An aerobic, Gram-stain-positive and non-spore-forming strain, designated C1-1T, was isolated from a fellfield soil sample collected from frost-sorted polygons on Jane Col, Signy Island, Maritime Antarctic. Cells with a size of 0.65-0.9×1.2-1.7 µm have a flagellar motile apparatus and exhibit a rod-coccus growth cycle. Optimal growth conditions were observed at 15-20 °C, pH 7.0 and NaCl concentration up to 0.5 % (w/v) in the medium. The 16S rRNA gene sequence of C1-1T showed the highest pairwise similarity of 98.77 % to Arthrobacter glacialis NBRC 113092T. Phylogenetic trees based on the 16S rRNA and whole-genome sequences revealed that strain C1-1T belongs to the genus Arthrobacter and is most closely related to members of the 'Arthrobacter psychrolactophilus group'. The G+C content of genomic DNA was 58.95 mol%. The original and orthologous average nucleotide identities between strain C1-1T and A. glacialis NBRC 113092T were 77.15 % and 77.38 %, respectively. The digital DNA-DNA relatedness values between strain C1-1T and A. glacialis NBRC 113092T was 21.6 %. The polar lipid profile was composed mainly of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and an unidentified glycolipid. The predominant cellular fatty acids were anteiso-C15 : 0 (75 %) and anteiso-C17 : 0 (15.2 %). Menaquinone MK-9(H2) (86.4 %) was the major respiratory quinone in strain C1-1T. The peptidoglycan type was determined as A3α (l-Lys-l-Ala3; A11.6). Based on all described phylogenetic, physiological and chemotaxonomic characteristics, we propose that strain C1-1T (=DSM 112353T=CCM 9148T) is the type strain of a novel species Arthrobacter polaris sp. nov.

• Klíčová slova
• Antarctica, Arthrobacter, Micrococcaceae, cold-adapted microorganisms, whole-genome sequencing,
• MeSH
• Arthrobacter * MeSH
• chlorid sodný MeSH
• DNA bakterií genetika   MeSH
• fosfatidylinositoly MeSH
• fosfolipidy chemie   MeSH
• fylogeneze MeSH
• glykolipidy chemie   MeSH
• hybridizace nukleových kyselin MeSH
• kardiolipiny MeSH
• mastné kyseliny chemie   MeSH
• Micrococcaceae * MeSH
• nukleotidy MeSH
• peptidoglykan chemie   MeSH
• půda MeSH
• RNA ribozomální 16S genetika   MeSH
• sekvenční analýza DNA MeSH
• techniky typizace bakterií MeSH
• vitamin K 2 chemie   MeSH
• zastoupení bazí MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Antarktida MeSH
• Názvy látek
• chlorid sodný MeSH
• DNA bakterií MeSH
• fosfatidylinositoly MeSH
• fosfolipidy MeSH
• glykolipidy MeSH
• kardiolipiny MeSH
• mastné kyseliny MeSH
• menaquinone 9 MeSH Prohlížeč
• nukleotidy MeSH
• peptidoglykan MeSH
• půda MeSH
• RNA ribozomální 16S MeSH
• vitamin K 2 MeSH

The study of bacterial degradation of 1-octylpyrrolidin-2-one (NOP) by river water and soil bacteria was the main aim of the research. Although the compound demonstrated bacteriostatic as well as bactericidal effects against Gram-positive and certain Gram-negative bacteria at concentrations ranging from 100 to 1000 mg L-1, its concentration of 100 mg L-1 was successfully degraded by microbial communities of both river water and alluvial soil; removal efficiencies reached 87.2 and 88.4% of dissolved organic carbon, respectively. Isolation of the strains responsible for the process showed that bacterial degradation was initiated by the octane-utilising bacteria of the genus Phenylobacterium, which used four carbon atoms of the NOP octyl chain and oxidised terminal carbon atom of the remaining chain. The structure of the intermediate produced by phenylobacteria was elucidated following the results obtained from the detailed electrospray mass spectrometry (ESI-MS) analysis; these experiments showed that it is a 4-(2-oxopyrrolidin-1-yl)butanoic acid. This intermediate was further degraded by other bacterial members of appropriate microbial communities, namely Bordetella petrii and Arthrobacter sp. Further tests proved that these bacteria were able to assimilate the nitrogen atom of the lactam ring and thus complete the degradation process.

