Steady-state kinetics of substrate binding and iron release in tomato ACC oxidase.

PubMed

Thrower, J S; Blalock, R; Klinman, J P

2001-08-14

1-Aminocyclopropane-1-carboxylate oxidase (ACC oxidase) catalyzes the last step in the biosynthetic pathway of the plant hormone, ethylene. This unusual reaction results in the oxidative ring cleavage of 1-aminocyclopropane carboxylate (ACC) into ethylene, cyanide, and CO2 and requires ferrous ion, ascorbate, and molecular oxygen for catalysis. A new purification procedure and assay method have been developed for tomato ACC oxidase that result in greatly increased enzymatic activity. This method allowed us to determine the rate of iron release from the enzyme and the effect of the activator, CO2, on this rate. Initial velocity studies support an ordered kinetic mechanism where ACC binds first followed by O2; ascorbate can bind after O2 or possibly before ACC. This kinetic mechanism differs from one recently proposed for the ACC oxidase from avocado.

Characterization and expression analysis of a banana gene encoding 1-aminocyclopropane-1-carboxylate oxidase.

PubMed

Huang, P L; Do, Y Y; Huang, F C; Thay, T S; Chang, T W

1997-04-01

A cDNA encoding the banana 1-aminocyclopropane-1-carboxylate (ACC) oxidase has previously been isolated from a cDNA library that was constructed by extracting poly(A)+ RNA from peels of ripening banana. This cDNA, designated as pMAO2, has 1,199 bp and contains an open reading frame of 318 amino acids. In order to identify ripening-related promoters of the banana ACC oxidase gene, pMAO2 was used as a probe to screen a banana genomic library constructed in the lambda EMBL3 vector. The banana ACC oxidase MAO2 gene has four exons and three introns, with all of the boundaries between these introns and exons sharing a consensus dinucleotide sequence of GT-AG. The expression of MAO2 gene in banana begins after the onset of ripening (stage 2) and continuous into later stages of the ripening process. The accumulation of MAO2 mRNA can be induced by 1 microliter/l exogenous ethylene, and it reached steady state level when 100 microliters/l exogenous ethylene was present.

Cloning of a cDNA encoding 1-aminocyclopropane-1-carboxylate synthase and expression of its mRNA in ripening apple fruit.

PubMed

Dong, J G; Kim, W T; Yip, W K; Thompson, G A; Li, L; Bennett, A B; Yang, S F

1991-08-01

1-Aminocyclopropane-1-carboxylate (ACC) synthase (EC 4.4.1.14) purified from apple (Malus sylvestris Mill.) fruit was subjected to trypsin digestion. Following separation by reversed-phase high-pressure liquid chromatography, ten tryptic peptides were sequenced. Based on the sequences of three tryptic peptides, three sets of mixed oligonucleotide probes were synthesized and used to screen a plasmid cDNA library prepared from poly(A)(+) RNA of ripe apple fruit. A 1.5-kb (kilobase) cDNA clone which hybridized to all three probes were isolated. The clone contained an open reading frame of 1214 base pairs (bp) encoding a sequence of 404 amino acids. While the polyadenine tail at the 3'-end was intact, it lacked a portion of sequence at the 5'-end. Using the RNA-based polymerase chain reaction, an additional sequence of 148 bp was obtained at the 5'-end. Thus, 1362 bp were sequenced and they encode 454 amino acids. The deduced amino-acid sequence contained peptide sequences corresponding to all ten tryptic fragments, confirming the identity of the cDNA clone. Comparison of the deduced amino-acid sequence between ACC synthase from apple fruit and those from tomato (Lycopersicon esculentum Mill.) and winter squash (Cucurbita maxima Duch.) fruits demonstrated the presence of seven highly conserved regions, including the previously identified region for the active site. The size of the translation product of ACC-synthase mRNA was similar to that of the mature protein on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), indicating that apple ACC-synthase undergoes only minor, if any, post-translational proteolytic processing. Analysis of ACC-synthase mRNA by in-vitro translation-immunoprecipitation, and by Northern blotting indicates that the ACC-synthase mRNA was undetectable in unripe fruit, but was accumulated massively during the ripening proccess. These data demonstrate that the expression of the ACC-synthase gene is developmentally regulated.

Ethylene and 1-Aminocyclopropane-1-carboxylate (ACC) in Plant–Bacterial Interactions

PubMed Central

Nascimento, Francisco X.; Rossi, Márcio J.; Glick, Bernard R.

2018-01-01

Ethylene and its precursor 1-aminocyclopropane-1-carboxylate (ACC) actively participate in plant developmental, defense and symbiotic programs. In this sense, ethylene and ACC play a central role in the regulation of bacterial colonization (rhizospheric, endophytic, and phyllospheric) by the modulation of plant immune responses and symbiotic programs, as well as by modulating several developmental processes, such as root elongation. Plant-associated bacterial communities impact plant growth and development, both negatively (pathogens) and positively (plant-growth promoting and symbiotic bacteria). Some members of the plant-associated bacterial community possess the ability to modulate plant ACC and ethylene levels and, subsequently, modify plant defense responses, symbiotic programs and overall plant development. In this work, we review and discuss the role of ethylene and ACC in several aspects of plant-bacterial interactions. Understanding the impact of ethylene and ACC in both the plant host and its associated bacterial community is key to the development of new strategies aimed at increased plant growth and protection. PMID:29520283

1-Aminocyclopropane-1-carboxylic acid (ACC) deaminase-containing rhizobacteria protect Ocimum sanctum plants during waterlogging stress via reduced ethylene generation.

PubMed

Barnawal, Deepti; Bharti, Nidhi; Maji, Deepamala; Chanotiya, Chandan Singh; Kalra, Alok

2012-09-01

Ocimum sanctum grown as rain-fed crop, is known to be poorly adapted to waterlogged conditions. Many a times the crop suffers extreme damages because of anoxia and excessive ethylene generation due to waterlogging conditions present under heavy rain. The usefulness of 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase-containing plant growth promoting rhizobacteria was investigated under waterlogging stress. The comparison of herb yield and stress induced biochemical changes of waterlogged and non-waterlogged plants with and without ACC deaminase-containing microbiological treatments were monitored in this study. Ten plant growth promoting rhizobacteria strains containing ACC-deaminase were isolated and characterized. Four selected isolates Fd2 (Achromobacter xylosoxidans), Bac5 (Serratia ureilytica), Oci9 (Herbaspirillum seropedicae) and Oci13 (Ochrobactrum rhizosphaerae) had the potential to protect Ocimum plants from flood induced damage under waterlogged glass house conditions. Pot experiments were conducted to evaluate the potential of these ACC deaminase-containing selected strains for reducing the yield losses caused by waterlogging conditions. Bacterial treatments protected plants from waterlogging induced detrimental changes like stress ethylene production, reduced chlorophyll concentration, higher lipid peroxidation, proline concentration and reduced foliar nutrient uptake. Fd2 (A. xylosoxidans) induced maximum waterlogging tolerance as treated waterlogged plants recorded maximum growth and herb yield (46.5% higher than uninoculated waterlogged plants) with minimum stress ethylene levels (53% lower ACC concentration as compared to waterlogged plants without bacterial inoculation) whereas under normal non-waterlogged conditions O. rhizosphaerae was most effective in plant growth promotion. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Purification and Characterization of 1-Aminocyclopropane-1-Carboxylate Synthase from Apple Fruits 1

PubMed Central

Yip, Wing-Kin; Dong, Jian-Guo; Yang, Shang Fa

1991-01-01

1-Aminocyclopropane-1-carboxylate (ACC) synthase, a key enzyme in ethylene biosynthesis, was isolated and partially purified from apple (Malus sylvestris Mill.) fruits. Unlike ACC synthase isolated from other sources, apple ACC synthase is associated with the pellet fraction and can be solubilized in active form with Triton X-100. Following five purification steps, the solubilized enzyme was purified over 5000-fold to a specific activity of 100 micromoles per milligram protein per hour, and its purity was estimated to be 20 to 30%. Using this preparation, specific monoclonal antibodies were raised. Monoclonal antibodies against ACC synthase immunoglobulin were coupled to protein-A agarose to make an immunoaffinity column, which effectively purified the enzyme from a relatively crude enzyme preparation (100 units per milligram protein). As with the tomato enzyme, apple ACC synthase was inactivated and radiolabeled by its substrate S-adenosyl-l-methionine. Apple ACC synthase was identified to be a 48-kilodalton protein based on the observation that it was specifically bound to immunoaffinity column and it was specifically radiolabeled by its substrate S-adenosyl-l-methionine. Images Figure 4 Figure 6 PMID:16667960

Rhizosphere bacteria containing 1-aminocyclopropane-1-carboxylate deaminase increase yield of plants grown in drying soil via both local and systemic hormone signalling.

PubMed

Belimov, Andrey A; Dodd, Ian C; Hontzeas, Nikos; Theobald, Julian C; Safronova, Vera I; Davies, William J

2009-01-01

Decreased soil water availability can stimulate production of the plant hormone ethylene and inhibit plant growth. Strategies aimed at decreasing stress ethylene evolution might attenuate its negative effects. An environmentally benign (nonchemical) method of modifying crop ethylene relations - soil inoculation with a natural root-associated bacterium Variovorax paradoxus 5C-2 (containing the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase that degrades the ethylene precursor ACC), was assessed with pea (Pisum sativum) plants grown in drying soil. Inoculation with V. paradoxus 5C-2, but not with a transposome mutant with massively decreased ACC deaminase activity, improved growth, yield and water-use efficiency of droughted peas. Systemic effects of V. paradoxus 5C-2 included an amplified soil drying-induced increase of xylem abscisic acid (ABA) concentration, but an attenuated soil drying-induced increase of xylem ACC concentration. A local bacterial effect was increased nodulation by symbiotic nitrogen-fixing bacteria, which prevented a drought-induced decrease in nodulation and seed nitrogen content. Successfully deploying a single bacterial gene in the rhizosphere increased yield and nutritive value of plants grown in drying soil, via both local and systemic hormone signalling. Such bacteria may provide an easily realized, economic means of sustaining crop yields and using irrigation water more efficiently in dryland agriculture.

A colorimetric assay of 1-aminocyclopropane-1-carboxylate (ACC) based on ninhydrin reaction for rapid screening of bacteria containing ACC deaminase.

PubMed

Li, Z; Chang, S; Lin, L; Li, Y; An, Q

2011-08-01

1-Aminocyclopropane-1-carboxylate (ACC) deaminase activity is an efficient marker for bacteria to promote plant growth by lowering ethylene levels in plants. We aim to develop a method for rapidly screening bacteria containing ACC deaminase, based on a colorimetric ninhydrin assay of ACC. A reliable colorimetric ninhydrin assay was developed to quantify ACC using heat-resistant polypropylene chimney-top 96-well PCR plates, having the wells evenly heated in boiling water, preventing accidental contamination from boiling water and limiting evaporation. With this method to measure bacterial consumption of ACC, 44 ACC-utilizing bacterial isolates were rapidly screened out from 311 bacterial isolates that were able to grow on minimal media containing ACC as the sole nitrogen source. The 44 ACC-utilizing bacterial isolates showed ACC deaminase activities and belonged to the genus Burkholderia, Pseudomonas or Herbaspirillum. Determination of bacterial ACC consumption by the PCR-plate ninhydrin-ACC assay is a rapid and efficient method for screening bacteria containing ACC deaminase from a large number of bacterial isolates. The PCR-plate ninhydrin-ACC assay extends the utility of the ninhydrin reaction and enables a rapid screening of bacteria containing ACC deaminase from large numbers of bacterial isolates. © 2011 The Authors. Letters in Applied Microbiology © 2011 The Society for Applied Microbiology.

Exploitation of agro-climatic environment for selection of 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase producing salt tolerant indigenous plant growth promoting rhizobacteria.

PubMed

Misra, Sankalp; Dixit, Vijay Kant; Khan, Mohammad Haneef; Kumar Mishra, Shashank; Dviwedi, Gyanendra; Yadav, Sumit; Lehri, Alok; Singh Chauhan, Puneet

2017-12-01

A comprehensive survey for 09 agro-climatic zones of Uttar Pradesh, India was conducted to isolate and characterize salt tolerant 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase possessing plant growth promoting (PGP) rhizobacteria for salt stress amelioration in rice. Here, we have isolated 1125 bacteria having the ability to tolerate 1M NaCl and out of those, 560 were screened for utilizing ACC as sole nitrogen source. 560 isolates were subjected for bacteria coated seed germination assay under 100mM salt (NaCl) stress resulting to 77 isolates which were further evaluated for seed germination assay, PGP and abiotic stress tolerance ability in vitro. This evaluation revealed 15 potent rhizobacteria representing each agro-climatic zone and salt stress mitigation in vitro. In particular, the biomass obtained for bacteria coated rice seedlings were corroborated with the performance of isolates exhibiting maximum average indole acetic acid (IAA) production respective to the agro-climatic zone. Surprisingly based on 16S rRNA, much of the propitious isolates belonged to same specific epithet exhibited variedly in their characteristics. Overall, Bacillus spp. was explored as dominant genera in toto with highest distribution in Western Plain zone followed by Central zone. Therefore, this study provides a counter-intuitive perspective of selection of native microflora for their multifarious PGP and abiotic stress tolerance abilities based on the agro-climatic zones to empower the establishment and development of more suitable inoculants for their application in agriculture under local stress environments. Copyright © 2017 Elsevier GmbH. All rights reserved.

Bacteria in combination with fertilizers promote root and shoot growth of maize in saline-sodic soil.

PubMed

Zafar-Ul-Hye, Muhammad; Farooq, Hafiz Muhammad; Hussain, Mubshar

2015-03-01

Salinity is the leading abiotic stress hampering maize ( Zea mays L.) growth throughout the world, especially in Pakistan. During salinity stress, the endogenous ethylene level in plants increases, which retards proper root growth and consequent shoot growth of the plants. However, certain bacteria contain the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase, which converts 1-aminocyclopropane-1-carboxylic acid (an immediate precursor of ethylene biosynthesis in higher plants) into ammonia and α-ketobutyrate instead of ethylene. In the present study, two Pseudomonas bacterial strains containing ACC-deaminase were tested separately and in combinations with mineral fertilizers to determine their potential to minimize/undo the effects of salinity on maize plants grown under saline-sodic field conditions. The data recorded at 30, 50 and 70 days after sowing revealed that both the Pseudomonas bacterial strains improved root and shoot length, root and shoot fresh weight, and root and shoot dry weight up to 34, 43, 35, 71, 55 and 68%, respectively, when applied without chemical fertilizers: these parameter were enhanced up to 108, 95, 100, 131, 100 and 198%, respectively, when the strains were applied along with chemical fertilizers. It can be concluded that ACC-deaminase Pseudomonas bacterial strains applied alone and in conjunction with mineral fertilizers improved the root and shoot growth of maize seedlings grown in saline-sodic soil.

Bacteria in combination with fertilizers promote root and shoot growth of maize in saline-sodic soil

PubMed Central

Zafar-ul-Hye, Muhammad; Farooq, Hafiz Muhammad; Hussain, Mubshar

2015-01-01

Salinity is the leading abiotic stress hampering maize ( Zea mays L.) growth throughout the world, especially in Pakistan. During salinity stress, the endogenous ethylene level in plants increases, which retards proper root growth and consequent shoot growth of the plants. However, certain bacteria contain the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase, which converts 1-aminocyclopropane-1-carboxylic acid (an immediate precursor of ethylene biosynthesis in higher plants) into ammonia and α-ketobutyrate instead of ethylene. In the present study, two Pseudomonas bacterial strains containing ACC-deaminase were tested separately and in combinations with mineral fertilizers to determine their potential to minimize/undo the effects of salinity on maize plants grown under saline-sodic field conditions. The data recorded at 30, 50 and 70 days after sowing revealed that both the Pseudomonas bacterial strains improved root and shoot length, root and shoot fresh weight, and root and shoot dry weight up to 34, 43, 35, 71, 55 and 68%, respectively, when applied without chemical fertilizers: these parameter were enhanced up to 108, 95, 100, 131, 100 and 198%, respectively, when the strains were applied along with chemical fertilizers. It can be concluded that ACC-deaminase Pseudomonas bacterial strains applied alone and in conjunction with mineral fertilizers improved the root and shoot growth of maize seedlings grown in saline-sodic soil. PMID:26221093

Complete Genome Sequence of the Rhizobacterium Pseudomonas trivialis Strain IHBB745 with Multiple Plant Growth-Promoting Activities and Tolerance to Desiccation and Alkalinity

PubMed Central

Swarnkar, Mohit Kumar; Vyas, Pratibha; Rahi, Praveen; Thakur, Rishu; Thakur, Namika; Singh, Anil Kumar

2015-01-01

The complete genome sequence of 6.45 Mb is reported here for Pseudomonas trivialis strain IHBB745 (MTCC 5336), which is an efficient, stress-tolerant, and broad-spectrum plant growth-promoting rhizobacterium. The gene-coding clusters predicted the genes for phosphate solubilization, siderophore production, 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, indole-3-acetic acid (IAA) production, and stress response. PMID:26337878

Assay Methods for ACS Activity and ACS Phosphorylation by MAP Kinases In Vitro and In Vivo.

PubMed

Han, Xiaomin; Li, Guojing; Zhang, Shuqun

2017-01-01

Ethylene, a gaseous phytohormone, has profound effects on plant growth, development, and adaptation to the environment. Ethylene-regulated processes begin with the induction of ethylene biosynthesis. There are two key steps in ethylene biosynthesis. The first is the biosynthesis of 1-aminocyclopropane-1-carboxylic acid (ACC) from S-Adenosyl-Methionine (SAM), a common precursor in many metabolic pathways, which is catalyzed by ACC synthase (ACS). The second is the oxidative cleavage of ACC to form ethylene under the action of ACC oxidase (ACO). ACC biosynthesis is the committing and generally the rate-limiting step in ethylene biosynthesis. As a result, characterizing the cellular ACS activity and understanding its regulation are important. In this chapter, we detail the methods used to measure, (1) the enzymatic activity of both recombinant and native ACS proteins, and (2) the phosphorylation of ACS protein by mitogen-activated protein kinases (MAPKs) in vivo and in vitro.

Complete Genome Sequence of the Rhizobacterium Pseudomonas trivialis Strain IHBB745 with Multiple Plant Growth-Promoting Activities and Tolerance to Desiccation and Alkalinity.

PubMed

Gulati, Arvind; Swarnkar, Mohit Kumar; Vyas, Pratibha; Rahi, Praveen; Thakur, Rishu; Thakur, Namika; Singh, Anil Kumar

2015-09-03

The complete genome sequence of 6.45 Mb is reported here for Pseudomonas trivialis strain IHBB745 (MTCC 5336), which is an efficient, stress-tolerant, and broad-spectrum plant growth-promoting rhizobacterium. The gene-coding clusters predicted the genes for phosphate solubilization, siderophore production, 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, indole-3-acetic acid (IAA) production, and stress response. Copyright © 2015 Gulati et al.

Inactivation of 1-aminocyclopropane-1-carboxylate oxidase involves oxidative modifications.

PubMed

Barlow, J N; Zhang, Z; John, P; Baldwin, J E; Schofield, C J

1997-03-25

1-Aminocyclopropane-1-carboxylate (ACC) oxidase catalyzes the final step in the biosynthesis of the plant signaling molecule ethylene. It is a member of the ferrous iron dependent family of oxidases and dioxygenases and is unusual in that it displays a very short half-life under catalytic conditions, typically less than 20 min, and a requirement for CO2 as an activator. The rates of inactivation of purified, recombinant ACC oxidase from tomato under various combinations of substrates and cofactors were measured. Inactivation was relatively slow in the presence of buffer alone (t1/2 > 1 h), but fast in the presence of ferrous iron and ascorbate (t1/2 approximately 10 min). The rate of iron/ascorbate-mediated inactivation was increased by the addition of ACC, unaffected by the addition of CO2 at saturation (supplied as bicarbonate) but decreased by the addition of catalase or ACC + CO2 at saturation (supplied as bicarbonate). Iron/ascorbate-mediated inactivation was accompanied by partial proteolysis as observed by SDS-PAGE analysis. The fragmentation pattern was altered when ACC was also included, suggesting that ACC can bind to ACC oxidase in the absence of bicarbonate. N-terminal sequencing of fragments resulted in identification of an internal cleavage site which we propose is proximate to active-site bound iron. Thus, ACC oxidase inactivates via relatively slow partial unfolding of the catalytically active conformation, oxidative damage mediated via hydrogen peroxide which is catalase protectable and oxidative damage to the active site which results in partial proteolysis and is not catalase protectable.

Three 1-Aminocyclopropane-1-Carboxylate Synthase Genes Regulated by Primary and Secondary Pollination Signals in Orchid Flowers1

PubMed Central

Bui, Anhthu Q.; Neill, Sharman D. O'

1998-01-01

The temporal and spatial expression patterns of three 1-aminocyclopropane-1-carboxylate (ACC) synthase genes were investigated in pollinated orchid (Phalaenopsis spp.) flowers. Pollination signals initiate a cascade of development events in multiple floral organs, including the induction of ethylene biosynthesis, which coordinates several postpollination developmental responses. The initiation and propagation of ethylene biosynthesis is regulated by the coordinated expression of three distinct ACC synthase genes in orchid flowers. One ACC synthase gene (Phal-ACS1) is regulated by ethylene and participates in amplification and interorgan transmission of the pollination signal, as we have previously described in a related orchid genus. Two additional ACC synthase genes (Phal-ACS2 and Phal-ACS3) are expressed primarily in the stigma and ovary of pollinated orchid flowers. Phal-ACS2 mRNA accumulated in the stigma within 1 h after pollination, whereas Phal-ACS1 mRNA was not detected until 6 h after pollination. Similar to the expression of Phal-ACS2, the Phal-ACS3 gene was expressed within 2 h after pollination in the ovary. Exogenous application of auxin, but not ACC, mimicked pollination by stimulating a rapid increase in ACC synthase activity in the stigma and ovary and inducing Phal-ACS2 and Phal-ACS3 mRNA accumulation in the stigma and ovary, respectively. These results provide the basis for an expanded model of interorgan regulation of three ACC synthase genes that respond to both primary (Phal-ACS2 and Phal-ACS3) and secondary (Phal-ACS1) pollination signals. PMID:9449850

Effect of 1-methylcyclopropene on shelf life, visual quality and nutritional quality of netted melon.

PubMed

Shi, Y; Wang, B L; Shui, D J; Cao, L L; Wang, C; Yang, T; Wang, X Y; Ye, H X

2015-04-01

The effects of 1-methylcyclopropene (1-MCP) on shelf life, fruit visual quality and nutritional quality were investigated. Netted melons were treated with air (control) and 0.6 µl l(-1) 1-MCP at 25 ℃ for 24 h, and then stored at 25 ℃ or 10 ℃ for 10 days. 1-MCP significantly extended the shelf life, inhibited weight loss and delayed firmness decline of melon fruits. Ethylene production was also inhibited and respiration rate was declined. 1-MCP retarded 1-aminocyclopropane-1-carboxylic acid (ACC) increases and inhibited ACC synthase and ACC oxidase activity. Moreover, 1-MCP treatment reduced the decrease in total soluble solids and titratable acidity, as well as the decrease of the content of sugars (sucrose, fructose and glucose). These results indicated that 1-MCP treatment is a good method to extend melon shelf life and maintain fruit quality, and the combination of 1-MCP and low temperature storage resulted in more acceptable fruit quality. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Burst of ethylene upon horizontal placement of tomato seedlings

NASA Technical Reports Server (NTRS)

Harrison, M.; Pickard, B. G.

1984-01-01

Seedlings of Lycopersicon esculentum Mill. cv Rutgers emit a pulse of ethylene during the first 2 to 4 minutes following horizontal placement. Because this burst appears too rapid and brief to be mediated by increase in net activity of 1-aminocyclopropane-1-carboxylic acid synthase, it might result form accelerated transformation of vacuolar 1-aminocyclopropane-1-carboxylic acid to ethylene.

[Isolation, identification and characterization of ACC deaminase-containing endophytic bacteria from halophyte Suaeda salsa].

PubMed

Teng, Songshan; Liu, Yanping; Zhao, Lei

2010-11-01

We Isolated and characterized 1-aminocyclopropane-1-carboxylate (ACC) deaminase-containing endophytic bacteria from halophyte Suaeda salsa to understand the interactions between endophytes and halophyte. ACC deaminase-containing endophytic bacteria were isolated from root, stalk and leaf of Suaeda salsa and were identified based on morphological, physiological-biochemical properties, API and 16S rRNA sequence analysis. Isolates were evaluated for their ACC deaminase, antifungal, protease activity, siderophores and phytohormones, such as indole-3-acetic acid, gibberellic acid and abscisic acid production, as well as atmospheric nitrogen fixation and phosphate solubilization. Four ACC deaminase-containing endophytic bacteria strains named as LP11, SS12, TW1 and TW2 were isolated and identified as Pseudomonas oryzihabitans, Pseudomonas sp., Pantoea agglomerans and Pseudomonas putida respectively. All the strains possessed the phosphate-solubilizing ability and could produce siderophores and phytohormones more or less. None of them could fix atmospheric nitrogen or produce protease. Only strain SS12 showed antagonism against two phytopathogenic fungi viz Fusarium oxysporum f. sp. conglutinans and F. oxysporum f. sp. cucumerinum. ACC deaminase-containing endophytic bacteria of Pseudomonas sp. and Pantoea sp. isolated from halophyte Suaeda salsa have abundant biological characteristics related to plant growth promotion, stress homeostasis regulation and biocontrol activity.

Optimatization of transient transformation methods to study gene expression in Musa acuminata (AAA group) cultivar Ambon Lumut

NASA Astrophysics Data System (ADS)

Prayuni, Kinasih; Dwivany, Fenny M.

2015-09-01

Banana is classified as a climateric fruit, whose ripening is regulated by ethylene. Ethylene is synthesized from ACC (1-aminocyclopropane-1-carboxylic acid) by ACC oxidase enzyme which is encoded by ACO gene. Controling an important gene expression in ethylene biosynthesis pathway has became a target to delay the ripening process. Therefore in the previous study we have designed a MaACO-RNAi construct to control MaACO gene expression. In this research, we study the effectiveness of different transient transformation methods to deliver the construct. Direct injection, with or no vaccum infiltration methods were used to deliver MaACO-RNAi construct. All of the methods succesfully deliver the construct into banana fruits based on RT-PCR result.

Interaction of Light and Ethylene on Stem Gravitropism

NASA Technical Reports Server (NTRS)

Harrison, Marcia A.

1996-01-01

The major objective of this study was to evaluate light-regulated ethylene production during gravitropic bending in etiolated pea stems. Previous investigations indicated that ethylene production increases after gravistimulation and is associated with the later (counter-reactive) phase of bending. Additionally, changes in the counter-reaction and locus of curvature during gravitropism are greatly influenced by red light and ethylene production. Ethylene production may be regulated by the levels of available precursor (1-aminocyclopropane-l-carboxylic acid, ACC) via its synthesis, conjugation to malonyl-ACC or glutamyl-ACC, or oxidation to ethylene. The regulation of ethylene production by quantifying ACC and conjugated ACC levels in gravistimulated pea stemswas examined. Also measured was the changes in protein and enzyme activity associated with gravitropic curvature by electrophoretic and spectrophotometric techniques. An image analysis system was used to visualize and quantify enzymatic activity and transcriptional products in gravistimulated and red-light treated etiolated pea stem tissues.

Autoinhibition of Ethylene Production in Citrus Peel Discs 1

PubMed Central

Riov, Joseph; Yang, Shang Fa

1982-01-01

Wound ethylene formation induced in flavede tissue of citrus fruit (Citrus paradisi MacFad. cv. Ruby Red) by slicing was almost completely inhibited by exogenous ethylene. The inhibition lasted for at least 6 hours after removal of exogenous ethylene and was then gradually relieved. The extent of inhibition was dependent upon the concentration of ethylene (1 to 10 microliters/liter) and the duration of treatment. The increase in wound ethylene production in control discs was paralleled by an increase in 1-aminocyclopropane-1-carboxylic acid (AAC) content, whereas in ethylene-treated discs there was little increase in ACC content. Application of ACC completely restored ethylene production in ethylene-pretreated discs, indicating that the conversion of ACC to ethylene is not impaired by the presence of ethylene. Thus, autoinhibition of ethylene synthesis was exerted by reducing the availability of ACC. Ethylene treatment resulted in a decrease in extractable ACC synthase activity, but this decrease was too small to account for the marked inhibition of ACC formation. The data indicate that autoinhibition of ethylene production in citrus flavede discs results from suppression of ACC formation through repression of the synthesis of ACC synthase and inhibition of its activity. PMID:16662276

Delay of flower senescence by bacterial endophytes expressing 1-aminocyclopropane-1-carboxylate deaminase.

PubMed

Ali, S; Charles, T C; Glick, B R

2012-11-01

The ability of 1-aminocyclopropane-1-carboxylate (ACC) deaminase-containing plant growth-promoting bacterial (PGPB) endophytes Pseudomonas fluorescens YsS6 and Pseudomonas migulae 8R6, their ACC deaminase minus mutants and the rhizospheric plant growth-promoting bacterium Pseudomonas putida UW4 to delay the senescence of mini carnation cut flowers was assessed. Fresh cut flowers were incubated with either a bacterial cell suspension, the ethylene precursor ACC, the ethylene inhibitor l-α-(aminoethoxyvinyl)-glycine or 0·85% NaCl at room temperature for 11 days. Levels of flower senescence were recorded every other day. To verify the presence of endophytes inside the plant tissues, scanning electron microscopy was performed. Among all treatments, flowers treated with wild-type ACC deaminase-containing endophytic strains exhibited the most significant delay in flower senescence, while flowers treated with the ACC deaminase minus mutants senesced at a rate similar to the control. Flowers treated with Ps. putida UW4 senesced more rapidly than untreated control flowers. The only difference between wild-type and mutant bacterial endophytes was ACC deaminase activity so that it may be concluded that this enzyme is directly responsible for the significant delay in flower senescence. Despite containing ACC deaminase activity, Ps. putida UW4 is not taken up by the cut flowers and therefore has no effect on prolonging their shelf life. The world-wide cut flower industry currently uses expensive and potentially environmentally dangerous chemical inhibitors of ethylene to prolong the shelf life of cut flowers. The use of PGPB endophytes with ACC deaminase activity has the potential to replace the chemicals that are currently used by the cut flower industry. © 2012 The Authors Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

Defense Responses in Aspen with Altered Pectin Methylesterase Activity Reveal the Hormonal Inducers of Tyloses1[OPEN

PubMed Central

Leśniewska, Joanna; Krzesłowska, Magdalena; Kushwah, Sunita; Sundberg, Björn; Moritz, Thomas

2017-01-01

Tyloses are ingrowths of parenchyma cells into the lumen of embolized xylem vessels, thereby protecting the remaining xylem from pathogens. They are found in heartwood, sapwood, and in abscission zones and can be induced by various stresses, but their molecular triggers are unknown. Here, we report that down-regulation of PECTIN METHYLESTERASE1 (PtxtPME1) in aspen (Populus tremula × tremuloides) triggers the formation of tyloses and activation of oxidative stress. We tested whether any of the oxidative stress-related hormones could induce tyloses in intact plantlets grown in sterile culture. Jasmonates, including jasmonic acid (JA) and methyl jasmonate, induced the formation of tyloses, whereas treatments with salicylic acid (SA) and 1-aminocyclopropane-1-carboxylic acid (ACC) were ineffective. SA abolished the induction of tyloses by JA, whereas ACC was synergistic with JA. The ability of ACC to stimulate tyloses formation when combined with JA depended on ethylene (ET) signaling, as shown by a decrease in the response in ET-insensitive plants. Measurements of internal ACC and JA concentrations in wild-type and ET-insensitive plants treated simultaneously with these two compounds indicated that ACC and JA regulate each other’s concentration in an ET-dependent manner. The findings indicate that jasmonates acting synergistically with ethylene are the key molecular triggers of tyloses. PMID:27923986

Effects of Low O2 Root Stress on Ethylene Biosynthesis in Tomato Plants (Lycopersicon esculentum Mill cv Heinz 1350) 1

PubMed Central

Wang, Tzann-Wei; Arteca, Richard N.

1992-01-01

Low O2 conditions were obtained by flowing N2 through the solution in which the tomato plants (Lycopersicon esculentum Mill cv Heinz 1350) were growing. Time course experiments revealed that low O2 treatments stimulated 1-aminocyclopropane-1-carboxylate (ACC) synthase production in the roots and leaves. After the initiation of low O2 conditions, ACC synthase activity and ACC content in the roots increased and reached a peak after 12 and 20 hours, respectively. The conversion of ACC to ethylene in the roots was inhibited by low levels of O2, and ACC was apparently transported to the leaves where it was converted to ethylene. ACC synthase activity in the leaves was also stimulated by low O2 treatment to the roots, reaching a peak after 24 hours. ACC synthase levels were enhanced by cobalt chloride and aminooxyacetic acid (AOA), although they inhibited ethylene production. Cobalt chloride enhanced ACC synthase only in combination with low O2 conditions in the roots. Under aeration, AOA stimulated ACC synthase activity in both the roots and leaves. However, in combination with low O2 conditions, AOA caused a stimulation in ACC synthase activity in the leaves and no effect in the roots. PMID:16668654

Defense Responses in Aspen with Altered Pectin Methylesterase Activity Reveal the Hormonal Inducers of Tyloses.

PubMed

Leśniewska, Joanna; Öhman, David; Krzesłowska, Magdalena; Kushwah, Sunita; Barciszewska-Pacak, Maria; Kleczkowski, Leszek A; Sundberg, Björn; Moritz, Thomas; Mellerowicz, Ewa J

2017-02-01

Tyloses are ingrowths of parenchyma cells into the lumen of embolized xylem vessels, thereby protecting the remaining xylem from pathogens. They are found in heartwood, sapwood, and in abscission zones and can be induced by various stresses, but their molecular triggers are unknown. Here, we report that down-regulation of PECTIN METHYLESTERASE1 (PtxtPME1) in aspen (Populus tremula × tremuloides) triggers the formation of tyloses and activation of oxidative stress. We tested whether any of the oxidative stress-related hormones could induce tyloses in intact plantlets grown in sterile culture. Jasmonates, including jasmonic acid (JA) and methyl jasmonate, induced the formation of tyloses, whereas treatments with salicylic acid (SA) and 1-aminocyclopropane-1-carboxylic acid (ACC) were ineffective. SA abolished the induction of tyloses by JA, whereas ACC was synergistic with JA. The ability of ACC to stimulate tyloses formation when combined with JA depended on ethylene (ET) signaling, as shown by a decrease in the response in ET-insensitive plants. Measurements of internal ACC and JA concentrations in wild-type and ET-insensitive plants treated simultaneously with these two compounds indicated that ACC and JA regulate each other's concentration in an ET-dependent manner. The findings indicate that jasmonates acting synergistically with ethylene are the key molecular triggers of tyloses. © 2017 American Society of Plant Biologists. All Rights Reserved.

Ethylene Production and 1-Aminocyclopropane-1-Carboxylic Acid Conjugation in Thermoinhibited Cicer arietinum L. Seeds 1

PubMed Central

Gallardo, Mercedes; Delgado, María del Mar; Sánchez-Calle, Isabel María; Matilla, Angel Jesús

1991-01-01

The effect of supraoptimal temperatures (30°C, 35°C) on germination and ethylene production of Cicer arietinum (chick-pea) seeds was measured. Compared with a 25°C control, these temperatures inhibited both germination and ethylene production. The effect of supraoptimal temperatures could be alleviated by treating the seeds with ethylene. It was concluded that one effect of high temperature on germination was due to its negative effect on ethylene production. This inhibitory effect of high temperature was due to increased conjugation of 1-aminocyclopropane-1-carboxylic acid to 1-(malonylamino)cyclopropane-1-carboxylic acid and to an inhibition of ethylene-forming enzyme activity. PMID:16668358

The final step of the ethylene biosynthesis pathway in turnip tops (Brassica rapa): molecular characterization of the 1-aminocyclopropane-1-carboxylate oxidase BrACO1 throughout zygotic embryogenesis and germination of heterogeneous seeds.

PubMed

Del Carmen Rodríguez-Gacio, María; Nicolás, Carlos; Matilla, Angel Jesús

2004-05-01

In a previous report from the present authors, it was shown that the 1-aminocyclopropane-1-carboxylate (ACC) oxidation may play a crucial role during zygotic embryogenesis of turnip tops seeds. The present study was performed to elucidate the contribution of the silique-wall and seeds in ethylene production during this developmental process. ACC content in the silique wall is only higher than in seeds during the middle phases of zygotic embryogenesis. The ACC-oxidase (ACO) activity peaks in the silique-wall and seeds during the onset of embryogenesis, declining gradually afterwards, being undetectable during desiccation period. Using reverse transcriptase-polymerase chain reaction, one cDNA clone coding for an ACO and called BrACO1, was isolated. The deduced protein for BrACO1 has a molecular weight of 36.8 kDa and a high homology with other crucifer ACOs. The heterologous expression of this cDNA confirmed that BrACO1 is an ACO. The expression of this gene was high during the first phases of silique-wall development, low during the middle phases and undetectable during desiccation. By contrast, BrACO1 transcript was accumulated only in the earliest phases of seed embryogenesis and may participate in the highest ACO activity and ethylene production by seeds at the beginning of embryogenesis. Finally, in this work a correlation between the heterogeneity of Brassica rapa L. cv. Rapa seeds and the ability to oxidize the ACC to ethylene has been demonstrated.

Methylobacterium oryzae sp. nov., an aerobic, pink-pigmented, facultatively methylotrophic, 1-aminocyclopropane-1-carboxylate deaminase-producing bacterium isolated from rice.

PubMed

Madhaiyan, Munusamy; Kim, Byung-Yong; Poonguzhali, Selvaraj; Kwon, Soon-Wo; Song, Myung-Hee; Ryu, Jeoung-Hyun; Go, Seung-Joo; Koo, Bon-Sung; Sa, Tong-Min

2007-02-01

A pink-pigmented, facultatively methylotrophic bacterium, strain CBMB20T, isolated from stem tissues of rice, was analysed by a polyphasic approach. Strain CBMB20T utilized 1-aminocyclopropane 1-carboxylate (ACC) as a nitrogen source and produced ACC deaminase. It was related phylogenetically to members of the genus Methylobacterium. 16S rRNA gene sequence analysis indicated that strain CBMB20T was most closely related to Methylobacterium fujisawaense, Methylobacterium radiotolerans and Methylobacterium mesophilicum; however, DNA-DNA hybridization values were less than 70 % with the type strains of these species. The DNA G+C content of strain CBMB20T was 70.6 mol%. The study presents a detailed phenotypic characterization of strain CBMB20T that allows its differentiation from other Methylobacterium species. In addition, strain CBMB20T is the only known member of the genus Methylobacterium to be described from the phyllosphere of rice. Based on the data presented, strain CBMB20T represents a novel species in the genus Methylobacterium, for which the name Methylobacterium oryzae sp. nov. is proposed, with strain CBMB20T (=DSM 18207T=LMG 23582T=KACC 11585T) as the type strain.

Leaf Abscission Induced by Ethylene in Water-Stressed Intact Seedlings of Cleopatra Mandarin Requires Previous Abscisic Acid Accumulation in Roots.

PubMed Central

Gomez-Cadenas, A.; Tadeo, F. R.; Talon, M.; Primo-Millo, E.

1996-01-01

The involvement of abscisic acid (ABA) in the process of leaf abscission induced by 1-aminocyclopropane-1-carboxylic acid (ACC) transported from roots to shoots in Cleopatra mandarin (Citrus reshni Hort. ex Tan.) seedlings grown under water stress was studied using norflurazon (NF). Water stress induced both ABA (24-fold) and ACC (16-fold) accumulation in roots and arrested xylem flow. Leaf bulk ABA also increased (8-fold), although leaf abscission did not occur. Shortly after rehydration, root ABA and ACC returned to their prestress levels, whereas sharp and transitory increases of ACC (17-fold) and ethylene (10-fold) in leaves and high percentages of abscission (up to 47%) were observed. NF suppressed the ABA and ACC accumulation induced by water stress in roots and the sharp increases of ACC and ethylene observed after rewatering in leaves. NF also reduced leaf abscission (7-10%). These results indicate that water stress induces root ABA accumulation and that this is required for the process of leaf abscission to occur. It was also shown that exogenous ABA increases ACC levels in roots but not in leaves. Collectively, the data suggest that ABA, the primary sensitive signal to water stress, modulates the levels of ethylene, which is the hormonal activator of leaf abscission. This assumption implies that root ACC levels are correlated with root ABA amounts in a dependent way, which eventually links water status to an adequate, protective response such as leaf abscission. PMID:12226398

Inoculation of Soil with Plant Growth Promoting Bacteria Producing 1-Aminocyclopropane-1-Carboxylate Deaminase or Expression of the Corresponding acdS Gene in Transgenic Plants Increases Salinity Tolerance in Camelina sativa

PubMed Central

Heydarian, Zohreh; Yu, Min; Gruber, Margaret; Glick, Bernard R.; Zhou, Rong; Hegedus, Dwayne D.

2016-01-01

Camelina sativa (camelina) is an oilseed crop touted for use on marginal lands; however, it is no more tolerant of soil salinity than traditional crops, such as canola. Plant growth-promoting bacteria (PGPB) that produce 1-aminocyclopropane-1-carboxylate deaminase (ACC deaminase) facilitate plant growth in the presence of abiotic stresses by reducing stress ethylene. Rhizospheric and endophytic PGPB and the corresponding acdS- mutants of the latter were examined for their ability to enhance tolerance to salt in camelina. Stimulation of growth and tolerance to salt was correlated with ACC deaminase production. Inoculation of soil with wild-type PGPB led to increased shoot length in the absence of salt, and increased seed production by approximately 30–50% under moderately saline conditions. The effect of ACC deaminase was further examined in transgenic camelina expressing a bacterial gene encoding ACC deaminase (acdS) under the regulation of the CaMV 35S promoter or the root-specific rolD promoter. Lines expressing acdS, in particular those using the rolD promoter, showed less decline in root length and weight, increased seed production, better seed quality and higher levels of seed oil production under salt stress. This study clearly demonstrates the potential benefit of using either PGPB that produce ACC deaminase or transgenic plants expressing the acdS gene under the control of a root-specific promoter to facilitate plant growth, seed production and seed quality on land that is not normally suitable for the majority of crops due to high salt content. PMID:28018305

Relationship between endogenous hormonal content and somatic organogenesis in callus of peach (Prunus persica L. Batsch) cultivars and Prunus persica×Prunus dulcis rootstocks.

PubMed

Pérez-Jiménez, Margarita; Cantero-Navarro, Elena; Pérez-Alfocea, Francisco; Le-Disquet, Isabel; Guivarc'h, Anne; Cos-Terrer, José

2014-05-01

The relationship between endogenous hormones content and the induction of somatic peach plant was studied. To induce multiple shoots from callus derived from the base of stem explants of the scion cultivars 'UFO-3', 'Flariba' and 'Alice Bigi', and the peach×almond rootstocks 'Garnem' and 'GF677', propagated plants were cultured on Murashige and Skoog salts augmented with 0.1mgL(-1) of indolebutyric acid, 1mgL(-1) of 6-benzylaminopurine and 3% sucrose. The highest regeneration rate was obtained with the peach×almond rootstocks. Endogenous levels of abscisic acid (ABA), indole-3-acetic acid (IAA), zeatin (Z), zeatin riboside (ZR), ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), salicylic acid (SA), and jasmonic acid (JA) were analyzed in the organogenic callus. Lower levels of several hormones, namely Z, ZR, ABA, and ACC were found in the peach×almond rootstock compared to peach cultivars, while IAA and SA presented inconclusive returns. These results suggest that the difference in somatic organogenesis capacity observed in peach and peach×almond hybrids is markedly affected by the endogenous hormonal content of the studied genotypes. Copyright © 2014 Elsevier GmbH. All rights reserved.

ETHY. A Theory of Fruit Climacteric Ethylene Emission1

PubMed Central

Génard, Michel; Gouble, Barbara

2005-01-01

A theory of fruit climacteric ethylene emission was developed and used as the basis of a simulation model called ETHY. According to the theory, the biosynthetic pathway of ethylene is supplied by ATP and is regulated by 1-aminocyclopropane-1-carboxylic acid (ACC) synthase and ACC oxidase. The conjugation of ACC with malonate to form MACC was taken into account as a way to decrease the availability of ACC. Because of the seasonal increase of fruit volume, the dilution of biochemical compounds used in ETHY was taken into account. Finally, the ethylene diffusion across the skin was considered. The theory took into account the effect of temperature and O2 and CO2 internal concentrations on ethylene. The model was applied to peach (Prunus persica) fruit over 3 years, several leaf:fruit ratios, and irrigation conditions. An adequate ethylene increase was predicted without considering any increase in respiration during the ripening period, which suggests that the respiratory climacteric may not be required for ripening. Another important result of this study is the high sensitivity of ETHY to the parameters involved in the calculation of ACC oxidase and ACC synthase activities, ATP production, and skin surface and permeability. ETHY was also highly sensitive to changes in fruit growth and temperature. PMID:16143642

Oxygen control of ethylene biosynthesis during seed development in Arabidopsis thaliana (L.) Heynh

NASA Technical Reports Server (NTRS)

Ramonell, K. M.; McClure, G.; Musgrave, M. E.

2002-01-01

An unforeseen side-effect on plant growth in reduced oxygen is the loss of seed production at concentrations around 25% atmospheric (50 mmol mol-1 O2). In this study, the model plant Arabidopsis thaliana (L.) Heynh. cv. 'Columbia' was used to investigate the effect of low oxygen on ethylene biosynthesis during seed development. Plants were grown in a range of oxygen concentrations (210 [equal to ambient], 160, 100, 50 and 25 mmol mol-1) with 0.35 mmol mol-1 CO2 in N2. Ethylene in full-sized siliques was sampled using gas chromatography, and viable seed production was determined at maturity. Molecular analysis of ethylene biosynthesis was accomplished using cDNAs encoding 1-aminocyclopropane-1-carboxylic acid (ACC) synthase and ACC oxidase in ribonuclease protection assays and in situ hybridizations. No ethylene was detected in siliques from plants grown at 50 and 25 mmol mol-1 O2. At the same time, silique ACC oxidase mRNA increased three-fold comparing plants grown under the lowest oxygen with ambient controls, whereas ACC synthase mRNA was unaffected. As O2 decreased, tissue-specific patterning of ACC oxidase and ACC synthase gene expression shifted from the embryo to the silique wall. These data demonstrate how low O2 modulates the activity and expression of the ethylene biosynthetic pathway during seed development in Arabidopsis.

Enhancement of growth and salt tolerance of red pepper seedlings (Capsicum annuum L.) by regulating stress ethylene synthesis with halotolerant bacteria containing 1-aminocyclopropane-1-carboxylic acid deaminase activity.

PubMed

Siddikee, Md Ashaduzzaman; Glick, Bernard R; Chauhan, Puneet S; Yim, Woo jong; Sa, Tongmin

2011-04-01

Three 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase-producing halotolerant bacteria were isolated from West Coast soil of Yellow Sea, Incheon, South Korea and evaluated for their efficiency in improving red pepper plant growth under salt stress. The strains RS16, RS656 and RS111 were identified by 16S rRNA gene sequencing as Brevibacterium iodinum, Bacillus licheniformis and Zhihengliuela alba, respectively. Two hour exposure of 100, 150 and 200 mM NaCl stress on 8 day old red pepper seedlings caused 44, 64 and 74% increase ethylene production, while at 150 mM NaCl stress, inoculation of B. licheniformis RS656, Z. alba RS111, and Br. iodinum RS16 reduces ethylene production by 44, 53 and 57%, respectively. Similarly, 3 week old red pepper plants were subjected to salt stress for two weeks and approximately ∼50% reduction in growth recorded at 150 mM NaCl stress compared to negative control whereas bacteria inoculation significantly increase the growth compared to positive control. Salt stress also caused 1.3-fold reduction in the root/shoot dry weight ratio compared to the absence of salt while bacteria inoculation retained the biomass allocation similar to control plants. The salt tolerance index (ratio of biomass of salt stressed to non-stressed plant) was also significantly increased in inoculated plants compared to non-inoculated. Increase nutrient uptakes under salt stress by red pepper further evident that bacteria inoculation ameliorates salt stress effect. In summary, this study indicates that the use of ACC deaminase-producing halotolerant bacteria mitigates the salt stress by reducing salt stress-induced ethylene production on growth of red pepper plants. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Selenium delays tomato fruit ripening by inhibiting ethylene biosynthesis and enhancing the antioxidant defense system.

PubMed

Zhu, Zhu; Chen, Yanli; Shi, Guoqing; Zhang, Xueji

2017-03-15

The antioxidant activity of selenium (Se) detoxifies reactive oxygen species (ROS) in plants and animals. In the present study, we elucidated the mechanism underlying Se induced fruit development and ripening. Our study showed that foliar pretreatment with 1mgL -1 sodium selenate effectively delayed fruit ripening and maintained fruit quality. Gene expression studies revealed that the repression of ethylene biosynthetic genes 1-aminocyclopropane-1-carboxylic acid (ACC) synthase and ACC oxidase decreased ethylene production and respiration rate. Moreover, Se treatment probably boosted the antioxidant defense system to reduce ROS generation and membrane damage. The enhanced antioxidative effect was attributed to higher glutathione content and increased activity of enzymes such as glutathione peroxidase and glutathione reductase. The upregulation of respiratory burst oxidase homologue genes in tomato fruit may also contribute to the enhanced antioxidative effect. Selenium treatment represents a promising strategy for delaying ripening and extending the shelf life of tomato fruit. Copyright © 2016 Elsevier Ltd. All rights reserved.

Characterization of Ethylene Biosynthesis Associated with Ripening in Banana Fruit1

PubMed Central

Liu, Xuejun; Shiomi, Shinjiro; Nakatsuka, Akira; Kubo, Yasutaka; Nakamura, Reinosuke; Inaba, Akitsugu

1999-01-01

We investigated the characteristics of ethylene biosynthesis associated with ripening in banana (Musa sp. [AAA group, Cavendish subgroup] cv Grand Nain) fruit. MA-ACS1 encoding 1-aminocyclopropane-1-carboxylic acid (ACC) synthase in banana fruit was the gene related to the ripening process and was inducible by exogenous ethylene. At the onset of the climacteric period in naturally ripened fruit, ethylene production increased greatly, with a sharp peak concomitant with an increase in the accumulation of MA-ACS1 mRNA, and then decreased rapidly. At the onset of ripening, the in vivo ACC oxidase activity was enhanced greatly, followed by an immediate and rapid decrease. Expression of the MA-ACO1 gene encoding banana ACC oxidase was detectable at the preclimacteric stage, increased when ripening commenced, and then remained high throughout the later ripening stage despite of a rapid reduction in the ACC oxidase activity. This discrepancy between enzyme activity and gene expression of ACC oxidase could be, at least in part, due to reduced contents of ascorbate and iron, cofactors for the enzyme, during ripening. Addition of these cofactors to the incubation medium greatly stimulated the in vivo ACC oxidase activity during late ripening stages. The results suggest that ethylene production in banana fruit is regulated by transcription of MA-ACS1 until climacteric rise and by reduction of ACC oxidase activity possibly through limited in situ availability of its cofactors once ripening has commenced, which in turn characterizes the sharp peak of ethylene production. PMID:10594112

Novel Rhizosphere Soil Alleles for the Enzyme 1-Aminocyclopropane-1-Carboxylate Deaminase Queried for Function with an In Vivo Competition Assay

PubMed Central

Jin, Zhao; Di Rienzi, Sara C.; Janzon, Anders; Werner, Jeff J.; Angenent, Largus T.; Dangl, Jeffrey L.; Fowler, Douglas M.

2015-01-01

Metagenomes derived from environmental microbiota encode a vast diversity of protein homologs. How this diversity impacts protein function can be explored through selection assays aimed to optimize function. While artificially generated gene sequence pools are typically used in selection assays, their usage may be limited because of technical or ethical reasons. Here, we investigate an alternative strategy, the use of soil microbial DNA as a starting point. We demonstrate this approach by optimizing the function of a widely occurring soil bacterial enzyme, 1-aminocyclopropane-1-carboxylate (ACC) deaminase. We identified a specific ACC deaminase domain region (ACCD-DR) that, when PCR amplified from the soil, produced a variant pool that we could swap into functional plasmids carrying ACC deaminase-encoding genes. Functional clones of ACC deaminase were selected for in a competition assay based on their capacity to provide nitrogen to Escherichia coli in vitro. The most successful ACCD-DR variants were identified after multiple rounds of selection by sequence analysis. We observed that previously identified essential active-site residues were fixed in the original unselected library and that additional residues went to fixation after selection. We identified a divergent essential residue whose presence hints at the possible use of alternative substrates and a cluster of neutral residues that did not influence ACCD performance. Using an artificial ACCD-DR variant library generated by DNA oligomer synthesis, we validated the same fixation patterns. Our study demonstrates that soil metagenomes are useful starting pools of protein-coding-gene diversity that can be utilized for protein optimization and functional characterization when synthetic libraries are not appropriate. PMID:26637602

ETHY. A theory of fruit climacteric ethylene emission.

PubMed

Génard, Michel; Gouble, Barbara

2005-09-01

A theory of fruit climacteric ethylene emission was developed and used as the basis of a simulation model called ETHY. According to the theory, the biosynthetic pathway of ethylene is supplied by ATP and is regulated by 1-aminocyclopropane-1-carboxylic acid (ACC) synthase and ACC oxidase. The conjugation of ACC with malonate to form MACC was taken into account as a way to decrease the availability of ACC. Because of the seasonal increase of fruit volume, the dilution of biochemical compounds used in ETHY was taken into account. Finally, the ethylene diffusion across the skin was considered. The theory took into account the effect of temperature and O(2) and CO(2) internal concentrations on ethylene. The model was applied to peach (Prunus persica) fruit over 3 years, several leaf:fruit ratios, and irrigation conditions. An adequate ethylene increase was predicted without considering any increase in respiration during the ripening period, which suggests that the respiratory climacteric may not be required for ripening. Another important result of this study is the high sensitivity of ETHY to the parameters involved in the calculation of ACC oxidase and ACC synthase activities, ATP production, and skin surface and permeability. ETHY was also highly sensitive to changes in fruit growth and temperature.

Cyanide Metabolism in Relation to Ethylene Production in Plant Tissues 1

PubMed Central

Yip, Wing-Kin; Yang, Shang Fa

1988-01-01

HCN is the putative product of C-1 and amino moieties of 1-aminocyclopropane-1-carboxylic acid (ACC) during its conversion to ethylene. In apple (Malus sylvestrus Mill.) slices or auxin-treated mungbean (Vigna radiata L.) hypocotyls, which produced ethylene at high rates, the steady state concentration of HCN was found to be no higher than 0.2 micromolar, which was too low to inhibit respiration (reported Ki for HCN to inhibit respiration was 10-20 micromolar). However, these tissues became cyanogenic when treated with ACC, the precursor of ethylene, and with 2-aminoxyacetic acid, which inhibits β-cyanoalanine synthase, the main enzyme to detoxify HCN; the HCN levels in these tissues went up to 1.7 and 8.1 micromolar, respectively. Although ethylene production by avocado (Persea gratissima) and apple fruits increased several hundred-fold during ripening, β-cyanoalanine synthase activity increased only one- to two-fold. These findings support the notion that HCN is a co-product of ethylene biosynthesis and that the plant tissues possess ample capacity to detoxify HCN formed during ethylene biosynthesis so that the concentration of HCN in plant tissues is kept at a low level. PMID:16666329

Antioxidative properties of the essential oil from Pinus mugo.

PubMed

Grassmann, Johanna; Hippeli, Susanne; Vollmann, Renate; Elstner, Erich F

2003-12-17

The essential oil from Pinus mugo (PMEO) was tested on its antioxidative capacity. For this purpose, several biochemical test systems were chosen (e.g., the Fenton System, the xanthine oxidase assay, or the copper-induced oxidation of low-density lipoprotein (LDL)). The results show that there is moderate or weak antioxidative activity when tested in aqueous environments, like in the Fenton system, xanthine oxidase induced superoxide radical formation, or in the HOCl driven fragmentation of 1-aminocyclopropane-1-carboxylic acid (ACC). In contrast, when tested in more lipophilic environments (e.g., the ACC-cleavage by activated neutrophils in whole blood) the PMEO exhibits good antioxidative activity. PMEO does also show good antioxidative capacity in another lipophilic test system (i.e., the copper induced oxidation of LDL). Some components of PMEO (i.e., Delta(3)-carene, camphene, alpha-pinene, (+)-limonene and terpinolene) were also tested. As the PMEO, they showed weak or no antioxidant activity in aqueous environments, but some of them were effective antioxidants regarding ACC-cleavage by activated neutrophils in whole blood or copper-induced LDL-oxidation. Terpinolene, a minor component of PMEO, exhibited remarkable protection against LDL-oxidation.

Mechanical perturbation-induced ethylene releases apical dominance in Pharbitis nil by restricting shoot growth

NASA Technical Reports Server (NTRS)

Prasad, T. K.; Cline, M. G.

1985-01-01

Mechanical perturbation (MP, rubbing) or internodes of Pharbitis nil shoots initiates release of lateral buds (LB) from apical dominance within 48 h. Evidence is presented which suggests that MP promotion of LB outgrowth is mediated by ethylene-induced restriction of main shoot growth. Ethylene production in the internodes is stimulated by MP within 2 h. Effects of MP are mimicked by treatments with 1-aminocyclopropane-1-carboxylic acid (ACC) and are negated by the inhibitors of ethylene production or action, aminoethoxy vinylglycine (AVG) and AgNO3. The fact that effects of MP, ACC, and ethylene inhibitors are observed to occur on main shoot growth at least 24 h before they are observed to occur on LB growth suggests a possible cause and effect relationship. MP also causes an increase in internode diameter. MP stimulation of ethylene production appears to be mediated by ACC synthase. The results of this study and our previous studies suggest that apical dominance may be released by any mechanism which induces ethylene restriction of main shoot growth.

A type III ACC synthase, ACS7, is involved in root gravitropism in Arabidopsis thaliana

PubMed Central

Chang, Ing-Feng

2013-01-01

Ethylene is an important plant hormone that regulates developmental processes in plants. The ethylene biosynthesis pathway is a highly regulated process at both the transcriptional and post-translational level. The transcriptional regulation of these ethylene biosynthesis genes is well known. However, post-translational modifications of the key ethylene biosynthesis enzyme 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS) are little understood. In vitro kinase assays were conducted on the type III ACS, AtACS7, fusion protein and peptides to determine whether the AtACS7 protein can be phosphorylated by calcium-dependent protein kinase (CDPK). AtACS7 was phosphorylated at Ser216, Thr296, and Ser299 by AtCDPK16 in vitro. To investigate further the function of the ACS7 gene in Arabidopsis, an acs7-1 loss-of-function mutant was isolated. The acs7-1 mutant exhibited less sensitivity to the inhibition of root gravitropism by treatment with the calcium chelator ethylene glycol tetraacetic acid (EGTA). Seedlings were treated with gradient concentrations of ACC. The results showed that a certain concentration of ethylene enhanced the gravity response. Moreover, the acs7-1 mutant was less sensitive to inhibition of the gravity response by treatment with the auxin polar transport inhibitor 1-naphthylphthalamic acid, but exogenous ACC application recovered root gravitropism. Altogether, the results indicate that AtACS7 is involved in root gravitropism in a calcium-dependent manner in Arabidopsis. PMID:23943848

A type III ACC synthase, ACS7, is involved in root gravitropism in Arabidopsis thaliana.

PubMed

Huang, Shih-Jhe; Chang, Chia-Lun; Wang, Po-Hsun; Tsai, Min-Chieh; Hsu, Pang-Hung; Chang, Ing-Feng

2013-11-01

Ethylene is an important plant hormone that regulates developmental processes in plants. The ethylene biosynthesis pathway is a highly regulated process at both the transcriptional and post-translational level. The transcriptional regulation of these ethylene biosynthesis genes is well known. However, post-translational modifications of the key ethylene biosynthesis enzyme 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS) are little understood. In vitro kinase assays were conducted on the type III ACS, AtACS7, fusion protein and peptides to determine whether the AtACS7 protein can be phosphorylated by calcium-dependent protein kinase (CDPK). AtACS7 was phosphorylated at Ser216, Thr296, and Ser299 by AtCDPK16 in vitro. To investigate further the function of the ACS7 gene in Arabidopsis, an acs7-1 loss-of-function mutant was isolated. The acs7-1 mutant exhibited less sensitivity to the inhibition of root gravitropism by treatment with the calcium chelator ethylene glycol tetraacetic acid (EGTA). Seedlings were treated with gradient concentrations of ACC. The results showed that a certain concentration of ethylene enhanced the gravity response. Moreover, the acs7-1 mutant was less sensitive to inhibition of the gravity response by treatment with the auxin polar transport inhibitor 1-naphthylphthalamic acid, but exogenous ACC application recovered root gravitropism. Altogether, the results indicate that AtACS7 is involved in root gravitropism in a calcium-dependent manner in Arabidopsis.

Bacterial Modulation of Plant Ethylene Levels

PubMed Central

Gamalero, Elisa; Glick, Bernard R.

2015-01-01

A focus on the mechanisms by which ACC deaminase-containing bacteria facilitate plant growth.Bacteria that produce the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase, when present either on the surface of plant roots (rhizospheric) or within plant tissues (endophytic), play an active role in modulating ethylene levels in plants. This enzyme activity facilitates plant growth especially in the presence of various environmental stresses. Thus, plant growth-promoting bacteria that express ACC deaminase activity protect plants from growth inhibition by flooding and anoxia, drought, high salt, the presence of fungal and bacterial pathogens, nematodes, and the presence of metals and organic contaminants. Bacteria that express ACC deaminase activity also decrease the rate of flower wilting, promote the rooting of cuttings, and facilitate the nodulation of legumes. Here, the mechanisms behind bacterial ACC deaminase facilitation of plant growth and development are discussed, and numerous examples of the use of bacteria with this activity are summarized. PMID:25897004

RNA interference of 1-aminocyclopropane-1-carboxylic acid oxidase (ACO1 and ACO2) genes expression prolongs the shelf life of Eksotika (Carica papaya L.) papaya fruit.

PubMed

Sekeli, Rogayah; Abdullah, Janna Ong; Namasivayam, Parameswari; Muda, Pauziah; Abu Bakar, Umi Kalsom; Yeong, Wee Chien; Pillai, Vilasini

2014-06-19

The purpose of this study was to evaluate the effectiveness of using RNA interference in down regulating the expression of 1-aminocyclopropane-1-carboxylic acid oxidase gene in Eksotika papaya. One-month old embryogenic calli were separately transformed with Agrobacterium strain LBA 4404 harbouring the three different RNAi pOpOff2 constructs bearing the 1-aminocyclopropane-1-carboxylic acid oxidase gene. A total of 176 putative transformed lines were produced from 15,000 calli transformed, selected, then regenerated on medium supplemented with kanamycin. Integration and expression of the targeted gene in putatively transformed lines were verified by PCR and real-time RT-PCR. Confined field evaluation of a total of 31 putative transgenic lines planted showed a knockdown expression of the targeted ACO1 and ACO2 genes in 13 lines, which required more than 8 days to achieve the full yellow colour (Index 6). Fruits harvested from lines pRNAiACO2 L2-9 and pRNAiACO1 L2 exhibited about 20 and 14 days extended post-harvest shelf life to reach Index 6, respectively. The total soluble solids contents of the fruits ranged from 11 to 14° Brix, a range similar to fruits from non-transformed, wild type seed-derived plants.

A halotolerant Enterobacter sp. displaying ACC deaminase activity promotes rice seedling growth under salt stress.

PubMed

Sarkar, Anumita; Ghosh, Pallab Kumar; Pramanik, Krishnendu; Mitra, Soumik; Soren, Tithi; Pandey, Sanjeev; Mondal, Monohar Hossain; Maiti, Tushar Kanti

2018-01-01

Agricultural productivity is proven to be hampered by the synthesis of reactive oxygen species (ROS) and production of stress-induced ethylene under salinity stress. One-aminocyclopropane-1-carboxylic acid (ACC) is the direct precursor of ethylene synthesized by plants. Bacteria possessing ACC deaminase activity can use ACC as a nitrogen source preventing ethylene production. Several salt-tolerant bacterial strains displaying ACC deaminase activity were isolated from rice fields, and their plant growth-promoting (PGP) properties were determined. Among them, strain P23, identified as an Enterobacter sp. based on phenotypic characteristics, matrix-assisted laser desorption ionization-time of flight mass spectrometry data and the 16S rDNA sequence, was selected as the best-performing isolate for several PGP traits, including phosphate solubilization, IAA production, siderophore production, HCN production, etc. Enterobacter sp. P23 was shown to promote rice seedling growth under salt stress, and this effect was correlated with a decrease in antioxidant enzymes and stress-induced ethylene. Isolation of an acdS mutant strain enabled concluding that the reduction in stress-induced ethylene content after inoculation of strain P23 was linked to ACC deaminase activity. Copyright © 2017 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Inhibition of ethylene production by putrescine alleviates aluminium-induced root inhibition in wheat plants.

PubMed

Yu, Yan; Jin, Chongwei; Sun, Chengliang; Wang, Jinghong; Ye, Yiquan; Zhou, Weiwei; Lu, Lingli; Lin, Xianyong

2016-01-08

Inhibition of root elongation is one of the most distinct symptoms of aluminium (Al) toxicity. Although putrescine (Put) has been identified as an important signaling molecule involved in Al tolerance, it is yet unknown how Put mitigates Al-induced root inhibition. Here, the possible mechanism was investigated by using two wheat genotypes differing in Al resistance: Al-tolerant Xi Aimai-1 and Al-sensitive Yangmai-5. Aluminium caused more root inhibition in Yangmai-5 and increased ethylene production at the root apices compared to Xi Aimai-1, whereas the effects were significantly reversed by ethylene biosynthesis inhibitors. The simultaneous exposure of wheat seedlings to Al and ethylene donor, ethephon, or ethylene biosynthesis precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), increased ethylene production and aggravated root inhibition, which was more pronounced in Xi Aimai-1. In contrast, Put treatment decreased ethylene production and alleviated Al-induced root inhibition in both genotypes, and the effects were more conspicuous in Yangmai-5. Furthermore, our results indicated that Al-induced ethylene production was mediated by ACC synthase (ACS) and ACC oxidase, and that Put decreased ethylene production by inhibiting ACS. Altogether, these findings indicate that ethylene is involved in Al-induced root inhibition and this process could be alleviated by Put through inhibiting ACS activity.

Effects of glucose and ethylene on root hair initiation and elongation in lettuce (Lactuca sativa L.) seedlings.

PubMed

Harigaya, Wakana; Takahashi, Hidenori

2018-05-01

Root hair formation occurs in lettuce seedlings after transfer to an acidic medium (pH 4.0). This process requires cortical microtubule (CMT) randomization in root epidermal cells and the plant hormone ethylene. We investigated the interaction between ethylene and glucose, a new signaling molecule in plants, in lettuce root development, with an emphasis on root hair formation. Dark-grown seedlings were used to exclude the effect of photosynthetically produced glucose. In the dark, neither root hair formation nor the CMT randomization preceding it occurred, even after transfer to the acidic medium (pH 4.0). Adding 1-aminocyclopropane-1-carboxylic-acid (ACC) to the medium rescued the induction, while adding glucose did not. Although CMT randomization occurred when glucose was applied together with ACC, it was somewhat suppressed compared to that in ACC-treated seedlings. This was not due to a decrease in the speed of randomization, but due to lowering of the maximum degree of randomization. Despite the negative effect of glucose on ACC-induced CMT randomization, the density and length of ACC-induced root hairs increased when glucose was also added. The hair-cell length of the ACC-treated seedlings was comparable to that in the combined-treatment seedlings, indicating that the increase in hair density caused by glucose results from an increase in the root hair number. Furthermore, quantitative RT-PCR revealed that glucose suppressed ethylene signaling. These results suggest that glucose has a negative and positive effect on the earlier and later stages of root hair formation, respectively, and that the promotion of the initiation and elongation of root hairs by glucose may be mediated in an ethylene-independent manner.

Role of Ethylene in the Geotropic Response of Bermudagrass (Cynodon dactylon L. Pers.) Stolons 1

PubMed Central

Balatti, Pedro A.; Willemöes, Jorge G.

1989-01-01

We studied the relationship between ethylene and gravity-induced upward bending of bermudagrass (Cynodon dactylon L. Pers.) stolons. Ethylene production begins within 3 hours of the onset of gravistimulation, and increases thereafter until the 15th hour, after which it declines. There is a close positive relationship between ethylene production and upward bending during the first 12 hours of gravistimulation. Incubation of stolons with AgNO3 did not prevent ethylene evolution but delayed upward bending. In addition, ethylene production was 10-fold greater and peaked earlier in gravistimulated nodes incubated with 1-aminocyclopropane 1-carboxylic acid. The gravitational stimulation could be due to an increase in both 1-aminocyclopropane 1-carboxylic acid synthase and the ethylene forming enzyme. The results suggest that ethylene promotes the activity of indoleacetic acid. PMID:16667170

Structural and stereoelectronic insights into oxygenase-catalyzed formation of ethylene from 2-oxoglutarate.

PubMed

Zhang, Zhihong; Smart, Tristan J; Choi, Hwanho; Hardy, Florence; Lohans, Christopher T; Abboud, Martine I; Richardson, Melodie S W; Paton, Robert S; McDonough, Michael A; Schofield, Christopher J

2017-05-02

Ethylene is important in industry and biological signaling. In plants, ethylene is produced by oxidation of 1-aminocyclopropane-1-carboxylic acid, as catalyzed by 1-aminocyclopropane-1-carboxylic acid oxidase. Bacteria catalyze ethylene production, but via the four-electron oxidation of 2-oxoglutarate to give ethylene in an arginine-dependent reaction. Crystallographic and biochemical studies on the Pseudomonas syringae ethylene-forming enzyme reveal a branched mechanism. In one branch, an apparently typical 2-oxoglutarate oxygenase reaction to give succinate, carbon dioxide, and sometimes pyrroline-5-carboxylate occurs. Alternatively, Grob-type oxidative fragmentation of a 2-oxoglutarate-derived intermediate occurs to give ethylene and carbon dioxide. Crystallographic and quantum chemical studies reveal that fragmentation to give ethylene is promoted by binding of l-arginine in a nonoxidized conformation and of 2-oxoglutarate in an unprecedented high-energy conformation that favors ethylene, relative to succinate formation.

Delftia tsuruhatensis WGR-UOM-BT1, a novel rhizobacterium with PGPR properties from Rauwolfia serpentina (L.) Benth. ex Kurz also suppresses fungal phytopathogens by producing a new antibiotic-AMTM.

PubMed

Prasannakumar, S P; Gowtham, H G; Hariprasad, P; Shivaprasad, K; Niranjana, S R

2015-11-01

The bacterial strain designated as WGR-UOM-BT1 isolated from rhizosphere of Rauwolfia serpentina exhibited broad-spectrum antifungal activity and also improved early plant growth. Based on morphological, biochemical and 16S rRNA gene sequence analyses, the strain BT1 was identified as Delftia tsuruhatensis (KF727978). Under in vitro conditions, the strain BT1 suppressed the growth of wide range of fungal phytopathogens. Purified antimicrobial metabolite from the strain BT1 was identified as nitrogen-containing heterocyclic compound, 'amino(5-(4-methoxyphenyl)-2-methyl-2-(thiophen-2-yl)-2,3-dihydrofuran-3-yl)methanol' (AMTM), with molecular mass of 340•40 and molecular formula of C17 H19 NO3 S. The strain BT1 was positive for rhizosphere colonization (tomato), IAA production, 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity and phosphate solubilization. Under laboratory and greenhouse conditions, the strain BT1 promoted plant growth and suppressed foliar and root fungal pathogens of tomato. Therefore, antimicrobial and disease protection properties of strain BT1 could serve as an effective biological control candidate against devastating fungal pathogens of vegetable plants. Besides, the production of IAA, P solubilization and ACC deaminase activity enhance its potential as a biofertilizer and may stabilize the plant performance under fluctuating environmental conditions. In this study, we reported that Delftia tsuruhatensis WGR-UOM-BT1 strain has the plant growth promotion activities such as rhizosphere colonization (tomato), IAA production, 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity and phosphate solubilization. This bacterial strain was found producing an antimicrobial nitrogen-containing heterocyclic compound identified as 'amino(5-(4-methoxyphenyl)-2-methyl-2-(thiophen-2-yl)-2,3-dihydrofuran-3-yl)methanol' [C17 H19 NO3 S] (AMTM), which is new to the bacterial world. © 2015 The Society for Applied Microbiology.

