Corynebacterium mendelii sp. nov., a novel bacterium isolated from Adélie penguin oral cavity.

The taxonomic status of strain P5891T, isolated from an Adélie penguin beak swab, was investigated. Based on the 16S rRNA gene sequence, the strain was identified as a potentially novel Corynebacterium species, with the highest sequence similarities to Corynebacterium rouxii FRC0190T (96.7 %) and Corynebacterium epidermidicanis DSM 45586T (96.6 %). The average nucleotide identity values between strain P5891T and C. rouxii FRC0190T and C. epidermidicanis DSM 45586T were 68.2 and 69.2 %, respectively. The digital DNA-DNA hybridization values between strain P5891T and C. rouxii FRC0190T and C. epidermidicanis DSM 45586T were 23.7 and 21.4 %, respectively. Phylogenetic trees based on the 16S rRNA sequence placed strain P5891T in a separate branch with Corynebacterium canis 1170T and Corynebacterium freiburgense 1045T, while a phylogenomic tree based on the Corynebacterium species core genome placed the strain next to Corynebacterium choanae 200CHT. Extensive phenotyping and genomic analyses clearly confirmed that strain P5891T represents a novel species of the genus Corynebacterium, for which the name Corynebacterium mendelii sp. nov. is proposed, with the type strain P5891T (=CCM 8862T=LMG 31627T).

Mechanistic transcriptome comprehension of Chlamydomonas reinhardtii subjected to black phosphorus.

Two-dimensional materials have recently gained significant awareness. A representative of such materials, black phosphorous (BP), earned attention based on its comprehensive application potential. The presented study focuses on the mode of cellular response underlying the BP interaction with Chlamydomonas reinhardtii as an algal model organism. We observed noticeable ROS formation and changes in outer cellular topology after 72 h of incubation at 5 mg/L BP. Transcriptome profiling was employed to examine C. reinhardtii response after exposure to 25 mg/L BP for a deeper understanding of the associated processes. The RNA sequencing has revealed a comprehensive response with abundant transcript downregulation. The mode of action was attributed to cell wall disruption, ROS elevation, and chloroplast disturbance. Besides many other dysregulated genes, the cell response involved the downregulation of GH9 and gametolysin within a cell wall, pointing to a shift to discrete manipulation with resources. The response also included altered expression of the PRDA1 gene associated with redox governance in chloroplasts implying ROS disharmony. Altered expression of the Cre-miR906-3p, Cre-miR910, and Cre-miR914 pointed to those as potential markers in stress response studies.

Proving the automatic benchtop electrochemical station for the development of dopamine and paracetamol sensors.

The introduced work represents an implementation of the automatic benchtop electrochemical station (BES) as an effective tool for the possibilities of high-throughput preparation of modified sensor/biosensors, speeding up the development of the analytical method, and automation of the analytical procedure for the determination of paracetamol (PAR) and dopamine (DOP) as target analytes. Within the preparation of gold nanoparticles modified screen-printed carbon electrode (AuNPs-SPCE) by electrodeposition, the deposition potential EDEP, the deposition time tDEP, and the concentration of HAuCl4 were optimized and their influence was monitored on 1 mM [Ru(NH3)6]3+/2+ redox probe and 50 µM DOP. The morphology of the AuNPs-SPCE prepared at various modification conditions was observed by SEM. The analytical performance of the AuNPs-SPCE prepared at different modification conditions was evaluated by a construction of the calibration curves of DOP and PAR. SPCE and AuNPs-SPCE at modification condition providing the best sensitivity to PAR and DOP, were successfully used to determine PAR and DOP in tap water by "spike-recovery" approach. The BES yields better reproducibility of the preparation of AuNPs-SPCE (RSD = 3.0%) in comparison with the case when AuNPs-SPCE was prepared manually by highly skilled laboratory operator (RSD = 7.0%).

Synthesis and characterization of TiO2 nanoparticles combined with geraniol and their synergistic antibacterial activity.

