scholarly journals Synergistic Degradation of Linuron by a Bacterial Consortium and Isolation of a Single Linuron-Degrading Variovorax Strain

2003 ◽  
Vol 69 (3) ◽  
pp. 1532-1541 ◽  
Author(s):  
Winnie Dejonghe ◽  
Ellen Berteloot ◽  
Johan Goris ◽  
Nico Boon ◽  
Katrien Crul ◽  
...  
Keyword(s):  
Denaturing Gradient Gel Electrophoresis ◽  
Enrichment Culture ◽  
Bacterial Community Composition ◽  
Sole Source ◽  
Bacterial Consortium ◽  
The Other ◽  
Rrna Gene ◽  
Comamonas Testosteroni ◽  
Isolation And Identification

ABSTRACT The bacterial community composition of a linuron-degrading enrichment culture and the role of the individual strains in linuron degradation have been determined by a combination of methods, such as denaturing gradient gel electrophoresis of the total 16S rRNA gene pool, isolation and identification of strains, and biodegradation assays. Three strains, Variovorax sp. strain WDL1, Delftia acidovorans WDL34, and Pseudomonas sp. strain WDL5, were isolated directly from the linuron-degrading culture. In addition, subculture of this enrichment culture on potential intermediates in the degradation pathway of linuron (i.e., N,O-dimethylhydroxylamine and 3-chloroaniline) resulted in the isolation of, respectively, Hyphomicrobium sulfonivorans WDL6 and Comamonas testosteroni WDL7. Of these five strains, only Variovorax sp. strain WDL1 was able to use linuron as the sole source of C, N, and energy. WDL1 first converted linuron to 3,4-dichloroaniline (3,4-DCA), which transiently accumulated in the medium but was subsequently degraded. To the best of our knowledge, this is the first report of a strain that degrades linuron further than the aromatic intermediates. Interestingly, the rate of linuron degradation by strain WDL1 was lower than that for the consortium, but was clearly increased when WDL1 was coinoculated with each of the other four strains. D. acidovorans WDL34 and C. testosteroni WDL7 were found to be responsible for degradation of the intermediate 3,4-DCA, and H. sulfonivorans WDL6 was the only strain able to degrade N,O-dimethylhydroxylamine. The role of Pseudomonas sp. strain WDL5 needs to be further elucidated. The degradation of linuron can thus be performed by a single isolate, Variovorax sp. strain WDL1, but is stimulated by a synergistic interaction with the other strains isolated from the same linuron-degrading culture.

scholarly journals Biodegradation of Eugenol byBacillus CereusStrain PN24

2010 ◽  
Vol 7 (s1) ◽  
pp. S474-S480 ◽  
Author(s):  
Jagannath C. Kadakol ◽  
Chandrappa M. Kamanavalli
Keyword(s):  
Vanillic Acid ◽  
Bacterial Strain ◽  
Culture Medium ◽  
Protocatechuic Acid ◽  
Enrichment Culture ◽  
Culture Method ◽  
Sole Source ◽  
The Other ◽  
Cell Free Extract ◽  
Isolation And Identification

Bacillus cereusPN24 was isolated from soil by a conventional enrichment culture method using eugenol as a sole source of carbon and energy. The organism also utilized eugenol, 4-vinyl guaiacol, vanillin, vanillic acid and protocatechuic acid as growth substrates. The organism degraded eugenol to protocatechuic acid, which was further metabolized by aβ-ketoadipate pathway. On the other hand, the intermediate of the eugenol-degrading pathway, such as ferulic acid was not detected in the culture medium as an intermediate, as evidenced by isolation and identification of metabolites and enzyme activities in the cell-free extract. Such a bacterial strain could be used for phenolic environmental clean-up given optimal nutrient conditions.

scholarly journals MOLECULAR IDENTIFICATION OF YEAST OF THE PULQUE BY PCR-DGGE, A TRADITIONAL MEXICANBEVERAGE

2015 ◽  
Vol 3 (3) ◽  
pp. 1-15
Author(s):  
Marcial-Quino J. ◽  
Garcia-Ocón B. ◽  
Mendoza-Espinoza J.A. ◽  
Gómez-Manzo S. ◽  
Sierra-Palacios E
Keyword(s):  
Gel Electrophoresis ◽  
Fermentation Process ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Rapid Identification ◽  
Rrna Gene ◽  
Beverage Samples ◽  
D2 Domain ◽  
Gradient Gel Electrophoresis ◽  
26S Rrna

