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Hiroshi Matsumoto - One of the best experts on this subject based on the ideXlab platform.
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Isolation of ambiguine D isonitrile from Hapalosiphon sp. and characterization of its phytotoxic activity
Plant Growth Regulation, 2012Co-Authors: Intira Koodkaew, Yukari Sunohara, Shigeru Matsuyama, Hiroshi MatsumotoAbstract:Cyanobacterium Hapalosiphon sp. contains phytotoxic substances. Fractionation of Hapalosiphon sp. crude extract guided by lettuce seedlings bioassay revealed that multiple fractions contained differential plant growth suppression activity. From the most active fraction inhibiting the growth of lettuce, ambiguine D isonitrile was isolated. A physiological study with ambiguine D isonitrile showed that it effectively inhibited mitosis, which resulted in the suppression of root growth. Ambiguine D isonitrile caused increased reactive oxygen species (ROS) generation and was associated with observed lipid peroxidation and cell death. These oxidative processes probably play a key role in the phytotoxic action of ambiguine D isonitrile in plants.
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Phytotoxic action mechanism of hapalocyclamide in lettuce seedlings.
Plant Physiology and Biochemistry, 2012Co-Authors: Intira Koodkaew, Yukari Sunohara, Shigeru Matsuyama, Hiroshi MatsumotoAbstract:Abstract Hapalocyclamide ( cyclo -thiazole- l -alanine-oxazole- d -alanine- d -thiazoline- d -phenylalanine), a hexapeptide phytotoxic compound, was isolated from the terrestrial cyanobacterium Hapalosiphon sp. The phytotoxic action of the compound was investigated in lettuce ( Lactuca sativa L. cv. Great Lakes no. 366) by determining its effects on several physiological processes. Hapalocyclamide effectively inhibited mitosis process in root tips, which resulted in the suppression of primary root growth of lettuce. The compound also induced overproduction of reactive oxygen species (ROS) and loss of cell viability in root cells. Moreover, hapalocyclamide-induced lipid peroxidation in both roots and shoots. Therefore, the primary action of hapalocyclamide to suppress lettuce growth might be caused by ROS overproduction, which induces major oxidative damage to membrane lipids, resulting in cell death and growth inhibition.
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hapalocyclamide a novel phytotoxic hexapeptide of the cyanobacterium Hapalosiphon sp
Tetrahedron Letters, 2012Co-Authors: Intira Koodkaew, Yukari Sunohara, Shigeru Matsuyama, Hiroshi MatsumotoAbstract:Abstract Hapalocyclamide, a novel oxazole-, thiazole- and thiazoline-containing cyclic hexapeptide, was isolated from the terrestrial cyanobacterium Hapalosiphon sp., and which showed phytotoxic activity on lettuce seedling growth. The gross structure of hapalocyclamide was established from spectroscopic data and chemical degradation. The absolute stereochemistry was determined by Marfey’s analysis. Hapalocyclamide was established as cyclo-thiazole- l -alanine-oxazole- d -alanine- d -thiazoline- d -phenylalanine.
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characterization of reactive oxygen species involved oxidative damage in Hapalosiphon species crude extract treated wheat and onion roots
Weed Biology and Management, 2007Co-Authors: Nuttha Sanevas, Yukari Sunohara, Hiroshi MatsumotoAbstract:Crude extract-induced oxidative damage using the cyanobacterium, Hapalosiphon sp., was investigated in wheat seedlings (Triticum aestivum L. cv. Norin 61) and onion seedlings (Allium cepa L. cv. Raputa II). The analysis of root cell viability or cell death using Evans blue uptake showed that the root-tip cells of wheat and onion lost viability after 24 h and 48 h treatment with 3 g dry weight (DW) L−1 of the crude extract, respectively. Lipid peroxidation was induced in the roots of both species and the shoots of onion, whereas no increase in lipid peroxide formation was observed in the wheat shoots. In onion, the degree of random DNA fragmentation increased with the increasing concentration of the extract and laddering of the DNA was observed with 6 g DW L−1 of the extract, but no apparent DNA ladder formation occurred in the wheat. Pretreatment for 1 h with the NADPH oxidase inhibitors, diphenyleneidonium or imidazole, reduced the crude extract-induced root cell death in both species. From the results, we suggest that the Hapalosiphon sp. crude extract might enhance reactive oxygen species (ROS) production, which causes membrane lipid damage and fragmentation of the DNA of plant cells, resulting in cell death and growth inhibition. The crude extract-mediated phytotoxic damage might be caused by ROS, triggered by NADPH oxidase.
