Isolation and partial characterization of human erythrocyte membrane NADH: (Acceptor) oxidoreductase

Gengliosides generally provide a small portion of the complex carbohydrate content of cell surfaces. An exception is the central nervous system where they comprise up to 5–10% of the total lipid of some membranes. This tissue is unique in that the quantity of lipid-bound sialic acid exceeds that of the protein-bound fraction. Over 30 different molecular species have been characterized to date. These range in complexity from sialosylgalactosyl ceramide with 2 sugars to the pentasialoganglioside of fish brain with 9 carbohydrate units. Virtually all cellular and subcellular fractions of brain that have been carefully examined contain gangliosides to one degree or another, but the majority of brain ganglioside is located in the neurons. Their mode of distribution within the neuron has not been entirely clarified by subcellular studies. Calculations based on reported values for axon terminal density and synaptosomal ganglioside concentration in the rat reveal that nerve endings contribute less than 12% of total cerebral cortical ganglioside. It is concluded that the plasma membranes of neuronal processes contain most of the neuronal ganglioside. These and other considerations suggest the possibility that gangliosides may be distributed over the entire neuronal surface.     

神经前体细胞表达发育性下调蛋白4在消化系统肿瘤发生中的作用

神经前体细胞表达发育性下调蛋白4(neural precursor cell expressed,developmentally down-regulated protein 4,NEDD4-1,部分文章也称NEDD4)是近年来才备受关注的肿瘤相关基因,属于E3 HECT(homologous to E6 associated protein C terminus,E6蛋白c端同源基因)泛素连接酶NEDD4样家族成员。泛素连接酶,能够参与多种蛋白质的泛素化、溶酶体及蛋白酶体的降解、胞核-胞质转位等,间接影响不同恶性肿瘤的多种信号通路。随着大量NEDD4-1与肿瘤相关实验的不断深入,目前已发现其可通过调控细胞周期、癌细胞侵袭转移、拮抗耐药性等许多途径影响肿瘤的生物学行为。在消化系统肿瘤中,NEDD4-1主要通过PTEN/PI3K/AKT、TGF-β、Hippo、LDLRAD4等多条通路促进肝细胞癌的增殖、侵袭和迁移能力;在胰腺癌中发现,NEDD4-1在PI3K/AKT信号通路中发挥癌基因作用,但在与Myc-SIRT2所形成的信号环路中,却发挥抑癌基因的作用;在胃癌和结直肠癌中,NEDD4-1所参与的信号通路与其他消化系统肿瘤均不相同,NEDD4-1能独立于PTEN/PI3K/AKT通路而发挥促进胃癌恶化、转移(EGFR信号通路)和抑制结直肠癌肿瘤生长(WNT信号通路)的作用。NEDD4-1已经成为人们治愈肿瘤的热门研究方向。本文通过系统总结NEDD4-1在不同消化系统肿瘤中的功能、信号通路和潜在抑制剂等,进行探讨NEDD4-1与不同信号通路的关系,旨为临床在癌症治疗领域提供重要的参考数据。     

Articular-surface-based automatic anatomical coordinate systems for the knee bones

Increasing use of patient-specific surgical procedures in orthopaedics means that patient-specific anatomical coordinate systems (ACSs) need to be determined. For knee bones, automatic algorithms constructing ACSs exist and are assumed to be more reliable than manual methods, although both approaches are based on non-unique numerical reconstructions of true bone geometries. Furthermore, determining the best algorithms is difficult, as algorithms are evaluated on different datasets. Thus, in this study, we developed 3 algorithms, each with 3 variants, and compared them with 5 from the literature on a dataset comprising 24 lower-limb CT-scans. To evaluate algorithms’ sensitivity to the operator-dependent reconstruction procedure, the tibia, patella and femur of each CT-scan were each reconstructed once by three different operators.Our algorithms use principal inertia axis (PIA), cross-sectional area, surface normal orientations and curvature data to identify the bone region underneath articular surfaces (ASs). Then geometric primitives are fitted to ASs, and the ACSs are constructed from the geometric primitive points and/or axes. For each bone type, the algorithm displaying the least inter-operator variability is identified. The best femur algorithm fits a cylinder to posterior condyle ASs and a sphere to the femoral head, average axis deviations: 0.12°, position differences: 0.20 mm. The best patella algorithm identifies the AS PIAs, average axis deviations: 0.91°, position differences: 0.19 mm. The best tibia algorithm finds the ankle AS center and the 1st PIA of a layer around a plane fitted to condyle ASs, average axis deviations: 0.38°, position differences: 0.27 mm.     

