Polyvinylpolypyrrolidone pvpp

Folin–Ciocalteu reagent (Sigma-Aldrich, Taufkirchen, Germany), gallic acid monohydrate (Sigma-Aldrich, Germany), sodium bicarbonate (Sigma-Aldrich, Germany), poly(vinylpolypyrrolidone) (PVPP) (Sigma-Aldrich, Germany), acetone (Sigma-Aldrich, Germany).

Pure standards of aroma compounds, namely, polyvinylpolypyrrolidone (PVPP) and 4-methyl-2-pentanol Methanol, were purchased from Sigma-Aldrich (St. Louis, MO, USA). β-d-glucolactone and n-octyl-β-d-glucopyranoside were purchased from Sangon Biotech (Shanghai, China). Rapidase® AR2000 commercial preparation with glycosidase side activities was purchased from DSM Oenology (Delft, The Netherlands). Methanol, dichloromethane, citric acid, and sodium phosphate dibasic dodecahydrate (analytical grade) were purchased from Beijing Chemical Works (Beijing, China). LC-MS grade acetonitrile, formic acid, and Methanol were purchased from Honeywell (Morristown, NJ, USA).

Syringaldazine (purity ≥ 98%), polyvinylpolypyrrolidone (PVPP) (purity ≥ 98%) and FeSO₄·7H₂O (purity ≥ 99%) were purchased from Sigma-Aldrich (Madrid, Spain). L-(·+)-tartaric acid (purity ≥ 99.5%), sodium hydroxide (purity ≥ 98%), sodium acetate (purity ≥ 99%), acetonitrile (purity ≥ 99%), methanol (purity ≥ 99%) and CuSO₄·5H₂O (purity ≥ 99%) were purchased from Panreac (Barcelona, Spain). Ethanol (96% vol.) was supplied by Fisher Scientific (Madrid, Spain). L-glutathione reduced (purity ≥ 98%) was purchased from Sigma-Aldrich (Madrid, Spain). trans-Caftaric acid (purity ≥ 95%) was purchased from Phytolab (Vestenbergsgreuth, Germany). Cellulose membranes of 3.5 KDa (6.4 mL/cm) were supplied by Spectrum Laboratories, Inc. (Rancho Dominguez, CA, USA). The equipment used was as follows: an Hpand and Entris II Series Analytical Balance (Sartorius, Goettingen, Germany), a UV-Vis Helios Alpha ™ spectrophotometer (Thermo Fisher Scientific Inc., Waltham, MA, USA), a Heraeus™ Primo™ centrifuge (Thermo Fisher Scientific Inc., Waltham, MA, USA), and an Agilent Series 1200 liquid chromatograph (Agilent, Germany) equipped with a photodiode array detector (G1315D) and a Zorbax Eclipse XDB C18 column (4.6 × 150 mm).

The external C6 volatile standards, including hexanal (98.0% purity), (E)-2-hexenal (98.0%), 1-hexanol (99.0%), (E)-2-hexen-1-ol (96.0%), (E)-3-hexen-1-ol (98.0%), (Z)-2-hexen-1-ol (96.0%), (Z)-3-hexen-1-ol (98.0%), ethyl hexanoate (99.0%), hexyl acetate (99.0%), (Z)-3-hexen-1-acetate (98.0%), and hexanoic acid (99.0%), were purchased from Sigma-Aldrich (St. Louis, MO, USA). The internal standard 4-methyl-2-pentanol was also purchased from Sigma-Aldrich, with a purity of 98.0%. Water used in this study was purified from a Milli-Q purification system (Millipore, Bedford, MA, USA). Polyvinylpolypyrrolidone (PVPP) was a product of Sigma-Aldrich. SYBR^® Premix Ex TaqTM and Spectrum™ Plant Total RNA Kit were purchased from TaKaRa Bio (Otsu, Shiga, Japan) and Sigma-Aldrich, respectively. A reverse transcription system kit was obtained from Promega (Madison, WI, USA). Other reagents used in this study were purchased from the Beijing Chemical Works (Beijing, China).

All the chemical standards used for identification and quantification of GLVs and polyvinylpolypyrrolidone (PVPP) were purchased from Sigma-Aldrich (Shanghai, China). NaCl was purchased from Beijing Chemical Works. SYBR^® Premix Ex TaqTM was purchased from TaKaRa Bio (Otsu, Shiga, Japan). The SpectrumTM Plant Total RNA Kit was from Sigma-Aldrich and Reverse Transcription System Kit was purchased from Promega (Madison, WI, USA).

DNA was isolated from the samples as previously described by Verweij et al. (2009) (link) for isolating DNA from faecal samples thought to contain Strongyloides larvae. Briefly, approximately 200 μg faeces or proglottid sample were first washed several times in distilled water to remove the formalin, then suspended in 200 μl of PBS containing 2% polyvinylpolypyrrolidone (PVPP; Sigma, Steinheim, Germany) and heated for 10 min at 100 °C. This was followed by incubation with sodium-dodecyl sulphate-proteinase K (2 h at 55 °C), before DNA was isolated using the QIAamp Tissue Kit spin columns (QIAgen, Hilden, Germany). DNA was eluted into 200 μl molecular-grade water and stored at −20 °C before use.