Bioscience, Biotechnology, and Biochemistry最新文献

Strigolactones (SLs) are apocarotenoid plant hormones that regulate shoot branching. The natural SLs can be divided into two groups, canonical and non-canonical SLs according to those chemical structures. In a model plant, Arabidopsis thaliana, it has been thought to produce only non-canonical SLs. Moreover, in rice, it was suggested that canonical-SL such as 4-deoxyorobanchol (4DO) does not have a critical role in shoot branching inhibition. In this report, to understand the potential of canonical-SL in shoot branching inhibition pathway in Arabidopsis, SL biosynthetic genes involved in canonical-SL production in other plant species were individually expressed in Arabidopsis. Our data clearly demonstrate that 5-deoxystrigol, but not 4DO, can inhibit shoot branching in Arabidopsis. Moreover, the results confirmed the important role of CLA methyltransferase (CLAMT) in shoot branching inhibition pathway in Arabidopsis.

Coenzyme Q (CoQ) or ubiquinone functions as an electron transporter in the electron transport system in both prokaryotes and eukaryotes. The isoprenyl side chain of CoQ is modified in some organisms, especially in fungi, for optimal electron transport performance under various conditions. In this study, we investigated the side chain saturated dihydro CoQ (CoQ10(H2)) in Aureobasidium pullulans EXF-150, Sydowia polyspora NBRC 30562, and naturally isolated Plowrightia sp. A37, all of which are melanized Dothideomycetes species within Ascomycota, and also in filamentous fungi Aspergillus oryzae and A. terreus. Plowrightia sp. A37 produced the rarely synthesized tetrahydro type CoQ10(H4), especially in glucose-rich medium, during extended cultivation in contrast to CoQ10(H2) in time-limited cultivation. Using liquid chromatography-mass spectrometry, we identified demethoxyubiquinone-H2 (DMQ(H2)) as an indicative intermediate that suggests that the side chain saturation of CoQ occurs after the formation of DMQ and not always in the last step as previously considered.

An increase in the number of drug-resistant microbes is a major threat to human health. Bacterial drug resistance is mostly mediated by biofilm formation. In this study, the culture filtrate from the edible mushroom, Pleurotus ostreatus, was fractionated to isolate compounds that inhibit the biofilm formation of six pathogenic bacteria. Notably, we isolated compounds 1-6 using bioassay-guided chromatographic separations. Spectroscopic and X-ray diffraction analyses identified 1 as a novel fused bicyclic pyrone-furan, named pleuropyronine, whereas 2-6 were known polyketides. Pleuropyronine inhibited biofilm formation in four Gram-negative bacteria, with IC50 values ranging from 5.4 to 8.7 µg/mL, whereas 2-6 exhibited IC50 values between 1.0 and 5.3 µg/mL against five bacteria. Additionally, pleuropyronine bioactivity was confirmed by the inhibition of exopolysaccharide and biofilm formation induced by C6-homoserine lactone. Thus, this may serve as a pioneering study on the pharmacological potential of isolated compounds, offering valuable insights for future research.

The toxin-antitoxin (TA) genetic module controls various bacterial events. Novel toxins with different functions are still being discovered. This study aimed to determine whether the ECs3274-ECs3275 gene pair encoded by enterohemorrhagic Escherichia coli O157 functions as a TA system. To characterize this putative TA system, we analyzed the growth of E. coli expressing ECs3274, ECs3275, or both; the interaction between ECs3274 and ECs3275 using bacterial adenylate cyclase two-hybrid assays; and the DNA-binding ability of ECs3274 using gel-mobility shift assays. We observed that the ECs3274 antitoxin interacted with the ECs3275 toxin, was destabilized by Lon protease, and repressed its promoter activity via its helix-turn-helix (HTH) motif. These properties are consistent with those of typical type II TA antitoxins. Interestingly, ECs3275 has an HTH motif not observed in other TA toxins and is necessary for ECs3275 toxicity, suggesting that ECs3275 may exert its toxicity by regulating the expression of specific genes.

Recombinant protein production in prokaryotic and eukaryotic cells is a fundamental technology for both research and industry. Achieving efficient protein synthesis is key to accelerating the discovery, characterization, and practical application of proteins. This review focuses on recent advances in recombinant protein production and strategies for more efficient protein production, especially using Escherichia coli and Saccharomyces cerevisiae. Additionally, this review summarizes the development of various functional peptide tags that can be employed for protein production, modification, and purification, including translation-enhancing peptide tags developed by our research group.

