scholarly journals amoAGene Abundances and Nitrification Potential Rates Suggest that Benthic Ammonia-Oxidizing Bacteria and Not Archaea Dominate N Cycling in the Colne Estuary, United Kingdom

2014 ◽  
Vol 81 (1) ◽  
pp. 159-165 ◽  
Author(s):  
Jialin Li ◽  
David B. Nedwell ◽  
Jessica Beddow ◽  
Alex J. Dumbrell ◽  
Boyd A. McKew ◽  
...  
Keyword(s):  
Denaturing Gradient Gel Electrophoresis ◽  
Dry Weight ◽  
Estuarine Sediments ◽  
Ammonia Oxidizer ◽  
Ammonia Oxidizing Bacteria ◽  
Content Type ◽  
Gene Abundance ◽  
Nitrification Potential ◽  
Gradient Gel Electrophoresis ◽  
Colne Estuary

ABSTRACTNitrification, mediated by ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA), is important in global nitrogen cycling. In estuaries where gradients of salinity and ammonia concentrations occur, there may be differential selections for ammonia-oxidizer populations. The aim of this study was to examine the activity, abundance, and diversity of AOA and AOB in surface oxic sediments of a highly nutrified estuary that exhibits gradients of salinity and ammonium. AOB and AOA communities were investigated by measuring ammonia monooxygenase (amoA) gene abundance and nitrification potentials both spatially and temporally. Nitrification potentials differed along the estuary and over time, with the greatest nitrification potentials occurring mid-estuary (8.2 μmol N grams dry weight [gdw]−1day−1in June, increasing to 37.4 μmol N gdw−1day−1in January). At the estuary head, the nitrification potential was 4.3 μmol N gdw−1day−1in June, increasing to 11.7 μmol N gdw−1day−1in January. At the estuary head and mouth, nitrification potentials fluctuated throughout the year. AOBamoAgene abundances were significantly greater (by 100-fold) than those of AOA both spatially and temporally.Nitrosomonasspp. were detected along the estuary by denaturing gradient gel electrophoresis (DGGE) band sequence analysis. In conclusion, AOB dominated over AOA in the estuarine sediments, with the ratio of AOB/AOAamoAgene abundance increasing from the upper (freshwater) to lower (marine) regions of the Colne estuary. These findings suggest that in this nutrified estuary, AOB (possiblyNitrosomonasspp.) were of major significance in nitrification.

scholarly journals Molecular Analysis of Ammonia-Oxidizing Bacteria of the β Subdivision of the Class Proteobacteria in Compost and Composted Materials

1999 ◽  
Vol 65 (2) ◽  
pp. 396-403 ◽  
Author(s):  
George A. Kowalchuk ◽  
Zinaida S. Naoumenko ◽  
Piet J. L. Derikx ◽  
Andreas Felske ◽  
John R. Stephen ◽  
...  
Keyword(s):  
Denaturing Gradient Gel Electrophoresis ◽  
Ammonia Oxidizer ◽  
Ammonia Oxidizing Bacteria ◽  
Nitrogen Transformations ◽  
Rt Pcr ◽  
Gene Encoding ◽  
Specific Pcr ◽  
Pcr Products ◽  
Gradient Gel Electrophoresis ◽  
Almost All

ABSTRACT Although the practice of composting animal wastes for use as biofertilizers has increased in recent years, little is known about the microorganisms responsible for the nitrogen transformations which occur in compost and during the composting process. Ammonia is the principle available nitrogenous compound in composting material, and the conversion of this compound to nitrite in the environment by chemolithotrophic ammonia-oxidizing bacteria is an essential step in nitrogen cycling. Therefore, the distribution of ammonia-oxidizing members of the β subdivision of the class Proteobacteriain a variety of composting materials was assessed by amplifying 16S ribosomal DNA (rDNA) and 16S rRNA by PCR and reverse transcriptase PCR (RT-PCR), respectively. The PCR and RT-PCR products were separated by denaturing gradient gel electrophoresis (DGGE) and were identified by hybridization with a hierarchical set of oligonucleotide probes designed to detect ammonia oxidizer-like sequence clusters in the genera Nitrosospira and Nitrosomonas. Ammonia oxidizer-like 16S rDNA was detected in almost all of the materials tested, including industrial and experimental composts, manure, and commercial biofertilizers. A comparison of the DGGE and hybridization results after specific PCR and RT-PCR suggested that not all of the different ammonia oxidizer groups detected in compost are equally active. amoA, the gene encoding the active-site-containing subunit of ammonia monooxygenase, was also targeted by PCR, and template concentrations were estimated by competitive PCR. Detection of ammonia-oxidizing bacteria in the composts tested suggested that such materials may not be biologically inert with respect to nitrification and that the fate of nitrogen during composting and compost storage may be affected by the presence of these organisms.

