Genetic architecture of leaf photosynthesis in rice revealed by different types of reciprocal mapping populations.

The improvement of leaf net photosynthetic rate (An) is a major challenge in enhancing crop productivity. However, the genetic control of An among natural genetic accessions is still poorly understood. The high-yielding indica cultivar Takanari has the highest An of all rice cultivars, 20-30% higher than that of the high-quality japonica cultivar Koshihikari. By using reciprocal backcross inbred lines and chromosome segment substitution lines derived from a cross between Takanari and Koshihikari, we identified three quantitative trait loci (QTLs) where the Takanari alleles enhanced An in plants with a Koshihikari genetic background and five QTLs where the Koshihikari alleles enhanced An in plants with a Takanari genetic background. Two QTLs were expressed in plants with both backgrounds (type I QTL). The expression of other QTLs depended strongly on genetic background (type II QTL). These beneficial alleles increased stomatal conductance, the initial slope of An versus intercellular CO2 concentration, or An at CO2 saturation. Pyramiding of these alleles consistently increased An. Some alleles positively affected biomass production and grain yield. These alleles associated with photosynthesis and yield can be a valuable tool in rice breeding programs via DNA marker-assisted selection.

[New parameters "average flow" and "acceleration wave": comparison with current parameters in the flow volume curve].

AIM: The flow volume curve is an essential test method for diagnosis and treatment of the respiratory diseases. However, this curve depends on patient's continuous effort toward optimal expiration and it has been reported that differences in this effort may possibly result in error in flow speed. To overcome the potential error, we devised the "average flow" and the "acceleration wave" that comprehends the overall data of the expiration flow speed, and have done comparative analysis with the current parameters. METHODS: The average flow is derived by taking the integration from the beginning of the expiration to the end, and divides the integrated value by the number of data counts. Additionally, the acceleration wave is derived by taking the second degree derivative of the flow volume curve. RESULTS: The average flow showed strong correlation among healthy male and healthy female V50, obstructive index and criteria for COPD severity patients. Also, we were able to obtain the maximum acceleration from the acceleration wave. Significantly, this value showed strong correlation with the COPD patient's peak flow and average flow/peak flow. CONCLUSIONS: If the ratio of the average flow and the peak flow is below a fixed criterion, it is an obstructive lung disease, if it is above, it is possible to detect restrictive lung disease. Since the maximum acceleration rate of the acceleration wave is derived by the start of the expiration nearly up to 100 ml, it is especially possible to detect minute changes of the flow speed in large respiratory tract.

Aging exacerbates restraint stress-induced inhibition of antigen-specific antibody production in mice.

BACKGROUND: We have recently found that exposure to acute restraint stress suppresses antigen-specific antibody production, including IgE, in a murine model of allergic rhinitis. Although age-related alterations in immune responses are known, it remains unclear whether aging modulates the antibody production under stressful conditions. In this study, we set out to determine the effects of aging on antibody production under acute restraint stress in mice. METHODS: Both young and aged CBA/J mice were repeatedly sensitized intranasally with phospholipase A2 (PLA2) without adjuvants. Restraint stress was applied using uniform cylinders once a week for a continuous 8h period, on 5 occasions in total. Blood samples were taken at 0, 20 and 30 days after primary sensitization, and production of PLA2-specific antibodies and levels of IL-4, IFN-gamma, IL-10 and IL-1 beta in sera were determined by ELISA. RESULTS: Repeated intranasal sensitization with PLA2 induced PLA2-specific IgE, IgG1 and IgG2a production in aged mice. We found that exposure to restraint stress significantly inhibited production of PLA2-specific IgE, IgG1 and IgG2a in aged mice. In addition, antibody production under restraint stress decreased significantly in aged mice when compared with young mice. No IL-4, IFN-gamma, IL-10 or IL-1 beta were detected in sera from non-stressed or stressed aged mice. CONCLUSIONS: Aging exacerbates the immunosuppressive role of acute restraint stress in antigen-specific antibody production in mice.

Inhibition of Src reduces gemcitabine-induced cytotoxicity in human pancreatic cancer cell lines.

In the present study, we examined the role of Src in gemcitabine-induced cell growth suppression in human pancreatic cancer cell lines. In two human pancreatic cancer cell lines, PK-9 and MIA PaCa-2, we found that a selective Src protein tyrosine kinase inhibitor, PP2, inhibited gemcitabine-induced cell growth suppression. When dominant negative src cDNA was constitutively expressed in PK-9 cells (PK-9-Src-DN), the degree of gemcitabine-induced cell growth suppression was decreased compared with that of mock-transfected PK-9 cells. The mechanism of the inhibitory effect of gemcitabine-induced cytotoxicity was found to be the suppression of apoptosis, which was downregulated in PK-9-Src-DN cells. These results indicate that Src mediates signals that culminate in suppressing cell growth and survival in the presence of gemcitabine, at least in particular cell lines.

Immunosuppressive effect of restraint stress on the initiation of allergic rhinitis in mice.

BACKGROUND: Exposure to acute stressors modulates both innate and acquired immune function. However, little is known about whether stress has the potential to modulate the pathogenesis of allergic rhinitis. OBJECTIVES: To determine the effects of acute restraint stress on the initiation of allergic rhinitis in a murine model. METHODS: CBA/J mice were repeatedly intranasally sensitized with phospholipase A2 (PLA2) from honeybee venom without adjuvant. Restraint stress was applied using uniform cylinders once a week for a continuous 8-hour period, on five occasions in total. Production of PLA2-specific antibodies and degree of nasal and blood eosinophilia were compared between stressed and control mice. RESULTS: Repeated intranasal sensitization with PLA2 induced PLA2-specific IgE and marked eosinophilia in both the nose and blood in CBA/J mice. Exposure to restraint stress significantly inhibited production of PLA2-specific IgE, IgG1 and IgG2a. Conversely, the stress exerted no significant effect on eosinophilia. CONCLUSIONS: Exposure to acute restraint stress inhibits antigen-specific antibody production, but not local or systemic eosinophilia. The results of this study suggest that acute stress has the potential to modulate the initiation of allergic rhinitis.