Currently it is well known that yeasts play an essential role in the production of different beverages. In this paper, were identified some of the yeasts involved in the fermentation process of the pulque, a Mexican traditional beverage. Samples were collected from different regions of Mexico and yeasts were detected directly from samples without cultivation. Identifying the yeasts was obtained using amplification the D1/D2 domain of the 26S rRNA gene and Denaturing Gradient Gel Electrophoresis (DGGE). The results of DGGE showed different profiles of bands in each of the analyzed samples, indicating the presence of several species of yeast, which was also confirmed by sequencing of the bands corresponding to the domain D1/D2, succeeded in identifying five species of yeasts. The results obtained in this work demonstrated that the technique used for identification of yeasts of pulque was efficient. Besides, the optimization of this method could also allow rapid identification of yeasts and help understand the role of these in the fermentation process of this beverage, as well as the isolation of strains of interest for biotechnological purposes such as production of ethanol or metabolites with nutraceutical activity.

scholarly journals Impact of Biochar Application to Soil on the Root-Associated Bacterial Community Structure of Fully Developed Greenhouse Pepper Plants

2011 ◽  
Vol 77 (14) ◽  
pp. 4924-4930 ◽  
Author(s):  
Max Kolton ◽  
Yael Meller Harel ◽  
Zohar Pasternak ◽  
Ellen R. Graber ◽  
Yigal Elad ◽  
...  
Keyword(s):  
Bacterial Community ◽  
16S Rrna ◽  
Relative Abundance ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Bacterial Community Composition ◽  
Systemic Resistance ◽  
Rrna Gene ◽  
Molecular Fingerprinting ◽  
Content Type ◽  
Biochar Amendment

ABSTRACTAdding biochar to soil has environmental and agricultural potential due to its long-term carbon sequestration capacity and its ability to improve crop productivity. Recent studies have demonstrated that soil-applied biochar promotes the systemic resistance of plants to several prominent foliar pathogens. One potential mechanism for this phenomenon is root-associated microbial elicitors whose presence is somehow augmented in the biochar-amended soils. The objective of this study was to assess the effect of biochar amendment on the root-associated bacterial community composition of mature sweet pepper (Capsicum annuumL.) plants. Molecular fingerprinting (denaturing gradient gel electrophoresis and terminal restriction fragment length polymorphism) of 16S rRNA gene fragments showed a clear differentiation between the root-associated bacterial community structures of biochar-amended and control plants. The pyrosequencing of 16S rRNA amplicons from the rhizoplane of both treatments generated a total of 20,142 sequences, 92 to 95% of which were affiliated with theProteobacteria,Bacteroidetes,Actinobacteria, andFirmicutesphyla. The relative abundance of members of theBacteroidetesphylum increased from 12 to 30% as a result of biochar amendment, while that of theProteobacteriadecreased from 71 to 47%. TheBacteroidetes-affiliatedFlavobacteriumwas the strongest biochar-induced genus. The relative abundance of this group increased from 4.2% of total root-associated operational taxonomic units (OTUs) in control samples to 19.6% in biochar-amended samples. Additional biochar-induced genera included chitin and cellulose degraders (ChitinophagaandCellvibrio, respectively) and aromatic compound degraders (HydrogenophagaandDechloromonas). We hypothesize that these biochar-augmented genera may be at least partially responsible for the beneficial effect of biochar amendment on plant growth and viability.

scholarly journals Effects of Wildfire and Harvest Disturbances on Forest Soil Bacterial Communities

2007 ◽  
Vol 74 (1) ◽  
pp. 216-224 ◽  
Author(s):  
Nancy R. Smith ◽  
Barbara E. Kishchuk ◽  
William W. Mohn
Keyword(s):  
Microbial Biomass ◽  
Microbial Communities ◽  
Community Composition ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Microbial Biomass Carbon ◽  
Bacterial Community Composition ◽  
Soil Microbial Communities ◽  
Rrna Gene ◽  
Microbial Biomass Nitrogen ◽  
Soil Microbial

