Search for organic compounds in the lunar dust from the sea of tranquiblity

A sample of lunar dust was examined for organic compounds. Carbon detected in concentrations of 157 micrograms per gram had a delta(13)C per mil (PDB) value of + 20. Treatment with hydrochloric acid yielded hydrocarbons of low molecular weight, suggesting the presence of carbides. The gas chromatogram of the acylated and esterified derivatives of the hydrolyzate was similar to that obtained for the Pueblito de Allende meteorite. There were no detectable amounts of extractable high-molecular-weight alkanes, aromatic hydrocarbons, isoprenoid hydrocarbons, normal alkanes, fatty acids, amino acids, sugars, or nucleic acid bases. Traces of porphyrins were found, perhaps arising from rocket exhaust materials.     

猪对饲料氨基酸的消化率(综述)

回肠瘘管法是测定猪对饲料氨基酸的消化率的较为准确的方法。本文综述了近些年的报告中用该方法测定的生长猪对小麦、大麦、玉米,高粱、豆饼、菜籽饼、血粉、肉骨粉等饲料氨基酸的表观消化率。几个主要氨基酸的平均表观消化率约为75％。其中,赖氨酸、蛋氨酸、胱氨酸、色氨酸、苏氨酸和异亮氨酸的表观消化率分别为76、82、72、75、71和77％。单个饲料以血粉,酪蛋白、豆饼和小麦中氨基酸的表观消化率较高,有些可高达90％以上;肉骨粉和高粱中氨基酸的表观消化率较低,有些甚至低于50％。文中对影响氨基酸消化率的因素进行了讨论。     

米槁种子主要营养成分分析

为综合开发米槁种子,采用常规方法对其水分、油脂、蛋白质、粗多糖和灰分进行测定,氨基酸自动分析仪测定其氨基酸组分。结果表明:米槁种子中油脂、蛋白质、水分、粗多糖、灰分的含量分别为55.721%、21.352%、9.000%、2.962%和1.408%。共检测出16种常规氨基酸,其中含有7种人体必需氨基酸,占氨基酸总量的36%。米槁种子中氨基酸组分较全,平衡效果好,可对其氨基酸进行开发利用。     

PLANETARY SCIENCE: Enhanced: A Meteorite Falls on Ice

Primitive meteorites provide a glimpse into the early history of our solar system, but some of the most primitive meteorites are also rarely found on Earth. In his Perspective, Grossman explains why the fall of the Tagish Lake meteorite on 18 January 2000 in British Columbia, Canada, was a lucky event for meteorite researchers. The first analysis of the meteorite is reported by Brown et al. Well-preserved organic matter in the meteorite provides a unique opportunity to study the nature and origin of organic matter that may have accreted on early Earth and played a role in the origin of life.     

Allende meteorite: a high-voltage electron petrographic study

Electron-transparent sections of the Allende meteorite, a carbonaceous chondrite, have been prepared by ion-thinning and examined by high-voltage (800-kilovolt) transmission electron microscopy. The matrix crystals, mainly olivine, range in size from approximately 5 to approximately 0.01 micrometers; carbon is present as intergranular films of poorly crystalline graphite. The chondrules exhibit extensive radiation damage, a feature lacking in the matrix. In addition, both chondrules and matrix are undeformed and contain negative crystals; submicroscopic exsolution lamellae are present in pyroxenes. Comparison of the substructure in the Allende meteorite with that in the Parnallee meteorite and in lunar and selected terrestrial rocks leads to the conclusion that chondrule irradiation preceded cold accretion during formation of the solar system and that the meteorite has since been undisturbed.     

The organic content of the Tagish Lake meteorite

The Tagish Lake meteorite fell last year on a frozen lake in Canada and may provide the most pristine material of its kind. Analyses have now shown this carbonaceous chondrite to contain a suite of soluble organic compounds (approximately 100 parts per million) that includes mono- and dicarboxylic acids, dicarboximides, pyridine carboxylic acids, a sulfonic acid, and both aliphatic and aromatic hydrocarbons. The insoluble carbon exhibits exclusive aromatic character, deuterium enrichment, and fullerenes containing "planetary" helium and argon. The findings provide insight into an outcome of early solar chemical evolution that differs from any seen so far in meteorites.     