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Characterization of reactive oxygen species‐involved oxidative damage in Hapalosiphon species crude extract‐treated wheat and onion roots
Weed Biology and Management, 2007Co-Authors: Nuttha Sanevas, Yukari Sunohara, Hiroshi MatsumotoAbstract:Crude extract-induced oxidative damage using the cyanobacterium, Hapalosiphon sp., was investigated in wheat seedlings (Triticum aestivum L. cv. Norin 61) and onion seedlings (Allium cepa L. cv. Raputa II). The analysis of root cell viability or cell death using Evans blue uptake showed that the root-tip cells of wheat and onion lost viability after 24 h and 48 h treatment with 3 g dry weight (DW) L−1 of the crude extract, respectively. Lipid peroxidation was induced in the roots of both species and the shoots of onion, whereas no increase in lipid peroxide formation was observed in the wheat shoots. In onion, the degree of random DNA fragmentation increased with the increasing concentration of the extract and laddering of the DNA was observed with 6 g DW L−1 of the extract, but no apparent DNA ladder formation occurred in the wheat. Pretreatment for 1 h with the NADPH oxidase inhibitors, diphenyleneidonium or imidazole, reduced the crude extract-induced root cell death in both species. From the results, we suggest that the Hapalosiphon sp. crude extract might enhance reactive oxygen species (ROS) production, which causes membrane lipid damage and fragmentation of the DNA of plant cells, resulting in cell death and growth inhibition. The crude extract-mediated phytotoxic damage might be caused by ROS, triggered by NADPH oxidase.
Richard P Sheridan - One of the best experts on this subject based on the ideXlab platform.
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nitrogenase activity by Hapalosiphon flexuosus associated with sphagnum erythrocalyx mats in the cloud forest on the volcano la soufriere guadeloupe french west indies
Biotropica, 1991Co-Authors: Richard P SheridanAbstract:Acid mats of Sphagnum erythrocalyx Hampe. growing on the dome of the tropical volcano La Soufriere, Guadeloupe, French West Indies, support associated populations of the nitrogen-fixing cyanobacterium Hapalosiphon flexuosus Borzi. The acetylene reduction technique was employed to measure nitrogenase activity. The mean rate of C2H4 production in situ by entire plants with the associated cyanobacterium was 19.1 nmol C2H4 gdwh-I (range 0.20101) with a nitrogenase activity for the uppermost green tips 4.5 times greater than that measured for the basal portions. The highest rates for C2H2 reduction were recorded for plants damaged by high winds and for those plants established within vegetation zones recovering from severe damage resulting from the 1976-1977 phreatic eruption of this volcano. The estimated rate of the annual contribution of nitrogen by nitrogen fixation is 4.02 kg N-ha-l year-'. THIS PAPER REPORTS THE RESULTS OF A STUDY OF NIT-ROGEN FIXATION by epiand endophytic cyanobacteria on Sphagnum to the nitrogen economy of the cloud forest orobiome on the tropical volcano La Soufriere. Also discussed is the relationship between the rates of acetylene reduction and the degree of habitat damage following the 1976-1977 eruption of the volcano La Soufriere. La Soufriere (alt. 1467 m), a recently active volcano located on the island of Guadeloupe in the French West Indies (16?40'N, 60?10'E), supports an orobiome (1000-1467 m) termed savane d'altitude (Stehle 1935, 1979), tropical doud forest (Howard 1970), or cloud-shroud ecosystem (sensu Odum 1970). The prevailing doud cover is only occasionally broken by periods of high insolation subjecting the flora, which is adapted to the prevailing low temperatures and insolation values, to