bluuebunny/crossref_metadata_2025 huggingface dataset:
Preservation of the diffusible cations for secondary ion mass spectrometry. II. Artefacts in material embedded in araldite or melamine
Authors: Mentré Pascale , Escaig Françoise
Published: August 2004

Summary—

Flotation on hot water (about 60°C) which is frequently employed to stretch semithin sections on substrates for SIMS (secondary ion mass spectrometry) microscopy, is the cause of numerous artefacts. In the case of epoxy resin‐embedded tissue, one observes loss of potassium and sodium and accumulation of calcium. The relative contrast of cell nuclei in the ionic images is rapidly affected by these ion migrations. After prolonged contact with hot water, tissue becomes uniformly emissive. In the case of hydrosoluble resin‐embedded tissue, potassium and sodium do not appear to be affected by the action of water, which suggests that they are covalently bound with chelating sites buried beneath the layer of water bound to the surface of the macromolecules. Calcium accumulates, probably on widely exposed anionic sites. Moreover, the domains observed in hydrosoluble resin‐embedded tissue shrink differently according to the proportion of water removed by melamine; this can provide interesting information on the initial equilibrium between water, ion sand macromolecules. Our results seem to support the assumption that bound water should play an important role in the preservation of both macromolecular architecture and ion distributions.
The application of SIMS to nutrient tracer studies in plant physiology
Authors: Lazof Dennis , Linton Richard W. , Volk Richard J. , Rufty Thomas W.
Published: August 2004

Summary—

Current controversies in root physiology relating to the uptake and translocation of mineral nutrients are presented. The opportunities for a SIMS contribution to resolve these controversies are discussed for each of the stable isotope tracers relevant to plant nutrition. It is concluded that for all major nutrients except phosphorus there are promising stable isotope tracers. At the same time, there are challenges to overcome in each case, with respect to background levels, peak interferences and sometimes sensitivity. Techniques of tissue preparation and handling are discussed in some detail, giving attention to the special requirements of plant tissue preparation and analysis for diffusable ions. It is suggested that adapting a preparation and transfer system, designed for production of bulk frozen‐hydrated cryofractured specimens, to a secondary ion mass spectrometer would permit easy, rapid preparation. Additionally, this preparation minimizes several serious technical problems inherent to other preparative methods. Difficulties in quantitation are treated briefly, outlining some difficulties specific to plant tissue analysis. Prospects for future applications in plant mineral nutrition are evaluated, taking into account current instrumental developments.
14N and 15N imaging by SIMS microscopy in soybean leaves
Authors: Grignon Nicole , Halpern Sylvain , Gojon Alain , Fragu Philippe
Published: August 2004

Summary—

The distribution of 15N and 14N compounds in cryofixed and resin embedded sections of soybean (Glycine max L) leaves was studied by SIMS microscopy. The results indicate that, with a mass resolution M/ΔM higher than 6000, images of the nitrogen distribution can be obtained from the mapping of the two secondary cluster ions 12C14N− and 12C15N−, in samples of both control and 15N‐labeled leaves. The ionic images were clearly related to the histological structure of the organ, and allow the detection of 14N and 15N at the subcellular level. Furthermore, relative measurements of the 12C14N− and 12C15N− beams made possible the quantification of the 15N atom% in the various tissues of the leaf.
Membrane proteins involved in the adherence of Plasmodium falciparum‐infected erythrocytes to the endothelium
Authors: Sherman Irwin W , Crandall Ian , Smith Heidi
Published: August 2004

Summary— Plasmodium falciparum (human malaria) infections are characterized by the attachment of erythrocytes infected with mature stage parasites to endothelial cells lining the post‐capillary venules, a phenomenon known as sequestration. In the human body, the microvessels of the heart, lungs, kidneys, small intestine, and liver are the principal sites of sequestration. Sequestered cells that clog the brain capillaries may reduce blood flow sufficiently so that there is confusion, lethargy, and unarousable coma—cerebral malaria. This review considers what is known about the molecular characteristics of the surface proteins, that is, the red cell receptors and the endothelial cell ligands, involved in sequestration. Recent work from our laboratory on the characterization of the adhesive proteins on the surface of the P falciparum‐infected red cell, and the ligands to which they bind on human brain endothelial cells is also discussed. Finally, consideration is given to the multifactor processes involved in sequestration and cerebral malaria, as well as the possible role of ‘anti‐adhesion therapy’ in the management of severe malaria.
Reorganization of the apical cytoskeleton of uterine epithelial cells during early pregnancy in the rat: a study with myosin subfragment 1
Authors: Luxford Karen A , Murphy Christopher R
Published: August 2004

Summary— Actin filaments were identified in the epithelial cells of rat uterus following detergent extraction and decoration of microfilaments (MF) with myosin subfragment 1 (SI). MF connections with cytoplasmic organelles and the apical plasma membrane are also described. Transmission electron microscopy revealed that the regular microvilli of non‐pregnant, oestrous animals contain several decorated MF with rootlets descending into a densely filamentous terminal web. Following mating, the actin cytoskeleton was examined on days 1, 3 and 6 of pregnancy. In this period, the irregular projections that replace MV assumed an underlying, dense network of decorated MF, whilst smoother surfaces displayed few cytoplasmic filaments. At the time of blastocyst implantation, a structured terminal web was no longer present. Structural details were revealed concerning the contents of large, bleb‐like projections found on the apical surface.
Redistribution of microvilli and membrane enzymes in isolated rat proximal tubule cells
Authors: Rebelo Luisa , Carmo‐Fonseca Maria , Moura Teresa Fonseca
Published: August 2004

