CONGENITAL ANOMALIES, Issue 3 2005
Yukiko Kagohashi
ABSTRACT Type 1 diabetes results from the destruction of pancreatic b-cells (insulitis). It is a multifactorial disease involving genetic and environmental factors, including the maternal environment. Viruses have also been implicated in the pathogenesis of human type 1 diabetes as well as in its model non-obese diabetic (NOD) mice during the perinatal period, as endogenous viruses and/or as infectious agents vertically transmitted from mothers. However, the role of virus as genetic or environmental factor and its interaction with other maternal factors remain unclear. In a series of experiments, we transplanted preimplantation-stage NOD embryos into the uterus of recipient Institute of Cancer Research (ICR) mice, which are without diabetic genetic predisposition, and NOD mice, which did not exhibit overt diabetes during the experiment, and designated offspring as NOD/ICR and NOD/NOD, respectively. We previously observed that NOD/ICR offspring developed insulitis significantly earlier than NOD/NOD offspring. To assess the role of viruses in the development of insulitis, we examined the appearance of viral particles and expression of retroviruses between NOD/ICR and NOD/NOD. NOD/ICR showed earlier expression of env region of the xenotropic type C retrovirus by polymerase chain reaction analysis than NOD/NOD, while the retrovirus-like particles were observed in the islet b-cells similarly in both groups by electron microscopy. Serum corticosterone level, which is suggested to enhance retroviral induction, was significantly higher in the ICR than in the NOD surrogate mothers. These findings suggest that the observed virus is endogenous and that maternal environmental factors, including hormone levels, affect the induction of endogenous viruses and cause the earlier onset of insulitis. [source]

A new look at viruses in type 1 diabetes

DIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 1 2003
Hee-Sook Jun
Abstract Type 1 diabetes (T1D) results from the destruction of pancreatic beta cells. Genetic factors are believed to be a major component for the development of T1D, but the concordance rate for the development of diabetes in identical twins is only about 40%, suggesting that nongenetic factors play an important role in the expression of the disease. Viruses are one environmental factor that is implicated in the pathogenesis of T1D. To date, 14 different viruses have been reported to be associated with the development of T1D in humans and animal models. Viruses may be involved in the pathogenesis of T1D in at least two distinct ways: by inducing beta cell-specific autoimmunity, with or without infection of the beta cells, [e.g. Kilham rat virus (KRV)] and by cytolytic infection and destruction of the beta cells (e.g. encephalomyocarditis virus in mice). With respect to virus-mediated autoimmunity, retrovirus, reovirus, KRV, bovine viral diarrhoea-mucosal disease virus, mumps virus, rubella virus, cytomegalovirus and Epstein-Barr virus (EBV) are discussed. With respect to the destruction of beta cells by cytolytic infection, encephalomyocarditis virus, mengovirus and Coxsackie B viruses are discussed. In addition, a review of transgenic animal models for virus-induced autoimmune diabetes is included, particularly with regard to lymphocytic choriomeningitis virus, influenza viral proteins and the Epstein-Barr viral receptor. Finally, the prevention of autoimmune diabetes by infection of viruses such as lymphocytic choriomeningitis virus is discussed. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Crash of a population of the marine heterotrophic flagellate Cafeteria roenbergensis by viral infection

ENVIRONMENTAL MICROBIOLOGY, Issue 11 2007
Ramon Massana
Summary Viruses are known as important mortality agents of marine microorganisms. Most studies focus on bacterial and algal viruses, and few reports exist on viruses infecting marine heterotrophic protists. Here we show results from several incubations initiated with a microbial assemblage from the central Indian Ocean and amended with different amounts of organic matter. Heterotrophic flagellates developed up to 30 000 cells ml,1 in the most enriched incubation. A 18S rDNA clone library and fluorescent in situ hybridization counts with newly designed probes indicated that the peak was formed by Cafeteria roenbergensis and Caecitellus paraparvulus (90% and 10% of the cells respectively). Both taxa were below detection in the original sample, indicating a strong positive selective bias during the enrichment. During the peak, C. roenbergensis cells were observed with virus-like particles in the cytoplasm, and 4 days later this taxa could not be detected. Transmission electron microscopy confirmed the viral nature of these particles, which were large (280 nm), had double-stranded DNA, and were produced with a burst size of ,70. This virus was specific of C. roenbergensis as neither C. paraparvulus that was never seen infected, nor other flagellate taxa that developed in later stages of the incubation, appeared attacked. This is one of the few reports on a heterotrophic flagellate virus and the implications of this finding in the Indian Ocean are discussed. [source]

Grazer and virus-induced mortality of bacterioplankton accelerates development of Flectobacillus populations in a freshwater community