贵州黔东南3种野生棘蛙肌肉的氨基酸组成与含量

为了解贵州黔东南棘蛙的肌肉营养价值,采用常规氨基酸分析方法测定黔东南棘胸蛙、棘侧蛙和棘腹蛙3种野生棘蛙肌肉的氨基酸组成与含量,并以鸡蛋蛋白质为标准蛋白,以WHO/FAO氨基酸参考模式为标准对其进行氨基酸营养评价。结果表明:黔东南3种野生棘蛙肌肉的氨基酸组成一致,其中含有苏氨酸、缬氨酸、蛋氨酸、异亮氨酸、亮氨酸、苯丙氨酸和赖氨酸7种人体必需氨基酸,非必需氨基酸5种,天冬氨酸、谷氨酸、甘氨酸和丙氨酸4种鲜味氨基酸。棘胸蛙、棘腹蛙和棘侧蛙肌肉中氨基酸总量分别为84.19%、87.43%和86.12%。必需氨基酸含量占总氨基酸含量的比值分别为39.79%、40.07%和39.06%,在蛙科动物中均属于较高水平。3种棘蛙肌肉中,均以谷氨酸的含量最高,天冬氨酸的含量次之,蛋氨酸含量最低。氨基酸评分(AAS)和化学评分(CS)表明,棘蛙肌肉中第一限制性氨基酸为蛋氨酸,第二限制性氨基酸为缬氨酸。必需氨基酸指数(EAAI)显示,棘胸蛙为86.72、棘腹蛙为89.79、棘侧蛙为86.22。综合各项指标分析,贵州黔东南3种野生棘蛙具有较高的经济价值。     

对48个小麦品种营养品质的研究

对４８个小麦品种的１６种氨基酸进行了分析。结果表明，津丰一号，７９５Ｃ＿１－２２１２，＃４４５，品３９，＃４０６和３１０Ｃ＿３－４６个品种具有优良的蛋白质营养品质，尤其是前３个品种，它们均有１３或１４种氨基酸，超过了各氨基酸平均值的１个或２个标准差，可以用作品质育种的高营养品质材料。另外本文还对必需氨基酸、非必需氨基酸和蛋白质３方面的关系进行了讨论。     

人工养殖硬头鳟鱼卵的营养成分分析

[目的]分析硬头鳟鱼卵营养成分,为综合开发硬头鳟鱼卵产品提供理论依据.[方法]以山泉水人工养殖的硬头鳟成熟卵为研究对象,对其常规营养组成、氨基酸及脂肪酸成分、矿物质及维生素含量进行测定,并对其营养品质进行评价.[结果]硬头鳟鱼卵中粗蛋白含量为25.4%,粗脂肪含量为3.6%;包含人体必需氨基酸8种、非必需氨基酸10种,氨基酸总量为24.32%,必需氨基酸含量为10.79%,占氨基酸总量的44.37%,必需氨基酸总量与非必需氨基酸总量比值(移EAA/移NEAA)为79.75%;谷氨酸含量(3.00%)最高,必需氨基酸中除色氨酸外,其余氨基酸评分均高于联合国粮农组织/世界卫生组织(FAO/WHO)标准,第一限制性氨基酸为色氨酸.硬头鳟鱼卵中共检测到饱和脂肪酸3种,不饱和脂肪酸13种,不饱和脂肪酸含量占脂肪酸总量的84.40%;含有多种人体所需的常量矿质元素(Na、K、Mg、P和Ca)、微量矿质元素(Cu、Zn、Fe、Mn和Se)和维生素(VE、VA、VB1和VB2).[结论]硬头鳟鱼卵具有高蛋白、低脂肪的特点,营养全面且品质优良,可作为保健食品进行开发利用.     