Thermophilic actinomycetes significantly contribute to the terrestrial carbon cycle via the rapid degradation of lignocellulosic polysaccharides in composts. In this study, a genome-editing system was constructed for the thermophilic actinomycete Streptomyces thermodiastaticus K5 strain, which was isolated from compost. The genome-editing plasmid (pGEK5) harboring nickase Cas9 was derived from the high-copy plasmid pL99 and used for the K5 strain. It was found that pGEK5 could easily be lost from the transformed clone through cultivation on apramycin-free medium and spore formation, enabling its reuse for subsequent genome-editing cycles. With the aid of this plasmid, mutations were sequentially introduced to 2 uracil-DNA glycosylase genes (Udg1 and Udg2) and 1 β-glucosidase gene (Bgl1). Thus, the genome-editing system using pGEK5 enables us to start the functional modification of this thermophilic actinomycete, especially for improved conversion of lignocellulosic biomass.

Plants, as sessile organisms, must adapt to environmental changes and defend themselves against biotic stress, including pathogen attack. Their immune responses entail recognition of pathogen patterns, activation of defense mechanisms, and accumulation of various antimicrobial compounds. Eugenol, abundant in basil, has antibacterial properties and enhances plant resistance to viruses. However, its priming effects on biotrophic pathogens remain unclear. Thus, we investigated whether eugenol and basil essential oils could prime Arabidopsis thaliana immunity against the hemi-biotroph Pseudomonas syringae pv. maculicola (Psm) MAFF302723. Our study revealed that both eugenol and basil essential oils functioned as priming agents, mitigating disease symptoms upon Psm infection. This priming effect occurred via NPR1-dependent but salicylic acid-independent signaling. Moreover, our gene expression analysis suggested that priming might influence jasmonic acid/ethylene signaling. These findings underscore the potential of employing natural compounds such as basil essential oil to bolster plant immune responses in sustainable agricultural practices.

We previously reported that choline chloride and N-allylglycine stimulate photosynthesis in wheat protoplasts. Treatment of Arabidopsis thaliana and Brassica rapa plants with both compounds promoted growth and photosynthesis. To clarify the relationship between the enhancement of photosynthesis and increased growth, A. thaliana T87 cells, which show photosynthesis-dependent growth, and YG1 cells, which use sugar in the medium for growth, were treated with choline chloride or N-allylglycine. Only the T87 cells showed increased growth, suggesting that choline chloride and N-allylglycine promote growth by increasing photosynthetic activity. Transcriptome analysis using choline chloride- and N-allylglycine-treated plants showed that the most abundant transcripts corresponded to photosynthetic electron transfer-related genes among the genes upregulated by both compounds. Furthermore, the compounds also upregulate genes encoding transcription factors that may control the expression of these photosynthetic genes. These results suggest that choline chloride and N-allylglycine promote photosynthesis through increased expression of photosynthetic electron transfer-related genes.

Essential amino acids (EAAs) are important for the maintenance of brain functions. Therefore, the yeast Saccharomyces cerevisiae that accumulates EAAs would help elderly people ingest appropriate levels of EAAs, which in turn could slow neurodegeneration, extend the healthy lifespan, and improve quality of life. Here, we isolated 2 mutant strains, ETH-80 and ETH-129, that accumulate the EAA methionine. Both strains were derived from a diploid laboratory yeast by conventional mutagenesis and carry a novel mutation in the MET13 gene, which encodes the Ser443Phe variant of methylenetetrahydrofolate reductase. Enzymatic analysis revealed that the Ser443Phe substitution abolished the sensitivity to S-adenosyl methionine (SAM)-mediated inhibition even in the presence of 2 m m SAM, while increasing the activity for NADPH-dependent reduction. Furthermore, yeast cells expressing the Ser443Phe variant showed a 4-fold increase in intracellular methionine content compared to the wild-type Met13. These findings will be useful for the future development of methionine-accumulating yeast strains.

Cold atmospheric plasma (CAP) irradiation exhibits a sterilizing effect without causing thermal denaturation or leaving behind residual toxicants. CAP also has potential applications in various fields, including agriculture, leading to research efforts in recent years. This study investigated the effects of CAP on the seed germination rate of spinach (Spinacia oleracea), which typically has a low seed germination rate. Our results confirmed that irradiation with N2-CAP and Air-CAP significantly enhanced the germination rate of spinach seeds. Notably, we discovered that CAP irradiation promoted germination even in spinach seeds coated with a fungicide (thiuram) and a disinfectant (Captan), which are commonly used. Additionally, we examined whether the interval between CAP irradiation and the subsequent germination-induction treatment influenced the germination efficiency. We found that the germination-promoting effect of CAP on spinach seeds persisted for at least 30 days, demonstrating the high utility and practicality of CAP in the agricultural sector.