Summary— Isolated cells from the proximal tubule have previously been used to study specific renal physiological processes. Here we analysed the structural changes induced by mechanical isolation on rat proximal tubule cells. As major modifications we detected: 1) a redistribution of brush border microvilli, which spread out over all the cell surface immediately after isolation; 2) a rapid redistribution of the apical membrane enzyme markers aminopeptidase N and isomaltase; and 3) a striking decrease of membrane surface amplification factor. The results show that cells isolated from the proximal tubule rapidly loose their characteristic polarized membrane structure. Loss of epithelial polarity implies loss of several vectorial transports and should thus be cautiously taken into account when working with this model system.
Receptor‐mediated endocytosis of galactose and mannose exposing ligands: an electron microscopic study on adult and neonatal cultured rat hepatocytes
Authors: Dini Luciana , Lentini Alessandro , Mantile Giuditta , Massimi Mara , Devirgiliis Laura Conti
Published: August 2004

Summary— We compared the receptor‐mediated endocytosis for galactose and mannose exposing ligands in primary cultures of hepatocytes from newborn and adult rats. The endocytic pathway was revealed ultrastructurally using colloidal gold particles coupled to lactosylated bovine serum albumin and invertase. The binding activity on the cell surfaces is observed by keeping the cells at 4°C. For both ligands used, the binding capacity for hepatocytes from adult rats was greater than for neonatal cultured cells. Increasing the temperature to 37°C, we observed that the protein‐gold complexes entered the intracellular endocytic organelles. Within 5–15 min, the marker was confined in vesicles close to the cell surface and in the endosome, while after 60 min, the marker is found in lysosome‐like compartments. We found that the process of endocytosis is similar for galactose and mannose exposing ligands. The organelles involved in the process of endocytosis in newborn cultured hepatocytes are not different in shape from those of cultured cells of adult rats, but the process of internalization is slower.
Cytochalasin induces spindle fusion in the syncytial blastoderm of the early Drosophila embryo
Authors: Callaini Giuliano , Dallai Romano , Riparbelli Maria Giovanna
Published: August 2004

Summary— Microfilament integrity is needed to maintain the regular arrangement of the spindle microtubules and to guarantee the normal progression of the last syncytial mitoses in Drosophila embryo. To investigate when and how microfilaments participate in this process, we incubated permeabilized embryos with the inhibitor of actin polymerization, cytochalasin B, at different times during the nuclear cycle. Our results suggest that the correct microfilament distribution is only required for the appropriate segregation of nuclei during the 11th, 12th and 13th syncytial mitoses rather than during the 10th mitosis when the spindles are too far apart to interact. When cytochalasin B treatment was performed during the last syncytial mitoses many spindles fuse among them and the regular mitotic progression is perturbed.
Serum‐free culture of stromal and functionally polarized epithelial cells of guinea‐pig endometrium: a potential model for the study of epithelial‐stromal paracrine interactions
Authors: Mahfoudi Abderrahim , Fauconnet Sylvie , Bride Jacqueline , Beck Laurent , Remy‐Martin Jean‐Paul , Nicollier Monique , Adessi Gerard L
Published: August 2004

Summary— Stromal and glandular epithelial (GE) cells were isolated from guinea‐pig endometrium and grown to near confluency (6–8 days) in primary culture on plastic surfaces in a serum‐supplemented medium (SSM). The stromal cells were subcultured on plastic dishes and maintained for 72 h in SSM. Then SSM was replaced by a chemically defined medium (CDM) and the stromal cells grown to confluency (5–7 days). The GE cells were subcultured in CDM, on a basement membrane matrix (Matrigel) applied to permeable Millicell‐PC filters, and grown to confluency (5 days). Homogeneity of the subcultured endometrial cell populations was ascertained immunocytochemically. The filter‐cultured GE monolayers were polarized morphologically, and displayed epithelialspecific specialized structures. These monolayers had functional tight junctions as verified by a measurable transepithelial resistance. The subcultured cell populations were distinguished by an analysis of their cellular and secretory proteins after labelling with [35S]‐methionine and analysis by polyacrylamide gel electrophoresis. The filter‐cultured GE monolayers allowed identification of the proteins released vectorially in the apical or the basal secretory compartment, thus demonstrating the functional polarization of GE cells in this bicameral culture system. Within the defined conditions of this culture system, the paracrine factors released by the two endometrial cell populations as well as the interplay of stromal‐epithelial interactions and ovarian hormones could be investigated.
Adriamycin resistance is characterized by ultrastructural changes in human leukaemic K562 cells in vitro
Authors: Bobichon He´le´ne , Okiemi Marie‐Genevieve , Broglio Christine , Ploton Dominique , Dufer Jean
Published: August 2004

