scholarly journals Denaturing Gradient Gel Electrophoresis Analysis of 16S Ribosomal DNA Amplicons To Monitor Changes in Fecal Bacterial Populations of Weaning Pigs after Introduction of Lactobacillus reuteri Strain MM53

2000 ◽  
Vol 66 (11) ◽  
pp. 4705-4714 ◽  
Author(s):  
Joyce M. Simpson ◽  
Vance J. McCracken ◽  
H. Rex Gaskins ◽  
Roderick I. Mackie

ABSTRACT The diversity and stability of the fecal bacterial microbiota in weaning pigs was studied after introduction of an exogenousLactobacillus reuteri strain, MM53, using a combination of cultivation and techniques based on genes encoding 16S rRNA (16S rDNA). Piglets (n = 9) were assigned to three treatment groups (control, daily dosed, and 4th-day dosed), and fresh fecal samples were collected daily. Dosed animals received 2.5 × 1010 CFU of antibiotic-resistant L. reuteriMM53 daily or every 4th day. Mean Lactobacillus counts for the three groups ranged from 1 × 109 to 4 × 109 CFU/g of feces. Enumeration of strain L. reuteri MM53 on MRS agar (Difco) plates containing streptomycin and rifampin showed that the introduced strain fluctuated between 8 × 103 and 5 × 106 CFU/g of feces in the two dosed groups. Denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rDNA fragments, with primers specific for variable regions 1 and 3 (V1 and V3), was used to profile complexity of fecal bacterial populations. Analysis of DGGE banding profiles indicated that each individual maintained a unique fecal bacterial population that was stable over time, suggesting a strong host influence. In addition, individual DGGE patterns could be separated into distinct time-dependent clusters. Primers designed specifically to restrict DGGE analysis to a select group of lactobacilli allowed examination of interspecies relationships and abundance. Based on relative band migration distance and sequence determination, L. reuteriwas distinguishable within the V1 region 16S rDNA gene patterns. Daily fluctuations in specific bands within these profiles were observed, which revealed an antagonistic relationship between L. reuteri MM53 (band V1-3) and another indigenousLactobacillus assemblage (band V1-6).

2003 ◽  
Vol 69 (11) ◽  
pp. 6801-6807 ◽  
Author(s):  
Isabel Lopez ◽  
Fernanda Ruiz-Larrea ◽  
Luca Cocolin ◽  
Erica Orr ◽  
Trevor Phister ◽  
...  

ABSTRACT Denaturing gradient gel electrophoresis (DGGE) of PCR-amplified ribosomal DNA (rDNA) is routinely used to compare levels of diversity of microbial communities and to monitor population dynamics. While using PCR-DGGE to examine the bacteria in wine fermentations, we noted that several commonly used PCR primers for amplifying bacterial 16S rDNA also coamplified yeast, fungal, or plant DNA present in samples. Unfortunately, amplification of nonbacterial DNA can result in a masking of bacterial populations in DGGE profiles. To surmount this problem, we developed two new primer sets for specific amplification of bacterial 16S rDNA in wine fermentation samples without amplification of eukaryotic DNA. One primer set, termed WLAB1 and WLAB2, amplified lactic acid bacteria, while another, termed WBAC1 and WBAC2, amplified both lactic acid bacterial and acetic acid bacterial populations found in wine. Primer specificity and efficacy were examined with DNA isolated from numerous bacterial, yeast, and fungal species commonly found in wine and must samples. Importantly, both primer sets effectively distinguished bacterial species in wine containing mixtures of yeast and bacteria.


2009 ◽  
Vol 55 (No. 10) ◽  
pp. 413-423 ◽  
Author(s):  
V. Valášková ◽  
P. Baldrian

In soil microbial ecology, the effects of environmental factors and their gradients, temporal changes or the response to specific experimental treatments of microbial communities can only be effectively analyzed using methods that address the structural differences among whole communities. Fingerprinting methods are the most appropriate technique for this task when multiple samples must be analyzed. Among the methods currently used to compare microbial communities based on nucleic acid sequences, the techniques based on differences in the melting properties of double-stranded molecules, denaturing gradient gel electrophoresis (DGGE) or temperature gradient gel electrophoresis (TGGE), are the most widely used. Their main advantage is that they provide the possibility to further analyze whole sequences contained in fingerprints using molecular methods. In addition to the analysis of microbial communities based on DNA extracted from soils, DGGE/TGGE can also be used for the assessment of the active part of the community based on the analysis of RNA-derived sequences or for the analysis of sequences of functional genes encoding for proteins involved in important soil processes.


Biologia ◽  
2012 ◽  
Vol 67 (4) ◽  
Author(s):  
Pullabhotla Sarma ◽  
Vadlamudi Srinivas ◽  
Kondreddy Anil ◽  
Appa Podile

AbstractWe made an attempt to isolate and purify metagenomic DNA from chitin enriched soil. In this communication we report a modified direct lysis method for soil DNA extraction including initial pre-lysis washing of sample, followed by a rapid polyvinylpyrrolidone-agarose-based purification and electroelution of DNA using Gene-capsule™ assembly. Rapidity was achieved using low molarity conducting media (sodium-borate buffer) for electrophoresis by reducing run time for both the gel electrophoresis and electroelution. Extracted DNA was sufficiently pure and of high quality, evidenced by amplification of 16S rDNA and chitinase genes by PCR. Metagenomic nature of the DNA was confirmed by running V3 (16S rDNA) region amplicons using denaturing gradient gel electrophoresis. This method requires 30 min for purification, and less than 2 h for complete execution of protocol and becomes the first report on the isolation of metagenomic DNA from soil naturally enriched for chitin.


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