By retaining the native distal His64 in sperm whale myoglobin （Mb）, a second distal histidine was engineered in Mb by mutating Leu29 to His29. The resultant mutant of L29H Mb exhibits an unusual enhanced peroxidase ...By retaining the native distal His64 in sperm whale myoglobin （Mb）, a second distal histidine was engineered in Mb by mutating Leu29 to His29. The resultant mutant of L29H Mb exhibits an unusual enhanced peroxidase activity with a positive cooperativity in comparison to that of wild type Mb. The new enzyme with two cooperative distal histidines has not been found in native peroxidase, which emohasizes a creation of the rational nmt^in doclan展开更多
TiO2 nanoparticles were homogeneously coated on multi-walled carbon nanotubes by hydrothermal deposition, this nanocomposite may be a promising material for myoglobin immobilization in view of its high biocompatibilit...TiO2 nanoparticles were homogeneously coated on multi-walled carbon nanotubes by hydrothermal deposition, this nanocomposite may be a promising material for myoglobin immobilization in view of its high biocompatibility and large surface. The glassy carbon electrode modified with Mb-TiO2/MWCNTs films exhibited a pair of weU defined, stable and nearly reversible cycle voltammetric peaks. The electron transfer between Mb and electrode surface, Ks of 3.08 s^-1, was greatly facilitated in the TiO2/ MWCNTs film. The electrocatalytic reductions of hydrogen peroxide were studied, the apparent Michaelis-Menten constant is calculated to be 83.10 μmol/L, which shows a large catalytic activity of Mb in the TiO2/MWCNTs film to H2O2.展开更多
Background:Acute kidney injury(AKI)is the main life-threatening complication of crush syndrome(CS),and myoglobin is accepted as the main pathogenic factor.The pattern recognition receptor retinoicacid-inducible gene I...Background:Acute kidney injury(AKI)is the main life-threatening complication of crush syndrome(CS),and myoglobin is accepted as the main pathogenic factor.The pattern recognition receptor retinoicacid-inducible gene I(RIG-I)has been reported to exert anti-viral effects function in the innate immune response.However,it is not clear whether RIG-I plays a role in CS-AKI.The present research was carried out to explore the role of RIG-I in CS-AKI.Methods:Sprague-Dawley rats were randomly divided into two groups:the sham and CS groups(n=12).After administration of anesthesia,the double hind limbs of rats in the CS group were put under a pressure of 3 kg for 16 h to mimic crush conditions.The rats in both groups were denied access to food and water.Rats were sacrificed at 12 h or 36 h after pressure was relieved.The successful establishment of the CS-AKI model was confirmed by serum biochemical analysis and renal histological examination.In addition,RNA sequencing was performed on rat kidney tissue to identify molecular pathways involved in CS-AKI.Furthermore,NRK-52 E cells were treated with 200μmol/L ferrous myoglobin to mimic CS-AKI at the cellular level.The cells and cell supernatant samples were collected at 6 h or 24 h.Small interfering RNAs(siRNA)was used to knock down RIG-I expression.The relative expression levels of molecules involved in the RIG-I pathway in rat kidney or cells samples were measured by quantitative real-time PCR(qPCR),Western blotting analysis,and immunohistochemistry(IHC)staining.Tumor necrosis factor-α(TNF-α)was d etected by ELISA.Co-immunoprecipitation(Co-IP)assays were used to detect the interaction between RIG-I and myoglobin.Results:RNA sequencing of CS-AKI rat kidney tissue revealed that the different expression of RIG-I signaling pathway.qPCR,Western blotting,and IHC assays showed that RIG-I,nuclear factor kappa-B(NF-κB)P65,p-P65,and the a poptotic marker caspase-3 and cleaved caspase-3 were up-regulated in the CS group(P<0.05).However,the levels of interferon regulatory factor 3(IRF3),p-IRF3 and the antiviral factor interferon-beta(IFN-β)showed no significant c hanges between the sham and CS groups.Co-IP assays showed the interaction between RIG-I and myoglobin in the kidneys of the CS group.Depletion of RIG-I could alleviate the myoglobin induced expression of apoptosis-associated molecules via the NF-κB/caspase-3 axis.C onclusions:RIG-I is a novel damage-associated molecular patterns(DAMPs)sensor for myoglobin and participates in the NF-κB/caspase-3 signaling pathway in CS-AKI.In the development of CS-AKI,specific intervention in the RIG-I p athway might be a potential therapeutic strategy for CS-AKI.展开更多
Ordered films were made by casting a mixture of aqueous dispersions of didodecyldimethylammonium bromide (DDAB)-clay composite and myoglobin (Mb) solution on pyrolytic graphite (PG) electrodes. The Mb-DDAB-clay film e...Ordered films were made by casting a mixture of aqueous dispersions of didodecyldimethylammonium bromide (DDAB)-clay composite and myoglobin (Mb) solution on pyrolytic graphite (PG) electrodes. The Mb-DDAB-clay film electrodes showed stable and reversible cyclic voltammetric responses in buffers and can catalyze the reduction of id (TCA).展开更多
