The expression of Ruminococcus flavefaciens 007S cellulases in different incubation time points (growth stages) and their substrate inducibility were analyzed by comparing the zymogram expression ...profiles of cultures grown on insoluble cellulose (Avicel) with cellobiose-grown cultures. The molecular weights of the enzymes were compared to (putative) cellulases encoded in the R. flavefaciens FD-1 genome.
Microbial biosensors are analytical devices capable of sensing substances in the environment due to the specific biological reaction of the microorganism or its parts. Construction of a microbial ...biosensor requires knowledge of microbial response to the specific analyte. Linking this response with the quantitative data, using a transducer, is the crucial step in the construction of a biosensor. Regarding the transducer type, biosensors are divided into electrochemical, optical biosensors and microbial fuel cells. The use of the proper configuration depends on the selection of the biosensing element. With the use of transgenic E. coli strains, bioluminescence or fluorescence based biosensors were developed. Microbial fuel cells enable the use of the heterogeneous microbial populations, isolated from wastewater. Different microorganisms are used for different pollutants – pesticides, heavy metals, phenolic compounds, organic waste, etc. Biosensing enables measurement of their concentration and their toxic or genotoxic effects on the microbes. Increasing environmental awareness has contributed to the increase of interest for biomonitoring. Although technologies, such as bioinformatics and genetic engineering, allow us to design complex and efficient microbial biosensors for environmental pollutants, the transfer of the laboratory work to the field still remains a problem to solve.
1 Institute of Animal Physiology and Genetics, Czech Academy of Sciences, P átelství 560, 104 00, Prague 10, Uh ín ves, Czech Republic
2 University of Ljubljana, Biotechnical Faculty, Zootechnical ...Dept, Dom ale, Slovenia
3 Hokkaido University, Graduate School of Agriculture, Sapporo 060-8589, Japan
Correspondence Jan Kope n kopecny{at}iapg.cas.cz
Two novel Gram-negative, anaerobic, non-spore-forming, butyrate-producing bacterial species, strains Mz 5 T and JK 615 T , were isolated from the rumen fluid of cow and sheep. Both strains were curved rods that were motile by means of single polar or subpolar flagellum and common in the rumen microbial ecosystem. Strain Mz 5 T produced high xylanase, proteinase, pectin hydrolase and DNase activities; 1,4- -endoglucanase was also detected in the culture medium. The bacterium utilized a wide range of carbohydrates. Glucose was fermented to formate, butyrate, lactate, succinate and ethanol. The DNA G+C content was 42·1 mol%. The complete 16S rDNA sequence was obtained and phylogenetic relationships were determined. Strain Mz 5 T and related isolates were located in clostridial cluster XIVa and were closely related to Pseudobutyrivibrio ruminis , Butyrivibrio crossotus , Roseburia cecicola and Eubacterium rectale . The name proposed for this novel bacterium is Pseudobutyrivibrio xylanivorans ; the type strain is Mz 5 T (=DSM 14809 T =ATCC BAA-455 T ). Strain JK 615 T produced no fibrolytic activity, but utilized a wide range of carbohydrates. Glucose was fermented to formate, acetate, butyrate and ethanol. The DNA G+C content was 44·8 mol%. The complete 16S rDNA sequence was obtained and phylogenetic relationships were determined. Strain JK 615 T was located in clostridial cluster XIVa and was closely related to Clostridium proteoclasticum , Butyrivibrio fibrisolvens and Eubacterium halii . The name proposed for this novel bacterium is Butyrivibrio hungatei ; the type strain is JK 615 T (=DSM 14810 T =ATCC BAA-456 T ).
Published online ahead of print on 9 August 2002 as DOI 10.1099/ijs.0.02345-0.
The EMBL accession numbers for the 16S rDNA sequences of Pseudobutyrivibrio xylanivorans Mz 5 T , Pseudobutyrivibrio ruminis JK 626, Pseudobutyrivibrio xylanivorans JK 23/2, Pseudobutyrivibrio xylanivorans JK 633, Clostridium proteoclasticum UC 142 and Butyrivibrio hungatei JK 615 T are AJ428548AJ428553, respectively.
Successful biogas production is based on stable or adaptable microbial community structure and activity which depends on type of substrate used and several physico-chemical conditions in the ...bioreactor. Monitoring those and the dynamics of microbiota is important for planning and optimizing the biogas process, avoiding critical points and reaching the maximum methane yield. Methanogens are extremely difficult to study with culture-based methods. Molecular methods for microbial community structure analysis in biogas reactors, which offer qualitative and quantitative information on bacterial and archaeal species and their microbial community changes, and causes for process instability are surveyed in this review. For comparative studies semi-quantitative, rapid and cheap techniques like T-RFLP, DGGE and TGGE are used. More laborious and expensive techniques with high-throughput like semi-quantitative FISH and DNA microarrays and also quantitative techniques like qPCR and sequencing are used for phylogenetic analysis. Technique type adequacy for certain study depends on what information is needed and on several advantages and disadvantages every technique possesses.
