Step gradient alcohol precipitation for the purification of low molecular weight fucoidan from Sargassum siliquastrum and its UVB protective effects.

Ultraviolet B (UVB) can induce oxidative damage to outermost layers of skin causing suntans, sunburns, and, in severe cases, blisters leading to photoaging. Low molecular weight (MW) fucoidan is renowned for possessing enhanced antioxidant activities. The present study discloses the use of step gradient ethanol precipitation in refining fucoidan fractions (SSQC1-SSQC4) from Sargassum siliquastrum and evaluation of their UVB-protective effects in human HaCaT keratinocytes. Among the fractions, SSQC4 indicated the best bioactive effects. 1H NMR, FTIR, monosaccharide composition by HPAEC-PAD analysis, MW estimation by agarose gel electrophoresis were used to characterize the fractions. SSQC4 was comprising of fucoidan, with an estimated MW distribution of 8-25 kDa. Exposure of UVB increased intracellular ROS, DNA damage, loss of mitochondrial membrane potential, apoptotic body formation causing cell death through the mitochondria-mediated apoptosis pathway. SSQC4 treatment could dose-dependently attenuate the ROS levels and suppress mitochondria-mediated apoptosis in UVB exposed keratinocytes. SSQC4 treatment enhanced cellular antioxidant defense by increasing Nrf2 mediated HO-1 generation, which was identified as the cause of observed bioactivities. The safety and stability of SSQC4 could be further evaluated to promote its use as a bioactive natural ingredient in UV-protective cosmetics.

Rapid quantification of multi-components in alcohol precipitation liquid of Codonopsis Radix using near infrared spectroscopy (NIRS).

A near infrared spectroscopy (NIRS) approach was established for quality control of the alcohol precipitation liquid in the manufacture of Codonopsis Radix. By applying NIRS with multivariate analysis, it was possible to build variation into the calibration sample set, and the Plackett-Burman design, Box-Behnken design, and a concentrating-diluting method were used to obtain the sample set covered with sufficient fluctuation of process parameters and extended concentration information. NIR data were calibrated to predict the four quality indicators using partial least squares regression (PLSR). In the four calibration models, the root mean squares errors of prediction (RMSEPs) were 1.22 µg/ml, 10.5 µg/ml, 1.43 µg/ml, and 0.433% for lobetyolin, total flavonoids, pigments, and total solid contents, respectively. The results indicated that multi-components quantification of the alcohol precipitation liquid of Codonopsis Radix could be achieved with an NIRS-based method, which offers a useful tool for real-time release testing (RTRT) of intermediates in the manufacture of Codonopsis Radix.

Magnetic nanoparticles adapted for specific biomedical applications.

Magnetic nanoparticles (MNPs) are used in different biomedical applications, whereby each application requires specific particle properties. To fulfill these requirements, particle properties have to be optimized by means of variation of crystal structure, particle size, and size distribution. To this aim, improved aqueous precipitation procedures for magnetic iron oxide nanoparticle synthesis were developed. One procedure focused on the cyclic growth of MNPs without nucleation of new particle cores during precipitation. The second novel particle type are magnetic multicore nanoparticles, which consist of single cores of approximately 10 nm forming dense clusters in the size range from 40 to 80 nm. Their highest potential features these multicore particles in hyperthermia application. In our in vivo experiments, therapeutically suitable temperatures were reached after 20 s of heating for a particle concentration in the tumor of 1% and field parameters of H=24 kA/m and f=410 kHz. This review on our recent investigations for particle optimization demonstrates that tuning magnetic properties of MNPs can be obtained by the alteration of their structure, size, and size distribution. This can be realized by means of control of particle size during synthesis or subsequent size-dependent fractionation. The here-developed particles show high potential for biomedical applications.

Optimization of the fractional precipitation of paclitaxel from a Taxus chinensis cell culture using response surface methodology and its isolation by consecutive high-speed countercurrent chromatography.

