Chromosome aberrations in workers of nuclear-power plants

The frequencies of chromosome aberrations in 135 workers from nuclear-power plants were compared with those in 135 age-matched controls. A total of 135,000 cells was scored. The frequencies of dicentric chromosome were 1.67 × 10⁻³ in the exposed group and 0.49 × 10⁻³ in the control group and those of chromosome-type deletion were 3.33 × 10⁻³ and 1.10 × 10⁻³, respectively. The frequencies of all types of chromosome aberrations in the exposed subjects were higher than those in the control group, but no significant trend of dose-dependent increase was observed when only the exposed group were considered. Poisson regression analysis, with both exposed and control included, showed that there was a significant association of chromosome aberration with radiation dose and the duration of work, but not with age, smoking habit and alcohol intake. It was also found that recent exposure to radiation, within the last 5 years, had contributed more to the observed chromosome aberration than earlier exposure.     

The impact of migration on the marriage structure in Fontanigorda

Until World War II the economic activity of the inhabitants of the commune of Fontanigorda (Genova — Italy) was based on subsistence farming and temporary migration. Migration to France in search of work absorbed the excess active male population: the isonymy study shows that the migrants were recruited from all the families of the commune. After having left for Marseilles or the mine at St. Maime (in the Alps of Upper Provence), these young migrants returned to their home town to marry. This behaviour maintained a high degree of consanguinity, obscured by a false exogamy, at least until the turn of the century. After this period, lifelong migration completely modified the pattern of marriage structure bacause migration to France became definitive.     

Continuity,Collapse or Metamorphosis? Demographic anthropology and the study of change within human populations.Foreword

this first paper introduces the topic of the volume, outcomes of a symposium organised at the 13th ICAES held in Mexico in August 1993. It briefly reminds of the convergence between anthropology and demography up to date and stresses on the need of real transdisciplinary work in this challenging domain. The aim of the symposium was to make a contribution on the central theme chosen by the congress — the cultural and biological dimensions of global change — while examining the place of demographic anthropology in the study of change. The papers presented at the symposium have been organised in three parts which form the present volume: the composition of population, the choice of spouse and mobility, the reproduction and dynamics of populations. The basic mechanisms of change are considered through examples at the level of local populations. This also leads to question the definitions of human groups and to make a “declaration” stressing on the importance of individual heterogeneity and the arbitrariness and reductive nature of any grouping of individuals, stating therefore the misapprehension of the most recent scientific work inherent to the rationale of programs of “ethnic cleasing”. Translated from the french by prof. Derek F. Roberts     

羊狂蝇化蛹、羽化的生物学研究

本文揭示羊狂蝇羽化与环境因素的相关性,幼虫在土壤栖息定位,蛹态,蛹与幼虫大小的相关性,成蝇活动行为和寿命,雌雄蝇比率等生物学特性,为羊狂蝇应用研究提供具有指导意义的基础资料。     

可育的抗除草剂溴苯腈转基因小麦

报道了采用微粒轰击（Ｍｉｃｒｏｐｒｏｊｅｃｔｉｌｅ ｂｏｍ ｂａｒｄｍ ｅｎｔ） 幼胚将除草剂抗性基因导入小麦（Ｔｒｉｔｉｃｕｍａｅｓｔｉｖｕｍ Ｌ．）的转化研究。实验共使用了１３ 个小麦品种, 从开花后１４～１８ ｄ 的籽粒中剥取幼胚, 植物表达质粒含有ＣａＭＶ ３５Ｓ启动子控制的除草剂溴苯腈抗性基因ｂｘｎ 以及筛选标记基因ＮＴＰⅡ。采用高压放电基因枪,用质粒ＤＮＡ 包被的钨粒轰击预培养３ ｄ 的幼胚。在含有卡那霉素类似物ｇｅｎｅｔｉｃｉｎ Ｇ４１８ｓｕｌｐｈａｔｅ 的ＭＳ培养基上, 经过多步骤筛选和分化, 从８００ 多个幼胚中获得了１６ 株转化苗。除草剂抗性鉴定和Ｓｏｕｔｈｅｒｎ 杂交分析证明, 其中４ 株为转基因植物,具有溴苯腈抗性, 并且自交可育。转化工作从分离幼胚到转化苗鉴定完毕, 最短时间为６ 个月, 因此, 该方法是一项快速有效的基因导入技术     

