Fiber degradation potential of natural co-cultures of Neocallimastix frontalis and Methanobrevibacter ruminantium isolated from yaks (Bos grunniens) grazing on the Qinghai Tibetan Plateau.

Several natural anaerobic fungus-methanogen co-cultures have been isolated from rumen and feces source of herbivores with strong fiber degrading ability. In this study, we isolated 7 Neocallimastix with methanogen co-cultures from the rumen of yaks grazing on the Qinghai Tibetan Plateau. Based on morphological characteristics and internal transcribed spacer 1 sequences (ITS1), all the fungi were identified as Neocallimastix frontalis. The co-cultures were confirmed as the one fungus - one methanogen pattern by the PCR-denatured gradient gel electrophoresis (DGGE) assay. All the methanogens were identified as Methanobrevibacter ruminantium by 16s rRNA gene sequencing. We investigated the biodegrading capacity of the co-culture (N. frontalis + M. ruminantium) Yaktz1 on wheat straw, corn stalk and rice straw in a 7 days-incubation. The in vitro dry matter digestibility (IVDMD), acid detergent fiber digestibility (ADFD) and neural detergent fiber digestibility (NDFD) values of the substrates in the co-culture were significantly higher than those in the mono-culture N. frontalis Yaktz1. The co-culture exhibited high polysaccharide hydrolase (xylanase and FPase) and esterase activities. The xylanase in the co-culture reached the highest activity of 12500 mU/ml on wheat straw at the day 3 of the incubation. At the end of the incubation, 3.00 mmol-3.29 mmol/g dry matter of methane were produced by the co-culture. The co-culture also produced high level of acetate (40.00 mM-45.98 mM) as the end-product during the biodegradation. Interestingly, the N. frontalis Yaktz1 mono-culture produced large amount of lactate (8.27 mM-11.60 mM) and ethanol (163.11 mM-242.14 mM), many times more than those recorded in the previously reported anaerobic fungi. Our data suggests that the (N. frontalis + M. ruminantium) Yaktz1 co-culture and the N. frontalis Yaktz1 mono-culture both have great potentials for different industrial use.

Over-production of nitric oxide by oxidative stress-induced activation of the TGF-ß1/PI3K/Akt pathway in mesangial cells cultured in high glucose.

AIM: To investigate whether NO over-production in rat mesangial cells cultured in high glucose (HG) is related to activation of the TGF-ß1/PI3K/Akt pathway. METHODS: Rat mesangial cells line (HBZY-1) was exposed to HG (24.44 mmol/L) or H2O2 (10 µmol/L) for 16 h. NO release was quantified using the Griess assay. The TGF-ß1 level was measured using ELISA. The protein expression of p-Akt, t-Akt, Bim, and iNOS was examined by Western blotting. The mRNA levels of TGF-ß1 and Bim were measured using RT-PCR. The cell proliferation rate was estimated using a BrdU incorporation assay. RESULTS: Treatment of the cells with HG, H2O2, or TGF-ß1 (5 ng/mL) significantly increased the NO level that was substantially inhibited by co-treatment with the NADPH oxidase inhibitor diphenylene iodonium (DPI), TGF-ß1 inhibitor SB431542, or PI3K inhibitor LY294002. Both HG and H2O2 significantly increased the protein and mRNA levels of TGF-ß1 in the cells, and HG-induced increases of TGF-ß1 protein and mRNA were blocked by co-treatment with DPI. Furthermore, the treatment with HG or H2O2 significantly increased the expression of phosphorylated Akt and iNOS and cell proliferation rate, which was blocked by co-treatment with DPI, SB431542, or LY294002. Moreover, the treatment with HG or H2O2 significantly inhibited Bim protein and mRNA expression, which was reversed by co-treatment with DPI, SB431542, or LY294002. CONCLUSION: The results demonstrate that high glucose causes oxidative stress and NO over-production in rat mesangial cells in vitro via decreasing Bim and increasing iNOS, which are at least partially mediated by the TGF-ß1/PI3K/Akt pathway.

Development of magnetic molecularly imprinted polymers with double templates for the rapid and selective determination of carbamazepine and lamotrigine in serum.

A dual-template magnetic molecularly imprinted polymer (Dt-MMIP) with a specific recognition capability for carbamazepine (CBZ) and lamotrigine (LTG) was synthesized using methacrylic acid as a functional monomer, and ethylene glycol dimethylmethacrylate as a cross-linking agent. A magnetic non-molecularly imprinted polymer without templates (MNIP) was also prepared using the same procedure. The prepared polymers were characterized using scanning electron microscopy, Fourier-transform infrared spectroscopy and adsorption experiments. Results indicated that both Dt-MMIPs and MNIPs were microspherical nanoparticles, and the surface of the Dt-MMIP was rougher than that of the MNIP. In addition, the prepared Dt-MMIPs possessed a higher adsorption capacity and better selectivity for CBZ and LTG than the MNIPs. The maximum static adsorption capacities of Dt-MMIP for CBZ and LTG were 249.5 and 647.9 µg g-1, respectively, whereas those of MNIP were 75.8 and 379.8 µg g-1, respectively. The obtained Dt-MMIPs were applied as a magnetic solid-phase extraction sorbent for the rapid and selective extraction of CBZ and LTG in rat serum samples, and determination was performed by high-performance liquid chromatography with UV detection (HPLC-UV). The developed method of dispersive SPE based on Dt-MMIPs coupled to HPLC-UV has good rapidity and selectivity, and application prospects in serum.

