Isolated Star Formation A Compact HII Region in the Virgo Cluster

海岛棉DELLA蛋⽩编码基因GbGAI的克隆与功能初步分析0引⾔海岛棉（长绒棉）（Gossiypium barbadense L.）的纤维具有长、细、强等突出特点，在棉花栽培种中品质最优。

长绒棉⽣产对于提⾼中国纺织产品档次、增强⾏业竞争⼒发挥了重要作⽤[1]。

20世纪90年代以后，中国选育出了纤维品质性状相对优异的海岛棉新品种，如新海l3号、新海l5号、新海l7号等。

这些品种的主要纤维物理指标，已经能够与世界上品质最优的超级长绒棉品种相媲美，只是麦克隆值偏⼤，对纺优质⾼档纱来说纤维较粗。

因此，中国选育的长绒棉品种的综合品质性状尚需进⼀步改良[2]。

⾚霉素（gibberellin ，GAs ）是⼀类重要的植物激基⾦项⽬：国家⾃然科学基⾦（307600991）；兵团博⼠资⾦（2007JC08）；⽯河⼦⼤学博⼠基⾦（RCZ200620）。

第⼀作者简介：曲廷云，男，1984年出⽣，⼭东德州⼈，在读硕⼠⽣，主要从事植物基因⼯程研究。

E-mail ：qty1385@/doc/b62940039.html。

通讯作者：郑银英，⼥，1975年出⽣，硕⼠⽣导师，博⼠，从事植物⽣理⽣化与分⼦⽣物学研究。

通信地址：832003新疆⽯河⼦市北四路⽯河⼦⼤学农业⽣物技术重点实验室，E-mail ：zhengyinying@/doc/b62940039.html。

收稿⽇期：2010-02-04，修回⽇期：2010-03-08。

海岛棉DELLA 蛋⽩编码基因GbGAI 的克隆与功能初步分析曲廷云1，王拴锁2，彭明1,3，崔百明1，郑银英1（1⽯河⼦⼤学农业⽣物技术重点实验室⁄⽯河⼦⼤学⽣命科学院，新疆⽯河⼦832003；2中国科学院遗传与发育⽣物学研究所植物细胞与染⾊体⼯程国家重点实验室，北京100101；3中国热带农业科学院热带⽣物技术研究所，海⼝571101）摘要：⾚霉素在棉花纤维发育过程中起着重要作⽤。

