健康·风向标

哈欠越打越清醒？；有痛苦多倾诉；健康快乐并不难!；煮沸蔬菜破坏其中的抗癌物质；甜食并非肥胖“元凶”？；     

健康·风向标

吃香蕉致便秘？；芥末可以预防龋齿？；仙人掌能防电脑辐射未经证实；喝咖啡有助于预防帕金森氏症；你适合吃西瓜吗？     

健康·风向标

办公桌上养金鱼可缓解干眼症；喝豆奶预防啤酒肚？脂肪摄入过量影响生物钟；米饭是最好的催眠剂？科学家证实人言可畏？越想忘越忘不掉；     

健康·风向标

饮用水中的氯化物增加了患癌症的风险吗？食盐过多会失明？别和狗狗对视；番茄和西兰花同吃可防前列腺癌；想变聪明多吃野果……     

遗传性平衡易位t(3; 22) (p21; q13）家系

本文报道一例t(3; 22) (p21; q13）平衡 相互易位的家系。先证者，男性，一岁半，淋巴 细胞及皮肤成纤维细胞G带分析结果：核型均 为46, XY, t(3; 22)(p21；q13）或46, XY,t(3; 22)(3gter” 3p21：：22813” 22gter；2 2 pter” 22gl3::3p21” 3 pter )；先证者母亲（图1）与 外祖母核型均为46, XX, t(3; 22)(p21; q13) 或46, XX, t(3; 22)(3gter、3p21：:22813一 22gter; 22pter～ 22813：:3p21一3pter)。经银 染与G带复合显示技术，先证者及母亲的22der 可见清晰的AgNOR区。先证者的父亲与舅父 G带分析核型正常。在此情况下，有生育正常 婴儿的可能，但必须作产前诊断。     

"基因隐私权与信息"生命伦理学教学设计

1选题依据 人类基因组草图的测定引起了巨大的轰动，除了人类基因组计划本身巨大的科学价值之外，一个重要的原因就是它对伦理、法律和其他一些社会问题产生了深远的影响。比如，恋爱男女间、已婚夫妻间的基因隐私权与知情权的冲突；保险公司、用人单位、银行、学校、档案部门、公安机关等社会组织一旦知悉公民的基因信息是否会侵犯他们的隐私权？     

家猪rob（13;17）的联会复合体分析

经对亲代公猪以及其部分子公代公猪的染色体进行Ｇ－带和Ｃ－带分析，发现它们均携有ｒｏｂ（１３；１７），其染色体组成为２ｎ＝３７，ＸＹ，ｒｏｂ（３；１７）。本文采用表面铺展法，硝酸银染色技术对这些杂合易位公猪的ｒｏｂ（１３；１７）减数分裂的配对行为进行了联会复合体（Ｓｙｎａ－ｐｔｏｎｅｍａｌ Ｃｏｍｐｌｅｘ，ＳＣ）的电镜观察和分析，结果表明：ｒｏｂ（１３；１７）的（未配对的）ＳＣ侧生组分与１３，１７二     

·遗传咨询·

1．多囊肾的遗传 问：我有家族多囊肾遗传史,自己双肾有囊肿,现在怀孕29周,胎儿彩超双肾大,有回声,医生判定为多囊肾,我如果不要这胎,再怀孕,有不遗传的可能吗？     

Australopithecus afarensis : bipédie stricte ou associée à une composante arboricole ? Critiques et révision du matériel fémoral

Although much research has been carried out on Australopithecus afarensis locomotion, no consensus has yet been reached. Our new critic study on femoral material brings to the fore a strictly bipedal behaviour within this taxon. Our results are based on the pertinence of human anatomical characteristics among A. afarensis and on the absence of characteristics revealing arboreal displacement. These results have emerged from our different observation and interpretation of some preceding authors concerning the anatomy of these fossil hominids. It is important to underline that apomorphic characteristics of this species are difficult to interpret. They must not however be used to support the idea of arboreal displacement simply based on the fact of a no totally human morphe. We believe that present day humans do not necessarily reflect the earliest strict bipedal anatomic model. An the other hand, it appears that the disagreement between the two locomotor hypothesis for A. afarensis that are bipedalism and arboreal displacement, facing the possibility of bipedalism associated with negligible arboreal displacement, results more from an evolutionary fact than from a real scientific conflict.     