A flash-photolysis study of the reactions of acaa 3-ttype cytochrome oxidase with dioxygen and carbon monoxide

The time course of absorbance changes following flash photolysis of the fully-reduced carboxycytochrome oxidase fromBacillus PS3 in the presence of O₂ has been followed at 445, 550, 605, and 830 nm, and the results have been compared with the corresponding changes in bovine cytochrome oxidase. The PS3 enzyme has a covalently bound cytochromec subunit and the fully-reduced species therefore accommodates five electrons instead of four as in the bovine enzyme. In the bovine enzyme, following CO dissociation, four phases were observed with time constants of about 10 s, 30 s, 100 s, and 1 ms at 445 nm. The initial, 10-s absorbance change at 445 nm is similar in the two enzymes. The subsequent phases involving hemea and Cu_A are not seen in the PS3 enzyme at 445 nm, because these redox centers are re-reduced by the covalently bound cytochromec, as indicated by absorbance changes at 550 nm. A reaction scheme consistent with the experimental observations is presented. In addition, internal electron-transfer reactions in the absence of O₂ were studied following flash-induced CO dissociation from the mixed-valence enzyme. Comparisons of the CO recombination rates in the mixed-valence and fully-reduced oxidases indicate that more electrons were transferred from hemea ₃ toa in PS3 oxidase compared to the bovine enzyme.     

Isolation of a root-specific cDNA encoding a ns-LTP-like protein from the roots of bean (Phaseolus vulgaris L.) seedlings

A root-specific cDNA clone, PVR3, was isolated from a bean (Phaseolus vulgaris L.) root cDNA library by a differential screening procedure. The nucleotide sequence of PVR3 contains an open reading frame coding for an 11.14 kDa polypeptide of 102 amino acid residues; the first 25 amino acids correspond to the sequence characteristic of a signal peptide. Comparison of the deduced PVR3 polypeptide sequence with the polypeptide sequences of previously cloned genes indicates that PVR3 may encode a ns-LTP-like protein. Molecular modelling of the PVR3 protein predicts that it has a three-dimensional structure that is similar to the three-dimensional model determined from the maize ns-LTP. The PVR3 mRNA accumulated mainly in the roots of young seedlings. It can be detected at low levels in flowers, but it is not detected in other organs. Genomic Southern blot analysis indicates that the genomic DNA corresponding to PVR3 cDNA is encoded by a single gene or small gene family in the bean genome.     

Fate of elemental sulfur in an intertidal sediment

Abstract: Sediment from a tidal flat at Wedderwarden, near the mouth of the Weser estuary, northern Germany, was amended with elemental sulfur, and concentrations of metabolic end products were monitored. The production of both sulfate and sulfide was consistent with disproportionation as the most important fate of the added elemental sulfur. A population of bacteria conducting active elemental sulfur disproportionation was also enriched from the sediment. In the enrichments, containing both elemental sulfur and Fe oxides as a sulfide 'scrub', sulfide and sulfate were produced in a ratio of     , somewhat lower than the predicted ratio of     . The mismatch between predicted and observed production ratios is explained by the channelling of electrons into autotrophic or mixotrophic CO₂ fixation rather than sulfide formation. The production of organic carbon, in the correct amount to explain the observed sulfide to sulfate production ratio, was verified by organic carbon analysis. Finally, rates of sulfate reduction were identical in the elemental sulfur amended sediment, and in control sediment with no added sulfur. Hence, the heterotrophic bacterial community was completely unaffected by an active metabolism conducting elemental sulfur disproportionation.     

中国沿海代表性河口地区鳗苗群体形态特征的比较研究

本文报道了１９９２—１９９４年连续３年采自海南至辽宁（包括台湾）沿海７个代表性河口地区鳗苗群体的主要形态特征比较研究结果。４项计数性状和３项度量性状,差异系数分析结果未达到亚种差异水平;判别函数显示,大多数群体间存在显著差异,这种差异应源于遗传变异。各年差异变化无规律,可能与鳗苗漂游分布的随机性有关。     

中国脊翅叶蝉属种类记述（同翅目：叶蝉科）

本文记述４种中国脊翅叶蝉,其中包括１新种──杨氏脊翅叶蝉Ｐａｒａｂｏｌｏｐｏｎａｙａｎｇｉｓｐ．ｎ．,并报道了其中２个已知种的新分布地。文中还列有分种检索表。新种模式标本存西北农业大学昆虫博物馆。