Putative inorganic carbon transport and accumulation systems associated with the CO2 concentrating mechanism in Chlamydomonas reinhardtii

The CO 2 -concentrating mechanism (CCM) of Chlamydomonas reinhardtii and other microalgal species is essential for photosynthetic growth in most natural settings. A great deal has been learned regarding the CCM in cyanobacteria, including identification of inorganic carbon transporters, while specific knowledge of analogous transporters has remained elusive in eukaryotic microalgae such as C. reinhardtii . Here, we have investigated whether the limiting-CO2 -inducible, putative ABC-type transporter, HLA3 might function as a HCO3 - transporter by evaluating the effect of pH on growth, photosynthetic Ci affinity and [14C]-Ci uptake in very low CO2 conditions following RNA interference (RNAi) knockdown of HLA3 mRNA levels in wild-type and mutant cells. The data provide compelling evidence that HLA3 is directly or indirectly involved in HCO3 - transport and provide additional evidence supporting a role for LCIA in chloroplast envelope HCO3 - transport and for LCIB in chloroplast Ci accumulation. To further elucidate the function of LCIB, we identified two ad1 suppressors that can grow in low- CO2 but die in very low- CO2. Molecular analyses revealed that both suppressors have mutations in the CAH3 gene, which encodes a thylakoid lumen localized carbonic anhydrase. Photosynthetic rates of low- CO2 acclimated suppressors under acclimation CO2 concentrations were more than two fold higher than ad1, apparently resulting from a more than 20 fold increase in the intracellular concentration of Ci as measured by direct Ci uptake. We conclude that LCIB functions downstream of CAH3 in the CCM and probably plays a role in trapping CO2 released by CAH3 dehydration of accumulated Ci. Apparently dehydration by the chloroplast stromal carbonic anhydrase CAH6 of the very high internal Ci caused by the defect in CAH3 provides Rubisco sufficient CO2 to support growth in low- CO2 acclimated cells, but not in very low- CO2 acclimated cells, even in the absence of LCIB

Novel calixpyrrole-like anion receptors

textCalix[n]pyrroles (n ≥ 4) are venerable anion receptors that are based on single pyrroles and ketones as building blocks. However, the existence of only one variable, n, that defines the nature of the systems, limits this class of macrocycles to only a few core structures. To overcome this limitation, a series of building blocks other than single pyrroles, have been applied to the construction of novel calixpyrrole-like systems. These building blocks include bipyrrole, furan, thiophene, and 1,3-bispyrrolylbenzenes. Based on bipyrrole as the sole building block, a series of calix[n]bipyrroles (n = 3, 4) was synthesized. Based on bipyrrole, furan or thiophene as co-building blocks, calix[2]bipyrrole[m]furan[n]thiophene (m + n = 2) were obtained. Based on 1,3- bispyrrolylbenzenes, calix[n]bispyrrolylbenzenes (n = 2 - 4) were synthesized. These novel calixpyrrole-like macrocycles contain different core structures than calix[n]pyrroles, and thus display different anion binding properties than their parent systems. This, in turn, means that these new systems are not only helping to the chemistry of calixpyrroles, but also giving rise to selective receptors that find applications in anion coordination chemistry.Chemistry and BiochemistryChemistr

An International Comparison of the TFP Levels of Japanese, Korean and Cinese Listed Firms

The study group on the Creation of a Productivity Database on Japanese, Chinese, and South Korean Firms at the Japan Center for Economic Research (JCER), in conjunction with the Center for Economic Institutions (CEI) of Hitotsubashi University, the Center for China and Asian Studies (CCAS) of Nippon University, and the Center for Corporate Competitiveness of Seoul National University, has compiled the East Asian Listed Companies Database 2007 (EALC 2007). In this paper, we explain the methodology and data sources used in the construction of the EALC 2007. We also conduct some descriptive analysis based on the EALC 2007. To compare the TFP level of firms in these countries, we first estimated the TFP of firms in each country using the method of Good, Nadiri and Sickles (1997). Then we estimated the relative TFP by industry in the benchmark year using Japanese industries as benchmarks and combined the estimated TFP of firms. When estimating relative TFP by industry for Korea and China, we applied the industry-level price estimates of the three countries from the ICPA project and converted industry outputs and inputs into the same currency unit (Japanese Yen). The estimation results obtained indicate that the productivity of Japanese firms is still higher than that of their Chinese and Korean counterparts but that the productivity of Korean firms is rapidly increasing, with the emergence of some firms that are now overtaking their Japanese rivals in terms of productivity, particularly in the electric machinery sector.Total Factor Productivity, International Comparison, Competitiveness

Fabrication of binder-free ultrafine WC-6CO composites by coupled multi-physical fields activation technology

A novel sintering method, named as coupled multi-physical fields activation technology, has been introduced for the forming of various material powder systems. Compared with the conventional ones, this technique presents more advantages: lower sintering temperature, shorter forming time, and remarkable inhibition of the grains coarsening. In the study, the cylinders of Φ4.0mm×4.0mm had been formed with ultrafine WC-6Co powders. The relative properties of sintered WC-6Co cemented carbides, such as hardness and the microstructures, had been obtained. The study has shown that a relative density, 97.80%, of the formed samples, could been achieved when the case of temperature 850℃, heating rate 50℃/s, pressure 75MPa and Electro-heating loop 6 times, were used. More importantly, the circumscription for the growth of grain size of WC, attributed to the effect of electrical field, renders coupled multi-physical fields activation technology applicable for getting WC-6Co cemented carbides with fine grain size and good properties