Biosynthesis of Ethylene from Methionine in Aminoethoxyvinylglycine-Resistant Avocado Tissue

PubMed Central

Baker, James E.; Anderson, James D.; Adams, Douglas O.; Apelbaum, Akiva; Lieberman, Morris

1982-01-01

This study was conducted to determine if aminoethoxyvinylglycine (AVG) insensitivity in avocado (Persea americana Mill., Lula, Haas, and Bacon) tissue was due to an alternate pathway of ethylene biosynthesis from methionine. AVG, at 0.1 millimolar, had little or no inhibitory effect on either total ethylene production or [14C] ethylene production from [14C]methionine in avocado tissue at various stages of ripening. However, aminoxyacetic acid (AOA), which inhibits 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (the AVG-sensitive enzyme of ethylene biosynthesis), inhibited ethylene production in avocado tissue. Total ethylene production was stimulated, and [14C]ethylene production from [14C]methionine was lowered by treating avocado tissue with 1 millimolar ACC. An inhibitor of methionine adenosyltransferase (EC 2.5.1.6), l-2-amino-4-hexynoic acid (AHA), at 1.5 millimolar, effectively inhibited [14C]ethylene production from [14C]methionine in avocado tissue but had no effect on total ethylene production during a 2-hour incubation. Rates of [14C]AVG uptake by avocado and apple (Malus domestica Borkh., Golden Delicious) tissues were similar, and [14C]AVG was the only radioactive compound in alcohol-soluble fractions of the tissues. Hence, AVG-insensitivity in avocado tissue does not appear to be due to lack of uptake or to metabolism of AVG by avocado tissue. ACC synthase activity in extracts of avocado tissue was strongly inhibited (about 60%) by 10 micromolar AVG. Insensitivity of ethylene production in avocado tissue to AVG may be due to inaccessibility of ACC synthase to AVG. AVG-resistance in the avocado system is, therefore, different from that of early climacteric apple tissue, in which AVG-insensitivity of total ethylene production appears to be due to a high level of endogenous ACC relative to its rate of conversion to ethylene. However, the sensitivity of the avocado system to AOA and AHA, dilution of labeled ethylene production by ACC, and stimulation of total ethylene production by ACC provide evidence for the methionine → SAM → ACC → ethylene pathway in avocado and do not suggest the operation of an alternate pathway. PMID:16662192

Potential of Pseudomonas putida PCI2 for the Protection of Tomato Plants Against Fungal Pathogens.

PubMed

Pastor, Nicolás; Masciarelli, Oscar; Fischer, Sonia; Luna, Virginia; Rovera, Marisa

2016-09-01

Tomato is one of the most economically attractive vegetable crops due to its high yields. Diseases cause significant losses in tomato production worldwide. We carried out Polymerase Chain Reaction studies to detect the presence of genes encoding antifungal compounds in the DNA of Pseudomonas putida strain PCI2. We also used liquid chromatography-electrospray tandem mass spectrometry to detect and quantify the production of compounds that increase the resistance of plants to diseases from culture supernatants of PCI2. In addition, we investigated the presence of 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase in PCI2. Finally, PCI2 was used for inoculation of tomato seeds to study its potential biocontrol activity against Fusarium oxysporum MR193. The obtained results showed that no fragments for the encoding genes of hydrogen cyanide, pyoluteorin, 2,4-diacetylphloroglucinol, pyrrolnitrin, or phenazine-1-carboxylic acid were amplified from the DNA of PCI2. On the other hand, PCI2 produced salicylic acid and jasmonic acid in Luria-Bertani medium and grew in a culture medium containing ACC as the sole nitrogen source. We observed a reduction in disease incidence from 53.33 % in the pathogen control to 30 % in tomato plants pre-inoculated with PCI2 as well as increases in shoot and root dry weights in inoculated plants, as compared to the pathogenicity control. This study suggests that inoculation of tomato seeds with P. putida PCI2 increases the resistance of plants to root rot caused by F. oxysporum and that PCI2 produces compounds that may be involved at different levels in increasing such resistance. Thus, PCI2 could represent a non-contaminating management strategy potentially applicable in vegetable crops such as tomato.

Effects of abscisic acid on ethylene biosynthesis and perception in Hibiscus rosa-sinensis L. flower development

PubMed Central

Trivellini, Alice; Ferrante, Antonio; Vernieri, Paolo; Serra, Giovanni

2011-01-01

The effect of the complex relationship between ethylene and abscisic acid (ABA) on flower development and senescence in Hibiscus rosa-sinensis L. was investigated. Ethylene biosynthetic (HrsACS and HrsACO) and receptor (HrsETR and HrsERS) genes were isolated and their expression evaluated in three different floral tissues (petals, style–stigma plus stamens, and ovaries) of detached buds and open flowers. This was achieved through treatment with 0.1 mM 1-aminocyclopropane-1-carboxylic acid (ACC) solution, 500 nl l−1 methylcyclopropene (1-MCP), and 0.1 mM ABA solution. Treatment with ACC and 1-MCP confirmed that flower senescence in hibiscus is ethylene dependent, and treatment with exogenous ABA suggested that ABA may play a role in this process. The 1-MCP impeded petal in-rolling and decreased ABA content in detached open flowers after 9 h. This was preceded by an earlier and sequential increase in ABA content in 1-MCP-treated petals and style–stigma plus stamens between 1 h and 6 h. ACC treatment markedly accelerated flower senescence and increased ethylene production after 6 h and 9 h, particularly in style–stigma plus stamens. Ethylene evolution was positively correlated in these floral tissues with the induction of the gene expression of ethylene biosynthetic and receptor genes. Finally, ABA negatively affected the ethylene biosynthetic pathway and tissue sensitivity in all flower tissues. Transcript abundance of HrsACS, HrsACO, HrsETR, and HrsERS was reduced by exogenous ABA treatment. This research underlines the regulatory effect of ABA on the ethylene biosynthetic and perception machinery at a physiological and molecular level when inhibitors or promoters of senescence are exogenously applied. PMID:21841180

Characterization of Cu(II)-reconstituted ACC Oxidase using experimental and theoretical approaches.

PubMed

El Bakkali-Tahéri, Nadia; Tachon, Sybille; Orio, Maylis; Bertaina, Sylvain; Martinho, Marlène; Robert, Viviane; Réglier, Marius; Tron, Thierry; Dorlet, Pierre; Simaan, A Jalila

2017-06-01

1-Aminocyclopropane-1-carboxylic acid oxidase (ACCO) is a non heme iron(II) containing enzyme that catalyzes the final step of the ethylene biosynthesis in plants. The iron(II) ion is bound in a facial triad composed of two histidines and one aspartate (H177, D179 and H234). Several active site variants were generated to provide alternate binding motifs and the enzymes were reconstituted with copper(II). Continuous wave (cw) and pulsed Electron Paramagnetic Resonance (EPR) spectroscopies as well as Density Functional Theory (DFT) calculations were performed and models for the copper(II) binding sites were deduced. In all investigated enzymes, the copper ion is equatorially coordinated by the two histidine residues (H177 and H234) and probably two water molecules. The copper-containing enzymes are inactive, even when hydrogen peroxide is used in peroxide shunt approach. EPR experiments and DFT calculations were undertaken to investigate substrate's (ACC) binding on the copper ion and the results were used to rationalize the lack of copper-mediated activity. Copyright © 2017 Elsevier Inc. All rights reserved.

Endogenous hormones response to cytokinins with regard to organogenesis in explants of peach (Prunus persica L. Batsch) cultivars and rootstocks (P. persica × Prunus dulcis).

PubMed

Pérez-Jiménez, Margarita; Cantero-Navarro, Elena; Pérez-Alfocea, Francisco; Cos-Terrer, José

2014-11-01

Organogenesis in peach (Prunus persica L. Batsch) and peach rootstocks (P. persica × Prunus dulcis) has been achieved and the action of the regeneration medium on 7 phytohormones, zeatin (Z), zeatin riboside (ZR), indole-3-acetic acid (IAA), abscisic acid (ABA), ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), salicylic acid (SA), and jasmonic acid (JA), has been studied using High performance liquid chromatography - mass spectrometry (HPLC-MS/MS). Three scion peach cultivars, 'UFO-3', 'Flariba' and 'Alice Bigi', and the peach × almond rootstocks 'Garnem' and 'GF677' were cultured in two different media, Murashige and Skoog supplemented with plant growth regulators (PGRs) (regeneration medium) and without PGRs (control medium), in order to study the effects of the media and/or genotypes in the endogenous hormones content and their role in organogenesis. The highest regeneration rate was obtained with the peach × almond rootstocks and showed a lower content of Z, IAA, ABA, ACC and JA. Only Z, ZR and IAA were affected by the action of the culture media. This study shows which hormones are external PGRs-dependent and what is the weight of the genotype and hormones in peach organogenesis that provide an avenue to manipulate in vitro organogenesis in peach. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Differential expression of ethylene biosynthesis genes in drupelets and receptacle of raspberry (Rubus idaeus).

PubMed

Fuentes, Lida; Monsalve, Liliam; Morales-Quintana, Luis; Valdenegro, Mónika; Martínez, Juan-Pablo; Defilippi, Bruno G; González-Agüero, Mauricio

2015-05-01

Red Raspberry (Rubus idaeus) is traditionally classified as non-climacteric, and the role of ethylene in fruit ripening is not clear. The available information indicates that the receptacle, a modified stem that supports the drupelets, is involved in ethylene production of ripe fruits. In this study, we report receptacle-related ethylene biosynthesis during the ripening of fruits of cv. Heritage. In addition, the expression pattern of ethylene biosynthesis transcripts was evaluated during the ripening process. The major transcript levels of 1-aminocyclopropane-1-carboxylic acid synthase (RiACS1) and 1-aminocyclopropane-1-carboxylic acid oxidase (RiACO1) were concomitant with ethylene production, increased total soluble solids (TSS) and decreased titratable acidity (TA) and fruit firmness. Moreover, ethylene biosynthesis and transcript levels of RiACS1 and RiACO1 were higher in the receptacle, sustaining the receptacle's role as a source of ethylene in regulating the ripening of raspberry. Copyright © 2015 Elsevier GmbH. All rights reserved.

Ethylene-dependent aerenchyma formation in adventitious roots is regulated differently in rice and maize.

PubMed

Yamauchi, Takaki; Tanaka, Akihiro; Mori, Hitoshi; Takamure, Itsuro; Kato, Kiyoaki; Nakazono, Mikio

2016-10-01

In roots of gramineous plants, lysigenous aerenchyma is created by the death and lysis of cortical cells. Rice (Oryza sativa) constitutively forms aerenchyma under aerobic conditions, and its formation is further induced under oxygen-deficient conditions. However, maize (Zea mays) develops aerenchyma only under oxygen-deficient conditions. Ethylene is involved in lysigenous aerenchyma formation. Here, we investigated how ethylene-dependent aerenchyma formation is differently regulated between rice and maize. For this purpose, in rice, we used the reduced culm number1 (rcn1) mutant, in which ethylene biosynthesis is suppressed. Ethylene is converted from 1-aminocyclopropane-1-carboxylic acid (ACC) by the action of ACC oxidase (ACO). We found that OsACO5 was highly expressed in the wild type, but not in rcn1, under aerobic conditions, suggesting that OsACO5 contributes to aerenchyma formation in aerated rice roots. By contrast, the ACO genes in maize roots were weakly expressed under aerobic conditions, and thus ACC treatment did not effectively induce ethylene production or aerenchyma formation, unlike in rice. Aerenchyma formation in rice roots after the initiation of oxygen-deficient conditions was faster and greater than that in maize. These results suggest that the difference in aerenchyma formation in rice and maize is due to their different mechanisms for regulating ethylene biosynthesis. © 2016 John Wiley & Sons Ltd.

Red light regulation of ethylene biosynthesis and gravitropism in etiolated pea stems

NASA Technical Reports Server (NTRS)

Steed, C. L.; Taylor, L. K.; Harrison, M. A.

2004-01-01

During gravitropism, the accumulation of auxin in the lower side of the stem causes increased growth and the subsequent curvature, while the gaseous hormone ethylene plays a modulating role in regulating the kinetics of growth asymmetries. Light also contributes to the control of gravitropic curvature, potentially through its interaction with ethylene biosynthesis. In this study, red-light pulse treatment of etiolated pea epicotyls was evaluated for its effect on ethylene biosynthesis during gravitropic curvature. Ethylene biosynthesis analysis included measurements of ethylene; the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC); malonyl-conjugated ACC (MACC); and expression levels of pea ACC oxidase (Ps-ACO1) and ACC synthase (Ps-ACS1, Ps-ACS2) genes by reverse transcriptase-polymerase chain reaction analysis. Red-pulsed seedlings were given a 6 min pulse of 11 micromoles m-2 s-1 red-light 15 h prior to horizontal reorientation for consistency with the timeline of red-light inhibition of ethylene production. Red-pulse treatment significantly reduced ethylene production and MACC levels in epicotyl tissue. However, there was no effect of red-pulse treatment on ACC level, or expression of ACS or ACO genes. During gravitropic curvature, ethylene production increased from 60 to 120 min after horizontal placement in both control and red-pulsed epicotyls. In red-pulsed tissues, ACC levels increased by 120 min after horizontal reorientation, accompanied by decreased MACC levels in the lower portion of the epicotyl. Overall, our results demonstrate that ethylene production in etiolated epicotyls increases after the initiation of curvature. This ethylene increase may inhibit cell growth in the lower portion of the epicotyl and contribute to tip straightening and reduced overall curvature observed after the initial 60 min of curvature in etiolated pea epicotyls.

Use of bacterial acc deaminase to increase oil (especially poly aromatic hydrocarbons) phytoremediation efficiency for maize (zea mays) seedlings.

PubMed

Rezvani Borujeni, Samira; Khavazi, Kazem; Asgharzadeh, Ahmad; Rezvani Borujeni, Iraj

2018-04-16

Oil presence in soil, as a stressor, reduces phytoremediation efficiency through an increase in the plant stress ethylene. Bacterial 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, as a plant stress ethylene reducer, was employed to increase oil phytoremediation efficiency. For this purpose, the ability of ACC deaminase-producing Pseudomonas strains to grow in oil-polluted culture media and withstand various concentrations of oil and also their ability to reduce plant stress ethylene and enhance some growth characteristics of maize and finally their effects on increasing phytoremediation efficiency of poly aromatic hydrocarbons (PAHs) in soil were investigated. Based on the results, of tested strains just P9 and P12 were able to perform oil degradation. Increasing oil concentration from 0 to 10% augmented these two strains population, 15.7% and 12.9%, respectively. The maximum increase in maize growth was observed in presence of P12 strain. Results of high-performance liquid chromatography (HPLC) revealed that PAHs phytoremediation efficiency was higher for inoculated seeds than uninoculated. The highest plant growth and PAHs removal percentage (74.9%) from oil-polluted soil was observed in maize inoculated with P12. These results indicate the significance of ACC deaminase producing bacteria in alleviation of plant stress ethylene in oil-polluted soils and increasing phytoremediation efficiency of such soils.

Altered cultivar resistance of kimchi cabbage seedlings mediated by salicylic Acid, jasmonic Acid and ethylene.

PubMed

Lee, Young Hee; Kim, Sang Hee; Yun, Byung-Wook; Hong, Jeum Kyu

2014-09-01

Two cultivars Buram-3-ho (susceptible) and CR-Hagwang (moderate resistant) of kimchi cabbage seedlings showed differential defense responses to anthracnose (Colletotrichum higginsianum), black spot (Alternaria brassicicola) and black rot (Xanthomonas campestris pv. campestris, Xcc) diseases in our previous study. Defense-related hormones salicylic acid (SA), jasmonic acid (JA) and ethylene led to different transcriptional regulation of pathogenesis-related (PR) gene expression in both cultivars. In this study, exogenous application of SA suppressed basal defenses to C. higginsianum in the 1st leaves of the susceptible cultivar and cultivar resistance of the 2nd leaves of the resistant cultivar. SA also enhanced susceptibility of the susceptible cultivar to A. brassicicola. By contrast, SA elevated disease resistance to Xcc in the resistant cultivar, but not in the susceptible cultivar. Methyl jasmonate (MJ) treatment did not affect the disease resistance to C. higginsianum and Xcc in either cultivar, but it compromised the disease resistance to A. brassicicola in the resistant cultivar. Treatment with 1-aminocyclopropane-1-carboxylic acid (ACC) ethylene precursor did not change resistance of the either cultivar to C. higginsianum and Xcc. Effect of ACC pretreatment on the resistance to A. brassicicola was not distinguished between susceptible and resistant cultivars, because cultivar resistance of the resistant cultivar was lost by prolonged moist dark conditions. Taken together, exogenously applied SA, JA and ethylene altered defense signaling crosstalk to three diseases of anthracnose, black spot and black rot in a cultivar-dependent manner.

The influence of abscisic acid on the ethylene biosynthesis pathway in the functioning of the flower abscission zone in Lupinus luteus.

PubMed

Wilmowicz, Emilia; Frankowski, Kamil; Kućko, Agata; Świdziński, Michał; de Dios Alché, Juan; Nowakowska, Anna; Kopcewicz, Jan

2016-11-01

Flower abscission is a highly regulated developmental process activated in response to exogenous (e.g. changing environmental conditions) and endogenous stimuli (e.g. phytohormones). Ethylene (ET) and abscisic acid (ABA) are very effective stimulators of flower abortion in Lupinus luteus, which is a widely cultivated species in Poland, Australia and Mediterranean countries. In this paper, we show that artificial activation of abscission by flower removal caused an accumulation of ABA in the abscission zone (AZ). Moreover, the blocking of that phytohormone's biosynthesis by NDGA (nordihydroguaiaretic acid) decreased the number of abscised flowers. However, the application of NBD - an inhibitor of ET action - reversed the stimulatory effect of ABA on flower abscission, indicating that ABA itself is not sufficient to turn on the organ separation. Our analysis revealed that exogenous ABA significantly accelerated the transcriptional activity of the ET biosynthesis genes ACC synthase (LlACS) and oxidase (LlACO), and moreover, strongly increased the level of 1-aminocyclopropane-1-carboxylic acid (ACC) - ET precursor, which was specifically localized within AZ cells. We cannot exclude the possibility that ABA mediates flower abscission processes by enhancing the ET biosynthesis rate. The findings of our study will contribute to the overall basic knowledge on the phytohormone-regulated generative organs abscission in L. luteus. Copyright © 2016 Elsevier GmbH. All rights reserved.

Auxin-Induced Ethylene Triggers Abscisic Acid Biosynthesis and Growth Inhibition1

PubMed Central

Hansen, Hauke; Grossmann, Klaus

2000-01-01

The growth-inhibiting effects of indole-3-acetic acid (IAA) at high concentration and the synthetic auxins 7-chloro-3-methyl-8-quinolinecarboxylic acid (quinmerac), 2-methoxy-3,6-dichlorobenzoic acid (dicamba), 4-amino-3,6,6-trichloropicolinic acid (picloram), and naphthalene acetic acid, were investigated in cleavers (Galium aparine). When plants were root treated with 0.5 mm IAA, shoot epinasty and inhibition of root and shoot growth developed during 24 h. Concomitantly, 1-aminocyclopropane-1-carboxylic acid (ACC) synthase activity, and ACC and ethylene production were transiently stimulated in the shoot tissue within 2 h, followed by increases in immunoreactive (+)-abscisic acid (ABA) and its precursor xanthoxal (xanthoxin) after 5 h. After 24 h of treatment, levels of xanthoxal and ABA were elevated up to 2- and 24-fold, relative to control, respectively. In plants treated with IAA, 7-chloro-3-methyl-8-quinolinecarboxylic acid, naphthalene acetic acid, 2-methoxy-3,6-dichlorobenzoic acid, and 4-amino-3,6,6-trichloropicolinic acid, levels of ethylene, ACC, and ABA increased in close correlation with inhibition of shoot growth. Aminoethoxyvinyl-glycine and cobalt ions, which inhibit ethylene synthesis, decreased ABA accumulation and growth inhibition, whereas the ethylene-releasing ethephon promoted ABA levels and growth inhibition. In accordance, tomato mutants defective in ethylene perception (never ripe) did not produce the xanthoxal and ABA increases and growth inhibition induced by auxins in wild-type plants. This suggests that auxin-stimulated ethylene triggers ABA accumulation and the consequent growth inhibition. Reduced catabolism most probably did not contribute to ABA increase, as indicated by immunoanalyses of ABA degradation and conjugation products in shoot tissue and by pulse experiments with [3H]-ABA in cell suspensions of G. aparine. In contrast, studies using inhibitors of ABA biosynthesis (fluridone, naproxen, and tungstate), ABA-deficient tomato mutants (notabilis, flacca, and sitiens), and quantification of xanthophylls indicate that ABA biosynthesis is influenced, probably through stimulated cleavage of xanthophylls to xanthoxal in shoot tissue. PMID:11080318

Phytohormone profile in Lactuca sativa and Brassica oleracea plants grown under Zn deficiency.

PubMed

Navarro-León, Eloy; Albacete, Alfonso; Torre-González, Alejandro de la; Ruiz, Juan M; Blasco, Begoña

2016-10-01

Phytohormones, structurally diverse compounds, are involved in multiple processes within plants, such as controlling plant growth and stress response. Zn is an essential micronutrient for plants and its deficiency causes large economic losses in crops. Therefore, the purpose of this study was to analyse the role of phytohormones in the Zn-deficiency response of two economically important species, i.e. Lactuca sativa and Brassica oleracea. For this, these two species were grown hydroponically with different Zn-application rates: 10 μM Zn as control and 0.1 μM Zn as deficiency treatment and phytohormone concentration was determined by U-HPLC-MS. Zn deficiency resulted in a substantial loss of biomass in L. sativa plants that was correlated with a decline in growth-promoting hormones such as indole-3-acetic acid (IAA), cytokinins (CKs), and gibberellins (GAs). However these hormones increased or stabilized their concentrations in B. oleracea and could help to maintain the biomass in this species. A lower concentration of stress-signaling hormones such as ethylene precursor aminocyclopropane-1-carboxylic acid (ACC), abscisic acid (ABA), salicylic acid (SA) and jasmonic acid (JA) and also CKs might be involved in Zn uptake in L. sativa while a rise in GA4, isopentenyl adenine (iP), and ACC and a fall in JA and SA might contribute to a better Zn-utilization efficiency (ZnUtE), as observed in B. oleracea plants. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of plant growth-promoting bacteria isolated from copper tailings on plants in sterilized and non-sterilized tailings.

PubMed

Liu, Weiqiu; Yang, Chao; Shi, Si; Shu, Wensheng

2014-02-01

Ten strains of Cu-tolerant bacteria with potential plant growth-promoting ability were isolated by selecting strains with the ability to use 1-aminocyclopropane-1-carboxylate as a sole nitrogen source (designated ACC-B) or fix nitrogen (designated FLN-B) originating from the rhizosphere of plants growing on copper tailings. All 10 strains proved to have intrinsic ability to produce indole acetic acid and siderophores, and most of them could mobilize insoluble phosphate. In addition, a greenhouse study showed that ACC-B, FLN-B and a mixture of both had similar, potent ability to stimulate growth of Pennisetum purpureum, Medicago sativa and Oenothera erythrosepala plants grown on sterilized tailings. For instance, above-ground biomass of P. purpureum was 278-357% greater after 60d growth on sterilized tailings in their presence. They could also significantly promote the growth of the plants grown on non-sterilized tailings, though the growth-promoting effects were much weaker. So, strategies for using of the plant growth-promoting bacteria in the practice of phytoremediation deserve further studies to get higher growth-promoting efficiency. Copyright © 2013 Elsevier Ltd. All rights reserved.

Isolation and Molecular Characterization of 1-Aminocyclopropane-1-carboxylic Acid Synthase Genes in Hevea brasiliensis

PubMed Central

Zhu, Jia-Hong; Xu, Jing; Chang, Wen-Jun; Zhang, Zhi-Li

2015-01-01

Ethylene is an important factor that stimulates Hevea brasiliensis to produce natural rubber. 1-Aminocyclopropane-1-carboxylic acid synthase (ACS) is a rate-limiting enzyme in ethylene biosynthesis. However, knowledge of the ACS gene family of H. brasiliensis is limited. In this study, nine ACS-like genes were identified in H. brasiliensis. Sequence and phylogenetic analysis results confirmed that seven isozymes (HbACS1–7) of these nine ACS-like genes were similar to ACS isozymes with ACS activity in other plants. Expression analysis results showed that seven ACS genes were differentially expressed in roots, barks, flowers, and leaves of H. brasiliensis. However, no or low ACS gene expression was detected in the latex of H. brasiliensis. Moreover, seven genes were differentially up-regulated by ethylene treatment.These results provided relevant information to help determine the functions of the ACS gene in H. brasiliensis, particularly the functions in regulating ethylene stimulation of latex production. PMID:25690030

Nitric oxide acts upstream of ethylene in cell wall phosphorus reutilization in phosphorus-deficient rice.

PubMed

Zhu, Xiao Fang; Zhu, Chun Quan; Wang, Chao; Dong, Xiao Ying; Shen, Ren Fang

2017-01-01

Nitric oxide (NO) and ethylene are both involved in cell wall phosphorus (P) reutilization in P-deficient rice; however, the crosstalk between them remains unclear. In the present study using P-deficient 'Nipponbare' (Nip), root NO accumulation significantly increased after 1 h and reached a maximum at 3 h, while ethylene production significantly increased after 3 h and reached a maximum at 6 h, indicating NO responded more quickly than ethylene. Irrespective of P status, addition of the NO donor sodium nitroprusside (SNP) significantly increased while the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO) significantly decreased the production of ethylene, while neither the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) nor the ethylene inhibitor aminoethoxyvinylglycine (AVG) had any influence on NO accumulation, suggesting NO acted upstream of ethylene. Under P-deficient conditions, SNP and ACC alone significantly increased root soluble P content through increasing pectin content, and c-PTIO addition to the ACC treatment still showed the same tendency; however, AVG+SNP treatment had no effect, further indicating that ethylene was the downstream signal affecting pectin content. The expression of the phosphate transporter gene OsPT2 showed the same tendency as the NO-ethylene-pectin pathway. Taken together, we conclude that ethylene functions downstream of NO in cell wall P reutilization in P-deficient rice. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Auxin-induced ethylene triggers abscisic acid biosynthesis and growth inhibition.

PubMed

Hansen, H; Grossmann, K

2000-11-01

The growth-inhibiting effects of indole-3-acetic acid (IAA) at high concentration and the synthetic auxins 7-chloro-3-methyl-8-quinolinecarboxylic acid (quinmerac), 2-methoxy-3,6-dichlorobenzoic acid (dicamba), 4-amino-3,6, 6-trichloropicolinic acid (picloram), and naphthalene acetic acid, were investigated in cleavers (Galium aparine). When plants were root treated with 0.5 mM IAA, shoot epinasty and inhibition of root and shoot growth developed during 24 h. Concomitantly, 1-aminocyclopropane-1-carboxylic acid (ACC) synthase activity, and ACC and ethylene production were transiently stimulated in the shoot tissue within 2 h, followed by increases in immunoreactive (+)-abscisic acid (ABA) and its precursor xanthoxal (xanthoxin) after 5 h. After 24 h of treatment, levels of xanthoxal and ABA were elevated up to 2- and 24-fold, relative to control, respectively. In plants treated with IAA, 7-chloro-3-methyl-8-quinolinecarboxylic acid, naphthalene acetic acid, 2-methoxy-3,6-dichlorobenzoic acid, and 4-amino-3,6,6-trichloropicolinic acid, levels of ethylene, ACC, and ABA increased in close correlation with inhibition of shoot growth. Aminoethoxyvinyl-glycine and cobalt ions, which inhibit ethylene synthesis, decreased ABA accumulation and growth inhibition, whereas the ethylene-releasing ethephon promoted ABA levels and growth inhibition. In accordance, tomato mutants defective in ethylene perception (never ripe) did not produce the xanthoxal and ABA increases and growth inhibition induced by auxins in wild-type plants. This suggests that auxin-stimulated ethylene triggers ABA accumulation and the consequent growth inhibition. Reduced catabolism most probably did not contribute to ABA increase, as indicated by immunoanalyses of ABA degradation and conjugation products in shoot tissue and by pulse experiments with [(3)H]-ABA in cell suspensions of G. aparine. In contrast, studies using inhibitors of ABA biosynthesis (fluridone, naproxen, and tungstate), ABA-deficient tomato mutants (notabilis, flacca, and sitiens), and quantification of xanthophylls indicate that ABA biosynthesis is influenced, probably through stimulated cleavage of xanthophylls to xanthoxal in shoot tissue.

Characterization of Mn-resistant endophytic bacteria from Mn-hyperaccumulator Phytolacca americana and their impact on Mn accumulation of hybrid penisetum.

PubMed

Zhang, Wen-Hui; Chen, Wei; He, Lin-Yan; Wang, Qi; Sheng, Xia-Fang

2015-10-01

Three hundred Mn-resistant endophytic bacteria were isolated from the Mn-hyperaccumulator, Phytolacca americana, grown at different levels of Mn (0, 1, and 10mM) stress. Under no Mn stress, 90%, 92%, and 11% of the bacteria produced indole acetic acid (IAA), siderophore, and 1-aminocyclopropane-1-carboxylate (ACC) deaminase, respectively. Under Mn stress, 68-94%, 91-92%, and 21-81% of the bacteria produced IAA, siderophore, and ACC deaminase, respectively. Greater percentages of ACC deaminase-producing bacteria were found in the Mn-treated P. americana. Furthermore, the ratios of IAA- and siderophore-producing bacteria were significantly higher in the Mn treated plant leaves, while the ratio of ACC deaminase-producing bacteria was significantly higher in the Mn treated-roots. Based on 16S rRNA gene sequence analysis, Mn-resistant bacteria were affiliated with 10 genera. In experiments involving hybrid penisetum grown in soils treated with 0 and 1000mgkg(-1) of Mn, inoculation with strain 1Y31 was found to increase the root (ranging from 6.4% to 18.3%) and above-ground tissue (ranging from 19.3% to 70.2%) mass and total Mn uptake of above-ground tissues (64%) compared to the control. Furthermore, inoculation with strain 1Y31 was found to increase the ratio of IAA-producing bacteria in the rhizosphere and bulk soils of hybrid penisetum grown in Mn-added soils. The results showed the effect of Mn stress on the ratio of the plant growth-promoting factor-producing endophytic bacteria of P. americana and highlighted the potential of endophytic bacterium as an inoculum for enhanced phytoremediation of Mn-polluted soils by hybrid penisetum plants. Copyright © 2015 Elsevier Inc. All rights reserved.

Ethylene sensitivity and relative air humidity regulate root hydraulic properties in tomato plants.

PubMed

Calvo-Polanco, Monica; Ibort, Pablo; Molina, Sonia; Ruiz-Lozano, Juan Manuel; Zamarreño, Angel María; García-Mina, Jose María; Aroca, Ricardo

2017-11-01

The effect of ethylene and its precursor ACC on root hydraulic properties, including aquaporin expression and abundance, is modulated by relative air humidity and plant sensitivity to ethylene. Relative air humidity (RH) is a main factor contributing to water balance in plants. Ethylene (ET) is known to be involved in the regulation of root water uptake and stomatal opening although its role on plant water balance under different RH is not very well understood. We studied, at the physiological, hormonal and molecular levels (aquaporins expression, abundance and phosphorylation state), the plant responses to exogenous 1-aminocyclopropane-1-carboxylic acid (ACC; precursor of ET) and 2-aminoisobutyric acid (AIB; inhibitor of ET biosynthesis), after 24 h of application to the roots of tomato wild type (WT) plants and its ET-insensitive never ripe (nr) mutant, at two RH levels: regular (50%) and close to saturation RH. Highest RH induced an increase of root hydraulic conductivity (Lp o ) of non-treated WT plants, and the opposite effect in nr mutants. The treatment with ACC reduced Lp o in WT plants at low RH and in nr plants at high RH. The application of AIB increased Lp o only in nr plants at high RH. In untreated plants, the RH treatment changed the abundance and phosphorylation of aquaporins that affected differently both genotypes according to their ET sensitivity. We show that RH is critical in regulating root hydraulic properties, and that Lp o is affected by the plant sensitivity to ET, and possibly to ACC, by regulating aquaporins expression and their phosphorylation status. These results incorporate the relationship between RH and ET in the response of Lp o to environmental changes.

Rhizobitoxine-induced Chlorosis Occurs in Coincidence with Methionine Deficiency in Soybeans

PubMed Central

Okazaki, Shin; Sugawara, Masayuki; Yuhashi, Ken-Ichi; Minamisawa, Kiwamu

2007-01-01

Background and Aims Rhizobitoxine, produced by the legume symbiont Bradyrhizobium elkanii, inhibits cystathionine-β-lyase (EC 4·4·1·8) in methionine biosynthesis and 1-aminocyclopropane-1-carboxylate synthase (ACC) in ethylene biosynthesis. Rhizobitoxine production by B. elkanii enhances nodulation of host legumes via the inhibition of ethylene synthesis, but causes foliar chlorosis in susceptible soybeans, though how it does so remains to be investigated. The aim of this study was to examine the physiological basis of rhizobitoxine-induced chlorosis in soybeans. Methods Wild-type B. elkanii and a rhizobitoxine-deficient mutant were inoculated in Glycine max ‘Lee’. Thirty days after inoculation, the upper parts of soybean shoots were analysed for amino acid contents. Chlorotic soybeans inoculated with wild-type B. elkanii were treated with methionine and ACC to assess the effects of the chemicals on the chlorosis. Key Results Chlorotic upper shoots of soybeans inoculated with wild-type B. elkanii had a lower methionine content and higher accumulation of the methionine precursors than those with the rhizobitoxine-deficient mutant. In addition, the foliar chlorosis was alleviated by the application of methionine. Conclusions Rhizobitoxine-induced chlorosis occurs in coincidence with methionine deficiency as a result of cystathione-β-lyase inhibition during methionine biosynthesis. PMID:17525098

Cadmium-induced ethylene production and responses in Arabidopsis thaliana rely on ACS2 and ACS6 gene expression

PubMed Central

2014-01-01

Background Anthropogenic activities cause metal pollution worldwide. Plants can absorb and accumulate these metals through their root system, inducing stress as a result of excess metal concentrations inside the plant. Ethylene is a regulator of multiple plant processes, and is affected by many biotic and abiotic stresses. Increased ethylene levels have been observed after exposure to excess metals but it remains unclear how the increased ethylene levels are achieved at the molecular level. In this study, the effects of cadmium (Cd) exposure on the production of ethylene and its precursor 1-aminocyclopropane-1-carboxylic acid (ACC), and on the expression of the ACC Synthase (ACS) and ACC Oxidase (ACO) multigene families were investigated in Arabidopsis thaliana. Results Increased ethylene release after Cd exposure was directly measurable in a system using rockwool-cultivated plants; enhanced levels of the ethylene precursor ACC together with higher mRNA levels of ethylene responsive genes: ACO2, ETR2 and ERF1 also indicated increased ethylene production in hydroponic culture. Regarding underlying mechanisms, it was found that the transcript levels of ACO2 and ACO4, the most abundantly expressed members of the ACO multigene family, were increased upon Cd exposure. ACC synthesis is the rate-limiting step in ethylene biosynthesis, and transcript levels of both ACS2 and ACS6 showed the highest increase and became the most abundant isoforms after Cd exposure, suggesting their importance in the Cd-induced increase of ethylene production. Conclusions Cadmium induced the biosynthesis of ACC and ethylene in Arabidopsis thaliana plants mainly via the increased expression of ACS2 and ACS6. This was confirmed in the acs2-1acs6-1 double knockout mutants, which showed a decreased ethylene production, positively affecting leaf biomass and resulting in a delayed induction of ethylene responsive gene expressions without significant differences in Cd contents between wild-type and mutant plants. PMID:25082369

The rhizobacterium Variovorax paradoxus 5C-2, containing ACC deaminase, promotes growth and development of Arabidopsis thaliana via an ethylene-dependent pathway

PubMed Central

Dodd, Ian C.

2013-01-01

Many plant-growth-promoting rhizobacteria (PGPR) associated with plant roots contain the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase and can metabolize ACC, the immediate precursor of the plant hormone ethylene, thereby decreasing plant ethylene production and increasing plant growth. However, relatively few studies have explicitly linked ethylene emission and/or action to growth promotion in these plant–microbe interactions. This study examined effects of the PGPR Variovorax paradoxus 5C-2 containing ACC deaminase on the growth and development of Arabidopsis thaliana using wild-type (WT) plants and several ethylene-related mutants (etr1-1, ein2-1, and eto1-1). Soil inoculation with V. paradoxus 5C-2 promoted growth (leaf area and shoot biomass) of WT plants and the ethylene-overproducing mutant eto1-1, and also enhanced floral initiation of WT plants by 2.5 days. However, these effects were not seen in ethylene-insensitive mutants (etr1-1 and ein2-1) even though bacterial colonization of the root system was similar. Furthermore, V. paradoxus 5C-2 decreased ACC concentrations of rosette leaves of WT plants by 59% and foliar ethylene emission of both WT plants and eto1-1 mutants by 42 and 37%, respectively. Taken together, these results demonstrate that a fully functional ethylene signal transduction pathway is required for V. paradoxus 5C-2 to stimulate leaf growth and flowering of A. thaliana. PMID:23404897

The rhizobacterium Variovorax paradoxus 5C-2, containing ACC deaminase, promotes growth and development of Arabidopsis thaliana via an ethylene-dependent pathway.

PubMed

Chen, Lin; Dodd, Ian C; Theobald, Julian C; Belimov, Andrey A; Davies, William J

2013-04-01

Many plant-growth-promoting rhizobacteria (PGPR) associated with plant roots contain the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase and can metabolize ACC, the immediate precursor of the plant hormone ethylene, thereby decreasing plant ethylene production and increasing plant growth. However, relatively few studies have explicitly linked ethylene emission and/or action to growth promotion in these plant-microbe interactions. This study examined effects of the PGPR Variovorax paradoxus 5C-2 containing ACC deaminase on the growth and development of Arabidopsis thaliana using wild-type (WT) plants and several ethylene-related mutants (etr1-1, ein2-1, and eto1-1). Soil inoculation with V. paradoxus 5C-2 promoted growth (leaf area and shoot biomass) of WT plants and the ethylene-overproducing mutant eto1-1, and also enhanced floral initiation of WT plants by 2.5 days. However, these effects were not seen in ethylene-insensitive mutants (etr1-1 and ein2-1) even though bacterial colonization of the root system was similar. Furthermore, V. paradoxus 5C-2 decreased ACC concentrations of rosette leaves of WT plants by 59% and foliar ethylene emission of both WT plants and eto1-1 mutants by 42 and 37%, respectively. Taken together, these results demonstrate that a fully functional ethylene signal transduction pathway is required for V. paradoxus 5C-2 to stimulate leaf growth and flowering of A. thaliana.

Inhibitors of Ethylene Biosynthesis and Signaling.

PubMed

Schaller, G Eric; Binder, Brad M

2017-01-01

Ethylene is a gas biosynthesized by plants which has many physiological and developmental effects on their growth. Ethylene affects agriculturally and horticulturally important traits such as fruit ripening, post-harvest physiology, senescence, and abscission, and so ethylene action is often inhibited to improve the shelf life of fruits, vegetables, and cut flowers. Chemical inhibitors of ethylene action are also useful for research to characterize the mechanisms of ethylene biosynthesis and signal transduction, and the role that ethylene plays in various physiological processes. Here, we describe the use of three inhibitors commonly used for the study of ethylene action in plants: 2-aminoethoxyvinyl glycine (AVG), silver ions (Ag), and the gaseous compound 1-methylcyclopropene (1-MCP). AVG is an inhibitor of 1-aminocyclopropane-1-carboxylic acid (ACC) synthase, a key enzyme involved in ethylene biosynthesis. Silver and 1-MCP are both inhibitors of the ethylene receptors. Inhibitor use as well as off-target effects are described with a focus on ethylene responses in dark-grown Arabidopsis seedlings. Methods for the use of these inhibitors can be applied to other plant growth assays.

Differential feedback regulation of ethylene biosynthesis in pulp and peel tissues of banana fruit.

PubMed

Inaba, Akitsugu; Liu, Xuejun; Yokotani, Naoki; Yamane, Miki; Lu, Wang-Jin; Nakano, Ryohei; Kubo, Yasutaka

2007-01-01

The feedback regulation of ethylene biosynthesis in banana [Musa sp. (AAA group, Cavendish subgroup) cv. Grand Nain] fruit was investigated in an attempt to clarify the opposite effect of 1-methylcyclopropene (1-MCP), an ethylene action inhibitor, before and after the onset of ripening. 1-MCP pre-treatment completely prevented the ripening-induced effect of propylene in pre-climacteric banana fruit, whereas treatment after the onset of ripening stimulated ethylene production. In pre-climacteric fruit, higher concentrations of propylene suppressed ethylene production more strongly, despite their earlier ethylene-inducing effect. Exposure of the fruit ripened by propylene to 1-MCP increased ethylene production concomitantly with an increase in 1-aminocyclopropane-1-carboxylate (ACC) synthase activity and ACC content, and prevented a transient decrease in MA-ACS1 transcripts in the pulp tissues. In contrast, in the peel of ripening fruit, 1-MCP prevented the increase in ethylene production and subsequently the ripening process by reduction of the increase in MA-ACS1 and MA-ACO1 transcripts and of ACC synthase and ACC oxidase activities. These results suggest that ethylene biosynthesis in ripening banana fruit may be controlled negatively in the pulp tissue and positively in the peel tissue. This differential regulation by ethylene in pulp and peel tissues was also observed for MA-PL, MA-Exp, and MA-MADS genes.

A recessive mutation in the RUB1-conjugating enzyme, RCE1, reveals a requirement for RUB modification for control of ethylene biosynthesis and proper induction of basic chitinase and PDF1.2 in Arabidopsis.

PubMed

Larsen, Paul B; Cancel, Jesse D

2004-05-01

By screening etiolated Arabidopsis seedlings for mutants with aberrant ethylene-related phenotypes, we identified a mutant that displays features of the ethylene-mediated triple response even in the absence of ethylene. Further characterization showed that the phenotype observed for the dark-grown seedlings of this mutant is reversible by prevention of ethylene perception and is dependent on a modest increase in ethylene production correlated with an increase in 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase (ACO) activity in the hypocotyl. Molecular characterization of leaves of the mutant revealed severely impaired induction of basic chitinase (chiB) and plant defensin (PDF)1.2 following treatment with jasmonic acid and/or ethylene. Positional cloning of the mutation resulted in identification of a 49-bp deletion in RCE1 (related to ubiquitin 1 (RUB1)-conjugating enzyme), which has been demonstrated to be responsible for covalent attachment of RUB1 to the SCF (Skpl Cdc 53 F-box) ubiquitin ligase complex to modify its activity. Our analyses with rce1-2 demonstrate a previously unknown requirement for RUB1 modification for regulation of ethylene biosynthesis and proper induction of defense-related genes in Arabidopsis.

Calcium ion dependency of ethylene production in segments of primary roots of Zea mays

NASA Technical Reports Server (NTRS)

Hasenstein, K. H.; Evans, M. L.

1986-01-01

We investigated the effect of Ca2+ on ethylene production in 2-cm long apical segments from primary roots of corn (Zea mays L., B73 x Missouri 17) seedlings. The seedlings were raised under different conditions of Ca2+ availability. Low-Ca and high-Ca seedlings were raised by soaking the grains and watering the seedlings with distilled water or 10 mM CaCl2, respectively. Segments from high-Ca roots produced more than twice as much ethylene as segments from low-Ca roots. Indoleacetic acid (IAA; 1 micromole) enhanced ethylene production in segments from both low-Ca and high-Ca roots but auxin-induced promotion of ethylene production was consistently higher in segments from high-Ca roots. Addition of 1-aminocyclopropane-1-carboxylic acid (ACC) to root segments from low-Ca seedlings doubled total ethylene production and the rate of production remained fairly constant during a 24 h period of monitoring. In segments from high-Ca seedlings ACC also increased total ethylene production but most of the ethylene was produced within the first 6 h. The data suggest that Ca2+ enhances the conversion of ACC to ethylene. The terminal 2 mm of the root tip were found to be especially important to ethylene biosynthesis by apical segments and, experiments using 45Ca2+ as tracer indicated that the apical 2 mm of the root is the region of strongest Ca2+ accumulation. Other cations such as Mn2+, Mg2+, and K+ could largely substitute for Ca2+. The significance of these findings is discussed with respect to recent evidence for gravity-induced Ca2+ redistribution and its relationship to the establishment of asymmetric growth during gravitropic curvature.

Effects of ethylene on photosystem II and antioxidant enzyme activity in Bermuda grass under low temperature.

PubMed

Hu, Zhengrong; Fan, Jibiao; Chen, Ke; Amombo, Erick; Chen, Liang; Fu, Jinmin

2016-04-01

The phytohormone ethylene has been reported to mediate plant response to cold stress. However, it is still debated whether the effect of ethylene on plant response to cold stress is negative or positive. The objective of the present study was to explore the role of ethylene in the cold resistance of Bermuda grass (Cynodon dactylon (L).Pers.). Under control (warm) condition, there was no obvious effect of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) or the antagonist Ag(+) of ethylene signaling on electrolyte leakage (EL) and malondialdehyde (MDA) content. Under cold stress conditions, ACC-treated plant leaves had a greater level of EL and MDA than the untreated leaves. However, the EL and MDA values were lower in the Ag(+) regime versus the untreated. In addition, after 3 days of cold treatment, ACC remarkably reduced the content of soluble protein and also altered antioxidant enzyme activity. Under control (warm) condition, there was no significant effect of ACC on the performance of photosystem II (PS II) as monitored by chlorophyll α fluorescence transients. However, under cold stress, ACC inhibited the performance of PS II. Under cold condition, ACC remarkably reduced the performance index for energy conservation from excitation to the reduction of intersystem electron acceptors (PI(ABS)), the maximum quantum yield of primary photochemistry (φP0), the quantum yield of electron transport flux from Q(A) to Q(B) (φE0), and the efficiency/probability of electron transport (ΨE0). Simultaneously, ACC increased the values of specific energy fluxes for absorption (ABS/RC) and dissipation (DI0/RC) after 3 days of cold treatment. Additionally, under cold condition, exogenous ACC altered the expressions of several related genes implicated in the induction of cold tolerance (LEA, SOD, POD-1 and CBF1, EIN3-1, and EIN3-2). The present study thus suggests that ethylene affects the cold tolerance of Bermuda grass by impacting the antioxidant system, photosystem II, as well as the CBF transcriptional regulatory cascade.

Characterization and expression profiles of MaACS and MaACO genes from mulberry (Morus alba L.)*

PubMed Central

Liu, Chang-ying; Lü, Rui-hua; Li, Jun; Zhao, Ai-chun; Wang, Xi-ling; Diane, Umuhoza; Wang, Xiao-hong; Wang, Chuan-hong; Yu, Ya-sheng; Han, Shu-mei; Lu, Cheng; Yu, Mao-de

2014-01-01

1-Aminocyclopropane-1-carboxylic acid synthase (ACS) and 1-aminocyclopropane-1-carboxylic acid oxidase (ACO) are encoded by multigene families and are involved in fruit ripening by catalyzing the production of ethylene throughout the development of fruit. However, there are no reports on ACS or ACO genes in mulberry, partly because of the limited molecular research background. In this study, we have obtained five ACS gene sequences and two ACO gene sequences from Morus Genome Database. Sequence alignment and phylogenetic analysis of MaACO1 and MaACO2 showed that their amino acids are conserved compared with ACO proteins from other species. MaACS1 and MaACS2 are type I, MaACS3 and MaACS4 are type II, and MaACS5 is type III, with different C-terminal sequences. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) expression analysis showed that the transcripts of MaACS genes were strongly expressed in fruit, and more weakly in other tissues. The expression of MaACO1 and MaACO2 showed different patterns in various mulberry tissues. MaACS and MaACO genes demonstrated two patterns throughout the development of mulberry fruit, and both of them were strongly up-regulated by abscisic acid (ABA) and ethephon. PMID:25001221

Ethylene and auxin interaction in the control of adventitious rooting in Arabidopsis thaliana.

PubMed

Veloccia, A; Fattorini, L; Della Rovere, F; Sofo, A; D'Angeli, S; Betti, C; Falasca, G; Altamura, M M

2016-12-01

Adventitious roots (ARs) are post-embryonic roots essential for plant survival and propagation. Indole-3-acetic acid (IAA) is the auxin that controls AR formation; however, its precursor indole-3-butyric acid (IBA) is known to enhance it. Ethylene affects many auxin-dependent processes by affecting IAA synthesis, transport and/or signaling, but its role in AR formation has not been elucidated. This research investigated the role of ethylene in AR formation in dark-grown Arabidopsis thaliana seedlings, and its interaction with IAA/IBA. A number of mutants/transgenic lines were exposed to various treatments, and mRNA in situ hybridizations were carried out and hormones were quantified In the wild-type, the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) at 0.1 μM enhanced AR formation when combined with IBA (10 μM), but reduced it when applied alone; this effect did not occur in the ein3eil1 ethylene-insensitive mutant. ACC inhibited the expression of the IAA-biosynthetic genes WEI2, WEI7, and YUC6, but enhanced IBA-to-IAA conversion, as shown by the response of the ech2ibr10 mutant and an increase in the endogenous levels of IAA. The ethylene effect was independent of auxin-signaling by TIR1-AFB2 and IBA-efflux by ABCG carriers, but it was dependent on IAA-influx by AUX1/LAX3.Taken together, the results demonstrate that a crosstalk involving ethylene signaling, IAA-influx, and IBA-to-IAA conversion exists between ethylene and IAA in the control of AR formation. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Rhizobacterium-mediated growth promotion and expression of stress enzymes in Glycine max L. Merrill against Fusarium wilt upon challenge inoculation.

PubMed

Jain, Shekhar; Vaishnav, Anukool; Kasotia, Amrita; Kumari, Sarita; Gaur, Rajarshi Kumar; Choudhary, Devendra Kumar

2014-02-01

Wilt disease of soybean caused by a very common soil-borne fungus, Fusarium oxysporum is one of the most destructive diseases of the crop. The aim of the present study was to characterize plant growth-promotion activities and induced resistance of a rhizobacterial strain for the soybean plant against F. oxysporum. Rhizobacterium strain SJ-5 exhibited plant growth-promotion characteristics and antagonistic activity against the test pathogen on dual plate assay. It was identified as a Carnobacterium sp. A 950 bp PCR product was amplified from Carnobacterium sp. strain SJ-5, using zwittermicin A self-resistance gene-specific primers (zmaR). The strain produced indole 3-acetic acid (19 μg/ml) in the presence of salt stress and exhibited growth in Dworkin and Foster salt medium amended with 1-aminocyclopropane-1-carboxylate (ACC) through ACC deaminase activity (277 nmol/mg/h) as compared to the control. Strain seeds treated with the strain significantly enhanced the quorum of healthy plants after challenge inoculation at 14 days after seeding. An increase in the activity of stress enzymes after challenge inoculation with the test pathogen is reported. Treatment with the bacterium resulted in an increase in the chlorophyll content in the leaves in comparison with challenge-inoculated plants.

Silicon-mediated changes in polyamines participate in silicon-induced salt tolerance in Sorghum bicolor L.

PubMed

Yin, Lina; Wang, Shiwen; Tanaka, Kiyoshi; Fujihara, Shinsuke; Itai, Akihiro; Den, Xiping; Zhang, Suiqi

2016-02-01

Silicon (Si) is generally considered a beneficial element for the growth of higher plants, especially under stress conditions, but the mechanisms remain unclear. Here, we tested the hypothesis that Si improves salt tolerance through mediating important metabolism processes rather than acting as a mere mechanical barrier. Seedlings of sorghum (Sorghum bicolor L.) growing in hydroponic culture were treated with NaCl (100 mm) combined with or without Si (0.83 mm). The result showed that supplemental Si enhanced sorghum salt tolerance by decreasing Na(+) accumulation. Simultaneously, polyamine (PA) levels were increased and ethylene precursor (1-aminocyclopropane-1-carboxylic acid: ACC) concentrations were decreased. Several key PA synthesis genes were up-regulated by Si under salt stress. To further confirm the role of PA in Si-mediated salt tolerance, seedlings were exposed to spermidine (Spd) or a PA synthesis inhibitor (dicyclohexylammonium sulphate, DCHA) combined with salt and Si. Exogenous Spd showed similar effects as Si under salt stress whereas exogenous DCHA eliminated Si-enhanced salt tolerance and the beneficial effect of Si in decreasing Na(+) accumulation. These results indicate that PAs and ACC are involved in Si-induced salt tolerance in sorghum and provide evidence that Si plays an active role in mediating salt tolerance. © 2015 John Wiley & Sons Ltd.

Effects of dynamic controlled atmosphere by respiratory quotient on some quality parameters and volatile profile of 'Royal Gala' apple after long-term storage.

PubMed

Both, Vanderlei; Thewes, Fabio Rodrigo; Brackmann, Auri; de Oliveira Anese, Rogerio; de Freitas Ferreira, Daniele; Wagner, Roger

2017-01-15

The effects of dynamic controlled atmosphere (DCA) storage based on chlorophyll fluorescence (DCA-CF) and respiratory quotient (DCA-RQ) on the quality and volatile profile of 'Royal Gala' apple were evaluated. DCA storage reduces ACC (1-aminocyclopropane-1-carboxylate) oxidase activity, ethylene production and respiration rate of apples stored for 9months at 1.0°C plus 7days at 20°C, resulting in higher flesh firmness, titratable acidity and lesser physiological disorders, and provided a higher proportion of healthy fruit. Storage in a regular controlled atmosphere gave higher levels of key volatiles (butyl acetate, 2-methylbutyl acetate and hexyl acetate), as compared to fruit stored under DCA-CF, but fruit stored under DCA-RQ 1.5 and RQ 2.0 also showed higher amounts of key volatile compounds, with increment in ethanol and ethyl acetate, but far below the odour threshold. Storage in DCA-CF reduces fruit ester production, especially 2-methylbutyl acetate, which is the most important component of 'Royal Gala' apple flavour. Copyright © 2016 Elsevier Ltd. All rights reserved.

Pollination-Induced Corolla Wilting in Petunia hybrida Rapid Transfer through the Style of a Wilting-Inducing Substance.

PubMed

Gilissen, L J; Hoekstra, F A

1984-06-01

Pollination or wounding of the stigma of Petunia hybrida flowers led to the generation of a wilting factor and its transfer to the corolla within 4 hours. This was concluded from the effects of time course removal of whole styles. In this 4-hour period, pollen tubes traversed only a fraction of the total distance to the ovaries. Both pollination and wounding of the stigma immediately resulted in an increase of ethylene evolution. Accelerated wilting, however, occured only when treated styles remained connected with the ovaries, and not when they were detached and left in the flower. A wilting factor was found in eluates collected from the ovarian end of the styles, only in the case of previous pollination or wounding. In such eluates, the level of the ethylene precursor 1-amino-cyclopropane-1-carboxylic acid was below detection.These observations suggest a material nature of the wilting factor in Petunia flowers, which rapidly passes through the style to the corolla, but which is different from 1-aminocyclopropane-1-carboxylic acid.

Metabolic profiling reveals ethylene mediated metabolic changes and a coordinated adaptive mechanism of 'Jonagold' apple to low oxygen stress.

PubMed

Bekele, Elias A; Beshir, Wasiye F; Hertog, Maarten L A T M; Nicolai, Bart M; Geeraerd, Annemie H

2015-11-01

Apples are predominantly stored in controlled atmosphere (CA) storage to delay ripening and prolong their storage life. Profiling the dynamics of metabolic changes during ripening and CA storage is vital for understanding the governing molecular mechanism. In this study, the dynamics of the primary metabolism of 'Jonagold' apples during ripening in regular air (RA) storage and initiation of CA storage was profiled. 1-Methylcyclopropene (1-MCP) was exploited to block ethylene receptors and to get insight into ethylene mediated metabolic changes during ripening of the fruit and in response to hypoxic stress. Metabolic changes were quantified in glycolysis, the tricarboxylic acid (TCA) cycle, the Yang cycle and synthesis of the main amino acids branching from these metabolic pathways. Partial least square discriminant analysis of the metabolic profiles of 1-MCP treated and control apples revealed a metabolic divergence in ethylene, organic acid, sugar and amino acid metabolism. During RA storage at 18°C, most amino acids were higher in 1-MCP treated apples, whereas 1-aminocyclopropane-1-carboxylic acid (ACC) was higher in the control apples. The initial response of the fruit to CA initiation was accompanied by an increase of alanine, succinate and glutamate, but a decline in aspartate. Furthermore, alanine and succinate accumulated to higher levels in control apples than 1-MCP treated apples. The observed metabolic changes in these interlinked metabolites may indicate a coordinated adaptive strategy to maximize energy production. © 2015 Scandinavian Plant Physiology Society.

Global Transcriptomic Analysis of Targeted Silencing of Two Paralogous ACC Oxidase Genes in Banana

PubMed Central

Xia, Yan; Kuan, Chi; Chiu, Chien-Hsiang; Chen, Xiao-Jing; Do, Yi-Yin; Huang, Pung-Ling

2016-01-01

Among 18 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase homologous genes existing in the banana genome there are two genes, Mh-ACO1 and Mh-ACO2, that participate in banana fruit ripening. To better understand the physiological functions of Mh-ACO1 and Mh-ACO2, two hairpin-type siRNA expression vectors targeting both the Mh-ACO1 and Mh-ACO2 were constructed and incorporated into the banana genome by Agrobacterium-mediated transformation. The generation of Mh-ACO1 and Mh-ACO2 RNAi transgenic banana plants was confirmed by Southern blot analysis. To gain insights into the functional diversity and complexity between Mh-ACO1 and Mh-ACO2, transcriptome sequencing of banana fruits using the Illumina next-generation sequencer was performed. A total of 32,093,976 reads, assembled into 88,031 unigenes for 123,617 transcripts were obtained. Significantly enriched Gene Oncology (GO) terms and the number of differentially expressed genes (DEGs) with GO annotation were ‘catalytic activity’ (1327, 56.4%), ‘heme binding’ (65, 2.76%), ‘tetrapyrrole binding’ (66, 2.81%), and ‘oxidoreductase activity’ (287, 12.21%). Real-time RT-PCR was further performed with mRNAs from both peel and pulp of banana fruits in Mh-ACO1 and Mh-ACO2 RNAi transgenic plants. The results showed that expression levels of genes related to ethylene signaling in ripening banana fruits were strongly influenced by the expression of genes associated with ethylene biosynthesis. PMID:27681726

Ethylene Biosynthesis in Detached Young Persimmon Fruit Is Initiated in Calyx and Modulated by Water Loss from the Fruit1

PubMed Central

Nakano, Ryohei; Ogura, Emi; Kubo, Yasutaka; Inaba, Akitsugu

2003-01-01

Persimmon (Diospyros kaki Thunb.) fruit are usually classified as climacteric fruit; however, unlike typical climacteric fruits, persimmon fruit exhibit a unique characteristic in that the younger the stage of fruit detached, the greater the level of ethylene produced. To investigate ethylene induction mechanisms in detached young persimmon fruit, we cloned three cDNAs encoding 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (DK-ACS1, 2, and -3) and two encoding ACC oxidase (DK-ACO1 and -2) genes involved in ethylene biosynthesis, and we analyzed their expression in various fruit tissues. Ethylene production was induced within a few days of detachment in all fruit tissues tested, accompanied by temporally and spatially coordinated expression of all the DK-ACS and DK-ACO genes. In all tissues except the calyx, treatment with 1-methylcyclopropene, an inhibitor of ethylene action, suppressed ethylene production and ethylene biosynthesis-related gene expression. In the calyx, one ACC synthase gene (DK-ACS2) exhibited increased mRNA accumulation accompanied by a large quantity of ethylene production, and treatment of the fruit with 1-methylcyclopropene did not prevent either the accumulation of DK-ACS2 transcripts or ethylene induction. Furthermore, the alleviation of water loss from the fruit significantly delayed the onset of ethylene production and the expression of DK-ACS2 in the calyx. These results indicate that ethylene biosynthesis in detached young persimmon fruit is initially induced in calyx and is modulated by water loss through transcriptional activation of DK-ACS2. The ethylene produced in the calyx subsequently diffuses to other fruit tissues and acts as a secondary signal that stimulates autocatalytic ethylene biosynthesis in these tissues, leading to a burst of ethylene production. PMID:12529535

Ethylene biosynthesis in detached young persimmon fruit is initiated in calyx and modulated by water loss from the fruit.

PubMed

Nakano, Ryohei; Ogura, Emi; Kubo, Yasutaka; Inaba, Akitsugu

2003-01-01

Persimmon (Diospyros kaki Thunb.) fruit are usually classified as climacteric fruit; however, unlike typical climacteric fruits, persimmon fruit exhibit a unique characteristic in that the younger the stage of fruit detached, the greater the level of ethylene produced. To investigate ethylene induction mechanisms in detached young persimmon fruit, we cloned three cDNAs encoding 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (DK-ACS1, 2, and -3) and two encoding ACC oxidase (DK-ACO1 and -2) genes involved in ethylene biosynthesis, and we analyzed their expression in various fruit tissues. Ethylene production was induced within a few days of detachment in all fruit tissues tested, accompanied by temporally and spatially coordinated expression of all the DK-ACS and DK-ACO genes. In all tissues except the calyx, treatment with 1-methylcyclopropene, an inhibitor of ethylene action, suppressed ethylene production and ethylene biosynthesis-related gene expression. In the calyx, one ACC synthase gene (DK-ACS2) exhibited increased mRNA accumulation accompanied by a large quantity of ethylene production, and treatment of the fruit with 1-methylcyclopropene did not prevent either the accumulation of DK-ACS2 transcripts or ethylene induction. Furthermore, the alleviation of water loss from the fruit significantly delayed the onset of ethylene production and the expression of DK-ACS2 in the calyx. These results indicate that ethylene biosynthesis in detached young persimmon fruit is initially induced in calyx and is modulated by water loss through transcriptional activation of DK-ACS2. The ethylene produced in the calyx subsequently diffuses to other fruit tissues and acts as a secondary signal that stimulates autocatalytic ethylene biosynthesis in these tissues, leading to a burst of ethylene production.

Coupling of Physiological and Proteomic Analysis to Understand the Ethylene- and Chilling-Induced Kiwifruit Ripening Syndrome

PubMed Central

Minas, Ioannis S.; Tanou, Georgia; Karagiannis, Evangelos; Belghazi, Maya; Molassiotis, Athanassios

2016-01-01

Kiwifruit [Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson, cv. “Hayward”] is classified as climacteric fruit and the initiation of endogenous ethylene production following harvest is induced by exogenous ethylene or chilling exposure. To understand the biological basis of this “dilemma,” kiwifruit ripening responses were characterized at 20°C following treatments with exogenous ethylene (100 μL L−1, 20°C, 24 h) or/and chilling temperature (0°C, 10 days). All treatments elicited kiwifruit ripening and induced softening and endogenous ethylene biosynthesis, as determined by 1-aminocyclopropane-1-carboxylic acid (ACC) content and ACC synthase (ACS) and ACC oxidase (ACO) enzyme activities after 10 days of ripening at 20°C. Comparative proteomic analysis using two-dimensional gel electrophoresis (2DE-PAGE) and nanoscale liquid chromatography coupled to tandem mass spectrometry (nanoLC-MS/MS) revealed 81 kiwifruit proteins associated with ripening. Thirty-one kiwifruit proteins were identified as commonly regulated by the three treatments accompanied by dynamic changes of 10 proteins specific to exogenous ethylene, 2 to chilling treatment, and 12 to their combination. Ethylene and/or chilling-responsive proteins were mainly involved in disease/defense, energy, protein destination/storage, and cell structure/cell wall. Interactions between the identified proteins were demonstrated by bioinformatics analysis, allowing a more complete insight into biological pathways and molecular functions affected by ripening. The present approach provides a quantitative basis for understanding the ethylene- and chilling-induced kiwifruit ripening and climacteric fruit ripening in general. PMID:26913040

Phylloplane bacteria of Jatropha curcas: diversity, metabolic characteristics, and growth-promoting attributes towards vigor of maize seedling.

PubMed

Dubey, Garima; Kollah, Bharati; Ahirwar, Usha; Mandal, Asit; Thakur, Jyoti Kumar; Patra, Ashok Kumar; Mohanty, Santosh Ranjan

2017-10-01

The complex role of phylloplane microorganisms is less understood than that of rhizospheric microorganisms in lieu of their pivotal role in plant's sustainability. This experiment aims to study the diversity of the culturable phylloplane bacteria of Jatropha curcas and evaluate their growth-promoting activities towards maize seedling vigor. Heterotrophic bacteria were isolated from the phylloplane of J. curcas and their 16S rRNA genes were sequenced. Sequences of the 16S rRNA gene were very similar to those of species belonging to the classes Bacillales (50%), Gammaproteobacteria (21.8%), Betaproteobacteria (15.6%), and Alphaproteobacteria (12.5%). The phylloplane bacteria preferred to utilize alcohol rather than monosaccharides and polysaccharides as a carbon source. Isolates exhibited ACC (1-aminocyclopropane-1-carboxylic acid) deaminase, phosphatase, potassium solubilization, and indole acetic acid (IAA) production activities. The phosphate-solubilizing capacity (mg of PO 4 solubilized by 10 8 cells) varied from 0.04 to 0.21. The IAA production potential (μg IAA produced by 10 8 cells in 48 h) of the isolates varied from 0.41 to 9.29. Inoculation of the isolates to maize seed significantly increased shoot and root lengths of maize seedlings. A linear regression model of the plant-growth-promoting activities significantly correlated (p < 0.01) with the growth parameters. Similarly, a correspondence analysis categorized ACC deaminase and IAA production as the major factors contributing 41% and 13.8% variation, respectively, to the growth of maize seedlings.

QTL mapping of flowering time, fruit size and number in populations involving andromonoecious true lemon cucumber

USDA-ARS?s Scientific Manuscript database

Andromonoecious sex expression in cucumber is controlled by the m locus, which encodes the 1-aminocyclopropane-1 –carboxylic acid synthase (ACS) in the ethylene biosynthesis pathway. This gene seems to have pleotropic effects on fruit size and number, but the genetic basis is unknown. The True Lemon...

Hormonal changes in relation to biomass partitioning and shoot growth impairment in salinized tomato (Solanum lycopersicum L.) plants.

PubMed

Albacete, Alfonso; Ghanem, Michel Edmond; Martínez-Andújar, Cristina; Acosta, Manuel; Sánchez-Bravo, José; Martínez, Vicente; Lutts, Stanley; Dodd, Ian C; Pérez-Alfocea, Francisco

2008-01-01

Following exposure to salinity, the root/shoot ratio is increased (an important adaptive response) due to the rapid inhibition of shoot growth (which limits plant productivity) while root growth is maintained. Both processes may be regulated by changes in plant hormone concentrations. Tomato plants (Solanum lycopersicum L. cv Moneymaker) were cultivated hydroponically for 3 weeks under high salinity (100 mM NaCl) and five major plant hormones (abscisic acid, ABA; the cytokinins zeatin, Z, and zeatin-riboside, ZR; the auxin indole-3-acetic acid, IAA; and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid, ACC) were determined weekly in roots, xylem sap, and leaves. Salinity reduced shoot biomass by 50-60% and photosynthetic area by 20-25% both by decreasing leaf expansion and delaying leaf appearance, while root growth was less affected, thus increasing the root/shoot ratio. ABA and ACC concentrations strongly increased in roots, xylem sap, and leaves after 1 d (ABA) and 15 d (ACC) of salinization. By contrast, cytokinins and IAA were differentially affected in roots and shoots. Salinity dramatically decreased the Z+ZR content of the plant, and induced the conversion of ZR into Z, especially in the roots, which accounted for the relative increase of cytokinins in the roots compared to the leaf. IAA concentration was also strongly decreased in the leaves while it accumulated in the roots. Decreased cytokinin content and its transport from the root to the shoot were probably induced by the basipetal transport of auxin from the shoot to the root. The auxin/cytokinin ratio in the leaves and roots may explain both the salinity-induced decrease in shoot vigour (leaf growth and leaf number) and the shift in biomass allocation to the roots, in agreement with changes in the activity of the sink-related enzyme cell wall invertase.

Ethylene emission and PR protein synthesis in ACC deaminase producing Methylobacterium spp. inoculated tomato plants (Lycopersicon esculentum Mill.) challenged with Ralstonia solanacearum under greenhouse conditions.

PubMed

Yim, Woojong; Seshadri, Sundaram; Kim, Kiyoon; Lee, Gillseung; Sa, Tongmin

2013-06-01

Bacteria of genus Methylobacterium have been found to promote plant growth and regulate the level of ethylene in crop plants. This work is aimed to test the induction of defense responses in tomato against bacterial wilt by stress ethylene level reduction mediated by the ACC deaminase activity of Methylobacterium strains. Under greenhouse conditions, the disease index value in Methylobacterium sp. inoculated tomato plants was lower than control plants. Plants treated with Methylobacterium sp. challenge inoculated with Ralstonia solanacearum (RS) showed significantly reduced disease symptoms and lowered ethylene emission under greenhouse condition. The ACC and ACO (1-aminocyclopropane-1-carboxylate oxidase) accumulation in tomato leaves were significantly reduced with Methylobacterium strains inoculation. While ACC oxidase gene expression was found higher in plants treated with R. solanacearum than Methylobacterium sp. treatment, PR proteins related to induced systemic resistance like β-1,3-glucanase, PAL, PO and PPO were increased in Methylobacterium sp. inoculated plants. A significant increase in β-1,3-glucanase and PAL gene expression was found in all the Methylobacterium spp. treatments compared to the R. solanacearum treatment. This study confirms the activity of Methylobacterium sp. in increasing the defense enzymes by modulating the ethylene biosynthesis pathway and suggests the use of methylotrophic bacteria as potential biocontrol agents in tomato cultivation. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Determination of ACC-induced cell-programmed death in roots of Vicia faba ssp. minor seedlings by acridine orange and ethidium bromide staining.

PubMed

Byczkowska, Anna; Kunikowska, Anita; Kaźmierczak, Andrzej

2013-02-01

Fluorescence staining with acridine orange (AO) and ethidium bromide (EB) showed that nuclei of cortex root cells of 1-aminocyclopropane-1-carboxylic acid (ACC)-treated Vicia faba ssp. minor seedlings differed in color. Measurement of resultant fluorescence intensity (RFI) showed that it increased when the color of nuclear chromatin was changed from green to red, indicating that EB moved to the nuclei via the cell membrane which lost its integrity and stained nuclei red. AO/EB staining showed that changes in color of the nuclear chromatin were accompanied by DNA condensation, nuclei fragmentation, and chromatin degradation which were also shown after 4,6-diamidino-2-phenylindol staining. These results indicate that ACC induced programmed cell death. The increasing values of RFI together with the corresponding morphological changes of nuclear chromatin were the basis to prepare the standard curve; cells with green unchanged nuclear chromatin were alive while those with dark orange and bright red nuclei were dead. The cells with nuclei with green-yellow, yellow-orange, and bright orange chromatin with or without their condensation and fragmentation chromatin were dying. The prepared curve has became the basis to draw up the digital method for detection and determination of the number of living, dying, and dead cells in an in planta system and revealed that ACC induced death in about 20% of root cortex cells. This process was accompanied by increase in ion leakage, shortening of cells and whole roots, as well as by increase in weight and width of the apical part of roots and appearance of few aerenchymatic spaces while not by internucleosomal DNA degradation.

[Cloning, expression and transcriptional analysis of biotin carboxyl carrier protein gene (accA) from Amycolatopsis mediterranei U32 ].

PubMed

Lu, Jie; Yao, Yufeng; Jiang, Weihong; Jiao, Ruishen

2003-02-01

Acetyl CoA carboxylase (EC 6.4.1.2, ACC) catalyzes the ATP-dependent carboxylation of acetyl CoA to yield malonyl CoA, which is the first committed step in fatty acid synthesis. A pair of degenerate PCR primers were designed according to the conserved amino acid sequence of AccA from M. tuberculosis and S. coelicolor. The product of the PCR amplification, a DNA fragment of 250bp was used as a probe for screening the U32 genomic cosmid library and its gene, accA, coding the biotinylated protein subunit of acetyl CoA carboxylase, was successfully cloned from U32. The accA ORF encodes a 598-amino-acid protein with the calculated molecular mass of 63.7kD, with 70.1% of G + C content. A typical Streptomyces RBS sequence, AGGAGG, was found at the - 6 position upstream of the start codon GTG. Analysis of the deduced amino acid sequence showed the presence of biotin-binding site and putative ATP-bicarbonate interaction region, which suggested the U32 AccA may act as a biotin carboxylase as well as a biotin carrier protein. Gene accA was then cloned into the pET28 (b) vector and expressed solubly in E. coli BL21 (DE3) by 0.1 mmol/L IPTG induction. Western blot confirmed the covalent binding of biotin with AccA. Northern blot analyzed transcriptional regulation of accA by 5 different nitrogen sources.