Direct electrochemistry and electrocatalysis of myoglobin（Mb） were studied with Mb immobilized on dodecyltrimethylammonium bromide（DTAB） film modified carbon ceramic（CC） electrode.Cyclic voltammetry showed a pai...Direct electrochemistry and electrocatalysis of myoglobin（Mb） were studied with Mb immobilized on dodecyltrimethylammonium bromide（DTAB） film modified carbon ceramic（CC） electrode.Cyclic voltammetry showed a pair of well-defined and nearly reversible redox peaks of Mb（Fe~Ⅱ/Fe~Ⅲ） at about—0.3 V vs.SCE（pH = 6.98）.The currents of the redox peak were linear to scan rate,and rate constant（Ks） was estimated to be 3.03 s^（-1）.The formal potential（E°＇） of Mb in the DTAB/CC electrodes shifted linearly with pH with a slope of -36.44 mV/pH,implying that the electron transfer between DTAB and CC electrodes is accompanied by proton transportation.The immobilized Mb exhibited excellent electrocatalytic response to the reduction of hydrogen peroxide（H2O2）.展开更多
The characteristic of Myoglobin as mimetic enzyme was studied and applied in the determination of HeO2 with o-phenylenediamine as substrate. The absorbanee obtained at 40 ℃ was found to be proportional to the concent...The characteristic of Myoglobin as mimetic enzyme was studied and applied in the determination of HeO2 with o-phenylenediamine as substrate. The absorbanee obtained at 40 ℃ was found to be proportional to the concentration of H2O2 in the range of 2.0×10^-5- 2.0×10^-7 mol/L, with a correlation coefficient of 0.999 1. The proposed meth od is simple and highly sensitive to a detection limit of 2.7 × 10^-8 mol/L. The relative standard deviations were within 5% for the determination of different concentrations of H2O2. Satisfied results were obtained in the determination of H2O2 in rainwater by this method, and the recoveries were at the range of 97.2%-105.4%.展开更多
Background: The possibility exists that cocaine use in the absence of frank clinical presentation of acute cardiac events may be associated with subclinical injury including the release of myoglobin which is a nonspec...Background: The possibility exists that cocaine use in the absence of frank clinical presentation of acute cardiac events may be associated with subclinical injury including the release of myoglobin which is a nonspecific marker for cardiac and skeletal muscle damage. Objectives: This investigation examined urine specimens for potential differences between cocaine use and the expression of myoglobin (a marker associated with cardiovascular damage, inflammation and oxidative stress). Methods:40 urine specimens were assayed for cocaine metabolites, creatinine, total protein (BSA) and myoglobin using ELISA and colorimetry. Results: We observed significant differences between male control and male cocaine positive urines for myoglobin. Interestingly, there was no statistically significant difference in females between control and cocaine positive urines. Conclusion: Differences in the urinary expression of myoglobin may be important in evaluating the gender based effects of cocaine use and may have potential clinical applications which may be related to gender differences in signs and symptoms of cocaine toxicity.展开更多
In order to elucidate the phylogenetic relationship of fish, DNA and deduced amino acid sequences of myoglobin （Mb） were used for the phylogenetic analyses based on different approaches, namely, maximum likelihood ...In order to elucidate the phylogenetic relationship of fish, DNA and deduced amino acid sequences of myoglobin （Mb） were used for the phylogenetic analyses based on different approaches, namely, maximum likelihood （ML）, neighbor joining （NJ）, unweighted pair group method with arithmetic means （UPGMA） and maximum parsimony （MP） methods in comparison with the conventional molecular markers, mitochondrial cytochrome b （cyt-b） and cytochrome c oxidase subunit I （COI）. The phylogenetic trees drawn based on Mb sequences were similar to those by the traditional classification based on the other molecular markers. The primary and secondary structures, as well as the modeled tertiary structures of Mbs were similar to each other, but were clearly distinguishable among those species. Such differences in structure would be associated with adaptation of Mb molecule to the physiological conditions of each species. These results suggest that Mb can be a molecular marker for the phylogenetic relationship of fish.展开更多
