紫色色杆菌苯丙氨酸羟化酶的异源表达及重组酶学性质研究

来源于紫色色杆菌(Chromobacterium violaceum)的苯丙氨酸羟化酶结构简单,性质更接近于人的苯丙氨酸羟化酶,具有潜在的医药应用价值。从紫色色杆菌基因组中克隆得到苯丙氨酸羟化酶基因pah。构建重组表达载体pET24a-pah,并在Escherichia coli BL21(DE3)中实现高效表达。离子层析纯化后,重组蛋白比酶活高达503.2 U/mg。酶学性质研究显示,该重组酶的最适温度为40℃左右,50℃时PAH的半衰期为15 min;最适pH在7.5左右,在pH6-8范围内较稳定。37℃,pH7.5条件下,Km值为1.5 mmol/L,Vmax为0.5 mmol/min,kcat为5.05/s,催化效率kcat/Km为3.37 L/mmol·s。     

2型猪链球菌磷酸甘油酸激酶基因的克隆表达及酶活性测定

目的:克隆表达2型猪链球菌中磷酸甘油酸激酶(PGK)并对其酶学特性进行测定。方法:采用PCR方法从05ZYH33基因组中扩增出pgk片段,构建重组表达质粒p ET28a:pgk,经双酶切及测序验证正确的质粒转化入E.coli BL21(DE3)中进行IPTG诱导表达,重组PGK蛋白经SDSPAGE和质谱鉴定并测定其酶学活性。结果:PGK在大肠杆菌中可溶性表达,纯化后得到约43k Da的重组PGK蛋白,其酶促反应最适温度为25℃,最适pH为7.5,2型猪链球菌PGK的酶活性为75U/ml,PGK相对于3-PGA的Km值为1.744mmol/L,Vmax为0.143mmol/(L·min),相对于ATP的Km值为2.266mmol/L,Vmax为0.318mmol/(L·min)。结论:利用原核表达系统成功地表达了2型猪链球菌中的PGK,并获得了活性较好的重组PGK,酶学检测发现纯化的PGK具有良好的体外活性,为进一步研究该病在2型猪链球菌致病及代谢机制奠定了基础。     

三磷酸腺苷对蟾蜍交感神经节细胞的作用及机制分析

目的　观察ATP所引起的蟾蜍椎旁交感神经节细胞电位变化和有关因素的影响 ,以探讨ATP在神经节内的作用及其机制。方法　采用细胞外微电极技术记录离体灌流神经节电位。结果　外源性ATP(2 0 0 μmol L)可引起去极化 (n =1 1 0 ) ,超极化 (n =33) ,以及去极后伴随一超极过程的双相反应 (n =1 2 )。P2 嘌呤受体拮抗剂ci bacronblue 3GA(30 0 μmol/L)和奎尼丁 (30 0 μmol/L) ,均可抑制ATP所致去极反应 ,其幅值分别减小 (2 4 .2± 1 7.5 ) %(n =1 8,P <0 .0 1 )和 (32 .5± 1 1 .5 ) % (n =2 1 ,P <0 .0 1 )。P1 嘌呤受体拮抗剂氨茶碱 (2 0 0 μmol L) ,可抑制ATP所致超极反应 ,幅值减小 (6 5 .0± 2 2 .9) % (n =9,P <0 .0 1 )。在无钠溶液中 ,ATP的去极幅值变化为 (1 3.6± 1 7.5 ) % (n =1 0 ,P >0 .0 5 ) ,无统计学意义。在无钙溶液中或同时加用EDTA(1mol L)以去除溶液的Ca2 ,可使ATP所致去极幅值减小 (2 3.6± 1 8.3) % (n =1 5 ,P <0 .0 1 )。电压依赖性钾通道阻断剂 4—氨基吡啶 (3mmol L)和ATP敏感性钾通道阻断剂格列苯脲 (1 0 0mol L) ,均可可抑制ATP所致超极反应 ,其幅值分别减小 (6 4 .5± 2 1 .9) % (n =1 1 ,P <0 .0 1 )和(6 6 .4± 2 2 .4 ) % (n =6 ,P <0 .0 1 )。前列腺素合成酶抑制剂吲     

