Regulation of FeLV-945 by c-Myb binding and CBP recruitment to the LTR

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Finstad Samantha L

2004-09-01

Full Text Available Abstract Background Feline leukemia virus (FeLV induces degenerative, proliferative and malignant hematologic disorders in its natural host, the domestic cat. FeLV-945 is a viral variant identified as predominant in a cohort of naturally infected animals. FeLV-945 contains a unique sequence motif in the long terminal repeat (LTR comprised of a single copy of transcriptional enhancer followed by a 21-bp sequence triplicated in tandem. The LTR is precisely conserved among independent cases of multicentric lymphoma, myeloproliferative disease and anemia in animals from the cohort. The 21-bp triplication was previously shown to act as a transcriptional enhancer preferentially in hematopoietic cells and to confer a replicative advantage. The objective of the present study was to examine the molecular mechanism by which the 21-bp triplication exerts its influence and the selective advantage responsible for its precise conservation. Results Potential binding sites for the transcription factor, c-Myb, were identified across the repeat junctions of the 21-bp triplication. Such sites would not occur in the absence of the repeat; thus, a requirement for c-Myb binding to the repeat junctions of the triplication would exert a selective pressure to conserve its sequence precisely. Electrophoretic mobility shift assays demonstrated specific binding of c-Myb to the 21-bp triplication. Reporter gene assays showed that the triplication-containing LTR is responsive to c-Myb, and that responsiveness requires the presence of both c-Myb binding sites. Results further indicated that c-Myb in complex with the 21-bp triplication recruits the transcriptional co-activator, CBP, a regulator of normal hematopoiesis. FeLV-945 replication was shown to be positively regulated by CBP in a manner dependent on the presence of the 21-bp triplication. Conclusion Binding sites for c-Myb across the repeat junctions of the 21-bp triplication may account for its precise conservation in

An application of LTR design in fault detection

DEFF Research Database (Denmark)

Niemann, Hans Henrik

1998-01-01

The fault detection and isolation (FDI) problem is considered in this paper. The FDI problem is formulated as a filter design problem, where the faults in the system is estimated and the disturbance acting on the system is rejected. It turns out that the filter design problem can be considered...... as a standard Loop Transfer Recovery (LTR) design problem. As a consequence of the connection between LTR and FDI design, it is shown in an example how the LQG/LTR design method for full order and a proportional-integral observer can be applied with advantages in connection with FDI....

[Non-LTR retrotransposons: LINEs and SINEs in plant genome].

Science.gov (United States)

Cheng, Xu-Dong; Ling, Hong-Qing

2006-06-01

Retrotransposons are one of the drivers of genome evolution. They include LTR (long terminal repeat) retrotransposons, which widespread in Eukaryotagenomes, show structural similarity to retroviruses. Non-LTR retrotransposons were first discovered in animal genomes and then identified as ubiquitous components of nuclear genomes in many species across the plant kingdom. They constitute a large fraction of the repetitive DNA. Non-LTR retrotransposons are divided into LINEs (long interspersed nuclear elements) and SINEs (short interspersed nuclear elements). Transposition of non-LTR retrotransposons is rarely observed in plants indicating that most of them are inactive and/or under regulation of the host genome. Transposition is poorly understood, but experimental evidence from other genetic systems shows that LINEs are able to transpose autonomously while non-autonomous SINEs depend on the reverse transcription machinery of other retrotransposons. Phylogenic analysis shows LINEs are probably the most ancient class of retrotransposons in plant genomes, while the origin of SINEs is unknown. This review sums up the above data and wants to show readers a clear picture of non-LTR retrotransposons.

A Theory of LTR Junk-food Consumption

OpenAIRE

Levy, Amnon

2003-01-01

LTR junk-food consumption balances the marginal satisfaction with the marginal deterioration of health. An LTR person discounts the instantaneous marginal satisfaction from junk-food consumption by its implications for his survival probability. His change rate of health evaluation is increased (decreased) by junk-food consumption when health is better (worse) than a critical level. The moderating direct effects of age and relative price on junk-food consumption may be amplified, or dimmed, by...

Convergent evolution of ribonuclease h in LTR retrotransposons and retroviruses.

Science.gov (United States)

Ustyantsev, Kirill; Novikova, Olga; Blinov, Alexander; Smyshlyaev, Georgy

2015-05-01

Ty3/Gypsy long terminals repeat (LTR) retrotransposons are structurally and phylogenetically close to retroviruses. Two notable structural differences between these groups of genetic elements are 1) the presence in retroviruses of an additional envelope gene, env, which mediates infection, and 2) a specific dual ribonuclease H (RNH) domain encoded by the retroviral pol gene. However, similar to retroviruses, many Ty3/Gypsy LTR retrotransposons harbor additional env-like genes, promoting concepts of the infective mode of these retrotransposons. Here, we provide a further line of evidence of similarity between retroviruses and some Ty3/Gypsy LTR retrotransposons. We identify that, together with their additional genes, plant Ty3/Gypsy LTR retrotransposons of the Tat group have a second RNH, as do retroviruses. Most importantly, we show that the resulting dual RNHs of Tat LTR retrotransposons and retroviruses emerged independently, providing strong evidence for their convergent evolution. The convergent resemblance of Tat LTR retrotransposons and retroviruses may indicate similar selection pressures acting on these diverse groups of elements and reveal potential evolutionary constraints on their structure. We speculate that dual RNH is required to accelerate retrotransposon evolution through increased rates of strand transfer events and subsequent recombination events. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

LTR retrotransposon landscape in Medicago truncatula: more rapid removal than in rice

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Liu Jin-Song

2008-08-01

Full Text Available Abstract Background Long terminal repeat retrotransposons (LTR elements are ubiquitous Eukaryotic TEs that transpose through RNA intermediates. Accounting for significant proportion of many plant genomes, LTR elements have been well established as one of the major forces underlying the evolution of plant genome size, structure and function. The accessibility of more than 40% of genomic sequences of the model legume Medicago truncatula (Mt has made the comprehensive study of its LTR elements possible. Results We use a newly developed tool LTR_FINDER to identify LTR retrotransposons in the Mt genome and detect 526 full-length elements as well as a great number of copies related to them. These elements constitute about 9.6% of currently available genomic sequences. They are classified into 85 families of which 64 are reported for the first time. The majority of the LTR retrotransposons belong to either Copia or Gypsy superfamily and the others are categorized as TRIMs or LARDs by their length. We find that the copy-number of Copia-like families is 3 times more than that of Gypsy-like ones but the latter contribute more to the genome. The analysis of PBS and protein-coding domain structure of the LTR families reveals that they tend to use only 4–5 types of tRNAs and many families have quite conservative ORFs besides known TE domains. For several important families, we describe in detail their abundance, conservation, insertion time and structure. We investigate the amplification-deletion pattern of the elements and find that the detectable full-length elements are relatively young and most of them were inserted within the last 0.52 MY. We also estimate that more than ten million bp of the Mt genomic sequences have been removed by the deletion of LTR elements and the removal of the full-length structures in Mt has been more rapid than in rice. Conclusion This report is the first comprehensive description and analysis of LTR retrotransposons in the

Rotavirus 2/6 Viruslike Particles Administered Intranasally with Cholera Toxin, Escherichia coli Heat-Labile Toxin (LT), and LT-R192G Induce Protection from Rotavirus Challenge

OpenAIRE

O’Neal, Christine M.; Clements, John D.; Estes, Mary K.; Conner, Margaret E.

1998-01-01

We have shown that rotavirus 2/6 viruslike particles composed of proteins VP2 and VP6 (2/6-VLPs) administered to mice intranasally with cholera toxin (CT) induced protection from rotavirus challenge, as measured by virus shedding. Since it is unclear if CT will be approved for human use, we evaluated the adjuvanticity of Escherichia coli heat-labile toxin (LT) and LT-R192G. Mice were inoculated intranasally with 10 μg of 2/6-VLPs combined with CT, LT, or LT-R192G. All three adjuvants induced ...

Akv murine leukemia virus enhances bone tumorigenesis in hMT-c-fos-LTR transgenic mice

DEFF Research Database (Denmark)

Schmidt, Jörg; Krump-Konvalinkova, Vera; Luz, Arne

1995-01-01

hMt-c-fos-LTR transgenic mice (U. Rüther, D. Komitowski, F. R. Schubert, and E. F. Wagner. Oncogene 4, 861–865, 1989) developed bone sarcomas in 20% (3/15) of females at 448 ± 25 days and in 8% (1/12) of males at 523 days. After infection of newborns with Akv, an infectious retrovirus derived from...

An Analysis Of Pole/zero Cancellation In LTR-based Feedback Design

DEFF Research Database (Denmark)

Niemann, Hans Henrik; Jannerup, Ole Erik

1990-01-01

The pole/zero cancellation in LTR-based feedback design will be analyzed for both full-order as well as minimal-order observers. The asymptotic behaviour of the sensitivity function from the LTR-procedure are given in explicit expressions in the case when a zero is not cancelled by an equivalent...... pole. It will be shown that the non-minimum phase case is included as a special case. The results are not based on any specific LTR-method....

Long Terminal Repeat Circular DNA as Markers of Active Viral Replication of Human T Lymphotropic Virus-1 in Vivo

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James M Fox

2016-03-01

Full Text Available Clonal expansion of human T-lymphotropic virus type-1 (HTLV-1 infected cells in vivo is well documented. Unlike human immunodeficiency virus type 1 (HIV-1, HTLV-1 plasma RNA is sparse. The contribution of the “mitotic” spread of HTLV-1 compared with infectious spread of the virus to HTLV-1 viral burden in established infection is uncertain. Since extrachromosomal long terminal repeat (LTR DNA circles are indicators of viral replication in HIV-1 carriers with undetectable plasma HIV RNA, we hypothesised that HTLV-1 LTR circles could indicate reverse transcriptase (RT usage and infectious activity. 1LTR and 2LTR DNA circles were measured in HTLV-1 cell lines and peripheral blood mononuclear cells (PBMC of asymptomatic carriers (ACs and patients with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP or adult T cell leukaemia/lymphoma (ATLL. 1LTR DNA circles were detected in 14/20 patients at a mean of 1.38/100 PBMC but did not differentiate disease status nor correlate with HTLV-1 DNA copies. 2LTR DNA circles were detected in 30/31 patients and at higher concentrations in patients with HTLV-1-associated diseases, independent of HTLV-1 DNA load. In an incident case the 2LTR DNA circle concentration increased 2.1 fold at the onset of HAM/TSP compared to baseline. Detectable and fluctuating levels of HTLV-1 DNA circles in patients indicate viral RT usage and virus replication. Our results indicate HTLV-1 viral replication capacity is maintained in chronic infection and may be associated with disease onset.

Characterization of Equine Infectious Anemia Virus Long Terminal Repeat Quasispecies In Vitro and In Vivo.

Science.gov (United States)

Wang, Xue-Feng; Liu, Qiang; Wang, Yu-Hong; Wang, Shuai; Chen, Jie; Lin, Yue-Zhi; Ma, Jian; Zhou, Jian-Hua; Wang, Xiaojun

2018-04-15

The equine infectious anemia virus (EIAV) attenuated vaccine was developed by long-term passaging of a field-isolated virulent strain in cross-species hosts, followed by successive cultivation in cells in vitro To explore the molecular mechanism underlying the evolution of the EIAV attenuated vaccine, a systematic study focusing on long-terminal-repeat (LTR) variation in numerous virus strains ranging from virulent EIAV to attenuated EIAV was performed over time both in vitro and in vivo Two hypervariable regions were identified within the U3 region in the enhancer region (EHR) and the negative regulatory element (NRE) and within the R region in the transcription start site (TSS) and the Tat-activating region (TAR). Among these sites, variation in the U3 region resulted in the formation of additional transcription factor binding sites; this variation of the in vitro -adapted strains was consistent with the loss of pathogenicity. Notably, the same LTR variation pattern was observed both in vitro and in vivo Generally, the LTR variation in both the attenuated virus and the virulent strain fluctuated over time in vivo Interestingly, the attenuated-virus-specific LTR variation was also detected in horses infected with the virulent strain, supporting the hypothesis that the evolution of an attenuated virus might have involved branching from EIAV quasispecies. This hypothesis was verified by phylogenetic analysis. The present systematic study examining the molecular evolution of attenuated EIAV from EIAV quasispecies may provide an informative model reflecting the evolution of similar lentiviruses. IMPORTANCE The attenuated EIAV vaccine was the first lentiviral vaccine used to successfully control for equine infectious anemia in China. This vaccine provides an important reference for studying the relationship between EIAV gene variation and changes in biological characteristics. Importantly, the vaccine provides a model for the investigation of lentiviral quasispecies

Intracellular high mobility group B1 protein (HMGB1) represses HIV-1 LTR-directed transcription in a promoter- and cell-specific manner

International Nuclear Information System (INIS)

Naghavi, Mojgan H.; Nowak, Piotr; Andersson, Jan; Soennerborg, Anders; Yang Huan; Tracey, Kevin J.; Vahlne, Anders

2003-01-01

We investigated whether the high mobility group B 1 (HMGB1), an abundant nuclear protein in all mammalian cells, affects HIV-1 transcription. Intracellular expression of human HMGB1 repressed HIV-1 gene expression in epithelial cells. This inhibitory effect of HMGB1 was caused by repression of long terminal repeat (LTR)-mediated transcription. Other viral promoters/enhancers, including simian virus 40 or cytomegalovirus, were not inhibited by HMGB1. In addition, HMGB1 inhibition of HIV-1 subtype C expression was dependent on the number of NFκB sites in the LTR region. The inhibitory effect of HMGB1 on viral gene expression observed in HeLa cells was confirmed by an upregulation of viral replication in the presence of antisense HMGB1 in monocytic cells. In contrast to what was found in HeLa cells and monocytic cells, endogenous HMGB1 expression did not affect HIV-1 replication in unstimulated Jurkat cells. Thus, intracellular HMGB1 affects HIV-1 LTR-directed transcription in a promoter- and cell-specific manner

Nuclear Matrix protein SMAR1 represses HIV-1 LTR mediated transcription through chromatin remodeling

International Nuclear Information System (INIS)

Sreenath, Kadreppa; Pavithra, Lakshminarasimhan; Singh, Sandeep; Sinha, Surajit; Dash, Prasanta K.; Siddappa, Nagadenahalli B.; Ranga, Udaykumar; Mitra, Debashis; Chattopadhyay, Samit

2010-01-01

Nuclear Matrix and MARs have been implicated in the transcriptional regulation of host as well as viral genes but their precise role in HIV-1 transcription remains unclear. Here, we show that > 98% of HIV sequences contain consensus MAR element in their promoter. We show that SMAR1 binds to the LTR MAR and reinforces transcriptional silencing by tethering the LTR MAR to nuclear matrix. SMAR1 associated HDAC1-mSin3 corepressor complex is dislodged from the LTR upon cellular activation by PMA/TNFα leading to an increase in the acetylation and a reduction in the trimethylation of histones, associated with the recruitment of RNA Polymerase II on the LTR. Overexpression of SMAR1 lead to reduction in LTR mediated transcription, both in a Tat dependent and independent manner, resulting in a decreased virion production. These results demonstrate the role of SMAR1 in regulating viral transcription by alternative compartmentalization of LTR between the nuclear matrix and chromatin.

Rotavirus 2/6 Viruslike Particles Administered Intranasally with Cholera Toxin, Escherichia coli Heat-Labile Toxin (LT), and LT-R192G Induce Protection from Rotavirus Challenge

Science.gov (United States)

O’Neal, Christine M.; Clements, John D.; Estes, Mary K.; Conner, Margaret E.

1998-01-01

We have shown that rotavirus 2/6 viruslike particles composed of proteins VP2 and VP6 (2/6-VLPs) administered to mice intranasally with cholera toxin (CT) induced protection from rotavirus challenge, as measured by virus shedding. Since it is unclear if CT will be approved for human use, we evaluated the adjuvanticity of Escherichia coli heat-labile toxin (LT) and LT-R192G. Mice were inoculated intranasally with 10 μg of 2/6-VLPs combined with CT, LT, or LT-R192G. All three adjuvants induced equivalent geometric mean titers of rotavirus-specific serum antibody and intestinal immunoglobulin G (IgG). Mice inoculated with 2/6-VLPs with LT produced significantly higher titers of intestinal IgA than mice given CT as the adjuvant. All mice inoculated with 2/6-VLPs mixed with LT and LT-R192G were totally protected (100%) from rotavirus challenge, while mice inoculated with 2/6-VLPs mixed with CT showed a mean 91% protection from challenge. The availability of a safe, effective mucosal adjuvant such as LT-R192G will increase the practicality of administering recombinant vaccines mucosally. PMID:9525668

Ex vivo response to histone deacetylase (HDAC inhibitors of the HIV long terminal repeat (LTR derived from HIV-infected patients on antiretroviral therapy.

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Hao K Lu

Full Text Available Histone deacetylase inhibitors (HDACi can induce human immunodeficiency virus (HIV transcription from the HIV long terminal repeat (LTR. However, ex vivo and in vivo responses to HDACi are variable and the activity of HDACi in cells other than T-cells have not been well characterised. Here, we developed a novel assay to determine the activity of HDACi on patient-derived HIV LTRs in different cell types. HIV LTRs from integrated virus were amplified using triple-nested Alu-PCR from total memory CD4+ T-cells (CD45RO+ isolated from HIV-infected patients prior to and following suppressive antiretroviral therapy. NL4-3 or patient-derived HIV LTRs were cloned into the chromatin forming episomal vector pCEP4, and the effect of HDACi investigated in the astrocyte and epithelial cell lines SVG and HeLa, respectively. There were no significant differences in the sequence of the HIV LTRs isolated from CD4+ T-cells prior to and after 18 months of combination antiretroviral therapy (cART. We found that in both cell lines, the HDACi panobinostat, trichostatin A, vorinostat and entinostat activated patient-derived HIV LTRs to similar levels seen with NL4-3 and all patient derived isolates had similar sensitivity to maximum HDACi stimulation. We observed a marked difference in the maximum fold induction of luciferase by HDACi in HeLa and SVG, suggesting that the effect of HDACi may be influenced by the cellular environment. Finally, we observed significant synergy in activation of the LTR with vorinostat and the viral protein Tat. Together, our results suggest that the LTR sequence of integrated virus is not a major determinant of a functional response to an HDACi.

Inability of Kaplan radiation leukemia virus to replicate on mouse fibroblasts is conferred by its long terminal repeat

International Nuclear Information System (INIS)

Rassart, E.; Paquette, Y.; Jolicoeur, P.

1988-01-01

The molecularly cloned infectious Kaplan radiation leukemia virus has previously been shown to be unable to replicate on mouse fibroblasts. To map the viral sequences responsible for this, we constructed chimeric viral DNA genomes in vitro with parental cloned infectious viral DNAs from the nonfibrotropic (F-) BL/VL3 V-13 radiation leukemia virus and the fibrotropic (F+) endogenous BALB/c or Moloney murine leukemia viruses (MuLV). Infectious chimeric MuLVs, recovered after transfection of Ti-6 lymphocytes with these recombinant DNAs, were tested for capacity to replicate on mouse fibroblasts in vitro. We found that chimeric MuLVs harboring the long terminal repeat (LTR) of a fibrotropic MuLV replicated well on mouse fibroblasts. Conversely, chimeric MuLVs harboring the LTR of a nonfibrotropic MuLV were restricted on mouse fibroblasts. These results indicate that the LTR of BL/VL3 radiation leukemia virus harbors the primary determinant responsible for its inability to replicate on mouse fibroblasts in vitro. Our results also show that the primary determinant allowing F+ MuLVs (endogenous BALB/c and Moloney MuLVs) to replicate on mouse fibroblasts in vitro resides within the LTR

Accurate episomal HIV 2-LTR circles quantification using optimized DNA isolation and droplet digital PCR.

Science.gov (United States)

Malatinkova, Eva; Kiselinova, Maja; Bonczkowski, Pawel; Trypsteen, Wim; Messiaen, Peter; Vermeire, Jolien; Verhasselt, Bruno; Vervisch, Karen; Vandekerckhove, Linos; De Spiegelaere, Ward

2014-01-01

In HIV-infected patients on combination antiretroviral therapy (cART), the detection of episomal HIV 2-LTR circles is a potential marker for ongoing viral replication. Quantification of 2-LTR circles is based on quantitative PCR or more recently on digital PCR assessment, but is hampered due to its low abundance. Sample pre-PCR processing is a critical step for 2-LTR circles quantification, which has not yet been sufficiently evaluated in patient derived samples. We compared two sample processing procedures to more accurately quantify 2-LTR circles using droplet digital PCR (ddPCR). Episomal HIV 2-LTR circles were either isolated by genomic DNA isolation or by a modified plasmid DNA isolation, to separate the small episomal circular DNA from chromosomal DNA. This was performed in a dilution series of HIV-infected cells and HIV-1 infected patient derived samples (n=59). Samples for the plasmid DNA isolation method were spiked with an internal control plasmid. Genomic DNA isolation enables robust 2-LTR circles quantification. However, in the lower ranges of detection, PCR inhibition caused by high genomic DNA load substantially limits the amount of sample input and this impacts sensitivity and accuracy. Moreover, total genomic DNA isolation resulted in a lower recovery of 2-LTR templates per isolate, further reducing its sensitivity. The modified plasmid DNA isolation with a spiked reference for normalization was more accurate in these low ranges compared to genomic DNA isolation. A linear correlation of both methods was observed in the dilution series (R2=0.974) and in the patient derived samples with 2-LTR numbers above 10 copies per million peripheral blood mononuclear cells (PBMCs), (R2=0.671). Furthermore, Bland-Altman analysis revealed an average agreement between the methods within the 27 samples in which 2-LTR circles were detectable with both methods (bias: 0.3875±1.2657 log10). 2-LTR circles quantification in HIV-infected patients proved to be more

Analysis of plant LTR-retrotransposons at the fine-scale family level reveals individual molecular patterns

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Domingues Douglas S

2012-04-01

Full Text Available Abstract Background Sugarcane is an important crop worldwide for sugar production and increasingly, as a renewable energy source. Modern cultivars have polyploid, large complex genomes, with highly unequal contributions from ancestral genomes. Long Terminal Repeat retrotransposons (LTR-RTs are the single largest components of most plant genomes and can substantially impact the genome in many ways. It is therefore crucial to understand their contribution to the genome and transcriptome, however a detailed study of LTR-RTs in sugarcane has not been previously carried out. Results Sixty complete LTR-RT elements were classified into 35 families within four Copia and three Gypsy lineages. Structurally, within lineages elements were similar, between lineages there were large size differences. FISH analysis resulted in the expected pattern of Gypsy/heterochromatin, Copia/euchromatin, but in two lineages there was localized clustering on some chromosomes. Analysis of related ESTs and RT-PCR showed transcriptional variation between tissues and families. Four distinct patterns were observed in sRNA mapping, the most unusual of which was that of Ale1, with very large numbers of 24nt sRNAs in the coding region. The results presented support the conclusion that distinct small RNA-regulated pathways in sugarcane target the lineages of LTR-RT elements. Conclusions Individual LTR-RT sugarcane families have distinct structures, and transcriptional and regulatory signatures. Our results indicate that in sugarcane individual LTR-RT families have distinct behaviors and can potentially impact the genome in diverse ways. For instance, these transposable elements may affect nearby genes by generating a diverse set of small RNA's that trigger gene silencing mechanisms. There is also some evidence that ancestral genomes contribute significantly different element numbers from particular LTR-RT lineages to the modern sugarcane cultivar genome.

Evolutionary genomics revealed interkingdom distribution of Tcn1-like chromodomain-containing Gypsy LTR retrotransposons among fungi and plants

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Blinov Alexander

2010-04-01

Full Text Available Abstract Background Chromodomain-containing Gypsy LTR retrotransposons or chromoviruses are widely distributed among eukaryotes and have been found in plants, fungi and vertebrates. The previous comprehensive survey of chromoviruses from mosses (Bryophyta suggested that genomes of non-seed plants contain the clade which is closely related to the retrotransposons from fungi. The origin, distribution and evolutionary history of this clade remained unclear mainly due to the absence of information concerning the diversity and distribution of LTR retrotransposons in other groups of non-seed plants as well as in fungal genomes. Results In present study we preformed in silico analysis of chromodomain-containing LTR retrotransposons in 25 diverse fungi and a number of plant species including spikemoss Selaginella moellendorffii (Lycopodiophyta coupled with an experimental survey of chromodomain-containing Gypsy LTR retrotransposons from diverse non-seed vascular plants (lycophytes, ferns, and horsetails. Our mining of Gypsy LTR retrotransposons in genomic sequences allowed identification of numerous families which have not been described previously in fungi. Two new well-supported clades, Galahad and Mordred, as well as several other previously unknown lineages of chromodomain-containing Gypsy LTR retrotransposons were described based on the results of PCR-mediated survey of LTR retrotransposon fragments from ferns, horsetails and lycophytes. It appeared that one of the clades, namely Tcn1 clade, was present in basidiomycetes and non-seed plants including mosses (Bryophyta and lycophytes (genus Selaginella. Conclusions The interkingdom distribution is not typical for chromodomain-containing LTR retrotransposons clades which are usually very specific for a particular taxonomic group. Tcn1-like LTR retrotransposons from fungi and non-seed plants demonstrated high similarity to each other which can be explained by strong selective constraints and the

Low levels of LTR retrotransposon deletion by ectopic recombination in the gigantic genomes of salamanders.

Science.gov (United States)

Frahry, Matthew Blake; Sun, Cheng; Chong, Rebecca A; Mueller, Rachel Lockridge

2015-02-01

Across the tree of life, species vary dramatically in nuclear genome size. Mutations that add or remove sequences from genomes-insertions or deletions, or indels-are the ultimate source of this variation. Differences in the tempo and mode of insertion and deletion across taxa have been proposed to contribute to evolutionary diversity in genome size. Among vertebrates, most of the largest genomes are found within the salamanders, an amphibian clade with genome sizes ranging from ~14 to ~120 Gb. Salamander genomes have been shown to experience slower rates of DNA loss through small (i.e., genomes. However, no studies have addressed DNA loss from salamander genomes resulting from larger deletions. Here, we focus on one type of large deletion-ectopic-recombination-mediated removal of LTR retrotransposon sequences. In ectopic recombination, double-strand breaks are repaired using a "wrong" (i.e., ectopic, or non-allelic) template sequence-typically another locus of similar sequence. When breaks occur within the LTR portions of LTR retrotransposons, ectopic-recombination-mediated repair can produce deletions that remove the internal transposon sequence and the equivalent of one of the two LTR sequences. These deletions leave a signature in the genome-a solo LTR sequence. We compared levels of solo LTRs in the genomes of four salamander species with levels present in five vertebrates with smaller genomes. Our results demonstrate that salamanders have low levels of solo LTRs, suggesting that ectopic-recombination-mediated deletion of LTR retrotransposons occurs more slowly than in other vertebrates with smaller genomes.

Insertion of a solo LTR retrotransposon associates with spur mutations in 'Red Delicious' apple (Malus × domestica).

Science.gov (United States)

Han, Mengxue; Sun, Qibao; Zhou, Junyong; Qiu, Huarong; Guo, Jing; Lu, Lijuan; Mu, Wenlei; Sun, Jun

2017-09-01

Insertion of a solo LTR, which possesses strong bidirectional, stem-specific promoter activities, is associated with the evolution of a dwarfing apple spur mutation. Spur mutations in apple scions revolutionized global apple production. Since long terminal repeat (LTR) retrotransposons are tightly related to natural mutations, inter-retrotransposon-amplified polymorphism technique and genome walking were used to find sequences in the apple genome based on these LTRs. In 'Red Delicious' spur mutants, a novel, 2190-bp insertion was identified as a spur-specific, solo LTR (sLTR) located at the 1038th nucleotide of another sLTR, which was 1536 bp in length. This insertion-within-an-insertion was localized within a preexisting Gypsy-50 retrotransposon at position 3,762,767 on chromosome 4. The analysis of transcriptional activity of the two sLTRs (the 2190- and 1536-bp inserts) indicated that the 2190-bp sLTR is a promoter, capable of bidirectional transcription. GUS expression in the 2190-bp-sense and 2190-bp-antisense transgenic lines was prominent in stems. In contrast, no promoter activity from either the sense or the antisense strand of the 1536-bp sLTR was detected. From ~150 kb of DNA on each side of the 2190 bp, sLTR insertion site, corresponding to 300 kb of the 'Golden Delicious' genome, 23 genes were predicted. Ten genes had predicted functions that could affect shoot development. This first report, of a sLTR insertion associated with the evolution of apple spur mutation, will facilitate apple breeding, cloning of spur-related genes, and discovery of mechanisms behind dwarf habit.

Human immunodeficiency virus long terminal repeat responds to T-cell activation signals

International Nuclear Information System (INIS)

Tong-Starksen, S.E.; Luciw, P.A.; Peterlin, B.M.

1987-01-01

Human immunodeficiency virus (HIV), the causative agent of AIDS, infects and kills lymphoid cells bearing the CD4 antigen. In an infected cell, a number of cellular as well as HIV-encoded gene products determine the levels of viral gene expression and HIV replication. Efficient HIV replication occurs in activated T cells. Utilizing transient expression assays, the authors show that gene expression directed by the HIV long terminal repeat (LTR) increases in response to T-cell activation signals. The effects of T-cell activation and of the HIV-encoded trans-activator (TAT) are multiplicative. Analysis of mutations and deletions in the HIV LTR reveals that the region responding to T-cell activation signals is located at positions -105 to -80. These sequences are composed of two direct repeats, which are homologous to the core transcriptional enhancer elements in the simian virus 40 genome. The studies reveal that these elements function as the HIV enhancer. By acting directly on the HIV LTR, T-cell activation may play an important role in HIV gene expression and in the activation of latent HIV

Full Length Research Paper LTR-retrotransposons-based molecular ...

African Journals Online (AJOL)

LTR-retrotransposons possess unique properties that make them appropriate for investigating relationships between closely related species and populations. The aim of the current study was to employ Ty1-copia group retrotransposons as molecular markers in cultivated Egyptian cottons, G. barbadense L. Restriction site ...

Regulatory elements involved in tax-mediated transactivation of the HTLV-I LTR.

Science.gov (United States)

Seeler, J S; Muchardt, C; Podar, M; Gaynor, R B

1993-10-01

HTLV-I is the etiologic agent of adult T-cell leukemia. In this study, we investigated the regulatory elements and cellular transcription factors which function in modulating HTLV-I gene expression in response to the viral transactivator protein, tax. Transfection experiments into Jurkat cells of a variety of site-directed mutants in the HTLV-1 LTR indicated that each of the three motifs A, B, and C within the 21-bp repeats, the binding sites for the Ets family of proteins, and the TATA box all influenced the degree of tax-mediated activation. Tax is also able to activate gene expression of other viral and cellular promoters. Tax activation of the IL-2 receptor and the HIV-1 LTR is mediated through NF-kappa B motifs. Interestingly, sequences in the 21-bp repeat B and C motifs contain significant homology with NF-kappa B regulatory elements. We demonstrated that an NF-kappa B binding protein, PRDII-BF1, but not the rel protein, bound to the B and C motifs in the 21-bp repeat. PRDII-BF1 was also able to stimulate activation of HTLV-I gene expression by tax. The role of the Ets proteins on modulating tax activation was also studied. Ets 1 but not Ets 2 was capable of increasing the degree of tax activation of the HTLV-I LTR. These results suggest that tax activates gene expression by either direct or indirect interaction with several cellular transcription factors that bind to the HTLV-I LTR.

A novel function for spumaretrovirus integrase: an early requirement for integrase-mediated cleavage of 2 LTR circles

Directory of Open Access Journals (Sweden)

Mouscadet Jean-François

2005-05-01

Full Text Available Abstract Retroviral integration is central to viral persistence and pathogenesis, cancer as well as host genome evolution. However, it is unclear why integration appears essential for retrovirus production, especially given the abundance and transcriptional potential of non-integrated viral genomes. The involvement of retroviral endonuclease, also called integrase (IN, in replication steps apart from integration has been proposed, but is usually considered to be accessory. We observe here that integration of a retrovirus from the spumavirus family depends mainly on the quantity of viral DNA produced. Moreover, we found that IN directly participates to linear DNA production from 2-LTR circles by specifically cleaving the conserved palindromic sequence found at LTR-LTR junctions. These results challenge the prevailing view that integrase essential function is to catalyze retroviral DNA integration. Integrase activity upstream of this step, by controlling linear DNA production, is sufficient to explain the absolute requirement for this enzyme. The novel role of IN over 2-LTR circle junctions accounts for the pleiotropic effects observed in cells infected with IN mutants. It may explain why 1 2-LTR circles accumulate in vivo in mutants carrying a defective IN while their linear and integrated DNA pools decrease; 2 why both LTRs are processed in a concerted manner. It also resolves the original puzzle concerning the integration of spumaretroviruses. More generally, it suggests to reassess 2-LTR circles as functional intermediates in the retrovirus cycle and to reconsider the idea that formation of the integrated provirus is an essential step of retrovirus production.

Prophylactic Administration of Bacterially Derived Immunomodulators Improves the Outcome of Influenza Virus Infection in a Murine Model▿

Science.gov (United States)

Norton, Elizabeth B.; Clements, John D.; Voss, Thomas G.; Cárdenas-Freytag, Lucia

2010-01-01

Prophylactic or therapeutic immunomodulation is an antigen-independent strategy that induces nonspecific immune system activation, thereby enhancing host defense to disease. In this study, we investigated the effect of prophylactic immunomodulation on the outcome of influenza virus infection using three bacterially derived immune-enhancing agents known for promoting distinct immunological profiles. BALB/c mice were treated nasally with either cholera toxin (CT), a mutant form of the CT-related Escherichia coli heat-labile enterotoxin designated LT(R192G), or CpG oligodeoxynucleotide. Mice were subsequently challenged with a lethal dose of influenza A/PR/8/34 virus 24 h after the last immunomodulation treatment and either monitored for survival or sacrificed postchallenge for viral and immunological analysis. Treatment with the three immunomodulators prevented or delayed mortality and weight loss, but only CT and LT(R192G) significantly reduced initial lung viral loads as measured by plaque assay. Analysis performed 4 days postinfection indicated that prophylactic treatments with CT, LT(R192G), or CpG resulted in significantly increased numbers of CD4 T cells, B cells, and dendritic cells and altered costimulatory marker expression in the airways of infected mice, coinciding with reduced expression of pulmonary chemokines and the appearance of inducible bronchus-associated lymphoid tissue-like structures in the lungs. Collectively, these results suggest that, despite different immunomodulatory mechanisms, CT, LT(R192G), and CpG induce an initial inflammatory process and enhance the immune response to primary influenza virus challenge while preventing potentially damaging chemokine expression. These studies provide insight into the immunological parameters and immune modulation strategies that have the potential to enhance the nonspecific host response to influenza virus infection. PMID:20053748

Deletion of the LTR enhancer/promoter has no impact on the integration profile of MLV vectors in human hematopoietic progenitors.

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Arianna Moiani

Full Text Available Moloney murine leukemia virus (MLV-derived gamma-retroviral vectors integrate preferentially near transcriptional regulatory regions in the human genome, and are associated with a significant risk of insertional gene deregulation. Self-inactivating (SIN vectors carry a deletion of the U3 enhancer and promoter in the long terminal repeat (LTR, and show reduced genotoxicity in pre-clinical assays. We report a high-definition analysis of the integration preferences of a SIN MLV vector compared to a wild-type-LTR MLV vector in the genome of CD34(+ human hematopoietic stem/progenitor cells (HSPCs. We sequenced 13,011 unique SIN-MLV integration sites and compared them to 32,574 previously generated MLV sites in human HSPCs. The SIN-MLV vector recapitulates the integration pattern observed for MLV, with the characteristic clustering of integrations around enhancer and promoter regions associated to H3K4me3 and H3K4me1 histone modifications, specialized chromatin configurations (presence of the H2A.Z histone variant and binding of RNA Pol II. SIN-MLV and MLV integration clusters and hot spots overlap in most cases and are generated at a comparable frequency, indicating that the reduced genotoxicity of SIN-MLV vectors in hematopoietic cells is not due to a modified integration profile.

Human T-cell leukemia virus types I and II exhibit different DNase I protection patterns

International Nuclear Information System (INIS)

Altman, R.; Harrich, D.; Garcia, J.A.; Gaynor, R.B.

1988-01-01

Human T-cell leukemia virus types I (HTLV-I) and II (HTLV-II) are human retroviruses which normally infect T-lymphoid cells. HTLV-I infection is associated with adult T-cell leukemia-lymphoma, and HTLV-II is associated with an indolent form of hairy-cell leukemia. To identify potential transcriptional regulatory elements of these two related human retroviruses, the authors performed DNase I footprinting of both the HTLV-I and HTLV-II long terminal repeats (LTRs) by using extracts prepared from uninfected T cells, HTLV-I and HTLV-II transformed T cells, and HeLa cells. Five regions of the HTLV-I LTR and three regions of the HTLV-II LTR showed protection by DNase I footprinting. All three of the 21-base-pair repeats previously shown to be important in HTLV transcriptional regulation were protected in the HTLV-I LTR, whereas only one of these repeats was protected in the HTLV-II LTR. Several regions exhibited altered protection in extracts prepared from lymphoid cells as compared with HeLa cells, but there were minimal differences in the protection patterns between HTLV-infected and uninfected lymphoid extracts. A number of HTLV-I and HTLV-II LTR fragments which contained regions showing protection in DNase I footprinting were able to function as inducible enhancer elements in transient CAT gene expression assays in the presence of the HTLV-II tat protein. The alterations in the pattern of the cellular proteins which bind to the HTLV-I and HTLV-II LTRs may in part be responsible for differences in the transcriptional regulation of these two related viruses

Effects of As2O3 on DNA methylation, genomic instability, and LTR retrotransposon polymorphism in Zea mays.

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Erturk, Filiz Aygun; Aydin, Murat; Sigmaz, Burcu; Taspinar, M Sinan; Arslan, Esra; Agar, Guleray; Yagci, Semra

2015-12-01

Arsenic is a well-known toxic substance on the living organisms. However, limited efforts have been made to study its DNA methylation, genomic instability, and long terminal repeat (LTR) retrotransposon polymorphism causing properties in different crops. In the present study, effects of As2O3 (arsenic trioxide) on LTR retrotransposon polymorphism and DNA methylation as well as DNA damage in Zea mays seedlings were investigated. The results showed that all of arsenic doses caused a decreasing genomic template stability (GTS) and an increasing Random Amplified Polymorphic DNAs (RAPDs) profile changes (DNA damage). In addition, increasing DNA methylation and LTR retrotransposon polymorphism characterized a model to explain the epigenetically changes in the gene expression were also found. The results of this experiment have clearly shown that arsenic has epigenetic effect as well as its genotoxic effect. Especially, the increasing of polymorphism of some LTR retrotransposon under arsenic stress may be a part of the defense system against the stress.

Rapid turnover of 2-LTR HIV-1 DNA during early stage of highly active antiretroviral therapy.

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Weijun Zhu

Full Text Available BACKGROUND: Despite prolonged treatment with highly active antiretroviral therapy (HAART, the infectious HIV-1 continues to replicate and resides latently in the resting memory CD4+ T lymphocytes, which blocks the eradication of HIV-1. The viral persistence of HIV-1 is mainly caused by its proviral DNA being either linear nonintegrated, circular nonintegrated, or integrated. Previous reports have largely focused on the dynamics of HIV-1 DNA from the samples collected with relatively long time intervals during the process of disease and HAART treatment, which may have missed the intricate changes during the intervals in early treatment. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we investigated the dynamics of HIV-1 DNA in patients during the early phase of HARRT treatment. Using optimized real time PCR, we observed significant changes in 2-LTR during the first 12-week of treatment, while total and integrated HIV-1 DNA remained stable. The doubling time and half-life of 2-LTR were not correlated with the baseline and the rate of changes in plasma viral load and various CD4+ T-cell populations. Longitudinal analyses on 2-LTR sequences and plasma lipopolysaccharide (LPS levels did not reveal any significant changes in the same treatment period. CONCLUSIONS/SIGNIFICANCE: Our study revealed the rapid changes in 2-LTR concentration in a relatively large number of patients during the early HAART treatment. The rapid changes indicate the rapid infusion and clearance of cells bearing 2-LTR in the peripheral blood. Those changes are not expected to be caused by the blocking of viral integration, as our study did not include the integrase inhibitor raltegravir. Our study helps better understand the dynamics of HIV-DNA and its potential role as a biomarker for the diseases and for the treatment efficacy of HAART.

Studies on emerging radiation leukemia virus variants in C57BL/Ka mice

International Nuclear Information System (INIS)

Rassart, E.; Shang, M.; Boie, Y.; Jolicoeur, P.

1986-01-01

To analyze the emergence of radiation leukemia virus (RadLV) variants in primary X-ray-induced C57BL/Ka thymoma and to identify the virus responsible for the very high leukemogenic potential of passaged Kaplan strain BL/VL3 preparation, we cloned several primary and passaged ecotropic RadLV infectious genomes. By restriction analysis, we found that BL/VL3 cells harbor three related but different ecotropic RadLVs. Their restriction map differs significantly from those of primary RadLVs. Hybridization analysis also indicated that BL/VL3 and primary RadLVs differ in their p15E and long terminal repeat (LTR) regions. The LTR sequence of primary weakly leukemogenic RadLV has only one change, a C-rich sequence, generating a 6-base-pair direct repeat just in front of the promotor. The LTR of the primary nonleukemogenic RadLV only showed few base changes, mainly clustered in R and U5. The LTR from a moderately leukemogenic passaged BL/VL3 RadLV had conserved the C-rich sequence and acquired a 43-base-pair direct repeat in U3 and several other point mutations, small insertions, and deletions scattered in U3, R, and U5. All cloned primary RadLVs were fibrotropic, and some were weakly leukemogenic. All cloned BL/VL3 RadLVs were thymotropic and nonfibrotropic. The block of their replication was found to be after the synthesis of unintegrated linear and supercoiled viral DNA. Most of the BL/VL3 RadLVs were moderately leukemogenic, and one (V-13) was highly leukemogenic, being as virulent as the Moloney strain. We propose a model for the emergence of the RadLV variants and show that the virus responsible for the high leukemogenic potential of BL/VL3 preparation is a nondefective, ecotropic, lymphotropic, nonfibrotropic, unique retrovirus which most likely arose from a parental primary RadLV similar to those studied here

Genome-wide analysis of LTR-retrotransposons in oil palm.

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Beulé, Thierry; Agbessi, Mawussé Dt; Dussert, Stephane; Jaligot, Estelle; Guyot, Romain

2015-10-15

The oil palm (Elaeis guineensis Jacq.) is a major cultivated crop and the world's largest source of edible vegetable oil. The genus Elaeis comprises two species E. guineensis, the commercial African oil palm and E. oleifera, which is used in oil palm genetic breeding. The recent publication of both the African oil palm genome assembly and the first draft sequence of its Latin American relative now allows us to tackle the challenge of understanding the genome composition, structure and evolution of these palm genomes through the annotation of their repeated sequences. In this study, we identified, annotated and compared Transposable Elements (TE) from the African and Latin American oil palms. In a first step, Transposable Element databases were built through de novo detection in both genome sequences then the TE content of both genomes was estimated. Then putative full-length retrotransposons with Long Terminal Repeats (LTRs) were further identified in the E. guineensis genome for characterization of their structural diversity, copy number and chromosomal distribution. Finally, their relative expression in several tissues was determined through in silico analysis of publicly available transcriptome data. Our results reveal a congruence in the transpositional history of LTR retrotransposons between E. oleifera and E. guineensis, especially the Sto-4 family. Also, we have identified and described 583 full-length LTR-retrotransposons in the Elaeis guineensis genome. Our work shows that these elements are most likely no longer mobile and that no recent insertion event has occurred. Moreover, the analysis of chromosomal distribution suggests a preferential insertion of Copia elements in gene-rich regions, whereas Gypsy elements appear to be evenly distributed throughout the genome. Considering the high proportion of LTR retrotransposon in the oil palm genome, our work will contribute to a greater understanding of their impact on genome organization and evolution

Are endogenous feline leukemia viruses really endogenous?

Science.gov (United States)

Stewart, H; Jarrett, O; Hosie, M J; Willett, B J

2011-10-15

Full length endogenous feline leukemia virus (FeLV) proviruses exist within the genomes of many breeds of domestic cat raising the possibility that they may also exist in a transmissible exogenous form. Such viruses would share receptor usage with the recombinant FeLV-B subgroup, a viral subgroup that arises in vivo by recombination between exogenous subgroup A virus (FeLV-A) and endogenous FeLV. Accordingly, all isolates of FeLV-B made to date have contained a "helper" FeLV-A, consistent with their recombinatorial origin. In order to assess whether endogenous viruses are transmitted between cats, we examined primary isolates of FeLV for which the viral subgroup had been determined for the presence of a subgroup B virus that lacked an FeLV-A. Here we describe the identification of two primary field isolates of FeLV (2518 and 4314) that appeared to contain subgroup B virus only by classical interference assays, raising the possibility of between-host transmission of endogenous FeLV. Sequencing of the env gene and U3 region of the 3' long terminal repeat (LTR) confirmed that both viral genomes contained endogenous viral env genes. However the viral 3' LTRs appeared exogenous in origin with a putative 3' recombination breakpoint residing at the 3' end of the env gene. Further, the FeLV-2518 virions also co-packaged a truncated FeLV-A genome containing a defective env gene, termed FeLV-2518(A) whilst no helper subgroup A viral genome was detected in virions of FeLV-4314. The acquisition of an exogenous LTR by the endogenous FeLV in 4314 may have allowed a recombinant FeLV variant to outgrow an exogenous FeLV-A virus that was presumably present during first infection. Given time, a similar evolution may also occur within the 2518 isolate. The data suggest that endogenous FeLVs may be mobilised by acquisition of exogenous LTRs yielding novel viruses that type biologically as FeLV-B. Copyright © 2011 Elsevier B.V. All rights reserved.

Identification of a non-LTR retrotransposon from the gypsy moth

Science.gov (United States)

K.J. Garner; J.M. Slavicek

1999-01-01

A family of highly repetitive elements, named LDT1, has been identified in the gypsy moth, Lymantria dispar. The complete element is 5.4 kb in length and lacks long-terminal repeats, The element contains two open reading frames with a significant amino acid sequence similarity to several non-LTR retrotransposons. The first open reading frame contains...

Dimerization of BTas is required for the transactivational activity of bovine foamy virus

International Nuclear Information System (INIS)

Tan Juan; Qiao Wentao; Xu Fengwen; Han Hongqi; Chen Qimin; Geng Yunqi

2008-01-01

The BTas protein of bovine foamy virus (BFV) is a 249-amino-acid nuclear regulatory protein which transactivates viral gene expression directed by the long terminal repeat promoter (LTR) and the internal promoter (IP). Here, we demonstrate the BTas protein forms a dimeric complex in mammalian cells by using mammalian two hybrid systems and cross-linking assay. Functional analyses with deletion mutants reveal that the region of 46-62aa is essential for dimer formation. Furthermore, our results show that deleting the dimerization region of BTas did not affect the localization of BTas, but that it did result in the loss of its transactivational activity on the LTR and IP. Furthermore, BTas (Δ46-62aa) retained binding ability to the LTR and IP similar to that of the wild-type BTas. These data suggest the dimerization region is necessary for the transactivational function of BTas and is crucial to the replication of BFV

LTRsift: a graphical user interface for semi-automatic classification and postprocessing of de novo detected LTR retrotransposons.

Science.gov (United States)

Steinbiss, Sascha; Kastens, Sascha; Kurtz, Stefan

2012-11-07

Long terminal repeat (LTR) retrotransposons are a class of eukaryotic mobile elements characterized by a distinctive sequence similarity-based structure. Hence they are well suited for computational identification. Current software allows for a comprehensive genome-wide de novo detection of such elements. The obvious next step is the classification of newly detected candidates resulting in (super-)families. Such a de novo classification approach based on sequence-based clustering of transposon features has been proposed before, resulting in a preliminary assignment of candidates to families as a basis for subsequent manual refinement. However, such a classification workflow is typically split across a heterogeneous set of glue scripts and generic software (for example, spreadsheets), making it tedious for a human expert to inspect, curate and export the putative families produced by the workflow. We have developed LTRsift, an interactive graphical software tool for semi-automatic postprocessing of de novo predicted LTR retrotransposon annotations. Its user-friendly interface offers customizable filtering and classification functionality, displaying the putative candidate groups, their members and their internal structure in a hierarchical fashion. To ease manual work, it also supports graphical user interface-driven reassignment, splitting and further annotation of candidates. Export of grouped candidate sets in standard formats is possible. In two case studies, we demonstrate how LTRsift can be employed in the context of a genome-wide LTR retrotransposon survey effort. LTRsift is a useful and convenient tool for semi-automated classification of newly detected LTR retrotransposons based on their internal features. Its efficient implementation allows for convenient and seamless filtering and classification in an integrated environment. Developed for life scientists, it is helpful in postprocessing and refining the output of software for predicting LTR

Large-scale transcriptome data reveals transcriptional activity of fission yeast LTR retrotransposons

DEFF Research Database (Denmark)

Mourier, Tobias; Willerslev, Eske

2010-01-01

of transcriptional activity are observed from both strands of solitary LTR sequences. Transcriptome data collected during meiosis suggests that transcription of solitary LTRs is correlated with the transcription of nearby protein-coding genes. CONCLUSIONS: Presumably, the host organism negatively regulates...

Unexpected Modulation of Recall B and T Cell Responses after Immunization with Rotavirus-like Particles in the Presence of LT-R192G

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Christelle Basset

2010-08-01

Full Text Available LT-R192G, a mutant of the thermolabile enterotoxin of E. coli, is a potent adjuvant of immunization. Immune responses are generally analyzed at the end of protocols including at least 2 administrations, but rarely after a prime. To investigate this point, we compared B and T cell responses in mice after one and two intrarectal immunizations with 2/6 rotavirus-like particles (2/6-VLP and LT-R192G. After a boost, we found, an unexpected lower B cell expansion measured by flow cytometry, despite a secondary antibody response. We then analyzed CD4+CD25+Foxp3+ regulatory T cells (Tregs and CD4+CD25+Foxp3− helper T cells after in vitro (restimulation of mesenteric lymph node cells with the antigen (2/6-VLP, the adjuvant (LT-R192G or both. 2/6-VLP did not activate CD4+CD25+Foxp3− nor Foxp3+ T cells from non-immunized and 2/6-VLP immunized mice, whereas they did activate both subsets from mice immunized with 2/6-VLP in the presence of adjuvant. LT-R192G dramatically decreased CD4+CD25+Foxp3+ T cells from non-immunized and 2/6-VLP immunized mice but not from mice immunized with 2/6-VLP and adjuvant. Moreover, in this case, LT-R192G increased Foxp3 expression on CD4+CD25+Foxp3+ cells, suggesting specific Treg activation during the recall. Finally, when both 2/6-VLP and LT-R192G were used for restimulation, LT-R192G clearly suppressed both 2/6-VLP-specific CD4+CD25+Foxp3− and Foxp3+ T cells. All together, these results suggest that LT-R192G exerts different effects on CD4+CD25+Foxp3+ T cells, depending on a first or a second contact. The unexpected immunomodulation observed during the recall should be considered in designing vaccination protocols.

Ancient Origin of the U2 Small Nuclear RNA Gene-Targeting Non-LTR Retrotransposons Utopia.

Science.gov (United States)

Kojima, Kenji K; Jurka, Jerzy

2015-01-01

Most non-long terminal repeat (non-LTR) retrotransposons encoding a restriction-like endonuclease show target-specific integration into repetitive sequences such as ribosomal RNA genes and microsatellites. However, only a few target-specific lineages of non-LTR retrotransposons are distributed widely and no lineage is found across the eukaryotic kingdoms. Here we report the most widely distributed lineage of target sequence-specific non-LTR retrotransposons, designated Utopia. Utopia is found in three supergroups of eukaryotes: Amoebozoa, SAR, and Opisthokonta. Utopia is inserted into a specific site of U2 small nuclear RNA genes with different strength of specificity for each family. Utopia families from oomycetes and wasps show strong target specificity while only a small number of Utopia copies from reptiles are flanked with U2 snRNA genes. Oomycete Utopia families contain an "archaeal" RNase H domain upstream of reverse transcriptase (RT), which likely originated from a plant RNase H gene. Analysis of Utopia from oomycetes indicates that multiple lineages of Utopia have been maintained inside of U2 genes with few copy numbers. Phylogenetic analysis of RT suggests the monophyly of Utopia, and it likely dates back to the early evolution of eukaryotes.

LTRsift: a graphical user interface for semi-automatic classification and postprocessing of de novo detected LTR retrotransposons

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Steinbiss Sascha

2012-11-01

Full Text Available Abstract Background Long terminal repeat (LTR retrotransposons are a class of eukaryotic mobile elements characterized by a distinctive sequence similarity-based structure. Hence they are well suited for computational identification. Current software allows for a comprehensive genome-wide de novo detection of such elements. The obvious next step is the classification of newly detected candidates resulting in (super-families. Such a de novo classification approach based on sequence-based clustering of transposon features has been proposed before, resulting in a preliminary assignment of candidates to families as a basis for subsequent manual refinement. However, such a classification workflow is typically split across a heterogeneous set of glue scripts and generic software (for example, spreadsheets, making it tedious for a human expert to inspect, curate and export the putative families produced by the workflow. Results We have developed LTRsift, an interactive graphical software tool for semi-automatic postprocessing of de novo predicted LTR retrotransposon annotations. Its user-friendly interface offers customizable filtering and classification functionality, displaying the putative candidate groups, their members and their internal structure in a hierarchical fashion. To ease manual work, it also supports graphical user interface-driven reassignment, splitting and further annotation of candidates. Export of grouped candidate sets in standard formats is possible. In two case studies, we demonstrate how LTRsift can be employed in the context of a genome-wide LTR retrotransposon survey effort. Conclusions LTRsift is a useful and convenient tool for semi-automated classification of newly detected LTR retrotransposons based on their internal features. Its efficient implementation allows for convenient and seamless filtering and classification in an integrated environment. Developed for life scientists, it is helpful in postprocessing and refining

Intrinsic Stability of Episomal Circles Formed during Human Immunodeficiency Virus Type 1 Replication

Science.gov (United States)

Pierson, TheodoreC.; Kieffer, Tara L.; Ruff, Christian T.; Buck, Christopher; Gange, Stephen J.; Siliciano, Robert F.

2002-01-01

The development of surrogate markers capable of detecting residual ongoing human immunodeficiency virus type 1 (HIV-1) replication in patients receiving highly active antiretroviral therapy is an important step in understanding viral dynamics and in developing new treatment strategies. In this study, we evaluated the utility of circular forms of the viral genome for the detection of recent infection of cells by HIV-1. We measured the fate of both one-long terminal repeat (1-LTR) and 2-LTR circles following in vitro infection of logarithmically growing CD4+ T cells under conditions in which cell death was not a significant contributing factor. Circular forms of the viral genome were found to be highly stable and to decrease in concentration only as a function of dilution resulting from cell division. We conclude that these DNA circles are not intrinsically unstable in all cell types and suggest that the utility of 2-LTR circle assays in measuring recent HIV-1 infection of susceptible cells in vivo needs to be reevaluated. PMID:11907256

Mammalian-specific genomic functions: Newly acquired traits generated by genomic imprinting and LTR retrotransposon-derived genes in mammals.

Science.gov (United States)

Kaneko-Ishino, Tomoko; Ishino, Fumitoshi

2015-01-01

Mammals, including human beings, have evolved a unique viviparous reproductive system and a highly developed central nervous system. How did these unique characteristics emerge in mammalian evolution, and what kinds of changes did occur in the mammalian genomes as evolution proceeded? A key conceptual term in approaching these issues is "mammalian-specific genomic functions", a concept covering both mammalian-specific epigenetics and genetics. Genomic imprinting and LTR retrotransposon-derived genes are reviewed as the representative, mammalian-specific genomic functions that are essential not only for the current mammalian developmental system, but also mammalian evolution itself. First, the essential roles of genomic imprinting in mammalian development, especially related to viviparous reproduction via placental function, as well as the emergence of genomic imprinting in mammalian evolution, are discussed. Second, we introduce the novel concept of "mammalian-specific traits generated by mammalian-specific genes from LTR retrotransposons", based on the finding that LTR retrotransposons served as a critical driving force in the mammalian evolution via generating mammalian-specific genes.

Molecular epidemiology of endemic human T-lymphotropic virus type 1 in a rural community in Guinea-Bissau.

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Carla van Tienen

Full Text Available Human T-Lymphotropic Virus Type 1 (HTLV-1 infection causes lethal adult T-cell leukemia (ATL and severely debilitating HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP in up to 5% of infected adults. HTLV-1 is endemic in parts of Africa and the highest prevalence in West Africa (5% has been reported in Caio, a rural area in the North-West of Guinea-Bissau. It is not known which HTLV-1 variants are present in this community. Sequence data can provide insights in the molecular epidemiology and help to understand the origin and spread of HTLV-1.To gain insight into the molecular diversity of HTLV-1 in West Africa.HTLV-1 infected individuals were identified in community surveys between 1990-2007. The complete Long Terminal Repeat (LTR and p24 coding region of HTLV-1 was sequenced from infected subjects. Socio-demographic data were obtained from community census and from interviews performed by fieldworkers. Phylogenetic analyses were performed to characterize the relationship between the Caio HTLV-1 and HTLV-1 from other parts of the world.LTR and p24 sequences were obtained from 72 individuals (36 LTR, 24 p24 only and 12 both. Consistent with the low evolutionary change of HTLV-1, many of the sequences from unrelated individuals showed 100% nucleotide identity. Most (45 of 46 of the LTR sequences clustered with the Cosmopolitan HTLV-1 subtype 1a, subgroup D (1aD. LTR and p24 sequences from two subjects were divergent and formed a significant cluster with HTLV-1 subtype 1g, and with the most divergent African Simian T-cell Lymphotropic Virus, Tan90.The Cosmopolitan HTLV-1 1aD predominates in this rural West African community. However, HTLV-1 subtype 1g is also present. This subtype has not been described before in West Africa and may be more widespread than previously thought. These data are in line with the hypothesis that multiple monkey-to-man zoonotic events are contributing to HTLV-1 diversity.

Silencing of human T-cell leukemia virus type I gene transcription by epigenetic mechanisms

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Mueller Nancy

2005-10-01

Full Text Available Abstract Background Human T-cell leukemia virus type I (HTLV-I causes adult T-cell leukemia (ATL after a long latent period. Among accessory genes encoded by HTLV-I, the tax gene is thought to play a central role in oncogenesis. However, Tax expression is disrupted by several mechanims including genetic changes of the tax gene, deletion/hypermethylation of 5'-LTR. To clarify the role of epigenetic changes, we analyzed DNA methylation and histone modification in the whole HTLV-I provirus genome. Results The gag, pol and env genes of HTLV-I provirus were more methylated than pX region, whereas methylation of 5'-LTR was variable and 3'-LTR was not methylated at all. In ATL cell lines, complete DNA methylation of 5'-LTR was associated with transcriptional silencing of viral genes. HTLV-I provirus was more methylated in primary ATL cells than in carrier state, indicating the association with disease progression. In seroconvertors, DNA methylation was already observed in internal sequences of provirus just after seroconversion. Taken together, it is speculated that DNA methylation first occurs in the gag, pol and env regions and then extends in the 5' and 3' directions in vivo, and when 5'-LTR becomes methylated, viral transcription is silenced. Analysis of histone modification in the HTLV-I provirus showed that the methylated provirus was associated with hypoacetylation. However, the tax gene transcript could not be detected in fresh ATL cells regardless of hyperacetylated histone H3 in 5'-LTR. The transcription rapidly recovered after in vitro culture in such ATL cells. Conclusion These results showed that epigenetic changes of provirus facilitated ATL cells to evade host immune system by suppressing viral gene transcription. In addition, this study shows the presence of another reversible mechanism that suppresses the tax gene transcription without DNA methylation and hypoacetylated histone.

