Effect of DNA extraction and sample preservation method on rumen bacterial population (original) (raw)
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The comparison of the bacterial profile of intracellular (iDNA) and extracellular DNA (eDNA) isolated from cow rumen content stored under different conditions was conducted. The influence of rumen fluid treatment (cheesecloth squeezed, centrifuged, filtered), storage temperature (RT, À80 C) and cryoprotectants (PBS-glycerol, ethanol) on quality and quantity parameters of extracted DNA was evaluated by bacterial DGGE analysis, real-time PCR quantification and metabarcoding approach using highthroughput sequencing. Samples clustered according to the type of extracted DNA due to considerable differences between iDNA and eDNA bacterial profiles, while storage temperature and cryoprotectants additives had little effect on sample clustering. The numbers of Firmicutes and Bacteroidetes were lower (P < 0.01) in eDNA samples. The qPCR indicated significantly higher amount of Firmicutes in iDNA sample frozen with glycerol (P < 0.01). Deep sequencing analysis of iDNA samples revealed the prevalence of Bacteroidetes and similarity of samples frozen with and without cryoprotectants, which differed from sample stored with ethanol at room temperature. Centrifugation and consequent filtration of rumen fluid subjected to the eDNA isolation procedure considerably changed the ratio of molecular operational taxonomic units (MOTUs) of Bacteroidetes and Firmicutes. Intracellular DNA extraction using bead-beating method from cheesecloth sieved rumen content mixed with PBS-glycerol and stored at À80 C was found as the optimal method to study ruminal bacterial profile.
Frontiers in microbiology, 2018
DNA based methods have been widely used to study the complexity of the rumen microbiota, and it is well known that the method of DNA extraction is a critical step in enabling accurate assessment of this complexity. Rumen fluid (RF) and fibrous content (FC) fractions differ substantially in terms of their physical nature and associated microorganisms. The aim of this study was therefore to assess the effect of four DNA extraction methods (RBB, PBB, FDSS, PQIAmini) differing in cell lysis and/or DNA recovery methods on the observed microbial diversity in RF and FC fractions using samples from four rumen cannulated dairy cows fed 100% grass silage (GS100), 67% GS and 33% maize silage (GS67MS33), 33% GS and 67% MS (GS33MS67), or 100% MS (MS100). An ANOVA statistical test was applied on DNA quality and yield measurements, and it was found that the DNA yield was significantly affected by extraction method ( < 0.001) and fraction ( < 0.001). The 260/280 ratio was not affected by extr...
PLOS ONE
The objective of this study was to investigate three storage methods and four storage times for rumen sampling in terms of quality and yield of extracted metagenomic DNA as well as the composition of the rumen bacterial community. One Nellore steer fitted with a ruminal silicone-type cannula was used as a donor of ruminal contents. The experiment comprised 11 experimental groups: pellet control (PC), lyophilized control (LC), P-20: pellet stored frozen at-20˚C for a period of 3, 6, and 12 months, P-80: pellet stored frozen at-80˚C for a period of 3, 6, and 12 months, and L-20: lyophilized sample stored frozen at-20˚C for a period of 3, 6, and 12 months. Metagenomic DNA concentrations were measured spectrophotometrically and fluorometrically and ion torrent sequencing was used to assess the bacterial community composition. The L-20 method could not maintain the yield of DNA during storage. In addition, the P-80 group showed a greater yield of metagenomic DNA than the other groups after 6 months of storage. Rumen samples stored as pellets (P-20 and P-80) resulted in lower richness Chao 1, ACE, and Shannon Wiener indices when compared to PC, while LC and PC were only different in richness ACE. The storage method and storage time influenced the proportions of 14 of 17 phyla identified by sequencing. In the P-20 group, the proportion of Cyanobacteria, Elusimicrobia, Fibrobacteres, Lentisphaerae, Proteobacteria, and Spirochaetes phyla identified was lower than 1%. In the P-80 group, there was an increase in the proportion of the Bacteroidetes phylum (p = 0.010); however, the proportion of Actinobacteria, Chloroflexi, SR1, Synergistetes, TM7, and WPS.2 phyla were unchanged compared to the PC group (p > 0.05). The class Clostridium was the most abundant in all stored groups and increased in its proportion, especially in the L-20 group. The rumen sample storage time significantly reduced the yield of metagenomic DNA extracted. Therefore, the
