Proteomics Analysis of Plasma Membrane Fractions of the Root, Leaf, and Flower of Rice.

The plasma membrane regulates biological processes such as ion transport, signal transduction, endocytosis, and cell differentiation/proliferation. To understand the functional characteristics and organ specificity of plasma membranes, plasma membrane protein fractions from rice root, etiolated leaf, green leaf, developing leaf sheath, and flower were analyzed by proteomics. Among the proteins identified, 511 were commonly accumulated in the five organs, whereas 270, 132, 359, 146, and 149 proteins were specifically accumulated in the root, etiolated leaf, green leaf, developing leaf sheath, and developing flower, respectively. The principle component analysis revealed that the functions of the plasma membrane in the root was different from those of green and etiolated leaves and that the plasma membrane protein composition of the leaf sheath was similar to that of the flower, but not that of the green leaf. Functional classification revealed that the root plasma membrane has more transport-related proteins than the leaf plasma membrane. Furthermore, the leaf sheath and flower plasma membranes were found to be richer in proteins involved in signaling and cell function than the green leaf plasma membrane. To validate the proteomics data, immunoblot analysis was carried out, focusing on four heterotrimeric G protein subunits, Gα, Gß, Gγ1, and Gγ2. All subunits could be detected by both methods and, in particular, Gγ1 and Gγ2 required concentration by immunoprecipitation for mass spectrometry detection.

Identification of Heterotrimeric G Protein γ3 Subunit in Rice Plasma Membrane.

Heterotrimeric G proteins are important molecules for regulating plant architecture and transmitting external signals to intracellular target proteins in higher plants and mammals. The rice genome contains one canonical α subunit gene (RGA1), four extra-large GTP-binding protein genes (XLGs), one canonical ß subunit gene (RGB1), and five γ subunit genes (tentatively named RGG1, RGG2, RGG3/GS3/Mi/OsGGC1, RGG4/DEP1/DN1/OsGGC3, and RGG5/OsGGC2). RGG1 encodes the canonical γ subunit; RGG2 encodes the plant-specific type of γ subunit with additional amino acid residues at the N-terminus; and the remaining three γ subunit genes encode the atypical γ subunits with cysteine abundance at the C-terminus. We aimed to identify the RGG3/GS3/Mi/OsGGC1 gene product, Gγ3, in rice tissues using the anti-Gγ3 domain antibody. We also analyzed the truncated protein, Gγ3∆Cys, in the RGG3/GS3/Mi/OsGGC1 mutant, Mi, using the anti-Gγ3 domain antibody. Based on nano-liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, the immunoprecipitated Gγ3 candidates were confirmed to be Gγ3. Similar to α (Gα) and ß subunits (Gß), Gγ3 was enriched in the plasma membrane fraction, and accumulated in the flower tissues. As RGG3/GS3/Mi/OsGGC1 mutants show the characteristic phenotype in flowers and consequently in seeds, the tissues that accumulated Gγ3 corresponded to the abnormal tissues observed in RGG3/GS3/Mi/OsGGC1 mutants.

Characterization of Heterotrimeric G Protein γ4 Subunit in Rice.

Heterotrimeric G proteins are the molecule switch that transmits information from external signals to intracellular target proteins in mammals and yeast cells. In higher plants, heterotrimeric G proteins regulate plant architecture. Rice harbors one canonical α subunit gene (RGA1), four extra-large GTP-binding protein genes (XLGs), one canonical ß-subunit gene (RGB1), and five γ-subunit genes (tentatively designated RGG1, RGG2, RGG3/GS3/Mi/OsGGC1, RGG4/DEP1/DN1/qPE9-1/OsGGC3, and RGG5/OsGGC2) as components of the heterotrimeric G protein complex. Among the five γ-subunit genes, RGG1 encodes the canonical γ-subunit, RGG2 encodes a plant-specific type of γ-subunit with additional amino acid residues at the N-terminus, and the remaining three γ-subunit genes encode atypical γ-subunits with cysteine-rich C-termini. We characterized the RGG4/DEP1/DN1/qPE9-1/OsGGC3 gene product Gγ4 in the wild type (WT) and truncated protein Gγ4∆Cys in the RGG4/DEP1/DN1/qPE9-1/OsGGC3 mutant, Dn1-1, as littele information regarding the native Gγ4 and Gγ4∆Cys proteins is currently available. Based on liquid chromatography-tandem mass spectrometry analysis, immunoprecipitated Gγ4 candidates were confirmed as actual Gγ4. Similar to α-(Gα) and ß-subunits (Gß), Gγ4 was enriched in the plasma membrane fraction and accumulated in the developing leaf sheath. As RGG4/DEP1/DN1/qPE9-1/OsGGC3 mutants exhibited dwarfism, tissues that accumulated Gγ4 corresponded to the abnormal tissues observed in RGG4/DEP1/DN1/qPE9-1/OsGGC3 mutants.