Circular viral DNA detection and junction sequence analysis from PBMC of SHIV-infected cynomolgus monkeys with undetectable virus plasma RNA

International Nuclear Information System (INIS)

Cara, Andrea; Maggiorella, Maria Teresa; Bona, Roberta; Sernicola, Leonardo; Baroncelli, Silvia; Negri, Donatella R.M.; Leone, Pasqualina; Fagrouch, Zahra; Heeney, Jonathan; Titti, Fausto; Cafaro, Aurelio; Ensoli, Barbara

2004-01-01

Extrachromosomal forms of human immunodeficiency virus (HIV)-1 can be detected in peripheral blood mononuclear cell (PBMC) from HIV-infected patients in the absence of detectable viral replication and are thought to be a sign of active but cryptic virus replication. No information, however, are available on whether these forms are also present in animal models for acquired immunodeficiency syndrome (AIDS) and on their relation with other methods of detection of virus replication. To this aim, a polymerase chain reaction (PCR) approach was used to detect and analyze unintegrated circular 2-LTR-containing forms in PBMC of simian human immunodeficiency virus (SHIV)89.6P infected cynomolgus monkeys with RNA levels ranging between 1.8x10 6 and less than 50 copies/ml of plasma. 2-LTR forms were detected in 96.5% of monkeys' samples above 50 copies/ml of plasma, whereas they were present in 75.8% of monkeys' samples below 50 copies/ml of plasma. Persistence of unintegrated viral DNA in monkeys with undetectable plasma RNA could indicate either stability in non-dividing cells or ongoing low levels of viral replication in dividing cells

LTR retrotransposon dynamics in the evolution of the olive (Olea europaea) genome

Czech Academy of Sciences Publication Activity Database

Barghini, E.; Natali, L.; Giordani, T.; Cossu, R.M.; Scalabrin, S.; Cattonaro, F.; Šimková, Hana; Vrána, Jan; Doležel, Jaroslav; Morgante, M.; Cavallini, A.

2015-01-01

Roč. 22, č. 1 (2015), s. 91-100 ISSN 1340-2838 R&D Projects: GA ČR GBP501/12/G090; GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : LTR retrotransposons * next-generation sequencing * olive Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.267, year: 2015

Salicylic acid inhibits UV- and Cis-Pt-induced human immunodeficiency virus expression

International Nuclear Information System (INIS)

Woloschak, G.E.; Panozzo, J.; Libertin, C.R.; Schreck, S.; South Carolina Univ., Columbia, SC

1994-01-01

Previous studies have shown that exposure of HeLa cells stably transfected with a human immunodeficiency virus-long terminal repeat-chloramphenicol acetyl transferase (HIV-LTR-CAT) construct to UV light-induced expression from the HIV LTR. By culturing the cells with salicylic acid we demonstrated dose-dependent repression of this induced HIV expression. Repression was evident if salicylic acid was administered 2 h before, at the same time as, or up to 6 h after exposure to the DNA-damaging agent. The kinetics were similar for UV- and for cis-Pt-induced HIV expression, and induction was dependent on the UV dose or cis-Pt concentration added to the culture. These results suggest a role for the prostaglandins or the cyclooxygenase pathway or both in HIV induction mediated by DNA-damaging agents

Two cis-acting elements responsible for posttranscriptional trans-regulation of gene expression of human T-cell leukemia virus type I

International Nuclear Information System (INIS)

Seiki, Motoharu; Inoue, Junichiro; Hidaka, Makoto; Yoshida, Mitsuaki

1988-01-01

The pX sequence of human T-cell leukemia virus type I codes for two nuclear proteins, p40 tax and p27 rex and a cytoplasmic protein, p21 X-III . p40 tax activates transcription from the long terminal repeat (LTR), whereas p27 rex modulates posttranscriptional processing to accumulate gag and env mRNAs that retain intron sequences. In this paper, the authors identify two cis-acting sequence elements needed for regulation by p27 rex : a 5' splice signal and a specific sequence in the 3' LTR. These two sequence elements are sufficient for regulation by p27 rex ; expression of a cellular gene (metallothionein I) became sensitive to rex regulation when the LTR was inserted at the 3' end of this gene. The requirement for these two elements suggests and unusual regulatory mechanism of RNA processing in the nucleus

Genetic characterization and phylogeny of human T-cell lymphotropic virus type I from Chile.

Science.gov (United States)

Ramirez, E; Cartier, L; Villota, C; Fernandez, J

2002-03-20

Infection with Human T-Cell Lymphotropic Virus type I (HTLV-I) have been associated with the development of the HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP). Phylogenetic analyses of HTLV-I isolates have revealed that HTLV-I can be classified into three major groups: the Cosmopolitan, Central African and Melanesian. In the present study, we analyzed the tax, 5' ltr, gag, pol, and env sequences of proviruses of PBMC from ten HAM/TSP patients to investigate the phylogenetic characterization of HTLV-I in Chilean patients. HTLV-I provirus in PBMC from ten Chilean patients with HAM/TSP were amplified by PCR using primers of tax, 5' ltr, gag, pol, and env genes. Amplified products of the five genes were purified and nucleotide sequence was determined by the dideoxy termination procedure. DNA sequences were aligned with the CLUSTAL W program. The results of this study showed that the tax, 5' ltr, gag, pol, and env gene of the Chilean HTLV-I strains had a nucleotide homology ranged from 98.1 to 100%, 95 to 97%, 98.9 to 100%, 94 to 98%, and 94.2 to 98.5% respect to ATK-1 clone, respectively. According to molecular phylogeny with 5' ltr gene, the Chilean HTLV-I strains were grouped with each other suggesting one cluster included in Transcontinental subgroup.

Effects of gamma rays, ultraviolet radiation, sunlight, microwaves and electromagnetic fields on gene expression mediated by human immunodeficiency virus promoter

International Nuclear Information System (INIS)

Libertin, C.R.; Woloschak, G.E.; Panozzo, J.; Groh, K.R.; Chang-Liu, Chin-Mei; Schreck, S.

1994-01-01

Previous work by our group and others has shown the modulation of human immunodeficiency virus (HIV) promoter or long terminal repeat (LTR) after exposure to neutrons and ultraviolet radiations. Using HeLa cells stably transfected with a construct containing the chloramphenicol acetyl transferase (CAT) gene, the transcription of which is mediated by the HIV-LTR, we designed experiments to examine the effects of exposure to different types of radiation (such as γ rays, ultraviolet and sunlight irradiations, electromagnetic fields and microwaves) in HIV-LTR-driven expression of CAT. These results demonstrated ultraviolet-light-induced transcription from the HIV promoter, as has been shown by others. Exposure to other DNA-damaging agents such as γ rays and sunlight (with limited exposures) had no significant effect on transcription mediated by HIV-LTR, suggesting that induction of HIV is not mediated by just any type of DNA damage but rather may require specific types of DNA damage. Microwaves did not cause cell killing when cells in culture were exposed in high volumes of medium, and the same cells showed no changes in expression. When microwave exposure was carried out in low volumes of medium (so that excessive heat was generated) induction of HIV-LTR transcription (as assayed by CAT activity) was evident. Electromagnetic field exposures had no effect on expression of HIV-LTR. These results demonstrate that not all types of radiation and not all DNA-damaging agents are capable of inducing HIV. We hypothesize that induction of HIV transcription may be mediated by several different signals exposure to radiation. 22 refs., 8 figs

Cloning and heterologous expression of a hydrophobin gene Ltr.hyd from the tiger milk mushroom Lentinus tuber-regium in yeast-like cells of Tremella fuciformis

Directory of Open Access Journals (Sweden)

Dongmei Liu

2018-03-01

Full Text Available Background: Hydrophobins are small proteins secreted by filamentous fungi, which show a highly surface activity. Because of the signally self-assembling abilities and surface activities, hydrophobins were considered as candidates in many aspects, for example, stabilizing foams and emulsions in food products. Lentinus tuber-regium, known as tiger milk mushroom, is both an edible and medicinal sclerotium-producing mushroom. Up to now, the hydrophobins of L. tuber-regium have not been identified. Results: In this paper, a Class I hydrophobin gene, Ltr.hyd, was cloned from L. tuber-regium and expressed in the yeast-like cells of Tremella fuciformis mediated by Agrobacterium tumefaciens. The expression vector pGEH-GH was under the control of T. fuciformis glyceraldehyde-3-phosphate dehydrogenase gene (gpd promoter. The integration of Ltr.hyd into the genome of T. fuciformis was confirmed by PCR, Southern blot, fluorescence observation and quantitative real-time PCR (qRT-PCR. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE demonstrated that recombinant hydrophobin rLtr.HYD with an expected molecular mass of 13 kDa was extracted. The yield of rLtr.HYD was 0.66 mg/g dry weight. The emulsifying activity of rLtr.HYD was better than the typical food emulsifiers sodium caseinate and Tween 20. Conclusions: We evaluated the emulsifying property of hydrophobin Ltr.HYD, which can be potentially used as a food emulsifier. Keywords: Agrobacterium tumefaciens, Emulsifier, Expression vector, Filamentous fungi, Gel electrophoresis, Glyceraldehyde-3-phosphate dehydrogenase, Heterogenous expression, Hydrophobin, Quantitative real-time PCR, Southern blot, Surface activity

Genome-wide analysis of LTR-retrotransposon diversity and its impact on the evolution of the genus Helianthus (L.).

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Mascagni, Flavia; Giordani, Tommaso; Ceccarelli, Marilena; Cavallini, Andrea; Natali, Lucia

2017-08-18

Genome divergence by mobile elements activity and recombination is a continuous process that plays a key role in the evolution of species. Nevertheless, knowledge on retrotransposon-related variability among species belonging to the same genus is still limited. Considering the importance of the genus Helianthus, a model system for studying the ecological genetics of speciation and adaptation, we performed a comparative analysis of the repetitive genome fraction across ten species and one subspecies of sunflower, focusing on long terminal repeat retrotransposons at superfamily, lineage and sublineage levels. After determining the relative genome size of each species, genomic DNA was isolated and subjected to Illumina sequencing. Then, different assembling and clustering approaches allowed exploring the repetitive component of all genomes. On average, repetitive DNA in Helianthus species represented more than 75% of the genome, being composed mostly by long terminal repeat retrotransposons. Also, the prevalence of Gypsy over Copia superfamily was observed and, among lineages, Chromovirus was by far the most represented. Although nearly all the same sublineages are present in all species, we found considerable variability in the abundance of diverse retrotransposon lineages and sublineages, especially between annual and perennial species. This large variability should indicate that different events of amplification or loss related to these elements occurred following species separation and should have been involved in species differentiation. Our data allowed us inferring on the extent of interspecific repetitive DNA variation related to LTR-RE abundance, investigating the relationship between changes of LTR-RE abundance and the evolution of the genus, and determining the degree of coevolution of different LTR-RE lineages or sublineages between and within species. Moreover, the data suggested that LTR-RE abundance in a species was affected by the annual or perennial

On the role of the second coding exon of the HIV-1 Tat protein in virus replication and MHC class I downregulation

NARCIS (Netherlands)

Verhoef, K.; Bauer, M.; Meyerhans, A.; Berkhout, B.

1998-01-01

Tat is an essential protein of human immunodeficiency virus type 1 (HIV-1) and activates transcription from the viral long terminal repeat (LTR) promoter. The tat gene is composed of two coding exons of which the first, corresponding to the N-terminal 72 amino acid residues, has been reported to be

Myelodysplastic syndromes and acute myeloid leukemia in cats infected with feline leukemia virus clone33 containing a unique long terminal repeat.

Science.gov (United States)

Hisasue, Masaharu; Nagashima, Naho; Nishigaki, Kazuo; Fukuzawa, Isao; Ura, Shigeyoshi; Katae, Hiromi; Tsuchiya, Ryo; Yamada, Takatsugu; Hasegawa, Atsuhiko; Tsujimoto, Hajime

2009-03-01

Feline leukemia virus (FeLV) clone33 was obtained from a domestic cat with acute myeloid leukemia (AML). The long terminal repeat (LTR) of this virus, like the LTRs present in FeLV from other cats with AML, differs from the LTRs of other known FeLV in that it has 3 tandem direct 47-bp repeats in the upstream region of the enhancer (URE). Here, we injected cats with FeLV clone33 and found 41% developed myelodysplastic syndromes (MDS) characterized by peripheral blood cytopenias and dysplastic changes in the bone marrow. Some of the cats with MDS eventually developed AML. The bone marrow of the majority of cats with FeLV clone33 induced MDS produced fewer erythroid and myeloid colonies upon being cultured with erythropoietin or granulocyte-macrophage colony-stimulating factor (GM-SCF) than bone marrow from normal control cats. Furthermore, the bone marrow of some of the cats expressed high-levels of the apoptosis-related genes TNF-alpha and survivin. Analysis of the proviral sequences obtained from 13 cats with naturally occurring MDS reveal they also bear the characteristic URE repeats seen in the LTR of FeLV clone33 and other proviruses from cats with AML. Deletions and mutations within the enhancer elements are frequently observed in naturally occurring MDS as well as AML. These results suggest that FeLV variants that bear URE repeats in their LTR strongly associate with the induction of both MDS and AML in cats.

A specific insertion of a solo-LTR characterizes the Y-chromosome of Bryonia dioica (Cucurbitaceae).

Science.gov (United States)

Oyama, Ryan K; Silber, Martina V; Renner, Susanne S

2010-06-14

Relatively few species of flowering plants are dioecious and even fewer are known to have sex chromosomes. Current theory posits that homomorphic sex chromosomes, such as found in Bryonia dioica (Cucurbitaceae), offer insight into the early stages in the evolution of sex chromosomes from autosomes. Little is known about these early steps, but an accumulation of transposable element sequences has been observed on the Y-chromosomes of some species with heteromorphic sex chromosomes. Recombination, by which transposable elements are removed, is suppressed on at least part of the emerging Y-chromosome, and this may explain the correlation between the emergence of sex chromosomes and transposable element enrichment. We sequenced 2321 bp of the Y-chromosome in Bryonia dioica that flank a male-linked marker, BdY1, reported previously. Within this region, which should be suppressed for recombination, we observed a solo-LTR nested in a Copia-like transposable element. We also found other, presumably paralogous, solo-LTRs in a consensus sequence of the underlying Copia-like transposable element. Given that solo-LTRs arise via recombination events, it is noteworthy that we find one in a genomic region where recombination should be suppressed. Although the solo-LTR could have arisen before recombination was suppressed, creating the male-linked marker BdY1, our previous study on B. dioica suggested that BdY1 may not lie in the recombination-suppressed region of the Y-chromosome in all populations. Presence of a solo-LTR near BdY1 therefore fits with the observed correlation between retrotransposon accumulation and the suppression of recombination early in the evolution of sex chromosomes. These findings further suggest that the homomorphic sex chromosomes of B. dioica, the first organism for which genetic XY sex-determination was inferred, are evolutionarily young and offer reference information for comparative studies of other plant sex chromosomes.

Enhancement of Intranasal Vaccination in Mice with Deglycosylated Chain A Ricin by LTR72, a Novel Mucosal Adjuvant

National Research Council Canada - National Science Library

Kende, Meir; Del Giudice, Giuseppe; Rivera, Noelia; Hewetson, John

2006-01-01

.... However, in the presence of 4, 2, or 1 microg of the mucosal adjuvant LTR72, a mutant of the heat-labile enterotoxin of Escherichia coli, the low antibody response and protection were substantially enhanced...

Cocaine promotes both initiation and elongation phase of HIV-1 transcription by activating NF-κB and MSK1 and inducing selective epigenetic modifications at HIV-1 LTR

International Nuclear Information System (INIS)

Sahu, Geetaram; Farley, Kalamo; El-Hage, Nazira; Aiamkitsumrit, Benjamas; Fassnacht, Ryan; Kashanchi, Fatah; Ochem, Alex; Simon, Gary L.; Karn, Jonathan; Hauser, Kurt F.; Tyagi, Mudit

2015-01-01

Cocaine accelerates human immunodeficiency virus (HIV-1) replication by altering specific cell-signaling and epigenetic pathways. We have elucidated the underlying molecular mechanisms through which cocaine exerts its effect in myeloid cells, a major target of HIV-1 in central nervous system (CNS). We demonstrate that cocaine treatment promotes HIV-1 gene expression by activating both nuclear factor-kappa B (NF-ĸB) and mitogen- and stress-activated kinase 1 (MSK1). MSK1 subsequently catalyzes the phosphorylation of histone H3 at serine 10, and p65 subunit of NF-ĸB at 276th serine residue. These modifications enhance the interaction of NF-ĸB with P300 and promote the recruitment of the positive transcription elongation factor b (P-TEFb) to the HIV-1 LTR, supporting the development of an open/relaxed chromatin configuration, and facilitating the initiation and elongation phases of HIV-1 transcription. Results are also confirmed in primary monocyte derived macrophages (MDM). Overall, our study provides detailed insights into cocaine-driven HIV-1 transcription and replication. - Highlights: • Cocaine induces the initiation phase of HIV transcription by activating NF-ĸB. • Cocaine induced NF-ĸB phosphorylation promotes its interaction with P300. • Cocaine enhances the elongation phase of HIV transcription by stimulating MSK1. • Cocaine activated MSK1 catalyzes the phosphorylation of histone H3 at its Ser10. • Cocaine induced H3S10 phosphorylation facilitates the recruitment of P-TEFb at LTR

Cocaine promotes both initiation and elongation phase of HIV-1 transcription by activating NF-κB and MSK1 and inducing selective epigenetic modifications at HIV-1 LTR

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Sahu, Geetaram; Farley, Kalamo [Division of Infectious Diseases, Department of Medicine, George Washington University, Washington, DC (United States); El-Hage, Nazira [Virginia Commonwealth University, Richmond, VA (United States); Aiamkitsumrit, Benjamas; Fassnacht, Ryan [Division of Infectious Diseases, Department of Medicine, George Washington University, Washington, DC (United States); Kashanchi, Fatah [George Mason University, Manassas, VA (United States); Ochem, Alex [ICGEB, Wernher and Beit Building, Anzio Road, Observatory, 7925 Cape Town (South Africa); Simon, Gary L. [Division of Infectious Diseases, Department of Medicine, George Washington University, Washington, DC (United States); Karn, Jonathan [Case Western Reserve University, Cleveland, OH (United States); Hauser, Kurt F. [Virginia Commonwealth University, Richmond, VA (United States); Tyagi, Mudit, E-mail: tmudit@email.gwu.edu [Division of Infectious Diseases, Department of Medicine, George Washington University, Washington, DC (United States); Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington, DC 20037 (United States)

2015-09-15

Cocaine accelerates human immunodeficiency virus (HIV-1) replication by altering specific cell-signaling and epigenetic pathways. We have elucidated the underlying molecular mechanisms through which cocaine exerts its effect in myeloid cells, a major target of HIV-1 in central nervous system (CNS). We demonstrate that cocaine treatment promotes HIV-1 gene expression by activating both nuclear factor-kappa B (NF-ĸB) and mitogen- and stress-activated kinase 1 (MSK1). MSK1 subsequently catalyzes the phosphorylation of histone H3 at serine 10, and p65 subunit of NF-ĸB at 276th serine residue. These modifications enhance the interaction of NF-ĸB with P300 and promote the recruitment of the positive transcription elongation factor b (P-TEFb) to the HIV-1 LTR, supporting the development of an open/relaxed chromatin configuration, and facilitating the initiation and elongation phases of HIV-1 transcription. Results are also confirmed in primary monocyte derived macrophages (MDM). Overall, our study provides detailed insights into cocaine-driven HIV-1 transcription and replication. - Highlights: • Cocaine induces the initiation phase of HIV transcription by activating NF-ĸB. • Cocaine induced NF-ĸB phosphorylation promotes its interaction with P300. • Cocaine enhances the elongation phase of HIV transcription by stimulating MSK1. • Cocaine activated MSK1 catalyzes the phosphorylation of histone H3 at its Ser10. • Cocaine induced H3S10 phosphorylation facilitates the recruitment of P-TEFb at LTR.

Enhancement of Intranasal Vaccination in Mice with Deglycosylated Chain A Ricin by LTR72, a Novel Mucosal Adjuvant

National Research Council Canada - National Science Library

Kende, Meir; Del Giudice, Giuseppe; Rivera, Noelia; Hewetson, John

2006-01-01

.... However, in the presence of 4, 2, or 1 micro-gram of the mucosal adjuvant LTR72, a mutant of the heat-labile enterotoxin of Escherichia coli, the low antibody response and protection were substantially enhanced...

Diversity, distribution and dynamics of full-length Copia and Gypsy LTR retroelements in Solanum lycopersicum.

Science.gov (United States)

Paz, Rosalía Cristina; Kozaczek, Melisa Eliana; Rosli, Hernán Guillermo; Andino, Natalia Pilar; Sanchez-Puerta, Maria Virginia

2017-10-01

Transposable elements are the most abundant components of plant genomes and can dramatically induce genetic changes and impact genome evolution. In the recently sequenced genome of tomato (Solanum lycopersicum), the estimated fraction of elements corresponding to retrotransposons is nearly 62%. Given that tomato is one of the most important vegetable crop cultivated and consumed worldwide, understanding retrotransposon dynamics can provide insight into its evolution and domestication processes. In this study, we performed a genome-wide in silico search of full-length LTR retroelements in the tomato nuclear genome and annotated 736 full-length Gypsy and Copia retroelements. The dispersion level across the 12 chromosomes, the diversity and tissue-specific expression of those elements were estimated. Phylogenetic analysis based on the retrotranscriptase region revealed the presence of 12 major lineages of LTR retroelements in the tomato genome. We identified 97 families, of which 77 and 20 belong to the superfamilies Copia and Gypsy, respectively. Each retroelement family was characterized according to their element size, relative frequencies and insertion time. These analyses represent a valuable resource for comparative genomics within the Solanaceae, transposon-tagging and for the design of cultivar-specific molecular markers in tomato.

Evolutionary characterization of Ty3/gypsy-like LTR retrotransposons in the parasitic cestode Echinococcus granulosus.

Science.gov (United States)

Bae, Young-An

2016-11-01

Cyclophyllidean cestodes including Echinococcus granulosus have a smaller genome and show characteristics such as loss of the gut, a segmented body plan, and accelerated growth rate in hosts compared with other tissue-invading helminths. In an effort to address the molecular mechanism relevant to genome shrinkage, the evolutionary status of long-terminal-repeat (LTR) retrotransposons, which are known as the most potent genomic modulators, was investigated in the E. granulosus draft genome. A majority of the E. granulosus LTR retrotransposons were classified into a novel characteristic clade, named Saci-2, of the Ty3/gypsy family, while the remaining elements belonged to the CsRn1 clade of identical family. Their nucleotide sequences were heavily corrupted by frequent base substitutions and segmental losses. The ceased mobile activity of the major retrotransposons and the following intrinsic DNA loss in their inactive progenies might have contributed to decrease in genome size. Apart from the degenerate copies, a gag gene originating from a CsRn1-like element exhibited substantial evidences suggesting its domestication including a preserved coding profile and transcriptional activity, the presence of syntenic orthologues in cestodes, and selective pressure acting on the gene. To my knowledge, the endogenized gag gene is reported for the first time in invertebrates, though its biological function remains elusive.

Structure and possible function of a G-quadruplex in the long terminal repeat of the proviral HIV-1 genome.

Science.gov (United States)

De Nicola, Beatrice; Lech, Christopher J; Heddi, Brahim; Regmi, Sagar; Frasson, Ilaria; Perrone, Rosalba; Richter, Sara N; Phan, Anh Tuân

2016-07-27

The long terminal repeat (LTR) of the proviral human immunodeficiency virus (HIV)-1 genome is integral to virus transcription and host cell infection. The guanine-rich U3 region within the LTR promoter, previously shown to form G-quadruplex structures, represents an attractive target to inhibit HIV transcription and replication. In this work, we report the structure of a biologically relevant G-quadruplex within the LTR promoter region of HIV-1. The guanine-rich sequence designated LTR-IV forms a well-defined structure in physiological cationic solution. The nuclear magnetic resonance (NMR) structure of this sequence reveals a parallel-stranded G-quadruplex containing a single-nucleotide thymine bulge, which participates in a conserved stacking interaction with a neighboring single-nucleotide adenine loop. Transcription analysis in a HIV-1 replication competent cell indicates that the LTR-IV region may act as a modulator of G-quadruplex formation in the LTR promoter. Consequently, the LTR-IV G-quadruplex structure presented within this work could represent a valuable target for the design of HIV therapeutics. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Gp85 genetic diversity of avian leukosis virus subgroup J among different individual chickens from a native flock.

Science.gov (United States)

Li, Yang; Fu, Jiayuan; Cui, Shuai; Meng, Fanfeng; Cui, Zhizhong; Fan, Jianhua; Chang, Shuang; Zhao, Peng

2017-05-01

To compare the genetic diversity and quasispecies evolution of avian leukosis virus (ALV) among different individuals, 5 chickens, raised in Shandong Provice of China, were randomly selected from a local chicken flock associated with serious tumor cases. Blood samples were collected and inoculated into chicken embryo fibroblast and DF-1 cell lines for virus isolation and identification, respectively, of Marek's disease virus (MDV), reticuloendotheliosis virus (REV), and ALV. Five strains of ALV subgroup J (ALV-J) were identified, and the gp85 gene from each strain was amplified and cloned. For each strain, about 20 positive clones of gp85 gene were selected for sequence analyses and the variability of the quasispecies of the 5 strains was compared. The results showed that the nuclear acid length of gp85 gene of 5 ALV-J isolates is 921 bp, 921 bp, 924 bp, 918 bp, and 912 bp respectively, and amino acid homologies of different gp85 clones from the 5 ALV-J strains were 99.3 to 100%, 99.3 to 100%, 99.4 to 100%, 98.4 to 100%, 99.0 to 100%, respectively. The proportions of dominant quasispecies were 65.0%, 85.0%, 85.0%, 50.0%, 84.2%, respectively, and homology of the gp85 among these dominant quasispecies was 89.2 to 92.5%. These data demonstrated the composition of the ALV-J quasispecies varied among infected individuals even within the same flock, and the dominant quasispecies continued to evolve both for their proportion and gene mutation. © 2016 Poultry Science Association Inc.

Genetic alterations of the long terminal repeat of an ecotropic porcine endogenous retrovirus during passage in human cells

International Nuclear Information System (INIS)

Denner, Joachim; Specke, Volker; Thiesen, Ulla; Karlas, Alexander; Kurth, Reinhard

2003-01-01

Human-tropic porcine endogenous retroviruses (PERV) such as PERV-A and PERV-B can infect human cells and are therefore a potential risk to recipients of xenotransplants. A similar risk is posed by recombinant viruses containing the receptor-binding site of PERV-A and large parts of the genome of the ecotropic PERV-C including its long terminal repeat (LTR). We describe here the unique organization of the PERV-C LTR and its changes during serial passage of recombinant virus in human cells. An increase in virus titer correlated with an increase in LTR length, caused by multiplication of 37-bp repeats containing nuclear factor Y binding sites. Luciferase dual reporter assays revealed a correlation between the number of repeats and the extent of expression. No alterations have been observed in the receptor-binding site, indicating that the increased titer is due to the changes in the LTR. These data indicate that recombinant PERVs generated during infection of human cells can adapt and subsequently replicate with greater efficiency

An adenovirus vectored mucosal adjuvant augments protection of mice immunized intranasally with an adenovirus-vectored foot-and-mouth disease virus subunit vaccine.

Science.gov (United States)

Alejo, Diana M; Moraes, Mauro P; Liao, Xiaofen; Dias, Camila C; Tulman, Edan R; Diaz-San Segundo, Fayna; Rood, Debra; Grubman, Marvin J; Silbart, Lawrence K

2013-04-26

Foot-and-mouth disease virus (FMDV) is a highly contagious pathogen that causes severe morbidity and economic losses to the livestock industry in many countries. The oral and respiratory mucosae are the main ports of entry of FMDV, so the stimulation of local immunity in these tissues may help prevent initial infection and viral spread. E. coli heat-labile enterotoxin (LT) has been described as one of the few molecules that have adjuvant activity at mucosal surfaces. The objective of this study was to evaluate the efficacy of replication-defective adenovirus 5 (Ad5) vectors encoding either of two LT-based mucosal adjuvants, LTB or LTR72. These vectored adjuvants were delivered intranasally to mice concurrent with an Ad5-FMDV vaccine (Ad5-A24) to assess their ability to augment mucosal and systemic humoral immune responses to Ad5-A24 and protection against FMDV. Mice receiving Ad5-A24 plus Ad5-LTR72 had higher levels of mucosal and systemic neutralizing antibodies than those receiving Ad5-A24 alone or Ad5-A24 plus Ad5-LTB. The vaccine plus Ad5-LTR72 group also demonstrated 100% survival after intradermal challenge with a lethal dose of homologous FMDV serotype A24. These results suggest that Ad5-LTR72 could be used as an important tool to enhance mucosal and systemic immunity against FMDV and potentially other pathogens with a common route of entry. Copyright © 2013 Elsevier Ltd. All rights reserved.

Identification of an osteoclast transcription factor that binds to the human T cell leukemia virus type I-long terminal repeat enhancer element.

Science.gov (United States)

Inoue, D; Santiago, P; Horne, W C; Baron, R

1997-10-03

Transgenic mice expressing human T cell leukemia virus type I (HTLV-I)-tax under the control of HTLV-I-long terminal repeat (LTR) promoter develop skeletal abnormalities with high bone turnover and myelofibrosis. In these animals, Tax is highly expressed in bone with a pattern of expression restricted to osteoclasts and spindle-shaped cells within the endosteal myelofibrosis. To test the hypothesis that lineage-specific transcription factors promote transgene expression from the HTLV-I-LTR in osteoclasts, we first examined tax expression in transgenic bone marrow cultures. Expression was dependent on 1alpha,25-dihydroxycholecalciferol and coincided with tartrate-resistant acid phosphatase (TRAP) expression, a marker of osteoclast differentiation. Furthermore, Tax was expressed in vitronectin receptor-positive mononuclear precursors as well as in mature osteoclast-like cells (OCLs). Consistent with our hypothesis, electrophoretic mobility shift assays revealed the presence of an OCL nuclear factor (NFOC-1) that binds to the LTR 21-base pair direct repeat, a region critical for the promoter activity. This binding is further enhanced by Tax. Since NFOC-1 is absent in macrophages and conserved in osteoclasts among species including human, such a factor may play a role in lineage determination and/or in expression of the differentiated osteoclast phenotype.

DNA cytosine methylation in the bovine leukemia virus promoter is associated with latency in a lymphoma-derived B-cell line: potential involvement of direct inhibition of cAMP-responsive element (CRE)-binding protein/CRE modulator/activation transcription factor binding.

Science.gov (United States)

Pierard, Valérie; Guiguen, Allan; Colin, Laurence; Wijmeersch, Gaëlle; Vanhulle, Caroline; Van Driessche, Benoît; Dekoninck, Ann; Blazkova, Jana; Cardona, Christelle; Merimi, Makram; Vierendeel, Valérie; Calomme, Claire; Nguyên, Thi Liên-Anh; Nuttinck, Michèle; Twizere, Jean-Claude; Kettmann, Richard; Portetelle, Daniel; Burny, Arsène; Hirsch, Ivan; Rohr, Olivier; Van Lint, Carine

2010-06-18

Bovine leukemia virus (BLV) proviral latency represents a viral strategy to escape the host immune system and allow tumor development. Besides the previously demonstrated role of histone deacetylation in the epigenetic repression of BLV expression, we showed here that BLV promoter activity was induced by several DNA methylation inhibitors (such as 5-aza-2'-deoxycytidine) and that overexpressed DNMT1 and DNMT3A, but not DNMT3B, down-regulated BLV promoter activity. Importantly, cytosine hypermethylation in the 5'-long terminal repeat (LTR) U3 and R regions was associated with true latency in the lymphoma-derived B-cell line L267 but not with defective latency in YR2 cells. Moreover, the virus-encoded transactivator Tax(BLV) decreased DNA methyltransferase expression levels, which could explain the lower level of cytosine methylation observed in the L267(LTaxSN) 5'-LTR compared with the L267 5'-LTR. Interestingly, DNA methylation inhibitors and Tax(BLV) synergistically activated BLV promoter transcriptional activity in a cAMP-responsive element (CRE)-dependent manner. Mechanistically, methylation at the -154 or -129 CpG position (relative to the transcription start site) impaired in vitro binding of CRE-binding protein (CREB) transcription factors to their respective CRE sites. Methylation at -129 CpG alone was sufficient to decrease BLV promoter-driven reporter gene expression by 2-fold. We demonstrated in vivo the recruitment of CREB/CRE modulator (CREM) and to a lesser extent activating transcription factor-1 (ATF-1) to the hypomethylated CRE region of the YR2 5'-LTR, whereas we detected no CREB/CREM/ATF recruitment to the hypermethylated corresponding region in the L267 cells. Altogether, these findings suggest that site-specific DNA methylation of the BLV promoter represses viral transcription by directly inhibiting transcription factor binding, thereby contributing to true proviral latency.

Human T-lymphotropic virus-1/2 detected in drug abused men who have sex with men in Surakarta Indonesia

Science.gov (United States)

Prasetyo, Afiono Agung; Sari, Yulia

2017-02-01

Human T-cell lymphotropic virus types 1 and 2 (HTLV-1/2) are retroviruses that probably among the most neglected blood-borne pathogens. The molecular epidemiology data of HTLV-1/2 in Indonesia is very rare. This study evaluated the prevalence of HTLV-1 and 2 in men who have sex with men with drug abused history in Surakarta Indonesia, to track the presentation of HTLV-1/2 in Indonesia. All blood samples collected from men who have sex with men with drug abused history in Surakarta in 2009-2013 were tested using enzyme linked immunosorbent assays and confirmed by RT-PCR nested addressed the part of HTLV-1 LTR and HTLV-2 LTR region, respectively. The specificity of the molecular assays was confirmed by sequencing the amplicons. The anti HTLV-1/2 positive rate was 4.8% (6/126). All positive serological samples were confirmed by nested RT-PCR. Of these, two was HTLV-1 positive and four was HTLV-2 positive. Molecular analysis of positive PCR products revealed that all HTLV-1 isolate had close relationship with HTLV-1 isolated in Japan while all HTLV-2 isolate with that of isolated in USA. HTLV-1 and HTLV-2 were detected in men who have sex with men with drug abused history in Surakarta indicated that these viruses were circulated in Indonesia, especially in the high risk communities

Coactivator-associated arginine methyltransferase 1 enhances transcriptional activity of the human T-cell lymphotropic virus type 1 long terminal repeat through direct interaction with Tax.

Science.gov (United States)

Jeong, Soo-Jin; Lu, Hanxin; Cho, Won-Kyung; Park, Hyeon Ung; Pise-Masison, Cynthia; Brady, John N

2006-10-01

In this study, we demonstrate that the coactivator-associated arginine methyltransferase 1 (CARM1), which methylates histone H3 and other proteins such as p300/CBP, is positively involved in the regulation of Tax transactivation. First, transfection studies demonstrated that overexpression of CARM1 wild-type protein resulted in increased Tax transactivation of the human T-cell lymphotropic virus type 1 (HTLV-1) long terminal repeat (LTR). In contrast, transfection of a catalytically inactive CARM1 methyltransferase mutant did not enhance Tax transactivation. CARM1 facilitated Tax transactivation of the CREB-dependent cellular GEM promoter. A direct physical interaction between HTLV-1 Tax and CARM1 was demonstrated using in vitro glutathione S-transferase-Tax binding assays, in vivo coimmunoprecipitation, and confocal microscopy experiments. Finally, chromatin immunoprecipitation analysis of the activated HTLV-1 LTR promoter showed the association of CARM1 and methylated histone H3 with the template DNA. In vitro, Tax facilitates the binding of CARM1 to the transcription complex. Together, our data provide evidence that CARM1 enhances Tax transactivation of the HTLV-1 LTR through a direct interaction between CARM1 and Tax and this binding promotes methylation of histone H3 (R2, R17, and R26).

Selection of reliable reference genes for gene expression studies in Trichoderma afroharzianum LTR-2 under oxalic acid stress.

Science.gov (United States)

Lyu, Yuping; Wu, Xiaoqing; Ren, He; Zhou, Fangyuan; Zhou, Hongzi; Zhang, Xinjian; Yang, Hetong

2017-10-01

An appropriate reference gene is required to get reliable results from gene expression analysis by quantitative real-time reverse transcription PCR (qRT-PCR). In order to identify stable and reliable reference genes in Trichoderma afroharzianum under oxalic acid (OA) stress, six commonly used housekeeping genes, i.e., elongation factor 1, ubiquitin, ubiquitin-conjugating enzyme, glyceraldehyde-3-phosphate dehydrogenase, α-tubulin, actin, from the effective biocontrol isolate T. afroharzianum strain LTR-2 were tested for their expression during growth in liquid culture amended with OA. Four in silico programs (comparative ΔCt, NormFinder, geNorm and BestKeeper) were used to evaluate the expression stabilities of six candidate reference genes. The elongation factor 1 gene EF-1 was identified as the most stably expressed reference gene, and was used as the normalizer to quantify the expression level of the oxalate decarboxylase coding gene OXDC in T. afroharzianum strain LTR-2 under OA stress. The result showed that the expression of OXDC was significantly up-regulated as expected. This study provides an effective method to quantify expression changes of target genes in T. afroharzianum under OA stress. Copyright © 2017 Elsevier B.V. All rights reserved.

The surface glycoprotein of a natural feline leukemia virus subgroup A variant, FeLV-945, as a determinant of disease outcome.

Science.gov (United States)

Bolin, Lisa L; Ahmad, Shamim; Levy, Laura S

2011-10-15

Feline leukemia virus (FeLV) is a natural retrovirus of domestic cats associated with degenerative, proliferative and malignant diseases. Studies of FeLV infection in a cohort of naturally infected cats were undertaken to examine FeLV variation, the selective pressures operative in FeLV infection that lead to predominance of natural variants, and the consequences for infection and disease progression. A unique variant, designated FeLV-945, was identified as the predominant isolate in the cohort and was associated with non-T-cell diseases including multicentric lymphoma. FeLV-945 was assigned to the FeLV-A subgroup based on sequence analysis and receptor utilization, but was shown to differ in sequence from a prototype member of FeLV-A, designated FeLV-A/61E, in the long terminal repeat (LTR) and the surface glycoprotein gene (SU). A unique sequence motif in the FeLV-945 LTR was shown to function as a transcriptional enhancer and to confer a replicative advantage. The FeLV-945 SU protein was observed to differ in sequence as compared to FeLV-A/61E within functional domains known to determine receptor selection and binding. Experimental infection of newborn cats was performed using wild type FeLV-A/61E or recombinant FeLV-A/61E in which the LTR (61E/945L) or LTR and SU (61E/945SL) were exchanged for that of FeLV-945. Infection with either FeLV-A/61E or 61E/945L resulted in T-cell lymphoma of the thymus, although 61E/945L caused disease significantly more rapidly. In contrast, infection with 61E/945SL resulted in the rapid induction of a multicentric lymphoma of B-cell origin, thus recapitulating the outcome of natural infection and implicating FeLV-945 SU as a determinant of disease outcome. Recombinant FeLV-B was detected infrequently and at low levels in multicentric lymphomas, and was thereby not implicated in disease induction. Preliminary studies of receptor interaction indicated that virus particles bearing FeLV-945 SU bind to the FeLV-A receptor more

Human T-lymphotropic Virus-1/2 detected in drug abused men who have sex with men infected with HIV in Surakarta, Indonesia

Science.gov (United States)

Agung Prasetyo, Afiono; Sari, Yulia

2018-05-01

Human T-lymphotropic virus types 1 and 2 (HTLV-1/2) share similar routes of transmission with human immunodeficiency virus (HIV), and the HTLV-1/2 co-infection may affect the clinical course of HIV infection. The HIV/HTLV-1/2 co-infection risk higher if the patient performing the high-risk activities. This study evaluated the presentation of HTLV-1 and 2 in HIV-infected men who have sex with men with drug abused history in Surakarta Indonesia. Blood samples collected from HIV-infected men who have sex with men with drug abused history in Surakarta were tested using HTLV-1/2 enzyme-linked immunosorbent assays and confirmed by RT-PCR nested addressed the part of HTLV-1 LTR and HTLV-2 LTR region, respectively. The specificity of the molecular assays was confirmed by sequencing the amplicons. The anti HTLV-1/2 positive rate was 17.4% (8/46). All positive serological samples were confirmed by nested RT-PCR. Of these, three was HTLV-1 positive and five was HTLV-2 positive. Molecular analysis of positive PCR products revealed that all HTLV-1 isolates had a close relationship with HTLV-1 isolated in Japan while all HTLV-2 isolates with that of isolated in the USA. HTLV-1 and HTLV-2 were detected in drug abused men who have sex with men infected with HIV in Surakarta.

Induction of transcription from the long terminal repeat of Moloney murine sarcoma provirus by UV-irradiation, x-irradiation, and phorbol ester

International Nuclear Information System (INIS)

Lin, C.S.; Goldthwait, D.A.; Samols, D.

1990-01-01

The long terminal repeat (LTR) of Moloney murine sarcoma virus (Mo-MuSV) was used as a model system to study the stress response of mammalian cells to physical carcinogens. The chloramphenicol acetyltransferase (CAT) gene was inserted between two Mo-MuSV LTRs, and the LTR-CAT-LTR construct was used for virus production and was integrated into the genome of NIH 3T3 cells in the proviral form. This construct was used to assure that the integrated CAT gene was driven by the promoter of the LTR. Expression of the CAT gene was stimulated 4-fold by UV irradiation, and the peak of activity was observed at 18 hr. In contrast, stimulation of the CAT expression after x-irradiation was 2-fold and occurred at 6 hr. Phorbol myristate acetate also stimulated CAT activity 4-fold with a peak at 6 hr. Down-regulation of protein kinase C blocked totally the response to x-irradiation but only partially the response to UV. The protein kinase inhibitor H7 blocked the response to treatment by UV, x-ray, and phorbol ester

A yeast model for target-primed (non-LTR retrotransposition

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Busby Jason N

2007-08-01

Full Text Available Abstract Background Target-primed (non-LTR retrotransposons, such as the human L1 element, are mobile genetic elements found in many eukaryotic genomes. They are often present in large numbers and their retrotransposition can cause mutations and genomic rearrangements. Despite their importance, many aspects of their replication are not well understood. Results We have developed a yeast model system for studying target-primed retrotransposons. This system uses the Zorro3 element from Candida albicans. A cloned copy of Zorro3, tagged with a retrotransposition indicator gene, retrotransposes at a high frequency when introduced into an appropriate C. albicans host strain. Retrotransposed copies of the tagged element exhibit similar features to the native copies, indicating that the natural retrotransposition pathway is being used. Retrotransposition is dependent on the products of the tagged element's own genes and is highly temperature-regulated. The new assay permits the analysis of the effects of specific mutations introduced into the cloned element. Conclusion This Zorro3 retrotransposition assay system complements previously available target-primed retrotransposition assays. Due to the relative simplicity of the growth, manipulation and analysis of yeast cells, the system should advance our understanding of target-primed retrotransposition.

Cocaine promotes both initiation and elongation phase of HIV-1 transcription by activating NF-κB and MSK1 and inducing selective epigenetic modifications at HIV-1 LTR

Science.gov (United States)

Sahu, Geetaram; Farley, Kalamo; El-Hage, Nazira; Aiamkitsumrit, Benjamas; Fassnacht, Ryan; Kashanchi, Fatah; Ochem, Alex; Simon, Gary L.; Karn, Jonathan; Hauser, Kurt F.; Tyagi, Mudit

2015-01-01

Cocaine accelerates human immunodeficiency virus (HIV-1) replication by altering specific cell-signaling and epigenetic pathways. We have elucidated the underlying molecular mechanisms through which cocaine exerts its effect in myeloid cells, a major target of HIV-1 in central nervous system (CNS). We demonstrate that cocaine treatment promotes HIV-1 gene expression by activating both nuclear factor-kappa B (NF-κB) and mitogen- and stress-activated kinase 1 (MSK1). MSK1 subsequently catalyzes the phosphorylation of histone H3 at serine 10, and p65 subunit of NF-κB at 276th serine residue. These modifications enhance the interaction of NF-κB with P300 and promote the recruitment of the positive transcription elongation factor b (P-TEFb) to the HIV-1 LTR, supporting the development of an open/relaxed chromatin configuration, and facilitating the initiation and elongation phases of HIV-1 transcription. Results are also confirmed in primary monocyte derived macrophages (MDM). Overall, our study provides detailed insights into cocaine-driven HIV-1 transcription and replication. PMID:25980739

Bond graph modeling and LQG/LTR controller design of magnetically levitation systems

International Nuclear Information System (INIS)

Kim, Jong Shik; Park, Jeon Soo

1991-01-01

A logical and systematic procedure to derive a mathematical model for magnetically levitation (MAGLEV) systems with a combined lift and guidance is developed by using bond graph modeling techniques. First, bond graph is contructed for the 1 st -dimensional MAGLEV system in which three subsystems (energy feeding, track and vehicle) are considered. And, the 2 nd -dimensional MAGLEV system in which lift and guidance dynamics are coupled is modeled by using the concept of multi-port field in bond graph languages. Finally, the LQG/LTR control system is designed for a multivariable MAGLEV system with stagger configuration type. In this paper, it has been shown that the bond graph is an excellent effective method for modeling multi-energy domain systems such as MAGLEV systems with uncertainties such as mass variations, track irregularities and wind gusts. (Author)

Bond graph modeling and LQG/LTR controller design of magnetically levitation systems

Energy Technology Data Exchange (ETDEWEB)

Kim, Jong Shik; Park, Jeon Soo [Busan National Univ. (Korea, Republic of)

1991-09-01

A logical and systematic procedure to derive a mathematical model for magnetically levitation (MAGLEV) systems with a combined lift and guidance is developed by using bond graph modeling techniques. First, bond graph is contructed for the 1{sup st}-dimensional MAGLEV system in which three subsystems (energy feeding, track and vehicle) are considered. And, the 2{sup nd}-dimensional MAGLEV system in which lift and guidance dynamics are coupled is modeled by using the concept of multi-port field in bond graph languages. Finally, the LQG/LTR control system is designed for a multivariable MAGLEV system with stagger configuration type. In this paper, it has been shown that the bond graph is an excellent effective method for modeling multi-energy domain systems such as MAGLEV systems with uncertainties such as mass variations, track irregularities and wind gusts. (Author).

Inhibition of human T cell leukemia virus type 2 replication by the suppressive action of class II transactivator and nuclear factor Y.

Science.gov (United States)

Tosi, Giovanna; Pilotti, Elisabetta; Mortara, Lorenzo; De Lerma Barbaro, Andrea; Casoli, Claudio; Accolla, Roberto S

2006-08-22

The master regulator of MHC-II gene transcription, class II transactivator (CIITA), acts as a potent inhibitor of human T cell leukemia virus type 2 (HTLV-2) replication by blocking the activity of the viral Tax-2 transactivator. Here, we show that this inhibitory effect takes place at the nuclear level and maps to the N-terminal 1-321 region of CIITA, where we identified a minimal domain, from positions 64-144, that is strictly required to suppress Tax-2 function. Furthermore, we show that Tax-2 specifically cooperates with cAMP response element binding protein-binding protein (CBP) and p300, but not with p300/CBP-associated factor, to enhance transcription from the viral promoter. This finding represents a unique difference with respect to Tax-1, which uses all three coactivators to transactivate the human T cell leukemia virus type 1 LTR. Direct sequestering of CBP or p300 is not the primary mechanism by which CIITA causes suppression of Tax-2. Interestingly, we found that the transcription factor nuclear factor Y, which interacts with CIITA to increase transcription of MHC-II genes, exerts a negative regulatory action on the Tax-2-mediated HTLV-2 LTR transactivation. Thus, CIITA may inhibit Tax-2 function, at least in part, through nuclear factor Y. These findings demonstrate the dual defensive role of CIITA against pathogens: it increases the antigen-presenting function for viral determinants and suppresses HTLV-2 replication in infected cells.

Mutations in the Lactococcus lactis Ll.LtrB group II intron that retain mobility in vivo

Directory of Open Access Journals (Sweden)

D'Souza Lisa M

2002-12-01

Full Text Available Abstract Background Group II introns are mobile genetic elements that form conserved secondary and tertiary structures. In order to determine which of the conserved structural elements are required for mobility, a series of domain and sub-domain deletions were made in the Lactococcus lactis group II intron (Ll.LtrB and tested for mobility in a genetic assay. Point mutations in domains V and VI were also tested. Results The largest deletion that could be made without severely compromising mobility was 158 nucleotides in DIVb(1–2. This mutant had a mobility frequency comparable to the wild-type Ll.LtrB intron (ΔORF construct. Hence, all subsequent mutations were done in this mutant background. Deletion of DIIb reduced mobility to approximately 18% of wild-type, while another deletion in domain II (nts 404–459 was mobile to a minor extent. Only two deletions in DI and none in DIII were tolerated. Some mobility was also observed for a DIVa deletion mutant. Of the three point mutants at position G3 in DV, only G3A retained mobility. In DVI, deletion of the branch-point nucleotide abolished mobility, but the presence of any nucleotide at the branch-point position restored mobility to some extent. Conclusions The smallest intron capable of efficient retrohoming was 725 nucleotides, comprising the DIVb(1–2 and DII(iia,b deletions. The tertiary elements found to be nonessential for mobility were alpha, kappa and eta. In DV, only the G3A mutant was mobile. A branch-point residue is required for intron mobility.

LQG/LTR [linear quadratic Gaussian with loop transfer recovery] robust control system design for a low-pressure feedwater heater train

International Nuclear Information System (INIS)

Murphy, G.V.; Bailey, J.M.

1990-01-01

This paper uses the linear quadratic Gaussian with loop transfer recovery (LQG/LTR) control system design method to obtain a level control system for a low-pressure feedwater heater train. The control system performance and stability robustness are evaluated for a given set of system design specifications. The tools for analysis are the return ratio, return difference, and inverse return difference singular-valve plots for a loop break at the plant output. 3 refs., 7 figs., 2 tabs

Cell-type-specific gene delivery into neuronal cells in vitro and in vivo

International Nuclear Information System (INIS)

Parveen, Zahida; Mukhtar, Muhammad; Rafi, Mohammed; Wenger, David A.; Siddiqui, Khwaja M.; Siler, Catherine A.; Dietzschold, Bernhard; Pomerantz, Roger J.; Schnell, Matthias J.; Dornburg, Ralph

2003-01-01

The avian retroviruses reticuloendotheliosis virus strain A (REV-A) and spleen necrosis virus (SNV) are not naturally infectious in human cells. However, REV-A-derived viral vectors efficiently infect human cells when they are pseudotyped with envelope proteins displaying targeting ligands specific for human cell-surface receptors. Here we report that vectors containing the gag region of REV-A and pol of SNV can be pseudotyped with the envelope protein of vesicular stomatitis virus (VSV) and the glycoproteins of different rabies virus (RV) strains. Vectors pseudotyped with the envelope protein of the highly neurotropic RV strain CVS-N2c facilitated cell type-specific gene delivery into mouse and human neurons, but did not infect other human cell types. Moreover, when such vector particles were injected into the brain of newborn mice, only neuronal cells were infected in vivo. Cell-type-specific gene delivery into neurons may present quite specific gene therapy approaches for many degenerative diseases of the brain

Endogenous MOV10 inhibits the retrotransposition of endogenous retroelements but not the replication of exogenous retroviruses.

Science.gov (United States)

Arjan-Odedra, Shetal; Swanson, Chad M; Sherer, Nathan M; Wolinsky, Steven M; Malim, Michael H

2012-06-22

The identification of cellular factors that regulate the replication of exogenous viruses and endogenous mobile elements provides fundamental understanding of host-pathogen relationships. MOV10 is a superfamily 1 putative RNA helicase that controls the replication of several RNA viruses and whose homologs are necessary for the repression of endogenous mobile elements. Here, we employ both ectopic expression and gene knockdown approaches to analyse the role of human MOV10 in the replication of a panel of exogenous retroviruses and endogenous retroelements. MOV10 overexpression substantially decreased the production of infectious retrovirus particles, as well the propagation of LTR and non-LTR endogenous retroelements. Most significantly, RNAi-mediated silencing of endogenous MOV10 enhanced the replication of both LTR and non-LTR endogenous retroelements, but not the production of infectious retrovirus particles demonstrating that natural levels of MOV10 suppress retrotransposition, but have no impact on infection by exogenous retroviruses. Furthermore, functional studies showed that MOV10 is not necessary for miRNA or siRNA-mediated mRNA silencing. We have identified novel specificity for human MOV10 in the control of retroelement replication and hypothesise that MOV10 may be a component of a cellular pathway or process that selectively regulates the replication of endogenous retroelements in somatic cells.

In vivo activation of human immunodeficiency virus type 1 long terminal repeat by UV type A (UV-A) light plus psoralen and UV-B light in the skin of transgenic mice

OpenAIRE

Morrey, John D; Bourn, S M; Bunch, T D; Jackson, M K; Sidwell, R W; Barrows, L R; Daynes, R A; Rosen, C A

1991-01-01

UV irradiation has been shown to activate the human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR) in cell culture; however, only limited studies have been described in vivo. UV light has been categorized as UV-A (400 to 315 nm), -B (315 to 280 nm), or -C (less than 280 nm); the longer wavelengths are less harmful but more penetrative. Highly penetrative UV-A radiation constitutes the vast majority of UV sunlight reaching the earth's surface but is normally harmless. UV-B ir...

Human T-lymphotropic virus type 1 prevalence in northeastern Iran, Sabzevar: an epidemiologic-based study and phylogenetic analysis.

Science.gov (United States)

Azarpazhooh, Mahmoud Reza; Hasanpour, Kazem; Ghanbari, Mohsen; Rezaee, S A Rahim; Mashkani, Baratali; Hedayati-Moghaddam, Mohammad Reza; Valizadeh, Narges; Farid Hosseini, Reza; Foroghipoor, Mohsen; Soltanifar, Azadeh; Sahebari, Maryam; Azadmanesh, Keyhan; Hassanshahi, Gholahossein; Rafatpanah, Houshang

2012-09-01

Human T-lymphotropic virus type 1 (HTLV-I) is an important global health problem in the world mainly in the endemic areas of HTLV-I infection. It was previously reported that Mashhad, in northeastern Iran, is a new endemic region of HTLV-I. The aim of this study was to examine the prevalence and phylogenetic analysis of HTLV-I in Sabzevar, located in the southeast of Mashhad. In this cross-sectional study 1445 individuals were selected by multistage cluster sampling. Serum samples were screened for anti-HTLV-I antibody using enzyme-linked immunosorbent assay (ELISA); all of the ELISA-positive samples were confirmed by polymerase chain reaction (PCR). Long terminal repeat (LTR) sequencing was carried out to determine the type of HTLV-I in Sabzevar. In the primary screening by ELISA, 26/1445 (1.8%) of those sampled were reactive for HTLV-I antibody. Twenty-four out of 26 samples were confirmed HTLV-I infection by PCR (24/1445). The overall prevalence of HTLV-I infection in Sabzevar is 1.66%. The prevalence of the virus infection in men and women was 2.42% (11/455) and 1.31% (13/989), respectively. Seroprevalence was associated with age, increasing significantly among those older than 30 years (p=0.015), and a history of surgery (p=0.002), imprisonment (p=0.018), and hospitalization (p=0.005). Three out of 24 positive HTLV-I samples were selected for sequencing and phylogenetic analysis of LTR. The results showed that HTLV-I in Sabzevar belonged to the cosmopolitan subtype. The present study showed Sabzevar is a new endemic area for HTLV-I infection. Our study emphasizes that systemic HTLV-I screening of blood donors in Sabzevar and other cities in Khorasan province is important and should be taken into account.

Protein domains involved in both in vivo and in vitro interactions between human T-cell leukemia virus type I tax and CREB.

Science.gov (United States)

Yin, M J; Paulssen, E J; Seeler, J S; Gaynor, R B

1995-06-01

Gene expression from the human T-cell leukemia virus type I (HTLV-I) long terminal repeat (LTR) is mediated by three cis-acting regulatory elements known as 21-bp repeats and the transactivator protein Tax. The 21-bp repeats can be subdivided into three motifs known as A, B, and C, each of which is important for maximal gene expression in response to Tax. The B motif contains nucleotide sequences known as a cyclic AMP response element (CRE) or tax-response element which binds members of the ATF/CREB family of transcription factors. Though mutations of this element in the HTLV-I LTR eliminate tax activation, Tax will not activate most other promoters containing these CRE sites. In this study, we investigated the mechanism by which Tax activates gene expression in conjunction with members of the ATF/CREB family. We found that Tax enhanced the binding of one member of the ATF/CREB family, CREB 1, to each of the three HTLV-I LTR 21-bp repeats but not another member designated CRE-BP1 or CREB2. Tax enhanced the binding of CREB1 to nonpalindromic CRE binding sites such as those found in the HTLV-I LTR, but Tax did not enhance the binding of CREB1 to palindromic CRE binding sites such as found in the somatostatin promoter. This finding may help explain the failure of Tax to activate promoters containing consensus CRE sites. These studies were extended by use of the mammalian two-hybrid system. Tax was demonstrated to interact directly with CREB1 but not with other bZIP proteins, including CREB2 and Jun. Site-directed mutagenesis of both Tax and CREB1 demonstrated that the amino terminus of Tax and both the basic and the leucine zipper regions of CREB1 were required for direct interactions between these proteins both in vivo and in vitro. This interaction occurred in vivo and thus did not require the presence of the HTLV-I 21-bp repeats, as previously suggested. These results define the domains required for interaction between Tax and CREB that are likely critical for the

Modulation of the Brd4/P-TEFb interaction by the human T-lymphotropic virus type 1 tax protein.

Science.gov (United States)

Cho, Won-Kyung; Zhou, Meisheng; Jang, Moon Kyoo; Huang, Keven; Jeong, Soo-Jin; Ozato, Keiko; Brady, John N

2007-10-01

Positive transcription elongation factor (P-TEFb), which is composed of CDK9 and cyclin T1, plays an important role in cellular and viral gene expression. Our lab has recently demonstrated that P-TEFb is required for Tax transactivation of the viral long terminal repeat (LTR). P-TEFb is found in two major complexes: the inactive form, which is associated with inhibitory subunits 7SK snRNA and HEXIM1, and the active form, which is associated with, at least in part, Brd4. In this study, we analyzed the effect of Brd4 on human T-lymphotropic virus type 1 (HTLV-1) transcription. Overexpression of Brd4 repressed Tax transactivation of the HTLV-1 LTR in a dose-dependent manner. In vitro binding studies suggest that Tax and Brd4 compete for binding to P-TEFb through direct interaction with cyclin T1. Tax interacts with cyclin T1 amino acids 426 to 533, which overlaps the region responsible for Brd4 binding. In vivo, overexpression of Tax decreased the amount of 7SK snRNA associated with P-TEFb and stimulates serine 2 phosphorylation of the RNA polymerase II carboxyl-terminal domain, suggesting that Tax regulates the functionality of P-TEFb. Our results suggest the possibility that Tax may compete and functionally substitute for Brd4 in P-TEFb regulation.

