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1

Vacunas contra los virus del papiloma humano  

Cancer.gov

Hoja informativa acerca de las vacunas contra los virus del papiloma humano (VPH) para prevenir infecciones con ciertos tipos de VPH, los cuales son la causa principal del cáncer de cuello del útero o cérvix.

2

Pruebas de Papanicolaou y del virus del papiloma humano (VPH)  

Cancer.gov

Hoja informativa que describe los exámenes selectivos de detección del cáncer de cérvix, los cuales incluyen la prueba de Papanicolaou y la prueba de los virus del papiloma humano. La hoja informativa incluye también información acerca de las pautas de exámenes de detección del cáncer de cérvix.

3

Polimorfismos genéticos de aislamientos del género Malassezia obtenidos en Colombia de pacientes con lesión dermatológica y sin ella  

Microsoft Academic Search

Introducción. Las especies del género Malassezia se consideran levaduras oportunistas emergentes de gran importancia. Han sido asociadas a diferentes patologías dermatológicas y sistémicas de las cuales se aislan una o más especies de este género. El papel de estas levaduras en las enfermedades dermatológicas no se ha aclarado completamente, ya que la Malassezia spp. pertenece a la flora normal de

Adriana M. Celis; Maria Caridad Cepero de García

4

Datura GENUS WEEDS AS AN EPIDEMIOLOGICAL FACTOR OF Alfalfa mosaic virus (AMV), Cucumber mosaic virus (CMV), AND Potato virus Y (PVY) ON SOLANACEUS CROPS Malezas del género Datura como factor epidemiológico del Virus del mosaico de la alfalfa (AMV), Virus del mosaico del pepino (CMV) y Virus Y de la papa (PVY) en Solanáceas cultivadas  

Microsoft Academic Search

A B S T R A C T Plant samples of jimsonweed (Datura stramonium L.) and thornapple (D. ferox L.) were collected to determine the presence of Cucumber mosaic virus (CMV), Alfalfa mosaic virus (AMV), and Potato virus Y (PVY) in Santiago, Chile (33º34' S lat, 70º38' W long, altitude 625 m.o.s.l.), using double stranded RNA (dsRNA) analysis and ELISA.

Juan Ormeño; Paulina Sepúlveda; Ricardo Rojas; Jaime E. Araya

5

Chino del tomate virus:Relationships to Other Begomoviruses and Identification of A-Component Variants that Affect Symptom Expression.  

PubMed

Phylogenetic and distance analyses place Chino del tomate virus (CdTV) in the New World clade of begomoviruses and indicate that CdTV and Tomato leaf crumple virus (TLCrV) are closely related strains of the same virus. One cloned CdTV A component (pCdTV-H6), when inoculated to tomato with the B component (pCdTV-B52), produced mild symptoms and low DNA titers. Another cloned CdTV A component (pCdTV-H8), when coinoculated to tomato with the B component, produced moderate leaf curling and veinal chlorosis similar to that of TLCrV. Coinoculation of both CdTV A components and the B component to tomato produced wild-type chino del tomate (CdT) disease symptoms consisting of severe leaf curling, veinal and interveinal chlorosis, and stunting. The two CdTV A components were nearly identical, except at nucleotide positions 1,722 and 2,324. The polymorphism at nucleotide 1,722 resulted in a change at Rep amino acid 261. The second polymorphism at nucleotide 2,324 resulted in changes at Rep amino acid 60 and AC4 amino acid 10. Two chimeric A components constructed by reciprocal exchange of a fragment bearing the polymorphic site at nucleotide 1,722 were evaluated for symptom phenotype. One chimeric A component (pCdTV-H86) produced wild-type CdT symptoms when coinoculated to tomato with the B component. The reciprocal chimeric A component (pCdTV-H68), when coin-oculated to tomato with the B component, also produced severe leaf curling, veinal chlorosis, and stunting. However, pCdTV-H68 induced less obvious interveinal chlorosis than wild-type or pCdTV-H86. Examination of A component genotypes recovered from tomato coinoculated with pCdTV-H6 and pCdTV-H8 indicated that recombination occurred to produce a genotype identical to pCdTV-H86. These results indicate that subtle genotypic variation has significant effects on symptom expression and may explain phenotypic differences observed among isolates and cloned DNAs of CdTV and TLCrV. PMID:18944562

Brown, J K; Ostrow, K M; Idris, A M; Stenger, D C

2000-05-01

6

Detección del Virus Mosaico Amarillo de la Calabaza Zucchini (ZYMV) y su Coinfección con otros Virus en Cucurbitáceas Cultivadas y Plantas Silvestres en el Valle del Fuerte, Sinaloa, México  

Microsoft Academic Search

Viral diseases are the main limiting factor for cucurbit production in El Fuerte Valley, Sinaloa, Mexico. The objective of this study was to detect Zucchini yellows mosaic virus (ZYWV), Watermelon mosaic virus (WMV), Papaya ring spot virus (PRSV-W), and Cucumber mosaic virus (CMV) using ELISA and RT-PCR procedures. ZYMV and the mixture ZYMV + PRSV-W predominated during the month of

Rubén Félix-Gastélum; Marco Antonio Magallanes-Tapia; Jesús Méndez-Lozano; Hervé Huet; José Ángel Trigueros-Salmerón; Rosa María Longoria-Espinoza

2007-01-01

7

Cache Valley Virus in the Del Mar VA Peninsula. Iii. Serologic Evidence for Natural Infection of Dairy Cattle.  

National Technical Information Service (NTIS)

Preliminary observations indicating that cattle resident in coastal Maryland and Virginia are natural hosts for Cache Valley virus were confirmed by extended serologic surveys. That virus-neutralizing substances in cattle were indeed antibody was establis...

T. M. Yuill W. S. Gochenour F. R. Lucas M. J. Collins E. L. Buescher

1969-01-01

8

Virus-like attachment sites and plastic CpG islands:landmarks of diversity in plant Del retrotransposons.  

PubMed

Full-length Del elements from ten angiosperm genomes, 5 monocot and 5 dicot, were retrieved and putative attachment (att) sites were identified. In the 2432 Del elements, two types of U5 att sites and a single conserved type of U3 att site were identified. Retroviral att sites confer specificity to the integration process, different att sites types therefore implies lineage specificity. While some features are common to all Del elements, CpG island patterns within the LTRs were particular to lineage specific clusters. All eudicot copies grouped into one single clade while the monocots harbour a more diverse collection of elements. Furthermore, full-length Del elements and truncated copies were unevenly distributed amongst chromosomes. Elements of Del lineage are organized in plants into three clusters and each cluster is composed of elements with distinct LTR features. Our results suggest that the Del lineage efficiently amplified in the monocots and that one branch is probably a newly emerging sub-lineage. Finally, sequences in all groups are under purifying selection. These results show the LTR region is dynamic and important in the evolution of LTR-retrotransposons, we speculate that it is a trigger for retrotransposon diversification. PMID:24849372

Cruz, Guilherme M Q; Metcalfe, Cushla J; de Setta, Nathalia; Cruz, Edgar A O; Vieira, Andréia Prata; Medina, Rosario; Van Sluys, Marie-Anne

2014-01-01

9

Virus-Like Attachment Sites and Plastic CpG Islands: Landmarks of Diversity in Plant Del Retrotransposons  

PubMed Central

Full-length Del elements from ten angiosperm genomes, 5 monocot and 5 dicot, were retrieved and putative attachment (att) sites were identified. In the 2432 Del elements, two types of U5 att sites and a single conserved type of U3 att site were identified. Retroviral att sites confer specificity to the integration process, different att sites types therefore implies lineage specificity. While some features are common to all Del elements, CpG island patterns within the LTRs were particular to lineage specific clusters. All eudicot copies grouped into one single clade while the monocots harbour a more diverse collection of elements. Furthermore, full-length Del elements and truncated copies were unevenly distributed amongst chromosomes. Elements of Del lineage are organized in plants into three clusters and each cluster is composed of elements with distinct LTR features. Our results suggest that the Del lineage efficiently amplified in the monocots and that one branch is probably a newly emerging sub-lineage. Finally, sequences in all groups are under purifying selection. These results show the LTR region is dynamic and important in the evolution of LTR-retrotransposons, we speculate that it is a trigger for retrotransposon diversification.

de Setta, Nathalia; Cruz, Edgar A. O.; Vieira, Andreia Prata; Medina, Rosario; Van Sluys, Marie-Anne

2014-01-01

10

West Nile Virus: Symptoms and Treatment  

MedlinePLUS

... Education Public Service Videos West Nile Virus in Spanish Preguntas frecuentes: Preguntas generales sobre el virus del Nilo Occidental en Español (Spanish) Síntomas y tratamiento en Español (Spanish) Prevención y ...

11

West Nile Virus: Prevention and Control  

MedlinePLUS

... Education Public Service Videos West Nile Virus in Spanish Preguntas frecuentes: Preguntas generales sobre el virus del Nilo Occidental en Español (Spanish) Síntomas y tratamiento en Español (Spanish) Prevención y ...

12

FAQ: General Questions about West Nile Virus  

MedlinePLUS

... Education Public Service Videos West Nile Virus in Spanish Preguntas frecuentes: Preguntas generales sobre el virus del Nilo Occidental en Español (Spanish) Síntomas y tratamiento en Español (Spanish) Prevención y ...

13

Identificación del antígeno del virus de la fiebre porcina clásica en excretas porcinas sólidas y líquidas en una granja del estado de Guanajuato, México Identification of Classical Swine Fever virus antigen in solid and liquid swine faeces from a Guanajuato State farm, Mexico  

Microsoft Academic Search

The purpose of this study was the detection of Classical Swine Fever virus (CSFv) in organic waste matter. A total of 40 samples from collection basin sludge, solid faeces and separated liquid phases from eight farms with faeces treatment systems based on a liquid and solids separation process in Central Mexico, were evaluated. All the samples were tested by direct

Roberto Martínez-Gambaa

14

Foamy Viruses  

Microsoft Academic Search

Summary Foamy viruses share complex genome organization with lentiviruses and certain oncoviruses. The open reading frame 3’ of env encodes a transcriptional transactivator. Distinct responsive sequences were identified in the long terminal repeats (LTRs) of simian (SFV-1 and SFV-3) and human foamy viruses (HFV). Transactivation of heterologous LTRs was described including those of simian and human immunodeficiency viruses. Foamy viruses

D. Neumann-Haefelin; U. Fleps; R. Renne; M. Schweizer

1993-01-01

15

Oncolytic viruses  

Microsoft Academic Search

Although the cytotoxic effects of viruses are usually viewed in terms of pathogenicity, it is possible to harness this activity for therapeutic purposes. Viral genomes are highly versatile, and can be modified to direct their cytotoxicity towards cancer cells. These viruses are known as oncolytic viruses. How are viruses engineered to become tumour specific, and can they be used to

E. Antonio Chiocca

2002-01-01

16

Boletín del Instituto Nacional del Cáncer  

Cancer.gov

No se puede negar que vivimos en una comunidad global, en la que los eventos de una ciudad o país pueden tener graves consecuencias para los residentes de otra ciudad o país a miles de kilómetros de distancia. Ya sea la pandemia del virus H1N1, los recientes disturbios en Irán o la recesión económica mundial, es evidente que esta interconectividad trae consigo retos importantes. Pero también puede crear oportunidades sin precedentes, en particular aquellas que podrían mejorar sustancialmente la salud pública.

17

CARACTERIZACIÓN DE UNA VARIANTE DEL VIRUS MOSAICO DEL PEPINO (CMV) ASOCIADA CON LOS SÍNTOMAS DE MOTEADO AMARILLO DE LA AZUCENA (Hippeastrum×hybridum Leopoldii) EN MÉXICO CHARACTERIZATION OF A CUCUMBER MOSAIC VIRUS (CMV) STRAIN ASSOCIATED WITH YELLOW MOTTLE SYMPTOMS OF AMARYLLIS (Hippeastrum×hybridum Leopoldii) IN MÉXICO  

Microsoft Academic Search

A strain of Cucumber Mosaic Virus (CMV, Cucumovirus), belonging to the subgroup CMV-Ib, was characterized as the causal agent of yellow mottle diseases in Amaryllis (Hippeastrum× hybridum Leopoldii) from commercial nurseries and home gardens in the State of México. The characterization was performed by indicator host range, morphology and size of viral particle under an electron microscope and determination of

Cleopatra Gutiérrez-Villegas; Roberto Ruiz-Medrano; Elías Piedra-Ibarra; Rodolfo De La Torre-Almaráz; Carretera México-Texcoco

2004-01-01

18

Virus maturation.  

PubMed

The formation of infectious virus particles is a highly complex process involving a series of sophisticated molecular events. In most cases, the assembly of virus structural elements results in the formation of immature virus particles unable to initiate a productive infection. Accordingly, for most viruses the final stage of the assembly pathway entails a set of structural transitions and/or biochemical modifications that transform inert precursor particles into fully infectious agents. In this chapter, we review the most relevant maturation mechanisms involved in the generation of infectious virions for a wide variety of viruses. PMID:23737059

Delgui, Laura R; Rodríguez, José F

2013-01-01

19

Virus Maturation  

PubMed Central

We examined virus maturation of selected non-enveloped and enveloped ssRNA viruses; retroviruses; bacteriophages and herpes virus. Processes associated with maturation in the RNA viruses range from subtle (noda and picornaviruses) to dramatic (tetraviruses and togaviruses). The elaborate assembly and maturation pathway of HIV is discussed in contrast to the less sophisticated but highly efficient processes associated with togaviruses. Bacteriophage assembly and maturation are discussed in general terms with specific examples chosen for emphasis. Finally the herpes viruses are compared with bacteriophages. The data support divergent evolution of noda, picorna and tetraviruses from a common ancestor and divergent evolution of alpha and flaviviruses from a common ancestor. Likewise, bacteriophages and herpes viruses almost certainly share a common ancestor in their evolution. Comparing all the viruses, we conclude that maturation is a convergent process that is required to solve conflicting requirements in biological dynamics and function.

Veesler, David; Johnson, John E.

2013-01-01

20

CHLORELLA VIRUSES  

PubMed Central

Chlorella viruses or chloroviruses are large, icosahedral, plaque?forming, double?stranded?DNA—containing viruses that replicate in certain strains of the unicellular green alga Chlorella. DNA sequence analysis of the 330?kbp genome of Paramecium bursaria chlorella virus 1 (PBCV?1), the prototype of this virus family (Phycodnaviridae), predict ?366 protein?encoding genes and 11 tRNA genes. The predicted gene products of ?50% of these genes resemble proteins of known function, including many that are completely unexpected for a virus. In addition, the chlorella viruses have several features and encode many gene products that distinguish them from most viruses. These products include: (1) multiple DNA methyltransferases and DNA site?specific endonucleases, (2) the enzymes required to glycosylate their proteins and synthesize polysaccharides such as hyaluronan and chitin, (3) a virus?encoded K+ channel (called Kcv) located in the internal membrane of the virions, (4) a SET domain containing protein (referred to as vSET) that dimethylates Lys27 in histone 3, and (5) PBCV?1 has three types of introns; a self?splicing intron, a spliceosomal processed intron, and a small tRNA intron. Accumulating evidence indicates that the chlorella viruses have a very long evolutionary history. This review mainly deals with research on the virion structure, genome rearrangements, gene expression, cell wall degradation, polysaccharide synthesis, and evolution of PBCV?1 as well as other related viruses.

Yamada, Takashi; Onimatsu, Hideki; Van Etten, James L.

2007-01-01

21

Chlorella viruses.  

PubMed

Chlorella viruses or chloroviruses are large, icosahedral, plaque-forming, double-stranded-DNA-containing viruses that replicate in certain strains of the unicellular green alga Chlorella. DNA sequence analysis of the 330-kbp genome of Paramecium bursaria chlorella virus 1 (PBCV-1), the prototype of this virus family (Phycodnaviridae), predict approximately 366 protein-encoding genes and 11 tRNA genes. The predicted gene products of approximately 50% of these genes resemble proteins of known function, including many that are completely unexpected for a virus. In addition, the chlorella viruses have several features and encode many gene products that distinguish them from most viruses. These products include: (1) multiple DNA methyltransferases and DNA site-specific endonucleases, (2) the enzymes required to glycosylate their proteins and synthesize polysaccharides such as hyaluronan and chitin, (3) a virus-encoded K(+) channel (called Kcv) located in the internal membrane of the virions, (4) a SET domain containing protein (referred to as vSET) that dimethylates Lys27 in histone 3, and (5) PBCV-1 has three types of introns; a self-splicing intron, a spliceosomal processed intron, and a small tRNA intron. Accumulating evidence indicates that the chlorella viruses have a very long evolutionary history. This review mainly deals with research on the virion structure, genome rearrangements, gene expression, cell wall degradation, polysaccharide synthesis, and evolution of PBCV-1 as well as other related viruses. PMID:16877063

Yamada, Takashi; Onimatsu, Hideki; Van Etten, James L

2006-01-01

22

Phytophthora viruses.  

PubMed

Phytophthora sp. is a genus in the oomycetes, which are similar to filamentous fungi in morphology and habitat, but phylogenetically more closely related to brown algae and diatoms and fall in the kingdom Stramenopila. In the past few years, several viruses have been characterized in Phytophthora species, including four viruses from Phytophthora infestans, the late blight pathogen, and an endornavirus from an unnamed Phytophthora species from Douglas fir. Studies on Phytophthora viruses have revealed several interesting systems. Phytophthora infestans RNA virus 1 (PiRV-1) and PiRV-2 are likely the first members of two new virus families; studies on PiRV-3 support the establishment of a new virus genus that is not affiliated with established virus families; PiRV-4 is a member of Narnaviridae, most likely in the genus Narnavirus; and Phytophthora endornavirus 1 (PEV1) was the first nonplant endornavirus at the time of reporting. Viral capsids have not been found in any of the above-mentioned viruses. PiRV-1 demonstrated a unique genome organization that requires further examination, and PiRV-2 may have played a role in late blight resurgence in 1980s-1990s. PMID:23498912

Cai, Guohong; Hillman, Bradley I

2013-01-01

23

Actividades enzimáticas en aislamientos bacterianos de tractos digestivos de larvas y del contenido de pupas de Automeris zugana y Rothschildia lebeau (Lepidoptera: Saturniidae)  

Microsoft Academic Search

Enzymatic activities of bacteria isolated from the digestive tract of caterpillars and the pupal content of Automeris zugana and Rothschildia lebeau (Lepidoptera: Saturniidae). The enzymatic activities of bacteria isolated from the digestive tracts of caterpillars and the pupal contents of Automeris zugana and Rothschildia lebeau was studied. This digestive tract represents an extreme microenvironment due to its high pH and

Adrián Pinto-Tomás; Lorena Uribe-Lorío; John Blanco; Gustavo Fontecha; César Rodríguez; Marielos Mora; Daniel Janzen; Felipe Chavarría; Joel Díaz; Ana Sittenfeld

2007-01-01

24

Emerging Viruses  

NSDL National Science Digital Library

Emerging viruses are those "whose incidence in humans has increased in the past 2 decades or threatens to increase in the near future." This week's Topic in Depth focuses on sites related to viruses, particularly those that are considered "emerging."The first site (1) is an essay by Alison Jacobson of the University of Capetown that discusses some emerging and potentially emerging viruses, along with factors that contribute to the threat. From a US government interagency working group, the second report (2) focuses on the responses to infectious disease outbreaks, including drugs, vaccines, and government response. A World Health Organization site (3) highlights recent reports of infectious disease, archived by date and by disease. This ThinkQuest site (4) gives a basic introduction to viruses and how they cause infections. An online virology tutorial (5) by Ed Rybicki of the University of Cape Town serves as a lesson on the basics of virology for a more advanced student. The next two sites focus on the specifics of selected viruses. From the Institute for Molecular Virology (6) comes a resource on Marburg and Ebola viruses, and from the National Biological Information Infrastructure (7) is a site on West Nile Virus. The last resource (8) is a scholarly journal from the Centers for Disease Control that presents some of the latest scientific research on emerging diseases.

Lee, Amy.

2002-01-01

25

Computer viruses  

NASA Technical Reports Server (NTRS)

The worm, Trojan horse, bacterium, and virus are destructive programs that attack information stored in a computer's memory. Virus programs, which propagate by incorporating copies of themselves into other programs, are a growing menace in the late-1980s world of unprotected, networked workstations and personal computers. Limited immunity is offered by memory protection hardware, digitally authenticated object programs,and antibody programs that kill specific viruses. Additional immunity can be gained from the practice of digital hygiene, primarily the refusal to use software from untrusted sources. Full immunity requires attention in a social dimension, the accountability of programmers.

Denning, Peter J.

1988-01-01

26

Tetherin inhibits prototypic foamy virus release  

PubMed Central

Background Tetherin (also known as BST-2, CD317, and HM1.24) is an interferon- induced protein that blocks the release of a variety of enveloped viruses, such as retroviruses, filoviruses and herpesviruses. However, the relationship between tetherin and foamy viruses has not been clearly demonstrated. Results In this study, we found that tetherin of human, simian, bovine or canine origin inhibits the production of infectious prototypic foamy virus (PFV). The inhibition of PFV by human tetherin is counteracted by human immunodeficiency virus type 1 (HIV-1) Vpu. Furthermore, we generated human tetherin transmembrane domain deletion mutant (delTM), glycosyl phosphatidylinositol (GPI) anchor deletion mutant (delGPI), and dimerization and glycosylation deficient mutants. Compared with wild type tetherin, the delTM and delGPI mutants only moderately inhibited PFV production. In contrast, the dimerization and glycosylation deficient mutants inhibit PFV production as efficiently as the wild type tetherin. Conclusions These results demonstrate that tetherin inhibits the release and infectivity of PFV, and this inhibition is antagonized by HIV-1 Vpu. Both the transmembrane domain and the GPI anchor of tetherin are important for the inhibition of PFV, whereas the dimerization and the glycosylation of tetherin are dispensable.

2011-01-01

27

Influenza A Virus Induces an Immediate Cytotoxic Activity in All Major Subsets of Peripheral Blood Mononuclear Cells  

PubMed Central

Background A replication defective influenza A vaccine virus (delNS1 virus) was developed. Its attenuation is due to potent stimulation of the innate immune system by the virus. Since the innate immune system can also target cancer cells, we reasoned that delNS1 virus induced immune-stimulation should also lead to the induction of innate cytotoxic effects towards cancer cells. Methodology/Principal Findings Peripheral blood mononuclear cells (PBMCs), isolated CD56+, CD3+, CD14+ and CD19+ subsets and different combinations of the above subsets were stimulated by delNS1, wild type (wt) virus or heat inactivated virus and co-cultured with tumor cell lines in the presence or absence of antibodies against the interferon system. Stimulation of PBMCs by the delNS1 virus effectively induced cytotoxicity against different cancer cell lines. Surprisingly, virus induced cytotoxicity was exerted by all major subtypes of PBMCs including CD56+, CD3+, CD14+ and CD19+ cells. Virus induced cytotoxicity in CD3+, CD14+ and CD19+ cells was dependent on virus replication, whereas virus induced cytotoxicity in CD56+ cells was only dependent on the binding of the virus. Virus induced cytotoxicity of isolated cell cultures of CD14+, CD19+ or CD56+ cells could be partially blocked by antibodies against type I and type II (IFN) interferon. In contrast, virus induced cytotoxicity in the complete PBMC preparation could not be inhibited by blocking type I or type II IFN, indicating a redundant system of activation in whole blood. Conclusions/Significance Our data suggest that apart from their well known specialized functions all main subsets of peripheral blood cells also initially exert a cytotoxic effect upon virus stimulation. This closely links the innate immune system to the adaptive immune response and renders delNS1 virus a potential therapeutic tool for viro-immunotherapy of cancer.

Baumann, Suzann; Kuznetsova, Irina; Spittler, Andreas; Bergmann, Michael

2009-01-01

28

Passatempo Virus, a Vaccinia Virus Strain, Brazil  

PubMed Central

Passatempo virus was isolated during a zoonotic outbreak. Biologic features and molecular characterization of hemagglutinin, thymidine kinase, and vaccinia growth factor genes suggested a vaccinia virus infection, which strengthens the idea of the reemergence and circulation of vaccinia virus in Brazil. Molecular polymorphisms indicated that Passatempo virus is a different isolate.

Leite, Juliana A.; Drumond, Betania P.; Trindade, Giliane S.; Lobato, Zelia I.P.; da Fonseca, Flavio G.; dos Santos, Joao R.; Madureira, Marieta C.; Guedes, Maria I.M.C.; Ferreira, Jaqueline M.S.; Bonjardim, Claudio A.; Ferreira, Paulo C.P.

2005-01-01

29

The Geometry of Viruses.  

ERIC Educational Resources Information Center

Presented is an activity in which students make models of viruses, which allows them to visualize the shape of these microorganisms. Included are some background on viruses, the biology and geometry of viruses, directions for building viruses, a comparison of cells and viruses, and questions for students. (KR)

Case, Christine L.

1991-01-01

30

Constructing Computer Virus Phylogenies  

Microsoft Academic Search

There has been much recent algorithmic work on the problem of reconstructing the evolutionary history of biological species. Computer virus specialists are interested in finding the evolutionary history of computer viruses—a virus is often written using code fragments from one or more other viruses, which are its immediate ancestors. A phylogeny for a collection of computer viruses is a directed

Leslie Ann Goldberg; Paul W. Goldberg; Cynthia A. Phillips; Gregory B. Sorkin

1998-01-01

31

Análisis descriptivo del tamaño relativo del gasto del gobierno chileno  

Microsoft Academic Search

En este trabajo se examina el tamaño relativo del Gobierno chileno a través de una comparación internacional con valores equivalentes de otros países. Adicionalmente hay un análisis similar para dos componentes importantes del gasto público: educación y salud. El gasto del Gobierno de Chile, valor en torno del 20% (PIB), está junto al tercio inferior de países que poseen un

Eduardo Engel; Patricio Meller; Claudio Bravo

1998-01-01

32

Constructing computer virus phylogenies.  

National Technical Information Service (NTIS)

There has been much recent algorithmic work on the problem of reconstructing the evolutionary history of biological species. Computer virus specialists are interested in finding the evolutionary history of computer viruses--a virus is often written using ...

L. A. Goldberg P. W. Goldberg C. A. Phillips G. B. Sorkin

1996-01-01

33

Computer Viruses: An Overview.  

ERIC Educational Resources Information Center

Discusses the early history and current proliferation of computer viruses that occur on Macintosh and DOS personal computers, mentions virus detection programs, and offers suggestions for how libraries can protect themselves and their users from damage by computer viruses. (LRW)

Marmion, Dan

1990-01-01

34

Virus Movement Maintains Local Virus Population Diversity  

SciTech Connect

Viruses are the largest reservoir of genetic material on the planet, yet little is known about the population dynamics of any virus within its natural environment. Over a 2-year period, we monitored the diversity of two archaeal viruses found in hot springs within Yellowstone National Park (YNP). Both temporal phylogeny and neutral biodiversity models reveal that virus diversity in these local environments is not being maintained by mutation but rather by high rates of immigration from a globally distributed metacommunity. These results indicate that geographically isolated hot springs are readily able to exchange viruses. The importance of virus movement is supported by the detection of virus particles in air samples collected over YNP hot springs and by their detection in metacommunity sequencing projects conducted in the Sargasso Sea. Rapid rates of virus movement are not expected to be unique to these archaeal viruses but rather a common feature among virus metacommunities. The finding that virus immigration rather than mutation can dominate community structure has significant implications for understanding virus circulation and the role that viruses play in ecology and evolution by providing a reservoir of mobile genetic material.

J. Snyder; B. Wiedenheft; M. Lavin; F. Roberto; J. Spuhler; A. Ortmann; T. Douglas; M. Young

2007-11-01

35

Virus movement maintains local virus population diversity  

PubMed Central

Viruses are the largest reservoir of genetic material on the planet, yet little is known about the population dynamics of any virus within its natural environment. Over a 2-year period, we monitored the diversity of two archaeal viruses found in hot springs within Yellowstone National Park (YNP). Both temporal phylogeny and neutral biodiversity models reveal that virus diversity in these local environments is not being maintained by mutation but rather by high rates of immigration from a globally distributed metacommunity. These results indicate that geographically isolated hot springs are readily able to exchange viruses. The importance of virus movement is supported by the detection of virus particles in air samples collected over YNP hot springs and by their detection in metacommunity sequencing projects conducted in the Sargasso Sea. Rapid rates of virus movement are not expected to be unique to these archaeal viruses but rather a common feature among virus metacommunities. The finding that virus immigration rather than mutation can dominate community structure has significant implications for understanding virus circulation and the role that viruses play in ecology and evolution by providing a reservoir of mobile genetic material.

Snyder, Jamie C.; Wiedenheft, Blake; Lavin, Matthew; Roberto, Francisco F.; Spuhler, Josh; Ortmann, Alice C.; Douglas, Trevor; Young, Mark

2007-01-01

36

Live Attenuated Herpes Simplex Virus 2 Glycoprotein E Deletion Mutant as a Vaccine Candidate Defective in Neuronal Spread  

PubMed Central

A herpes simplex virus 2 (HSV-2) glycoprotein E deletion mutant (gE2-del virus) was evaluated as a replication-competent, attenuated live virus vaccine candidate. The gE2-del virus is defective in epithelial cell-to-axon spread and in anterograde transport from the neuron cell body to the axon terminus. In BALB/c and SCID mice, the gE2-del virus caused no death or disease after vaginal, intravascular, or intramuscular inoculation and was 5 orders of magnitude less virulent than wild-type virus when inoculated directly into the brain. No infectious gE2-del virus was recovered from dorsal root ganglia (DRG) after multiple routes of inoculation; however, gE2-del DNA was detected by PCR in lumbosacral DRG at a low copy number in some mice. Importantly, no recurrent vaginal shedding of gE2-del DNA was detected in immunized guinea pigs. Intramuscular immunization outperformed subcutaneous immunization in all parameters evaluated, although individual differences were not significant, and two intramuscular immunizations were more protective than one. Immunized animals had reduced vaginal disease, vaginal titers, DRG infection, recurrent genital lesions, and recurrent vaginal shedding of HSV-2 DNA; however, protection was incomplete. A combined modality immunization using live virus and HSV-2 glycoprotein C and D subunit antigens in guinea pigs did not totally eliminate recurrent lesions or recurrent vaginal shedding of HSV-2 DNA. The gE2-del virus used as an immunotherapeutic vaccine in previously HSV-2-infected guinea pigs greatly reduced the frequency of recurrent genital lesions. Therefore, the gE2-del virus is safe, other than when injected at high titer into the brain, and is efficacious as a prophylactic and immunotherapeutic vaccine.

Zumbrun, Elizabeth E.; Si, Huaxin; Wang, Fushan; Shaw, Carolyn E.; Cai, Michael; Lubinski, John M.; Barrett, Shana M.; Balliet, John W.; Flynn, Jessica A.; Casimiro, Danilo R.; Bryan, Janine T.; Friedman, Harvey M.

2012-01-01

37

Salmonid viruses: Infectious pancreatic necrosis virus  

Microsoft Academic Search

Summary Epizootics occurred among young trout in France, and the behavior and symptoms suggested infectious pancreatic necrosis (IPN) virus. Specimens preserved in glycerol were sent to the U.S.A. for virological examination. Virus was isolated from four of five lots, but neutralization with antiserum against ATCC VR299 strain IPN virus was incomplete. Electron microscopy, bioassay, histopathology, and serology were used to

Ken Wolf; M. C. Quimby

1971-01-01

38

The Tobacco Mosaic Virus.  

ERIC Educational Resources Information Center

Explains how the tobacco mosaic virus can be used to study virology. Presents facts about the virus, procedures to handle the virus in the laboratory, and four laboratory exercises involving the viruses' survival under inactivating conditions, dilution end point, filterability, and microscopy. (MDH)

Sulzinski, Michael A.

1992-01-01

39

Virus entry by macropinocytosis  

Microsoft Academic Search

As obligatory intracellular parasites, viruses rely on host-cell functions for most aspects of their replication cycle. This is born out during entry, when most viruses that infect vertebrate and insect cells exploit the endocytic activities of the host cell to move into the cytoplasm. Viruses belonging to vaccinia, adeno, picorna and other virus families have been reported to take advantage

Jason Mercer; Ari Helenius

2009-01-01

40

Atlas del Genoma del Cáncer  

Cancer.gov

Es posible que haya más de 200 tipos diferentes de cáncer y muchos subtipos más, cada uno de estos causado por errores en el ADN que desencadenan el crecimiento descontrolado de las células. La identificación de los cambios en el conjunto completo de ADN de cada tipo de cáncer, su genoma, y el entendimiento de cómo interactúan dichos cambios para impulsar el proceso de la enfermedad sentarán las bases de una era individualizada de tratamiento del cáncer.

41

Asociación entre el virus XMRV y enfermedades humanas: preguntas y respuestas  

Cancer.gov

El XMRV es un retrovirus del que se informó por primera vez en 2006 como una causa potencial del cáncer de próstata. Está estrechamente relacionado con los virus de leucemia murina, los cuales causan una amplia variedad de cánceres así como enfermedades inmunológicas y neurológicas en ratones.

42

Identification of infectious bursal disease virus quasispecies in commercial vaccines and field isolates of this double-stranded RNA virus.  

PubMed

Quasispecies of infectious bursal disease virus (IBDV) vaccine and wild-type strains were identified using real-time RT-PCR at a region of the viral genome known for sequence variability. The LightCycler (Idaho Technology, Inc.) and hybridization probe system (Roche, Molecular Biochemicals) were used. An anchor probe labeled with LightCycler Red 640 and mutation probe labeled with fluorescein were designed using the Del-E IBDV sequence. The sequence of the mutation probe included nucleotides in the hydrophilic B region of VP2 that are important to a viral neutralizing epitope. This Del-E mutation probe was allowed to hybridize to the RT-PCR products following amplification and its temperature of dissociation (T(m)) from each viral template was determined using the LightCycler melting peak analysis. The observed T(m) for the Del-E mutation probe with its homologous virus, Del-E, was usually 65.5 degrees C but ranged from 65 to 66.4 degrees C. Peak melting temperatures for the test viruses were inversely proportional to the number of mutations observed between the Del-E mutation probe and target virus sequence. All the IBDV vaccine strains tested and all but two of the wild-type strains exhibited more than one melting peak, indicating that genetic subpopulations or quasispecies of the viruses were present in the samples. Since the mutation probe was located at a site which encodes a neutralizing epitope of the virus, it is possible that the genetic differences observed are translated into antigenic changes in this VP2 epitope and contribute to antigenic diversity in the quasispecies cloud. PMID:12490408

Jackwood, Daral J; Sommer, Susan E

2002-12-01

43

Instantánea del cáncer infantil  

Cancer.gov

Información sobre la incidencia y mortalidad del cáncer en los niños, tendencias en el financiamiento del NCI para la investigación del cáncer infantil; así como ejemplos de actividades y adelantos en la investigación relevantes para esta población.

44

Viruses in the sea.  

PubMed

Viruses exist wherever life is found. They are a major cause of mortality, a driver of global geochemical cycles and a reservoir of the greatest genetic diversity on Earth. In the oceans, viruses probably infect all living things, from bacteria to whales. They affect the form of available nutrients and the termination of algal blooms. Viruses can move between marine and terrestrial reservoirs, raising the spectre of emerging pathogens. Our understanding of the effect of viruses on global systems and processes continues to unfold, overthrowing the idea that viruses and virus-mediated processes are sidebars to global processes. PMID:16163346

Suttle, Curtis A

2005-09-15

45

A Genetically Engineered Waterfowl Influenza Virus with a Deletion in the Stalk of the Neuraminidase Has Increased Virulence for Chickens?  

PubMed Central

A deletion of about 20 amino acids in the stalk of the neuraminidase (NA) is frequently detected upon transmission of influenza A viruses from waterfowl to domestic poultry. Using reverse genetics, a recombinant virus derived from a wild duck influenza virus isolate, A/Mallard/Marquenterre/Z237/83 (MZ), and an NA stalk deletion variant (MZ-delNA) were produced. Compared to the wild type, the MZ-delNA virus showed a moderate growth advantage on avian cultured cells. In 4-week-old chickens inoculated intratracheally with the MZ-delNA virus, viral replication in the lungs, liver, and kidneys was enhanced and interstitial pneumonia lesions were more severe than with the wild-type virus. The MZ-delNA-inoculated chickens showed significantly increased levels of mRNAs encoding interleukin-6 (IL-6), transforming growth factor-?4 (TGF-?4), and CCL5 in the lungs and a higher frequency of apoptotic cells in the liver than did their MZ-inoculated counterparts. Molecular mechanisms possibly underlying the growth advantage of the MZ-delNA virus were explored. The measured enzymatic activities toward a small substrate were similar for the wild-type and deleted NA, but the MZ-delNA virus eluted from chicken erythrocytes at reduced rates. Pseudoviral particles expressing the MZ hemagglutinin in combination with the MZ-NA or MZ-delNA protein were produced from avian cultured cells with similar efficiencies, suggesting that the deletion in the NA stalk does not enhance the release of progeny virions and probably affects an earlier step of the viral cycle. Overall, our data indicate that a shortened NA stalk is a strong determinant of adaptation and virulence of waterfowl influenza viruses in chickens.

Munier, S.; Larcher, T.; Cormier-Aline, F.; Soubieux, D.; Su, B.; Guigand, L.; Labrosse, B.; Cherel, Y.; Quere, P.; Marc, D.; Naffakh, N.

2010-01-01

46

Classical swine fever virus replicon particles lacking the E rns gene: a potential marker vaccine for intradermal application  

Microsoft Academic Search

Classical swine fever virus replicon particles (CSF-VRP) deficient for Erns were eval- uated as a non-transmissible marker vaccine. A cDNA clone of CSFV strain Alfort\\/187 was used to obtain a replication-competent mutant genome (replicon) lacking the sequence encoding the 227 amino acids of the glycoprotein Erns (A187delErns). For packaging of A187delErns into virus parti- cles, porcine kidney cell lines constitutively

Caroline F. Frey; Oliver Bauhofer; Nicolas Ruggli; Artur Summerfield; Martin A. Hofmann; Jon-Duri Tratschin

2006-01-01

47

Future directions: oncolytic viruses.  

PubMed

Oncolytic viruses offer a promising new modality for cancer treatment. The strategy of this therapy is to develop viruses capable of selectively infecting and replicating in malignant tumor cells. Oncolytic viruses can spread and destroy malignant tumors without deleterious effects in normal tissues. These viruses are genetically engineered based on both the biology of replicating viruses and the major genetic defects in human cancer cells, so that they can replicate in cancer cells but not in normal cells. The key to the development of such viruses is the identification of viral genes, the deletion or modification of which enables tumor-specific cell destruction. Several clinical trials have demonstrated the safety of oncolytic viruses as cancer therapy and have also shown some encouraging results. Much evidence suggests that oncolytic viral therapy works in synergy with standard cancer therapies. In this review, we will focus on the oncolytic viruses that may be beneficial to patients with lung cancer in the near future. PMID:14967074

You, Liang; He, Biao; Xu, Zhidong; McCormick, Frank; Jablons, David M

2004-01-01

48

Virus Assembly and Maturation  

NASA Astrophysics Data System (ADS)

We use two techniques to look at three-dimensional virus structure: electron cryomicroscopy (cryoEM) and X-ray crystallography. Figure 1 is a gallery of virus particles whose structures Timothy Baker, one of my former colleagues at Purdue University, used cryoEM to determine. It illustrates the variety of sizes of icosahedral virus particles. The largest virus particle on this slide is the Herpes simplex virus, around 1200Å in diameter; the smallest we examined was around 250Å in diameter. Viruses bear their genomic information either as positive-sense DNA and RNA, double-strand DNA, double-strand RNA, or negative-strand RNA. Viruses utilize the various structure and function "tactics" seen throughout cell biology to replicate at high levels. Many of the biological principles that we consider general were in fact discovered in the context of viruses ...

Johnson, John E.

2004-03-01

49

Live Virus Smallpox Vaccine  

MedlinePLUS

... for Clinicians Brucella Lab Info Surveillance & Investigation Cholera Ebola virus E. coli Food safety threats Glanders Lassa fever Marburg virus Melioidosis Plague Case Definitions and Report Forms Diagnosis & Evaluation Infection Control Lab Testing Surveillance & Investigation Publications & ...

50

Cytotoxicity of Virus.  

National Technical Information Service (NTIS)

Cytotoxic effects through virus capable of propagation such as those of the pox group inactivated by ultraviolet exposure, were produced under high virus-cell ratios in various cell cultures. In the inoculated culture systems, these effects do not propaga...

H. Mahnel

1968-01-01

51

Viruses and Breast Cancer  

PubMed Central

Viruses are the accepted cause of many important cancers including cancers of the cervix and anogenital area, the liver, some lymphomas, head and neck cancers and indirectly human immunodeficiency virus associated cancers. For over 50 years, there have been serious attempts to identify viruses which may have a role in breast cancer. Despite these efforts, the establishment of conclusive evidence for such a role has been elusive. However, the development of extremely sophisticated new experimental techniques has allowed the recent development of evidence that human papilloma virus, Epstein-Barr virus, mouse mammary tumor virus and bovine leukemia virus may each have a role in the causation of human breast cancers. This is potentially good news as effective vaccines are already available to prevent infections from carcinogenic strains of human papilloma virus, which causes cancer of the uterine cervix.

Lawson, James S.; Heng, Benjamin

2010-01-01

52

Viruses and human cancer  

SciTech Connect

This book contains papers on the following topics: Immunology and Epidemiology, Biology and Pathogenesis, Models of Pathogenesis and Treatment, Simian and Bovine Retroviruses, Human Papilloma Viruses, EBV and Herpesvirus, and Hepatitis B Virus.

Gallo, R.C.; Haseltine, W.; Klein, G.; Zur Hausen, H.

1987-01-01

53

[Viruses and mammary carcinogenesis].  

PubMed

Bittner virus has been extensively studied by recent electron microscopy and molecular biology techniques. The structure, the biochemical, physical and antigenic properties of the RNA tumor viruses - i.e. the mouse mammary tumor virus (MMTV) - are well known. Recent observations in human tissues of particles similar to animal viruses that are known to be oncogenic have raised the hypothesis of the role of viruses in human cancer. In mice, breast cancer can be caused by a virus - the Bittner virus or MMTV - that is usually transmitted from mother to offspring in the milk. The discovery of such virus particles in human milks and breast cancer tissues could provide data about a viral aetiology of human breast cancer. PMID:172551

Vokaer, A

1975-01-01

54

Advances in virus research  

SciTech Connect

This book contains eight chapters. Some of the titles are: Initiation of viral DNA replication; Vaccinia: virus, vector, vaccine; The pre-S region of hepadnavirus envelope proteins; and Archaebacterial viruses.

Maramorosch, K. (Rutgers--the State Univ., New Brunswick, NJ (USA)); Murphy, F.A. (Centers for Disease Control, Atlanta, GA (USA)); Shatkin, A.J. (Rutgers-UMDNJ, Piscataway, NJ (US))

1988-01-01

55

Políticas del sitio web  

Cancer.gov

En el sitio web del NCI se proporcionan enlaces a otros sitios web con fines informativos y para conveniencia del público. Si el usuario selecciona un sitio web externo, saldrá del sitio web del NCI y estará sujeto a las políticas de privacidad y seguridad de dicho sitio.

56

[Mumps vaccine virus transmission].  

PubMed

In this work we report the mumps vaccine virus shedding based on the laboratory confirmed cases of the mumps virus (MuV) infection. The likely epidemiological sources of the transmitted mumps virus were children who were recently vaccinated with the mumps vaccine containing Leningrad-Zagreb or Leningrad-3 MuV. The etiology of the described cases of the horizontal transmission of both mumps vaccine viruses was confirmed by PCR with the sequential restriction analysis. PMID:24772647

Otrashevskaia, E V; Kulak, M V; Otrashevskaia, A V; Karpov, I A; Fisenko, E G; Ignat'ev, G M

2013-01-01

57

An Undetectable Computer Virus  

Microsoft Academic Search

One of the few solid theoretical results in the study of computer viruses is Cohen's 1987 demonstration that there is no algorithm that can perfectly detect all possible viruses [1]. This brief paper adds to the bad news, by pointing out that there are computer viruses which no algorithm can detect, even under a somewhat more liberal definition of detection.

David M. Chess; Steve R. White

2000-01-01

58

VIRUSES IN WASTEWATER  

EPA Science Inventory

Viruses of animals, plants, and bacteria abound in sewage and receiving waters. Their ecological impact has, for the most part, gone unheeded except as it relates to viruses from human sources. Viruses present at levels infective to man have been recovered from waters used for re...

59

Constructing Computer Virus Phylogenies  

Microsoft Academic Search

. There has been much recent algorithmic work on the problemof reconstructing the evolutionary history of biological species. Computervirus specialists are interested in finding the evolutionary history of computerviruses --- a virus is often written using code fragments from one ormore other viruses, which are its immediate ancestors. A phylogeny fora collection of computer viruses is a directed acyclic graph

Leslie Ann Goldberg; Paul W. Goldberg; Cynthia A. Phillips; Gregory B. Sorkin

1996-01-01

60

Lipids of Archaeal Viruses  

PubMed Central

Archaeal viruses represent one of the least known territory of the viral universe and even less is known about their lipids. Based on the current knowledge, however, it seems that, as in other viruses, archaeal viral lipids are mostly incorporated into membranes that reside either as outer envelopes or membranes inside an icosahedral capsid. Mechanisms for the membrane acquisition seem to be similar to those of viruses infecting other host organisms. There are indications that also some proteins of archaeal viruses are lipid modified. Further studies on the characterization of lipids in archaeal viruses as well as on their role in virion assembly and infectivity require not only highly purified viral material but also, for example, constant evaluation of the adaptability of emerging technologies for their analysis. Biological membranes contain proteins and membranes of archaeal viruses are not an exception. Archaeal viruses as relatively simple systems can be used as excellent tools for studying the lipid protein interactions in archaeal membranes.