unfiltered sunlight and high temperatures (Fritz-Sheridan & Coxson 1988a). Tropical cloud forests, characterized by persistent cloud cover, promote colonization by poikilohydric plants such as mosses and lichens (Grubb 1977, La Bastille & Pool 1978, Weaver et al. 1973, Weaver et al. 1986). The prevailing high moisture and low temperatures reduce the mineralization rate (Grubb 1971, 1977), and mineral loss is accelerated by high rainfall on the steep slopes of La Soufriere, mnaking nitrogen input by fixation a potentially important part of the mineral cycle. I Received 30 January 1990, revision accepted 28 September 1990. 2 Formerly Fritz-Sheridan. The eruptions in 1976 and 1977 disturbed the pre-eruption flora by fumigation with hydrogen sulfide gas and the deposition of ash and boulders, effectively dividing the dome into four distinct posteruption vegetation zones (Howard 1962, Howard et al. 1980, Sastre et al. 1983). This cloud forest supports a diverse group of nitrogen-fixing cyanobacteria, and primary succession in lahar flows on the east flank is by the nitrogen-fixing lichens Dictyonema glabratum and Stereocaulon virgatum (Coxson 1987; Fritz-Sheridan 1987, 1988; Fritz-Sheridan & Coxson 1988a, b; Fritz-Sheridan & Portecop 1987). The occurrence and nitrogenase activities of nitrogen-fixing microepiphytes on dominant species of vascular plants involved in posteruption revegetation (e.g., Clusia mangle, Norantia spiciflora, Tibouchina ornata) have been described by Fritz-Sheridan & Portecop (1987). Sastre et al. (1983) divided the dome of La Soufriere into quadrats and 30 percent of these were occupied by Sphagnum erythrocalyx Hampe.
Janelle R Thompson - One of the best experts on this subject based on the ideXlab platform.
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insights from the draft genome of the subsection v stigonematales cyanobacterium Hapalosiphon sp strain mrb220 associated with 2 mib production
Standards in Genomic Sciences, 2016Co-Authors: Shu Harn Te, Janelle R ThompsonAbstract:A non-axenic unialgal culture containing a Subsection V (Stigonematales) cyanobacterium, Hapalosiphon strain MRB 220, was obtained from a benthic freshwater algal mat through multiple transfers following growth in sterile media. Physiological characterization demonstrated the culture was capable of nitrogen-fixation and production of the off flavor compound 2-methylisoborneol (2-MIB). Total DNA isolated from this culture was sequenced using Illumina HiSeq and de novo assembled into contigs. The genome of MRB 220 was separated from co-occurring heterotrophic bacteria using sequence homology and compositional approaches, and its purity was confirmed based on best BLAST hit classification and principle component analysis of the tetranucleotide frequencies of fragmented contigs. The genome of ~7.4 Mbp contains 6,345 protein coding genes with 4,320 of these having functional prediction including predicted pathways for biosynthesis of the secondary metabolite welwitindolinone. Analyses of 16S rRNA gene and whole genome sequence average nucleotide identity indicated close relatedness of MRB 220 to the genera Hapalosiphon and Fischerella within the order Stigonematales. Microscopic examination showed that MRB 220 formed heterocystous branched filaments, thereby supporting identification of strain MRB 220 as a morphospecies of Hapalosiphon. Availability of the draft genome of Hapalosiphon strain MRB 220 enables future work to elucidate the pathway and dynamics for biosynthesis of 2-MIB and other secondary metabolites and understand the ecology and physiology of Stigonematales cyanobacteria in tropical freshwaters.
Yukari Sunohara - One of the best experts on this subject based on the ideXlab platform.
