Making of Viral Replication Organelles by Remodeling Interior Membranes

Positive-stranded RNA (+RNA) viruses exploit host cell machinery by subverting host proteins and membranes and altering cellular pathways during infection. To achieve robust replication, some +RNA viruses, such as poliovirus (PV), build special intracellular compartments, called viral replication organelles. A recent work from the Altan-Bonnett laboratory [1] gave new insights into the formation of poliovirus replication organelles, which are unique subcellular structures containing many individual replication complexes as a result of dynamic cellular membrane remodeling

Tombusvirus-Yeast Interactions Identify Conserved Cell-Intrinsic Viral Restriction Factors

To combat viral infections, plants possess innate and adaptive immune pathways, such as RNA silencing, R gene and recessive gene-mediated resistance mechanisms. However, it is likely that additional cell-intrinsic restriction factors (CIRF) are also involved in limiting plant virus replication. This review discusses novel CIRFs with antiviral functions, many of them RNA-binding proteins or affecting the RNA binding activities of viral replication proteins. The CIRFs against tombusviruses have been identified in yeast (Saccharomyces cerevisiae), which is developed as an advanced model organism. Grouping of the identified CIRFs based on their known cellular functions and subcellular localization in yeast reveals that TBSV replication is limited by a wide variety of host gene functions. Yeast proteins with the highest connectivity in the network map include the well-characterized Xrn1p 5\u27-3\u27 exoribonuclease, Act1p actin protein and Cse4p centromere protein. The protein network map also reveals an important interplay between the pro-viral Hsp70 cellular chaperone and the antiviral co-chaperones, and possibly key roles for the ribosomal or ribosome-associated factors. We discuss the antiviral functions of selected CIRFs, such as the RNA binding nucleolin, ribonucleases, WW-domain proteins, single- and multi-domain cyclophilins, TPR-domain co-chaperones and cellular ion pumps. These restriction factors frequently target the RNA-binding region in the viral replication proteins, thus interfering with the recruitment of the viral RNA for replication and the assembly of the membrane-bound viral replicase. Although many of the characterized CIRFs act directly against TBSV, we propose that the TPR-domain co-chaperones function as guardians of the cellular Hsp70 chaperone system, which is subverted efficiently by TBSV for viral replicase assembly in the absence of the TPR-domain co-chaperones

Frog Prince transposon-based RNAi vectors mediate efficient gene knockdown in human cells

We have developed a stable RNA interference (RNAi) delivery system that is based on the Frog Prince transposable element. This plasmid-based vector system combines the gene silencing capabilities of H1 polymerase III promoter-driven short hairpin RNAs (shRNA) with the advantages of stable and efficient genomic integration of the shRNA cassette mediated by transposition. We show that the Frog Prince-based shRNA expressing system can efficiently knock down the expression of both exogenous as well as endogenous genes in human cells. Furthermore, we use the Frog Prince-based system to study the effect of knockdown of the DNA repair factor Ku70 on transposition of the Sleeping Beauty transposon. Transposon-mediated genomic integration ensures that the shRNA expression cassette and a selectable marker gene within the transposon remain intact and physically linked. We demonstrate that a major advantage of our vector system over plasmid-based shRNA delivery is both its enhanced frequency of intact genomic integration as well as higher target suppression in transgenic human cells. Due to its simplicity and effectiveness, transposon-based RNAi is an emerging tool to facilitate analysis of gene function through the establishment of stable loss-of-function cell lines

Recovery of surface-dwelling assemblages (Coleoptera: Carabidae, Staphylinidae) during clear-cut originated reforestation with native tree species

Background and purpose: Timber-oriented forest management has an important impact on biodiversity in forest ecosystems. Recovery dynamics of two groups of beetles (Coleoptera: Carabidae, Staphylinidae) were studied after reforestation with native English oak (Quercus robur). We expected that reforestation with heavy site preparation causes a shift in the diversity of surface-dwelling beetles in early phases of reforestation. Moreover, we tested the habitat specialist hypothesis, assuming that diversity of forest specialist species will be lower in early phases with open canopy than later phases of reforestation after the canopy closure.Materials and methods: We compared litter sifter samples among mature (130-year-old) oak forest, and recently established (5-year-old), young (15-year-old), middle-aged (45-year-old) reforestations.Results: Our results showed that diversity of ground beetles was the highest in the recently established reforestation, while it was the lowest in the mature oak forest. Contrarily, diversity of rove beetles was the lowest in recently established reforestation and it was the highest in the mature oak forest. In agreement with the habitat specialist hypothesis, the diversity of forest specialists of both taxa was lower in the recently established reforestation than in the young and middle-aged reforestations as well as mature forest.Discussion: Our results suggested that clear-cutting of mature forest, site preparation before reforestation and cultivation by light tilling in early phases of reforestation have detrimental effects on forest specialist rove beetles and ground beetles. However, reforestation with native species could be a feasible management method in pannonic mesophile sand steppe, because forest specialist species can recover after the canopy closure.</p