The objective of this study was to investigate three storage methods and four storage times for rumen sampling in terms of quality and yield of extracted metagenomic DNA as well as the composition of the rumen bacterial community. One Nellore steer fitted with a ruminal silicone type cannula was used as a donor of ruminal contents. The experiment comprised 11 experimental groups: pellet control (PC), lyophilized control (LC), P-20: pellet stored frozen at-20˚C for a period of 3, 6, and 12 months, P-80: pellet stored frozen at-80˚C for a period of 3, 6, and 12 months, and L-20: lyophilized sample stored frozen at-20˚C for a period of 3, 6, and 12 months. Metagenomic DNA concentrations were measured spectrophotometri-cally and fluorometrically and ion torrent sequencing was used to assess the bacterial community composition. The L-20 method could not maintain the yield of DNA during storage. In addition, the P-80 group showed a greater yield of metagenomic DNA than the other groups after 6 months of storage. Rumen samples stored as pellets (P-20 and P-80) resulted in lower richness Chao 1, ACE, and Shannon Wiener indices when compared to PC, while LC and PC were only different in richness ACE. The storage method and storage time influenced the proportions of 14 of 17 phyla identified by sequencing. In the P-20 group, the proportion of Cyanobacteria, Elusimicrobia, Fibrobacteres, Lentisphaerae, Proteobacteria, and Spirochaetes phyla identified was lower than 1%. In the P-80 group, there was an increase in the proportion of the Bacteroidetes phylum (p = 0.010); however, the proportion of Actino-bacteria, Chloroflexi, SR1, Synergistetes, TM7, and WPS.2 phyla were unchanged compared to the PC group (p > 0.05). The class Clostridium was the most abundant in all stored groups and increased in its proportion, especially in the L-20 group. The rumen sample storage time significantly reduced the yield of metagenomic DNA extracted. Therefore, the PLOS ONE | https://doi.org/10.1371/journal.pone. AV, et al. (2017) Studies on bacterial community composition are affected by the time and storage method of the rumen content. PLoS ONE 12(4): e0176701. https://doi.org/10.
Veterinary World, 2018
Background and Aim: A critical prerequisite for studying rumen microbial community by high throughput molecular biology methods is good quality community DNA. Current methods of extraction use kits designed for samples from the different origin for rumen. This puts stress on the development of a relevant manual method for DNA extraction. The objective of this study was to modify the existing methods of community DNA extraction and thereby systematic comparison of their efficiency based on DNA yield, purity, 16S rRNA gene sequencing, and identification to determine the optimal DNA extraction methods whose DNA products reflect targeted bacterial communities special to rumen. Materials and Methods: Enzymatic method, Chemical method, Enzymatic + Chemical method, and Enzymatic + Chemical + Physical method were modified toward evaluation of community DNA extraction from solid, squeezed, and liquid fractions of goat rumen digesta. Each method was assessed critically for nucleic acid yield and its quality. The methods resulting in high nucleic acid yield, optimal purity ratios with intact band on agarose gel electrophoresis were optimized further. Optimized methods were studied using standard polymerase chain reaction (PCR) with universal bacterial primers and 16S rRNA primers of targeted rumen bacteria. Methods denoting the presence of targeted rumen bacteria were assessed further with 16S rRNA gene sequencing and identification studies. It led toward methods efficacy estimation for molecular biology applications. Effect of rumen sample preservation on community DNA extraction was also studied. Their mean standard deviation values were calculated to understand sampling criticality. Results: Modified Chemical method (Cetrimonium bromide) and Enzymatic+Chemical+Physical (ECP) method (Lysozyme- Cetrimonium bromide-Sodium Dodecyl Sulfate-freeze-thaw) could extract 835 ng/μl and 161 ng/μl community DNA from 1.5 g solid and 2 ml squeezed rumen digesta with purity ratios of 1.8 (A260nm/A280nm) and 2.3 (A260nm/A230nm) respectively. Comparative analysis showed the better efficiency of ECP method and chemical method toward freshly squeezed rumen digesta and solid rumen digesta. However, sample preservation at -80°C for 1.5 months drastically affected the yield and purity ratios of community DNA. New protocol revealed targeted microbial community having Gram-positive as well as Gram-negative bacteria such as Prevotella ruminicola, Streptococcus lutetiensis, Ruminococcus flavefaciens, Fibrobacter succinogenes, and Selenomonas ruminantium. Conclusion: To date, this is the first report of modified methods wherein least chemicals and steps lead toward PCR and 16S rRNA gene sequencing quality community DNA extraction from goat rumen digesta. Detection of targeted rumen bacteria in solid and squeezed rumen digesta proves their strongest association with rumen fiber mat. It also marks the presence of distinct microbial communities in solid and squeezed rumen fractions that in turn differs the performance of each different method employed and yield of nucleic acid obtained. It also leaves a possibility of the presence of complex microbial consortia in squeezed rumen digesta whose DNA extraction methods need more attention. Finally, manual protocols of community DNA extraction may vary in different ruminant which suggests undertaking rigorous research in their establishment.
