bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sperm penetration into immature mouse oocytes and nuclear changes during maturation: an EM study
Authors: Szöllösi Daniel , Szöllösi Maria S. , Czolowska Renata , Tarkowski Andrzej K. 
Published: August 2004

Summary—The ultrastructure of oocyte and sperm nuclei was studied in mouse ovarian oocytes inseminated in vitro and cultured for 1 1/2 and 3 h in a medium containing dbcAMP or lacking the maturation inhibitor. In oocytes blocked at the germinal vesicle (GV) stage, certains maturation‐linked changes were noted. Sperm apposition and sperm‐oocyte fusion were similar to that during fertilization of ovulated oocytes. The sperm nucleus and its nuclear envelope remained intact after penetrating into the ovarian oocyte. One and a half h after removal of the drug (time 0 of maturation) the germinal vesicle (GV) and sperm nucleus remained intact. In oocytes maturing for 3 h, the nuclear envelopes of the GV and sperm nucleus had fragmented. The NE of the oocyte formed quadruple membranes while the NE of the sperm remained as flat vesicles. Oocyte chromatin condensed to form chromosomes, whereas at the same time the sperm chromatin was in the process of decondensation and was surrouded by fragments of the sperm NE. The sperm chromatin, composed of DNA complexed with protamines, consisted of thin fibrils; the individual fibrils measured 3.8 nm in diameter. Near the penetrated spermatozoa only occasional Mts were detected which were not related to the proximal centriole which was recognizable in the neck‐piece of the flagellum. Thus in mouse oocytes the introduced sperm centriole is not capable of behaving as a centrosome and organizing microtubules in the form of an aster.
Sodium butyrate inhibits c‐myc and stimulates c‐fos expression in all the steps of the cell‐cycle in hepatoma tissue cultured cells
Authors: Tichonicky Lydie , Kruh Jacques , Defer Nicole 
Published: August 2004

Summary—Soduim butyrate decreases the c‐myc mRNA and increases the c‐fos transcript level in HTC cells. This effect is independent of the cell‐cycle phase. Actinomycin D suppresses the effect on c‐fos. Cycloheximide increases both mRNA levels. Sodium butyrate suppresses the effect on c‐myc and potentializes the effect on c‐fos mRNAs. This suggests that sodium butyrate acts at the transcriptional level and that its effect does not result from the arrest of the cells at the G1 phase.
Ultrastructural patterns of the flagellar axoneme in the non‐motile part of the mole‐cricket sperm
Authors: Dallai Romano , Afzelius Björn A 
Published: August 2004

Summary—The mole‐cricket spermatozoon (Gryllotalpa gryllotalpa) has a motile anterior tail region and an immotile posterior region. The posterior portion appears stiff and its microtubular doublets and central singlet microtubules are swollen, apparently due to an excess of material within them. In particular, doublet number 6 is of an unusually large size. The general organization of the axoneme is also modified by a loss of dynein arms and spokes in the posterior portion. When studied by a fixation technique that involves tannic acid to outline the protein molecules and PA‐TCH‐Ag method for staining polysaccharides it could be seen that the microtubular doublets and accessory microtubules contain rounded globules surrounded by polysaccharides. The arrangement of protofilaments within the microtubular walls is visible both in the anterior tail region with normal doublets and in the posterior region with degenerated doublets.
A ground‐based model to study the effects of weightlessness on lymphocytes
Authors: Gmünder Felix K , Kiess Markus , Sonnefeld Gerry , Lee Juliet , Cogoli Augusto 
Published: August 2004

Summary—The mitogenic response of human lymphocytes was found to be markedly reduced in weightlessness conditions as compared to normal gravity. One possible explanation is that due to the non‐existent sedimentation in space the lymphocytes could not adhere and spread on a substratum. Thus, we investigated the effect of substratum adhesiveness on lymphocyte responsiveness by reducing and blocking cell adhesion with poly‐HEMA in a simple on‐ground system. Lymphocyte adhesiveness was assessed by measuring the proportion of non‐adhesive, slightly, and strongly adhesive 51Cr‐radiolabelled cells on uncoated and poly‐HEMA coated plastic. The amount of cell spreading on surfaces with varying adhesiveness was determined by measuring the area of cells. Cells grown on medium and thick poly‐HEMA films were rounded in shape. By contrast, on tissue culture plastic, they showed clear signs of spreading. The mitogenic response of lymphocytes grown on thick poly‐HEMA films was reduced by up to 68% of the control (tissue culture plastic). Interferon‐γ production was virtually nil when the cells were grown on the least adhesive substratum. These results show that activated lymphocytes need to anchor and spread prior to achieving an optimal proliferation response. We conclude that decreased lymphocyte adhesion could contribute to the depressed in vitro lymphocyte responsiveness found in the microgravity conditions of space flight.
Ultrastructure of E1 + 2 + 9 + 12 inversion breakpoints in Drosophila subobscura
Authors: Cuenca Juan Bautista , Saura Anja O , Sorsa Veikko , De Frutos Rosa 
Published: August 2004

