Diversity and biosynthetic potential of culturable aerobic heterotrophic bacteria isolated from Magura Cave, Bulgaria

Biocapacity of bacteria inhabiting karstic caves to produce valuable biologically active compounds is still slightly investigated. A total of 46 culturable heterotrophic bacteria were isolated under aerobic conditions from the Gallery with pre-historical drawings in Magura Cave, Bulgaria. Phylogenetic analysis revealed that most of bacterial isolates aff iliated with Proteobacteria (63%), followed by Actinobacteria (10.9%), Bacteroidetes (10.9%), and Firmicutes (6.5%). A strong domination of Gram-negative bacteria (total 81%) belonging to nine genera: Serratia, Pseudomonas, Enterobacter, Sphingobacterium, Stenotrophomonas, Commamonas, Acinetobacter, Obesumbacterium, and Myroides, was observed. Gram-positive isolates were represented by the genera Bacillus, Arthrobacter, and Micrococcus. One isolate showed a signif icant phylogenetic distance to the closest neighbor and could represent а novel species. Heterotrophic bacterial isolates from Magura Cave were investigated for hydrolytic enzymes production, antimicrobial and hemolytic activity. Predominance of producers of protease (87%), followed by xanthan lyase (64%), lipase (40%), β-glycosidase (40%), and phytase (21%) was observed. Over 75% of the isolates demonstrated antimicrobial and hemolytic activity. The results suggest that heterotrophic bacteria isolated from Magura Cave could be a valuable source of industrially relevant psychrotolerant enzymes and bioactive metabolites. This study is a f irst report on the taxonomic composition and biological activity of culturable bacteria inhabiting a cave in Bulgaria

Archaeal and bacterial diversity in two hot springs from geothermal regions in Bulgaria as demostrated by 16S rRNA and GH-57 genes

Archaeal and bacterial diversity in two Bulgarian hot springs, geographically separated with different tectonic origin and different temperature of water was investigated exploring two genes, 16S rRNA and GH-57. Archaeal diversity was significantly higher in the hotter spring Levunovo (LV) (82°C); on the contrary, bacterial diversity was higher in the spring Vetren Dol (VD) (68°C). The analyzed clones from LV library were referred to twenty eight different sequence types belonging to five archaeal groups from Crenarchaeota and Euryarchaeota. A domination of two groups was observed, Candidate Thaumarchaeota and Methanosarcinales. The majority of the clones from VD were referred to HWCG (Hot Water Crenarchaeotic Group). The formation of a group of thermophiles in the order Methanosarcinales was suggested. Phylogenetic analysis revealed high numbers of novel sequences, more than one third of archaeal and half of the bacterial phylotypes displayed similarity lower than 97% with known ones. The retrieved GH-57 gene sequences showed a complex phylogenic distribution. The main part of the retrieved homologous GH-57 sequences affiliated with bacterial phyla Bacteroidetes, Deltaproteobacteria, Candidate Saccharibacteria and affiliation of almost half of the analyzed sequences is not fully resolved. GH-57 gene analysis allows an increased resolution of the biodiversity assessment and in depth analysis of specific taxonomic groups. [Int Microbiol 18(4):217-223 (2015)]Keywords: Archaea · hot spring · phylogenetic analysis · 16S rRNA gene · GH-57 gen

Diversity and biosynthetic potential of culturable aerobic heterotrophic bacteria isolated from Magura Cave, Bulgaria

Biocapacity of bacteria inhabiting karstic caves to produce valuable biologically active compounds is still slightly investigated. A total of 46 culturable heterotrophic bacteria were isolated under aerobic conditions from the Gallery with pre-historical drawings in MaguraCave, Bulgaria. Phylogenetic analysis revealed that most of bacterial isolates affiliated with Proteobacteria (63%), followed by Actinobacteria (10.9%), Bacteroidetes (10.9%), and Firmicutes (6.5%). A strong domination of Gram-negative bacteria (total 81%) belonging to nine genera: Serratia, Pseudomonas, Enterobacter, Sphingobacterium, Stenotrophomonas, Commamonas, Acinetobacter, Obesumbacterium, and Myroides, was observed. Gram-positive isolates were represented by the genera Bacillus, Arthrobacter, and Micrococcus. One isolate showed a significant phylogenetic distance to the closest neighbor and could represent а novel species. Heterotrophic bacterial isolates from MaguraCave were investigated for hydrolytic enzymes production, antimicrobial and hemolytic activity. Predominance of producers of protease (87%), followed by xanthan lyase (64%), lipase (40%), β-glycosidase (40%), and phytase (21%) was observed. Over 75% of the isolates demonstrated antimicrobial and hemolytic activity. The results suggest that heterotrophic bacteria isolated from MaguraCave could be a valuable source of industrially relevant psychrotolerant enzymes and bioactive metabolites. This study is a first report on the taxonomic composition and biological activity of culturable bacteria inhabiting a cave in Bulgaria

GEOPHYSICAL AND GEOTECHNICAL EXPLORATIONS ON THE FORTRESS ISAR – ŠTIP

The aim of this paper is to define the geotechnical and seismic-geological characteristics of the terrain of the investigated аrea, the local disorders and discontinuities that indicate the presence of weakened and disintegrated zones. The research is performed using the geotechnical investigations and seismic refractive method and consists of field measurements, processing and analysis of the obtained results. The object of the investigation is the Acropolis of the fortress Isar. Analyzing the obtained data, three lithological environments are distinguished which are characterized by different physical and mechanical characteristics. The following lithological environments are distinguished: surface layer made of deluvium and crushed material from a mother rock reaching an interval of 0–4 m; subsurface zone consisting of a fragmented degraded mother rock with a depth of 6 to 10 m, characterized by quite poor physical-mechanical characteristics and represents a critical zone; intensely cracked rocks at depths greater than 10 m where the physical-mechanical characteristics of the rock are improved. Key words: exploration; geotechnics; seismic method; refraction; tomography; fortress Isa

