Foodborne toxin Aflatoxin B_(1)induced glomerular podocyte inflammation through proteolysis of RelA,downregulation of miR-9 and CXCR4/TXNIP/NLRP3 pathway

Aflatoxin B_(1)(AFB_(1))is a naturally-occurring mycotoxin and recognized as the most toxic foodborne toxin,particularly causing damages to kidney.Glomerular podocytes are terminally differentiated epithelial cells.AFB_(1)induces podocyte inflammation,proteinuria and renal dysfunction.Studying the mechanism of AFB_(1)-induced podocyte inflammation and murine kidney dysfunction,we detected that AFB_(1)increased ubiquitindependent degradation of the transcription factor RelA through enhanced interaction of RelA with E3 ubiquitin ligase tripartite motif containing 7(TRIM7)in mouse podocyte clone-5(MPC-5)and mouse glomeruli.Reduction of RelA resulted in decreasing microRNA-9(miR-9)and activating the chemokine receptor 4(CXCR4),thioredoxin interacting protein(TXNIP),and NOD-like receptor pyrin domain-containing 3(NLRP3)signaling axis(CXCR4/TXNIP/NLRP3 pathway),leading to podocyte inflammation.We also determined that downregulation of miR-9 led to CXCR4 expression and the downstream TXNIP/NLRP3 pathway activation.Overexpression of miR-9 or deletion of CXCR4 suppressed AFB_(1)-induced CXCR4/TXNIP/NLRP3 pathway,resulting in alleviating podocyte inflammation and kidney dysfunction.Our findings indicated that ubiquitin-dependent proteolysis of RelA,downregulation of miR-9,and activation of CXCR4/TXNIP/NLRP3 pathway played an essential role in AFB_(1)-induced glomerular podocyte inflammation.Our study revealed a novel mechanism,via RelA,for the control of AFB_(1)’s nephrotoxicity,leading to an effective protection of food safety and public health.

Stability and transepithelial transport of oligopeptide(KRQKYD)with hepatocyte-protective activity from Jinhua ham in human intestinal Caco-2 monolayer cells

The study evaluated the stability of an oligopeptide(Lys-Arg-Gln-Lys-Tyr-Asp,KRQKYD)and its transport mechanism by simulating gastrointestinal digestion and a model of human intestinal Caco-2 monolayer cells in vitro.In this study,the effects of environmental factors(temperature,pH and NaCl concentration)and simulated gastrointestinal digestion on the stability of KRQKYD were evaluated by indicators of the levels of alanine transaminase(ALT),aspartate transaminase(AST)and malondialdehyde(MDA)in an alcoholinduced hepatocyte injury model.The results showed that KRQKYD still maintained satisfactory hepatocyteprotective activity after treatment with different temperatures(20-80℃),pH(3.0-9.0),NaCl concentration(1%-7%)and simulated gastrointestinal digestion,which indicated that KRQKYD showed good stability to environmental factors and simulated gastrointestinal digestion.Furthermore,the intact KRQKYD could be absorbed in a model of Caco-2 monolayer cells with a P_(app)value of(9.70±0.53)×10^(-7)cm/s.Pretreatment with an energy inhibitor(sodium azide),a competitive peptide transporter inhibitor(Gly-Pro)and a transcytosis inhibitor wortmannin did not decrease the level of transepithelial KRQKYD transport,indicating that the transport mechanism of KRQKYD was not associated with energy dependent,vector mediated and endocytosis.The tight junction disruptor cytochalasin D significantly increased the level of transepithelial KRQKYD transport(P<0.05),suggesting that intact KRQKYD was absorbed by paracellular transport.

Effect of titin phosphorylation on degradation of titin from skeletal muscles

The degradation of titin could make the myofibrillar fragmentation to improve meat tenderization during postmortem.This study aimed to investigate effect of phosphorylation on titin degradation.Protein kinase A(PKA)and alkaline phosphatase(AP)were added to crude titin extracted from ovine longissimus lumborum(LL)muscles.Phosphorylated/dephosphorylated titin were incubated withμ-calpain at 4℃ for 2 days.Results showed titin in AP group started degradation earlier than that in PKA and control groups.There were 20,16 and 12 phosphorylated sites identified by iTRAQ in the PKA,control and AP group,respectively.3D structure of dephosphorylated titin fragment was simulated and its molecular dynamics trajectory analysis was performed using Discovery StudioTM.The dihedral angle in AP group was less and the dephosphorylated fragment had a higher kinetic energy and total energy.We suggested that changes caused by AP treatment might make titin unstable,which easily degraded byμ-calpain.

Green Synthesis, Composition Analysis and Surface Active Properties of Sodium Cocoyl Glycinate

Cocoyl glycine was synthesized directly from coconut oil and sodium glycinate in yield of 87%. IR, ESI-MS and LC/MS analysis results showed that cocoyl glycine consists of a series of acyl glycines with different acyl chain lengths, and the proportion of each component was consistent with the composition of fatty acids derived from coconut oil. The surface tension and the Critical Micelle Concentration (CMC) of corresponding sodium salt were evaluated. The result showed that sodium cocoyl glycinate reduced the surface tension of water to a minimum value of approximately 33 mN·m-1 at CMC of 0.21 mmol·L-1.

Stimulation impact of electric currents on heterotrophic denitrifying microbial viability and denitrification performance in high concentration nitrate-contaminated wastewater

Electric current stimulation has been shown to have a positive influence on heterotrophic denitrifying microbial viability and has the potential to improve wastewater denitrification performance. This study investigated the effects of varying current densities on microbial activity and NO_3^- removal efficiency under heterotrophic conditions.NO_3^-removal rate was highest at an applied current density of 400 mA/m^2. However, the optimum removal efficiency of total inorganic nitrogen(TIN; 99%) was achieved when the current density was fixed at 200 m A/m^2. Accumulation of NH_4^+-N and NO_2^--N byproducts were also minimized at this current density. The activity of heterotrophic denitrifying microorganisms was much higher at both 200 and 400 mA/m^2. Moreover, the average adenosine-5′-triphosphate(ATP)content(an indicator of cell metabolism) at a current density of 1600 mA/m^2 was lower than that under no current, indicating heterotrophic denitrifying microbial activity can be inhibited at high current densities. Hence, direct electrical stimulation on the activity of heterotrophic denitrifying microorganisms in the developed system should be lower than 1600 mA/m^2. This study improves the understanding of electric current influence on heterotrophic denitrifying microorganisms and promotes the intelligent application of direct electrical stimulation on wastewater treatment processes.