Influence of pinealectomy on serum estrogen and progesterone levels in blind-anosmic female rats

Summary Previous studies show that the suppression of gonadal function in blind-anosmic rats is dependent on the pineal gland. The present results demonstrate that in young female rats both the pineal gland and dual sensory deprivation have additional independent antigonaldal effects.This work was partially supported by state institutional funds and by NSF grant No. PCM 74-06276-276-A02. The radioimmunoassays of the steroids were carried out with the aid of the Radioimmunoassay Core which is supported by USPHS grant No. 1T30 HD-10202. We also thank Constance Stahl for typing assistance.     

Identification ofTrypanosoma theileri as a contaminant in primary cultures of bovine retina

Summary T. theileri has been isolated from primary cultures of bovine retina and subcultered successfully for 2 passages in sub-confluent cultures. When cultures reached confluency no trypomastigotes or epimastigotes could be detected and attempts to recover trypanosomes from these cultures were unsuccessful. The presence of intracellular forms could not formally be excluded.We wish to thank Dr S. Dershko, Division of Meat Inspection, Health of Animals Branch, Department of Agriculture (Canada) and Intercontinental Packers, Ltd. for their assistance in obtaining the freshest possible specimens. The skillful technical assistance of Mrs J. Graham is also gratefully acknowledged. This investigation was supported by the M. R. C. of Canada.     

形状记忆材料的热力学设计

以新一代溶液模型考察了合金元素对Fe-Mn-Si基合金层错能的影响，并预测了Fe-Mn-Si合金面心立方(fcc)→密排六方(hcp)马氏体的相变温度．应用规则溶液模型计算了含Ce和Y的ZrO2基陶瓷四方(t)→单斜(m)马氏体相变的自由能，结合测得ZrO2基陶瓷的强度，预测了马氏体相变的开始温度．对Ni-Mn-Ga磁驱动记忆合金的磁性转变温度Tc、体心立方至体心正方(bcc→bct)马氏体相变温度Tmart和饱和磁化强度Ms与成分的关系进行了优化，提出了具有较佳综合性能的成分范围．应用热力学方法对Fe-Mn-Si基合金、ZrO2基陶瓷和Ni-Mn-Ga铁磁合金等形状记忆材料作出的成分设计均与实验结果符合较好．     

复杂曲面的无干涉刀位轨迹生成

提出了基于X－map思路的干涉处理方法，将干涉处理由空间三角片之间的距离判断简化为一维坐标轴上两点之间的位置比较，并构造了包括干涉检查、干涉消除及欠切区域处理等的完整干涉处理方法，此法可以提高干涉处理的效率及稳定性，简化欠切区域的单独处理，对三坐标加工的干涉处理具有很好的实用价值。     

The Phaeodactylum genome reveals the evolutionary history of diatom genomes

Diatoms are photosynthetic secondary endosymbionts found throughout marine and freshwater environments, and are believed to be responsible for around one-fifth of the primary productivity on Earth. The genome sequence of the marine centric diatom Thalassiosira pseudonana was recently reported, revealing a wealth of information about diatom biology. Here we report the complete genome sequence of the pennate diatom Phaeodactylum tricornutum and compare it with that of T. pseudonana to clarify evolutionary origins, functional significance and ubiquity of these features throughout diatoms. In spite of the fact that the pennate and centric lineages have only been diverging for 90 million years, their genome structures are dramatically different and a substantial fraction of genes ( approximately 40%) are not shared by these representatives of the two lineages. Analysis of molecular divergence compared with yeasts and metazoans reveals rapid rates of gene diversification in diatoms. Contributing factors include selective gene family expansions, differential losses and gains of genes and introns, and differential mobilization of transposable elements. Most significantly, we document the presence of hundreds of genes from bacteria. More than 300 of these gene transfers are found in both diatoms, attesting to their ancient origins, and many are likely to provide novel possibilities for metabolite management and for perception of environmental signals. These findings go a long way towards explaining the incredible diversity and success of the diatoms in contemporary oceans.     

