the IR-receptive pit membrane. The function of the IR receptor organ papillae is unknown. PMID:24595025

Bolívar-G, Wilmar; Antoniazzi, Marta M.; Grant, Taran; Jared, Carlos

2014-01-01

15

Natural history of the terciopelo Bothrops asper (Serpentes: Viperidae) in Costa Rica.  

PubMed

The terciopelo Bothrops asper is the only lancehead species widely distributed in the humid lowlands of Middle America and northwestern South America. Its large body size, relative abundance and cryptic habits contribute to the high incidence of snakebites induced by this species throughout its distribution. The terciopelo plays an important role in ecosystems, both as prey and as a generalist predator. Diet comprises a great variety of prey items, including some species that are considered nuisances. B. asper, as other lancehead species, exhibits a notable ontogenetic shift in diet, consuming ectotherms (mainly frogs and lizards) when young, and increasingly incorporating birds, rodents, and other small mammals with maturity. Adult terciopelos also consume large anurans, especially when endothermic prey availability is low. Using radiotelemetry we determined home range and movement patterns from 28 individual B. asper at La Selva Biological Station, Costa Rica. Overall home range estimates are relatively small compared with other pitvipers, averaging between 3.71ha and 5.95ha; home range size did not differ between males and females. Movement patterns are largely aseasonal and consist of short (<10 m) movements between daytime shelter and nocturnal ambush sites within a given area, interspersed with longer distance (>50 m) movements to new foraging areas. Habitat use is related to prey availability and therefore to foraging strategy. Our data support a strong preference for areas near swamps by both sexes. Reproduction in B. asper is highly seasonal, and--apparently--biannual. Reproductive cycles in Costa Rica are tightly related to rainfall patterns. Therefore, the timing of breeding differs between populations in the Caribbean and Pacific lowlands. Bothrops asper is adapted to areas with low levels of disturbance along the agricultural frontier, and consequently it is not rare to find it in or near human dwellings. However, despite popular belief, no evidence supports a purported increase in population density of this species in Costa Rica. Despite human persecution and substantial modification of habitat, B. asper is a species with a conservation status of least concern, and probably will likely persist well into the future. Thus, it is important to learn how to coexist with this species, and to improve mechanisms for the prevention and treatment of accidental snakebite and its consequences. PMID:19563822

Sasa, Mahmood; Wasko, Dennis K; Lamar, William W

2009-12-01

16

Agathos Daimon and the Asklepian serpent.  

PubMed

Much conjecture abounds about the origin of the Asklepian serpent of healing, this latter the universal metonym for curative medicine. Iconographic evidence of Asklepios with his staff-entwined serpent exists from Hippocratic times. Many theories exist about the origin of this reptilian symbol of curative medicine. Speculation has ranged from the skin-shed serpent emergent in new and robust health to putative associations with earlier Egyptian and Babylonian anguine (snake) symbols of life-determining power. Other scholars have drawn attention to the Palaeolithic, Neolithic and later Bronze-Age associations with serpent veneration in the context of rain and fertility religious invocations in India; and in many other cultures. In the South Pacific, in Australia and in Central and South America, serpents were regarded as spirits of the earth, often chthonian spirits who possessed life-giving powers. In Chaldean and Arabic etymology, the words for "serpent" and "life" have a synergy. In Classical Greece, the Agathos Daimon was literally the "noble spirit", a personal companion spirit ensuing health and good fortune. The Agathos Daimon was portrayed in iconography as a serpent, or as a fit and comely youth. This paper conjectures that the serpentine Agathos Daimon was one origin of the Asklepian symbol of medicine, portrayed as the serpent associated of the Homeric Asklepios. In later Roman times, the Agathos Daimon was transliterated to the agathodaemon, a protective companion spirit both of individuals and of the homes in which they lived. This benign resident spirit featured prominently in Roman art and was a common feature as a protective household spirit in first century homes at both Pompeii and Herculaneum. The agathodaemon motif also featured on Roman coins, such as bronze diobols of Antoninus Plus (138 - 161 A.D.) from Alexandrian mints in Egypt. In the twenty-first century, the serpentine Agathos Daimon is honoured not only as the symbol of medicine; but is daily acknowledged in toasts to "Good Health". PMID:22043596

Pearn, John

2011-06-01

17

Hypericum brasiliense plant extract neutralizes some biological effects of Bothrops jararaca snake venom  

PubMed Central

Alternative treatments for snake bite are currently being extensively studied, and plant metabolites are considered good candidates for such purpose. Here, the ability of a crude ethanolic extract of Hypericum brasiliense plant in neutralizing Bothrops jararaca snake venom was investigated by in vitro (coagulation, hemolysis or proteolysis) and in vivo (hemorrhage, lethality and edema) biological assays. We describe for the first time the ability of H. brasiliense extracts to inhibit some pharmacological effects of a Brazilian snake venom. Inhibitory assays were performed by incubating B. jararaca venom with H. brasiliense extracts for 30min at room temperature before the assays were performed. The results showed that H. brasiliense extracts impaired lethality, edema, hemorrhage, hemolysis, proteolysis as well as fibrinogen or plasma clotting induced by B. jararaca venom. This indicates that H. brasiliense extracts can provide promising agents to treat B. jararaca envenomation. PMID:21654896

Assafim, Mariane; de Coriolano, Eduardo Coriolano; Benedito, Sérgio Eufrázio; Fernandes, Caio Pinho; Lobo, Jonathas Felipe Revoredo; Sanchez, Eladio Florez; Rocha, Leandro Machado; Fuly, André Lopes

2011-01-01

18

Vipera berus and V. ammodytes (Serpentes:Viperidae) represent new host for Caryospora simplex (Apicomplexa:Eimeriidae) in Europe.  

PubMed

During a survey of the coccidian parasites of reptiles, caryosporan oocysts wee found in the faeces of wild and captive European viperid snakes Vipera berus (L.) and V. ammodytes (L.). Thirty two of 37 examined V. berus (86%) and 9 of 17 examined V. ammodytes (53%) specimens were found to be passing caryosporan oocysts. Morphological characters of all caryosporan isolates were identical and fitted well with the description of Caryospora simplex Léger, 1904. Experimental inoculation of severe combined immunodeficient (SCID) mice with seven isolates of C. simplex from V. berus or V. ammodytes confirmed the heteroxenous life cycle pattern, for the first time for isolates of evidently European origin. Caryosporan developmental stages were observed in the connective tissues of the nose, cheeks, ear and scrotum in all inoculated SCID mice. V. berus and V. ammodytes represent new hosts for C. simplex. The present paper represents the first widely based report on coccidian parasites of the genus Caryospora Léger in European viperids. Our findings indicate a wide distribution of C. simplex throughout the range of distribution of snakes of the genus Vipera. PMID:9269719

Modrý, D; Koudela, B; Volf, J; Necas, P; Hudcovic, T

1997-01-01

19

A new species of hognose pitviper, genus Porthidium, from the southwestern Pacific of Costa Rica (Serpentes: Viperidae).  

PubMed

A new species of terrestrial pitviper, Porthidium porrasi, is described from mesophytic forests of the Península de Osa and surrounding area of the Pacific versant of southwestern Costa Rica. It is most similar to P. nasutum and is characterized by a pattern of bands, persistence of the juvenile tail color in adults, and a high number of dorsal scales. Analysis of mtDNA sequences confirms its distinction from P. nasutum. The existence of this species reinforces the notion of elevated herpetofaunal endemism in southwestern Costa Rica. PMID:15162788

Lamar, William W; Sasa, Mahmood

2003-01-01

20

Appraisal of Antiophidic Potential of Marine Sponges against Bothrops jararaca and Lachesis muta Venom  

PubMed Central

Snakebites are a health problem in many countries due to the high incidence of such accidents. Antivenom treatment has regularly been used for more than a century, however, this does not neutralize tissue damage and may even increase the severity and morbidity of accidents. Thus, it has been relevant to search for new strategies to improve antiserum therapy, and a variety of molecules from natural sources with antiophidian properties have been reported. In this paper, we analyzed the ability of ten extracts from marine sponges (Amphimedon viridis, Aplysina fulva, Chondrosia collectrix, Desmapsamma anchorata, Dysidea etheria, Hymeniacidon heliophila, Mycale angulosa, Petromica citrina, Polymastia janeirensis, and Tedania ignis) to inhibit the effects caused by Bothrops jararaca and Lachesis muta venom. All sponge extracts inhibited proteolysis and hemolysis induced by both snake venoms, except H. heliophila, which failed to inhibit any biological activity. P. citrina inhibited lethality, hemorrhage, plasma clotting, and hemolysis induced by B. jararaca or L. muta. Moreover, other sponges inhibited hemorrhage induced only by B. jararaca. We conclude that Brazilian sponges may be a useful aid in the treatment of snakebites caused by L. muta and B. jararaca and therefore have potential for the discovery of molecules with antiophidian properties. PMID:24141284

Faioli, Camila Nunes; Domingos, Thaisa Francielle Souza; de Oliveira, Eduardo Coriolano; Sanchez, Eládio Flores; Ribeiro, Suzi; Muricy, Guilherme; Fuly, Andre Lopes

2013-01-01

21

Burnup calculation methodology in the serpent 2 Monte Carlo code  

SciTech Connect

This paper presents two topics related to the burnup calculation capabilities in the Serpent 2 Monte Carlo code: advanced time-integration methods and improved memory management, accomplished by the use of different optimization modes. The development of the introduced methods is an important part of re-writing the Serpent source code, carried out for the purpose of extending the burnup calculation capabilities from 2D assembly-level calculations to large 3D reactor-scale problems. The progress is demonstrated by repeating a PWR test case, originally carried out in 2009 for the validation of the newly-implemented burnup calculation routines in Serpent 1. (authors)

Leppaenen, J. [VTT Technical Research Centre of Finland, P.O.Box 1000, FI-02044 VTT (Finland); Isotalo, A. [Aalto Univ., Dept. of Applied Physics, P.O.Box 14100, FI-00076 AALTO (Finland)

2012-07-01

22

A Dream of Serpents Taking Down the Gang That Sold College Degrees, Hijacked an  

E-print Network

A Dream of Serpents Taking Down the Gang That Sold College Degrees, Hijacked an Embassy, and Bought, be a bystander. --Yehuda Bauer © 2012 George Gollin #12;2 George Gollin A Dream of Serpents Taking Down the Gang

Gollin, George

23

A Transcriptomic View of the Proteome Variability of Newborn and Adult Bothrops jararaca Snake Venoms  

PubMed Central

Background Snake bite is a neglected public health problem in communities in rural areas of several countries. Bothrops jararaca causes many snake bites in Brazil and previous studies have demonstrated that the pharmacological activities displayed by its venom undergo a significant ontogenetic shift. Similarly, the venom proteome of B. jararaca exhibits a considerable variation upon neonate to adult transition, which is associated with changes in diet from ectothermic prey in early life to endothermic prey in adulthood. Moreover, it has been shown that the Brazilian commercial antibothropic antivenom, which is produced by immunization with adult venom, is less effective in neutralizing newborn venom effects. On the other hand, venom gland transcripts of newborn snakes are poorly known since all transcriptomic studies have been carried out using mRNA from adult specimens. Methods/Principal Findings Here we analyzed venom gland cDNA libraries of newborn and adult B. jararaca in order to evaluate whether the variability demonstrated for its venom proteome and pharmacological activities was correlated with differences in the structure of toxin transcripts. The analysis revealed that the variability in B. jararaca venom gland transcriptomes is quantitative, as illustrated by the very high content of metalloproteinases in the newborn venom glands. Moreover, the variability is also characterized by the structural diversity of SVMP precursors found in newborn and adult transcriptomes. In the adult transcriptome, however, the content of metalloproteinase precursors considerably diminishes and the number of transcripts of serine proteinases, C-type lectins and bradykinin-potentiating peptides increase. Moreover, the comparison of the content of ESTs encoding toxins in adult male and female venom glands showed some gender-related differences. Conclusions/Significance We demonstrate a substantial shift in toxin transcripts upon snake development and a marked decrease in the metalloproteinase P-III/P-I class ratio which are correlated with changes in the venom proteome complexity and pharmacological activities. PMID:22428077

Zelanis, André; Andrade-Silva, Débora; Rocha, Marisa M.; Furtado, Maria F.; Serrano, Solange M. T.; Junqueira-de-Azevedo, Inácio L. M.; Ho, Paulo Lee

2012-01-01

24

Proteomic Analysis of the Ontogenetic Variability in Plasma Composition of Juvenile and Adult Bothrops jararaca Snakes  

PubMed Central

The ontogenetic variability in venom composition of some snake genera, including Bothrops, as well as the biological implications of such variability and the search of new molecules that can neutralize the toxic components of these venoms have been the subject of many studies. Thus, considering the resistance of Bothrops jararaca to the toxic action of its own venom and the ontogenetic variability in venom composition described in this species, a comparative study of the plasma composition of juvenile and adult B. jararaca snakes was performed through a proteomic approach based on 2D electrophoresis and mass spectrometry, which allowed the identification of proteins that might be present at different levels during ontogenetic development. Among the proteins identified by mass spectrometry, antihemorrhagic factor Bj46a was found only in adult plasma. Moreover, two spots identified as phospholipase A2 inhibitors were significantly increased in juvenile plasma, which can be related to the higher catalytic PLA2 activity shown by juvenile venom in comparison to that of adult snakes. This work shows the ontogenetic variability of B. jararaca plasma, and that these changes can be related to the ontogenetic variability described in its venom. PMID:24062950

de Morais-Zani, Karen; Grego, Kathleen Fernandes; Tanaka, Aparecida Sadae; Tanaka-Azevedo, Anita Mitico

2013-01-01

25

Depletion of Plasma Albumin for Proteomic Analysis of Bothrops jararaca Snake Plasma  

PubMed Central

The proteomic analysis of plasma samples represents a challenge as a result of the presence of highly abundant proteins such as albumin. To enable the detection of biomarkers, which are commonly low-abundance proteins, in complex blood fluids, it is necessary to remove high-abundance proteins efficiently. Moreover, there is a range of about 10 orders of magnitude for the abundance of different protein species in serum. Here, we describe for the first time a study of reptilian albumin depletion using resins usually used in mammalian plasma depletion procedures. We performed the depletion of albumin from Bothrops jaraca plasma using the HiTrap Blue high-performance column (GE Healthcare Life Sciences, Piscataway, NJ, USA) and the kit Albumin & IgG Depletion SpinTrap column (GE Healthcare Life Sciences). In addition, proteomic approaches were used to analyze reptilian plasma. Our results showed that B. jararaca albumin bound to both columns, but those interactions were not enough to remove a large amount of albumin to reach an enrichment of low-abundance proteins. Although the depletion techniques used in this work were not the best to remove B. jararaca plasma albumin, our present work highlights the similarity between B. jararaca and mammalian albumin, contributing to the knowledge of comparative hemostatic proteins. PMID:21738439

de Morais-Zani, Karen; Grego, Kathleen Fernandes; Tanaka, Aparecida Sadae; Tanaka-Azevedo, Anita Mitico

2011-01-01

26

Antigenic, microbicidal and antiparasitic properties of an l-amino acid oxidase isolated from Bothrops jararaca snake venom.  

PubMed

Venoms from the bee Apis mellifera, the caterpillar Lonomia achelous, the spiders Lycosa sp. and Phoneutria nigriventer, the scorpions Tityus bahiensis and Tityus serrulatus, and the snakes Bothrops alternatus, Bothrops jararaca, Bothrops jararacussu, Bothrops moojeni, Bothrops neuwiedi, Crotalus durissus terrificus, and Lachesis muta were assayed (800mug/mL) for activity against Staphylococcus aureus. Venoms from B. jararaca and B. jararacussu showed the highest S. aureus growth inhibition and also against other Gram-positive and Gram-negative bacteria. To characterize the microbicidal component(s) produced by B. jararaca, venom was fractionated through gel exclusion chromatography. The high molecular weight, anti-S. aureus P1 fraction was further resolved by anion exchange chromatography through Mono Q columns using a 0-0.5M NaCl gradient. Bactericidal Mono Q fractions P5 and P6 showed significant LAAO activity using l-leucine as substrate. These fractions were pooled and subjected to Heparin affinity chromatography, which rendered a single LAAO activity peak. The anti-S. aureus activity was abolished by catalase, suggesting that the effect is dependent on H(2)O(2) production. SDS-PAGE of isolated LAAO indicated the presence of three isoforms since deglycosylation with a recombinant N-glycanase rendered a single 38.2 kDa component. B. jararaca LAAO specific activity was 142.7 U/mg, based on the oxidation of l-leucine. The correlation between in vivo neutralization of lethal toxicity (ED(50)) and levels of horse therapeutic antibodies anti-LAAO measured by ELISA was investigated to predict the potency of Brazilian antibothropic antivenoms. Six horses were hyperimmunized with Bothrops venoms (50% from B. jararaca and 12.5% each from B. alternatus, B. jararacussu, B. neuwiedii and B. moojeni). To set up an indirect ELISA, B. jararaca LAAO and crude venom were used as antigens. Correlation coefficients (r) between ED(50) and ELISA antibody titers against B. jararaca venom and LAAO were 0.846 (p<0.001) and 0.747 (p<0.001), respectively. The hemolytic and leishmanicidal (anti-Leishmania amazonensis) activity of LAAO was also determined. PMID:19101583

Ciscotto, P; Machado de Avila, R A; Coelho, E A F; Oliveira, J; Diniz, C G; Farías, L M; de Carvalho, M A R; Maria, W S; Sanchez, E F; Borges, A; Chávez-Olórtegui, C

2009-03-01

27

Generation of SFR few-group constants using the Monte Carlo code Serpent  

SciTech Connect

In this study, the Serpent Monte Carlo code was used as a tool for preparation of homogenized few-group cross sections for the nodal diffusion analysis of Sodium cooled Fast Reactor (SFR) cores. Few-group constants for two reference SFR cores were generated by Serpent and then employed by nodal diffusion code DYN3D in 2D full core calculations. The DYN3D results were verified against the references full core Serpent Monte Carlo solutions. A good agreement between the reference Monte Carlo and nodal diffusion results was observed demonstrating the feasibility of using Serpent for generation of few-group constants for the deterministic SFR analysis. (authors)

Fridman, E.; Rachamin, R. [Helmholz-Zentrum Dresden-Rossendorf, POB 510119, Dresden, 01314 (Germany); Shwageraus, E. [Ben-Gurion University, POB 653, 84105 Beer-Sheva (Israel)

2013-07-01

28

The defensive strike of five species of lanceheads of the genus Bothrops (Viperidae).  

PubMed

We studied the defensive strike of one species of each of five recognized lineages within the genus Bothrops, namely, B. alternatus, B. jararaca, B. jararacussu, B. moojeni and B. pauloensis. The defensive strike of the studied species was in general similar to that of Crotalus viridis and C. atrox, but some important differences were observed. Bothrops alternatus and B. pauloensis struck preferentially from a tight body posture, whereas B. jararaca and B. moojeni from a loose body posture. Defensive strikes were either true or false (during the latter, the mouth remains closed or partially open). Almost all strikes were successful; only on a few occasions snakes missed their target (flawed strikes). Strike variables were very conservative among the five species, especially strike distance and height, and one possible explanation may be related to constraints imposed on strike variables as a way of increasing strike accuracy. PMID:17876444

Araújo, M S; Martins, M

2007-05-01

29

Winter profile of plasma sex steroid levels in free-living male western diamond-backed rattlesnakes, Crotalus atrox (Serpentes: Viperidae).  

PubMed

Recent field studies on the reproductive ecology of western diamond-backed rattlesnakes (Crotalus atrox) from populations in southern Arizona showed significant differences in the concentration of plasma sex steroids (testosterone, T; 5alpha-dihydrotestosterone, DHT; and 17beta-estradiol, E2) throughout the active season (March-October), and peak levels were coincident with the two mating periods (late summer and early spring). There is, however, no information on levels of sex steroids during winter. Similar to most snakes, hibernating individuals of C. atrox are typically inaccessible, but in southern Arizona, where environmental conditions are typically mild during winter, adult males frequently bask at or near the entrances of communal dens. Basking activity, therefore, offers a unique logistical opportunity to assess the complete annual profile of plasma sex steroid levels in males of a temperate reptile in nature. From November to February, we measured levels of plasma T, DHT, and E2 in adult male C. atrox that were located basking at communal dens. Additionally, cloacal, core body, and ambient air temperatures were obtained to investigate potential relationships between body temperatures and levels of sex steroids. Mean levels of T, DHT, and E2 were relatively high, and the concentration hierarchy was T>DHT>E2. Mean levels of T, DHT, and E2 showed no significant variation across the four months of sampling; however, E2 levels decreased progressively. In the annul cycle, sex steroid levels during winter were not basal when compared to values obtained during the active season. Mean cloacal temperatures of basking males were significantly higher than core body temperatures of non-basking males (inside dens) from November-December, and in February, which suggests that one function of winter basking is to elevate body temperatures. Steroid levels, nonetheless, were not significantly correlated with cloacal temperatures. We suggest that future field studies of male C. atrox should: (a) investigate sex steroid levels in non-basking individuals and (b) test whether elevated levels of sex steroids during winter facilitate the large increases that occur in early spring, which are coincident with the second mating season. Our findings on the reproductive biology of C. atrox and other viperids are discussed in the context of the associated-dissociated model of reproduction. PMID:16828091

Schuett, Gordon W; Repp, Roger A; Taylor, Emily N; DeNardo, Dale F; Earley, Ryan L; Van Kirk, Edward A; Murdoch, William J

2006-10-01

30

Functional and histopathological renal changes induced in rats by Bothrops jararaca venom.  

PubMed

1. Ninety-eight adult female rats were injected with 14 micrograms/g B. jararaca venom intraperitoneally to determine functional and histopathological renal changes. 2. Glomerular filtration rate, renal plasma flow, filtration fraction, osmolar clearance, water transportation in collecting ducts, urinary sodium excretion, fractional sodium excretion, albuminuria, urinalysis, plasma creatinine, urinary output and mean arterial pressure were studied before and 24 and 48 h after venom administration. Light microscope examination of the kidneys was carried out in another group of rats before and 2, 5 and 24 h after venom administration. 3. Treated animals developed acute renal failure characterized by a decrease in glomerular filtration rate, osmolar clearance, and fractional and urinary sodium excretion, and by an increase in plasma creatinine. There was also a decrease in renal plasma flow and mean arterial pressure. Histopathological examination of the kidneys indicated mild proliferation of the mesangial matrix and degenerative changes of the tubules characterized by loss of brush border and cytoplasmic vacuolation. 4. The hemodynamic changes probably played an important role in the pathogenesis of the functional and histopathologic renal changes developed by the animals after venom injection. PMID:2804475

Rezende, N A; Amaral, C F; Bambirra, E A; Lachatt, J J; Coimbra, T M

1989-01-01

31

Interpolations of nuclide-specific scattering kernels generated with Serpent  

SciTech Connect

The neutron group-to-group scattering cross section is an essential input parameter for any multi-energy group physics model. However, if the analyst prefers to use Monte Carlo transport to generate group constants this data is difficult to obtain for a single species of a material. Here, the Monte Carlo code Serpent was modified to return the group transfer probabilities on a per-nuclide basis. This ability is demonstrated in conjunction with an essential physics reactor model where cross section perturbations are used to dynamically generate reactor state dependent group constants via interpolation from pre-computed libraries. The modified version of Serpent was therefore verified with three interpolation cases designed to test the resilience of the interpolation scheme to changes in intra-group fluxes. For most species, interpolation resulted in errors of less than 5% of transport-computed values. For important scatterers, such as {sup 1}H, errors less than 2% were observed. For nuclides with high errors ( > 10%), the scattering channel typically only had a small probability of occurring. (authors)

Scopatz, A.; Schneider, E. [Univ. of Texas at Austin, 1 Univ. Station, C2200, Austin, TX 78712 (United States)

2012-07-01

32

The Serpent Monte Carlo Code: Status, Development and Applications in 2013  

NASA Astrophysics Data System (ADS)

The Serpent Monte Carlo reactor physics burnup calculation code has been developed at VTT Technical Research Centre of Finland since 2004, and is currently used in 100 universities and research organizations around the world. This paper presents the brief history of the project, together with the currently available methods and capabilities and plans for future work. Typical user applications are introduced in the form of a summary review on Serpent-related publications over the past few years.

Leppänen, Jaakko; Pusa, Maria; Viitanen, Tuomas; Valtavirta, Ville; Kaltiaisenaho, Toni

2014-06-01

33

Bothrops jararaca Venom Metalloproteinases Are Essential for Coagulopathy and Increase Plasma Tissue Factor Levels during Envenomation  

PubMed Central

Background/Aims Bleeding tendency, coagulopathy and platelet disorders are recurrent manifestations in snakebites occurring worldwide. We reasoned that by damaging tissues and/or activating cells at the site of the bite and systemically, snake venom toxins might release or decrypt tissue factor (TF), resulting in activation of blood coagulation and aggravation of the bleeding tendency. Thus, we addressed (a) whether TF and protein disulfide isomerase (PDI), an oxireductase involved in TF encryption/decryption, were altered in experimental snake envenomation; (b) the involvement and significance of snake venom metalloproteinases (SVMP) and serine proteinases (SVSP) to hemostatic disturbances. Methods/Principal Findings Crude Bothrops jararaca venom (BjV) was preincubated with Na2-EDTA or AEBSF, which are inhibitors of SVMP and SVSP, respectively, and injected subcutaneously or intravenously into rats to analyze the contribution of local lesion to the development of hemostatic disturbances. Samples of blood, lung and skin were collected and analyzed at 3 and 6 h. Platelet counts were markedly diminished in rats, and neither Na2-EDTA nor AEBSF could effectively abrogate this fall. However, Na2-EDTA markedly reduced plasma fibrinogen consumption and hemorrhage at the site of BjV inoculation. Na2-EDTA also abolished the marked elevation in TF levels in plasma at 3 and 6 h, by both administration routes. Moreover, increased TF activity was also noticed in lung and skin tissue samples at 6 h. However, factor VII levels did not decrease over time. PDI expression in skin was normal at 3 h, and downregulated at 6 h in all groups treated with BjV. Conclusions SVMP induce coagulopathy, hemorrhage and increased TF levels in plasma, but neither SVMP nor SVSP are directly involved in thrombocytopenia. High levels of TF in plasma and TF decryption occur during snake envenomation, like true disseminated intravascular coagulation syndrome, and might be implicated in engendering bleeding manifestations in severely-envenomed patients. PMID:24831016

Yamashita, Karine M.; Alves, André F.; Barbaro, Katia C.; Santoro, Marcelo L.

2014-01-01

34

A prothrombin activator from Bothrops erythromelas (jararaca-da-seca) snake venom: characterization and molecular cloning.  

PubMed Central

A novel prothrombin activator enzyme, which we have named 'berythractivase', was isolated from Bothrops erythromelas (jararaca-da-seca) snake venom. Berythractivase was purified by a single cation-exchange-chromatography step on a Resource S (Amersham Biosciences) column. The overall purification (31-fold) indicates that berythractivase comprises about 5% of the crude venom. It is a single-chain protein with a molecular mass of 78 kDa. SDS/PAGE of prothrombin after activation by berythractivase showed fragment patterns similar to those generated by group A prothrombin activators, which convert prothrombin into meizothrombin, independent of the prothrombinase complex. Chelating agents, such as EDTA and o -phenanthroline, rapidly inhibited the enzymic activity of berythractivase, like a typical metalloproteinase. Human fibrinogen A alpha-chain was slowly digested only after longer incubation with berythractivase, and no effect on the beta- or gamma-chains was observed. Berythractivase was also capable of triggering endothelial proinflammatory and procoagulant cell responses. von Willebrand factor was released, and the surface expression of both intracellular adhesion molecule-1 and E-selectin was up-regulated by berythractivase in cultured human umbilical-vein endothelial cells. The complete berythractivase cDNA was cloned from a B. erythromelas venom-gland cDNA library. The cDNA sequence possesses 2330 bp and encodes a preproprotein with significant sequence similarity to many other mature metalloproteinases reported from snake venoms. Berythractivase contains metalloproteinase, desintegrin-like and cysteine-rich domains. However, berythractivase did not elicit any haemorrhagic response. These results show that, although the primary structure of berythractivase is related to that of snake-venom haemorrhagic metalloproteinases and functionally similar to group A prothrombin activators, it is a prothrombin activator devoid of haemorrhagic activity. This is a feature not observed for most of the snake venom metalloproteinases, including the group A prothrombin activators. PMID:12225292

Silva, Márcia B; Schattner, Mirta; Ramos, Celso R R; Junqueira-de-Azevedo, Inácio L M; Guarnieri, Míriam C; Lazzari, María A; Sampaio, Claudio A M; Pozner, Roberto G; Ventura, Janaina S; Ho, Paulo L; Chudzinski-Tavassi, Ana M

2003-01-01

35

Cell adhesion molecules involved in the leukocyte recruitment induced by venom of the snake Bothrops jararaca.  

PubMed Central

It has been shown that Bothrops jararaca venom (BjV) induces a significant leukocyte accumulation, mainly neutrophils, at the local of tissue damage. Therefore, the role of the adhesion molecules intercellular adhesion molecule-1 (ICAM-1), LECAM-1, CD18, leukocyte function-associated antigen-1 (LFA-1) and platelet endothelial cell adhesion molecule-1 (PECAM-1) on the BjV-induced neutrophil accumulation and the correlation with release of LTB4, TXA2, tumor necrosis factor-alpha, interleukin (IL)-1 and IL-6 have been investigated. Anti-mouse LECAM-1, LFA-1, ICAM-1 and PECAM-1 monoclonal antibody injection resulted in a reduction of 42%, 80%, 66% and 67%, respectively, of neutrophil accumulation induced by BjV (250 microg/kg, intraperitoneal) injection in male mice compared with isotype-matched control injected animals. The anti-mouse CD18 monoclonal antibody had no significant effect on venom-induced neutrophil accumulation. Concentrations of LTB(4), TXA(2), IL-6 and TNF-alpha were significant increased in the peritoneal exudates of animals injected with venom, whereas no increment in IL-1 was detected. This results suggest that ICAM-1, LECAM-1, LFA-1 and PECAM-1, but not CD18, adhesion molecules are involved in the recruitment of neutrophils into the inflammatory site induced by BjV. This is the first in vivo evidence that snake venom is able to up-regulate the expression of adhesion molecules by both leukocytes and endothelial cells. This venom effect may be indirect, probably through the release of the inflammatory mediators evidenced in the present study. PMID:12581499

Zamuner, Stella R; Teixeira, Catarina F P

2002-01-01

36

Comparison of Serpent and HELIOS-2 as applied for the PWR few-group cross section generation  

SciTech Connect

This paper discusses recent modifications to the Serpent Monte Carlo code methodology and related to the calculation of few-group diffusion coefficients and reflector discontinuity factors The new methods were assessed in the following manner. First, few-group homogenized cross sections calculated by Serpent for a reference PWR core were compared with those generated 1 commercial deterministic lattice transport code HELIOS-2. Second, Serpent and HELIOS-2 fe group cross section sets were later employed by nodal diffusion code DYN3D for the modeling the reference PWR core. Finally, the nodal diffusion results obtained using the both cross section sets were compared with the full core Serpent Monte Carlo solution. The test calculations show that Serpent can calculate the parameters required for nodal analyses similar to conventional deterministic lattice codes. (authors)

Fridman, E. [Helmholz-Zentrum Dresden-Rossendorf, POB 51 01 19, Dresden, 01314 (Germany); Leppaenen, J. [VTT Technical Research Centre of Finland, POB 1000, FI-02044 VTT (Finland); Wemple, C. [Studsvik Scandpower, Inc., 504 Shoup Ave., Idaho Falls, ID (United States)

2013-07-01

37

Characterization of a Paramyxovirus from a Fer de Lance viper (Bothrops jararaca): partial nucleotide sequence of the putative fusion protein.  

PubMed

During the generation of Expressed Sequence Tags (ESTs) from the Fer de Lance viper (Bothrops jararaca) venom glands, a partial cDNA (clone H8) coding for a protein with all the features of a paramyxovirus fusion protein was characterized. It has 920 bp and codes for a partial protein of 279 amino acids. Two potential N-glycosylation sites are present in the sequence which also possesses a typical membrane anchoring domain made of a stretch of hydrophobic amino acids. The polyadenylation signal sequence was identified. When compared to other fusion proteins, it showed the highest sequence similarity (37-39%) with those of human parainfluenza 3 and Sendai virus. PMID:11266217

Junqueira de Azevedo, I L; Prieto da Silva, A R; Carmona, E; Ho, P L

2001-01-01

38

Development of a dynamic simulation mode in Serpent 2 Monte Carlo code  

SciTech Connect

This paper presents a dynamic neutron transport mode, currently being implemented in the Serpent 2 Monte Carlo code for the purpose of simulating short reactivity transients with temperature feedback. The transport routine is introduced and validated by comparison to MCNP5 calculations. The method is also tested in combination with an internal temperature feedback module, which forms the inner part of a multi-physics coupling scheme in Serpent 2. The demo case for the coupled calculation is a reactivity-initiated accident (RIA) in PWR fuel. (authors)

Leppaenen, J. [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT (Finland)

2013-07-01

39

Aqueous Leaf Extract of Jatropha gossypiifolia L. (Euphorbiaceae) Inhibits Enzymatic and Biological Actions of Bothrops jararaca Snake Venom  

PubMed Central

Snakebites are a serious public health problem due their high morbi-mortality. The main available specific treatment is the antivenom serum therapy, which has some disadvantages, such as poor neutralization of local effects, risk of immunological reactions, high cost and difficult access in some regions. In this context, the search for alternative therapies is relevant. Therefore, the aim of this study was to evaluate the antiophidic properties of Jatropha gossypiifolia, a medicinal plant used in folk medicine to treat snakebites. The aqueous leaf extract of the plant was prepared by decoction and phytochemical analysis revealed the presence of sugars, alkaloids, flavonoids, tannins, terpenes and/or steroids and proteins. The extract was able to inhibit enzymatic and biologic activities induced by Bothrops jararaca snake venom in vitro and in vivo. The blood incoagulability was efficiently inhibited by the extract by oral route. The hemorrhagic and edematogenic local effects were also inhibited, the former by up to 56% and the latter by 100%, in animals treated with extract by oral and intraperitoneal routes, respectively. The inhibition of myotoxic action of B. jararaca reached almost 100%. According to enzymatic tests performed, it is possible to suggest that the antiophidic activity may be due an inhibitory action upon snake venom metalloproteinases (SVMPs) and/or serine proteinases (SVSPs), including fibrinogenolytic enzymes, clotting factors activators and thrombin like enzymes (SVTLEs), as well upon catalytically inactive phospholipases A2 (Lys49 PLA2). Anti-inflammatory activity, at least partially, could also be related to the inhibition of local effects. Additionally, protein precipitating and antioxidant activities may also be important features contributing to the activity presented. In conclusion, the results demonstrate the potential antiophidic activity of J. gossypiifolia extract, including its significant action upon local effects, suggesting that it may be used as a new source of bioactive molecules against bothropic venom. PMID:25126759

Félix-Silva, Juliana; Souza, Thiago; Menezes, Yamara A. S.; Cabral, Bárbara; Câmara, Rafael B. G.; Silva-Junior, Arnóbio A.; Rocha, Hugo A. O.; Rebecchi, Ivanise M. M.; Zucolotto, Silvana M.; Fernandes-Pedrosa, Matheus F.

2014-01-01

40

The effect of jararhagin, a metalloproteinase from Bothrops jararaca venom, on pro-inflammatory cytokines released by murine peritoneal adherent cells  

Microsoft Academic Search

The release of pro-inflammatory cytokines (IL-1?, IL-6 and TNF-?) from murine peritoneal adherent cells (MPAC) was studied after exposure to jararhagin, a metalloproteinase\\/disintegrin isolated from Bothrops jararaca venom. MPACs were treated with LPS (lipopolysaccharide), jararhagin, or EDTA-inactivated jararhagin for up to 24h. Following incubation, the culture supernatant was assayed by ELISA for the presence of cytokines, while the cells were

Patricia B. Clissa; Gavin D. Laing; R. David G. Theakston; Ivan Mota; Mark J. Taylor; Ana M. Moura-da-Silva

2001-01-01

41

Neutralization of the oedematogenic activity of Bothrops Jararaca venom on the mouse paw by an antibothropic fraction isolated from Opossum (Didelphis Marsupialis) serum  

Microsoft Academic Search

The pharmacological modulation of mice paw oedema produced byBothrops jararaca venom (BJV) has been studied. Intraplantar injection of BJV (1–30 ?g\\/paw) produced a dose-and time-related oedema, which was maximal 30 min after injection, reduced gradually thereafter and disappeared over 48h. BJV heated at 100°C for 5 or 15 min blocked local hemorrhage and caused partial inhibition of its oedematogenic activity.

Jonas Perales; Claudia Z. Amorim; Surza L. G. Rocha; Gilberto B. Domont; Haity Moussatché

1992-01-01

42

The Bradykinin-potentiating peptides from venom gland and brain of Bothrops jararaca contain highly site specific inhibitors of the somatic angiotensin-converting enzyme.  

PubMed

Pyroglutamyl, proline-rich oligopeptides, classically referred to as bradykinin-potentiating peptides (BPPs) are found in Bothrops jararaca venom, and are naturally occurring inhibitors of the somatic angiotensin-converting enzyme (ACE). The chemical and pharmacological properties of these peptides were essential for the development of captopril, the first active site directed inhibitor of ACE, currently used to treat human hypertension. ACE is a complex ectoenzyme of the vascular endothelium, possessing two catalytic sites, performing diverse specific roles. Recent advances concerning novel features of BPPs revealed that they might still contribute to a better understanding of the cardiovascular physiology and pathology. The molecular biology of the BPPs revealed that they are part of two distinct C-type natriuretic peptide precursors found in the venom gland and the brain of B. jararaca, each containing seven BPPs. In situ hybridization studies detected the presence of the corresponding mRNA precursor in snake brain regions correlated with neuroendocrine functions, such as the ventro-medial hypothalamus, the paraventricular nuclei, the paraventricular organ, and the subcommissural organ. In this article we discuss the large variety of homologous BPPs in B. jararaca venom and brain, its significance, and whether the BPPs could represent novel endogenous neuropeptides. PMID:15922781

Hayashi, Mirian A F; Camargo, Antonio C M

2005-06-15

43

Mitochondrial DNA-Based Phylogeography of North American Rubber Boas, Charina bottae (Serpentes: Boidae)  

E-print Network

Mitochondrial DNA-Based Phylogeography of North American Rubber Boas, Charina bottae (Serpentes the phylogeography of Charina bottae (rubber boa) in western North America, with an emphasis on populations from). Charina bottae (rubber boa) is widespread in west- ern North America, ranging from southwestern Can- ada

Rodríguez, Javier A.

44

Lachesis muta (Viperidae) cDNAs Reveal Diverging Pit Viper Molecules and Scaffolds Typical of Cobra (Elapidae) Venoms: Implications for Snake Toxin Repertoire Evolution  

PubMed Central

Efforts to describe toxins from the two major families of venomous snakes (Viperidae and Elapidae) usually reveal proteins belonging to few structural types, particular of each family. Here we carried on an effort to determine uncommon cDNAs that represent possible new toxins from Lachesis muta (Viperidae). In addition to nine classes of typical toxins, atypical molecules never observed in the hundreds of Viperidae snakes studied so far are highly expressed: a diverging C-type lectin that is related to Viperidae toxins but appears to be independently originated; an ohanin-like toxin, which would be the third member of the most recently described class of Elapidae toxins, related to human butyrophilin and B30.2 proteins; and a 3FTx-like toxin, a new member of the widely studied three-finger family of proteins, which includes major Elapidae neurotoxins and CD59 antigen. The presence of these common and uncommon molecules suggests that the repertoire of toxins could be more conserved between families than has been considered, and their features indicate a dynamic process of venom evolution through molecular mechanisms, such as multiple recruitments of important scaffolds and domain exchange between paralogs, always keeping a minimalist nature in most toxin structures in opposition to their nontoxin counterparts. PMID:16582429

Junqueira-de-Azevedo, Inácio L. M.; Ching, Ana T. C.; Carvalho, Eneas; Faria, Fernanda; Nishiyama, Milton Y.; Ho, Paulo L.; Diniz, Marcelo R. V.

2006-01-01

45

SERPent: Automated reduction and RFI-mitigation software for e-MERLIN  

NASA Astrophysics Data System (ADS)

The Scripted E-merlin Rfi-mitigation PipelinE for iNTerferometry (SERPent) is an automated reduction and RFI-mitigation procedure utilising the SumThreshold methodology (Offringa et al., 2010a), originally developed for the LOFAR pipeline. SERPent is written in the Parseltongue language enabling interaction with the Astronomical Image Processing Software (AIPS) program. Moreover, SERPent is a simple 'out of the box' Python script, which is easy to set up and is free of compilers. In addition to the flagging of RFI affected visibilities, the script also flags antenna zero-amplitude dropouts and Lovell telescope phase calibrator stationary scans inherent to the e-MERLIN system. Both the flagging and computational performances of SERPent are presented here, for e-MERLIN commissioning datasets for both L-band (1.3-1.8 GHz) and C-band (4-8 GHz) observations. RFI typically amounts to <20%-25% for the more problematic L-band observations and <5% for the generally RFI quieter C-band. The level of RFI detection and flagging is more accurate and delicate than visual manual flagging, with the output immediately ready for AIPS calibration. SERPent is fully parallelised and has been tested on a range of computing systems. The current flagging rate is at 110 GB day-1 on a 'high-end' computer (16 CPUs, 100 GB memory) which amounts to ˜6.9 GB CPU-1 day-1, with an expected increase in performance when e-MERLIN has completed its commissioning. The refining of automated reduction and calibration procedures is essential for the e-MERLIN legacy projects and future interferometers such as the SKA and the associated pathfinders (MeerKAT and ASKAP), where the vast data sizes (>TB) make traditional astronomer interactions unfeasible.

Peck, Luke W.; Fenech, Danielle M.

