Purpose:The aim of this study was to extend current half-sarcomere models by involving a recently found force-mediated activation of the thick filament and analyze the effect of this mechanosensing regulation on the l...Purpose:The aim of this study was to extend current half-sarcomere models by involving a recently found force-mediated activation of the thick filament and analyze the effect of this mechanosensing regulation on the length stability of half-sarcomeres arranged in series.Methods:We included a super-relaxed state of myosin motors and its force-dependent activation in a conventional cross-bridge model.We simulated active stretches of a sarcomere consisting of 2 non-uniform half-sarcomeres on the descending limb of the force-length relationship.Results:The mechanosensing model predicts that,in a passive sarcomere on the descending limb of the force-length relationship,the longer half-sarcomere has a higher fraction of myosin motors in the on-state than the shorter half-sarcomere.The difference in the number of myosin motors in the on-state ensures that upon calcium-mediated thin filament activation,the force-dependent thick filament activation keeps differences in active force within 20%during an active stretch.In the classical cross-bridge model,the corresponding difference exceeds 80%,leading to great length instabilities.Conclusion:Our simulations suggest that,in contrast to the classical cross-bridge model,the mechanosensing regulation is able to stabilize a system of non-uniform half-sarcomeres arranged in series on the descending limb of the force-length relationship.展开更多
Hypertrophic cardiomyopathy(HCM)is a major contributor to cardiovascular diseases(CVD),the leading cause of death globally.HCM can precipitate heart failure(HF)by causing the cardiac tissue to weaken and stretch,there...Hypertrophic cardiomyopathy(HCM)is a major contributor to cardiovascular diseases(CVD),the leading cause of death globally.HCM can precipitate heart failure(HF)by causing the cardiac tissue to weaken and stretch,thereby impairing its pumping efficiency.Moreover,HCM increases the risk of atrial fibrillation,which in turn elevates the likelihood of thrombus formation and stroke.Given these significant clinical ramifications,research into the etiology and pathogenesis of HCM is intensifying at multiple levels.In this review,we discuss and synthesize the latest findings on HCM pathogenesis,drawing on key experimental studies conducted both in vitro and in vivo.We also offer our insights and perspectives on these mechanisms,while highlighting the limitations of current research.Advancing fundamental research in this area is essential for developing effective therapeutic interventions and enhancing the clinical management of HCM.展开更多
Sarcomerogenesis,the addition of serial sarcomeres in skeletal muscle myofibrils and fibres,is a natural occurrence during growth and maturation of animals,including humans.However,the detailed mechanisms that allow f...Sarcomerogenesis,the addition of serial sarcomeres in skeletal muscle myofibrils and fibres,is a natural occurrence during growth and maturation of animals,including humans.However,the detailed mechanisms that allow for sarcomerogenesis are not fully understood.In some diseases,such as cerebral palsy in children,sarcomerogenesis appears to be inhibited or at least reduced,1,2 often causing severe restrictions in muscle and joint function.展开更多
The effects of xanthan gum (0 % and 0.3 %) on the quality of low sodium (2.0 %, 2.4 %, 2.8 %, 3.2 %, 3.6 % and 4.0 %) salted beef and property of myofibril proteins (MP) extracted from salted beef were researched. Cha...The effects of xanthan gum (0 % and 0.3 %) on the quality of low sodium (2.0 %, 2.4 %, 2.8 %, 3.2 %, 3.6 % and 4.0 %) salted beef and property of myofibril proteins (MP) extracted from salted beef were researched. Changes in the salting absorptivity, cooking loss, shear force, color and sensory analysis showed that xanthan gum had a positive effect on the quality of salted beef with low salinity (2.0 %, 2.4 % and 2.8 %). MP of salted beef treated with xanthan gum had higher solubility, lower hydrogen bond than that without it (P < 0.05). The decrease of surface hydrophobicity and intrinsic fluorescence intensity indicated that the chromophore of protein was brought into a hydrophobic environment in the presence of xanthan gum. The electrophoresis showed that xanthan gum could improve the concentration of myosin heavy chain, paramyosin and actin after tumble-salting. The data suggested that salted beef and its MP treated with xanthan gum and 2.8 % salt (XS3) had the best properties. Together, xanthan gum could be considered as a sodium salt substitute for the development of low sodium meat products.展开更多