A consecutive preparation method for the isolation and purification of paclitaxel from the Taxus Chinensis cell culture was developed in this study. The process involved alkaline Al2O3 chromatography, fractional precipitation, and high-speed countercurrent chromatography. The original cell culture materials were first extracted with methanol using ultrasound-assisted extraction, and then the extract (the content of paclitaxel is 1.5%) was separated by alkaline Al2O3 column chromatography. Subsequently, fractional precipitation was used to obtain paclitaxel. In particular, response surface methodology was used to optimize the factors of fractional precipitation (methanol concentration, material-to-solvent ratio, and precipitating time were optimized as 48.14%, 8.85 mg/mL, and 48.71 h, respectively) and the yield of fractional precipitation product was 30.64 ± 0.60 mg (the content of paclitaxel is 89.3%, 27.37 ± 0.54 mg) from a 100 mg fraction by Al2O3 column separation (the content of paclitaxel is 32.4%). Then, the product was used for further isolation by high-speed countercurrent chromatography. About 1.00 g paclitaxel (200 ± 2 mg in each loading) with a purity up to 99.61% was isolated from 1.25 g of fractional precipitation product with a solvent system of n-hexane/ethyl acetate/methanol/water (1.2:1.8:1.5:1.5, v/v/v/v) in one run of five consecutive sample loadings without exchanging a new solvent system.

Phosphorus recovery potential from a waste stream with high organic and nutrient contents via struvite precipitation.

Recovery of NH4(+)-N and PO(3-)-P via struvite precipitation (SP) was evaluated from liquor of thermally pretreated waste activated sludge, containing high levels of nutrients (1500 mg NH4(+)-N/L and 650 mg PO(3-)-P/L), organics (45.5 g COD/L) and suspended solids (3.5 g TSS/L), with reference to anaerobically digested sludge centrate. In a series of jar tests, the order of pH adjustment and chemical addition were first tested for the digested sludge centrate. The effects of MgCl2 and MgO, as Mg2+ sources, on SP were evaluated in both waste streams. Up to 80% of the dissolved PO4(3-)-P was recovered using MgO (pH = 9.2) from the pretreated sludge liquor and more than 86% of NH4(+)-N from the digested sludge centrate (pH = 8.0-8.5) regardless of the Mg2+ source used. NH4(+)-N recovery from digested sludge centrate required the addition of alkali, Mg2+ source and PO4(3-)-P, making the process less viable. The precipitates contained mostly struvite and some levels of Ca2+, Fe2+ and other Mg2+ phosphates. The levels of solids, inorganics and organics in the waste streams influenced SP, specifically struvite crystal formation and settleability in the pretreated sludge liquor, which suggests that the applicability of SP for nutrient recovery from complex waste streams requires case-by-case testing, and process optimization.

Biologically and chemically mediated adsorption and precipitation of phosphorus from wastewater.

Biologically and chemically mediated adsorption and precipitation processes offer a range of approaches for removing phosphorus (P) from agricultural, domestic and industrial effluents. Technologies implemented at full-scale include filtration by adsorbent media, such as steel slag, and recovery of phosphorus as struvite, which has been successfully commercialised as a fertiliser. Other promising technologies under investigation include P removal by polymers and nanomaterials as well as struvite formation by bacteria. There is a need to focus future research on improving the efficiency of P removal by adsorption and precipitation. This can be achieved by techniques such as regenerating filters, polymers and nanomaterials for renewed P removal. Research is also needed to optimise the fertiliser potential of struvite precipitates.

Separation and characterization of acetyl and non-acetyl hemicelluloses of Arundo donax by ammonium sulfate precipitation.

