Variable number tandem repeats – Their emerging role in sickness and health

Understanding the mechanisms regulating tissue specific and stimulus inducible regulation is at the heart of understanding human biology and how this translates to wellbeing, the ageing process, and disease progression. Polymorphic DNA variation is superimposed as an extra layer of complexity in such processes which underpin our individuality and are the focus of personalized medicine. This review focuses on the role and action of repetitive DNA, specifically variable number tandem repeats and SINE-VNTR-Alu domains, highlighting their role in modification of gene structure and gene expression in addition to their polymorphic nature being a genetic modifier of disease risk and progression. Although the literature focuses on their role in disease, it illustrates their potential to be major contributors to normal physiological function. To date, these elements have been under-reported in genomic analysis due to the difficulties in their characterization with short read DNA sequencing methods. However, recent advances in long read sequencing methods should resolve these problems allowing for a greater understanding of their contribution to a host of genomic and functional mechanisms underlying physiology and disease.     

胆汁三烯结合蛋白在大肠杆菌中的表达、复性与纯化

目的：合成胆汁三烯结合蛋白（BBP）基因并在大肠杆菌中表达,获得重组BBP纯化制品。方法：根据天然BBP的基因序列和大肠杆菌偏好密码子设计并合成BBP基因的引物,PCR扩增优化的BBP基因序列,克隆至载体pEasy-T3;测序正确后,将该序列克隆至表达载体pET-32a上,构建表达质粒,转化至大肠杆菌BL21（DE3）pLysS,在IPTG诱导下表达融合蛋白;采用Ni柱纯化融合蛋白。结果：PCR扩增获得了优化后的BBP基因序列,构建了表达载体pET-32a-BBP;SDS-PAGE分析表明表达的融合蛋白相对分子质量为20×10^3,以包涵体形式存在,占全菌蛋白的40%以上;变性、复性后经Ni2＋柱纯化,获得纯度达98%以上的重组蛋白。结论：优化并合成了BBP全基因序列,获得了高纯度重组融合蛋白,为进一步鉴定其生物活性及筛选小分子的研究奠定了基础。     

Contractile behavior of the forelimb digital flexors during steady-state locomotion in horses (Equus caballus): an initial test of muscle architectural hypotheses about in vivo function

The forelimb digital flexors of the horse display remarkable diversity in muscle architecture despite each muscle-tendon unit having a similar mechanical advantage across the fetlock joint. We focus on two distinct muscles of the digital flexor system: short compartment deep digital flexor (DDF(sc)) and the superficial digital flexor (SDF). The objectives were to investigate force-length behavior and work performance of these two muscles in vivo during locomotion, and to determine how muscle architecture contributes to in vivo function in this system. We directly recorded muscle force (via tendon strain gauges) and muscle fascicle length (via sonomicrometry crystals) as horses walked (1.7 m s(-1)), trotted (4.1 m s(-1)) and cantered (7.0 m s(-1)) on a motorized treadmill. Over the range of gaits and speeds, DDF(sc) fascicles shortened while producing relatively low force, generating modest positive net work. In contrast, SDF fascicles initially shortened, then lengthened while producing high force, resulting in substantial negative net work. These findings suggest the long fibered, unipennate DDF(sc) supplements mechanical work during running, whereas the short fibered, multipennate SDF is specialized for economical high force and enhanced elastic energy storage. Apparent in vivo functions match well with the distinct architectural features of each muscle.     

A saturated SSR/DArT linkage map of Musa acuminata addressing genome rearrangements among bananas

Background

The orderly progression through mitosis is regulated by the Anaphase-Promoting Complex (APC), a large multiprotein E₃ ubiquitin ligase that targets key cell-cycle regulators for destruction by the 26 S proteasome. The APC is composed of at least 11 subunits and associates with additional regulatory activators during mitosis and interphase cycles. Despite extensive research on APC and activator functions in the cell cycle, only a few components have been functionally characterized in plants.