不吸水链霉菌ZB01 cyp107z基因的克隆及原核表达纯化

【目的】克隆不吸水链霉菌ZB01中的cyp107z基因,在E.coli中异源表达纯化,测定重组酶蛋白的酶动力学参数,为该基因的进一步研究奠定基础。【方法】根据cyp基因保守区序列设计引物,扩增不吸水链霉菌ZB01基因组中cyp107z基因的部分序列,通过染色体步移技术获取全长基因。利用pET28a表达载体构建该基因原核表达载体并于E.coli中诱导表达,以Ni-NTA亲和层析纯化表达出的重组蛋白。以阿维菌素为底物,构建重组蛋白体外催化体系,通过测定体系中NADPH的消耗,计算重组蛋白催化阿维菌素反应的酶动力学参数。【结果】从不吸水链霉菌ZB01基因组扩增出一条cyp107z基因同源基因,全长1290 bp,编码429个氨基酸残基,命名为cyp107z13,在E.coli中诱导表达了该重组酶蛋白,纯化后的重组酶蛋白催化阿维菌素的Km值为1.4μmol/L,Vmax为0.041μmol/min.mg,kcat为0.033 s-1。【结论】从不吸水链霉菌ZB01中克隆到cyp107z13基因,异源表达的CYP107Z13重组蛋白能够催化以阿维菌素为底物的氧化反应。     

肌球蛋白轻链激酶非激酶活性调节磷酸化肌球蛋白ATP酶活性及肌丝运动

肌球蛋白轻链激酶(myosin light chain kinase,MLCK)具有激酶和非激酶活性,在平滑肌收缩过程中起着关键酶调控的作用.为进一步阐明MLCK非激酶活性在平滑肌收缩过程中的调节作用,利用已删除部分激酶区域的MLCK重组体(pGEXF6.5)在大肠杆菌中进行表达,采用亲和层析技术纯化表达的MLCK片段,应用EnzChek磷分析试剂盒检测MLCK片段对磷酸化肌球蛋白、水解重酶解肌球蛋白(heavymeromyosin,HMM)及肌球蛋白亚片段1(subfragmentl,S1)ATP酶活性的影响,体外检测MLCK片段对肌动蛋白肌丝运动的调节.研究结果显示,pGEX-F6.5重组表达载体在大肠杆菌中以可溶性GST融合蛋白的形式表达.该融合蛋白经Glutathione-Sepharose4B纯化、SDS-PAGE鉴定得到较纯的单一表达条带.纯化的MLCK片段对磷酸化肌球蛋白、HMM和S1的ATP酶活性均有明显激活作用.MLCK片段激活磷酸化肌球蛋白ATP酶活性为:Vmax=(19.426±1.669)倍;Km=(0.486±0.106)μmol/L,MLCK片段对磷酸化HMM和S1的ATP酶活性也有相似的刺激作用.体外肌丝运动研究表明,随着MLCK片段浓度的增加,磷酸化肌球蛋白与肌动蛋白结合的数量不断增加,肌丝运动的速度也随之增加.上述结果表明,MLCK的C端非激酶活性具有调节磷酸化的肌球蛋白ATP酶活性及肌丝运动的作用.     

肠膜明串珠菌蔗糖磷酸化酶的酶学表征及在催化合成α-熊果苷中的应用

将来源于肠膜明串珠菌Leuconostoc mesenteroides ATCC 12291的蔗糖磷酸化酶(Sucrose phosphorylase,SPase)基因进行密码子优化后将其插入到pET-28a中构建表达载体pET-28a-spase,诱导大肠杆菌Escherichia coli BL21(DE3)/pET-28a-spase表达制得SPase粗酶液,将重组SPase纯化后进行酶学表征。结果表明,重组SPase的比酶活为213.98 U/mg,纯化倍数为1.47倍,酶活回收率达87.80%。该酶最适温度为45℃,最适pH为6.5,该酶对蔗糖的Km为128.8 mmol/L,Vmax为2.167μmol/(mL·min),kcat为39 237.86 min-1,利用重组SPase催化氢醌合成α-熊果苷,最优条件为:氢醌添加量为40 g/L,蔗糖/氢醌的摩尔比为5:1,重组SPase 250 U/mL。在25 mmol/L的吗啉乙磺酸(MES)缓冲液(pH 7.0)中,反应温度30℃,避光反应24 h后终止反应,再用500 U/mL的糖化酶40℃处理2.5 h。α-熊果苷产量达98 g/L,氢醌的转化率接近99%。综上所述,文中克隆并研究了重组SPase,并建立了其在α-熊果苷生产中的应用。     