Changes in tissue structure, rheological property and water content of dry abalone meat in the process of water restora- tion were studied. The weight and volume of dry abalone meat increased with water restoration. W...Changes in tissue structure, rheological property and water content of dry abalone meat in the process of water restora- tion were studied. The weight and volume of dry abalone meat increased with water restoration. When observed under a light micro- scope, structural change in myofibrils was obvious and a distinct network was found. When water restoration time increased from 24 h to 72 h, the instantaneous modulus E0 and viscosity η1 increased, whereas the rupture strength and relaxation time (τ1) were re- duced. There were no significant changes of rheological parameters (E0, η1, τ1, rupture strength) from 72 h to 96 h of water restoration. Therefore, the dry abalone meat was swollen enough at the time of 72 h. The rheological parameters were obviously influenced by the structural changes.展开更多
This study aimed to examine changes in phosphorylation of sarcoplasmic and myofibrillar proteins from longissimus lumborum,semitendinosus,and psoas major muscles during postmortem ageing for 5 d.These sarcoplasmic and...This study aimed to examine changes in phosphorylation of sarcoplasmic and myofibrillar proteins from longissimus lumborum,semitendinosus,and psoas major muscles during postmortem ageing for 5 d.These sarcoplasmic and myofibrillar proteins were separated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and stained with phosphorous and protein specific stains.Myofibril fragmentation index,pH,the content of lactic acid and the relative activity of μ-calpain in three ovine muscles were measured.These results showed that the relative phosphorylation level of sarcoplasmic and myofibrillar proteins of psoas major muscle were lower compared with longissimus lumborum and semitendinosus muscles(P<0.05).The pH of psoas major muscle was the lowest at 0.5 h postmortem,and the highest after 12 h postmortem(P<0.05).In addition,the relative activity of μ-calpain was higher within 5 d postmortem and myofibril fragmentation index was higher after 1 d postmortem in psoas major muscle than those of longissimus lumborum and semitendinosus muscles(P<0.05).The sarcoplasmic protein phosphorylation may regulate the rate of pH decline to influence the μ-calpain activity and then proteolysis of proteins consequently.This study gives a new perspective of the mechanism of postmortem meat tenderization.展开更多
The quantitative correlation between rheological properties and structural characteristic values of chilled abalone meat was studied. Structural changes were observed, and these values were enumerated using image proc...The quantitative correlation between rheological properties and structural characteristic values of chilled abalone meat was studied. Structural changes were observed, and these values were enumerated using image processing and analysis technique. Structural changes in the myofibrils and collagen fibrils were the greatest in chilling for 24 h. After chilling for 48h, similar structures of vertical and cross sections were observed. For chilling from 0h to 72h, the instantaneous modulus E0 of the both section meat decreases gradually with time, but no significant differences were observed after chilling for 48h. The relaxation time and viscosity of both sections attained the same values for the same chilling time, but increased gradually with increasing chilling time. Meanwhile, a negative correlation between the structural characteristic values (Dm, Am, Rvm), and rheological properties (E1, τ1 , η1) clearly exists. Some logarithmic expressions have been obtained for these negative correlations. These results suggest that the difference in rheological properties between the cross and vertical sections was mainly due to the structural changes of myofibrils and collagen fibrils, and rheological properties are influenced quantitatively by the structural characteristic values for chilling from 0h to 72h.展开更多
The degradation of structural proteins during fish postmortem storage is a critical factor affecting meat quality,leading to economic losses in the seafood industry.The complex interplay between caspase-3 and structur...The degradation of structural proteins during fish postmortem storage is a critical factor affecting meat quality,leading to economic losses in the seafood industry.The complex interplay between caspase-3 and structural protein stability during fish postmortem storage remains largely unexplored.By treating grass carp fillets with a caspase-3 inhibitor,we establish a model for inhibiting apoptosis,delineating the role of caspase-3 in protein degradation.The effect of caspase-3 on grass carp proteins following postmortem storage and its cascade interaction with calpain and cathepsin L was further investigated.The result demonstrated that the destabili-zation of the mitochondrial membrane during apoptosis led to modifications in the B-cell lymphoma(Bcl)family proteins,subsequently triggered the activation of caspase-9/caspase-3.Additionally,caspase-3 reduced the expression of the calpastatin and lysosomal membrane protein 1(LAMP-1)gene,resulting in increased calpain and cathepsin L activity.SDS-PAGE and liquid chromatography-tandem mass spectrometry(LC-MS/MS)analysis indicated that caspase-3 inhibitor treatment reduced actin fractures and preserved critical structural proteins.This investigation unveils the molecular mechanisms through which caspase-3 affects protein degradation in fish fillets during storage,providing valuable insights into the postmortem degradation processes.展开更多
