scholarly journals Inhibition of Nitrifiers and Methanotrophs from an Agricultural Humisol by Allylsulfide and Its Implications for Environmental Studies

1999 ◽  
Vol 65 (6) ◽  
pp. 2461-2465 ◽  
Author(s):  
Josh D. Neufeld ◽  
Roger Knowles
Keyword(s):  
Methane Oxidation ◽  
Enrichment Culture ◽  
Environmental Studies ◽  
Ammonia Monooxygenase ◽  
Enrichment Cultures ◽  
Pure Cultures

ABSTRACT Allylsulfide, an inhibitor of ammonia monooxygenase, was tested to determine its ability to inhibit nitrification and methane oxidation in pure cultures, in agricultural humisol enrichment cultures, and in humisol slurries. We confirmed that allylsulfide is a differential inhibitor of cultures of nitrifiers and methanotrophs at concentrations of 1 and 200 μM, respectively, which result in 50% inhibition. However, although a nitrifying enrichment culture added to sterilized humisol was inhibited 50% by 4 μM allylsulfide, 500 μM allylsulfide was necessary for 50% inhibition of the endogenous nitrifying activity in nonsterile humisol. We concluded that native nitrifiers were protected, possibly by being in colonial aggregates or sheltered microenvironments.

A modification of the method using cellulose overlay agar to isolate and purify cellulolytic cytophagas from enrichment culture

1992 ◽  
Vol 38 (7) ◽  
pp. 687-689 ◽  
Author(s):  
R. A. Drijber ◽  
W. B. McGill
Keyword(s):  
Key Words ◽  
Enrichment Culture ◽  
Soil Samples ◽  
Existing Problems ◽  
Enrichment Cultures ◽  
Pure Cultures ◽  
Back Door ◽  
Agar Surface ◽  
Agar Method

We report here on a modification of the cellulose overlay agar method for isolating and purifying cellulolytic cytophagas from enrichment cultures. We call it the "back-door" method, and it overcomes two existing problems. First, it prevents recontamination with organisms growing on the agar surface. Second, it permits purification of cellulolytic cytophagas that are unable to utilize glucose or that are accompanied by a rapidly growing contaminant with spreading habit. Pure cultures of cellulolytic cytophagas were obtained from five enrichment cultures of nine soil samples examined. Two limitations are that (i) the cytophaga must be able to penetrate the overlay and (ii) some noncellulolytic cytophagas may also penetrate the overlay to yield cocultures. In conclusion, the back-door method can be used both to isolate and purify cellulolytic cytophagas from soils, using only a cellulose-based medium. Key words: back-door method, cellulolytic cytophagas, cellulose overlay agar, cellulolysis.

scholarly journals Identifying Hidden Viable Bacterial Taxa in Tropical Forest Soils Using Amplicon Sequencing of Enrichment Cultures

Biology ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 569
Author(s):  
Chakriya Sansupa ◽  
Sara Fareed Mohamed Wahdan ◽  
Terd Disayathanoowat ◽  
Witoon Purahong
Keyword(s):  
Bacterial Community ◽  
Forest Soil ◽  
Culture Media ◽  
Enrichment Culture ◽  
Sequence Similarity ◽  
Illumina Miseq ◽  
Amplicon Sequencing ◽  
Soil Samples ◽  
Enrichment Cultures ◽  
Total Community

This study aims to estimate the proportion and diversity of soil bacteria derived from eDNA-based and culture-based methods. Specifically, we used Illumina Miseq to sequence and characterize the bacterial communities from (i) DNA extracted directly from forest soil and (ii) DNA extracted from a mixture of bacterial colonies obtained by enrichment cultures on agar plates of the same forest soil samples. The amplicon sequencing of enrichment cultures allowed us to rapidly screen a culturable community in an environmental sample. In comparison with an eDNA community (based on a 97% sequence similarity threshold), the fact that enrichment cultures could capture both rare and abundant bacterial taxa in forest soil samples was demonstrated. Enrichment culture and eDNA communities shared 2% of OTUs detected in total community, whereas 88% of enrichment cultures community (15% of total community) could not be detected by eDNA. The enrichment culture-based methods observed 17% of the bacteria in total community. FAPROTAX functional prediction showed that the rare and unique taxa, which were detected with the enrichment cultures, have potential to perform important functions in soil systems. We suggest that enrichment culture-based amplicon sequencing could be a beneficial approach to evaluate a cultured bacterial community. Combining this approach together with the eDNA method could provide more comprehensive information of a bacterial community. We expected that more unique cultured taxa could be detected if further studies used both selective and non-selective culture media to enrich bacteria at the first step.