Transcriptional regulation of genes encoding ABA metabolism enzymes during the fruit development and dehydration stress of pear 'Gold Nijisseiki'.

PubMed

Dai, Shengjie; Li, Ping; Chen, Pei; Li, Qian; Pei, Yuelin; He, Suihuan; Sun, Yufei; Wang, Ya; Kai, Wenbin; Zhao, Bo; Liao, Yalan; Leng, Ping

2014-09-01

To investigate the contribution of abscisic acid (ABA) in pear 'Gold Nijisseiki' during fruit ripening and under dehydration stress, two cDNAs (PpNCED1 and PpNCED2) which encode 9-cis-epoxycarotenoid dioxygenase (NCED) (a key enzyme in ABA biosynthesis), two cDNAs (PpCYP707A1 and PpCYP707A2) which encode 8'-hydroxylase (a key enzyme in the oxidative catabolism of ABA), one cDNA (PpACS3) which encodes 1-aminocyclopropane-1-carboxylic acid (ACC), and one cDNA (PpACO1) which encodes ACC oxidase involved in ethylene biosynthesis were cloned from 'Gold Nijisseiki' fruit. In the pulp, peel and seed, expressions of PpNCED1 and PpNCED2 rose in two stages which corresponded with the increase of ABA levels. The expression of PpCYP707A1 dramatically declined after 60-90 days after full bloom (DAFB) in contrast to the changes of ABA levels during this period, while PpCYP707A2 stayed low during the whole development of fruit. Application of exogenous ABA at 100 DAFB increased the soluble sugar content and the ethylene release but significantly decreased the titratable acid and chlorophyll contents in fruits. When fruits harvested at 100 DAFB were stored in the laboratory (25 °C, 50% relative humidity), the ABA content and the expressions of PpNCED1/2 and PpCYP707A1 in the pulp, peel and seed increased significantly, while ethylene reached its highest value after the maximum peak of ABA accompanied with the expressions of PpACS3 and PpACO1. In sum the endogenous ABA may play an important role in the fruit ripening and dehydration of pear 'Gold Nijisseiki' and the ABA level was regulated mainly by the dynamics of PpNCED1, PpNCED2 and PpCYP707A1 at the transcriptional level. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Endogenous ethylene does not regulate opening of unstressed Iris flowers but strongly inhibits it in water-stressed flowers.

PubMed

Çelikel, Fisun G; van Doorn, Wouter G

2012-09-15

The floral buds of Iris flowers (Iris x hollandica) are enclosed by two sheath leaves. Flower opening depends on lifting the flower up to a position whereby the tepals can move laterally. This upward movement is carried out by elongation of the subtending pedicel and ovary. In the pedicels and ovaries of unstressed control flowers, the concentration of ACC (1-aminocyclopropane-1-carboxylic acid) and the rate of ethylene production increased during d 0-1 of flower opening, and then decreased. Exposure to ≥200 nL L(-1) ethylene for 24 h at 20°C inhibited elongation of the pedicel+ovary, and inhibited flower opening. However, pulsing of unstressed flowers with solutions containing inhibitors of ethylene synthesis (AOA, AVG), or an inhibitor of ethylene action (STS), did not affect pedicel+ovary elongation or flower opening. When the flowers were dehydrated for 2 d at 20°C and 60% RH, they did not open when subsequently placed in water, and showed inhibited elongation in the pedicel+ovary. This dehydration treatment resulted in elevated pedicel+ovary ACC levels and in increased ethylene production. Treatment with STS prevented the increase in ACC levels and ethylene production, overcame the effect of dehydration on elongation of the pedicel+ovary, and resulted in full flower opening. It is concluded that flower opening in unstressed Iris flowers is not regulated by endogenous ethylene. An increase in endogenous ethylene above normal levels during stress, by contrast, strongly inhibited flower opening, due to its inhibitory effect on elongation of the pedicel+ovary. Copyright © 2012 Elsevier GmbH. All rights reserved.

Bioremediation of heavy metals using an endophytic bacterium Paenibacillus sp. RM isolated from the roots of Tridax procumbens.

PubMed

Govarthanan, M; Mythili, R; Selvankumar, T; Kamala-Kannan, S; Rajasekar, A; Chang, Young-Cheol

2016-12-01

The aim of the present study was to assess the bioremediation potential of endophytic bacteria isolated from roots of Tridax procumbens plant. Five bacterial endophytes were isolated and subsequently tested for minimal inhibitory concentration (MIC) against different heavy metals. Amongst the five isolates, strain RM exhibited the highest resistance to copper (750 mg/l), followed by zinc (500 mg/l), lead (450 mg/l), and arsenic (400 mg/l). Phylogenetic analysis of the 16S rDNA sequence suggested that strain RM was a member of genus Paneibacillus. Strain RM also had the capacity to produce secondary metabolites, indole acetic acid, siderophores, 1-aminocyclopropane-1-carboxylate (ACC) deaminase, and biosurfactant and solubilize phosphate. The growth kinetics of strain RM was altered slightly in the presence of metal stress. Temperature and pH influenced the metal removal rate. The results suggest that strain RM can survive under the high concentration of heavy metals and has been identified as a potential candidate for application in bioremediation of heavy metals in contaminated environments.

Genetic and functional characterization of culturable plant-beneficial actinobacteria associated with yam rhizosphere.

PubMed

Arunachalam Palaniyandi, Sasikumar; Yang, Seung Hwan; Damodharan, Karthiyaini; Suh, Joo-Won

2013-12-01

Actinobacteria were isolated from the rhizosphere of yam plants from agricultural fields from Yeoju, South Korea and analyzed for their genetic and plant-beneficial functional diversity. A total of 29 highly occurring actinobacterial isolates from the yam rhizosphere were screened for various plant-beneficial traits such as antimicrobial activity on fungi and bacteria; biocontrol traits such as production of siderophore, protease, chitinase, endo-cellulase, and β-glucanase. The isolates were also screened for plant growth-promoting (PGP) traits such as auxin production, phosphate solubilization, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, and in vitro Arabidopsis growth promotion. 16S rDNA sequence-based phylogenetic analysis was carried out on the actinobacterial isolates to determine their genetic relatedness to known actinobacteria. BOX-PCR analysis revealed high genetic diversity among the isolates. Several isolates were identified to belong to the genus Streptomyces and a few to Kitasatospora. The actinobacterial strains exhibited high diversity in their functionality and were identified as novel and promising candidates for future development into biocontrol and PGP agents. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A novel allele of monoecious (m) locus is responsible for elongated fruit shape and perfect flowers in cucumber (Cucumis sativus L.)

USDA-ARS?s Scientific Manuscript database

In cucumber (Cucumis sativus L.), sex determination is controlled primarily by the F (female) and M (monoecy) loci. Homozygous recessive mm plants bear bisexual (perfect) flowers and the fruits are often round shaped. CsACS2 encoding the 1-aminocyclopropane-1-carboxylic acid synthase has been shown ...

Role of ethylene and related gene expression in the interaction between strawberry plants and the plant growth-promoting bacterium Azospirillum brasilense.

PubMed

Elías, J M; Guerrero-Molina, M F; Martínez-Zamora, M G; Díaz-Ricci, J C; Pedraza, R O

2018-05-01

Induced systemic resistance (ISR) is one of the indirect mechanisms of growth promotion exerted by plant growth-promoting bacteria, and can be mediated by ethylene (ET). We assessed ET production and the expression of related genes in the Azospirillum-strawberry plant interaction. Ethylene production was evaluated by gas chromatography in plants inoculated or not with A. brasilense REC3. Also, plants were treated with AgNO 3 , an inhibitor of ET biosynthesis; with 1-aminocyclopropane-1-carboxylic acid (ACC), a precursor of ET biosynthesis; and with indole acetic acid (IAA). Plant dry biomass and the growth index were determined to assess the growth-promoting effect of A. brasilense REC3 in strawberry plants. Quantitative real time PCR (qRT-PCR) was performed to analyse relative expression of the genes Faetr1, Faers1 and Faein4, which encode ET receptors; Factr1 and Faein2, involved in the ET signalling pathway; Faacs1 encoding ACC synthase; Faaco1 encoding ACC oxidase; and Faaux1 and Faami1 for IAA synthesis enzymes. Results showed that ET acts as a rapid and transient signal in the first 12 h post-treatment. A. brasilense REC3-inoculated plants had a significantly higher growth index compared to control plants. Modulation of the genes Faetr1, Faers1, Faein4, Factr1, Faein2 and Faaco1 indicated activation of ET synthesis and signalling pathways. The up-regulation of Faaux1 and Faami1 involved in IAA synthesis suggested that inoculation with A. brasilense REC3 induces production of this auxin, modulating ET signalling. Ethylene production and up-regulation of genes associated with ET signalling in strawberry plants inoculated with A. brasilense REC3 support the priming activation characteristic of ISR. This type of resistance and the activation of systemic acquired resistance previously observed in this interaction indicate that both are present in strawberry plants, could act synergistically and increase protection against pathogens. © 2018 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

Antiphase light and temperature cycles affect PHYTOCHROME B-controlled ethylene sensitivity and biosynthesis, limiting leaf movement and growth of Arabidopsis.

PubMed

Bours, Ralph; van Zanten, Martijn; Pierik, Ronald; Bouwmeester, Harro; van der Krol, Alexander

2013-10-01

In the natural environment, days are generally warmer than the night, resulting in a positive day/night temperature difference (+DIF). Plants have adapted to these conditions, and when exposed to antiphase light and temperature cycles (cold photoperiod/warm night [-DIF]), most species exhibit reduced elongation growth. To study the physiological mechanism of how light and temperature cycles affect plant growth, we used infrared imaging to dissect growth dynamics under +DIF and -DIF in the model plant Arabidopsis (Arabidopsis thaliana). We found that -DIF altered leaf growth patterns, decreasing the amplitude and delaying the phase of leaf movement. Ethylene application restored leaf growth in -DIF conditions, and constitutive ethylene signaling mutants maintain robust leaf movement amplitudes under -DIF, indicating that ethylene signaling becomes limiting under these conditions. In response to -DIF, the phase of ethylene emission advanced 2 h, but total ethylene emission was not reduced. However, expression analysis on members of the 1-aminocyclopropane-1-carboxylic acid (ACC) synthase ethylene biosynthesis gene family showed that ACS2 activity is specifically suppressed in the petiole region under -DIF conditions. Indeed, petioles of plants under -DIF had reduced ACC content, and application of ACC to the petiole restored leaf growth patterns. Moreover, acs2 mutants displayed reduced leaf movement under +DIF, similar to wild-type plants under -DIF. In addition, we demonstrate that the photoreceptor PHYTOCHROME B restricts ethylene biosynthesis and constrains the -DIF-induced phase shift in rhythmic growth. Our findings provide a mechanistic insight into how fluctuating temperature cycles regulate plant growth.

Stimulation of the growth of Jatropha curcas by the plant growth promoting bacterium Enterobacter cancerogenus MSA2.

PubMed

Jha, Chaitanya Kumar; Patel, Baldev; Saraf, Meenu

2012-03-01

A novel Enterobacter cancerogenus MSA2 is a plant growth promoting gamma-proteobacterium that was isolated from the rhizosphere of Jatropha cucas a potentially important biofuel feed stock plant. Based on phenotypic, physiological, biochemical and phylogenetic studies, strain MSA2 could be classified as a member of E. cancerogenus. However, comparisons of characteristics with other known species of the genus Enterobacter suggested that strain MSA2 could be a novel PGPB strain. In vitro studies were carried for the plant growth promoting attribute of this culture. It tested positive for ACC (1-aminocyclopropane-1-carboxylic acid) deaminase production, phytase, phosphate solubilization, IAA (Indole acetic acid) production, siderophore, and ammonia production. The isolate was then used as a inoculant for the vegetative study of Jatropha curcas plant. Enterobacter cancerogenus MSA2 supplemented with 1% carboxymethylcellulose showed overall plant growth promotion effect resulting in enhanced root length (124.14%), fresh root mass (81%), fresh shoot mass (120.02%), dry root mass (124%), dry shoot mass (105.54%), number of leaf (30.72%), chlorophyll content (50.41%), and biomass (87.20%) over control under the days of experimental observation. This study was designed for 120 days and was in triplicate and the data was collected at every 30 days.

Molecular cloning and expression of heteromeric ACCase subunit genes from Jatropha curcas.

PubMed

Gu, Keyu; Chiam, Huihui; Tian, Dongsheng; Yin, Zhongchao

2011-04-01

Acetyl-CoA carboxylase (ACCase) catalyzes the biotin-dependent carboxylation of acetyl-CoA to produce malonyl-CoA, which is the essential first step in the biosynthesis of long-chain fatty acids. ACCase exists as a multi-subunit enzyme in most prokaryotes and the chloroplasts of most plants and algae, while it is present as a multi-domain enzyme in the endoplasmic reticulum of most eukaryotes. The heteromeric ACCase of higher plants consists of four subunits: an α-subunit of carboxyltransferase (α-CT, encoded by accA gene), a biotin carboxyl carrier protein (BCCP, encoded by accB gene), a biotin carboxylase (BC, encoded by accC gene) and a β-subunit of carboxyltransferase (β-CT, encoded by accD gene). In this study, we cloned and characterized the genes accA, accB1, accC and accD that encode the subunits of heteromeric ACCase in Jatropha (Jatropha curcas), a potential biofuel plant. The full-length cDNAs of the four subunit genes were isolated from a Jatropha cDNA library and by using 5' RACE, whereas the genomic clones were obtained from a Jatropha BAC library. They encode a 771 amino acid (aa) α-CT, a 286-aa BCCP1, a 537-aa BC and a 494-aa β-CT, respectively. The single-copy accA, accB1 and accC genes are nuclear genes, while the accD gene is located in chloroplast genome. Jatropha α-CT, BCCP1, BC and β-CT show high identity to their homologues in other higher plants at amino acid level and contain all conserved domains for ACCase activity. The accA, accB1, accC and accD genes are temporally and spatially expressed in the leaves and endosperm of Jatropha plants, which are regulated by plant development and environmental factors. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

[Biodiversity of phosphate-dissolving and plant growth--promoting endophytic bacteria of two crops].

PubMed

Huang, Jing; Sheng, Xiafang; He, Linyan

2010-06-01

We isolated and characterized phosphate-dissolving endophytic bacteria from two commonly cultivated crops. Phosphate-dissolving endophytic bacteria were isolated by plating and screening from interior tissues of rape and maize plants on NBRIP medium with tricalcium phosphate as sole phosphate source. Bacteria were characterized regarding characteristics that may be relevant for a beneficial plant-microbe interaction-indoleacetic acid, siderophore and 1-aminocyclopropane-1-carboxylic acid deaminase production,and further classified by restriction analysis of 16S rDNA. Eleven typical strains were identified by 16S rDNA sequence analysis. Thirty-two phosphate-dissolving endophytic bacteria were isolated from maize and rape plants and classified by restriction analysis of 16S rDNA in 8 different taxonomic groups at the similarity level of 76%. All the isolates could release phosphate from tricalcium phosphate and decrease the pH of the medium. The maximum phosphate content (537.6 mg/L) in the solution was obtained with strain M1L5. Thirteen isolates isolated from rape produced indoleacetic acid and siderophore, 68.4% and 63.2% of the strains isolated from maize produced indoleacetic acid and siderophore,respectively. 63.2% of the strains isolated from maize were able to grow on 1-aminocyclopropane-1-carboxylic acid as the sole nitrogen source. The eleven strains belonged to five different genera including Pantoea, Pseudomonas, Burkholderia, Acinetobacter and Ralstonia. Phosphate-dissolving endophytic bacteria isolated from rape and maize plants have abundant characteristics relative to promoting plant growth and genetic diversity.

Malus hupehensis NPR1 induces pathogenesis-related protein gene expression in transgenic tobacco.

PubMed

Zhang, J-Y; Qiao, Y-S; Lv, D; Gao, Z-H; Qu, S-C; Zhang, Z

2012-03-01

Most commercially grown apple cultivars are susceptible to fungal diseases. Malus hupehensis has high resistance to many diseases affecting apple cultivars. Understanding innate defence mechanisms would help to develop disease-resistant apple crops. Non-expressor of pathogenesis-related genes 1 (NPR1) plays a key role in regulating salicylic acid (SA)-mediated systemic acquired resistance (SAR). MhNPR1 cDNA, corresponding to genomic DNA and its 5' flanking sequences, was isolated from M. hupehensis. Sequence analysis showed that the regulatory mechanism for oligomer-monomer transition of the MhNPR1 protein in apple might be similar to that of GmNPR1 in soybean, but different from that of AtNPR1 in Arabidopsis. No significant differences in MhNPR1 expression were found in M. hupehensis after infection with Botryosphaeria berengeriana, showing that MhNPR1 might be regulated by pathogens at the protein level, as described for Arabidopsis and grapevine. SA treatment significantly induced MhNPR1 expression in leaves, stems and roots, while methyl jasmonate (MeJA) treatment induced MhNPR1 expression in roots, but not in leaves or stems. The expression of MhNPR1 was highly increased in roots, moderately in leaves, and did not change in stems after treatment with 1-aminocyclopropane-1-carboxylic acid (ACC). SAR marker genes (MhPR1 and MhPR5) were induced by SA, MeJA and ACC in leaves, stems and roots. Overexpression of MhNPR1 significantly induced the expression of pathogenesis-related genes (NtPR1, NtPR3 and NtPR5) in transgenic tobacco plants and resistance to the fungus Botrytis cinerea, suggesting that MhNPR1 orthologues are a component of the SA defence signalling pathway and SAR is induced in M. hupehensis. © 2011 German Botanical Society and The Royal Botanical Society of the Netherlands.

Complementary DNA cloning of the pear 1-aminocyclopropane-1-carboxylic acid oxidase gene and agrobacterium-mediated anti-sense genetic transformation.

PubMed

Qi, Jing; Dong, Zhen; Zhang, Yu-Xing

2015-12-01

The aim of the present study was to genetically modify plantlets of the Chinese yali pear to reduce their expression of ripening-associated 1-aminocyclopropane-1-carboxylic acid oxidase (ACO) and therefore increase the shelf-life of the fruit. Primers were designed with selectivity for the conserved regions of published ACO gene sequences, and yali complementary DNA (cDNA) cloning was performed by reverse transcription quantitative polymerase chain reaction (PCR). The obtained cDNA fragment contained 831 base pairs, encoding 276 amino acid residues, and shared no less than 94% nucleotide sequence identity with other published ACO genes. The cDNA fragment was inversely inserted into a pBI121 expression vector, between the cauliflower mosaic virus 35S promoter and the nopaline synthase terminator, in order to construct the anti‑sense expression vector of the ACO gene; it was transfected into cultured yali plants using Agrobacterium LBA4404. Four independent transgenic lines of pear plantlets were obtained and validated by PCR analysis. A Southern blot assay revealed that there were three transgenic lines containing a single copy of exogenous gene and one line with double copies. The present study provided germplasm resources for the cultivation of novel storage varieties of pears, therefore providing a reference for further applications of anti‑sense RNA technology in the genetic improvement of pears and other fruit.

Better Rooting Procedure to Enhance Survival Rate of Field Grown Malaysian Eksotika Papaya Transformed with 1-Aminocyclopropane-1-Carboxylic Acid Oxidase Gene

PubMed Central

Sekeli, Rogayah; Abdullah, Janna Ong; Namasivayam, Parameswari; Muda, Pauziah; Abu Bakar, Umi Kalsom

2013-01-01

A high survival rate for transformed papaya plants when transferred to the field is useful in the quest for improving the commercial quality traits. We report in this paper an improved rooting method for the production of transformed Malaysian Eksotika papaya with high survival rate when transferred to the field. Shoots were regenerated from embryogenic calli transformed with antisense and RNAi constructs of 1-aminocyclopropane-1-carboxylic acid oxidase (ACO) genes using the Agrobacterium tumefaciens-mediated transformation method. Regenerated transformed shoots, each measuring approximately 3-4 cm in height, were cultured in liquid half-strength Murashige and Skoog (MS) medium or sterile distilled water, and with either perlite or vermiculite supplementation. All the culturing processes were conducted either under sterile or nonsterile condition. The results showed that rooting under sterile condition was better. Shoots cultured in half-strength MS medium supplemented with vermiculite exhibited a 92.5% rooting efficiency while perlite showed 77.5%. The survival rate of the vermiculite-grown transformed papaya plantlets after transfer into soil, contained in polybags, was 94%, and the rate after transfer into the ground was 92%. Morpho-histological analyses revealed that the tap roots were more compact, which might have contributed to the high survival rates of the plantlets. PMID:25969786

Better rooting procedure to enhance survival rate of field grown malaysian eksotika papaya transformed with 1-aminocyclopropane-1-carboxylic Acid oxidase gene.

PubMed

Sekeli, Rogayah; Abdullah, Janna Ong; Namasivayam, Parameswari; Muda, Pauziah; Abu Bakar, Umi Kalsom

2013-01-01

A high survival rate for transformed papaya plants when transferred to the field is useful in the quest for improving the commercial quality traits. We report in this paper an improved rooting method for the production of transformed Malaysian Eksotika papaya with high survival rate when transferred to the field. Shoots were regenerated from embryogenic calli transformed with antisense and RNAi constructs of 1-aminocyclopropane-1-carboxylic acid oxidase (ACO) genes using the Agrobacterium tumefaciens-mediated transformation method. Regenerated transformed shoots, each measuring approximately 3-4 cm in height, were cultured in liquid half-strength Murashige and Skoog (MS) medium or sterile distilled water, and with either perlite or vermiculite supplementation. All the culturing processes were conducted either under sterile or nonsterile condition. The results showed that rooting under sterile condition was better. Shoots cultured in half-strength MS medium supplemented with vermiculite exhibited a 92.5% rooting efficiency while perlite showed 77.5%. The survival rate of the vermiculite-grown transformed papaya plantlets after transfer into soil, contained in polybags, was 94%, and the rate after transfer into the ground was 92%. Morpho-histological analyses revealed that the tap roots were more compact, which might have contributed to the high survival rates of the plantlets.

The Mediator Complex Subunits MED14, MED15, and MED16 Are Involved in Defense Signaling Crosstalk in Arabidopsis.

PubMed

Wang, Chenggang; Du, Xuezhu; Mou, Zhonglin

2016-01-01

Mediator is a highly conserved protein complex that functions as a transcriptional coactivator in RNA polymerase II (RNAPII)-mediated transcription. The Arabidopsis Mediator complex has recently been implicated in plant immune responses. Here, we compared salicylic acid (SA)-, methyl jasmonate (MeJA)-, and the ethylene (ET) precursor 1-aminocyclopropane-1-carboxylic acid (ACC)-induced defense and/or wound-responsive gene expression in 14 Arabidopsis Mediator subunit mutants. Our results show that MED14, MED15, and MED16 are required for SA-activated expression of the defense marker gene PATHOEGNESIS-RELATED GENE1 , MED25 is required for MeJA-induced expression of the wound-responsive marker gene VEGATATIVE STORAGE PROTEIN1 ( VSP1 ), MED8, MED14, MED15, MED16, MED18, MED20a, MED25, MED31, and MED33A/B (MED33a and MED33B) are required for MeJA-induced expression of the defense maker gene PLANT DEFENSIN1.2 ( PDF1.2 ), and MED8, MED14, MED15, MED16, MED25, and MED33A/B are also required for ACC-triggered expression of PDF1.2 . Furthermore, we investigated the involvement of MED14, MED15, and MED16 in plant defense signaling crosstalk and found that MED14, MED15, and MED16 are required for SA- and ET-mediated suppression of MeJA-induced VSP1 expression. This result suggests that MED14, MED15, and MED16 not only relay defense signaling from the SA and JA/ET defense pathways to the RNAPII transcription machinery, but also fine-tune defense signaling crosstalk. Finally, we show that MED33A/B contributes to the necrotrophic fungal pathogen Botrytis cinerea- induced expression of the defense genes PDF1.2, HEVEIN-LIKE , and BASIC CHITINASE and is required for full-scale basal resistance to B. cinerea , demonstrating a positive role for MED33 in plant immunity against necrotrophic fungal pathogens.

Real time expression of ACC oxidase and PR-protein genes mediated by Methylobacterium spp. in tomato plants challenged with Xanthomonas campestris pv. vesicatoria.

PubMed

Yim, W J; Kim, K Y; Lee, Y W; Sundaram, S P; Lee, Y; Sa, T M

2014-07-15

Biotic stress like pathogenic infection increases ethylene biosynthesis in plants and ethylene inhibitors are known to alleviate the severity of plant disease incidence. This study aimed to reduce the bacterial spot disease incidence in tomato plants caused by Xanthomonas campestris pv. vesicatoria (XCV) by modulating stress ethylene with 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity of Methylobacterium strains. Under greenhouse condition, Methylobacterium strains inoculated and pathogen challenged tomato plants had low ethylene emission compared to pathogen infected ones. ACC accumulation and ACC oxidase (ACO) activity with ACO related gene expression increased in XCV infected tomato plants over Methylobacterium strains inoculated plants. Among the Methylobacterium spp., CBMB12 resulted lowest ACO related gene expression (1.46 Normalized Fold Expression), whereas CBMB20 had high gene expression (3.42 Normalized Fold Expression) in pathogen challenged tomato. But a significant increase in ACO gene expression (7.09 Normalized Fold Expression) was observed in the bacterial pathogen infected plants. In contrast, Methylobacterium strains enhanced β-1,3-glucanase and phenylalanine ammonia-lyase (PAL) enzyme activities in pathogen challenged tomato plants. The respective increase in β-1,3-glucanase related gene expressions due to CBMB12, CBMB15, and CBMB20 strains were 66.3, 25.5 and 10.4% higher over pathogen infected plants. Similarly, PAL gene expression was high with 0.67 and 0.30 Normalized Fold Expression, in pathogen challenged tomato plants inoculated with CBMB12 and CBMB15 strains. The results suggest that ethylene is a crucial factor in bacterial spot disease incidence and that methylobacteria with ACC deaminase activity can reduce the disease severity with ultimate pathogenesis-related protein increase in tomato. Copyright © 2014 Elsevier GmbH. All rights reserved.

[Characterization of growth-promoting rhizobacteria in Eucalyptus nitens seedlings].

PubMed

Angulo, Violeta C; Sanfuentes, Eugenio A; Rodríguez, Francisco; Sossa, Katherine E

2014-01-01

Rhizospheric and endophytic bacteria were isolated from the rizosphere and root tissue of Eucalyptus nitens. The objective of this work was to evaluate their capacity to promote growth in seedlings of the same species under greenhouse conditions. The isolates that improved seedling growth were identified and characterized by their capacity to produce indoleacetic acid (IAA), solubilize phosphates and increase 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. One hundred and five morphologically different strains were isolated, 15 of which promoted E. nitens seedling growth, significantly increasing the height (50%), root length (45%) as well as the aerial and root dry weight (142% and 135% respectively) of the plants. Bacteria belonged to the genus Arthrobacter, Lysinibacillus, Rahnella and Bacillus. Isolates A. phenanthrenivorans 21 and B. cereus 113 improved 3.15 times the emergence of E. nitens after 12 days, compared to control samples. Among isolated R. aquatilis, 78 showed the highest production of IAA (97.5±2.87 μg/ml) in the presence of tryptophan and the highest solubilizer index (2.4) for phosphorus, while B. amyloliquefaciens 60 isolate was positive for ACC deaminase activity. Our results reveal the potential of the studied rhizobacteria as promoters of emergence and seedling growth of E. nitens, and their possible use as PGPR inoculants, since they have more than one mechanism associated with plant growth promotion. Copyright © 2014 Asociación Argentina de Microbiología. Publicado por Elsevier España. All rights reserved.

Contrasting effects of ethylene biosynthesis on induced plant resistance against a chewing and a piercing-sucking herbivore in rice.

PubMed

Lu, Jing; Li, Jiancai; Ju, Hongping; Liu, Xiaoli; Erb, Matthias; Wang, Xia; Lou, Yonggen

2014-11-01

Ethylene is a stress hormone with contrasting effects on herbivore resistance. However, it remains unknown whether these differences are plant- or herbivore-specific. We cloned a rice 1-aminocyclopropane-1-carboxylic acid (ACC) synthase gene, OsACS2, whose transcripts were rapidly up-regulated in response to mechanical wounding and infestation by two important pests: the striped stem borer (SSB) Chilo suppressalis and the brown planthopper (BPH) Nilaparvata lugens. Antisense expression of OsACS2 (as-acs) reduced elicited ethylene emission, SSB-elicited trypsin protease inhibitor (TrypPI) activity, SSB-induced volatile release, and SSB resistance. Exogenous application of ACC restored TrypPI activity and SSB resistance. In contrast to SSB, BPH infestation increased volatile emission in as-acs lines. Accordingly, BPH preferred to feed and oviposit on wild-type (WT) plants--an effect that could be attributed to two repellent volatiles, 2-heptanone and 2-heptanol, that were emitted in higher amounts by as-acs plants. BPH honeydew excretion was reduced and natural enemy attraction was enhanced in as-acs lines, resulting in higher overall resistance to BPH. These results demonstrate that ethylene signaling has contrasting, herbivore-specific effects on rice defense responses and resistance against a chewing and a piercing-sucking insect, and may mediate resistance trade-offs between herbivores of different feeding guilds in rice. © The Author 2014. Published by the Molecular Plant Shanghai Editorial Office in association with Oxford University Press on behalf of CSPB and IPPE, SIBS, CAS.

Detection of biosynthetic gene and phytohormone production by endophytic actinobacteria associated with Solanum lycopersicum and their plant-growth-promoting effect.

PubMed

Passari, Ajit Kumar; Chandra, Preeti; Zothanpuia; Mishra, Vineet Kumar; Leo, Vincent Vineeth; Gupta, Vijai Kumar; Kumar, Brijesh; Singh, Bhim Pratap

2016-10-01

In the present study, fifteen endophytic actinobacterial isolates recovered from Solanum lycopersicum were studied for their antagonistic potential and plant-growth-promoting (PGP) traits. Among them, eight isolates showed significant antagonistic and PGP traits, identified by amplification of the 16S rRNA gene. Isolate number DBT204, identified as Streptomyces sp., showed multiple PGP traits tested in planta and improved a range of growth parameters in seedlings of chili (Capsicum annuum L.) and tomato (S. lycopersicum L.). Further, genes of indole acetic acid (iaaM) and 1-aminocyclopropane-1-carboxylate (ACC) deaminase (acdS) were successively amplified from five strains. Six antibiotics (trimethoprim, fluconazole, chloramphenicol, nalidixic acid, rifampicin and streptomycin) and two phytohormones [indole acetic acid (IAA) and kinetin (KI)] were detected and quantified in Streptomyces sp. strain DBT204 using UPLC-ESI-MS/MS. The study indicates the potential of these PGP strains for production of phytohormones and shows the presence of biosynthetic genes responsible for production of secondary metabolites. It is the first report showing production of phytohormones (IAA and KI) by endophytic actinobacteria having PGP and biosynthetic potential. We propose Streptomyces sp. strain DBT204 for inoculums production and development of biofertilizers for enhancing growth of chili and tomato seedlings. Copyright © 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Role for the banana AGAMOUS-like gene MaMADS7 in regulation of fruit ripening and quality.

PubMed

Liu, Juhua; Liu, Lin; Li, Yujia; Jia, Caihong; Zhang, Jianbin; Miao, Hongxia; Hu, Wei; Wang, Zhuo; Xu, Biyu; Jin, Zhiqiang

2015-11-01

MADS-box transcription factors play important roles in organ development. In plants, most studies on MADS-box genes have mainly focused on flower development and only a few concerned fruit development and ripening. A new MADS-box gene named MaMADS7 was isolated from banana fruit by rapid amplification of cDNA ends (RACE) based on a MADS-box fragment obtained from a banana suppression subtractive hybridization (SSH) cDNA library. MaMADS7 is an AGAMOUS-like MADS-box gene that is preferentially expressed in the ovaries and fruits and in tobacco its protein product localizes to the nucleus. This study found that MaMADS7 expression can be induced by exogenous ethylene. Ectopic expression of MaMADS7 in tomato resulted in broad ripening phenotypes. The expression levels of seven ripening and quality-related genes, ACO1, ACS2, E4, E8, PG, CNR and PSY1 in MaMADS7 transgenic tomato fruits were greatly increased while the expression of the AG-like MADS-box gene TAGL1 was suppressed. Compared with the control, the contents of β-carotene, lycopene, ascorbic acid and organic acid in transformed tomato fruits were increased, while the contents of glucose and fructose were slightly decreased. MaMADS7 interacted with banana 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase gene 1 (MaACO1) and tomato phytoene synthase gene (LePSY1) promoters. Our results indicated that MaMADS7 plays an important role in initiating endogenous ethylene biosynthesis and fruit ripening. © 2015 Scandinavian Plant Physiology Society.

TR-DB: an open-access database of compounds affecting the ethylene-induced triple response in Arabidopsis.

PubMed

Hu, Yuming; Callebert, Pieter; Vandemoortel, Ilse; Nguyen, Long; Audenaert, Dominique; Verschraegen, Luc; Vandenbussche, Filip; Van Der Straeten, Dominique

2014-02-01

Small molecules which act as hormone agonists or antagonists represent useful tools in fundamental research and are widely applied in agriculture to control hormone effects. High-throughput screening of large chemical compound libraries has yielded new findings in plant biology, with possible future applications in agriculture and horticulture. To further understand ethylene biosynthesis/signaling and its crosstalk with other hormones, we screened a 12,000 compound chemical library based on an ethylene-related bioassay of dark-grown Arabidopsis thaliana (L.) Heynh. seedlings. From the initial screening, 1313 (∼11%) biologically active small molecules altering the phenotype triggered by the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), were identified. Selection and sorting in classes were based on the angle of curvature of the apical hook, the length and width of the hypocotyl and the root. A MySQL-database was constructed (https://chaos.ugent.be/WE15/) including basic chemical information on the compounds, images illustrating the phenotypes, phenotype descriptions and classification. The research perspectives for different classes of hit compounds will be evaluated, and some general screening tips for customized high-throughput screening and pitfalls will be discussed. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Apoplastic Alkalinization Is Instrumental for the Inhibition of Cell Elongation in the Arabidopsis Root by the Ethylene Precursor 1-Aminocyclopropane-1-Carboxylic Acid1[W][OA

PubMed Central

Staal, Marten; De Cnodder, Tinne; Simon, Damien; Vandenbussche, Filip; Van Der Straeten, Dominique; Verbelen, Jean-Pierre; Elzenga, Theo; Vissenberg, Kris

2011-01-01

In Arabidopsis (Arabidopsis thaliana; Columbia-0) roots, the so-called zone of cell elongation comprises two clearly different domains: the transition zone, a postmeristematic region (approximately 200–450 μm proximal of the root tip) with a low rate of elongation, and a fast elongation zone, the adjacent proximal region (450 μm away from the root tip up to the first root hair) with a high rate of elongation. In this study, the surface pH was measured in both zones using the microelectrode ion flux estimation technique. The surface pH is highest in the apical part of the transition zone and is lowest at the basal part of the fast elongation zone. Fast cell elongation is inhibited within minutes by the ethylene precursor 1-aminocyclopropane-1-carboxylic acid; concomitantly, apoplastic alkalinization occurs in the affected root zone. Fusicoccin, an activator of the plasma membrane H+-ATPase, can partially rescue this inhibition of cell elongation, whereas the inhibitor N,N′-dicyclohexylcarbodiimide does not further reduce the maximal cell length. Microelectrode ion flux estimation experiments with auxin mutants lead to the final conclusion that control of the activity state of plasma membrane H+-ATPases is one of the mechanisms by which ethylene, via auxin, affects the final cell length in the root. PMID:21282405

Gibberellic Acid, Synthetic Auxins, and Ethylene Differentially Modulate α-l-Arabinofuranosidase Activities in Antisense 1-Aminocyclopropane-1-Carboxylic Acid Synthase Tomato Pericarp Discs1

PubMed Central

Sozzi, Gabriel O.; Greve, L. Carl; Prody, Gerry A.; Labavitch, John M.

2002-01-01

α-l-Arabinofuranosidases (α-Afs) are plant enzymes capable of releasing terminal arabinofuranosyl residues from cell wall matrix polymers, as well as from different glycoconjugates. Three different α-Af isoforms were distinguished by size exclusion chromatography of protein extracts from control tomatoes (Lycopersicon esculentum) and an ethylene synthesis-suppressed (ESS) line expressing an antisense 1-aminocyclopropane-1-carboxylic synthase transgene. α-Af I and II are active throughout fruit ontogeny. α-Af I is the first Zn-dependent cell wall enzyme isolated from tomato pericarp tissues, thus suggesting the involvement of zinc in fruit cell wall metabolism. This isoform is inhibited by 1,10-phenanthroline, but remains stable in the presence of NaCl and sucrose. α-Af II activity accounts for over 80% of the total α-Af activity in 10-d-old fruit, but activity drops during ripening. In contrast, α-Af III is ethylene dependent and specifically active during ripening. α-Af I released monosaccharide arabinose from KOH-soluble polysaccharides from tomato cell walls, whereas α-Af II and III acted on Na2CO3-soluble pectins. Different α-Af isoform responses to gibberellic acid, synthetic auxins, and ethylene were followed by using a novel ESS mature-green tomato pericarp disc system. α-Af I and II activity increased when gibberellic acid or 2,4-dichlorophenoxyacetic acid was applied, whereas ethylene treatment enhanced only α-Af III activity. Results suggest that tomato α-Afs are encoded by a gene family under differential hormonal controls, and probably have different in vivo functions. The ESS pericarp explant system allows comprehensive studies involving effects of physiological levels of different growth regulators on gene expression and enzyme activity with negligible wound-induced ethylene production. PMID:12114586

Comparative effectiveness of Pseudomonas and Serratia sp. containing ACC-deaminase for improving growth and yield of wheat (Triticum aestivum L.) under salt-stressed conditions.

PubMed

Zahir, Zahir Ahmad; Ghani, Usman; Naveed, Muhammad; Nadeem, Sajid Mahmood; Asghar, Hafiz Naeem

2009-05-01

Ethylene synthesis is accelerated in response to various environmental stresses like salinity. Ten rhizobacterial strains isolated from wheat rhizosphere taken from different salt affected areas were screened for growth promotion of wheat under axenic conditions at 1, 5, 10 and 15 dS m(-1). Three strains, i.e., Pseudomonas putida (N21), Pseudomonas aeruginosa (N39) and Serratia proteamaculans (M35) showing promising performance under axenic conditions were selected for a pot trial at 1.63 (original), 5, 10 and 15 dS m(-1). Results showed that inoculation was effective even in the presence of higher salinity levels. P. putida was the most efficient strain compared to the other strains and significantly increased the plant height, root length, grain yield, 100-grain weight and straw yield up to 52, 60, 76, 19 and 67%, respectively, over uninoculated control at 15 dS m(-1). Similarly, chlorophyll content and K(+)/Na(+) of leaves also increased by P. putida over control. It is highly likely that under salinity stress, 1-aminocyclopropane-1-carboxylic acid-deaminase activity of these microbial strains might have caused reduction in the synthesis of stress (salt)-induced inhibitory levels of ethylene. The results suggested that these strains could be employed for salinity tolerance in wheat; however, P. putida may have better prospects in stress alleviation/reduction.

Effectiveness of rhizobacteria containing ACC deaminase for growth promotion of peas (Pisum sativum) under drought conditions.

PubMed

Zahir, Z A; Munir, A; Asghar, H N; Shaharoona, B; Arshad, M

2008-05-01

A series of experiments were conducted to assess the effectiveness of rhizobacteria containing 1-aminocyclopropane- 1-carboxylate (ACC) deaminase for growth promotion of peas under drought conditions. Ten rhizobacteria isolated from the rhizosphere of different crops (peas, wheat, and maize) were screened for their growth promoting ability in peas under axenic condition. Three rhizobacterial isolates, Pseudomonas fluorescens biotype G (ACC-5), P. fluorescens (ACC-14), and P. putida biotype A (Q-7), were selected for pot trial on the basis of their source, ACC deaminase activity, root colonization, and growth promoting activity under axenic conditions. Inoculated and uninoculated (control) seeds of pea cultivar 2000 were sown in pots (4 seeds/pot) at different soil moisture levels (25, 50, 75, and 100% of field capacity). Results revealed that decreasing the soil moisture levels from 100 to 25% of field capacity significantly decreased the growth of peas. However, inoculation of peas with rhizobacteria containing ACC deaminase significantly decreased the "drought stress imposed effects" on growth of peas, although with variable efficacy at different moisture levels. At the lowest soil moisture level (25% field capacity), rhizobacterial isolate Pseudomonas fluorescens biotype G (ACC-5) was found to be more promising compared with the other isolates, as it caused maximum increases in fresh weight, dry weight, root length, shoot length, number of leaves per plant, and water use efficiency on fresh and dry weight basis (45, 150, 92, 45, 140, 46, and 147%, respectively) compared with respective uninoculated controls. It is highly likely that rhizobacteria containing ACC deaminase might have decreased the drought-stress induced ethylene in inoculated plants, which resulted in better growth of plants even at low moisture levels. Therefore, inoculation with rhizobacteria containing ACC deaminase could be helpful in eliminating the inhibitory effects of drought stress on the growth of peas.

Nodulation and Delayed Nodule Senescence: Strategies of Two Bradyrhizobium Japonicum Isolates with High Capacity to Fix Nitrogen.

PubMed

López, Silvina M Y; Sánchez, Ma Dolores Molina; Pastorino, Graciela N; Franco, Mario E E; García, Nicolás Toro; Balatti, Pedro A

2018-03-15

The purpose of this work was to study further two Bradyrhizobium japonicum strains with high nitrogen-fixing capacity that were identified within a collection of approximately 200 isolates from the soils of Argentina. Nodulation and nitrogen-fixing capacity and the level of expression of regulatory as well as structural genes of nitrogen fixation and the 1-aminocyclopropane-1-carboxylate (ACC) deaminase gene of the isolates were compared with that of E109-inoculated plants. Both isolates of B. japonicum, 163 and 366, were highly efficient to fix nitrogen compared to commercial strain E109. Isolate 366 developed a higher number and larger biomass of nodules and because of this fixed more nitrogen. Isolate 163 developed the same number and nodule biomass than E109. However, nodules developed by isolate 163 had red interiors for a longer period, had a higher leghemoglobin content, and presented high levels of expression of acdS gene, that codes for an ACC deaminase. In conclusion, naturalized rhizobia of the soils of Argentina hold a diverse population that might be the source of highly active nitrogen-fixing rhizobia, a process that appears to be based on different strategies.

A Ser/Thr protein kinase phosphorylates MA-ACS1 (Musa acuminata 1-aminocyclopropane-1-carboxylic acid synthase 1) during banana fruit ripening.

PubMed

Choudhury, Swarup Roy; Roy, Sujit; Sengupta, Dibyendu N

2012-08-01

1-Aminocyclopropane-1-carboxylic acid synthase (ACS) catalyzes the rate-limiting step in ethylene biosynthesis during ripening. ACS isozymes are regulated both transcriptionally and post-translationally. However, in banana, an important climacteric fruit, little is known about post-translational regulation of ACS. Here, we report the post-translational modification of MA-ACS1 (Musa acuminata ACS1), a ripening inducible isozyme in the ACS family, which plays a key role in ethylene biosynthesis during banana fruit ripening. Immunoprecipitation analyses of phospholabeled protein extracts from banana fruit using affinity-purified anti-MA-ACS1 antibody have revealed phosphorylation of MA-ACS1, particularly in ripe fruit tissue. We have identified the induction of a 41-kDa protein kinase activity in pulp at the onset of ripening. The 41-kDa protein kinase has been identified as a putative protein kinase by MALDI-TOF/MS analysis. Biochemical analyses using partially purified protein kinase fraction from banana fruit have identified the protein kinase as a Ser/Thr family of protein kinase and its possible involvement in MA-ACS1 phosphorylation during ripening. In vitro phosphorylation analyses using synthetic peptides and site-directed mutagenized recombinant MA-ACS1 have revealed that serine 476 and 479 residues at the C-terminal region of MA-ACS1 are phosphorylated. Overall, this study provides important novel evidence for in vivo phosphorylation of MA-ACS1 at the molecular level as a possible mechanism of post-translational regulation of this key regulatory protein in ethylene signaling pathway in banana fruit during ripening.

Copper-tolerant rhizosphere bacteria-characterization and assessment of plant growth promoting factors.

PubMed

Rathi, Manohari; Nandabalan, Yogalakshmi Kadapakkam

2017-04-01

Remediation of heavy metal contaminated soil is a major problem or concern worldwide. Heavy metal accumulation in the soil is increasing day by day by industries, mines, agriculture, fuel combustion and municipal waste discharge. Such contaminated soils harbour a large number of resistant microbial populations. Screening and isolation of such microbes would be utilized for natural remediation of metal contaminated soils. Therefore, in the present study, highly copper-tolerant bacteria from rhizosphere soil of Cynodon dactylon grown in brass effluent contaminated soil were isolated and assessed for plant growth promoting factors. A total of 61 isolates were isolated from the rhizosphere of three contaminated sites. Six highly copper-tolerant isolates named as MYS1, MYS2, MYS3, MYS4, MYS5 and MYS6 were isolated through enrichment in copper containing nutrient broth. 16S rRNA analysis revealed that the isolates were from genera Stenotrophomonas and Brevundimonas and belong to classes Alpha Proteobacteriacea and Gamma Proteobacteriacea, respectively. Strain MYS1, MYS2 and MYS4 showed 95-99% similarity with Stenotrophomonas acidaminiphila, strain MYS3 and MYS5 showed 99 and 97% similarity with Stenotrophomonas maltophilia and Stenotrophomonas sp. Strain MYS6 showed 94% similarity with Brevundimonas diminuta. All the rhizobacteria showed plant growth promoting traits such as production of siderophores, indole acetic acid (IAA), phosphate solubilization and 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity. From this study, we can conclude that all the isolates possess copper resistance and potential for phytoremediation of copper polluted soils.

Investigating the ability of Pseudomonas fluorescens UW4 to reduce cadmium stress in Lactuca sativa via an intervention in the ethylene biosynthetic pathway.

PubMed

Albano, Lucas J; Macfie, Sheila M

2016-12-01

A typical plant response to any biotic or abiotic stress, including cadmium (Cd), involves increased ethylene synthesis, which causes senescence of the affected plant part. Stressed plants can experience reduced ethylene and improved growth if they are inoculated with bacteria that have the enzyme ACC deaminase, which metabolizes the ethylene precursor ACC (1-aminocyclopropane-1-carboxylate). We investigated whether one such bacterium, Pseudomonas fluorescens UW4, reduces the production of ethylene and improves the growth of lettuce (Lactuca sativa) sown in Cd-contaminated potting material (PRO-MIX® BX). Plants were inoculated with the wild-type P. fluorescens UW4 or a mutant strain that cannot produce ACC deaminase. Cadmium-treated plants contained up to 50 times more Cd than did control plants. In noninoculated plants, Cd induced a 5-fold increase in ethylene concentration. The wild-type bacterium prevented Cd-induced reductions in root biomass but there was no relationship between Cd treatment and ethylene production in inoculated plants. In contrast, when the concentration of ethylene was plotted against the extent of bacterial colonization of the roots, increased colonization with wild-type P. fluorescens UW4 was associated with 20% less ethylene production. Ours is the first study to show that the protective effect of this bacterium is proportional to the quantity of bacteria on the root surface.

Role of an Essential Acyl Coenzyme A Carboxylase in the Primary and Secondary Metabolism of Streptomyces coelicolor A3(2)

PubMed Central

Rodríguez, E.; Banchio, C.; Diacovich, L.; Bibb, M. J.; Gramajo, H.

2001-01-01

Two genes, accB and accE, that form part of the same operon, were cloned from Streptomyces coelicolor A3(2). AccB is homologous to the carboxyl transferase domain of several propionyl coezyme A (CoA) carboxylases and acyl-CoA carboxylases (ACCases) of actinomycete origin, while AccE shows no significant homology to any known protein. Expression of accB and accE in Escherichia coli and subsequent in vitro reconstitution of enzyme activity in the presence of the biotinylated protein AccA1 or AccA2 confirmed that AccB was the carboxyl transferase subunit of an ACCase. The additional presence of AccE considerably enhanced the activity of the enzyme complex, suggesting that this small polypeptide is a functional component of the ACCase. The impossibility of obtaining an accB null mutant and the thiostrepton growth dependency of a tipAp accB conditional mutant confirmed that AccB is essential for S. coelicolor viability. Normal growth phenotype in the absence of the inducer was restored in the conditional mutant by the addition of exogenous long-chain fatty acids in the medium, indicating that the inducer-dependent phenotype was specifically related to a conditional block in fatty acid biosynthesis. Thus, AccB, together with AccA2, which is also an essential protein (E. Rodriguez and H. Gramajo, Microbiology 143:3109–3119, 1999), are the most likely components of an ACCase whose main physiological role is the synthesis of malonyl-CoA, the first committed step of fatty acid synthesis. Although normal growth of the conditional mutant was restored by fatty acids, the cultures did not produce actinorhodin or undecylprodigiosin, suggesting a direct participation of this enzyme complex in the supply of malonyl-CoA for the synthesis of these secondary metabolites. PMID:11526020

Trichoderma virens PDR-28: a heavy metal-tolerant and plant growth-promoting fungus for remediation and bioenergy crop production on mine tailing soil.

PubMed

Babu, A Giridhar; Shim, Jaehong; Bang, Keuk-Soo; Shea, Patrick J; Oh, Byung-Taek

2014-01-01

A heavy metal-tolerant fungus, Trichoderma virens PDR-28, was isolated from rhizosphere soil and evaluated for use in remediating mine tailing soil and for plant biomass production. PDR-28 exhibited plant growth-promoting traits, including 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, acid phosphatase and phytase activity, siderophore production, and P solubilization. HMs were more available in mine tailing soil inoculated soil with PDR-28 than in uninoculated soil; the order of HM bioleaching was Cd > As > Zn > Pb > Cu. PDR-28 effectively removed HMs in the order of Pb > Cd > As > Zn > Cu from liquid media containing 100 mg HM L(-1). Inoculating HM-contaminated mine tailing soil with the fungus significantly increased the dry biomass of maize roots (64%) and shoots (56%). Chlorophyll, total soluble sugars (reducible and nonreducible), starch, and protein contents increased by 46%, 28%, 30%, and 29%, respectively, compared to plants grown in uninoculated soil. Inoculation increased heavy metal concentrations in maize roots by 25% (Cu) to 62% (Cd) and in shoots by 35% (Cu) to 64% (Pb) compared to uninoculated plants. Results suggest that PDR-28 would be beneficial for phytostabilization and plant biomass production as a potential source of biofuel in the quest for renewable energy. Copyright © 2013. Published by Elsevier Ltd.

Phosphorylation of 1-Aminocyclopropane-1-Carboxylic Acid Synthase by MPK6, a Stress-Responsive Mitogen-Activated Protein Kinase, Induces Ethylene Biosynthesis in ArabidopsisW⃞

PubMed Central

Liu, Yidong; Zhang, Shuqun

2004-01-01

Mitogen-activated protein kinases (MAPKs) are implicated in regulating plant growth, development, and response to the environment. However, the underlying mechanisms are unknown because of the lack of information about their substrates. Using a conditional gain-of-function transgenic system, we demonstrated that the activation of SIPK, a tobacco (Nicotiana tabacum) stress-responsive MAPK, induces the biosynthesis of ethylene. Here, we report that MPK6, the Arabidopsis thaliana ortholog of tobacco SIPK, is required for ethylene induction in this transgenic system. Furthermore, we found that selected isoforms of 1-aminocyclopropane-1-carboxylic acid synthase (ACS), the rate-limiting enzyme of ethylene biosynthesis, are substrates of MPK6. Phosphorylation of ACS2 and ACS6 by MPK6 leads to the accumulation of ACS protein and, thus, elevated levels of cellular ACS activity and ethylene production. Expression of ACS6DDD, a gain-of-function ACS6 mutant that mimics the phosphorylated form of ACS6, confers constitutive ethylene production and ethylene-induced phenotypes. Increasing numbers of stress stimuli have been shown to activate Arabidopsis MPK6 or its orthologs in other plant species. The identification of the first plant MAPK substrate in this report reveals one mechanism by which MPK6/SIPK regulates plant stress responses. Equally important, this study uncovers a signaling pathway that modulates the biosynthesis of ethylene, an important plant hormone, in plants under stress. PMID:15539472

Sebacina vermifera Promotes the Growth and Fitness of Nicotiana attenuata by Inhibiting Ethylene Signaling1[W

PubMed Central

Barazani, Oz; von Dahl, Caroline C.; Baldwin, Ian T.

2007-01-01

Sebacina vermifera, a growth-promoting endophytic fungus, significantly increases Nicotiana attenuata's growth but impairs both its herbivore resistance and its accumulation of the costly, jasmonic acid (JA)-regulated defense protein, trypsin proteinase inhibitor (TPI). To determine if the fungi's growth-promoting effects can be attributed to lower TPI-related defense costs, we inoculated transformed N. attenuata plants silenced in their ability to synthesize JA, JA-isoleucine, and TPI by antisense (lipoxygenase 3 [as-lox3] and Thr deaminase [as-td]) and inverted repeat (ir-tpi) expression, and found that inoculation promoted plant growth as in untransformed wild-type plants. Moreover, herbivore-elicited increases in JA and JA-isoleucine concentrations did not differ between inoculated and uninoculated wild-type plants. However, inoculation significantly reduced the morphological effect of 1-aminocyclopropane-1-carboxylic acid on wild-type seedlings in a triple response assay, suggesting that ethylene signaling was impaired. Furthermore, S. vermifera failed to promote the growth of N. attenuata plants transformed to silence ethylene production (1-aminocyclopropane-1-carboxylic acid oxidase [ir-aco]). Inoculating wild-type plants with S. vermifera decreased the ethylene burst elicited by applying Manduca sexta oral secretions to mechanical wounds. Accordingly, oral secretion-elicited transcript levels of the ethylene synthesis genes NaACS3, NaACO1, and NaACO3 in inoculated plants were significantly lower compared to these levels in uninoculated wild-type plants. Inoculation accelerated germination in wild-type seeds; however, uninoculated wild-type seeds germinated as rapidly as inoculated seeds in the presence of the ethylene scrubber KMnO4. In contrast, neither inoculation nor KMnO4 exposure influenced the germination of ir-aco seeds. We conclude that S. vermifera increases plant growth by impairing ethylene production independently of JA signaling and TPI production. PMID:17416638

Cyclic RGD peptidomimetics containing 4- and 5-amino-cyclopropane pipecolic acid (CPA) templates as dual αVβ3 and α5β1 integrin ligands.

PubMed

Sernissi, Lorenzo; Trabocchi, Andrea; Scarpi, Dina; Bianchini, Francesca; Occhiato, Ernesto G

2016-02-15

4-Amino- and 5-amino-cyclopropane pipecolic acids (CPAs) with cis relative stereochemistry between the carboxylic and amino groups were used as templates to prepare cyclic peptidomimetics containing the RGD sequence as possible integrin binders. The peptidomimetic c(RGD8) built on the 5-amino-CPA displayed an inhibition activity (IC50=2.4nM) toward the αvβ3 integrin receptor (expressed in M21 human melanoma cell line) comparable to that of the most potent antagonists reported so far and it was ten times more active than the corresponding antagonist c(RGD7) derived from the isomeric 4-amino-CPA. Both compounds were also nanomolar ligands of the α5β1 integrin (expressed in human erythroleukemia cell line K562). These results suggest that the CPA-derived templates are suitable for the preparation of dual αvβ3 and α5β1 ligands to suppress integrin-mediated events as well as for targeted drug delivery in cancer therapy. Copyright © 2015 Elsevier Ltd. All rights reserved.

Expression of the patatin-related phospholipase A gene AtPLA IIA in Arabidopsis thaliana is up-regulated by salicylic acid, wounding, ethylene, and iron and phosphate deficiency.

PubMed

Rietz, Steffen; Holk, André; Scherer, Günther F E

2004-09-01

In Arabidopsis thaliana (L.) Heynh., the cytosolic, patatin-related phospholipase A enzymes comprise a family of ten genes designated AtPLAs thought to be involved in auxin and pathogen signalling [A. Holk et al. (2002) Plant Physiol 130:90-101]. One of these, AtPLA IIA, is investigated here by studying its transcriptional regulation through transgenic Arabidopsis plants containing the AtPLA IIA promoter (PIIA) fused to the beta-glucuronidase (GUS) gene. GUS activity appeared in leaves at 10-12 days and became increasingly stronger with age in all leaves. From the same age on, strong GUS activity was visible in the basal stipules of the rosette leaves. PIIA-dependent GUS activity was found in the older parts of the primary root (from 10 days on) and, later in development, in older parts of side roots, and the root cap. No GUS activity was detected in flower organs. PIIA-dependent GUS expression in 12-day-old plants was up-regulated after treatment by salicylic acid, Bion, wounding, 1-aminocyclopropane-1-carboxylic acid (ACC) and jasmonic acid. When transgenic PIIA:: uidA plants were grown devoid of iron, 9-day-old plants exhibited increased GUS activity in the leaves and, when devoid of phosphate, 11-day-old plants had increased GUS activity in the roots. In conclusion, this member of the patatin-related phospholipase A gene family showed properties of a defence and iron-stress and phosphate-stress gene, being transcriptionally up-regulated within hours or days.

The hyperaccumulator Sedum plumbizincicola harbors metal-resistant endophytic bacteria that improve its phytoextraction capacity in multi-metal contaminated soil.

PubMed

Ma, Ying; Oliveira, Rui S; Nai, Fengjiao; Rajkumar, Mani; Luo, Yongming; Rocha, Inês; Freitas, Helena

2015-06-01

Endophyte-assisted phytoremediation has recently been suggested as a successful approach for ecological restoration of metal contaminated soils, however little information is available on the influence of endophytic bacteria on the phytoextraction capacity of metal hyperaccumulating plants in multi-metal polluted soils. The aims of our study were to isolate and characterize metal-resistant and 1-aminocyclopropane-1-carboxylate (ACC) utilizing endophytic bacteria from tissues of the newly discovered Zn/Cd hyperaccumulator Sedum plumbizincicola and to examine if these endophytic bacterial strains could improve the efficiency of phytoextraction of multi-metal contaminated soils. Among a collection of 42 metal resistant bacterial strains isolated from the tissues of S. plumbizincicola grown on Pb/Zn mine tailings, five plant growth promoting endophytic bacterial strains (PGPE) were selected due to their ability to promote plant growth and to utilize ACC as the sole nitrogen source. The five isolates were identified as Bacillus pumilus E2S2, Bacillus sp. E1S2, Bacillus sp. E4S1, Achromobacter sp. E4L5 and Stenotrophomonas sp. E1L and subsequent testing revealed that they all exhibited traits associated with plant growth promotion, such as production of indole-3-acetic acid and siderophores and solubilization of phosphorus. These five strains showed high resistance to heavy metals (Cd, Zn and Pb) and various antibiotics. Further, inoculation of these ACC utilizing strains significantly increased the concentrations of water extractable Cd and Zn in soil. Moreover, a pot experiment was conducted to elucidate the effects of inoculating metal-resistant ACC utilizing strains on the growth of S. plumbizincicola and its uptake of Cd, Zn and Pb in multi-metal contaminated soils. Out of the five strains, B. pumilus E2S2 significantly increased root (146%) and shoot (17%) length, fresh (37%) and dry biomass (32%) of S. plumbizincicola as well as plant Cd uptake (43%), whereas Bacillus sp. E1S2 significantly enhanced the accumulation of Zn (18%) in plants compared with non-inoculated controls. The inoculated strains also showed high levels of colonization in rhizosphere and plant tissues. Results demonstrate the potential to improve phytoextraction of soils contaminated with multiple heavy metals by inoculating metal hyperaccumulating plants with their own selected functional endophytic bacterial strains. Copyright © 2015 Elsevier Ltd. All rights reserved.

Rhizosphere bacteria of Costularia spp. from ultramafic soils in New Caledonia: diversity, tolerance to extreme edaphic conditions, and role in plant growth and mineral nutrition.

PubMed

Gonin, Mathieu; Gensous, Simon; Lagrange, Alexandre; Ducousso, Marc; Amir, Hamid; Jourand, Philippe

2013-03-01

Rhizosphere bacteria were isolated from Costularia spp., pioneer sedges from ultramafic soils in New Caledonia, which is a hotspot of biodiversity in the South Pacific. Genus identification, ability to tolerate edaphic constraints, and plant-growth-promoting (PGP) properties were analysed. We found that 10(5) colony-forming units per gram of root were dominated by Proteobacteria (69%) and comprised 21 genera, including Burkholderia (28%), Curtobacterium (15%), Bradyrhizobium (9%), Sphingomonas (8%), Rhizobium (7%), and Bacillus (5%). High proportions of bacteria tolerated many elements of the extreme edaphic conditions: 82% tolerated 100 μmol·L(-1) chromium, 70% 1 mmol·L(-1) nickel, 63% 10 mmol·L(-1) manganese, 24% 1 mmol·L(-1) cobalt, and 42% an unbalanced calcium/magnesium ratio (1/16). These strains also exhibited multiple PGP properties, including the ability to produce ammonia (65%), indole-3-acetic acid (60%), siderophores (52%), and 1-aminocyclopropane-1-carboxylate (ACC) deaminase (39%); as well as the capacity to solubilize phosphates (19%). The best-performing strains were inoculated with Sorghum sp. grown on ultramafic substrate. Three strains significantly enhanced the shoot biomass by up to 33%. The most successful strains influenced plant nutrition through the mobilization of metals in roots and a reduction of metal transfer to shoots. These results suggest a key role of these bacteria in plant growth, nutrition, and adaptation to the ultramafic constraints.

Effect of heavy metals on acdS gene expression in Herbaspirillium sp. GW103 isolated from rhizosphere soil.

PubMed

Loganathan, Praburaman; Myung, Hyun; Muthusamy, Govarthanan; Lee, Kui-Jae; Seralathan, Kamala-Kannan; Oh, Byung-Taek

2015-10-01

This study aimed to understand the influence of heavy metals on 1-aminocyclopropane-1-carboxylate deaminase activity (ACCD) and acdS gene expression in Herbaspirillium sp. GW103. The GW103 strain ACCD activity decreased in cells grown in a medium supplemented with Pb and As, whereas cells grown in medium supplemented with Cu showed increase in enzyme activity. The GW103 strain produced 262.2 ± 6.17 μmol of α-ketobutyrate per milligram of protein per hour during ACC deamination at 25 °C after 24 h incubation. Using a PCR approach, an acdS coding-gene of 1.06 kbp was amplified in isolate GW103, showing 92% identity with Herbaspirillum seropedicae SmR1 acdS gene. Real time quantitative polymerase chain reaction results indicate that the acdS expression rate was increased (7.1-fold) in the presence of Cu, whereas it decreased (0.2- and 0.1-fold) in the presence of As and Pb. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Drought response of Mucuna pruriens (L.) DC. inoculated with ACC deaminase and IAA producing rhizobacteria.

PubMed

Saleem, Aansa Rukya; Brunetti, Cecilia; Khalid, Azeem; Della Rocca, Gianni; Raio, Aida; Emiliani, Giovanni; De Carlo, Anna; Mahmood, Tariq; Centritto, Mauro

2018-01-01

Drought is one of the major constraints limiting agricultural production worldwide and is expected to increase in the future. Limited water availability causes significant effects to plant growth and physiology. Plants have evolved different traits to mitigate the stress imposed by drought. The presence of plant growth-promoting rhizobacteria (PGPR) could play an important role in improving plant performances and productivity under drought. These beneficial microorganisms colonize the rhizosphere of plants and increase drought tolerance by lowering ethylene formation. In the present study, we demonstrate the potential to improve the growth of velvet bean under water deficit conditions of two different strains of PGPR with ACCd (1-Aminocyclopropane-1-Carboxylate deaminase) activity isolated from rainfed farming system. We compared uninoculated and inoculated plants with PGPR to assess: a) photosynthetic performance and biomass; b) ACC content and ethylene emission from leaves and roots; c) leaf isoprene emission. Our results provided evidence that under drought conditions inoculation with PGPR containing the ACCd enzyme could improve plant growth compared to untreated plants. Ethylene emission from roots and leaves of inoculated velvet bean plants was significantly lower than uninoculated plants. Moreover, isoprene emission increased with drought stress progression and was higher in inoculated plants compared to uninoculated counterparts. These findings clearly illustrate that selected PGPR strains isolated from rainfed areas could be highly effective in promoting plant growth under drought conditions by decreasing ACC and ethylene levels in plants.

Drought response of Mucuna pruriens (L.) DC. inoculated with ACC deaminase and IAA producing rhizobacteria

PubMed Central

Khalid, Azeem; Raio, Aida; Emiliani, Giovanni; De Carlo, Anna; Mahmood, Tariq

2018-01-01

Drought is one of the major constraints limiting agricultural production worldwide and is expected to increase in the future. Limited water availability causes significant effects to plant growth and physiology. Plants have evolved different traits to mitigate the stress imposed by drought. The presence of plant growth-promoting rhizobacteria (PGPR) could play an important role in improving plant performances and productivity under drought. These beneficial microorganisms colonize the rhizosphere of plants and increase drought tolerance by lowering ethylene formation. In the present study, we demonstrate the potential to improve the growth of velvet bean under water deficit conditions of two different strains of PGPR with ACCd (1-Aminocyclopropane-1-Carboxylate deaminase) activity isolated from rainfed farming system. We compared uninoculated and inoculated plants with PGPR to assess: a) photosynthetic performance and biomass; b) ACC content and ethylene emission from leaves and roots; c) leaf isoprene emission. Our results provided evidence that under drought conditions inoculation with PGPR containing the ACCd enzyme could improve plant growth compared to untreated plants. Ethylene emission from roots and leaves of inoculated velvet bean plants was significantly lower than uninoculated plants. Moreover, isoprene emission increased with drought stress progression and was higher in inoculated plants compared to uninoculated counterparts. These findings clearly illustrate that selected PGPR strains isolated from rainfed areas could be highly effective in promoting plant growth under drought conditions by decreasing ACC and ethylene levels in plants. PMID:29447189

Ethylene and nitric oxide interact to regulate the magnesium deficiency-induced root hair development in Arabidopsis.

PubMed

Liu, Miao; Liu, Xing Xing; He, Xiao Lin; Liu, Li Juan; Wu, Hao; Tang, Cai Xian; Zhang, Yong Song; Jin, Chong Wei

2017-02-01

Nitric oxide (NO) and ethylene respond to biotic and abiotic stresses through either similar or independent processes. This study examines the mechanism underlying the effects of NO and ethylene on promoting root hair development in Arabidopsis under magnesium (Mg) deficiency. The interaction between NO and ethylene in the regulation of Mg deficiency-induced root hair development was investigated using NO- and ethylene-related mutants and pharmacological methods. Mg deficiency triggered a burst of NO and ethylene, accompanied by a stimulated development of root hairs. Interestingly, ethylene facilitated NO generation by activation of both nitrate reductase and nitric oxide synthase-like (NOS-L) in the roots of Mg-deficient plants. In turn, NO enhanced ethylene synthesis through stimulating the activities of 1-aminocyclopropane-1-carboxylate (ACC) oxidase and ACC synthase (ACS). These two processes constituted an NO-ethylene feedback loop. Blocking either of these two processes inhibited the stimulation of root hair development under Mg deficiency. In conclusion, we suggest that Mg deficiency increases the production of NO and ethylene in roots, each influencing the accumulation and role of the other, and thus these two signals interactively regulate Mg deficiency-induced root hair morphogenesis. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Identification of genes involved in the ACC-mediated control of root cell elongation in Arabidopsis thaliana

PubMed Central

2012-01-01

Background Along the root axis of Arabidopsis thaliana, cells pass through different developmental stages. In the apical meristem repeated cycles of division increase the numbers of cells. Upon leaving the meristem, these cells pass the transition zone where they are physiologically and mechanically prepared to undergo subsequent rapid elongation. During the process of elongation epidermal cells increase their length by 300% in a couple of hours. When elongation ceases, the cells acquire their final size, shape and functions (in the differentiation zone). Ethylene administered as its precursor 1-aminocyclopropane-1-carboxylic acid (ACC) is capable of inhibiting elongation in a concentration-dependent way. Using a microarray analysis, genes and/or processes involved in this elongation arrest are identified. Results Using a CATMA-microarray analysis performed on control and 3h ACC-treated roots, 240 differentially expressed genes were identified. Quantitative Real-Time RT-PCR analysis of the 10 most up and down regulated genes combined with literature search confirmed the accurateness of the analysis. This revealed that inhibition of cell elongation is, at least partly, caused by restricting the events that under normal growth conditions initiate elongation and by increasing the processes that normally stop cellular elongation at the end of the elongation/onset of differentiation zone. Conclusions ACC interferes with cell elongation in the Arabidopsis thaliana roots by inhibiting cells from entering the elongation process and by immediately stimulating the formation of cross-links in cell wall components, diminishing the remaining elongation capacity. From the analysis of the differentially expressed genes, it becomes clear that many genes identified in this response, are also involved in several other kind of stress responses. This suggests that many responses originate from individual elicitors, but that somewhere in the downstream signaling cascade, these are converged to a ’common pathway’. Furthermore, several potential keyplayers, such as transcription factors and auxin-responsive genes, were identified by the microarray analysis. They await further analysis to reveal their exact role in the control of cell elongation. PMID:23134674

Expression of a nitric oxide degrading enzyme induces a senescence programme in Arabidopsis.

PubMed

Mishina, Tatiana E; Lamb, Chris; Zeier, Jürgen

2007-01-01

Nitric oxide (NO) has been proposed to act as a factor delaying leaf senescence and fruit maturation in plants. Here we show that expression of a NO degrading dioxygenase (NOD) in Arabidopsis thaliana initiates a senescence-like phenotype, an effect that proved to be more pronounced in older than in younger leaves. This senescence phenotype was preceded by a massive switch in gene expression in which photosynthetic genes were down-regulated, whereas many senescence-associated genes (SAGs) and the 1-aminocyclopropane-1-carboxylic acid (ACC) synthase gene ACS6 involved in ethylene synthesis were up-regulated. External fumigation of NOD plants with NO as well as environmental conditions known to stimulate endogenous NO production attenuated the induced senescence programme. For instance, both high light conditions and nitrate feeding reduced the senescence phenotype and attenuated the down-regulation of photosynthetic genes as well as the up-regulation of SAGs. Treatment of plants with the cytokinin 6-benzylaminopurin (BAP) reduced the down-regulation of photosynthesis, although it had no consistent effect on SAG expression. Metabolic changes during NOD-induced senescence comprehended increases in salicylic acid (SA) levels, accumulation of the phytoalexin camalexin and elevation of leaf gamma-tocopherol contents, all of which occurred during natural senescence in Arabidopsis leaves as well. Moreover, NO fumigation delayed the senescence process induced by darkening individual Arabidopsis Columbia-0 (Col-0) leaves. Our data thus support the notion that NO acts as a negative regulator of leaf senescence.

Phytohormone Signaling of the Resistance to Plum pox virus (PPV, Sharka Disease) Induced by Almond (Prunus dulcis (Miller) Webb) Grafting to Peach (P. persica L. Batsch).

PubMed

Dehkordi, Azam Nikbakht; Rubio, Manuel; Babaeian, Nadali; Albacete, Alfonso; Martínez-Gómez, Pedro

2018-05-03

Plum pox virus (PPV, sharka) is a limiting factor for peach production, and no natural sources of resistance have been described. Recent studies, however, have demonstrated that grafting the almond cultivar "Garrigues" onto the "GF305" peach infected with Dideron-type (PPV-D) isolates progressively reduces disease symptoms and virus accumulation. Furthermore, grafting "Garrigues" onto "GF305" prior to PPV-D inoculation has been found to completely prevent virus infection, showing that resistance is constitutive and not induced by the virus. To unravel the phytohormone signaling of this mechanism, we analyzed the following phytohormones belonging to the principal hormone classes: the growth-related phytohormones cytokinin trans-zeatin (tZ) and the gibberellins GA₃ and GA₄; and the stress-related phytohormones ethylene acid precursor 1-aminocyclopropane-1-carboxylic acid (ACC), abscisic acid (ABA), salicylic acid (SA), and jasmonic acid (JA). PPV inoculation produced a significant increase in GA₃ and ABA in peach, and these imbalances were related to the presence of chlorosis symptoms. However, grafting "Garrigues" almond onto the PPV-inoculated "GF305" peach produced the opposite effect, reducing GA₃ and ABA contents in parallel to the elimination of symptoms. Our results showed the significant implication of SA in this induced resistance in peach with an additional effect on tZ and JA concentrations. This SA-induced resistance based in the decrease in symptoms seems to be different from Systemic Acquired Resistance (SAR) and Induced Systemic Resistance (ISR), which are based in other reactions producing necrosis. Further studies are necessary, however, to validate these results against PPV-D isolates in the more aggressive Marcus-type (PPV-M) isolates.

