Impact of sharp weather warming on the exchangeable forms of 137Cs in soils and its bioaccumulation in orchard grass

Broomrapes are root holoparasites from Orobanchaceae family parasitizing other flowering plants. Several of the most aggressive broomrape species are widely spread in Bulgaria often causing serious yield losses of important crops. It is important to be able to detect the presence of broomrape seeds in the soil. In the present study, we combined a proven PCR-based assay for detection of broomrape seeds with methods to distinguish species based on nuclear ITS sequences to identify broomrape seeds isolated from soil samples and to study the population structure and the intraspecific variations within the three species. Fifty-six soil samples from 23 different regions in Bulgaria were studied. Based on molecular and bioinformatics analyses we found that 22 samples contained seeds of Orobanche cernua var. cumana and six samples, seeds of Phelipanche ramosa. Phylogenic and bioinformatics analyses surprisingly revealed that the isolated sequences from supposedly P. mutelii seeds diverge from those annotated in NCBI by other authors on 16 different nucleotide positions and formed two distant branches of the phylogenic tree. On the other hand, the isolated sequences were almost identical with P. rosmarina. Tajimas’ D-test revealed that O. cumana populations are currently stable. Regarding the Phelipanche representatives, based on the D-test we can hypothesize that P. mutelii/P. rosmarina populations are in a period of active expansion, while P. ramosa populations are contracting. All isolated sequences were deposited in NCBI Genbank database.

ABSTRACTIt is known that the variation in tobacco indicators is mainly determined by the harvest belt (the biological factor) and the crop (the climatic factor), and less by the region and microregion of growing (soil-climatic and agrobiological factors). It has been established in a research of the quality of Burley tobacco, produced in different regions in Bulgaria that the Bulgarian Burley tobacco corresponds to the type according by general quality, but it has some specific peculiarities due to the specific conditions of growing. The purpose of the present study is the comparative technological investigation of the tobacco of Burley variety group, grown in different regions in Bulgaria, with the view of establishing the typical for the variety high quality. The samples taken from different regions of the country have been analyzed with respect to the main technological indicators, describing their quality. The results obtained show that there are no clearly expressed differences as to the quality between the Burley tobacco variety produced in the different regions in Bulgaria. By complex quality estimation they suit the requirements for this type of tobacco, and more specifically with respect to the objective chemical indicators. When applying appropriate agricultural equipment, as well as under favourable climatic conditions (crop), they possess qualities that meet the purchasers' requirements towards this tobacco type according to its consumption.

137Cs, 239,240Pu and 241Am in boreal forest soil and their transfer into wild mushrooms and berries

Cs-137 distribution in forest floor and surface soil layers from two mountainous regions in Bulgaria

Modeling dynamics of 137Cs in forest surface environments: Application to a contaminated forest site near Fukushima and assessment of potential impacts of soil organic matter interactions

One of the best documented Indo-European civilizations that inhabited Bulgaria is the Thracians, who lasted for more than five millennia and whose origin and relationships with other past and present-day populations are debated among researchers. Here we report 25 new complete mitochondrial genomes of ancient individuals coming from three necropolises located in different regions of Bulgaria – Shekerdja mogila, Gabrova mogila and Bereketska mogila – dated to II-III millennium BC. The identified mtDNA haplogroup composition reflects the mitochondrial variability of Western Eurasia. In particular, within the ancient Eurasian genetic landscape, Thracians locate in an intermediate position between Early Neolithic farmers and Late Neolithic-Bronze Age steppe pastoralists, supporting the scenario that the Balkan region has been a link between Eastern Europe and the Mediterranean since the prehistoric time. Spatial Principal Component Analysis (sPCA) performed on Thracian and modern mtDNA sequences, confirms the pattern highlighted on ancient populations, overall indicating that the maternal gene pool of Thracians reflects their central geographical position at the gateway of Europe.

Mycobacterium tuberculosis isolates from different regions of Bulgaria were studied by a variety of molecular typing tools. Based on spacer oligonucleotide typing (spoligotyping), the 113 strains were subdivided into 35 spoligotypes: 5 unique profiles and 15 profiles shared by two to 29 strains; the Hunter-Gaston diversity index (HGI) was 0.9. Comparison with the international database SITVIT2 at the Institut Pasteur de Guadeloupe showed the presence of two globally distributed shared types, ST53 (25.7%) and ST47 (6.2%). Nineteen (16.8%) and six (5.3%) strains belonged to the ST125 (LAM/S subfamily) and ST41 (LAM7_TUR subfamily) types described in SITVIT2 as ubiquitous/rare and ubiquitous/common types, respectively. Seven spoligoprofiles (12 strains) were not found in the database; two of them constituted new shared types. The Beijing genotype strains were not found in the studied collection in spite of close contacts with Russia in the recent and historical past. Additional subtyping by IS6110-restriction fragment length polymorphism (RFLP) and 12-locus mycobacterial interspersed repetitive unit (MIRU)-variable number of tandem repeat analyses were performed within selected spoligotypes. In particular, MIRU typing showed better discrimination within ST125 than IS6110-RFLP typing (HGI = 0.83 versus 0.39). A high gradient for ST125 in Bulgaria compared to its negligible presence in the global database and neighboring countries leads us to suggest a Bulgarian phylogeographic specificity of this spoligotype. To conclude, this first study of the Bulgarian M. tuberculosis population demonstrated its heterogeneity and predominance of several worldwide-distributed and Balkan-specific spoligotypes.