An Improved Screening Method for the Detection and Isolation of Escherichia coli 0157:H7 From Meat, Incorporating the 3M Petrifilm™ Test Kit - HEC - for Hemorrhagic Escherichia coli 0157:H7

1990 ◽  
Vol 53 (11) ◽  
pp. 936-940 ◽  
Author(s):  
ANITA J. G. OKREND ◽  
BONNIE E. ROSE ◽  
RICHARD MATNER
Keyword(s):  
Escherichia Coli ◽  
Screening Program ◽  
Enrichment Culture ◽  
Screening Method ◽  
Meat Sample ◽  
E Coli ◽  
Enrichment Cultures ◽  
Poultry Products ◽  
Test Kit ◽  
Cooked Meat

A screening method was devised incorporating a commercially available reactive disc blot ELISA for Escherichia coli 0157 antigen, into a cultural screening program for the isolation of E. coli 0157:H7 from meat and poultry products. The method includes the inoculation of a raw or cooked meat sample into an enrichment broth, incubation with shaking at 37°C for 6 to 8 h, followed by inoculation of 3M Petrifilm™ E. coli Count plates with dilutions of the enrichment culture. The Petrifilm plates were incubated at 42°C for 18 h and tested for the presence of the 0157 antigen. The enrichment cultures were reincubated static at 35°C after the initial shaken incubation. Isolation was attempted from the positive Petrifilm plates by both a direct picking and streaking method and by the 3M Prompt™ isolation method. Isolation also was attempted from the 24-h enrichment cultures by spread plating serial dilutions on 150 × 15 mm MacConkey sorbitol agar (MSA) and MSA with 5-bromo-4-chloro-3-indoxyl-β-D-glucuronic acid cyclohexylammonium salt (BCIG). This fast and efficient screening procedure identifies negative and presumptive positive samples in 26–28 h. Isolation and confirmation of the presumptive positive isolates require an additional 3 to 4 d.

Metabolism of carbaryl and carbofuran by soil-enrichment and bacterial cultures

1984 ◽  
Vol 30 (12) ◽  
pp. 1458-1466 ◽  
Author(s):  
B. S. Rajagopal ◽  
V. R. Rao ◽  
G. Nagendrappa ◽  
N. Sethunathan
Keyword(s):  
Enrichment Culture ◽  
Side Chain ◽  
Bacillus Sp ◽  
Mineral Salts ◽  
Prolonged Incubation ◽  
Soil Enrichment ◽  
Enrichment Cultures ◽  
Hydrolysis Products ◽  
Carbamate Insecticides ◽  
Major Route

Metabolism of side chain and ring 14C-labelled carbaryl and carbofuran in a mineral salts medium by soil-enrichment cultures and a Bacillus sp. was studied. A change in the substrate of the medium from carbaryl to carbofuran led to a marked shift in the dominant bacterium from Bacillus sp. to Arthrobacter sp. although carbaryl-enrichment culture was the primary inoculum in both media. Hydrolysis was the major route of microbial degradation of both carbamate insecticides. During carbaryl degradation by enrichment cultures and Bacillus sp., 1-naphthol and 1,4-naphthoquinone accumulated in the medium. Of the three metabolites formed from carbofuran, 3-hydroxycarbofuran and 3-ketocarbofuran were further metabolized rapidly, while carbofuran phenol was resistant to further degradation. Evolution of 14CO2 and other gaseous 14C-labelled products from both side chain and ring labels was negligible. This and slow degradation of the hydrolysis products led to significant accumulation of 14C in the medium even after prolonged incubation.

scholarly journals Anaerobic oxidation of methane in grassland soils used for cattle husbandry

2012 ◽  
Vol 9 (10) ◽  
pp. 3891-3899 ◽  
Author(s):  
A. Bannert ◽  
C. Bogen ◽  
J. Esperschütz ◽  
A. Koubová ◽  
F. Buegger ◽  
...  
Keyword(s):  
Methane Oxidation ◽  
Enrichment Culture ◽  
Anaerobic Oxidation Of Methane ◽  
Anaerobic Oxidation ◽  
Incubation Experiment ◽  
Nutrient Source ◽  
Oxidation Activity ◽  
Oxidation Of Methane ◽  
Cattle Husbandry