Myoglobin(Mb)mediates oxygen diffusion and storage in muscle tissue and thus is important for the energy utilization and activity of animals.Birds generally have a high body temperature,and most species also possess t...Myoglobin(Mb)mediates oxygen diffusion and storage in muscle tissue and thus is important for the energy utilization and activity of animals.Birds generally have a high body temperature,and most species also possess the capability of powered flight.Both of these require high levels of aerobic metabolism.Within endothermic mammals,bats also independently evolved flight.Although the functional evolution of myoglobins in deep-diving amniote vertebrates has been well-studied,the functional evolution of myoglobin since the origins of both birds and bats is unclear.Here,with Mb-coding sequences from>200 extant amniote species,we reconstructed ancestral sequences to estimate the functional properties of myoglobin through amniote evolution.A dramatic change in net surface charge on myoglobin occurred during the origin of Aves,which might have been driven by positively selected amino acid substitutions that occurred on the lineage leading to all birds.However,in bats,no change in net surface charge occurred and instead,the Mb genes show evidence of strong purifying selection.The increased net surface charge on bird myoglobins implies an adaptation to flight-related endothermic and higher body temperatures,possibly by reducing harmful protein aggregations.Different from the findings of net surface charge,myoglobins of extant birds show lower stability compared with other amniotes,which probably accelerates the rate of oxygen utilization in muscles.In bats and other mammals,higher stability of Mb may be an alternative pathway for adaptation to endothermy,indicating divergent evolution of myoglobin in birds and bats.展开更多
A photo-induced de-oxygenation process of myoglobin (Mb) in aqueous solution was investigated by use of fluorescence spectroscopy. The spectra are characterized by the fluorescence intensity declining gradually after ...A photo-induced de-oxygenation process of myoglobin (Mb) in aqueous solution was investigated by use of fluorescence spectroscopy. The spectra are characterized by the fluorescence intensity declining gradually after each scan,and the decay of fluorescence intensity being significant in each scan,which is assigned to the release of oxygen from the opening of the heme-pockets induced by illumination. More illumination will cause more release of oxygen; if the temperature of an Mb solution is increased when it is illuminated,the rate of de-oxygenation will be higher. It was found that ligand-oxygen in Fe-porphyrin could be removed from Mb by nitrogen. This indicates that the interac-tion between oxy-Mb and other different gases can be tested by the method of fluorescence spectros-copy. In addition,fluorescence spectroscopy can be employed to probe the energy transfer between Fe-porphyrin and tryptophan or tyrosine in Mb molecules.展开更多
A novel biosensor based on a myoglobin/gold nanoparticles/carbon spheres(Mb AuNPs CNs)3-D architecture bioconjunction has been fabricated for the determination of hydrogen peroxide(H2O2).Cyclic voltammetry(CV),Fourier...A novel biosensor based on a myoglobin/gold nanoparticles/carbon spheres(Mb AuNPs CNs)3-D architecture bioconjunction has been fabricated for the determination of hydrogen peroxide(H2O2).Cyclic voltammetry(CV),Fourier transform infrared(FT-IR)spectroscopy and scanning electron microscopy(SEM)were used to characterize the bioconjunction of the AuNPs CNs with Mb.Experimental results demonstrate that the AuNPsCNs hybrid material is more effective in facilitating electron transfer of the immobilized enzyme than CNs alone,which can be attributed to the unique nanostructure and larger surface area of the bioconjunction.The biosensor displayed good performance for the detection of H_(2)O_(2)with a wide linear range from 0.28μmol/L to 116.5μmol/L and a detection limit of 0.12μmol/L.The Michaelis-Menten constant KMapp value was estimated to be 0.3 mmol/L.The resulting biosensor exhibited fast amperometric response,and good stability,reproducibility,and selectivity to H_(2)O_(2).展开更多
Background Myoglobin is expressed exclusively in striated skeletal muscles and has been implicated in nitric oxide scavenging. Accumulating data suggest a critical role for nitric oxide in both the endogenous and ther...Background Myoglobin is expressed exclusively in striated skeletal muscles and has been implicated in nitric oxide scavenging. Accumulating data suggest a critical role for nitric oxide in both the endogenous and therapeutic angiogenic response to ischemia. A clear role for myoglobin in ischemic skeletal muscle is uncertain. We hypothesized that myoglobin overexpression has an adverse impact on the angiogenic response to ischemia. Methods Muscle-specific myoglobin over-expressing transgenic mice （MbTG, n=11）, wild type littermates （WT, n=23） underwent unilateral femoral artery ligation and excision. Laser doppler perfusion imaging was used to monitor changes in hindlimb perfusion before surgery and weekly after surgery up to 28 days. 13ssue ischemia was assessed by a necrosis incidence. Upon termination of the experiment （28 days after surgery）, skeletal muscles （gastrocnemius, and tibialis anterior） were harvested, the distal part of