Summary—The ultrastructure of the Drosophila subobscura chromosome regions around the breakpoints of the complex E1 + 2 + 9 + 12 gene arrangement was analyzed. This overlapping inversion is formed by the association of the E1, E2, E9, and E12 simple inversions. Ultrastructure of sections involving 58D/59A, 61C/D, 62D/63A, 64B/C, 67A/B, and 68B/C breakpoints on Est chromosomes were compared with the ultrastructure of sections involving 58D/68B, 62D/64C, 59A/63A, 64B/68C, 67B/61C, and 67A/61B breakpoints on E1 + 2 + 9 + 12 chromosomes. No detectable changes of structural organization on banding patterns induced by the E1 + 2 + 9 + 12 inversion were found. Ultrastructural analysis of the two E12 breakpoints has, however, facilitated the analysis of the left boundary of E12 inversion. Accordingly, we propose 61B/C as a new breakpoint instead of 61C/D.
Candida albicans— adriamycin interactions: ultrastructural and spectrofluorometric study of whole yeasts and spheroplasts
Authors: Bobichon Hélène , Bussy Véronique , Angiboust Jean‐François , Manfait Michel , Bouchet Philippe , Jardillier Jean‐Claude 
Published: August 2004

Summary—The occurrence of candidiasis in cancer patients who undergo chemotherapy requires the interrelation of Candida albicans and the antimitotic drug Adriamycin (ADM) which is well known as an intercalating agent. The whole yeasts were not affected by 2 h of contact with the drug at 10−4 M neither for their growth curve nor for their ultrastructure, despite the presence of free ADM on their surface. Spheroplasts displayed a delay in their growth and exhibited altered nucleoli with segregation of their granular and fibrillar components. The modified emission spectrum of ADM, determined by spectrofluorometry, corresponded neither to the free ADM nor to the DNA‐bound drug, but it could be related to a metabolite of the drug. The cell wall appeared to be one of the main sites for ADM resistance of Candida albicans in vitro.
Ferromagnetic isolation of endosomes: a novel method for subcellular fractionation of Xenopus oocytes
Authors: Bauer Alfred , Richter Hans‐Peter 
Published: August 2004

Summary—A novel method has been developed using ferric particles to label endosomes, and to achieve magnetic sorting of the various endocytic compartments involved in lipoprotein uptake into cells. Ferric particles conjugated to a receptor‐recognized ligand are bound to coated membrane pits and become internalized into the cytoplasm inside coated vesicles. After apparent fusion of the vesicles to tubular endosomes, the conjugates accumulate and finally discharge into multivesicular endosomes. Pulse‐chase experiments elucidate the pathway of internalized conjugates and allow both early compartments (pinosomes and tubular endosomes) and late compartments (multivesicular endosomes and storage organelles) to be selectively labelled. After ferroloading of the various transport compartments, the cells are homogenized and subcellularly fractionated. Sorting of labelled endosomes is performed by a specially designed “free‐flow” magnetic chamber.Prophase I‐arrested oocytes of the toad Xenopus laevis are used as a model system for studying the transport pathway and the conversion of the yolk precursor vitellogenin. It is possible to follow the route of internalization of vitellogenin‐iron conjugates via coated pits, coated vesicles, uncoated vesicles, tubular endosomes, multivesicular endosomes, and light primordial yolk platelets. These endosomes shuttle the ferric particles together with the vitellogenin from oolemma to preformed heavy yolk organelles which are still growing. In addition, these various compartments can be isolated according to their function and subjected to electron microscopy and to gel electrophoresis for detailed characterization of their limiting membranes as well as their contents.
Golgi complex and lysosomes in rabbit derived Pneumocystis carinii
Authors: Palluault François , Dei‐Cas Eduardo , Slomianny Christian , Soulez Benoît , Camus Daniel 
Published: August 2004

