The influence of stationary driven helical current on tearing mode instability in the m=2/n=1 rational surface is explored numerically using resistive magnetohydrodynamic simulation in cylindrical geometry.The results...The influence of stationary driven helical current on tearing mode instability in the m=2/n=1 rational surface is explored numerically using resistive magnetohydrodynamic simulation in cylindrical geometry.The results indicate that the flip instabilities result from the sustained injection of the sufficiently strong helical current driven in the island O-point.The driven helical current induces high order harmonics of instabilities due to the delay of suppressing timing and the increase of its current intensity.With the appropriate current density values,the development of the perturbed kinetic energy can be limited and the occurrence of the flip instabilities can be delayed for a long time.The radial deviation of the current deposition can lead to poor inhibition effect,and the effect of current bias on the boundary is greater than that on the axis.展开更多
Background:Methionine or lysine has been reported to influence DNA methylation and fat metabolism,but their combined effects in N6-methyl-adenosine(m^(6)A)RNA methylation remain unclarified.The combined effects of rum...Background:Methionine or lysine has been reported to influence DNA methylation and fat metabolism,but their combined effects in N6-methyl-adenosine(m^(6)A)RNA methylation remain unclarified.The combined effects of rumen-protected methionine and lysine(RML)in a low-protein(LP)diet on lipid metabolism,m^(6)A RNA methylation,and fatty acid(FA)profiles in the liver and muscle of lambs were investigated.Sixty-three male lambs were divided into three treatment groups,three pens per group and seven lambs per pen.The lambs were fed a 14.5%crude protein(CP)diet(adequate protein[NP]),12.5%CP diet(LP),and a LP diet plus RML(LP+RML)for 60 d.Results:The results showed that the addition of RML in a LP diet tended to lower the concentrations of plasma leptin(P=0.07),triglyceride(P=0.05),and non-esterified FA(P=0.08).Feeding a LP diet increased the enzyme activity or m RNA expression of lipogenic enzymes and decreased lipolytic enzymes compared with the NP diet.This effect was reversed by supplementation of RML with a LP diet.The inclusion of RML in a LP diet affected the polyunsaturated fatty acids(PUFA),n-3 PUFA,and n-6 PUFA in the liver but not in the muscle,which might be linked with altered expression of FA desaturase-1(FADS1)and acetyl-Co A carboxylase(ACC).A LP diet supplemented with RML increased(P<0.05)total m^(6)A levels in the liver and muscle and were accompanied by decreased expression of fat mass and obesity-associated protein(FTO)and alk B homologue 5(ALKBH5).The m RNA expressions of methyltransferase-like 3(METTL3)and methyltransferase-like 14(METTL14)in the LP+RML diet group were lower than those in the other two groups.Supplementation of RML with a LP diet affected only liver YTH domain family(YTHDF2)proteins(P<0.05)and muscle YTHDF3(P=0.09),which can be explained by limited m^(6)Abinding proteins that were mediated in m RNA fate.Conclusions:Our findings showed that the inclusion of RML in a LP diet could alter fat deposition through modulations of lipogenesis and lipolysis in the liver and muscle.These changes in fat metabolism may be associated with the modification of m^(6)A RNA methylation.展开更多
The biological mechanism by which maternal undernutrition increases the metabolic disorder risk of skeletal muscles in offspring is not fully understood.We hypothesize that maternal intake restriction influences metab...The biological mechanism by which maternal undernutrition increases the metabolic disorder risk of skeletal muscles in offspring is not fully understood.We hypothesize that maternal intake restriction influences metabolic signals in the skeletal muscles of offspring via a glucagon-mediated pathway.Twentyfour pregnant goats were assigned to the control group(100%of the nutrients requirement,n=12)and restricted group(60%of the control feed allowance from pregnant days 45 to 100,n=12).Blood and Longissimus thoracis muscle were sampled from dams(100 d of gestation),fetuses(100 d of gestation),and kids(90 d after birth)in each group.The data were analyzed using the linear MIXED model,with the multiple comparison method of SIDAK applied.Intake restriction reduced(P<0.05)the total blood protein of dams and fetuses.Maternal restriction decreased(P<0.05)the cAMP-responsive element-binding protein 1(CREB1),CREB-binding protein(CREBBP),protein kinase A(PKA),aryl hydrocarbon receptor nuclear translocator-like protein 1(BMAL1),protein kinase B(AKT1),mammalian target of rapamycin(mTOR),and regulatory-associated protein of mTOR(RPTOR)mRNA expression in the fetuses,and reduced(P<0.05)the CREBBP,nuclear receptor subfamily 1 group H member 3(NR1 H3),D-box binding PAR