نتائج البحث - "Kazuki Saito"

1

A multimodal metabolomics approach using imaging mass spectrometry and liquid chromatography-tandem mass spectrometry for spatially characterizing monoterpene indole alkaloids secreted from roots

المؤلفون: Ryo Nakabayashi, Mai Uzaki, Kiminori Toyooka, Noriko Takeda-Kamiya, Kazuki Saito, Yutaka Yamada, Tetsuya Mori, Takashi Nirasawa

المصدر: Plant Biotechnol (Tokyo)

مصطلحات موضوعية: Indole test, Original Paper, Ajmalicine, Chromatography, Metabolite, Plant Science, Catharanthine, Biology, Mass spectrometry, Mass spectrometry imaging, chemistry.chemical_compound, Metabolomics, chemistry, Liquid chromatography–mass spectrometry, Agronomy and Crop Science, Biotechnology

الوصف: Plants release specialized (secondary) metabolites from their roots to communicate with other organisms, including soil microorganisms. The spatial behavior of such metabolites around these roots can help us understand roles for the communication; however, currently, they are unclear because soil-based studies are complex. Here, we established a multimodal metabolomics approach using imaging mass spectrometry (IMS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) to spatially assign metabolites under laboratory conditions using agar. In a case study using Catharanthus roseus, we showed that 58 nitrogen (N)-containing metabolites are released from the roots into the agar. For the metabolite assignment, we used (15)N-labeled and non-labeled LC-MS/MS data, previously reported. Four metabolite ions were identified using authentic standard compounds as derived from monoterpene indole alkaloids (MIAs) such as ajmalicine, catharanthine, serpentine, and yohimbine. An alkaloid network analysis using dot products and spinglass methods characterized five clusters to which the 58 ions belong. The analysis clustered ions from the indolic skeleton-type MIAs to a cluster, suggesting that other communities may represent distinct metabolite groups. For future chemical assignments of the serpentine community, key fragmentation patterns were characterized using the (15)N-labeled and non-labeled MS/MS spectra.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e34fd60cbe3a3bef1e08c4b567a2ca66Test
https://doi.org/10.5511/plantbiotechnology.21.0504aTest

2

CRISPR/Cas9-mediated disruption of the PYRROLIDINE KETIDE SYNTHASE gene reduces the accumulation of tropane alkaloids in Atropa belladonna hairy roots

المؤلفون: Fumihito Hasebe, Kazuki Saito, Honoka Yuba, Takashi Hashimoto, Tsubasa Shoji, Nobutaka Funa

المصدر: Bioscience, Biotechnology, and Biochemistry. 85:2404-2409

الوصف: Tropane alkaloids, including clinically important hyoscyamine and scopolamine, are produced in the roots of medicinal plant species, such as Atropa belladonna, from the Solanaceae family. Recent molecular and genomic approaches have advanced our understanding of the metabolic enzymes involved in tropane alkaloid biosynthesis. A noncanonical type III polyketide synthase, pyrrolidine ketide synthase (PYKS) catalyzes a two-step decarboxylative reaction, which involves imine–ketide condensation indispensable to tropane skeleton construction. In this study, we generated pyks mutant A. belladonna hairy roots via CRISPR/Cas9-mediated genome editing and analyzed the metabolic consequences of the loss of PYKS activity on tropane alkaloids, providing insights into a crucial role of the scaffold-forming reaction in the biosynthetic pathway.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ed19d6f1d619a4c094efe4876af47700Test
https://doi.org/10.1093/bbb/zbab165Test

3

Characterization of C‐26 aminotransferase, indispensable for steroidal glycoalkaloid biosynthesis

المؤلفون: Haruka Miyachi, Bunta Watanabe, Masaharu Mizutani, Naoyuki Umemoto, Toshiya Muranaka, Kazuki Saito, Masaru Nakayasu, Ryota Akiyama, Kiyoshi Ohyama, Hyoung Jae Lee, Yukihiro Sugimoto