An Ethylene-Protected Achilles’ Heel of Etiolated Seedlings for Arthropod Deterrence

PubMed Central

Boex-Fontvieille, Edouard; Rustgi, Sachin; von Wettstein, Diter; Pollmann, Stephan; Reinbothe, Steffen; Reinbothe, Christiane

2016-01-01

A small family of Kunitz protease inhibitors exists in Arabidopsis thaliana, a member of which (encoded by At1g72290) accomplishes highly specific roles during plant development. Arabidopsis Kunitz-protease inhibitor 1 (Kunitz-PI;1), as we dubbed this protein here, is operative as cysteine PI. Activity measurements revealed that despite the presence of the conserved Kunitz-motif the bacterially expressed Kunitz-PI;1 was unable to inhibit serine proteases such as trypsin and chymotrypsin, but very efficiently inhibited the cysteine protease RESPONSIVE TO DESICCATION 21. Western blotting and cytolocalization studies using mono-specific antibodies recalled Kunitz-PI;1 protein expression in flowers, young siliques and etiolated seedlings. In dark-grown seedlings, maximum Kunitz-PI;1 promoter activity was detected in the apical hook region and apical parts of the hypocotyls. Immunolocalization confirmed Kunitz-PI;1 expression in these organs and tissues. No transmitting tract (NTT) and HECATE 1 (HEC1), two transcription factors previously implicated in the formation of the female reproductive tract in flowers of Arabidopsis, were identified to regulate Kunitz-PI;1 expression in the dark and during greening, with NTT acting negatively and HEC1 acting positively. Laboratory feeding experiments with isopod crustaceans such as Porcellio scaber (woodlouse) and Armadillidium vulgare (pillbug) pinpointed the apical hook as ethylene-protected Achilles’ heel of etiolated seedlings. Because exogenous application of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) and mechanical stress (wounding) strongly up-regulated HEC1-dependent Kunitz-PI;1 gene expression, our results identify a new circuit controlling herbivore deterrence of etiolated plants in which Kunitz-PI;1 is involved. PMID:27625656

Exogenously induced expression of ethylene biosynthesis, ethylene perception, phospholipase D, and Rboh-oxidase genes in broccoli seedlings

PubMed Central

Jakubowicz, Małgorzata; Gałgańska, Hanna; Nowak, Witold; Sadowski, Jan

2010-01-01

In higher plants, copper ions, hydrogen peroxide, and cycloheximide have been recognized as very effective inducers of the transcriptional activity of genes encoding the enzymes of the ethylene biosynthesis pathway. In this report, the transcriptional patterns of genes encoding the 1-aminocyclopropane-1-carboxylate synthases (ACSs), 1-aminocyclopropane-1-carboxylate oxidases (ACOs), ETR1, ETR2, and ERS1 ethylene receptors, phospholipase D (PLD)-α1, -α2, -γ1, and -δ, and respiratory burst oxidase homologue (Rboh)-NADPH oxidase-D and -F in response to these inducers in Brassica oleracea etiolated seedlings are shown. ACS1, ACO1, ETR2, PLD-γ1, and RbohD represent genes whose expression was considerably affected by all of the inducers used. The investigations were performed on the seedlings with (i) ethylene insensitivity and (ii) a reduced level of the PLD-derived phosphatidic acid (PA). The general conclusion is that the expression of ACS1, -3, -4, -5, -7, and -11, ACO1, ETR1, ERS1, and ETR2, PLD-γ 1, and RbohD and F genes is undoubtedly under the reciprocal cross-talk of the ethylene and PAPLD signalling routes; both signals affect it in concerted or opposite ways depending on the gene or the type of stimuli. The results of these studies on broccoli seedlings are in agreement with the hypothesis that PA may directly affect the ethylene signal transduction pathway via an inhibitory effect on CTR1 (constitutive triple response 1) activity. PMID:20581125

Penicillium expansum (compatible) and Penicillium digitatum (non-host) pathogen infection differentially alter ethylene biosynthesis in apple fruit.

PubMed

Vilanova, Laura; Vall-Llaura, Núria; Torres, Rosario; Usall, Josep; Teixidó, Neus; Larrigaudière, Christian; Giné-Bordonaba, Jordi

2017-11-01

The role of ethylene on inducing plant resistance or susceptibility to certain fungal pathogens clearly depends on the plant pathogen interaction with little or no-information available focused on the apple-Penicillium interaction. Taken advantage that Penicillium expansum is the compatible pathogen and P. digitatum is the non-host of apples, the present study aimed at deciphering how each Penicillium spp. could interfere in the fruit ethylene biosynthesis at the biochemical and molecular level. The infection capacity and different aspects related to the ethylene biosynthesis were conducted at different times post-inoculation. The results show that the fruit ethylene biosynthesis was differently altered during the P. expansum infection than in response to other biotic (non-host pathogen P. digitatum) or abiotic stresses (wounding). The first symptoms of the disease due to P. expansum were visible before the initiation of the fruit ethylene climacteric burst. Indeed, the ethylene climacteric burst was reduced in response to P. expansum concomitant to an important induction of MdACO3 gene expression and an inhibition (ca. 3-fold) and overexpression (ca. 2-fold) of ACO (1-Aminocyclopropane-1-carboxylic acid oxidase) and ACS (1-Aminocyclopropane-1-carboxylic acid synthase) enzyme activities, indicating a putative role of MdACO3 in the P. expansum-apple interaction which may, in turn, be related to System-1 ethylene biosynthesis. System-1 is auto-inhibited by ethylene and is characteristic of non-climateric or pre-climacteric fruit. Accordingly, we hypothesise that P. expansum may 'manipulate' the endogenous ethylene biosynthesis in apples, leading to the circumvention or suppression of effective defences hence facilitating its colonization. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Foliar Abscisic Acid-To-Ethylene Accumulation and Response Regulate Shoot Growth Sensitivity to Mild Drought in Wheat

PubMed Central

Valluru, Ravi; Davies, William J.; Reynolds, Matthew P.; Dodd, Ian C.

2016-01-01

Although, plant hormones play an important role in adjusting growth in response to environmental perturbation, the relative contributions of abscisic acid (ABA) and ethylene remain elusive. Using six spring wheat genotypes differing for stress tolerance, we show that young seedlings of the drought-tolerant (DT) group maintained or increased shoot dry weight (SDW) while the drought-susceptible (DS) group decreased SDW in response to mild drought. Both the DT and DS groups increased endogenous ABA and ethylene concentrations under mild drought compared to control. The DT and DS groups exhibited different SDW response trends, whereby the DS group decreased while the DT group increased SDW, to increased concentrations of ABA and ethylene under mild drought, although both groups decreased ABA/ethylene ratio under mild drought albeit at different levels. We concluded that SDW of the DT and DS groups might be distinctly regulated by specific ABA:ethylene ratio. Further, a foliar-spray of low concentrations (0.1 μM) of ABA increased shoot relative growth rate (RGR) in the DS group while ACC (1-aminocyclopropane-1-carboxylic acid, ethylene precursor) spray increased RGR in both groups compared to control. Furthermore, the DT group accumulated a significantly higher galactose while a significantly lower maltose in the shoot compared to the DS group. Taken all together, these results suggest an impact of ABA, ethylene, and ABA:ethylene ratio on SDW of wheat seedlings that may partly underlie a genotypic variability of different shoot growth sensitivities to drought among crop species under field conditions. We propose that phenotyping based on hormone accumulation, response and hormonal ratio would be a viable, rapid, and an early–stage selection tool aiding genotype selection for stress tolerance. PMID:27148292

The novel ethylene-responsive factor CsERF025 affects the development of fruit bending in cucumber.

PubMed

Wang, Chunhua; Xin, Ming; Zhou, Xiuyan; Liu, Chunhong; Li, Shengnan; Liu, Dong; Xu, Yuan; Qin, Zhiwei

2017-11-01

Overexpression of CsERF025 induces fruit bending by promoting the production of ethylene. Cucumber fruit bending critically affects cucumber quality, but the mechanism that causes fruit bending remains unclear. To better understand this mechanism, we performed transcriptome analyses on tissues from the convex (C1) and concave (C2) sides of bending and straight (S) fruit at 2 days post anthesis (DPA). We identified a total of 281 differentially expressed genes (DEGs) from both the convex and concave sides of bent fruit that showed significantly different expression profiles relative to straight fruits. Of these 281 DEGs, 196 were up-regulated (C1/S_C2/S) and 85 were down-regulated (C1/S_C2/S). Among the 196 up-regulated DEGs, the transcriptional levels of genes related to ethylene biosynthesis and signaling pathways were significantly higher in bending fruit compared with straight fruit. CsERF025 showed the largest difference in expression between bending and straight fruit. CsERF025 is an AP2/ERF gene encoding a protein that localizes to the nucleus. Overexpression of this gene increased the bending rate of cucumber fruits and increased the angle of bending. CsERF025 increased both the expression of ethylene biosynthesis-related genes and the production of ethylene. The application of exogenous 1-aminocyclopropane-l-carboxylic acid (ACC) to straight fruits from control plants promoted fruit bending. Thus, CsERF025 enhances the production of ethylene and thereby promotes fruit bending in cucumber.

Trichoderma-Plant Root Colonization: Escaping Early Plant Defense Responses and Activation of the Antioxidant Machinery for Saline Stress Tolerance

PubMed Central

Brotman, Yariv; Landau, Udi; Cuadros-Inostroza, Álvaro; Takayuki, Tohge; Fernie, Alisdair R.; Chet, Ilan; Viterbo, Ada; Willmitzer, Lothar

2013-01-01

Trichoderma spp. are versatile opportunistic plant symbionts which can colonize the apoplast of plant roots. Microarrays analysis of Arabidopsis thaliana roots inoculated with Trichoderma asperelloides T203, coupled with qPCR analysis of 137 stress responsive genes and transcription factors, revealed wide gene transcript reprogramming, proceeded by a transient repression of the plant immune responses supposedly to allow root colonization. Enhancement in the expression of WRKY18 and WRKY40, which stimulate JA-signaling via suppression of JAZ repressors and negatively regulate the expression of the defense genes FMO1, PAD3 and CYP71A13, was detected in Arabidopsis roots upon Trichoderma colonization. Reduced root colonization was observed in the wrky18/wrky40 double mutant line, while partial phenotypic complementation was achieved by over-expressing WRKY40 in the wrky18 wrky40 background. On the other hand increased colonization rate was found in roots of the FMO1 knockout mutant. Trichoderma spp. stimulate plant growth and resistance to a wide range of adverse environmental conditions. Arabidopsis and cucumber (Cucumis sativus L.) plants treated with Trichoderma prior to salt stress imposition show significantly improved seed germination. In addition, Trichoderma treatment affects the expression of several genes related to osmo-protection and general oxidative stress in roots of both plants. The MDAR gene coding for monodehydroascorbate reductase is significantly up-regulated and, accordingly, the pool of reduced ascorbic acid was found to be increased in Trichoderma treated plants. 1-Aminocyclopropane-1-carboxylate (ACC)-deaminase silenced Trichoderma mutants were less effective in providing tolerance to salt stress, suggesting that Trichoderma, similarly to ACC deaminase producing bacteria, can ameliorate plant growth under conditions of abiotic stress, by lowering ameliorating increases in ethylene levels as well as promoting an elevated antioxidative capacity. PMID:23516362

Acetyl-CoA carboxylase-a as a novel target for cancer therapy.

PubMed

Wang, Chun; Rajput, Sandeep; Watabe, Kounosuke; Liao, Duan-Fang; Cao, Deliang

2010-01-01

Acetyl-CoA carboxylases (ACC) are rate-limiting enzymes in de novo fatty acid synthesis, catalyzing ATP-dependent carboxylation of acetyl-CoA to form malonyl-CoA. Malonyl-CoA is a critical bi-functional molecule, i.e., a substrate of fatty acid synthase (FAS) for acyl chain elongation (fatty acid synthesis) and an inhibitor of carnitine palmitoyltransferase I (CPT-I) for fatty acid beta-oxidation. Two ACC isoforms have been identified in mammals, i.e. ACC-alpha (ACCA, also termed ACC1) and ACC-beta (ACCB, also designated ACC2). ACC has long been used as a target for the management of metabolic diseases, such as obesity and metabolic syndrome, and various inhibitors have been developed in clinical trials. Recently, ACCA up-regulation has been recognized in multiple human cancers, promoting lipogenesis to meet the need of cancer cells for rapid growth and proliferation. Therefore, ACCA might be effective as a potent target for cancer intervention, and the inhibitors developed for the treatment of metabolic diseases would be potential therapeutic agents for cancer therapy. This review summarizes our recent findings and updates the current understanding of the ACCA with focus on cancer research.

Plant growth-promoting bacteria facilitate the growth of barley and oats in salt-impacted soil: implications for phytoremediation of saline soils.

PubMed

Chang, Pearl; Gerhardt, Karen E; Huang, Xiao-Dong; Yu, Xiao-Ming; Glick, Bernard R; Gerwing, Perry D; Greenberg, Bruce M

2014-01-01

Plant growth-promoting bacteria (PGPB) strains that contain the enzyme 1-amino-cyclopropane-1-carboxylate (ACC) deaminase can lower stress ethylene levels and improve plant growth. In this study, ACC deaminase-producing bacteria were isolated from a ) salt-impacted ( 50 dS/m) farm field, and their ability to promote plant growth of barley 1): and oats in saline soil was investigated in pouch assays (1% NaCI), greenhouse trials (9.4 dS/m), and field trials (6-24 dS/m). A mix of previously isolated PGPB strains UW3 (Pseudomonas sp.) and UW4 (P. sp.) was also tested for comparison. Rhizobacterial isolate CMH3 (P. corrugata) and UW3+UW4 partially alleviated plant salt stress in growth pouch assays. In greenhouse trials, CMH3 enhanced root biomass of barley and oats by 200% and 50%, respectively. UW3+UW4, CMH3 and isolate CMH2 also enhanced barley and oat shoot growth by 100%-150%. In field tests, shoot biomass of oats tripled when treated with UW3+UW4 and doubled with CHM3 compared with that of untreated plants. PGPB treatment did not affect salt uptake on a per mass basis; higher plant biomass led to greater salt uptake, resulting in decreased soil salinity. This study demonstrates a method for improving plant growth in marginal saline soils. Associated implications for salt

Various effects of fluorescent bacteria of the genus Pseudomonas containing ACC deaminase on wheat seedling growth.

PubMed

Magnucka, Elżbieta G; Pietr, Stanisław J

2015-12-01

The study evaluates the effect of rhizobacteria having 1-aminocyclopropane-1-carboxylate deaminase (ACCd) on the development of wheat seedlings. This enzyme has been proposed to play a key role in microbe-plant association. Three fluorescent pseudomonads containing this deaminase were selected from 70 strains of pseudomonads isolated from rhizosphere of wheat (Triticum aestivum L.) and rape (Brassica napus L.). These bacteria, varied significantly in the ability to both biosynthesize auxins and hydrolyze ACC. Among them, Pseudomonas brassicacearum subsp. brassicacearum strain RZ310 presented the highest activities of ACC deaminase during 96h of growth in liquid Dworkin and Foster (DF) salt medium. Additionally, this rape rhizosphere strain did not produce indoles. Two other isolates, Pseudomonas sp. PO283 and Pseudomonas sp. PO366, secreted auxins only in the presence of their precursor. Phylogenetic analysis of the 16S rRNA gene and four other protein-encoding genes indicated that these wheat rhizosphere isolates belonged to the fluorescent Pseudomonas group. Moreover, the effects of these strains on wheat seedling growth under in vitro conditions were markedly dependent on both their cell suspensions used to grain inoculation and nutrient conditions. Strains tested had beneficial influence on wheat seedlings mainly at low cell densities. In addition, access to nutrients markedly changed bacteria action on cereal growth. Their presence generally favored the positive effects of pseudomonads on length and the estimated biomasses of wheat coleoptiles. Despite these general rules, impacts of each isolate on the growth parameters of cereal seedlings were unique. Copyright © 2015 Elsevier GmbH. All rights reserved.

Comparative effectiveness of ACC-deaminase and/or nitrogen-fixing rhizobacteria in promotion of maize (Zea mays L.) growth under lead pollution.

PubMed

Hassan, Waseem; Bano, Rizwana; Bashir, Farhat; David, Julie

2014-09-01

Lead (Pb) pollution is appearing as an alarming threat nowadays. Excessive Pb concentrations in agricultural soils result in minimizing the soil fertility and health which affects the plant growth and leads to decrease in crop production. Plant growth promoting rhizobacteria (PGPR) are beneficial bacteria which can protect the plants against many abiotic stresses, and enhance the growth. The study aimed to identify important rhizobacterial strains by using the 1-aminocyclopropane-1-carboxylate (ACC) enrichment technique and examine their inoculation effects in the growth promotion of maize, under Pb pollution. A pot experiment was conducted and six rhizobacterial isolates were used. Pb was added to 2 kg soil in each pot (with 4 seeds/pot) using Pb(NO3)2 at the rate of 0, 100, 200, 300, and 400 mg kg(-1) Pb with three replications in completely randomized design. Rhizobacterial isolates performed significantly better under all Pb levels, i.e., 100 to 400 Pb mg kg(-1) soil, compared to control. Comparing the efficacy of the rhizobacterial isolates under different Pb levels, rhizobacterial isolates having both ACC-deaminase and nitrogen-fixing activities (AN8 and AN12) showed highest increase in terms of the physical, chemical and enzymatic growth parameters of maize, followed by the rhizobacterial isolates having ACC-deaminase activity only (ACC5 and ACC8), and then the nitrogen-fixing rhizobia (Azotobacter and RN5). However, the AN8 isolate showed maximum efficiency, and highest shoot and root length (14.2 and 6.1 cm), seedling fresh and dry weights (1.91 and 0.14 g), chlorophyll a, b, and carotenoids (24.1, 30.2 and 77.7 μg/l), protein (0.82 mg/g), proline (3.42 μmol/g), glutathione S-transferase, peroxidase and catalase (12.3, 4.2 and 7.2 units/mg protein), while the lowest Pb uptake in the shoot and root (0.83 and 0.48 mg/kg) were observed under this rhizobial isolate at the highest Pb level (i.e., 400 Pb mg kg(-1) soil). The results revealed that PGPR significantly decreases the deleterious effects of Pb pollution and increases the maize growth under all Pb concentrations, i.e., 100-400 Pb mg kg(-1) soil. PGPR chelate the Pb in the soil, and ultimately influence its bioavailability, release and uptake. The PGPR having both ACC-deaminase and nitrogen-fixing abilities are more effective and resistive against Pb pollution than PGPR having either ACC-deaminase or nitrogen-fixing activity alone. The ACC enrichment technique is an efficient approach to select promising PGPR.

Null mutation of the MdACS3 gene, coding for a ripening-specific 1-aminocyclopropane-1-carboxylate synthase, leads to long shelf life in apple fruit.

PubMed

Wang, Aide; Yamakake, Junko; Kudo, Hisayuki; Wakasa, Yuhya; Hatsuyama, Yoshimichi; Igarashi, Megumi; Kasai, Atsushi; Li, Tianzhong; Harada, Takeo

2009-09-01

Expression of MdACS1, coding for 1-aminocyclopropane-1-carboxylate synthase (ACS), parallels the level of ethylene production in ripening apple (Malus domestica) fruit. Here we show that expression of another ripening-specific ACS gene (MdACS3) precedes the initiation of MdACS1 expression by approximately 3 weeks; MdACS3 expression then gradually decreases as MdACS1 expression increases. Because MdACS3 expression continues in ripening fruit treated with 1-methylcyclopropene, its transcription appears to be regulated by a negative feedback mechanism. Three genes in the MdACS3 family (a, b, and c) were isolated from a genomic library, but two of them (MdACS3b and MdACS3c) possess a 333-bp transposon-like insertion in their 5' flanking region that may prevent transcription of these genes during ripening. A single nucleotide polymorphism in the coding region of MdACS3a results in an amino acid substitution (glycine-289 --> valine) in the active site that inactivates the enzyme. Furthermore, another null allele of MdACS3a, Mdacs3a, showing no ability to be transcribed, was found by DNA sequencing. Apple cultivars homozygous or heterozygous for both null allelotypes showed no or very low expression of ripening-related genes and maintained fruit firmness. These results suggest that MdACS3a plays a crucial role in regulation of fruit ripening in apple, and is a possible determinant of ethylene production and shelf life in apple fruit.

Transcriptional Profiling of Sorghum Induced by Methyl Jasmonate, Salicylic Acid, and Aminocyclopropane Carboxylic Acid Reveals Cooperative Regulation and Novel Gene Responses1[w

PubMed Central

Salzman, Ron A.; Brady, Jeff A.; Finlayson, Scott A.; Buchanan, Christina D.; Summer, Elizabeth J.; Sun, Feng; Klein, Patricia E.; Klein, Robert R.; Pratt, Lee H.; Cordonnier-Pratt, Marie-Michèle; Mullet, John E.

2005-01-01

We have conducted a large-scale study of gene expression in the C4 monocot sorghum (Sorghum bicolor) L. Moench cv BTx623 in response to the signaling compounds salicylic acid (SA), methyl jasmonate (MeJA), and the ethylene precursor aminocyclopropane carboxylic acid. Expression profiles were generated from seedling root and shoot tissue at 3 and 27 h, using a microarray containing 12,982 nonredundant elements. Data from 102 slides and quantitative reverse transcription-PCR data on mRNA abundance from 171 genes were collected and analyzed and are here made publicly available. Numerous gene clusters were identified in which expression was correlated with particular signaling compound and tissue combinations. Many genes previously implicated in defense responded to the treatments, including numerous pathogenesis-related genes and most members of the phenylpropanoid pathway, and several other genes that may represent novel activities or pathways. Genes of the octadecanoic acid pathway of jasmonic acid (JA) synthesis were induced by SA as well as by MeJA. The resulting hypothesis that increased SA could lead to increased endogenous JA production was confirmed by measurement of JA content. Comparison of responses to SA, MeJA, and combined SA+MeJA revealed patterns of one-way and mutual antagonisms, as well as synergistic effects on regulation of some genes. These experiments thus help further define the transcriptional results of cross talk between the SA and JA pathways and suggest that a subset of genes coregulated by SA and JA may comprise a uniquely evolved sector of plant signaling responsive cascades. PMID:15863699

Upregulation of Phosphatidylinositol 3-Kinase (PI3K) Enhances Ethylene Biosynthesis and Accelerates Flower Senescence in Transgenic Nicotiana tabacum L.

PubMed

Dek, Mohd Sabri Pak; Padmanabhan, Priya; Sherif, Sherif; Subramanian, Jayasankar; Paliyath, And Gopinadhan

2017-07-15

Phosphatidylinositol 3-kinase (PI3K) is a key enzyme that phosphorylates phosphatidylinositol at 3'-hydroxyl position of the inositol head group initiating the generation of several phosphorylated phosphatidylinositols, collectively referred to as phosphoinositides. The function of PI3K in plant senescence and ethylene signal transduction process was studied by expression of Solanum lycopersicum PI3K in transgenic Nicotiana tabacum , and delineating its effect on flower senescence. Detached flowers of transgenic tobacco plants with overexpressed Sl - PI3K (OX) displayed accelerated senescence and reduced longevity, when compared to the flowers of wild type plants. Flowers from PI3K-overexpressing plants showed enhanced ethylene production and upregulated expression of 1-aminocyclopropane-1-carboxylic acid oxidase 1 ( ACO1 ). Real time polymerase chain reaction (PCR) analysis showed that PI3K was expressed at a higher level in OX flowers than in the control. Seedlings of OX-lines also demonstrated a triple response phenotype with characteristic exaggerated apical hook, shorter hypocotyls and increased sensitivity to 1-aminocyclopropane-1-carboxylate than the control wild type seedlings. In floral tissue from OX-lines, Solanum lycopersicum phosphatidylinositol 3-kinase green fluorescent protein (PI3K-GFP) chimera protein was localized primarily in stomata, potentially in cytoplasm and membrane adjacent to stomatal pores in the guard cells. Immunoblot analysis of PI3K expression in OX lines demonstrated increased protein level compared to the control. Results of the present study suggest that PI3K plays a crucial role in senescence by enhancing ethylene biosynthesis and signaling.

Comparative Indole-3-Acetic Acid Levels in the Slender Pea and Other Pea Phenotypes 1

PubMed Central

Law, David M.; Davies, Peter J.

1990-01-01

Free indole-3-acetic acid levels were measured by gas chromatography-mass spectrometry in three ultra-tall `slender' Pisum sativum L. lines differing in gibberellin content. Measurements were made for apices and stem elongation zones of light-grown plants and values were compared with wild-type, dwarf, and nana phenotypes in which internode length is genetically regulated, purportedly via the gibberellin level. Indole-3-acetic acid levels of growing stems paralleled growth rates in all lines, and were high in all three slender genotypes. Growth was inhibited by p-chlorophenoxyisobutyric acid, demonstrating the requirement of auxin activity for stem elongation, and also by the ethylene precursor 1-aminocyclopropane-1-carboxylic acid. It is concluded that the slender phenotype may arise from constant activation of a gibberellin receptor or transduction chain event leading directly or indirectly to elevated levels of indole-3-acetic acid, and that increased indole-3-acetic acid levels are a significant factor in the promotion of stem elongation. PMID:16667653

Characterisation of ethylene pathway components in non-climacteric capsicum.

PubMed

Aizat, Wan M; Able, Jason A; Stangoulis, James C R; Able, Amanda J

2013-11-28

Climacteric fruit exhibit high ethylene and respiration levels during ripening but these levels are limited in non-climacteric fruit. Even though capsicum is in the same family as the well-characterised climacteric tomato (Solanaceae), it is non-climacteric and does not ripen normally in response to ethylene or if harvested when mature green. However, ripening progresses normally in capsicum fruit when they are harvested during or after what is called the 'Breaker stage'. Whether ethylene, and components of the ethylene pathway such as 1-aminocyclopropane 1-carboxylate (ACC) oxidase (ACO), ACC synthase (ACS) and the ethylene receptor (ETR), contribute to non-climacteric ripening in capsicum has not been studied in detail. To elucidate the behaviour of ethylene pathway components in capsicum during ripening, further analysis is therefore needed. The effects of ethylene or inhibitors of ethylene perception, such as 1-methylcyclopropene, on capsicum fruit ripening and the ethylene pathway components may also shed some light on the role of ethylene in non-climacteric ripening. The expression of several isoforms of ACO, ACS and ETR were limited during capsicum ripening except one ACO isoform (CaACO4). ACS activity and ACC content were also low in capsicum despite the increase in ACO activity during the onset of ripening. Ethylene did not stimulate capsicum ripening but 1-methylcyclopropene treatment delayed the ripening of Breaker-harvested fruit. Some of the ACO, ACS and ETR isoforms were also differentially expressed upon treatment with ethylene or 1-methylcyclopropene. ACS activity may be the rate limiting step in the ethylene pathway of capsicum which restricts ACC content. The differential expression of several ethylene pathway components during ripening and upon ethylene or 1-methylclopropene treatment suggests that the ethylene pathway may be regulated differently in non-climacteric capsicum compared to the climacteric tomato. Ethylene independent pathways may also exist in non-climacteric ripening as evidenced by the up-regulation of CaACO4 during ripening onset despite being negatively regulated by ethylene exposure. However, some level of ethylene perception may still be needed to induce ripening especially during the Breaker stage. A model of capsicum ripening is also presented to illustrate the probable role of ethylene in this non-climacteric fruit.

A new insight to adsorption and accumulation of high lead concentration by exopolymer and whole cells of lead-resistant bacterium Acinetobacter junii L. Pb1 isolated from coal mine dump.

PubMed

Kushwaha, Anamika; Rani, Radha; Kumar, Sanjay; Thomas, Tarence; David, Arun Alfred; Ahmed, Meraz

2017-04-01

A lead-resistant bacterial strain was isolated from coal mine dump and identified as Acinetobacter junii Pb1 on basis of 16S rRNA (ribosomal ribonucleic acid) gene sequencing. The minimum inhibitory concentration of lead for the strain was 16,000 mg l -1 and it showed antibiotic and multi metal resistance. In aqueous culture, at an initial lead (Pb(II)) concentration of 100 and 500 mg l -1 , lead adsorption and accumulation by the isolate was 100 and 60%, at pH 7 at 30 °C after 48 and 120 h, respectively. The two fractions of exopolysaccharide (EPS), loosely associated EPS (laEPS) and bound EPS (bEPS), and whole cells (devoid of EPS) showed high binding affinity towards Pb(II). The binding affinity of laEPS towards Pb(II) (1071 mg Pb g -1 ) was three times higher than that of bEPS (321.5 mg Pb g -1 ) and 6.5 times higher than that of whole cells (165 mg Pb g -1 ). The binding affinity of EPS and whole cells with Pb(II), reported in the current study, is considerably higher as compared to that reported in the literature, till date. SEM analysis, showed an increase in thickness of cells on exposure to Pb(II) and TEM analysis, revealed its accumulation (interior of cell) and its adsorption (with the external cell surface). The isolate was also found to be positive for indole acetic acid (IAA) and 1-aminocyclopropane-1-carboxylate (ACC) deaminase production which helps in promoting plant growth. Thus, this study provides a new understanding towards Pb(II) uptake by A. junii Pb1, highlighting its potential on the restoration of Pb(II) contaminated repositories.

Comparison of the role of gibberellins and ethylene in response to submergence of two lowland rice cultivars, Senia and Bomba.

PubMed

Dubois, Vincent; Moritz, Thomas; García-Martínez, José L

2011-02-15

We examined the gibberellin (GA) and ethylene regulation of submergence-induced elongation in seedlings of the submergence-tolerant lowland rice (Oryza sativa L.) cvs Senia and Bomba. Elongation was enhanced after germination to facilitate water escape and reach air. We found that submergence-induced elongation depends on GA because it was counteracted by paclobutrazol (an inhibitor of GA biosynthesis), an effect that was negated by GA(3). Moreover, in the cv Senia, submergence increased the content of active GA(1) and its immediate precursors (GA(53), GA(19) and GA(20)) by enhancing expression of several GA biosynthesis genes (OsGA20ox1 and -2, and OsGA3ox2), but not by decreasing expression of several OsGA2ox (GA inactivating genes). Senia seedlings, in contrast to Bomba seedlings, did not elongate in response to ethylene or 1-aminocyclopropane-1-carboxylic-acid (ACC; an ethylene precursor) application, and submergence-induced elongation was not reduced in the presence of 1-methylcyclopropene (1-MCP; an ethylene perception inhibitor). Ethylene emanation was similar in Senia seedlings grown in air and in submerged-grown seedlings following de-submergence, while it increased in Bomba. The expression of ethylene biosynthesis genes (OsACS1, -2 and -3, and OsACO1) was not affected in Senia, but expression of OsACS5 was rapidly enhanced in Bomba upon submergence. Our results support the conclusion that submergence elongation enhancement of lowland rice is due to alteration of GA metabolism leading to an increase in active GA (GA(1)) content. Interestingly, in the cv Senia, in contrast to cv Bomba, this was triggered through an ethylene-independent mechanism. Copyright © 2010 Elsevier GmbH. All rights reserved.

5′-Methylthioadenosine Nucleosidase and 5-Methylthioribose Kinase Activities and Ethylene Production during Tomato Fruit Development and Ripening 1

PubMed Central

Kushad, Mosbah M.; Richardson, Daryl G.; Ferro, Adolph J.

1985-01-01

5′-Methylthioadenosine (MTA) nucleosidase and 5-methylthioribose (MTR) kinase activities were measured in crude extracts of tomato fruits (Lycopersicon esculentum Mill cv Rutgers) during fruit development and ripening. The highest activity of MTA nucleosidase (1.2 nanomoles per milligram protein per minute) was observed in small green fruits. The activity decreased during ripening; at the overripe stage only 6.5% of the peak activity remained. MTR kinase activity was low at the small green stage and increased thereafter until it reached peak activity at the breaker stage (0.7 nanomoles per milligram protein per minute) followed by a sharp decline at the later stages of fruit ripening. 1-Amino-cyclopropane-1-carboxylic acid (ACC) levels peaked at the red stage, while ethylene reached its highest level at the light-red stage. Several analogs of MTA and MTR were tested as both enzyme and ethylene inhibitors. Of the MTA analogs examined for their ability to inhibit MTA nucleosidase, 5′-chloroformycin reduced enzyme activity 89%, whereas 5′-chloroadenosine, 5′-isobutylthioadenosine, 5′-isopropylthioadenosine, and 5′-ethylthioadenosine inhibited the reaction with MTA by about 40%. 5′-Chloroformycin and 5′-chloroadenosine inhibited ethylene production over a period of 24 hours by about 64 and 42%, respectively. Other analogs of MTA were not effective inhibitors of ethylene production, whereas aminoethoxyvinylglycine showed a 34% inhibition over the same period of time. Of the MTR analogs tested, 5-isobutylthioribose was the most effective inhibitor of both MTR-kinase (41%) and ethylene production (35%). PMID:16664444

Null Mutation of the MdACS3 Gene, Coding for a Ripening-Specific 1-Aminocyclopropane-1-Carboxylate Synthase, Leads to Long Shelf Life in Apple Fruit1[W][OA

PubMed Central

Wang, Aide; Yamakake, Junko; Kudo, Hisayuki; Wakasa, Yuhya; Hatsuyama, Yoshimichi; Igarashi, Megumi; Kasai, Atsushi; Li, Tianzhong; Harada, Takeo

2009-01-01

Expression of MdACS1, coding for 1-aminocyclopropane-1-carboxylate synthase (ACS), parallels the level of ethylene production in ripening apple (Malus domestica) fruit. Here we show that expression of another ripening-specific ACS gene (MdACS3) precedes the initiation of MdACS1 expression by approximately 3 weeks; MdACS3 expression then gradually decreases as MdACS1 expression increases. Because MdACS3 expression continues in ripening fruit treated with 1-methylcyclopropene, its transcription appears to be regulated by a negative feedback mechanism. Three genes in the MdACS3 family (a, b, and c) were isolated from a genomic library, but two of them (MdACS3b and MdACS3c) possess a 333-bp transposon-like insertion in their 5′ flanking region that may prevent transcription of these genes during ripening. A single nucleotide polymorphism in the coding region of MdACS3a results in an amino acid substitution (glycine-289 → valine) in the active site that inactivates the enzyme. Furthermore, another null allele of MdACS3a, Mdacs3a, showing no ability to be transcribed, was found by DNA sequencing. Apple cultivars homozygous or heterozygous for both null allelotypes showed no or very low expression of ripening-related genes and maintained fruit firmness. These results suggest that MdACS3a plays a crucial role in regulation of fruit ripening in apple, and is a possible determinant of ethylene production and shelf life in apple fruit. PMID:19587104

The ACC deaminase expressing endophyte Pseudomonas spp. Enhances NaCl stress tolerance by reducing stress-related ethylene production, resulting in improved growth, photosynthetic performance, and ionic balance in tomato plants.

PubMed

Win, Khin Thuzar; Fukuyo, Tanaka; Keiki, Okazaki; Ohwaki, Yoshinari

2018-06-01

Plant growth promoting bacteria (PGPB) endophytes that express 1-aminocyclopropane-1-carboxylate (ACC) deaminase reportedly confer plant tolerance to abiotic stresses such as salinity by lowering stress-related ethylene levels. Two preselected ACC deaminase expressing endophytic Pseudomonas spp. strains, OFT2 and OFT5, were compared in terms of their potential to promote plant growth, leaf water contents, photosynthetic performance, and ionic balance of tomato plants under conditions of moderate NaCl stress (75 mM). Salinity stress strongly affected growth, leaf water contents, and photosynthetic performance of tomato seedlings, and inoculation with either OFT2 or OFT5 ameliorated these adverse effects. Decreases in plant biomass due to salinity stress were significant in both uninoculated control plants and in plants inoculated with OFT2 compared with plants without NaCl stress. However, no reductions in total biomass were observed in plants that were inoculated with the OFT5 strain. Strain OFT5 influenced growth, physiological status, and ionic balance of tomato plants more efficiently than strain OFT2 under NaCl stress. In particular, inoculated OFT5 reduced salt-induced ethylene production by tomato seedlings, and although it did not reduce shoot uptake of Na, it promoted shoot uptake of other macronutrients (P, K, and Mg) and micronutrients (Mn, Fe, Cu, and Zn). These nutrients may activate processes that alleviate the effects of salt, suggesting that OFT5 can be used to improve nutrient uptake and plant growth under moderate salt-affected conditions by reducing stress-related ethylene levels. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Increased growth and root Cu accumulation of Sorghum sudanense by endophytic Enterobacter sp. K3-2: Implications for Sorghum sudanense biomass production and phytostabilization.

PubMed

Li, Ya; Wang, Qi; Wang, Lu; He, Lin-Yan; Sheng, Xia-Fang

2016-02-01

Endophytic bacterial strain K3-2 was isolated from the roots of Sorghum sudanense (an bioenergy plant) grown in a Cu mine wasteland soils and characterized. Strain K3-2 was identified as Enterobacter sp. based on 16S rRNA gene sequence analysis. Strain K3-2 exhibited Cu resistance and produced 1-aminocyclopropane-1-carboxylate (ACC) deaminase, indole-3-acetic acid (IAA), siderophores, and arginine decarboxylase. Pot experiments showed that strain K3-2 significantly increased the dry weight and root Cu accumulation of Sorghum sudanense grown in the Cu mine wasteland soils. Furthermore, increase in total Cu uptake (ranging from 49% to 95%) of the bacterial inoculated-Sorghum sudanense was observed compared to the control. Notably, most of Cu (83-86%) was accumulated in the roots of Sorghum sudanense. Furthermore, inoculation with strain K3-2 was found to significantly increase Cu bioconcentration factors and the proportions of IAA- and siderophore-producing bacteria in the root interiors and rhizosphere soils of Sorghum sudanense compared with the control. Significant decrease in the available Cu content was also observed in the rhizosphere soils of the bacterial-inoculated Sorghum sudanense. The results suggest that the endophytic bacterial strain K3-2 may be exploited for promoting Sorghum sudanense biomass production and Cu phytostabilization in the Cu mining wasteland soils. Copyright © 2015 Elsevier Inc. All rights reserved.

A Factor Linking Floral Organ Identity and Growth Revealed by Characterization of the Tomato Mutant unfinished flower development (ufd).

PubMed

Poyatos-Pertíñez, Sandra; Quinet, Muriel; Ortíz-Atienza, Ana; Yuste-Lisbona, Fernando J; Pons, Clara; Giménez, Estela; Angosto, Trinidad; Granell, Antonio; Capel, Juan; Lozano, Rafael

2016-01-01

Floral organogenesis requires coordinated interactions between genes specifying floral organ identity and those regulating growth and size of developing floral organs. With the aim to isolate regulatory genes linking both developmental processes (i.e., floral organ identity and growth) in the tomato model species, a novel mutant altered in the formation of floral organs was further characterized. Under normal growth conditions, floral organ primordia of mutant plants were correctly initiated, however, they were unable to complete their development impeding the formation of mature and fertile flowers. Thus, the growth of floral buds was blocked at an early stage of development; therefore, we named this mutant as unfinished flower development ( ufd ). Genetic analysis performed in a segregating population of 543 plants showed that the abnormal phenotype was controlled by a single recessive mutation. Global gene expression analysis confirmed that several MADS-box genes regulating floral identity as well as other genes participating in cell division and different hormonal pathways were affected in their expression patterns in ufd mutant plants. Moreover, ufd mutant inflorescences showed higher hormone contents, particularly ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) and strigol compared to wild type. Such results indicate that UFD may have a key function as positive regulator of the development of floral primordia once they have been initiated in the four floral whorls. This function should be performed by affecting the expression of floral organ identity and growth genes, together with hormonal signaling pathways.

Heat stress differentially modifies ethylene biosynthesis and signaling in pea floral and fruit tissues.

PubMed

Savada, Raghavendra P; Ozga, Jocelyn A; Jayasinghege, Charitha P A; Waduthanthri, Kosala D; Reinecke, Dennis M

2017-10-01

Ethylene biosynthesis is regulated in reproductive tissues in response to heat stress in a manner to optimize resource allocation to pollinated fruits with developing seeds. High temperatures during reproductive development are particularly detrimental to crop fruit/seed production. Ethylene plays vital roles in plant development and abiotic stress responses; however, little is known about ethylene's role in reproductive tissues during development under heat stress. We assessed ethylene biosynthesis and signaling regulation within the reproductive and associated tissues of pea during the developmental phase that sets the stage for fruit-set and seed development under normal and heat-stress conditions. The transcript abundance profiles of PsACS [encode enzymes that convert S-adenosyl-L-methionine to 1-aminocyclopropane-1-carboxylic acid (ACC)] and PsACO (encode enzymes that convert ACC to ethylene), and ethylene evolution were developmentally, environmentally, and tissue-specifically regulated in the floral/fruit/pedicel tissues of pea. Higher transcript abundance of PsACS and PsACO in the ovaries, and PsACO in the pedicels was correlated with higher ethylene evolution and ovary senescence and pedicel abscission in fruits that were not pollinated under control temperature conditions. Under heat-stress conditions, up-regulation of ethylene biosynthesis gene expression in pre-pollinated ovaries was also associated with higher ethylene evolution and lower retention of these fruits. Following successful pollination and ovule fertilization, heat-stress modified PsACS and PsACO transcript profiles in a manner that suppressed ovary ethylene evolution. The normal ethylene burst in the stigma/style and petals following pollination was also suppressed by heat-stress. Transcript abundance profiles of ethylene receptor and signaling-related genes acted as qualitative markers of tissue ethylene signaling events. These data support the hypothesis that ethylene biosynthesis is regulated in reproductive tissues in response to heat stress to modulate resource allocation dynamics.

Novel functions of the Arabidopsis transcription factor TCP5 in petal development and ethylene biosynthesis.

PubMed

van Es, Sam W; Silveira, Sylvia R; Rocha, Diego I; Bimbo, Andrea; Martinelli, Adriana P; Dornelas, Marcelo C; Angenent, Gerco C; Immink, Richard G H

2018-06-01

The flowers of most dicotyledons have petals that, together with the sepals, initially protect the reproductive organs. Later during development petals are required to open the flower and to attract pollinators. This diverse set of functions demands tight temporal and spatial regulation of petal development. We studied the functioning of the Arabidopsis thaliana TCP5-like transcription factors (TFs) in petals. Overexpression of TCP5 in petal epidermal cells results in smaller petals, whereas tcp5 tcp13 tcp17 triple knockout lines have wider petals with an increased surface area. Comprehensive expression studies revealed effects of TCP5-like TFs on the expression of genes related to the cell cycle, growth regulation and organ growth. Additionally, the ethylene biosynthesis genes 1-amino-cyclopropane-1-carboxylate (ACC) synthase 2 (ACS2) and ACC oxidase 2 (ACO2) and several ETHYLENE RESPONSE FACTORS (ERFs) are found to be differentially expressed in TCP5 mutant and overexpression lines. Chromatin immunoprecipitation-quantitative PCR showed direct binding of TCP5 to the ACS2 locus in vivo. Ethylene is known to influence cell elongation, and the petal phenotype of the tcp5 tcp13 tcp17 mutant could be complemented by treatment of the plants with an ethylene pathway inhibitor. Taken together, this reveals a novel role for TCP5-like TFs in the regulation of ethylene-mediated petal development and growth. © 2018 The Authors The Plant Journal published by John Wiley & Sons Ltd and Society for Experimental Biology.

Silencing of the ACC synthase gene ACACS2 causes delayed flowering in pineapple [Ananas comosus (L.) Merr.].

PubMed

Trusov, Yuri; Botella, José Ramón

2006-01-01

Flowering is a crucial developmental stage in the plant life cycle. A number of different factors, from environmental to chemical, can trigger flowering. In pineapple, and other bromeliads, it has been proposed that flowering is triggered by a small burst of ethylene production in the meristem in response to environmental cues. A 1-amino-cyclopropane-1-carboxylate synthase (ACC synthase) gene has been cloned from pineapple (ACACS2), which is induced in the meristem under the same environmental conditions that induce flowering. Two transgenic pineapple lines have been produced containing co-suppression constructs designed to down-regulate the expression of the ACACS2 gene. Northern analysis revealed that the ACACS2 gene was silenced in a number of transgenic plants in both lines. Southern hybridization revealed clear differences in the methylation status of silenced versus non-silenced plants by the inability of a methylation-sensitive enzyme to digest within the ACACS2 DNA extracted from silenced plants, indicating that methylation is the cause of the observed co-suppression of the ACACS2 gene. Flowering characteristics of the transgenic plants were studied under field conditions in South East Queensland, Australia. Flowering dynamics studies revealed significant differences in flowering behaviour, with transgenic plants exhibiting silencing showing a marked delay in flowering when compared with non-silenced transgenic plants and control non-transformed plants. It is argued that the ACACS2 gene is one of the key contributors towards triggering 'natural flowering' in mature pineapples under commercial field conditions.

Hormonal and Nutritional Features in Contrasting Rootstock-mediated Tomato Growth under Low-phosphorus Nutrition.

PubMed

Martínez-Andújar, Cristina; Ruiz-Lozano, Juan M; Dodd, Ian C; Albacete, Alfonso; Pérez-Alfocea, Francisco

2017-01-01

Grafting provides a tool aimed to increase low-P stress tolerance of crops, however, little is known about the mechanism (s) by which rootstocks can confer resistance to P deprivation. In this study, 4 contrasting groups of rootstocks from different genetic backgrounds ( Solanum lycopersicum var. cerasiforme and introgression and recombinant inbred lines derived from the wild relatives S. pennellii and S. pimpinellifolium ) were grafted to a commercial F1 hybrid scion and cultivated under control (1 mM, c ) and P deficient (0.1 mM, p ) conditions for 30 days, to analyze rootstocks-mediated traits that impart low ( L , low shoot dry weight, SDW) or high ( H , high SDW) vigor. Xylem sap ionic and hormonal anlyses leaf nutritional status suggested that some physiological traits can explain rootstocks impacts on shoot growth. Although xylem P concentration increased with root biomass under both growing conditions, shoot biomass under low-P was explained by neither changes in root growth nor P transport and assimilation. Indeed, decreased root P export only explained the sensitivity of the HcLp rootstocks, while leaf P status was similarly affected in all graft combinations. Interestingly, most of the nutrients analyzed in the xylem sap correlated with root biomass under standard fertilization but only Ca was consistently related to shoot biomass under both control and low-P, suggesting an important role for this nutrient in rootstock-mediated vigor. Moreover, foliar Ca, S, and Mn concentrations were (i) specifically correlated with shoot growth under low-P and (ii) positively and negatively associated to the root-to-shoot transport of the cytokinin trans -zeatin ( t -Z) and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), respectively. Indeed, those hormones seem to play an antagonistic positive ( t -Z) and negative (ACC) role in the rootstock-mediated regulation of shoot growth in response to P nutrition. The use of Hp -type rootstocks seems to enhance P use efficiency of a commercial scion variety, therefore could potentially be used for increasing yield and agronomic stability under low P availability.

Arsenic-tolerant plant-growth-promoting bacteria isolated from arsenic-polluted soils in South Korea.

PubMed

Shagol, Charlotte C; Krishnamoorthy, Ramasamy; Kim, Kiyoon; Sundaram, Subbiah; Sa, Tongmin

2014-01-01

The Janghang smelter in Chungnam, South Korea started in 1936 was subsequently shutdown in 1989 due to heavy metal (loid) pollution concerns in the vicinity. Thus, there is a need for the soil in the area to be remediated to make it usable again especially for agricultural purposes. The present study was conducted to exploit the potential of arsenic (As)-tolerant bacteria thriving in the vicinity of the smelter-polluted soils to enhance phytoremediation of hazardous As. We studied the genetic and taxonomic diversity of 21 As-tolerant bacteria isolated from soils nearer to and away from the smelter. These isolates belonging to the genera Brevibacterium, Pseudomonas, Microbacterium, Rhodococcus, Rahnella, and Paenibacillus, could tolerate high concentrations of arsenite (As(III)) and arsenate (As(V)) with the minimum inhibitory concentration ranging from 3 to >20 mM for NaAsO2 and 140 to 310 mM NaH2AsO4 · 7H2O, respectively. All isolates exhibited As(V) reduction except Pseudomonas koreensis JS123, which exhibited both oxidation and reduction of As. Moreover, all the 21 isolates produced indole acetic acid (IAA), 13 isolates exhibited 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, 12 produced siderophore, 17 solubilized phosphate, and 13 were putative nitrogen fixers under in vitro conditions. Particularly, Rhodococcus aetherivorans JS2210, P. koreensis JS2214, and Pseudomonas sp. JS238 consistently increased root length of maize in the presence of 100 and 200 μM As(V). Possible utilization of these As-tolerant plant-growth-promoting bacteria can be a potential strategy in increasing the efficiency of phytoremediation in As-polluted soils.

Assessing the allelotypic effect of two aminocyclopropane carboxylic acid synthase-encoding genes MdACS1 and MdACS3a on fruit ethylene production and softening in Malus

PubMed Central

Dougherty, Laura; Zhu, Yuandi; Xu, Kenong

2016-01-01

Phytohormone ethylene largely determines apple fruit shelf life and storability. Previous studies demonstrated that MdACS1 and MdACS3a, which encode 1-aminocyclopropane-1-carboxylic acid synthases (ACS), are crucial in apple fruit ethylene production. MdACS1 is well-known to be intimately involved in the climacteric ethylene burst in fruit ripening, while MdACS3a has been regarded a main regulator for ethylene production transition from system 1 (during fruit development) to system 2 (during fruit ripening). However, MdACS3a was also shown to have limited roles in initiating the ripening process lately. To better assess their roles, fruit ethylene production and softening were evaluated at five time points during a 20-day post-harvest period in 97 Malus accessions and in 34 progeny from 2 controlled crosses. Allelotyping was accomplished using an existing marker (ACS1) for MdACS1 and two markers (CAPS866 and CAPS870) developed here to specifically detect the two null alleles (ACS3a-G289V and Mdacs3a) of MdACS3a. In total, 952 Malus accessions were allelotyped with the three markers. The major findings included: The effect of MdACS1 was significant on fruit ethylene production and softening while that of MdACS3a was less detectable; allele MdACS1–2 was significantly associated with low ethylene and slow softening; under the same background of the MdACS1 allelotypes, null allele Mdacs3a (not ACS3a-G289V) could confer a significant delay of ethylene peak; alleles MdACS1–2 and Mdacs3a (excluding ACS3a-G289V) were highly enriched in M. domestica and M. hybrid when compared with those in M. sieversii. These findings are of practical implications in developing apples of low and delayed ethylene profiles by utilizing the beneficial alleles MdACS1-2 and Mdacs3a. PMID:27231553

Hormonal and metabolic regulation of tomato fruit sink activity and yield under salinity

PubMed Central

Albacete, Alfonso; Cantero-Navarro, Elena; Balibrea, María E.; Großkinsky, Dominik K.; de la Cruz González, María; Martínez-Andújar, Cristina; Smigocki, Ann C.; Roitsch, Thomas; Pérez-Alfocea, Francisco

2014-01-01

Salinization of water and soil has a negative impact on tomato (Solanum lycopersicum L.) productivity by reducing growth of sink organs and by inducing senescence in source leaves. It has been hypothesized that yield stability implies the maintenance or increase of sink activity in the reproductive structures, thus contributing to the transport of assimilates from the source leaves through changes in sucrolytic enzymes and their regulation by phytohormones. In this study, classical and functional physiological approaches have been integrated to study the influence of metabolic and hormonal factors on tomato fruit sink activity, growth, and yield: (i) exogenous hormones were applied to plants, and (ii) transgenic plants overexpressing the cell wall invertase (cwInv) gene CIN1 in the fruits and de novo cytokinin (CK) biosynthesis gene IPT in the roots were constructed. Although salinity reduces fruit growth, sink activity, and trans-zeatin (tZ) concentrations, it increases the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) during the actively growing period (25 days after anthesis). Indeed, exogenous application of the CK analogue kinetin to salinized actively growing fruits recovered sucrolytic activities (mainly cwInv and sucrose synthase), sink strength, and fruit weight, whereas the ethylene-releasing compound ethephon had a negative effect in equivalent non-stressed fruits. Fruit yield was increased by both the constitutive expression of CIN1 in the fruits (up to 4-fold) or IPT in the root (up to 30%), owing to an increase in the fruit number (lower flower abortion) and in fruit weight. This is possibly related to a recovery of sink activity in reproductive tissues due to both (i) increase in sucrolytic activities (cwInv, sucrose synthase, and vacuolar and cytoplasmic invertases) and tZ concentration, and (ii) a decrease in the ACC levels and the activity of the invertase inhibitor. This study provides new functional evidences about the role of metabolic and hormonal inter-regulation of local sink processes in controlling tomato fruit sink activity, growth, and yield under salinity. PMID:25170099

The Effect of Ethylene and Propylene Pulses on Respiration, Ripening Advancement, Ethylene-Forming Enzyme, and 1-Aminocyclopropane-1-carboxylic Acid Synthase Activity in Avocado Fruit 12

PubMed Central

Starrett, David A.; Laties, George G.

1991-01-01

When early-season avocado fruit (Persea americana Mill. cv Hass) were treated with ethylene or propylene for 24 hours immediately on picking, the time to the onset of the respiratory climacteric, i.e. the lag period, remained unchanged compared with that in untreated fruit. When fruit were pulsed 24 hours after picking, on the other hand, the lag period was shortened. In both cases, however, a 24 hour ethylene or propylene pulse induced a transient increase in respiration, called the pulse-peak, unaccompanied by ethylene production (IL Eaks [1980] Am Soc Hortic Sci 105: 744-747). The pulse also caused a sharp rise in ethylene-forming enzyme activity in both cases, without any increase in the low level of 1-aminocyclopropane-1-carboxylic acid synthase activity. Thus, the shortening of the lag period by an ethylene pulse is not due to an effect of ethylene on either of the two key enzymes in ethylene biosynthesis. A comparison of two-dimensional polyacrylamide gel electrophoresis polypeptide profiles of in vitro translation products of poly(A+) mRNA from control and ethylene-pulsed fruit showed both up- and down-regulation in response to ethylene pulsing of a number of genes expressed during the ripening syndrome. It is proposed that the pulse-peak or its underlying events reflect an intrinsic element in the ripening process that in late-season or continuously ethylene-treated fruit may be subsumed in the overall climacteric response. A computerized system that allows continuous readout of multiple samples has established that the continued presentation of exogeneous ethylene or propylene to preclimacteric fruit elicits a dual respiration response comprising the merged pulse-peak and climacteric peak in series. The sequential removal of cores from a single fruit has proven an unsatisfactory sampling procedure inasmuch as coring induces wound ethylene, evokes a positive respiration response, and advances ripening. PMID:16668073

TOFA suppresses ovarian cancer cell growth in vitro and in vivo.

PubMed

Li, Shu; Qiu, Lihua; Wu, Buchu; Shen, Haoran; Zhu, Jing; Zhou, Liang; Gu, Liying; Di, Wen

2013-08-01

A characteristic feature of cancer cells is the activation of de novo fatty acid synthesis. Acetyl‑CoA carboxylase (ACC) is a key enzyme in fatty acid synthesis, accelerating the reaction that carboxylates cytosolic acetyl‑CoA to form malonyl‑CoA. ACC is highly expressed in several types of human cancer and is important in breast and prostate cancer cell growth. The aim of the present study was to investigate the effects of 5‑tetradecyloxy‑2‑furoic acid (TOFA), an allosteric inhibitor of ACC, on the proliferation and cell cycle progression of the ovarian cancer cell lines COC1 and COC1/DDP. TOFA was found to be cytotoxic to COC1 and COC1/DDP cells with a 50% inhibitory concentration (IC50) of ~26.1 and 11.6 µg/ml, respectively. TOFA inhibited the proliferation of the cancer cells examined in a time‑ and dose‑dependent manner, arrested the cells in the G0/G1 cell cycle phase and induced apoptosis. The expression of the cell cycle regulating proteins cyclin D1 and cyclin-dependent kinase (CDK) 4, as well as the expression of the apoptosis‑related proteins caspase‑3 and Bcl‑2, were detected by western blot analysis. Cyclin D1, CDK4 and Bcl‑2 protein expression was inhibited by TOFA, while caspase‑3 was cleaved and activated. To the best of our knowledge, the present study demonstrated for the first time that TOFA inhibits COC1/DDP cell growth in ovarian tumor mouse xenografts. By inhibiting ACC, TOFA may be a promising small molecule agent for ovarian cancer therapy.

Myco-phytoremediation of arsenic- and lead-contaminated soils by Helianthus annuus and wood rot fungi, Trichoderma sp. isolated from decayed wood.

PubMed

Govarthanan, M; Mythili, R; Selvankumar, T; Kamala-Kannan, S; Kim, H

2018-04-30

In the present study, Helianthus annuus grown in arsenic- (As) and lead- (Pb) contaminated soil were treated with plant-growth promoting fungi Trichoderma sp. MG isolated from decayed wood and assessed for their phytoremediation efficiency. The isolate MG exhibited a high tolerance to As (650mg/L) and Pb (500mg/L), and could remove > 70% of metals in aqueous solution with an initial concentration of 100mg/L each. In addition, the isolate MG was screened for plant-growth-promoting factors such as siderophores, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, indole acetic acid (IAA) synthesis, and phosphate solubilisation. Phytoremediation studies indicated that treatment of H. annuus with the isolate MG had the maximum metal-accumulation in shoots (As; 67%, Pb; 59%). Furthermore, a significant increase in the soil extracellular enzyme-activities was observed in myco-phytoremediated soils. The activities of phosphatase (35 U/g dry soil), dehydrogenase (41mg TPF/g soil), cellulase (37.2mg glucose/g/2h), urease (55.4mgN/g soil/2h), amylase (49.3mg glucose/g/2h) and invertase (45.3mg glucose/g/2h) significantly increased by 12%, 14%, 12%, 22%, 19% and 14% in As contaminated soil, respectively. Similarly, the activities of phosphatase (31.4U/g dry soil), dehydrogenase (39.3mg TPF/g soil), cellulase (37.1mg glucose/g/2h), urease (49.8mgN/g soil/2h), amylase (46.3mg glucose/g/2h), and invertase (42.1mg glucose/g/2h) significantly increased by 11%, 15%, 11%, 18%, 20% and 14% in Pb contaminated soil, respectively. Obtained results indicate that the isolate MG could be a potential strain for myco-phytoremediation of As and Pb contaminated soil. Copyright © 2018 Elsevier Inc. All rights reserved.

Ethylene induced shikonin biosynthesis in shoot culture of Lithospermum erythrorhizon.

PubMed

Touno, Kaori; Tamaoka, Jin; Ohashi, Yuko; Shimomura, Koichiro

2005-02-01

Lithospermum erythrorhizon shoots, cultured on phytohormone-free Murashige and Skoog solid medium, produced shikonin derivatives, whereas shoots cultured in well-ventilated petri dishes, produced small amount. Analysis by gas chromatography revealed the presence of ethylene in non-ventilated petri dishes where the shoots, producing shikonin derivatives, were cultured. Therefore, the possible involvement of ethylene in shikonin biosynthesis of shoot cultures was investigated. Treatment of ethylene or the ethylene precursor, 1-aminocyclopropane-1-carboxylic acid, resulted in increasing shikonin derivatives contents in cultured shoots. Silver ion, an ethylene-response inhibitor, or aminoethoxyvinylglycine, an ethylene biosynthesis inhibitor, decreased production of shikonin derivatives in cultured shoots. Our results indicate that ethylene is one of the regulatory elements of shikonin biosynthesis in L. erythrorhizon shoot culture.

Enterobacter asburiae KUNi5, a Nickel Resistant Bacterium for Possible Bioremediation of Nickel Contaminated Sites.

PubMed

Paul, Anirudha; Mukherjee, Samir Kumar

2016-01-01

Nickel resistant bacterial strain Enterobacter asburiae KUNi5 was isolated and showed resistance up to 15 mM and could remove Ni optimally better at 37 degrees C and pH 7. Maximum removal was found at initial concentration of 0.5 to 2 mM, however, growth and Ni removal were affected by other heavy metals. Major amount of the metal was accumulated in the membrane fractions and certain negatively charged groups were found responsible for Ni binding. KUNi5 could also produce 1-aminocyclopropane-1-carboxylate deaminase, indole-acetic acid and siderophore. It seems that KUNi5 could be a possible candidate for Ni detoxification and plant growth promotion in Ni-contaminated field.

Characterisation of ethylene pathway components in non-climacteric capsicum

PubMed Central

2013-01-01

Background Climacteric fruit exhibit high ethylene and respiration levels during ripening but these levels are limited in non-climacteric fruit. Even though capsicum is in the same family as the well-characterised climacteric tomato (Solanaceae), it is non-climacteric and does not ripen normally in response to ethylene or if harvested when mature green. However, ripening progresses normally in capsicum fruit when they are harvested during or after what is called the ‘Breaker stage’. Whether ethylene, and components of the ethylene pathway such as 1-aminocyclopropane 1-carboxylate (ACC) oxidase (ACO), ACC synthase (ACS) and the ethylene receptor (ETR), contribute to non-climacteric ripening in capsicum has not been studied in detail. To elucidate the behaviour of ethylene pathway components in capsicum during ripening, further analysis is therefore needed. The effects of ethylene or inhibitors of ethylene perception, such as 1-methylcyclopropene, on capsicum fruit ripening and the ethylene pathway components may also shed some light on the role of ethylene in non-climacteric ripening. Results The expression of several isoforms of ACO, ACS and ETR were limited during capsicum ripening except one ACO isoform (CaACO4). ACS activity and ACC content were also low in capsicum despite the increase in ACO activity during the onset of ripening. Ethylene did not stimulate capsicum ripening but 1-methylcyclopropene treatment delayed the ripening of Breaker-harvested fruit. Some of the ACO, ACS and ETR isoforms were also differentially expressed upon treatment with ethylene or 1-methylcyclopropene. Conclusions ACS activity may be the rate limiting step in the ethylene pathway of capsicum which restricts ACC content. The differential expression of several ethylene pathway components during ripening and upon ethylene or 1-methylclopropene treatment suggests that the ethylene pathway may be regulated differently in non-climacteric capsicum compared to the climacteric tomato. Ethylene independent pathways may also exist in non-climacteric ripening as evidenced by the up-regulation of CaACO4 during ripening onset despite being negatively regulated by ethylene exposure. However, some level of ethylene perception may still be needed to induce ripening especially during the Breaker stage. A model of capsicum ripening is also presented to illustrate the probable role of ethylene in this non-climacteric fruit. PMID:24286334

Endophytic Cultivable Bacteria of the Metal Bioaccumulator Spartina maritima Improve Plant Growth but Not Metal Uptake in Polluted Marshes Soils

PubMed Central

Mesa, Jennifer; Mateos-Naranjo, Enrique; Caviedes, Miguel A.; Redondo-Gómez, Susana; Pajuelo, Eloisa; Rodríguez-Llorente, Ignacio D.

2015-01-01

Endophytic bacterial population was isolated from Spartina maritima tissues, a heavy metal bioaccumulator cordgrass growing in the estuaries of Tinto, Odiel, and Piedras River (south west Spain), one of the most polluted areas in the world. Strains were identified and ability to tolerate salt and heavy metals along with plant growth promoting and enzymatic properties were analyzed. A high proportion of these bacteria were resistant toward one or several heavy metals and metalloids including As, Cu, and Zn, the most abundant in plant tissues and soil. These strains also exhibited multiple enzymatic properties as amylase, cellulase, chitinase, protease and lipase, as well as plant growth promoting properties, including nitrogen fixation, phosphates solubilization, and production of indole-3-acetic acid (IAA), siderophores and 1-aminocyclopropane-1-carboxylate (ACC) deaminase. The best performing strains (Micrococcus yunnanensis SMJ12, Vibrio sagamiensis SMJ18, and Salinicola peritrichatus SMJ30) were selected and tested as a consortium by inoculating S. maritima wild plantlets in greenhouse conditions along with wild polluted soil. After 30 days, bacterial inoculation improved plant photosynthetic traits and favored intrinsic water use efficiency. However, far from stimulating plant metal uptake, endophytic inoculation lessened metal accumulation in above and belowground tissues. These results suggest that inoculation of S. maritima with indigenous metal-resistant endophytes could mean a useful approach in order to accelerate both adaption and growth of this indigenous cordgrass in polluted estuaries in restorative operations, but may not be suitable for rhizoaccumulation purposes. PMID:26733985

Biotoxic impact of heavy metals on growth, oxidative stress and morphological changes in root structure of wheat (Triticum aestivum L.) and stress alleviation by Pseudomonas aeruginosa strain CPSB1.

PubMed

Rizvi, Asfa; Khan, Mohd Saghir

2017-10-01

Rapid industrialization and uncontrolled metal discharge into environment is a global concern for crop production. Metal tolerant bacterium isolated from chilli rhizosphere was identified as Pseudomonas aeruginosa by 16S rDNA sequence analysis. Pseudomonas aeruginosa tolerated high concentrations of Cu (1400 μg ml -1 ), Cd (1000 μg ml -1 ) and Cr (1000 μg ml -1 ). Pseudomonas aeruginosa CPSB1 produced multiple plant growth promoting biomolecules in the presence and absence of metals. Strain CPSB1 solubilized P at 400 μg ml -1 of Cd, Cr and Cu. The strain was positive for indole-3-acetic acid (IAA), siderophores, hydrogen cyanide (HCN), ammonia (NH 3 ) and 1-aminocyclopropane-1-carboxylate (ACC) deaminase when grown with/without metals. The phytotoxic effects on wheat increased with increasing Cd, Cr and Cu rates. The P. aeruginosa CPSB1 inoculated wheat in contrast had better growth and yields under Cu, Cd and Cr stress. The root dry biomass of inoculated plants was enhanced by 44, 28 and 48% at 2007 mg Cu kg -1 , 36 mg Cd kg -1 and 204 mg Cr kg -1 , respectively. The bioinoculant enhanced number of spikes, grain and straw yields by 25, 17 and 12%, respectively. Pseudomonas aeruginosa CPSB1 significantly declined the levels of catalase (CAT), glutathione reductase (GR) and superoxide dismutase SOD), proline and malondialdehyde (MDA), and reduced metal uptake by wheat. The study demonstrated that P. aeruginosa CPSB1 possessed plant growth promoting potentials, showed metal tolerance capability and had ability to counteract deleterious metal impacts. Due to these, P. aeruginosa CPSB1 could be used as bioinoculant for enhancing wheat production even in metal contaminated soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

Transcriptional profiling reveals elevated CO2 and elevated O3 alter resistance of soybean (Glycine max) to Japanese beetles (Popillia japonica).

PubMed

Casteel, Clare L; O'Neill, Bridget F; Zavala, Jorge A; Bilgin, Damla D; Berenbaum, May R; Delucia, Evan H

2008-04-01

The accumulation of CO2 and O3 in the troposphere alters phytochemistry which in turn influences the interactions between plants and insects. Using microarray analysis of field-grown soybean (Glycine max), we found that the number of transcripts in the leaves affected by herbivory by Japanese beetles (Popillia japonica) was greater when plants were grown under elevated CO2, elevated O3 and the combination of elevated CO2 plus elevated O3 than when grown in ambient atmosphere. The effect of herbivory on transcription diminished strongly with time (<1% of genes were affected by herbivory after 3 weeks), and elevated CO2 interacted more strongly with herbivory than elevated O3. The majority of transcripts affected by elevated O3 were related to antioxidant metabolism. Constitutive levels and the induction by herbivory of key transcripts associated with defence and hormone signalling were down-regulated under elevated CO2; 1-aminocyclopropane-1-carboxylate (ACC) synthase, lipoxygenase (LOX), allene oxide synthase (AOS), allene oxide cyclase (AOC), chalcone synthase (CHS), polyphenol oxidase (PPO) and cysteine protease inhibitor (CystPI) were lower in abundance compared with levels under ambient conditions. By suppressing the ability to mount an effective defence, elevated CO2 may decrease resistance of soybean to herbivory.

Structural Analysis of a β-Helical Protein Motif Stabilized by Targeted Replacements with Conformationally Constrained Amino Acids

PubMed Central

Ballano, Gema; Zanuy, David; Jiménez, Ana I.; Cativiela, Carlos; Nussinov, Ruth; Alemán, Carlos

2009-01-01

Here we study conformational stabilization induced in a β-helical nanostructure by position-specific mutations. The nanostructure is constructed through the self-assembly of the β-helical building block excised from E. coli galactoside acetyltransferase (PDB code 1krr, chain A; residues 131-165). The mutations involve substitutions by cyclic, conformationally constrained amino acids. Specifically, a complete structural analysis of the Pro-Xaa-Val sequence [with Xaa being Gly, Ac3c (1-aminocyclopropane-1-carboxylic acid) and Ac5c (1-aminocyclopentane-1-carboxylic acid)], corresponding to the 148-150 loop region in the wild-type (Gly) and mutated (Ac3c and Ac5c) 1krr, has been performed using Molecular Dynamics simulations and X-ray crystallography. Simulations have been performed for the wild-type and mutants of three different systems, namely the building block, the nanoconstruct and the isolated Pro-Xaa-Val tripeptide. Furthermore, the crystalline structures of five peptides of Pro-Xaa-Val or Xaa-Val sequences have been solved by X-ray diffraction analysis and compared with theoretical predictions. Both the theoretical and crystallographic studies indicate that the Pro-Acnc-Val sequences exhibit a high propensity to adopt turn-like conformations, and this propensity is little affected by the chemical environment. Overall, the results indicate that replacement of Gly149 by Ac3c or Ac5c significantly reduce the conformational flexibility of the target site enhancing the structural specificity of the building block and the nanoconstruct derived from the 1krr β-helical motif. PMID:18811190

Alleviation of salt stress by enterobacter sp. EJ01 in tomato and Arabidopsis is accompanied by up-regulation of conserved salinity responsive factors in plants.

PubMed

Kim, Kangmin; Jang, Ye-Jin; Lee, Sang-Myeong; Oh, Byung-Taek; Chae, Jong-Chan; Lee, Kui-Jae

2014-02-01

Microbiota in the niches of the rhizosphere zones can affect plant growth and responses to environmental stress conditions via mutualistic interactions with host plants. Specifically, some beneficial bacteria, collectively referred to as Plant Growth Promoting Rhizobacteria (PGPRs), increase plant biomass and innate immunity potential. Here, we report that Enterobacter sp. EJ01, a bacterium isolated from sea china pink (Dianthus japonicus thunb) in reclaimed land of Gyehwa-do in Korea, improved the vegetative growth and alleviated salt stress in tomato and Arabidopsis. EJ01 was capable of producing 1-aminocy-clopropane-1-carboxylate (ACC) deaminase and also exhibited indole-3-acetic acid (IAA) production. The isolate EJ01 conferred increases in fresh weight, dry weight, and plant height of tomato and Arabidopsis under both normal and high salinity conditions. At the molecular level, short-term treatment with EJ01 increased the expression of salt stress responsive genes such as DREB2b, RD29A, RD29B, and RAB18 in Arabidopsis. The expression of proline biosynthetic genes (i.e. P5CS1 and P5CS2) and of genes related to priming processes (i.e. MPK3 and MPK6) were also up-regulated. In addition, reactive oxygen species scavenging activities were enhanced in tomatoes treated with EJ01 in stressed conditions. GFP-tagged EJ01 displayed colonization in the rhizosphere and endosphere in the roots of Arabidopsis. In conclusion, the newly isolated Enterobacter sp. EJ01 is a likely PGPR and alleviates salt stress in host plants through multiple mechanisms, including the rapid up-regulation of conserved plant salt stress responsive signaling pathways.