Summary— Ultrastructural changes associated with adriamycin (ADM) resistance have been investigated in the human K562 leukaemic cell line: sensitive K562 cells, a resistant subline cultured in the continuous presence of ADM and resistant cells without ADM Transmission electron microscopy (TEM) study revealed that K562‐resistant cells displayed ultrastructural modifications of the cell surface, chromatin and nucleolus conformation. Alterations were not directly related to the presence of adriamycin as deprivated cells exhibited modificated characters through a slow progressive recovery phenomenon.
Liver peroxisomes in newborns from clofibrate‐treated rats. I. A morphometric study of the recovery period
Authors: Stefanini Stefania , Sartori Claudia , Bernardo Antonietta , Ceru´ Maria Paola
Published: August 2004

Summary— Morphological and morphometric parameters (volume density (Vv), numerical density (NA) and mean diameter (D¯)) of newborn liver peroxisomes were measured throughout the first week of life in rats born to mothers treated with clofibrate (ethyl 2 p‐clorophenoxy isobutyrate) during the last five days of pregnancy. In control studies the same analyses were carried out in newborns from untreated rats. At birth (day 0), treated animals exhibited a proliferated, pleiomorphic peroxisomal population (higher Vv NA and D¯, and a spread distribution of profile diameter with respect to the controls). In the subsequent two days, many peroxisomes disappeared (decrease of Vv and NA to values even lower than controls), with a persisting high pleiomorphism (no change of D¯ and diameter distribution) in residual ones. Starting from day 3, and up today 6, larger peroxisomes were no longer detectable in test animals, and a significant, not pleiomorphic proliferation took place (D¯ and diameter distributions strictly comparable to the controls and progressively increasing Vv and NA). The correlation analysis validated these morphological results, from which it can be surmised that the postnatal peroxisome recovery period consists of a destructive phase followed by a proliferative one. The possible mechanism(s) of disposal of the excess of drug‐induced peroxisomes are discussed.
Liver peroxisomes in newborns from clofibrate‐treated rats. II. A biochemical study of the recovery period
Authors: Sartori Claudia , Stefanini Stefania , Cimini Annamaria , di Giulio Antonio , Ceru` Maria Paola
Published: August 2004

Summary— The fatty‐acyl‐CoAβ‐oxidation (FAO) and catalase activities, as well as membrane fluidity of liver peroxisomes of newborns from normal and clofibrate‐treated rats were studied during the recovery period, ie, throughout the first week of postnatal life. In the test animals the enzyme activities, which are significantly higher than controls at birth return to normal levels showing a somewhat different time course with FAO rapidly decreasing to control values within three days but with catalase still higher than controls at day 6. The half‐life and degradation rate (Kd) of FAO are identical to those calculated by us for the whole organelles and to those reported by others for total catalase in normal or clofibrate‐treated adult animals in the presence of catalase inhibitors. Soluble catalase shows turnover values which are similar though not identical to those of FAO, while total catalase has a very long half‐life and a low Kd. Peroxisomal membrane fluidity, as determined by fluorescence anisotropy of 1‐anilinonaphthalene‐8‐sulfonate (ANS) bound to purified peroxisomal fractions is higher in tests than in controls, recovering normal values within 6 days. Our results demonstrate that liver peroxisomes of rats prenatally exposed to clofibrate return to control conditions within about 1 week. The turnover parameters of enzymes and the membrane fluidity values are discussed in terms of disposal mechanism(s) for the excess of induced peroxisomes.
Tenascin: a potential modulator of cell‐extracellular matrix interactions during vertebrate embryogenesis
Authors: Riou Jean‐François , Umbhauer Muriel , Shi De Li , Boucaut Jean‐Claude
Published: August 2004

Summary— Tenascin is a large oligomeric extracellular matrix (ECM) glycoprotein whose expression is highly restricted during vertebrate development. It has a characteristic hexameric quatenary structure with six arms linked to a central globular domain. Each arm contains a single polypeptide with the central globular domain formed by the covalent association of the N‐terminal ends of the six polypeptides. Tenascin first appears during development, associated with the neural crest cell migration pathways of mammalian, avian and amphibian embryos. During later development, it is observed at sites of cartilage, bone and tendon formation. Tenascin expression also occurs in defined areas in the developing nervous system and in condensing mesenchyme, in response to epithelio‐mesenchymal interactions. The function of tenascin in these different morphogenetic processess is not yet clearly understood. Tenascin can promote neurite outgrowth in vitro and can inhibit cell interactions with fibronectin. Results based on antibody mapping and molecular cloning indicate that these properties involve two distinct cell binding sites. Together with its highly regulated expression in the embryo, these properties suggest that tenascin plays a key role in the control of cell migration and differentiation during development.
Cloning and sequencing of a 24‐kDa Trypanosoma cruzi specific antigen released in association with membrane vesicles and defined by a monoclonal antibody
Authors: Ouaissi Ali , Aguirre Tania , Plumas‐Marty Béatrice , Piras Marta , Schöneck Ralph , Gras‐Masse Hélène , Taibi Ali , Loyens Marc , Tartar André , Capron André , Piras Romano
Published: August 2004

