大有希望的基因疗法

生命的正常活动都是由于基因的准确无误地表达的结果,万一某一基因出了毛病,就影响了细胞的正常生长,出现了一些“病症”。这些由于基因的变化而引起的病称为遗传病。到目前为止,已发现有3000种不同的遗传病。     

Camouflage Patterning in Maize Leaves Results from a Defect in Porphobilinogen Deaminase

Maize leaves are produced from polarized cell divisions that result in clonal cell lineages arrayed along the long axis of the leaf. We utilized this stereotypical division pattern to identify a collection of mutants that form chloroplast pigmentation sectors that violate the clonal cell lineages. Here, we describe the camouflage1 （cfl） mutant, which develops nonclonal, yellow-green sectors in its leaves. We cloned the cfl gene by transposon tagging and determined that it encodes porphobilinogen deaminase （PBGD）, an enzyme that functions early in chlorophyll and heme biosynthesis. While PBGD has been characterized biochemically, no viable mutations in this gene have been reported in plants. To investigate the in vivo function of PBGD, we characterized the cfl mutant. Histological analyses revealed that cfl yellow sectors display the novel phenotype of bundle sheath cell-specific death. Light-shift experiments determined that constant light suppressed cfl sector formation, a dark/light transition is required to induce yellow sectors, and that sectors form only during a limited time of leaf development. Biochemical experiments determined that of 1 mutant leaves have decreased PBGD activity and increased levels of the enzyme substrate in both green and yellow regions. Furthermore, the cfl yellow regions displayed a reduction in catalase activity. A threshold model is hypothesized to explain the cfl variegation and incorporates photosynthetic cell differentiation, reactive oxygen species scavenging, and PBGD function.     

《实验生物学与医学》：科学家研发出胞内即时影像检测共振传感器

来自EurekAlert的消息，伊利诺大学基因组生物学研究所的研究人员突破了FRET技术的局限性，开发了一个共振传感器，来检测细胞内的氧化还原动力学的即时影像，这一研究成果公布在《实验生物学与医学》（Experimental Biology and Medicine）杂志上。     

医学实验中常见设计类型的辨析及统计方法的合理选用

目的帮助医学研究工作者提高对常见统计应用识别能力,提高对统计学的正确利用率。方法：明确阐述秒种常见医学实验设计类型的异同点和应用场合,揭示常见统计应用错误的实质和危害性。结果：给出不适合用ｔ检验取代方差分析的充足理由和正确运用统计学的基本要领。结论：要提高实际工作者的统计学应用水平。需要经常对其进行统计培养,积极引导与统计学工作者开展科研协作。