Elucidating variations in the nucleotide sequence of Ebola virus associated with increasing pathogenicity

Background Ebolaviruses cause a severe and often fatal haemorrhagic fever in humans, with some species such as Ebola virus having case fatality rates approaching 90%. Currently, the worst Ebola virus outbreak since the disease was discovered is occurring in West Africa. Although thought to be a zoonotic infection, a concern is that with increasing numbers of humans being infected, Ebola virus variants could be selected which are better adapted for human-to-human transmission. Results To investigate whether genetic changes in Ebola virus become established in response to adaptation in a different host, a guinea pig model of infection was used. In this experimental system, guinea pigs were infected with Ebola virus (EBOV), which initially did not cause disease. To simulate transmission to uninfected individuals, the virus was serially passaged five times in naïve animals. As the virus was passaged, virulence increased and clinical effects were observed in the guinea pig. An RNAseq and consensus mapping approach was then used to evaluate potential nucleotide changes in the Ebola virus genome at each passage. Conclusions Upon passage in the guinea pig model, EBOV become more virulent, RNA editing and also coding changes in key proteins become established. The data suggest that the initial evolutionary trajectory of EBOV in a new host can lead to a gain in virulence. Given the circumstances of the sustained transmission of EBOV in the current outbreak in West Africa, increases in virulence may be associated with prolonged and uncontrolled epidemics of EBOV

Filovirus RefSeq Entries: Evaluation and Selection of Filovirus Type Variants, Type Sequences, and Names

Sequence determination of complete or coding-complete genomes of viruses is becoming common practice for supporting the work of epidemiologists, ecologists, virologists, and taxonomists. Sequencing duration and costs are rapidly decreasing, sequencing hardware is under modification for use by non-experts, and software is constantly being improved to simplify sequence data management and analysis. Thus, analysis of virus disease outbreaks on the molecular level is now feasible, including characterization of the evolution of individual virus populations in single patients over time. The increasing accumulation of sequencing data creates a management problem for the curators of commonly used sequence databases and an entry retrieval problem for end users. Therefore, utilizing the data to their fullest potential will require setting nomenclature and annotation standards for virus isolates and associated genomic sequences. The National Center for Biotechnology Information’s (NCBI’s) RefSeq is a non-redundant, curated database for reference (or type) nucleotide sequence records that supplies source data to numerous other databases. Building on recently proposed templates for filovirus variant naming [ ()////-], we report consensus decisions from a majority of past and currently active filovirus experts on the eight filovirus type variants and isolates to be represented in RefSeq, their final designations, and their associated sequences

Virus nomenclature below the species level : a standardized nomenclature for filovirus strains and variants rescued from cDNA

Specific alterations (mutations, deletions, insertions) of virus genomes are crucial for the functional characterization of their regulatory elements and their expression products, as well as a prerequisite for the creation of attenuated viruses that could serve as vaccine candidates. Virus genome tailoring can be performed either by using traditionally cloned genomes as starting materials, followed by site-directed mutagenesis, or by de novo synthesis of modified virus genomes or parts thereof. A systematic nomenclature for such recombinant viruses is necessary to set them apart from wild-type and laboratoryadapted viruses, and to improve communication and collaborations among researchers who may want to use recombinant viruses or create novel viruses based on them. A large group of filovirus experts has recently proposed nomenclatures for natural and laboratory animal-adapted filoviruses that aim to simplify the retrieval of sequence data from electronic databases. Here, this work is extended to include nomenclature for filoviruses obtained in the laboratory via reverse genetics systems. The previously developed template for natural filovirus genetic variant naming,\virus name[(\strain[/)\isolation host-suffix[/ \country of sampling[/\year of sampling[/\genetic variant designation[-\isolate designation[, is retained, but we propose to adapt the type of information added to each field for cDNA clone-derived filoviruses. For instance, the full-length designation of an Ebola virus Kikwit variant rescued from a plasmid developed at the US Centers for Disease Control and Prevention could be akin to ‘‘Ebola virus H.sapiens-rec/COD/1995/Kikwit-abc1’’ (with the suffix ‘‘rec’’ identifying the recombinant nature of the virus and ‘‘abc1’’ being a placeholder for any meaningful isolate designator). Such a full-length designation should be used in databases and the methods section of publications. Shortened designations (such as ‘‘EBOV H.sap/COD/95/ Kik-abc1’’) and abbreviations (such as ‘‘EBOV/Kik-abc1’’) could be used in the remainder of the text, depending on how critical it is to convey information contained in the full-length name. ‘‘EBOV’’ would suffice if only one EBOV strain/variant/isolate is addressed.http://link.springer.com/journal/705hb201

The work program of discipline „Bases of economics” for technical specialties

Посібник містить зміст короткого курсу економічної теорії та загальних основ економічних знань з урахуванням потреб підготовки молодших спеціалістів, бакалаврів та магістрів технічних спеціальностей. The manual contains the content of short course of economics and general bases of economic knowledge taking into account the necessities of preparation of junior specialists, bachelors and master’s degrees in technical specialties

Work program of the discipline „Bases of economics” for full-time and part-time students studying in the fields of knowledge 13 "Mechanical engineering", specialties 131 "Applied Mechanics", 133 "Sectoral engineering", 274 "Automobile transport", 192 "Construction and civil engineering"

Посібник містить зміст короткого курсу економічної теорії та загальних основ економічних знань з урахуванням потреб підготовки молодших спеціалістів, бакалаврів та магістрів технічних спеціальностей. The manual contains the content of short course of economics and general bases of economic knowledge taking into account the necessities of preparation of junior specialists, bachelors and master’s degrees in technical specialties

Work program of the discipline „Bases of economics” for full-time and part-time students studying in the fields of knowledge 12 "Information Technologies", 20 "Agrarian Sciences and Food", 13 "Mechanical Engineering"; specialties 123 "Computer engineering", 208 "Agroengineering", 131 "Applied mechanics", 133 "Sectoral engineering"

Посібник містить зміст короткого курсу економічної теорії та загальних основ економічних знань з урахуванням потреб підготовки молодших спеціалістів, бакалаврів та магістрів технічних спеціальностей. The manual contains the content of short course of economics and general bases of economic knowledge taking into account the necessities of preparation of junior specialists, bachelors and master’s degrees in technical specialties