捕食者-被食者の相互作用における被食者行動の機能的役割: 沿岸性ミジンコとトンボ幼虫を用いた研究

要約のみTohoku University占部城太郎課

Characterization of the promoter region of biosynthetic enzyme genes involved in Berberine biosynthesis in Coptis japonica

The presence of alkaloids is rather specific to certain plant species. However, berberine, an isoquinoline alkaloid, is relatively broadly distributed in the plant kingdom. Thus, berberine biosynthesis has been intensively investigated, especially using Coptis japonica cell cultures. Almost all biosynthetic enzyme genes have already been characterized at the molecular level. Particularly, two transcription factors (TFs), a plant-specific WRKY-type TF, CjWRKY1, and a basic helix-loop-helix TF, CjbHLH1, were shown to comprehensively regulate berberine biosynthesis in C. japonica cells. In this study, we characterized the promoter region of some biosynthetic enzyme genes and associated cis-acting elements involved in the transcriptional regulation via two TFs. The promoter regions of three berberine biosynthetic enzyme genes (CYP80B2, 4′OMT and CYP719A1) were isolated, and their promoter activities were dissected by a transient assay involving the sequentially truncated promoter::luciferase (LUC) reporter constructs. Furthermore, transactivation activities of CjWRKY1 were determined using the truncated promoter::LUC reporter constructs or constructs with mutated cis-elements. These results suggest the involvement of a putative W-box in the regulation of biosynthetic enzyme genes. Direct binding of CjWRKY1 to the W-box DNA sequence was also confirmed by an electrophoresis mobility shift assay and by a chromatin immunoprecipitation assay. In addition, CjbHLH1 also activated transcription from truncated 4′OMT and CYP719A1 promoters independently of CjWRKY1, suggesting the involvement of a putative E-box. Unexpected transcriptional activation of biosynthetic enzyme genes via a non-W-box sequence and by CjWRKY1 as well as the possible involvement of a GCC-box in berberine biosynthesis in C. japonica are discussed

Microbial Diversity in the Edible Gall on White Bamboo Formed by the Interaction between Ustilago esculenta and Zizania latifolia

An edible gall is formed between the third and fourth nodes beneath the apical meristem near the base of Zizania latifolia shoots. This gall is harbored by and interacts with the smut fungus Ustilago esculenta. The gall is also a valuable vegetable called “white bamboo,” jiaobai or gausun in China and makomotake in Japan. Five samples of the galls harvested at different stages of swelling were used to isolate microorganisms by culturing. Isolated fungal and bacterial colonies were identified by DNA sequencing and matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry, respectively. Several strains of U. esculenta as well as 6 other species of fungi and 10 species of bacteria were isolated. The microbiome was also evaluated by simple and outlined DNA profiling with automated rRNA intergenic spacer analysis (ARISA), and the amount of DNA of U. esculenta was determined by qPCR. At least 16 species of fungi and 40 species of bacteria were confirmed by ARISA of the overall sample. Interestingly, the greatest bacterial diversity, i.e., 18 species, was observed in the most mature sample, whereas the fungal diversity observed in this sample, i.e., 4 species, was rather poor. Based on qPCR, U. esculenta occurred in samples from all stages; however, the abundance of U. esculenta exhibited unique U-shaped relationships with growth. These results may explain why the interaction between U. esculenta and Z. latifolia also influences the unique microbial diversity observed throughout the growth stages of the swollen shoot, although the limited sample size does not allow conclusive findings

Unique growth stage-dependent anti-inflammatory and immunostimulating effects of white bamboo (makomotake) on RAW264 macrophages shown by no production

White bamboo is the swollen stem of Zizania latifolia parasitized by the smut fungus Ustilago esculenta. Five samples of galls were harvested at different stages of swelling, along with young seedlings of Z. latifolia and isolated colonies of U. esculenta. The inhibition capacity of boiling water or 50% ethanol extracts on NO release by RAW264 cells, which was stimulated with lipopolysaccharide, was evaluated as anti-inflammatory activity, while the NO induction capacity was evaluated as immunostimulatory activity. Total polyphenol (TPP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity were also measured. The anti-inflammatory effect, as well as TPP and DPPH, was comprehensively detected in the ethanol extracts. The immunostimulating activity was observed in the boiled extracts at different levels, depending on the swelling stage, and was especially high in the top (apical) part. These data may indicate that functional components could be dynamically induced by interactions between Z. latifolia and U. esculenta