阿维菌素起始酰基转移酶的底物特异性

[背景]阿维菌素起始酰基转移酶(AveAT0)能够以2-甲基丁酰-辅酶A (coenzyme A,CoA)和异丁酰-CoA作为起始单元分别合成"a"系列或"b"系列的阿维菌素。[目的]探究AveAT0对两种底物的偏好性并进行改造。[方法]通过与识别不同底物的起始酰基转移酶(loading acyltransferases,AT0s)进行序列比对,找到AveAT0底物结合重要的氨基酸,利用活性位点定点突变的方法得到对底物偏好性改变的特定突变体。以2-甲基丁酰-CoA、异丁酰-CoA的类似物2-甲基丁酰-N-乙酰半胱氨(N-acetylcysteamine,SNAC)和异丁酰-SNAC为底物,用Ellman测试法检测释放SNAC的游离巯基(sulfhydryl,SH),测定AveAT0及其突变体的动力学常数,以此表征AveAT0及其突变体的底物偏好性。[结果]AveAT0对2-甲基丁酰SNAC的Km值为0.4 mmol/L,kcat值为14.1 min^-1,kcat/Km为32.1 L/(mmol·min);对异丁酰-SNAC的Km值为0.8 mmol/L,kcat值为6.4 min^-1,kcat/Km为7.5 L/(mmol·min)。选定的突变位点为V224M、Q149L、L121M。按顺序累积突变后发现三突变株AveAT0 V224M/Q149L/L121M对两个底物的偏好性区别最大,对2-甲基丁酰SNAC的Km值为0.8 mmol/L,kcat值为5.4 min^-1,kcat/Km为6.9 L/(mmol·min);对异丁酰-SNAC的kcat/Km为0.1 L/(mmol·min)。[结论]研究发现了AveAT0识别底物过程中的关键氨基酸,为改造阿维菌素聚酮合酶酰基转移酶提供了依据。     

山奈酚抑制蛋白激酶CK2活性

研究体外以及HL-60细胞内山奈酚对蛋白激酶CK2的抑制作用及机制. 通过测定药物作用后转移到CK2底物上的[γ-32P]ATP的32P的放射性活度, 探讨山奈酚对重组人CK2全酶以及细胞内CK2活性的影响; 采用多重RT-PCR检测CK2α、α' 和 β亚基的mRNA表达水平; 通过 Lineweaver-Burk作图法,分析CK2的酶动力学机制.山奈酚能显著抑制重组人CK2活性（IC50 = 1.88 μmol/L）和HL-60细胞内的CK2活性, 对细胞内CK2的作用效果强于阳性对照四溴-2-氮杂苯并咪唑(TBB). 山奈酚作用2h,对CK2各亚基的mRNA表达水平均没有影响. 山奈酚对重组人CK2的酶动力学分析表明, 山奈酚与ATP(Ki = 1.14 μmol/L)及酪蛋白(Ki = 1.03 μmol/L)均呈非竞争性抑制作用. 结果提示, 山奈酚是一种有效的蛋白激酶CK2的抑制剂, 其作用机制可能与其阻碍CK2与ATP以及底物的结合有关.     

ATP合成菌株的构建及用于联合生产S-腺苷甲硫氨酸

为降低S-腺苷甲硫氨酸的生产成本,构建了同时表达腺苷激酶、腺苷酸激酶和乙酸激酶3种酶的重组大肠杆菌菌株用于ATP的合成,并对ATP的转化条件进行了优化,优化后的反应体系为:腺苷30 mmol/L,乙酰磷酸二锂盐135 mmol/L,硫酸镁5 mmol/L,硼砂50 mmol/L,菌体2 g/L(湿重),反应液初始pH7.5,反应温度为35℃,反应时间为3 h,反应转化率可以达到99%以上。按照上述反应体系进行5 L放大,反应结束后再投入65 mmol/L D,L-甲硫氨酸和50 g/L(湿重)表达腺苷甲硫氨酸合成酶的重组大肠杆菌菌体,并补加15 mmol/L硫酸镁,转化18 h S-腺苷甲硫酸浓度能达到8.7 g/L,转化率达到72.5%。     

