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Role of Intestinal Microbiota in Ulcerative Colitis

Role of Intestinal Microbiota in Ulcerative Colitis

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(Bio‐Rad Labs, Hercules, California). The 9% polyamide gels were made with denatur<strong>in</strong>g gradients<br />

rang<strong>in</strong>g from 25% to 65%. The 100% denaturant solution conta<strong>in</strong>ed 40% formamide and 7M urea.<br />

Thirteen microlitres PCR products were mixed with 3 µL load<strong>in</strong>g dye before load<strong>in</strong>g. Gels were run<br />

<strong>in</strong> 1 x TAE at 60 °C for 16 h at 36 V, 28 mA, sta<strong>in</strong>ed with ethidium bromide for 15 m<strong>in</strong>, desta<strong>in</strong>ed<br />

for 20 m<strong>in</strong>, and viewed by UV‐B trans illum<strong>in</strong>ation at 302 nm (Bio‐Rad). The BioNumerics s<strong>of</strong>tware,<br />

version 4.60 (Applied Maths, S<strong>in</strong>t‐Martens‐Latem, Belgium) was used for identification <strong>of</strong> bands<br />

and normalization <strong>of</strong> band patterns from DGGE gels. DGGE gels were normalized by an assigned<br />

marker (developed <strong>in</strong> our laboratory). A cluster analysis was performed based on Dice coefficient<br />

<strong>of</strong> similarity (weighted) with the unweighted pair group method with arithmetic averages<br />

cluster<strong>in</strong>g algorithm.<br />

Quantitative PCR assay conditions<br />

QPCR was performed on an ABI Prism 7900 HT from Applied Biosystems. The amplification<br />

reactions were carried out <strong>in</strong> a total volume <strong>of</strong> 11 μL conta<strong>in</strong><strong>in</strong>g; 5.50 μL (EXPRESS SYBR ®<br />

GreenER TM qPCR SuperMix, ROX, Invitrogen), primers (each at 200 nM concentration) (Eur<strong>of</strong><strong>in</strong>s<br />

MWG Synthesis GmbH), 2 μL template DNA, and Nuclease‐free water (Qiagen) purified for PCR.<br />

The amplification program consisted <strong>of</strong> one cycle at 50°C for 2 m<strong>in</strong>; one cycle at 95°C for 10 m<strong>in</strong>;<br />

40 cycles at 95°C for 15 sec and 60°C for 1 m<strong>in</strong>; and f<strong>in</strong>ally one cycle <strong>of</strong> melt<strong>in</strong>g curve analysis for<br />

amplicon specificity at 95°C for 15 sec, 60°C for 20 sec and <strong>in</strong>creas<strong>in</strong>g ramp rate by 1.92°C/m<strong>in</strong><br />

until 95° for 15 sec. DNA (5 ng/µl) from the duplicate DNA extractions <strong>of</strong> each sample was used for<br />

the qPCR.<br />

Quantitative PCR primer and data handl<strong>in</strong>g<br />

The primers specific to regions <strong>of</strong> the 16S rRNA genes <strong>of</strong> selected bacterial taxa are listed <strong>in</strong> Table<br />

1. The relative quantities <strong>of</strong> gene targets encod<strong>in</strong>g gene sequences <strong>of</strong> the bacterial taxa were<br />

calculated us<strong>in</strong>g 2 DeltaCt , assum<strong>in</strong>g primer efficiency at 1.0. Delta Ct is the Ct‐values <strong>of</strong> the bacterial<br />

target normalized aga<strong>in</strong>st Ct‐values <strong>of</strong> the total bacterial population <strong>in</strong> a sample. Ct is the<br />

threshold cycle calculated by the ABI s<strong>of</strong>tware (SDS version 2.2; Applied Biosystems, Foster City,<br />

California, USA) as the PCR cycle, where amplifications signal exceeds the selected threshold value,<br />

also set by the ABI s<strong>of</strong>tware. Prior to the quantification <strong>of</strong> the M‐SHIME samples, standard curves<br />

were created us<strong>in</strong>g serial 10‐fold dilutions <strong>of</strong> bacterial DNA extracted from one <strong>of</strong> the M‐SHIME<br />

7

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