the muscle was frozen and embedded for histology study, the proximal part was used either to detect vascular endothelial growth factor （VEGF） level with enzyme-linked immunosorbent assays （ELISA） or to determine the proliferation （proliferating cell nuclear antigen （PCNA）） and apoptosis （Bax, and Bci-2） condition in ischemic muscle by Western blotting. Capillaries were stained with endothelial phosphate alkaline staining and vascular density was expressed in capillaries/fiber. Results The recovery of perfusion in MbTG mice was similar to that of WT mice on day 7 （0.485±0.095 vs 0.500±0.084） but was significantly less on day 14 （0.536±0.086 vs 0.623±0.077, P 〈0.05）, day 21 （0.588±0.082 vs 0.684±0.068, P 〈0.01） and day 28 （0.606±0.079 vs 0.733±0.093, P 〈0.01）. The necrosis incidence was higher in MbTG than in wr （54.5% vs 21.6%）. Vascular density was less in MbTG compared with that in WT （gastrocnemius 0.19±0.08 vs 0.30±0.08, P 〈0.05; tibialis anterior 0.22±0.11 vs 0.33±0.04, P 〈0.05）. With ischemic injury, the VEGF level was increased in both MbTG and wr （45.2% and 20.4%, respectively）. Western blotting showed that after hindlimb ischemia the proliferation was similar in both MbTG and WT, however, apoptosis was increased in MbTG relative to WT, shown as more expression of Bax and less expression of Bcl-2. Conclusion An increase in expression of myoglobin protein in skeletal muscle reduces the endogenous perfusion recovery following surgically induced hind-limb ischemia.展开更多
Hemoprotein molecules exhibit so slow electron transfer that no apparent currents appear at conventional electrodes because of either their extended three-dimensional structure and the reusltant inaccessibility to the...Hemoprotein molecules exhibit so slow electron transfer that no apparent currents appear at conventional electrodes because of either their extended three-dimensional structure and the reusltant inaccessibility to the electroactive centre or their strong adsorption onto the electrode surface for subsequent passivation. Chemically modified electrode (CME)made by adsporption of the phenothiazine methylene blue onto electrode was used for catalysis of hemoprotein electrode reactions in spectroelectrochemical study and in analysis of flow systems.展开更多
Myoglobin produced by fermentation using engineered Komagataella phaffii is an important color additive in meat analogue products,but its allergenicity is poorly understood.Here,we initially searched the Allergen Onli...Myoglobin produced by fermentation using engineered Komagataella phaffii is an important color additive in meat analogue products,but its allergenicity is poorly understood.Here,we initially searched the Allergen Online database and did not find any allergic or cross-reactive proteins in porcine myoglobin(PM).In vitro simulated digestion demonstrated that PM did not exhibit notable acid-base resistance or anti-digestion capabilities.However,sensitization was observed in BALB/c mice,including a significant increase in specific antibodies and biomarkers for allergic reactions,as well as alterations in gut microbiome and serum metabolome.Interestingly,the intensity of sensitization exhibited a negative correlation with the purity of PM.60%and 88%purities showed weaker sensitization compared to the ovalbumin control group.These allergic reactions were likely due to the non-myoglobin protein portion,highlighting the importance of purification processes and the urgent need to assess the allergenicity of this portion.展开更多
Myoglobin, myosin creatine kinase MM (CK-MM),creatine kinase BB(CK-BB) in cardiac muscle and H chain ofmyosin in atrial and ventricular muscle were studied in speci-mens from 8 patients who died of sudden nocturnal de...Myoglobin, myosin creatine kinase MM (CK-MM),creatine kinase BB(CK-BB) in cardiac muscle and H chain ofmyosin in atrial and ventricular muscle were studied in speci-mens from 8 patients who died of sudden nocturnal deathsyndrome(SNDS) by avidin-biotin complex (ABC) method toinvestigate the possible early or very early myocardial ischemiain the syndrome. Hematoxylin-eosin staining was conductedfor comparison. The results showed evident loss of CK-MM,CK-BB, myoglobin and myosin from cardiac muscle cells, indi-caring that occurrence of SNDS is closely associated withacute myocardial ischemia.展开更多
This paper reports the use of an electrochemically polymerized Toluidine Blue (TB) film electrode.The film on platinum electrode surface was analyzed with ESCA.The heterogeneous electron transfer processes of myoglobi...This paper reports the use of an electrochemically polymerized Toluidine Blue (TB) film electrode.The film on platinum electrode surface was analyzed with ESCA.The heterogeneous electron transfer processes of myoglobin at the polymerized TB film electrode have been investigated using in situ UV-visible spectroelectrochemistry.The formal potential(E°′)and electron transfer number(n)of myoglobin were calculated as E°′=0.045 V(vs.NHE)and n=0.99.The exhaustive reduction and oxidation electrolyses are achieved in 130 s and 110 s respectively,during a potential step between-0.4 V and+0.4 V.A formal heterogeneous electron transfer rate constant(ksh)of 1.09× 10^(-4) cm/s and a transfer coefficient(α)of 0.47 were obtained by cyclic voltabsorptometry,which indicated that myoglobin underwent a quasi-reversible electrode process at the polymerized TB film electrode.展开更多