BACKGROUND: The emergence of antibiotic resistance in pathogenic bacteria has become a global threat, encouraging the adoption of efficient and effective alternatives to conventional antibiotics and promoting their use as replacements. Titanium dioxide nanoparticles (TiO2 NPs) have been reported to exhibit antibacterial properties. In this study, we synthesized and characterized TiO2 NPs in anatase and rutile forms with surface modification by geraniol (GER). RESULTS: The crystallinity and morphology of modified TiO2 NPs were analyzed by UV/Vis spectrophotometry, X-ray powder diffraction (XRD), and scanning electron microscopy (SEM) with elemental mapping (EDS). The antimicrobial activity of TiO2 NPs with geraniol was assessed against Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), and Escherichia coli. The minimum inhibitory concentration (MIC) values of modified NPs ranged from 0.25 to 1.0 mg/ml against all bacterial strains, and the live dead assay and fractional inhibitory concentration (FIC) supported the antibacterial properties of TiO2 NPs with GER. Moreover, TiO2 NPs with GER also showed a significant decrease in the biofilm thickness of MRSA. CONCLUSIONS: Our results suggest that TiO2 NPs with GER offer a promising alternative to antibiotics, particularly for controlling antibiotic-resistant strains. The surface modification of TiO2 NPs by geraniol resulted in enhanced antibacterial properties against multiple bacterial strains, including antibiotic-resistant MRSA. The potential applications of modified TiO2 NPs in the biomedical and environmental fields warrant further investigation.

Synergistic antibacterial action of the iron complex and ampicillin against Staphylococcus aureus.

OBJECTIVES: Resistance to antibiotics among bacteria of clinical importance, including Staphylococcus aureus, is a serious problem worldwide and the search for alternatives is needed. Some metal complexes have antibacterial properties and when combined with antibiotics, they may increase bacterial sensitivity to antimicrobials. In this study, we synthesized the iron complex and tested it in combination with ampicillin (Fe16 + AMP) against S. aureus. METHODS: An iron complex (Fe16) was synthesized and characterized using spectroscopy methods. Confirmation of the synergistic effect between the iron complex (Fe16) and ampicillin (AMP) was performed using ζ-potential, infrared spectra and FICI index calculated from the minimum inhibitory concentration (MIC) from the checkerboard assay. Cytotoxic properties of combination Fe16 + AMP was evaluated on eukaryotic cell line. Impact of combination Fe16 + AMP on chosen genes of S. aureus were performed by Quantitative Real-Time PCR. RESULTS: The MIC of Fe16 + AMP was significantly lower than that of AMP and Fe16 alone. Furthermore, the infrared spectroscopy revealed the change in the ζ-potential of Fe16 + AMP. We demonstrated the ability of Fe16 + AMP to disrupt the bacterial membrane of S. aureus and that likely allowed for better absorption of AMP. In addition, the change in gene expression of bacterial efflux pumps at the sub-inhibitory concentration of AMP suggests an insufficient import of iron into the bacterial cell. At the same time, Fe16 + AMP did not have any cytotoxic effects on keratinocytes. CONCLUSIONS: Combined Fe16 + AMP therapy demonstrated significant synergistic and antimicrobial effects against S. aureus. This study supports the potential of combination therapy and further research.

A color-tunable single-benzene fluorophore-based sensor for sensitive detection of palladium in solution and living cells.

Single-benzene fluorophores are bright and the smallest fluorochromes known so far. In single-benzene fluorophores, the fluorescence is mediated by the push/pull effect of substituting groups. Despite a plethora of advantageous properties, this group of molecules has not been extensively studied for design of high-performance fluorescent sensors of catalytic or enzymatic activities. Thus, herein, new fluorescent probes based on the Tsuji-Trost reaction were developed for the selective detection of palladium and other transition metals (platinum and gold) in an aqueous/organic mixed solvent with the sensitivity down to 2.5 nM (for palladium). The relative flexibility in the synthesis of these probes allows for facile color tuning of the emitted fluorescence. In this study, we have successfully utilized a yellow emission variant for sensitive detection of palladium under cell-free conditions and in living cells, validating its possible applicability for high-throughput optical sensing of catalysts for bioorthogonal chemistry under physiological conditions.

Pedobacter fastidiosus sp. nov., isolated from glacial habitats of maritime Antarctica.