D-乳酸生产菌菊糖芽孢乳杆菌来源的D-乳酸脱氢酶同工酶

【目的】菊糖芽孢乳杆菌(Sporolactobacillus inulinus)作为典型的同型发酵产D-乳酸的优势菌株,能够高效生产高纯度的D-乳酸。该菌株发酵受到多方面环境因素影响。糖代谢的关键酶例如葡萄糖激酶、磷酸果糖激酶、丙酮酸激酶以及乳酸脱氢酶均为由葡萄糖代谢成为乳酸的关键酶,该菌中相关代谢酶的研究是发酵调控至关重要的基础。分析S.inulinus的基因组表明有3个推测为D-乳酸脱氢酶的基因,其中已有报道研究了1个双功能蛋白[bifunctional protein(BP)]。本研究分别克隆并解析了另2个D-乳酸脱氢酶同工酶的性质。【方法】本研究以S.inulinus Y2-8基因组DNA为模板,克隆得到2个D-ldh基因(dldh、dhdh),经测序分别为D-乳酸脱氢酶[D-lactic acid dehydrogenase(DLDH)]和D-羟基酸脱氢酶[D-isomer specific 2-hydroxyacid dehydrogenase(DHDH)]的基因。构建的重组菌表达蛋白DLDH,DHDH均具有催化丙酮酸生成D-乳酸的功能。【结果】重组菌表达的蛋白经镍柱亲和层析达到电泳纯。SDS-PAGE分析表明DLDH的表观分子量为37 k Da,DHDH的表观分子量为39 k Da。此外,DLDH以丙酮酸为底物时Km值为(0.58±0.04)mmol/L,对底物有较高的亲和力,最适反应温度为35°C,最适p H为6.5;而DHDH以丙酮酸为底物时Km值为(1.70±0.08)mmol/L最适反应温度为30°C,最适p H为7.5。另有报道的BP以丙酮酸为底物时Km值为(3.40±0.02)mmol/L,最适反应温度为30°C,最适p H为5.5。【结论】根据对底物丙酮酸的亲和力,最适温度及最适p H,推测DLDH是乳酸发酵中产D-乳酸的主导催化剂。结合相关酶学性质的分析可为今后的发酵调控提供理论依据。     

Simultaneous measurement of the trace elements Al, As, B, Be, Cd, Co, Cu, Fe, Li, Mn, Mo, Ni, Rb, Se, Sr, and Zn in human serum and their reference ranges by ICP-MS

The goal of this article was to establish reference ranges of the concentration of trace elements in human serum and to compare these results with those reported by other authors. We describe the sample preparation and measurement conditions that allow the rapid, precise, and accurate determination of Al, As, B, Be, Cd, Co, Cu, Fe, Li, Mn, Mo, Ni, Rb, Se, Sr, and Zn in human serum samples (n=110) by inductively coupled plasma-mass spectrometry (ICP-MS). Accuracy and precision were determined by analyzing three reconstituted reference serum samples by comparison with other methods and by the standard addition procedure. The advantages of the ICP-MS method include short time of analysis of the elements mentioned, low detection limit, high precision, and high accuracy. Disadventages include a high risk of contamination due to the presence of some of the elements of interest in the environment, the relatively delicate sample handling, and the high cost of the equipment.     

Distribution of N,P, K,Ca, Mg,S, Zn,Fe, Mn and Cu in groundnut

Summary Concentration of N, P, K, Ca, Mg and S in summer groundnut crop was higher than in kharif while Zn, Fe, Mn and Cu contents were higher in summer crop. Kernel's N, P and Zn; Leaflet's Ca and Mn; Stem's K and Fe; Root's S and Cu and Petiole's Mg contents were highest. Shell's N, P, K, Mg, S, Zn and Cu; Kernel's Ca, Fe and Mn contents were the least. N, P, K, S, Zn and Cu concentrations decreased linearly as the crop grew. Ca, Mg, Fe and Mn concentrations did not display any distinct pattern. Ca concentration was positively correlated with pod yield in both the seasons.     

Crystal structure, detonation performance, and thermal stability of a new polynitro cage compound: 2, 4, 6, 8, 10, 12, 13, 14, 15-nonanitro-2, 4, 6, 8, 10, 12, 13, 14, 15-nonaazaheptacyclo [5.5.1.13, 11. 15, 9] pentadecane

A new polynitro cage compound 2, 4, 6, 8, 10, 12, 13, 14, 15-nonanitro-2, 4, 6, 8, 10, 12, 13, 14, 15-nonaazaheptcyclo [5.5.1.1(3,11).1(5,9)] pentadecane (NNNAHP) was designed in the present work. Its molecular structure was optimized at the B3LYP/6-31 G(d,p) level of density functional theory (DFT) and crystal structure was predicted using the Compass and Dreiding force fields and refined by DFT GGA-RPBE method. The obtained crystal structure of NNNAHP belongs to the P-1 space group and the lattice parameters are a = 9.99 ?, b = 10.78 ?, c = 9.99 ?, α = 90.01°, β = 120.01°, γ = 90.00°, and Z = 2, respectively. Based on the optimized crystal structure, the band gap, density of state, thermodynamic properties, infrared spectrum, strain energy, detonation characteristics, and thermal stability were predicted. Calculation results show that NNNAHP has detonation properties close to those of CL-20 and is a high energy density compound with moderate stability.     