ABSTRACT Wildfires and harvesting are important disturbances to forest ecosystems, but their effects on soil microbial communities are not well characterized and have not previously been compared directly. This study was conducted at sites with similar soil, climatic, and other properties in a spruce-dominated boreal forest near Chisholm, Alberta, Canada. Soil microbial communities were assessed following four treatments: control, harvest, burn, and burn plus timber salvage (burn-salvage). Burn treatments were at sites affected by a large wildfire in May 2001, and the communities were sampled 1 year after the fire. Microbial biomass carbon decreased 18%, 74%, and 53% in the harvest, burn, and burn-salvage treatments, respectively. Microbial biomass nitrogen decreased 25% in the harvest treatment, but increased in the burn treatments, probably because of microbial assimilation of the increased amounts of available NH4 + and NO3 − due to burning. Bacterial community composition was analyzed by nonparametric ordination of molecular fingerprint data of 119 samples from both ribosomal intergenic spacer analysis (RISA) and rRNA gene denaturing gradient gel electrophoresis. On the basis of multiresponse permutation procedures, community composition was significantly different among all treatments, with the greatest differences between the two burned treatments versus the two unburned treatments. The sequencing of DNA bands from RISA fingerprints revealed distinct distributions of bacterial divisions among the treatments. Gamma- and Alphaproteobacteria were highly characteristic of the unburned treatments, while Betaproteobacteria and members of Bacillus were highly characteristic of the burned treatments. Wildfire had distinct and more pronounced effects on the soil microbial community than did harvesting.

scholarly journals Bacterial Diversity and Community in Regional Water Microbiota between Different Towns in World’s Longevity Township Jiaoling, China

Diversity ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 361
Author(s):  
Lei Wu ◽  
Xinqiang Xie ◽  
Jumei Zhang ◽  
Yu Ding ◽  
Qingping Wu
Keyword(s):  
16S Rrna ◽  
High Throughput Sequencing ◽  
The Other ◽  
Rrna Gene ◽  
Metabolic Characteristics ◽  
Kegg Pathways ◽  
Healthy Longevity ◽  
And Function ◽  
Regional Water

Healthy longevity is associated with many factors, however, the potential correlation between longevity and microbiota remains elusive. To address this, we explored environmental microbiota from one of the world’s longevity townships in China. We used 16S rRNA gene high-throughput sequencing to analyze the composition and function of water microbiota. The composition and diversity of water microbiota significantly differed between the towns. Lactobacillus, Streptococcus, Bacteroides, Faecalibacterium, and Stenotrophomonas were only dominant in Xinpu, a town with an exceptionally high centenarian population. Several biomarkers were identified, including Flavobacterium, Acinetobacter, Paracoccus, Lactobacillales, Psychrobacter, Bacteroides, Ruminococcaceae, and Faecalibacterium, and these shown to be responsible for the significant differences between towns. The main species contributing to the differences between towns were Cyanobacteria, Cupriavidus and Ralstonia. Based on KEGG pathways showed that the predicted metabolic characteristics of the water microbiota in Xinpu towns were significantly different to those of the other towns. The results revealed significant differences in the composition and diversity of water microbiota in the longevity township. These findings provide a foundation for further research on the role of water microbiota in healthy longevity.

Bacterial abundance, growth and community composition in oligotrophic, metal-rich running waters of Southern New Caledonia

2021 ◽  
Author(s):  
Chiaki Motegi ◽  
Yvan Bettarel ◽  
Aurélie Dufour ◽  
Xavier Mari ◽  
Christophe Migon ◽  
...  
Keyword(s):  
Community Composition ◽  
Denaturing Gradient Gel Electrophoresis ◽  
New Caledonia ◽  
Bacterial Community Composition ◽  
Growth Efficiency ◽  
Rrna Gene ◽  
Running Waters ◽  
High Coverage ◽  
Running Water ◽  
P Limitation