DELLA 蛋⽩是⾚霉素信号传导通路中的⼀类重要负调节因⼦。

ARTICLEOPENReceived8Apr2015|Accepted25Aug2015|Published29Sep2015Entropy-stabilized oxidesChristina M.Rost1,Edward Sachet1,Trent Borman1,Ali Moballegh1,Elizabeth C.Dickey1,Dong Hou1,Jacob L.Jones1,Stefano Curtarolo2&Jon-Paul Maria1Configurational disorder can be compositionally engineered into mixed oxide by populating asingle sublattice with many distinct cations.The formulations promote novel and entropy-stabilized forms of crystalline matter where metal cations are incorporated in new ways.Here,through rigorous experiments,a simple thermodynamic model,and afive-componentoxide formulation,we demonstrate beyond reasonable doubt that entropy predominatesthe thermodynamic landscape,and drives a reversible solid-state transformation betweena multiphase and single-phase state.In the latter,cation distributions are proven tobe random and homogeneous.Thefindings validate the hypothesis that deliberateconfigurational disorder provides an orthogonal strategy to imagine and discover new phasesof crystalline matter and untapped opportunities for property engineering.1Department of Materials Science and Engineering,North Carolina State University,Raleigh,North Carolina27695,USA.2Department of Mechanical Engineering and Materials Science,Center for Materials Genomics,Duke University,Durham,North Carolina27708,USA.Correspondence and requests for materials should be addressed to J.-P.M.(email:jpmaria@)or to S.C.(email:stefano@).A grand challenge facing materials science is the continuoushunt for advanced materials with properties that satisfythe demands of rapidly evolving technology needs.The materials research community has been addressing this problem since the early1900s when Goldschmidt reported the‘the method of chemical substitution’1that combined a tabulation of cationic and anionic radii with geometric principles of ion packing and ion radius ratios.Despite its simplicity,this model enabled a surprising capability to predict stable phases and structures.As early as1926many of the technologically important materials that remain subjects of contemporary research were identified (though their properties were not known);BaTiO3,AlN,GaP, ZnO and GaAs are among that list.These methods are based on overarching natural tendencies for binary,ternary and quaternary structures to minimize polyhedral distortions,maximize spacefilling and adopt polyhedral linkages that preserve electroneutrality1–3.The structure-field maps compiled by Muller and Roy catalogue the crystallographic diversity in the context of these largely geometry-based predictions4.There are,however,limitations to the predictive power,particularly when factors like partial covalency and heterodesmic bonding are considered.To further expand the library of advanced materials and property opportunities,our community explores possibilities based on mechanical strain5,artificial layering6,external fields7,combinatorial screening8,interface engineering9,10and structuring at the nanoscale6,11.In many of these efforts, computation and experiment are important companions.Most recently,high-throughput methods emerged as a power-ful engine to assess huge sections of composition space12–17and identified rapidly new Heusler alloys,extensive ion substitution schemes18,19,new18-electron ABX compounds20and new ferroic semiconductors21.While these methods offer tremendous predictive power and an assessment of composition space intractable to experiment, they often utilize density functional theory calculations conducted at0K.Consequently,the predicted stabilities are based on enthalpies of formation.As such,there remains a potential section of discovery space at elevated temperatures where entropy predominates the free-energy landscape.This landscape was explored recently by incorporating deliberatelyfive or more elemental species into a single lattice with random occupancy.In such crystals,entropic contributions to the free energy,rather than the cohesive energy, promote thermodynamic stability atfinite temperatures.The approach is being explored within the high-entropy-alloy family of materials(HEAs)22,in which extremely attractive properties continue to be found23,24.In HEAs,however,discussion remains regarding the true role of configurational entropy25–28, as samples often contain second phases,and there are uncertainties regarding short-range order.In response to these open discussions,HEAs have been referred to recently as multiple-principle-element alloys29.It is compelling to consider similar phenomena in non-metallic systems,particularly considering existing information from entropy studies in mixed oxides.In1967Navrotsky and Kleppa showed how configurational entropy regulates the normal-to-inverse transformation in spinels,where cations transition between ordered and disordered site occupancy among the available sublattices30,31.These fundamental thermodynamic studies lead one to hypothesize that in principle,sufficient temperature would promote an additional transition to a structure containing only one sublattice with random cation occupancy.From experiment we know that before such transitions,normal materials melt,however,it is conceivable that synthetic formulations exist,which exhibit them.Inspired by research activities in the metal alloy communities and fundamental principles of thermodynamics we extend the entropy concept tofive-component oxides.With unambiguous experiments we demonstrate the existence of a new class of mixed oxides that not only contains high configurational entropy but also is indeed truly entropy stabilized.In addition,we present a hypothesis suggesting that entropy stabilization is particularly effective in a compound with ionic character.ResultsChoosing an appropriate experimental candidate.The candi-date system is an equimolar mixture of MgO,CoO,NiO,CuO and ZnO,(which we label as‘E1’)so chosen to provide the appropriate diversity in structures,coordination and cationic radii to test directly the entropic ansatz.The rationale for selection is as fol-lows:the ensemble of binary oxides should not exhibit uniform crystal structure,electronegativity or cation coordination,and there should exist pairs,for example,MgO–ZnO and CuO–NiO, that do not exhibit extensive solubility.Furthermore,the entire collection should be isovalent such that relative cation ratios can be varied continuously with electroneutrality preserved at the net cation to anion ration of unity.Tabulated reference data for each component,including structure and ionic radius,can be found in Supplementary Table1.Testing reversibility.In thefirst experiment,ceramic pellets of E1are equilibrated in an air furnace and quenched to room temperature.The temperature spanned a range from700to 1,100°C,in50-°C increments.X-ray diffraction patterns showing the phase evolution are depicted in Fig.1.After700°C,two prominent phases are observed,rocksalt and tenorite.The tenorite phase fraction reduces with increasing equilibration temperature.Full conversion to single-phase rocksalt occurs between850and900°C,after which there are no additional peaks,the background is low andflat,and peak widths are narrow in two-theta(2y)space.Reversibility is a requirement of entropy-driven transitions. Consequently,low-temperature equilibration should transform homogeneous1,000°C-equilibrated E1back to its multiphase state(and vice versa on heating).Figure1also shows a sequence of X-ray diffraction patterns for such a thermal excursion;initial equilibration at1,000°C,a second anneal at750°C,andfinally a return to1,000°C.The transformation from single phase,to multiphase,to single phase is evident by the X-ray patterns and demonstrates an enantiotropic(that is,reversible with tempera-ture32)phase transition.Testing entropy though composition variation.A composition experiment is conducted to further characterize this phase tran-sition to the random solid solution state.If the driving force is entropy,altering the relative cation ratios will influence the transition temperature.Any deviation from equimolarity will reduce the number of possible configurations O(S c¼k B log(O)), thus increasing the transition temperature.Because S c(x i)is logarithmically linked to mole fraction via B x i log(x i),the com-positional dependence is substantial.This dependency underpins our gedankenexperiment where the role of entropy can be tested by measuring the dependency of transition temperature as a function of the total number of components present,and of the composition of a single component about the equimolar formulation.The calculated entropy trends for an ideal mixture are illustrated in Fig.2b,which plots configurational entropy for a set of mixtures having N species where the composition of an individual species is changed and the others(NÀ1)are keptequimolar.Two dependencies become apparent:the entropy increases as new species are added and the maximum entropy is achieved when all the species have the same fraction.Both dependencies assume ideal random mixing.Two series of composition-varying experiments investigate the existence of these trends in formulation E1.The first experiment monitors phase evolution in five compounds,each related to the parent E1by the extraction of a single component.The sets are equilibrated at 875°C (the threshold temperature for complete solubility)for 12h.The diffraction patterns in Fig.2a show that removing any component oxide results in material with multiple phases.A four-species set equilibrated under these conditions never yields a single-phase material.The second experiment uses five individual phase diagrams to explore the configurational entropy versus composition trend.In each,the composition of a single component is varied by ±2,±6and ±10%increments about the equimolar composition while the others are kept even.Since any departure from equimolarity reduces the configurational entropy,it should increase transition temperatures to single phase,if thattransitionI n t e n s i t y2030405060702 (°)801.81,100N =5No ZnONo MgON =4No CuON =3No NiONo CoON =21,0501,000950T e m p e r a t u r e (°C )T e m p e r a t u r e (°C )T e m p e r a t u r e (°C )T e m p e r a t u r e (°C )T e m p e r a t u r e (°C )S /k B9008501,1001,0501,0009509008501,1001,0501,0009509008501,1001,0501,0009509008501,1001,0501,0009509008500.0X NX NiOX CuOX ZnOX MgoX CoO0.5 1.00.10.20.30.10.20.30.10.20.30.10.20.30.10.20.31.62223112202001111.41.21.00.80.60.40.20.0J14**********Figure 2|Compositional analysis.(a )X-ray diffraction analysis for a composition series where individual components are removed from the parent composition E1and heat treated to the conditions that would otherwise produce full solid solution.Asterisks identify peaks from rocksalt while carrots identify peaks from other crystal structures.