• Klíčová slova
• 1-Octylpyrrolidin-2-one, Bacteria, Biodegradation, Intermediate, Isolation,
• MeSH
• antibakteriální látky metabolismus   farmakologie   MeSH
• Arthrobacter * metabolismus   MeSH
• biodegradace MeSH
• půda * chemie   MeSH
• půdní mikrobiologie MeSH
• řeky chemie   MeSH
• uhlík metabolismus   MeSH
• voda metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antibakteriální látky MeSH
• půda * MeSH
• uhlík MeSH
• voda MeSH

The pine engraver beetle, Ips acuminatus Gyll, is a bark beetle that causes important damages in Scots pine (Pinus sylvestris) forests and plantations. As almost all higher organisms, Ips acuminatus harbours a microbiome, although the role of most members of its microbiome is not well understood. As part of a work in which we analysed the bacterial diversity associated to Ips acuminatus, we isolated the strain Arthrobacter sp. IA7. In order to study its potential role within the bark beetle holobiont, we sequenced and explored its genome and performed a pan-genome analysis of the genus Arthrobacter, showing specific genes of strain IA7 that might be related with its particular role in its niche. Based on these investigations, we suggest several potential roles of the bacterium within the beetle. Analysis of genes related to secondary metabolism indicated potential antifungal capability, confirmed by the inhibition of several entomopathogenic fungal strains (Metarhizium anisopliae CCF0966, Lecanicillium muscarium CCF6041, L. muscarium CCF3297, Isaria fumosorosea CCF4401, I. farinosa CCF4808, Beauveria bassiana CCF4422 and B. brongniartii CCF1547). Phylogenetic analyses of the 16S rRNA gene, six concatenated housekeeping genes (tuf-secY-rpoB-recA-fusA-atpD) and genome sequences indicated that strain IA7 is closely related to A. globiformis NBRC 12137T but forms a new species within the genus Arthrobacter; this was confirmed by digital DNA-DNA hybridization (37.10%) and average nucleotide identity (ANIb) (88.9%). Based on phenotypic and genotypic features, we propose strain IA7T as the novel species Arthrobacter ipsi sp. nov. (type strain IA7T = CECT 30100T = LMG 31782T) and suggest its protective role for its host.

• Klíčová slova
• Allelopathic interactions, Beetle protection, Fungal inhibition, Ips microbiota, Microbiome, Pan-genome analysis,
• MeSH
• antibióza MeSH
• Arthrobacter klasifikace   genetika   fyziologie   MeSH
• bakteriální geny genetika   MeSH
• borovice parazitologie   MeSH
• brouci mikrobiologie   MeSH
• DNA bakterií genetika   MeSH
• fenotyp MeSH
• fylogeneze MeSH
• genom bakteriální genetika   MeSH
• houby růst a vývoj   MeSH
• interakce mikroorganismu a hostitele MeSH
• kůra rostlin parazitologie   MeSH
• nemoci rostlin parazitologie   MeSH
• RNA ribozomální 16S genetika   MeSH
• sekvenční analýza DNA MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• DNA bakterií MeSH
• RNA ribozomální 16S MeSH

Bacteria have developed different intra- and inter-specific communication mechanisms that involve the production, release, and detection of signaling molecules, because these molecules serve as the autoinducers involved in "quorum sensing" systems. Other communication mechanisms employ volatile signaling molecules that regulate different bacterial processes. The Arthrobacter agilis strain UMCV2 is a plant growth promoting actinobacterium, which induces plant growth and inhibits phytopathogenic fungi by emitting the dimethylhexadecylamine (DMHDA). However, little is known about the effect of this volatile compound on A. agilis UMCV2 itself, as well as on other bacteria. By exposing A. agilis UMCV2 and bacteria of the genus Bacillus and Pseudomonas to different concentrations of DMHDA, this study showed the dose-dependent effects of DMHDA on A. agilis UMCV2 growth, cellular viability, swarming motility, and expression of marker genes of the flagellar apparatus of bacteria. DMHDA was found to also modulate swarming motility of Bacillus sp. ZAP018 and P. fluorescens UM270, but not that of P. aeruginosa PA01. These data indicate that DMHDA is involved in both intra- and inter-specific bacterial interaction.

• MeSH
• Arthrobacter účinky léků   růst a vývoj   MeSH
• Bacillus účinky léků   růst a vývoj   MeSH
• methylaminy farmakologie   MeSH
• mikrobiální interakce účinky léků   MeSH
• pohyb účinky léků   MeSH
• Pseudomonas účinky léků   růst a vývoj   MeSH
• quorum sensing účinky léků   MeSH
• těkavé organické sloučeniny farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• hexadecyldimethylamine MeSH Prohlížeč
• methylaminy MeSH
• těkavé organické sloučeniny MeSH

The contact assay measuring the inhibition of Arthrobacter globiformis dehydrogenase activity as an endpoint to evaluate the toxicity of solid samples was tested in an international ring-test to validate its performance for ISO standardization (ISO/CD 18187). This work reports the results of the ring-test involving 9 laboratories from six countries. At least 8 valid data sets were obtained for each sample and more than three quarters of the participants attained the validity criteria defined in the standard. The coefficient of variation within (CVr) and between (CVR) laboratories was generally on average <15% and <30% for negative and positive controls, respectively. Regarding solid samples, the laboratories provided a similar ranking of the samples based on their toxicity, despite some variation in the LOEC values. The logarithmic within-lab standard deviation <0.50 for soils and <0.25 for wastes evidenced a good repeatability. The between-lab variability assessed by a CVR <30%, minimum-maximum factor <4 and a reproducibility standard deviation (SDR) <0.13 for a great part of the solid samples, confirmed the test reproducibility. Overall, this assay proved to be robust, sensitive and feasible for routine use towards the quality assessment of soils and wastes.