Improvement of acne vulgaris by topical fullerene application: unique impact on skin care.

Oxidative stress plays a major role in acne formation, suggesting that oxygen radical scavengers are potential therapeutic agents. Fullerene is a spherical carbon molecule with strong radical sponge activity; therefore, we studied the effectiveness of fullerene gel in treating acne vulgaris. We performed an open trial using a fullerene gel twice a day; at 4 and 8 weeks, the mean number of inflammatory lesions (erythematous papules and pustules) significantly (P < 0.05) decreased from 16.09 ± 9.08 to 12.36 ± 7.03 (reduction rate 23.2%) and 10.0 ± 5.62 (reduction rate 37.8%), respectively. The number of pustules, consisting of accumulation of neutrophils, was significantly (P < 0.05) decreased from 1.45 ± 1.13 to 0.18 ± 0.60 (reduction rate 87.6%), and further in vitro assays of sebum production in hamster sebocytes revealed that 75 µM polyvinylpyrrolidone-fullerene inhibits sebum production, suggesting that fullerene suppresses acne through decreasing neutrophil infiltration and sebum production. After treatment for 8 weeks, the water content of the skin significantly (P < 0.05) increased from 51.7 ± 7.9 to 60.4 ± 10.3 instrumental units. Therefore, the fullerene gel may help in controlling acne vulgaris with skin care benefit. FROM THE CLINICAL EDITOR: Fullerenes, spherical carbon cages with strong oxygen radical scavenging, with formulated into a gel and used to successfully treat acne vulgaris, an inflammatory disease associated oxidative stress.

Cilostazol prevents amyloid ß peptide(25-35)-induced memory impairment and oxidative stress in mice.

BACKGROUND AND PURPOSE: Cilostazol may be effective in dementia associated with a cerebral ischaemia. In this study, we examined whether it exerts beneficial effects on learning and/or memory impairment induced by Aß(25-35) in mice, and compared its effects with those of aspirin. EXPERIMENTAL APPROACH: Aß(25-35) (9 nmol) was administered to mice i.c.v. Learning and memory behaviour were evaluated by measuring spontaneous alternation in a Y-maze and a step-down type passive avoidance test, on the 5th and 8th days after injection respectively. Levels of lipid peroxidation (malondialdehyde) and cytokines in the frontal cortex and hippocampus were measured 2, 3, 5 and 7 days after the Aß(25-35) injection. The effects of repeated administration of cilostazol and aspirin (both at 30 and 100 mg·kg(-1), p.o.) on any changes induced by Aß(25-35) were evaluated. KEY RESULTS: Repeated administration of cilostazol significantly attenuated the impairment of spontaneous alternation and the shortened step-down latency induced by Aß(25-35) . Aspirin did not show any beneficial effect. A significant increase in the levels of malondialdehyde (MDA) and IL-1ß (only measured in hippocampus) was observed 2, 3 and 5 days after the Aß(25-35) injection in the frontal cortex and hippocampus. Repeated administration of cilostazol (100 mg·kg(-1)) completely prevented the increase in MDA levels but failed to antagonize the increase in the expression of IL-1ß induced by Aß(25-35). CONCLUSIONS AND IMPLICATIONS: These results suggest that the protective effect of cilostazol on Aß(25-35)-induced memory impairment may be related to oxidative stress in the frontal cortex and the hippocampus.