(b )Calculated configurational entropy in an N -component solid solutions as a function of mol%of the N th component,and (c –g )partial phase diagrams showing the transition temperature to single phase as a function of composition (solvus )in the vicinity of the equimolar composition where maximum configurational entropy is expected.Error bars account for uncertainty between temperature intervals.Each phase diagram varies systematically the concentration of one element.L o g i n t e n s i t y750 °C750 °C800 °C850 °C900 °C1,000 °C2001111,000 °C 2 (°)T (200)T (002)T (110)T (200)T (002)T (110)Figure 1|X-ray diffraction patterns for entropy-stabilized oxide formulation E1.E1consists of an equimolar mixture of MgO,NiO,ZnO,CuO and CoO.The patterns were collected from a single pellet.The pellet was equilibrated for 2h at each temperature in air,then air quenched to room temperature by direct extraction from the furnace.X-ray intensity is plotted on a logarthimic scale and arrows indicate peaks associated with non-rocksalt phases,peaks indexed with (T)and with (RS)correspond to tenorite and rocksalt phases,respectively.The two X-ray patterns for 1,000°C annealed samples are offset in 2y for clarity.is in fact entropy driven.The specific formulations used are given in Supplementary Table 2.Figure 2c–g are phase diagrams of composition versus transformation temperature for the five sample sets that varied mole fraction of a single component.The diagrams were produced by equilibrating and quenching individual samples in 25°C intervals between 825and 1,125°C to obtain the T trans -composition solvus .In all cases equimolarity always leads to the lowest transformation temperatures.This is in agreement with entropic promotion,and consistent with the ideal model shown in Fig.2b.One set of raw X-ray patterns used to identify T trans for 10%MgO is given as an example in Supplementary Fig.1.Testing endothermicity .Reversibility and compositionally dependent solvus lines indicate an entropy-driven process.As such,the excursion from polyphase to single phase should be endothermic.An entropy-driven solid–solid transformation is similar to melting,thus requires heat from an external source 33.To test this possibility,the phase transformation in formulation E1can be co-analysed with differential scanning calorimetry and in situ temperature-dependent X-ray diffraction using identical heating rates.The data for both measurements are shown in Fig.3.Figure 3a is a map of diffracted intensity versus diffraction angle (abscissa)as a function of temperature.It covers B 4°of 2y space centred about the 111reflection for E1.At a temperature interval between 825and 875°C,there is a distinct transition to single-phase rocksalt structure—all diffraction events in that range collapse into an intense o 1114rocksalt peak.Figure 3b contains the companion calorimetric result where one finds a pronounced endotherm in the identical temperature window.The endothermic response only occurs when the system adds heat to the sample,uniquely consistent with an entropy-driven transformation 33.We note the small mass loss (B 1.5%)at the endothermic transition.This mass loss results from the conversion of some spinel (an intermediate phase seen by X-ray diffraction)to rocksalt,which requires reduction of 3þto 2þcations and release of oxygen to maintain stoichiometry.To address concerns regarding CuO reduction,Supplementary Fig.2shows a differential scanning calorimetry and thermal gravimetric analysis curve for pure CuO collected under the same conditions.There is no oxygen loss in the vicinity of 875°C.Testing homogeneity .All experimental results shown so far support the entropic stabilization hypothesis.However,all assume that homogeneous cation mixing occurs above the tran-sition temperature.It is conceivable that local composition fluc-tuations produce coherent clustering or phase separation events that are difficult to discern by diffraction using a laboratory sealed tube diffractometer.The solvus lines of Fig.2c–g support random mixing,as the most stable composition is equimolar (a condition only expected for ideal/regular solutions),but it is appropriate to ensure self-consistency with direct measurements.To characterize the cation distributions,extended X-ray absorption fine structure (EXAFS)and scanning transmission electron microscopy with energy dispersive X-ray spectroscopy (STEM EDS)is used to analyse structure and chemistry on the local scale.EXAFS data were collected for Zn,Ni,Cu and Co at the Advanced Photon Source 12-BM-B 34,35.The fitted data are shown in Fig.4,the raw data are given in Supplementary Fig.3.The fitted data for each element provide two conclusions:the cation-to-anion first-near-neighbour distances are identical (within experimental error of ±0.01Å)and the local structures for each element to approximately seven near-neighbour distances are similar.Both observations are only consistent with a random cation distribution.As a corroborating measure of local homogeneity,chemical analysis was conducted using a probe-corrected FEI Titan STEM with EDS detection.Thin film samples of E1,prepared by pulsed laser deposition,are the most suitable samples to make the assessment.Details of preparation are given in the methods,and X-ray and electron diffraction analysis for the film are provided in Supplementary Figs 4and 5.The sample was thinned by mechanical polishing and ion milling.Figure 5shows a collection of images including Fig.5a,the high-angle annular dark-field signal (HAADF).In Fig.5b–f,the EDS signals for the K a emission energies of Mg,Co,Ni,Cu and Zn are shown (additional lower magnification images are included in Supplementary Fig.6).All magnifications reveal chemically and structurally homogeneous material.1,100R 111R 111Mass change (%)510151,000900800700600500400300200DSC –30–20Endo DSC (mW) Exo35.536.537.52θ (°)–10010Mass100T e m p e r a t u r e (°C )T e m p e r a t u r e (°C )Figure 3|Demonstrating endothermicity.(a )In situ X-ray diffraction intensity map as a function of 2y and temperature;and (b )differential scanning calorimetry trace for formulation ‘E1’.Note that the conversion to single phase is accompanied by an endotherm.Both experiments were conducted at a heating rate of 5°C min À1.04k (Å–1)(k )×k 2 (Å–2)2ZnNiCuCo681012Figure 4|Extended X-ray absorption fine structure.EXAFS measured at Advanced Photon Source beamlime 12-BM after energy normalization and fitting.Note that the oscillations for each element occur with similar relative intensity and at similar reciprocal spacing.This suggests a similar local structural and chemical environment for each.X-ray diffraction,EXAFS and STEM–EDS probes are sensitive to 10s of nm,10s of Åand 1Ålength scales,respectively.While any single technique could be misinterpreted to conclude homogenous mixing,the combination of X-ray diffraction,EXAFS and STEM–EDS provide very strong evidence.We note,in particular,the similarity in EXAFS oscillations (both in amplitude and position)out to 12inverse angstroms.This similarly would be lost if local ordering or clustering were present.Consequently,we conclude with certainty that the cations are uniformly dispersed.DiscussionThe set of experimental outcomes show that the transition from multiple-phase to single phase in E1is driven by configurational entropy.To complete our thermodynamic understanding of this system,it is important to understand and appreciate the enthalpic penalties that establish the transition temperature.In so doing,the data set can be tested for self-consistency,and the present data are brought into the context of prior research on oxide solubility.First,we consider an equation relating the initial and final states of the proposed phase transition:MgO ðRS ÞþNiO ðRS ÞþCoO ðRS ÞþCuO ðT ÞþZnO ðW Þ¼Mg ;Ni ;Co ;Cu ;Zn ðÞO ðRS ÞFor MgO,NiO and CoO,the crystal structures of the initial and final states are identical.If we assume that solution of each into the E1rocksalt phase is ideal,the enthalpy for mixing is zero.For CuO and ZnO,there must be a structural transition to rocksalt on dissolution from tenorite and wurtzite,respectively.If we again assume (for simplicity)that the solution is ideal,the mixing energy is zero,but there is an enthalpic penalty associated with the structure transition.From Davies et al.and Bularzik et al.,we know the reference chemical potential changes for the wurtzite-to-rocksalt and the tenorite-to-rocksalt transitions of ZnO and CuO;they are 25and 22kJ mol À1,respectively 36,37.If we make the assumption that the transition enthalpies of ZnO(wurtzite)to ZnO(rocksalt E1)and CuO(tenorite)to CuO(rocksalt E1)are comparable,then the enthalpic penalty for solution into E1can be estimated.For ZnO and CuO,the transition to solid solution in a rocksalt structure involves an enthalpy change of (0.2)Á(25kJ mol À1)þ(0.2)Á(22kJ mol À1),a total of þ10kJ mol À1.This calculation is based on the productof the mol fraction of each multiplied by the reference transition enthalpy.This assumption is consistent with the report of Davies et al.who showed that the chemical potential of a particular cation in a particular structure is associated with the molar volume of that structure 36.Since the rocksalt phases of ZnO and CuO have molar volumes comparable to E1,their reference transition enthalpy values are considered suitable proxies.In comparison,the maximum theoretically expected config-urational entropy difference at 875°C (the temperature were we observe the transition experimentally)between the single species and the random five-species solid solution is B 15kJ mol À1,5kJ mol À1larger than the calculated enthalpy of transition.It is possible that the origins of this difference are related to mixing energy as the reference energy values for structural transitions to rocksalt do not capture that aspect.While the present phase diagrams that monitor T trans as a function of composition demonstrate rather symmetric behaviour about the temperature minima,it is unlikely that mixing enthalpies are zero for all constituents.Indeed,literature reports show that enthalpies of mixing between the constituent oxides in E1are finite and of mixed sign,and their magnitudes are on the same order as the 5kJ mol À1difference between our calculated predictions 36.This energy difference may be accounted for by finite and positive mixing enthalpies.Following this argument,we can achieve a self-consistent appreciation for the entropic driving force and the enthalpic penalties for solution formation in E1by considering enthalpies of the associated structural transitions and expected entropy values for ideal cation mixing.As a final test,these predictions