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In this study, 24 Antarctic bacteria, isolated from sediment and soil samples from Deception and Galindez Islands, were characterized for their antimicrobial activity and response to 13 antibiotics and seven heavy metals. Multiple antibiotic resistance was observed for 67% of sediment isolates and 92% of soil isolates, suggesting medium anthropogenic impact in these Antarctic regions. The results revealed a varying response of the Antarctic bacteria to the tested heavy metals. All isolates showed multiple metal resistance towards two to six heavy metals, with minimum inhibitory concentrations ranging from 1.0 mM to 23.2 mM. The majority of the strains in both groups were resistant to lead, nickel, copper and zinc. Plasmids were detected in 21% of isolates. A consortium of highly metal-resistant bacteria could be developed with potential application for biological treatment of wastewaters. Strains that are highly sensitive to cadmium would be promising for developing biosensors to detect this highly toxic heavy metal in environmental samples. All Antarctic bacteria were found to inhibit the growth of one to all eight of the tested indicator bacteria, and 87% inhibited the growth of one to all four of the yeast indicator cultures. Promising psychrotolerant strains were detected as a valuable source of new antimicrobial compounds.

Synthesis of innovative exocellular polysaccharides (EPSs) was reported for few thermophilic microorganisms as one of the mechanisms for surviving at high temperature. Thermophilic aerobic spore-forming bacteria able to produce exopolysaccharides were isolated from hydrothermal springs in Bulgaria. They were referred to four species, such as Aeribacillus pallidus, Geobacillus toebii, Brevibacillus thermoruber, and Anoxybacillus kestanbolensis. The highest production was established for the strain 418, whose phylogenetic and phenotypic properties referred it to the species A. pallidus. Maltose and NH4Cl were observed to be correspondingly the best carbon and nitrogen sources and production yield was increased more than twofold in the process of culture condition optimization. After purification of the polymer fraction, a presence of two different EPSs, electroneutral EPS 1 and negatively charged EPS 2, in a relative weight ratio 3:2.2 was established. They were heteropolysaccharides consisting of unusual high variety of sugars (six for EPS 1 and seven for EPS 2). Six of the sugars were common for both EPSs. The main sugar in EPS 1 was mannose (69.3 %); smaller quantities of glucose (11.2 %), galactosamine (6.3 %), glucosamine (5.4 %), galactose (4.7 %), and ribose (2.9 %) were also identified. The main sugar in EPS 2 was also mannose (33.9 %), followed by galactose (17.9 %), glucose (15.5 %), galactosamine (11.7 %), glucosamine (8.1 %), ribose (5.3 %), and arabinose (4.9 %). Both polymers showed high molecular weight and high thermostability.

Antarctic plants are stable specific microenvironments for microbial colonization that are still less explored. In this study, we investigated cultivable heterotrophic bacteria and yeasts dominating in plant samples collected from different terrestrial biotopes near Ukrainian Antarctic Base on Galindez Island, maritime Antarctica. Phylogenetic analysis revealed affiliation of the bacterial isolates to genera Pseudomonas, Stenotrophomonas, Brevundimonas, Sporosarcina, Dermacoccus, Microbacterium, Rothia and Frondihabitans, and the yeast isolates to genera Rhodosporidium, Cryptococcus, Leucosporidiella, Candida and Exophiala. Some ecophysiological properties of isolated strains were determined that are important in response to different stresses such as psychro- and halotolerance, UV-resistance and production of hydrolytic enzymes. The majority of isolates (88 %) was found to be psychrotolerant; all are halotolerant. Significant differences in survival subsequent to UV-C radiation were observed among the isolates, as measured by culturable counts. For the bacterial isolates, lethal doses in the range 80-600 J m⁻² were determined, and for the yeast isolates--in the range 300-1,000 J m⁻². Dermacoccus profundi U9 and Candida davisiana U6 were found as most UV resistant among the bacterial and yeast isolates, respectively. Producers of caseinase, gelatinase, β-glucosidase, and cellulase were detected. To the best of our knowledge, this is the first report on isolation of UV resistant strain D. profundi, and Frondihabitans strain from Antarctica, and on detection of cellulase activity in Antarctic yeast strain C. davisiana. The results obtained contribute to clarifying adaptation strategies of Antarctic microbiota and its possible role in functional stability of Antarctic biocenoses. Stress tolerant strains were detected that are valuable for ecological and applied studies.