Geophysical and geotechnical explorations on the fortress Isar – Štip

The aim of this paper is to define the geotechnical and seismic-geological characteristics of the terrain of the investigated аrea, the local disorders and discontinuities that indicate the presence of weakened and disintegrated zones. The research is performed using the geotechnical investigations and seismic refractive method and consists of field measurements, processing and analysis of the obtained results. The object of the investigation is the Acropolis of the fortress Isar. Analyzing the obtained data, three lithological environments are distinguished which are characterized by different physical and mechanical characteristics. The following lithological environments are distinguished: surface layer made of deluvium and crushed material from a mother rock reaching an interval of 0–4 m; subsurface zone consisting of a fragmented degraded mother rock with a depth of 6 to 10 m, characterized by quite poor physical-mechanical characteristics and represents a critical zone; intensely cracked rocks at depths greater than 10 m where the physical-mechanical characteristics of the rock are improved

HIGH PHYLOGENETIC DIVERSITY OF BACTERIA IN THE AREA OF PREHISTORIC PAINTINGS IN MAGURA CAVE, BULGARIA

Abstract: Magura Cave, situated in the northwest of Bulgaria and containing prehistoric paintings, is a famous tourist site. The present study is the first report on bacterial diversity in guano paintings in a Bulgarian cave using molecular methods. We identified 68 taxa, which is an unusually high number for oligotrophic niches. They are affiliated with eight phyla representing more than half of the bacterial divisions identified in caves. As in many other caves, Proteobacteria dominated in this type of ecosystem (about 40%), followed by Nitrospirae (22.5%) and Acidobacteria (21.5%). Weakly represented were Actinobacteria (6.4%), Chloroflexi (3.2%), Planctomycetes (2.2%), Firmicutes (2.2%), and Gemmatimonadetes (2.2%). About one third of all DNA sequences recovered in this study were new. Some of them had more than 10% divergence from the closest neighbor, which suggests the existence of new taxa of at least genus level. Bacteria identified in the community expressed various types of metabolism; lithoautotrophic, organotrophic, and methylotrophic

Phytochemical Constituents and Pharmacological Potential of Tamus communis Rhizomes

Tamus communis L. is a plant distributed in a number of geographical areas whose rhizome has been used for centuries as an anti-inflammatory and analgesic remedy. This review aims to summarize the current knowledge of the chemical composition and biological activity of the extracts or individual compounds of the rhizome. The data for the principal secondary metabolites are systematized: sterols, steroidal saponins, phenanthrenes, dihydrophenanthrenes, etc. Results of biological tests for anti-inflammatory action, cytotoxicity, anticholinesterase effect, and xanthine oxidase inhibition are presented. Some open questions about the therapeutic properties of the plant are also addressed

Combining Repetitive Transcranial Magnetic Stimulation and Cognitive Behavioral Therapy for Effective Treatment of Tinnitus and Insomnia - A Case Report

We present the case of a 53-year-old male patient, who had been suffering from symptoms of decompensated and chronified tinnitus for four years, most likely caused by work stress. In addition, the patient developed comorbid decompensated insomnia.Because of potential bidirectional connections between tinnitus and sleep disorders, an interdisciplinary approach to treatment was chosen.The treatment plan we developed consisted of ten sessions of repetitive transcranial magnetic stimulation (rTMS) for tinnitus, followed by ten sessions of cognitive behavioral therapy (CBT) for tinnitus and insomnia. We used the Tinnitus Questionnaire (TF) to assess tinnitus severity, the Beck Depression Inventory (BDI-II) for depressive symptoms, as well as the WHO Well-being Index (WHO-5) for subjective well-being. Improvements were achieved with regard to everyday functioning, as the patient went from decompensated and severe to clinically negligible TF scores, from minimal to no depressive symptoms, and from just above critical to above average well-being. Combining equipment- based and psychological approaches to treatment proved to be successful in this case. We conclude that a combination of rTMS and CBT may be considered as an effective treatment for chronic tinnitus and comorbid sleep disorders

Ginkgo biloba Seeds—An Environmental Pollutant or a Functional Food

Ginkgo biloba has been cultivated in Bulgaria since the end of the 19th century. Ividual specimens can be seen in almost every park. Females of the tree are considered contaminants of the landscape because their ripe seeds have a strong odor and are not utilized. We undertook this study to clarify whether ginkgo seeds of local origin can be converted from an unwanted and unused environmental pollutant into a source of beneficial compounds. Various analytical and chromatographic methods were used to quantify the major constituents and ten biologically active compounds in methanol seed extract. The results showed that the seeds are low in proteins (5%) and fats (1%); the seeds were also rich in unsaturated fatty acids and tocopherols. About 44% of nut starch was resistant to in vitro enzymatic hydrolysis. The amount of terpene trilactones in an aqueous-methanol seed extract was significantly higher than the number of flavonoids. Ginkgotoxin and ginkgolic acid were also found. The extract demonstrated weak antimicrobial activity against thirteen microorganisms. This study revealed that seeds of locally grown Ginkgo trees can be used as a source of biologically active substances. The chemical composition show similarity to those of seeds from other geographical areas