can be compared with experiment,specifically by calculating the magnitude of the endotherm observed by DSC at the transition from multiple-phase to single-phase states.Doing so we find a value B 12kJ mol À1(with an uncertainty of ±2kJ mol À1).While we acknowledge the challenge of quantitative calorimetry,we note that this experimental result is intermediate to and in close agreement with the predicted values.Compared with metallic alloys,the pronounced impact of entropy in oxides may be surprising given that on a per-atom basis the total disorder per volume of an oxide seems be lower than in a high-entropy alloy,as the anion sublattice is ordered (apart from point defects).The chemically uniform sublattice is perhaps the key factor that retains cation configurational entropy.As an illustration,consider a comparison between random metal alloys and random metal oxide alloys.Begin by reviewing the case of a two-component metallic mixture A–B.If the mixture is ideal,the energy of interaction E A–B ¼(E A–A þE B–B )/2,there is no enthalpic preference for bonding,and entropy regulates solution formation.In this scenario,all lattice sites are equivalent and configurational entropy is maximized.This situation,however,never occurs as no two elements have identical electronegativity and radii values.Figure 6a illustrates a two-component alloy scenario A–B where species B is more electronegative than A.Consequently,the interaction energies E A–A ,E B–B and E A–B will be different.A random mixture of A–B will produce lattice sites with a distribution of first near neighbours,that is,species A coordinated to 4-B atoms,2-A and 2-B atoms,etc y Different coordinations will have different energy values and the sites are no longer indistinguishable.Reducing the number of equivalent sites reduces the number of possible configurations and S .Now consider the same two metallic ions co-populating a cation sublattice,as in Fig.6b.In this case,there is always an intermediate anion separating neighbouring cation lattice sites.Again,in the limiting case where only first near neighboursareFigure 5|STEM–EDS analysis of E1.(a )HAADF image.Panels labelled as Zn,Ni,Cu,Mg and Co are intensity maps for the respective characteristic X-rays.The individual EDS maps show uniform spatial distributions for each element and are atomically resolved.considered,every cation lattice site is ‘identical’because each has the same immediate surroundings:the interior of an oxygen octahedron.Differentiation between sites is only apparent when the second near neighbours are considered.From the configura-tional disorder perspective,if each cation lattice site is identical,and thus energetically similar to all others,the number of microstates possible within the macrostate will approach the maximum value.This crystallographic argument is based on the limiting case where first-near-neighbour interactions predominate the energy landscape,which is an imperfect approximation.Second and third near neighbours will influence the distribution of lattice site energies and the number of equivalent microstates—but the impact will be the same in both scenarios.A larger number of equivalent sites in a crystal with an intermediate sublattice will increase S and expand the elemental diversity containable in a single solid solution and to lower the temperature at which the transition to entropic stabilization occurs.We acknowledge the hypothesis nature of this model at this time,and the need for a rigorous theoretical exploration.It is presented currently as a possibility and suggestion for future consideration and testing.We demonstrate that configurational disorder can promote reversible transformations between a poly-phase mixture and a homogeneous solid solution of five binary oxides,which do not form solid solutions when any of the constituents are removed provided the same thermal budget.The outcome is representative of a new class of materials called ‘entropy-stabilized oxides’.While entropic effects are known for oxide systems,for example,random cation occupancy in spinels 30,order–disorder transfor-mations in feldspar 38,and oxygen nonstoichiometry in layered perovskites 39,the capacity to actively engineer configurational entropy by composition,to stabilize a quinternary oxide with a single cation sublattice,and to stabilize unusual cation coordination values is new.Furthermore,these systems provide a unique opportunity to explore the thermodynamics and structure–property relationships in systems with extreme configurational disorder.Experimental efforts exploring this composition space are important considering that such compounds will be challenging to characterize with computational approaches minimizing formation energy (for example,genetic algorithms)or with adhoc thermodynamic models (for example,CALPHAD,cluster expansion)6.We expect entropic stabilization in systems where near-neighbour cations are interrupted by a common intermediateanion (or vice versa),which includes broad classes of chalcogenides,nitrides and halides;particularly when covalent character is modest.The entropic driving force—engineered by cation composition—provides a departure from traditional crystal-chemical principles that elegantly predict structural trends in the major ternary and quaternary systems.A companion set of structure–property relationships that predict new entropy-stabilized structures with novel cation incorporation await discovery and exploitation.MethodsSolid-state synthesis of bulk materials .MgO (Alfa Aesar,99.99%),NiO (Sigma Aldrich,99%),CuO (Alfa Aesar,99.9%),CoO (Alfa Aesar,99%)and ZnO (Alfa Aesar 99.9%)are massed and combined using a shaker mill and 3-mm diameter yttrium-stabilized zirconia milling media.To ensure adequate mixing,all batches are milled for at least 2h.Mixed powders are then separated into 0.500-g samples and pressed into 1.27-cm diameter pellets using a uniaxial hydraulic press at 31,000N.The pellets are fired in air using a Protherm PC442tube furnace.Temperature evolution of phases .Ceramic pellets of E1are equilibrated in an air furnace and quenched to room temperature by direct extraction from the hot zone.Phase analysis is monitored by X-ray diffraction using a PANalytical Empyrean X-ray diffractometer with Bragg-Brentano optics including programmable diver-gence and receiving slits to ensure constant illumination area,a Ni filter,and a 1-D 128element strip detector.The equivalent counting time for a conventional point detector would be 30s per point at 0.01°2y increments.Note that all X-ray are collected using substantial counting times and are plotted on a logarithmic scale.To the extent knowable using a laboratory diffractometer,the high-temperature samples are homogeneous and single phase:there are no additional minor peaks,the background is low and flat,and peak widths are sharp in two-theta (2y )space.Temperature-dependent diffraction data are collected with PANalytical Empyrean X-ray diffractometer with Bragg-Brentano optics includingprogrammable divergence and receiving slits to ensure constant illumination area,a Ni filter,and a 1-D 256element strip detector.The samples are placed in a resistively heated HTK-1200N hot stage in air.The samples are ramped at a constant rate of 5°C min À1with a theta–two theta pattern captured every 1.5min.Calorimetry data are collected using a Netzsch STA 449F1Jupiter system in a Pt crucible at 5°C min À1in flowing air.Determining solvus lines .Five series of powders are mixed where the amount of one constituent oxide is varied from the parent mixture E1.Supplementary Table 2lists the full set of samples synthesized for this experiment.Each individual sample is cycled through a heat-soak-quench sequence at 25°C increments from 850°C up to 1,150°C.The soak time for each cycle is 2h,and samples are then quenched to room temperature in o 1min.After the quenching step for each cycle,samples are immediately analysed for phase identification using a PANalytical Empyrean X-ray diffractometer using the conditions identified above.If more than one phase is present,the sample would be put through the next temperature cycle.The temperature at which the structure is determined to be pure rocksalt,with no discernable evidence of peak splitting or secondary phases,is deemed the transition temperature as a function of composition.Supplementary Fig.1shows an example of the collected X-raypatterns after each cycle using the E1L series with þ10%MgO.Once single phase is achieved,the sample is removed from the sequence.Note that this entire experiment is conducted two times.Initially in 50°C increments and longer anneals,and to ensure accuracy of temperature values and reproducibility,a second time using shorter increments and 25°C anneals.Findings in both sets are identical to within experimental error bar values.In the latter case,error bars correspond to the annealing interval value of 25°C.In the main text relating to Fig.2a we note that in addition to small peaks from second phases,X-ray spectra for N ¼4samples with either NiO or MgO removed show anisotropic peak broadening in 2y and skewed relative intensities where I (200)/I (111)is less than unity.This ratio is not possible for the rocksalt structure.Supplementary Table 3shows the result of calculations of structure factors for a random equimolar rocksalt oxide with composition E1.Calculations show that the 200reflection is the strongest,and that the experimentally measured relative intensities of 111/200are consistent with calculations.We use this information as a means too best assess when the transition to single phase occurs since the most likely reason for the skewed relative intensity is an incomplete conversion to the single-phase state.This dependency is highlighted in Supplementary Fig.1.X-ray absorption fine structure .X-ray absorption fine structure (XAFS)is made possible through the general user programme at the Advanced Photon Source in Lemont,IL (GUP-38672).This technique provides a unique way to probe the local environment of a specific element based on the interference between an emitted core electron and the backscattering from surrounding species.XAFS makes no assumption of structure symmetry or elemental periodicity,making it an ideal means to study disordered materials.During the absorption process,coreelectronsBFigure 6|Binary metallic compared with a ternary oxide.A schematic representation of two lattices illustrating how the first-near-neighbour environments between species having different electronegativity (the darker the more negative charge localized)for (a )a random binary metal alloy and (b )a random pseudo-binary mixed oxide.In the latter,near-neighbour cations are interrupted by intermediate common anions.。