bZIP transcription factor(DBP)and PKA mRNA levels in the kids,but increased(P<0.05)the peroxisome proliferator-activated receptor gamma coactivator 1 alpha(PGC1 A)and tuberous sclerosis 2(TSC2)mRNA levels in the fetuses.The mRNA expression of clock circadian regulator(CLOCK)and TSC2 genes was increased(P<0.05)in the restricted kids.The protein expression of total PKA and phosphorylated PKA in the restricted fetuses and kids were downregulated(P<0.05),and the protein expression of total mTOR and phosphorylated mTOR were reduced(P<0.05)in the restricted fetuses and kids.Maternal intake restriction regulated fat oxidation,protein synthesis,and circadian clock expression in the muscles of the offspring probably via the glucagon-mediated PKA-CREB pathway,which reveals a noteworthy molecular pathway that maternal undernutrition leads to metabolic adaptation of skeletal muscle in offspring.展开更多
Enteric methane emission is not only a source of energy loss in ruminants, but also a potent contributor to greenhouse gas production. To identify the nature and timing of interventions to reduce methane emissions req...Enteric methane emission is not only a source of energy loss in ruminants, but also a potent contributor to greenhouse gas production. To identify the nature and timing of interventions to reduce methane emissions requires knowledge of temporal kinetics of methane emissions during animal husbandry.Accordingly, a mathematical model was developed to investigate the pattern of enteric methane emissions after feeding in dairy cows. The model facilitated estimation of total enteric methane emissions（V,g） produced by the residual substrate（V1, g） and newly ingested feed（V2, g）. The model was fitted to the10 h methane emission patterns after morning feeding of 16 non-lactating dairy cows with various body weights（BW）, and the obtained parameters were used to predict the kinetics of 24 h methane emission for each animal. The rate of methane emission（g/h） reached a maximum within 1 to 2 h after feeding,followed by a gradual post-prandial decline to a basal value before the next feeding. The model satisfactorily fitted curves for each cow according to the criterion of goodness-of-fit, and provided biological descriptions for fluctuations in methane emissions based on basal V1 and feeding V2 in response to the changes in BW and dry matter intake（DMI） of different dairy cows. The basal V1 and feeding V2 are probably maintained by slow-and readily-degradable substrates, respectively. The former contributed at least 0.6 of methane production. In summary, the model provides a means to separate basal V1 and feeding V2 within V, and can be used to predict 24 h emission from a single feeding period.展开更多
Manipulation of perinatal diets,such as supplementing feed with rumen-protected glucose(RPG),has been positively regarded as a strategy to improve milking performance.This study was conducted to assess the effects of ...Manipulation of perinatal diets,such as supplementing feed with rumen-protected glucose(RPG),has been positively regarded as a strategy to improve milking performance.This study was conducted to assess the effects of RPG on the fermentation profiles,resident microbiota and mucosal immunity in the cecum.Ten Holstein dairy cows were randomly assigned to either a 25 g/kg RPG diet(DM basis)or a 11 g/kg coating fat diet(control,CON).Compared with the CON group,the acetate-to-propionate ratio was lower in the RPG group.Gene expression analysis indicated that RPG supplementation tended to upregulate the expression of Na^(+)/H^(+)hydrogen exchanger 3(NHE3)(P=0.076).RPG supplementation downregulated the expression of genes involved in self-rehabilitation such as matrix metalloproteinase 1(MMP1),MMP3,MMP9 and MMP13.Additionally,the mRNA expression of genes involved in immunity including Toll-like receptors(TLR4,TLR6 and TLR7)and proinflammatory cytokines(immune interferon gamma[IFNG]and interleukins interleukin 17 A[IL7 F],IL17 A,IL22),was downregulated by RPG supplementation.Nonetheless,no differences existed in the bacterial copy number and beta diversity between the 2 groups.Overall,supplementation with RPG would probably cause a shift towards propionate production in the cecal digesta,and promote the immune homeostasis of the cecal mucosa in transition dairy cows.Our results extended the basic understanding of RPG supplementation and utilization in transition dairy cows in terms of host microbe interplay in the cecum.展开更多