2013-08-01

46

Revised methods for few-group cross sections generation in the Serpent Monte Carlo code  

SciTech Connect

This paper presents new calculation methods, recently implemented in the Serpent Monte Carlo code, and related to the production of homogenized few-group constants for deterministic 3D core analysis. The new methods fall under three topics: 1) Improved treatment of neutron-multiplying scattering reactions, 2) Group constant generation in reflectors and other non-fissile regions and 3) Homogenization in leakage-corrected criticality spectrum. The methodology is demonstrated by a numerical example, comparing a deterministic nodal diffusion calculation using Serpent-generated cross sections to a reference full-core Monte Carlo simulation. It is concluded that the new methodology improves the results of the deterministic calculation, and paves the way for Monte Carlo based group constant generation. (authors)

Fridman, E. [Reactor Safety Div., Helmholz-Zentrum Dresden-Rossendorf, POB 51 01 19, Dresden, 01314 (Germany); Leppaenen, J. [VTT Technical Research Centre of Finland, POB 1000, FI-02044 VTT (Finland)

2012-07-01

47

Discovery of microscopic evidence for shock metamorphism at the Serpent Mound structure, south-central Ohio: confirmation of an origin by impact  

Microsoft Academic Search

The origin of the Serpent Mound structure in south-central Ohio has been disputed for many years. Clearly, more evidence was needed to resolve the confusion concerning the origin of the Serpent Mound feature either by endogenic processes or by hypervelocity impact. A petrographic study of 21 samples taken from a core 903 m long drilled in the central uplift of

Richard W. Carlton; Christian Koeberl; Mark T. Baranoski; Gregory A. Schumacher

1998-01-01

48

Type specimens of Crotalus scutulatus (Chordata: Reptilia: Squamata: Viperidae) re-examined, with new evidence after more than a century of confusion  

USGS Publications Warehouse

The original description of Crotalus scutulatus (Chordata: Reptilia: Squamata: Viperidae) was published in 1861 by Robert Kennicott, who did not identify a type specimen or a type locality. We review the history of specimens purported to be the type(s) and various designations of type locality. We provide evidence that ANSP 7069 (formerly one of two specimens of USNM 5027) is the holotype and that the appropriate type locality is Fort Buchanan, near present-day Sonoita, in Santa Cruz County, Arizona.

Cardwell, Michael D.; Gotte, Steve W.; McDiarmid, Roy W.; Gilmore, Ned; Poindexter, James A.

2013-01-01

49

An alternative micromethod to access the procoagulant activity of Bothrops jararaca venom and the efficacy of antivenom.  

PubMed

The assessment of the capacity of antivenoms to neutralize the lethal activity of snake venoms still relies largely on traditional rodent lethality assay (LD50). However, adequately validated in vitro tests should be introduced for assessing antivenom neutralizing capacity in plasma of immunized horses as well as for in-process quality control. The dynamic of fibrin formation in recalcified avian plasma samples is extremely slow, when compared to that presented by mammalian plasmas. In this study, we present one new coagulant assay, by performing dose-response curve after plotting the clotting time (CT) parameter of the ROTEM profile of recalcified chicken plasma samples (target) against semi-logarithmic doses of Bothrops jararaca venom (agonist), either in absence or in presence of the semi-logarithmic doses of anti-bothropic serum (ABS) (antagonist). The mean coagulant dose 50% (CD50) was defined as the quantity of venom (in ?g) which reduces CT to 900 s, between minimum and maximum responses. The CT induced by 5CD50 of the venom was used as the control for calculating the effective dose (ED) of each batch of ABS. ED was defined as the ABS dose (nanoliters, nL) at which CT induced by one amount of venom corresponding to 5CD50 is displaced to the maximum threshold (1800 s). Five batches of the ABS, previously assayed for their lethality neutralizing activity (ED50) were assayed. The correlation coefficient (r) between both in vitro (ED) and in vivo (ED50) values was 0.87 (p value < 0.05). We propose this micro method as highly sensitive for characterization and quantification of possible procoagulant activity of small doses of snake venoms (nanograms) and for detecting small doses (nanoliters) of specific antibodies against this effect in little volume samples of biological fluids. PMID:25128708

Oguiura, N; Kapronezai, J; Ribeiro, T; Rocha, M M T; Medeiros, C R; Marcelino, J R; Prezoto, B C

2014-11-01

50

Developing serpent-type wave generators to create solitary wave simulations with BEM  

NASA Astrophysics Data System (ADS)

Developing serpent-type wave generators to generate solitary waves in a 3D-basin was investigated in this study. Based on the Lagrangian description with time-marching procedures and finite differences of the time derivative, a 3D multiple directional wave basin with multidirectional piston wave generators was developed to simulate ocean waves by using BEM with quadrilateral elements, and to simulate wave-caused problems with fully nonlinear water surface conditions. The simulations of perpendicular solitary waves were conducted in the first instance to verify this scheme. Furthermore, the comparison of the waveform variations confirms that the estimation of 3D solitary waves is a feasible scheme.

Weng, Wen-Kai; Shih, Ruey-Syan; Chou, Chung-Ren

2013-10-01

51

Phospholipases a2 from Viperidae snakes: Differences in membranotropic activity between enzymatically active toxin and its inactive isoforms.  

PubMed

We describe the interaction of various phospholipases A2 (PLA2) from snake venoms of the family Viperidae (Macrovipera lebetina obtusa, Vipera ursinii renardi, Bothrops asper) with giant unilamellar vesicles (GUVs) composed of natural brain phospholipids mixture, visualized through fluorescence microscopy. The membrane fluorescent probes 8-anilino-1-naphthalenesulfonicacid (ANS), LAUDRAN and PRODAN were used to assess the state of the membrane and specifically mark the lipid packing and membrane fluidity. Our results have shown that the three PLA2s which contain either of aspartic acid, serine, or lysine residues at position 49 in the catalytic center, have different effects on the vesicles. The PLA2 with aspartic acid at this position causes the oval deformation of the vesicles, while serine and lysine-containing enzymes lead to an appreciable increase of fluorescence intensity in the vesicles membrane, wherein the shape and dimensions of GUVs have not changed, but in this case GUV aggregation occurs. LAURDAN and PRODAN detect the extent of water penetration into the bilayer surface. We calculated generalized polarization function (GP), showing that for all cases (D49 PLA2, S49 PLA2 and K49 PLA2) both LAUDRAN and PRODAN GP values decrease. A higher LAURDAN GP is indicative of low water penetration in the lipid bilayer in case of K49 PLA2 compared with D49 PLA2, whereas the PRODAN mainly gives information when lipid is in liquid crystalline phase. PMID:25450350

Ghazaryan, Narine A; Ghulikyan, Lusine; Kishmiryan, Arsen; Andreeva, Tatyana V; Utkin, Yuri N; Tsetlin, Victor I; Lomonte, Bruno; Ayvazyan, Naira M

2015-02-01

52

Avian pox infection in a free-living crested serpent eagle (Spilornis cheela) in southern Taiwan.  

PubMed

Avian pox viruses (APVs) have been reported to cause infection in diverse avian species worldwide. Herein we report the first case of APV infection in a free-living bird, a subadult crested serpent eagle (Spilornis cheela), in Taiwan. In addition to the typical wart-like lesions distributed on the cere, eyelid, and face, there were also yellowish nodules below the tongue and on the hard palate. Phylogenetic analysis of the 4b core protein gene showed that the APV is very close to that found in white-tailed sea eagle (Haliaeetus albicilla) in Japan recently. Because both cases are located on the same major flyway for migratory birds, the impact of this virus with regard to the wild and migratory raptor species along the East Asian-Australasian Flyway and West Pacific Flyway requires immediate investigation. PMID:21500652

Chen, C C; Pei, K J C; Lee, F R; Tzeng, M P; Chang, T C

2011-03-01

53

[Sequencing and analysis of the complete mitochondrial genome of the King Cobra, Ophiophagus hannah (Serpents: Elapidae)].  

PubMed

We obtained the complete mitochondrial genome of King Cobra(GenBank accession number: EU_921899) by Ex Taq-PCR, TA-cloning and primer-walking methods. This genome is very similar to other vertebrate, which is 17 267 bp in length and encodes 38 genes (including 13 protein-coding, 2 ribosomal RNA and 23 transfer RNA genes) and two long non-coding regions. The duplication of tRNA-Ile gene forms a new mitochondrial gene rearrangement model. Eight tRNA genes and one protein genes were transcribed from L strand, and the other genes were transcribed genes from H strand. Genes on the H strand show a fairly similar content of Adenosine and Thymine respectively, whereas those on the L strand have higher proportion of A than T. Combined rDNA sequence data (12S+16S rRNA) were used to reconstruct the phylogeny of 21 snake species for which complete mitochondrial genome sequences were available in the public databases. This large data set and an appropriate range of outgroup taxa demonstrated that Elapidae is more closely related to colubridae than viperidae, which supports the traditional viewpoints. PMID:20650853

Chen, Nian; Lai, Xiao-Ping

2010-07-01

54

Effects of N-acetyl-L-cysteine on redox status and markers of renal function in mice inoculated with Bothrops jararaca and Crotalus durissus terrificus venoms.  

PubMed

Renal dysfunction is an important aggravating factor in accidents caused by Crotalus durissus terrificus (Cdt) and Bothrops jararaca (Bj) bites. N-acetyl-l-cysteine (NAC) is well known as a nephroprotective antioxidant with low toxicity. The present study investigated the effects of NAC on redox status and markers of renal function in mice that received vehicle (controls) or venoms (v) of Cdt and Bj. In controls NAC promoted hypercreatinemia, hypouremia, hyperosmolality with decreased urea in urine, hyperproteinuria, decreased protein and increased dipeptidyl peptidase IV (DPPIV) in membrane-bound fraction (MF) from renal cortex (RC) and medulla (RM). NAC ameliorated or normalized altered creatinuria, proteinemia and aminopeptidase (AP) acid in MF, AP basic (APB) in soluble fraction (SF), and neutral AP in SF and MF from RC and RM in vBj envenomation. NAC ameliorated or normalized altered neutral AP in SF from RC and RM, and DPPIV and protein in MF from RC in vCdt envenomation. NAC ameliorated or restored renal redox status respectively in vCdt and vBj, and normalized uricemia in both envenomations. These data are promising perspectives that recommend the clinical evaluation of NAC as potential coadjuvant in the anti venom serotherapy for accidents with these snake's genera. PMID:24412461

Barone, Juliana Marton; Frezzatti, Rodrigo; Silveira, Paulo Flavio

2014-03-01

55

Purification, cloning, and molecular characterization of a high molecular weight hemorrhagic metalloprotease, jararhagin, from Bothrops jararaca venom. Insights into the disintegrin gene family.  

PubMed

A large hemorrhagin, jararhagin, has been cloned from a Bothrops jararaca venom gland cDNA expression library. The cDNA sequence predicts a 421-amino acid residue molecule with strong amino acid sequence homology and similar domain structure to HR1B, a high molecular weight hemorrhagic metalloprotease isolated from Trimeresurus flavoviridis (Habu) venom. Like HR1B, jararhagin contains enzyme, disintegrin, and cysteine-rich carboxyl-terminal regions. In the disintegrin region, the Arg-Gly-Asp sequence is replaced by Glu-Cys-Asp, as found in non-Arg-Gly-Asp disintegrin regions of HR1B and a guinea pig sperm fusion protein PH-30 beta. The cDNA sequence of jararhagin predicts a precursor protein (proprotein) with striking similarity to cryptic regions in precursors of the disintegrin peptides trigramin and rhodostomin. Comparison of jararhagin with disintegrin precursors highlights the modular arrangement of proprotein, metalloprotease, and disintegrin domains in the metalloprotease/disintegrin family and provides an insight into their biosynthesis and evolution. PMID:1385408

Paine, M J; Desmond, H P; Theakston, R D; Crampton, J M

1992-11-15

56

Bov-B long interspersed repeated DNA (LINE) sequences are present in Vipera ammodytes phospholipase A2 genes and in genomes of Viperidae snakes.  

PubMed

Ammodytin L is a myotoxic Ser49 phospholipase A2 (PLA2) homologue, which is tissue-specifically expressed in the venom glands of Vipera ammodytes. The complete DNA sequence of the gene and its 5' and 3' flanking regions has been determined. The gene consists of five exons separated by four introns. Comparative analysis of the ammodytin L and ammodytoxin C genes shows that all intron and flanking sequences are considerably more conserved (93-97%) than the mature protein-coding exons. The pattern of nucleotide substitutions in protein-coding exons is not random but occurs preferentially on the first and the second positions of codons, which suggests positive Darwinian evolution for a new function. An Ruminantia specific ART-2 retroposon, recently recognised as a 5'-truncated Bov-B long interspersed repeated DNA (LINE) sequence, was identified in the fourth intron of both genes. This result suggests that ammodytin L and ammodytoxin C genes are derived by duplication of a common ancestral gene. The phylogenetic distribution of Bov-B LINE among vertebrate classes shows that, besides the Ruminantia, it is limited to Viperidae snakes (Vipera ammodytes, Vipera palaestinae, Echis coloratus, Bothrops alternatus, Trimeresurus flavoviridis and Trimeresurus gramineus). The copy number of the 3' end of Bov-B LINE in the Vipera ammodytes genome is between 62,000 and 75,000. The absence of Bov-B LINE at orthologous positions in other snake PLA2 genes indicates that its retrotransposition in the V. ammodytes PLA2 gene locus has occurred quite recently, about 5 My ago. The amplification of Bov-B LINEs in snakes may have occurred before the divergence of the Viperinae and Crotalinae subfamilies. Due to its wide distribution in Viperidae snakes it may be a valuable phylogenetic marker. The neighbor-joining phylogenetic tree shows two clusters of truncated Bov-B LINE, a Bovidae and a snake cluster, indicating an early horizontal transfer of this transposable element. PMID:9219538

Kordis, D; Gubensek, F

1997-06-15

57

Characterization of a human coagulation factor Xa-binding site on Viperidae snake venom phospholipases A2 by affinity binding studies and molecular bioinformatics  

PubMed Central

Background The snake venom group IIA secreted phospholipases A2 (SVPLA2), present in the Viperidae snake family exhibit a wide range of toxic and pharmacological effects. They exert their different functions by catalyzing the hydrolysis of phospholipids (PL) at the membrane/water interface and by highly specific direct binding to: (i) presynaptic membrane-bound or intracellular receptors; (ii) natural PLA2-inhibitors from snake serum; and (iii) coagulation factors present in human blood. Results Using surface plasmon resonance (SPR) protein-protein interaction measurements and an in vitro biological test of inhibition of prothrombinase activity, we identify a number of Viperidae venom SVPLA2s that inhibit blood coagulation through direct binding to human blood coagulation factor Xa (FXa) via a non-catalytic, PL-independent mechanism. We classify the SVPLA2s in four groups, depending on the strength of their binding. Molecular electrostatic potentials calculated at the surface of 3D homology-modeling models show a correlation with inhibition of prothrombinase activity. In addition, molecular docking simulations between SVPLA2 and FXa guided by the experimental data identify the potential FXa binding site on the SVPLA2s. This site is composed of the following regions: helices A and B, the Ca2+ loop, the helix C-?-wing loop, and the C-terminal fragment. Some of the SVPLA2 binding site residues belong also to the interfacial binding site (IBS). The interface in FXa involves both, the light and heavy chains. Conclusion We have experimentally identified several strong FXa-binding SVPLA2s that disrupt the function of the coagulation cascade by interacting with FXa by the non-catalytic PL-independent mechanism. By theoretical methods we mapped the interaction sites on both, the SVPLA2s and FXa. Our findings may lead to the design of novel, non-competitive FXa inhibitors. PMID:18062812

Faure, Grazyna; Gowda, Veerabasappa T; Maroun, Rachid C

2007-01-01

58

Internal neutronics-temperature coupling in Serpent 2 - Reactivity differences resulting from choice of material property correlations  

SciTech Connect

This paper describes the unique way of simultaneously solving the power and temperature distributions of a nuclear system with the Monte Carlo neutron transport code Serpent 2. The coupled solution is achieved through the implementation of an internal temperature solver and material property correlations in the code. The program structure is reviewed concerning the temperature solver and the internal correlations as well as the internal coupling between these two and the neutron transport part. To estimate the reactivity differences resulting from correlation choices a simple pin-cell case has been calculated. It is established, that some correlation choices may result in difference in reactivity of approximately 100 pcm. (authors)

Valtavirta, V. [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT (Finland)

2013-07-01

59

2007 was an extremely busy year for the SERPENT project. We continued to carry out a high number of offshore missions, with  

E-print Network

. Large volumes of high-quality data have been collected, which is being used to improve our understanding that you enjoy reading these highlights from 2007. The SERPENT Team Cover picture: A stunning image from for food with a nearby soft coral, from the order Alcyonacida. #12;2 Contents 1 Foreword 2 Contents 3

National Oceanography Centre, Southampton

60

A Place of Transformation: Lessons from the Cosmic Serpent Informal Science Education Professional Development Project  

NASA Astrophysics Data System (ADS)

A cultural disconnect exists between Western scientists and educators and Native communities in terms of scientific worldviews and Indigenous ways of knowing. This cultural disconnect manifests itself in the lack of participation of Native Americans in Western science and a lack of appreciation by Western scientists of Native science. Our NSF-Funded project "Cosmic Serpent: Bridging Native and Western Learning in Museum Settings" set out to provide a way for informal science education practitioners and tribal museum practitioners to learn about these two worldviews in such a way as to inform their educational practice around these concepts. We began with a pilot workshop in year one of this four-year project. We then provided two week-long professional development workshops in three regions within the Western U.S., and culminated with a final conference for all participants. In total, the workshops served 162 participants, including 115 practitioners from 19 tribal museums and 41 science, natural history, and cultural museums; 23 tribal community members; and 24 "bridge people" with knowledge of both Indigenous and Western science. For this article, we focus on the professional and personal transformations around culture, knowledge, science, and worldviews that occurred as a part of this project. We evaluated the collaborative aspects of this grant between the Indigenous Education Institute; the Center for Science Education at the University of California, Berkeley; the Institute for Learning Innovation; Native Pathways; Association for Science and Technology Centers; and the National Museum of the American Indian. Using evaluation results, as well as our personal reflections, we share our learnings from a place of transformation. We provide lessons we learned with this project, which we hope others will find relevant to their own science education work.

Peticolas, L.; Maryboy, N.; Begay, D.; Stein, J.; Valdez, S.; Paglierani, R.

2012-08-01

61

Epidemiology of venomous and semi-venomous snakebites (Ophidia: Viperidae, Colubridae) in the Kashan city of the Isfahan province in Central Iran  

PubMed Central

Background: Information on the epidemiology of venomous snake species responsible for envenomation to humans in Iran has not been well documented. In the Kashan city, venomous snakebite remains a recurring medical problem. Information providing the correct identification of snake species responsible for envenomation in this geographic region would be useful to regional medical clinics and personnel for the effective and optimal management of the patients. Materials and Methods: In this cross-sectional study, all patient data was collected from Kashan city and its suburbs. The specific data relating to the taxonomic identification of snakes responsible for envenomation were evaluated. A general approach to the diagnosis and management of patients was also provided. Snakes responsible for bites were transported to a laboratory, where their taxonomic classification was confirmed based on key anatomical features and morphological characteristics. Results: A total of 46 snakes were examined. Of these, 37 (80%) were non-venomous species, and 9 (20%) were identified as venomous. Seven of the nine venomous snake species (78%) were of the family Viperidae, and two specimens (22%) were in the family Colubridae. Specifically, the viperid species were Macrovipera lebetina obtusa, Pseudocerastes persicus, Pseudocerastes fieldi, and Echis carinatus. The two colubrid species were Malpolon monspessulanus insignitus and Psammophis schkari. Conclusion: Five different species of venomous snakes responsible for envenomation in the Kashan city region were confirmed. The viper, P. fieldi, was reported for the first time in the central part of Iran. PMID:24672563

Dehghani, Rouhullah; Mehrpour, Omid; Shahi, Morteza Panjeh; Jazayeri, Mehrdad; Karrari, Parissa; Keyler, Dan; Zamani, Nasim

2014-01-01

62

Discovery of microscopic evidence for shock metamorphism at the Serpent Mound structure, south-central Ohio: Confirmation of an origin by impact  

USGS Publications Warehouse

The origin of the Serpent Mound structure in south-central Ohio has been disputed for many years. Clearly, more evidence was needed to resolve the confusion concerning the origin of the Serpent Mound feature either by endogenic processes or by hypervelocity impact. A petrographic study of 21 samples taken from a core 903 m long drilled in the central uplift of the structure provides evidence of shock metamorphism in the form of multiple sets of planar deformation features in quartz grains, as well as the presence of clasts of altered impact-melt rock. Crystallographic orientations of the planar deformation features show maxima at the shock-characteristic planes of {101??3} and {101??2} and additional maxima at {101??1}, {213??1}, and {516??1}. Geochemical analyses of impact breccias show minor enrichments in the abundances of the siderophile elements Cr, Co, Ni, and Ir, indicating the presence of a minor meteoritic component.

Carlton, R.W.; Koeberl, C.; Baranoski, M.T.; SchuMacHer, G.A.

1998-01-01

63

Anesthesia with Isoflurane and Sevoflurane in the Crested Serpent Eagle (Spilornis cheela hoya): Minimum Anesthetic Concentration, Physiological Effects, Hematocrit, Plasma Chemistry and Behavioral Effects  

PubMed Central

ABSTRACT The initial goal of this study was to determine the minimum anesthetic concentration (MAC) for isoflurane (ISO) and sevoflurane (SEVO) for the crested serpent eagle. Next, we compared the anesthetic effects of each on the physiological effects, hematocrit, plasma chemistry values and behavior in spontaneously breathing captive adult crested serpent eagles. Sixteen eagles were randomly allocated to two groups for anesthesia with ISO (n=8) or SEVO (n=8). First, we measured the MAC values of ISO and SEVO, and four weeks later, we investigated the effect of each on the physiological effects, hematocrit (HCT) and plasma chemistry values. The MAC values of ISO and SEVO for crested serpent eagles were 1.46 ± 0.30 and 2.03 ± 0.32%, respectively. The results revealed no significant differences between the two anesthetics in induction time, while time of extubation to recovery was significantly shorter with SEVO. A time-related increase in end-tidal CO2 and decreases in body temperature and respiratory rates were observed during anesthesia with each anesthetic. There were no significant differences between the effect of the two anesthetics on heart rate, hematocrit, plasma chemistry values or respiration, although each caused minor respiration depression. We concluded that SEVO is a more effective inhalant agent than ISO for use in eagles, showing the most rapidest induction and recovery from anesthesia. PMID:23955396

CHAN, Fang-Tse; CHANG, Geng-Ruei; WANG, Hsien-Chi; HSU, Tien-Huan

2013-01-01

64

A new species of Caryospora Léger, 1904 (Apicomplexa: Eimeriidae) from the endangered Round Island boa Casarea dussumieri (Schlegel) (Serpentes: Bolyeridae) of Round Island, Mauritius: an endangered parasite?  

Microsoft Academic Search

A new species of Caryospora Léger, 1904 (Apicomplexa: Eimeriidae), C. durelli n. sp., is described from the endangered Round Island boa Casarea dussumieri (Schlegel) (Serpentes: Bolyeridae) from Round Island, Mauritius. Six of 11 hosts were infected. Oöcysts are spherical to\\u000a subspherical, 19.2 × 18.2 (17.5–21 × 16–21) ?m, n = 20, and have a shape index (mean length\\/mean width) of 1.05 (1.02–1.09).\\u000a The bi-layered wall is

Peter DaszakStanley; Stanley J. Ball; Daniel G. Streicker; Carl G. Jones; Keith R. Snow

2011-01-01

65

The Descent of the Serpent: Using a Successful Ancient Solar Observatories Webcast from Chichen Itza to Highlight Space Weather Research  

NASA Astrophysics Data System (ADS)

Over the past seven years, NASA's Sun-Earth Connection Education Forum has sponsored and coordinated education and public outreach events to highlight NASA's heliophysics research and discoveries. Our strategy involves using celestial events, such as total solar eclipses and the Transit of Venus, as well as Sun-Earth Day during the March Equinox, to engage K-12 schools and the general public in space science activities, demonstrations, and interactions with space scientists. In collaboration with partners that include the Exploratorium and other museums, Ideum, NASA TV, NASA heliophysics missions, and others, we produce webcasts, other multi-media, and print resources for use by school and informal educators nation-wide and internationally. We provide training and professional development to K-12 educators, museum personnel, amateur astronomers, Girl Scout leaders, etc., so they can implement their own outreach programs taking advantage of our resources. A coordinated approach promotes multiple programs occurring each year under a common theme. As part of an Ancient Observatories theme in 2005, we have successfully featured solar alignments with ancient structures made by indigenous cultures that mark the equinoxes and/or solstices in cultural and historical parks in the Americas. In partnership with the Exploratorium, we produced broadcast-quality and webcast programming during the March equinox that shared heliophysics within a broad cultural context with formal and informal education audiences internationally. The program: "Descent of the Serpent" featured the light and shadow effect at sunset that takes place during the spring equinox at the Pyramid of El Castillo, in Chichén Itzá (México). This program made unique and authentic cultural connections to the knowledge of solar astronomy of the Maya, the living Mayan culture of today, and the importance of the Sun across the ages. We involved Sun-Earth Connection scientists, their missions, and research programs from México and the US to share NASA solar research with diverse audiences in the US and across the world, and to share how our dynamic Sun impacts the Earth and other planets in the solar system. During our presentation, we will highlight the strategies we used to successfully engage Hispanics of native heritage in heliophysics from all over the world.

Hawkins, I.; Higdon, R.; Cline, T.

2006-12-01

66

Reptiles of Tennessee William Sutton, Ph.D.  

E-print Network

, snakes, tuatara, and birds) · Therapsids (current-day mammals) · Anapsids (Turtles and tortoises) General - Scincidae - Teiidae · Squamata (Serpentes [snakes]) - Colubridae - Viperidae · Testudines - Emydidae bite 6. Oviparous Five-lined Skink (Plestiodon fasciatus) Family - Scincidae 1. Bright red head

Gray, Matthew

67

Order Lepidosauria Suborder Serpentes  

E-print Network

approximately 125 mya #12;2 Unique characteristics: Limbless (or nearly so ­ if present, they look like spurs pleurodont teeth, some with specialized adaptations (fangs) Numerous vertebrae, shorter and wider than other distributed. 6 genera, 215 sp. Found in tropics, -lay eggs which may be retained in several species until

Dever, Jennifer A.

68

Order Lepidosauria Suborder Serpentes  

E-print Network

characteristics: l Limbless (or nearly so ­ if present, they look like spurs on each side of the cloaca) l pleurodont teeth, some with specialized adaptations (fangs) l Numerous vertebrae, shorter and wider than in tropics, -lay eggs which may be retained in several species until the embryos are well developed. 2 sp

Dever, Jennifer A.

69

A new species of Caryospora Léger, 1904 (Apicomplexa: Eimeriidae) from the endangered Round Island boa Casarea dussumieri (Schlegel) (Serpentes: Bolyeridae) of Round Island, Mauritius: an endangered parasite?  

PubMed

A new species of Caryospora Léger, 1904 (Apicomplexa: Eimeriidae), C. durelli n. sp., is described from the endangered Round Island boa Casarea dussumieri (Schlegel) (Serpentes: Bolyeridae) from Round Island, Mauritius. Six of 11 hosts were infected. Oöcysts are spherical to subspherical, 19.2 × 18.2 (17.5-21 × 16-21) ?m, n = 20, and have a shape index (mean length/mean width) of 1.05 (1.02-1.09). The bi-layered wall is composed of an outer layer of c.0.6 ?m thick and an inner layer of c.0.4 ?m thick. A micropyle, oöcyst residuum and polar granule are absent. Sporocysts are ellipsoidal, 14.7 × 11.0 (13-16 × 9.5-11.5) ?m, n = 20, and have a shape index of 1.33. Both Stieda and substieda bodies are present. The sporocyst residuum measures c.12 × 4.5 ?m, is surrounded by sporozoites and composed of numerous granules. Refractile bodies are present but not clearly visible. This is the first coccidian parasite reported from the family Bolyeridae and the first species of Caryospora durrelli [corrected] reported from the Mascarenes. Conservation issues concerning parasites of endangered host species are discussed. PMID:21279561

Daszak, Peter; Ball, Stanley J; Streicker, Daniel G; Jones, Carl G; Snow, Keith R

2011-02-01

70

Re-Os Isotope Systematics in Carbonates from Serpent Mound, Ohio: Implications for Re-Os Dating of Crustal Rocks and Ordovician Seawater Os Isotopic Composition  

NASA Astrophysics Data System (ADS)

Eleven core samples of Ordovician carbonate rocks from within and nearby the Serpent Mound (Ohio) cryptoexplosion structure were analyzed for Re-Os isotopes to evaluate the potential role of a meteorite impact in the formation of the structure. The samples span a large range in measured 187Os/188Os from 0.714 to 6.083, and exhibit a strong linear correlation of 187Os/188Os vs. 187Re/188Os. The linear relationship is inconsistent with that expected for a meteorite-crust mixing trend, and is instead interpreted to have age significance. Although the data scatter slightly outside of analytical error, the linear trend can be interpreted as an errorchron with an age of 485 +/- 33 Ma. This age is consistent with previous estimates for these rocks based on paleostratigraphy, and indicates that the Re-Os isotope system is a potentially useful tool for dating crustal rocks that can be difficult to date by other methods. The initial 187Os/188Os indicated by the y-intercept on the Re-Os isochron diagram is 0.54 +/- 0.15, which may reflect the isotopic composition of seawater at the time of deposition. In this case, early Ordovician seawater was distinctly less radiogenic than seawater today, despite having similar Sr isotope signatures. The lower 187Os/188Os but similar 87Sr/86Sr in early Ordovician relative to present-day seawater might reflect the more rapid response of Os compared to Sr isotopes to a decreased continental input to seawater, as expected based on the relative residence times of Os and Sr in seawater (103-105 and 106 Ma, respectively; Levasseur et al., 1999; Oxburgh, 2001). Reduction in uplift and continental weathering rates due to waning Pan African orogenies, as has been proposed to explain a slow decrease in seawater 87Sr/86Sr that started during the early Ordovician (Qing et al., 1998), may explain the relatively unradiogenic Os in seawater at this time.

Widom, E.; Gaddis, S. J.

2002-12-01

71

Body Size Evolution in Insular Speckled Rattlesnakes (Viperidae: Crotalus mitchellii)  

PubMed Central

Background Speckled rattlesnakes (Crotalus mitchellii) inhabit multiple islands off the coast of Baja California, Mexico. Two of the 14 known insular populations have been recognized as subspecies based primarily on body size divergence from putative mainland ancestral populations; however, a survey of body size variation from other islands occupied by these snakes has not been previously reported. We examined body size variation between island and mainland speckled rattlesnakes, and the relationship between body size and various island physical variables among 12 island populations. We also examined relative head size among giant, dwarfed, and mainland speckled rattlesnakes to determine whether allometric differences conformed to predictions of gape size (and indirectly body size) evolving in response to shifts in prey size. Methodology/Principal Findings Insular speckled rattlesnakes show considerable variation in body size when compared to mainland source subspecies. In addition to previously known instances of gigantism on Ángel de la Guarda and dwarfism on El Muerto, various degrees of body size decrease have occurred frequently in this taxon, with dwarfed rattlesnakes occurring mostly on small, recently isolated, land-bridge islands. Regression models using the Akaike information criterion (AIC) showed that mean SVL of insular populations was most strongly correlated with island area, suggesting the influence of selection for different body size optima for islands of different size. Allometric differences in head size of giant and dwarf rattlesnakes revealed patterns consistent with shifts to larger and smaller prey, respectively. Conclusions/Significance Our data provide the first example of a clear relationship between body size and island area in a squamate reptile species; among vertebrates this pattern has been previously documented in few insular mammals. This finding suggests that selection for body size is influenced by changes in community dynamics that are related to graded differences in area over what are otherwise similar bioclimatic conditions. We hypothesize that in this system shifts to larger prey, episodic saturation and depression of primary prey density, and predator release may have led to insular gigantism, and that shifts to smaller prey and increased reproductive efficiency in the presence of intense intraspecific competition may have led to insular dwarfism. PMID:20209105

Meik, Jesse M.; Lawing, A. Michelle; Pires-daSilva, André

2010-01-01

72

Molecular cloning and expression of a functional snake venom vascular endothelium growth factor (VEGF) from the Bothrops insularis pit viper. A new member of the VEGF family of proteins.  

PubMed

During the generation of abundant expressed sequence tags from the Viperidae snake Bothrops insularis venom glands, we identified for the first time a cDNA coding for a putative vascular endothelial growth factor-like (VEGF-like) protein. The deduced primary sequence, after complete sequencing of the longest snake venom VEGF (svVEGF) cDNA, displayed similarity with vertebrate VEGFs and with the hypotensive factor from Vipera aspis venom. Its cDNA was subcloned, expressed in Escherichia coli with a His(6) tag as an insoluble monomer, and purified by Ni(2+)-affinity chromatography after 8 m urea extraction. Antiserum against svVEGF was generated and tested in Western blot against proteins from snake venoms and cellular extracts. The mature svVEGF appears to be ubiquitously distributed throughout snake venoms and was also confirmed by Northern blot studies of other related Viperidae species and by cDNA cloning of svVEGF from Bothrops jararaca pit viper. The produced recombinant protein dimerizes after refolding processes and was biologically characterized, showing ability to increase vascular permeability. These results established that svVEGF is a novel and important active toxin during the early stages of bothropic snake bite envenoming and represents a new member of the VEGF family of proteins. PMID:11517227

Junqueira de Azevedo, I L; Farsky, S H; Oliveira, M L; Ho, P L

2001-10-26

73

Phylogeography of the false smooth snakes, Macroprotodon (Serpentes, Colubridae): mitochondrial  

E-print Network

conditions. The group also spread eastwards into coastal areas of Libya quite recently and on to Egypt are probably relicts from quite recent periods of climatic amelioration in the North African desert. Ã? 2004 towards western Eurasia. The eastern end of the Mediterranean closed in the mid-Miocene period 15

Carranza, Salvador

74

On the identity of Chironius flavolineatus (Serpentes: Colubridae).  

PubMed

The snake genus Chironius Fitzinger, 1826 is endemic to the Neotropical region, occurring from Honduras to Uruguay and northeastern Argentina. Some species of the genus have taxonomic and/or nomenclatural problems, such as C. flavolineatus which lacks agreement in the literature about its authorship and type locality. Some researchers have been suggesting Jan (1863) as the author of the species since he first described C. flavolineatus based on two specimens. However, other researchers report that Jan's description is so incomplete that it is not possible to ascertain what snake he had in mind and therefore suggest Boettger (1885) as the author, since he was the first to provide a detailed description of the species. In the present study one of the syntypes of C. flavolineatus, supposedly destroyed in Second World War, was found. Thus, the taxonomic identity of C. flavolineatus was redefined, its lectotype was designated and the authorship of the taxa is attributed to Jan (1863). PMID:24870316

Hamdan, Breno; Scali, Stefano; Fernandes, Daniel Silva

2014-01-01

75

Geographic variation in Elaphe guttata (Linnaeus) (Serpentes: Colubridae  

E-print Network

~ . . . . . . . . . . ~ ~ Anal Sacs . o o o . ~ o . ~ o . . a ~ Maxillary Teeth Coloration . ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ Dorsal Color Ventral Color ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 50 56 Pattern ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ Cephalic Spear-point . Nuchal Blotch-Spear... col- oration and quantitati. ve and qualitative analysis of pattern than on scale conditions. Special attention has been paid to several pattern conditions that are con- sistantly referred to in the literature for this group. The "spear...

Thomas, Robert Allen

1974-01-01

76

Serpentized mantle at rifted margins: The Goban Spur example  

NASA Astrophysics Data System (ADS)

The crustal structure of rifted continental margins can tell us about the processes that operated from continental extension to eventual break-up and sea floor spreading. Variations between margins may record different processes operating during extension or indicate changes in the external geological controls such as mantle plume influence. Extension between Europe and North America began in the mid Cretaceous, dated at the Goban Spur-Flemish Cap rift as late Hauterivian-early Barremian (126-128 Ma) from deep sea drilling (DSDP leg 80) results on the Goban Spur margin. Marine magnetic anomaly 34 can be identified clearly on both margins and indicates that sea floor spreading began no later than 83 Ma. Syn-rift volcanism is limited to a 20 km basaltic body, with considerable lateral extent, at the foot of the continental slope, emplaced at the end of continental rifting. \

Bullock, A. D.; Minshull, T. A.

2002-12-01

77

The evolution of sperm ultrastructure among Boidae (Serpentes)  

Microsoft Academic Search

We investigate the evolution of sperm ultrastructure of three species of Boidae (Epicrates cenchria, Boa constrictor amarali, and Corallus hortulanus). Spermatozoa of these species are filiform consisting of a head region, containing the nucleus and acrosome complex, a midpiece,\\u000a and a tail region subdivided into principal piece and endpiece. Multilaminar membranes and extracellular microtubules were\\u000a observed next to the plasma

L. Tavares-Bastos; G. R. Colli; S. N. Báo

2008-01-01

78

Purification, sequencing and structural analysis of two acidic phospholipases A2 from the venom of Bothrops insularis (jararaca ilhoa).  

PubMed

Bothrops snake venoms contain a variety of phospholipases (PLA(2)), some of which are myotoxic. In this work, we used reverse-phase HPLC and mass spectrometry to purify and sequence two PLA(2) from the venom of Bothrops insularis. The two enzymes, designated here as BinTX-I and BinTx-II, were acidic (pI 5.05 and 4.49) Asp49 PLA(2), with molecular masses of 13,975 and 13,788, respectively. The amino acid sequence and molecular mass of BinTX-I were identical to those of a PLA(2) previously isolated from this venom (PA2_BOTIN, SwissProt accession number ) while those of BinTX-II indicated that this was a new enzyme. Multiple sequence alignments with other Bothrops PLA(2) showed that the amino acids His48, Asp49, Tyr52 and Asp99, which are important for enzymatic activity, were fully conserved, as were the 14 cysteine residues involved in disulfide bond formation, in addition to various other residues. A phylogenetic analysis showed that BinTX-I and BinTX-II grouped with other acidic Asp49 PLA(2) from Bothrops venoms, and computer modeling indicated that these enzymes had the characteristic structure of bothropic PLA(2) that consisted of three alpha-helices, a beta-wing, a short helix and a calcium-binding loop. BinTX-I (30 microg/paw) produced mouse hind paw edema that was maximal after 1h compared to after 3h with venom (10 and 100 microg/paw); in both cases, the edema decreased after 6h. BinTX-1 and venom (40 microg/ml each) produced time-dependent neuromuscular blockade in chick biventer cervicis preparations that reached 40% and 95%, respectively, after 120 min. BinTX-I also produced muscle fiber damage and an elevation in CK, as also seen with venom. These results indicate that BinTX-I contributes to the neuromuscular activity and tissue damage caused by B. insularis venom in vitro and in vivo. PMID:17140721

Cogo, José C; Lilla, Sergio; Souza, Gustavo H M F; Hyslop, Stephen; de Nucci, Gilberto

2006-12-01

79

Unusual horizontal transfer of a long interspersed nuclear element between distant vertebrate classes  

PubMed Central

We have shown previously by Southern blot analysis that Bov-B long interspersed nuclear elements (LINEs) are present in different Viperidae snake species. To address the question as to whether Bov-B LINEs really have been transmitted horizontally between vertebrate classes, the analysis has been extended to a larger number of vertebrate, invertebrate, and plant species. In this paper, the evolutionary origin of Bov-B LINEs is shown unequivocally to be in Squamata. The previously proposed horizontal transfer of Bov-B LINEs in vertebrates has been confirmed by their discontinuous phylogenetic distribution in Squamata (Serpentes and two lizard infra-orders) as well as in Ruminantia, by the high level of nucleotide identity, and by their phylogenetic relationships. The horizontal transfer of Bov-B LINEs from Squamata to the ancestor of Ruminantia is evident from the genetic distances and discontinuous phylogenetic distribution. The ancestor of Colubroidea snakes is a possible donor of Bov-B LINEs to Ruminantia. The timing of horizontal transfer has been estimated from the distribution of Bov-B LINEs in Ruminantia and the fossil data of Ruminantia to be 40–50 My ago. The phylogenetic relationships of Bov-B LINEs from the various Squamata species agrees with that of the species phylogeny, suggesting that Bov-B LINEs have been maintained stably by vertical transmission since the origin of Squamata in the Mesozoic era. PMID:9724768

Kordis, Dusan; Gubensek, Franc

1998-01-01

80

Horizontal transfer of non-LTR retrotransposons in vertebrates.  

PubMed

Since their discovery in family Bovidae (bovids), Bov-B LINEs, believed to be order-specific SINEs, have been found in all ruminants and recently also in Viperidae snakes. The distribution and the evolutionary relationships of Bov-B LINEs provide an indication of their origin and evolutionary dynamics in different species. The evolutionary origin of Bov-B LINE elements has been shown unequivocally to be in Squamata (squamates). The horizontal transfer of Bov-B LINE elements in vertebrates has been confirmed by their discontinuous phylogenetic distribution in Squamata (Serpentes and two lizard infra-orders) as well as in Ruminantia, by the high level of nucleotide identity, and by their phylogenetic relationships. The direction of horizontal transfer from Squamata to the ancestor of Ruminantia is evident from the genetic distances and discontinuous phylogenetic distribution of Bov-B LINE elements. The ancestral snake lineage (Boidae) has been recognized as a possible donor of Bov-B LINE elements to Ruminantia. The timing of horizontal transfer has been estimated from the distribution of Bov-B LINE elements in Ruminantia and the fossil data of Ruminantia to be 40-50 mya. The phylogenetic relationships of Bov-B LINE elements from the various Squamata species agrees with that of the species phylogeny, suggesting that Bov-B LINE elements have been stably maintained by vertical transmission since the origin of Squamata in the Mesozoic era. PMID:10952205

Kordis, D; Gubensek, F

1999-01-01

81

Molecular evolution of Bov-B LINEs in vertebrates.  

PubMed

Since their discovery in family Bovidae (bovids), Bov-B LINEs, believed to be order-specific SINEs, have been found in all ruminants and recently also in Viperidae snakes. The distribution and the evolutionary relationships of Bov-B LINEs provide an indication of their origin and evolutionary dynamics in different species. The evolutionary origin of Bov-B LINE elements has been shown unequivocally to be in Squamata (squamates). The horizontal transfer of Bov-B LINE elements in vertebrates has been confirmed by their discontinuous phylogenetic distribution in Squamata (Serpentes and two lizard infra-orders) as well as in Ruminantia, by the high level of nucleotide identity, and by their phylogenetic relationships. The direction of horizontal transfer from Squamata to the ancestor of Ruminantia is evident from the genetic distances and discontinuous phylogenetic distribution of Bov-B LINE elements. The ancestor of Colubroidea snakes has been recognized as a possible donor of Bov-B LINE elements to Ruminantia. The timing of horizontal transfer has been estimated from the distribution of Bov-B LINE elements in Ruminantia and the fossil data of Ruminantia to be 40-50 My ago. The phylogenetic relationships of Bov-B LINE elements from the various Squamata species agrees with that of the species phylogeny, suggesting that Bov-B LINE elements have been stably maintained by vertical transmission since the origin of Squamata in the Mesozoic era. PMID:10570995

Kordis, D; Gubensek, F

1999-09-30

82

Unusual horizontal transfer of a long interspersed nuclear element between distant vertebrate classes.  

