S-(2-(acylamino)phenyl) 2,2-dimethylpropanethioates as CETP inhibitors

Studies on the relationship between the structure of the benzene moiety of S-(2-(acylamino)phenyl) 2,2-dimethylpropanethioates and CETP inhibitory activity were performed. Substituents on the benzene moiety influenced CETP inhibitory activity in a type and position dependent manner, and electron-withdrawing groups at the 4- or 5-position increased the activity. The most potent compound showed 50% inhibition of CETP activity in human plasma at a concentration of 2 microM.     

Cloning, Functional Characterization, and Mode of Action of a Novel Insecticidal Pore-Forming Toxin, Sphaericolysin, Produced by Bacillus sphaericus

An insecticidal protein produced by Bacillus sphaericus A3-2 was purified to elucidate its structure and mode of action. The active principle purified from the culture broth of A3-2 was a protein with a molecular mass of 53 kDa that rapidly intoxicated German cockroaches (Blattela germanica) at a dose of about 100 ng when injected. The insecticidal protein sphaericolysin possessed the undecapeptide motif of cholesterol-dependent cytolysins and had a unique N-terminal sequence. The recombinant protein expressed in Escherichia coli was equally as potent as the native protein. Sphaericolysin-induced hemolysis resulted from the protein's pore-forming action. This activity as well as the insecticidal activity was markedly reduced by a Y159A mutation. Also, coapplication of sphaericolysin with cholesterol abolished the insecticidal action, suggesting that cholesterol binding plays an important role in insecticidal activity. Sphaericolysin-lysed neurons dissociated from the thoracic ganglia of the German cockroaches. In addition, sphaericolysin's activity in ganglia was suppressed by the Y159A mutation. The sphaericolysin-induced damage to the cockroach ganglia was greater than the damage to the ganglia of common cutworms (Spodoptera litura), which accounts, at least in part, for the higher sensitivity to sphaericolysin displayed by the cockroaches than that displayed by cutworms.     

Coordinated Regulation of the Genes Participating in Starch Biosynthesis by the Rice Floury-2 Locus

The recessive floury-2 (flo-2) locus of rice (Oryza sativa L.), which is located on chromosome 4, causes a strong reduction in expression of the gene encoding an isoform of branching enzyme RBE1 in immature seeds 10 d after flowering. Mapping of the RBE1 gene demonstrated the localization on rice chromosome 6, suggesting that the wild-type Floury-2 (Flo-2) gene regulates RBE1 gene expression in trans. However, reduced expression of the genes encoding some other starch-synthesizing enzymes, including another isoform of branching enzyme RBE3 and granule-bound starch synthase, was also found in the flo-2 seeds. In spite of the low level of RBE1 gene expression in the immature seeds of the flo-2 mutants, the RBE1 gene was equally expressed in the leaves of the wild type and flo-2 mutants. Thus, these results imply that the Flo-2 gene may co-regulate expression of some of the genes participating in starch synthesis possibly in a developing seed-specific manner.     

Function of Arabidopsis SWAP70 GEF in immune response

In animals, major classes of Rho guanine nucleotide exchange factors (GEFs) possess a Dbl (diffuse B-cell lymphoma)- homology (DH) domain that functions as a GEF-catalytic domain. However, no GEFs with the DH domain had been identified in plants. Recently, we found that the rice homolog of human SWAP70, Oryza sative (Os) SWAP70, containing the DH domain, exhibited GEF activity toward the rice Rho GTPase OsRac1, and regulates chitin-induced production of reactive oxygen species and defense gene expression in rice.¹ Arabidopsis contains a single SWAP70 gene. A T-DNA insertion mutant of Arabidopsis SWAP70 was morphologically wild type. Measurement of in planta growth of Pseudomonas syringae DC3000 hrcC, a mutant incapable of type III effector delivery, revealed enhanced growth of the pathogen in the atswap70 mutant, indicating that AtSWAP70 is required for PAMP-triggered immunity. In addition, the atswap70 mutation reduced the RPM1-mediated hypersensitive response. These results suggested that AtSWAP70 plays a role in both PAMP- and effector-triggered immunity in Arabidopsis.     

