Chemically modified siRNAs and miRNAs bearing urea/thiourea-bridged aromatic compounds at their 3′-end for RNAi therapy

We have developed chemically modified siRNAs and miRNAs bearing urea/thiourea-bridged aromatic compounds at their 3′-end for RNAi therapy. Chemically modified RNAs possessing urea/thiourea-bridged aromatic compounds instead of naturally occurring dinucleotides at the 3′-overhang region were easily prepared in good yields and were more resistant to nucleolytic hydrolysis than unmodified RNA. siRNAs containing urea or thiourea derivatives showed the desired knockdown effect. Furthermore, modified miR-143 duplexes carrying the urea/thiourea compounds in the 3′-end of each strand were able to inhibit the growth of human bladder cancer T24 cells.     

Taxonomic Characterization and Experimental Host Ranges of Four Newly Recorded Species of Alternaria from Japan

Alternaria fungi are important plant pathogens. Here, we identified three species new to the Japanese mycoflora: Alternaria celosiae, Alternaria crassa and Alternaria petroselini. We proposed a new name for A. celosiae (E.G. Simmons & Holcomb) Lawrence, Park & Pryor, a later homonym of A. celosiae (Tassi) O. S?vul. To characterize these and a fourth morphological taxon, Alternaria alstroemeriae, which was recently added to Japan's mycoflora, an integrated species concept was tested. We determined the host range of each isolate using inoculation tests and analysed its phylogenetic position using sequences of the internal transcribed spacer rDNA. The pathogenicity of our A. alstroemeriae isolate was strictly limited to Alstroemeria sp. (Alstroemeriaceae), but the species was phylogenetically indistinguishable from other small‐spored Alternaria. Alternaria celosiae on Celosia argentea var. plumosa (Amaranthaceae) was also pathogenic to Amaranthus tricolor, to Alternanthera paronychioides and weakly to Gomphrena globosa (all Amaranthaceae) and formed a clade with the former Nimbya celosiae. Alternaria crassa on Datura stramonium (Solanaceae) was also pathogenic to Brugmansia × candida and Capsicum annuum in Solanaceae, but not to other confamilial plants; phylogenetically it belonged to a clade of large‐spored species with filamentous beaks. Morphological similarity, phylogenetic relationship and experimental host range suggested that A. crassa, Alternaria capsici and Alternaria daturicola were conspecific. Alternaria petroselini on Petroselinum crispum (Apiaceae) was pathogenic to five species in the tribe Apieae as well as representatives of Bupleureae, Coriandreae, Seliaeae and Scandiceae in Apiaceae. Both phylogeny and morphology suggested conspecificity between A. petroselini and Alternaria selini.     

Novel seed coat lignins in the Cactaceae: structure,distribution and implications for the evolution of lignin diversity

We have recently described a hitherto unsuspected catechyl lignin polymer (C‐lignin) in the seed coats of Vanilla orchid and in cacti of one genus, Melocactus (Chen et al., Proc. Natl. Acad. Sci. USA. 2012, 109, 1772‐1777.). We have now determined the lignin types in the seed coats of 130 different cactus species. Lignin in the vegetative tissues of cacti is of the normal guaiacyl/syringyl (G/S) type, but members of most genera within the subfamily Cactoidae possess seed coat lignin of the novel C‐type only, which we show is a homopolymer formed by endwise β–O–4‐coupling of caffeyl alcohol monomers onto the growing polymer resulting in benzodioxane units. However, the species examined within the genera Coryphantha, Cumarinia, Escobaria and Mammillaria (Cactoideae) mostly had normal G/S lignin in their seeds, as did all six species in the subfamily Opuntioidae that were examined. Seed coat lignin composition is still evolving in the Cactaceae, as seeds of one Mammillaria species (M. lasiacantha) possess only C‐lignin, three Escobaria species (E. dasyacantha, E. lloydii and E. zilziana) contain an unusual lignin composed of 5‐hydroxyguaiacyl units, the first report of such a polymer that occurs naturally in plants, and seeds of some species contain no lignin at all. We discuss the implications of these findings for the mechanisms that underlie the biosynthesis of these newly discovered lignin types.     

Effects of sand burial depth on the root system of Salix cheilophila seedlings in Mu Us Sandy Land, Inner Mongolia, China

Salix cheilophila Schneid. is a naturally occurring Salix species in Mu Us Sandy Land, Inner Mongolia, China. We focused on the morphological adaptability of S. cheilophila to sand dune burial. For morphological measurements, 32 S. cheilophila seedlings were removed from a community which was in the process of being buried by a shifting sand dune. Each seedling collected included the entire root system. We measured the number, length, and biomass of the adventitious roots, primary lateral roots, and taproot, and compared the morphological characteristics of the root system, including adventitious roots, for seedlings buried to various levels in the sand. The growth range of adventitious roots increased as the length of the buried portion of the main shoot increased. In addition, the total dry weight of all current-year shoots tended to increase gradually with increasing total dry weight of the adventitious roots. These results suggest that S. cheilophila tends to make use of the sedimentary sand layer that accompanies shifting sand dunes. However, there was no correlation between biomass or number of adventitious roots and the length of the buried part of the main shoot. Thus, S. cheilophila does not grow adventitious roots proportional to the buried part. These morphological characteristics of the root system, including the adventitious roots, may indicate that S. cheilophila has poor morphological adaptability to sand dune burial.     

A novel tag-free probe for targeting molecules interacting with a flavonoid catabolite

3,4-Dihydroxyphenylacetic acid (DOPAC) is one of the colonic microflora-produced catabolites of quercetin 4′-glucoside (Q4′G). Although the interaction of DOPAC with cellular proteins might be involved in its biological activity, the actual proteins have not yet been identified. In this study, we developed a novel tag-free DOPAC probe to label the targeted proteins by the copper(I)-catalyzed azide alkyne cycloaddition (CuAAC) and verified its efficacy. Various labeled proteins were detected by the DOPAC probe with the azide labeled biotin and a horseradish peroxidase (HRP)-streptavidin complex. Furthermore, a pulldown assay identified Keap1 and aryl hydrocarbon receptor (AhR) as the target proteins for the phase 2 enzyme up-regulation.