In this task, you're given a paragraph from the research paper and your task is to generate a suitable title for the research paper based on the given paper. Under 100 words is a good title length.

We performed experiments to determine the effect of PKR activation on respiratory syncytial virus (RSV) replication. We first determined that RSV infection activates PKR which induces the phosphorylation of eIF2α, resulting in the formation of host stress granules. We used RNA interference to decrease endogenous PKR levels. RSV replication was not altered in cells deficient for PKR expression. However, RSV-mediated stress granule formation was significantly reduced in PKR-knockdown cells. As an alternative method to block PKR activation, we used treatment with the kinase inhibitor 2-aminopurine (2-AP). We observed that 2-AP treatment significantly reduced viral replication. We also treated PKR-knockdown cells with 2-AP and inoculated with RSV. Under these conditions, 2-AP treatment diminished viral replication in the absence of PKR expression. These results suggest that PKR activation has a minimal effect on RSV replication and that the antiviral effect of 2-AP during RSV infection likely occurs via a PKR-independent mechanism.
Activation of protein kinase R is required for induction of stress granules by respiratory syncytial virus but dispensable for viral replication

Background: Human adenoviruses are common causes of community-acquired respiratory tract and enteric infections. Severe disseminated infections with high mortality rates may be seen in immunocompromised individuals. An accurate and cost-effective quantitative assay is essential not only for laboratory diagnosis of adenoviral infections, but also for monitoring of response to antiviral treatment. The diagnostic performance of an in-house quantitative polymerase chain reaction assay was compared to a commercial system. Methods: The analytical sensitivity, specificity, linearity, precision and accuracy of an in-house adenovirus quantitative polymerase chain reaction assay were evaluated against the RealStar® Adenovirus PCR Kit (Altona Diagnostics GmbH, Hamburg, Germany), using 122 clinical specimens and 18 proficiency testing samples. Results: Linear regression analysis of the quantitative results by the in-house assay showed the dynamic range from 2.60 to 9 log 10 (plasma) and 2.94 to 9 log 10 (viral transport medium) copies/mL, with the coefficient of determination (R 2 ) of 0.996 and 0.998, respectively. A dilution series demonstrated the limits of detection and lower limits of quantification for plasma were 2.06 log 10 and 2.60 log 10 copies/mL and those for viral transport medium were 2.31 log 10 and 2.94 log 10 copies/mL respectively. The precision of the in-house assay was highly reproducible among runs with coefficients of variance ranging from 0.07 to 3.21% for plasma and 0.17% to 2.11% for viral transport medium. A comparison of 52 matched samples showed an excellent correlation between the quantitative viral loads measured by the in-house assay and the RealStar® Adenovirus PCR Kit (R 2 = 0.984), with an average bias of − 0.16 log 10 copies/mL. Conclusions: The in-house adenovirus assay is a sensitive and reliable assay with lower cost for the detection and quantification of adenoviral DNA when compared to the RealStar® Adenovirus PCR Kit.
Comparative evaluation of a laboratory- developed real-time PCR assay and RealStar® Adenovirus PCR Kit for quantitative detection of human adenovirus

The function of Semliki Forest Virus nsP2 protease was investigated by site-directed mutagenesis. Mutations were introduced in its protease domain, Pro39, and the mutated proteins were expressed in Escherichia coli, purified and their activity in vitro was compared to that of the wild type Pro39. Mutations M781T, A662T and G577R, found in temperaturesensitive virus strains, rendered the enzyme temperature-sensitive in vitro as well. Five conserved residues were required for the proteolytic activity of Pro39. Changes affecting Cys 478 , His 548 , and Trp 549 resulted in complete inactivation of the enzyme, whereas the replacements N600D and N605D significantly impaired its activity. The importance of Trp 549 for the proteolytic cleavage specificity is discussed and a new structural motif involved in substrate recognition by cysteine proteases is proposed.

Characterization of the cysteine protease domain of Semliki Forest virus replicase protein nsP2 by in vitro mutagenesis