ENVIRONMENTAL MICROBIOLOGY, Issue 3 2007
Karel, imek
Summary We present a detailed analysis of the effects of distinct bacterial mortality factors, viral lysis and heterotrophic nanoflagellates (HNF) bacterivory, associated with the development of filamentous Flectobacillus populations. Reservoir bacterioplankton communities were subjected to additions of both HNF and viruses together, or HNF alone, and then incubated in situ in dialyses bags. For distinct bacterial groups, mortality or growth stimulation was analysed by examining bacterial prey ingested in HNF food vacuoles with fluorescence in situ hybridization (FISH) and via FISH with microautoradiography (MAR-FISH). We also developed a semi-quantitative MAR-FISH-based estimation of relative activities of Flectobacillus populations (targeted by the R-FL615 probe). Bacterial groups vulnerable to HNF predation (mainly clusters of Betaproteobacteria), or discriminated against (Actinobacteria), were detected. Bacterial lineages most vulnerable to virus-lysis (mainly the Betaproteobacteria not targeted by the R-BT065 probe, of the Polynucleobacter cluster) were identified by comparing treatments with HNF alone to HNF and viruses together. Filaments affiliated with the Flectobacillus cluster appeared in both treatments, but were about twice as abundant, long and active as in incubations with viruses and HNF as compared with HNF alone. Viruses appeared to selectively suppress several bacterial groups, perhaps enhancing substrate availability thus stimulating growth and activity of filamentous Flectobacillus. [source]

Viruses of grapevine in Syria

EPPO BULLETIN, Issue 3 2006
T. Mslmanieh
Surveys for virus and virus-like diseases were carried out in commercial vineyards and nurseries in seven different Syrian provinces (Aleppo, Dara'a, As Suwayda, Al Qunaytirah, Homs, Hamah, Tartous). Samples were collected at random from 835 individual vines (735 Vitis vinifera and 100 rootstock accessions) for laboratory testing. Grapevine fanleaf virus (GFLV), Arabis mosaic virus (ArMV), and Grapevine virus A (GVA) were the only viruses recovered by mechanical transmission to herbaceous hosts. Vein necrosis developed in c. 53% of graft-inoculated 110R indicators and vein mosaic in V. riparia inoculated with material from cv. Corna Alegra. A total of 71% of the ELISA-tested V. vinifera plants (522 out of 735) were infected by one (14.8%) or more (55.8%) viruses. GVA was the most widespread (54.7%), followed by Grapevine leafroll-associated virus 1 (GLRaV-1, 47.3%), Grapevine fleck virus (GFkV, 29.7%), and Grapevine leafroll-associated virus 3 (GLRaV-3, 23.9%). Other economically relevant viruses were scarcer, i.e. Grapevine leafroll-associated virus 2 (GLRaV-2, 9%), GFLV (0.8%) and ArMV (0.1%). The most important Syrian grapevine varieties, i.e. Hellwany, Salty, Balady, and Zeiny, had average infection rates that ranged between 44% and 91%. The highest incidence of infections was observed at Damascus (90%), whereas it ranged between 68% and 79% in the other provinces, except for Hama (36%). Rootstocks were in much better sanitary condition (25% infection). GFkV (22%) was the most common virus, whilst the presence of GLRaV-3 (3%), GLRaV-1, and GFLV (1%) was negligible. Grapevine rupestris stem pitting associated virus (GRSPaV) was detected in 72.3% of the samples by RT-PCR. A high percentage of the GRSPaV-positive vines (80%) induced vein necrosis reactions in 110R, thus confirming the recently established correlation between this virus and vein necrosis. [source]

Viruses of pome fruit trees in Syria

EPPO BULLETIN, Issue 1 2006
F. Ismaeil
A survey was conducted to evaluate the sanitary status of pome fruit trees in Syria during spring 2003 and 2004 in 6 governorates: Damascus, Al-Qunaitara and Al-Sweida (Southern region), Homs and Hama (Central region) and Latakia (Costal Western region), as the main production areas of pome fruits. Leaf samples from 1077 apples, 54 pears and 14 quince were collected and tested for the presence of Apple chlorotic leaf spot virus (ACLSV), Apple stem grooving virus (ASGV) and Apple mosaic virus (ApMV) in 70 commercial orchards and 3 varietal collections by ELISA. Results showed that the virus infection rates were 34 and 2% in apple and pear, respectively. Quince trees were found to be virus tested free. ACLSV was prevailing on apple with 34%, whereas ASGV and ApMV were found in 2 and 0.2% of tested trees, respectively. Pear trees were infected only with ACLSV (2%). 21 apples and 15 pears representative budwood samples were indexed by grafting on the following indicators: (i) Malus pumila cvs. Virginia Crab and Radiant for apple and (ii) M. pumila cv. V. Crab and Pyrus communis cv. Nouveau Poiteau for pear. The virus infection rates by woody indexing were much higher than ELISA, Apple stem pitting virus (ASPV) and ASGV were found in 86 and 82% of apple tested samples, whereas they were 80 and 60% of pear tested samples, respectively. Additional RT-PCR testing carried out for a limited number of samples confirmed the high incidence of ACLSV ASPV, ASGV and the presence of ApMV. This is the first report on pome fruit viruses in Syria, indicating an unsatisfactory sanitary status of the industry. As a consequence, a certification program is recommended for producing locally healthy propagating material. [source]