Human immunodeficiency virus type 1 KK26-27 matrix mutants display impaired infectivity, circularization and integration but not nuclear import

International Nuclear Information System (INIS)

Mannioui, Abdelkrim; Nelson, Elisabeth; Schiffer, Cecile

2005-01-01

We analyzed the role of human immunodeficiency virus (HIV)-1 matrix protein (MA) during the virus replication afferent phase. Single-round infection of H9 T lymphocytes showed that the combined mutation of MA Lys residues 26-27 in MA reported nuclear localization signal (NLS)-1 [Haffar, O.K., Popov, S., Dubrovsky, L., Agostini, I., Tang, H., Pushkarsky, T., Nadler, S.G., Bukrinsky, M., 2000. Two nuclear localization signals in the HIV-1 matrix protein regulate nuclear import of the HIV-1 pre-integration complex. J. Mol. Biol. 299 (2): 359-368] impaired infectivity, abrogated 2-LTR-circle formation and significantly reduced integration. However, the mutation did not affect viral DNA docking to chromatin in either interphasic or mitotic cells, indicating that MA N-terminal basic domain should not represent a major determinant of HIV-1 nuclear import in T lymphocytes. These data point to a previously unreported role of MA in the late, post-chromatin-binding, afferent phase of HIV-1 replication cycle

Endogenous MOV10 inhibits the retrotransposition of endogenous retroelements but not the replication of exogenous retroviruses

Science.gov (United States)

2012-01-01

Background The identification of cellular factors that regulate the replication of exogenous viruses and endogenous mobile elements provides fundamental understanding of host-pathogen relationships. MOV10 is a superfamily 1 putative RNA helicase that controls the replication of several RNA viruses and whose homologs are necessary for the repression of endogenous mobile elements. Here, we employ both ectopic expression and gene knockdown approaches to analyse the role of human MOV10 in the replication of a panel of exogenous retroviruses and endogenous retroelements. Results MOV10 overexpression substantially decreased the production of infectious retrovirus particles, as well the propagation of LTR and non-LTR endogenous retroelements. Most significantly, RNAi-mediated silencing of endogenous MOV10 enhanced the replication of both LTR and non-LTR endogenous retroelements, but not the production of infectious retrovirus particles demonstrating that natural levels of MOV10 suppress retrotransposition, but have no impact on infection by exogenous retroviruses. Furthermore, functional studies showed that MOV10 is not necessary for miRNA or siRNA-mediated mRNA silencing. Conclusions We have identified novel specificity for human MOV10 in the control of retroelement replication and hypothesise that MOV10 may be a component of a cellular pathway or process that selectively regulates the replication of endogenous retroelements in somatic cells. PMID:22727223

Genomic organization, sequence divergence, and recombination of feline immunodeficiency virus from lions in the wild

Science.gov (United States)

Pecon-Slattery, Jill; McCracken, Carrie L; Troyer, Jennifer L; VandeWoude, Sue; Roelke, Melody; Sondgeroth, Kerry; Winterbach, Christiaan; Winterbach, Hanlie; O'Brien, Stephen J

2008-01-01

Background Feline immunodeficiency virus (FIV) naturally infects multiple species of cat and is related to human immunodeficiency virus in humans. FIV infection causes AIDS-like disease and mortality in the domestic cat (Felis catus) and serves as a natural model for HIV infection in humans. In African lions (Panthera leo) and other exotic felid species, disease etiology introduced by FIV infection are less clear, but recent studies indicate that FIV causes moderate to severe CD4 depletion. Results In this study, comparative genomic methods are used to evaluate the full proviral genome of two geographically distinct FIV subtypes isolated from free-ranging lions. Genome organization of FIVPle subtype B (9891 bp) from lions in the Serengeti National Park in Tanzania and FIVPle subtype E (9899 bp) isolated from lions in the Okavango Delta in Botswana, both resemble FIV genome sequence from puma, Pallas cat and domestic cat across 5' LTR, gag, pol, vif, orfA, env, rev and 3'LTR regions. Comparative analyses of available full-length FIV consisting of subtypes A, B and C from FIVFca, Pallas cat FIVOma and two puma FIVPco subtypes A and B recapitulate the species-specific monophyly of FIV marked by high levels of genetic diversity both within and between species. Across all FIVPle gene regions except env, lion subtypes B and E are monophyletic, and marginally more similar to Pallas cat FIVOma than to other FIV. Sequence analyses indicate the SU and TM regions of env vary substantially between subtypes, with FIVPle subtype E more related to domestic cat FIVFca than to FIVPle subtype B and FIVOma likely reflecting recombination between strains in the wild. Conclusion This study demonstrates the necessity of whole-genome analysis to complement population/gene-based studies, which are of limited utility in uncovering complex events such as recombination that may lead to functional differences in virulence and pathogenicity. These full-length lion lentiviruses are integral to

Genomic organization, sequence divergence, and recombination of feline immunodeficiency virus from lions in the wild

Directory of Open Access Journals (Sweden)

Sondgeroth Kerry

2008-02-01

Full Text Available Abstract Background Feline immunodeficiency virus (FIV naturally infects multiple species of cat and is related to human immunodeficiency virus in humans. FIV infection causes AIDS-like disease and mortality in the domestic cat (Felis catus and serves as a natural model for HIV infection in humans. In African lions (Panthera leo and other exotic felid species, disease etiology introduced by FIV infection are less clear, but recent studies indicate that FIV causes moderate to severe CD4 depletion. Results In this study, comparative genomic methods are used to evaluate the full proviral genome of two geographically distinct FIV subtypes isolated from free-ranging lions. Genome organization of FIVPle subtype B (9891 bp from lions in the Serengeti National Park in Tanzania and FIVPle subtype E (9899 bp isolated from lions in the Okavango Delta in Botswana, both resemble FIV genome sequence from puma, Pallas cat and domestic cat across 5' LTR, gag, pol, vif, orfA, env, rev and 3'LTR regions. Comparative analyses of available full-length FIV consisting of subtypes A, B and C from FIVFca, Pallas cat FIVOma and two puma FIVPco subtypes A and B recapitulate the species-specific monophyly of FIV marked by high levels of genetic diversity both within and between species. Across all FIVPle gene regions except env, lion subtypes B and E are monophyletic, and marginally more similar to Pallas cat FIVOma than to other FIV. Sequence analyses indicate the SU and TM regions of env vary substantially between subtypes, with FIVPle subtype E more related to domestic cat FIVFca than to FIVPle subtype B and FIVOma likely reflecting recombination between strains in the wild. Conclusion This study demonstrates the necessity of whole-genome analysis to complement population/gene-based studies, which are of limited utility in uncovering complex events such as recombination that may lead to functional differences in virulence and pathogenicity. These full-length lion

Defective human T-cell lymphotropic virus type I (HTLV-I) provirus in seronegative tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM) patients.

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Ramirez, E; Fernandez, J; Cartier, L; Villota, C; Rios, M

2003-02-01

Infection with human T-cell lymphotropic virus type I (HTLV-I) have been associated with the development of the tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM). We studied the presence of HTLV-I provirus in peripheral blood mononuclear cells (PBMC) from 72 Chilean patients with progressive spastic paraparesis by polymerase chain reaction: 32 seropositive and 40 seronegative cases. We amplified different genomic regions of HTLV-I using primers of 5' ltr, tax, env/tax, pX, pol and env genes. These genes were detected from all seropositive patients. The seronegative patients were negative with 5' ltr, pol, env, and pX primers. However, amplified product of tax and env/tax genes was detected from 16 and four seronegative patients, respectively. Three of them were positive with both genetic regions. The results of this study show that the complete HTLV-I provirus is found in 100% of seropositive cases. In seronegative cases, clinically very similar of seropositive cases, was found only tax gene in 42.5% (17/40) of patients. These results suggest the presence of a defective HTLV-I provirus in some seronegative patients with progressive spastic paraparesis, and suggest a pathogenic role of this truncate provirus for a group of TSP/HAM.

GABBR1 has a HERV-W LTR in its regulatory region – a possible implication for schizophrenia

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Hegyi Hedi

2013-02-01

Full Text Available Abstract Schizophrenia is a complex disease with uncertain aetiology. We suggest GABBR1, GABA receptor B1 implicated in schizophrenia based on a HERV-W LTR in the regulatory region of GABBR1. Our hypothesis is supported by: (i GABBR1 is in the 6p22 genomic region most often implicated in schizophrenia; (ii microarray studies found that only presynaptic pathway-related genes, including GABA receptors, have altered expression in schizophrenic patients and (iii it explains how HERV-W elements, expressed in schizophrenia, play a role in the disease: by altering the expression of GABBR1 via a long terminal repeat that is also a regulatory element to GABBR1. Reviewers This paper was reviewed by Sandor Pongor and Martijn Huynen.

Identification of an internal ribosome entry segment in the 5' region of the mouse VL30 retrotransposon and its use in the development of retroviral vectors.

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López-Lastra, M; Ulrici, S; Gabus, C; Darlix, J L

1999-10-01

Mouse virus-like 30S RNAs (VL30m) constitute a family of retrotransposons, present at 100 to 200 copies, dispersed in the mouse genome. They display little sequence homology to Moloney murine leukemia virus (MoMLV), do not encode virus-like proteins, and have not been implicated in retroviral carcinogenesis. However, VL30 RNAs are efficiently packaged into MLV particles that are propagated in cell culture. In this study, we addressed whether the 5' region of VL30m could replace the 5' leader of MoMLV functionally in a recombinant vector construct. Our data confirm that the putative packaging sequence of VL30 is located within the 5' region (nucleotides 362 to 1149 with respect to the cap structure) and that it can replace the packaging sequence of MoMLV. We also show that VL30m contains an internal ribosome entry segment (IRES) in the 5' region, as do MoMLV, Friend murine leukemia virus, Harvey murine sarcoma virus, and avian reticuloendotheliosis virus type A. Our data show that both the packaging and IRES functions of the 5' region of VL30m RNA can be efficiently used to develop retrotransposon-based vectors.

Influence of cAMP on reporter bioassays for dioxin and dioxin-like compounds

International Nuclear Information System (INIS)

Kasai, Ayumi; Yao, Jian; Yamauchi, Kozue; Hiramatsu, Nobuhiko; Hayakawa, Kunihiro; Meng, Yiman; Maeda, Shuichiro; Kitamura, Masanori

2006-01-01

In reporter assays for detection of dioxins, the dioxin-responsive element (DRE) is generally used as a sensor sequence. In several systems, the CYP1A1 promoter containing DREs (DRE cyp ) is inserted into a part of the long terminal repeat of mouse mammary tumor virus (LTR MMTV ) to improve sensitivity of assays. We found that DRE cyp -LTR MMTV responds not only to dioxins and dioxin-like compounds but also to forskolin, a cAMP-elevating agent. This effect was dose-dependent and reproduced by other cAMP-elevating agents including 8-bromo-cAMP and 3-isobutyl-methylxanthine. The cAMP response element (CRE) and CRE-like sequences were absent in DRE cyp -LTR MMTV and not involved in this process. In contrast to the effect of dioxin, the activation of DRE cyp -LTR MMTV by cAMP was independent of the aryl hydrocarbon receptor (AhR), a ligand-dependent transcription factor for DRE. Furthermore, neither DRE cyp , LTR MMTV nor the consensus sequence of DRE alone was activated in response to cAMP. These data elucidated for the first time that the combination of DRE cyp with LTR MMTV causes a peculiar response to cAMP and suggested that use of AhR antagonists is essential to exclude false-positive responses of DRE cyp -LTR MMTV -based bioassays for detection and quantification of dioxins and dioxin-like compounds

Genetic characterization of human T-cell lymphotropic virus type 1 in Mozambique: transcontinental lineages drive the HTLV-1 endemic.

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Ana Carolina P Vicente

2011-04-01

Full Text Available Human T-Cell Lymphotropic Virus Type 1 (HTLV-1 is the etiological agent of adult T-cell leukemia (ATL and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP. It has been estimated that 10-20 million people are infected worldwide, but no successful treatment is available. Recently, the epidemiology of this virus was addressed in blood donors from Maputo, showing rates from 0.9 to 1.2%. However, the origin and impact of HTLV endemic in this population is unknown.To assess the HTLV-1 molecular epidemiology in Mozambique and to investigate their relationship with HTLV-1 lineages circulating worldwide.Blood donors and HIV patients were screened for HTLV antibodies by using enzyme immunoassay, followed by Western Blot. PCR and sequencing of HTLV-1 LTR region were applied and genetic HTLV-1 subtypes were assigned by the neighbor-joining method. The mean genetic distance of Mozambican HTLV-1 lineages among the genetic clusters were determined. Human mitochondrial (mt DNA analysis was performed and individuals classified in mtDNA haplogroups.LTR HTLV-1 analysis demonstrated that all isolates belong to the Transcontinental subgroup of the Cosmopolitan subtype. Mozambican HTLV-1 sequences had a high inter-strain genetic distance, reflecting in three major clusters. One cluster is associated with the South Africa sequences, one is related with Middle East and India strains and the third is a specific Mozambican cluster. Interestingly, 83.3% of HIV/HTLV-1 co-infection was observed in the Mozambican cluster. The human mtDNA haplotypes revealed that all belong to the African macrohaplogroup L with frequencies representatives of the country.The Mozambican HTLV-1 genetic diversity detected in this study reveals that although the strains belong to the most prevalent and worldwide distributed Transcontinental subgroup of the Cosmopolitan subtype, there is a high HTLV diversity that could be correlated with at least 3 different HTLV-1 introductions

Human T-lymphotropic virus type 1 Tax protein complexes with P-TEFb and competes for Brd4 and 7SK snRNP/HEXIM1 binding.

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Cho, Won-Kyung; Jang, Moon Kyoo; Huang, Keven; Pise-Masison, Cynthia A; Brady, John N

2010-12-01

Positive transcription elongation factor b (P-TEFb) plays an important role in stimulating RNA polymerase II elongation for viral and cellular gene expression. P-TEFb is found in cells in either an active, low-molecular-weight (LMW) form or an inactive, high-molecular-weight (HMW) form. We report here that human T-lymphotropic virus type 1 (HTLV-1) Tax interacts with the cyclin T1 subunit of P-TEFb, forming a distinct Tax/P-TEFb LMW complex. We demonstrate that Tax can play a role in regulating the amount of HMW complex present in the cell by decreasing the binding of 7SK snRNP/HEXIM1 to P-TEFb. This is seen both in vitro using purified Tax protein and in vivo in cells transduced with Tax expression constructs. Further, we find that a peptide of cyclin T1 spanning the Tax binding domain inhibits the ability of Tax to disrupt HMW P-TEFb complexes. These results suggest that the direct interaction of Tax with cyclin T1 can dissociate P-TEFb from the P-TEFb/7SK snRNP/HEXIM1 complex for activation of the viral long terminal repeat (LTR). We also show that Tax competes with Brd4 for P-TEFb binding. Chromatin immunoprecipitation (ChIP) assays demonstrated that Brd4 and P-TEFb are associated with the basal HTLV-1 LTR, while Tax and P-TEFb are associated with the activated template. Furthermore, the knockdown of Brd4 by small interfering RNA (siRNA) activates the HTLV-1 LTR promoter, which results in an increase in viral expression and production. Our studies have identified Tax as a regulator of P-TEFb that is capable of affecting the balance between its association with the large inactive complex and the small active complex.

Transcriptionally active LTR retrotransposons in Eucalyptus genus are differentially expressed and insertionally polymorphic.

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Marcon, Helena Sanches; Domingues, Douglas Silva; Silva, Juliana Costa; Borges, Rafael Junqueira; Matioli, Fábio Filippi; Fontes, Marcos Roberto de Mattos; Marino, Celso Luis

2015-08-14

In Eucalyptus genus, studies on genome composition and transposable elements (TEs) are particularly scarce. Nearly half of the recently released Eucalyptus grandis genome is composed by retrotransposons and this data provides an important opportunity to understand TE dynamics in Eucalyptus genome and transcriptome. We characterized nine families of transcriptionally active LTR retrotransposons from Copia and Gypsy superfamilies in Eucalyptus grandis genome and we depicted genomic distribution and copy number in two Eucalyptus species. We also evaluated genomic polymorphism and transcriptional profile in three organs of five Eucalyptus species. We observed contrasting genomic and transcriptional behavior in the same family among different species. RLC_egMax_1 was the most prevalent family and RLC_egAngela_1 was the family with the lowest copy number. Most families of both superfamilies have their insertions occurring Eucalyptus species. Using EST analysis and qRT-PCRs, we observed transcriptional activity in several tissues and in all evaluated species. In some families, osmotic stress increases transcript values. Our strategy was successful in isolating transcriptionally active retrotransposons in Eucalyptus, and each family has a particular genomic and transcriptional pattern. Overall, our results show that retrotransposon activity have differentially affected genome and transcriptome among Eucalyptus species.

Persistence of attenuated HIV-1 rev alleles in an epidemiologically linked cohort of long-term survivors infected with nef-deleted virus

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Wesselingh Steven L

2007-07-01

Full Text Available Abstract Background The Sydney blood bank cohort (SBBC of long-term survivors consists of multiple individuals infected with nef-deleted, attenuated strains of human immunodeficiency virus type 1 (HIV-1. Although the cohort members have experienced differing clinical courses and now comprise slow progressors (SP as well as long-term nonprogressors (LTNP, longitudinal analysis of nef/long-terminal repeat (LTR sequences demonstrated convergent nef/LTR sequence evolution in SBBC SP and LTNP. Thus, the in vivo pathogenicity of attenuated HIV-1 strains harboured by SBBC members is dictated by factors other than nef/LTR. Therefore, to determine whether defects in other viral genes contribute to attenuation of these HIV-1 strains, we characterized dominant HIV-1 rev alleles that persisted in 4 SBBC subjects; C18, C64, C98 and D36. Results The ability of Rev derived from D36 and C64 to bind the Rev responsive element (RRE in RNA binding assays was reduced by approximately 90% compared to Rev derived from HIV-1NL4-3, C18 or C98. D36 Rev also had a 50–60% reduction in ability to express Rev-dependent reporter constructs in mammalian cells. In contrast, C64 Rev had only marginally decreased Rev function despite attenuated RRE binding. In D36 and C64, attenuated RRE binding was associated with rare amino acid changes at 3 highly conserved residues; Gln to Pro at position 74 immediately N-terminal to the Rev activation domain, and Val to Leu and Ser to Pro at positions 104 and 106 at the Rev C-terminus, respectively. In D36, reduced Rev function was mapped to an unusual 13 amino acid extension at the Rev C-terminus. Conclusion These findings provide new genetic and mechanistic insights important for Rev function, and suggest that Rev function, not Rev/RRE binding may be rate limiting for HIV-1 replication. In addition, attenuated rev alleles may contribute to viral attenuation and long-term survival of HIV-1 infection in a subset of SBBC members.

A transgenic model of transactivation by the Tax protein of HTLV-I.

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Bieberich, C J; King, C M; Tinkle, B T; Jay, G

1993-09-01

The human T-lymphotropic virus type I (HTLV-I) Tax protein is a transcriptional regulatory protein that has been suggested to play a causal role in the development of several HTLV-I-associated diseases. Tax regulates expression of its own LTR and of certain cellular promoters perhaps by usurping the function of the host transcriptional machinery. We have established a transgenic mouse model system to define the spectrum of tissues in vivo that are capable of supporting Tax-mediated transcriptional transactivation. Transgenic mice carrying the HTLV-I LTR driving expression of the Escherichia coli beta-galactosidase (beta gal) gene were generated, and this LTR-beta gal gene was transcriptionally inactive in all tissues. When LTR-beta gal mice were mated to transgenic mice carrying the same LTR driving expression of the HTLV-I tax gene, mice that carried both transgenes showed restricted expression of the beta gal reporter gene in several tissues including muscle, bone, salivary glands, skin, and nerve. In addition, a dramatic increase in the number of beta gal-expressing cells was seen in response to wounding. These observations provide direct evidence for viral transactivation in vivo, delimit the tissues capable of supporting that transactivation, and provide a model system to study the mechanism of gene regulation by Tax.

Identification of an Internal Ribosome Entry Segment in the 5′ Region of the Mouse VL30 Retrotransposon and Its Use in the Development of Retroviral Vectors

Science.gov (United States)

López-Lastra, Marcelo; Ulrici, Sandrine; Gabus, Caroline; Darlix, Jean-Luc

1999-01-01

Mouse virus-like 30S RNAs (VL30m) constitute a family of retrotransposons, present at 100 to 200 copies, dispersed in the mouse genome. They display little sequence homology to Moloney murine leukemia virus (MoMLV), do not encode virus-like proteins, and have not been implicated in retroviral carcinogenesis. However, VL30 RNAs are efficiently packaged into MLV particles that are propagated in cell culture. In this study, we addressed whether the 5′ region of VL30m could replace the 5′ leader of MoMLV functionally in a recombinant vector construct. Our data confirm that the putative packaging sequence of VL30 is located within the 5′ region (nucleotides 362 to 1149 with respect to the cap structure) and that it can replace the packaging sequence of MoMLV. We also show that VL30m contains an internal ribosome entry segment (IRES) in the 5′ region, as do MoMLV, Friend murine leukemia virus, Harvey murine sarcoma virus, and avian reticuloendotheliosis virus type A. Our data show that both the packaging and IRES functions of the 5′ region of VL30m RNA can be efficiently used to develop retrotransposon-based vectors. PMID:10482590

Inclusion of Moloney murine leukemia virus elements upstream of the transgene cassette in an E1-deleted adenovirus leads to an unusual genomic integration in epithelial cells

International Nuclear Information System (INIS)

Zheng Changyu; O'Connell, Brian C.; Baum, Bruce J.

2003-01-01

Classically, the 5' and 3' long terminal repeats (LTRs) are considered necessary but not sufficient for retroviral integration. Recently, we reported that inclusion of these and additional elements from Moloney murine leukemia virus (MoMLV) facilitated transgene integration, without retroviral integrase, when placed in an adenoviral context (AdLTR-luc vector) (Nat. Biotech. 18 (2000), 176; Biochem. Biophys. Res. Commun. 300 (2003), 115). To help understand this nonhomologous DNA recombination event, we constructed another vector, AdELP-luc, with 2.7 kb of MoMLV elements identically placed into an E1-deleted adenovirus type 5 backbone upstream of a luciferase cDNA reporter gene. Unlike AdLTR-luc, no MoMLV elements were placed downstream of the expression cassette. AdELP-luc readily infected epithelial cells in vitro. Southern hybridizations with DNA from cloned cells showed that disruption of the MoMLV sequences occurred. One cell clone, grown in vitro without any special selection medium for 9 months, exhibited stable vector integration and luciferase activity. Importantly, both Southern hybridization and FISH analyses showed that in addition to the MoMLV elements and expression cassette, substantial adenoviral sequence downstream of the luciferase cDNA was genomically integrated. These results suggest that the 2.7 kb of MoMLV sequence included in AdELP-luc have cis-acting functions and mediates an unusual integration event

The effect of antiretroviral intensification with dolutegravir on residual virus replication in HIV-infected individuals: a randomised, placebo-controlled, double-blind trial.

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Rasmussen, Thomas A; McMahon, James H; Chang, J Judy; Audsley, Jennifer; Rhodes, Ajantha; Tennakoon, Surekha; Dantanarayana, Ashanti; Spelman, Tim; Schmidt, Tina; Kent, Stephen J; Morcilla, Vincent; Palmer, Sarah; Elliott, Julian H; Lewin, Sharon R

2018-04-06

Whether ongoing virus replication occurs in HIV-infected individuals on antiretroviral therapy (ART) is unclear; therefore, whether residual virus replication is a barrier to achieving a cure for HIV is also unknown. We aimed to establish whether ART intensification with dolutegravir would reveal or affect residual virus replication in HIV-infected individuals on suppressive treatment. In this randomised, placebo-controlled, double-blind trial, we enrolled HIV-infected adults (aged 18 years and older) receiving combination ART (at least three agents) for at least 3 years from the Alfred Hospital and Melbourne Sexual Health Centre, Melbourne, VIC, Australia. Eligible participants had fewer than 50 copies per mL HIV-1 plasma RNA for more than 3 years and fewer than 20 copies per mL at screening and two CD4 counts higher than 350 cells per μL in the previous 24 months including screening. Participants were randomly assigned (1:1) to receive 50 mg oral dolutegravir or placebo once a day for 56 days in addition to background ART. Follow-up was done at days 1, 3, 7, 14, 28, 56, and 84. The primary outcome was the change from baseline in frequency of 2-long terminal repeat (2-LTR) circles in peripheral blood CD4 cells at day 7. This trial is registered with ClinicalTrials.gov, number NCT02500446. Between Sept 21, 2015, and Sept 19, 2016, 46 individuals were screened for inclusion. 40 were eligible for inclusion and were randomly assigned to the dolutegravir (n=21) or placebo group (n=19). All enrolled participants completed the study procedures and no individuals were lost to follow up. All participants were on suppressive ART with 12% receiving protease inhibitors and the others non-nucleoside reverse transcriptase inhibitors. Median 2-LTR circles fold-change from baseline to day 7 was -0·17 (IQR -0·90 to 0·90) in the dolutegravir group and -0·26 (-1·00 to 1·17) in the placebo group (p=0·17). The addition of dolutegravir to pre-existing ART regimens was safe and

The effects of 5-fluorouracil and doxorubicin on expression of human immunodeficiency virus type 1 long terminal repeat

International Nuclear Information System (INIS)

Panozzo, J.; Akan, E.; Griffiths, T.D.

1996-01-01

Previous work by many groups has documented induction of the HIV-LTR following exposure of cells to ultraviolet light and other DNA damaging agents. Our experiments set out to determine the relative activation or repression of the HIV-LTR in response to two classes of chemotherapeutic agents: Doxorubicin is a DNA-damage inducing agent, and 5-fluorouracil has an antimetabolic mode of action. Using HeLa cells stably transfected with a construct in which HIV-LTR drives expression of the chloramphenicol acetyl transferase reporter gene, we demonstrated an up to 10-fold induction following doxorubicin treatment in 24 h post-treatment. This induction was repressed by treatment with salicylic acid, suggesting a role for prostaglandin/cyclo-oxygenase pathways and/or NFKB in the inductive response. Induction by 5-fluorouracil, in contrast, was more modest (two-fold at most) though it was consistently elevated over controls

Effects of integration and replication on transcription of the HIV-1 long terminal repeat

NARCIS (Netherlands)

Jeang, K. T.; Berkhout, B.; Dropulic, B.

1993-01-01

The activity of a promoter is influenced by chromosomal and cell cycle/replication context. We analyzed the influences of integration and replication on transcription of the human immunodeficiency virus (HIV)-1 long terminal repeat (LTR). We found that one requirement for Tat trans-activated

Tat-dependent repression of human immunodeficiency virus type 1 long terminal repeat promoter activity by fusion of cellular transcription factors

International Nuclear Information System (INIS)

Zhao Cunyou; Chen Yali; Park, Jiyoung; Kim, Jae Bum; Tang Hong

2004-01-01

Transcription initiation from HIV-1 long terminal repeat (LTR) promoter requires the virally encoded transactivator, Tat, and several cellular co-factors to accomplish the Tat-dependent processive transcription elongation. Individual cellular transcription activators, LBP-1b and Oct-1, on the other hand, have been shown to inhibit LTR promoter activities probably via competitive binding against TFIID to the TATA-box in LTR promoter. To explore the genetic interference strategies against the viral replication, we took advantage of the existence of the bipartite DNA binding domains and the repression domains of LBP-1b and Oct-1 factors to generate a chimeric transcription repressor. Our results indicated that the fusion protein of LBP-1b and Oct-1 exhibited higher DNA binding affinity to the viral promoter than the individual factors, and little interference with the host cell gene expression due to its anticipated rare cognate DNA sites in the host cell genome. Moreover, the chimera exerted increased Tat-dependent repression of transcription initiation at the LTR promoter both in vitro and in vivo compared to LBP-1b, Oct-1 or combination of LBP-1b and Oct-1. These results might provide the lead in generating a therapeutic reagent useful to suppress HIV-1 replication

Sub-nucleocapsid nanoparticles: a nasal vaccine against respiratory syncytial virus.

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Xavier Roux

Full Text Available BACKGROUND: Bronchiolitis caused by the respiratory syncytial virus (RSV in infants less than two years old is a growing public health concern worldwide, and there is currently no safe and effective vaccine. A major component of RSV nucleocapsid, the nucleoprotein (N, has been so far poorly explored as a potential vaccine antigen, even though it is a target of protective anti-viral T cell responses and is remarkably conserved between human RSV A and B serotypes. We recently reported a method to produce recombinant N assembling in homogenous rings composed of 10-11 N subunits enclosing a bacterial RNA. These nanoparticles were named sub-nucleocapsid ring structure (N SRS. METHODOLOGY AND PRINCIPAL FINDINGS: The vaccine potential of N SRS was evaluated in a well-characterized and widely acknowledged mouse model of RSV infection. BALB/c adult mice were immunized intranasally with N SRS adjuvanted with the detoxified E. coli enterotoxin LT(R192G. Upon RSV challenge, vaccinated mice were largely protected against virus replication in the lungs, with a mild inflammatory lymphocytic and neutrophilic reaction in their airways. Mucosal immunization with N SRS elicited strong local and systemic immunity characterized by high titers of IgG1, IgG2a and IgA anti-N antibodies, antigen-specific CD8(+ T cells and IFN-gamma-producing CD4(+ T cells. CONCLUSIONS/SIGNIFICANCE: This is the first report of using nanoparticles formed by the recombinant nucleocapsid protein as an efficient and safe intra-nasal vaccine against RSV.

Development of neurologic diseases in a patient with primate T lymphotropic virus type 1 (PTLV-1).

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Enose-Akahata, Yoshimi; Caruso, Breanna; Haner, Benjamin; Charlip, Emily; Nair, Govind; Massoud, Raya; Billioux, Bridgette J; Ohayon, Joan; Switzer, William M; Jacobson, Steven

2016-08-12

Virus transmission from various wild and domestic animals contributes to an increased risk of emerging infectious diseases in human populations. HTLV-1 is a human retrovirus associated with acute T-cell leukemia and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HTLV-1 originated from ancient zoonotic transmission from nonhuman primates, although cases of zoonotic infections continue to occur. Similar to HTLV-1, the simian counterpart, STLV-1, causes chronic infection and leukemia and lymphoma in naturally infected monkeys, and combined are called primate T-lymphotropic viruses (PTLV-1). However, other clinical syndromes typically seen in humans such as a chronic progressive myelopathy have not been observed in nonhuman primates. Little is known about the development of neurologic and inflammatory diseases in human populations infected with STLV-1-like viruses following nonhuman primate exposure. We performed detailed laboratory analyses on an HTLV-1 seropositive patient with typical HAM/TSP who was born in Liberia and now resides in the United States. Using a novel droplet digital PCR for the detection of the HTLV-1 tax gene, the proviral load in PBMC and cerebrospinal fluid cells was 12.98 and 51.68 %, respectively; however, we observed a distinct difference in fluorescence amplitude of the positive droplet population suggesting possible mutations in proviral DNA. A complete PTLV-1 proviral genome was amplified from the patient's PBMC DNA using an overlapping PCR strategy. Phylogenetic analysis of the envelope and LTR sequences showed the virus was highly related to PTLV-1 from sooty mangabey monkeys (smm) and humans exposed via nonhuman primates in West Africa. These results demonstrate the patient is infected with a simian variant of PTLV-1, suggesting for the first time that PTLV-1smm infection in humans may be associated with a chronic progressive neurologic disease.

Endogenous Retrovirus ev21 Dose Not Recombine with ALV-J and Induces the Expression of ISGs in the Host.

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Feng, Min; Tan, Yan; Dai, Manman; Li, Yuanfang; Xie, Tingting; Li, Hongmei; Shi, Meiqing; Zhang, Xiquan

2016-01-01

Avian leukosis virus subgroup J (ALV-J) infection can cause tumors and immunosuppression. Endogenous viruses integrate into host genomes and can recombine with exogenous avian leukosis virus (ALV). In this study, we analyzed the interaction of endogenous retrovirus 21 ( ev21 ) with the ALV-J in late-feathering Chinese yellow chicken. Two ALV-J strains M180 and K243 were isolated from late-feathering and fast-feathering Chinese yellow chicken flocks, respectively. The env gene of the two strains showed 94.2-94.8% nucleotide identity with reference ALV-J strains. Compared with the env gene and the LTR of ev21 and M180, the nucleotide identity of LTR was 69.7% and env gene was 58.4%, respectively, especially the amino acid identity of env gene as low as 14.2%. Phylogenetic analysis of the nucleotide sequence of the env gene and the 3'LTR showed that M180 was closely related to ALV-J, and was located in a distinct group with ev21 in the phylogenetic tree. Using co-immunoprecipitation (co-IP), we next demonstrate that the envelope protein of ev21 does not interact with the M180 envelope protein. We further show that the envelope protein of ev21 cannot activate ALV-J LTR promoter activity using luciferase-reporter assays. qPCR and western blot analysis revealed that envelope protein of endogenous ev21 can facilitate the expression of PKR at 6h post ALV-J infection (hpi) and facilitate the expression of ISG12 and CH25H at 24 hpi. However, the expression of the env gene of M180 strain was not significantly at 6 and 24 hpi. We conclude that there is no evidence of recombination between endogenous retrovirus ev21 and ALV-J strain M180 in late-feathering Chinese yellow chicken, and envelope protein of ev21 can affect the expression of host ISGs, but appears not to influence the replication of ALV-J strain M180. This is the first report of interaction among the endogenous retrovirus ev21, ALV-J and the late-feathering chicken.

Transcriptional Modulation of Human Endogenous Retroviruses in Primary CD4+ T Cells Following Vorinostat Treatment

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Cory H. White

2018-04-01

Full Text Available The greatest obstacle to a cure for HIV is the provirus that integrates into the genome of the infected cell and persists despite antiretroviral therapy. A “shock and kill” approach has been proposed as a strategy for an HIV cure whereby drugs and compounds referred to as latency-reversing agents (LRAs are used to “shock” the silent provirus into active replication to permit “killing” by virus-induced pathology or immune recognition. The LRA most utilized to date in clinical trials has been the histone deacetylase (HDAC inhibitor—vorinostat. Potentially, pathological off-target effects of vorinostat may result from the activation of human endogenous retroviruses (HERVs, which share common ancestry with exogenous retroviruses including HIV. To explore the effects of HDAC inhibition on HERV transcription, an unbiased pharmacogenomics approach (total RNA-Seq was used to evaluate HERV expression following the exposure of primary CD4+ T cells to a high dose of vorinostat. Over 2,000 individual HERV elements were found to be significantly modulated by vorinostat, whereby elements belonging to the ERVL family (e.g., LTR16C and LTR33 were predominantly downregulated, in contrast to LTR12 elements of the HERV-9 family, which exhibited the greatest signal, with the upregulation of 140 distinct elements. The modulation of three different LTR12 elements by vorinostat was confirmed by droplet digital PCR along a dose–response curve. The monitoring of LTR12 expression during clinical trials with vorinostat may be indicated to assess the impact of this HERV on the human genome and host immunity.

LQG/LTR optimal attitude control of small flexible spacecraft using free-free boundary conditions

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Fulton, Joseph M.

Due to the volume and power limitations of a small satellite, careful consideration must be taken while designing an attitude control system for 3-axis stabilization. Placing redundancy in the system proves difficult and utilizing power hungry, high accuracy, active actuators is not a viable option. Thus, it is customary to find dependable, passive actuators used in conjunction with small scale active control components. This document describes the application of Elastic Memory Composite materials in the construction of a flexible spacecraft appendage, such as a gravity gradient boom. Assumed modes methods are used with Finite Element Modeling information to obtain the equations of motion for the system while assuming free-free boundary conditions. A discussion is provided to illustrate how cantilever mode shapes are not always the best assumption when modeling small flexible spacecraft. A key point of interest is first resonant modes may be needed in the system design plant in spite of these modes being greater than one order of magnitude in frequency when compared to the crossover frequency of the controller. LQG/LTR optimal control techniques are implemented to compute attitude control gains while controller robustness considerations determine appropriate reduced order controllers and which flexible modes to include in the design model. Key satellite designer concerns in the areas of computer processor sizing, material uncertainty impacts on the system model, and system performance variations resulting from appendage length modifications are addressed.

Interaction of the phospholipid scramblase 1 with HIV-1 Tat results in the repression of Tat-dependent transcription

International Nuclear Information System (INIS)

Kusano, Shuichi; Eizuru, Yoshito

2013-01-01

Highlights: •PLSCR1 specifically interacted with HIV-1 Tat in vitro and in vivo. •PLSCR1 repressed Tat-dependent transactivation of the HIV-1 LTR. •Suppression of PLSCR1 expression enhanced the levels of HIV-1 transcripts. •PLSCR1 reduced the nuclear localization of Tat. -- Abstract: Human phospholipid scramblase 1 (PLSCR1) is an interferon (IFN)-stimulated gene and possesses an IFN-mediated antiviral function. We show here that PLSCR1 directly interacts with human immunodeficiency virus type-1 (HIV-1) Tat. This interaction occurs both in vitro and in vivo through amino acids 160–250 of PLSCR1. Overexpression of PLSCR1 efficiently represses the Tat-dependent transactivation of the HIV-1 long terminal repeat (LTR) and reduces the nuclear translocation of Tat. In addition, shRNA-mediated suppression of endogenous PLSCR1 expression enhances the levels of gag mRNA in an HIV-1-infected T-cell line. These findings indicate that PLSCR1 negatively regulates the Tat-dependent transactivation of the HIV-1 LTR during HIV-1 infection

HIV-1 Promoter Single Nucleotide Polymorphisms Are Associated with Clinical Disease Severity.

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Michael R Nonnemacher

Full Text Available The large majority of human immunodeficiency virus type 1 (HIV-1 markers of disease progression/severity previously identified have been associated with alterations in host genetic and immune responses, with few studies focused on viral genetic markers correlate with changes in disease severity. This study presents a cross-sectional/longitudinal study of HIV-1 single nucleotide polymorphisms (SNPs contained within the viral promoter or long terminal repeat (LTR in patients within the Drexel Medicine CNS AIDS Research and Eradication Study (CARES Cohort. HIV-1 LTR SNPs were found to associate with the classical clinical disease parameters CD4+ T-cell count and log viral load. They were found in both defined and undefined transcription factor binding sites of the LTR. A novel SNP identified at position 108 in a known COUP (chicken ovalbumin upstream promoter/AP1 transcription factor binding site was significantly correlated with binding phenotypes that are potentially the underlying cause of the associated clinical outcome (increase in viral load and decrease in CD4+ T-cell count.

Mutated N-ras does not induce p19 arf in CO25 cell line | Saleh ...

African Journals Online (AJOL)

The mouse cell line (CO25) used in this study was transfected with a glucocorticoid inducible mutated human N-ras oncogene under transcriptional control of the steroid-sensitive promoter of the mouse mammary tumors virus long terminal repeat MMTV-LTR. This study was aimed to investigate the expression of p19arf and ...

Novel 3′-Processing Integrase Activity Assay by Real-Time PCR for Screening and Identification of HIV-1 Integrase Inhibitors

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Supachai Sakkhachornphop

2015-01-01

Full Text Available The 3′-end processing (3′P of each viral long terminal repeat (LTR during human immunodeficiency virus type-1 (HIV-1 integration is a vital step in the HIV life cycle. Blocking the 3′P using 3′P inhibitor has recently become an attractive strategy for HIV-1 therapeutic intervention. Recently, we have developed a novel real-time PCR based assay for the detection of 3′P activity in vitro. The methodology usually involves biotinylated HIV-1 LTR, HIV-1 integrase (IN, and specific primers and probe. In this novel assay, we designed the HIV-1 LTR substrate based on a sequence with a homology to HIV-1 LTR labeled at its 3′ end with biotin on the sense strand. Two nucleotides at the 3′ end were subsequently removed by IN activity. Only two nucleotides labeled biotin were captured on an avidin-coated tube; therefore, inhibiting the binding of primers and probe results in late signals in the real-time PCR. This novel assay has successfully detected both the 3′P activity of HIV-1 IN and the anti-IN activity by Raltegravir and sodium azide agent. This real-time PCR assay has been shown to be effective and inexpensive for a high-throughput screening of novel IN inhibitors.

Antiviral propierties of 5,5'-dithiobis-2-nitrobenzoic acid and bacitracin against T-tropic human immunodeficiency virus type 1

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Rodriguez-Padilla Cristina

2011-03-01

Full Text Available Abstract Bacitracin and the membrane-impermeant thiol reagent 5,5'-dithiobis-2-nitrobenzoic acid (DTNB are agents known to inhibit protein disulfide isomerase (PDI, a cell-surface protein critical in HIV-1 entry therefore they are fusion inhibitors (FI. Here we investigated the possibility that Bacitracin and or DTNB might have other antiviral activities besides FI. By means of residual activity assays, we found that both compounds showed antiviral activity only to viruses T-tropic HIV-1 strain. Cell-based fusion assays showed inhibition on HeLa-CD4-LTR-β-gal (CD4 and HL2/3 cells treated with Bacitracin, and DTNB with the latest compound we observed fusion inhibition on both cells but strikingly in HL2/3 cells (expressing Env indicating a possible activity on both, the cell membrane and the viral envelope. A time-of-addition experiment showed that both compounds act on HIV entry inhibition but DTNB also acts at late stages of the viral cycle. Lastly, we also found evidence of long-lasting host cell protection in vitro by DTNB, an important pharmacodynamic parameter for a topical microbicide against virus infection, hours after the extracellular drug was removed; this protection was not rendered by Bacitracin. These drugs proved to be leading compounds for further studies against HIV showing antiviral characteristics of interest.

Intranasal Administration of 2/6-Rotavirus-Like Particles with Mutant Escherichia coli Heat-Labile Toxin (LT-R192G) Induces Antibody-Secreting Cell Responses but Not Protective Immunity in Gnotobiotic Pigs

Science.gov (United States)

Yuan, Lijuan; Geyer, Annelise; Hodgins, Douglas C.; Fan, Zhiqian; Qian, Yuan; Chang, Kyeong-Ok; Crawford, Sue E.; Parreño, Viviana; Ward, Lucy A.; Estes, Mary K.; Conner, Margaret E.; Saif, Linda J.

2000-01-01

We investigated the immunogenicity of recombinant double-layered rotavirus-like particle (2/6-VLPs) vaccines derived from simian SA11 or human (VP6) Wa and bovine RF (VP2) rotavirus strains. The 2/6-VLPs were administered to gnotobiotic pigs intranasally (i.n.) with a mutant Escherichia coli heat-labile toxin, LT-R192G (mLT), as mucosal adjuvant. Pigs were challenged with virulent Wa (P1A[8],G1) human rotavirus at postinoculation day (PID) 21 (two-dose VLP regimen) or 28 (three-dose VLP regimen). In vivo antigen-activated antibody-secreting cells (ASC) (effector B cells) and in vitro antigen-reactivated ASC (derived from memory B cells) from intestinal and systemic lymphoid tissues (duodenum, ileum, mesenteric lymph nodes [MLN], spleen, peripheral blood lymphocytes [PBL], and bone marrow lymphocytes) collected at selected times were quantitated by enzyme-linked immunospot assays. Rotavirus-specific immunoglobulin M (IgM), IgA, and IgG ASC and memory B-cell responses were detected by PID 21 or 28 in intestinal and systemic lymphoid tissues after i.n. inoculation with two or three doses of 2/6-VLPs with or without mLT. Greater mean numbers of virus-specific ASC and memory B cells in all tissues prechallenge were induced in pigs inoculated with two doses of SA11 2/6-VLPs plus mLT compared to SA11 2/6-VLPs without mLT. After challenge, anamnestic IgA and IgG ASC and memory B-cell responses were detected in intestinal lymphoid tissues of all VLP-inoculated groups, but serum virus-neutralizing antibody titers were not significantly enhanced compared to the challenged controls. Pigs inoculated with Wa-RF 2/6-VLPs (with or without mLT) developed higher anamnestic IgA and IgG ASC responses in ileum after challenge compared to pigs inoculated with SA11 2/6-VLPs (with or without mLT). Three doses of SA 11 2/6-VLP plus mLT induced the highest mean numbers of IgG memory B cells in MLN, spleen, and PBL among all groups postchallenge. However, no significant protection against

Low Proviral Load is Associated with Indeterminate Western Blot Patterns in Human T-Cell Lymphotropic Virus Type 1 Infected Individuals: Could Punctual Mutations be Related?

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Camila Cánepa

2015-10-01

Full Text Available Background: indeterminate Western blot (WB patterns are a major concern for diagnosis of human T-cell lymphotropic virus type 1 (HTLV-1 infection, even in non-endemic areas. Objectives: (a to define the prevalence of indeterminate WB among different populations from Argentina; (b to evaluate if low proviral load (PVL is associated with indeterminate WB profiles; and (c to describe mutations in LTR and tax sequence of these cases. Results: Among 2031 samples, 294 were reactive by screening. Of them, 48 (16.3% were WB indeterminate and of those 15 (31.3% were PCR+. Quantitative real-time PCR (qPCR was performed to 52 HTLV-1+ samples, classified as Group 1 (G1: 25 WB+ samples from individuals with pathologies; Group 2 (G2: 18 WB+ samples from asymptomatic carriers (AC; and Group 3 (G3: 9 seroindeterminate samples from AC. Median PVL was 4.78, 2.38, and 0.15 HTLV-1 copies/100 PBMCs, respectively; a significant difference (p=0.003 was observed. Age and sex were associated with PVL in G1 and G2, respectively. Mutations in the distal and central regions of Tax Responsive Elements (TRE 1 and 2 of G3 were observed, though not associated with PVL.The 8403A>G mutation of the distal region, previously related to high PVL, was absent in G3 but present in 50% of WB+ samples (p = 0.03. Conclusions: indeterminateWBresults confirmed later as HTLV-1 positive may be associated with low PVL levels. Mutations in LTR and tax are described; their functional relevance remains to be determined.

Epidemiología genómica y paraparesia espástica tropical asociada a la infección por el virus linfotrópico humano de células T tipo 1 Genome epidemiology and tropical spastic paraparesis associated with human T-cell lymphotropic virus type 1

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Mercedes Salcedo-Cifuentes

2011-11-01

Full Text Available OBJETIVO: Caracterizar el ambiente genómico de las secuencias adyacentes al virus linfotrópico humano de células T tipo 1 (HTLV-1 en pacientes con paraparesia espástica tropical y mielopatía asociada a la infección con HTLV-1 (PET/MAH de diferentes regiones de Colombia y del Japón. MÉTODOS: Se enfrentaron 71 clones recombinantes con secuencias del genoma humano adyacentes al 5'-LTR de pacientes con PET/MAH, a las bases de datos del Genome Browser y del Gen-Bank. Se identificaron y analizaron estadísticamente 16 variables genómicas estructurales y composicionales mediante el programa informático R, versión 2.8.1, en una ventana de 0,5 Mb. RESULTADOS: El 43,0% de los provirus se localizaron en los cromosomas del grupo C; 74% de las secuencias se ubicaron en regiones teloméricas y subteloméricas (P OBJECTIVE: Characterize the genomic environment of the sequences adjacent to human T-cell lymphotropic virus type 1 (HTLV-1 in patients with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP in different regions of Colombia and Japan. METHODS: A total of 71 recombinant clones with human genome sequences adjacent to 5' LTR in patients with HAM/TSP were compared to the Genome Browser and GenBank databases. Sixteen structural and compositional genome variables were identified, and statistical analysis was conducted in the R computer program, version 2.8.1, in a 0.5 Mb window. RESULTS: A total of 43.0% of the proviruses were located in the group C chromosomes; 74% of the sequences were located in the telomeric and subtelomeric regions (P < 0.05. A cluster analysis was used to establish the hierarchical relations between the genome characteristics included in the study. The analysis of principal components identified the components that defined the preferred genome environments for proviral integration in cases of HAM/TSP. CONCLUSIONS: HTLV-1 was integrated more often in chromatin regions rich in CpG islands with a high density

Pathogenicity and rapid growth kinetics of feline immunodeficiency virus are linked to 3' elements.

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Jesse Thompson

Full Text Available Chimeric viruses constructed between a highly pathogenic Feline Immunodeficiency Virus isolate (FIV-C36 and a less pathogenic but neurotropic strain (FIV-PPR have been used to map viral genetic determinants of in vivo pathogenicity. Chimeric virus FIV-PCenv, which contains FIV-C36 genome from the 3' region of pol to upstream of the 3'LTR on an FIV-PPR backbone, was previously shown to be replication-competent in vivo, inducing altered CD4(+ T-cell and neutrophil profiles intermediate between parental strains following a delay in viral replication during initial infection. Examination of FIV-PCenv proviral sequences recovered at week 11 post-infection revealed two changes compared to initial viral inoculum; the most significant being arginine to histidine in the integrase region of Pol at residue 813 (R813H. Pooled plasma from the initial in vivo study was used to inoculate a second cohort of cats to determine whether similar virulence and kinetics could be established following primary infection. Viral replication kinetics and immunocyte profiles were monitored in blood, bone marrow, and saliva over a one-year period. Passaged FIV-PCenv again displayed intermediate phenotype between parental strains, but unlike primary experiments, the onset of acute viremia was not delayed. CD4/8 alterations were noted in all groups of animals, though significant changes from controls were delayed in FIV-PPR infected animals compared to FIV-C36 and FIV-PCenv. In vivo passage of FIV-PCenv increased replication-competence relative to the initial molecularly-cloned chimera in association with one adaptive nucleotide change in the 5' end of the genome relative to primary tissue culture inoculum, while mutations in the 3' end of the genome were not detected. The results are consistent with the interpretation that 3' elements contribute to heightened virulence of FIV-C36, and that integrase residue 813 plays an important role in facilitating successful in vivo

Dynamics of viral replication in blood and lymphoid tissues during SIVmac251 infection of macaques

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Mannioui Abdelkrim

2009-01-01

Full Text Available Abstract Background Extensive studies of primary infection are crucial to our understanding of the course of HIV disease. In SIV-infected macaques, a model closely mimicking HIV pathogenesis, we used a combination of three markers -- viral RNA, 2LTR circles and viral DNA -- to evaluate viral replication and dissemination simultaneously in blood, secondary lymphoid tissues, and the gut during primary and chronic infections. Subsequent viral compartmentalization in the main target cells of the virus in peripheral blood during the chronic phase of infection was evaluated by cell sorting and viral quantification with the three markers studied. Results The evolutions of viral RNA, 2LTR circles and DNA levels were correlated in a given tissue during primary and early chronic infection. The decrease in plasma viral load principally reflects a large decrease in viral replication in gut-associated lymphoid tissue (GALT, with viral RNA and DNA levels remaining stable in the spleen and peripheral lymph nodes. Later, during chronic infection, a progressive depletion of central memory CD4+ T cells from the peripheral blood was observed, accompanied by high levels of viral replication in the cells of this subtype. The virus was also found to replicate at this point in the infection in naive CD4+ T cells. Viral RNA was frequently detected in monocytes, but no SIV replication appeared to occur in these cells, as no viral DNA or 2LTR circles were detected. Conclusion We demonstrated the persistence of viral replication and dissemination, mostly in secondary lymphoid tissues, during primary and early chronic infection. During chronic infection, the central memory CD4+ T cells were the major site of viral replication in peripheral blood, but viral replication also occurred in naive CD4+ T cells. The role of monocytes seemed to be limited to carrying the virus as a cargo because there was an observed lack of replication in these cells. These data may have important

Quadruplex-forming sequences occupy discrete regions inside plant LTR retrotransposons

Czech Academy of Sciences Publication Activity Database

Lexa, M.; Kejnovský, Eduard; Šteflová, Pavlína; Konvalinová, H.; Vorlíčková, Michaela; Vyskot, Boris

2014-01-01

Roč. 42, č. 2 (2014), s. 968-978 ISSN 0305-1048 R&D Projects: GA ČR(CZ) GAP205/12/0466; GA ČR(CZ) GAP305/10/0930; GA ČR(CZ) GAP501/10/0102; GA ČR(CZ) GA522/09/0083; GA ČR GPP501/10/P483 Institutional support: RVO:68081707 Keywords : INTRAMOLECULAR DNA QUADRUPLEXES * VIRUS TYPE-1 RNA * CIRCULAR-DICHROISM Subject RIV: BO - Biophysics Impact factor: 9.112, year: 2014

Determinants of Genomic RNA Encapsidation in the Saccharomyces cerevisiae Long Terminal Repeat Retrotransposons Ty1 and Ty3

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Katarzyna Pachulska-Wieczorek

2016-07-01

Full Text Available Long-terminal repeat (LTR retrotransposons are transposable genetic elements that replicate intracellularly, and can be considered progenitors of retroviruses. Ty1 and Ty3 are the most extensively characterized LTR retrotransposons whose RNA genomes provide the template for both protein translation and genomic RNA that is packaged into virus-like particles (VLPs and reverse transcribed. Genomic RNAs are not divided into separate pools of translated and packaged RNAs, therefore their trafficking and packaging into VLPs requires an equilibrium between competing events. In this review, we focus on Ty1 and Ty3 genomic RNA trafficking and packaging as essential steps of retrotransposon propagation. We summarize the existing knowledge on genomic RNA sequences and structures essential to these processes, the role of Gag proteins in repression of genomic RNA translation, delivery to VLP assembly sites, and encapsidation.

Identification of Human T-lymphotropic Virus Type I (HTLV-I Subtypes Using Restrited Fragment Length Polymorphism in a Cohort of Asymptomatic Carriers and Patients with HTLV-I-associated Myelopathy/tropical Spastic Paraparesis from São Paulo, Brazil

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Segurado Aluisio AC

2002-01-01

Full Text Available Although human T-lymphotropic virus type I (HTLV-I exhibits high genetic stability, as compared to other RNA viruses and particularly to human immunodeficiency virus (HIV, genotypic subtypes of this human retrovirus have been characterized in isolates from diverse geographical areas. These are currently believed not to be associated with different pathogenetic outcomes of infection. The present study aimed at characterizing genotypic subtypes of viral isolates from 70 HTLV-I-infected individuals from São Paulo, Brazil, including 42 asymptomatic carriers and 28 patients with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP, using restricted fragment length polymorphism (RFLP analysis of long terminal repeat (LTR HTLV-I proviral DNA sequences. Peripheral blood mononuclear cell lysates were amplified by nested polymerase chain reaction (PCR and amplicons submitted to enzymatic digestion using a panel of endonucleases. Among HTLV-I asymptomatic carriers, viral cosmopolitan subtypes A, B, C and E were identified in 73.8%, 7.1%, 7.1% and 12% of tested samples, respectively, whereas among HAM/TSP patients, cosmopolitan A (89.3%, cosmopolitan C (7.1% and cosmopolitan E (3.6% subtypes were detected. HTLV-I subtypes were not statistically significant associated with patients' clinical status. We also conclude that RFLP analysis is a suitable tool for descriptive studies on the molecular epidemiology of HTLV-I infections in our environment.

Hybridogenesis and a potential case of R2 non-LTR retrotransposon horizontal transmission in Bacillus stick insects (Insecta Phasmida).

Science.gov (United States)

Scavariello, Claudia; Luchetti, Andrea; Martoni, Francesco; Bonandin, Livia; Mantovani, Barbara

2017-02-06

Horizontal transfer (HT) is an event in which the genetic material is transferred from one species to another, even if distantly related, and it has been demonstrated as a possible essential part of the lifecycle of transposable elements (TEs). However, previous studies on the non-LTR R2 retrotransposon, a metazoan-wide distributed element, indicated its vertical transmission since the Radiata-Bilateria split. Here we present the first possible instances of R2 HT in stick insects of the genus Bacillus (Phasmida). Six R2 elements were characterized in the strictly bisexual subspecies B. grandii grandii, B. grandii benazzii and B. grandii maretimi and in the obligatory parthenogenetic taxon B. atticus. These elements were compared with those previously retrieved in the facultative parthenogenetic species B. rossius. Phylogenetic inconsistencies between element and host taxa, and age versus divergence analyses agree and support at least two HT events. These HT events can be explained by taking into consideration the complex Bacillus reproductive biology, which includes also hybridogenesis, gynogenesis and androgenesis. Through these non-canonical reproductive modes, R2 elements may have been transferred between Bacillus genomes. Our data suggest, therefore, a possible role of hybridization for TEs survival and the consequent reshaping of involved genomes.

Nucleotide sequence analysis of HTLV-I isolated from cerebrospinal fluid of a patient with TSP/HAM: comparison to other HTLV-I isolates.

Science.gov (United States)

Mukhopadhyaya, R; Sadaie, M R

1993-02-01

Human T-cell leukemia virus type I (HTLV-I) has been associated with adult T-cell leukemia/lymphoma and the chronic neurologic disorder tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM). To study the genetic structure of the virus associated with TSP/HAM, we have obtained and sequenced a partial genomic clone from an HTLV-I-positive cell line established from cerebrospinal fluid (CSF) of a Jamaican patient with TSP/HAM. This clone consisted of a 4.3-kb viral sequence containing the 5' long terminal repeat (LTR), gag, and N-terminal portion of the pol gene, with an overall 1.3% sequence variation resulting from mostly nucleotide substitutions, as compared to the prototype HTLV-I ATK-1. The gag and pol regions showed only 1.4% and 1.2% nucleotide variations, respectively. However, the U3 region of the LTR showed the highest sequence variation (3.6%), where several changes appear to be common among certain TSP/HAM isolates. Several of these changes reside within the 21-bp boundaries and the Tax-responsive element. It would be important to determine if the observed changes are sufficient to cause neurologic disorders similar to the murine leukemia virus system or simply reflect the divergent pool of HTLV-I from different geographic locations. At this time, we cannot rule out the possibility that the observed changes have either direct or indirect significance for the HTLV-I pathogenesis in TSP/HAM.

Ebola Virus and Marburg Virus

Science.gov (United States)

Ebola virus and Marburg virus Overview Ebola virus and Marburg virus are related viruses that cause hemorrhagic fevers — illnesses marked by severe bleeding (hemorrhage), organ failure and, in many ...

Functional Analysis of the Proto-oncogenes Septin9 and Nras

DEFF Research Database (Denmark)

Lassen, Louise Berkhoudt

filaments. Both SEPT7 and SEPT9 containing filaments were intensified under hypoxia in wild type cells compared to non-hypoxic cells despite their transcriptional downregulation. Due to earlier finding of Sept9 as a frequent integration site in T-cell lymphomas induced by retrovirus, the function of Sept9...... the murine leukemia virus Akv 1-99 in either sense or antisense direction. In addition a floxed PGK/Tn5 neomycin cassette was inserted. Expression analysis of Nras within knock in was used to study the effect of the LTR. If inserted before the endogenous promoter, the LTR in the antisense direction was found...... of Nras caused early postnatal lethality of the homozygous mice. A thorough analysis revealed that the homozygous mice suffered from granulocytosis and T-cell expansion within the spleen. The increased population of granulocytes was mainly immature, and subsequently a decrease of monocytes was found...

No Evidence of XMRV or MuLV Sequences in Prostate Cancer, Diffuse Large B-Cell Lymphoma, or the UK Blood Donor Population

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Mark James Robinson

2011-01-01

Full Text Available Xenotropic murine leukaemia virus-related virus (XMRV is a recently described retrovirus which has been claimed to infect humans and cause associated pathology. Initially identified in the US in patients with prostate cancer and subsequently in patients with chronic fatigue syndrome, doubt now exists that XMRV is a human pathogen. We studied the prevalence of genetic sequences of XMRV and related MuLV sequences in human prostate cancer, from B cell lymphoma patients and from UK blood donors. Nucleic acid was extracted from fresh prostate tissue biopsies, formalin-fixed paraffin-embedded (FFPE prostate tissue and FFPE B-cell lymphoma. The presence of XMRV-specific LTR or MuLV generic gag-like sequences was investigated by nested PCR. To control for mouse DNA contamination, a PCR that detected intracisternal A-type particle (IAP sequences was included. In addition, DNA and RNA were extracted from whole blood taken from UK blood donors and screened for XMRV sequences by real-time PCR. XMRV or MuLV-like sequences were not amplified from tissue samples. Occasionally MuLV gag and XMRV-LTR sequences were amplified from Indian prostate cancer samples, but were always detected in conjunction with contaminating murine genomic DNA. We found no evidence of XMRV or MuLV infection in the UK blood donors.

Correction of glucocerebrosidase deficiency after retroviral-mediated gene transfer into hematopoietic progenitor cells from patients with Gaucher disease

International Nuclear Information System (INIS)

Fink, J.K.; Correll, P.H.; Perry, L.K.; Brady, R.O.; Karlsson, S.

1990-01-01

Retroviral gene transfer has been used successfully to correct the glucocerebrosidase (GCase) deficiency in primary hematopoietic cells from patients with Gaucher disease. For this model of somatic gene therapy, the authors developed a high-titer, amphotropic retroviral vector designated NTG in which the human GCase gene was driven by the mutant polyoma virus enhancer/herpesvirus thymidine kinase gene (tk) promoter (Py + /Htk). NTG normalized GCase activity in transduced Gaucher fibroblasts and efficiently infected human monocytic and erythroleukemic cell lines. RNA blot-hybridization (Northern blot) analysis of these hemaptopoietic cell lines showed unexpectedly high-level expression from the Moloney murine leukemia virus long terminal repeat (Mo-MLV LTR) and levels of Py + /Htk enhancer/promoter-initiated human GCase RNA that approximated endogenous GCase RNA levels. Furthermore, NTG efficiently infected human hematopoietic progenitor cells. Detection of the provirus in approximately one-third of NTG-infected progenitor colonies that had not been selected in G418-containing medium indicates that relative resistance to G418 underestimated the actual gene transfer efficiency. Northern blot analysis of NTG-infected, progenitor-derived cells showed expression from both the Mo-MLV LTR and the Py + /Htk enhancer/promoter. NTG-transduced hematopoietic progenitor cells from patients with Gaucher disease generated progeny in which GCase activity has been normalized

Correction of glucocerebrosidase deficiency after retroviral-mediated gene transfer into hematopoietic progenitor cells from patients with Gaucher disease

Energy Technology Data Exchange (ETDEWEB)

Fink, J.K.; Correll, P.H.; Perry, L.K.; Brady, R.O.; Karlsson, S. (National Institutes of Health, Bethesda, MD (USA))

1990-03-01

Retroviral gene transfer has been used successfully to correct the glucocerebrosidase (GCase) deficiency in primary hematopoietic cells from patients with Gaucher disease. For this model of somatic gene therapy, the authors developed a high-titer, amphotropic retroviral vector designated NTG in which the human GCase gene was driven by the mutant polyoma virus enhancer/herpesvirus thymidine kinase gene (tk) promoter (Py{sup +}/Htk). NTG normalized GCase activity in transduced Gaucher fibroblasts and efficiently infected human monocytic and erythroleukemic cell lines. RNA blot-hybridization (Northern blot) analysis of these hemaptopoietic cell lines showed unexpectedly high-level expression from the Moloney murine leukemia virus long terminal repeat (Mo-MLV LTR) and levels of Py{sup +}/Htk enhancer/promoter-initiated human GCase RNA that approximated endogenous GCase RNA levels. Furthermore, NTG efficiently infected human hematopoietic progenitor cells. Detection of the provirus in approximately one-third of NTG-infected progenitor colonies that had not been selected in G418-containing medium indicates that relative resistance to G418 underestimated the actual gene transfer efficiency. Northern blot analysis of NTG-infected, progenitor-derived cells showed expression from both the Mo-MLV LTR and the Py{sup +}/Htk enhancer/promoter. NTG-transduced hematopoietic progenitor cells from patients with Gaucher disease generated progeny in which GCase activity has been normalized.

