Vol 32, No 1 (2017)

In Bacillus anthracis, an alternative to the use of chelating agents (siderophores) for acquiring iron consists in using a system of hemophores and transporter proteins for scavenging hemes from hemoglobin and delivering them into the bacterial cell. B. anthracis utilizes the siderophore-mediated mechanism of acquiring iron predominantly at the intracellular stage of its development, with the system of hemophores and transporter proteins being used at the extracellular stage of anthrax infection. The structure, genetic organization, and functions of the system for heme iron acquisition in B. anthracis, understanding of which may facilitate the development of new therapies for anthrax, are discussed.

The review contains some brief information on cholera epidemics in Africa. Comparative analysis of the results of whole-genome sequencing of 30 clinical strains isolated in Africa in different periods of the seventh cholera pandemic (1985–2012) and data from GenBank revealed their great genetic diversity. It is demonstrated that cholera epidemics in Africa, which began in 1970, were caused for about two decades by typical strains of the pathogen brought from India and Bangladesh. Currently, cholera in Africa is caused by new variants of the pathogen, which originated in Southeast Asia as a result not only of the acquisition of new genes due to horizontal transfer but also alterations in the genomes of previously existing pathogenicity and pandemicity islands. SNP analysis of 53 strains circulating in Africa (30 strains), as well as those isolated in Southeast Asia (23 strains), made it possible to establish phylogenetic relations for the majority of African and Asian strains. The issue of the existence of strains which are apparently endemic for Africa is being discussed. The existing genetic diversity of strains with different levels of virulence and drug resistance indicates the need for continuous molecular monitoring of the causative agent of cholera in Africa.

Mobile genetic elements (in particular, retrotransposons) make up a significant part of eukaryotic genomes and are one of the main sources of genomic variability and instability. More than 60 years have passed already since their discovery, but, nevertheless, certain classes of them, such as Penelope-like elements (PLEs), remain poorly studied. In this work, we present the results of in silico search for PLEs in the genome assembly of the Asian schistosome S. japonicum (one of the most epidemiologically important human parasites). We present a new evaluation of their representation in the S. japonicum genome and showed that their high heterogeneity apparently reflect several transposition events. It was demonstrated that PLEs in the schistosome genome are represented by two groups of canonical copies differing by amino-acid sequences of RT and EN domains. Data on the representation, structural peculiarities, possible functional load, and evolution of Penelope-like retroelements of the parasite are discussed.

In several regions of Russia, broad distribution of RNA-containing bee viruses is found at apiaries of honey bee Apis mellifera using RT-PCR. Detected RNA-containing bee viruses are transferred simultaneously with invasion of mite Varroa destructor and lead to mass bee mortality that results in economic losses in bee breeding. In samples of Varroa destructor, bee viruses DWV and ABPV are found. A high degree of RNA-containing virus (BQCV, DWV SBV, ABPV, CBPV, and KBV) infection is revealed: on average, at least 50% for bee families with mite infection. In the bee families studied in this work, mixed infection with two to six viruses simultaneously is detected. The amplified fragments of viruses BQCV, DWV, and SBV obtained using RT-PCR are sequenced and registered in GenBank.