星形胶质细胞rna提取 ## English Response: ##。

Materials.Brain tissue.Sterile dissecting instruments.RNAlater (Sigma-Aldrich)。

QIAzol Lysis Reagent (Qiagen)。

Chloroform.Isopropanol (cold)。

75% Ethanol (cold)。

RNase-Free Water.Microcentrifuge and tubes.Procedure.1. Harvest the brain tissue. Euthanize the animal and remove the brain. Carefully dissect the brain tissue of interest (e.g., hippocampus, cortex).2. Immerse the tissue in RNAlater. Transfer the dissected tissue to a tube containing RNAlater. Incubate overnight at 4°C.3. Lyse the tissue. Centrifuge the RNAlater-treated tissue at 12,000 x g for 10 minutes at 4°C. Remove the supernatant and resuspend the pellet in QIAzol Lysis Reagent. Homogenize the tissue using a tissue homogenizer or sonication.4. Extract the RNA. Add chloroform to the homogenized tissue and mix vigorously. Centrifuge at 12,000 x g for 15 minutes at 4°C. Transfer the upper aqueous phase to a newtube.5. Precipitate the RNA. Add isopropanol to the aqueous phase and mix. Centrifuge at 12,000 x g for 10 minutes at 4°C. Wash the RNA pellet with cold 75% ethanol.6. Resuspend the RNA. Centrifuge the RNA pellet at12,000 x g for 5 minutes at 4°C. Remove the ethanol andair-dry the pellet. Resuspend the RNA in RNase-Free Water.Quantification and Quality Assessment.Quantify the RNA concentration using a spectrophotometer (e.g., Nanodrop).Assess the RNA quality using an Agilent Bioanalyzer or similar platform.## 中文回答，##。

邹怡茜，陈海强，潘卓官，等. 超高压耦合热处理过程对鳙鱼鱼糜凝胶特性及水分迁移的影响[J]. 食品工业科技，2023，44（23）：70−79. doi: 10.13386/j.issn1002-0306.2023020083ZOU Yiqian, CHEN Haiqiang, PAN Zhuoguan, et al. Effects of Gel Properties and Water Migration during Ultra-High Pressure Coupled Heat Treatment on Bighead Carp Surimi[J]. Science and Technology of Food Industry, 2023, 44(23): 70−79. (in Chinese with English abstract). doi: 10.13386/j.issn1002-0306.2023020083· 研究与探讨 ·超高压耦合热处理过程对鳙鱼鱼糜凝胶特性及水分迁移的影响邹怡茜1，陈海强1,2，潘卓官1，周爱梅1,*（1.华南农业大学食品学院，广东广州 510642；2.阳江职业技术学院，广东阳江 529500）摘　要：为了阐明超高压耦合热处理过程中鳙鱼鱼糜凝胶特性变化的机制，本文探究了超高压耦合热处理（300 MPa/5 min ，40 ℃/30 min ，90 ℃/20 min ）过程中鳙鱼鱼糜凝胶特性、蛋白质结构及水分迁移的变化，并进行聚类热图和Pearson 相关性分析。

结果表明，超高压耦合热处理能显著改善鳙鱼鱼糜的凝胶特性（P <0.05）。

随着超高压，超高压结合一段热处理，超高压结合二段热处理过程的进行，鳙鱼鱼糜凝胶的凝胶强度、质构、白度呈上升趋势，其中，较常压处理样品（0.1P ），经超高压耦合热处理（300PSH ）的鱼糜凝胶强度和白度分别增加了477.75%、43.38%。