An Evolutionarily Young Polar Bear (Ursus maritimus) Endogenous Retrovirus Identified from Next Generation Sequence Data.

Science.gov (United States)

Tsangaras, Kyriakos; Mayer, Jens; Alquezar-Planas, David E; Greenwood, Alex D

2015-11-24

Transcriptome analysis of polar bear (Ursus maritimus) tissues identified sequences with similarity to Porcine Endogenous Retroviruses (PERV). Based on these sequences, four proviral copies and 15 solo long terminal repeats (LTRs) of a newly described endogenous retrovirus were characterized from the polar bear draft genome sequence. Closely related sequences were identified by PCR analysis of brown bear (Ursus arctos) and black bear (Ursus americanus) but were absent in non-Ursinae bear species. The virus was therefore designated UrsusERV. Two distinct groups of LTRs were observed including a recombinant ERV that contained one LTR belonging to each group indicating that genomic invasions by at least two UrsusERV variants have recently occurred. Age estimates based on proviral LTR divergence and conservation of integration sites among ursids suggest the viral group is only a few million years old. The youngest provirus was polar bear specific, had intact open reading frames (ORFs) and could potentially encode functional proteins. Phylogenetic analyses of UrsusERV consensus protein sequences suggest that it is part of a pig, gibbon and koala retrovirus clade. The young age estimates and lineage specificity of the virus suggests UrsusERV is a recent cross species transmission from an unknown reservoir and places the viral group among the youngest of ERVs identified in mammals.

An Evolutionarily Young Polar Bear (Ursus maritimus) Endogenous Retrovirus Identified from Next Generation Sequence Data

Science.gov (United States)

Tsangaras, Kyriakos; Mayer, Jens; Alquezar-Planas, David E.; Greenwood, Alex D.

2015-01-01

Transcriptome analysis of polar bear (Ursus maritimus) tissues identified sequences with similarity to Porcine Endogenous Retroviruses (PERV). Based on these sequences, four proviral copies and 15 solo long terminal repeats (LTRs) of a newly described endogenous retrovirus were characterized from the polar bear draft genome sequence. Closely related sequences were identified by PCR analysis of brown bear (Ursus arctos) and black bear (Ursus americanus) but were absent in non-Ursinae bear species. The virus was therefore designated UrsusERV. Two distinct groups of LTRs were observed including a recombinant ERV that contained one LTR belonging to each group indicating that genomic invasions by at least two UrsusERV variants have recently occurred. Age estimates based on proviral LTR divergence and conservation of integration sites among ursids suggest the viral group is only a few million years old. The youngest provirus was polar bear specific, had intact open reading frames (ORFs) and could potentially encode functional proteins. Phylogenetic analyses of UrsusERV consensus protein sequences suggest that it is part of a pig, gibbon and koala retrovirus clade. The young age estimates and lineage specificity of the virus suggests UrsusERV is a recent cross species transmission from an unknown reservoir and places the viral group among the youngest of ERVs identified in mammals. PMID:26610552

Not so bad after all: retroviruses and long terminal repeat retrotransposons as a source of new genes in vertebrates.

Science.gov (United States)

Naville, M; Warren, I A; Haftek-Terreau, Z; Chalopin, D; Brunet, F; Levin, P; Galiana, D; Volff, J-N

2016-04-01

Viruses and transposable elements, once considered as purely junk and selfish sequences, have repeatedly been used as a source of novel protein-coding genes during the evolution of most eukaryotic lineages, a phenomenon called 'molecular domestication'. This is exemplified perfectly in mammals and other vertebrates, where many genes derived from long terminal repeat (LTR) retroelements (retroviruses and LTR retrotransposons) have been identified through comparative genomics and functional analyses. In particular, genes derived from gag structural protein and envelope (env) genes, as well as from the integrase-coding and protease-coding sequences, have been identified in humans and other vertebrates. Retroelement-derived genes are involved in many important biological processes including placenta formation, cognitive functions in the brain and immunity against retroelements, as well as in cell proliferation, apoptosis and cancer. These observations support an important role of retroelement-derived genes in the evolution and diversification of the vertebrate lineage. Copyright © 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

HBZ and its roles in HTLV-1 oncogenesis

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Tiejun eZhao

2012-07-01

Full Text Available Human T-cell leukemia virus type 1 (HTLV-1 causes adult T-cell leukemia (ATL. The minus strand of HTLV-1 provirus encodes a bZIP protein donated as HTLV-1 bZIP factor (HBZ. Among the HTLV-1 regulatory and accessory genes, the tax and HBZ genes were thought to play critical roles in oncogenesis. However, HBZ is the only gene that remains intact and is consistently expressed in all ATL cases, while the tax gene is frequently inactivated by epigenetic modifications or deletion of the 5’LTR. HBZ gene promotes the proliferation of ATL cells through its mRNA form. Moreover, HBZ induces T-cell lymphoma and systemic inflammation in vivo. HBZ fulfills its functions mainly through regulating HTLV-1 5’LTR transcription and modulating a variety of cellular signaling pathways which are related with cell growth, immune response and T-cell differentiation. Taken together, the multiple functions of HBZ render its predominant function in leukemogenesis of ATL.

I-mfa domain proteins specifically interact with HTLV-1 Tax and repress its transactivating functions

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Kusano, Shuichi; Yoshimitsu, Makoto; Hachiman, Miho; Ikeda, Masanori

2015-01-01

The I-mfa domain proteins HIC (also known as MDFIC) and I-mfa (also known as MDFI) are candidate tumor suppressor genes that are involved in cellular and viral transcriptional regulation. Here, we show that HIC and I-mfa directly interact with human T-cell leukemia virus type-1 (HTLV-1) Tax protein in vitro. In addition, HIC and I-mfa repress Tax-dependent transactivation of an HTLV-1 long terminal repeat (LTR) reporter construct in COS-1, Jurkat and high-Tax-producing HTLV-1-infected T cells. HIC also interacts with Tax through its I-mfa domain in vivo and represses Tax-dependent transactivation of HTLV-1 LTR and NF-κB reporter constructs in an interaction-dependent manner. Furthermore, we show that HIC decreases the nuclear distribution and stimulates the proteasomal degradation of Tax. These data reveal that HIC specifically interacts with HTLV-1 Tax and negatively regulates Tax transactivational activity by altering its subcellular distribution and stability. - Highlights: • I-mfa domain proteins, HIC and I-mfa, specifically interact with HTLV-1 Tax. • HIC and I-mfa repress the Tax-dependent transactivation of HTLV-1 LTR. • HIC represses the Tax-dependent transactivation of NF-κΒ. • HIC decreases the nuclear distribution of Tax. • HIC stimulates the proteasomal degradation of Tax.

I-mfa domain proteins specifically interact with HTLV-1 Tax and repress its transactivating functions

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Kusano, Shuichi, E-mail: skusano@m2.kufm.kagoshima-u.ac.jp [Division of Persistent and Oncogenic Viruses, Center for Chronic Viral Diseases, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8544 (Japan); Yoshimitsu, Makoto; Hachiman, Miho [Division of Hematology and Immunology, Center for Chronic Viral Diseases, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8544 (Japan); Ikeda, Masanori [Division of Persistent and Oncogenic Viruses, Center for Chronic Viral Diseases, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8544 (Japan)

2015-12-15

The I-mfa domain proteins HIC (also known as MDFIC) and I-mfa (also known as MDFI) are candidate tumor suppressor genes that are involved in cellular and viral transcriptional regulation. Here, we show that HIC and I-mfa directly interact with human T-cell leukemia virus type-1 (HTLV-1) Tax protein in vitro. In addition, HIC and I-mfa repress Tax-dependent transactivation of an HTLV-1 long terminal repeat (LTR) reporter construct in COS-1, Jurkat and high-Tax-producing HTLV-1-infected T cells. HIC also interacts with Tax through its I-mfa domain in vivo and represses Tax-dependent transactivation of HTLV-1 LTR and NF-κB reporter constructs in an interaction-dependent manner. Furthermore, we show that HIC decreases the nuclear distribution and stimulates the proteasomal degradation of Tax. These data reveal that HIC specifically interacts with HTLV-1 Tax and negatively regulates Tax transactivational activity by altering its subcellular distribution and stability. - Highlights: • I-mfa domain proteins, HIC and I-mfa, specifically interact with HTLV-1 Tax. • HIC and I-mfa repress the Tax-dependent transactivation of HTLV-1 LTR. • HIC represses the Tax-dependent transactivation of NF-κΒ. • HIC decreases the nuclear distribution of Tax. • HIC stimulates the proteasomal degradation of Tax.

Characterization of a Full-Length Endogenous Beta-Retrovirus, EqERV-Beta1, in the Genome of the Horse (Equus caballus

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Antoinette C. van der Kuyl

2011-06-01

Full Text Available Information on endogenous retroviruses fixed in the horse (Equus caballus genome is scarce. The recent availability of a draft sequence of the horse genome enables the detection of such integrated viruses by similarity search. Using translated nucleotide fragments from gamma-, beta-, and delta-retroviral genera for initial searches, a full-length beta-retrovirus genome was retrieved from a horse chromosome 5 contig. The provirus, tentatively named EqERV-beta1 (for the first equine endogenous beta-retrovirus, was 10434 nucleotide (nt in length with the usual retroviral genome structure of 5’LTR-gag-pro-pol-env-3’LTR. The LTRs were 1361 nt long, and differed approximately 1% from each other, suggestive of a relatively recent integration. Coding sequences for gag, pro and pol were present in three different reading-frames, as common for beta-retroviruses, and the reading frames were completely open, except that the env gene was interrupted by a single stopcodon. No reading frame was apparent downstream of the env gene, suggesting that EqERV-beta1 does not encode a superantigen like mouse mammary tumor virus (MMTV. A second proviral genome of EqERV-beta1, with no stopcodon in env, is additionally integrated on chromosome 5 downstream of the first virus. Single EqERV-beta1 LTRs were abundantly present on all chromosomes except chromosome 24. Phylogenetically, EqERV-beta1 most closely resembles an unclassified retroviral sequence from cattle (Bos taurus, and the murine beta-retrovirus MMTV.

Virus-Vectored Influenza Virus Vaccines

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Tripp, Ralph A.; Tompkins, S. Mark

2014-01-01

Despite the availability of an inactivated vaccine that has been licensed for >50 years, the influenza virus continues to cause morbidity and mortality worldwide. Constant evolution of circulating influenza virus strains and the emergence of new strains diminishes the effectiveness of annual vaccines that rely on a match with circulating influenza strains. Thus, there is a continued need for new, efficacious vaccines conferring cross-clade protection to avoid the need for biannual reformulation of seasonal influenza vaccines. Recombinant virus-vectored vaccines are an appealing alternative to classical inactivated vaccines because virus vectors enable native expression of influenza antigens, even from virulent influenza viruses, while expressed in the context of the vector that can improve immunogenicity. In addition, a vectored vaccine often enables delivery of the vaccine to sites of inductive immunity such as the respiratory tract enabling protection from influenza virus infection. Moreover, the ability to readily manipulate virus vectors to produce novel influenza vaccines may provide the quickest path toward a universal vaccine protecting against all influenza viruses. This review will discuss experimental virus-vectored vaccines for use in humans, comparing them to licensed vaccines and the hurdles faced for licensure of these next-generation influenza virus vaccines. PMID:25105278

Globin haplotypes of human T-cell lymphotropic virus type I-infected individuals in Salvador, Bahia, Brazil, suggest a post-Columbian African origin of this virus.

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Alcantara, Luiz Carlos; Van Dooren, Sonia; Gonçalves, Marilda Souza; Kashima, Simone; Costa, Maria Cristina Ramos; Santos, Fred Luciano Neves; Bittencourt, Achilea Lisboa; Dourado, Inês; Filho, Antonio Andrade; Covas, Dimas Tadeu; Vandamme, Anne-Mieke; Galvão-Castro, Bernardo

2003-08-01

The city of Salvador, Bahia, Brazil, has sociodemographic characteristics similar to some African cities. Up to now, it has had the highest prevalence of human T-cell lymphotropic virus type I (HTLV-I) infection (1.74%) in the country. To investigate which strains of HTLV-I are circulating in Salvador, we studied isolates from 82 patients infected with HTLV-I: 19 from the general population, 21 from pregnant women, 16 from intravenous drug users, and 26 from patients and their family attending a neurologic clinic. Phylogenetic analysis from part of the LTR fragments showed that most of these isolates belonged to the Transcontinental subgroup of the Cosmopolitan subtype (HTLV-Ia). Only one sample from a pregnant woman was closely related to the Japanese subgroup, suggesting recent introduction of a Japanese HTLV-I lineage into Salvador. betaA-Globin haplotypes were examined in 34 infected individuals and found to be atypical, confirming the racial heterogeneity of this population. A total of 20 chromosomes were characterized as Central African Republic (CAR) haplotype (29.4%), 31 (45.6%) were characterized as Benin (BEN) haplotype, and 17 (25%) were characterized as Senegal (SEN) haplotype. Five patients' genotypes (14.7%) were CAR/CAR; 10 (29,4%), BEN/BEN; 9 (26.5%), CAR/BEN; 2 (5.9%), BEN/SEN; and 7 (20.6%), SEN/SEN. One patient's genotype (2.9%) was CAR/SEN. The betaA-globin haplotype distribution in Salvador is unusual compared with other Brazilian states. Our data support the hypothesis of multiple post-Columbian introductions of African HTLV-Ia strains in Salvador, Bahia, Brazil.

Assessment of genetic and epigenetic changes in virus-free garlic (Allium sativum L.) plants obtained by meristem culture followed by in vitro propagation.

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Gimenez, Magalí Diana; Yañez-Santos, Anahí Mara; Paz, Rosalía Cristina; Quiroga, Mariana Paola; Marfil, Carlos Federico; Conci, Vilma Cecilia; García-Lampasona, Sandra Claudia

2016-01-01

This is the first report assessing epigenetic variation in garlic. High genetic and epigenetic polymorphism during in vitro culture was detected.Sequencing of MSAP fragments revealed homology with ESTs. Garlic (Allium sativum) is a worldwide crop of economic importance susceptible to viral infections that can cause significant yield losses. Meristem tissue culture is the most employed method to sanitize elite cultivars.Often the virus-free garlic plants obtained are multiplied in vitro (micro propagation). However, it was reported that micro-propagation frequently produces somaclonal variation at the phenotypic level, which is an undesirable trait when breeders are seeking to maintain varietal stability. We employed amplification fragment length polymorphism and methylation sensitive amplified polymorphism (MSAP) methodologies to assess genetic and epigenetic modifications in two culture systems: virus-free plants obtained by meristem culture followed by in vitro multiplication and field culture. Our results suggest that garlic exhibits genetic and epigenetic polymorphism under field growing conditions. However, during in vitro culture system both kinds of polymorphisms intensify indicating that this system induces somaclonal variation. Furthermore, while genetic changes accumulated along the time of in vitro culture, epigenetic polymorphism reached the major variation at 6 months and then stabilize, being demethylation and CG methylation the principal conversions.Cloning and sequencing differentially methylated MSAP fragments allowed us to identify coding and unknown sequences of A. sativum, including sequences belonging to LTR Gypsy retrotransposons. Together, our results highlight that main changes occur in the initial 6 months of micro propagation. For the best of our knowledge, this is the first report on epigenetic assessment in garlic.

A Tat-conjugated Peptide Nucleic Acid Tat-PNA-DR Inhibits Hepatitis B Virus Replication In Vitro and In Vivo by Targeting LTR Direct Repeats of HBV RNA

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Zeng, Zhengyang; Han, Shisong; Hong, Wei; Lang, Yange; Li, Fangfang; Liu, Yongxiang; Li, Zeyong; Wu, Yingliang; Li, Wenxin; Zhang, Xianzheng; Cao, Zhijian

2016-01-01

Hepatitis B virus (HBV) infection is a major cause of chronic active hepatitis, cirrhosis, and primary hepatocellular carcinoma, all of which are severe threats to human health. However, current clinical therapies for HBV are limited by potential side effects, toxicity, and drug-resistance. In this study, a cell-penetrating peptide-conjugated peptide nucleic acid (PNA), Tat-PNA-DR, was designed to target the direct repeat (DR) sequences of HBV. Tat-PNA-DR effectively inhibited HBV replication in HepG2.2.15 cells. Its anti-HBV effect relied on the binding of Tat-PNA-DR to the DR, whereby it suppressed the translation of hepatitis B e antigen (HBeAg), HBsAg, HBV core, hepatitis B virus x protein, and HBV reverse transcriptase (RT) and the reverse transcription of the HBV genome. Furthermore, Tat-PNA-DR administered by intravenous injection efficiently cleared HBeAg and HBsAg in an acute hepatitis B mouse model. Importantly, it induced an 80% decline in HBV DNA in mouse serum, which was similar to the effect of the widely used clinical drug Lamivudine (3TC). Additionally, a long-term hydrodynamics HBV mouse model also demonstrated Tat-PNA-DR's antiviral effect. Interestingly, Tat-PNA-DR displayed low cytotoxicity, low mouse acute toxicity, low immunogenicity, and high serum stability. These data indicate that Tat-PNA-DR is a unique PNA and a promising drug candidate against HBV. PMID:26978579

A Tat-conjugated Peptide Nucleic Acid Tat-PNA-DR Inhibits Hepatitis B Virus Replication In Vitro and In Vivo by Targeting LTR Direct Repeats of HBV RNA

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Zhengyang Zeng

2016-01-01

Full Text Available Hepatitis B virus (HBV infection is a major cause of chronic active hepatitis, cirrhosis, and primary hepatocellular carcinoma, all of which are severe threats to human health. However, current clinical therapies for HBV are limited by potential side effects, toxicity, and drug-resistance. In this study, a cell-penetrating peptide-conjugated peptide nucleic acid (PNA, Tat-PNA-DR, was designed to target the direct repeat (DR sequences of HBV. Tat-PNA-DR effectively inhibited HBV replication in HepG2.2.15 cells. Its anti-HBV effect relied on the binding of Tat-PNA-DR to the DR, whereby it suppressed the translation of hepatitis B e antigen (HBeAg, HBsAg, HBV core, hepatitis B virus x protein, and HBV reverse transcriptase (RT and the reverse transcription of the HBV genome. Furthermore, Tat-PNA-DR administered by intravenous injection efficiently cleared HBeAg and HBsAg in an acute hepatitis B mouse model. Importantly, it induced an 80% decline in HBV DNA in mouse serum, which was similar to the effect of the widely used clinical drug Lamivudine (3TC. Additionally, a long-term hydrodynamics HBV mouse model also demonstrated Tat-PNA-DR's antiviral effect. Interestingly, Tat-PNA-DR displayed low cytotoxicity, low mouse acute toxicity, low immunogenicity, and high serum stability. These data indicate that Tat-PNA-DR is a unique PNA and a promising drug candidate against HBV.

HTLV-1 Tax mediated downregulation of miRNAs associated with chromatin remodeling factors in T cells with stably integrated viral promoter.

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Saifur Rahman

Full Text Available RNA interference (RNAi is a natural cellular mechanism to silence gene expression and is predominantly mediated by microRNAs (miRNAs that target messenger RNA. Viruses can manipulate the cellular processes necessary for their replication by targeting the host RNAi machinery. This study explores the effect of human T-cell leukemia virus type 1 (HTLV-1 transactivating protein Tax on the RNAi pathway in the context of a chromosomally integrated viral long terminal repeat (LTR using a CD4(+ T-cell line, Jurkat. Transcription factor profiling of the HTLV-1 LTR stably integrated T-cell clone transfected with Tax demonstrates increased activation of substrates and factors associated with chromatin remodeling complexes. Using a miRNA microarray and bioinformatics experimental approach, Tax was also shown to downregulate the expression of miRNAs associated with the translational regulation of factors required for chromatin remodeling. These observations were validated with selected miRNAs and an HTLV-1 infected T cells line, MT-2. miR-149 and miR-873 were found to be capable of directly targeting p300 and p/CAF, chromatin remodeling factors known to play critical role in HTLV-1 pathogenesis. Overall, these results are first in line establishing HTLV-1/Tax-miRNA-chromatin concept and open new avenues toward understanding retroviral latency and/or replication in a given cell type.

An Evolutionarily Young Polar Bear (Ursus maritimus Endogenous Retrovirus Identified from Next Generation Sequence Data

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Kyriakos Tsangaras

2015-11-01

Full Text Available Transcriptome analysis of polar bear (Ursus maritimus tissues identified sequences with similarity to Porcine Endogenous Retroviruses (PERV. Based on these sequences, four proviral copies and 15 solo long terminal repeats (LTRs of a newly described endogenous retrovirus were characterized from the polar bear draft genome sequence. Closely related sequences were identified by PCR analysis of brown bear (Ursus arctos and black bear (Ursus americanus but were absent in non-Ursinae bear species. The virus was therefore designated UrsusERV. Two distinct groups of LTRs were observed including a recombinant ERV that contained one LTR belonging to each group indicating that genomic invasions by at least two UrsusERV variants have recently occurred. Age estimates based on proviral LTR divergence and conservation of integration sites among ursids suggest the viral group is only a few million years old. The youngest provirus was polar bear specific, had intact open reading frames (ORFs and could potentially encode functional proteins. Phylogenetic analyses of UrsusERV consensus protein sequences suggest that it is part of a pig, gibbon and koala retrovirus clade. The young age estimates and lineage specificity of the virus suggests UrsusERV is a recent cross species transmission from an unknown reservoir and places the viral group among the youngest of ERVs identified in mammals.

Photosynthesis rates, growth, and ginsenoside contents of 2-yr-old Panax ginseng grown at different light transmission rates in a greenhouse.

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Jang, In-Bae; Lee, Dae-Young; Yu, Jin; Park, Hong-Woo; Mo, Hwang-Sung; Park, Kee-Choon; Hyun, Dong-Yun; Lee, Eung-Ho; Kim, Kee-Hong; Oh, Chang-Sik

2015-10-01

Ginseng is a semishade perennial plant cultivated in sloping, sun-shaded areas in Korea. Recently, owing to air-environmental stress and various fungal diseases, greenhouse cultivation has been suggested as an alternative. However, the optimal light transmission rate (LTR) in the greenhouse has not been established. The effect of LTR on photosynthesis rate, growth, and ginsenoside content of ginseng was examined by growing ginseng at the greenhouse under 6%, 9%, 13%, and 17% of LTR. The light-saturated net photosynthesis rate (A sat) and stomatal conductance (g s) of ginseng increased until the LTR reached 17% in the early stage of growth, whereas they dropped sharply owing to excessive leaf chlorosis at 17% LTR during the hottest summer period in August. Overall, 6-17% of LTR had no effect on the aerial part of plant length or diameter, whereas 17% and 13% of LRT induced the largest leaf area and the highest root weight, respectively. The total ginsenoside content of the ginseng leaves increased as the LTR increased, and the overall content of protopanaxatriol line ginsenosides was higher than that of protopanaxadiol line ginsenosides. The ginsenoside content of the ginseng roots also increased as the LTR increased, and the total ginsenoside content of ginseng grown at 17% LTR increased by 49.7% and 68.3% more than the ginseng grown at 6% LTR in August and final harvest, respectively. These results indicate that 13-17% of LTR should be recommended for greenhouse cultivation of ginseng.

Hijacking of the O-GlcNAcZYME complex by the HTLV-1 Tax oncoprotein facilitates viral transcription.

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Groussaud, Damien; Khair, Mostafa; Tollenaere, Armelle I; Waast, Laetitia; Kuo, Mei-Shiue; Mangeney, Marianne; Martella, Christophe; Fardini, Yann; Coste, Solène; Souidi, Mouloud; Benit, Laurence; Pique, Claudine; Issad, Tarik

2017-07-01

The viral Tax oncoprotein plays a key role in both Human T-cell lymphotropic virus type 1 (HTLV-1)-replication and HTLV-1-associated pathologies, notably adult T-cell leukemia. Tax governs the transcription from the viral 5'LTR, enhancing thereby its own expression, via the recruitment of dimers of phosphorylated CREB to cAMP-response elements located within the U3 region (vCRE). In addition to phosphorylation, CREB is also the target of O-GlcNAcylation, another reversible post-translational modification involved in a wide range of diseases, including cancers. O-GlcNAcylation consists in the addition of O-linked-N-acetylglucosamine (O-GlcNAc) on Serine or Threonine residues, a process controlled by two enzymes: O-GlcNAc transferase (OGT), which transfers O-GlcNAc on proteins, and O-GlcNAcase (OGA), which removes it. In this study, we investigated the status of O-GlcNAcylation enzymes in HTLV-1-transformed T cells. We found that OGA mRNA and protein expression levels are increased in HTLV-1-transformed T cells as compared to control T cell lines while OGT expression is unchanged. However, higher OGA production coincides with a reduction in OGA specific activity, showing that HTLV-1-transformed T cells produce high level of a less active form of OGA. Introducing Tax into HEK-293T cells or Tax-negative HTLV-1-transformed TL-om1 T cells is sufficient to inhibit OGA activity and increase total O-GlcNAcylation, without any change in OGT activity. Furthermore, Tax interacts with the OGT/OGA complex and inhibits the activity of OGT-bound OGA. Pharmacological inhibition of OGA increases CREB O-GlcNAcylation as well as HTLV-1-LTR transactivation by Tax and CREB recruitment to the LTR. Moreover, overexpression of wild-type CREB but not a CREB protein mutated on a previously described O-GlcNAcylation site enhances Tax-mediated LTR transactivation. Finally, both OGT and OGA are recruited to the LTR. These findings reveal the interplay between Tax and the O-GlcNAcylation pathway

MicroRNA-26a-mediated regulation of interleukin-2 expression in transformed avian lymphocyte lines

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Smith Lorraine P

2010-05-01

Full Text Available Abstract Background Micro(miRNAs are a class of small non-coding RNAs that play critical roles in the induction of various cancers, including lymphomas induced by oncogenic viruses. While some of the miRNAs are oncogenic, miRNAs such as miR-26a are consistently downregulated in a number of cancers, demonstrating their potential tumor suppressor functions. Global miRNA expression profiles of a number of virus-transformed avian lymphoma cell lines have shown downregulation of gga-miR-26a expression, irrespective of molecular mechanisms of transformation or the viral aetiology. The neoplastic transformation of lymphocytes by many viruses accompanies high levels of proliferative responses, mostly mediated through cytokines such as IL-2. Chicken IL-2 can modulate T-cell proliferation and cytotoxicity in vitro and in vivo and dysregulation of IL-2 expression is observed in diseases such as leukaemia. Results The expression levels of gga-miR-26a in chicken lymphoma cells transformed by 3 distinct avian oncogenic viruses, viz Marek's disease virus (MDV, avian leukosis virus (ALV and Reticuloendotheliosis virus (REV were consistently downregulated compared to the levels in the normal lymphocytes. This downregulation of miR-26a regardless of the viral etiology and molecular mechanisms of transformation was consistent with the tumor suppressor role of this miRNA. Notwithstanding this well-established role in cancer, we demonstrate the additional role of this miRNA in directly targeting chicken IL-2 through reporter and biochemical assays. The downregulation of miR-26a can relieve the suppressive effect of this miRNA on IL-2 expression. Conclusions We show that miR-26a is globally downregulated in a number of avian lymphoma cells irrespective of the mechanisms of transformation, reiterating the highly conserved tumor suppressor function of this miRNA. However, with the potential for directly targeting chicken IL-2, the downregulation of miR-26a in these

Nairobi sheep disease virus/Ganjam virus.

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M D, Baron; B, Holzer

2015-08-01

Nairobi sheep disease virus (NSDV) is a tick-borne virus which causes a severe disease in sheep and goats, and has been responsible for several outbreaks of disease in East Africa. The virus is also found in the Indian subcontinent, where it is known as Ganjam virus. The virus only spreads through the feeding of competent infected ticks, and is therefore limited in its geographic distribution by the distribution of those ticks, Rhipicephalus appendiculata in Africa and Haemaphysalis intermedia in India. Animals bred in endemic areas do not normally develop disease, and the impact is therefore primarily on animals being moved for trade or breeding purposes. The disease caused by NSDV has similarities to several other ruminant diseases, and laboratory diagnosis is necessary for confirmation. There are published methods for diagnosis based on polymerase chain reaction, for virus growth in cell culture and for other simple diagnostic tests, though none has been commercialised. There is no established vaccine against NSDV, although cell-culture attenuated strains have been developed which show promise and could be put into field trials if it were deemed necessary. The virus is closely related to Crimean-Congo haemorrhagic fever virus, and studies on NSDV may therefore be useful in understanding this important human pathogen.

Frequent and recent human acquisition of simian foamy viruses through apes' bites in central Africa.

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Edouard Betsem

2011-10-01

Full Text Available Human infection by simian foamy viruses (SFV can be acquired by persons occupationally exposed to non-human primates (NHP or in natural settings. This study aimed at getting better knowledge on SFV transmission dynamics, risk factors for such a zoonotic infection and, searching for intra-familial dissemination and the level of peripheral blood (proviral loads in infected individuals. We studied 1,321 people from the general adult population (mean age 49 yrs, 640 women and 681 men and 198 individuals, mostly men, all of whom had encountered a NHP with a resulting bite or scratch. All of these, either Pygmies (436 or Bantus (1085 live in villages in South Cameroon. A specific SFV Western blot was used and two nested PCRs (polymerase, and LTR were done on all the positive/borderline samples by serology. In the general population, 2/1,321 (0.2% persons were found to be infected. In the second group, 37/198 (18.6% persons were SFV positive. They were mostly infected by apes (37/39 FV (mainly gorilla. Infection by monkey FV was less frequent (2/39. The viral origin of the amplified sequences matched with the history reported by the hunters, most of which (83% are aged 20 to 40 years and acquired the infection during the last twenty years. The (proviral load in 33 individuals infected by a gorilla FV was quite low (<1 to 145 copies per 10(5 cells in the peripheral blood leucocytes. Of the 30 wives and 12 children from families of FV infected persons, only one woman was seropositive in WB without subsequent viral DNA amplification. We demonstrate a high level of recent transmission of SFVs to humans in natural settings specifically following severe gorilla bites during hunting activities. The virus was found to persist over several years, with low SFV loads in infected persons. Secondary transmission remains an open question.

SUN2 Modulates HIV-1 Infection and Latency through Association with Lamin A/C To Maintain the Repressive Chromatin.

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Sun, Wei-Wei; Jiao, Shi; Sun, Li; Zhou, Zhaocai; Jin, Xia; Wang, Jian-Hua

2018-05-01

The postintegrational latency of HIV-1 is characterized by reversible silencing of long terminal repeat (LTR)-driven transcription of the HIV genome. It is known that the formation of repressive chromatin at the 5'-LTR of HIV-1 proviral DNA impedes viral transcription by blocking the recruitment of positive transcription factors. How the repressive chromatin is formed and modulated during HIV-1 infection remains elusive. Elucidation of which chromatin reassembly factor mediates the reorganization of chromatin is likely to facilitate the understanding of the host's modulation of HIV-1 transcription and latency. Here we revealed that "Sad1 and UNC84 domain containing 2" (SUN2), an inner nuclear membrane protein, maintained the repressive chromatin and inhibited HIV LTR-driven transcription of proviral DNA through an association with lamin A/C. Specifically, lamin A/C tethered SUN2 to the nucleosomes 1 and 2 of the HIV-1 5'-LTR to block the initiation and elongation of HIV-1 transcription. SUN2 knockdown converted chromatin to an active form and thus enhanced the phosphorylation of RNA polymerase II and its recruitment to the 5'-LTR HIV-1 proviral DNA, leading to reactivation of HIV-1 from latency. Conversely, the exogenous factors such as tumor necrosis factor alpha (TNF-α) induced reactivation, and the replication of HIV-1 led to the disassociation between SUN2 and lamin A/C, suggesting that disruption of the association between SUN2 and lamin A/C to convert the repressive chromatin to the active form might be a prerequisite for the initiation of HIV-1 transcription and replication. Together, our findings indicate that SUN2 is a novel chromatin reassembly factor that helps to maintain chromatin in a repressive state and consequently inhibits HIV-1 transcription. IMPORTANCE Despite the successful use of scores of antiretroviral drugs, HIV latency poses a major impediment to virus eradication. Elucidation of the mechanism of latency facilitates the discovery of new

DIAGNOSTICS OF VIRUS PHYTOPATHOGENS FRUIT TREE PLUM POX VIRUS, PRUNUS NECROTIC RINGSPOT VIRUS AND PRUNUS DWARF VIRUS BY BIOLOGICAL AND MOLECULAR DIAGNOSTICS

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Július Rozák

2013-02-01

Full Text Available The aim of this study was to determine the incidence of viral phytopathogen Plum pox virus, Prunus necrotic ringspot virus and Prunus dwarf virus in selected localities of Slovakia and diagnose them using a molecular and biological methods. Forty samples of fruit trees of the genus Prunus, twenty samples from intensive plantings and twenty samples from wild subject were analysed. Biological diagnostic by using biological indicators Prunus persica cv. GF 305, Prunus serrulata cv. Schirofugen and molecular diagnostic by mRT-PCR were applied. Five samples with Plum pox virus were infected. The two samples positive for Prunus necrotic ringspot virus and one sample for Prunus dwarf virus were confirmed. The two samples were found to be infected with two viruses Prunus necrotic ringspot virus and Prunus dwarf virus. This work focuses on two techniques, their application to the diagnosis of stone fruit viruses and their routinely used for sanitary and certification programmes.

Oncogenic Viruses and Breast Cancer: Mouse Mammary Tumor Virus (MMTV, Bovine Leukemia Virus (BLV, Human Papilloma Virus (HPV, and Epstein–Barr Virus (EBV

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James S. Lawson

2018-01-01

Full Text Available BackgroundAlthough the risk factors for breast cancer are well established, namely female gender, early menarche and late menopause plus the protective influence of early pregnancy, the underlying causes of breast cancer remain unknown. The development of substantial recent evidence indicates that a handful of viruses may have a role in breast cancer. These viruses are mouse mammary tumor virus (MMTV, bovine leukemia virus (BLV, human papilloma viruses (HPVs, and Epstein–Barr virus (EBV-also known as human herpes virus type 4. Each of these viruses has documented oncogenic potential. The aim of this review is to inform the scientific and general community about this recent evidence.The evidenceMMTV and human breast cancer—the evidence is detailed and comprehensive but cannot be regarded as conclusive. BLV and human breast cancer—the evidence is limited. However, in view of the emerging information about BLV in human breast cancer, it is prudent to encourage the elimination of BLV in cattle, particularly in the dairy industry. HPVs and breast cancer—the evidence is substantial but not conclusive. The availability of effective preventive vaccines is a major advantage and their use should be encouraged. EBV and breast cancer—the evidence is also substantial but not conclusive. Currently, there are no practical means of either prevention or treatment. Although there is evidence of genetic predisposition, and cancer in general is a culmination of events, there is no evidence that inherited genetic traits are causal.ConclusionThe influence of oncogenic viruses is currently the major plausible hypothesis for a direct cause of human breast cancer.

Oncogenic Viruses and Breast Cancer: Mouse Mammary Tumor Virus (MMTV), Bovine Leukemia Virus (BLV), Human Papilloma Virus (HPV), and Epstein-Barr Virus (EBV).

Science.gov (United States)

Lawson, James S; Salmons, Brian; Glenn, Wendy K

2018-01-01

Although the risk factors for breast cancer are well established, namely female gender, early menarche and late menopause plus the protective influence of early pregnancy, the underlying causes of breast cancer remain unknown. The development of substantial recent evidence indicates that a handful of viruses may have a role in breast cancer. These viruses are mouse mammary tumor virus (MMTV), bovine leukemia virus (BLV), human papilloma viruses (HPVs), and Epstein-Barr virus (EBV-also known as human herpes virus type 4). Each of these viruses has documented oncogenic potential. The aim of this review is to inform the scientific and general community about this recent evidence. MMTV and human breast cancer-the evidence is detailed and comprehensive but cannot be regarded as conclusive. BLV and human breast cancer-the evidence is limited. However, in view of the emerging information about BLV in human breast cancer, it is prudent to encourage the elimination of BLV in cattle, particularly in the dairy industry. HPVs and breast cancer-the evidence is substantial but not conclusive. The availability of effective preventive vaccines is a major advantage and their use should be encouraged. EBV and breast cancer-the evidence is also substantial but not conclusive. Currently, there are no practical means of either prevention or treatment. Although there is evidence of genetic predisposition, and cancer in general is a culmination of events, there is no evidence that inherited genetic traits are causal. The influence of oncogenic viruses is currently the major plausible hypothesis for a direct cause of human breast cancer.

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

OpenAIRE

Savithri, HS; Murthy, MRN

1983-01-01

The amino acid sequences of the non-structural protein (molecular weight 35,000; 3a protein) from three plant viruses - cucumber mosaic, brome mosaic and alfalfa mosaic have been systematically compared using the partial genomic sequences for these three viruses already available. The 3a protein of cucumber mosaic virus has an amino acid sequence homology of 33.7% with the corresponding protein of brome mosaic virus. A similar protein from alfalfa mosaic virus has a homology of 18.2% and 14.2...

Protection of hematopoietic cells from O(6)-alkylation damage by O(6)-methylguanine DNA methyltransferase gene transfer: studies with different O(6)-alkylating agents and retroviral backbones.

Science.gov (United States)

Jansen, M; Bardenheuer, W; Sorg, U R; Seeber, S; Flasshove, M; Moritz, T

2001-07-01

Overexpression of O(6)-methylguanine DNA methyltransferase (MGMT) can protect hematopoietic cells from O(6)-alkylation damage. To identify possible clinical applications of this technology we compared the effect of MGMT gene transfer on the hematotoxicity induced by different O(6)-alkylating agents in clinical use: the chloroethylnitrosoureas ACNU, BCNU, CCNU and the tetrazine derivative temozolomide. In addition, various retroviral vectors expressing the MGMT-cDNA were investigated to identify optimal viral backbones for hematoprotection by MGMT expression. Protection from ACNU, BCNU, CCNU or temozolomide toxicity was evaluated utilizing a Moloney murine leukemia virus-based retroviral vector (N2/Zip-PGK-MGMT) to transduce primary murine bone marrow cells. Increased resistance in murine colony-forming units (CFU) was demonstrated for all four drugs. In comparison to mock-transduced controls, after transduction with N2/Zip-PGK-MGMT the IC50 for CFU increased on average 4.7-fold for ACNU, 2.5-fold for BCNU, 6.3-fold for CCNU and 1.5-fold for temozolomide. To study the effect of the retroviral backbone on hematoprotection various vectors expressing the human MGMT-cDNA from a murine embryonic sarcoma virus LTR (MSCV-MGMT) or a hybrid spleen focus-forming/murine embryonic sarcoma virus LTR (SF1-MGMT) were compared with the N2/Zip-PGK-MGMT vector. While all vectors increased resistance of transduced human CFU to ACNU, the SF1-MGMT construct was most efficient especially at high ACNU concentrations (8-12 microg/ml). Similar results were obtained for protection of murine high-proliferative-potential colony-forming cells. These data may help to optimize treatment design and retroviral constructs in future clinical studies aiming at hematoprotection by MGMT gene transfer.

Comparative analysis of chrysanthemum transcriptome in response to three RNA viruses: Cucumber mosaic virus, Tomato spotted wilt virus and Potato virus X.

Science.gov (United States)

Choi, Hoseong; Jo, Yeonhwa; Lian, Sen; Jo, Kyoung-Min; Chu, Hyosub; Yoon, Ju-Yeon; Choi, Seung-Kook; Kim, Kook-Hyung; Cho, Won Kyong

2015-06-01

The chrysanthemum is one of popular flowers in the world and a host for several viruses. So far, molecular interaction studies between the chrysanthemum and viruses are limited. In this study, we carried out a transcriptome analysis of chrysanthemum in response to three different viruses including Cucumber mosaic virus (CMV), Tomato spotted wilt virus (TSWV) and Potato virus X (PVX). A chrysanthemum 135K microarray derived from expressed sequence tags was successfully applied for the expression profiles of the chrysanthemum at early stage of virus infection. Finally, we identified a total of 125, 70 and 124 differentially expressed genes (DEGs) for CMV, TSWV and PVX, respectively. Many DEGs were virus specific; however, 33 DEGs were commonly regulated by three viruses. Gene ontology (GO) enrichment analysis identified a total of 132 GO terms, and of them, six GO terms related stress response and MCM complex were commonly identified for three viruses. Several genes functioning in stress response such as chitin response and ethylene mediated signaling pathway were up-regulated indicating their involvement in establishment of host immune system. In particular, TSWV infection significantly down-regulated genes related to DNA metabolic process including DNA replication, chromatin organization, histone modification and cytokinesis, and they are mostly targeted to nucleosome and MCM complex. Taken together, our comparative transcriptome analysis revealed several genes related to hormone mediated viral stress response and DNA modification. The identified chrysanthemums genes could be good candidates for further functional study associated with resistant to various plant viruses.

BFV activates the NF-κB pathway through its transactivator (BTas) to enhance viral transcription

International Nuclear Information System (INIS)

Wang Jian; Tan Juan; Zhang Xihui; Guo Hongyan; Zhang Qicheng; Guo Tingting; Geng Yunqi; Qiao Wentao

2010-01-01

Multiple families of viruses have evolved sophisticated strategies to regulate nuclear factor-κB (NF-κB) signaling, which plays a pivotal role in diverse cellular events, including virus-host interactions. In this study, we report that bovine foamy virus (BFV) is able to activate the NF-κB pathway through the action of its transactivator, BTas. Both cellular IKKβ and IκBα also participate in this activation. In addition, we demonstrate that BTas induces the processing of p100, which implies that BTas can activate NF-κB through a noncanonical pathway as well. Co-immunoprecipitation analysis shows that BTas interacts with IKK catalytic subunits (IKKα and IKKβ), which may be responsible for regulation of IKK kinase activity and persistent NF-κB activation. Furthermore, our results indicate that the level of BTas-mediated LTR transcription correlates with the activity of cellular NF-κB. Together, this study suggests that BFV activates the NF-κB pathway through BTas to enhance viral transcription.

Immune activation induces immortalization of HTLV-1 LTR-Tax transgenic CD4+ T cells

OpenAIRE

Swaims, Alison Y.; Khani, Francesca; Zhang, Yingyu; Roberts, Arthur I.; Devadas, Satish; Shi, Yufang; Rabson, Arnold B.

2010-01-01

Infection with the human T-cell leukemia virus-1 (HTLV-1) results in a variety of diseases including adult T-cell leukemia/lymphoma (ATL). Although the pathogenesis of these disorders is poorly understood, it involves complex interactions with the host immune system. Activation of infected T cells may play an important role in disease pathogenesis through induction of the oncogenic HTLV-1 Tax transactivator protein. To test this hypothesis, we employed transgenic mice in which Tax is regulate...

Regulation of human T-lymphotropic virus type I latency and reactivation by HBZ and Rex.

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Subha Philip

2014-04-01

Full Text Available Human T lymphotropic virus type I (HTLV-I infection is largely latent in infected persons. How HTLV-1 establishes latency and reactivates is unclear. Here we show that most HTLV-1-infected HeLa cells become senescent. By contrast, when NF-κB activity is blocked, senescence is averted, and infected cells continue to divide and chronically produce viral proteins. A small population of infected NF-κB-normal HeLa cells expresses low but detectable levels of Tax and Rex, albeit not Gag or Env. In these "latently" infected cells, HTLV-1 LTR trans-activation by Tax persists, but NF-κB trans-activation is attenuated due to inhibition by HBZ, the HTLV-1 antisense protein. Furthermore, Gag-Pol mRNA localizes primarily in the nuclei of these cells. Importantly, HBZ was found to inhibit Rex-mediated export of intron-containing mRNAs. Over-expression of Rex or shRNA-mediated silencing of HBZ led to viral reactivation. Importantly, strong NF-κB inhibition also reactivates HTLV-1. Hence, during HTLV-1 infection, when Tax/Rex expression is robust and dominant over HBZ, productive infection ensues with expression of structural proteins and NF-κB hyper-activation, which induces senescence. When Tax/Rex expression is muted and HBZ is dominant, latent infection is established with expression of regulatory (Tax/Rex/HBZ but not structural proteins. HBZ maintains viral latency by down-regulating Tax-induced NF-κB activation and senescence, and by inhibiting Rex-mediated expression of viral structural proteins.

Competitive virus assay method for titration of noncytopathogenic bovine viral diarrhea viruses (END⁺ and END⁻ viruses).

Science.gov (United States)

Muhsen, Mahmod; Ohi, Kota; Aoki, Hiroshi; Ikeda, Hidetoshi; Fukusho, Akio

2013-03-01

A new, reliable and secure virus assay method, named the competitive virus assay (CVA) method, has been established for the titration of bovine viral diarrhea viruses (BVDVs) that either show the exaltation of Newcastle disease virus (END) phenomenon or heterologous interference phenomenon (but not the END phenomenon). This method is based on the principle of (1) homologous interference between BVDVs, by using BVDV RK13/E(-) or BVDV RK13/E(+) strains as competitor virus, and (2) END phenomenon and heterologous interference, by using attenuated Newcastle disease virus (NDV) TCND strain as challenge virus. In titration of BVDV END(+) and BVDV END(-) viruses, no significant difference in estimated virus titer was observed between CVA and conventional methods. CVA method demonstrated comparable levels of sensitivity and accuracy as conventional END and interference methods, which require the use of a velogenic Miyadera strain of NDV and vesicular stomatitis virus (VSV), both of which are agents of high-risk diseases. As such, the CVA method is a safer alternative, with increased bio-safety and bio-containment, through avoidance of virulent strains that are commonly employed with conventional methods. Copyright © 2012 Elsevier B.V. All rights reserved.

Virus wars: using one virus to block the spread of another

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Matthew L. Paff

2016-06-01

Full Text Available The failure of traditional interventions to block and cure HIV infections has led to novel proposals that involve treating infections with therapeutic viruses–infectious viruses that specifically inhibit HIV propagation in the host. Early efforts in evaluating these proposals have been limited chiefly to mathematical models of dynamics, for lack of suitable empirical systems. Here we propose, develop and analyze an empirical system of a therapeutic virus that protects a host cell population against a lethal virus. The empirical system uses E. coli bacteria as the host cell population, an RNA phage as the lethal virus and a filamentous phage as the therapeutic virus. Basic dynamic properties are established for each virus alone and then together. Observed dynamics broadly agree with those predicted by a computer simulation model, although some differences are noted. Two cases of dynamics are contrasted, differing in whether the therapeutic virus is introduced before the lethal virus or after the lethal virus. The therapeutic virus increases in both cases but by different mechanisms. With the therapeutic virus introduced first, it spreads infectiously without any appreciable change in host dynamics. With the therapeutic virus introduced second, host abundance is depressed at the time therapy is applied; following an initial period of therapeutic virus spread by infection, the subsequent rise of protection is through reproduction by hosts already protected. This latter outcome is due to inheritance of the therapeutic virus state when the protected cell divides. Overall, the work establishes the feasibility and robustness to details of a viral interference using a therapeutic virus.

Zika virus disease

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Adel I Al-Afaleq

2017-01-01

Full Text Available The Zika virus is an arbovirus belonging to the virus family Flaviviridae. The virus was isolated in 1947 from a rhesus monkey in the Zika Forest of Uganda. The virus causes sporadic mild human infections in Africa and later in Asia. However, by 2007 a major shift in its infection pattern was noticed and thousands of human infections were reported in the State of Yap and Federated States of Micronesia. In the last 3 years, major outbreaks have continued to occur and the virus has spread to several Pacific and American countries. These outbreaks were mostly asymptomatic; however, there were more severe clinical signs associated with the infections. Those signs included microcephaly and Guillain–Barre syndrome. It is believed that various species of mosquitoes can biologically transmit the virus. However, Aedes aegypti is most widely associated with the Zika virus. Recently, new modes of virus transmission have been reported, including mother-to-fetus, sexual, blood transfusion, animal bites, laboratory exposure and breast milk. Differential diagnosis is very important as some other arboviruses such as yellow fever virus, West Nile virus, dengue virus, and chikungunya virus have similar clinical manifestations to the Zika virus infection as well as relating serologically to some of these viruses. Established laboratory diagnostic tests to detect the Zika virus are limited, with reverse transcription polymerase chain reaction being the most widely used test. Taking into consideration the quickness of the spread of infection, size of the infected population and change of the infection severity pattern, the Zika virus infection merits collective efforts on all levels to prevent and control the disease. Limited research work and data, concurrent infection with other arboviruses, involvement of biological vectors, mass crowd events, human and trade movements and lack of vaccines are some of the challenges that we face in our efforts to prevent and

Dengue virus receptor

OpenAIRE

Hidari, Kazuya I.P.J.; Suzuki, Takashi

2011-01-01

Dengue virus is an arthropod-borne virus transmitted by Aedes mosquitoes. Dengue virus causes fever and hemorrhagic disorders in humans and non-human primates. Direct interaction of the virus introduced by a mosquito bite with host receptor molecule(s) is crucial for virus propagation and the pathological progression of dengue diseases. Therefore, elucidation of the molecular mechanisms underlying the interaction between dengue virus and its receptor(s) in both humans and mosquitoes is essent...

ECHO virus

Science.gov (United States)

... page: //medlineplus.gov/ency/article/001340.htm ECHO virus To use the sharing features on this page, please enable JavaScript. Enteric cytopathic human orphan (ECHO) viruses are a group of viruses that can lead ...

FIV establishes a latent infection in feline peripheral blood CD4+ T lymphocytes in vivo during the asymptomatic phase of infection

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Murphy Brian

2012-02-01

Full Text Available Abstract Background Feline immunodeficiency virus (FIV is a lentivirus of cats that establishes a lifelong persistent infection with immunologic impairment. Results In an approximately 2 year-long experimental infection study, cats infected with a biological isolate of FIV clade C demonstrated undetectable plasma viral loads from 10 months post-infection onward. Viral DNA was detected in CD4+CD25+ and CD4+CD25- T cells isolated from infected cats whereas viral RNA was not detected at multiple time points during the early chronic phase of infection. Viral transcription could be reactivated in latently infected CD4+ T cells ex vivo as demonstrated by detectable FIV gag RNA and 2-long terminal repeat (LTR circle junctions. Viral LTR and gag sequences amplified from peripheral blood mononuclear cells during early and chronic stages of infection demonstrated minimal to no viral sequence variation. Conclusions Collectively, these findings are consistent with FIV latency in peripheral blood CD4+ T cells isolated from chronically infected cats. The ability to isolate latently FIV-infected CD4+ T lymphocytes from FIV-infected cats provides a platform for the study of in vivo mechanisms of lentiviral latency.

Hepatitis E virus coinfection with hepatotropic viruses in Egyptian children.

Science.gov (United States)

Zaki, Maysaa El Sayed; Salama, Osama Saad; Mansour, Fathy Awaad; Hossein, Shaimaa

2008-06-01

Major hepatotropic viruses continue to be important causes of acute viral hepatitis in developing countries. This work was carried out to detect the seroprevalence of hepatitis E virus (HEV) markers in children with acute viral hepatitis due to hepatotropic viruses (A, B and C) and non-A, non-B, non-C acute hepatitis, and to ascertain the influence of HEV superinfection in individuals infected with hepatitis viruses (A, B and C). We studied prospectively 162 children with sporadic acute hepatitis who reported to our hospital. Thirteen healthy controls were also included in the study. Laboratory investigations were performed, including complete liver function tests. Complete serological profiles for hepatitis viruses A, B, C and E were evaluated. HEV immunoglobulin G was detected with highest percentage among patients with hepatitis B (56.7%), followed by patients with hepatitis C virus (52.0%), hepatitis A virus (34.1%) and combined hepatitis B and C viruses (30.0%). The detection rate among patients with non-A, non-B, non-C hepatitis was 7.1%. HEV immunoglobulin M was found in 4.5% of hepatitis A virus patients and in 3.3% of hepatitis B patients. The prevalence of HEV immunoglobulin G and immunoglobulin M correlated with the levels of hepatic aspartate aminotransferase and alanine aminotransferase in patients with dual markers of infection with hepatitis E and other viruses compared to patients with acute hepatitis due to A and C viruses. HEV serological markers are common among children with acute viral hepatitis, especially from hepatitis C and B viruses. There may be increased sensitivity to HEV coinfection in association with hepatitis B and C infections. Dual infection with HEV and other hepatotropic viruses was associated with greater elevation of aspartate and alanine aminotransferases.

Phytophthora viruses.

Science.gov (United States)

Cai, Guohong; Hillman, Bradley I

2013-01-01

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. Copyright © 2013 Elsevier Inc. All rights reserved.

Viruses infecting reptiles.

Science.gov (United States)

Marschang, Rachel E

2011-11-01

A large number of viruses have been described in many different reptiles. These viruses include arboviruses that primarily infect mammals or birds as well as viruses that are specific for reptiles. Interest in arboviruses infecting reptiles has mainly focused on the role reptiles may play in the epidemiology of these viruses, especially over winter. Interest in reptile specific viruses has concentrated on both their importance for reptile medicine as well as virus taxonomy and evolution. The impact of many viral infections on reptile health is not known. Koch's postulates have only been fulfilled for a limited number of reptilian viruses. As diagnostic testing becomes more sensitive, multiple infections with various viruses and other infectious agents are also being detected. In most cases the interactions between these different agents are not known. This review provides an update on viruses described in reptiles, the animal species in which they have been detected, and what is known about their taxonomic positions.

Viruses Infecting Reptiles

Directory of Open Access Journals (Sweden)

Rachel E. Marschang

2011-11-01

Full Text Available A large number of viruses have been described in many different reptiles. These viruses include arboviruses that primarily infect mammals or birds as well as viruses that are specific for reptiles. Interest in arboviruses infecting reptiles has mainly focused on the role reptiles may play in the epidemiology of these viruses, especially over winter. Interest in reptile specific viruses has concentrated on both their importance for reptile medicine as well as virus taxonomy and evolution. The impact of many viral infections on reptile health is not known. Koch’s postulates have only been fulfilled for a limited number of reptilian viruses. As diagnostic testing becomes more sensitive, multiple infections with various viruses and other infectious agents are also being detected. In most cases the interactions between these different agents are not known. This review provides an update on viruses described in reptiles, the animal species in which they have been detected, and what is known about their taxonomic positions.

LTR real-time PCR for HIV-1 DNA quantitation in blood cells for early diagnosis in infants born to seropositive mothers treated in HAART area (ANRS CO 01).

Science.gov (United States)

Avettand-Fènoël, Véronique; Chaix, Marie-Laure; Blanche, Stéphane; Burgard, Marianne; Floch, Corinne; Toure, Kadidia; Allemon, Marie-Christine; Warszawski, Josiane; Rouzioux, Christine

2009-02-01

HIV-1 diagnosis in babies born to seropositive mothers is one of the challenges of HIV epidemics in children. A simple, rapid protocol was developed for quantifying HIV-1 DNA in whole blood samples and was used in the ANRS French pediatric cohort in conditions of prevention of mother-to-child transmission. A quantitative HIV-1 DNA protocol (LTR real-time PCR) requiring small blood volumes was developed. First, analytical reproducibility was evaluated on 172 samples. Results obtained on blood cell pellets and Ficoll-Hypaque separated mononuclear cells were compared in 48 adult HIV-1 samples. Second, the protocol was applied to HIV-1 diagnosis in infants in parallel with plasma HIV-RNA quantitation. This prospective study was performed in children born between May 2005 and April 2007 included in the ANRS cohort. The assay showed good reproducibility. The 95% detection cut-off value was 6 copies/PCR, that is, 40 copies/10(6) leukocytes. HIV-DNA levels in whole blood were highly correlated with those obtained after Ficoll-Hypaque separation (r = 0.900, P mothers have received HAART. (c) 2008 Wiley-Liss, Inc.

Characterization of uncultivable bat influenza virus using a replicative synthetic virus.

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Bin Zhou

2014-10-01

Full Text Available Bats harbor many viruses, which are periodically transmitted to humans resulting in outbreaks of disease (e.g., Ebola, SARS-CoV. Recently, influenza virus-like sequences were identified in bats; however, the viruses could not be cultured. This discovery aroused great interest in understanding the evolutionary history and pandemic potential of bat-influenza. Using synthetic genomics, we were unable to rescue the wild type bat virus, but could rescue a modified bat-influenza virus that had the HA and NA coding regions replaced with those of A/PR/8/1934 (H1N1. This modified bat-influenza virus replicated efficiently in vitro and in mice, resulting in severe disease. Additional studies using a bat-influenza virus that had the HA and NA of A/swine/Texas/4199-2/1998 (H3N2 showed that the PR8 HA and NA contributed to the pathogenicity in mice. Unlike other influenza viruses, engineering truncations hypothesized to reduce interferon antagonism into the NS1 protein didn't attenuate bat-influenza. In contrast, substitution of a putative virulence mutation from the bat-influenza PB2 significantly attenuated the virus in mice and introduction of a putative virulence mutation increased its pathogenicity. Mini-genome replication studies and virus reassortment experiments demonstrated that bat-influenza has very limited genetic and protein compatibility with Type A or Type B influenza viruses, yet it readily reassorts with another divergent bat-influenza virus, suggesting that the bat-influenza lineage may represent a new Genus/Species within the Orthomyxoviridae family. Collectively, our data indicate that the bat-influenza viruses recently identified are authentic viruses that pose little, if any, pandemic threat to humans; however, they provide new insights into the evolution and basic biology of influenza viruses.

Characterization of uncultivable bat influenza virus using a replicative synthetic virus.

Science.gov (United States)

Zhou, Bin; Ma, Jingjiao; Liu, Qinfang; Bawa, Bhupinder; Wang, Wei; Shabman, Reed S; Duff, Michael; Lee, Jinhwa; Lang, Yuekun; Cao, Nan; Nagy, Abdou; Lin, Xudong; Stockwell, Timothy B; Richt, Juergen A; Wentworth, David E; Ma, Wenjun

2014-10-01

Bats harbor many viruses, which are periodically transmitted to humans resulting in outbreaks of disease (e.g., Ebola, SARS-CoV). Recently, influenza virus-like sequences were identified in bats; however, the viruses could not be cultured. This discovery aroused great interest in understanding the evolutionary history and pandemic potential of bat-influenza. Using synthetic genomics, we were unable to rescue the wild type bat virus, but could rescue a modified bat-influenza virus that had the HA and NA coding regions replaced with those of A/PR/8/1934 (H1N1). This modified bat-influenza virus replicated efficiently in vitro and in mice, resulting in severe disease. Additional studies using a bat-influenza virus that had the HA and NA of A/swine/Texas/4199-2/1998 (H3N2) showed that the PR8 HA and NA contributed to the pathogenicity in mice. Unlike other influenza viruses, engineering truncations hypothesized to reduce interferon antagonism into the NS1 protein didn't attenuate bat-influenza. In contrast, substitution of a putative virulence mutation from the bat-influenza PB2 significantly attenuated the virus in mice and introduction of a putative virulence mutation increased its pathogenicity. Mini-genome replication studies and virus reassortment experiments demonstrated that bat-influenza has very limited genetic and protein compatibility with Type A or Type B influenza viruses, yet it readily reassorts with another divergent bat-influenza virus, suggesting that the bat-influenza lineage may represent a new Genus/Species within the Orthomyxoviridae family. Collectively, our data indicate that the bat-influenza viruses recently identified are authentic viruses that pose little, if any, pandemic threat to humans; however, they provide new insights into the evolution and basic biology of influenza viruses.

Discovery and analysis of an active long terminal repeat-retrotransposable element in Aspergillus oryzae.

Science.gov (United States)

Jie Jin, Feng; Hara, Seiichi; Sato, Atsushi; Koyama, Yasuji

2014-01-01

Wild-type Aspergillus oryzae RIB40 contains two copies of the AO090005001597 gene. We previously constructed A. oryzae RIB40 strain, RKuAF8B, with multiple chromosomal deletions, in which the AO090005001597 copy number was found to be increased significantly. Sequence analysis indicated that AO090005001597 is part of a putative 6,000-bp retrotransposable element, flanked by two long terminal repeats (LTRs) of 669 bp, with characteristics of retroviruses and retrotransposons, and thus designated AoLTR (A. oryzae LTR-retrotransposable element). AoLTR comprised putative reverse transcriptase, RNase H, and integrase domains. The deduced amino acid sequence alignment of AoLTR showed 94% overall identity with AFLAV, an A. flavus Tf1/sushi retrotransposon. Quantitative real-time RT-PCR showed that AoLTR gene expression was significantly increased in the RKuAF8B, in accordance with the increased copy number. Inverse PCR indicated that the full-length retrotransposable element was randomly integrated into multiple genomic locations. However, no obvious phenotypic changes were associated with the increased AoLTR gene copy number.

Prevalence of human immunodeficiency virus, hepatitis C virus ...