Alleviation of Salt Stress by Enterobacter sp. EJ01 in Tomato and Arabidopsis Is Accompanied by Up-Regulation of Conserved Salinity Responsive Factors in Plants

PubMed Central

Kim, Kangmin; Jang, Ye-Jin; Lee, Sang-Myeong; Oh, Byung-Taek; Chae, Jong-Chan; Lee, Kui-Jae

2014-01-01

Microbiota in the niches of the rhizosphere zones can affect plant growth and responses to environmental stress conditions via mutualistic interactions with host plants. Specifically, some beneficial bacteria, collectively referred to as Plant Growth Promoting Rhizobacteria (PGPRs), increase plant biomass and innate immunity potential. Here, we report that Enterobacter sp. EJ01, a bacterium isolated from sea china pink (Dianthus japonicus thunb) in reclaimed land of Gyehwa-do in Korea, improved the vegetative growth and alleviated salt stress in tomato and Arabidopsis. EJ01 was capable of producing 1-aminocy-clopropane-1-carboxylate (ACC) deaminase and also exhibited indole-3-acetic acid (IAA) production. The isolate EJ01 conferred increases in fresh weight, dry weight, and plant height of tomato and Arabidopsis under both normal and high salinity conditions. At the molecular level, short-term treatment with EJ01 increased the expression of salt stress responsive genes such as DREB2b, RD29A, RD29B, and RAB18 in Arabidopsis. The expression of proline biosynthetic genes (i.e. P5CS1 and P5CS2) and of genes related to priming processes (i.e. MPK3 and MPK6) were also up-regulated. In addition, reactive oxygen species scavenging activities were enhanced in tomatoes treated with EJ01 in stressed conditions. GFP-tagged EJ01 displayed colonization in the rhizosphere and endosphere in the roots of Arabidopsis. In conclusion, the newly isolated Enterobacter sp. EJ01 is a likely PGPR and alleviates salt stress in host plants through multiple mechanisms, including the rapid up-regulation of conserved plant salt stress responsive signaling pathways. PMID:24598995

Characterization of plant growth-promoting traits of free-living diazotrophic bacteria and their inoculation effects on growth and nitrogen uptake of crop plants.

PubMed

Islam, Md Rashedul; Madhaiyan, M; Deka Boruah, Hari P; Yim, Woojong; Lee, Gillseung; Saravanan, V S; Fu, Qingling; Hu, Hongqing; Sa, Tongmin

2009-10-01

The search for diverse plant growth-promoting (PGP) diazotrophic bacteria is gaining momentum as efforts are made to exploit them as biofertilizers for various economically important crops. In the present study, 17 diazotrophic strains belonging to eight different genera isolated from rice paddy fields were screened for multiple PGP traits and evaluated for their inoculation effects on canola and rice plants. All of the strains tested positive for 1- aminocyclopropane-1-carboxylate (ACC) deaminase activity and production of indole 3-acetic acid (IAA) and ammonia (NH3). Additionally, four of the strains were able to solubilize phosphorus (P), five tested positive for zinc (Zn) solubilization and sulfur (S) oxidation, and eight strains produced siderophores. Based on the presence of multiple PGP traits, 10 strains were selected for inoculation studies. Treatment with Herbaspirillum sp. RFNB26 resulted in maximum root length (54.3%), seedling vigor, and dry biomass in canola, whereas Paenibacillus sp. RFNB4 exhibited the lowest activity under gnotobiotic conditions. However, under pot culture conditions, Paenibacillus sp. RFNB4 significantly increased plant height and dry biomass production by 42.3% and 29.5%, respectively. Canola plants and rhizosphere soils inoculated with Bacillus sp. RFNB6 exhibited significantly higher nitrogenase activity. In greenhouse experiments, Serratia sp. RFNB18 increased rice plant height by 35.1%, Xanthomonas sp. RFNB24 enhanced biomass production by 84.6%, and rice rhizosphere soils inoculated with Herbaspirillum sp. RFNB26 exhibited the highest nitrogenase activity. Our findings indicate that most of the selected strains possess multiple PGP properties that significantly improve the growth parameters of the two plants when tested under controlled conditions.

Methyl jasmonate-induced defense responses are associated with elevation of 1-aminocyclopropane-1-carboxylate oxidase in Lycopersicon esculentum fruit.

PubMed

Yu, Mengmeng; Shen, Lin; Zhang, Aijun; Sheng, Jiping

2011-10-15

It has been known that methyl jasmonate (MeJA) interacts with ethylene to elicit resistance. In green mature tomato fruits (Lycopersicon esculentum cv. Lichun), 0.02mM MeJA increased the activity of 1-aminocyclopropane-1-carboxylate oxidase (ACO), and consequently influenced the last step of ethylene biosynthesis. Fruits treated with a combination of 0.02 MeJA and 0.02 α-aminoisobutyric acid (AIB, a competitive inhibitor of ACO) exhibited a lower ethylene production comparing to that by 0.02mM MeJA alone. The increased activities of defense enzymes and subsequent control of disease incidence caused by Botrytis cinerea with 0.2mM MeJA treatment was impaired by AIB as well. A close relationship (P<0.05) was found between the activity alterations of ACO and that of chitinase (CHI) and β-1,3-glucanase (GLU). In addition, this study further detected the changes of gene expressions and enzyme kinetics of ACO to different concentrations of MeJA. LeACO1 was found the principal member from the ACO gene family to respond to MeJA. Accumulation of LeACO1/3/4 transcripts followed the concentration pattern of MeJA treatments, where the largest elevations were reached by 0.2mM. For kinetic analysis, K(m) values of ACO stepped up during the experiment and reached the maximums at 0.2mM MeJA with ascending concentrations of treatments. V(max) exhibited a gradual increase from 3h to 24h, and the largest induction appeared with 1.0mM MeJA. The results suggested that ACO is involved in MeJA-induced resistance in tomato, and the concentration influence of MeJA on ACO was attributable to the variation of gene transcripts and enzymatic properties. Copyright © 2011 Elsevier GmbH. All rights reserved.

Jasmonates act positively in adventitious root formation in petunia cuttings.

PubMed

Lischweski, Sandra; Muchow, Anne; Guthörl, Daniela; Hause, Bettina

2015-09-22

Petunia is a model to study the process of adventitious root (AR) formation on leafy cuttings. Excision of cuttings leads to a transient increase in jasmonates, which is regarded as an early, transient and critical event for rooting. Here, the role of jasmonates in AR formation on petunia cuttings has been studied by a reverse genetic approach. To reduce the endogenous levels of jasmonates, transgenic plants were generated expressing a Petunia hybrida ALLENE OXIDE CYCLASE (PhAOC)-RNAi construct. The transgenic plants exhibited strongly reduced PhAOC transcript and protein levels as well as diminished accumulation of cis-12-oxo-phytodienoic acid, jasmonic acid and jasmonoyl-isoleucine after wounding in comparison to wild type and empty vector expressing plants. Reduced levels of endogenous jasmonates resulted in formation of lower numbers of ARs. However, this effect was not accompanied by altered levels of auxin and aminocyclopropane carboxylate (ACC, precursor of ethylene) or by impaired auxin and ethylene-induced gene expression. Neither activity of cell-wall invertases nor accumulation of soluble sugars was altered by jasmonate deficiency. Diminished numbers of AR in JA-deficient cuttings suggest that jasmonates act as positive regulators of AR formation in petunia wild type. However, wound-induced rise in jasmonate levels in petunia wild type cuttings seems not to be causal for increased auxin and ethylene levels and for sink establishment.

Ethylene: Indicator but Not Inducer of Phytoalexin Synthesis in Soybean 1

PubMed Central

Paradies, Inge; Konze, Jörg R.; Elstner, Erich F.; Paxton, Jack

1980-01-01

Cell wall preparations (elicitors) from Phytophthora megasperma var. sojae increase C2H4 formation, phenylalanine ammonia lyase activity, and glyceollin accumulation in soybean cotyledons within about 1.5, 3, and 6 hours after treatment, respectively. The immediate precursor of C2H4, 1-aminocyclopropane-1-carboxylic acid, stimulates C2H4 formation like the elicitor within 1.5 hours after administration, whereas phenylalanine ammonia lyase activity and glyceollin concentration remain unchanged. Aminoethoxyvinylglycine, a specific inhibitor of C2H4 formation in higher plants, inhibits elicitor-induced C2H4 formation by about 95% but has no effects on phenylalanine ammonia lyase or glyceollin accumulation. It was concluded that C2H4 is a signal accompanying the specific recognition process which finally leads to the induction of phytoalexin formation, but it is not functioning as a link or messenger in the induction sequence of glyceollin accumulation. Images PMID:16661585

Effects of Ethylene on Seed Germination of Halophyte Plants Under Salt Stress.

PubMed

Li, Weiqiang; Tran, Lam-Son Phan

2017-01-01

Halophyte plant species are those that can finish their life cycle in the presence of 50% or more seawater concentration. Ethylene, as a natural plant hormone produced at later stages of seed germination, plays an important role in regulating seed germination. However, its regulatory role in seed dormancy and germination of halophyte plants under salt stress is still not well understood. In this chapter, we describe methods used for applications of two ethylene donors, ethephon and 1-aminocyclopropane-1-carboxylic acid, in studies aimed at examining the effects of ethylene on seed germination of a representative halophyte plant Suaeda salsa under high salinity. Similar approaches can be applied to the study of ethylene and salt interactions in other plant species, when taking into account that salt sensitivities may differ.

Ethylene Upregulates Auxin Biosynthesis in Arabidopsis Seedlings to Enhance Inhibition of Root Cell Elongation[W

PubMed Central

Swarup, Ranjan; Perry, Paula; Hagenbeek, Dik; Van Der Straeten, Dominique; Beemster, Gerrit T.S.; Sandberg, Göran; Bhalerao, Rishikesh; Ljung, Karin; Bennett, Malcolm J.

2007-01-01

Ethylene represents an important regulatory signal for root development. Genetic studies in Arabidopsis thaliana have demonstrated that ethylene inhibition of root growth involves another hormone signal, auxin. This study investigated why auxin was required by ethylene to regulate root growth. We initially observed that ethylene positively controls auxin biosynthesis in the root apex. We subsequently demonstrated that ethylene-regulated root growth is dependent on (1) the transport of auxin from the root apex via the lateral root cap and (2) auxin responses occurring in multiple elongation zone tissues. Detailed growth studies revealed that the ability of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid to inhibit root cell elongation was significantly enhanced in the presence of auxin. We conclude that by upregulating auxin biosynthesis, ethylene facilitates its ability to inhibit root cell expansion. PMID:17630275

The ethylene response factor AtERF4 negatively regulates the iron deficiency response in Arabidopsis thaliana

PubMed Central

Liu, Wei; Karemera, N. J. Umuhoza; Wu, Ting; Yang, Yafei; Zhang, Xinzhong; Xu, Xuefeng; Han, Zhenhai

2017-01-01

Iron (Fe) deficiency is one of many conditions that can seriously damage crops. Low levels of photosynthesis can lead to the degradation of chlorophyll content and impaired respiration in affected plants, which together cause poor growth and reduce quality. Although ethylene plays an important role in responses to Fe deficiency, a limited number of studies have been carried out on ethylene response factor (ERFs) as components of plant regulation mechanisms. Thus, this study aimed to investigate the role of AtERF4 in plant responses to Fe deficiency. Results collected when Arabidopsis thaliana was grown under Fe deficient conditions as well as in the presence of 1-aminocyclopropane-1-carboxylic acid (ACC) revealed that leaf chlorosis did not occur over short timescales and that chloroplast structural integrity was retained. At the same time, expression of the chlorophyll degradation-related genes AtPAO and AtCLH1 was inhibited and net H+ root flux was amplified. Our results show that chlorophyll content was enhanced in the mutant erf4, while expression of the chlorophyll degradation gene AtCLH1 was reduced. Ferric reductase activity in roots was also significantly higher in the mutant than in wild type plants, while erf4 caused high levels of expression of the genes AtIRT1 and AtHA2 under Fe deficient conditions. We also utilized yeast one-hybrid technology in this study to determine that AtERF4 binds directly to the AtCLH1 and AtITR1 promoter. Observations show that transient over-expression of AtERF4 resulted in rapid chlorophyll degradation in the leaves of Nicotiana tabacum and the up-regulation of gene AtCLH1 expression. In summary, AtERF4 plays an important role as a negative regulator of Fe deficiency responses, we hypothesize that AtERF4 may exert a balancing effect on plants subject to nutrition stress. PMID:29045490

The ethylene response factor AtERF4 negatively regulates the iron deficiency response in Arabidopsis thaliana.

PubMed

Liu, Wei; Karemera, N J Umuhoza; Wu, Ting; Yang, Yafei; Zhang, Xinzhong; Xu, Xuefeng; Wang, Yi; Han, Zhenhai

2017-01-01

Iron (Fe) deficiency is one of many conditions that can seriously damage crops. Low levels of photosynthesis can lead to the degradation of chlorophyll content and impaired respiration in affected plants, which together cause poor growth and reduce quality. Although ethylene plays an important role in responses to Fe deficiency, a limited number of studies have been carried out on ethylene response factor (ERFs) as components of plant regulation mechanisms. Thus, this study aimed to investigate the role of AtERF4 in plant responses to Fe deficiency. Results collected when Arabidopsis thaliana was grown under Fe deficient conditions as well as in the presence of 1-aminocyclopropane-1-carboxylic acid (ACC) revealed that leaf chlorosis did not occur over short timescales and that chloroplast structural integrity was retained. At the same time, expression of the chlorophyll degradation-related genes AtPAO and AtCLH1 was inhibited and net H+ root flux was amplified. Our results show that chlorophyll content was enhanced in the mutant erf4, while expression of the chlorophyll degradation gene AtCLH1 was reduced. Ferric reductase activity in roots was also significantly higher in the mutant than in wild type plants, while erf4 caused high levels of expression of the genes AtIRT1 and AtHA2 under Fe deficient conditions. We also utilized yeast one-hybrid technology in this study to determine that AtERF4 binds directly to the AtCLH1 and AtITR1 promoter. Observations show that transient over-expression of AtERF4 resulted in rapid chlorophyll degradation in the leaves of Nicotiana tabacum and the up-regulation of gene AtCLH1 expression. In summary, AtERF4 plays an important role as a negative regulator of Fe deficiency responses, we hypothesize that AtERF4 may exert a balancing effect on plants subject to nutrition stress.

Elucidating the Mechanisms of the Tomato ovate Mutation in Regulating Fruit Quality Using Proteomics Analysis.

PubMed

Liu, Juhua; Zhang, Jing; Miao, Hongxia; Jia, Caihong; Wang, Jingyi; Xu, Biyu; Jin, Zhiqiang

2017-11-22

The ovate mutation has frequently been used to study changes in fruit shape but not fruit quality. A deterioration in fruit quality associated with the ovate mutation was discovered in this study. To elucidate how ovate influences the quality of fruit, we performed a proteomics analysis of the fruits of the ovate mutant (LA3543) and wild-type ("Ailsa Craig", LA2838A) using tandem mass tag analysis. The results indicated that the ovate mutation significantly influences fruit quality in a number of ways, including by reducing the expression of 1-aminocyclopropane-1-carboxylic acid oxidase 3 (ACO3) in ethylene biosynthesis, improving firmness by reducing the amount of pectinesterase and polygalacturonase, reducing sugar accumulation by downregulating the abundance of mannan endo-1,4-β-mannosidase 4, β-galactosidase, and β-amylase, and reducing the malic acid content by downregulating the accumulation of malic enzymes and malate synthase. These findings could inform future improvements in fruit quality.

Application of Endophytic Pseudomonas fluorescens and a Bacterial Consortium to Brassica napus Can Increase Plant Height and Biomass under Greenhouse and Field Conditions

PubMed Central

Lally, Richard D.; Galbally, Paul; Moreira, António S.; Spink, John; Ryan, David; Germaine, Kieran J.; Dowling, David N.

2017-01-01

Plant associated bacteria with plant growth promotion (PGP) properties have been proposed for use as environmentally friendly biofertilizers for sustainable agriculture; however, analysis of their efficacy in the field is often limited. In this study, greenhouse and field trials were carried out using individual endophytic Pseudomonas fluorescens strains, the well characterized rhizospheric P. fluorescens F113 and an endophytic microbial consortium of 10 different strains. These bacteria had been previously characterized with respect to their PGP properties in vitro and had been shown to harbor a range of traits associated with PGP including siderophore production, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, and inorganic phosphate solubilization. In greenhouse experiments individual strains tagged with gfp and Kmr were applied to Brassica napus as a seed coat and were shown to effectively colonize the rhizosphere and root of B. napus and in addition they demonstrated a significant increase in plant biomass compared with the non-inoculated control. In the field experiment, the bacteria (individual and consortium) were spray inoculated to winter oilseed rape B. napus var. Compass which was grown under standard North Western European agronomic conditions. Analysis of the data provides evidence that the application of the live bacterial biofertilizers can enhance aspects of crop development in B. napus at field scale. The field data demonstrated statistically significant increases in crop height, stem/leaf, and pod biomass, particularly, in the case of the consortium inoculated treatment. However, although seed and oil yield were increased in the field in response to inoculation, these data were not statistically significant under the experimental conditions tested. Future field trials will investigate the effectiveness of the inoculants under different agronomic conditions. PMID:29312422

Physiological and biochemical perspectives of non-salt tolerant plants during bacterial interaction against soil salinity.

PubMed

Radhakrishnan, Ramalingam; Baek, Kwang Hyun

2017-07-01

Climatic changes on earth affect the soil quality of agricultural lands, especially by increasing salt deposition in soil, which results in soil salinity. Soil salinity is a major challenge to growth and reproduction among glycophytes (including all crop plants). Soil bacteria present in the rhizosphere and/or roots naturally protect plants from the adverse effects of soil salinity by reprogramming the stress-induced physiological changes in plants. Bacteria can enrich the soil with major nutrients (nitrogen, phosphorus, and potassium) in a form easily available to plants and prevent the transport of excess sodium to roots (exopolysaccharides secreted by bacteria bind with sodium ions) for maintaining ionic balance and water potential in cells. Salinity also affects plant growth regulators and suppresses seed germination and root and shoot growth. Bacterial secretion of indole-3-acetic acid and gibberellins compensates for the salt-induced hormonal decrease in plants, and bacterial 1-aminocyclopropane-1-carboxylate (ACC) deaminase synthesis decreases ethylene production to stimulate plant growth. Furthermore, bacteria modulate the redox state of salinity-affected plants by enhancing antioxidants and polyamines, which leads to increased photosynthetic efficiency. Bacteria-induced accumulation of compatible solutes in stressed plants regulates plant cellular activities and prevents salt stress damage. Plant-bacterial interaction reprograms the expression of salt stress-responsive genes and proteins in salinity-affected plants, resulting in a precise stress mitigation metabolism as a defense mechanism. Soil bacteria increase the fertility of soil and regulate the plant functions to prevent the salinity effects in glycophytes. This review explains the current understanding about the physiological changes induced in glycophytes during bacterial interaction to alleviate the adverse effects of soil salinity stress. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

The role of gravity in apical dominance: effects of clinostating on shoot inversion-induced ethylene production, shoot elongation and lateral bud growth

NASA Technical Reports Server (NTRS)

Prasad, T. K.; Cline, M. G.

1987-01-01

Shoot inversion-induced release of apical dominance in Pharbitis nil is inhibited by rotating the plant at 0.42 revolutions per minute in a vertical plane perpendicular to the axis of rotation of a horizontal clinostat. Clinostating prevented lateral bud outgrowth, apparently by negating the restriction of the shoot elongation via reduction of ethylene production in the inverted shoot. Radial stem expansion was also decreased. Data from experiments with intact tissue and isolated segments indicated that shoot-inversion stimulates ethylene production by increasing the activity of 1-aminocyclopropane-1-carboxylic acid synthase. The results support the hypothesis that shoot inversion-induced release of apical dominance in Pharbitis nil is due to gravity stress and is mediated by ethylene-induced retardation of the elongation of the inverted shoot.

Interactions between ethylene and auxin are crucial to the control of grape (Vitis vinifera L.) berry ripening.

PubMed

Böttcher, Christine; Burbidge, Crista A; Boss, Paul K; Davies, Christopher

2013-12-23

Fruit development is controlled by plant hormones, but the role of hormone interactions during fruit ripening is poorly understood. Interactions between ethylene and the auxin indole-3-acetic acid (IAA) are likely to be crucial during the ripening process, since both hormones have been shown to be implicated in the control of ripening in a range of different fruit species. Grapevine (Vitis vinifera L.) homologues of the TRYPTOPHAN AMINOTRANSFERASE RELATED (TAR) and YUCCA families, functioning in the only characterized pathway of auxin biosynthesis, were identified and the expression of several TAR genes was shown to be induced by the pre-ripening application of the ethylene-releasing compound Ethrel. The induction of TAR expression was accompanied by increased IAA and IAA-Asp concentrations, indicative of an upregulation of auxin biosynthesis and conjugation. Exposure of ex planta, pre-ripening berries to the ethylene biosynthesis inhibitor aminoethoxyvinylglycine resulted in decreased IAA and IAA-Asp concentrations. The delayed initiation of ripening observed in Ethrel-treated berries might therefore represent an indirect ethylene effect mediated by increased auxin concentrations. During berry development, the expression of three TAR genes and one YUCCA gene was upregulated at the time of ripening initiation and/or during ripening. This increase in auxin biosynthesis gene expression was preceded by high expression levels of the ethylene biosynthesis genes 1-aminocyclopropane-1-carboxylate synthase and 1-aminocyclopropane-1-carboxylate oxidase. In grape berries, members of both gene families involved in the two-step pathway of auxin biosynthesis are expressed, suggesting that IAA is produced through the combined action of TAR and YUCCA proteins in developing berries. The induction of TAR expression by Ethrel applications and the developmental expression patterns of auxin and ethylene biosynthesis genes indicate that elevated concentrations of ethylene prior to the initiation of ripening might lead to an increased production of IAA, suggesting a complex involvement of this auxin and its conjugates in grape berry ripening.

Interactions between ethylene and auxin are crucial to the control of grape (Vitis vinifera L.) berry ripening

PubMed Central

2013-01-01

Background Fruit development is controlled by plant hormones, but the role of hormone interactions during fruit ripening is poorly understood. Interactions between ethylene and the auxin indole-3-acetic acid (IAA) are likely to be crucial during the ripening process, since both hormones have been shown to be implicated in the control of ripening in a range of different fruit species. Results Grapevine (Vitis vinifera L.) homologues of the TRYPTOPHAN AMINOTRANSFERASE RELATED (TAR) and YUCCA families, functioning in the only characterized pathway of auxin biosynthesis, were identified and the expression of several TAR genes was shown to be induced by the pre-ripening application of the ethylene-releasing compound Ethrel. The induction of TAR expression was accompanied by increased IAA and IAA-Asp concentrations, indicative of an upregulation of auxin biosynthesis and conjugation. Exposure of ex planta, pre-ripening berries to the ethylene biosynthesis inhibitor aminoethoxyvinylglycine resulted in decreased IAA and IAA-Asp concentrations. The delayed initiation of ripening observed in Ethrel-treated berries might therefore represent an indirect ethylene effect mediated by increased auxin concentrations. During berry development, the expression of three TAR genes and one YUCCA gene was upregulated at the time of ripening initiation and/or during ripening. This increase in auxin biosynthesis gene expression was preceded by high expression levels of the ethylene biosynthesis genes 1-aminocyclopropane-1-carboxylate synthase and 1-aminocyclopropane-1-carboxylate oxidase. Conclusions In grape berries, members of both gene families involved in the two-step pathway of auxin biosynthesis are expressed, suggesting that IAA is produced through the combined action of TAR and YUCCA proteins in developing berries. The induction of TAR expression by Ethrel applications and the developmental expression patterns of auxin and ethylene biosynthesis genes indicate that elevated concentrations of ethylene prior to the initiation of ripening might lead to an increased production of IAA, suggesting a complex involvement of this auxin and its conjugates in grape berry ripening. PMID:24364881

Analysis of genomic DNA of DcACS1, a 1-aminocyclopropane-1-carboxylate synthase gene, expressed in senescing petals of carnation (Dianthus caryophyllus) and its orthologous genes in D. superbus var. longicalycinus.

PubMed

Harada, Taro; Murakoshi, Yuino; Torii, Yuka; Tanase, Koji; Onozaki, Takashi; Morita, Shigeto; Masumura, Takehiro; Satoh, Shigeru

2011-04-01

Carnation (Dianthus caryophyllus) flowers exhibit climacteric ethylene production followed by petal wilting, a senescence symptom. DcACS1, which encodes 1-aminocyclopropane-1-carboxylate synthase (ACS), is a gene involved in this phenomenon. We determined the genomic DNA structure of DcACS1 by genomic PCR. In the genome of 'Light Pink Barbara', we found two distinct nucleotide sequences: one corresponding to the gene previously shown as DcACS1, designated here as DcACS1a, and the other novel one designated as DcACS1b. It was revealed that both DcACS1a and DcACS1b have five exons and four introns. These two genes had almost identical nucleotide sequences in exons, but not in some introns and 3'-UTR. Analysis of transcript accumulation revealed that DcACS1b is expressed in senescing petals as well as DcACS1a. Genomic PCR analysis of 32 carnation cultivars showed that most cultivars have only DcACS1a and some have both DcACS1a and DcACS1b. Moreover, we found two DcACS1 orthologous genes with different nucleotide sequences from D. superbus var. longicalycinus, and designated them as DsuACS1a and DsuACS1b. Petals of D. superbus var. longicalycinus produced ethylene in response to exogenous ethylene, accompanying accumulation of DsuACS1 transcripts. These data suggest that climacteric ethylene production in flowers was genetically established before the cultivation of carnation.

Molecular Characterization of Lactobacillus plantarum Genes for β-Ketoacyl-Acyl Carrier Protein Synthase III (fabH) and Acetyl Coenzyme A Carboxylase (accBCDA), Which Are Essential for Fatty Acid Biosynthesis

PubMed Central

Kiatpapan, Pornpimon; Kobayashi, Hajime; Sakaguchi, Maki; Ono, Hisayo; Yamashita, Mitsuo; Kaneko, Yoshinobu; Murooka, Yoshikatsu

2001-01-01

Genes for subunits of acetyl coenzyme A carboxylase (ACC), which is the enzyme that catalyzes the first step in the synthesis of fatty acids in Lactobacillus plantarum L137, were cloned and characterized. We identified six potential open reading frames, namely, manB, fabH, accB, accC, accD, and accA, in that order. Nucleotide sequence analysis suggested that fabH encoded β-ketoacyl-acyl carrier protein synthase III, that the accB, accC, accD, and accA genes encoded biotin carboxyl carrier protein, biotin carboxylase, and the β and α subunits of carboxyltransferase, respectively, and that these genes were clustered. The organization of acc genes was different from that reported for Escherichia coli, for Bacillus subtilis, and for Pseudomonas aeruginosa. E. coli accB and accD mutations were complemented by the L. plantarum accB and accD genes, respectively. The predicted products of all five genes were confirmed by using the T7 expression system in E. coli. The gene product of accB was biotinylated in E. coli. Northern and primer extension analyses demonstrated that the five genes in L. plantarum were regulated polycistronically in an acc operon. PMID:11133475

Isolation and characterization of novel plant growth promoting Micrococcus sp NII-0909 and its interaction with cowpea.

PubMed

Dastager, Syed G; Deepa, C K; Pandey, Ashok

2010-12-01

A phosphate-solubilizing bacterial strain NII-0909 isolated from the Western ghat forest soil in India was identified as Micrococcus sp on the basis of phenotypic characteristics, carbon source utilization pattern, fatty acid methyl esters analysis, and 16S rRNA gene sequence. The strain exhibited the plant growth-promoting attributes of phosphate solubilization, auxin production, 1-aminocyclopropane-1-carboxylate deaminase activity, and siderophore production. It was able to solubilize (122.4μg of Ca(3)PO(4) ml(-1)), and produce IAA (109μgml(-1)) at 30°C. P-solubilizing activity of the strain NII-0909 was associated with the release of organic acids and a drop in the pH of the NBRIP medium. HPLC analysis detected two organic acids in the course of P-solubilization. A significant increase in the growth of cow pea was recorded for inoculations under controlled conditions. Scanning electron microscopic study revealed the root colonization of strain on cow pea seedlings. These results demonstrate that isolates NII-0909 has the promising PGPR attributes to be develop as a biofertilizer to enhance soil fertility and promote the plant growth. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

Superficial scald and bitter pit development in cold-stored transgenic apples suppressed for ethylene biosynthesis.

PubMed

Pesis, Edna; Ibáñez, Ana M; Phu, My Lin; Mitcham, Elizabeth J; Ebeler, Susan E; Dandekar, Abhaya M

2009-04-08

The plant hormone ethylene regulates climacteric fruit ripening and plays a major role in the development of superficial scald in apple fruits during cold storage. The effect of cold storage at 0 degrees C on development of superficial scald and bitter pit (BP) in transgenic Greensleeves (GS) apples suppressed for ethylene biosynthesis was investigated. Four apple lines were used: untransformed GS; line 68G, suppressed for 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase (ACO); and lines 103Yand 130Y, suppressed for ACC synthase (ACS). Fruits from the transformed lines 68G, 103Y, and 130Y produced very little ethylene during 3 months of cold storage at 0 degrees C and after subsequent transfer to 20 degrees C, whereas untransformed fruits produced significant ethylene during cold storage, which increased dramatically at 20 degrees C. Respiration, expressed as CO(2) production, was similar in all four apple lines. After 2 months at 0 degrees C, all apple lines showed some BP symptoms, but lines 68G and 103Y were more affected than untransformed GS or line 130Y. Both transformed and untransformed apples produced alpha-farnesene, but concentrations were lower in yellow fruit than in green fruit in all lines but 68G. Line 68G produced the most alpha-farnesene after 2 months at 0 degrees C, including both (E,E) alpha-farnesene and (Z,E) alpha-farnesene. Concentrations of (E,E) alpha-farnesene were 100 times greater than those of (Z,E) alpha-farnesene in all lines. After 4 months at 0 degrees C plus 1 week at 20 degrees C, untransformed GS apples exhibited the most superficial scald, whereas fruits from lines 68G and 103Y were less affected and line 130Y had no scald. Superficial scald severity was higher in green fruit than in yellow fruit in all affected lines. These lines also exhibited significant production of 6-methyl-5-hepten-2-one (MHO), a major oxidation product of (E,E) alpha-farnesene. Line 130Y neither exhibited superficial scald nor produced MHO. It is shown here that even transgenic apples suppressed for ethylene biosynthesis genes can produce alpha-farnesene, which in turn can oxidize to free radicals and MHO, leading to scald development.

Ethylene Is Not Responsible for Phytochrome-Mediated Apical Hook Exaggeration in Tomato

PubMed Central

Takahashi-Asami, Miki; Shichijo, Chizuko; Tsurumi, Seiji; Hashimoto, Tohru

2016-01-01

The apical hook of tomato seedlings is exaggerated by phytochrome actions, while in other species such as bean, pea and Arabidopsis, the hook is exaggerated by ethylene and opens by phytochrome actions. The present study was aimed to clarify mainly whether ethylene is responsible for the phytochrome-mediated hook exaggeration of tomato seedlings. Dark-grown 5-day-old seedlings were subjected to various ways of ethylene application in the dark as well as under the actions of red (R) or far-red light (FR). The ethylene emitted by seedlings was also quantified relative to hook exaggeration. The results show: Ambient ethylene, up-to about 1.0 μL L-1, suppressed (opened) the hooks formed in the dark as well as the ones exaggerated by R or FR, while at 3.0–10 μL L-1 it enhanced (closed) the hook only slightly as compared with the most-suppressed level at about 1.0 μL L-1. Treatment with 1-aminocyclopropane-1-carboxylic acid (ACC), the immediate precursor of ethylene biosynthesis, did not enhance the hook, only mimicking the suppressive effects of ambient ethylene. The biosynthesis inhibitor, CoCl2 or aminoethoxyvinylglycine, enhanced hook curvature, and the enhancement was canceled by supplement of ethylene below 1.0 μL L-1. Auxin transport inhibitor, N-1-naphthylphthalamic acid, by contrast, suppressed curvature markedly without altering ethylene emission. The effects of the above-stated treatments did not differentiate qualitatively among the R-, FR-irradiated seedlings and dark control so as to explain phytochrome-mediated hook exaggeration. In addition, ethylene emission by seedlings was affected neither by R nor FR at such fluences as to cause hook exaggeration. In conclusion, (1) ethylene suppresses not only the light-exaggerated hook, but also the dark-formed one; (2) ethylene emission is not affected by R or FR, and also not correlated with the hook exaggerations; thus ethylene is not responsible for the hook exaggeration in tomato; and (3) auxin is essential for the maintenance and development of the hook in tomato as is the case in other species lacking phytochrome-mediated hook exaggeration. A possible mechanism of phytochrome action for hook exaggeration is discussed. PMID:27933077

Chromium downregulates the expression of Acetyl CoA Carboxylase 1 gene in lipogenic tissues of domestic goats: a potential strategy for meat quality improvement.

PubMed

Najafpanah, Mohammad Javad; Sadeghi, Mostafa; Zali, Abolfazl; Moradi-Shahrebabak, Hossein; Mousapour, Hojatollah

2014-06-15

Acetyl CoA Carboxylase 1 (ACC1) is a biotin-dependent enzyme that catalyzes the carboxylation of Acetyl CoA to form Malonyl CoA, the key intermediate metabolite in fatty acid synthesis. In this study, the mRNA expression of the ACC1 gene was evaluated in four different tissues (liver, visceral fat, subcutaneous fat, and longissimus muscle) of the domestic goat (Capra hircus) kids feeding on four different levels of trivalent chromium (0, 0.5, 1, and 1.5mg/day) as food supplementation. RT-qPCR technique was used for expression analyses and heat shock protein 90 gene (HSP-90) was considered as reference gene for data normalization. Our results revealed that 1.5mg/day chromium significantly reduced the expression of the ACC1 gene in liver, visceral fat, and subcutaneous fat tissues, but not in longissimus muscles (P<0.05). We measured some phenotypic traits of kid's carcasses to detect their probable correlations with chromium-mediated downregulation of ACC1 expression. Interestingly, changes in ACC1 expression were accompanied with decreased accumulation of fats in adipose tissues such that the subcutaneous fat thickness and heart fat percentage decreased in kids feeding on chromium. By contrast, chromium supplemented kids showed higher percentage of muscles despite the fact that their total body weight did not differ from that of non-supplemented kids. Our study suggests that trivalent chromium alters the direction of energy accumulation towards muscles rather than fats and provides insights into application of chromium supplementation as a useful strategy for improvement of meat quality in domestic animals. Copyright © 2014 Elsevier B.V. All rights reserved.

Cytokinin, acting through ethylene, restores gravitropism to Arabidopsis seedlings grown under red light.

PubMed Central

Golan, A; Tepper, M; Soudry, E; Horwitz, B A; Gepstein, S

1996-01-01

Cytokinin replaces light in several aspects of the photomorphogenesis of dicot seedlings. Arabidopsis thaliana seedlings grown under red light have been shown to become disoriented, losing the negative hypocotyl gravitropism that has been observed in seedlings grown in darkness or white light. We report here that cytokinin at micromolar concentrations restores gravitropism to seedlings grown under red light. Cytokinin cancels the effect of red light on the gravity-sensing system and at the same time replaces light in the inhibition of hypocotyl elongation. Furthermore, application of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid acts similarly to cytokinin. Cytokinin cannot restore gravitropism under red light to an ethylene-insensitive mutant that is defective at the EIN2 locus. Stimulation of ethylene production, therefore, can explain the action of cytokinin in restoring negative gravitropism to the hypocotyls of Arabidopsis seedlings grown under continuous red light. PMID:8938401

Transcription of Biotic Stress Associated Genes in White Clover (Trifolium repens L.) Differs in Response to Cyst and Root-Knot Nematode Infection

PubMed Central

Islam, Afsana; Mercer, Chris F.; Leung, Susanna; Dijkwel, Paul P.

2015-01-01

The transcription of four members of the Kunitz proteinase inhibitor (KPI) gene family of white clover (Trifolium repens L.), designated as Tr-KPI1, Tr-KPI2, Tr-KPI4 and Tr-KPI5, was investigated at both local infection (roots) and systemic (leaf tissue) sites in white clover in response to infection with the clover root knot nematode (CRKN) Meloidogyne trifoliophila and the clover cyst nematode (CCN) Heterodera trifolii. Invasion by the CRKN resulted in a significant decrease in transcript abundance of Tr-KPI4 locally at both 4 days post-infection (dpi) and at 8 dpi, and an increase in transcription of Tr-KPI1 systemically at 8 dpi. In contrast, an increase in transcript abundance of all four Tr-KPI genes locally at 4 and 8 dpi, and an increase of Tr-KPI1, Tr-KPI2, and Tr-KPI5 at 8 dpi systemically was observed in response to infection with the CCN. Challenge of a resistant (R) genotype and a susceptible (S) genotype of white clover with the CCN revealed a significant increase in transcript abundance of all four Tr-KPI genes locally in the R genotype, while an increase in abundance of only Tr-KPI1, Tr-KPI2, and Tr-KPI5 was observed in the S genotype, and only at 4 dpi. The transcript abundance of a member of the1-AMINOCYCLOPROPANE-1-CARBOXYLATE (ACC) SYNTHASE gene family from white clover (Tr-ACS1) was significantly down-regulated locally in response to CRKN infection at 4 and 8 dpi and at 4 dpi, systemically, while abundance increased locally and systemically at 8 dpi in response to CCN challenge. Conversely, the abundance of the jasmonic acid (JA) signalling gene, CORONATINE-INSENSITIVE PROTEIN 1 from white clover (Tr-COI1) increased significantly at 8 dpi locally in response to CRKN infection, but decreased at 8 dpi in response to CCN infection. The significance of this differential regulation of transcription is discussed with respect to differences in infection strategy of the two nematode species. PMID:26393362

Transcription of Biotic Stress Associated Genes in White Clover (Trifolium repens L.) Differs in Response to Cyst and Root-Knot Nematode Infection.

PubMed

Islam, Afsana; Mercer, Chris F; Leung, Susanna; Dijkwel, Paul P; McManus, Michael T

2015-01-01

The transcription of four members of the Kunitz proteinase inhibitor (KPI) gene family of white clover (Trifolium repens L.), designated as Tr-KPI1, Tr-KPI2, Tr-KPI4 and Tr-KPI5, was investigated at both local infection (roots) and systemic (leaf tissue) sites in white clover in response to infection with the clover root knot nematode (CRKN) Meloidogyne trifoliophila and the clover cyst nematode (CCN) Heterodera trifolii. Invasion by the CRKN resulted in a significant decrease in transcript abundance of Tr-KPI4 locally at both 4 days post-infection (dpi) and at 8 dpi, and an increase in transcription of Tr-KPI1 systemically at 8 dpi. In contrast, an increase in transcript abundance of all four Tr-KPI genes locally at 4 and 8 dpi, and an increase of Tr-KPI1, Tr-KPI2, and Tr-KPI5 at 8 dpi systemically was observed in response to infection with the CCN. Challenge of a resistant (R) genotype and a susceptible (S) genotype of white clover with the CCN revealed a significant increase in transcript abundance of all four Tr-KPI genes locally in the R genotype, while an increase in abundance of only Tr-KPI1, Tr-KPI2, and Tr-KPI5 was observed in the S genotype, and only at 4 dpi. The transcript abundance of a member of the1-AMINOCYCLOPROPANE-1-CARBOXYLATE (ACC) SYNTHASE gene family from white clover (Tr-ACS1) was significantly down-regulated locally in response to CRKN infection at 4 and 8 dpi and at 4 dpi, systemically, while abundance increased locally and systemically at 8 dpi in response to CCN challenge. Conversely, the abundance of the jasmonic acid (JA) signalling gene, CORONATINE-INSENSITIVE PROTEIN 1 from white clover (Tr-COI1) increased significantly at 8 dpi locally in response to CRKN infection, but decreased at 8 dpi in response to CCN infection. The significance of this differential regulation of transcription is discussed with respect to differences in infection strategy of the two nematode species.

Skeletal muscle ACC2 S212 phosphorylation is not required for the control of fatty acid oxidation during exercise.

PubMed

O'Neill, Hayley M; Lally, James S; Galic, Sandra; Pulinilkunnil, Thomas; Ford, Rebecca J; Dyck, Jason R B; van Denderen, Bryce J; Kemp, Bruce E; Steinberg, Gregory R

2015-07-01

During submaximal exercise fatty acids are a predominant energy source for muscle contractions. An important regulator of fatty acid oxidation is acetyl-CoA carboxylase (ACC), which exists as two isoforms (ACC1 and ACC2) with ACC2 predominating in skeletal muscle. Both ACC isoforms regulate malonyl-CoA production, an allosteric inhibitor of carnitine palmitoyltransferase 1 (CPT-1); the primary enzyme controlling fatty acyl-CoA flux into mitochondria for oxidation. AMP-activated protein kinase (AMPK) is a sensor of cellular energy status that is activated during exercise or by pharmacological agents such as metformin and AICAR. In resting muscle the activation of AMPK with AICAR leads to increased phosphorylation of ACC (S79 on ACC1 and S221 on ACC2), which reduces ACC activity and malonyl-CoA; effects associated with increased fatty acid oxidation. However, whether this pathway is vital for regulating skeletal muscle fatty acid oxidation during conditions of increased metabolic flux such as exercise/muscle contractions remains unknown. To examine this we characterized mice lacking AMPK phosphorylation sites on ACC2 (S212 in mice/S221 in humans-ACC2-knock-in [ACC2-KI]) or both ACC1 (S79) and ACC2 (S212) (ACC double knock-in [ACCD-KI]) during submaximal treadmill exercise and/or ex vivo muscle contractions. We find that surprisingly, ACC2-KI mice had normal exercise capacity and whole-body fatty acid oxidation during treadmill running despite elevated muscle ACC2 activity and malonyl-CoA. Similar results were observed in ACCD-KI mice. Fatty acid oxidation was also maintained in muscles from ACC2-KI mice contracted ex vivo. These findings indicate that pathways independent of ACC phosphorylation are important for regulating skeletal muscle fatty acid oxidation during exercise/muscle contractions. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Assessment of Culturable Tea Rhizobacteria Isolated from Tea Estates of Assam, India for Growth Promotion in Commercial Tea Cultivars

PubMed Central

Dutta, Jintu; Handique, Pratap J.; Thakur, Debajit

2015-01-01

In the present study, 217 rhizobacterial isolates were obtained from six different tea estates of Assam, India and subjected to preliminary in vitro plant growth promotion (PGP) screening for indole acetic acid (IAA) production, phosphate solubilization, siderophore production and ammonia production. Fifty isolates showed all the PGP traits and five isolates did not exhibit any PGP traits. These 50 potential isolates were further analyzed for quantitative estimation of the PGP traits along with the aminocyclopropane-1-carboxylate (ACC) deaminase, protease and cellulose production. After several rounds of screening, four rhizobacteria were selected based on their maximum ability to produce in vitro PGP traits and their partial 16S rRNA gene sequence analysis revealed that they belong to Enterobacter lignolyticus strain TG1, Burkholderia sp. stain TT6, Bacillus pseudomycoides strain SN29 and Pseudomonas aeruginosa strain KH45. To evaluate the efficacy of these four rhizobacteria as plant growth promoters, three different commercially important tea clones TV1, TV19, and TV20 plants were inoculated with these rhizobacteria in greenhouse condition and compared to the uninoculated control plants. Though, all the rhizobacterial treatments showed an increase in plant growth compared to control but the multivariate PCA analysis confirmed more growth promotion by TG1 and SN29 strains than the other treatments in all three clones. To validate this result, the fold change analysis was performed and it revealed that the tea clone TV19 plants inoculated with the E. lignolyticus strain TG1 showed maximum root biomass production with an increase in 4.3-fold, shoot biomass with increase in 3.1-fold, root length by 2.2-fold and shoot length by 1.6-fold. Moreover, two way ANOVA analysis also revealed that rhizobacterial treatment in different tea clones showed the significant increase (P < 0.05) in growth promotion compared to the control. Thus, this study indicates that the potential of these indigenous plant growth promoting rhizobacteria isolates to use as microbial inoculation or biofertilizer for growth promotion of tea crops. PMID:26617590

MK-801, but not drugs acting at strychnine-insensitive glycine receptors, attenuate methamphetamine nigrostriatal toxicity.

PubMed

Layer, R T; Bland, L R; Skolnick, P

1993-10-15

Repeated administration of methamphetamine (METH) results in damage to nigrostriatal dopaminergic neurons. Both competitive N-methyl-D-aspartate (NMDA) receptor antagonists and use-dependent cation channel blockers attenuate METH-induced damage. The objectives of the present study were to examine whether comparable reductions in METH-induced damage could be obtained by compounds acting at strychnine-insensitive glycine receptors on the NMDA receptor complex. Four injections of METH (5 mg/kg i.p.) resulted in a approximately 70.9% depletion of striatal dopamine (DA) and approximately 62.7% depletion of dihydroxyphenylacetic acid (DOPAC) content, respectively. A significant protection against METH-induced DA and DOPAC depletion was afforded by the use-dependent channel blocker, MK-801. The competitive glycine antagonist 7-chlorokynurenic acid (7-Cl-KA), the low efficacy glycine partial agonist (+)-3-amino-1-hydroxy-2-pyrrolidone ((+)-HA-966), and the high efficacy partial glycine agonist 1-aminocyclopropane-carboxylic acid (ACPC) were ineffective against METH-induced toxicity despite their abilities to attenuate glutamate-induced neurotoxicity under both in vivo and in vitro conditions. These results indicate that glycinergic ligands do not possess the same broad neuroprotective spectrum as other classes of NMDA antagonists.

Determination and stereochemistry of proteinogenic and non-proteinogenic amino acids in Saudi Arabian date fruits.

PubMed

Ali, Hatem Salama Mohamed; Alhaj, Omar Amin; Al-Khalifa, Abdulrahman Saleh; Brückner, Hans

2014-09-01

Whereas an abundance of literature is available on the occurrence of common proteinogenic amino acids (AAs) in edible fruits of the date palm (Phoenix dactylifera L.), recent reports on non-proteinogenic (non-coded) AAs and amino components are scarce. With emphasis on these components we have analyzed total hydrolysates of twelve cultivars of date fruits using automated ion-exchange chromatography, HPLC employing a fluorescent aminoquinolyl label, and GC-MS of total hydrolysates using the chiral stationary phases Chirasil(®)-L-Val and Lipodex(®) E. Besides common proteinogenic AAs, relatively large amounts of the following non-proteinogenic amino acids were detected: (2S,5R)-5-hydroxypipecolic acid (1.4-4.0 g/kg dry matter, DM), 1-aminocyclopropane-1-carboxylic acid (1.3-2.6 g/kg DM), γ-amino-n-butyric acid (0.5-1.2 g/kg DM), (2S,4R)-4-hydroxyproline (130-230 mg/kg DM), L-pipecolic acid (40-140 mg/kg DM), and 2-aminoethanol (40-160 mg/kg DM) as well as low or trace amounts (<70 mg/kg DM) of L-ornithine, 5-hydroxylysine, β-alanine, and in some samples (<20 mg/kg DM) of (S)-β-aminoisobutyric acid and (<10 mg/kg DM) L-allo-isoleucine. In one date fruit, traces of α-aminoadipic acid could be determined. Enantiomeric analysis of 6 M DCl/D2O hydrolysates of AAs using chiral capillary gas chromatography-mass spectrometry revealed the presence of very low amounts of D-Ala, D-Asp, D-Glu, D-Ser and D-Phe (1.2-0.4%, relative to the corresponding L-enantiomers), besides traces (0.2-1%) of other D-AAs. The possible relevance of non-proteinogenic amino acids in date fruits is briefly addressed.

Role of the Tomato Non-Ripening Mutation in Regulating Fruit Quality Elucidated Using iTRAQ Protein Profile Analysis

PubMed Central

Yuan, Xin-Yu; Wang, Rui-Heng; Zhao, Xiao-Dan; Luo, Yun-Bo; Fu, Da-Qi

2016-01-01

Natural mutants of the Non-ripening (Nor) gene repress the normal ripening of tomato fruit. The molecular mechanism of fruit ripening regulation by the Nor gene is unclear. To elucidate how the Nor gene can affect ripening and fruit quality at the protein level, we used the fruits of Nor mutants and wild-type Ailsa Craig (AC) to perform iTRAQ (isobaric tags for relative and absolute quantitation) analysis. The Nor mutation altered tomato fruit ripening and affected quality in various respects, including ethylene biosynthesis by down-regulating the abundance of 1-aminocyclopropane-1-carboxylic acid oxidase (ACO), pigment biosynthesis by repressing phytoene synthase 1 (PSY1), ζ-carotene isomerase (Z-ISO), chalcone synthase 1 (CHS1) and other proteins, enhancing fruit firmness by increasing the abundance of cellulose synthase protein, while reducing those of polygalacturonase 2 (PG2) and pectate lyase (PL), altering biosynthesis of nutrients such as carbohydrates, amino acids, and anthocyanins. Conversely, Nor mutation also enhanced the fruit’s resistance to some pathogens by up-regulating the expression of several genes associated with stress and defense. Therefore, the Nor gene is involved in the regulation of fruit ripening and quality. It is useful in the future as a means to improve fruit quality in tomato. PMID:27732677

Bacillus: A Biological Tool for Crop Improvement through Bio-Molecular Changes in Adverse Environments

PubMed Central

Radhakrishnan, Ramalingam; Hashem, Abeer; Abd_Allah, Elsayed F.

2017-01-01

Crop productivity is affected by environmental and genetic factors. Microbes that are beneficial to plants are used to enhance the crop yield and are alternatives to chemical fertilizers and pesticides. Pseudomonas and Bacillus species are the predominant plant growth-promoting bacteria. The spore-forming ability of Bacillus is distinguished from that of Pseudomonas. Members of this genus also survive for a long time under unfavorable environmental conditions. Bacillus spp. secrete several metabolites that trigger plant growth and prevent pathogen infection. Limited studies have been conducted to understand the physiological changes that occur in crops in response to Bacillus spp. to provide protection against adverse environmental conditions. This review describes the current understanding of Bacillus-induced physiological changes in plants as an adaptation to abiotic and biotic stresses. During water scarcity, salinity and heavy metal accumulate in soil, Bacillus spp. produce exopolysaccharides and siderophores, which prevent the movement of toxic ions and adjust the ionic balance and water transport in plant tissues while controlling the pathogenic microbial population. In addition, the synthesis of indole-3-acetic acid, gibberellic acid and1-aminocyclopropane-1-carboxylate (ACC) deaminase by Bacillus regulates the intracellular phytohormone metabolism and increases plant stress tolerance. Cell-wall-degrading substances, such as chitosanase, protease, cellulase, glucanase, lipopeptides and hydrogen cyanide from Bacillus spp. damage the pathogenic bacteria, fungi, nematodes, viruses and pests to control their populations in plants and agricultural lands. The normal plant metabolism is affected by unfavorable environmental stimuli, which suppress crop growth and yield. Abiotic and biotic stress factors that have detrimental effects on crops are mitigated by Bacillus-induced physiological changes, including the regulation of water transport, nutrient up-take and the activation of the antioxidant and defense systems. Bacillus association stimulates plant immunity against stresses by altering stress-responsive genes, proteins, phytohormones and related metabolites. This review describes the beneficial effect of Bacillus spp. on crop plants, which improves plant productivity under unfavorable climatic conditions, and the current understanding of the mitigation mechanism of Bacillus spp. in stress-tolerant and/or stress-resistant plants. PMID:28932199

Bacillus: A Biological Tool for Crop Improvement through Bio-Molecular Changes in Adverse Environments.

PubMed

Radhakrishnan, Ramalingam; Hashem, Abeer; Abd Allah, Elsayed F

2017-01-01

Crop productivity is affected by environmental and genetic factors. Microbes that are beneficial to plants are used to enhance the crop yield and are alternatives to chemical fertilizers and pesticides. Pseudomonas and Bacillus species are the predominant plant growth-promoting bacteria. The spore-forming ability of Bacillus is distinguished from that of Pseudomonas . Members of this genus also survive for a long time under unfavorable environmental conditions. Bacillus spp. secrete several metabolites that trigger plant growth and prevent pathogen infection. Limited studies have been conducted to understand the physiological changes that occur in crops in response to Bacillus spp. to provide protection against adverse environmental conditions. This review describes the current understanding of Bacillus -induced physiological changes in plants as an adaptation to abiotic and biotic stresses. During water scarcity, salinity and heavy metal accumulate in soil, Bacillus spp. produce exopolysaccharides and siderophores, which prevent the movement of toxic ions and adjust the ionic balance and water transport in plant tissues while controlling the pathogenic microbial population. In addition, the synthesis of indole-3-acetic acid, gibberellic acid and1-aminocyclopropane-1-carboxylate (ACC) deaminase by Bacillus regulates the intracellular phytohormone metabolism and increases plant stress tolerance. Cell-wall-degrading substances, such as chitosanase, protease, cellulase, glucanase, lipopeptides and hydrogen cyanide from Bacillus spp. damage the pathogenic bacteria, fungi, nematodes, viruses and pests to control their populations in plants and agricultural lands. The normal plant metabolism is affected by unfavorable environmental stimuli, which suppress crop growth and yield. Abiotic and biotic stress factors that have detrimental effects on crops are mitigated by Bacillus -induced physiological changes, including the regulation of water transport, nutrient up-take and the activation of the antioxidant and defense systems. Bacillus association stimulates plant immunity against stresses by altering stress-responsive genes, proteins, phytohormones and related metabolites. This review describes the beneficial effect of Bacillus spp. on crop plants, which improves plant productivity under unfavorable climatic conditions, and the current understanding of the mitigation mechanism of Bacillus spp. in stress-tolerant and/or stress-resistant plants.

ACCERBATIN, a small molecule at the intersection of auxin and reactive oxygen species homeostasis with herbicidal properties.

PubMed

Hu, Yuming; Depaepe, Thomas; Smet, Dajo; Hoyerova, Klara; Klíma, Petr; Cuypers, Ann; Cutler, Sean; Buyst, Dieter; Morreel, Kris; Boerjan, Wout; Martins, José; Petrášek, Jan; Vandenbussche, Filip; Van Der Straeten, Dominique

2017-07-10

The volatile two-carbon hormone ethylene acts in concert with an array of signals to affect etiolated seedling development. From a chemical screen, we isolated a quinoline carboxamide designated ACCERBATIN (AEX) that exacerbates the 1-aminocyclopropane-1-carboxylic acid-induced triple response, typical for ethylene-treated seedlings in darkness. Phenotypic analyses revealed distinct AEX effects including inhibition of root hair development and shortening of the root meristem. Mutant analysis and reporter studies further suggested that AEX most probably acts in parallel to ethylene signaling. We demonstrated that AEX functions at the intersection of auxin metabolism and reactive oxygen species (ROS) homeostasis. AEX inhibited auxin efflux in BY-2 cells and promoted indole-3-acetic acid (IAA) oxidation in the shoot apical meristem and cotyledons of etiolated seedlings. Gene expression studies and superoxide/hydrogen peroxide staining further revealed that the disrupted auxin homeostasis was accompanied by oxidative stress. Interestingly, in light conditions, AEX exhibited properties reminiscent of the quinoline carboxylate-type auxin-like herbicides. We propose that AEX interferes with auxin transport from its major biosynthesis sites, either as a direct consequence of poor basipetal transport from the shoot meristematic region, or indirectly, through excessive IAA oxidation and ROS accumulation. Further investigation of AEX can provide new insights into the mechanisms connecting auxin and ROS homeostasis in plant development and provide useful tools to study auxin-type herbicides. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Evaluation of Varying Biochars as Carrier Materials for Bacterial Soil Inoculants

NASA Astrophysics Data System (ADS)

Hale, Lauren; Crowley, David

2014-05-01

The incorporation of biochar into agricultural soils for carbon sequestration and improved soil fertility creates an opportunity to simultaneously deliver plant-growth promoting rhizobacteria (PGPR). Many characteristics of biochar materials indicate that these particles could be conducive as inoculum carriers. This could provide a value-added component for biochar marketing and has an advantage over traditional carrier materials, which can be unsustainable or expensive to produce. Here, we assessed the suitability of 10 biochar types, made from 5 feedstocks at 2 pyrolysis temperatures (300°C and 600°C), to serve as carriers for 2 model PGPR strains, Enterobacter cloacae UW5 and Pseudomonas putida UW4. All biochars were characterized based on BET specific surface area, C-N content, pH, EC, and their abilities to adsorb bacterial cells from a liquid inoculum. Further studies incorporated qPCR to quantify the survival of inoculants after introduction into soils via biochar carriers. The biochars that performed well were further assayed for their influence on PGPR traits, 1-aminocyclopropane-1-carboxylate (ACC) deaminase and auxin production. Peat and vermiculite served as traditional carrier materials to which we compared the biochars. Our findings indicated that biochars varied in their interactions with our model PGPR strains. Based on our analysis several biochar types were able to serve as carriers which were as good, if not better than, the traditional carrier materials. Future work should seek to assess shelf life and varying inoculation methods for the biochar-inoculant complexes.

Phytoextraction of heavy metal polluted soils using Sedum plumbizincicola inoculated with metal mobilizing Phyllobacterium myrsinacearum RC6b.

PubMed

Ma, Ying; Rajkumar, Mani; Luo, Yongming; Freitas, Helena

2013-10-01

The aim of this study was to investigate the effects of metal mobilizing plant-growth beneficial bacterium Phyllobacterium myrsinacearum RC6b on plant growth and Cd, Zn and Pb uptake by Sedum plumbizincicola under laboratory conditions. Among a collection of metal-resistant bacteria, P. myrsinacearum RC6b was specifically chosen as a most favorable metal mobilizer based on its capability of mobilizing high concentrations of Cd, Zn and Pb in soils. P. myrsinacearum RC6b exhibited a high degree of resistance to Cd (350 mg L(-1)), Zn (1000 mg L(-1)) and Pb (1200 mg L(-1)). Furthermore, P. myrsinacearum RC6b showed multiple plant growth beneficial features including the production of 1-aminocyclopropane-1-carboxylic acid deaminase, indole-3-acetic acid, siderophore and solubilization of insoluble phosphate. Inoculation of P. myrsinacearum RC6b significantly increased S. plumbizincicola growth and organ metal concentrations except Pb, which concentration was lower in root and stem of inoculated plants. The results suggest that the metal mobilizing P. myrsinacearum RC6b could be used as an effective inoculant for the improvement of phytoremediation in multi-metal polluted soils. Copyright © 2013 Elsevier Ltd. All rights reserved.

Involvement of ethylene and polyamines biosynthesis and abdominal phloem tissues characters of wheat caryopsis during grain filling under stress conditions

PubMed Central

Yang, Weibing; Li, Yanxia; Yin, Yanping; Qin, Zhilie; Zheng, Mengjing; Chen, Jin; Luo, Yongli; Pang, Dangwei; Jiang, Wenwen; Li, Yong; Wang, Zhenlin

2017-01-01

Severe water deficit (SD) severely limited the photo-assimilate supply during the grain-filling stages. Although the ethylene and polyamines (PAs) have been identified as important signaling molecules involved in stress tolerance, it is yet unclear how 1-Aminocylopropane-1-carboxylic acid (ACC) and PA biosynthesis involving wheat abdominal phloem characters mitigate SD-induced filling inhibition. The results obtained indicated that the SD down-regulated the TaSUT1 expression and decreased the activities of sucrose synthase (SuSase, EC2.4.1.13), ADP glucose pyrophosphorylase (AGPase, EC2.7.7.27), soluble starch synthase (SSSase, EC2.4.1.21), then substantially limited grain filling. As a result, increased ACC and putrescine (Put) concentrations and their biosynthesis-related gene expression reduced spermidine (Spd) biosynthesis under SD condition. And, the ACC and PA biosynthesis in inferior grains was more sensitive to SD than that in superior grains. Intermediary cells (ICs) of caryopsis emerged prematurely under SD to compensate for the weakened photo-assimilate transport functions of sieve elements (SEs). Finally, plasmolysis and nuclear chromatin condensation of phloem parenchyma cells (PPC) and membrane degradation of SEs, as well as the decreased ATPase activity on plasma membranes of ICs and PPC at the later filling stage under SD were responsible for the considerably decreased weight of inferior grains. PMID:28383077

Indole-3-Butyric Acid Induces Ectopic Formation of Metaxylem in the Hypocotyl of Arabidopsis thaliana without Conversion into Indole-3-Acetic Acid and with a Positive Interaction with Ethylene.

PubMed

Fattorini, Laura; Della Rovere, Federica; Andreini, Eleonora; Ronzan, Marilena; Falasca, Giuseppina; Altamura, Maria Maddalena

2017-11-21

The role of the auxins indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) and of the auxin-interacting phytohormone ethylene, on the ectopic formation of primary xylem (xylogenesis in planta) is still little known. In particular, auxin/ethylene-target tissue(s), modality of the xylary process (trans-differentiation vs. de novo formation), and the kind of ectopic elements formed (metaxylem vs. protoxylem) are currently unknown. It is also unclear whether IBA may act on the process independently of conversion into IAA. To investigate these topics, histological analyses were carried out in the hypocotyls of Arabidopsis wild type seedlings and ech2ibr10 and ein3eil1 mutants, which are blocked in IBA-to-IAA conversion and ethylene signalling, respectively. The seedlings were grown under darkness with either IAA or IBA, combined or not with the ethylene precursor 1-aminocyclopropane-1-carboxylic acid. Adventitious root formation was also investigated because this process may compete with xylogenesis. Our results show that ectopic formation of protoxylem and metaxylem occurred as an indirect process starting from the pericycle periclinal derivatives of the hypocotyl basal part. IAA favoured protoxylem formation, whereas IBA induced ectopic metaxylem with ethylene cooperation through the EIN3EIL1 network. Ectopic metaxylem differentiation occurred independently of IBA-to-IAA conversion as mediated by ECH2 and IBR10, and in the place of IBA-induced adventitious root formation.

The dynamic organization of fungal acetyl-CoA carboxylase

NASA Astrophysics Data System (ADS)

Hunkeler, Moritz; Stuttfeld, Edward; Hagmann, Anna; Imseng, Stefan; Maier, Timm

2016-04-01

Acetyl-CoA carboxylases (ACCs) catalyse the committed step in fatty-acid biosynthesis: the ATP-dependent carboxylation of acetyl-CoA to malonyl-CoA. They are important regulatory hubs for metabolic control and relevant drug targets for the treatment of the metabolic syndrome and cancer. Eukaryotic ACCs are single-chain multienzymes characterized by a large, non-catalytic central domain (CD), whose role in ACC regulation remains poorly characterized. Here we report the crystal structure of the yeast ACC CD, revealing a unique four-domain organization. A regulatory loop, which is phosphorylated at the key functional phosphorylation site of fungal ACC, wedges into a crevice between two domains of CD. Combining the yeast CD structure with intermediate and low-resolution data of larger fragments up to intact ACCs provides a comprehensive characterization of the dynamic fungal ACC architecture. In contrast to related carboxylases, large-scale conformational changes are required for substrate turnover, and are mediated by the CD under phosphorylation control.

Novel Three-Component Phenazine-1-Carboxylic Acid 1,2-Dioxygenase in Sphingomonas wittichii DP58

PubMed Central

Zhao, Qiang; Wang, Wei; Huang, Xian-Qing; Zhang, Xue-Hong

2017-01-01

ABSTRACT Phenazine-1-carboxylic acid, the main component of shenqinmycin, is widely used in southern China for the prevention of rice sheath blight. However, the fate of phenazine-1-carboxylic acid in soil remains uncertain. Sphingomonas wittichii DP58 can use phenazine-1-carboxylic acid as its sole carbon and nitrogen sources for growth. In this study, dioxygenase-encoding genes, pcaA1A2, were found using transcriptome analysis to be highly upregulated upon phenazine-1-carboxylic acid biodegradation. PcaA1 shares 68% amino acid sequence identity with the large oxygenase subunit of anthranilate 1,2-dioxygenase from Rhodococcus maanshanensis DSM 44675. The dioxygenase was coexpressed in Escherichia coli with its adjacent reductase-encoding gene, pcaA3, and ferredoxin-encoding gene, pcaA4, and showed phenazine-1-carboxylic acid consumption. The dioxygenase-, ferredoxin-, and reductase-encoding genes were expressed in Pseudomonas putida KT2440 or E. coli BL21, and the three recombinant proteins were purified. A phenazine-1-carboxylic acid conversion capability occurred in vitro only when all three components were present. However, P. putida KT2440 transformed with pcaA1A2 obtained phenazine-1-carboxylic acid degradation ability, suggesting that phenazine-1-carboxylic acid 1,2-dioxygenase has low specificities for its ferredoxin and reductase. This was verified by replacing PcaA3 with RedA2 in the in vitro enzyme assay. High-performance liquid chromatography–mass spectrometry (HPLC-MS) and nuclear magnetic resonance (NMR) analysis showed that phenazine-1-carboxylic acid was converted to 1,2-dihydroxyphenazine through decarboxylation and hydroxylation, indicating that PcaA1A2A3A4 constitutes the initial phenazine-1-carboxylic acid 1,2-dioxygenase. This study fills a gap in our understanding of the biodegradation of phenazine-1-carboxylic acid and illustrates a new dioxygenase for decarboxylation. IMPORTANCE Phenazine-1-carboxylic acid is widely used in southern China as a key fungicide to prevent rice sheath blight. However, the degradation characteristics of phenazine-1-carboxylic acid and the environmental consequences of the long-term application are not clear. S. wittichii DP58 can use phenazine-1-carboxylic acid as its sole carbon and nitrogen sources. In this study, a three-component dioxygenase, PcaA1A2A3A4, was determined to be the initial dioxygenase for phenazine-1-carboxylic acid degradation in S. wittichii DP58. Phenazine-1-carboxylic acid was converted to 1,2-dihydroxyphenazine through decarboxylation and hydroxylation. This finding may help us discover the pathway for phenazine-1-carboxylic acid degradation. PMID:28188209

Polyamines Attenuate Ethylene-Mediated Defense Responses to Abrogate Resistance to Botrytis cinerea in Tomato1[C][W][OA

PubMed Central

Nambeesan, Savithri; AbuQamar, Synan; Laluk, Kristin; Mattoo, Autar K.; Mickelbart, Michael V.; Ferruzzi, Mario G.; Mengiste, Tesfaye; Handa, Avtar K.

2012-01-01

Transgenic tomato (Solanum lycopersicum) lines overexpressing yeast spermidine synthase (ySpdSyn), an enzyme involved in polyamine (PA) biosynthesis, were developed. These transgenic lines accumulate higher levels of spermidine (Spd) than the wild-type plants and were examined for responses to the fungal necrotrophs Botrytis cinerea and Alternaria solani, bacterial pathogen Pseudomonas syringae pv tomato DC3000, and larvae of the chewing insect tobacco hornworm (Manduca sexta). The Spd-accumulating transgenic tomato lines were more susceptible to B. cinerea than the wild-type plants; however, responses to A. solani, P. syringae, or M. sexta were similar to the wild-type plants. Exogenous application of ethylene precursors, S-adenosyl-Met and 1-aminocyclopropane-1-carboxylic acid, or PA biosynthesis inhibitors reversed the response of the transgenic plants to B. cinerea. The increased susceptibility of the ySpdSyn transgenic tomato to B. cinerea was associated with down-regulation of gene transcripts involved in ethylene biosynthesis and signaling. These data suggest that PA-mediated susceptibility to B. cinerea is linked to interference with the functions of ethylene in plant defense. PMID:22128140

Leguminosae native nodulating bacteria from a gold mine As-contaminated soil: Multi-resistance to trace elements, and possible role in plant growth and mineral nutrition.

PubMed

Rangel, Wesley de M; de Oliveira Longatti, Silvia M; Ferreira, Paulo A A; Bonaldi, Daiane S; Guimarães, Amanda A; Thijs, Sofie; Weyens, Nele; Vangronsveld, Jaco; Moreira, Fatima M S

2017-10-03

Efficient N 2 -fixing Leguminosae nodulating bacteria resistant to As may facilitate plant growth on As-contaminated sites. In order to identify bacteria holding these features, 24 strains were isolated from nodules of the trap species Crotalaria spectabilis (12) and Stizolobium aterrimum (12) growing on an As-contaminated gold mine site. 16S rRNA gene sequencing revealed that most of the strains belonged to the group of α-Proteobacteria, being representatives of the genera Bradyrhizobium, Rhizobium, Inquilinus, Labrys, Bosea, Starkeya, and Methylobacterium. Strains of the first four genera showed symbiotic efficiency with their original host, and demonstrated in vitro specific plant-growth-promoting (PGP) traits (production of organic acids, indole-3-acetic-acid and siderophores, 1-aminocyclopropane-1-carboxylate deaminase activity, and Ca 3 (PO 4 ) 2 solubilization), and increased resistance to As, Zn, and Cd. In addition, these strains and some type and reference rhizobia strains exhibited a wide resistance spectrum to β-lactam antibiotics. Both intrinsic PGP abilities and multi-element resistance of rhizobia are promising for exploiting the symbiosis with different legume plants on trace-element-contaminated soils.

Draft genome sequences of bacteria isolated from the Deschampsia antarctica phyllosphere.

PubMed

Cid, Fernanda P; Maruyama, Fumito; Murase, Kazunori; Graether, Steffen P; Larama, Giovanni; Bravo, Leon A; Jorquera, Milko A

2018-05-01

Genome analyses are being used to characterize plant growth-promoting (PGP) bacteria living in different plant compartiments. In this context, we have recently isolated bacteria from the phyllosphere of an Antarctic plant (Deschampsia antarctica) showing ice recrystallization inhibition (IRI), an activity related to the presence of antifreeze proteins (AFPs). In this study, the draft genomes of six phyllospheric bacteria showing IRI activity were sequenced and annotated according to their functional gene categories. Genome sizes ranged from 5.6 to 6.3 Mbp, and based on sequence analysis of the 16S rRNA genes, five strains were identified as Pseudomonas and one as Janthinobacterium. Interestingly, most strains showed genes associated with PGP traits, such as nutrient uptake (ammonia assimilation, nitrogen fixing, phosphatases, and organic acid production), bioactive metabolites (indole acetic acid and 1-aminocyclopropane-1-carboxylate deaminase), and antimicrobial compounds (hydrogen cyanide and pyoverdine). In relation with IRI activity, a search of putative AFPs using current bioinformatic tools was also carried out. Despite that genes associated with reported AFPs were not found in these genomes, genes connected to ice-nucleation proteins (InaA) were found in all Pseudomonas strains, but not in the Janthinobacterium strain.

Potential of Rice Stubble as a Reservoir of Bradyrhizobial Inoculum in Rice-Legume Crop Rotation

PubMed Central

Piromyou, Pongdet; Greetatorn, Teerana; Teamtisong, Kamonluck; Tittabutr, Panlada; Boonkerd, Nantakorn

2017-01-01

ABSTRACT Bradyrhizobium encompasses a variety of bacteria that can live in symbiotic and endophytic associations with leguminous and nonleguminous plants, such as rice. Therefore, it can be expected that rice endophytic bradyrhizobia can be applied in the rice-legume crop rotation system. Some endophytic bradyrhizobial strains were isolated from rice (Oryza sativa L.) tissues. The rice biomass could be enhanced when supplementing bradyrhizobial strain inoculation with KNO3, NH4NO3, or urea, especially in Bradyrhizobium sp. strain SUTN9-2. In contrast, the strains which suppressed rice growth were photosynthetic bradyrhizobia and were found to produce nitric oxide (NO) in the rice root. The expression of genes involved in NO production was conducted using a quantitative reverse transcription-PCR (qRT-PCR) technique. The nirK gene expression level in Bradyrhizobium sp. strain SUT-PR48 with nitrate was higher than that of the norB gene. In contrast, the inoculation of SUTN9-2 resulted in a lower expression of the nirK gene than that of the norB gene. These results suggest that SUT-PR48 may accumulate NO more than SUTN9-2 does. Furthermore, the nifH expression of SUTN9-2 was induced in treatment without nitrogen supplementation in an endophytic association with rice. The indole-3-acetic acid (IAA) and 1-amino-cyclopropane-1-carboxylic acid (ACC) deaminase produced in planta by SUTN9-2 were also detected. Enumeration of rice endophytic bradyrhizobia from rice tissues revealed that SUTN9-2 persisted in rice tissues until rice-harvesting season. The mung bean (Vigna radiata) can be nodulated after rice stubbles were decomposed. Therefore, it is possible that rice stubbles can be used as an inoculum in the rice-legume crop rotation system under both low- and high-organic-matter soil conditions. IMPORTANCE This study shows that some rice endophytic bradyrhizobia could produce IAA and ACC deaminase and have a nitrogen fixation ability during symbiosis inside rice tissues. These characteristics may play an important role in rice growth promotion by endophytic bradyrhizobia. However, the NO-producing strains should be of concern due to a possible deleterious effect of NO on rice growth. In addition, this study reports the application of endophytic bradyrhizobia in rice stubbles, and the rice stubbles were used directly as an inoculum for a leguminous plant (mung bean). The degradation of rice stubbles leads to an increased number of SUTN9-2 in the soil and may result in increased mung bean nodulation. Therefore, the persistence of endophytic bradyrhizobia in rice tissues can be developed to use rice stubbles as an inoculum for mung bean in a rice-legume crop rotation system. PMID:28916558

Potential of Rice Stubble as a Reservoir of Bradyrhizobial Inoculum in Rice-Legume Crop Rotation.

