Two Photon Physics at LEP2 including data Monte-Carlo comparison

a r X i v :h e p -e x /0207007v 1 1 J u l 2002BELLEBelle Prerpint 2002-18KEK Preprint 2002-59Study of B →ρπdecays at BelleBelle Collaboration A.Gordon u ,Y.Chao z ,K.Abe h ,K.Abe aq ,N.Abe at ,R.Abe ac ,T.Abe ar ,Byoung Sup Ahn o ,H.Aihara as ,M.Akatsu v ,Y.Asano ay ,T.Aso aw ,V.Aulchenko b ,T.Aushev ℓ,A.M.Bakich an ,Y.Ban ag ,A.Bay r ,I.Bedny b ,P.K.Behera az ,jak m ,A.Bondar b ,A.Bozek aa ,M.Braˇc ko t ,m ,T.E.Browder g ,B.C.K.Casey g ,M.-C.Chang z ,P.Chang z ,B.G.Cheon am ,R.Chistov ℓ,Y.Choi am ,Y.K.Choi am ,M.Danilov ℓ,L.Y.Dong j ,J.Dragic u ,A.Drutskoy ℓ,S.Eidelman b ,V.Eiges ℓ,Y.Enari v ,C.W.Everton u ,F.Fang g ,H.Fujii h ,C.Fukunaga au ,N.Gabyshev h ,A.Garmash b ,h ,T.Gershon h ,B.Golob s ,m ,R.Guo x ,J.Haba h ,T.Hara ae ,Y.Harada ac ,N.C.Hastings u ,H.Hayashii w ,M.Hazumi h ,E.M.Heenan u ,I.Higuchi ar ,T.Higuchi as ,L.Hinz r ,T.Hokuue v ,Y.Hoshi aq ,S.R.Hou z ,W.-S.Hou z ,S.-C.Hsu z ,H.-C.Huang z ,T.Igaki v ,Y.Igarashi h ,T.Iijima v ,K.Inami v ,A.Ishikawa v ,H.Ishino at ,R.Itoh h ,H.Iwasaki h ,Y.Iwasaki h ,H.K.Jang a ℓ,J.H.Kang bc ,J.S.Kang o ,N.Katayama h ,Y.Kawakami v ,N.Kawamura a ,T.Kawasaki ac ,H.Kichimi h ,D.W.Kim am ,Heejong Kim bc ,H.J.Kim bc ,H.O.Kim am ,Hyunwoo Kim o ,S.K.Kim a ℓ,T.H.Kim bc ,K.Kinoshita e ,S.Korpar t ,m ,P.Krokovny b ,R.Kulasiri e ,S.Kumar af ,A.Kuzmin b ,Y.-J.Kwon bc ,nge f ,ai ,G.Leder k ,S.H.Lee a ℓ,J.Li ak ,A.Limosani u ,D.Liventsevℓ,R.-S.Lu z,J.MacNaughton k,G.Majumder ao, F.Mandl k,D.Marlow ah,S.Matsumoto d,T.Matsumoto au,W.Mitaroffk,K.Miyabayashi w,Y.Miyabayashi v,H.Miyake ae,H.Miyata ac,G.R.Moloney u,T.Mori d,T.Nagamine ar,Y.Nagasaka i,T.Nakadaira as,E.Nakano ad, M.Nakao h,J.W.Nam am,Z.Natkaniec aa,K.Neichi aq, S.Nishida p,O.Nitoh av,S.Noguchi w,T.Nozaki h,S.Ogawa ap, T.Ohshima v,T.Okabe v,S.Okuno n,S.L.Olsen g,Y.Onuki ac, W.Ostrowicz aa,H.Ozaki h,P.Pakhlovℓ,H.Palka aa,C.W.Park o,H.Park q,L.S.Peak an,J.-P.Perroud r, M.Peters g,L.E.Piilonen ba,J.L.Rodriguez g,F.J.Ronga r, N.Root b,M.Rozanska aa,K.Rybicki aa,H.Sagawa h,S.Saitoh h,Y.Sakai h,M.Satapathy az,A.Satpathy h,e,O.Schneider r,S.Schrenk e,C.Schwanda h,k,S.Semenovℓ,K.Senyo v,R.Seuster g,M.E.Sevior u,H.Shibuya ap,V.Sidorov b,J.B.Singh af,S.Staniˇc ay,1,M.Stariˇc m,A.Sugi v, A.Sugiyama v,K.Sumisawa h,T.Sumiyoshi au,K.Suzuki h,S.Suzuki bb,S.Y.Suzuki h,T.Takahashi ad,F.Takasaki h, K.Tamai h,N.Tamura ac,J.Tanaka as,M.Tanaka h,G.N.Taylor u,Y.Teramoto ad,S.Tokuda v,S.N.Tovey u,T.Tsuboyama h,T.Tsukamoto h,S.Uehara h,K.Ueno z, Y.Unno c,S.Uno h,hiroda h,G.Varner g,K.E.Varvell an,C.C.Wang z,C.H.Wang y,J.G.Wang ba,M.-Z.Wang z,Y.Watanabe at,E.Won o,B.D.Yabsley ba,Y.Yamada h, A.Yamaguchi ar,Y.Yamashita ab,M.Yamauchi h,H.Yanai ac,P.Yeh z,Y.Yuan j,Y.Yusa ar,J.Zhang ay,Z.P.Zhang ak,Y.Zheng g,and D.ˇZontar aya Aomori University,Aomori,Japanb Budker Institute of Nuclear Physics,Novosibirsk,Russiac Chiba University,Chiba,Japand Chuo University,Tokyo,Japane University of Cincinnati,Cincinnati,OH,USAf University of Frankfurt,Frankfurt,Germanyg University of Hawaii,Honolulu,HI,USAh High Energy Accelerator Research Organization(KEK),Tsukuba,Japani Hiroshima Institute of Technology,Hiroshima,Japanj Institute of High Energy Physics,Chinese Academy of Sciences,Beijing,PRChinak Institute of High Energy Physics,Vienna,Austria ℓInstitute for Theoretical and Experimental Physics,Moscow,Russiam J.Stefan Institute,Ljubljana,Slovenian Kanagawa University,Yokohama,Japano Korea University,Seoul,South Koreap Kyoto University,Kyoto,Japanq Kyungpook National University,Taegu,South Korear Institut de Physique des Hautes´Energies,Universit´e de Lausanne,Lausanne,Switzerlands University of Ljubljana,Ljubljana,Sloveniat University of Maribor,Maribor,Sloveniau University of Melbourne,Victoria,Australiav Nagoya University,Nagoya,Japanw Nara Women’s University,Nara,Japanx National Kaohsiung Normal University,Kaohsiung,Taiwany National Lien-Ho Institute of Technology,Miao Li,Taiwanz National Taiwan University,Taipei,Taiwanaa H.Niewodniczanski Institute of Nuclear Physics,Krakow,Polandab Nihon Dental College,Niigata,Japanac Niigata University,Niigata,Japanad Osaka City University,Osaka,Japanae Osaka University,Osaka,Japanaf Panjab University,Chandigarh,Indiaag Peking University,Beijing,PR Chinaah Princeton University,Princeton,NJ,USAai RIKEN BNL Research Center,Brookhaven,NY,USAaj Saga University,Saga,Japanak University of Science and Technology of China,Hefei,PR ChinaaℓSeoul National University,Seoul,South Koreaam Sungkyunkwan University,Suwon,South Koreaan University of Sydney,Sydney,NSW,Australiaao Tata Institute of Fundamental Research,Bombay,Indiaap Toho University,Funabashi,Japanaq Tohoku Gakuin University,Tagajo,Japanar Tohoku University,Sendai,Japanas University of Tokyo,Tokyo,Japanat Tokyo Institute of Technology,Tokyo,Japanau Tokyo Metropolitan University,Tokyo,Japanav Tokyo University of Agriculture and Technology,Tokyo,Japanaw Toyama National College of Maritime Technology,Toyama,Japanay University of Tsukuba,Tsukuba,Japanaz Utkal University,Bhubaneswer,Indiaba Virginia Polytechnic Institute and State University,Blacksburg,VA,USAbb Yokkaichi University,Yokkaichi,Japanbc Yonsei University,Seoul,South KoreaB events collected with the Belle detector at KEKB.Thebranching fractions B(B+→ρ0π+)=(8.0+2.3+0.7−2.0−0.7)×10−6and B(B0→ρ±π∓)=(20.8+6.0+2.8−6.3−3.1)×10−6are obtained.In addition,a90%confidence level upper limitof B(B0→ρ0π0)<5.3×10−6is reported.Key words:ρπ,branching fractionPACS:13.25.hw,14.40.Nd1on leave from Nova Gorica Polytechnic,Nova Gorica,Sloveniamodes are examined.Here and throughout the text,inclusion of charge con-jugate modes is implied and for the neutral decay,B0→ρ±π∓,the notation implies a sum over both the modes.The data sample used in this analysis was taken by the Belle detector[9]at KEKB[10],an asymmetric storage ring that collides8GeV electrons against3.5GeV positrons.This produces Υ(4S)mesons that decay into B0B pairs.The Belle detector is a general purpose spectrometer based on a1.5T su-perconducting solenoid magnet.Charged particle tracking is achieved with a three-layer double-sided silicon vertex detector(SVD)surrounded by a central drift chamber(CDC)that consists of50layers segmented into6axial and5 stereo super-layers.The CDC covers the polar angle range between17◦and 150◦in the laboratory frame,which corresponds to92%of the full centre of mass(CM)frame solid angle.Together with the SVD,a transverse momen-tum resolution of(σp t/p t)2=(0.0019p t)2+(0.0030)2is achieved,where p t is in GeV/c.Charged hadron identification is provided by a combination of three devices: a system of1188aerogelˇCerenkov counters(ACC)covering the