The effects of traditional flame stewing(TFS),commercial pressure cooking(PC),and sous-vide cooking(SVC)on the texture of pork belly and the underlying mechanism were investigated.SVC treatment at a low temper-ature(6...The effects of traditional flame stewing(TFS),commercial pressure cooking(PC),and sous-vide cooking(SVC)on the texture of pork belly and the underlying mechanism were investigated.SVC treatment at a low temper-ature(60℃)achieved weaker oxidation of sulfhydryl groups,lowerα-helical loss,higher surface hydropho-bicity,and actomyosin dissociation,which reduced the shrinkage of myofibrils and loss of immobilized water,thus contributed to a tender meat.However,the protein aggregation predominated without actomyosin disso-ciation during PC treatment,causing the toughening of meat.TFS and PC intensified the atrophy of adipocytes and damage of cell membranes,which helped for the softening of adipose tissue and achieved 13.82%and 17.62%lipid loss,respectively,and contributed to a higher ratio of polyunsaturated fatty acids to saturated fatty acids(0.45-0.46)than SVC(0.34).Comparisons showed that TFS was a more suitable method to prepare cooked pork belly with tender and juicy texture,low lipid content,and high ratio of polyunsaturated fatty acids to saturated fatty acids.This study offered new insights into how cooking regimes affect the texture and lipid-lowering effects of stewed pork.展开更多
The short shelf-life of shrimp due to microbial activity and protein spoilage poses a threaten for preservation.In this study,the preservation effect of slightly acid electrolysed water(SAEW)combined with grape seed e...The short shelf-life of shrimp due to microbial activity and protein spoilage poses a threaten for preservation.In this study,the preservation effect of slightly acid electrolysed water(SAEW)combined with grape seed extract(GSE)was investigated.The combined treatment effectively inhibited the growth of spoilage bacteria including Aeromonas,Pseudomonas,Shewanella,and Enterobacteriaceae,which accounted for shrimp spoilage.Besides,the combination efficiently preserved the shrimp colour during storage.To further elucidate the preservative mechanism,the proteomic analysis was conducted,a total of 47 different abundant proteins(DAPs)were identified and quantified.Among these,the combination treatment was most effective in maintaining the main structural proteins presented in myofibrillar protein of shrimp including myosin heavy chain,myosin light chain,actin,and projectin,which was verified by the least changes in texture and protein morphology in combination treated shrimp after storage.These results provided proteomics insight for the preservative mechanism of combined usage of SAEW and GSE.展开更多
文摘Purpose:The aim of this study was to extend current half-sarcomere models by involving a recently found force-mediated activation of the thick filament and analyze the effect of this mechanosensing regulation on the length stability of half-sarcomeres arranged in series.Methods:We included a super-relaxed state of myosin motors and its force-dependent activation in a conventional cross-bridge model.We simulated active stretches of a sarcomere consisting of 2 non-uniform half-sarcomeres on the descending limb of the force-length relationship.Results:The mechanosensing model predicts that,in a passive sarcomere on the descending limb of the force-length relationship,the longer half-sarcomere has a higher fraction of myosin motors in the on-state than the shorter half-sarcomere.The difference in the number of myosin motors in the on-state ensures that upon calcium-mediated thin filament activation,the force-dependent thick filament activation keeps differences in active force within 20%during an active stretch.In the classical cross-bridge model,the corresponding difference exceeds 80%,leading to great length instabilities.Conclusion:Our simulations suggest that,in contrast to the classical cross-bridge model,the mechanosensing regulation is able to stabilize a system of non-uniform half-sarcomeres arranged in series on the descending limb of the force-length relationship.
基金supported by Henan Provincial Key Technologies R&D Program(Grant No.25202310242)Henan Provincial Medical Science and Technology Tackling Program(Grant No.LHGJ20240150).
