White clover living mulch increases the yield of silage corn via arbuscular mycorrhizal fungus colonization

A field experiment was conducted to investigate the effects of white clover living mulch on the arbuscular mycorrhizal (AM) fungus colonization of corn roots and the yield of silage corn. The following seven treatments were setup in a field that had been kept bare by rotary tillage from August 2003 to July 2004: two white clover living mulch treatments without phosphorus (P) application, with the white clover shoots clipped and removed or allowed to lie in place before sowing corn; one no-tillage treatment without P application; and four rotary tillage treatments with different P application rates. White clover was broadcasted in the living mulch treatments in August 2004. In June 2005, the white clover shoots in the living mulch treatments were clipped. After tilling the four rotary tillage treatments, corn was sown in all the treatments. The fallow period before sowing corn was 0 month (living mulch treatments) and 22 months (no-tillage and rotary tillage treatments). At knee high stage, the AM fungus colonization of the corn roots and the P concentrations of the corn shoots in both the living mulch treatments were increased relative to those in the other treatments. The yield of corn tended to increase in the no-tillage and rotary tillage treatments with an increase in the P application rate. On the other hand, the yields of corn in the living mulch treatments without the P application were not significantly different from the maximum yield among the no-tillage and rotary tillage treatments. These results suggested that the white clover living mulch increased the yield of corn by facilitating the AM fungus colonization and improving the P nutrition of corn.     

Gene engineering of the adenovirus vector

The adenovirus vector is very attractive tool not only for the gene therapy but also for the basic sciences. However, because a construction method of this vector had been complex, only limited scientists had constructed and enjoyed the benefits. Recently, various methods were developed and the researchers came to be able to choose an efficient method, which is the COS-TPC method, or a concise procedure, which is the intact-genome transfection method (in vitro ligation method). Here we described not only these methods but also new method to construct the various Ads simultaneously using the recombinase-mediated cassette exchange (RMCE) by the site-specific recombinase. And also we want to refer the possibility to the worth of the vector, especially the vector of the expression-switch.     

The aryl hydrocarbon receptor is required for optimal resistance to Listeria monocytogenes infection in mice

The aryl hydrocarbon receptor (AhR) is part of a powerful signaling system that is triggered by xenobiotic agents such as polychlorinated hydrocarbons and polycyclic aromatic hydrocarbons. Although activation of the AhR by 2,3,7,8-tetrachlorodibenzo-p-dioxin or certain polycyclic aromatic hydrocarbons can lead to immunosuppression, there is also increasing evidence that the AhR regulates certain normal developmental processes. In this study, we asked whether the AhR plays a role in host resistance using murine listeriosis as an experimental system. Our data clearly demonstrate that AhR null C57BL/6J mice (AhR(-/-)) are more susceptible to listeriosis than AhR heterozygous (AhR(+/-)) littermates when inoculated i.v. with log-phase Listeria monocytogenes. AhR(-/-) mice exhibited greater numbers of CFU of L. monocytogenes in the spleen and liver, and greater histopathological changes in the liver than AhR(+/-) mice. Serum levels of IL-6, MCP-1, IFN-gamma, and TNF-alpha were comparable between L. monocytogenes-infected AhR(-/-) and AhR(+/-) mice. Increased levels of IL-12 and IL-10 were observed in L. monocytogenes-infected AhR(-/-) mice. No significant difference was found between AhR(+/-) and AhR(-/-) macrophages ex vivo with regard to their ability to ingest and inhibit intracellular growth of L. monocytogenes. Intracellular cytokine staining of CD4(+) and CD8(+) splenocytes for IFN-gamma and TNF-alpha revealed comparable T cell-mediated responses in AhR(-/-) and AhR(+/-) mice. Previously infected AhR(-/-) and AhR(+/-) mice both exhibited enhanced resistance to reinfection with L. monocytogenes. These data provide the first evidence that AhR is required for optimal resistance but is not essential for adaptive immune response to L. monocytogenes infection.     

Candida kazuoi sp. nov. and Candida hasegawae sp. nov., two new species of ascomycetous anamorphic yeasts isolated from insect frass in Thailand

Two strains of anamorphic yeasts isolated from insect frass collected in southern Thailand were assigned to the genus Candida based on the conventional taxonomic criteria used for yeast classification. In the phylogenetic tree based on the D1/D2 domain of the 26S rDNA, these strains are distant from the known species of yeasts and considered to represent two different new species. They are named Candida kazuoi sp. nov. and Candida hasegawae sp. nov.     