momentum range1–3.5GeV/c,a time-of-flight scintillation counter system(TOF)for track momenta below1.5GeV/c,and dE/dx information from the CDC for particles with very low or high rmation from these three devices is combined to give the likelihood of a particle being a kaon,L K,or pion, Lπ.Kaon-pion separation is then accomplished based on the likelihood ratio Lπ/(Lπ+L K).Particles with a likelihood ratio greater than0.6are identified as pions.The pion identification efficiencies are measured using a high momentum D∗+data sample,where D∗+→D0π+and D0→K−π+.With this pion selection criterion,the typical efficiency for identifying pions in the momentum region0.5GeV/c<p<4GeV/c is(88.5±0.1)%.By comparing the D∗+data sample with a Monte Carlo(MC)sample,the systematic error in the particle identification(PID)is estimated to be1.4%for the mode with three charged tracks and0.9%for the modes with two.Surrounding the charged PID devices is an electromagnetic calorimeter(ECL) consisting of8736CsI(Tl)crystals with a typical cross-section of5.5×5.5cm2 at the front surface and16.2X0in depth.The ECL provides a photon energy resolution of(σE/E)2=0.0132+(0.0007/E)2+(0.008/E1/4)2,where E is in GeV.Electron identification is achieved by using a combination of dE/dx measure-ments in the CDC,the response of the ACC and the position and shape of the electromagnetic shower from the ECL.Further information is obtained from the ratio of the total energy registered in the calorimeter to the particle momentum,E/p lab.Charged tracks are required to come from the interaction point and have transverse momenta above100MeV/c.Tracks consistent with being an elec-tron are rejected and the remaining tracks must satisfy the pion identification requirement.The performance of the charged track reconstruction is studied using high momentumη→γγandη→π+π−π0decays.Based on the relative yields between data and MC,we assign a systematic error of2%to the single track reconstruction efficiency.Neutral pion candidates are detected with the ECL via their decayπ0→γγ. Theπ0mass resolution,which is asymmetric and varies slowly with theπ0 energy,averages toσ=4.9MeV/c2.The neutral pion candidates are selected fromγγpairs by requiring that their invariant mass to be within3σof the nominalπ0mass.To reduce combinatorial background,a selection criteria is applied to the pho-ton energies and theπ0momenta.Photons in the barrel region are required to have energies over50MeV,while a100MeV requirement is made for photons in the end-cap region.Theπ0candidates are required to have a momentum greater than200MeV/c in the laboratory frame.Forπ0s from BE2beam−p2B and the energy difference∆E=E B−E beam.Here, p B and E B are the momentum and energy of a B candidate in the CM frame and E beam is the CM beam energy.An incorrect mass hypothesis for a pion or kaon produces a shift of about46MeV in∆E,providing extra discrimination between these particles.The width of the M bc distributions is primarily due to the beam energy spread and is well modelled with a Gaussian of width 3.3MeV/c2for the modes with a neutral pion and2.7MeV/c2for the mode without.The∆E distribution is found to be asymmetric with a small tail on the lower side for the modes with aπ0.This is due toγinteractions withmaterial in front of the calorimeter and shower leakage out of the calorimeter. The∆E distribution can be well modelled with a Gaussian when no neutral particles are present.Events with5.2GeV/c2<M bc<5.3GeV/c2and|∆E|< 0.3GeV are selected for thefinal analysis.The dominant background comes from continuum e+e−→qB events and jet-like qi,j|p i||p j|P l(cosθij)i,k|p i||p k|,r l=),where L s and L qqD0π+ decays.By comparing the yields in data and MC after the likelihood ratiorequirement,the systematic errors are determined to be4%for the modes with aπ0and6%for the mode without.Thefinal variable used for continuum suppression is theρhelicity angle,θh, defined as the angle between the direction of the decay pion from theρin the ρrest frame and theρin the B rest frame.The requirement of|cosθh|>0.3 is made independently of the likelihood ratio as it is effective in suppressing the background from B decays as well as the qB events is used[14].The largest component of this background is found to come from decays of the type B→Dπ;when the D meson decays via D→π+π−,events can directly reach the signal region while the decay D→K−π+can reach the signal region with the kaon misidentified as a pion.Decays with J/ψandψ(2S) mesons can also populate the signal region if both the daughter leptons are misidentified as pions.These events are excluded by making requirements on the invariant mass of the intermediate particles:|M(π+π−)−M D0|>0.14 GeV/c2,|M(π+π0)−M D+|>0.05GeV/c2,|M(π+π−)−M J/ψ|>0.07GeV/c2 and|M(π+π−)−Mψ(2S)|>0.05GeV/c2.The widest cut is made around the D0mass to account for the mass shift due to misidentifying the kaons in D0 decays as pions.Fig.1shows the∆E and M bc distributions for the three modes analysed after all the selection criteria have been applied.The∆E and M bc plots are shown for events that lie within3σof the nominal M bc and∆E values,respectively. The signal yields are obtained by performing maximum likelihoodfits,each using a single signal function and one or more background functions.The signal functions are obtained from the MC and adjusted based on comparisons of B+→B0are assumed to be equal.The M bc distribution for all modes isfitted with a single Gaussian and an ARGUS background function[15].The normalization of the ARGUS function is left tofloat and shape of the function isfixed from the∆E sideband:−0.25 GeV<∆E<−0.08GeV and5.2GeV/c2<M bc<5.3GeV/c2.For the mode with only charged pions in thefinal state,the∆E distribution isfitted with a single Gaussian for the signal and a linear function withfixed shape for the continuum background.The normalization of the linear function is left to float and the slope isfixed from the M bc sideband,5.2GeV/c2<M bc<5.26GeV/c2,|∆E|<0.3GeV.There are also other rare B decays that are expected to contaminate the∆E distribution.For the mode without aπ0,these modes are of the type B0→h+h−(where h denotes aπor K),B→ρρ(including all combinations of charged and neutralρmesons,where the polarizations of theρmesons are assumed to be longitudinal)and B→Kππ(including the decays B+→ρ0K+,B+→K∗0π+,B+→K∗0(1430)0π+,B+→f0(980)K+ and B+→f0(1370)K+)[16].These background modes are accounted for by using smoothed histograms whose shapes have been determined by combining MC distributions.The three B→ρρmodes are combined into one histogram. The normalization of this component is allowed tofloat in thefit due to the uncertainty in the branching fractions