African Journals Online (AJOL)

Background. Human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV) and syphilis remain major infections around the world. In Angola, about 166 000 individuals are living with HIV, representing a prevalence of 1.98% in adults between 15 and 49 years of age. In a 2003 study in Luanda, 4.5% ...

Dose establishing a safety margin reduce local recurrence in subsegmental transarterial chemoembolization for small nodular hepatocellular carcinomas?

International Nuclear Information System (INIS)

Kang, Hyo Jin; Kim, Young Il; Kim, Hyo Cheol; Jae, Hwan Jun; Hur, Sae Beam; Chung, Jin Wook

2015-01-01

To test the hypothesis that a safety margin may affect local tumor recurrence (LTR) in subsegmental chemoembolization. In 101 patients with 128 hepatocellular carcinoma (HCC) nodules (1-3 cm in size and ≤ 3 in number), cone-beam CT-assisted subsegmental lipiodol chemoembolization was performed. Immediately thereafter, a non-contrast thin-section CT image was obtained to evaluate the presence or absence of intra-tumoral lipiodol uptake defect and safety margin. The effect of lipiodol uptake defect and safety margin on LTR was evaluated. Univariate and multivariate analyses were performed to indentify determinant factors of LTR. Of the 128 HCC nodules in 101 patients, 49 (38.3%) nodules in 40 patients showed LTR during follow-up period (median, 34.1 months). Cumulative 1- and 2-year LTR rates of nodules with lipiodol uptake defect (n = 27) and those without defect (n = 101) were 58.1% vs. 10.1% and 72.1% vs. 19.5%, respectively (p < 0.001). Among the 101 nodules without a defect, the 1- and 2-year cumulative LTR rates for nodules with complete safety margin (n = 52) and those with incomplete safety margin (n = 49) were 9.8% vs. 12.8% and 18.9% vs. 19.0% (p = 0.912). In multivariate analyses, ascites (p = 0.035), indistinct tumor margin on cone-beam CT (p = 0.039), heterogeneous lipiodol uptake (p = 0.023), and intra-tumoral lipiodol uptake defect (p < 0.001) were determinant factors of higher LTR. In lipiodol chemoembolization, the safety margin in completely lipiodolized nodule without defect will not affect LTR in small nodular HCCs

Epstein - Barr Virus

OpenAIRE

Štorkánová, Lenka

2011-01-01

Epstein-Barr virus Bachelor thesis summarizes the findings of Epstein-Barr virus (EBV), its general characteristics, transmission and spread of the virus, symptoms of disease and subsequent therapy and recovery. More specifically, it focuses on infectious mononucleosis, as well as more generally to other diseases, which the Epstein-Barr virus causes. It includes details of the vaccine against EB virus. There are the statistics on the incidence of infectious mononucleosis.

Emerging influenza viruses and the prospect of a universal influenza virus vaccine.

Science.gov (United States)

Krammer, Florian

2015-05-01

Influenza viruses cause annual seasonal epidemics and pandemics at irregular intervals. Several cases of human infections with avian and swine influenza viruses have been detected recently, warranting enhanced surveillance and the development of more effective countermeasures to address the pandemic potential of these viruses. The most effective countermeasure against influenza virus infection is the use of prophylactic vaccines. However, vaccines that are currently in use for seasonal influenza viruses have to be re-formulated and re-administered in a cumbersome process every year due to the antigenic drift of the virus. Furthermore, current seasonal vaccines are ineffective against novel pandemic strains. This paper reviews zoonotic influenza viruses with pandemic potential and technological advances towards better vaccines that induce broad and long lasting protection from influenza virus infection. Recent efforts have focused on the development of broadly protective/universal influenza virus vaccines that can provide immunity against drifted seasonal influenza virus strains but also against potential pandemic viruses. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Virus-host interaction in feline immunodeficiency virus (FIV) infection.

Science.gov (United States)

Taniwaki, Sueli Akemi; Figueiredo, Andreza Soriano; Araujo, João Pessoa

2013-12-01

Feline immunodeficiency virus (FIV) infection has been the focus of several studies because this virus exhibits genetic and pathogenic characteristics that are similar to those of the human immunodeficiency virus (HIV). FIV causes acquired immunodeficiency syndrome (AIDS) in cats, nevertheless, a large fraction of infected cats remain asymptomatic throughout life despite of persistent chronic infection. This slow disease progression may be due to the presence of factors that are involved in the natural resistance to infection and the immune response that is mounted by the animals, as well as due to the adaptation of the virus to the host. Therefore, the study of virus-host interaction is essential to the understanding of the different patterns of disease course and the virus persistence in the host, and to help with the development of effective vaccines and perhaps the cure of FIV and HIV infections. Copyright © 2013 Elsevier Ltd. All rights reserved.

Robust control technique for nuclear power plants

International Nuclear Information System (INIS)

Murphy, G.V.; Bailey, J.M.

1989-03-01

This report summarizes the linear quadratic Guassian (LQG) design technique with loop transfer recovery (LQG/LTR) for design of control systems. The concepts of return ratio, return difference, inverse return difference, and singular values are summarized. The LQG/LTR design technique allows the synthesis of a robust control system. To illustrate the LQG/LTR technique, a linearized model of a simple process has been chosen. The process has three state variables, one input, and one output. Three control system design methods are compared: LQG, LQG/LTR, and a proportional plus integral controller (PI). 7 refs., 20 figs., 6 tabs

Systematic analysis of protein identity between Zika virus and other arthropod-borne viruses.

Science.gov (United States)

Chang, Hsiao-Han; Huber, Roland G; Bond, Peter J; Grad, Yonatan H; Camerini, David; Maurer-Stroh, Sebastian; Lipsitch, Marc

2017-07-01

To analyse the proportions of protein identity between Zika virus and dengue, Japanese encephalitis, yellow fever, West Nile and chikungunya viruses as well as polymorphism between different Zika virus strains. We used published protein sequences for the Zika virus and obtained protein sequences for the other viruses from the National Center for Biotechnology Information (NCBI) protein database or the NCBI virus variation resource. We used BLASTP to find regions of identity between viruses. We quantified the identity between the Zika virus and each of the other viruses, as well as within-Zika virus polymorphism for all amino acid k -mers across the proteome, with k ranging from 6 to 100. We assessed accessibility of protein fragments by calculating the solvent accessible surface area for the envelope and nonstructural-1 (NS1) proteins. In total, we identified 294 Zika virus protein fragments with both low proportion of identity with other viruses and low levels of polymorphisms among Zika virus strains. The list includes protein fragments from all Zika virus proteins, except NS3. NS4A has the highest number (190 k -mers) of protein fragments on the list. We provide a candidate list of protein fragments that could be used when developing a sensitive and specific serological test to detect previous Zika virus infections.

Blueberry (Vaccinium corymbosum)-Virus Diseases

Science.gov (United States)

At least six viruses have been found in highbush blueberry plantings in the Pacific Northwest: Blueberry mosaic virus, Blueberry red ringspot virus, Blueberry scorch virus, Blueberry shock virus, Tobacco ringspot virus, and Tomato ringspot virus. Six other virus and virus-like diseases of highbush b...

Kajian Potensi Air Rawa dan Kearifan Lokal sebagai Dasar Pengelolaan Air Rawa Yomoth sebagai Sumber Air Bersih di Distrik Agats Kabupaten Asmat Provinsi Papua

Directory of Open Access Journals (Sweden)

Yoseph Kamun

2016-10-01

Tujuanpenelitianiniadalah (1 mengkajikebutuhanairbersihpenduduk dansumber- sumber air bersih di daerah penelitian, (2 mengkaji  karasteristik  potensi  air  rawa Yomoth sebagaisumberairbersihdan(3menyusun  kerangkadasarpengelolaan airrawaYomoth sebagaisumberair bersihyangberbasiskearifanlokal. Metode penelian adalah survey, dengan data diperoleh dan wawancara terhadap koresponden  yangditentukan  secarapurposive  sampling.  Datadianalisis  secara  deskriptip kuantitatif untuk mendapatkan gambaran tentang jumlah angka dan   pembahasan  objek kesimpulansecarakeruangan(spasial.Hasilpenelitianmenunjukkanbahwa:(1KebutuhanairbersihdiKotaAgatsKabupaten Asmatberdasarkansampel30KKyangdiperolehadalahsebesarrata-rata60ltr/harimakatotal kebutuhanair92.46ltr3/haridenganjumlah pendudukKotaAgats1541orang.Makakebutuhan airbersihpada5tahunmendatangadalah14736ltr3dengantingkatpenduduk1615orang,pada 10tahunmendatang  adalah31171ltr3  dengantingkatpenduduk1708orang,pada15tahun mendatangadalah49411ltr3  dengantingkatpenduduk1805orang,pada20tahunmendatang adalah69058ltr3dengantinkatpenduduk1892orangdanpada25tahunmedatangadalah88147 ltr3   dengan  tingkat  penduduk  1932  orang.  (2  Air  rawa  Yomoth  sebagai  sumber  air  bersih mempunyaikapasitasdayadukung2.302.140m3 dengankualitasbaikuntukdikelolasebagai sumbercadanganairbersih,walaupunterdapatpembatasberupasifatfisikairrawa,kandungan unsurkimiadanbiologisnya.(3UpayapengelolaanairrawaYomothdilakukandengancara perlindungan,penyelamatandanpelestarianterhadaphutandansumberdayaairrawa,dengan melakukan  tindakan  perlindungan  kearifan  lokal  dan  peraturan  daerah  sebagai  suatu  dasar hukum dalam pengambilan kebijakan dan keputusan.Mengingat secara ariftelah  melalui

Single virus genomics: a new tool for virus discovery.

Directory of Open Access Journals (Sweden)

Lisa Zeigler Allen

Full Text Available Whole genome amplification and sequencing of single microbial cells has significantly influenced genomics and microbial ecology by facilitating direct recovery of reference genome data. However, viral genomics continues to suffer due to difficulties related to the isolation and characterization of uncultivated viruses. We report here on a new approach called 'Single Virus Genomics', which enabled the isolation and complete genome sequencing of the first single virus particle. A mixed assemblage comprised of two known viruses; E. coli bacteriophages lambda and T4, were sorted using flow cytometric methods and subsequently immobilized in an agarose matrix. Genome amplification was then achieved in situ via multiple displacement amplification (MDA. The complete lambda phage genome was recovered with an average depth of coverage of approximately 437X. The isolation and genome sequencing of uncultivated viruses using Single Virus Genomics approaches will enable researchers to address questions about viral diversity, evolution, adaptation and ecology that were previously unattainable.

Resistance to Two Heterologous Neurotropic Oncolytic Viruses, Semliki Forest Virus and Vaccinia Virus, in Experimental Glioma

Science.gov (United States)

Le Boeuf, Fabrice; Lemay, Chantal; De Silva, Naomi; Diallo, Jean-Simon; Cox, Julie; Becker, Michelle; Choi, Youngmin; Ananth, Abhirami; Sellers, Clara; Breton, Sophie; Roy, Dominic; Falls, Theresa; Brun, Jan; Hemminki, Akseli; Hinkkanen, Ari; Bell, John C.

2013-01-01

Attenuated Semliki Forest virus (SFV) may be suitable for targeting malignant glioma due to its natural neurotropism, but its replication in brain tumor cells may be restricted by innate antiviral defenses. We attempted to facilitate SFV replication in glioma cells by combining it with vaccinia virus, which is capable of antagonizing such defenses. Surprisingly, we found parenchymal mouse brain tumors to be refractory to both viruses. Also, vaccinia virus appears to be sensitive to SFV-induced antiviral interference. PMID:23221568

Detection of sweet potato virus C, sweet potato virus 2 and sweet potato feathery mottle virus in Portugal.

Science.gov (United States)

Varanda, Carla M R; Santos, Susana J; Oliveira, Mônica D M; Clara, Maria Ivone E; Félix, Maria Rosário F

2015-06-01

Field sweet potato plants showing virus-like symptoms, as stunting, leaf distortion, mosaic and chlorosis, were collected in southwest Portugal and tested for the presence of four potyviruses, sweet potato virus C (SPVC), sweet potato virus 2 (SPV2), sweet potato feathery mottle virus (SPFMV), sweet potato virus G (SPVG), and the crinivirus sweet potato chlorotic stunt virus (SPCSV). DsRNA fractions were extracted from symptomatic leaves and used as templates in single and multiplex RT-PCR assays using previously described specific primers for each analyzed virus. The amplified reaction products for SPVC, SPV2 and SPFMV were of expected size, and direct sequencing of PCR products revealed that they correspond to the coat protein gene (CP) and showed 98%, 99% and 99% identity, respectively, to those viruses. Comparison of the CP genomic and amino acid sequences of the Portuguese viral isolates recovered here with those of ten other sequences of isolates obtained in different countries retrieved from the GenBank showed very few differences. The application of the RT-PCR assays revealed for the first time the presence of SPVC and SPFMV in the sweet potato crop in Portugal, the absence of SPVG and SPCSV in tested plants, as well as the occurrence of triple virus infections under field conditions.

Hepatitis E virus and fulminant hepatitis--a virus or host-specific pathology?

Science.gov (United States)

Smith, Donald B; Simmonds, Peter

2015-04-01

Fulminant hepatitis is a rare outcome of infection with hepatitis E virus. Several recent reports suggest that virus variation is an important determinant of disease progression. To critically examine the evidence that virus-specific factors underlie the development of fulminant hepatitis following hepatitis E virus infection. Published sequence information of hepatitis E virus isolates from patients with and without fulminant hepatitis was collected and analysed using statistical tests to identify associations between virus polymorphisms and disease outcome. Fulminant hepatitis has been reported following infection with all four hepatitis E virus genotypes that infect humans comprising multiple phylogenetic lineages within genotypes 1, 3 and 4. Analysis of virus sequences from individuals infected by a common source did not detect any common substitutions associated with progression to fulminant hepatitis. Re-analysis of previously reported associations between virus substitutions and fulminant hepatitis suggests that these were probably the result of sampling biases. Host-specific factors rather than virus genotype, variants or specific substitutions appear to be responsible for the development of fulminant hepatitis. © 2014 The Authors. Liver International Published by John Wiley & Sons Ltd.

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

Science.gov (United States)

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

2014-01-01

Summary 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 higher pathogenicity in mice and ferrets than 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

Lack of Durable Cross-Neutralizing Antibodies Against Zika Virus from Dengue Virus Infection.

Science.gov (United States)

Collins, Matthew H; McGowan, Eileen; Jadi, Ramesh; Young, Ellen; Lopez, Cesar A; Baric, Ralph S; Lazear, Helen M; de Silva, Aravinda M

2017-05-01

Cross-reactive antibodies elicited by dengue virus (DENV) infection might affect Zika virus infection and confound serologic tests. Recent data demonstrate neutralization of Zika virus by monoclonal antibodies or human serum collected early after DENV infection. Whether this finding is true in late DENV convalescence (>6 months after infection) is unknown. We studied late convalescent serum samples from persons with prior DENV or Zika virus exposure. Despite extensive cross-reactivity in IgG binding, Zika virus neutralization was not observed among primary DENV infections. We observed low-frequency (23%) Zika virus cross-neutralization in repeat DENV infections. DENV-immune persons who had Zika virus as a secondary infection had distinct populations of antibodies that neutralized DENVs and Zika virus, as shown by DENV-reactive antibody depletion experiments. These data suggest that most DENV infections do not induce durable, high-level Zika virus cross-neutralizing antibodies. Zika virus-specific antibody populations develop after Zika virus infection irrespective of prior DENV immunity.

Ganjam virus.

Science.gov (United States)

Sudeep, A B; Jadi, R S; Mishra, A C

2009-11-01

Ganjam virus (GANV), a member of genus Nairovirus of family Bunyavirdae is of considerable veterinary importance in India. Though, predominantly tick borne, GANV was also isolated from mosquitoes, man and sheep. Neutralizing and complement fixing antibodies to GANV have been detected in animal and human sera collected from different parts of the country. Thirty three strains of GANV have been isolated from India, mainly from Haemaphysalis ticks. The virus replicated in certain vertebrate and mosquito cell lines and found pathogenic to laboratory animals. One natural infection and five laboratory-acquired infections in men were also reported. GANV is antigenically related to Nairobi sheep disease virus (NSDV) of Africa, which is highly pathogenic for sheep and goats causing 70-90 per cent mortality among the susceptible population. Recent molecular studies have demonstrated that GANV is an Asian variant of NSDV and both these viruses are related to the dreaded Crimean Congo haemorrhagic fever (CCHF) group viruses. The versatility of the virus to replicate in different arthropod species, its ability to infect sheep, goat and man makes it an important zoonotic agent.

The Drosophila Nora virus is an enteric virus, transmitted via feces.

Science.gov (United States)

Habayeb, Mazen S; Cantera, Rafael; Casanova, Gabriela; Ekström, Jens-Ola; Albright, Shannon; Hultmark, Dan

2009-04-01

The biology of the Drosophila viruses has not been intensely investigated. Here we have investigated the biology of the Nora virus, a persistent Drosophila virus. We find that injected Nora virus is able to replicate in the files, reaching a high titer that is maintained in the next generation. There is a remarkable variation in the viral loads of individual flies in persistently infected stocks; the titers can differ by three orders of magnitude. The Nora virus is mainly found in the intestine of infected flies, and the histology of these infected intestines show increased vacuolization. The virus is excreted in the feces and is horizontally transmitted. The Nora virus infection has a very mild effect on the longevity of the flies, and no significant effect on the number of eggs laid and the percent of eggs that develop to adults.

Herpes viruses and human papilloma virus in nasal polyposis and controls

Directory of Open Access Journals (Sweden)

Dimitrios Ioannidis

2015-12-01

Full Text Available ABSTRACT INTRODUCTION: Chronic rhinosinusitis with nasal polyps is a multifactorial disease entity with an unclear pathogenesis. Contradictory data exist in the literature on the potential implication of viral elements in adult patients with chronic rhinosinusitis. OBJECTIVE: To compare the prevalence of human herpes viruses (1-6 and Human Papilloma Virus in adult patients with chronic rhinosinusitis with nasal polyps and healthy controls. METHODS: Viral DNA presence was evaluated by real-time polymerase chain reaction application to nasal polyps specimens from 91 chronic rhinosinusitis with nasal polyps patients and nasal turbinate mucosa from 38 healthy controls. RESULTS: Epstein-Barr virus positivity was higher in nasal polyps (24/91; 26.4% versus controls (4/38; 10.5%, but the difference did not reach significance (p = 0.06. Human herpes virus-6 positivity was lower in nasal polyps (13/91; 14.29% versus controls (10/38; 26.32%,p = 0.13. In chronic rhinosinusitis with nasal polyps group, 1 sample was herpes simplex virus-1-positive (1/91; 1.1%, and another was cytomegalovirus-positive (1/91; 1.1%, versus none in controls. No sample was positive for herpes simplex virus-2, varicella-zoster virus, high-risk-human papilloma viruses (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59 and low-risk-human papilloma viruses (6, 11. CONCLUSION: Differences in Epstein-Barr virus and human herpes virus-6 positivity among patients with chronic rhinosinusitis with nasal polyps and healthy controls are not statistically significant, weakening the likelihood of their implication in chronic rhinosinusitis with nasal polyps pathogenesis.

Evaluation of recombinant influenza virus-simian immunodeficiency virus vaccines in macaques.

Science.gov (United States)

Sexton, Amy; De Rose, Robert; Reece, Jeanette C; Alcantara, Sheilajen; Loh, Liyen; Moffat, Jessica M; Laurie, Karen; Hurt, Aeron; Doherty, Peter C; Turner, Stephen J; Kent, Stephen J; Stambas, John

2009-08-01

There is an urgent need for human immunodeficiency virus (HIV) vaccines that induce robust mucosal immunity. Influenza A viruses (both H1N1 and H3N2) were engineered to express simian immunodeficiency virus (SIV) CD8 T-cell epitopes and evaluated following administration to the respiratory tracts of 11 pigtail macaques. Influenza virus was readily detected from respiratory tract secretions, although the infections were asymptomatic. Animals seroconverted to influenza virus and generated CD8 and CD4 T-cell responses to influenza virus proteins. SIV-specific CD8 T-cell responses bearing the mucosal homing marker beta7 integrin were induced by vaccination of naïve animals. Further, SIV-specific CD8 T-cell responses could be boosted by recombinant influenza virus-SIV vaccination of animals with already-established SIV infection. Sequential vaccination with influenza virus-SIV recombinants of different subtypes (H1N1 followed by H3N2 or vice versa) produced only a limited boost in immunity, probably reflecting T-cell immunity to conserved internal proteins of influenza A virus. SIV challenge of macaques vaccinated with an influenza virus expressing a single SIV CD8 T cell resulted in a large anamnestic recall CD8 T-cell response, but immune escape rapidly ensued and there was no impact on chronic SIV viremia. Although our results suggest that influenza virus-HIV vaccines hold promise for the induction of mucosal immunity to HIV, broader antigen cover will be needed to limit cytotoxic T-lymphocyte escape.

Schmallenberg virus – et nyt virus hos drøvtyggere

DEFF Research Database (Denmark)

Lohse, Louise

undersøgelser på laboratoriet, blev alle prøver i en længere periode testet negative for kendte patogener, der evt. kunne tænkes at knytte sig til disse sygdomsudbrud. Efterfølgende fandt man ved sekvensanalyse på DNA/RNA oprenset fra prøvematerialet lighed med virus fra orthobunyavirusgruppen. Disse virus er...... normalt vektorbårne og er kendt som årsag til sygdom i drøvtyggere i Australien, Asien, Afrika og Mellemøsten. Det nye virus blev kaldt Schmallenberg virus (SBV) efter stedet hvor det første tilfælde blev påvist. Siden har Schmallenberg virus spredt sig og er nu påvist i får, kvæg og geder i Tyskland......, Holland, Belgien, Luxembourg, Frankrig, Spanien, Italien og Storbritannien (status april 2012). Det antages, at virus overføres med mitter og myg og inkubationstiden har fra eksperimentelle forsøg vist sig at være kort (1-4 dage). Virus cirkulerer få dage i blodet og manifesterer sig ved milde uspecifikke...

Sensitive radioimmunosorbent assay for the detection of plant viruses. [Cauliflower mosaic virus, lettuce mosaic virus

Energy Technology Data Exchange (ETDEWEB)

Ghabrial, S A; Shepherd, R J [Kentucky Univ., Lexington (USA); California Univ., Davis (USA))

1980-06-01

A simple and highly sensitive radioimmunosorbent assay (RISA) for the detection of plant viruses is described. The RISA procedure is a microplate method based on the principle of 'double-antibody sandwich' and follows essentially the protocol of the enzyme-linked immunosorbent assay (ELISA) (Clark and Adams, 1977), with the exception that /sup 125/I-labelled ..gamma..-globulin is substituted for the ..gamma..-globulin enzyme conjugate; the bound /sup 125/I-..gamma..-globulin is dissociated by acidification from the double-antibody sandwich. The radioactivity is proportional to virus concentration, and cauliflower mosaic virus (CaMV) and lettuce mosaic virus (LMV) could be detected at concentrations as low as 5 and 2 ng/ml, respectively. Direct evidence of the adverse effects of conjugation with enzyme on the binding abilities of antibodies is presented. The RISA procedure should prove valuable with viruses for which the ELISA values are too low to be dependable.

Release of Virus from Lymphoid Tissue Affects Human Immunodeficiency Virus Type 1 and Hepatitis C Virus Kinetics in the Blood

NARCIS (Netherlands)

Müller, Viktor; Marée, Athanasius F.M.; Boer, R.J. de

2000-01-01

Kinetic parameters of human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV) infections have been estimated from plasma virus levels following perturbation of the chronically infected (quasi-) steady state. We extend previous models by also considering the large pool of virus

Hepatitis E Virus and Related Viruses in Animals.

Science.gov (United States)

Thiry, D; Mauroy, A; Pavio, N; Purdy, M A; Rose, N; Thiry, E; de Oliveira-Filho, E F

2017-02-01

Hepatitis E is an acute human liver disease in healthy individuals which may eventually become chronic. It is caused by the hepatitis E virus (HEV) and can have a zoonotic origin. Nearly 57,000 people die yearly from hepatitis E-related conditions. The disease is endemic in both developing and developed countries with distinct epidemiologic profiles. In developing countries, the disease is associated with inadequate water treatment, while in developed countries, transmission is associated with animal contact and the ingestion of raw or uncooked meat, especially liver. All human HEV are grouped into at least four genotypes, while HEV or HEV-related viruses have been identified in an increasing number of domestic and wild animal species. Despite a high genetic diversity, only one single HEV serotype has been described to date for HEV genotypes 1-4. The discovery of new HEV or HEV-related viruses leads to a continuing increase in the number of genotypes. In addition, the genome organization of all these viruses is variable with overlapping open reading frames (ORF) and differences in the location of ORF3. In spite of the role of some domestic and wild animals as reservoir, the origin of HEV and HEV-related viruses in humans and animals is still unclear. This review discusses aspects of the detection, molecular virology, zoonotic transmission and origin of HEV and HEV-related viruses in the context of 'One Health' and establishes a link between the previous and the new taxonomy of this growing virus family. © 2015 Blackwell Verlag GmbH.

Systematic identification and characterization of regulatory elements derived from human endogenous retroviruses.

Directory of Open Access Journals (Sweden)

Jumpei Ito

2017-07-01

Full Text Available Human endogenous retroviruses (HERVs and other long terminal repeat (LTR-type retrotransposons (HERV/LTRs have regulatory elements that possibly influence the transcription of host genes. We systematically identified and characterized these regulatory elements based on publicly available datasets of ChIP-Seq of 97 transcription factors (TFs provided by ENCODE and Roadmap Epigenomics projects. We determined transcription factor-binding sites (TFBSs using the ChIP-Seq datasets and identified TFBSs observed on HERV/LTR sequences (HERV-TFBSs. Overall, 794,972 HERV-TFBSs were identified. Subsequently, we identified "HERV/LTR-shared regulatory element (HSRE," defined as a TF-binding motif in HERV-TFBSs, shared within a substantial fraction of a HERV/LTR type. HSREs could be an indication that the regulatory elements of HERV/LTRs are present before their insertions. We identified 2,201 HSREs, comprising specific associations of 354 HERV/LTRs and 84 TFs. Clustering analysis showed that HERV/LTRs can be grouped according to the TF binding patterns; HERV/LTR groups bounded to pluripotent TFs (e.g., SOX2, POU5F1, and NANOG, embryonic endoderm/mesendoderm TFs (e.g., GATA4/6, SOX17, and FOXA1/2, hematopoietic TFs (e.g., SPI1 (PU1, GATA1/2, and TAL1, and CTCF were identified. Regulatory elements of HERV/LTRs tended to locate nearby and/or interact three-dimensionally with the genes involved in immune responses, indicating that the regulatory elements play an important role in controlling the immune regulatory network. Further, we demonstrated subgroup-specific TF binding within LTR7, LTR5B, and LTR5_Hs, indicating that gains or losses of the regulatory elements occurred during genomic invasions of the HERV/LTRs. Finally, we constructed dbHERV-REs, an interactive database of HERV/LTR regulatory elements (http://herv-tfbs.com/. This study provides fundamental information in understanding the impact of HERV/LTRs on host transcription, and offers insights into

"The evil virus cell": Students' knowledge and beliefs about viruses.

Science.gov (United States)

Simon, Uwe K; Enzinger, Sonja M; Fink, Andreas

2017-01-01

Education about virus biology at school is of pivotal interest to raise public awareness concerning means of disease transmission and, thus, methods to prevent infection, and to reduce unnecessary antibiotic treatment due to patient pressure on physicians in case of viral diseases such as influenza. This study aimed at making visible the knowledge of Austrian high school and university students with respect to virus biology, virus structure and health-education issues. The data presented here stem from comprehensive questionnaire analyses, including the task to draw a virus, from a cross-sectional study with 133 grade 7 and 199 grade 10 high school students, and 133 first-year biology and 181 first-year non-biology university students. Analyses were performed both quantitatively and qualitatively. ANOVA revealed a highly significant group effect for total knowledge relating to virus biology and health issues (F(3, 642) = 44.17, p students and grade 10 high school students. Students enrolled in university-level biology outperformed all other groups, even though they had not yet encountered this topic at their courses; part of this phenomenon might be due to their affinity for learning about biological topics. However, even many first-year biology students had a high number of severe misconceptions, e.g., defining a virus as a pro- or eukaryotic cell, or falsely naming malaria as a viral disease. Since there was no significant difference in virus-related knowledge between high schools, virus biology seems to have been taught similarly among the tested schools. However, the majority of participants stated that the virus-related knowledge they had acquired at school was not sufficient. Based on the results presented here we urgently suggest improving and intensifying teaching this topic at school, since virus-related knowledge was by far too fragmentary among many participants. Such lack of health-relevant knowledge may contribute to pressure on physicians by patients

Herpes viruses and human papilloma virus in nasal polyposis and controls.

Science.gov (United States)

Ioannidis, Dimitrios; Lachanas, Vasileios A; Florou, Zoe; Bizakis, John G; Petinaki, Efthymia; Skoulakis, Charalampos E

2015-01-01

Chronic rhinosinusitis with nasal polyps is a multifactorial disease entity with an unclear pathogenesis. Contradictory data exist in the literature on the potential implication of viral elements in adult patients with chronic rhinosinusitis. To compare the prevalence of human herpes viruses (1-6) and Human Papilloma Virus in adult patients with chronic rhinosinusitis with nasal polyps and healthy controls. Viral DNA presence was evaluated by real-time polymerase chain reaction application to nasal polyps specimens from 91 chronic rhinosinusitis with nasal polyps patients and nasal turbinate mucosa from 38 healthy controls. Epstein-Barr virus positivity was higher in nasal polyps (24/91; 26.4%) versus controls (4/38; 10.5%), but the difference did not reach significance (p=0.06). Human herpes virus-6 positivity was lower in nasal polyps (13/91; 14.29%) versus controls (10/38; 26.32%, p=0.13). In chronic rhinosinusitis with nasal polyps group, 1 sample was herpes simplex virus-1-positive (1/91; 1.1%), and another was cytomegalovirus-positive (1/91; 1.1%), versus none in controls. No sample was positive for herpes simplex virus-2, varicella-zoster virus, high-risk-human papilloma viruses (16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59) and low-risk-human papilloma viruses (6, 11). Differences in Epstein-Barr virus and human herpes virus-6 positivity among patients with chronic rhinosinusitis with nasal polyps and healthy controls are not statistically significant, weakening the likelihood of their implication in chronic rhinosinusitis with nasal polyps pathogenesis. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

Computer Virus and Trends

OpenAIRE

Tutut Handayani; Soenarto Usna,Drs.MMSI

2004-01-01

Since its appearance the first time in the mid-1980s, computer virus has invited various controversies that still lasts to this day. Along with the development of computer systems technology, viruses komputerpun find new ways to spread itself through a variety of existing communications media. This paper discusses about some things related to computer viruses, namely: the definition and history of computer viruses; the basics of computer viruses; state of computer viruses at this time; and ...

Viruses in reptiles

Directory of Open Access Journals (Sweden)

Ariel Ellen

2011-09-01

Full Text Available Abstract The etiology of reptilian viral diseases can be attributed to a wide range of viruses occurring across different genera and families. Thirty to forty years ago, studies of viruses in reptiles focused mainly on the zoonotic potential of arboviruses in reptiles and much effort went into surveys and challenge trials of a range of reptiles with eastern and western equine encephalitis as well as Japanese encephalitis viruses. In the past decade, outbreaks of infection with West Nile virus in human populations and in farmed alligators in the USA has seen the research emphasis placed on the issue of reptiles, particularly crocodiles and alligators, being susceptible to, and reservoirs for, this serious zoonotic disease. Although there are many recognised reptilian viruses, the evidence for those being primary pathogens is relatively limited. Transmission studies establishing pathogenicity and cofactors are likewise scarce, possibly due to the relatively low commercial importance of reptiles, difficulties with the availability of animals and permits for statistically sound experiments, difficulties with housing of reptiles in an experimental setting or the inability to propagate some viruses in cell culture to sufficient titres for transmission studies. Viruses as causes of direct loss of threatened species, such as the chelonid fibropapilloma associated herpesvirus and ranaviruses in farmed and wild tortoises and turtles, have re-focused attention back to the characterisation of the viruses as well as diagnosis and pathogenesis in the host itself. 1. Introduction 2. Methods for working with reptilian viruses 3. Reptilian viruses described by virus families 3.1. Herpesviridae 3.2. Iridoviridae 3.2.1 Ranavirus 3.2.2 Erythrocytic virus 3.2.3 Iridovirus 3.3. Poxviridae 3.4. Adenoviridae 3.5. Papillomaviridae 3.6. Parvoviridae 3.7. Reoviridae 3.8. Retroviridae and inclusion body disease of Boid snakes 3.9. Arboviruses 3.9.1. Flaviviridae 3

Genomic characterisation of Almpiwar virus, Harrison Dam virus and Walkabout Creek virus; three novel rhabdoviruses from northern Australia

Directory of Open Access Journals (Sweden)

Jane McAllister

2014-09-01

Full Text Available Rhabdoviridae represent a diverse group of viruses with the potential to cause disease in humans, animals and plants. Currently there are nine genera in the family; however a large number of rhabdoviruses remain unassigned. Here we characterise three novel rhabdoviruses genomes. Almpiwar virus (ALMV, isolated from skinks in northern Queensland, is the first completely sequenced rhabdovirus from squamates, with serological studies indicating multiple animal host species. Harrison Dam virus (HARDV and Walkabout Creek virus (WACV were isolated from mosquitoes in the Northern Territory and biting midges in southern Queensland respectively and their vertebrate hosts remain unknown. Serological cross-neutralisation tests with other Australian rhabdoviruses indicate that ALMV, WACV and HARDV are distinct viruses with little antigenic cross-reactivity. Next-generation sequencing revealed that all viruses encode the core proteins common to rhabdoviruses (N, P, M, G and L, plus additional ORFs between the M and G genes. HARDV also contains a small ORF between the G and L genes. Phylogenetic analysis of N and L proteins suggests that HARDV and WACV share a common lineage with the tupaviruses and Sandjimba group, whereas ALMV is a distinct and divergent virus showing no clear relationship to any rhabdovirus except the recently characterised Niahka virus (NIAV.

HIV-1 gp120 induces NFAT nuclear translocation in resting CD4+ T-cells

International Nuclear Information System (INIS)

Cicala, Claudia; Arthos, James; Censoplano, Nina; Cruz, Catherine; Chung, Eva; Martinelli, Elena; Lempicki, Richard A.; Natarajan, Ven; VanRyk, Donald; Daucher, Marybeth; Fauci, Anthony S.

2006-01-01

The replication of human immunodeficiency virus (HIV) in CD4+ T-cells is strongly dependent upon the state of activation of infected cells. Infection of sub-optimally activated cells is believed to play a critical role in both the transmission of virus and the persistence of CD4+ T-cell reservoirs. There is accumulating evidence that HIV can modulate signal-transduction pathways in a manner that may facilitate replication in such cells. We previously demonstrated that HIV gp120 induces virus replication in resting CD4+ T cells isolated from HIV-infected individuals. Here, we show that in resting CD4+ T-cells, gp120 activates NFATs and induces their translocation into the nucleus. The HIV LTR encodes NFAT recognition sites, and NFATs may play a critical role in promoting viral replication in sub-optimally activated cells. These observations provide insight into a potential mechanism by which HIV is able to establish infection in resting cells, which may have implications for both transmission of HIV and the persistence of viral reservoirs

Powassan (POW) Virus Basics

Science.gov (United States)

... Health Professionals Related Topics For International Travelers Powassan Virus Disease Basics Download this fact sheet formatted for ... Virus Disease Fact Sheet (PDF) What is Powassan virus? Powassan virus is a tickborne flavivirus that is ...

Initial characterization of Vaccinia Virus B4 suggests a role in virus spread

Energy Technology Data Exchange (ETDEWEB)

Burles, Kristin; Irwin, Chad R.; Burton, Robyn-Lee [Li Ka Shing Institute of Virology, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada T6G 2S2 (Canada); Schriewer, Jill [Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, St. Louis, MO (United States); Evans, David H. [Li Ka Shing Institute of Virology, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada T6G 2S2 (Canada); Buller, R. Mark [Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, St. Louis, MO (United States); Barry, Michele, E-mail: michele.barry@ualberta.ca [Li Ka Shing Institute of Virology, Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada T6G 2S2 (Canada)

2014-05-15

Currently, little is known about the ankyrin/F-box protein B4. Here, we report that B4R-null viruses exhibited reduced plaque size in tissue culture, and decreased ability to spread, as assessed by multiple-step growth analysis. Electron microscopy indicated that B4R-null viruses still formed mature and extracellular virions; however, there was a slight decrease of virions released into the media following deletion of B4R. Deletion of B4R did not affect the ability of the virus to rearrange actin; however, VACV811, a large vaccinia virus deletion mutant missing 55 open reading frames, had decreased ability to produce actin tails. Using ectromelia virus, a natural mouse pathogen, we demonstrated that virus devoid of EVM154, the B4R homolog, showed decreased spread to organs and was attenuated during infection. This initial characterization suggests that B4 may play a role in virus spread, and that other unidentified mediators of actin tail formation may exist in vaccinia virus. - Highlights: • B4R-null viruses show reduced plaque size, and decreased ability to spread. • B4R-null viruses formed mature and extracellular virions; and rearranged actin. • Virus devoid of EVM154, the B4R homolog, was attenuated during infection. • Initial characterization suggests that B4 may play a role in virus spread. • Unidentified mediators of actin tail formation may exist in vaccinia virus.

Initial characterization of Vaccinia Virus B4 suggests a role in virus spread

International Nuclear Information System (INIS)

Burles, Kristin; Irwin, Chad R.; Burton, Robyn-Lee; Schriewer, Jill; Evans, David H.; Buller, R. Mark; Barry, Michele

2014-01-01

Currently, little is known about the ankyrin/F-box protein B4. Here, we report that B4R-null viruses exhibited reduced plaque size in tissue culture, and decreased ability to spread, as assessed by multiple-step growth analysis. Electron microscopy indicated that B4R-null viruses still formed mature and extracellular virions; however, there was a slight decrease of virions released into the media following deletion of B4R. Deletion of B4R did not affect the ability of the virus to rearrange actin; however, VACV811, a large vaccinia virus deletion mutant missing 55 open reading frames, had decreased ability to produce actin tails. Using ectromelia virus, a natural mouse pathogen, we demonstrated that virus devoid of EVM154, the B4R homolog, showed decreased spread to organs and was attenuated during infection. This initial characterization suggests that B4 may play a role in virus spread, and that other unidentified mediators of actin tail formation may exist in vaccinia virus. - Highlights: • B4R-null viruses show reduced plaque size, and decreased ability to spread. • B4R-null viruses formed mature and extracellular virions; and rearranged actin. • Virus devoid of EVM154, the B4R homolog, was attenuated during infection. • Initial characterization suggests that B4 may play a role in virus spread. • Unidentified mediators of actin tail formation may exist in vaccinia virus

How Hepatitis D Virus Can Hinder the Control of Hepatitis B Virus

NARCIS (Netherlands)

Xiridiou, M.; Borkent-Raven, B.; Hulshof, J.; Wallinga, J.

2009-01-01

Background: Hepatitis D (or hepatitis delta) virus is a defective virus that relies on hepatitis B virus (HBV) for transmission; infection with hepatitis D can occur only as coinfection with HBV or superinfection of an existing HBV infection. Because of the bond between the two viruses, control

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

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Bovine Virus Diarrhea Vaccine, Killed Virus. 113.215 Section 113.215 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS STANDARD...

Influenza (Flu) Viruses

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... Types Seasonal Avian Swine Variant Pandemic Other Influenza (Flu) Viruses Language: English (US) Español Recommend on Facebook ... influenza circulate and cause illness. More Information about Flu Viruses Types of Influenza Viruses Influenza A and ...

[The growth of attenuated strains of canine parvovirus, mink enteritis virus, feline panleukopenia virus, and rabies virus on various types of cell cultures].

Science.gov (United States)

Zuffa, T

1987-10-01

The growth characteristics were studied in the attenuated strains of canine parvovirus CPVA-BN 80/82, mink enteritis virus MEVA-BN 63/82 and feline panleucopenia virus FPVA-BN 110/83 on the stable feline kidney cell line FE, and in the attenuated canine distemper virus CDV-F-BN 10/83 on chicken embryo cell cultures (KEB) and cultures of the stable cell line VERO. When the FE cultures were infected with different parvoviruses in cell suspension at MOI 2-4 TKID50 per cell, the first multiplication of the intracellular virus was recorded 20 hours p. i. In the canine parvovirus, the content of intracellular and extracellular virus continued increasing parallelly until the fourth day; then, from the fourth to the sixth day, the content of extracellular virus still increased whereas that of intracellular virus fell rapidly. In the case of the mink enteritis virus the release of the virus into the culture medium continued parallelly with the production of the cellular virus until the sixth day. In the case of the feline panleucopenia virus the values concerning free virus and virus bound to cells were lower, starting from the second day p. i. When KEB or VERO cultures were infected in cell suspension with the canine distemper virus at MOI about 0.004 per 1 cell, the replicated intracellular virus was first recorded in the KEB cultures five hours after infection but in the VERO cultures only 20 hours after infection, with a timely release of the virus into the culture medium in both kinds of tissue. In the KEB and VERO cultures the highest values of infection titres were recorded on the fourth day p. i., the course of virus multiplication on the cells being parallel with its release into the culture medium.

The population history of endogenous retroviruses in mule deer (Odocoileus heminous)

Science.gov (United States)

Kamath, Pauline L.; Elleder, Daniel; Bao, Le; Cross, Paul C.; Powell, John H.; Poss, Mary

2013-01-01

Mobile elements are powerful agents of genomic evolution and can be exceptionally informative markers for investigating species and population-level evolutionary history. While several studies have utilized retrotransposon-based insertional polymorphisms to resolve phylogenies, few population studies exist outside of humans. Endogenous retroviruses are LTR-retrotransposons derived from retroviruses that have become stably integrated in the host genome during past infections and transmitted vertically to subsequent generations. They offer valuable insight into host-virus co-evolution and a unique perspective on host evolutionary history because they integrate into the genome at a discrete point in time. We examined the evolutionary history of a cervid endogenous gammaretrovirus (CrERVγ) in mule deer (Odocoileus hemionus). We sequenced 14 CrERV proviruses (CrERV-in1 to -in14), and examined the prevalence and distribution of 13 proviruses in 262 deer among 15 populations from Montana, Wyoming, and Utah. CrERV absence in white-tailed deer (O. virginianus), identical 5′ and 3′ long terminal repeat (LTR) sequences, insertional polymorphism, and CrERV divergence time estimates indicated that most endogenization events occurred within the last 200000 years. Population structure inferred from CrERVs (F ST = 0.008) and microsatellites (θ = 0.01) was low, but significant, with Utah, northwestern Montana, and a Helena herd being particularly differentiated. Clustering analyses indicated regional structuring, and non-contiguous clustering could often be explained by known translocations. Cluster ensemble results indicated spatial localization of viruses, specifically in deer from northeastern and western Montana. This study demonstrates the utility of endogenous retroviruses to elucidate and provide novel insight into both ERV evolutionary history and the history of contemporary host populations.

The population history of endogenous retroviruses in mule deer (Odocoileus hemionus).

Science.gov (United States)

Kamath, Pauline L; Elleder, Daniel; Bao, Le; Cross, Paul C; Powell, John H; Poss, Mary

2014-01-01

Mobile elements are powerful agents of genomic evolution and can be exceptionally informative markers for investigating species and population-level evolutionary history. While several studies have utilized retrotransposon-based insertional polymorphisms to resolve phylogenies, few population studies exist outside of humans. Endogenous retroviruses are LTR-retrotransposons derived from retroviruses that have become stably integrated in the host genome during past infections and transmitted vertically to subsequent generations. They offer valuable insight into host-virus co-evolution and a unique perspective on host evolutionary history because they integrate into the genome at a discrete point in time. We examined the evolutionary history of a cervid endogenous gammaretrovirus (CrERVγ) in mule deer (Odocoileus hemionus). We sequenced 14 CrERV proviruses (CrERV-in1 to -in14), and examined the prevalence and distribution of 13 proviruses in 262 deer among 15 populations from Montana, Wyoming, and Utah. CrERV absence in white-tailed deer (O. virginianus), identical 5' and 3' long terminal repeat (LTR) sequences, insertional polymorphism, and CrERV divergence time estimates indicated that most endogenization events occurred within the last 200000 years. Population structure inferred from CrERVs (F ST = 0.008) and microsatellites (θ = 0.01) was low, but significant, with Utah, northwestern Montana, and a Helena herd being particularly differentiated. Clustering analyses indicated regional structuring, and non-contiguous clustering could often be explained by known translocations. Cluster ensemble results indicated spatial localization of viruses, specifically in deer from northeastern and western Montana. This study demonstrates the utility of endogenous retroviruses to elucidate and provide novel insight into both ERV evolutionary history and the history of contemporary host populations.

Novel interactions between the HTLV antisense proteins HBZ and APH-2 and the NFAR protein family: Implications for the HTLV lifecycles

Energy Technology Data Exchange (ETDEWEB)

Murphy, Jane; Hall, William W. [Centre for Research in Infectious Diseases, School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4 (Ireland); Ratner, Lee [Department of Medicine, Division of Molecular Oncology, Washington University School of Medicine, Saint Louis, Missouri, United States of America (United States); Sheehy, Noreen [Centre for Research in Infectious Diseases, School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4 (Ireland)

2016-07-15

The human T-cell leukaemia virus type 1 and type 2 (HTLV-1/HTLV-2) antisense proteins HBZ and APH-2 play key roles in the HTLV lifecycles and persistence in the host. Nuclear Factors Associated with double-stranded RNA (NFAR) proteins NF90/110 function in the lifecycles of several viruses and participate in host innate immunity against infection and oncogenesis. Using GST pulldown and co-immunoprecipitation assays we demonstrate specific novel interactions between HBZ/APH-2 and NF90/110 and characterised the protein domains involved. Moreover we show that NF90/110 significantly enhance Tax mediated LTR activation, an effect that was abolished by HBZ but enhanced by APH-2. Additionally we found that HBZ and APH-2 modulate the promoter activity of survivin and are capable of antagonising NF110-mediated survivin activation. Thus interactions between HTLV antisense proteins and the NFAR protein family have an overall positive impact on HTLV infection. Hence NFARs may represent potential therapeutic targets in HTLV infected cells. - Highlights: • This study demonstrates for the first time interactions between NF90/110 and the HTLV antisense proteins HBZ and APH-2. • We show that NF90/110 significantly enhance LTR activation by the HTLV Tax protein, an effect that is abolished by HBZ but enhanced by APH-2. • The study shows that even though the HTLV antisense proteins activate survivin expression they antagonize the ability of NF90/110 to do so. • Overall we found that NF90/110 positively regulate HTLV infection and as such might represent a therapeutic target in infected cells.

A new sensitive and quantitative HTLV-I-mediated cell fusion assay in T cells

International Nuclear Information System (INIS)

Pare, Marie-Eve; Gauthier, Sonia; Landry, Sebastien; Sun Jiangfeng; Legault, Eric; Leclerc, Denis; Tanaka, Yuetsu; Marriott, Susan J.; Tremblay, Michel J.; Barbeau, Benoit

2005-01-01

Similar to several other viruses, human T cell leukemia virus type I (HTLV-I) induces the formation of multinucleated giant cells (also known as syncytium) when amplified in tissue culture. These syncytia result from the fusion of infected cells with uninfected cells. Due to the intrinsic difficulty of infecting cells with cell-free HTLV-I virions, syncytium formation has become an important tool in the study of HTLV-I infection and transmission. Since most HTLV-I-based cell fusion assays rely on the use of non-T cells, the aim of this study was to optimize a new HTLV-I-induced cell fusion assay in which HTLV-I-infected T cell lines are co-cultured with T cells that have been transfected with an HTLV-I long terminal repeat (LTR) luciferase reporter construct. We demonstrate that co-culture of various HTLV-I-infected T cells with different transfected T cell lines resulted in induction of luciferase activity. Cell-to-cell contact and expression of the viral gp46 envelope protein was crucial for this induction while other cell surface proteins (including HSC70) did not have a significant effect. This quantitative assay was shown to be very sensitive. In this assay, the cell fusion-mediated activation of NF-κB and the HTLV-I LTR occurred through previously described Tax-dependent signaling pathways. This assay also showed that cell fusion could activate Tax-inducible cellular promoters. These results thus demonstrate that this new quantitative HTLV-I-dependent cell fusion assay is versatile, highly sensitive, and can provide an important tool to investigate cellular promoter activation and intrinsic signaling cascades that modulate cellular gene expression

Novel interactions between the HTLV antisense proteins HBZ and APH-2 and the NFAR protein family: Implications for the HTLV lifecycles

International Nuclear Information System (INIS)

Murphy, Jane; Hall, William W.; Ratner, Lee; Sheehy, Noreen

2016-01-01

The human T-cell leukaemia virus type 1 and type 2 (HTLV-1/HTLV-2) antisense proteins HBZ and APH-2 play key roles in the HTLV lifecycles and persistence in the host. Nuclear Factors Associated with double-stranded RNA (NFAR) proteins NF90/110 function in the lifecycles of several viruses and participate in host innate immunity against infection and oncogenesis. Using GST pulldown and co-immunoprecipitation assays we demonstrate specific novel interactions between HBZ/APH-2 and NF90/110 and characterised the protein domains involved. Moreover we show that NF90/110 significantly enhance Tax mediated LTR activation, an effect that was abolished by HBZ but enhanced by APH-2. Additionally we found that HBZ and APH-2 modulate the promoter activity of survivin and are capable of antagonising NF110-mediated survivin activation. Thus interactions between HTLV antisense proteins and the NFAR protein family have an overall positive impact on HTLV infection. Hence NFARs may represent potential therapeutic targets in HTLV infected cells. - Highlights: • This study demonstrates for the first time interactions between NF90/110 and the HTLV antisense proteins HBZ and APH-2. • We show that NF90/110 significantly enhance LTR activation by the HTLV Tax protein, an effect that is abolished by HBZ but enhanced by APH-2. • The study shows that even though the HTLV antisense proteins activate survivin expression they antagonize the ability of NF90/110 to do so. • Overall we found that NF90/110 positively regulate HTLV infection and as such might represent a therapeutic target in infected cells.

Viruses of asparagus.

Science.gov (United States)

Tomassoli, Laura; Tiberini, Antonio; Vetten, Heinrich-Josef

2012-01-01

The current knowledge on viruses infecting asparagus (Asparagus officinalis) is reviewed. Over half a century, nine virus species belonging to the genera Ilarvirus, Cucumovirus, Nepovirus, Tobamovirus, Potexvirus, and Potyvirus have been found in this crop. The potyvirus Asparagus virus 1 (AV1) and the ilarvirus Asparagus virus 2 (AV2) are widespread and negatively affect the economic life of asparagus crops reducing yield and increasing the susceptibility to biotic and abiotic stress. The main properties and epidemiology of AV1 and AV2 as well as diagnostic techniques for their detection and identification are described. Minor viruses and control are briefly outlined. Copyright © 2012 Elsevier Inc. All rights reserved.

Viruses and Breast Cancer

Science.gov (United States)

Lawson, James S.; Heng, Benjamin

2010-01-01

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. PMID:24281093

Viruses and Breast Cancer

International Nuclear Information System (INIS)

Lawson, James S.; Heng, Benjamin

2010-01-01

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

Viruses and Breast Cancer

Energy Technology Data Exchange (ETDEWEB)

Lawson, James S., E-mail: james.lawson@unsw.edu.au; Heng, Benjamin [School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney (Australia)

2010-04-30

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.

NF90 una proteína celular que se une a RNAds inhibe la transactivación del LTR del HIV-1 mediada por TAT

Directory of Open Access Journals (Sweden)

Silvio Urcuqui Inchima

2001-04-01

Full Text Available

La transactivación del LTR de HIV-1 requiere la interacción de la proteína Tat ( trans-activation transcription con la estructura TAR ( trans-activation response, que se encuentra localizada en el extremo 5’ de todos los transcriptos virales. La interacción de la proteína Tat con TAR forma un precomplejo transcripcional indispensable para la eficiente transcripción del genoma viral.
La interacción de diferentes factores celulares (cdk9 y ciclina T, entre otros con el precomplejo Tat-TAR, constituye un complejo estable que facilita la fosforilación de la subunidad mayor de la RNA polimerasa II, asegurando una eficiente elongación de los transcriptos virales. No se han descripto proteínas capaces de regular negativamente la función de Tat con resultados nefastos para la replicación viral. También se ha descrito otro tipo de proteínas celulares con capacidad de interactuar con TAR. El ejemplo mejor caracterizado es la proteína-kinasa dependiente de RNA (PKR, se autofosforila y mediante fosforilación del factor eIF2, inhibe la síntesis de proteínas. Con el presente trabajo se
pretendió aislar y caracterizar otras proteínas celulares capaces de interactuar con la estructura TAR y estudiar su efecto en la función de Tat.

"The evil virus cell": Students‘ knowledge and beliefs about viruses

Science.gov (United States)

Enzinger, Sonja M.; Fink, Andreas

2017-01-01

Education about virus biology at school is of pivotal interest to raise public awareness concerning means of disease transmission and, thus, methods to prevent infection, and to reduce unnecessary antibiotic treatment due to patient pressure on physicians in case of viral diseases such as influenza. This study aimed at making visible the knowledge of Austrian high school and university students with respect to virus biology, virus structure and health-education issues. The data presented here stem from comprehensive questionnaire analyses, including the task to draw a virus, from a cross-sectional study with 133 grade 7 and 199 grade 10 high school students, and 133 first-year biology and 181 first-year non-biology university students. Analyses were performed both quantitatively and qualitatively. ANOVA revealed a highly significant group effect for total knowledge relating to virus biology and health issues (F(3, 642) = 44.17, p students and grade 10 high school students. Students enrolled in university-level biology outperformed all other groups, even though they had not yet encountered this topic at their courses; part of this phenomenon might be due to their affinity for learning about biological topics. However, even many first-year biology students had a high number of severe misconceptions, e.g., defining a virus as a pro- or eukaryotic cell, or falsely naming malaria as a viral disease. Since there was no significant difference in virus-related knowledge between high schools, virus biology seems to have been taught similarly among the tested schools. However, the majority of participants stated that the virus-related knowledge they had acquired at school was not sufficient. Based on the results presented here we urgently suggest improving and intensifying teaching this topic at school, since virus-related knowledge was by far too fragmentary among many participants. Such lack of health-relevant knowledge may contribute to pressure on physicians by patients

Influenza virus inactivated by artificial ribonucleases as a prospective killed virus vaccine.

Science.gov (United States)

Fedorova, Antonina A; Goncharova, Elena P; Kovpak, Mikhail P; Vlassov, Valentin V; Zenkova, Marina A

2012-04-19

The inactivation of viral particles with agents causing minimal damage to the structure of surface epitopes is a well-established approach for the production of killed virus vaccines. Here, we describe new agents for the inactivation of influenza virus, artificial ribonucleases (aRNases), which are chemical compounds capable of cleaving RNA molecules. Several aRNases were identified, exhibiting significant virucidal activity against the influenza A virus and causing a minimal effect on the affinity of monoclonal antibodies for the inactivated virus. Using a murine model of the influenza virus infection, a high protective activity of the aRNase-inactivated virus as a vaccine was demonstrated. The results of the experiments demonstrate the efficacy of novel chemical agents in the preparation of vaccines against influenza and, perhaps, against other infections caused by RNA viruses. Copyright © 2012 Elsevier Ltd. All rights reserved.

[The great virus comeback].

Science.gov (United States)

Forterre, Patrick

2013-01-01

Viruses have been considered for a long time as by-products of biological evolution. This view is changing now as a result of several recent discoveries. Viral ecologists have shown that viral particles are the most abundant biological entities on our planet, whereas metagenomic analyses have revealed an unexpected abundance and diversity of viral genes in the biosphere. Comparative genomics have highlighted the uniqueness of viral sequences, in contradiction with the traditional view of viruses as pickpockets of cellular genes. On the contrary, cellular genomes, especially eukaryotic ones, turned out to be full of genes derived from viruses or related elements (plasmids, transposons, retroelements and so on). The discovery of unusual viruses infecting archaea has shown that the viral world is much more diverse than previously thought, ruining the traditional dichotomy between bacteriophages and viruses. Finally, the discovery of giant viruses has blurred the traditional image of viruses as small entities. Furthermore, essential clues on virus history have been obtained in the last ten years. In particular, structural analyses of capsid proteins have uncovered deeply rooted homologies between viruses infecting different cellular domains, suggesting that viruses originated before the last universal common ancestor (LUCA). These studies have shown that several lineages of viruses originated independently, i.e., viruses are polyphyletic. From the time of LUCA, viruses have coevolved with their hosts, and viral lineages can be viewed as lianas wrapping around the trunk, branches and leaves of the tree of life. Although viruses are very diverse, with genomes encoding from one to more than one thousand proteins, they can all be simply defined as organisms producing virions. Virions themselves can be defined as infectious particles made of at least one protein associated with the viral nucleic acid, endowed with the capability to protect the viral genome and ensure its

Protoplasts and plant viruses

International Nuclear Information System (INIS)

Murakishi, H.; Lesney, M.S.; Carlson, P.

1984-01-01

The use of protoplasts in the study of plant viruses has attracted considerable attention since its inception in the late 1960s. This article is an attempt to assess the current status of protoplasts (primarily) and all cell cultures (in some instances) in studies of virus infection, virus replication, cytopathology, cross-protection, virus resistance, and the use of in vitro methods and genetic engineering to recover virus-resistant plants. These areas of study proved difficult to do entirely with whole plants or plant parts. However, because protoplasts could be synchronously infected with virus, they provided a valuable alternative means of following biochemical and cytological events in relation to the virus growth cycle in a more precise manner than previously possible

Hepatitis A Virus and Hepatitis E Virus: Emerging and Re-Emerging Enterically Transmitted Hepatitis Viruses.

Science.gov (United States)

Lemon, Stanley M; Walker, Christopher M

2018-05-07

Over the past two decades, progress in understanding human infections with hepatitis A virus (HAV) and hepatitis E virus (HEV) has been eclipsed by the priority of combating persistent hepatitis B virus (HBV) and hepatitis C virus (HCV) infections. During that time, the global burden of liver disease caused by enteric hepatitis viruses has not abated. Because of vaccines, hepatitis A has become increasingly a disease of adults instead of early childhood in many regions of the world, resulting in an age-related shift toward more severe disease. HEV has remained endemic in many developing countries, and in well-developed, economically advanced countries it is now recognized as a cause of chronic, progressive liver disease in individuals with compromised immunity. The goal of this collection of articles is to review recent progress and to shine a bright light on gaps in our understanding of how these viruses replicate, cause disease, interact with the liver and host immune system, and are transmitted, along with prospects for improved control in human populations. Renewed efforts to study and compare HAV and HEV biology in humans and animal models have high potential to enhance our understanding of host-pathogen balance in the liver, and may contribute ultimately to the control of other infectious diseases of the liver. Copyright © 2018 Cold Spring Harbor Laboratory Press; all rights reserved.

X-ray crystal structure of the N-terminal region of Moloney murine leukemia virus integrase and its implications for viral DNA recognition: N-Terminal Region of M-MuLV Integrase

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Guan, Rongjin [Center for Advanced Biotechnology and Medicine, Rutgers, The State University of New Jersey, Piscataway New Jersey 08854; Northeast Structural Genomics Consortium, Rutgers, The State University of New Jersey, Piscataway New Jersey 08854; Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway New Jersey 08854; Aiyer, Sriram [Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway New Jersey 08854; Cote, Marie L. [Department of Biochemistry, Robert Wood Johnson Medical School, UMDNJ, Piscataway New Jersey 08854; Xiao, Rong [Center for Advanced Biotechnology and Medicine, Rutgers, The State University of New Jersey, Piscataway New Jersey 08854; Northeast Structural Genomics Consortium, Rutgers, The State University of New Jersey, Piscataway New Jersey 08854; Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway New Jersey 08854; Jiang, Mei [Center for Advanced Biotechnology and Medicine, Rutgers, The State University of New Jersey, Piscataway New Jersey 08854; Northeast Structural Genomics Consortium, Rutgers, The State University of New Jersey, Piscataway New Jersey 08854; Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway New Jersey 08854; Acton, Thomas B. [Center for Advanced Biotechnology and Medicine, Rutgers, The State University of New Jersey, Piscataway New Jersey 08854; Northeast Structural Genomics Consortium, Rutgers, The State University of New Jersey, Piscataway New Jersey 08854; Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway New Jersey 08854; Roth, Monica J. [Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, Piscataway New Jersey 08854; Montelione, Gaetano T. [Center for Advanced Biotechnology and Medicine, Rutgers, The State University of New Jersey, Piscataway New Jersey 08854; Northeast Structural Genomics Consortium, Rutgers, The State University of New Jersey, Piscataway New Jersey 08854; Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway New Jersey 08854; Department of Biochemistry, Robert Wood Johnson Medical School, UMDNJ, Piscataway New Jersey 08854

2017-02-03

The retroviral integrase (IN) carries out the integration of a dsDNA copy of the viral genome into the host DNA, an essential step for viral replication. All IN proteins have three general domains, the N-terminal domain (NTD), the catalytic core domain, and the C-terminal domain. The NTD includes an HHCC zinc finger-like motif, which is conserved in all retroviral IN proteins. Two crystal structures of Moloney murine leukemia virus (M-MuLV) IN N-terminal region (NTR) constructs that both include an N-terminal extension domain (NED, residues 1–44) and an HHCC zinc-finger NTD (residues 45–105), in two crystal forms are reported. The structures of IN NTR constructs encoding residues 1–105 (NTR1–105) and 8–105 (NTR8–105) were determined at 2.7 and 2.15 Å resolution, respectively and belong to different space groups. While both crystal forms have similar protomer structures, NTR1–105 packs as a dimer and NTR8–105 packs as a tetramer in the asymmetric unit. The structure of the NED consists of three anti-parallel β-strands and an α-helix, similar to the NED of prototype foamy virus (PFV) IN. These three β-strands form an extended β-sheet with another β-strand in the HHCC Zn2+ binding domain, which is a unique structural feature for the M-MuLV IN. The HHCC Zn2+ binding domain structure is similar to that in HIV and PFV INs, with variations within the loop regions. Differences between the PFV and MLV IN NEDs localize at regions identified to interact with the PFV LTR and are compared with established biochemical and virological data for M-MuLV. Proteins 2017; 85:647–656.