Cat. #R045AProduct ManualPrimeSTAR® Max DNAPolymeraseFor Research Usev201510DaTable of ContentsI. Description (3)II. Components (3)III. Storage (3)IV. General Composition of PCR Reaction Mixture (3)V. PCR Conditions (4)VI. Optimization of Parameters (6)VII. Features (7)VIII. Electrophoresis, Cloning, and Sequencing of Amplified Products (12)IX. Troubleshooting (12)X. Related Products (13)I. DescriptionPrimeSTAR Max DNA Polymerase is a unique high-performance DNA polymerase that possesses the fastest extension speed available, along with the extremely high accuracy, high sensitivity, high specificity, and high fidelity of PrimeSTAR HS DNA Polymerase. High priming efficiency and extension efficiency greatly reduces the time required for annealing and extension steps, facilitating exceptionally fast high-speed PCR reactions. In addition, standardization of extension step time makes PrimeSTAR Max DNA Polymerase suitable for reactions with large amounts of template DNA that would ordinarily be difficult to amplify. Furthermore, an antibody-mediated hot start formulation prevents false initiation events during the reaction assembly due to mispriming and primer digestion. Since PrimeSTAR Max DNA Polymerase is configured as a 2-fold premix containing reaction buffer and dNTP mixture, it allows quick preparation of reactions and is useful for high-throughput applications.II. Components (for 100 reactions, 50 μl volume)PrimeSTAR Max Premix (2X) 625 μl x 4＊ Containing 2 mM Mg2+ and 0.4 mM each dNTPIII. Storage–20℃Note: Repeated freeze-thaw of the Premix may reduce its activity.IV. General Composition of PCR Reaction MixtureFinal conc.PrimeSTAR Max Premix (2X)25 μl1XPrimer 110 - 15 pmol0.2 - 0.3 μMPrimer 210 - 15 pmol0.2 - 0.3 μMTemplate< 200 ng＊Sterile distilled water to reaction volume of 50 μl＊: Refer to VI. Optimization of ParametersCaution:The PCR reaction mixture can be prepared at room temperature. However,keep each of the reaction components on ice during the preparation process.V. PCR ConditionsWhen performing rapid amplification protocols using PrimeSTAR Max DNAPolymerase, 3-step reactions are recommended for best results and longestamplification products.(A) For reactions in which the quantity of template is 200 ng / 50 μl or less:＊98℃10 sec.55℃ 5 sec. or 15 sec.30 - 35 cycles72℃ 5 sec./kb(B) For reactions in which the quantity of template exceeds 200 ng / 50 μl:＊98℃10 sec.55℃ 5 sec. or 15 sec.30 - 35 cycles [3-step PCR]72℃30 - 60 sec./kbor98℃10 sec.30 - 35 cycles [2-step PCR]68℃30 - 60 sec./kb＊: For rapid amplification protocols (extension step of 5 to 10 sec./kb) withcDNA as template, use a quantity of template that is equal to or less thanthe equivalent of 125 ng of total RNA / 50 μl reaction.If larger quantites of cDNA template are desired, by setting a longerextension time (up to 1 min./kb), it is possible to use up to the equivalentof 750 ng total RNA / 50 μl reaction.See VII.C. Template Quantity and Reaction Speed Using cDNA as Template.・ Denaturing conditions: An initial denaturation step is not necessary for some PCRenzymes, including the PrimeSTAR polymerase series;98℃ for 10 seconds is sufficient for complete denaturation.During cycling, denaturation at 98℃ for 5 to 10 sec. isrecommended.Denaturation at 94℃ is also possible, but the time shouldbe extended to 10 to 15 sec.・ Annealing temperature: Use 55℃ as the default annealing temperature.・ Annealing time: For primers that are 25-mer or shorter:For primer T m values (calculated by the formula below) of55℃ or greater, anneal for 5 sec.For primer T m values (calculated by the formula below)less than 55℃, anneal for 15 sec.For primers longer than 25-mers:Use an annealing time of 5 sec.＊Tm value calculation:Tm (℃) = 2(NA + NT) + 4(NC + NG) - 5where N represents the number of primer nucleotides having thespecified identity (A, T, C, or G)・ Final elongation: This step is typically recommended for Taq polymerase, but isnot always necessary with PrimeSTAR Max polymerase.Important note:Because the priming efficiency of PrimeSTAR Max DNA Polymerase is extremely high, use an annealing time of 5 sec. or 15 sec. Longer annealing times may cause smearing of PCR products visible during electrophoresis analysis.If smearing occurs when performing a 3-step PCR protocol, try a 2-step PCR protocol. See VI. Optimization of Parameters and IX. Troubleshooting.VI. Optimization of ParametersIn order to obtain the best PCR results, it is important to optimize the PrimeSTAR Max DNAPolymerase reaction parameters to fully utilize the enzyme's properties and advantages.(1) Template DNARecommended quantities of template DNA (50 μl reaction) for rapid amplificationprotocols (extension step of 5 sec./kb):Human genomic DNA 5 ng - 200 ngE. coli genomic DNA 100 pg - 200 ngλDNA 10 pg - 10 ngPlasmid DNA 10 pg - 1 ngWhen using more than 200 ng of DNA as template in a 50 μl reaction, use anextension time of 30 to 60 sec./kb for best results.For rapid amplification protocols (extension time of 5 to 10 sec./kb) with cDNA astemplate, set the template cDNA quantity to ≦the equivalent of 25 to 125 ng total RNAper 50 μl reaction.See VI. C. Template Quantity and Reaction Speed Using cDNA as Template.Do not use templates containing uracil, such as bisulfite-treated DNA.(2) Amplified Product SizesAmplification product sizes using an extension time of 5 sec./kb (for genomic DNAtemplates) or 5 to 10 sec./kb (for cDNA templates):Human genomic DNA up to 6 kbE. coli genomic DNA up to 10 kbcDNA up to 6 kbλDNA up to 15 kbWhen amplifying targets in excess of these lengths, try using an extension time of 15to 30 sec./kb. In such instances, amplification is affected by the quantity, quality, andsequence composition of the template.(3) Primer and PCR ConditionsSelect primer sequences using primer design software such as OLIGO Primer AnalysisSoftware (Molecular Biology Insights, Inc.).For general amplification, 20 to 25-mer primers are suitable. When amplifying longerproducts, the use of 25 to 30-mer primers may improve results. See section V. PCRConditions.Do not use inosine-containing primers with PrimeSTAR Max DNA Polymerase.(4) Annealing conditionsSelect annealing conditions as described in V. PCR Conditions. If low product yieldoccurs, try the following:<If smearing and/or extra bands appear on agarose electrophoresis gels>(1) Shorten the annealing time. If performing at 15 sec., set to 5 sec.(2) If the annealing step has already been set to 5 sec., raise the annealingtemperature to 58℃ - 63℃.(3) Perform 2-step PCR.<If the target product is not amplified>(1) Lengthen the annealing time. If performing at 5 sec., set to 15 sec.(2) Lower the annealing temperature to 50℃ - 53℃.Good amplification is observed for products up to 6 kb in length using an extension time of 10 sec. and for products up to 8 kb in length using an extension time of 30 sec.When λDNA is used as template, extension time of 5 sec./kb may be suitable.(2) With human genomic DNA as template, amplification of products ranging in sizefrom 0.5 kb to 7.5 kb was performed using an annealing time of 5 sec. and an extension time of either 10 or 30 sec.Template Human genomic DNA [100 ng / 50 μl reaction]Thermal cyclerTaKaRa PCR Thermal Cycler Dice(Not available in all geographic locations. Check for availability in your region.)PCR conditions98℃10 sec.55℃ 5 sec.30 cycles72℃10 or 30 sec.M: λ-Hin d III digest[Extension time: 30 sec.]M1246810M (kb)8M1246(kb)10M [Extension time: 10 sec.]VII. FeaturesA. Rapid Amplification(1) With λDNA as template, amplification of products ranging in size from 1 to 10 kbwas performed using an annealing time of 5 sec. and an extension time of either 10 or 30 sec.Template λDNA [1 ng/50 μl reaction]Thermal cyclerTaKaRa PCR Thermal Cycler Dice™(Not available in all geographic locations. Check for availability in your region.)PCR conditions98℃10 sec.55℃ 5 sec.30 cycles72℃10 or 30 sec.M: λ-Hin d III digest[Extension time: 10 sec.]M 0.5123467.5M(kb)[Extension time: 30 sec.]M 0.5123467.5M (kb)Good amplification is observed for products up to 4 kb in length using an extension time of 10 sec, and for products up to 6 kb in length using an extension time of 30 sec. With human genomic DNA as template, an extension time setting of 5 sec./kb may be suitable.