Maternal behaviors and brains change dramatically with pregnancy,parturition and other mothering experiences.However,whether paternal behavior,brain plasticity and levels of relevant hormones also change along with fa...Maternal behaviors and brains change dramatically with pregnancy,parturition and other mothering experiences.However,whether paternal behavior,brain plasticity and levels of relevant hormones also change along with fathering experience and pups’age remains unclear.Using socially monogamous mandarin voles(Micro-tus mandarinus),we found that experienced fathers exhibited more active paternal behaviors,such as licking,retrievals and nest building,but less paternal care,such as huddling,than new fathers.The high levels of licking and nest building appeared in the earlier days of their mate’s lactation.Experienced fathers retrieved 9–13-day-old pups more frequently.However,these paternal behaviors did not show significant changes with age of pups in new fathers.In addition,experienced fathers had dramatically higher prolactin levels than new fathers but had similar concentrations of testosterone to new fathers.New fathers had lower levels of testosterone but higher levels of prolactin than new paired males.The fathers had higher prolactin levels in the earlier days of their mate’s lactation.The new and experienced fathers had similar dendritic length and spine density on pyramidal neurons in the medial prefrontal cortex but displayed higher levels than new paired males.Taken together,these results indicate that reduction of testosterone levels and increase of prolactin levels may be associated with initiation of paternal care.Fathering experience significantly affects levels of parental care and paternal behaviors toward different aged pups,and brain plasticity can also be enhanced by transition to fatherhood.展开更多
基金supported by the National Key R&D Program of China(No.2017YFE0302000)the Natural Science Foundation of Hunan Province(No.2017JJ2230)+1 种基金National Natural Science Foundation of China(Nos.11675073 and11375085)the Key Laboratory of Magnetic Confinement Nuclear Fusion Research in Hengyang(2018KJ108)
文摘The influence of stationary driven helical current on tearing mode instability in the m=2/n=1 rational surface is explored numerically using resistive magnetohydrodynamic simulation in cylindrical geometry.The results indicate that the flip instabilities result from the sustained injection of the sufficiently strong helical current driven in the island O-point.The driven helical current induces high order harmonics of instabilities due to the delay of suppressing timing and the increase of its current intensity.With the appropriate current density values,the development of the perturbed kinetic energy can be limited and the occurrence of the flip instabilities can be delayed for a long time.The radial deviation of the current deposition can lead to poor inhibition effect,and the effect of current bias on the boundary is greater than that on the axis.
基金funded by Chinese Academy of Sciences(Strategic Priority Research Program Grant NO.XDA26040304,XDA26050102)CAS Science and Technology Service Network Initiative(KFJ-STS-ZDTP-075)Innovation Province Project(2019RS3021)。
文摘Background:Methionine or lysine has been reported to influence DNA methylation and fat metabolism,but their combined effects in N6-methyl-adenosine(m^(6)A)RNA methylation remain unclarified.The combined effects of rumen-protected methionine and lysine(RML)in a low-protein(LP)diet on lipid metabolism,m^(6)A RNA methylation,and fatty acid(FA)profiles in the liver and muscle of lambs were investigated.Sixty-three male lambs were divided into three treatment groups,three pens per group and seven lambs per pen.The lambs were fed a 14.5%crude protein(CP)diet(adequate protein[NP]),12.5%CP diet(LP),and a LP diet plus RML(LP+RML)for 60 d.Results:The results showed that the addition of RML in a LP diet tended to lower the concentrations of plasma leptin(P=0.07),triglyceride(P=0.05),and non-esterified FA(P=0.08).Feeding a LP diet increased the enzyme activity or m RNA expression of lipogenic enzymes and decreased lipolytic enzymes compared with the NP diet.This effect was reversed by supplementation of RML with a LP diet.The inclusion of RML in a LP diet affected the polyunsaturated fatty acids(PUFA),n-3 PUFA,and n-6 PUFA in the liver but not in the muscle,which might be linked with altered expression of FA desaturase-1(FADS1)and acetyl-Co A carboxylase(ACC).A LP diet supplemented with RML increased(P<0.05)total m^(6)A levels in the liver and muscle and were accompanied by decreased expression of fat mass and obesity-associated protein(FTO)and alk B homologue 5(ALKBH5).The m RNA expressions of methyltransferase-like 3(METTL3)and methyltransferase-like 14(METTL14)in the LP+RML diet group were lower than those in the other two groups.Supplementation of RML with a LP diet affected only liver YTH domain family(YTHDF2)proteins(P<0.05)and muscle YTHDF3(P=0.09),which can be explained by limited m^(6)Abinding proteins that were mediated in m RNA fate.Conclusions:Our findings showed that the inclusion of RML in a LP diet could alter fat deposition through modulations of lipogenesis and lipolysis in the liver and muscle.These changes in fat metabolism may be associated with the modification of m^(6)A RNA methylation.
