哺乳动物体细胞克隆技术研究现状及其存在的问题

哺乳动物体细胞克隆技术的成功是生物高新技术的重大突破,具有划时代里程碑的作用.在分析哺乳动物体细胞克隆技术的基本环节及其研究现状的基础上,对其产生的意义和存在的问题作了综合评述,并对其发展前景作了展望。     

哺乳动物起源、进化模糊问题思考

哺乳动物进化是生物进化的重要组成部分之一,是生物进化论、动物学研究的重要内容之一。根据古生物学、现代生物学、生物进化论研究成就,就哺乳动物确定、起源、翼手目进化、水栖哺乳动物进化中的模糊问题进行了分析思考。     

Nuclear transfer using nonquiescent adult fibroblasts from a bovine ear

The natural reproduction of mammal is sexual reproduction, which needs fertilization involving sperm and oocyte. Nuclear transfer provided an asexual reproduction method for mammal. Donor cells used in previous experiments of nuclear transfer were mostly from undifferentiated or non-terminally differentiated cells, such as embryonic or fetal cells. However, since Wilmutet al. obtained a viable lamb by transfer of an adult sheep somatic cell into an enucleated oocyte, nuclear transfer using adult somatic cell has been successful in several species. Wilmutet al. suggested that it was a key factor for the success of somatic nuclear transfer to induce the donor cells into GO phase (“GO-phase hypothesis”). In order to verify the Gophase hypothesis, nonquiescent adult fibroblasts from a bovine ear were transferred into enucleated bovine oocytes. The experiments showed that the rate of electrofusion after micromanipulation was above 50%, the cleaving rate was 54.5% and 9.1% of those reconstructed embryos developed to 32-cell stage. These results indicate that for cattle, nuclei from nonquiescent adult somatic cells introduced into enucleated oocytes are at least capable of supporting early development.     

A new family of primitive mammal from the Mesozoic of western Liaoning, China

A fairly well-preserved specimen of a new primitive mammal, Repenomamus robustus gen. et sp. nov., has been described from the Yixian Formation (Lower Cretaceous), western Liaoning, China. This animal has several derived characteristics, such as well-developed den-tary/squamosal articulation, reduced number of tooth, differentiation of premolars and molars in postcanine teeth, presence of a dorsal process of the premaxilla that is not in contact with the nasal, closed medial wall of the orbit, and presence of fingerlike promontorium on the petrosal. It also retains some primitive reptile-like features. It is the most primitive taxon among the three mammals known from the Jehol Biota, and also represents the largest mammal of Mesozoic age over the world.     

Large Mesozoic mammals fed on young dinosaurs

Mesozoic mammals are commonly portrayed as shrew- or rat-sized animals that were mainly insectivorous, probably nocturnal and lived in the shadow of dinosaurs. The largest known Mesozoic mammal represented by substantially complete remains is Repenomamus robustus, a triconodont mammal from the Lower Cretaceous of Liaoning, China. An adult individual of R. robustus was the size of a Virginia opossum. Here we report a new species of the genus, represented by a skeleton with most of the skull and postcranium preserved in articulation. The new species is 50% larger than R. robustus in skull length. In addition, stomach contents associated with a skeleton of R. robustus reveal remains of a juvenile Psittacosaurus, a ceratopsian dinosaur. Our discoveries constitute the first direct evidence that some triconodont mammals were carnivorous and fed on small vertebrates, including young dinosaurs, and also show that Mesozoic mammals had a much greater range of body sizes than previously known. We suggest that Mesozoic mammals occupied diverse niches and that some large mammals probably competed with dinosaurs for food and territory.     

Neuropeptide Y functions as a neuroproliferative factor

Neuropeptide Y (NPY) has a number of functions in mammalian physiology. Here we identify a role for NPY in promoting proliferation of postnatal neuronal precursor cells. NPY is synthesized in the postnatal olfactory epithelium by sustentacular cells, previously proposed to function only in structural support. Mice with a targeted deletion of NPY contain half as many dividing olfactory neuronal precursor cells as do controls. Furthermore, NPY-deficient mice develop significantly fewer olfactory neurons by adulthood. NPY acts on multipotent neuronal precursor or basal cells to activate rapidly and transiently the extracellular signal-regulated kinase (ERK)1/2 subgroup of mitogen-activated protein kinases. The NPY Y1 receptor subtype appears to mediate this effect. The ability of NPY to induce neuronal precursor proliferation is mediated by protein kinase C (PKC), indicating an upstream PKC-dependent activation of ERK1/2. These results indicate that NPY may regulate neuronal precursor proliferation in the adult mammal.     

