Immunochemical evidence for the light-regulated modulation of phosphatidylinositol-4,5-bisphosphate in rat photoreceptor cells

Immunocytochemical localization of phosphatidylinositol-4,5-bisphosphate (PIP2) in the rat rod photoreceptor outer segments (OS) was investigated with rabbit antiPIP2 antibodies. The OS of the light-adapted rat eye showed little or no staining, whereas the OS of the dark-adapted eye were intensely stained for PIP2. The immunoreactivity of photoreceptor PIP2 in the eye exposed to a brief flash of light was markedly reduced. However, subsequent dark-adaptation of the flash-bleached eye resulted in a rapid recovery of PIP2 immunoreactivity; dark-adaptation for 5 min was sufficient for recovery to the fully dark-adapted level. In dark-adapted eyes exposed to graded light intensities, the PIP2 immunostaining varied with light levels and was correlated with unbleached rhodopsin concentrations. These results suggest that PIP2 in the rat photoreceptor cells is rapidly hydrolyzed upon light exposure and rapidly synthesized in the dark and that the decrease of PIP2 level is triggered by photic bleaching of rhodopsin.     

Gymnospermin: A new labdan triol from Gymnosperma glutinosa

The structure of gymnospermin (1), a new diterpene triol isolated from a collection of Gymnosperma glutinosa (Compositae) from Mexico, has been determined to be (?)-7β,8α,15-trihydroxy-labdan.     

Mechanisms of contact photosensitivity in mice. IV. Antigen-specific suppressor T cells induced by preirradiation of photosensitizing site to UVB

Mice were successfully contact photosensitized with 3,3',4',5-tetrachlorosalicylanilide (TCSA) plus black light irradiation. Pre-exposure of the photosensitizing site (ca 5 cm2) to UVB (280 to 320 nm; 400 mJ/cm2) rendered mice unresponsive to a challenge reaction. Cell transfer experiments demonstrated that the spleens from the nonreactive mice contained suppressor T cells (Ts) that were antigen-specific and that blocked the afferent limb of contact photosensitivity to TCSA. To exert suppressive functions, Ts required another population of cyclophosphamide-sensitive T cells that resided in the spleens of nonsensitized mice. The results provide evidence that UVB-induced aberrant homeostasis of the skin caused a marked suppression of immune system that is associated with the generation of Ts.     

The Daiokanzoto (TJ-84) Kampo Formulation Reduces Virulence Factor Gene Expression in Porphyromonas gingivalis and Possesses Anti-Inflammatory and Anti-Protease Activities

Kampo formulations used in Japan to treat a wide variety of diseases and to promote health are composed of mixtures of crude extracts from the roots, bark, leaves, and rhizomes of a number of herbs. The present study was aimed at identifying the beneficial biological properties of Daiokanzoto (TJ-84), a Kampo formulation composed of crude extracts of Rhubarb rhizomes and Glycyrrhiza roots, with a view to using it as a potential treatment for periodontal disease. Daiokanzoto dose-dependently inhibited the expression of major Porphyromonas gingivalis virulence factors involved in host colonization and tissue destruction. More specifically, Daiokanzoto reduced the expression of the fimA, hagA, rgpA, and rgpB genes, as determined by quantitative real-time PCR. The U937-3xκB-LUC monocyte cell line transfected with a luciferase reporter gene was used to evaluate the anti-inflammatory properties of Daiokanzoto. Daiokanzoto attenuated the P. gingivalis-mediated activation of the NF-κB signaling pathway. It also reduced the secretion of pro-inflammatory cytokines (IL-6 and CXCL8) by lipopolysaccharide-stimulated oral epithelial cells and gingival fibroblasts. Lastly, Daiokanzoto, dose-dependently inhibited the catalytic activity of matrix metalloproteinases (-1 and -9). In conclusion, the present study provided evidence that Daiokanzoto shows potential for treating and/or preventing periodontal disease. The ability of this Kampo formulation to act on both bacterial pathogens and the host inflammatory response, the two etiological components of periodontal disease, is of high therapeutic interest.     

