Purification and characterization of Cu,Zn superoxide dismutase from pumpkin (Cucurbita moschata) pulp

Characterization, the Antioxidant and Antimicrobial Activity of Exopolysaccharide Isolated from Poultry Origin Lactobacilli

The natural antioxidant agent is urgently needed to prevent the negative effects of newly generated free radicals and chronic disorders. Recently, the microbial exopolysaccharide (EPS) is currently used as a potential biopolymer due to its unique biological characteristics. In this study, the biological potential was carried out on the EPSs produced by Lactobacillus reuteri SHA101 (EPS-lr) and Lactobacillus vaginalis SHA110 (EPS-lvg) isolated from gut cecum samples of healthy poultry birds (hen). As results, the EPS-lr and EPS-lvg showed the emulsifying activity of 37.8 ± 1.6% and 27.8 ± 0.5% after the 360 h, respectively. The scanning electron microscopy analysis of EPS-lr and EPS-lvg demonstrated a smooth surface with a compact structure. The both EPSs exhibited strong antibacterial activity against E. coli and Salmonella typhimurium in vitro. In additions, at 4 mg/mL concentration, the EPS-lr and EPS-lvg samples showed potent antioxidant activity regarding hydroxyl radical DPPH (2,2-diphenyl-1-picrylhydrazyl) radical, superoxide anion radical and reducing power at OD_700 nm. Furthermore, the EPS-lr and EPS-lvg (600 μg/mL) possessed antitumor activity against colon cancer (Caco-2) cell after 72 h. The results suggested that these EPSs would have great potential in the application of antitumor and antioxidant foods, biomedicine, and pharmaceutics.

Structural characterization and antioxidant potential of a novel exopolysaccharide produced by Bacillus velezensis SN-1 from spontaneously fermented Da-Jiang

The aim of this study was to characterize the exopolysaccharide (EPS) produced by Bacillus velezensis SN-1 (B. velezensis SN-1) (EPS-SN-1), which was isolated from the fermented Da jiang. The microbe made crude exopolysaccharides EPS-SN-1 was produced throughout the bacterial growth period, and the highest yield (2.7 g/L) was obtained with sucrose as the carbon source. As per high performance liquid chromatography (HPLC), EPS-SN-1 is a heteropolysaccharide consisting of glucose, mannose and fructose, with a high molecular weight of 2.21 × 10⁵ Da. FTIR spectra further indicated the presence of hydroxyl and carbonyl groups, and NMR analysis confirmed both α- and β-glycosidic bonds. Furthermore, differential scanning calorimetry (DSC) showed that EPS-SN-1 has high thermal stability with fusion point of 270.7 °C. Finally, EPS-SN-1 demonstrated strong antioxidant capacity via its ability to scavenge hydroxyl radical (^•OH), 1,1-diphenyl-2-picrylhydrazyl (DPPH^•) radical, ABTS radical (ABTS^•+) and oxygen radical (O₂^-•). Taken together, EPS-SN-1 is a promising natural antioxidant and probiotic with potential applications in the food industry.

The anti-tumor activity of exopolysaccharides from Pseudomonas strains against HT-29 colorectal cancer cell line

The anti-tumor activity of extracted exopolysaccharides (EPSs) (without any side effects) of Pseudomonas aeruginosa on HT-29 colorectal cancer cell line has not been previously investigated. The extraction and partial characterization of EPS from the strains of P. aeruginosa including A (CIP A22(PTCC1310)), and B (a clinical strain) were performed. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and sulphorhodamine B (SRB) assays as well as microscopy were used to estimate the cell viability and morphological changes in HT-29 cells subjected to EPS at 0, 7.6, 15.8, 31.2, 62.5 and 125 μg/ml. The apoptotic effects of EPS were also examined by flow cytometry. The EPSs were found to be cytotoxic against HT-29 cells with IC50 values at 44.8 (EPS-A) and 12.7 (EPS-B) μg/ml. The counteraction of 125 μg/ml of EPS-A (87.5 and 56.7%) and EPS-B (86.7 and 59.2%) resulted in the highest repressive rates using the MTT and SRB assays, respectively. Flow cytometric results showed that EPS-A and EPS-B could induce apoptosis (33% and 39%) and necrosis (65% and 59%). The extracted EPSs of both bacterial strains can be used as natural, effective, efficient and anti-cancer drugs. However, more characterization at molecular and structural levels in this respect may be required.

Cloning, expression and biochemical characterization of recombinant superoxide dismutase from Antarctic psychrophilic bacterium Pseudoalteromonas sp. ANT506

In this study, a superoxide dismutase gene (PsSOD) from Pseudoalteromonas sp. ANT506 was cloned and over expressed in Escherichia coli. The PsSOD has an open reading frame of 582 bp with a putative product of 193 amino acid residue and an estimated molecular size of 21.4 kDa. His-tagged PsSOD was subsequently purified 12.6-fold by Ni-affinity chromatography and the yield of 22.9%. The characterization of the purified rPsSOD exhibited maximum activity at 30 °C and pH 8.0. The enzyme exhibited 13.9% activity at 0 °C and had high-thermo lability at higher than 50 °C. rPsSOD exhibited well capability to 2.5 M NaCl (62.4%). These results indicated that rPsSOD exhibited special catalytic properties.