Strains P8930T and 478 were isolated from Antarctic glaciers located on James Ross Island and King George Island, respectively. They comprised Gram-stain-negative short rod-shaped cells forming pink pigmented colonies and exhibited identical 16S rRNA gene sequences and highly similar MALDI TOF mass spectra, and hence were assigned as representatives of the same species. Phylogenetic analysis based on 16S rRNA gene sequences assigned both isolates to the genus Pedobacter and showed Pedobacter frigidisoli and Pedobacter terrae to be their closest phylogenetic neighbours, with 97.4 and 97.2 % 16S rRNA gene sequence similarities, respectively. These low similarity values were below the threshold similarity value of 98.7%, confirming the delineation of a new bacterial species. Further genomic characterization included whole-genome sequencing accompanied by average nucleotide identity (ANI) and digital DNA-DNA hybridization calculations, and characterization of the genome features. The ANI values between P8930T and P. frigidisoli RP-3-11T and P. terrae DSM 17933T were 79.7 and 77.6 %, respectively, and the value between P. frigidisoli RP-3-11T and P. terrae DSM 17933T was 77.7 %, clearly demonstrating the phylogenetic distance and the novelty of strain P8930T. Further characterization included analysis of cellular fatty acids, quinones and polar lipids, and comprehensive biotyping. All the obtained results proved the separation of strains P8930T and 478 from the other validly named Pedobacter species, and confirmed that they represent a new species for which the name Pedobacter fastidiosus sp. nov. is proposed. The type strain is P8930T (=CCM 8938T=LMG 32098T).

Thermo- and ROS-Responsive Self-Assembled Polymer Nanoparticle Tracers for 19F MRI Theranostics.

Fluorine-19 magnetic resonance imaging (19F MRI) enables detailed in vivo tracking of fluorine-containing tracers and is therefore becoming a particularly useful tool in noninvasive medical imaging. In previous studies, we introduced biocompatible polymers based on the hydrophilic monomer N-(2-hydroxypropyl)methacrylamide (HPMA) and the thermoresponsive monomer N-(2,2-difluoroethyl)acrylamide (DFEA). These polymers have abundant magnetically equivalent fluorine atoms and advantageous properties as 19F MRI tracers. Furthermore, in this pilot study, we modified these polymers by introducing a redox-responsive monomer. As a result, our polymers changed their physicochemical properties once exposed to an oxidative environment. Reactive oxygen species (ROS)-responsive polymers were prepared by incorporating small amounts (0.9-4.5 mol %) of the N-[2-(ferrocenylcarboxamido)ethyl]acrylamide (FcCEA) monomer, which is hydrophobic and diamagnetic in the reduced electroneutral (Fe(II), ferrocene) state but hydrophilic and paramagnetic in the oxidized (Fe(III), ferrocenium cation) state. This property can be useful for theranostic purposes (therapy and diagnostic purposes), especially, in terms of ROS-responsive drug-delivery systems. In the reduced state, these nanoparticles remain self-assembled with the encapsulated drug but release the drug upon oxidation in ROS-rich tumors or inflamed tissues.

Pseudomonas leptonychotis sp. nov., isolated from Weddell seals in Antarctica.

A taxonomic study was carried out on four Gram-stain-negative strains P5773T, P6169, P4708 and P6245, isolated from anus or mouth samples of Weddell seals at James Ross Island, Antarctica. The results of initial 16S rRNA gene sequence analysis showed that all four strains formed a group placed in the genus Pseudomonas and found Pseudomonas guineae and Pseudomonas peli to be their closest neighbours with 99.9 and 99.2 % sequence similarity, respectively. Sequence analysis of rpoD, rpoB and gyrB housekeeping genes confirmed the highest similarity of isolates to P. peli (rpoD) and to P. guineae (rpoB and gyrB). The average nucleotide identity value below 86 %, as calculated from the whole-genome sequence data, showed the low genomic relatedness of P5773T to its phylogenetic neighbours. The complete genome of strain P5773T was 4.4 Mb long and contained genes encoding proteins with biotechnological potential. The major fatty acids of the seal isolates were summed feature 8 (C18 : 1 ω7c), summed feature 3 (C16 : 1 ω 7 c/C16  : 1 ω6c) and C16:0. The major respiratory quinone was Q9. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. Putrescine and spermidine are predominant in the polyamine pattern. Further characterization performed using repetitive sequence-based PCR fingerprinting and MALDI-TOF MS analysis showed that the studied isolates formed a coherent cluster separated from the remaining Pseudomonas species and confirmed that they represent a novel species within the genus Pseudomonas, for which the name Pseudomonas leptonychotis sp. nov. is suggested. The type strain is P5773T (=CCM 8849T=LMG 30618T).

