Metabolites of polychlorinated biphenyls (PCBs)-hydroxylated PCBs (OH-PCBs), chlorobenzyl alcohols (CB-OHs), and chlorobenzaldehydes (CB-CHOs)-were incubated in vitro with the extracellular liquid of Pleurotus ostreatus, which contains mainly laccase and low manganese-dependent peroxidase (MnP) activity. The enzymes were able to decrease the amount of most of the tested OH-PCBs by > 80% within 1 h; the removal of more recalcitrant OH-PCBs was greatly enhanced by the addition of the laccase mediator syringaldehyde. Conversely, glutathione substantially hindered the reaction, suggesting that it acted as a laccase inhibitor. Hydroxylated dibenzofuran and chlorobenzoic acid were identified as transformation products of OH-PCBs. The extracellular enzymes also oxidized the CB-OHs to the corresponding CB-CHOs on the order of hours to days; however, the mediated and nonmediated setups exhibited only slight differences, and the participating enzymes could not be determined. When CB-CHOs were used as the substrates, only partial transformation was observed. In an additional experiment, the extracellular liquid of Irpex lacteus, which contains predominantly MnP, was able to efficiently transform CB-CHOs with the aid of glutathione; mono- and di-chloroacetophenones were detected as transformation products. These results demonstrate that extracellular enzymes of ligninolytic fungi can act on a wide range of PCB metabolites, emphasizing their potential for bioremediation.

• Klíčová slova
• Irpex lacteus, Pleurotus ostreatus, biodegradation, chlorobenzaldehydes, chlorobenzyl alcohols, hydroxylated PCBs,
• Publikační typ
• časopisecké články MeSH

The complete genome sequence of Rhodococcus sp. WAY2 (WAY2) consists of a circular chromosome, three linear replicons and a small circular plasmid. The linear replicons contain typical actinobacterial invertron-type telomeres with the central CGTXCGC motif. Comparative phylogenetic analysis of the 16S rRNA gene along with phylogenomic analysis based on the genome-to-genome blast distance phylogeny (GBDP) algorithm and digital DNA-DNA hybridization (dDDH) with other Rhodococcus type strains resulted in a clear differentiation of WAY2, which is likely a new species. The genome of WAY2 contains five distinct clusters of bph, etb and nah genes, putatively involved in the degradation of several aromatic compounds. These clusters are distributed throughout the linear plasmids. The high sequence homology of the ring-hydroxylating subunits of these systems with other known enzymes has allowed us to model the range of aromatic substrates they could degrade. Further functional characterization revealed that WAY2 was able to grow with biphenyl, naphthalene and xylene as sole carbon and energy sources, and could oxidize multiple aromatic compounds, including ethylbenzene, phenanthrene, dibenzofuran and toluene. In addition, WAY2 was able to co-metabolize 23 polychlorinated biphenyl congeners, consistent with the five different ring-hydroxylating systems encoded by its genome. WAY2 could also use n-alkanes of various chain-lengths as a sole carbon source, probably due to the presence of alkB and ladA gene copies, which are only found in its chromosome. These results show that WAY2 has a potential to be used for the biodegradation of multiple organic compounds.

• Klíčová slova
• PAH, PCB, Rhodococcus, biodegradation, complete genome, hydrocarbons,
• MeSH
• alkylační opravný homolog genetika   metabolismus   MeSH
• biodegradace MeSH
• fylogeneze MeSH
• naftaleny metabolismus   MeSH
• polychlorované bifenyly chemie   MeSH
• Rhodococcus klasifikace   genetika   růst a vývoj   MeSH
• RNA ribozomální 16S genetika   MeSH
• sekvenování celého genomu metody   MeSH
• shluková analýza MeSH
• vysoce účinné nukleotidové sekvenování MeSH
• xyleny metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• alkylační opravný homolog MeSH
• naftaleny MeSH
• naphthalene MeSH Prohlížeč
• polychlorované bifenyly MeSH
• RNA ribozomální 16S MeSH
• xyleny MeSH