Viruses of vegetable crops in Albania

EPPO BULLETIN, Issue 3 2005
M. Finetti-Sialer
Field surveys were carried out in the main vegetable-growing areas of Western and Central Albania to evaluate the sanitary status of open-field and protected cultivations of capsicum, tomato, potato, watermelon, cucumber, courgette, aubergine, lettuce, cabbage, chicory, leek and celery. The following viruses were detected: Alfalfa mosaic alfamovirus (AMV), Cucumber mosaic cucumovirus (CMV), Potato Y potyvirus (PVY), Tomato spotted wilt tospovirus (TSWV) and Watermelon mosaic potyvirus 2 (WMV-2). The virus found most frequently was CMV and all the isolates identified were of subgroup IA. AMV was also detected in several areas and all isolates were of subgroup II, suggesting a French origin. Finally, at the time of this survey, TSWV infections appeared to be moderately relevant and absent in protected crops. This is the first documented record of AMV, CMV, PVY, TSWV and WMV-2 in Albania. No infection by Tomato yellow leaf curl begomovirus (TYLCV) or Zucchini yellow mosaic potyvirus (ZYMV) was detected during this survey. [source]

Freshwater and marine virioplankton: a brief overview of commonalities and differences

FRESHWATER BIOLOGY, Issue 6 2008
STEVEN W. WILHELM
Summary 1. Viruses are a pervasive component of microbial food webs in both marine and freshwater systems. The abundance of viruses in individual aquatic systems appears to be independent of salinity but related to the biomass of primary and secondary producers as well as seasonal effects. Burst size, virus production rate and the percentage of microbial cells carrying a viral burden also appear to be more closely correlated to trophic status than to salinity. 2. In marine environments, the roles of planktonic viruses as regulators of carbon and nutrient cycling as well as microbial community structure have been a focus of numerous studies, yet the roles of freshwater virioplankton remain much less studied. Nevertheless, a survey of published freshwater studies demonstrates that virioplankton recycle important quantities of growth-limiting nutrients from hosts via generation of dead particulate and dissolved organic matter during cell lysis, and suggests that both the chemical speciation and concentration of these organic compounds and nutrients may have important influences on the microbial community. 3. Parallel observations on the spatial patterns and dynamics of microbial mortality due to viruses or grazing are more advanced in freshwaters than in marine environments. However, the constraints that determine whether virus- or grazer-mediated mortality dominates are not yet understood in either environment. 4. Application of molecular approaches has facilitated the examination of the diversity and ecological dynamics of specific viral populations and entire communities. The depth of detail achieved in marine environments towards characterizing these populations and communities is just beginning to be matched in freshwater systems. The few available data suggest that viruses targeting-related hosts in freshwater and marine systems may be genetically distinct. 5. Although the role of viruses in aquatic systems is complex and remains insufficiently studied, our survey of the literature indicates that, despite some differences, many of the controls on virioplankton activity and diversity are similar in marine and freshwater environments. [source]

Liquid Crystal Emulsions as the Basis of Biological Sensors for the Optical Detection of Bacteria and Viruses

ADVANCED FUNCTIONAL MATERIALS, Issue 14 2009
Sri Sivakumar
Abstract A versatile sensing method based on monodisperse liquid crystal (LC) emulsion droplets detects and distinguishes between different types of bacteria (Gram +ve and ,ve) and viruses (enveloped and non-enveloped). LCs of 4-cyano-4'-pentylbiphenyl transition from a bipolar to radial configuration when in contact with Gram ,ve bacteria (E. coli) and lipid-enveloped viruses (A/NWS/Tokyo/67). This transition is consistent with the transfer of lipid from the organisms to the interfaces of the micrometer-sized LC droplets. In contrast, a transition to the radial configuration is not observed in the presence of Gram +ve bacteria (Bacillus subtilis and Micrococcus luteus) and non-enveloped viruses (M13 helper phage). The LC droplets can detect small numbers of E. coli bacteria (1,5) and low concentrations (104,pfu mL,1) of A/NWS/Tokyo/67 virus. Monodisperse LC emulsions incubated with phosholipid liposomes (similar to the E. coli cell wall lipid) reveal that the orientational change is triggered at an area per lipid molecule of ,46,Å2 on an LC droplet (,1.6,×,108 lipid molecules per droplet). This approach represents a novel means to sense and differentiate between types of bacteria and viruses based on their cell-wall/envelope structure, paving the way for the development of a new class of LC microdroplet-based biological sensors. [source]

Cover Picture: Assembly of Wiseana Iridovirus: Viruses for Colloidal Photonic Crystals (Adv. Funct.

ADVANCED FUNCTIONAL MATERIALS, Issue 8 2006
Mater.
Abstract Assembly of colloids is a versatile tool for micro- and nanofabrication. Natural and artificially engineered viruses offer the opportunity to expand the functionality and versatility of such assemblies. The cover shows optically iridescent, thin polycrystalline arrays (background) as well as bulk pellets (inset right) that exhibit reversible hydration-dependent reflection spectra, as reported by Vaia and co-workers on p.,1086. The films and pellets were created in vitro with classical colloid-assembly techniques from Wiseana iridescent virus (inset, center) harvested from infected Wiseana spp larvae (inset, left). In,vitro assembly of Wiseana iridescent virus (WIV) yields iridescent pellets and films with structural color more vivid than in the native insect. WIV is icosahedral in shape, 140,nm in diameter, with 30,nm long fibrils attached to the outer surface, and exhibits a surface charge ca.,1/6th that of a comparable polymer colloid. The low surface charge and tethered chains on the virus surface allow the facile modification of the interparticle distance. Directed sedimentation yields predominantly an amorphous liquid-like packing of the virus. Such samples exhibit a broad reflection band that is angle independent and for which the broad maximum can be reversibly shifted from blue towards red with increased hydration. Slow sedimentation and flow-assisted assembly methods produce thin films with a polycrystalline morphology that exhibit narrower, more intense reflectivity peaks, which are hydration and angle dependent. This study points toward the potential of viral particles for photonic crystals where their unique structural features (icosahedral symmetry, extreme monodispersity, precise surface functionalization, and tethered surface chains of low surface-charge density) may lead to superior control of optical properties of their assembled arrays. [source]