In vitro production of antibody to hepatitis B core and E antigens by peripheral blood mononuclear cells in patients with chronic hepatitis B virus infection

To evaluate the relative immunogenicity of and the mechanism for production of antibody to hepatitis B core (HBc) and hepatitis B e (HBe) Ag, we investigated the in vitro anti-HBc and anti-HBe production by PBMC from 25 patients with chronic active hepatitis (CAH) (15 with HBeAg and 10 with anti-HBe) and 12 ASC (5 with HBeAg and 7 with anti-HBe) in the presence of PWM, rHBcAg, or purified HBeAg. PWM-stimulated culture produced higher titer anti-HBc (mean % inhibition +/- SD = 73 +/- 23%, p less than 0.001) than anti-HBe (34 +/- 17%). HBcAg stimulation elicited greater anti-HBc response (43 +/- 26%, p less than 0.001) than did HBeAg for anti-HBe (26 +/- 12%). Both HBcAg and HBeAg induced equivalent anti-HBe response. Anti-HBc production in response to HBcAg was higher in CAH patients (51 to 55%) than in asymptomatic carriers of hepatitis B surface Ag (22 to 28%) irrespective of their HBeAg/anti-HBe status, but reflecting serum anti-HBc value. Similar findings were noted in HBeAg-stimulated anti-HBe production for the two patient groups. In HBeAg- and anti-HBe-positive CAH, HBcAG-stimulated anti-HBc production was similar in T (1.4 x 10(6)) and B (0.6 x 10(6)) cells coculture, and B cells (2 x 10(6)) alone culture. However, in the HBeAg-stimulated culture, T plus B cells produced significantly higher titer anti-HBe than B cells alone did. These results indicate that HBcAg has a relatively higher immunogenicity in terms of antibody production as compared to HBeAg. Furthermore, HBcAg was shown to function as a T cell-dependent and -independent Ag, whereas HBeAg is T cell-dependent during chronic hepatitis virus B infection in man.     

Identification of the protocatechuate transporter gene in Sphingobium sp. strain SYK-6 and effects of overexpression on production of a value-added metabolite

Applied Microbiology and Biotechnology - Sphingobium sp. strain SYK-6 expresses the best characterized catabolic systems for lignin-derived aromatic compounds. However, the uptake systems for these...     

Genetic architecture underlying the evolutionary change of competitive ability in Asian cultivated and wild rice

Breeding of competitive cultivars has long been fraught with difficulty owing to limited knowledge of the genetic basis of competitive ability. In this study, we examined the diversity of competitive ability in Asian rice and the genetic basis of this variation. Cultivated strains and wild perennial strains have higher competitive ability than wild annual strains. Quantitative trait locus (QTL) analysis of competitive ability for three weed species was conducted in the cross between cultivated and wild annual strains, and three QTLs for general competitive ability (GCA) were identified. GCA-QTLs conferred higher competitive ability by the cultivated rice alleles and were co-located with QTLs for plant architecture and root growth, detected in the same mapping population. Furthermore, a significant change in GCA was achieved by accumulation and epistatic interaction of three QTLs. Further studies on the genetic control of competitive ability would facilitate the breeding of competitive cultivars in rice.     

An optimal stopping approach for onset of fish migration

Comprehending life history of migratory fish, onset of migration in particular, is a key biological and ecological research topic that still has not been clarified. In this paper, we propose a simple mathematical model for the onset of fish migration in the context of a stochastic optimal stopping theory, which is a new attempt to our knowledge. Finding the criteria of the onset of migration reduces to solving a variational inequality of a degenerate elliptic type. As a first step of the new mathematical modeling, mathematical and numerical analyses with particular emphasis on whether the model is consistent with the past observation results of fish migration are examined, demonstrating reasonable agreement between the theory and observation results. The present mathematical model thus potentially serves as a simple basis for analyzing onset of fish migration.