Epilepsy is a chronic and severe neurological disorder that has negative effects on the autonomous activities of patients. Functionally, Trem2(triggering receptor expressed on myeloid cells-2) is an immunoglobulin rec...Epilepsy is a chronic and severe neurological disorder that has negative effects on the autonomous activities of patients. Functionally, Trem2(triggering receptor expressed on myeloid cells-2) is an immunoglobulin receptor that affects neurological and psychiatric genetic diseases. Based on this rationale, we aimed to assess the potential role of Trem2 integration with the PI3 K/Akt pathway in epilepsy. We used microarray-based gene expression profiling to identify epilepsy-related differentially-expressed genes. In a mouse hippocampal neuron model of epilepsy, neurons were treated with lowMg^2+ extracellular fluid, and the protein and mRNA expression of Trem2 were determined. Using a gain-offunction approach with Trem2, neuronal apoptosis and its related factors were assessed by flow cytometry, RT-qPCR,and Western blot analysis. In a pilocarpine-induced epileptic mouse model, the malondialdehyde(MDA) and8-hydroxy-20-deoxyguanosine(8-OHdG) content and superoxide dismutase(SOD) and glutathione-peroxidase(GSH-Px) activity in the hippocampus were determined,and the protein expression of Trem2 was measured. In addition, the regulatory effect of Trem2 on the PI3 K/Akt pathway was analyzed by inhibiting this pathway in both the cell and mouse models of epilepsy. Trem2 was found to occupy a core position and was correlated with epilepsy.Trem2 was decreased in the hippocampus of epileptic miceand epileptic hippocampal neurons. Of crucial importance,overexpression of Trem2 activated the PI3 K/Akt pathway to inhibit neuronal apoptosis. Moreover, activation of the PI3 K/Akt pathway through over-expression of Trem2 alleviated oxidative stress, as shown by the increased expression of SOD and GSH-Px and the decreased expression of MDA and 8-OHdG. The current study defines the potential role of Trem2 in inhibiting the development of epilepsy, indicating that Trem2 up-regulation alleviates hippocampal neuronal injury and oxidative stress, and inhibits neuronal apoptosis in epilepsy by activating the PI3 K/Akt pathway.展开更多
BCC-ESM1 is the first version of the Beijing Climate Center’s Earth System Model,and is participating in phase 6 of the Coupled Model Intercomparison Project(CMIP6).The Aerosol Chemistry Model Intercomparison Project...BCC-ESM1 is the first version of the Beijing Climate Center’s Earth System Model,and is participating in phase 6 of the Coupled Model Intercomparison Project(CMIP6).The Aerosol Chemistry Model Intercomparison Project(AerChemMIP)is the only CMIP6-endorsed MIP in which BCC-ESM1 is involved.All AerChemMIP experiments in priority 1 and seven experiments in priorities 2 and 3 have been conducted.The DECK(Diagnostic,Evaluation and Characterization of Klima)and CMIP historical simulations have also been run as the entry card of CMIP6.The AerChemMIP outputs from BCC-ESM1 have been widely used in recent atmospheric chemistry studies.To facilitate the use of the BCC-ESM1 datasets,this study describes the experiment settings and summarizes the model outputs in detail.Preliminary evaluations of BCC-ESM1 are also presented,revealing that:the climate sensitivities of BCC-ESM1 are well within the likely ranges suggested by IPCC AR5;the spatial structures of annual mean surface air temperature and precipitation can be reasonably captured,despite some common precipitation biases as in CMIP5 and CMIP6 models;a spurious cooling bias from the 1960s to 1990s is evident in BCC-ESM1,as in most other ESMs;and the mean states of surface sulfate concentrations can also be reasonably reproduced,as well as their temporal evolution at regional scales.These datasets have been archived on the Earth System Grid Federation(ESGF)node for atmospheric chemistry studies.展开更多