Chlorhexidine (CHX) and octenidine (OCT), antimicrobial compounds used in oral care products (toothpastes and mouthwashes), were recently revealed to interfere with human sex hormone receptor pathways. Experiments employing model organisms-white-rot fungi Irpex lacteus and Pleurotus ostreatus-were carried out in order to investigate the biodegradability of these endocrine-disrupting compounds and the capability of the fungi and their extracellular enzyme apparatuses to biodegrade CHX and OCT. Up to 70% ± 6% of CHX was eliminated in comparison with a heat-killed control after 21 days of in vivo incubation. An additional in vitro experiment confirmed manganese-dependent peroxidase and laccase are partially responsible for the removal of CHX. Up to 48% ± 7% of OCT was removed in the same in vivo experiment, but the strong sorption of OCT on fungal biomass prevented a clear evaluation of the involvement of the fungi or extracellular enzymes. On the other hand, metabolites indicating the enzymatic transformation of both CHX and OCT were detected and their chemical structures were proposed by means of liquid chromatography-mass spectrometry. Complete biodegradation by the ligninolytic fungi was not achieved for any of the studied analytes, which emphasizes their recalcitrant character with low possibility to be removed from the environment.

• Klíčová slova
• chlorhexidine, dental hygiene, laccase, ligninolytic fungi, manganese-dependent peroxidase, octenidine, personal care products, quaternary ammonium compounds, recalcitrant pollutant,
• MeSH
• antiinfekční látky lokální metabolismus   MeSH
• biodegradace * MeSH
• chlorhexidin chemie   metabolismus   MeSH
• houby metabolismus   MeSH
• iminy MeSH
• lidé MeSH
• metabolomika metody   MeSH
• pyridiny chemie   metabolismus   MeSH
• stomatologická péče MeSH
• transformace genetická MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antiinfekční látky lokální MeSH
• chlorhexidin MeSH
• iminy MeSH
• octenidine MeSH Prohlížeč
• pyridiny MeSH

Extended soil contamination by polychlorinated biphenyls (PCBs) represents a global environmental issue that can hardly be addressed with the conventional remediation treatments. Rhizoremediation is a sustainable alternative, exploiting plants to stimulate in situ the degradative bacterial communities naturally occurring in historically polluted areas. This approach can be enhanced by the use of bacterial strains that combine PCB degradation potential with the ability to promote plant and root development. With this aim, we established a collection of aerobic bacteria isolated from the soil of the highly PCB-polluted site "SIN Brescia-Caffaro" (Italy) biostimulated by the plant Phalaris arundinacea. The strains, selected on biphenyl and plant secondary metabolites provided as unique carbon source, were largely dominated by Actinobacteria and a significant number showed traits of interest for remediation, harbouring genes homologous to bphA, involved in the PCB oxidation pathway, and displaying 2,3-catechol dioxygenase activity and emulsification properties. Several strains also showed the potential to alleviate plant stress through 1-aminocyclopropane-1-carboxylate deaminase activity. In particular, we identified three Rhodococcus strains able to degrade in vitro several PCB congeners and to promote lateral root emergence in the model plant Arabidopsis thaliana in vivo. In addition, these strains showed the capacity to colonize the root system and to increase the plant biomass in PCB contaminated soil, making them ideal candidates to sustain microbial-assisted PCB rhizoremediation through a bioaugmentation approach.