PubMed

Piromyou, Pongdet; Greetatorn, Teerana; Teamtisong, Kamonluck; Tittabutr, Panlada; Boonkerd, Nantakorn; Teaumroong, Neung

2017-11-15

Bradyrhizobium encompasses a variety of bacteria that can live in symbiotic and endophytic associations with leguminous and nonleguminous plants, such as rice. Therefore, it can be expected that rice endophytic bradyrhizobia can be applied in the rice-legume crop rotation system. Some endophytic bradyrhizobial strains were isolated from rice ( Oryza sativa L.) tissues. The rice biomass could be enhanced when supplementing bradyrhizobial strain inoculation with KNO 3 , NH 4 NO 3 , or urea, especially in Bradyrhizobium sp. strain SUTN9-2. In contrast, the strains which suppressed rice growth were photosynthetic bradyrhizobia and were found to produce nitric oxide (NO) in the rice root. The expression of genes involved in NO production was conducted using a quantitative reverse transcription-PCR (qRT-PCR) technique. The nirK gene expression level in Bradyrhizobium sp. strain SUT-PR48 with nitrate was higher than that of the norB gene. In contrast, the inoculation of SUTN9-2 resulted in a lower expression of the nirK gene than that of the norB gene. These results suggest that SUT-PR48 may accumulate NO more than SUTN9-2 does. Furthermore, the nifH expression of SUTN9-2 was induced in treatment without nitrogen supplementation in an endophytic association with rice. The indole-3-acetic acid (IAA) and 1-amino-cyclopropane-1-carboxylic acid (ACC) deaminase produced in planta by SUTN9-2 were also detected. Enumeration of rice endophytic bradyrhizobia from rice tissues revealed that SUTN9-2 persisted in rice tissues until rice-harvesting season. The mung bean ( Vigna radiata ) can be nodulated after rice stubbles were decomposed. Therefore, it is possible that rice stubbles can be used as an inoculum in the rice-legume crop rotation system under both low- and high-organic-matter soil conditions. IMPORTANCE This study shows that some rice endophytic bradyrhizobia could produce IAA and ACC deaminase and have a nitrogen fixation ability during symbiosis inside rice tissues. These characteristics may play an important role in rice growth promotion by endophytic bradyrhizobia. However, the NO-producing strains should be of concern due to a possible deleterious effect of NO on rice growth. In addition, this study reports the application of endophytic bradyrhizobia in rice stubbles, and the rice stubbles were used directly as an inoculum for a leguminous plant (mung bean). The degradation of rice stubbles leads to an increased number of SUTN9-2 in the soil and may result in increased mung bean nodulation. Therefore, the persistence of endophytic bradyrhizobia in rice tissues can be developed to use rice stubbles as an inoculum for mung bean in a rice-legume crop rotation system. Copyright © 2017 American Society for Microbiology.

The role of ethylene in the development of constant-light injury of potato and tomato

NASA Technical Reports Server (NTRS)

Cushman, K. E.; Tibbitts, T. W.

1998-01-01

The role of ethylene in the development of constant-light injury of potato (Solanum tuberosum L.) and tomato (Lycopersicon esculentum Mill.) was investigated. In one study, silver thiosulfate (STS) was applied to the foliage of four potato cultivars growing under constant light. Leaf area and shoot dry mass of 'Kennebec' and 'Superior', cultivars normally injured by constant light, were greater (P < 0.05) than those of control plants given foliar applications of distilled water. Examination of STS-treated 'Kennebec' leaflets revealed significantly less injury (necrotic spotting and reduced starch content) than the water-treated controls. 'Norland' and 'Denali', cultivars tolerant of constant light, exhibited no differences in growth between treatments. In a second study, injury (necrotic spotting and reduced starch content) was induced in leaflets of 'Denali' when exposed to spray applications of 0.5 mmol L-1 ethephon or air containing 0.5 to 0.8 microL L-1 ethylene. In a third study, three genotypes of 'Ailsa Craig' tomato were grown under constant light. Leaves of the normal 'Ailsa Craig' exhibited epinasty, reduced chlorophyll concentration, and reduced starch content. Leaves of a mutant 'Ailsa Craig', containing the Never ripe mutation, did not exhibit epinasty but exhibited the same amount of reduced chlorophyll concentration and starch content as normal plants. Leaves of a transgenic 'Ailsa Craig', containing an antisense gene of 1-aminocyclopropane 1-carboxylate (ACC) oxidase, were epinastic, but chlorophyll concentration and starch content were greater than in leaves of normal and mutant plants. These results suggest that transgenic plants were more tolerant of constant light than the other genotypes. Evidence from these studies indicates that ethylene, combined with constant light, has an important role in the development of constant-light injury.

Polyamines and ethylene interact in rice grains in response to soil drying during grain filling.

PubMed

Chen, Tingting; Xu, Yunji; Wang, Jingchao; Wang, Zhiqin; Yang, Jianchang; Zhang, Jianhua

2013-05-01

This study tested the hypothesis that the interaction between polyamines and ethylene may mediate the effects of soil drying on grain filling of rice (Oryza sativa L.). Two rice cultivars were pot grown. Three treatments, well-watered, moderate soil drying (MD), and severe soil drying (SD), were imposed from 8 d post-anthesis until maturity. The endosperm cell division rate, grain-filling rate, and grain weight of earlier flowering superior spikelets showed no significant differences among the three treatments. However, those of the later flowering inferior spikelets were significantly increased under MD and significantly reduced under SD when compared with those which were well watered. The two cultivars showed the same tendencies. MD increased the contents of free spermidine (Spd) and free spermine (Spm), the activities of S-adenosyl-L-methionine decarboxylase and Spd synthase, and expression levels of polyamine synthesis genes, and decreased the ethylene evolution rate, the contents of 1-aminocylopropane-1-carboxylic acid (ACC) and hydrogen peroxide, the activities of ACC synthase, ACC oxidase, and polyamine oxidase, and the expression levels of ethylene synthesis genes in inferior spikelets. SD exhibited the opposite effects. Application of Spd, Spm, or an inhibitor of ethylene synthesis to rice panicles significantly reduced ethylene and ACC levels, but significantly increased Spd and Spm contents, grain-filling rate, and grain weight of inferior spikelets. The results were reversed when ACC or an inhibitor of Spd and Spm synthesis was applied. The results suggest that a potential metabolic interaction between polyamines and ethylene biosynthesis responds to soil drying and mediates the grain filling of inferior spikelets in rice.

Effects of ethrel, 1-MCP and modified atmosphere packaging on the quality of 'Wonderful' pomegranates during cold storage.

PubMed

Valdenegro, Mónika; Huidobro, Camila; Monsalve, Liliam; Bernales, Maricarmen; Fuentes, Lida; Simpson, Ricardo

2018-03-24

Pomegranate (Punica granatum) is a non-climacteric fruit susceptible to chilling injury (CI) at temperatures below 5 °C. To understand the influences of ethylene and modified atmosphere on CI physiological disorders of pomegranate, exogenous ethrel (0.5, 1 and 1.5 µg L -1 ) treatments, 1-methylcyclopropene (1-MCP) (1 µL L -1 ) exposure, packaging in a modified atmosphere (MAP) (XTend™ bags; StePac, São Paulo, Brazil), a MAP/1-MCP combination, and packaging in macro-perforated bags (MPB) were applied. The treated fruits were cold stored (2 ± 1 °C; 85% relative humidity) and sampled during 120 + 3 days at 20 °C. During cold storage, CI symptoms started at 20 days in MPB and at 60 days for all exogenous ethylene treatments, and were delayed to 120 days in MAP, 1-MCP and MAP/1-MCP treatments. MPB and ethylene treatments induced significant electrolyte leakage, oxidative damage, lipid peroxidation, ethylene and CO 2 production, and 1-aminocyclopropane-1-carboxylic acid oxidase activity, without any change in total soluble solids, titratable acidity or skin and aril colours. Conversely, MAP by itself, or in combination with 1-MCP application, effectively delayed CI symptoms. During long-term cold storage of this non-climacteric fruit, ethrel application induced endogenous ethylene biosynthesis, accelerating the appearance of CI symptoms in contrast to the observations made for MAP and 1-MCP treatments. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

Ectopic overexpression of the cell wall invertase gene CIN1 leads to dehydration avoidance in tomato.

PubMed

Albacete, Alfonso; Cantero-Navarro, Elena; Großkinsky, Dominik K; Arias, Cintia L; Balibrea, María Encarnación; Bru, Roque; Fragner, Lena; Ghanem, Michel E; González, María de la Cruz; Hernández, Jose A; Martínez-Andújar, Cristina; van der Graaff, Eric; Weckwerth, Wolfram; Zellnig, Günther; Pérez-Alfocea, Francisco; Roitsch, Thomas

2015-02-01

Drought stress conditions modify source-sink relations, thereby influencing plant growth, adaptive responses, and consequently crop yield. Invertases are key metabolic enzymes regulating sink activity through the hydrolytic cleavage of sucrose into hexose monomers, thus playing a crucial role in plant growth and development. However, the physiological role of invertases during adaptation to abiotic stress conditions is not yet fully understood. Here it is shown that plant adaptation to drought stress can be markedly improved in tomato (Solanum lycopersicum L.) by overexpression of the cell wall invertase (cwInv) gene CIN1 from Chenopodium rubrum. CIN1 overexpression limited stomatal conductance under normal watering regimes, leading to reduced water consumption during the drought period, while photosynthetic activity was maintained. This caused a strong increase in water use efficiency (up to 50%), markedly improving water stress adaptation through an efficient physiological strategy of dehydration avoidance. Drought stress strongly reduced cwInv activity and induced its proteinaceous inhibitor in the leaves of the wild-type plants. However, the CIN1-overexpressing plants registered 3- to 6-fold higher cwInv activity in all analysed conditions. Surprisingly, the enhanced invertase activity did not result in increased hexose concentrations due to the activation of the metabolic carbohydrate fluxes, as reflected by the maintenance of the activity of key enzymes of primary metabolism and increased levels of sugar-phosphate intermediates under water deprivation. The induced sink metabolism in the leaves explained the maintenance of photosynthetic activity, delayed senescence, and increased source activity under drought stress. Moreover, CIN1 plants also presented a better control of production of reactive oxygen species and sustained membrane protection. Those metabolic changes conferred by CIN1 overexpression were accompanied by increases in the concentrations of the senescence-delaying hormone trans-zeatin and decreases in the senescence-inducing ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) in the leaves. Thus, cwInv critically functions at the integration point of metabolic, hormonal, and stress signals, providing a novel strategy to overcome drought-induced limitations to crop yield, without negatively affecting plant fitness under optimal growth conditions. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Root Formation in Ethylene-Insensitive Plants1

PubMed Central

Clark, David G.; Gubrium, Erika K.; Barrett, James E.; Nell, Terril A.; Klee, Harry J.

1999-01-01

Experiments with ethylene-insensitive tomato (Lycopersicon esculentum) and petunia (Petunia × hybrida) plants were conducted to determine if normal or adventitious root formation is affected by ethylene insensitivity. Ethylene-insensitive Never ripe (NR) tomato plants produced more belowground root mass but fewer aboveground adventitious roots than wild-type Pearson plants. Applied auxin (indole-3-butyric acid) increased adventitious root formation on vegetative stem cuttings of wild-type plants but had little or no effect on rooting of NR plants. Reduced adventitious root formation was also observed in ethylene-insensitive transgenic petunia plants. Applied 1-aminocyclopropane-1-carboxylic acid increased adventitious root formation on vegetative stem cuttings from NR and wild-type plants, but NR cuttings produced fewer adventitious roots than wild-type cuttings. These data suggest that the promotive effect of auxin on adventitious rooting is influenced by ethylene responsiveness. Seedling root growth of tomato in response to mechanical impedance was also influenced by ethylene sensitivity. Ninety-six percent of wild-type seedlings germinated and grown on sand for 7 d grew normal roots into the medium, whereas 47% of NR seedlings displayed elongated taproots, shortened hypocotyls, and did not penetrate the medium. These data indicate that ethylene has a critical role in various responses of roots to environmental stimuli. PMID:10482660

Functional reconstitution of the Mycobacterium tuberculosis long-chain acyl-CoA carboxylase from multiple acyl-CoA subunits.

PubMed

Bazet Lyonnet, Bernardo; Diacovich, Lautaro; Gago, Gabriela; Spina, Lucie; Bardou, Fabienne; Lemassu, Anne; Quémard, Annaïk; Gramajo, Hugo

2017-04-01

Mycobacterium tuberculosis produces a large number of structurally diverse lipids that have been implicated in the pathogenicity, persistence and antibiotic resistance of this organism. Most building blocks involved in the biosynthesis of all these lipids are generated by acyl-CoA carboxylases whose subunit composition and physiological roles have not yet been clearly established. Inconclusive data in the literature refer to the exact protein composition and substrate specificity of the enzyme complex that produces the long-chain α-carboxy-acyl-CoAs, which are substrates involved in the last step of condensation mediated by the polyketide synthase 13 to synthesize mature mycolic acids. Here we have successfully reconstituted the long-chain acyl-CoA carboxylase (LCC) complex from its purified components, the α subunit (AccA3), the ε subunit (AccE5) and the two β subunits (AccD4 and AccD5), and demonstrated that the four subunits are essential for its activity. Furthermore, we also showed by substrate competition experiments and the use of a specific inhibitor that the AccD5 subunit's role in the carboxylation of the long acyl-CoAs, as part of the LCC complex, was structural rather than catalytic. Moreover, AccD5 was also able to carboxylate its natural substrates, acetyl-CoA and propionyl-CoA, in the context of the LCC enzyme complex. Thus, the supercomplex formed by these four subunits has the potential to generate the main substrates, malonyl-CoA, methylmalonyl-CoA and α-carboxy-C 24-26 -CoA, used as condensing units for the biosynthesis of all the lipids present in this pathogen. © 2017 Federation of European Biochemical Societies.

Comparison of the A-Cc curve fitting methods in determining maximum ribulose 1.5-bisphosphate carboxylase/oxygenase carboxylation rate, potential light saturated electron transport rate and leaf dark respiration.

PubMed

Miao, Zewei; Xu, Ming; Lathrop, Richard G; Wang, Yufei

2009-02-01

A review of the literature revealed that a variety of methods are currently used for fitting net assimilation of CO2-chloroplastic CO2 concentration (A-Cc) curves, resulting in considerable differences in estimating the A-Cc parameters [including maximum ribulose 1.5-bisphosphate carboxylase/oxygenase (Rubisco) carboxylation rate (Vcmax), potential light saturated electron transport rate (Jmax), leaf dark respiration in the light (Rd), mesophyll conductance (gm) and triose-phosphate utilization (TPU)]. In this paper, we examined the impacts of fitting methods on the estimations of Vcmax, Jmax, TPU, Rd and gm using grid search and non-linear fitting techniques. Our results suggested that the fitting methods significantly affected the predictions of Rubisco-limited (Ac), ribulose 1,5-bisphosphate-limited (Aj) and TPU-limited (Ap) curves and leaf photosynthesis velocities because of the inconsistent estimate of Vcmax, Jmax, TPU, Rd and gm, but they barely influenced the Jmax : Vcmax, Vcmax : Rd and Jmax : TPU ratio. In terms of fitting accuracy, simplicity of fitting procedures and sample size requirement, we recommend to combine grid search and non-linear techniques to directly and simultaneously fit Vcmax, Jmax, TPU, Rd and gm with the whole A-Cc curve in contrast to the conventional method, which fits Vcmax, Rd or gm first and then solves for Vcmax, Jmax and/or TPU with V(cmax), Rd and/or gm held as constants.

Acetyl CoA Carboxylase Inhibition Reduces Hepatic Steatosis but Elevates Plasma Triglycerides in Mice and Humans: A Bedside to Bench Investigation.

PubMed

Kim, Chai-Wan; Addy, Carol; Kusunoki, Jun; Anderson, Norma N; Deja, Stanislaw; Fu, Xiaorong; Burgess, Shawn C; Li, Cai; Ruddy, Marcie; Chakravarthy, Manu; Previs, Steve; Milstein, Stuart; Fitzgerald, Kevin; Kelley, David E; Horton, Jay D

2017-08-01

Inhibiting lipogenesis prevents hepatic steatosis in rodents with insulin resistance. To determine if reducing lipogenesis functions similarly in humans, we developed MK-4074, a liver-specific inhibitor of acetyl-CoA carboxylase (ACC1) and (ACC2), enzymes that produce malonyl-CoA for fatty acid synthesis. MK-4074 administered to subjects with hepatic steatosis for 1 month lowered lipogenesis, increased ketones, and reduced liver triglycerides by 36%. Unexpectedly, MK-4074 increased plasma triglycerides by 200%. To further investigate, mice that lack ACC1 and ACC2 in hepatocytes (ACC dLKO) were generated. Deletion of ACCs decreased polyunsaturated fatty acid (PUFA) concentrations in liver due to reduced malonyl-CoA, which is required for elongation of essential fatty acids. PUFA deficiency induced SREBP-1c, which increased GPAT1 expression and VLDL secretion. PUFA supplementation or siRNA-mediated knockdown of GPAT1 normalized plasma triglycerides. Thus, inhibiting lipogenesis in humans reduced hepatic steatosis, but inhibiting ACC resulted in hypertriglyceridemia due to activation of SREBP-1c and increased VLDL secretion. Copyright © 2017 Elsevier Inc. All rights reserved.

Increased sensitivity to salt stress in tocopherol-deficient Arabidopsis mutants growing in a hydroponic system

PubMed Central

Ellouzi, Hasna; Hamed, Karim Ben; Cela, Jana; Müller, Maren; Abdelly, Chedly; Munné-Bosch, Sergi

2013-01-01

Recent studies suggest that tocopherols could play physiological roles in salt tolerance but the mechanisms are still unknown. In this study, we analyzed changes in growth, mineral and oxidative status in vte1 and vte4 Arabidopsis thaliana mutants exposed to salt stress. vte1 and vte4 mutants lack α-tocopherol, but only the vte1 mutant is additionally deficient in γ-tocopherol. Results showed that a deficiency in vitamin E leads to reduced growth and increased oxidative stress in hydroponically-grown plants. This effect was observed at early stages, not only in rosettes but also in roots. The vte1 mutant was more sensitive to salt-induced oxidative stress than the wild type and the vte4 mutant. Salt sensitivity was associated with (i) high contents of Na+, (ii) reduced efficiency of PSII photochemistry (Fv/Fm ratio) and (iii) more pronounced oxidative stress as indicated by increased hydrogen peroxide and malondialdeyde levels. The vte 4 mutant, which accumulates γ- instead of α-tocopherol showed an intermediate sensitivity to salt stress between the wild type and the vte1 mutant. Contents of abscisic acid, jasmonic acid and the ethylene precursor, 1-aminocyclopropane-1-carboxylic acid were higher in the vte1 mutant than the vte4 mutant and wild type. It is concluded that vitamin E-deficient plants show an increased sensitivity to salt stress both in rosettes and roots, therefore indicating the positive role of tocopherols in stress tolerance, not only by minimizing oxidative stress, but also controlling Na+/K+ homeostasis and hormonal balance. PMID:23299430

Multilayered Regulation of Ethylene Induction Plays a Positive Role in Arabidopsis Resistance against Pseudomonas syringae1[OPEN

PubMed Central

Guan, Rongxia; Su, Jianbin; Meng, Xiangzong; Li, Sen; Liu, Yidong; Xu, Juan; Zhang, Shuqun

2015-01-01

Ethylene, a key phytohormone involved in plant-pathogen interaction, plays a positive role in plant resistance against fungal pathogens. However, its function in plant bacterial resistance remains unclear. Here, we report a detailed analysis of ethylene induction in Arabidopsis (Arabidopsis thaliana) in response to Pseudomonas syringae pv tomato DC3000 (Pst). Ethylene biosynthesis is highly induced in both pathogen/microbe-associated molecular pattern (PAMP)-triggered immunity and effector-triggered immunity (ETI), and the induction is potentiated by salicylic acid (SA) pretreatment. In addition, Pst actively suppresses PAMP-triggered ethylene induction in a type III secretion system-dependent manner. SA potentiation of ethylene induction is dependent mostly on MITOGEN-ACTIVATED PROTEIN KINASE6 (MPK6) and MPK3 and their downstream ACS2 and ACS6, two type I isoforms of 1-aminocyclopropane-1-carboxylic acid synthases (ACSs). ACS7, a type III ACS whose expression is enhanced by SA pretreatment, is also involved. Pst expressing the avrRpt2 effector gene (Pst-avrRpt2), which is capable of triggering ETI, induces a higher level of ethylene production, and the elevated portion is dependent on SALICYLIC ACID INDUCTION DEFICIENT2 and NONEXPRESSER OF PATHOGENESIS-RELATED GENE1, two key players in SA biosynthesis and signaling. High-order ACS mutants with reduced ethylene induction are more susceptible to both Pst and Pst-avrRpt2, demonstrating a positive role of ethylene in plant bacterial resistance mediated by both PAMP-triggered immunity and ETI. PMID:26265775

Tobacco LSU-like protein couples sulphur-deficiency response with ethylene signalling pathway.

PubMed

Moniuszko, Grzegorz; Skoneczny, Marek; Zientara-Rytter, Katarzyna; Wawrzyńska, Anna; Głów, Dawid; Cristescu, Simona M; Harren, Frans J M; Sirko, Agnieszka

2013-11-01

Most genes from the plant-specific family encoding Response to Low Sulphur (LSU)-like proteins are strongly induced in sulphur (S)-deficient conditions. The exact role of these proteins remains unclear; however, some data suggest their importance for plants' adjustment to nutrient deficiency and other environmental stresses. This work established that the regulation of ethylene signalling is a part of plants' response to S deficiency and showed the interaction between UP9C, a tobacco LSU family member, and one of the tobacco isoforms of 1-aminocyclopropane-1-carboxylic acid oxidase (ACO2A). Increase in ethylene level induced by S deficiency does not take place in tobacco plants with UP9C expressed in an antisense orientation. Based on transcriptomics data, this work also demonstrated that the majority of tobacco's response to S deficiency is misregulated in plants expressing UP9C-antisense. A link between response to S deficiency, ethylene sensing, and LSU-like proteins was emphasized by changes in expression of the genes encoding ethylene receptors and F-box proteins specific for the ethylene pathway.

OsBIRH1, a DEAD-box RNA helicase with functions in modulating defence responses against pathogen infection and oxidative stress

PubMed Central

Li, Dayong; Liu, Huizhi; Zhang, Huijuan; Wang, Xiaoe; Song, Fengming

2008-01-01

DEAD-box proteins comprise a large protein family with members from all kingdoms and play important roles in all types of processes in RNA metabolism. In this study, a rice gene OsBIRH1, which encodes a DEAD-box RNA helicase protein, was cloned and characterized. The predicted OsBIRH1 protein contains a DEAD domain and all conserved motifs that are common characteristics of DEAD-box RNA helicases. Recombinant OsBIRH1 protein purified from Escherichia coli was shown to have both RNA-dependent ATPase and ATP-dependent RNA helicase activities in vitro. Expression of OsBIRH1 was activated in rice seedling leaves after treatment with defence-related signal chemicals, for example benzothiadiazole, salicylic acid, l-aminocyclopropane-1-carboxylic acid, and jasmonic acid, and was also up-regulated in an incompatible interaction between a resistant rice genotype and the blast fungus, Magnaporthe grisea. Transgenic Arabidopsis plants that overexpress the OsBIRH1 gene were generated. Disease resistance phenotype assays revealed that the OsBIRH1-overexpressing transgenic plants showed an enhanced disease resistance against Alternaria brassicicola and Pseudomonas syringae pv. tomato DC3000. Meanwhile, defence-related genes, for example PR-1, PR-2, PR-5, and PDF1.2, showed an up-regulated expression in the transgenic plants. Moreover, the OsBIRH1 transgenic Arabidopsis plants also showed increased tolerance to oxidative stress and elevated expression levels of oxidative defence genes, AtApx1, AtApx2, and AtFSD1. The results suggest that OsBIRH1 encodes a functional DEAD-box RNA helicase and plays important roles in defence responses against biotic and abiotic stresses. PMID:18441339

Combined endophytic inoculants enhance nickel phytoextraction from serpentine soil in the hyperaccumulator Noccaea caerulescens

PubMed Central

Visioli, Giovanna; Vamerali, Teofilo; Mattarozzi, Monica; Dramis, Lucia; Sanangelantoni, Anna M.

2015-01-01

This study assesses the effects of specific bacterial endophytes on the phytoextraction capacity of the Ni-hyperaccumulator Noccaea caerulescens, spontaneously growing in a serpentine soil environment. Five metal-tolerant endophytes had already been selected for their high Ni tolerance (6 mM) and plant growth promoting ability. Here we demonstrate that individual bacterial inoculation is ineffective in enhancing Ni translocation and growth of N. caerulescens in serpentine soil, except for specific strains Ncr-1 and Ncr-8, belonging to the Arthrobacter and Microbacterium genera, which showed the highest indole acetic acid production and 1-aminocyclopropane-1-carboxylic acid-deaminase activity. Ncr-1 and Ncr-8 co-inoculation was even more efficient in promoting plant growth, soil Ni removal, and translocation of Ni, together with that of Fe, Co, and Cu. Bacteria of both strains densely colonized the root surfaces and intercellular spaces of leaf epidermal tissue. These two bacterial strains also turned out to stimulate root length, shoot biomass, and Ni uptake in Arabidopsis thaliana grown in MS agar medium supplemented with Ni. It is concluded that adaptation of N. caerulescens in highly Ni-contaminated serpentine soil can be enhanced by an integrated community of bacterial endophytes rather than by single strains; of the former, Arthrobacter and Microbacterium may be useful candidates for future phytoremediation trials in multiple metal-contaminated sites, with possible extension to non-hyperaccumulator plants. PMID:26322074

Combined endophytic inoculants enhance nickel phytoextraction from serpentine soil in the hyperaccumulator Noccaea caerulescens.

PubMed

Visioli, Giovanna; Vamerali, Teofilo; Mattarozzi, Monica; Dramis, Lucia; Sanangelantoni, Anna M

2015-01-01

This study assesses the effects of specific bacterial endophytes on the phytoextraction capacity of the Ni-hyperaccumulator Noccaea caerulescens, spontaneously growing in a serpentine soil environment. Five metal-tolerant endophytes had already been selected for their high Ni tolerance (6 mM) and plant growth promoting ability. Here we demonstrate that individual bacterial inoculation is ineffective in enhancing Ni translocation and growth of N. caerulescens in serpentine soil, except for specific strains Ncr-1 and Ncr-8, belonging to the Arthrobacter and Microbacterium genera, which showed the highest indole acetic acid production and 1-aminocyclopropane-1-carboxylic acid-deaminase activity. Ncr-1 and Ncr-8 co-inoculation was even more efficient in promoting plant growth, soil Ni removal, and translocation of Ni, together with that of Fe, Co, and Cu. Bacteria of both strains densely colonized the root surfaces and intercellular spaces of leaf epidermal tissue. These two bacterial strains also turned out to stimulate root length, shoot biomass, and Ni uptake in Arabidopsis thaliana grown in MS agar medium supplemented with Ni. It is concluded that adaptation of N. caerulescens in highly Ni-contaminated serpentine soil can be enhanced by an integrated community of bacterial endophytes rather than by single strains; of the former, Arthrobacter and Microbacterium may be useful candidates for future phytoremediation trials in multiple metal-contaminated sites, with possible extension to non-hyperaccumulator plants.

Activation of AMP-activated Protein Kinase by Metformin Induces Protein Acetylation in Prostate and Ovarian Cancer Cells*

PubMed Central

Galdieri, Luciano; Gatla, Himavanth; Vancurova, Ivana; Vancura, Ales

2016-01-01

AMP-activated protein kinase (AMPK) is an energy sensor and master regulator of metabolism. AMPK functions as a fuel gauge monitoring systemic and cellular energy status. Activation of AMPK occurs when the intracellular AMP/ATP ratio increases and leads to a metabolic switch from anabolism to catabolism. AMPK phosphorylates and inhibits acetyl-CoA carboxylase (ACC), which catalyzes carboxylation of acetyl-CoA to malonyl-CoA, the first and rate-limiting reaction in de novo synthesis of fatty acids. AMPK thus regulates homeostasis of acetyl-CoA, a key metabolite at the crossroads of metabolism, signaling, chromatin structure, and transcription. Nucleocytosolic concentration of acetyl-CoA affects histone acetylation and links metabolism and chromatin structure. Here we show that activation of AMPK with the widely used antidiabetic drug metformin or with the AMP mimetic 5-aminoimidazole-4-carboxamide ribonucleotide increases the inhibitory phosphorylation of ACC and decreases the conversion of acetyl-CoA to malonyl-CoA, leading to increased protein acetylation and altered gene expression in prostate and ovarian cancer cells. Direct inhibition of ACC with allosteric inhibitor 5-(tetradecyloxy)-2-furoic acid also increases acetylation of histones and non-histone proteins. Because AMPK activation requires liver kinase B1, metformin does not induce protein acetylation in liver kinase B1-deficient cells. Together, our data indicate that AMPK regulates the availability of nucleocytosolic acetyl-CoA for protein acetylation and that AMPK activators, such as metformin, have the capacity to increase protein acetylation and alter patterns of gene expression, further expanding the plethora of metformin's physiological effects. PMID:27733682

Induced Jasmonate Signaling Leads to Contrasting Effects on Root Damage and Herbivore Performance1

PubMed Central

Lu, Jing; Robert, Christelle Aurélie Maud; Riemann, Michael; Cosme, Marco; Mène-Saffrané, Laurent; Massana, Josep; Stout, Michael Joseph; Lou, Yonggen; Gershenzon, Jonathan; Erb, Matthias

2015-01-01

Induced defenses play a key role in plant resistance against leaf feeders. However, very little is known about the signals that are involved in defending plants against root feeders and how they are influenced by abiotic factors. We investigated these aspects for the interaction between rice (Oryza sativa) and two root-feeding insects: the generalist cucumber beetle (Diabrotica balteata) and the more specialized rice water weevil (Lissorhoptrus oryzophilus). Rice plants responded to root attack by increasing the production of jasmonic acid (JA) and abscisic acid, whereas in contrast to in herbivore-attacked leaves, salicylic acid and ethylene levels remained unchanged. The JA response was decoupled from flooding and remained constant over different soil moisture levels. Exogenous application of methyl JA to the roots markedly decreased the performance of both root herbivores, whereas abscisic acid and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid did not have any effect. JA-deficient antisense 13-lipoxygenase (asLOX) and mutant allene oxide cyclase hebiba plants lost more root biomass under attack from both root herbivores. Surprisingly, herbivore weight gain was decreased markedly in asLOX but not hebiba mutant plants, despite the higher root biomass removal. This effect was correlated with a herbivore-induced reduction of sucrose pools in asLOX roots. Taken together, our experiments show that jasmonates are induced signals that protect rice roots from herbivores under varying abiotic conditions and that boosting jasmonate responses can strongly enhance rice resistance against root pests. Furthermore, we show that a rice 13-lipoxygenase regulates root primary metabolites and specifically improves root herbivore growth. PMID:25627217

TAA1-regulated local auxin biosynthesis in the root-apex transition zone mediates the aluminum-induced inhibition of root growth in Arabidopsis.

PubMed

Yang, Zhong-Bao; Geng, Xiaoyu; He, Chunmei; Zhang, Feng; Wang, Rong; Horst, Walter J; Ding, Zhaojun

2014-07-01

The transition zone (TZ) of the root apex is the perception site of Al toxicity. Here, we show that exposure of Arabidopsis thaliana roots to Al induces a localized enhancement of auxin signaling in the root-apex TZ that is dependent on TAA1, which encodes a Trp aminotransferase and regulates auxin biosynthesis. TAA1 is specifically upregulated in the root-apex TZ in response to Al treatment, thus mediating local auxin biosynthesis and inhibition of root growth. The TAA1-regulated local auxin biosynthesis in the root-apex TZ in response to Al stress is dependent on ethylene, as revealed by manipulating ethylene homeostasis via the precursor of ethylene biosynthesis 1-aminocyclopropane-1-carboxylic acid, the inhibitor of ethylene biosynthesis aminoethoxyvinylglycine, or mutant analysis. In response to Al stress, ethylene signaling locally upregulates TAA1 expression and thus auxin responses in the TZ and results in auxin-regulated root growth inhibition through a number of auxin response factors (ARFs). In particular, ARF10 and ARF16 are important in the regulation of cell wall modification-related genes. Our study suggests a mechanism underlying how environmental cues affect root growth plasticity through influencing local auxin biosynthesis and signaling. © 2014 American Society of Plant Biologists. All rights reserved.

Deficiencies in acetyl-CoA carboxylase and fatty acid synthase 1 differentially affect eggshell formation and blood meal digestion in Aedes aegypti.

PubMed

Alabaster, Amy; Isoe, Jun; Zhou, Guoli; Lee, Ada; Murphy, Ashleigh; Day, W Anthony; Miesfeld, Roger L

2011-12-01

To better understand the mechanism of de novo lipid biosynthesis in blood fed Aedes aegypti mosquitoes, we quantitated acetyl-CoA carboxylase (ACC) and fatty acid synthase 1 (FAS1) transcript levels in blood fed mosquitoes, and used RNAi methods to generate ACC and FAS1 deficient mosquitoes. Using the ketogenic amino acid (14)C-leucine as a metabolic precursor of (14)C-acetyl-CoA, we found that (14)C-triacylglycerol and (14)C-phospholipid levels were significantly reduced in both ACC and FAS1 deficient mosquitoes, confirming that ACC and FAS1 are required for de novo lipid biosynthesis after blood feeding. Surprisingly however, we also found that ACC deficient mosquitoes, but not FAS1 deficient mosquitoes, produced defective oocytes, which lacked an intact eggshell and gave rise to inviable eggs. This severe phenotype was restricted to the 1st gonotrophic cycle, suggesting that the eggshell defect was due to ACC deficiencies in the follicular epithelial cells, which are replaced after each gonotrophic cycle. Consistent with lower amounts of de novo lipid biosynthesis, both ACC and FAS1 deficient mosquitoes produced significantly fewer eggs than control mosquitoes in both the 1st and 2nd gonotrophic cycles. Lastly, FAS1 deficient mosquitoes, but not ACC deficient mosquitoes, showed delayed blood meal digestion, suggesting that a feedback control mechanism may coordinate rates of fat body lipid biosynthesis and midgut digestion during feeding. We propose that decreased ACC and FAS1 enzyme levels lead to reduced lipid biosynthesis and lower fecundity, whereas altered levels of the regulatory metabolites acetyl-CoA and malonyl-CoA account for the observed defects in eggshell formation and blood meal digestion, respectively. Copyright © 2011 Elsevier Ltd. All rights reserved.

Deficiencies in acetyl-CoA carboxylase and fatty acid synthase 1 differentially affect eggshell formation and blood meal digestion in Aedes aegypti

PubMed Central

Alabaster, Amy; Isoe, Jun; Zhou, Guoli; Lee, Ada; Murphy, Ashleigh; Day, W. Anthony; Miesfeld, Roger L.

2011-01-01

To better understand the mechanism of de novo lipid biosynthesis in blood fed Ae. aegypti mosquitoes, we quantitated acetyl-CoA carboxylase (ACC) and fatty acid synthase 1 (FAS1) transcript levels in blood fed mosquitoes, and used RNAi methods to generate ACC and FAS1 deficient mosquitoes. Using the ketogenic amino acid 14C-leucine as a metabolic precursor of 14C-acetyl-CoA, we found that 14C-triacylglycerol and 14C-phospholipid levels were significantly reduced in both ACC and FAS1 deficient mosquitoes, confirming that ACC and FAS1 are required for de novo lipid biosynthesis after blood feeding. Surprisingly however, we also found that ACC deficient mosquitoes, but not FAS1 deficient mosquitoes, produced defective oocytes, which lacked an intact eggshell and gave rise to inviable eggs. This severe phenotype was restricted to the 1st gonotrophic cycle, suggesting that the eggshell defect was due to ACC deficiencies in the follicular epithelial cells, which are replaced after each gonotrophic cycle. Consistent with lower amounts of de novo lipid biosynthesis, both ACC and FAS1 deficient mosquitoes produced significantly fewer eggs than control mosquitoes in both the 1st and 2nd gonotrophic cycles. Lastly, FAS1 deficient mosquitoes, but not ACC deficient mosquitoes, showed delayed blood meal digestion, suggesting that a feedback control mechanism may coordinate rates of fat body lipid biosynthesis and midgut digestion during feeding. We propose that decreased ACC and FAS1 enzyme levels lead to reduced lipid biosynthesis and lower fecundity, whereas altered levels of the regulatory metabolites acetyl-CoA and malonyl-CoA account for the observed defects in eggshell formation and blood meal digestion, respectively. PMID:21971482

The draft genome of tropical fruit durian (Durio zibethinus).

PubMed

Teh, Bin Tean; Lim, Kevin; Yong, Chern Han; Ng, Cedric Chuan Young; Rao, Sushma Ramesh; Rajasegaran, Vikneswari; Lim, Weng Khong; Ong, Choon Kiat; Chan, Ki; Cheng, Vincent Kin Yuen; Soh, Poh Sheng; Swarup, Sanjay; Rozen, Steven G; Nagarajan, Niranjan; Tan, Patrick

2017-11-01

Durian (Durio zibethinus) is a Southeast Asian tropical plant known for its hefty, spine-covered fruit and sulfury and onion-like odor. Here we present a draft genome assembly of D. zibethinus, representing the third plant genus in the Malvales order and first in the Helicteroideae subfamily to be sequenced. Single-molecule sequencing and chromosome contact maps enabled assembly of the highly heterozygous durian genome at chromosome-scale resolution. Transcriptomic analysis showed upregulation of sulfur-, ethylene-, and lipid-related pathways in durian fruits. We observed paleopolyploidization events shared by durian and cotton and durian-specific gene expansions in MGL (methionine γ-lyase), associated with production of volatile sulfur compounds (VSCs). MGL and the ethylene-related gene ACS (aminocyclopropane-1-carboxylic acid synthase) were upregulated in fruits concomitantly with their downstream metabolites (VSCs and ethylene), suggesting a potential association between ethylene biosynthesis and methionine regeneration via the Yang cycle. The durian genome provides a resource for tropical fruit biology and agronomy.

Overexpression of ACC gene from oleaginous yeast Lipomyces starkeyi enhanced the lipid accumulation in Saccharomyces cerevisiae with increased levels of glycerol 3-phosphate substrates.

PubMed

Wang, Jiancai; Xu, Ronghua; Wang, Ruling; Haque, Mohammad Enamul; Liu, Aizhong

2016-06-01

The conversion of acetyl-CoA to malonyl-CoA by acetyl-CoA carboxylase (ACC) is the rate-limiting step in fatty acid biosynthesis. In this study, a gene coding for ACC was isolated and characterized from an oleaginous yeast, Lipomyces starkeyi. Real-time quantitative PCR (qPCR) analysis of L. starkeyi acetyl-CoA carboxylase gene (LsACC1) showed that the expression levels were upregulated with the fast accumulation of lipids. The LsACC1 was co-overexpressed with the glycerol 3-phosphate dehydrogenase gene (GPD1), which regulates lipids biosynthesis by supplying another substrates glycerol 3-phosphate for storage lipid assembly, in the non-oleaginous yeast Saccharomyces cerevisiae. Further, the S. cerevisiae acetyl-CoA carboxylase (ScACC1) was transferred with GPD1 and its function was analyzed in comparison with LsACC1. The results showed that overexpressed LsACC1 and GPD1 resulted in a 63% increase in S. cerevisiae. This study gives new data in understanding of the molecular mechanisms underlying the regulation of fatty acids and lipid biosynthesis in yeasts.

Whole genome sequencing and analysis of plant growth promoting bacteria isolated from the rhizosphere of plantation crops coconut, cocoa and arecanut.

PubMed

Gupta, Alka; Gopal, Murali; Thomas, George V; Manikandan, Vinu; Gajewski, John; Thomas, George; Seshagiri, Somasekar; Schuster, Stephan C; Rajesh, Preeti; Gupta, Ravi

2014-01-01

Coconut, cocoa and arecanut are commercial plantation crops that play a vital role in the Indian economy while sustaining the livelihood of more than 10 million Indians. According to 2012 Food and Agricultural organization's report, India is the third largest producer of coconut and it dominates the production of arecanut worldwide. In this study, three Plant Growth Promoting Rhizobacteria (PGPR) from coconut (CPCRI-1), cocoa (CPCRI-2) and arecanut (CPCRI-3) characterized for the PGP activities have been sequenced. The draft genome sizes were 4.7 Mb (56% GC), 5.9 Mb (63.6% GC) and 5.1 Mb (54.8% GB) for CPCRI-1, CPCRI-2, CPCRI-3, respectively. These genomes encoded 4056 (CPCRI-1), 4637 (CPCRI-2) and 4286 (CPCRI-3) protein-coding genes. Phylogenetic analysis revealed that both CPCRI-1 and CPCRI-3 belonged to Enterobacteriaceae family, while, CPCRI-2 was a Pseudomonadaceae family member. Functional annotation of the genes predicted that all three bacteria encoded genes needed for mineral phosphate solubilization, siderophores, acetoin, butanediol, 1-aminocyclopropane-1-carboxylate (ACC) deaminase, chitinase, phenazine, 4-hydroxybenzoate, trehalose and quorum sensing molecules supportive of the plant growth promoting traits observed in the course of their isolation and characterization. Additionally, in all the three CPCRI PGPRs, we identified genes involved in synthesis of hydrogen sulfide (H2S), which recently has been proposed to aid plant growth. The PGPRs also carried genes for central carbohydrate metabolism indicating that the bacteria can efficiently utilize the root exudates and other organic materials as energy source. Genes for production of peroxidases, catalases and superoxide dismutases that confer resistance to oxidative stresses in plants were identified. Besides these, genes for heat shock tolerance, cold shock tolerance and glycine-betaine production that enable bacteria to survive abiotic stress were also identified.

Increased levels of IAA are required for system 2 ethylene synthesis causing fruit softening in peach (Prunus persica L. Batsch)

PubMed Central

Tatsuki, Miho

2013-01-01

The fruit of melting-flesh peach (Prunus persica L. Batsch) cultivars produce high levels of ethylene caused by high expression of PpACS1 (an isogene of 1-aminocyclopropane-1-carboxylic acid synthase), resulting in rapid fruit softening at the late-ripening stage. In contrast, the fruit of stony hard peach cultivars do not soften and produce little ethylene due to low expression of PpACS1. To elucidate the mechanism for suppressing PpACS1 expression in stony hard peaches, a microarray analysis was performed. Several genes that displayed similar expression patterns as PpACS1 were identified and shown to be indole-3-acetic acid (IAA)-inducible genes (Aux/IAA, SAUR). That is, expression of IAA-inducible genes increased at the late-ripening stage in melting flesh peaches; however, these transcripts were low in mature fruit of stony hard peaches. The IAA concentration increased suddenly just before harvest time in melting flesh peaches exactly coinciding with system 2 ethylene production. In contrast, the IAA concentration did not increase in stony hard peaches. Application of 1-naphthalene acetic acid, a synthetic auxin, to stony hard peaches induced a high level of PpACS1 expression, a large amount of ethylene production and softening. Application of an anti-auxin, α-(phenylethyl-2-one)-IAA, to melting flesh peaches reduced levels of PpACS1 expression and ethylene production. These observations indicate that suppression of PpACS1 expression at the late-ripening stage of stony hard peach may result from a low level of IAA and that a high concentration of IAA is required to generate a large amount of system 2 ethylene in peaches. PMID:23364941

Recombinant yeast screen for new inhibitors of human acetyl-CoA carboxylase 2 identifies potential drugs to treat obesity

PubMed Central

Marjanovic, Jasmina; Chalupska, Dominika; Patenode, Caroline; Coster, Adam; Arnold, Evan; Ye, Alice; Anesi, George; Lu, Ying; Okun, Ilya; Tkachenko, Sergey; Haselkorn, Robert; Gornicki, Piotr

2010-01-01

Acetyl-CoA carboxylase (ACC) is a key enzyme of fatty acid metabolism with multiple isozymes often expressed in different eukaryotic cellular compartments. ACC-made malonyl-CoA serves as a precursor for fatty acids; it also regulates fatty acid oxidation and feeding behavior in animals. ACC provides an important target for new drugs to treat human diseases. We have developed an inexpensive nonradioactive high-throughput screening system to identify new ACC inhibitors. The screen uses yeast gene-replacement strains depending for growth on cloned human ACC1 and ACC2. In “proof of concept” experiments, growth of such strains was inhibited by compounds known to target human ACCs. The screen is sensitive and robust. Medium-size chemical libraries yielded new specific inhibitors of human ACC2. The target of the best of these inhibitors was confirmed with in vitro enzymatic assays. This compound is a new drug chemotype inhibiting human ACC2 with 2.8 μM IC50 and having no effect on human ACC1 at 100 μM. PMID:20439761

Alleviation of salt stress by halotolerant and halophilic plant growth-promoting bacteria in wheat (Triticum aestivum).

PubMed

Orhan, Furkan

2016-01-01

In the current study, 18 halotolerant and halophilic bacteria have been investigated for their plant growth promoting abilities in vitro and in a hydroponic culture. The bacterial strains have been investigated for ammonia, indole-3-acetic acid and 1-aminocyclopropane-1-carboxylate-deaminase production, phosphate solubilisation and nitrogen fixation activities. Of the tested bacteria, eight were inoculated with Triticum aestivum in a hydroponic culture. The investigated bacterial strains were found to have different plant-growth promoting activities in vitro. Under salt stress (200mM NaCl), the investigated bacterial strains significantly increased the root and shoot length and total fresh weight of the plants. The growth rates of the plants inoculated with bacterial strains ranged from 62.2% to 78.1%. Identifying of novel halophilic and halotolerant bacteria that promote plant growth can be used as alternatives for salt sensitive plants. Extensive research has been conducted on several halophilic and halotolerant bacterial strains to investigate their plant growth promoting activities. However, to the best of my knowledge, this is the first study to inoculate these bacterial strains with wheat. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Response of jujube fruits to exogenous oxalic acid treatment based on proteomic analysis.

PubMed

Wang, Qing; Lai, Tongfei; Qin, Guozheng; Tian, Shiping

2009-02-01

In this study, we found that oxalic acid (OA) at the concentration of 5 mM could delay jujube fruit sene-scence by reducing ethylene production, repressing fruit reddening and reducing alcohol content, which consequently increased fruit resistance against blue mold caused by Penicillium expansum. In order to gain a further understanding of the mechanism by which OA delays senescence and increases disease resistance of jujube fruit, we used a proteomics approach to compare soluble proteome of jujube fruits treated with water or 5 mM OA for 10 min. A total of 25 differentially expressed proteins were identified by using electrospray ionization quadrupole time-of-flight tandem mass spectrometry (ESI-Q-TOF-MS/MS). Among these proteins, alcohol dehydrogenase 1, which plays a direct role in ethanol metabolism, was repressed, and the abundances of three photosynthesis-related proteins was enhanced in jujube fruit after OA treatment. The protein identified as a cystathionine beta-synthase domain-containing protein, which can regulate ethylene precursors, was also induced by OA treatment. The activity of 1-aminocyclopropane-1-carboxylic acid synthase was significantly suppressed in OA-treated jujube fruit. In addition, three proteins related to the defense/stress response were up-regulated by OA, and contributed to the establishment of systemic resistance induced by OA in jujube fruits. These results indicated that OA treatment might affect ethanol and ethylene metabolism, resulting in delaying senescence, and increase resistance of jujube fruits against fungal pathogens.

40 CFR 180.426 - 2-[4,5-Dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinoline carboxylic acid...

Code of Federal Regulations, 2010 CFR

2010-07-01

...-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinoline carboxylic acid; tolerance for residues. 180.426 Section 180...-Dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinoline carboxylic acid; tolerance for...)-5-oxo-1H-imidazol-2-yl]-3-quinoline carboxylic acid, in or on the raw agricultural commodity soybean...

Efficiency of plant growth-promoting P-solubilizing Bacillus circulans CB7 for enhancement of tomato growth under net house conditions.

PubMed

Mehta, Preeti; Walia, Abhishek; Kulshrestha, Saurabh; Chauhan, Anjali; Shirkot, Chand Karan

2015-01-01

P-solubilizing bacterial isolate CB7 isolated from apple rhizosphere soil of Himachal Pradesh, India was identified as Bacillus circulans on the basis of phenotypic characteristics, biochemical tests, fatty acid methyl esters analysis, and 16S rRNA gene sequence. The isolate exhibited plant growth-promoting traits of P-solubilization, auxin, 1-aminocyclopropane-1-carboxylate deaminase activity, siderophore, nitrogenase activity, and antagonistic activity against Dematophora necatrix. In vitro studies revealed that P-solubilization and other plant growth-promoting traits were dependent on the presence of glucose in PVK medium and removal of yeast extract had no significant effect on plant growth-promoting traits. Plant growth-promoting traits of isolate CB7 were repressed in the presence of KH2 PO4 . P-solubilization activity was associated with the release of organic acids and a drop in the pH of the Pikovskaya's medium. HPLC analysis detected gluconic and citric acid as major organic acids in the course of P-solubilization. Remarkable increase was observed in seed germination (22.32%), shoot length (15.91%), root length (25.10%), shoot dry weight (52.92%) and root dry weight (31.4%), nitrogen (18.75%), potassium (57.69%), and phosphorus (22.22%) content of shoot biomass over control. These results demonstrate that isolate CB7 has the promising PGPR attributes to be developed as a biofertilizer to enhance soil fertility and promote plant growth. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Metabolic Regulation of Invadopodia and Invasion by Acetyl-CoA Carboxylase 1 and De novo Lipogenesis

PubMed Central

Scott, Kristen E. N.; Wheeler, Frances B.; Davis, Amanda L.; Thomas, Michael J.; Ntambi, James M.; Seals, Darren F.; Kridel, Steven J.

2012-01-01

Invadopodia are membrane protrusions that facilitate matrix degradation and cellular invasion. Although lipids have been implicated in several aspects of invadopodia formation, the contributions of de novo fatty acid synthesis and lipogenesis have not been defined. Inhibition of acetyl-CoA carboxylase 1 (ACC1), the committed step of fatty acid synthesis, reduced invadopodia formation in Src-transformed 3T3 (3T3-Src) cells, and also decreased the ability to degrade gelatin. Inhibition of fatty acid synthesis through AMP-activated kinase (AMPK) activation and ACC phosphorylation also decreased invadopodia incidence. The addition of exogenous 16∶0 and 18∶1 fatty acid, products of de novo fatty acid synthesis, restored invadopodia and gelatin degradation to cells with decreased ACC1 activity. Pharmacological inhibition of ACC also altered the phospholipid profile of 3T3-Src cells, with the majority of changes occurring in the phosphatidylcholine (PC) species. Exogenous supplementation with the most abundant PC species, 34∶1 PC, restored invadopodia incidence, the ability to degrade gelatin and the ability to invade through matrigel to cells deficient in ACC1 activity. On the other hand, 30∶0 PC did not restore invadopodia and 36∶2 PC only restored invadopodia incidence and gelatin degradation, but not cellular invasion through matrigel. Pharmacological inhibition of ACC also reduced the ability of MDA-MB-231 breast, Snb19 glioblastoma, and PC-3 prostate cancer cells to invade through matrigel. Invasion of PC-3 cells through matrigel was also restored by 34∶1 PC supplementation. Collectively, the data elucidate the novel metabolic regulation of invadopodia and the invasive process by de novo fatty acid synthesis and lipogenesis. PMID:22238651

Chronic Suppression of Acetyl-CoA Carboxylase 1 in β-Cells Impairs Insulin Secretion via Inhibition of Glucose Rather Than Lipid Metabolism*

PubMed Central

Ronnebaum, Sarah M.; Joseph, Jamie W.; Ilkayeva, Olga; Burgess, Shawn C.; Lu, Danhong; Becker, Thomas C.; Sherry, A. Dean; Newgard, Christopher B.

2008-01-01

Acetyl-CoA carboxylase 1 (ACC1) currently is being investigated as a target for treatment of obesity-associated dyslipidemia and insulin resistance. To investigate the effects of ACC1 inhibition on insulin secretion, three small interfering RNA (siRNA) duplexes targeting ACC1 (siACC1) were transfected into the INS-1-derived cell line, 832/13; the most efficacious duplex was also cloned into an adenovirus and used to transduce isolated rat islets. Delivery of the siACC1 duplexes decreased ACC1 mRNA by 60–80% in 832/13 cells and islets and enzyme activity by 46% compared with cells treated with a non-targeted siRNA. Delivery of siACC1 decreased glucose-stimulated insulin secretion (GSIS) by 70% in 832/13 cells and by 33% in islets. Surprisingly, siACC1 treatment decreased glucose oxidation by 49%, and the ATP:ADP ratio by 52%, accompanied by clear decreases in pyruvate cycling activity and tricarboxylic acid cycle intermediates. Exposure of siACC1-treated cells to the pyruvate cycling substrate dimethylmalate restored GSIS to normal without recovery of the depressed ATP:ADP ratio. In siACC1-treated cells, glucokinase protein levels were decreased by 25%, which correlated with a 36% decrease in glycogen synthesis and a 33% decrease in glycolytic flux. Furthermore, acute addition of the ACC1 inhibitor 5-(tetradecyloxy)-2-furoic acid (TOFA) to β-cells suppressed [14C]glucose incorporation into lipids but had no effect on GSIS, whereas chronic TOFA administration suppressed GSIS and glucose metabolism. In sum, chronic, but not acute, suppression of ACC1 activity impairs GSIS via inhibition of glucose rather than lipid metabolism. These findings raise concerns about the use of ACC inhibitors for diabetes therapy. PMID:18381287

Chronic suppression of acetyl-CoA carboxylase 1 in beta-cells impairs insulin secretion via inhibition of glucose rather than lipid metabolism.

PubMed

Ronnebaum, Sarah M; Joseph, Jamie W; Ilkayeva, Olga; Burgess, Shawn C; Lu, Danhong; Becker, Thomas C; Sherry, A Dean; Newgard, Christopher B

2008-05-23

Acetyl-CoA carboxylase 1 (ACC1) currently is being investigated as a target for treatment of obesity-associated dyslipidemia and insulin resistance. To investigate the effects of ACC1 inhibition on insulin secretion, three small interfering RNA (siRNA) duplexes targeting ACC1 (siACC1) were transfected into the INS-1-derived cell line, 832/13; the most efficacious duplex was also cloned into an adenovirus and used to transduce isolated rat islets. Delivery of the siACC1 duplexes decreased ACC1 mRNA by 60-80% in 832/13 cells and islets and enzyme activity by 46% compared with cells treated with a non-targeted siRNA. Delivery of siACC1 decreased glucose-stimulated insulin secretion (GSIS) by 70% in 832/13 cells and by 33% in islets. Surprisingly, siACC1 treatment decreased glucose oxidation by 49%, and the ATP:ADP ratio by 52%, accompanied by clear decreases in pyruvate cycling activity and tricarboxylic acid cycle intermediates. Exposure of siACC1-treated cells to the pyruvate cycling substrate dimethylmalate restored GSIS to normal without recovery of the depressed ATP:ADP ratio. In siACC1-treated cells, glucokinase protein levels were decreased by 25%, which correlated with a 36% decrease in glycogen synthesis and a 33% decrease in glycolytic flux. Furthermore, acute addition of the ACC1 inhibitor 5-(tetradecyloxy)-2-furoic acid (TOFA) to beta-cells suppressed [(14)C]glucose incorporation into lipids but had no effect on GSIS, whereas chronic TOFA administration suppressed GSIS and glucose metabolism. In sum, chronic, but not acute, suppression of ACC1 activity impairs GSIS via inhibition of glucose rather than lipid metabolism. These findings raise concerns about the use of ACC inhibitors for diabetes therapy.

Soraphen A, an inhibitor of acetyl CoA carboxylase activity, interferes with fatty acid elongation

PubMed Central

Jump, Donald B.; Torres-Gonzalez, Moises; Olson, L. Karl

2010-01-01

Acetyl CoA carboxylase (ACC1 & ACC2) generates malonyl CoA, a substrate for de novo lipogenesis (DNL) and an inhibitor of mitochondrial fatty acid β-oxidation (FAO). Malonyl CoA is also a substrate for microsomal fatty acid elongation, an important pathway for saturated (SFA), mono- (MUFA) and polyunsaturated fatty acid (PUFA) synthesis. Despite the interest in ACC as a target for obesity and cancer therapy, little attention has been given to the role ACC plays in long chain fatty acid synthesis. This report examines the effect of pharmacological inhibition of ACC on DNL & palmitate (16:0) and linoleate (18:2,n-6) metabolism in HepG2 and LnCap cells. The ACC inhibitor, soraphen A, lowers cellular malonyl CoA, attenuates DNL and the formation of fatty acid elongation products derived from exogenous fatty acids, i.e., 16:0 & 18:2,n-6; IC50 ~ 5 nM. Elevated expression of fatty acid elongases (Elovl5, Elovl6) or desaturases (FADS1, FADS2) failed to override the soraphen A effect on SFA, MUFA or PUFA synthesis. Inhibition of fatty acid elongation leads to the accumulation of 16- and 18-carbon unsaturated fatty acids derived from 16:0 and 18:2,n-6, respectively. Pharmacological inhibition of ACC activity will not only attenuate DNL and induce FAO, but will also attenuate the synthesis of very long chain saturated, mono- and polyunsaturated fatty acids. PMID:21184748

ACC oxidase and miRNA 159a, and their involvement in fresh fruit bunch yield (FFB) via sex ratio determination in oil palm.

PubMed

Somyong, Suthasinee; Poopear, Supannee; Sunner, Supreet Kaur; Wanlayaporn, Kitti; Jomchai, Nukoon; Yoocha, Thippawan; Ukoskit, Kittipat; Tangphatsornruang, Sithichoke; Tragoonrung, Somvong

2016-06-01

Oil palm (Elaeis guineesis Jacq.) is the most productive oil-bearing crop, yielding more oil per area than any other oil-bearing crops. However, there are still efforts to improve oil palm yield, in order to serve consumer and manufacturer demand. Oil palm produces female and male inflorescences in an alternating cycle. So, high sex ratio (SR), the ratio of female inflorescences to the total inflorescences, is a favorable trait in term of increasing yields in oil palm. This study aims to understand the genetic control for SR related traits, such as fresh fruit bunch yield (FFB), by characterizing genes at FFB quantitative trait loci (QTLs) on linkage 10 (chromosome 6) and linkage 15 (chromosome 10). Published oil palm sequences at the FFB QTLs were used to develop gene-based and simple sequence repeat (SSR) markers. We used the multiple QTL analysis model (MQM) to characterize the relationship of new markers with the SR traits in the oil palm population. The RNA expression of the most linked QTL genes was also evaluated in various tissues of oil palm. We identified EgACCO1 (encoding aminocyclopropane carboxylate (ACC) oxidase) at chromosome 10 and EgmiR159a (microRNA 159a) at chromosome 6 to be the most linked QTL genes or determinants for FFB yield and/or female inflorescence number with a phenotype variance explained (PVE) from 10.4 to 15 % and suggest that these play the important roles in sex determination and differentiation in oil palm. The strongest expression of EgACCO1 and the predicted precursor of EgmiR159a was found in ovaries and, to a lesser extent, fruit development. In addition, highly normalized expression of EgmiR159a was found in female flowers. In summary, the QTL analysis and the RNA expression reveal that EgACCO1 and EgmiR159a are the potential genetic factors involved in female flower determination and hence would affect yield in oil palm. However, to clarify how these genetic factors regulate female flower determination, more investigation of their down regulation or target may be essential. Additionally, if more sex determination genes controlled by plant hormones are identified, it may possible to reveal a crosstalk of sex determination genes with hormones and environment factors.

Ethylene Promotes Cadmium-induced Root Growth Inhibition through EIN3 controlled XTH33 and LSU1 expression in Arabidopsis.

PubMed

Kong, Xiangpei; Li, Cuiling; Zhang, Feng; Yu, Qianqian; Gao, Shan; Zhang, Maolin; Tian, Huiyu; Zhang, Jian; Yuan, Xianzheng; Ding, Zhaojun

2018-06-05

Cadmium (Cd) stress is one of the most serious heavy metal stresses limiting plant growth and development. However, the molecular mechanisms underlying Cd-induced root growth inhibition remain unclear. Here, we found that ethylene signaling positively regulates Cd-induced root growth inhibition. Arabidopsis seedlings pretreated with the ethylene precursor 1-aminocyclopropane-1-carboxylic acid exhibited enhanced Cd-induced root growth inhibition; while the addition of the ethylene biosynthesis inhibitor aminoethoxyvinyl glycine decreased Cd-induced root growth inhibition. Consistently, ethylene-insensitive mutants such as ein4-1, ein3-1 eil1-1 double mutant, and EBF1ox, displayed an increased tolerance to Cd. Furthermore, we also observed that Cd inhibited EIN3 protein degradation, a process which was regulated by ethylene signaling. Genetic and biochemical analyses showed that EIN3 enhanced root growth inhibition under Cd stress through direct binding to the promoters and regulating the expression of XTH33 and LSU1, which encode key regulators of cell wall extension and S metabolic process, respectively. Collectively, our study demonstrates that ethylene plays a positive role in Cd-regulated root growth inhibition through EIN3-mediated transcriptional regulation of XTH33 and LSU1, and provides a molecular framework for the integration of environmental signals and intrinsic regulators in modulating plant root growth. This article is protected by copyright. All rights reserved.

RCN1-regulated phosphatase activity and EIN2 modulate hypocotyl gravitropism by a mechanism that does not require ethylene signaling.

PubMed

Muday, Gloria K; Brady, Shari R; Argueso, Cristiana; Deruère, Jean; Kieber, Joseph J; DeLong, Alison

2006-08-01

The roots curl in naphthylphthalamic acid1 (rcn1) mutant of Arabidopsis (Arabidopsis thaliana) has altered auxin transport, gravitropism, and ethylene response, providing an opportunity to analyze the interplay between ethylene and auxin in control of seedling growth. Roots of rcn1 seedlings were previously shown to have altered auxin transport, growth, and gravitropism, while rcn1 hypocotyl elongation exhibited enhanced ethylene response. We have characterized auxin transport and gravitropism phenotypes of rcn1 hypocotyls and have explored the roles of auxin and ethylene in controlling these phenotypes. As in roots, auxin transport is increased in etiolated rcn1 hypocotyls. Hypocotyl gravity response is accelerated, although overall elongation is reduced, in etiolated rcn1 hypocotyls. Etiolated, but not light grown, rcn1 seedlings also overproduce ethylene, and mutations conferring ethylene insensitivity restore normal hypocotyl elongation to rcn1. Auxin transport is unaffected by treatment with the ethylene precursor 1-aminocyclopropane carboxylic acid in etiolated hypocotyls of wild-type and rcn1 seedlings. Surprisingly, the ethylene insensitive2-1 (ein2-1) and ein2-5 mutations dramatically reduce gravitropic bending in hypocotyls. However, the ethylene resistant1-3 (etr1-3) mutation does not significantly affect hypocotyl gravity response. Furthermore, neither the etr1 nor the ein2 mutation abrogates the accelerated gravitropism observed in rcn1 hypocotyls, indicating that both wild-type gravity response and enhanced gravity response in rcn1 do not require an intact ethylene-signaling pathway. We therefore conclude that the RCN1 protein affects overall hypocotyl elongation via negative regulation of ethylene synthesis in etiolated seedlings, and that RCN1 and EIN2 modulate hypocotyl gravitropism and ethylene responses through independent pathways.

Characteristics of metal-tolerant plant growth-promoting yeast (Cryptococcus sp. NSE1) and its influence on Cd hyperaccumulator Sedum plumbizincicola.

PubMed

Liu, Wuxing; Wang, Beibei; Wang, Qingling; Hou, Jinyu; Wu, Longhua; Wood, Jennifer L; Luo, Yongming; Franks, Ashley E

2016-09-01

Plant growth-promoting yeasts are often over looked as a mechanism to improve phytoremediation of heavy metals. In this study, Cryptococcus sp. NSE1, a Cd-tolerant yeast with plant growth capabilities, was isolated from the rhizosphere of the heavy metal hyperaccumulator Sedum plumbizincicola. The yeast exhibited strong tolerance to a range of heavy metals including Cd, Cu, and Zn on plate assays. The adsorption rate Cd, Cu, Zn by NSE1 was 26.1, 13.2, and 25.2 %, respectively. Irregular spines were formed on the surface of NSE1 when grown in MSM medium supplemented with 200 mg L(-1) Cd. NSE1 was capable of utilizing 1-aminocyclopropane-1-carboxylate (ACC) as a sole nitrogen source and was capable of solubilization of inorganic phosphate at rates of 195.2 mg L(-1). Field experiments demonstrated that NSE1 increased phytoremediation by increasing the biomass of Cd hyperaccumulator S. plumbizincicola (46 %, p < 0.05) during phytoremediation. Overall, Cd accumulation by S. plumbizincicola was increased from 19.6 to 31.1 mg m(-2) though no difference in the concentration of Cd in the shoot biomass was observed between NSE1 and control. A Cd accumulation ratio of 38.0 % for NSE1 and 17.2 % for control was observed. The HCl-extractable Cd and CaCl2-extractable Cd concentration in the soil of the NSE1 treatment were reduced by 39.2 and 29.5 %, respectively. Community-level physiology profiling, assessed using Biolog Eco plates, indicated functional changes to the rhizosphere community inoculated with NSE1 by average well color development (AWCD) and measurement of richness (diversity). Values of Shannon-Weiner index, Simpson index, and McIntosh index showed a slight but no significant increases. These results indicate that inoculation of NSE1 could increase the shoot biomass of S. plumbizincicola, enhance the Cd accumulation in S. plumbizincicola, and decrease the available heavy metal content in soils significantly without overall significant changes to the microbial community.

Physiological response to drought in radiata pine: phytohormone implication at leaf level.

PubMed

De Diego, N; Pérez-Alfocea, F; Cantero, E; Lacuesta, M; Moncaleán, P

2012-04-01

Pinus radiata D. Don is one of the most abundant species in the north of Spain. Knowledge of drought response mechanisms is essential to guarantee plantation survival under reduced water supply as predicted in the future. Tolerance mechanisms are being studied in breeding programs, because information on such mechanisms can be used for genotype selection. In this paper, we analyze the changes of leaf water potential, hydraulic conductance (K(leaf)), stomatal conductance and phytohormones under drought in P. radiata breeds (O1, O2, O3, O4, O5 and O6) from different climatology areas, hypothesizing that they could show variable drought tolerance. As a primary signal, drought decreased cytokinin (zeatin and zeatin riboside-Z + ZR) levels in needles parallel to K(leaf) and gas exchange. When Z + ZR decreased by 65%, indole-3-acetic acid (IAA) and abscisic acid (ABA) accumulation started as a second signal and increments were higher for IAA than for ABA. When plants decreased by 80%, Z + ZR and K(leaf) doubled their ABA and IAA levels, the photosystem II yield decreased and the electrolyte leakage increased. At the end of the drought period, less tolerant breeds increased IAA over 10-fold compared with controls. External damage also induced jasmonic acid accumulation in all breeds except in O5 (P. radiata var. radiata × var. cedrosensis), which accumulated salicylic acid as a defense mechanism. After rewatering, only the most tolerant plants recovered their K(leaf,) perhaps due to an IAA decrease and 1-aminocyclopropane-1-carboxylic acid maintenance. From all phytohormones, IAA was the most representative 'water deficit signal' in P. radiata.

[A novel gene (Aa-accA ) encoding acetyl-CoA carboxyltransferase alpha-subunit of Alkalimonas amylolytica N10 enhances salt and alkali tolerance of Escherichia coli and tobacco BY-2 cells].

PubMed

Xian, Mingjie; Zhai, Lei; Zhong, Naiqin; Ma, Yiwei; Xue, Yanfen; Ma, Yanhe

2013-08-04

Acetyl-CoA carboxylase (ACC) catalyzes the first step of fatty acid synthesis. In most bacteria, ACC is composed of four subunits encoded by accA, accB, accC, and accD. Of them, accA encodes acetyl-CoA carboxyltransferase alpha-subunit. Our prior work on proteomics of Alkalimonas amylolytica N10 showed that the expression of the Aa-accA has a remarkable response to salt and alkali stress. This research aimed to find out the Aa-accA gene contributing to salt and alkali tolerance. The Aa-accA was amplified by PCR from A. amylolytica N10 and expressed in E. coli K12 host. The effects of Aa-accA expression on the growth of transgenic strains were examined under different NaCl concentration and pH conditions. Transgenic tobacco BY-2 cells harboring Aa-accA were also generated via Agrobacterium-mediated transformation. The viability of BY-2 cells was determined with FDA staining method after salt and alkali shock. The Aa-accA gene product has 318 amino acids and is homologous to the carboxyl transferase domain of acyl-CoA carboxylases. It showed 76% identity with AccA (acetyl-CoA carboxylase carboxyltransferase subunit alpha) from E. coli. Compared to the wild-type strains, transgenic E. coli K12 strain containing Aa-accA showed remarkable growth superiority when grown in increased NaCl concentrations and pH levels. The final cell density of the transgenic strains was 2.6 and 3.5 times higher than that of the control type when they were cultivated in LB medium containing 6% (W/V) NaCl and at pH 9, respectively. Complementary expression of Aa-accA in an accA-depletion E. coli can recover the tolerance of K12 delta accA to salt and alkali stresses to some extent. Similar to the transgenic E. coli, transgenic tobacco BY-2 cells showed higher percentages of viability compared to the wild BY-2 cells under the salt or alkali stress condition. We found that Aa-accA from A. amylolytica N10 overexpression enhances the tolerance of both transgenic E. coli and tobacco BY-2 cells to NaCl and alkali stresses.

Gas chromatographic determination of carboxylic acid chlorides and residual carboxylic acid precursors used in the production of some penicillins.

PubMed

Lauback, R G; Balitz, D F; Mays, D L

1976-05-01

An improved gas chromatographic method is described for the simultaneous determination of carboxylic acid chlorides and related carboxylic acids used in the production of some commercial semisynthetic penicillins. The acid chloride reacts with diethylamine to form the corresponding diethylamide. Carboxylic acid impurities are converted to trimethylsilyl esters. The two derivatives are separated and quantitated in the same chromatographic run. This method, an extension of the earlier procedure of Hishta and Bomstein (1), has been applied to the acid chlorides used to make oxacillin, cloxacillin, dicloxacillin, and methicillin (Figure 1); it shows promise of application to other acid chlorides. The determination is more selective than the usual titration methods, which do not differentiate among acids with similar pK's. Relative standard deviations of the acid chloride determination are 1.0-2.5%. Residual carboxylic acid can be repetitively determined within a range of 0.6% absolute.

Supramolecular architectures in two 1:1 cocrystals of 5-fluorouracil with 5-bromothiophene-2-carboxylic acid and thiophene-2-carboxylic acid.

PubMed

Mohana, Marimuthu; Thomas Muthiah, Packianathan; McMillen, Colin D

2017-06-01

In solid-state engineering, cocrystallization is a strategy actively pursued for pharmaceuticals. Two 1:1 cocrystals of 5-fluorouracil (5FU; systematic name: 5-fluoro-1,3-dihydropyrimidine-2,4-dione), namely 5-fluorouracil-5-bromothiophene-2-carboxylic acid (1/1), C 5 H 3 BrO 2 S·C 4 H 3 FN 2 O 2 , (I), and 5-fluorouracil-thiophene-2-carboxylic acid (1/1), C 4 H 3 FN 2 O 2 ·C 5 H 4 O 2 S, (II), have been synthesized and characterized by single-crystal X-ray diffraction studies. In both cocrystals, carboxylic acid molecules are linked through an acid-acid R 2 2 (8) homosynthon (O-H...O) to form a carboxylic acid dimer and 5FU molecules are connected through two types of base pairs [homosynthon, R 2 2 (8) motif] via a pair of N-H...O hydrogen bonds. The crystal structures are further stabilized by C-H...O interactions in (II) and C-Br...O interactions in (I). In both crystal structures, π-π stacking and C-F...π interactions are also observed.

Construction of the Syngonium podophyllum-Pseudomonas sp. XNN8 Symbiotic Purification System and Investigation of Its Capability of Remediating Uranium Wastewater.