PubMed

We have shown previously by Southern blot analysis that Bov-B long interspersed nuclear elements (LINEs) are present in different Viperidae snake species. To address the question as to whether Bov-B LINEs really have been transmitted horizontally between vertebrate classes, the analysis has been extended to a larger number of vertebrate, invertebrate, and plant species. In this paper, the evolutionary origin of Bov-B LINEs is shown unequivocally to be in Squamata. The previously proposed horizontal transfer of Bov-B LINEs in vertebrates has been confirmed by their discontinuous phylogenetic distribution in Squamata (Serpentes and two lizard infra-orders) as well as in Ruminantia, by the high level of nucleotide identity, and by their phylogenetic relationships. The horizontal transfer of Bov-B LINEs from Squamata to the ancestor of Ruminantia is evident from the genetic distances and discontinuous phylogenetic distribution. The ancestor of Colubroidea snakes is a possible donor of Bov-B LINEs to Ruminantia. The timing of horizontal transfer has been estimated from the distribution of Bov-B LINEs in Ruminantia and the fossil data of Ruminantia to be 40-50 My ago. The phylogenetic relationships of Bov-B LINEs from the various Squamata species agrees with that of the species phylogeny, suggesting that Bov-B LINEs have been maintained stably by vertical transmission since the origin of Squamata in the Mesozoic era. PMID:9724768

Kordis, D; Gubensek, F

1998-09-01

83

Sexual activity and plasma levels of sex steroids in the aspic viper Vipera aspis L. (Reptilia, Viperidae).  

PubMed

Reproductive behavior and associated sexual activity was studied in individual male and female Vipera aspis over a 3-year period in western France in an attempt to correlate mating behavior with blood levels of gonadal sex steroids. Males had higher average levels of both testosterone (T) and 5 alpha-dihydrotestosterone (DHT) than females. Levels of progesterone (P) did not differ significantly between the two sexes but estradiol-17 beta (E2) concentrations were significantly higher in females during the season of mating. Spring mating behavior and copulation in males was associated with significantly increased levels of T and DHT, compared with postmating males; and a similar, but not significant trend, was evident with autumnal mating. The only statistically significant hormonal difference detected in males showing no sexual activity in autumn, was an elevated level of E2 at 0.52 +/- 0.20 ng/ml compared with 0.09 +/- 0.03 ng/ml in spring-breeding males (P = 0.05). Estrus in females is associated with increased levels of all four steroids but significant only for E2 and DHT. Levels of P were significantly reduced in females displaying seasonal anestrous in the spring immediately following reproduction. Females not displaying estrus in either spring or autumn had significantly lower plasma DHT and E2. Although mating behavior in males is associated statistically with elevated levels of T and DHT, a tight correlation is not obvious at the individual level, suggesting that increased concentrations of androgens are a necessary, but not sufficient, condition for mating. The data from V. aspis suggest that, as in a number of other reptilian species, high circulating levels of androgens function to "condition" or "organize" sexual behavior in males which may be displayed at some later time, well after actual levels have fallen, thus engendering the impression that reproductive behavior may be temporally dissociated from essential hormonal stimuli. PMID:8224772

Saint Girons, H; Bradshaw, S D; Bradshaw, F J

1993-09-01

84

Structural changes of the periosteocytic area in Vipera aspis (L.) (Ophidia, Viperidae) bone tissue in various physiological conditions.  

PubMed

Microradiographs of ribs and vertebrae of the snake Vipera aspis, over an annual cycle, show a significant enlargement of the osteocytic lacunae in the winter months and, for the breeding females, during the period of embryo development. This enlargement is due to resorption of bone substance (periosteocytic osteolysis). The objection that such morphological findings could as well be explained by the formation of new, larger osteocytes derived from recent osteoblasts does not apply to the present animal model. No internal bone remodelling occurs during the annual seasonal cycle and therefore no new osteoblasts would have differentiated to osteocytes in the interior of the bone. In the vertebrae, an additional process is indicated as an area of decreased mineral density, termed demineralization halo, around the periosteocytic lacunae. An electron microscopy study suggests that this process of demineralization is not the first stage of periosteocytic resorption, but an additional process of demineralization. Thus, both osteolysis and demineralization halos in the perilacunar osteocytic region of the bone tissue represent reversible biological processes mediated by the osteocytes. PMID:1893296

Alcobendas, M; Baud, C A; Castanet, J

1991-07-01

85

The influence of body condition on 17-beta estradiol levels in relation to vitellogenesis in female Vipera aspis (Reptilia, Viperidae).  

PubMed

Seventy-six wild Vipera aspis females were caught over 3 years and placed in outdoor enclosures; 39 reproduced and 37 did not. Almost all the reproductive females had a body condition index (BCI) greater than 0.70 when vitellogenesis began. Monthly blood samples were taken by cardiac puncture. The main plasma parameters of vitellogenesis were measured by spectrophotometry: total plasma calcium, phosphorus, phospholipids, cholesterol, triglycerides, proteins, and albumin. Plasma 17-beta estradiol levels were determined by RIA. Vitellogenesis started soon after hibernation in reproductive females with very high 17-beta estradiol concentrations (average of 4.00 ng/ml) and there was a marked mobilization of maternal reserves (fat bodies, liver, and vertebral bone) associated with very high values of plasma calcium, phosphorus, phospholipids, cholesterol, triglycerides, and proteins. The kinetics of the main plasma components were described throughout the vitellogenesis period (from March to early June), when all plasma parameters differed markedly between reproductive and nonreproductive females. After ovulation, the differences between the two groups of females disappeared except in the case of albumin, which remained at a very low level in reproductive females for 6 months. All nonreproductive females had low 17-beta estradiol plasma levels during vitellogenesis (average of 0.08 ng/ml) and there was no suggestion of mobilization of maternal reserves. After vitellogenesis plasma concentrations of estradiol were low in reproductive (an average of 0.08 ng/ml) and in nonreproductive animals (0.06 ng/ml). Five nonreproductive females kept in the laboratory were estrogenized by 17-beta estradiol silastic implants. The 17-beta estradiol concentrations were close to those measured in reproductive females during vitellogenesis. Maternal reserves were mobilized, with almost all metabolic parameters exhibiting the vitellogenic pattern. When the silastic implants were removed, 17-beta estradiol concentrations dropped sharply to a basal level, but the other components were maintained near the vitellogenic values for several months. In contrast to previous studies on viviparous snakes, these results suggest that in V. aspis 17-beta estradiol levels are linked strictly to vitellogenesis. PMID:8194742

Bonnet, X; Naulleau, G; Mauget, R

1994-03-01

86

Changes in plasma progesterone in female Vipera aspis L. (Reptilia, Viperidae) during the sexual cycle in pregnant and nonpregnant females.  

PubMed

The plasma progesterone concentration in female Vipera aspis changes during pregnancy and exhibits an increase before ovulation, a summer peak, a decrease up to parturition, and a new increase at the beginning of hibernation. For females in their first or second year after gestation, the evolution of plasma progesterone shows a spring peak and a summer peak. Whatever the stage of the sexual cycle, females present two annual periods of steroidogenic activity producing plasma progesterone: one in spring and one in summer. All data suggest an annual endogenous endocrinological cycle of reproduction, modulated by external factors (temperature, food availability). The origin of plasma progesterone and its control in the sexual cycle are discussed. PMID:2347489

Naulleau, G; Fleury, F

1990-06-01

87

Edema induced by Bothrops asper (Squamata: Viperidae) snake venom and its inhibition by Costa Rican plant extracts.  

PubMed

We tested the capacity of leaf (Urera baccifera, Loasa speciosa, Urtica leptuphylla, Chaptalia nutans, and Satureja viminea) and root (Uncaria tomentosa) extracts to inhibit edema induced by Bothrops asper snake venom. Edema-forming activity was studied plethysmographically in the rat hind paw model. Groups of rats were injected intraperitoneally with various doses of each extract and, one hour later, venom was injected subcutaneously in the right hind paw. Edema was assessed at various time intervals. The edematogenic activity was inhibited in those animals that received an injection U. tomentosa, C. nutans or L. speciosa extract. The extract of U. baccifera showed a slight inhibition of the venom effect. Extract from S. viminea and, to a lesser extent that of U. leptuphylla, induced a pro-inflammatory effect, increasing the edema at doses of 250 mg/kg at one and two hours. PMID:18494294

Badilla, Beatriz; Chaves, Fernando; Mora, Gerardo; Poveda, Luis J

2006-06-01

88

A relict lineage and new species of green palm-pitviper (Squamata, Viperidae, Bothriechis) from the Chortís Highlands of Mesoamerica  

PubMed Central

Abstract A new species of palm-pitviper of the genus Bothriechis is described from Refugio de Vida Silvestre Texíguat in northern Honduras. The new species differs from congeners by having 19 dorsal scale rows at midbody, a bright green dorsal coloration in adults, the prelacunal scale fused to the second supralabial, and in representing a northern lineage that is sister to Bothriechis lateralis, which is distributed in Costa Rica and western Panama and is isolated from the new taxon by the Nicaraguan Depression. This represents the 15th endemic species occurring in Refugio de Vida Silvestre Texíguat, one of the richest herpetofaunal sites in Honduras, itself being the country with the highest degree of herpetofaunal endemism in Central America. We name this new species in honor of a Honduran conservationist slain in fighting against illegal logging, highlighting the sacrifices of rural activists in battling these issues and the critical importance of conservation in these areas. PMID:23794885

Townsend, Josiah H.; Medina-Flores, Melissa; Wilson, Larry David; Jadin, Robert C.; Austin, James D.

2013-01-01

89

Modeling nucleotide evolution at the mesoscale: the phylogeny of the neotropical pitvipers of the Porthidium group (viperidae: crotalinae).  

PubMed

We analyzed the phylogeny of the Neotropical pitvipers within the Porthidium group (including intra-specific through inter-generic relationships) using 1.4 kb of DNA sequences from two mitochondrial protein-coding genes (ND4 and cyt-b). We investigated how Bayesian Markov chain Monte-Carlo (MCMC) phylogenetic hypotheses based on this 'mesoscale' dataset were affected by analysis under various complex models of nucleotide evolution that partition models across the dataset. We develop an approach, employing three statistics (Akaike weights, Bayes factors, and relative Bayes factors), for examining the performance of complex models in order to identify the best-fit model for data analysis. Our results suggest that: (1) model choice may have important practical effects on phylogenetic conclusions even for mesoscale datasets, (2) the use of a complex partitioned model did not produce widespread increases or decreases in nodal posterior probability support, and (3) most differences in resolution resulting from model choice were concentrated at deeper nodes. Our phylogenetic estimates of relationships among members of the Porthidium group (genera: Atropoides, Cerrophidion, and Porthidium) resolve the monophyly of the three genera. Bayesian MCMC results suggest that Cerrophidion and Porthidium form a clade that is the sister taxon to Atropoides. In addition to resolving the intra-specific relationships among a majority of Porthidium group taxa, our results highlight phylogeographic patterns across Middle and South America and suggest that each of the three genera may harbor undescribed species diversity. PMID:16024260

Castoe, Todd A; Sasa, Mahmood M; Parkinson, Christopher L

2005-12-01

90

Gene expression of inflammatory mediators induced by jararhagin on endothelial cells.  

PubMed

Snake venom metalloproteinases (SVMP) are abundant toxins in venoms of viper snakes and play a relevant role in the complex and multifactorial tissue damage characteristic of Viperidae envenoming. Jararhagin, a SVMP isolated from Bothrops jararaca venom, induces a fast onset hemorrhagic lesions acting directly on the capillary vessels, which are disrupted by toxin adhesion and degradation of extracellular matrix proteins like collagen IV. Jararhagin also triggers inflammatory response, where endothelial cells are activated, resulting in the enhanced rolling of circulating leukocytes, nitric oxide generation, prostacyclin production and pro-inflammatory cytokines release. Jararhagin also decreases endothelial cells viability inducing apoptosis (in vitro studies). In the present study we attempted to correlate the effect of sub-apoptotic doses of jararhagin on human umbilical vein endothelial cells (HUVECs) and gene expression of pro-inflammatory mediators, using microarray assay, real time PCR and detection of specific proteins on HUVEC surface or released in the medium. Jararhagin was effective in activate and up-regulate the gene expression of different mediators such as E-selectin, VCAM-1, IL-8, CD69, Ang-2 and MMP-10. Despite the increase in expression of genes coding for such molecules, jararhagin did not induce increased concentrations of E-selectin, VCAM-1 and IL-8 produced or released by endothelial cells. In conclusion, jararhagin is able to activate pro-inflammatory gene transcription on endothelial cells however this stimulus is not sufficient to result in the consequent expression of pro-inflammatory effectors molecules like E-selectin, VCAM-1 and IL-8. The time courses of these events, as well as the doses of jararhagin are important points to be addressed herein. PMID:22960448

Lopes, Daiana S; Faquim-Mauro, Eliana; Magalhães, Geraldo S; Lima, Iara C; Baldo, Cristiani; Fox, Jay W; Moura-da-Silva, Ana Maria; Clissa, Patricia B

2012-11-01

91

Shedding light on serpent sight: the visual pigments of henophidian snakes.  

PubMed

The biologist Gordon Walls proposed his "transmutation" theory through the 1930s and the 1940s to explain cone-like morphology of rods (and vice versa) in the duplex retinas of modern-day reptiles, with snakes regarded as the epitome of his hypothesis. Despite Walls' interest, the visual system of reptiles, and in particular snakes, has been widely neglected in favor of studies of fishes and mammals. By analyzing the visual pigments of two henophidian snakes, Xenopeltis unicolor and Python regius, we show that both species express two cone opsins, an ultraviolet-sensitive short-wavelength-sensitive 1 (SWS1) (lambda(max) = 361 nm) pigment and a long-wavelength-sensitive (LWS) (lambda(max) = 550 nm) pigment, providing the potential for dichromatic color vision. They also possess rod photoreceptors which express the usual rod opsin (Rh1) pigment with a lambda(max) at 497 nm. This is the first molecular study of the visual pigments expressed in the photoreceptors of any snake species. The presence of a duplex retina and the characterization of LWS, SWS1, and Rh1 visual pigments in henophidian snakes implies that "lower" snakes do not provide support for Walls' transmutation theory, unlike some "higher" (caenophidian) snakes and other reptiles, such as geckos. More data from other snake lineages will be required to test this hypothesis further. PMID:19515920

Davies, Wayne L; Cowing, Jill A; Bowmaker, James K; Carvalho, Livia S; Gower, David J; Hunt, David M

2009-06-10

92

Helminthic parasites of water snakes, Natrix spp. (Serpentes: Colubridae), from southeast Texas  

E-print Network

Digenea Cestoda TABLE OF CONTENTS Page 22 23 23 27 31 34 34 34 57 Order Proteocephalidea Nematoda 57 60 Order Ascarididea Order Dioctophymidea Order Rhabdiasidea Order Sp1ruridea Order Strongylidea Order Trichur1dea Acanthocephala... h d Collins. 1969 N. ~si eden h North Carolina (eastern) North Carolina (eastern) Acanthocephala Order Echinorhynchidea Southwell and Macfie. 1925 Family Echinorhynchidae (Cobbold. 1879) Hamann, 1892 I) Le torh nchoides thecatus (Linton...

Guidry, Edmund Vaughn

1976-01-01

93

A new species of Chironius Fitzinger, 1826 from the state of Bahia, Northeastern Brazil (Serpentes: Colubridae).  

PubMed

We describe a new species of Chironius Fitzinger, 1826 from the highlands of Chapada Diamantina, state of Bahia, Brazil. The new species is distinguished from all currently recognized congeners by a unique combination of states of characters on coloration, scale counts, scale ornamentation, and hemipenis. The new species closely resembles Chironius flavolineatus (Jan, 1863) in color pattern, but differs from the later taxon by the presence of two to four posterior temporal scales; cloacal shield entire; six to ten rows of keeled dorsal scales at midbody; ventral scales with posterior dark edges forming conspicuous transverse bars along almost the entire venter; conspicuous dark longitudinal stripes (in "zigzag") in the midventral portion of subcaudals; region of medial constriction of hemipenis slightly covered with spinules separating calyces of apex from spines below region of constriction; and sulcus spermaticus situated on convex face of hemipenis in lateral view. The new species is apparently restricted to Chapada Diamantina, corroborating the biological importance of this region from a conservational perspective. PMID:25543653

Fernandes, Daniel Silva; Hamdan, Breno

2014-01-01

94

Morphological variation and taxonomy of Atractus latifrons (Günther, 1868) (Serpentes: Dipsadidae).  

PubMed

As currently understood Atractus latifrons is widely distributed in South America, occurring from Suriname to the east of the Andes in Bolivia. Throughout this widespread distribution, at least three distinct color patterns were previously reported in the literature. Here, we test whether quantitative variation and qualitative distribution of morphological characters are correlated with any color pattern displayed by the species along its range. We recognize three aposematic color patterns (bicolor in monads, tricolor in dyads, and tricolor in tetrads) for A. latifrons. We found no obvious correspondence between these patterns and any character systems analyzed herein. Additionally, we redescribe the holotype of A. latifrons and report on morphological variability (meristics, morphometrics, color patterns, and hemipenis) and geographical distribution (extending its distribution to the state Roraima, Brazil) of the species.  PMID:25283190

Almeida, Paula C; Feitosa, Darlan T; Passos, Paulo; Prudente, Ana L C

2014-01-01

95

DISCOVERY OF THE MADAGASCAR SERPENT-EAGLE, EUTRIORCHIS ASTUR, IN CENTRAL AND SOUTHEASTERN MADAGASCAR. (U915543)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

96

Kleptothermy: an additional category of thermoregulation, and a possible example in sea kraits (Laticauda laticaudata, Serpentes).  

PubMed

Lacking the capacity for thermogenesis, most ectotherms inhabiting thermally heterogeneous environments rely instead upon exploiting that ambient heterogeneity. In many cases they maintain body temperatures within a narrow range despite massive spatial and temporal variation in ambient conditions. Reliance on diverse thermal opportunities is reflected in specific terms for organisms that bask in sunlight to regulate their temperature (heliotherms), or that press their bodies against warm substrates to facilitate heat flow (thigmotherms), or that rely on large body mass to maintain thermal constancy (gigantothermy). We propose an additional category of thermoregulators: kleptotherms, which regulate their own temperature by 'stealing' heat from other organisms. This concept involves two major conditions: the thermal heterogeneity created by the presence of a warm organism in a cool environment and the selective use of that heterogeneity by another animal to maintain body temperatures at higher (and more stable) levels than would be possible elsewhere in the local area. Kleptothermy occurs in endotherms also, but is usually reciprocal (rather than unilateral as in ectotherms). Thermal monitoring on a small tropical island documents a possible example of kleptothermy, based on high stable temperatures of a sea snake (Laticauda laticaudata) inside a burrow occupied by seabirds. PMID:19656862

Brischoux, François; Bonnet, Xavier; Shine, Richard

2009-12-23

97

A review of the African members of the genus Micrelaps Boettger 1880 (Serpentes Atractaspididae)  

Microsoft Academic Search

An analysis of all available material, including the types of the various species of African Micrelaps, reveals that M. boettgeri Boulenger 1896 is a junior synonym of M. vaillanti (Mocquard 1888). Micrelaps bicoloratus Sternfeld 1910 from Kenya is different from sympatric M. vaillanti and is considered a valid species. Tanzanian populations of M. bicoloratus differ in colouration from the Kenyan

Jens B. Rasmussen

2002-01-01

98

A phylogenetic analysis of Pseudonaja (Hydrophiinae, Elapidae, Serpentes) based on mitochondrial DNA sequences.  

PubMed

A phylogenetic analysis of mitochondrial ND4 and adjacent tRNA sequences for a geographically extensive series of specimens reveals nine major clades within Pseudonaja, of which six are largely coincident with nominal taxa (P. affinis, P. guttata, P. inframacula, P. ingrami, P. modesta, and P. textilis). The remaining three clades are composed of specimens presently referred to P. nuchalis. Two of these clades correspond with the "Darwin" and "Southern" morphs of previous authors, while the third clade incorporates the "Orange with black head" and "Pale head, grey nape" morphs. We are unable to confirm the presence of consistent karyotypic differences between "Orange with black head" and "Pale head, grey nape" specimens, however, P. inframacula, P. textilis, and P. nuchalis "Darwin" are found to exhibit distinctive karyotypes, as previously reported. These results, in conjunction with additional observations of karyotpic and morphological variation, are consistent with nine historically-independent lineages (i.e., species) within Pseudonaja. There is strong support for a clade composed of P. affinis, P. inframacula, P. ingrami, P. textilis, and the three P. nuchalis lineages, and for the relationships (P. inframacula, P. nuchalis "Southern") and (P. nuchalis "Darwin", P. nuchalis "Orange with black head"--"Pale head, grey nape" ). PMID:16098768

Skinner, Adam; Donnellan, Stephen C; Hutchinson, Mark N; Hutchinson, Rhonda G

2005-11-01

99

Close karyological kinship between the reptilian suborder serpentes and the class aves  

Microsoft Academic Search

In contrast to the situation found in two classes of warm-blooded vertebrates, mammals and birds, the class Reptilia is not uniform with regard to total genetic content; rather, it contains two distinct categories. The close cytological kinship between snakes and birds was revealed. Both are almost identical in total genetic content, which is about 50 per cent that of placental

Willy Beçak; Maria Luiza Beçak; H. R. S. Nazareth; Susumu Ohno

1964-01-01

100

Society for the Study of Amphibians and Reptiles Feeding Envenomation by Arrhyton exiguum (Serpentes: Colubridae)  

E-print Network

of the lizard, Cordyluspolyzonuspolyzonus (Sauria: Cordylidae) in the Orange Free State. S. Afr. J. Zool. 24:263-269. . 1990. Seasonal testicular activity and mor- phometric variation in the femoral glands of the lizard in the female viviparous lizard Cordylus giganteus. Amphibia- Reptilia 12:329-342. VERON, J. E. N. 1969

Leal, Manuel S.

101

Mechanical properties of the integument of the common gartersnake, Thamnophis sirtalis (Serpentes: Colubridae).  

PubMed

The evolution of the ophidian feeding mechanism has involved substantial morphological restructuring associated with the ability to ingest relatively large prey. Previous studies examining the morphological consequences of macrophagy have concentrated on modifications of the skull and cephalic musculature. Although it is evident that macrophagy requires highly compliant skin, the mechanical properties of the ophidian integument have received limited attention, particularly in the context of feeding. We examined mechanical properties of skin along the body axis in Thamnophis sirtalis (Colubridae). Data were collected from tensile tests and were analyzed using a multivariate analysis of variance (MANOVA) and post-hoc multiple comparison tests. Significant differences in mechanical properties were detected among regions of the body. In general, prepyloric skin is more compliant than postpyloric skin, consistent with the demands of macrophagy. PMID:16043596

Rivera, Gabriel; Savitzky, Alan H; Hinkley, Jeffrey A

2005-08-01

102

The transvestite serpent: why do male garter snakes court (some) other males?  

PubMed

In large mating aggregations of red-sided garter snakes, Thamnophis sirtalis parietalis, in Manitoba, male courtship is directed not only to females, but also to other males with female-like skin lipids ('she-males'). We show that 'she-maleness' is an intrinsic property of a male rather than an artefact of lipid transfer from females, and that male-male courtship is very common in the field. She-males were distinctive in terms of appearance (they were heavier than other males and more often covered with mud), behaviour (they were inactive and rarely courted females) and performance (they were slow crawlers, ineffective courters and easily outcompeted by other males in mating trials). 'She-maleness' was not a characteristic of a particular subset of males, as envisaged in previous work; instead, it was a transitory phase that most (perhaps all) male snakes passed through soon after they first emerged from the winter den. Recently emerged males spent their first day or two relatively inactive, while restoring physiological functions (including locomotor performance and courtship ability). Experimental application of female skin lipids on to males dramatically decreased courtship levels of the recipient snakes. Thus, recently emerged males may derive two kinds of benefit from mimicking female skin lipids. First, female mimicry 'switches off' the male's own (energetically expensive) courtship at a time when that courtship would be unproductive. Second, it may disadvantage his rivals by distracting them from females, and increasing their energy expenditure. Copyright 2000 The Association for the Study of Animal Behaviour. PMID:10675257

Shine; Harlow; LeMaster; Moore; Mason

2000-02-01

103

Mechanical properties of the integument of the common gartersnake, Thamnophis sirtalis (Serpentes: Colubridae)  

Microsoft Academic Search

The evolution of the ophidian feeding mechanism has involved substantial morphological restructuring associated with the ability to ingest relatively large prey. Previous studies examining the morphological consequences of macrophagy have concentrated on modifications of the skull and cephalic musculature. Although it is evident that macrophagy requires highly compliant skin, the mechanical properties of the ophidian integument have received limited attention,

Gabriel Rivera; Alan H. Savitzky; Jeffrey A. Hinkley

2005-01-01

104

The Serpent in the Garden State: Juvenile Delinquency in 1920s New Jersey  

ERIC Educational Resources Information Center

School administrators, educators, psychologists, social workers, the juvenile courts, institutional reformers, and others shape the manner in which children are labeled, portrayed, and treated. However, the agendas, motivations, political language, and influence of these "helping professionals" in "treating" and "reforming" juvenile delinquents…

Ferry, Thomas M.

2010-01-01

105

Molecular Systematics of the Western Rattlesnake, Crotalus viridis (Viperidae), with Comments on the Utility of the D-Loop in Phylogenetic Studies of Snakes  

Microsoft Academic Search

Crotalus viridis, the western rattlesnake, ranges throughout western North America and has been divided into at least eight subspecies. However, the validity of and relationships among these subspecies and the monophyly of C. viridis as a whole are questionable. We used mitochondrial DNA sequence data from the D-loop region and ND2 gene to examine the relationships among 26 populations of

Kyle G. Ashton; Alan de Queiroz

2001-01-01

106

Molecular systematics of the western rattlesnake, Crotalus viridis (Viperidae), with comments on the utility of the D-loop in phylogenetic studies of snakes.  

PubMed

Crotalus viridis, the western rattlesnake, ranges throughout western North America and has been divided into at least eight subspecies. However, the validity of and relationships among these subspecies and the monophyly of C. viridis as a whole are questionable. We used mitochondrial DNA sequence data from the D-loop region and ND2 gene to examine the relationships among 26 populations of C. viridis and to test the monophyly of this species. These data were analyzed separately and combined using maximum-likelihood and maximum-parsimony. The C. viridis group was monophyletic in all combined analyses, consisting of two strongly divergent clades. We recommend that these clades be recognized as two distinct evolutionary species: C. viridis and C. oreganus. Crotalus viridis should be restricted to the subspecies viridis and nuntius and the remaining subspecies be assigned to the species C. oreganus. Our data do not allow strong evaluation of the validity of the subspecies. We found that the ND2 gene had greater sequence divergences among closely related individuals than the D-loop region, but this relationship reversed at higher levels of divergence. This pattern is apparently due to: (1) ND2 third positions evolving faster than the D-loop but becoming saturated at higher levels of divergence, and (2) the D-loop evolving faster than ND2 second (and possibly first) positions. Our results suggest that the ND2 gene is preferable for examining intraspecific relationships and the D-loop may better resolve relationships between species of snakes. The latter result is contrary to the common perception of the phylogenetic utility of the D-loop. Another unusual result is that the 145 bp spacer region, adjacent to the 5' end of the light strand of the D-loop, provides greater phylogenetic resolution than the 1030 bp D-loop. PMID:11697914

Ashton, K G; de Queiroz, A

2001-11-01

107

Comparative study of anticoagulant and procoagulant properties of 28 snake venoms from families Elapidae, Viperidae, and purified Russell's viper venom-factor X activator (RVV-X)  

PubMed Central

Snake venoms consist of numerous molecules with diverse biological functions used for capturing prey. Each component of venom has a specific target, and alters the biological function of its target. Once these molecules are identified, characterized, and cloned; they could have medical applications. The activated clotting time (ACT) and clot rate were used for screening procoagulant and anticoagulant properties of 28 snake venoms. Crude venoms from Daboia russellii siamensis, Bothrops asper, Bothrops moojeni, and one Crotalus oreganus helleri from Wrightwood, CA, had procoagulant activity. These venoms induced a significant shortening of the ACT and showed a significant increase in the clot rate when compared to the negative control. Factor X activator activity was also measured in 28 venoms, and D. r. siamensis venom was 5–6 times higher than those of B. asper, B. moojeni, and C. o. helleri from Wrightwood County. Russell's viper venom-factor X activator (RVV-X) was purified from D. r. siamensis venom, and then procoagulant activity was evaluated by the ACT and clot rate. Other venoms, Crotalus atrox and two Naja pallida, had anticoagulant activity. A significant increase in the ACT and a significant decrease in the clot rate were observed after the addition of these venoms; therefore, the venoms were considered to have anticoagulant activity. Venoms from the same species did not always have the same ACT and clot rate profiles, but the profiles were an excellent way to identify procoagulant and anticoagulant activities in snake venoms. PMID:20677373

Suntravat, Montamas; Nuchprayoon, Issarang; Pérez, John C.

2012-01-01

108

Comparative venom gland transcriptome surveys of the saw-scaled vipers (Viperidae: Echis) reveal substantial intra-family gene diversity and novel venom transcripts  

PubMed Central

Background Venom variation occurs at all taxonomical levels and can impact significantly upon the clinical manifestations and efficacy of antivenom therapy following snakebite. Variation in snake venom composition is thought to be subject to strong natural selection as a result of adaptation towards specific diets. Members of the medically important genus Echis exhibit considerable variation in venom composition, which has been demonstrated to co-evolve with evolutionary shifts in diet. We adopt a venom gland transcriptome approach in order to investigate the diversity of toxins in the genus and elucidate the mechanisms which result in prey-specific adaptations of venom composition. Results Venom gland transcriptomes were created for E. pyramidum leakeyi, E. coloratus and E. carinatus sochureki by sequencing ~1000 expressed sequence tags from venom gland cDNA libraries. A standardised methodology allowed a comprehensive intra-genus comparison of the venom gland profiles to be undertaken, including the previously described E. ocellatus transcriptome. Blast annotation revealed the presence of snake venom metalloproteinases, C-type lectins, group II phopholipases A2, serine proteases, L-amino oxidases and growth factors in all transcriptomes throughout the genus. Transcripts encoding disintegrins, cysteine-rich secretory proteins and hyaluronidases were obtained from at least one, but not all, species. A representative group of novel venom transcripts exhibiting similarity to lysosomal acid lipase were identified from the E. coloratus transcriptome, whilst novel metallopeptidases exhibiting similarity to neprilysin and dipeptidyl peptidase III were identified from E. p. leakeyi and E. coloratus respectively. Conclusion The comparison of Echis venom gland transcriptomes revealed substantial intrageneric venom variation in representations and cluster numbers of the most abundant venom toxin families. The expression profiles of established toxin groups exhibit little obvious association with venom-related adaptations to diet described from this genus. We suggest therefore that alterations in isoform diversity or transcript expression levels within the major venom protein families are likely to be responsible for prey specificity, rather than differences in the representation of entire toxin families or the recruitment of novel toxin families, although the recruitment of lysosomal acid lipase as a response to vertebrate feeding cannot be excluded. Evidence of marked intrageneric venom variation within the medically important genus Echis strongly advocates further investigations into the medical significance of venom variation in this genus and its impact upon antivenom therapy. PMID:19948012

2009-01-01

109

'Heaven' for serpents? A mark-recapture study of tiger snakes (Notechis scutatus) on Carnac Island, Western Australia  

Microsoft Academic Search

Animals resident on small islands provide excellent opportunities to carry out detailed mark- recapture studies. Populations are closed and ecosystems are often simpler than those of mainland sites. These factors enable the study of cryptic species that have otherwise been neglected. Snakes are notable for their secretive nature and, as a result, few natural populations have been accurately described through

Xavier Bonnet; David Pearson; Mitchell Ladyman; Olivier Lourdais; Don Bradshaw

2002-01-01

110

Molecular phylogeny of the Australian venomous snake genus Hoplocephalus (Serpentes, Elapidae) and conservation genetics of the threatened H. stephensii  

Microsoft Academic Search

The Australian elapid snakeHoplocephalus stephensii (Stephens' BandedSnake) is patchily distributed in disjunctforest remnants in eastern Australia and islisted as threatened in both states in which itoccurs (Qld and NSW). Here we focus on thephylogeography of H. stephensii toaddress (1) the genetic distinctiveness of thistaxon within its genus and (2) the level ofgenetic diversity present within and betweendisjunct populations from throughout

Scott J. Keogh; Ian A. W. Scott; Mark Fitzgerald; Richard Shine

2003-01-01

111

A NEW SPECIES OF HEPATOZOON (APICOMPLEXA: ADELEORINA) FROM PYTHON REGIUS (SERPENTES: PYTHONIDAE) AND ITS EXPERIMENTAL TRANSMISSION BY A MOSQUITO VECTOR  

Microsoft Academic Search

Hepatozoon ayorgbor n. sp. is described from specimens of Python regius imported from Ghana. Gametocytes were found in the peripheral blood of 43 of 55 snakes examined. Localization of gametocytes was mainly inside the erythrocytes; free gametocytes were found in 15 (34.9%) positive specimens. Infections of laboratory-reared Culex quinquefasciatus feeding on infected snakes, as well as experimental infection of juvenile

Michal Sloboda; Martin Kamler; Jana Bulantová; Jan Votýpka; David Modrý

2007-01-01

112

The Eagle, the Jaguar, and the Serpent. Indian Art of the Americas; North America: Alaska, Canada, the United States.  

ERIC Educational Resources Information Center

The origins of Native Americans are traced through art forms in this history of American art. The basic time periods for this history are determined and defined as the formative horizon, the classic horizon, and the historical horizon. Art forms used throughout these time periods are described in terms of technique and aesthetics. The arts and…

Covarrubias, Miguel

113

Sea snakes in Australian waters (Serpentes: subfamilies Hydrophiinae and Laticaudinae)-a review with an updated identification key.  

PubMed

Sea snakes (Elapidae, subfamilies Hydrophiinae and Laticaudinae) reach high species richness in the South China Sea and in the Australian region; however, most countries in the two regions still lack up-to-date checklists and identification tools for these snakes. We present an updated reviewed checklist and a new complete identification key to sea snakes in Australian waters. The identification key includes 29 species documented and 4 possibly occurring taxa and is based mostly on easy-to-use external characters. We find no evidence for breeding populations of Laticauda in Australian waters, but include the genus on the list of possibly occurring taxa.  PMID:25283923

Rasmussen, Arne Redsted; Sanders, Kate Laura; Guinea, Michael L; Amey, Andrew P

2014-01-01

114

Species Delimitation in the Continental Forms of the Genus Epicrates (Serpentes, Boidae) Integrating Phylogenetics and Environmental Niche Models  

PubMed Central

Until recently, the genus Epicrates (Boidae) presented only one continental species, Epicrates cenchria, distributed in Central and South America, but after a taxonomic revision using morphologic characters five species were recognized: E. cenchria, E. crassus, E. maurus, E. assisi, and E. alvarezi. We analyzed two independent data sets, environmental niche models and phylogeny based on molecular information, to explore species delimitation in the continental species of this genus. Our results indicated that the environmental requirements of the species are different; therefore there are not evidences of ecological interchangeability among them. There is a clear correlation between species distributions and the major biogeographic regions of Central and South America. Their overall distribution reveals that allopatry or parapatry is the general pattern. These evidences suggest that habitat isolation prevents or limits gene exchange among them. The phylogenetic reconstruction showed that the continental Epicrates are monophyletic, being E. alvarezi the sister species for the remaining two clades: E. crassus - E. assisi, and E. maurus - E. cenchria. The clade grouping the continental Epicrates is the sister taxon of the genus Eunectes and not of the Caribbean Epicrates clade, indicating that the genus is paraphyletic. There is a non-consistent pattern in niche evolution among continental Epicrates. On the contrary, a high variation and abrupt shifts in environmental variables are shown when ancestral character states were reconstructed on the sequence-based tree. The degree of genetic and ecological divergence among continental Epicrates and the phylogenetic analyses support the elevation to full species of E. cenchria, E. crassus, E. maurus, E. assisi, and E. alvarezi. PMID:21912634

Rivera, Paula C.; Di Cola, Valeria; Martínez, Juan J.; Gardenal, Cristina N.; Chiaraviglio, Margarita

2011-01-01

115

Society for the Study of Amphibians and Reptiles Effects of Prey Type on the Feeding Behavior of Alsophis portoricensis (Serpentes  

E-print Network

Eleutherodactylus coqui. Subduing time was higher for lizards, but swallowing and handling times were longer cristatellus and Eleutherodactylus coqui. Predators may show variation in their feed- ing behavior when

Leal, Manuel S.

116

A perspective on natural products research and ethnopharmacology in Mexico: the eagle and the serpent on the prickly pear cactus.  

PubMed

Mexico's extraordinarily rich cultural and floristic diversity has fascinated explorers and researchers ever since the "New World" was discovered for and by Europeans. For many decades, natural product research has been a very active field of research in Mexico, and there also are some ongoing ethnopharmacological research efforts. This review provides an overview and critical appraisal on some key developments in these fields and examples of medicinal plants used by indigenous communities that have become of great local importance in Mexican popular medicine. In this review, the focus is on plants with effects on the CNS, diabetes, metabolic syndrome, inflammatory processes, and gastrointestinal disorders. While some of the major food plants consumed worldwide originate from southern North America, only very few medicinal plants have become of major global importance. Opuntia species are now used increasingly to manage diabetes and metabolic syndrome and represent an example of a novel medicinal product/supplement. Undoubtedly, narcotic and mind-altering drugs both have received the widest scientific interest and have attracted considerable popular attention. The history of use of the indigenous Mexican Materia Medica in the context of research on local and popular resources specifically with regard to the diverse challenges in the context of studying the world's biodiversity and the development of comparative and semiquantitative ethnobotanical research methods is discussed herein. Natural product and ethnopharmacological research in Mexico seems to have been influenced by the political and societal developments originating from the Convention on Biological Diversity (CBD) and subsequent conventions, which have not yet had the desired effect of giving value to these local resources, as they might deserve. Their equitable and sustainable implementation remains a challenge. Natural product research and ethnopharmacology will play a key role in developing an adequate evidence base for such products derived from local and traditional knowledge in Mexico. PMID:24559070

Heinrich, Michael; Frei Haller, Barbara; Leonti, Marco

2014-03-28

117

Variation in mating systems and sexual size dimorphism between populations of the Australian python Morelia spilota (Serpentes: Pythonidae)  

Microsoft Academic Search

Although adaptationist hypotheses predict a functional relationship between mating systems and sexual size dimorphism, such predictions are difficult to test because of the high degree of phylogenetic conservatism in both of these traits. Taxa that show intraspecific variation in mating systems hence offer valuable opportunities for more direct tests of evolutionary-ecological hypotheses. Based on a collation of published and unpublished

R. Shine; M. Fitzgerald

1995-01-01

118

Large snakes in a mosaic rural landscape: The ecology of carpet pythons Morelia spilota (serpentes: Pythonidae) in coastal eastern Australia  

Microsoft Academic Search

How can large pythons coexist with human beings in highly modified habitats throughout the eastern coastal region of Australia, when the same species has undergone rapid declines in other parts of the country? To investigate this question, we surgically implanted miniature temperature-sensitive radiotransmitters into 19 adult carpet pythons Morelia spilota (body lengths 1·3–2·8 m; 1·4–7·0 kg) from two study sites

R. Shine; M. Fitzgerald

1996-01-01

119

["Lingue di seripi", "serpents' tongues" and "glossopetrae". Highlights from the history of popular "cult" medicine in early modern times].  

PubMed

In the 16th, 17th and 18th century "Glossopetrae", popularly known as "Lingue di Serpi", found on the Mediterranean island of Malta, were extensively used for medical purposes as antidotes. These fossil teeth, including specimens of the "Carcharodon Megalodon" (an extinct variant of the great white shark), were ground to powder or used as amulet pendants and "credence" and exported to pharmacies and shops in various cities of Europe. In antiquity, authors like Plinius or Solinus, excluding any religious connotations, had regarded "Glossopetrae" as objects "fallen from heaven on dark moonless nights". However, from the beginning of the 16th century the miraculous antidotic power of the specimens found at Malta was very strongly connected with the Pauline cult there. This cult owed ist origin to the excerpt of the shipwreck of the Apostle of the Gentiles on this island, as recorded in the New Testament. As in so many cases found in medieval and early modern medicine and pharmacy, the renown, collection, distribution and use of the antidote "Glossopetrae" or "Lingue di Serpi" was never limited to its real chemical and pharmaceutical properties. In the period of enlightenment and secular thinking mythic medicine as "Glossopetrae" had lost ist "magical" power. Consequently, with beginning of the late 18th century also the Maltese "Glossopetrae" featured in literature merely as exotic objects of curiosity or symbols of an age bound to medical superstition. PMID:9333999

Freller, T

1997-01-01

120

76 FR 61733 - Endangered Species; Receipt of Applications for Permit  

Federal Register 2010, 2011, 2012, 2013, 2014

...parrot), Sturnidae (does not include Aplonis pelzelni), Threskiornithidae, Boidae (does not include Mona or Puerto Rico Boas), Iguanidae, Pelomedusidae, Testudinidae, Varanidae, Viperidae (includes Crotalus unicolor but not Crotalus...

2011-10-05

121

Inhibitory properties of the antibothropic complex from the South American opossum ( Didelphis marsupialis) serum  

Microsoft Academic Search

The South American opossum Didelphis marsupialis is known to be highly resistant to snake envenomation. In this paper it is shown that the opossum serum inhibits haemorrhage induced by both Crotalinae and Viperinae venoms. Tested against Bothrops jararaca (jararaca) venom, the antibothropic complex (ABC) isolated from the opossum serum was at least six times more antihaemorrhagic than the commercial antivenom.