Role of Drosophila gene dunc-115 in nervous system

Axonal guidance signals are transduced through growth cone surface receptors to the interior leading to changes of actin dynamics and actin binding proteins, which are critical in determining the outcome of actin cytoskeleton reorganization. We report here the characterization of the Drosophila actin binding protein abLIM/Unc-115 homolog Dunc-115 and its role in the nervous system. Three Dunc-115 isoforms are identified as Dunc-115L, M and S, respectively. While Dunc-115L is a canonical homolog of Unc-115 with four LIM domains and one villin headpiece domain, Dunc-115M and S are novel isoforms without counterparts in other species. Our molecular modeling shows Dunc-115L is likely to bind to actin. Mutant analysis reveals that Dunc-115 is involved in axonal projection in both the visual and central nervous system.     

新版DELTA系统在植物分类学中的应用——以羊茅属研究为例

DELTA系统是针对分类学研究开发的综合性多功能软件包。新版DELTA系统在运行环境、程序、指令、界面、操作方式及中文字符处理等重要功能上比旧版本均有较大改进。作为国际分类学数据库数据交换标准,应用该系统可以规范分类学描述,对研究中所有常用性状进行识别和处理,自动生成各个研究对象分类学特征描述并对其进行详尽的相似性和差异性比较,对性状特征和分类单元进行注释和图像示例,将数据转换为数量分类学或分支分类学所需格式以生成树状图,自动生成检索表,建成基于本地和网络的交互式专家辅助鉴定系统等。DELTA系统作为植物分类学研究的常用手段和工具是非常适合及大有帮助的。     

Nerve growth factor: Cellular localization and regulation of synthesis

1. The role of nerve growth factor (NGF) as a retrograde messenger between peripheral target tissues and innervating sympathetic and neural crest-derived sensory neurons is supported by the observations that (a) the interruption of retrograde axonal transport has the same effects as the neutralization of endogenous NGF by anti-NGF antibodies and (b) the close correlation between the density of innervation by fibers of NGF-responsive neurons and the levels of NGF and mRNANGF in their target organs. 2. In situ hybridization experiments have demonstrated that a great variety of cells in the projection field or NGF-responsive neurons is synthesizing NGF, among them epithelial cells, smooth muscle cells, fibroblasts, and Schwann cells. 3. The temporal correlation between the growth of trigeminal sensory fibers into the whisker pad of the mouse and the commencement of NGF synthesis initially suggested a causal relationship between these two events. However, in chick embryos rendered aneural by prior removal of the neural tube or the neural crest, it was shown that the onset of NGF synthesis in the periphery is independent of neurons, and is controlled by an endogenous "clock" whose regulatory mechanism remains to be established. 4. A comparison between NGF synthesis in the nonneuronal cells of the newborn rat sciatic nerve and that in the adult sciatic nerve after lesion provided evidence for the important regulatory role played by a secretory product of activated macrophages. The identity of this product is currently under investigation.     

Direct peptide profiling of lateral cell groups of the antennal lobes of Manduca sexta reveals specific composition and changes in neuropeptide expression during development

The paired antennal lobes are the first integration centers for odor information in the insect brain. In the sphinx moth Manduca sexta, like in other holometabolous insects, they are formed during metamorphosis. To further understand mechanisms involved in the formation of this particularly well investigated brain area, we performed a direct peptide profiling of a well defined cell group (the lateral cell group) of the antennal lobe throughout development by MALDI-TOF mass spectrometry. Although the majority of the about 100 obtained ion signals represent still unknown substances, this first peptidomic characterization of this cell group indicated the occurrence of 12 structurally known neuropeptides. Among these peptides are helicostatin 1, cydiastatins 2, 3, and 4, M. sexta-allatotropin (Mas-AT), M. sexta-FLRFamide (Mas-FLRFamide) I, II, and III, nonblocked Mas-FLRFamide I, and M. sexta-myoinhibitory peptides (Mas-MIPs) III, V, and VI. The identity of two of the allatostatins (cydiastatins 3 and 4) and Mas-AT were confirmed by tandem mass spectrometry (MALDI-TOF/TOF). During development of the antennal lobe, number and frequency of ion signals including those representing known peptides generally increased at the onset of glomeruli formation at pupal Stage P7/8, with cydiastatin 2, helicostatin 1, and Mas-MIP V being the exceptions. Cydiastatin 2 showed transient occurrence mainly during the period of glomerulus formation, helicostatin 1 was restricted to late pupae and adults, while Mas-MIP V occurred exclusively in adult antennal lobes. The power of the applied direct mass spectrometric profiling lies in the possibility of chemically identifying neuropeptides of a given cell population in a fast and reliable manner, at any developmental stage in single specimens. The identification of neuropeptides in the antennal lobes now allows to specifically address the function of these signaling molecules during the formation of the antennal lobe network.