基金supported by the National Natural Science Foundation of China,NSFC(No.21101091)Hunan Provincial Natural Science Foundation(No.11JJ4017)+1 种基金Hunan Provincial Education Foundation(No.11B105)the initial foundation for oversea scholar return to University of South China(No.2011XQD16)
文摘By retaining the native distal His64 in sperm whale myoglobin （Mb）, a second distal histidine was engineered in Mb by mutating Leu29 to His29. The resultant mutant of L29H Mb exhibits an unusual enhanced peroxidase activity with a positive cooperativity in comparison to that of wild type Mb. The new enzyme with two cooperative distal histidines has not been found in native peroxidase, which emohasizes a creation of the rational nmt^in doclan
基金the National Natural Science Foundation of China(No.20635020,90606016)
文摘TiO2 nanoparticles were homogeneously coated on multi-walled carbon nanotubes by hydrothermal deposition, this nanocomposite may be a promising material for myoglobin immobilization in view of its high biocompatibility and large surface. The glassy carbon electrode modified with Mb-TiO2/MWCNTs films exhibited a pair of weU defined, stable and nearly reversible cycle voltammetric peaks. The electron transfer between Mb and electrode surface, Ks of 3.08 s^-1, was greatly facilitated in the TiO2/ MWCNTs film. The electrocatalytic reductions of hydrogen peroxide were studied, the apparent Michaelis-Menten constant is calculated to be 83.10 μmol/L, which shows a large catalytic activity of Mb in the TiO2/MWCNTs film to H2O2.
基金supported by the Tianjin UniversityaDouble First Classoconstruction talent start-up fund to Dr.Yan-Hua Gong,the grants awarded to Shi-Ke Hou by Science and Technology Commission of the CMC(c12019048)Ning Li by Open Fund of State Key Laboratory of Medicinal Chemical Biology(Nankai University)(2020010)。
文摘Background:Acute kidney injury(AKI)is the main life-threatening complication of crush syndrome(CS),and myoglobin is accepted as the main pathogenic factor.The pattern recognition receptor retinoicacid-inducible gene I(RIG-I)has been reported to exert anti-viral effects function in the innate immune response.However,it is not clear whether RIG-I plays a role in CS-AKI.The present research was carried out to explore the role of RIG-I in CS-AKI.Methods:Sprague-Dawley rats were randomly divided into two groups:the sham and CS groups(n=12).After administration of anesthesia,the double hind limbs of rats in the CS group were put under a pressure of 3 kg for 16 h to mimic crush conditions.The rats in both groups were denied access to food and water.Rats were sacrificed at 12 h or 36 h after pressure was relieved.The successful establishment of the CS-AKI model was confirmed by serum biochemical analysis and renal histological examination.In addition,RNA sequencing was performed on rat kidney tissue to identify molecular pathways involved in CS-AKI.Furthermore,NRK-52 E cells were treated with 200μmol/L ferrous myoglobin to mimic CS-AKI at the cellular level.The cells and cell supernatant samples were collected at 6 h or 24 h.Small interfering RNAs(siRNA)was used to knock down RIG-I expression.The relative expression levels of molecules involved in the RIG-I pathway in rat kidney or cells samples were measured by quantitative real-time PCR(qPCR),Western blotting analysis,and immunohistochemistry(IHC)staining.Tumor necrosis factor-α(TNF-α)was d etected by ELISA.Co-immunoprecipitation(Co-IP)assays were used to detect the interaction between RIG-I and myoglobin.Results:RNA sequencing of CS-AKI rat kidney tissue revealed that the different expression of RIG-I signaling pathway.qPCR,Western blotting,and IHC assays showed that RIG-I,nuclear factor kappa-B(NF-κB)P65,p-P65,and the a poptotic marker caspase-3 and cleaved caspase-3 were up-regulated in the CS group(P<0.05).However,the levels of interferon regulatory factor 3(IRF3),p-IRF3 and the antiviral factor interferon-beta(IFN-β)showed no significant c hanges between the sham and CS groups.Co-IP assays showed the interaction between RIG-I and myoglobin in the kidneys of the CS group.Depletion of RIG-I could alleviate the myoglobin induced expression of apoptosis-associated molecules via the NF-κB/caspase-3 axis.C onclusions:RIG-I is a novel damage-associated molecular patterns(DAMPs)sensor for myoglobin and participates in the NF-κB/caspase-3 signaling pathway in CS-AKI.In the development of CS-AKI,specific intervention in the RIG-I p athway might be a potential therapeutic strategy for CS-AKI.