of the B→ρρmodes.Likewise,the B→hh and all the B→Kππmodes are combined to form one hh and one Kππcomponent.The normalizations of these components arefixed to their expected yields,which are calculated using efficiencies determined by MC and branching fractions measured by previous Belle analyses[16,17].The∆Efits for the modes with aπ0in thefinal state have the signal compo-nent modelled by a Crystal Ball function[18]to account for the asymmetry in the∆E distribution.As for the B+→ρ0π+mode,the continuum background is modelled by a linear function withfixed slope.Unlike the B+→ρ0π+mode, a component is included for the background from the b→c transition.The pa-rameterization for rare B decays includes one component for the B→Kππ0 modes(B0→ρ+K−and B0→K∗+π−)[19]and one for all the B→ρρmodes.The normalization of the B→ρρcomponent is left tofloat while the other components from B decays arefixed to their expected yields.Table1summarizes the results of the∆Efits,showing the number of events, signal yields,reconstruction efficiencies,statistical significance and branching fractions or upper limits for eachfit.The statistical significance is defined assystematic error in thefitted signal yield is estimated by independently varying eachfixed parameter in thefit by1σ.Thefinal results are B(B+→ρ0π+)=(8.0+2.3+0.7−2.0−0.7)×10−6and B(B0→ρ±π∓)=(20.8+6.0+2.8−6.3−3.1)×10−6where thefirst error is statistical and the second is systematic.For theρ0π0mode,one standard deviation of the systematic error is added to the statistical limit to obtain a conservative upper limit at90%confidence of5.3×10−6.The possibility of a nonresonant B→πππbackground is also examined.To check for this type of background,the M bc and∆E yields are determined for differentππinvariant mass bins.Byfitting the M bc distribution inππinvariant mass bins with B→ρπand B→πππMC distributions,the nonresonant contribution is found to be below4%.To account for this possible background, errors3.7%and3.2%are added in quadrature to the systematic errors of the ρ+π−andρ0π+modes,respectively.Theππinvariant mass distributions are shown in Fig.2.Two plots are shown for theρ+π−andρ0π+modes,one with events from the M bc sideband superimposed over the events from the signal region(upper)and one with events from signal MC superimposed over events from the signal region with the sideband subtracted(lower).Fig.3 shows the distribution of the helicity variable,cosθh,for the two modes with all selection criteria applied except the helicity condition.Events fromρπdecays are expected to follow a cos2θdistribution while nonresonant and other background decays have an approximately uniform distribution.The helicity plots are obtained byfitting the M bc distribution in eight helicity bins ranging from−1to1.The M bc yield is then plotted against the helicity bin for each mode and the expected MC signal distributions are superimposed.Both the ππmass spectrum and the helicity distributions provide evidence that the signal events are consistent with being fromρπdecays.The results obtained here can be used to calculate the ratio of branching frac-tions R=B(B0→ρ±π∓)/B(B+→ρ0π+),which gives R=2.6±1.0±0.4, where thefirst error is statistical and second is systematic.This is consistent with values obtained by CLEO[20]and BaBar[21,22]as shown in Table2. Theoretical calculations done at tree level assuming the factorization approx-imation for the hadronic matrix elements give R∼6[3].Calculations that include penguin contributions,off-shell B∗excited states or additionalππres-onances[4–8]might yield better agreement with the the measured value of R.In conclusion,statistically significant signals have been observed in the B→ρπmodes using a31.9×106BWe wish to thank the KEKB accelerator group for the excellent operation of the KEKB accelerator.We acknowledge support from the Ministry of Ed-ucation,Culture,Sports,Science,and Technology of Japan and the Japan Society for the Promotion of Science;the Australian Research Council and the Australian Department of Industry,Science and Resources;the National Science Foundation of China under contract No.10175071;the Department of Science and Technology of India;the BK21program of the Ministry of Education of Korea and the CHEP SRC program of the Korea Science and Engineering Foundation;the Polish State Committee for Scientific Research under contract No.2P03B17017;the Ministry of Science and Technology of the Russian Federation;the Ministry of Education,Science and Sport of the Republic of Slovenia;the National Science Council and the Ministry of Education of Taiwan;and the U.S.Department of Energy.References[1] A.E.Snyder and H.R.Quinn,Phys.Rev.D48,2139(1993).[2]I.Bediaga,R.E.Blanco,C.G¨o bel,and R.M´e ndez-Galain,Phys.Rev.Lett.81,4067(1998).[3]M.Bauer,B.Stech,and M.Wirbel,Z.Phys.C34,103(1987).[4] A.Deandrea et al.,Phys.Rev.D62,036001(2000).[5]Y.H.Chen,H.Y.Cheng,B.Tseng and K.C.Yang,Phys.Rev.D60,094014(1999).[6] C.D.Lu and M.Z.Yang,Eur.Phys.J C23,275(2002).[7]J.Tandean and S.Gardner,SLAC-PUB-9199;hep-ph/0204147.[8]S.Gardner and Ulf-G.Meißner,Phys.Rev.D65,094004(2002).[9]Belle Collaboration,A.Abashian et al.,Nucl.Instr.and Meth.A479,117(2002).[10]E.Kikutani ed.,KEK Preprint2001-157(2001),to appear in Nucl.Instr.andMeth.A.[11]G.C.Fox and S.Wolfram,Phys.Rev.Lett.41,1581(1978).[12]This modification of the Fox-Wolfram moments wasfirst proposed in a seriesof lectures on continuum suppression at KEK by Dr.R.Enomoto in May and June of1999.For a more detailed description see Belle Collaboration,K.Abe et al.,Phys.Lett.B511,151(2001).[13]CLEO Collaboration,D.M.Asner et al.,Phys.Rev.D53,1039(1996).[14]These MC events are generated with the CLEO group’s QQ program,see/public/CLEO/soft/QQ.The detector response is simulated using GEANT,R.Brun et al.,GEANT 3.21,CERN Report DD/EE/84-1,1984.[15]The ARGUS Collaboration,H.Albrecht et al.,Phys.Lett.B241,278(1990).[16]Belle Collaboration,A.Garmash et al.,Phys.Rev.D65,092005(2002).[17]Belle Collaboration,K.Abe et al.,Phys.Rev.Lett.87,101801(2001).[18]J.E.Gaiser et al.,Phys.Rev.D34,711(1986).[19]Belle Collaboration,K.Abe et al.,BELLE-CONF-0115,submitted as acontribution paper to the2001International Europhysics Conference on High Energy Physics(EPS-HEP2001).[20]CLEO Collaboration,C.P.Jessop et al.,Phys.Rev.Lett.85,2881(2000).[21]Babar Collaboration,B.Aubert et al.,submitted as a contribution paper tothe20th International Symposium on Lepton and Photon Interactions at High Energy(LP01);hep-ex/0107058.