Roine, Elina; Bamford, Dennis H.

2012-01-01

61

Elastic Properties of Viruses  

PubMed Central

Viruses are compact biological nanoparticles whose elastic and dynamical properties are hardly known. Inelastic (Brillouin) light scattering was used to characterize these properties, from microcrystals of the Satellite Tobacco Mosaic Virus, a nearly spherical plant virus of 17-nm diameter. Longitudinal sound velocities in wet and dry Satellite Tobacco Mosaic Virus crystals were determined and compared to that of the well-known protein crystal, lysozyme. Localized vibrational modes of the viral particles (i.e., particle modes) were sought in the relevant frequency ranges, as derived assuming the viruses as full free nanospheres. Despite very favorable conditions, regarding virus concentration and expected low damping in dry microcrystals, no firm evidence of virus particle modes could be detected.

Stephanidis, B.; Adichtchev, S.; Gouet, P.; McPherson, A.; Mermet, A.

2007-01-01

62

Abacá mosaic virus: A distinct strain of Sugarcane mosaic virus  

Microsoft Academic Search

Abacá mosaic virus (AbaMV) is related to members of the sugarcane mosaic virus subgroup of the genus Potyvirus. The ?2 kb 3? terminal region of the viral genome was sequenced and, in all areas analysed, found to be most similar to Sugarcane mosaic virus (SCMV) and distinct from Johnsongrass mosaic virus (JGMV), Maize dwarf mosaic virus (MDMV) and Sorghum mosaic

C. F. Gambley; J. E. Thomas; L. V. Magnaye; L. Herradura

2004-01-01

63

Internet computer virus protection policy  

Microsoft Academic Search

Organizations and individuals today need to have a comprehensive virus protection policy to face the growing threats of Internet computer viruses. The purpose of this paper is to introduce to the reader the threats that Internet computer viruses can cause and provide guidelines on how organizations or individuals can protect themselves against these viruses. Discusses the full set of virus

H. Joseph Wen

1998-01-01

64

Viruses of botrytis.  

PubMed

Botrytis cinerea (gray mold) is one of the most widespread and destructive fungal diseases of horticultural crops. Propagation and dispersal is usually by asexual conidia but the sexual stage (Botryotinia fuckeliana (de Bary) Whetzel) also occurs in nature. DsRNAs, indicative of virus infection, are common in B. cinerea, but only four viruses (Botrytis virus F (BVF), Botrytis virus X (BVX), Botrytis cinerea mitovirus 1 (BcMV1), and Botrytis porri RNA virus) have been sequenced. BVF and BVX are unusual mycoviruses being ssRNA flexous rods and have been designated the type species of the genera Mycoflexivirus and Botrexvirus (family Betaflexivirdae), respectively. The reported effects of viruses on Botrytis range from negligible to severe, with Botrytis cinerea mitovirus 1 causing hypovirulence. Little is currently known about the effects of viruses on Botrytis metabolism but recent complete sequencing of the B. cinerea genome now provides an opportunity to investigate the host-pathogen interactions at the molecular level. There is interest in the possible use of mycoviruses as biological controls for Botrytis because of the common problem of fungicide resistance. Unfortunately, hyphal anastomosis is the only known mechanism of horizontal virus transmission and the large number of vegetative incompatibility groups in Botrytis is a potential constraint on the spread of an introduced virus. Although some Botrytis viruses, such as BVF and BVX, are known to have international distribution, there is a distinct lack of epidemiological data and the means of spread are unknown. PMID:23498909

Pearson, Michael N; Bailey, Andrew M

2013-01-01

65

Instantánea del cáncer colorrectal  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer colorrectal; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

66

The Acute bee paralysis virus–Kashmir bee virus–Israeli acute paralysis virus complex  

Microsoft Academic Search

Acute bee paralysis virus (ABPV), Kashmir bee virus (KBV) and Israeli acute paralysis virus (IAPV) are part of a complex of closely related viruses from the Family Dicistroviridae. These viruses have a widespread prevalence in honey bee (Apis mellifera) colonies and a predominantly sub-clinical etiology that contrasts sharply with the extremely virulent pathology encountered at elevated titres, either artificially induced

Joachim R. de Miranda; Guido Cordoni; Giles Budge

2010-01-01

67

Viruses in Antarctic lakes  

NASA Technical Reports Server (NTRS)

Water samples collected from four perennially ice-covered Antarctic lakes during the austral summer of 1996-1997 contained high densities of extracellular viruses. Many of these viruses were found to be morphologically similar to double-stranded DNA viruses that are known to infect algae and protozoa. These constitute the first observations of viruses in perennially ice-covered polar lakes. The abundance of planktonic viruses and data suggesting substantial production potential (relative to bacteria] secondary and photosynthetic primary production) indicate that viral lysis may be a major factor in the regulation of microbial populations in these extreme environments. Furthermore, we suggest that Antarctic lakes may be a reservoir of previously undescribed viruses that possess novel biological and biochemical characteristics.

Kepner, R. L. Jr; Wharton, R. A. Jr; Suttle, C. A.; Wharton RA, J. r. (Principal Investigator)

1998-01-01

68

Water system virus detection  

NASA Technical Reports Server (NTRS)

The performance of a waste water reclamation system is monitored by introducing a non-pathogenic marker virus, bacteriophage F2, into the waste-water prior to treatment and, thereafter, testing the reclaimed water for the presence of the marker virus. A test sample is first concentrated by absorbing any marker virus onto a cellulose acetate filter in the presence of a trivalent cation at low pH and then flushing the filter with a limited quantity of a glycine buffer solution to desorb any marker virus present on the filter. Photo-optical detection of indirect passive immune agglutination by polystyrene beads indicates the performance of the water reclamation system in removing the marker virus. A closed system provides for concentrating any marker virus, initiating and monitoring the passive immune agglutination reaction, and then flushing the system to prepare for another sample.

Fraser, A. S.; Wells, A. F.; Tenoso, H. J. (inventors)

1978-01-01

69

DNA Virus Replication Compartments  

PubMed Central

Viruses employ a variety of strategies to usurp and control cellular activities through the orchestrated recruitment of macromolecules to specific cytoplasmic or nuclear compartments. Formation of such specialized virus-induced cellular microenvironments, which have been termed viroplasms, virus factories, or virus replication centers, complexes, or compartments, depends on molecular interactions between viral and cellular factors that participate in viral genome expression and replication and are in some cases associated with sites of virion assembly. These virus-induced compartments function not only to recruit and concentrate factors required for essential steps of the viral replication cycle but also to control the cellular mechanisms of antiviral defense. In this review, we summarize characteristic features of viral replication compartments from different virus families and discuss similarities in the viral and cellular activities that are associated with their assembly and the functions they facilitate for viral replication.

Schmid, Melanie; Speiseder, Thomas; Dobner, Thomas

2014-01-01

70

Viruses, masters at downsizing.  

PubMed

Viruses are the smallest fruits on the tree of life. Dwarfed by their bacterial and cellular hosts, viruses and their close relatives have long been considered the smallest microbes. The genome of a virus may contain no more than three thousand nucleotides, compared to the three billion base pairs in human genomes. (Lest we feel superior, though, the genomes of some other organisms are much larger than our own.). PMID:22704616

DiMaio, Daniel

2012-06-14

71

Rabies virus receptors  

Microsoft Academic Search

There is convincing in vitro evidence that the muscular form of the nicotinic acetylcholine receptor (nAChR), the neuronal cell adhesion molecule (NCAM),\\u000a and the p75 neurotrophin receptor (p75NTR) bind rabies virus and\\/or facilitate rabies virus entry into cells. Other components\\u000a of the cell membrane, such as gangliosides, may also participate in the entry of rabies virus. However, little is known

Monique Lafon

2005-01-01

72

Viruses for tumor therapy.  

PubMed

Oncolytic virotherapy exploits live viruses with selective tropism for cancerous cells and tissues to treat cancer. As discussed here, the field has progressed considerably as a result of both the successes and failures of previous and on-going clinical trials for various cancers. These studies indicate that oncolytic viruses are remarkably safe and more efficacious when virus replication stimulates sustained antitumor immune responses. In the future, virotherapy should be combined with immunomodulatory reagents that target immune tolerance to established cancers. PMID:24629333

Bell, John; McFadden, Grant

2014-03-12

73

Avian Influenza A Virus Infections in Humans  

MedlinePLUS

... Google Bookmarks Avian Influenza A Virus Infections in Humans On this Page Avian Influenza A Virus Infections ... A Viruses Avian Influenza A Virus Infections in Humans Although avian influenza A viruses usually do not ...

74

Tracking a Virus  

NSDL National Science Digital Library

Students simulate the spread of a virus such as HIV through a population by "sharing" (but not drinking) the water in a plastic cup with several classmates. Although invisible, the water in a few of the cups has already be tainted with the "virus" (sodium carbonate). After all the students have shared their liquids, the contents of the cups are tested for the virus with phenolphthalein, a chemical that causes a striking color change in the presence of sodium carbonate. Students then set about trying to determine which of their classmates were the ones originally infected with the virus.

Engineering K-Phd Program

75

Water system virus detection  

NASA Technical Reports Server (NTRS)

A monitoring system developed to test the capability of a water recovery system to reject the passage of viruses into the recovered water is described. A nonpathogenic marker virus, bacteriophage F2, is fed into the process stream before the recovery unit and the reclaimed water is assayed for its presence. Detection of the marker virus consists of two major components, concentration and isolation of the marker virus, and detection of the marker virus. The concentration system involves adsorption of virus to cellulose acetate filters in the presence of trivalent cations and low pH with subsequent desorption of the virus using volumes of high pH buffer. The detection of the virus is performed by a passive immune agglutination test utilizing specially prepared polystyrene particles. An engineering preliminary design was performed as a parallel effort to the laboratory development of the marker virus test system. Engineering schematics and drawings of a fully functional laboratory prototype capable of zero-G operation are presented. The instrument consists of reagent pump/metering system, reagent storage containers, a filter concentrator, an incubation/detector system, and an electronic readout and control system.

Fraser, A. S.; Wells, A. F.; Tenoso, H. J.

1975-01-01

76

Viruses in artichoke.  

PubMed

Most of the 25 viruses found in globe artichoke (Cynara scolymus L.) and cardoon (Cynara cardunculus L.) were recorded from Europe and the Mediterranean basin, where they decrease both the productivity and the quality of the crop. Although, sometimes, these viruses are agents of diseases of different severity, most often their infections are symptomless. These conditions have contributed to spread virus-infected material since farmers multiply traditional artichoke types vegetatively with no effective selection of virus-free plants. This review reports the main properties of these viruses and the techniques used for their detection and identification. ELISA kits are commercially available for most of the viruses addressed in this review but have seldom been used for their detection in artichoke. Conversely, nucleic acid-based diagnostic reagents, some of which are commercially available, have successfully been employed to identify some viruses in artichoke sap. Control measures mainly use virus-free stocks for new plantations. A combined procedure of meristem-tip culture and thermotherapy proved useful for producing virus-free regenerants of the reflowering southern Italian cultivar Brindisino, which kept earliness and typical heads shape. PMID:22682171

Gallitelli, Donato; Mascia, Tiziana; Martelli, Giovanni P

2012-01-01

77

Virus separation using membranes.  

PubMed

Industrial manufacturing of cell culture-derived viruses or virus-like particles for gene therapy or vaccine production are complex multistep processes. In addition to the bioreactor, such processes require a multitude of downstream unit operations for product separation, concentration, or purification. Similarly, before a biopharmaceutical product can enter the market, removal or inactivation of potential viral contamination has to be demonstrated. Given the complexity of biological solutions and the high standards on composition and purity of biopharmaceuticals, downstream processing is the bottleneck in many biotechnological production trains. Membrane-based filtration can be an economically attractive and efficient technology for virus separation. Viral clearance, for instance, of up to seven orders of magnitude has been reported for state of the art polymeric membranes under best conditions.This chapter summarizes the fundamentals of virus ultrafiltration, diafiltration, or purification with adsorptive membranes. In lieu of an impractical universally applicable protocol for virus filtration, application of these principles is demonstrated with two examples. The chapter provides detailed methods for production, concentration, purification, and removal of a rod-shaped baculovirus (Autographa californica M nucleopolyhedrovirus, about 40 × 300 nm in size, a potential vector for gene therapy, and an industrially important protein expression system) or a spherical parvovirus (minute virus of mice, 22-26 nm in size, a model virus for virus clearance validation studies). PMID:24297430

Grein, Tanja A; Michalsky, Ronald; Czermak, Peter

2014-01-01

78

Studies on Arbor Viruses.  

National Technical Information Service (NTIS)

Brain antigens from Chikungunya, Semliki, St. Louis, West Nile, and Ntaya viruses as well as antigens from Sindbis virus prepared from the brain tissue of suckling mice and from culture fluid after inoculation of a trypsinized culture of chick embryo fibr...

V. D. Neustroev T. A. Salagova T. A. Rezepova K. S. Kulikov

1968-01-01

79

The hepatitis B virus  

Microsoft Academic Search

DNA recombinant technology has radically changed hepatitis B virus (HBV) virology. The genetic organization, transcription and replication of the virus are basically understood, structures of integrated HBV sequences in hepatocellular carcinoma have been characterized, and new vaccines produced by recombinant DNA technique are being developed.

Pierre Tiollais; Christine Pourcel; Anne Dejean

1985-01-01

80

Recombination in AIDS viruses  

Microsoft Academic Search

Recombination contributes to the generation of genetic diversity in human immunodeficiency viruses (HIV) but can only occur between viruses replicating within the same cell. Since individuals have not been found to be simultaneously coinfected with multiple divergent strains of HIV-1 or HIV-2, recombination events have been thought to be restricted to the rather closely related members of the quasispecies that

David L. Robertson; Beatrice H. Hahn; Paul M. Sharp

1995-01-01

81

Deformed wing virus  

Microsoft Academic Search

Deformed wing virus (DWV; Iflaviridae) is one of many viruses infecting honeybees and one of the most heavily investigated due to its close association with honeybee colony collapse induced by Varroadestructor. In the absence of V.destructor DWV infection does not result in visible symptoms or any apparent negative impact on host fitness. However, for reasons that are still not fully

Joachim R. de Miranda; Elke Genersch

2010-01-01

82

Computer Virus Propagation Models  

Microsoft Academic Search

The availability of reliable models of computer virus propa- gation would prove useful in a number of ways, in order both to predict future threats, and to develop new containment measures. In this pa- per, we review the most popular models of virus propagation, analyzing the underlying assumptions of each of them, their strengths and their weaknesses. We also introduce

Giuseppe Serazzi; Stefano Zanero

2003-01-01

83

Introduction to computer viruses.  

National Technical Information Service (NTIS)

This report on computer viruses is based upon a thesis written for the Master of Science degree in Computer Science from the University of Tennessee in December 1989 by David R. Brown. This thesis is entitled An Analysis of Computer Virus Construction, Pr...

D. R. Brown

1992-01-01

84

Schmallenberg Virus as Possible Ancestor of Shamonda Virus  

PubMed Central

Schmallenberg virus (SBV), an orthobunyavirus of the Simbu serogroup, recently emerged in Europe and has been suggested to be a Shamonda/Sathuperi virus reassortant. Results of full-genome and serologic investigations indicate that SBV belongs to the species Sathuperi virus and is a possible ancestor of the reassortant Shamonda virus.

Goller, Katja V.; Hoper, Dirk; Schirrmeier, Horst; Mettenleiter, Thomas C.

2012-01-01

85

Tobacco Mosaic Virus  

NSDL National Science Digital Library

In this four-part laboratory exercise, learners investigate properties of Tobacco mosaic virus (TMV) including (1) symptoms induced by the virus in susceptible plants at the macroscopic and microscopic levels, (2) its stability at high temperatures, and (3) its small size. Learners first propagate tomato and pinto bean plants, and then inoculate their dried leaves with TMV. Learners observe the TMV-infected leaves as well as use a heat treatment to inactivate the virus. Learners also filter the infected sap with a bacteria-proof filter to investigate size. This lesson guide includes background information, tips for educators, and discussion questions with answers. Adult supervision is recommended. Note: The Tobacco mosaic virus is available from biological suppliers, but approval for shipping of the virus across state lines must be obtained from the USDA prior to shipment.

Ford, Rosemary; Evans, Tom

2011-01-01

86

Hepatitis B Virus Biology  

PubMed Central

Hepadnaviruses (hepatitis B viruses) cause transient and chronic infections of the liver. Transient infections run a course of several months, and chronic infections are often lifelong. Chronic infections can lead to liver failure with cirrhosis and hepatocellular carcinoma. The replication strategy of these viruses has been described in great detail, but virus-host interactions leading to acute and chronic disease are still poorly understood. Studies on how the virus evades the immune response to cause prolonged transient infections with high-titer viremia and lifelong infections with an ongoing inflammation of the liver are still at an early stage, and the role of the virus in liver cancer is still elusive. The state of knowledge in this very active field is therefore reviewed with an emphasis on past accomplishments as well as goals for the future.

Seeger, Christoph; Mason, William S.

2000-01-01

87

Boletín del Instituto Nacional del Cáncer - 16 de enero 2013  

Cancer.gov

El Boletín del Instituto Nacional del Cáncer ha suspendido su publicación a partir del 16 de enero de 2013. El archivo del Boletín, que cuenta con todas las ediciones publicadas desde 2009 a 2013, permanecerá a disposición de los lectores en el sitio web del NCI.

88

Rapid Detection of Enveloped Viruses.  

National Technical Information Service (NTIS)

M-protein of influenza virus is a type-specific antigen and the most invariant protein of the virus. A rapid virus detection system based on M-protein detection would detect all type A influenza viruses and be independent of antigenic shift and drift. To ...

D. J. Bucher

1988-01-01

89

Evolution of avian influenza viruses  

Microsoft Academic Search

Although influenza viruses can infect a wide variety of birds and mammals, the natural host of the virus is wild waterfowl, shorebirds, and gulls. When other species of animals, including chickens, turkeys, swine, horses, and humans, are infected with influenza viruses, they are considered aberrant hosts. The distinction between the normal and aberrant host is important when describing virus evolution

David L. Suarez

2000-01-01

90

Virus-PEDOT Biocomposite Films  

PubMed Central

Virus-poly(3,4-ethylenedioxythiophene) (virus-PEDOT) biocomposite films are prepared by electropolymerizing 3,4-ethylenedioxythiophene (EDOT) in aqueous electrolytes containing 12 mM LiClO4 and the bacteriophage M13. The concentration of virus in these solutions, [virus]soln, is varied from 3 nM to 15 nM. A quartz crystal microbalance is used to directly measure the total mass of the biocomposite film during its electrodeposition. In combination with a measurement of the electrodeposition charge, the mass of the virus incorporated into the film is calculated. These data show that concentration of the M13 within the electropolymerized film, [virus]film, increases linearly with [virus]soln. The incorporation of virus particles into the PEDOT film from solution is efficient, resulting in a concentration ratio: [virus]film:[virus]soln ?450. Virus incorporation into the PEDOT causes roughening of the film topography that is observed using scanning electron microscopy and atomic force microscopy (AFM). The electrical conductivity of the virus-PEDOT film, measured perpendicular to the plane of the film using conductive tip AFM, decreases linearly with virus loading, from 270 ?S/cm for pure PE-DOT films to 50 ?S/cm for films containing 100 ?M virus. The presence on the virus surface of displayed affinity peptides did not significantly influence the efficiency of incorporation into virus-PEDOT biocomposite films.

Donavan, Keith C.; Arter, Jessica A.

2012-01-01

91

A Virus in Turbo Pascal.  

ERIC Educational Resources Information Center

Addresses why the authors feel it is not inappropriate to teach about viruses in the how-to, hands-on fashion. Identifies the special features of Turbo Pascal that have to be used for the creation of an effective virus. Defines virus, derives its structure, and from this structure is derived the implemented virus. (PR)

Teleky, Heidi Ann; And Others

1993-01-01

92

Computer Viruses: Pathology and Detection.  

ERIC Educational Resources Information Center

Explains how computer viruses were originally created, how a computer can become infected by a virus, how viruses operate, symptoms that indicate a computer is infected, how to detect and remove viruses, and how to prevent a reinfection. A sidebar lists eight antivirus resources. (four references) (LRW)

Maxwell, John R.; Lamon, William E.

1992-01-01

93

Ocular Tropism of Respiratory Viruses  

PubMed Central

SUMMARY Respiratory viruses (including adenovirus, influenza virus, respiratory syncytial virus, coronavirus, and rhinovirus) cause a broad spectrum of disease in humans, ranging from mild influenza-like symptoms to acute respiratory failure. While species D adenoviruses and subtype H7 influenza viruses are known to possess an ocular tropism, documented human ocular disease has been reported following infection with all principal respiratory viruses. In this review, we describe the anatomical proximity and cellular receptor distribution between ocular and respiratory tissues. All major respiratory viruses and their association with human ocular disease are discussed. Research utilizing in vitro and in vivo models to study the ability of respiratory viruses to use the eye as a portal of entry as well as a primary site of virus replication is highlighted. Identification of shared receptor-binding preferences, host responses, and laboratory modeling protocols among these viruses provides a needed bridge between clinical and laboratory studies of virus tropism.

Rota, Paul A.; Tumpey, Terrence M.

2013-01-01

94

Enteric hepatitis viruses  

PubMed Central

Hepatitis viruses are infectious agents that can infect liver and cause inflammation. The infection triggers immune response against infected cells that leads to the destruction of hepatic cells. This destruction has two consequences: leaking ALT and AST liver enzymes which increases during the course of disease and accumulation of bilirubin- a red pigmented compound released from dead red cells- which causes the yellow coloration of eyes and skin. These viruses transmit through diverse routes i.e. blood transfusion, sexual contacts and consuming water or food contaminated by feces. Enteric hepatitis viruses use the latter route for transmission; hence their outbreaks are more common in underdeveloped countries. There are currently two distinguished enteric hepatitis viruses, hepatitis A and hepatitis E. These viruses belong to different family of viruses and their epidemiological characteristics are different. These infections can be diagnosed by an ELISA for IgM antibody. A vaccine has been developed in last decade of twentieth century for hepatitis A virus, which is administered mostly in the developed world i.e. U.S and Japan. Treatment for these infections is mostly supportive; however, in the case of fulminant hepatitis the liver transplantation might be necessary.

Tahaei, Seyed Mohammad Ebrahim; Zali, Mohammad Reza

2012-01-01

95

ISOLATION OF Rickettsia bellii FROM Amblyomma ovale AND Amblyomma incisum TICKS FROM SOUTHERN BRAZIL AISLAMIENTO DE Rickettsia bellii A PARTIR DE GARRAPATAS Amblyomma ovale Y Amblyomma incisum PROCEDENTES DEL SUR DE BRASIL  

Microsoft Academic Search

Objective. To isolate and characterize rickettsiae from the ticks Amblyomma ovale and Amblyomma incisum collected in the state of São Paulo. Materials and methods. Adult, free-living A. ovale and A. incisum were collected in an Atlantic rainforest area in the state of São Paulo, Brazil. Each tick was tested using the hemolymph assay; samples from positive ticks were placed in

Richard Pacheco; Simone Rosa; Leonardo Richtzenhain; Matias P. J. Szabó; Marcelo B. Labruna

96

Cucumber mosaic virus.  

PubMed

Cucumber mosaic virus (CMV) is an important virus because of its agricultural impact in the Mediterranean Basin and worldwide, and also as a model for understanding plant-virus interactions. This review focuses on those areas where most progress has been made over the past decade in our understanding of CMV. Clearly, a deep understanding of the role of the recently described CMV 2b gene in suppression of host RNA silencing and viral virulence is the most important discovery. These findings have had an impact well beyond the virus itself, as the 2b gene is an important tool in the studies of eukaryotic gene regulation. Protein 2b was shown to be involved in most of the steps of the virus cycle and to interfere with several basal host defenses. Progress has also been made concerning the mechanisms of virus replication and movement. However, only a few host proteins that interact with viral proteins have been identified, making this an area of research where major efforts are still needed. Another area where major advances have been made is CMV population genetics, where contrasting results were obtained. On the one hand, CMV was shown to be prone to recombination and to show high genetic diversity based on sequence data of different isolates. On the other hand, populations did not exhibit high genetic variability either within plants, or even in a field and the nearby wild plants. The situation was partially clarified with the finding that severe bottlenecks occur during both virus movement within a plant and transmission between plants. Finally, novel studies were undertaken to elucidate mechanisms leading to selection in virus population, according to the host or its environment, opening a new research area in plant-virus coevolution. PMID:22682176

Jacquemond, Mireille

2012-01-01

97

Polyoma BK Virus: An Oncogenic Virus?  

PubMed Central

We report a case of a 65-year-old gentleman with a history of end stage renal disease who underwent a successful cadaveric donor kidney transplant four years ago. He subsequently developed BK virus nephropathy related to chronic immunosuppressant therapy. Three years later, misfortune struck again, and he developed adenocarcinoma of the bladder.

Hassan, Syed; Alirhayim, Zaid; Ahmed, Syed; Amer, Syed

2013-01-01

98

Genome of Horsepox Virus  

PubMed Central

Here we present the genomic sequence of horsepox virus (HSPV) isolate MNR-76, an orthopoxvirus (OPV) isolated in 1976 from diseased Mongolian horses. The 212-kbp genome contained 7.5-kbp inverted terminal repeats and lacked extensive terminal tandem repetition. HSPV contained 236 open reading frames (ORFs) with similarity to those in other OPVs, with those in the central 100-kbp region most conserved relative to other OPVs. Phylogenetic analysis of the conserved region indicated that HSPV is closely related to sequenced isolates of vaccinia virus (VACV) and rabbitpox virus, clearly grouping together these VACV-like viruses. Fifty-four HSPV ORFs likely represented fragments of 25 orthologous OPV genes, including in the central region the only known fragmented form of an OPV ribonucleotide reductase large subunit gene. In terminal genomic regions, HSPV lacked full-length homologues of genes variably fragmented in other VACV-like viruses but was unique in fragmentation of the homologue of VACV strain Copenhagen B6R, a gene intact in other known VACV-like viruses. Notably, HSPV contained in terminal genomic regions 17 kbp of OPV-like sequence absent in known VACV-like viruses, including fragments of genes intact in other OPVs and approximately 1.4 kb of sequence present only in cowpox virus (CPXV). HSPV also contained seven full-length genes fragmented or missing in other VACV-like viruses, including intact homologues of the CPXV strain GRI-90 D2L/I4R CrmB and D13L CD30-like tumor necrosis factor receptors, D3L/I3R and C1L ankyrin repeat proteins, B19R kelch-like protein, D7L BTB/POZ domain protein, and B22R variola virus B22R-like protein. These results indicated that HSPV contains unique genomic features likely contributing to a unique virulence/host range phenotype. They also indicated that while closely related to known VACV-like viruses, HSPV contains additional, potentially ancestral sequences absent in other VACV-like viruses.

Tulman, E. R.; Delhon, G.; Afonso, C. L.; Lu, Z.; Zsak, L.; Sandybaev, N. T.; Kerembekova, U. Z.; Zaitsev, V. L.; Kutish, G. F.; Rock, D. L.

2006-01-01

99

[Enigmatic archaeal viruses].  

PubMed

Viruses infecting microorganisms of the third domain of life, Archaea, are still poorly characterized: to date, only about fifty of these viruses have been isolated. Their hosts are hyperthermophilic, acidothermophilic, and extreme halophilic or methanogenic archaea. Their morphotypes are highly diverse and their gene content is very specific. Some of these viruses have developed extraordinary mechanisms to open the cell wall thanks to the formation of exceptional pyramidal nanostructures. The still limited knowledge about the biology of archaeoviruses should develop rapidly in the coming years. PMID:24330970

Bize, Ariane; Sezonov, Guennadi; Prangishvili, David

2013-01-01

100

Virus templated metallic nanoparticles.  

PubMed

Plant viruses are considered as nanobuilding blocks that can be used as synthons or templates for novel materials. Cowpea mosaic virus (CPMV) particles have been shown to template the fabrication of metallic nanoparticles by an electroless deposition metallization process. Palladium ions were electrostatically bound to the virus capsid and, when reduced, acted as nucleation sites for the subsequent metal deposition from solution. The method, although simple, produced highly monodisperse metallic nanoparticles with a diameter of ca. ?35 nm. CPMV-templated particles were prepared with cobalt, nickel, iron, platinum, cobalt-platinum and nickel-iron. PMID:20877898

Aljabali, Alaa A A; Barclay, J Elaine; Lomonossoff, George P; Evans, David J

2010-12-01

101

Respiratory syncytial virus (RSV)  

MedlinePLUS

... often spreads very rapidly in crowded households and day care centers. The virus can live for a half ... The following increase the risk for RSV: Attending day care Being near tobacco smoke Having school-aged brothers ...

102

Viruses causing gastroenteritis.  

PubMed

Acute gastroenteritis is one of the most common diseases in humans worldwide. Viruses are recognized as important causes of this disease, particularly in children. Since the Norwalk virus was identified as a cause of gastroenteritis, the number of viral agents associated with diarrheal disease in humans has steadily increased. Rotavirus is the most common cause of severe diarrhea in children under 5 years of age. Astrovirus, calicivirus and enteric adenovirus are also important etiologic agents of acute gastroenteritis. Other viruses, such as toroviruses, coronaviruses, picobirnaviruses and pestiviruses, are increasingly being identified as causative agents of diarrhea. In recent years, the availability of diagnostic tests, mainly immunoassays or molecular biology techniques, has increased our understanding of this group of viruses. The future development of a safe and highly effective vaccine against rotavirus could prevent, at least, cases of severe diarrhea and reduce mortality from this disease. PMID:12667234

Wilhelmi, I; Roman, E; Sánchez-Fauquier, A

2003-04-01

103

Hepatitis B virus (image)  

MedlinePLUS

Hepatitis B is also known as serum hepatitis and is spread through blood and sexual contact. It is ... population. This photograph is an electronmicroscopic image of hepatitis B virus particles. (Image courtesy of the Centers for ...

104

Respiratory Syncytial Virus (RSV)  

MedlinePLUS

... and between 12 and 15 months. What is hepatitis B? Hepatitis B is caused by the hepatitis B virus. It can lead to serious liver disease. Signs of hepatitis B infection include belly pain, joint pain, dark urine, ...

105

The influenza viruses  

Microsoft Academic Search

Human epidemic influenza is caused by influenza type A and B viruses, which continually undergo antigenic change in their surface antigens, haemagglutinin (H) and neuraminidase (N). • Influenza epidemics are the consequence of small, ongoing antigenic changes known as \\

Alan W Hampson; John S Mackenzie

2006-01-01

106

Virus Ultra Structure  

NSDL National Science Digital Library

Linda Stannard of the University of Capetown, South Africa, has composed a page which, although it was intended to serve as an introductory manual for students of virology, can be appreciated by a wide audience. A section on the principles of virus architecture uses text and outstanding graphics to provide an introduction to why viruses look the way they do. Other parts of the site emphasize how virus shapes and structures are "seen" and recorded with sections on negative staining and electron microscopy of DNA- and RNA-containing viruses. This site's success relies on the use of well-chosen graphics and the inclusion of interesting factoids such as the following: "The head of a dress-maker's pin can provide seating accommodation for five hundred million rhinoviruses (cause of the common cold)!".

107

Rapid Detection and Quantification of RNA of Ebola and Marburg Viruses, Lassa Virus, Crimean-Congo Hemorrhagic Fever Virus, Rift Valley Fever Virus, Dengue Virus, and Yellow Fever Virus by Real-Time Reverse Transcription-PCR  

Microsoft Academic Search

Viral hemorrhagic fevers (VHFs) are acute infections with high case fatality rates. Important VHF agents are Ebola and Marburg viruses (MBGV\\/EBOV), Lassa virus (LASV), Crimean-Congo hemorrhagic fever virus (CCHFV), Rift Valley fever virus (RVFV), dengue virus (DENV), and yellow fever virus (YFV). VHFs are clinically difficult to diagnose and to distinguish; a rapid and reliable laboratory diagnosis is required in

Christian Drosten; Stephan Göttig; Stefan Schilling; Marcel Asper; Marcus Panning; Herbert Schmitz; Stephan Günther

2002-01-01

108

La teoria del pendolo  

Microsoft Academic Search

Il silenzio era tale che, ascoltando attentamente, si sarebbe potuto udire la voce dell'anima. Era proprio questo il motivo per cui Galileo si alzava ogni mattina di buon ora per dire le sue orazioni innanzi al maestoso altare del duomo. Guardava a lungo le volte intorno a lui cercando con lo sguardo la perfezione del creato e poi, con l'ambiguità

Di Claudio Chillemi

109

Smaller Fleas: Viruses of Microorganisms  

PubMed Central

Life forms can be roughly differentiated into those that are microscopic versus those that are not as well as those that are multicellular and those that, instead, are unicellular. Cellular organisms seem generally able to host viruses, and this propensity carries over to those that are both microscopic and less than truly multicellular. These viruses of microorganisms, or VoMs, in fact exist as the world's most abundant somewhat autonomous genetic entities and include the viruses of domain Bacteria (bacteriophages), the viruses of domain Archaea (archaeal viruses), the viruses of protists, the viruses of microscopic fungi such as yeasts (mycoviruses), and even the viruses of other viruses (satellite viruses). In this paper we provide an introduction to the concept of viruses of microorganisms, a.k.a., viruses of microbes. We provide broad discussion particularly of VoM diversity. VoM diversity currently spans, in total, at least three-dozen virus families. This is roughly ten families per category—bacterial, archaeal, fungal, and protist—with some virus families infecting more than one of these microorganism major taxa. Such estimations, however, will vary with further discovery and taxon assignment and also are dependent upon what forms of life one includes among microorganisms.

Hyman, Paul; Abedon, Stephen T.

2012-01-01

110

Virus templated metallic nanoparticles  

NASA Astrophysics Data System (ADS)

Plant viruses are considered as nanobuilding blocks that can be used as synthons or templates for novel materials. Cowpea mosaic virus (CPMV) particles have been shown to template the fabrication of metallic nanoparticles by an electroless deposition metallization process. Palladium ions were electrostatically bound to the virus capsid and, when reduced, acted as nucleation sites for the subsequent metal deposition from solution. The method, although simple, produced highly monodisperse metallic nanoparticles with a diameter of ca. <=35 nm. CPMV-templated particles were prepared with cobalt, nickel, iron, platinum, cobalt-platinum and nickel-iron.Plant viruses are considered as nanobuilding blocks that can be used as synthons or templates for novel materials. Cowpea mosaic virus (CPMV) particles have been shown to template the fabrication of metallic nanoparticles by an electroless deposition metallization process. Palladium ions were electrostatically bound to the virus capsid and, when reduced, acted as nucleation sites for the subsequent metal deposition from solution. The method, although simple, produced highly monodisperse metallic nanoparticles with a diameter of ca. <=35 nm. CPMV-templated particles were prepared with cobalt, nickel, iron, platinum, cobalt-platinum and nickel-iron. Electronic supplementary information (ESI) available: Additional experimental detail, agarose gel electrophoresis results, energy dispersive X-ray spectra, ?-potential measurements, dynamic light scattering data, nanoparticle tracking analysis and an atomic force microscopy image of Ni-CPMV. See DOI: 10.1039/c0nr00525h

Aljabali, Alaa A. A.; Barclay, J. Elaine; Lomonossoff, George P.; Evans, David J.

2010-12-01

111

Oncogenic Viruses of Nonhuman Primates: A Review.  

National Technical Information Service (NTIS)

Oncogenic viruses of nonhuman primates were reviewed. Viruses of nonhuman primate origin oncogenic in other nonhuman primates includes Herpesvirus saimiri and ateles, simian sarcoma virus, Yaba poxvirus, and oral papilloma virus. SV-40 and simian adenovir...

C. P. Raflo

1975-01-01

112

Evolutionary history of Ebola virus.  

PubMed

SUMMARY Since Ebola virus was discovered in 1970s, the virus has persisted in Africa and sporadic fatal outbreaks in humans and non-human primates have been reported. However, the evolutionary history of Ebola virus remains unclear. In this study, 27 Ebola virus strains with complete glycoprotein genes, including five species (Zaire, Sudan, Reston, Tai Forest, Bundibugyo), were analysed. Here, we propose a hypothesis of the evolutionary history of Ebola virus which will be helpful to investigate the molecular evolution of these viruses. PMID:24040779

Li, Y H; Chen, S P

2014-06-01

113

Evaluación del desempeño integral del sector transporte  

Microsoft Academic Search

Las organizaciones hoy por hoy buscan aplicar un sistema de indicadores que evalúe la gestión y el desempeño del sector transporte en materia económica, social, ambiental e integral, con el fin de garantizar a las partes interesadas una información confiable sobre los resultados de desempeño frente al desarrollo sostenible, que facilite el ingreso a mercados nacionales e internacionales a partir

Clara Inés Pardo Martínez

2007-01-01

114

Recombinant Vaccinia Virus: Immunization against Multiple Pathogens  

NASA Astrophysics Data System (ADS)

The coding sequences for the hepatitis B virus surface antigen, the herpes simplex virus glycoprotein D, and the influenza virus hemagglutinin were inserted into a single vaccinia virus genome. Rabbits inoculated intravenously or intradermally with this polyvalent vaccinia virus recombinant produced antibodies reactive to all three authentic foreign antigens. In addition, the feasibility of multiple rounds of vaccination with recombinant vaccinia virus was demonstrated.

Perkus, Marion E.; Piccini, Antonia; Lipinskas, Bernard R.; Paoletti, Enzo

1985-09-01

115

Multiple virus infections in the honey bee and genome divergence of honey bee viruses  

Microsoft Academic Search

Using uniplex RT-PCR we screened honey bee colonies for the presence of several bee viruses, including black queen cell virus (BQCV), deformed wing virus (DWV), Kashmir bee virus (KBV), and sacbrood virus (SBV), and described the detection of mixed virus infections in bees from these colonies. We report for the first time that individual bees can harbor four viruses simultaneously.

Yanping Chen; Yan Zhao; John Hammond; Hei-ti Hsu; Jay Evans; Mark Feldlaufer

2004-01-01

116

Characterization of K virus and its comparison with polyoma virus.  

PubMed Central

The antigenic relationship between the two murine papovaviruses, K virus and polyoma virus, was examined by serological techniques to determine whether they shared any antigenic components. No cross-reactivity was found associated with the viral (V) antigens by the indirect immunofluorescence, neutralization, or hemagglutination-inhibition tests. The tumor (T) antigens expressed in transformed cells or cells productively infected by either K or polyoma virus did not cross-react by indirect immunofluorescence. An antigenic relationship was detected, however, among the late proteins of K virus, polyoma virus, simian virus 40, and the human papovavirus BKV, when tested with either hyperimmune sera prepared against polyoma virus and simian virus 40 or sera prepared against disrupted virions. The nucleic acids of K and polyoma viruses were compared by agarose gel electrophoresis and restriction endonuclease analysis. No nucleotide sequence homology between the genomes of these two viruses was detectable by DNA-DNA hybridization techniques under stringent conditions. The genome of K virus was found to be slightly smaller than that of polyoma virus, and the cleavage patterns of the viral DNAs with six restriction endonucleases were different. These findings indicate that there is little relationship between these two murine papovaviruses. Images

Bond, S B; Howley, P M; Takemoto, K K

1978-01-01

117

Immunology of hepatitis B virus and hepatitis C virus infection  

Microsoft Academic Search

More than 500 million people worldwide are persistently infected with the hepatitis B virus (HBV) and\\/or hepatitis C virus (HCV) and are at risk of developing chronic liver disease, cirrhosis and hepatocellular carcinoma. Despite many common features in the pathogenesis of HBV- and HCV-related liver disease, these viruses markedly differ in their virological properties and in their immune escape and

Michelina Nascimbeni; Barbara Rehermann

2005-01-01

118

Production of virus resistant plants  

DOEpatents

A method of suppressing virus gene expression in plants using untranslatable plus sense RNA is disclosed. The method is useful for the production of plants that are resistant to virus infection. 9 figs.

Dougherty, W.G.; Lindbo, J.A.

1996-12-10

119

Chlorella viruses isolated in China  

SciTech Connect

Plaque-forming viruses of the unicellular, eukaryotic, exsymbiotic, Chlorella-like green algae strain NC64A, which are common in the United States, were also present in fresh water collected in the People's Republic of China. Seven of the Chinese viruses were examined in detail and compared with the Chlorella viruses previously isolated in the United States. Like the American viruses, the Chinese viruses were large polyhedra and sensitive to chloroform. They contained numerous structural proteins and large double-stranded DNA genomes of at least 300 kilobase pairs. Each of the DNAs from the Chinese viruses contained 5-methyldeoxycytosine, which varied from 12.6 to 46.7% of the deoxycytosine, and N{sup 6}-methyldeoxyadenosine, which varied from 2.2 to 28.3% of the deoxyadenosine. Four of the Chinese virus DNAs hybridized extensively with {sup 32}P-labeled DNA from the American virus PBCV-1, and three hybridized poorly.

Zhang, Y.; Burbank, D.E.; Van Etten, J.L. (Univ. of Nebraska, Lincoln (USA))

1988-09-01

120

Boletín del Instituto Nacional del Cáncer - 07-20-2010  

Cancer.gov

El doctor Harold Varmus, acompañado de su esposa Constance Casey (centro), presta juramento como director del NCI ante la Secretaria del Departamento de Salud y Servicios Humanos, Kathleen Sebelius, el lunes 12 de julio. (Foto cortesía de Chris Smith) El 12 de julio, el doctor Harold Varmus prestó juramento ante la Secretaria del Departamento de Salud y Servicios Humanos de los Estados Unidos, Kathleen Sebelios, como el decimocuarto director del Instituto Nacional del Cáncer.

121

Viruses and Multiple Sclerosis  

PubMed Central

Multiple sclerosis (MS) is a chronic demyelinating disorder of unknown etiology, possibly caused by a virus or virus-triggered immunopathology. The virus might reactivate after years of latency and lyse oligodendrocytes, as in progressive multifocal leukoencephalopathy, or initiate immunopathological demyelination, as in animals infected with Theiler’s murine encephalomyelitis virus or coronaviruses. The argument for a viral cause of MS is supported by epidemiological analyses and studies of MS in identical twins, indicating that disease is acquired. However, the most important evidence is the presence of bands of oligoclonal IgG (OCBs) in MS brain and CSF that persist throughout the lifetime of the patient. OCBs are found almost exclusively in infectious CNS disorders, and antigenic targets of OCBs represent the agent that causes disease. Here, the authors review past attempts to identify an infectious agent in MS brain cells and discuss the promise of using recombinant antibodies generated from clonally expanded plasma cells in brain and CSF to identify disease-relevant antigens. They show how this strategy has been used successfully to analyze antigen specificity in subacute sclerosing panencephalitis, a chronic encephalitis caused by measles virus, and in neuromyelitis optica, a chronic autoimmune demyelinating disease produced by antibodies directed against the aquaporin-4 water channel.

Owens, Gregory P.; Gilden, Don; Burgoon, Mark P.; Yu, Xiaoli; Bennett, Jeffrey L.

2012-01-01

122

Viruses and multiple sclerosis.  

PubMed

Multiple sclerosis (MS) is a chronic demyelinating disorder of unknown etiology, possibly caused by a virus or virus-triggered immunopathology. The virus might reactivate after years of latency and lyse oligodendrocytes, as in progressive multifocal leukoencephalopathy, or initiate immunopathological demyelination, as in animals infected with Theiler's murine encephalomyelitis virus or coronaviruses. The argument for a viral cause of MS is supported by epidemiological analyses and studies of MS in identical twins, indicating that disease is acquired. However, the most important evidence is the presence of bands of oligoclonal IgG (OCBs) in MS brain and CSF that persist throughout the lifetime of the patient. OCBs are found almost exclusively in infectious CNS disorders, and antigenic targets of OCBs represent the agent that causes disease. Here, the authors review past attempts to identify an infectious agent in MS brain cells and discuss the promise of using recombinant antibodies generated from clonally expanded plasma cells in brain and CSF to identify disease-relevant antigens. They show how this strategy has been used successfully to analyze antigen specificity in subacute sclerosing panencephalitis, a chronic encephalitis caused by measles virus, and in neuromyelitis optica, a chronic autoimmune demyelinating disease produced by antibodies directed against the aquaporin-4 water channel. PMID:22130640

Owens, Gregory P; Gilden, Don; Burgoon, Mark P; Yu, Xiaoli; Bennett, Jeffrey L

2011-12-01

123

Nongenital herpes simplex virus.  

PubMed

Nongenital herpes simplex virus type 1 is a common infection usually transmitted during childhood via nonsexual contact. Most of these infections involve the oral mucosa or lips (herpes labialis). The diagnosis of an infection with herpes simplex virus type 1 is usually made by the appearance of the lesions (grouped vesicles or ulcers on an erythematous base) and patient history. However, if uncertain, the diagnosis of herpes labialis can be made by viral culture, polymerase chain reaction, serology, direct fluorescent antibody testing, or Tzanck test. Other nonoral herpes simplex virus type 1 infections include herpetic keratitis, herpetic whitlow, herpes gladiatorum, and herpetic sycosis of the beard area. The differential diagnosis of nongenital herpes simplex virus infection includes aphthous ulcers, acute paronychia, varicella-zoster virus infection, herpangina, herpes gestationis (pemphigoid gestationis), pemphigus vulgaris, and Behçet syndrome. Oral acyclovir suspension is an effective treatment for children with primary herpetic gingivostomatitis. Oral acyclovir, valacyclovir, and famciclovir are effective in treating acute recurrence of herpes labialis (cold sores). Recurrences of herpes labialis may be diminished with daily oral acyclovir or valacyclovir. Topical acyclovir, penciclovir, and docosanol are optional treatments for recurrent herpes labialis, but they are less effective than oral treatment. PMID:21121552

Usatine, Richard P; Tinitigan, Rochelle

2010-11-01

124

Hojas informativas del NCI  

Cancer.gov

La colección de hojas informativas del NCI trata de una variedad de temas relacionados con el cáncer. Las hojas informativas se revisan y ponen al día de acuerdo a las investigaciones más recientes sobre el cáncer.