Pseudomonas karstica sp. nov. and Pseudomonas spelaei sp. nov., isolated from calcite moonmilk deposits from caves.

A taxonomic study of two fluorescent Pseudomonas strains (HJ/4T and SJ/9/1T) isolated from calcite moonmilk samples obtained from two caves in the Moravian Karst in the Czech Republic was carried out. Results of initial 16S rRNA gene sequence analysis assigned both strains into the genus Pseudomonas and showed Pseudomonas yamanorum 8H1T as their closest neighbour with 99.8 and 99.7 % 16S rRNA gene similarities to strains HJ/4T and SJ/9/1T, respectively. Subsequent sequence analysis of rpoD, rpoB and gyrB housekeeping genes confirmed the highest similarity of both isolates to P. yamanorum 8H1T, but phylogeny and sequences similarities implied that they are representatives of two novel species within the genus Pseudomonas. Further study comprising whole-genome sequencing followed by average nucleotide identity and digital DNA-DNA hybridization calculations, repetitive sequence-based PCR fingerprinting with the REP and ERIC primers, automated ribotyping with the EcoRI restriction endonuclease, cellular fatty acid analysis, quinone and polar lipid characterization, and extensive biotyping confirmed clear separation of both analysed strains from the remaining Pseudomonas species and showed that they represent two novel species within the genus Pseudomonas for which the names Pseudomonas karstica sp. nov. (type strain HJ/4T=CCM 7891T=LMG 27930T) and Pseudomonas spelaei sp. nov. (type strain SJ/9/1T=CCM 7893T=LMG 27931T) are suggested.

Hymenobacter terrestris sp. nov. and Hymenobacter lapidiphilus sp. nov., isolated from regoliths in Antarctica.

A group of four psychrotrophic bacterial strains was isolated on James Ross Island (Antarctica) in 2013. All isolates, originating from different soil samples, were collected from the ice-free northern part of the island. They were rod-shaped, Gram-stain-negative, and produced moderately slimy red-pink pigmented colonies on R2A agar. A polyphasic taxonomic approach based on 16S rRNA gene sequencing, whole-genome sequencing, MALDI-TOF MS, rep-PCR analyses, chemotaxonomic methods and extensive biotyping was used to clarify the taxonomic position of these isolates. Phylogenetic analysis based on 16S rRNA gene sequences showed that the isolates belonged to the genus Hymenobacter. The closest relative was Hymenobacter humicola CCM 8763T, exhibiting 98.3 and 98.9% 16S rRNA pairwise similarity with the reference isolates P5342T and P5252T, respectively. Average nucleotide identity, digital DNA-DNA hybridization and core gene distances calculated from the whole-genome sequencing data confirmed that P5252T and P5342T represent two distinct Hymenobacter species. The menaquinone systems of both strains contained MK-7 as the major respiratory quinone. The predominant polar lipids for both strains were phosphatidylethanolamine and one unidentified glycolipid. The major components in the cellular fatty acid composition were summed feature 3 (C16:1 ω7c/C16:1ω6c), C16:1ω5c, summed feature 4 (anteiso-C17:1 B/iso-C17:1 I), anteiso-C15:0 and iso-C15 : 0 for all isolates. Based on the obtained results, two novel species are proposed, for which the names Hymenobacter terrestris sp. nov. (type strain P5252T=CCM 8765T=LMG 31495T) and Hymenobacter lapidiphilus sp. nov. (type strain P5342T=CCM 8764T=LMG 30613T) are suggested.

Staphylococcus petrasii diagnostics and its pathogenic potential enhanced by mobile genetic elements.