[22]BaBar Collaboration,B.Aubert et al.,submitted as a contribution paper tothe XXXth International Conference on High Energy Physics(ICHEP2000);hep-ex/0008058.Table1∆Efit results.Shown for each mode are the number of events in thefit,the signal yield,the reconstruction efficiency,the branching fraction(B)or90%confidence level upper limit(UL)and the statistical significance of thefit.Thefirst error in the branching fraction is statistical,the second is systematic.ρ0π+15424.3+6.9−6.29.68.0+2.3+0.7−2.0−0.74.4σρ+π−30144.6+12.8−13.46.820.8+6.0+2.8−6.3−3.13.7σρ0π0116−4.4±8.58.5<5.3-Experiment B(B0→ρ±π∓)×10−6B(B+→ρ0π+)×10−6RE v e n t s /16 M e VE v e n t s /3 M e V /c2(b) ρ0π+Signal backgrd02.557.51012.51517.52022.55.25.225 5.25 5.2755.3E v e n t s /18 M e VE v e n t s /2 M e V /c2(d) ρ+π-Signal backgrd051015202530355.25.225 5.25 5.2755.3∆E(GeV)E v e n t s /18 M e V(e) ρ0π024681012-0.2-0.10.10.2(GeV/c 2)E v e n t s /2 M e V /c2M bc (f) ρ0πSignal backgrd02468101214165.25.225 5.25 5.2755.3Fig.1.The ∆E (left)and M bc (right)fits to the three B →ρπmodes:ρ0π+,ρ+π−and ρ0π0.The histograms show the data,the solid lines show the total fit and the dashed lines show the continuum component.In (a)the contribution from the B →ρρand B →hh modes is shown by the cross hatched component.In (c)the cross hatched component shows the contribution from the b →c transition and B →ρρmodes.102030405060+0(GeV/c 2)E v e n t s /0.1 G e V /c2M(π+π0)(GeV/c 2)E v e n t s /0.1 G e V /c2(GeV/c 2)E v e n t s /0.1 G e V /c2+-(GeV/c 2)E v e n t s /0.1 G e V /c2M(π+ π-)510152025Fig.2.The M (ππ)distributions for B 0→ρ±π∓(left)and B +→ρ0π+(right)events in the signal region.Plots (a)and (b)show sideband events superimposed;plots (c)and (d)show the sideband subtracted plots with signal MC superimposed.-1-0.500.51M b c y i e l d (E v e n t s )cos θh-1-0.500.51M b c y i e l d (E v e n t s )cos θhFig.3.The ρmeson helicity distributions for B 0→ρ±π∓(a)and B +→ρ0π+(b).Signal MC distributions are shown superimposed.。

max S max S
(1) 按讲义中的电路原理图连接好实物电路图； (2) 测光电管的伏安特性曲线： ① 先使正向电压加至30伏以上，同时使光电流达最大（不超量程）， ② 将电压从0开始按要求依次加大做好记录； (3) 测照度与光电流的关系： ① 先使光电管距光源20cm处，适当选择光源亮度使光电流达最大(不超量程)； ② 逐渐远离光源按要求做好记录； 实验步骤 (4) 测光电管的截止电压： ① 将双向开关换向； ② 使光电管距光源20cm处，将电压调至“0”， 适当选择光源亮度使光电流达最大（不超量程），记录此时的光 电流I ，然后加反向电压使光电流刚好为“0”，记下电压值U ； ③ 使光电管远离光源（光源亮度不变）重复上述步骤作好记录。 数据处理
k
(a + b) sin ψ
k
如果人射光不是单色，则由上式可以看出，光的波长不同，其衍射角也各不相同，于是复色光将被分解，而在中央 k =0、 ψ =0 处，各色光仍重叠在一起，形成中央明条纹。在中央明条纹两侧对称地分布着 k=1，2，3，…级光谱 ，各级光谱 线都按波长大小的顺序依次 排列成一组彩色谱线，这样就把复色光分解为单色光。如果已知光栅常数，用分光计测出 k 级光谱中某一明条纹的衍射角ψ，即可算出该明条纹所对应的单色光的波长λ。 实验步骤 (1) 调整分光计的工作状态，使其满足测量 条件。 (2) 利用光栅衍射 测量汞灯在可见光范 围内几条谱线的波长。 ① 由于衍射光谱在中央明条纹两侧对 称地分布，为了提高测量的准确度，测量第k级光谱时 ，应测出 +k级和-k 级光谱线的位置，两位置的差值之 半即为实验时 k取1 。 ② 为了减少分光计刻度盘的偏心误差，测量每条光谱线时 ，刻度盘上的两个游标都要读数 ，然后取其平均值 (角 游标的读数方法与游 标卡尺的读数方法基本一致)。 ③ 为了使十字丝对准光谱线，可以使用望远镜微调螺钉12来对准。 ④ 测量时，可将望远 镜置最右端，从 -l 级到 +1 级依次测量，以免漏测数据。 数据处理 谱线 游标 左1级 (k=-1) 右1级 (k=+1) φ λ／nm λ ／nm

Journal of Steroid Biochemistry &Molecular Biology 127 (2011) 196–203Contents lists available at ScienceDirectJournal of Steroid Biochemistry and MolecularBiologyj o u r n a l h o m e p a g e :w w w.e l s e v i e r.c o m /l o c a t e /j s b mbReviewEcdysteroid metabolism in crustaceans ଝDonald L.Mykles ∗Department of Biology,Colorado State University,Campus 1878,Fort Collins,CO 80523,USAa r t i c l ei n f oArticle history:Received 27July 2010Received in revised form 1September 2010Accepted 2September 2010Keywords:Crustacean MoltingEcdysteroid biosynthesis Ecdysteroid metabolism Ecdysteroid excretion Halloween genes Reviewa b s t r a c tThe molting gland,or Y-organ (YO),is the primary site for ecdysteroid synthesis in decapod crus-taceans.Ecdysteroid biosynthesis is divided into two stages:(1)conversion of cholesterol to 5␤-diketol and (2)conversion of 5␤-diketol to secreted products.Stage 1involves the conversion of cholesterol to 7-dehydrocholesterol (7DC)by 7,8-dehydrogenase,the “Black Box”reactions involving 3-oxo- 4intermediates,and the conversion of 4-diketol to 5␤-diketol by 5␤[H]-reductase.The stage 2reactions generate four major products,depending on species:ecdysone,3-dehydroecdysone (3DE),25-deoxyecdysone (25dE),and 3-dehydro-25-deoxyecdysone (3D25dE).Peripheral tissues convert these compounds to the active hormones 20-hydroxyecdysone (20E)and ponasterone A (25-deoxy-20-hydroxyecdysone or 25d20E).The hydroxylations at C25,C22,C2,and C20are catalyzed by cytochrome P-450mono-oxygenases,which are encoded by the Halloween genes Phantom ,Disembodied ,Shadow ,and Shade ,respectively,in insects.Orthologs of these genes are present in the Daphnia genome and a cDNA encoding Phantom has been cloned from prawn.Inactivation involves conversion of ecdys-teroids to polar metabolites and/or conjugates,which are eliminated in the urine and feces.The antennal gland is the major route for excretion of ecdysteroids synthesized by the YO.The hepatopancreas eliminates ingested ecdysteroids by forming apolar conjugates.The concentrations of ecdysteroids vary over the molt cycle and are determined by the combined effects biosynthesis,metabolism,and excretion.© 2010 Elsevier Ltd. All rights reserved.Contents 1.Introduction ..........................................................................................................................................1962.Ecdysteroid synthesis by the Y-organ ...............................................................................................................1973.Hemolymph ecdysteroids over the molt cycle ......................................................................................................1994.Ecdysteroid metabolism and excretion ..............................................................................................................2005.Conclusions and summary ...........................................................................................................................201Acknowledgements ..................................................................................................................................201References ...........................................................................................................................................2011.IntroductionEcdysteroids are polyhydroxylated C27steroids that control molting in arthropods.As the research on crustaceans has lagged behind that on insects,it comes as no surprise that what we have learned from insects has provided insights and guided the work on crustaceans.This review is restricted to ecdysteroid biosynthesis in the crustacean molting gland,or Y-organ (YO),and ecdysteroid metabolism and excretion by peripheral tissues.It emphasizesଝArticle submitted for the special issue on Marine organisms.