125

Virus Evolution and Population Dynamics  

Microsoft Academic Search

It is intuitive that the field of virology is a discipline integral to the medical sciences. The affiliation of virology with population and conservation biology may not be as apparent. However, viruses, and in particular, virus evolution, may both contribute to and be a significant tool to understand changes in host population structure. The impact of viruses is most notable

Mary Poss; Roman Biek; Allen Rodrigo

126

Rhabdomyolysis Associated with Parainfluenza Virus  

PubMed Central

Influenza virus is the most frequently reported viral cause of rhabdomyolysis. A 7-year-old child is presented with rhabdomyolysis associated with parainfluenza type 2 virus. Nine cases of rhabdomyolysis associated with parainfluenza virus have been reported. Complications may include electrolyte disturbances, acute renal failure, and compartment syndrome.

Kielbasa, Johanna M.; Chandrasekharan, Gopal M.; Holmes, Cynthia L.; Gomez, Michael R.

2013-01-01

127

Novel avian influenza virus vaccines  

Microsoft Academic Search

Summary Current vaccines against avian influenza (AI) virus infections are primarily based on classical inactivated whole-virus preparations. Although administration of these vaccines can protect poultry from clinical disease, sterile immunity is not achieved under field conditions, allowing for undetected virus spread and evolution under immune cover. Therefore, there is an urgent need for a robust and reliable system of differentiation

W. Fuchs; A. Römer-Oberdörfer; J. Veits; T. C. Mettenleiter

2009-01-01

128

Virus Necrosis of Tobacco Veins.  

National Technical Information Service (NTIS)

Virus necrosis of tobacco veins (browning of tobacco veins) occurs all over Poland and causes major economic losses. Studies of a number of orders show that the necrosis of tobacco veins is caused by a virus, which belongs to the group of potato virus Y (...

J. Berbec

1964-01-01

129

An introduction to computer viruses  

SciTech Connect

This report on computer viruses is based upon a thesis written for the Master of Science degree in Computer Science from the University of Tennessee in December 1989 by David R. Brown. This thesis is entitled An Analysis of Computer Virus Construction, Proliferation, and Control and is available through the University of Tennessee Library. This paper contains an overview of the computer virus arena that can help the reader to evaluate the threat that computer viruses pose. The extent of this threat can only be determined by evaluating many different factors. These factors include the relative ease with which a computer virus can be written, the motivation involved in writing a computer virus, the damage and overhead incurred by infected systems, and the legal implications of computer viruses, among others. Based upon the research, the development of a computer virus seems to require more persistence than technical expertise. This is a frightening proclamation to the computing community. The education of computer professionals to the dangers that viruses pose to the welfare of the computing industry as a whole is stressed as a means of inhibiting the current proliferation of computer virus programs. Recommendations are made to assist computer users in preventing infection by computer viruses. These recommendations support solid general computer security practices as a means of combating computer viruses.

Brown, D.R.

1992-03-01

130

Il problema del litio.  

NASA Astrophysics Data System (ADS)

Contents: 1. Introduzione. 2. La nucleosintesi del Big Bang. 3. Il litio nelle stelle di popolazione II. 4. I modelli stellari standard. 5. Il litio negli ammassi aperti. 6. Meccanismi di distruzione "non standard". 7. I modelli non-standard applicati alla popolazione II. 8. L'evoluzione Galattica del litio. 9. Quali stelle producono litio? 10. Il litio come elemento chiave per dare un nome agli oggetti stellari più minuscoli. 11. Conclusioni.

D'Antona, F.

1995-03-01

131

Deformed wing virus.  

PubMed

Deformed wing virus (DWV; Iflaviridae) is one of many viruses infecting honeybees and one of the most heavily investigated due to its close association with honeybee colony collapse induced by Varroadestructor. In the absence of V.destructor DWV infection does not result in visible symptoms or any apparent negative impact on host fitness. However, for reasons that are still not fully understood, the transmission of DWV by V.destructor to the developing pupae causes clinical symptoms, including pupal death and adult bees emerging with deformed wings, a bloated, shortened abdomen and discolouration. These bees are not viable and die soon after emergence. In this review we will summarize the historical and recent data on DWV and its relatives, covering the genetics, pathobiology, and transmission of this important viral honeybee pathogen, and discuss these within the wider theoretical concepts relating to the genetic variability and population structure of RNA viruses, the evolution of virulence and the development of disease symptoms. PMID:19909976

de Miranda, Joachim R; Genersch, Elke

2010-01-01

132

Neuroinvasion by Chandipura virus.  

PubMed

Chandipura virus (CHPV) is an arthropod borne rhabdovirus associated with acute encephalitis in children below the age of 15 years in the tropical states of India. Although the entry of the virus into the nervous system is among the crucial events in the pathogenesis of CHPV, the exact mechanism allowing CHPV to invade the central nervous system (CNS) is currently poorly understood. In the present review, based on the knowledge of host interactors previously predicted for CHPV, along with the support from experimental data available for other encephalitic viruses, the authors have speculated the various plausible modes by which CHPV could surpass the blood-brain barrier and invade the CNS to cause encephalitis whilst evading the host immune surveillance. Collectively, this review provides a conservative set of potential interactions that can be employed for future experimental validation with a view to better understand the neuropathogenesis of CHPV. PMID:24713200

Rajasekharan, Sreejith; Rana, Jyoti; Gulati, Sahil; Gupta, Vandana; Gupta, Sanjay

2014-07-01

133

Viruses in water  

PubMed Central

Attention is drawn in this paper to the increasing problem of viral contamination of water and shellfish, particularly since growing demands for available water resources by a rising world population and expanding industry will make the recycling of wastewater almost inevitable in the future. The problem of eliminating viruses pathogenic for man from water is considered in the light of present water treatment procedures, which are often inadequate for that purpose. Man may be exposed to waterborne viruses through the consumption of contaminated water, shellfish, or crops, as a result of recreational activities involving water, or from aerosols following the spraying of crops with liquid wastes. Physical and chemical methods of eliminating viruses from water are discussed.

Melnick, Joseph L.; Gerba, Charles P.; Wallis, Craig

1978-01-01

134

Bagaza virus and Israel turkey meningoencephalomyelitis virus are a single virus species.  

PubMed

Bagaza virus (BAGV) and Israel turkey meningoencephalomyelitis virus (ITV) are classified in the genus Flavivirus of the family Flaviviridae. Serologically, they are closely related, belonging to the Ntaya serocomplex. Nucleotide sequences available to date consist of several complete sequences of BAGV isolates, but only partial sequences of ITV isolates. Sequence comparisons of partial envelope (E) and NS5 regions reveal a close genetic relationship between these viruses. Despite this, BAGV and ITV are considered as separate virus species in the database of the International Committee on Taxonomy of Viruses. In this work, complete nucleotide sequences for five ITV isolates are provided, thereby permitting a phylogenetic comparison with other complete sequences of flaviviruses in the Ntaya serogroup. We conclude that BAGV and ITV are the same virus species and propose that both viruses be designated by a new unified name: Avian meningoencephalomyelitis virus. PMID:24457974

Fernández-Pinero, Jovita; Davidson, Irit; Elizalde, Maia; Perk, Shimon; Khinich, Yevgeny; Jiménez-Clavero, Miguel Angel

2014-04-01

135

Amenazas comerciales del Acuerdo Can-Mercosur para los sectores productivos del Valle del Cauca  

Microsoft Academic Search

El Acuerdo de Complementación Económica, suscrito entre la Comunidad Andina (CAN) y el Mercado Común del Sur (MERCOSUR), marca un avance hacia una integración económica y política más profunda en América Latina. Por tal razón, el objetivo del presente artículo es identificar los sectores del Valle del Cauca que revelan desventajas competitivas relativas, por lo que se pueden ver potencialmente

Lya Paola Sierra Suárez; José Tomás Peláez Soto

2008-01-01

136

EL DESARROLLO DEL PENSAMIENTO CRÍTICO DEL ESTUDIANTE. UNA FINALIDAD EDUCATIVA PENDIENTE DEL ÁREA CURRICULAR ESTUDIOS SOCIALES  

Microsoft Academic Search

Esta investigación tuvo como objetivo determinar las características del proceso instruccional en la tercera etapa del nivel de Educación Básica que contribuyen al desarrollo del pensamiento crítico del estudiante para satisfacer el imperativo legal vigente desde julio de 1980, particularmente para el área curricular Estudios Sociales. Durante cuatro años escolares en dos instituciones educativas que ofrecen el precitado nivel se

Haydée Páez

137

Espectroscopia del Cometa Halley  

NASA Astrophysics Data System (ADS)

Se reportan observaciones espectroscópicas del cometa Halley. Los espectros fueron tomados usando el espectrógrafo del telescopio reflector de 1 metro del Observatorio Nacional de Venezuela. Se utilizó óptica azul, con una red de difracción de 600 lineas/min, obteniéndose una dispersión de 74.2 A/mm y una resolución de 2.5 A, en el rango espectral de 3500 a 6500 A. Seis placas fueron tomadas con emulsión IIa-O y dos con IIa-D. Los tiempos de exposición fueron entre 10 y 150 minutos. El cometa se encontraba entre 0.70 y 1.04 UA del Sol, y entre 1.28 y 0.73 UA de la Tierra. Las emisiones más prominentes en el espectro, son las del CN, C2, y C3. Otras emisiones detectadas corresponden a CH, NH2 y Na. Los espectros muestran un fuerte continuo, indicando un contenido significativo de polvo. Se detectó mayor intensidad del contínuo, en la dirección anti solar, lo cual es evidencia de la cola de polvo.

Naranjo, O.; Fuenmayor, F.; Ferrin, L.; Bulka, P.; Mendoza, C.

1987-05-01

138

West Nile virus.  

PubMed

West Nile virus infection has quickly become a feared cause of neurologic disability and death, particularly when it presents with encephalitis. Recent epidemics in endemic regions of Eurasia and Africa, as well as its recent spread to North America, have highlighted the need for all physicians to be aware of its clinical presentation and course. In particular, because of the increased susceptibility of West Nile virus infection during outdoor activities, as well as during travel to the Middle East and Southeastern Europe, military physicians should be informed about case recognition, management, and prevention to maintain the health of soldiers and their families. PMID:15132225

Brandt, Antonio L; Martyak, Nicholas; Westhoff, John; Kang, Christopher

2004-04-01

139

Autophagy by hepatitis B virus and for hepatitis B virus.  

PubMed

Autophagy is a catabolic process by which cells remove unwanted proteins and damaged organelles. It is important for maintaining cellular homeostasis and can also be used by cells to remove intracellular microbial pathogens. As such, some viruses such as herpes simplex virus-1 (HSV-1) have evolved mechanisms to suppress autophagy for their survival. In contrast, other viruses such as poliovirus, hepatitis C virus (HCV) and dengue viruses have instead evolved mechanisms to use this pathway to enhance their replication. Recently, we demonstrated that hepatitis B virus (HBV), a DNA virus that infects hepatocytes, could enhance and use autophagy for its DNA replication. This enhancement of autophagy is mediated by its X protein, which binds to and activates phosphatidylinositol-3-kinase class 3 (PI3KC3), an enzyme important for the initiation of autophagy. The persistent activation of autophagy in hepatocytes by HBV during chronic infection may play an important role in HBV pathogenesis. PMID:20305390

Sir, Donna; Ann, David K; Ou, Jing-Hsiung James

2010-05-01

140

Bat Flight and Zoonotic Viruses  

PubMed Central

Bats are sources of high viral diversity and high-profile zoonotic viruses worldwide. Although apparently not pathogenic in their reservoir hosts, some viruses from bats severely affect other mammals, including humans. Examples include severe acute respiratory syndrome coronaviruses, Ebola and Marburg viruses, and Nipah and Hendra viruses. Factors underlying high viral diversity in bats are the subject of speculation. We hypothesize that flight, a factor common to all bats but to no other mammals, provides an intensive selective force for coexistence with viral parasites through a daily cycle that elevates metabolism and body temperature analogous to the febrile response in other mammals. On an evolutionary scale, this host–virus interaction might have resulted in the large diversity of zoonotic viruses in bats, possibly through bat viruses adapting to be more tolerant of the fever response and less virulent to their natural hosts.

Cryan, Paul M.; Cunningham, Andrew A.; Fooks, Anthony R.; Hayman, David T.S.; Luis, Angela D.; Peel, Alison J.; Plowright, Raina K.; Wood, James L.N.

2014-01-01

141

Bat flight and zoonotic viruses.  

PubMed

Bats are sources of high viral diversity and high-profile zoonotic viruses worldwide. Although apparently not pathogenic in their reservoir hosts, some viruses from bats severely affect other mammals, including humans. Examples include severe acute respiratory syndrome coronaviruses, Ebola and Marburg viruses, and Nipah and Hendra viruses. Factors underlying high viral diversity in bats are the subject of speculation. We hypothesize that flight, a factor common to all bats but to no other mammals, provides an intensive selective force for coexistence with viral parasites through a daily cycle that elevates metabolism and body temperature analogous to the febrile response in other mammals. On an evolutionary scale, this host-virus interaction might have resulted in the large diversity of zoonotic viruses in bats, possibly through bat viruses adapting to be more tolerant of the fever response and less virulent to their natural hosts. PMID:24750692

O'Shea, Thomas J; Cryan, Paul M; Cunningham, Andrew A; Fooks, Anthony R; Hayman, David T S; Luis, Angela D; Peel, Alison J; Plowright, Raina K; Wood, James L N

2014-05-01

142

Interaction of Venezuelan Equine Encephalomyelitis Virus with Neutralizing Antibody: II. The Persistent Virus Fraction.  

National Technical Information Service (NTIS)

The persistent virus fraction that results from the interaction of Venezuelan equine encephalomyelitis (VEE) virus with antiviral serum is an infectious virus-antibody complex (sensitized virus) that can be neutralized by anti-IgG serum. The quantities of...

N. Hahon

1969-01-01

143

Biology of parainfluenza viruses.  

PubMed Central

Parainfluenza virus types 1 to 4 (PIV1 to PIV4) are important human pathogens that cause upper and lower respiratory tract infections, especially in infants and children. PIV1, PIV2, and PIV3 are second only to respiratory syncytial virus as a cause of croup in young children. Although some clinical symptoms are typical of PIVs, etiologic diagnosis always requires detection of infectious virus, viral components, or an antibody response. PIVs are typical paramyxoviruses, causing a syncytial cytopathic effect in cell cultures; virus growth can be confirmed either by hemadsorption or by using immunological reagents. Currently, PIV is most often diagnosed by demonstrating viral antigens in clinical specimens by rapid and highly sensitive immunoassays. More recently, PCR has been used for the detection of PIVs. Serological diagnosis is made by detecting a rising titer of immunoglobulin G or by demonstrating immunoglobulin M antibodies. PIVs infect species other than humans, and animal models are used to study the pathogenesis of PIV infections and to test candidate vaccines. Accumulating knowledge on the molecular structure and mechanisms of replication of PIVs has accelerated research on prevention and treatment. Several strategies for vaccine development, such as the use of live attenuated, inactivated, recombinant, and subunit vaccines, have been investigated, and it may become possible to prevent PIV infections in the near future.

Vainionpaa, R; Hyypia, T

1994-01-01

144

From Shakespeare to Viruses  

SciTech Connect

Berkeley Lab scientists have created a unique new tool for analyzing and comparing long sets of data, be it the genomes of mammals or viruses, or the works of Shakespeare. The results of the Shakespeare analysis surprised scholars with their accuracy

Sung-Hou Kim

2009-02-09

145

Yellow Fever Virus Infection  

PubMed Central

A sequential and quantitative survey of brain and liver of suckling mice for infective virus and complement-fixing antigen, after infection with yellow fever virus, showed that while there was progressive increase of infective virus content in both organs, only the brain showed a corresponding rise in CF antigen. Histopathological examination revealed that the liver was not significantly involved. The target organ was the brain, where the progressive pathological changes culminated in an acute encephalitis by the 3rd day of experiment. Organ destruction began with the molecular layer of the grey matter. But by the 4th day after infection the entire cerebral cortex was involved. At the initial stages the hippocampus was particularly affected. Tissue damage did not appear to be entirely due to the differential quantitative localization of infective virus. It was hypothesized that the CF antigen acting singly or in conjunction with some hypothetical proteins may be principally involved in the pathological outcome of the disease. ImagesFigs. 7-9Figs. 3-6

David-West, Tam. S.; Smith, J. A.

1971-01-01

146

Virus Inactivation Kinetics  

Microsoft Academic Search

At the session of the Research Group of the Standing Technical Committee of the European Commission for the Control of Foot-and-Mouth Disease in Gerzensee, Berne, Switzerland in September 2003 a review of methods for describing the effect of temperature and time upon virus survival in products was presented (Have, 2003). The Research Group recommended that \\

Soren Alexandersen

147

Cold Facts about Viruses.  

ERIC Educational Resources Information Center

Provides ways for students to demonstrate their understanding of scientific concepts and skills. Describes a mini-unit around the cold in which students can relate humans to viruses. Includes activities and a modified simulation that provides questions to guide students. Discusses ways that allows students to apply prior knowledge, take ownership…

Pea, Celeste; Sterling, Donna R.

2002-01-01

148

Turnip Yellow Mosaic Virus  

NASA Technical Reports Server (NTRS)

The bumpy exterior of the turnip yellow mosaic virus (TYMV) protein coat, or capsid, was defined in detail by Dr. Alexander McPherson of the University of California, Irvin using proteins crystallized in space for analysis on Earth. TYMV is an icosahedral virus constructed from 180 copies of the same protein arranged into 12 clusters of five proteins (pentamers), and 20 clusters of six proteins (hexamers). The final TYMV structure led to the unexpected hypothesis that the virus releases its RNA by essentially chemical-mechanical means. Most viruses have fairly flat coats, but in TYNV, the fold in each protein, called the jellyroll, is clustered at the points where the protein pentamers and hexamers join. The jellyrolls are almost standing on end, producing a bumpy surface with knobs at all of the pentamers and hexamers. At the inside surface of the pentamers is a void that is not present at the hexamers. The coating had been seen in early stuties of TYMV, but McPherson's atomic structure shows much more detail. The inside surface is strikingly, and unexpectedly, different than the outside. While the pentamers contain a central void on the inside, the hexameric units contain peptides linked to each other, forming a ring or, more accurately, rings to fill the void. Credit: Dr. Alexander McPherson, University of California, Irvine

2000-01-01

149

West Nile Virus, Guadeloupe  

PubMed Central

To determine whether West Nile virus (WNV) had reached the archipelago of Guadeloupe, a serologic study in horses and birds was conducted in 2002. Immunoglobulin (Ig) G, IgM, enzyme-linked immunosorbent assay, and seroneutralization tests identified WNV infection in horses and chickens. Six months later, a high rate of seroconversion was observed in horses.

Quirin, Rene; Salas, Michel; Zientara, Stephan; Zeller, Herve; Labie, Jacques; Murri, Severine; Lefrancois, Thierry; Petitclerc, Martial

2004-01-01

150

Viruses and autophagy  

PubMed Central

SUMMARY Autophagy is an evolutionarily conserved intracellular process by which bulk cytoplasm is enveloped inside a double-membraned vesicle and shuttled to lysosomes for degradation. Within the last 15 years, the genes necessary for the execution of autophagy have been identified and the number of tools for studying this process has grown. Autophagy is essential for tissue homeostasis and development and defective autophagy is associated with a number of diseases. As intracellular parasites, during the course of an infection, viruses encounter autophagy and interact with the proteins that execute this process. Autophagy and/or autophagy genes likely play both anti-viral and proviral roles in the life cycles and pathogenesis of many different virus families. With respect to anti-viral roles, the autophagy proteins function in targeting viral components or virions for lysosomal degradation in a process termed xenophagy, and they also play a role in the initiation of innate and adaptive immune system responses to viral infections. Consistent with this anti-viral role of host autophagy, some viruses encode virulence factors that interact with the host autophagy machinery and block the execution of autophagy. In contrast, other viruses appear to utilise components of the autophagic machinery to foster their own intracellular growth or non-lytic cellular egress. As the details of the role(s) of autophagy in viral pathogenesis become clearer, new anti-viral therapies could be developed to inhibit the beneficial and enhance the destructive aspects of autophagy on the viral life cycle.

Kudchodkar, Sagar B.; Levine, Beth

2010-01-01

151

Transmisión vertical del VIH  

Microsoft Academic Search

SUMMARY Prevention of perinatal transmission of the human immunodeficency virus is a major goal in the manage- ment of pregnant women infected with HIV. Effectiveness of zidovudine as a preventive agent has been pro- bably one of the most important advances in this regard. Later evidence has shown the benefit of employing combination antiretroviral therapy in reducing the transmission as

C. Martí; A. Guntiñas; C. Sanz; G. Vegas; I. Bates; J. M. Peña; R. Usandizaga

2002-01-01

152

Viruses and bacteriophages.  

PubMed

Many of the enteric viruses which are transmitted from person to person by the fecal-oral route are found in raw and treated wastewater, and because of their persistence under adverse conditions may also be found in slightly polluted waters. There is no routine examination procedure of water and wastewater for enteroviruses, mainly because of the cumbersome isolation techniques, high cost and the need for highly skilled laboratory personnel. Phages are specific to single species of bacteria, are known for many enteric bacteria, and are very often used for final identification of enteric pathogenic bacteria. Coliphages are prevalent in raw and treated sewage as well as in polluted water, where enteric viruses may also be found. Coliphages were often mentioned as possible viral indicators in polluted water. To be a perfect indicator, they should comply with minimum criteria as follows: (a) they should be present wherever human enteric viruses are present; (b) the coliphage numbers recovered should be equal to or larger than those of enteric viruses recovered; (c) the coliphages should be at least as resistant as enteric viruses to adverse environmental conditions; (d) isolation and quantification of the coliphage should be faster and less expensive than isolation of the enteroviruses. Comparative studies show that the coliphage to enterovirus ratio in wastewater is about 10(3):1. Levels of poliovirus 1 (attenuated) to coliphage f2 remained stable for a few months in oxidation pond effluents. f2 coliphage exhibited higher resistance to chlorination than poliovirus 1 (attenuated). When the two strains were kept in water of different quality, f2 survived longer. In addition, all coliphage counts were completed within 24 h. while those of enteroviruses required about a week. Results indicate very strongly that coliphages can be used as viral indicators and this is already the practice in a few European and other countries. PMID:6262909

Kott, Y

1981-04-01

153

Recombinant Vaccinia Virus: Immunization against Multiple Pathogens  

Microsoft Academic Search

The coding sequences for the hepatitis B virus surface antigen, the herpes simplex virus glycoprotein D, and the influenza virus hemagglutinin were inserted into a single vaccinia virus genome. Rabbits inoculated intravenously or intradermally with this polyvalent vaccinia virus recombinant produced antibodies reactive to all three authentic foreign antigens. In addition, the feasibility of multiple rounds of vaccination with recombinant

Marion E. Perkus; Antonia Piccini; Bernard R. Lipinskas; Enzo Paoletti

1985-01-01

154

Neural networks for computer virus recognition  

Microsoft Academic Search

We have developed a neural network for generic detection of a particular class of computer viruses-the so called boot sector viruses that infect the boot sector of a floppy disk or a hard drive. This is an important and relatively tractable subproblem of generic virus detection. Only about 5% of all known viruses are boot sector viruses, yet they account

G. J. Tesauro; J. O. Kephart; G. B. Sorkin

1996-01-01

155

Measuring and modeling computer virus prevalence  

Microsoft Academic Search

To understand the current extent of the computer virus problem and predict its future course, the authors have conducted a statistical analysis of computer virus incidents in a large, stable sample population of PCs and developed new epidemiological models of computer virus spread. Only a small fraction of all known viruses have appeared in real incidents, partly because many viruses

Jeffrey O. Kephart; Steve R. White

1993-01-01

156

Virus entry mediated by hepatitis B virus envelope proteins  

PubMed Central

Hepatitis B virus (HBV), a major cause of human liver disease worldwide, encodes three envelope proteins needed for the attachment and entry of the virus into susceptible host cells. A second virus, hepatitis delta virus, which is known to enhance liver disease in HBV infected patients, diverts the same HBV envelope proteins to achieve its own assembly and infection. In the lab, lentiviral vectors based on human immunodeficiency virus type 1 can be assembled using the HBV envelope proteins, and will similarly infect susceptible cells. This article provides a partial review and some personal reflections of how these three viruses infect and of how recipient cells become susceptible, along with some consideration of questions that remain to be answered.

Taylor, John M

2013-01-01

157

Active virus filter for enrichment and manipulation of virus  

Microsoft Academic Search

We developed an active virus filter (AVF) that was able to virus enrichment and distribution for single virus manipulation by using the insulator based dielectrophoresis (iDEP). The design of constricted flow channel enabled the microfluidic chip to produce iDEP force. We utilized maskless photolithography to achieve the precise 3D gray-scale exposure for constricted flow channel. When we applied sinusoidal wave

T. Masuda; H. Maruyama; A. Honda; F. Arai

2011-01-01

158

Human herpes virus 8: a new virus discloses its face  

Microsoft Academic Search

The human herpes virus 8 (HHV8) or Kaposi’s sarcoma-associated herpes virus (KSHV) is present in all Kaposi’s sarcoma, and\\u000a the detection of the virus using polymerase chain reaction or in situ hybridization is a highly sensitive and specific diagnostic\\u000a test for the diagnosis of this neoplasm. HHV8 is furthermore invariably present in primary effusion lymphoma (PEL) and has\\u000a also been

Gieri Cathomas

2000-01-01

159

Instantánea del cáncer de esófago  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de esófago; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

160

Instantánea del cáncer de próstata  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de próstata; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

161

Instantánea del cáncer de estómago  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de estómago; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

162

Instantánea del sarcoma de Kaposi  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el sarcoma de Kaposi; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

163

Instantánea del cáncer de tiroides  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de tiroides; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

164

Instantánea del cáncer de ovario  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de ovario; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

165

Instantánea del cáncer de endometrio  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de endometrio; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

166

Instantánea del cáncer de vejiga  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de vejiga; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

167

Instantánea del cáncer de riñón  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de riñón; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

168

Instantánea del cáncer de páncreas  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de páncreas; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

169

Instantánea del cáncer de pulmón  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de pulmón; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

170

Molecular characterization and experimental host range of an isolate of Wissadula golden mosaic St. Thomas virus.  

PubMed

Partial genome segments of a begomovirus were previously amplified from Wissadula amplissima exhibiting yellow-mosaic and leaf-curl symptoms in the parish of St. Thomas, Jamaica and this isolate assigned to a tentative begomovirus species, Wissadula golden mosaic St. Thomas virus. To clone the complete genome of this isolate of Wissadula golden mosaic St. Thomas virus, abutting primers were designed to PCR amplify its full-length DNA-A and DNA-B components. Sequence analysis of the complete begomovirus genome obtained, confirmed that it belongs to a distinct begomovirus species and this isolate was named Wissadula golden mosaic St. Thomas virus-[Jamaica:Albion:2005] (WGMSTV-[JM:Alb:05]). The genome of WGMSTV-[JM:Alb:05] is organized similar to that of other bipartite Western Hemisphere begomoviruses. Phylogenetic analyses placed the genome components of WGMSTV-[JM:Alb:05] in the Abutilon mosaic virus clade and showed that the DNA-A component is most closely related to four begomovirus species from Cuba, Tobacco leaf curl Cuba virus, Tobacco leaf rugose virus, Tobacco mottle leaf curl virus, and Tomato yellow distortion leaf virus. The putative Rep-binding-site motif in the common region of WGMSTV-[JM:Alb:05] was observed to be identical to that of Chino del tomate virus-Tomato [Mexico:Sinaloa:1983], Sida yellow mosaic Yucatan virus-[Mexico:Yucatan:2005], and Tomato leaf curl Sinaloa virus-[Nicaragua:Santa Lucia], suggesting that WGMSTV-[JM:Alb:05] is capable of forming viable pseudo-recombinants with these begomoviruses, but not with other members of the Abutilon mosaic virus clade. Biolistic inoculation of test plant species with partial dimers of the WGMSTV-[JM:Alb:05] DNA-A and DNA-B components showed that the virus was infectious to Nicotiana benthamiana and W. amplissima and the cultivated species Phaseolus vulgaris (kidney bean) and Lycopersicon esculentum (tomato). Infected W. amplissima plants developed symptoms similar to symptoms observed under field conditions, confirming that this virus is a causal agent of Wissadula yellow mosaic disease in W. amplissima. PMID:19768650

Collins, A M; Mujaddad-ur-Rehman, Malik; Brown, J K; Reddy, C; Wang, A; Fondong, V; Roye, M E

2009-12-01

171

Viruses from extreme thermal environments  

PubMed Central

Viruses of extreme thermophiles are of great interest because they serve as model systems for understanding the biochemistry and molecular biology required for life at high temperatures. In this work, we report the discovery, isolation, and preliminary characterization of viruses and virus-like particles from extreme thermal acidic environments (70–92°C, pH 1.0–4.5) found in Yellowstone National Park. Six unique particle morphologies were found in Sulfolobus enrichment cultures. Three of the particle morphologies are similar to viruses previously isolated from Sulfolobus species from Iceland and/or Japan. Sequence analysis of their viral genomes suggests that they are related to the Icelandic and Japanese isolates. In addition, three virus particle morphologies that had not been previously observed from thermal environments were found. These viruses appear to be completely novel in nature.

Rice, George; Stedman, Kenneth; Snyder, Jamie; Wiedenheft, Blake; Willits, Debbie; Brumfield, Susan; McDermott, Timothy; Young, Mark J.

2001-01-01

172

Proteorhodopsin genes in giant viruses.  

PubMed

Viruses with large genomes encode numerous proteins that do not directly participate in virus biogenesis but rather modify key functional systems of infected cells. We report that a distinct group of giant viruses infecting unicellular eukaryotes that includes Organic Lake Phycodnaviruses and Phaeocystis globosa virus encode predicted proteorhodopsins that have not been previously detected in viruses. Search of metagenomic sequence data shows that putative viral proteorhodopsins are extremely abundant in marine environments. Phylogenetic analysis suggests that giant viruses acquired proteorhodopsins via horizontal gene transfer from proteorhodopsin-encoding protists although the actual donor(s) could not be presently identified. The pattern of conservation of the predicted functionally important amino acid residues suggests that viral proteorhodopsin homologs function as sensory rhodopsins. We hypothesize that viral rhodopsins modulate light-dependent signaling, in particular phototaxis, in infected protists. PMID:23036091

Yutin, Natalya; Koonin, Eugene V

2012-01-01

173

Classical swine fever virus replicon particles lacking the Erns gene: a potential marker vaccine for intradermal application.  

PubMed

Classical swine fever virus replicon particles (CSF-VRP) deficient for E(rns) were evaluated as a non-transmissible marker vaccine. A cDNA clone of CSFV strain Alfort/187 was used to obtain a replication-competent mutant genome (replicon) lacking the sequence encoding the 227 amino acids of the glycoprotein E(rns) (A187delE(rns)). For packaging of A187delE(rns) into virus particles, porcine kidney cell lines constitutively expressing E(rns) of CSFV were established. The rescued VRP were infectious in cell culture but did not yield infectious progeny virus. Single intradermal vaccination of two pigs with 10(7) TCID(50) of VRP A187delE(rns) elicited neutralizing antibodies, anti-E2 antibodies, and cellular immune responses determined by an increase of IFN-gamma producing cells. No anti-E(rns) antibodies were detected in the vaccinees confirming that this vaccine represents a negative marker vaccine allowing differentiation between infected and vaccinated animals. The two pigs were protected against lethal challenge with the highly virulent CSFV strain Eystrup. In contrast, oral immunization resulted in only partial protection, and neither CSFV-specific antibodies nor stimulated T-cells were found before challenge. These data represent a good basis for more extended vaccination/challenge trials including larger numbers of animals as well as more thorough analysis of virus shedding using sentinel animals to monitor horizontal spread of the challenge virus. PMID:16777037

Frey, Caroline F; Bauhofer, Oliver; Ruggli, Nicolas; Summerfield, Artur; Hofmann, Martin A; Tratschin, Jon-Duri

2006-01-01

174

Introducing Virological Concepts Using an Insect Virus.  

ERIC Educational Resources Information Center

A technique is presented which utilizes wax moth larvae in a laboratory investigation of an insect virus. Describes how an insect virus can be used to introduce undergraduate biology students to laboratory work on viruses and several virological concepts. (SA)

Sheppard, Roger F.

1980-01-01

175

Studies of Respiratory Syncytial Virus Vaccines.  

National Technical Information Service (NTIS)

Studies of Respiratory Syncytial virus vaccines included both biological and physical aspects with the principle objective being a study of the banding of RS virus in the density gradient ultracentrifuge. Various studies on virus propagation both in the B...

R. N. Hull C. B. Reimer L. F. Ellis

1966-01-01

176

NATIONAL RESPIRATORY AND ENTERIC VIRUS SURVEILLANCE SYSTEM  

EPA Science Inventory

The National Respiratory and Enteric Virus Surveillance System is a lab based system which monitors temporal and geographic patterns associated with the detection of respiratory syncytial virus (RSV), human parainfluenza viruses (HPIV), respiratory and enteric adenoviruses, and r...

177

Tobacco mosaic virus virulence and avirulence.  

PubMed Central

In celebration of a century of research on tobacco mosaic virus that initiated the science of virology, I review recent progress relative to earlier contributions concerning how viruses cause diseases of plants and how plants defend themselves from viruses.

Dawson, W O

1999-01-01

178

NIAID's Role in Addressing West Nile Virus  

MedlinePLUS

... repellants and other ways to prevent mosquito bites. World Reference Center for Emerging Viruses and Arboviruses (WRCEVA) ... virus when it replicates. NIAID also supports the World Reference Center for Emerging Viruses and Arboviruses (WRCEVA) , ...

179

Virus-Related Antigens Associated with Cancer.  

National Technical Information Service (NTIS)

Contents: Virus-associated antigens and human breast cancer; Virus-associated antigens and experimental mammary cancer; Viral antigens associated with leukemias and lymphomas; Cell surface and other virus-induced antigens associated with leukemias and lym...

1977-01-01

180

Equine arteritis virus.  

PubMed

Equine arteritis virus (EAV) is the causative agent of equine viral arteritis (EVA), a respiratory and reproductive disease of equids. There has been significant recent progress in understanding the molecular biology of EAV and the pathogenesis of its infection in horses. In particular, the use of contemporary genomic techniques, along with the development and reverse genetic manipulation of infectious cDNA clones of several strains of EAV, has generated significant novel information regarding the basic molecular biology of the virus. Therefore, the objective of this review is to summarize current understanding of EAV virion architecture, replication, evolution, molecular epidemiology and genetic variation, pathogenesis including the influence of host genetics on disease susceptibility, host immune response, and potential vaccination and treatment strategies. PMID:23891306

Balasuriya, Udeni B R; Go, Yun Young; MacLachlan, N James

2013-11-29

181

West Nile Virus  

PubMed Central

Overview Since its isolation in Uganda in 1937, West Nile virus (WNV) has been responsible for thousands of cases of morbidity and mortality in birds, horses, and humans. Historically, epidemics were localized to Europe, Africa, the Middle East, and parts of Asia, and primarily caused a mild febrile illness in humans. However, in the late 1990’s, the virus became more virulent and expanded its geographical range to North America. In humans, the clinical presentation ranges from asymptomatic (approximately 80% of infections) to encephalitis/paralysis and death (less than 1% of infections). There is no FDA-licensed vaccine for human use, and the only recommended treatment is supportive care. Individuals that survive infection often have a long recovery period. This article will review the current literature summarizing the molecular virology, epidemiology, clinical manifestations, pathogenesis, diagnosis, treatment, immunology, and protective measures against WNV and WNV infections in humans.

Rossi, Shannan L.; Ross, Ted M.; Evans, Jared D.

2010-01-01

182

The encephalomyocarditis virus  

PubMed Central

The encephalomyocarditis virus (EMCV) is a small non-enveloped single-strand RNA virus, the causative agent of not only myocarditis and encephalitis, but also neurological diseases, reproductive disorders and diabetes in many mammalian species. EMCV pathogenesis appears to be viral strain- and host-specific, and a better understanding of EMCV virulence factors is increasingly required. Indeed, EMCV is often used as a model for diabetes and viral myocarditis, and is also widely used in immunology as a double-stranded RNA stimulus in the study of Toll-like as well as cytosolic receptors. However, EMCV virulence and properties have often been neglected. Moreover, EMCV is able to infect humans albeit with a low morbidity. Progress on xenografts, such as pig heart transplantation in humans, has raised safety concerns that need to be explored. In this review we will highlight the biology of EMCV and all known and potential virulence factors.

Carocci, Margot; Bakkali-Kassimi, Labib

2012-01-01

183

Hetdex: Virus Instrument  

NASA Astrophysics Data System (ADS)

The Visible Integral-field-unit Replicable Unit Spectrograph (VIRUS) instrument is made up of 150+ individually compact and identical spectrographs, each fed by a fiber integral-field unit. The instrument provides integral field spectroscopy at wavelengths between 350nm and 550nm of over 33,600 spatial elements per observation, each 1.8 sq. arcsec on the sky, at R 700. The instrument will be fed by a new wide-field corrector (WFC) of the Hobby-Eberly Telescope (HET) with increased science field of view as large as 22arcmin diameter and telescope aperture of 10m. This will enable the HETDEX, a large area blind survey of Lyman-alpha emitting galaxies at redshift z < 3.5. The status of VIRUS instrument construction is summarized.

Lee, Hanshin; Hill, G. J.; DePoy, D. L.; Tuttle, S.; Marshall, J. L.; Vattiat, B. L.; Prochaska, T.; Chonis, T. S.; Allen, R.; HETDEX Collaboration

2012-01-01

184

Viruses from the Hypersaline Environment  

Microsoft Academic Search

\\u000a Halophilic environments such as solar salterns and salt lakes are enriched in organisms belonging to the domain Archaea. The\\u000a number of virus-like particles has also been shown to be high. Although most of the described haloarchaeal viruses are head–tail\\u000a viruses, direct microscopic examination of environmental samples suggests more diversity. In this chapter, we shortly review\\u000a the existing knowledge of the

Elina Roine; Hanna M. Oksanen

185

Reverse Genetics with Animal Viruses  

Microsoft Academic Search

New strategies to genetically manipulate the genomes of several important animal pathogens have been established in recent\\u000a years. This article focuses on the reverse genetics techniques, which enables genetic manipulation of the genomes of non-segmented\\u000a negative-sense RNA viruses. Recovery of a negative-sense RNA virus entirely from cDNA was first achieved for rabies virus\\u000a in 1994. Since then, reverse genetic systems

Teshome Mebatsion

186

Tracking the West Nile Virus  

NSDL National Science Digital Library

How can viral sequences help us establish the origin of the virus that appeared in the US in 1999? Epidemiologists have adopted bioinformatics approaches using sequence data from strains of pathogens to track the movement of bacteria and viruses from continent to continent. * explore a data set of West Nile Virus sequences from all over the world that date from the mid-20th century to the present

Erica Suchmann (University of California - San Diego;Biology); Mark Gallo (Niagara University;Biology)

2006-05-20

187

Viruses in extreme environments  

Microsoft Academic Search

The tolerance limits of extremophiles in term of temperature, pH, salinity, desiccation, hydrostatic pressure, radiation,\\u000a anaerobiosis far exceed what can support non-extremophilic organisms. Like all other organisms, extremophiles serve as hosts\\u000a for viral replication. Many lines of evidence suggest that viruses could no more be regarded as simple infectious “fragments\\u000a of life” but on the contrary as one of the

Marc Le Romancer; Mélusine Gaillard; Claire Geslin; Daniel Prieur

188

Human Immunodeficiency Virus  

Microsoft Academic Search

Oral health is an integral component of overall health and well-being in all patients. However, for an immunocompromised patient,\\u000a many common oral conditions may have a significant impact on quality of life. Intraoral pain, which is a common complaint\\u000a among patients with human immunodeficiency virus (HIV), will compromise patients’ ability to maintain adequate and appropriate\\u000a oral intake. Furthermore, the polypharmacopeia

Anita Patel; Michael Glick

189

Hepatitis delta virus.  

PubMed

Hepatitis delta virus (HDV) is a sub-viral agent that is dependent for its life cycle on hepatitis B virus (HBV). The help it obtains from HBV is limited to the sharing of envelope proteins. These proteins are needed to facilitate the assembly of the HDV genome into new virus particles, and in turn, to allow the attachment and entry of HDV into new host cells. In other respects, the replication of the small single-stranded circular RNA genome of HDV is independent of HBV. HDV genome replication produces two forms of a RNA-binding protein known as the long and small delta antigens (Ag). All other proteins needed for HDV genome replication, especially the RNA-directed RNA polymerase activity, are provided by the host cell. This mini-review article is a mixture of personal perspective and speculations about the future of HDV research. It starts with a brief overview of HDV and its replication, notes some of the major unresolved questions, and directs the interested reader to more detailed reviews. PMID:16364738

Taylor, John M

2006-01-01

190

STUDIES ON NEWCASTLE DISEASE VIRUS  

PubMed Central

1. It is likely that certain tailed and filamentous particles seen on electron microscope examination of partially purified saline suspensions of Newcastle virus are the individual virus particles because: (a) They have a highly characteristic shape not seen in other virus preparations. (b) They are present whenever the virus is present in high concentration. (c) Their size agrees with the size of the virus as calculated from light scattering and centrifuge data. (d) They are agglutinated by specific antisera. (e) Infection may be produced in the embryo by relatively few of these particles. 2. It is possible that these filamentous forms have been derived from spherical forms without loss of activity because: (a) Such filamentous forms are not found in the original allantoic fluid when this contains a comparable amount of virus. (b) Filamentous forms appeared in the original allantoic fluid when it was dialyzed against saline solution. (c) Filamentous forms were produced at certain hydrogen ion concentrations but not at others, in solutions maintaining the same infectivity for the embryo. (d) Spherical forms were obtained by suspending the partially purified virus in water instead of saline. In this the virus remained moderately stable. (e) These round forms could apparently be converted into tailed and filamentous forms by the addition of saline, again without loss of activity. (f) This "conversion" could be inhibited by partial inactivation of the water suspension of virus.

Bang, F. B.

1948-01-01

191

Structure of Flexible Filamentous Plant Viruses  

SciTech Connect

Flexible filamentous viruses make up a large fraction of the known plant viruses, but in comparison with those of other viruses, very little is known about their structures. We have used fiber diffraction, cryo-electron microscopy, and scanning transmission electron microscopy to determine the symmetry of a potyvirus, soybean mosaic virus; to confirm the symmetry of a potexvirus, potato virus X; and to determine the low-resolution structures of both viruses. We conclude that these viruses and, by implication, most or all flexible filamentous plant viruses share a common coat protein fold and helical symmetry, with slightly less than 9 subunits per helical turn.

Kendall, Amy; McDonald, Michele; Bian, Wen; Bowles, Timothy; Baumgarten, Sarah C.; Shi, Jian; Stewart, Phoebe L.; Bullitt, Esther; Gore, David; Irving, Thomas C.; Havens, Wendy M.; Ghabrial, Said A.; Wall, Joseph S.; Stubbs, Gerald (IIT); (BU-M); (Vanderbilt); (Kentucky); (BNL)

2008-10-23

192

Computer virus information update CIAC-2301  

SciTech Connect

While CIAC periodically issues bulletins about specific computer viruses, these bulletins do not cover all the computer viruses that affect desktop computers. The purpose of this document is to identify most of the known viruses for the MS-DOS and Macintosh platforms and give an overview of the effects of each virus. The authors also include information on some windows, Atari, and Amiga viruses. This document is revised periodically as new virus information becomes available. This document replaces all earlier versions of the CIAC Computer virus Information Update. The date on the front cover indicates date on which the information in this document was extracted from CIAC`s Virus database.

Orvis, W.J.

1994-01-15

193

Evolutionary relationship of alfalfa mosaic virus with cucumber mosaic virus and brome mosaic virus  

Microsoft Academic Search

The amino acid sequences of the non-structural protein (molecular weight 35,000; 3a protein) from three plant viruses — cucumber\\u000a mosaic, brome mosaic and alfalfa mosaic have been systematically compared using the partial genomic sequences for these three\\u000a viruses already available. The 3a protein of cucumber mosaic virus has an amino acid sequence homology of 33.7% with the corresponding\\u000a protein of

H. S. Savithri; M. R. N. Murthy

1983-01-01

194

Cowpea mosaic virus: the plant virus-based biotechnology workhorse.  

PubMed

In the 50 years since it was first described, Cowpea mosaic virus (CPMV) has become one of the most intensely studied plant viruses. Research in the past 15 to 20 years has shifted from studying the underlying genetics and structure of the virus to focusing on ways in which it can be exploited in biotechnology. This work led first to the use of virus particles to present peptides, then to the creation of a variety of replicating virus vectors and finally to the development of a highly efficient protein expression system that does not require viral replication. The circle has been completed by the use of the latter system to create empty particles for peptide presentation and other novel uses. The history of CPMV in biotechnology can be likened to an Ouroborus, an ancient symbol depicting a snake or dragon swallowing its own tail, thus forming a circle. PMID:20455698

Sainsbury, Frank; Cañizares, M Carmen; Lomonossoff, George P

2010-01-01

195

Hepatitis C Virus and Cardiomyopathy  

Microsoft Academic Search

The importance of hepatitis C virus infection has been recently noted in patients with hypertrophic cardiomyopathy or dilated cardiomyopathy. In a collaborative research project of the Committees for the Study of Idiopathic Cardiomyopathy, hepatitis C virus antibody was found in 74 of 697 patients (10.65) with hypertrophic cardiomyopathy and in 42 of 663 patients (6.3%) with dilated cardiomyopathy; these prevalences

Akira Matsumori

2000-01-01

196

Influenza virus assembly and budding.  

