Recovery of aSasa tsuboiana population after mass flowering and death

The recovery process of aSasa tsuboiana population after a mass flowering and death in 1977 was investigated by 15 years of observation in the Hira Mountains, Kinki district, western Japan. Seed production was high (6600–13 800 seeds m⁻² inSasa plots and 3900 seeds m⁻² in a forest plot) but emergent seedling density was low (14–21 seedlings m⁻²), probably because of seed predation byMicrotus montebelli occurring between seed shedding and the next spring. The seedling density had decreased further by the next year and theS. tsuboiana population recovered from only a limited number of seedlings. In spite of such a low initial density, theS. tsuboiana population was able to regenerate successfully and attained the previous full stand height in 7–16 years.Miscantbus sinensis invaded and delayed the recovery ofS. tsuboiana in one plot, butS. tsuboiana became dominant as it caught up with the height ofM. sinensis. Seedling growth patterns, such as frequent tillering, the onset of rhizome extension in the early stage of seedling growth and frequent culm production from rhizomes, played important roles in the successful regeneration ofS. tsuboiana.     

Camellidins,Antifungal Saponins Isolated from Camellia japonica

Two triterpenoid saponins were isolated from an aqueous or a methanolic extract of camellia (Camellia japonica) leaf. They had an antifungal activity characterized by abnormal germination of conidia. These saponins were composed of 3βhydroxy-18β-acetoxy-28-norolean-12-en-16-one or 3β, 8β-dihydroxy-28-norolean-12-en-16-one as aglycon, and d-glucuronic acid, dglucose and two moles of dgalactose as the sugar moiety. The authors have named these new saponins “Camellidin,” which might have value for studies in the fields of phytopathology and biochemistry.     

Reduced aleurone {alpha}-amylase production in aged wheat seeds is accompanied by lower levels of high-pI [IMAGE]-amylase transcripts and reduced response to gibberellic acid

With the aim of determining the level at which ageing exerts its effect on the expression of -amylase, GA3 regulation of -amylase production was studied in isolated aleurone layers from aged wheat seeds. GA3-induced -amylase activity was lower in the tissue from aged seeds than in controls. However, the proportion of ³⁵S-methionine incorporated into -amylase was higher in the aged than in control tissue. The pattern of -amylase isoforms was resolved by isoelectric focusing and showed that two isogroups were present with the activity of the high-pI isogroup being higher in the control than in the aged lot. These apparently contradictory results may be explained in terms of differences in isozyme expression. Studies on the expression of -amylase genes indicated a reduction in the level of high-pI mRNA in aged tissue. Dose-response curves showed lower GA3-responsiveness of aleurone layers from aged seeds as compared to the controls. From these results, it is proposed that the diminished capacity of -amylase production in aleurone from aged seeds is apparently due to a decrease in the expression of the high-pI -amylase genes, and this reduction is associated with a decrease in the response to GA3.Key words: Seed ageing, wheat aleurone, gibberellic acid, -amylase isozymes, gene expression.      

An association of 27- and 40-kDa molecules with glycolipids that bind A-B bacterial enterotoxins to cultured cells

It is well recognized that the Shiga-like toxins (Stxs) preferentially bind to Gb3 glycolipids and the cholera toxin (CT) and heat-labile enterotoxin (LTp) bind to GM1 gangliosides. After binding to the cell surface, A-B bacterial enterotoxins have to be internalized by endocytosis. The transport of the toxin-glycolipid complex has been documented in several manners but the actual mechanisms are yet to be clarified. We applied a heterobifunctional cross-linker, sulfosuccinimidyl-2-(p-azidosalicylamido)-1,3'-dithiopropionate (SASD), to detect the membrane proteins involved in the binding and the transport of A-B bacterial enterotoxins in cultured cells. Both Stx1 and Stx2 bound to the detergent-insoluble microdomain (DIM) of Vero cells and Caco-2 cells, which were susceptible to the toxin, but neither was bound to insusceptible CHO-K1 cells. Both CT and LTp bound to the DIM of Vero cells, Caco-2 cells, and CHO-K1 cells. In a cross-linking experiment, Stx1 cross-linked only with a 27-kDa molecule, while Stx2, which was more potently toxic than Stx1, cross-linked with 27- and 40-kDa molecules of Vero cells as well as of Caco-2 cells; moreover, no molecules were cross-linked with the insusceptible CHO-K1 cells. LTp was cross-linked only to the 27-kDa molecule of these three cell types but the CT, which was more toxic than LTp, was also cross-linked with 27- and 40-kDa molecules of Vero cells, Caco-2 cells, and CHO-K1 cells. The 27- and the 40-kDa molecules might play a role in the endocytosis and retrograde transport of A-B bacterial enterotoxins.     