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Isolation of ambiguine D isonitrile from Hapalosiphon sp. and characterization of its phytotoxic activity
Plant Growth Regulation, 2012Co-Authors: Intira Koodkaew, Yukari Sunohara, Shigeru Matsuyama, Hiroshi MatsumotoAbstract:Cyanobacterium Hapalosiphon sp. contains phytotoxic substances. Fractionation of Hapalosiphon sp. crude extract guided by lettuce seedlings bioassay revealed that multiple fractions contained differential plant growth suppression activity. From the most active fraction inhibiting the growth of lettuce, ambiguine D isonitrile was isolated. A physiological study with ambiguine D isonitrile showed that it effectively inhibited mitosis, which resulted in the suppression of root growth. Ambiguine D isonitrile caused increased reactive oxygen species (ROS) generation and was associated with observed lipid peroxidation and cell death. These oxidative processes probably play a key role in the phytotoxic action of ambiguine D isonitrile in plants.
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Phytotoxic action mechanism of hapalocyclamide in lettuce seedlings.
Plant Physiology and Biochemistry, 2012Co-Authors: Intira Koodkaew, Yukari Sunohara, Shigeru Matsuyama, Hiroshi MatsumotoAbstract:Abstract Hapalocyclamide ( cyclo -thiazole- l -alanine-oxazole- d -alanine- d -thiazoline- d -phenylalanine), a hexapeptide phytotoxic compound, was isolated from the terrestrial cyanobacterium Hapalosiphon sp. The phytotoxic action of the compound was investigated in lettuce ( Lactuca sativa L. cv. Great Lakes no. 366) by determining its effects on several physiological processes. Hapalocyclamide effectively inhibited mitosis process in root tips, which resulted in the suppression of primary root growth of lettuce. The compound also induced overproduction of reactive oxygen species (ROS) and loss of cell viability in root cells. Moreover, hapalocyclamide-induced lipid peroxidation in both roots and shoots. Therefore, the primary action of hapalocyclamide to suppress lettuce growth might be caused by ROS overproduction, which induces major oxidative damage to membrane lipids, resulting in cell death and growth inhibition.
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hapalocyclamide a novel phytotoxic hexapeptide of the cyanobacterium Hapalosiphon sp
Tetrahedron Letters, 2012Co-Authors: Intira Koodkaew, Yukari Sunohara, Shigeru Matsuyama, Hiroshi MatsumotoAbstract:Abstract Hapalocyclamide, a novel oxazole-, thiazole- and thiazoline-containing cyclic hexapeptide, was isolated from the terrestrial cyanobacterium Hapalosiphon sp., and which showed phytotoxic activity on lettuce seedling growth. The gross structure of hapalocyclamide was established from spectroscopic data and chemical degradation. The absolute stereochemistry was determined by Marfey’s analysis. Hapalocyclamide was established as cyclo-thiazole- l -alanine-oxazole- d -alanine- d -thiazoline- d -phenylalanine.
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characterization of reactive oxygen species involved oxidative damage in Hapalosiphon species crude extract treated wheat and onion roots
Weed Biology and Management, 2007Co-Authors: Nuttha Sanevas, Yukari Sunohara, Hiroshi MatsumotoAbstract:Crude extract-induced oxidative damage using the cyanobacterium, Hapalosiphon sp., was investigated in wheat seedlings (Triticum aestivum L. cv. Norin 61) and onion seedlings (Allium cepa L. cv. Raputa II). The analysis of root cell viability or cell death using Evans blue uptake showed that the root-tip cells of wheat and onion lost viability after 24 h and 48 h treatment with 3 g dry weight (DW) L−1 of the crude extract, respectively. Lipid peroxidation was induced in the roots of both species and the shoots of onion, whereas no increase in lipid peroxide formation was observed in the wheat shoots. In onion, the degree of random DNA fragmentation increased with the increasing concentration of the extract and laddering of the DNA was observed with 6 g DW L−1 of the extract, but no apparent DNA ladder formation occurred in the wheat. Pretreatment for 1 h with the NADPH oxidase inhibitors, diphenyleneidonium or imidazole, reduced the crude extract-induced root cell death in both species. From the results, we suggest that the Hapalosiphon sp. crude extract might enhance reactive oxygen species (ROS) production, which causes membrane lipid damage and fragmentation of the DNA of plant cells, resulting in cell death and growth inhibition. The crude extract-mediated phytotoxic damage might be caused by ROS, triggered by NADPH oxidase.