Results

Here, we describe an in-depth search for APC subunits and activator genes in the Arabidopsis, rice and poplar genomes. Also, searches in other genomes that are not completely sequenced were performed. Phylogenetic analyses indicate that some APC subunits and activator genes have experienced gene duplication events in plants, in contrast to animals. Expression patterns of paralog subunits and activators in rice could indicate that this duplication, rather than complete redundancy, could reflect initial specialization steps. The absence of subunit APC7 from the genome of some green algae species and as well as from early metazoan lineages, could mean that APC7 is not required for APC function in unicellular organisms and it may be a result of duplication of another tetratricopeptide (TPR) subunit. Analyses of TPR evolution suggest that duplications of subunits started from the central domains.

Conclusions

The increased complexity of the APC gene structure, tied to the diversification of expression paths, suggests that land plants developed sophisticated mechanisms of APC regulation to cope with the sedentary life style and its associated environmental exposures.     

黑色素瘤相关抗原MAAT1p15与LRP6的相互作用及其对Wnt信号通路的调控

为了深入研究Wnt信号的传导机制 ,利用GAL4酵母双杂交系统 ,以Wnt受体LRP6的胞内区为诱饵蛋白 ,筛选小鼠 11 5d胚胎cDNA文库 ,发现了一个新的LRP6相互作用蛋白 :黑色素瘤相关抗原MAAT1p15 (melanoma associatedantigenrecognizedbycytotoxicTlymphocytesp15 ) .免疫共沉淀方法证明了LRP6胞内区和MAAT1p15在哺乳动物细胞中也存在相互作用 .荧光素酶报告系统分析实验显示 ,MAAT1p15能够明显增强Wnt1和LRP6响应的下游基因的转录活性 ,提示MAAT1p15可能是LRP6的一个辅助蛋白     

圈养大熊猫性情、饲养管理和社群-性行为的关系

以往研究表明,许多成年雄性大熊猫在圈养状态下不能表达正常的社群性行为。我们设计了一个实验来研究大熊猫正常社群性行为与性情特征、展示、以及饲养管理的关系。通过调查获得大熊猫展示和饲养管理的数据,询问饲养员得知2001年繁殖季节中大熊猫的社群性行为发生频次,然后评估社群性行为能力。研究对象是分布在中国4个繁育中心的37头(12头雄性和25头雌性)成体大熊猫。通过提供新物品和气味来评估大熊猫情绪反应状况。情绪反应分为3类:畏惧、访问和访问玩耍。在有饲养员陪同玩耍的一组里,雌、雄大熊猫的"访问玩耍"的分值都较高。"畏惧"类的雌性大熊猫气味标记行为少,表达的性行为也少,并且更多地攻击接近它们的雄性,或者不理睬雄性。在繁殖季节前就接近雄性大熊猫围栏的雌性,表现出更多的气味标记行为和性行为。这些雌性的"访问玩耍"分值也高。"访问"分值高的雄性大熊猫,接近雌性的行为更多。那些与饲养员接触时间少的雄性大熊猫倾向于攻击雌性,与那些攻击性小的雄性相比,这些雄性倾向于能够接受丰富性低的环境。这些结果表明,应该采取措施减少大熊猫的畏惧,在大熊猫和饲养员之间建立积极的关系,在繁殖季节之前,增加雌性和雄性之间的熟悉程度。     

The Concept of Electroosmotically Driven Flow and Its Application to Biomimetics

1　IntroductionOneaimofthephysicsscienceresearchistodevel opfundamentalandportableconceptswhichhelpunitedifferentresearchfrontiers.Inthisrespect ,Helmholtz’selectricdoublelayer (DEL)theory ,whichwasdevel opedin 1879andrelatedtheelectricandflowparame tersforelectrokinetictransport ,isaseminal,havingprovidedaframeworkforinterpretingawiderangeofelectrokineticphenomena .DespitethesimplicityoftheEDLtheory ,whichwewilldescribeindetail,ithasprovidedachallengeformathematicianstounderstanditsimplic…     