Evolutionary ecology of virus emergence.

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Dennehy, John J

2017-02-01

The cross-species transmission of viruses into new host populations, termed virus emergence, is a significant issue in public health, agriculture, wildlife management, and related fields. Virus emergence requires overlap between host populations, alterations in virus genetics to permit infection of new hosts, and adaptation to novel hosts such that between-host transmission is sustainable, all of which are the purview of the fields of ecology and evolution. A firm understanding of the ecology of viruses and how they evolve is required for understanding how and why viruses emerge. In this paper, I address the evolutionary mechanisms of virus emergence and how they relate to virus ecology. I argue that, while virus acquisition of the ability to infect new hosts is not difficult, limited evolutionary trajectories to sustained virus between-host transmission and the combined effects of mutational meltdown, bottlenecking, demographic stochasticity, density dependence, and genetic erosion in ecological sinks limit most emergence events to dead-end spillover infections. Despite the relative rarity of pandemic emerging viruses, the potential of viruses to search evolutionary space and find means to spread epidemically and the consequences of pandemic viruses that do emerge necessitate sustained attention to virus research, surveillance, prophylaxis, and treatment. © 2016 New York Academy of Sciences.

A virus of hyperthermophilic archaea with a unique architecture among DNA viruses.

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Rensen, Elena Ilka; Mochizuki, Tomohiro; Quemin, Emmanuelle; Schouten, Stefan; Krupovic, Mart; Prangishvili, David

2016-03-01

Viruses package their genetic material in diverse ways. Most known strategies include encapsulation of nucleic acids into spherical or filamentous virions with icosahedral or helical symmetry, respectively. Filamentous viruses with dsDNA genomes are currently associated exclusively with Archaea. Here, we describe a filamentous hyperthermophilic archaeal virus, Pyrobaculum filamentous virus 1 (PFV1), with a type of virion organization not previously observed in DNA viruses. The PFV1 virion, 400 ± 20 × 32 ± 3 nm, contains an envelope and an inner core consisting of two structural units: a rod-shaped helical nucleocapsid formed of two 14-kDa major virion proteins and a nucleocapsid-encompassing protein sheath composed of a single major virion protein of 18 kDa. The virion organization of PFV1 is superficially similar to that of negative-sense RNA viruses of the family Filoviridae, including Ebola virus and Marburg virus. The linear dsDNA of PFV1 carries 17,714 bp, including 60-bp-long terminal inverted repeats, and contains 39 predicted ORFs, most of which do not show similarities to sequences in public databases. PFV1 is a lytic virus that completely disrupts the host cell membrane at the end of the infection cycle.

DIAGNOSTICS OF VIRUS PHYTOPATHOGENS FRUIT TREE PLUM POX VIRUS, PRUNUS NECROTIC RINGSPOT VIRUS AND PRUNUS DWARF VIRUS BY BIOLOGICAL AND MOLECULAR DIAGNOSTICS

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Július Rozák; Zdenka Gálová

2013-01-01

The aim of this study was to determine the incidence of viral phytopathogen Plum pox virus, Prunus necrotic ringspot virus and Prunus dwarf virus in selected localities of Slovakia and diagnose them using a molecular and biological methods. Forty samples of fruit trees of the genus Prunus, twenty samples from intensive plantings and twenty samples from wild subject were analysed. Biological diagnostic by using biological indicators Prunus persica cv. GF 305, Prunus serrulata cv. Schirofugen a...

Functional properties of Virus-Encoded and Virus-Regulated 7TM Receptors

DEFF Research Database (Denmark)

Spiess, Katja; Rosenkilde, Mette Marie

2014-01-01

During co-evolution with their hosts, viruses have developed several survival strategies that involve exploitation of 7TM receptors. These include virus-encoded 7TM receptors and ligands and viral regulation of endogenous receptors. Many functional properties have been ascribed to virus-exploited...

Electron microscopic identification of Zinga virus as a strain of Rift Valley fever virus.

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Olaleye, O D; Baigent, C L; Mueller, G; Tomori, O; Schmitz, H

1992-01-01

Electron microscopic examination of a negatively stained suspension of Zinga virus showed particles 90-100 nm in diameter, enveloped with spikes 12-20 nm in length and 5 nm in diameter. Further identification of the virus by immune electron microscopy showed the reactivity of human Rift Valley fever virus-positive serum with Zinga virus. Results of this study are in agreement with earlier reports that Zinga virus is a strain of Rift Valley fever virus.

Re-evaluation of lung to thorax transverse area ratio immediately before birth in predicting postnatal short-term outcomes of fetuses with isolated left-sided congenital diaphragmatic hernia: A single center analysis.

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Kido, Saki; Hidaka, Nobuhiro; Sato, Yuka; Fujita, Yasuyuki; Miyoshi, Kina; Nagata, Kouji; Taguchi, Tomoaki; Kato, Kiyoko

2018-05-01

We aimed to investigate whether the lung-to-thorax transverse area ratio (LTR) immediately before birth is of diagnostic value for the prediction of postnatal short-term outcomes in cases of isolated left-sided congenital diaphragmatic hernia (CDH). We retrospectively reviewed the cases of fetal isolated left-sided CDH managed at our institution between April 2008 and July 2016. We divided the patients into two groups based on LTR immediately before birth, using a cut-off value of 0.08. We compared the proportions of subjects within the two groups who survived until discharge using Fisher's exact test. Further, using Spearman's rank correlation, we assessed whether LTR was correlated with length of stay, duration of mechanical ventilation, and supplemental oxygen. Twenty-nine subjects were included (five with LTR < 0.08, and 24 with LTR ≥ 0.08). The proportion of subjects surviving until discharge was 40% (2/5) for patients with LTR < 0.08, as compared with 96% (23/24) for those with LTR ≥ 0.08. LTR measured immediately before birth was negatively correlated with the postnatal length of stay (Spearman's rank correlation coefficient, rs = -0.486), and the duration of supplemental oxygen (rs = -0.537). Further, the duration of mechanical ventilation was longer in patients with a lower LTR value. LTR immediately before birth is useful for the prediction of postnatal short-term outcomes in fetuses with isolated left-sided CDH. In particular, patients with prenatal LTR value less than 0.08 are at increased risk of postnatal death. © 2017 Japanese Teratology Society.

A Novel Human T-lymphotropic Virus Type 1c Molecular Variant in an Indigenous Individual from New Caledonia, Melanesia.

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Olivier Cassar

2017-01-01

Full Text Available Human T-Lymphotropic Virus type 1 (HTLV-1 is endemic among people of Melanesian descent in Papua New Guinea, Solomon Islands and Vanuatu, and in Indigenous populations from Central Australia. Molecular studies revealed that these Australo-Melanesian strains constitute the highly divergent HTLV-1c subtype. New Caledonia is a French overseas territory located in the Southwest Pacific Ocean. HTLV-1 situation is poorly documented in New Caledonia and the molecular epidemiology of HTLV-1 infection remains unknown.Studying 500 older adults Melanesian natives from New Caledonia, we aim to evaluate the HTLV-1 seroprevalence and to molecularly characterize HTLV-1 proviral strains.Plasma from 262 men and 238 females (age range: 60-96 years old, mean age: 70.5 were screened for anti-HTLV-1 antibodies by particle agglutination (PA and indirect immunofluorescence assay (IFA. Serological confirmation was obtained using Western blot assay. DNAs were extracted from peripheral blood buffy coat of HTLV-1 seropositive individuals, and subjected to four series of PCR (LTR-gag; pro-pol; pol-env and tax-LTR. Primers were designed from highly common conserved regions of the major HTLV-1 subtypes to characterize the entire HTLV-1 proviral genome.Among 500 samples, 3 were PA and IFA positive. The overall seroprevalence was 0.6%. The DNA sample from 1 New Caledonian woman (NCP201 was found positive by PCR and the complete HTLV-1 proviral genome (9,033-bp was obtained. The full-length HTLV-1 genomic sequence from a native woman from Vanuatu (EM5, obtained in the frame of our previous studies, was also characterized. Both sequences belonged to the HTLV-1c Australo-Melanesian subtype. The NCP201 strain exhibited 0.3% nucleotide divergence with the EM5 strain from Vanuatu. Furthermore, divergence reached 1.1% to 2.9% with the Solomon and Australian sequences respectively. Phylogenetic analyses on a 522-bp-long fragment of the gp21-env gene showed the existence of two major

Nonhuman Primate Models of Hepatitis A Virus and Hepatitis E Virus Infections.

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Lanford, Robert E; Walker, Christopher M; Lemon, Stanley M

2018-04-23

Although phylogenetically unrelated, human hepatitis viruses share an exclusive or near exclusive tropism for replication in differentiated hepatocytes. This narrow tissue tropism may contribute to the restriction of the host ranges of these viruses to relatively few host species, mostly nonhuman primates. Nonhuman primate models thus figure prominently in our current understanding of the replication and pathogenesis of these viruses, including the enterically transmitted hepatitis A virus (HAV) and hepatitis E virus (HEV), and have also played major roles in vaccine development. This review draws comparisons of HAV and HEV infection from studies conducted in nonhuman primates, and describes how such studies have contributed to our current understanding of the biology of these viruses. Copyright © 2018 Cold Spring Harbor Laboratory Press; all rights reserved.

Zika Virus

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... Funding CDC Activities For Healthcare Providers Clinical Evaluation & Disease Sexual Transmission HIV Infection & Zika Virus Testing for Zika Test Specimens – At Time of Birth Diagnostic Tests Understanding Zika Virus Test Results ...

Hepatitis C virus infection in the human immunodeficiency virus infected patient

DEFF Research Database (Denmark)

Clausen, Louise Nygaard; Lundbo, Lene Fogt; Benfield, Thomas

2014-01-01

Human immunodeficiency virus (HIV) and hepatitis C virus (HCV) share the same transmission routes; therefore, coinfection is frequent. An estimated 5-10 million individuals alone in the western world are infected with both viruses. The majority of people acquire HCV by injection drug use and...

Immunological responses against human papilloma virus and human papilloma virus induced laryngeal cancer.

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Chitose, Shun-ichi; Sakazaki, T; Ono, T; Kurita, T; Mihashi, H; Nakashima, T

2010-06-01

This study aimed to clarify the local immune status in the larynx in the presence of infection or carcinogenesis associated with human papilloma virus. Cytological samples (for human papilloma virus detection) and laryngeal secretions (for immunoglobulin assessment) were obtained from 31 patients with laryngeal disease, during microscopic laryngeal surgery. On histological examination, 12 patients had squamous cell carcinoma, four had laryngeal papilloma and 15 had other benign laryngeal disease. Cytological samples were tested for human papilloma virus DNA using the Hybrid Capture 2 assay. High risk human papilloma virus DNA was detected in 25 per cent of patients (three of 12) with laryngeal cancer. Low risk human papilloma virus DNA was detected only in three laryngeal papilloma patients. The mean laryngeal secretion concentrations of immunoglobulins M, G and A and secretory immunoglobulin A in human papilloma virus DNA positive patients were more than twice those in human papilloma virus DNA negative patients. A statistically significant difference was observed between the secretory immunoglobulin A concentrations in the two groups. Patients with laryngeal cancer had higher laryngeal secretion concentrations of each immunoglobulin type, compared with patients with benign laryngeal disease. The study assessed the mean laryngeal secretion concentrations of each immunoglobulin type in the 12 laryngeal cancer patients, comparing human papilloma virus DNA positive patients (n = 3) and human papilloma virus DNA negative patients (n = 9); the mean concentrations of immunoglobulins M, G and A and secretory immunoglobulin A tended to be greater in human papilloma virus DNA positive cancer patients, compared with human papilloma virus DNA negative cancer patients. These results suggest that the local laryngeal immune response is activated by infection or carcinogenesis due to human papilloma virus. The findings strongly suggest that secretory IgA has inhibitory activity

Deep-Sea Hydrothermal Vent Viruses Compensate for Microbial Metabolism in Virus-Host Interactions.

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He, Tianliang; Li, Hongyun; Zhang, Xiaobo

2017-07-11

Viruses are believed to be responsible for the mortality of host organisms. However, some recent investigations reveal that viruses may be essential for host survival. To date, it remains unclear whether viruses are beneficial or harmful to their hosts. To reveal the roles of viruses in the virus-host interactions, viromes and microbiomes of sediment samples from three deep-sea hydrothermal vents were explored in this study. To exclude the influence of exogenous DNAs on viromes, the virus particles were purified with nuclease (DNase I and RNase A) treatments and cesium chloride density gradient centrifugation. The metagenomic analysis of viromes without exogenous DNA contamination and microbiomes of vent samples indicated that viruses had compensation effects on the metabolisms of their host microorganisms. Viral genes not only participated in most of the microbial metabolic pathways but also formed branched pathways in microbial metabolisms, including pyrimidine metabolism; alanine, aspartate, and glutamate metabolism; nitrogen metabolism and assimilation pathways of the two-component system; selenocompound metabolism; aminoacyl-tRNA biosynthesis; and amino sugar and nucleotide sugar metabolism. As is well known, deep-sea hydrothermal vent ecosystems exist in relatively isolated environments which are barely influenced by other ecosystems. The metabolic compensation of hosts mediated by viruses might represent a very important aspect of virus-host interactions. IMPORTANCE Viruses are the most abundant biological entities in the oceans and have very important roles in regulating microbial community structure and biogeochemical cycles. The relationship between virus and host microbes is broadly thought to be that of predator and prey. Viruses can lyse host cells to control microbial population sizes and affect community structures of hosts by killing specific microbes. However, viruses also influence their hosts through manipulation of bacterial metabolism. We found

Viruses in reptiles.

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Ariel, Ellen

2011-09-21

The etiology of reptilian viral diseases can be attributed to a wide range of viruses occurring across different genera and families. Thirty to forty years ago, studies of viruses in reptiles focused mainly on the zoonotic potential of arboviruses in reptiles and much effort went into surveys and challenge trials of a range of reptiles with eastern and western equine encephalitis as well as Japanese encephalitis viruses. In the past decade, outbreaks of infection with West Nile virus in human populations and in farmed alligators in the USA has seen the research emphasis placed on the issue of reptiles, particularly crocodiles and alligators, being susceptible to, and reservoirs for, this serious zoonotic disease. Although there are many recognised reptilian viruses, the evidence for those being primary pathogens is relatively limited. Transmission studies establishing pathogenicity and cofactors are likewise scarce, possibly due to the relatively low commercial importance of reptiles, difficulties with the availability of animals and permits for statistically sound experiments, difficulties with housing of reptiles in an experimental setting or the inability to propagate some viruses in cell culture to sufficient titres for transmission studies. Viruses as causes of direct loss of threatened species, such as the chelonid fibropapilloma associated herpesvirus and ranaviruses in farmed and wild tortoises and turtles, have re-focused attention back to the characterisation of the viruses as well as diagnosis and pathogenesis in the host itself.

A REVIEW ON ZIKA VIRUS (ZIKV) -A DREADFUL MEMBER OF THE VIRUS FAMILY FLAVIVIRIDAE

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1Rafiya Begum, 2 Raafia Aseena, 3Nuha Rasheed and 4 Abdul Saleem Mohammad

2017-01-01

Research on zika virus examine the virus that is spread to humans through a mosquito bite, with symptoms that include fever, rash, joint pain, and conjuctivities. For most people zika virus is not necessarily anything to worry, as it is not fatal and symptoms are generally mild for period up to a week. Hospitalization because of zika virus is almost always not necessary. However, the zika virus can be extremely dangerous to pregnant womes. Key Words: Zika, virus, transmission, fatal, flavivir...

Type C virus activation in nontransformed mouse cells by uv-irradiated herpes simplex virus

Energy Technology Data Exchange (ETDEWEB)

Hampar, B. (National Institutes of Health, Bethesda, MD); Hatanaka, M.; Aulakh, G.; Derge, J.G.; Lee, L.; Showalter, S.

1977-02-01

Infection of nontransformed mouse cells with uv-irradiated herpes simplex virus (uv-HSV) resulted in the activation of an endogenous xenotropic (x-tropic) type C virus. Synthesis of type C virus persisted for only a few days, with most of the virus remaining cell associated. The levels of type C virus activated by uv-HSV varied depending on the multiplicity of infection (m.o.i.) and the uv dose. At low uv doses, where cell killing occurred, little or no type C virus synthesis was observed. Maximum levels of type C virus synthesis were observed with the minimum uv dose which eliminated cell killing by HSV. Synthesis of type C virus, albeit at lower levels, was still observed at uv doses beyond those required to prevent cell killing.

Type C virus activation in nontransformed mouse cells by uv-irradiated herpes simplex virus

International Nuclear Information System (INIS)

Hampar, B.; Hatanaka, M.; Aulakh, G.; Derge, J.G.; Lee, L.; Showalter, S.

1977-01-01

Infection of nontransformed mouse cells with uv-irradiated herpes simplex virus (uv-HSV) resulted in the activation of an endogenous xenotropic (x-tropic) type C virus. Synthesis of type C virus persisted for only a few days, with most of the virus remaining cell associated. The levels of type C virus activated by uv-HSV varied depending on the multiplicity of infection (m.o.i.) and the uv dose. At low uv doses, where cell killing occurred, little or no type C virus synthesis was observed. Maximum levels of type C virus synthesis were observed with the minimum uv dose which eliminated cell killing by HSV. Synthesis of type C virus, albeit at lower levels, was still observed at uv doses beyond those required to prevent cell killing

Chikungunya virus

Science.gov (United States)

Chikungunya virus infection; Chikungunya ... Where Chikungunya is Found Before 2013, the virus was found in Africa, Asia, Europe, and the Indian and Pacific oceans. In late 2013, outbreaks occurred for the first time in the ...

Perinatal hepatitis B virus detection by hepatitis B virus-DNA analysis.

OpenAIRE

De Virgiliis, S; Frau, F; Sanna, G; Turco, M P; Figus, A L; Cornacchia, G; Cao, A

1985-01-01

Maternal transmission of hepatitis B virus infection in relation to the hepatitis B e antigen/antibody system and serum hepatitis B virus-DNA were evaluated. Results indicate that hepatitis B virus-DNA analysis can identify hepatitis B serum antigen positive mothers who may transmit infection to their offspring.

Virus like particle-based vaccines against emerging infectious disease viruses.

Science.gov (United States)

Liu, Jinliang; Dai, Shiyu; Wang, Manli; Hu, Zhihong; Wang, Hualin; Deng, Fei

2016-08-01

Emerging infectious diseases are major threats to human health. Most severe viral disease outbreaks occur in developing regions where health conditions are poor. With increased international travel and business, the possibility of eventually transmitting infectious viruses between different countries is increasing. The most effective approach in preventing viral diseases is vaccination. However, vaccines are not currently available for numerous viral diseases. Virus-like particles (VLPs) are engineered vaccine candidates that have been studied for decades. VLPs are constructed by viral protein expression in various expression systems that promote the selfassembly of proteins into structures resembling virus particles. VLPs have antigenicity similar to that of the native virus, but are non-infectious as they lack key viral genetic material. VLP vaccines have attracted considerable research interest because they offer several advantages over traditional vaccines. Studies have shown that VLP vaccines can stimulate both humoral and cellular immune responses, which may offer effective antiviral protection. Here we review recent developments with VLP-based vaccines for several highly virulent emerging or re-emerging infectious diseases. The infectious agents discussed include RNA viruses from different virus families, such as the Arenaviridae, Bunyaviridae, Caliciviridae, Coronaviridae, Filoviridae, Flaviviridae, Orthomyxoviridae, Paramyxoviridae, and Togaviridae families.

Immunogenicity of a modified-live virus vaccine against bovine viral diarrhea virus types 1 and 2, infectious bovine rhinotracheitis virus, bovine parainfluenza-3 virus, and bovine respiratory syncytial virus when administered intranasally in young calves.

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Xue, Wenzhi; Ellis, John; Mattick, Debra; Smith, Linda; Brady, Ryan; Trigo, Emilio

2010-05-14

The immunogenicity of an intranasally-administered modified-live virus (MLV) vaccine in 3-8 day old calves was evaluated against bovine viral diarrhea virus (BVDV) types 1 and 2, infectious bovine rhinotracheitis (IBR) virus, parainfluenza-3 (PI-3) virus and bovine respiratory syncytial virus (BRSV). Calves were intranasally vaccinated with a single dose of a multivalent MLV vaccine and were challenged with one of the respective viruses three to four weeks post-vaccination in five separate studies. There was significant sparing of diseases in calves intranasally vaccinated with the MLV vaccine, as indicated by significantly fewer clinical signs, lower rectal temperatures, reduced viral shedding, greater white blood cell and platelet counts, and less severe pulmonary lesions than control animals. This was the first MLV combination vaccine to demonstrate efficacy against BVDV types 1 and 2, IBR, PI-3 and BRSV in calves 3-8 days of age. Copyright 2010 Elsevier Ltd. All rights reserved.

Ocular Tropism of Respiratory Viruses

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Rota, Paul A.; Tumpey, Terrence M.

2013-01-01

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. PMID:23471620

Understanding Ebola Virus Transmission

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Seth Judson

2015-02-01

Full Text Available An unprecedented number of Ebola virus infections among healthcare workers and patients have raised questions about our understanding of Ebola virus transmission. Here, we explore different routes of Ebola virus transmission between people, summarizing the known epidemiological and experimental data. From this data, we expose important gaps in Ebola virus research pertinent to outbreak situations. We further propose experiments and methods of data collection that will enable scientists to fill these voids in our knowledge about the transmission of Ebola virus.

Ganjam virus/Nairobi sheep disease virus induces a pro-inflammatory response in infected sheep

OpenAIRE

bin Tarif, Abid; Lasecka, Lidia; Holzer, Barbara; Baron, Michael D

2012-01-01

Abstract Partly due to climate change, and partly due to changes of human habitat occupation, the impact of tick-borne viruses is increasing. Nairobi sheep disease virus (NSDV) and Ganjam virus (GV) are two names for the same virus, which causes disease in sheep and goats and is currently known to be circulating in India and East Africa. The virus is transmitted by ixodid ticks and causes a severe hemorrhagic disease. We have developed a real-time PCR assay for the virus genome and validated ...

Zika Virus

Science.gov (United States)

... through blood transfusions. There have been outbreaks of Zika virus in the United States, Africa, Southeast Asia, the ... not travel to areas where there is a Zika virus outbreak. If you do decide to travel, first ...

Ganjam virus/Nairobi sheep disease virus induces a pro-inflammatory response in infected sheep

Directory of Open Access Journals (Sweden)

bin Tarif Abid

2012-10-01

Full Text Available Abstract Partly due to climate change, and partly due to changes of human habitat occupation, the impact of tick-borne viruses is increasing. Nairobi sheep disease virus (NSDV and Ganjam virus (GV are two names for the same virus, which causes disease in sheep and goats and is currently known to be circulating in India and East Africa. The virus is transmitted by ixodid ticks and causes a severe hemorrhagic disease. We have developed a real-time PCR assay for the virus genome and validated it in a pilot study of the pathogenicity induced by two different isolates of NSDV/GV. One isolate was highly adapted to tissue culture, grew in most cell lines tested, and was essentially apathogenic in sheep. The second isolate appeared to be poorly adapted to cell culture and retained pathogenicity in sheep. The real-time PCR assay for virus easily detected 4 copies or less of the viral genome, and allowed a quantitative measure of the virus in whole blood. Measurement of the changes in cytokine mRNAs showed similar changes to those observed in humans infected by the closely related virus Crimean Congo hemorrhagic fever virus.

Ganjam virus/Nairobi sheep disease virus induces a pro-inflammatory response in infected sheep.

Science.gov (United States)

Bin Tarif, Abid; Lasecka, Lidia; Holzer, Barbara; Baron, Michael D

2012-10-19

Partly due to climate change, and partly due to changes of human habitat occupation, the impact of tick-borne viruses is increasing. Nairobi sheep disease virus (NSDV) and Ganjam virus (GV) are two names for the same virus, which causes disease in sheep and goats and is currently known to be circulating in India and East Africa. The virus is transmitted by ixodid ticks and causes a severe hemorrhagic disease. We have developed a real-time PCR assay for the virus genome and validated it in a pilot study of the pathogenicity induced by two different isolates of NSDV/GV. One isolate was highly adapted to tissue culture, grew in most cell lines tested, and was essentially apathogenic in sheep. The second isolate appeared to be poorly adapted to cell culture and retained pathogenicity in sheep. The real-time PCR assay for virus easily detected 4 copies or less of the viral genome, and allowed a quantitative measure of the virus in whole blood. Measurement of the changes in cytokine mRNAs showed similar changes to those observed in humans infected by the closely related virus Crimean Congo hemorrhagic fever virus.

Transmission of Influenza A Viruses

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Neumann, Gabriele; Kawaoka, Yoshihiro

2015-01-01

Influenza A viruses cause respiratory infections that range from asymptomatic to deadly in humans. Widespread outbreaks (pandemics) are attributable to ‘novel’ viruses that possess a viral hemagglutinin (HA) gene to which humans lack immunity. After a pandemic, these novel viruses form stable virus lineages in humans and circulate until they are replaced by other novel viruses. The factors and mechanisms that facilitate virus transmission among hosts and the establishment of novel lineages are not completely understood, but the HA and basic polymerase 2 (PB2) proteins are thought to play essential roles in these processes by enabling avian influenza viruses to infect mammals and replicate efficiently in their new host. Here, we summarize our current knowledge of the contributions of HA, PB2, and other viral components to virus transmission and the formation of new virus lineages. PMID:25812763

New frontiers in oncolytic viruses: optimizing and selecting for virus strains with improved efficacy

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Lundstrom K

2018-02-01

Full Text Available Kenneth Lundstrom PanTherapeutics, Lutry, Switzerland Abstract: Oncolytic viruses have demonstrated selective replication and killing of tumor cells. Different types of oncolytic viruses – adenoviruses, alphaviruses, herpes simplex viruses, Newcastle disease viruses, rhabdoviruses, Coxsackie viruses, and vaccinia viruses – have been applied as either naturally occurring or engineered vectors. Numerous studies in animal-tumor models have demonstrated substantial tumor regression and prolonged survival rates. Moreover, clinical trials have confirmed good safety profiles and therapeutic efficacy for oncolytic viruses. Most encouragingly, the first cancer gene-therapy drug – Gendicine, based on oncolytic adenovirus type 5 – was approved in China. Likewise, a second-generation oncolytic herpes simplex virus-based drug for the treatment of melanoma has been registered in the US and Europe as talimogene laherparepvec. Keywords: immunotherapy, viral vectors, clinical trials, drug approval

Postmortem stability of Ebola virus.

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Prescott, Joseph; Bushmaker, Trenton; Fischer, Robert; Miazgowicz, Kerri; Judson, Seth; Munster, Vincent J

2015-05-01

The ongoing Ebola virus outbreak in West Africa has highlighted questions regarding stability of the virus and detection of RNA from corpses. We used Ebola virus-infected macaques to model humans who died of Ebola virus disease. Viable virus was isolated <7 days posteuthanasia; viral RNA was detectable for 10 weeks.

A Foxtail mosaic virus Vector for Virus-Induced Gene Silencing in Maize.

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Mei, Yu; Zhang, Chunquan; Kernodle, Bliss M; Hill, John H; Whitham, Steven A

2016-06-01

Plant viruses have been widely used as vectors for foreign gene expression and virus-induced gene silencing (VIGS). A limited number of viruses have been developed into viral vectors for the purposes of gene expression or VIGS in monocotyledonous plants, and among these, the tripartite viruses Brome mosaic virus and Cucumber mosaic virus have been shown to induce VIGS in maize (Zea mays). We describe here a new DNA-based VIGS system derived from Foxtail mosaic virus (FoMV), a monopartite virus that is able to establish systemic infection and silencing of endogenous maize genes homologous to gene fragments inserted into the FoMV genome. To demonstrate VIGS applications of this FoMV vector system, four genes, phytoene desaturase (functions in carotenoid biosynthesis), lesion mimic22 (encodes a key enzyme of the porphyrin pathway), iojap (functions in plastid development), and brown midrib3 (caffeic acid O-methyltransferase), were silenced and characterized in the sweet corn line Golden × Bantam. Furthermore, we demonstrate that the FoMV infectious clone establishes systemic infection in maize inbred lines, sorghum (Sorghum bicolor), and green foxtail (Setaria viridis), indicating the potential wide applications of this viral vector system for functional genomics studies in maize and other monocots. © 2016 American Society of Plant Biologists. All Rights Reserved.

Efficient production of infectious viruses requires enzymatic activity of Epstein-Barr virus protein kinase.

Science.gov (United States)

Murata, Takayuki; Isomura, Hiroki; Yamashita, Yoriko; Toyama, Shigenori; Sato, Yoshitaka; Nakayama, Sanae; Kudoh, Ayumi; Iwahori, Satoko; Kanda, Teru; Tsurumi, Tatsuya

2009-06-20

The Epstein-Barr virus (EBV) BGLF4 gene product is the only protein kinase encoded by the virus genome. In order to elucidate its physiological roles in viral productive replication, we here established a BGLF4-knockout mutant and a revertant virus. While the levels of viral DNA replication of the deficient mutant were equivalent to those of the wild-type and the revertant, virus production was significantly impaired. Expression of the BGLF4 protein in trans fully complemented the low yield of the mutant virus, while expression of a kinase-dead (K102I) form of the protein failed to restore the virus titer. These results demonstrate that BGLF4 plays a significant role in production of infectious viruses and that the kinase activity is crucial.

Propagation Effect of a Virus Outbreak on a Network with Limited Anti-Virus Ability.

Directory of Open Access Journals (Sweden)

Yonghong Xu

Full Text Available This paper describes a new computer virus spreading model which takes into account the possibility of a virus outbreak on a network with limited anti-virus ability. Then, the model is investigated for the existence of equilibria and their stabilities are proved and illustrated. Moreover, it is found that these two factors are not only relative to the threshold value determining whether the virus becomes extinct or not, but that they are also relative to the virus epidemic levels. Theoretical and experimental results indicate that, in some ways, it would be practically possible to eradicate the virus or suppress its prevalence below a suitable level. Consequently, some suggestions are proposed that may help eradicate or suppress virus propagation over a real computer network.

An introduction to computer viruses

Energy Technology Data Exchange (ETDEWEB)

Brown, D.R.

1992-03-01

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.

Viruses infecting marine molluscs.

Science.gov (United States)

Arzul, Isabelle; Corbeil, Serge; Morga, Benjamin; Renault, Tristan

2017-07-01

Although a wide range of viruses have been reported in marine molluscs, most of these reports rely on ultrastructural examination and few of these viruses have been fully characterized. The lack of marine mollusc cell lines restricts virus isolation capacities and subsequent characterization works. Our current knowledge is mostly restricted to viruses affecting farmed species such as oysters Crassostrea gigas, abalone Haliotis diversicolor supertexta or the scallop Chlamys farreri. Molecular approaches which are needed to identify virus affiliation have been carried out for a small number of viruses, most of them belonging to the Herpesviridae and birnaviridae families. These last years, the use of New Generation Sequencing approach has allowed increasing the number of sequenced viral genomes and has improved our capacity to investigate the diversity of viruses infecting marine molluscs. This new information has in turn allowed designing more efficient diagnostic tools. Moreover, the development of experimental infection protocols has answered some questions regarding the pathogenesis of these viruses and their interactions with their hosts. Control and management of viral diseases in molluscs mostly involve active surveillance, implementation of effective bio security measures and development of breeding programs. However factors triggering pathogen development and the life cycle and status of the viruses outside their mollusc hosts still need further investigations. Copyright © 2017 Elsevier Inc. All rights reserved.

The sunflower (Helianthus annuus L.) genome reflects a recent history of biased accumulation of transposable elements.

Science.gov (United States)

Staton, S Evan; Bakken, Bradley H; Blackman, Benjamin K; Chapman, Mark A; Kane, Nolan C; Tang, Shunxue; Ungerer, Mark C; Knapp, Steven J; Rieseberg, Loren H; Burke, John M

2012-10-01

Aside from polyploidy, transposable elements are the major drivers of genome size increases in plants. Thus, understanding the diversity and evolutionary dynamics of transposable elements in sunflower (Helianthus annuus L.), especially given its large genome size (∼3.5 Gb) and the well-documented cases of amplification of certain transposons within the genus, is of considerable importance for understanding the evolutionary history of this emerging model species. By analyzing approximately 25% of the sunflower genome from random sequence reads and assembled bacterial artificial chromosome (BAC) clones, we show that it is composed of over 81% transposable elements, 77% of which are long terminal repeat (LTR) retrotransposons. Moreover, the LTR retrotransposon fraction in BAC clones harboring genes is disproportionately composed of chromodomain-containing Gypsy LTR retrotransposons ('chromoviruses'), and the majority of the intact chromoviruses contain tandem chromodomain duplications. We show that there is a bias in the efficacy of homologous recombination in removing LTR retrotransposon DNA, thereby providing insight into the mechanisms associated with transposable element (TE) composition in the sunflower genome. We also show that the vast majority of observed LTR retrotransposon insertions have likely occurred since the origin of this species, providing further evidence that biased LTR retrotransposon activity has played a major role in shaping the chromatin and DNA landscape of the sunflower genome. Although our findings on LTR retrotransposon age and structure could be influenced by the selection of the BAC clones analyzed, a global analysis of random sequence reads indicates that the evolutionary patterns described herein apply to the sunflower genome as a whole. © 2012 The Authors. The Plant Journal © 2012 Blackwell Publishing Ltd.

Coinfection with Epstein–Barr Virus (EBV), Human Papilloma Virus (HPV) and Polyoma BK Virus (BKPyV) in Laryngeal, Oropharyngeal and Oral Cavity Cancer

OpenAIRE

Drop, Bartłomiej; Strycharz-Dudziak, Małgorzata; Kliszczewska, Ewa; Polz-Dacewicz, Małgorzata

2017-01-01

Most research providing evidence for the role of oncogenic viruses in head and neck squamous cell carcinoma (SCC) development is focused on one type of virus without analyzing possible interactions between two or more types of viruses. The aim of this study was to analyse the prevalence of co-infection with human papillomavirus (HPV), Epstein–Barr virus (EBV) and polyoma BK virus (BKPyV) in oral, oropharyngeal and laryngeal squamous cell carcinomas in Polish patients. The correlations between...

RNA viruses in the sea.

Science.gov (United States)

Lang, Andrew S; Rise, Matthew L; Culley, Alexander I; Steward, Grieg F

2009-03-01

Viruses are ubiquitous in the sea and appear to outnumber all other forms of marine life by at least an order of magnitude. Through selective infection, viruses influence nutrient cycling, community structure, and evolution in the ocean. Over the past 20 years we have learned a great deal about the diversity and ecology of the viruses that constitute the marine virioplankton, but until recently the emphasis has been on DNA viruses. Along with expanding knowledge about RNA viruses that infect important marine animals, recent isolations of RNA viruses that infect single-celled eukaryotes and molecular analyses of the RNA virioplankton have revealed that marine RNA viruses are novel, widespread, and genetically diverse. Discoveries in marine RNA virology are broadening our understanding of the biology, ecology, and evolution of viruses, and the epidemiology of viral diseases, but there is still much that we need to learn about the ecology and diversity of RNA viruses before we can fully appreciate their contributions to the dynamics of marine ecosystems. As a step toward making sense of how RNA viruses contribute to the extraordinary viral diversity in the sea, we summarize in this review what is currently known about RNA viruses that infect marine organisms.

Reverse genetics of measles virus and resulting multivalent recombinant vaccines: applications of recombinant measles viruses.

Science.gov (United States)

Billeter, M A; Naim, H Y; Udem, S A

2009-01-01

An overview is given on the development of technologies to allow reverse genetics of RNA viruses, i.e., the rescue of viruses from cDNA, with emphasis on nonsegmented negative-strand RNA viruses (Mononegavirales), as exemplified for measles virus (MV). Primarily, these technologies allowed site-directed mutagenesis, enabling important insights into a variety of aspects of the biology of these viruses. Concomitantly, foreign coding sequences were inserted to (a) allow localization of virus replication in vivo through marker gene expression, (b) develop candidate multivalent vaccines against measles and other pathogens, and (c) create candidate oncolytic viruses. The vector use of these viruses was experimentally encouraged by the pronounced genetic stability of the recombinants unexpected for RNA viruses, and by the high load of insertable genetic material, in excess of 6 kb. The known assets, such as the small genome size of the vector in comparison to DNA viruses proposed as vectors, the extensive clinical experience of attenuated MV as vaccine with a proven record of high safety and efficacy, and the low production cost per vaccination dose are thus favorably complemented.

Schmallenberg Virus

Indian Academy of Sciences (India)

IAS Admin

explore the potential of this infection crossing the species barrier and thereby .... The virus targets mainly the brain of the unborn animal resulting in neurological ... The virus is located in the blood of the adult infected animal or in the central ...

A combination in-ovo vaccine for avian influenza virus and Newcastle disease virus.

Science.gov (United States)

Steel, John; Burmakina, Svetlana V; Thomas, Colleen; Spackman, Erica; García-Sastre, Adolfo; Swayne, David E; Palese, Peter

2008-01-24

The protection of poultry from H5N1 highly pathogenic avian influenza A (HPAI) and Newcastle disease virus (NDV) can be achieved through vaccination, as part of a broader disease control strategy. We have previously generated a recombinant influenza virus expressing, (i) an H5 hemagglutinin protein, modified by the removal of the polybasic cleavage peptide and (ii) the ectodomain of the NDV hemagglutinin-neuraminidase (HN) protein in the place of the ectodomain of influenza neuraminidase (Park MS, et al. Proc Natl Acad Sci USA 2006;103(21):8203-8). Here we show this virus is attenuated in primary normal human bronchial epithelial (NHBE) cell culture, and demonstrate protection of C57BL/6 mice from lethal challenge with an H5 HA-containing influenza virus through immunisation with the recombinant virus. In addition, in-ovo vaccination of 18-day-old embryonated chicken eggs provided 90% and 80% protection against highly stringent lethal challenge by NDV and H5N1 virus, respectively. We propose that this virus has potential as a safe in-ovo live, attenuated, bivalent avian influenza and Newcastle disease virus vaccine.

Evaluation of the suitability of a plant virus, pepper mild mottle virus, as a surrogate of human enteric viruses for assessment of the efficacy of coagulation-rapid sand filtration to remove those viruses.

Science.gov (United States)

Shirasaki, N; Matsushita, T; Matsui, Y; Yamashita, R

2018-02-01

Here, we evaluated the removal of three representative human enteric viruses - adenovirus (AdV) type 40, coxsackievirus (CV) B5, and hepatitis A virus (HAV) IB - and one surrogate of human caliciviruses - murine norovirus (MNV) type 1 - by coagulation-rapid sand filtration, using water samples from eight water sources for drinking water treatment plants in Japan. The removal ratios of a plant virus (pepper mild mottle virus; PMMoV) and two bacteriophages (MS2 and φX174) were compared with the removal ratios of human enteric viruses to assess the suitability of PMMoV, MS2, and φX174 as surrogates for human enteric viruses. The removal ratios of AdV, CV, HAV, and MNV, evaluated via the real-time polymerase chain reaction (PCR) method, were 0.8-2.5-log 10 when commercially available polyaluminum chloride (PACl, basicity 1.5) and virgin silica sand were used as the coagulant and filter medium, respectively. The type of coagulant affected the virus removal efficiency, but the age of silica sand used in the rapid sand filtration did not. Coagulation-rapid sand filtration with non-sulfated, high-basicity PACls (basicity 2.1 or 2.5) removed viruses more efficiently than the other aluminum-based coagulants. The removal ratios of MS2 were sometimes higher than those of the three human enteric viruses and MNV, whereas the removal ratios of φX174 tended to be smaller than those of the three human enteric viruses and MNV. In contrast, the removal ratios of PMMoV were similar to and strongly correlated with those of the three human enteric viruses and MNV. Thus, PMMoV appears to be a suitable surrogate for human enteric viruses for the assessment of the efficacy of coagulation-rapid sand filtration to remove viruses. Copyright © 2017 Elsevier Ltd. All rights reserved.

An inactivated whole-virus porcine parvovirus vaccine protects pigs against disease but does not prevent virus shedding even after homologous virus challenge.

Science.gov (United States)

Foerster, Tessa; Streck, André Felipe; Speck, Stephanie; Selbitz, Hans-Joachim; Lindner, Thomas; Truyen, Uwe

2016-06-01

Inactivated whole-virus vaccines against porcine parvovirus (PPV) can prevent disease but not infection and virus shedding after heterologous virus challenge. Here, we showed that the same is true for a homologous challenge. Pregnant sows were vaccinated with an experimental inactivated vaccine based on PPV strain 27a. They were challenged on day 40 of gestation with the virulent porcine parvovirus PPV-27a from which the vaccine was prepared (homologous challenge). On day 90 of gestation, the fetuses from vaccinated sows were protected against disease, while the fetuses of the non-vaccinated sows (control group) exhibited signs of parvovirus disease. All gilts, whether vaccinated or not vaccinated, showed a boost of PPV-specific antibodies indicative of virus infection and replication. Low DNA copy numbers, but not infectious virus, could be demonstrated in nasal or rectal swabs of immunized sows, but high copy numbers of challenge virus DNA as well as infectious virus could both be demonstrated in non-vaccinated sows.

Dinucleotide Composition in Animal RNA Viruses Is Shaped More by Virus Family than by Host Species.

Science.gov (United States)

Di Giallonardo, Francesca; Schlub, Timothy E; Shi, Mang; Holmes, Edward C

2017-04-15

Viruses use the cellular machinery of their hosts for replication. It has therefore been proposed that the nucleotide and dinucleotide compositions of viruses should match those of their host species. If this is upheld, it may then be possible to use dinucleotide composition to predict the true host species of viruses sampled in metagenomic surveys. However, it is also clear that different taxonomic groups of viruses tend to have distinctive patterns of dinucleotide composition that may be independent of host species. To determine the relative strength of the effect of host versus virus family in shaping dinucleotide composition, we performed a comparative analysis of 20 RNA virus families from 15 host groupings, spanning two animal phyla and more than 900 virus species. In particular, we determined the odds ratios for the 16 possible dinucleotides and performed a discriminant analysis to evaluate the capability of virus dinucleotide composition to predict the correct virus family or host taxon from which it was isolated. Notably, while 81% of the data analyzed here were predicted to the correct virus family, only 62% of these data were predicted to their correct subphylum/class host and a mere 32% to their correct mammalian order. Similarly, dinucleotide composition has a weak predictive power for different hosts within individual virus families. We therefore conclude that dinucleotide composition is generally uniform within a virus family but less well reflects that of its host species. This has obvious implications for attempts to accurately predict host species from virus genome sequences alone. IMPORTANCE Determining the processes that shape virus genomes is central to understanding virus evolution and emergence. One question of particular importance is why nucleotide and dinucleotide frequencies differ so markedly between viruses. In particular, it is currently unclear whether host species or virus family has the biggest impact on dinucleotide frequencies and

Monoclonal antibodies against plant viruses

International Nuclear Information System (INIS)

Sandler, E.; Dietzgen, R.G.

1984-01-01

Ever since antigenic properties of plant viruses were discovered antisera have been raised and used for plant virus diagnosis and for the analysis of virus structure as well. From the early qualitative diagnosis method of precipitating the virus in clarified sap of an infected plant and the first quantitative application of the precipitin test vast progress has been made with regard to the development of highly sensitive and highly quantitative methods for virus detection. Of equal importance was the improvement of methods for separating virus from host cell components since the specificity of antisera raised against a virus could be increased by using an antigen for immunization highly concentrated and largely freed from contaminating host substances. The introduction of the enzyme-linked immunosorbent assay (ELISA) into plant virology allows detection of virus in nanogram quantities. Still, the conventionally raised antisera, no matter how pure an antigen was used for immunization, are polyclonal. They contain products of thousands of different antibody-secreting plasma cell clones which can be directed against all antigenic determinants (epitopes) of the virus, but also against antigens of the host plant that may not have been entirely separated from the immunizing virus during the purification procedure. Even after cross adsorption of polyclonal antisera some residual heterogeneity can be expected to remain. Within these boundaries the information gained with polyclonal antisera on virus structure and on virus diagnosis has to be interpreted

Zika Virus and Pregnancy

Science.gov (United States)

... Management Education & Events Advocacy For Patients About ACOG Zika Virus and Pregnancy Home For Patients Zika Virus and ... Patient Education Pamphlets - Spanish Share: PEV002, September 2016 Zika Virus and Pregnancy There are risks to your fetus ...

Zika Virus

Science.gov (United States)

... with facebook share with twitter share with linkedin Zika Virus Credit: NIAID A female Aedes mosquito. This type of mosquito can transmit Zika, ... transmitted to humans through the bite of infected Aedes aegypti mosquitoes. Zika virus can be transmitted from an infected pregnant woman ...

CHANDIPURA VIRUS

Indian Academy of Sciences (India)

First page Back Continue Last page Overview Graphics. CHANDIPURA VIRUS. First isolated from a village called Chandipura near Nagpur in 1965 in India. Belongs to rhabdoviridae family. Used as a Model System to study RNA virus multiplication in the infected cell at molecular level. Notes:

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

International Nuclear Information System (INIS)

Straus, S.E.

1989-01-01

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

Zika Virus and Pregnancy

Medline Plus

Full Text Available ... Management Education & Events Advocacy For Patients About ACOG Zika Virus and Pregnancy Home For Patients Zika Virus ... Patient Education Pamphlets - Spanish Share: PEV002, September 2016 Zika Virus and Pregnancy There are risks to your ...

Zika Virus and Pregnancy

Medline Plus

Full Text Available ... Education & Events Advocacy For Patients About ACOG Zika Virus and Pregnancy Home For Patients Zika Virus and ... Education Pamphlets - Spanish Share: PEV002, September 2016 Zika Virus and Pregnancy There are risks to your fetus ...

What's West Nile Virus?

Science.gov (United States)

... for Educators Search English Español What's West Nile Virus? KidsHealth / For Kids / What's West Nile Virus? Print en español ¿Qué es el Virus del Nilo Occidental? What exactly is the West ...

Zika Virus and Pregnancy

Medline Plus

Full Text Available ... Advocacy For Patients About ACOG Zika Virus and Pregnancy Home For Patients Zika Virus and Pregnancy Page ... Spanish Share: PEV002, September 2016 Zika Virus and Pregnancy There are risks to your fetus if you ...

Human Immunodeficiency Virus and Hepatitis C Virus Co-infection ...

African Journals Online (AJOL)

Human Immunodeficiency Virus and Hepatitis C Virus Co-infection in Cameroon: Investigation of the Genetic Diversity and Virulent ... AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search · USING AJOL · RESOURCES ... DNA sequencing, and bioinformatics tools for sequence management and analysis.

Virus world as an evolutionary network of viruses and capsidless selfish elements.

Science.gov (United States)

Koonin, Eugene V; Dolja, Valerian V

2014-06-01

Viruses were defined as one of the two principal types of organisms in the biosphere, namely, as capsid-encoding organisms in contrast to ribosome-encoding organisms, i.e., all cellular life forms. Structurally similar, apparently homologous capsids are present in a huge variety of icosahedral viruses that infect bacteria, archaea, and eukaryotes. These findings prompted the concept of the capsid as the virus "self" that defines the identity of deep, ancient viral lineages. However, several other widespread viral "hallmark genes" encode key components of the viral replication apparatus (such as polymerases and helicases) and combine with different capsid proteins, given the inherently modular character of viral evolution. Furthermore, diverse, widespread, capsidless selfish genetic elements, such as plasmids and various types of transposons, share hallmark genes with viruses. Viruses appear to have evolved from capsidless selfish elements, and vice versa, on multiple occasions during evolution. At the earliest, precellular stage of life's evolution, capsidless genetic parasites most likely emerged first and subsequently gave rise to different classes of viruses. In this review, we develop the concept of a greater virus world which forms an evolutionary network that is held together by shared conserved genes and includes both bona fide capsid-encoding viruses and different classes of capsidless replicons. Theoretical studies indicate that selfish replicons (genetic parasites) inevitably emerge in any sufficiently complex evolving ensemble of replicators. Therefore, the key signature of the greater virus world is not the presence of a capsid but rather genetic, informational parasitism itself, i.e., various degrees of reliance on the information processing systems of the host. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Replacement of Murine Leukemia Virus Readthrough Mechanism by Human Immunodeficiency Virus Frameshift Allows Synthesis of Viral Proteins and Virus Replication

Science.gov (United States)

Brunelle, Marie-Noëlle; Brakier-Gingras, Léa; Lemay, Guy

2003-01-01

Retroviruses use unusual recoding strategies to synthesize the Gag-Pol polyprotein precursor of viral enzymes. In human immunodeficiency virus, ribosomes translating full-length viral RNA can shift back by 1 nucleotide at a specific site defined by the presence of both a slippery sequence and a downstream stimulatory element made of an extensive secondary structure. This so-called frameshift mechanism could become a target for the development of novel antiviral strategies. A different recoding strategy is used by other retroviruses, such as murine leukemia viruses, to synthesize the Gag-Pol precursor; in this case, a stop codon is suppressed in a readthrough process, again due to the presence of a specific structure adopted by the mRNA. Development of antiframeshift agents will greatly benefit from the availability of a simple animal and virus model. For this purpose, the murine leukemia virus readthrough region was rendered inactive by mutagenesis and the frameshift region of human immunodeficiency virus was inserted to generate a chimeric provirus. This substitution of readthrough by frameshift allows the synthesis of viral proteins, and the chimeric provirus sequence was found to generate infectious viruses. This system could be a most interesting alternative to study ribosomal frameshift in the context of a virus amenable to the use of a simple animal model. PMID:12584361

[Mumps vaccine virus transmission].

Science.gov (United States)

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

2013-01-01

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.

Zika Virus and Pregnancy

Medline Plus

Full Text Available ... Management Education & Events Advocacy For Patients About ACOG Zika Virus and Pregnancy Home For Patients Zika Virus and ... Patient Education Pamphlets - Spanish Share: PEV002, September 2016 Zika Virus and Pregnancy There are risks to your fetus ...

Zika Virus Fact Sheet

Science.gov (United States)

... is caused by a virus transmitted primarily by Aedes mosquitoes. People with Zika virus disease can have symptoms including mild fever, skin ... framework. Q&A: Zika virus and complication ... mosquito from the Aedes genus, mainly Aedes aegypti in tropical regions. Aedes ...

Computer Viruses: An Overview.

Science.gov (United States)

Marmion, Dan

1990-01-01

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)

An infectious bat-derived chimeric influenza virus harbouring the entry machinery of an influenza A virus.

Science.gov (United States)

Juozapaitis, Mindaugas; Aguiar Moreira, Étori; Mena, Ignacio; Giese, Sebastian; Riegger, David; Pohlmann, Anne; Höper, Dirk; Zimmer, Gert; Beer, Martin; García-Sastre, Adolfo; Schwemmle, Martin

2014-07-23

In 2012, the complete genomic sequence of a new and potentially harmful influenza A-like virus from bats (H17N10) was identified. However, infectious influenza virus was neither isolated from infected bats nor reconstituted, impeding further characterization of this virus. Here we show the generation of an infectious chimeric virus containing six out of the eight bat virus genes, with the remaining two genes encoding the haemagglutinin and neuraminidase proteins of a prototypic influenza A virus. This engineered virus replicates well in a broad range of mammalian cell cultures, human primary airway epithelial cells and mice, but poorly in avian cells and chicken embryos without further adaptation. Importantly, the bat chimeric virus is unable to reassort with other influenza A viruses. Although our data do not exclude the possibility of zoonotic transmission of bat influenza viruses into the human population, they indicate that multiple barriers exist that makes this an unlikely event.

Zika virus infection.

Science.gov (United States)

Pougnet, Laurence; Thill, Chloé; Pougnet, Richard; Auvinet, Henri; Giacardi, Christophe; Drouillard, Isabelle

2016-12-01

A 21-year old woman from New-Caledonia had 40 ̊C fever with vomiting, arthralgia, myalgia, and measles-like rash. Etiological analyses showed primary infection with Zika virus. Because of severe clinical presentation, she was hospitalized in the intensive care unit of the Brest military Hospital. Zika virus is mainly transmitted by Aedes mosquitoes. If they settle in Metropolitan France, Zika virus might also spread there.

Comparative analysis of rabbit hemorrhagic disease virus (RHDV) and new RHDV2 virus antigenicity, using specific virus-like particles.

Science.gov (United States)

Bárcena, Juan; Guerra, Beatriz; Angulo, Iván; González, Julia; Valcárcel, Félix; Mata, Carlos P; Castón, José R; Blanco, Esther; Alejo, Alí

2015-09-24

In 2010 a new Lagovirus related to rabbit haemorrhagic disease virus (RHDV) emerged in France and has since rapidly spread throughout domestic and wild rabbit populations of several European countries. The new virus, termed RHDV2, exhibits distinctive genetic, antigenic and pathogenic features. Notably, RHDV2 kills rabbits previously vaccinated with RHDV vaccines. Here we report for the first time the generation and characterization of RHDV2-specific virus-like particles (VLPs). Our results further confirmed the differential antigenic properties exhibited by RHDV and RHDV2, highlighting the need of using RHDV2-specific diagnostic assays to monitor the spread of this new virus.

Structural and Functional Studies on the Fusion and Attachment Envelope Glycoproteins of Nipah Virus and Hendra Virus

Science.gov (United States)

2003-01-01

including measles virus (MeV), mumps virus, Sendai virus (SeV), Newcastle disease virus (NDV), rinderpest virus, canine distemper virus (CDV), human...Institute of Health, Bethesda, MD. Hut 102, MT2, MT4, and CEM human T cell lines were provided by Chou-Zen Giam, USUHS, Bethesda, MD. The human osteosarcoma

[Using IRAP markers for analysis of genetic variability in populations of resource and rare species of plants].

Science.gov (United States)

Boronnikova, S V; Kalendar', R N

2010-01-01

Species-specific LTR retrotransposons were first cloned in five rare relic species of drug plants located in the Perm' region. Sequences of LTR retrotransposons were used for PCR analysis based on amplification of repeated sequences from LTR or other sites of retrotransposons (IRAP). Genetic diversity was studied in six populations of rare relic species of plants Adonis vernalis L. by means of the IRAP method; 125 polymorphic IRAP-markers were analyzed. Parameters for DNA polymorphism and genetic diversity of A. vernalis populations were determined.

Single Assay Detection of Acute Bee Paralysis Virus, Kashmir Bee Virus and Israeli Acute Paralysis Virus

DEFF Research Database (Denmark)

Francis, Roy Mathew; Kryger, Per

2012-01-01

A new RT-PCR primer pair designed to identify Acute Bee Paralysis Virus (ABPV), Kashmir Bee Virus (KBV) or Israeli Acute Bee Paralysis Virus (IAPV) of honey bees (Apis mellifera L.) in a single assay is described. These primers are used to screen samples for ABPV, KBV, or IAPV in a single RT-PCR ......-PCR reaction saving time and money. The primers are located in the predicted overlapping gene (pog/ORFX) which is highly conserved across ABPV, KBV, IAPV and other dicistroviruses of social insects. This study has also identified the first case of IAPV in Denmark....

Structure of viruses: a short history.

Science.gov (United States)

Rossmann, Michael G

2013-05-01

This review is a partially personal account of the discovery of virus structure and its implication for virus function. Although I have endeavored to cover all aspects of structural virology and to acknowledge relevant individuals, I know that I have favored taking examples from my own experience in telling this story. I am anxious to apologize to all those who I might have unintentionally offended by omitting their work. The first knowledge of virus structure was a result of Stanley's studies of tobacco mosaic virus (TMV) and the subsequent X-ray fiber diffraction analysis by Bernal and Fankuchen in the 1930s. At about the same time it became apparent that crystals of small RNA plant and animal viruses could diffract X-rays, demonstrating that viruses must have distinct and unique structures. More advances were made in the 1950s with the realization by Watson and Crick that viruses might have icosahedral symmetry. With the improvement of experimental and computational techniques in the 1970s, it became possible to determine the three-dimensional, near-atomic resolution structures of some small icosahedral plant and animal RNA viruses. It was a great surprise that the protecting capsids of the first virus structures to be determined had the same architecture. The capsid proteins of these viruses all had a 'jelly-roll' fold and, furthermore, the organization of the capsid protein in the virus were similar, suggesting a common ancestral virus from which many of today's viruses have evolved. By this time a more detailed structure of TMV had also been established, but both the architecture and capsid protein fold were quite different to that of the icosahedral viruses. The small icosahedral RNA virus structures were also informative of how and where cellular receptors, anti-viral compounds, and neutralizing antibodies bound to these viruses. However, larger lipid membrane enveloped viruses did not form sufficiently ordered crystals to obtain good X-ray diffraction

Computer Viruses: Pathology and Detection.

Science.gov (United States)

Maxwell, John R.; Lamon, William E.

1992-01-01

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)

Yeast for virus research

Science.gov (United States)

Zhao, Richard Yuqi

2017-01-01

Budding yeast (Saccharomyces cerevisiae) and fission yeast (Schizosaccharomyces pombe) are two popular model organisms for virus research. They are natural hosts for viruses as they carry their own indigenous viruses. Both yeasts have been used for studies of plant, animal and human viruses. Many positive sense (+) RNA viruses and some DNA viruses replicate with various levels in yeasts, thus allowing study of those viral activities during viral life cycle. Yeasts are single cell eukaryotic organisms. Hence, many of the fundamental cellular functions such as cell cycle regulation or programed cell death are highly conserved from yeasts to higher eukaryotes. Therefore, they are particularly suited to study the impact of those viral activities on related cellular activities during virus-host interactions. Yeasts present many unique advantages in virus research over high eukaryotes. Yeast cells are easy to maintain in the laboratory with relative short doubling time. They are non-biohazardous, genetically amendable with small genomes that permit genome-wide analysis of virologic and cellular functions. In this review, similarities and differences of these two yeasts are described. Studies of virologic activities such as viral translation, viral replication and genome-wide study of virus-cell interactions in yeasts are highlighted. Impacts of viral proteins on basic cellular functions such as cell cycle regulation and programed cell death are discussed. Potential applications of using yeasts as hosts to carry out functional analysis of small viral genome and to develop high throughput drug screening platform for the discovery of antiviral drugs are presented. PMID:29082230

Special Issue: Honey Bee Viruses

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Sebastian Gisder

2015-10-01

Full Text Available Pollination of flowering plants is an important ecosystem service provided by wild insect pollinators and managed honey bees. Hence, losses and declines of pollinating insect species threaten human food security and are of major concern not only for apiculture or agriculture but for human society in general. Honey bee colony losses and bumblebee declines have attracted intensive research interest over the last decade and although the problem is far from being solved we now know that viruses are among the key players of many of these bee losses and bumblebee declines. With this special issue on bee viruses we, therefore, aimed to collect high quality original papers reflecting the current state of bee virus research. To this end, we focused on newly discovered viruses (Lake Sinai viruses, bee macula-like virus, or a so far neglected virus species (Apis mellifera filamentous virus, and cutting edge technologies (mass spectrometry, RNAi approach applied in the field.