Summary— In the present study we have used the Tcr7 monoclonal antibody (mAb) previously characterized as directed against Trypanosoma cruzi 24–25‐kDa specific antigens, both are immunogenic in man and during experimental T cruzi infections. We have demonstrated that mAb Tcr7 was able to recognize two in vitro translation products of molecular weights of 24 and 25 kDa. This suggested the holoproteic nature of these two related antigens bearing at least a common epitope and allowed us to use Tcr7 for an immunoscreening of a lambda ZAPII T cruzi cDNA library. Indeed, we have obtained several positive clones and completly sequenced the largest one which encoded theoretically for a protein of 23.7 kDa. The sequence analysis revealed a nearly perfect homology between this clone and one already described by other investigators and was shown to express a major flagellar protein of T cruzi able to bind calcium. Using different overlapping peptides derived from the sequence of the cDNA clone, we have localized the immunoreactivity of mAb Tcr7 mainly on several primary sequences present in the N‐terminal part of the sequence, suggesting that the mAb could recognize a discontinuous epitope. Moreover, the immunoelectron microscopy allowed us to show that the antigen(s) carrying the epitope reacting with mAb Tcr7 is (are) released in association with membrane vesicles which protruded from the parasite surface and the flagellar pocket. This new mechanism of antigen shedding is likely to be independent of phospholipase C‐mediated release of GPI‐anchored molecules.
Distribution of intramembranous particles and filipin‐sterol complexes in the spermatid and spermatozoon of Culex quinquefasciatus (Culicidae)
Authors: Báo Sônia N. , de Souza Wanderley
Published: August 2004

Summary— A freeze‐fracture study was carried out on spermatid and spermatozoon of the mosquito Culex quinquefasciatus. In the spermatid plasma membrane few and randomly distributed intramembranous particles were observed. In the spermatozoon the density of intramembranous particles was higher on the P‐ than on the E‐fracture face of the plasma membrane. Two populations of particles were observed. Large particles (about 15 nm in diameter) are regularly arranged in double rows as a zipper‐line, longitudinally oriented in relation to the main cell axis. These strands of particles were observed in the posterior head region, mainly associated with the E‐fracture face. Filipin was used to analyse the presence and distribution of cholesterol in thin sections and freeze‐fracture replicas. Filipin‐sterol complexes were not homogeneously distributed throughout the spermatozoon plasma membrane. They were more abundant on the P‐fracture face of the membrane lining the nuclear region. The results obtained show that Culex spermatozoon differs from those of other species in that its plasma membrane exhibits only a membrane domain, the zipper‐line, localized in the postacrosomal region.
Immunodetection of annexins 1 and 2 in ciliated cells from quail oviduct*
Authors: Chailley Bernadette , Pradel Louise‐Anne
Published: August 2004

Summary— Annexins I and 2 are Ca2+‐binding proteins related to the cytoskeletal proteins which have been reported to bind in a calcium‐dependent manner to F‐actin and phospholipids in vitro. Proteins immunologically related to the brain 37‐kDa annexin I and 36‐kDa annexin 2 were characterized by immunoblotting epithelial ciliated cells from quail oviduct. They were detected by immunofluorescence in ciliated as well as glandular cells, using antisera and purified antibodies directed against pig brain annexins. The pattern of labeling was found in the apical part of both cell types, with close membrane association. However, a wider distribution was observed in mature ciliated cells: annexins were localized in the well developed cytoskeletal meshwork in which the ciliary apparatus is tightly anchored. After immunogold labeling, annexins 1 and 2 were located in the same area as spectrin 240/235 and at the connection sites of F‐actin; both these cytoskeletals proteins were associated with the appendages of the basal body. In contrast, annexins were not detected in immature epithelial cells, while actin and spectrin were present. During ciliogenesis, the staining gradually appeared associated with the lateral and apical membranes. In this cellular model, the annexins may function during exocytosis in gland epithelial cells, where a close cytoskeleton‐membrane association is observed; moreover, in ciliated cells, a relationship between cytoskeletal elements of the terminal web and annexins may exist.
Cyclin B is associated with centrosomes in Drosophila mitotic cells
Authors: Debec Alain , Montmory Colette
Published: August 2004

Summary—

We have studied by way of confocal laser scanning microscopy the subcellular localization of cyclin B in Drosophila‐cultured cells and report here evidence that a part of the cyclin B cell pool is closely associated with the centrosome. This cyclin B centrosomal signal is strong in prophase and metaphase but disappears during anaphase. Moreover, the signal is absent in the acentriolar Drosophila cell line 1182‐4. These results put forward additional arguments suggesting that the centrosome plays an important role in the control of the cell cycle.
Attachment of Madin‐Darby canine kidney cells to extracellular matrix: role of a laminin binding protein related to the 37/67 kDa laminin receptor in the development of plasma membrane polarization
Authors: Pedro J. I. Salas , Ponce M Isabel , Brignoni Mirtha , Rodriguez Marcelo L
Published: August 2004