PubMed

Influenza A virus causes seasonal epidemics, sporadic pandemics and is a significant global health burden. Influenza virus is an enveloped virus that contains a segmented negative strand RNA genome. Assembly and budding of progeny influenza virions is a complex, multi-step process that occurs in lipid raft domains on the apical membrane of infected cells. The viral proteins hemagglutinin (HA) and neuraminidase (NA) are targeted to lipid rafts, causing the coalescence and enlargement of the raft domains. This clustering of HA and NA may cause a deformation of the membrane and the initiation of the virus budding event. M1 is then thought to bind to the cytoplasmic tails of HA and NA where it can then polymerize and form the interior structure of the emerging virion. M1, bound to the cytoplasmic tails of HA and NA, additionally serves as a docking site for the recruitment of the viral RNPs and may mediate the recruitment of M2 to the site of virus budding. M2 initially stabilizes the site of budding, possibly enabling the polymerization of the matrix protein and the formation of filamentous virions. Subsequently, M2 is able to alter membrane curvature at the neck of the budding virus, causing membrane scission and the release of the progeny virion. This review investigates the latest research on influenza virus budding in an attempt to provide a step-by-step analysis of the assembly and budding processes for influenza viruses. PMID:21237476

Rossman, Jeremy S; Lamb, Robert A

2011-03-15

197

Human viruses: discovery and emergence  

PubMed Central

There are 219 virus species that are known to be able to infect humans. The first of these to be discovered was yellow fever virus in 1901, and three to four new species are still being found every year. Extrapolation of the discovery curve suggests that there is still a substantial pool of undiscovered human virus species, although an apparent slow-down in the rate of discovery of species from different families may indicate bounds to the potential range of diversity. More than two-thirds of human viruses can also infect non-human hosts, mainly mammals, and sometimes birds. Many specialist human viruses also have mammalian or avian origins. Indeed, a substantial proportion of mammalian viruses may be capable of crossing the species barrier into humans, although only around half of these are capable of being transmitted by humans and around half again of transmitting well enough to cause major outbreaks. A few possible predictors of species jumps can be identified, including the use of phylogenetically conserved cell receptors. It seems almost inevitable that new human viruses will continue to emerge, mainly from other mammals and birds, for the foreseeable future. For this reason, an effective global surveillance system for novel viruses is needed.

Woolhouse, Mark; Scott, Fiona; Hudson, Zoe; Howey, Richard; Chase-Topping, Margo

2012-01-01

198

How Viruses Enter Animal Cells  

Microsoft Academic Search

Viruses replicate within living cells and use the cellular machinery for the synthesis of their genome and other components. To gain access, they have evolved a variety of elegant mechanisms to deliver their genes and accessory proteins into the host cell. Many animal viruses take advantage of endocytic pathways and rely on the cell to guide them through a complex

Alicia E. Smith; Ari Helenius

2004-01-01

199

Virioplankton: Viruses in Aquatic Ecosystems†  

PubMed Central

The discovery that viruses may be the most abundant organisms in natural waters, surpassing the number of bacteria by an order of magnitude, has inspired a resurgence of interest in viruses in the aquatic environment. Surprisingly little was known of the interaction of viruses and their hosts in nature. In the decade since the reports of extraordinarily large virus populations were published, enumeration of viruses in aquatic environments has demonstrated that the virioplankton are dynamic components of the plankton, changing dramatically in number with geographical location and season. The evidence to date suggests that virioplankton communities are composed principally of bacteriophages and, to a lesser extent, eukaryotic algal viruses. The influence of viral infection and lysis on bacterial and phytoplankton host communities was measurable after new methods were developed and prior knowledge of bacteriophage biology was incorporated into concepts of parasite and host community interactions. The new methods have yielded data showing that viral infection can have a significant impact on bacteria and unicellular algae populations and supporting the hypothesis that viruses play a significant role in microbial food webs. Besides predation limiting bacteria and phytoplankton populations, the specific nature of virus-host interaction raises the intriguing possibility that viral infection influences the structure and diversity of aquatic microbial communities. Novel applications of molecular genetic techniques have provided good evidence that viral infection can significantly influence the composition and diversity of aquatic microbial communities.

Wommack, K. Eric; Colwell, Rita R.

2000-01-01

200

Virus Removal by Chemical Coagulation.  

National Technical Information Service (NTIS)

Using bacterial viruses (Bacteriophages T4 and MS2 against Escherichia coli) as models and aluminum as the coagulant metal ion, it was shown that removal of viruses from water by chemical coagulation and flocculation with aluminum sulfate consists of a pr...

R. S. Engelbrecht M. Chaudhuri

1969-01-01

201

Sunshine virus in Australian pythons.  

PubMed

Sunshine virus is a recently discovered novel paramyxovirus that is associated with illness in snakes. It does not phylogenetically cluster within either of the two currently accepted paramyxoviral subfamilies. It is therefore only distantly related to the only other known genus of reptilian paramyxoviruses, Ferlavirus, which clusters within the Paramyxovirinae subfamily. Clinical and diagnostic aspects associated with Sunshine virus are as yet undescribed. The objective of this paper was to report the clinical presentation, virus isolation, PCR testing and pathology associated with Sunshine virus infection. Clinical records and samples from naturally occurring cases were obtained from two captive snake collections and the archives of a veterinary diagnostic laboratory. The clinical signs that are associated with Sunshine virus infection are localised to the neurorespiratory systems or are non-specific (e.g. lethargy, inappetence). Out of 15 snakes that were infected with Sunshine virus (detected in any organ by either virus isolation or PCR), the virus was isolated from four out of ten (4/10) sampled brains, 3/10 sampled lungs and 2/7 pooled samples of kidney and liver. In these same 15 snakes, PCR was able to successfully detect Sunshine virus in fresh-frozen brain (11/11), kidney (7/8), lung (8/11) and liver (5/8); and various formalin-fixed paraffin-embedded tissues (7/8). During a natural outbreak of Sunshine virus in a collection of 32 snakes, the virus could be detected in five out of 39 combined oral-cloacal swabs that were collected from 23 of these snakes over a 105 day period. All snakes that were infected with Sunshine virus were negative for reovirus and ferlavirus by PCR. Snakes infected with Sunshine virus reliably exhibited hindbrain white matter spongiosis and gliosis with extension to the surrounding grey matter and neuronal necrosis evident in severe cases. Five out of eight infected snakes also exhibited mild bronchointerstitial pneumonia. Infection with Sunshine virus should be considered by veterinarians investigating disease outbreaks in snakes, particularly those that are associated with neurorespiratory disease. PMID:22883310

Hyndman, Timothy H; Shilton, Cathy M; Doneley, Robert J T; Nicholls, Philip K

2012-12-28

202

Documenting Endangered Languages (DEL)  

NSF Publications Database

Full Proposal Preparation Instructions: This solicitation contains information that supplements the standard Grant Proposal Guide (GPG) proposal preparation guidelines. All DEL proposals for project grants and fellowships will receive specialist (ad hoc) and panel review within the NSF review process. More comprehensive information on NSF Award Conditions is contained in the NSF Grant Policy Manual (GPM) Chapter II, available electronically on the NSF Website at http://www.nsf.gov/...

203

Nevado del Huila, Columbia  

NASA Technical Reports Server (NTRS)

Nevado del Huila Volcano in Colombia is actually a volcanic chain running north to south, capped by a glacier. With peaks ranging in height from 2,600 to 5,780 meters (8,530 to 18,960 feet), Nevado del Huila is a stratovolcano composed of alternating layers of hardened lava, solidified ash, and volcanic rocks. Its first recorded eruption occurred in the mid-sixteenth century. The long-dormant volcano erupted again in mid-April 2007. A few months before the eruption, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured this image of Nevado del Huila, on February 23, 2007. In this image, the bright white area just east of the central summit is ice. Immediately west of the summit are bare rocks, appearing as blue-gray. West of those rocks, white reappears, but this patch of white results from clouds hovering in the nearby valley. In the east, the colors turn to brown (indicating bare rock) and bright green (indicating vegetation). ASTER photographed Nevado del Huila near the end of a long phase of quietude. On April 17, 2007, local authorities recorded seismic activity associated with rock fracturing on the volcano's central summit, according to the ReliefWeb Website. Activity intensified the following day with an eruption and mudflows, forcing thousands of nearby residents to evacuate. As the Associated Press reported, the eruption caused avalanches and floods that wiped away both houses and bridges. It marked the volcano's first recorded eruption since the Spanish colonized the area five centuries earlier. NASA image created by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.

2007-01-01

204

Marine Viruses: Truth or Dare  

NASA Astrophysics Data System (ADS)

Over the past two decades, marine virology has progressed from a curiosity to an intensely studied topic of critical importance to oceanography. At concentrations of approximately 10 million viruses per milliliter of surface seawater, viruses are the most abundant biological entities in the oceans. The majority of these viruses are phages (viruses that infect bacteria). Through lysing their bacterial hosts, marine phages control bacterial abundance, affect community composition, and impact global biogeochemical cycles. In addition, phages influence their hosts through selection for resistance, horizontal gene transfer, and manipulation of bacterial metabolism. Recent work has also demonstrated that marine phages are extremely diverse and can carry a variety of auxiliary metabolic genes encoding critical ecological functions. This review is structured as a scientific "truth or dare," revealing several well-established "truths" about marine viruses and presenting a few "dares" for the research community to undertake in future studies.

Breitbart, Mya

2012-01-01

205

Virus assembly, allostery, and antivirals  

PubMed Central

Assembly of virus capsids and surface proteins must be regulated to ensure that the resulting complex is an infectious virion. Here we examine assembly of virus capsids, focusing on hepatitis B virus and bacteriophage MS2, and formation of glycoproteins in the alphaviruses. These systems are structurally and biochemically well-characterized and are simplest-case paradigms of self-assembly. Published data suggest that capsid and glycoprotein assembly is subject to allosteric regulation, that is, regulation at the level of conformational change. The hypothesis that allostery is a common theme in viruses suggests that deregulation of capsid and glycoprotein assembly by small molecule effectors will be an attractive antiviral strategy, as has been demonstrated with hepatitis B virus.

Zlotnick, Adam; Mukhopadhyay, Suchetana

2010-01-01

206

Do viruses require the cytoskeleton?  

PubMed Central

Background It is generally thought that viruses require the cytoskeleton during their replication cycle. However, recent experiments in our laboratory with rubella virus, a member of the family Togaviridae (genus rubivirus), revealed that replication proceeded in the presence of drugs that inhibit microtubules. This study was done to expand on this observation. Findings The replication of three diverse viruses, Sindbis virus (SINV; family Togaviridae family), vesicular stomatitis virus (VSV; family Rhabdoviridae), and Herpes simplex virus (family Herpesviridae), was quantified by the titer (plaque forming units/ml; pfu/ml) produced in cells treated with one of three anti-microtubule drugs (colchicine, noscapine, or paclitaxel) or the anti-actin filament drug, cytochalasin D. None of these drugs affected the replication these viruses. Specific steps in the SINV infection cycle were examined during drug treatment to determine if alterations in specific steps in the virus replication cycle in the absence of a functional cytoskeletal system could be detected, i.e. redistribution of viral proteins and replication complexes or increases/decreases in their abundance. These investigations revealed that the observable impacts were a colchicine-mediated fragmentation of the Golgi apparatus and concomitant intracellular redistribution of the virion structural proteins, along with a reduction in viral genome and sub-genome RNA levels, but not double-stranded RNA or protein levels. Conclusions The failure of poisons affecting the cytoskeleton to inhibit the replication of a diverse set of viruses strongly suggests that viruses do not require a functional cytoskeletal system for replication, either because they do not utilize it or are able to utilize alternate pathways when it is not available.

2013-01-01

207

Infectious vaccinia virus recombinants that express hepatitis B virus surface antigen  

NASA Astrophysics Data System (ADS)

Potential live vaccines against hepatitis B virus have been produced. The coding sequence for hepatitis B virus surface antigen (HBsAg) has been inserted into the vaccinia virus genome under control of vaccinia virus early promoters. Cells infected with these vaccinia virus recombinants synthesize and excrete HBsAg and vaccinated rabbits rapidly produce antibodies to HBsAg.

Smith, Geoffrey L.; Mackett, Michael; Moss, Bernard

1983-04-01

208

Comparison CCR5del32 Mutation in the CCR5 Gene Frequencies in Russians, Tuvinians, and in Groups of HIV-Infected Individuals  

Microsoft Academic Search

The 32-bp deletion (CCR5del32 mutation) in the CCR5 (chemokine (C-C motif) receptor 5) gene, encoding CCR5 chemokine receptor, is one of the factors determining natural resistance\\u000a to human immunodeficiency virus (HIV-1) infection. In the present study, the samples of Russians (n = 102), Tuvinians (n = 50), and HIV-infected individuals (n = 107) were examined for the presence of CCR5del32

S. A. Apryatin; E. R. Rakhmanaliev; I. A. Nikolaeva; S. V. Ruban; F. G. Vazykhova; E. A. Klimov; G. E. Sulimova; I. G. Sidorovich

2005-01-01

209

The Acute bee paralysis virus-Kashmir bee virus-Israeli acute paralysis virus complex.  

PubMed

Acute bee paralysis virus (ABPV), Kashmir bee virus (KBV) and Israeli acute paralysis virus (IAPV) are part of a complex of closely related viruses from the Family Dicistroviridae. These viruses have a widespread prevalence in honey bee (Apis mellifera) colonies and a predominantly sub-clinical etiology that contrasts sharply with the extremely virulent pathology encountered at elevated titres, either artificially induced or encountered naturally. These viruses are frequently implicated in honey bee colony losses, especially when the colonies are infested with the parasitic mite Varroa destructor. Here we review the historical and recent literature of this virus complex, covering history and origins; the geographic, host and tissue distribution; pathology and transmission; genetics and variation; diagnostics, and discuss these within the context of the molecular and biological similarities and differences between the viruses. We also briefly discuss three recent developments relating specifically to IAPV, concerning its association with Colony Collapse Disorder, treatment of IAPV infection with siRNA and possible honey bee resistance to IAPV. PMID:19909972

de Miranda, Joachim R; Cordoni, Guido; Budge, Giles

2010-01-01

210

Influenza: a virus of our times  

PubMed Central

Viruses are successful and omnipresent. Influenza A is a particularly important virus of humans. The article reviews the 2009 emergence of the pandemic influenza A virus, focusing on the potential origin of the virus and the distinctive clinical and epidemiological impact of the 2009 pandemic.

McCaughey, Conall

2010-01-01

211

Immunogenicity of combination DNA vaccines for Rift Valley fever virus, tick-borne encephalitis virus, Hantaan virus, and Crimean Congo hemorrhagic fever virus  

Microsoft Academic Search

DNA vaccines for Rift Valley fever virus (RVFV), Crimean Congo hemorrhagic fever virus (CCHFV), tick-borne encephalitis virus (TBEV), and Hantaan virus (HTNV), were tested in mice alone or in various combinations. The bunyavirus vaccines (RVFV, CCHFV, and HTNV) expressed Gn and Gc genes, and the flavivirus vaccine (TBEV) expressed the preM and E genes. All vaccines were delivered by gene

Kristin Spik; Amy Shurtleff; Anita K. McElroy; Mary C. Guttieri; Jay W. Hooper; Connie Schmaljohn

2006-01-01

212

Biologically Inspired Defenses Against Computer Viruses  

Microsoft Academic Search

Today's anti-virus technology, based largely on analysis of existing viruses by human experts, is just barely able to keep pace with the more than three new computer viruses that are writ­ ten daily. In a few years, intelligent agents nav­ igating through highly connected networks are likely to form an extremely fertile medium for a new breed of viruses. At

Jeffrey O. Kephart; Gregory B. Sorkin; William C. Arnold; David M. Chess; Gerald Tesauro; Steve R. White

1995-01-01

213

Safe Computing: An Overview of Viruses.  

ERIC Educational Resources Information Center

A computer virus is a program that replicates itself, in conjunction with an additional program that can harm a computer system. Common viruses include boot-sector, macro, companion, overwriting, and multipartite. Viruses can be fast, slow, stealthy, and polymorphic. Anti-virus products are described. (MLH)

Wodarz, Nan

2001-01-01

214

Smallpox vaccination and bioterrorism with pox viruses  

Microsoft Academic Search

Bioterrorist attacks occupy a special place amongst the innumerable potential types of terrorist attack, with the intentional release of pox viruses being especially feared in this connection. Apart from the variola virus, the agent responsible for smallpox in humans, the monkeypox virus and numerous other animal pox viruses pose potential risks for humans and animals. This risk scenario also includes

Anton Mayr

2003-01-01

215

Hepatitis E virus infection.  

PubMed

Hepatitis E virus (HEV) infection is a worldwide disease. An improved understanding of the natural history of HEV infection has been achieved within the last decade. Several reservoirs and transmission modes have been identified. Hepatitis E is an underdiagnosed disease, in part due to the use of serological assays with low sensitivity. However, diagnostic tools, including nucleic acid-based tests, have been improved. The epidemiology and clinical features of hepatitis E differ between developing and developed countries. HEV infection is usually an acute self-limiting disease, but in developed countries it causes chronic infection with rapidly progressive cirrhosis in organ transplant recipients, patients with hematological malignancy requiring chemotherapy, and individuals with HIV. HEV also causes extrahepatic manifestations, including a number of neurological syndromes and renal injury. Acute infection usually requires no treatment, but chronic infection should be treated by reducing immunosuppression in transplant patients and/or the use of antiviral therapy. In this comprehensive review, we summarize the current knowledge about the virus itself, as well as the epidemiology, diagnostics, natural history, and management of HEV infection in developing and developed countries. PMID:24396139

Kamar, Nassim; Dalton, Harry R; Abravanel, Florence; Izopet, Jacques

2014-01-01

216

Hepatitis E virus.  

PubMed

Hepatitis E virus (HEV) is responsible for major outbreaks of acute hepatitis in developing countries where it was first described as a waterborne disease, transmitted by drinking water contaminated with feces. Attention was focused on HEV in developed countries and its associated diseases in recent years as a result of increasing reports of autochthonous infections. Hepatitis E is the zoonotic cause of these acute infections, and mainly in men over 50 years of age. The clinical manifestations and laboratory abnormalities of hepatitis E infections in immunocompetent patients cannot be distinguished from those caused by other hepatitis viruses. HEV is a major public health concern in immunocompromised patients because their infections can become chronic. The specific etiology of cases of hepatitis E infection can be diagnosed by serological testing and detecting viral RNA. Ribavirin is currently the reference treatment for HEV infections in immunocompromised patients. Several vaccines have proved safe and effective in clinical trials, but none have been approved for use in Europe yet. PMID:23608595

Abravanel, F; Lhomme, S; Dubois, M; Peron, J-M; Alric, L; Kamar, N; Izopet, J

2013-07-01

217

Virus interactions with human signal transduction pathways  

PubMed Central

Viruses depend on their hosts at every stage of their life cycles and must therefore communicate with them via Protein-Protein Interactions (PPIs). To investigate the mechanisms of communication by different viruses, we overlay reported pairwise human-virus PPIs on human signalling pathways. Of 671 pathways obtained from NCI and Reactome databases, 355 are potentially targeted by at least one virus. The majority of pathways are linked to more than one virus. We find evidence supporting the hypothesis that viruses often interact with different proteins depending on the targeted pathway. Pathway analysis indicates overrepresentation of some pathways targeted by viruses. The merged network of the most statistically significant pathways shows several centrally located proteins, which are also hub proteins. Generally, hub proteins are targeted more frequently by viruses. Numerous proteins in virus-targeted pathways are known drug targets, suggesting that these might be exploited as potential new approaches to treatments against multiple viruses.

Zhao, Zhongming; Xia, Junfeng; Tastan, Oznur; Singh, Irtisha; Kshirsagar, Meghana; Carbonell, Jaime; Klein-Seetharaman, Judith

2011-01-01

218

Transmitting Plant Viruses Using Whiteflies  

PubMed Central

Whiteflies, Hemiptera: Aleyrodidae, Bemisia tabaci, a complex of morphologically indistinquishable species5, are vectors of many plant viruses. Several genera of these whitefly-transmitted plant viruses (Begomovirus, Carlavirus, Crinivirus, Ipomovirus, Torradovirus) include several hundred species of emerging and economically significant pathogens of important food and fiber crops (reviewed by9,10,16). These viruses do not replicate in their vector but nevertheless are moved readily from plant to plant by the adult whitefly by various means (reviewed by2,6,7,9,10,11,17). For most of these viruses whitefly feeding is required for acquisition and inoculation, while for others only probing is required. Many of these viruses are unable or cannot be easily transmitted by other means. Therefore maintenance of virus cultures, biological and molecular characterization (identification of host range and symptoms)3,13, ecology2,12, require that the viruses be transmitted to experimental hosts using the whitefly vector. In addition the development of new approaches to management, such as evaluation of new chemicals14 or compounds15, new cultural approaches1,4,19, or the selection and development of resistant cultivars7,8,18, requires the use of whiteflies for virus transmission. The use of whitefly transmission of plant viruses for the selection and development of resistant cultivars in breeding programs is particularly challenging7. Effective selection and screening for resistance employs large numbers of plants and there is a need for 100% of the plants to be inoculated in order to find the few genotypes which possess resistance genes. These studies use very large numbers of viruliferous whiteflies, often several times per year. Whitefly maintenance described here can generate hundreds or thousands of adult whiteflies on plants each week, year round, without the contamination of other plant viruses. Plants free of both whiteflies and virus must be produced to introduce into the whitefly colony each week. Whitefly cultures must be kept free of whitefly pathogens, parasites, and parasitoids that can reduce whitefly populations and/or reduce the transmission efficiency of the virus. Colonies produced in the manner described can be quickly scaled to increase or decrease population numbers as needed, and can be adjusted to accommodate the feeding preferences of the whitefly based on the plant host of the virus. There are two basic types of whitefly colonies that can be maintained: a nonviruliferous and a viruliferous whitefly colony. The nonviruliferous colony is composed of whiteflies reared on virus-free plants and allows the weekly availability of whiteflies which can be used to transmit viruses from different cultures. The viruliferous whitefly colony, composed of whiteflies reared on virus-infected plants, allows weekly availability of whiteflies which have acquired the virus thus omitting one step in the virus transmission process.

Polston, Jane E.; Capobianco, H.

2013-01-01

219

Viruses and Interactomes in Translation*  

PubMed Central

A decade of high-throughput screenings for intraviral and virus-host protein-protein interactions led to the accumulation of data and to the development of theories on laws governing interactome organization for many viruses. We present here a computational analysis of intraviral protein networks (EBV, FLUAV, HCV, HSV-1, KSHV, SARS-CoV, VACV, and VZV) and virus-host protein networks (DENV, EBV, FLUAV, HCV, and VACV) from up-to-date interaction data, using various mathematical approaches. If intraviral networks seem to behave similarly, they are clearly different from the human interactome. Viral proteins target highly central human proteins, which are precisely the Achilles' heel of the human interactome. The intrinsic structural disorder is a distinctive feature of viral hubs in virus-host interactomes. Overlaps between virus-host data sets identify a core of human proteins involved in the cellular response to viral infection and in the viral capacity to hijack the cell machinery for viral replication. Host proteins that are strongly targeted by a virus seem to be particularly attractive for other viruses. Such protein-protein interaction networks and their analysis represent a powerful resource from a therapeutic perspective.

Meyniel-Schicklin, Laurene; de Chassey, Benoit; Andre, Patrice; Lotteau, Vincent

2012-01-01

220

21 CFR 866.3360 - Lymphocytic choriomeningitis virus serological reagents.  

Code of Federal Regulations, 2013 CFR

... false Lymphocytic choriomeningitis virus serological reagents. 866.3360 Section...866.3360 Lymphocytic choriomeningitis virus serological reagents. (a) Identification. Lymphocytic choriomeningitis virus serological reagents are devices...

2013-04-01

221

Influenza Viruses in Animal Wildlife Populations  

Microsoft Academic Search

Influenza viruses belong to the family Orthomyxoviridae. Genus Influenza A viruses are true zoonotic agents with many animal reservoirs, whereas genus Influenza B viruses are generally\\u000a considered to be a virus of humans. The genome of influenza A viruses consists of eight unique segments of single-stranded\\u000a RNA of negative polarity; they are typed according to their surface proteins, hemagglutinin (HA)

R. J. Webby; R. G. Webster; Jürgen A. Richt

222

Fish Viruses: A Double-Stranded RNA Icosahedral Virus from a North American Cyprinid.  

National Technical Information Service (NTIS)

A previously unreported virus disease of cultured golden shiners (Notemigonus crysoleucas) is described. The condition is called golden shiner virus (GSV) disease. The virus is icosahedral, measures approximately 70 nm, is ether and heat resistant, stable...

J. A. Plumb P. R. Bowser J. M. Grizzle A. J. Mitchell

1978-01-01

223

78 FR 29755 - Human Immunodeficiency Virus Patient-Focused Drug Development and Human Immunodeficiency Virus...  

Federal Register 2010, 2011, 2012, 2013

...FDA-2013-N-0473] Human Immunodeficiency Virus Patient-Focused Drug Development and Human Immunodeficiency Virus...for public comment on human immunodeficiency virus...Patient-Focused Drug Development and HIV Cure...

2013-05-21

224

78 FR 46969 - Human Immunodeficiency Virus Patient-Focused Drug Development and Human Immunodeficiency Virus...  

Federal Register 2010, 2011, 2012, 2013

...FDA-2013-N-0473] Human Immunodeficiency Virus Patient-Focused Drug Development and Human Immunodeficiency Virus...meeting entitled ``Human Immunodeficiency Virus...Patient-Focused Drug Development and HIV Cure...

2013-08-02

225

9 CFR 113.215 - Bovine Virus Diarrhea Vaccine, Killed Virus.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 2009-01-01 false Bovine Virus Diarrhea Vaccine, Killed Virus. 113.215 Section 113.215 Animals and...INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS;...

2009-01-01

226

Virus infection and knee injury.  

PubMed Central

Serological evidence of virus infection was sought in 31 consecutive patients presenting with knee swelling and compared with age/sex-matched controls. In a normal age/sex-matched control group, 42% of patients had evidence of recent or past infection with Coxsackie B virus, emphasising the care required in the evaluation of the significance of Coxsackie B neutralization titres in individual patients. Of 12 patients presenting with knee swelling and a history of a twisting injury, eight had serological evidence of recent or past infection with Coxsackie B virus, and one had evidence of a current adenovirus infection.

Driscoll, P; Venner, R; Clements, G B

1987-01-01

227

Model for Vesicular Stomatitis Virus  

PubMed Central

Vesicular stomatitis virus contains single-stranded ribonucleic acid of molecular weight 3.6 × 106 and three major proteins with molecular weights of 75 × 103, 57 × 103, and 32.5 × 103. The proteins have been shown to be subunits of the surface projections, ribonucleoprotein, and matrix protein, respectively. From these values and from estimates of the proportions of the individual proteins, it has been calculated that the virus has approximately 500 surface projections, 1,100 protein units on the ribonucleoprotein strand, and 1,600 matrix protein units. Possible models of the virus are proposed in which the proteins are interrelated. Images

Cartwright, B.; Smale, C. J.; Brown, F.; Hull, R.

1972-01-01

228

New genotypes of white spot syndrome virus (WSSV) and Taura syndrome virus (TSV) from the Kingdom of Saudi Arabia.  

PubMed

White spot syndrome virus (WSSV) and Taura syndrome virus (TSV) are highly pathogenic to penaeid shrimp and have caused significant economic losses in the shrimp culture industry around the world. During 2010 and 2011, both WSSV and TSV were found in Saudi Arabia, where they caused severe mortalities in cultured Indian white shrimp Penaeus indicus. Most outbreaks of shrimp viruses in production facilities can be traced to the importation of infected stocks or commodity shrimp. In an attempt to determine the origins of these viral outbreaks in Saudi Arabia, we performed variable number of tandem repeat (VNTR) analyses for WSSV isolates and a phylogenetic analysis for TSV isolates. From the WSSV genome, the VNTR in open reading frames (ORFs) 125 and 94 were investigated with PCR followed by DNA sequence analysis. The genotypes were categorized as {N125, N94} where N is the number of repeat units in a specific ORF, and the subscript indicates the ORF (i.e. ORFs 125 and 94 in this case). From 15 Saudi Arabia WSSV isolates, we detected 3 genotypes: {6125, 794}, {7125, del94}, and {8125, 1394}. The WSSV genotype of {7125, del94} appears to be a new variant with a 1522 bp deletion encompassing complete coding regions of ORF 94 and ORF 95 and the first 82 bp of ORF 93. For TSV genotyping, we used a phylogenetic analysis based on the amino acid sequence of TSV capsid protein 2 (CP2). We analyzed 8 Saudi Arabian isolates in addition to 36 isolates from other areas: SE Asia, Mexico, Venezuela and Belize. The Saudi Arabian TSV clustered into a new, distinct group. Based on these genotyping analyses, new WSSV and TSV genotypes were found in Saudi Arabia. The data suggest that they have come from wild shrimp Penaeus indicus from the Red Sea that are used for broodstock. PMID:22832716

Tang, Kathy F J; Navarro, Solangel A; Pantoja, Carlos R; Aranguren, Fernando L; Lightner, Donald V

2012-07-25

229

Xenotropic Murine Leukemia Virus-related Virus (XMRV) Backgrounder  

Cancer.gov

Researchers have not found evidence that XMRV causes any diseases in humans or in animals. The presence of an infectious agent, such as a virus, in diseased tissue does not mean that the agent causes the disease.

230

Boletín del Instituto Nacional del Cáncer - 02-02-2010  

Cancer.gov

En un estudio clínico en fase inicial que probó una vacuna terapéutica en pacientes con leucemia mieloide crónica (LMC) que tomaban el fármaco imatinib (Gleevec), no se pudieron detectar células cancerosas en 7 de los 19 participantes por un tiempo promedio de 22 meses. Los resultados del estudio fueron publicados en el número del 1º de enero de la revista Clinical Cancer Research.

231

Evolution of Computer Virus Concealment and AntiVirus Techniques: A Short Survey  

Microsoft Academic Search

This paper presents a general overview on evolution of concealment methods in computer viruses and defensive techniques employed by anti-virus products. In order to stay far from the anti-virus scanners, computer viruses gradually improve their codes to make them invisible. On the other hand, anti-virus technologies continually follow the virus tricks and methodologies to overcome their threats. In this process,

Babak Bashari Rad; Maslin Masrom; Suhaimi Ibrahim

2011-01-01

232

Antiviral Drugs for Viruses Other Than Human Immunodeficiency Virus  

PubMed Central

Most viral diseases, with the exception of those caused by human immunodeficiency virus, are self-limited illnesses that do not require specific antiviral therapy. The currently available antiviral drugs target 3 main groups of viruses: herpes, hepatitis, and influenza viruses. With the exception of the antisense molecule fomivirsen, all antiherpes drugs inhibit viral replication by serving as competitive substrates for viral DNA polymerase. Drugs for the treatment of influenza inhibit the ion channel M2 protein or the enzyme neuraminidase. Combination therapy with Interferon-? and ribavirin remains the backbone treatment for chronic hepatitis C; the addition of serine protease inhibitors improves the treatment outcome of patients infected with hepatitis C virus genotype 1. Chronic hepatitis B can be treated with interferon or a combination of nucleos(t)ide analogues. Notably, almost all the nucleos(t) ide analogues for the treatment of chronic hepatitis B possess anti–human immunodeficiency virus properties, and they inhibit replication of hepatitis B virus by serving as competitive substrates for its DNA polymerase. Some antiviral drugs possess multiple potential clinical applications, such as ribavirin for the treatment of chronic hepatitis C and respiratory syncytial virus and cidofovir for the treatment of cytomegalovirus and other DNA viruses. Drug resistance is an emerging threat to the clinical utility of antiviral drugs. The major mechanisms for drug resistance are mutations in the viral DNA polymerase gene or in genes that encode for the viral kinases required for the activation of certain drugs such as acyclovir and ganciclovir. Widespread antiviral resistance has limited the clinical utility of M2 inhibitors for the prevention and treatment of influenza infections. This article provides an overview of clinically available antiviral drugs for the primary care physician, with a special focus on pharmacology, clinical uses, and adverse effects.

Razonable, Raymund R.

2011-01-01

233

Antiviral drugs for viruses other than human immunodeficiency virus.  

PubMed

Most viral diseases, with the exception of those caused by human immunodeficiency virus, are self-limited illnesses that do not require specific antiviral therapy. The currently available antiviral drugs target 3 main groups of viruses: herpes, hepatitis, and influenza viruses. With the exception of the antisense molecule fomivirsen, all antiherpes drugs inhibit viral replication by serving as competitive substrates for viral DNA polymerase. Drugs for the treatment of influenza inhibit the ion channel M(2) protein or the enzyme neuraminidase. Combination therapy with Interferon-? and ribavirin remains the backbone treatment for chronic hepatitis C; the addition of serine protease inhibitors improves the treatment outcome of patients infected with hepatitis C virus genotype 1. Chronic hepatitis B can be treated with interferon or a combination of nucleos(t)ide analogues. Notably, almost all the nucleos(t) ide analogues for the treatment of chronic hepatitis B possess anti-human immunodeficiency virus properties, and they inhibit replication of hepatitis B virus by serving as competitive substrates for its DNA polymerase. Some antiviral drugs possess multiple potential clinical applications, such as ribavirin for the treatment of chronic hepatitis C and respiratory syncytial virus and cidofovir for the treatment of cytomegalovirus and other DNA viruses. Drug resistance is an emerging threat to the clinical utility of antiviral drugs. The major mechanisms for drug resistance are mutations in the viral DNA polymerase gene or in genes that encode for the viral kinases required for the activation of certain drugs such as acyclovir and ganciclovir. Widespread antiviral resistance has limited the clinical utility of M(2) inhibitors for the prevention and treatment of influenza infections. This article provides an overview of clinically available antiviral drugs for the primary care physician, with a special focus on pharmacology, clinical uses, and adverse effects. PMID:21964179

Razonable, Raymund R

2011-10-01

234

Adeno-associated virus: from defective virus to effective vector  

PubMed Central

The initial discovery of adeno-associated virus (AAV) mixed with adenovirus particles was not a fortuitous one but rather an expression of AAV biology. Indeed, as it came to be known, in addition to the unavoidable host cell, AAV typically needs a so-called helper virus such as adenovirus to replicate. Since the AAV life cycle revolves around another unrelated virus it was dubbed a satellite virus. However, the structural simplicity plus the defective and non-pathogenic character of this satellite virus caused recombinant forms to acquire centre-stage prominence in the current constellation of vectors for human gene therapy. In the present review, issues related to the development of recombinant AAV (rAAV) vectors, from the general principle to production methods, tropism modifications and other emerging technologies are discussed. In addition, the accumulating knowledge regarding the mechanisms of rAAV genome transduction and persistence is reviewed. The topics on rAAV vectorology are supplemented with information on the parental virus biology with an emphasis on aspects that directly impact on vector design and performance such as genome replication, genetic structure, and host cell entry.

Goncalves, Manuel AFV

2005-01-01

235

Adeno-associated virus: from defective virus to effective vector.  

PubMed

The initial discovery of adeno-associated virus (AAV) mixed with adenovirus particles was not a fortuitous one but rather an expression of AAV biology. Indeed, as it came to be known, in addition to the unavoidable host cell, AAV typically needs a so-called helper virus such as adenovirus to replicate. Since the AAV life cycle revolves around another unrelated virus it was dubbed a satellite virus. However, the structural simplicity plus the defective and non-pathogenic character of this satellite virus caused recombinant forms to acquire centre-stage prominence in the current constellation of vectors for human gene therapy. In the present review, issues related to the development of recombinant AAV (rAAV) vectors, from the general principle to production methods, tropism modifications and other emerging technologies are discussed. In addition, the accumulating knowledge regarding the mechanisms of rAAV genome transduction and persistence is reviewed. The topics on rAAV vectorology are supplemented with information on the parental virus biology with an emphasis on aspects that directly impact on vector design and performance such as genome replication, genetic structure, and host cell entry. PMID:15877812

Gonçalves, Manuel A F V

2005-01-01

236

Human immunodeficiency virus endocrinopathy  

PubMed Central

Human immunodeficiency virus (HIV) endocrinopathy encompasses a broad spectrum of disorders. Almost all the endocrine organs are virtually affected by HIV infection. HIV can directly alter glandular function. More commonly secondary endocrine dysfunction occurs due to opportunistic infections and neoplasms in immunocompromised state. The complex interaction between HIV infection and endocrine system may be manifested as subtle biochemical and hormonal perturbation to overt glandular failure. Antiretroviral therapy as well as other essential medications often result in adverse endocrinal consequences. Apart from adrenal insufficiency, hypogonadism, diabetes and bone loss, AIDS wasting syndrome and HIV lipodystrophy need special reference. Endocrinal evaluation should proceed as in other patients with suspected endocrine dysfunction. Available treatment options have been shown to improve quality of life and long-term mortality in AIDS patients.

Sinha, Uma; Sengupta, Nilanjan; Mukhopadhyay, Prasanta; Roy, Keshab Sinha

2011-01-01

237

Hepatitis C virus kinetics.  

PubMed

The balance of virus production and clearance for untreated patients with chronic hepatitis C virus (HCV) results in a decline of viraemia when initiating active antiviral treatment. During the first phase of interferon-alpha therapy, after a delay of about 8-9 h, the kinetics of the viral load is characterized by a rapid dose-dependent decline. This early response can be observed for almost all patients treated with interferon-alpha. After about 24-48 h, the viral decline enters a second phase of relatively slow exponential decay during the following weeks of therapy. Non-responding patients, however, show constant viraemia or even a rebound during this second phase. The rate of the exponential decline of the viral load in responding patients in this second phase is less sensitive to the dose of interferon-alpha and varies considerably among patients. Furthermore, combination therapy with interferon-alpha plus ribavirin does not significantly improve the initial viral decay, although it may prevent more patients from rebounding. Mathematical modelling of viral dynamics reveals high turnover rates of pre-treatment viral production and clearance, and permits the estimation of in vivo half-lives of a few hours for free HCV virions and of 1-70 days for productively infected cells. Infected cell death rate, which determines the second phase decline slope, is predictive of response to treatment. Current models indicate that the early biphasic viral decline is explained if interferon-alpha partially blocks virion production from infected cells, yet they do not rule out additional antiviral or immunological effects. Therapeutic implications are the advisability of use of frequent (daily) and comparatively high initial doses. In conclusion, kinetic analysis of the viral decay during the first weeks of treatment permits the prediction of response at the end-of-therapy and might help to evaluate new drugs and to optimize therapy. PMID:10971860

Herrmann, E; Neumann, A U; Schmidt, J M; Zeuzem, S

2000-06-01

238

[An update on Lassa virus].  

PubMed

Lassa virus, the etiologic agent of Lassa hemorrhagic fever, infects 100,000 to 300,000 people every year in West Africa with an overall mortality rate ranging from 1 to 2%. It was discovered in 1969 and remains a significant public health risk in endemic areas. Because airborne transmission is possible and mortality can be high under certain conditions, Lassa virus has been classified as a category A bioterrorism agent. Early diagnosis is difficult due to insidious non-specific onset and to the great genetic divergence of the virus that makes RT-PCR assays unreliable. The lack of proper diagnostic tools promotes nosocomial infection and diminishes the efficacy of treatment. Recently, numerous advances have been made in the development of both diagnostic and vaccination techniques. The purpose of this review is to present an update on that research as well as the current epidemiology of Lassa virus. PMID:22393616

Leparc-Goffart, I; Emonet, S F

2011-12-01

239

Virus Transport through Solid Beds.  

National Technical Information Service (NTIS)

A theoretical model for predicting the breakthrough curve of viruses from solid beds is developed. This model includes the percolation of contaminated water through clean solid beds (saturation) and of uncontaminated water through contaminated beds (eluti...

S. Sundaram

1977-01-01

240

Novel vaccines against influenza viruses  

PubMed Central

Killed and live attenuated influenza virus vaccines are effective in preventing and curbing the spread of influenza epidemics when the strains present in the vaccines are closely matched with the predicted epidemic strains. These vaccines are primarily targeted to induce immunity to the variable major target antigen, hemagglutinin (HA) of influenza virus. However, current vaccines are not effective in preventing the emergence of new pandemic or highly virulent viruses. New approaches are being investigated to develop universal influenza virus vaccines as well as to apply more effective vaccine delivery methods. Conserved vaccine targets including the influenza M2 ion channel protein and HA stalk domains are being developed using recombinant technologies to improve the level of cross protection. In addition, recent studies provide evidence that vaccine supplements can provide avenues to further improve current vaccination.

Kang, Sang-Moo; Song, Jae-Min; Compans, Richard W.

2011-01-01

241

Viruses of eukaryotice green algae  

SciTech Connect

The primary objective of our research was to develop the Chlorella-PBCV-1 virus system so that it can be used as a model system for studying gene expression in a photosynthetic eukaryote. We have made considerable progress and have learned much about PBCV-1 and its replication cycle. In addition, several significant discoveries were made in the last 3 to 4 years. These discoveries include: (i) the finding that morphologically similar, plaque forming, dsDNA containing viruses are common in nature and can be isolated readily from fresh water, (ii) the finding that all of these Chlorella viruses contain methylated bases which range in concentration from 0.1% to 47.5% m{sup 5}dC and 0 to 37% m{sup 6}dA and (iii) the discovery that infection with at least some of these viruses induces the appearance of DNA modification/restriction systems. 26 refs.

Van Etten, J.L.

1989-01-01

242

Respiratory Syncytial Virus Infection Disrupts Monolayer Integrity and Function in Cystic Fibrosis Airway Cells  

PubMed Central

Background: Respiratory Syncytial Virus (RSV) infection is a common contributor to pulmonary symptoms in children with cystic fibrosis (CF). Here we examined RSV infection in immortalized bronchial epithelial cells (CFBE41o-) expressing wild-type (wt) or F508del cystic fibrosis transmembrane conductance regulator (CFTR), for monolayer integrity and RSV replication. Methods: CFBE41o- monolayers expressing wt or F508del CFTR were grown on permeable supports and inoculated with RSV A2 strain. Control experiments utilized UV-inactivated RSV and heat-killed RSV. Monolayer resistance and RSV production was monitored for up to six days post-infection. Results: Within 24 h, a progressive decrease in monolayer resistance was observed in RSV infected F508del CFBE41o- cells, while the monolayer integrity of RSV infected wt CFTR CFBE41o- cells remained stable. RSV replication was necessary to disrupt F508del CFBE41o- monolayers as UV-irradiated and heat killed RSV had no effect on monolayer integrity, with an earlier and much more pronounced peak in RSV titer noted in F508del relative to wt CFTR-expressing cells. RSV infection of wt CFBE41o- monolayers also resulted in blunting of CFTR response. Conclusions: These findings identify an enhanced sensitivity of CFBE41o- cells expressing F508del CFTR to RSV infection, replication and monolayer disruption independent of the cellular immune response, and provide a novel mechanism by which cystic fibrosis airway epithelia are susceptible to RSV-dependent injury.

Michele, Kong; Patrick, Maeng; Jeong, Hong; Rhonda, Szczesniak; Eric, Sorscher; Wayne, Sullender; John Paul, Clancy

2013-01-01

243

Coronavirus avian infectious bronchitis virus  

Microsoft Academic Search

Infectious bronchitis virus (IBV), the coronavirus of the chicken (Gallus gallus), is one of the foremost causes of economic loss within the poultry industry, affecting the performance of both meat-type and egg-laying birds. The virus replicates not only in the epithelium of upper and lower respiratory tract tissues, but also in many tissues along the alimentary tract and elsewhere e.g.

Dave Cavanagh

2007-01-01

244

Movement of Viruses between Biomes  

Microsoft Academic Search

Viruses are abundant in all known ecosystems. In the present study, we tested the possibility that viruses from one biome can successfully propagate in another. Viral concentrates were prepared from different near-shore marine sites, lake water, marine sediments, and soil. The concentrates were added to microcosms containing dissolved organic matter as a food source (after filtration to allow 100-kDa particles

Emiko Sano; Suzanne Carlson; Linda Wegley; Forest Rohwer

2004-01-01

245

Membrane Proteins in Plant Viruses  

Microsoft Academic Search

It is clear that MPs play an essential role in the pathogenesis and movement within the plant of many plant viruses. However,\\u000a studies of the structure and function of such proteins are still in their infancy. Substantial progress may be expected in\\u000a the next few years, particularly in the area of cell-to-cell movement where viruses are proving useful tools to

Michael J. Adams; John F. Antoniw

246

Determinants of virulence of influenza A virus  

PubMed Central

Influenza A viruses cause yearly seasonal epidemics and occasional global pandemics in humans. In the last century, four human influenza A virus pandemics have occured. Ocasionally, influenza A viruses that circulate in other species, cross the species barrier and infect humans. Virus re-assortment (i.e. mixing of gene segments of multiple viruses) and the accumulation of mutations contribute to the emergence of new influenza A virus variants. Fortunately, most of these variants do not have the ability to spread among humans and subsequently cause a pandemic. In this review we focus on the threat of animal influenza A viruses which have shown the ability to infect humans. In addition, genetic factors which could alter the virulence of influenza A viruses are discussed. Identification and characterization of these factors may provide insights into genetic traits which change virulence and help us to understand which genetic determinants are of importance for the pandemic potential of animal influenza A viruses.