Staphylococcus petrasii is recently described coagulase negative staphylococcal species and an opportunistic human pathogen, still often misidentified in clinical specimens. Four subspecies are distinguished in S. petrasii by polyphasic taxonomical analyses, however a comparative study has still not been done on the majority of isolates and their genome properties have not yet been thoroughly analysed. Here, we describe the phenotypic and genotypic characteristics of 65 isolates and the results of de novo sequencing, whole genome assembly and annotation of draft genomes of five strains. The strains were identified by MALDI-TOF mass spectrometry to the species level and the majority of the strains were identified to the subspecies level by fingerprinting methods, (GTG)5 repetitive PCR and ribotyping. Macrorestriction profiling by pulsed-field gel electrophoresis was confirmed to be a suitable strain typing method. Comparative genomics revealed the presence of new mobile genetic elements carrying antimicrobial resistance factors such as staphylococcal cassette chromosome (SCC) mec, transposones, phage-inducible genomic islands, and plasmids. Their mosaic structure and similarity across coagulase-negative staphylococci and Staphylococcus aureus suggest the possible exchange of these elements. Numerous putative virulence factors such as adhesins, autolysins, exoenzymes, capsule formation genes, immunomodulators, the phage-associated sasX gene, and SCC-associated spermidine N-acetyltransferase gene, pseudouridine and sorbitol utilization operons might explain clinical manifestations of S. petrasii isolates. The increasing recovery of S. petrasii isolates from human clinical material, the multi-drug resistance including methicillin resistance of S. petrasii subsp. jettensis strains, and virulence factors homologous to other pathogenic staphylococci demonstrate the importance of the species in human disease.

Pseudogemmobacter bohemicus gen. nov., sp. nov., a novel taxon from the Rhodobacteraceae family isolated from heavy-metal-contaminated sludge.

The creamy white to beige, aerobic, non-motile, ovoid to rod-shaped, Gram-stain-negative strain, Cd-10T, was isolated from heavy-metal-contaminated sludge from a decantation basin of a heavy metal processing factory based on its ability to tolerate CdCl2 in the cultivation medium. In the reconstruction of its phylogeny based on 16S rRNA gene sequences, strain Cd-10T clustered with species of the genera Gemmobacter, Xinfangfangia, Tabrizicola and Rhodobacter within the family Rhodobacteraceae. Its 16S rRNA gene sequence exhibited 96.32 % pairwise similarity to the type strain of Xinfangfangia soli, 95.3 % to that of Gemmobacter intermedius, followed by Tabrizicola fusiformis (95.10 %), Rhodobacter sediminis (94.88 %), Gemmobacter nectariphilus and Rhodobacter capsulatus (both 94.81 %). The major respiratory quinone was Q-10 accompanied by Q-9, the fatty acid profile consisted predominantly of C18 : 1ω7c, C18 : 0, C16 : 0 and C16 : 1ω7c, the major polar lipids were phosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylcholine and diphosphatidylglycerol. An analysis of the percentage of conserved proteins deduced from draft or complete genomic sequences of strain Cd-10T and representatives of its closest relatives suggested that strain Cd-10T is a member of a novel genus within the Rhodobacteraceae family for which we propose the name Pseudogemmobacter. Strain Cd-10T (=DSM 103618T=NCCB 100645T) is the type strain of Pseudogemmobacter bohemicus gen. nov., sp. nov., the type species of the genus Pseudogemmobacter gen. nov.

Hymenobacter humicola sp. nov., isolated from soils in Antarctica.