The Tagish Lake meteorite: a possible sample from a D-type asteroid

A new type of carbonaceous chondrite, the Tagish Lake meteorite, exhibits a reflectance spectrum similar to spectra observed from the D-type asteroids, which are relatively abundant in the outer solar system beyond the main asteroid belt and have been inferred to be more primitive than any known meteorite. Until the Tagish Lake fall, these asteroids had no analog in the meteorite collections. The Tagish Lake meteorite is a carbon-rich (4 to 5 weight %), aqueously altered carbonaceous chondrite and contains high concentrations of presolar grains and carbonate minerals, which is consistent with the expectation that the D-type asteroids were originally made of primitive materials and did not experience any extensive heating.     

安徽省主栽食用菌氨基酸含量的研究

对安徽省主栽食用菌氨基酸含量进行了测定,发现几种食用菌的氨基酸种类齐全,必需氨基酸占总量的分别是:香菇21.9%、杏鲍菇19.19%、白灵菇6.0%、金针菇4.13%。菌盖和菌柄中17种氨基酸均有,其中8种氨基酸是人体必需的,且菌盖高于菌柄。     

雷竹不同栽培类型竹笋的蛋白质组成

雷竹19个栽培类型及2信近缘种竹笋的蛋白质组成分析的结果表明：雷竹不同栽培类型及其近缘种竹笋蛋白质的水解氨基酸种类相同，但占干质量的百分比有所差异；从氨基酸总量，必需氨基酸及各种氨基酸占干质量的百分比来看，安微雷竹，安徽雷竹，安徽早竹，金华雷竹和余姚雷竹明显高于其他竹种；弯秆雷竹明显较低，其他栽培类型和2个近缘种之间差异不显著。表1参5     

金针菇深层发酵的研究──Ⅰ．金针菇发酵滤液游离氨基酸的分析

金针菇深层发酵滤液中游离的必需氨基酸占游离氨基酸总量的８０％左右．主要积累的氨基酸为赖氨酸、苯丙氨酸、缬氨酸、蛋氨酸、亮氨酸和精氨酸等．氨基酸的积累情况可归纳为３个类型：第１型为苯丙氨酸＞缬氨酸＞赖氨酸＞蛋氨酸．第２型为赖氨酸＞蛋氨酸＞苯丙氨酸＞缬氨酸．第３型为亮氨酸＞缬氨酸＞赖氨酸＞蛋氨酸．３个类型的共同特点是赖氨酸始终是大量积累的主要氨基酸之一以及必需氨基酸所占的百分比都很高，差异仅在个别氨基酸积累量的多少上．对这种差异的原因进行初步探讨发现：（ＮＨ４）２ＳＯ４浓度和黄豆粉作氮源影响游离氨基酸的总产量和必需氨基酸所占的百分比，而不影响高含量氨基酸的种类．ＰＯ４３－的浓度不同对其差异没有影响．     

多肽和蛋白质的人工合成评述

多肽和蛋白质的人工合成,就是多个氨基酸在一定的条件下通过肽键形成多肽链。氨基酸是合成多肽和蛋白质的原料。在合成前各个氨基酸都必须经过基团保护、氨基和羧基的活化处理,然后经接肽,去除保护基,最后形成多肽链。本文对目前国内外常用的液相合成法和固相合成法的原理和步骤进行了简要的评述。     

Circular polarization in star- formation regions: implications for biomolecular homochirality

Strong infrared circular polarization resulting from dust scattering in reflection nebulae in the Orion OMC-1 star-formation region has been observed. Circular polarization at shorter wavelengths might have been important in inducing chiral asymmetry in interstellar organic molecules that could be subsequently delivered to the early Earth by comets, interplanetary dust particles, or meteors. This could account for the excess of L-amino acids found in the Murchison meteorite and could explain the origin of the homochirality of biological molecules.     