基金supported by the National Natural Science Foundation of China[31730092,31760678 and 31402105]Hunan innovative Province construction project[2019RS3021]。
文摘The biological mechanism by which maternal undernutrition increases the metabolic disorder risk of skeletal muscles in offspring is not fully understood.We hypothesize that maternal intake restriction influences metabolic signals in the skeletal muscles of offspring via a glucagon-mediated pathway.Twentyfour pregnant goats were assigned to the control group(100%of the nutrients requirement,n=12)and restricted group(60%of the control feed allowance from pregnant days 45 to 100,n=12).Blood and Longissimus thoracis muscle were sampled from dams(100 d of gestation),fetuses(100 d of gestation),and kids(90 d after birth)in each group.The data were analyzed using the linear MIXED model,with the multiple comparison method of SIDAK applied.Intake restriction reduced(P<0.05)the total blood protein of dams and fetuses.Maternal restriction decreased(P<0.05)the cAMP-responsive element-binding protein 1(CREB1),CREB-binding protein(CREBBP),protein kinase A(PKA),aryl hydrocarbon receptor nuclear translocator-like protein 1(BMAL1),protein kinase B(AKT1),mammalian target of rapamycin(mTOR),and regulatory-associated protein of mTOR(RPTOR)mRNA expression in the fetuses,and reduced(P<0.05)the CREBBP,nuclear receptor subfamily 1 group H member 3(NR1 H3),D-box binding PAR bZIP transcription factor(DBP)and PKA mRNA levels in the kids,but increased(P<0.05)the peroxisome proliferator-activated receptor gamma coactivator 1 alpha(PGC1 A)and tuberous sclerosis 2(TSC2)mRNA levels in the fetuses.The mRNA expression of clock circadian regulator(CLOCK)and TSC2 genes was increased(P<0.05)in the restricted kids.The protein expression of total PKA and phosphorylated PKA in the restricted fetuses and kids were downregulated(P<0.05),and the protein expression of total mTOR and phosphorylated mTOR were reduced(P<0.05)in the restricted fetuses and kids.Maternal intake restriction regulated fat oxidation,protein synthesis,and circadian clock expression in the muscles of the offspring probably via the glucagon-mediated PKA-CREB pathway,which reveals a noteworthy molecular pathway that maternal undernutrition leads to metabolic adaptation of skeletal muscle in offspring.
基金“Strategic Priority Research ProgramClimate Change:Carbon Budget and Relevant Issues”(Grant No.XDA05020700)the National Natural Science Foundation of China(Grant No.31472133,31561143009 and 31320103917)International Atomic Energy Agency(Grant No.16315)for the joint financial supports
文摘Enteric methane emission is not only a source of energy loss in ruminants, but also a potent contributor to greenhouse gas production. To identify the nature and timing of interventions to reduce methane emissions requires knowledge of temporal kinetics of methane emissions during animal husbandry.Accordingly, a mathematical model was developed to investigate the pattern of enteric methane emissions after feeding in dairy cows. The model facilitated estimation of total enteric methane emissions（V,g） produced by the residual substrate（V1, g） and newly ingested feed（V2, g）. The model was fitted to the10 h methane emission patterns after morning feeding of 16 non-lactating dairy cows with various body weights（BW）, and the obtained parameters were used to predict the kinetics of 24 h methane emission for each animal. The rate of methane emission（g/h） reached a maximum within 1 to 2 h after feeding,followed by a gradual post-prandial decline to a basal value before the next feeding. The model satisfactorily fitted curves for each cow according to the criterion of goodness-of-fit, and provided biological descriptions for fluctuations in methane emissions based on basal V1 and feeding V2 in response to the changes in BW and dry matter intake（DMI） of different dairy cows. The basal V1 and feeding V2 are probably maintained by slow-and readily-degradable substrates, respectively. The former contributed at least 0.6 of methane production. In summary, the model provides a means to separate basal V1 and feeding V2 within V, and can be used to predict 24 h emission from a single feeding period.