Reference values for the concentrations of As,Cd, Co,Cr, Cu,Fe, I,Hg, Mn,Mo, Ni,Pb, Se,and Zn in selected human tissues and body fluids

This report attempts to formulate reference ranges of elemental concentrations for 15 trace elements in selected human tissues and body fluids. A set of samples consisting of whole blood, blood serum, urine, milk, liver, and hair were chosen and considered for 15 elements of biological significance: As, Cd, Co, Cr, Cu, F, Fe, I, Hg, Mn, Mo, Ni, Pb, Se, and Zn. The results represent wholly or partially data received from 40 countries of the global regions of Africa, Asia, Europe, North, South, and Central America, Australia, and New Zealand. This survey, even if qualitative, has been useful in demonstrating certain trends of trace-element scenarios around the world. It is of course recognized that both diet and environment exert a strong influence on the distribution pattern of several elements, such as As, Cd, Mn, Pb, Se, and Zn. A limited comparison of the available information on soil status of different countries reflected some interesting associations for elements, such as Mn and Zn. Importantly, this study revealed that only a few countries were in a position to identify a reasonable amount of data on samples requested for this project. Regretably, for a number of countries, any dependable data for even such essential elements as Cu, Fe, and Zn were not available. In view of the nutritional importance of many elements, the time is ripe for concerted efforts by intergovernmental agencies to initiate investigations or commission task forces/projects to generate reliable reference data for selected global regions, which sadly lack data of any kind at present.     

Monovalent Cation Permeation through the Connexin40 Gap Junction Channel : Cs,Rb, K,Na, Li,TEA, TMA,TBA, and Effects of Anions Br,Cl, F,Acetate, Aspartate,Glutamate, and NO3

The unitary conductances and permeability sequences of the rat connexin40 (rCx40) gap junction channels to seven monovalent cations and anions were studied in rCx40-transfected neuroblastoma 2A (N2A) cell pairs using the dual whole cell recording technique. Chloride salt cation substitutions (115 mM principal salt) resulted in the following junctional maximal single channel current-voltage relationship slope conductances (γ_j in pS): CsCl (153), RbCl (148), KCl (142), NaCl (115), LiCl (86), TMACl (71), TEACl (63). Reversible block of the rCx40 channel was observed with TBA. Potassium anion salt γ_j are: Kglutamate (160), Kacetate (160), Kaspartate (158), KNO₃ (157), KF (148), KCl (142), and KBr (132). Ion selectivity was verified by measuring reversal potentials for current in rCx40 gap junction channels with asymmetric salt solutions in the two electrodes and using the Goldman-Hodgkin-Katz equation to calculate relative permeabilities. The permeabilities relative to Li⁺ are: Cs⁺ (1.38), Rb⁺ (1.32), K⁺ (1.31), Na⁺ (1.16), TMA⁺ (0.53), TEA⁺ (0.45), TBA⁺ (0.03), Cl⁻ (0.19), glutamate⁻ (0.04), and NO₃− (0.14), assuming that the monovalent anions permeate the channel by forming ion pairs with permeant monovalent cations within the pore thereby causing proportionate decreases in the channel conductance. This hypothesis can account for why the predicted increasing conductances with increasing ion mobilities in an essentially aqueous channel were not observed for anions in the rCx40 channel. The rCx40 effective channel radius is estimated to be 6.6 Å from a theoretical fit of the relationship of relative permeability and cation radius.     

Relations of the Al,B, Ba,Br, Ca,Cl, Cu,Fe, K,Li, Mg,Mn, Na,P, S,Si, Sr,and Zn mass fractions to morphometric parameters in pediatric and nonhyperplastic young adult prostate glands