∗Tel.:+19704917616;fax:+19704910649.E-mail address:don@ .research published over the last 20years.The reader is referred to [1–7]for comprehensive reviews of the earlier work.As most of the work has focused on decapod crustaceans,little is known about ecdysteroid biosynthetic pathways in other crustacean groups.Data from non-decapod crustaceans are included where appropriate.Due to space limitations,related topics are not covered.The reader is referred to reviews on the biochemistry of vertebrate-type steroids [8–10],endocrine disruptors [11–13],and the role of ecdysteroids on reproduction and larval development in crus-taceans [9,10,12,14].Moreover,recent reviews provide detailed treatment on the regulation of YO ecdysteroidogenesis by eyestalk neuropeptides [15–18].0960-0760/$–see front matter © 2010 Elsevier Ltd. All rights reserved.doi:10.1016/j.jsbmb.2010.09.001D.L.Mykles /Journal of Steroid Biochemistry &Molecular Biology 127 (2011) 196–2031972.Ecdysteroid synthesis by the Y-organCholesterol is the precursor for ecdysteroid synthesis in the YO.The YOs are located in the cephalothorax,anterior to the branchial chamber.They are epithelioid tissues with cells contain-ing numerous mitochondria and extensive endoplasmic reticulum,which is characteristic of steroidogenic tissues of vertebrates [1,2,19].Arthropods cannot synthesize cholesterol de novo ,and therefore acquire it from their diet [3,20,21].Cholesterol binds to high-density lipoproteins in the hemolymph and is taken up by the YO [20–26].The uptake of cholesterol is an important rate-limiting step in the synthesis of ecdysteroids and is regulated by eyestalk neuropeptides,such as molt-inhibiting hormone (MIH)[21–23,27,28].Ecdysteroid biosynthesis in the molting glands of insects and crustaceans is similar,but the crustacean YO synthesizes a greater diversity of ecdysteroids [1,3,4,29,30].The biosynthetic pathway in the crustacean YO is complex.For convenience,ecdysteroid biosyn-thesis can be divided into two stages:(1)conversion of cholesterol to 5␤-diketol (Fig.1)and (2)conversion of 5␤-diketol to secreted products (Fig.2).The first stage of ecdysteroid synthesis is common to all decapod species.The second stage has four pathways with branching points at 5␤-diketol and 5␤-ketodiol [1,31,32].These pathways are named for the final ecdysteroid product secreted by the YO:ecdysone,3-dehydroecdysone (3DE),25-deoxyecdysone (25dE),and 3-dehydro-25-deoxyecdysone (3D25dE).YOs usually secrete two products,indicating that only two of the potential four pathways are operational at any given time in one species.This appears to be due to the relative activities of enzymes at the branch points,which directs metabolites along particular pathways.Cholesterol7-Dehydrocholesterol (7DC)5β-Diketol (3D2,22,25,dE)Non-molting glossy (Nm-g)/Shroud (Sro)Spook (Spo)/Spookier (Spok)Spookiest (Spot)Neverland (Nvd)(7,8-Dehydrogenase)5β[H]-Reductase“B l a c k B o x ”Δ -Diketol4Fig.1.Stage 1of the ecdysteroid biosynthetic pathway in crustacean molting gland (Y-organ).In the first reaction,cholesterol is converted to 7-dehydrocholesterol (7DC)by 7,8-dehydrogenase,encoded by the Neverland (nvd )gene in insects.In a series of reactions involving enzymes encoded by non-molting glossy /shroud ,Spook /Spookier ,and Spookiest ,termed the “Black Box”,7DC is converted to 4-Diketol,which is converted to 5␤-diketol by 5␤[H]-reductase.Modified from [1,29,31].Much of what we know about the biosynthetic pathway in the YO comes from metabolic studies using radiolabelled precursors.The first step is the conversion of cholesterol to 7-dehydrocholesterol (7DC)by 7,8-dehydrogenase;the two H(␤)at carbons #7and #8are removed,resulting in the formation of a double bond between those carbons (Fig.1).Studies on a vari-ety of decapod crustacean species have shown that radiolabelled cholesterol injected into animals is converted to ecdysone,3DE,20-hydroxyecdysone (20E),25dE,3-dehydro-20-hydroxyecdysone (3D20E),and/or ponasterone A (PA;25-deoxy-20E or 25d20E)[21,26,33–35].A [3H]3␤-hydroxy- 4compound is poorly metab-olized by YO cells,indicating that the 3-oxo group is required for efficient 5␤-reduction [36].[3H]25-hydroxycholesterol (25C)is converted to 7-dehydro-25C by the YOs of green crab (Carci-nus maenas ),shrimp (Penaeus vannamei ),and crayfish (Orconectes limosus );the 7-dehydro-25C is converted to 3DE in C.maenas or to ecdysone and 3DE in P.vannamei and O.limosus [37].The YOs from Cancer antennarius can also synthesize 3DE from 25C [38].Although it is not a normal intermediate in the pathway,these results show that 25C can be a substrate for 7,8-dehydrogenase.The uptake of 25C is much faster than cholesterol,which makes it a useful tool for the study of the regulation of ecdysteroidogenesis [37,38].The 7DC undergoes a series of reactions involving 3-oxo- 4intermediates [36],the so-called “Black Box”,the details of which are becoming clearer [39].YO cells from C.maenas convert a 25-deoxy-3-oxo- 4intermediate to 3DE and 25dE;no ecdysone was detected [36].However,YO cells convert a 3-oxo- 4intermediate hydroxylated at C25to 3DE and ecdysone [36].This is consistent with studies showing that these ecdysteroids are synthesized from 25C as the precursor [32,37,38].The part of the pathway after the “Black Box”reactions is bet-ter understood,particularly the hydroxylations at C2,C22,and C25,which increase the polarity of the secreted products. 4-Diketol is first reduced at C5by 5␤[H]-reductase to form 5␤-diketol (Fig.2;3-dehydro-2,22,25-deoxyecdysone or 3D2,22,25dE).5␤-Diketol is converted to 5␤-ketodiol (2,22,25-deoxyecdysone or 2,22,25dE)by 3-dehydroecdysteroid-3␤-reductase (Fig.2)[31].In C.maenas ,[3H]5␤-diketol is ultimately converted to 3DE and 25dE by C.mae-nas YO cells [36].[3H]5␤-ketodiol is hydroxylated at C2,C22,or C25in C.maenas YOs to produce 22,25-deoxyecdysone (22,25dE),2,25-deoxyecdysone (2,25dE),or 2,22-dideoxyecdysone (2,22dE),respectively [40–42].2,22dE and 2,25dE are converted to ecdysone and 25dE,respectively,and secreted by the YO [40,41].22,25dE is not processed further and is not secreted [40,41].In the YOs of crayfish,[3H]5␤-diketol is converted to ecdysone and 3DE,whereas [3H]5␤-ketodiol is converted to ecdysone [31].The major secreted products of the YO are ecdysone,3DE,3D25dE,and 25dE,but the relative amounts vary among species.Four patterns are observed in decapod crustaceans (Table 1).TheTable 1Major ecdysteroid products secreted by the Y-organs of decapod crustaceans.The production of 25dE in U.pugilator is suggested by high hemolymph titers of ponas-terone A in premolt animals [30,49].SpeciesE a3DE a 25dE a 3D25dE aPachygrapsus crassipes •Cancer antennarius ••Orconectes limosus ••Procambarus clarkii ••Penaeus vannamei••Macrobrachium rosenbergii ••Carcinus maenas ••Callinectes sapidus ••Uca pugilator••Menippe