• MeSH
• Arabidopsis růst a vývoj   mikrobiologie   MeSH
• bakteriální proteiny genetika   metabolismus   MeSH
• biodegradace MeSH
• exprese genu MeSH
• katechol-2,3-dioxygenasa genetika   metabolismus   MeSH
• kořeny rostlin růst a vývoj   mikrobiologie   MeSH
• látky znečišťující půdu metabolismus   MeSH
• lyasy štěpící vazby C-C genetika   metabolismus   MeSH
• oxidace-redukce MeSH
• Phalaris růst a vývoj   mikrobiologie   MeSH
• polychlorované bifenyly metabolismus   MeSH
• půda chemie   MeSH
• půdní mikrobiologie MeSH
• Rhodococcus enzymologie   genetika   MeSH
• sekundární metabolismus genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 1-aminocyclopropane-1-carboxylate deaminase MeSH Prohlížeč
• bakteriální proteiny MeSH
• katechol-2,3-dioxygenasa MeSH
• látky znečišťující půdu MeSH
• lyasy štěpící vazby C-C MeSH
• polychlorované bifenyly MeSH
• půda MeSH

In this study, following its isolation from contaminated soil, the genomic sequence of Pseudomonas alcaliphila strain JAB1 (=DSM 26533), a biphenyl-degrading bacterium, is reported and analyzed in relation to its extensive degradative capabilities. The P. alcaliphila JAB1 genome (GenBank accession no. CP016162) consists of a single 5.34 Mbp-long chromosome with a GC content of 62.5%. Gene function was assigned to 3816 of the 4908 predicted genes. The genome harbors a bph gene cluster, permitting degradation of biphenyl and many congeners of polychlorinated biphenyls (PCBs), a ben gene cluster, enabling benzoate and its derivatives to be degraded, and phe gene cluster, which permits phenol degradation. In addition, P. alcaliphila JAB1 is capable of cometabolically degrading cis-1,2-dichloroethylene (cDCE) when grown on phenol. The strain carries both catechol and protocatechuate branches of the β-ketoadipate pathway, which is used to funnel the pollutants to the central metabolism. Furthermore, we propose that clustering of MALDI-TOF MS spectra with closest phylogenetic relatives should be used when taxonomically classifying the isolated bacterium; this, together with 16S rRNA gene sequence and chemotaxonomic data analyses, enables more precise identification of the culture at the species level.

• Klíčová slova
• Aromatic compounds, Biodegradation, Bioremediation, Biphenyl, Chlorobenzoic acids (CBAs), Dioxygenase, Genome, MALDI-TOF MS, Monooxygenase, Phenol, Polychlorinated biphenyls (PCBs), Pseudomonadaceae, Pseudomonas alcaliphila JAB1, ben genes, bph genes, cis-1,2-dichloroethylene (cDCE), phe genes,
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH

Secondary plant metabolites (SPMEs) play an important role in plant survival in the environment and serve to establish ecological relationships between plants and other organisms. Communication between plants and microorganisms via SPMEs contained in root exudates or derived from litter decomposition is an example of this phenomenon. In this review, the general aspects of rhizodeposition together with the significance of terpenes and phenolic compounds are discussed in detail. We focus specifically on the effect of SPMEs on microbial community structure and metabolic activity in environments contaminated by polychlorinated biphenyls (PCBs) and polyaromatic hydrocarbons (PAHs). Furthermore, a section is devoted to a complex effect of plants and/or their metabolites contained in litter on bioremediation of contaminated sites. New insights are introduced from a study evaluating the effects of SPMEs derived during decomposition of grapefruit peel, lemon peel, and pears on bacterial communities and their ability to degrade PCBs in a long-term contaminated soil. The presented review supports the "secondary compound hypothesis" and demonstrates the potential of SPMEs for increasing the effectiveness of bioremediation processes.

• Klíčová slova
• bioremediation, carbon flow, community structure, secondary plant metabolites (SPMEs),
• MeSH
• Bacteria klasifikace   izolace a purifikace   metabolismus   MeSH
• biodegradace * MeSH
• látky znečišťující půdu chemie   toxicita   MeSH
• polychlorované bifenyly toxicita   MeSH
• půdní mikrobiologie * MeSH
• rostliny metabolismus   mikrobiologie   MeSH
• sekundární metabolismus MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• látky znečišťující půdu MeSH
• polychlorované bifenyly MeSH