A bioflocculant from Corynebacterium glutamicum and its application in acid mine wastewater treatment.

Although many microorganisms have been found to produce bioflocculants, and bioflocculants have been considered as attractive alternatives to chemical flocculants in wastewater treatment, there are few reports on bioflocculants from the safe strain C. glutamicum, and the application of bioflocculants in acid wastewater treatment is also rare attributed to the high content of metal ions and high acidity of the water. In this study, a novel bioflocculant produced by Corynebacterium glutamicum Cg1-P30 was investigated. An optimal production of this bioflocculant with a yield of 0.52 g/L was achieved by Box-Behnken design, using 12.20 g/L glucose, 4.00 g/L corn steep liquor and 3.60 g/L urea as carbon and nitrogen source. The structural characterization revealed that the bioflocculant was mainly composed of 37.50% neutral sugar, 10.03% uronic acid, 6.32% aminosugar and 16.51% protein. Carboxyl, amine and hydroxyl groups were the functional groups in flocculation. The biofocculant was thermally stable and dependent on metal ions and acidic pH, showing a good flocculating activity of 91.92% at the dosage of 25 mg/L by aid of 1.0 mM Fe3+ at pH 2.0. Due to these unique properties, the bioflocculant could efficiently remove metal ions such as Fe, Al, Zn, and Pb from the real acid mine wastewater sample without pH adjustment, and meanwhile made the acid mine wastewater solution become clear with an increased neutral pH. These findings suggested the great potential application of the non-toxic bioflocculant from C. glutamicum Cg1-P30 in acid mine wastewater treatment.

Effects of Nostoc sphaeroids Kütz polysaccharide on renal fibrosis in high-fat mice.

In this study, we investigated the effects of Nostoc sphaeroids Kütz polysaccharide (NSKP) on renal fibrosis in high-fat mice. ApoE-/- male mice were randomly divided into four groups: control (Cont) group, high-fat diet (HFD) group, HFD+0.4 g/kg BW NSKP, and HFD+0.8 g/kg BW NSKP (NSKP groups). The Cont was fed a standard diet. The HFD group was fed HFD. Every day, NSKP groups were fed HFD, as well as given 0.4 g/kg BW or 0.8 g/kg BW NSKP. After 22 weeks, the serum biochemical indices (TC, TG, LDL-C, HDL-C, GLU, BUN, and SCR) were measured. For the kidney, the histopathological sections were observed and analyzed, and inflammatory factors and markers of renal fibrosis were measured. For the NSKP groups, the serum TC, TG, LDL-C, BUN, and SCR were decreased, HDL-C significantly increased compared with the HFD group. The protein expressions of TNF-α, IL-1ß, and TGF-ß1 were significantly downregulated. The α-SMA in renal cortex was decreased, and the mRNA expression of Col-I and Col-IV in renal collagen fibers was downregulated. To sum up, NSKP reduced the blood lipid of HFD mice, downregulated the inflammation of kidney, inhibited the expression of collagen fiber, and improved the renal fibrosis caused by long-term lipid metabolism disorder.

Mutagenic and teratogenic toxicity evaluation of Forsythia suspensa leaves aqueous extract.

Forsythia suspensa leaves (FSL), rich in phillyrin, forsythiaside A, phillygenin, rutin, and other compounds, is a known traditional Chinese medicine (TCM). It has been effective in heat retreat and detoxification. In this study, we performed the mutagenic and teratogenic toxicity evaluation of FSL aqueous extract (FSLAE) using the bacterial reverse mutation assay (Ames test), mouse bone marrow micronucleus assay, spermatocyte chromosomal aberration assay in mice. Kunming mice and SD rats were used were for the mutagenic and the teratogenic studies, respectively. We found that FSLAE was not mutagenic and did not induce unfavorable chromosomal events. Additionally, the Ames test revealed FSLAE was not genotoxic and showed no mutagenic activity in histidine dependent strains of Salmonella typhimurium at concentrations up to 5000 µg/plate. Likewise, in vivo test revealed no induced micronucleus of mouse bone marrow or chromosome aberration in spermatocytes up to the dose of 10.00 g/kg BW. For the teratogenic evaluations, pregnant rats were treated with 1.04, 2.08, and 4.17 g/kg FSL, and fetuses were examined on the 6-15 day of pregnancy. We observed no maternal toxicity and embryotoxicity related to the treatment. Based on these in vitro and in vivo studies, we concluded the genotoxic and teratogenic safety of FSL.