Seasonal variation in communities of ammonia-oxidizing bacteria based on polymerase chain reaction – denaturing gradient gel electrophoresis in a biofilm reactor for drinking water pretreatment

2008 ◽  
Vol 54 (5) ◽  
pp. 358-365 ◽  
Author(s):  
Xiao-Wen Zhang ◽  
Ying-Ying Qin ◽  
Hong-Qiang Ren ◽  
Dao-Tang Li ◽  
Hong Yang
Keyword(s):  
Drinking Water ◽  
Gel Electrophoresis ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Biofilm Reactor ◽  
Ammonia Oxidizer ◽  
Ammonia Oxidizing Bacteria ◽  
Clone Libraries ◽  
Community Shift ◽  
Water Pretreatment ◽  
Gradient Gel Electrophoresis

The diversity and variation of total and active ammonia-oxidizing bacteria in a full-scale aerated submerged biofilm reactor for drinking water pretreatment were characterized by clone libraries and denaturing gradient gel electrophoresis (DGGE) analysis of 16S rRNA and its gene during a whole year. Sequences obtained from clone libraries affiliated with the Nitrosomonas oligotropha lineage and the Nitrosomonas communis lineage. An uncultured subgroup of Nitrosomonas communis lineage was also detected. Seasonal variations in both total and active ammonia-oxidizing bacteria communities were observed in the DGGE profiles, but an RNA-based analysis reflected more obvious dynamic changes in ammonia-oxidizer community than a DNA-based approach. Statistical study based on canonical correspondence analysis showed that a community shift of active ammonia oxidizers was significantly influenced by temperature and pH, but no significant correlation was found between environmental variables and total ammonia-oxidizer community shift.

A comparitive study of ammonia-oxidizing bacteria in lab-scale industrial wastewater treatment reactors

2003 ◽  
Vol 48 (3) ◽  
pp. 17-24 ◽  
Author(s):  
A.K. Rowan ◽  
G. Moser ◽  
N. Gray ◽  
J.R. Snape ◽  
D. Fearnside ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Industrial Wastewater ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Direct Sequencing ◽  
Ammonia Oxidizing Bacteria ◽  
Industrial Wastewater Treatment ◽  
Phylogenetic Affiliation ◽  
Gradient Gel Electrophoresis ◽  
Nitrosococcus Mobilis ◽  
Ammonia Oxidising Bacteria

The diversity and community structure of the b-proteobacterial ammonia oxidising bacteria (AOB) in a range of different lab-scale industrial wastewater treatment reactors were compared. Three of the reactors treat waste from mixed domestic and industrial sources whereas the other reactor treats waste solely of industrial origin. PCR with AOB selective primers was combined with denaturing gradient gel electrophoresis to allow comparative analysis of the dominant AOB populations and the phylogenetic affiliation of the dominant AOB was determined by cloning and sequencing or direct sequencing of bands excised from DGGE gels. Different AOB were found within and between different reactors. All AOB sequences identified were grouped within the genus Nitrosomonas. Within the lab-scale reactors there appeared to be selection for a low diversity of AOB and predominance of a single AOB population. Furthermore, the industrial input in both effluents apparently selected for salt tolerant AOB, most closely related to Nitrosococcus mobilis and Nitrosomonas halophila.

scholarly journals Efficacy of Rifaximin Vaginal Tablets in Treatment of Bacterial Vaginosis: a Molecular Characterization of the Vaginal Microbiota

