Porphyromonas gingivalis is a periodontitis-associated pathogen and interactions between the bacterium and gingival fibroblasts play an important role in development and progression of periodontitis, an inflammatory disease leading to degeneration of tooth-supporting structures. Gingival fibroblasts, which expresses protease activated receptors (PARs) as well as toll-like receptors (TLRs), produces inflammatory mediators upon bacterial challenges. In this study, we elucidated the importance of PAR1, PAR2, TLR2 and TLR4 for the expression and secretion of CXCL8, interleukin-6 (IL-6), transforming growth factor-β1 (TGF-β1) and secretory leukocyte inhibitor (SLPI). Human gingival fibroblasts were transfected with small-interfering RNA against the target genes, and then stimulated with P. gingivalis wild-type W50 and W50-derived double rgp mutant E8 and kgp mutant K1A. TLR2-silencing reduced P. gingivalis-induced CXCL8 and IL-6. IL-6 was also reduced after PAR1-silencing. No effects were observed for TGF-β1. SLPI was suppressed by P. gingivalis and silencing of PAR1 as well as TLR2, gave additional suppression at the mRNA level. TLR4 was not involved in the regulation of the investigated mediators. CXCL8 and IL-6 are important for progression and development of periodontitis, leading to a chronic inflammation that may contribute to the tissue destruction that follows an exacerbated host response. Therefore, regulating the expression of TLR2 and subsequent release of CXCL8 and IL-6 in periodontitis could attenuate the tissue destruction seen in periodontitis.

We found that appropriate treatment with a highly potent and long-lasting abscisic acid analog enhanced the tissue expansion of scutellum during early seedling development of rice, accompanied by increases of protein and starch accumulation in the tissue. A comparative display of the protein expression patterns in the abscisic acid analog-treated and non-treated tissues on two dimensional gel electrophoretogram indicated that approximately 30% of the scutellar proteins were induced by abscisic acid. The abscisic acid-induced proteins included sucrose metabolizing, glycolytic, and ATP-producing enzymes. Most of these enzyme proteins also increased during the seedling growth. In addition, the expression of some isoforms of UDP-glucose pyrophosphorylase, 3-phosphoglycerate kinase, and mitochondrial ATP synthase beta chain was stimulated in the scutellum, with suppressed expression of α-amylase. We concluded that abscisic acid directly and indirectly stimulates the expression of numerous proteins, including carbohydrate metabolic enzymes, in scutellar tissues.

The Golgi membranes labeled with cis-Golgi marker GFP-SYP31 were isolated from suspension-cultured cells of rice transformed with 35S::GFP-SYP31 by floating through a discontinuous sucrose density gradient in the presence of 5 mM MgCl2. The specific fluorescence intensity of final membrane preparation increased to approximately 150-fold in comparison with that of the post-nucleus soluble fraction. Specific activity of membrane-bound α-mannosidase (cis-Golgi) markedly increased, but NDPase (medial-/trans-Golgi) and NADPH-cytochrome c reductase endoplasmic reticulum were weakly detected in the membrane fraction. The other organelle marker enzymes, cytochrome c oxidase (mitochondria), alkaline pyrophosphatase (plastid), and catalase (peroxisome) were not detectable. Comparative display of protein spots in GFP-SYP31-labeled membranes, microsomal membranes and soluble fraction on the two dimensional gels showed that some proteins are markedably concentrated in the cis-Golgi membrane fraction. Furthermore, the mass spectrometric analysis of proteins separated by SDS-polyacrylamide gel electrophoresis indicated that the highly purified Golgi membranes contained several membrane traffic-related proteins and ER resident proteins. These findings indicated a close relationship between the ER and the cis-Golgi membranes.

α-Amylase isoforms I-1 and II-4 were found in rice grains during ripening, α-amylase II-4 being the most predominant isoform. To determine their functions in ripening seeds, we generated a series of transgenic rice plants transformed with α-amylase I-1 and α-amylase II-4 cDNA under the control of Cauliflower mosaic virus 35S promoter. These isoforms were increased in young shoot and mature leaf tissues of the transgenic plants at both mRNA and protein levels. The starch accumulation in leaves was reduced to 42-82% of that in the wild-type. The transgenic lines A3-1 and D1-4, which overexpressed α-amylase I-1 and α-amylase II-4, respectively, were examined further. The enzyme activity was increased in both seeds, and the increase was greater in D1-4. The dry weight of A3-1 and D1-4 seeds was decreased approximately 4 and 11%, respectively. White immature grains frequently appeared in both lines, with severer abnormalities seen in D1-4. These results strongly suggest that the increase of α-amylase activities inhibits the accumulation of reserve starch and lowers the grain quality of rice.