Special Issue: Honey Bee Viruses

Science.gov (United States)

Gisder, Sebastian; Genersch, Elke

2015-01-01

Pollination of flowering plants is an important ecosystem service provided by wild insect pollinators and managed honey bees. Hence, losses and declines of pollinating insect species threaten human food security and are of major concern not only for apiculture or agriculture but for human society in general. Honey bee colony losses and bumblebee declines have attracted intensive research interest over the last decade and although the problem is far from being solved we now know that viruses are among the key players of many of these bee losses and bumblebee declines. With this special issue on bee viruses we, therefore, aimed to collect high quality original papers reflecting the current state of bee virus research. To this end, we focused on newly discovered viruses (Lake Sinai viruses, bee macula-like virus), or a so far neglected virus species (Apis mellifera filamentous virus), and cutting edge technologies (mass spectrometry, RNAi approach) applied in the field. PMID:26702462

Diversity of viruses in Ixodes ricinus, and characterization of a neurotropic strain of Eyach virus.

Science.gov (United States)

Moutailler, S; Popovici, I; Devillers, E; Vayssier-Taussat, M; Eloit, M

2016-05-01

Ticks transmit more pathogens-including bacteria, parasites and viruses-than any other arthropod vector. Although the epidemiological status of many tick-borne bacteria is very well characterized, tick-borne viruses are still relatively under-studied. Recently, several novel tick-borne viruses have been isolated from human febrile illnesses following tick bites, indicating the existence of other potential new and unknown tick-borne viruses. We used high-throughput sequencing to analyse the virome of Ixodes ricinus, the main vector of tick-borne pathogens in Europe. The majority of collected viral sequences were assigned to two potentially novel Nairovirus and Phlebovirus viruses, with prevalence rates ranging from 3.95% to 23.88% in adults and estimated to be between 0.14% and 72.16% in nymphs. These viruses could not be isolated from the brains of inoculated immunocompromised mice, perhaps indicating that they are unable to infect vertebrates. Within the I. ricinus virome, we also identified contigs with >90% identity to the known Eyach virus. Initially isolated in the 1980s, this virus was indirectly associated with human disease, but had never been extensively studied. Eyach virus prevalence varied between 0.07% and 5.26% in ticks from the French Ardennes and Alsace regions. Eyach virus was successfully isolated following intracerebral inoculation of immunocompromised mice with Eyach virus-positive tick extracts. This virus was also able to multiply and persist in the blood of immunocompetent mice inoculated by intraperitoneal injection, and caused brain infections in three of nine juveniles, without any obvious deleterious effects.

Zika Virus: An Emerging Worldwide Threat

OpenAIRE

Irfan A. Rather; Jameel B. Lone; Vivek K. Bajpai; Woon K. Paek; Jeongheui Lim

2017-01-01

ZIKA virus (ZIKV) poses a severe threat to the world. Recent outbreaks of ZIKV after 2007 along with its quick transmission have made this virus a matter of international concern. The virus shows symptoms that are similar to those caused in the wake of dengue virus (DENV) and other flaviviruses, which makes it difficult to discern the viral infection. Diagnosis is further complicated as the virus cross-reacts with antibodies of other viruses. Currently, molecular diagnosis of the virus is bei...

How hepatitis D virus can hinder the control of hepatitis B virus.

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Maria Xiridou

Full Text Available BACKGROUND: Hepatitis D (or hepatitis delta virus is a defective virus that relies on hepatitis B virus (HBV for transmission; infection with hepatitis D can occur only as coinfection with HBV or superinfection of an existing HBV infection. Because of the bond between the two viruses, control measures for HBV may have also affected the spread of hepatitis D, as evidenced by the decline of hepatitis D in recent years. Since the presence of hepatitis D is associated with suppressed HBV replication and possibly infectivity, it is reasonable to speculate that hepatitis D may facilitate the control of HBV. METHODOLOGY AND PRINCIPAL FINDINGS: We introduced a mathematical model for the transmission of HBV and hepatitis D, where individuals with dual HBV and hepatitis D infection transmit both viruses. We calculated the reproduction numbers of single HBV infections and dual HBV and hepatitis D infections and examined the endemic prevalences of the two viruses. The results show that hepatitis D virus modulates not only the severity of the HBV epidemic, but also the impact of interventions for HBV. Surprisingly we find that the presence of hepatitis D virus may hamper the eradication of HBV. Interventions that aim to reduce the basic reproduction number of HBV below one may not be sufficient to eradicate the virus, as control of HBV depends also on the reproduction numbers of dual infections. CONCLUSIONS AND SIGNIFICANCE: For populations where hepatitis D is endemic, plans for control programs ignoring the presence of hepatitis D may underestimate the HBV epidemic and produce overoptimistic results. The current HBV surveillance should be augmented with monitoring of hepatitis D, in order to improve accuracy of the monitoring and the efficacy of control measures.

Archaeal viruses of the sulfolobales

DEFF Research Database (Denmark)

Erdmann, Susanne; Garrett, Roger Antony

2015-01-01

in CRISPR loci of Sulfolobus species from a second coinfecting conjugative plasmid or virus (Erdmann and Garrett, Mol Microbiol 85:1044-1056, 2012; Erdmann et al. Mol Microbiol 91:900-917, 2014). Here we describe, firstly, the isolation of archaeal virus mixtures from terrestrial hot springs...... with an environmental virus mixture isolated from Yellowstone National Park (Erdmann and Garrett, Mol Microbiol 85:1044-1056, 2012). Experimental studies of isolated genetic elements from this mixture revealed that SMV1 (S ulfolobus Monocauda Virus 1), a tailed spindle-shaped virus, can induce spacer acquisition...... and the techniques used both to infect laboratory strains with these virus mixtures and to obtain purified virus particles. Secondly, we present the experimental conditions required for activating SMV1-induced spacer acquisition in two different Sulfolobus species....

Seasonal and pandemic human influenza viruses attach better to human upper respiratory tract epithelium than avian influenza viruses.

Science.gov (United States)

van Riel, Debby; den Bakker, Michael A; Leijten, Lonneke M E; Chutinimitkul, Salin; Munster, Vincent J; de Wit, Emmie; Rimmelzwaan, Guus F; Fouchier, Ron A M; Osterhaus, Albert D M E; Kuiken, Thijs

2010-04-01

Influenza viruses vary markedly in their efficiency of human-to-human transmission. This variation has been speculated to be determined in part by the tropism of influenza virus for the human upper respiratory tract. To study this tropism, we determined the pattern of virus attachment by virus histochemistry of three human and three avian influenza viruses in human nasal septum, conchae, nasopharynx, paranasal sinuses, and larynx. We found that the human influenza viruses-two seasonal influenza viruses and pandemic H1N1 virus-attached abundantly to ciliated epithelial cells and goblet cells throughout the upper respiratory tract. In contrast, the avian influenza viruses, including the highly pathogenic H5N1 virus, attached only rarely to epithelial cells or goblet cells. Both human and avian viruses attached occasionally to cells of the submucosal glands. The pattern of virus attachment was similar among the different sites of the human upper respiratory tract for each virus tested. We conclude that influenza viruses that are transmitted efficiently among humans attach abundantly to human upper respiratory tract, whereas inefficiently transmitted influenza viruses attach rarely. These results suggest that the ability of an influenza virus to attach to human upper respiratory tract is a critical factor for efficient transmission in the human population.

Mutagenesis-mediated virus extinction: virus-dependent effect of viral load on sensitivity to lethal defection.

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Héctor Moreno

Full Text Available BACKGROUND: Lethal mutagenesis is a transition towards virus extinction mediated by enhanced mutation rates during viral genome replication, and it is currently under investigation as a potential new antiviral strategy. Viral load and virus fitness are known to influence virus extinction. Here we examine the effect or the multiplicity of infection (MOI on progeny production of several RNA viruses under enhanced mutagenesis. RESULTS: The effect of the mutagenic base analogue 5-fluorouracil (FU on the replication of the arenavirus lymphocytic choriomeningitis virus (LCMV can result either in inhibition of progeny production and virus extinction in infections carried out at low multiplicity of infection (MOI, or in a moderate titer decrease without extinction at high MOI. The effect of the MOI is similar for LCMV and vesicular stomatitis virus (VSV, but minimal or absent for the picornaviruses foot-and-mouth disease virus (FMDV and encephalomyocarditis virus (EMCV. The increase in mutation frequency and Shannon entropy (mutant spectrum complexity as a result of virus passage in the presence of FU was more accentuated at low MOI for LCMV and VSV, and at high MOI for FMDV and EMCV. We present an extension of the lethal defection model that agrees with the experimental results. CONCLUSIONS: (i Low infecting load favoured the extinction of negative strand viruses, LCMV or VSV, with an increase of mutant spectrum complexity. (ii This behaviour is not observed in RNA positive strand viruses, FMDV or EMCV. (iii The accumulation of defector genomes may underlie the MOI-dependent behaviour. (iv LCMV coinfections are allowed but superinfection is strongly restricted in BHK-21 cells. (v The dissimilar effects of the MOI on the efficiency of mutagenic-based extinction of different RNA viruses can have implications for the design of antiviral protocols based on lethal mutagenesis, presently under development.

Coinfection of hepatitis E virus and other hepatitis virus in Colombia and its genotypic characterization.

Science.gov (United States)

Peláez, Dioselina; Martínez-Vargas, Daniel; Escalante-Mora, Martha; Palacios-Vivero, Mariel; Contreras-Gómez, Lady

2015-12-04

Hepatitis E virus has emerged as a public health problem, particularly in developing countries. The four genotypes identified in mammals include the G3 found in indigenous hepatitis in countries and regions with high porcine population, and the G1, associated with maternal deaths.  To determine coinfection by hepatitis E virus and the circulating genotypes in Colombia in 1,097 samples using serological markers for hepatitis A, B and C.  Serum samples of 1,097 patients from different regions of Colombia stored at the Laboratorio de Virología of the Instituto Nacional de Salud were selected to detect IgG and IgM anti-hepatitis E virus antibodies. The viral genomes of positive samples were amplified by RT-PCR, and the products were sequenced and phylogenetically analyzed by comparing ORF2 sequences deposited in the GenBank.  IgG anti-hepatitis E virus antibodies were found in 278 samples, IgM in 62, and both markers in 64. Hepatitis E virus and hepatitis A virus coinfection determined by IgG anti-hepatitis E virus was 33.6% and 16.1% by IgM; hepatitis E virus and hepatitis B virus coinfection was 23.4% and 8.1%, and hepatitis E virus and hepatitis C virus coinfection was 35.4% and 5.83%, respectively. Among the 52 positive samples by PCR nine were sequenced and grouped within genotype 3A of the American porcine strain.  The highest seropositivity was observed for hepatitis A and E. The incidence of hepatitis E virus coinfection with other hepatotropic viruses indicated that this pathogen is more frequent than expected. The circulation of genotype 3A implies that this disease may occur in outbreaks and as zoonosis in Colombia.

Comparative Pathology of Hepatitis A Virus and Hepatitis E Virus Infection.

Science.gov (United States)

Cullen, John M; Lemon, Stanley M

2018-04-30

Hepatitis A virus (HAV) and hepatitis E virus (HEV) cause acute, self-limiting hepatic infections that are usually spread by the fecal-oral route in humans. Naturally occurring and experimental infections are possible in a variety of nonhuman primates and, in the case of HEV, a number of other species. Many advances in understanding the pathogenesis of these viruses have come from studies in experimental animals. In general, animals infected with these viruses recapitulate the histologic lesions seen in infected humans, but typically with less severe clinical and histopathological manifestations. This review describes the histopathologic changes associated with HAV and HEV infection in humans and experimental animals. Copyright © 2018 Cold Spring Harbor Laboratory Press; all rights reserved.

[Zika virus infection during pregnancy].

Science.gov (United States)

Picone, O; Vauloup-Fellous, C; D'Ortenzio, E; Huissoud, C; Carles, G; Benachi, A; Faye, A; Luton, D; Paty, M-C; Ayoubi, J-M; Yazdanpanah, Y; Mandelbrot, L; Matheron, S

2016-05-01

A Zika virus epidemic is currently ongoing in the Americas. This virus is linked to congenital infections with potential severe neurodevelopmental dysfunction. However, incidence of fetal infection and whether this virus is responsible of other fetal complications are still unknown. National and international public health authorities recommend caution and several prevention measures. Declaration of Zika virus infection is now mandatory in France. Given the available knowledge on Zika virus, we suggest here a review of the current recommendations for management of pregnancy in case of suspicious or infection by Zika virus in a pregnant woman. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Computer virus information update CIAC-2301

Energy Technology Data Exchange (ETDEWEB)

Orvis, W.J.

1994-01-15

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.

Biomechanical properties of interosseous proximal carpal row ligaments.

Science.gov (United States)

Nikolopoulos, Fotios; Apergis, Emmanuel; Kefalas, Vassilios; Zoubos, Aristides; Soucacos, Panayiotis; Papagelopoulos, Panayiotis

2011-05-01

The Scapholunate (S-L) and Lunotriquetrum (L-Tr) ligaments have been extensively studied in the literature. A wide range of measurements has been reported for ultimate load and stiffness with different mechanical protocols. In this study, we examined the mechanical properties of both ligaments harvested from the same wrist. Fifteen fresh cadaver wrists were used to harvest eight S-L and four L-Tr. Testing was performed in quasi-static loading in a well defined direction for each ligament system. The ultimate load for S-L was 68-210 N with a mean value of 147 ± 54 N and a stiffness of 35.7 ± 9.6 N/mm. For L-Tr the ultimate load was 122-179 N with a mean value of 150 ± 24 N and a stiffness of 192 ± 60 N/mm. The two ligaments had nearly the same ultimate load, but the L-Tr had a higher stiffness (p = 0.05). These findings could be useful to assess the appropriate autologous autografts for reconstruction of the S-L and L-Tr. Copyright © 2010 Orthopaedic Research Society.

Human immunodeficiency virus and hepatitus B virus co-infection ...

African Journals Online (AJOL)

Human immunodeficiency virus and hepatitus B virus co-infection amog patients in Kano Nigeria. EE Nwokedi, MA Emokpae, AI Dutse. Abstract. No Abstract. Nigerian Journal of Medicine Vol. 15(3) July-September 2006: 227-229. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD ...

Vaccination with Recombinant Parainfluenza Virus 5 Expressing Neuraminidase Protects against Homologous and Heterologous Influenza Virus Challenge.

Science.gov (United States)

Mooney, Alaina J; Gabbard, Jon D; Li, Zhuo; Dlugolenski, Daniel A; Johnson, Scott K; Tripp, Ralph A; He, Biao; Tompkins, S Mark

2017-12-01

Seasonal human influenza virus continues to cause morbidity and mortality annually, and highly pathogenic avian influenza (HPAI) viruses along with other emerging influenza viruses continue to pose pandemic threats. Vaccination is considered the most effective measure for controlling influenza; however, current strategies rely on a precise vaccine match with currently circulating virus strains for efficacy, requiring constant surveillance and regular development of matched vaccines. Current vaccines focus on eliciting specific antibody responses against the hemagglutinin (HA) surface glycoprotein; however, the diversity of HAs across species and antigenic drift of circulating strains enable the evasion of virus-inhibiting antibody responses, resulting in vaccine failure. The neuraminidase (NA) surface glycoprotein, while diverse, has a conserved enzymatic site and presents an appealing target for priming broadly effective antibody responses. Here we show that vaccination with parainfluenza virus 5 (PIV5), a promising live viral vector expressing NA from avian (H5N1) or pandemic (H1N1) influenza virus, elicited NA-specific antibody and T cell responses, which conferred protection against homologous and heterologous influenza virus challenges. Vaccination with PIV5-N1 NA provided cross-protection against challenge with a heterosubtypic (H3N2) virus. Experiments using antibody transfer indicate that antibodies to NA have an important role in protection. These findings indicate that PIV5 expressing NA may be effective as a broadly protective vaccine against seasonal influenza and emerging pandemic threats. IMPORTANCE Seasonal influenza viruses cause considerable morbidity and mortality annually, while emerging viruses pose potential pandemic threats. Currently licensed influenza virus vaccines rely on the antigenic match of hemagglutinin (HA) for vaccine strain selection, and most vaccines rely on HA inhibition titers to determine efficacy, despite the growing

Influenza A virus targets a cGAS-independent STING pathway that controls enveloped RNA viruses.

Science.gov (United States)

Holm, Christian K; Rahbek, Stine H; Gad, Hans Henrik; Bak, Rasmus O; Jakobsen, Martin R; Jiang, Zhaozaho; Hansen, Anne Louise; Jensen, Simon K; Sun, Chenglong; Thomsen, Martin K; Laustsen, Anders; Nielsen, Camilla G; Severinsen, Kasper; Xiong, Yingluo; Burdette, Dara L; Hornung, Veit; Lebbink, Robert Jan; Duch, Mogens; Fitzgerald, Katherine A; Bahrami, Shervin; Mikkelsen, Jakob Giehm; Hartmann, Rune; Paludan, Søren R

2016-02-19

Stimulator of interferon genes (STING) is known be involved in control of DNA viruses but has an unexplored role in control of RNA viruses. During infection with DNA viruses STING is activated downstream of cGAMP synthase (cGAS) to induce type I interferon. Here we identify a STING-dependent, cGAS-independent pathway important for full interferon production and antiviral control of enveloped RNA viruses, including influenza A virus (IAV). Further, IAV interacts with STING through its conserved hemagglutinin fusion peptide (FP). Interestingly, FP antagonizes interferon production induced by membrane fusion or IAV but not by cGAMP or DNA. Similar to the enveloped RNA viruses, membrane fusion stimulates interferon production in a STING-dependent but cGAS-independent manner. Abolishment of this pathway led to reduced interferon production and impaired control of enveloped RNA viruses. Thus, enveloped RNA viruses stimulate a cGAS-independent STING pathway, which is targeted by IAV.

Enhanced light microscopy visualization of virus particles from Zika virus to filamentous ebolaviruses.

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George G Daaboul

Full Text Available Light microscopy is a powerful tool in the detection and analysis of parasites, fungi, and prokaryotes, but has been challenging to use for the detection of individual virus particles. Unlabeled virus particles are too small to be visualized using standard visible light microscopy. Characterization of virus particles is typically performed using higher resolution approaches such as electron microscopy or atomic force microscopy. These approaches require purification of virions away from their normal millieu, requiring significant levels of expertise, and can only enumerate small numbers of particles per field of view. Here, we utilize a visible light imaging approach called Single Particle Interferometric Reflectance Imaging Sensor (SP-IRIS that allows automated counting and sizing of thousands of individual virions. Virions are captured directly from complex solutions onto a silicon chip and then detected using a reflectance interference imaging modality. We show that the use of different imaging wavelengths allows the visualization of a multitude of virus particles. Using Violet/UV illumination, the SP-IRIS technique is able to detect individual flavivirus particles (~40 nm, while green light illumination is capable of identifying and discriminating between vesicular stomatitis virus and vaccinia virus (~360 nm. Strikingly, the technology allows the clear identification of filamentous infectious ebolavirus particles and virus-like particles. The ability to differentiate and quantify unlabeled virus particles extends the usefulness of traditional light microscopy and can be embodied in a straightforward benchtop approach allowing widespread applications ranging from rapid detection in biological fluids to analysis of virus-like particles for vaccine development and production.

Cowpea viruses: Effect of single and mixed infections on symptomatology and virus concentration

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Nsa Imade Y

2007-09-01

Full Text Available Abstract Natural multiple viral infections of cultivated cowpeas have been reported in Nigeria. In this study, three Nigerian commercial cowpea cultivars ("Olo 11", "Oloyin" and "White" and two lines from the IITA (IT86D- 719 and TVU 76 were mechanically inoculated with Cowpea aphid-borne mosaic virus (CABMV, Bean southern mosaic virus (SBMV and Cowpea mottle virus (CMeV singly, as well as in all possible combinations at 10, 20 and 30 days after planting (DAP. Samples of leaves or stems were collected at 10, 20 and 30 days after inoculation (DAI and analyzed for relative virus concentration by Enzyme-Linked Immunosrbent Assay. All the cultivars and lines {CVS/L} were susceptible to the viruses but the commercial CVS showed more severe symptoms and had relatively higher viral concentration. In single virus infections, CABMV which induced the most severe symptoms had absorbance values (at 405 nm of 0.11 to 0.46 while SBMV and CMeV which induced moderate symptoms had virus titre of 0.74 to 1.99 and 0.11 to 0.90 respectively. Plants inoculated 10 DAP had significantly higher virus concentration than those inoculated 30 DAP. In mixed infections involving CABMV (10 DAP apical necrosis and death were observed in commercial cultivars "Olo 11" and "White". Enhancement of CMeV titers were observed in plants infected with CMeV + CABMV. Multiple viral infections of cowpeas may result in complete yield loss, hence, the availability of seeds of cultivars with a high level of multiple virus resistance is recommended as a means of control.

Genome Sequence of Bivens Arm Virus, a Tibrovirus Belonging to the Species Tibrogargan virus (Mononegavirales: Rhabdoviridae).

Science.gov (United States)

Lauck, Michael; Yú, Shu Qìng; Caì, Yíngyún; Hensley, Lisa E; Chiu, Charles Y; O'Connor, David H; Kuhn, Jens H

2015-03-19

The new rhabdoviral genus Tibrovirus currently has two members, Coastal Plains virus and Tibrogargan virus. Here, we report the coding-complete genome sequence of a putative member of this genus, Bivens Arm virus. A genomic comparison reveals Bivens Arm virus to be closely related to, but distinct from, Tibrogargan virus. Copyright © 2015 Lauck et al.

Replication and clearance of respiratory syncytial virus - Apoptosis is an important pathway of virus clearance after experimental infection with bovine respiratory syncytial virus

DEFF Research Database (Denmark)

Viuff, B.; Tjørnehøj, Kirsten; Larsen, Lars Erik

2002-01-01

and clearance in a natural target animal. Replication of BRSV was demonstrated in the luminal part of the respiratory epithelial cells and replication in the upper respiratory tract preceded the replication in the lower respiratory tract. Virus excreted to the lumen of the respiratory tract was cleared...... and the infections with human respiratory syncytial. virus and BRSV have similar clinical, pathological, and epidemiological characteristics. In this study we used experimental BRSV infection in calves as a model of respiratory syncytial virus infection to demonstrate important aspects of viral replication......Human respiratory syncytial virus is an important cause of severe respiratory disease in young children, the elderly, and in immunocompromised adults. Similarly, bovine respiratory syncytial virus (BRSV) is causing severe, sometimes fatal, respiratory disease in calves. Both viruses are pneumovirus...

CMV-Promoter Driven Codon-Optimized Expression Alters the Assembly Type and Morphology of a Reconstituted HERV-K(HML-2

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Oliver Hohn

2014-11-01

Full Text Available The HERV-K(HML-2 family contains the most recently integrated and best preserved endogenized proviral sequences in the human genome. All known elements have nevertheless been subjected to mutations or deletions that render expressed particles non-infectious. Moreover, these post-insertional mutations hamper the analysis of the general biological properties of this ancient virus family. The expression of consensus sequences and sequences of elements with reverted post-insertional mutations has therefore been very instrumental in overcoming this limitation. We investigated the particle morphology of a recently reconstituted HERV-K113 element termed oriHERV-K113 using thin-section electron microscopy (EM and could demonstrate that strong overexpression by substitution of the 5'LTR for a CMV promoter and partial codon optimization altered the virus assembly type and morphology. This included a conversion from the regular C-type to an A-type morphology with a mass of cytoplasmic immature cores tethered to the cell membrane and the membranes of vesicles. Overexpression permitted the release and maturation of virions but reduced the envelope content. A weaker boost of virus expression by Staufen-1 was not sufficient to induce these morphological alterations.

CMV-promoter driven codon-optimized expression alters the assembly type and morphology of a reconstituted HERV-K(HML-2).

Science.gov (United States)

Hohn, Oliver; Hanke, Kirsten; Lausch, Veronika; Zimmermann, Anja; Mostafa, Saeed; Bannert, Norbert

2014-11-11

The HERV-K(HML-2) family contains the most recently integrated and best preserved endogenized proviral sequences in the human genome. All known elements have nevertheless been subjected to mutations or deletions that render expressed particles non-infectious. Moreover, these post-insertional mutations hamper the analysis of the general biological properties of this ancient virus family. The expression of consensus sequences and sequences of elements with reverted post-insertional mutations has therefore been very instrumental in overcoming this limitation. We investigated the particle morphology of a recently reconstituted HERV-K113 element termed oriHERV-K113 using thin-section electron microscopy (EM) and could demonstrate that strong overexpression by substitution of the 5'LTR for a CMV promoter and partial codon optimization altered the virus assembly type and morphology. This included a conversion from the regular C-type to an A-type morphology with a mass of cytoplasmic immature cores tethered to the cell membrane and the membranes of vesicles. Overexpression permitted the release and maturation of virions but reduced the envelope content. A weaker boost of virus expression by Staufen-1 was not sufficient to induce these morphological alterations.

Temporal Analysis of Andes Virus and Sin Nombre Virus Infections of Syrian Hamsters

Science.gov (United States)

2007-05-01

Microbiology . All Rights Reserved. Temporal Analysis of Andes Virus and Sin Nombre Virus Infections of Syrian Hamsters Victoria Wahl-Jensen,1 Jennifer...Ye, C., J. Prescott , R. Nofchissey, D. Goade, and B. Hjelle. 2004. Neutralizing antibodies and Sin Nombre virus RNA after recovery from hantavirus

Monitoring virus entry into living cells using DiD-labeled dengue virus particles

NARCIS (Netherlands)

Ayala Nunez, Vanesa; Wilschut, Jan; Smit, Jolanda M.

2011-01-01

A variety of approaches can be applied to investigate the multiple steps and interactions that occur during virus entry into the host cell. Single-virus tracking is a powerful real-time imaging technique that offers the possibility to monitor virus-cell binding, internalization, intracellular

Neutralizing antibodies against flaviviruses, Babanki virus, and Rift Valley fever virus in Ugandan bats.

Science.gov (United States)

Kading, Rebekah C; Kityo, Robert M; Mossel, Eric C; Borland, Erin M; Nakayiki, Teddie; Nalikka, Betty; Nyakarahuka, Luke; Ledermann, Jeremy P; Panella, Nicholas A; Gilbert, Amy T; Crabtree, Mary B; Peterhans, Julian Kerbis; Towner, Jonathan S; Amman, Brian R; Sealy, Tara K; Nichol, Stuart T; Powers, Ann M; Lutwama, Julius J; Miller, Barry R

2018-01-01

Introduction: A number of arboviruses have previously been isolated from naturally-infected East African bats, however the role of bats in arbovirus maintenance is poorly understood. The aim of this study was to investigate the exposure history of Ugandan bats to a panel of arboviruses. Materials and methods: Insectivorous and fruit bats were captured from multiple locations throughout Uganda during 2009 and 2011-2013. All serum samples were tested for neutralizing antibodies against West Nile virus (WNV), yellow fever virus (YFV), dengue 2 virus (DENV-2), Zika virus (ZIKV), Babanki virus (BBKV), and Rift Valley fever virus (RVFV) by plaque reduction neutralization test (PRNT). Sera from up to 626 bats were screened for antibodies against each virus. Results and Discussion:  Key findings include the presence of neutralizing antibodies against RVFV in 5/52 (9.6%) of little epauletted fruit bats ( Epomophorus labiatus ) captured from Kawuku and 3/54 (5.6%) Egyptian rousette bats from Kasokero cave. Antibodies reactive to flaviviruses were widespread across bat taxa and sampling locations. Conclusion: The data presented demonstrate the widespread exposure of bats in Uganda to arboviruses, and highlight particular virus-bat associations that warrant further investigation.

Seasonal Dynamics of Haptophytes and dsDNA Algal Viruses Suggest Complex Virus-Host Relationship.

Science.gov (United States)

Johannessen, Torill Vik; Larsen, Aud; Bratbak, Gunnar; Pagarete, António; Edvardsen, Bente; Egge, Elianne D; Sandaa, Ruth-Anne

2017-04-20

Viruses influence the ecology and diversity of phytoplankton in the ocean. Most studies of phytoplankton host-virus interactions have focused on bloom-forming species like Emiliania huxleyi or Phaeocystis spp. The role of viruses infecting phytoplankton that do not form conspicuous blooms have received less attention. Here we explore the dynamics of phytoplankton and algal viruses over several sequential seasons, with a focus on the ubiquitous and diverse phytoplankton division Haptophyta, and their double-stranded DNA viruses, potentially with the capacity to infect the haptophytes. Viral and phytoplankton abundance and diversity showed recurrent seasonal changes, mainly explained by hydrographic conditions. By 454 tag-sequencing we revealed 93 unique haptophyte operational taxonomic units (OTUs), with seasonal changes in abundance. Sixty-one unique viral OTUs, representing Megaviridae and Phycodnaviridae , showed only distant relationship with currently isolated algal viruses. Haptophyte and virus community composition and diversity varied substantially throughout the year, but in an uncoordinated manner. A minority of the viral OTUs were highly abundant at specific time-points, indicating a boom-bust relationship with their host. Most of the viral OTUs were very persistent, which may represent viruses that coexist with their hosts, or able to exploit several host species.

Reference gene selection for quantitative real-time PCR analysis in virus infected cells: SARS corona virus, Yellow fever virus, Human Herpesvirus-6, Camelpox virus and Cytomegalovirus infections

Directory of Open Access Journals (Sweden)

Müller Marcel A

2005-02-01

Full Text Available Abstract 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 tool and by criteria we reported previously. Ranking lists of the genes tested were tool dependent. However, over all, β-actin is an unsuitable as reference gene, whereas TATA-Box binding protein and peptidyl-prolyl-isomerase A are stable reference genes for expression studies in virus infected cells.

Filovirus pathogenesis and immune evasion: insights from Ebola virus and Marburg virus

Energy Technology Data Exchange (ETDEWEB)

Messaoudi, Ilhem; Amarasinghe, Gaya K.; Basler, Christopher F.

2015-10-06

Ebola viruses and Marburg viruses, members of the filovirus family, are zoonotic pathogens that cause severe disease in people, as highlighted by the latest Ebola virus epidemic in West Africa. Filovirus disease is characterized by uncontrolled virus replication and the activation of host responses that contribute to pathogenesis. Underlying these phenomena is the potent suppression of host innate antiviral responses, particularly the type I interferon response, by viral proteins, which allows high levels of viral replication. In this Review, we describe the mechanisms used by filoviruses to block host innate immunity and discuss the links between immune evasion and filovirus pathogenesis.

PREFACE The physics of virus assembly The physics of virus assembly

Science.gov (United States)

Stockley, Peter G.; Twarock, Reidun

2010-12-01

Viruses are pathogens in every kingdom of life and are major causes of human disease and suffering. They are known to encompass a size range that overlaps with that of the smallest bacterial cells, and the largest viruses now seem to be hosts of their own viral pathogens. Recent genomic sequencing efforts show that many organisms have genes that are likely to be descended in evolution from viral progenitors. Even more astonishingly, analysis of the world's oceans has shown that some of the simplest viruses, the tailed dsDNA phages, are the most common biological entities on the planet, with estimates of their numbers ranging up to 1031, with ~ 1021 infection events every second, leading to a turnover of around 20% of the biomass in the sea every few days. These cycles of infection and lysis of oceanic bacteria and algae provide the nutrients for the smallest organisms lying at the bottom of the food chain. Without viruses, therefore, life on Earth would probably not be sustainable. These are remarkable facts for systems that are non-living in the strict sense, and are composed of simple materials—nucleic acids, proteins and lipids. Many viruses consist of little more than a protective protein coat surrounding their genomic nucleic acids, which can be either DNA or RNA. Their simplicity leads to highly symmetrical structures with protein containers based on helical or icosahedral lattices. Many simple viruses self-assemble rapidly and with great fidelity, and many groups are busy trying to exploit these properties to make virus-like particles for a wide range of applications, including targeted drug-delivery, medical imaging and even novel materials. This issue of Physical Biology contains a series of papers describing some of the latest experimental and theoretical research on viruses, their structures and assembly, as well as their regulated disassembly during infection. These range from a dissection of the in vivo assembly mechanism of a filamentous virus

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

Science.gov (United States)

Primich, Tracy

1992-01-01

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)

Presence and Distribution of Oilseed Pumpkin Viruses and Molecular Detection of Zucchini Yellow Mosaic Virus

Directory of Open Access Journals (Sweden)

Ana Vučurović

2009-01-01

Full Text Available Over the past decade, intensive spread of virus infections of oilseed pumpkin has resulted in significant economic losses in pumpkin crop production, which is currently expanding in our country. In 2007 and 2008, a survey for the presence and distribution of oilseed pumpkin viruses was carried out in order to identify viruses responsible for epidemics and incidences of very destructive symptoms on cucurbit leaves and fruits. Monitoring andcollecting samples of oil pumpkin, as well as other species such as winter and butternut squash and buffalo and bottle gourd with viral infection symptoms, was conducted in several localities of Vojvodina Province. The collected plant samples were tested by DAS-ELISA using polyclonal antisera specific for the detection of six most economically harmful pumpkin viruses: Cucumber mosaic virus (CMV, Zucchini yellow mosaic virus (ZYMV, Watermelon mosaic virus (WMW, Squash mosaic virus (SqMV, Papaya ringspot virus (PRSV and Tobaccoringspot virus (TRSV that are included in A1 quarantine list of harmful organisms in Serbia.Identification of viruses in the collected samples indicated the presence of three viruses, ZYMV, WMV and CMV, in individual and mixed infections. Frequency of the identified viruses varied depending on locality and year of investigations. In 2007, WMV was the most frequent virus (94.2%, while ZYMV was prevalent (98.04% in 2008. High frequency of ZYMV determined in both years of investigation indicated the need for its rapid and reliable molecular detection. During this investigation, a protocol for ZYMVdetection was developed and optimized using specific primers CPfwd/Cprev and commercial kits for total RNA extraction, as well as for RT-PCR. In RT-PCR reaction using these primers, a DNA fragment of approximately 1100 bp, which included coat protein gene, was amplified in the samples of infected pumkin leaves. Although serological methods are still useful for large-scale testing of a great number of

Archaeal virus-host interactions

NARCIS (Netherlands)

Quax, T.E.F.

2013-01-01

The work presented in this thesis provides novel insights in several aspects of the molecular

biology of archaea, bacteria and their viruses.

Three fundamentally different groups of viruses are associated with the three domains of life.

Archaeal viruses are

Prevalence of hepatitis A virus, hepatitis B virus, hepatitis C virus, hepatitis D virus and hepatitis E virus as causes of acute viral hepatitis in North India: a hospital based study.

Science.gov (United States)

Jain, P; Prakash, S; Gupta, S; Singh, K P; Shrivastava, S; Singh, D D; Singh, J; Jain, A

2013-01-01

Acute viral hepatitis (AVH) is a major public health problem and is an important cause of morbidity and mortality. The aim of the present study is to determine the prevalence of hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV) and hepatitis E virus (HEV) as causes of AVH in a tertiary care hospital of North India. Blood samples and clinical information was collected from cases of AVH referred to the Grade I viral diagnostic laboratory over a 1-year period. Samples were tested for hepatitis B surface antigen, anti-HCV total antibodies, anti-HAV immunoglobulin M (IgM) and anti-HEV IgM by the enzyme-linked immunosorbent assay. PCR for nucleic acid detection of HBV and HCV was also carried out. Those positive for HBV infection were tested for anti-HDV antibodies. Fisher's exact test was used and a P hepatitis cases, 62 (23.22%) patients presented as acute hepatic failure. HAV (26.96%) was identified as the most common cause of acute hepatitis followed by HEV (17.97%), HBV (16.10%) and HCV (11.98%). Co-infections with more than one virus were present in 34 cases; HAV-HEV co-infection being the most common. HEV was the most important cause of acute hepatic failure followed by co-infection with HAV and HEV. An indication towards epidemiological shift of HAV infection from children to adults with a rise in HAV prevalence was seen. To the best of our knowledge, this is the first report indicating epidemiological shift of HAV in Uttar Pradesh.

Epstein-Barr virus, human papillomavirus and mouse mammary tumour virus as multiple viruses in breast cancer.

Science.gov (United States)

Glenn, Wendy K; Heng, Benjamin; Delprado, Warick; Iacopetta, Barry; Whitaker, Noel J; Lawson, James S

2012-01-01

The purpose of this investigation is to determine if Epstein Barr virus (EBV), high risk human papillomavirus (HPV), and mouse mammary tumour viruses (MMTV) co-exist in some breast cancers. All the specimens were from women residing in Australia. For investigations based on standard PCR, we used fresh frozen DNA extracts from 50 unselected invasive breast cancers. For normal breast specimens, we used DNA extracts from epithelial cells from milk donated by 40 lactating women. For investigations based on in situ PCR we used 27 unselected archival formalin fixed breast cancer specimens and 18 unselected archival formalin fixed normal breast specimens from women who had breast reduction surgery. Thirteen of these fixed breast cancer specimens were ductal carcinoma in situ (dcis) and 14 were predominantly invasive ductal carcinomas (idc). EBV sequences were identified in 68%, high risk HPV sequences in 50%, and MMTV sequences in 78% of DNA extracted from 50 invasive breast cancer specimens. These same viruses were identified in selected normal and breast cancer specimens by in situ PCR. Sequences from more than one viral type were identified in 72% of the same breast cancer specimens. Normal controls showed these viruses were also present in epithelial cells in human milk - EBV (35%), HPV, 20%) and MMTV (32%) of 40 milk samples from normal lactating women, with multiple viruses being identified in 13% of the same milk samples. We conclude that (i) EBV, HPV and MMTV gene sequences are present and co-exist in many human breast cancers, (ii) the presence of these viruses in breast cancer is associated with young age of diagnosis and possibly an increased grade of breast cancer.

Inhibition of Interferon Induction and Action by the Nairovirus Nairobi Sheep Disease Virus/Ganjam Virus

OpenAIRE

Holzer, Barbara; Bakshi, Siddharth; Bridgen, Anne; Baron, Michael D.

2011-01-01

The Nairoviruses are an important group of tick-borne viruses that includes pathogens of man (Crimean Congo hemorrhagic fever virus) and livestock animals (Dugbe virus, Nairobi sheep disease virus (NSDV)). NSDV is found in large parts of East Africa and the Indian subcontinent (where it is known as Ganjam virus). We have investigated the ability of NSDV to antagonise the induction and actions of interferon. Both pathogenic and apathogenic isolates could actively inhibit the induction of type ...

Characterization of Ebola Virus Entry by Using Pseudotyped Viruses: Identification of Receptor-Deficient Cell Lines

OpenAIRE

Wool-Lewis, Rouven J.; Bates, Paul

1998-01-01

Studies analyzing Ebola virus replication have been severely hampered by the extreme pathogenicity of this virus. To permit analysis of the host range and function of the Ebola virus glycoprotein (Ebo-GP), we have developed a system for pseudotyping these glycoproteins into murine leukemia virus (MLV). This pseudotyped virus, MLV(Ebola), can be readily concentrated to titers which exceed 5 × 106 infectious units/ml and is effectively neutralized by antibodies specific for Ebo-GP. Analysis of ...

Das Epstein-Barr-Virus ( = Epstein-Barr virus)

OpenAIRE

Niller, H. H.; Wolf, Hans J.

1993-01-01

Epstein-Barr virus is an ubiquitous humanpathogenic herpesvirus. It has been identified as the etiologic agent of infectious mononucleosis. In addition it is associated with the cancers nasopharyngeal carcinoma and Burkitt's lymphoma. Like other herpesviruses it infects cells in a lytic way or it persists in a latent state. Classically, the serologic diagnosis of Epstein-Barr virus infections is done by the agglutination of sheep erythrocytes according to Paul and Bunnell as a rapid testing m...

[Viruses and civilization].

Science.gov (United States)

Chastel, C

1999-01-01

A few million years ago, when primates moved from the east African forest to the savannah, they were already infected with endogenous viruses and occultly transmitted them to the prime Homo species. However it was much later with the building of the first large cities in Mesopotamia that interhuman viral transmission began in earnest. Spreading was further enhanced with the organization of the Egyptian, Greek, Roman, and Arab empires around the Mediterranean. Discovery of the New World in 1492 led to an unprecedented clash of civilizations and the destruction of pre-Columbian Indian civilizations. It also led to a rapid spread of viruses across the Atlantic Ocean with the emergence of yellow fever and appearance of smallpox and measles throughout the world. However the greatest opportunities for worldwide viral development have been created by our present, modern civilization. This fact is illustrated by epidemic outbreaks of human immunodeficiency virus, Venezuela hemorrhagic fever, Rift valley fever virus, and monkey pox virus. Close analysis underscores the major role of human intervention in producing these events.

Comparative analysis of rabbit hemorrhagic disease virus (RHDV) and new RHDV2 virus antigenicity, using specific virus-like particles

OpenAIRE

Bárcena, Juan; Guerra, Beatriz; Angulo, Iván; González, Julia; Valcárcel, Félix; Mata, Carlos P.; Castón, José R.; Blanco, Esther; Alejo, Alí

2015-01-01

International audience; In 2010 a new Lagovirus related to rabbit haemorrhagic disease virus (RHDV) emerged in France and has since rapidly spread throughout domestic and wild rabbit populations of several European countries. The new virus, termed RHDV2, exhibits distinctive genetic, antigenic and pathogenic features. Notably, RHDV2 kills rabbits previously vaccinated with RHDV vaccines. Here we report for the first time the generation and characterization of RHDV2-specific virus-like particl...

RECOVIR Software for Identifying Viruses

Science.gov (United States)

Chakravarty, Sugoto; Fox, George E.; Zhu, Dianhui

2013-01-01

Most single-stranded RNA (ssRNA) viruses mutate rapidly to generate a large number of strains with highly divergent capsid sequences. Determining the capsid residues or nucleotides that uniquely characterize these strains is critical in understanding the strain diversity of these viruses. RECOVIR (an acronym for "recognize viruses") software predicts the strains of some ssRNA viruses from their limited sequence data. Novel phylogenetic-tree-based databases of protein or nucleic acid residues that uniquely characterize these virus strains are created. Strains of input virus sequences (partial or complete) are predicted through residue-wise comparisons with the databases. RECOVIR uses unique characterizing residues to identify automatically strains of partial or complete capsid sequences of picorna and caliciviruses, two of the most highly diverse ssRNA virus families. Partition-wise comparisons of the database residues with the corresponding residues of more than 300 complete and partial sequences of these viruses resulted in correct strain identification for all of these sequences. This study shows the feasibility of creating databases of hitherto unknown residues uniquely characterizing the capsid sequences of two of the most highly divergent ssRNA virus families. These databases enable automated strain identification from partial or complete capsid sequences of these human and animal pathogens.

Hepatitis virus panel

Science.gov (United States)

... page: //medlineplus.gov/ency/article/003558.htm Hepatitis virus panel To use the sharing features on this page, please enable JavaScript. The hepatitis virus panel is a series of blood tests used ...

Polyomavirus specific cellular immunity: from BK-virus-specific cellular immunity to BK-virus-associated nephropathy ?

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manon edekeyser

2015-06-01

Full Text Available In renal transplantation, BK-virus-associated nephropathy has emerged as a major complication, with a prevalence of 5–10% and graft loss in >50% of cases. BK-virus is a member of the Polyomavirus family and rarely induces apparent clinical disease in the general population. However, replication of polyomaviruses, associated with significant organ disease, is observed in patients with acquired immunosuppression, which suggests a critical role for virus-specific cellular immunity to control virus replication and prevent chronic disease. Monitoring of specific immunity combined with viral load could be used to individually assess the risk of viral reactivation and virus control. We review the current knowledge on BK-virus specific cellular immunity and, more specifically, in immunocompromised patients. In the future, immune-based therapies could allow us to treat and prevent BK-virus-associated nephropathy.

Outbreaks of influenza A virus in farmed mink (Neovison vison) in Denmark: molecular characterization of the viruses

DEFF Research Database (Denmark)

Larsen, Lars Erik; Breum, Solvej Østergaard; Trebbien, Ramona

2012-01-01

that the virus was a human/swine reassortant, with the H and N gene most related to human H3N2 viruses circulating in 2005. The remaining 6 genes were most closely related to H1N2 influenza viruses circulating in Danish swine. This virus had not previously been described in swine, mink or humans. PCRs assays...... specifically targeting the new reassortant were developed and used to screen influenza positive samples from humans and swine in Denmark with negative results. Thus, there was no evidence that this virus had spread to humans or was circulating in Danish pigs. In 2010 and 2011, influenza virus was again...... diagnosed in diseased mink in a few farms. The genetic typing showed that the virus was similar to the pandemic H1N1 virus circulating in humans and swine. The H3N2 virus was not detected in 2010 and 2011. Taken together, these findings indicate that mink is highly susceptible for influenza A virus of human...

Diversity of viruses in Ixodes ricinus, and characterization of a neurotropic strain of Eyach virus

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S. Moutailler

2016-05-01

Full Text Available Ticks transmit more pathogens—including bacteria, parasites and viruses—than any other arthropod vector. Although the epidemiological status of many tick-borne bacteria is very well characterized, tick-borne viruses are still relatively under-studied. Recently, several novel tick-borne viruses have been isolated from human febrile illnesses following tick bites, indicating the existence of other potential new and unknown tick-borne viruses. We used high-throughput sequencing to analyse the virome of Ixodes ricinus, the main vector of tick-borne pathogens in Europe. The majority of collected viral sequences were assigned to two potentially novel Nairovirus and Phlebovirus viruses, with prevalence rates ranging from 3.95% to 23.88% in adults and estimated to be between 0.14% and 72.16% in nymphs. These viruses could not be isolated from the brains of inoculated immunocompromised mice, perhaps indicating that they are unable to infect vertebrates. Within the I. ricinus virome, we also identified contigs with >90% identity to the known Eyach virus. Initially isolated in the 1980s, this virus was indirectly associated with human disease, but had never been extensively studied. Eyach virus prevalence varied between 0.07% and 5.26% in ticks from the French Ardennes and Alsace regions. Eyach virus was successfully isolated following intracerebral inoculation of immunocompromised mice with Eyach virus-positive tick extracts. This virus was also able to multiply and persist in the blood of immunocompetent mice inoculated by intraperitoneal injection, and caused brain infections in three of nine juveniles, without any obvious deleterious effects.

Analysis of proteins of mouse sarcoma pseudotype viruses: type-specific radioimmunoassays for ecotropic virus p30's

International Nuclear Information System (INIS)

Kennel, S.J.; Tennant, R.W.

1979-01-01

Murine sarcoma virus pseudotypes were prepared by infection of nonproducer cells (A1-2), which were transformed by the Gazdar strain of mouse sarcoma virus, with Gross (N-tropic), WN1802B (B-tropic), or Moloney (NB-tropic) viruses. The respective host range pseudotype sarcoma viruses were defined by the tritration characteristics on cells with the appropriate Fv-1 genotype. Proteins from virus progeny were analyzed by sodium dodecyl sulfate--polyacrylamide gel electrophoresis. Bands present in both the 65,000- and the 10,000- to 20,000-molecular-weight regions of the gel distinguished the pseudotype viruses from their respective helpers. Furthermore, two protein bands were noted in the p30 region of murine sarcoma virus (Gross), one corresponding to Gross virus p30, and another of slightly slower mobility. However, since the mobility of the putative sarcoma p30 is nearly indentical to that of WN1802B, its presence could not be established by sodium dodecyl sulfate--polyacrylamide gel electrophoresis. Type-specific radioimmunossays for Gross virus p30 and for WN1802B p30 were applied for analysis of pseudotype preparations, and among several ecotropic viruses tested, only the homologous virus scored in the respective assay. By use of these assays, pseudotype viruses were found to contain only 8 to 48% helper-specific p30's; the remainder is presumably derived from the sarcoma virus

Characteristic of pandemic virus

Indian Academy of Sciences (India)

First page Back Continue Last page Graphics. Characteristic of pandemic virus. The virus was highly transmissible. Risk of hospitalization was 2X and risk of death was about 11X more in comparison to seasonal influenza. Virus continues to be susceptible to Osaltamivir, the only drug available. Vaccines are available but ...

Avian influenza viruses in humans.

Science.gov (United States)

Malik Peiris, J S

2009-04-01

Past pandemics arose from low pathogenic avian influenza (LPAI) viruses. In more recent times, highly pathogenic avian influenza (HPAI) H5N1, LPAI H9N2 and both HPAI and LPAI H7 viruses have repeatedly caused zoonotic disease in humans. Such infections did not lead to sustained human-to-human transmission. Experimental infection of human volunteers and seroepidemiological studies suggest that avian influenza viruses of other subtypes may also infect humans. Viruses of the H7 subtype appear to have a predilection to cause conjunctivitis and influenza-like illness (ILI), although HPAI H7N7 virus has also caused fatal respiratory disease. Low pathogenic H9N2 viruses have caused mild ILI and its occurrence may be under-recognised for this reason. In contrast, contemporary HPAI H5N1 viruses are exceptional in their virulence for humans and differ from human seasonal influenza viruses in their pathogenesis. Patients have a primary viral pneumonia progressing to acute respiratory distress syndrome (ARDS) and multiple organ dysfunction syndrome. Over 380 human cases have been confirmed to date, with an overall case fatality of 63%. The zoonotic transmission of avian influenza is a rare occurrence, butthe greater public health concern is the adaptation of such viruses to efficient human transmission, which could lead to a pandemic. A better understanding of the ecology of avian influenza viruses and the biological determinants of transmissibility and pathogenicity in humans is important for pandemic preparedness.

Zika virus infection: a public health emergency!

OpenAIRE

Qureshi, Muhammad Salman Haider; Qureshi, Bakhtawar Wajeeha; Khan, Ramsha

2017-01-01

Zika virus belongs to the family of Flaviviridae. The Flaviviridae family also includes other human pathogens like West Nile virus (WNV), Yellow fever virus (YFV), mosquito transmitted Dengue virus (DENV), Tick borne encephalitic virus (TBEV) and Japanese encephalitis virus (JEV). Zika virus is a mosquito-borne disease and is transmitted by Aedes aegypti mosquito.

Human Parainfluenza Viruses

Science.gov (United States)

... Search Form Controls Cancel Submit Search The CDC Human Parainfluenza Viruses (HPIVs) Note: Javascript is disabled or ... CDC.gov . Recommend on Facebook Tweet Share Compartir Human parainfluenza viruses (HPIVs) commonly cause respiratory illnesses in ...

Respiratory Syncytial Virus

Science.gov (United States)

... with facebook share with twitter share with linkedin Respiratory Syncytial Virus (RSV) Credit: CDC This is the ... the United States. Why Is the Study of Respiratory Syncytial Virus (RSV) a Priority for NIAID? In ...

Antiviral Activity of Sukomycin Against Potato Virus Y And Tomato Mosaic Virus

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Nikolay Petrov

2016-12-01

Full Text Available Potato virus Y (PVY and Tomato mosaic virus (ToMV are one of the most important plant viruses that strongly influence the quality and quantity of vegetable production and cause substantial losses to farmers. The most convetional and common method of pest and disease control is trough the use of pesticides. Unfortunately, most of them are synthetic compounds without antiviral activities and possess inherent toxicities that endanger the health of the farm operators, consumers and the environment. In order to carry out a control of viral infections in plants and to reduce the loss of production it is necessary the search for alternative and environmentally friendly methods for control. Sukomycin is a complex of substances with antimicrobial and antiviral activities produced from Streptomyces hygroscopicus isolated from soil. This natural complex reduces significantly symptoms and DAS-ELISA values of Potato virus Y and Tomato mosaic virus in tobacco plants.

Prevention of Hepatitis B Virus and Hepatitis C Virus Transmission ...

African Journals Online (AJOL)

Introduction: Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections in hemodialysis (HD) patients are associated with adverse outcomes, especially after kidney transplantation. Review: In the HD setting, cross-contamination to patients via environmental surfaces, supplies, equipment, multiple-dose medication vials ...

A fusion-inhibiting peptide against Rift Valley fever virus inhibits multiple, diverse viruses.

Directory of Open Access Journals (Sweden)

Jeffrey W Koehler

Full Text Available For enveloped viruses, fusion of the viral envelope with a cellular membrane is critical for a productive infection to occur. This fusion process is mediated by at least three classes of fusion proteins (Class I, II, and III based on the protein sequence and structure. For Rift Valley fever virus (RVFV, the glycoprotein Gc (Class II fusion protein mediates this fusion event following entry into the endocytic pathway, allowing the viral genome access to the cell cytoplasm. Here, we show that peptides analogous to the RVFV Gc stem region inhibited RVFV infectivity in cell culture by inhibiting the fusion process. Further, we show that infectivity can be inhibited for diverse, unrelated RNA viruses that have Class I (Ebola virus, Class II (Andes virus, or Class III (vesicular stomatitis virus fusion proteins using this single peptide. Our findings are consistent with an inhibition mechanism similar to that proposed for stem peptide fusion inhibitors of dengue virus in which the RVFV inhibitory peptide first binds to both the virion and cell membranes, allowing it to traffic with the virus into the endocytic pathway. Upon acidification and rearrangement of Gc, the peptide is then able to specifically bind to Gc and prevent fusion of the viral and endocytic membranes, thus inhibiting viral infection. These results could provide novel insights into conserved features among the three classes of viral fusion proteins and offer direction for the future development of broadly active fusion inhibitors.

Inactivated Recombinant Rabies Viruses Displaying Canine Distemper Virus Glycoproteins Induce Protective Immunity against Both Pathogens.

Science.gov (United States)

da Fontoura Budaszewski, Renata; Hudacek, Andrew; Sawatsky, Bevan; Krämer, Beate; Yin, Xiangping; Schnell, Matthias J; von Messling, Veronika

2017-04-15

The development of multivalent vaccines is an attractive methodology for the simultaneous prevention of several infectious diseases in vulnerable populations. Both canine distemper virus (CDV) and rabies virus (RABV) cause lethal disease in wild and domestic carnivores. While RABV vaccines are inactivated, the live-attenuated CDV vaccines retain residual virulence for highly susceptible wildlife species. In this study, we developed recombinant bivalent vaccine candidates based on recombinant vaccine strain rabies virus particles, which concurrently display the protective CDV and RABV glycoprotein antigens. The recombinant viruses replicated to near-wild-type titers, and the heterologous glycoproteins were efficiently expressed and incorporated in the viral particles. Immunization of ferrets with beta-propiolactone-inactivated recombinant virus particles elicited protective RABV antibody titers, and animals immunized with a combination of CDV attachment protein- and fusion protein-expressing recombinant viruses were protected from lethal CDV challenge. However, animals that were immunized with only a RABV expressing the attachment protein of CDV vaccine strain Onderstepoort succumbed to infection with a more recent wild-type strain, indicating that immune responses to the more conserved fusion protein contribute to protection against heterologous CDV strains. IMPORTANCE Rabies virus and canine distemper virus (CDV) cause high mortality rates and death in many carnivores. While rabies vaccines are inactivated and thus have an excellent safety profile and high stability, live-attenuated CDV vaccines can retain residual virulence in highly susceptible species. Here we generated recombinant inactivated rabies viruses that carry one of the CDV glycoproteins on their surface. Ferrets immunized twice with a mix of recombinant rabies viruses carrying the CDV fusion and attachment glycoproteins were protected from lethal CDV challenge, whereas all animals that received

Archaeal Viruses from High-Temperature Environments.

Science.gov (United States)

Munson-McGee, Jacob H; Snyder, Jamie C; Young, Mark J

2018-02-27

Archaeal viruses are some of the most enigmatic viruses known, due to the small number that have been characterized to date. The number of known archaeal viruses lags behind known bacteriophages by over an order of magnitude. Despite this, the high levels of genetic and morphological diversity that archaeal viruses display has attracted researchers for over 45 years. Extreme natural environments, such as acidic hot springs, are almost exclusively populated by Archaea and their viruses, making these attractive environments for the discovery and characterization of new viruses. The archaeal viruses from these environments have provided insights into archaeal biology, gene function, and viral evolution. This review focuses on advances from over four decades of archaeal virology, with a particular focus on archaeal viruses from high temperature environments, the existing challenges in understanding archaeal virus gene function, and approaches being taken to overcome these limitations.

Archaeal Viruses from High-Temperature Environments

Directory of Open Access Journals (Sweden)

Jacob H. Munson-McGee

2018-02-01

Full Text Available Archaeal viruses are some of the most enigmatic viruses known, due to the small number that have been characterized to date. The number of known archaeal viruses lags behind known bacteriophages by over an order of magnitude. Despite this, the high levels of genetic and morphological diversity that archaeal viruses display has attracted researchers for over 45 years. Extreme natural environments, such as acidic hot springs, are almost exclusively populated by Archaea and their viruses, making these attractive environments for the discovery and characterization of new viruses. The archaeal viruses from these environments have provided insights into archaeal biology, gene function, and viral evolution. This review focuses on advances from over four decades of archaeal virology, with a particular focus on archaeal viruses from high temperature environments, the existing challenges in understanding archaeal virus gene function, and approaches being taken to overcome these limitations.

A Foxtail mosaic virus Vector for Virus-Induced Gene Silencing in Maize1[OPEN

Science.gov (United States)

Mei, Yu; Kernodle, Bliss M.; Hill, John H.

2016-01-01

Plant viruses have been widely used as vectors for foreign gene expression and virus-induced gene silencing (VIGS). A limited number of viruses have been developed into viral vectors for the purposes of gene expression or VIGS in monocotyledonous plants, and among these, the tripartite viruses Brome mosaic virus and Cucumber mosaic virus have been shown to induce VIGS in maize (Zea mays). We describe here a new DNA-based VIGS system derived from Foxtail mosaic virus (FoMV), a monopartite virus that is able to establish systemic infection and silencing of endogenous maize genes homologous to gene fragments inserted into the FoMV genome. To demonstrate VIGS applications of this FoMV vector system, four genes, phytoene desaturase (functions in carotenoid biosynthesis), lesion mimic22 (encodes a key enzyme of the porphyrin pathway), iojap (functions in plastid development), and brown midrib3 (caffeic acid O-methyltransferase), were silenced and characterized in the sweet corn line Golden × Bantam. Furthermore, we demonstrate that the FoMV infectious clone establishes systemic infection in maize inbred lines, sorghum (Sorghum bicolor), and green foxtail (Setaria viridis), indicating the potential wide applications of this viral vector system for functional genomics studies in maize and other monocots. PMID:27208311

Avian influenza virus transmission to mammals.

Science.gov (United States)

Herfst, S; Imai, M; Kawaoka, Y; Fouchier, R A M

2014-01-01

Influenza A viruses cause yearly epidemics and occasional pandemics. In addition, zoonotic influenza A viruses sporadically infect humans and may cause severe respiratory disease and fatalities. Fortunately, most of these viruses do not have the ability to be efficiently spread among humans via aerosols or respiratory droplets (airborne transmission) and to subsequently cause a pandemic. However, adaptation of these zoonotic viruses to humans by mutation or reassortment with human influenza A viruses may result in airborne transmissible viruses with pandemic potential. Although our knowledge of factors that affect mammalian adaptation and transmissibility of influenza viruses is still limited, we are beginning to understand some of the biological traits that drive airborne transmission of influenza viruses among mammals. Increased understanding of the determinants and mechanisms of airborne transmission may aid in assessing the risks posed by avian influenza viruses to human health, and preparedness for such risks. This chapter summarizes recent discoveries on the genetic and phenotypic traits required for avian influenza viruses to become airborne transmissible between mammals.

Maedi in slaughtered sheep: a pathology and polymerase chain reaction study in southwestern Iran.

Science.gov (United States)

Azizi, Shahrzad; Tajbakhsh, Elahe; Fathi, Farzad; Oryan, Ahmad; Momtaz, Hassan; Goodarzi, Mehdi

2012-01-01

Maedi-visna (MV) is an important slow viral disease of sheep leading to a progressive lymphoproliferative disease. It affects multiple organs primarily the lungs, where it causes interstitial pneumonia (maedi). In this study, the lungs of 1,000 sheep carcasses were grossly inspected and those suspected to have maedi were studied at histopathological and molecular levels. A polymerase chain reaction (PCR) technique that amplified a 291-base pair DNA in the long terminal repeat (LTR) sequence of MV provirus was conducted on all the 50 suspected lungs together with 10 normal appearing lungs as controls. Amplicons of the expected size were detected in 11 (n=11/50) suspected sheep, and one of the 10 control sheep. Histopathologic study of the pulmonary lesions of all 11 (n=11/11) positive sheep showed MV lesions, including hyperplasia of the perivascular and peribronchiolar lymphoid cells, interstitial lymphoplasmacytic infiltration and smooth muscle hyperplasia and the histopathologic findings were correlated with PCR results. In contrast, the tissue sections of control animals were almost normal at histopathological level; however, PCR technique demonstrated that one of them was affected by maedi. This study showed that the LTR-PCR had high specificity and sensitivity in diagnosis of this viral infection. This study is the first to evaluate the prevalence of MV virus infection in sheep in Iran.

Zika virus disease

Science.gov (United States)

... May 2015, the virus was discovered for the first time in Brazil. It has now spread to many territories, states, and countries in: Caribbean Islands Central America Mexico South America Pacific Islands Africa The virus ...

A recombinant canine distemper virus expressing a modified rabies virus glycoprotein induces immune responses in mice.