文摘Ordered films were made by casting a mixture of aqueous dispersions of didodecyldimethylammonium bromide (DDAB)-clay composite and myoglobin (Mb) solution on pyrolytic graphite (PG) electrodes. The Mb-DDAB-clay film electrodes showed stable and reversible cyclic voltammetric responses in buffers and can catalyze the reduction of id (TCA).
基金supported by the Shaanxi Provincial Natural Science Foundation for Young Scientist(No. 2009JQ2011)the Shaanxi Provincial Education Department Foundation(No.08JK322)+1 种基金the Youth Science and Technology Foundation of Xi'an University of Architecture and Technology(No.QN0620)Youth Scientist Foundation of Xi'an University of Architecture and Technology(No.RC0942)
文摘Direct electrochemistry and electrocatalysis of myoglobin（Mb） were studied with Mb immobilized on dodecyltrimethylammonium bromide（DTAB） film modified carbon ceramic（CC） electrode.Cyclic voltammetry showed a pair of well-defined and nearly reversible redox peaks of Mb（Fe~Ⅱ/Fe~Ⅲ） at about—0.3 V vs.SCE（pH = 6.98）.The currents of the redox peak were linear to scan rate,and rate constant（Ks） was estimated to be 3.03 s^（-1）.The formal potential（E°＇） of Mb in the DTAB/CC electrodes shifted linearly with pH with a slope of -36.44 mV/pH,implying that the electron transfer between DTAB and CC electrodes is accompanied by proton transportation.The immobilized Mb exhibited excellent electrocatalytic response to the reduction of hydrogen peroxide（H2O2）.
基金Supported by the National Natural Science Foun-dation of China (20275027) the Natural Science Foundation ofHubei Province (2004ABA182) .
文摘The characteristic of Myoglobin as mimetic enzyme was studied and applied in the determination of HeO2 with o-phenylenediamine as substrate. The absorbanee obtained at 40 ℃ was found to be proportional to the concentration of H2O2 in the range of 2.0×10^-5- 2.0×10^-7 mol/L, with a correlation coefficient of 0.999 1. The proposed meth od is simple and highly sensitive to a detection limit of 2.7 × 10^-8 mol/L. The relative standard deviations were within 5% for the determination of different concentrations of H2O2. Satisfied results were obtained in the determination of H2O2 in rainwater by this method, and the recoveries were at the range of 97.2%-105.4%.
文摘Background: The possibility exists that cocaine use in the absence of frank clinical presentation of acute cardiac events may be associated with subclinical injury including the release of myoglobin which is a nonspecific marker for cardiac and skeletal muscle damage. Objectives: This investigation examined urine specimens for potential differences between cocaine use and the expression of myoglobin (a marker associated with cardiovascular damage, inflammation and oxidative stress). Methods:40 urine specimens were assayed for cocaine metabolites, creatinine, total protein (BSA) and myoglobin using ELISA and colorimetry. Results: We observed significant differences between male control and male cocaine positive urines for myoglobin. Interestingly, there was no statistically significant difference in females between control and cocaine positive urines. Conclusion: Differences in the urinary expression of myoglobin may be important in evaluating the gender based effects of cocaine use and may have potential clinical applications which may be related to gender differences in signs and symptoms of cocaine toxicity.
文摘In order to elucidate the phylogenetic relationship of fish, DNA and deduced amino acid sequences of myoglobin （Mb） were used for the phylogenetic analyses based on different approaches, namely, maximum likelihood （ML）, neighbor joining （NJ）, unweighted pair group method with arithmetic means （UPGMA） and maximum parsimony （MP） methods in comparison with the conventional molecular markers, mitochondrial cytochrome b （cyt-b） and cytochrome c oxidase subunit I （COI）. The phylogenetic trees drawn based on Mb sequences were similar to those by the traditional classification based on the other molecular markers. The primary and secondary structures, as well as the modeled tertiary structures of Mbs were similar to each other, but were clearly distinguishable among those species. Such differences in structure would be associated with adaptation of Mb molecule to the physiological conditions of each species. These results suggest that Mb can be a molecular marker for the phylogenetic relationship of fish.
基金funded by grants from the China Postdoctoral Science Foundation(2021M702063)the Natural Science Basic Research Program of Shaanxi(2022JQ-169)to S.S.+2 种基金the National Natural Science Foundation of China(32270462)to Y.L.the Guangdong Natural Science Funds for Distinguished Young Scholar(2022B1515020033)the National Natural Science Foundation of China(32170452,31970389)to K.H.
