Germinal centers (GCs) support high-affinity, long-lived humoral immunity. How memory B cells develop in GCs is not clear. Through the use of a cell-cycle-reporting system, we identified GC-derived memory precursor cells (GC-MP cells) that had quit cycling and reached G0 phase while in the GC, exhibited memory-associated phenotypes with signs of affinity maturation and localized toward the GC border. After being transferred into adoptive hosts, GC-MP cells reconstituted a secondary response like genuine memory B cells. GC-MP cells expressed the interleukin 9 (IL-9) receptor and responded to IL-9. Acute treatment with IL-9 or antibody to IL-9 accelerated or retarded the positioning of GC-MP cells toward the GC edge and exit from the GC, and enhanced or inhibited the development of memory B cells, which required B cell-intrinsic responsiveness to IL-9. Follicular helper T cells (T cells) produced IL-9, and deletion of IL-9 from T cells or, more specifically, from GC T cells led to impaired memory formation of B cells. Therefore, the GC development of memory B cells is promoted by T cell-derived IL-9.

Pyrrole derivatives R 0120Copper-Catalyzed Multicomponent Reaction: Facile Access to Functionalized 5-Arylidene-2-imino-3-pyrrolines. -A large variety of sulfonyl azides, terminal alkynes and aziridines affords the representatives of a new class of pyrroline derivatives.

Phosphate transporters (PTs) mediate phosphorus uptake and are regulated at the transcriptional and posttranslational levels. In one key mechanism of posttranslational regulation, phosphorylation of PTs affects their trafficking from the endoplasmic reticulum (ER) to the plasma membrane. However, the kinase(s) mediating PT phosphorylation and the mechanism leading to ER retention of phosphorylated PTs remain unclear. In this study, we identified a rice (Oryza sativa) kinase subunit, CK2b3, which interacts with PT2 and PT8 in a yeast two-hybrid screen. Also, the CK2a3/b3 holoenzyme phosphorylates PT8 under phosphate-sufficient conditions. This phosphorylation inhibited the interaction of PT8 with PHOSPHATE TRANSPORTER TRAFFIC FACILITATOR1, a key cofactor regulating the exit of PTs from the ER to the plasma membrane. Additionally, phosphorus starvation promoted CK2b3 degradation, relieving the negative regulation of PT phosphorus-insufficient conditions. In accordance, transgenic expression of a nonphosphorylatable version of OsPT8 resulted in elevated levels of that protein at the plasma membrane and enhanced phosphorus accumulation and plant growth under various phosphorus regimes. Taken together, these results indicate that CK2a3/b3 negatively regulates PTs and phosphorus status regulates CK2a3/b3.

PHOSPHATE TRANSPORTER TRAFFIC FACILITATOR1 (PHF1) is known to regulate the plasma membrane localization of PHT1;1, a high-affinity inorganic phosphate (Pi) transporter in Arabidopsis (Arabidopsis thaliana). OsPHF1, a rice (Oryza sativa) gene homologous to AtPHF1, was isolated and found to regulate the localization of both low-and high-affinity Pi transporters to the plasma membrane. Three OsPHF1 allelic mutants carrying one-point mutations at the fifth WD-repeat motif and two at the transmembrane helix, respectively, showed arsenate resistance and severely reduced Pi accumulation. The data indicate that mutation of OsPHF1 results in the endoplasmic reticulum retention of the low-affinity Pi transporter OsPT2 and highaffinity Pi transporter OsPT8. Mutation of OsPHF1 also reduced Pi accumulation in plants exhibiting excessive shoot Pi accumulation due to the overexpression of OsPHR2. However, the transcript level of OsPHF1 itself is not controlled by OsPHR2. Overexpression of OsPHF1 increased Pi accumulation in both roots and shoots in a solution culture with Pi-supplied condition. These results indicate that the role of OsPHF1 is unique in the localization of both low-and high-affinity Pi transporters on the plasma membrane in rice and determines Pi uptake and translocation in rice. The similar function of PHF1 required to facilitate PHT1 transit through the endoplasmic reticulum between Arabidopsis and rice provides an example of expectations from what one would deduce from sequence comparisons to extend knowledge from Arabidopsis to crops.

We characterized the function of two rice phosphate (Pi) transporters: OsPHT1;9 (OsPT9) and OsPHT1;10 (OsPT10). OsPT9 and OsPT10 were expressed in the root epidermis, root hairs and lateral roots, with their expression being specifically induced by Pi starvation. In leaves, expression of the two genes was observed in both mesophyll and vasculature. High-affinity Km values for Pi transport of OsPT9 and OsPT10 were determined by yeast experiments and twoelectrode voltage clamp analysis of anion transport inXenopus oocytes expressing OsPT9 and OsPT10. Pi uptake and Pi concentrations in transgenic plants harbouring overexpressed OsPT9 and OsPT10 were determined by Pi concentration analysis and 33 P-labelled Pi uptake rate analysis. Significantly higher Pi uptake rates in transgenic plants compared with wild-type plants were observed under both high-Pi and low-Pi solution culture conditions. Conversely, although no alterations in Pi concentration were found in OsPT9 or OsPT10 knockdown plants, a significant reduction in Pi concentration in both shoots and roots was observed in double-knockdown plants grown under both high-and low-Pi conditions. Taken together, our results suggest that OsPT9 and OsPT10 redundantly function in Pi uptake.

Abscisic acid (ABA) and jasmonic acid (JA) both inhibit seed germination, but their interactions during this process remain elusive. Here, we report the identification of a 'SAPK10-bZIP72-AOC' pathway, through which ABA promotes JA biosynthesis to synergistically inhibit rice seed germination. Using biochemical interaction and phosphorylation assays, we show that SAPK10 exhibits autophosphorylation activity on the 177 th serine, which enables it to phosphorylate bZIP72 majorly on 71 st serine. The SAPK10-dependent phosphorylation enhances bZIP72 protein stability as well as the DNA-binding ability to the G-box cis-element of AOC promoter, thereby elevating the AOC transcription and the endogenous concentration of JA. Blocking of JA biosynthesis significantly alleviated the ABA sensitivity on seed germination, suggesting that ABA-imposed inhibition partially relied on the elevated concentration of JA. Our findings shed a novel insight into the molecular networks of ABA-JA synergistic interaction during rice seed germination.

In situ synthesized oxygen vacancy-enriched MoO3−x nanobelts realized excellent electrochemical performance as asymmetric supercapacitors at room/low temperature.

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