2012 ◽  
Vol 56 (8) ◽  
pp. 4062-4070 ◽  
Author(s):  
Federica Cruciani ◽  
Patrizia Brigidi ◽  
Fiorella Calanni ◽  
Vittoria Lauro ◽  
Raffaella Tacchi ◽  
...  
Keyword(s):  
Bacterial Vaginosis ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Vaginal Microbiota ◽  
Controlled Study ◽  
Double Blind ◽  
Content Type ◽  
Sexually Transmitted ◽  
Gradient Gel Electrophoresis ◽  
Adverse Pregnancy ◽  
The Impact

ABSTRACTBacterial vaginosis (BV) is a common vaginal disorder characterized by an alteration of the vaginal bacterial morphotypes, associated with sexually transmitted infections and adverse pregnancy outcomes. The purpose of the present study was to evaluate the impact of different doses of rifaximin vaginal tablets (100 mg/day for 5 days, 25 mg/day for 5 days, and 100 mg/day for 2 days) on the vaginal microbiota of 102 European patients with BV enrolled in a multicenter, double-blind, randomized, placebo-controlled study. An integrated molecular approach based on quantitative PCR (qPCR) and PCR-denaturing gradient gel electrophoresis (PCR-DGGE) was used to investigate the effects of vaginal tablets containing the antibiotic. An increase in members of the genusLactobacillusand a decrease in the BV-related bacterial groups after the antibiotic treatment were demonstrated by qPCR. PCR-DGGE profiles confirmed the capability of rifaximin to modulate the composition of the vaginal microbial communities and to reduce their complexity. This molecular analysis supported the clinical observation that rifaximin at 25 mg/day for 5 days represents an effective treatment to be used in future pivotal studies for the treatment of BV.

scholarly journals Microbial Ecology Dynamics during Rye and Wheat Sourdough Preparation

2013 ◽  
Vol 79 (24) ◽  
pp. 7827-7836 ◽  
Author(s):  
Danilo Ercolini ◽  
Erica Pontonio ◽  
Francesca De Filippis ◽  
Fabio Minervini ◽  
Antonietta La Storia ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Microbial Ecology ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Diversity Indices ◽  
Rrna Gene ◽  
Content Type ◽  
Gradient Gel Electrophoresis ◽  
Plate Counts ◽  
Relative Abundances

ABSTRACTThe bacterial ecology during rye and wheat sourdough preparation was described by 16S rRNA gene pyrosequencing. Viable plate counts of presumptive lactic acid bacteria, the ratio between lactic acid bacteria and yeasts, the rate of acidification, a permutation analysis based on biochemical and microbial features, the number of operational taxonomic units (OTUs), and diversity indices all together demonstrated the maturity of the sourdoughs during 5 to 7 days of propagation. Flours were mainly contaminated by metabolically active genera (Acinetobacter,Pantoea,Pseudomonas,Comamonas,Enterobacter,Erwinia, andSphingomonas) belonging to the phylumProteobacteriaorBacteroidetes(genusChryseobacterium). Their relative abundances varied with the flour. Soon after 1 day of propagation, this population was almost completely inhibited except for theEnterobacteriaceae. Although members of the phylumFirmicuteswere present at very low or intermediate relative abundances in the flours, they became dominant soon after 1 day of propagation. Lactic acid bacteria were almost exclusively representative of theFirmicutesby this time.Weissellaspp. were already dominant in rye flour and stably persisted, though they were later flanked by theLactobacillus sakeigroup. There was a succession of species during 10 days of propagation of wheat sourdoughs. The fluctuation between dominating and subdominating populations ofL. sakeigroup,Leuconostocspp.,Weissellaspp., andLactococcus lactiswas demonstrated. Other subdominant species such asLactobacillus plantarumwere detectable throughout propagation. As shown by PCR-denaturing gradient gel electrophoresis (PCR-DGGE) analysis,Saccharomyces cerevisiaedominated throughout the sourdough propagation. Notwithstanding variations due to environmental and technology determinants, the results of this study represent a clear example of how the microbial ecology evolves during sourdough preparation.

scholarly journals Heterogeneity of uidA gene in environmental Escherichia coli populations