Summary—The ultrastructural morphology of Pneumocystis carinii obtained from nonimmunosuppressed rabbit is described in details. Golgi complex and primary lysosomes of P carinii are described here for the first time. They are easily revealed by the zinc iodide‐osmium tetroxide cytochemical reagent. Thiamine pyrophosphatase and β‐glycerophosphatase activities are found in the parasite but cytidine 5′ monophosphatase activity is not observed. A weak thiamine pyrophosphatase activity is detected in Golgi vesicles. An endomembranous saccular structure, present from the intracystic body stage to the precystic stage, apparently plays the role of secondary lysosome. A second type of endomembranous saccular structure, only present in the well developed trophozoitic and precystic forms is also described. The presence of carbohydrates in the cell wall of the parasite was demonstrated by periodic acid‐thiosemicarbazide‐silver proteinate staining and lectin concanavalin A labeling. The development of Golgi vesicles preceded the transition from double‐layered to three‐layered parasite stages.
Instability of pleomorphic tubulin paracrystals artificially induced by Vinca alkaloids in tissue‐cultured cells
Authors: Takanari Hideki , Yosida Toshimichi , Morita Joji , Izutsu Kosaku , Ito Tadahiro 
Published: August 2004

Summary—The processes of tubulin paracrystal induction in Chinese hamster ovary cells treated with a Vinca alkaloid, ie, vinblastine or vincristine, and treated simultaneously with one of the Vinca alkaloids and colcemid or colchicine were followed by four different microscopic techniques, in particular by tubulin‐immunofluorescence. Vinca alkaloid alone, in lower concentrations, induced basically tactoid or needle‐shaped (N‐shaped) paracrystals. However, the formation of crystalloid was greatly enhanced by increasing the concentration of Vinca alkaloid. Square or barrel‐shaped (S‐shaped) and hexagonal paracrystals were also commonly induced by simultaneous treatment with a Vinca alkaloid and colcemid or colchicine. Large rectangular paracrystals often displayed fibrillar or lamellar fine structures which ran perpendicular to the long axis but tended to cleave into fragments by spontaneous splitting. Electron micrographs revealed the fine structure of crystalloids to be aggregates of numerous filaments. The growth of paracrystals, particularly N‐shaped crystals, was markedly inhibited when cells were exposed to drug(s) at a low temperature (4°C). We confirmed that both N‐ and S‐shaped paracrystals dissociated rapidly after the culture medium was replaced with fresh, drug‐free medium. Glutaraldehyde‐fixed paracrystals treated with RNase solution were stained with acridine orange, showing a weak orange color. Possible factors involved in the assembly and disassembly of tubulin paracrystals are discussed.
Mapping the cellular distribution of labelled molecules by SIMS microscopy
Authors: Hindie Elif , Coulomb Bernard , Beaupain René , Galle Pierre 
Published: August 2004

Summary—We took advantage of one of the main possibilities of ion microscopy, ie isotopic analysis, to study the cellular distribution of molecules labelled either with carbon 14 or with stable isotopes of low natural abundance such as nitrogen 15 and deuterium. The surface of the sample is bombarded with an ion beam (O2+, Cs+ etc). Secondary ions emitted from the sample are filtered by a mass spectrometer and the distribution of the labelling isotope is recorded. In this way, we obtained images showing the characteristic distribution of 14C‐thymidine and d‐arginine in human fibroblasts, and of 15N‐adenine in organotypic cultures of human breast cancer cells. The spatial resolution on the acquired images was close to 0.1 μm when using the UPS‐ONERA ion microprobe. The sensitivity of the method for detecting carbon 14 is far greater than that of autoradiography and the technique is both fast and quantitative. On the other hand, the capacity of ion microscopy for studying the tissular distribution of molecules labelled with stable isotopes, opens the way for biological and pharmacological tracer studies of human diseases.
The imaging and quantification of aluminium in the human brain using dynamic secondary ion mass spectrometry (SIMS)
Authors: Candy John M. , Oakley Arthur E. , Mountfort Simon A. , Taylor Geoffrey A. , Morris Christopher M. , Bishop Hugh E. , Edwardson James A. 
Published: August 2004

