Deletion series in the P1 protein of the Sweet potato mild mottle virus identifies the shortest fully functional RNA silencing suppressor domain

RNA silencing is a part of the plant innate immune system that could effectively cope with intruders, like viruses. However, viruses evolved proteins that can suppress RNA silencing thus supporting virus spreading in the host. To counteract RNA silencing, suppressor proteins attack different players of RNA silencing pathway. The P1 protein of the Sweet potato mild mottle virus binds and inactivates small RNA loaded RISC complexes. Using a deletion series in the P1 protein we aimed to identify the possible smallest working version of P1. Our results revealed that the minimal RNA silencing suppressor domain of P1 is as small as 210 amino acids in size

A viral suppressor of RNA silencing inhibits ARGONAUTE 1 function by precluding target RNA binding to pre-assembled RISC

In most eukaryotes, RNA silencing is an adaptive immune system regulating key biological processes including antiviral defense. To evade this response, viruses of plants, worms and insects have evolved viral suppressors of RNA silencing proteins (VSRs). Various VSRs, such as P1 from Sweet potato mild mottle virus (SPMMV), inhibit the activity of RNA-induced silencing complexes (RISCs) including an ARGONAUTE (AGO) protein loaded with a small RNA. However, the specific mechanisms explaining this class of inhibition are unknown. Here, we show that SPMMV P1 interacts with AGO1 and AGO2 from Arabidopsis thaliana, but solely interferes with AGO1 function. Moreover, a mutational analysis of a newly identified zinc finger domain in P1 revealed that this domain could represent an effector domain as it is required for P1 suppressor activity but not for AGO1 binding. Finally, a comparative analysis of the target RNA binding capacity of AGO1 in the presence of wild-type or suppressor-defective P1 forms revealed that P1 blocks target RNA binding to AGO1. Our results describe the negative regulation of RISC, the small RNA containing molecular machine

Az RNS silencing mechanizmusának vizsgálata állati és növényi modelleken = Mechanism of RNS silencing in animal and plant model organism

A Cymbidium ringspot vírussal fertőzött növényekből származó kis RNS-ek analízise során azt találtuk, hogy a virális kis RNS-ek a genom kitüntetett helyeiről keletkeznek és a a virális kis RNS-ek 80%-a a pozitív, 20%-a a negatív szálról képződik. Ez az arány megegyezik a genomi RNS-ek szálarányával. Eredményeinkből az következik, hogy a virális kis RNS-ek nem a virus ds replikatív intermedierjéről, hanem az egyszálú genomi RNS-ek másodlagos szerkezettel rendelkező régióiról keletkeznek. Az RNS silencing szupresszorokkal végzett munkánk alapján megállapítottuk, hogy a vizsgált virális szupresszorok mind a növényi, mind az állati rendszerekben a kis RNS-ek megkötésével gátolják a RISC komplexek, ezáltal a si- és miRNS indukálta RNS silencing kialakulását. Mivel az általunk vizsgált vírusok taxonómiailag különböző családokba sorolhatók, ezért azt a következtetés is levonhatjuk, hogy a siRNS kötésen alapuló RNS silencing gátlás egy széleskörűen elterjedt RNS silencing szupressziós stratégia. Jól jellemzett kis RNS kötő RNS silencing szupresszorral rendelkező vírusok hatását vizsgáltuk a a kis RNS-ek 3 vessző vég metilációjára. Eredményeink azt mutatják, hogy a TEV HCPro hatékonyan, míg a CIRV p19 kevéssé gátolja meg a virális siRNS-ek és bizonyos endogén miRNS-ek 3 vessző végének metilációját. Sejtfrakcionálásos eredményeink alapján feltételezhetjük, hogy a kis RNS-ek metilációja nemcsak a sejtmagban, hanem a citoplazmában is bekövetkezhet. | A survey of virus-specific siRNAs characterized by a sequence analysis of siRNAs from plants infected with Cymbidium ringspot virus showed that viral siRNA sequences have a nonrandom distribution along the length of the viral genome, suggesting that viral siRNAs derived from highly structured regions of the single stranded viral genome, rather than the ds replicative intermedier. Analyzing several silencing suppressors representing different families of viruses showed that each inhibit the intermediate step of RNA silencing via binding to siRNAs, although the molecular features required for duplex siRNA binding differ among these proteins. None of the suppressors affected the activity of preassembled RISC complexes. In contrast, each suppressor uniformly inhibited the siRNA-initiated RISC assembly pathway by preventing RNA silencing initiator complex formation. We investigated the 3' modification of silencing-related small RNAs in plants infected with viruses expressing small RNA silencing suppressors. We found that CIRV had only a slight effect on viral siRNA 3' modification, but TEV significantly inhibited the 3' modification of si/miRNAs. This suggests that the 3' modification of viral siRNAs occurs in the cytoplasm, though miRNA 3' modification likely takes place in the nucleus as well

Changes in resistance pattern of ESKAPE pathogens between 2010 and 2020 in the clinical center of University of Szeged, Hungary

The acronym ESKAPE stands for six antibiotic-resistant bacterial pathogens namely, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp. Monitoring their resistance is an important task for clinical microbiology laboratories. Our aim was to analyze the resistance patterns of these bacteria over ten years in clinical samples of our department. We examined the sample types from which these pathogens were most frequently isolated. The incidence of tests with resistant results for each pathogen in aggregate and the most important subgroups of each was also analyzed. We have also intended to predict the local priorities amongst these pathogens. The results of 1,268,126 antibiotic susceptibility tests performed on a total of 70,099 isolates over this period were examined. Most strains were derived from urine, blood culture, trachea, vagina, wounds, and abscesses. Prevalence of ESKAPE bacteria increased between 2011 and 2020 however, the steepest intensifications were seen in the cases of K. pneumoniae and P. aeruginosa. The number of antibiotic susceptibility tests with resistant results has also increased over the decade but the most notable increase was detected in E. faecium and A. baumannii. Based on the calculation of antimicrobial resistance index for each pathogen, the most serious challenges for us at present are A. baumannii, P. aeruginosa, and E. faecium and their multi-resistant forms. The theoretical prediction of proportion of resistant tests between 2020 and 2030 in our care area draws attention to a worrying trend in the cases of vancomycin-resistant E. faecium and carbapenem-resistant A. baumannii strains

Quality of care in inflammatory bowel diseases: What is the best way to better outcomes?

Inflammatory bowel disease (IBD) is a lifelong, progressive disease that has disabling impacts on patient's lives. Given the complex nature of the diagnosis of IBD and its management there is consequently a large economic burden seen across all health care systems. Quality indicators (QI) have been created to assess the different facades of disease management including structure, process and outcome components. Their development serves to provide a means to target and measure quality of care (QoC). Multiple different QI sets have been published in IBD, but all serve the same purpose of trying to achieve a standard of care that can be attained on a national and international level, since there is still a major variation in clinical practice. There have been many recent innovative developments that aim to improve QoC in IBD including telemedicine, home biomarker assessment and rapid access clinics. These are some of the novel advancements that have been shown to have great potential at improving QoC, while offloading some of the burden that IBD can have vis-a-vis emergency room visits and hospital admissions. The aim of the current review is to summarize and discuss available QI sets and recent developments in IBD care including telemedicine, and to give insight into how the utilization of these tools could benefit the QoC of IBD patients. Additionally, a treating-to-target structure as well as evidence surrounding aggressive management directed at tighter disease control will be presented