, 2001; Tomsheck et al., 2010). The assays were conducted by removing a 2.5-cm-wide strip of agar from the mid-portion of a standard Petri plate of PDA, creating two isolated learn more halves of agar. The fungus was inoculated onto one semi-circular agar piece and incubated at 23 °C for 10 days to allow for optimum production of volatile compounds. Test pathogens were inoculated onto the semi-circular section of agar opposite the semi-circular section inoculated with Ut-1. The plate was then wrapped with a single piece of parafilm and incubated at 23 °C for 24 h. Growth
of filamentous fungi was quantitatively assessed based on multiple measurements of growth extending from the edge of the inoculum plugs comparable with corresponding controls as described by Strobel et al. (2001). All tests were conducted in triplicate. Analysis of gases in the air space above the culture grown for 12 days at 23 ± 2 °C on PDA was undertaken using the solid phase microextraction fiber technique (Strobel et al., 2001). First, a baked ‘Solid Phase Micro Extraction’ syringe (Supelco) consisting of 50/30 divinylbenzene/carburen Selleck Ivacaftor on polydimethylsiloxane on a stable
flex fiber was placed through a small hole drilled in the side of the Petri plate and exposed to the vapor phase for 45 min. The syringe was then inserted into the splitless injection port of a Hewlett Packard 6890 gas chromatograph containing a 30 m × 0.25 mm inner diameter ZB Wax capillary column with a film thickness of 0.50 μm. The column was programmed as follows: 30 °C for 2 min followed by and increase to 220 °C at 5 °C min−1. The carrier gas was ultrahigh-purity helium (local distributor) and Anacetrapib the initial column head pressure was 50 kPa. Before trapping the volatiles, the fiber was conditioned at 240 °C for 20 min under a flow of helium gas. A 30-s injection time was used to introduce
the sample fiber into the chromatograph. The gas chromatograph was interfaced to a Hewlett Packard 5973 mass-selective detector (mass spectrometer) operating at unit resolution. The spectrometer was scanned at 2.5 scans s−1 over a mass range of 35–360 a.m.u. Data acquisition and data processing were performed on the Hewlett Packard chemstation software system. Initial identification of the compounds produced by the endophyte was made via library comparison using the National Institute of Standards and Technology (NIST) database, and all chemical compounds described in this report use the NIST database chemical terminology. As far as possible, authenticity of each compound identified by GC/MS was reconfirmed by GC/MS of authentic standards. Standard compounds were obtained from Sigma-Aldrich and run in a comparable manner as the fungal samples.