Symbiosome-like intracellular colonization of cereals and other crop plants by nitrogen-fixing bacteria for reduced inputs of synthetic nitrogen fertilizers

It has been forecast that the challenge of meeting increased food demand and protecting environmental quality will be won or lost in maize, rice and wheat cropping systems, and that the problem of environmental nitrogen enrichment is most likely to be solved by substituting synthetic nitrogen fertilizers by the creation of cereal crops that are able to fix nitrogen symbiotically as legumes do. In legumes, rhizobia present intracellularly in membrane-bound vesicular compartments in the cytoplasm of nodule cells fix nitrogen endosymbiotically. Within these symbiosomes, membrane-bound vesicular compartments, rhizobia are supplied with energy derived from plant photosynthates and in return supply the plant with biologically fixed nitrogen, usually as ammonia. This minimizes or eliminates the need for inputs of synthetic nitrogen fertilizers. Recently we have demonstrated, using novel inoculation conditions with very low numbers of bacteria, that cells of root meristems of maize, rice, wheat and other major non-legume crops, such as oilseed rape and tomato, can be intracellularly colonized by the non-rhizobial, non-nodulating, nitrogen fixing bacterium, Gluconacetobacter diazotrophicus that naturally occurs in sugarcane. G. diazotrophicus expressing nitrogen fixing (nifH) genes is present in symbiosome-like compartments in the cytoplasm of cells of the root meristems of the target cereals and non-legume crop species, somewhat similar to the intracellular symbiosome colonization of legume nodule cells by rhizobia. To obtain an indication of the likelihood of adequate growth and yield, of maize for example, with reduced inputs of synthetic nitrogen fertilizers, we are currently determining the extent to which nitrogen fixation, as assessed using various methods, is correlated with the extent of systemic intracellular colonization by G. diazotrophicus, with minimal or zero inputs.     

The Somatic Function of the Germ Nucleus in Pseudourostyla cris tat a: Asexual Reproduction and Stomatogenesis

The micronuclei of the ciliated protozoan Pseudourostyla cristata were eliminated by amputation shortly before binary fusion. The amicronucleate cell lines derived from regenerants were maintained for more than a year. They exhibited a lower viability and reduced vigor in asexual propagation. There was some improvement in the growth of the cell lines 1 mo after operation, but the growth rate remained subnormal even up to 1 yr of culture. The exact cause of the poor growth and survival in the first 3 wk after operation, whether the loss of the micronucleus or operational damage, remains to be determined. It is nevertheless clear that the micronucleus is important for subsequent asexual propagation. The amicronucleate cell lines were permanently crippled in morphogenesis, unlike the situation in Paramecium amicronucleates in which stomatogenesis returned to near-normal during asexual propagation. They always included some cells with a characteristically defective adoral zone of membranelles, reduced number of frontal-ventral-transverse cirri, and reduced body length. They were also reluctant to encyst. It is evident that the micronucleus is important for maintaining normality of the oral apparatus. It is postulated that the permanent stomatogenic crippling of amicronucleates might be related to genomic reduction in the developing macronucleus in sexual reproduction, as exhibited by other hypotrichs. The morphological defects associated with the adoral zone of membranelles may be rationalized as arising from the spreading of a zone of degeneration in the cortex affecting the left edge of the membranelles.     

男性腿黑激素和N-乙酰-5-羟色胺血浓度的观察

在三个年龄组的中国男性中,对其血液腿黑激素和 N-乙酰-5-羟色胺进行了定量观察。血样本分别于下午4—5时和夜间0—2时,从青春期前、成年和老年三个年龄组采取。分别采用二氯甲烷和甲醇提取血液中的腿黑激素和 N-乙酰-5-羟色胺,用放射免疫法进行测定。实验结果表明,腿黑激素血水平夜间呈节律性的升高,且其血浓度的降低与年龄相关。血液中 N-乙酰-5-羟色胺的水平可能呈昼高夜低的节律性,其血浓度的高低与年龄无关。