OBJECTIVE： Though the initial etiologies of arthritis are multifactorial, clinically, patients share the prime complaints of the disease, pain. Here the authors assessed the analgesic and anti-inflammatory effects of...OBJECTIVE： Though the initial etiologies of arthritis are multifactorial, clinically, patients share the prime complaints of the disease, pain. Here the authors assessed the analgesic and anti-inflammatory effects of UP1304, a composite that contains a standardized blend of extracts from the rhizome of Curcuma /onga and the root bark of Morus a/ba, on rats with carrageenan-induced paw edema. METHODS： A plant library was screened for bradykinin receptor antagonists./n vivo, the anti- inflammatory and analgesic effects of the standardized composite, UP1304, were evaluated in rats with carrageenan-induced paw edema using oral dose ranges of 100-400 mg/kg. Ibuprofen, at a dose of 200 mg/kg, was used as a reference compound. In vitro, cycleoxygenase （COX） and lipoxygenase （LOX） inhibition assays were performed to evaluate the degree of inflammation. RESULTS： Statistically significant improvements in pain resistance and paw edema suppression were observed in animals treated with UP1304, when compared to vehicle-treated rats. Results from the highest dose of UP1304 （400 mg/kg） were similar to those achieved by ibuprofen treatment at 200 mg/kg. /n vitro, UP1304 showed dose-dependent inhibition of the enzymatic activities of COX and LOX. A half-maximal inhibitory concentration of 9.6 tJg/mL for bradykinin B1 inhibition was calculated for the organic extract of C./onga. Curcumin showed Ki values of 2.73 and 58 IJg/mL for bradykinin receptors B1 and B2, respectively. CONCLUSION： Data presented here suggest that UP1304, analgesic and anti-inflammatory agent of botanical origin, acted as a bradykinin receptor B1 and B2 antagonist, and inhibited COX and LOX enzyme activities. This compound should be considered for the management of symptoms associated with arthritis.展开更多
Salt stress limits plant growth and development.In this study,changes in membrane lipids were investigated in leaves of sorghum seedlings subjected to salt stress(150 mmol L^(-1)NaCl).Galactolipids(DGDG and MGDG)accou...Salt stress limits plant growth and development.In this study,changes in membrane lipids were investigated in leaves of sorghum seedlings subjected to salt stress(150 mmol L^(-1)NaCl).Galactolipids(DGDG and MGDG)accounted for more than 65%of the total glycerolipids in sorghum leaves.The predominance of C36 molecular species in MGDG suggested that sorghum is an 18:3 plant.Under Na Cl treatment,the content of major phospholipids(PC and PE)increased,accompanied by the activation of their metabolism pathways at the transcriptional level.In contrast,the proportion of MGDG and PG dropped drastically,leading to a decreased ratio of plastidic to non-plastidic lipids.An adjustment of glycerolipid pathway between the cytosolic and plastidic compartments was triggered by salt stress,as reflected by the increased conversion of PC to PA,providing precursors for galactolipid synthesis.The elevated DGDG resulted in increased DGDG/MGDG and bilayer/non-bilayer lipid ratios.The double-bond index of PC,PE,and DGDG increased markedly,evidently owing to the increased expression of FAD3 and FAD8.These findings will be helpful for understanding dynamic membrane lipid changes and adaptive lipid remodeling in sorghum response to salt stress.展开更多
The rapid decline of Arctic sea ice has been reminding us the significant impacts caused by global warming.However,the other side of the coin is that this opens a window to utilize the Arctic sea routes in the summer ...The rapid decline of Arctic sea ice has been reminding us the significant impacts caused by global warming.However,the other side of the coin is that this opens a window to utilize the Arctic sea routes in the summer seasons,bringing remarkable economic benefits for ocean transportation between Asia and Europe.However,commercial vessels with low ice classes must tackle substantial environmental challenges in the Arctic sea routes,particularly those caused by variable sea ice,even in the melting seasons.Therefore,the science-based support for shipping safety in the Arctic sea routes is being given more prominence.Emerging satellite remote sensing technology plays a critical role in environmental monitoring in the Arctic.This paper reviews state-of-the-art satellite observations on monitoring sea ice and potential applications on supporting shipping activities in the Arctic Ocean.Moreover,we introduced a recently developed system based on satellite observations to support the safe transportation of Chinese cargo vessels in the Arctic northern sea route,demonstrating the efforts by both the science and business communities to promote the development of the polar silk road.展开更多
