Phylogeny and evolution of chloroplast tRNAs in Adoxaceae.

Chloroplasts are semiautonomous organelles found in photosynthetic plants. The major functions of chloroplasts include photosynthesis and carbon fixation, which are mainly regulated by its circular genomes. In the highly conserved chloroplast genome, the chloroplast transfer RNA genes (cp tRNA) play important roles in protein translation within chloroplasts. However, the evolution of cp tRNAs remains unclear. Thus, in the present study, we investigated the evolutionary characteristics of chloroplast tRNAs in five Adoxaceae species using 185 tRNA gene sequences. In total, 37 tRNAs encoding 28 anticodons are found in the chloroplast genome in Adoxaceae species. Some consensus sequences are found within the Ψ-stem and anticodon loop of the tRNAs. Some putative novel structures were also identified, including a new stem located in the variable region of tRNATyr in a similar manner to the anticodon stem. Furthermore, phylogenetic and evolutionary analyses indicated that synonymous tRNAs may have evolved from multiple ancestors and frequent tRNA duplications during the evolutionary process may have been primarily caused by positive selection and adaptive evolution. The transition and transversion rates are uneven among different tRNA isotypes. For all tRNAs, the transition rate is greater with a transition/transversion bias of 3.13. Phylogenetic analysis of cp tRNA suggested that the type I introns in different taxa (including eukaryote organisms and cyanobacteria) share the conserved sequences "U-U-x2-C" and "U-x-G-x2-T," thereby indicating the diverse cyanobacterial origins of organelles. This detailed study of cp tRNAs in Adoxaceae may facilitate further investigations of the evolution, phylogeny, structure, and related functions of chloroplast tRNAs.

Histidine decarboxylase-expressing PMN-MDSC-derived TGF-ß1 promotes the epithelial-mesenchymal transition of metastatic lung adenocarcinoma.

Metastasis is a major risk for lung adenocarcinoma-related mortality. Accumulating evidence raises the possibility that anticancer therapies might be more sensitive by targeting premetastatic niches in addition to the cancer cells themselves. Here, we identified a subpopulation of metastatic lung adenocarcinoma, which was characterized by EMT-related markers such as E-cadherin, Twist, SMAD, and ß-catenin. EMT+ cases exhibited poorer prognosis than EMT- patients, reflecting the pro-metastatic features of EMT. Immunohistochemical staining decorated CD15+ PMN-MDSCs surrounding EMT+ cancer cells in lymph nodes. Metastatic tissues secreted high levels of chemokines, including CXCL1, CXCL5, and CCL2, into the circulation to recruit histidine decarboxylase (Hdc)-positive PMN-MDSCs into metastatic colonies through upregulated CXCR2. The percentage of Hdc+ PMN-MDSCs increased in the setting of metastasis. Hdc+ PMN-MDSCs obtained from EMT+ metastatic masses expressed a higher level of TGF-ß1, rather than TGF-ß2 and TGF-ß3, compared to EMT- counterparts. The depletion of Hdc+ PMN-MDSCs or downregulation of TGF-ß1 significantly decreased EMT+ percentage and, thus, hampered the metastasis process in murine models. Together, our findings suggest that metastatic tumor secretes high levels of chemokines to recruit Hdc+ PMN-MDSCs, which, in turn, express TGF-ß1 to induce cancer cells to undergo EMT at metastatic sites.

Mating Disruption of Chilo suppressalis From Sex Pheromone of Another Pyralid Rice Pest Cnaphalocrocis medinalis (Lepidoptera: Pyralidae).

The rice stem borer, Chilo suppressalis (Walker), and the rice leaf folder, Cnaphalocrocis medinalis Guenée, are two of the most destructive lepidopteran pests in rice. Since these two pyralid insects overlap in their occurrence in rice paddy fields, farmers prefer to set their pheromone-baited traps together in the rice fields for their monitoring. However, our field observation demonstrated that no male adult of C. suppressalis was captured in traps baited with commercial sex pheromone of C. suppressalis (CCS) combined with commercial sex pheromone of C. medinalis (CCM). To confirm that the C. medinalis sex pheromone component(s) interfere with the attraction of males of the rice stem borers to their conspecific females, single components of C. medinalis sex pheromone combined with CCS in traps were tested in the laboratory and rice paddy field. The results revealed that the two alcohol components in CCM, i.e., (Z)-11-octadecen-1-ol (Z11-18: OH) and (Z)-13-octadecen-1-ol (Z13-18: OH) may cause a significant reduction in capturing C. suppressalis males caused by CCS. We recommend against using these sex pheromones together in the field and suggest that Z11-18: OH and Z13-18: OH could be potential inhibitors or antagonists of C. suppressalis sex pheromone to control the rice stem borer.

A convergent route for the total synthesis of malyngamides O, P, Q, and R.

A convergent, enantioselective and general synthetic route to a class of marine natural products-malyngamides O (1), P (2), Q (3), R (4), 5''-epi-3 and 5''-epi-4-bearing a novel vinyl chloride structural motif was developed. The key steps involved construction of the vinyl chloride functionality by Wittig reaction, a DCC/HOBt-promoted amidation, an aldol reaction in the construction of the basic backbone of 1, 2, 3, 4, 5''-epi-3, and 5''-epi-4, and methylation of an enol moiety via either base/acid conditions or a Mitsunobu reaction. Moreover, the absolute configuration of the stereogenic center at C-5'' in 3 was further confirmed by synthesis of the natural product and its C-5'' epimer.

[Development of a cryosurgery & radiofrequency alternating tumor ablation device].

The combination of the cryosurgery using LN2 and intelligent RF ablation therapeutic instrument based on the theory of local destruction is introduced in this paper, and this alternating therapy is believed to have a better controlling effect on tumor ablation. In heating period, a fuzzy algorithm is used to control the RF power to realize a more smoothly heating process to the target area.

Intramolecular triplet energy transfer in donor-acceptor molecules linked by a crown ether bridge.

Bichromophoric compounds BP-C-NP and BP-C-NBD were synthesized with benzophenone chromophore (BP) as the donor, and 2-naphthyl (NP) and norbornadiene group (NBD) as the acceptor, respectively. Their intramolecular triplet energy transfer was examined. The bridges linking the donor and acceptors in these molecules involve a crown ether moiety complexing a sodium ion. Phosphorescence quenching, flash photolysis and photosensitized isomerization experiments indicate that intramolecular triplet energy transfer occurs with rate constants of about 3.3 x 10(5) and 4.8 x 10(5) s(-1) and efficiencies of about 33 and 42 % for BP-C-NP and BP-C-NBD, respectively. Theoretical calculations indicate that these molecules adopt conformations below room temperature which allow their two-end chromophores conducive to through-space energy transfer.

Nanosized particles of organically modified silica as microreactors to enhance the regioselectivity in the photocycloaddition of 9-substituted anthracenes.

[reaction: see text] Nanosized particles of modified silica with 3-ammoniumpropyl residue have been prepared and successfully used as microreactors to control the regioselectivity of the photocycloaddition of five 9-substituted anthracences [AnCH(2)N(+)(CH(3))(3)Br(-) (1), AnCH(2)COO(-)Na(+) (2), AnCH(2)CH(2)COOH (3), AnCH(2)OH (4), AnCH(3) (5), where An = 9-anthryl]. While the photocycloaddition of the five substrates in methanol mainly gave rise to their head-to-tail (h-t) photocyclomers, irradiation of 1-4 incorporated in the suspension of the modified silica in methanol almost exclusively yielded the head-to-head (h-h) photocyclomers with high quantum yields.