mercenaria••aAbbreviations :E,ecdysone;3DE,3-dehydroecdysone;25dE,25-deoxyecdysone;3D25dE,3-dehydro-25-deoxyecdysone.198 D.L.Mykles /Journal of Steroid Biochemistry &Molecular Biology 127 (2011) 196–2035b- Diketol (3D2,22,25dE)5b -Ketodiol (2,22,25dE)5b- Ketotriol (2,22dE)20-Hydroxyecdysone (20E)b -reductase3-Dehydro-2,22-deoxyecdysone (3D2,22dE)3-Dehydro-2-deoxyecdysone (3D2dE)Disembodie 2,25-deoxyecdysone (2,25dE)Y-OrganPeripheral tissues3-Dehydroecdysone25-deoxyecdysone (25dE)Ponasterone A (PA)3-Dehydro-2,25-deoxyecdysone (3D2,25dE)3-Dehydro-25-deoxyecdysone (3D25dE)3-Dehydro-25-deoxyecdysone b -R(3D20E)Ponasterone A (PA)Fig.2.Stage 2of the ecdysteroid biosynthetic pathway in crustacean molting gland (Y-organ).Data indicate that there are two branching points,resulting in four pathways and four products secreted from the Y-organ.The products vary with species and molt stage,but no more than two major products are usually secreted at one time.3␤-Reductase and 20-hydroxylase activities in peripheral tissues convert the secreted products to the compounds circulating in the hemolymph.Therefore,the ecdysteroids in the hemolymph are determined by the compounds secreted by the YO and the activities of 3␤-reductase and 20-hydroxylase.All the compounds metabolized by peripheral tissues are detected in hemolymph samples;the major ecdysteroids in hemolymph are 20E,PA,3D20E,and 25d20E.In M.mercenaria ,a potential metabolite,3-dehydro-25-deoxy-20-hydroxyecdysone (3D25d20E),resulting from the 20-hydroxylation of 3D25dE has not been identified [32].The terminal hydroxylations at carbons #25,#22,#2,and #20are catalyzed by cytochrome P450mono-oxygenases encoded by Phantom (phm ),Disembodied (dib ),Shadow (sad ),and Shade (shd ),respectively.The specificities of these enzymes are such that the hydroxylations occur in the same order:C25→C22→C2→C20.Hence,hydroxylation at a specific carbon prevents hydroxylation by enzymes “upstream”of that step.For example,hydroxylation at C2prevents hydroxylations at C25and C22.Modified from [1,29,31,32].YOs in crayfish (O.limosus and Procambarus clarkii ),shrimp (P.vannamei and Macrobrachium rosenbergii ),and rock crab (C.anten-narius )secrete ecdysone and 3DE [25,31,43–46],the YOs in green crab (C.maenas )and blue crab (Callinectes sapidus )secrete ecdysone and 25dE [34,41](unpublished data on C.sapidus cited in [32]),theYOs in stone crab (Menippe mercenaria )secrete 3DE and 3D25dE [27,32],and the YOs in lined shore crab (Pachygrapsus crassipes )and fiddler crab (Uca pugilator )secrete ecdysone [47,48].However,the high levels of PA in the hemoymph of premolt U.pugilator indicate that the YO of this species also secretes 25dE in addition to ecdysoneD.L.Mykles/Journal of Steroid Biochemistry&Molecular Biology127 (2011) 196–203199[49].This suggests that the biosynthetic pathway has branching points at5␤-diketol and5␤-ketodiol,leading to fourfinal ecdys-teroid products(Fig.2).At thefirst branching point5␤-diketol can be converted to5␤-ketodiol,3-dehydro-2,22-deoxyecdysone (3D2,22dE),or3-dehydro-2,25-deoxyecdysone(3D2,25dE)(Fig.2). At the second branching point5␤-ketodiol can be converted to either5␤-ketotriol or2,25-deoxyecdysone(2,25dE),which leads to the production of ecdysone or25dE,respectively(Fig.2).In the pathway leading to ecdysone,5␤-ketodiol is hydroxylated sequen-tially at C25,C22,and C2[1].At thefirst branching point,5␤-diketol is hydroxylated at C25to3D2,22dE;subsequent serial hydroxyla-tions of3D2,22dE at C22and C2produce3DE[31].[3H]-3D2,22dE is converted to3DE and ecdysone by C.maenas YO cells[36].In M.mercenaria,5␤-diketol is apparently hydroxylated at C22to 3D2,25dE;subsequent hydroxylation at C2produces3D25dE[32]. At the second branching point,5␤-ketodiol is hydroxylated at C22 to2,25-deoxyecdysone(2,25dE);subsequent hydroxylation at C2 produces25dE.The branching points in the YO ecdsteroid synthetic pathway suggest that the P450mono-oxygenases,encoded by the Hal-loween genes Phantom(phm),Disembodied(dib),Shadow(sad), and Shade(shd)can bind multiple substrates.Phm apparently can hydroxylate5␤-diketol or5␤-ketodiol at C25;Dib apparently can hydroxylate5␤-diketol,3D2,22dE,5␤-ketodiol,or5␤-ketotriol at C22;Sad apparently can hydroxylate3D2dE,2,25dE,or2dE at C2; and Shd apparently can hydroxylate25dE,3DE,or ecdysone at C20 (Fig.2).However,the specificities of the Phm,Dib,Sad,and Shd enzymes are such that the C25→C22→C2→C20order of hydrox-ylations is maintained(Fig.2)[3,29].For example,compounds hydroxylated at C22(2,25dE and25dE)cannot be hydroxylated at C25in the YO from C.maenas[40].Hydroxylation at C2(22,25dE) prevents hydroxylations at C22and C25[1,40].Ecdysteroid biosynthetic reactions are catalyzed by reductases and P450mono-oxygenases(CYPs).The reduction of cholesterol to 7DC(Fig.1)is catalyzed by a7,8-dehydrogenase,which is encoded by the Neverland(nvd)gene in insects and nematode[50].The Nvd protein has two conserved domains involved in catalysis:a Rieske-like domain containing a2Fe-2S binding motif and a C-terminal domain containing a non-heme Fe(II)-binding motif[50]. Halloween genes constitute a family of P450mono-oxygenases, which have been well characterized in insects[29].They are char-acterized by havingfive conserved structural motifs(Helix-C or WxxxR sequence,Helix-I or GxE/DDT/S sequence,Helix-K or ExxR sequence,PERF motif or PxxFxPE/DRF sequence,and heme-binding or PFxxGxRxCxG/A sequence),as well as six substrate recogni-tion sites(SRS1,2/3,4,5,and6)[51].The“Black Box”reactions are catalyzed by non-molting glossy(nm-g)/shroud(sro)and sev-eral Halloween genes:spook(spo)and its paralog spookier(spok); and spookiest(spot)[51,52].Spo and Phm belong to the CYP2clade of P450enzymes and are associated with the endoplasmic reticu-lum(ER),whereas Dib,Sad,and Shd are associated with the inner membrane of the mitochondrion[29,53–55].Nm-g/sro encodes a short-chain NAD(P)H dehydrogenase/reductase,which appears to act upstream of Spo[52].Nm-g/sro has an N-terminal NADP/NAD binding domain and a central catalytic domain and is expressed primarily in prothoracic gland and ovary[52].Crustaceans appear to have the same enzymes for ecdysteroid biosynthesis as insects.An inhibitor of steroid5␣-reductase,L-645390,blocks the conversion of cholesterol to7DC in the YO of M.mercenaria[22].The5␤-reductase that converts 4-diketol to 5␤-diketol is a cytosolic enzyme in YO cells that requires NADPH for activity[36].Orthologs of nvd,nm-g/sro,spo,phm,dib,sad,and shd have been identified in the Daphnia pulex genome[52,54,56], and a cDNA encoding Phm has been cloned from Kuruma prawn, Marsupenaeus japonicus[57].Nvd and spo are located adjacent to each other