英国科学家研制最精密的人造胃

英国研究人员正在开发一种人造胃,相信这将是世界上第1个也是最精密的人造胃。 这种人造胃将能解答食品结构、生物活性成分潜力和普通食品安全等问题．并且经过进一步开发,这种装置能够替代或是先于高成本的人体生物实验,从而在药品测试中对药物进行评估。这一内脏模型由英国食品研究所的科学家负责研发,这可能是目前唯一的能够把消化时出现的物理、机械和生物化学环境知识结合在一起的人类胃模型。     

昆虫嗅觉策略的进化

洛克菲勒大学和东京大学的研究人员发现,昆虫利用快速反应离子通道感知气味,这是一种完全不同于其他生物的嗅觉机制,也是生物进化领域的一大突破。达尔文生物进化树描绘了生物的进化路线,并可推测当代生物多样性的演化历程,而这项关于离子通道进化的结果有可能导致现有进化树的重构。     

亿年前琥珀现奇特苍蝇:头上长角生5只眼

9700万年至1.1亿年前的琥珀,其中包裹着1只长相奇特的远古苍蝇。它的头上长有1个角并且生有5只眼睛,很容易发现捕食者的踪影;其中有1对巨大的复眼,与今天的很多昆虫类似。研究人员表示,当时胶粘的树液滴落到这只苍蝇身上,使其生动逼真的细节特征得以保存而后逐渐硬化。这种新发现的物种现在被称之为“Cascopleciainsolitis”,能够让科学家更好地了解古代生态系统以及动物居民的细节。美国俄勒冈州大学动物学教授、     

对“老蚊子”下手有望剿灭疟疾

快点儿杀死它们,并且越早越好。在过去的50年中,这句话一直是消灭害虫的非官方座右铭。然而一项新的研究表明,至少对疟疾来说,这种策略是错误的。通过选择见效更缓慢的杀虫剂,或者将更年老的蚊子作为目标,研究人员将能够防止杀虫剂抗性——一个长期困扰疟疾防治工作的难题一的进化。     

蜜蜂嗡嗡吓跑植物害虫

人类失去蜜蜂,世界将会怎样？这些小昆虫为我们带来蜂蜜,并且在全世界为数以百计的粮食作物授粉。研究人员如今发现,蜜蜂在保障人类的粮食安全方面还扮演了一个重要角色——它们发出的嗡嗡声能够保护庄稼和其他植物免遭甜菜黏虫的侵袭。植物的叶、花和果实都能成为甜菜黏虫的食物。但是甜菜黏虫也有自己的天敌：黄蜂。为了防范黄蜂,甜菜黏虫进化出了感觉毛——能够感知黄蜂拍打翅膀所产生的空气震动。     

果蝇及寄生于该果蝇的胡蜂快速进化出新物种

2009年2月6日的《Science》杂志刊登了美国研究人员新发现：一种新果蝇的出现伴随着一种新胡蜂的出现。研究人员表示,近400年前将苹果引进美洲可能改变了一种果蝇的行为,其自身的改变又导致寄生于该果蝇的胡蜂的行为改变。这是一种生物多样性链式反应,一个物种的改变导致依赖其生存的物种相继发生改变。     

A revision of Clematis sect. Atragene （Ranunculaceae）

Clematis sect. Atragene is revised in this paper based on the examination of a large number of herbarium specimens, extensive field observations, and morphometric analyses. Brief taxonomic history and geographical distribution of the section are given, the relationships among the species are discussed, and the evolutionary trends of some characters in the section are evaluated. The staminodes of the plants in this section may have evolved from the outer stamens with petaloid filaments and gradually disappearing anthers. Subsequently, they may have evolved in two different ways. One possibility is that the staminodes elongate and become lanceolate, as long as sepals, and their apices turn into attenuate. The other is that the staminodes are spathulate, but not elongating, as long as stamens, and their apices turn into retuse from obtuse and rounded. The evolutionary trend of sepals may be from thin to thick in texture, and the veins from non-prominent to prominent. As a result, five new series are established and nine species, two subspecies and nine varieties （including three new ranks） are recognized in this section. An identification key is provided, and each taxon is described and illustrated. Clematis sibirica and Clematis ochotensis are treated as subspecies of Clematis alpina due to their subtle differences and lack of, or few, overlapping distributions. Clematis fusijamana and Clematisfauriei are recognized as varieties of C. alpina ssp. ochotensis for the continuous variation of the velutinous strips on the sepal margins. Clematis iliensis is treated as variety of C. alpina ssp. sibirica for the continuous variation of leaf division types. Extensive variations in sepal color and basal caruncle size support degrading Clematis chiisanensis as a variety of Clematis koreana. The North American ser. Occientales may be primitive, whereas ser. Macropetalae may be the most advanced taxon in this section. Ser. Alpinae and ser. Koreanae are closely related to each other. However, the systematic position of ser.     