Phosphorus deficiency-induced root elongation and its QTL in rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

A significant level of root elongation was induced in rice (Oryza sativa) grown under phosphorus-deficient conditions. The root elongation clearly varied among a total of 62 varieties screened under two different phosphorus levels. Two contrasting varieties, Gimbozu, with a low elongating response and Kasalath, with a high elongating response, were chosen and crossed to produce a hybrid population for QTL analyses. QTLs for the phosphorus deficiency-induced root elongation were detected by two linkage maps, i.e., one with 82 F₃ families constructed by 97 simple sequence repeat (SSR) and sequence-tag site markers and another with 97 F₈ lines by 790 amplified fragment length polymorphism and SSR markers. A single QTL for the elongation response was detected on chromosome 6, with a LOD score of 4.5 in both maps and explained about 20% of total phenotypic variance. In addition, this QTL itself, or a region tightly linked with it, partly explained an ability to reduce accumulation of excess iron in the shoots. The identified QTL will be useful to improve rice varieties against a complex nutritional disorder caused by phosphorus deficiency and iron toxicity.Electronic Supplementary Material Supplementary material is available for this article at     

Rice blast resistance gene Pikahei-1(t), a member of a resistance gene cluster on chromosome 4, encodes a nucleotide-binding site and leucine-rich repeat protein

Pikahei-1(t) is the strongest quantitative trait locus (QTL) for blast resistance in upland rice cv. Kahei, which has strong field resistance to the rice blast disease. A high-quality bacterial artificial chromosome library was used to fine-map Pikahei-1(t) within ~300 kb on the 31-Mb region on rice chromosome 4. Of the 42 predicted open reading frames, seven resistance gene analogs (RGAs) with the nucleotide-binding site and leucine-rich repeat (NBS-LRR) domain were identified. Among these, RGA1, 2, 3, 5, and 7, but not RGA4 and 6, were found to be expressed in Kahei and monogenic lines containing Pikahei-1(t). Blast inoculation of transgenic rice lines carrying the genomic fragment of each RGA revealed that only RGA3 was associated with blast resistance. On the basis of these results, we concluded that RGA3 is the Pikahei-1(t) and named it Pi63. Pi63 encoded a typical coiled-coil-NBS-LRR protein and showed isolate-specificity. These results suggest that Pi63 behaves like a typical Resistance (R) gene, and the strong and broad-spectrum resistance of Kahei is dependent on natural pyramiding of multiple QTLs. The blast resistance levels of Pi63 were closely correlated with its gene expression levels, indicating a dose-dependent response of Pi63 function in rice resistance. Pi63 is the first cloned R gene in the R gene cluster on rice chromosome 4, and its cloning might facilitate genomic dissection of this cluster region.     

Proliferation and tube formation of periodontal endothelial cells

Angiogenesis is indispensable to guide a regeneration of good periodontal tissue in the wound healing after periodontal surgery. Hepatocyte growth factor is well known for a strong angiogenic factor and it may play important roles in the periodontal tissue during periodontal wound healing. In exploring the promotion of angiogenesis in the periodontal ligament, proliferative and tubulogenic responses of endothelial cells to hepatocyte growth factor and to soluble factors secreted by fibroblasts were investigated. Pavement-shaped cells isolated from a human periodontal ligament were identified as the endothelial cell by their granular immunoreactivity for factor VIII. The proliferation of the endothelial cells was accelerated by the addition of hepatocyte growth factor or fibroblast-conditioned medium, and far more by adding both than either. The endothelial cells seeded on the agar containing both hepatocyte growth factor and fibroblast products formed a dense network in a shorter time than on the agar containing either. The endothelial cells in the dense network took a tube-like structure with lumen and were covered with laminin. These results suggest that hepatocyte growth factor administered into the regenerating periodontal tissue may promote, synergistically with local factors produced by the activated fibroblast, the proliferation and tubulogenesis of the remaining endothelial cells.