文摘Myoglobin(Mb)mediates oxygen diffusion and storage in muscle tissue and thus is important for the energy utilization and activity of animals.Birds generally have a high body temperature,and most species also possess the capability of powered flight.Both of these require high levels of aerobic metabolism.Within endothermic mammals,bats also independently evolved flight.Although the functional evolution of myoglobins in deep-diving amniote vertebrates has been well-studied,the functional evolution of myoglobin since the origins of both birds and bats is unclear.Here,with Mb-coding sequences from>200 extant amniote species,we reconstructed ancestral sequences to estimate the functional properties of myoglobin through amniote evolution.A dramatic change in net surface charge on myoglobin occurred during the origin of Aves,which might have been driven by positively selected amino acid substitutions that occurred on the lineage leading to all birds.However,in bats,no change in net surface charge occurred and instead,the Mb genes show evidence of strong purifying selection.The increased net surface charge on bird myoglobins implies an adaptation to flight-related endothermic and higher body temperatures,possibly by reducing harmful protein aggregations.Different from the findings of net surface charge,myoglobins of extant birds show lower stability compared with other amniotes,which probably accelerates the rate of oxygen utilization in muscles.In bats and other mammals,higher stability of Mb may be an alternative pathway for adaptation to endothermy,indicating divergent evolution of myoglobin in birds and bats.
基金the National Natural Science Foundation of China (Grant No. 2021010)Program for Liaoning Excellent Talents in University (Grant No. RC-04-10)
文摘A photo-induced de-oxygenation process of myoglobin (Mb) in aqueous solution was investigated by use of fluorescence spectroscopy. The spectra are characterized by the fluorescence intensity declining gradually after each scan,and the decay of fluorescence intensity being significant in each scan,which is assigned to the release of oxygen from the opening of the heme-pockets induced by illumination. More illumination will cause more release of oxygen; if the temperature of an Mb solution is increased when it is illuminated,the rate of de-oxygenation will be higher. It was found that ligand-oxygen in Fe-porphyrin could be removed from Mb by nitrogen. This indicates that the interac-tion between oxy-Mb and other different gases can be tested by the method of fluorescence spectros-copy. In addition,fluorescence spectroscopy can be employed to probe the energy transfer between Fe-porphyrin and tryptophan or tyrosine in Mb molecules.
基金We greatly appreciate the support of the National Natural Science Foundation of China under the Key Program(20635020)Creative Research Group(20521503)+2 种基金General Program(90606016)This work is also supported by National Basic Research Program of China(2006CB933201)the European Community Sixth Framework Program through a STREP Grant to the SELECTNANO Consortium,Contract No.516922.
文摘A novel biosensor based on a myoglobin/gold nanoparticles/carbon spheres(Mb AuNPs CNs)3-D architecture bioconjunction has been fabricated for the determination of hydrogen peroxide(H2O2).Cyclic voltammetry(CV),Fourier transform infrared(FT-IR)spectroscopy and scanning electron microscopy(SEM)were used to characterize the bioconjunction of the AuNPs CNs with Mb.Experimental results demonstrate that the AuNPsCNs hybrid material is more effective in facilitating electron transfer of the immobilized enzyme than CNs alone,which can be attributed to the unique nanostructure and larger surface area of the bioconjunction.The biosensor displayed good performance for the detection of H_(2)O_(2)with a wide linear range from 0.28μmol/L to 116.5μmol/L and a detection limit of 0.12μmol/L.The Michaelis-Menten constant KMapp value was estimated to be 0.3 mmol/L.The resulting biosensor exhibited fast amperometric response,and good stability,reproducibility,and selectivity to H_(2)O_(2).
基金This research was supported by the grants from the National Nature Science Foundation of China （No. 30772114） and the Scientific Research Foundation for Returned Overseas Chinese Scholars, State Personnel Ministry.Acknowledgments： The authors acknowledge professor Brian H. Annex, MD, for his kind direction on the whole experiment. We also acknowledge Daniel D. Lantvit, Shelley Odronic, Erika Reed, ZHU Shou-kang, WU Ka-ren, and Conrad Ireland for their assistance.