黄斑星天牛种群消长动态研究

文章用生物学、生态学的基本方法研究了黄斑星天牛在林间的种群消长动态。结果表明,在新疆伊犁地区,黄斑星天牛在5月中下旬开始羽化,6月20日羽化达到高峰期,8月底成虫羽化趋于结束,雌成虫6月初开始产卵,7月上旬产卵达到高峰,6月下旬卵开始孵化,幼虫其长达300余天,蛹期约15天,其生活隐蔽,成活率高。最后指出适宜的气候环境、特殊的栽植格局以及天敌数量、种类不足是导致黄斑星天牛发生、繁殖、扩散的重要因素。     

Transitional mammalian middle ear from a new Cretaceous Jehol eutriconodont

The transference of post-dentary jaw elements to the cranium of mammals as auditory ossicles is one of the central topics in evolutionary biology of vertebrates. Homologies of these bones among jawed vertebrates have long been demonstrated by developmental studies; but fossils illuminating this critical transference are sparse and often ambiguous. Here we report the first unambiguous ectotympanic (angular), malleus (articular and prearticular) and incus (quadrate) of an Early Cretaceous eutriconodont mammal from the Jehol Biota, Liaoning, China. The ectotympanic and malleus have lost their direct contact with the dentary bone but still connect the ossified Meckel's cartilage (OMC); we hypothesize that the OMC serves as a stabilizing mechanism bridging the dentary and the detached ossicles during mammalian evolution. This transitional mammalian middle ear narrows the morphological gap between the mandibular middle ear in basal mammaliaforms and the definitive mammalian middle ear (DMME) of extant mammals; it reveals complex changes contributing to the detachment of ear ossicles during mammalian evolution.     

Magnetostratigraphy of Late Cenozoic fossil mammals in the northeastern margin of the Tibetan Plateau

~~Magnetostratigraphy of Late Cenozoic fossil mammals in the northeastern margin of the Tibetan Plateau~~~~     

哺乳动物克隆的研究进展

哺乳动物体细胞克隆是20世纪末生命科学领域最引人注目的高新技术,该技术在农业、生物学和医药等方面具有广泛的应用前景。近年来克隆技术发展迅速,多种哺乳动物相继克隆成功,但也存在着克隆效率太低、克隆动物表型正常而实质异常等问题。本文在近年来克隆技术研究的基础上,对克隆的概念、研究历史以及克隆的方法、过程进行了综述,展望了克隆的意义及克隆动物的应用前景,分析了目前克隆技术尚存在的问题,并提出了解决这些问题的关键。     

Tribosphenic mammal from the North American Early Cretaceous

The main groups of living mammals, marsupials and eutherians, are presumed to have diverged in the Early Cretaceous, but their early history and biogeography are poorly understood. Dental remains have suggested that the eutherians may have originated in Asia, spreading to North America in the Late Cretaceous, where an endemic radiation of marsupials was already well underway. Here I describe a new tribosphenic mammal (a mammal with lower molar heels that are three-cusped and basined) from the Early Cretaceous of North America, based on an unusually complete specimen. The new taxon bears characteristics (molarized last premolar, reduction to three molars) otherwise known only for Eutheria among the tribosphenic mammals. Morphometric analysis and character comparisons show, however, that its molar structure is primitive (and thus phylogenetically uninformative), emphasizing the need for caution in interpretation of isolated teeth. The new mammal is approximately contemporaneous with the oldest known Eutheria from Asia. If it is a eutherian, as is indicated by the available evidence, then this group was far more widely distributed in the Early Cretaceous than previously appreciated. An early presence of Eutheria in North America offers a potential source for the continent's Late Cretaceous radiations, which have, in part, proven difficult to relate to contemporary taxa in Asia.     

A Cretaceous symmetrodont therian with some monotreme-like postcranial features

A new spalacotheriid mammal preserved with a complete postcranium and a partial skull has been discovered from the Yixian Formation of Liaoning, China. Spalacotheroid symmetrodonts are relatives to modern therians (combined group of marsupials and placentals) and are characterized by many skeletal apomorphies of therians. But unlike the closely related spalacotheroids and living therians, this new mammal revealed some surprisingly convergent features to monotremes in the lumbar vertebrae, pelvis and hindlimb. These peculiar features may have developed as functional convergence to locomotory features of monotremes, or the presence of lumbar ribs in this newly discovered mammal and their absence in its close relatives might be due to evolutionary developmental homoplasy. Analysis including this new taxon suggests that spalacotheroids evolved earlier in Eurasia and then dispersed to North America, in concordance with prevailing geodispersal patterns of several common mammalian groups during the Early Cretaceous period.     