Abstract. While the importance of anaerobic methane oxidation has been reported for marine ecosystems, the role of this process in soils is still questionable. Grasslands used as pastures for cattle overwintering show an increase in anaerobic soil micro-sites caused by animal treading and excrement deposition. Therefore, anaerobic potential methane oxidation activity of severely impacted soil from a cattle winter pasture was investigated in an incubation experiment under anaerobic conditions using 13C-labelled methane. We were able to detect a high microbial activity utilizing CH4 as nutrient source shown by the respiration of 13CO2. Measurements of possible terminal electron acceptors for anaerobic oxidation of methane were carried out. Soil sulfate concentrations were too low to explain the oxidation of the amount of methane added, but enough nitrate and iron(III) were detected. However, only nitrate was consumed during the experiment. 13C-PLFA analyses clearly showed the utilization of CH4 as nutrient source mainly by organisms harbouring 16:1ω7 PLFAs. These lipids were also found as most 13C-enriched fatty acids by Raghoebarsing et al. (2006) after addition of 13CH4 to an enrichment culture coupling denitrification of nitrate to anaerobic oxidation of methane. This might be an indication for anaerobic oxidation of methane by relatives of "Candidatus Methylomirabilis oxyfera" in the investigated grassland soil under the conditions of the incubation experiment.

Copper Recovery by Bioleaching of Chalcopyrite: A Microcalorimetric Approach for the Fast Determination of Bioleaching Activity

2013 ◽  
Vol 825 ◽  
pp. 322-325
Author(s):  
Beate Krok ◽  
Axel Schippers ◽  
Wolfgang Sand
Keyword(s):  
Enrichment Culture ◽  
Sulfide Oxidation ◽  
Exothermic Reaction ◽  
Metal Sulfide ◽  
Copper Recovery ◽  
Heat Output ◽  
Low Grade ◽  
Non Invasive ◽  
Pure Cultures ◽  
Invasive Method

Low grade copper ores containing chalcopyrite are increasingly used for copper recovery via biomining. Since metal sulfide oxidation is an exothememic process, bioleaching activity can be measured due to the heat output by microcalorimetry, which is a non-destructive and non-invasive method. The bioleaching activity of pure cultures ofSulfolobus metallicus,Metallosphaera hakonensisand a moderate thermophilic enrichment culture on high grade chalcopyrite was evaluated. Chalcopyrite leaching by microorganisms showed a higher copper recovery than sterile controls. Chemical chalcopyrite leaching by acid produced heat due to the exothermic reaction, the heat output was increased while metal sulfide oxidation by microorganisms.

scholarly journals Bacterial Oxidation of Dibromomethane and Methyl Bromide in Natural Waters and Enrichment Cultures

1998 ◽  
Vol 64 (12) ◽  
pp. 4629-4636 ◽  
Author(s):  
K. D. Goodwin ◽  
J. K. Schaefer ◽  
R. S. Oremland
Keyword(s):  
Carbon Source ◽  
Methane Oxidation ◽  
Methyl Bromide ◽  
Half Life ◽  
Sole Carbon Source ◽  
Natural Waters ◽  
The Other ◽  
Bacterial Oxidation ◽  
Enrichment Cultures ◽  
Saline Waters

ABSTRACT Bacterial oxidation of14CH2Br2 and14CH3Br was measured in freshwater, estuarine, seawater, and hypersaline-alkaline samples. In general, bacteria from the various sites oxidized similar amounts of14CH2Br2 and comparatively less 14CH3Br. Bacterial oxidation of14CH3Br was rapid in freshwater samples compared to bacterial oxidation of 14CH3Br in more saline waters. Freshwater was also the only site in which methyl fluoride-sensitive bacteria (e.g., methanotrophs or nitrifiers) governed brominated methane oxidation. Half-life calculations indicated that bacterial oxidation of CH2Br2 was potentially significant in all of the waters tested. In contrast, only in freshwater was bacterial oxidation of CH3Br as fast as chemical removal. The values calculated for more saline sites suggested that bacterial oxidation of CH3Br was relatively slow compared to chemical and physical loss mechanisms. However, enrichment cultures demonstrated that bacteria in seawater can rapidly oxidize brominated methanes. Two distinct cultures of nonmethanotrophic methylotrophs were recovered; one of these cultures was able to utilize CH2Br2 as a sole carbon source, and the other was able to utilize CH3Br as a sole carbon source.

scholarly journals Biodegradation of Endocrine Disruptors in Solid-Liquid Two-Phase Partitioning Systems by Enrichment Cultures

2013 ◽  
Vol 79 (15) ◽  
pp. 4701-4711 ◽  
Author(s):  
Richard Villemur ◽  
Silvia Cristina Cunha dos Santos ◽  
Julianne Ouellette ◽  
Pierre Juteau ◽  
François Lépine ◽  
...  
Keyword(s):  
Endocrine Disruptors ◽  
Urban Areas ◽  
Enrichment Culture ◽  
16S Rrna Gene Sequencing ◽  
Rrna Gene ◽  
Two Phase ◽  
Content Type ◽  
Phase Partitioning ◽  
Enrichment Cultures ◽  
Solid Liquid