文摘Background Myoglobin is expressed exclusively in striated skeletal muscles and has been implicated in nitric oxide scavenging. Accumulating data suggest a critical role for nitric oxide in both the endogenous and therapeutic angiogenic response to ischemia. A clear role for myoglobin in ischemic skeletal muscle is uncertain. We hypothesized that myoglobin overexpression has an adverse impact on the angiogenic response to ischemia. Methods Muscle-specific myoglobin over-expressing transgenic mice （MbTG, n=11）, wild type littermates （WT, n=23） underwent unilateral femoral artery ligation and excision. Laser doppler perfusion imaging was used to monitor changes in hindlimb perfusion before surgery and weekly after surgery up to 28 days. 13ssue ischemia was assessed by a necrosis incidence. Upon termination of the experiment （28 days after surgery）, skeletal muscles （gastrocnemius, and tibialis anterior） were harvested, the distal part of the muscle was frozen and embedded for histology study, the proximal part was used either to detect vascular endothelial growth factor （VEGF） level with enzyme-linked immunosorbent assays （ELISA） or to determine the proliferation （proliferating cell nuclear antigen （PCNA）） and apoptosis （Bax, and Bci-2） condition in ischemic muscle by Western blotting. Capillaries were stained with endothelial phosphate alkaline staining and vascular density was expressed in capillaries/fiber. Results The recovery of perfusion in MbTG mice was similar to that of WT mice on day 7 （0.485±0.095 vs 0.500±0.084） but was significantly less on day 14 （0.536±0.086 vs 0.623±0.077, P 〈0.05）, day 21 （0.588±0.082 vs 0.684±0.068, P 〈0.01） and day 28 （0.606±0.079 vs 0.733±0.093, P 〈0.01）. The necrosis incidence was higher in MbTG than in wr （54.5% vs 21.6%）. Vascular density was less in MbTG compared with that in WT （gastrocnemius 0.19±0.08 vs 0.30±0.08, P 〈0.05; tibialis anterior 0.22±0.11 vs 0.33±0.04, P 〈0.05）. With ischemic injury, the VEGF level was increased in both MbTG and wr （45.2% and 20.4%, respectively）. Western blotting showed that after hindlimb ischemia the proliferation was similar in both MbTG and WT, however, apoptosis was increased in MbTG relative to WT, shown as more expression of Bax and less expression of Bcl-2. Conclusion An increase in expression of myoglobin protein in skeletal muscle reduces the endogenous perfusion recovery following surgically induced hind-limb ischemia.
文摘Hemoprotein molecules exhibit so slow electron transfer that no apparent currents appear at conventional electrodes because of either their extended three-dimensional structure and the reusltant inaccessibility to the electroactive centre or their strong adsorption onto the electrode surface for subsequent passivation. Chemically modified electrode (CME)made by adsporption of the phenothiazine methylene blue onto electrode was used for catalysis of hemoprotein electrode reactions in spectroelectrochemical study and in analysis of flow systems.
基金supported by the National Natural Science Foundation of China(32125031)the National Key Research and Development Program of China(2021YFC2101400)+1 种基金the Fundamental Research Funds for the Central Universities(JUSRP222001)Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province,Jiangnan University.
文摘Myoglobin produced by fermentation using engineered Komagataella phaffii is an important color additive in meat analogue products,but its allergenicity is poorly understood.Here,we initially searched the Allergen Online database and did not find any allergic or cross-reactive proteins in porcine myoglobin(PM).In vitro simulated digestion demonstrated that PM did not exhibit notable acid-base resistance or anti-digestion capabilities.However,sensitization was observed in BALB/c mice,including a significant increase in specific antibodies and biomarkers for allergic reactions,as well as alterations in gut microbiome and serum metabolome.Interestingly,the intensity of sensitization exhibited a negative correlation with the purity of PM.60%and 88%purities showed weaker sensitization compared to the ovalbumin control group.These allergic reactions were likely due to the non-myoglobin protein portion,highlighting the importance of purification processes and the urgent need to assess the allergenicity of this portion.
文摘Myoglobin, myosin creatine kinase MM (CK-MM),creatine kinase BB(CK-BB) in cardiac muscle and H chain ofmyosin in atrial and ventricular muscle were studied in speci-mens from 8 patients who died of sudden nocturnal deathsyndrome(SNDS) by avidin-biotin complex (ABC) method toinvestigate the possible early or very early myocardial ischemiain the syndrome. Hematoxylin-eosin staining was conductedfor comparison. The results showed evident loss of CK-MM,CK-BB, myoglobin and myosin from cardiac muscle cells, indi-caring that occurrence of SNDS is closely associated withacute myocardial ischemia.
基金Project supported by the National Natural Science Foundation of China
文摘This paper reports the use of an electrochemically polymerized Toluidine Blue (TB) film electrode.The film on platinum electrode surface was analyzed with ESCA.The heterogeneous electron transfer processes of myoglobin at the polymerized TB film electrode have been investigated using in situ UV-visible spectroelectrochemistry.The formal potential(E°′)and electron transfer number(n)of myoglobin were calculated as E°′=0.045 V(vs.NHE)and n=0.99.The exhaustive reduction and oxidation electrolyses are achieved in 130 s and 110 s respectively,during a potential step between-0.4 V and+0.4 V.A formal heterogeneous electron transfer rate constant(ksh)of 1.09× 10^(-4) cm/s and a transfer coefficient(α)of 0.47 were obtained by cyclic voltabsorptometry,which indicated that myoglobin underwent a quasi-reversible electrode process at the polymerized TB film electrode.
