Cephalostatin 1 is a bis-steroidal marine natural product with a unique cytotoxicity profile in the in vitro screen system of the National Cancer Institute, suggesting that it may affect novel molecular target(s). Here we show that cephalostatin 1 induces a novel pathway of receptor-independent apoptosis that selectively uses Smac/DIABLO (second mitochondria-derived activator of caspases/direct inhibitor of apoptosis-binding protein with a low isoelectric point) as a mitochondrial signaling molecule. At nanomolar concentrations, cephalostatin 1 triggers dose- and time-dependent DNA fragmentation in leukemia Jurkat T cells.
View Article and Find Full Text PDFA successful defense against potential pathogens requires that a host organism is able to discriminate between self and nonself structures. Soybean (Glycine max L.) exploits a specific molecular pattern, a 1,6-beta-linked and 1,3-beta-branched heptaglucoside (HG), present in cell walls of the oomycetal pathogen Phytophthora sojae, as a signal compound eliciting the onset of defense reactions.
View Article and Find Full Text PDFThe nuclear atpC1 gene encoding the gamma subunit of the plastid ATP synthase has been inactivated by T-DNA insertion mutagenesis in Arabidopsis thaliana. In the seedling-lethal dpa1 (deficiency of plastid ATP synthase 1) mutant, the absence of detectable amounts of the gamma subunit destabilizes the entire ATP synthase complex. The expression of a second gene copy, atpC2, is unaltered in dpa1 and is not sufficient to compensate for the lack of atpC1 expression.
View Article and Find Full Text PDFLangenbecks Arch Chir Suppl Kongressbd
November 2003
The effect of rG-CSF on wound healing in neutropenic mice was studied in the wound healing model on the ear of hairless mice. Animals were treated with a daily dose of rG-CSF (i.p.
View Article and Find Full Text PDFLangenbecks Arch Chir Suppl Kongressbd
November 2003
In endotoxin-exposed rat livers, G-CSF caused a reduction of CINC gene transcripts in the nonparenchymal cell fraction, which might be the mechanism for attenuation of microvascular leukocyte adherence and leukocyte-dependent tissue injury, as observed upon G-CSF application in a model of endotoxin-induced hepatotoxicity.
View Article and Find Full Text PDFHigh-resolution detection of phosphorylated histone H3 at serine 10 in mitotic barley chromosomes for scanning electron microscopy was shown using a novel application of indirect immunogold labeling with Nanogold. This method permits localization and quantification of signals in a three-dimensional context. Because the chromosome structure is well preserved, characterization of binding sites (chromomeres, parallel matrix fibers, solenoids), currently in the realm of nanometer decades, is possible.
View Article and Find Full Text PDFPasteurella multocida is an important animal pathogen. Bacterial ghosts produced by the expression of phage PhiX174 lysis gene E are empty cells devoid of cytoplasmic and genomic material. Lysis of P.
View Article and Find Full Text PDFThe lignin distribution in cell walls of spruce and beech wood was determined by high-voltage transmission-electron-microscopy (TEM) in sections stained with potassium permanganate as well as by field-emission-scanning-electron-microscopy (FE-SEM) combined with a back-scattered electron detector on mercurized specimens. The latter is a new technique based on the mercurization of lignin and the concomitant visualization of mercury by back-scattered electron microscopy (BSE). Due to this combination it was possible to obtain a visualized overview of the lignin distribution across the different layers of the cell wall.
View Article and Find Full Text PDFIn yeasts and mammals, PEX10 encodes an integral membrane protein with a C3HC4 RING finger motif in its C-terminal domain and is required for peroxisome biogenesis and matrix protein import. In humans, its dysfunction in peroxisome biogenesis leads to severe Zellweger Syndrome and infantile Refsum disease. Here we show that dysfunction of a homologous gene in Arabidopsis leads to lethality at the heart stage of embryogenesis, impairing the biogenesis of peroxisomes, lipid bodies, and protein bodies.
View Article and Find Full Text PDFPhotosystem (PSII) is a supramolecular polypeptide complex found in oxygenic photosynthetic membranes, which is capable of extracting electrons from water for the reduction of plastoquinone. An intriguing feature of this assembly is the fact that it includes more than a dozen low-mass polypeptides of generally unknown function. Using a transplastomic approach, we have individually disrupted the genes of the psbEFLJoperon in Nicotiana tabacum, which encode four such polypeptides, without impairing expression of downstream loci of the operon.
View Article and Find Full Text PDFBackground: Operative treatment of displaced proximal humeral fractures often results in poor functional outcome. We report a technique that provides improved rotational stability of the fracture and thus allows early functional treatment.
Methods: Seventy-one consecutive patients (67 +/- 18 years) with displaced fractures of the proximal humerus (two-part, n = 10; three-part, n = 41; four-part, n = 20) were treated by open reduction and internal fixation using two one-third tubular plates on the anterior and lateral aspects of the proximal humerus.
The esterification kinetics of chlorophyllide, obtained by a single flash of light, were investigated in etiolated barley ( Hordeum vulgare L.) and oat ( Avena sativa L.) leaves.