• Klíčová slova
• Arthrobacter globiformis, Dehydrogenase activity, ISO 18187, Soils, Wastes,
• MeSH
• Arthrobacter enzymologie   MeSH
• biotest * MeSH
• dřevo analýza   MeSH
• geologické sedimenty analýza   MeSH
• hornictví MeSH
• hydrolasy metabolismus   MeSH
• laboratoře MeSH
• látky znečišťující půdu analýza   MeSH
• monitorování životního prostředí MeSH
• popel uhelný analýza   MeSH
• průmyslový odpad analýza   MeSH
• reprodukovatelnost výsledků MeSH
• sklo analýza   MeSH
• těžké kovy analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• hydrolasy MeSH
• látky znečišťující půdu MeSH
• popel uhelný MeSH
• průmyslový odpad MeSH
• těžké kovy MeSH

This study was aimed at complex characterization of three soil samples (bulk soil, topsoil and rhizosphere soil) from a site historically contaminated with polychlorinated biphenyls (PCB). The bulk soil was the most highly contaminated, with a PCB concentration of 705.95 mg kg(-1), while the rhizosphere soil was the least contaminated (169.36 mg kg(-1)). PCB degradation intermediates, namely chlorobenzoic acids (CBAs), were detected in all the soil samples, suggesting the occurrence of microbial transformation processes over time. The higher content of organic carbon in the topsoil and rhizosphere soil than in the bulk soil could be linked to the reduced bioaccessibility (bioavailability) of these chlorinated pollutants. However, different proportions of the PCB congener contents and different bioaccessibility of the PCB homologues indicate microbial biotransformation of the compounds. The higher content of organic carbon probably also promoted the growth of microorganisms, as revealed by phospholipid fatty acid (PFLA) quantification. Tag-encoded pyrosequencing analysis showed that the bacterial community structure was significantly similar among the three soils and was predominated by Proteobacteria (44-48%) in all cases. Moreover, analysis at lower taxonomic levels pointed to the presence of genera (Sphingomonas, Bulkholderia, Arthrobacter, Bacillus) including members with reported PCB removal abilities. The fungal community was mostly represented by Basidiomycota and Ascomycota, which accounted for >80% of all the sequences detected in the three soils. Fungal taxa with biodegradation potential (Paxillus, Cryptococcus, Phoma, Mortierella) were also found. These results highlight the potential of the indigenous consortia present at the site as a starting point for PCB bioremediation processes.

• Klíčová slova
• Bioaccessibility, Bioavailability, Bioremediation, Chlorobenzoic acids, Microbial communities, Polychlorinated biphenyls,
• MeSH
• Arthrobacter MeSH
• biodegradace MeSH
• látky znečišťující půdu analýza   MeSH
• monitorování životního prostředí * MeSH
• polychlorované bifenyly analýza   MeSH
• půda chemie   MeSH
• půdní mikrobiologie * MeSH
• rhizosféra MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• látky znečišťující půdu MeSH
• polychlorované bifenyly MeSH
• půda MeSH

The catalytic reaction of copper amine oxidase proceeds through a ping-pong mechanism comprising two half-reactions. In the initial half-reaction, the substrate amine reduces the Tyr-derived cofactor, topa quinone (TPQ), to an aminoresorcinol form (TPQamr) that is in equilibrium with a semiquinone radical (TPQsq) via an intramolecular electron transfer to the active-site copper. We have analyzed this reductive half-reaction in crystals of the copper amine oxidase from Arthrobacter globiformis. Anerobic soaking of the crystals with an amine substrate shifted the equilibrium toward TPQsq in an "on-copper" conformation, in which the 4-OH group ligated axially to the copper center, which was probably reduced to Cu(I). When the crystals were soaked with substrate in the presence of halide ions, which act as uncompetitive and noncompetitive inhibitors with respect to the amine substrate and dioxygen, respectively, the equilibrium in the crystals shifted toward the "off-copper" conformation of TPQamr. The halide ion was bound to the axial position of the copper center, thereby preventing TPQamr from adopting the on-copper conformation. Furthermore, transient kinetic analyses in the presence of viscogen (glycerol) revealed that only the rate constant in the step of TPQamr/TPQsq interconversion is markedly affected by the viscogen, which probably perturbs the conformational change. These findings unequivocally demonstrate that TPQ undergoes large conformational changes during the reductive half-reaction.

