To explore the oxidation mechanism of wooden breast myofibrillar protein(WBMP),oxidative breast MP(OBMP)was obtained from different doses(3,10,and 20 mmol/L)of H2O2 oxidized normal breast MP(NBMP).The results showed t...To explore the oxidation mechanism of wooden breast myofibrillar protein(WBMP),oxidative breast MP(OBMP)was obtained from different doses(3,10,and 20 mmol/L)of H2O2 oxidized normal breast MP(NBMP).The results showed that the Zeta-potential,particle size,solubility,sulfhydryl,and carbonyl contents of OBMP-3(3 mmol/L,low-dose free radicals)and WBMP were similar.Fluorescence spectrum analysis showed that the oxidation of low-dose free radicals led to a significant increase in the surface hydrophobicity(from 214.03±10.03 to 393.50±10.33)and tryptophan fluorescence intensity(from 185.71 to 568.32).In addition,theα-helix content of WBMP decreased significantly from(37.46±1.15)%(NBMP)to(34.70±2.04)%,whileβ-sheet and random coil contents increased significantly(P<0.05)from(14.37±0.69)%and(22.24±0.78)%(NBMP)to(17.70±0.87)%and(25.20±1.47)%(WBMP).In summary,low-dose free radical oxidation attacks protein groups,inducing secondary and tertiary structural changes,leading to the formation of WBMP.This work will provide a theoretical basis at the molecular level for exploring the mechanism of functional degradation of WBMP.展开更多
The Mott insulator and superfluid phase transition is one of the most prominent phenomena in ultracold atoms.We report the observation of a novel 2D quantum phase transition between the Mott insulator andπsuperfluid ...The Mott insulator and superfluid phase transition is one of the most prominent phenomena in ultracold atoms.We report the observation of a novel 2D quantum phase transition between the Mott insulator andπsuperfluid in a shaking optical lattice.In the deep optical lattice regime,the lowest S band can be tuned to Mott phase,while the higher P_(x,y)bands are itinerant for having larger bandwidth.Through a shaking technique coupling the s-orbital to p_(x,y)-orbital states,we experimentally observe the transition between the states of the S and P_(x,y)bands,leading to a quantum phase transition from two-dimensional s-orbital Mott phase to the p_(x,y)-orbital superfluid which condensed at(π,π)momentum.Using the band-mapping method,we also observe the changes of atomic population in different energy bands during the transition,and the experimental results are well consistent with theoretical expectations.展开更多
Secretory phospholipase A2s(sPLA2s)are found in a wide range of organisms from bacteria to higher plants and animals and are involved in varied and cellular pro-cesses.However,roles of these enzymes in microbial patho...Secretory phospholipase A2s(sPLA2s)are found in a wide range of organisms from bacteria to higher plants and animals and are involved in varied and cellular pro-cesses.However,roles of these enzymes in microbial pathogens remain unclear.Here,an sPLA2(BbPLA2)was characterized in the filamentous insect pathogenic fungus,Beau-veria bassiana.BbPLA2was exclusively expressed in insect hemolymph-derived cells(hyphal bodies),and its expression was induced by insect-derived nutrients and lipids,and nutrient starvation.High levels of secretion of BbPLA2 were observed as well as its distri-bution in hyphal body lipid drops(LDs).Overexpression of BbPLA2 increased the ability of B.bassiana to utilize insect-derived nutrients and lipids,and promoted LD accumula-tion,indicating functions for BbPLA2 in mediating LD homeostasis and assimilation of insect-derived lipids.Strains overexpressing BbPLA2 showed moderately increased vir-ulence,including more efficient penetration of the insect cuticle and evasion of host im-mune responses as compared to the wild type strain.In addition,B.bassiana-activated host immune genes were downregulated in the BbPLA2 overexpression strain,but upregulated by infections with a△BbPLA2 strain.These data demonstrate that BbPLA2 contributes to LD homeostasis,assimilation of insect-derived lipids,and repression of host immune responses.展开更多
基金supported by the Shandong Modern Agricultural Technology and Industry System(SDAIT-11-11)China Agricultural Research System(CARS-41-Z06)Natural Science Foundation of Shandong Province(ZR2022MC087).
