Fight to the death: Arabidopsis thaliana defense response to fungal necrotrophic pathogens

Necrotrophic fungi, being the largest class of fungal plant pathogens, pose a serious economic problem to crop production. They are the cause of heavy losses in agriculture worldwide. Understanding the process of plant infection by necrotrophic fungi, including subtle interaction networks connecting such evolutionarily distinct organisms has recently been given high research priority. Such studies are now possible mainly because of the utility of the model plant Arabidopsis thaliana. A. thaliana has a sequenced genome and thousands of mutants available, allowing investigation of virtually all aspects of plant pathogenesis. This review focuses on morphological and molecular changes in A. thaliana, which occur during response to infection by necrotrophic fungi. These responses in relation to resistance and susceptibility of the plant will be discussed.     

Synthesis of N-Acetylglucosamine Aryl β-Glycosides Catalyzed by Crown Compounds

Glycosylation of various phenols with -D-glucosaminyl chloride peracetate in a solid phase–liquid system catalyzed by crown compounds was studied. The highest yields of aryl -glycosides were observed at room temperature in acetonitrile using anhydrous potassium carbonate as a base. The optimum phenol–glycosyl donor–base–crown ether ratio was 1 : 1 : 1 : 0.2.     

Use of cocultured cell systems to elucidate chemokine-dependent neuronal/microglial interactions: control of microglial activation

In order to understand processes involved in central nervous system inflammatory diseases, a critical appreciation of mechanisms involved in the control of immune function in the brain is needed. Microglial cells are watchful eyes for unusual events and detecting the presence of pathogens but are also alert to signals emanating from damaged neurons. Fractalkine (CX3CL1) is a chemokine which is expressed predominantly in the central nervous system, being localized on neurons, while its receptor, CX3CR1, is found on microglial cells. We have developed a strategy to investigate the role of this chemokine in neuronal-microglia interactions. Because fractalkine is expressed both as a soluble and as a membrane-attached protein, we have established various protocols involving different levels of cell-to-cell communication. Three experimental systems were instituted, including (1) a conditioned medium transfer system in which no cell-cell communication or contact is possible, (2) a transwell system that permits cell-contact-independent communication through diffusible soluble factors only, and (3) a coculture system allowing cell-to-cell communication via direct microglial-neuronal contacts. Using these in vitro cocultured systems, we have investigated the role of a soluble and/or cell-associated chemokine, such as fractalkine, in order to obtain insights into the role of glia-neuron interactions in cerebral inflammation.     

Revision of the Genus Scopelogadus (Melamphaidae). 4. S. multilamellatus sp. n. and S. unispinis

Journal of Ichthyology - A new species Scopelogadus multilamellatus sp. n. has been described from the tropical waters of the Indian Ocean. The new species has a large number of pseudobranchial...     

Revision of the genus <Emphasis Type="Italic">Melamphaes</Emphasis> (Melamphaidae). 5. Oligo-raker species: <Emphasis Type="Italic">M. indicus</Emphasis>, <Emphasis Type="Italic">M. eurous</Emphasis>, and <Emphasis Type="Italic">M. typhlops</Emphasis>

Three oligo-raker species (?19 rakers on the first gill arch) of the genus Melamphaes out of the “M. typhlops” group are considered. The validity of M. indicus Ebeling is restored. This species inhabits equatorial and tropical waters of the Indian Ocean and the western part of the Pacific Ocean. M. eurous sp. n., which is related to M. indicus, is described from equatorial waters of the eastern part of the Pacific Ocean. M. typhlops (Lowe) inhabiting the northern part of the Atlantic Ocean, from the equatorial zone about to 45° N, is redescribed.     

A Mutation in the Mitochondrial Fission Gene Dnm1l Leads to Cardiomyopathy

Mutations in a number of genes have been linked to inherited dilated cardiomyopathy (DCM). However, such mutations account for only a small proportion of the clinical cases emphasising the need for alternative discovery approaches to uncovering novel pathogenic mutations in hitherto unidentified pathways. Accordingly, as part of a large-scale N-ethyl-N-nitrosourea mutagenesis screen, we identified a mouse mutant, Python, which develops DCM. We demonstrate that the Python phenotype is attributable to a dominant fully penetrant mutation in the dynamin-1-like (Dnm1l) gene, which has been shown to be critical for mitochondrial fission. The C452F mutation is in a highly conserved region of the M domain of Dnm1l that alters protein interactions in a yeast two-hybrid system, suggesting that the mutation might alter intramolecular interactions within the Dnm1l monomer. Heterozygous Python fibroblasts exhibit abnormal mitochondria and peroxisomes. Homozygosity for the mutation results in the death of embryos midway though gestation. Heterozygous Python hearts show reduced levels of mitochondria enzyme complexes and suffer from cardiac ATP depletion. The resulting energy deficiency may contribute to cardiomyopathy. This is the first demonstration that a defect in a gene involved in mitochondrial remodelling can result in cardiomyopathy, showing that the function of this gene is needed for the maintenance of normal cellular function in a relatively tissue-specific manner. This disease model attests to the importance of mitochondrial remodelling in the heart; similar defects might underlie human heart muscle disease.     

A sensitive and specific HPLC method for the determination of total pentosidine concentration in plasma

Pentosidine is an advanced glycation end-product (AGE) appearing when arginine and lysine residues in proteins are cross-linked with carbonyl derivatives. This paper presents an improved method for the synthesis of pentosidine and reversed-phase chromatography of this substance with fluorometric detection that enables sensitive (0.01 pmol/mg protein) and specific determination of pentosidine in plasma. Separation is done twice on the same C(18) Vydac 218TP54 column, first with trifluoroacetic acid and next with heptafluorobutyric acid as ion pair. The inter-day coefficient of variation is 6.4% at pentosidine concentration in plasma of 25 pmol/mg protein and 8% at 1.7 pmol/mg protein. Spectral properties of pentosidine exploited during identification of the substance with UV absorption and fluorescence detectors are described. Maximum of absorbance was observed at 325 nm, maximum fluorescence at lambda(ex)/lambda(em)=330/373 nm. The method may prove useful for the study of processes associated with generation and accumulation of pentosidine in the body as a marker of AGE production in healthy subjects and patients with chronic renal failure.     

Detection and analysis of tumor fluorescence using a two-photon optical fiber probe

The utility of a two-photon optical fiber fluorescence probe (TPOFF) for sensing and quantifying tumor fluorescent signals was tested in vivo. Xenograft tumors were developed in athymic mice using MCA207 cells expressing green fluorescent protein (GFP). The TPOFF probe was able to detect ex vivo fluorescence from excised tumors containing as little as 0.3% GFP-expressing cells. TPOFF results were similar to both flow-cytometric analysis of tumor cells after isolation and suspension, and fluorescence determined by microscope images of cryosectioned tumors. TPOFF was then used to measure GFP fluorescence from tumors in live mice. The fiber probe detected fluorescently-labeled Herceptin antibody targeted to HER2-expressing tumors in severe combined immunodeficient mice. Dendrimer nanoparticles targeted by folic acid and having 6-TAMRA as a fluorescent probe were also used to label KB cell tumors in vivo. The fiber probe documented a fourfold increase in tumor fluorescence in animals that received the targeted dendrimer. These results suggest TPOFF can be used as a minimally invasive system for identifying tumor markers and monitoring drug therapy.