ABSTRACTNaturally occurring and synthetic estrogens and other molecules from industrial sources strongly contribute to the endocrine disruption of urban wastewater. Because of the presence of these molecules in low but effective concentrations in wastewaters, these endocrine disruptors (EDs) are only partially removed after most wastewater treatments, reflecting the presence of these molecules in rivers in urban areas. The development of a two-phase partitioning bioreactor (TPPB) might be an effective strategy for the removal of EDs from wastewater plant effluents. Here, we describe the establishment of three ED-degrading microbial enrichment cultures adapted to a solid-liquid two-phase partitioning system using Hytrel as the immiscible water phase and loaded with estrone, estradiol, estriol, ethynylestradiol, nonylphenol, and bisphenol A. All molecules except ethynylestradiol were degraded in the enrichment cultures. The bacterial composition of the three enrichment cultures was determined using 16S rRNA gene sequencing and showed sequences affiliated with bacteria associated with the degradation of these compounds, such asSphingomonadales. OneRhodococcusisolate capable of degrading estrone, estradiol, and estriol was isolated from one enrichment culture. These results highlight the great potential for the development of TPPB for the degradation of highly diluted EDs in water effluents.

Environmentally friendly bacteria?

1994 ◽  
Vol 13 (8) ◽  
pp. 574-575
Author(s):  
Alan J Paine
Keyword(s):  
Organic Compounds ◽  
Enrichment Culture ◽  
Anaerobic Bacteria ◽  
Genetically Engineered ◽  
Reductive Dehalogenation ◽  
P450 Monooxygenase ◽  
Single Strain ◽  
Selective Enrichment ◽  
Genes Encoding ◽  
Pure Cultures

The decomposition of organic compounds by bacteria has been studied for almost a century, during which time selective enrichment culture has generated microorganisms capable of metabolizing thousands of organic compounds. But attempts to obtain pure cultures of bacteria that can metabolize highly halogenated compounds, a large and important class of pollutants, have been largely unsuccessful. Polyhalogenated compounds are most frequently metabolized by anaerobic bacteria as a result of reductive dehalogenation reactions, the products of which are typically substrates for bacterial oxygenases. Complete metabolism of polyhalogenated compounds therefore necessitates the sequential use of anaerobic and aerobic bacteria. Here we combine seven genes encoding two multi-component oxygenases in a single strain of Pseudomonas which as a result metabolizes polyhalogenated compounds by means of sequential reductive and oxidative reactions to yield non-toxic products. Cytochrome P450 monooxygenase reduces polyhalogenated compounds, which are bound at the camphor-binding site, under subatmospheric oxygen tensions. We find that these reduction products are oxidizable substrates for toluene dioxygenase. Perhalogenated chlorofluorcarbons also act as substrates for the genetically engineered strain.

Isolation and Characterization of Phenol-Degrading Denitrifying Bacteria

1998 ◽  
Vol 64 (7) ◽  
pp. 2432-2438 ◽  
Author(s):  
Paula M. van Schie ◽  
L. Y. Young
Keyword(s):  
New York ◽  
Enrichment Culture ◽  
Phenol Degradation ◽  
Sole Source ◽  
New Members ◽  
Isolation And Characterization ◽  
East River ◽  
Pure Cultures ◽  
Orange Grove ◽  
Metabolic Properties

ABSTRACT Phenol is a man-made as well as a naturally occurring aromatic compound and an important intermediate in the biodegradation of natural and industrial aromatic compounds. Whereas many microorganisms that are capable of aerobic phenol degradation have been isolated, only a few phenol-degrading anaerobic organisms have been described to date. In this study, three novel nitrate-reducing microorganisms that are capable of using phenol as a sole source of carbon were isolated and characterized. Phenol-degrading denitrifying pure cultures were obtained by enrichment culture from anaerobic sediments obtained from three different geographic locations, the East River in New York, N.Y., a Florida orange grove, and a rain forest in Costa Rica. The three strains were shown to be different from each other based on physiologic and metabolic properties. Even though analysis of membrane fatty acids did not result in identification of the organisms, the fatty acid profiles were found to be similar to those of Azoarcusspecies. Sequence analysis of 16S ribosomal DNA also indicated that the phenol-degrading isolates were closely related to members of the genusAzoarcus. The results of this study add three new members to the genus Azoarcus, which previously comprised only nitrogen-fixing species associated with plant roots and denitrifying toluene degraders.

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