Schrauwen, Eefje J.A.; de Graaf, Miranda; Herfst, Sander; Rimmelzwaan, Guus F.; Osterhaus, Albert D.M.E.; Fouchier, Ron A.M.

2013-01-01

247

PC viruses: How do they do that  

SciTech Connect

The topic of PC Viruses has been an issue for a number of years now. They've been reported in every major newspaper, tabloids, television and radio. People from all fields get viruses: government, private sector businesses, home computers, schools, computer software suppliers. A definition is proposed to introduce the virus phenomenon. Virus authors come from a variety of communities. Motives and ideologies of authors are discussed, and examples of viruses are offered. Also mentioned is the growing number of viruses developed, isolated, and never distributed to the public at large, but kept within the antivirus research community. Virus examples are offered as well. Viruses are distributed not only through bulletin boards and shareware, but also from areas previously assumed to be safe, including the threat of receiving a virus through a standard in-house function, such as an in-house hardware maintenance shop. Three categories of viruses are presented: File Infecter viruses, Boot Sector Infecters, and the new category of Directory Entry Infecter virus. Also discussed are crossover viruses, that is, viruses which utilize a variety of techniques to ensure survival. An explanation of what is occurring within every stage of various viruses is given. Replication strategies common to all three types is noted, mainly the two different replication strategies of memory resident infecters and active selection infecters. A detailed definition, description and application of a stealth virus is presented. Detection strategies are discussed as each topic in this section is completed; a high level schemata of the operation of various virus detection programs ispresented. Since most eradication today is done using virus detection/eradication software, this paper attempts to reveal the techniques used by these packages.Included in the paper is the topic of manual eradication.

Pichnarczyk, K.

1992-07-01

248

PC viruses: How do they do that?  

SciTech Connect

The topic of PC Viruses has been an issue for a number of years now. They`ve been reported in every major newspaper, tabloids, television and radio. People from all fields get viruses: government, private sector businesses, home computers, schools, computer software suppliers. A definition is proposed to introduce the virus phenomenon. Virus authors come from a variety of communities. Motives and ideologies of authors are discussed, and examples of viruses are offered. Also mentioned is the growing number of viruses developed, isolated, and never distributed to the public at large, but kept within the antivirus research community. Virus examples are offered as well. Viruses are distributed not only through bulletin boards and shareware, but also from areas previously assumed to be safe, including the threat of receiving a virus through a standard in-house function, such as an in-house hardware maintenance shop. Three categories of viruses are presented: File Infecter viruses, Boot Sector Infecters, and the new category of Directory Entry Infecter virus. Also discussed are crossover viruses, that is, viruses which utilize a variety of techniques to ensure survival. An explanation of what is occurring within every stage of various viruses is given. Replication strategies common to all three types is noted, mainly the two different replication strategies of memory resident infecters and active selection infecters. A detailed definition, description and application of a stealth virus is presented. Detection strategies are discussed as each topic in this section is completed; a high level schemata of the operation of various virus detection programs ispresented. Since most eradication today is done using virus detection/eradication software, this paper attempts to reveal the techniques used by these packages.Included in the paper is the topic of manual eradication.

Pichnarczyk, K.

1992-07-01

249

Circulating avian influenza viruses closely related to the 1918 virus have pandemic potential.  

PubMed

Wild birds harbor a large gene pool of influenza A viruses that have the potential to cause influenza pandemics. Foreseeing and understanding this potential is important for effective surveillance. Our phylogenetic and geographic analyses revealed the global prevalence of avian influenza virus genes whose proteins differ only a few amino acids from the 1918 pandemic influenza virus, suggesting that 1918-like pandemic viruses may emerge in the future. To assess this risk, we generated and characterized a virus composed of avian influenza viral segments with high homology to the 1918 virus. This virus exhibited pathogenicity in mice and ferrets higher than that in an authentic avian influenza virus. Further, acquisition of seven amino acid substitutions in the viral polymerases and the hemagglutinin surface glycoprotein conferred respiratory droplet transmission to the 1918-like avian virus in ferrets, demonstrating that contemporary avian influenza viruses with 1918 virus-like proteins may have pandemic potential. PMID:24922572

Watanabe, Tokiko; Zhong, Gongxun; Russell, Colin A; Nakajima, Noriko; Hatta, Masato; Hanson, Anthony; McBride, Ryan; Burke, David F; Takahashi, Kenta; Fukuyama, Satoshi; Tomita, Yuriko; Maher, Eileen A; Watanabe, Shinji; Imai, Masaki; Neumann, Gabriele; Hasegawa, Hideki; Paulson, James C; Smith, Derek J; Kawaoka, Yoshihiro

2014-06-11

250

Foodborne viruses: an emerging problem.  

PubMed

Several groups of viruses may infect persons after ingestion and then are shed via stool. Of these, the norovirus (NoV) and hepatitis A virus (HAV) are currently recognised as the most important human foodborne pathogens with regard to the number of outbreaks and people affected in the Western world. NoV and HAV are highly infectious and may lead to widespread outbreaks. The clinical manifestation of NoV infection, however, is relatively mild. Asymptomatic infections are common and may contribute to the spread of the infection. Introduction of NoV in a community or population (a seeding event) may be followed by additional spread because of the highly infectious nature of NoV, resulting in a great number of secondary infections (50% of contacts). Hepatitis A is an increasing problem because of the decrease in immunity of populations in countries with high standards of hygiene. Molecular-based methods can detect viruses in shellfish but are not yet available for other foods. The applicability of the methods currently available for monitoring foods for viral contamination is unknown. No consistent correlation has been found between the presence of indicator microorganisms (i.e. bacteriophages, E. coli) and viruses. NoV and HAV are highly infectious and exhibit variable levels of resistance to heat and disinfection agents. However, they are both inactivated at 100 degrees C. No validated model virus or model system is available for studies of inactivation of NoV, although investigations could make use of structurally similar viruses (i.e. canine and feline caliciviruses). In the absence of a model virus or model system, food safety guidelines need to be based on studies that have been performed with the most resistant enteric RNA viruses (i.e. HAV, for which a model system does exist) and also with bacteriophages (for water). Most documented foodborne viral outbreaks can be traced to food that has been manually handled by an infected foodhandler, rather than to industrially processed foods. The viral contamination of food can occur anywhere in the process from farm to fork, but most foodborne viral infections can be traced back to infected persons who handle food that is not heated or otherwise treated afterwards. Therefore, emphasis should be on stringent personal hygiene during preparation. If viruses are present in food preprocessing, residual viral infectivity may be present after some industrial processes. Therefore, it is key that sufficient attention be given to good agriculture practice (GAP) and good manufacturing practice (GMP) to avoid introduction of viruses onto the raw material and into the food-manufacturing environment, and to HACCP to assure adequate management of (control over) viruses present during the manufacturing process. If viruses are present in foods after processing, they remain infectious in most circumstances and in most foods for several days or weeks, especially if kept cooled (at 4 degrees C). Therefore, emphasis should be on stringent personal hygiene during preparation. For the control of foodborne viral infections, it is necessary to: Heighten awareness about the presence and spread of these viruses by foodhandlers; Optimise and standardise methods for the detection of foodborne viruses; Develop laboratory-based surveillance to detect large, common-source outbreaks at an early stage; and Emphasise consideration of viruses in setting up food safety quality control and management systems (GHP, GMP, HACCP). PMID:14672828

Koopmans, Marion; Duizer, Erwin

2004-01-01

251

40 CFR 174.514 - Coat Protein of Watermelon Mosaic Virus-2 and Zucchini Yellow Mosaic Virus; exemption from the...  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Coat Protein of Watermelon Mosaic Virus-2 and Zucchini Yellow Mosaic Virus; exemption from the requirement for a tolerance...174.514 Coat Protein of Watermelon Mosaic Virus-2 and Zucchini Yellow Mosaic Virus;...

2013-07-01

252

Engineered resistance in potato against potato leafroll virus, potato virus A and potato virus Y.  

PubMed

Transgenic potato plants of Solanum tuberosum cultivar Vales Sovereign were generated that expressed fused, tandem, 200 bp segments derived from the capsid protein coding sequences of potato virus Y (PVY strain O) and potato leafroll virus (PLRV), as well as the cylindrical inclusion body coding sequences of potato virus A (PVA), as inverted repeat double-stranded RNAs, separated by an intron. The orientation of the expressed double-stranded RNAs was either sense-intron-antisense or antisense-intron-sense RNAs, and the double-stranded RNAs were processed into small RNAs. Four lines of such transgenic potato plants were assessed for resistance to infection by PVY-O, PLRV, or PVA, all transmitted by a natural vector, the green-peach aphid, Myzus persicae. Resistance was assessed by the absence of detectable virus accumulation in the foliage. All four transgenic potato lines tested showed 100% resistance to infection by either PVY-O or PVA, but variable resistance to infection by PLRV, ranging from 72 to 96% in different lines. This was regardless of the orientation of the viral inserts in the construct used to generate the transgenic plants and the gene copy number of the transgene. This demonstrates the potential for using tandem, fused viral segments and the inverted-repeat expression system to achieve multiple virus resistance to viruses transmitted by aphids in potato. PMID:23526159

Chung, Bong Nam; Yoon, Ju-Yeon; Palukaitis, Peter

2013-08-01

253

Immunological Memory after Exposure to Variola Virus, Monkeypox Virus, and Vaccinia Virus  

PubMed Central

We compared cellular and humoral immunity to vaccinia virus (VV) in individuals exposed to 3 different orthopoxviruses: 154 individuals previously vaccinated with VV, 7 individuals with a history of monkeypox virus infection, and 8 individuals with a history of variola virus infection. Among individuals vaccinated >20 years prior, 9 (14%) of 66 individuals demonstrated VV-specific interferon (IFN)-? enzyme-linked immunospot (ELISPOT) assay responses; 21 (50%) of 42 had lymphoproliferative (LP) responses, and 29 (97%) of 30 had VV-specific neutralizing antibodies. One year after monkeypox virus infection, 6 of 7 individuals had IFN-? ELISPOT responses, all had VV-specific LP responses, and 3 of 7 had VV-specific neutralizing antibodies. Of 8 individuals with a history of variola virus infection, 1 had a VV-specific IFN-? ELISPOT response, 4 had LP responses against whole VV, 7 had LP responses against heat-denatured vaccinia antigen, and 7 had VV-specific neutralizing antibodies. Survivors of variola virus infection demonstrated VV-specific CD4 memory cell responses and neutralizing antibodies >40 years after infection.

Sivapalasingam, Sumathi; Kennedy, Jeffrey S.; Borkowsky, William; Valentine, Fred; Zhan, Ming-Xia; Pazoles, Pamela; Paolino, Anna; Ennis, Francis A.; Steigbigel, Neal H.

2007-01-01

254

Comparison of cowpox-like viruses isolated from European zoos  

Microsoft Academic Search

Summary Poxviruses isolated from captive carnivores in Russia (Moscow virus) and elephants in Germany (elephant virus) were very closely-related to cowpox virus. Immunological analysis with absorbed sera separated elephant virus but not cowpox and Moscow virus, whereas polypeptide analysis separated cowpox but not elephant and Moscow virus. A combination of biological tests separated all three. The epidemiological implications are briefly

D. Baxby; W. B. Shackleton; Jean Wheeler; A. Turner

1979-01-01

255

Performance of Virus Resistant Transgenic Yellow Summer Squash in Alabama  

Microsoft Academic Search

Production of summer squash in Alabama and the southeastern United States is generally limited to spring and early summer due to the abundance of aphid transmitted viruses during the late summer and fall. Cucumber mosaic virus (CMV), Watermelon mosaic virus (WMV), Zucchini yellow mosaic virus (ZYMV), and Papaya ring spot virus (PRSV) are the most common viruses affecting Cucurbits in

Edward J. Sikora; John F. Murphy; Jason Burkett

2006-01-01

256

Viruses and viruslike particles of eukaryotic algae.  

PubMed Central

Until recently there was little interest or information on viruses and viruslike particles of eukaryotic algae. However, this situation is changing. In the past decade many large double-stranded DNA-containing viruses that infect two culturable, unicellular, eukaryotic green algae have been discovered. These viruses can be produced in large quantities, assayed by plaque formation, and analyzed by standard bacteriophage techniques. The viruses are structurally similar to animal iridoviruses, their genomes are similar to but larger (greater than 300 kbp) than that of poxviruses, and their infection process resembles that of bacteriophages. Some of the viruses have DNAs with low levels of methylated bases, whereas others have DNAs with high concentrations of 5-methylcytosine and N6-methyladenine. Virus-encoded DNA methyltransferases are associated with the methylation and are accompanied by virus-encoded DNA site-specific (restriction) endonucleases. Some of these enzymes have sequence specificities identical to those of known bacterial enzymes, and others have previously unrecognized specificities. A separate rod-shaped RNA-containing algal virus has structural and nucleotide sequence affinities to higher plant viruses. Quite recently, viruses have been associated with rapid changes in marine algal populations. In the next decade we envision the discovery of new algal viruses, clarification of their role in various ecosystems, discovery of commercially useful genes in these viruses, and exploitation of algal virus genetic elements in plant and algal biotechnology. Images

Van Etten, J L; Lane, L C; Meints, R H

1991-01-01

257

Adaptive Mutations in Sindbis Virus E2 and Ross River Virus E1 That Allow Efficient Budding of Chimeric Viruses  

Microsoft Academic Search

Alphavirus glycoproteins E2 and E1 form a heterodimer that is required for virus assembly. We have studied adaptive mutations in E2 of Sindbis virus (SIN) and E1 of Ross River virus (RR) that allow these two glycoproteins to interact more efficiently in a chimeric virus that has SIN E2 but RR E1. These mutations include K129E, K131E, and V237F in

KYONGMIN HWANG KIM; ELLEN G. STRAUSS; JAMES H. STRAUSS

2000-01-01

258

Siga adelante: la vida después del tratamiento del cáncer  

Cancer.gov

Consejos para supervivientes de cáncer con información sobre temas relacionados con la vida después del tratamiento, entre ellos, la atención médica de seguimiento, los cambios físicos y emocionales y los cambios en el estilo de vida.

259

Siga adelante: la vida después del tratamiento del cáncer  

Cancer.gov

E-book con consejos para supervivientes de cáncer e información sobre temas relacionados con la vida después del tratamiento, entre ellos, la atención médica de seguimiento, los cambios físicos y emocionales y los cambios en el estilo de vida.

260

Recovery of Virus Samples from Various Surfaces with the Integrated Virus Detection System.  

National Technical Information Service (NTIS)

Viruses are known to survive in environmental settings over various time periods. This study will show that certain viruses survive for a 24 h period, and certain viruses do not survive, depending on the substrate with which the viruses are in contact.

C. H. Wick P. E. McCubbin

2010-01-01

261

Avian-human reassortant influenza A viruses derived by mating avian and human influenza A viruses.  

PubMed

Reassortant influenza A viruses were produced by mating an avian virus (A/Mallard/NY/78, A/Mallard/Alberta/78, or A/Pintail/Alberta/79) with a wild-type human influenza A virus. From each mating a reassortant virus was obtained that contained the genes coding for the hemagglutinin and neuraminidase surface antigens of the human influenza A wild-type virus and the six other RNA segments ("internal genes") of the avian influenza A virus parent. The avian-human reassortant influenza viruses produced resembled their avian virus parent in that they produced plaques on MDCK monolayers at 42 C, a temperature restrictive for the human influenza viruses. In the trachea of squirrel monkeys, each avian-human reassortant influenza virus was as restricted in its replication as was its avian influenza virus parent. Thus, one or more of the six internal genes of each avian parent virus was responsible for restriction of the reassortant virus in monkeys. The A/Washington/80 X A/Mallard/NY/78 reassortant virus retained its phenotype of restricted replication in monkeys after five serial passages in vivo. It also failed to transmit to cagemates or induce resistance to wild-type virus challenge, and it did not initiate a systemic or enteric infection. These findings form the basis for evaluation of these attenuated avian-human reassortant influenza A viruses as live attenuated vaccines for humans. PMID:6501928

Murphy, B R; Buckler-White, A J; London, W T; Harper, J; Tierney, E L; Miller, N T; Reck, L J; Chanock, R M; Hinshaw, V S

1984-12-01

262

Genetic Diversity in RNA Virus Quasispecies Is Controlled by Host-Virus Interactions  

Microsoft Academic Search

Many RNA viruses have genetically diverse populations known as quasispecies. Important biological char- acteristics may be related to the levels of diversity in the quasispecies (quasispecies cloud size), including adaptability and host range. Previous work using Tobacco mosaic virus and Cucumber mosaic virus indicated that evolutionarily related viruses have very different levels of diversity in a common host. The quasispecies

WILLIAM L. SCHNEIDER; MARILYN J. ROOSSINCK

2001-01-01

263

Mouse Neuroinvasive Phenotype of West Nile Virus Strains Varies Depending upon Virus Genotype  

Microsoft Academic Search

Despite recent advances in the genetics of West Nile (WN) virus, relatively little is known about the molecular basis of virulence of this virus. In particular, although the genotype of the WN virus strain that was recently introduced into North America has been determined, there have been few experimental studies on the virulence phenotype of the virus. We compared genetic

David W. C. Beasley; Li Li; Miguel T. Suderman; Alan D. T. Barrett

2002-01-01

264

Coping with Computer Viruses: General Discussion and Review of Symantec Anti-Virus for the Macintosh.  

ERIC Educational Resources Information Center

Discusses computer viruses that attack the Macintosh and describes Symantec AntiVirus for Macintosh (SAM), a commercial program designed to detect and eliminate viruses; sample screen displays are included. SAM is recommended for use in library settings as well as two public domain virus protection programs. (four references) (MES)

Primich, Tracy

1992-01-01

265

Dengue viruses - an overview  

PubMed Central

Dengue viruses (DENVs) cause the most common arthropod-borne viral disease in man with 50–100 million infections per year. Because of the lack of a vaccine and antiviral drugs, the sole measure of control is limiting the Aedes mosquito vectors. DENV infection can be asymptomatic or a self-limited, acute febrile disease ranging in severity. The classical form of dengue fever (DF) is characterized by high fever, headache, stomach ache, rash, myalgia, and arthralgia. Severe dengue, dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS) are accompanied by thrombocytopenia, vascular leakage, and hypotension. DSS, which can be fatal, is characterized by systemic shock. Despite intensive research, the underlying mechanisms causing severe dengue is still not well understood partly due to the lack of appropriate animal models of infection and disease. However, even though it is clear that both viral and host factors play important roles in the course of infection, a fundamental knowledge gap still remains to be filled regarding host cell tropism, crucial host immune response mechanisms, and viral markers for virulence.

Back, Anne Tuiskunen; Lundkvist, Ake

2013-01-01

266

Hepatitis B virus morphogenesis  

PubMed Central

The hepatitis B virus (HBV) particle consists of an envelope containing three related surface proteins and probably lipid and an icosahedral nucleocapsid of approximately 30 nm diameter enclosing the viral DNA genome and DNA polymerase. The capsid is formed in the cytosol of the infected cell during packaging of an RNA pregenome replication complex by multiple copies of a 21-kDa C protein. The capsid gains the ability to bud during synthesis of the viral DNA genome by reverse transcription of the pregenome in the lumen of the particle. The three envelope proteins S, M, and L shape a complex transmembrane fold at the endoplasmic reticulum, and form disulfide-linked homo- and heterodimers. The transmembrane topology of a fraction of the large envelope protein L changes post-translationally, therefore, the N terminal domain of L (preS) finally appears on both sides of the membrane. During budding at an intracellular membrane, a short linear domain in the cytosolic preS region interacts with binding sites on the capsid surface. The virions are subsequently secreted into the blood. In addition, the surface proteins can bud in the absence of capsids and form subviral lipoprotein particles of 20 nm diameter which are also secreted.

Bruss, Volker

2007-01-01

267

Hepatitis B virus replication  

PubMed Central

Hepadnaviruses, including human hepatitis B virus (HBV), replicate through reverse transcription of an RNA intermediate, the pregenomic RNA (pgRNA). Despite this kinship to retroviruses, there are fundamental differences beyond the fact that hepadnavirions contain DNA instead of RNA. Most peculiar is the initiation of reverse transcription: it occurs by protein-priming, is strictly committed to using an RNA hairpin on the pgRNA, ?, as template, and depends on cellular chaperones; moreover, proper replication can apparently occur only in the specialized environment of intact nucleocapsids. This complexity has hampered an in-depth mechanistic understanding. The recent successful reconstitution in the test tube of active replication initiation complexes from purified components, for duck HBV (DHBV), now allows for the analysis of the biochemistry of hepadnaviral replication at the molecular level. Here we review the current state of knowledge at all steps of the hepadnaviral genome replication cycle, with emphasis on new insights that turned up by the use of such cell-free systems. At this time, they can, unfortunately, not be complemented by three-dimensional structural information on the involved components. However, at least for the ? RNA element such information is emerging, raising expectations that combining biophysics with biochemistry and genetics will soon provide a powerful integrated approach for solving the many outstanding questions. The ultimate, though most challenging goal, will be to visualize the hepadnaviral reverse transcriptase in the act of synthesizing DNA, which will also have strong implications for drug development.

Beck, Juergen; Nassal, Michael

2007-01-01

268

Influenza A Virus Proteins NS1 and Hemagglutinin Along with M2 Are Involved in Stimulation of Autophagy in Infected Cells  

PubMed Central

The NS1 protein of influenza A virus is known to downregulate apoptosis early in infection in order to support virus replication (O. P. Zhirnov, T. E. Konakova, T. Wolff, and H. D. Klenk, J. Virol. 76:1617–1625, 2002). In the present study, we analyzed the development of autophagy, another mechanism to protect cells from degradation that depends on NS1 expression. To this end, we compared autophagy in cells infected with wild-type (WT) influenza virus and virus lacking the NS1 gene (delNS1 virus). The results show that in WT-infected cells but not in delNS1 virus-infected cells, synthesis of the autophagy marker LC3-II, the lipidated form of microtubule light chain-associated protein LC3, is stimulated and that LC3-II accumulates in a perinuclear zone enriched with double-layered membrane vesicles characteristic of autophagosomes. Transfection experiments revealed that NS1 expressed alone was unable to upregulate autophagy, whereas hemagglutinin (HA) and M2 were. Proteolytic cleavage of HA increased autophagy. Taken together, these observations indicate that NS1 stimulates autophagy indirectly by upregulating the synthesis of HA and M2. Thus, it appears that NS1, besides downregulating apoptosis, is involved in upregulation of autophagy and that it supports the survival of infected cells by both mechanisms.

Klenk, H. D.

2013-01-01

269

Induction of protective immunity in swine by recombinant bamboo mosaic virus expressing foot-and-mouth disease virus epitopes  

Microsoft Academic Search

BACKGROUND: Plant viruses can be employed as versatile vectors for the production of vaccines by expressing immunogenic epitopes on the surface of chimeric viral particles. Although several viruses, including tobacco mosaic virus, potato virus X and cowpea mosaic virus, have been developed as vectors, we aimed to develop a new viral vaccine delivery system, a bamboo mosaic virus (BaMV), that

Chung-Da Yang; Jia-Teh Liao; Chen-Yen Lai; Ming-Hwa Jong; Chi-Ming Liang; Yeou-Liang Lin; Na-Sheng Lin; Yau-Heiu Hsu; Shu-Mei Liang

2007-01-01

270

Boletín del Instituto Nacional del Cáncer - 05-25-2010  

Cancer.gov

Aproximadamente 41.000 participantes en un estudio en el Reino Unido se sometieron una sola vez a una examen de detección en la parte inferior del colon mediante el uso de un sigmoidoscopio, un instrumento delgado en forma de tubo que se inserta a través del recto para buscar lesiones precancerosas o cancerosas. Este dispositivo también tiene una herramienta para extraer pólipos potencialmente precancerosos.

271

Autophagic machinery activated by dengue virus enhances virus replication  

SciTech Connect

Autophagy is a cellular response against stresses which include the infection of viruses and bacteria. We unravel that Dengue virus-2 (DV2) can trigger autophagic process in various infected cell lines demonstrated by GFP-LC3 dot formation and increased LC3-II formation. Autophagosome formation was also observed under the transmission electron microscope. DV2-induced autophagy further enhances the titers of extracellular and intracellular viruses indicating that autophagy can promote viral replication in the infected cells. Moreover, our data show that ATG5 protein is required to execute DV2-induced autophagy. All together, we are the first to demonstrate that DV can activate autophagic machinery that is favorable for viral replication.

Lee, Y.-R. [Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan (China); Lei, H.-Y. [Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan (China); Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan (China); Liu, M.-T. [Tainan Hospital, Department of Health, Executive Yuan, Tainan, Taiwan (China); Wang, J.-R. [Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan, Taiwan (China); Chen, S.-H. [Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan (China); Jiang-Shieh, Y.-F. [Department of Cell Biology and Anatomy, College of Medicine, National Cheng Kung University, Tainan, Taiwan (China); Lin, Y.-S. [Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan (China); Yeh, T.-M. [Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan, Taiwan (China); Liu, C.-C. [Department of Pediatrics, College of Medicine, National Cheng Kung University, Tainan, Taiwan (China); Liu, H.-S. [Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan (China)], E-mail: a713@mail.ncku.edu.tw

2008-05-10

272

West Nile Virus in the Workplace  

MedlinePLUS

... 2003]. West Nile Virus Infection Among Turkey Breeder Farm Workers --- Wisconsin, 2002. MMWR 52(42): 1017-1019. ... and Health Topics Industries & Occupations Hazards & Exposures Diseases & Injuries West Nile Virus Questions and Answers Safety & Prevention ...

273

Towards a Vaccine Against Ebola Virus.  

National Technical Information Service (NTIS)

Ebola virus infection causes hemorrhagic fever with high mortality rates in humans and nonhuman primates. Currently, there are no vaccines or therapies approved for human use. Outbreaks of Ebola virus have been infrequent, largely confined to remote locat...

T. W. Geisbert P. B. Jahrling

2003-01-01

274

Cultivation of Hepatitis Virus in Tissue Culture.  

National Technical Information Service (NTIS)

A major step in the cultivation of hepatitis virus and the eventual development of a viral vaccine revolves about the development of appropriate substrates. Hepatitis virus is known to grow rapidly and successfully in liver in vivo. If appropriate tissue ...

G. L. Gitnick

1973-01-01

275

Pathogenesis of Sendai Virus Infection in Mice.  

National Technical Information Service (NTIS)

Mice experimentally exposed to Sendai virus (Myxovirus parainfluenza type I) by aerosol developed virus titers in both nasal washings and lungs that peaked at 5 or 6 days after exposure and disappeared by 12 days after exposure. Hemagglutination-inhibitio...

J. M. Reddecliff L. H. Appell P. J. Gerone R. M. Kovatch

1970-01-01

276

Heat Shock Response and Virus Replication.  

National Technical Information Service (NTIS)

The present invention discloses a method of inhibiting heat shock protein-dependent virus replication in cells and in animals. The present invention also discloses a method of identifying compounds which inhibit heat shock protein-dependent virus replicat...

P. Moseley M. Cotten B. Hjelle A. Panganiban P. C. Angeletti

2005-01-01

277

Host Parasite Relationships of Chimpanzee Viruses.  

National Technical Information Service (NTIS)

Throat and fecal specimens collected in four sampling from chimpanzees resulted in recovery of 79 viruses from 53 of 187 chimpanzees. Fecal specimens collected from chimpanzees recently imported from Africa resulted in recovery of one or more viruses from...

F. Coulston K. F. Soike

1969-01-01

278

Disappearance of Chikungunya Virus from Bangkok.  

National Technical Information Service (NTIS)

Although infections with Chikungunya virus were common in Bangkok during the 1960's and early 1970's, disease surveillance during the period 1979-1982 indicated that infections with this virus had virtually ceased.

D. S. Burke A. Nisalak S. Nimmannitya

1985-01-01

279

Se da a conocer el plan del Instituto Nacional del Cáncer para acelerar la investigación del cáncer  

Cancer.gov

En la 100va Reunión Anual de la Asociación Estadounidense de Investigación del Cáncer realizada en Denver, el director del Instituto Nacional del Cáncer, doctor John E. Niederhuber, dio a conocer detalles importantes, tales como financiamiento de más subvenciones, creación de una plataforma para atención personalizada del cáncer y un programa acelerado de genética del cáncer que hará avanzar la investigación oncológica en este nuevo ambiente económico.

280

MODELADO Y SIMULACION DEL SISTEMA CARDIOVASCULAR FETAL  

Microsoft Academic Search

Resumen: En el modelado fisiológico, el propósito es comprender las funciones del cuerpo humano. Con este propósito, se abordan problemas del embarazo y el parto para minimizar las cesáreas innecesarias en mujeres propensas a cursar con Sufrimiento Fetal Agudo (SFA). En el presente estudio se realizó: el Modelado Matemático del Sistema Cardiovascular Fetal (SCVF), la Simulación y Validación del SCVF.

Rubén Moreno

281

Electrical detection of single viruses  

PubMed Central

We report direct, real-time electrical detection of single virus particles with high selectivity by using nanowire field effect transistors. Measurements made with nanowire arrays modified with antibodies for influenza A showed discrete conductance changes characteristic of binding and unbinding in the presence of influenza A but not paramyxovirus or adenovirus. Simultaneous electrical and optical measurements using fluorescently labeled influenza A were used to demonstrate conclusively that the conductance changes correspond to binding/unbinding of single viruses at the surface of nanowire devices. pH-dependent studies further show that the detection mechanism is caused by a field effect, and that the nanowire devices can be used to determine rapidly isoelectric points and variations in receptor-virus binding kinetics for different conditions. Lastly, studies of nanowire devices modified with antibodies specific for either influenza or adenovirus show that multiple viruses can be selectively detected in parallel. The possibility of large-scale integration of these nanowire devices suggests potential for simultaneous detection of a large number of distinct viral threats at the single virus level.

Patolsky, Fernando; Zheng, Gengfeng; Hayden, Oliver; Lakadamyali, Melike; Zhuang, Xiaowei; Lieber, Charles M.

2004-01-01

282

Droplet Microfluidics for Virus Discovery  

NASA Astrophysics Data System (ADS)

The ability to detect, isolate, and characterize an infectious agent is important for diagnosing and curing infectious diseases. Detecting new viral diseases is a challenge because the number of virus particles is often low and/or localized to a small subset of cells. Even if a new virus is detected, it is difficult to isolate it from clinical or environmental samples where multiple viruses are present each with very different properties. Isolation is crucial for whole genome sequencing because reconstructing a genome from fragments of many different genomes is practically impossible. We present a Droplet Microfluidics platform that can detect, isolate and sequence single viral genomes from complex samples containing mixtures of many viruses. We use metagenomic information about the sample of mixed viruses to select a short genomic sequence whose genome we are interested in characterizing. We then encapsulate single virions from the same sample in picoliter volume droplets and screen for successful PCR amplification of the sequence of interest. The selected drops are pooled and their contents sequenced to reconstruct the genome of interest. This method provides a general tool for detecting, isolating and sequencing genetic elements in clinical and environmental samples.

Rotem, Assaf; Cockrell, Shelley; Guo, Mira; Pipas, James; Weitz, David

2012-02-01

283

Viruses and thyroiditis: an update  

PubMed Central

Viral infections are frequently cited as a major environmental factor involved in subacute thyroiditis and autoimmune thyroid diseases This review examines the data related to the role of viruses in the development of thyroiditis. Our research has been focused on human data. We have reviewed virological data for each type of thyroiditis at different levels of evidence; epidemiological data, serological data or research on circulating viruses, direct evidence of thyroid tissue infection. Interpretation of epidemiological and serological data must be cautious as they don't prove that this pathogen is responsible for the disease. However, direct evidence of the presence of viruses or their components in the organ are available for retroviruses (HFV) and mumps in subacute thyroiditis, for retroviruses (HTLV-1, HFV, HIV and SV40) in Graves's disease and for HTLV-1, enterovirus, rubella, mumps virus, HSV, EBV and parvovirus in Hashimoto's thyroiditis. However, it remains to determine whether they are responsible for thyroid diseases or whether they are just innocent bystanders. Further studies are needed to clarify the relationship between viruses and thyroid diseases, in order to develop new strategies for prevention and/or treatment.

Desailloud, Rachel; Hober, Didier

2009-01-01

284

Fate of Sendai Virus Ribonucleoprotein in Virus-infected Cells  

PubMed Central

The cytoplasmic extracts of Ehrlich ascites tumor cells infected with 32PO4 and 3H-leucine-labeled Sendai virus have been examined during the course of infection with respect to sedimentation behavior and buoyant densities of input virus radioactivity. It was found that 32P and 3H radioactivities were coincident, and, at 30 min after infection, the bulk of radioactivity was recovered in the polysome region of a sucrose gradient in the position of Sendai virus ribonucleoprotein (210S). The heterogeneity of radioactivity profiles appeared at 1 hr after infection and increased during 6 hr of incubation. The buoyant densities of input virus components were determined by banding in CsCl gradient. Here again the bulk of coincident 32P and 3H radioactivity at 30 min after infection banded at the same density as Sendai virus ribonucleoprotein (1.31 g/cm3.) This component disappeared at 3 hr after infection, and 32P and 3H radioactivities were now found in components banded at densities 1.38, 1.41, 1.45, 1.49, and 1.55 g/cm3. The results presented are consistent with the idea that virus ribonucleoprotein is retained in the cytoplasm of infected cells during at least 6 hr of incubation, being partly deproteinized in the course of infection. The nature of components which banded at ? = 1.41, 1.45, 1.49, and 1.55 as complexes of partly deproteinized ribonucleoprotein with ribosomes will be described in a separate paper.

Bukrinskaya, A. G.; Zhdanov, V. M.; Vorkunova, G. K.

1969-01-01

285

Herpes simplex virus growth, preparation, and assay.  

PubMed

In order to study the biology of herpes simplex virus or to use it as a vector in gene therapy, it is necessary to grow the virus and to prepare virus stocks. Many different protocols are available from different research groups working with herpes simplex virus type 1 or 2 (HSV-1 or HSV-2). This chapter describes the procedures used in our laboratory. PMID:24671674

Marconi, Peggy; Manservigi, Roberto

2014-01-01

286

Recent advances in oncolytic virus design  

Microsoft Academic Search

The cytolytic properties of viruses can be used to treat cancer. Replication of certain viruses is favoured in cancer cells,\\u000a whereas others can be modified to obtain tumour specificity. This approach has evolved to become a new discipline called virotherapy.\\u000a In addition, these replication-competent (oncolytic) viruses can be adapted as vectors for cancer gene therapy. The “armed”\\u000a viruses show a

Rubén Hernández-Alcoceba

2011-01-01

287

Virus meningo-encephalitis in Slovenia  

PubMed Central

An organism was isolated from the blood of a patient clinically diagnosed as suffering from virus meningo-encephalitis; the organism causes illness and death in white mice. The antigen prepared from the brains of mice infected with this organism fixes complement with sera from typical cases of virus meningo-encephalitis. From its biological and serological characteristics, the isolated organism appears to belong to the group of neurotropic viruses and to be the causative agent of virus meningo-encephalitis in Slovenia.

Vesenjak-Zmijanac, J.; Bedjanic, M.; Rus, S.; Kmet, J.

1955-01-01

288

Epidemiology of influenza virus in Korean poultry  

Microsoft Academic Search

Epidemiological information on currently circulating influenza viruses in poultry in Korea has not been available. We performed the surveillance of avian influenza viruses in the live poultry markets where chickens, ducks, geese, and doves are sold. H9N2, H3N2, and H6N1 influenza viruses were isolated from poultry in the Korean live bird markets. H9N2 influenza viruses were mainly isolated from chickens;

Sang Heui Seo; Hyun Soo Kim

2004-01-01

289

Characteristics of Filoviridae: Marburg and Ebola Viruses  

NASA Astrophysics Data System (ADS)

Filoviruses are enveloped, nonsegmented negative-stranded RNA viruses. The two species, Marburg and Ebola virus, are serologically, biochemically, and genetically distinct. Marburg virus was first isolated during an outbreak in Europe in 1967, and Ebola virus emerged in 1976 as the causative agent of two simultaneous outbreaks in southern Sudan and northern Zaire. Although the main route of infection is known to be person-to-person transmission by intimate contact, the natural reservoir for filoviruses still remains a mystery.

Beer, Brigitte; Kurth, Reinhard; Bukreyev, Alexander

290

Neutralizing antibodies to different proteins of African swine fever virus inhibit both virus attachment and internalization.  

PubMed Central

African swine fever virus induces in convalescent pigs antibodies that neutralized the virus before and after binding to susceptible cells, inhibiting both virus attachment and internalization. A further analysis of the neutralization mechanisms mediated by the different viral proteins showed that antibodies to proteins p72 and p54 are involved in the inhibition of a first step of the replication cycle related to virus attachment, while antibodies to protein p30 are implicated in the inhibition of virus internalization.

Gomez-Puertas, P; Rodriguez, F; Oviedo, J M; Ramiro-Ibanez, F; Ruiz-Gonzalvo, F; Alonso, C; Escribano, J M

1996-01-01

291

Antioxidantes y prevención del cáncer  

Cancer.gov

Hoja informativa acerca de los antioxidantes, sustancias que pueden proteger las células del daño causado por moléculas inestables conocidas como radicales libres. El daño de los radicales libres puede resultar en cáncer.

292

Case Study: del Amo Bioventing  

EPA Science Inventory

The attached presentation discusses the fundamentals of bioventing in the vadose zone. The basics of bioventing are presented. The experience to date with the del Amo Superfund Site is presented as a case study....

293

ULTRAFILTRATION OF THE VIRUS OF POLIOMYELITIS  

PubMed Central

From the ultrafiltration analysis the size of the virus of human poliomyelitis has been estimated to be somewhere between 12 and 17 mµ. Technical difficulties encountered and the low concentration of the virus make it seem possible that the virus is even smaller.

Theiler, Max; Bauer, Johannes H.

1934-01-01

294

MODEL OF VIRUS TRANSPORT IN UNSATURATED SOIL  

EPA Science Inventory

As a result of the recently-proposed mandatory ground-water disinfection requirements to inactivate viruses in potable water supplies, there has been increasing interest in virus fate and transport in the subsurface. everal models have been developed to predict the fate of viruse...

295

Replication-selective viruses for cancer therapy  

Microsoft Academic Search

Advances in our understanding of the molecular basis of cancer and the availability of technology to genetically engineer viruses have led to the development of replication-competent viruses to treat cancer. In theory, replication-selective viruses offer several appealing properties as biological agents for cancer therapy: they kill tumor cells selectively, and their replication leads to amplification of their oncolytic potential. Most

Carola Biederer; Stefan Ries; Christian H. Brandts; Frank McCormick

2002-01-01

296

Hot crenarchaeal viruses reveal deep evolutionary connections  

Microsoft Academic Search

The discovery of archaeal viruses provides insights into the fundamental biochemistry and evolution of the Archaea. Recent studies have identified a wide diversity of archaeal viruses within the hot springs of Yellowstone National Park and other high-temperature environments worldwide. These viruses are often morphologically unique and code for genes with little similarity to other known genes in the biosphere, a

Alice C. Ortmann; Blake Wiedenheft; Trevor Douglas; Mark Young

2006-01-01

297

Email Virus Propagation Modeling and Analysis  

Microsoft Academic Search

Email viruses constitute one of the major Internet security problems. In this paper we present an email virus model that accounts for the behaviors of email users, such as email checking frequency and the probability of opening an email attachment. Email viruses spread over a logical network defined by email address books. The topology of email network plays an important

Cliff C. Zou; Don Towsley; Weibo Gong

2003-01-01

298

Human Immunodeficiency Virus (HIV) Primary Infection  

MedlinePLUS

newsletter | contact Share | Human Immunodeficiency Virus (HIV) Primary Infection Information for adults A A A When HIV is first contracted, there may be ... 1–6 weeks following exposure to HIV (the human immunodeficiency virus). Chronic infection with this virus can ...

299

Interferon-Inducing Characteristics of Mm Virus.  

National Technical Information Service (NTIS)

Interferon induction by MM virus in mice and in L cells was studied. In mice the virus readily induced interferon. The time of appearance was dose-dependent. A large virus dose induced interferon by 4 hr, whereas a small dose resulted in interferon produc...

D. J. Giron F. F. Pindak J. P. Schmidt P. T. Allen

1970-01-01

300

Current best practice against computer viruses  

Microsoft Academic Search

Summarizes research on viruses and defenses. The author examines the state-of-the-art in virus defense today and describes how normal computing activities can proceed without undue risk of substantial viral harm. He then describes a set of redundant integrity protection mechanisms used in defending against computer viruses in untrusted computing environments. They include applications of coding theory, cryptography, operating system modifications,

Fred Cohen

1991-01-01

301

Open Problems in Computer Virus Research  

Microsoft Academic Search

Over a decade of work on the computer virus problem has resulted in a number of useful scientific and technological achievements. The study of biological epidemiology has been extended to help us understand when and why computer viruses spread. Techniques have been developed to help us estimate the safety and effectiveness of anti-virus technology before it is deployed. Technology for

Steve R. White

1998-01-01

302

Immunity to avian influenza A viruses  

Microsoft Academic Search

Summary While the basic principles of immunity to the influenza A viruses are probably similar for all vertebrates, detailed understanding is based largely on experiments in laboratory mice. Elements of the innate response limit early virus replication, although high pathogenicity strains can trigger effusive cytokine\\/chemokine production and lethal shock. Virus clearance is normally mediated via CD8+ effector T cells but,

P. C. Doherty; L. E. Brown; A. Kelso; P. G. Thomas

2009-01-01

303

The greasy response to virus infections  

PubMed Central

Previews Virus replication requires lipid metabolism, but how lipids mediate virus infection remains obscure. In this issue, Amini-Bavil-Olyaee et al. (2013) reveal that IFITM proteins disturb cholesterol homeostasis to block virus entry. Previously in Cell, Morita and colleagues (2013) showed the antiviral potency of the lipid mediator protectin D1.

Tanner, Lukas Bahati; Lee, Benhur

2013-01-01

304

Human influenza virus recognition of sialyloligosaccharides  

Microsoft Academic Search

Sialic acids are essential components of cell-surface receptors utilized by influenza viruses. To evaluate the recognition of asialic sugar parts of the receptor, three representative strains of human influenza A and B viruses were tested for their binding of a panel of sialyloligosaccharides. The highest affinity binding carbohydrate determinants recognized by the viruses in a context of different core structures

A. S. Gambaryan; V. E. Piskarev; I. A. Yamskov; A. M. Sakharov; A. B. Tuzikov; N. V. Bovin; N. E. Nifant'ev; M. N. Matrosovich

1995-01-01

305

Photoinactivation of Vaccinia Virus with Rose Bengal  

Microsoft Academic Search

SUMMARY Photoinactivation of vaccinia virus was complete but slower with rose bengal than with methylene blue as the sensitizing dye. Photoinactivation was inhibited and changes in dye absorption spectra occurred when protein but not when nucleic acid was added to rose bengal + virus mixtures, with methylene blue+virus mixtures nucleic aid but not protein was inhibitory. Photo- inactivation with methylene

G. S. Turner; C. Kaplan

1968-01-01

306

Virus entry: molecular mechanisms and biomedical applications  

Microsoft Academic Search

Viruses have evolved to enter cells from all three domains of life — Bacteria, Archaea and Eukaryotes. Of more than 3,600 known viruses, hundreds can infect human cells and most of those are associated with disease. To gain access to the cell interior, animal viruses attach to host-cell receptors. Advances in our understanding of how viral entry proteins interact with

Dimiter S. Dimitrov

2004-01-01

307

Computer virus information update CIAC-2301.  

National Technical Information Service (NTIS)

While CIAC periodically issues bulletins about specific computer viruses, these bulletins do not cover all the computer viruses that affect desktop computers. The purpose of this document is to identify most of the known viruses for the MS-DOS and Macinto...

W. J. Orvis

1994-01-01

308

Testing thermal resistance of viruses.  

PubMed

Representative viral strains recommended for virucidal testing of biocides in human medicine were used for testing viral resistance to dry heat using the new Keredusy hot instrument. The results demonstrate that poliovirus type 1 could be inactivated by treatment at 75 degrees C for 1 h. For inactivation of adenovirus type 5, 2 h at 85 degrees C was needed. The infectivity of polyomavirus SV40 could only be influenced significantly by a temperature of 95 degrees C over a period of 1 h, whereas vaccinia virus and bovine viral diarrhea virus needed a time interval of 2 h at 95 degrees C. The infectivity of bovine parvovirus could not be influenced significantly by exposure to 95 degrees C for 2 h. In conclusion, human viruses and their surrogates for testing biocides may have a considerable thermal resistance that makes them difficult to be inactivated only by dry heat. PMID:19039515

Sauerbrei, Andreas; Wutzler, P

2009-01-01

309

Searching for virus phylotypes  

PubMed Central

Motivation: Large phylogenies are being built today to study virus evolution, trace the origin of epidemics, establish the mode of transmission and survey the appearance of drug resistance. However, no tool is available to quickly inspect these phylogenies and combine them with extrinsic traits (e.g. geographic location, risk group, presence of a given resistance mutation), seeking to extract strain groups of specific interest or requiring surveillance. Results: We propose a new method for obtaining such groups, which we call phylotypes, from a phylogeny having taxa (strains) annotated with extrinsic traits. Phylotypes are subsets of taxa with close phylogenetic relationships and common trait values. The method combines ancestral trait reconstruction using parsimony, with combinatorial and numerical criteria measuring tree shape characteristics and the diversity and separation of the potential phylotypes. A shuffling procedure is used to assess the statistical significance of phylotypes. All algorithms have linear time complexity. This results in low computing times, typically a few minutes for the larger data sets with a number of shuffling steps. Two HIV-1 data sets are analyzed, one of which is large, containing >3000 strains of HIV-1 subtype C collected worldwide, where the method shows its ability to recover known clusters and transmission routes, and to detect new ones. Availability: This method and companion tools are implemented in an interactive Web interface (www.phylotype.org), which provides a wide choice of graphical views and output formats, and allows for exploratory analyses of large data sets. Contact: francois.chevenet@ird.fr, gascuel@lirmm.fr Supplementary information: Supplementary data are available at Bioinformatics online.

