Rice yield enhancement by elevated CO2 is reduced in cool weather

The projected increase of atmospheric CO₂ concentration ([CO₂]) is expected to increase rice yield, but little is known of the effects of [CO₂] at low temperature, which is the major constraint to growing rice in cool climates. We grew rice under two levels of [CO₂] (ambient and elevated by 200 μmol mol^?1) and two nitrogen (N) fertilization regimes in northern Japan in 2003 (cool weather) and 2004 (warm weather) in the field in a free‐air CO₂ enrichment (FACE) system. Elevated [CO₂] significantly increased grain yield in both years in both N regimes, but the magnitude of the increase differed between years: 6% in 2003 vs. 17% in 2004, with a significant interaction between [CO₂] and year. This difference resulted from responses of spikelet number and ripening percentage to elevated [CO₂]. Enhancement of dry matter production and N uptake at heading by elevated [CO₂] was smaller in 2003 than in 2004, although at maturity there was no difference between years. No significant interaction between N regime and [CO₂] was detected in yield and yield components. The results suggest that yield gain due to elevated [CO₂] can be reduced by low temperature.     

Effects of Surfactant Protein-A on the Interaction of Pneumocystis murina with its Host at Different Stages of the Infection in Mice

ABSTRACT. We examined the effects of surfactant protein A (SP-A), a collectin, on the interaction of Pneumocystis murina with its host at the beginning, early to middle, and late stages of infection. Pneumocystis murina from SP-A wild-type (WT) mice inoculated intractracheally into WT mice (WT_S-WT_R) adhered well to alveolar macrophages, whereas organisms from SP-A knockout (KO) mice inoculated into KO mice (KO_S-KO_R) did not. Substitution of WT mice as the source of organisms (WT_S-KO_R) or recipient host macrophages (KO_S-WT_R) restored adherence to that found with WT_S-WT_R mice. In contrast, when immunosuppressed KO and WT mice were inoculated with P. murina from a homologous source (KO_S-KO_R, WT_S-WT_R) or heterologous source (WT_S-KO_R, KO_S-WT_R) and followed sequentially, WT_S-KO_R mice had the highest levels of infection at weeks 3 and 4; these mice also had the highest levels of the chemokine macrophage inflammatory protein-2 and neutrophils in lavage fluid at week 3. Surfactant protein-A administered to immunosuppressed KO_S-KO_R mice with Pneumocystis pneumonia for 8 wk as a therapeutic agent failed to lower the organism burden. We conclude that SP-A can correct the host immune defect in the beginning of P. murina infection, but not in the middle or late stages of the infection.     

Muscle Differentiation in Cultured Pineal Body Cells of Neonatal Rats

Dissociated cells of pineal bodies of new-born rats were cultured to see what cell types would be differentiated during culture in vitro for about 4 weeks. In early stages of culture, about 10 days after inoculation, flattened cells with piliform processes, small round cells and small bubbling cells were distinguishable in the cultures. After about 2 weeks, neuronal cells with axon-like processes and multinuclear muscle-like cells were differentiated. On further culture, the latter cells differentiated into mature striated myotubes. The developmental origin of myotube formed in cell cultures of pineal body is discussed.