(3) With cDNA template, amplification of products ranging in size from 1 kb to 6 kb wasperformed using an annealing time of 15 sec. and an extension time of either 10 or 30 sec.Template cDNA [equivalent to 100 ng total RNA) / 50 μl reaction]Thermal cyclerTaKaRa PCR Thermal Cycler Dice(Not available in all geographic locations. Check for availability in your region.)PCR conditions98℃10 sec.55℃15 sec.30 cycles72℃10 or 30 sec.M: λ-Hind III digest[Extension time]M 1246M 1246M (kb)10 sec.30 sec.Good amplification was observed for products up to 2 kb in length using anextension time of 10 sec. and for products up to 4 kb using an extension time of 30 sec. With cDNA template, an extension time of 5 to 10 sec./kb is required.B. Length of amplification productsWith λDNA, E. coli genomic DNA, human genomic DNA, or cDNA as the template, amplification sizes of various DNA fragments were examined using an annealing time of 5 sec. or 15 sec. and an extension time of 5 sec./kb (genomic DNA) or 10 sec./kb (cDNA).Template:λDNA 1 ng E. coli genomic DNA 50 ng Human genomic DNA 100 ng cDNA equivalent to 100 ng total RNAThermal cycler:TaKaRa PCR Thermal Cycler Dice PCR conditions: 98℃10 sec.55℃ 5 or 15 sec.30 cycles 72℃ 5 (or 10) sec./kbGood amplification of products up to 6 kb in length was observed using an extension time of 5 sec./kb.[ Human genomic DNA ]M 246M1(kb)0.57.53M: λ-Hin d III digestGood amplification of products up to 6 kb in length was observed using an extension time of 10 sec./kb.[ cDNA ][λDNA ]Good amplification of products up to 15 kb inlength was observed using an extension time of 5 sec./kb.M: λ-Hin d III digestM2468101215M 1(kb)Good amplification of products up to 10 kb in length was observed using an extension time of 5 sec./kb.[ E. coli genomic DNA ]M246810M: λ-Hind III digestM (kb)M2468M 1（kb）M: λ-Hind III digestC. Template quantity and reaction rate using cDNA as templateAmplification of transferrin receptor (TFR) 4 kb in length was performed with cDNA as template. cDNA was obtained by reverse transcription of various amounts of total RNA, as indicated. The extension times were set to 20 sec (5 sec./kb), 2 min (30 sec./kb) or 4 min (1 min./kb), and the amplification efficiencies were compared.Template quantity (50 μl reaction)1 : cDNA equivalent to 25 ng total RNA 2 : cDNA equivalent to 50 ng total RNA 3 : cDNA equivalent to 125 ng total RNA 4 : cDNA equivalent to 250 ng total RNAM 1234567M 1234567M 1234567M5 : cDNA equivalent to 500 ng total RNA6 : cDNA equivalent to 750 ng total RNA7 : cDNA equivalent to 1 μg total RNA M : λ-Hind III digest1 min./kb5 sec./kb30 sec./kbM : λ-Hind III digestM 1234M 1234M 1234M 1234MHumangenomic DNA E. coli genomic DNAλDNAPlasmidTemplate quantity*:Lane 1 Lane 2 Lane 3 Lane 4Human genomic DNA 100 pg 1 ng 10 ng 100 ng E. coli genomic DNA 1 pg 10 pg 100 pg 1 ng λDNA100 fg 1 pg 10 pg 100 pg Plasmid DNA100 fg1 pg10 pg100 pgFor rapid amplification protocols using an extension time of 5 sec./kb, it is necessaryto use cDNA template that is ≦ the equivalent of 125 ng total RNA / 50 μl reaction. When using longer extension times (up to 1 min./kb), the quantity of cDNA template can be increased up to the equivalent of 750 ng total RNA / 50 μl reaction.D. SensitivityWith various amounts of human genomic DNA, E. coli genomic DNA, λDNA, orplasmid DNA as template, sensitivity was examined when amplification of a 4 kb DNA fragment was performed using an extension time of 20 sec.Thermal cycler TaKaRa PCR Thermal Cycler Dice PCR conditions98℃55℃72℃10 sec.5 sec.20 sec.30 cycles *: Observed limit of detection indicated by underline.E. AccuracyThe fidelity of PrimeSTAR Max DNA Polymerase was examined by analysis of sequenc-ing data.[ Method ] Eight arbitrarily selected GC-rich regions were amplified with PrimeSTARMax DNA Polymerase or other DNA polymerases, using Thermus ther-mophilus HB8 genomic DNA as template.PCR products (approx. 500 bp each) were each cloned into a suitable plas-mid. Multiple clones were selected per respective amplification productand were subjected to sequence analysis.[ Result ] Sequence analysis of DNA fragments amplified using PrimeSTAR Max DNAPolymerase demonstrated only 9 mismatched bases per 230,129 total bases. This is higher fidelity than an alternative high-fidelity enzyme from Company A, and 10-fold higher fidelity than Taq DNA polymerase.＊: Out of 230,129 analyzed bases that were amplified using PrimeSTARMax DNA Polymerase, only 9 base errors occurred.Fidelity comparison of each enzymem u t a t i o n f r e q u e n c y （%）0.060%0.050%0.040%0.030%0.020%0.010%0.000%PrimeSTARHSPrimeSTAR Max ＊Company A High FidelityEnzymePfuTaqVIII．Electrophoresis, Cloning, and Sequencing of Amplified Products1) ElectrophoresisTAE Buffer is recommended for agarose gel electrophoresis of amplified products that areobtained using PrimeSTAR Max DNA Polymerase.Note : Use of TBE Buffer may result in DNA band patterns that are enlarged at the bottom of the gel.2) Termini of amplified productsMost PCR products amplified with PrimeSTAR Max DNA Polymerase have blunt-endtermini. Accordingly, they can be cloned directly into blunt-end vectors. If necessary,phosphorylate the amplified products before cloning. Use of Mighty Cloning Reagent Set(Blunt End) (Cat. #6027)is recommended for cloning into a blunt-end vector.3) Restriction enzyme reactionPrior to performing restriction enzyme digestion of amplified PCR products, remove alltraces of PrimeSTAR Max DNA Polymerase from the reaction mixture by phenol/chloro-form extraction or by using NucleoSpin Gel and PCR Clean-up (Cat. #740609.10/.50/.250).Particularly for 3'-protruding restriction enzymes such as Pst I, the 3'-protruding terminiproduced by these enzymes may be deleted by 3' → 5' exonuclease activity of PrimeSTARMax DNA Polymerase, if residual polymerase remains present in the restriction digest reaction.4) Direct sequencingPerform phenol/chloroform extraction of PCR products prior to direct sequencing toensure inactivation of 3' → 5' exonuclease activity. Alternatively, NucleoSpin Gel and PCRClean-up (Cat. #740609.10/.50/.250) may be used to purify DNA prior to sequencing.IX. TroubleshootingEvent Possible causes ActionNo amplification orpoor amplification efficiency Extension time Set to 10 to 60 sec./kb *Number of cycles Set to 35 to 40 cycles.Annealing time Set to 15 sec.Annealing temperature Lower by 2℃ per trialReaction volume Use 25 μl.Purity and quantity oftemplate DNAUse an appropriate amount of template DNA.Purify the template DNA＊.Primer concentration Use 0.2 - 0.5 μM (final conc.).Electrophoresis analysis shows smeared band(s) or extra band(s)Annealing time Set to 5 sec.AnnealingtemperatureRaise by 2℃ per trial up to 63℃.Try 2-step PCR.Template DNAquantityUse an appropriate amount of template DNA.Do not use more than necessary.Number of cycles Set to 25 to 30 cycles.Primer concentration Use at a final concentartion of 0.2 - 0.3 μM.＊: When using crude samples containing large quantities of RNA, such as samples prepared by thermal lysis, improved results may be achieved by setting the extension time to60 sec./kb.X. Related ProductsPrimeSTAR® HS DNA Polymerase（Cat. #R010A/B）PrimeSTAR® HS (Premix) (Cat. #R040A)PrimeSTAR® GXL DNA Polymerase (Cat. #R050A/B）PrimeSTAR® Mutagenesis Basal Kit (Cat. #R046A)＊NucleoSpin Gel and PCR Clean-up (Cat. #740609.10/.50/.250）Mighty Cloning Reagent Set (Blunt End) (Cat. #6027)TaKaRa PCR Thermal Cycler Dice™ Gradient/Standard (Cat. #TP600/TP650)＊TaKaRa PCR Thermal Cycler Dice™ Touch (Cat. #TP350)＊＊ : Not available in all geographic locations. Check for availability in your region.PrimeSTAR is a registered trademark of TAKARA BIO INC.Thermal Cycler Dice is a trademark of TAKARA BIO INC.NOTE :This product is for research use only. It is not intended for use in therapeutic or diagnostic procedures for humans or animals. Also, do not use this product as food, cosmetic, orhousehold item, etc.Takara products may not be resold or transferred, modified for resale or transfer, or usedto manufacture commercial products without written approval from TAKARA BIO INC.If you require licenses for other use, please contact us by phone at +81 77 565 6973 orfrom our website at .Your use of this product is also subject to compliance with any applicable licensingrequirements described on the product web page. It is your responsibility to review,understand and adhere to any restrictions imposed by such statements.All trademarks are the property of their respective owners. Certain trademarks may not be registered in all jurisdictions.。