Vibrio parahaemolyticus,a predominant seafood-borne pathogen responsible for acute gastroenteritis worldwide,employs sophisticated regulatory networks to adapt to environmental stresses.However,the molecular mechanism...Vibrio parahaemolyticus,a predominant seafood-borne pathogen responsible for acute gastroenteritis worldwide,employs sophisticated regulatory networks to adapt to environmental stresses.However,the molecular mechanisms connecting environmental signals to coordinated regulation of motility,biofilm formation,and virulence effectors expression remain to be elucidated.In this study,we identified vp2835,a gene encoding a putative phosphoesterase of the DHH/DHHA1 family,from a swarming-deficient mutant library.Biochemical studies revealed that Vp2835 could specifically cleave 3′-phosphoadenosine 5′-monophosphate(pAp)into AMP and phosphate.Deletion of vp2835 significantly attenuated both swimming and swarming motility while enhancing biofilm formation.Transmission electron microscopy(TEM)revealed impaired lateral flagellar biosynthesis in the mutant strain when it was cultured on agar surfaces.RNA-seq analysis demonstrated that the deletion of vp2835 triggered differential expression of 1142 genes(|Log_(2)FC|≥1,p<0.05),which was characterized by upregulation of extracellular polysaccharide(EPS)biosynthesis operons(e.g.,cpsA-cpsK and scvD-scvF,Log_(2)FC=1.7-3.7),downregulation of polar/lateral flagellar systems(e.g.,pomAB,flgTOP,flgCEGHJKL,Log_(2)FC=-1.1-3.0;fliN,Log_(2)FC=-2.5),as well as all Type III Secretion System 1(T3SS1)virulence components(Log_(2)FC=-2.8-7.0).Cytotoxicity assays corroborated these findings,showing a 90%reduction in HeLa cell lactate dehydrogenase(LDH)release,which was associated with T3SS1 suppression in the mutant.Collectively,our findings establish vp2835 as a critical regulator of motility and behavioral transitions,biofilm development,and virulence mediated by T3SS1 in V.parahaemolyticus.展开更多
Background: Many studies have emphasized that selective resection of epileptic lesions in temoral lobe is associated with better preservation of cognition function;whether this applies to patients with refractory mesi...Background: Many studies have emphasized that selective resection of epileptic lesions in temoral lobe is associated with better preservation of cognition function;whether this applies to patients with refractory mesial temporal lobe epilepsy (MTLE) remains unknown. The objective of this study was to evaluate changes in cognitive functions, mood status, and quality of life after anterior temporal lobectomy in patients with refractory MTLE. Methods: This single-arm cohort study assessed cognitive function, mood status, and quality of life, as well as electroencephalography findings, in patients with refractory MTLE who underwent anterior temporal lobectomy at Xuanwu Hospital from January 2018 to March 2019. Pre- and post-operative characteristics were compared to evaluate the effects of surgery. Results: Anterior temporal lobectomy significantly reduced the frequencies of epileptiform discharges. The overall success rate of surgery was acceptable. Anterior temporal lobectomy did not result in significant changes in overall cognitive functions (P > 0.05), although changes in certain domains, including visuospatial ability, executive ability, and abstract thinking, were detected. Anterior temporal lobectomy resulted in improvements in anxiety and depression symptoms and quality of life. Conclusions: Anterior temporal lobectomy reduced epileptiform discharges and incidence of post-operative seizures as well as resulted in improved mood status and quality of life without causing significant changes in cognitive function.展开更多