Protective effects of rutin on rat glomerular mesangial cells cultured in high glucose conditions.

The protective effect of rutin on the glomerulosclerosis of diabetic nephropathy (DN) in rat mesangial cells was investigated. The cultured mesangial cells were divided into eight groups: normal, solvent control, high glucose, low dose of rutin, moderate dose of rutin, high dose of rutin, captopril and Ginkgo biloba extract. The cell cycles, type IV collagen and laminin in cytoplasm, TGF-ß1 mRNA of mesangial cells, Smad 2/3 and Smad 7, and the activities of four antioxidant indexes including T-SOD, MDA, CAT and GSH-Px were measured by flow cytometry, radioimmunoassay, RT-PCR, western blotting and visible spectrophotometry, respectively. Compared with the high glucose group, rutin decreased the cell percentages of the G0/G1 phase and inhibited the expression of Smad 2/3, laminin and type IV collagen, and TGF-ß1 mRNA level, significantly. The antioxidant capacity, the cell percentages of S phase and Smad 7 expression were significantly increased by rutin. These results suggest that rutin is a potent protective agent against glomerulosclerosis in DN.

Characterization of natural co-cultures of Piromyces with Methanobrevibacter ruminantium from yaks grazing on the Qinghai-Tibetan Plateau: a microbial consortium with high potential in plant biomass degradation.

Anaerobic fungi reside in the gut of herbivore and synergize with associated methanogenic archaea to decompose ingested plant biomass. Despite their potential for use in bioconversion industry, only a few natural fungus-methanogen co-cultures have been isolated and characterized. In this study we identified three co-cultures of Piromyces with Methanobrevibacter ruminantium from the rumen of yaks grazing on the Qinghai Tibetan Plateau. The representative co-culture, namely (Piromyces + M. ruminantium) Yak-G18, showed remarkable polysaccharide hydrolase production, especially xylanase. Consequently, it was able to degrade various lignocellulose substrates with a biodegrading capability superior to most previously identified fungus or fungus-methanogen co-culture isolates. End-product profiling analysis validated the beneficial metabolic impact of associated methanogen on fungus as revealed by high-yield production of methane and acetate and sustained growth on lignocellulose. Together, our data demonstrated a great potential of (Piromyces + M. ruminantium) Yak-G18 co-culture for use in industrial bioconversion of lignocellulosic biomass.

Suppression of methylglyoxal hyperactivity by mangiferin can prevent diabetes-associated cognitive decline in rats.

RATIONALE: Evidences indicate that methylglyoxal, a highly reactive metabolite of hyperglycemia, can enhance protein glycation, oxidative stress, or inflammation. Mangiferin, a polyphenol compound of C-glucoside, has many beneficial biological activities, including anti-inflammation, anti-oxidation, neuroprotection, cognitive enhancement, etc. Whether mangiferin alleviates diabetes-associated cognitive impairment is still unclear. OBJECTIVES: The present study was designed to investigate the effects of mangiferin on the behavioral deficits of diabetic rats induced by streptozotocin; the mechanisms associated with methylglyoxal toxicity are especially investigated. METHODS: Diabetic rats were treated with mangiferin (15, 30, and 60 mg/kg, p.o.) for 9 weeks. Cognitive performances were evaluated with the Morris water maze. Hippocampus and blood were obtained for evaluation of the effects of mangiferin on protein glycation, oxidative stress, and inflammation in diabetic state. RESULTS: Mangiferin significantly improved the behavioral performances of diabetic rats, evidenced by a decrease in escape latency as well as increases in numbers of crossing the platform and percentage of time spent in the target quadrant, which were accompanied by decreases in the levels of advanced glycation end-products and their receptor (RAGE), interleukin-1ß, TNF-α, and malondialdehyde and increases in the activity and expression of glyoxalase 1 as well as glutathione level in the hippocampus of diabetic rats. Furthermore, mangiferin produced a significant decrease in malondialdehyde level and increased glutathione level and superoxide dismutase activity in the serum of diabetic rats. CONCLUSIONS: This study demonstrates that mangiferin can markedly ameliorate diabetes-associated cognitive decline in rats, which is done likely through suppressing methylglyoxal hyperactivity (promoting protein glycation, oxidative stress, and inflammation) mediated noxious effects.