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.

A novel psychrotolerant, strictly aerobic, non-motile, rod-shaped bacterial strain, designated IM13 T , was isolated from a sample taken from prehistoric guano paintings in Magura Cave, northwest Bulgaria and subjected to a polyphasic taxonomic study. Strain IM13 T formed yellow colonies on LB agar plates and was Gram-staining-negative, heterotrophic and alkalitolerant. It grew optimally at pH 7.5 and 30 6C in the absence of NaCl. Phylogenetic analysis of the whole 16S rRNA gene revealed that strain IM13 T branched with representatives of the genus Myroides with sequence similarity of 93-94 % with other species of the genus. The novel isolate contained iso-C 15 : 0 (49.1 %), iso-C 17 : 1 v9c (18.2 %) and iso-C 17 : 0 3-OH (14.0 %) as dominant fatty acids. The DNA G+C content of strain IM13 T was 33.5 mol%. Based on phylogenetic inference and phenotypic characteristics, it was concluded that strain IM13 T represents a novel species of the genus Myroides, for which the name Myroides guanonis sp. nov. is proposed. The type strain is IM13 T (5DSM 26542 T 5NBIMCC 8736 T ).

Hot environments are between the supporting life extreme niches that appear to have maintained some degree of pristine quality and of special biotechnological interest. Knowledge on biodiversity in terrestrial hot springs is still scanty and has not been compared in the light of the specificity of those extreme ecological niches. Study on diversity of thermophilic bacteria inhabiting a hot spring located in Rupi Basin (RB), South-West Bulgaria, revealed a high phylogenetic richness in it (genotypic diversity is 0.37). A total of 120 clones were examined, and grouped in 28 phylogenetic types by their RFLP profile. 16S rRNA gene analysis allowed the identification of nine divisions from the domain Bacteria and one Candidate division. Ten of the retrieved bacterial sequences representing one third of the sequence types showed less than 97% similarity to the closest neighbor and were referred as new sequences. Four of them were distantly related to validly described bacteria (showed B90% similarity) suggesting new taxons on at least genus level. Comparison of biodiversity in the spring from Rupi Basin, Bulgaria with that described from other terrestrial hot springs revealed that Proteobacteria, Hydrogenobacter/Aquifex and Thermus are common bacterial groups for terrestrial hot springs. Simultaneously, specific bacterial taxons were observed in different springs.

Zusammenfassung: Patriotischer Nationalstolz (z.B. Stolz auf die Demokratie) übt nach bisherigen Studien - im Gegensatz zu nationalistischem Nationalstolz (z.B. Stolz, Deutsche/r zu sein) - demokratisch erwünschte reduzierende Effekte auf Ethnozentrismus aus. Hier wird angenommen, dass (1) sich patriotischer Stolz auf die drei Komponenten nationale Identifikation, Wichtigkeit demokratischer Aspekte Deutschlands und Glaube an die Realisiertheit demokratischer Aspekte Deutschlands zurückführen lässt und dass (2) diese Komponenten teilweise gegensätzliche Effekte auf Ethnozentrismus und weitere Variablen ausüben. In zwei Fragebogenstudien (N1 = 121, N2 = 150) wird gezeigt, dass (1) die drei genannten Komponenten patriotischen Nationalstolz vorhersagen und (2) die demokratisch erwünschten Effekte des patriotischen Stolzes im Wesentlichen auf die Wichtigkeit demokratischer Aspekte zurückgehen. Es wird gefolgert, dass aus demokratischer Sicht nicht patriotischer Stolz, sondern eine positive Wertschätzung demokratischer Aspekte gefördert werden sollte.