Synergistic effects of magnesium ions and simvastatin on attenuation of high-fat diet-induced bone loss

Introduction:Magnesium(Mg)has a prophylactic potential against the onset of hyperlipidemia.Similar to statin,Mg is recommended as lipid-lowering medication for hypercholesterolemia and concomitantly exhibits an association with increased bone mass.The combination of statin with Mg ions(Mg^(2+))may be able to alleviate the high-fat diet(HFD)-induced bone loss and reduce the side-effects of statin.This study aimed to explore the feasibility of combined Mg^(2+)with simvastatin(SIM)for treating HFD-induced bone loss in mice and the involving mechanisms.Materials and methods:C57BL/6 male mice were fed with a HFD or a normal-fat diet(NFD).Mice were intraperitoneally injected SIM and/or orally received water with additional Mg^(2+)until sacrificed.Enzyme-linked immunosorbent assay was performed to measure cytokines and cholesterol in serum and liver lysates.Bone mineral density(BMD)and microarchitecture were assessed by micro-computed tomography(μCT)in different groups.The adipogenesis in palmitate pre-treated HepG2 cells was performed under various treatments.Results:μCT analysis showed that the trabecular bone mass was significantly lower in the HFD-fed group than that in NFD-fed group since week 8.The cortical thickness in HFD-fed group had a significant decrease at week 24,as compared with NFD-fed group.The combination of Mg^(2+)and SIM significantly attenuated the trabecular bone loss in HFD-fed mice via arresting the osteoclast formation and bone resorption.Besides,such combination also reduced the hepatocytic synthesis of cholesterol and inhibited matrix metallopeptidase 13(Mmp13)mRNA expression in pre-osteoclasts.Conclusions:The combination of Mg^(2+)and SIM shows a synergistic effect on attenuating the HFD-induced bone loss.Our current formulation may be a cost-effective alternative treatment to be indicated for obesity-related bone loss.

Anaerobic digestion of sludge by different pretreatments:Changes of amino acids and microbial community

Many studies have investigated the effects of different pretreatments on the performance of anaerobic digestion of sludge.However,the detailed changes of dissolved organic nitrogen,particularly the release behavior of proteins and the byproducts of protein hydrolysis-amino acids,are rarely known during anaerobic digestion of sludge by different pretreatments.Here we quantified the changes of three types of proteins and 17 types of amino acids in sludge samples solubilized by ultrasonic,thermal,and acid/alkaline pretreatments and their transformation during anaerobic digestion of sludge.Tryptophan protein,aromatic protein I,aromatic protein II,and cysteine were identified as the key dissolved organic nitrogen responsible for methane production during anaerobic digestion of sludge,regardless of the different pretreatment methods.Different from the depletion of other amino acids,cysteine was resistant to degradation after an incubation period of 30 days in all sludge samples.Meanwhile,the“cysteine and methionine metabolism(K00270)”was absent in all sludge samples by identifying 6755 Kyoto Encyclopedia of Genes and Genomes assignments of genes hits.Cysteine contributed to the generation of methane and the degradation of acetic,propionic,and n-butyric acids through decreasing oxidation-reduction potential and enhancing biomass activity.This study provided an alternative strategy to enhance anaerobic digestion of sludge through in situ production of cysteine.

Comparison of different valent iron on anaerobic sludge digestion:Focusing on oxidation reduction potential,dissolved organic nitrogen and microbial community

This study compared effects of three different valent iron(Fe^(0),Fe(II)and Fe(III))on enhanced anaerobic sludge digestion,focusing on the changes of oxidation reduction potential(ORP),dissolved organic nitrogen(DON),and microbial community.Under the same iron dose in range of 0−160 mg/L after an incubation period of 30 days(d),the maximum methane production rate of sludge samples dosed with respective Fe^(0),Fe(II)and Fe(III)at the same concentration showed indiscernible differences at each iron dose,regardless of the different iron valence.Moreover,their behavior in changes of ORP,DON and microbial community was different:(1)the addition of Fe^(0) made the ORP of sludge more negative,and the addition of Fe(II)and Fe(III)made the ORP of sludge less negative.However,whether being more or less negative,the changes of ORP may show unobservable effects on methane yield when it ranged from−278.71 to−379.80 mV;(2)the degradation of dissolved organic nitrogen,particularly proteins,was less efficient in sludge samples dosed with Fe^(0) compared with those dosed with Fe(II)and Fe(III)after an incubation period of 30 d.At the same dose of 160 mg/L iron,more cysteine was noted in sludge samples dosed with Fe(II)(30.74 mg/L)and Fe(III)(27.92 mg/L)compared with that dosed with Fe^(0)(21.75 mg/L);(3)Fe^(0) particularly promoted the enrichment of Geobacter,and it was 6 times higher than those in sludge samples dosed with Fe(II)and Fe(III)at the same dose of 160 mg/L iron.