一种快速的胚胎组织总RNA的提取方法

简要介绍一种改进的提取人体器官组织总RNA的方法,该方法具有费用低,快速简便,重复性好的优点,提取的RNA无DNA等污染物,完全能满足基因表达研究的需要。     

MyoD-positive myoblasts are present in mature fetal organs lacking skeletal muscle.

The epiblast of the chick embryo gives rise to the ectoderm, mesoderm, and endoderm during gastrulation. Previous studies revealed that MyoD-positive cells were present throughout the epiblast, suggesting that skeletal muscle precursors would become incorporated into all three germ layers. The focus of the present study was to examine a variety of organs from the chicken fetus for the presence of myogenic cells. RT-PCR and in situ hybridizations demonstrated that MyoD-positive cells were present in the brain, lung, intestine, kidney, spleen, heart, and liver. When these organs were dissociated and placed in culture, a subpopulation of cells differentiated into skeletal muscle. The G8 antibody was used to label those cells that expressed MyoD in vivo and to follow their fate in vitro. Most, if not all, of the muscle that formed in culture arose from cells that expressed MyoD and G8 in vivo. Practically all of the G8-positive cells from the intestine differentiated after purification by FACS. This population of ectopically located cells appears to be distinct from multipotential stem cells and myofibroblasts. They closely resemble quiescent, stably programmed skeletal myoblasts with the capacity to differentiate when placed in a permissive environment.     

Ultrastructural studies of dorsal ciliated organs in Spionidae (Annelida: Polychaeta)

The distribution and structural components of dorsal ciliated organs (dco) in 15 species of the Spionidae were studied by scanning- and transmission electron microscopy. Based on the distribution patterns of dco, the investigated species are divided into four non-systematic groups: (I) paired anterior dco, (II) paired dco extending posteriorly for several chaetigers, (III) paired anterior dco in combination with unpaired, sexually dimorphic, metameric dco, and (IV) paired anterior dco in combination with paired, metameric dco. Previous ultrastructural studies have only included species possessing organs of groups I and III. In the present investigation the ultrastructure of dco found in Laonice bahusiensis and Spio cf. filicornis (species with dco of groups II and IV) is studied in an attempt to consider their homology. Apart from the metameric dco of group III, similarities of the cellular components of the dco indicate a homology to nuchal organs.     

墨兰的解剖学研究

运用石蜡切片法和扫描电镜技术,对墨兰营养器官和生殖器官进行了研究。结果表明墨兰叶片表面具较厚的角质层。气孔多为四轮列型,分布在下表皮,叶肉没有海绵组织和栅栏组织的分化,但叶尖部和叶中部中脉附近的叶肉细胞常伸长,类似栅栏组织细胞,平行脉,外韧型维管束,在假鳞茎中,维管束散生在基本组织中,根具根被,皮层和维管柱三部分,花被各部分基本结构均相似,唇瓣和合蕊柱的表皮为腺表皮,具花柱道,三心皮雌蕊,一室,侧膜胎座,四合花粉,表面无纹饰,蒴果。     

乌龟白细胞发育过程的观察

通过对乌龟骨髓、脾脏、肝脏等几种组织涂片的观察研究,发现骨髓与脾脏是乌龟的主要造血器官;白细胞的发育过程大致经过三个阶段,即原始阶段、幼稚阶段、成熟阶段。着重描述了各个阶段细胞的形态特征,并对乌龟白血细胞的发育及命名等问题作了初步探讨。     

The fine structure of the type 2 cells in the Malpighian tubules of the stick insect,Carausius morosus

Summary Type 2 cells, or mucocytes, are present in both inferior and superior Malpighian tubules ofCarausius morosus and are concentrated towards the distal ends of the main urine-secreting parts. They are absent from the proximal few millimetres of the main part and from the distal specialised regions of the tubules. They possess numerous Golgi bodies and abundant granular E. R., which is consistent with the hypothesis that they secrete mucus. However, they possess basal infoldings and apical microvilli suggesting that they may transport substances across the tubule wall. It is suggested that they perform both functions. Reabsorption of ions or water could precipitate solid components of the urine (e.g., uric acid). Mucus may be important in nucleation of crystalline material and also prevent abrasion of the brush border.This investigation formed part of a thesis for the degree of Ph.D. in the University of Newcastle upon Tyne. It is a pleasure to thank Professor J. Shaw for his advice and encouragement and the Science Research Council for financial support.     