المصدر: The Plant Journal. 108:81-92

الوصف: Steroidal glycoalkaloids (SGAs) are toxic specialized metabolites found in members of the Solanaceae, such as Solanum tuberosum (potato) and Solanum lycopersicum (tomato). The major potato SGAs are α-solanine and α-chaconine, which are biosynthesized from cholesterol. Previously, we have characterized two cytochrome P450 monooxygenases and a 2-oxoglutarate-dependent dioxygenase that function in hydroxylation at the C-22, C-26 and C-16α positions, but the aminotransferase responsible for the introduction of a nitrogen moiety into the steroidal skeleton remains uncharacterized. Here, we show that PGA4 encoding a putative γ-aminobutyrate aminotransferase is involved in SGA biosynthesis in potatoes. The PGA4 transcript was expressed at high levels in tuber sprouts, in which SGAs are abundant. Silencing the PGA4 gene decreased potato SGA levels and instead caused the accumulation of furostanol saponins. Analysis of the tomato PGA4 ortholog, GAME12, essentially provided the same results. Recombinant PGA4 protein exhibited catalysis of transamination at the C-26 position of 22-hydroxy-26-oxocholesterol using γ-aminobutyric acid as an amino donor. Solanum stipuloideum (PI 498120), a tuber-bearing wild potato species lacking SGA, was found to have a defective PGA4 gene expressing the truncated transcripts, and transformation of PI 498120 with functional PGA4 resulted in the complementation of SGA production. These findings indicate that PGA4 is a key enzyme for transamination in SGA biosynthesis. The disruption of PGA4 function by genome editing will be a viable approach for accumulating valuable steroidal saponins in SGA-free potatoes.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::18799b71cbc8e0bf35182c48c4c967a9Test
https://doi.org/10.1111/tpj.15426Test

4

Tandem Mass Spectrum Similarity-Based Network Analysis Using 13C-Labeled and Non-labeled Metabolome Data to Identify the Biosynthetic Pathway of the Blood Pressure-Lowering Asparagus Metabolite Asparaptine A

المؤلفون: Tetsuya Mori, Tomoko Nishizawa, Yutaka Yamada, Kazuki Saito, Takashi Asano, Ryo Nakabayashi, Masanari Kuwabara

المصدر: Journal of Agricultural and Food Chemistry. 69:8571-8577

مصطلحات موضوعية: chemistry.chemical_classification, Arginine, biology, Chemistry, Metabolite, Lysine, General Chemistry, biology.organism_classification, chemistry.chemical_compound, Enzyme, Metabolomics, Biosynthesis, Biochemistry, Valine, Metabolome, Asparagusic acid, Asparagus, General Agricultural and Biological Sciences, Histidine

الوصف: Asparaptine, a conjugate of arginine and asparagusic acid, was found in asparagus (Asparagus officinalis) as a naturally occurring inhibitor of angiotensin-converting enzyme (ACE) in vitro. The biosynthetic pathway to asparaptine is largely unknown; however, it is suggested that asparagusic acid may be biosynthesized from valine. To determine which metabolites are involved in the asparaptine biosynthetic pathway, we performed tandem mass spectrometry similarity-based metabolome network analysis using 13C labeled and non-labeled valine-fed asparagus calluses. We determined that valine is used as a starting material, S(2-carboxy-n-propyl)-cysteine as an intermediate, and two new metabolites as asparaptine analogs, lysine- and histidine-type conjugates, are involved in the pathway. Asparaptine was therefore renamed asparaptine A (arginine type), and the two analogs were named asparaptines B (lysine type) and C (histidine type). Oral feeding of asparaptine A to a hypertensive mouse species showed that this metabolite lowers both blood pressure and heart rate within two hours and both of which were back to normal two days later. These results suggest that asparaptine A may not only have effects as an ACE inhibitor, but also has β-antagonistic effects, which are well-known to be preventive for cardiovascular diseases.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::1bd9bb974965a94a3181015530fa04b0Test
https://doi.org/10.1021/acs.jafc.1c01183Test

5

Mass spectrometry-based metabolomics: a guide for annotation, quantification and best reporting practices

المصدر: Nat Methods
Nature Methods, 18(7), 747-756
Nature Methods 18 (2021) 7
Nature Methods

الوصف: Mass spectrometry-based metabolomics approaches can enable detection and quantification of many thousands of metabolite features simultaneously. However, compound identification and reliable quantification are greatly complicated owing to the chemical complexity and dynamic range of the metabolome. Simultaneous quantification of many metabolites within complex mixtures can additionally be complicated by ion suppression, fragmentation and the presence of isomers. Here we present guidelines covering sample preparation, replication and randomization, quantification, recovery and recombination, ion suppression and peak misidentification, as a means to enable high-quality reporting of liquid chromatography– and gas chromatography–mass spectrometry-based metabolomics-derived data.

وصف الملف: application/octet-stream; application/pdf

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::1888e135df2ac1adedc0762dde81fc5cTest
https://doi.org/10.1038/s41592-021-01197-1Test

6

Food Lipidomics for 155 Agricultural Plant Products

المؤلفون: Mikiko Takahashi, Hiroshi Tsugawa, Yozo Okazaki, Kazuki Saito, Ryo Nakabayashi, Yutaka Yamada, Yuki Matsuzawa, Kouji Takano, Yasuhiro Higashi

