In contrast, oligomers and protofibrils not only remained intact but were capable of self-replication using native monomers as the substrate. Kinetic data further suggested that this prion-like growth mode of oligomers/protofibrils involved two distinct activities operating orthogonal from each other: autocatalytic self-replication of oligomers from native monomers and nucleated polymerization of oligomers into protofibrils.
The environmental changes to stability and templating competence of these different amyloid species in different environments are likely to be important for understanding the molecular mechanisms underlying both pathogenic and functional amyloid self-assembly.”
“Recombinant virus-like particles (VLPs) represent a safe and effective Small molecule library screening vaccine strategy. We previously described a stable LDN-193189 nmr transgenic plant system for inexpensive production and oral delivery of VLP vaccines. However, the relatively low-level antigen accumulation and long-time frame to produce transgenic plants are the two major roadblocks in the practical. development of, plant-based VLP production. In this article, we describe the optimization of geminivirus-derived DNA replicon vectors for rapid, high-yield plant-based production of VLPs. Co-delivery of bean yellow dwarf virus (BeYDV)-derived vector and Rep/RepA-supplying vector by agroinfiltration of Nicotiana benthamiana leaves, resulted
in efficient replicon amplification and robust protein production within 5 days. Co-expression of the P19 protein of tomato bush stunt virus, a gene silencing inhibitor, further Barasertib Cell Cycle inhibitor enhanced VLP accumulation by stabilizing the mRNA. With this system, hepatitis B core antigen (HBc) and Norwalk virus capsid protein
(NVCP) were produced at 0.86 and 0.34 mg/g leaf fresh weight, respectively. Sedimentation analysis and electron microscopy of transiently expressed antigens verified the efficient assembly of VLPs. Furthermore, a single replicon vector containing a built-in Rep/RepA cassette without P19 drove protein expression at similar levels as the three-component system. These results demonstrate the advantages of fast and high-level production of VLP-based vaccines using the BeYDV-derived DNA replicon system for transient expression in plants. Biotechnol. Bioeng. 2009;103: 706-714. (c) 2009 Wiley Periodicals, Inc.”
“The prevalence of adaptive evolution relative to genetic drift is a central problem in molecular evolution. Methods to estimate the fraction of adaptive nucleotide substitutions (alpha) have been developed, based on the McDonald-Kreitman test, that contrast polymorphism and divergence between selectively and neutrally evolving sites. However, these methods are expected to give downwardly biased estimates of alpha if there are slightly deleterious mutations, because these inflate polymorphism relative to divergence.