Large-Scale Arrays of Aligned Single Viruses

ADVANCED MATERIALS, Issue 1 2010
Daniel J. Solis
The fabrication of single virus arrays is demonstrated using direct printing of unmodified anti-M13 bacteriophage antibodies onto silicon with nanometer resolution (see image), widely variable feature pitch, and flow alignment of the viruses. Organization of virus-based systems into functional, addressable arrays has many technological applications including microarray technology and bottom-up nanoassemblies. [source]

Protective effect of single-dose adjuvanted pandemic influenza vaccine in children

INFLUENZA AND OTHER RESPIRATORY VIRUSES, Issue 4 2010
P. G. Van Buynder
Please cite this paper as: Van Buynder et al. (2010) Protective effect of single-dose adjuvanted pandemic influenza vaccine in children. Influenza and Other Respiratory Viruses 4(4), 171,178. Background, During the first wave of A/California/7/2009(H1N1) influenza, high rates of hospitalization in children under 5 years were seen in many countries. Subsequent policies for vaccinating children varied in both type of vaccine and number of doses. In Canada, children 36 months to <10 years received a single dose of 0·25 ml of the GSK adjuvanted vaccine (ArepanrixÔ) equivalent to 1·9 ,g HA. Children 6 months to 35 months received two doses as did those 36,119 months with chronic medical conditions. Method, We conducted a community-based case,control vaccine effectiveness (VE) review of children under 10 years with influenza like illness who were tested for H1N1 infection at the central provincial laboratory. Laboratory-confirmed influenza was the primary outcome, and vaccination status the primary exposure to assess VE after a single 0·25-ml dose. Results, If vaccination was designated to be effective after 14 days, no vaccinated child had laboratory-confirmed influenza compared to 38% of controls. The VE of 100% was statistically significant for children <10 years of age and <5 years considered separately. If vaccination was considered effective after 10 days, VE dropped to 96% overall but was statistically significant and over 90% in all age subgroups, including those under 36 months. Conclusions, A single 0·25-ml dose of the GSK adjuvanted vaccine (ArepanrixÔ) protects children against laboratory-confirmed pandemic influenza potentially avoiding any increased reactogenicity associated with second doses. Adjuvanted vaccines offer hope for improved seasonal vaccines in the future. [source]

An epidemiological analysis of severe cases of the influenza A (H1N1) 2009 virus infection in Japan

INFLUENZA AND OTHER RESPIRATORY VIRUSES, Issue 4 2010
Koji Wada
Please cite this paper as: Wada et al. (2010). An epidemiological analysis of severe cases of the influenza A (H1N1) 2009 virus infection in Japan. Influenza and Other Respiratory Viruses 4(4), 179,186. Background, The age distribution of confirmed cases with influenza A (H1N1) 2009 has shifted toward children and young adults, in contrast to interpandemic influenza, because of the age specificities in immunological reactions and transmission characteristics. Objectives, Descriptive epidemiological analysis of severe cases in Japan was carried out to characterize the pandemic's impact and clinical features. Methods, First, demographic characteristics of hospitalized cases (n = 12 923), severe cases (n = 894) and fatal cases (n = 116) were examined. Second, individual records of the first 120 severe cases, including 23 deaths, were analyzed to examine potential associations of influenza death with demographic variables, medical treatment and underlying conditions. Among severe cases, we compared proportions of specific characteristics of survivors with those of fatal cases to identify predictors of death. Results, Age distribution of hospitalized cases shifted toward those aged <20 years; this was also the case for deaths without underlying medical conditions. Deaths in adults were mainly seen among those with underlying medical conditions, resulting in an increased risk of death as a function of age. According to individual records, the time from onset to death in Japan appeared rather short compared with that in other countries. Conclusion, The age specificity of severe cases and their underlying medical conditions were consistent with other countries. To identify predictors of death in influenza A (H1N1) 2009 patients, more detailed clinical characteristics need to be examined according to different age groups and types of manifestations, which should ideally include mild cases as subjects. [source]

