D-mannose has many functional activities and is widely used in food, medicine, agriculture and other industries. D-mannitol oxidase that can efficiently convert D-mannitol into D-mannose has potential application in the enzymatic preparation of D-mannose. A D-mannitol oxidase (PsOX) was found from Paenibacillus sp. HGF5. The similarity between PsOX and the D-mannitol oxidase (AldO) from Streptomyces coelicolor was 50.94%. The molecular weight of PsOX was about 47.4 kDa. A recombinant expression plasmid pET-28a-PsOX was constructed and expressed in Escherichia coli BL21(DE3). The K_m and k_cat/K_m values of PsOX for D-mannitol were 5.6 mmol/L and 0.68 L/(s·mmol). Further characterization of PsOX showed its optimal pH and temperature were 7.0 and 35 ℃, respectively, while its enzyme activity could be stably remained below 60 ℃. The molar conversion rate of 400 mmol/L D-mannitol by PsOX was 95.2%. The whole cells of PsOX and AldO were used to catalyze 73 g/L D-mannitol respectively. The reaction catalyzed by PsOX completed in 9 h and 70 g/L D-mannose was produced. PsOX showed a higher catalytic efficiency compared to that of AldO. PsOX may facilitate the enzymatic preparation of D-mannose as a novel D-mannose oxidase.
Recombinant Proteins/metabolism* ; Paenibacillus/metabolism* ; Mannose/metabolism* ; Escherichia coli/metabolism* ; Mannitol/metabolism*

OBJECTIVE: To explore the protective effect and underlying mechanism of Lycium barbarum polysaccharides (LBP) in a non-alcoholic fatty liver disease (NAFLD) cell model. METHODS: Normal human hepatocyte LO2 cells were treated with 1 mmol/L free fatty acids (FFA) mixture for 24 h to induce NAFLD cell model. Cells were divided into 5 groups, including control, model, low-, medium- and high dose LBP (30,100 and 300 µg/mL) groups. The monosaccharide components of LBP were analyzed with high performance liquid chromatography. Effects of LBP on cell viability and intracellular lipid accumulation were assessed by cell counting Kit-8 assay and oil red O staining, respectively. Triglyceride (TG), alanine aminotransferase (ALT), aspartate aminotransferase (AST), adenosine triphosphate (ATP) and oxidative stress indicators were evaluated. Energy balance and mitochondrial biogenesis related mRNA and proteins were determined by quantitative real-time polymerase chain reaction and Western blot, respectively. RESULTS: Heteropolysaccharides with mannose and glucose are the main components of LBP. LBP treatment significantly decreased intracellular lipid accumulation as well as TG, ALT, AST and malondialdehyde levels (P<0.05 or P<0.01), increased the levels of superoxide dismutase, phospholipid hydroperoxide glutathione peroxidase, catalase, and ATP in NAFLD cell model (P<0.05). Meanwhile, the expression of uncoupling protein 2 was down-regulated and peroxisome proliferator-activated receptor gamma coactivator-1α/nuclear respiratory factor 1/mitochondrial transcription factor A pathway was up-regulated (P<0.05). CONCLUSION LBP promotes mitochondrial biogenesis and improves energy balance in NAFLD cell model.
Humans ; Non-alcoholic Fatty Liver Disease/drug therapy* ; Lycium/metabolism* ; Catalase/metabolism* ; Organelle Biogenesis ; Alanine Transaminase ; Uncoupling Protein 2 ; Fatty Acids, Nonesterified ; Mannose ; Nuclear Respiratory Factor 1/metabolism* ; PPAR gamma/metabolism* ; Phospholipid Hydroperoxide Glutathione Peroxidase ; Drugs, Chinese Herbal/pharmacology* ; Malondialdehyde/metabolism* ; Superoxide Dismutase/metabolism* ; Polysaccharides/pharmacology* ; Triglycerides ; RNA, Messenger ; Aspartate Aminotransferases ; Glucose ; Adenosine Triphosphate

We have previously reported that NS-398, a cyclooxygenase-2 (COX-2)–selective inhibitor, inhibited replicative cellular senescence in human dermal fibroblasts and skin aging in hairless mice. In contrast, celecoxib, another COX-2–selective inhibitor, and aspirin, a non-selective COX inhibitor, accelerated the senescence and aging. To figure out causal factors for the senescence-modulating effect of the inhibitors, we here performed cDNA microarray experiment and subsequent Gene Set Enrichment Analysis. The data showed that several senescence-related gene sets were regulated by the inhibitor treatment. NS-398 up-regulated gene sets involved in the tumor necrosis factor β receptor pathway and the fructose and mannose metabolism, whereas it down-regulated a gene set involved in protein secretion. Celecoxib up-regulated gene sets involved in G2M checkpoint and E2F targets. Aspirin up-regulated the gene set involved in protein secretion, and down-regulated gene sets involved in RNA transcription. These results suggest that COX inhibitors modulate cellular senescence by different mechanisms and will provide useful information to understand senescence-modulating mechanisms of COX inhibitors.
Aging ; Animals ; Aspirin ; Celecoxib ; Cell Aging ; Cyclooxygenase 2 ; Fibroblasts* ; Fructose ; Gene Expression* ; Genes, vif ; Humans* ; Mannose ; Metabolism ; Mice ; Mice, Hairless ; Oligonucleotide Array Sequence Analysis ; RNA ; Skin Aging ; Tumor Necrosis Factor-alpha

OBJECTIVETo investigate the effect of low-selenium diet on the liver and kidneys of rats and explore the role of macrophage polarization into M1 and M2 phenotypes in liver and kidney injuries.

