Photocatalytic Dinitrogen Fixation with Water on Bismuth Oxychloride in Chloride Solutions for Solar-to-Chemical Energy Conversion.

Ammonia is an indispensable chemical. Photocatalytic NH3 production via dinitrogen fixation using water by sunlight illumination under ambient conditions is a promising strategy, although previously reported catalysts show insufficient activity. Herein, we showed that ultraviolet light irradiation of a semiconductor, bismuth oxychloride with surface oxygen vacancies (BiOCl-OVs), in water containing chloride anions (Cl-) under N2 flow efficiently produces NH3. The surface OVs behave as the N2 reduction sites by the photoformed conduction band electrons. The valence band holes are consumed by self-oxidation of interlayer Cl- on the catalyst. The hypochloric acid (HClO) formed absorbs ultraviolet light and undergoes photodecomposition into O2 and Cl-. These consecutive photoreactions produce NH3 with water as the electron donor. The Cl- in solution compensates for the removed interlayer Cl- and inhibits catalyst deactivation. Simulated sunlight illumination of the catalyst in seawater stably generates NH3 with 0.05% solar-to-chemical conversion efficiency, thus exhibiting significant potential of the seawater system for artificial photosynthesis.

BCR-ABL induces tyrosine phosphorylation of YAP leading to expression of Survivin and Cyclin D1 in chronic myeloid leukemia cells.

In the present study, we studied downstream signals of BCR-ABL with regard to Src family kinases and YAP, a transcription cofactor and an effector of the Hippo pathway. We first checked the phosphorylation status of YAP and found that it was constitutively phosphorylated at tyrosine 357 in CML-derived cell lines (TCC-S and K562) but not in AML-derived cell lines (HL-60 and KG-1a). Treatment with imatinib or RK-20449 inhibited cell growth and decreased tyrosine phosphorylation of YAP in both CML lines. Expression of Survivin or Cyclin D1 was decreased in TCC-S, but not in either HL-60 or KG-1a. Furthermore, we established BCR-ABL stable transfectant and control empty vector transfectant from TF-1, a factor-dependent human erythroleukemia cell line, to verify our results obtained with CML cell lines. YAP was phosphorylated at Y357 constitutively in BCR-ABL stable transfectant but not in control transfectant, and treatment with imatinib or RK-20449, a Src family kinase-specific inhibitor, inhibited cell growth, YAP tyrosine phosphorylation, and expression of Cyclin D1 in BCR-ABL stable transfectant. These results suggest that BCR-ABL induces tyrosine phosphorylation of YAP presumably through Src family kinases, which results in expression of Survivin and Cyclin D leading to leukemogenesis in CML cells.

A 50-kilodalton Cry2A peptide is lethal to Bombyx mori and Lymantria dispar.

The Cry2Aa3 gene was introduced into asporogenic Bacillus thuringiensis, and the synthesized protoxin killed Bombyx mori and Lymantria dispar larvae. Chymotrypsin hydrolyzed the linkages between 49Tyr/Val50 and 145Lys/Ser146 in the protoxin, and 50- and 58-kDa fragments were generated, respectively. Both peptides killed the larvae of both insects.

Characterization of a novel plasma membrane protein, expressed in the midgut epithelia of Bombyx mori, that binds to Cry1A toxins.

We describe the properties of a novel 252-kDa protein (P252) isolated from brush border membranes of Bombyx mori. P252 was found in a Triton X-100-soluble brush border membrane vesicle fraction, suggesting that it may be a component of the midgut epithelial cell membrane. P252 was purified to homogeneity, and the amino acid sequence of two internal peptides was determined, but neither of the peptides matched protein sequences in the available databases. The apparent molecular mass of the purified protein was estimated by denaturing gel electrophoresis to be 252 kDa, and it migrated as a single band on native gels. However, gel filtration chromatography indicated an apparent mass of 985 kDa, suggesting that P252 may exist as a homo-oligomer. The associations of P252 with Cry1Aa, Cry1Ab, and Cry1Ac were specific, and K(d) constants were determined to be 28.9, 178.5, and 20.0 nM, respectively. A heterologous competition assay was also done. P252 did not exhibit Leu-pNA hydrolysis activity, and binding to the Cry1A toxins was not inhibited by GalNAc. Binding assays of P252 with various lectins indicated the presence of three antennal N-linked high-mannose-type as well as O-linked mucin-type sugar side chains. While the function of P252 is not yet clear, we propose that it may function with Cry1A toxins during the insecticidal response and/or Cry toxin resistance mechanism.