Science.gov (United States)

Li, Zhili; Wang, Jigui; Yuan, Daoli; Wang, Shuang; Sun, Jiazeng; Yi, Bao; Hou, Qiang; Mao, Yaping; Liu, Weiquan

2015-06-01

Canine distemper virus (CDV) and rabies virus (RV) are two important pathogens of the dog. CDV, a member of the morbillivirus genus, has shown promise as an expression vector. The glycoprotein from RV is a main contributor to protective immunity and capable of eliciting the production of virus-neutralizing antibodies. In this study, we recovered an attenuated strain of canine distemper virus and constructed a recombinant virus, rCDV-RV-G, expressing a modified (R333Q) rabies virus glycoprotein (RV-G) of RV Flury strain LEP. RV-G expression by the recombinant viruses was confirmed. Furthermore, G was proved to be incorporated into the surface of CDV particles. While replication of the recombinant virus was slightly reduced compared with the parental CDV, it stably expressed the RV-G over ten serial passages. Inoculation of mice induced specific neutralizing antibodies against both RV-G and CDV. Therefore, the rCDV-RV-G has the potential as a vaccine that may be used to control rabies virus infection in dogs and other animals.

Identification and characterization of a virus-specific continuous B-cell epitope on the PrM/M protein of Japanese Encephalitis Virus: potential application in the detection of antibodies to distinguish Japanese Encephalitis Virus infection from West Nile Virus and Dengue Virus infections

OpenAIRE

Hua, Rong-Hong; Chen, Na-Sha; Qin, Cheng-Feng; Deng, Yong-Qiang; Ge, Jin-Ying; Wang, Xi-Jun; Qiao, Zu-Jian; Chen, Wei-Ye; Wen, Zhi-Yuan; Liu, Wen-Xin; Hu, Sen; Bu, Zhi-Gao

2010-01-01

Abstract Background Differential diagnose of Japanese encephalitis virus (JEV) infection from other flavivirus especially West Nile virus (WNV) and Dengue virus (DV) infection was greatly hindered for the serological cross-reactive. Virus specific epitopes could benefit for developing JEV specific antibodies detection methods. To identify the JEV specific epitopes, we fully mapped and characterized the continuous B-cell epitope of the PrM/M protein of JEV. Results To map the epitopes on the P...

Expression of varicella-zoster virus and herpes simplex virus in normal human trigeminal ganglia

International Nuclear Information System (INIS)

Vafai, A.; Wellish, M.; Devlin, M.; Gilden, D.H.; Murray, R.S.

1988-01-01

Lysates of radiolabeled explants from four human trigeminal ganglia were immunoprecipitated with antibodies to varicella-zoster virus (VZV) and to herpes simplex virus. Both herpes simplex virus- and VZV-specific proteins were detected in lysates of all four ganglia. Absence of reactivity in ganglion explants with monoclonal antibodies suggested that herpes simplex virus and VZV were not reactivated during the culture period. In situ hybridization studies demonstrated the presence of RNA transcripts from the VZV immediate early gene 63. This approach to the detection of herpes simplex virus and VZV expression in human ganglia should facilitate analysis of viral RNA and proteins in human sensory ganglia

Thermoactivation of viruses by microwaves

Energy Technology Data Exchange (ETDEWEB)

Mahnel, H.; von Brodorotti, H.S.

1981-01-01

Eight different viruses, suspended in drinking water, were examined for their ability to be inactivated by microwaves from a microwave oven. Up to a virus content of 10/sup 5/ TCID/sub 50//ml inactivation was successful within a few minutes of microwave treatment and occurred in parallel to the heat stability of the viruses. Evidence for direct effects of microwaves on viruses could not be detected. 7 of the viruses studied were inactivated rapidly when temperatures of 50 to 65/sup 0/C under microwave treatment were reached in the flowing water, while a bovine parvovirus was only inactivated by temperatures above 90/sup 0/C. The advantages of a thermal virus-decontamination of fluids and material by microwaves are discussed.

Autophagic machinery activated by dengue virus enhances virus replication

International Nuclear Information System (INIS)

Lee, Y.-R.; Lei, H.-Y.; Liu, M.-T.; Wang, J.-R.; Chen, S.-H.; Jiang-Shieh, Y.-F.; Lin, Y.-S.; Yeh, T.-M.; Liu, C.-C.; Liu, H.-S.

2008-01-01

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

Animal Models of Zika Virus

Science.gov (United States)

Bradley, Michael P; Nagamine, Claude M

2017-01-01

Zika virus has garnered great attention over the last several years, as outbreaks of the disease have emerged throughout the Western Hemisphere. Until quite recently Zika virus was considered a fairly benign virus, with limited clinical severity in both people and animals. The size and scope of the outbreak in the Western Hemisphere has allowed for the identification of severe clinical disease that is associated with Zika virus infection, most notably microcephaly among newborns, and an association with Guillian–Barré syndrome in adults. This recent association with severe clinical disease, of which further analysis strongly suggested causation by Zika virus, has resulted in a massive increase in the amount of both basic and applied research of this virus. Both small and large animal models are being used to uncover the pathogenesis of this emerging disease and to develop vaccine and therapeutic strategies. Here we review the animal-model–based Zika virus research that has been performed to date. PMID:28662753

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

Science.gov (United States)

2013-05-21

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration [Docket No. FDA-2013-N-0473] Human Immunodeficiency Virus Patient-Focused Drug Development and Human Immunodeficiency Virus Cure... an opportunity for public comment on human immunodeficiency virus (HIV) Patient-Focused Drug...

Natural history and treatment of hepatitis B virus and hepatitis C virus coinfection

Directory of Open Access Journals (Sweden)

Keeffe Emmet B

2005-09-01

Full Text Available Abstract Hepatitis B virus (HBV and hepatitis C virus (HCV coinfection is not uncommon as a result of similar routes of infection. Patients who are coinfected represent a unique group with diverse serologic profiles. Combined chronic hepatitis B and C leads to more severe liver disease and an increased risk of hepatocellular carcinoma. Furthermore, coinfected patients represent a treatment challenge. No standard recommendations exist for treatment of viral hepatitis due to dual HBV/HCV infection, and therefore treatment must be individualized based on patient variables such as serologic and virologic profiles, patient's prior exposure to antiviral treatment, and the presence of other parenterally transmitted viruses such as hepatitis D virus and human immunodeficiency virus. The natural history and treatment of patients with HBV and HCV coinfection is reviewed.

Codon usage bias and the evolution of influenza A viruses. Codon Usage Biases of Influenza Virus

Directory of Open Access Journals (Sweden)

Wong Emily HM

2010-08-01

Full Text Available Abstract Background The influenza A virus is an important infectious cause of morbidity and mortality in humans and was responsible for 3 pandemics in the 20th century. As the replication of the influenza virus is based on its host's machinery, codon usage of its viral genes might be subject to host selection pressures, especially after interspecies transmission. A better understanding of viral evolution and host adaptive responses might help control this disease. Results Relative Synonymous Codon Usage (RSCU values of the genes from segment 1 to segment 6 of avian and human influenza viruses, including pandemic H1N1, were studied via Correspondence Analysis (CA. The codon usage patterns of seasonal human influenza viruses were distinct among their subtypes and different from those of avian viruses. Newly isolated viruses could be added to the CA results, creating a tool to investigate the host origin and evolution of viral genes. It was found that the 1918 pandemic H1N1 virus contained genes with mammalian-like viral codon usage patterns, indicating that the introduction of this virus to humans was not through in toto transfer of an avian influenza virus. Many human viral genes had directional changes in codon usage over time of viral isolation, indicating the effect of host selection pressures. These changes reduced the overall GC content and the usage of G at the third codon position in the viral genome. Limited evidence of translational selection pressure was found in a few viral genes. Conclusions Codon usage patterns from CA allowed identification of host origin and evolutionary trends in influenza viruses, providing an alternative method and a tool to understand the evolution of influenza viruses. Human influenza viruses are subject to selection pressure on codon usage which might assist in understanding the characteristics of newly emerging viruses.

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

Science.gov (United States)

2013-08-02

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration [Docket No. FDA-2013-N-0473] Human Immunodeficiency Virus Patient-Focused Drug Development and Human Immunodeficiency Virus Cure... for the notice of public meeting entitled ``Human Immunodeficiency Virus (HIV) Patient-Focused Drug...

Chimeric human parainfluenza virus bearing the Ebola virus glycoprotein as the sole surface protein is immunogenic and highly protective against Ebola virus challenge

International Nuclear Information System (INIS)

Bukreyev, Alexander; Marzi, Andrea; Feldmann, Friederike; Zhang Liqun; Yang Lijuan; Ward, Jerrold M.; Dorward, David W.; Pickles, Raymond J.; Murphy, Brian R.; Feldmann, Heinz; Collins, Peter L.

2009-01-01

We generated a new live-attenuated vaccine against Ebola virus (EBOV) based on a chimeric virus HPIV3/ΔF-HN/EboGP that contains the EBOV glycoprotein (GP) as the sole transmembrane envelope protein combined with the internal proteins of human parainfluenza virus type 3 (HPIV3). Electron microscopy analysis of the virus particles showed that they have an envelope and surface spikes resembling those of EBOV and a particle size and shape resembling those of HPIV3. When HPIV3/ΔF-HN/EboGP was inoculated via apical surface of an in vitro model of human ciliated airway epithelium, the virus was released from the apical surface; when applied to basolateral surface, the virus infected basolateral cells but did not spread through the tissue. Following intranasal (IN) inoculation of guinea pigs, scattered infected cells were detected in the lungs by immunohistochemistry, but infectious HPIV3/ΔF-HN/EboGP could not be recovered from the lungs, blood, or other tissues. Despite the attenuation, the virus was highly immunogenic, and a single IN dose completely protected the animals against a highly lethal intraperitoneal challenge of guinea pig-adapted EBOV

VIRUS instrument enclosures

Science.gov (United States)

Prochaska, T.; Allen, R.; Mondrik, N.; Rheault, J. P.; Sauseda, M.; Boster, E.; James, M.; Rodriguez-Patino, M.; Torres, G.; Ham, J.; Cook, E.; Baker, D.; DePoy, Darren L.; Marshall, Jennifer L.; Hill, G. J.; Perry, D.; Savage, R. D.; Good, J. M.; Vattiat, Brian L.

2014-08-01

The Visible Integral-Field Replicable Unit Spectrograph (VIRUS) instrument will be installed at the Hobby-Eberly Telescope† in the near future. The instrument will be housed in two enclosures that are mounted adjacent to the telescope, via the VIRUS Support Structure (VSS). We have designed the enclosures to support and protect the instrument, to enable servicing of the instrument, and to cool the instrument appropriately while not adversely affecting the dome environment. The system uses simple HVAC air handling techniques in conjunction with thermoelectric and standard glycol heat exchangers to provide efficient heat removal. The enclosures also provide power and data transfer to and from each VIRUS unit, liquid nitrogen cooling to the detectors, and environmental monitoring of the instrument and dome environments. In this paper, we describe the design and fabrication of the VIRUS enclosures and their subsystems.

Hepatitis A virus antibody

International Nuclear Information System (INIS)

Novak, J.; Kselikova, M.; Urbankova, J.

1980-01-01

A description is presented of a radioimmunoassay designed to prove the presence of the antibody against the hepatitis A virus (HA Ab, anti-Ha) using an Abbott HAVAB set. This proof as well as the proof of the antibody against the nucleus of the hepatitis B virus is based on competition between a normal antibody against hepatitis A virus and a 125 I-labelled antibody for the binding sites of a specific antigen spread all over the surface of a tiny ball; this is then indirect proof of the antibody under investigation. The method is described of reading the results from the number of impulses per 60 seconds: the higher the titre of the antibody against the hepatitis A virus in the serum examined, the lower the activity of the specimen concerned. The rate is reported of incidence of the antibody against the hepatitis A virus in a total of 68 convalescents after hepatitis A; the antibody was found in 94.1%. The immunoglobulin made from the convalescents' plasma showed the presence of antibodies in dilutions as high as 1:250 000 while the comparable ratio for normal immunoglobulin Norga was only 1:2500. Differences are discussed in the time incidence of the antibodies against the hepatitis A virus, the antibodies against the surface antigen of hepatitis B, and the antibody against the nucleus of the hepatitis V virus. (author)

Avian influenza A virus and Newcastle disease virus mono- and co-infections in birds

Directory of Open Access Journals (Sweden)

Iv. Zarkov

2017-06-01

Full Text Available The main features of avian influenza viruses (AIV and Newcastle disease virus (APMV-1, the possibilities for isolation and identification in laboratory conditions, methods of diagnostics, main hosts, clinical signs and virus shedding are reviewed in chronological order. The other part of the review explains the mechanisms and interactions in cases of co-infection of AIV and APMV-1, either between them or with other pathogens in various indicator systems – cell cultures, chick embryos or birds. The emphasis is placed on quantitative data on the virus present mainly in the first ten days following experimental infection of birds, the periods of virus carrier ship and shedding, clinical signs, pathological changes, diagnostic challenges

BS-virus-finder

DEFF Research Database (Denmark)

Gao, Shengjie; Hu, Xuesong; Xu, Fengping

2018-01-01

Background: DNA methylation plays a key role in the regulation of gene expression and carcinogenesis. Bisulfite sequencing studies mainly focus on calling SNP, DMR, and ASM. Until now, only a few software tools focus on virus integration using bisulfite sequencing data. Findings: We have developed...... a new and easy-to-use software tool, named BS-virus-finder (BSVF, RRID:SCR_015727), to detect viral integration breakpoints in whole human genomes. The tool is hosted at https://github.com/BGI-SZ/BSVF. Conclusions: BS-virus-finder demonstrates high sensitivity and specificity. It is useful in epigenetic...

Ebola (Ebola Virus Disease): Diagnosis

Science.gov (United States)

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Ebola (Ebola Virus Disease): Transmission

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Ebola (Ebola Virus Disease): Treatment

Science.gov (United States)

... Search Form Controls Cancel Submit Search the CDC Ebola (Ebola Virus Disease) Note: Javascript is disabled or is ... message, please visit this page: About CDC.gov . Ebola (Ebola Virus Disease) What is Ebola Virus Disease? ...

Tomato ringspot virus and Tobacco ringspot virus in Highbush Blueberry in New York State

Science.gov (United States)

A survey of highbush blueberry (Vaccinium corymbosum L.) cultivars Patriot and Bluecrop showing virus-like symptoms and decline in vigor in New York was conducted to assess the occurrence of viruses. Leaf samples from symptomatic and asymptomatic bushes reacted positively to Tobacco ringspot virus ...

Protecting Anti-virus Programs From Viral Attacks

OpenAIRE

Mishra, Umakant

2013-01-01

During a fight between viruses and anti-viruses it is not always predictable that the anti-virus is going to win. There are many malicious viruses which target to attack and paralyze the anti-viruses. It is necessary for an anti-virus to detect and destroy the malware before its own files are detected and destroyed by the malware. The anti-virus may follow thorough testing and auditing procedures to fix all its bugs before releasing the software in the market. Besides the anti-virus may use a...

Remarkable morphological diversity of viruses and virus-like particles in hot terrestrial environments.

Science.gov (United States)

Rachel, R; Bettstetter, M; Hedlund, B P; Häring, M; Kessler, A; Stetter, K O; Prangishvili, D

2002-12-01

Electron microscopic studies of the viruses in two hot springs (85 degrees C, pH 1.5-2.0, and 75-93 degrees C, pH 6.5) in Yellowstone National Park revealed particles with twelve different morphotypes. This diversity encompassed known viruses of hyperthermophilic archaea, filamentous Lipothrixviridae, rod-shaped Rudiviridae, and spindle-shaped Fuselloviridae, and novel morphotypes previously not observed in nature. Two virus types resembled head-and-tail bacteriophages from the families Siphoviridae and Podoviridae, and constituted the first observation of these viruses in a hydrothermal environment. Viral hosts in the acidic spring were members of the hyperthermophilic archaeal genus Acidianus.

General properties of grapevine viruses occurring in Hungary

OpenAIRE

Eszter Cseh; András Takács; László Kocsis; Richard Gáborjányi

2012-01-01

The past fifty years important advances have been made in the field of grapevine virus research, including characterization of pathogens and control measurements. Still the occurrence of Grapevine fanleaf virus (GFLV), Arabis mosaic virus (ArMV), Tomato black ring virus (TBRV), Grapevine chrome mosaic virus (GCMV), Alfalfa mosaic virus (AMV), Grapevine Bulgarian latent virus (GBLV), Grapevine fleck virus (GFkV), Grapevine leafroll- associated viruses (GLRaV1-4), Grapevine virus A (GVA), Grape...

Residues R199H200 of prototype foamy virus transactivator Bel1 contribute to its binding with LTR and IP promoters but not its nuclear localization

International Nuclear Information System (INIS)

Ma, Qinglin; Tan, Juan; Cui, Xiaoxu; Luo, Di; Yu, Miao; Liang, Chen; Qiao, Wentao

2014-01-01

Prototype foamy virus encodes a transactivator called Bel1 that enhances viral gene transcription and is essential for PFV replication. Nuclear localization of Bel1 has been reported to rely on two proximal basic motifs R 199 H 200 and R 221 R 222 R 223 that likely function together as a bipartite nuclear localization signal. In this study, we report that mutating R 221 R 222 R 223 , but not R 199 H 200 , relocates Bel1 from the nucleus to the cytoplasm, suggesting an essential role for R 221 R 222 R 223 in the nuclear localization of Bel1. Although not affecting the nuclear localization of Bel1, mutating R 199 H 200 disables Bel1 from transactivating PFV promoters. Results of EMSA reveal that the R 199 H 200 residues are vital for the binding of Bel1 to viral promoter DNA. Moreover, mutating R 199 H 200 in Bel1 impairs PFV replication to a much greater extent than mutating R 221 R 222 R 223 . Collectively, our findings suggest that R 199 H 200 directly participate in Bel1 binding to viral promoter DNA and are indispensible for Bel1 transactivation activity. - Highlights: • The R 221 R 222 R 223 residues are essential for the nuclear localization of Bel1. • Although not affecting the nuclear localization of Bel1, mutating R 199 H 200 disables Bel1 from transactivating PFV promoters. • The R 199 H 200 residues directly participate in Bel1 binding to viral promoter DNA. • Mutating R 199 H 200 in Bel1 impairs PFV replication to a much greater extent than mutating R 221 R 222 R 223

General properties of grapevine viruses occurring in Hungary

Directory of Open Access Journals (Sweden)

Eszter Cseh

2012-03-01

Full Text Available The past fifty years important advances have been made in the field of grapevine virus research, including characterization of pathogens and control measurements. Still the occurrence of Grapevine fanleaf virus (GFLV, Arabis mosaic virus (ArMV, Tomato black ring virus (TBRV, Grapevine chrome mosaic virus (GCMV, Alfalfa mosaic virus (AMV, Grapevine Bulgarian latent virus (GBLV, Grapevine fleck virus (GFkV, Grapevine leafroll- associated viruses (GLRaV1-4, Grapevine virus A (GVA, Grapevine virus B (GVB and Grapevine rupestris stem pitting- associated virus (GRSPaV have been reported in Hungary and characterized by conventional methods as woody indexing, herbaceous indexing and serological methods. Among grapevine viruses the Grapevine line pattern virus (GLPV seems to be uncial; because it was reported only in Hungary. Causal agents of several grapevine diseases, like enation, vein necrosis and vein mosaic remained undiscovered. These virus-like diseases occurred only sporadically, without economic importance.

Control of sweet potato virus diseases.

Science.gov (United States)

Loebenstein, Gad

2015-01-01

Sweet potato (Ipomoea batatas) is ranked seventh in global food crop production and is the third most important root crop after potato and cassava. Sweet potatoes are vegetative propagated from vines, root slips (sprouts), or tubers. Therefore, virus diseases can be a major constrain, reducing yields markedly, often more than 50%. The main viruses worldwide are Sweet potato feathery mottle virus (SPFMV) and Sweet potato chlorotic stunt virus (SPCSV). Effects on yields by SPFMV or SPCSV alone are minor, or but in complex infection by the two or other viruses yield losses of 50%. The orthodox way of controlling viruses in vegetative propagated crops is by supplying the growers with virus-tested planting material. High-yielding plants are tested for freedom of viruses by PCR, serology, and grafting to sweet potato virus indicator plants. After this, meristem tips are taken from those plants that reacted negative. The meristems were grown into plants which were kept under insect-proof conditions and away from other sweet potato material for distribution to farmers after another cycle of reproduction. © 2015 Elsevier Inc. All rights reserved.

Autophagy in Measles Virus Infection

Directory of Open Access Journals (Sweden)

Aurore Rozières

2017-11-01

Full Text Available Autophagy is a biological process that helps cells to recycle obsolete cellular components and which greatly contributes to maintaining cellular integrity in response to environmental stress factors. Autophagy is also among the first lines of cellular defense against invading microorganisms, including viruses. The autophagic destruction of invading pathogens, a process referred to as xenophagy, involves cytosolic autophagy receptors, such as p62/SQSTM1 (Sequestosome 1 or NDP52/CALCOCO2 (Nuclear Dot 52 KDa Protein/Calcium Binding And Coiled-Coil Domain 2, which bind to microbial components and target them towards growing autophagosomes for degradation. However, most, if not all, infectious viruses have evolved molecular tricks to escape from xenophagy. Many viruses even use autophagy, part of the autophagy pathway or some autophagy-associated proteins, to improve their infectious potential. In this regard, the measles virus, responsible for epidemic measles, has a unique interface with autophagy as the virus can induce multiple rounds of autophagy in the course of infection. These successive waves of autophagy result from distinct molecular pathways and seem associated with anti- and/or pro-measles virus consequences. In this review, we describe what the autophagy–measles virus interplay has taught us about both the biology of the virus and the mechanistic orchestration of autophagy.

Strategy as a Virus

DEFF Research Database (Denmark)

Obed Madsen, Søren

This article is based on virus theory (Røvik, 2007, 2011), and proposes to develop a framework that defines technology as a virus that penetrates the organism of an organization. The framework develops a new vocabulary, which can help in analyzing technologies and their negative effects on actors...... and organizations. In this paper, the virus theory is used to analyze a strategy process in an organization as an example of a technology. It shows how the strategy over time creates a memory loss, where the managers who are exposed to the virus forget their critique of the new strategy concept. The article also...... shows how resistant can be understood as being immune to a virus, since the strategy concepts bears resemblance to a former strategy concept. The article also argues that there should be more focus on the negative impacts of management tool and especially how organizations and managers are dealing...

Plant virus sensitivity to gamma irradiation

International Nuclear Information System (INIS)

Gyoergyne Czeck, B.

1979-01-01

Preliminary experiments for prevention were conducted with weakened plant viruses, namely with Arabis mosaic virus isolated from strawberries and tobacco mosaic virus. Treatment 24 hours prior to the infection with the radiation-weakened virus resulted in a 60-70% infection prevention. (author)

Unprecedented genomic diversity of RNA viruses in arthropods reveals the ancestry of negative-sense RNA viruses.

Science.gov (United States)

Li, Ci-Xiu; Shi, Mang; Tian, Jun-Hua; Lin, Xian-Dan; Kang, Yan-Jun; Chen, Liang-Jun; Qin, Xin-Cheng; Xu, Jianguo; Holmes, Edward C; Zhang, Yong-Zhen

2015-01-29

Although arthropods are important viral vectors, the biodiversity of arthropod viruses, as well as the role that arthropods have played in viral origins and evolution, is unclear. Through RNA sequencing of 70 arthropod species we discovered 112 novel viruses that appear to be ancestral to much of the documented genetic diversity of negative-sense RNA viruses, a number of which are also present as endogenous genomic copies. With this greatly enriched diversity we revealed that arthropods contain viruses that fall basal to major virus groups, including the vertebrate-specific arenaviruses, filoviruses, hantaviruses, influenza viruses, lyssaviruses, and paramyxoviruses. We similarly documented a remarkable diversity of genome structures in arthropod viruses, including a putative circular form, that sheds new light on the evolution of genome organization. Hence, arthropods are a major reservoir of viral genetic diversity and have likely been central to viral evolution.

Protection against myxomatosis and rabbit viral hemorrhagic disease with recombinant myxoma viruses expressing rabbit hemorrhagic disease virus capsid protein.

Science.gov (United States)

Bertagnoli, S; Gelfi, J; Le Gall, G; Boilletot, E; Vautherot, J F; Rasschaert, D; Laurent, S; Petit, F; Boucraut-Baralon, C; Milon, A

1996-08-01

Two myxoma virus-rabbit hemorrhagic disease virus (RHDV) recombinant viruses were constructed with the SG33 strain of myxoma virus to protect rabbits against myxomatosis and rabbit viral hemorrhagic disease. These recombinant viruses expressed the RHDV capsid protein (VP60). The recombinant protein, which is 60 kDa in size, was antigenic, as revealed by its reaction in immunoprecipitation with antibodies raised against RHDV. Both recombinant viruses induced high levels of RHDV- and myxoma virus-specific antibodies in rabbits after immunization. Inoculations by the intradermal route protected animals against virulent RHDV and myxoma virus challenges.

A Literature Review of Zika Virus.

Science.gov (United States)

Plourde, Anna R; Bloch, Evan M

2016-07-01

Zika virus is a mosquitoborne flavivirus that is the focus of an ongoing pandemic and public health emergency. Previously limited to sporadic cases in Africa and Asia, the emergence of Zika virus in Brazil in 2015 heralded rapid spread throughout the Americas. Although most Zika virus infections are characterized by subclinical or mild influenza-like illness, severe manifestations have been described, including Guillain-Barre syndrome in adults and microcephaly in babies born to infected mothers. Neither an effective treatment nor a vaccine is available for Zika virus; therefore, the public health response primarily focuses on preventing infection, particularly in pregnant women. Despite growing knowledge about this virus, questions remain regarding the virus's vectors and reservoirs, pathogenesis, genetic diversity, and potential synergistic effects of co-infection with other circulating viruses. These questions highlight the need for research to optimize surveillance, patient management, and public health intervention in the current Zika virus epidemic.

Long Terminal Repeat Retrotransposon Content in Eight Diploid Sunflower Species Inferred from Next-Generation Sequence Data

Science.gov (United States)

Tetreault, Hannah M.; Ungerer, Mark C.

2016-01-01

The most abundant transposable elements (TEs) in plant genomes are Class I long terminal repeat (LTR) retrotransposons represented by superfamilies gypsy and copia. Amplification of these superfamilies directly impacts genome structure and contributes to differential patterns of genome size evolution among plant lineages. Utilizing short-read Illumina data and sequence information from a panel of Helianthus annuus (sunflower) full-length gypsy and copia elements, we explore the contribution of these sequences to genome size variation among eight diploid Helianthus species and an outgroup taxon, Phoebanthus tenuifolius. We also explore transcriptional dynamics of these elements in both leaf and bud tissue via RT-PCR. We demonstrate that most LTR retrotransposon sublineages (i.e., families) display patterns of similar genomic abundance across species. A small number of LTR retrotransposon sublineages exhibit lineage-specific amplification, particularly in the genomes of species with larger estimated nuclear DNA content. RT-PCR assays reveal that some LTR retrotransposon sublineages are transcriptionally active across all species and tissue types, whereas others display species-specific and tissue-specific expression. The species with the largest estimated genome size, H. agrestis, has experienced amplification of LTR retrotransposon sublineages, some of which have proliferated independently in other lineages in the Helianthus phylogeny. PMID:27233667

Tobacco ringspot virus

Science.gov (United States)

Tobacco ringspot virus (TRSV), and its vector, the dagger nematodes (Xiphinema americanum and related species) are widely distributed throughout the world. Cucumber, melon, and watermelon are particularly affected by TRSV. Symptoms can vary with plant age, the strain of the virus, and environment...

Viruses affecting lentil (Lens culinaris Medik. in Greece; incidence and genetic variability of Bean leafroll virus and Pea enation mosaic virus

Directory of Open Access Journals (Sweden)

Elisavet K. CHATZIVASSILIOU

2016-07-01

Full Text Available In Greece, lentil (Lens culinaris Medik. crops are mainly established with non-certified seeds of local landraces, implying high risks for seed transmitted diseases. During April and May of the 2007–2012 growing seasons, surveys were conducted in eight regions of Greece (Attiki, Evros, Fthiotida, Korinthos, Kozani, Larissa, Lefkada and Viotia to monitor virus incidence in lentil fields. A total of 1216 lentil samples, from plants exhibiting symptoms suggestive of virus infection, were analyzed from 2007 to 2009, using tissue-blot immunoassays (TBIA. Pea seed-borne mosaic virus (PSbMV overall incidence was 4.9%, followed by Alfalfa mosaic virus (AMV (2.4% and Bean yellow mosaic virus (BYMV (1.0%. When 274 of the samples were tested for the presence of luteoviruses, 38.8% were infected with Bean leafroll virus (BLRV. Since BLRV was not identified in the majority of the samples collected from 2007 to 2009, representative symptomatic plants (360 samples were collected in further surveys performed from 2010 to 2012 and tested by ELISA. Two viruses prevailed in those samples: BLRV (36.1% was associated with stunting, yellowing, and reddening symptoms and Pea enation mosaic virus-1 (PEMV-1 (35.0% was associated with mosaic and mottling symptoms. PSbMV (2.2%, AMV (2.2%, BYMV (3.9% and CMV (2.8% were also detected. When the molecular variability was analyzed for representative isolates, collected from the main Greek lentil production areas, five BLRV isolates showed 95% identity for the coat protein (CP gene and 99% for the 3’ end region. Three Greek PEMV isolates co-clustered with an isolate from Germany when their CP sequence was compared with isolates with no mutation in the aphid transmission gene. Overall, limited genetic variability was detected among Greek isolates of BLRV and PEMV.

Virus-neutralizing antibody response of mice to consecutive infection with human and avian influenza A viruses.

Science.gov (United States)

Janulíková, J; Stropkovská, A; Bobišová, Z; Košík, I; Mucha, V; Kostolanský, F; Varečková, E

2015-06-01

In this work we simulated in a mouse model a naturally occurring situation of humans, who overcame an infection with epidemic strains of influenza A, and were subsequently exposed to avian influenza A viruses (IAV). The antibody response to avian IAV in mice previously infected with human IAV was analyzed. We used two avian IAV (A/Duck/Czechoslovakia/1956 (H4N6) and the attenuated virus rA/Viet Nam/1203-2004 (H5N1)) as well as two human IAV isolates (virus A/Mississippi/1/1985 (H3N2) of medium virulence and A/Puerto Rico/8/1934 (H1N1) of high virulence). Two repeated doses of IAV of H4 or of H5 virus elicited virus-specific neutralizing antibodies in mice. Exposure of animals previously infected with human IAV (of H3 or H1 subtype) to IAV of H4 subtype led to the production of antibodies neutralizing H4 virus in a level comparable with the level of antibodies against the human IAV used for primary infection. In contrast, no measurable levels of virus-neutralizing (VN) antibodies specific to H5 virus were detected in mice infected with H5 virus following a previous infection with human IAV. In both cases the secondary infection with avian IAV led to a significant increase of the titer of VN antibodies specific to the corresponding human virus used for primary infection. Moreover, cross-reactive HA2-specific antibodies were also induced by sequential infection. By virtue of these results we suggest that the differences in the ability of avian IAV to induce specific antibodies inhibiting virus replication after previous infection of mice with human viruses can have an impact on the interspecies transmission and spread of avian IAV in the human population.

Differential diagnosis of feline leukemia virus subgroups using pseudotype viruses expressing green fluorescent protein.

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Nakamura, Megumi; Sato, Eiji; Miura, Tomoyuki; Baba, Kenji; Shimoda, Tetsuya; Miyazawa, Takayuki

2010-06-01

Feline leukemia virus (FeLV) is classified into three receptor interference subgroups, A, B and C. In this study, to differentiate FeLV subgroups, we developed a simple assay system using pseudotype viruses expressing green fluorescent protein (GFP). We prepared gfp pseudotype viruses, named gfp(FeLV-A), gfp(FeLV-B) and gfp(FeLV-C) harboring envelopes of FeLV-A, B and C, respectively. The gfp pseudotype viruses completely interfered with the same subgroups of FeLV reference strains on FEA cells (a feline embryonic fibroblast cell line). We also confirmed that the pseudotype viruses could differentiate FeLV subgroups in field isolates. The assay will be useful for differential diagnosis of FeLV subgroups in veterinary diagnostic laboratories in the future.

Interventions Against West Nile Virus, Rift Valley Fever Virus, and Crimean-Congo Hemorrhagic Fever Virus: Where Are We?

NARCIS (Netherlands)

Kortekaas, J.A.; Ergonul, O.; Moormann, R.J.M.

2010-01-01

ARBO-ZOONET is an international network financed by the European Commission's seventh framework program. The major goal of this initiative is capacity building for the control of emerging viral vector-borne zoonotic diseases, with a clear focus on West Nile virus, Rift Valley fever virus, and

West Nile virus: North American experience

Science.gov (United States)

Hofmeister, Erik K.

2011-01-01

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.

Drosophila Nora virus capsid proteins differ from those of other picorna-like viruses.

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Ekström, Jens-Ola; Habayeb, Mazen S; Srivastava, Vaibhav; Kieselbach, Thomas; Wingsle, Gunnar; Hultmark, Dan

2011-09-01

The recently discovered Nora virus from Drosophila melanogaster is a single-stranded RNA virus. Its published genomic sequence encodes a typical picorna-like cassette of replicative enzymes, but no capsid proteins similar to those in other picorna-like viruses. We have now done additional sequencing at the termini of the viral genome, extending it by 455 nucleotides at the 5' end, but no more coding sequence was found. The completeness of the final 12,333-nucleotide sequence was verified by the production of infectious virus from the cloned genome. To identify the capsid proteins, we purified Nora virus particles and analyzed their proteins by mass spectrometry. Our results show that the capsid is built from three major proteins, VP4A, B and C, encoded in the fourth open reading frame of the viral genome. The viral particles also contain traces of a protein from the third open reading frame, VP3. VP4A and B are not closely related to other picorna-like virus capsid proteins in sequence, but may form similar jelly roll folds. VP4C differs from the others and is predicted to have an essentially α-helical conformation. In a related virus, identified from EST database sequences from Nasonia parasitoid wasps, VP4C is encoded in a separate open reading frame, separated from VP4A and B by a frame-shift. This opens a possibility that VP4C is produced in non-equimolar quantities. Altogether, our results suggest that the Nora virus capsid has a different protein organization compared to the order Picornavirales. Copyright © 2011 Elsevier B.V. All rights reserved.

Global Mapping of O-Glycosylation of Varicella Zoster Virus, Human Cytomegalovirus, and Epstein-Barr Virus*

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Bagdonaite, Ieva; Nordén, Rickard; Joshi, Hiren J.; King, Sarah L.; Vakhrushev, Sergey Y.; Olofsson, Sigvard; Wandall, Hans H.

2016-01-01

Herpesviruses are among the most complex and widespread viruses, infection and propagation of which depend on envelope proteins. These proteins serve as mediators of cell entry as well as modulators of the immune response and are attractive vaccine targets. Although envelope proteins are known to carry glycans, little is known about the distribution, nature, and functions of these modifications. This is particularly true for O-glycans; thus we have recently developed a “bottom up” mass spectrometry-based technique for mapping O-glycosylation sites on herpes simplex virus type 1. We found wide distribution of O-glycans on herpes simplex virus type 1 glycoproteins and demonstrated that elongated O-glycans were essential for the propagation of the virus. Here, we applied our proteome-wide discovery platform for mapping O-glycosites on representative and clinically significant members of the herpesvirus family: varicella zoster virus, human cytomegalovirus, and Epstein-Barr virus. We identified a large number of O-glycosites distributed on most envelope proteins in all viruses and further demonstrated conserved patterns of O-glycans on distinct homologous proteins. Because glycosylation is highly dependent on the host cell, we tested varicella zoster virus-infected cell lysates and clinically isolated virus and found evidence of consistent O-glycosites. These results present a comprehensive view of herpesvirus O-glycosylation and point to the widespread occurrence of O-glycans in regions of envelope proteins important for virus entry, formation, and recognition by the host immune system. This knowledge enables dissection of specific functional roles of individual glycosites and, moreover, provides a framework for design of glycoprotein vaccines with representative glycosylation. PMID:27129252

Iguana Virus, a Herpes-Like Virus Isolated from Cultured Cells of a Lizard, Iguana iguana

Science.gov (United States)

Clark, H. Fred; Karzon, David T.

1972-01-01

An agent cytopathic for Terrapene and Iguana cell cultures was isolated from spontaneously degenerating cell cultures prepared from a green iguana (Iguana iguana). The agent, designated iguana virus, caused a cytopathic effect (CPE) of a giant cell type, with eosinophilic inclusions commonly observed within giant cell nuclei. Incubation temperature had a marked effect on CPE and on virus release from infected cells. Within the range of 23 to 36 C, low temperatures favored CPE characterized by cytolysis and small giant cell formation, and significant virus release was observed. At warmer temperatures, a purely syncytial type of CPE and total absence of released virus were noted. A unique type of hexagonal eosinophilic cytoplasmic inclusion was observed within syncytia of infected Terrapene cell cultures incubated at 36 C. In vivo studies revealed no evidence of pathogenicity of iguana virus for suckling mice, embryonated hen's eggs, or several species of reptiles and amphibians. Inoculation of iguana virus into young iguanas consistently caused infection that was “unmasked” only when cell cultures were prepared directly from the infected animal. Filtration studies revealed a virion size of >100 nm and Iguana virus is ether-sensitive and, as presumptively indicated by studies of inhibition by bromodeoxyuridine, possesses a deoxyribonucleic type of nucleic acid. The virus characteristics described, as well as electron microscopy observations described in a separate report, indicate that iguana virus is a member of the herpesvirus group. Images PMID:4344303

Characterization of Ebola virus entry by using pseudotyped viruses: identification of receptor-deficient cell lines.

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Wool-Lewis, R J; Bates, P

1998-04-01

Studies analyzing Ebola virus replication have been severely hampered by the extreme pathogenicity of this virus. To permit analysis of the host range and function of the Ebola virus glycoprotein (Ebo-GP), we have developed a system for pseudotyping these glycoproteins into murine leukemia virus (MLV). This pseudotyped virus, MLV(Ebola), can be readily concentrated to titers which exceed 5 x 10(6) infectious units/ml and is effectively neutralized by antibodies specific for Ebo-GP. Analysis of MLV(Ebola) infection revealed that the host range conferred by Ebo-GP is very broad, extending to cells of a variety of species. Notably, all lymphoid cell lines tested were completely resistant to infection; we speculate that this is due to the absence of a cellular receptor for Ebo-GP on B and T cells. The generation of high-titer MLV(Ebola) pseudotypes will be useful for the analysis of immune responses to Ebola virus infection, development of neutralizing antibodies, analysis of glycoprotein function, and isolation of the cellular receptor(s) for the Ebola virus.

Solanum americanum: reservoir for Potato virus Y and Cucumber mosaic virus in sweet pepper crops

Directory of Open Access Journals (Sweden)

Monika Fecury Moura

2014-03-01

Full Text Available Weeds can act as important reservoirs for viruses. Solanum americanum (Black nightshade is a common weed in Brazil and samples showing mosaic were collected from sweet pepper crops to verify the presence of viruses. One sample showed mixed infection between Cucumber mosaic virus (CMV and Potato virus Y (PVY and one sample showed simple infection by PVY. Both virus species were transmitted by plant extract and caused mosaic in tomato (Solanum lycopersicum cv. Santa Clara, sweet pepper (Capsicum annuum cv. Magda, Nicotiana benthamiana and N. tabaccum TNN, and local lesions on Chenopodium quinoa, C. murale and C. amaranticolor. The coat protein sequences for CMV and PVY found in S. americanum are phylogenetically more related to isolates from tomato. We conclude that S. americanum can act as a reservoir for different viruses during and between sweet pepper crop seasons.

Archaeal Viruses: Diversity, Replication, and Structure.

Science.gov (United States)

Dellas, Nikki; Snyder, Jamie C; Bolduc, Benjamin; Young, Mark J

2014-11-01

The Archaea-and their viruses-remain the most enigmatic of life's three domains. Once thought to inhabit only extreme environments, archaea are now known to inhabit diverse environments. Even though the first archaeal virus was described over 40 years ago, only 117 archaeal viruses have been discovered to date. Despite this small number, these viruses have painted a portrait of enormous morphological and genetic diversity. For example, research centered around the various steps of the archaeal virus life cycle has led to the discovery of unique mechanisms employed by archaeal viruses during replication, maturation, and virion release. In many instances, archaeal virus proteins display very low levels of sequence homology to other proteins listed in the public database, and therefore, structural characterization of these proteins has played an integral role in functional assignment. These structural studies have not only provided insights into structure-function relationships but have also identified links between viruses across all three domains of life.

Top 10 plant viruses in molecular plant pathology.

Science.gov (United States)

Scholthof, Karen-Beth G; Adkins, Scott; Czosnek, Henryk; Palukaitis, Peter; Jacquot, Emmanuel; Hohn, Thomas; Hohn, Barbara; Saunders, Keith; Candresse, Thierry; Ahlquist, Paul; Hemenway, Cynthia; Foster, Gary D

2011-12-01

Many scientists, if not all, feel that their particular plant virus should appear in any list of the most important plant viruses. However, to our knowledge, no such list exists. The aim of this review was to survey all plant virologists with an association with Molecular Plant Pathology and ask them to nominate which plant viruses they would place in a 'Top 10' based on scientific/economic importance. The survey generated more than 250 votes from the international community, and allowed the generation of a Top 10 plant virus list for Molecular Plant Pathology. The Top 10 list includes, in rank order, (1) Tobacco mosaic virus, (2) Tomato spotted wilt virus, (3) Tomato yellow leaf curl virus, (4) Cucumber mosaic virus, (5) Potato virus Y, (6) Cauliflower mosaic virus, (7) African cassava mosaic virus, (8) Plum pox virus, (9) Brome mosaic virus and (10) Potato virus X, with honourable mentions for viruses just missing out on the Top 10, including Citrus tristeza virus, Barley yellow dwarf virus, Potato leafroll virus and Tomato bushy stunt virus. This review article presents a short review on each virus of the Top 10 list and its importance, with the intent of initiating discussion and debate amongst the plant virology community, as well as laying down a benchmark, as it will be interesting to see in future years how perceptions change and which viruses enter and leave the Top 10. © 2011 The Authors. Molecular Plant Pathology © 2011 BSPP and Blackwell Publishing Ltd.

Computer Bytes, Viruses and Vaccines.

Science.gov (United States)

Palmore, Teddy B.

1989-01-01

Presents a history of computer viruses, explains various types of viruses and how they affect software or computer operating systems, and describes examples of specific viruses. Available vaccines are explained, and precautions for protecting programs and disks are given. (nine references) (LRW)

Selective host range restriction of goat cells for recombinant murine leukemia virus and feline leukemia virus type A.

OpenAIRE

Fischinger, P J; Thiel, H J; Blevins, C S; Dunlop, N M

1981-01-01

We isolated a strain of normal goat fibroblasts which was uniquely selective in that it allowed the replication of xenotropic murine leukemia virus but not polytropic recombinant murine leukemia virus. In addition, feline leukemia virus type A replication was severely diminished in these goat cells, whereas feline leukemia virus type B and feline endogenous RD114-CCC viruses replicated efficiently. No other known cells exhibit this pattern of virus growth restriction. These goat cells allow t...

Reassortant H1N1 influenza virus vaccines protect pigs against pandemic H1N1 influenza virus and H1N2 swine influenza virus challenge.

Science.gov (United States)

Yang, Huanliang; Chen, Yan; Shi, Jianzhong; Guo, Jing; Xin, Xiaoguang; Zhang, Jian; Wang, Dayan; Shu, Yuelong; Qiao, Chuanling; Chen, Hualan

2011-09-28

Influenza A (H1N1) virus has caused human influenza outbreaks in a worldwide pandemic since April 2009. Pigs have been found to be susceptible to this influenza virus under experimental and natural conditions, raising concern about their potential role in the pandemic spread of the virus. In this study, we generated a high-growth reassortant virus (SC/PR8) that contains the hemagglutinin (HA) and neuraminidase (NA) genes from a novel H1N1 isolate, A/Sichuan/1/2009 (SC/09), and six internal genes from A/Puerto Rico/8/34 (PR8) virus, by genetic reassortment. The immunogenicity and protective efficacy of this reassortant virus were evaluated at different doses in a challenge model using a homologous SC/09 or heterologous A/Swine/Guangdong/1/06(H1N2) virus (GD/06). Two doses of SC/PR8 virus vaccine elicited high-titer serum hemagglutination inhibiting (HI) antibodies specific for the 2009 H1N1 virus and conferred complete protection against challenge with either SC/09 or GD/06 virus, with reduced lung lesions and viral shedding in vaccine-inoculated animals compared with non-vaccinated control animals. These results indicated for the first time that a high-growth SC/PR8 reassortant H1N1 virus exhibits properties that are desirable to be a promising vaccine candidate for use in swine in the event of a pandemic H1N1 influenza. Copyright © 2011 Elsevier B.V. All rights reserved.

Recombinant Vaccinia Virus: Immunization against Multiple Pathogens

Science.gov (United States)

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

1985-09-01

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.

Zika Virus: An Emergent Neuropathological Agent

Science.gov (United States)

White, Martyn K.; Wollebo, Hassen S.; Beckham, J. David; Tyler, Kenneth L.; Khalili, Kamel

2016-01-01

The emergence of Zika virus in the Americas has followed a pattern that is familiar from earlier epidemics of other viruses, where a new disease is introduced into a human population and then spreads rapidly with important public health consequences. In the case of Zika virus, an accumulating body of recent evidence implicates the virus in the etiology of serious pathologies of the human nervous system, that is, the occurrence of microcephaly in neonates and Guillain–Barré syndrome in adults. Zika virus is an arbovirus (arthropod-borne virus) and a member of the family Flaviviridae, genus Flavivirus. Zika virions are enveloped and icosahedral, and contain a nonsegmented, single-stranded, positive-sense RNA genome, which encodes 3 structural and 7 nonstructural proteins that are expressed as a single polyprotein that undergoes cleavage. Zika genomic RNA replicates in the cytoplasm of infected host cells. Zika virus was first detected in 1947 in the blood of a febrile monkey in Uganda’s Zika Forest and in crushed suspensions of the Aedes mosquito, which is one of the vectors for Zika virus. The virus remained obscure, with a few human cases confined to Africa and Asia. There are two lineages of the Zika virus, African and Asian, with the Asian strain causing outbreaks in Micronesia in 2007 and French Polynesia in 2013–2014. From here, the virus spread to Brazil with the first report of autochthonous Zika transmission in the Americas in March 2015. The rapid advance of the virus in the Americas and its likely association with microcephaly and Guillain–Barré syndrome make Zika an urgent public health concern. PMID:27464346

Viral coinfection is shaped by host ecology and virus-virus interactions across diverse microbial taxa and environments.

Science.gov (United States)

Díaz-Muñoz, Samuel L

2017-01-01

Infection of more than one virus in a host, coinfection, is common across taxa and environments. Viral coinfection can enable genetic exchange, alter the dynamics of infections, and change the course of viral evolution. Yet, a systematic test of the factors explaining variation in viral coinfection across different taxa and environments awaits completion. Here I employ three microbial data sets of virus-host interactions covering cross-infectivity, culture coinfection, and single-cell coinfection (total: 6,564 microbial hosts, 13,103 viruses) to provide a broad, comprehensive picture of the ecological and biological factors shaping viral coinfection. I found evidence that ecology and virus-virus interactions are recurrent factors shaping coinfection patterns. Host ecology was a consistent and strong predictor of coinfection across all three data sets: cross-infectivity, culture coinfection, and single-cell coinfection. Host phylogeny or taxonomy was a less consistent predictor, being weak or absent in the cross-infectivity and single-cell coinfection models, yet it was the strongest predictor in the culture coinfection model. Virus-virus interactions strongly affected coinfection. In the largest test of superinfection exclusion to date, prophage sequences reduced culture coinfection by other prophages, with a weaker effect on extrachromosomal virus coinfection. At the single-cell level, prophage sequences eliminated coinfection. Virus-virus interactions also increased culture coinfection with ssDNA-dsDNA coinfections >2× more likely than ssDNA-only coinfections. The presence of CRISPR spacers was associated with a ∼50% reduction in single-cell coinfection in a marine bacteria, despite the absence of exact spacer matches in any active infection. Collectively, these results suggest the environment bacteria inhabit and the interactions among surrounding viruses are two factors consistently shaping viral coinfection patterns. These findings highlight the role of

Epidemic of cell phone virus

Science.gov (United States)

Wang, Pu; González, Marta; Barabási, Albert-László.

2008-03-01

Standard operating systems and Bluetooth technology will be a trend for future cell phone features. These will enable cell phone viruses to spread either through SMS or by sending Bluetooth requests when cell phones are physically close enough. The difference in spreading methods gives these two types of viruses' different epidemiological characteristics. SMS viruses' spread is mainly based on people's social connections, whereas the spreading of Bluetooth viruses is affected by people's mobility patterns and population distribution. Using cell phone data recording calls, SMS and locations of more than 6 million users, we study the spread of SMS and Bluetooth viruses and characterize how the social network and the mobility of mobile phone users affect such spreading processes.

SARS – virus jumps species

Indian Academy of Sciences (India)

SARS – virus jumps species. Coronavirus reshuffles genes; Rotteir et al, Rotterdam showed the virus to jump from cats to mouse cells after single gene mutation ? Human disease due to virus jumping from wild or domestic animals; Present favourite animal - the cat; - edible or domestic.

Avian influenza virus

Science.gov (United States)

Avian influenza virus (AIV) is type A influenza that is adapted to avian host species. Although the virus can be isolated from numerous avian species, the natural host reservoir species are dabbling ducks, shorebirds and gulls. Domestic poultry species (poultry being defined as birds that are rais...

Treatability evaluation of membrane technique by virus. Maku shori ni okeru shorisei hyoka to shite no virus

Energy Technology Data Exchange (ETDEWEB)

Yano, K. (Tokyo Metropolitan Research Lab. of Public Health, Tokyo (Japan))

1990-08-10

Concerning a high level treating method of regeneration of sewage water, there are methods of coagulation/precipitation, sand filtering and ozone treatment in addition to the conventional active sludge method. However, none of these methods are perfect from the viewpoint of virus. A film treating method to remove micro-organisms in water is twofold, i.e., microfiltration and reverse osmosis. For such filter treatments, polio virus is most suited as an experimental index for conducting an assessment of the treating ability of viruses. The reasons are as follows: 1. It is the smallest virus among the viruses which are mixed in the water systems. 2. Polio virus is always detected in the study of actual conditions of the viruses contained in the sewage waters. 3. It involves less danger in handling because there are vaccines which are made less poisonous. 4. Separation and quantification of viruses is easily conducted by means of cultured cells. 8 refs., 1 fig., 7 tabs.

[Epidemiologic aspects of human immunodeficiency virus and hepatitis virus infections].

Science.gov (United States)

Diarra, M; Konate, A; Minta, D; Sounko, A; Dembele, M; Toure, C S; Kalle, A; Traore, H H; Maiga, M Y

2006-01-01

In order to determinate the prevalence of hepatitis B virus and hepatitis C virus among patients infected by the HIV, We realized a transverse survey case--control in hepato-gastro-enterological ward and serology unity of National Institute of Research in Public health (INRSP). Our sample was constituted with 100 patients HIV positive compared to 100 controls HIV negative. The viral markers research has been made by methods immuno-enzymatiqueses of ELISA 3rd generation. Tests permitted to get the following results: Hepatitis B surface antigen (HBs Ag) was positive among 21% with patients HIV positive versus 23% among control (p = 0,732); Antibody to hepatitis C virus (anti-HCV ab) was present among 23% with patients HIV positive versus 0% among control (p <0,05). Female was predominant among co-infections patient, but without statistic link (p = 0,9 and p = 0,45); The co-infection HBV- HCV was significatively linked to age beyond 40 years (p = 0,0005). Co-infections with HIV infection and hepatitis virus are not rare and deserve to be investigated.

Varroa destructor Macula-like virus, Lake Sinai virus and other new RNA viruses in wild bumblebee hosts (Bombus pascuorum, Bombus lapidarius and Bombus pratorum).

Science.gov (United States)

Parmentier, Laurian; Smagghe, Guy; de Graaf, Dirk C; Meeus, Ivan

2016-02-01

Pollinators such as bumblebees (Bombus spp.) are in decline worldwide which poses a threat not only for ecosystem biodiversity but also to human crop production services. One main cause of pollinator decline may be the infection and transmission of diseases including RNA viruses. Recently, new viruses have been discovered in honeybees, but information on the presence of these in wild bumblebees is largely not available. In this study, we investigated the prevalence of new RNA viruses in Bombus species, and can report for the first time Varroa destructor Macula-like virus (VdMLV) and Lake Sinai virus (LSV) infection in multiple wild bumblebee hosts of Bombus pascuorum, Bombus lapidarius and Bombus pratorum. We sampled in 4 locations in Flanders, Belgium. Besides, we confirmed Slow bee paralysis virus (SBPV) in wild bumblebees, but no positive samples were obtained for Big Sioux river virus (BSRV). Secondly, we screened for the influence of apiaries on the prevalence of these viruses. Our results indicated a location effect for the prevalence of VdMLV in Bombus species, with a higher prevalence in the proximity of honeybee apiaries mainly observed in one location. For LSV, the prevalence was not different in the proximity or at a 1.5 km-distance of apiaries, but we reported a different isolate with similarities to LSV-2 and "LSV-clade A" as described by Ravoet et al. (2015), which was detected both in Apis mellifera and Bombus species. In general, our results indicate the existence of a disease pool of new viruses that seems to be associated to a broad range of Apoidae hosts, including multiple Bombus species. Copyright © 2015 Elsevier Inc. All rights reserved.

Autophagy in Negative-Strand RNA Virus Infection

Directory of Open Access Journals (Sweden)

Yupeng Wang

2018-02-01

Full Text Available Autophagy is a homoeostatic process by which cytoplasmic material is targeted for degradation by the cell. Viruses have learned to manipulate the autophagic pathway to ensure their own replication and survival. Although much progress has been achieved in dissecting the interplay between viruses and cellular autophagic machinery, it is not well understood how the cellular autophagic pathway is utilized by viruses and manipulated to their own advantage. In this review, we briefly introduce autophagy, viral xenophagy and the interaction among autophagy, virus and immune response, then focus on the interplay between NS-RNA viruses and autophagy during virus infection. We have selected some exemplary NS-RNA viruses and will describe how these NS-RNA viruses regulate autophagy and the role of autophagy in NS-RNA viral replication and in immune responses to virus infection. We also review recent advances in understanding how NS-RNA viral proteins perturb autophagy and how autophagy-related proteins contribute to NS-RNA virus replication, pathogenesis and antiviral immunity.

Ebola virus host cell entry.

Science.gov (United States)

Sakurai, Yasuteru

2015-01-01

Ebola virus is an enveloped virus with filamentous structure and causes a severe hemorrhagic fever in human and nonhuman primates. Host cell entry is the first essential step in the viral life cycle, which has been extensively studied as one of the therapeutic targets. A virus factor of cell entry is a surface glycoprotein (GP), which is an only essential viral protein in the step, as well as the unique particle structure. The virus also interacts with a lot of host factors to successfully enter host cells. Ebola virus at first binds to cell surface proteins and internalizes into cells, followed by trafficking through endosomal vesicles to intracellular acidic compartments. There, host proteases process GPs, which can interact with an intracellular receptor. Then, under an appropriate circumstance, viral and endosomal membranes are fused, which is enhanced by major structural changes of GPs, to complete host cell entry. Recently the basic research of Ebola virus infection mechanism has markedly progressed, largely contributed by identification of host factors and detailed structural analyses of GPs. This article highlights the mechanism of Ebola virus host cell entry, including recent findings.

Outbreaks of Influenza A Virus in Farmed Mink (Neovison vison) in Denmark: Molecular characterization of the involved viruses

DEFF Research Database (Denmark)

Larsen, Lars Erik; Breum, Solvej Østergaard; Trebbien, Ramona

mink farms with respiratory symptoms. Full-genome sequencing showed that the virus was a human/swine reassortant, with the H and N gene most related to human H3N2 viruses circulating in 2005. The remaining 6 genes were most closely related to H1N2 influenza viruses circulating in Danish swine....... This virus had not previously been described in swine, mink nor humans. PCRs assays specifically targeting the new reassortant were developed and used to screen influenza positive samples from humans and swine in Denmark with negative results. Thus, there was no evidence that this virus had spread to humans...... or was circulating in Danish pigs. In 2010 and 2011, influenza virus was again diagnosed in diseased mink in a few farms. The genetic typing showed that the virus was similar to the pandemic H1N1 virus circulating in humans and swine. The H3N2 virus was not detected in 2010 and 2011. Taken together, these findings...

Detection of selected plant viruses by microarrays

OpenAIRE

HRABÁKOVÁ, Lenka

2013-01-01

The main aim of this master thesis was the simultaneous detection of four selected plant viruses ? Apple mosaic virus, Plum pox virus, Prunus necrotic ringspot virus and Prune harf virus, by microarrays. The intermediate step in the process of the detection was optimizing of multiplex polymerase chain reaction (PCR).

Ebola Virus

Directory of Open Access Journals (Sweden)

Anusha Rangare Lakshman

2015-09-01

Full Text Available The disease Ebola takes its name from the Ebola River situated near a village in the Democratic Republic of Congo, where the disease first appeared in 1976. It is caused by a virus from the Filoviridae family (filovirus. The present outbreak of Ebola Virus Disease (EVD concerns four countries in West Africa, namely Guinea, Liberia, Sierra Leone and Nigeria till date. Further to widespread transmission of the disease, it has been declared as a Public Health Emergency of International Concern by the World Health Organisation on 8 August 2014. As of 4 August 2014, countries have reported 1,711 cases (1,070 confirmed, 436 probable, 205 suspect, including 932 deaths. This review paper enlightens about the awareness of Ebola virus and its preventive measures. [Archives Medical Review Journal 2015; 24(3.000: 296-305

A new looming of Zika virus

Institute of Scientific and Technical Information of China (English)

Nirav R Soni

2016-01-01

Zika virus (ZIKV) is a member of the virus family Flaviviridae and the genus Flavivirus, transmitted by daytime-active Aedes mosquitoes, such as A. aegypti. ZIKV will continue to spread and it will be difficult to determine how the virus will spread over time. Sign and symptoms of ZIKAVD (Zika virus disease) were conjunctivitis (red eyes), back pain, birth defect-abnormal brain development known as microcephaly and it is diagnosed through PCR (polymerase chain reaction) and virus isolation from blood samples.

Tunable protease-activatable virus nanonodes.

Science.gov (United States)

Judd, Justin; Ho, Michelle L; Tiwari, Abhinav; Gomez, Eric J; Dempsey, Christopher; Van Vliet, Kim; Igoshin, Oleg A; Silberg, Jonathan J; Agbandje-McKenna, Mavis; Suh, Junghae

2014-05-27

We explored the unique signal integration properties of the self-assembling 60-mer protein capsid of adeno-associated virus (AAV), a clinically proven human gene therapy vector, by engineering proteolytic regulation of virus-receptor interactions such that processing of the capsid by proteases is required for infection. We find the transfer function of our engineered protease-activatable viruses (PAVs), relating the degree of proteolysis (input) to PAV activity (output), is highly nonlinear, likely due to increased polyvalency. By exploiting this dynamic polyvalency, in combination with the self-assembly properties of the virus capsid, we show that mosaic PAVs can be constructed that operate under a digital AND gate regime, where two different protease inputs are required for virus activation. These results show viruses can be engineered as signal-integrating nanoscale nodes whose functional properties are regulated by multiple proteolytic signals with easily tunable and predictable response surfaces, a promising development toward advanced control of gene delivery.

Virus detection and quantification using electrical parameters

Science.gov (United States)

Ahmad, Mahmoud Al; Mustafa, Farah; Ali, Lizna M.; Rizvi, Tahir A.

2014-10-01

Here we identify and quantitate two similar viruses, human and feline immunodeficiency viruses (HIV and FIV), suspended in a liquid medium without labeling, using a semiconductor technique. The virus count was estimated by calculating the impurities inside a defined volume by observing the change in electrical parameters. Empirically, the virus count was similar to the absolute value of the ratio of the change of the virus suspension dopant concentration relative to the mock dopant over the change in virus suspension Debye volume relative to mock Debye volume. The virus type was identified by constructing a concentration-mobility relationship which is unique for each kind of virus, allowing for a fast (within minutes) and label-free virus quantification and identification. For validation, the HIV and FIV virus preparations were further quantified by a biochemical technique and the results obtained by both approaches corroborated well. We further demonstrate that the electrical technique could be applied to accurately measure and characterize silica nanoparticles that resemble the virus particles in size. Based on these results, we anticipate our present approach to be a starting point towards establishing the foundation for label-free electrical-based identification and quantification of an unlimited number of viruses and other nano-sized particles.