Ana G. C. Neves-Ferreira; Jonas Perales; Michael Ovadia; Haity Moussatché; Gilberto B. Domont

1997-01-01

122

The Historical Anecdotes of Kheng Nobilities  

E-print Network

. But, others consider that Nyakhar Dung left those imprints to mark his victory over a serpent god. The serpent god was hacked into several pieces. These bodies turned into a long stretch of rocks that looked like serpent, and are seen even now...

Dorji, Lham

2005-01-01

123

Optimization of geometry, material and economic parameters of a two-zone subcritical reactor for transmutation of nuclear waste with SERPENT Monte Carlo code  

NASA Astrophysics Data System (ADS)

An optimization study of a subcritical two-zone homogeneous reactor was carried out, taking into consideration geometry, material, and economic parameters. The advantage of a two-zone subcritical system over a single-zone system is demonstrated. The study investigated the optimal volume ratio for the inner and outer zones of the subcritical reactor, in terms of the neutron-physical parameters as well as fuel cost. Optimal geometrical parameters of the system are suggested for different material compositions.

Gulik, Volodymyr; Tkaczyk, Alan Henry

2014-06-01

124

Population genetic structure and geographic differentiation in the hot spring snake Thermophis baileyi (Serpentes, Colubridae): indications for glacial refuges in southern-central Tibet.  

PubMed

The endangered hot spring snake (Thermophis baileyi) is endemic to the Tibetan Plateau and restricted to a few sites at high altitudes (>3500 m a.s.l.). Its strong preference for habitats with hot springs might be an early adaptation to the cooling climate during the plateau uplift. Some of these thermal sites may have been free of ice during the last glacial maximum (LGM) serving as refuges for the snake. To test this and to examine the population genetic structure data of 12 microsatellites and mitochondrial DNA were obtained from 153 individuals from 12 sites across the plateau. Four of the microsatellite loci were newly developed for this study. The results suggest that T. baileyi has at least two genetically diverse clades in Tibet, which developed during the Pleistocene and expanded after the LGM. Accordingly, the existence of separate glacial refuges on the central plateau can be assumed. Analyses of the genetic variation indicated a high level of geographic differentiation and population structure on a regional as well as on a range-wide scale. The study shows that, apart from the phylogeographic signatures, the diversification of current Thermophis populations is caused by (a) a limited dispersal due to mountain ranges, (b) a strong preference for hot springs and (c) the insular distribution of suitable habitats on the plateau. The present data should be taken into account in necessary monitoring and management plans for T. baileyi. PMID:22306823

Hofmann, Sylvia

2012-05-01

125

Redescription of Haemogregarina garnhami (Apicomplexa: Adeleorina) from the blood of Psammophis schokari (Serpentes: Colubridae) as Hepatozoon garnhami n. comb. based on molecular, morphometric and morphologic characters.  

PubMed

Hepatozoon garnhami n. comb. was redescribed from Schokari sand snakes (Psammophis schokari) collected from Riyadh city in Saudi Arabia. Gametocytes were found in the peripheral blood of 2 of 15 snakes examined. Based on the similar morphological and morphometric characteristics, the same host and a similar host habitat environment, it can be concluded for the first time that the present species is conspecific with Haemogregarina garnhami previously reported from Psammophis shokari aegyptius. To further characterize this parasite, the partial 18S rRNA gene was amplified and sequenced. The sequence analysis also showed that Haemogregarina garnhami should be reassigned into the genus Hepatozoon as Hepatozoon garnhami which has 99.5% (859/863 bp) sequence similarity to Hepatozoon ayorgbor, infecting the erythrocytes of Python regius in Ghana. Phylogenetic analysis showed that H. garnhami formed a mixed clade with Hepatozoon spp. from geckos, snakes and rodents and ophidian Hepatozoon spp. did not form a separated phylogenetic unit. Also, Psammophis schokari-infecting Hepatozoon contained several different genetic lineages. To our knowledge, the present work extends the geographic distribution of H. garnhami and is the first report of Hepatozoon infection in snakes from Saudi Arabia. PMID:24827101

Abdel-Baki, Abdel-Azeem S; Al-Quraishy, Saleh; Zhang, J Y

2014-06-01

126

Inferring species trees from gene trees: a phylogenetic analysis of the Elapidae (Serpentes) based on the amino acid sequences of venom proteins.  

PubMed

Toward the goal of recovering the phylogenetic relationships among elapid snakes, we separately found the shortest trees from the amino acid sequences for the venom proteins phospholipase A2 and the short neurotoxin, collectively representing 32 species in 16 genera. We then applied a method we term gene tree parsimony for inferring species trees from gene trees that works by finding the species tree which minimizes the number of deep coalescences or gene duplications plus unsampled sequences necessary to fit each gene tree to the species tree. This procedure, which is both logical and generally applicable, avoids many of the problems of previous approaches for inferring species trees from gene trees. The results support a division of the elapids examined into sister groups of the Australian and marine (laticaudines and hydrophiines) species, and the African and Asian species. Within the former clade, the sea snakes are shown to be diphyletic, with the laticaudines and hydrophiines having separate origins. This finding is corroborated by previous studies, which provide support for the usefulness of gene tree parsimony. PMID:9417893

Slowinski, J B; Knight, A; Rooney, A P

1997-12-01

127

Supplementary Information N. Vidal, J.-C. Rage, A. Couloux, and S.B. Hedges. Snakes (Serpentes). Pp. 390397 in The Timetree of Life, S. B.  

E-print Network

-TTC-YTC-YTK- CTT-GGT-YT-3' (Vidal and Hedges, 2005) for AMEL; BDNF-F, 5'-GAC-CAT-CCT-TTT-CCT-KAC-TAT-GGT-TAT-TTC- ATA-CTT-3' (Noonan and Chippindale, 2006), BDNF-R, 5'-CTA-TCT-TCC-CCT-TTT-AAT-GGT-CAG-TGT-ACA-AAC-3' (Noonan and Chippindale, 2006) for BDNF; NT3-F3, 5'-ATA-TTT-CTG-GCT-TTT-CTC-TGT-GGC-3' (Noonan

Hedges, Blair

128

Temperature adaptation of the heart in the grass snake ( Natrix natrix L.), common European viper ( Vipera berus L.), and steppe viper ( Vipera renardi Christoph) (Reptilia: Squamata: Serpentes)  

Microsoft Academic Search

Changes in the heart rate (HR) in more and less thermophilic reptiles (Natrix natrix L., Vipera berus L., and V. renardi Christoph) exposed to heating from 0 to 40°C under anesthesia have been found to depend on the previous adaptation of the\\u000a animals to the temperature parameters characteristic of the natural habitats of their populations.

I. M. Rutskina; N. A. Litvinov; I. M. Roshchevskaya; M. P. Roshchevskii

2009-01-01

129

A phylogeny of the Lampropeltis mexicana complex (Serpentes: Colubridae) based on mitochondrial DNA sequences suggests evidence for species-level polyphyly within Lampropeltis.  

PubMed

The systematic relationships of snakes in the Lampropeltis mexicana complex (L. mexicana, L. alterna, and L. ruthveni) are poorly known despite several taxonomic studies over the last 80 years. Mitochondrial DNA sequences were used to infer the phylogeny of the L. mexicana complex. At least one representative sample from the nine currently recognized species of Lampropeltis was sequenced. Our results suggest that a deep basal split resulted in the divergence of two groups of Lampropeltis, with one group occupying the upland areas of western United States and most of western and central Mexico, and the other northeastern Mexico and the lowland areas of the southern United States. Results also revealed that the L. mexicana complex and Lampropeltis triangulum are polyphyletic, with taxa from both groups nested together in deeply divergent northern and southern clades. These results are incongruent with previous hypotheses of phylogenetic relationships based on morphology, and suggest that morphological characters shared among the various tri-colored Lampropeltis (e.g., hemipenal structure and tri-colored pattern) may be difficult to interpret phylogenetically. PMID:17270467

Bryson, Robert W; Pastorini, Jennifer; Burbrink, Frank T; Forstner, Michael R J

2007-05-01

130

Effectiveness of phylogenomic data and coalescent species-tree methods for resolving difficult nodes in the phylogeny of advanced snakes (Serpentes: Caenophidia).  

PubMed

Next-generation genomic sequencing promises to quickly and cheaply resolve remaining contentious nodes in the Tree of Life, and facilitates species-tree estimation while taking into account stochastic genealogical discordance among loci. Recent methods for estimating species trees bypass full likelihood-based estimates of the multi-species coalescent, and approximate the true species-tree using simpler summary metrics. These methods converge on the true species-tree with sufficient genomic sampling, even in the anomaly zone. However, no studies have yet evaluated their efficacy on a large-scale phylogenomic dataset, and compared them to previous concatenation strategies. Here, we generate such a dataset for Caenophidian snakes, a group with >2500 species that contains several rapid radiations that were poorly resolved with fewer loci. We generate sequence data for 333 single-copy nuclear loci with ?100% coverage (?0% missing data) for 31 major lineages. We estimate phylogenies using neighbor joining, maximum parsimony, maximum likelihood, and three summary species-tree approaches (NJst, STAR, and MP-EST). All methods yield similar resolution and support for most nodes. However, not all methods support monophyly of Caenophidia, with Acrochordidae placed as the sister taxon to Pythonidae in some analyses. Thus, phylogenomic species-tree estimation may occasionally disagree with well-supported relationships from concatenated analyses of small numbers of nuclear or mitochondrial genes, a consideration for future studies. In contrast for at least two diverse, rapid radiations (Lamprophiidae and Colubridae), phylogenomic data and species-tree inference do little to improve resolution and support. Thus, certain nodes may lack strong signal, and larger datasets and more sophisticated analyses may still fail to resolve them. PMID:25193610

Pyron, R Alexander; Hendry, Catriona R; Chou, Vincent M; Lemmon, Emily M; Lemmon, Alan R; Burbrink, Frank T

2014-12-01

131

Understanding the formation of ancient intertropical disjunct distributions using Asian and Neotropical hinged-teeth snakes (Sibynophis and Scaphiodontophis: Serpentes: Colubridae).  

PubMed

Numerous taxa show ancient intertropical disjunct distributions. Many can be explained by well-known processes of historical vicariance, such as the breakup of Gondwanaland. Others, such as Asian-Neotropical divergences are not as well understood. To clarify the phylogenetic position and understand biogeographic and temporal origins of the geographically disjunct and morphologically unique genera of hinged-teeth snakes, Scaphiodontophis (n=1) and Sibynophis (n=9; Colubridae), we inferred a time-calibrated phylogeny with additional 107 taxa representing the superfamily Colubroidea using four genes (c-mos, cyt-b, ND2, RAG-1; 3085 bp). We used this tree to estimate ancestral areas for the group. The results show that Scaphiodontophis is sister to Sibynophis, both originated in the late Eocene/Oligocene in Asia and likely dispersed through Beringia to the New World, but unlike other snake groups left no extant species in temperate North America. Current recognition of Scaphiodontophiinae renders Colubrinae paraphyletic, and we resurrect the previously named subfamily Sibynophiinae to encompass both genera and use the tribes Sibynophiini (Sibynophis) and Scaphiodontophiini (Scaphiodontophis) to highlight the geographically distinct areas occupied by these taxa. These results suggest that intercontinental dispersal with extinction in intermediate areas can explain puzzling patterns of ancient intertropical disjunct distributions. PMID:23044403

Chen, Xin; Huang, Song; Guo, Peng; Colli, Guarino R; Nieto Montes de Oca, Adrián; Vitt, Laurie J; Pyron, R Alexander; Burbrink, Frank T

2013-01-01

132

A new species of Serpentirhabdias Tkach, Kuzmin & Snyder, 2014 (Nematoda: Rhabdiasidae) parasitic in the brown ground snake Atractus major Boulenger (Reptilia: Serpentes: Dipsadidae) in Brazil.  

PubMed

Serpentirhabdias atracti n. sp. is described based on specimens discovered in the lung of Atractus major Boulenger from Caxiuanã National Forest, Pará, Brazil. The new species is assigned to Serpentirhabdias Tkach, Kuzmin & Snyder, 2014 based on morphological characters (comparatively thin body cuticle without prominent inflations, arrangement of circumoral papillae in two lateral groups, pre-equatorial position of vulva, eggs in uteri at early cleavage stages), as well as because of its parasitism in snakes. The new species is most similar to S. vellardi (Pereira, 1928) due to the absence of lips and buccal capsule, similar body dimensions, and the specificity to dipsadid snakes in Brazil. The two species differ in the shape of the tail (bulbous dilatation in the posterior part followed by a thread-like tail tip present in S. atracti n. sp.), the width of the oesophagus, and the size of the excretory glands. Serpentirhabdias atracti n. sp. is the sixth species of this genus found in the Neotropical Region. PMID:25204597

Kuzmin, Yuriy; Melo, Francisco Tiago de Vasconcelos; dos Santos, Jeannie Nascimento

2014-10-01

133

Isolation, characterization and molecular cloning of AnMIP, a new alpha-type phospholipase A2 myotoxin inhibitor from the plasma of the snake Atropoides nummifer (Viperidae: Crotalinae).  

PubMed

A new phospholipase A(2) (PLA(2))-inhibitory protein was isolated from the plasma of Atropoides nummifer, a crotaline snake from Central America. This inhibitor was named AnMIP, given its ability to neutralize the activity of basic PLA(2) myotoxins of its own and related venoms. The cDNA of AnMIP was cloned and sequenced, showing that it belongs to the alpha group of phospholipase A(2) inhibitors (PLIs). AnMIP appears as a homotrimer in the native state, held together by non-covalent forces, with a subunit molecular mass of 22,247-22,301 and an isoelectric point of 4.1-4.7. This trimeric structure is the first observed in a PLIalpha from American crotaline snakes, previously reported only in Asian species. Sequencing, mass spectrometry, and analytical isoelectrofocusing indicated the existence of isoforms, as reported for other PLIalphas isolated from snake plasma. The inhibitory profile of AnMIP showed specificity towards group II PLA(2)s, either belonging to the catalytically-active (D49) or -inactive (K49) subtypes, exemplified in this study by Bothrops asper myotoxin I and A. nummifer myotoxin II, respectively. By phylogenetic analysis it was shown that AnMIP is closely related to CgMIP-II, previously isolated from the plasma of Cerrophidion godmani, showing 93% amino acid sequence identity. PMID:17071122

Quirós, Steve; Alape-Girón, Alberto; Angulo, Yamileth; Lomonte, Bruno

2007-01-01

134

[Genetic divergence of Vipera berus and Vipera nikolskii (Reptilia: Viperidae, Vipera) populations in lower Volga and adjacent territories assessed according to the sequences of cytochrome oxidase III 12S ribosome RNA genes].  

PubMed

The nucleotide sequences of mitochondrial genome fragments containing the genes coding for cytochrome oxidase subunit III (COIII) and 12S ribosomal RNA of common European viper and Nikolsky's viper from various habitats (Saratov, Samara, and Penza oblasts; Chuvash Republic; and the Republic of Mordovia) were determined. According to the sequencing data, all samples clustered into two groups except for a number of individuals carrying single mutations in the genes in question. One group comprised V. nikolskii from Saratov oblast and the other, V. berus from the Chuvash Republic, Republic of Mordovia, and Samara and Penza oblasts. These results comply with the available data on the karyotypes of the studied vipers of this region. Further genetic studies of V. nikolskii and V. berus from various parts of this area are necessary. PMID:18619049

Efimov, R V; Zav'ialov, E V; Velikov, V A; Tabachishin, V G

2008-02-01

135

Genetic divergence of Vipera berus and Vipera nikolskii (Reptilia: Viperidae, Vipera ) populations in lower Volga and adjacent territories assessed according to the sequences of cytochrome oxidase III and 12S ribosome RNA genes  

Microsoft Academic Search

The nucleotide sequences of mitochondrial genome fragments containing the genes coding for cytochrome oxidase subunit III\\u000a (COIII) and 12S ribosomal RNA of common European viper and Nikolsky’s viper from various habitats (Saratov, Samara, and Penza\\u000a oblasts; Chuvash Republic; and the Republic of Mordovia) were determined. According to the sequencing data, all samples clustered\\u000a into two groups except for a number

R. V. Efimov; E. V. Zav’yalov; V. A. Velikov; V. G. Tabachishin

2008-01-01

136

Block Ciphers and Systems of Quadratic Equations  

Microsoft Academic Search

In this paper we compare systems of multivariate poly- nomials, which completely define the block ciphers Khazad, Misty1, Kasumi, Camellia, Rijndael and Serpent in the view of a potential danger of an algebraic re-linearization attack. Keywords: Block ciphers, multivariate quadratic equations, lineariza- tion, Khazad, Misty, Camellia, Rijndael, Serpent.

Alex Biryukov; Christophe De Cannière

2003-01-01

137

SUBAQUA Mai -Juin 2014 -N 254 39 INFOSRECHERCHE  

E-print Network

, pour capturer un maximum de serpents Tous les deux mois, Stéphan Jacquet, chercheur et moniteur de susceptible d'intéresser les plongeurs que nous sommes. ST�PHAN JACQUET Responsable de rubrique PIERRE LARUE

Jacquet, Stéphan

138

First-Year Family Weekend Schedule  

E-print Network

Clemente Orozco depicted its pyramids and Feathered Serpent in his famous mural cycle, "The Epic and a photographer will take a great picture of your family with the unofficial school mascot, the Dartmoose

Myers, Lawrence C.

139

78 FR 14539 - Notice of Receipt of Pesticide Products; Registration Applications To Register New Uses  

Federal Register 2010, 2011, 2012, 2013, 2014

...common, great-headed, serpent), lily (bulb), onion (bulbs of common, Chinese, pearl, potato), shallot...leek, wild leek, lady's leek, Beltsville bunching onion, fresh onion, green onion, macrostem onion, tree onion...

2013-03-06

140

RICIS Software Engineering 90 Symposium: Aerospace Applications and Research Directions Proceedings  

NASA Technical Reports Server (NTRS)

Papers presented at RICIS Software Engineering Symposium are compiled. The following subject areas are covered: synthesis - integrating product and process; Serpent - a user interface management system; prototyping distributed simulation networks; and software reuse.

1990-01-01

141

Unusual Horizontal Transfer of a Long Interspersed Nuclear Element between Distant Vertebrate Classes  

Microsoft Academic Search

We have shown previously by Southern blot analysis that Bov-B long interspersed nuclear elements (LINEs) are present in different Viperidae snake species. To address the question as to whether Bov-B LINEs really have been transmitted horizontally between vertebrate classes, the analysis has been extended to a larger number of vertebrate, invertebrate, and plant species. In this paper, the evolutionary origin

Dusan Kordis; Franc Gubensek

1998-01-01

142

Molecular Phylogenetics and Evolution 39 (2006) 91110 www.elsevier.com/locate/ympev  

E-print Network

The subfamily Crotalinae (pitvipers) contains over 190 species of venomous snakes distributed in both the Old and their contemporary systematics The venomous snake family Viperidae (asps, moccasins, rattlesnakes, and true vipers bites to humans (e.g., Russell, 1980). Accord- ingly, a valid taxonomy and a robust understanding

Castoe, Todd A.

143

Physiological Responses to Freezing in the Turtle Terrapene carolina Jon P. Costanzo; Richard E. Lee, Jr.; Michael F. Wright  

E-print Network

. Amphibia- Reptilia 12:137-144, -,AND C. ANIBALDI.1991. The diet of the adder (Vipera berus) in two alpine an earlier version of this manuscript. AGRIMI,U.,AND L. LUISELLI.1992. Feeding strategies of the viper Vipera stomacale di Vipera aspis (Reptilia, Viperidae). Hystrix 2:101-107. LUISELLI,L., AND U. AGRIMI.1991

Lee Jr., Richard E.

144

Muscle extract of hedgehog, Erinaceus europaeus, inhibits hemorrhagic activity of snake venoms.  

PubMed

The antihemorrhagic activity of muscle extract of hedgehog, Erinaceus europaeus, was tested on various snake venoms with hemorrhagic activity. The extract inhibited strongly hemorrhagic activity of venoms from Bitis arietans, Bothrops jararaca and Vipera latastei gaditana, and remarkably that of venoms from Agkistrodon halys blomhoffi, Bitis gabonica rhinoceros, Bitis nasicornis, Bothrops atrox asper, Crotalus horridus horridus and Vipera berus. The antihemorrhagic activity against eight other snake venoms was below the detection level. PMID:7846699

Omori-Satoh, T; Nagaoka, Y; Mebs, D

1994-10-01

145

[Studies on hemorrhagic toxins from the venoms of Trimeresurus mucrosquamatus, Crotalus ruber ruber, Vipera aspis aspis and Agkistrodon acutus and arginine ester hydrolases from Trimeresurus mucrosquamatus venom].  

PubMed

Venom samples were corrected from several poisonous snakes, such as Bungarus multicinctus, Trimeresurus mucrosquamatus, T. gramineus, T. flavoviridis, and Agkistrodon acutus, and stored in a desiccator at room temperature for 25 to 31 years. Then they were compared with fresh venoms as to their biological activities. The characteristic local symptoms produced by the bite of venomous snakes of Crotalidae and Viperidae are hemorrhage, necrosis and muscular degeneration. Hemorrhagic toxins were purified from Trimeresurus mucrosquamatus, Crotalus ruber ruber, Vipera aspis aspis, and Agkistrodon acutus venoms and their biological, biochemical, and pathological properties were investigated. Arginine ester hydrolases are present in the venoms of Crotalidae and Viperidae, but are not found in the venoms of Elapidae and Hydrophiidae. In this paper we describe the enzymatic and biological activities of arginine ester hydrolases from a Trimeresurus mucrosquamatus venom. PMID:10774254

Nikai, T; Komori, Y; Sugihara, H

2000-04-01

146

The hypotensive activity of Crotalus atrox (western diamondback rattlesnake) venom: identification of its origin.  

PubMed

Viperidae snakes belonging to the genus Crotalus, subfamily Crotalinae, include the species durissus terrificus, durissus durissus, adamanteus, atrox, cerastes, horridus, molossus, scutulatus, viridis and others. All of them, except for the first 2, are found in North America. Crotalus atrox, or diamondback rattlesnakes, live in the southwest United States and in Mexico. This paper describes the fractionation of C. atrox venom in order to isolate and identify its hypotensive agents. PMID:2035756

de Mesquita, L C; Selistre, H S; Giglio, J R

1991-03-01

147

Snake venom dipeptidyl peptidase IV: Taxonomic distribution and quantitative variation  

Microsoft Academic Search

The present study examined the taxonomic distribution of dipeptidyl peptidase IV (DPP IV) activity in venoms of 59 ophidian taxa, representing seven subfamilies of the Families Elapidae and Viperidae. DPP IV activity is extremely variable at all taxonomic levels. It ranged from essentially none in laticaudine, hydrophiine, and some bungarine and elapine venoms, to 10.72 ?mol 4-methoxy-?-naphthylamine liberated per min per

Steven D. Aird

2008-01-01

148

Molecular evolution of Bov-B LINEs in vertebrates  

Microsoft Academic Search

Since their discovery in family Bovidae (bovids), Bov-B LINEs, believed to be order-specific SINEs, have been found in all ruminants and recently also in Viperidae snakes. The distribution and the evolutionary relationships of Bov-B LINEs provide an indication of their origin and evolutionary dynamics in different species. The evolutionary origin of Bov-B LINE elements has been shown unequivocally to be

Dušan Kordiš; Franc Gubenšek

1999-01-01

149

Positive Darwinian selection in Vipera palaestinae phospholipase A2 genes is unexpectedly limited to the third exon.  

PubMed

The venom of Vipera palaestinae contains a two-component toxin, consisting of an acidic phospholipase A2 (PLA2) and a basic protein. Here we report the cloning and sequence analysis of the complete V. palaestinae PLA2 genes. Since in all Viperidae PLA2 multigene families the 5' and 3' flanking regions are highly conserved, we designed oligonucleotide primers that allow amplification of the whole PLA2 multigene family in a single step. The structural organization of both genes is the same as in the Vipera ammodytes PLA2 multigene family, there being five exons separated by four introns. Comparison of V. palaestinae PLA2 genes with other Viperidae PLA2 genes has shown that the structural organization of the genes and the nucleotide sequence of all introns and flanking regions are highly conserved, whereas the third exon clearly shows a higher number of amino acid replacements, an indication of positive Darwinian selection. The positive Darwinian selection is surprisingly limited to the third exon, in contrast to other Viperidae PLA2 genes, where it is present in all mature protein coding exons. PMID:9792822

Kordis, D; Bdolah, A; Gubensek, F

1998-10-20

150

EVOLUTION DE L'AIRE DE REPARTITION EN FRANCE, EN PARTICULIER AU CENTRE OUEST, CHEZ TROIS SERPENTS : EXTENSION VERS LE NORD (LA COULEUVRE VERTE ET JAUNE, COLUBER VIRIDIFLAVUS LACEPEDE ET LA VIPERE ASPIC, VIPERA ASPIS LINNE) ET REGRESSION VERS LE NORD (LA VIPERE PELIADE, VIPERA BERUS LINNE)  

Microsoft Academic Search

CNRS, Centre d'Etudes Biologiques de Chizé, 79360 Villiers en Bois, FRANCE : E-mail : g_naull@club- internet.fr ABSTRACT.- The northern limit of the area of distribution of Coluber viridiflavus moves to the north. This is clearly observed in the centre-western of France, where during the last forty years, it progressed of almost sixty kilometres toward north, moving extensively to the north

Guy NAULLEAU

2003-01-01

151

Animal Symbols in the Art of the Hodensaunee.  

ERIC Educational Resources Information Center

Explains the significance of the main animal symbols incorporated into the social, cultural, artistic, and spiritual fabric of the Hodenosaunee (the People of the Longhouse) also known as the Six Nations Iroquois: the eagle, turtle, bear, wolf, hawk, heron, snipe, eel, deer, beaver, moose, snake, and serpent. (NEC)

Hill, Richard

1987-01-01

152

A regular look at the marine environment under, on and around offshore installations worldwide Issue 1: April 04  

E-print Network

A regular look at the marine environment under, on and around offshore installations worldwide, but increasing interest and enthusiasm from other offshore personnel and interested staff on land has resulted and the SERPENT Project on board the Transocean drilling rig Jack Bates. This mission is hoped to be the first

National Oceanography Centre, Southampton

153

Mid-American Review of Sociology, Volume 8, Number 2 (WINTER, 1983): Book Review  

E-print Network

Fred Cutter, Art and the Wish to Die: An Analysis of Images of Self Injury in Art from Prehistory to the Present. Chicago: Nelson-Hall, 1983.294 pp. $22.95 (cloth), $11.95 (paper). The mythic image of the serpent Oroboros is an appropriate one...

Hartung, Beth

1983-01-01

154

Lady Kaede in Kurosawa's Ran : verbal and visual characterization through animal traditions  

Microsoft Academic Search

This article deals with the characterization of the unique figure of Lady Kaede in Kurosawa's film Ran from within Japanese cultural syncretism, through using different verbal and visual elements of two animals - fox and serpent. The Japanese fox has always played a most important part in Japanese culture, and its ambivalent nature has become a leitmotiv, especially its supernatural

Zvika Serper

2001-01-01

155

A Little-known Peculiarity of the Hamadryad Snake  

Microsoft Academic Search

A STRUCTURAL peculiarity of the ``king cobra'' which I have recently ascertained while studying the anatomy of the Ophidia seems to me to be so remarkable that it must have been noticed in such comprehensive works as Bronn's ``Thierreich'' and Dr. Gadow's account of serpents in the ``Cambridge Natural History'' were it known. I venture, therefore, to give a short

Frank E. Beddard

1903-01-01

156

Herpetologywww.harding.edu/plummer/herp/home.pdf (Updated 7 May 2012) Careers in Herpetology | Center for North American Herpetology | Prospective Students  

E-print Network

2008 Turts&lizards_2 Field Trips 2010 Snakes_1 Field Trips 2012 Snakes_2 Voluntary snake bite 2010 Snakes_3 AR Salamanders AR Frogs AR Frog Calls AR Alligator AR Turtles AR Lizards AR Snakes Old Exam (lizards) - 5537 species Suborder Serpentes (snakes) - 3346 species Suborder Amphisbaenia (worm lizards

Plummer, Michael V.

157

CYRANO CAST LIST: All Cast members need to be measured in the costume shop before semester break. Please  

E-print Network

CYRANO CAST LIST: All Cast members need to be measured in the costume shop before semester break: Anna Morreale #12;The Serpent Lady Cast List FARRUSCAD; Casey James CHERESTANI; Adia Alli CANZADE/s CHERESTANI); Katherine Schooler FULMINA; Jenna Jo Pawlicki TERRAMOTA; Marley Boone Peter Pan Cast List PETER

Liu, Taosheng

158

In the Womb of the Earth: Sex in the Maya Cave Setting  

E-print Network

:211 n. 6) and in al probability, speleothems were thought of as the fangs of cave mouths among the ancient Maya (Saturno, et al. 2005:14). 21 Also, mouths of beasts, such as those of jaguars, saurians, and serpents, are common in Mesoamerican art...

Saffa, Sarah Nicole

2009-08-28

159

Jennell M. Miller, Ph.D. Educational Background  

E-print Network

Molecular Biology, 11(1) 67-77 Abdominal-B serves as a developmental switch between dorsal fat and visceral Bernardino serpent, a GATA-like transcription factor gene, induces fat-cell development in Drosphila 111; Issue 1-2, 173-176 Identification of fat-cell enhancer regions in Drosophila melanogaster. (2002

Hoshizaki, Deborah K.

160

Contemporary Earth System Science A lecture and discussion colloquium course for early-career undergraduate students interested  

E-print Network

Sept: Julie Cole: Global warming's evil twin: Ocean acidification and its ecosystem impacts 9 Sept? 16 Sept: Joellen Russell: The once and future battles of Thor and the Midgard Serpent or: The ocean Can Paleoclimate Records Tell Us About Human Evolution? 9 Dec: Final Papers due for Section 002H

Reiners, Peter W.

161

www.serpentproject.com issue 15: sept 2008  

E-print Network

SERPENT www.serpentproject.com issue 15: sept 2008 FRS Marine Laboratory collaboration of ROV footage from pipelines and structural inspections and ad hoc Baited Underwater Camera (BUCD student Iñigo Martinez and FRS Marine Laboratory technician Martin Burns visited the Buzzard Field

National Oceanography Centre, Southampton

162

Identification of Keys and Cryptographic Algorithms Using Genetic Algorithm and Graph Theory  

Microsoft Academic Search

This paper describes genetic algorithms that use the Calisnki-Harabasz index as its evaluation function and graphs techniques that are both used to identify patterns in cryptograms generated by cryptographics algorithms certified by NIST (National Institute Standard Technology), namely AES, RC6, MARS, Twofish and Serpent. Evidence of patterns or \\

Jose Xexeo; William Souza; Renato Torres; Glaucio Oliveira; Ricardo Linden

2011-01-01

163

Frequency and effort of reproduction in female Vipera aspis from a southern population  

NASA Astrophysics Data System (ADS)

The frequency of reproduction of the asp viper ( Vipera aspis, Viperidae) was studied in a population living along the coasts of central Italy. An annual reproductive cycle seemed to be the rule during the 5-year study period. Annual reproduction, high average mass of reproductive females, and large size of neonates, compared with other northern or continental populations, are presumably due to the particularly suitable climatic conditions of the area, as in most coastal habitats of the Mediterranean region. Such a scenario should influence the extent of the feeding period, which allows females, within a few months after parturition, to regain their previous body condition and reproduce again the following year.

Zuffi, Marco A. L.; Giudici, Federico; Ioalè, Paolo

1999-11-01

164

The Bov-B lines found in Vipera ammodytes toxic PLA2 genes are widespread in snake genomes.  

PubMed

In the fourth intron of two toxic Vipera ammodytes PLA2 genes a Ruminantia specific 5'-truncated Bov-B LINE element was identified. Southern blot analysis of Bov-B LINE distribution in vertebrates shows that, apart from the Ruminantia, it is limited to Viperidae snakes (V. ammodytes, Vipera palaestinae, Echis coloratus, Bothrops alternatus, Trimeresurus flavoviridis and Trimeresurus gramineus). The copy number of the 3' end of Bov-B LINE in the V. ammodytes genome is between 62,000 and 75,000. At orthologous positions in other snake PLA2 genes the Bov-B LINE element is absent, indicating that its retrotransposition in the V. ammodytes PLA2 gene locus has occurred quite recently, about 5 Myr ago. The amplification of Bov-B LINEs in snakes may have occurred before the divergence of the Viperinae and Crotalinae subfamilies. Due to its wide distribution in Viperidae snakes it should be a valuable phylogenetic marker. The neighbour-joining phylogenetic tree shows two clusters of truncated Bov-B LINE, a Bovidae and a snake cluster, indicating an early horizontal transfer of this transposable element. PMID:9792174

Kordis, D; Gubensek, F

1998-11-01

165

Structural characteristics and evolution of a novel venom phospholipase A2 gene from Protobothrops flavoviridis.  

PubMed

A novel phospholipase A(2) (PLA(2)) gene, named PfPLA 6, was found in a 6,328-bp NIS-1(5')-a segment in the Protobothrops flavoviridis (Habu, Crotalinae) genome. A comparison of the aligned nucleotide sequences of Viperidae (Viperinae and Crotalinae) venom PLA(2) genes, including PfPLA 6, revealed the deletion of a 12-bp segment called S1EX 1 and a 55-bp segment called S2EX 1 in exon 1 and the interposition of a 219-bp segment called SINT 2 (SINE) in intron 2. A classification of Viperidae PLA(2) genes based on these structural modes indicated that the A-type genes (without SINE), including PfPLA 6, are evolutionarily ancestral to the B-type (Viperinae) and C-type (Crotalinae) PLA(2) genes (both with SINE). Since PfPLA 6 is a pseudogene, an active prototype of PfPLA 6 can be assumed to be the ancestral PLA(2) gene. Putative evolutionary processes from this A-type prototype PLA(2) gene to descendent PLA(2) genes are discussed. PMID:22451399

Chijiwa, Takahito; Ikeda, Naoki; Masuda, Haruna; Hara, Hiroaki; Oda-Ueda, Naoko; Hattori, Shosaku; Ohno, Motonori

2012-01-01

166

Snakebites in Hungary--epidemiological and clinical aspects over the past 36 years.  

PubMed

Epidemiological and clinical aspects of snakebites in Hungary between 1970 and 2006 were surveyed. A total of 97 cases were recorded from 21 species, including the two native vipers, Vipera berus and Vipera ursinii, and various exotic species represented by Viperidae, Elapidae, and Colubridae. Bites by native species on laymen are uncommon (17 cases) and present trivial clinical manifestations. Compared with the consequences of native Vipera cases, bites by exotic species often resulted in severe or life-threatening envenomations. These cases were treated with antivenom administration, plasmapheresis, fasciotomy, and amputation. There were two fatalities caused by V. berus and Agkistrodon contortrix. Both of these cases were inflicted in snake-handlers with a previous history of Viperidae bites and the cause of deaths are attributed to anaphylactic reactions as a consequence of hypersensitivity to the venom. Snake-handlers and their physicians face a major challenge due to the diversity and severity of signs and symptoms following exotic venomous snakebites, and the risk of anaphylaxis or anaphylactoid reactions in patients with repeated exposure to snake venom and antivenom. Highly dangerous venomous snake species continue to appear in collections of Hungarian snake-handlers. PMID:18241904

Malina, Tamás; Krecsák, László; Korsós, Zoltán; Takács, Zoltán

2008-05-01

167

The history of the evil eye and its influence on ophthalmology, medicine and social customs  

Microsoft Academic Search

Belief in the evil eye is one of the oldest and most widespread superstitions in the world. The concept of the evil eye has\\u000a influenced present day ophthalmology, medicine, and social customs. Oculus sinister (OS), the serpent and the staff of Asclepius,\\u000a the symbol of RX, and many social customs are historically related to the evil eye.

George H. Bohigian

1997-01-01

168

Dyke swarm emplacement in the Ethiopian Large Igneous Province: not only a matter of stress  

Microsoft Academic Search

In the Tana–Belaya area, western Ethiopia, field data and satellite imagery reveal the existence of two dyke swarms, the NE–SW Serpent-God dyke swarm, and the NW–SE Dinder dyke swarm. Both swarms are thought to have the same age, 30 Ma, and are likely to have contributed to feeding the traps. After a description of the swarms, this paper examines their

Daniel Mège; Tesfaye Korme

2004-01-01

169

Dyke swarm emplacement in the Ethiopian Large Igneous Province: not only a matter of stress  

Microsoft Academic Search

In the Tana^Belaya area, western Ethiopia, field data and satellite imagery reveal the existence of two dyke swarms, the NE^SW Serpent-God dyke swarm, and the NW^SE Dinder dyke swarm. Both swarms are thought to have the same age, 30 Ma, and are likely to have contributed to feeding the traps. After a description of the swarms, this paper examines their

Daniel Me; Tesfaye Korme

170

The Sunlight Effect of the Kukulcán Pyramid or The History of a Line  

Microsoft Academic Search

When the sunlight bathes the Kukulcán Pyramid in the Mayan city of Chichén-Itzá during the equinox sunset, it casts seven\\u000a triangles of light and shadow that creep downwards along its northeast stairway. According to the Popol Vuh, the effect can be interpreted as the myth of the gods of the Heart of Sky coming to the Sovereign Plumed Serpent. Unfortunately,

Tomás García-Salgado

2010-01-01

171

Anthropology's histories: Dealing with time and transformation in the pacific  

Microsoft Academic Search

Battaglia, Debbora. On the Bones of the Serpent: Person, Memory and Mortality in Sabarl Island Society. Chicago: University of Chicago Press, 1990. x + 252 pp. including appendix, notes, references, and index. $41.00 cloth, $14.95 paper.Biersack, Aletta, ed. Clio in Oceania: Toward a Historical Anthropology. Washington, D.C.: Smithsonian Institution Press, 1991. vii + 383 pp. including chapter references. $37.40 cloth.Damon,

Martha Macintyre

1994-01-01

172

Ophiuchus  

NASA Astrophysics Data System (ADS)

(the Serpent-bearer; abbrev. Oph, gen. Ophiuchi; area 948 sq. deg.) An equatorial constellation which lies between Hercules and Scorpius, and culminates at midnight in mid-June. The ecliptic cuts across the southern part of Ophiuchus, but the constellation is not included among the constellations of the zodiac. Ophiuchus is usually said to represent Asclepius, the Greek god of medicine, and is sh...

Murdin, P.

2000-11-01

173

Does prey size induce head skeleton phenotypic plasticity during early ontogeny in the snake Boa constrictor ?  

Microsoft Academic Search

Diet was manipulated in juveniles of the snakeBoaconstrictor (Serpentes: Boidae) to test the hypothesis of whether prey size induces phenotypic plasticity of the head skeleton. Additionally, the onset of sexual size dimorphisms (SSDs) was determined under a feeding schedule where total prey mass consumed by snakes was held constant. Twenty-three neonatalB. constrictor from a single-sired litter were placed into two

Gordon W. Schuett; David L. Hardy Sr; Ryan L. Earley; Harry W. Greene

2005-01-01

174

Computation of a Canadian SCWR unit cell with deterministic and Monte Carlo codes  

SciTech Connect

The Canadian SCWR has the potential to achieve the goals that the generation IV nuclear reactors must meet. As part of the optimization process for this design concept, lattice cell calculations are routinely performed using deterministic codes. In this study, the first step (self-shielding treatment) of the computation scheme developed with the deterministic code DRAGON for the Canadian SCWR has been validated. Some options available in the module responsible for the resonance self-shielding calculation in DRAGON 3.06 and different microscopic cross section libraries based on the ENDF/B-VII.0 evaluated nuclear data file have been tested and compared to a reference calculation performed with the Monte Carlo code SERPENT under the same conditions. Compared to SERPENT, DRAGON underestimates the infinite multiplication factor in all cases. In general, the original Stammler model with the Livolant-Jeanpierre approximations are the most appropriate self-shielding options to use in this case of study. In addition, the 89 groups WIMS-AECL library for slight enriched uranium and the 172 groups WLUP library for a mixture of plutonium and thorium give the most consistent results with those of SERPENT. (authors)

Harrisson, G.; Marleau, G. [Inst. of Nuclear Engineering, Ecole Polytechnique de Montreal (Canada)

2012-07-01

175

Structure and Function of Snake Venom Proteins Affecting Platelet Plug Formation  

PubMed Central

Many snake venom proteins have been isolated that affect platelet plug formation by interacting either with platelet integrins, membrane glycoprotein Ib (GPIb), or plasma von Willebrand factor (VWF). Among them, disintegrins purified from various snake venoms are strong inhibitors of platelet aggregation. Botrocetin and bitiscetin derived from Bothrops jararaca and Bitis arietans venom, respectively, induce VWF-dependent platelet agglutination in vitro. Several GPIb-binding proteins have also been isolated from snake venoms. In this review, we focus on the structure and function of those snake venom proteins that influence platelet plug formation. These proteins are potentially useful as reagents for the sub-diagnosis of platelet disorder or von Willebrand disease, as well as for clinical and basic research of thrombosis and hemostasis. PMID:22069544

Matsui, Taei; Hamako, Jiharu; Titani, Koiti

2009-01-01

176

Fast analysis of low molecular mass compounds present in snake venom: identification of ten new pyroglutamate-containing peptides.  

