Heat-killed Lactobacillus murinus confers neuropro-tection against dopamine neuronal loss by targeting NLRP3 inflammasome / 中国药理学与毒理学杂志

OBJECTIVE In this study,the effects of live Lactobacillus murinus(L.m)and heat-killed L.muri-nus(H-k L.m)on DA neuronal damage in rats and the underlying mechanisms were investigated.METHODS Male SD rats were randomly divided into five groups:vehicle group,L.m/H-k L.m(1×109 cfu)group,6-OHDH group,6-OHDH + L.m/H-k L.m(1×107 cfu)group,and 6-OHDH + L.m/H-k L.m(1×109 cfu)group.Wild-type and NLRP3 knockout mice were divided into three groups:sham(vehicle),6-OHDH,and 6-OHDH + H-k L.m(1×109 cfu).The model was established after five weeks of pre-administration.Motor ability of experimental mice was assessed by rotarod,mine,and stepping experiments;the expression of dopaminergic neuron markers—tyro-sine hydroxylase(TH),microglial cell markers—ionized calnexin 1(IBA-1),and NOD-like receptor family protein 3(NLRP3)in the substantia nigra was detected by immunohistochemistry and immunofluorescence experi-ments.The expression changes of TH,IBA-1,NLRP3,apoptosis-associated microparticle protein(ASC),cas-pase 1,and inflammatory factors such as interleukin-1β(IL-1β),IL-18,and tumor necrosis factor-α(TNF-α)were detected by immunoblotting experiments.RESULTS H-k L.m ameliorated 6-OHDH-induced motor dysfunctions and loss of substantia nigra DA neurons,while no protec-tion was shown in live L.m treatment.At the same time,H-k L.m reduced the activation of NLRP3 inflammasome in microglia and the secretion of pro-inflammatory factors,thus inhibiting the development of neuroinflammation.Fur-thermore,H-k L.m failed to display its original neuropro-tective properties in NLRP3 inflammasome knockout mice.CONCLUSION H-k L.m conferred neuroprotec-tion against DA neuronal loss via the inhibition of microglial NLRP3 inflammasome activation,these findings provide a promising potential for future applications of L.m,and also beneficial strategy for PD treatment.

Production, purification and characterization of bacteriocin from Lactobacillus murinus AU06 and its broad antibacterial spectrum

Objective: To study the production, purification and characterization of bacteriocin fromLactobacillus murinus against fish pathogens.Methods:AU06 isolated from marine sediments and its broad spectrum of inhibition bacteriocin. In addition, purified bacteriocin was tested for its antimicrobial activity against fish pathogens.Results:In the present study, the bacteriocin production was found to be higher at 35 °C, pH The selected strain was used in production, purification and characterized of 6.0 and was purified to 4.74 fold with 55. 38 U/mg of specific activity with the yield of 28.92%. The molecular weight of the purified bacteriocin was estimated as 21 kDa. The purified bacteriocin exhibited complete inactivation of antimicrobial activity when treated with proteinase K, pronase, chymotrypsin, trypsin, pepsin and papain. The purified bacteriocin exhibited broad inhibitory spectrum against both Gram positive and negative bacteria.Conclusions:It is concluded that the ability of bacteriocin in inhibiting a wide-range of pathogenic bacteria is of potential interest for food safety and may have future applications in food preservative.

Production, purification and characterization of bacteriocin from Lactobacillus murinus AU06 and its broad antibacterial spectrum

<p><b>OBJECTIVE</b>To study the production, purification and characterization of bacteriocin from Lactobacillus murinus AU06 isolated from marine sediments and its broad spectrum of inhibition against fish pathogens.</p><p><b>METHODS</b>The selected strain was used in production, purification and characterized of bacteriocin. In addition, purified bacteriocin was tested for its antimicrobial activity against fish pathogens.</p><p><b>RESULTS</b>In the present study, the bacteriocin production was found to be higher at 35 °C, pH 6.0 and was purified to 4.74 fold with 55. 38 U/mg of specific activity with the yield of 28.92%. The molecular weight of the purified bacteriocin was estimated as 21 kDa. The purified bacteriocin exhibited complete inactivation of antimicrobial activity when treated with proteinase K, pronase, chymotrypsin, trypsin, pepsin and papain. The purified bacteriocin exhibited broad inhibitory spectrum against both Gram positive and negative bacteria.</p><p><b>CONCLUSIONS</b>It is concluded that the ability of bacteriocin in inhibiting a wide-range of pathogenic bacteria is of potential interest for food safety and may have future applications in food preservative.</p>