scholarly journals Virus altered rice attractiveness to planthoppers is mediated by volatiles and related to virus titre and expression of defence and volatile-biosynthesis genes

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Guanghua Lu ◽  
Tong Zhang ◽  
Yuange He ◽  
Guohui Zhou
Keyword(s):  
Virus Titre

scholarly journals Encephalomyocarditis (EMC) virus-induced testicular lesion in BALB/c mice

1994 ◽  
Vol 28 (4) ◽  
pp. 330-334 ◽  
Author(s):  
M. Shigesato ◽  
K. Hirasawa ◽  
M. Takeda ◽  
K. Doi
Keyword(s):  
Virus Titre ◽  
Male Mice ◽  
Inflammatory Infiltration ◽  
Emc Virus ◽  
Testicular Lesions ◽  
Almost All ◽  
Germinal Cells ◽  
Old Mice

Characteristics of encephalomyocarditis (EMC) virus-induced testicular lesions were investigated in 4- and 8-week-old BALB/c male mice after intraperitoneal (i.p.) and intratesticular (left) (i.t.) inoculation of the D variant of EMC virus (EMC-D). Apart from variation in severity and incidence, the histopathological nature of the resultant testicular lesion was similar in all infected mice, and was characterized by degeneration and necrosis of germinal cells and spermatogonia with inflammatory infiltration. Almost all the inoculated left testes of the i.t. group developed marked lesions. In general, the virus titre in the testis and incidence of testicular lesions were higher in 4-week-old mice than in 8-week-old mice. In addition, testicular lesions developed earlier and with a higher incidence in the PBS-inoculated right testis of the i.t. group than in either testis of the i.p. group of the same age.

scholarly journals Duck hepatitis B virus: a model to assess efficacy of disinfectants against hepadnavirus infectivity

1991 ◽  
Vol 106 (3) ◽  
pp. 435-443 ◽  
Author(s):  
S. M. Murray ◽  
J. S. Freiman ◽  
K. Vickery ◽  
D. Lim ◽  
Y. E. Cossart ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Room Temperature ◽  
Virus Titre ◽  
Experimental Protocol ◽  
Duck Hepatitis B Virus ◽  
Duck Hepatitis ◽  
B Virus ◽  
Undiluted Serum ◽  
Sterile Filter

SUMMARYThe efficacy of three proprietary glutaraldehyde disinfectants and their component bases was assessed using the duck hepatitis B virus (DHBV) model. Inactivation of infectivity of undiluted serum containing 106·8ID50/ml DHBV was assessed after a mixture with an equal volume of disinfectant had stood at room temperature for 10 min. A dried spill of infectious serum was simulated using sterile filter paper disks, saturated with serum containing DHBV, dried and then exposed to test disinfectant for 10 min. Residual infectivity, and hence the reduction in virus titre, was determined by inoculation of dilutions of the treated samples into 1-day-old ducklings. A greater than 3 log10reduction in virus titre could be demonstrated for the disinfectants as well as for some of their component bases. Disinfectant activity varied according to the method of viral presentation but a reduction of exposure time from 10 to 2·5 min did not diminish activity. The experimental protocol permits a comparative and quantitative assessment of the efficacy of both established and new disinfectants.

scholarly journals Disease control and its selection for damaging plant virus strains in vegetatively propagated staple food crops; a theoretical assessment

2006 ◽  
Vol 274 (1606) ◽  
pp. 11-18 ◽  
Author(s):  
F van den Bosch ◽  
M.J Jeger ◽  
C.A Gilligan
Keyword(s):  
Disease Control ◽  
Plant Virus ◽  
Virus Titre ◽  
Viral Diseases ◽  
Food Crops ◽  
Control Methods ◽  
Staple Food ◽  
Risk Of Failure ◽  
Selection For ◽  
Virus Strains

Viral diseases are a key constraint in the production of staple food crops in lesser developed countries. New and improved disease control methods are developed and implemented without consideration of the selective pressure they impose on the virus. In this paper, we analyse the evolution of within-plant virus titre as a response to the implementation of a range of disease control methods. We show that the development of new and improved disease control methods for viral diseases of vegetatively propagated staple food crops ought to take the evolutionary responses of the virus into consideration. Not doing so leads to a risk of failure, which can result in considerable economic losses and increased poverty. Specifically in vitro propagation, diagnostics and breeding methods carry a risk of failure due to the selection for virus strains that build up a high within-plant virus titre. For vegetatively propagated crops, sanitation by roguing has a low risk of failure owing to its combination of selecting for low virus titre strains as well as increasing healthy crop density.