A set of three psychrotrophic bacterial strains was isolated from different soil samples collected at the deglaciated northern part of James Ross Island (Antarctica) in 2014. All isolates were rod-shaped, Gram-stain-negative, non-motile, catalase-positive and oxidase-negative, and produced moderately slimy red-pink pigmented colonies on Reasoner's 2A (R2A) agar. A polyphasic taxonomic approach based on 16S rRNA gene sequencing, whole-genome sequencing, automated ribotyping, MALDI-TOF MS, chemotaxonomy methods and extensive biotyping using conventional tests and commercial identification kits was applied to the isolates in order to clarify their taxonomic position. Phylogenetic analysis based on the 16S rRNA gene showed that all isolates belonged to the genus Hymenobacter with the closest relative being Hymenobacter aerophilus DSM 13606T, exhibiting 98.5 % 16S rRNA gene pairwise similarity to the reference isolate P6312T. Average nucleotide identity values calculated from the whole-genome sequencing data proved that P6312T represents a distinct Hymenobacter species. The major components of the cellular fatty acid composition were summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c), C16 : 1 ω5c, summed feature 4 (C17 : 1 anteiso B/iso I), C15 : 0 anteiso and C15 : 0 iso. The menaquinone system of strain P6312T contained MK-7 as the major respiratory quinone. The predominant polar lipids were phosphatidylethanolamine and an unidentified phospholipid. Moderate to minor amounts of three unidentified polar lipids, four unidentified aminophospholipids, one unidentified glycolipid and one unidentified phospholipid were also present. Based on the obtained results, we propose a novel species for which the name Hymenobacterhumicola sp. nov. is suggested, with the type strain P6312T (=CCM 8763T=LMG 30612T).

Staphylococcus edaphicus sp. nov., Isolated in Antarctica, Harbors the mecC Gene and Genomic Islands with a Suspected Role in Adaptation to Extreme Environments.

Two Gram-stain-positive, coagulase-negative staphylococcal strains were isolated from abiotic sources comprising stone fragments and sandy soil in James Ross Island, Antarctica. Here, we describe properties of a novel species of the genus Staphylococcus that has a 16S rRNA gene sequence nearly identical to that of Staphylococcus saprophyticus However, compared to S. saprophyticus and the next closest relatives, the new species demonstrates considerable phylogenetic distance at the whole-genome level, with an average nucleotide identity of <85% and inferred DNA-DNA hybridization of <30%. It forms a separate branch in the S. saprophyticus phylogenetic clade as confirmed by multilocus sequence analysis of six housekeeping genes, rpoB, hsp60, tuf, dnaJ, gap, and sod Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and key biochemical characteristics allowed these bacteria to be distinguished from their nearest phylogenetic neighbors. In contrast to S. saprophyticus subsp. saprophyticus, the novel strains are pyrrolidonyl arylamidase and ß-glucuronidase positive and ß-galactosidase negative, nitrate is reduced, and acid produced aerobically from d-mannose. Whole-genome sequencing of the 2.69-Mb large chromosome revealed the presence of a number of mobile genetic elements, including the 27-kb pseudo-staphylococcus cassette chromosome mec of strain P5085T (ψSCCmecP5085), harboring the mecC gene, two composite phage-inducible chromosomal islands probably essential to adaptation to extreme environments, and one complete and one defective prophage. Both strains are resistant to penicillin G, ampicillin, ceftazidime, methicillin, cefoxitin, and fosfomycin. We hypothesize that antibiotic resistance might represent an evolutionary advantage against beta-lactam producers, which are common in a polar environment. Based on these results, a novel species of the genus Staphylococcus is described and named Staphylococcus edaphicus sp. nov. The type strain is P5085T (= CCM 8730T = DSM 104441T).IMPORTANCE The description of Staphylococcus edaphicus sp. nov. enables the comparison of multidrug-resistant staphylococci from human and veterinary sources evolved in the globalized world to their geographically distant relative from the extreme Antarctic environment. Although this new species was not exposed to the pressure of antibiotic treatment in human or veterinary practice, mobile genetic elements carrying antimicrobial resistance genes were found in the genome. The genomic characteristics presented here elucidate the evolutionary relationships in the Staphylococcus genus with a special focus on antimicrobial resistance, pathogenicity, and survival traits. Genes encoded on mobile genetic elements were arranged in unique combinations but retained conserved locations for the integration of mobile genetic elements. These findings point to enormous plasticity of the staphylococcal pangenome, shaped by horizontal gene transfer. Thus, S. edaphicus can act not only as a reservoir of antibiotic resistance in a natural environment but also as a mediator for the spread and evolution of resistance genes.

Flavobacterium chryseum sp. nov. and Flavobacterium psychroterrae sp. nov., novel environmental bacteria isolated from Antarctica.