Estrogenic activity has been detected in aquatic ecosystems across the world. However, there is a lack of such data for Slovenian wastewaters and surface waters. The Slovenian monitoring program of ...effluents discharged into surface waters does not require that emissions of natural and synthetic estrogens into aquatic environments be assessed and controlled. In our study, we assessed the potential estrogenicity of wastewater samples from three wastewater treatment plants using a yeast estrogen screen assay (YES assay). Due to the high inhibition of yeast growth in samples obtained during our first sampling period, it was impossible to detect any estrogenic activity. An additional silica gel clean-up step reduced the toxicity of samples collected during our second sampling period; as a result, we were able to record up to 95% relative estrogenic activity inhibition. Deconjugation of the estrogens did not significantly influence our results. We detected estrogenic activity using a YES assay in almost all influent and effluent samples tested, which suggests that the wastewater treatment plants (WWTPs) examined do not effectively remove (xeno)estrogens from wastewaters. Our results suggest that a YES assay is an appropriate screening method for monitoring estrogenic activity in effluents. However, prediction of the potential impacts of wastewater (xeno)estrogens on aquatic organisms require additional in vitro and in vivo assays.
A bacterial model system (Pseudomonas putida DSM 50026) was used in this research to assess potential effect of five selected chemically diverse environmental pollutants on cell membranes. Long chain ...fatty acid profiles of cultures exposed to environmentally relevant concentrations of atrazine (ATR), metolachlor (MET), pentachlorobiphenyl (PCB), hexachlorobenzene (HCB) and fluoranthene (FL), were analyzed and compared to non-exposed cultures. To assess sensitivity of membrane-based responses, the impact of each toxicant on culture growth was also followed spectrophotometrically. Results revealed changes in fatty acid profiles when cells were exposed to PCB, HCB and FL in concentrations below the inhibitory levels. Moreover, the observed membrane responses were similar to the ones previously associated with adaptation to some membrane-active compounds. On the other hand, exposure of cells to any of the two herbicides, ATR or MET, did not induce any significant changes in fatty acid profiles. However, when combined with a commonly used fertilizer compound, NH4NO3 growth impairment was observed. Synergistic effect of the two herbicides with NH4NO3 might be a consequence of changes in fatty acid profile increasing membrane fluidity, likely induced by NH4+ ions.
Agriculture is a source of emissions of the greenhouse gas methane into the environment. These emissions can be reduced by appropriate storage of animal slurry and manure, with proper fertilization ...and processing of organic agricultural waste into biogas, where methane is captured and used as an energy source. Biogas is a renewable source of energy that is produced by microbial anaerobic digestion in biogas plants. As a substrate in biogas plants using different types of organic biomass such as animal manure and slurry, crop residues, spoilt silage, waste from food processing industry and biodegradable industrial and municipal waste. Biogas can be used to produce heat and electricity or purified to biomethane as a fuel for vehicles. Digestate can be used as a high-quality fertilizer. Biogas as a renewable energy source represents a replacement for fossil fuels, thus reducing greenhouse gas emissions from fossil sources. The system of financial supports for electricity produced from biogas is applied in Slovenia. There were 24 operating biogas plants in Slovenia in year 2014. Slovenian biogas plants currently produce the majority of biogas from energy crops. As only the minority of biogas is produced from animal excrements we will primarily support the development of agricultural microbiogas plants that will use animal excrements and organic waste biomass from agri-food sector as substrates.
Please see the updated PDF with all figures included. (2013) Correction: Expression of Cellulosome Components and Type IV Pili within the Extracellular Proteome of Ruminococcus flavefaciens 007.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Degradation of brewery spent grain as a novel test substrate was explored in routine biochemical methane potential assays (BMP) using three different inocula. Significant differences in the initial ...biogas production rates from spent grain, methane yield coefficients and final spent grain degradation were observed between inocula. Initial and developed communities degrading novel substrate showed significant differences in archaeal community fingerprints. Differences were observed irrespective of substrate identity (no substrate, glucose, spent grain) providing evidence of a significant general influence of BMP incubation on the microbial phylotypes. A linear relationship between microbial community flexibility in BMP assay and corresponding initial biogas production rates was identified as a novel parameter to diagnose anaerobic processes, particularly under dynamic conditions like start-up.
Physicochemical analyses of polluted soils are limited in their ability to determine all hazardous compounds, their bioavailability, and their combined effects on living organisms. Bioassays, on the ...other hand, can evaluate environmental quality more accurately. This study assesses the genotoxic potential of water extracts from soil polluted with metals (Pb, Cd, and Zn) by the former lead smelter in Žerjav, Slovenia using comet assay with Tetrahymena thermophila and human hepatoma cells (HepG2). In addition, the toxicity of soil samples and their extracts was evaluated using Vibrio fischeri and delayed fluorescence of Lemna minor. Chemical analyses of metals using atomic absorption spectrophotometry (AAS) was performed for comparison. Measurements of the total metal concentrations showed that four of five plots near the former lead smelter were highly contaminated with Pb, Cd, and Zn, but the amount of metals in water/soil extracts was low at all the sampling plots. Genotoxicity was demonstrated using T. thermophila for the majority of the extracts, and HepG2 cells for only some of the extracts. Whereas V. fischeri indicated a gradual decrease in soil toxicity with greater distance from the smelter, the toxicity of extracts did not correlate with proximity. Low concentrations of metals in water extracts stimulated L. minor growth. The results indicate that comet assay with T. thermophila and HepG2 cells and the BSPT with V. fischeri are suitable protocols for screening the genotoxic and toxic potential of water/soil extracts by comet assay, whereas chemical analyses of total metal concentrations in soil do not solely suffice for evaluating metal pollution in the environment. Biological assays are thus crucial for risk assessment.
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