Total saponins from Rhizoma Anemarrhenae ameliorate diabetes-associated cognitive decline in rats: involvement of amyloid-beta decrease in brain.

ETHNOPHARMACOLOGICAL RELEVANCE: As a well-known Chinese Materia Medica Rhizoma Anemarrhenae has multiple pharmacological activities including antipyretic, anti-inflammatory, anti-diabetic actions, etc. This study was designed to investigate effects of total saponins from Rhizoma Anemarrhenae (TS) on diabetes-associated cognitive decline in rats and influence on amyloid-beta (Aß) levels in brain and inflammation. MATERIALS AND METHODS: Diabetic rats induced by intraperitoneal administration of streptozotocin, were randomized into two groups: diabetes and TS-treated diabetes. Blood glucose and body weight were measured monthly and weekly, respectively. After seven weeks, cognitive performances were evaluated with Morris water maze. Then, brain was obtained for assay of Aß and TNF-α levels, and blood was collected for TNF-α assay. RESULTS: Aß(1-40), Aß(1-42) and TNF-α levels were dramatically (all P<0.01) increased both in temporal cortex and hippocampus of diabetic rats, coupled with impairment of cognition, compared with those of the control. Chronic TS (200mg/kg) treatment markedly (P<0.05) improved the learning ability of diabetic rats, and significantly (all P<0.05) reduced Aß(1-40), Aß(1-42) and TNF-α levels in cortex as well as Aß(1-40) level in hippocampus, whereas showed a decreased tendency for Aß(1-42) and TNF-α levels in hippocampus. Moreover, eight-week treatment with TS remarkably (P<0.05) inhibited the elevation of TNF-α level in serum of diabetic rats, and significantly (both P<0.01) decrease the fasting blood glucose level and increase the body weight of diabectic rats. CONCLUSION: Our findings demonstrate that diabetes-associated cognitive decline is, at least in part, due to brain Aß accumulation in diabetic condition, and efficacy of TS to diabetes-associated cognitive decline in rats is a sum of reduction of Aß accumulation and inflammation in brain as well as attenuation of major symptoms of diabetes.

Ginsenoside Re attenuates diabetes-associated cognitive deficits in rats.

OBJECTIVE: This study was designed to investigate the effect of ginsenoside Re (Re) on cognitive functions, oxidative stress and inflammation in streptozotocin-induced diabetic rats. RESEARCH DESIGN AND METHOD: Diabetic rats were treated with Re (40mg/kg) for 8weeks, blood glucose and body weight were measured monthly and weekly, respectively. Cognitive performances were evaluated with Morris water maze. Brain was obtained for measurements of TNF-α and malondialdehyde (MDA) contents in both temporal cortex and hippocampus, blood was collected for assays of TNF-α, MDA and reduced glutathione (GSH) levels. RESULTS: Learning and memory abilities were significantly (both P<0.01) impaired in diabetic rats, accompanied by the marked (all P<0.01) elevations of TNF-α and MDA levels in temporal cortex and hippocampus. Increment of MDA and decrement of GSH in serum also occurred with significant differences (both P<0.01). Chronic treatment with Re markedly (P<0.05) improved the cognition of diabetic rats, evidenced by the decreased escape latency and the increased percentage of time spent in the target quadrant. Furthermore, Re treatment remarkably (P<0.05) reduced the levels of TNF-α and MDA in both brain areas of diabetic rats. Decline of MDA level and elevation of GSH level in serum were also seen in Re-treated diabetic rats, coupled with decrease in serum glucose level, all with statistically significant differences. CONCLUSIONS: Our findings firstly provide the first evidence that ginsenoside Re can remarkably attenuate diabetes-associated cognitive decline, secondly confirm the involvement of oxidative stress and inflammation in the development of cognitive impairment caused by diabetes, finally point toward the potential of ginsenoside Re as an adjuvant therapy to conventional anti-hyperglycemic regimens as well as diabetes-associated cognitive decline.

In vitro suppression of quercetin on hypertrophy and extracellular matrix accumulation in rat glomerular mesangial cells cultured by high glucose.

Quercetin's protective effects on the glomerulosclerosis of diabetic nephropathy (DN) in rat mesangial cells were investigated. The cell cycles, type IV collagen and laminin, TGF-ß(1) mRNA, Smad 2/3 and Smad 7, and activities of cell antioxidases were measured. Compared with the high glucose group, quercetin may decrease the cell percentages of G(0)/G(1) phase, Smad 2/3 expression, laminin and type IV collagen, and TGF-ß(1) mRNA level significantly. The antioxidant capacity, the cell percentages of S phase and Smad 7 expression was significantly increased by quercetin. These results suggest that quercetin is a protective agent against glomerulosclerosis in DN.