Novel peroxisomal protease Tysnd1 processes PTS1- and PTS2-containing enzymes involved in beta-oxidation of fatty acids

Peroxisomes play an important role in beta-oxidation of fatty acids. All peroxisomal matrix proteins are synthesized in the cytosol and post-translationally sorted to the organelle. Two distinct peroxisomal signal targeting sequences (PTSs), the C-terminal PTS1 and the N-terminal PTS2, have been defined. Import of precursor PTS2 proteins into the peroxisomes is accompanied by a proteolytic removal of the N-terminal targeting sequence. Although the PTS1 signal is preserved upon translocation, many PTS1 proteins undergo a highly selective and limited cleavage. Here, we demonstrate that Tysnd1, a previously uncharacterized protein, is responsible both for the removal of the leader peptide from PTS2 proteins and for the specific processing of PTS1 proteins. All of the identified Tysnd1 substrates catalyze peroxisomal beta-oxidation. Tysnd1 itself undergoes processing through the removal of the presumably inhibitory N-terminal fragment. Tysnd1 expression is induced by the proliferator-activated receptor alpha agonist bezafibrate, along with the increase in its substrates. A model is proposed where the Tysnd1-mediated processing of the peroxisomal enzymes promotes their assembly into a supramolecular complex to enhance the rate of beta-oxidation.     

Phosphorylation-induced conformational switching of CPI-17 produces a potent myosin phosphatase inhibitor

Phosphorylation of endogenous inhibitor proteins for type-1 Ser/Thr phosphatase (PP1) provides a mechanism for reciprocal coordination of kinase and phosphatase activities. A myosin phosphatase inhibitor protein CPI-17 is phosphorylated at Thr38 through G-protein-mediated signals, resulting in a >1000-fold increase in inhibitory potency. We show here the solution NMR structure of phospho-T38-CPI-17 with rmsd of 0.36 +/- 0.06 A for the backbone secondary structure, which reveals how phosphorylation triggers a conformational change and exposes an inhibitory surface. This active conformation is stabilized by the formation of a hydrophobic core of intercalated side chains, which is not formed in a phospho-mimetic D38 form of CPI-17. Thus, the profound increase in potency of CPI-17 arises from phosphorylation, conformational change, and hydrophobic stabilization of a rigid structure that poses the phosphorylated residue on the protein surface and restricts its hydrolysis by myosin phosphatase. Our results provide structural insights into transduction of kinase signals by PP1 inhibitor proteins.     

Amphiphysin 1 is important for actin polymerization during phagocytosis

Amphiphysin 1 is involved in clathrin-mediated endocytosis. In this study, we demonstrate that amphiphysin 1 is essential for cellular phagocytosis and that it is critical for actin polymerization. Phagocytosis in Sertoli cells was induced by stimulating phosphatidylserine receptors. This stimulation led to the formation of actin-rich structures, including ruffles, phagocytic cups, and phagosomes, all of which showed an accumulation of amphiphysin 1. Knocking out amphiphysin 1 by RNA interference in the cells resulted in the reduction of ruffle formation, actin polymerization, and phagocytosis. Phagocytosis was also drastically decreased in amph 1 (-/-) Sertoli cells. In addition, phosphatidylinositol-4,5-bisphosphate-induced actin polymerization was decreased in the knockout testis cytosol. The addition of recombinant amphiphysin 1 to the cytosol restored the polymerization process. Ruffle formation in small interfering RNA-treated cells was recovered by the expression of constitutively active Rac1, suggesting that amphiphysin 1 functions upstream of the protein. These findings support that amphiphysin 1 is important in the regulation of actin dynamics and that it is required for phagocytosis.     

Direct comparison of the pharmacodynamics of four antifungal drugs in a mouse model of disseminated candidiasis using microbiological assays of serum drug concentrations

The aim of this study was to compare the pharmacodynamics of the azole antifungal drugs fluconazole, itraconazole and ketoconazole, and the polyene antifungal amphotericin B, in a mouse model of disseminated Candida albicans infection. In order to directly compare effective serum concentrations of these antifungals, drug concentrations were assayed microbiologically by measuring inhibition of C. albicans mycelial growth (mMIC) in a mouse serum-based assay (serum antifungal titer). Efficacy in the mouse infection model was determined using an organ-based (kidney burden) endpoint. For all four drugs, the serum antifungal titers, 8 hr after administration of single doses of drugs at a range of drug concentrations, correlated closely with C. albicans kidney fungal burden in the mouse model. The results showed that determining serum antifungal titer may be used to accurately represent kidney fungal burden in a mouse model of disseminated candidiasis and allowed direct comparison of the pharmacodynamics of differing classes of antifungal drugs.