Assembly-hub Function of ER-Localized SNARE Proteins in Biogenesis of Tombusvirus Replication Compartment

Positive-strand RNA viruses assemble numerous membrane-bound viral replicase complexes within large replication compartments to support their replication in infected cells. Yet the detailed mechanism of how given subcellular compartments are subverted by viruses is incompletely understood. Although, Tomato bushy stunt virus (TBSV) uses peroxisomal membranes for replication, in this paper, we show evidence that the ER-resident SNARE (soluble NSF attachment protein receptor) proteins play critical roles in the formation of active replicase complexes in yeast model host and in plants. Depletion of the syntaxin 18-like Ufe1 and Use1, which are components of the ER SNARE complex in the ERAS (ER arrival site) subdomain, in yeast resulted in greatly reduced tombusvirus accumulation. Over-expression of a dominant-negative mutant of either the yeast Ufe1 or the orthologous plant Syp81 syntaxin greatly interferes with tombusvirus replication in yeast and plants, thus further supporting the role of this host protein in tombusvirus replication. Moreover, tombusvirus RNA replication was low in cell-free extracts from yeast with repressed Ufe1 or Use1 expression. We also present evidence for the mislocalization of the tombusviral p33 replication protein to the ER membrane in Ufe1p-depleted yeast cells. The viral p33 replication protein interacts with both Ufe1p and Use1p and co-opts them into the TBSV replication compartment in yeast and plant cells. The co-opted Ufe1 affects the virus-driven membrane contact site formation, sterol-enrichment at replication sites, recruitment of several pro-viral host factors and subversion of the Rab5-positive PE-rich endosomes needed for robust TBSV replication. In summary, we demonstrate a critical role for Ufe1 and Use1 SNARE proteins in TBSV replication and propose that the pro-viral functions of Ufe1 and Use1 are to serve as assembly hubs for the formation of the extensive TBSV replication compartments in cells. Altogether, these findings point clearly at the ERAS subdomain of ER as a critical site for the biogenesis of the TBSV replication compartment

ZDRAVLJE 2020 – Postizanje zdravlja i razvoja u današnjoj Europi

Zdravlje i blagostanje su ciljevi svakog čovjeka. Oni se danas smatraju kao najvažnija ljudska prava, glavne komponente pravičnog humanog, ekonomskog i društvenog razvoja, kao i resurs za svakodnevni život. Sve je više prisutno uvjerenje da su ovi ciljevi esencijalno važni za humani razvoj i sigurnost. Na zdravlje se više ne gleda samo kao na stavku u potrošnji za koju treba osigurati sredstva već kao na vrijednost koju treba njegovati i pravično unapređivati. Na zdravlje se gleda i kao na jedan pozitivni koncept, u kojem se naglašavaju društveni i individualni resursi, kao i fizički kapacitet

SĂNĂTATEA 2020 – SĂNĂTATE ŞI DEZVOLTARE ÎN EUROPA DE AZI

An interesting insight on the Health 2020 European Health Strategy is revealed in the next content proposed for the journal section dedicated to personalities of health management, given that the authors of this paper have a huge experience in health management at European level and are deeply involved in elaborating and implementing the new European Health Strategy.Health 2020 is the new European health policy framework. It aims to support action across government and society to: “significantly improve the health and well-being of populations, reduce health inequalities, strengthen public health and ensure people-centred health systems that are universal, equitable, sustainable and of high quality”.O perspectivă interesantă asupra Strategiei europene de sănătate &ldquo;Sănătatea 2020&rdquo; este dezvăluită &icirc;n conținutul ce urmează, pe care vi-l propunem pentru secțiunea dedicată personalităților din managementul sanitar, av&acirc;nd &icirc;n vedere că autorii acestei lucrări au o experiență foarte mare &icirc;n managementul sanitar la nivel european și sunt profund implicați &icirc;n elaborarea și punerea &icirc;n aplicare a noii strategii europene din domeniul sănătății. &rdquo;Sănătatea 2020&rdquo; este noul cadru de politici de sănătate europene. Acesta are ca scop sprijinirea acțiunilor intreprinse de către guverne și societăți &icirc;n vederea: "&icirc;mbunătățirii &icirc;n mod semnificativ a sănătății și bunăstării populației, reducerii inegalităților &icirc;n domeniul sănătății, &icirc;ntăririi sănătății publice și asigurării unor &icirc;ngrijiri de sănătate centrate pe cetățeni, care sunt universale, echitabile, durabile și de &icirc;naltă calitate"

Filling the complexity gaps for colouring planar and bounded degree graphs

We consider a natural restriction of the List Colouring problem, k-Regular List Colouring, which corresponds to the List Colouring problem where every list has size exactly k. We give a complete classification of the complexity of k-Regular List Colouring restricted to planar graphs, planar bipartite graphs, planar triangle-free graphs and to planar graphs with no 4-cycles and no 5-cycles. We also give a complete classification of the complexity of this problem and a number of related colouring problems for graphs with bounded maximum degree