马克·史蒂文·普塔什尼

分子生物学的任务之一就是研究基因的表达,无论是低等的细菌,还是高等的哺乳动物甚至人,在特定的情况下只有部分基因表达,同时另外的部分则不表达,甚至在一个细胞内部的基因表达也存在这种状况,很自然基因开关的研究就成为生命科学领域最基本的问题之一。上世纪60年代,对该问题的研究深入到了分子水平,其中1967年哈佛大学的马克·史蒂文·普塔什尼（Mark Steven Ptashne）阻遏蛋白的发现掀开了该领域崭新的一页。     

哈罗德·埃利奥特·瓦姆斯

1939年12月18日,哈罗德·埃利奥特·瓦姆斯（Harold Eliot Varmus）出生于美国纽约东南部的欧申赛德社区,是犹太人的后裔。瓦姆斯的父亲弗兰克是纽约的一位家庭医生,母亲是当地一位精神病学方面的社会工作者,因此瓦姆斯的童年就在纽约度过。1957年,瓦姆斯进入到阿姆赫斯特学院进行医学预科班的学习,1961年,凭借一篇关于狄更斯的文学而获得文学学士学位。毕业后瓦姆斯甚至考虑将来可以将文学作为自己的职业,并于1962年又获得哈佛大学英语文学的硕士学位。     

“人类基因组计划”自启动至“后基因组计划”的转折

“人类基因组计划”自启动至“后基因组计划”的转折杨焕明（中国医学科学院中国协和医科大学教授）（中国“人类基因组计划”重大项目秘书长）今年是“人类基因组计划”（ＨｕｍａｎＧｅｎｏｍｅＰｒｏｊｅｃｔ,ＨＧＰ）正式提出十周年。对这一可与“曼哈顿原子弹计划”、“阿波罗登月计划”相媲美的创举作一历史性的回顾,纵览十年来这一计划的成果、瞻望这一计划的前景,对于我国抓住机遇,接受挑战是很有必要的。     

Chronic Atmospheric NO<Stack><Subscript>3</Subscript><Superscript>−</Superscript></Stack> Deposition Does Not Induce NO<Stack><Subscript>3</Subscript><Superscript>−</Superscript></Stack> Use by <Emphasis Type="Italic">Acer saccharum</Emphasis> Marsh.

The ability of an ecosystem to retain anthropogenic nitrogen (N) deposition is dependent upon plant and soil sinks for N, the strengths of which may be altered by chronic atmospheric N deposition. Sugar maple (Acer saccharum Marsh.), the dominant overstory tree in northern hardwood forests of the Lake States region, has a limited capacity to take up and assimilate NO₃⁻. However, it is uncertain whether long-term exposure to NO₃⁻ deposition might induce NO₃⁻ uptake by this ecologically important overstory tree. Here, we investigate whether 10 years of experimental NO₃⁻ deposition (30 kg N ha⁻¹ y⁻¹) could induce NO₃⁻ uptake and assimilation in overstory sugar maple (approximately 90 years old), which would enable this species to function as a direct sink for atmospheric NO₃⁻ deposition. Kinetic parameters for NH₄⁺ and NO₃⁻ uptake in fine roots, as well as leaf and root NO₃⁻ reductase activity, were measured under conditions of ambient and experimental NO₃⁻ deposition in four sugar maple-dominated stands spanning the geographic distribution of northern hardwood forests in the Upper Lake States. Chronic NO₃⁻ deposition did not alter the V _max or K _m for NO₃⁻ and NH₄⁺ uptake nor did it influence NO₃⁻ reductase activity in leaves and fine roots. Moreover, the mean V _max for NH₄⁺ uptake (5.15 μmol ¹⁵N g⁻¹ h⁻¹) was eight times greater than the V _max for NO₃⁻ uptake (0.63 μmol ¹⁵N g⁻¹ h⁻¹), indicating a much greater physiological capacity for NH₄⁺ uptake in this species. Additionally, NO₃⁻ reductase activity was lower than most values for woody plants previously reported in the literature, further indicating a low physiological potential for NO₃⁻ assimilation in sugar maple. Our results demonstrate that chronic NO₃⁻ deposition has not induced the physiological capacity for NO₃⁻ uptake and assimilation by sugar maple, making this dominant species an unlikely direct sink for anthropogenic NO₃⁻ deposition.     

Negative molecular ion of deuterium D<Stack><Subscript>2</Subscript><Superscript>−</Superscript></Stack>

D₂⁻ ions produced in collisions of D⁻ ions with relative energies of 2.5–9.2 eV were detected for the first time. It is shown that the effective cross section for this reaction is no less than 1.5 × 10⁻¹⁴ cm². Along with the theoretically predicted short-lived state of negative molecular deuterium ions, a state existing for more than 1 μs was observed.     