2005 ◽  
Vol 3 (3) ◽  
pp. 297-304 ◽  
Author(s):  
Clarivel Lasalde ◽  
Roberto Rodriguez ◽  
Gary A. Toranzos ◽  
Henry H. Smith
Keyword(s):  
Escherichia Coli ◽  
Genetic Heterogeneity ◽  
Gel Electrophoresis ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Dry Weight ◽  
Source Tracking ◽  
Tropical Rain Forests ◽  
Rain Forests ◽  
E Coli ◽  
Gradient Gel Electrophoresis

Previous studies have shown that Escherichia coli can be isolated from non-polluted rivers and from bromeliad axilae in pristine areas of tropical rain forests. Finding E. coli in pristine environments is unusual because this bacterium is thought to only survive in the gut of warm-blooded animals and thus its presence should indicate recent fecal contamination. The aims of this study were 1) to determine if E. coli is part of the native soil microbiota in tropical rain forests and 2) to determine if genetic heterogeneity exists among E. coli populations. High concentrations of total coliforms (104–105 cells per 10 g of soil dry weight) and low concentrations of thermotolerant coliforms (101–102 cells per 10 g dry soil, the majority of these were found to be E. coli) were detected. PCR using uidA-specific primers was done on DNA purified from E. coli isolates and the resulting amplicons analysed by denaturing-gradient gel electrophoresis (DGGE). Out of several hundred isolates, mixtures of nine different amplicons were consistently observed. The different patterns of DGGE observed indicate that the E. coli populations in these pristine soils are genetically heterogeneous. Fecal and environmental E. coli isolates were also analysed by pulsed-field gel electrophoresis (PFGE) which showed high DNA sequence variation among the E. coli isolates. Because of these differences in the genomes, PFGE did not allow grouping of environmental versus human isolates of E. coli when compared side to side. The apparent genetic polymorphisms, as a result of genetic heterogeneity, observed in isolates from the same pristine site indicate that source tracking may be difficult to carry out using E. coli as the target organism.

scholarly journals Bacterial Chitinolytic Communities Respond to Chitin and pH Alteration in Soil

2012 ◽  
Vol 79 (1) ◽  
pp. 263-272 ◽  
Author(s):  
Anna M. Kielak ◽  
Mariana Silvia Cretoiu ◽  
Alexander V. Semenov ◽  
Søren J. Sørensen ◽  
Jan Dirk van Elsas
Keyword(s):  
16S Rrna ◽  
Bacterial Communities ◽  
Plant Pathogens ◽  
Structural Changes ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Acid Soil ◽  
Rrna Gene ◽  
Content Type ◽  
Soil Suppressiveness ◽  
Gradient Gel Electrophoresis

ABSTRACTChitin amendment is a promising soil management strategy that may enhance the suppressiveness of soil toward plant pathogens. However, we understand very little of the effects of added chitin, including the putative successions that take place in the degradative process. We performed an experiment in moderately acid soil in which the level of chitin, next to the pH, was altered. Examination of chitinase activities revealed fast responses to the added crude chitin, with peaks of enzymatic activity occurring on day 7. PCR-denaturing gradient gel electrophoresis (DGGE)-based analyses of 16S rRNA andchiAgenes showed structural changes of the phylogenetically and functionally based bacterial communities following chitin addition and pH alteration. Pyrosequencing analysis indicated (i) that the diversity ofchiAgene types in soil is enormous and (i) that differentchiAgene types are selected by the addition of chitin at different prevailing soil pH values. Interestingly, a major role of Gram-negative bacteria versus a minor one ofActinobacteriain the immediate response to the added chitin (based on 16S rRNA gene abundance andchiAgene types) was indicated. The results of this study enhance our understanding of the response of the soil bacterial communities to chitin and are of use for both the understanding of soil suppressiveness and the possible mining of soil for novel enzymes.

scholarly journals Changes in Bacterial Diversity Associated with Epithelial Tissue in the Beef Cow Rumen during the Transition to a High-Grain Diet