PubMed

Deng, Qin-Wen; Wang, Yong-Dong; Ding, De-Xin; Hu, Nan; Sun, Jing; He, Jia-Dong; Xu, Fei

2017-02-01

The endophyte Pseudomonas sp. XNN8 was separated from Typha orientalis which can secrete indole-3-acetic acid and 1-aminocyclopropane-1-carboxylate deaminase and siderophores and has strong resistance to uranium it was then colonized in the Syngonium podophyllum; and the S. podophyllum-Pseudomonas sp. XNN8 symbiotic purification system (SPPSPS) for uranium-containing wastewater was constructed. Afterwards, the hydroponic experiments to remove uranium from uranium-containing wastewater by the SPPSPS were conducted. After 24 days of treatment, the uranium concentrations of the wastewater samples with uranium concentrations between 0.5 and 5.0 mg/L were lowered to below 0.05 mg/L. Furthermore, the uranium in the plants was assayed using Fourier transform infrared spectroscopy (FTIR) and extended X-ray absorption fine structure (EXAFS) spectroscopy. The Pseudomonas sp. XNN8 was found to generate substantial organic groups in the roots of the Syngonium podophyllum, which could improve the complexing capability of S. podophyllum for uranium. The uranium in the roots of S. podophyllum was found to be the uranyl phosphate (47.4 %) and uranyl acetate (52.6 %).

Resistance of Malus domestica fruit to Botrytis cinerea depends on endogenous ethylene biosynthesis.

PubMed

Akagi, Aya; Dandekar, Abhaya M; Stotz, Henrik U

2011-11-01

The plant hormone ethylene regulates fruit ripening, other developmental processes, and a subset of defense responses. Here, we show that 1-aminocyclopropane-1-carboxylic acid synthase (ACS)-silenced apple (Malus domestica) fruit that express a sense construct of ACS were more susceptible to Botrytis cinerea than untransformed apple, demonstrating that ethylene strengthens fruit resistance to B. cinerea infection. Because ethylene response factors (ERFs) are known to contribute to resistance against B. cinerea via the ethylene-signaling pathway, we cloned four ERF cDNAs from fruit of M. domestica: MdERF3, -4, -5, and -6. Expression of all four MdERF mRNAs was ethylene dependent and induced by wounding or by B. cinerea infection. B. cinerea infection suppressed rapid induction of wound-related MdERF expression. MdERF3 was the only mRNA induced by wounding and B. cinerea infection in ACS-suppressed apple fruit, although its induction was reduced compared with wild-type apple. Promoter regions of all four MdERF genes were cloned and putative cis-elements were identified in each promoter. Transient expression of MdERF3 in tobacco increased expression of the GCC-box containing gene chitinase 48.

Transgenic analysis reveals LeACS-1 as a positive regulator of ethylene-induced shikonin biosynthesis in Lithospermum erythrorhizon hairy roots.

PubMed

Fang, Rongjun; Wu, Fengyao; Zou, Ailan; Zhu, Yu; Zhao, Hua; Zhao, Hu; Liao, Yonghui; Tang, Ren-Jie; Yang, Tongyi; Pang, Yanjun; Wang, Xiaoming; Yang, Rongwu; Qi, Jinliang; Lu, Guihua; Yang, Yonghua

2016-03-01

The phytohormone ethylene (ET) is a crucial signaling molecule that induces the biosynthesis of shikonin and its derivatives in Lithospermum erythrorhizon shoot cultures. However, the molecular mechanism and the positive regulators involved in this physiological process are largely unknown. In this study, the function of LeACS-1, a key gene encoding the 1-aminocyclopropane-1-carboxylic acid synthase for ET biosynthesis in L. erythrorhizon hairy roots, was characterized by using overexpression and RNA interference (RNAi) strategies. The results showed that overexpression of LeACS-1 significantly increased endogenous ET concentration and shikonin production, consistent with the up-regulated genes involved in ET biosynthesis and transduction, as well as the genes related to shikonin biosynthesis. Conversely, RNAi of LeACS-1 effectively decreased endogenous ET concentration and shikonin production and down-regulated the expression level of above genes. Correlation analysis showed a significant positive linear relationship between ET concentration and shikonin production. All these results suggest that LeACS-1 acts as a positive regulator of ethylene-induced shikonin biosynthesis in L. erythrorhizon hairy roots. Our work not only gives new insights into the understanding of the relationship between ET and shikonin biosynthesis, but also provides an efficient genetic engineering target gene for secondary metabolite production in non-model plant L. erythrorhizon.

Plant Growth Enhancement, Disease Resistance, and Elemental Modulatory Effects of Plant Probiotic Endophytic Bacillus sp. Fcl1.

PubMed

Jayakumar, Aswathy; Krishna, Arathy; Mohan, Mahesh; Nair, Indu C; Radhakrishnan, E K

2018-04-13

Endophytic bacteria have already been studied for their beneficial support to plants to manage both biotic and abiotic stress through an array of well-established mechanisms. They have either direct or indirect impact on mobilizing diverse nutrients and elements from soil to plants. However, detailed insight into the fine-tuning of plant elemental composition by associated microorganism is very limited. In this study, endophytic Bacillus Fcl1 characterized from the rhizome of Curcuma longa was found to have broad range of plant growth-promoting and biocontrol mechanisms. The organism was found to have indole acetic acid and 1-aminocyclopropane-1-carboxylate deaminase production properties along with nitrogen fixation. The Bacillus Fcl1 could also inhibit diverse phytopathogens as confirmed by dual culture and well diffusion. By LC-MS/MS analysis, chemical basis of its antifungal activity has been proved to be due to the production of iturin A and a blend of surfactin compounds. Moreover, the organism was found to induce both plant growth and disease resistance in vivo in model plant system. Because of these experimentally demonstrated multiple plant probiotic features, Bacillus Fcl1 was selected as a candidate organism to study its role in modulation of plant elemental composition. ICP-MS analysis of Bacillus Fcl1-treated plants provided insight into relation of bacterial interaction with elemental composition of plants.

Characterization of a versatile rhizospheric organism from cucumber identified as Ochrobactrum haematophilum.

PubMed

Zhao, Lei; Teng, Songshan; Liu, Yanping

2012-04-01

Several rhizobacteria play a vital role in promoting plant growth and protecting plants against fungal diseases and degrading pesticides in the environment. In this study, a bacterial strain, designated H10, was isolated from the rhizosphere at Laixi in Shandong Province, China, and was identified as Ochrobactrum haematophilum based on API 20 NE tests and 16S rRNA gene sequence analysis. The plant growth-promoting characteristics of the strain were further characterized, and the results showed that strain H10 produces siderophore, indol-3-acetic (IAA) and solubilized phosphate but lacks 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. Inoculation with the strain was found to significantly increase (p < 0.05) the growth of cucumber in pot experiments. Strain H10 was assessed in vitro for antagonism against several pathogenic fungi and showed high antifungal activity. The cell-free culture filtrates, which had high extracellular chitinase, β-1,3-glucanase and protease activities, could inhibit the growth of all pathogenic fungi tested, indicating that growth suppression was partly due to extracellular antifungal metabolites present in the culture filtrates. Changes in hyphal morphology were observed in phytopathogenic fungi after treatment with the culture filtrates. Additionally, strain H10 was able to degrade 80%, 85% and 58% of the pesticides chlorpyrifos, β-cypermethrin and imidacloprid, respectively, within 60 h in liquid culture. The inoculation of strain H10 into soil treated with 100 mg kg(-1) of the three pesticides accordingly resulted in a higher degradation rate than in noninoculated soils. These results highlight the potential of this bacterium for use as a biofertilizer and biopesticide and suggest that it may provide an alternative to the use of chemical fertilizers and pesticides in agriculture. Additionally, it may represent a bioremediation agent that can remove contaminating chemical pesticide residues from the environment. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multilayered Regulation of Ethylene Induction Plays a Positive Role in Arabidopsis Resistance against Pseudomonas syringae.

PubMed

Guan, Rongxia; Su, Jianbin; Meng, Xiangzong; Li, Sen; Liu, Yidong; Xu, Juan; Zhang, Shuqun

2015-09-01

Ethylene, a key phytohormone involved in plant-pathogen interaction, plays a positive role in plant resistance against fungal pathogens. However, its function in plant bacterial resistance remains unclear. Here, we report a detailed analysis of ethylene induction in Arabidopsis (Arabidopsis thaliana) in response to Pseudomonas syringae pv tomato DC3000 (Pst). Ethylene biosynthesis is highly induced in both pathogen/microbe-associated molecular pattern (PAMP)-triggered immunity and effector-triggered immunity (ETI), and the induction is potentiated by salicylic acid (SA) pretreatment. In addition, Pst actively suppresses PAMP-triggered ethylene induction in a type III secretion system-dependent manner. SA potentiation of ethylene induction is dependent mostly on MITOGEN-ACTIVATED PROTEIN KINASE6 (MPK6) and MPK3 and their downstream ACS2 and ACS6, two type I isoforms of 1-aminocyclopropane-1-carboxylic acid synthases (ACSs). ACS7, a type III ACS whose expression is enhanced by SA pretreatment, is also involved. Pst expressing the avrRpt2 effector gene (Pst-avrRpt2), which is capable of triggering ETI, induces a higher level of ethylene production, and the elevated portion is dependent on SALICYLIC ACID INDUCTION DEFICIENT2 and NONEXPRESSER OF PATHOGENESIS-RELATED GENE1, two key players in SA biosynthesis and signaling. High-order ACS mutants with reduced ethylene induction are more susceptible to both Pst and Pst-avrRpt2, demonstrating a positive role of ethylene in plant bacterial resistance mediated by both PAMP-triggered immunity and ETI. © 2015 American Society of Plant Biologists. All Rights Reserved.

Plant Growth Promoting Rhizobacteria in Amelioration of Salinity Stress: A Systems Biology Perspective

PubMed Central

Ilangumaran, Gayathri; Smith, Donald L.

2017-01-01

Salinity affects plant growth and is a major abiotic stress that limits crop productivity. It is well-understood that environmental adaptations and genetic traits regulate salinity tolerance in plants, but imparting the knowledge gained towards crop improvement remain arduous. Harnessing the potential of beneficial microorganisms present in the rhizosphere is an alternative strategy for improving plant stress tolerance. This review intends to elucidate the understanding of salinity tolerance mechanisms attributed by plant growth promoting rhizobacteria (PGPR). Recent advances in molecular studies have yielded insights into the signaling networks of plant–microbe interactions that contribute to salt tolerance. The beneficial effects of PGPR involve boosting key physiological processes, including water and nutrient uptake, photosynthesis, and source-sink relationships that promote growth and development. The regulation of osmotic balance and ion homeostasis by PGPR are conducted through modulation of phytohormone status, gene expression, protein function, and metabolite synthesis in plants. As a result, improved antioxidant activity, osmolyte accumulation, proton transport machinery, salt compartmentalization, and nutrient status reduce osmotic stress and ion toxicity. Furthermore, in addition to indole-3-acetic acid and 1-aminocyclopropane-1-carboxylic acid deaminase biosynthesis, other extracellular secretions of the rhizobacteria function as signaling molecules and elicit stress responsive pathways. Application of PGPR inoculants is a promising measure to combat salinity in agricultural fields, thereby increasing global food production. PMID:29109733

Inoculation of Brassica oxyrrhina with plant growth promoting bacteria for the improvement of heavy metal phytoremediation under drought conditions.

PubMed

Ma, Ying; Rajkumar, Mani; Zhang, Chang; Freitas, Helena

2016-12-15

The aim of this study was to investigate the effects of drought resistant serpentine rhizobacteria on plant growth and metal uptake by Brassica oxyrrhina under drought stress (DS) condition. Two drought resistant serpentine rhizobacterial strains namely Pseudomonas libanensis TR1 and Pseudomonas reactans Ph3R3 were selected based on their ability to stimulate seedling growth in roll towel assay. Further assessment on plant growth promoting (PGP) parameters revealed their ability to produce indole-3-acetic acid, siderophore and 1-aminocyclopropane-1-carboxylate deaminase. Moreover, both strains exhibited high resistance to various heavy metals, antibiotics, salinity and extreme temperature. Inoculation of TR1 and Ph3R3 significantly increased plant growth, leaf relative water and pigment content of B. oxyrrhina, whereas decreased concentrations of proline and malondialdehyde in leaves under metal stress in the absence and presence of DS. Regardless of soil water conditions, TR1 and Ph3R3 greatly improved organ metal concentrations, translocation and bioconcentration factors of Cu and Zn. The successful colonization and metabolic activities of P. libanensis TR1 and P. reactans Ph3R3 represented positive effects on plant development and metal phytoremediation under DS. These results indicate that these strains could be used as bio-inoculants for the improvement of phytoremediation of metal polluted soils under semiarid conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

Early steps of adventitious rooting: morphology, hormonal profiling and carbohydrate turnover in carnation stem cuttings.

PubMed

Agulló-Antón, María Ángeles; Ferrández-Ayela, Almudena; Fernández-García, Nieves; Nicolás, Carlos; Albacete, Alfonso; Pérez-Alfocea, Francisco; Sánchez-Bravo, José; Pérez-Pérez, José Manuel; Acosta, Manuel

2014-03-01

The rooting of stem cuttings is a common vegetative propagation practice in many ornamental species. A detailed analysis of the morphological changes occurring in the basal region of cultivated carnation cuttings during the early stages of adventitious rooting was carried out and the physiological modifications induced by exogenous auxin application were studied. To this end, the endogenous concentrations of five major classes of plant hormones [auxin, cytokinin (CK), abscisic acid, salicylic acid (SA) and jasmonic acid] and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid were analyzed at the base of stem cuttings and at different stages of adventitious root formation. We found that the stimulus triggering the initiation of adventitious root formation occurred during the first hours after their excision from the donor plant, due to the breakdown of the vascular continuum that induces auxin accumulation near the wounding. Although this stimulus was independent of exogenously applied auxin, it was observed that the auxin treatment accelerated cell division in the cambium and increased the sucrolytic activities at the base of the stem, both of which contributed to the establishment of the new root primordia at the stem base. Further, several genes involved in auxin transport were upregulated in the stem base either with or without auxin application, while endogenous CK and SA concentrations were specially affected by exogenous auxin application. Taken together our results indicate significant crosstalk between auxin levels, stress hormone homeostasis and sugar availability in the base of the stem cuttings in carnation during the initial steps of adventitious rooting. © 2013 Scandinavian Plant Physiology Society.

The Chloroplast-Localized Phospholipases D α4 and α5 Regulate Herbivore-Induced Direct and Indirect Defenses in Rice1[C][W

PubMed Central

Qi, Jinfeng; Zhou, Guoxin; Yang, Lijuan; Erb, Matthias; Lu, Yanhua; Sun, Xiaoling; Cheng, Jiaan; Lou, Yonggen

2011-01-01

The oxylipin pathway is of central importance for plant defensive responses. Yet, the first step of the pathway, the liberation of linolenic acid following induction, is poorly understood. Phospholipases D (PLDs) have been hypothesized to mediate this process, but data from Arabidopsis (Arabidopsis thaliana) regarding the role of PLDs in plant resistance have remained controversial. Here, we cloned two chloroplast-localized PLD genes from rice (Oryza sativa), OsPLDα4 and OsPLDα5, both of which were up-regulated in response to feeding by the rice striped stem borer (SSB) Chilo suppressalis, mechanical wounding, and treatment with jasmonic acid (JA). Antisense expression of OsPLDα4 and -α5 (as-pld), which resulted in a 50% reduction of the expression of the two genes, reduced elicited levels of linolenic acid, JA, green leaf volatiles, and ethylene and attenuated the SSB-induced expression of a mitogen-activated protein kinase (OsMPK3), a lipoxygenase (OsHI-LOX), a hydroperoxide lyase (OsHPL3), as well as a 1-aminocyclopropane-1-carboxylic acid synthase (OsACS2). The impaired oxylipin and ethylene signaling in as-pld plants decreased the levels of herbivore-induced trypsin protease inhibitors and volatiles, improved the performance of SSB and the rice brown planthopper Nilaparvata lugens, and reduced the attractiveness of plants to a larval parasitoid of SSB, Apanteles chilonis. The production of trypsin protease inhibitors in as-pld plants could be partially restored by JA, while the resistance to rice brown planthopper and SSB was restored by green leaf volatile application. Our results show that phospholipases function as important components of herbivore-induced direct and indirect defenses in rice. PMID:21984727

A phytobeneficial strain Planomicrobium sp. MSSA-10 triggered oxidative stress responsive mechanisms and regulated the growth of pea plants under induced saline environment.

PubMed

Shahid, M; Akram, M S; Khan, M A; Zubair, M; Shah, S M; Ismail, M; Shabir, G; Basheer, S; Aslam, K; Tariq, M

2018-06-01

The study was planned to characterize Planomicrobium sp. MSSA-10 for plant-beneficial traits and to evaluate its inoculation impact on physiology of pea plants under different salinity levels. Strain MSSA-10 was isolated from pea rhizosphere and identified by the analysis of 16S rRNA gene sequence. The strain demonstrated phosphate solubilization and auxin production up to 2 mol l -1 NaCl and exhibited 1-aminocyclopropane-1-carboxylic acid deaminase activity up to 1·5 mol l -1 salt. In an inoculation experiment under different salinity regimes, a significant increase in growth was observed associated with decreased levels of reactive oxygen species and enhanced antioxidative enzyme activities. The strain also promoted the translocation of nutrients in plants with subsequent increase in chlorophyll and protein contents as compared to noninoculated plants. It has been observed that rifampicin-resistant derivatives of MSSA-10 were able to survive for 30 days at optimum cell density with pea rhizosphere. Growth-stimulating effect of MSSA-10 on pea plants may be attributed to its rhizosphere competence, nutrient mobilization and modulation of plant oxidative damage repair mechanisms under saline environment. Planomicrobium sp. MSSA-10 might be used as potent bioinoculant to relieve pea plants from deleterious effects of salinity. © 2018 The Society for Applied Microbiology.

After-Ripening Induced Transcriptional Changes of Hormonal Genes in Wheat Seeds: The Cases of Brassinosteroids, Ethylene, Cytokinin and Salicylic Acid

PubMed Central

Yao, Zhen; Jordan, Mark C.; Park, Seokhoon; Ayele, Belay T.

2014-01-01

Maintenance and release of seed dormancy is regulated by plant hormones; their levels and seed sensitivity being the critical factors. This study reports transcriptional regulation of brassinosteroids (BR), ethylene (ET), cytokinin (CK) and salicylic acid (SA) related wheat genes by after-ripening, a period of dry storage that decays dormancy. Changes in the expression of hormonal genes due to seed after-ripening did not occur in the anhydrobiotic state but rather in the hydrated state. After-ripening induced dormancy decay appears to be associated with imbibition mediated increase in the synthesis and signalling of BR, via transcriptional activation of de-etiolated2, dwarf4 and brassinosteroid signaling kinase, and repression of brassinosteroid insensitive 2. Our analysis is also suggestive of the significance of increased ET production, as reflected by enhanced transcription of 1-aminocyclopropane-1-carboxylic acid oxidase in after-ripened seeds, and tight regulation of seed response to ET in regulating dormancy decay. Differential transcriptions of lonely guy, zeatin O-glucosyltransferases and cytokinin oxidases, and pseudo-response regulator between dormant and after-ripened seeds implicate CK in the regulation of seed dormancy in wheat. Our analysis also reflects the association of dormancy decay in wheat with seed SA level and NPR independent SA signaling that appear to be regulated transcriptionally by phenylalanine ammonia lyase, and whirly and suppressor of npr1 inducible1 genes, respectively. Co-expression clustering of the hormonal genes implies the significance of synergistic and antagonistic interaction between the different plant hormones in regulating wheat seed dormancy. These results contribute to further our understanding of the molecular features controlling seed dormancy in wheat. PMID:24498132

Ethylene Signaling Negatively Regulates Freezing Tolerance by Repressing Expression of CBF and Type-A ARR Genes in Arabidopsis[W][OA

PubMed Central

Shi, Yiting; Tian, Shouwei; Hou, Lingyan; Huang, Xiaozhen; Zhang, Xiaoyan; Guo, Hongwei; Yang, Shuhua

2012-01-01

The phytohormone ethylene regulates multiple aspects of plant growth and development and responses to environmental stress. However, the exact role of ethylene in freezing stress remains unclear. Here, we report that ethylene negatively regulates plant responses to freezing stress in Arabidopsis thaliana. Freezing tolerance was decreased in ethylene overproducer1 and by the application of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid but increased by the addition of the ethylene biosynthesis inhibitor aminoethoxyvinyl glycine or the perception antagonist Ag+. Furthermore, ethylene-insensitive mutants, including etr1-1, ein4-1, ein2-5, ein3-1, and ein3 eil1, displayed enhanced freezing tolerance. By contrast, the constitutive ethylene response mutant ctr1-1 and EIN3-overexpressing plants exhibited reduced freezing tolerance. Genetic and biochemical analyses revealed that EIN3 negatively regulates the expression of CBFs and type-A Arabidopsis response regulator5 (ARR5), ARR7, and ARR15 by binding to specific elements in their promoters. Overexpression of these ARR genes enhanced the freezing tolerance of plants. Thus, our study demonstrates that ethylene negatively regulates cold signaling at least partially through the direct transcriptional control of cold-regulated CBFs and type-A ARR genes by EIN3. Our study also provides evidence that type-A ARRs function as key nodes to integrate ethylene and cytokinin signaling in regulation of plant responses to environmental stress. PMID:22706288

Stevioside improves pancreatic beta-cell function during glucotoxicity via regulation of acetyl-CoA carboxylase.

PubMed

Chen, Jianguo; Jeppesen, Per Bendix; Nordentoft, Iver; Hermansen, Kjeld

2007-06-01

Chronic hyperglycemia is detrimental to pancreatic beta-cells, causing impaired insulin secretion and beta-cell turnover. The characteristic secretory defects are increased basal insulin secretion (BIS) and a selective loss of glucose-stimulated insulin secretion (GSIS). Several recent studies support the view that the acetyl-CoA carboxylase (ACC) plays a pivotal role for GSIS. We have shown that stevioside (SVS) enhances insulin secretion and ACC gene expression. Whether glucotoxicity influences ACC and whether this action can be counteracted by SVS are not known. To investigate this, we exposed isolated mouse islets as well as clonal INS-1E beta-cells for 48 h to 27 or 16.7 mM glucose, respectively. We found that 48-h exposure to high glucose impairs GSIS from mouse islets and INS-1E cells, an effect that is partly counteracted by SVS. The ACC dephosphorylation inhibitor okadaic acid (OKA, 10(-8) M), and 5-aminoimidazole-4-carboxamide-1-beta-d-ribofuranoside (AICAR, 10(-4) M), an activator of 5'-AMP protein kinase that phosphorylates ACC, eliminated the beneficial effect of SVS. 5-Tetrade-cyloxy-2-furancarboxylic acid (TOFA), the specific ACC inhibitor, blocked the effect of SVS as well. During glucotoxity, ACC gene expression, ACC protein, and phosphorylated ACC protein were increased in INS-1E beta-cells. SVS pretreatment further increased ACC gene expression with strikingly elevated ACC activity and increased glucose uptake accompanied by enhanced GSIS. Our studies show that glucose is a potent stimulator of ACC and that SVS to some extent counteracts glucotoxicity via increased ACC activity. SVS possesses the potential to alleviate negative effects of glucotoxicity in beta-cells via a unique mechanism of action.

Characterization and diagenesis of strong-acid carboxyl groups in humic substances

USGS Publications Warehouse

Leenheer, J.A.; Wershaw, R. L.; Brown, G.K.; Reddy, M.M.

2003-01-01

A small fraction of carboxylic acid functional groups in humic substances are exceptionally acidic with pKa values as low as 0.5. A review of acid-group theory eliminated most models and explanations for these exceptionally acidic carboxyl groups. These acidic carboxyl groups in Suwannee River fulvic acid were enriched by a 2-stage fractionation process and the fractions were characterized by elemental, molecular-weight, and titrimetric analyses, and by infrared and 13C- and 1H-nuclear magnetic resonance spectrometry. An average structural model of the most acidic fraction derived from the characterization data indicated a high density of carboxyl groups clustered on oxygen-heterocycle alicyclic rings. Intramolecular H-bonding between adjacent carboxyl groups in these ring structures enhanced stabilization of the carboxylate anion which results in low pKa1 values. The standard, tetrahydrofuran tetracarboxylic acid, was shown to have similar acidity characteristics to the highly acidic fulvic acid fraction. The end products of 3 known diagenetic pathways for the formation of humic substances were shown to result in carboxyl groups clustered on oxygen-heterocycle alicyclic rings.

Carboxylic Acids Plasma Membrane Transporters in Saccharomyces cerevisiae.

PubMed

Casal, Margarida; Queirós, Odília; Talaia, Gabriel; Ribas, David; Paiva, Sandra

2016-01-01

This chapter covers the functionally characterized plasma membrane carboxylic acids transporters Jen1, Ady2, Fps1 and Pdr12 in the yeast Saccharomyces cerevisiae, addressing also their homologues in other microorganisms, as filamentous fungi and bacteria. Carboxylic acids can either be transported into the cells, to be used as nutrients, or extruded in response to acid stress conditions. The secondary active transporters Jen1 and Ady2 can mediate the uptake of the anionic form of these substrates by a H(+)-symport mechanism. The undissociated form of carboxylic acids is lipid-soluble, crossing the plasma membrane by simple diffusion. Furthermore, acetic acid can also be transported by facilitated diffusion via Fps1 channel. At the cytoplasmic physiological pH, the anionic form of the acid prevails and it can be exported by the Pdr12 pump. This review will highlight the mechanisms involving carboxylic acids transporters, and the way they operate according to the yeast cell response to environmental changes, as carbon source availability, extracellular pH and acid stress conditions.

Synthesis of the 1-Monoester of 2-Ketoalkanedioic Acids, e.g., Octyl α-Ketoglutarate

PubMed Central

Jung, Michael E.; Deng, Gang

2012-01-01

Oxidative cleavage of cycloalkene-1-carboxylates, made from the corresponding carboxylic acids, and subsequent oxidation of the resulting ketoaldehyde afforded the important 1-monoesters of 2-ketoalkanedioic acids. Thus ozonolysis of octyl cyclobutene-1-carboxylate followed by sodium chlorite oxidation afforded the 1-monooctyl 2-ketoglutarate. This is a cell-permeable prodrug form of α-ketoglutarate, an important intermediate in the tricarboxylic acid (TCA, Krebs) cycle and a promising therapeutic agent in its own right. PMID:23163977

1-Aminocyclopentane-1,2,4-tricarboxylic acids screening on glutamatergic and serotonergic systems.

PubMed

Gelmi, Maria Luisa; Caputo, Francesco; Clerici, Francesca; Pellegrino, Sara; Giannaccini, Gino; Betti, Laura; Fabbrini, Laura; Schmid, Lara; Palego, Lionella; Lucacchini, Antonio

2007-12-15

Enantiopure constrained 1-aminocyclopentane-1,2,4-tricarboxylic acids containing the glutamic acid skeleton were prepared as two diastereomers characterized by having the carboxylic groups in position two and four cis-oriented to each other and trans with respect to 1-carboxylic group and all cis-oriented carboxylic groups, respectively. A biochemical screening of activity of the above amino acids was investigated on glutamate and 5-HT receptors to find a possible metabotropic agonist, acting on the serotoninergic system.

Prevalence of type III secretion system in effective biocontrol pseudomonads.

PubMed

Almario, Juliana; Gobbin, Davide; Défago, Geneviève; Moënne-Loccoz, Yvan; Rezzonico, Fabio

2014-05-01

Functional type III secretion system (T3SS) genes are needed for effective biocontrol of Pythium damping-off of cucumber by Pseudomonas fluorescens KD, but whether biocontrol Pseudomonas strains with T3SS genes display overall a higher plant-protecting activity is unknown. The assessment of 198 biocontrol fluorescent pseudomonads originating from 60 soils worldwide indicated that 32% harbour the ATPase-encoding T3SS gene hrcN, which was most often found in tomato isolates. The hrcN(+) biocontrol strains (and especially those also producing 2,4-diacetylphloroglucinol and displaying 1-aminocyclopropane-1-carboxylate deaminase activity) displayed higher plant-protecting ability in comparison with hrcN(-) biocontrol strains, both in the Pythium/cucumber and Fusarium/cucumber pathosystems. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Induced jasmonate signaling leads to contrasting effects on root damage and herbivore performance.

PubMed

Lu, Jing; Robert, Christelle Aurélie Maud; Riemann, Michael; Cosme, Marco; Mène-Saffrané, Laurent; Massana, Josep; Stout, Michael Joseph; Lou, Yonggen; Gershenzon, Jonathan; Erb, Matthias

2015-03-01

Induced defenses play a key role in plant resistance against leaf feeders. However, very little is known about the signals that are involved in defending plants against root feeders and how they are influenced by abiotic factors. We investigated these aspects for the interaction between rice (Oryza sativa) and two root-feeding insects: the generalist cucumber beetle (Diabrotica balteata) and the more specialized rice water weevil (Lissorhoptrus oryzophilus). Rice plants responded to root attack by increasing the production of jasmonic acid (JA) and abscisic acid, whereas in contrast to in herbivore-attacked leaves, salicylic acid and ethylene levels remained unchanged. The JA response was decoupled from flooding and remained constant over different soil moisture levels. Exogenous application of methyl JA to the roots markedly decreased the performance of both root herbivores, whereas abscisic acid and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid did not have any effect. JA-deficient antisense 13-lipoxygenase (asLOX) and mutant allene oxide cyclase hebiba plants lost more root biomass under attack from both root herbivores. Surprisingly, herbivore weight gain was decreased markedly in asLOX but not hebiba mutant plants, despite the higher root biomass removal. This effect was correlated with a herbivore-induced reduction of sucrose pools in asLOX roots. Taken together, our experiments show that jasmonates are induced signals that protect rice roots from herbivores under varying abiotic conditions and that boosting jasmonate responses can strongly enhance rice resistance against root pests. Furthermore, we show that a rice 13-lipoxygenase regulates root primary metabolites and specifically improves root herbivore growth. © 2015 American Society of Plant Biologists. All Rights Reserved.

40 CFR 721.2950 - Carboxylic acid glycidyl esters.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Carboxylic acid glycidyl esters. 721... Substances § 721.2950 Carboxylic acid glycidyl esters. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as carboxylic acid glycidyl ester...

Construction of a recombinant strain of Pseudomonas fluorescens producing both phenazine-1-carboxylic acid and cyclic lipopeptide for the biocontrol of take-all disease of wheat.

USDA-ARS?s Scientific Manuscript database

The primary mechanism of biocontrol by Pseudomonas fluorescens strains HC1-07 and HC9-07 is production of a cyclic lipopeptide (CLP) and phenazine-1-carboxylic acid, respectively. We introduced the seven-gene operon for the synthesis of phenazine-1-carboxylic acid (PCA) from P. synxantha 2-79 into P...

Complex phytohormone responses during the cold acclimation of two wheat cultivars differing in cold tolerance, winter Samanta and spring Sandra.

PubMed

Kosová, Klára; Prášil, Ilja Tom; Vítámvás, Pavel; Dobrev, Petre; Motyka, Václav; Floková, Kristýna; Novák, Ondřej; Turečková, Veronika; Rolčik, Jakub; Pešek, Bedřich; Trávničková, Alena; Gaudinová, Alena; Galiba, Gabor; Janda, Tibor; Vlasáková, Eva; Prášilová, Pavla; Vanková, Radomíra

2012-04-15

Hormonal changes accompanying the cold stress (4°C) response that are related to the level of frost tolerance (FT; measured as LT50) and the content of the most abundant dehydrin, WCS120, were compared in the leaves and crowns of the winter wheat (Triticum aestivum L.) cv. Samanta and the spring wheat cv. Sandra. The characteristic feature of the alarm phase (1 day) response was a rapid elevation of abscisic acid (ABA) and an increase of protective proteins (dehydrin WCS120). This response was faster and stronger in winter wheat, where it coincided with the downregulation of bioactive cytokinins and auxin as well as enhanced deactivation of gibberellins, indicating rapid suppression of growth. Next, the ethylene precursor aminocyclopropane carboxylic acid was quickly upregulated. After 3-7 days of cold exposure, plant adaptation to the low temperature was correlated with a decrease in ABA and elevation of growth-promoting hormones (cytokinins, auxin and gibberellins). The content of other stress hormones, i.e., salicylic acid and jasmonic acid, also began to increase. After prolonged cold exposure (21 days), a resistance phase occurred. The winter cultivar exhibited substantially enhanced FT, which was associated with a decline in bioactive cytokinins and auxin. The inability of the spring cultivar to further increase its FT was correlated with maintenance of a relatively higher cytokinin and auxin content, which was achieved during the acclimation period. Copyright © 2012 Elsevier GmbH. All rights reserved.

Phosphate Availability Alters Architecture and Causes Changes in Hormone Sensitivity in the Arabidopsis Root System1

PubMed Central

López-Bucio, José; Hernández-Abreu, Esmeralda; Sánchez-Calderón, Lenin; Nieto-Jacobo, María Fernanda; Simpson, June; Herrera-Estrella, Luis

2002-01-01

The postembryonic developmental program of the plant root system is plastic and allows changes in root architecture to adapt to environmental conditions such as water and nutrient availability. Among essential nutrients, phosphorus (P) often limits plant productivity because of its low mobility in soil. Therefore, the architecture of the root system may determine the capacity of the plant to acquire this nutrient. We studied the effect of P availability on the development of the root system in Arabidopsis. We found that at P-limiting conditions (<50 μm), the Arabidopsis root system undergoes major architectural changes in terms of lateral root number, lateral root density, and primary root length. Treatment with auxins and auxin antagonists indicate that these changes are related to an increase in auxin sensitivity in the roots of P-deprived Arabidopsis seedlings. It was also found that the axr1-3, axr2-1, and axr4-1 Arabidopsis mutants have normal responses to low P availability conditions, whereas the iaa28-1 mutant shows resistance to the stimulatory effects of low P on root hair and lateral root formation. Analysis of ethylene signaling mutants and treatments with 1-aminocyclopropane-1-carboxylic acid showed that ethylene does not promote lateral root formation under P deprivation. These results suggest that in Arabidopsis, auxin sensitivity may play a fundamental role in the modifications of root architecture by P availability. PMID:12011355

Cloning and expression of 1-aminocyclopropane-1-carboxylate oxidase cDNA induced by thidiazuron during somatic embryogenesis of alfalfa (Medicago sativa).

PubMed

Feng, Bi-Hong; Wu, Bei; Zhang, Chun-Rong; Huang, Xia; Chen, Yun-Feng; Huang, Xue-Lin

2012-01-15

Embryogenic callus (EC) induced from petioles of alfalfa (Medicago sativa L. cv. Jinnan) on B5h medium turned green, compact and non-embryogenic when the kinetin (KN) in the medium was replaced partially or completely by thidiazuron (TDZ). The application of CoCl₂, which is an inhibitor of 1-aminocyclopropane-1-carboxylate oxidase (ACO), counteracted the effect of TDZ. Ethylene has been shown to be involved in the modulation of TDZ-induced morphogenesis responses. However, very little is known about the genes involved in ethylene formation during somatic embryogenesis (SE). To investigate whether ethylene mediated by ACO is involved in the effect of TDZ on inhibition of embryogenic competence of the alfalfa callus. In this study we cloned full-length ACO cDNA from the alfalfa callus, named MsACO, and observed changes in this gene expression during callus formation and induction of SE under treatment with TDZ or TDZ plus CoCl₂. RNA blot analysis showed that during the EC subcultural period, the expression level of MsACO in EC was significantly increased on the 2nd day, rose to the highest level on the 8th day and remained at this high level until the 21st day. However, the ACO expression in the TDZ (0.93 μM)-treated callus was higher than in the EC especially on the 8th day. Moreover the ACO expression level increased with increasing TDZ concentration during the subcultural/maintenance period of the callus. It is worth noting that comparing the treatment with TDZ alone, the treatment with 0.93 μM TDZ plus 50 μM CoCl₂ reduced both of the ACO gene expressions and ACO activity in the treated callus. These results indicate that the effect of TDZ could be counteracted by CoCl₂ either on the ACO gene expression level or ACO activity. Thus, a TDZ inhibitory effect on embryogenic competence of alfalfa callus could be mediated by ACO gene expression. Crown Copyright © 2011. Published by Elsevier GmbH. All rights reserved.

Effects of berberine and cinnamic acid on palmitic acid-induced intracellular triglyceride accumulation in NIT-1 pancreatic β cells.

PubMed

Zhao, Li; Jiang, Shu-Jun; Lu, Fu-Er; Xu, Li-Jun; Zou, Xin; Wang, Kai-Fu; Dong, Hui

2016-07-01

To investigate the effects of berberine (BBR) and cinnamic acid (CA), the main active components in Jiaotai Pill (, JTP), on palmitic acid (PA)-induced intracellular triglyceride (TG) accumulation in NIT-1 pancreatic β cells. Cells were incubated in culture medium containing PA (0.25 mmol/L) for 24 h. Then treatments with BBR (10 μmol/L), CA (100 μmol/L) and the combination of BBR and CA (BBR+CA) were performed respectively. Intracellular lipid accumulation was assessed by Oil Red O staining and TG content was measured by colorimetric assay. The expression of adenosine monophosphate-activated protein kinase (AMPK) protein and its downstream lipogenic and fatty acid oxidation genes, including fatty acid synthase (FAS), acetyl-coA carboxylase (ACC), phosphorylation acetyl-coA carboxylase (pACC), carnitine acyl transferase 1 (CPT-1) and sterol regulating element binding protein 1c (SREBP-1c) were determined by Western blot or real time polymerase chain reaction. PA induced an obvious lipid accumulation and a significant increase in intracellular TG content in NIT-1 cells. PA also induced a remarkable decrease in AMPK protein expression and its downstream targets such as pACC and CPT-1. Meanwhile, AMPK downstream lipogenic genes including SREBP-1c mRNA, FAS and ACC protein expressions were increased. Treatments with BBR and BBR+CA, superior to CA, significantly reversed the above genes changes in NIT-1 pancreatic β cells. However, the synergistic effect of BBR and CA on intracellular TG content was not observed in the present study. It can be concluded that in vitro, BBR and BBR+CA could inhibit PA-induced lipid accumulation by decreasing lipogenesis and increasing lipid oxidation in NIT-1 pancreatic β cells.

Biomineralisation by earthworms - an investigation into the stability and distribution of amorphous calcium carbonate.

PubMed

Hodson, Mark E; Benning, Liane G; Demarchi, Bea; Penkman, Kirsty E H; Rodriguez-Blanco, Juan D; Schofield, Paul F; Versteegh, Emma A A

Many biominerals form from amorphous calcium carbonate (ACC), but this phase is highly unstable when synthesised in its pure form inorganically. Several species of earthworm secrete calcium carbonate granules which contain highly stable ACC. We analysed the milky fluid from which granules form and solid granules for amino acid (by liquid chromatography) and functional group (by Fourier transform infrared (FTIR) spectroscopy) compositions. Granule elemental composition was determined using inductively coupled plasma-optical emission spectroscopy (ICP-OES) and electron microprobe analysis (EMPA). Mass of ACC present in solid granules was quantified using FTIR and compared to granule elemental and amino acid compositions. Bulk analysis of granules was of powdered bulk material. Spatially resolved analysis was of thin sections of granules using synchrotron-based μ-FTIR and EMPA electron microprobe analysis. The milky fluid from which granules form is amino acid-rich (≤ 136 ± 3 nmol mg -1 (n = 3; ± std dev) per individual amino acid); the CaCO 3 phase present is ACC. Even four years after production, granules contain ACC. No correlation exists between mass of ACC present and granule elemental composition. Granule amino acid concentrations correlate well with ACC content (r ≥ 0.7, p ≤ 0.05) consistent with a role for amino acids (or the proteins they make up) in ACC stabilisation. Intra-granule variation in ACC (RSD = 16%) and amino acid concentration (RSD = 22-35%) was high for granules produced by the same earthworm. Maps of ACC distribution produced using synchrotron-based μ-FTIR mapping of granule thin sections and the relative intensity of the ν 2 : ν 4 peak ratio, cluster analysis and component regression using ACC and calcite standards showed similar spatial distributions of likely ACC-rich and calcite-rich areas. We could not identify organic peaks in the μ-FTIR spectra and thus could not determine whether ACC-rich domains also had relatively high amino acid concentrations. No correlation exists between ACC distribution and elemental concentrations determined by EMPA. ACC present in earthworm CaCO 3 granules is highly stable. Our results suggest a role for amino acids (or proteins) in this stability. We see no evidence for stabilisation of ACC by incorporation of inorganic components. Graphical abstractSynchrotron-based μ-FTIR mapping was used to determine the spatial distribution of amorphous calcium carbonate in earthworm-produced CaCO 3 granules.

Endophytic bacteria and their potential to enhance heavy metal phytoextraction.

PubMed

Rajkumar, Mani; Ae, Noriharu; Freitas, Helena

2009-09-01

Pollution of soils with heavy metals is becoming one of the most severe environmental and human health hazards. Due to its widespread contamination finding innovative ways to clean metal pollutant has become a priority in the remediation field. Phytoremediation, the use of plants for the restoration of environments contaminated with pollutants is a relatively new technology that is more benign than current engineering solutions to treat contaminated sites. Recently, the benefits of combining endophytic bacteria with plants for increased remediation of pollutants have been successfully tried for toxic metal removal from contaminated soils. Endophytic bacteria reside within plant hosts without causing disease symptoms. Further, the metal resistant endophytes are reported to be present in various hyperaccumulator plants growing on heavy metal contaminated soils and play an important role in successful survival and growth of plants. Moreover, the metal resistant endophytes are reported to promote plant growth by various mechanisms such as nitrogen fixation, solubilization of minerals, production of phytohormones, siderophores, utilization of 1-aminocyclopropane-1-carboxylic acid as a sole N source and transformation of nutrient elements. In this review we highlight the diversity and plant growth promoting features of metal resistant endophytic bacteria and discuss their potential in phytoextraction of heavy metals from contaminated soils.

Identification of differentially expressed genes related to aphid resistance in cucumber (Cucumis sativus L.)

PubMed Central

Liang, Danna; Liu, Min; Hu, Qijing; He, Min; Qi, Xiaohua; Xu, Qiang; Zhou, Fucai; Chen, Xuehao

2015-01-01

Cucumber, a very important vegetable crop worldwide, is easily damaged by pests. Aphids (Aphis gossypii Glover) are among the most serious pests in cucumber production and often cause severe loss of yield and make fruit quality get worse. Identifying genes that render cucumbers resistant to aphid-induced damage and breeding aphid-resistant cucumber varieties have become the most promising control strategies. In this study, a Illumina Genome Analyzer platform was applied to monitor changes in gene expression in the whole genome of the cucumber cultivar ‘EP6392’ which is resistant to aphids. Nine DGE libraries were constructed from infected and uninfected leaves. In total, 49 differentially expressed genes related to cucumber aphid resistance were screened during the treatment period. These genes are mainly associated with signal transduction, plant-pathogen interactions, flavonoid biosynthesis, amino acid metabolism and sugar metabolism pathways. Eight of the 49 genes may be associated with aphid resistance. Finally, expression of 9 randomly selected genes was evaluated by qRT-PCR to verify the results for the tag-mapped genes. With the exception of 1-aminocyclopropane-1-carboxylate oxidase homolog 6, the expression of the chosen genes was in agreement with the results of the tag-sequencing analysis patterns. PMID:25959296

Bioaccumulation of nickel by E. sativa and role of plant growth promoting rhizobacteria (PGPRs) under nickel stress.

PubMed

Kamran, Muhammad Aqeel; Eqani, Syed Ali Musstjab Akber Shah; Bibi, Sadia; Xu, Ren-Kou; Amna; Monis, Muhammad Farooq Hussain; Katsoyiannis, Athanasios; Bokhari, Habib; Chaudhary, Hassan Javed

2016-04-01

Phytoremediation potential of plants can be enhanced in association with microbes. Further, many plant growth-promoting rhizobacteria can improve growth under stress. The present study was conducted to investigate the effect of Pseudomonas putida (P. putida) on nickel (Ni) uptake and on growth of Eruca sativa (E. sativa). Three different levels of Ni (low; 150 ug/g, medium; 250 ug/g and high; 500 ug/g) were applied to the soil containing E. sativa seedlings, with or without P. putida. Ni-toxicity was measured by metamorphic parameters including shoot length, root length, biomass, chlorophyll and proline and Ni contents. Inoculation with P. putida increased 34% and 41% in root and shoot length and 38% and 24% in fresh, dry weight respectively, as compared to non-inoculated plants. Similarly, Ni uptake increased by up to 46% following P. putida inoculation as compared to non-inoculated plants. Indole acetic acid, siderophore and 1-aminocyclopropane-1-carboxylate deaminase (ACCD) activity in the growing media enhanced growth and Ni uptake in E. sativa. The present results offer insight on Plant Growth Promoting Rhizobacteria (PGPR), such as P. putida, for the potential to enhance the plant growth by inhibiting the adverse effects of Ni in E. sativa. Copyright © 2016 Elsevier Inc. All rights reserved.

Purple corn-associated rhizobacteria with potential for plant growth promotion.

PubMed

Castellano-Hinojosa, A; Pérez-Tapia, V; Bedmar, E J; Santillana, N

2018-05-01

Purple corn (Zea mays var. purple amylaceum) is a native variety of the Peruvian Andes, cultivated at 3000 m since the pre-Inca times without N fertilization. We aimed to isolate and identify native plant growth-promoting rhizobacteria (PGPR) for future microbial-based inoculants. Eighteen strains were isolated from the rhizosphere of purple corn plants grown without N fertilization in Ayacucho (Peru). The 16S rRNA gene clustered the 18 strains into nine groups that contained species of Bacillus, Stenotrophomonas, Achromobacter, Paenibacillus, Pseudomonas and Lysinibacillus. A representative strain from each group was selected and assayed for N 2 fixation, phosphate solubilization, indole acetic and siderophore production, 1-aminocyclopropane-1-carboxylic acid deaminase activity and biocontrol abilities. Inoculation of purple corn plants with single and combined strains selected after a principal component analysis caused significant increases in root and shoot dry weight, total C and N contents of the plants. PGPRs can support growth and crop production of purple corn in the Peruvian Andes and constitute the base for microbial-based inoculants. This study enlarges our knowledge on plant-microbial interactions in high altitude mountains and provides new applications for PGPR inoculation in purple amylaceum corn, which is part of the staple diet for the native Quechua communities. © 2018 The Society for Applied Microbiology.

Significance of diazotrophic plant growth-promoting Herbaspirillum sp. GW103 on phytoextraction of Pband Zn by Zea mays L.

PubMed

Praburaman, Loganathan; Park, Sung-Hee; Cho, Min; Lee, Kui-Jae; Ko, Jeong-Ae; Han, Sang-Sub; Lee, Sang-Hyun; Kamala-Kannan, Seralathan; Oh, Byung-Taek

2017-01-01

Microbe-assisted phytoremediation has been considered a promising measure for the remediation of heavy metal-polluted soil. The aim of this study was to assess the effect of diazotrophic plant growth-promoting Herbaspirillum sp. GW103 on growth and lead (Pb) and zinc (Zn) accumulation in Zea mays L. The strain GW103 exhibited plant growth-promoting traits such as indole-3-acetic acid, siderophores, and 1-aminocyclopropane-1-carboxylic deaminase. Treatment of Z. mays L. plants with GW103 significantly increased 19, 31, and 52% of plant biomass and 10, 50, and 126% of chlorophyll a contents in Pb, Zn, and Pb + Zn-amended soils, respectively. Similarly, the strain GW103 significantly increased Pb and Zn accumulation in shoots and roots of Z. mays L., which were 77 and 25% in Pb-amended soil, 42 and 73% in Zn-amended soil, and 27 and 84% in Pb + Zn-amended soil. Furthermore, addition of GW103 increased 8, 12, and 7% of total protein content, catalase, and superoxide dismutase levels, respectively, in Z. mays L. plants. The results pointed out that isolate GW103 could potentially reduce the phytotoxicity of metals and increase Pb and Zn accumulation in Z. mays L. plant.

The chloroplast-localized phospholipases D α4 and α5 regulate herbivore-induced direct and indirect defenses in rice.

PubMed

Qi, Jinfeng; Zhou, Guoxin; Yang, Lijuan; Erb, Matthias; Lu, Yanhua; Sun, Xiaoling; Cheng, Jiaan; Lou, Yonggen

2011-12-01

The oxylipin pathway is of central importance for plant defensive responses. Yet, the first step of the pathway, the liberation of linolenic acid following induction, is poorly understood. Phospholipases D (PLDs) have been hypothesized to mediate this process, but data from Arabidopsis (Arabidopsis thaliana) regarding the role of PLDs in plant resistance have remained controversial. Here, we cloned two chloroplast-localized PLD genes from rice (Oryza sativa), OsPLDα4 and OsPLDα5, both of which were up-regulated in response to feeding by the rice striped stem borer (SSB) Chilo suppressalis, mechanical wounding, and treatment with jasmonic acid (JA). Antisense expression of OsPLDα4 and -α5 (as-pld), which resulted in a 50% reduction of the expression of the two genes, reduced elicited levels of linolenic acid, JA, green leaf volatiles, and ethylene and attenuated the SSB-induced expression of a mitogen-activated protein kinase (OsMPK3), a lipoxygenase (OsHI-LOX), a hydroperoxide lyase (OsHPL3), as well as a 1-aminocyclopropane-1-carboxylic acid synthase (OsACS2). The impaired oxylipin and ethylene signaling in as-pld plants decreased the levels of herbivore-induced trypsin protease inhibitors and volatiles, improved the performance of SSB and the rice brown planthopper Nilaparvata lugens, and reduced the attractiveness of plants to a larval parasitoid of SSB, Apanteles chilonis. The production of trypsin protease inhibitors in as-pld plants could be partially restored by JA, while the resistance to rice brown planthopper and SSB was restored by green leaf volatile application. Our results show that phospholipases function as important components of herbivore-induced direct and indirect defenses in rice.

Rhizosphere colonization and arsenic translocation in sunflower (Helianthus annuus L.) by arsenate reducing Alcaligenes sp. strain Dhal-L.

PubMed

Cavalca, Lucia; Corsini, Anna; Bachate, Sachin Prabhakar; Andreoni, Vincenza

2013-10-01

In the present study, six arsenic-resistant strains previously isolated were tested for their plant growth promoting characteristics and heavy metal resistance, in order to choose one model strain as an inoculum for sunflower plants in pot experiments. The aim was to investigate the effect of arsenic-resistant strain on sunflower growth and on arsenic uptake from arsenic contaminated soil. Based on plant growth promoting characteristics and heavy metal resistance, Alcaligenes sp. strain Dhal-L was chosen as an inoculum. Beside the ability to reduce arsenate to arsenite via an Ars operon, the strain exhibited 1-amino-cyclopropane-1-carboxylic acid deaminase activity and it was also able to produce siderophore and indole acetic acid. Pot experiments were conducted with an agricultural soil contaminated with arsenic (214 mg kg⁻¹). A real time PCR method was set up based on the quantification of ACR3(2) type of arsenite efflux pump carried by Alcaligenes sp. strain Dhal-L, in order to monitor presence and colonisation of the strain in the bulk and rhizospheric soil. As a result of strain inoculation, arsenic uptake by plants was increased by 53 %, whereas ACR3(2) gene copy number in rhizospheric soil was 100 times higher in inoculated than in control pots, indicating the colonisation of strain. The results indicated that the presence of arsenate reducing strains in the rhizosphere of sunflower influences arsenic mobilization and promotes arsenic uptake by plant.

Modification of the Host Cell Lipid Metabolism Induced by Hypolipidemic Drugs Targeting the Acetyl Coenzyme A Carboxylase Impairs West Nile Virus Replication

PubMed Central

Merino-Ramos, Teresa; Vázquez-Calvo, Ángela; Casas, Josefina; Sobrino, Francisco; Saiz, Juan-Carlos

2015-01-01

West Nile virus (WNV) is a neurotropic flavivirus transmitted by the bite of mosquitoes that causes meningitis and encephalitis in humans, horses, and birds. Several studies have highlighted that flavivirus infection is highly dependent on cellular lipids for virus replication and infectious particle biogenesis. The first steps of lipid synthesis involve the carboxylation of acetyl coenzyme A (acetyl-CoA) to malonyl-CoA that is catalyzed by the acetyl-CoA carboxylase (ACC). This makes ACC a key enzyme of lipid synthesis that is currently being evaluated as a therapeutic target for different disorders, including cancers, obesity, diabetes, and viral infections. We have analyzed the effect of the ACC inhibitor 5-(tetradecyloxy)-2-furoic acid (TOFA) on infection by WNV. Lipidomic analysis of TOFA-treated cells confirmed that this drug reduced the cellular content of multiple lipids, including those directly implicated in the flavivirus life cycle (glycerophospholipids, sphingolipids, and cholesterol). Treatment with TOFA significantly inhibited the multiplication of WNV in a dose-dependent manner. Further analysis of the antiviral effect of this drug showed that the inhibitory effect was related to a reduction of viral replication. Furthermore, treatment with another ACC inhibitor, 3,3,14,14-tetramethylhexadecanedioic acid (MEDICA 16), also inhibited WNV infection. Interestingly, TOFA and MEDICA 16 also reduced the multiplication of Usutu virus (USUV), a WNV-related flavivirus. These results point to the ACC as a druggable cellular target suitable for antiviral development against WNV and other flaviviruses. PMID:26503654

Modification of the Host Cell Lipid Metabolism Induced by Hypolipidemic Drugs Targeting the Acetyl Coenzyme A Carboxylase Impairs West Nile Virus Replication.

PubMed

Merino-Ramos, Teresa; Vázquez-Calvo, Ángela; Casas, Josefina; Sobrino, Francisco; Saiz, Juan-Carlos; Martín-Acebes, Miguel A

2016-01-01

West Nile virus (WNV) is a neurotropic flavivirus transmitted by the bite of mosquitoes that causes meningitis and encephalitis in humans, horses, and birds. Several studies have highlighted that flavivirus infection is highly dependent on cellular lipids for virus replication and infectious particle biogenesis. The first steps of lipid synthesis involve the carboxylation of acetyl coenzyme A (acetyl-CoA) to malonyl-CoA that is catalyzed by the acetyl-CoA carboxylase (ACC). This makes ACC a key enzyme of lipid synthesis that is currently being evaluated as a therapeutic target for different disorders, including cancers, obesity, diabetes, and viral infections. We have analyzed the effect of the ACC inhibitor 5-(tetradecyloxy)-2-furoic acid (TOFA) on infection by WNV. Lipidomic analysis of TOFA-treated cells confirmed that this drug reduced the cellular content of multiple lipids, including those directly implicated in the flavivirus life cycle (glycerophospholipids, sphingolipids, and cholesterol). Treatment with TOFA significantly inhibited the multiplication of WNV in a dose-dependent manner. Further analysis of the antiviral effect of this drug showed that the inhibitory effect was related to a reduction of viral replication. Furthermore, treatment with another ACC inhibitor, 3,3,14,14-tetramethylhexadecanedioic acid (MEDICA 16), also inhibited WNV infection. Interestingly, TOFA and MEDICA 16 also reduced the multiplication of Usutu virus (USUV), a WNV-related flavivirus. These results point to the ACC as a druggable cellular target suitable for antiviral development against WNV and other flaviviruses. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Preferential deprotonation and conformational stability of dicarboxylic acids: A packing effect

NASA Astrophysics Data System (ADS)

Barooah, Nilotpal; Singh, W. Marjit; Baruah, Jubaraj B.

2008-03-01

Crystal structures of a series of salts of (6-carboxymethyl-1,3,5,7-tetraoxo-3,5,6,7-tetrahydro-1 H-pyrrolo[3,4- f]isoindol-2-yl)-acetic acid ( 1) and 2-carboxymethyl-1,3-dioxo-2,3-dihydro-1 H-isoinodole-5-carboxylic acid ( 2) with different polynuclear nitrogen containing heterocyclic compounds, namely, quinoline, 1,10-phenanthroline and 8-hydroxyquinoline are determined. In the case of salt of 1 with quinolinium and 1,10-phenanthrolinium cations syn disposition between the carboxylate anion and carboxylic acid groups is observed; whereas in the case of the 8-hydroxyquinolinium salt of 1, it is the anti disposition. It is also found that the solid state structure of 1,10-phenanthrolinium salt of 2 has deprotonation at the aromatic end, whereas in 8-hydroxy-quinolinium salt of 2 is formed by deprotonation of carboxylic acid group on the aliphatic side. The dicarboxylic acid 2 forms 1:2 co-crystals with quinoline. From crystallographic study it is shown that the weak interactions become prominent in stabilising the observed conformers and also in stabilising specific deprotonated species.

Enhancement of Cd phytoextraction by two Amaranthus species with endophytic Rahnella sp. JN27.

PubMed

Yuan, Ming; He, Huaidong; Xiao, Li; Zhong, Ting; Liu, Hui; Li, Shubin; Deng, Peiyan; Ye, Zhihong; Jing, Yuanxiao

2014-05-01

Microbe-assisted phytoextraction shows a potential for the remediation of metal-contaminated soils. The aim of this study was to isolate, characterize, and evaluate the potential of endophytic bacteria in improving plant growth and metal uptake by Cd-hyperaccumulators-Amaranthus hypochondriacus and Amaranthus mangostanus. An endophytic bacterial strain JN27 isolated from roots of Zea mays displayed high tolerance and mobilization to Cd, and was identified as Rahnella sp. based on 16S rDNA sequencing. The strain also exhibited multiple plant growth beneficial features including the production of indole-3-acetic acid, siderophore, 1-aminocyclopropane-1-carboxylic acid deaminase and solubilization of insoluble phosphate. Subsequently, a pot trial was performed to elucidate the effects of inoculation with JN27 on plant growth and Cd uptake by A. hypochondriacus, A. mangostanus, Solanum nigrum and Z. mays grown in soils with different levels of Cd (25, 50, 100 mg Cd kg(-1)). The results revealed that inoculation with JN27 significantly increased the biomasses of all the tested plants and the Cd concentrations of all the tested plants except Z. mays in both above-ground and root tissues. Moreover, strain JN27 could successfully re-colonized in rhizosphere soils of all the tested plants and root interior of A. hypochondriacus and Z. mays. The present results indicated that the symbiont of A. hypochondriacus (or A. mangostanus) and strain JN27 can effectively improve the Cd uptake by plants and would be a new strategy in microbe-assisted phytoextraction for metal-contaminated soils. Copyright © 2013 Elsevier Ltd. All rights reserved.

Carboxylic acid accelerated formation of diesters

DOEpatents

Tustin, Gerald Charles; Dickson, Todd Jay

1998-01-01

This invention pertains to accelerating the rate of formation of 1,1-dicarboxylic esters from the reaction of an aldehyde with a carboxylic acid anhydride or a ketene in the presence of a non-iodide containing a strong Bronsted acid catalyst by the addition of a carboxylic acid at about one bar pressure and between about 0.degree. and 80.degree. C. in the substantial absence of a hydrogenation or carbonylation catalyst.

Carboxylic acid accelerated formation of diesters

DOEpatents

Tustin, G.C.; Dickson, T.J.

1998-04-28

This invention pertains to accelerating the rate of formation of 1,1-dicarboxylic esters from the reaction of an aldehyde with a carboxylic acid anhydride or a ketene in the presence of a non-iodide containing a strong Bronsted acid catalyst by the addition of a carboxylic acid at about one bar pressure and between about 0 and 80 C in the substantial absence of a hydrogenation or carbonylation catalyst.

DETERMINATION OF CARBOXYLIC ACIDS BY ION-EXCLUSION CHROMATOGRAPHY WITH NON-SUPPRESSED CONDUCTIVITY AND OPTICAL DETECTORS

EPA Science Inventory

Determination of carboxylic acids using non-suppressed conductivity and UV detections is described. The background conductance of 1-octanesulfonic acid, hexane sulfonic acid and sulfuric acid at varying concentrations was determined. Using 0.2 mM 1-octanesulfonic acid as a mobile...

Biocontrol and plant growth-promoting activity of rhizobacteria from Chinese fields with contaminated soils

PubMed Central

Wang, Xuefei; Mavrodi, Dmitri V; Ke, Linfeng; Mavrodi, Olga V; Yang, Mingming; Thomashow, Linda S; Zheng, Na; Weller, David M; Zhang, Jibin

2015-01-01

The aim of this study was to inventory the types of plant growth-promoting rhizobacteria (PGPR) present in the rhizosphere of plants grown in soils contaminated with heavy metals, recalcitrant organics, petroleum sewage or salinity in China. We screened 1223 isolates for antifungal activity and about 24% inhibited Rhizoctonia solani or Sclerotinia sclerotiorum. Twenty-four strains inhibitory to R. solani, Gaeumannomyces graminis var. tritici and/or S. sclerotiorum and representing the dominant morphotypes were assayed for PGPR activity. Seven strains contained phlD, prnD, pltC or phzF genes and produced the antibiotics 2,4-diacetylphloroglucinol, pyrrolnitrin, pyoluteorin and phenazines respectively. Six strains contained acdS, which encodes 1-aminocyclopropane-1-carboxylic acid deaminase. Phylogenetic analysis of 16S rDNA and phlD, phzF and acdS genes demonstrated that some strains identified as Pseudomonas were similar to model PGPR strains Pseudomonas protegens Pf-5, Pseudomonas chlororaphis subsp. aureofaciens 30–84 and P. brassicacearum Q8r1-96. Pseudomonas protegens- and P. chlororaphis-like strains had the greatest biocontrol activity against Rhizoctonia root rot and take-all of wheat. Pseudomonas protegens and P. brassicacearum-like strains showed the greatest promotion of canola growth. Our results indicate that strains from contaminated soils are similar to well-described PGPR found in agricultural soils worldwide. Growth-promoting rhizobacteria in polluted soils PMID:25219642

Multifarious beneficial traits and plant growth promoting potential of Serratia marcescens KiSII and Enterobacter sp. RNF 267 isolated from the rhizosphere of coconut palms (Cocos nucifera L.).

PubMed

George, Priya; Gupta, Alka; Gopal, Murali; Thomas, Litty; Thomas, George V

2013-01-01

Two plant growth promoting bacteria designated as KiSII and RNF 267 isolated from the rhizosphere of coconut palms were identified as Serratia marcescens and Enterobacter sp. based on their phenotypic features, BIOLOG studies and 16S rRNA gene sequence analysis. Both bacteria exhibited phosphate solubilization, ammonification, and production of indole acetic acid, β-1, 3 glucanase activities and 1-aminocyclopropane-1-carboxylate-deaminase activity. They could also tolerate a range of pH conditions, low temperature and salinity (NaCl). In addition, S. marcescens KiSII exhibited N- fixation potential, chitinase activity, siderophore production and antibiotics production. Seed bacterization with these bacteria increased the growth parameters of test plants such as paddy and cowpea over uninoculated control in green house assay. In coconut seedlings, significant increase in growth and nutrient uptake accompanied with higher populations of plant beneficial microorganisms in their rhizospheres were recorded on inoculation with both the PGPRs. The present study clearly revealed that PGPRs can aid in production of healthy and vigorous seedlings of coconut palm which are hardy perennial crops. They offer a scope to be developed into novel PGPR based bioinoculants for production of elite seedlings that can benefit the coconut farming community and the coconut based ecology.

Methylobacterium phyllosphaerae sp. nov., a pink-pigmented, facultative methylotroph from the phyllosphere of rice.

PubMed

Madhaiyan, Munusamy; Poonguzhali, Selvaraj; Kwon, Soon-Wo; Sa, Tong-Min

2009-01-01

A pink-pigmented, aerobic, facultatively methylotrophic bacterial strain, CBMB27T, isolated from leaf tissues of rice (Oryza sativa L. 'Dong-Jin'), was analysed using a polyphasic taxonomic approach. Comparative 16S rRNA gene sequence-based phylogenetic analysis placed the strain in a clade with the species Methylobacterium oryzae, Methylobacterium fujisawaense and Methylobacterium mesophilicum; strain CBMB27T showed sequence similarities of 98.3, 98.5 and 97.3 %, respectively, to the type strains of these three species. DNA-DNA hybridization experiments revealed low levels (<38 %) of DNA-DNA relatedness between strain CBMB27T and its closest relatives. The sequence of the 1-aminocyclopropane-1-carboxylate deaminase gene (acdS) in strain CBMB27T differed from those of close relatives. The major fatty acid of the isolate was C(18 : 1)omega7c and the G+C content of the genomic DNA was 66.8 mol%. Based on the results of 16S rRNA gene sequence analysis, DNA-DNA hybridization, and physiological and biochemical characterization, which enabled the isolate to be differentiated from all recognized species of the genus Methylobacterium, it was concluded that strain CBMB27T represents a novel species in the genus Methylobacterium for which the name Methylobacterium phyllosphaerae sp. nov. is proposed (type strain CBMB27T =LMG 24361T =KACC 11716T =DSM 19779T).

Short-term complete submergence of rice at the tillering stage increases yield.

PubMed

Zhang, Yajie; Wang, Zhensheng; Li, Lei; Zhou, Qun; Xiao, Yao; Wei, Xing; Zhou, Mingyao

2015-01-01

Flooding is a major threat to agricultural production. Most studies have focused on the lower water storage limit in rice fields, whereas few studies have examined the upper water storage limit. This study aimed to explore the effect of waterlogging at the rice tillering stage on rice growth and yield. The early-ripening late japonica variety Yangjing 4227 was selected for this study. The treatments included different submergence depths (submergence depth/plant height: 1/2 (waist submergence), 2/3 (neck submergence), and 1/1 (complete submergence)) and durations (1, 3, and 5 d). The control group was treated with the conventional alternation of drying and wetting. The effects of waterlogging at the tillering stage on root characteristics, dry matter production, nitrogen and phosphorus accumulation, yield, yield components, and 1-aminocyclopropane-1-carboxylic acid synthase (ACS) gene expression were explored. Compared with the control group, the 1/1 group showed significant increases in yield, seed-setting rate, photosynthetically efficient leaf area, and OS-ACS3 gene expression after 1 d of submergence. The grain number per panicle, dry weight of the aboveground and belowground parts, and number of adventitious roots also increased. Correlation analysis revealed a significant positive correlation between the panicle number and nitrogen content; however, no significant correlation was found for phosphorus content. If a decrease in rice yield of less than 10% is acceptable, half, 2/3, and complete submergence of the plants can be performed at the tillering stage for 1-3 d; this treatment will increase the space available for rice field water management/control and will improve rainfall resource utilization.

Endogenous factors regulating poor-nutrition stress-induced flowering in pharbitis: The involvement of metabolic pathways regulated by aminooxyacetic acid.

PubMed

Koshio, Aya; Hasegawa, Tomomi; Okada, Rieko; Takeno, Kiyotoshi

2015-01-15

The short-day plant pharbitis (also called Japanese morning glory), Ipomoea nil (formerly Pharbitis nil), was induced to flower by poor-nutrition stress. This stress-induced flowering was inhibited by aminooxyacetic acid (AOA), which is a known inhibitor of phenylalanine ammonia-lyase (PAL) and the synthesis of indole-3-acetic acid (IAA) and 1-aminocycropropane-1-carboxylic acid (ACC) and thus regulates endogenous levels of salicylic acid (SA), IAA and polyamine (PA). Stress treatment increased PAL activity in cotyledons, and AOA suppressed this increase. The observed PAL activity and flowering response correlate positively, indicating that AOA functions as a PAL inhibitor. The inhibition of stress-induced flowering by AOA was also overcome by IAA. An antiauxin, 4-chlorophenoxy isobutyric acid, inhibited stress-induced flowering. Both SA and IAA promoted flowering induced by stress. PA also promoted flowering, and the effective PA was found to be putrescine (Put). These results suggest that all of the pathways leading to the synthesis of SA, IAA and Put are responsive to the flowering inhibition by AOA and that these endogenous factors may be involved in the regulation of stress-induced flowering. However, as none of them induced flowering under non-stress conditions, they may function cooperatively to promote flowering. Copyright © 2014 Elsevier GmbH. All rights reserved.

Separation of aromatic carboxylic acids using quaternary ammonium salts on reversed-phase HPLC. 1. Separation behavior of aromatic carboxylic acids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kawamura, K.; Okuwaki, A.; Verheyen, T.

In order to develop separation processes and analytical methods for aromatic carboxylic acids for the coal oxidation products, the separation behavior of aromatic carboxylic acids on a reversed-phase HPLC using eluent containing quaternary ammonium salt has been investigated. The retention mechanism of aromatic carboxylic acids was discussed on the basis of both ion-pair partition model and ion-exchange model. The retention behavior of aromatic carboxylic acids possessing one (or two) carboxylic acid group(s) followed the ion-pair partition model, where linear free energy relationship was observed between the capacity factor and the extraction equilibrium constants of benzoic acid and naphthalene carboxylic acid.more » Besides, the retention behavior followed ion-exchange model with increasing the number of carboxylic acids, where the capacity factor of benzene polycarboxylic acids is proportional to the association constants between aromatic acids and quaternary ammonium ions calculated on the basis of an electrostatic interaction model.« less

Volatile-Mediated Effects Predominate in Paraburkholderia phytofirmans Growth Promotion and Salt Stress Tolerance of Arabidopsis thaliana

PubMed Central

Ledger, Thomas; Rojas, Sandy; Timmermann, Tania; Pinedo, Ignacio; Poupin, María J.; Garrido, Tatiana; Richter, Pablo; Tamayo, Javier

2016-01-01

Abiotic stress has a growing impact on plant growth and agricultural activity worldwide. Specific plant growth promoting rhizobacteria have been reported to stimulate growth and tolerance to abiotic stress in plants, and molecular mechanisms like phytohormone synthesis and 1-aminocyclopropane-1-carboxylate deamination are usual candidates proposed to mediate these bacterial effects. Paraburkholderia phytofirmans PsJN is able to promote growth of several plant hosts, and improve their tolerance to chilling, drought and salinity. This work investigated bacterial determinants involved in PsJN stimulation of growth and salinity tolerance in Arabidopsis thaliana, showing bacteria enable plants to survive long-term salinity treatment, accumulating less sodium within leaf tissues relative to non-inoculated controls. Inactivation of specific bacterial genes encoding ACC deaminase, auxin catabolism, N-acyl-homoserine-lactone production, and flagellin synthesis showed these functions have little influence on bacterial induction of salinity tolerance. Volatile organic compound emission from strain PsJN was shown to reproduce the effects of direct bacterial inoculation of roots, increasing plant growth rate and tolerance to salinity evaluated both in vitro and in soil. Furthermore, early exposure to VOCs from P. phytofirmans was sufficient to stimulate long-term effects observed in Arabidopsis growth in the presence and absence of salinity. Organic compounds were analyzed in the headspace of PsJN cultures, showing production of 2-undecanone, 7-hexanol, 3-methylbutanol and dimethyl disulfide. Exposure of A. thaliana to different quantities of these molecules showed that they are able to influence growth in a wide range of added amounts. Exposure to a blend of the first three compounds was found to mimic the effects of PsJN on both general growth promotion and salinity tolerance. To our knowledge, this is the first report on volatile compound-mediated induction of plant abiotic stress tolerance by a Paraburkholderia species. PMID:27909432

6-Substituted 3,4-dihydro-naphthalene-2-carboxylic acids: synthesis and structure-activity studies in a novel class of human 5alpha reductase inhibitors.

PubMed

Baston, Eckhard; Salem, Ola I A; Hartmann, Rolf W

2002-10-01

Novel 3,4-dihydro-naphthalene-2-carboxylic acids were synthesized and evaluated for 5alpha reductase inhibitory activity. This enzyme exists in two isoforms and is a pharmacological target for the treatment of benign prostatic hyperplasia, male pattern baldness and acne. In the present study non-steroidal compounds capable of mimicking the transition state of the steroidal substrates were prepared. The synthetic strategy for the preparation of compounds 1-6 consisted of triflation followed by subsequent Heck-type carboxylation or methoxy carbonylation for 6-phenyl-3,4-dihydronaphthalen-2(1H)-one 1c. A Negishi-type coupling reaction between 6-(trifluoro-methanesulfonyloxy)-3,4-dihydro-naphthalene-2-carboxylic acid methyl ester 7b and various aryl bromides led, after further transformations, to 6-substituted 3,4-dihydro-naphthalene-2-carboxylic acids 7-15. In a similar way the corresponding naphthalene-2-carboxylic acids 16 and 17 were obtained. The DU 145 cell line and prostate homogenates served as enzyme sources for the human type 1 and type 2 isozymes, whereas ventral prostate was employed to evaluate rat isozyme inhibitory potency. The most active inhibitors identified in this study were 6-[4-(N,N-dicyclohexylaminocarbonyl)phenyl]-3,4-dihydro-naphthalene-2-carboxylic acid (3) (IC50 = 0.09 microM, rat type 1), 6-[3-(N,N-dicyclohexylaminocarbonyl)phenyl]-3,4-dihydro-naphthalene-2-carboxylic acid (13) (IC50 = 0.75 microM, human type 2; IC50 = 0.81 microM, human type 1) and 6-[4-(N,N-diisopropylamino-carbonyl)phenyl]naphthalene-2-carboxylic acid (16) (IC50 = 0.2 microM, human type 2). The latter compound was shown to deactivate the enzyme in an uncompetitive manner (Ki = 90 nM; Km, Testosterone = 0.8-1.0 microM) similar to the steroidal inhibitor Epristeride. Select inhibitors (13 and 16) were tested in vivo using testosterone propionate-treated, juvenile, orchiectomized SD-rats. None of the compounds was active at a dose of 25 mg/kg. This result might in part be ascribed to the relatively poor in vitro rat isozyme inhibitory potency.