in the D.pulex genome[54].The M.japonicus Phm and D.pulex Phm havefive conserved motifs present in insect Phm(WxxxR,GxE/DTT/S,ExxR,PxxFxPE/DRF,and PFxxGxRxCxG/A heme-binding motif),five of six substrate recognition sites(SRS 1,2/3,4,and5),and N-terminal ER-targeting and Pro/Gly-rich sequences[57].Mj-Phm is a target of eyestalk neuropeptides,as its expression in the YO is increased as much as7-fold during premolt and is decreased about2.5-fold by sinus gland extract and recom-binant MIH[57].None of the crustacean Halloween enzymes have been characterized biochemically.A member of the clade4of cytochrome P450enzymes has been cloned from O.limosus(CYP4C15)and C.maenas(CYP4C39) [58,59].Both genes encode proteins with hydrophobic N-terminal ER-targeting and Pro/Gly-rich sequences characteristic of microso-mal cytochrome P450enzymes[58,59].CYP4C15is expressed in the YO and the protein is associated with the ER[58,60].More-over,CYP4C15expression in the YO is increased during premolt and is decreased by MIH[58,60].These data suggest that they are involved in ecdysteroid biosynthesis,but their precise role remains to be determined.It has been hypothesized that the gene cat-alyzes7,8-dehydrogenation or25-hydroxylation[58,60].However, CYP4C15and CYP4C39have low sequence identity/similarity to nvd and phm,making it unlikely that these genes are involved in7,8-dehydrogenation and25-hydroxylation,respectively,in the YO. CYP4C39is expressed in the hepatopancreas,which suggests it may have a role in ecdysteroid metabolism by peripheral tissues[59].Ecdysteroids secreted by the YO are converted to20-hydroxyecdysone(20E)and related compounds by peripheral tissues,such as gonad,hindgut,abdominal ganglia,eyestalk ganglia,hepatopancreas,antennal gland,and epidermis(Fig.2) [38,61–66].YOs cannot convert3DE to ecdysone or ecdysone to20E[31,43,61].In peripheral tissues,ecdysone is hydroxy-lated at C20,probably by Shd,to produce20E[38,40,41,62–64]. A20-hydroxylase activity in the hepatopancreas of the blackback land crab(Gecarcinus lateralis)requires NADPH,is inhibited by metyrapone(an inhibitor of cytochrome P450enzymes),and is associated with the mitochondrial fraction[62].A3␤-reductase converts3DE to ecdysone,which is hydroxylated at C20,to produce 20E[32,38,45,61,63].In M.mercenaria,3␤-reductase in peripheral tissues converts3D25dE to25dE,which is then converted to PA [32].In C.maenas,25dE is converted to PA by a20-hydroxylase in the testis[34,40,41].PA can be hydroxylated at C25or C26 to produce20E or inokosterone,respectively[67].In crayfish(O. limosus),abdominal ganglia convert3DE to ecdysone,20E,and 3D20E[63].Antennal glands of crayfish express an aldoketore-ductase,but its precise function is unknown;it may catalyze 3␤-reduction or may have an osmoregulatory role by converting D-glucose to sorbitol[68].These data indicate that peripheral tissues have3␤-reductase,25-hydroxylase,and20-hydroxylase activities, which can convert products secreted by the YO to20E and related compounds.3.Hemolymph ecdysteroids over the molt cycleTotal ecdysteroid titers in the hemolymph vary over the molt cycle.In general,ecdysteroids are low during intermolt and postmolt;during premolt,concentrations rise and reach a peak shortly before molting(ecdysis)in a variety of crustacean species [2,5–7,46,62,69–89].A precipitous drop in hemolymph ecdys-teroids triggers the shedding of the exoskeleton[90].Eyestalk ablation,which removes the primary source of inhibitory neu-ropeptides(e.g.,MIH),activates the YO and increases hemolymph ecdysteroid levels[1,2,21,23,70,79,86,91,92].In addition to the peak in hemolymph titers at the end of the premolt stage,there are smaller peaks during postmolt and early premolt stages,which may have physiological functions[30,48,93–95].For species with terminal molts,the YOs degenerate and ecdysteroids remain at200 D.L.Mykles/Journal of Steroid Biochemistry&Molecular Biology127 (2011) 196–203low concentrations in the hemolymph,even after eyestalk ablation [2,96].The major ecdysteroids identified in the hemolymph of decapod crustaceans are ecdysone,20E,3D20E,and PA, but the specific compounds and their levels vary between species,developmental stage,molt stage,and season [32,44,48,49,61,64,66,67,70,78,81,82,87,93,97].In stone crabs (M.mercenaria)that have been eyestalk ablated to activate the YO, 20E,3D20E,and PA are present in about equal amounts;a fourth large peak eluting from a reverse-phase column was not identified [32].Infiddler crab(U.pugilator)induced to molt by eyestalk ablation,there are two transitory peaks of hemolymph ecdysteroid that differ in the relative titers of ecdysteroids.Peak I,which occurs at early premolt,has a higher ratio of ecdysone to20E than peak II,which occurs at late premolt[48].Eyestalk ablation alters the composition of ecdysteroids circulating in the hemolymph, but the effect differs between species.In blue crabs(C.sapidus) at late premolt,PA is the major ecdysteroid in intact animals, whereas20E is the major ecdysteroid in eyestalk-ablated animals [70].In U.pugilator,the PA:20E ratio in the hemolymph is higher in animals induced to molt by eyestalk ablation than in animals induced to molt by multiple leg autotomy[49].In Kuruma prawn (Penaeus japonicus),20E and PA are the major ecdysteroids during the postmolt and intermolt stages,while20E alone is the major ecdysteroid during early and late premolt stages[87].In C.maenas, ecdysone and20E are detected at low levels in the hemolymph of intermolt animals,whereas the PA level is higher than the20E level in the hemolymph of premolt animals[34,67,78].At late premolt(stage D3),the titers of PA in the hemolymph decline more rapidly than those of ecdysone and20E[78].This corresponds to a change in the relative amounts of ecdysone and25dE,a precursor to PA,secreted by the YO between intermolt and premolt animals; YOs from premolt animals secrete greater amounts of25dE than ecdysone than YOs from intermolt animals[40,41].This appears to depend on the activities of enzymes at the branching points (Fig.2).For example,in rock crab and crayfish YOs,an increase in3␤-reductase activity would shift production and secretion from3DE to ecdysone[31].In green andfiddler crabs,an increase in25-hydroxylase activity would shift secretion from25dE to ecdysone[31].Ecdysteroid composition can be affected by developmental stage.During the last three molts,blue crabs(C.sapidus)transi-tion through juvenile,prepubertal,and adult stages.PA is the major hemolymph ecdysteroid at all three stages.However,the titers of PA in juveniles are significantly higher than and the titers of20E significantly lower than the titers in prepubertal and