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61.
Camillo Peracchia 《The Journal of cell biology》1974,61(1):107-122
Cross-sectioned and cross-fractured crayfish axons display regions in which axon and Schwann cell surface membranes are regularly curved and project into the axoplasm. At these regions (projections) the two membranes run precisely parallel, separated by a gap of 130–140 Å. Longitudinal fractures through the axons expose the inner fractured surface of either the internal (face A) or the external (face B) leaflet of axon and adjacent Schwann cell surface membranes. On both membranes the projections appear as elongated structures oriented with the long axis parallel to the long axis of the nerve fiber. On face A of the axon surface membrane they are seen as elongated indentations 0.5–1.2-µm long, 0.12–0.15-µm wide. The indentations contain parallel chains of globules. The chains repeat every 120–125 Å and are oriented obliquely in such a way that if one looks at the axon surface from the extracellular space, the axis of the chains is skewed counterclockwise to the long axis of the indentations by an acute angle (most often 55–60°). The globules repeat along the chain every 80–85 Å. Globules of adjacent chains are in register in such a way that the axis on which globules of neighboring chains are aligned forms an angle of 75–85° with the axis of the chains. The complex structure can be defined as a globular array with a rhomboidal unit cell of 80–85 x 120–125 Å. On face B of the axon surface membrane the complementary image of these structures is seen. The projections of the Schwann cell surface membrane also contain groupings of globules; however, these differ from those in the axonal projections in size, pattern of aggregation, and fracture properties. Several possible interpretations of the meaning of these membrane specializations could be proposed. They could be: (a) structures involved in the mechanism of excitation, (b) regions of presumed metabolic couplings, and (c) areas of cell-to-cell adhesion. 相似文献
62.
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64.
Miletti-González KE Murphy K Kumaran MN Ravindranath AK Wernyj RP Kaur S Miles GD Lim E Chan R Chekmareva M Heller DS Foran D Chen W Reiss M Bandera EV Scotto K Rodríguez-Rodríguez L 《The Journal of biological chemistry》2012,287(23):18995-19007
CD44 is a multifunctional cell receptor that conveys a cancer phenotype, regulates macrophage inflammatory gene expression and vascular gene activation in proatherogenic environments, and is also a marker of many cancer stem cells. CD44 undergoes sequential proteolytic cleavages that produce an intracytoplasmic domain called CD44-ICD. However, the role of CD44-ICD in cell function is unknown. We take a major step toward the elucidation of the CD44-ICD function by using a CD44-ICD-specific antibody, a modification of a ChIP assay to detect small molecules, and extensive computational analysis. We show that CD44-ICD translocates into the nucleus, where it then binds to a novel DNA consensus sequence in the promoter region of the MMP-9 gene to regulate its expression. We also show that the expression of many other genes that contain this novel response element in their promoters is up- or down-regulated by CD44-ICD. Furthermore, hypoxia-inducible factor-1α (Hif1α)-responsive genes also have the CD44-ICD consensus sequence and respond to CD44-ICD induction under normoxic conditions and therefore independent of Hif1α expression. Additionally, CD44-ICD early responsive genes encode for critical enzymes in the glycolytic pathway, revealing how CD44 could be a gatekeeper of the Warburg effect (aerobic glycolysis) in cancer cells and possibly cancer stem cells. The link of CD44 to metabolism is novel and opens a new area of research not previously considered, particularly in the study of obesity and cancer. In summary, our results finally give a function to the CD44-ICD and will accelerate the study of the regulation of many CD44-dependent genes. 相似文献
65.