Strain-resolved community proteomics reveals recombining genomes of acidophilic bacteria

Microbes comprise the majority of extant organisms, yet much remains to be learned about the nature and driving forces of microbial diversification. Our understanding of how microorganisms adapt and evolve can be advanced by genome-wide documentation of the patterns of genetic exchange, particularly if analyses target coexisting members of natural communities. Here we use community genomic data sets to identify, with strain specificity, expressed proteins from the dominant member of a genomically uncharacterized, natural, acidophilic biofilm. Proteomics results reveal a genome shaped by recombination involving chromosomal regions of tens to hundreds of kilobases long that are derived from two closely related bacterial populations. Inter-population genetic exchange was confirmed by multilocus sequence typing of isolates and of uncultivated natural consortia. The findings suggest that exchange of large blocks of gene variants is crucial for the adaptation to specific ecological niches within the very acidic, metal-rich environment. Mass-spectrometry-based discrimination of expressed protein products that differ by as little as a single amino acid enables us to distinguish the behaviour of closely related coexisting organisms. This is important, given that microorganisms grouped together as a single species may have quite distinct roles in natural systems and their interactions might be key to ecosystem optimization. Because proteomic data simultaneously convey information about genome type and activity, strain-resolved community proteomics is an important complement to cultivation-independent genomic (metagenomic) analysis of microorganisms in the natural environment.     

工业石膏在自来水厂污泥调解和脱水中的作用

自来水厂污泥的处理和利用是一个至今没有得到完全解决的问题,通常的做法是将其直接排放或脱水后填埋.在实验研究的基础上,论述了采用工业石膏(CaSO4·2H2O)和有机聚合物对自来水厂污泥进行双重调解进而脱水的方法.实验结果表明,用11(工业石膏和有机聚合物的重量比)的投量对自来水厂污泥进行双重调解可明显改善污泥的过滤性能.脱水实验证明双重调解后的污泥经机械脱水,其泥饼含水率可比单纯有机聚合物调解后脱水的泥饼含水率低大约7个百分点.此项研究的意义在于探索自来水厂污泥脱水后农用及作为人工湿地填料的可能性,同时也为自来水厂污泥脱水后的最终处置探索新思路.     

The molecular evolution of acquired resistance to targeted EGFR blockade in colorectal cancers

Colorectal tumours that are wild type for KRAS are often sensitive to EGFR blockade, but almost always develop resistance within several months of initiating therapy. The mechanisms underlying this acquired resistance to anti-EGFR antibodies are largely unknown. This situation is in marked contrast to that of small-molecule targeted agents, such as inhibitors of ABL, EGFR, BRAF and MEK, in which mutations in the genes encoding the protein targets render the tumours resistant to the effects of the drugs. The simplest hypothesis to account for the development of resistance to EGFR blockade is that rare cells with KRAS mutations pre-exist at low levels in tumours with ostensibly wild-type KRAS genes. Although this hypothesis would seem readily testable, there is no evidence in pre-clinical models to support it, nor is there data from patients. To test this hypothesis, we determined whether mutant KRAS DNA could be detected in the circulation of 28 patients receiving monotherapy with panitumumab, a therapeutic anti-EGFR antibody. We found that 9 out of 24 (38%) patients whose tumours were initially KRAS wild type developed detectable mutations in KRAS in their sera, three of which developed multiple different KRAS mutations. The appearance of these mutations was very consistent, generally occurring between 5 and 6 months following treatment. Mathematical modelling indicated that the mutations were present in expanded subclones before the initiation of panitumumab treatment. These results suggest that the emergence of KRAS mutations is a mediator of acquired resistance to EGFR blockade and that these mutations can be detected in a non-invasive manner. They explain why solid tumours develop resistance to targeted therapies in a highly reproducible fashion.