METHODSTwenty-four rats (12 female and 12 male) were randomly divided into control group and low-selenium group and fed with normal chow (dietary selenium of 0.18 mg/kg) and low-selenium diet (dietary selenium of 0.02 mg/kg) for 109 days. After the feeding, the rats were sacrificed for HE staining to observe liver and kidney pathologies, and immunohistochemistry was performed for analyzing CCR7, CD206, CD163-positive cell numbers in the liver and kidneys.

RESULTSThe rats in low-selenium group showed severer fibrosis in the liver and kidney than the control group. In either male or female rats in low-selenium group, CCR7 and CD206 expressions in the liver were comparable with those in control group, but CD163 expression was lower than that in the control group (P<0.05 for both female and male rats). In the kidney, the proximal tubule showed a slightly higher while the distal tubule showed a slightly lower CCR7 expression in low selenium group than in the control group (P>0.05). In low-selenium group, a significantly lower CD163 expression in the distal tubule and a significantly higher CD206 expression in the proximal tubule were noted as compared with the control group (P<0.05 in both female and male rats). Compared with the control rats, the male rats in low-selenium group, but not the female rats, showed a significantly lower CD163 expression in the proximal tubule of the kidney (P<0.05); the female but not the male rats in low-selenium group show a higher CD206 expression in the distal tubule (P<0.05).

CONCLUSIONLow-selenium diet can cause liver and kidney fibrosis in rats and may inhibit macrophage activation into the M2 phenotype.

Animals ; Antigens, CD ; metabolism ; Antigens, Differentiation, Myelomonocytic ; metabolism ; Diet ; Female ; Fibrosis ; Kidney ; metabolism ; pathology ; Lectins, C-Type ; metabolism ; Liver ; metabolism ; pathology ; Macrophage Activation ; Male ; Mannose-Binding Lectins ; metabolism ; Rats ; Receptors, CCR7 ; metabolism ; Receptors, Cell Surface ; metabolism ; Selenium ; administration & dosage

Polymeric micelles have exhibited attractive properties as drug carriers, such as high stability in vivo and good biocompatibility, and been successfully used to dissolve various drugs of poor aqueous solubilities. In this study, we developed a new type of polymeric micelles with mannose-mediated targeting and pH-responsive drug release properties for anticancer drug delivery. The polymeric micelles were prepared from an amphiphilic polymer, poly (glycidyl methacrylate)-g-mannose (PGMA-Mannose). An anticancer drug, doxorubicin (DOX), was encapsulated into the micelles during the micellization, and could be released rapidly under acidic condition. The specificity of cellular uptake of the micelles by two different cell lines was studied using confocal laser scanning microscopy and the MTT assay. DOX-loaded micelles were efficiently trapped by mannose-receptor-overexpressing cancer cells MDA-MB-231, whereas mannose- receptor-poor cells HEK293 showed much lower endocytosis towards the micelles under the same conditions. Thus, DOX-loaded micelles displayed higher cytotoxicity to MDA-MB-231 cancer cells as compared with free DOX. The present study demonstrates that PGMA-Mannose micelles are a promising targeted drug delivery system for cancer therapy.
Cell Line, Tumor ; Doxorubicin ; pharmacology ; Drug Delivery Systems ; HEK293 Cells ; Humans ; Lectins, C-Type ; metabolism ; Mannose ; chemistry ; Mannose-Binding Lectins ; metabolism ; Micelles ; Receptors, Cell Surface ; metabolism

BACKGROUND/AIMS: This animal study aimed to define the underlying cellular mechanisms of intestinal barrier dysfunction. METHODS: Rats were fed 4% with dextran sodium sulfate (DSS) to induce experimental colitis. We analyzed the sugars in 24-hour urine output by high pressure liquid chromatography. The expression of claudins, mannan-binding lectin (MBL), and MBL-associated serine proteases 2 (MASP-2) were detected in the colonic mucosa by immunohistochemistry; and apoptotic cells in the colonic epithelium were detected by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling method assay. RESULTS: The lactulose and sucralose excretion levels in the urine of rats with DSS-induced colitis were significantly higher than those in the control rats. Mannitol excretion was lower and lactulose/mannitol ratios and sucralose/mannitol ratios were significantly increased compared with those in the control group (p<0.05). Compared with the controls, the expression of sealing claudins (claudin 3, claudin 5, and claudin 8) was significantly decreased, but that of claudin 1 was increased. The expression of pore-forming claudin 2 was upregulated and claudin 7 was downregulated in DSS-induced colitis. The epithelial apoptotic ratio was 2.8%+/-1.2% in controls and was significantly increased to 7.2%+/-1.2% in DSS-induced colitis. The expression of MBL and MASP-2 in the intestinal mucosa showed intense staining in controls, whereas there was weak staining in the rats with colitis. CONCLUSIONS: There was increased intestinal permeability in DSS-induced colitis. Changes in the expression and distribution of claudins, increased epithelial apoptosis, and the MASP-2-induced immune response impaired the intestinal epithelium and contributed to high intestinal permeability.
Animals ; Apoptosis/*physiology ; Claudins/*metabolism ; Colitis/chemically induced/immunology/*physiopathology ; Colon/immunology/physiopathology ; Dextran Sulfate ; Intestinal Mucosa/*physiopathology ; Lactulose/metabolism ; Mannitol/metabolism ; Mannose-Binding Lectin/*immunology ; Permeability ; Rats ; Rats, Sprague-Dawley ; Sucrose/analogs & derivatives/metabolism ; Up-Regulation