Chiara Sandri Francesca Caccavari Donatella Valdembri Chiara Camillo Stefan Veltel Martina Santambrogio Letizia Lanzetti Federico Bussolino Johanna Ivaska Guido Serini 《Cell research》2012,22(10):1479-1501
During developmental and tumor angiogenesis, semaphorins regulate blood vessel navigation by signaling through plexin receptors that inhibit the R-Ras subfamily of small GTPases. R-Ras is mainly expressed in vascular cells, where it induces adhesion to the extracellular matrix (ECM) through unknown mechanisms. We identify the Ras and Rab5 interacting protein RIN2 as a key effector that in endothelial cells interacts with and mediates the pro-adhesive and -angiogenic activity of R-Ras. Both R-Ras-GTP and RIN2 localize at nascent ECM adhesion sites associated with lamellipodia. Upon binding, GTP-loaded R-Ras converts RIN2 from a Rab5 guanine nucleotide exchange factor (GEF) to an adaptor that first interacts at high affinity with Rab5-GTP to promote the selective endocytosis of ligand-bound/active β1 integrins and then causes the translocation of R-Ras to early endosomes. Here, the R-Ras/RIN2/Rab5 signaling module activates Rac1-dependent cell adhesion via TIAM1, a Rac GEF that localizes on early endosomes and is stimulated by the interaction with both Ras proteins and the vesicular lipid phosphatidylinositol 3-monophosphate. In conclusion, the ability of R-Ras-GTP to convert RIN2 from a GEF to an adaptor that preferentially binds Rab5-GTP allows the triggering of the endocytosis of ECM-bound/active β1 integrins and the ensuing funneling of R-Ras-GTP toward early endosomes to elicit the pro-adhesive and TIAM1-mediated activation of Rac1. 相似文献
66.
Camillo De Camillis Jean-Christophe Bligny David Pennington Balázs Pályi 《The International Journal of Life Cycle Assessment》2012,17(4):511-515
Purpose
This paper illustrates the consensus achieved by the members of the European Food Sustainable Consumption and Production Round Table Working Group 1 in their second scientific workshop held in the European Commission’s Joint Research Centre site in Ispra, Italy on July 5–7, 2011. This workshop came after having run a detailed analysis, of data gaps and of methodologies, for the environmental assessment of food and drink products. In particular, the aim of this workshop was to reach consensus amongst key stakeholders on those approaches found diverging across methodologies and on which the forthcoming protocol for the ENVIronmental assessment of FOOds and Drinks (ENVIFOOD Protocol) is expected to provide guidance to the sector. 相似文献67.
Immune-mediated beta-cell destruction in vitro and in vivo-A pivotal role for galectin-3 总被引:2,自引:0,他引:2
68.
Thymelaea velutina (Thymelaeaceae) is a unique dioecious and heterocarpic shrub, each female producing both dry and fleshy fruits. It is endemic
to the Balearic Islands (western Mediterranean) and has suffered an important regression in recent decades, especially due
to habitat loss. It lives in coastal areas, mainly in dunes, but a few populations occur up to 1300 m in the mountains of
Mallorca. In the present study, we examined its breeding system and pollen vectors, determined whether seed production is
pollen-limited, and quantified the relative importance of different insect visitors at coastal and mountain sites. Selective
exclusions showed no differences between populations in the relative importance of insects and wind as pollen vectors. Pollen
was limiting at both populations, though not consistently in time. Flowers of T. velutina were visited mostly by generalist insects, and species composition and abundance of flower visitors varied both in space
and time. The flowering period is about a month later in the mountain than in the dune, and this results in a higher frequency
of insect visits to plants in the mountain due to the higher insect abundance; insects were also more diverse in the mountain,
although they visited a proportionally lower number of flowers than in the dune. Despite this spatio-temporal variation in
the frequency of insect visits and in the importance of a particular insect group, the ambophilous system in this species
(previously described as anemophilous) ensures a relatively high fruit set at the two different sites. 相似文献
69.
70.
Camillo Secchi Mariagiulia Cagnasso Giacomo Resmi Pier Antonio Biondi 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1978,145(2):257-264
A unit is described to regulate the electrical power delivered to an isoelectric focusing cell. The device consists in a resistance set, in series with a power supply, which can be adjusted to a suitable resistance value in order to permit only minor changes in wattage. Simultaneous monitoring of voltage and current is also carried out with a pen-recorder adaptor.The improvements in operative conditions achieved by these means are tested by the fractionation of mammalian growth hormones. 相似文献