Culture-independent analysis of an endophytic core microbiome in two species of wheat: Triticum aestivum L. (cv. ‘Hondia’) and the first report of microbiota in Triticum spelta L. (cv. ‘Rokosz’)

The main goal of the study was to determine the structure of endophytic bacteria inhabiting different parts (endosperm, germ, roots, coleoptiles, and leaves) of two wheat species, Triticum aestivum L. (cv. ‘Hondia’) and Triticum spelta L. (cv. ‘Rokosz’), in order to provide new knowledge about the stability and/or changeability of the core microbiome in different plant organs. The endophytic core microbiome is associated with plants throughout their whole life cycle; however, plant organs can determine the actual endophytic community. Therefore, next generation sequencing with MiSeq Illumina technology was applied to identify the endophytic microbiome of T. aestivum and T. spelta. Bioinformatic analyses were performed with the use of the DADA2(1.8) package and R software (3.5.1).It was demonstrated that wheat, which is an important crop plant, was associated with beneficial endophytic bacteria inside the endosperms, germs, roots, leaves, and coleoptiles. Importantly, for the first time, biodiversity was recognized in the coleoptiles of the investigated wheat species. Flavobacterium, Pseudomonas and Janthinobacterium were shown to be common genera for both tested wheat cultivars. Among them, Pseudomonas was found to be the only endophytic genus accompanying both wheat species from the endosperm stage to the development of the leaf. Paenibacillus was recognized as a core genus for the ‘Hondia’ cv., whereas Pedobacter and Duganella constituted the core microbiome in the ‘Rokosz’ cv. In addition, the first insight into the unique and yet unrecognized endophytic microbiome of T. spelta is presented.     

Morphology of the female reproductive organs of the African lion (Panthera leo)

The topography and splanchnology of the reproductive organs of the African lioness were studied and described in situ and after removal. The kidneys were located far caudally in relation to the thirteenth ribs. The suspensory ligament was very well developed, originated in a fan‐like manner from the dorsolateral abdominal wall lateral to the kidney and extended up to a few centimetres cranial to the kidney. The proper ligament of the ovary as well as the round ligament was well developed. The round ligament inserted on the medial femoral fascia. The left ovary was bigger than the right. The ovarian bursa had a short mesosalpinx that did not cover any part of the ovary and the fimbriae extended along the entire length. The urethral tuberculum as well as the urethral crest were well developed. The left uterine horn was longer than the right. The uterine tube was found to open directly into the tip of the uterine horn and not onto a papilla. The reproductive organs of the lioness resembled those of the domestic cat and dog but with some major differences.     

The sensory basis of trail following in some lepidopterous larvae: contact chemoreception

ABSTRACT. . Caterpillars of the genus Malacosoma follow trails of the chemical 5-beta-cholestane-3,24-dione, but nothing is known of how they perceive this compound, or more generally about the sensory basis of trail following in caterpillars. By selective ablations of chemosensory organs we show that, in Malacosoma , the trail chemical is perceived by the maxillary palpi. In another lepidopteran species, Yponomeuta cagnagellus , the palpi are needed to discriminate their own trails from a trail of Malacosoma. Malacosoma larvae also lose their specificity for conspecific trails when their palpi are ablated. Volatile cues evidently do not play a role in trail-following behaviour, since neither Malacosoma nor Yponomeuta can orient on a trail covered with fine nylon mesh. These data indicate that for Malacosoma , and probably also for Yponomeuta , contact chemoreception mediated by the maxillary palpi is the primary mode of pheromone perception. The evolution of receptor sensitivity to trail chemicals in caterpillars is discussed.