Falcon conical centrifuge tube

One hundred and fifty-one adult ticks, obtained from 33 camels (20 males and 13 females), were collected from 13 locations in Saudi Arabia between April 2017 and January 2020. The locations are indicated on the map shown in Figure-1. It was not possible to collect the same number of samples from each location as sampling was dependent on the availability of ticks in the region. Ticks were removed from camels by hand and stored in sterile 50 ml Falcon™ conical centrifuge tubes. Ticks were placed in separate tubes according to their attachment site on a camel. The tubes were stored at −20°C until whole tick DNA was extracted using a DNeasy Blood and Tissue Kit (Qiagen, Hilden, Germany), according to the manufacturer’s instructions. Extracted DNA was stored at −20°C until being used for polymerase chain reaction (PCR) amplification and sequencing.

Five genotypes from the switchgrass GWAS population were tested in a modified hydroponic node culture experiment. For each genotype, 20 nodal segments were sampled from plants that were grown in the greenhouse at Noble Research Institute, LLC. After sterilization and pre-treatment, half of the node samples from each genotype were cultured on plates following the “Node culture protocol”, and half were cultured in 50 ml Falcon Conical Centrifuge Tubes, with the bottom half soaked in 5 ml 1/4 MS liquid medium. Node samples from both treatments were cultured at 24 °C under 16 h photoperiod and 200 μmol m^− 2 s^− 1 light intensity. In another test experiment, 15–20 nodal segments (3 cm below and 3 cm above each node) were collected from six switchgrass genotypes each, and were directly cultured in a sterilized turface:sand:perlite (2:2:1) mixture, with each node completely buried (2 cm deep) in the medium. Similarly, 10–20 node samples from three switchgrass genotypes were directly cultured in Metro-Mix 360. All the newly-grown nodes were kept in greenhouse under the same high humidity conditions as described above for rooting.

The activity of endo-β-1,4-xylanases on azo-xylan was determined according to the protocol provided by Megazyme with minor alterations. In brief, a 1% solution of azo-xylan was prepared in milli-Q H₂O, 0.25 mL was transferred into a 15-mL Falcon™ conical centrifuge tube and pre-equilibrated in a ThermoMixer C set at 40 °C. Enzymes were diluted in 100 mM sodium acetate buffer (pH 5.0), 0.25 mL buffered enzyme preparation were added to the azo-xylan solution and thoroughly mixed. Tubes were incubated at 40 °C for 10 min, after which reactions were terminated by addition of 1.75 mL 96% (v/v) ethanol with vigorous stirring. Tubes were incubated at room temperature for 10 min and again thoroughly mixed. In the case of reaction blanks, ethanol was added prior to enzyme addition. Supernatants were recovered by centrifugation (3000 rpm for 10 min) and absorbance was analyzed spectrophotometrically at 590 nm. Activities were calculated with the Megazyme Mega-Calc™ using Aspergillus niger endo-β-xylanase as a reference.