PubMed

Characterization of the peptide content in snake venoms can be an important tool for the investigation of new pharmacological lead compounds. For this purpose, single-step analysis of crude venoms has recently been demonstrated using mass spectrometry (MS) techniques. Reproducible profiles of ions in MS and MS/MS spectra may also be used to compare venoms from different species. In this work matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) was used to obtain mass patterns of the major peptides (<8 kDa) found in pooled venoms from the genera Bothrops and Crotalus. Venoms from five different Bothrops species (B. jararaca, B. insularis, B. alternatus, B. jararacussu, and B. neuwiedi) and three Crotalus species (C. viridis, C. adamanteus and C. durissus terrificus) were analyzed. In agreement with other reports, venoms from Bothrops species contained a variety of peptides in the range m/z 1000-1500, and in some samples larger components (m/z 7000-8000) were detected. In the Crotalus species venoms were rich in peptides ranging from m/z 1000-1500 and 4000-5500. MS/MS experiments on the low molecular mass peptides (m/z 1000-1500) confirmed the presence of ten new bradykinin-potentiating peptides among venoms from genera Bothrops and Crotalus. In order to determine whether additional peptides could be identified after partial purification, B. jararaca venom was subjected to size-exclusion chromatography on Sephacryl S-200, and two distinct low molecular mass pools were analyzed further by MALDI-TOFMS. No additional peptides were detected from the pool with masses below 2000 Da but a substantial improvement with better resolution was observed for the pool with masses above 7000 Da, indicating that complex samples such as crude snake venoms can be analyzed for low molecular mass peptides using a single-step procedure. PMID:15912471

Wermelinger, Luciana Serrão; Dutra, Denis L S; Oliveira-Carvalho, Ana L; Soares, Márcia Regina; Bloch, Carlos; Zingali, Russolina B

2005-01-01

177

Antitumoral Potential of Tunisian Snake Venoms Secreted Phospholipases A2  

PubMed Central

Phospholipases type A2 (PLA2s) are the most abundant proteins found in Viperidae snake venom. They are quite fascinating from both a biological and structural point of view. Despite similarity in their structures and common catalytic properties, they exhibit a wide spectrum of pharmacological activities. Besides being hydrolases, secreted phospholipases A2 (sPLA2) are an important group of toxins, whose action at the molecular level is still a matter of debate. These proteins can display toxic effects by different mechanisms. In addition to neurotoxicity, myotoxicity, hemolytic activity, antibacterial, anticoagulant, and antiplatelet effects, some venom PLA2s show antitumor and antiangiogenic activities by mechanisms independent of their enzymatic activity. This paper aims to discuss original finding against anti-tumor and anti-angiogenic activities of sPLA2 isolated from Tunisian vipers: Cerastes cerastes and Macrovipera lebetina, representing new tools to target specific integrins, mainly, ?5?1 and ?v integrins. PMID:23509718

Zouari-Kessentini, Raoudha; Srairi-Abid, Najet; Bazaa, Amine; El Ayeb, Mohamed; Luis, Jose; Marrakchi, Naziha

2013-01-01

178

Wide distribution of cysteine-rich secretory proteins in snake venoms: isolation and cloning of novel snake venom cysteine-rich secretory proteins.  

PubMed

Cysteine-rich secretory proteins (CRISPs) are found in epididymis and granules of mammals, and they are thought to function in sperm maturation and in the immune system. Recently, we isolated and obtained clones for novel snake venom proteins that are classified as CRISP family proteins. To elucidate the distribution of snake venom CRISP family proteins, we evaluated a wide range of venoms for immuno-cross-reactivity. Then we isolated, characterized, and cloned genes for three novel CRISP family proteins (piscivorin, ophanin, and catrin) from the venom of eastern cottonmouth (Agkistrodon piscivorus piscivorus), king cobra (Ophiophagus hannah), and western diamondback rattlesnake (Crotalus atrox). Our results show the wide distribution of snake venom CRISP family proteins among Viperidae and Elapidae from different continents, indicating that CRISP family proteins compose a new group of snake venom proteins. PMID:12646276

Yamazaki, Yasuo; Hyodo, Fumiko; Morita, Takashi

2003-04-01

179

Venomous snakebites.  

PubMed

More than 5 million people are bitten by venomous snakes annually and more than 100,000 of them die. In Europe, one person dies due to envenomation every 3 years. There is only one venomous snake species in Lithuania--the common adder (Vipera berus)--which belongs to the Viperidae family; however, there are some exotic poisonous snakes in the zoos and private collections, such as those belonging to the Elapidae family (cobras, mambas, coral snakes, etc.) and the Crotalidae subfamily of the Viperidae family (pit vipers, such as rattlesnakes). Snake venom can be classified into hemotoxic, neurotoxic, necrotoxic, cardiotoxic, and nephrotoxic according to the different predominant effects depending on the family (i.e., venom of Crotalidae and Viperidae snakes is more hemotoxic and necrotoxic, whereas venom of Elapidae family is mainly neurotoxic). The intoxication degree is estimated according to the appearance of these symptoms: 1) no intoxication ("dry" bite); 2) mild intoxication (local edema and pain); 3) moderate intoxication (pain, edema spreading out of the bite zone, and systemic signs); 4) severe intoxication (shock, severe coagulopathy, and massive edemas). This topic is relevant because people tend to make major mistakes providing first aid (e.g., mouth suction, wound incision, and application of ice or heat). Therefore, this article presents the essential tips on how first aid should be performed properly according to the "Guidelines for the Management of Snake-Bites" by the World Health Organization (2010). Firstly, the victim should be reassured. Rings or other things must be removed preventing constriction of the swelling limb. Airway/breathing must be maintained. The bitten limb should be immobilized and kept below heart level to prevent venom absorption and systemic spread. Usage of pressure bandage is controversial since people usually apply it improperly. Incision, mouth suction, or excision should not be performed; neither a tourniquet nor ice or heat should be applied. A doctor must monitor respiratory rate, blood pressure, heart rate, renal function, fluid balance, and coagulation status. The only specific treatment method is antivenin--serum with antibodies against antigens of snake venom. Antivenins against pit vipers used in the United States are Antivenin Crotalidae Polyvalent (ACP) and a more purified and hence causing less adverse reactions--Crotalidae Polyvalent Immune Fab (CroFab). In Europe, a polyvalent antiserum against Viperidae family snakes (including the common adder) can be used. Antivenins often may cause severe hypersensitivity reactions because of their protein nature. The bite of the common adder (the only poisonous snake in such countries as Lithuania and Great Britain) relatively rarely results in death; thus, considering the risk of dangerous reactions the antivenin causes itself, the usage of it is recommended to be limited only to life-threatening conditions. PMID:22123554

Adukauskien?, Dalia; Varanauskien?, Egl?; Adukauskait?, Agn?

2011-01-01

180

Current challenges for confronting the public health problem of snakebite envenoming in Central America  

PubMed Central

Snakebite envenoming is a serious public health problem in Central America, where approximately 5,500 cases occur every year. Panama has the highest incidence and El Salvador the lowest. The majority, and most severe, cases are inflicted by the pit viper Bothrops asper (family Viperidae), locally known as ‘terciopelo’, ‘barba amarilla’ or ‘equis’. About 1% of the bites are caused by coral snakes of the genus Micrurus (family Elapidae). Despite significant and successful efforts in Central America regarding snakebite envenomings in the areas of research, antivenom manufacture and quality control, training of health professionals in the diagnosis and clinical management of bites, and prevention of snakebites, much remains to be done in order to further reduce the impact of this medical condition. This essay presents seven challenges for improving the confrontation of snakebite envenoming in Central America. Overcoming these challenges demands a coordinated partnership of highly diverse stakeholders though inter-sectorial and inter-programmatic interventions. PMID:24602234

2014-01-01

181

Comparative Sex Chromosome Genomics in Snakes: Differentiation, Evolutionary Strata, and Lack of Global Dosage Compensation  

PubMed Central

Snakes exhibit genetic sex determination, with female heterogametic sex chromosomes (ZZ males, ZW females). Extensive cytogenetic work has suggested that the level of sex chromosome heteromorphism varies among species, with Boidae having entirely homomorphic sex chromosomes, Viperidae having completely heteromorphic sex chromosomes, and Colubridae showing partial differentiation. Here, we take a genomic approach to compare sex chromosome differentiation in these three snake families. We identify homomorphic sex chromosomes in boas (Boidae), but completely heteromorphic sex chromosomes in both garter snakes (Colubridae) and pygmy rattlesnake (Viperidae). Detection of W-linked gametologs enables us to establish the presence of evolutionary strata on garter and pygmy rattlesnake sex chromosomes where recombination was abolished at different time points. Sequence analysis shows that all strata are shared between pygmy rattlesnake and garter snake, i.e., recombination was abolished between the sex chromosomes before the two lineages diverged. The sex-biased transmission of the Z and its hemizygosity in females can impact patterns of molecular evolution, and we show that rates of evolution for Z-linked genes are increased relative to their pseudoautosomal homologs, both at synonymous and amino acid sites (even after controlling for mutational biases). This demonstrates that mutation rates are male-biased in snakes (male-driven evolution), but also supports faster-Z evolution due to differential selective effects on the Z. Finally, we perform a transcriptome analysis in boa and pygmy rattlesnake to establish baseline levels of sex-biased expression in homomorphic sex chromosomes, and show that heteromorphic ZW chromosomes in rattlesnakes lack chromosome-wide dosage compensation. Our study provides the first full scale overview of the evolution of snake sex chromosomes at the genomic level, thus greatly expanding our knowledge of reptilian and vertebrate sex chromosomes evolution. PMID:24015111

Zektser, Yulia; Mahajan, Shivani; Bachtrog, Doris

2013-01-01

182

The World of Dark Shadows Issue 31  

E-print Network

. and the Serpent", "B . Q. and the Mummy' 5 Curse". If you'd like one, send remittance to me, and the book will be forwarded on to you. Richard Clark made the following suggestion--If you spread the word about OS by having a letter to the editor printed about... it in newsstand magazines (such as monster or soap opera magazines), send me a copy of the published letter and your sub will be extended by one issue . TELEFILM PROJECT As mentioned last issue, a Los Angeles-based production company is considering...

Multiple Contributors

1982-01-01

183

Astronomy at Teotihuacan  

NASA Astrophysics Data System (ADS)

Located 37 km from Mexico City, during the first part of the first millennium AD, Teotihuacan was one of the world's largest and most populated cities. The city controlled the obsidian mines and developed far-reaching economic and political interactions, especially with the Classic Maya dynasties, Monte Albán in the Valley of Oaxaca and the Mexican Gulf Coast. Teotihuacan-made pottery and jewelry along with talud-tablero architectural style and the cult of the Feathered Serpent and Rain gods was spread throughout Mesoamerica.

Iwaniszewski, Stanis?aw

184

A review of "Shifting Contexts: Reinterpreting Samson Agonistes" by Joseph Wittreich  

E-print Network

to minimize the praise in Hebrews: instead one should recognize a serpentine Samson who with his Danite relatives perished because of the evils foreseen by Jacob. Here too is the source of the strange ?evening Dragon? that appears near the end of the play..., dragons and serpents being nearly synonymous (252). REVIEWS 23 Such a view makes possible an entirely new understanding of Milton?s Samson with concomitant revaluations of the entire play in its shifting contexts that Wittreich investigates and invites his...

William B. Hunter

2003-01-01

185

Fish Fingers and Custard Issue 9  

E-print Network

the legacy of the show, which certainly puts him up in my estimation! In recent years, Tom did a u-turn and reprised his role for BBC Audio, to play The Doctor in The Nest Cottage stories - Hornets Nest, Demon Quest and Serpents Crest. These stories... Issue 9 18 country’, as Paul Castle wrote for Shooty Dog Thing (6b Or Not 6b?, 2010). Continuity Error Why do we have a Season 6B in the first place? Where did these continuity errors come from, and why? Sadly, the answers are lost...

2012-01-01

186

Literary reviews  

Microsoft Academic Search

Thinly?veiled autobiographyThe Enigma of Arrival. V S Naipaul, London: Viking. 1987. 318pp. £10.95hbUnmasking MexicoThe Good Conscience. Carlos Fuentes, London: André Deutsch. 1986. 148pp. £8.95hb\\/£3.95pbA Change of Skin. Carlos Fuentes, London: André Deutsch. 1986. 462pp. £6.95pbThe Old Gringo. Carlos Fuentes, London: André Deutsch. 1986. 199pp. £8.95Alternative realities: novels from BrazilDona Flor and Her Two Husbands. Jorge Amado, London: Serpent's Tail. 1986.

Johnt Hieme; Jason Wilson; Amanda Hopkinson; Nissa Torrents; Judie Newman; Maria Couto; William Walsh; Fadia A Faqir; M. M. Badawi; Shahrukh A Husain

1987-01-01

187

Spectroscopy of Moses Rock Kimberlite Diatreme  

NASA Technical Reports Server (NTRS)

Three types of remote sensing data (Airborne Imaging Spectroscopy (AIS), NS001, Zeiss IR-photographs) were obtained for the Moses Rock kimberlite dike in southern Utah. The goal is to identify and characterize the mantle derived mafic component in such volcanic features. The Zeiss and NS001 images provide information on the regional setting and allow units of the dike to be distinguished from surrounding material. A potential unmapped satellite dike was identified. The AIS data provide characterizing information of the surface composition of the dike. Serpentized olivine-bearing soils are (tentatively) identified from the AIS spectra for a few areas within the dike.

Pieters, C. M.; Mustard, J. F.

1985-01-01

188

Improved Neutronics Treatment of Burnable Poisons for the Prismatic HTR  

SciTech Connect

In prismatic block High Temperature Reactors (HTR), highly absorbing material such a burnable poison (BP) cause local flux depressions and large gradients in the flux across the blocks which can be a challenge to capture accurately with traditional homogenization methods. The purpose of this paper is to quantify the error associated with spatial homogenization, spectral condensation and discretization and to highlight what is needed for improved neutronics treatments of burnable poisons for the prismatic HTR. A new triangular based mesh is designed to separate the BP regions from the fuel assembly. A set of packages including Serpent (Monte Carlo), Xuthos (1storder Sn), Pronghorn (diffusion), INSTANT (Pn) and RattleSnake (2ndorder Sn) is used for this study. The results from the deterministic calculations show that the cross sections generated directly in Serpent are not sufficient to accurately reproduce the reference Monte Carlo solution in all cases. The BP treatment produces good results, but this is mainly due to error cancellation. However, the Super Cell (SC) approach yields cross sections that are consistent with cross sections prepared on an “exact” full core calculation. In addition, very good agreement exists between the various deterministic transport and diffusion codes in both eigenvalue and power distributions. Future research will focus on improving the cross sections and quantifying the error cancellation.

Y. Wang; A. A. Bingham; J. Ortensi; C. J. Permann

2012-10-01

189

Mars Hand Lens Imager (MAHLI) Efforts and Observations at the Rocknest Eolian Sand Shadow in Curiosity's Gale Crater Field Site  

NASA Technical Reports Server (NTRS)

The Mars Science Laboratory (MSL) mission is focused on assessing the past or present habitability of Mars, through interrogation of environment and environmental records at the Curiosity rover field site in Gale crater. The MSL team has two methods available to collect, process and deliver samples to onboard analytical laboratories, the Chemistry and Mineralogy instrument (CheMin) and the Sample Analysis at Mars (SAM) instrument suite. One approach obtains samples by drilling into a rock, the other uses a scoop to collect loose regolith fines. Scooping was planned to be first method performed on Mars because materials could be readily scooped multiple times and used to remove any remaining, minute terrestrial contaminants from the sample processing system, the Collection and Handling for In-Situ Martian Rock Analysis (CHIMRA). Because of this cleaning effort, the ideal first material to be scooped would consist of fine to very fine sand, like the interior of the Serpent Dune studied by the Mars Exploration Rover (MER) Spirit team in 2004 [1]. The MSL team selected a linear eolian deposit in the lee of a group of cobbles they named Rocknest (Fig. 1) as likely to be similar to Serpent Dune. Following the definitions in Chapter 13 of Bagnold [2], the deposit is termed a sand shadow. The scooping campaign occurred over approximately 6 weeks in October and November 2012. To support these activities, the Mars Hand Lens Imager (MAHLI) acquired images for engineering support/assessment and scientific inquiry.

Edgett, K. S.; Yingst, R. A.; Minitti, M. E.; Goetz, W.; Kah, L. C.; Kennedy, M. R.; Lipkaman, L. J.; Jensen, E. H.; Anderson, R. C.; Beegle, L. W.; Carsten, J. L.; Cooper, B.; Deen, R. G.; Dromart, G.; Eigenbrode, J. L.; Grotzinger, J. P.; Gupta, S.; Hamilton, V. E.; Hardgrove, C. J.; Harker, D. E.; Herkenhoff, K. E.; Herrera, P. N.; Hurowitz, J. A.; Jandura, L.; Ming, D. W.

2013-01-01

190

Explicit temperature treatment in Monte Carlo neutron tracking routines - First results  

SciTech Connect

This article discusses the preliminary implementation of the new explicit temperature treatment method to the development version Monte Carlo reactor physics code Serpent 2 and presents the first practical results calculated using the method. The explicit temperature treatment method, as introduced in [1], is a stochastic method for taking the effect of thermal motion into account on-the-fly in a Monte Carlo neutron transport calculation. The method is based on explicit treatment of the motion of target nuclei at collision sites and requires cross sections at 0 K temperature only, regardless of the number of temperatures in the problem geometry. The method includes a novel capability of modelling continuous temperature distributions. Test calculations are performed for two test cases, a PWR pin-cell and a HTGR system. The resulting k{sub eff} and flux spectra are compared to a reference solution calculated using Serpent 1.1.16 with Doppler-broadening rejection correction [2]. The results are in very good agreement with the reference and also the increase in calculation time due to the new method is on acceptable level although not fully insignificant. On the basis of the current study, the explicit treatment method can be considered feasible for practical calculations. (authors)

Tuomas, V.; Jaakko, L. [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT (Finland)

2012-07-01

191

Diving Down in Partnership - Technology assists science outreach  

NASA Astrophysics Data System (ADS)

Advances in underwater technology are revealing a world hitherto unseen - the deep ocean. Advances in web technology are enabling scientists to share their discoveries with the world. Underwater robot cameras are allowing scientists to observe animal behaviour and study habitats at depths of 6000 metres. And the Internet is providing a window on this exotic world for everyone with access to the web. The UK's National Oceanography Centre, Southampton operates Isis, a scientific deep-diving remotely-operated vehicle (ROV). The results are phenomenal, producing footage of life in the abyss and the ability to take samples and conduct experiments on the ocean floor. The Centre also hosts a novel project making use of the robot cameras used in the oil and gas industry for maintenance and exploration. Scientists are using this equipment during stand-by time to study animals in their own habitat. The SERPENT project - Scientific and Environmental ROV Partnership using Existing industrial Technology - is an international collaboration with industry, academia and museums. The SERPENT website is updated with the latest information and images attracting some 2000 visitors a month, which is set to rise with recent web developments. A vital part of the Centre's role is communication with the public to increase awareness of the marine environment. Images are essential for outreach especially as audiences continue to seek pictures from remote and inaccessible locations. This talk will explore how TV and the Internet are changing science outreach and the new challenges that it brings.

Marshall-Brown, K.

2009-04-01

192

Diagnostic uses of snake venom.  

PubMed

Snake venom toxins are invaluable for the assay of coagulation factors and for the study of haemostasis generally. Thrombin-like enzymes (SVTLE) are used for fibrinogen and fibrinogen breakdown product assays as well as detecting dysfibrinogenaemias. Since SVTLE are not inhibited by heparin, they can be used for assaying antithrombin III in samples containing heparin. Snake venom prothrombin activators are utilised in prothrombin assays, whilst Russell's viper venom (RVV) can be used to assay clotting factors V, VII, X and lupus anticoagulants (LA). Activators from the taipan, Australian brown snake and saw-scaled viper have also been used to assay LA. Protein C (PC) and activated PC (APC) resistance can be measured by means of RVV, Protac (from Southern copperhead snake venom) and STA-Staclot (from Crotalus viridis helleri) whilst von Willebrand factor can be studied with Botrocetin (Bothrops jararaca). Finally, snake venom C-type lectins and metalloproteinase disintegrins are being used to study platelet glycoprotein receptors and show great potential for use in the routine coagulation laboratory. PMID:11910187

Marsh, N A

2001-01-01

193

Transcriptome analysis of the Amazonian viper Bothrops atrox venom gland using expressed sequence tags (ESTs).  

PubMed

Bothrops atrox is a highly dangerous pit viper in the Brazilian Amazon region. We produced a global catalogue of gene transcripts to identify the main toxin and other protein families present in the B. atrox venom gland. We prepared a directional cDNA library, from which a set of 610 high quality expressed sequence tags (ESTs) were generated by bioinformatics processing. Our data indicated a predominance of transcripts encoding mainly metalloproteinases (59% of the toxins). The expression pattern of the B. atrox venom was similar to Bothrops insularis, Bothrops jararaca and Bothrops jararacussu in terms of toxin type, although some differences were observed. B. atrox showed a higher amount of the PIII class of metalloproteinases which correlates well with the observed intense hemorrhagic action of its toxin. Also, the PLA2 content was the second highest in this sample compared to the other three Bothrops transcriptomes. To our knowledge, this work is the first transcriptome analysis of an Amazonian rain forest pit viper and it will contribute to the body of knowledge regarding the gene diversity of the venom gland of members of the Bothrops genus. Moreover, our results can be used for future studies with other snake species from the Amazon region to investigate differences in gene patterns or phylogenetic relationships. PMID:19708221

Neiva, Márcia; Arraes, Fabricio B M; de Souza, Jonso Vieira; Rádis-Baptista, Gandhi; Prieto da Silva, Alvaro R B; Walter, Maria Emilia M T; Brigido, Marcelo de Macedo; Yamane, Tetsuo; López-Lozano, Jorge Luiz; Astolfi-Filho, Spartaco

2009-03-15

194

Effects of Schizolobium parahyba Extract on Experimental Bothrops Venom-Induced Acute Kidney Injury  

PubMed Central

Background Venom-induced acute kidney injury (AKI) is a frequent complication of Bothrops snakebite with relevant morbidity and mortality. The aim of this study was to assess the effects of Schizolobium parahyba (SP) extract, a natural medicine with presumed anti-Bothrops venom effects, in an experimental model of Bothrops jararaca venom (BV)-induced AKI. Methodology Groups of 8 to 10 rats received infusions of 0.9% saline (control, C), SP 2 mg/kg, BV 0.25 mg/kg and BV immediately followed by SP (treatment, T) in the doses already described. After the respective infusions, animals were assessed for their glomerular filtration rate (GFR, inulin clearance), renal blood flow (RBF, Doppler), blood pressure (BP, intra-arterial transducer), renal vascular resistance (RVR), urinary osmolality (UO, freezing point), urinary neutrophil gelatinase-associated lipocalin (NGAL, enzyme-linked immunosorbent assay [ELISA]), lactate dehydrogenase (LDH, kinetic method), hematocrit (Hct, microhematocrit), fibrinogen (Fi, Klauss modified) and blinded renal histology (acute tubular necrosis score). Principal Findings BV caused significant decreases in GFR, RBF, UO, HcT and Fi; significant increases in RVR, NGAL and LDH; and acute tubular necrosis. SP did not prevent these changes; instead, it caused a significant decrease in GFR when used alone. Conclusion SP administered simultaneously with BV, in an approximate 10?1 concentration, did not prevent BV-induced AKI, hemolysis and fibrinogen consumption. SP used alone caused a decrease in GFR. PMID:24551041

Martines, Monique Silva; Mendes, Mirian M.; Shimizu, Maria H. M.; Melo Rodrigues, Veridiana; de Castro, Isac; Filho, Sebastião R. Ferreira; Malheiros, Denise M. A. C.; Yu, Luis; Burdmann, Emmanuel A.

2014-01-01

195

DNA barcodes of Philippine accipitrids.  

PubMed

DNA barcoding is a molecular method that rapidly identifies an individual to a known taxon or its closest relative based on a 650-bp fragment of the cytochrome c oxidase subunit I (COI). In this study, DNA barcodes of members of the family Accipitridae, including Haliastur indus (brahminy kite), Haliaeetus leucogaster (white-bellied sea eagle), Ichthyophaga ichthyaetus (grey-headed fish eagle), Spilornis holospilus (crested serpent-eagle), Spizaetus philippensis (Philippine hawk-eagle), and Pithecophaga jefferyi (Philippine eagle), are reported for the first time. All individuals sampled are kept at the Philippine Eagle Center in Davao City, Philippines. Basic local alignment search tool results demonstrated that the COI sequences for these species were unique. The COI gene trees constructed using the maximum-likelihood and neighbour-joining (NJ) methods supported the monophyly of the booted eagles of the Aquilinae and the sea eagles of the Haliaeetinae but not the kites of the Milvinae. PMID:21429130

Ong, Perry S; Luczon, Adrian U; Quilang, Jonas P; Sumaya, Anna Mae T; Ibañez, Jayson C; Salvador, Dennis J; Fontanilla, Ian Kendrich C

2011-03-01

196

Alteration of Al-rich inclusions inside amoeboid olivine aggregates in the Allende meteorite  

NASA Technical Reports Server (NTRS)

The primary phases of Al-rich inclusions in amoeboid olivine aggregates have undergone alteration reactions with the solar nebular gas. The simplest interpretation of the present observations is that melilite was the first primary phase to disappear with falling temperature, and was replaced by grossular + anorthite + feldspathoids, followed by fassaite; spinel was the last phase to be altered. Thermodynamic calculations suggest that Na-rich phlogopite could have formed at about 470 K and chlorite at about 328 K at a water fugacity of 0.000001, which is that of a gas of solar composition in this temperature range. The olivine around Al-rich inclusions is not serpentized, indicating the cessation of gas-solid equilibrium above 274 K.

Hashimoto, Akihiko; Grossman, Lawrence

1987-01-01

197

Helminth fauna of a Japanese golden eagle, Aquila chrysaetos japonica.  

PubMed

A Japanese golden eagle, Aquila chrysaetos japonica, was found dead in Nagano Prefecture PB 399-8200, Japan, and subjected to necropsy. The necropsy revealed that the entire length of the intestine was filled with several masses of intestinal parasites. The recovered helminths were identified as one digenean trematode species, Neodiplostomum reflexum; two species of nematodes, Synhimantus sp. and larvae of Porrocaecum sp.; and a single species of Acanthocephala, Centrorhynchus sp. Digenea and acanthocephalans were found in massive numbers, obliterating the intestinal lumen, which suggests that the bird died as a result of the parasitic intestinal obstruction. The same type of helminths as those observed in this case was previously recorded in crested serpent eagles (Spilornis cheela perplexus) in Japan, but the present study emphasizes the presence of the four species in the Japanese golden eagle as a new host record. To the authors' knowledge, this is the first report of N. reflexum in Japan. PMID:23272374

El-Dakhly, Khaled; El-Nahass, El-Shaymaa; Sudo, Akiko; Uchida, Tadayoshi; Kakogawa, Masayoshi; Hirata, Akihiro; Sakai, Hiroki; Yanai, Tokuma

2012-12-01

198

The e-MERLIN Data Reduction Pipeline  

E-print Network

Written in Python and utilising ParselTongue to interface with the Astronomical Image Processing System (AIPS), the e-MERLIN data reduction pipeline is intended to automate the procedures required in processing and calibrating radio astronomy data from the e-MERLIN correlator. Driven by a plain text file of input parameters, the pipeline is modular and can be run in stages by the user, depending on requirements. The software includes options to load raw data, average in time and/or frequency, flag known sources of interference, flag more comprehensively with SERPent, carry out some or all of the calibration procedures including self-calibration), and image in either normal or wide-field mode. It also optionally produces a number of useful diagnostic plots at various stages so that the quality of the data can be assessed. The software is available for download from the e-MERLIN website or via Github.

Argo, Megan

2015-01-01

199

Comets in ancient India  

E-print Network

The Indo-aryans of ancient India observed stars and constellations for ascertaining auspicious times for sacrificial rites ordained by vedas. It is but natural that they would have recounted in the vedic texts about comets. In Rigveda ($\\sim $ 1700 - 1500 BC) and Atharvaveda ($\\sim $ 1150 BC), there are references to dhumaketus and ketus, which stand for comets in Sanskrit. Varahamihira in 550 AD and Ballala Sena ($\\sim $ 1100 - 1200 AD) have described a large number of comets recorded by ancient seers such as Parashara, Vriddha Garga, Narada, Garga, etc. In this article, I conjecture that an episode narrated in Mahabharata of a radiant king, Nahusha, ruling the heavens, and later turning into a serpent after he had kicked the seer Agastya (also the star Canopus), is a mythological retelling of a cometary event.

Gupta, Patrick Das

2014-01-01

200

e-MERLIN data reduction pipeline  

NASA Astrophysics Data System (ADS)

Written in Python and utilizing ParselTongue (ascl:1208.020) to interface with AIPS (ascl:9911.003), the e-MERLIN data reduction pipeline processes, calibrates and images data from the UK's radio interferometric array (Multi-Element Remote-Linked Interferometer Network). Driven by a plain text input file, the pipeline is modular and can be run in stages. The software includes options to load raw data, average in time and/or frequency, flag known sources of interference, flag more comprehensively with SERPent (ascl:1312.001), carry out some or all of the calibration procedures (including self-calibration), and image in either normal or wide-field mode. It also optionally produces a number of useful diagnostic plots at various stages so data quality can be assessed.

Argo, Megan

2014-07-01

201

An elastica arm scale.  

PubMed

The concept of a 'deformable arm scale' (completely different from a traditional rigid arm balance) is theoretically introduced and experimentally validated. The idea is not intuitive, but is the result of nonlinear equilibrium kinematics of rods inducing configurational forces, so that deflection of the arms becomes necessary for equilibrium, which would be impossible for a rigid system. In particular, the rigid arms of usual scales are replaced by a flexible elastic lamina, free to slide in a frictionless and inclined sliding sleeve, which can reach a unique equilibrium configuration when two vertical dead loads are applied. Prototypes designed to demonstrate the feasibility of the system show a high accuracy in the measurement of load within a certain range of use. Finally, we show that the presented results are strongly related to snaking of confined beams, with implications for locomotion of serpents, plumbing and smart oil drilling. PMID:25197248

Bosi, F; Misseroni, D; Dal Corso, F; Bigoni, D

2014-09-01

202

Spectroscopy of Moses Rock dike using remote sensing  

NASA Technical Reports Server (NTRS)

Zeiss IR-photographs, NS0001 (TM simulator) and airborne imaging spectrometer (AIS) data were obtained for the Moses Rock kimberlite dike in southern Utah to identify and characterize the distinctive mafic mineralogy of the dike as well as the surrounding sedimentary rocks. The Zeiss and NS001 images provide information on the regional setting and allow units of the dike to be distinguished from the sediments. The AIS data are narrow images obtained in 128 near-infrared channels and provide characterizing information on the surface composition through. Three distinct spectroscopic units were found which have been tentatively identified as serpentized olivine-bearing soils found in the dike and two types of gypsum bearing soils found in the surrounding sedimentary soils.

Mustard, J. F.; Pieters, C. M.

1985-01-01

203

[On gods, snakes and staffs--the emblem of the medical profession].  

PubMed

The commonly accepted emblems of the Medical Profession are the staff of the Greek god of medicine--Asklepios (or Asclepius], on which one serpent is entwined. Later, around the 16th century C.E., the wand of the herald of the Greek Gods, e.g., Hermes, on which two snakes are entwined and facing each other, became popular as the emblem of the medical profession. We elaborate on the history of the evolution of these emblems as symbols of medicine, including earlier influences from the times of the ancient Egyptians and Babylonians, which were followed by Judeo-Christian traditions and concepts. The relevance of the use of the wand of Hermes as an emblem of our profession is further discussed. PMID:25518083

Rabinerson, David; Salzer, Liat; Gabbay-Benziv, Rinnat

2014-10-01

204

Presence of a radioactive gas in archaeological excavations, determination and mitigation.  

PubMed

During recent archaeological discovery and excavation of a tunnel build approximately 2000 years ago by the Teotihuacans under the feathered serpent temple, in Mexico, abnormal radon concentrations up to 700 Bq m(-3) were measured at several excavation stages. The tunnel is at 15m below the earth surface with a vertical rectangular entrance of 4×4 m(2), a semi cylindrical shape of 3m in diameter, with a probable length of 100 m. This study supports the assumption that at the opening of the tunnel radon concentration was around 5500 Bq m(-3); however, although natural convection in the tunnel atmosphere naturally pups radon out, it build up to a maximum concentration of 2000 Bq m(-3). This paper presents the identification of the radon problem in this archaeological site, dose determination, and the mitigation actions that reduced the radon concentration down to 40 Bq m(-3) that ensure a negligible radon risk for archaeologist. PMID:23938077

Balcázar, M; Gómez, S; Peña, P; Zavala Arredondo, J; Gazzola, J; Villamares, A

2014-01-01

205

Snake Robots.com  

NSDL National Science Digital Library

One of the latest developments in robotics is flexible, snake-like machines that could be used for such activities as Martian landscape exploration because they are highly flexible, adaptable, and maneuverable into tight spaces and over relatively large obstacles. Snake Robots.com comes from robotics engineer Gavin Miller who developed his own "snakes" with inspiration from his work on physically-based computer animation at Alias Research, Inc. and Apple Computer, Inc. (Note: this private site is not affiliated with those corporations.) Visitors to Miller's site can see color videos, with audio, of his incredibly life-like serpents (.mpeg). Links to other snake robot sites are provided along with information about upcoming museum exhibitions and articles.

206

On the Asclepian spirit and the future of psychoanalysis.  

PubMed

The dynamics of the Asclepian myth are analyzed, and generic dynamics of the healing imperative are illustrated. The story teaches much about the early theories and practice of ancient medicine, and originated the healing symbol of the staff and serpent which appears on the emblem of the American Academy. The multi-modal therapeutic approach used at the Asclepia was often climaxed by dream incubation as a centerpiece of the treatment. Dreams from modern physicians in analysis will be introduced to show that while our practice has changed in external trappings, the underlying dynamics of ancient and modern healers reflect a common humanity. Modern therapists have reacquired the use of dreams and invented a new set of explanatory myths. Consideration of future developments leads to linking the "psychosomatic model" of antiquity with the psychopharmacological interventions which are now common-place in psychodynamic psychotherapy. The Asclepian emphasis on spirituality is also finding increasing recognition among psychoanalysts and other scientists. PMID:12064034

Whitehead, Clay C

2002-01-01

207

'Offensive' snakes: cultural beliefs and practices related to snakebites in a Brazilian rural settlement  

PubMed Central

This paper records the meaning of the term 'offense' and the folk knowledge related to local beliefs and practices of folk medicine that prevent and treat snake bites, as well as the implications for the conservation of snakes in the county of Pedra Branca, Bahia State, Brazil. The data was recorded from September to November 2006 by means of open-ended interviews performed with 74 individuals of both genders, whose ages ranged from 4 to 89 years old. The results show that the local terms biting, stinging and pricking are synonymous and used as equivalent to offending. All these terms mean to attack. A total of 23 types of 'snakes' were recorded, based on their local names. Four of them are Viperidae, which were considered the most dangerous to humans, besides causing more aversion and fear in the population. In general, local people have strong negative behavior towards snakes, killing them whenever possible. Until the antivenom was present and available, the locals used only charms, prayers and homemade remedies to treat or protect themselves and others from snake bites. Nowadays, people do not pay attention to these things because, basically, the antivenom is now easily obtained at regional hospitals. It is understood that the ethnozoological knowledge, customs and popular practices of the Pedra Branca inhabitants result in a valuable cultural resource which should be considered in every discussion regarding public health, sanitation and practices of traditional medicine, as well as in faunistic studies and conservation strategies for local biological diversity. PMID:20346120

2010-01-01

208

Snake venom dipeptidyl peptidase IV: taxonomic distribution and quantitative variation.  

PubMed

The present study examined the taxonomic distribution of dipeptidyl peptidase IV (DPP IV) activity in venoms of 59 ophidian taxa, representing seven subfamilies of the Families Elapidae and Viperidae. DPP IV activity is extremely variable at all taxonomic levels. It ranged from essentially none in laticaudine, hydrophiine, and some bungarine and elapine venoms, to 10.72 mumol 4-methoxy-beta-naphthylamine liberated per min per 200 mug venom, for Ophiophagus hannah. Intra- and interpopulational variation were examined among eight populations of prairie rattlesnakes (Crotalus viridis viridis), Great Basin rattlesnakes (Crotalus viridis lutosus) and southern Pacific rattlesnakes (Crotalus viridis helleri). Among these populations, the mean weighted range of variation was 4.9-fold, and even among litter mates of C. v. lutosus, DPP IV activity varied as much as 5.6-fold. The two most salient findings, the near ubiquity of DPP IV in snake venoms and its great quantitative variability, even among full siblings, are paradoxical. The widespread distribution of the enzyme suggests an important role in envenomation, while the variable activity levels suggest that DPP IV and by extension, other individual enzymatic constituents, may not be under much individual selective pressure. PMID:18440846

Aird, Steven D

2008-06-01

209

[Drug or plant substances which antagonize venoms or potentiate antivenins].  

PubMed

Dendroaspis jamesoni (Elapidae) and Echis oceliatus (Viperidae) are responsible for most of severe evenomation in Cameroon. Toxicity of venoms of these two species has been measured using mice according to the method of Spearman & Kàrber. The effect on experimental envenomation of various drugs (atropine, promethazine, neostigmine, hydrocortisone, pentosane sulfuric polyester, heparin, tranexamic acid and aminocaproic acid) and plant extracts (Schumanniophyton magnificum, Bidens pilosa, Securidaca longepedunculata and Garcinia lucida) has been observed associated or not with the antivenom lpser Afrique (SAV). The venom of D. jamesoni contains neurotoxins agonizing and antagonising acetylcholine. The toxicity of the venom did not depend on the route of injection. Atropine, promethazine, neostigmine and hydrocortisone protected animals against a venom dose up to 2 LD50. Moreover, atropine and promethazine potentiated the SAV. Similar results have been obtained with extracts from S. magnificum and B. pilosa. The venom of E. ocellatus induces haemorrhage and necrosis. The toxicity increased by 3-fold when the venom was injected through intravenous or intraperitoneal route, compared to intramuscular route. Pentosane sulfuric polyester and tranexamic acid protected mice against doses up to 3 LD50. Pentosane sulfuric polyester, hydrocortisone, heparin and aminocaproic acid increased the SAV protective titre by 50%. However, tried plant extracts weakly antagonised the venom and did not potentiate the SAV. PMID:9479470

Chippaux, J P; Rakotonirina, V S; Rakotonirina, A; Dzikouk, G

1997-01-01

210

cDNA cloning of the two subunits of phospholipase A2 inhibitor PLIgamma from blood plasma of the Chinese mamushi, Agkistrodon blomhoffii siniticus.  

PubMed

Three phospholipase A2 (PLA2) inhibitors (PLI) have been purified from the blood plasma of the Chinese mamushi, Agkistrodon blomhoffii siniticus; 1 of these, PLIgamma, contains 2 homologous subunits, PLIgamma-A and PLIgamma-B. The cDNAs encoding these 2 subunits of PLIgamma were isolated from a liver cDNA library by using fragments from polymerase chain reaction amplifications as probes and sequenced. The respective nucleotide sequences encoded 19-residue signal sequences, followed by 181-residue proteins. The calculated molecular masses were 20123 and 20150 Da for the PLIgamma-A and PLIgamma-B subunits, respectively; and PLIgamma-A included a N-linked carbohydrate site at Asn-157. The sequences of these subunits contained 2 internal repeats of disulfide-bonding pattern characteristic to those of urokinase-type plasminogen activator receptor and members of the Ly-6 superfamily. A phylogenetic analysis comparing the amino acid sequences of PLIgamma-A and PLIgamma-B with those for other snakes revealed that the gene duplication leading to these 2 subunits occurred before the divergence of Viperidae and Elapidae. PMID:10791922

Okumura, K; Inoue, S; Ohkura, N; Ikeda, K; Hayashi, K

1999-07-01

211

Small serum protein-1 changes the susceptibility of an apoptosis-inducing metalloproteinase HV1 to a metalloproteinase inhibitor in habu snake (Trimeresurus flavoviridis)  

PubMed Central

Viperidae snakes containing various venomous proteins also have several anti-toxic proteins in their sera. However, the physiological function of serum protein has been elucidated incompletely. Small serum protein (SSP)-1 is a major component of the SSPs isolated from the serum of a Japanese viper, the habu snake (Trimeresurus flavoviridis). It exists in the blood as a binary complex with habu serum factor (HSF), a snake venom metalloproteinase inhibitor. Affinity chromatography of the venom on an SSP-1-immobilized column identified HV1, an apoptosis-inducing metalloproteinase, as the target protein of SSP-1. Biacore measurements revealed that SSP-1 was bound to HV1 with a dissociation constant of 8.2 × 10?8 M. However, SSP-1 did not inhibit the peptidase activity of HV1. Although HSF alone showed no inhibitory activity or binding affinity to HV1, the SSP-1–HSF binary complex bound to HV1 formed a ternary complex that non-competitively inhibited the peptidase activity of HV1 with a inhibition constant of 5.1 ± 1.3 × 10?9 M. The SSP-1–HSF complex also effectively suppressed the apoptosis of vascular endothelial cells and caspase 3 activation induced by HV1. Thus, SSP-1 is a unique protein that non-covalently attaches to HV1 and changes its susceptibility to HSF. PMID:23100271

Shioi, Narumi; Ogawa, Eiki; Mizukami, Yuki; Abe, Shuhei; Hayashi, Rieko; Terada, Shigeyuki

2013-01-01

212

Molecular evolution of snake toxins: is the functional diversity of snake toxins associated with a mechanism of accelerated evolution?  

PubMed

Recent studies revealed that animal toxins with unrelated biological functions often possess a similar architecture. To tentatively understand the evolutionary mechanisms that may govern this principle of functional prodigality associated with a structural economy, two complementary approaches were considered. One of them consisted of investigating the rates of mutations that occur in cDNAs and/or genes that encode a variety of toxins with the same fold. This approach was largely adopted with phospholipases A2 from Viperidae and to a lesser extent with three-fingered toxins from Elapidae and Hydrophiidae. Another approach consisted of investigating how a given fold can accommodate distinct functional topographies. Thus, a number of topologies by which three-fingered toxins exert distinct functions were investigated either by making chemical modifications and/or mutational analyses or by studying the three-dimensional structure of toxin-target complexes. This review shows that, although the two approaches are different, they commonly indicate that most if not all the surface of a snake toxin fold undergoes natural engineering, which may be associated with an accelerated rate of evolution. The biochemical process by which this phenomenon occurs remains unknown. PMID:9427847

Ohno, M; Ménez, R; Ogawa, T; Danse, J M; Shimohigashi, Y; Fromen, C; Ducancel, F; Zinn-Justin, S; Le Du, M H; Boulain, J C; Tamiya, T; Ménez, A

1998-01-01

213

Venomous adversaries: a reference to snake identification, field safety, and bite-victim first aid for disaster-response personnel deploying into the hurricane-prone regions of North America.  