Chevenet, Francois; Jung, Matthieu; Peeters, Martine; de Oliveira, Tulio; Gascuel, Olivier

2013-01-01

310

Lagos Bat Virus in Kenya?  

PubMed Central

During lyssavirus surveillance, 1,221 bats of at least 30 species were collected from 25 locations in Kenya. One isolate of Lagos bat virus (LBV) was obtained from a dead Eidolon helvum fruit bat. The virus was most similar phylogenetically to LBV isolates from Senegal (1985) and from France (imported from Togo or Egypt; 1999), sharing with these viruses 100% nucleoprotein identity and 99.8 to 100% glycoprotein identity. This genome conservancy across space and time suggests that LBV is well adapted to its natural host species and that populations of reservoir hosts in eastern and western Africa have sufficient interactions to share pathogens. High virus concentrations, in addition to being detected in the brain, were detected in the salivary glands and tongue and in an oral swab, suggesting that LBV is transmitted in the saliva. In other extraneural organs, the virus was generally associated with innervations and ganglia. The presence of infectious virus in the reproductive tract and in a vaginal swab implies an alternative opportunity for transmission. The isolate was pathogenic for laboratory mice by the intracerebral and intramuscular routes. Serologic screening demonstrated the presence of LBV-neutralizing antibodies in E. helvum and Rousettus aegyptiacus fruit bats. In different colonies the seroprevalence ranged from 40 to 67% and 29 to 46% for E. helvum and R. aegyptiacus, respectively. Nested reverse transcription-PCR did not reveal the presence of viral RNA in oral swabs of bats in the absence of brain infection. Several large bat roosts were identified in areas of dense human populations, raising public health concerns for the potential of lyssavirus infection.

Kuzmin, Ivan V.; Niezgoda, Michael; Franka, Richard; Agwanda, Bernard; Markotter, Wanda; Beagley, Janet C.; Urazova, Olga Y.; Breiman, Robert F.; Rupprecht, Charles E.

2008-01-01

311

Alberto del Pozo  

NSDL National Science Digital Library

The Cuban Heritage Collection of the University of Miami Libraries was a recipient of 17 original illustrations by Alberto del Pozo in 1998 from the Campilli family. "The Oricha Collection" is their gift, and it contains illustrations in pen, crayon, and ink and the collection "pays homage to the primary gods and goddesses that comprise the Afro-Cuban religion of Santer'a." The "Introduction" near the top of the page, is a good place for visitors to start learning about Pozo, who was a Parson's School of Design-trained, Cuban artist who died at the age of 47. The "Biographical Sketch" is worth looking at as well. Examples of his colorful, heavily patterned and symbolism-intensive drawings of Santeria gods and goddesses can be found in the link "Gallery". The description of each drawing is given in English and Spanish. Finally, visitors interested in more information on the Santeria, can look at the "Further Readings" link for authoritative books on the subject.

312

[Bovine diarrhea virus: an update].  

PubMed

Bovine Viral Diarrhea Virus (BVDV) is a pathogen of cattle, member of the family Flaviviridae, genus pestivirus, which also includes Classical Swine Fever Virus (CSFV, or hog cholera virus), and Border Disease Virus of sheep (BDV). It causes important economical losses associated mainly with reproductive failure. Pestiviruses are small enveloped viruses, with a diameter of about 40 nm. The nucleocapsid is probably icosahedral . The genome consists of a single stranded positive RNA, encoding approximately 430 kD of proteic product. Genetic expression consists of the synthesis of a polyprotein which is co- and post-translationally processed. According to its behavior "in vitro" two biotypes can be distinguished: non cytopathic (ncp) and cytopathic (cp), most probably derived from the ncp through mutations and/or recombination. BVDV is able to cross the placenta and infect the fetus, causing a variety of problems, from fetal death to the birth of a persistently infected (P) calf, according to the fetal age at the time of infection. PI animals are immunotolerant to the virus and shed it in all secretions. Only the ncp biotype has been isolated from PI animals. The superinfection of a PI animal with a cp strain causes mucosal disease, always fatal. Outbreaks of a severe, sometimes hemorrhagic disease, caused by ncp BVDV, have occurred in Canada and USA since 1993. Genomic and serological differences between the "traditional" strains and the viruses isolated from these outbreaks led to the division of BVDV in subtypes I and II, both including cp and ncp strains. Analyses of the non coding 5'-UTR zone of the genome of pestiviruses from different species (bovine, ovine, porcine) suggest that there are at least 3 genotypes within the genus. A new classification of these viruses, based on genomic sequence instead of species of origin, has been proposed. Genomic heterogeneity exists in the BVDV genome, which presents 3 hypervariable zones, 2 of them in the major neutralizing protein. In Argentina prevalence of BVDV antibodies in cattle population is 70%, and the prevalence of persistent infections is around 1%. PMID:9229725

Kobrak, A; Weber, E L

1997-01-01

313

Dominant resistance against plant viruses  

PubMed Central

To establish a successful infection plant viruses have to overcome a defense system composed of several layers. This review will overview the various strategies plants employ to combat viral infections with main emphasis on the current status of single dominant resistance (R) genes identified against plant viruses and the corresponding avirulence (Avr) genes identified so far. The most common models to explain the mode of action of dominant R genes will be presented. Finally, in brief the hypersensitive response (HR) and extreme resistance (ER), and the functional and structural similarity of R genes to sensors of innate immunity in mammalian cell systems will be described.

de Ronde, Dryas; Butterbach, Patrick; Kormelink, Richard

2014-01-01

314

Proteins and Glycoproteins of Paramyxoviruses: a Comparison of Simian Virus 5, Newcastle Disease Virus, and Sendai Virus  

PubMed Central

The polypeptides of three paramyxoviruses (simian virus 5, Newcastle disease virus, and Sendai virus) were separated by polyacrylamide gel electrophoresis. Glycoproteins were identified by the use of radioactive glucosamine as a carbohydrate precursor. The protein patterns reveal similarities among the three viruses. Each virus contains at least five or six proteins, two of which are glycoproteins. Four of the proteins found in each virus share common features with corresponding proteins in the other two viruses, including similar molecular weights. These four proteins are the nucleocapsid protein (molecular weight 56,000 to 61,000), a larger glycoprotein (molecular weight 65,000 to 74,000), a smaller glycoprotein (molecular weight 53,000 to 56,000), and a major protein which is the smallest protein in each virion (molecular weight 38,000 to 41,000).

Mountcastle, Walter E.; Compans, Richard W.; Choppin, Purnell W.

1971-01-01

315

Detection of reticuloendotheliosis virus in live virus vaccines of poultry.  

PubMed

In vitro and in vivo assays have been used for the detection of reticuloendotheliosis virus (REV) in live virus vaccines of poultry. The presence of REV is confirmed by the demonstration of viral antigen or provirus in chicken embryo fibroblasts (CEFs) or in specific-pathogen-free chickens inoculated with vaccine. Using REV polyclonal or monoclonal antibodies, CEFs inoculated with vaccines can be examined for REV by immunofluorescence or immunoperoxidase staining methods. Cell lysates from such inoculated CEFs can also be used for detection of REV major group-specific antigen (p30) by an enzyme-linked immunoassay. Detection of proviral DNA by polymerase chain reaction (PCR) assays that amplifies the 291 base pairs product of REV LTR has been shown to be a sensitive and specific method for detection of various strains of REV in infected CEFs and in the blood of SPF chickens inoculated with contaminated fowlpox virus (FPV) vaccines. Recently, using PCR tests that amplify REV envelope and REV 3' LTR sequences provided a more accurate assessment of the insertion of REV provirus in FPV than PCR assays that amplify the REV 5' LTR. This paper reviews the most common methods used for testing live virus vaccines of poultry for contamination with REV. PMID:17058506

Fadly, A; Garcia, M C

2006-01-01

316

Expression of rabies virus glycoprotein from a recombinant vaccinia virus  

Microsoft Academic Search

Rabies is one of the oldest diseases known to man, but its successful control has remained elusive. Although effective vaccines of tissue culture origin against rabies do exist1, such preparations are expensive. Live vaccinia virus (VV) recombinants expressing influenza or hepatitis B antigens have recently been used to immunize against these diseases2-4. We have now used this approach to produce

M. P. Kieny; R. Lathe; R. Drillien; D. Spehner; S. Skory; D. Schmitt; T. Wiktor; H. Koprowski; J. P. Lecocq

1984-01-01

317

Boletín del Instituto Nacional del Cáncer - 28 de febrero de 2012  

Cancer.gov

Los artículos originales en inglés están disponibles en las páginas del NCI Cancer Bulletin. El Boletín es una publicación del Instituto Nacional del Cáncer (NCI), una entidad gubernamental de los Estados Unidos creada en 1937.

318

Alterations to influenza virus hemagglutinin cytoplasmic tail modulate virus infectivity.  

PubMed Central

The influenza virus hemagglutinin (HA) contains a cytoplasmic domain that consists of 10 to 11 amino acids, of which five residues have sequence identity for 10 of 13 HA subtypes. To investigate properties of these conserved residues, oligonucleotide-directed mutagenesis was performed, using an HA cDNA of influenza virus A/Udorn/72 (H3N2) to substitute the conserved cysteine residues with other residues, to delete the three C-terminal conserved residues, or to remove the entire cytoplasmic domain. The altered HAs were expressed in eukaryotic cells, and the rates of intracellular transport were examined. It was found that substitution of either conserved cysteine residue within the cytoplasmic domain did not affect the rate of intracellular transport, whereas deletion of residues within the C-terminal domain resulted in delayed cell surface expression. All the altered HAs were biologically active in hemadsorption and fusion assays. To investigate whether the wild-type HA and HAs with altered cytoplasmic tails could complement the influenza virus temperature-sensitive transport-defective HA mutant A/WSN/33 ts61S, the HA cDNAs were expressed by using a transient expression system and released virus was assayed by plaque analysis. The wild-type HA expression resulted in a release of approximately 10(3) PFU of virus per ml. Antibody neutralization of complemented virus indicated that the infectivity was due to incorporation of wild-type H3 HA into ts61S virions. Sucrose density gradient analysis of released virions showed that each of the HA cytoplasmic domain mutants was incorporated into virus particles. Virions containing HAs with substitution of the cysteine residues in the cytoplasmic domain were found to be infectious. However, no infectivity could be detected from virions containing HAs that had deletions in their cytoplasmic domains. Possible roles of the HA cytoplasmic domain in forming protein-protein interactions in virions and their involvement in the initiation of the infection process in cells are discussed. Images

Simpson, D A; Lamb, R A

1992-01-01

319

Persistence of virus lipid signatures upon silicification  

NASA Astrophysics Data System (ADS)

To date there is no known evidence of viruses within the rock record. Their small size and absence of a metabolism has led to the hypothesis that they lack unique biological signatures, and the potential to become preserved. Biosignature research relevant to early Earth has focused on prokaryotic communities; however, the most abundant member of modern ecosystems, viruses, have been ignored. In order to establish a baseline for research on virus biosignatures, we have initiated laboratory research on known lipid-containing viruses. PRD1 is a lipid-containing virus that infects and replicates in Salmonella typhimurium LT2. PRD1 is a 65 nm spherical virus with an internal lipid membrane, which is a few nanometers thick. When the PRD1 virus stock was mixed with a 400 ppm SiO2 (final concentration) solution and incubated for six months. Fourier Transform Infrared Spectroscopy and lipid analysis using gas chromatography revealed that the virus lipids were still detectable despite complete removal of dissolved silica. Free fatty acids were also detected. Titers of infectious PRD1 viruses after six months in the presence of silica decreased 40 times more than without silica. Though virus biosignature research is in its incipient stages, the data suggest that virus lipid signatures are preserved under laboratory conditions and may offer the potential for contribution to the organic geochemical record.

Kyle, J.; Jahnke, L. L.; Stedman, K. M.

2011-12-01

320

Human viruses in sediments, sludges, and soils*  

PubMed Central

Recent studies have provided a greater understanding of the movement of viruses in the environment by their attachment to solids. These studies have focused on solids-associated viruses present in wastewater discharged into the ocean and on viruses in sludge and wastewater that may be retained in soil following their land disposal. Such ocean or land disposal of wastewater and sludge may result in a discharge of one or more of 120 human enteric virus pathogens including those causing poliomyelitis, viral hepatitis A and acute gastroenteritis. Solids-associated viruses in effluents discharged into coastal waters accumulate in bottom sediments, which may contain 10 to 10 000 more virus per unit volume than the overlying seawater. Solids-associated viruses resuspended by water turbulence may be transported from polluted to distant non-polluted recreational or shellfish-growing water. Transmission of viruses causing hepatitis or gastroenteritis may result from contact by bathers or swimmers with these viruses in recreational waters, or from ingestion of raw or improperly cooked shellfish in which the solids-associated virus had been bioaccumulated. The land disposal of sludge and wastewater has a potential of causing infections in farm workers, contamination of crops, pollution of raw potable water sources or infiltration of ground water. Viruses retained on soils can be released by rain water and may contaminate ground water through lateral and vertical movements.

Rao, V. Chalapati; Metcalf, Theodore G.; Melnick, Joseph L.

1986-01-01

321

Psoralen inactivation of influenza and herpes simplex viruses and of virus-infected cells  

SciTech Connect

Psoralen compounds covalently bind to nucleic acids when irradiated with long-wavelength ultraviolet light. This treatment can destroy the infectivity of deoxyribonucleic acid and ribonucleic acid viruses. Two psoralen compounds, 4'-hydroxymethyltrioxsalen and 4'-aminomethyltrioxsalen, were used with long-wavelength ultraviolet light to inactivate cell-free herpes simplex and influenza viruses and to render virus-infected cells noninfectious. This method of inactivation was compared with germicidal (short-wavelength) ultraviolet light irradiation. The antigenicity of the treated, virus-infected, antigen-bearing cells was examined by immunofluorescence and radioimmunoassay and by measuring the capacity of the herpes simplex virus-infected cells to stimulate virus-specific lymphocyte proliferation. The infectivity of the virus-infected cells could be totally eliminated without altering their viral antigenicity. The use of psoralen plus long-wavelength ultraviolet light is well suited to the preparation of noninfectious virus antigens and virus antigen-bearing cells for immunological assays.

Redfield, D.C.; Richman, D.D.; Oxman, M.N.; Kronenberg, L.H.

1981-06-01

322

Tanay virus, a new species of virus isolated from mosquitoes in the Philippines.  

PubMed

In 2005, we isolated a new species of virus from mosquitoes in the Philippines. The virion was elliptical in shape and had a short single projection. The virus was named Tanay virus (TANAV) after the locality in which it was found. TANAV genomic RNA was a 9562 nt+poly-A positive strand, and polycistronic. The longest ORF contained putative RNA-dependent RNA polymerase (RdRP); however, conserved short motifs in the RdRP were permuted. TANAV was phylogenetically close to Negevirus, a recently proposed taxon of viruses isolated from haemophagic insects, and to some plant viruses, such as citrus leprosis virus C, hibiscus green spot virus and blueberry necrotic ring blotch virus. In this paper, we describe TANAV and the permuted structure of its RdRP, and discuss its phylogeny together with those of plant viruses and negevirus. PMID:24646751

Nabeshima, Takeshi; Inoue, Shingo; Okamoto, Kenta; Posadas-Herrera, Guillermo; Yu, Fuxun; Uchida, Leo; Ichinose, Akitoyo; Sakaguchi, Miako; Sunahara, Toshihiko; Buerano, Corazon C; Tadena, Florencio P; Orbita, Ildefonso B; Natividad, Filipinas F; Morita, Kouichi

2014-06-01

323

Repository of Eurasian influenza virus hemagglutinin and neuraminidase reverse genetics vectors and recombinant viruses  

PubMed Central

Reverse genetics can be used to produce recombinant influenza A viruses containing virtually every desired combination of hemagglutinin (HA) and neuraminidase (NA) genes using the virus backbone of choice. Here, a repository of plasmids and recombinant viruses representing all contemporary Eurasian HA and NA subtypes, H1–H16 and N1–N9, was established. HA and NA genes were selected based on sequence analyses of influenza virus genes available from public databases. Prototype Eurasian HA and NA genes were cloned in bidirectional reverse genetics plasmids. Recombinant viruses based on the virus backbone of A/PR/8/34, and containing a variety of HA and NA genes were produced in 293T cells. Virus stocks were produced in MDCK cells and embryonated chicken eggs. These plasmids and viruses may be useful for numerous purposes, including influenza virus research projects, vaccination studies, and to serve as reference reagents in diagnostic settings.

Keawcharoen, J.; Spronken, M.I.J; Vuong, O.; Bestebroer, T.M.; Munster, V.J.; Osterhaus, A.D.M.E; Rimmelzwaan, G.F; Fouchier, R.A.M.

2010-01-01

324

A recombinant influenza virus vaccine expressing the F protein of respiratory syncytial virus.  

PubMed

Infections with influenza and respiratory syncytial virus (RSV) rank high among the most common human respiratory diseases worldwide. Previously, we developed a replication-incompetent influenza virus by replacing the coding sequence of the PB2 gene, which encodes one of the viral RNA polymerase subunits, with that of a reporter gene. Here, we generated a PB2-knockout recombinant influenza virus expressing the F protein of RSV (PB2-RSVF virus) and tested its potential as a bivalent vaccine. In mice intranasally immunized with the PB2-RSVF virus, we detected high levels of antibodies against influenza virus, but not RSV. PB2-RSVF virus-immunized mice were protected from a lethal challenge with influenza virus but experienced severe body weight loss when challenged with RSV, indicating that PB2-RSVF vaccination enhanced RSV-associated disease. These results highlight one of the difficulties of developing an effective bivalent vaccine against influenza virus and RSV infections. PMID:24292020

Fonseca, Wendy; Ozawa, Makoto; Hatta, Masato; Orozco, Esther; Martínez, Máximo B; Kawaoka, Yoshihiro

2014-05-01

325

Wild bird surveillance for avian influenza virus.  

PubMed

Avian influenza (AI) viruses have been isolated from a wide-diversity of free-living avian species representing several taxonomic orders. Isolations are most frequently reported from aquatic birds in the Orders Anseriformes and Charadriiformes, which are believed to be the primordial reservoirs for all AI viruses. Since first recognized in the late 1800s, AI viruses have been an important agent of disease in poultry and, occasionally, of non-gallinaceous birds and mammals. However, recent infections of humans with AI viruses, including highly pathogenic avian influenza (HPAI) H5N1 virus and low pathogenicity H7N9 AI virus in China during 2013, have increased the awareness of their potential to impact agricultural, wildlife, and public health. This chapter is intended to give general concepts and guidelines for planning and implementing surveillance programs for AI virus in wild birds. PMID:24899421

Brown, Justin D; Poulson, Rebecca; Stallknecht, David E

2014-01-01

326

Virus hybrids as nanomaterials for biotechnology.  

PubMed

The current review describes advances in the field of bionanotechnology in which viruses are used to fabricate nanomaterials. Viruses are introduced as protein cages, scaffolds, and templates for the production of biohybrid nanostructured materials where organic and inorganic molecules are incorporated in a precise and a controlled fashion. Genetic engineering enables the insertion or replacement of selected amino acids on virus capsids for uses from bioconjugation to crystal growth. The variety of nanomaterials generated in rod-like and spherical viruses is highlighted for tobacco mosaic virus (TMV), M13 bacteriophage, cowpea chlorotic mottle virus (CCMV), and cowpea mosaic virus (CPMV). Functional biohybrid nanomaterials find applications in biosensing, memory devices, nanocircuits, light-harvesting systems, and nanobatteries. PMID:20688511

Soto, Carissa M; Ratna, Banahalli R

2010-08-01

327

Virus-Induced Aggregates in Infected Cells  

PubMed Central

During infection, many viruses induce cellular remodeling, resulting in the formation of insoluble aggregates/inclusions, usually containing viral structural proteins. Identification of aggregates has become a useful diagnostic tool for certain viral infections. There is wide variety of viral aggregates, which differ by their location, size, content and putative function. The role of aggregation in the context of a specific virus is often poorly understood, especially in the case of plant viruses. The aggregates are utilized by viruses to house a large complex of proteins of both viral and host origin to promote virus replication, translation, intra- and intercellular transportation. Aggregated structures may protect viral functional complexes from the cellular degradation machinery. Alternatively, the activation of host defense mechanisms may involve sequestration of virus components in aggregates, followed by their neutralization as toxic for the host cell. The diversity of virus-induced aggregates in mammalian and plant cells is the subject of this review.

Moshe, Adi; Gorovits, Rena

2012-01-01

328

Comparative inactivation of viruses by chlorine.  

PubMed

The kinetics of inactivation of six enteric viruses plus simian virus 40 and Kilham rat virus by free available chlorine was studied under carefully controlled laboratory conditions. It was found that the different virus types demonstrated a wide range of susceptibility to chlorine disinfection. The rate of inactivation was greater at pH 6 than at pH 10; however, the relative susceptibilities of the different viruses were affected differently by a change in pH, suggesting that the pH influenced both the species of chlorine present and the susceptibility of the different viruses to chlorine. The presence of potassium chloride also affected the susceptibility of viruses to chlorine. PMID:6258473

Engelbrecht, R S; Weber, M J; Salter, B L; Schmidt, C A

1980-08-01

329

Comparative inactivation of viruses by chlorine.  

PubMed Central

The kinetics of inactivation of six enteric viruses plus simian virus 40 and Kilham rat virus by free available chlorine was studied under carefully controlled laboratory conditions. It was found that the different virus types demonstrated a wide range of susceptibility to chlorine disinfection. The rate of inactivation was greater at pH 6 than at pH 10; however, the relative susceptibilities of the different viruses were affected differently by a change in pH, suggesting that the pH influenced both the species of chlorine present and the susceptibility of the different viruses to chlorine. The presence of potassium chloride also affected the susceptibility of viruses to chlorine.

Engelbrecht, R S; Weber, M J; Salter, B L; Schmidt, C A

1980-01-01

330

Virulence Markers of Dengue Viruses.  

National Technical Information Service (NTIS)

Illnesses in humans caused by the four serotypes of dengue virus vary from mild forms i. e. pyrexia of unknown origin (PUO) and dengue fever (DF) to severe forms i.e. dengue hemorrhagic fever and dengue shock syndrome (DHF/DSS). One of the factors that co...

J. L. Hardy S. C. Kliks

1990-01-01

331

Reflections on viruses and cancer  

Microsoft Academic Search

In recent years human and animal cancers have increasingly been shown to have a viral component in their aetiology. Oncogenic viruses will continue to be discovered although with certain cancers there is also an important environmental component, and with others — congenital cancers and cancers of early childhood — an important genetic component. There is thus the probability that ‘cancer’

C. Darcel

1994-01-01

332

Virus-induced autoimmune disease  

Microsoft Academic Search

The braking of tolerance or unresponsiveness to self-antigens, involving the activation of autoreactive lymphocytes, is a critical event leading to autoimmune diseases. The precise mechanisms by which this can occur are mostly unknown. Viruses have been implicated in this process, among other etiological factors, such as genetic predisposition and cytokine activity. Several ways have been proposed by which a viral

Matthias G von Herrath; Michael BA Oldstone

1996-01-01

333

Borna disease virus and schizophrenia  

Microsoft Academic Search

The development of a new serological assay method to detect antibodies in human sera recognizing Borna disease virus (BDV) proteins and a clinical pilot study are presented. Psychiatric patients from a schizophrenia research clinic in Baltimore, Maryland, were examined for antibodies to BDV antigen with traditional indirect immunofluorescence assays (IFA) that used both single and double labeling techniques and also

Royce W. Waltrip; Robert W. Buchanan; Ann Summerfelt; Alan Breier; William T. Carpenter; Nancy L. Bryant; Steven A. Rubin; Kathryn M. Carbone

1995-01-01

334

Evaluating the protective efficacy of a trivalent vaccine containing Akabane virus, Aino virus and Chuzan virus against Schmallenberg virus infection  

PubMed Central

Schmallenberg virus (SBV), an arthropod borne pathogen, spread rapidly throughout the majority of Europe since 2011. It can cause a febrile disease, milk drop, diarrhea, and fetal malformation in ruminants. SBV, a member of the Simbu serogroup within the genus Orthobunyavirus, is closely related to Akabane virus (AKAV) and Aino virus (AINOV) among others. In the present study, 4 Holstein-Friesian calves were immunized twice four weeks apart with a multivalent, inactivated vaccine against AKAV and AINOV. Another 4 calves were kept as unvaccinated controls. All animals were clinically, serologically and virologically examined before and after challenge infection with SBV. AKAV- and AINOV-specific neutralizing antibodies were detected one week before challenge infection, while SBV-specific antibodies were detectable only thereafter. SBV genome was detected in all vaccinated animals and 3 out of 4 controls in serum samples taken after challenge infection. In conclusion, the investigated vaccine was not able to prevent an SBV-infection. Thus, vaccines for other related Simbu serogroup viruses can not substitute SBV-specific vaccines as an instrument for disease control.

2013-01-01

335

Herpes Simplex Virus: Dry Mass.  

National Technical Information Service (NTIS)

Dry mass of herpes simplex virus particles was measured by quantitative electron microscopy after isolation by surface spreading and critical-point drying of infected cells. The core weighed about 2 x 10 to the minus 16th power gram, the empty naked capsi...

F. Lampert G. F. Bahr A. S. Rabson

1969-01-01

336

Recombination in Hepatitis C Virus  

PubMed Central

Hepatitis C virus (HCV) is a Flavivirus with a positive-sense, single-stranded RNA genome of about 9,600 nucleotides. It is a major cause of liver disease, infecting almost 200 million people all over the world. Similarly to most RNA viruses, HCV displays very high levels of genetic diversity which have been used to differentiate six major genotypes and about 80 subtypes. Although the different genotypes and subtypes share basic biological and pathogenic features they differ in clinical outcomes, response to treatment and epidemiology. The first HCV recombinant strain, in which different genome segments derived from parentals of different genotypes, was described in St. Petersburg (Russia) in 2002. Since then, there have been only a few more than a dozen reports including descriptions of HCV recombinants at all levels: between genotypes, between subtypes of the same genotype and even between strains of the same subtype. Here, we review the literature considering the reasons underlying the difficulties for unequivocally establishing recombination in this virus along with the analytical methods necessary to do it. Finally, we analyze the potential consequences, especially in clinical practice, of HCV recombination in light of the coming new therapeutic approaches against this virus.

Gonzalez-Candelas, Fernando; Lopez-Labrador, F. Xavier; Bracho, Maria Alma

2011-01-01

337

HTLV III Virus Isolation Studies.  

National Technical Information Service (NTIS)

A systematic viral isolation study has been performed on peripheral blood lymphocytes obtained from Air Force personnel positive for antibodies to the human immunodeficiency virus (HIV-1) as assessed by HIV-ELISA and/or immunoblot assays. The co-culture t...

T. C. Chanh

1989-01-01

338

Mayaro Fever Virus, Brazilian Amazon  

PubMed Central

In February 2008, a Mayaro fever virus (MAYV) outbreak occurred in a settlement in Santa Barbara municipality, northern Brazil. Patients had rash, fever, and severe arthralgia lasting up to 7 days. Immunoglobulin M against MAYV was detected by ELISA in 36 persons; 3 MAYV isolates sequenced were characterized as genotype D.

Azevedo, Raimunda S.S.; Silva, Eliana V.P.; Carvalho, Valeria L.; Rodrigues, Sueli G.; Neto, Joaquim P. Nunes; Monteiro, Hamilton A.O.; Peixoto, Victor S.; Chiang, Jannifer O.; Nunes, Marcio R.T.

2009-01-01

339

Viruses Associated with Human Cancer  

PubMed Central

It is estimated that viral infections contribute to 15–20% of all human cancers. As obligatory intracellular parasites, viruses encode proteins that reprogram host cellular signaling pathways that control proliferation, differentiation, cell death, genomic integrity, and recognition by the immune system. These cellular processes are governed by complex and redundant regulatory networks and are surveyed by sentinel mechanisms that ensure that aberrant cells are removed from the proliferative pool. Given that the genome size of a virus is highly restricted to ensure packaging within an infectious structure, viruses must target cellular regulatory nodes with limited redundancy and need to inactivate surveillance mechanisms that would normally recognize and extinguish such abnormal cells. In many cases, key proteins in these same regulatory networks are subject to mutation in non-virally associated diseases and cancers. Oncogenic viruses have thus served as important experimental models to identify and molecularly investigate such cellular networks. These include the discovery of oncogenes and tumor suppressors, identification of regulatory networks that are critical for maintenance of genomic integrity, and processes that govern immune surveillance.

McLaughlin-Drubin, Margaret E.; Munger, Karl

2008-01-01

340

Satellite Tobacco Mosaic Virus (STMV)  

NASA Technical Reports Server (NTRS)

The structure of the Satellite Tobacco Mosaic Virus (STMV)--one of the smallest viruses known--has been successfully deduced using STMV crystals grown aboard the Space Shuttle in 1992 and 1994. The STMV crystals were up to 30 times the volume of any seen in the laboratory. At the same time they gave the best resolution data ever obtained on any virus crystal. STMV is a small icosahedral plant virus, consisting of a protein shell made up of 60 identical protein subunits of molecular weight 17,500. Particularly noteworthy is the fact that, in contrast to the crystal grown on Earth, the crystals grown under microgravity conditions were viusally perfect, with no striations or clumping of crystals. Furthermore, the X-ray diffraction data obtained from the space-grown crystals was of a much higher quality than the best data available at that time from ground-based crystals. This computer model shows the external coating or capsid. STMV is used because it is a simple protein to work with; studies are unrelated to tobacco. Credit: Dr. Alex McPherson, Univeristy of California at Irvin.

2000-01-01

341

Turnip Yellow Mosaic Virus Structure  

NASA Technical Reports Server (NTRS)

The bumpy exterior of the turnip yellow mosaic virus (TYMV) protein coat, or capsid, was defined in detail by Dr. Alexander McPherson of the University of California, Irvin using protein crystallized in space for analysis on Earth. TYMV is an icosahedral virus constructed from 180 copies of the same protein arranged into 12 clusters of five proteins (pentamers), and 20 clusters of six proteins (hexamers). The final TYMV structure led to the enexpected hypothesis that the virus release its RNA by essentially chemical-mechanical means. Most viruses have farly flat coats, but in TYMV, the fold in each protein, called the jellyroll, is clustered at the points where the protein pentamers and hexamers join. The jellyrolls are almost standing on end, producing a bumpy surface with knobs at all of the pentamers and hexamers. At the inside surface of the pentamers is a void that is not present at the hexamers. The coating had been seen in early studies of TYMV, but McPhereson's atomic structure shows much more detail. The inside surface is strikingly, and unexpectedly, different than the outside. While the pentamers contain a central viod on the inside, the hexameric units contain peptides liked to each other, forming a ring or, more accurately, rings to fill the voild. Credit: Dr. Alexander McPherson, University of California, Irvine.

2000-01-01

342

Characterization of Reemerging Chikungunya Virus  

Microsoft Academic Search

An unprecedented epidemic of chikungunya virus (CHIKV) infection recently started in countries of the Indian Ocean area, causing an acute and painful syndrome with strong fever, asthenia, skin rash, polyarthritis, and lethal cases of encephalitis. The basis for chikungunya disease and the tropism of CHIKV remain unknown. Here, we describe the replication characteristics of recent clinical CHIKV strains. Human epithelial

Marion Sourisseau; Clémentine Schilte; Nicoletta Casartelli; Céline Trouillet; Florence Guivel-Benhassine; Dominika Rudnicka; Nathalie Sol-Foulon; Karin Le Roux; Marie-Christine Prevost; Hafida Fsihi; Marie-Pascale Frenkiel; Fabien Blanchet; Philippe V. Afonso; Pierre-Emmanuel Ceccaldi; Simona Ozden; Antoine Gessain; Isabelle Schuffenecker; Bruno Verhasselt; Alessia Zamborlini; Ali Saïb; Felix A. Rey; Fernando Arenzana-Seisdedos; Philippe Desprès; Alain Michault; Matthew L. Albert; Olivier Schwartz

2007-01-01

343

A virus-based biocatalyst  

NASA Astrophysics Data System (ADS)

Virus particles are probably the most precisely defined nanometre-sized objects that can be formed by protein self-assembly. Although their natural function is the storage and transport of genetic material, they have more recently been applied as scaffolds for mineralization and as containers for the encapsulation of inorganic compounds. The reproductive power of viruses has been used to develop versatile analytical methods, such as phage display, for the selection and identification of (bio)active compounds. To date, the combined use of self-assembly and reproduction has not been used for the construction of catalytic systems. Here we describe a self-assembled system based on a plant virus that has its coat protein genetically modified to provide it with a lipase enzyme. Using single-object and bulk catalytic studies, we prove that the virus-anchored lipase molecules are catalytically active. This anchored biocatalyst, unlike man-made supported catalysts, has the capability to reproduce itself in vivo, generating many independent catalytically active copies.

Carette, Noëlle; Engelkamp, Hans; Akpa, Eric; Pierre, Sebastien J.; Cameron, Neil R.; Christianen, Peter C. M.; Maan, Jan C.; Thies, Jens C.; Weberskirch, Ralf; Rowan, Alan E.; Nolte, Roeland J. M.; Michon, Thierry; van Hest, Jan C. M.

2007-04-01

344

Powassan Virus Encephalitis, Minnesota, USA  

PubMed Central

Powassan virus (POWV) is a rare tick-borne agent of encephalitis in North America. Historically, confirmed cases occurred mainly in the northeastern United States. Since 2008, confirmed cases in Minnesota and Wisconsin have increased. We report a fatal case of POWV encephalitis in Minnesota. POWV infection should be suspected in tick-exposed patients with viral encephalitis.

Sonnesyn, Steven

2012-01-01

345

Ecological Studies on Amapari Virus.  

National Technical Information Service (NTIS)

(1) Amapari virus has been isolated from only two of the many species of rodents and other vertebrates studied at Serra do Navio, Amapa, Brazil. These are Oryzomys capito goeldii and Neacomys guianae. The isolation rate for each species over 4 years was c...

F. P. Pinheiro J. P. Woodall

1969-01-01

346

Antigenic variants of rabies virus  

Microsoft Academic Search

Rabies viruses isolated from different animal species in various parts of the world were in the past considered to be antigenically closely related. Only when the antibodies produced in animals immunized with whole virions or viral components were assayed by the plaque reduction method, were some minor differences detected in the antigenic composition of various rabies strains (1). On the

T. J. WIKTOR; H. KOPROWSKI

1980-01-01

347

Viruses: are they living entities?  

PubMed

The essence (living or nonliving entities) of viruses has today become an aporia, i.e. a difficulty inherent in reasoning because they shared four fundamental characteristics with livings (multiplication, genetic information, mutation and evolution) without having the capacity to have an independent life. For much time, however, they were considered minuscule pathogenetic micro-organisms in observance of Koch and Pasteur's 'germ theory' albeit no microbiologist could show their existence except their filterability and pathogenetic action. Only some voices based on experimental results raised against this dogmatic view, in particular those of Beijerinck, Baur and Mrowka, without dipping effectively into the dominant theory. The discovery relative to their nucleoprotein nature made between 1934 and 1936 (Schlesinger as for the phage, and Bawden and co-operators as for Tobacco mosaic virus; TMV), together with the first demonstrations of their structures thanks to electron microscopy (from 1939 onwards) started on casting a new light on their true identity, which could be more clearly identified when, from 1955 onwards, phage and TMV proved to be decisive factors to understand the strategies of replication of the genetic material. Following the new knowledge, the theoretical view relative to viruses changed rather radically and the current view looks on these pathogenetic agents as nonliving aggregates of macromolecules provided with biological properties. There is, however, a current of thought, made explicitly by Lwoff that places viruses as compromise between living and non living and, perhaps, as primitive forms of life which have had great importance for the evolution of cellular life. At any rate, viruses are peculiar entities whose importance cannot be unacknowledged. PMID:22220354

Pennazio, Sergio

2011-01-01

348

Clinical and biological differences between recurrent herpes simplex virus and varicella-zoster virus infections  

SciTech Connect

The major features that distinguish recurrent herpes simplex virus infections from zoster are illustrated in this article by two case histories. The clinical and epidemiologic features that characterize recurrent herpes simplex virus and varicella-zoster virus infections are reviewed. It is noted that herpesvirus infections are more common and severe in patients with cellular immune deficiency. Each virus evokes both humoral and cellular immune response in the course of primary infection. DNA hybridization studies with RNA probes labelled with sulfur-35 indicate that herpes simplex viruses persist within neurons, and that varicella-zoster virus is found in the satellite cells that encircle the neurons.

Straus, S.E. (National Institute of Allergy and Infectious Diseases, Bethesda, MD (USA))

1989-12-01

349

Clarification and guidance on the proper usage of virus and virus species names  

PubMed Central

A pivotal step in the development of a consistent nomenclature for virus classification was the introduction of the virus species concept by the International Committee on Taxonomy of Viruses (ICTV) in 1991. Yet, almost two decades later, many virologists still are unable to differentiate between virus species and actual viruses. Here we attempt to explain the origin of this confusion, clarify the difference between taxa and physical entities, and suggest simple measures that could be implemented by ICTV Study Groups to make virus taxonomy and nomenclature more accessible to laboratory virologists.

Jahrling, Peter B.

2010-01-01

350

Evidence of Rabies Virus Exposure among Humans in the Peruvian Amazon  

PubMed Central

In May of 2010, two communities (Truenococha and Santa Marta) reported to be at risk of vampire bat depredation were surveyed in the Province Datem del Marañón in the Loreto Department of Perú. Risk factors for bat exposure included age less than or equal to 25 years and owning animals that had been bitten by bats. Rabies virus neutralizing antibodies (rVNAs) were detected in 11% (7 of 63) of human sera tested. Rabies virus ribonucleoprotein (RNP) immunoglobulin G (IgG) antibodies were detected in the sera of three individuals, two of whom were also seropositive for rVNA. Rabies virus RNP IgM antibodies were detected in one respondent with no evidence of rVNA or RNP IgG antibodies. Because one respondent with positive rVNA results reported prior vaccination and 86% (six of seven) of rVNA-positive respondents reported being bitten by bats, these data suggest nonfatal exposure of persons to rabies virus, which is likely associated with vampire bat depredation.

Gilbert, Amy T.; Petersen, Brett W.; Recuenco, Sergio; Niezgoda, Michael; Gomez, Jorge; Laguna-Torres, V. Alberto; Rupprecht, Charles

2012-01-01

351

Reemergence of Vaccinia Virus during Zoonotic Outbreak, Par? State, Brazil  

PubMed Central

In 2010, vaccinia virus caused an outbreak of bovine vaccinia that affected dairy cattle and rural workers in Pará State, Brazil. Genetic analyses identified the virus as distinct from BeAn58058 vaccinia virus (identified in 1960s) and from smallpox vaccine virus strains. These findings suggest spread of autochthonous group 1 vaccinia virus in this region.

de Assis, Felipe L.; Vinhote, Wagner M.; Barbosa, Jose D.; de Oliveira, Cairo H.S.; de Oliveira, Carlos M.G.; Campos, Karinny F.; Silva, Natalia S.; Trindade, Giliane de Souza

2013-01-01

352

Japanese Encephalitis Virus Genotype Replacement, Taiwan, 2009-2010  

PubMed Central

Genotype I of Japanese encephalitis virus first appeared in Taiwan in 2008. Phylogenetic analysis of 37 viruses from pig farms in 2009–2010 classified these viruses into 2 unique subclusters of genotype I viruses and suggested multiple introductions and swift replacement of genotype III by genotype I virus in Taiwan.

Chen, Yi-Ying; Fan, Yi-Chin; Tu, Wu-Chun; Chang, Rey-Yi; Shih, Chen-Chang; Lu, In-Houng; Chien, Maw-Shien; Lee, Wei-Cheng; Chen, Ter-Hsin; Chang, Gwong-Jen

2011-01-01

353

Reemergence of vaccinia virus during Zoonotic outbreak, Pará State, Brazil.  

PubMed

In 2010, vaccinia virus caused an outbreak of bovine vaccinia that affected dairy cattle and rural workers in Pará State, Brazil. Genetic analyses identified the virus as distinct from BeAn58058 vaccinia virus (identified in 1960s) and from smallpox vaccine virus strains. These findings suggest spread of autochthonous group 1 vaccinia virus in this region. PMID:24274374

de Assis, Felipe L; Vinhote, Wagner M; Barbosa, José D; de Oliveira, Cairo H S; de Oliveira, Carlos M G; Campos, Karinny F; Silva, Natália S; Trindade, Giliane de Souza

2013-12-01

354

Determinants of the Host Range of Feline Leukaemia Viruses  

Microsoft Academic Search

SUMMARY Feline leukaemia viruses of subgroups B and C multiply in human and canine cells, while subgroup A viruses do not. This host range restriction is determined by the virus envelope and operates at the level of virus entry into the cell. Subgroup A virus genomes are expressed and replicated when they are introduced within B subgroup envelopes into human

O. Jarrett; HELEN M. LAIRD; D. Hay

1973-01-01

355

A Dynamic Immunity-Based Model for Computer Virus Detection  

Microsoft Academic Search

Internet provides a fertile medium for new breeds of computer viruses. Many people who have access to a wealth of information via Internet are attacked by more computer viruses than they can effectively process. We present a dynamic computer virus detection model that can detect known viruses and previously unknown viruses to prevent information systems from damage. This model is

Yu Zhang; Tao Li; Renchao Qin

2008-01-01

356

HUMAN IMMUNODEFICIENCY VIRUS (HIV) DISEASE HUMAN IMMUNODEFICIENCY VIRUS AND HEPATITIS C VIRUS CO-INFECTION  

Microsoft Academic Search

Hepatitis C virus (HCV) infection is a major cause of liver disease and hepatocellular carci- noma worldwide, as well as the leading cause of liver transplantations in the United States. As a result of similar modes of transmission, approximately 30% of HIV-infected individuals are co-infected with HCV. Among intravenous drug users, almost 90% of people infected with HIVare also infected

Stacey R. VLAHAKIS

357

Oncogenicity of avian leukosis viruses of different subgroups and of mutants of sarcoma viruses.  

PubMed Central

Leukosis viruses of seven subgroups were tested for oncogenicity in chickens susceptible to virus infection and to development of lymphoid leukosis (LL) tumors. All subgroup A viruses and the subgroup B virus tested produced a high incidence of LL and other related neoplasms. Viruses of subgroup C and RAV-61 of subgroup F produced a low level of LL. The RAV-50 of subgroup D produced osteopetrosis. In these tests, the viruses of subgroup E and G and one virus of subgroup F were not pathogenic, possibly because infection was not established in the chickens, the chickens were not susceptible to tumor development by these viruses, or the viruses lacked oncogenicity. All temperature-sensitive mutants of Rous sarcoma virus produced sarcomas, but the level varied. One nontransforming mutant produced sarcomas, and the other three tested produced LL. All three mutants that cause cells to grow as colonies in agar produced a high incidence of sarcomas. Thus, sarcoma viruses, by back-mutation, may lose the ability to transform cells in vitro, to make cells grow in agar colonies, or to induce sarcomas in vivo, yet they retain the ability to produce LL. Conversely, it was previously shown that leukosis viruses may be changed into viruses that transform cells in vitro and produce sarcomas in vivo by suitable passage in chicks.

Purchase, H G; Okazaki, W; Vogt, P K; Hanafusa, H; Burmester, B R; Crittenden, L B

1977-01-01

358

West Nile virus: North American experience  

USGS Publications Warehouse

West Nile virus, a mosquito-vectored flavivirus of the Japanese encephalitis serogroup, was first detected in North America following an epizootic in the New York City area in 1999. In the intervening 11 years since the arrival of the virus in North America, it has crossed the contiguous USA, entered the Canadian provinces bordering the USA, and has been reported in the Caribbean islands, Mexico, Central America and, more recently, South America. West Nile virus has been reported in over 300 species of birds in the USA and has caused the deaths of thousands of birds, local population declines of some avian species, the clinical illness and deaths of thousands of domestic horses, and the clinical disease in over 30 000 Americans and the deaths of over 1000. Prior to the emergence of West Nile virus in North America, St. Louis encephalitis virus and Dengue virus were the only other known mosquito-transmitted flaviviruses in North America capable of causing human disease. This review will discuss the North American experience with mosquito-borne flavivirus prior to the arrival of West Nile virus, the entry and spread of West Nile virus in North America, effects on wild bird populations, genetic changes in the virus, and the current state of West Nile virus transmission.

Hofmeister, Erik K.