文摘To explore the oxidation mechanism of wooden breast myofibrillar protein(WBMP),oxidative breast MP(OBMP)was obtained from different doses(3,10,and 20 mmol/L)of H2O2 oxidized normal breast MP(NBMP).The results showed that the Zeta-potential,particle size,solubility,sulfhydryl,and carbonyl contents of OBMP-3(3 mmol/L,low-dose free radicals)and WBMP were similar.Fluorescence spectrum analysis showed that the oxidation of low-dose free radicals led to a significant increase in the surface hydrophobicity(from 214.03±10.03 to 393.50±10.33)and tryptophan fluorescence intensity(from 185.71 to 568.32).In addition,theα-helix content of WBMP decreased significantly from(37.46±1.15)%(NBMP)to(34.70±2.04)%,whileβ-sheet and random coil contents increased significantly(P<0.05)from(14.37±0.69)%and(22.24±0.78)%(NBMP)to(17.70±0.87)%and(25.20±1.47)%(WBMP).In summary,low-dose free radical oxidation attacks protein groups,inducing secondary and tertiary structural changes,leading to the formation of WBMP.This work will provide a theoretical basis at the molecular level for exploring the mechanism of functional degradation of WBMP.
基金supported by the National Natural Science Foundation of China(Grant Nos.11920101004,11934002)the National Key Research and Development Program of China(Grant Nos.2021YFA1400900,2021YFA0718300)。
文摘The Mott insulator and superfluid phase transition is one of the most prominent phenomena in ultracold atoms.We report the observation of a novel 2D quantum phase transition between the Mott insulator andπsuperfluid in a shaking optical lattice.In the deep optical lattice regime,the lowest S band can be tuned to Mott phase,while the higher P_(x,y)bands are itinerant for having larger bandwidth.Through a shaking technique coupling the s-orbital to p_(x,y)-orbital states,we experimentally observe the transition between the states of the S and P_(x,y)bands,leading to a quantum phase transition from two-dimensional s-orbital Mott phase to the p_(x,y)-orbital superfluid which condensed at(π,π)momentum.Using the band-mapping method,we also observe the changes of atomic population in different energy bands during the transition,and the experimental results are well consistent with theoretical expectations.
基金supported by a grant from the National Nature Science Foundation of China(31672080)。
文摘Secretory phospholipase A2s(sPLA2s)are found in a wide range of organisms from bacteria to higher plants and animals and are involved in varied and cellular pro-cesses.However,roles of these enzymes in microbial pathogens remain unclear.Here,an sPLA2(BbPLA2)was characterized in the filamentous insect pathogenic fungus,Beau-veria bassiana.BbPLA2was exclusively expressed in insect hemolymph-derived cells(hyphal bodies),and its expression was induced by insect-derived nutrients and lipids,and nutrient starvation.High levels of secretion of BbPLA2 were observed as well as its distri-bution in hyphal body lipid drops(LDs).Overexpression of BbPLA2 increased the ability of B.bassiana to utilize insect-derived nutrients and lipids,and promoted LD accumula-tion,indicating functions for BbPLA2 in mediating LD homeostasis and assimilation of insect-derived lipids.Strains overexpressing BbPLA2 showed moderately increased vir-ulence,including more efficient penetration of the insect cuticle and evasion of host im-mune responses as compared to the wild type strain.In addition,B.bassiana-activated host immune genes were downregulated in the BbPLA2 overexpression strain,but upregulated by infections with a△BbPLA2 strain.These data demonstrate that BbPLA2 contributes to LD homeostasis,assimilation of insect-derived lipids,and repression of host immune responses.
