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Peripheral Cytoplasm (peripheral + cytoplasm)
Selected AbstractsCryopreservable neutrophil surrogates: Granule-poor, motile cytoplasts from polymorphonuclear leukocytes home to inflammatory lesions in vivoCYTOSKELETON, Issue 5 2006Stephen E. Malawista Abstract Cytokineplasts (CKP) are anucleate, motile, granule-poor fragments induced from polymorphonuclear leukocytes on surfaces by the brief application of heat. Derived from the peripheral cytoplasm and membranes of PMN, they retain the sensing, transducing, and effector mechanisms necessary for chemotaxis and phagocytosis, and appear to represent a functional, self-purification of the motile apparatus. Unlike their parent PMN, CKP are cryopreservable. We have shown that they can adhere to endothelial cell monolayers, open interendothelial cell junctions, and migrate to the abluminal side when stimulated by a chemoattractant. Employing an animal model, we now show that, given intravenously, they can home to an inflammatory target lesion in vivo. Cell Motil. Cytoskeleton 2006. © 2006 Wiley-Liss, Inc. [source] Preparing to move: Assembly of the MSP amoeboid motility apparatus during spermiogenesis in AscarisCYTOSKELETON, Issue 4 2005Maria Antonia Rodriguez Abstract We exploited the rapid, inducible conversion of non-motile Ascaris spermatids into crawling spermatozoa to examine the pattern of assembly of the MSP motility apparatus that powers sperm locomotion. In live sperm, the first detectable motile activity is the extension of spikes and, later, blebs from the cell surface. However, examination of cells by EM revealed that the formation of surface protrusions is preceded by assembly of MSP filament tails on the membranous organelles in the peripheral cytoplasm. These organelle-associated filament meshworks assemble within 30 sec after induction of spermiogenesis and persist until the membranous organelles are sequestered into the cell body when the lamellipod extends. The filopodia-like spikes, which are packed with bundles of filaments, extend and retract rapidly but last only a few seconds before giving way to, or converting into, blebs. Coalescence of these blebs, each supported by a dense mesh of filaments, often initiates lamellipod extension, which culminates in the formation of the robust, dynamic MSP fiber complexes that generate sperm motility. The same membrane phosphoprotein that orchestrates assembly of the fiber complexes at the leading edge of the lamellipod of mature sperm is also found at all sites of filament assembly during spermiogenesis. The orderly progression of steps that leads to construction of a functional motility apparatus illustrates the precise spatio-temporal control of MSP filament assembly in the developing cell and highlights the remarkable similarity in organization and plasticity shared by the MSP cytoskeleton and the actin filament arrays in conventional crawling cells. Cell Motil. Cytoskeleton 60:191,199, 2005 © 2005 Wiley-Liss, Inc. [source] Food plaquette digestion in the ciliated protozoan Hyalophysa chattoniINVERTEBRATE BIOLOGY, Issue 2 2001Stephen C. Landers Abstract. The digestion of food plaquettes in the ciliated protozoan Hyalophysa chattoni was analyzed by light and electron microscopy. Through the use of nigrosin as a tracer for light microscopy and polystyrene microparticles for electron microscopy, we have demonstrated that food plaquettes transform to late-stage digestive vesicles. Eventually, in the phoront, some of the late-stage vesicles merge to form larger fusion vesicles, which are retained in the peripheral cytoplasm of the ensuing feeding stage. After the feeding stage settles and encysts, these vesicles are either retained by the daughter cells or are left in the divisional cyst as residual bodies. Food plaquettes, digestive vesicles, and fusion vesicles stain positively with neutral red and acridine orange, indicating an acidic pH. These results portray a unique digestive pathway in which stored, undigested material is reorganized into larger fusion vesicles as the cell prepares for additional feeding. [source] Differential localization of laminin ,2 and integrin ,4 in primary cultures of the rat gingival epitheliumJOURNAL OF PERIODONTAL RESEARCH, Issue 1 2006Michie Tanno Objectives:, The aim of this study was to investigate the differential immunolocalization of laminin ,2 and integrin ,4 in primary cultures of the rat gingival epithelium. Methods:, The gingival epithelium was obtained from Sprague-Dawley rats and was cultured in serum-free keratinocyte growth medium (DK-SFM). Western blotting analysis, immunofluorescence, confocal laser scanning microscopy (CLSM), and immuno-gold labeling for laminin ,2 and integrin ,4 were employed. CLSM images for laminin and integrin were analyzed in horizontal (x,y axis) and in vertical (x,z axis) sections. Results:, Both laminin ,2 and integrin ,4 were detected by Western blot analysis in the gingival epithelium. Immunolocalization of laminin ,2 was distinct in the cytoplasm to form one or two irregular rings in gingival epithelial cells. By contrast, integrin ,4 was localized diffusely in the cytoplasm. F-actin (indicating actin filaments) was clearly discernible at the periphery of the cytoplasm to form a cellular fringe. In x,z axis images obtained by CLSM, laminin ,2 was recognized as large foci in the most inner portion just above the basal plasma membrane. Integrin ,4 existed in the area where F-actin was labeled surrounding the membrane. Immuno-electron microscopy showed that 10nm colloidal gold particles indicating laminin ,2 were mainly localized at the extracellular portion and in the peripheral cytoplasm, whereas integrin ,4 was distributed in the cytoplasm close to the basal plasma membrane but not in extracellular regions. Conclusions:, In primary cultures of the rat gingival epithelium, both laminin ,2 and integrin ,4 may be produced by the epithelium, and irregular rings of laminin ,2 are formed in areas where gingival cells adhere to the extracellular matrix. [source] Effects of tributyltin(IV) chloride on the gametes and fertilization of Ascidia malaca (Ascidiacea: Tunicata)APPLIED ORGANOMETALLIC CHEMISTRY, Issue 2 2003L. Villa Abstract Ascidia malaca gametes before fertilization incubated in 10,5 or 10,7,M solutions of tributyltin(IV) chloride, TBTCl, for 3,h appear highly damaged under transmission electron microscopy observation. Also, the fertilization process is affected by the compound: the damaged spermatozoa are present in the vitelline coat and the egg does not cleave. An increase of microbodies, structurally similar to peroxisomes, have been detected in the egg peripheral cytoplasm, probably in relation to their role in alleviating damage to some cellular components. The results have shown that the reproduction of ascidians under unfavourable environmental conditions is prevented. Copyright © 2003 John Wiley & Sons, Ltd. [source] | ||||||||||