This study aims to explore the key metabolites and metabolic pathways related to the formation of flavor in yak meat,laying the foundation for in-depth analysis of the composition of yak meat and improving meat qualit...This study aims to explore the key metabolites and metabolic pathways related to the formation of flavor in yak meat,laying the foundation for in-depth analysis of the composition of yak meat and improving meat quality.This study selected six healthy 4-year-old male Tianzhu white yaks under the same growth conditions as the research subjects.The metabolites of three groups of longissimi dorsi(LD),triceps brachii(TB),and biceps femoris(BF)were analyzed and identified using gas chromatography-ion mobility spectrometry(GC-IMS),gas chromatography-mass spectrometry(GC-MS),and liquid chromatography-tandem mass spectrometry(LC-MS/MS).The results showed that Tianzhu white yak meat contains abundant metabolites,and the VOC levels in BF muscles are higher than those in LD and TB muscles.The levels of 1-penten-3-one and 2-pentone in LD muscle are higher than in BF and TB muscle.The levels of 2-hexanol,2-hexanol-D,and pyridine in TB muscles are higher than those in LD and BF muscles.The content of benzaldehyde,benzaldehyde D,3-hydroxy-2-butane-D,3-hy-droxy-2-butanone,and mesitylene in BF muscle is higher than in LD and TB muscle.There is a significant dif-ference in the enrichment degree of the glycolysis or gluconeogenesis pathways between LD muscles and the other two groups(BF and TB muscles).There were significant differences in the enrichment degrees of the D-glutamine and D-glutamate metabolic pathways,the alanine,aspartate,and glutamate metabolic pathways be-tween the TB muscles and the other two groups(BF and LD muscles).There is a significant difference in the enrichment degree of the niacin and nicotinamide metabolic pathways between BF and LD muscles.In addition,there were significant differences in the enrichment degree of the histidine metabolism pathway among the three groups of muscles.This study identified key metabolites related to differences in meat quality and flavor for-mation in different parts of the muscle tissue of Tianzhu white yak through metabolomics analysis,providing a theoretical basis for exploring the molecular regulatory mechanism and molecular breeding of yak meat flavor formation in the future,and also providing a reference for quality trait breeding in other beef cattle.展开更多
基金supported by Beijing Key Laboratory of Neuromodulation(BZ0098)the Precision Medicine Project of the Ministry of Science and Technology of China(2016YFC0904400)
文摘Epilepsy is a chronic and severe neurological disorder that has negative effects on the autonomous activities of patients. Functionally, Trem2(triggering receptor expressed on myeloid cells-2) is an immunoglobulin receptor that affects neurological and psychiatric genetic diseases. Based on this rationale, we aimed to assess the potential role of Trem2 integration with the PI3 K/Akt pathway in epilepsy. We used microarray-based gene expression profiling to identify epilepsy-related differentially-expressed genes. In a mouse hippocampal neuron model of epilepsy, neurons were treated with lowMg^2+ extracellular fluid, and the protein and mRNA expression of Trem2 were determined. Using a gain-offunction approach with Trem2, neuronal apoptosis and its related factors were assessed by flow cytometry, RT-qPCR,and Western blot analysis. In a pilocarpine-induced epileptic mouse model, the malondialdehyde(MDA) and8-hydroxy-20-deoxyguanosine(8-OHdG) content and superoxide dismutase(SOD) and glutathione-peroxidase(GSH-Px) activity in the hippocampus were determined,and the protein expression of Trem2 was measured. In addition, the regulatory effect of Trem2 on the PI3 K/Akt pathway was analyzed by inhibiting this pathway in both the cell and mouse models of epilepsy. Trem2 was found to occupy a core position and was correlated with epilepsy.Trem2 was decreased in the hippocampus of epileptic miceand epileptic hippocampal neurons. Of crucial importance,overexpression of Trem2 activated the PI3 K/Akt pathway to inhibit neuronal apoptosis. Moreover, activation of the PI3 K/Akt pathway through over-expression of Trem2 alleviated oxidative stress, as shown by the increased expression of SOD and GSH-Px and the decreased expression of MDA and 8-OHdG. The current study defines the potential role of Trem2 in inhibiting the development of epilepsy, indicating that Trem2 up-regulation alleviates hippocampal neuronal injury and oxidative stress, and inhibits neuronal apoptosis in epilepsy by activating the PI3 K/Akt pathway.