湖南省壶瓶山自然保护区兽类多样性研究

壶瓶山自然保护区已发现兽类动物55训,隶属于8目23科,其中古北种13种,占23．6％,东洋种42种,占76．4％,有一种区系不明,区系成份接近于华南区系,本对保护区内的兽类动物多样性与保护现状进行了分析,并提出了保护建议。     

光催化氧化-生物法处理有机磷农药废水

探讨了“磁性颗粒负载型TiO2”用于光催化氧化-生物工艺,处理有机磷农药废水的可行性。试验结果表明,难降解废水经80min光催化氧化后,在生物段的COD去除率可达85％以上;在光催化预处理阶段生成的中间产物(对硝基苯酚和磷酸三乙酯)对后续生物处理会产生特别严重的影响,因此适当的光催化预处理程度是保证该工艺能够经济、高效运行的关键。     

Application of a nuclear localization signal gene in transgene mice

Efficient gene transfer by cytoplasm co-injection will offer a powerful means for transgenic animals. Using co-injection in cytoplasm, two independent gene constructs, including bovine α-s1-casein-hG-CSF and a mammal expression vector expressing a nuclear localization signal (mNLS), were introduced into fertilized mouse eggs. The target gene construct was docked into host nucleus probably by the nuclear localization signal. Transgene mice have been obtained at 58% (29/50) of integration ratio. Expression level of the positive transgene mice was detected by Western blotting. Maximal expression of human G-CSF was estimated about 540 mg/L of milk. The expression ratio was up to 75% (9/12). The results here have important practical implications for the generation of mammary gland bioreactors and other transgene studies. Co-injection of a target gene with an expression vector of a mammal nuclear localization signal by cytoplasm appears to be a useful, efficient and easy strategy for generating transgenic animals, which may be able to substitute the routine method of pronucleus-injection of fertilized eggs.     

何首乌提取物对哺乳动物皮肤稳态的影响

目的：研究何首乌提取物对哺乳动物皮肤稳态的影响。方法：采用何首乌提取物，通过皮肤外敷试验，以皮肤角质层水分含量和角质细胞脂褐素含量为指标，观察对哺乳动物皮肤的稳态的作用，结果，何首乌提取物能有效提高皮肤角质层水分含量，降低角质细胞脂褐素含量，结论：何首乌提取物对皮肤的渗透屏障起重要作用。     

污水处理过程的模糊参数自校正控制器设计

针对城市污水生物处理过程存在的本质的非线性特性,采用了基于神经网络的模糊自校正方法的控制策略,同时为了提高控制的精度,比较了各种不同的隶属度函数对控制误差的影响。仿真实验结果表明,通过本方法设计的控制器可以获得满意的控制效果。     

竹子发育生物学研究进展

尽管人们利用竹子资源的历史可以追溯到7 000年以前,但直到18世纪后期人们才真正认识到竹子是禾本科植物中一个特殊的类群。现代植物分类的奠基人林奈在《植物种志》(Species Plantarum)一书中,还只是将全世界的竹子归为芦竹属的一个种Arundo arbor,直到1789年,竹子才从芦竹属(Arundo)独立出来,成立了簕竹属(Bambusa)。自竹类被认识到有别于其他禾本科植物至今,有关竹子的形态学、解剖学、系统分类学、生理学、生态学、细胞学、遗传学以及分子生物学等,已经有大量的研究报道,但对竹类植物各个器官的发生、发育和衰老过程尚缺乏系统的研究。笔者对竹类植物的根、地下茎、竹秆、竹叶和生殖器官发育生物学的研究进行了回顾与总结,分析了目前竹子发育生物学领域有待继续深入研究的问题。建议竹子发育生物学的研究应关注细胞分裂、分化和形态建成的全过程,明确整个过程中生理生化指标的变化规律,进而揭示植物发育全过程每个环节的信号转导途径和基因调控网络。     

树突状细胞与妇科肿瘤的免疫治疗

树突状细胞(DC)是目前所知机体内功能最强的专职抗原提呈细胞,可在体内外向T细胞提呈抗原并诱发CTL反应,在抗肿瘤免疫中发挥重要作用.近年采用DC疫苗进行抗肿瘤治疗已成为当今肿瘤生物治疗领域备受关注的焦点之一.针对DC抗肿瘤机制、妇科肿瘤的免疫逃逸及在妇科肿瘤上的应用进行了研究.     

Nuclear export dynamics of RNA-protein complexes

The central dogma of molecular biology - DNA makes RNA makes proteins - is a flow of information that in eukaryotes encounters a physical barrier: the nuclear envelope, which encapsulates, organizes and protects the genome. Nuclear-pore complexes, embedded in the nuclear envelope, regulate the passage of molecules to and from the nucleus, including the poorly understood process of the export of RNAs from the nucleus. Recent imaging approaches focusing on single molecules have provided unexpected insight into this crucial step in the information flow. This review addresses the latest studies of RNA export and presents some models for how this complex process may work.