المصدر: Journal of Agricultural and Food Chemistry. 69:8981-8990

الوصف: Lipids exhibit functional bioactivities based on their polar and acyl chain properties; humans obtain lipids from dietary plant product intake. Therefore, the identification of different molecular species facilitates the evaluation of biological functions and nutrition levels and new phenotype-modulating lipid structures. As a rapid screening strategy, we performed untargeted lipidomics for 155 agricultural products in 58 species from 23 plant families, wherein product-specific lipid diversities were shown using computational mass spectrometry. We characterized 716 lipid species, for which the profiles revealed the National Center for Biotechnology Information-established organismal classification and unique plant tissue metabotypes. Moreover, we annotated unreported subclasses in plant lipidology; e.g., triacylglycerol estolide (TG-EST) was detected in rice seeds (Oryza sativa) and several plant species. TG-EST is known as the precursor molecule producing the fatty acid ester of hydroxy fatty acid, which lowers ambient glycemia and improves glucose tolerance. Hence, our method can identify agricultural plant products containing valuable lipid ingredients.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::f94e97d418cac23e1a6866255bae2dd6Test
https://doi.org/10.1021/acs.jafc.0c07356Test

7

Metabolite profiling of the hyphal exudates of Rhizophagus clarus and Rhizophagus irregularis under phosphorus deficiency

المؤلفون: Tantriani, Nozomi Inamura, Keitaro Tawaraya, Nuri Luthfiana, Takumi Sato, Weiguo Chen, Akira Oikawa, Kazuki Saito

المصدر: Mycorrhiza. 31:403-412

الوصف: Arbuscular mycorrhizal (AM) fungal extraradical hyphae exude their metabolites into the soil. Root exudate metabolites are affected by plant species and P status. However, the effect of P status on AM hyphal exudate metabolites has been unknown. This study aimed to examine hyphal exudate metabolite composition of two AM fungal species and their response to P deficiency through metabolite profiling. Rhizophagus clarus and R. irregularis were grown in a two-compartment in vitro culture system of Linum usitatissimum roots on solid modified Strullu-Romand medium in combination with two P levels (3 µM (P3) and 30 µM (P30)). Hyphal exudates were collected from the hyphal compartment at 118 days after inoculation (DAI). The metabolite composition of the hyphal exudates was determined by capillary electrophoresis/time-of-flight mass spectrometry, resulting in the identification of a total of 141 metabolites at 118 DAI. In the hyphal exudates of R. clarus, the concentrations of 18 metabolites, including sugars, amino acids, and organic acids, were significantly higher (p

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::6bed8898d1a0b89336e93883d9ae03c4Test
https://doi.org/10.1007/s00572-020-01016-zTest

8

Metabolomics and complementary techniques to investigate the plant phytochemical cosmos

المؤلفون: Hiroshi Tsugawa, Amit Rai, Kazuki Saito, Ryo Nakabayashi

المصدر: Natural Product Reports. 38:1729-1759

الوصف: Covering: up to 2021Plants and their associated microbial communities are known to produce millions of metabolites, a majority of which are still not characterized and are speculated to possess novel bioactive properties. In addition to their role in plant physiology, these metabolites are also relevant as existing and next-generation medicine candidates. Elucidation of the plant metabolite diversity is thus valuable for the successful exploitation of natural resources for humankind. Herein, we present a comprehensive review on recent metabolomics approaches to illuminate molecular networks in plants, including chemical isolation and enzymatic production as well as the modern metabolomics approaches such as stable isotope labeling, ultrahigh-resolution mass spectrometry, metabolome imaging (spatial metabolomics), single-cell analysis, cheminformatics, and computational mass spectrometry. Mass spectrometry-based strategies to characterize plant metabolomes through metabolite identification and annotation are described in detail. We also highlight the use of phytochemical genomics to mine genes associated with specialized metabolites' biosynthesis. Understanding the metabolic diversity through biotechnological advances is fundamental to elucidate the functions of the plant-derived specialized metabolome.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::fb3b7f9b17aca33be1f589decdd08fbaTest
https://doi.org/10.1039/d1np00014dTest

9

Seed-coat protective neolignans are produced by the dirigent protein AtDP1 and the laccase AtLAC5 in Arabidopsis

المؤلفون: Satoko Sugawara, Fumio Matsuda, Masaomi Yamamura, Yuki Tobimatsu, Tetsuya Mori, Keiko Yonekura-Sakakibara, Eiichiro Ono, Ryo Nakabayashi, Toshiaki Umezawa, Kazuki Saito

