42 research outputs found
Seroimmunotyping of African swine fever virus
The extreme genetic and immunobiological heterogeneity exhibited by the African swine fever virus (ASFV) has been a significant impediment in the development of an efficacious vaccine against this disease. Consequently, the lack of internationally accepted protocols for the laboratory evaluation of candidate vaccines has become a major concern within the scientific community. The formulation of such protocols necessitates the establishment of a consensus at the international level on methods for the determination of homologous and heterologous isolates/strains of ASFV. The present article provides a comprehensive description of biological techniques employed in the classification of ASFV by seroimmunotypes. These techniques involve a holistic evaluation of ASFV isolates/strains based on their antigenic properties as determined by the hemadsorption inhibiting test (HAdI) using type-specific sera and an immunological test (IT) conducted on pigs inoculated with attenuated strains. The article outlines the methods for setting up the HAdI test, an IT on pigs, and the processes involved in the acquisition of type-specific serums for the HAdI test. It is pertinent to note that the definitive classification of seroimmunotype can only be ascertained after conducting an IT on pigs. The findings from the HAdI test or the phylogenetic analysis of the EP402R gene should be considered preliminary in nature
Remarkable convergent evolution in specialized parasitic Thecostraca (Crustacea)
<p>Abstract</p> <p>Background</p> <p>The Thecostraca are arguably the most morphologically and biologically variable group within the Crustacea, including both suspension feeders (Cirripedia: Thoracica and Acrothoracica) and parasitic forms (Cirripedia: Rhizocephala, Ascothoracida and Facetotecta). Similarities between the metamorphosis found in the Facetotecta and Rhizocephala suggests a common evolutionary origin, but until now no comprehensive study has looked at the basic evolution of these thecostracan groups.</p> <p>Results</p> <p>To this end, we collected DNA sequences from three nuclear genes [18S rRNA (2,305), 28S rRNA (2,402), Histone H3 (328)] and 41 larval characters in seven facetotectans, five ascothoracidans, three acrothoracicans, 25 rhizocephalans and 39 thoracicans (ingroup) and 12 Malacostraca and 10 Copepoda (outgroup). Maximum parsimony, maximum likelihood and Bayesian analyses showed the Facetotecta, Ascothoracida and Cirripedia each as monophyletic. The better resolved and highly supported DNA maximum likelihood and morphological-DNA Bayesian analysis trees depicted the main phylogenetic relationships within the Thecostraca as (Facetotecta, (Ascothoracida, (Acrothoracica, (Rhizocephala, Thoracica)))).</p> <p>Conclusion</p> <p>Our analyses indicate a convergent evolution of the very similar and highly reduced slug-shaped stages found during metamorphosis of both the Rhizocephala and the Facetotecta. This provides a remarkable case of convergent evolution and implies that the advanced endoparasitic mode of life known from the Rhizocephala and strongly indicated for the Facetotecta had no common origin. Future analyses are needed to determine whether the most recent common ancestor of the Thecostraca was free-living or some primitive form of ectoparasite.</p
BIOLOGICAL PROPERTIES AND MOLECULAR-GENETIC CHARACTERISTICS OF BACILLUS ANTHRACIS STRAINS, ISOLATED DURING THE OUTBREAK OF ANTHRAX IN THE YAMALO-NENETS AUTONOMOUS DISTRICT IN 2016
Objective of the study was to identify phenotypic properties and genetic peculiarities of Bacillus anthracis strains, isolated during the outbreak of anthrax in the territory of Yamal in 2016. Materials and methods. Investigated were the strains of anthrax agent, applying basic and subsequent identification tests and canSNP-, MLVA-genotyping methods and whole genome sequencing. Results and conclusions. The results showed the identity of the phenotypic properties, canSNPand MLVA25-genotypes, and profiles of whole genome-sequencing, regardless of the source of the strains isolation. Confirmed was a common source of human infection. Defined were phylogenetic interrelations of the tested strains and their position in global B. anthracis population. For the first time ever explored was variability of the gene pattern, associated with pathogenicity, and demonstrated – the efficiency of the proposed algorithm for genetic typing
Progress in International Radioactive Fusion Waste Studies
The International Energy Agency (IEA) has been promoting the IEA Environment, Safety and Economic Aspects of Fusion Power program for many years. Among the tasks of this program, one task in particular deals with radioactive waste management in order to analyze the issue of the final destination of fusion activated and tritiated materials after their use in a fusion power reactor. A collaborative study on these aspects has been carried out in recent years. An optimized waste management strategy is proposed, with the goals of avoiding underground disposal as much as possible, maximizing recycling of activated materials within the nuclear industry, and/or clearance and release to commercial markets if materials contain only slight traces of radioactivity. Some technological problems and recent research advances in this field are summarized
Photoelectrochemical, photocatalytic and electrocatalytic behavior of titania films modified by nitrogen and platinum species
Co-doping of titania by N and Pt species was employed to tune the electronic structure and enhance the electrocatalytic and photocatalytic activity of the films. Herein, the different approaches of synthesis procedure of Pt- and Pt,N–TiO2 films were used to investigate their effect on the platinum oxidation states. The resulting different species of Pt led to the changes in the electronic structure of TiO2, with consequent bandgap narrowing, anodic shift of the flat band potential, and cathodic shift of the valence band The quantum yield efficiency was correlated with Pt0 atomic content and the relative atomic content of Ptn+–O–Ti fragments, whereas its decrease for some samples can be caused by the presence of N and Ptn+. The highest response for N2O photocatalytic decomposition was observed over Pt,N–TiO2 films. The presence of metal and non-metal species in TiO2 structure resulted in synergistic effect including (1) inhibition of recombination of the electrons and holes and (2) narrowing of the bandgap. Electrocatalytic properties in hydrogen and oxygen evolution reactions were improved by Pt doping. The formed Pt2+–O–Ti bonds rather than Pt nanoparticles are suggested to be responsible for the highest electrocatalytic activity. The additional UV exposure of the electrodes led to Pt NPs aggregation as a result of photodeposition of Pt ions. The mechanism of the Pt2+ photoreduction in TiO2 structure is proposed.Peer reviewe