PubMed

Each hurricane season, emergency-preparedness deployment teams including but not limited to the Office of Force Readiness and Deployment of the US Public Health Service, Federal Emergency Management Agency, Deployment Medical Assistance Teams, Veterinary Medical Assistance Teams, and the US Army and Air Force National Guard are at risk for deploying into hurricane-stricken areas that harbor indigenous hazards, including those posed by venomous snakes. North America is home to 2 distinct families of venomous snakes: 1) Viperidae, which includes the rattlesnakes, copperheads, and cottonmouths; and 2) Elapidae, in which the only native species are the coral snakes. Although some of these snakes are easily identified, some are not, and many rank among the most feared and misunderstood animals. This article specifically addresses all the native species of venomous snakes that inhabit the hurricane-prone regions of North America and is intended to serve as a reference to snake identification, basic field safety procedures, and the currently recommended first-aid measures for snakebite casualties. PMID:17219788

Wozniak, Edward J; Wisser, John; Schwartz, Michael

2006-01-01

214

Scales microstructure of snakes from the Egyptian area.  

PubMed

The morphology of many organisms seems to be related to the environments in which they live. Many snakes are so similar in their morphological patterns that it becomes quite difficult to distinguish any adaptive divergence that may have occurred. Many authors have suggested that the microstructure of the reptile's scales has important functional value. Herein, we investigate variations on the micromorphology of the external surface of dorsal scales on the head, the mid-body region (trunk), and the tail of Rhomphotyphlops braminus (Typhlopidae), Eryx jaculus (Boidae), Psammophis sibilans (Colubridae), Naja haje (Elapidae) and Echis carinatus (Viperidae). The specimens were metallized and analyzed by scanning electron microscopy. All species displayed unique dorsal scale surface microstructures of the investigated regions. The microstructural pattern of the scales of head, trunk, and tail differs in different species of these snakes. In conclusion, we detected ecomorphologic relationships between extant dorsal scale microstructures and snake microhabitat, enabling us to hypothesize that environmental pressures have significant influences not only on these animals' macrostructure, but also on its microstructure as well. PMID:23106563

Allam, Ahmed A; Abo-Eleneen, Rasha E

2012-11-01

215

Purification and cloning of cysteine-rich proteins from Trimeresurus jerdonii and Naja atra venoms.  

PubMed

Three 26 kDa proteins, named as TJ-CRVP, NA-CRVP1 and NA-CRVP2, were isolated from the venoms of Trimeresurus jerdonii and Naja atra, respectively. The N-terminal sequences of TJ-CRVP and NA-CRVPs were determined. These components were devoid of the enzymatic activities tested, such as phospholipase A(2), arginine esterase, proteolysis, L-amino acid oxidase, 5'nucleotidase, acetylcholinesterase. Furthermore, these three components did not have the following biological activities: coagulant and anticoagulant activities, lethal activity, myotoxicity, hemorrhagic activity, platelet aggregation and platelet aggregation-inhibiting activities. These proteins are named as cysteine-rich venom protein (CRVP) because their sequences showed high level of similarity with mammalian cysteine-rich secretory protein (CRISP) family. Recently, some CRISP-like proteins were also isolated from several different snake venoms, including Agkistrodon blomhoffi, Trimeresurus flavoviridis, Lanticauda semifascita and king cobra. We presumed that CRVP might be a common component in snake venoms. Of particular interest, phylogenetic analysis and sequence alignment showed that NA-CRVP1 and ophanin, both from elapid snakes, share higher similarity with CRVPs from Viperidae snakes. PMID:14529736

Jin, Yang; Lu, Qiumin; Zhou, Xingding; Zhu, Shaowen; Li, Rui; Wang, Wanyu; Xiong, Yuliang

2003-10-01

216

Ten years of snakebites in Iran.  

PubMed

Many species of venomous snakes are found in Iran. The most medically important species which are responsible for the most snakebite incidents in Iran belong to the Viperidae family, including Vipera lebetina, Echis carinatus, Pseudocerastes persicus, Vipera albicornuta and the Elapidae family, especially Naja naja oxiana. At least one kind of venomous snake is found in each of the 31 provinces, and many provinces have more than one venomous species. As a result, snakebite is a considerable health hazard in Iran, especially in the rural area of south and south-west of Iran. A retrospective, descriptive study of snakebite in Iran during 2002-2011 was carried out in order based on data collected from medical records of bite victims admitted to hospitals and health centers. From 2002 to 2011, 53,787 cases of snake bites were reported by medical centers in Iran. The annual incidence of snake bites in 100,000 of population varied from 4.5 to 9.1 during this decade and the number of recorded deaths were about 67 cases. The highest rate of snakebite was found in provinces of south and southwest of Iran. We suggest that people, especially in the rural areas, need to be trained and educated about venomous snakes, their hazards, prevention of bite and the importance of early hospital referral and treatment of victims. Also adequate antivenins as the main life saving medicine should be made available based on the recorded numbers of victims in each area of the country. PMID:25193748

Dehghani, Rouhullah; Fathi, Behrooz; Shahi, Morteza Panjeh; Jazayeri, Mehrdad

2014-11-01

217

Snakebite management in Iran: Devising a protocol  

PubMed Central

Background: Snakebite in Iran has been a health concern. However, management of snakebite is not standardized and varies from center to center. This study is aimed at devising an evidence-based comprehensive protocol for snakebite management in Iran, to reduce unnecessary variations in practice. Materials and Methods: A narrative search in electronic databases was performed. Fifty peer-reviewed articles, guidelines, and textbooks were reviewed and practical details were extracted. Our currently used protocol in the Mashhad Toxicology Center was supplemented with this information. Consequently an improved wide-range protocol was developed. The protocol was then discussed and amended within a focus group comprised of medical toxicologists and internal medicine specialists. The amended version was finally discussed with expert physicians specialized in different areas of medicine, to be optimized by supplementing other specific considerations. Results: During a one-year process, the protocol was finalized. The final version of the protocol, which was designed in six steps, comprised of three components: A schematic algorithm, a severity grading scale, and instructions for supportive and adjunctive treatments. The algorithm pertains to both Viperidae and Elapidae snakebite envenomations and consists of a planned course of action and dosing of antivenom, based on the severity of the envenomation. Conclusion: Snakebite envenomation is a clinical toxicologic emergency, which needs to be treated in a timely and organized manner. Hence, a multi-aspect protocol was designed to improve the clinical outcomes, reduce unnecessary administration of antivenom, and help physicians make more proper clinical judgments. PMID:24778670

Monzavi, Seyed Mostafa; Dadpour, Bita; Afshari, Reza

2014-01-01

218

Antimicrobial proteins from snake venoms: direct bacterial damage and activation of innate immunity against Staphylococcus aureus skin infection.  

PubMed

The innate immune system is the first line of defense against microbial diseases. Antimicrobial proteins produced by snake venoms have recently attracted significant attention due to their relevance to bacterial infection and potential development into new therapeutic agents. Staphylococcus aureus is one of the major human pathogens causing a variety of infections involving pneumonia, toxic shock syndrome, and skin lesions. With the recent emergence of methicillin (MRSA) and vancomycin (VRSA) resistance, S. aureus infection is a serious clinical problem that will have a grave socio-economic impact in the near future. Although S. aureus susceptibility to innate antimicrobial peptides has been reported recently, the protective effect of snake venom phospholipase A? (svPLA?) proteins on the skin from S. aureus infection has been understudied. This review details the protective function of svPLA?s derived from venoms against skin infections caused by S. aureus. We have demonstrated in vivo that local application of svPLA? provides complete clearance of S. aureus within 2 weeks after treatment compared to fusidic acid ointment (FAO). In vitro experiments also demonstrate that svPLA? proteins have inhibitory (bacteriostatic) and killing (bactericidal) effects on S. aureus in a dose-dependant manner. The mechanism of bacterial membrane damage and perturbation was clearly evidenced by electron microscopic studies. In summary, svPLA?s from Viperidae and Elapidae snakes are novel molecules that can activate important mechanisms of innate immunity in animals to endow them with protection against skin infection caused by S. aureus. PMID:22050758

Samy, R P; Stiles, B G; Gopalakrishnakone, P; Chow, V T K

2011-01-01

219

Complete mitochondrial DNA sequences of six snakes: phylogenetic relationships and molecular evolution of genomic features.  

PubMed

Complete mitochondrial DNA (mtDNA) sequences were determined for representative species from six snake families: the acrochordid little file snake, the bold boa constrictor, the cylindrophiid red pipe snake, the viperid himehabu, the pythonid ball python, and the xenopeltid sunbeam snake. Thirteen protein-coding genes, 22 tRNA genes, 2 rRNA genes, and 2 control regions were identified in these mtDNAs. Duplication of the control region and translocation of the tRNALeu gene were two notable features of the snake mtDNAs. The duplicate control regions had nearly identical nucleotide sequences within species but they were divergent among species, suggesting concerted sequence evolution of the two control regions. In addition, the duplicate control regions appear to have facilitated an interchange of some flanking tRNA genes in the viperid lineage. Phylogenetic analyses were conducted using a large number of sites (9570 sites in total) derived from the complete mtDNA sequences. Our data strongly suggested a new phylogenetic relationship among the major families of snakes: ((((Viperidae, Colubridae), Acrochordidae), (((Pythonidae, Xenopeltidae), Cylindrophiidae), Boidae)), Leptotyphlopidae). This conclusion was distinct from a widely accepted view based on morphological characters in denying the sister-group relationship of boids and pythonids, as well as the basal divergence of nonmacrostomatan cylindrophiids. These results imply the significance to reconstruct the snake phylogeny with ample molecular data, such as those from complete mtDNA sequences. PMID:16007493

Dong, Songyu; Kumazawa, Yoshinori

2005-07-01

220

Correlation between annual activity patterns of venomous snakes and rural people in the Niger Delta, southern Nigeria  

PubMed Central

Background Venomous snakes are among the most serious health hazards for rural people in tropical regions of the world. Herein we compare the monthly activity patterns of eight venomous snake species (Elapidae and Viperidae) with those of rural people in the Niger Delta area of southern Nigeria, in order to identify the periods of highest potential risk for persons, and the human group actually at greater risk of snakebite. Results We documented that above-ground activity of all venomous snakes peaked in the wet season, and that high snake activity and high human activity were most highly correlated between April and August. In addition, we documented that women and teenagers were at relatively higher risk of encountering a venomous snake than adult males, despite they are less often in the field than men. Conclusions Our results suggest that future programs devoted to mitigate the social and health effects of snakebites in the Niger Delta region should involve especially women and teenagers, with ad-hoc education projects if appropriate. We urge that international organizations working on social and health problems in the developing world, such as IRD, DFID, UNDP, should provide advice through specific programs targeted at especially these categories which have been highlighted in comparatively potential higher threat from snakebites than adult men. PMID:23849681

2013-01-01

221

Cysteine-rich venom proteins from the snakes of Viperinae subfamily - molecular cloning and phylogenetic relationship.  

PubMed

Cysteine-rich proteins found in animal venoms (CRISP-Vs) are members of a large family of cysteine-rich secretory proteins (CRISPs). CRISP-Vs acting on different ion channels were found in venoms or mRNA (cDNA) encoding CRISP-Vs were cloned from snakes of three main families (Elapidae, Colubridae and Viperidae). About thirty snake CRISP-Vs were sequenced so far, however no complete sequence for CRISP-V from Viperinae subfamily was reported. We have cloned and sequenced for the first time cDNAs encoding CRISP-Vs from Vipera nikolskii and Vipera berus vipers (Viperinae). The deduced mature CRISP-V amino acid sequences consist of 220 amino acid residues. Phylogenetic analysis showed that viper proteins are closely related to those of Crotalinae snakes. The presence of CRISP-V in the V. berus venom was revealed using a combination of gel-filtration chromatography, electrophoresis and MALDI mass spectrometry. The finding of the putative channel blocker in viper venom may indicate its action on prey nervous system. PMID:19041663

Ramazanova, Anna S; Starkov, Vladislav G; Osipov, Alexey V; Ziganshin, Rustam H; Filkin, Sergey Yu; Tsetlin, Victor I; Utkin, Yuri N

2009-01-01

222

[Vipera berus bite-epidemiology, clinical symptoms and review of treatment methods].  

PubMed

Adder (Vipera berus), which belongs to the family Viperidae, is the only venomous snake occurs on Polish territory. Components of the venom exhibit proteolytic, fibrinolytic, and anticoagulant activity, and activity of phospholipase A2. They damage proteins, including proteins of the blood vessels walls, leukocytes and erythrocyte membranes. The clinical course of poisoning depends on the dose of venom, concomitant diseases, site of the bite, physical activity after the bite, individual susceptibility, age, weight, kind of bite, secondary infection, and the management. All patients bitten by an adder should be admitted to the hospital for observations. In cases of mild poisoning treatment procedure is limited to symptomatic treatment in the form of administration of analgesics and antiemetic drugs. Some bites are called as "dry bites" where no venom is injected into the body. It is advisable to follow the directions for use of antitoxin by reason of the risk of anaphylactic shock and serum sickness. It should be administered against general poisoning or in the case of massive or rapidly spreading oedema. PMID:20976951

Zajkowska, Joanna; Garkowski, Adam; Pancewicz, S?awomir

2010-01-01

223

Epithelium specific ETS transcription factor, ESE-3, of Protobothrops flavoviridis snake venom gland transactivates the promoters of venom phospholipase A2 isozyme genes.  

PubMed

Protobothrops flavoviridis (habu) (Crotalinae, Viperidae) is a Japanese venomous snake, and its venom contains the enzymes with a variety of physiological activities. The phospholipases A2 (PLA2s) are the major components and exert various toxic effects. They are expressed abundantly in the venom gland. It is thought that the venom gland-specific transcription factors play a key role for activation of PLA2 genes specifically expressed in the venom gland. Thus, the full-length cDNA library for P. flavoviridis venom gland after milking of the venom was made to explore the transcription factors therein. As a result, three cDNAs encoding epithelium-specific ETS transcription factors (ESE)-1, -2, and -3 were obtained. Among them, ESE-3 was specifically expressed in the venom gland and activated the proximal promoters of venom PLA2 genes, which are possibly regarded as the representatives of the venom gland-specific protein genes in P. flavoviridis. Interestingly, the binding specificity of ESE-3 to the ETS binding motif located near TATA box is well correlated with transcriptional activities for the venom PLA2 genes. This is the first report that venom gland-specific transcription factor could actually activate the promoters of the venom protein genes. PMID:25449102

Nakamura, Hitomi; Murakami, Tatsuo; Hattori, Shosaku; Sakaki, Yoshiyuki; Ohkuri, Takatoshi; Chijiwa, Takahito; Ohno, Motonori; Oda-Ueda, Naoko

2014-12-15

224

Molecular Cloning, Characterization, and Chromosome Mapping of Reptilian Estrogen Receptors  

PubMed Central

In many vertebrates, steroid hormones are essential for ovarian differentiation during a critical developmental stage as well as promoting the growth and differentiation of the adult female reproductive system. Although studies have been extensively conducted in mammals and a few fish, amphibians, and bird species, the molecular mechanisms of sex steroid hormone (estrogens) action have been poorly examined in reptiles. Here, we evaluate hormone receptor and ligand interactions in two species of snake, the Okinawa habu (Protobothrops flavoviridis, Viperidae) and the Japanese four-striped rat snake (Elaphe quadrivirgata, Colubridae) after the isolation of cDNAs encoding estrogen receptor ? (ESR1) and estrogen receptor ? (ESR2). Using a transient transfection assay with mammalian cells, the transcriptional activity of reptilian (Okinawa habu, Japanese four-striped rat snake, American alligator, and Florida red-belly freshwater turtle) ESR1 and ESR2 was examined. All ESR proteins displayed estrogen-dependent activation of transcription via an estrogen-response element-containing promoter; however, the responsiveness to various estrogens was different. Further, we determined the chromosomal locations of the snake steroid hormone receptor genes. ESR1 and ESR2 genes were localized to the short and long arms of chromosome 1, respectively, whereas androgen receptor was localized to a pair of microchromosomes in the two snake species examined. These data provide basic tools that allow future studies examining receptor-ligand interactions and steroid endocrinology in snakes and also expands our knowledge of sex steroid hormone receptor evolution. PMID:20926589

Katsu, Yoshinao; Matsubara, Kazumi; Kohno, Satomi; Matsuda, Yoichi; Toriba, Michihisa; Oka, Kaori; Guillette, Louis J.; Ohta, Yasuhiko; Iguchi, Taisen

2010-01-01

225

NMR structure of bitistatin - a missing piece in the evolutionary pathway of snake venom disintegrins.  

PubMed

Extant disintegrins, as found in the venoms of Viperidae and Crotalidae snakes (vipers and rattlesnakes, represent a family of polypeptides that block the function of ?1 and ?3 integrin receptors, both potently and with a high degree of selectivity. This toxin family owes its origin to the neofunctionalization of the extracellular region of an ADAM (a disintegrin and metalloprotease) molecule recruited into the snake venom gland proteome in the Jurassic. The evolutionary structural diversification of the disintegrin scaffold, from the ancestral long disintegrins to the more recently evolved medium-sized, dimeric and short disintegrins, involved the stepwise loss of pairs of class-specific disulfide linkages and the processing of the N-terminal region. NMR and crystal structures of medium-sized, dimeric and short disintegrins have been solved. However, the structure of a long disintegrin remained unknown. The present study reports the NMR solution structures of two disulfide bond conformers of the long disintegrin bitistatin from the African puff adder Bitis arietans. The findings provide insight into how a structural domain of the extracellular region of an ADAM molecule, recruited into and selectively expressed in the snake venom gland proteome as a PIII metalloprotease in the Jurassic, has subsequently been tranformed into a family of integrin receptor antagonists. PMID:25363287

Carbajo, Rodrigo J; Sanz, Libia; Perez, Alicia; Calvete, Juan J

2015-01-01

226

A Complex-Geometry Validation Experiment for Advanced Neutron Transport Codes  

SciTech Connect

The Idaho National Laboratory (INL) has initiated a focused effort to upgrade legacy computational reactor physics software tools and protocols used for support of core fuel management and experiment management in the Advanced Test Reactor (ATR) and its companion critical facility (ATRC) at the INL.. This will be accomplished through the introduction of modern high-fidelity computational software and protocols, with appropriate new Verification and Validation (V&V) protocols, over the next 12-18 months. Stochastic and deterministic transport theory based reactor physics codes and nuclear data packages that support this effort include MCNP5[1], SCALE/KENO6[2], HELIOS[3], SCALE/NEWT[2], and ATTILA[4]. Furthermore, a capability for sensitivity analysis and uncertainty quantification based on the TSUNAMI[5] system has also been implemented. Finally, we are also evaluating the Serpent[6] and MC21[7] codes, as additional verification tools in the near term as well as for possible applications to full three-dimensional Monte Carlo based fuel management modeling in the longer term. On the experimental side, several new benchmark-quality code validation measurements based on neutron activation spectrometry have been conducted using the ATRC. Results for the first four experiments, focused on neutron spectrum measurements within the Northwest Large In-Pile Tube (NW LIPT) and in the core fuel elements surrounding the NW LIPT and the diametrically opposite Southeast IPT have been reported [8,9]. A fifth, very recent, experiment focused on detailed measurements of the element-to-element core power distribution is summarized here and examples of the use of the measured data for validation of corresponding MCNP5, HELIOS, NEWT, and Serpent computational models using modern least-square adjustment methods are provided.

David W. Nigg; Anthony W. LaPorta; Joseph W. Nielsen; James Parry; Mark D. DeHart; Samuel E. Bays; William F. Skerjanc

2013-11-01

227

Dyke swarm emplacement in the Ethiopian Large Igneous Province: not only a matter of stress  

NASA Astrophysics Data System (ADS)

In the Tana-Belaya area, western Ethiopia, field data and satellite imagery reveal the existence of two dyke swarms, the NE-SW Serpent-God dyke swarm, and the NW-SE Dinder dyke swarm. Both swarms are thought to have the same age, 30 Ma, and are likely to have contributed to feeding the traps. After a description of the swarms, this paper examines their relationships with the basement structures. The two dyke swarms follow major lithospheric weakness zones. The Serpent-God dyke swarm follows the Pan-African Tulu Dimtu ductile shear zone, and the Dinder dyke swarm follows a large NW-SE-trending Precambrian fracture zone already reactivated during the Mesozoic and Cenozoic as the northern boundary of the Blue Nile Rift. Because the dyke swarms are adjacent but their orientation differs, the stress trajectory patterns during their emplacement were spatially variable at local scale. Therefore, rather than plate-boundary processes, the origin of stress is thought to be primarily related to the Ethiopian plume. Postulating (in the absence of more data relating to the magma chambers that fed the traps) that dyke orientation is the result of an axisymmetric stress field, the location of the stress source can be placed close to Lake Tana, which is the centre of the Ethiopian broad negative regional Bouguer anomaly. The dykes in the Tana-Belaya area provide the first clues to the orientation of the stress field that prevailed in the early history of the Ethiopian mantle plume, and to some of the factors that guided the distribution of the trap feeders.

Mège, Daniel; Korme, Tesfaye

2004-05-01

228

Drosophila E-Cadherin Functions in Hematopoietic Progenitors to Maintain Multipotency and Block Differentiation  

PubMed Central

A fundamental question in stem cell biology concerns the regulatory strategies that control the choice between multipotency and differentiation. Drosophila blood progenitors or prohemocytes exhibit key stem cell characteristics, including multipotency, quiescence, and niche dependence. As a result, studies of Drosophila hematopoiesis have provided important insights into the molecular mechanisms that control these processes. Here, we show that E-cadherin is an important regulator of prohemocyte fate choice, maintaining prohemocyte multipotency and blocking differentiation. These functions are reminiscent of the role of E-cadherin in mammalian embryonic stem cells. We also show that mis-expression of E-cadherin in differentiating hemocytes disrupts the boundary between these cells and undifferentiated prohemocytes. Additionally, upregulation of E-cadherin in differentiating hemocytes increases the number of intermediate cell types expressing the prohemocyte marker, Patched. Furthermore, our studies indicate that the Drosophila GATA transcriptional co-factor, U-shaped, is required for E-cadherin expression. Consequently, E-cadherin is a downstream target of U-shaped in the maintenance of prohemocyte multipotency. In contrast, we showed that forced expression of the U-shaped GATA-binding partner, Serpent, repressed E-cadherin expression and promoted lamellocyte differentiation. Thus, U-shaped may maintain E-cadherin expression by blocking the inhibitory activity of Serpent. Collectively, these observations suggest that GATA:FOG complex formation regulates E-cadherin levels and, thereby, the choice between multipotency and differentiation. The work presented in this report further defines the molecular basis of prohemocyte cell fate choice, which will provide important insights into the mechanisms that govern stem cell biology. PMID:24040319

Gao, Hongjuan; Wu, Xiaorong; Fossett, Nancy

2013-01-01

229

A novel peptide from the ACEI/BPP-CNP precursor in the venom of Crotalus durissus collilineatus.  

PubMed

In crotaline venoms, angiotensin-converting enzyme inhibitors [ACEIs, also known as bradykinin potentiating peptides (BPPs)], are products of a gene coding for an ACEI/BPP-C-type natriuretic peptide (CNP) precursor. In the genes from Bothrops jararaca and Gloydius blomhoffii, ACEI/BPP sequences are repeated. Sequencing of a cDNA clone from venom glands of Crotalus durissus collilineatus showed that two ACEIs/BPPs are located together at the N-terminus, but without repeats. An additional sequence for CNP was unexpectedly found at the C-terminus. Homologous genes for the ACEI/BPP-CNP precursor suggest that most crotaline venoms contain both ACEIs/BPPs and CNP. The sequence of ACEIs/BPPs is separated from the CNP sequence by a long spacer sequence. Previously, there was no evidence that this spacer actually coded any expressed peptides. Aird and Kaiser (1986, unpublished) previously isolated and sequenced a peptide of 11 residues (TPPAGPDVGPR) from Crotalus viridis viridis venom. In the present study, analysis of the cDNA clone from C. d. collilineatus revealed a nearly identical sequence in the ACEI/BPP-CNP spacer. Fractionation of the crude venom by reverse phase HPLC (C(18)), and analysis of the fractions by mass spectrometry (MS) indicated a component of 1020.5 Da. Amino acid sequencing by MS/MS confirmed that C. d. collilineatus venom contains the peptide TPPAGPDGGPR. Its high proline content and paired proline residues are typical of venom hypotensive peptides, although it lacks the usual N-terminal pyroglutamate. It has no demonstrable hypotensive activity when injected intravenously in rats; however, its occurrence in the venoms of dissimilar species suggests that its presence is not accidental. Evidence suggests that these novel toxins probably activate anaphylatoxin C3a receptors. PMID:16979945

Higuchi, Shigesada; Murayama, Nobuhiro; Saguchi, Ken-ichi; Ohi, Hiroaki; Fujita, Yoshiaki; da Silva, Nelson Jorge; de Siqueira, Rodrigo José Bezerra; Lahlou, Saad; Aird, Steven D

2006-10-01

230

Structure of saxthrombin, a thrombin-like enzyme from Gloydius saxatilis  

PubMed Central

Snake-venom thrombin-like enzymes (SVTLEs) are serine proteases that are widely distributed in snakes from the Crotalinae subfamily of the Viperidae. In contrast to other snake-venom serine proteases, they have a biochemical activity similar to that of thrombin and play an important role in the process of blood coagulation. However, SVTLEs cannot activate factor VIII, which is essential in blood-clot stabilization. Consequently, blood clots produced by SVTLEs are not stable and are cleared rapidly. This characteristic makes SVTLEs attractive as potential candidates for antithrombotic therapy. Saxthrombin, an SVTLE from Gloydius saxatilis, was purified and crystallized to obtain a high-quality crystal, from which data were acquired to 1.43?Å resolution. Preliminary X-ray diffraction analysis showed that the crystal belonged to space group C2, with unit-cell parameters a = 94.2, b = 52.2, c = 50.1?Å, ? = 96.7°. The crystal structure was determined by molecular replacement and the final R factor was 18.69%; the R free was 20.01%. This is the first report of a crystal structure of an SVTLE. Saxthrombin belongs to the typical ?/?-hydrolase fold of serine proteases. Its structure was compared with those of thrombin and other snake-venom serine proteases. The observed differences in the amino-acid composition of the loops surrounding the active site appear to contribute to different surface-charge distributions and thus alter the shape of the active-site cleft, which may explain the differences in substrate affinity. PMID:21821882

Huang, Kai; Zhao, Wei; Gao, Yongxiang; Wei, Wenqing; Teng, Maikun; Niu, Liwen

2011-01-01

231

[Use of a body condition index (BCI) for the study of the reproduction in snakes].  

PubMed

A body condition index (BCI = actual body mass/optimal theoritical body mass of the studied animal) was estimated in females of 3 species of snake. From dissections of 88 Vipera aspis and 18 Coluber viridiflavus, strong relationships between body reserves (such as mass of fat bodies and liver) and BCI were found. Furthermore, BCI explained most of the variance in the mass of the fat bodies and in the mass of the liver; however BCI and body length together increased the percentage of variation explained. Thus, a satisfactory estimation of body reserves in relation to body length is possible in living snakes. We have studied reproductive parameters (clutch size and litter size) in Vipera aspis (Viperidae) and Elaphe longissima (Colubridae) during a 3 year period. In the two species positive relationships between maternal body length and number of offspring were found. At the beginning of vitellogenesis, litter size is related to the BCI level in V. aspis but not in E. longissima. In both species, BCI must exceed a threshold value for reproduction to take place. However this threshold value is much lower in E. longissima (0.55) than in V. aspis (0.70). This indicates that in the latter species, large body reserves are necessary for the induction of vitellogenesis. In E. longissima, maternal body length is an important determinant of reproductive success, body reserves playing a minor role. In contrast, in female V. aspis the reproductive success is related to BCI and to a lesser extent to body length.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7987689

Bonnet, X; Naulleau, G

1994-01-01

232

Molecular Evolution of Vertebrate Neurotrophins: Co-Option of the Highly Conserved Nerve Growth Factor Gene into the Advanced Snake Venom Arsenalf  

PubMed Central

Neurotrophins are a diverse class of structurally related proteins, essential for neuronal development, survival, plasticity and regeneration. They are characterized by major family members, such as the nerve growth factors (NGF), brain-derived neurotrophic factors (BDNF) and neurotrophin-3 (NT-3), which have been demonstrated here to lack coding sequence variations and follow the regime of negative selection, highlighting their extremely important conserved role in vertebrate homeostasis. However, in stark contrast, venom NGF secreted as part of the chemical arsenal of the venomous advanced snake family Elapidae (and to a lesser extent Viperidae) have characteristics consistent with the typical accelerated molecular evolution of venom components. This includes a rapid rate of diversification under the significant influence of positive-selection, with the majority of positively-selected sites found in the secreted ?-polypeptide chain (74%) and on the molecular surface of the protein (92%), while the core structural and functional residues remain highly constrained. Such focal mutagenesis generates active residues on the toxin molecular surface, which are capable of interacting with novel biological targets in prey to induce a myriad of pharmacological effects. We propose that caenophidian NGFs could participate in prey-envenoming by causing a massive release of chemical mediators from mast cells to mount inflammatory reactions and increase vascular permeability, thereby aiding the spread of other toxins and/or by acting as proapoptotic factors. Despite their presence in reptilian venom having been known for over 60 years, this is the first evidence that venom-secreted NGF follows the molecular evolutionary pattern of other venom components, and thus likely participates in prey-envenomation. PMID:24312363

Sunagar, Kartik; Fry, Bryan Grieg; Jackson, Timothy N. W.; Casewell, Nicholas R.; Undheim, Eivind A. B.; Vidal, Nicolas; Ali, Syed A.; King, Glenn F.; Vasudevan, Karthikeyan; Vasconcelos, Vitor; Antunes, Agostinho

2013-01-01

233

Molecular evolution of vertebrate neurotrophins: co-option of the highly conserved nerve growth factor gene into the advanced snake venom arsenalf.  

PubMed

Neurotrophins are a diverse class of structurally related proteins, essential for neuronal development, survival, plasticity and regeneration. They are characterized by major family members, such as the nerve growth factors (NGF), brain-derived neurotrophic factors (BDNF) and neurotrophin-3 (NT-3), which have been demonstrated here to lack coding sequence variations and follow the regime of negative selection, highlighting their extremely important conserved role in vertebrate homeostasis. However, in stark contrast, venom NGF secreted as part of the chemical arsenal of the venomous advanced snake family Elapidae (and to a lesser extent Viperidae) have characteristics consistent with the typical accelerated molecular evolution of venom components. This includes a rapid rate of diversification under the significant influence of positive-selection, with the majority of positively-selected sites found in the secreted ?-polypeptide chain (74%) and on the molecular surface of the protein (92%), while the core structural and functional residues remain highly constrained. Such focal mutagenesis generates active residues on the toxin molecular surface, which are capable of interacting with novel biological targets in prey to induce a myriad of pharmacological effects. We propose that caenophidian NGFs could participate in prey-envenoming by causing a massive release of chemical mediators from mast cells to mount inflammatory reactions and increase vascular permeability, thereby aiding the spread of other toxins and/or by acting as proapoptotic factors. Despite their presence in reptilian venom having been known for over 60 years, this is the first evidence that venom-secreted NGF follows the molecular evolutionary pattern of other venom components, and thus likely participates in prey-envenomation. PMID:24312363

Sunagar, Kartik; Fry, Bryan Grieg; Jackson, Timothy N W; Casewell, Nicholas R; Undheim, Eivind A B; Vidal, Nicolas; Ali, Syed A; King, Glenn F; Vasudevan, Karthikeyan; Vasconcelos, Vitor; Antunes, Agostinho

2013-01-01

234

In vitro and in vivo genotoxic evaluation of Bothrops moojeni snake venom.  

PubMed

Abstract Context: Bothrops moojeni Hoge (Viperidae) venom is a complex mixture of compounds with therapeutic potential that has been included in the research and development of new drugs. Along with the biological activity, the pharmaceutical applicability of this venom depends on its toxicological profile. Objective: This study evaluates the cytotoxicity and genotoxicity of the Bothrops moojeni venom (BMV). Material and methods: The in vitro cytotoxicity and genotoxicity of a pooled sample of BMV was assessed by the MTT and Comet assay, respectively. Genotoxicity was also evaluated in vivo through the micronucleus assay. Results: BMV displayed a 50% cytotoxic concentration (CC50) on Vero cells of 4.09?µg/mL. Vero cells treated with 4?µg/mL for 90?min and 6?h presented significant (p?

Novak Zobiole, Nathalia; Caon, Thiago; Wildgrube Bertol, Jéssica; Alves de Souza Pereira, Cintia; Mary Okubo, Brunna; Moreno, Susana Elisa; Tramontini Gomes de Sousa Cardozo, Francielle

2014-11-28

235

Stable isotope tracer reveals that viviparous snakes transport amino acids to offspring during gestation.  

PubMed

Viviparity and placentation have evolved from oviparity over 100 times in squamate reptiles (lizards and snakes). The independent origins of placentation have resulted in a variety of placental morphologies in different taxa, ranging from simple apposition of fetal and maternal tissues to endotheliochorial implantation that is homoplasious with mammalian placentation. Because the eggs of oviparous squamates transport gases and water from the environment and calcium from the eggshell, the placentae of viviparous squamates are thought to have initially evolved to accomplish these functions from within the maternal oviduct. Species with complex placentae have also been shown to rely substantially, or even primarily, on placental transport of organic nutrients for embryonic nutrition. However, it is unclear whether species with only simple placentae are also capable of transporting organic nutrients to offspring. Among viviparous squamates, all of the snakes that have been studied thus far have been shown to have simple placentae. However, most studies of snake placentation are limited to a single lineage, the North American Natricinae. We tested the abilities of four species of viviparous snakes - Agkistrodon contortrix (Viperidae), Boa constrictor (Boidae), Nerodia sipedon (Colubridae: Natricinae) and Thamnophis sirtalis (Colubridae: Natricinae) - to transport diet-derived amino acids to offspring during gestation. We fed [(15)N]leucine to pregnant snakes, and compared offspring (15)N content with that of unlabeled controls. Labeled females allocated significantly more (15)N to offspring than did controls, but (15)N allocation did not differ among species. Our results indicate that viviparous snakes are capable of transporting diet-derived amino acids to their offspring during gestation, possibly via placentation. PMID:22323198

Van Dyke, James U; Beaupre, Steven J

2012-03-01

236

Structural and Functional Studies of a Bothropic Myotoxin Complexed to Rosmarinic Acid: New Insights into Lys49-PLA2 Inhibition  

PubMed Central

Snakebite envenoming is an important public health problem in many tropical and subtropical countries, and is considered a neglected tropical disease by the World Health Organization. Most severe cases are inflicted by species of the families Elapidae and Viperidae, and lead to a number of systemic and local effects in the victim. One of the main problems regarding viperidic accidents is prominent local tissue damage whose pathogenesis is complex and involves the combined actions of a variety of venom components. Phospholipases A2 (PLA2s) are the most abundant muscle-damaging components of these venoms. Herein, we report functional and structural studies of PrTX-I, a Lys49-PLA2 from Bothops pirajai snake venom, and the influence of rosmarinic acid (RA) upon this toxin's activities. RA is a known active component of some plant extracts and has been reported as presenting anti-myotoxic properties related to bothopic envenomation. The myotoxic activity of Lys49-PLA2s is well established in the literature and although no in vivo neurotoxicity has been observed among these toxins, in vitro neuromuscular blockade has been reported for some of these proteins. Our in vitro studies show that RA drastically reduces both the muscle damage and the neuromuscular blockade exerted by PrTX-I on mice neuromuscular preparations (by ?80% and ?90%, respectively). These results support the hypothesis that the two effects are closely related and lead us to suggest that they are consequences of the muscle membrane-destabilizing activity of the Lys49-PLA2. Although the C-terminal region of these proteins has been reported to comprise the myotoxic site, we demonstrate by X-ray crystallographic studies that RA interacts with PrTX-I in a different region. Consequently, a new mode of Lys49-PLA2 inhibition is proposed. Comparison of our results with others in the literature suggests possible new ways to inhibit bothropic snake venom myotoxins and improve serum therapy. PMID:22205953

dos Santos, Juliana I.; Cardoso, Fábio F.; Soares, Andreimar M.; dal Pai Silva, Maeli; Gallacci, Márcia; Fontes, Marcos R. M.

2011-01-01

237

The complete mitochondrial genome of a gecko and the phylogeneticposition of the Middle Eastern teratoscincus keyserlingii  

SciTech Connect

Sqamate reptiles are traditionally divided into six groups: Iguania, Anguimorpha, Scincomorpha, Gekkota (these four are lizards), Serpentes (snakes), and Amphisbaenia (the so-called worm lizards). Currently there are complete mitochondrial genomes from two representatives of the Iguania (Janke et al., 2001; Kumazawa, 2004), three from the Anguimorpha (Kumazawa, 2004; Kumazawa and Endo, 2004), two from the Scincomorpha (Kumazawa and Nishida, 1999; Kumazawa, 2004), two from Serpentes (Kumazawa et al., 1998; Kumazawa, 2004) and 12 from Amphisbaenia (Macey et al., 2004). The only traditional group of Squamata from which a complete mitochondrial genome has not been sequenced is the Gekkota. Here we report the complete mitochondrial genome of Teratoscincus keyserlingii, a Middle Eastern representative of the Gekkota. The gekkonid lizard genus Teratoscincus is distributed throughout the deserts of central and southwest Asia as shown in figure 1, with five species currently recognized (Macey et al. 1997a, 1999b). Included in this figure are the positions of mountain ranges discussed in the text; see also figure 1 in Macey et al. (1999b). Two species, T. bedriagai and T. microlepis, are restricted to Southwest Asia south of the Kopet Dagh and Hindu Kush in Iran, Afghanistan, and Pakistan (Anderson, 1999). Two species are found in the deserts of western China and Mongolia, with T. przewalskii occurring in the Taklimakan and lowland Gobi deserts, and T. roborowskii restricted to the Turpan Depression. The fifth species, T. scincus, is sometimes considered to be restricted to the Caspian Basin in Kazakhstan, Kyrgyzistan, Tadjikistan, Turkmenistan and Uzbekistan. Alternatively, Teratoscincus populations in Southwest Asia, primarily on the Iranian Plateau, situated directly north of the Arabian Plate, are sometimes considered to be a subspecies of T. scincus or, otherwise, to constitute a sixth species, T. keyserlingii. Macey et al. (1999b) assessed the phylogenetic relationships of four Teratoscincus species with mitochondrial DNA sequences from a {approx}1800 base-pair segment spanning from nad1 to cox1. Phylogenetic analysis places T. microlepis in a basal position to a clade containing T. scincus, T. przewalskii and T. roborowskii, with the later two as sister taxa. This phylogenetic arrangement suggests that tectonic plate movements in Southwest Asia and western China due to the Indian and Arabian collisions caused speciation among Teratoscincus species. No molecular phylogenetic study has included the putative species T. keyserlingii.

Macey, J. Robert; Fong, Jonathan J.; Kuehl, Jennifer V.; Shafiei,Soheila; Ananjeva, Natalia B.; Papenfuss, Theodore J.; Boore, Jeffrey L.

2005-04-22

238

Do Cross-circle Designs, the Mayan World Tree, Chitto Tustenuggee's, and Miami's Tequesta, Sites have Analogs in Brazil as they have in Peru, Europe, and Africa?  

NASA Astrophysics Data System (ADS)

Florida's Miami Tequesta site conveys information about potential tornadoes, hurricanes, and even earthquakes. It is visually analogous to cross-circle designs, like other equivalent sites we have located, as in Maine, New Hampshire, in Medicine Wheels, and elsewhere. We focus on the detectable effects of time-and-place dependent electromagnetic signals. Non-technologic societies, and individuals, still find and use them, even today, especially in places like Cuzco, Peru. Modes of detection involve senses, such as sensitive, observant eyesight, and electromagnetically induced nerve signals interpreted as tinnitus, as traditionally indicated by ``Kokopelli's'' flute-playing, ``pins and needles,'' or even odor sensations. Recorded events show that youthful children are sometimes involved, as by Pacal's Classic-Mayan-era son, who became Kan Balum, Serpent Jaguar. Our intent is to check whether similar signals can be technologically identified in Brazil and New England. Site information investigated by us seems to be driven by the electromagnetic field. Enigmatic Brazilian locations should be technologically investigated with site correlations to other possible analogs, such as Florida's Chitto Tustenuggee site at Miramar. To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2007.NES07.C2.6

Ataide, Jade; Mc Leod, Roger; Mc Leod, David

2007-04-01

239

Art exhibit focuses on African astronomy  

NASA Astrophysics Data System (ADS)

Connections between Africans and astronomy are the focus of a new exhibition in the National Museum of African Art in Washington, D. C. “African Cosmos: Stellar Arts,” which includes artwork, cultural items, and scientific displays from ancient to contemporary times, is the first major exhibit “that brings together arts and science focused on Africa's contribution to keen observations of the heavens over time,” curator Christine Mullen Kreamer said at a 20 June news briefing. Among the exhibit's nearly 100 objects are an ancient Egyptian mummy board that includes a representation of the sky goddess Nut, sculptures by the Dogon people of Mali depicting figures in relation to the cosmos, a video that uses data from two square degrees of the Hubble Space Telescope Cosmic Evolution Survey, and a nearly floor-to-ceiling “Rainbow Serpent” constructed of plastic containers by Benin artist Hazoume. An untitled acrylic painting (Figure 1) by South African Gavin Jantjes evokes a myth of the Khoi San people of southern Africa, as it portrays a girl throwing evening fire embers into the night sky, where they remained as the Milky Way.

Showstack, Randy

2012-07-01

240

Carbon Isotope Measurements of Experimentally-Derived Hydrothermal Mineral-Catalyzed Organic Products by Pyrolysis-Isotope Ratio Mass Spectrometry  

NASA Technical Reports Server (NTRS)

We report results of experiments to measure the C isotope composition of mineral catalyzed organic compounds derived from high temperature and high pressure synthesis. These experiments make use of an innovative pyrolysis technique designed to extract and measure C isotopes. To date, our experiments have focused on the pyrolysis and C isotope ratio measurements of low-molecular weight intermediary hydrocarbons (organic acids and alcohols) and serve as a proof of concept for making C and H isotope measurements on more complicated mixtures of solid-phase hydrocarbons and intermediary products produced during high temperature and high pressure synthesis on mineral-catalyzed surfaces. The impetus for this work stems from recently reported observations of methane detected within the Martian atmosphere [1-4], coupled with evidence showing extensive water-rock interaction during Martian history [5-7]. Methane production on Mars could be the result of synthesis by mineral surface-catalyzed reduction of CO2 and/or CO by Fischer-Tropsch Type (FTT) reactions during serpentization reactions [8,9]. Others have conducted experimental studies to show that FTT reactions are plausible mechanisms for low-molecular weight hydrocarbon formation in hydrothermal systems at mid-ocean ridges [10-12]. Further, recent experiments by Fu et al. [13] focus on examining detailed C isotope measurements of hydrocarbons produced by surface-catalyzed mineral reactions. Work described in this paper details the experimental techniques used to measure intermediary organic reaction products (alcohols and organic acids).