This article analyses the content of natural radionuclides in chamomile plants collected from two different locations. Both samples have been dried in the shade at room temperature. The chamomile has been collected in July 2016 from two different regions of Bulgaria - Yagnilo village, Varna district and the village of Debeli Rat, Veliko Tarnovo district. They are dried under natural conditions and milled into a fine powder. The measurements are taken on a low-background spectrometer at Shumen University Episkop Konstantin Preslavski. The resulting gamma-spectra are processed with ANGES software. Radioisotopes are determined by their energies. The values of their specific activities are calculated. Approximately the same levels of 226 Ra, 228 Ac, 208 T1 and 40 K are found in the samples from both regions. The highest levels of radionuclides are meаsured for 40 K, the lowest specific activity in the flowers from Yagnilo is found for 208 Tl, and in those from Debeli Rat - for 212 Pb. The levels of their specific activities are within the limits, according to Ordinance №25 on the requirements for protection of people in case of chronic irradiation, as a result of production, trade and use of raw materials, products and goods with increased content of radionuclides and Ordinance №11 on defining the terms and conditions for providing free food and/or supplements to the workers and employees who work in enterprises of a specific nature and organization of work. The public health of consumers is not at risk, given these levels.

In 1990 an increased number of strains of Shigella boydii serotype 2 were isolated from different regions of Bulgaria. Strains were reported as sporadic, although they showed identical phenotypic characteristics, including resistance to ampicillin, carbenicillin, streptomycin, sulfonamide, tetracycline, ticarcillin, and trimethoprim. The objective of this study was to determine the genetic relatedness of the strains and the mechanism of their antimicrobial resistance. Plasmid fingerprinting showed an identical pattern for 23 of 25 of the selected strains. All 25 strains tested transferred their resistances en bloc to an Escherichia coli recipient. Transconjugants contained a 112-kb R plasmid which carried all the resistance genes, including that conferring type I dihydrofolate reductase-mediated trimethoprim resistance (MIC greater than 2,000 micrograms/ml). Riboprobe analysis showed identical restriction length fragment polymorphisms, suggesting a highly conserved genome. All findings indicate that strains of S. boydii serotype 2 isolated in 1990 from different regions of Bulgaria were highly related genetically and can be considered representatives of a single bacterial clone. The presence of an R plasmid and selection pressure because of the usage of antimicrobial agents, particularly trimethoprim, have likely facilitated the spread of the clone throughout the country.

Forest fires annually affect large areas all over the world. They are one of the reasons for changes in the forest ecosystems, which lead to unpredictable consequences in long term. The present research extends and builds up an analysis of the forest fires risk assessment in Bulgaria over the last 20 years. Two methodologies, different in their essence, are used in the study: a common approach (Lubenov’s methodology) and InterCriteria Analysis (ICrA). Lubenov’s methodology classifies the different regions of Bulgaria in groups according to the risk of forest fires. ICrA, which seeks to find relations between some predefined criteria, is used as an additional approach to refine this classification. The research is based on the number of the forest fires occurred in different regions of Bulgaria and the size of the burned areas over the past 20 years. Expanding the period over which the study is conducted aims for the Lubenov’s methodology to confirm the results of ICrA.KeywordsForest fire riskInterCriteria AnalysisIntuitioninstic fuzzy setsIndex Matrices

The article reveals the peculiarities of migration processes of the Bulgarians to the Ural regions, the formation and development of Bulgarian communities in the 1920s - 1930s. The main sources of the study include archival documents, especially the materials of investigation cases and statistical outputs that are introduced into scientific circulation for the first time. The study defines two migration flows of the Bulgarians to the Ural - from the places of their traditional settlement in the Western regions of the USSR due to collectivization and dispossession of kulaks and from different regions of Bulgaria - as a consequence of political emigration. Ural Bulgarians that came to the region as a result of voluntary and forced migrations took part in industrialization process and worked mainly in industrial enterprises and forestry administration. Many of them were subjected to repressions during the period of 1937-1938.

This paper deals with the influence of sharp temperature variations on the geochemical fractionation and bioavailability of 241Am, 60Co and 137Cs in Fluvisol soil. The study was performed using soil contaminated with aqueous solutions of 241Am, 60Co and 137Cs in the laboratory and stored for three years at temperatures within the range of 10–18 oC and soil moisture from 20 to 30 wt %. Afterward the soil was divided into three equal parts and conditioned for one month at 10–18 oC, −18 oC and 40 oC temperature regimes, respectively. The impact of the storage conditions on geochemical forms of the radionuclides was investigated using single extraction of exchangeable 137Cs with 1 M NH4NO3 and sequential extraction of 241Am and 60Co, and by gamma-spectrometric measurement. The influence of temperature rise up to 40 oC over a period of one month on the transfer factors (TFs) of the radionuclides from the investigated soil to orchard grass (Dactylis glomerata L.) was evaluated. The results showed that deep free...

The ratio of plant 137Cs to exchangeable 137Cs in soil is a crucial factor in explaining the variation in 137Cs transferability from soil to plant.

The investigation of 137Cs and 90Sr background radiation levels in soil and plant around Tianwan NPP, China

Migration of 137Cs in soils and its transfer to mushrooms and vascular plants in mixed forest