Summary— Madin‐Darby canine kidney (MDCK) cells have been extensively used as a model for the study of epithelial polarization. The contacts between the cell and extra‐cellular matrix (ECM) provide a signal for the polarization of apical membrane markers. In order to study the molecular basis of these contacts, MDCK cells extracts in Triton X‐100 were affinity‐purified on laminin, yielding polypeptides of 100–110 and 36 kDa, but only the second one could be enzymatically iodinated from the cell surface. This protein was also recognized by an antibody against the 37/67‐kDa laminin/elastin family of proteins. Different polypeptides were purified by the same method on type I collagen. An antibody developed against the polypeptides purified on laminin recognized also a 67‐kDa protein, blocked 125I‐laminin binding to a population of high affinity (1.5 nM KD) binding sites and caused a significant decrease in cell attachment and spreading to laminin or endogenous ECM. This antibody did not interfere with MDCK cell attachment to fibronectin or collagen matrices, but still impaired cell spreading. An apical MDCK plasma membrane protein (184 kDa), fully polarized in untreated cells, was partially mispolarized after treatment with anti‐36 kDa antibody. These results are consistent with a model of various ECM receptors operating together in these cells, and show an important role of a non‐integrin 36‐kDa laminin binding protein related to the 67‐kDa laminin receptor family in cell attachment, spreading and polarization.
Structural comparisons between the soluble and the GPI‐anchored forms of the Paramecium temperature‐specific 156G surface antigen
Authors: Azzouz Nahid , Capdeville Yvonne
Published: August 2004

Summary— Biosynthetic labelling experiments performed on P primaurelia strain 156, expressing the temperature‐specific G surface antigen, 156G SAg, demonstrated that the purified 156G SAg contained the components characteristic of a GPI‐anchor. [3h]ethanolamine, [3h]myo‐inositol, [32p]phosphoric acid and [3h]myristic acid could all be incorporated into the surface antigen. Myristic acid labelling was lost after treatment in vitro with Bacillus thuringiensis phosphatidylinositol‐specific phospholipase C (PI‐PLC). After complete digestion by pronase, a fragment containing the intact GPI‐anchor of 156G surface antigen was isolated. This fragment was shown to be hydrophobic and glycosylated and to possess an epitope found specifically in the GPI component of GPI‐anchored proteins. The role of the GPI‐tail in anchoring the 156G surface antigen into the membrane was assessed by determining that purified 156G molecules with the GPI‐anchor could be incorporated into lipid vesicles and red cell ghosts whereas the 156G molecules lacking the GPI‐anchor, as result of treatment with B thuringiensis PI‐PLC, could not. It has also been shown that the membrane‐bound form and the soluble form, obtained after cleavage of the 156G SAg lipid moiety either by an endogenous PI‐PLC or by a bacterial PI‐PLC, displayed identical circular dichroic spectra.
The plant nucleus in mycorrhizal roots: positional and structural modifications
Authors: Balestrini Raffaella , Berta Graziella , Bonfante Paola
Published: August 2004

Summary— Positional and structural modifications were demonstrated in nuclei of leek cells, after establishment of a symbiosis with two vesicular‐arbuscular fungi, Glomus versiforme and Glomus E3. By combining light, immuno‐electron microscopy and morphometry, the fungi were shown to have a direct effect on the host nuclear morphology: the effect was confined to a specific plant tissue (the cortical parenchyma) and to a moment of the fungal morphogenesis (the arbuscule). When they branch to form the complex structures called arbuscules in the inner parenchyma cells, the host nucleus migrates from the periphery of these cells towards their centre. In addition, it becomes larger and lobed, with a decondensed chromatin. A monoclonal antibody that mostly binds to the condensed chromatin revealed a significant decrease in gold labelling intensity over the nuclei of the colonized cells. These modifications suggest that the nuclear migration and the changes in chromatin organization are related to the modifications in gene expression observed during the establishment of mycorrhizal symbiosis.
Cell cycle analysis by flow cytometry: Principles and applications
Authors: Jayat Chantal , Ratinaud Marie‐Hélène
Published: August 2004

Summary— Numerous flow cytometric analyses are based on DNA content studies. We have considered firstly monoparametric cell cycle analyses, which only take DNA content into account, but are sometimes of limited interest. Then, we have presented multiparametric analyses, which can be used to improve cycle phase identification by taking simultaneously into account DNA and other cellular components, or by considering some events occurring during cell cycle. Finally, we have discussed monoparametric and multiparametric cell cycle analysis interest in various application fields, particularly in pharmacology, toxicology, tumoral pathology and higher plant system studies.
Analysis and sorting of chromosomes by flow cytometry: New trends
Authors: Métézeau Philippe , Schmitz Annette , Frelat Gerard
Published: August 2004

Summary— Flow cytogenetic is widely used since 1975, and essentially contributes to caryotype analysis and chromosome sorting. The principles of experimentation and its possibilities and limitations are now well known. Recently several new technologies have appeared. What attitude should the cytometrist adopt regarding PCR, microdissection of chromosomes, in situ hybridization, slit‐scan flow cytometry or image analysis?
A cytometric exercise in plant DNA histograms, with 2C values for 70 species
Authors: Marie Dominique , Brown Spencer C.
Published: August 2004