Serologic survey of swine workers for exposure to H2N3 swine influenza A

INFLUENZA AND OTHER RESPIRATORY VIRUSES, Issue 3 2010
Amanda Beaudoin
Please cite this paper as: Beaudoin et al. (2010) Serologic survey of swine workers for exposure to H2N3 swine influenza A. Influenza and Other Respiratory Viruses 4(3), 163,170. Background, Of the 16 influenza A hemagglutinin (H) subtypes, only H1, H2 and H3 viruses have been shown to cause sustained human infection. Whereas H1 and H3 viruses currently circulate seasonally in humans, H2 viruses have not been identified in humans since 1968. In 2006, an H2N3 influenza virus was isolated from ill swine in the United States. Objective, To assess the potential for zoonotic influenza transmission, the current study looked for serologic evidence of H2 influenza infection among workers at two swine facilities, some exposed and some unexposed to H2N3-positive pigs. Methods, The sera were assessed for antibodies to swine H2 influenza and currently circulating seasonal human influenza A subtypes H1N1 and H3N2. Workers were interviewed to obtain details such as age, influenza vaccination history, experiences of influenza-like-illness, and use of personal protective equipment and hygiene when working with pigs. Exposure and risk factors for positive antibody titers were compared for exposed and unexposed individuals as well as for H2 antibody-positive and H2 antibody-negative individuals. Results, Blood was taken from 27 swine workers, of whom four had positive H2 antibody titers (,1:40). Three of the positive employees were born before 1968 and one had an unknown birth date. Only one of these workers had been exposed to H2N3-positive pigs, and he was born in 1949. Conclusions, These data do not support the hypothesis that swine workers were infected with the emergent swine H2N3 influenza A virus. [source]

An early report from newly established laboratory-based influenza surveillance in Lao PDR

INFLUENZA AND OTHER RESPIRATORY VIRUSES, Issue 2 2010
Phengta Vongphrachanh
Please cite this paper as: Vongphrachanh P, Simmerman JM, Phonekeo D, Pansayavong V, Sisouk T, Ongkhamme S, Bryce GT, Corwin A, Bryant JE. An early report from newly established laboratory-based influenza surveillance in Lao PDR. Influenza and Other Respiratory Viruses 4(2), 47,52. Background, Prior to 2007, little information was available about the burden of influenza in Laos. We report data from the first laboratory-based influenza surveillance system established in the Lao People's Democratic Republic. Methods, Three hospitals in the capital city of Vientiane began surveillance for influenza-like illness (ILI) in outpatients in 2007 and expanded to include hospitalized pneumonia patients in 2008. Nasal/throat swab specimens were collected and tested for influenza and other respiratory viruses by multiplex ID-TagTM respiratory viral panel (RVP) assay on a Luminex® 100× MAP IS instrument (Qiagen, Singapore). Results, During January 2007 to December 2008, 287 of 526 (54·6%) outpatients with ILI were positive for at least one respiratory virus. Influenza was most commonly identified, with 63 (12·0%) influenza A and 92 (17·5%) influenza B positive patients identified. In 2008, six of 79 (7·6%) hospitalized pneumonia patients were positive for influenza A and four (5·1%) were positive for influenza B. Children <5 years represented 19% of viral infections in outpatients and 38% of pneumonia inpatients. Conclusion, Our results provide the first documentation of influenza burden among patients with febrile respiratory illness and pneumonia requiring hospitalization in Laos. Implementing laboratory-based influenza surveillance requires substantial investments in infrastructure and training. However, continuing outbreaks of avian influenza A/H5N1 in poultry and emergence of the 2009 influenza A(H1N1) pandemic strain further underscore the importance of establishing and maintaining influenza surveillance in developing countries. [source]

International Society for Influenza and other Respiratory Viruses and the new journal

INFLUENZA AND OTHER RESPIRATORY VIRUSES, Issue 1 2007
Geoffrey C. Schild
[source]

Nanoindentation Studies Reveal Material Properties of Viruses

ADVANCED MATERIALS, Issue 10-11 2009
Wouter H. Roos
Abstract Over the last years, a paradigm shift has occurred from approaching viruses solely as disease-bringing agents toward regarding them as functional nanoparticles, and a perfect example of Nature's capability to self-assemble complex, multicomponent materials at the nanoscale. Viruses are now used as templates for constructing specific nanocontainers, either by changing the properties of the viruses themselves or by copying their compact, shelled structure into engineered materials, which are able to encapsulate various agents. To exploit the mechanisms used by nature to create functional nanocontainers, we need to understand what their material and biomechanical properties are. Nanoindentation, a technique based on atomic force microscopy, is perfectly suited to determine these characteristics. Here, we discuss the advances this research field has achieved, exploring prokaryotic (bacteriophages) as well as eukaryotic viruses. The material properties of viral shells (capsids) and of more complex viral assemblies are analyzed and compared. We discuss the Young's modulus of capsids, the maximal forces viruses can withstand, and explore the occurrence of material fatigue in nanosize objects. Finally, the impact of internalized materials and of specific alterations to the capsid proteins on the particle's mechanical strength is analyzed. [source]

Nanocomposite Films Assembled from Genetically Engineered Filamentous Viruses and Gold Nanoparticles: Nanoarchitecture- and Humidity-Tunable Surface Plasmon Resonance Spectra

ADVANCED MATERIALS, Issue 9 2009
Aihua Liu
Nanocomposite films are prepared by layer-by-layer (LBL) assembly of cationic genetically engineered rodlike nontoxic viruses and anionic spherical Au nanoparticles. The cationic viruses electrostatically interact with the anionic Au nanoparticles to drive the LBL assembly. The nanocomposite films exhibit humidity-dependent surface plasmon resonance spectra (see figure). [source]