No abstract available.
Animals ; Apoptosis/*physiology ; Claudins/*metabolism ; Colitis/*physiopathology ; Intestinal Mucosa/*physiopathology ; Mannose-Binding Lectin/*immunology

In order to determine the suitable harvest time of Dendrobium officinale from different regions in Yunnan province, the drying rate, mannose and glucose peak area ratio, extract, contents of polysaccharide and mannose of D. officinale samples collected from six producing areas in Ynnnan province were determined. The results indicate that drying rate and the contents of polysaccharide and mannose arrived the peak from January to April, extract reached a higher content from September to December, and mannose and glucose peak area ratio from October to February of the coming met the requirment of the Chinese Pharmacopoeia. Hence, the suitable harvesting time of D. officinale in Yunnan province is from December to February of the coming year,according to the experimental results and the request of the Chinese Pharmacopoeia.
China ; Dendrobium ; chemistry ; growth & development ; metabolism ; Glucose ; analysis ; metabolism ; Mannose ; analysis ; metabolism ; Time Factors

Flocculent gene FLO1 and its truncated form FLO1c with complete deletion of repeat unit C were expressed in a non-flocculent industrial strain Saccharomyces cerevisiae CE6 to generate recombinant flocculent strains 6-AF1 and 6-AF1c respectively. Both strains of 6-AF1 and 6-AF1c displayed strong flocculation and better cell growth than the control strain CE6-V carrying the empty vector under acetic acid stress. Moreover, the flocculent strains converted glucose to ethanol at much higher rates than the control strain CE6-V under acetic acid stress. In the presence of 0.6% (V/V) acetic acid, the average ethanol production rates of 6-AF1 and 6-AF1c were 1.56 and 1.62 times of that of strain CE6-V, while the ethanol production rates of 6-AF1 and 6-AF1c were 1.21 and 1.78 times of that of strain CE6-V under 1.0% acetic acid stress. Results in this study indicate that acetic acid tolerance and fermentation performance of industrial S. cerevisiae under acetic acid stress can be improved largely by flocculation endowed by expression of flocculent genes, especially FLO1c.
Acetic Acid ; chemistry ; Ethanol ; Fermentation ; Flocculation ; Glucose ; Industrial Microbiology ; Mannose-Binding Lectins ; genetics ; Saccharomyces cerevisiae ; genetics ; metabolism ; Saccharomyces cerevisiae Proteins ; genetics

OBJECTIVETo explore the significance of plasma levels of mannan-binding lectin (MBL)-associated serine protease 2 (MASP2) in children with upper respiratory tract infection (URTI).

METHODSA total of 103 children with URTI and 35 healthy children were examined for plasma levels of MASP2 and C-reactive protein (CRP). According to CRP levels, white blood cell count (WBC), stage of infection, and administration of treatments, the children with URTI were divided into the elevated CRP group (n=48) and the normal CRP group (n=54), elevated WBC group (n=61) and normal WBC group (n=40), the early stage of infection without treatment group (n=68) and mid-late stage of infection with treatment group (n=35).

RESULTSPlasma MASP2 levels was significantly higher in URTI group than in the healthy control group (P<0.001) and showed a close correlation with age (r=0.302, P<0.01). Plasma MASP2 level was significantly correlated with CRP level in elevated CRP group (r=0.310, P<0.05) but not in normal CRP group (P>0.05), correlated with WBC in elevated WBC group (r=0.392, P<0.01) but not in normal WBC group (P>0.05), and was significantly higher in early stage infection without treatment group than in mid-late stage of infection with treatment group (P<0.01). MASP2, MBL2 and CRP genes had a common binding site for the transcription factor HNF-4α.

CONCLUSIONSMASP2 may be an acute-phase protein, and its plasma level might serve as a new reference index in the diagnosis of URTI in children.

C-Reactive Protein ; metabolism ; Case-Control Studies ; Child ; Humans ; Leukocyte Count ; Mannose-Binding Protein-Associated Serine Proteases ; metabolism ; Respiratory Tract Infections ; blood