Summary— An introduction is given to the literature concerning methods and objectives for cytometric DNA analysis of plant nuclei. This area has gained relevance with applications in plant breeding and seed production industries, where laboratories unfamiliar with cytometry are adopting the method. An extensive graphical guide to interpreting DNA histograms and their problems is given. Conversely, cytometry laboratories unfamiliar with plant sciences will find herein a guide, and references, to adapt their methods to plant material. A table of 2C values reassessed by flow cytometry for 70 plant species, plus the genome composition (GC%) in many instances, is also included.
DNA content and cell cycle analysis by flow cytometry in clinical samples: Application in breast cancer
Authors: Spyratos Frédérique
Published: August 2004

Summary— Flow cytometry (FCM) analysis of cellular DNA content has become an increasingly important clinical research tool for the measurement and identification of abnormal cell populations. Examination of cellular DNA content can provide information for use in cell cycle analysis in cancer studies. Most researchers would agree that tumor cell proliferation indices should be leading candidates in the search for prognostic factors in breast cancer. FCM is certainly a powerful technique but the assignment of DNA index and synthetic phase of cycle are subject to a number of technical pitfalls which limit the accuracy and reproducibility of this information. This paper will focus on the difficulties encountered in FCM‐DNA analyses performed in a clinical context.
Flow cytometry's contribution to the measurement of cell functions
Authors: Maftah Abderrahman , Huet Olivier , Gallet Paul‐François , Ratinaud Marie‐Hélène
Published: August 2004

Summary— Flow cytometry has important advantages over conventional techniques. It is rapid, highly sensitive and allows multi‐parametric analysis and cell sorting. Potential exists for the measurement of many cell functions by flow cytometry. The technique can be used to determine cell viability, intracellular calcium and pH, membrane potential, enzyme activities, membrane fluidity and endocytosis. Numerous examples are given on the applications of flow cytometry for cell functions measurements in the fundamental and biomedical fields.
Recent advances of flow cytometry in fundamental and applied microbiology
Authors: Fouchet Pierre , Jayat Chantal , Héchard Yan , Ratinaud Marie‐Hélène , Frelat Gerard
Published: August 2004

Summary— This review focuses on the recent applications of flow cytometry (FCM) in microbiological research (1987‐mid 1992). It tries to give a scope of the important breakthroughs which occurred in this field during this period. The technical difficulties of microorganism analysis by flow cytometry is briefly appraised. The significance and the limits of the different microbial cell parameters attainable by flow analyses are systematically evaluated: light scatter for cell size and structure, fluorescence measurements for quantification of cellular components, microbial antigen detection and cell physiological activity estimation. Emphasis is given on the new technological advances which appeared in the last two years. The second part of the review is devoted to the analysis of the usefulness of flow cytometric approach in the different fields of microbiology: fundamental studies in microbial physiology, differentiation, microbial ecology and aquatic sciences, medical microbiology, parasitology, microbial pharmacology and biotechnology.
Recent applications of flow cytometry in aquatic microbial ecology
Authors: Troussellier Mare , Courties Claude , Vaquer André
Published: August 2004

Summary— Microorganisms (unicellular algae, bacteria) constitute fundamental compartments of aquatic ecosystems because of their high concentrations and activities. The evaluation and understanding of their behaviour and role raise different problems for which traditional methodologies are often inadequate, whether they refer to global or classical microscopic analyses. Flow cytometry (FCM) has been recently used to study microorganisms in aquatic environments. Although this technology is still applied on a limited scale in our field, a large number of works has been done showing that FCM seems to be a promising tool for aquatic microbial ecology. This paper summarizes, from the literature produced during the last decade and with original data obtained in our laboratory, the main questions related to the cell identification, the evaluation of cell viability, biomasses and productions and the measurements of bacterial and phytoplanktonic activities. The representativeness of sampling and observation scales is also discussed within the framework of the FCM measurements.
Reversible disassembly of transcription domains in lymphocyte nuclei during inhibition of RNA synthesis by DRB
Authors: Davis Lynn , Cadrin Monique , Brown David L. , Chaly Nathalie
Published: August 2004

Summary—

We are investigating the roles of RNA synthesis, chromatin structure and nuclear matrix organization in establishing and maintaining transcription domains, using mitogen stimulated lymphocytes as a model system. In a continuing study, the effects of the RNA polymerase inhibitor DRB and of its removal on nuclear organization have been examined by EM cytochemistry and by immunofluorescence labelling of the nuclear matrix P11, Sm and nucleolar fibrillarin antigens. Chromatin, interchromatin granules and nucleoli were extensively restructured after DRB, as were matrix antigens. According to cytochemical staining properties, the conformation of DRB‐induced condensed chromatin resembled that in partially stimulated lymphocytes. The nucleoplasmic fibrogranular RNP network appeared little altered, but the fibrillar proteinaceous interchromatinic regions, interpreted as representing the nuclear matrix in situ, were more affected. After removal of DRB, nuclei recovered the organization and transcriptional activity of controls within 8 h. These results suggest that the matrix subtending transcription domains remains stable when transcription is arrested, even though the chromatin and individual RNP components of the domains are disorganized. The data further indicate that absence of transcription is not solely accountable for the highly aggregated state of the chromatin in resting lymphocytes.
In vitro differentiation and mineralization of cartilaginous nodules from enzymatically released rat nasal cartilage cells
Authors: Sautier Jean‐Michel , Nefussi Jean‐Raphaël , Forest Nadine
Published: August 2004

