The compositions of bacterial groundwater communities of three sites contaminated with chlorinated ethenes were analyzed by pyrosequencing their 16S rRNA genes. For each location, the entire and the active bacterial populations were characterized by independent molecular analysis of the community DNA and RNA. The sites were selected to cover a broad range of different environmental conditions and contamination levels, with tetrachloroethene (PCE) and trichloroethene (TCE) being the primary contaminants. Before sampling the biomass, a long-term monitoring of the polluted locations revealed high concentrations of cis-1,2-dichloroethene (cDCE) and vinyl chloride (VC), which are toxic by-products of the incomplete bacterial degradation of PCE and TCE. The applied pyrosequencing technique enabled known dechlorinators to be identified at a very low detection level (<0.25%) without compromising the detailed analysis of the entire bacterial community of these sites. The study revealed that only a few species dominated the bacterial communities, with Albidiferax ferrireducens being the only highly prominent member found at all three sites. Only a limited number of OTUs with abundances of up to 1% and high sequence identities to known dechlorinating microorganisms were retrieved from the RNA pools of the two highly contaminated sites. The dechlorinating consortium was likely to be comprised of cDCE-assimilating bacteria (Polaromonas spp.), anaerobic organohalide respirers (mainly Geobacter spp.), and Burkholderia spp. involved in cometabolic dechlorination processes, together with methylotrophs (Methylobacter spp.). The deep sequencing results suggest that the indigenous dechlorinating consortia present at the investigated sites can be used as a starting point for future bioremediation activities by stimulating their anaerobic and aerobic chloroethene degradation capacities (i.e. reductive dechlorination, and metabolic and cometabolic oxidation).
- MeSH
- Bacteria účinky léků genetika metabolismus MeSH
- biodegradace MeSH
- chemické látky znečišťující vodu toxicita MeSH
- DNA genetika metabolismus MeSH
- monitorování životního prostředí MeSH
- podzemní voda mikrobiologie MeSH
- polymerázová řetězová reakce MeSH
- RNA ribozomální 16S genetika metabolismus MeSH
- RNA genetika metabolismus MeSH
- společenstvo MeSH
- tetrachlorethylen toxicita MeSH
- trichlorethylen toxicita MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
- Názvy látek
- chemické látky znečišťující vodu MeSH
- DNA MeSH
- RNA ribozomální 16S MeSH
- RNA MeSH
- tetrachlorethylen MeSH
- trichlorethylen MeSH
The toxicity of trichloroethylene was tested in both glass enclosures and in polystyrene immunological plates, and resulted in insignificant correlation of EC₅₀ (evaluated as OD 750 nm). In enclosures, EC₅₀ evaluated as O₂ evolution and as pH increment was highly significant. The optimal time for the assay of TCE in enclosures was 48-72 h; and in plates ca 200 h. After a longer time (e.g. 300 h) TCE diffused from the plates and growth was revived. TCE in low concentrations (ca. 0.1-0.2 g/L) stimulated the growth of some tested organisms, both in plates and in enclosures. Toxicity occurred from ca. 0.35-0.6 g/L (EC₅₀). The testing procedure in enclosures was a suitable method for some volatile substances, giving rapid results.
- MeSH
- chemické látky znečišťující vodu toxicita MeSH
- Chlorophyta účinky léků MeSH
- fotosyntéza účinky léků MeSH
- koncentrace vodíkových iontů MeSH
- sinice účinky léků MeSH
- trichlorethylen toxicita MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- chemické látky znečišťující vodu MeSH
- trichlorethylen MeSH
Experimental studies of simultaneous exposure of the organism to chemical compounds and other unfavourable occupational and social factors are of great importance for the understanding of the mechanisms of combined effect and the detection of the dose-effect dependence. On a total number of 2000 made Wistar rats, 7 series of experiments were carried out in which the combined effect of solvents widely used in industry (acetone, carbon disulphide, trichloroethylene) and noise at varying levels (1-2, 10 Limchr for the solvents and 85, 95 dB A for noise) and duration of exposure (1 1/2-2 and 4 months) was studied. Biological effect was evaluated dynamically using a complex of indices reflecting the state of the principal systems of the organism--the nervous, cardiovascular, endocrine and immune systems. Results of the studies were analysed using a linear model by means of which the types of interaction of the factors could be classified. In all the series of experiments, an antagonistic type of combined effect was found to predominate according to most different indices. The mechanisms underlying the antagonistic interaction between the solvents showing narcotic effect, and noise are discussed.
- MeSH
- aceton toxicita MeSH
- centrální nervový systém účinky léků MeSH
- endokrinní žlázy účinky léků MeSH
- hluk škodlivé účinky MeSH
- inbrední kmeny potkanů MeSH
- krysa rodu Rattus MeSH
- rozpouštědla toxicita MeSH
- sirouhlík toxicita MeSH
- trichlorethylen toxicita MeSH
- tvorba protilátek účinky léků MeSH
- zvířata MeSH
- Check Tag
- krysa rodu Rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- aceton MeSH
- rozpouštědla MeSH
- sirouhlík MeSH
- trichlorethylen MeSH
- Klíčová slova
- TRICHLOROETHYLENE/toxicity *,
- MeSH
- chronická nemoc * MeSH
- nežádoucí účinky léčiv * MeSH
- trichlorethylen toxicita MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- trichlorethylen MeSH
