Determination of sulfate in algal polysaccharide samples: a step-by-step protocol using microplate reader

Torres, Priscila Bezerra; Nagai, Alice; Jara, Carmen Eusebia Palacios; Santos, Janaína Pires; Chow, Fungyi; Santos, Déborah Yara Alves Cursino dos

doi:10.1590/2675-2824069.21-010pbt

Cited by 10 publications

(7 citation statements)

References 9 publications

(13 reference statements)

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“…Measurement of [SO42-] in agar or agarose: BaCl2-gelatin turbidimetric method (Torres et al, 2021) was used to quantify sulfate content of gel materials. Sulfated agarose product or commercially available agarose or agar powder was dissolved in 0.5M HCl at a concentration of 5% (w/v) in 2mL screw-top microtubes with gasket (Fisher Scientific).…”

Section: Synthesis Of Abp-dextranmentioning

confidence: 99%

Displacement of extracellular chloride by sulfated glycosaminoglycans of the brain’s extracellular matrix

Normoyle

Staley

2022

Preprint

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GABA is the primary inhibitory neurotransmitter. Membrane currents evoked by GABAAreceptor activation have uniquely small driving forces: their reversal potential (EGABA) is very close to the resting membrane potential. As a consequence, GABAAcurrents can flow in either direction, depending on both the membrane potential and the local intra and extracellular concentrations of the primary permeant ion, chloride (Cl). Cytoplasmic Cl concentrations vary widely due to displacement of mobile Cl ions by relatively immobile anions. Here we describe new reporters of extracellular chloride (Cl-o) and demonstrate that Cl is displaced in the extracellular space by high and spatially heterogenous concentrations of sulfated glycosaminoglycans. The mean Cl-ois only half the canonical concentration, i.e. the Cl concentration in the cerebrospinal fluid. Cl-omicrodomains provide a mechanism to link the highly stable distribution of GAGs in the brain’s extracellular space to neuronal signal processing via the effects on the amplitude and direction of GABAAtransmembrane Cl currents.

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Section: Synthesis Of Abp-dextranmentioning

confidence: 99%

Displacement of extracellular chloride by sulfated glycosaminoglycans of the brain’s extracellular matrix

Normoyle

Staley

2022

Preprint

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“…A higher level of organic and inorganic sulfate contents was reported in study conducted on G. domingensis as 6.2 and 1.4% in dry mass, respectively (Torres et al, 2021). The alkali treatment decreased the sulfate content in agar and forming higher amounts of the gelinducing 3,6-anhydrogalactose units (Rhein-Knudsen et al, 2017).…”

mentioning

confidence: 84%

“…Comparing with the present study, the pH values of extracted agar from water-and alkali-pretreated groups were slightly lower because of different harvesting location and extraction condition. forms (Torres et al, 2021) and, however, it negatively affects the agar gelation and strength that properties mainly determine the target applications of agar products (Armisen, 1995). The total sulfate content and distinct features of organic and inorganic sulfate contents of water-and NaOH-pretreated agars were analyzed using standard calibration equation of sulfate ions.…”

Section: Ph Valuementioning

confidence: 99%

Yield optimization, physicochemical characterizations, and antioxidant properties of food grade agar from Gracilaria tenuistipitata of Cox's Bazar coast, Bangladesh

Mohibbullah

Talha

Baten

et al. 2023

Food Science & Nutrition

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The present study was aimed at investigating the optimization of extraction variables for food grade quality agar from Gracilaria tenuistipitata, so far, the first study on Bangladeshi seaweed. Water (native)‐ and NaOH (alkali)‐pretreated agars were comparatively analyzed by several physicochemical parameters. All extraction variables significantly affected the agar yield in both extraction conditions. Alkali‐pretreated agar provided a better yield (12–13% w/w) and gel strength (201 g/cm2) in extraction conditions as followed by 2% NaOH pretreatment at 30°C for 3 h, seaweed to water ratio at 1:150, and extraction temperature at 100°C for 2 h. Gelling and melting temperatures, color, and pH values of both agars were found to be comparable with commercial agar. Significantly higher sulfate contents including organic and inorganic and total carotenoids were reported in native (3.14% and 1.29 μg/mL) than that in alkali‐pretreated agar (1.27% and 0.62 μg/mL). FTIR spectrum demonstrated the purity of the agar as characterized by the stronger relative intensity with higher degree of conversion of L‐galactose 6‐sulfate to 3,6‐anhydrogalactose in alkali pretreatment group than that of native ones. Moreover, antioxidant activity (% DPPH scavenging) was observed and confirmed by IC50 values of 5.42 and 9.02 mg/mL in water‐ and alkali‐pretreated agars, respectively. The results suggested that agar from G. tenuistipitata with optimized alkali extraction conditions could promote cost‐effective yield with improved physicochemical characteristics and biofunctional values upon consumption by the consumers as food materials.

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“…The sulfate content of the NSG/SGFs was determined using K 2 SO 4 as a standard (0–0.2 mg/mL) [ 47 ]. Briefly, 1 mg of SGF was hydrolyzed in 250 µL of 0.5 mol/L HCl, vortexed, and the mixture was incubated for 3 h at 100 °C in a digital dry bath.…”

Section: Methodsmentioning

confidence: 99%

Depolymerized Fractions of Sulfated Galactans Extracted from Gracilaria fisheri and Their Antibacterial Activity against Vibrio parahaemolyticus and Vibrio harveyi

et al. 2022

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Various seaweed sulfated polysaccharides have been explored for antimicrobial application. This study aimed to evaluate the antibacterial activity of the native Gracilaria fisheri sulfated galactans (NSG) and depolymerized fractions against the marine pathogenic bacteria Vibrio parahaemolyticus and Vibrio harveyi. NSG was hydrolyzed in different concentrations of H2O2 to generate sulfated galactans degraded fractions (SGF). The molecular weight, structural characteristics, and physicochemical parameters of both NSG and SGF were determined. The results revealed that the high molecular weight NSG (228.33 kDa) was significantly degraded to SGFs of 115.76, 3.79, and 3.19 kDa by hydrolysis with 0.4, 2, and 10% H2O2, respectively. The Fourier transformed spectroscopy (FTIR) and 1H− and 13C−Nuclear magnetic resonance (NMR) analyses demonstrated that the polysaccharide chain structure of SGFs was not affected by H2O2 degradation, but alterations were detected at the peak positions of some functional groups. In vitro study showed that SGFs significantly exerted a stronger antibacterial activity against V. parahaemolyticus and V. harveyi than NSG, which might be due to the low molecular weight and higher sulfation properties of SGF. SGF disrupted the bacterial cell membrane, resulting in leakage of intracellular biological components, and subsequently, cell death. Taken together, this study provides a basis for the exploitation and utilization of low-molecular-weight sulfated galactans from G. fisheri to prevent and control the shrimp pathogens.

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Determination of sulfate in algal polysaccharide samples: a step-by-step protocol using microplate reader

Cited by 10 publications

References 9 publications

Displacement of extracellular chloride by sulfated glycosaminoglycans of the brain’s extracellular matrix

Displacement of extracellular chloride by sulfated glycosaminoglycans of the brain’s extracellular matrix

Yield optimization, physicochemical characterizations, and antioxidant properties of food grade agar from Gracilaria tenuistipitata of Cox's Bazar coast, Bangladesh

Depolymerized Fractions of Sulfated Galactans Extracted from Gracilaria fisheri and Their Antibacterial Activity against Vibrio parahaemolyticus and Vibrio harveyi

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