The variation with age of the 18 trace element mass fractions and some histological characteristics of intact prostate glands of 50 subjects aged 0–30 years was investigated by instrumental neutron activation analysis, inductively coupled plasma atomic emission spectrometry, and a quantitative morphometric analysis. Mean values ± standard error of the mean (M ± SΕΜ) for the mass fractions (in milligrams per kilogram wet tissue) of these trace elements in pre-puberty were: Al 28.5 ± 9.0, B 0.40 ± 0.11, Ba 1.48 ± 0.44, Br 10.5 ± 1.5, Ca 241 ± 30, Cl 3,203 ± 278, Cu 3.51 ± 0.89, Fe 33.7 ± 4.1, K 2,364 ± 145, Li 0.020 ± 0.004, Mg 153 ± 23, Mn 0.46 ± 0.06, Na 2,286 ± 130, P 1,391 ± 100, S 1,698 ± 132, Si 62 ± 11, Sr 0.38 ± 0.08, and Zn 27.6 ± 2.3. During puberty and postpuberty, when there is a significant increase in circulating androgens, the mean values were: Al 7.2 ± 1.4, B 0.21 ± 0.05, Ba 0.25 ± 0.06, Br 5.8 ± 1.0, Ca 433 ± 81, Cl 2,314 ± 201, Cu 1.77 ± 0.13, Fe 20.9 ± 1.6, K 2,585 ± 118, Li 0.0088 ± 0.0014, Mg 232 ± 27, Mn 0.34 ± 0.04, Na 1,875 ± 107, P 1,403 ± 98, S 1,673 ± 73, Si 22.2 ± 3.1, Sr 0.22 ± 0.03, and Zn 93.3 ± 8.9. Mean values (M ± SΕΜ) of percent volumes (%) of the stroma, epithelium and lumen in the prostate before puberty were 73.4 ± 2.6, 20.4 ± 1.7, and 4.45 ± 0.94, respectively, versus 46.5 ± 2.5, 38.5 ± 1.9, and 14.9 ± 1.2 during puberty and postpuberty. This work’s results confirm that the Zn mass fraction in prostate tissue is an androgen-dependent parameter. For the first time it has been demonstrated that the glandular lumen is a main pool of Ca, Mg, and Zn accumulation and that the stroma is a main pool of Al, B, Ba, Br, Cl, Cu, Fe, Mn, Na, and Si accumulation in the normal human prostate, for the age range 0–30 years. It was concluded that the Ca, Mg, and Zn binds tightly within the prostatic fluid, because the volume of glandular lumen reflects the volume of prostatic fluid.     

The Effect of Age and Gender on Al, B, Ba, Ca, Cu, Fe, K, Li, Mg, Mn, Na, P, S, Sr, V, and Zn Contents in Rib Bone of Healthy Humans

The effect of age and gender on major, minor, and trace element contents in the intact rib bone of 80 relatively healthy 15–55-year-old women and men was investigated. Contents or upper limit of contents of 16 chemical elements in the rib bone were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). Mean values (M?±?SΕΜ) for the mass fraction of Ba, Ca, Cu, Fe, K, Li, Mg, Na, P, S, Sr, and Zn (milligram per kilogram of dry bone) were as follows: 2.54?±?0.16, 171,400?±?4,050, 1.35?±?0.22, 140?±?11, 1,874?±?71, 0.049?±?0.011, 2,139?±?38, 5,378?±?88, 75,140?±?1,660, 1,881?±?51, 291?±?20, and 92.8?±?1.5, respectively. The upper limits of contents of Al, B, Mn, and V were <7.20, <0.65, <0.36, and <0.03, respectively. Statistically significant tendency for the Ca, Mg, and P content to decrease with age was found in the human rib bone, regardless of gender. The mass fraction of Fe in the male rib bone increases with age. It was shown that higher Ca, Mg, Na, P, and Sr mass fractions as well as lower Fe content were typical of female ribs as compared to those in male ribs.     

Caprine blood groups. 2. The C,G, H,I, J,K, L,N, and Q systems

Nine blood group systems of goats were identified using 12 caprine reagents produced by absorption of alloimmune antisera. The caprine C blood group system, possibly homologous to the ovine C blood group system, was characterized by two reagents and shown to be controlled by three alleles,C ¹²,C ²⁵, andC ⁻. A more complex blood group system of goats, designated G, was identified using three reagents and shown to be controlled by six codominant alleles (G ^10.19.20,G ^10.19,G ^10.20,G ¹⁰,G ¹⁹,G ²⁰) and a recessive allele (G ⁻). A further seven one-factor two-allelic systems were identified by seven reagents. The nine genetic systems provided exclusion probabilities of 0.479, 0.492, 0.548, and 0.572 in Australian Angora, Dairy, Cashmere, and Texan Angora goat breeds, respectively. This work was supported by a grant from the Australian Stud Book, Alison Road, Randwick, New South Wales 2031, Australia.