文摘Hypertrophic cardiomyopathy(HCM)is a major contributor to cardiovascular diseases(CVD),the leading cause of death globally.HCM can precipitate heart failure(HF)by causing the cardiac tissue to weaken and stretch,thereby impairing its pumping efficiency.Moreover,HCM increases the risk of atrial fibrillation,which in turn elevates the likelihood of thrombus formation and stroke.Given these significant clinical ramifications,research into the etiology and pathogenesis of HCM is intensifying at multiple levels.In this review,we discuss and synthesize the latest findings on HCM pathogenesis,drawing on key experimental studies conducted both in vitro and in vivo.We also offer our insights and perspectives on these mechanisms,while highlighting the limitations of current research.Advancing fundamental research in this area is essential for developing effective therapeutic interventions and enhancing the clinical management of HCM.
文摘Sarcomerogenesis,the addition of serial sarcomeres in skeletal muscle myofibrils and fibres,is a natural occurrence during growth and maturation of animals,including humans.However,the detailed mechanisms that allow for sarcomerogenesis are not fully understood.In some diseases,such as cerebral palsy in children,sarcomerogenesis appears to be inhibited or at least reduced,1,2 often causing severe restrictions in muscle and joint function.
基金the National Key Research Program of China(2016YFD0401501).
文摘The effects of xanthan gum (0 % and 0.3 %) on the quality of low sodium (2.0 %, 2.4 %, 2.8 %, 3.2 %, 3.6 % and 4.0 %) salted beef and property of myofibril proteins (MP) extracted from salted beef were researched. Changes in the salting absorptivity, cooking loss, shear force, color and sensory analysis showed that xanthan gum had a positive effect on the quality of salted beef with low salinity (2.0 %, 2.4 % and 2.8 %). MP of salted beef treated with xanthan gum had higher solubility, lower hydrogen bond than that without it (P < 0.05). The decrease of surface hydrophobicity and intrinsic fluorescence intensity indicated that the chromophore of protein was brought into a hydrophobic environment in the presence of xanthan gum. The electrophoresis showed that xanthan gum could improve the concentration of myosin heavy chain, paramyosin and actin after tumble-salting. The data suggested that salted beef and its MP treated with xanthan gum and 2.8 % salt (XS3) had the best properties. Together, xanthan gum could be considered as a sodium salt substitute for the development of low sodium meat products.
文摘Changes in tissue structure, rheological property and water content of dry abalone meat in the process of water restora- tion were studied. The weight and volume of dry abalone meat increased with water restoration. When observed under a light micro- scope, structural change in myofibrils was obvious and a distinct network was found. When water restoration time increased from 24 h to 72 h, the instantaneous modulus E0 and viscosity η1 increased, whereas the rupture strength and relaxation time (τ1) were re- duced. There were no significant changes of rheological parameters (E0, η1, τ1, rupture strength) from 72 h to 96 h of water restoration. Therefore, the dry abalone meat was swollen enough at the time of 72 h. The rheological parameters were obviously influenced by the structural changes.
基金funded by the National Agricultural Science and Technology Innovation Program in China
文摘This study aimed to examine changes in phosphorylation of sarcoplasmic and myofibrillar proteins from longissimus lumborum,semitendinosus,and psoas major muscles during postmortem ageing for 5 d.These sarcoplasmic and myofibrillar proteins were separated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and stained with phosphorous and protein specific stains.Myofibril fragmentation index,pH,the content of lactic acid and the relative activity of μ-calpain in three ovine muscles were measured.These results showed that the relative phosphorylation level of sarcoplasmic and myofibrillar proteins of psoas major muscle were lower compared with longissimus lumborum and semitendinosus muscles(P<0.05).The pH of psoas major muscle was the lowest at 0.5 h postmortem,and the highest after 12 h postmortem(P<0.05).In addition,the relative activity of μ-calpain was higher within 5 d postmortem and myofibril fragmentation index was higher after 1 d postmortem in psoas major muscle than those of longissimus lumborum and semitendinosus muscles(P<0.05).The sarcoplasmic protein phosphorylation may regulate the rate of pH decline to influence the μ-calpain activity and then proteolysis of proteins consequently.This study gives a new perspective of the mechanism of postmortem meat tenderization.