Viral escape mechanisms , escapology taught by viruses

INTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 5 2001
Michaela Lucas
Viruses have ,studied' immunology over millions of years of coevolution with their hosts. During this ongoing education they have developed countless mechanisms to escape from the host's immune system. To illustrate the most common strategies of viral immune escape we have focused on two murine models of persistent infection, lymphocytic choriomeningitis virus (LCMV) and murine cytomegalovirus (MCMV).LCMV is a fast replicating small RNA virus with a genome prone to mutations. Therefore, LCMV escapes from the immune system mainly by two strategies: ,speed' and ,shape change'. At the opposite extreme, MCMV is a large, complex DNA virus with a more rigid genome and thus the strategies used by LCMV are no option. However, MCMV has the coding capacity for additional genes which interfere specifically with the immune response of the host. These escape strategies have been described as ,camouflage' and ,sabotage'. Using these simple concepts we describe the spectrum of viral escapology, giving credit not only to the researchers who uncovered this fascinating area of immunology but also to the viruses themselves, who still have a few lessons to teach. [source]

Viral exanthems in childhood.

JOURNAL DER DEUTSCHEN DERMATOLOGISCHEN GESELLSCHAFT, Issue 6 2009
Part 3: Parainfectious exanthems, those associated with virus-drug interactions
Summary Viruses cause not only direct infectious exanthems, but also parainfectious exanthems, which provoke skin alterations via interactions with the immune system. These distinct exanthems, for instance Gianotti-Crosti syndrome and pityriasis lichenoides group, do not reflect a specific pathogen but can occur in the course of many viral infections. In addition, some exanthems result from the interaction between viruses and drugs. [source]

Isoelectric points of viruses

JOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2010
B. Michen
Summary Viruses as well as other (bio-)colloids possess a pH-dependent surface charge in polar media such as water. This electrostatic charge determines the mobility of the soft particle in an electric field and thus governs its colloidal behaviour which plays a major role in virus sorption processes. The pH value at which the net surface charge switches its sign is referred to as the isoelectric point (abbreviations: pI or IEP) and is a characteristic parameter of the virion in equilibrium with its environmental water chemistry. Here, we review the IEP measurements of viruses that replicate in hosts of kingdom plantae, bacteria and animalia. IEPs of viruses are found in pH range from 1·9 to 8·4; most frequently, they are measured in a band of 3·5 < IEP < 7. However, the data appear to be scattered widely within single virus species. This discrepancy is discussed and should be considered when IEP values are used to account for virus sorption processes. [source]

Viral appropriation of apoptotic and NF-,B signaling pathways

JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2004
Andrew G. Bowie
Abstract Viruses utilize a variety of strategies to evade the host immune response and replicate in the cells they infect. The comparatively large genomes of the Orthopoxviruses and gammaherpesviruses encode several immunomodulatory proteins that are homologous to component of the innate immune system of host cells, which are reviewed here. However, the viral mechanisms used to survive host responses are quite distinct between these two virus families. Poxviruses undergo continuous lytic replication in the host cytoplasm while expressing many genes that inhibit innate immune responses. In contrast, herpesviruses persist in a latent state during much of their lifecycle while expressing only a limited number of relatively non-immunogenic viral proteins, thereby avoiding the adaptive immune response. Poxviruses suppress, whereas latent gammaherpesviruses activate, signaling by NF-,B, yet both viruses target similar host signaling pathways to suppress the apoptotic response. Here, modulation of apoptotic and NF-,B signal transduction pathways are examined as examples of common pathways appropriated in contrasting ways by herpesviruses and poxviruses. © 2004 Wiley-Liss, Inc. [source]

Iridovirus infections in finfish , critical review with emphasis on ranaviruses

JOURNAL OF FISH DISEASES, Issue 2 2010
R J Whittington
Abstract Viruses in three genera of the family Iridoviridae (iridoviruses) affect finfish. Ranaviruses and megalocytiviruses are recently emerged pathogens. Both cause severe systemic disease, occur globally and affect a diversity of hosts. In contrast, lymphocystiviruses cause superficial lesions and rarely cause economic loss. The ranavirus epizootic haematopoietic necrosis virus (EHNV) from Australia was the first iridovirus to cause epizootic mortality in finfish. Like other ranaviruses, it lacks host specificity. A distinct but closely related virus, European catfish virus, occurs in finfish in Europe, while very similar ranaviruses occur in amphibians in Europe, Asia, Australia, North America and South America. These viruses can be distinguished from one another by conserved differences in the sequence of the major capsid protein gene, which informs policies of the World Organisation for Animal Health to minimize transboundary spread of these agents. However, limited epidemiological information and variations in disease expression create difficulties for design of sampling strategies for surveillance. There is still uncertainty surrounding the taxonomy of some putative ranaviruses such as Singapore grouper iridovirus and Santee-Cooper ranavirus, both of which cause serious disease in fish, and confusion continues with diseases caused by megalocytiviruses. In this review, aspects of the agents and diseases caused by ranaviruses are contrasted with those due to megalocytiviruses to promote accurate diagnosis and characterization of the agents responsible. Ranavirus epizootics in amphibians are also discussed because of possible links with finfish and common anthropogenic mechanisms of spread. The source of the global epizootic of disease caused by systemic iridoviruses in finfish and amphibians is uncertain, but three possibilities are discussed: trade in food fish, trade in ornamental fish, reptiles and amphibians and emergence from unknown reservoir hosts associated with environmental change. [source]

