Digitalization of Higher Education in 2021 – Challenges for University Students In Russia

Digital educational platforms emerged as an anticipated technological response to the need for the modernization of higher education. The digitalization of education was promoted at the state level as a strategy and an instrument to improve the quality and competitiveness of education. In 2020, the coronavirus pandemic accelerated the transition from the classroom to online-only, revealing the lack of purposeful online teaching methods, and insufficient digital competence among teachers. The authors analyzed publications by foreign and Russian researchers to highlight the common problems of higher education digitalization, including datafication, limited capabilities of digital educational platforms, and the changing role of the teachers in e-learning. The article focuses on students’ attitudes towards online education, and their voluntary or unwilling involvement in the digital educational environment, considering synchronous, asynchronous, and blended forms of learning before and during the pandemic. The achieved results suggest that such factors as the novelty and accessibility of online courses at Western universities initially served as a factor of attraction the students, inviting them to diversify their studies in their own creative way. However, increased stress and workload, various technical problems, tough teachers’ control on the one hand, and poor feedback, on the other, weakened the popularity of the digital educational environment. When asked to compare the pros and cons of online education, most students spoke in favour of maintaining the blended education format, as it allows for reducing the workload and – to some extent – enables the students to take control of their education trajectories. This work is intended for educators and researchers interested in the challenges caused by integrating digital technologies into traditional forms of education

Fragments of the nonlytic proline-rich antimicrobial peptide Bac5 kill Escherichia coli cells by inhibiting protein synthesis

Unlike most antimicrobial peptides (AMPs), the main mode of action of the subclass of proline-rich antimicrobial peptides (PrAMPs) is not based on disruption of the bacterial membrane. Instead, PrAMPs exploit the inner membrane transporters SbmA and YjiL/MdtM to pass through the bacterial membrane and enter the cytosol of specific Gram-negative bacteria, where they exert an inhibitory effect on protein synthesis. Despite sharing a high proline and arginine content with other characterized PrAMPs, the PrAMP Bac5 has a low sequence identity with them. Here we investigated the mode of action of three N-terminal Bac5 fragments, Bac5(1-15), Bac5(1-25), and Bac5(1-31). We show that Bac5(1-25) and Bac5(1-31) retained excellent antimicrobial activity toward Escherichia coli and low toxicity toward eukaryotic cells, whereas Bac5(1-15) was inactive. Bac5(1-25) and Bac5(1-31) inhibited bacterial protein synthesis in vitro and in vivo. Competition assays suggested that the binding site of Bac5 is within the ribosomal tunnel, where it prevents the transition from the initiation to the elongation phase of translation, as reported for other PrAMPs, such as the bovine PrAMP Bac7. Surprisingly, unlike Bac7, Bac5(1-25) exhibited speciesspecific inhibition, being an excellent inhibitor of protein synthesis on E. coli ribosomes but a poor inhibitor on Thermus thermophilus ribosomes. This indicates that while Bac5 most likely has an overlapping binding site with Bac7, the mode of interaction is distinct, suggesting that Bac5 fragments may be interesting alternative lead compounds for the development of new antimicrobial agents

A Functional Histidine-Tagged Replication Initiator Protein: Implications for the Study of Single-Stranded DNA Virus Replication In Planta

Replication initiation of nanoviruses, plant viruses with a multipartite circular single-stranded DNA genome, is triggered by the master Rep (M-Rep) protein. To enable the study of interactions between M-Rep and viral or host factors involved in replication, we designed oligohistidine-tagged variants of the nanovirus Faba bean necrotic yellows virus (FBNYV) M-Rep protein that allow affinity purification of enzymatically active M-Rep from plant tissue. The tagged M-Rep protein was able to initiate replication of its cognate and other FBNYV DNAs in Nicotiana benthamiana leaf disks and plants. The replicon encoding the tagged M-Rep protein multiplied and moved systemically in FBNYV-infected Vicia faba plants and was transmitted by the aphid vector of the virus. Using the tagged M-Rep protein, we demonstrated the in planta interaction between wild-type M-Rep and its tagged counterpart. Such a tagged and fully functional replication initiator protein will have bearings on the isolation of protein complexes from plants

Bradyrhizobium BclA is a peptide transporter required for bacterial differentiation in symbiosis with Aeschynomene legumes.