المصدر: Plant Cell

الوصف: Lignans/neolignans are generally synthesized from coniferyl alcohol (CA) in the cinnamate/monolignol pathway by oxidation to generate the corresponding radicals with subsequent stereoselective dimerization aided by dirigent proteins (DIRs). Genes encoding oxidases and DIRs for neolignan biosynthesis have not been identified previously. In Arabidopsis thaliana, the DIR AtDP1/AtDIR12 plays an essential role in the 8-O-4′ coupling in neolignan biosynthesis by unequivocal structural determination of the compound missing in the atdp1 mutant as a sinapoylcholine (SC)-conjugated neolignan, erythro-3-{4-[2-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-1-hydroxymethylethoxy]-3, 5-dimethoxyphenyl}acryloylcholine. Phylogenetic analyses showed that AtDP1/AtDIR12 belongs to the DIR-a subfamily composed of DIRs for 8-8′ coupling of monolignol radicals. AtDP1/AtDIR12 is specifically expressed in outer integument 1 cells in developing seeds. As a putative oxidase for neolignan biosynthesis, we focused on AtLAC5, a laccase gene coexpressed with AtDP1/AtDIR12. In lac5 mutants, the abundance of feruloylcholine (FC)-conjugated neolignans decreased to a level comparable to those in the atdp1 mutant. In addition, SC/FC-conjugated neolignans were missing in the seeds of mutants defective in SCT/SCPL19, an enzyme that synthesizes SC. These results strongly suggest that AtDP1/AtDIR12 and AtLAC5 are involved in neolignan biosynthesis via SC/FC. A tetrazolium penetration assay showed that seed coat permeability increased in atdp1 mutants, suggesting a protective role of neolignans in A. thaliana seeds.
種子を保護するネオリグナンの生合成機構を解明 --新たな薬効成分の創出に期待--. 京都大学プレスリリース. 2020-12-03.

وصف الملف: application/pdf

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::72b2ef265c5dcde7b4e7e6e0b751a09bTest
http://hdl.handle.net/2433/261032Test

10

A cellulose synthase-derived enzyme catalyses 3-O-glucuronosylation in saponin biosynthesis

المؤلفون: Yukiko Fujisawa, Kazuki Saito, Hikaru Seki, Soo Yeon Chung, Susumu Hiraga, Masao Ishimoto, Yuhta Nomura, Toshiya Muranaka, Yoshikazu Shimoda

المصدر: Nature Communications, Vol 11, Iss 1, Pp 1-11 (2020)
Nature Communications

مصطلحات موضوعية: 0106 biological sciences, 0301 basic medicine, Glycosylation, Saponin, General Physics and Astronomy, Molecular engineering in plants, Endoplasmic Reticulum, 01 natural sciences, Substrate Specificity, chemistry.chemical_compound, Glucuronic Acid, Gene Expression Regulation, Plant, Glycyrrhiza uralensis, lcsh:Science, Phylogeny, chemistry.chemical_classification, Likelihood Functions, Multidisciplinary, biology, musculoskeletal system, Biochemistry, Glucosyltransferases, Science, Lotus japonicus, Saccharomyces cerevisiae, complex mixtures, General Biochemistry, Genetics and Molecular Biology, Article, 03 medical and health sciences, Biosynthesis, Transferases, Glycosyltransferase, parasitic diseases, Glycyrrhizin, fungi, General Chemistry, Saponins, biology.organism_classification, Glycyrrhizic Acid, Yeast, Triterpenes, Biosynthetic Pathways, carbohydrates (lipids), 030104 developmental biology, chemistry, biology.protein, Biocatalysis, Lotus, Uridine Diphosphate Glucuronic Acid, lcsh:Q, Soybeans, Secondary metabolism, Metabolic engineering, 010606 plant biology & botany

الوصف: Triterpenoid saponins are specialised metabolites distributed widely in the plant kingdom that consist of one or more sugar moieties attached to triterpenoid aglycones. Despite the widely accepted view that glycosylation is catalysed by UDP-dependent glycosyltransferase (UGT), the UGT which catalyses the transfer of the conserved glucuronic acid moiety at the C-3 position of glycyrrhizin and various soyasaponins has not been determined. Here, we report that a cellulose synthase superfamily-derived glycosyltransferase (CSyGT) catalyses 3-O-glucuronosylation of triterpenoid aglycones. Gene co-expression analyses of three legume species (Glycyrrhiza uralensis, Glycine max, and Lotus japonicus) reveal the involvement of CSyGTs in saponin biosynthesis, and we characterise CSyGTs in vivo using Saccharomyces cerevisiae. CSyGT mutants of L. japonicus do not accumulate soyasaponin, but the ectopic expression of endoplasmic reticulum membrane–localised CSyGTs in a L. japonicus mutant background successfully complement soyasaponin biosynthesis. Finally, we produced glycyrrhizin de novo in yeast, paving the way for sustainable production of high-value saponins.
Saponins such as glycyrrhizin, a natural sweetener found in licorice root, are a class of triterpenoids synthesized that are characterized by a glucoronic acid moiety at the C-3 position. Here the authors show that saponin glucuronosylation is catalyzed by cellulose-synthase like enzymes and reconstitute glycyrrhizin synthesisin yeast.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::a02ab1e325d29b6a97f7fa7b620ffb67Test
https://doaj.org/article/50da0353228b47459b770b0681f56728Test

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