Nostoc sphaeroides Kütz Polysaccharide Improved Constipation and Promoted Intestinal Motility in Rats.

Natural products and medicinal foods have attracted more and more attention because of their potential prevention and inhibition effect on constipation. Nostoc sphaeroides Kütz Polysaccharide (NSKP) polysaccharide is a natural product rich in polysaccharides. This work attempted to prove the effects of aqueous extracts of NSKP on STC treatment and to determine the possible mechanisms by a loperamide-induced slow transit constipation (STC) model. The results show that, in rats of the NSKP group, compared with the model group, the colon propulsion rate was improved, the time of the first grain of black stool was shortened, and the fecal wet weight was increased remarkably. The 5-HT levels were increased, but the VIP and NO levels were reduced dramatically. The number of interstitial cells of cajal (ICC) was increased by c-kit/SCF signal pathway, and the intestines were moisturized; then, constipation was relieved. It is interesting to note that NSKP appeared to be effective on constipation, so further experiments are necessary to clarify the exact mechanisms involved.

Nostoc sphaeroids Kütz ameliorates hyperlipidemia and maintains the intestinal barrier and gut microbiota composition of high-fat diet mice.

Hyperlipidemia is associated with chronic inflammation and intestinal dysbiosis. The purpose of this study was to investigate the protective effect of Nostoc sphaeroids Kütz (NO) on diet-induced hyperlipidemia in mice. Experimental animals received a high-fat diet (HFD) for 4 weeks, then an HFD supplemented with 2.5% or 7.5% NO for 6 weeks. HFD-fed mice exhibited a significant increase in serum total cholesterol, triglycerides, and low-density lipid cholesterol, and a decrease in high-density lipid cholesterol. NO supplementation was associated with significantly lower dyslipidemia, decreased intestinal inflammation, and inhibition of toll-like receptor 4 gene repression in HFD-fed mice. Results suggest that NO treatment protected the integrity of the intestinal barrier. NO treatment was also associated with significant changes in the intestinal microbiota induced by HFD and an increase in the Firmicutes-to-Bacteroidetes ratio. Furthermore, NO treatment was also inversely correlated with mice obesity and hyperlipidemia NO and was associated with no significant in fecal short-chain fatty acids. In conclusion, NO significantly ameliorated hyperlipidemia induced by a HFD in mice, potentially via a decrease intestinal inflammation, increase in intestinal barrier integrity, and amelioration in the gut microbiota.

Nostoc sphaeroids Kütz powder ameliorates diet-induced hyperlipidemia in C57BL/6j mice.

BACKGROUND: Hypercholesterolemia is a disease associated with numerous health problems. Growing evidence indicates that hypercholesterolemia, hyperlipidemia is closely linked to chronic inflammation, which can lead to cardiovascular disease, fatty liver disease, and type 2 diabetes. OBJECTIVE: The purpose of this study was to investigate the protective effect of Nostoc sphaeroids Kütz (NO) on diet-induced hyperlipidemia in mice. DESIGN: At first, experimental animals received a high-fat diet (HFD) for 4 weeks, and then received a HFD supplemented with 2.5% or 7.5% NO for 6 weeks. In the current study, results show that treatment with NO decreases weight gain and liver index induced by HFD. In addition, the serum levels of TC, TG and LDL are significantly decreased in NO treatment groups. RESULTS: From the results of Oil Red staining and Hematoxylin and eosin staining (HE), treatment with NO significantly reduces liver lipid accumulation and protect liver structure. Further analysis reveals that NO has positive effects on liver lipid metabolism and inflammation, as showed by the lower protein expressions of FAS and SREBP-1, the lower concentrations of TNF-α, IL-1ß, IL-6, and the lower gene expressions of TNF-α, IL-1ß, IL-6 and NF-kB. CONCLUSIONS: Our results indicate that NO may significantly ameliorate diet-induced hyperlipidemia, which is possibly associated with improving liver lipid metabolism and reducing chronic inflammation.