The Czech Trace in the History of Computer Technology

This publication traces the history of selected branches of computer science in the Czech lands and Czechoslovakia, spanning the period from the end of World War II to the 1990s. The book originated within the project of the Ministry of Culture NAKI II – A Century of Information: the World of Informatics and Electrical Engineering – The Computer World Inside Us, held in honor of the 70th anniversary of the modern establishment of the Faculty of Electrical Engineering of the Czech Technical University in Prague, and to mark the 40th anniversary of the death of the distinguished Czech scientist Antonín Svoboda. The publication is focused on three fundamental domains: the first one portrays the general development trends in computer technology (Reviewing Computer Technology Developments), the next section is devoted to the Czechoslovak/Czech (or rather Svoboda´s) computer school, showcasing the upswing of Czechoslovakia´s computer technology, associated primarily with the person of Antonín Svoboda, his colleagues and the achievements of the Research Institute of Mathematical Machines, while accentuating Czech/Czechoslovak contributions to the overal upsurge of information technology. The final part describes recent and contemporary advances in IT, particularly since the 1980s, featuring the Internet, the web and virtual reality. This publication provides an insightful invitation to reflect on the impressive progress of this particular branch, namely its giant technological leap made over the past 70 years

Disassociation of the SV40 Genome from Capsid Proteins Prior to Nuclear Entry

<p>Abstract</p> <p>Background</p> <p>Previously, we demonstrated that input SV40 particles undergo a partial disassembly in the endoplasmic reticulum, which exposes internal capsid proteins VP2 and VP3 to immunostaining. Then, in the cytoplasm, disassembly progresses further to also make the genomic DNA accessible to immune detection, as well as to detection by an ethynyl-2-deoxyuridine (EdU)-based chemical reaction. The cytoplasmic partially disassembled SV40 particles retain some of the SV40 capsid proteins, VP1, VP2, and VP3, in addition to the viral genome.</p> <p>Findings</p> <p>In the current study, we asked where in the cell the SV40 genome might disassociate from capsid components. We observed partially disassembled input SV40 particles around the nucleus and, beginning at 12 hours post-infection, 5-Bromo-2-deoxyuridine (BrdU)-labeled parental SV40 DNA in the nucleus, as detected using anti-BrdU antibodies. However, among the more than 1500 cells examined, we never detected input VP2/VP3 in the nucleus. Upon translocation of the BrdU-labeled SV40 genomes into nuclei, they were transcribed and, thus, are representative of productive infection.</p> <p>Conclusions</p> <p>Our findings imply that the SV40 genome disassociates from the capsid proteins before or at the point of entry into the nucleus, and then enters the nucleus devoid of VP2/3.</p

Magnetic Fractionation and Proteomic Dissection of Cellular Organelles Occupied by the Late Replication Complexes of Semliki Forest Virus

Alphavirus replicase complexes are initially formed at the plasma membrane and are subsequently internalized by endocytosis. During the late stages of infection, viral replication organelles are represented by large cytopathic vacuoles, where replicase complexes bind to membranes of endolysosomal origin. In addition to viral components, these organelles harbor an unknown number of host proteins. In this study, a fraction of modified lysosomes carrying functionally intact replicase complexes was obtained by feeding Semliki Forest virus (SFV)-infected HeLa cells with dextran-covered magnetic nanoparticles and later magnetically isolating the nanoparticle-containing lysosomes. Stable isotope labeling with amino acids in cell culture combined with quantitative proteomics was used to reveal 78 distinct cellular proteins that were at least 2.5-fold more abundant in replicase complex-carrying vesicles than in vesicles obtained from noninfected cells. These host components included the RNA-binding proteins PCBP1, hnRNP M, hnRNP C, and hnRNP K, which were shown to colocalize with the viral replicase. Silencing of hnRNP M and hnRNP C expression enhanced the replication of SFV, Chikungunya virus (CHIKV), and Sindbis virus (SINV). PCBP1 silencing decreased SFV-mediated protein synthesis, whereas hnRNP K silencing increased this synthesis. Notably, the effect of hnRNP K silencing on CHIKV- and SINV-mediated protein synthesis was opposite to that observed for SFV. This study provides a new approach for analyzing the proteome of the virus replication organelle of positive-strand RNA viruses and helps to elucidate how host RNA-binding proteins exert important but diverse functions during positive-strand RNA viral infection