Summary—Dynamic secondary ion mass spectrometry (SIMS) has been utilised to study the post‐mortem distribution of aluminium in air‐dried frozen sections from unfixed, unstained human brain in order to minimise contamination of the tissue and avoid redistribution and extraction of endogenous tissue aluminium. Substrates, sputter‐coated with silver, were found to be free of focal aluminium surface contamination and thus minimised substrate induced artefacts in the tissue aluminium ion image. SIMS imaging of aluminium secondary ions at a mass resolution that eliminated the major molecular interferences, combined with a photomontage technique provided a unique strategy for studying aluminium distribution in tissue unrivalled by other spatially resolved microanalytical techniques such as laser microprobe mass spectrometry or X‐ray microanalysis. Using this strategy, high densities of focal aluminium accumulations have been demonstrated in the cerebral cortex of the majority of chronic renal dialysis patients studied. In contrast, such aluminium accumulations were absent in control patients. SIMS imaging of aluminium appeared to provide much better discrimination between the dialysis patient group and the control group than one of the most widely used techniques for measuring aluminium in bulk samples, graphite furnace atomic absorption spectrometry. Preliminary studies have shown the feasibility of quantifying focal aluminium SIMS images obtained from brain tissue using aluminium‐loaded brain homogenates as reference standards.
The calcium loading of secretory granules. A possible key event in stimulus‐secretion coupling
Authors: Nicaise Ghislain , Maggio Katia , Thirion Sylvie , Horoyan Marianne , Keicher Erick 
Published: August 2004

Summary—The review focuses on calcium accumulation by secretory organelles. The observation that secretory granules contain variable and often important quantities of calcium (1–200 mM of total calcium) can be interpreted as a maturation index. A progressive loading with calcium would be permitted by a Ca2+‐transport mechanism on the granular membrane and calcium‐binding molecules in the granular core. The saturation of this store by the stimulus‐induced calcium transient would permit in mature (calciumloaded) granules the ionic crisis leading to exocytosis. The inside of secretory organelles being acidic, calcium influx into the granule can be driven by calcium‐proton exchange. The calcium‐proton exchanger could be a Ca2+‐ATPase.
Interaction of the Golgi membranes isolated from rabbit liver with microtubules in vitro
Authors: Murata Masayuki , Itoh Tomohiko J. , Kagiwada Satoshi , Hishida Ryuichi , Hotani Hirokazu , Ohnishi Shun‐Ichi 
Published: August 2004

Summary—We have developed a reconstituted model system to study the interaction of the Golgi membranes isolated from rabbit liver with taxol‐stabilized bovine‐brain microtubules without microtubule‐associated proteins (MAPs). The Golgi membranes are associated with microtubules. The sheets of vesicles and the membranous tubules are observed along microtubules by direct visualization using differential‐interference‐contrast, dark field, or fluorescence microscopy. The monoclonal antibody against Golgi membranes suggests that the Golgi membranes, but not the contaminating vesicles, are interacting with microtubules. The degree of association is assayed quantitatively using rhodamine‐labeled microtubules after separation of the complex from unbound microtubules by centrifugation upon sucrose gradient. The association is inhibited by crude MAPs, purified MAP2, or 1.0 mM ATP. However, the association neither requires the cytosol from rat liver or bovine brain nor N‐ethylmaleimide, brefeldin A, or GTP‐γ‐S. The association is mediated by trypsin‐sensitive peripheral protein(s) on the Golgi membranes.
Immunolabelling of the presynaptic membrane of Torpedo electric organ nerve terminals with an antiserum towards the acetylcholine releasing protein mediatophore
Authors: Brochier Guy , Israel Maurice , Lesbats Bernard 
Published: August 2004

Summary—Mediatophore is a nerve terminal membrane protein purified from Torpedo electric organ on its ability to translocate acetylcholine upon calcium action. An antiserum able to immunoprecipitate mediatophore activity was used to study the subcellular distribution of this protein. The presynaptic membrane exhibited a strong and discontinuous immunogold labelling, especially at the active zone where ACh is thought to be released. Two antigens were recognized on immunoblots of synaptosomal membranes: the 15‐kDa subunit of mediatophore and a 14‐kDa membrane protein that has a wide non‐neuronal distribution. Antibodies purified from the serum on native mediatophore and monospecific towards the 15‐kDa antigen still gave a high presynaptic membrane localized labelling. In addition, a few 14‐kDa protein sites were present at the active zone. The Schwann cell finger interposed between the presynaptic membrane and the postsynaptic arch also exhibited the 14‐kDa antigen raising the question of a possible interaction of mediatophore with the 14‐kDa protein originating from the Schwann cell.
Structural analysis of glycosyl‐phosphatidylinositol membrane anchor of the Toxoplasma gondii tachyzoite surface glycoprotein gp23
Authors: Tomavo Stanislas , Dubremetz Jean‐Francois , Schwarz Ralph T. 
Published: August 2004