A group of rod-shaped, aerobic, Gram-stain-negative, gliding bacteria producing flexirubin-type pigment was isolated from environmental samples collected in Antarctica in 2009-2014. Phylogenetic analysis of the almost complete 16S rRNA gene sequences revealed two separated branches belonging to the genus Flavobacterium. Group I (n=8), represented by strain CCM 8826T, shared the highest sequence similarity to Flavobacterium collinsii 983-08T (98.8 %) and Flavobacterium saccharophilum DSM 1811T (98.4 %), and group II (n=4) represented by strain CCM 8827T shared the highest similarity to Flavobacterium aquidurense WB 1.1-56T (99.6 %). High genetic homogeneity of both groups, separation from each other and from phylogenetically close Flavobacterium species was verified by the rep-PCR fingerprinting method. DNA-DNA hybridization confirmed low genomic relatedness between strain CCM 8826T and F. collinsii 983-08T and F. saccharophilum DSM 1811T (18 and 28 %, respectively) and between strain CCM 8827T and F. aquidurense WB 1.1-56T (27 %). Chemotaxonomic analyses of strains CCM 8826T and CCM 8827T revealed the respiratory quinone to be MK-6, the major identified polar lipid was phosphatidylethanolamine and the predominant polyamine was sym-homospermidine. The common major fatty acids were C15 : 0 iso, C17 : 0 iso 3OH, C15 : 1 iso G, Summed Feature 3 (C16 : 1ω7c/C16 : 1ω6c), C15 : 0 iso 3OH and additionally, C15 : 0 anteiso among group II members. All analyses confirmed that strains of group I and II represent two novel species of the genus Flavobacterium, for which the names Flavobacterium chryseum sp. nov. (type strain CCM 8826T=P3160T=LMG 30615T) and Flavobacterium psychroterrae sp. nov. (type strain CCM 8827T=P3922T=LMG 30616T) are proposed.

Lactobacillus caviae sp. nov., an obligately heterofermentative bacterium isolated from the oral cavity of a guinea pig (Cavia aperea f. porcellus).

A Gram-stain-positive, facultatively anaerobic, and catalase- and oxidase-negative bacterial strain designated MOZM2T, having 98.4 % 16S rRNA gene sequence identity with Lactobacillus reuteri DSM 20016T, was isolated from a swab of the oral cavity of a home-bred guinea pig. Comparative analyses based on the hsp60, pheS and tuf genes confirmed L. reuteri as its closest relative species, with calculated sequence similarities of 92.8, 88.8 and 96.9 %, respectively. DNA-DNA hybridisation revealed a 42 % degree of genetic similarity between the novel strain and L. reuteri DSM 20016T. Strain MOZM2T degrades carbohydrates via the 6-phosphogluconate/phosphoketolase pathway, evidenced by its production of gas from glucose and the end products of hexose catabolism. Comparative analysis of the cellular fatty acid profiles determined significant differences between MOZM2T and L. reuteri DSM 20016T in their proportions of C8 : 0, C14 : 1, C17 : 0, C18 : 2ω6t and C20 : 0 fatty acids. Results of genotypic analyses also demonstrated differences between these two strains. They also differed in DNA G+C content, and some biochemical and physiological characteristics. We therefore believe that the examined bacterial isolate should be considered as a new taxon within the group of obligately heterofermentative lactobacilli. The species name Lactobacillus caviae sp. nov. is proposed, of which the type strain is MOZM2T (=CCM 8609T=DSM 100239T=LMG 28780T).

Pedobacter psychrophilus sp. nov., isolated from fragmentary rock.