基金supported by the National Key Research and Development Program of China(grant no.2016YFD0501206 and 2018YFD0501604)the Major Project for Science and Technology of Hunan Province(grants no.2017NK1020)+1 种基金the CAS Pioneer Hundred Talents Program and Youth Innovation Team Project of ISA,CAS(2017QNCXTDZCS)the CAS Science and Technology Service Network Initiative(KFJ-STS-ZDTP-056)。
文摘Manipulation of perinatal diets,such as supplementing feed with rumen-protected glucose(RPG),has been positively regarded as a strategy to improve milking performance.This study was conducted to assess the effects of RPG on the fermentation profiles,resident microbiota and mucosal immunity in the cecum.Ten Holstein dairy cows were randomly assigned to either a 25 g/kg RPG diet(DM basis)or a 11 g/kg coating fat diet(control,CON).Compared with the CON group,the acetate-to-propionate ratio was lower in the RPG group.Gene expression analysis indicated that RPG supplementation tended to upregulate the expression of Na^(+)/H^(+)hydrogen exchanger 3(NHE3)(P=0.076).RPG supplementation downregulated the expression of genes involved in self-rehabilitation such as matrix metalloproteinase 1(MMP1),MMP3,MMP9 and MMP13.Additionally,the mRNA expression of genes involved in immunity including Toll-like receptors(TLR4,TLR6 and TLR7)and proinflammatory cytokines(immune interferon gamma[IFNG]and interleukins interleukin 17 A[IL7 F],IL17 A,IL22),was downregulated by RPG supplementation.Nonetheless,no differences existed in the bacterial copy number and beta diversity between the 2 groups.Overall,supplementation with RPG would probably cause a shift towards propionate production in the cecal digesta,and promote the immune homeostasis of the cecal mucosa in transition dairy cows.Our results extended the basic understanding of RPG supplementation and utilization in transition dairy cows in terms of host microbe interplay in the cecum.
基金This research was supported by the National Natural Science Foundation of China(31372213 and 31670421)Fundamental Research Funds for Central University(GK201305009)Xi’an Science Technology Program(CXY1531WL17).
文摘Maternal behaviors and brains change dramatically with pregnancy,parturition and other mothering experiences.However,whether paternal behavior,brain plasticity and levels of relevant hormones also change along with fathering experience and pups’age remains unclear.Using socially monogamous mandarin voles(Micro-tus mandarinus),we found that experienced fathers exhibited more active paternal behaviors,such as licking,retrievals and nest building,but less paternal care,such as huddling,than new fathers.The high levels of licking and nest building appeared in the earlier days of their mate’s lactation.Experienced fathers retrieved 9–13-day-old pups more frequently.However,these paternal behaviors did not show significant changes with age of pups in new fathers.In addition,experienced fathers had dramatically higher prolactin levels than new fathers but had similar concentrations of testosterone to new fathers.New fathers had lower levels of testosterone but higher levels of prolactin than new paired males.The fathers had higher prolactin levels in the earlier days of their mate’s lactation.The new and experienced fathers had similar dendritic length and spine density on pyramidal neurons in the medial prefrontal cortex but displayed higher levels than new paired males.Taken together,these results indicate that reduction of testosterone levels and increase of prolactin levels may be associated with initiation of paternal care.Fathering experience significantly affects levels of parental care and paternal behaviors toward different aged pups,and brain plasticity can also be enhanced by transition to fatherhood.