• Klíčová slova
• catalytic intermediate, catalytic mechanism, conformational change, copper amine oxidase, electron transfer, oxidase, quinone, radical, topa quinone, x-ray crystallography,
• MeSH
• Arthrobacter enzymologie   MeSH
• bakteriální proteiny chemie   MeSH
• histaminasa chemie   MeSH
• krystalografie rentgenová MeSH
• měď chemie   MeSH
• terciární struktura proteinů MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bakteriální proteiny MeSH
• histaminasa MeSH
• měď MeSH

Degradation of chlorobenzoic acids (e.g., products of microbial degradation of PCB) by strains of microorganisms isolated from PCB contaminated soils was assessed. From seven bulk-soil isolates two strains unique in ability to degrade a wider range of chlorobenzoic acids than others were selected, individually and even in a complex mixture of 11 different chlorobenzoic acids. Such a feature is lacking in most tested degraders. To investigate the influence of vegetation on chlorobenzoic acids degraders, root exudates of two plant species known for supporting PCB degradation in soil were tested. While with individual chlorobenzoic acids the presence of plant exudates leads to a decrease of degradation yield, in case of a mixture of chlorobenzoic acids either a change in bacterial degradation specificity, associated with 3- and 4-chlorobenzoic acid, or an extension of the spectrum of degraded chlorobenzoic acids was observed.

• MeSH
• Arthrobacter izolace a purifikace   metabolismus   MeSH
• biodegradace účinky léků   MeSH
• chlorbenzoáty metabolismus   MeSH
• kořeny rostlin chemie   MeSH
• Pseudomonas izolace a purifikace   metabolismus   MeSH
• rostlinné extrakty farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chlorbenzoáty MeSH
• rostlinné extrakty MeSH

A microtiter plate-based assay was developed for the automatic monitoring of degradation profile of the yellow-coloured nitrophenolic compounds. The method enables to reduce the intervals between measurements of substrate concentration to minutes and to overcome the problem of discontinuity of sampling typical for conventional methods. The concentrations of nitrophenolic compounds were calculated from the absorbance values determined automatically by BIOSCREEN C. Verification of the method was based on the comparison of results with the conventional HPLC method results. The values of the rate and saturation constants were comparable for both the microtiter plate-based assay and the conventional HPLC method. The automatic method described here seems to be efficient for the screening degradation studies, which requires the treatment of quantity of samples.

• MeSH
• Arthrobacter růst a vývoj   izolace a purifikace   metabolismus   MeSH
• bakteriologické techniky přístrojové vybavení   metody   MeSH
• biodegradace MeSH
• katecholy metabolismus   MeSH
• kinetika MeSH
• kultivační média MeSH
• molekulární sekvence - údaje MeSH
• nitrofenoly metabolismus   MeSH
• půdní mikrobiologie * MeSH
• Rhodococcus klasifikace   genetika   izolace a purifikace   metabolismus   MeSH
• sekvenční analýza DNA MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 4-nitrocatechol MeSH Prohlížeč
• katecholy MeSH
• kultivační média MeSH
• nitrofenoly MeSH

The X-ray structure of cold-active beta-galactosidase (isoenzyme C-2-2-1) from an Antarctic bacterium Arthrobacter sp. C2-2 was solved at 1.9A resolution. The enzyme forms 660 kDa hexamers with active sites opened to the central cavity of the hexamer and connected by eight channels with exterior solvent. To our best knowledge, this is the first cold-active beta-galactosidase with known structure and also the first known beta-galactosidase structure in the form of compact hexamers. The hexamer organization regulates access of substrates and ligands to six active sites and this unique packing, present also in solution, raises questions about its purpose and function. This enzyme belongs to glycosyl hydrolase family 2, similarly to Escherichia coli beta-galactosidase, forming tetramers necessary for its enzymatic function. However, we discovered significant differences between these two enzymes affecting the ability of tetramer/hexamer formation and complementation of the active site. This structure reveals new insights into the cold-adaptation mechanisms of enzymatic pathways of extremophiles.

• MeSH
• Arthrobacter enzymologie   MeSH
• bakteriální proteiny chemie   genetika   metabolismus   MeSH
• beta-galaktosidasa chemie   genetika   metabolismus   MeSH
• ionty chemie   MeSH
• krystalografie rentgenová MeSH
• kvarterní struktura proteinů * MeSH
• lidé MeSH
• molekulární modely MeSH
• molekulární sekvence - údaje MeSH
• nízká teplota * MeSH
• rozpouštědla chemie   MeSH
• sekvence aminokyselin MeSH
• sekvenční seřazení MeSH
• vazebná místa MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bakteriální proteiny MeSH
• beta-galaktosidasa MeSH
• ionty MeSH
• rozpouštědla MeSH