<p>The basic bacterial ecology and diversity was investigated in five running water systems of Southern New Caledonia. These running waters were characterized by potential P-limitation and high concentrations of Ni, Fe, Mn, Cr and Co. The low concentrations of dissolved organic carbon, bacterial and viral abundance, bacterial production and growth efficiency support the characterization of the running waters as oligotroph to ultraoligotroph. Despite these similarities, there were strong differences (<50% similarity) in bacterial community composition between some habitats based on 16S rRNA gene and denaturing gradient gel electrophoresis (DGGE) fingerprints. The high coverage of sequenced DGGE bands found for <em>Betaproteobacteria</em> is typical for freshwater systems, however, we found also a strong representation of <em>Gammaproteobacteria</em>. Indeed the three bands found at all stations were related to <em>Limnohabitans</em> (<em>Comamonadaceae</em>) and <em>Alteromonadaceae</em>. Strong differences were also found between the free-living and the attached bacterial fraction with <em>Gammaproteobacteria </em>dominating in two systems. A higher representation of <em>Gammaproteobacteria </em>seems typical for metal-rich freshwater habitats. Consistent with fresh water habitats, majority of phylotypes detected in the sediment was affiliated to proteobacteria. Also, none of the sequences showed a 100% identity with data bases, and 10 of the 22 and 2 of the 23 sequences had similarities higher than 97% in the freshwater and sediment. This could indicate specific adaptations of the community composition either due to the high metal concentrations or due to the geographical isolation of the New Caledonia. </p>

scholarly journals Spatial and Temporal Patterns in the Microbial Diversity of a Meromictic Soda Lake in Washington State

2008 ◽  
Vol 74 (15) ◽  
pp. 4877-4888 ◽  
Author(s):  
Pedro A. Dimitriu ◽  
Holly C. Pinkart ◽  
Brent M. Peyton ◽  
Melanie R. Mormile
Keyword(s):  
16S Rrna ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Bacterial Community Composition ◽  
Soda Lake ◽  
Community Diversity ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Most Probable Number ◽  
Rrna Gene ◽  
Probable Number

ABSTRACT The microbial community diversity and composition of meromictic Soap Lake were studied using culture-dependent and culture-independent approaches. The water column and sediments were sampled monthly for a year. Denaturing gradient gel electrophoresis of bacterial and archaeal 16S rRNA genes showed an increase in diversity with depth for both groups. Late-summer samples harbored the highest prokaryotic diversity, and the bacteria exhibited less seasonal variability than the archaea. Most-probable-number assays targeting anaerobic microbial guilds were performed to compare summer and fall samples. In both seasons, the anoxic samples appeared to be dominated by lactate-oxidizing sulfate-reducing prokaryotes. High numbers of lactate- and acetate-oxidizing iron-reducing bacteria, as well as fermentative microorganisms, were also found, whereas the numbers of methanogens were low or methanogens were undetectable. The bacterial community composition of summer and fall samples was also assessed by constructing 16S rRNA gene clone libraries. A total of 508 sequences represented an estimated >1,100 unique operational taxonomic units, most of which were from the monimolimnion, and the summer samples were more diverse than the fall samples (Chao1 = 530 and Chao1 = 295, respectively). For both seasons, the mixolimnion sequences were dominated by Gammaproteobacteria, and the chemocline and monimolimnion libraries were dominated by members of the low-G+C-content group, followed by the Cytophaga-Flexibacter-Bacteroides (CFB) group; the mixolimnion sediments contained sequences related to uncultured members of the Chloroflexi and the CFB group. Community overlap and phylogenetic analyses, however, not only demonstrated that there was a high degree of spatial turnover but also suggested that there was a degree of temporal variability due to differences in the members and structures of the communities.

Bacterial diversity within the planktonic community of an artesian water supply

2006 ◽  
Vol 52 (3) ◽  
pp. 246-259 ◽  
Author(s):  
Christopher L Ball ◽  
Ronald L Crawford
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Water Supply ◽  
Bacterial Diversity ◽  
Cultured Cells ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Enrichment Culture ◽  
Rrna Gene ◽  
Artesian Water ◽  
Planktonic Community