Hydroxylation of para-chlorotoluene by model complexes of cytochrome P-450

Hydroxylation of p-chlorotoluene with heminthiol complexes, Fenton's system and Udenfriend's system was studied and the complexes assessed as models of cytochrome P-450 monooxygenases. Five species of possible hydroxylation products of p-chlorotoluene, namely, p-chlorobenzyl alcohol, 2-chloro-5-methylphenol, p-chlorobenzaldehyde, 4-chloro-2-methylphenol and 5-chloro-2-methylphenol, were studied using high performance liquid chromatography. The oxidation reactions were characterized by the yields of hydroxylation products and the product ratio. The system consisting of hemin and cysteine ethyl ester as well as Udenfriend's system gave relatively high hydroxylation yields and the former only induced a methyl migration during hydroxylation (methyl NIH shift). However, neither Fenton's nor Udenfriend's systems induced a methyl NIH shift. The hemin-thiol complex is thus concluded to be a good chemical model of cytochrome P-450 monooxygenases.     

Distinctiveness of the genomic sequence of Shiga toxin 2-converting phage isolated from Escherichia coli O157:H7 Okayama strain as compared to other Shiga toxin 2-converting phages

Shiga toxin 2-converting phage was isolated from Escherichia coli O157:H7 associated with an outbreak that occurred in Okayama, Japan in 1996 (M. Watarai, T. Sato, M. Kobayashi, T. Shimizu, S. Yamasaki, T. Tobe, C. Sasakawa and Y. Takeda, Infect. Immun. 61 (1998) 3210-3204). In this study, we analyzed the complete nucleotide sequence of Shiga toxin 2-converting phage, designated Stx2phi-I, and compared it with three recently reported Stx2-phage genomes. Stx2phi-I consisted of 61,765 bp, which included 166 open reading frames. When compared to 933W, VT2-Sakai and VT2-Sa phages, six characteristic regions (regions I-VI) were found in the Stx2 phage genomes although overall homology was more than 95% between these phages. Stx2phi-I exhibited remarkable differences in these regions as compared with VT-2 Sakai and VT2-Sa genes but not with 933W phage. Characteristic repeat sequences were found in regions I-IV where the genes responsible for the construction of head and tail are located. Regions V and VI, which are the most distinct portion in the entire phage genome were located in the upstream and downstream regions of the Stx2 operons that are responsible for the immunity and replication, and host lysis. These data indicated that Stx2phi-I is less homologous to VT2-Sakai and VT2-Sa phages, despite these three phages being found in the strains isolated at the almost same time in the same geographic region but closely related to 933W phage which was found in the E. coli O157 strain 933W isolated 14 years ago in a different geographic area.     

The Bright Side and Dark Side of Workplace Social Capital: Opposing Effects of Gender on Overweight among Japanese Employees

Background

A growing number of studies have sought to examine the health associations of workplace social capital; however, evidence of associations with overweight is sparse. We examined the association between individual perceptions of workplace social capital and overweight among Japanese male and female employees.

Methodology/Principal Findings

We conducted a cross-sectional survey among full-time employees at a company in Osaka prefecture in February 2012. We used an 8-item measure to assess overall and sub-dimensions of workplace social capital, divided into tertiles. Of 1050 employees, 849 responded, and 750 (624 men and 126 women) could be linked to annual health check-up data in the analysis. Binomial logistic regression models were used to calculate odds ratios and 95% confidence intervals for overweight (body mass index: ≥25 kg/m², calculated from measured weight and height) separately for men and women. The prevalence of overweight was 24.5% among men and 14.3% among women. Among men, low levels of bonding and linking social capital in the workplace were associated with a nearly 2-fold risk of overweight compared to high corresponding dimensions of social capital when adjusted for age, sleep hours, physiological distress, and lifestyle. In contrast, among women we found lower overall and linking social capital to be associated with lower odds for overweight even after covariate adjustment. Subsequently, we used multinomial logistic regression analyses to assess the relationships between a 1 standard deviation (SD) decrease in mean social capital and odds of underweight/overweight relative to normal weight. Among men, a 1-SD decrease in overall, bonding, and linking social capital was significantly associated with higher odds of overweight, but not with underweight. Among women, no significant associations were found for either overweight or underweight.

Conclusions/Significance

We found opposite gender relationships between perceived low linking workplace social capital and overweight among Japanese employees.