Summary—

Nasal cartilage cells from 21‐day‐old rat fetuses were cultured at high density in the presence of ascorbic acid and β‐glycerophosphate over a 12‐day period. Immediately after plating, the cells exhibited a fibroblastic morphology, lost their chondrocyte phenotype and expressed type I collagen. On day 3, clusters of enlarged polygonal cells were found. These cell clusters synthetised type II collagen and formed an alcian‐blue‐positive matrix. The following days, a progressive increase in the number of cells positive for type 11 collagen was noted and, on day 8, typical cartilaginous nodules were formed. These nodules increased in size and number, spreading outward, laying down a dense matrix which mineralized. Light and electron microscopy observations of cross‐sections of nodules confirmed the cartilaginous nature of this tissue formed in vitro with typical chondrocytes embedded in a hyaline matrix. Furthermore, at the electron microscopic level, matrix vesicles were seen in extracellular matrix associated with the initiation of mineralization. Typical rod‐like crystals were present in the intercellular spaces along the collagen fibers. These results indicated that in a specific environment, dedifferentiated chondrocytes were able to redifferentiate and to form nodular structures with morphological ultrastructure of calcified cartilage observed in vivo.
Triiodothyronine influences quail myoblast proliferation and differentiation*
Authors: Marchal Sophie , Cassar‐Malek Isabelle , Pons Françoise , Wrutniak Chantal , Cabello Gerard
Published: August 2004

Summary—

The influence of triiodothyronine (T3) on avian myoblast proliferation and differentiation was studied in secondary cultures using plating densities of 2500 and 7000 cells/cm2. Culture media were depleted of T3 (control myoblasts) and increasing amounts were then added to concentrations of 0.6, 3 and 15 nM T3 (treated myoblasts). Independent of the cell density, T3 induced a dose‐related decrease in myoblast proliferation measured by cell number, doubling time and 3H‐thymidine incorporation. However, with the lower plating density, this influence was delayed, occurring only after the third day of culture for 0.6 nM T3‐treated myoblasts and simultaneous with the onset of myosin heavy chain accumulation. Moreover, when myoblasts were exposed to BrdU for 48 h, the T3 growth inhibitory effect disappeared, thus showing that this effect was clearly linked to differentiation. In addition, we have shown that T3 induced an early fusion of myoblasts: 65% of the maximal value of the fusion index was reached on day 3 in the T3‐treated cells in comparison to 25% in the control myoblasts. This hormone also enhanced accumulation of muscle‐specific proteins (connectin, acetylcholine receptors, myosin heavy chain), tested by cytoimmunofluorescence, ELISA, binding experiments and Western blot. All these results show that T3 increased myoblast differentiation through a pathway including myoblast withdrawal from the cell cycle. The influence of T3 could partly explain its previously reported positive effect on the number of muscle fibers.
Endocytic activity of male germ cells during puberty
Authors: Segretain Dominique
Published: August 2004

Summary—

It is well known that numerous germ cells degenerate during the first meiotic division and spermatid elongation is due mostly to an adverse physiological microenvironment in relation to hormonal deficiency. The present study is aimed at investigating the endocytic activity of germ cells, during the first wave of mouse spermatogenesis, using transferrin coupled to gold particles, in order to study the efficiency of this possible pathway of communication between Sertoli cells and germ cells. Labelling experiments in control animals confirmed a receptor‐mediated pathway in all germ cells during puberty. Furthermore, our morphological and quantitative data revealed that during spermatid elongation, degenerating germ cells possessed a highly developed endocytic apparatus which contained twice as many transferrin gold particles than normal adult cells. The fact that endocytosis of transferrin was increased in degenerating germ cells indicates that, most probably, germ cell degeneration during the first wave of spermatogenesis did not result from a deficiency in iron transport. The higher endocytic activity of degenerating germ cells, compared to adult control cells, could not only be the result of a simple process of plasma membrane internalization but also a complex mechanism which could be involved in the degradation of the cells.
Secretory proteins in a ciliate cell: Identification of epitopes common to numerous polypeptides
Authors: Eperon Simone , Peck Robert K. , Swiderski Barbara
Published: August 2004

Summary—

Secretory vesicles of the ciliate Pseudomicrothorax dubius, called trichocysts, are separated into > 40 proteins by two‐dimensional gel electrophoresis. The trichocyst, composed of a shaft and four arms, is in a condensed state when docked in the cell cortex, and it elongates into an extended state during exocytosis. Monoclonal antibodies (mAbs) were raised against trichocyst proteins. Their reactivities were analysed: I) on Western blots of extended, isolated trichocysts by immunolabeling; 2) on entire cells and extended trichocysts by indirect immunofluorescent binding assay (IFA); 3) on semi‐thin sectioned cells by IFA; and 4) on ultra‐thin sections of cells by immunogold labeling. mAb IV 4E5 labels major trichocyst proteins at 15–19, 22 and 24 kDa, pI 4.6−6.6. The epitope recognized by mAb IV 4E5 is common to as many as 30 proteins and suggests a family of proteins with possible sequence homology. By IFA, the shafts of extended trichocysts are labeled. The shafts of condensed trichocysts are labeled on both semi‐thin sections in Lowicryl and ultrathin sections. On semi‐thin Epon sections, the part of the trichocyst which is labeled is arm‐like. mAb VI 2D12 labels three major trichocyst proteins at 31 kDa, pI 5.0−5.4. The arms of extended trichocysts are labeled by IFA, but are only weakly labeled on ultrathin sections. The shaft of extended trichocysts is labeled by IFA, and the shaft of condensed trichocysts is labeled on ultrathin sections.
The cortical actin cytoskeleton in a Dipteran embryo: Analysis of the spatial reorganization of F‐actin aggregates during the early nuclear division cycles
Authors: Riparbelli Maria Giovanna , Dallai Romano , Callaini Giuliano
Published: August 2004