Construction of a Bacterial Artificial Chromosome Library of TM-1, a Standard Line for Genetics and Genomics in Upland Cotton

A bacterial artificial chromosome （BAC） library was constructed for Gossypium hirsutum acc. TM-1, a genetic and genomic standard line for Upland cotton. The library consists of 147 456 clones with an average insert size of 122.8 kb ranging from 97 to 240 kb. About 96.0% of the clones have inserts over 100 kb. Therefore, this library represents theoretically 7.4 haploid genome equivalents based on an AD genome size of 2 425 Mb. Clones were stored in 384 384- well plates and arrayed into multiplex pools for rapid and reliable library screening. BAC screening was carried out by four-round poiymerase chain reactions using 23 simple sequence repeats （SSR） markers, three sequence-related amplified polymorphism markers and one pair of primers for a gene associated with fiber development to test the quality of the library. Correspondingly, in total 92 positive BAC clones were identified with an average four positive clones per SSR marker, ranging from one to eight hits. Additionally, since these SSR markers have been localized to chromosome 12 （A12） and 26 （D12） according to the genetic map, these BAC clones are expected to serve as seeds for the physical mapping of these two homologous chromosomes, sequentially map-based cloning of quantitative trait loci or genes associated with important agronomic traits.     

Mobilization and Acquisition of Sparingly Soluble P-Sources by Brassica Cultivars under P-Starved Environment I. Differential Growth Response,P-Efficiency Characteristics and P-Remobilization

Phosphorus （P） starvation is highly notorious for limiting plant growth around the globe. To combat P-starvation, plants constantly sense the changes in their environment, and elicit an elegant myriad of plastic responses and rescue strategies to enhance P-solublization and acquisition from bound soil P-forms. Relative growth responses, P-solublization and P- acquisition ability of 14 diverse Brassica cultivars grown with sparingly soluble P-sources （Rock-P （RP） and Ca3（PO4）2 （TCP）） were evaluated in a solution culture experiment. Cultivars showed considerable genetic diversity in terms of biomass accumulation, concentration and contents of P and Ca in shoots and roots, P-stress factor （PSF） and P use efficiency. Cultivars showed variable P-stress tolerance, and cultivars depicting low PSF and high P-efficiency values were better adaptable to P-starvation. In experiment 2, after initial feeding on optimum nutrition for 12 d after transplanting （DAT）, class-I （low P-tolerant （Oscar and Con-II）） and class-II （low P-sensitive （Gold Rush and RL-18）） cultivars were exposed to P-free environment for 25 d. All of the cultivars remobilized P from above ground parts to their roots during growth in P-free environment, the magnitude of which was variable in tested cultivars. P-concentrations （[P]s） at 37 DAT were higher in developing compared with developed leaves. Translocation of absorbed P from metabolically inactive to active sites in P- stressed plants may have helped class-I cultivars to establish a better rooting system, which provided a basis for enhanced P-utilization efficiency （PUE） and tolerance against P-stress. By supplying TCP and RP spatially separated from other nutrients in split root study, class-I cultivars were still able to mobilize RP and TCP more efficiently compared with class-II cultivars. To compare the growth behavior under P-stress, cultivars were grown in pots for 41 d after sowing, using a soil low in P （NaHCO3-extractable P = 3.97 mg/kg, M