从江腊香猪肉挥发性风味物质检测及前体成分分析

采用SPME-GC/MS和HPLC分别对从江腊香猪产品的挥发性风味物质和氨基酸组成进行了鉴定分析,并用PDMS针头进行固相微萃取,热解析后进行质谱分析。结果表明:腊香猪精瘦肉中具有90种挥发性成分,列前10位化合物次序是:己酸乙酯、乙醇、戊酸、四甲基吡嗪、3-羟基-2-丁酮、柠檬精油、2,3-丁二醇、苯乙酮、醋酸和丁基羟基甲苯,在所有检出的化合物中,酸类占13.46%,醇类占18.93%,酯类占18.3%,醛类占4.21%。腊香猪精瘦肉经水解氨基酸分析,所含的17种氨基酸中,谷氨酸含量最高(4.43%),必需氨基酸总量为12.14%,鲜味氨基酸总量为12.23%,蛋白质总量为27.71%。     

雪山草鸡氨基酸组成与营养价值研究

[目的]评价雪山草鸡的营养价值。[方法]以雪山草鸡为材料,对各种氨基酸的含量及组成进行分析,并评价其营养价值。[结果]雪山草鸡肌肉中氨基酸含量占蛋白质含量的95.34%,且种类齐全,8种人体必需氨基酸的含量达1.096 g/kg。鲜味氨基酸、甜味氨基酸和芳香族类氨基酸占总氨基酸的质量分数分别为24.97%、17.86%和7.07%,各种人体必需氨基酸种类齐全且比例均衡,比值系数分(SRC)为76.91。在各种人体必需氨基酸中,第一限制氨基酸为甲硫氨酸+半胱氨酸。[结论]该研究可为雪山草鸡进一步开发利用提供科学依据。     

苜蓿不同部位的氨基酸组成及含量分析

[目的]为苜蓿的深度开发利用提供理论依据。[方法]利用氨基酸自动分析仪测定分析苜蓿的茎、叶和种子的氨基酸成分和含量。[结果]结果表明,苜蓿中氨基酸含量丰富,叶和茎中含有18种氨基酸,种子含有17种氨基酸。不同苜蓿品种间,同一品种不同部位间氨基酸含量差异较大。苜蓿叶片、茎和种子中氨基酸含量占干重比例分别为30.43%、24.44%和18.31%。必需氨基酸和非必需氨基酸比较分析结果表明,苜蓿叶片具有较高的营养价值。[结论]苜蓿具有更高的营养价值和开发利用价值。     

罗汉松实氨基酸和矿质元素含量测定

[目的]测定罗汉松实的氨基酸和矿质元素含量,为罗汉松果实的药效学研究及开发利用提供依据。[方法]采用氨基酸分析仪和原子吸收法对罗汉松实的氨基酸和矿质元素进行测定。[结果]罗汉松种子和花托总氨基酸含量（以鲜品计）分别为2770．5me／100g和466．1mg／100g,药用氨基酸含量高达63．2％和62．0％。罗汉松种子和花托均含有Ca、Fe、Mg、Zn、Mn和Cu元素,其中Ca含量最高,分别为69．9mg／100g和21．6mg／100g。[结论]试验测得罗汉松实17种氨基酸和6种矿质元素,分析认为罗汉松实氨基酸和矿质元素含量特点与其药用价值密切相关。     

光棘球海胆性腺氨基酸组成的研究

于2006年5、6、8月测定了光棘球海胆Strongylocentrotus nudus雌、雄个体性腺中氨基酸含量及组成。结果表明：光棘球海胆氨基酸含量为30．75％～48．52％（质量分数,下同）,其中鲜味氨基酸含量为15．33％～21．84％,必需氨基酸含量占氨基酸总量的42．67％-52．50％,鲜味氨基酸含量占总氨基酸含量的43％以上。光棘球海胆中甘氨酸含量最高（3．76％～5．02％）,谷氨酸含量（2．99％～4．79％）次之;雌、雄个体以及排放精、卵时其氨基酸组成变化较大;过熟及迟熟的海胆无论是氨基酸总量,还是必需氨基酸、鲜味氨基酸含量都低于早期成熟海胆;雄性海胆性腺鲜味氨基酸含量高于雌性,因此雄性更美味。研究表明,生产中采集海胆最好在海胆早期成熟阶段,在海胆成熟后期自然排放之前采收完毕。