Delignified Arundo donax was sequentially extracted with DMSO, saturated barium hydroxide, and 1.0 M aqueous NaOH solution. The yields of the soluble fractions were 10.2, 6.7, and 10.0% (w/w), respectively, of the dry Arundo donax materials. The DMSO-, Ba(OH)(2)- and NaOH-soluble hemicellulosic fractions were further fractionated into two subfractions by gradient 50% and 80% saturation ammonium sulfate precipitation, respectively. Monosaccharide, molecular weight, FT-IR, and 1D ((1)H and (13)C) and 2D (HSQC) NMR analysis revealed the differences in structural characteristics and physicochemical properties among the subfractions. The subfractions precipitated with 50% saturation ammonium sulfate had lower arabinose/xylose and glucuronic acid/xylose ratios but had higher molecular weight than those of the subfractions precipitated by 80% saturation ammonium sulfate. FT-IR and NMR analysis revealed that the highly acetylated DMSO-soluble hemicellulosic subfraction (H(D50)) could be precipitated with a relatively lower concentration of 50% saturated ammonium sulfate, and thus the gradient ammonium sulfate precipitation technique could discriminate acetyl and non-acetyl hemicelluloses. It was found that the DMSO-soluble subfraction H(D50) precipitated by 50% saturated ammonium sulfate mainly consisted of poorly substituted O-acetyl arabino-4-O-methylglucurono xylan with terminal units of arabinose linked on position 3 of xylose, 4-O-methylglucuronic acid residues linked on position 2 of the xylan bone, and the acetyl groups (degree of acetylation, 37%) linked on position 2 or 3. The DMSO-soluble subfraction H(D80) precipitated by 80% saturated ammonium sulfate was mainly composed of highly substituted arabino-4-O-methylglucurono xylan and ß-d-glucan.

Proteomic characterization of specific minor proteins in the human milk casein fraction.

Human milk contains many bioactive proteins that are likely to support the early development of the newborn. The aim of this study was to identify whether there are specific minor proteins associated with the human milk casein micelle prepared by the acid precipitation method. Protein identification was performed by liquid chromatography tandem mass spectrometry analysis. Eighty-two proteins were identified in the casein micelle, 18 of which are not present in their whey compartment. Thirty-two of these proteins specifically associated with the casein micelle have not previously been identified in human milk or colostrum. Proteins involved in immune function comprised the major part (28%) of total proteins, and another significant part is involved in metabolism/energy production (22%). Most of the proteins were of extracellular or cytoplasmic origin (accounting for 50 and 29%, respectively). This study indicates that various soluble proteins should be considered as part of the casein compartment, prepared by the acid precipitation method. The data provide new insight not only into the proteomic profile of the human milk casein micelle and its physiological significance, but also into the proper proportion of casein and casein-associated proteins to use in infant formula.

Municipal wastewater phosphorus removal by coagulation.

This study investigated the chemical removal of phosphorus from wastewater by means of adsorption and precipitation. Using secondary effluent from municipal wastewater treatment plants as the model wastewater, phosphorus precipitation was tested with four commonly used metal salt coagulants, and phosphorus adsorption was explored by column experiments with goethite-coated silica sand as porous media. It was concluded that adsorption played a more important role than precipitation in phosphorus removal. As demonstrated by the column experiments (integration of the breakthrough curve), around 65% of phosphorus can be retained through adsorption by goethite-coated silica sand.

Direct isolation of high-quality low molecular weight RNA of pear peel from the extraction mixture containing nucleic acid.

Low molecular weight RNA (LMW RNA) is generally obtained either from the total RNA or from total nucleic acids solution. Many steps and chemical reagents are involved in traditional methods for LMW RNA isolation where degradation of LMW RNA often occurs, especially for plant materials with high levels of secondary catabolites. In this study, an efficient method was developed to directly isolate pure LMW RNA from pear peel, a material rich in polyphenolics that is covered with a layer of wax. The method was based on polyethylene glycol (PEG) precipitation combining CTAB buffer which is often used to isolate RNA from polysaccharide-rich and polyphenolics-rich materials. The entire procedure could be completed within 6 h and many samples could be processed at the same time. Few and common chemicals are used with this method. Hence, it could be used as an ordinary method in the laboratory. The developed method was further tested by isolating LMW RNA from Arabidopsis. Using the isolated LMW RNA samples, microRNAs were successfully detected and characterized.