收稿日期：2023-07-23基金项目：海南省自然科学基金（318QN189）；海南省教育厅项目（Hnky2021-19，Qhys2021-248）作者简介：李雨欣（1999-），女，在读硕士生，研究方向为植物耐盐机理，E-mail：**********************通信作者：周扬（1988-），男，博士，副教授，研究方向为植物抗逆机理，E-mail：*********************.cn广东农业科学2023，50（10）：85-96Guangdong Agricultural SciencesDOI:10.16768/j.issn.1004-874X.2023.10.010李雨欣，王鹏，刘雯，周扬. 海马齿NHX 基因家族的鉴定及表达分析［J］. 广东农业科学，2023，50（10）：85-96.海马齿NHX 基因家族的鉴定及表达分析李雨欣，王 鹏，刘 雯，周 扬〔海南大学 热带农林学院（农业农村学院、乡村振兴学院）/海南省热带园艺作物品质调控重点实验室，海南 海口 570228〕摘 要：【目的】海马齿（Sesuvium portulacastrum L.）是典型的海岸植物和红树林伴生植物，能够固沙护岸，在海水中可以正常生长，具有极强的耐盐性。

Na +/H +逆向转运蛋白（Na +/H + exchange，NHX）在植物耐盐和生长发育中起关键作用，为了解NHX 在海马齿耐盐过程中的作用，对海马齿NHX 基因家族进行鉴定和分析。

【方法】采用生物信息学方法从海马齿全长转录组数据中鉴定NHXs 成员，对其蛋白理化性质、保守基序和进化关系进行分析，并利用荧光定量PCR 技术研究盐胁迫下NHXs 成员的表达模式。

【结果】从海马齿中共鉴定出12个SpNHX 基因，命名为SpNHX1~SpNHX12。

SpNHXs 基因编码的氨基酸长度为276~554 aa，分子量为31.22~61.21 kD，等电点为5.55~8.64，不稳定指数为32.14~50.54，均为疏水性蛋白。

第一章绪论一简答题1. 21世纪是生命科学的世纪。

20世纪后叶分子生物学的突破性成就，使生命科学在自然科学中的位置起了革命性的变化。

试阐述分子生物学研究领域的三大基本原则，三大支撑学科和研究的三大主要领域？答案：（1）研究领域的三大基本原则：构成生物大分子的单体是相同的；生物遗传信息表达的中心法则相同；生物大分子单体的排列（核苷酸，氨基酸）导致了生物的特异性。

（2）三大支撑学科：细胞学，遗传学和生物化学。

（3）研究的三大主要领域：主要研究生物大分子结构与功能的相互关系，其中包括DNA和蛋白质之间的相互作用；激素和受体之间的相互作用；酶和底物之间的相互作用。

2. 分子生物学的概念是什么？答案：有人把它定义得很广：从分子的形式来研究生物现象的学科。

但是这个定义使分子生物学难以和生物化学区分开来。

另一个定义要严格一些，因此更加有用：从分子水平来研究基因结构和功能。

从分子角度来解释基因的结构和活性是本书的主要内容。

3 二十一世纪生物学的新热点及领域是什么？答案：结构生物学是当前分子生物学中的一个重要前沿学科，它是在分子层次上从结构角度特别是从三维结构的角度来研究和阐明当前生物学中各个前沿领域的重要学科问题，是一个包括生物学、物理学、化学和计算数学等多学科交叉的，以结构（特别是三维结构）测定为手段，以结构与功能关系研究为内容，以阐明生物学功能机制为目的的前沿学科。

这门学科的核心内容是蛋白质及其复合物、组装体和由此形成的细胞各类组分的三维结构、运动和相互作用，以及它们与正常生物学功能和异常病理现象的关系。

分子发育生物学也是当前分子生物学中的一个重要前沿学科。

人类基因组计划，被称为“21世纪生命科学的敲门砖”。

“人类基因组计划”以及“后基因组计划”的全面展开将进入从分子水平阐明生命活动本质的辉煌时代。

目前正迅速发展的生物信息学，被称为“21世纪生命科学迅速发展的推动力”。

尤应指出，建立在生物信息基础上的生物工程制药产业，在21世纪将逐步成为最为重要的新兴产业；从单基因病和多基因病研究现状可以看出，这两种疾病的诊断和治疗在21世纪将取得不同程度的重大进展；遗传信息的进化将成为分子生物学的中心内容”的观点认为，随着人类基因组和许多模式生物基因组序列的测定，通过比较研究，人类将在基因组上读到生物进化的历史，使人类对生物进化的认识从表面深入到本质；研究发育生物学的时机已经成熟。