scholarly journals Arthropod transmission of rabbit fibromatosis (Shope)

1959 ◽  
Vol 57 (1) ◽  
pp. 1-30 ◽  
Author(s):  
Herbert T. Dalmat
Keyword(s):  
Aedes Aegypti ◽  
Culex Pipiens ◽  
Rhodnius Prolixus ◽  
Triatoma Infestans ◽  
Cimex Lectularius ◽  
Virus Titre ◽  
Virus Suspension ◽  
Anopheles Quadrimaculatus ◽  
Domestic Rabbits ◽  
Reduviid Bugs

The mosquitoes Aedes aegypti, A. triseriatus, Culex pipiens, C. quinquefasciatus, and Anopheles quadrimaculatus were all found to be efficient experimental vectors of Shope's virus-induced fibromas of cottontail rabbits, transmitting the virus during interrupted feedings as well as after long intervals from an infective meal. The reduviid bugs, Triatoma infestans, T. phyllosoma pallidipennis and Rhodnius prolixus, and the bedbug, Cimex lectularius, were also capable of transmitting fibroma by interrupted or delayed feeding.Evidence from various types of experiments indicated that arthropod transmission is mechanical, the virus being extremely stable in the insects. Some experiments did indicate the possibility of virus proliferation. Although mosquitoes did seem to serve as ‘flying pins’ when transmitting virus by interrupted feeding, they certainly were distinctive in that they maintained their ability to transmit for very long periods of time. To transmit fibromas, arthropods actually must draw virus up between the stylets of the mouthparts; mosquitoes were unable to transmit by feeding through skin moistened with a suspension of fibroma virus or by feeding subsequent to having their mouthparts painted with a virus suspension.While cottontail tumours at peak virus titres are always infective for suitable insects, the fibromas of adult domestic rabbits generally are not infective, even though the virus titre is equivalent. However, the tumours of suckling domestic rabbits do become infective for insects.

Newcastle disease vaccination: the maintenance of virus titre in header tank supplies

1973 ◽  
Vol 93 (18) ◽  
pp. 487-487 ◽  
Author(s):  
W. Allan ◽  
J. Papanikolaou
Keyword(s):  
Newcastle Disease ◽  
Virus Titre

Phosphorylation of hepatitis B virus core C-terminally truncated protein (Cp149) by PKC increases capsid assembly and stability

2008 ◽  
Vol 416 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Hang Kang ◽  
Jaehoon Yu ◽  
Guhung Jung
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Core Protein ◽  
Virus Titre ◽  
Capsid Assembly ◽  
Human Hepatoma Cells ◽  
Virus Core ◽  
C Terminus ◽  
B Virus

The HBV (hepatitis B virus) core is a phosphoprotein whose assembly, replication, encapsidation and localization are regulated by phosphorylation. It is known that PKC (protein kinase C) regulates pgRNA (pregenomic RNA) encapsidation by phosphorylation of the C-terminus of core, which is a component packaged into capsid. Neither the N-terminal residue phosphorylated by PKC nor the role of the C-terminal phosphorylation have been cleary defined. In the present study we found that HBV Cp149 (core protein C-terminally truncated at amino acid 149) expressed in Escherichia coli was phosphorylated by PKC at Ser106. PKC-mediated phosphorylation increased core affinity, as well as assembly and capsid stability. In vitro phosphorylation with core mutants (S26A, T70A, S106A and T114A) revealed that the Ser106 mutation inhibited phosphorylation of core by PKC. CD analysis also revealed that PKC-mediated phosphorylation stabilized the secondary structure of capsid. When either pCMV/FLAG-Cp149[WT (wild-type)] or pCMV/FLAG-S106A Cp149 was transfected into Huh7 human hepatoma cells, mutant capsid level was decreased by 2.06-fold with the S106A mutant when compared with WT, although the same level of total protein was expressed in both cases. In addition, when pUC1.2x and pUC1.2x/S106A were transfected, mutant virus titre was decreased 2.31-fold compared with WT virus titre. In conclusion, PKC-mediated phosphorylation increased capsid assembly, stability and structural stability.