2011-01-01

359

The modulation of apoptosis by oncogenic viruses  

PubMed Central

Transforming viruses can change a normal cell into a cancer cell during their normal life cycle. Persistent infections with these viruses have been recognized to cause some types of cancer. These viruses have been implicated in the modulation of various biological processes, such as proliferation, differentiation and apoptosis. The study of infections caused by oncogenic viruses had helped in our understanding of several mechanisms that regulate cell growth, as well as the molecular alterations leading to cancer. Therefore, transforming viruses provide models of study that have enabled the advances in cancer research. Viruses with transforming abilities, include different members of the Human Papillomavirus (HPV) family, Hepatitis C virus (HCV), Human T-cell Leukemia virus (HTLV-1), Epstein Barr virus (EBV) and Kaposi’s Sarcoma Herpesvirus (KSHV). Apoptosis, or programmed cell death, is a tightly regulated process that plays an important role in development and homeostasis. Additionally, it functions as an antiviral defense mechanism. The deregulation of apoptosis has been implicated in the etiology of diverse diseases, including cancer. Oncogenic viruses employ different mechanisms to inhibit the apoptotic process, allowing the propagation of infected and damaged cells. During this process, some viral proteins are able to evade the immune system, while others can directly interact with the caspases involved in apoptotic signaling. In some instances, viral proteins can also promote apoptosis, which may be necessary for an accurate regulation of the initial stages of infection.

2013-01-01

360

Recombination in Eukaryotic Single Stranded DNA Viruses  

PubMed Central

Although single stranded (ss) DNA viruses that infect humans and their domesticated animals do not generally cause major diseases, the arthropod borne ssDNA viruses of plants do, and as a result seriously constrain food production in most temperate regions of the world. Besides the well known plant and animal-infecting ssDNA viruses, it has recently become apparent through metagenomic surveys of ssDNA molecules that there also exist large numbers of other diverse ssDNA viruses within almost all terrestrial and aquatic environments. The host ranges of these viruses probably span the tree of life and they are likely to be important components of global ecosystems. Various lines of evidence suggest that a pivotal evolutionary process during the generation of this global ssDNA virus diversity has probably been genetic recombination. High rates of homologous recombination, non-homologous recombination and genome component reassortment are known to occur within and between various different ssDNA virus species and we look here at the various roles that these different types of recombination may play, both in the day-to-day biology, and in the longer term evolution, of these viruses. We specifically focus on the ecological, biochemical and selective factors underlying patterns of genetic exchange detectable amongst the ssDNA viruses and discuss how these should all be considered when assessing the adaptive value of recombination during ssDNA virus evolution.

Martin, Darren P.; Biagini, Philippe; Lefeuvre, Pierre; Golden, Michael; Roumagnac, Philippe; Varsani, Arvind

2011-01-01

361

LCM virus infection of cells in vitro*  

PubMed Central

Most mammalian cells cultivated in vitro can be infected with lymphocytic choriomeningitis (LCM) virus. In addition to infectious virus, the cells produce antigenic material that fixes complement in the presence of antibody and is precipitated by antiserum. Intracellular antigen can also be demonstrated by the immunofluorescence procedure. When infected cells are viewed with the electron microscope, viral structures are seen either budding from or in association with the cell membranes. Immunoelectron microscopy, immunofluorescence, and cytotoxicity tests reveal virus-specific antigens on the surface of intact cells. Virus multiplication may be succeeded by cytolysis. Two LCM virus-specific antigens (or antigenic groups) can at present be distinguished. One corresponds to the infectious virus; the other is the complement-fixing “soluble” antigen. This extractable complement-fixing activity is produced by infected cells and is also a structural component of the infectious virus. It is not represented on the surface of either the virion or the infected cell. The cytolytic potential of LCM virus varies and is dependent on its previous passage history. Cytolytic and “attenuated” variants are able to initiate persistent infection of Mus musculus. Together with infectious virus, particles are produced that temporarily protect cells against standard virus. They appear to be by-products of virus multiplication, not in the sense of deletion mutants but of virus structures insufficiently equipped for their own active or passive replication, though capable of interfering with infectious virus. No evidence has been found for the generation of “defective interfering” particles, though their presence has not yet been excluded. ImagesFig. 3Fig. 4Fig. 5Fig. 6Fig. 7Fig. 8

Lehmann-Grube, F.; Popescu, M.; Schaefer, H.; Gschwender, H. H.

1975-01-01

362

An Automatic Unpacking Method for Computer Virus Effective in the Virus Filter Based on Paul Graham's Bayesian Theorem  

Microsoft Academic Search

Recently, the appearance frequency of computer virus variants has increased. Updates to virus information using the normal pattern matching method are increasingly unable to keep up with the speed at which viruses occur, since it takes time to extract the characteristic patterns for each virus. Therefore, a rapid, automatic virus detection algorithm using static code analysis is necessary. However, recent

Dengfeng Zhang; Naoshi Nakaya; Yuuji Koui; Hitoaki Yoshida

2009-01-01

363

Boletín del Instituto Nacional del Cáncer - 01-05-2010  

Cancer.gov

Al caminar por los pasillos del nuevo centro oncológico integral en la sede de Ciencias Médicas de la Universidad de Puerto Rico (UPR) en San Juan, uno debe mantener los ojos abiertos. La mujer que pasa caminando vigorosamente podría ser la doctora Marcia Roxana Cruz-Correa, y no debe uno perderse la oportunidad de conocerla.

364

Boletín del Instituto Nacional del Cáncer - 04-27-2010  

Cancer.gov

Cada vez es más evidente que los esfuerzos mundiales de salud de mayor éxito dependen no solo del aporte de las mentes más brillantes, sino de la colaboración entre ellas para marcar la diferencia en el escenario global. Este enfoque es el motor impulsor detrás de una asociación excepcional con el NCI, financiada en parte por Susan G.

365

La Investigación del Cáncer en América Latina  

Cancer.gov

Este programa busca fomentar los esfuerzos locales y mundiales de prevención, diagnóstico y tratamiento del cáncer facilitando la creación de una infraestructura integral para la investigación del cáncer en América Latina.

366

Instantánea del cáncer de cuello uterino  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de cuello uterino; así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

367

Instantánea del cáncer de seno (mama)  

Cancer.gov

Información sobre las tendencias de incidencia, mortalidad y financiamiento del NCI sobre el cáncer de seno (mama); así como ejemplos de actividades del NCI y adelantos en la investigación de este tipo de cáncer.

368

Improved method for counting virus and virus like particles.  

PubMed

An improved method for counting virus and virus like particles by electron microscopy (EM) was developed. The procedure involves the determination of the absolute concentration of pure or semi-pure particles once deposited evenly on EM grids using either centrifugation or antibody capture techniques. The counting of particles was done with a Microfiche unit which enlarged approximately 50 x the image of particles on a developed negative film which had been taken at a relatively low magnification (2500 x) by EM. Initially, latex particles of a known concentration were counted using this approach, to prove the accuracy of the technique. The latex particles were deposited evenly on an EM grid using centrifugation (Modified Beckmen EM-90 Airfuge technique). Subsequently, recombinant Bluetongue virus (BTV) core-like particles (CLPs) captured by a Monoclonal antibody using a novel sample loading method were counted by the Microfiche unit method and by a direct EM method. Comparison of the simplified counting method developed with a conventional method, showed good agreement. The method is simple, accurate, rapid, and reproducible when used with either pure particles or with particles from crude cell culture extracts. PMID:9002073

Zheng, Y Z; Webb, R; Greenfield, P F; Reid, S

1996-12-01

369

Human immunodeficiency virus, herpes virus infections, and pulmonary vascular disease  

PubMed Central

The following state-of-the-art seminar was delivered as part of the Aspen Lung Conference on Pulmonary Hypertension and Vascular Diseases held in Aspen, Colorado in June 2012. This paper will summarize the lecture and present results from a nonhuman primate model of infection with Simian (Human) Immunodeficiency Virus - nef chimeric virions as well as the idea that polymorphisms in the HIV-1 nef gene may be driving the immune response that results in exuberant inflammation and aberrant endothelial cell (EC) function. We will present data gathered from primary HIV nef isolates where we tested the biological consequences of these polymorphisms and how their presence in human populations may predict patients at risk for developing this disease. In this article, we also discuss how a dysregulated immune system, in conjunction with a viral infection, could contribute to pulmonary arterial hypertension (PAH). Both autoimmune diseases and some viruses are associated with defects in the immune system, primarily in the function of regulatory T cells. These T-cell defects may be a common pathway in the formation of plexiform lesions. Regardless of the route by which viruses may lead to PAH, it is important to recognize their role in this rare disease.

Flores, Sonia C.; Almodovar, Sharilyn

2013-01-01

370

Occurrence and prevalence of seven bee viruses in Apis mellifera and Apis cerana apiaries in China  

Microsoft Academic Search

Populations of Apis mellifera and Apis cerana in China were surveyed for seven bee viruses: acute bee paralysis virus (ABPV), black queen cell virus (BQCV), chronic bee paralysis virus (CBPV), deformed wing virus (DWV), Kashmir bee virus (KBV), sacbrood virus (SBV), and Isreal acute paralysis virus (IAPV). No KBV was detected from any samples of the two species. In A.

Hongxia Ai; Xun Yan; Richou Han

371

Pseudotyping of vesicular stomatitis virus with the envelope glycoproteins of highly pathogenic avian influenza viruses.  

PubMed

Pseudotype viruses are useful for studying the envelope proteins of harmful viruses. This work describes the pseudotyping of vesicular stomatitis virus (VSV) with the envelope glycoproteins of highly pathogenic avian influenza viruses. VSV lacking the homotypic glycoprotein (G) gene (VSV?G) was used to express haemagglutinin (HA), neuraminidase (NA) or the combination of both. Propagation-competent pseudotype viruses were only obtained when HA and NA were expressed from the same vector genome. Pseudotype viruses containing HA from different H5 clades were neutralized specifically by immune sera directed against the corresponding clade. Fast and sensitive reading of test results was achieved by vector-mediated expression of GFP. Pseudotype viruses expressing a mutant VSV matrix protein showed restricted spread in IFN-competent cells. This pseudotype system will facilitate the detection of neutralizing antibodies against virulent influenza viruses, circumventing the need for high-level biosafety containment. PMID:24814925

Zimmer, Gert; Locher, Samira; Berger Rentsch, Marianne; Halbherr, Stefan J

2014-08-01

372

Impact of anti-virus software on computer virus dynamical behavior  

NASA Astrophysics Data System (ADS)

The impact of anti-virus software on the spreading of computer virus is investigated via developing a mathematical model in this paper. Considering the anti-virus software may not be effective, as it may be an outdated version, and then the computers may be infected with a reduced incidence rate. According to the method of next generation matrix, the basic reproduction number is derived. By introducing appropriate Lyapunov function and the Routh stability criterion, acquiring the stability conditions of the virus-free equilibrium and virus equilibrium. The effect of anti-virus software and disconnecting rate on the spreading of virus are also analyzed. When combined with the numerical results, a set of suggestions are put forward for eradicating virus effectively.

Sun, Mei; Li, Dandan; Han, Dun; Jia, Changsheng

2014-05-01

373

Identification of Novel Viruses Using VirusHunter -- an Automated Data Analysis Pipeline  

PubMed Central

Quick and accurate identification of microbial pathogens is essential for both diagnosis and response to emerging infectious diseases. The advent of next-generation sequencing technology offers an unprecedented platform for rapid sequencing-based identification of novel viruses. We have developed a customized bioinformatics data analysis pipeline, VirusHunter, for the analysis of Roche/454 and other long read Next generation sequencing platform data. To illustrate the utility of VirusHunter, we performed Roche/454 GS FLX titanium sequencing on two unclassified virus isolates from the World Reference Center for Emerging Viruses and Arboviruses (WRCEVA). VirusHunter identified sequences derived from a novel bunyavirus and a novel reovirus in the two samples respectively. Further sequence analysis demonstrated that the viruses were novel members of the Phlebovirus and Orbivirus genera. Both Phlebovirus and Orbivirus genera include many economic important viruses or serious human pathogens.

Zhao, Guoyan; Krishnamurthy, Siddharth; Cai, Zhengqiu; Popov, Vsevolod L.; Travassos da Rosa, Amelia P.; Guzman, Hilda; Cao, Song; Virgin, Herbert W.; Tesh, Robert B.; Wang, David

2013-01-01

374

Evolution and ecology of influenza A viruses.  

PubMed Central

In this review we examine the hypothesis that aquatic birds are the primordial source of all influenza viruses in other species and study the ecological features that permit the perpetuation of influenza viruses in aquatic avian species. Phylogenetic analysis of the nucleotide sequence of influenza A virus RNA segments coding for the spike proteins (HA, NA, and M2) and the internal proteins (PB2, PB1, PA, NP, M, and NS) from a wide range of hosts, geographical regions, and influenza A virus subtypes support the following conclusions. (i) Two partly overlapping reservoirs of influenza A viruses exist in migrating waterfowl and shorebirds throughout the world. These species harbor influenza viruses of all the known HA and NA subtypes. (ii) Influenza viruses have evolved into a number of host-specific lineages that are exemplified by the NP gene and include equine Prague/56, recent equine strains, classical swine and human strains, H13 gull strains, and all other avian strains. Other genes show similar patterns, but with extensive evidence of genetic reassortment. Geographical as well as host-specific lineages are evident. (iii) All of the influenza A viruses of mammalian sources originated from the avian gene pool, and it is possible that influenza B viruses also arose from the same source. (iv) The different virus lineages are predominantly host specific, but there are periodic exchanges of influenza virus genes or whole viruses between species, giving rise to pandemics of disease in humans, lower animals, and birds. (v) The influenza viruses currently circulating in humans and pigs in North America originated by transmission of all genes from the avian reservoir prior to the 1918 Spanish influenza pandemic; some of the genes have subsequently been replaced by others from the influenza gene pool in birds. (vi) The influenza virus gene pool in aquatic birds of the world is probably perpetuated by low-level transmission within that species throughout the year. (vii) There is evidence that most new human pandemic strains and variants have originated in southern China. (viii) There is speculation that pigs may serve as the intermediate host in genetic exchange between influenza viruses in avian and humans, but experimental evidence is lacking. (ix) Once the ecological properties of influenza viruses are understood, it may be possible to interdict the introduction of new influenza viruses into humans. Images

Webster, R G; Bean, W J; Gorman, O T; Chambers, T M; Kawaoka, Y

1992-01-01

375

Full Genome Sequencing of Corriparta Virus, Identifies California Mosquito Pool Virus as a Member of the Corriparta virus Species  

PubMed Central

The species Corriparta virus (CORV), within the genus Orbivirus, family Reoviridae, currently contains six virus strains: corriparta virus MRM1 (CORV-MRM1); CS0109; V654; V370; Acado virus and Jacareacanga virus. However, lack of neutralization assays, or reference genome sequence data has prevented further analysis of their intra-serogroup/species relationships and identification of individual serotypes. We report whole-genome sequence data for CORV-MRM1, which was isolated in 1960 in Australia. Comparisons of the conserved, polymerase (VP1), sub-core-shell ‘T2’ and core-surface ‘T13’ proteins encoded by genome segments 1, 2 and 8 (Seg-1, Seg-2 and Seg-8) respectively, show that this virus groups with the other mosquito borne orbiviruses. However, highest levels of nt/aa sequence identity (75.9%/91.6% in Seg-2/T2: 77.6%/91.7% in Seg-8/T13, respectively) were detected between CORV-MRM1 and California mosquito pool virus (CMPV), an orbivirus isolated in the USA in 1974, showing that they belong to the same virus species. The data presented here identify CMPV as a member of the Corriparta virus species and will facilitate identification of additional CORV isolates, diagnostic assay design and epidemiological studies.

Belaganahalli, Manjunatha N.; Maan, Sushila; Maan, Narender S.; Nomikou, Kyriaki; Guimera, Marc; Brownlie, Joe; Tesh, Robert; Attoui, Houssam; Mertens, Peter P. C.

2013-01-01

376

Geología y registros magnéticos entre arroyo La Tapera y Santa Clara del Mar, Mar del Plata  

Microsoft Academic Search

Geology and magnetic records between Arroyo La Tapera and Santa Clara del Mar, Mar del Plata. Paleomagnetic studies were carried out in Pleistocene-Holocene sedimentary sequences exposed between Arroyo La Tapera and Santa Clara del Mar in Mar del Plata. The sediments exposed in the lower part of the La Tapera and Camet sections, which apparently belong to the Ensenada Formation,

Juan Carlos BIDEGAIN; Margarita L. OSTERRIETH; Adrianus J. VAN VELZEN; Yamile RICO

377

Variabilità interannuale del fi toplancton del Lago di Tovel (Trentino, Italia)  

Microsoft Academic Search

RIASSUNTO - Variabilità interannuale del fi toplancton del Lago di Tovel (Trentino, Italia) - Lo studio del fi toplancton del Lago di Tovel nel periodo 2002-2004 ha avuto come principali obiettivi l'analisi della variabilità interannuale delle dinamiche stagionali nel Bacino Principale e nella Baia Rossa, il confronto tra le associazioni fi toplanctoniche attuali e passate (prima e dopo la scomparsa

Monica TOLOTTI; Dámaso CALLIARI; Flavio CORRADINI

378

Structure of Immature West Nile Virus?  

PubMed Central

The structure of immature West Nile virus particles, propagated in the presence of ammonium chloride to block virus maturation in the low-pH environment of the trans-Golgi network, was determined by cryo-electron microscopy (cryo-EM). The structure of these particles was similar to that of immature West Nile virus particles found as a minor component of mature virus samples (naturally occurring immature particles [NOIPs]). The structures of mature infectious flaviviruses are radically different from those of the immature particles. The similarity of the ammonium chloride-treated particles and NOIPs suggests either that the NOIPs have not undergone any conformational change during maturation or that the conformational change is reversible. Comparison with the cryo-EM reconstruction of immature dengue virus established the locations of the N-linked glycosylation sites of these viruses, verifying the interpretation of the reconstructions of the immature flaviviruses.

Zhang, Ying; Kaufmann, Barbel; Chipman, Paul R.; Kuhn, Richard J.; Rossmann, Michael G.

2007-01-01

379

Water quality indicators: bacteria, coliphages, enteric viruses.  

PubMed

Water quality through the presence of pathogenic enteric microorganisms may affect human health. Coliform bacteria, Escherichia coli and coliphages are normally used as indicators of water quality. However, the presence of above-mentioned indicators do not always suggest the presence of human enteric viruses. It is important to study human enteric viruses in water. Human enteric viruses can tolerate fluctuating environmental conditions and survive in the environment for long periods of time becoming causal agents of diarrhoeal diseases. Therefore, the potential of human pathogenic viruses as significant indicators of water quality is emerging. Human Adenoviruses and other viruses have been proposed as suitable indices for the effective identification of such organisms of human origin contaminating water systems. This article reports on the recent developments in the management of water quality specifically focusing on human enteric viruses as indicators. PMID:23438312

Lin, Johnson; Ganesh, Atheesha

2013-12-01

380

Securing anti-virus software with virtualization  

US Patent & Trademark Office Database

The subject disclosure relates to systems and methods that secure anti-virus software through virtualization. Anti-virus systems can be maintained separate from user applications and operating system through virtualization. The user applications and operating system run in a guest virtual machine while anti-virus systems are isolated in a secure virtual machine. The virtual machines are partially interdependent such that the anti-virus systems can monitor user applications and operating systems while the anti-virus systems remain free from possible malicious attack originating from a user environment. Further, the anti-virus system is secured against zero-day attacks so that detection and recovery may occur post zero-day.

2012-11-06

381

Development of VIRUS alignment and assembly fixtures  

NASA Astrophysics Data System (ADS)

The Visible Integral-Field Replicable Unit Spectrograph (VIRUS) Instrument is a set of 150+ optical spectrographs to support observations for the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX). We plan to use a production line assembly process to construct the large number of VIRUS units. This allows each sub-assembly of a VIRUS unit to be interchangeable amongst all other VIRUS units. A production line manufacturing procedure will enable various sub-assemblies to be built and tested in parallel. Examples of alignment and assembly fixtures required for the VIRUS manufacturing process include a camera mirror alignment system, a collimator structure assembly device, a collimator mirror mounting tool, and a grating alignment system. In this paper we describe the design of these fixtures and their importance in the VIRUS assembly process.

Collins, Amanda D.; Vattiat, Brian; Marshall, J. L.; Hill, Gary J.; Depoy, D. L.; Lee, Hanshin; Allen, Richard D.; Prochaska, Travis; Villanueva, Steven, Jr.

2010-07-01

382

Virus Infections in the Nervous System  

PubMed Central

Virus infections usually begin in peripheral tissues and can invade the mammalian nervous system (NS), spreading into the peripheral (PNS) and more rarely the central nervous systems (CNS). The CNS is protected from most virus infections by effective immune responses and multi-layer barriers. However, some viruses enter the NS with high efficiency via the bloodstream or by directly infecting nerves that innervate peripheral tissues, resulting in debilitating direct and immune-mediated pathology. Most viruses in the NS are opportunistic or accidental pathogens, but a few, most notably the alpha herpesviruses and rabies virus, have evolved to enter the NS efficiently and exploit neuronal cell biology. Remarkably, the alpha herpesviruses can establish quiescent infections in the PNS, with rare but often fatal CNS pathology. Here we review how viruses gain access to and spread in the well-protected CNS, with particular emphasis on alpha herpesviruses, which establish and maintain persistent NS infections.

Koyuncu, Orkide O.; Hogue, Ian B.; Enquist, Lynn W.

2013-01-01

383

Study of virus by Raman spectroscopy  

NASA Astrophysics Data System (ADS)

Problem of viruses is very actual for nowadays. Some viruses, which are responsible for human of all tumors, are about 15 %. Main purposes this study, early detection virus in live cell without labeling and in the real time by Raman spectroscopy. Micro Raman spectroscopy (mRs) is a technique that uses a Raman spectrometer to measure the spectra of microscopic samples. According to the Raman spectroscopy, it becomes possible to study the metabolites of a live cultured cell without labeling. We used mRs to detect the virus via HEK 293 cell line-infected adenovirus. We obtained raman specters of lives cells with viruses in 24 hours and 7 days after the infection. As the result, there is some biochemical changing after the treatment of cell with virus. One of biochemical alteration is at 1081 cm-1. For the clarification result, we use confocal fluorescent microscopy and transmission electron microscopy (TEM).

Moor, K.; Kitamura, H.; Hashimoto, K.; Sawa, M.; Andriana, B. B.; Ohtani, K.; Yagura, T.; Sato, H.

2013-02-01

384

Virus-Based Chemical and Biological Sensing  

PubMed Central

Viruses have recently proven useful for the detection of target analytes such as explosives, proteins, bacteria, viruses, spores, and toxins with high selectivity and sensitivity. Bacteriophages (often shortened to phages), viruses that specifically infect bacteria, are currently the most studied viruses, mainly because target-specific nonlytic phages (and the peptides and proteins carried by them) can be identified by using the well-established phage display technique, and lytic phages can specifically break bacteria to release cell-specific marker molecules such as enzymes that can be assayed. In addition, phages have good chemical and thermal stability, and can be conjugated with nanomaterials and immobilized on a transducer surface in an analytical device. This Review focuses on progress made in the use of phages in chemical and biological sensors in combination with traditional analytical techniques. Recent progress in the use of virus—nanomaterial composites and other viruses in sensing applications is also high-lighted.

Mao, Chuanbin; Liu, Aihua; Cao, Binrui

2009-01-01

385

Impacts of West Nile Virus on wildlife  

USGS Publications Warehouse

The recent epidemic of West Nile virus in the United States proved to be unexpectedly active and was the largest epidemic of the virus ever recorded. Much remains to be discovered about the ecology and epidemiology of West Nile virus in the United States, including which species are important in maintaining the virus in nature, why some species are more susceptible to lethal infection, and what environmental factors are important in predicting future epidemics. These factors will likely vary regionally, depending on local ecological characteristics. Until scientists better understand the virus and factors influencing its activity, predicting its effects for future seasons is impossible. However, experts are certain about one thing: West Nile virus is here to stay.

Saito, E. K.; Wild, M. A.

2004-01-01

386

Satellite RNAs and Satellite Viruses of Plants  

PubMed Central

The view that satellite RNAs (satRNAs) and satellite viruses are purely molecular parasites of their cognate helper viruses has changed. The molecular mechanisms underlying the synergistic and/or antagonistic interactions among satRNAs/satellite viruses, helper viruses, and host plants are beginning to be comprehended. This review aims to summarize the recent achievements in basic and practical research, with special emphasis on the involvement of RNA silencing mechanisms in the pathogenicity, population dynamics, and, possibly, the origin(s) of these subviral agents. With further research following current trends, the comprehensive understanding of satRNAs and satellite viruses could lead to new insights into the trilateral interactions among host plants, viruses, and satellites.

Hu, Chung-Chi; Hsu, Yau-Heiu; Lin, Na-Sheng

2009-01-01

387

Human influenza virus recognition of sialyloligosaccharides.  

PubMed

Sialic acids are essential components of cell-surface receptors utilized by influenza viruses. To evaluate the recognition of asialic sugar parts of the receptor, three representative strains of human influenza A and B viruses were tested for their binding of a panel of sialyloligosaccharides. The highest affinity binding carbohydrate determinants recognized by the viruses in a context of different core structures were Neu5Ac alpha 2-3Gal for the type B virus, Neu5Ac alpha 2-6 Gal for the H3 subtype virus, and Neu5Ac alpha 2-6Gal beta 1-4GlcNAc for the H1 subtype virus. Penultimate to these determinants parts of the sialyloligosaccharides studied either contributed less significantly to the binding affinity, or interfered with the binding. PMID:7789517

Gambaryan, A S; Piskarev, V E; Yamskov, I A; Sakharov, A M; Tuzikov, A B; Bovin, N V; Nifant'ev, N E; Matrosovich, M N

1995-06-01

388

Comparison of Structural Polypeptides from Vesicular Stomatitis Virus (Indiana and New Jersey Serotypes) and Cocal Virus  

Microsoft Academic Search

SUMMARY The molecular size of the structural proteins of the Indiana and New Jersey serotypes of vesicular stomatitis virus (VSV) and of Cocal virus have been com- pared by co-electrophoresis in SDS-polyacrylamide gel. Virus polypeptides (VP) II, III and V of the Indiana serotype have different electrophoretic mobilities fi'om the corresponding components of the New Jersey serotype. Cocal virus differs

W. H. Wunner; C. R. Pringle

1972-01-01

389

Yellow fever vector live-virus vaccines: West Nile virus vaccine development  

Microsoft Academic Search

By combining molecular-biological techniques with our increased understanding of the effect of gene sequence modification on viral function, yellow fever 17D, a positive-strand RNA virus vaccine, has been manipulated to induce a protective immune response against viruses of the same family (e.g. Japanese encephalitis and dengue viruses). Triggered by the emergence of West Nile virus infections in the New World

Juan Arroyo; Charles A Miller; John Catalan; Thomas P Monath

2001-01-01

390

21 CFR 866.3330 - Influenza virus serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Influenza virus serological reagents. 866...Serological Reagents § 866.3330 Influenza virus serological reagents. (a) Identification. Influenza virus serological reagents are...

2010-04-01

391

21 CFR 866.3305 - Herpes simplex virus serological assays.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Herpes simplex virus serological assays. 866...Serological Reagents § 866.3305 Herpes simplex virus serological assays. (a) Identification . Herpes simplex virus serological assays...

2009-04-01

392

21 CFR 866.3305 - Herpes simplex virus serological assays.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Herpes simplex virus serological assays. 866...Serological Reagents § 866.3305 Herpes simplex virus serological assays. (a) Identification . Herpes simplex virus serological assays...

2010-04-01

393

Epidemiological Investigation of Hart Park and Turlock Viruses in California.  

National Technical Information Service (NTIS)

Turlock (TUR) and Hart Park (HP) viruses were repeatedly isolated from the mosquito Culex tarsails in California. Both viruses were found to replicate in Cx. tarsalis following parenteral inoculation. Once infected, Cx. tarsalis could transmit HP virus to...

T. G. Kziazek

1984-01-01

394

Serologic and Infectivity Studies of Canine Sv-5 Virus (35012).  

National Technical Information Service (NTIS)

The recovery of parainfluenza SV-5 viruses from laboratory and military dogs with respiratory disease was previously reported. The virus was first isolated from rhesus monkey kidney cell cultures and subsequently from man. SV-5 virus appears to infect man...

E. C. Lazar L. J. Swango L. N. Binn

1970-01-01

395

CDC Reports More Cases of Heartland Virus Disease  

MedlinePLUS

... 639-3286 CDC Reports More Cases of Heartland Virus Disease New virus infects six more people and found in second ... six new cases of people sick with Heartland virus: five in Missouri and one in Tennessee. The ...

396

Some aspects of plaque formation by human influenza viruses  

Microsoft Academic Search

Summary Infective influenza virus seems to be essential for plaque production in chick embryo fibroblasts (CEF). With some virus strains, the amounts of virus produced by infected monolayers under an agarose overlay are very small.

C. P. de Sousa; G. Belyavin

1970-01-01

397

Stability at systems of usual differential equations in virus dynamics  

NASA Astrophysics Data System (ADS)

In this paper we discuss different models of differential equations systems, that describe virus dynamics in different situations (HIV-virus and Hepatitis B-virus). We inquire the stability of differential equations. We use theorems of the stability theory.

Schröer, H.

398

21 CFR 866.3380 - Mumps virus serological reagents.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Mumps virus serological reagents. 866.3380... Serological Reagents § 866.3380 Mumps virus serological reagents. (a) Identification. Mumps virus serological reagents consist...

2010-04-01

399

21 CFR 866.3380 - Mumps virus serological reagents.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Mumps virus serological reagents. 866.3380... Serological Reagents § 866.3380 Mumps virus serological reagents. (a) Identification. Mumps virus serological reagents consist...

2009-04-01

400

21 CFR 866.3480 - Respiratory syncytial virus serological reagents.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Respiratory syncytial virus serological reagents. 866.3480... § 866.3480 Respiratory syncytial virus serological reagents. (a) Identification. Respiratory syncytial virus serological reagents are devices...

2013-04-01

401

21 CFR 866.3400 - Parainfluenza virus serological reagents.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 false Parainfluenza virus serological reagents. 866.3400 Section...Reagents § 866.3400 Parainfluenza virus serological reagents. (a) Identification. Parainfluenza virus serological reagents are devices...

2013-04-01

402

9 CFR 113.211 - Feline Rhinotracheitis Vaccine, Killed Virus.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 2010-01-01 false Feline Rhinotracheitis Vaccine, Killed Virus...REQUIREMENTS Killed Virus Vaccines § 113.211 Feline Rhinotracheitis Vaccine, Killed Virus. Feline Rhinotracheitis Vaccine, Killed...

2010-01-01

403

9 CFR 113.203 - Feline Panleukopenia Vaccine, Killed Virus.  

Code of Federal Regulations, 2010 CFR

... 2009-01-01 2009-01-01 false Feline Panleukopenia Vaccine, Killed Virus. 113...REQUIREMENTS Killed Virus Vaccines § 113.203 Feline Panleukopenia Vaccine, Killed Virus. Feline Panleukopenia Vaccine, Killed...

2009-01-01

404

9 CFR 113.203 - Feline Panleukopenia Vaccine, Killed Virus.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 2010-01-01 false Feline Panleukopenia Vaccine, Killed Virus. 113...REQUIREMENTS Killed Virus Vaccines § 113.203 Feline Panleukopenia Vaccine, Killed Virus. Feline Panleukopenia Vaccine, Killed...

2010-01-01

405

9 CFR 113.211 - Feline Rhinotracheitis Vaccine, Killed Virus.  

Code of Federal Regulations, 2010 CFR

... 2009-01-01 2009-01-01 false Feline Rhinotracheitis Vaccine, Killed Virus...REQUIREMENTS Killed Virus Vaccines § 113.211 Feline Rhinotracheitis Vaccine, Killed Virus. Feline Rhinotracheitis Vaccine, Killed...

2009-01-01

406

Worries Over Computer "Viruses" Lead Campuses to Issue Guidelines.  

ERIC Educational Resources Information Center

Computer viruses are programs that propagate themselves from disk to disk and destroy programs or information files. Several universities have recently reported virus outbreaks. Some suggestions for avoiding the viruses are provided. (MLW)

Turner, Judith Axler

1987-01-01

407

West Nile Virus in California  

PubMed Central

West Nile virus (WNV) was first isolated in California during July 2003 from a pool of Culex tarsalis collected near El Centro, Imperial County. WNV transmission then increased and spread in Imperial and Coachella Valleys, where it was tracked by isolation from pools of Cx. tarsalis, seroconversions in sentinel chickens, and seroprevalence in free-ranging birds. WNV then dispersed to the city of Riverside, Riverside County, and to the Whittier Dam area of Los Angeles County, where it was detected in dead birds and pools of Cx. pipiens quinquefasciatus. By October, WNV was detected in dead birds collected from riparian corridors in Los Angeles, west to Long Beach, and through inland valleys south from Riverside to San Diego County. WNV was reported concurrently from Arizona in mid-August and from Baja, Mexico, in mid-November. Possible mechanisms for virus introduction, amplification, and dispersal are discussed.

Lothrop, Hugh; Chiles, Robert; Madon, Minoo; Cossen, Cynthia; Woods, Leslie; Husted, Stan; Kramer, Vicki; Edman, John

2004-01-01

408

Características del desplazamiento forzado en Colombia  

Microsoft Academic Search

RESUMEN El presente estudio es una contribución a la explicación y comprensión de la problemática del desplazamiento forzado interno en Colombia, fenómeno considerado como violación masiva y múltiple de los derechos humanos, circunstancia de lesa humanidad además de ser infracción grave del Derecho Internacional Humanitario. Se identificaron los antecedentes históricos, la dinámica regional del fenómeno, la existencia de factores estructurales

Henry Fernández Pinto; JIMMY SÁNCHEZ REYEZ

2011-01-01

409

Replication of avian influenza viruses in humans  

Microsoft Academic Search

Summary Volunteers inoculated with avian influenza viruses belonging to subtypes currently circulating in humans (H1N1 and H3N2) were largely refractory to infection. However 11 out of 40 volunteers inoculated with the avian subtypes, H4N8, H6N1, and H10N7, shed virus and had mild clinical symptoms: they did not produce a detectable antibody response. This was presumably because virus multiplication was limited

A. S. Beare; R. G. Webster

1991-01-01

410

Transgenic gene silencing strategies for virus control  

Microsoft Academic Search

Co-suppression of transgenes and their homologous viral sequences by RNA silencing is a powerful strategy for achieving high-level\\u000a virus resistance in plants. This review provides a brief overview of RNA silencing mechanisms in plants and discusses important\\u000a transgene construct design features underpinning successful RNA silencing-mediated transgenic virus control. Application of\\u000a those strategies to protect horticultural and field crops from virus

R. G. Dietzgen; N. Mitter

2006-01-01

411

RNA Virus Reverse Genetics and Vaccine Design  

PubMed Central

RNA viruses are capable of rapid spread and severe or potentially lethal disease in both animals and humans. The development of reverse genetics systems for manipulation and study of RNA virus genomes has provided platforms for designing and optimizing viral mutants for vaccine development. Here, we review the impact of RNA virus reverse genetics systems on past and current efforts to design effective and safe viral therapeutics and vaccines.

Stobart, Christopher C.; Moore, Martin L.

2014-01-01

412

Virus-induced gene complementation in tomato  

PubMed Central

Virus-induced gene complementation (VIGC), a plant virus technology based on Potato virus X for transient overexpression of endogenous genes complemented tomato mutants, resulting in non-ripening fruits to ripen. This efficient “gain-of-function” approach involves no stable transformation, and reveals a fruit-specific transcriptional network that may exist among key transcription factors in modulating tomato ripening. Thus, VIGC represents a novel and feasible strategy for gene functional analysis in plants.

Kong, Jinhua; Chen, Weiwei; Shen, Jiajia; Qin, Cheng; Lai, Tongfei; Zhang, Pengcheng; Wang, Ying; Wu, Chaoqun; Yang, Xin; Hong, Yiguo

2013-01-01

413

Dose-Response Model for Lassa Virus  

Microsoft Academic Search

This article develops dose-response models for Lassa fever virus using data sets found in the open literature. Dose-response data were drawn from two studies in which guinea pigs were given subcutaneous and aerosol exposure to Lassa virus. In one study, six groups of inbred guinea pigs were inoculated subcutaneously with doses of Lassa virus and five groups of out-bred guinea

Sushil B. Tamrakar; Charles N. Haas

2008-01-01

414

RNA virus reverse genetics and vaccine design.  

PubMed

RNA viruses are capable of rapid spread and severe or potentially lethal disease in both animals and humans. The development of reverse genetics systems for manipulation and study of RNA virus genomes has provided platforms for designing and optimizing viral mutants for vaccine development. Here, we review the impact of RNA virus reverse genetics systems on past and current efforts to design effective and safe viral therapeutics and vaccines. PMID:24967693

Stobart, Christopher C; Moore, Martin L

2014-01-01

415

Virus-induced gene complementation in tomato.  

PubMed

Virus-induced gene complementation (VIGC), a plant virus technology based on Potato virus X for transient overexpression of endogenous genes complemented tomato mutants, resulting in non-ripening fruits to ripen. This efficient "gain-of-function" approach involves no stable transformation, and reveals a fruit-specific transcriptional network that may exist among key transcription factors in modulating tomato ripening. Thus, VIGC represents a novel and feasible strategy for gene functional analysis in plants. PMID:24305652

Kong, Jinhua; Chen, Weiwei; Shen, Jiajia; Qin, Cheng; Lai, Tongfei; Zhang, Pengcheng; Wang, Ying; Wu, Chaoqun; Yang, Xin; Hong, Yiguo

2013-11-01

416

Reference gene selection for quantitative real-time PCR analysis in virus infected cells: SARS corona virus, Yellow fever virus, Human Herpesvirus6, Camelpox virus and Cytomegalovirus infections  

Microsoft Academic Search

Ten potential reference genes were compared for their use in experiments investigating cellular mRNA expression of virus infected cells. Human cell lines were infected with Cytomegalovirus, Human Herpesvirus-6, Camelpox virus, SARS coronavirus or Yellow fever virus. The expression levels of these genes and the viral replication were determined by real-time PCR. Genes were ranked by the BestKeeper tool, the GeNorm

Aleksandar Radoni?; Stefanie Thulke; Hi-Gung Bae; Marcel A Müller; Wolfgang Siegert; Andreas Nitsche

2005-01-01

417

Structure of Turnip Yellow Mosaic Virus  

Microsoft Academic Search

IN this communication we report some of the results of the early stages of an X-ray diffraction study of crystals of turnip yellow mosaic virus1,2. The two most important conclusions from the interpretation of the X-ray diagrams concern: (a) the packing of the virus particles in the crystal; and (b) the arrangement of protein sub-units in the individual virus particle.

A. Klug; J. T. Finch; Rosalind E. Franklin

1957-01-01

418

Intrusion Detection for Viruses and Worms  

Microsoft Academic Search

The global economic impact of computer viruses and worms soars into the range of billions of dollars every year according to reports by Computer Economics. Since early1999 when the Melissa macro virus began the trend of spreading quickly via mass e-mailing, viruses and worms have become a common and persistent problem for all computer users. In the 2003 CSI\\/FBI Computer

Thomas M. Chen

419

West Nile Virus Neuroinvasive Disease  

Microsoft Academic Search

West Nile virus (WNV), first recognized in North America in 1999, was responsible for the largest arboviral epidemic of human\\u000a encephalitis in history and continues to be the most frequent cause of epidemic meningoencephalitis in North America. WNV\\u000a neuroinvasive disease (WNND) occurs in fewer than 1% of infected individuals, with presentations including aseptic meningitis,\\u000a encephalitis, and poliomyelitis. Between 1999 and

Roberta L. DeBiasi

2011-01-01

420

Flow cytometric detection of viruses  

Microsoft Academic Search

Representatives from several different virus families (Baculoviridae, Herpesviridae, Myoviridae, Phycodnaviridae, Picornaviridae, Podoviridae, Retroviridae, and Siphoviridae) were stained using a variety of highly fluorescent nucleic acid specific dyes (SYBR Green I, SYBR Green II, OliGreen, PicoGreen) and examined using a standard flow cytometer equipped with a standard 15 mW argon-ion laser. The highest green fluorescence intensities were obtained using SYBR Green

Corina P. D. Brussaard; Dominique Marie; Gunnar Bratbak

2000-01-01

421

Probiotics in respiratory virus infections.  

PubMed

Viral respiratory infections are the most common diseases in humans. A large range of etiologic agents challenge the development of efficient therapies. Research suggests that probiotics are able to decrease the risk or duration of respiratory infection symptoms. However, the antiviral mechanisms of probiotics are unclear. The purpose of this paper is to review the current knowledge on the effects of probiotics on respiratory virus infections and to provide insights on the possible antiviral mechanisms of probiotics. A PubMed and Scopus database search was performed up to January 2014 using appropriate search terms on probiotic and respiratory virus infections in cell models, in animal models, and in humans, and reviewed for their relevance. Altogether, thirty-three clinical trials were reviewed. The studies varied highly in study design, outcome measures, probiotics, dose, and matrices used. Twenty-eight trials reported that probiotics had beneficial effects in the outcome of respiratory tract infections (RTIs) and five showed no clear benefit. Only eight studies reported investigating viral etiology from the respiratory tract, and one of these reported a significant decrease in viral load. Based on experimental studies, probiotics may exert antiviral effects directly in probiotic-virus interaction or via stimulation of the immune system. Although probiotics seem to be beneficial in respiratory illnesses, the role of probiotics on specific viruses has not been investigated sufficiently. Due to the lack of confirmatory studies and varied data available, more randomized, double-blind, and placebo-controlled trials in different age populations investigating probiotic dose response, comparing probiotic strains/genera, and elucidating the antiviral effect mechanisms are necessary. PMID:24638909

Lehtoranta, L; Pitkäranta, A; Korpela, R

2014-08-01

422

Del Mar College GIS Program  

NSDL National Science Digital Library

Del Mar College offers a comprehensive geospatial program with certificates and Associates degrees in GIS. This site includes description of the program and courses, along with further contact information. By clicking on the link for "Geographic Information Systems" you may download a PDF with information about the program.

2010-10-28

423

Los cuatro entornos del procomún  

Microsoft Academic Search

Bastan unos minutos para entender la inmensa complejidad que tiene la noción de procomún. Disponemos de muchas definiciones aceptables, aunque las más frecuentes bordean de una u otra manera el problema de la propiedad y la teoría del valor. Cuando decimos que pertenece al procomún todo cuanto es de todos y de nadie a mismo tiempo estamos pensando en un

Antonio Lafuente

424

Vaccination of Macaques against Pathogenic Simian Immunodeficiency Virus with Venezuelan Equine Encephalitis Virus Replicon Particles  

Microsoft Academic Search

Vaccine vectors derived from Venezuelan equine encephalitis virus (VEE) that expressed simian immuno- deficiency virus (SIV) immunogens were tested in rhesus macaques as part of the effort to design a safe and effective vaccine for human immunodeficiency virus. Immunization with VEE replicon particles induced both humoral and cellular immune responses. Four of four vaccinated animals were protected against disease for

NANCY L. DAVIS; IAN J. CALEY; KEVIN W. BROWN; MICHAEL R. BETTS; DAVID M. IRLBECK; KATHRYN M. MCGRATH; MARY J. CONNELL; DAVID C. MONTEFIORI; JEFFREY A. FRELINGER; RONALD SWANSTROM; PHILIP R. JOHNSON; ROBERT E. JOHNSTON

2000-01-01

425

THE STRUCTURE OF CELLS DURING TOBACCO MOSAIC VIRUS REPRODUCTION: Mesophyll Cells Containing Virus Crystals  

Microsoft Academic Search

The submicroscopic organization of mcsophyll ccUs from tobacco leaves systemically in- fected with tobacco mosaic virus (TMV) is described. After fixation with glutaraldchyde and osmium tctroxidc the arrangement of the TMV particles within the crystalline in- clusions is well preserved. Only thc ribonuclcic acid-containing core of thc virus particles is visible in the micrographs. Besides the hexagonal virus crystals, several

L. Kolehmainen; H. ZECH; D. VON WETTSTEIN

1965-01-01

426

Tubule-forming capacity of the movement proteins of alfalfa mosaic virus and brome mosaic virus  

Microsoft Academic Search

The structural phenotype of the movement proteins (MPs) of two representatives of the Bromoviridae, alfalfa mosaic virus (AMV) and brome mosaic virus (BMV), was studied in protoplasts. Immunofluor- escence microscopy showed that the MPs of these viruses, for which there has been no evidence of a tubule-guided mechanism, assemble into long tubular structures at the surface of the infected protoplast.