Summary—In this study we describe the biochemical features of the Toxoplasma gondii tachyzoite surface glycoprotein, gp23, demonstrating that it is attached to the parasite membrane by a glycosyl‐phosphatidyl inositol anchor. Gp23 was metabolically labeled with tritiated palmitate, myristate, ethanolamine, inositol, glucosamine, mannose and galactose, as expected for a GPI‐anchor structure. Gp23 was released from the surface of living parasites after treatment with phosphatidyl inositol‐specific phospholipase C (PI‐PLC) and the resulting water‐soluble protein was immunoprecipitated with a monoclonal antibody specific for gp23. The GPIcore glycan was generated after aqueous‐HF dephosphorylation followed by nitrous acid deamination and its carbohydrate structure was analyzed using selective exo‐ and endoglycosidase treatments. Finally, the phosphatidylinositol moiety of gp23 was characterized using PI‐PLC and phospholipase A2 (PLA2) digestions. Our cumulative data suggest that gp23 of T gondii tachyzoites contains a modified GPI‐backbone similar to the mammalian Thy‐1 anchor, consisting of a conserved core structure (ethanolaminePO4‐6‐Manαl‐2‐Manαl‐6‐Manαl‐4‐GIcNαl‐6‐PI) bearing β‐linked N‐acetylgalactosamine residue(s).
Localization of a Band 3‐related protein in the mitochondria‐rich cells of amphibian skin epithelium
Authors: Devuyst Olivier , Rott Ruti , Denef Jean‐François , Crabbé Jean , Katz Uri 
Published: August 2004

Summary—Based on immunoblotting procedure, the isolated epithelium of amphibian skin was found to contain a 180 kDa protein which cross‐reacts with a polyclonal antiserum raised against human erythrocyte Band 3. Immunoperoxidase and immunofluorescence staining techniques indicated that the Band 3‐related protein was localized in the mitochondria‐rich cells (MRC) of this epithelium, with characteristic apical labelling pattern. Our findings show that the putative apical anion exchanger of the MRC is immunologically related to the band 3 multigenic family, which catalyzes Cl‐HCO3
− transmembranous exchange. It thus suggests a molecular basis for the role played by these cells in the transepithelial Cl pathway and acid‐base regulation.
Spherical functions on mixed symmetric spaces
Authors: Krötz Bernhard , Neeb Karl-Hermann , Ólafsson Gestur 
Published: August 2004

In this article we compute the spherical functions which are associated to hyperbolically ordered symmetric spacesH∖GH\backslash G. These spaces are usually not semisimple; one prominent example is given byH∖G=(Rn⋊Gl(n,R))∖(Hn⋊Sp(n,R))H\backslash G= ({\mathbb R}^n\rtimes {\mathrm {Gl}}(n,{\mathbb R}))\backslash (H_n\rtimes {\mathrm {Sp}} (n,{\mathbb R}))withHnH_nthe(2n+1)(2n+1)-dimensional Heisenberg group.
Expressing Evaluations
Authors: Davidson Donald 
Published: August 2004

Abstract
The author believes the attitude of the interpreter plays a crucial role in the theory of meaning. ‘Expressing Evaluation’ extends this strategy to evaluative judgements: just as the questions of belief and meaning are entwined, so are belief, meaning, and evaluation, where evaluating includes attitudes such as desires. This does not conflict with Davidson's claim that interpretation is a holistic act, in the sense that an interpreter weighs the attitudes of a subject against each other so as to render them intelligible or rational by the interpreter's standards. Justifies the thesis that desire is the most basic attitude in this interpretive process and that understanding presumes a shared body of evaluations as well as desires.
Problems in the Explanation of Action
Authors: Davidson Donald 
Published: August 2004

Abstract
Takes up a number of problems that arise by attempts to explain actions, and defends the author's causal theory of action. In particular, the author defends the claims that, first, if a person is killed by being shot, the shooting and the killing are one and the same event; secondly, a desire (or propositional pro‐attitude) is always involved in the causality and explanation of an action; and thirdly, though reason explanations of actions cannot be backed by strict laws, this does not imply that reasons, conceived of as conjunctions of beliefs and desires, are causally ineffectual.
A Unified Theory of Thought, Meaning, and Action
Authors: Davidson Donald 
Published: August 2004

Abstract
Spells out in more detail Davidson's Unified Theory of thought, meaning, and action the implications of which have been the focal point of the preceding chapters. The main task is to illuminate the conditions under which an understanding of the norms for our theories of intensional attribution is possible. What makes the task practicable at all, according to the author, is the structure the normative character of thought, desire, speech, and action imposes on correct attributions of attitudes to others, and hence on interpretations of their speech and explanations of their actions. Improving our understanding of the understanding of such norms requires improvement of the grasp of the standards of rationality implicit in all interpretation of thought and action.