Culture and molecular methods were used to describe the planktonic bacterial diversity of an artesian water supply in rural Latah County, Idaho, within the drainage of a small perennial stream, Thorn Creek. The surrounding depth to groundwater at this location is thought to be significant (>100 m), and this transitional zone (basalt–granite) of the Palouse aquifer system is little studied. The water produced by this artesian source is consistent even in years of drought and is of high quality, both mineralogically and microbiologically. A culture-based analysis using 30 media types and four incubation temperatures demonstrated that several metabolic types were present in the water. 16S rRNA gene fragments amplified from the DNA of pooled cultured cells and from the DNA extracted from 1 L of the source water were compared using denaturing gradient gel electrophoresis. The results indicated that the two DNA samples did not have similar 16S rRNA gene compositions and that several uncultured phyla were present in the community DNA sample. These results indicated that large-scale culturing did not accurately represent the structure planktonic community. 16S rRNA gene sequences from 17 different genera were obtained from the community DNA sample; the most abundant were similar to Rhodoferax, Rhodobacter, and Polaromonas species. Sequences related to the Proteo bacteria, Bacteroidetes/Chlorobi, Firmicutes, and Acidobacterium/Fibrobacter divisions were also detected.Key words: artesian spring, bacterial diversity, DGGE, 16S rRNA, enrichment culture.

scholarly journals Characterization of incubation experiments and development of an enrichment culture capable of ammonium oxidation under iron-reducing conditions

2015 ◽  
Vol 12 (3) ◽  
pp. 769-779 ◽  
Author(s):  
S. Huang ◽  
P. R. Jaffé
Keyword(s):  
Iron Reduction ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Enrichment Culture ◽  
Nitrogen Loss ◽  
Pcr Analysis ◽  
Rrna Gene ◽  
Ammonium Oxidation ◽  
Soil Slurry ◽  
Riparian Wetland ◽  
Incubation Experiments

Abstract. Incubation experiments were conducted using soil samples from a forested riparian wetland where we have previously observed anaerobic ammonium oxidation coupled to iron reduction. Production of both nitrite and ferrous iron was measured repeatedly during incubations when the soil slurry was supplied with either ferrihydrite or goethite and ammonium chloride. Significant changes in the microbial community were observed after 180 days of incubation as well as in a continuous flow membrane reactor, using 16S rRNA gene PCR-denaturing gradient gel electrophoresis, 454 pyrosequencing, and real-time quantitative PCR analysis. We be Acidimicrobiaceae bacterium A6), belonging to the Acidimicrobiaceae family, whose closest cultivated relative is Ferrimicrobium acidiphilum (with 92% identity) and Acidimicrobium ferrooxidans (with 90% identity), might play a key role in this anaerobic biological process that uses ferric iron as an electron acceptor while oxidizing ammonium to nitrite. After ammonium was oxidized to nitrite, nitrogen loss proceeded via denitrification and/or anammox.

scholarly journals Isolation and Identification of Potentially Pathogenic Microorganisms Associated with Dental Caries in Human Teeth Biofilms

2020 ◽  
Vol 8 (10) ◽  
pp. 1596
Author(s):  
Xiuqin Chen ◽  
Eric Banan-Mwine Daliri ◽  
Ramachandran Chelliah ◽  
Deog-Hwan Oh
Keyword(s):  
Dental Caries ◽  
Fermented Food ◽  
Rrna Gene ◽  
Fermented Foods ◽  
Isolation And Identification ◽  
Human Teeth ◽  
Streptococcus Anginosus ◽  
Gene Sequence Analysis ◽  
First Time

Dental caries is attributed to the predominance of cariogenic microorganisms. Cariogenic microorganisms are pathological factors leading to acidification of the oral microenvironment, which is related to the initiation and progression of caries. The accepted cariogenic microorganism is Streptococcus mutans (S. mutans). However, studies have found that caries could occur in the absence of S. mutans. This study aimed to assess the presence of potentially cariogenic microorganisms in human teeth biofilm. The microorganisms were isolated from human mouth and freshly extracted human maxillary incisors extracted for reasons of caries. The isolates were sorted based on their acidogenic and aciduric properties, and the S. mutans was used as the reference strain. Four potentially cariogenic strains were selected. The selected strains were identified as Streptococcus salivarius (S. salivarius), Streptococcus anginosus (S. anginosus), Leuconostoc mesenteroides (L. mesenteroides), and Lactobacillus sakei (L. sakei) through morphological analysis followed by 16S rRNA gene sequence analysis. The cariogenicity of isolates was analyzed. We show, for the first time, an association between L. sakei (present in fermented food) and dental caries. The data provide useful information on the role of lactic acid bacteria from fermented foods and oral commensal streptococci in dental caries.

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