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Characterization of reactive oxygen species‐involved oxidative damage in Hapalosiphon species crude extract‐treated wheat and onion roots
Weed Biology and Management, 2007Co-Authors: Nuttha Sanevas, Yukari Sunohara, Hiroshi MatsumotoAbstract:Crude extract-induced oxidative damage using the cyanobacterium, Hapalosiphon sp., was investigated in wheat seedlings (Triticum aestivum L. cv. Norin 61) and onion seedlings (Allium cepa L. cv. Raputa II). The analysis of root cell viability or cell death using Evans blue uptake showed that the root-tip cells of wheat and onion lost viability after 24 h and 48 h treatment with 3 g dry weight (DW) L−1 of the crude extract, respectively. Lipid peroxidation was induced in the roots of both species and the shoots of onion, whereas no increase in lipid peroxide formation was observed in the wheat shoots. In onion, the degree of random DNA fragmentation increased with the increasing concentration of the extract and laddering of the DNA was observed with 6 g DW L−1 of the extract, but no apparent DNA ladder formation occurred in the wheat. Pretreatment for 1 h with the NADPH oxidase inhibitors, diphenyleneidonium or imidazole, reduced the crude extract-induced root cell death in both species. From the results, we suggest that the Hapalosiphon sp. crude extract might enhance reactive oxygen species (ROS) production, which causes membrane lipid damage and fragmentation of the DNA of plant cells, resulting in cell death and growth inhibition. The crude extract-mediated phytotoxic damage might be caused by ROS, triggered by NADPH oxidase.
Daniel H Kwak - One of the best experts on this subject based on the ideXlab platform.
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MS Thesis (ETD) Dan Kwak
2015Co-Authors: Daniel H KwakAbstract:Microbial secondary metabolites are physiologically significant, exhibiting auxiliary functions for the producer and as scaffolds in the developments of new medicines. Advancements in genome sequencing technologies have enabled researchers to access unprecedented amounts of genomic data that can be used to discover the enzymatic machinery necessary to discover novel and biologically-active molecules. This approach has been termed “genome mining.” In both of the investigations presented herein, genome mining was utilized to discover and characterize biosynthetic pathways of novel molecules. The findings in one study utilize this approach to discover a small molecule virulence factor from the opportunistic human pathogen Acinetobacter baumannii. This virulence factor has been found to be associated with a number of clinically significant phenotypes, and these findings suggest that this can be a target in the developments of next generation antibiotics. In another study, this approach was implemented to discover and characterize the biosynthetic pathway of anticancer compound hapalosin from the cyanobacterial species Hapalosiphon welwitschii. Cloning and expression of this biosynthetic pathway in the surrogate host Escherichia coli enabled its genetic characterization as well as the generation of a small combinatorial library consisting of analogs incorporating natural and unnatural substrates. Collectively, these investigations demonstrate the utility of genome mining to characterize novel molecules important in pathogenesis or in the biosynthesis of clinically-significant compounds.
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identification and characterization of a welwitindolinone alkaloid biosynthetic gene cluster in the stigonematalean cyanobacterium Hapalosiphon welwitschii
ChemBioChem, 2014Co-Authors: Matthew L Hillwig, Heather A Fuhrman, Kuljira Ittiamornkul, Tyler J Sevco, Daniel H KwakAbstract:Welwitindolinones (Figure 1A) are a unique family of indole monoterpene alkaloids that were originally isolated from true-branching heterocystous filamentous cyanobacterium Hapalosiphon welwitschii with a broad range of biological activities.[1] In particular, (N-methyl)welwitindolinones B and C (1-3) are dual functional antitumor agents that exhibit antimitotic activity with multidrug resistance (MDR) reversal properties.[2] Except welwitindolinone A (4), all welwitindolinones isolated to date are 3,4-disubstituted oxindoles with a signature bicyclo[4.3.1]decane core motif,[1, 3] which has captivated considerable interest from the synthetic chemistry community worldwide that resulted in several total chemical syntheses of this family of molecules.[4]