Summary—

Rhodamine phalloidin‐staining was used to study the organization of the cortical actin cytoskeleton of the early Ceratitis capitata embryo. The dynamics of the actin aggregates and their changes in distribution during the formation of the syncytial blastoderm, were followed in detail. It was found that these aggregates formed a shell‐like cluster around the interphase nuclei, and concentrated toward the poles of the mitotic apparatus when the nuclei divided. Laser scanning confocal microscopy revealed that aggregates not clustered at the poles of the mitotic apparatus were closely associated with fine fibers of a dense cytoplasmic network of actin filaments.
Psychology in Program Evaluation
Authors: Fernández-Ballesteros Rocío , Vedung Evert , Seyfried Erwin
Published: August 2004

This paper sheds light on the issue of how psychology is involved in program evaluation. Several contributions of psychology to this methodological discipline are discussed. Using examples taken from the evaluation of European human-resources programs, the authors emphasize the role of behavioral and subjective variables. Also, the paper contends that the fundamental types of use debated in the evaluation literature can be enriched and clarified if notions from psychological theory are used. Finally, it is pointed out that although psychology is one of the social sciences traditionally involved in program evaluation, in the European context, psychologists seem to be almost absent from the evaluation of European programs. It is therefore suggested that European psychology and psychologists must make their presence more strongly felt in program evaluation.
Rheology and topography control the path of a lava flow: Insight from numerical simulations over a preexisting topography
Authors: Miyamoto Hideaki , Papp Kenneth R.
Published: August 2004

Determination of flow path is strongly controlled by both the preexisting topography and rheology of the lava flow. Using the Okmok 1997 eruption as an example lava flow, we perform numerical simulations of Bingham fluids flowing over preexisting topography and find that flow rheology determines whether or not new lobe formation (or bifurcation) occurs from the main flow at a topographic divide or remains confined by local topography. Therefore, lobe (or branch) length may increase for higher viscosity flows, when considering the effect of topographic control. Also, even one order of magnitude difference in the rheological properties allows lava flows to move in completely different paths, which may suggest that flow bifurcation due to topographic control provides insight to the local rheological properties of a lava flow. The effect reported here should be taken into account in risk assessments of future volcanic hazards.
Impact of snow cover and topography on ultraviolet irradiance at the Alpine station of Briançon
Authors: Lenoble Jacqueline , Kylling Arve , Smolskaia Irina
Published: August 2004

The enhancement of the UV global irradiance due to snow cover on the ground has been observed at the station of Briançon, in a high‐altitude Alpine valley. The analysis relies on a three‐dimensional (3‐D) model, using an elevation map of the area. Without snow, comparison with the results of a 1‐D model shows no detectable effect of topography, within the uncertainty of modeling (2–3%). The 3‐D model relates the enhancement due to snow to the altitude of the snow line. The enhancement is shown to depend on the snow distribution around the site and not on the topography itself. The enhancement was measured at Briançon for nine cloudless days in winter 2002. As expected, it increases with the decrease of the snow line. In erythemal UV the enhancement reaches a maximum of about 22% in the beginning of March, in agreement with the results of the 3‐D model, assuming a snow albedo of 0.3 above the snow line and below the tree line and 0.8 above the tree line. Retrieving an effective surface albedo is a very challenging problem. Very small uncertainties in enhancement (±2%) lead to large uncertainties (±0.05) in effective albedo. Using the snow distribution with a contribution function does not give good results when the snow line is high; this is explained by the low resolution of the map with the rapid variation of the contribution near the site.
Discourses of Objection: Towards an Understanding of Third-Party Rights in Planning
Authors: Ellis Geraint
Published: August 2004

Public participation is central to the practice, legitimacy, and dominant normative principles of spatial planning. It has a strong presence in the discourse of communicative governance, which suggests that participatory rights should be strengthened as part of a systematic institutional design. Interest in the concept of rights within planning has been gathering pace, but is still undeveloped. In terms of third-party rights, attention has been focused on citizens as rights claimants and their use of rights to promote self-interest, rather than the values that should be protected by such rights or the balance of rights between different stakeholders. This paper explores some of the theoretical issues related to third-party rights in planning, using the existing literature on planning disputes to contextualise current debate. It examines a case study of third-party appellants in the Republic of Ireland and identifies five distinct ‘discourses of objection’. These discourses highlight the complex factors that stimulate third-party rights-claims and illustrate how they can be related to issues such as citizenship, the public interest, and property rights. The paper concludes with a number of general observations on the nature of rights in planning and the implications this has for the broader paradigm of communicative governance.