第19届国际生物学奥林匹克竞赛试题（1）理论A-1&#183;细胞生物学

2008年7月13—19日，第19届国际生物学奥林匹克竞赛（19th IBO）在印度孟买市举行。我国IBO代表队在2008年7月11日前往孟买,21日竞赛活动结束，代表队回国。逐渐被社会熟悉的IBO是一种国际中学生生物学竞赛，2008年来自55个国家和地区的220名中学生参加角逐。竞赛内容包括理论和实验考试2个部分，根据选手在理论和实验中的总成绩,按金、银、铜各10％、20％和30％的比例（只有60％的选手获奖），成绩排名前23名的选手获得金牌，47名选手获银牌、68人获铜牌。中国代表队参赛的4名学生（董雅韵、鲁昊骋、井淼和杨纪元）分别获得金、银牌；金牌得主董雅韵位居前3名行列。     

Flow of Deposited Inorganic N in Two Gleysol-dominated Mountain Catchments Traced with <Superscript>15</Superscript>NO<Subscript>3</Subscript><Superscript>−</Superscript> and <Superscript>15</Superscript>NH<Subscript>4</Subscript><Superscript>+</Superscript>

In two mountain ecosystems at the Alptal research site in central Switzerland, pulses of ¹⁵NO₃ and ¹⁵NH₄ were separately applied to trace deposited inorganic N. One forested and one litter meadow catchment, each approximately 1600 m², were delimited by trenches in the Gleysols. K¹⁵NO₃ was applied weekly or fortnightly over one year with a backpack sprayer, thus labelling the atmospheric nitrate deposition. After the sampling and a one-year break, ¹⁵NH₄Cl was applied as a second one-year pulse, followed by a second sampling campaign. Trees (needles, branches and bole wood), ground vegetation, litter layer and soil (LF, A and B horizon) were sampled at the end of each labelling period. Extractable inorganic N, microbial N, and immobilised soil N were analysed in the LF and A horizons. During the whole labelling period, the runoff water was sampled as well. Most of the added tracer remained in both ecosystems. More NO₃⁻ than NH₄⁺ tracer was retained, especially in the forest. The highest recovery was in the soil, mainly in the organic horizon, and in the ground vegetation, especially in the mosses. Event-based runoff analyses showed an immediate response of ¹⁵NO₃⁻ in runoff, with sharp ¹⁵N peaks corresponding to discharge peaks. NO₃⁻ leaching showed a clear seasonal pattern, being highest in spring during snowmelt. The high capacity of N retention in these ecosystems leads to the assumption that deposited N accumulates in the soil organic matter, causing a progressive decline of its C:N ratio.     

Delimiting a rice wide-compatibility gene <Emphasis Type="Italic">S</Emphasis><Stack><Subscript>5</Subscript><Superscript><Emphasis Type="Italic">n</Emphasis></Superscript></Stack> to a 50 kb region

Wide-compatibility (WC) is one of the most important traits in rice, which can overcome the fertility barrier in the indica/japonica hybrids, and hence to make it possible to utilize the higher yield potential of inter-subspecific hybrids. The S ₅ ⁿ gene located on chromosome 6 has been previously reported to be responsible for the wide-compatibility in rice. Here we report the precise location of the S ₅ ⁿ gene. In the first-pass mapping, the S ₅ ⁿ gene was restricted within a 200 kb region by using a population of 242 isogenic lines in combination with high-density markers developed in the S ₅ region. In the fine mapping, the S ₅ region was further saturated with newly developed markers and more isogenic lines (549 in total) were investigated. Eventually, the S ₅ ⁿ gene was mapped within a 50 kb region delimited by the left marker J13 and the right marker J17. One BAC clone screened from the BAC library of the WC rice variety 02428 covered the whole S ₅ region. Sequence analysis of the 50 kb region revealed two candidate genes, coding an aspartyl protease and a hypothetical protein. This result would greatly accelerate both cloning and marker-assisted selection of this important S ₅ ⁿ gene. Qing Ji and Jufei Lu have contributed equally to this paper.     

Estimation of denitrification potential in a karst aquifer using the <Superscript>15</Superscript>N and <Superscript>18</Superscript>O isotopes of NO<Stack><Subscript>3</Subscript><Superscript>−</Superscript></Stack>

A confined aquifer in the Malm Karst of the Franconian Alb, South Germany was investigated in order to understand the role of the vadose zone in denitrifiaction processes. The concentrations of chemical tracers Sr²⁺ and Cl^– and concentrations of stable isotope ¹⁸O were measured in spring water and precipitation during storm events. Based on these measurements a conceptual model for runoff was constructed. The results indicate that pre-event water, already stored in the system at the beginning of the event, flows downslope on vertical and lateral preferential flow paths. Chemical tracers used in a mixing model for hydrograph separation have shown that the pre-event water contribution is up to 30%. Applying this information to a conceptual runoff generation model, the values of ¹⁵N and ¹⁸O in nitrate could be calculated. Field observations showed the occurence of significant microbial denitrification processes above the soil/bedrock interface before nitrate percolates through to the deeper horizon of the vadose zone. The source of nitrate could be determined and denitrification processes were calculated. Assuming that the nitrate reduction follows a Rayleigh process one could approximate a nitrate input concentration of about 170 mg/l and a residual nitrate concentration of only about 15%. The results of the chemical and isotopic tracers postulate fertilizers as nitrate source with some influence of atmospheric nitrate. The combined application of hydrograph separation and determination of isotope values in ¹⁵N and ¹⁸O of nitrate lead to an improved understanding of microbial processes (nitrification, denitrification) in dynamic systems.