Range Of Animal Cells Research Articles

The Expression Patterns of Septin-9 After Traumatic Brain Injury in Rat Brain

Septins are a novel group of GTPases, which are first identified in yeast and more recently found in a wide range of animal cells. Septin-9, a novel septin family member, is expressed ubiquitously and involved in an increasing number of signaling cascades. However, information regarding its distribution and possible function in the central nervous system (CNS) is limited. In this study, western blot analysis and immunohistochemistry showed a significant upregulation of Septin-9 in the ipsilateral peritrauma cortex compared with the sham group. Immunofluorescent labeling indicated that Septin-9 was localized strikingly in the cytoplasm of neurons, but not astrocytes and oligodendrocytes. The co-localization of Septin-9 and active caspase-3 was also examined in the ipsilateral cortex. In addition, the expression patterns of active caspase-3 were parallel with that of Septin-9. Quantitative real-time RT-PCR also was used to detect Seption-9 mRNA level. Based on our data, we speculated that traumatic brain injury may be a stimulus to induce the Septin-9 expression, and Septin-9 might play an important role in the pathophysiology process in the CNS after traumatic brain injury. Taken together, this is the first description of Septin-9 expression changes during the central nervous system lesion and repair, but further studies are needed to understand the cell signaling pathway which can direct the exact role of Septin-9 following traumatic brain injury.

Molecular genetic analysis of V-ATPase function in Drosophila melanogaster.

V-ATPases are phylogenetically widespread, highly conserved, multisubunit proton pumps. Originally characterised in endomembranes, they have been found to energise transport across plasma membranes in a range of animal cells and particularly in certain epithelia. While yeast is the model of choice for the rapid generation and identification of V-ATPase mutants, it does not allow their analysis in a plasma membrane context. For such purposes, Drosophila melanogaster is a uniquely suitable model. Accordingly, we have cloned and characterised genes encoding several V-ATPase subunits in D. melanogaster and, using P-element technology, we have succeeded in generating multiple new alleles. Reporter gene constructs reveal ubiquitous expression, but at particularly high levels in those epithelial thought to be energised by V-ATPases, and several of the alleles have lethal recessive phenotypes characterised by epithelial dysfunction. These results, while providing the first gene knockouts of V-ATPases in animals, also illustrate the general utility of D. melanogaster as a model for the genetic analysis of ion transport and its control in epithelia.

A monoclonal antibody raised against cytoplasmic fibrillar bundles from carrot cells, and its cross-reaction with animal intermediate filaments

ABSTRACT Carrot suspension cells contain cytoplasmic bundles of fibrils that are distinct from F-actin and microtubules and have some of the characteristics of intermediate filaments. In characterizing these fibrillar bundles further, we have raised a monoclonal antibody against them. This anti-fibrillar bundle antibody (AFB) immunoblots vimentin from a range of animal cells and tissues, as well as glial fibrillary acidic protein in brain and desmin in BHK fibroblasts, which are representatives of the type III intermediate filaments. Immunofluorescence staining of PtK2 cells indicates that AFB recognizes a network co-distributing with cytoplasmic microtubules. When this co-alignment is disturbed with the anti-microtubule agent, colcemid, the AFB staining segregates with the collapsed perinuclear whorls of vimentin. In carrot, AFB immunoblots the major bundle proteins but not plant tubulin. In plant as in animal cells, AFB immunofluorescently labels antigens that co-distribute with microtubules. In onion cells (which, unlike carrot, do not possess paracrystalline arrays of fibrils) AFB labels all four microtubule arrays throughout the cell cycle. The antigens do not, however, collapse around the spindle poles during mitosis. Double immunofluorescence, using anti-dog brain tubulin, indicates that the FB antigen is more diffusely distributed than tubulin; it is patchy and co-alignment is not exact, particularly during early preprophase band formation. Antigens in detergent-insoluble fibrils of carrot cells therefore exist both in animal type III intermediate filaments (IF), and in a more dispersed, microtubule-associated manner in onion meristematic cells. This constitutes an independent line of evidence for the existence of IF antigens in plants.

Studies on the Golgi Apparatus in Gland-Cells. II. Glands producing lipoidal Secretions— the so-called Skin Glands

As a result of recent studies on secretory synthesis, the following conclusions have been reached : 1. Many gland-cells run through a regular ‘secretory cycle’, beginning with a small cell devoid of secretory granules, progressing through a period in which large numbers of granules are produced and terminating in an act of extrusion of the granules. The cycle may or may not be repeated according to the nature of the cell. 2. The Golgi apparatus is from the beginning present in all kinds of secretory cells, and during the secretory cycle becomes very greatly hypertrophied, establishing a volume in rough relation to that of the secretory products. 3. The topography and behaviour of the apparatus is different in different kinds of glands, but is roughly divisible into three general types characteristic of cells which produce serous, mucous, and lipoidal secretions. 4. The secretory granules make their first appearance only within the area delimited by the Golgi apparatus. 5. In a few cases relations have been made out which indicate that the secretory granules arise in close connexion with the Golgi material. 6. It is concluded that secretory granules are differentiated by the Golgi material, but that no direct transformation of the one into the other occurs such as was claimed by some authors in the case of the mitochondria. 7. It is suggested that the Golgi material is structurally homologous throughout the range of animal cells, and that the so-called idiosomic substance, sometimes associated with it, is to be looked upon as one phase of a duplex system in which the relative development of lipoidal and idiosomic substances may undergo considerable variation. 8. It is suggested that the relation between the Golgi apparatus and secretory granules is homologous to that existing between the Golgi apparatus and the developing acrosome of the animal sperm, and that our rather complete under standing of the latter phenomenon can thus be used as a basis for interpreting the much more obscure phenomena in the gland-cell. 9. No cytological evidence of the origin of secretory products from the nucleus receives any general acceptance at the present time. The nucleus can be considered as the source of secretions only in the indirect sense that it may possibly exercise some control over the process as a whole or may collaborate with other parts of the cell system in preparing materials for the actual synthetic operations of the Golgi apparatus. 10. The establishment of the views here developed must depend finally upon further critical evidence bearing upon the exact relation which exists between individual secretory granules and the Golgi complex.