Mucosal challenge of Macaca nemestrina with simian immunodeficiency virus (SIV) following SIV nucleocapsid mutant DNA vaccination*

JOURNAL OF MEDICAL PRIMATOLOGY, Issue 3-4 2000
Robert J. Gorelick
A simian immunodeficiency virus (SIV)(Mne) DNA clone was constructed that produces viruses containing a four amino acid deletion in the second zinc finger of the nucleocapsid (NC) domain of the Gag polyprotein. Viruses produced from this clone, although non-infectious both in vitro and in vivo, complete a majority of the steps in a single retroviral infection cycle. Eight pig-tailed macaques (Macaca nemestrina) were inoculated intramuscularly and subcutaneously three times over the course of 24 weeks with the NC mutant expressing DNA. These macaques, and four controls, were then challenged mucosally (intrarectally) with the homologous virus (SIV Mne CL E11S) and monitored for evidence of infection and clinical disease. Prior to challenge, a measurable humoral immune response was noted in four of eight immunized macaques. After challenge, all 12 macaques became infected, although four immunized animals greatly restricted their viral replication, and one immunized animal that controlled replication remains antibody negative. No disease has been evidence during the 46-week period of monitoring after challenge. [source]

Molecular typing and epidemiology of non-polio enteroviruses isolated from Yunnan Province, the People's Republic of China

JOURNAL OF MEDICAL VIROLOGY, Issue 4 2008
Tian Bingjun
Abstract This report presents an overview of human enteroviruses in Yunnan Province, the People's Republic of China. A total of 210 non-polioviruses isolated under acute flaccid paralysis (AFP) surveillance during a total study period of 5 years,1997 to 2000 and 2004,were examined. Of the 210 non-poliovirus isolates, 12 adenoviruses were serologically identified, and the remaining 198 isolates were used for molecular typing. The viral genomes of 195 non-polio enteroviruses (NPEVs) on VP1 partial region of virus capsid were translated to the corresponding amino acid sequences; these were compared with those of prototype strains. Based on molecular typing, 5 isolates were classified into 5 serotypes of the human enterovirus A species, 158 isolates, into 35 serotypes of the human enterovirus B species; and 32 isolates, into 6 serotypes of the human enterovirus C species. Viruses belonging to the human enterovirus D species were not isolated. Thus, under AFP surveillance, the human enterovirus B species accounted for 75.2% of the 210 isolates, and it was considered the predominant species. This was followed by human enterovirus C (12.2%), adenovirus (5.7%), and human enterovirus A (2.4%). Further, molecular analysis suggested that several serotypes of human enteroviruses B and C that exhibited genetic polymorphism were indigenous. Molecular typing methods may aid in understanding the epidemiology of NPEVs in Yunnan Province. J. Med. Virol. 80:670,679, 2008. © 2008 Wiley-Liss, Inc. [source]

Detection of viruses identified recently in children with acute wheezing

JOURNAL OF MEDICAL VIROLOGY, Issue 8 2007
Ju-Young Chung
Abstract The etiologic role of recently identified respiratory viruses for acute wheezing in children is not yet clear. The purpose of this study was to investigate the prevalence of recently identified viruses, including human metapneumovirus (hMPV), human bocavirus (hBoV), human coronavirus NL63 (hCoV-NL63), and human coronavirus HKU1 (hCoV-HKU1) in children with acute wheezing. Viral etiology was identified in 231 children hospitalized with acute wheezing, aged from 1 month to 5 years. Viral antigens for common respiratory viruses were detected by IFA or multiplex PCR. RT-PCR was used to detect respiratory rhinoviruses, hCoV-NL63, hCoV-HKU1, and hMPV. PCR assays for hBoV DNA were performed using the primer sets for noncapsid protein (NP1) and nonstructural protein (NS1) genes. Viruses were found in 61.5% (142/231) of the study population and a single virus was detected in 45.5% (105/231) of the study population. Rhinovirus (33.3%), human respiratory syncytial virus (hRSV; 13.8%), and hBoV (13.8%) were the most frequently detected viruses. hMPV and hCoV-NL63 were detected in 7.8% and 1.3% of wheezing children, respectively. HCoV-HKU1 was not detected. In 16.0% of the study population, more than one virus was detected. In children with acute wheezing, rhinovirus, hRSV, and hBoV were most frequently detected. Further studies including healthy control subjects are needed to define the clinical significance of hBoV in acute wheezing. J. Med. Virol. 79: 1238,1243, 2007. © 2007 Wiley-Liss, Inc. [source]

Characterization of tick-borne encephalitis virus from latvia: Evidence for co-circulation of three distinct subtypes