Socki, Richard A.; Fu, Qi; Niles, Paul B.

2011-01-01

241

Neutronics and Fuel Performance Evaluation of Accident Tolerant Fuel under Normal Operation Conditions  

SciTech Connect

This report details the analysis of neutronics and fuel performance analysis for enhanced accident tolerance fuel, with Monte Carlo reactor physics code Serpent and INL’s fuel performance code BISON, respectively. The purpose is to evaluate two of the most promising candidate materials, FeCrAl and Silicon Carbide (SiC), as the fuel cladding under normal operating conditions. Substantial neutron penalty is identified when FeCrAl is used as monolithic cladding for current oxide fuel. From the reactor physics standpoint, application of the FeCrAl alloy as coating layer on surface of zircaloy cladding is possible without increasing fuel enrichment. Meanwhile, SiC brings extra reactivity and the neutron penalty is of no concern. Application of either FeCrAl or SiC could be favorable from the fuel performance standpoint. Detailed comparison between monolithic cladding and hybrid cladding (cladding + coating) is discussed. Hybrid cladding is more practical based on the economics evaluation during the transition from current UO2/zircaloy to Accident Tolerant Fuel (ATF) system. However, a few issues remain to be resolved, such as the creep behavior of FeCrAl, coating spallation, inter diffusion with zirconium, etc. For SiC, its high thermal conductivity, excellent creep resistance, low thermal neutron absorption cross section, irradiation stability (minimal swelling) make it an excellent candidate materials for future nuclear fuel/cladding system.

Xu Wu; Piyush Sabharwall; Jason Hales

2014-07-01

242

The phylogenetic position and taxonomic status of the Rainbow Tree Snake Gonyophis margaritatus (Peters, 1871) (Squamata: Colubridae) .  

PubMed

Molecular phylogenies have provided strong evidence for clarifying the taxonomy of groups with ambiguous morphological traits, thus avoiding potentially misleading conclusions based on evolutionary convergence of these traits. For snakes, established molecular databases along with new sequences from rare species allows us to estimate phylogenies, to clarify the phylogenetic relationships and test the monophyly of most taxonomic groups. Using one mitochondrial gene and five nuclear loci, we evaluate the taxonomic status of a rare Southeast Asian serpent, the Rainbow Tree Snake Gonyophis margaritatus (Squamata: Colubridae) by inferring a molecular phylogeny of 101 snake species. Both maximum likelihood and time- calibrated Bayesian inference phylogenies demonstrate that G. margaritatus is sister to Rhadinophis prasinus, previously considered to be part of a radiation of Old World ratsnakes. This group is in turn sister to a group containing Rhadinophis frenatus and Rhynchophis boulengeri with the entire clade originating in the mid-Miocene (~16 Ma) in Southeast Asia. This group is sister to the genus Gonyosoma and together originated in the early Miocene (~20 Ma). We discuss three potential solutions towards eliminating polyphyly of the genus Rhadinophis, but recommend using the genus name Gonyosoma for all species within this clade, which currently contains all of the species within the genera Gonyosoma, Gonyophis, Rhadinophis, and Rhynchophis.  PMID:25543651

Chen, Xin; Mckelvy, Alexander D; Grismer, L Lee; Matsui, Masafumi; Nishikawa, Kanto; Burbrink, Frank T

2014-01-01

243

The story of the condom  

PubMed Central

Condoms have been a subject of curiosity throughout history. The idea of safer sex has been explored in ancient and modern history, and has been used to prevent venereal diseases. We conducted a historical and medical review of condoms using primary and secondary sources as well as using the RSM library and the internet. These resources show that the first use of a condom was that of King Minos of Crete. Pasiphae, his wife, employed a goat's bladder in the vagina so that King Minos would not be able to harm her as his semen was said to contain “scorpions and serpents” that killed his mistresses. To Egyptians, condom-like glans caps were dyed in different colours to distinguish between different classes of people and to protect themselves against bilharzia. The Ancient Romans used the bladders of animals to protect the woman; they were worn not to prevent pregnancy but to prevent contraction of venereal diseases. Charles Goodyear, the inventor, utilized vulcanization, the process of transforming rubber into malleable structures, to produce latex condoms. The greater use of condoms all over the world in the 20th and 21st centuries has been related to HIV. This account of the use of condoms demonstrates how a primitive idea turned into an object that is used globally with a forecast estimated at 18 billion condoms to be used in 2015 alone. PMID:23671357

Khan, Fahd; Mukhtar, Saheel; Dickinson, Ian K.; Sriprasad, Seshadri

2013-01-01

244

Evaluation of the adequacy of using few-group lattice-homogenized properties for the diffusion analysis of the super critical water reactor  

SciTech Connect

Two issues may affect the accuracy of computed core reactivities and flux/power distributions for the Super Critical Water Reactor (SCWR) core with traditional core-analysis code RFSP: one is the two-energy-group neutron-diffusion theory; the other is the generation of lattice-homogenized properties with the lattice code based on the single-lattice-cell model without considering the effects of the environment. These two issues are not SCWR specific; however their effect may be more significant for SCWR. It has been illustrated that the lattice-homogenized properties calculated with the single-lattice-cell model is not sufficiently accurate for heterogeneous core configurations such as ACR-1000 checkerboard-voiding and core-reflector interface when adjacent channels experience significant spectrum interaction. To evaluate the adequacy of using two-group neutron-diffusion theory with single-lattice-based lattice properties for the analysis of the SCWR core, a 2-D SCWR benchmark problem was setup with the reference solution provided by the continuous-energy Monte-Carlo code SERPENT. The assessment shows that the traditional two-group neutron-diffusion theory with the single-lattice-cell- based lattice properties is not sufficient to capture either the spectral change or the environment effect for the SCWR core. The solution of the eight-group neutron-diffusion equation with the multicell- based lattice properties is considered appropriate for the analysis of the d SCWR core. (authors)

Shen, W. [Candu Energy Inc., 2285 Speakman Dr., Mississauga, ON L5B 1K (Canada)

2012-07-01

245

226Ra and other radionuclides in water, vegetation, and tissues of beavers (Castor canadensis) from a watershed containing U tailings near Elliot Lake, Canada.  

PubMed

Radionuclide levels were measured in tissues, gut contents, diet items, and water at site of capture, of adult beavers from the Serpent River drainage basin which contains U tailings at Elliot Lake, Ontario, and from nearby control sites. Levels of (226)Ra in beaver bone, muscle and kidney were highest in animals from locations close to U tailings; liver levels did not vary by site. Environmental (226)Ra levels were within ranges previously reported at these or similar locations elsewhere; levels in beaver gut contents reflected levels in diet items. Concentration ratios exceeded unity only between some vegetation items and beaver bone at the Elliot Lake site and were less than 0.19 between vegetation and other tissues. In two beavers with tissue levels of (226)Ra higher than other sampled, neither (232)Th nor (230)Th were detected in bone, muscle or liver tissues. U-238 was measurable in bone, muscle and liver, (228)Th in bone, (210)Po bone, muscle and liver; and (210)Pb was measurable only in bone. Estimated yearly intakes of radionuclides by people eating beavers were calculated to be below current allowable levels set by the Canadian regulatory authorities. PMID:15092150

Clulow, F V; Mirka, M A; Davé, N K; Lim, T P

1991-01-01

246

Maine's MOLLOCKET and METALLAK: Adherents of God's Secret Spirit Signal, SSS, Applied Physicists of the EMF/Manitou, Doctors, Reincarnationists, "Potlachers," Confidants of the Powerful, and, they Did Own the Land.  

NASA Astrophysics Data System (ADS)

Northeastern ``Indians,'' reputed to ``make the weather,'' actually, from youth, observed earth phenomena, including SSS. These are subtle and barely detectable visual artifacts of the electromagnetic field, special information that led/leads to their spiritual belief in reincarnation, which came from the EMF/SSS communication, backward and forward, (up to) seven generations. It commands communal, democratic, ``potlatch'' redistribution of accumulated wealth, Mother Earth's bounty, from their land, gifted by ``The Great Spirit,'' Manitou, Peru's Ñari Huallac, ``Serpent God.'' Genetics established the non-Asian origins of 1/3 of North American Indians. Linguistics indicates a major impact westwards to us. MILLInocket is ``Adherent of God (Spirit-signal) monk Cathar.'' Katahdin, with a shared root, has Manitou. After 1820, Gov. E. Lincoln and at least one US senator went westward to MetALLAk; his biography is by a Rumford, ME Knight of Pythias. Why? MOLLOCKET frequently asserted ownership of western Maine. ``Great Council Fires,'' religious ``Law Things,'' were at Merrymeeting Bay in pre-Colonial times. ``Medicine men/priests'' often participated as their applied scientist-statesmen. To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2007.NES07.C2.1

Andrade, Jennifer; Ferreira, Nadja; Mc Leod, Roger D.

2007-04-01

247

Genome-Wide Transcription Analysis of Clinal Genetic Variation in Drosophila  

PubMed Central

Clinal variation in quantitative traits is widespread, but its genetic basis awaits identification. Drosophila melanogaster shows adaptive, clinal variation in traits such as body size along latitudinal gradients on multiple continents. To investigate genome wide transcription differentiation between North and South that might contribute to the clinal phenotypic variation, we compared RNA expression patterns during development of D. melanogaster from tropical northern and temperate southern populations using whole genome tiling arrays. We found that genes that were differentially expressed between the cline ends were generally associated with metabolism and growth, and experimental alteration of expression of a sample of them generally resulted in altered body size in the predicted direction, sometimes significantly so. We further identified the serpent (srp) transcription factor binding sites to be enriched near genes up-regulated in expression in the south. Analysis of clinal populations revealed a significant cline in the expression level of srp. Experimental over-expression of srp increased body size, as predicted from its clinal expression pattern, suggesting that it may be involved in regulating adaptive clinal variation in Drosophila. This study identified a handful of genes that contributed to clinal phenotypic variation through altered gene expression level, yet misexpression of individual gene led to modest body size change. PMID:22514645

Chen, Ying; Lee, Siu F.; Blanc, Eric; Reuter, Caroline; Wertheim, Bregje; Martinez-Diaz, Pedro; Hoffmann, Ary A.; Partridge, Linda

2012-01-01

248

Did Indians of the Americas Preserve Linguistic Place-names Like Willimantic, CT, Indicating Some Islamic Interactions and Applied Physics Use, Before Columbus?  

NASA Astrophysics Data System (ADS)

Modern Peruvians document: ``Ñari Huallac is the name of the town in the north of Peru (Piura) where our families come from. The words Ñari Huallac mean Serpent God, [editorial emphasis by underlining script is added], and are some of the few words which remain from the ancient Tallan civilization.'' Tallan seems related to The God, Allah, of Islam, as are Alaska, Allagash, Illinois, Willimantic, CT, and, in Maine, Metallak, Mollocket and Millinocket, Allahpatah, of Florida, and Allegheny of Pennsylvania. With this significance lies the partially concealed evidence that all three monotheistic faiths, during the times indicated by the language, understood there was a fundamental connection between The God, and what we would call today the electromagnetic field, EMF, of Mother Earth. Metallak: Doctor (at) The God (Spirit-signal, EMF), an ecclesiastical title, like Willimantic, The God Spirit-signal (where there is a) doctor. Alaska: The God Jesus Christ Spirit-signal (EMF). Millinocket: Adherent of The God monk Cathar, provides a reference date of about 1250 A.D. Illinois: The God Spirit-signal (EMF-detecting) monk. Mollocket asserted ownership of western Maine, until 1816. What did she know of importance from her war-hostage days in Boston?

Crory, Erica; Mc Leod, Roger D.

2007-10-01

249

Combining Total Monte Carlo and Benchmarks for Nuclear Data Uncertainty Propagation on a Lead Fast Reactor's Safety Parameters  

NASA Astrophysics Data System (ADS)

Analyses are carried out to assess the impact of nuclear data uncertainties on keff for the European Lead Cooled Training Reactor (ELECTRA) using the Total Monte Carlo method. A large number of 239Pu random ENDF-formatted libraries generated using the TALYS based system were processed into ACE format with NJOY-99.336 code and used as input into the Serpent Monte Carlo neutron transport code to obtain distribution in keff. The mean of the keff distribution obtained was compared with the major nuclear data libraries, JEFF-3.1.1, ENDF/B-VII.1 and JENDL-4.0. A method is proposed for the selection of benchmarks for specific applications using the Total Monte Carlo approach. Finally, an accept/reject criterion was investigated based on ?2 values obtained using the 239Pu Jezebel criticality benchmark. It was observed that nuclear data uncertainties in keff were reduced considerably from 748 to 443 pcm by applying a more rigid acceptance criteria for accepting random files.

Alhassan, E.; Sjöstrand, H.; Duan, J.; Gustavsson, C.; Koning, A. J.; Pomp, S.; Rochman, D.; Österlund, M.

2014-04-01

250

Preparation of nuclear libraries with deterministic and stochastic methods for LWR reflectors  

SciTech Connect

The explicit reflector methodology is used in the system of codes CASMO-5 / SIMULATE-3 to include the reflector around the active core into the computational region and avoid adopting any ad-hoc or experimental albedo coefficients as boundary conditions. However, to complete the core calculation, a set of cross sections and discontinuity factors is needed for the reflector nodes and the accuracy of these nuclear parameters influences the final results, in particular along the peripheral regions of the core. In this paper the explicit reflector methodology of CASMO-5 is adopted to evaluate the few-group cross sections and discontinuity factors of the different reflector cases, based on the design of Generation II and III LWR reactors. In addition, in the perspective of using Monte-Carlo codes as a complementary option for lattice calculations of reflector configurations, the stochastic SERPENT code is also included as part of this benchmark. With the latter, the impact of applying 2-D reflector models with homogenized materials instead of explicit representation of the real geometrical structures is moreover evaluated and shown to be limited. (authors)

Canepa, S.; Hursin, M.; Ferroukhi, H.; Pautz, A. [Paul Scherrer Institut PSI, 5232, Villigen PSI (Switzerland)

2013-07-01

251

Large Cretaceous sphenodontian from Patagonia provides insight into lepidosaur evolution in Gondwana.  

PubMed

Sphenodontian reptiles successfully radiated during Triassic and Jurassic times, but were driven almost to extinction during the Cretaceous period. The sparse Early Cretaceous record of sphenodontians has been interpreted as reflecting the decline of the group in favour of lizards, their suspected ecological successors. However, recent discoveries in Late Cretaceous beds in Patagonia partially modify this interpretation. Numerous skeletons of a new sphenodontian, Priosphenodon avelasi gen. et sp. nov., were collected from a single locality in the Cenomanian-Turonian Candeleros Formation, where it is more abundant than any other tetrapod group recorded in the quarry (for example, Crocodyliformes, Serpentes, Dinosauria and Mammalia). Adult specimens of Priosphenodon reached one metre in length, larger than any previously known terrestrial sphenodontian. Here we propose, using available evidence, that sphenodontians were not a minor component of the Cretaceous terrestrial ecosystems of South America, and that their ecological replacement by squamates was delayed until the early Tertiary. The new discovery helps to bridge the considerable gap in the fossil record (around 120 million years) that separates the Early Cretaceous sphenodontians from their living relatives (Sphenodon). PMID:14534584

Apesteguía, Sebastián; Novas, Fernando E

2003-10-01

252

Birmingham Conservatoire Historical Instrument Collection  

NSDL National Science Digital Library

If you have ever had a penchant to check out an ancient flageolet or a historic bass horn, this delightful online collection from the Birmingham Conservatoire Historical Instrument Collection is just the ticket. The project was developed by Professor George Caird and his colleagues at Birmingham City University, and funding for the project was provided by Arts & Humanities Research Council. From the homepage, visitors can browse the catalog of instruments by name or by maker, look over a host of images, and listen to some excellent audio samples of the instruments. The instruments are divided into categories that include "Trombones", "Plucked Strings", "Keyboards", and "Serpents, Ophicleides and Bass Horns". Each instrument is accompanied by information about its place of origin, its maker, its overall size, and numerous photographs. Moving on, the "Audio Resources" area is quite a pip, and visitors can listen to expert musicians playing everything from an 1836 piccolo to a folded coach horn making its way through Mozart's Post Horn Serenade.

253

Snakes antibodies.  

PubMed

Immunoglobulins are basic molecules of the immune system of vertebrates. In previous studies we described the immunoglobulins found in two squamata reptiles, Anolis carolinensis and Eublepharis macularius. Snakes are squamata reptiles too but they have undergone an extreme evolutionary process. We therefore wanted to know how these changes affected their immunoglobulin coding genes. To perform this analysis we studied five snake transcriptomes and two genome draft sequences. Sequences coding for immunoglobulin M (IgM), immunoglobulin D (IgD) and two classes of immunoglobulin Y (IgY - named IgYa and IgYb-) were found in all of them. Moreover, the Thamnophis elegans transcriptome and Python molurus genome draft sequences showed a third class of IgY, the IgYc, whose constant region only presents three domains and lacks the CH2. All data suggest that the IgYb is the evolutionary origin of this IgYc. An exhaustive search of the light chains were carried out, being lambda the only light chain found in snakes. The results provide a clear picture of the immunoglobulins present in the suborder Serpentes. PMID:22426516

Gambón-Deza, Francisco; Sánchez-Espinel, Christian; Mirete-Bachiller, Serafín; Magadán-Mompó, Susana

2012-09-01

254

Carbon Isotope Systematics in Mineral-Catalyzed Hydrothermal Organic Synthesis Processes at High Temperature and Pressures  

NASA Technical Reports Server (NTRS)

Observation of methane in the Martian atmosphere has been reported by different detection techniques. Reduction of CO2 and/or CO during serpentization by mineral surface catalyzed Fischer-Tropsch Type (FTT) synthesis may be one possible process responsible for methane generation on Mars. With the evidence a recent study has discovered for serpentinization in deeply buried carbon rich sediments, and more showing extensive water-rock interaction in Martian history, it seems likely that abiotic methane generation via serpentinization reactions may have been common on Mars. Experiments involving mineral-catalyzed hydrothermal organic synthesis processes were conducted at 750 C and 5.5 Kbars. Alkanes, alcohols and carboxylic acids were identified as organic compounds. No "isotopic reversal" of delta C-13 values was observed for alkanes or carboxylic acids, suggesting a different reaction pathway than polymerization. Alcohols were proposed as intermediaries formed on mineral surfaces at experimental conditions. Carbon isotope data were used in this study to unravel the reaction pathways of abiotic formation of organic compounds in hydrothermal systems at high temperatures and pressures. They are instrumental in constraining the origin and evolution history of organic compounds on Mars and other planets.

Fu, Qi; Socki, R. A.; Niles, Paul B.

2011-01-01

255

Peptidomics of Three Bothrops Snake Venoms: Insights Into the Molecular Diversification of Proteomes and Peptidomes*  

PubMed Central

Snake venom proteomes/peptidomes are highly complex and maintenance of their integrity within the gland lumen is crucial for the expression of toxin activities. There has been considerable progress in the field of venom proteomics, however, peptidomics does not progress as fast, because of the lack of comprehensive venom sequence databases for analysis of MS data. Therefore, in many cases venom peptides have to be sequenced manually by MS/MS analysis or Edman degradation. This is critical for rare snake species, as is the case of Bothrops cotiara (BC) and B. fonsecai (BF), which are regarded as near threatened with extinction. In this study we conducted a comprehensive analysis of the venom peptidomes of BC, BF, and B. jararaca (BJ) using a combination of solid-phase extraction and reversed-phase HPLC to fractionate the peptides, followed by nano-liquid chromatography-tandem MS (LC-MS/MS) or direct infusion electrospray ionization-(ESI)-MS/MS or MALDI-MS/MS analyses. We detected marked differences in the venom peptidomes and identified peptides ranging from 7 to 39 residues in length by de novo sequencing. Forty-four unique sequences were manually identified, out of which 30 are new peptides, including 17 bradykinin-potentiating peptides, three poly-histidine-poly-glycine peptides and interestingly, 10 l-amino acid oxidase fragments. Some of the new bradykinin-potentiating peptides display significant bradykinin potentiating activity. Automated database search revealed fragments from several toxins in the peptidomes, mainly from l-amino acid oxidase, and allowed the determination of the peptide bond specificity of proteinases and amino acid occurrences for the P4-P4? sites. We also demonstrate that the venom lyophilization/resolubilization process greatly increases the complexity of the peptidome because of the imbalance caused to the venom proteome and the consequent activity of proteinases on venom components. The use of proteinase inhibitors clearly showed different outcomes in the peptidome characterization and suggested that degradomic-peptidomic analysis of snake venoms is highly sensitive to the conditions of sampling procedures. PMID:22869554

Tashima, Alexandre K.; Zelanis, André; Kitano, Eduardo S.; Ianzer, Danielle; Melo, Robson L.; Rioli, Vanessa; Sant'anna, Sávio S.; Schenberg, Ana C. G.; Camargo, Antônio C. M.; Serrano, Solange M. T.

2012-01-01

256

A new structurally atypical bradykinin-potentiating peptide isolated from Crotalus durissus cascavella venom (South American rattlesnake).  

PubMed

Venom glands of some snakes synthesize bradykinin-potentiating peptides (BPP's) which increase bradykinin-induced hypotensive effect and decrease angiotensin I vasopressor effect by angiotensin-converting enzyme (ACE) inhibition. The present study shows a new BPP (BPP-Cdc) isolated from Crotalus durissus cascavella venom: Pro-Asn-Leu-Pro-Asn-Tyr-Leu-Gly-Ile-Pro-Pro. Although BPP-Cdc presents the classical sequence IPP in the C-terminus, it has a completely atypical N-terminal sequence, which shows very low homology with all other BPPs isolated to date. The pharmacological effects of BPP-Cdc were compared to BBP9a from Bothrops jararaca and captopril. BPP-Cdc (1 ?M) significantly increased BK-induced contractions (BK; 1 ?M) on the guinea pig ileum by 267.8% and decreased angiotensin I-induced contractions (AngI; 10 nM) by 62.4% and these effects were not significantly different from those of BPP9a (1 ?M) or captopril (200 nM). Experiments with 4-week hypertensive 2K-1C rats show that the vasopressor effect of AngI (10 ng) was decreased by 50 ?g BPP-Cdc (69.7%), and this result was similar to that obtained with 50 ?g BPP9a (69.8%). However, the action duration of BPP-Cdc (60 min) was 2 times greater than that of BPP-9a (30 min). On the other hand, the hypotensive effect of BK (250 ng) was significantly increased by 176.6% after BPP-Cdc (50 ?g) administration, value 2.5 times greater than that obtained with BPP9a administered at the same doses (71.4%). In addition, the duration of the action of BPP-Cdc (120 min) was also at least 4 times greater than that of BPP-9a (30 min). Taken together, these results suggest that BPP-Cdc presents more selective action on arterial blood system than BPP9a. Besides the inhibition of ACE, it may present other mechanisms of action yet to be elucidated. PMID:25091347

Lopes, Denise M; Junior, Norberto E G; Costa, Paula P C; Martins, Patrícia L; Santos, Cláudia F; Carvalho, Ellaine D F; Carvalho, Maria D F; Pimenta, Daniel C; Cardi, Bruno A; Fonteles, Manassés C; Nascimento, Nilberto R F; Carvalho, Krishnamurti M

2014-11-01

257

Diversity, natural history, and geographic distribution of snakes in the Caatinga, Northeastern Brazil.  

PubMed

The present study is a synthesis on snake diversity and distribution in the Caatinga region of northeastern Brazil, providing an updated species list and data on natural history and geographic distribution. Our study is based on the careful revision of 7,102 voucher specimens, housed in 17 herpetological collections, complemented by data on taxonomic literature. We recorded a total of 112 snake species in the Caatinga, belonging to nine families: Anomalepididae, Leptotyphlopidae, Typhlopidae, Aniliidae, Boidae, Viperidae, Elapidae, Colubridae, and Dipsadidae. Our list includes at least 13 never recorded species for this region, as well as distribution records for all species known from the Caatinga (including expansion and new records of distribution). The snake assemblage of the Caatinga is complex, sharing species with other continental open areas (38.4%), forested areas (27.7%), and both open and forested areas (32.1%). The richest areas were isolated plateaus, followed by contact areas, semi-arid caatinga, and sandy dunes of the São Franscisco River. We identified 22 Caatinga endemic species with the sandy dunes of São Franscico River showing the highest endemism level (12 species, with six endemic species restricted to the area) followed by semi-arid caatinga, and isolated plateaus (eight endemic species each, and six and three endemic species with restricted distribution to each area, respectively). Most species show relatively restricted ranges in parts of the Caatinga. The snake assemblage in Caatinga includes mainly terrestrial species (38.4%), followed by fossorial/cryptozoic (26.8%), arboreal/semi-arboreal (26.8%), and aquatic/semi-aquatic (7.1%) species. Vertebrates are the most important dietary item (80.4%), with 56.6% of species being generalist consumers of this kind of prey; 24.4% are frog-eaters, 7.8% prey on caecilians/amphisbaenians, 6.7% lizard-eaters, 3.3% mammal-eaters, and 1.1% are fish-eaters. Only 18.7% of the snakes eat invertebrate prey, as arthropods, annelids, and mollusks. In relation to time of activity, 35.7% of snakes are both diurnal and nocturnal, 33.0% are strictly nocturnal, and 30.4% are diurnal. The data provided herein increase the list of Caatinga snake species from 50 to 112, and includes detailed maps and information on geographic distribution. The Caatinga snake assemblage shows high richness and endemism levels, and our results highlight the usefulness of basic natural history data and revision of voucher specimens as baseline information for biogeographic studies and conservation strategies.  PMID:25283535

Guedes, Thaís B; Nogueira, Cristiano; Marques, Otavio A V

2014-01-01

258

Evaluation of the Lethal Potency of Scorpion and Snake Venoms and Comparison between Intraperitoneal and Intravenous Injection Routes  

PubMed Central

Scorpion stings and snake bites are major health hazards that lead to suffering of victims and high mortality. Thousands of injuries associated with such stings and bites of venomous animals occur every year worldwide. In North Africa, more than 100,000 scorpion stings and snake bites are reported annually. An appropriate determination of the 50% lethal doses (LD50) of scorpion and snake venoms appears to be an important step to assess (and compare) venom toxic activity. Such LD50 values are also commonly used to evaluate the neutralizing capacity of specific anti-venom batches. In the present work, we determined experimentally the LD50 values of reference scorpion and snake venoms in Swiss mice, and evaluated the influence of two main venom injection routes (i.e., intraperitoneal (IP) versus intravenous (IV)). The analysis of experimental LD50 values obtained with three collected scorpion venoms indicates that Androctonus mauretanicus (Am) is intrinsically more toxic than Androctonus australis hector (Aah) species, whereas the latter is more toxic than Buthus occitanus (Bo). Similar analysis of three representative snake venoms of the Viperidae family shows that Cerastes cerastes (Cc) is more toxic than either Bitis arietans (Ba) or Macrovipera lebetina (Ml) species. Interestingly, the venom of Elapidae cobra snake Naja haje (Nh) is far more toxic than viper venoms Cc, Ml and Ba, in agreement with the known severity of cobra-related envenomation. Also, our data showed that viper venoms are about three-times less toxic when injected IP as compared to IV, distinct from cobra venom Nh which exhibited a similar toxicity when injected IP or IV. Overall, this study clearly highlights the usefulness of procedure standardization, especially regarding the administration route, for evaluating the relative toxicity of individual animal venoms. It also evidenced a marked difference in lethal activity between venoms of cobra and vipers, which, apart from the nature of toxins, might be attributed to the rich composition of high molecular weight enzymes in the case of viper venoms. PMID:24926799

Oukkache, Naoual; Jaoudi, Rachid El; Ghalim, Noreddine; Chgoury, Fatima; Bouhaouala, Balkiss; Mdaghri, Naima El; Sabatier, Jean-Marc

2014-01-01

259

Evaluation of the lethal potency of scorpion and snake venoms and comparison between intraperitoneal and intravenous injection routes.  

PubMed

Scorpion stings and snake bites are major health hazards that lead to suffering of victims and high mortality. Thousands of injuries associated with such stings and bites of venomous animals occur every year worldwide. In North Africa, more than 100,000 scorpion stings and snake bites are reported annually. An appropriate determination of the 50% lethal doses (LD50) of scorpion and snake venoms appears to be an important step to assess (and compare) venom toxic activity. Such LD50 values are also commonly used to evaluate the neutralizing capacity of specific anti-venom batches. In the present work, we determined experimentally the LD50 values of reference scorpion and snake venoms in Swiss mice, and evaluated the influence of two main venom injection routes (i.e., intraperitoneal (IP) versus intravenous (IV)). The analysis of experimental LD50 values obtained with three collected scorpion venoms indicates that Androctonus mauretanicus (Am) is intrinsically more toxic than Androctonus australis hector (Aah) species, whereas the latter is more toxic than Buthus occitanus (Bo). Similar analysis of three representative snake venoms of the Viperidae family shows that Cerastes cerastes (Cc) is more toxic than either Bitis arietans (Ba) or Macrovipera lebetina (Ml) species. Interestingly, the venom of Elapidae cobra snake Naja haje (Nh) is far more toxic than viper venoms Cc, Ml and Ba, in agreement with the known severity of cobra-related envenomation. Also, our data showed that viper venoms are about three-times less toxic when injected IP as compared to IV, distinct from cobra venom Nh which exhibited a similar toxicity when injected IP or IV. Overall, this study clearly highlights the usefulness of procedure standardization, especially regarding the administration route, for evaluating the relative toxicity of individual animal venoms. It also evidenced a marked difference in lethal activity between venoms of cobra and vipers, which, apart from the nature of toxins, might be attributed to the rich composition of high molecular weight enzymes in the case of viper venoms. PMID:24926799

Oukkache, Naoual; El Jaoudi, Rachid; Ghalim, Noreddine; Chgoury, Fatima; Bouhaouala, Balkiss; Mdaghri, Naima El; Sabatier, Jean-Marc

2014-06-01

260

Development of 3D full-core ERANOS-2.2/MCNPX-2.7.0 models and neutronic analysis of the BFS-2 zero-power facility  

SciTech Connect

The present paper is addressing the development and validation against experimental data of 3D full-core models of the BFS-2 zero-power fast-reactor using both the deterministic system code ERANOS-2.2 and the stochastic code MCNPX-2.7.0. The model configuration of BFS considered for analysis is the BFS-62-3A benchmark. To extend the - deterministic/stochastic - code-to-code comparison, neutronic parameters, i.e. reactivity, neutron spectrum and reaction rates, were also simulated at the cell level with the Monte Carlo code SERPENT-1.1.7 with two modern data libraries, ENDF-B/VII and JEFF-3.1.1. The BFS-2 critical zero-power facility at the Inst. of Physics and Power Engineering (IPPE) was designed for simulations of the core and shielding of sodium-cooled, fast reactors, for neutron data validation and comparison with experimental results. At the BFS-2 facility, the BFS-62-3A critical benchmark experiment was set-up as a mock-up of the BN-600 reactor, with hybrid MOX fuel and stainless steel reflectors. A UO{sub 2} blanket and a large non-homogeneous stainless-steel reflector surround the core. The lattice is hexagonal of pitch 5.1 cm and metallic dowels are used to keep in central position cylindrical rods made of different types of material (fissile, fertile, blanket, plenum, shielding and absorber). A typical subassembly is formed in piling up various pellets of about 1 cm in height and 4.6 cm in diameter, conferring large heterogeneity in the axial direction. The full-core model development was a complex task due to the large number of subassemblies and the axial subassembly heterogeneity. In ERANOS-2.2, it was necessary to homogenize axially per region the pellets used to form the subassembly. The self-shielded macroscopic cross-sections were calculated using the cell code ECCO in association with JEFF-3.1 and ENDF/B-VI.8 data libraries. The core calculations were performed with broad cross-sections data in 33 neutron energy groups with the solver AVNM in the diffusion approximation, mostly. In MCNPX-2.7.0, a step-by-step approach was used, starting with a model in which the fissile rods were simulated on a homogeneous level, to finally integrate the actual heterogeneous description of the subassemblies. The code-to-code cell analysis performed between ECCO, SERPENT and MCNPX with different modern nuclear data library revealed that the results for the infinite multiplication factor between Monte Carlo and deterministic analysis are in good agreement ({Delta}p < 100 pcm). The differences between the results were observed to be larger for the neutron data libraries, with reactivity differences up to 350 pcm. (authors)

Girardin, G.; Alonso, M. [Ecole Polytechnique Federale de Lausanne EPFL, CH-1015 Lausanne (Switzerland); Mikityuk, K. [Paul Scherrer Institut PSI, CH-5232 Villigen-PSI (Switzerland)

2012-07-01

261

Detecting Mantle Anisotropy with Marine CSEM Sounding  

NASA Astrophysics Data System (ADS)

We can detect transverse electrical anisotropy in the oceanic crust and upper mantle using circular transmitter tows around a pair of highly sensitive controlled-source electromagnetic (CSEM) receivers. Our long-wire electromagnetic (LEM) receivers, equipped with 100-200 m antennas, improve signal to noise by about an order of magnitude over standard EM receivers using 8-10 m antennas. LEMs work well in deep water where voltage noise from electrodes and amplifiers dominates, and electric field noise from magnetotelluric signals and water motion is low. When combined with SUESI, our marine EM transmitter, which emits 300 amps across a 250 m antenna, noise floors of 10-17~V/Am2 may be obtained at 2-4 Hz over 40-minute stacks. Towing a transmitter in a 30 km circle around an orthogonal pair of LEMs samples propagation though the crust and upper mantle in all horizontal directions. This purely azimuthal geometry generates linearly polarized data for an isotropic earth, but in the presence of anisotropy the minor axis of the polarization ellipse develops a characteristic clover-leaf pattern when plotted against source-receiver direction, and the major axis becomes elongated. We have conducted such experiments on 40 Ma lithosphere offshore California (the APPLE experiment), and 24 Ma lithosphere as it subducts into the Nicaraguan trench (part of the SERPENT expedition). Both regions produce remarkably similar results, with increased conductivity in the fossil ridge-parallel directions, which we interpret to be caused by serpentinized mantle-penetrating faults. This pattern of anisotropy is modified in the outer rise of the trench, as the lithosphere bends and shallower (crustal) fractures develop.

Constable, S.; Key, K. W.; Behrens, J. P.; MacGregor, L.; Evans, R. L.

2010-12-01

262

Chemical and isotopic constraints on water/rock interactions at the Lost City hydrothermal field, 30°N Mid-Atlantic Ridge  

NASA Astrophysics Data System (ADS)

Low temperature vent fluids (<91 °C) issuing from the ultramafic-hosted hydrothermal system at Lost City, 30°N Mid-Atlantic Ridge, are enriched in dissolved volatiles (H 2,CH 4) while attaining elevated pH values, indicative of the serpentization processes that govern water/rock interactions deep in the oceanic crust. Here, we present a series of theoretical models to evaluate the extent of hydrothermal alteration and assess the effect of cooling on the systematics of pH-controlled B aqueous species. Peridotite-seawater equilibria calculations indicate that the mineral assemblage composed of diopside, brucite and chrysotile likely dictates fluid pH at moderate temperature serpentinization processes (<300 °C), by imposing constraints on the aCa ++/ a2H + ratios and the activity of dissolved SiO 2. Based on Sr abundances and the 87Sr/ 86Sr isotope ratios of vent fluids reported from Lost City, estimated water/rock mass ratios (w/r = 2-4) are consistent with published models involving dissolved CO 2 and alkane concentrations. Combining the reported ? 18O values of vent fluids (0.7‰) with such w/r mass ratios, allows us to bracket subseafloor reaction temperatures in the vicinity of 250 °C. These estimates are in agreement with previous theoretical studies supporting extensive conductive heat loss within the upflow zones. Experimental studies on peridotite-seawater alteration suggest that fluid pH increases during cooling which then rapidly enhances boron removal from solution and incorporation into secondary phases, providing an explanation for the highly depleted dissolved boron concentrations measured in the low temperature but alkaline Lost City vent fluids. Finally, to account for the depleted 11B composition (? 11B ˜25-30‰) of vent fluids relative to seawater, isotopic fractionation between tetrahedrally coordinated aqueous boron species with BO 3-bearing mineral sites (e.g. in calcite, brucite) is proposed.

Foustoukos, Dionysis I.; Savov, Ivan P.; Janecky, David R.

2008-11-01

263

Hydrogen Isotope Measurements of Organic Acids and Alcohols by Pyrolysis-GC-MS-TC-IRMS: Application to Analysis of Experimentally Derived Hydrothermal Mineral-Catalyzed Organic Products  

NASA Technical Reports Server (NTRS)

We report results of experiments to measure the H isotope composition of organic acids and alcohols. These experiments make use of a pyroprobe interfaced with a GC and high temperature extraction furnace to make quantitative H isotope measurements. This work compliments our previous work that focused on the extraction and analysis of C isotopes from the same compounds [1]. Together with our carbon isotope analyses our experiments serve as a "proof of concept" for making C and H isotope measurements on more complex mixtures of organic compounds on mineral surfaces in abiotic hydrocarbon formation processes at elevated temperatures and pressures. Our motivation for undertaking this work stems from observations of methane detected within the Martian atmosphere [2-5], coupled with evidence showing extensive water-rock interaction during Mars history [6-8]. Methane production on Mars could be the result of synthesis by mineral surface-catalyzed reduction of CO2 and/or CO by Fischer-Tropsch Type (FTT) reactions during serpentization [9,10]. Others have conducted experimental studies to show that FTT reactions are plausible mechanisms for low-molecular weight hydrocarbon formation in hydrothermal systems at mid-ocean ridges [11-13]. Our H isotope measurements utilize an analytical technique combining Pyrolysis-Gas Chromatograph-Mass Spectrometry-High Temperature Conversion-Isotope Ratio Mass Spectrometry (Py-GC-MS-TC-IRMS). This technique is designed to carry a split of the pyrolyzed GC-separated product to a Thermo DSQII quadrupole mass spectrometer as a means of making qualitative and semi-quantitative compositional measurements of separated organic compounds, therefore both chemical and isotopic measurements can be carried out simultaneously on the same sample.

Socki, Richard A.; Fu, Qi; Niles, Paul B.; Gibson, Everett K., Jr.

2012-01-01

264

Failure to restore vision after optic nerve regeneration in reptiles: interspecies variation in response to axotomy.  

PubMed

Optic nerve regeneration within the reptiles is variable. In a snake, Viper aspis, and the lizard Gallotia galloti, regeneration is slow, although some retinal ganglion cell (RGC) axons eventually reach the visual centers (Rio et al. [1989] Brain Res 479:151-156; Lang et al. [1998] Glia 23:61-74). By contrast, in a lizard, Ctenophorus ornatus, numerous RGC axons regenerate rapidly to the visual centers, but unless animals are stimulated visually, the regenerated projection lacks topography and animals remain blind via the experimental eye (Beazley et al. [2003] J. Neurotrauma 20:1263-1269). V. aspis, G. galloti, and C. ornatus belong respectively to the Serpentes, Lacertidae, and Agamidae within the Eureptilia, the major modern group of living reptiles comprising the Squamata (snakes, lizards, and geckos) and the Crocodyllia. Here we have extended the findings on Eureptilia to include two geckos (Gekkonidae), Cehyra variegata and Nephrurus stellatus. We also examined a turtle, Chelodina oblonga, the Testudines being the sole surviving representatives of the Parareptilia, the more ancient reptilian group. In all three species, visually elicited behavioral responses were absent throughout regeneration, a result supported electrophysiologically; axonal tracing revealed that only a small proportion of RGC axons crossed the lesion and none entered the contralateral optic tract. RGC axons failed to reach the chiasm in C. oblonga, and in G. variegata, and N. stellatus RGC axons entered the opposite optic nerve; a limited ipsilateral projection was seen in G. variegata. Our results support a heterogeneous response to axotomy within the reptiles, each of which is nevertheless dysfunctional. PMID:15368531

Dunlop, Sarah A; Tee, Lisa B G; Stirling, R Victoria; Taylor, Andrew L; Runham, Phil B; Barber, Andy B; Kuchling, Gerald; Rodger, Jenny; Roberts, J Dale; Harvey, Alan R; Beazley, Lyn D

2004-10-18

265

Transmutation Analysis of Enriched Uranium and Deep Burn High Temperature Reactors  

SciTech Connect

High temperature reactors (HTRs) have been under consideration for production of electricity, process heat, and for destruction of transuranics for decades. As part of the transmutation analysis efforts within the Fuel Cycle Research and Development (FCR&D) campaign, a need was identified for detailed discharge isotopics from HTRs for use in the VISION code. A conventional HTR using enriched uranium in UCO fuel was modeled having discharge burnup of 120 GWd/MTiHM. Also, a deep burn HTR (DB-HTR) was modeled burning transuranic (TRU)-only TRU-O2 fuel to a discharge burnup of 648 GWd/MTiHM. For each of these cases, unit cell depletion calculations were performed with SCALE/TRITON. Unit cells were used to perform this analysis using SCALE 6.1. Because of the long mean free paths (and migration lengths) of neutrons in HTRs, using a unit cell to represent a whole core can be non-trivial. The sizes of these cells were first set by using Serpent calculations to match a spectral index between unit cell and whole core domains. In the case of the DB-HTR, the unit cell which was arrived at in this way conserved the ratio of fuel to moderator found in a single block of fuel. In the conventional HTR case, a larger moderator-to-fuel ratio than that of a single block was needed to simulate the whole core spectrum. Discharge isotopics (for 500 nuclides) and one-group cross-sections (for 1022 nuclides) were delivered to the transmutation analysis team. This report provides documentation for these calculations. In addition to the discharge isotopics, one-group cross-sections were provided for the full list of 1022 nuclides tracked in the transmutation library.