基金supported by the National Key Research and Development Program of China(Grant No.2016YFA0602103)the National Key Research and Development Program of China CERC-WET Project(Grant No.2018YFE0196000)the National Natural Science Foundation of China(Grant No.41805063).
文摘BCC-ESM1 is the first version of the Beijing Climate Center’s Earth System Model,and is participating in phase 6 of the Coupled Model Intercomparison Project(CMIP6).The Aerosol Chemistry Model Intercomparison Project(AerChemMIP)is the only CMIP6-endorsed MIP in which BCC-ESM1 is involved.All AerChemMIP experiments in priority 1 and seven experiments in priorities 2 and 3 have been conducted.The DECK(Diagnostic,Evaluation and Characterization of Klima)and CMIP historical simulations have also been run as the entry card of CMIP6.The AerChemMIP outputs from BCC-ESM1 have been widely used in recent atmospheric chemistry studies.To facilitate the use of the BCC-ESM1 datasets,this study describes the experiment settings and summarizes the model outputs in detail.Preliminary evaluations of BCC-ESM1 are also presented,revealing that:the climate sensitivities of BCC-ESM1 are well within the likely ranges suggested by IPCC AR5;the spatial structures of annual mean surface air temperature and precipitation can be reasonably captured,despite some common precipitation biases as in CMIP5 and CMIP6 models;a spurious cooling bias from the 1960s to 1990s is evident in BCC-ESM1,as in most other ESMs;and the mean states of surface sulfate concentrations can also be reasonably reproduced,as well as their temporal evolution at regional scales.These datasets have been archived on the Earth System Grid Federation(ESGF)node for atmospheric chemistry studies.
文摘OBJECTIVE： Though the initial etiologies of arthritis are multifactorial, clinically, patients share the prime complaints of the disease, pain. Here the authors assessed the analgesic and anti-inflammatory effects of UP1304, a composite that contains a standardized blend of extracts from the rhizome of Curcuma /onga and the root bark of Morus a/ba, on rats with carrageenan-induced paw edema. METHODS： A plant library was screened for bradykinin receptor antagonists./n vivo, the anti- inflammatory and analgesic effects of the standardized composite, UP1304, were evaluated in rats with carrageenan-induced paw edema using oral dose ranges of 100-400 mg/kg. Ibuprofen, at a dose of 200 mg/kg, was used as a reference compound. In vitro, cycleoxygenase （COX） and lipoxygenase （LOX） inhibition assays were performed to evaluate the degree of inflammation. RESULTS： Statistically significant improvements in pain resistance and paw edema suppression were observed in animals treated with UP1304, when compared to vehicle-treated rats. Results from the highest dose of UP1304 （400 mg/kg） were similar to those achieved by ibuprofen treatment at 200 mg/kg. /n vitro, UP1304 showed dose-dependent inhibition of the enzymatic activities of COX and LOX. A half-maximal inhibitory concentration of 9.6 tJg/mL for bradykinin B1 inhibition was calculated for the organic extract of C./onga. Curcumin showed Ki values of 2.73 and 58 IJg/mL for bradykinin receptors B1 and B2, respectively. CONCLUSION： Data presented here suggest that UP1304, analgesic and anti-inflammatory agent of botanical origin, acted as a bradykinin receptor B1 and B2 antagonist, and inhibited COX and LOX enzyme activities. This compound should be considered for the management of symptoms associated with arthritis.