文摘The quantitative correlation between rheological properties and structural characteristic values of chilled abalone meat was studied. Structural changes were observed, and these values were enumerated using image processing and analysis technique. Structural changes in the myofibrils and collagen fibrils were the greatest in chilling for 24 h. After chilling for 48h, similar structures of vertical and cross sections were observed. For chilling from 0h to 72h, the instantaneous modulus E0 of the both section meat decreases gradually with time, but no significant differences were observed after chilling for 48h. The relaxation time and viscosity of both sections attained the same values for the same chilling time, but increased gradually with increasing chilling time. Meanwhile, a negative correlation between the structural characteristic values (Dm, Am, Rvm), and rheological properties (E1, τ1 , η1) clearly exists. Some logarithmic expressions have been obtained for these negative correlations. These results suggest that the difference in rheological properties between the cross and vertical sections was mainly due to the structural changes of myofibrils and collagen fibrils, and rheological properties are influenced quantitatively by the structural characteristic values for chilling from 0h to 72h.
基金supported by the National Natural Science Foundation of China(award No.32372397)the China Agriculture Research System of MOF and MARA(CARS-45)The Figs.5(G)and Fig.7(D)were created with icons provided by Biorender(https://biorender.com)(Agreement number:MY2617L6ID,YG2617LFWE).
文摘The degradation of structural proteins during fish postmortem storage is a critical factor affecting meat quality,leading to economic losses in the seafood industry.The complex interplay between caspase-3 and structural protein stability during fish postmortem storage remains largely unexplored.By treating grass carp fillets with a caspase-3 inhibitor,we establish a model for inhibiting apoptosis,delineating the role of caspase-3 in protein degradation.The effect of caspase-3 on grass carp proteins following postmortem storage and its cascade interaction with calpain and cathepsin L was further investigated.The result demonstrated that the destabili-zation of the mitochondrial membrane during apoptosis led to modifications in the B-cell lymphoma(Bcl)family proteins,subsequently triggered the activation of caspase-9/caspase-3.Additionally,caspase-3 reduced the expression of the calpastatin and lysosomal membrane protein 1(LAMP-1)gene,resulting in increased calpain and cathepsin L activity.SDS-PAGE and liquid chromatography-tandem mass spectrometry(LC-MS/MS)analysis indicated that caspase-3 inhibitor treatment reduced actin fractures and preserved critical structural proteins.This investigation unveils the molecular mechanisms through which caspase-3 affects protein degradation in fish fillets during storage,providing valuable insights into the postmortem degradation processes.
基金supported by the National Key R&D Pro-gram 2021YFD2100103,and“Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province”.
文摘The effects of traditional flame stewing(TFS),commercial pressure cooking(PC),and sous-vide cooking(SVC)on the texture of pork belly and the underlying mechanism were investigated.SVC treatment at a low temper-ature(60℃)achieved weaker oxidation of sulfhydryl groups,lowerα-helical loss,higher surface hydropho-bicity,and actomyosin dissociation,which reduced the shrinkage of myofibrils and loss of immobilized water,thus contributed to a tender meat.However,the protein aggregation predominated without actomyosin disso-ciation during PC treatment,causing the toughening of meat.TFS and PC intensified the atrophy of adipocytes and damage of cell membranes,which helped for the softening of adipose tissue and achieved 13.82%and 17.62%lipid loss,respectively,and contributed to a higher ratio of polyunsaturated fatty acids to saturated fatty acids(0.45-0.46)than SVC(0.34).Comparisons showed that TFS was a more suitable method to prepare cooked pork belly with tender and juicy texture,low lipid content,and high ratio of polyunsaturated fatty acids to saturated fatty acids.This study offered new insights into how cooking regimes affect the texture and lipid-lowering effects of stewed pork.
基金funded by Singapore Ministry of Education Academic Research Fund Tier 1(A-8000469-00-00).
文摘The short shelf-life of shrimp due to microbial activity and protein spoilage poses a threaten for preservation.In this study,the preservation effect of slightly acid electrolysed water(SAEW)combined with grape seed extract(GSE)was investigated.The combined treatment effectively inhibited the growth of spoilage bacteria including Aeromonas,Pseudomonas,Shewanella,and Enterobacteriaceae,which accounted for shrimp spoilage.Besides,the combination efficiently preserved the shrimp colour during storage.To further elucidate the preservative mechanism,the proteomic analysis was conducted,a total of 47 different abundant proteins(DAPs)were identified and quantified.Among these,the combination treatment was most effective in maintaining the main structural proteins presented in myofibrillar protein of shrimp including myosin heavy chain,myosin light chain,actin,and projectin,which was verified by the least changes in texture and protein morphology in combination treated shrimp after storage.These results provided proteomics insight for the preservative mechanism of combined usage of SAEW and GSE.