D. T. J. Kasteel; N. N. van der Wel; K. A. J. Jansen; R. W. Goldbach; J. W. M. van Lent

427

Antibody Responses against Xenotropic Murine Leukemia Virus-Related Virus Envelope in a Murine Model  

Microsoft Academic Search

BackgroundXenotropic murine leukemia virus-related virus (XMRV) was recently discovered to be the first human gammaretrovirus that is associated with chronic fatigue syndrome and prostate cancer (PC). Although a mechanism for XMRV carcinogenesis is yet to be established, this virus belongs to the family of gammaretroviruses well known for their ability to induce cancer in the infected hosts. Since its original

Natalia Makarova; Chunxia Zhao; Yuanyuan Zhang; Sushma Bhosle; Suganthi Suppiah; Jeanne M. Rhea; Natalia Kozyr; Rebecca S. Arnold; Hinh Ly; Ross J. Molinaro; Tristram G. Parslow; Eric Hunter; Dennis Liotta; John Petros; Jerry L. Blackwell; Shabaana Khader

2011-01-01

428

Cell Type Mediated Resistance of Vesicular Stomatitis Virus and Sendai Virus to Ribavirin  

Microsoft Academic Search

Ribavirin (RBV) is a synthetic nucleoside analog with broad spectrum antiviral activity. Although RBV is approved for the treatment of hepatitis C virus, respiratory syncytial virus, and Lassa fever virus infections, its mechanism of action and therapeutic efficacy remains highly controversial. Recent reports show that the development of cell-based resistance after continuous RBV treatment via decreased RBV uptake can greatly

Nirav R. Shah; Amanda Sunderland; Valery Z. Grdzelishvili; Ron A. M. Fouchier

2010-01-01

429

Incorporation of High Levels of Chimeric Human Immunodeficiency Virus Envelope Glycoproteins into Virus-Like Particles  

Microsoft Academic Search

The human immunodeficiency virus (HIV) envelope (Env) protein is incorporated into HIV virions or virus-like particles (VLPs) at very low levels compared to the glycoproteins of most other enveloped viruses. To test factors that influence HIV Env particle incorporation, we generated a series of chimeric gene constructs in which the coding sequences for the signal peptide (SP), transmembrane (TM), and

Bao-Zhong Wang; Weimin Liu; Sang-Moo Kang; Munir Alam; Chunzi Huang; Ling Ye; Yuliang Sun; Yingying Li; Denise L. Kothe; Peter Pushko; Terje Dokland; Barton F. Haynes; Gale Smith; Beatrice H. Hahn; Richard W. Compans

2007-01-01

430

Comparisons of Belmont Virus, a Possible Bunyavirus Unique to Australia, with Bunyamwera Virus  

Microsoft Academic Search

SUMMARY Belmont virus is an arbovirus isolated from mosquitoes and has a preference for marsupial hosts. The diameter of virions by negative staining (122 nm before fixation and 91 nm after fixation) was greater than that of Bunyamwera virus (94 nm and 79 nm respectively). However, the particles of both viruses appeared morphologically identical and sedimented at the same rate

D. A. McPHEEt; E. G. Westaway

1981-01-01

431

A comparative study of O'nyong nyong virus with Chikungunya virus and plaque variants  

Microsoft Academic Search

Summary Two plaque variants of Chikungunya (CHIK) virus were serologically compared with O'nyong nyong (ONN) virus in order to elucidate the reported one way antigenic relationships between the two viruses. Three different hypotheses are examined and evidence is shown to support one of them.

A. C. Chanas; Z. Hubalek; B. K. Johnson; D. I. H. Simpson

1979-01-01

432

A Virus Similar to Human Hepatitis B Virus Associated with Hepatitis and Hepatoma in Woodchucks  

Microsoft Academic Search

Particles with properties similar to those associated with human hepatitis B were found in serum from woodchucks with chronic hepatitis and hepatocellular carcinoma. It is suggested that woodchuck hepatitis virus is a second member of a novel class of viruses represented by the human hepatitis B virus.

Jesse Summers; Jo Marie Smolec; Robert Snyder

1978-01-01

433

Priming and boosting immunity to respiratory syncytial virus by recombinant replication-defective vaccinia virus MVA  

Microsoft Academic Search

Intranasal and intramuscular immunizations of mice with the highly attenuated MVA strain of vaccinia virus expressing the respiratory syncytial virus (RSV) F or G glycoprotein induced higher RSV antibody titers than those achieved by infection with RSV and greatly restricted the replication of RS challenge virus in both the upper and lower respiratory tracts. In addition, a recombinant MVA expressing

Linda S. Wyatt; Stephen S. Whitehead; Katherine A. Venanzi; Brian R. Murphy; Bernard Moss

1999-01-01

434

Complete nucleotide sequence of Kashmir bee virus and comparison with acute bee paralysis virus  

Microsoft Academic Search

The complete nucleotide sequence of a novel virus is presented here together with serological evidence that it belongs to Kashmir bee virus (KBV). Analysis reveals that KBV is a cricket paralysis-like virus (family Dicistroviridae: genus Cripavirus), with a non-structural polyprotein open reading frame in the 59 portion of the genome separated by an intergenic region from a structural polyprotein open

J. R. de Miranda; M. Drebot; S. Tyler; M. Shen; C. E. Cameron; D. B. Stoltz; S. M. Camazine

2004-01-01

435

Analysis of human immunodeficiency virus in semen: indications of a genetically distinct virus reservoir  

Microsoft Academic Search

It is well established that HIV is found in semen, either as cell-free or cell associated virus, yet many questions remain about the source of the virus. A number of factors, including anatomic features of the male reproductive tract, the restricted access of the immune system to the germ cell compartment, and the results from sexually transmitted virus studies, suggest

Randal A Byrn; Ann A Kiessling

1998-01-01

436

Foamy Virus Budding and Release  

PubMed Central

Like all other viruses, a successful egress of functional particles from infected cells is a prerequisite for foamy virus (FV) spread within the host. The budding process of FVs involves steps, which are shared by other retroviruses, such as interaction of the capsid protein with components of cellular vacuolar protein sorting (Vps) machinery via late domains identified in some FV capsid proteins. Additionally, there are features of the FV budding strategy quite unique to the spumaretroviruses. This includes secretion of non-infectious subviral particles and a strict dependence on capsid-glycoprotein interaction for release of infectious virions from the cells. Virus-like particle release is not possible since FV capsid proteins lack a membrane-targeting signal. It is noteworthy that in experimental systems, the important capsid-glycoprotein interaction could be bypassed by fusing heterologous membrane-targeting signals to the capsid protein, thus enabling glycoprotein-independent egress. Aside from that, other systems have been developed to enable envelopment of FV capsids by heterologous Env proteins. In this review article, we will summarize the current knowledge on FV budding, the viral components and their domains involved as well as alternative and artificial ways to promote budding of FV particle structures, a feature important for alteration of target tissue tropism of FV-based gene transfer systems.

Hutter, Sylvia; Zurnic, Irena; Lindemann, Dirk

2013-01-01

437

Satellite Tobacco Mosaic Virus Structure  

NASA Technical Reports Server (NTRS)

The structure of the Satellite Tobacco Mosaic Viurus (STMV)--one of the smallest viruses known--has been successfully reduced using STMV crystals grown aboard the Space Shuttle in 1992 and 1994. The STMV crystals were up to 30 times the volume of any seen in the laboratory. At the time they gave the best resolution data ever obtained on any virus crystal. STMV is a small icosahedral plant virus, consisting of a protein shell made up of 60 identical protein subunits of molecular weight 17,500. Particularly noteworthy is the fact that, in contrast to the crystals grown on Earth, the crystals grown under microgravity conditions were visually perfect, with no striations or clumping of crystals. Furthermore, the x-ray diffraction data obtained from the space-grown crystals was of a much higher quality than the best data available at that time from ground-based crystals. This stylized ribbon model shows the protein coat in white and the nucleic acid in yellow. STMV is used because it is a simple protein to work with; studies are unrelated to tobacco. Credit: Dr. Alex McPherson, University of California at Irvin.

2000-01-01

438

West Nile virus drug discovery.  

PubMed

The outbreak of West Nile virus (WNV) in 1999 in the USA, and its continued spread throughout the Americas, parts of Europe, the Middle East and Africa, underscored the need for WNV antiviral development. Here, we review the current status of WNV drug discovery. A number of approaches have been used to search for inhibitors of WNV, including viral infection-based screening, enzyme-based screening, structure-based virtual screening, structure-based rationale design, and antibody-based therapy. These efforts have yielded inhibitors of viral or cellular factors that are critical for viral replication. For small molecule inhibitors, no promising preclinical candidate has been developed; most of the inhibitors could not even be advanced to the stage of hit-to-lead optimization due to their poor drug-like properties. However, several inhibitors developed for related members of the family Flaviviridae, such as dengue virus and hepatitis C virus, exhibited cross-inhibition of WNV, suggesting the possibility to re-purpose these antivirals for WNV treatment. Most promisingly, therapeutic antibodies have shown excellent efficacy in mouse model; one of such antibodies has been advanced into clinical trial. The knowledge accumulated during the past fifteen years has provided better rationale for the ongoing WNV and other flavivirus antiviral development. PMID:24300672

Lim, Siew Pheng; Shi, Pei-Yong

2013-12-01

439

West Nile Virus Drug Discovery  

PubMed Central

The outbreak of West Nile virus (WNV) in 1999 in the USA, and its continued spread throughout the Americas, parts of Europe, the Middle East and Africa, underscored the need for WNV antiviral development. Here, we review the current status of WNV drug discovery. A number of approaches have been used to search for inhibitors of WNV, including viral infection-based screening, enzyme-based screening, structure-based virtual screening, structure-based rationale design, and antibody-based therapy. These efforts have yielded inhibitors of viral or cellular factors that are critical for viral replication. For small molecule inhibitors, no promising preclinical candidate has been developed; most of the inhibitors could not even be advanced to the stage of hit-to-lead optimization due to their poor drug-like properties. However, several inhibitors developed for related members of the family Flaviviridae, such as dengue virus and hepatitis C virus, exhibited cross-inhibition of WNV, suggesting the possibility to re-purpose these antivirals for WNV treatment. Most promisingly, therapeutic antibodies have shown excellent efficacy in mouse model; one of such antibodies has been advanced into clinical trial. The knowledge accumulated during the past fifteen years has provided better rationale for the ongoing WNV and other flavivirus antiviral development.

Lim, Siew Pheng; Shi, Pei-Yong

2013-01-01

440

Infectious laryngotracheitis virus in chickens  

PubMed Central

Infectious laryngotracheitis (ILT) is an important respiratory disease of chickens and annually causes significant economic losses in the poultry industry world-wide. ILT virus (ILTV) belongs to alphaherpesvirinae and the Gallid herpesvirus 1 species. The transmission of ILTV is via respiratory and ocular routes. Clinical and post-mortem signs of ILT can be separated into two forms according to its virulence. The characteristic of the severe form is bloody mucus in the trachea with high mortality. The mild form causes nasal discharge, conjunctivitis, and reduced weight gain and egg production. Conventional polymerase chain reaction (PCR), nested PCR, real-time PCR, and loop-mediated isothermal amplification were developed to detect ILTV samples from natural or experimentally infected birds. The PCR combined with restriction fragment length polymorphism (RFLP) can separate ILTVs into several genetic groups. These groups can separate vaccine from wild type field viruses. Vaccination is a common method to prevent ILT. However, field isolates and vaccine viruses can establish latent infected carriers. According to PCR-RFLP results, virulent field ILTVs can be derived from modified-live vaccines. Therefore, modified-live vaccine reversion provides a source for ILT outbreaks on chicken farms. Two recently licensed commercial recombinant ILT vaccines are also in use. Other recombinant and gene-deficient vaccine candidates are in the developmental stages. They offer additional hope for the control of this disease. However, in ILT endemic regions, improved biosecurity and management practices are critical for improved ILT control.

Ou, Shan-Chia; Giambrone, Joseph J

2012-01-01

441

Reversible Inactivation and Desiccation Tolerance of Silicified Viruses  

PubMed Central

Long-distance host-independent virus dispersal is poorly understood, especially for viruses found in isolated ecosystems. To demonstrate a possible dispersal mechanism, we show that bacteriophage T4, archaeal virus Sulfolobus spindle-shaped virus Kamchatka, and vaccinia virus are reversibly inactivated by mineralization in silica under conditions similar to volcanic hot springs. In contrast, bacteriophage PRD1 is not silicified. Moreover, silicification provides viruses with remarkable desiccation resistance, which could allow extensive aerial dispersal.

Laidler, James R.; Shugart, Jessica A.; Cady, Sherry L.; Bahjat, Keith S.

2013-01-01

442

Electronic Parameters of Mesoporous Silicon Upon Adsorption of Plant Viruses  

NASA Astrophysics Data System (ADS)

Changes in the electronic parameters of mesoporous silicon upon adsorption of nematodetransmitted polyhedral (NEPO) viruses of plant [tomato ringspot virus (TORSV), grapevine virus A (GVA), and grapevine fan leaf virus (GFLV)] measured at room temperature are investigated. The adsorption of these viruses affected essentially on the electronic characteristic of the porous material. The measurement of the electronic characteristics of porous silicon can be applied to the creation of detectors for the presence of viruses in a given environment.

Vashpanov, Yuriy; Son, Jung-Young; Kwack, Kae-Dal; Shin, Seung-Jung

2008-06-01

443

Complete Genome Sequence of a Street Rabies Virus from Mexico  

PubMed Central

A canine rabies virus (RABV) has been used as a street rabies virus in laboratory investigations. Its entire genome was sequenced and found to be closely related to that of canine RABV circulating in Mexico. Sequence comparison indicates that the virus is closely related to those in the “cosmopolitan” group, with high homology (89 to 93%) to clade I of rabies viruses. The virus is now termed dog rabies virus-Mexico (DRV-Mexico).

Zhang, Guoqing

2012-01-01

444

Genome organisation and sequence comparison suggest intraspecies incongruence in M RNA of Watermelon bud necrosis virus.  

PubMed

Watermelon bud necrosis virus (WBNV), a member of the genus Tospovirus, family Bunyaviridae is an important viral pathogen in watermelon cultivation in India. The complete genome sequence properties of WBNV are not available. In the present study, the complete M RNA sequence and the genome organisation of a WBNV isolate infecting watermelon in Delhi (WBNV-wDel) were determined. The M RNA was 4,794 nucleotides (nt) long and potentially coded for a movement protein (NSm) of 34.22 kDa (307 amino acids) on the viral sense strand and a Gn/Gc glycoprotein precursor of 127.15 kDa (1,121 amino acids) on the complementary strand. The two open reading frames were separated by an intergenic region of 402 nt. The 5' and 3' untranslated regions were 55 and 47 nt long, respectively, containing complementary termini typical of tospoviruses. WBNV-wDel was most closely related (79.1% identity) to Groundnut bud necrosis virus, an important tospovirus that occurs in several crops in India, and was different (63.3-75.2% identity) from the other cucurbit-infecting tospoviruses known to occur in Taiwan and Japan. Sequence analysis of NSm and Gn/Gc revealed phylogenetic incongruence between WBNV-wDel and another isolate originating from central India (WBNV-Wm-Som isolate). The Wm-Som isolate showed evolutionary divergence from the wDel isolate in the Gn/Gc protein (74.6% identity) potentially due to recombination with the other tospoviruses that are known to occur in India. This is the first report of a comparison of complete sequences of M RNA of WBNV. PMID:20480193

Kumar, Rakesh; Mandal, B; Geetanjali, A S; Jain, R K; Jaiwal, P K

2010-08-01

445

[Rift Valley fever virus: evolution in progress].  

PubMed

Several viruses now circulating in tropical zones around the globe are potential threats for ever-increasing human populations even in temperate zones that have long remained unaffected. The mechanisms underlying transport and transmission, which can be enhanced by human activity, can be even stronger in zones where factors needed to support development of these viruses, i.e., hosts, reservoirs and vectors, are already present. This possibility has been illustrated by dengue virus, and now by the rapid spread of the Chikungunya virus on Reunion Island in 2005 and then in Italy in 2007. The spreading of Chikungunya virus despite its mild reputation had a major unexpected impact. It showed that the evolution of the virus, whether a cause or consequence of observed events, could be determinant. The risk of extension of more pathogenic viruses due to similar mechanisms must be considered as a possibility. In this regard the Rift Valley fever virus, that already involves a large area and has a major reservoir, is one of the viruses that deserves close surveillance. PMID:19702138

Tolou, H; Plumet, S; Leparc-Goffart, I; Couissinier-Paris, P

2009-06-01

446

Epidemiology of Hepatitis C Virus (HCV) Infection  

PubMed Central

Hepatitis C virus remains a large health care burden to the world. Incidence rates across the world fluctuate and are difficult to calculate given the asymptomatic, often latent nature of the disease prior to clinical presentation. Prevalence rates across the world have changed as well with more countries aware of transfusion-related hepatitis C and more and more evidence supporting intravenous drug use as the leading risk factor of spread of the virus. This article reviews current hepatitis C virus prevalence and genotype data and examines the different risk factors associated with the virus.

Sy, Theodore; Jamal, M. Mazen

2006-01-01

447

RNA Viruses: ROS-Mediated Cell Death  

PubMed Central

Reactive oxygen species (ROS) are well known for being both beneficial and deleterious. The main thrust of this review is to investigate the role of ROS in ribonucleic acid (RNA) virus pathogenesis. Much evidences has accumulated over the past decade, suggesting that patients infected with RNA viruses are under chronic oxidative stress. Changes to the body's antioxidant defense system, in relation to SOD, ascorbic acid, selenium, carotenoids, and glutathione, have been reported in various tissues of RNA-virus infected patients. This review focuses on RNA viruses and retroviruses, giving particular attention to the human influenza virus, Hepatitis c virus (HCV), human immunodeficiency virus (HIV), and the aquatic Betanodavirus. Oxidative stress via RNA virus infections can contribute to several aspects of viral disease pathogenesis including apoptosis, loss of immune function, viral replication, inflammatory response, and loss of body weight. We focus on how ROS production is correlated with host cell death. Moreover, ROS may play an important role as a signal molecule in the regulation of viral replication and organelle function, potentially providing new insights in the prevention and treatment of RNA viruses and retrovirus infections.

Reshi, Mohammad Latif; Su, Yi-Che; Hong, Jiann-Ruey

2014-01-01

448

Radioimmunoassay of measles virus hemagglutinin protein G.  

PubMed

Guinea pig and rabbit antisera from animals immunized with purified measles virus hemagglutinin (G) protein were used to establish a solid-phase four-layer radioimmunoassay for quantitative measurement of the G protein. The sensitive of the assay was 2 ng of purified G protein, and 200 micrograms of protein from uninfected Vero cells neither decreased the sensitivity nor reacted non-specifically in the assay. Radioimmunoassay standard dose-response curves were established and unknown values interpolated from these using the logit program of a desktop computer. Using this procedure, a measles virus growth curve in infected Vero cells was determined by measurement of G protein production. Under these same conditions, hemagglutination was not sensitive enough to detect early hemagglutinin production. Viral antigens in canine distemper virus, Newcastle disease virus, parainfluenza viruses 1-4, simian virus 5, and respiratory syncytial virus-infected cell lysates did not cross-react in the radioimmunoassay. A small degree of cross-reactivity was detected with mumps viral antigens, both with Vero cell-derived (wild-type strain) and egg-derived (Enders strain) purified virus preparations and with a cell lysate antigen prepared from wild-type mumps virus-infected Vero cells. PMID:7130334

Lund, G A; Salmi, A A

1982-08-01

449

Viruses as Modulators of Mitochondrial Functions  

PubMed Central

Mitochondria are multifunctional organelles with diverse roles including energy production and distribution, apoptosis, eliciting host immune response, and causing diseases and aging. Mitochondria-mediated immune responses might be an evolutionary adaptation by which mitochondria might have prevented the entry of invading microorganisms thus establishing them as an integral part of the cell. This makes them a target for all the invading pathogens including viruses. Viruses either induce or inhibit various mitochondrial processes in a highly specific manner so that they can replicate and produce progeny. Some viruses encode the Bcl2 homologues to counter the proapoptotic functions of the cellular and mitochondrial proteins. Others modulate the permeability transition pore and either prevent or induce the release of the apoptotic proteins from the mitochondria. Viruses like Herpes simplex virus 1 deplete the host mitochondrial DNA and some, like human immunodeficiency virus, hijack the host mitochondrial proteins to function fully inside the host cell. All these processes involve the participation of cellular proteins, mitochondrial proteins, and virus specific proteins. This review will summarize the strategies employed by viruses to utilize cellular mitochondria for successful multiplication and production of progeny virus.

Anand, Sanjeev K.; Tikoo, Suresh K.

2013-01-01

450

Flexible filamentous virus structure from fiber diffraction  

SciTech Connect

Fiber diffraction data have been obtained from Narcissus mosaic virus, a potexvirus from the family Flexiviridae, and soybean mosaic virus (SMV), a potyvirus from the family Potyviridae. Analysis of the data in conjunction with cryo-electron microscopy data allowed us to determine the symmetry of the viruses and to make reconstructions of SMV at 19 {angstrom} resolution and of another potexvirus, papaya mosaic virus, at 18 {angstrom} resolution. These data include the first well-ordered data ever obtained for the potyviruses and the best-ordered data from the potexviruses, and offer the promise of eventual high resolution structure determinations.

Stubbs, Gerald; Kendall, Amy; McDonald, Michele; Bian, Wen; Bowles, Timothy; Baumgarten, Sarah; McCullough, Ian; Shi, Jian; Stewart, Phoebe; Bullitt, Esther; Gore, David; Ghabrial, Said (IIT); (BU-M); (Vanderbilt); (Kentucky)

2008-10-24

451

Inhibition of Enveloped Viruses Infectivity by Curcumin  

PubMed Central

Curcumin, a natural compound and ingredient in curry, has antiinflammatory, antioxidant, and anticarcinogenic properties. Previously, we reported that curcumin abrogated influenza virus infectivity by inhibiting hemagglutination (HA) activity. This study demonstrates a novel mechanism by which curcumin inhibits the infectivity of enveloped viruses. In all analyzed enveloped viruses, including the influenza virus, curcumin inhibited plaque formation. In contrast, the nonenveloped enterovirus 71 remained unaffected by curcumin treatment. We evaluated the effects of curcumin on the membrane structure using fluorescent dye (sulforhodamine B; SRB)-containing liposomes that mimic the viral envelope. Curcumin treatment induced the leakage of SRB from these liposomes and the addition of the influenza virus reduced the leakage, indicating that curcumin disrupts the integrity of the membranes of viral envelopes and of liposomes. When testing liposomes of various diameters, we detected higher levels of SRB leakage from the smaller-sized liposomes than from the larger liposomes. Interestingly, the curcumin concentration required to reduce plaque formation was lower for the influenza virus (approximately 100 nm in diameter) than for the pseudorabies virus (approximately 180 nm) and the vaccinia virus (roughly 335 × 200 × 200 nm). These data provide insights on the molecular antiviral mechanisms of curcumin and its potential use as an antiviral agent for enveloped viruses.

Wen, Hsiao-Wei; Ou, Jun-Lin; Chiou, Shyan-Song; Chen, Jo-Mei; Wong, Min-Liang; Hsu, Wei-Li

2013-01-01

452

Northern Light Special Edition: Computer Viruses  

NSDL National Science Digital Library

The latest special edition from Northern Light brings together a handy collection of resources on computer viruses, primarily news items and links to related sites. These are grouped in six sections, including current news, US government resources, online reference, anti-virus solutions, and virus writers & hackers. Each section begins with a link to related search returns from Northern Light. While this page is certainly not the end-all resource for virus information, it is a perfectly fine place to begin your search.

453

Feline Immunodeficiency Virus Orf-A Is Required for Virus Particle Formation and Virus Infectivity  

Microsoft Academic Search

The orf-A (orf-2) gene of feline immunodeficiency virus (FIV) is a small open reading frame predicted to encode a 77-amino-acid protein that contains putative domains similar to those of the ungulate lentiviral Tat protein. Orf-A is reported to be critical for efficient viral replication in vitro and in vivo. A series of FIV- pPPR-derived proviruses with in-frame deletions and point

Malou C. Gemeniano; Earl T. Sawai; Christian M. Leutenegger; Ellen E. Sparger

2003-01-01

454

A comparison of the antigens present on the surface of virus released artificially from chick cells infected with vaccinia virus, and cowpox virus and its white pock mutant  

PubMed Central

Antisera prepared against vaccinia and cowpox viruses were absorbed with purified suspensions of vaccinia virus, red cowpox and white cowpox viruses. They were then tested for their ability to neutralize the viruses, and to precipitate the virus soluble antigens. The results showed that some virus specific antigens were not virus surface components and that some components were present on the surface of all three viruses. However, certain components were detected on the surface of vaccinia virus but not on the surface of cowpox virus, and vice versa. Some evidence for the existence of a vaccinia-specific surface component was also obtained. Comparisons between results of cross-neutralization tests and immunodiffusion tests on the absorbed sera indicated that antibody to a number of antigens, including the classical LS, and the cowpox-specific d antigen play no part in the process of poxvirus neutralization. ImagesFig. AFig. BFig. CFig. DFig. EFig. FFig. G

Baxby, Derrick

1972-01-01

455

Interferon gene transfer by a hepatitis B virus vector efficiently suppresses wild-type virus infection  

PubMed Central

Hepatitis B viruses specifically target the liver, where they efficiently infect quiescent hepatocytes. Here we show that human and avian hepatitis B viruses can be converted into vectors for liver-directed gene transfer. These vectors allow hepatocyte-specific expression of a green fluorescent protein in vitro and in vivo. Moreover, when used to transduce a type I interferon gene, expression of interferon efficiently suppresses wild-type virus replication in the duck model of hepatitis B virus infection. These data suggest local cytokine production after hepatitis-B-virus-mediated gene transfer as a promising concept for the treatment of acquired liver diseases, including chronic hepatitis B.

Protzer, Ulrike; Nassal, Michael; Chiang, Pei-Wen; Kirschfink, Michael; Schaller, Heinz

1999-01-01

456

Interference between Cowpea Mosaic Virus and Cowpea Severe Mosaic Virus in a Cowpea Host Immune to Cowpea Mosaic Virus  

Microsoft Academic Search

SUMMARY Infection of a cowpea line by cowpea severe mosaic virus (CPSMV) was inhibited by cowpea mosaic virus (CPMV) even though the plants were immune to CPMV. The inhibition was dose-dependent and was complete if CPMV was added to the inoculum in a 50-fold excess over CPSMV. Isolated CPMV RNA inhibited infection by CPSMV or by isolated CPSMV RNA. CPMV

P. Sterk; C. P. De Jager

1987-01-01

457

Sendai Virus and Simian Virus 5 Block Activation of Interferon-Responsive Genes: Importance for Virus Pathogenesis  

Microsoft Academic Search

Sendai virus (SeV) is highly pathogenic for mice. In contrast, mice (including SCID mice) infected with simian virus 5 (SV5) showed no overt signs of disease. Evidence is presented that a major factor which prevented SV5 from productively infecting mice was its inability to circumvent the interferon (IFN) response in mice. Thus, in murine cells that produce and respond to

L. DIDCOCK; D. F. YOUNG; S. GOODBOURN; R. E. RANDALL

1999-01-01

458

Serological evidence of West Nile virus, Usutu virus and Sindbis virus infection of birds in the UK  

Microsoft Academic Search

The introduction and rapid dispersal of the African flavivirus West Nile virus (WNV) throughout North America, and the high fatality rate due to encephalitis in birds, horses, other wildlife species and humans, has attracted major attention worldwide. Usutu virus, another flavivirus, came to prominence in 2001, when it was identified as the agent responsible for a drop in the bird

Alan Buckley; Alistair Dawson; Stephen R. Moss; Shelley A. Hinsley; Paul E. Bellamy; Ernest A. Gould

2003-01-01

459

Viruses as an etiology of obesity.  

PubMed

Obesity is a serious chronic disease that has numerous etiologies. The prevalence of obesity has increased dramatically since about 1980 in the United States and worldwide in both developed and developing countries. This rapid spread is compatible with an infectious origin. This review discusses the 5 animal viruses and 3 human viruses that have been shown to cause obesity and examines the evidence to date for virus-induced obesity. The obesogenic animal viruses include canine distemper virus, Rous-associated virus type 7, Borna disease virus, scrapie agent, and SMAM-1. The first 4 viruses attack the central nervous system to produce obesity. SMAM-1, an avian adenovirus from India, acts directly on adipocytes and is the only animal virus that is associated with human obesity. The 3 human adenoviruses, adenovirus (Ad) 36, Ad-37, and Ad-5, that are associated with obesity also affect adipocytes directly. These viruses stimulate enzymes and transcription factors that cause accumulation of triglycerides and differentiation of preadipocytes into mature adipocytes. Ad-5 and Ad-37 have been shown to cause obesity in animals. Ad-36 has been studied the most and is the only human adenovirus to date that has been linked with human obesity. Ad-36 causes obesity in chickens, mice, rats, and monkeys and was present in 30% of obese humans and 11% of nonobese humans. In twins discordant for infection with Ad-36, the infected twins were heavier and fatter than their cotwins. The growing body of evidence demonstrating that viruses produce human obesity supports the concept that at least some of the worldwide epidemic of obesity in the past 25 years is due to viral infections. PMID:17908526

Atkinson, Richard L

2007-10-01

460

Cellular Proteins in Influenza Virus Particles  

PubMed Central

Virions are thought to contain all the essential proteins that govern virus egress from the host cell and initiation of replication in the target cell. It has been known for some time that influenza virions contain nine viral proteins; however, analyses of other enveloped viruses have revealed that proteins from the host cell can also be detected in virions. To address whether the same is true for influenza virus, we used two complementary mass spectrometry approaches to perform a comprehensive proteomic analysis of purified influenza virus particles. In addition to the aforementioned nine virus-encoded proteins, we detected the presence of 36 host-encoded proteins. These include both cytoplasmic and membrane-bound proteins that can be grouped into several functional categories, such as cytoskeletal proteins, annexins, glycolytic enzymes, and tetraspanins. Interestingly, a significant number of these have also been reported to be present in virions of other virus families. Protease treatment of virions combined with immunoblot analysis was used to verify the presence of the cellular protein and also to determine whether it is located in the core of the influenza virus particle. Immunogold labeling confirmed the presence of membrane-bound host proteins on the influenza virus envelope. The identification of cellular constituents of influenza virions has important implications for understanding the interactions of influenza virus with its host and brings us a step closer to defining the cellular requirements for influenza virus replication. While not all of the host proteins are necessarily incorporated specifically, those that are and are found to have an essential role represent novel targets for antiviral drugs and for attenuation of viruses for vaccine purposes.

Shaw, Megan L.; Stone, Kathryn L.; Colangelo, Christopher M.; Gulcicek, Erol E.; Palese, Peter

2008-01-01

461

Oncolytic virus therapy using genetically engineered herpes simplex viruses.  

PubMed

Genetically engineered, conditionally replicating herpes simplex viruses type 1 (HSV-1) are promising therapeutic agents for cancer. They can replicate in situ, spread, and exhibit oncolytic activity via a direct cytocidal effect. In addition, oncolytic HSV-1 can transfer and express foreign genes in host cells. The phase I clinical study with G207, a double-mutated HSV-1, in recurrent malignant glioma patients has shown that oncolytic HSV-1 can be safely administered into human brains. The therapeutic benefits of oncolytic HSV-1 depend on the extent of both intratumoral viral replication and induction of host antitumor immune responses. We develop new-generation oncolytic HSV-1 by enhancing these properties while retaining the safety features. G47delta was created from G207 by introducing another genetic mutation. Compared with G207, G47delta showed 1) better stimulation of human antitumor immune cells, 2) better growth properties leading to higher virus yields and increased cytopathic effect in vitro, 3) better antitumor efficacy in both immuno-competent and -incompetent animals, and 4) preserved safety in the brain of HSV-1-sensitive mice. Preparation is under way for a clinical trial using G47delta in progressive glioblastoma patients. G47delta is also suited as a backbone vector for expressing foreign molecules. Using bacterial artificial chromosome and two DNA recombinases, we have created an "armed" oncolytic HSV-1 generation system that allows insertion of transgene(s) into the genome of G47delta in a rapid and accurate manner. We found that expression of immunostimulatory molecules can significantly enhance the antitumor efficacy of G47delta. Based on these advances, we anticipate that oncolytic virus therapy using oncolytic HSV-1 will soon be established as an important modality of cancer treatment. PMID:17981691

Todo, Tomoki

2008-01-01

462

Virus Enrichment for Single Virus Infection by Using 3D Insulator Based Dielectrophoresis.  

PubMed

We developed an active virus filter (AVF) that enables virus enrichment for single virus infection, by using insulator-based dielectrophoresis (iDEP). A 3D-constricted flow channel design enabled the production of an iDEP force in the microfluidic chip. iDEP using a chip with multiple active virus filters (AVFs) was more accurate and faster than using a chip with a single AVF, and improved the efficiency of virus trapping. We utilized maskless photolithography to achieve the precise 3D gray-scale exposure required for fabrication of constricted flow channel. Influenza virus (A PR/8) was enriched by a negative DEP force when sinusoidal wave was applied to the electrodes within an amplitude range of 20 Vp-p and a frequency of 10 MHz. AVF-mediated virus enrichment can be repeated simply by turning the current ON or OFF. Furthermore, the negative AVF can inhibit virus adhesion onto the glass substrate. We then trapped and transported one of the enriched viruses by using optical tweezers. This microfluidic chip facilitated the effective transport of a single virus from AVFs towards the cell-containing chamber without crossing an electrode. We successfully transported the virus to the cell chamber (v?=?10 µm/s) and brought it infected with a selected single H292 cell. PMID:24918921

Masuda, Taisuke; Maruyama, Hisataka; Honda, Ayae; Arai, Fumihito

2014-01-01

463

The influenza virus hemagglutinin cytoplasmic tail is not essential for virus assembly or infectivity.  

PubMed Central

The influenza A virus hemagglutinin (HA) glycoprotein contains a cytoplasmic tail which consists of 10-11 amino acids, of which five residues re conserved in all subtypes of influenza A virus. As the cytoplasmic tail is not needed for intracellular transport to the plasma membrane, it has become virtually dogma that the role of the cytoplasmic tail is in forming protein-protein interactions necessary for creating an infectious budding virus. To investigate the role of the HA cytoplasmic tail in virus replication, reverse genetics was used to obtain an influenza virus that lacked an HA cytoplasmic tail. The rescued virus contained the HA of subtype A/Udorn/72 in a helper virus (subtype A/WSN/33) background. Biochemical analysis indicated that only the introduced tail- HA was incorporated into virions and these particles lacked a detectable fragment of the helper virus HA. The tail- HA rescued virus assembled and replicated almost as efficiently as virions containing wild-type HA, suggesting that the cytoplasmic tail is not essential for the virus assembly process. Nonetheless, a revertant virus was isolated, suggesting that possession of a cytoplasmic tail does confer an advantage. Images

Jin, H; Leser, G P; Lamb, R A

1994-01-01

464

An ssDNA virus infecting archaea: a new lineage of viruses with a membrane envelope.  

PubMed

Archaeal organisms are generally known as diverse extremophiles, but they play a crucial role also in moderate environments. So far, only about 50 archaeal viruses have been described in some detail. Despite this, unusual viral morphotypes within this group have been reported. Interestingly, all isolated archaeal viruses have a double-stranded DNA (dsDNA) genome. To further characterize the diversity of archaeal viruses, we screened highly saline water samples for archaea and their viruses. Here, we describe a new haloarchaeal virus, Halorubrum pleomorphic virus 1 (HRPV-1) that was isolated from a solar saltern and infects an indigenous host belonging to the genus Halorubrum. Infection does not cause cell lysis, but slightly retards growth of the host and results in high replication of the virus. The sequenced genome (7048 nucleotides) of HRPV-1 is single-stranded DNA (ssDNA), which makes HRPV-1 the first characterized archaeal virus that does not have a dsDNA genome. In spite of this, similarities to another archaeal virus were observed. Two major structural proteins were recognized in protein analyses, and by lipid analyses it was shown that the virion contains a membrane. Electron microscopy studies indicate that the enveloped virion is pleomorphic (approximately 44 x 55 nm). HRPV-1 virion may represent commonly used virion architecture, and it seems that structure-based virus lineages may be extended to non-icosahedral viruses. PMID:19298373

Pietilä, Maija K; Roine, Elina; Paulin, Lars; Kalkkinen, Nisse; Bamford, Dennis H

2009-04-01

465

Virus Enrichment for Single Virus Infection by Using 3D Insulator Based Dielectrophoresis  

PubMed Central

We developed an active virus filter (AVF) that enables virus enrichment for single virus infection, by using insulator-based dielectrophoresis (iDEP). A 3D-constricted flow channel design enabled the production of an iDEP force in the microfluidic chip. iDEP using a chip with multiple active virus filters (AVFs) was more accurate and faster than using a chip with a single AVF, and improved the efficiency of virus trapping. We utilized maskless photolithography to achieve the precise 3D gray-scale exposure required for fabrication of constricted flow channel. Influenza virus (A PR/8) was enriched by a negative DEP force when sinusoidal wave was applied to the electrodes within an amplitude range of 20 Vp-p and a frequency of 10 MHz. AVF-mediated virus enrichment can be repeated simply by turning the current ON or OFF. Furthermore, the negative AVF can inhibit virus adhesion onto the glass substrate. We then trapped and transported one of the enriched viruses by using optical tweezers. This microfluidic chip facilitated the effective transport of a single virus from AVFs towards the cell-containing chamber without crossing an electrode. We successfully transported the virus to the cell chamber (v?=?10 µm/s) and brought it infected with a selected single H292 cell.

Masuda, Taisuke; Maruyama, Hisataka; Honda, Ayae; Arai, Fumihito

2014-01-01

466

A Seven-Segmented Influenza A Virus Expressing the Influenza C Virus Glycoprotein HEF?  

PubMed Central

Influenza viruses are classified into three types: A, B, and C. The genomes of A- and B-type influenza viruses consist of eight RNA segments, whereas influenza C viruses only have seven RNAs. Both A and B influenza viruses contain two major surface glycoproteins: the hemagglutinin (HA) and the neuraminidase (NA). Influenza C viruses have only one major surface glycoprotein, HEF (hemagglutinin-esterase fusion). By using reverse genetics, we generated two seven-segmented chimeric influenza viruses. Each possesses six RNA segments from influenza virus A/Puerto Rico/8/34 (PB2, PB1, PA, NP, M, and NS); the seventh RNA segment encodes either the influenza virus C/Johannesburg/1/66 HEF full-length protein or a chimeric protein HEF-Ecto, which consists of the HEF ectodomain and the HA transmembrane and cytoplasmic regions. To facilitate packaging of the heterologous segment, both the HEF and HEF-Ecto coding regions are flanked by HA packaging sequences. When introduced as an eighth segment with the NA packaging sequences, both viruses are able to stably express a green fluorescent protein (GFP) gene, indicating a potential use for these viruses as vaccine vectors to carry foreign antigens. Finally, we show that incorporation of a GFP RNA segment enhances the growth of seven-segmented viruses, indicating that efficient influenza A viral RNA packaging requires the presence of eight RNA segments. These results support a selective mechanism of viral RNA recruitment to the budding site.

Gao, Qinshan; Brydon, Edward W. A.; Palese, Peter

2008-01-01

467

Mutations in the FPIV motif of Newcastle disease virus matrix protein attenuate virus replication and reduce virus budding.  

PubMed

The FPIV-like late domains identified in the matrix (M) proteins of parainfluenza virus 5 and mumps virus have been demonstrated to be critical for virus budding. In this study, we found that the same FPIV sequence motif is present in the N-terminus of the Newcastle disease virus (NDV) M protein. Mutagenesis experiments demonstrated that mutation of either phenylalanine (F) or proline (P) to alanine led to a more obvious decrease in viral virulence and replication and resulted in poor budding of the mutant viruses. Additionally, evidence for the involvement of cellular multivesicular body (MVB) proteins was obtained, since NDV production was inhibited upon expression of dominant-negative versions of the VPS4A-E228Q protein. Together, these results demonstrate that the FPIV motif, especially the residues F and P, within the NDV M protein, plays a critical role in NDV replication and budding, and this budding process likely involves the cellular MVB pathway. PMID:24477785

Duan, Zhiqiang; Hu, Zenglei; Zhu, Jie; Xu, Haixu; Chen, Jian; Liu, Huimou; Hu, Shunlin; Liu, Xiufan

2014-07-01

468

Hepatitis B virus taxonomy and hepatitis B virus genotypes  

PubMed Central

Hepatitis B virus (HBV) is a member of the hepadnavirus family. Hepadnaviruses can be found in both mammals (orthohepadnaviruses) and birds (avihepadnaviruses). The genetic variability of HBV is very high. There are eight genotypes of HBV and three clades of HBV isolates from apes that appear to be additional genotypes of HBV. Most genotypes are now divided into subgenotypes with distinct virological and epidemiological properties. In addition, recombination among HBV genotypes increases the variability of HBV. This review summarises current knowledge of the epidemiology of genetic variability in hepadnaviruses and, due to rapid progress in the field, updates several recent reviews on HBV genotypes and subgenotypes.

Schaefer, Stephan

2007-01-01

469

Construction of recombinant swinepox viruses and expression of the classical swine fever virus E2 protein.  

PubMed

To explore the swinepox virus (SPV) as a potential live vector for immunization, a vector was developed for the construction of a recombinant SPV carrying foreign genes. In this system, a foreign gene placed under the strong vaccinia virus promoter P(11) can be inserted into the viral thymidine kinase (TK) gene, and the recombinant virus can be isolated in a non-selective medium by the co-expression of E. coli lacZ gene. Compared with the wild type virus, the TK(-)recombinant SPV showed a modest level of attenuation in porcine cells while more attenuation was observed in monkey or human cells. Using this system, a recombinant virus expressing the E2 glycoprotein of classical swine fever virus (CSFV) was produced. Engineered with the gX signal sequence of the pseudorabies virus, and transmembrane domain of E2, the E2 protein was expressed as a dimeric form in the cytoplasm of the infected cells. PMID:11311343

Hahn, J; Park, S H; Song, J Y; An, S H; Ahn, B Y

2001-04-01

470

Expression of dengue virus structural proteins and nonstructural protein NS1 by a recombinant vaccinia virus.  

PubMed

A recombinant vaccinia virus containing cloned DNA sequences coding for the three structural proteins and nonstructural proteins NS1 and NS2a of dengue type 4 virus was constructed. Infection of CV-1 cells with this recombinant virus produced dengue virus structural proteins as well as the nonstructural protein NS1. These proteins were precipitated by specific antisera and exhibited the same molecular size and glycosylation patterns as authentic dengue virus proteins. Infection of cotton rats with the recombinant virus induced NS1 antibodies in 1 of 11 animals. However, an immune response to the PreM and E glycoproteins was not detected. A reduced level of gene expression was probably the reason for the limited serologic response to these dengue virus antigens. PMID:3316711

Zhao, B T; Prince, G; Horswood, R; Eckels, K; Summers, P; Chanock, R; Lai, C J

1987-12-01

471

Herpes Simplex Virus Type 1 Glycoprotein E Domains Involved in Virus Spread and Disease  

PubMed Central

Herpes simplex virus type 1 (HSV-1) glycoprotein E (gE) functions as an immunoglobulin G (IgG) Fc binding protein and is involved in virus spread. Previously we studied a gE mutant virus that was impaired for IgG Fc binding but intact for spread and another that was normal for both activities. To further evaluate the role of gE in spread, two additional mutant viruses were constructed by introducing linker insertion mutations either outside the IgG Fc binding domain at gE position 210 or within the IgG Fc binding domain at position 380. Both mutant viruses were impaired for spread in epidermal cells in vitro; however, the 380 mutant virus was significantly more impaired and was as defective as gE null virus. gE mutant viruses were inoculated into the murine flank to measure epidermal disease at the inoculation site, travel of virus to dorsal root ganglia, and spread of virus from ganglia back to skin to produce zosteriform lesions. Disease at the inoculation and zosteriform sites was reduced for both mutant viruses, but more so for the 380 mutant virus. Moreover, the 380 mutant virus was highly impaired in its ability to reach the ganglia, as demonstrated by virus culture and real-time quantitative PCR. The results indicate that the domain surrounding amino acid 380 is important for both spread and IgG Fc binding and suggest that this domain is a potential target for antiviral therapy or vaccines.

Saldanha, Charles E.; Lubinski, John; Martin, Claudia; Nagashunmugam, Thandavarayan; Wang, Liyang; van der Keyl, Harjeet; Tal-Singer, Ruth; Friedman, Harvey M.

2000-01-01

472

Genomic and antigenic characterization of Jos virus  

PubMed Central

Jos virus (JOSV), originally isolated in Jos, Nigeria in 1967, has remained unclassified despite cultivation in tissue culture, development of animal models of infection and implementation of seroprevalence surveys for infection. Here, we report genetic, ultrastructural and serological evidence that JOSV is an orthomyxovirus distinct from but phylogenetically related to viruses of the genus Thogotovirus.

Bussetti, Ana Valeria; Travassos da Rosa, Amelia; Savji, Nazir; Jain, Komal; Guzman, Hilda; Hutchison, Stephen; Popov, Vsevolod L.; Tesh, Robert B.; Lipkin, W. Ian

2012-01-01

473

Nanobodies®: new ammunition to battle viruses.  

PubMed

In 1989, a new type of antibody was identified, first in the sera of dromedaries and later also in all other species of the Camelidae family. These antibodies do not contain a light chain and also lack the first constant heavy domain. Today it is still unclear what the evolutionary advantage of such heavy chain-only antibodies could be. In sharp contrast, the broad applicability of the isolated variable antigen-binding domains (VHH) was rapidly recognized, especially for the development of therapeutic proteins, called Nanobodies(®). Here we summarize first some of the unique characteristics and features of VHHs. These will next be described in the context of different experimental therapeutic applications of Nanobodies against different viruses: HIV, Hepatitis B virus, influenza virus, Respiratory Syncytial virus, Rabies virus, FMDV, Poliovirus, Rotavirus, and PERVs. Next, the diagnostic application of VHHs (Vaccinia virus, Marburg virus and plant Tulip virus X), as well as an industrial application (lytic lactococcal 936 phage) will be described. In addition, the described data show that monovalent Nanobodies can possess unique characteristics not observed with conventional antibodies. The straightforward formatting into bivalent, multivalent, and/or multispecific Nanobodies allowed tailoring molecules for potency and cross-reactivity against viral targets with high sequence diversity. PMID:21939690

Vanlandschoot, Peter; Stortelers, Catelijne; Beirnaert, Els; Ibañez, Lorena Itatí; Schepens, Bert; Depla, Erik; Saelens, Xavier

2011-12-01

474

Human Immune Responses to Dengue Viruses.  

National Technical Information Service (NTIS)

Peripheral blood lymphocytes (PBL) from humans without antibodies to dengue 2 virus lysed dengue virus-infected Raji cells to a significantly greater degree than uninfected Raji cells. Addition of mouse anti-dengue antibody increased the lysis of dengue-i...

F. A. Ennis

1985-01-01

475

Virology: Independent virus development outside a host  

Microsoft Academic Search

Viruses are thought to be functionally inactive once they are outside and