基金supported by the Natural Science Foundation of Heilongjiang Province(ZD2020C007,QC2017024)Heilongjiang Bayi Agricultural University Support Program for San Heng San Zong(ZDZX202101)Special Funds from the Central Finance to Support the Development of Local Universities(TO SXL)。
文摘Salt stress limits plant growth and development.In this study,changes in membrane lipids were investigated in leaves of sorghum seedlings subjected to salt stress(150 mmol L^(-1)NaCl).Galactolipids(DGDG and MGDG)accounted for more than 65%of the total glycerolipids in sorghum leaves.The predominance of C36 molecular species in MGDG suggested that sorghum is an 18:3 plant.Under Na Cl treatment,the content of major phospholipids(PC and PE)increased,accompanied by the activation of their metabolism pathways at the transcriptional level.In contrast,the proportion of MGDG and PG dropped drastically,leading to a decreased ratio of plastidic to non-plastidic lipids.An adjustment of glycerolipid pathway between the cytosolic and plastidic compartments was triggered by salt stress,as reflected by the increased conversion of PC to PA,providing precursors for galactolipid synthesis.The elevated DGDG resulted in increased DGDG/MGDG and bilayer/non-bilayer lipid ratios.The double-bond index of PC,PE,and DGDG increased markedly,evidently owing to the increased expression of FAD3 and FAD8.These findings will be helpful for understanding dynamic membrane lipid changes and adaptive lipid remodeling in sorghum response to salt stress.
基金supported by the National Science Fund for Distinguished Young Scholars(No.42025605).
文摘The rapid decline of Arctic sea ice has been reminding us the significant impacts caused by global warming.However,the other side of the coin is that this opens a window to utilize the Arctic sea routes in the summer seasons,bringing remarkable economic benefits for ocean transportation between Asia and Europe.However,commercial vessels with low ice classes must tackle substantial environmental challenges in the Arctic sea routes,particularly those caused by variable sea ice,even in the melting seasons.Therefore,the science-based support for shipping safety in the Arctic sea routes is being given more prominence.Emerging satellite remote sensing technology plays a critical role in environmental monitoring in the Arctic.This paper reviews state-of-the-art satellite observations on monitoring sea ice and potential applications on supporting shipping activities in the Arctic Ocean.Moreover,we introduced a recently developed system based on satellite observations to support the safe transportation of Chinese cargo vessels in the Arctic northern sea route,demonstrating the efforts by both the science and business communities to promote the development of the polar silk road.
文摘Vibrio parahaemolyticus,a predominant seafood-borne pathogen responsible for acute gastroenteritis worldwide,employs sophisticated regulatory networks to adapt to environmental stresses.However,the molecular mechanisms connecting environmental signals to coordinated regulation of motility,biofilm formation,and virulence effectors expression remain to be elucidated.In this study,we identified vp2835,a gene encoding a putative phosphoesterase of the DHH/DHHA1 family,from a swarming-deficient mutant library.Biochemical studies revealed that Vp2835 could specifically cleave 3′-phosphoadenosine 5′-monophosphate(pAp)into AMP and phosphate.Deletion of vp2835 significantly attenuated both swimming and swarming motility while enhancing biofilm formation.Transmission electron microscopy(TEM)revealed impaired lateral flagellar biosynthesis in the mutant strain when it was cultured on agar surfaces.RNA-seq analysis demonstrated that the deletion of vp2835 triggered differential expression of 1142 genes(|Log_(2)FC|≥1,p<0.05),which was characterized by upregulation of extracellular polysaccharide(EPS)biosynthesis operons(e.g.,cpsA-cpsK and scvD-scvF,Log_(2)FC=1.7-3.7),downregulation of polar/lateral flagellar systems(e.g.,pomAB,flgTOP,flgCEGHJKL,Log_(2)FC=-1.1-3.0;fliN,Log_(2)FC=-2.5),as well as all Type III Secretion System 1(T3SS1)virulence components(Log_(2)FC=-2.8-7.0).Cytotoxicity assays corroborated these findings,showing a 90%reduction in HeLa cell lactate dehydrogenase(LDH)release,which was associated with T3SS1 suppression in the mutant.Collectively,our findings establish vp2835 as a critical regulator of motility and behavioral transitions,biofilm development,and virulence mediated by T3SS1 in V.parahaemolyticus.