Michael A. Pope

2012-07-01

266

Phylogeography of the Mekong mud snake (Enhydris subtaeniata): the biogeographic importance of dynamic river drainages and fluctuating sea levels for semiaquatic taxa in Indochina  

PubMed Central

During the Cenozoic, Southeast Asia was profoundly affected by plate tectonic events, dynamic river systems, fluctuating sea levels, shifting coastlines, and climatic variation, which have influenced the ecological and evolutionary trajectories of the Southeast Asian flora and fauna. We examined the role of these paleogeographic factors on shaping phylogeographic patterns focusing on a species of semiaquatic snake, Enhydris subtaeniata (Serpentes: Homalopsidae) using sequence data from three mitochondrial fragments (cytochrome b, ND4, and ATPase—2785 bp). We sampled E. subtaeniata from seven locations in three river drainage basins that encompassed most of this species’ range. Genetic diversities were typically low within locations but high across locations. Moreover, each location had a unique suite of haplotypes not shared among locations, and pairwise ?ST values (0.713–0.998) were highly significant between all location pairs. Relationships among phylogroups were well resolved and analysis of molecular variance (AMOVA) revealed strong geographical partitioning of genetic variance among the three river drainage basins surveyed. The genetic differences observed among the populations of E. subtaeniata were likely shaped by the Quaternary landscapes of Indochina and the Sunda Shelf. Historically, the middle and lower Mekong consisted of strongly dissected river valleys separated by low mountain ranges and much of the Sunda Shelf consisted of lowland river valleys that served to connect faunas associated with major regional rivers. It is thus likely that the contemporary genetic patterns observed among populations of E. subtaeniata are the result of their histories in a complex terrain that created abundant opportunities for genetic isolation and divergence yet also provided lowland connections across now drowned river valleys. PMID:22393504

Lukoschek, Vimoksalehi; Osterhage, Jennifer L; Karns, Daryl R; Murphy, John C; Voris, Harold K

2011-01-01

267

Chimeric creatures in Greek mythology and reflections in science.  

PubMed

"The Chimaera" in Homer's Iliad, "was of divine stock, not of men, in the forepart a lion, in the hinder a serpent, and in the midst a goat, ellipsis Bellerophon slew her, trusting in the signs of the gods." In Hesiod's Theogony it is emphasized that "Chimaera ellipsis had three heads, one of a grim-eyed lion, another of a goat, and another of a snakeellipsis". In addition to this interspecies animal chimera, human/animal chimeras are referred to in Greek mythology, preeminent among them the Centaurs and the Minotaur. The Centaurs, as horse/men, first appear in Geometric and early Archaic art, but in the literature not until early in the fifth century B.C. The bullheaded-man Minotaur, who is not certainly attested in the literary evidence until circa 500 B.C., first appears in art about 650 B.C. Attempts, in the fourth century B.C. and thereafter, to rationalize their mythical appearance were in vain; their chimeric nature retained its fascinating and archetypal form over the centuries. Early in the 1980s, experimental sheep/goat chimeras were produced removing the reproductive barrier between these two animal species. Late in the 1990s, legal, political, ethical, and moral fights loomed over a patent bid on human/animal chimeras. Chimeric technology is recently developed; however, the concept of chimerism has existed in literary and artistic form in ancient mythology. This is yet another example where art and literature precede scientific research and development. PMID:11337752

Bazopoulou-Kyrkanidou, E

2001-04-15

268

Depletion Analysis of Modular High Temperature Gas-cooled Reactor Loaded with LEU/Thorium Fuel  

SciTech Connect

Thorium based fuel has been considered as an option to uranium-based fuel, based on considerations of resource utilization (Thorium is more widely available when compared to Uranium). The fertile isotope of Thorium (Th-232) can be converted to fissile isotope U-233 by neutron capture during the operation of a suitable nuclear reactor such as High Temperature Gas-cooled Reactor (HTGR). However, the fertile Thorium needs a fissile supporter to start and maintain the conversion process such as U-235 or Pu-239. This report presents the results of a study that analyzed the thorium utilization in a prismatic HTGR, namely Modular High Temperature Gas-Cooled Reactor (MHTGR) that was designed by General Atomics (GA). The collected for the modeling of this design come from Chapter 4 of MHTGR Preliminary Safety Information Document that GA sent to Department of Energy (DOE) on 1995. Both full core and unit cell models were used to perform this analysis using SCALE 6.1 and Serpent 1.1.18. Because of the long mean free paths (and migration lengths) of neutrons in HTRs, using a unit cell to represent a whole core can be non-trivial. The sizes of these cells were set to match the spectral index between unit cell and full core domains. It was found that for the purposes of this study an adjusted unit cell model is adequate. Discharge isotopics and one-group cross-sections were delivered to the transmutation analysis team. This report provides documentation for these calculations

Sonat Sen; Gilles Youinou

2013-02-01

269

Optimizing the implementation of the target motion sampling temperature treatment technique - How fast can it get?  

SciTech Connect

This article discusses the optimization of the target motion sampling (TMS) temperature treatment method, previously implemented in the Monte Carlo reactor physics code Serpent 2. The TMS method was introduced in [1] and first practical results were presented at the PHYSOR 2012 conference [2]. The method is a stochastic method for taking the effect of thermal motion into account on-the-fly in a Monte Carlo neutron transport calculation. It is based on sampling the target velocities at collision sites and then utilizing the 0 K cross sections at target-at-rest frame for reaction sampling. The fact that the total cross section becomes a distributed quantity is handled using rejection sampling techniques. The original implementation of the TMS requires 2.0 times more CPU time in a PWR pin-cell case than a conventional Monte Carlo calculation relying on pre-broadened effective cross sections. In a HTGR case examined in this paper the overhead factor is as high as 3.6. By first changing from a multi-group to a continuous-energy implementation and then fine-tuning a parameter affecting the conservativity of the majorant cross section, it is possible to decrease the overhead factors to 1.4 and 2.3, respectively. Preliminary calculations are also made using a new and yet incomplete optimization method in which the temperature of the basis cross section is increased above 0 K. It seems that with the new approach it may be possible to decrease the factors even as low as 1.06 and 1.33, respectively, but its functionality has not yet been proven. Therefore, these performance measures should be considered preliminary. (authors)

Tuomas, V.; Jaakko, L. [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT (Finland)

2013-07-01

270

High conversion Th-U{sup 233} fuel assembly for current generation of PWRs  

SciTech Connect

This paper presents a preliminary design of a high conversion Th-U{sup 233} fuel assembly applicable for current generation of Pressurized Water Reactor (PWRs). The considered fuel assembly has a typical 17 x 17 PWR lattice. However in order to increase the conversion of Th{sup 232} to U{sup 233}, the assembly was subdivided into the two regions called seed and blanket. The central seed region has a higher than blanket U{sup 233} content and acts as a neutron source for the peripheral blanket region. The latest acts as a U{sup 233} breeder. While the seed fuel pins have a standard dimensions the blanket fuel radius was increased in order to reduce the moderation and to facilitate the resonance neutron absorption in blanket Th{sup 232}. The U{sup 233} content in the seed and blanket regions was optimized to achieve maximal initial to discharged fissile inventory ratio (FIR) taking into account the target fuel cycle length of 12 months with 3-batch reloading scheme. In this study the neutronic calculations were performed on the fuel assembly level using Helios deterministic lattice transport code. The fuel cycle length and the core k{sub eff} were estimated by applying the Non Linear Reactivity Model. The applicability of the HELIOS code for the analysis of the Th-based high conversion designs was confirmed with the help of continuous-energy Monte-Carlo code SERPENT. The results of optimization studies show that for the heterogeneous seed and blanket (SB) fuel assembly the FIR of about 0.95 can be achieved. (authors)

Baldova, D.; Fridman, E. [Reactor Safety Div., Helmholtz-Zentrum Dresden-Rossendorf, POB 510119, Dresden, 01314 (Germany)

2012-07-01

271

Carbon Isotopes of Alkanes in Hydrothermal Abiotic Organic Synthesis Processes at High Temperatures and Pressures: An Experimental Study  

NASA Technical Reports Server (NTRS)

Observation of methane in the Martian atmosphere has been reported by different detection techniques [1-4]. With more evidence showing extensive water-rock interaction in Martian history [5-7], abiotic formation by Fischer-Tropsch Type (FTT) synthesis during serpentization reactions may be one possible process responsible for methane generation on Mars [8, 9]. While the experimental studies performed to date leave little doubt that chemical reactions exist for the abiotic synthesis of organic compounds by mineral surface-catalyzed reactions [10-12], little is known about the reaction pathways by which CO2 and/or CO are reduced under hydrothermal conditions. Carbon and hydrogen isotope measurements of alkanes have been used as an effective tool to constrain the origin and reaction pathways of hydrocarbon formation. Alkanes generated by thermal breakdown of high molecular weight organic compounds have carbon and hydrogen isotopic signatures completely distinct from those formed abiotically [13-15]. Recent experimental studies, however, showed that different abiogenic hydrocarbon formation processes (e.g., polymerization vs. depolymerization) may have different carbon and hydrogen isotopic patterns [16]. Results from previous experiments studying decomposition of higher molecular weight organic compounds (lignite) also suggested that pressure could be a crucial factor affecting fractionation of carbon isotopes [17]. Under high pressure conditions, no experimental data are available describing fractionation of carbon isotope during mineral catalyzed FTT synthesis. Thus, hydrothermal experiments present an excellent opportunity to provide the requisite carbon isotope data. Such data can also be used to identify reaction pathways of abiotic organic synthesis under experimental conditions.

Fu, Qi; Socki, Richard A.; Niles, Paul B.

2010-01-01

272

Antioxidants Maintain E-Cadherin Levels to Limit Drosophila Prohemocyte Differentiation  

PubMed Central

Mitochondrial reactive oxygen species (ROS) regulate a variety of biological processes by networking with signal transduction pathways to maintain homeostasis and support adaptation to stress. In this capacity, ROS have been shown to promote the differentiation of progenitor cells, including mammalian embryonic and hematopoietic stem cells and Drosophila hematopoietic progenitors (prohemocytes). However, many questions remain about how ROS alter the regulatory machinery to promote progenitor differentiation. Here, we provide evidence for the hypothesis that ROS reduce E-cadherin levels to promote Drosophila prohemocyte differentiation. Specifically, we show that knockdown of the antioxidants, Superoxide dismutatase 2 and Catalase reduce E-cadherin protein levels prior to the loss of Odd-skipped-expressing prohemocytes. Additionally, over-expression of E-cadherin limits prohemocyte differentiation resulting from paraquat-induced oxidative stress. Furthermore, two established targets of ROS, Enhancer of Polycomb and FOS, control the level of E-cadherin protein expression. Finally, we show that knockdown of either Superoxide dismutatase 2 or Catalase leads to an increase in the E-cadherin repressor, Serpent. As a result, antioxidants and targets of ROS can control E-cadherin protein levels, and over-expression of E-cadherin can ameliorate the prohemocyte response to oxidative stress. Collectively, these data strongly suggest that ROS promote differentiation by reducing E-cadherin levels. In mammalian systems, ROS promote embryonic stem cell differentiation, whereas E-cadherin blocks differentiation. However, it is not known if elevated ROS reduce E-cadherin to promote embryonic stem cell differentiation. Thus, our findings may have identified an important mechanism by which ROS promote stem/progenitor cell differentiation. PMID:25226030

Gao, Hongjuan; Wu, Xiaorong; Simon, LaTonya; Fossett, Nancy

2014-01-01

273

STELLAR 'EGGS' EMERGE FROM MOLECULAR CLOUD (Star-Birth Clouds in M16)  

NASA Technical Reports Server (NTRS)

This eerie, dark structure, resembling an imaginary sea serpent's head, is a column of cool molecular hydrogen gas (two atoms of hydrogen in each molecule) and dust that is an incubator for new stars. The stars are embedded inside finger-like protrusions extending from the top of the nebula. Each 'fingertip' is somewhat larger than our own solar system. The pillar is slowly eroding away by the ultraviolet light from nearby hot stars, a process called 'photoevaporation'. As it does, small globules of especially dense gas buried within the cloud is uncovered. These globules have been dubbed 'EGGs' -- an acronym for 'Evaporating Gaseous Globules'. The shadows of the EGGs protect gas behind them, resulting in the finger-like structures at the top of the cloud. Forming inside at least some of the EGGs are embryonic stars -- stars that abruptly stop growing when the EGGs are uncovered and they are separated from the larger reservoir of gas from which they were drawing mass. Eventually the stars emerge, as the EGGs themselves succumb to photoevaporation. The stellar EGGS are found, appropriately enough, in the 'Eagle Nebula' (also called M16 -- the 16th object in Charles Messier's 18th century catalog of 'fuzzy' permanent objects in the sky), a nearby star-forming region 6,500 light-years away in the constellation Serpens. The picture was taken on April 1, 1995 with the Hubble Space Telescope Wide Field and Planetary Camera 2. The color image is constructed from three separate images taken in the light of emission from different types of atoms. Red shows emission from singly-ionized sulfur atoms. Green shows emission from hydrogen. Blue shows light emitted by doubly- ionized oxygen atoms. Credit: Jeff Hester and Paul Scowen (Arizona State University), and NASA Image files in GIF and JPEG format and captions may be accessed on Internet via anonymous ftp from oposite.stsci.edu in /pubinfo:

2002-01-01

274

Polarimetry of sunspot penumbrae with high spatial resolution  

NASA Astrophysics Data System (ADS)

We present two-dimensional high-spatial-resolution spectropolarimetric observations of sunspot penumbrae. They were obtained in April 2002 and May 2003 with the "Göttingen" Fabry-Pérot spectrometer at the Vacuum Tower Telescope at the Observatorio del Teide (Tenerife). Speckle methods were applied for image reconstruction which resulted in a spatial resolution of 0.5 arcsec in the magnetograms of the penumbrae. We analysed Stokes I and V profiles of the Fe II 6149 Å line, which exhibits no instrumental Stokes Q/U? V crosstalk, and of the Fe I line pair at 6302 Å. The main results are the following: 1) on scales larger than 0.5 arcsec, the intensity pattern of penumbrae stays the same in the continuum and core images of the 6301.5 Å line, which stem from 0 km and 300 km (above ?_5=1), respectively. Yet at scales of 0.5 arcsec and smaller the pattern in the two spectral features is clearly different. 2) On the limb side of sunspots the Evershed flow is carried by dark filaments and on the centre side by bright features and their somewhat weakened tails. We explain this with a picture in which the velocity of hot rising gas is best seen on the centre side, while on the limb side the horizontal outward and possibly downward flows are seen when the gas has cooled down. 3) The un-combed structure of the magnetic field is confirmed. On the limb side, the more horizontal fields coincide with dark fibrils or with diffuse intensity structures. Generally, the more horizontal fields are located at the positions of strong outflows. 4) Strong line-of-sight components of the magnetic fields are not found in bright filaments but in dark structures, somewhat displaced from the darkest parts. Their positions do not coincide with those of the strongest velocity fields. In general, our results are compatible with the picture of low lying flow channels coincident with the horizontal magnetic field, or possibly emerging and diving down into sub-photospheric layers, like a "sea serpent". Some further dynamic phenomena are discussed, which demonstrate the richness of processes in penumbrae, and reveal unexpected properties.

Bello González, N.; Okunev, O. V.; Domínguez Cerdeña, I.; Kneer, F.; Puschmann, K. G.

2005-04-01

275

Deterministic Modeling of the High Temperature Test Reactor  

SciTech Connect

Idaho National Laboratory (INL) is tasked with the development of reactor physics analysis capability of the Next Generation Nuclear Power (NGNP) project. In order to examine INL’s current prismatic reactor deterministic analysis tools, the project is conducting a benchmark exercise based on modeling the High Temperature Test Reactor (HTTR). This exercise entails the development of a model for the initial criticality, a 19 column thin annular core, and the fully loaded core critical condition with 30 columns. Special emphasis is devoted to the annular core modeling, which shares more characteristics with the NGNP base design. The DRAGON code is used in this study because it offers significant ease and versatility in modeling prismatic designs. Despite some geometric limitations, the code performs quite well compared to other lattice physics codes. DRAGON can generate transport solutions via collision probability (CP), method of characteristics (MOC), and discrete ordinates (Sn). A fine group cross section library based on the SHEM 281 energy structure is used in the DRAGON calculations. HEXPEDITE is the hexagonal z full core solver used in this study and is based on the Green’s Function solution of the transverse integrated equations. In addition, two Monte Carlo (MC) based codes, MCNP5 and PSG2/SERPENT, provide benchmarking capability for the DRAGON and the nodal diffusion solver codes. The results from this study show a consistent bias of 2–3% for the core multiplication factor. This systematic error has also been observed in other HTTR benchmark efforts and is well documented in the literature. The ENDF/B VII graphite and U235 cross sections appear to be the main source of the error. The isothermal temperature coefficients calculated with the fully loaded core configuration agree well with other benchmark participants but are 40% higher than the experimental values. This discrepancy with the measurement stems from the fact that during the experiments the control rods were adjusted to maintain criticality, whereas in the model, the rod positions were fixed. In addition, this work includes a brief study of a cross section generation approach that seeks to decouple the domain in order to account for neighbor effects. This spectral interpenetration is a dominant effect in annular HTR physics. This analysis methodology should be further explored in order to reduce the error that is systematically propagated in the traditional generation of cross sections.

Ortensi, J.; Cogliati, J. J.; Pope, M. A.; Ferrer, R. M.; Ougouag, A. M.

2010-06-01

276

Hubble Unveils Colorful and Turbulent Star-Birth Region on 100,000th Orbit Milestone  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site] Click on the image for orientation annotation

In commemoration of NASA's Hubble Space Telescope completing its 100,000th orbit in its 18th year of exploration and discovery, scientists at the Space Telescope Science Institute in Baltimore, Md., have aimed Hubble totake a snapshot of a dazzling region of celestial birth and renewal.

Hubble peered into a small portion of the nebula near the star cluster NGC 2074 (upper, left). The region is a firestorm of raw stellar creation, perhaps triggered by a nearby supernova explosion. It lies about 170,000 light-years away near the Tarantula nebula, one of the most active star-forming regions in our Local Group of galaxies.

The three-dimensional-looking image reveals dramatic ridges and valleys of dust, serpent-head 'pillars of creation,' and gaseous filaments glowing fiercely under torrential ultraviolet radiation. The region is on the edge of a dark molecular cloud that is an incubator for the birth of new stars.

The high-energy radiation blazing out from clusters of hot young stars already born in NGC 2074 is sculpting the wall of the nebula by slowly eroding it away. Another young cluster may be hidden beneath a circle of brilliant blue gas at center, bottom.

In this approximately 100-light-year-wide fantasy-like landscape, dark towers of dust rise above a glowing wall of gases on the surface of the molecular cloud. The seahorse-shaped pillar at lower, right is approximately 20 light-years long, roughly four times the distance between our Sun and the nearest star, Alpha Centauri.

The region is in the Large Magellanic Cloud (LMC), a satellite of our Milky Way galaxy. It is a fascinating laboratory for observing star-formation regions and their evolution. Dwarf galaxies like the LMC are considered to be the primitive building blocks of larger galaxies.

This representative color image was taken on August 10, 2008, with Hubble's Wide Field Planetary Camera 2. Red shows emission from sulfur atoms, green from glowing hydrogen, and blue from glowing oxygen.

2008-01-01

277

Profiling the venom gland transcriptomes of Costa Rican snakes by 454 pyrosequencing  

PubMed Central

Background A long term research goal of venomics, of applied importance for improving current antivenom therapy, but also for drug discovery, is to understand the pharmacological potential of venoms. Individually or combined, proteomic and transcriptomic studies have demonstrated their feasibility to explore in depth the molecular diversity of venoms. In the absence of genome sequence, transcriptomes represent also valuable searchable databases for proteomic projects. Results The venom gland transcriptomes of 8 Costa Rican taxa from 5 genera (Crotalus, Bothrops, Atropoides, Cerrophidion, and Bothriechis) of pitvipers were investigated using high-throughput 454 pyrosequencing. 100,394 out of 330,010 masked reads produced significant hits in the available databases. 5.165,220 nucleotides (8.27%) were masked by RepeatMasker, the vast majority of which corresponding to class I (retroelements) and class II (DNA transposons) mobile elements. BLAST hits included 79,991 matches to entries of the taxonomic suborder Serpentes, of which 62,433 displayed similarity to documented venom proteins. Strong discrepancies between the transcriptome-computed and the proteome-gathered toxin compositions were obvious at first sight. Although the reasons underlaying this discrepancy are elusive, since no clear trend within or between species is apparent, the data indicate that individual mRNA species may be translationally controlled in a species-dependent manner. The minimum number of genes from each toxin family transcribed into the venom gland transcriptome of each species was calculated from multiple alignments of reads matched to a full-length reference sequence of each toxin family. Reads encoding ORF regions of Kazal-type inhibitor-like proteins were uniquely found in Bothriechis schlegelii and B. lateralis transcriptomes, suggesting a genus-specific recruitment event during the early-Middle Miocene. A transcriptome-based cladogram supports the large divergence between A. mexicanus and A. picadoi, and a closer kinship between A. mexicanus and C. godmani. Conclusions Our comparative next-generation sequencing (NGS) analysis reveals taxon-specific trends governing the formulation of the venom arsenal. Knowledge of the venom proteome provides hints on the translation efficiency of toxin-coding transcripts, contributing thereby to a more accurate interpretation of the transcriptome. The application of NGS to the analysis of snake venom transcriptomes, may represent the tool for opening the door to systems venomics. PMID:21605378

2011-01-01

278

Snake Venom  

NSDL National Science Digital Library

The following collection of Web sites explores the properties and novel medical uses of snake venom. The first Web site (1), a ThinkQuest prizewinner, is one part of a well-crafted and informative guide to the earth's poisonous plants and animals. This particular Web page offers a good introduction to snake venom, including a table detailing the effect and concentration of the different proteins found in venom that can kill or paralyze prey. The next Web site comes from The Reptile House, a commercial breeder and supplier of reptiles and amphibians, and presents photos and facts about the ten deadliest snakes on the planet (2). A straightforward description of the three types of venomous snakes (opisthoglyphs, proteroglyphs, and solenoglyphs) and a short overview of the properties of venom is available from www.venomous.com, a privately hosted Web site (3). The next Web site comes from the online companion to the PBS Nature documentary: The Serpent's Tooth (4). The site contains an engaging article about the intrepid Bill Haast, director of the Miami Serpentarium, who "has been bitten by venomous snakes more than 160 times -- and lived to tell the tale." Howard Reinert, another snake biologist and (surprise!) snakebite victim, relates his experiences with a "dry" bite and the real thing in the next Web site from AnimalPlanet.com (5). The site also includes audio segments of experts discussing the physiological effects of snake venom and what to do if bitten by a rattlesnake. Is rattlesnake venom evolving? Research suggests that North American rattlesnake venom has become increasingly potent -- the focus of an interesting article from the American Museum of Natural History (6). The article also provides a detailed introduction to rattlesnakes and their deadly venom. Scientists around the world have been exploring the possible medicinal uses of venom, and not just for antivenin. The last two Web sites relate just some of the work being done in this area. The BBC news article recounts efforts to determine whether certain snake venoms contain chemicals that could prevent heart attacks and strokes (7). Likewise, scientists at the Howard Hughes Medical Center (8) have found a protein in snake venom that could offer a way to explore how nicotine and other drugs turn on the "pleasure centers" of the brain.

Sohmer, Rachel.

2003-01-01

279

Clear New View of a Classic Spiral  

NASA Astrophysics Data System (ADS)

ESO is releasing a beautiful image of the nearby galaxy Messier 83 taken by the HAWK-I instrument on ESO's Very Large Telescope (VLT) at the Paranal Observatory in Chile. The picture shows the galaxy in infrared light and demonstrates the impressive power of the camera to create one of the sharpest and most detailed pictures of Messier 83 ever taken from the ground. The galaxy Messier 83 (eso0825) is located about 15 million light-years away in the constellation of Hydra (the Sea Serpent). It spans over 40 000 light-years, only 40 percent the size of the Milky Way, but in many ways is quite similar to our home galaxy, both in its spiral shape and the presence of a bar of stars across its centre. Messier 83 is famous among astronomers for its many supernovae: vast explosions that end the lives of some stars. Over the last century, six supernovae have been observed in Messier 83 - a record number that is matched by only one other galaxy. Even without supernovae, Messier 83 is one of the brightest nearby galaxies, visible using just binoculars. Messier 83 has been observed in the infrared part of the spectrum using HAWK-I [1], a powerful camera on ESO's Very Large Telescope (VLT). When viewed in infrared light most of the obscuring dust that hides much of Messier 83 becomes transparent. The brightly lit gas around hot young stars in the spiral arms is also less prominent in infrared pictures. As a result much more of the structure of the galaxy and the vast hordes of its constituent stars can be seen. This clear view is important for astronomers looking for clusters of young stars, especially those hidden in dusty regions of the galaxy. Studying such star clusters was one of the main scientific goals of these observations [2]. When compared to earlier images, the acute vision of HAWK-I reveals far more stars within the galaxy. The combination of the huge mirror of the VLT, the large field of view and great sensitivity of the camera, and the superb observing conditions at ESO's Paranal Observatory makes HAWK-I one of the most powerful near-infrared imagers in the world. Astronomers are eagerly queuing up for the chance to use the camera, which began operation in 2007 (eso0736), and to get some of the best ground-based infrared images ever of the night sky. Notes [1] HAWK-I stands for High-Acuity Wide-field K-band Imager. More technical details about the camera can be found in an earlier press release (eso0736). [2] The data used to prepare this image were acquired by a team led by Mark Gieles (University of Cambridge) and Yuri Beletsky (ESO). Mischa Schirmer (University of Bonn) performed the challenging data processing. More information ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world's most productive astronomical observatory. It is supported by 14 countries: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world's most advanced visible-light astronomical observatory and VISTA, the world's largest survey telescope. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 42-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become "the world's biggest eye on the sky".

2010-05-01

280

Broken formations, melanges and olistostromes in Puerto Plata area (Northern Dominican Republic) as a record of subduction and collisional processes between the Caribbean and North-American plates  

NASA Astrophysics Data System (ADS)

The Northern Cordillera of the Dominican Republic records the (oblique) subduction and collisional processes occurred between the Caribbean and North-American plates during Upper Cretaceous to Lower Paleogene times. The boundary between these two plates can be traced within this range disrupted by an Upper Paleogene to present intense left-lateral strike-slip tectonism, onset after collision. In the western part of the range this boundary might be defined by the Camu fault. In the coastal area of Puerto Plata, located on the northern block of the Camu fault, basement rocks belonging to the subducting plate (the Puerto Plata Basement Complex) and several related units probably formed in an accretionary prism, preserve in a large (300 km2) outcrop of chaotic formations presumably formed (and exhumed) during collision. They include from broken formations and tectonic melanges to olistostromes and other coeval sedimentary deposits. The Puerto Plata Basement Complex (PPBC) consists of highly faulted and dismembered blocks formed by discontinuous but sometimes coherent outcrops of serpentinized or massive peridotite, pods of ultramafic cumulates, massive or banded gabbros and Los Caños Fm, a thick sequence of gross bedded volcaniclastic material with interbedded basaltic (sometimes pillowed) or andesitic flows. All these rocks bear low grade metamorphism and lack a general deformation fabric apart from occasional transformation to mylonites due to localized shearing. The PPBC has been interpreted as a fragment of oceanic crust, belonging to the subducting (North-American) slab that has been exhumed as a tectonic melange or a broken complex. The Imbert Fm, of Palaeocene-Eocene age, is formed by a well bedded succession of white very fine grained porcelaneous tuffs, with eventual intercalations of cherts, limestones and marls that, towards the lower part, is interbedded with volcanic-derived graywackes and limolites, and more occasionally, thick beds of conglomerates and debris. These last ones typically incorporate fragments of serpentized peridotites and blocks of the volcanic rocks identified in the PPBC. The Imbert Fm is also internally disrupted and although not a single clear contact can be observed in the field, it is considered to rest unconformably over the complex, so postdating its exhumation. A separate mappable unit of serpentinitic brecchias has recently been identified mainly distributed along the outer limits of the PPBC but also in several scattered outcrops inside it. The unit is dominantly made of fragments and blocks of serpentinized peridotites, embedded in an abundant matrix of the same composition and includes also blocks of Los Caños and Imbert Fm, as well as other exotic blocks of unknown origin. In the southeastern limit of the complex, close to the Camu fault, there is a particular high concentration of exotic blocks derived from metamorphic rocks (greenschists, anfibolites, marbles and even blueschists) not exposed in any neighbouring areas and thus suggesting a deep-sited, subduction-related, feeding. The basal contact of this unit with the rocks of the PPBC is usually faulted and difficult to observe in the field, but cartographic patterns suggest that it is an unconformity. Outcrops of serpentinitic breccias show a wide variety of internal chaotic organization, from pods of tectonic melanges to the most frequent block-in matrix fabric, but most of them also show evidences of sedimentary rework. In the easternmost part of the PPBC, the serpentinitic brecchias are, in turn, the base of an olistostromic complex widely represented in the region, the San Marcos Fm. The olistostrome includes similar exotic blocks than observed in the serpentinitic brecchias and blocks and olistolithes derived from the PPBC but, mainly, from the Imbert Fm. According to the described relationships, the serpentinitic breccias and San Marcos olistostrome are considered partially coeval and laterally equivalent to the Imbert Fm.

Hernaiz Huerta, Pedro Pablo; Valera Fernando, Pérez; de Los Santos Manuel, Abad; Jacques, Monthel; de Neira Alberto, Díaz

2010-05-01

281

An update review on Commiphora molmol and related species.  

PubMed

The origins of myrrh and frankincense are traced to the Arabian Peninsula. According to Herodotus (5th century BC): "Arabia is the only country which produces frankincense, myrrh, cassia, and cinnamon.., the trees bearing the frankincense are guarded by winged serpents of small size and various colors." Diodorus Siculus wrote, in the second half of the first century BC, that "all of Arabia exudes a most delicate fragrance; even the seamen passing by Arabia can smell the strong fragrance that gives health and vigor." He also mentioned gold mines so pure that no smelting was necessary. The Magi, carrying myrrh, frankincense, and gold, came from the East: Arabia. The frankincense trade route, with transport by donkeys and later by camel caravans, reached Jerusalem and Egypt from the Dhofar region of what is today Oman, through Yemen, turning north to follow the Red Sea coast. It is likely that the same or similar species of the resin-bearing plants grew across the Red Sea in the area that is now Somalia and Ethiopia, while the collection of the gum resins was initiated in Arabia. Myrrh contributed much in the human welfare. Schistosomiasis was known in ancient Egypt since remote times. Haematuria with urinary bladder disturbances was mentioned in four Papyrus papers dated back to 1950-1900 BC, and Schistosoma ova was detected in a cirrhotic liver of a mummy from 1200 BC (Ruffer, 1910). Also, Fasciola eggs were detected in a mummy (Looss, 1896). Fascioliasis infected over 17 million people worldwide causing marked morbidity and mortality (Haseeb et al., 2002). Schistosomiasis affected over 200 million people in 74 countries and territories worldwide (WHO, 1999) causing several chronic complications. Both were incriminated to predispose or accompanied human hepatitis and predisposed to HCV (Wahib et al., 2006). Most zoonotic helminthes induced immune response (Nutman, 2001) characterized by producing of type 2 cytokines, Ig G1, IgG2, IgE antibodies and eosinophil and mast cell activation (Hoffman et al., 2002). Treatment of fascioliasis required high or drug multiple doses with side effect (Farid et al., 1990). In schistosomiasis, praziquantel (PZQ) in use for > 20 years was faced with low efficacy (Leishout et al., 1998), or with increased resistance (Coles et al., 1986; Watt et al., 1988; Herrera et al., 1994; Ismail et al., 1994; 1999; Tonelli et al., 1995; Stelma et al., 1995; Fallon et al., 1997; Bennett et al., 1997; Boisier et al., 1998; Periera et al., 1998; Kusel and Hagan, 1999; Liang et al., 2000; King et al., 2000; N'Goran et al., 2003; Raso et al., 2004), potentiality of carcinogenicity, genotoxicity (Rosenkranz et al., 1995), mutagenicity (Montero et al., 1993), big dose lethality and enhanced clastogenicity of environmental pollutants (Anwar, 1994). On the other hand, Nomicos (2007) in USA reported that since antiquity, the genus Commiphora is composed of more than 200 species, and exploited as a natural drug to treat pain, skin infections, inflammatory conditions, diarrhea, and periodontal diseases. He added that in more recent history, products derived from C. myrrha and various other species of Commiphora are becoming recognized to possess significant antiseptic, anesthetic, and antitumor properties. Traditional practice and evidence-based research have supported that these properties are directly attributable to terpenoids (especially furanoses-quiterpenes), the active compounds present in myrrh essential oil. Very recently, current studies have focused on applying clinical trial methodologies to validate its use as an antineoplastic, an antiparasitic agent, and as an adjunct in healing wounds. Weeks and Simpson (2007) in USA presented the molecular phylogeny of Commiphora, a predominantly tropical African, arid-adapted tree genus to test the monophyly of its taxonomic sections and to identify clades to help direct future study of this species-rich and geographically widespread taxon. The multiple fossil calibrations of Commiphora phylogeny proved that it is sister to Vietnamese Burse

Tonkal, Abdulkader M D; Morsy, Tosson A

2008-12-01

282

Application de la methode des sous-groupes au calcul Monte-Carlo multigroupe  

NASA Astrophysics Data System (ADS)

This thesis is dedicated to the development of a Monte Carlo neutron transport solver based on the subgroup (or multiband) method. In this formalism, cross sections for resonant isotopes are represented in the form of probability tables on the whole energy spectrum. This study is intended in order to test and validate this approach in lattice physics and criticality-safety applications. The probability table method seems promising since it introduces an alternative computational way between the legacy continuous-energy representation and the multigroup method. In the first case, the amount of data invoked in continuous-energy Monte Carlo calculations can be very important and tend to slow down the overall computational time. In addition, this model preserves the quality of the physical laws present in the ENDF format. Due to its cheap computational cost, the multigroup Monte Carlo way is usually at the basis of production codes in criticality-safety studies. However, the use of a multigroup representation of the cross sections implies a preliminary calculation to take into account self-shielding effects for resonant isotopes. This is generally performed by deterministic lattice codes relying on the collision probability method. Using cross-section probability tables on the whole energy range permits to directly take into account self-shielding effects and can be employed in both lattice physics and criticality-safety calculations. Several aspects have been thoroughly studied: (1) The consistent computation of probability tables with a energy grid comprising only 295 or 361 groups. The CALENDF moment approach conducted to probability tables suitable for a Monte Carlo code. (2) The combination of the probability table sampling for the energy variable with the delta-tracking rejection technique for the space variable, and its impact on the overall efficiency of the proposed Monte Carlo algorithm. (3) The derivation of a model for taking into account anisotropic effects of the scattering reaction consistent with the subgroup method. In this study, we generalize the Discrete Angle Technique, already proposed for homogeneous, multigroup cross sections, to isotopic cross sections on the form of probability tables. In this technique, the angular density is discretized into probability tables. Similarly to the cross-section case, a moment approach is used to compute the probability tables for the scattering cosine. (4) The introduction of a leakage model based on the B1 fundamental mode approximation. Unlike deterministic lattice packages, most Monte Carlo-based lattice physics codes do not include leakage models. However the generation of homogenized and condensed group constants (cross sections, diffusion coefficients) require the critical flux. This project has involved the development of a program into the DRAGON framework, written in Fortran 2003 and wrapped with a driver in C, the GANLIB 5. Choosing Fortran 2003 has permitted the use of some modern features, such as the definition of objects and methods, data encapsulation and polymorphism. The validation of the proposed code has been performed by comparison with other numerical methods: (1) The continuous-energy Monte Carlo method of the SERPENT code. (2) The Collision Probability (CP) method and the discrete ordinates (SN) method of the DRAGON lattice code. (3) The multigroup Monte Carlo code MORET, coupled with the DRAGON code. Benchmarks used in this work are representative of some industrial configurations encountered in reactor and criticality-safety calculations: (1)Pressurized Water Reactors (PWR) cells and assemblies. (2) Canada-Deuterium Uranium Reactors (CANDU-6) clusters. (3) Critical experiments from the ICSBEP handbook (International Criticality Safety Benchmark Evaluation Program).

Martin, Nicolas

283

The Development of WARP - A Framework for Continuous Energy Monte Carlo Neutron Transport in General 3D Geometries on GPUs  

NASA Astrophysics Data System (ADS)

Graphics processing units, or GPUs, have gradually increased in computational power from the small, job-specific boards of the early 1990s to the programmable powerhouses of today. Compared to more common central processing units, or CPUs, GPUs have a higher aggregate memory bandwidth, much higher floating-point operations per second (FLOPS), and lower energy consumption per FLOP. Because one of the main obstacles in exascale computing is power consumption, many new supercomputing platforms are gaining much of their computational capacity by incorporating GPUs into their compute nodes. Since CPU-optimized parallel algorithms are not directly portable to GPU architectures (or at least not without losing substantial performance), transport codes need to be rewritten to execute efficiently on GPUs. Unless this is done, reactor simulations cannot take full advantage of these new supercomputers. WARP, which can stand for ``Weaving All the Random Particles,'' is a three-dimensional (3D) continuous energy Monte Carlo neutron transport code developed in this work as to efficiently implement a continuous energy Monte Carlo neutron transport algorithm on a GPU. WARP accelerates Monte Carlo simulations while preserving the benefits of using the Monte Carlo Method, namely, very few physical and geometrical simplifications. WARP is able to calculate multiplication factors, flux tallies, and fission source distributions for time-independent problems, and can run in both criticality or fixed source modes. WARP can transport neutrons in unrestricted arrangements of parallelepipeds, hexagonal prisms, cylinders, and spheres. WARP uses an event-based algorithm, but with some important differences. Moving data is expensive, so WARP uses a remapping vector of pointer/index pairs to direct GPU threads to the data they need to access. The remapping vector is sorted by reaction type after every transport iteration using a high-efficiency parallel radix sort, which serves to keep the reaction types as contiguous as possible and removes completed histories from the transport cycle. The sort reduces the amount of divergence in GPU ``thread blocks,'' keeps the SIMD units as full as possible, and eliminates using memory bandwidth to check if a neutron in the batch has been terminated or not. Using a remapping vector means the data access pattern is irregular, but this is mitigated by using large batch sizes where the GPU can effectively eliminate the high cost of irregular global memory access. WARP modifies the standard unionized energy grid implementation to reduce memory traffic. Instead of storing a matrix of pointers indexed by reaction type and energy, WARP stores three matrices. The first contains cross section values, the second contains pointers to angular distributions, and a third contains pointers to energy distributions. This linked list type of layout increases memory usage, but lowers the number of data loads that are needed to determine a reaction by eliminating a pointer load to find a cross section value. Optimized, high-performance GPU code libraries are also used by WARP wherever possible. The CUDA performance primitives (CUDPP) library is used to perform the parallel reductions, sorts and sums, the CURAND library is used to seed the linear congruential random number generators, and the OptiX ray tracing framework is used for geometry representation. OptiX is a highly-optimized library developed by NVIDIA that automatically builds hierarchical acceleration structures around user-input geometry so only surfaces along a ray line need to be queried in ray tracing. WARP also performs material and cell number queries with OptiX by using a point-in-polygon like algorithm. WARP has shown that GPUs are an effective platform for performing Monte Carlo neutron transport with continuous energy cross sections. Currently, WARP is the most detailed and feature-rich program in existence for performing continuous energy Monte Carlo neutron transport in general 3D geometries on GPUs, but compared to production codes like Serpent and MCNP, WARP ha

Bergmann, Ryan

284

First Super-Earth Atmosphere Analysed  

NASA Astrophysics Data System (ADS)

The atmosphere around a super-Earth exoplanet has been analysed for the first time by an international team of astronomers using ESO's Very Large Telescope. The planet, which is known as GJ 1214b, was studied as it passed in front of its parent star and some of the starlight passed through the planet's atmosphere. We now know that the atmosphere is either mostly water in the form of steam or is dominated by thick clouds or hazes. The results will appear in the 2 December 2010 issue of the journal Nature. The planet GJ 1214b was confirmed in 2009 using the HARPS instrument on ESO's 3.6-metre telescope in Chile (eso0950) [1]. Initial findings suggested that this planet had an atmosphere, which has now been confirmed and studied in detail by an international team of astronomers, led by Jacob Bean (Harvard-Smithsonian Center for Astrophysics), using the FORS instrument on ESO's Very Large Telescope. "This is the first super-Earth to have its atmosphere analysed. We've reached a real milestone on the road toward characterising these worlds," said Bean. GJ 1214b has a radius of about 2.6 times that of the Earth and is about 6.5 times as massive, putting it squarely into the class of exoplanets known as super-Earths. Its host star lies about 40 light-years from Earth in the constellation of Ophiuchus (the Serpent Bearer). It is a faint star [2], but it is also small, which means that the size of the planet is large compared to the stellar disc, making it relatively easy to study [3]. The planet travels across the disc of its parent star once every 38 hours as it orbits at a distance of only two million kilometres: about seventy times closer than the Earth orbits the Sun. To study the atmosphere, the team observed the light coming from the star as the planet passed in front of it [4]. During these transits, some of the starlight passes through the planet's atmosphere and, depending on the chemical composition and weather on the planet, specific wavelengths of light are absorbed. The team then compared these precise new measurements with what they would expect to see for several possible atmospheric compositions. Before the new observations, astronomers had suggested three possible atmospheres for GJ 1214b. The first was the intriguing possibility that the planet was shrouded by water, which, given the close proximity to the star, would be in the form of steam. The second possibility was that this is a rocky world with an atmosphere consisting mostly of hydrogen, but with high clouds or hazes obscuring the view. The third option was that this exoplanet was like a mini-Neptune, with a small rocky core and a deep hydrogen-rich atmosphere. The new measurements do not show the telltale signs of hydrogen and hence rule out the third option. Therefore, the atmosphere is either rich in steam, or it is blanketed by clouds or hazes, similar to those seen in the atmospheres of Venus and Titan in our Solar System, which hide the signature of hydrogen.. "Although we can't yet say exactly what that atmosphere is made of, it is an exciting step forward to be able to narrow down the options for such a distant world to either steamy or hazy," says Bean. "Follow-up observations in longer wavelength infrared light are now needed to determine which of these atmospheres exists on GJ 1214b." Notes [1] The number of confirmed exoplanets reached 500 on 19 November 2010. Since then, more exoplanets have been confirmed. For the latest count, please visit: http://exoplanet.eu/catalog.php [2] If GJ 1214 were seen at the same distance from us as our Sun, it would appear 300 times fainter. [3] Because the star GJ1214 itself is quite faint - more than 100 times fainter in visible light than the host stars of the two most widely studied hot Jupiter exoplanets - the large collecting area of the Very Large Telescope was critical for acquiring enough signal for these measurements. [4] GJ 1214b's atmospheric composition was studied using the FORS instrument on the Very Large Telescope, which can perform very sensitive spectroscopy of

2010-12-01