Spatio-temporal kriging analysis to identify the role of wild boar in the spread of African swine fever in the Russian Federation
The current situation of African Swine Fever (ASF) epidemic in continental Europe represents a serious economic risk for the European pig industry. It is well known that both domestic pigs and wild boar are involved in the ASF spread, but the exact mechanism of the domestic–wildlife interface remains under research. A spatio-temporal kriging analysis was carried out to estimate the most possible source of infection (domestic pigs or wild boar) for 1,323 notifications of ASF reported in the Russian Federation (RF) from 2013 to 2017. Results for the whole period of study showed that domestic pigs and wild boar were the potential source of infection for 55% and 45% of notifications, respectively. The analysis stratified by year showed fluctuation in this tendency through time. At the early stages of the ASF epidemic in the Southern regions of the RF in 2007–2008 wild boar appears to be the main source of infection, while the following stage of the epidemic in 2009–2012 may be more related to a domestic source of infection. At the latter stage of the epidemic (2013–2017) both, domestic and wild boar, play a similar role as a source of the disease in the newly infected areas but differences by geographical locations can be observed matching with the epidemiology of the disease. This paper provides useful information for better understanding of the ASF mechanism and domestic–wildlife interactions in the RF and describes a new spatio-temporal approach that can be easily applied to other similar animal diseases with a domestic–wildlife interface
Immunohistochemical characteristics of bladder cancer in patients with virus-positive tumors
Background. Viral infection is a major factor in virus-associated carcinogenesis.Objective: to evaluate the expression of growth factors and markers of apoptosis, proliferative activity, and angiogenesis in patients with viral DNA-positive bladder cancer.Materials and methods. The study included 100 bladder cancer patients (72 males and 28 females) aged between 38 and 90 years (mean age 65 ± 10). Tumor tissue samples were tested by polymerase chain reaction to detect DNA of herpes simplex virus types 1 and 2 (HSV-1 and HSV-2 respectively), high-risk human papillomavirus (HPV), cytomegalovirus (CMV), and Epstein—Barr virus (EBV). Immunohistochemical analysis was performed in 32 patients and included the following markers: proliferation marker Ki-67, p63, apoptosis regulator Bcl-2, p53, angiogenesis marker CD31, adhesion protein CD44, and epidermal growth factor receptor (EGFR).Results. Viral DNA in tumor tissue was detected in 34 patients; of them, 50 % had poorly-differentiated tumors. Twenty-seven patients were found to have EBV DNA in their tumor tissue; 6 patients had CMV DNA; 5 patients had high-risk HPV DNA (types 16, 39, 45, 52, and 59); 1 patient had HSV1 and HSV2 DNA. Four out of 34 participants had mixed infections (1 case of HPV 59 + EBV; 2 cases of EBV + CMV; 1 case of CMV + EBV + HPV 31 and 52). We observed a strong correlation between the presence of EBV DNA and levels of CD31 and Ki-67 expression as well as between high-risk HPV DNA and Bcl-2 expression. High levels of antibodies against EBV capsid antigen were associated with EGFR and Ki-67 expression, whereas the level of antibodies against EBV nuclear antigen correlated with CD44 expression. We evaluated specific characteristics of expression of the markers analyzed depending on the tumor stage, grade of anaplasia, and recurrence. We also assessed morphological characteristics of changes in lymphocytic and plasma cell infiltrates.Conclusion. We found a correlation between the presence of viral DNA in bladder cancer tissue and markers of proliferative activity, angiogenesis, and apoptosis. Viral infection is likely to increase proliferative activity and suppression of apoptosis, which may cause tumor progression. Further studies are needed to assess this correlation
Reproductive ratio for the local spread of African swine fever in wild boars in the Russian Federation
African swine fever (ASF) has caused the swine industry of the Russian Federation substantial economic losses over the last 7 years, and the disease spread from there to a number of neighbouring countries. Wild boar has been involved in the spread of the disease both at local and at transboundary levels. Understanding ASF dynamics in wild boars is prerequisite to preventing the spread and to designing and applying effective surveillance and control plans. The reproductive ratio (R0) is an epidemiological indicator commonly used to quantify the extent of disease spread. Here, it was estimated in nine spatio-temporal clusters of ASF in wild boar cases in the Russian Federation (2007–2013). Clusters were defined by exploring the maximum distance of association of ASF cases using K Ripley analysis and spatio-temporal scan statistics. A maximum spatial association of 133 km in wild boar cases was identified which is within de the conventional radius of surveillance zone (100–150 km). The mean range value of R0 = 1.58 (1.13–3.77) was lower compared to values previously estimated for ASF transmission within farms but similar to early estimates between farm (R0 = 2–3), in domestic pigs using notification data in the Russian Federation. Results obtained provide quantitative knowledge on the epidemiology of ASF in wild boars in the Russian Federation. They identify the ASF transmission rate value in affected natural wild populations, for the first time, which could provide basis for modelling ASF transmission and suggest that current surveillance radius should be reviewed to make surveillance in wild nature more targeted and effective. © 2015 Blackwell Verlag Gmb