文摘Background: Many studies have emphasized that selective resection of epileptic lesions in temoral lobe is associated with better preservation of cognition function;whether this applies to patients with refractory mesial temporal lobe epilepsy (MTLE) remains unknown. The objective of this study was to evaluate changes in cognitive functions, mood status, and quality of life after anterior temporal lobectomy in patients with refractory MTLE. Methods: This single-arm cohort study assessed cognitive function, mood status, and quality of life, as well as electroencephalography findings, in patients with refractory MTLE who underwent anterior temporal lobectomy at Xuanwu Hospital from January 2018 to March 2019. Pre- and post-operative characteristics were compared to evaluate the effects of surgery. Results: Anterior temporal lobectomy significantly reduced the frequencies of epileptiform discharges. The overall success rate of surgery was acceptable. Anterior temporal lobectomy did not result in significant changes in overall cognitive functions (P > 0.05), although changes in certain domains, including visuospatial ability, executive ability, and abstract thinking, were detected. Anterior temporal lobectomy resulted in improvements in anxiety and depression symptoms and quality of life. Conclusions: Anterior temporal lobectomy reduced epileptiform discharges and incidence of post-operative seizures as well as resulted in improved mood status and quality of life without causing significant changes in cognitive function.
基金financially supported by the National Key Research and Development Program of China(2021YFD1600205)China Agri-culture Research System of MOF and MARA(CARS-37)Innovation Project of Chinese Academy of Agricultural Sciences(25-LZIHPS-01).
文摘This study aims to explore the key metabolites and metabolic pathways related to the formation of flavor in yak meat,laying the foundation for in-depth analysis of the composition of yak meat and improving meat quality.This study selected six healthy 4-year-old male Tianzhu white yaks under the same growth conditions as the research subjects.The metabolites of three groups of longissimi dorsi(LD),triceps brachii(TB),and biceps femoris(BF)were analyzed and identified using gas chromatography-ion mobility spectrometry(GC-IMS),gas chromatography-mass spectrometry(GC-MS),and liquid chromatography-tandem mass spectrometry(LC-MS/MS).The results showed that Tianzhu white yak meat contains abundant metabolites,and the VOC levels in BF muscles are higher than those in LD and TB muscles.The levels of 1-penten-3-one and 2-pentone in LD muscle are higher than in BF and TB muscle.The levels of 2-hexanol,2-hexanol-D,and pyridine in TB muscles are higher than those in LD and BF muscles.The content of benzaldehyde,benzaldehyde D,3-hydroxy-2-butane-D,3-hy-droxy-2-butanone,and mesitylene in BF muscle is higher than in LD and TB muscle.There is a significant dif-ference in the enrichment degree of the glycolysis or gluconeogenesis pathways between LD muscles and the other two groups(BF and TB muscles).There were significant differences in the enrichment degrees of the D-glutamine and D-glutamate metabolic pathways,the alanine,aspartate,and glutamate metabolic pathways be-tween the TB muscles and the other two groups(BF and LD muscles).There is a significant difference in the enrichment degree of the niacin and nicotinamide metabolic pathways between BF and LD muscles.In addition,there were significant differences in the enrichment degree of the histidine metabolism pathway among the three groups of muscles.This study identified key metabolites related to differences in meat quality and flavor for-mation in different parts of the muscle tissue of Tianzhu white yak through metabolomics analysis,providing a theoretical basis for exploring the molecular regulatory mechanism and molecular breeding of yak meat flavor formation in the future,and also providing a reference for quality trait breeding in other beef cattle.