Low-cost sample preservation methods for high-throughput processing of rumen microbiomes
2022
BackgroundThe use of rumen microbial community (RMC) profiles to predict methane emissions has driven interest in ruminal DNA preservation and extraction protocols that can be processed cheaply while also maintaining or improving DNA quality for RMC profiling. Our standard approach for preserving rumen samples, as defined in the Global Rumen Census (GRC), requires time-consuming pre-processing steps of freeze drying and grinding prior to international transportation and DNA extraction. This impedes researchers unable to access sufficient funding or infrastructure. To circumvent these pre-processing steps, we investigated three methods of preserving rumen samples for subsequent DNA extraction, based on existing lysis buffers Tris-NaCl-EDTA-SDS (TNx2) and guanidine hydrochloride (GHx2), or 100% ethanol.ResultsRumen samples were collected via stomach intubation from 151 sheep at two time-points two weeks apart. Each sample was separated into four subsamples and preserved using the thre...
Molecular Biology Reports, 2018
Cost-effectiveness, quality, time-effectiveness and ease of the methodology are the most crucial factors in isolating quality DNA from wide variety of samples. Thus, research efforts focusing on the development of an efficient DNA extraction protocol is the need of the hour. The present study therefore, focuses on development of an efficient, rapid and free of inhibitory substances based methodology for extracting metagenomic DNA from diverse environmental samples viz. anaerobic biogas digesta, ruminant stomach, human feces, soil, and microbial starter cultures used for preparation of fermented food. PCR-DGGE based analysis and quality metagenomic library preparation, using DNA extraction methodology, validates the developed protocol. The developed protocol is cost effective, capable of isolating DNA from small sample size (100-1000 µl), time efficient (1.5-2.0 h protocol) and results in significantly higher DNA yield (4-8 times increased yield) when compared to previously available DNA extraction method and a commercial DNA extraction kit. The DNA extracted from the samples using different protocols was evaluated based on its ability to identify diverse microbial species using PCR-DGGE profiles targeting variable region within the 16S rRNA gene. The results of microbial community analysis revealed comparability of the developed protocol to commercial kits, in effectively identifying dominant representatives of the microbial community in different samples. Using the DNA extracted from the presented methodology, metagenomic libraries were prepared, which were found suitable for sequencing on Illumina platform.
BMC Research Notes, 2015
Background: The anaerobic digestion is one of the most spread renewable energy technology. The input biomasses included various environmental problematic wastes such as sludge coming from wastewater treatment plant (WWTP) and organic fraction of municipal solid waste (OFMSW). As biomolecular procedures have become important tools for the microbial characterisation of anaerobic samples coming from the reactors, it is crucial sampling and extracting properly DNA in order to employ such types of techniques. The current study is aimed to evaluate how freezing temperature and length of storage at −20 °C influence both the extracted DNA yield and microbial community quantifications from digested sludge samples collected at full-scale plants. Results: From WWTP sludge samples, we observed a reduction of DNA concentration comparing fresh and stored samples for 10 days at −20 °C (ANOVA test p < 0.0001), with an estimated DNA loss of approximately 65 % for such types of samples, however the methanogen communities can be assessed respecting the fresh conditions. From OFMSW sludge samples, we observed a reduction in extracted DNA (−90 %), after 120 frozen days, while microbial communities are determined respecting the fresh conditions within 2 months of frozen storage. Conclusions: The remarkable effect of frozen storage on sludge samples suggests as the better procedure to perform the DNA extraction from fresh sample. On the other hand it is not generally possible, so approximately 2 months of storage at −20 °C appears to be suitable time at which DNA concentrations remain sufficient to perform coherent microbial characterization through quantitative qRT-PCR.
Open Veterinary Journal, 2018
DNA is the prerequisite for life's inception that transfers hereditary information, past several years; various types of commercial kits are made available which vary depending on the type of the biological sample being used. The present study is focused on developing an improvised methodology for the isolation of genomic DNA from stored bovine blood samples. DNA was isolated by using the conventional Phenol: Chloroform: Isoamyl alcohol (PCI) method and Detergent method. The aim of the study was to make a comparative analysis and evaluation of these two methods to identify the one that gives a superior quality and quantity of genomic DNA. Total (n=48) each duplicate blood samples from three different buffalo(Bubalus bubalis) breeds Banni, Surti, Murrah, three zebu cattle (Bos indicus) breeds Kankerj, Gir, Sahiwal were collected from the jugular vein. The quantity, purity of the genomic DNA was assessed based on the total DNA yield, purity ratios, spectral profile, agarose gel electrophoresis analysis and polymerase chain reaction amplification of MC1R gene product without any inhibitors. The results of our study suggest that detergent method is also suitable for extraction of genomic DNA from the bovine blood and results were significant (*P>0.05). The total mean yield was found to be 329.05±11 μg/5ml for all six breeds while the PCI method was employed. The total mean yield of the gDNA for all six breeds was 406.6±43 μg/5ml of blood when the detergent method was used. One way ANOVA test showed that the total DNA yield varied depending on the isolation method used. The DNA yield obtained from the DG method was (***P< 0.001) significant as compared to the PCI method (**P<0.01).