Strain P4487AT was isolated during investigation of cultivable bacterial populations of environmental materials sampled at James Ross Island, Antarctica. It revealed Gram-stain-negative short rod-shaped cells producing a pink pigment. Phylogenetic analysis based on 16S rRNA gene sequences allocated strain P4487AT to the genus Pedobacter but showed that the strain represents a distinct intrageneric phylogenetic lineage clearly separated from remaining Pedobacter species. Phylogenetically, strain P4487AT formed a common branch with the Pedobacter arcticus and Pedobacter lignilitoris cluster while the highest value of 94.4 % 16S rRNA gene sequence similarity suggested that Pedobacter lentus is the most closely related species. Biochemical and physiological test results enabled the differentiation of strain P4487AT from all phylogenetically closely related species. Chemotaxonomic analyses of strain P4487AT showed MK-7 as the respiratory menaquinone, sym-homospermidine as the major polyamine, phosphatidylethanolamine and two unidentified lipids as the major polar lipids, presence of sphingolipids, and C16 : 1ω7c/C16 : 1ω6c (summed feature 3), iso-C15 : 0 and iso-C17 : 0 3-OH as the major fatty acids, all of which corresponded with characteristics of the genus Pedobacter. The results showed that strain P4487AT represents a novel species within the genus Pedobacter, for which the name Pedobacter psychrophilus sp. nov. is proposed. The type strain is P4487AT (=CCM 8644T=LMG 29436T).

Mucilaginibacter terrae sp. nov., isolated from Antarctic soil.

A bacterial strain designated CCM 8645T was isolated from a soil sample collected nearby a mummified seal carcass in the northern part of James Ross Island, Antarctica. The cells were short rods, Gram-stain-negative, non-motile, catalase and oxidase positive, and produced a red-pink pigment on R2A agar. A polyphasic taxonomic approach based on 16S rRNA gene sequencing, extensive biotyping using conventional tests and commercial identification kits and chemotaxonomic analyses were applied to clarify its taxonomic position. Phylogenetic analysis based on the 16S rRNA gene placed strain CCM 8645T in the genus Mucilaginibacter with the closest relative being Mucilaginibacter daejeonensis Jip 10T, exhibiting 96.5 % 16S rRNA pairwise similarity which was clearly below the 97 % threshold value recommended for species demarcation. The major components in fatty acid profiles were Summed feature 3 (C16 : 1ω7c/C16 : 1ω6c), C15 : 0 iso and C17 : 0 iso 3OH. The cellular quinone content was exclusively menaquinone MK-7. The major polyamine was sym-homospermidine and predominant polar lipids were phosphatidylethanolamine and phosphatidylserine. Based on presented results, we propose a novel species for which the name Mucilaginibacter terrae sp. nov. is suggested, with the type strain CCM 8645T (=LMG 29437T).

Red-pink pigmented Hymenobacter coccineus sp. nov., Hymenobacter lapidarius sp. nov. and Hymenobacter glacialis sp. nov., isolated from rocks in Antarctica.

Four rod-shaped and Gram-stain-negative bacterial strains, CCM 8647, CCM 8649T, CCM 8643T and CCM 8648T, were isolated from rock samples collected on James Ross Island, Antarctica. Extensive biotyping, fatty acid profiling, chemotaxonomy, 16S rRNA gene sequencing and whole-genome sequencing was applied to isolates to clarify their taxonomic position. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that all four isolates belonged to the genus Hymenobacter. Strains CCM 8649T and CCM 8647 were most closely related to Hymenobacter arizonensis OR362-8T (94.4 % 16S rRNA gene sequence similarity), strain CCM 8643T to Hymenobacter terrae DG7AT (96.3 %) and strain CCM 8648T to Hymenobacter glaciei VUG-A130T (96.3 %). The predominant fatty acids of CCM 8649T and CCM 8647 were summed feature 3 (C16 : 1ω7c/C16 : 1ω6c), C16 : 1ω5c and iso-C15 : 0, whereas those of CCM 8643T and CCM 8648T were summed feature 3 (C16 : 1ω7c/C16 : 1ω6c) and C16 : 1ω5c. The quinone systems contained exclusively menaquinone MK-7. The major polyamine was sym-homospermidine. All four strains contained the major polar lipid phosphatidylethanolamine. The G+C content of genomic DNA ranged from 60-63 mol%. Whole-genome sequencing data supported the finding that isolates represented distinct species of the genus Hymenobacter. On the basis of the results obtained, three novel species are proposed for which the names Hymenobacter coccineus sp. nov., Hymenobacter lapidarius sp. nov. and Hymenobacter glacialis sp. nov. are suggested, with the type strains CCM 8649T (=LMG 29441T=P5239T), CCM 8643T (=LMG 29435T=P3150T) and CCM 8648T (=LMG 29440T=P5086T), respectively.