2011 ◽  
Vol 77 (16) ◽  
pp. 5770-5781 ◽  
Author(s):  
Yanhong Chen ◽  
Gregory B. Penner ◽  
Meiju Li ◽  
Masahito Oba ◽  
Le Luo Guan
Keyword(s):  
Bacterial Diversity ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Pcr Analysis ◽  
Control Group ◽  
Epithelial Tissue ◽  
Rrna Gene ◽  
Content Type ◽  
Beef Cow ◽  
Dietary Transition ◽  
Gradient Gel Electrophoresis

ABSTRACTOur understanding of the ruminal epithelial tissue-associated bacterial (defined as epimural bacteria in this study) community is limited. In this study, we aimed to determine whether diet influences the diversity of the epimural bacterial community in the bovine rumen. Twenty-four beef heifers were randomly assigned to either a rapid grain adaptation (RGA) treatment (n= 18) in which the heifers were allowed to adapt from a diet containing 97% hay to a diet containing 8% hay over 29 days or to the control group (n= 6), which was fed 97% hay. Rumen papillae were collected when the heifers were fed 97%, 25%, and 8% hay diets. PCR-denaturing gradient gel electrophoresis (DGGE) and quantitative real-time PCR analysis were used to characterize rumen epimural bacterial diversity and to estimate the total epimural bacterial population (copy numbers of the 16S rRNA gene). The epimural bacterial diversity from RGA heifers changed (P= 0.01) in response to the rapid dietary transition, whereas it was not affected in control heifers. A total of 88 PCR-DGGE bands were detected, and 44 were identified from phyla includingFirmicutes,Bacteroidetes, andProteobacteria. The bacteriaTreponemasp.,Ruminobactersp., andLachnospiraceaesp. were detected only when heifers were fed 25% and 8% hay diets, suggesting the presence of these bacteria is the result of adaptation to the high-grain diets. In addition, the total estimated population of rumen epimural bacteria was positively correlated with molar proportions of acetate, isobutyrate, and isovalerate, suggesting that they may play a role in volatile fatty acid metabolism in the rumen.

Nitrifier and denitrifier molecular operational taxonomic unit compositions from sites of a freshwater estuary of Chesapeake Bay

2009 ◽  
Vol 55 (3) ◽  
pp. 333-346 ◽  
Author(s):  
Caroline S. Fortunato ◽  
David B. Carlini ◽  
Evan Ewers ◽  
Karen L. Bushaw-Newton
Keyword(s):  
Organic Matter ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Organic Matter Content ◽  
Sequence Divergence ◽  
Operational Taxonomic Unit ◽  
Matter Content ◽  
Ammonia Oxidizing Bacteria ◽  
Overlying Water ◽  
Pcr Products ◽  
Gradient Gel Electrophoresis

Temporal and spatial changes in the molecular operational taxonomic unit (OTU) compositions of bacteria harboring genes for nitrification and denitrification were assessed using denaturing gradient gel electrophoresis (DGGE), clone-based DNA sequencing of selected PCR products, and analyses of ammonium and organic matter concentrations. Sediment, overlying water, and pore-water samples were taken from different vegetated sites of Jug Bay National Estuarine Research Reserve, Maryland, during spring, summer, and fall 2006. OTU richness and the diversities of nitrifiers and denitrifiers were assessed by the presence of bands on DGGE gels, both ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) were seasonally dependent. AOB OTU richness was highest in the summer when NOB richness was decreased, whereas NOB richness was highest in the spring when AOB richness was decreased. The OTU diversities of nitrifiers did not correlate with ammonium concentrations, organic matter concentrations, or the presence of vegetation. The OTU diversities of denitrifiers possessing either the nirK or nosZ genes were not seasonally dependent but were positively correlated with organic matter content (p = 0.0015, r2 = 0.27; p < 0.0001, r2 = 0.39, respectively). Additionally, the presence of vegetation significantly enhanced nosZ species richness (Wilcoxon/Kruskal–Wallis test, p < 0.008), but this trend was not seen for nirK OTU richness. Banding patterns for nirK OTUs were more similar within sites for each season compared with any of the other genes. Over all seasons, nirK OTU richness was highest and AOB and nosZ OTU richness were lowest (Wilcoxon/Kruskal–Wallis test, p < 0.0001). High levels of sequence divergence among cloned nirK PCR products indicate a broad diversity of nirK homologs in this freshwater estuary.

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