View Article and Find Full Text PDFUsing post-embedding immunogold techniques the cytological localization of the two branchpoint enzymes of isoquinoline biosynthesis, berberine bridge enzyme (BBE) and (S)-tetrahydroprotoberberine oxidase (STOX), was demonstrated. Electron-microscopic examination revealed their exclusive compartmentation within vesicles. After these vesicles have fused with the central vacuole, they release their contents, resulting in a characteristic electron-dense precipitate at the tonoplast.
View Article and Find Full Text PDFDuring its haploid phase the dimorphic fungus Ustilago maydis grows vegetatively by budding. We have identified two genes, don1 and don3, which control the separation of mother and daughter cells. Mutant cells form tree-like clusters in liquid culture and grow as ring-like (donut-shaped) colonies on solid medium.
View Article and Find Full Text PDFWe have identified mutations in six previously uncharacterized genes of Arabidopsis, named club, bublina, massue, rod, bloated, and bims, that are required for cytokinesis. The mutants are seedling lethal, have morphological abnormalities, and are characterized by cell wall stubs, gapped walls, and multinucleate cells. In these and other respects, the new mutants are phenotypically similar to knolle, keule, hinkel, and pleiade mutants.
View Article and Find Full Text PDFCutaneous chlorellosis in a gazelle caused a chronic granulomatous inflammation in the subcutaneous tissue of the carpus. The diagnosis was based on the intense green color of the lesion and the presence of organisms identified as algae of the order Chlorellales. According to morphologic and ultrastructural features, the genus Bracteacoccus is most likely.
View Article and Find Full Text PDFSummary Root cell wall proteins involved in the incompatible interaction between soybean (Glycine max L.) and the phytopathogenic oomycete Phytophthora sojae were investigated by a proteomic approach using ESI-MS/MS analysis. Success of infection and subsequently induced defence reactions was proven by staining the cell wall localized defence-related 1,3-beta-glucan, callose, in semi-thin sections of the roots.
View Article and Find Full Text PDFStrain EDIVT, an exopolysaccharide-producing bacterium, was subjected to polyphasic characterization. The bacterium produced copious amounts of an extracellular polysaccharide, forming slimy, viscous, intensely yellow-pigmented colonies on Czapek-Dox (CZD) agar. The culture fluids of the liquid version of CZD medium were highly viscous after cultivation for 5 d.
View Article and Find Full Text PDFWe report the identification of novel archaea living in close association with bacteria in the cold (approximately 10 degrees C) sulfurous marsh water of the Sippenauer Moor near Regensburg, Bavaria, Germany. These microorganisms form a characteristic, macroscopically visible structure, morphologically comparable to a string of pearls. Tiny, whitish globules (the pearls; diameter, about 0.
View Article and Find Full Text PDFWe present a new model of the three-dimensional structure of chromosomes. With DNA and protein staining it could be shown by high-resolution scanning electron microscopy that metaphase chromosomes are mainly composed of DNA packed in "chromomeres" (coiled solenoides) and a dynamic matrix formed of parallel protein fibers. In the centromeric region, the chromomeres are less densely packed, giving insight into the matrix fibers.
View Article and Find Full Text PDFThe opium poppy (Papaver somniferum) belongs to the group of latex-containing plants. Latex is the milky-like fluid within laticifer cells. In this study, poppy latex was analyzed with respect to ultrastructure, alkaloid, and protein content.
View Article and Find Full Text PDFMol Plant Microbe Interact
October 2000
In the corn smut fungus Ustilago maydis, mating of two haploid sporidia is a prerequisite for subsequent colonization of the host. Cyclic AMP (cAMP) and pheromone signals have been implicated in this developmental program. The cAMP pathway is also needed for subsequent fungal development in planta, as null mutants in any component of the pathway fail to form tumors.
View Article and Find Full Text PDFPathogenic development in the corn smut fungus Ustilago maydis is controlled by a heterodimer of the two homeodomain proteins bE and bW which are encoded by the b mating type locus. The bE/bW heterodimer is thought to achieve its function as a transcriptional regulator of pathogenicity genes, either directly by binding to cis regulatory sequences or indirectly via a b-dependent regulatory cascade. In a screen for components of the b-dependent regulatory cascade we have isolated Rum1 (regulator U.
View Article and Find Full Text PDFAfter selective enrichment and differential hybridisation of Cot-1 DNA fractions of plants with and without polymorphic heterochromatic segments, a repetitive sequence (called Bds1) specific to the polymorphic chromosome segments of Brachycome dichromosomatica (Brachyscome dichromosomatica) was isolated. A single repeat unit of Bds1 is 92 bp long and is organised in tandem arrays at three different polymorphic segment sites on the chromosomes of cytodeme A2. Although all three sites showed extensive polymorphism between plants, the karyotypes of all analysed mitotic root cells were stable within a single plant.
View Article and Find Full Text PDFThe minimal number of genes required for the formation of gas vesicles in halophilic archaea has been determined. Single genes of the 14 gvp genes present in the p-vac region on plasmid pHH1 of Halobacterium salinarum (p-gvpACNO and p-gvpDEFGHIJKLM) were deleted, and the remaining genes were tested for the formation of gas vesicles in Haloferax volcanii transformants. The deletion of six gvp genes (p-gvpCN, p-gvpDE, and p-gvpHI) still enabled the production of gas vesicles in H.
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