JOURNAL OF MEDICAL VIROLOGY, Issue 4 2001
Åke Lundkvist
Abstract Viruses of the tick-borne encephalitis (TBE) antigenic complex within the family Flaviviridae cause a variety of diseases, including uncomplicated febrile illness, meningoencephalitis, and hemorrhagic fever. Different domesticated animals or wildlife species often act as reservoir hosts and ixodid ticks serve as vectors. Although TBE is a serious problem in Latvia, the knowledge concerning TBE virus (TBEV) strains circulating in the country is most limited. Only two strains (Latvia-1-96 isolated from a TBE patient, and RK1424 originating from an Ixodes persulcatus tick), which belonged to the Siberian and the Far Eastern subtypes of TBEV, respectively, have previously been characterized. In the present study, we concentrated on the western and central regions of Latvia, with predominantly Ixodes ricinus ticks. Five virus strains were isolated from serum samples of patients with clinical symptoms of an acute TBE infection. Nucleotide sequences encoding the envelope (E) protein of TBEV, which were recovered from the five TBEV isolates, showed the highest level of identity to the corresponding sequences of the prototype strain Neudoerfl and other European strains of the Western TBEV subtype characterized previously. Accordingly, phylogenetic analysis placed the new Latvian isolates within the Western genetic lineage of TBEV. Taken together with earlier observations, the results proved that all three TBEV subtypes are co-circulating in Latvia and indicated that the genetic diversity of TBEV within certain geographical areas is much more complex than previously believed. J. Med. Virol. 65:730,735, 2001. © 2001 Wiley-Liss, Inc. [source]

Screening of Water Yam (Dioscorea alata L.) Genotypes for Reactions to Viruses in Nigeria

JOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2006
B. O. Odu
Abstract Studies were made to identify sources of resistance to yam viruses in Dioscorea alata. Forty genotypes of D. alata were evaluated in both the field and in the screenhouse for reactions to the yam viruses: Yam mosaic virus (YMV), genus Potyvirus; Dioscorea alata virus (DAV), genus Potyvirus; Cucumber mosaic virus (CMV), genus Cucumovirus; and Dioscorea alata bacilliform virus (DaBV), genus Badnavirus. The D. alata genotypes were planted in the field and subsequently scored for virus symptom severity. All the genotypes were also planted in an insect-proofed screenhouse, and challenged mechanically and by vectors for susceptibility to each of the viruses. Analysis of variance (anova) of the symptom severity scores showed that the genotypes responded differently (P < 0.01) to virus disease in the field. Field evaluation also showed that TDa 291 (a landrace genotype from Puerto Rico), TDa 87/01091, TDa 96-4, TDa 95-163 and TDa 289 from Nigeria, and TDa 95-25 (a landrace genotype from Ghana), had a low virus disease symptom rating. Overall screening results showed that two D. alata genotypes (TDa 289 and TDa 291) are good sources of resistance to YMV, DAV and CMV, and that they are tolerant to DaBV. [source]

Viruses Associated with Cassava Mosaic Disease in Senegal and Guinea Conakry

JOURNAL OF PHYTOPATHOLOGY, Issue 2 2004
G. Okao-Okuja
Abstract A survey in Senegal and Guinea Conakry established the presence and incidence of cassava mosaic virus disease (CMD) in both countries. CMD occurred in all the fields surveyed, although its incidence was higher in Senegal (83%) than in Guinea (64%). Populations of the whitefly vector, Bemisia tabaci, were low in both countries averaging 1.7 adults per shoot in Guinea and 3.2 in Senegal. Most infections were attributed to the use of infected cuttings, 86 and 83% in Senegal and Guinea, respectively, and there was no evidence of rapid current-season, whitefly-borne infection at any of the sampled locations. Disease severity was generally low in the two countries and averaged 2.5 in Guinea and 2.3 in Senegal. No plants with unusually severe CMD symptoms characteristic of the CMD pandemic in East and Central Africa were observed. Restriction fragment length polymorphism (RFLP)-based diagnostics revealed that African cassava mosaic virus (ACMV) is exclusively associated with CMD in both the countries. Neither East African cassava mosaic virus (EACMV), nor the recombinant Uganda variant (EACMV-UG2) was detected in any sample. These survey data indicate that CMD could be effectively controlled in both countries by phytosanitation, involving the use of CMD-free planting material and the removal of diseased plants. [source]

Surveys for Beet Necrotic Yellow Vein Virus (the Cause of Rhizomania), other Viruses, and Soil-borne Fungi Infecting Sugar Beet in Syria

JOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2002
A. M. Mouhanna
Abstract Production of sugar beet, the most important source of sugar in Syria, has suffered from many problems in the past, especially from diseases. No previous surveys have been made in Syria for viral diseases and soil-borne fungi of sugar beet. In 1998, samples were collected from plants showing symptoms of virus infection (yellowing, wilting, necrosis and mosaic). Root samples (341) were collected from crops of autumn-sown seed from 115 localities in seven provinces, 173 root samples from spring-sown crops and 39 leaf samples were collected during both seasons. The root samples were tested for the presence of viruses by double antibody sandwich-enzyme-linked immunosorbent assay (ELISA) and triple antibody sandwich-ELISA, and for soil-borne fungi by red plate (Rose Bengal) dishes. We have shown for the first time the presence of Beet necrotic yellow vein virus, Beet soil-borne virus, Beet yellows virus and Beet mild yellowing virus in Syrian sugar beet fields in which Rhizoctonia sp. and Fusarium sp. were also widely distributed. [source]