Amx 600 spectrometer

¹H-NMR spectra were made on a Bruker AMX600 spectrometer operating at 500.13 MHz at 65 °C. Typically, 64 scans were recorded with an interpulse delay of 5 s (T1 values for the resonance of the anomeric protons of κ- and ι-carrageenan are shorter than 1.5 s). Sample preparation for the ¹H-NMR experiments involved dissolving the carrageenan sample (5 mg mL⁻¹) at 80 °C in D2O containing 1 mMTSP (3-(trimethylsilyl) propionic-2,2,3,3-d4 acid sodium salt) and 20 mM Na₂HPO₄, followed by sonication (Branson 2510) for three periods of 1 h. Chemical shifts (δ) are referred to internal TSP standard (δ = 0 ppm for 1H) according to Knutsen and Grasdalen (1987) [33 (link)]. The chemical shift data described by Van de Velde et al. (2002a) [34 (link)] were used to assign the ¹H-NMR spectra.

¹H NMR spectra were recorded on a Bruker AMX 600 spectrometer (Billerica, MA, USA) at 600 MHz. Mass spectra were determined on a Bruker AutoFLEX III Smartbeam TOF MALDI-TOF mass spectrometer. The instrument was operated in positive ion mode with a 337 nm nitrogen laser and the data were obtained by using α-cyano-4-hydroxycinnamic acid as the matrix. UV-visible absorption spectra were measured on a PerkinElmer Lambda 950 spectrophotometer (Waltham, MA, USA) operated over a wavelength range of 300–1200 nm. Fluorescence spectra were measured on a Varian Eclipse spectrofluorometer (Palo Alto, CA, USA). Fourier transform infrafred (FT-IR) spectra were recorded on an Alpha II (100 FT-IR) spectrometer (Bruker, Billerica, MA, USA) with a universal attenuated total reflectance (ATR) sampling accessory. All the data were obtained from neat particles. The pH values for the buffer solutions were measured using an 86555 Laboratory Benchtop digital pH meter (AZ Instrument Corp., Taichung City, China).

NMR spectra were recorded by Bruker AMX 600 spectrometer (Bruker Italia, Milan, Italy) equipped with an inverse TCI Cryoprobe. MS analysis was performed on a micro-QToF mass spectrometer (Water Spa, Milan, Italy) equipped with an elettrospray ionization (ESI) source (negative mode) and coupled with a Waters Alliance HPLC system. High-resolution mass spectra were acquired on a Q-Exactive Hybrid Quadrupole-Orbitrap mass spectrometer (Thermo Scientific). All HPLC analyses were performed on a JASCO system (PU-2089 Plus-Quaternary gradient pump equipped with a Jasco MD-2018 Plus photodiode array detector) (Jasco, Tokyo, Japan). Fluorescence measurements were recorded by a JASCO Fluorometer FP-8300 equipped with Fluorescence Microplate Reader and an AxioVertA1 (Carl Zeiss, Germany) epifluorescence microscopy with coupled-device camera interfaced with the Axio Vision acquisition/image analysis software. RNA concentration was assayed by a ND-1000 spectrophotometer (NanoDrop) and quality assessed by the Agilent 2100 Bioanalyzer with Agilent RNA 6000 nano kit (Agilent Technologies, Santa Clara, CA, USA). RNA cluster generation and sequencing was carried out by Illumina HiSeq 2500 System (Illumina).

ABPS was prepared and characterized as previously reported (Chen et al., 2005 (link)) and kindly provided by Prof. Gengyuan Tian (Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences). Briefly, the dried roots of A. bidentata were sliced into sheets and extracted with distilled water at room temperature overnight. The water extract was filtered and concentrated under vacuum, and supernatants were precipitated with acetone at 4°C overnight. The crude polysaccharides were deproteinized, filtered, concentrated, and loaded on a DEAE-Cellulose 52 column and Sephadex G-50 column to obtain ABPS. The homogeneity and molecular weight of ABPS were determined by high-performance gel permeation chromatography (HPGPC) with TSK-2000SW columns. The monosaccharide composition of ABPS was determined by high-performance liquid chromatography (HPLC) with a carbohydrate analysis column. Infrared spectral analysis was conducted on a Bio-Rad FTS185 spectrophotometer, and the ¹³C NMR spectra of ABPS were recorded with a Bruker AMX-600 spectrometer.
ABPS consisted of fructose and glucose in a molar ratio of 8:1, with a mean molecular weight of 1,400 Da. ABPS has a main chain of (2→1)-linked-β-D-Fruf and a branch chain of (2→6)-linked-β-D-Fruf with (2→1,6)-linked-β-D-Fruf residues and terminated with fructose and glucose residue (Chen et al., 2005 (link)).