scholarly journals More recent swine vesicular disease virus isolates retain binding to coxsackie–adenovirus receptor, but have lost the ability to bind human decay-accelerating factor (CD55)

2005 ◽  
Vol 86 (5) ◽  
pp. 1369-1377 ◽  
Author(s):  
Miguel A. Jimenez-Clavero ◽  
Estela Escribano-Romero ◽  
Victoria Ley ◽  
O. Brad Spiller
Keyword(s):  
Cell Line ◽  
Disease Virus ◽  
Hela Cells ◽  
Virus Titre ◽  
Decay Accelerating Factor ◽  
Coxsackie Adenovirus Receptor ◽  
Swine Vesicular Disease Virus ◽  
Virus Serotype ◽  
Adenovirus Receptor ◽  
Vesicular Disease

Swine vesicular disease virus (SVDV) evolved from coxsackie B virus serotype 5 (CVB5) in the recent past, crossing the species barrier from humans to pigs. Here, SVDV isolates from early and recent outbreaks have been compared for their capacity to utilize the progenitor virus receptors coxsackie–adenovirus receptor (CAR) and decay-accelerating factor (DAF; CD55). Virus titre of CVB5 and SVDV isolates It′66 and UK′72 on human HeLa cells was reduced by pre-incubation with either anti-DAF or anti-CAR antibodies; however, recent SVDV isolates R1072, R1120 and SPA′93 did not infect HeLa cells lytically. CVB5 and SVDV infection of the pig cell line IB-RS-2 was inhibited completely by anti-CAR antibodies for all isolates, and no reduction was observed following pre-incubation of cells with anti-pig DAF antibodies. Expression of human DAF in the pig cell line IB-RS-2 enhanced the virus titre of early SVDV isolates by 25-fold, but had no effect on recent SVDV isolate titre. Binding of radiolabelled CVB5 to IB-RS-2 cells was increased seven- to eightfold by expression of human DAF and binding of early SVDV isolates was increased 1·2–1·3-fold, whereas no increase in binding by recent SVDV isolates was mediated by human DAF expression. Addition of soluble hDAF-Fc inhibited CVB5, but not SVDV, infection of pig cells. Pre-incubation of all viruses with soluble hCAR-Fc blocked infection of IB-RS-2 pig cells completely; titration of the amount of soluble hCAR-Fc required to block infection revealed that early isolate UK′72 was the least susceptible to inhibition, and the most recent isolate, SPA′93, was the most susceptible.

Rotavirus survival in conventionally treated drinking water

1984 ◽  
Vol 30 (5) ◽  
pp. 653-656 ◽  
Author(s):  
S. A. Sattar ◽  
R. A. Raphael ◽  
V. S. Springthorpe
Keyword(s):  
Drinking Water ◽  
Treatment Plant ◽  
Free Chlorine ◽  
Virus Titre ◽  
Distilled Water ◽  
Virus Suspension ◽  
Term Survival ◽  
Tryptose Phosphate Broth ◽  
Treated Drinking Water

Samples of conventionally treated drinking water collected either as effluent (PE) at a treatment plant or out of a tap (TW) in our laboratory were seeded with simian rotavirus SA-11, which closely resembles rotavirus of human origin. The virus, grown in MA-104 cells, was suspended either in distilled water, Earle's balanced salt solution (EBSS), or tryptose phosphate broth (TPB), and added to the water samples to a final concentration of 5.7 × 103 plaque-forming units (PFU) per millilitre. After a contact time of 1 h at 22 °C, the samples were diluted and plaque assayed. There was no significant reduction in the virus titre in samples of TW (<0.05 mg/L free chlorine). The titre also remained almost the same in PE (0.75 mg/L free chlorine) when EBSS or TPB was used for virus suspension. There was, however, nearly a 1 log10 loss in the titre of the virus when it was suspended in distilled water before the contamination of PE. To study the long-term survival of the rotavirus in TW, the inoculated samples (5.0 × 104 PFU/mL) were held at either 4 or 20 °C in the dark and tested over a period of 64 days. At 20 °C it took 64 days to reduce the virus titre by 2 log10, whereas at 4 °C the virus titre dropped only 0.7 log10 during the same period. Rotaviruses could, therefore, survive well enough in conventionally treated drinking water to make it a possible vehicle for their transmission.

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