adult stages [70].In juvenile C.sapidus,eyestalk ablation increases hemolymph ecdysteroid titers,but there is no peak in ecdysteroids prior to ecd-ysis and titers during postmolt remain elevated compared to intact animals[70].These data indicate that there are stage-specific dif-ferences in ecdysteroid metabolism,but the functional significance of these changes remains to be investigated.4.Ecdysteroid metabolism and excretion20E and PA are the major active ecdysteroids circulating in the hemolymph of decapod crustaceans.Inactivation involves conver-sion to more polar metabolites and/or formation of conjugates, which are excreted in the urine or eliminated in the feces.Thus,the two major organs responsible for removing ecdysteroids from the hemolymph are the antennal gland and hepatopancreas(midgut gland)in decapods.The diversity of inactivation pathways in crustaceans is reminiscent to those used by insects to detoxify ecdysteroids ingested from plants(see[98]for review).The pri-mary site for excretion of ecdysteroids is the antennal gland.In lobster(Homarus americanus),between81%and96%of excreted ecdysteroids is in the urine,depending on the molt stage;the remainder is in the feces[66,97].In crayfish(O.limosus),there is a preferential excretion of ecdysone over20E.About two-thirds of the[3H]ecdysone injected into the hemolymph appears in the water after1h[99].In contrast,most of the[3H]20E injected into the hemolymph remains in the hemolymph,with less than5%of the[3H]20E appearing in the water after1h[99].This suggests that selective excretion of unmetabolized ecdysone by the antennal gland keeps hemolymph ecdysone titers low.Conversion of ecdysteroids to more polar compounds involves two modifications of the side chain at the#26carbon:hydrox-ylation and oxidation.In insects,20E is inactivated by a cytochrome P45026-hydroxylase[100,101].In decapod crus-taceans,a26-hydroxylase activity in various tissues converts20E to20,26-dihydroxyecdysone(20,26E)and PA to inokosterone(25-deoxy-20,26-dihydroxyecdysone or25d20,26E)[63,65–67,97]. Oxidation at the C26forms ecdysonoic acids(EAs).For example, 20E and PA are metabolized to20-hydroxyecdysonoic acid(20EA) and25-deoxy-20-hydroxyecdysonoic acid(25d20EA),respec-tively,and are excreted in the urine[65–67,97,102].Ecdysteroids can also be converted to their3␣-hydroxy epimers by periph-eral tissues.In crayfish(P.clarkii),a3␣-reductase activity in the epidermis converts ecdysone and20E to3␣-hydroxyecdysone and3␣,20-hydroxyecdysone,respectively,which are selectively excreted[61].Various tissues can convert ecdysteroids and their metabolites to highly polar(HP)conjugates,which can be excreted in the urine[61,63,65,66,97].The levels of HP conjugates vary over the molt cycle and can at times be the predominant ecdysteroid in the hemolymph[61,77,82,87,88,93].In H.americanus,the rapid drop in ecdysteroids at the end of premolt is associated with an increase in HP metabolites in the hemolymph and excretion in the urine[93,97].Using[3H]ecdysone as a tracer,a greater proportion (about75%after72h)is converted into HP conjugates in postmolt (stage A)and intermolt(stage C)lobsters than is converted in early premolt(stages D0and D1)lobsters(about25%after72h)[66]. The conversion by late premolt(stage D2)lobsters increases after injection and reaches early premolt levels by96h as animals tran-sition through the late premolt ecdysteroid peak[66].In C.maenas, intermolt and premolt animals differ in the metabolism of[3H]PA injected into the hemolymph.Forty-eight hours after injection into intermolt animals,the major metabolites were conjugates and 20EA,whereas24h after injection into premolt animals,the major metabolites were conjugates only[67].Enzymatic hydrolysis with snail sulfatase or porcine liver esterase is used to analyze the com-position of conjugates[66,93].HP conjugates in the hemolymph contain various ecdysteroids and metabolites usually in proportion to their hemolymph concentrations[93,97].This indicates that the modifications are generally nonspecific.However,HP conjugates in the urine contain relatively high proportions of polar metabo-lites,such as20,26E,3␣-hydroxy compounds,and ecdysonoic acids [61,66,97].In addition,excretion rates of H.americanus are higher in intermolt and late premolt(D2)stages than early premolt(D0 and D1)stages[66].These data suggest that the conversion of ecdysteroids to inactive polar metabolites and their preferential excretion by the antennal gland can determine the ecdysteroid titers in the hemolymph,especially at the end of premolt when titers drop precipitously.The hepatopancreas is the primary site for the production of apolar conjugates(perhaps fatty acyl esters),which are then elim-inated in the feces[65,66,99].These conjugates can be formed from ecdysteroids in the hemolymph[63,65,66,84,97]or from ecdysteroids ingested with food[97].When lobsters were fed [3H]ecdysone,less than0.4%of the radioactivity appeared in the hemolymph and urine;essentially all of the[3H]ecdysone was in the form of apolar conjugates in the feces[97].The amounts of apo-。

第01节课 复习题一、经典物理学有几个组成部分？答：牛顿力学，经典电磁理论，经典热力学，经典统计物理学二、电磁辐射是一种波，都有其最小单位能量ε。

ε与电磁辐射的频率υ 是什么关系？1电子伏特(eV)的能量等同于多少焦耳(J)？ 答：ε=υh ; 1 eV ＝ 1.6022 × 10−19 J三、根据光子学说，光子的动量计算公式hp =λ是如何得来的？辐射频率为99.8MHz 和1.6 GHz 的光量子的动量是多少？ 答：2ε=ν=h mc ，所以2ν=h m c ，因此，h hp mc c ν===λ辐射频率为99.8 MHz 和1.6 GHz 的光量子的动量分别为：346134181h h h 6.62610J s 99.810s p 2.20510J s m c /c 2.99910m s -----ν⨯⋅⨯⨯=====⨯⋅⋅λν⨯⋅ 349133181h h h 6.62610J s 1.610s p 3.53510J s m c /c 2.99910m s-----ν⨯⋅⨯⨯=====⨯⋅⋅λν⨯⋅ 四、Einstein 的光电效应公式是什么？其中每一项具有什么物理意义？ 答：201h h mv 2ν=ν+，第一项是入射辐射光量子的能量，第二项是材料的电子脱出功，第三项是产生的光电子的动能。

五、以波长为540 nm 的光去照射一电子脱出功为J 10621.219-⨯的材料表面，计算被激发出的光生 电子的动能和运动速率。

解：因为 v 0E h h +ν=ν 所以，v e E W c h +=λs J 10626.634⋅⨯-m10540s m 10998.2918--⨯⋅⨯⨯=J 10621.219-⨯+ E v 所以，J 10621.2J 10679.3E 1919v --⨯-⨯=J 10058.119-⨯= 由于2v mv 21E =所以，153119v s m 10819.4kg10110.9J10058.12m E 2v ---⋅⨯=⨯⨯⨯== 六、Einstein 的光子学说的主要内容是什么？ 答：1. 光是一束光子流，每一种频率的光的能量都有一个最小单位，称为光子，光子的能量与光子的频率成正比，即，h ε=ν2. 光子不但有能量，还有质量(m)，但光子的静止质量为03. 光子具有一定的动量(p)，其动量为p h /=λ4. 光的强度取决于单位体积内光子的数目，即，光子密度七、国际电工委员会规定，家用微波炉的微波频率统一使用2450 MHz ，而大型工业微波炉频率为915 MHz ，其波长是多少？如果把微波看作是粒子，其动量是多少？ 答：2450 MHz 的辐射波长为：81612.99910m s c /0.122m 245010s --⨯⋅λ=ν==⨯ 915 MHz 的辐射波长为：81612.99910m s c /0.328m 91510s--⨯⋅λ=ν==⨯ 辐射频率为2450 MHz 的辐射量子的动量为：34331h 6.62610J s p 5.41310J s m 0.1224m---⨯⋅===⨯⋅⋅λ 辐射频率为915 MHz 的辐射量子的动量为：34331h 6.62610J sp 2.02110J s m 0.3278m---⨯⋅===⨯⋅⋅λ 八、黑龙江交通台的发射和接收频率为99.8 MHz (FM, 调频)，那么其粒子的波长、波数和动量各是多少？波长为：81612.99910m s c /3.005m 99.810s --⨯⋅λ=ν==⨯ 波数为：1110.333m 3.005m-ν===λ 动量为：34341h 6.62610J sp 2.20510J s m 3.005m---⨯⋅===⨯⋅⋅λ九、镍金属的功函为5.0 eV, 计算镍金属的临阈频率和临阈波长。