Nodules of legume plants are highly integrated symbiotic systems shaped by millions of years of evolution. They harbor nitrogen fixing rhizobium bacteria called bacteroids. Several legume species produce peptides called NCRs in the symbiotic nodule cells which house the bacteroids. NCRs are related to antimicrobial peptides of innate immunity. They induce the endosymbionts into a differentiated, enlarged and polyploid state. The bacterial symbionts on their side evolved functions for the response to the NCR peptides. Here we identified the bclA gene of Bradyrhizobium strains ORS278 and ORS285 which is required for the formation of differentiated and functional bacteroids in the nodules of the NCR-producing Aeschynomene legumes. The BclA ABC transporter promotes the import of NCR peptides and provides protection against the antimicrobial activity of these peptides. Moreover, BclA can complement the role of the related BacA transporter of Sinorhizobium meliloti which has a similar symbiotic function in the interaction with Medicago legumes

Twenty years of evolution and diversification of digitaria streak virus in Digitaria setigera

International audienceWithin the family Geminiviridae, the emergence of new species results from their high mutation and recombination rates. In this study, we report the variability and evolution of digitaria streak virus (DSV), a mastrevirus isolated in 1986 from the grass Digitaria setigera in an island of the Vanuatu archipelago. Viral DNA of DSV samples was amplified from D. setigera specimens, derived from the naturally infected original plant, which were propagated in different laboratories in France and Italy for more than 20 years. From the consensus sequences, the nucleotide substitution rate was estimated for the period between a sample and the original sequence published in 1987, as well as for the period between samples. In addition, the intra-host genetic complexity and diversity of 8 DSV populations with a total of 165 sequenced haplotypes was characterized. The evolutionary rate of DSV was estimated to be between 1.13 × 10 −4 and 9.87 × 10 −4 substitutions/site/year, within the ranges observed in other single-stranded DNA viruses and RNA viruses. Bioinformatic analyses revealed high variability and heterogeneity in DSV populations, which confirmed that mutant spectra are continuously generated and are organized as quasispecies. The analysis of polymorphisms revealed nucleotide substitution biases in viral genomes towards deamination and oxidation of single-stranded DNA. The differences in variability in each of the genomic regions reflected a dynamic and modular evolution in the mutant spectra that was not reflected in the consensus sequences. Strikingly, the most variable region of the DSV genome, encoding the movement protein, showed rapid fixation of the mutations in the consensus sequence and a concomitant dN/dS ratio of 6.130, which suggests strong positive selection in this region. Phylogenetic analyses revealed a possible divergence in three genetic lineages from the original Vanuatu DSV isolate

Cell Cycle and Terminal Differentiation in Sinorhizobium meliloti

International audienceSinorhizobium meliloti of the Alphaproteobacteria class has a fascinating spectrum of lifestyles, thriving as a free-living soil saprophyte, as an endophyte and as a nitrogen-fixing legume symbiont. In symbiosis, it undergoes a striking cellular differentiation process, which is controlled by the host plant through the activity of NCR peptides. NCRs interfere with the cell cycle of S. meliloti and transform the regular cycle consisting of strict successions of single DNA replication followed by cell division into an endoreduplication cycle of multiple genome duplications without divisions. This cellular differentiation results in giant and polyploid symbiotic bacterial cells that fix atmospheric nitrogen. Here we discuss the regulation of the free-living cell cycle in S. meliloti and present the hypothesis that the master regulator CtrA is the ultimate target of the NCR peptides, provoking the cell cycle switch in symbiosis

Complete and circularized genome sequences of five nitrogen-fixing Bradyrhizobium sp. strains isolated from root nodules of peanut, Arachis hypogaea , cultivated in Tunisia

International audienceThis manuscript reports the complete and circularized Oxford Nanopore Technologies (ONT) long read-based genome sequences of five nitrogen-fixing symbionts belonging to the genus Bradyrhizobium , isolated from root nodules of peanut ( Arachis hypogaea ) grown on soil samples collected from Tunisia

High Variability and Rapid Evolution of a Nanovirus▿ †

Nanoviruses are multipartite single-stranded DNA (ssDNA) plant viruses that cause important diseases of leguminous crops and banana. Little has been known about the variability and molecular evolution of these viruses. Here we report on the variability of faba bean necrotic stunt virus (FBNSV), a nanovirus from Ethiopia. We found mutation frequencies of 7.52 × 10−4 substitutions per nucleotide in a field population of the virus and 5.07 × 10−4 substitutions per nucleotide in a laboratory-maintained population derived thereof. Based on virus propagation for a period of more than 2 years, we determined a nucleotide substitution rate of 1.78 × 10−3 substitutions per nucleotide per year. This high molecular evolution rate places FBNSV, as a representative of the family Nanoviridae, among the fastest-evolving ssDNA viruses infecting plants or vertebrates