From each group two were sacrificed on day 1 after infection (early time point) and two mice at day 3 (late time point). The control mouse was sacrificed on day three. Bioluminescence at the early time point was measured from alive animals, whereas at the late time point bioluminescence was additionally recorded from explanted lungs by direct injection of D-luciferin. Lungs were cut into small pieces and briefly washed in phosphate buffered saline. Excess liquid
was removed on paper tissues and the weight of lungs was determined. The complete lung from each animal was frozen in liquid nitrogen and ground to a fine selleck chemical powder. Approximately 100 mg of each powdered lung was used for DNA extraction via the MasterPure yeast DNA extraction kit (Epicentre Biotechnologies, Biozym Scientific GmbH, Hessisch Oldendorf, Germany) as described in the manufacturer’s protocol. As a slight
modification and for obtaining DNA of higher purity grade, an Selleckchem BKM120 ethanol precipitation step of the DNA was included. The amount of DNA extracted from the lung tissues was quantified LEE011 purchase by a NanoDrop spectrophotometer. All samples were diluted to 100 ng/μl and quantified again to confirm the DNA concentration of each sample. As a standard for quantification of the amount of fungal DNA among the total DNA extracted from lung tissues, A. fumigatus genomic DNA was isolated by the same procedure from a culture grown for 20 h on minimal medium containing glucose (50 mM) and peptone (0.5% w/v) as nutrient sources. The TaqMan quantitative real-time PCR approach used based on the standard operation procedure (SOP) described elsewhere http://www.sacmm.org/pdf/Determination%20of%20Tissue%20Fungal%20Burden%20utilizing%20Quantitative%20Real%20Time%20PCR.pdf. The TaqMan® Universal PCR Master Mix (Applied Biosystems, Darmstadt, Germany) was used in all approaches. In brief, the genomic DNA region coding for the 18S rRNA from A. fumigatus was used as the target for amplification and quantification of fungal
DNA. A specific probe containing a 6-FAM-phosphoramidit labeling at the 5′-end and a TAMRA labeling at the 3′-end was used for detection of the amplification products. Amplification was performed on a StepOnePlus Real-Time PCR system (Applied Biosystems) Glutamate dehydrogenase and data were evaluated by using the StepOne software version 2.0 (Applied Biosystems). The standard curve on genomic DNA from A. fumigatus was generated from three technical replicates, whereby each replicate contained 6 dilutions in the range between 100 and 3.125 ng per reaction (stability index of standard curve = 0.99). The amplification program consisted of an initial denaturation at 95°C for 10 min followed by 40 cycles with denaturation for 15 s at 95°C, annealing for 30 s at 54°C, and amplification for 30 s at 72°C. All DNA samples from lung tissues were measured from 3 dilutions (from 500 to 125 ng total DNA per reaction) in two technical replicates.