A chromene and prenylated benzoic acid from Piper aduncum.

PubMed

Baldoqui, D C; Kato, M J; Cavalheiro, A J; Bolzani, V da S; Young, M C; Furlan, M

1999-08-01

In addition to nerolidol, 2',6'-dihydroxy-4'-methoxydihydrochalcone, methyl 2,2-dimethyl-8-(3'-methyl-2'-butenyl)-2H-1-chromene-6-carboxylate, methyl 2,2-dimethyl-2H-1-chromene-6-carboxylate and methyl 8-hydroxy-2,2-dimethyl-2H-1-chromene-6-carboxylate, two new natural products were isolated from the leaves of Piper aduncum, 2,2-dimethyl-2H-1-chromene-6-carboxylic acid and 3-(3',7'-dimethyl-2',6'-octadienyl)-4-methoxybenzoic acid. The structures of the isolates were established based on analysis of spectroscopic data, including ES-MS. The DNA-damaging activity of the isolated compounds was also investigated against mutant strains of Saccharomyces cerevisiae.

Surface Patterning of Benzene Carboxylic Acids on Graphite: Influence of structure, solvent, and concentration on molecular self-assembly

NASA Astrophysics Data System (ADS)

Florio, Gina; Stiso, Kimberly; Campanelli, Joseph; Dessources, Kimberly; Folkes, Trudi

2012-02-01

Scanning tunneling microscopy (STM) was used to investigate the molecular self-assembly of four different benzene carboxylic acid derivatives at the liquid/graphite interface: pyromellitic acid (1,2,4,5-benzenetetracarboxylic acid), trimellitic acid (1,2,4-benzenetricarboxylic acid), trimesic acid (1,3,5-benzenetricarboxylic acid), and 1,3,5-benzenetriacetic acid. A range of two dimensional networks are observed that depend sensitively on the number of carboxylic acids present, the nature of the solvent, and the solution concentration. We will describe our recent efforts to determine (a) the preferential two-dimensional structure(s) for each benzene carboxylic acid at the liquid/graphite interface, (b) the thermodynamic and kinetic factors influencing self-assembly (or lack thereof), (c) the role solvent plays in the assembly, (e) the effect of in situ versus ex situ dilution on surface packing density, and (f) the temporal evolution of the self-assembled monolayer. Results of computational analysis of analog molecules and model monolayer films will also be presented to aid assignment of network structures and to provide a qualitative picture of surface adsorption and network formation.

Acetyl-CoA Carboxylase Inhibition Reverses NAFLD and Hepatic Insulin Resistance but Promotes Hypertriglyceridemia in Rodents.

PubMed

Goedeke, Leigh; Bates, Jamie; Vatner, Daniel F; Perry, Rachel J; Wang, Ting; Ramirez, Ricardo; Li, Li; Ellis, Matthew W; Zhang, Dongyan; Wong, Kari E; Beysen, Carine; Cline, Gary W; Ray, Adrian S; Shulman, Gerald I

2018-05-23

Pharmacologic inhibition of acetyl-CoA carboxylase (ACC) enzymes, ACC1 and ACC2, offers an attractive therapeutic strategy for non-alcoholic fatty liver disease (NAFLD) via simultaneous inhibition of fatty acid synthesis and stimulation of fatty acid oxidation. However, the effects of ACC inhibition on hepatic mitochondrial oxidation, anaplerosis, and ketogenesis in vivo are unknown. Here, we evaluated the impact of a novel liver-directed allosteric inhibitor of ACC1 and ACC2 (Compound 1) on these parameters, as well as glucose and lipid metabolism, in control and diet-induced rodent models of NAFLD. Oral administration of Compound 1 preferentially inhibited ACC enzymatic activity in the liver, reduced hepatic malonyl-CoA levels and enhanced hepatic ketogenesis by 50%. Furthermore, administration for 6 days to high-fructose fed rats resulted in a 20% reduction in hepatic de novo lipogenesis. Importantly, long-term treatment (21 days) significantly reduced high-fat sucrose diet (HFSD)-induced hepatic steatosis, PKCε activation and hepatic insulin resistance. ACCi treatment was associated with a significant increase in plasma triglycerides (∼30 to 130%, depending on length of fasting). ACCi-mediated hypertriglyceridemia could be attributed to a ∼15% increase in hepatic VLDL production and ∼20% reduction in triglyceride clearance by lipoprotein lipase (LPL) (P ≤ 0.05). At the molecular level, these changes were associated with increases in LXR/SREBP1 and decreases in PPARα target activation and could be reversed with fenofibrate co-treatment in a high-fat diet mouse model. Collectively, these studies warrant further investigation into the therapeutic utility of liver-directed ACC inhibition for the treatment of NAFLD and hepatic insulin resistance. This article is protected by copyright. All rights reserved. © 2018 by the American Association for the Study of Liver Diseases.

AMPK activation represses the human gene promoter of the cardiac isoform of acetyl-CoA carboxylase: Role of nuclear respiratory factor-1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adam, Tasneem; Opie, Lionel H.; Essop, M. Faadiel, E-mail: mfessop@sun.ac.za

Research highlights: {yields} AMPK inhibits acetyl-CoA carboxylase beta gene promoter activity. {yields} Nuclear respiratory factor-1 inhibits acetyl-CoA carboxylase beta promoter activity. {yields} AMPK regulates acetyl-CoA carboxylase beta at transcriptional level. -- Abstract: The cardiac-enriched isoform of acetyl-CoA carboxylase (ACC{beta}) produces malonyl-CoA, a potent inhibitor of carnitine palmitoyltransferase-1. AMPK inhibits ACC{beta} activity, lowering malonyl-CoA levels and promoting mitochondrial fatty acid {beta}-oxidation. Previously, AMPK increased promoter binding of nuclear respiratory factor-1 (NRF-1), a pivotal transcriptional modulator controlling gene expression of mitochondrial proteins. We therefore hypothesized that NRF-1 inhibits myocardial ACC{beta} promoter activity via AMPK activation. A human ACC{beta} promoter-luciferase construct was transientlymore » transfected into neonatal cardiomyocytes {+-} a NRF-1 expression construct. NRF-1 overexpression decreased ACC{beta} gene promoter activity by 71 {+-} 4.6% (p < 0.001 vs. control). Transfections with 5'-end serial promoter deletions revealed that NRF-1-mediated repression of ACC{beta} was abolished with a pPII{beta}-18/+65-Luc deletion construct. AMPK activation dose-dependently reduced ACC{beta} promoter activity, while NRF-1 addition did not further decrease it. We also investigated NRF-1 inhibition in the presence of upstream stimulatory factor 1 (USF1), a known transactivator of the human ACC{beta} gene promoter. Here NRF-1 blunted USF1-dependent induction of ACC{beta} promoter activity by 58 {+-} 7.5% (p < 0.001 vs. control), reversed with a dominant negative NRF-1 construct. NRF-1 also suppressed endogenous USF1 transcriptional activity by 55 {+-} 6.2% (p < 0.001 vs. control). This study demonstrates that NRF-1 is a novel transcriptional inhibitor of the human ACC{beta} gene promoter in the mammalian heart. Our data extends AMPK regulation of ACC{beta} to the transcriptional level.« less

Conjugates of desferrioxamine B (DFOB) with derivatives of adamantane or with orally available chelators as potential agents for treating iron overload.

PubMed

Liu, Joe; Obando, Daniel; Schipanski, Liam G; Groebler, Ludwig K; Witting, Paul K; Kalinowski, Danuta S; Richardson, Des R; Codd, Rachel

2010-02-11

Desferrioxamine B (DFOB) conjugates with adamantane-1-carboxylic acid, 3-hydroxyadamantane-1-carboxylic acid, 3,5-dimethyladamantane-1-carboxylic acid, adamantane-1-acetic acid, 4-methylphenoxyacetic acid, 3-hydroxy-2-methyl-4-oxo-1-pyridineacetic acid (N-acetic acid derivative of deferiprone), or 4-[3,5-bis(2-hydroxyphenyl)-1,2,4-triazol-1-yl]benzoic acid (deferasirox) were prepared and the integrity of Fe(III) binding of the compounds was established from electrospray ionization mass spectrometry and RP-HPLC measurements. The extent of intracellular (59)Fe mobilized by the DFOB-3,5-dimethyladamantane-1-carboxylic acid adduct was 3-fold greater than DFOB alone, and the IC(50) value of this adduct was 6- or 15-fold greater than DFOB in two different cell types. The relationship between logP and (59)Fe mobilization for the DFOB conjugates showed that maximal mobilization of intracellular (59)Fe occurred at a logP value approximately 2.3. This parameter, rather than the affinity for Fe(III), appears to influence the extent of intracellular (59)Fe mobilization. The low toxicity-high Fe mobilization efficacy of selected adamantane-based DFOB conjugates underscores the potential of these compounds to treat iron overload disease in patients with transfusional-dependent disorders such as beta-thalassemia.

Translational control of human acetyl-CoA carboxylase 1 mRNA is mediated by an internal ribosome entry site in response to ER stress, serum deprivation or hypoxia mimetic CoCl2.

PubMed

Damiano, Fabrizio; Testini, Mariangela; Tocci, Romina; Gnoni, Gabriele V; Siculella, Luisa

2018-04-01

Acetyl-CoA carboxylase 1 (ACC1) is a cytosolic enzyme catalyzing the rate limiting step in de novo fatty acid biosynthesis. There is mounting evidence showing that ACC1 is susceptible to dysregulation and that it is over-expressed in liver diseases associated with lipid accumulation and in several cancers. In the present study, ACC1 regulation at the translational level is reported. Using several experimental approaches, the presence of an internal ribosome entry site (IRES) has been established in the 5' untranslated region (5' UTR) of the ACC1 mRNA. Transfection experiments with the ACC1 5' UTR inserted in a dicistronic reporter vector show a remarkable increase in the downstream cistron translation, through a cap-independent mechanism. The endoplasmic reticulum (ER) stress condition and the related unfolded protein response (UPR), triggered by treatment with thapsigargin and tunicamycin, cause an increase of the cap-independent translation of ACC1 mRNA in HepG2 cells, despite the overall reduction in global protein synthesis. Other stress conditions, such as serum starvation and incubation with hypoxia mimetic agent CoCl 2 , up-regulate ACC1 expression in HepG2 cells at the translational level. Overall, these findings indicate that the presence of an IRES in the ACC1 5' UTR allows ACC1 mRNA translation in conditions that are inhibitory to cap-dependent translation. A potential involvement of the cap-independent translation of ACC1 in several pathologies, such as obesity and cancer, has been discussed. Copyright © 2018 Elsevier B.V. All rights reserved.

Endophytic Bacteria Associated with Hieracium piloselloides: Their Potential for Hydrocarbon-Utilizing and Plant Growth-Promotion.

PubMed

Pawlik, Małgorzata; Piotrowska-Seget, Zofia

2015-01-01

The aim of this study was to assess the potential of 18 crude-oil-degrading endophytic bacteria for removal of hydrocarbons and promotion of plant growth. Strains were isolated from Hieracium piloselloides (tall hawkweed), which grows in soil heavily polluted with petroleum hydrocarbons. Bacteria from the genus Pseudomonas were abundant among the isolates. The potential for hydrocarbon degradation was evaluated by polymerase chain reaction (PCR) analyses of the genes alkB, alkH, C23O, P450, and pah. It was found that 88.89% of the endophytic bacteria contained gene-encoding polycyclic aromatic hydrocarbon (PAH) initial dioxygenase, 61% possessed the 2,3-catechol dioxygenase gene, and 39% of strains that were tested had the cytochrome P-450 hydroxylase gene. All isolates were capable of producing indole-3-acetic acid (1.8-76.4 μg/ml). Only 17% of them were able to produce siderophores, excrete cellulase, and solubilize phosphate. Hydrogen cyanide synthesis occurred in 33% of endophytic bacteria. The 1-aminocyclopropane-1-carboxylate deaminase activity in isolates that were screened was in the range of 2.6 to 74.1 μmol α-ketobutyrate/mg/h. This feature of the bacteria indicated that isolates may enhance the phytoremediation process. Data suggest that crude-oil-degrading endophytic bacteria possess potential to be promising candidates for enhancement of phytoremediation of hydrocarbon-contaminated soil. Further evaluation of these bacteria is needed in order to assess the role played in the degradation of petroleum hydrocarbons.

Ethylene Biosynthesis and Signaling Is Required for Rice Immune Response and Basal Resistance Against Magnaporthe oryzae Infection.

PubMed

Helliwell, Emily E; Wang, Qin; Yang, Yinong

2016-11-01

Recent studies have suggested that ethylene enhances host resistance to fungal pathogen Magnaporthe oryzae, the causal agent of rice blast disease. Among the six 1-aminocyclopropane-1-carboxylic acid synthase genes in rice, OsACS1 and OsACS2 are induced within 24 h of inoculation by M. oryzae. This induction occurs simultaneously with an increase in ethylene production that is noticeable 12 h postinoculation. The purpose of this study was to examine the dynamics of ethylene production and signaling in wild type and RNA interference-mediated suppression lines deficient in ethylene production (acs2) or signaling (eil1) after challenge with M. oryzae as well as fungal cell-wall elicitors. Ethylene-insensitive mutant lines show an attenuated basal defense response including lower basal expression of the genes encoding a chitin-binding receptor, pathogenesis-related (PR) proteins, and the enzymes involved in the synthesis of diterprenoid phytoalexins, a reduction on early hypersensitive response (HR)-like cell death, and reduced incidence of callose deposition. Ethylene-deficient mutants showed an intermediate phenotype, with a significant reduction in expression of defense-related genes and callose deposition, but only a slight reduction in HR-like cell death. As a result, all ethylene-insensitive mutants show increased susceptibility to M. oryzae, whereas the ethylene-deficient lines show a slight but less significant increase in disease severity. These results show that ethylene signaling and, to some extent, ethylene production are required for rice basal resistance against the blast fungus Magnaporthe oryzae.

Olfactory Sensitivity and Odor Structure-Activity Relationships for Aliphatic Carboxylic Acids in CD-1 Mice

PubMed Central

Can Güven, Selçuk; Laska, Matthias

2012-01-01

Using a conditioning paradigm, the olfactory sensitivity of CD-1 mice for a homologous series of aliphatic n-carboxylic acids (ethanoic acid to n-octanoic acid) and several of their isomeric forms was investigated. With all 14 odorants, the animals significantly discriminated concentrations as low as 0.03 ppm (parts per million) from the solvent, and with four odorants the best-scoring animals even detected concentrations as low as 3 ppt (parts per trillion). Analysis of odor structure-activity relationships showed that the correlation between olfactory detection thresholds of the mice for the unbranched carboxylic acids and carbon chain length can best be described as a U-shaped function with the lowest threshold values at n-butanoic acid. A significant positive correlation between olfactory detection thresholds and carbon chain length of the carboxylic acids with their branching next to the functional carboxyl group was found. In contrast, no such correlation was found for carboxylic acids with their branching at the distal end of the carbon chain relative to the functional carboxyl group. Finally, a significant correlation was found between olfactory detection thresholds and the position of the branching of the carboxylic acids. Across-species comparisons suggest that mice are more sensitive for short-chained (C2 to C4) aliphatic n-carboxylic acids than other mammalian species, but not for longer-chained ones (C5 to C8). Further comparisons suggest that odor structure-activity relationships are both substance class- and species-specific. PMID:22479594

Organotin(IV) carboxylates based on 2-(1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)acetic acid: Syntheses, crystal structures, luminescent properties and antitumor activities

NASA Astrophysics Data System (ADS)

Xiao, Xiao; Liang, Jingwen; Xie, Jingyi; Liu, Xin; Zhu, Dongsheng; Dong, Yuan

2017-10-01

Organotin carboxylates based on an amide carboxylic acid 2-(1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)acetic acid (HL): [(Bn2Sn)2O2L]2·2C6H6 (1) (Bn = benzyl group) and (Ph2Sn)(L)2 (2) were synthesized and characterized by elemental analysis, IR, 1H, 13C, 119Sn NMR spectroscopy and X-ray crystallography diffraction analysis. Complex 1 is dimeric carboxylate tetraorganodistannoxane and show a "ladder-like" molecular structure. Complex 2 is a dialkyltin carboxylate monomer possessing crystallographically imposed two-fold symmetry. Ligand in 1 and 2 adopts unidentate and bidentate coordination respectively. Both 1 and 2 form 1D, 2D and 3D supramolecular organizations in the solid state mediated through Csbnd H⋯O and π⋯π interactions which are discussed in detail. The luminescent properties and preliminary antitumor activities about this series of complexes were also studied.

New Drugs for Pretreatment of Organophosphonate Intoxication

DTIC Science & Technology

1990-02-20

amineHydrochlorides 40 1 -Phenylcyclohexane-l-carboxylic Acid 41 Dialkylaminoalkyl 1 -Phenylcycloalkane-l-carboxylate Hydrochlorides 41 3 -Formyl-4,5...cyclopropyl-CH2)- 3 -(Dimethylamino)propyl 1 -Phenylcyclopropane-l-carboxylate Hydrochloride (PRE-150). The recrystallized yield was 18.2 g (53...Arylcycloalkyl)methyl]amines 8 ct,a-Dialkylphenethylamines 9 Dialkylaminoalkyl 1 -Phenylcycloalkane-l-carboxylates 10 3 -Dialkylaminoalkyl-4,5

Ethylene Inhibits Root Elongation during Alkaline Stress through AUXIN1 and Associated Changes in Auxin Accumulation1

PubMed Central

Li, Juan; Xu, Heng-Hao; Liu, Wen-Cheng; Zhang, Xiao-Wei

2015-01-01

Soil alkalinity causes major reductions in yield and quality of crops worldwide. The plant root is the first organ sensing soil alkalinity, which results in shorter primary roots. However, the mechanism underlying alkaline stress-mediated inhibition of root elongation remains to be further elucidated. Here, we report that alkaline conditions inhibit primary root elongation of Arabidopsis (Arabidopsis thaliana) seedlings by reducing cell division potential in the meristem zones and that ethylene signaling affects this process. The ethylene perception antagonist silver (Ag+) alleviated the inhibition of root elongation by alkaline stress. Moreover, the ethylene signaling mutants ethylene response1-3 (etr1-3), ethylene insensitive2 (ein2), and ein3-1 showed less reduction in root length under alkaline conditions, indicating a reduced sensitivity to alkalinity. Ethylene biosynthesis also was found to play a role in alkaline stress-mediated root inhibition; the ethylene overproducer1-1 mutant, which overproduces ethylene because of increased stability of 1-AMINOCYCLOPROPANE-1-CARBOXYLIC ACID SYNTHASE5, was hypersensitive to alkaline stress. In addition, the ethylene biosynthesis inhibitor cobalt (Co2+) suppressed alkaline stress-mediated inhibition of root elongation. We further found that alkaline stress caused an increase in auxin levels by promoting expression of auxin biosynthesis-related genes, but the increase in auxin levels was reduced in the roots of the etr1-3 and ein3-1 mutants and in Ag+/Co2+-treated wild-type plants. Additional genetic and physiological data showed that AUXIN1 (AUX1) was involved in alkaline stress-mediated inhibition of root elongation. Taken together, our results reveal that ethylene modulates alkaline stress-mediated inhibition of root growth by increasing auxin accumulation by stimulating the expression of AUX1 and auxin biosynthesis-related genes. PMID:26109425

Structure and thermotropic phase behavior of sodium and potassium carboxylate ionomers

NASA Astrophysics Data System (ADS)

Mantsch, H. H.; Weng, S. F.; Yang, P. W.; Eysel, H. H.

1994-07-01

A molecular complex is formed between long-chain carboxylic acids and their alkali salts in a 1 : 1 mixture. These so-called "acid soaps" or carboxylate ionomers have multilamellar bilayer-type structures in solid state, which are retained in the presence of excess water, resembling the dispersions (gels) formed by typical two-chain amphiphiles, e.g. lipids. The special arrangement of hydrogen-bonded pairs of carboxylic acid and carboxylate groups into a unique "head-group" is supported by frequency shifts and partial or total disappearance of the characteristic vibrations of carboxylic acid dimers and of carboxylate groups. The existence of well-ordered hydrocarbon chains is demonstrated by the existence and polarization properties of the methylene rocking and wagging propagation modes. The gel to liquid-crystal phase transition of the hydrated acid soaps shows practically no cation dependence, unlike the corresponding phase transition in neutral soaps which varies considerably with the nature of the counterion. There is spectroscopic evidence to suggest a cooperative process that involves "melting" of the alkyl chains and disintegration of the hydrogen-bonded carboxylate—carboxylic acid complex, followed by a cation-dependent equilibrium that favors the formation of acid dimers at elevated temperatures and some form of hydrogen-bonded ion pair aggregates at intermediate temperatures.

A new alkaloid from Portulaca oleracea L. and its antiacetylcholinesterase activity.

PubMed

Xiu, Fen; Li, Xuetao; Zhang, Wenjie; He, Fan; Ying, Xixiang; Stien, Didier

2018-04-18

A new alkaloid, (10E, 12E)-9-ureidooctadeca-10, 12-dienoic acid, named oleraurea (1) and 10 known compounds, p-hydroxybenzaldehyde (2), p-hydroxybenzoic acid (3), p-hydroxyacetophenone (4), benzamide (5), (E)-p-coumaramide (6), (E)-ferulamide (7), soyalkaloid A (8), β-carboline-3-carboxylic acid (9), 2, 3, 4, 9-tetrahydro-1H-pyrido [3, 4-b] indole-3-carboxylic acid (10), (1S, 3S)-1-methyl-1, 2, 3, 4-tetrahydro-β-carboline-3-carboxylic acid (11) were obtained from Portulaca oleracea L., in which, compounds 4, 5, 8-11 were isolated from the plant for the first time. The structure of the compound 1 was identified using spectroscopic methods including 1D and 2D NMR, HR-ESI-TOF-MS. The compounds 1, 5-11 presented anticholinesterase activities, but the P. oleracea extract (POE) presented very low anticholinesterase activity.

Release of sunflower seed dormancy by cyanide: cross-talk with ethylene signalling pathway

PubMed Central

Oracz, Krystyna; El-Maarouf-Bouteau, Hayat; Bogatek, Renata; Bailly, Christophe

2008-01-01

Freshly harvested sunflower (Helianthus annuus L.) seeds are considered to be dormant because they fail to germinate at relatively low temperatures (10 °C). This dormancy results mainly from an embryo dormancy and disappears during dry storage. Although endogenous ethylene is known to be involved in sunflower seed alleviation of dormancy, little attention had been paid to the possible role of cyanide, which is produced by the conversion of 1-aminocyclopropane 1-carboxylic acid to ethylene, in this process. The aims of this work were to investigate whether exogenous cyanide could improve the germination of dormant sunflower seeds and to elucidate its putative mechanisms of action. Naked dormant seeds became able to germinate at 10 °C when they were incubated in the presence of 1 mM gaseous cyanide. Other respiratory inhibitors showed that this effect did not result from an activation of the pentose phosphate pathway or the cyanide-insensitive pathway. Cyanide stimulated germination of dormant seeds in the presence of inhibitors of ethylene biosynthesis, but its improving effect required functional ethylene receptors. It did not significantly affect ethylene production and the expression of genes involved in ethylene biosynthesis or in the first steps of ethylene signalling pathway. However, the expression of the transcription factor Ethylene Response Factor 1 (ERF1) was markedly stimulated in the presence of gaseous cyanide. It is proposed that the mode of action of cyanide in sunflower seed dormancy alleviation does not involve ethylene production and that ERF1 is a common component of the ethylene and cyanide signalling pathways. PMID:18448476

Fine mapping and candidate gene analysis of qFL-chr1, a fiber length QTL in cotton.

PubMed

Xu, Peng; Gao, Jin; Cao, Zhibin; Chee, Peng W; Guo, Qi; Xu, Zhenzhen; Paterson, Andrew H; Zhang, Xianggui; Shen, Xinlian

2017-06-01

A fiber length QTL, qFL-chr1, was fine mapped to a 0.9 cM interval of cotton chromosome 1. Two positional candidate genes showed positive correlation between gene expression level and fiber length. Prior analysis of a backcross-self mapping population derived from a cross between Gossypium hirsutum L. and G. barbadense L. revealed a QTL on chromosome 1 associated with increased fiber length (qFL-chr1), which was confirmed in three independent populations of near-isogenic introgression lines (NIILs). Here, a single NIIL, R01-40-08, was used to develop a large population segregating for the target region. Twenty-two PCR-based polymorphic markers used to genotype 1672 BC 4 F 2 plants identified 432 recombinants containing breakpoints in the target region. Substitution mapping using 141 informative recombinants narrowed the position of qFL-chr1 to a 1.0-cM interval between SSR markers MUSS084 and CIR018. To exclude possible effects of non-target introgressions on fiber length, different heterozygous BC 4 F 3 plants introgressed between SSR markers NAU3384 and CGR5144 were selected to develop sub-NILs. The qFL-chr1 was further mapped at 0.9-cM interval between MUSS422 and CIR018 by comparisons of sub-NIL phenotype, and increased fiber length by ~1 mm. The 2.38-Mb region between MUSS422 and CIR018 in G. barbadense contained 19 annotated genes. Expression levels of two of these genes, GOBAR07705 (encoding 1-aminocyclopropane-1-carboxylate synthase) and GOBAR25992 (encoding amino acid permease), were positively correlated with fiber length in a small F 2 population, supporting these genes as candidates for qFL-chr1.

Analysis of gene expression during the transition to climacteric phase in carnation flowers (Dianthus caryophyllus L.).

PubMed

In, Byung-Chun; Binder, Brad M; Falbel, Tanya G; Patterson, Sara E

2013-11-01

It has been generally thought that in ethylene-sensitive plants such as carnations, senescence proceeds irreversibly once the tissues have entered the climacteric phase. While pre-climacteric petal tissues have a lower sensitivity to ethylene, these tissues are converted to the climacteric phase at a critical point during flower development. In this study, it is demonstrated that the senescence process initiated by exogenous ethylene is reversible in carnation petals. Petals treated with ethylene for 12h showed sustained inrolling and senescence, while petals treated with ethylene for 10h showed inrolling followed by recovery from inrolling. Reverse transcription-PCR analysis revealed differential expression of genes involved in ethylene biosynthesis and ethylene signalling between 10h and 12h ethylene treatment. Ethylene treatment at or beyond 12h (threshold time) decreased the mRNA levels of the receptor genes (DcETR1, DcERS1, and DcERS2) and DcCTR genes, and increased the ethylene biosynthesis genes DcACS1 and DcACO1. In contrast, ethylene treatment under the threshold time caused a transient decrease in the receptor genes and DcCTR genes, and a transient increase in DcACS1 and DcACO1. Sustained DcACS1 accumulation is correlated with decreases in DcCTR genes and increase in DcEIL3 and indicates that tissues have entered the climacteric phase and that senescence proceeds irreversibly. Inhibition of ACS (1-aminocyclopropane-1-carboxylic acid synthase) prior to 12h ethylene exposure was not able to prevent reduction in transcripts of DcCTR genes, yet suppressed transcript of DcACS1 and DcACO1. This leads to the recovery from inrolling of the petals, indicating that DcACS1 may act as a signalling molecule in senescence of flowers.

Analysis of gene expression during the transition to climacteric phase in carnation flowers (Dianthus caryophyllus L.)

PubMed Central

Patterson, Sara E.

2013-01-01

It has been generally thought that in ethylene-sensitive plants such as carnations, senescence proceeds irreversibly once the tissues have entered the climacteric phase. While pre-climacteric petal tissues have a lower sensitivity to ethylene, these tissues are converted to the climacteric phase at a critical point during flower development. In this study, it is demonstrated that the senescence process initiated by exogenous ethylene is reversible in carnation petals. Petals treated with ethylene for 12h showed sustained inrolling and senescence, while petals treated with ethylene for 10h showed inrolling followed by recovery from inrolling. Reverse transcription–PCR analysis revealed differential expression of genes involved in ethylene biosynthesis and ethylene signalling between 10h and 12h ethylene treatment. Ethylene treatment at or beyond 12h (threshold time) decreased the mRNA levels of the receptor genes (DcETR1, DcERS1, and DcERS2) and DcCTR genes, and increased the ethylene biosynthesis genes DcACS1 and DcACO1. In contrast, ethylene treatment under the threshold time caused a transient decrease in the receptor genes and DcCTR genes, and a transient increase in DcACS1 and DcACO1. Sustained DcACS1 accumulation is correlated with decreases in DcCTR genes and increase in DcEIL3 and indicates that tissues have entered the climacteric phase and that senescence proceeds irreversibly. Inhibition of ACS (1-aminocyclopropane-1-carboxylic acid synthase) prior to 12h ethylene exposure was not able to prevent reduction in transcripts of DcCTR genes, yet suppressed transcript of DcACS1 and DcACO1. This leads to the recovery from inrolling of the petals, indicating that DcACS1 may act as a signalling molecule in senescence of flowers. PMID:24078672

Activity and structure of human acetyl-CoA carboxylase targeted by a specific inhibitor.

PubMed

Jang, SoRi; Gornicki, Piotr; Marjanovic, Jasmina; Bass, Ethan; Lurcotta, Toni; Rodriguez, Pedro; Austin, Jotham; Haselkorn, Robert

2018-05-17

We have studied a series of human acetyl CoA-carboxylase (ACC) 1 and ACC2 proteins with deletions and/or Ser to Ala substitutions of the known phosphorylation sites. In vitro dephosphorylation/phosphorylation experiments reveal a substantial level of phosphorylation of human ACCs produced in insect cells. Our results are consistent with AMPK phosphorylation of Ser 29, Ser 80 , Ser 1,201 and Ser 1,216 . Phosphorylation of the N-terminal regulatory domain decreases ACC1 activity, while phosphorylation of residues in the ACC central domain has no effect. Inhibition of the activity by phosphorylation is significantly more profound at citrate concentrations below 2 mM. Furthermore, deletion of the N-terminal domain facilitates structural changes induced by citrate, including conversion of ACC dimers to linear polymers. We have also identified ACC2 amino acid mutations affecting specific inhibition of the isozyme by compound CD-017-0191. They form two clusters separated by 60-90 Å: one located in the vicinity of the BC active site and the other one in the vicinity of the ACC1 phosphorylation sites in the central domain, suggesting a contribution of the interface of two ACC dimers in the polymer to the inhibitor binding site. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Neurotoxicity and reactive astrogliosis in the anterior cingulate cortex in acute ciguatera poisoning.

PubMed

Zhang, Xu; Cao, Bing; Wang, Jun; Liu, Jin; Tung, Vivian Oi Vian; Lam, Paul Kwan Sing; Chan, Leo Lai; Li, Ying

2013-06-01

Ciguatoxins (CTXs) cause long-term disturbance of cerebral functions. The primary mechanism of neurotoxicity is related to their interaction with voltage-gated sodium channels. However, until now, the neurological targets for CTXs in the brain of intact animals have not been described. In our study, 1 day following oral exposure to 0.26 ng/g of Pacific ciguatoxin 1 (P-CTX-1), we performed in vivo electrophysiological recordings in the rat anterior cingulate cortex (ACC) and identified the increase in spontaneous firings and enhanced responses to visceral noxious stimulation. Local field recordings characterized the P-CTX-1-induced synaptic potentiation and blockage of the induction of electrical stimulation-induced long-term potentiation in the medial thalamus (MT)-ACC pathway. Furthermore, intracerebroventricular administration of P-CTX-1 at doses of 1.0, 5.0, and 10 nM produced a dose-dependent increase in ACC neuronal firings and MT-ACC synaptic transmission. Further studies showed upregulated Na(+) channel expression in astrocytes under pathological conditions. We hypothesized that the astrocytes might have been activated in the ciguatera poisoning in vivo. Increases in glial fibrillary acid protein expression were detected in reactive astrocytes in the rat ACC. The activation of astroglia was further indicated by activation of the gap junction protein connexin 43 and upregulation of excitatory amino acid transporter 2 expression suggesting that glutamate was normally rapidly cleared from the synaptic cleft during acute ciguatera poisoning. However, neurotoxicity and reactive astrogliosis were not detected in the ACC after 7 days of P-CTX-1 exposure. The present results are the first characterization of P-CTX-1-invoked brain cortex neuronal excitotoxicity in vivo and supported the theme that neuron and astroglia signals might play roles in acute ciguatera poisoning.

Heterogeneous Coordination Environments in Lithium-Neutralized Ionomers Identified Using 1H and 7Li MAS NMR

PubMed Central

Alam, Todd M.; Jenkins, Janelle E.; Bolintineanu, Dan S.; Stevens, Mark J.; Frischknecht, Amalie L.; Buitrago, C. Francisco; Winey, Karen I.; Opper, Kathleen L.; Wagener, Kenneth B.

2012-01-01

The carboxylic acid proton and the lithium coordination environments for precise and random Li-neutralized polyethylene acrylic acid P(E-AA) ionomers were explored using high speed solid-state 1H and 7Li MAS NMR. While the 7Li NMR revealed only a single Li coordination environment, the chemical shift temperature variation was dependent on the precise or random nature of the P(E-AA) ionomer. The 1H MAS NMR revealed two different carboxylic acid proton environments in these materials. By utilizing 1H-7Li rotational echo double resonance (REDOR) MAS NMR experiments, it was demonstrated that the proton environments correspond to different average 1H-7Li distances, with the majority of the protonated carboxylic acids having a close through space contact with the Li. Molecular dynamics simulations suggest that the shortest 1H-7Li distance corresponds to un-neutralized carboxylic acids directly involved in the coordination environment of Li clusters. These solid-state NMR results show that heterogeneous structural motifs need to be included when developing descriptions of these ionomer materials.

Characterization of Cd-resistant Klebsiella michiganensis MCC3089 and its potential for rice seedling growth promotion under Cd stress.

PubMed

Mitra, Soumik; Pramanik, Krishnendu; Ghosh, Pallab Kumar; Soren, Tithi; Sarkar, Anumita; Dey, Ramendra Sundar; Pandey, Sanjeev; Maiti, Tushar Kanti

2018-05-01

Application of heavy metal resistant plant growth promoting rhizobacteria has an important role as they help to evade metal-induced toxicity in plants on one hand and enhance plant growth on the other. The present study is therefore focused on the characterization of a cadmium resistant bacterial strain isolated from heavy metal contaminated rhizospheric soil designated as S8. This S8 strain was selected in terms of cadmium resistance and plant growth promoting traits. Moreover, it also showed resistance to lead and arsenic to a considerable extent. The selected strain S8 was identified as Klebsiella michiganensis by modern approaches of bacterial taxonomy. The plant growth promoting traits exhibited by the strain include 1-aminocyclopropane-1-carboxylic acid deaminase activity (58.33 ng α-keto butyrate/mg protein/h), Indole-3-acetic acid production (671 μg/ml), phosphate solubilization (71.98 ppm), nitrogen fixation (3.72 μg of nitrogen fixed/h/mg protein) etc. Besides, the strain also exhibited high cadmium removal efficiency (73-97%) from the medium and intracellular accumulation as well. Its efficiency to alleviate cadmium-induced toxicity was determined against a rice cultivar in terms of morphological and biochemical changes. Enhanced growth and reduced oxidative stress were detected in presence of the bacterium. On the basis of these results, it can be concluded that K. michiganensis strain S8 is cadmium accumulating plant growth promoting rhizobacterium that can be applied in cadmium contaminated agricultural soil to achieve better productivity of rice. Copyright © 2018 Elsevier GmbH. All rights reserved.

Production of alpha-hydroxy carboxylic acids and esters from higher sugars using tandem catalyst systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Orazov, Marat; Davis, Mark E.

The present disclosure is directed to methods and composition used in the preparation of alpha-hydroxy carboxylic acids and esters from higher sugars using a tandem catalyst system comprising retro-aldol catalysts and Lewis acid catalysts. In some embodiments, these alpha-hydroxy carboxylic acids may be prepared from pentoses and hexoses. The retro-aldol and Lewis catalysts may be characterized by their respective ability to catalyze a 1,2-carbon shift reaction and a 1,2-hydride shift reaction on an aldose or ketose substrate.

Root ethylene signalling is involved in Miscanthus sinensis growth promotion by the bacterial endophyte Herbaspirillum frisingense GSF30T

PubMed Central

Ludewig, Uwe

2013-01-01

The bacterial endophyte Herbaspirillum frisingense GSF30T is a colonizer of several grasses grown in temperate climates, including the highly nitrogen-efficient perennial energy grass Miscanthus. Inoculation of Miscanthus sinensis seedlings with H. frisingense promoted root and shoot growth but had only a minor impact on nutrient concentrations. The bacterium affected the root architecture and increased fine-root structures. Although H. frisingense has the genetic requirements to fix nitrogen, only minor changes in nitrogen concentrations were observed. Herbaspirillum agglomerates were identified primarily in the root apoplast but also in the shoots. The short-term (3h) and long-term (3 weeks) transcriptomic responses of the plant to bacterial inoculation revealed that H. frisingense induced rapid changes in plant hormone signalling, most prominent in jasmonate signalling. Ethylene signalling pathways were also affected and persisted after 3 weeks in the root. Growth stimulation of the root by the ethylene precursor 1-aminocyclopropane 1-carboxylic acid was dose dependent and was affected by H. frisingense inoculation. Minor changes in the proteome were identified after 3 weeks. This study suggests that H. frisingense improves plant growth by modulating plant hormone signalling pathways and provides a framework to understand the beneficial effects of diazotrophic plant-growth-promoting bacteria, such as H. frisingense, on the biomass grass Miscanthus. PMID:24043849

Structural characterization of 1,3-propanedithiols that feature carboxylic acids: Homologues of mercury chelating agents ✩

PubMed Central

Sattler, Wesley; Palmer, Joshua H.; Bridges, Christy C.; Joshee, Lucy; Zalups, Rudolfs K.; Parkin, Gerard

2013-01-01

The molecular structures of a series of 1,3-propanedithiols that contain carboxylic acid groups, namely rac- and meso-2,4-dimercaptoglutaric acid (H4DMGA) and 2-carboxy-1,3-propanedithiol (H3DMCP), have been determined by X-ray diffraction. Each compound exhibits two centrosymmetric intermolecular hydrogen bonding interactions between pairs of carboxylic acid groups, which result in a dimeric structure for H3DMCP and a polymeric tape-like structure for rac- and meso-H4DMGA. Significantly, the hydrogen bonding motifs observed for rac- and meso-H4DMGA are very different to those observed for the 1,2-dithiol, rac-2,3-dimercaptosuccinic acid (rac-H4DMSA), in which the two oxygen atoms of each carboxylic acid group hydrogen bond to two different carboxylic acid groups, thereby resulting in a hydrogen bonded sheet-like structure rather than a tape. Density functional theory calculations indicate that 1,3-dithiolate coordination to mercury results in larger S–Hg–S bond angles than does 1,2-dithiolate coordination, but these angles are far from linear. As such, κ2-S2 coordination of these dithiolate ligands is expected to be associated with mercury coordination numbers of greater than two. In vivo studies demonstrate that both rac-H4DMGA and H3DMCP reduce the renal burden of mercury in rats, although the compounds are not as effective as either 2,3-dimercaptopropane-1-sulfonic acid (H3DMPS) or meso-H4DMSA. PMID:24187425

Carbodiimide versus click chemistry for nanoparticle surface functionalization: a comparative study for the elaboration of multimodal superparamagnetic nanoparticles targeting αvβ3 integrins.

PubMed

Bolley, Julie; Guenin, Erwann; Lievre, Nicole; Lecouvey, Marc; Soussan, Michael; Lalatonne, Yoann; Motte, Laurence

2013-11-26

Superparamagnetic fluorescent nanoparticles targeting αvβ3 integrins were elaborated using two methodologies: carbodiimide coupling and click chemistries (CuACC and thiol-yne). The nanoparticles are first functionalized with hydroxymethylenebisphonates (HMBP) bearing carboxylic acid or alkyne functions. Then, a large number of these reactives functions were used for the covalent coupling of dyes, poly(ethylene glycol) (PEG), and cyclic RGD. Several methods were used to characterize the nanoparticle surface functionalization, and the magnetic properties of these contrast agents were studied using a 1.5 T clinical MRI. The affinity toward integrins was evidenced by solid-phase receptor-binding assay. In addition to their chemoselective natures, click reactions were shown to be far more efficient than the carbodiimide coupling. The grafting increase was shown to enhance targeting affinity to integrin without imparing MRI and fluorescent properties.

Chemistry of anti-AIDS and anticancer compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, S.

1992-01-01

Several types of prodrugs of 2[prime], 3[prime]-dideoxynucleosides were designed and synthesized for evaluation as anti-AIDS drugs. These prodrugs include 5[prime]-O-acyl-2[prime], 3[prime]-dideoxynucleosides, in which the acyl groups are derived from both aromatic and aliphatic acids, [alpha]-amino acids, diacylglycerol carbonic acids, and diacylglycerol carbamic acids. By applying the pyridium-dihydropyridine redox delivery system to deliver 2[prime], 3[prime]-dideoxynucleosides to the central nervous system, 1,4-dihydropyridine-2[prime], 3[prime]-dideoxy-inosine and -adenosine compounds were synthesized. 5[prime]-Esters of 2[prime], 3[prime]-dideoxyinosine and 2[prime], 3[prime]-dideoxyadenosine were evaluated for their activity against the HIV-1 virus and for delivery to the central nervous system (CNS). The isomerization, hydrolysis, and oxidation of alkyl 1,4-dihydro-N-methylpyridine-3-carboxylates weremore » studied by [sup 1]H and [sup 13]C NMR spectroscopy. Three intermediates, 1,4-dihydro-N-methylpyridine-3-carboxylic acid, alkyl (methyl or isopropyl) 1,6-dihydro-N-methylpyridine-3-carboxylate, and 1,6-dihydro-N-methylpyridine-3-carboxylic acid, were observed by [sup 1]H and [sup 13]C NMR spectroscopy, and their percentages in solution were determined. The structures of the 1,6-dihydropyridine intermediates were confirmed by comparison of the NMR spectra with those of an authentic model compound, methyl N-(4-chlorobenzyl)-1,6-dihydropyridine-3-carboxylate. The rate of hydrolysis of alkyl 1,4-dihydro-N-methylpyridine-3-carboxylates depends on the steric bulk of the O-alkyl group. A new type of 1,4-dihydropyridine drug delivery system with a three-carbon spacer group, 9-[2,3-di-O-acetyl-5-O-[3-(1,4-dihydro-N-methylpyridine-3-carboxamido)propionyl]-[beta]-D-arabinofuranosyl]adenine was designed, synthesized, and evaluated to deliver ara-ADA to the CNS for treatment of herpes encephalitis.« less

Synthesis and biological evaluation of naphthyldesferrithiocin iron chelators.

PubMed

Bergeron, R J; Wiegand, J; Wollenweber, M; McManis, J S; Algee, S E; Ratliff-Thompson, K

1996-04-12

The synthesis and iron-clearing properties of the naphthyldesferrithiocins 2-(2'-hydroxynaphth-1'-yl)-delta2-thiazoline-(4R)-carboxylic acid, 2-(2'-hydroxynaphth-1'-yl)-delta2-thiazoline-(4S)-carboxylic acid, 2-(3'-hydroxynaphth-2'-yl)-delta2-thiazoline-(4R)-carboxylic acid, and 2-(3'-hydroxynaphth-2'-yl)-delta2-thiazoline-(4S)-carboxylic acid are described. While the bile duct-cannulated rat model clearly demonstrates that the 3'-hydroxynaphthyl-2'-yl compounds are orally active iron-clearing agents and the corresponding 2'-hydroxynaphthyl-1'-yl compounds are not, in the primate model none of the benz-fused desazadesferrithiocin analogues are active. Oral versus subcutaneous administration of these ligands strongly suggests that metabolism is a key issue in their iron-clearing properties and that these benz-fused desferrithiocins are not good candidates for orally active iron-clearing drugs.

Sulfur-containing constituents and one 1H-pyrrole-2-carboxylic acid derivative from pineapple [Ananas comosus (L.) Merr.] fruit.

PubMed

Zheng, Zong-Ping; Ma, Jinyu; Cheng, Ka-Wing; Chao, Jianfei; Zhu, Qin; Chang, Raymond Chuen-Chung; Zhao, Ming; Lin, Zhi-Xiu; Wang, Mingfu

2010-12-01

Two sulfur-containing compounds, (S)-2-amino-5-((R)-1-carboxy-2-((E)-3-(4-hydroxy-3-methoxyphenyl)allylthio)ethyl-amino)-5-oxopentanoic acid (1) and (S)-2-amino-5-((R)-1-(carboxymethylamino)-3-((E)-3-(4-hydroxyphenyl)allylthio)-1-oxopropan-2-ylamino)-5-oxopentanoic acid (2), and one 1H-pyrrole-2-carboxylic acid derivative, 6-(3-(1H-pyrrole-2-carbonyloxy)-2-hydroxypropoxy)-3,4,5-trihydroxy-tetrahydro-2H-pyran-2-carboxylic acid (3), together with eighteen known phenolic compounds, were isolated from the fruits of pineapple. Their structures were elucidated by a combination of spectroscopic analyses. Some of these compounds showed inhibitory activities against tyrosinase. The half maximal inhibitory concentration values of compounds 1, 4, 5, 6, 7 are lower than 1 mM. These compounds may contribute to the well-known anti-browning effect of pineapple juice and be potential skin whitening agents in cosmetic applications. Copyright © 2010 Elsevier Ltd. All rights reserved.

Piperidine carboxylic acid derivatives of 10H-pyrazino[2,3-b][1,4]benzothiazine as orally-active adhesion molecule inhibitors.

PubMed

Kaneko, Toshihiko; Clark, Richard S J; Ohi, Norihito; Ozaki, Fumihiro; Kawahara, Tetsuya; Kamada, Atsushi; Okano, Kazuo; Yokohama, Hiromitsu; Ohkuro, Masayoshi; Muramoto, Kenzo; Takenaka, Osamu; Kobayashi, Seiichi

2004-06-01

Novel piperidine carboxylic acid derivatives of 10H-pyrazino[2,3-b][1,4]benzothiazine were prepared and evaluated for their inhibitory activity on the upregulation of adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1). Replacement of the methanesulfonyl group on the piperidine ring of previously prepared derivatives with a carboxylic acid-containing moiety resulted in a number of potent adhesion molecule inhibitors. Of these, (anti) [3-(10H-pyrazino[2,3-b][1,4]benzothiazin-8-yl)methyl-3-azabicyclo[3.3.1]non-9-yl]acetic acid 2q (ER-49890), showed the most potent oral inhibitory activities against neutrophil migration in an interleukin-1 (IL-1) induced paw inflammation model using mice, and leukocyte accumulation in a carrageenan pleurisy model in the rat, and therapeutic effect on collagen-induced arthritis in rats.

Molecular cloning and characterization of two genes for the biotin carboxylase and carboxyltransferase subunits of acetyl coenzyme A carboxylase in Myxococcus xanthus.

PubMed

Kimura, Y; Miyake, R; Tokumasu, Y; Sato, M

2000-10-01

We have cloned a DNA fragment from a genomic library of Myxococcus xanthus using an oligonucleotide probe representing conserved regions of biotin carboxylase subunits of acetyl coenzyme A (acetyl-CoA) carboxylases. The fragment contained two open reading frames (ORF1 and ORF2), designated the accB and accA genes, capable of encoding a 538-amino-acid protein of 58.1 kDa and a 573-amino-acid protein of 61.5 kDa, respectively. The protein (AccA) encoded by the accA gene was strikingly similar to biotin carboxylase subunits of acetyl-CoA and propionyl-CoA carboxylases and of pyruvate carboxylase. The putative motifs for ATP binding, CO(2) fixation, and biotin binding were found in AccA. The accB gene was located upstream of the accA gene, and they formed a two-gene operon. The protein (AccB) encoded by the accB gene showed high degrees of sequence similarity with carboxyltransferase subunits of acetyl-CoA and propionyl-CoA carboxylases and of methylmalonyl-CoA decarboxylase. Carboxybiotin-binding and acyl-CoA-binding domains, which are conserved in several carboxyltransferase subunits of acyl-CoA carboxylases, were found in AccB. An accA disruption mutant showed a reduced growth rate and reduced acetyl-CoA carboxylase activity compared with the wild-type strain. Western blot analysis indicated that the product of the accA gene was a biotinylated protein that was expressed during the exponential growth phase. Based on these results, we propose that this M. xanthus acetyl-CoA carboxylase consists of two subunits, which are encoded by the accB and accA genes, and occupies a position between prokaryotic and eukaryotic acetyl-CoA carboxylases in terms of evolution.

Revised structure for the phenazine antibiotic from Pseudomonas fluorescens 2-79 (NRRL B-15132).

PubMed Central

Brisbane, P G; Janik, L J; Tate, M E; Warren, R F

1987-01-01

A phenazine antibiotic (mp, 243 to 244 degrees C), isolated in a yield of 134 micrograms/ml from cultures of Pseudomonas fluorescens 2-79 (NRRL B-15132), was indistinguishable in all of its measured physicochemical (melting point, UV and infrared spectra, and gas chromatography-mass spectrometry data) and biological properties from synthetic phenazine-1-carboxylic acid. Gurusiddaiah et al. (S. Gurusiddaiah, D. M. Weller, A. Sarkar, and R. J. Cook, Antimicrob. Agents Chemother. 29:488-495, 1986) attributed a dimeric phenazine structure to an antibiotic with demonstrably similar properties obtained from the same bacterial strain. Direct comparison of the physicochemical properties of the authentic antibiotic obtained from D. M. Weller with synthetic phenazine-1-carboxylic acid and with the natural product from the present study established that all three samples were indistinguishable within the experimental error of each method. No evidence to support the existence of a biologically active dimeric species was obtained. Phenazine-1-carboxylic acid has a pKa of 4.24 +/- 0.01 (25 degrees C; I = 0.09), and its carboxylate anion shows no detectable antimicrobial activity compared with the active uncharged carboxylic acid species. These data suggest that phenazine-1-carboxylic acid is probably not an effective biological control agent for phytopathogens in environments with a pH greater than 7. Images PMID:3125789

An enhanced procedure for measuring organic acids and methyl esters in PM2.5

NASA Astrophysics Data System (ADS)

Liu, F.; Duan, F. K.; He, K. B.; Ma, Y. L.; Rahn, K. A.; Zhang, Q.

2015-11-01

A solid-phase extraction (SPE) pretreatment procedure allowing organic acids to be separated from methyl esters in fine aerosol has been developed. The procedure first separates the organic acids from fatty acid methyl esters (FAMEs) and other nonacid organic compounds by aminopropyl-based SPE cartridge and then quantifies them by gas chromatography/mass spectrometry. The procedure prevents the fatty acids and dimethyl phthalate from being overestimated, and so allows us to accurately quantify the C4-C11 dicarboxylic acids (DCAs) and the C8-C30 monocarboxylic acids (MCAs). Results for the extraction of DCAs, MCAs, and AMAs in eluate and FAMEs in effluate by SAX and NH2 SPE cartridges exhibited that the NH2 SPE cartridge gave higher extraction efficiency than the SAX cartridge. The recoveries of analytes ranged from 67.5 to 111.3 %, and the RSD ranged from 0.7 to 10.9 %. The resulting correlations between the aliphatic acids and FAMEs suggest that the FAMEs had sources similar to those of the carboxylic acids, or were formed by esterifying carboxylic acids, or that aliphatic acids were formed by hydrolyzing FAMEs. Through extraction and cleanup using this procedure, 17 aromatic acids in eluate were identified and quantified by gas chromatography/tandem mass spectrometry, including five polycyclic aromatic hydrocarbon (PAH): acids 2-naphthoic, biphenyl-4-carboxylic, 9-oxo-9H-fluorene-1-carboxylic, biphenyl-4,4´-dicarboxylic, and phenanthrene-1-carboxylic acid, plus 1,8-naphthalic anhydride. Correlations between the PAH acids and the dicarboxylic and aromatic acids suggested that the first three acids and 1,8-naphthalic anhydride were secondary atmospheric photochemistry products and the last two mainly primary.

Identification and expression analysis of a putative fatty acidbinding protein gene in the Asian honeybee, Apis cerana cerana.

PubMed

Yu, Xiaoli; Kang, Mingjiang; Liu, Li; Guo, Xingqi; Xu, Baohua

2013-01-01

Fatty acid-binding proteins (FABPs) play pivotal roles in cellular signaling, gene transcription, and lipid metabolism in vertebrates and invertebrates. In this study, a putative FABP gene, referred to as AccFABP, was isolated from the Asian honeybee, Apis cerana cerana Fabricius (Hymenoptera: Apidae). The full-length cDNA consisted of 725 bp, and encoded a protein of 204 amino acids. Homology and phylogenetic analysis indicated that AccFABP was a member of the FABP multifamily. The genomic structure of this gene, which was common among FABP multifamily members, spanned 1,900 bp, and included four exons and three introns. Gene expression analysis revealed that AccFABP was highly expressed in the dark-pigmented phase of pupal development, with peak expression observed in the fat bodies of the dark-pigmented phase pupae. The AccFABP transcripts in the fat body were upregulated by exposure to dietary fatty acids such as conjugated linoleic acid, docosahexaenoic acid, and arachidonic acid. Transcription factor binding sites for Caudal-Related Homeobox and functional CCAAT/enhancer binding site, which were respectively associated with tissue expression and lipid metabolism, were detected in the 5' promoter sequence. The evidence provided in the present study suggests that AccFABP may regulate insect growth and development, and lipid metabolism.

Chemical Preparation Laboratory IND Candidate Compounds.

DTIC Science & Technology

1986-01-21

filtered. The filtrate was neutralized with hydrochloric acid (3.2 L) and the resulting precipitate was collected by filtration. The product was dried...lit. 242-244-) 1.2.4-Triazole-3-carboxylic acid (4)9: 5-Amino-l,2,4-triazole-3- carboxylic acid (1 Kg, 7.8 mol) was dissolved in hot hydrochloric acid ...300 mL), cooled in an ice bath, and adjusted to pH 1 with con- centrated hydrochloric acid (25 mL). The resulting oil started to crystal- lize and the

Synthesis of carbon-11-labeled 4-(phenylamino)-pyrrolo[2,1-f][1,2,4]triazine derivatives as new potential PET tracers for imaging of p38α mitogen-activated protein kinase.

PubMed

Wang, Min; Gao, Mingzhang; Zheng, Qi-Huang

2014-08-15

The reference standards methyl 4-(2-methyl-5-(methoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylate (10a), methyl 4-(2-methyl-5-(ethoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylate (10b) and corresponding precursors 4-(2-methyl-5-(methoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylic acid (11a), methyl 4-(2-methyl-5-(ethoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylic acid (11b) were synthesized from methyl crotonate and 3-amino-4-methylbenzoic acid in multiple steps with moderate to excellent yields. The target tracer [(11)C]methyl 4-(2-methyl-5-(methoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylate ([(11)C]10a) and [(11)C]methyl 4-(2-methyl-5-(ethoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylate ([(11)C]10b) were prepared from their corresponding precursors with [(11)C]CH3OTf under basic condition through O-[(11)C]methylation and isolated by a simplified solid-phase extraction (SPE) method in 50-60% radiochemical yields at end of bombardment (EOB) with 185-555 GBq/μmol specific activity at end of synthesis (EOS). Copyright © 2014 Elsevier Ltd. All rights reserved.

Screening Phosphorylation Site Mutations in Yeast Acetyl-CoA Carboxylase Using Malonyl-CoA Sensor to Improve Malonyl-CoA-Derived Product.

PubMed

Chen, Xiaoxu; Yang, Xiaoyu; Shen, Yu; Hou, Jin; Bao, Xiaoming

2018-01-01

Malonyl-coenzyme A (malonyl-CoA) is a critical precursor for the biosynthesis of a variety of biochemicals. It is synthesized by the catalysis of acetyl-CoA carboxylase (Acc1p), which was demonstrated to be deactivated by the phosphorylation of Snf1 protein kinase in yeast. In this study, we designed a synthetic malonyl-CoA biosensor and used it to screen phosphorylation site mutations of Acc1p in Saccharomyces cerevisiae . Thirteen phosphorylation sites were mutated, and a combination of three site mutations in Acc1p, S686A, S659A, and S1157A, was found to increase malonyl-CoA availability. ACC1 S686AS659AS1157A expression also improved the production of 3-hydroxypropionic acid, a malonyl-CoA-derived chemical, compared to both wild type and the previously reported ACC1 S659AS1157A mutation. This mutation will also be beneficial for other malonyl-CoA-derived products.

Structure-Activity Relationship Study of Ionotropic Glutamate Receptor Antagonist (2S,3R)-3-(3-Carboxyphenyl)pyrrolidine-2-carboxylic Acid.

PubMed

Krogsgaard-Larsen, Niels; Storgaard, Morten; Møller, Charlotte; Demmer, Charles S; Hansen, Jeanette; Han, Liwei; Monrad, Rune N; Nielsen, Birgitte; Tapken, Daniel; Pickering, Darryl S; Kastrup, Jette S; Frydenvang, Karla; Bunch, Lennart

2015-08-13

Herein we describe the first structure-activity relationship study of the broad-range iGluR antagonist (2S,3R)-3-(3-carboxyphenyl)pyrrolidine-2-carboxylic acid (1) by exploring the pharmacological effect of substituents in the 4, 4', or 5' positions and the bioisosteric substitution of the distal carboxylic acid for a phosphonic acid moiety. Of particular interest is a hydroxyl group in the 4' position 2a which induced a preference in binding affinity for homomeric GluK3 over GluK1 (Ki = 0.87 and 4.8 μM, respectively). Two X-ray structures of ligand binding domains were obtained: 2e in GluA2-LBD and 2f in GluK1-LBD, both at 1.9 Å resolution. Compound 2e induces a D1-D2 domain opening in GluA2-LBD of 17.3-18.8° and 2f a domain opening in GluK1-LBD of 17.0-17.5° relative to the structures with glutamate. The pyrrolidine-2-carboxylate moiety of 2e and 2f shows a similar binding mode as kainate. The 3-carboxyphenyl ring of 2e and 2f forms contacts comparable to those of the distal carboxylate in kainate.

21 CFR 74.2705 - FD&C Yellow No. 5.

Code of Federal Regulations, 2010 CFR

2010-04-01

... salt, not more than 0.2 percent. 4,5-Dihydro-5-oxo-1-(4-sulfophenyl)-1H-pyrazole-3-carboxylic acid, disodium salt, not more than 0.2 percent. Ethyl or methyl 4,5-dihydro-5-oxo-1-(4-sulfophenyl)-1H-pyrazole-3...-sulfophenyl)azo]-1H-pyrazole-3-carboxylic acid (CAS Reg. No. 1934-21-0). To manufacture the additive, 4...

Preferential Promotion of Lycopersicon esculentum (Tomato) Growth by Plant Growth Promoting Bacteria Associated with Tomato.

PubMed

Vaikuntapu, Papa Rao; Dutta, Swarnalee; Samudrala, Ram Babu; Rao, Vukanti R V N; Kalam, Sadaf; Podile, Appa Rao

2014-12-01

A total of 74 morphologically distinct bacterial colonies were selected during isolation of bacteria from different parts of tomato plant (rhizoplane, phylloplane and rhizosphere) as well as nearby bulk soil. The isolates were screened for plant growth promoting (PGP) traits such as production of indole acetic acid, siderophore, chitinase and hydrogen cyanide as well as phosphate solubilization. Seven isolates viz., NR4, NR6, RP3, PP1, RS4, RP6 and NR1 that exhibited multiple PGP traits were identified, based on morphological, biochemical and 16S rRNA gene sequence analysis, as species that belonged to four genera Aeromonas, Pseudomonas, Bacillus and Enterobacter. All the seven isolates were positive for 1-aminocyclopropane-1-carboxylate deaminase. Isolate NR6 was antagonistic to Fusarium solani and Fusarium moniliforme, and both PP1 and RP6 isolates were antagonistic to F. moniliforme. Except RP6, all isolates adhered significantly to glass surface suggestive of biofilm formation. Seed bacterization of tomato, groundnut, sorghum and chickpea with the seven bacterial isolates resulted in varied growth response in laboratory assay on half strength Murashige and Skoog medium. Most of the tomato isolates positively influenced tomato growth. The growth response was either neutral or negative with groundnut, sorghum and chickpea. Overall, the results suggested that bacteria with PGP traits do not positively influence the growth of all plants, and certain PGP bacteria may exhibit host-specificity. Among the isolates that positively influenced growth of tomato (NR1, RP3, PP1, RS4 and RP6) only RS4 was isolated from tomato rhizosphere. Therefore, the best PGP bacteria can also be isolated from zones other than rhizosphere or rhizoplane of a plant.

Burkholderia metalliresistens sp. nov., a multiple metal-resistant and phosphate-solubilising species isolated from heavy metal-polluted soil in Southeast China.

PubMed

Guo, Jun Kang; Ding, Yong Zhen; Feng, Ren Wei; Wang, Rui Gang; Xu, Ying Ming; Chen, Chun; Wei, Xiu Li; Chen, Wei Min

2015-06-01

A metal-resistant and phosphate-solubilising bacterium, designated as strain D414(T), was isolated from heavy metal (Pb, Cd, Cu and Zn)-polluted paddy soils at the surrounding area of Dabao Mountain Mine in Southeast China. The minimum inhibitory concentrations of heavy metals for strain D414(T) were 2000 mg L(-1) (Cd), 800 mg L(-1) (Pb), 150 mg L(-1) (Cu) and 2500 mg L(-1) (Zn). The strain possessed plant growth-promoting properties, such as 1-aminocyclopropane-1-carboxylate assimilation, indole production and phosphate solubilisation. Analysis of 16S rRNA gene sequence indicated that the isolate is a member of the genus Burkholderia where strain D414(T) formed a distinct phyletic line with validly described Burkholderia species. Strain D414(T) is closely related to Burkholderia tropica DSM 15359(T), B. bannensis NBRC E25(T) and B. unamae DSM 17197(T), with 98.5, 98.3 and 98.3 % sequence similarities, respectively. Furthermore, less than 34 % DNA-DNA relatedness was detected between strain D414(T) and the type strains of the phylogenetically closest species of Burkholderia. The dominant fatty acids of strain D414(T) were C14:0, C16:0, C17:0 cyclo and C18:1 ω7c. The DNA G+C content was 62.3 ± 0.5 mol%. On the basis of genotypic, phenotypic and phylogenetic data, strain D414(T) represents a novel species, for which the name Burkholderia metalliresistens sp. nov. is proposed, with D414(T) (=CICC 10561(T) = DSM 26823(T)) as the type strain.

Understanding the role of H(2)O(2) during pea seed germination: a combined proteomic and hormone profiling approach.

PubMed

Barba-Espín, Gregorio; Diaz-Vivancos, Pedro; Job, Dominique; Belghazi, Maya; Job, Claudette; Hernández, José Antonio

2011-11-01

In a previous publication, we showed that the treatment of pea seeds in the presence of hydrogen peroxide (H(2)O(2)) increased germination performance as well as seedling growth. To gain insight into the mechanisms responsible for this behaviour, we have analysed the effect of treating mature pea seeds in the presence of 20 mm H(2)O(2) on several oxidative features such as protein carbonylation, endogenous H(2)O(2) and lipid peroxidation levels. We report that H(2)O(2) treatment of the pea seeds increased their endogenous H(2)O(2) content and caused carbonylation of storage proteins and of several metabolic enzymes. Under the same conditions, we also monitored the expression of two MAPK genes known to be activated by H(2)O(2) in adult pea plants. The expression of one of them, PsMAPK2, largely increased upon pea seed imbibition in H(2)O(2) , whereas no change could be observed in expression of the other, PsMAPK3. The levels of several phytohormones such as 1-aminocyclopropane carboxylic acid, indole-3-acetic acid and zeatin appeared to correlate with the measured oxidative indicators and with the expression of PsMAPK2. Globally, our results suggest a key role of H(2)O(2) in the coordination of pea seed germination, acting as a priming factor that involves specific changes at the proteome, transcriptome and hormonal levels. © 2011 Blackwell Publishing Ltd.

Acetyl-CoA carboxylase in Reuber hepatoma cells: variation in enzyme activity, insulin regulation, and cellular lipid content.

PubMed

Bianchi, A; Evans, J L; Nordlund, A C; Watts, T D; Witters, L A

1992-01-01

Reuber hepatoma cells are useful cultured lines for the study of insulin action, lipid and lipoprotein metabolism, and the regulation of acetyl-CoA carboxylase (ACC), the rate-limiting enzyme of fatty acid biosynthesis. During investigations in different clonal lines of these cells, we have uncovered marked intercellular variability in the activity, enzyme content, and insulin regulation of ACC paralleled by differences in cellular neutral lipid (triglyceride) content. Two contrasting clonal lines, Fao and H356A-1, have been studied in detail. Several features distinguish these two lines, including differences in ACC activity and enzyme kinetics, the content of the two major hepatic ACC isozymes (Mr 280,000 and 265,000 Da) and their heteroisozymic complex, the extent of ACC phosphorylation, and the ability of ACC to be activated on stimulation by insulin and insulinomimetic agonists. As studied by Nile Red staining and fluorescence-activated cell sorting, these two lines also display marked differences in neutral lipid content, which correlates with both basal levels of ACC activity and inhibition of ACC by the fatty acid analog, 5-(tetradecyloxy)-2-furoic acid (TOFA). These results emphasize the importance of characterization of any particular clonal line of Reuber cells for studies of enzyme regulation, substrate metabolism, and hormone action. With respect to ACC, studies in contrasting clonal lines of Reuber cells could provide valuable clues to understanding both the complex mechanisms of intracellular ACC regulation in the absence and presence of hormones and its regulatory role(s) in overall hepatic lipid metabolism.

A copper(II) paddle-wheel structure of tranexamic acid: di-chloro-tetra-kis-[μ-4-(ammonio-meth-yl)cyclo-hexane-1-carboxyl-ato-O,O']dicopper(II) dichloride hexa-hydrate.

PubMed

Altaf, Muhammad; Stoeckli-Evans, Helen

2017-10-01

Tranexamic acid [systematic name: trans -4-(amino-meth-yl)cyclo-hexane-1-carb-oxy-lic acid], is an anti-fibrinolytic amino acid that exists as a zwitterion [ trans -4-(ammonio-meth-yl)cyclo-hexane-1-carboxyl-ate] in the solid state. Its reaction with copper chloride leads to the formation of a compound with a copper(II) paddle-wheel structure that crystallizes as a hexa-hydrate, [Cu 2 Cl 2 (C 8 H 15 NO 2 ) 4 ] 2+ ·2Cl - ·6H 2 O. The asymmetric unit is composed of a copper(II) cation, two zwitterionic tranexamic acid units, a coordinating Cl - anion and a free Cl - anion, together with three water mol-ecules of crystallization. The whole structure is generated by inversion symmetry, with the Cu⋯Cu axle of the paddle-wheel dication being located about a center of symmetry. The cyclo-hexane rings of the zwitterionic tranexamic acid units have chair conformations. The carboxyl-ate groups that bridge the two copper(II) cations are inclined to one another by 88.4 (8)°. The copper(II) cation is ligated by four carboxyl-ate O atoms in the equatorial plane and by a Cl - ion in the axial position. Hence, it has a fivefold O 4 Cl coordination sphere with a perfect square-pyramidal geometry and a τ 5 index of zero. In the crystal, the paddle-wheel dications are linked by a series of N-H⋯Cl hydrogen bonds, involving the coordinating and free Cl - ions, forming a three-dimensional network. This network is strengthened by a series of N-H⋯O water , O water -H⋯Cl and O water -H⋯O hydrogen bonds.

Deciphering Staphylococcus sciuri SAT-17 Mediated Anti-oxidative Defense Mechanisms and Growth Modulations in Salt Stressed Maize (Zea mays L.)

PubMed Central

Akram, Muhammad S.; Shahid, Muhammad; Tariq, Mohsin; Azeem, Muhammad; Javed, Muhammad T.; Saleem, Seemab; Riaz, Saba

2016-01-01

Soil salinity severely affects plant nutrient use efficiency and is a worldwide constraint for sustainable crop production. Plant growth-promoting rhizobacteria, with inherent salinity tolerance, are able to enhance plant growth and productivity by inducing modulations in various metabolic pathways. In the present study, we reported the isolation and characterization of a salt-tolerant rhizobacterium from Kallar grass [Leptochloa fusca (L.) Kunth]. Sequencing of the 16S rRNA gene revealed its lineage to Staphylococcus sciuri and it was named as SAT-17. The strain exhibited substantial potential of phosphate solubilization as well as indole-3-acetic acid production (up to 2 M NaCl) and 1-aminocyclopropane-1-carboxylic acid deaminase activity (up to 1.5 M NaCl). Inoculation of a rifampicin-resistant derivative of the SAT-17 with maize, in the absence of salt stress, induced a significant increase in plant biomass together with decreased reactive oxygen species and increased activity of cellular antioxidant enzymes. The derivative strain also significantly accumulated nutrients in roots and shoots, and enhanced chlorophyll and protein contents in comparison with non-inoculated plants. Similar positive effects were observed in the presence of salt stress, although the effect was more prominent at 75 mM in comparison to higher NaCl level (150 mM). The strain survived in the rhizosphere up to 30 days at an optimal population density (ca. 1 × 106 CFU mL-1). It was concluded that S. sciuri strain SAT-17 alleviated maize plants from salt-induced cellular oxidative damage and enhanced growth. Further field experiments should be conducted, considering SAT-17 as a potential bio-fertilizer, to draw parallels between PGPR inoculation, elemental mobility patterns, crop growth and productivity in salt-stressed semi-arid and arid regions. PMID:27375588

Signal enhancement of carboxylic acids by inclusion with β-cyclodextrin in negative high-voltage-assisted laser desorption ionization mass spectrometry.

PubMed

Ren, Xinxin; Liu, Jia; Zhang, Chengsen; Sun, Jiamu; Luo, Hai

2014-01-15

It is difficult to directly analyze carboxylic acids in complex mixtures by ambient high-voltage-assisted laser desorption ionization mass spectrometry (HALDI-MS) in negative ion mode due to the low ionization efficiency of carboxylic acids. A method for the rapid detection of carboxylic acids in negative HALDI-MS has been developed based on their inclusion with β-cyclodextrin (β-CD). The negative HALDI-MS signal-to-noise ratios (S/Ns) of aliphatic, aromatic and hetero atom-containing carboxylic acids can all be significantly improved by forming 1:1 complexes with β-CD. These complexes are mainly formed by specific inclusion interactions which are verified by their collision-induced dissociation behaviors in comparison with that of their corresponding maltoheptaose complexes. A HALDI-MS/MS method has been successfully developed for the detection of α-lipoic acid in complex cosmetics and ibuprofen in a viscous drug suspension. The negative HALDI-MS S/Ns of carboxylic acids can be improved up to 30 times via forming non-covalent complexes with β-CD. The developed method shows the advantages of being rapid and simple, and is promising for rapid detection of active ingredients in complex samples or fast screening of drugs and cosmetics. Copyright © 2013 John Wiley & Sons, Ltd.

Resistance Responses of Potato to Vesicular-Arbuscular Mycorrhizal Fungi under Varying Abiotic Phosphorus Levels.

PubMed

McArthur, D A; Knowles, N R

1992-09-01

In mycorrhizal symbioses, susceptibility of a host plant to infection by fungi is influenced by environmental factors, especially the availability of soil phosphorus. This study describes morphological and biochemical details of interactions between a vesicular-arbuscular mycorrhizal (VAM) fungus and potato (Solanum tuberosum L. cv Russet Burbank) plants, with a particular focus on the physiological basis for P-induced resistance of roots to infection. Root infection by the VAM fungus Glomus fasciculatum ([Thaxt. sensu Gerdemann] Gerdemann and Trappe) was extensive for plants grown with low abiotic P supply, and plant biomass accumulation was enhanced by the symbiosis. The capacity of excised roots from P-deficient plants to produce ethylene in the presence or absence of exogenous 1-amino cyclopropane-1-carboxylic acid (ACC) was markedly reduced by VAM infection. This apparent inhibition of ACC oxidase (ACC(ox)) activity was localized to areas containing infected roots, as demonstrated in split-root studies. Furthermore, leachate from VAM roots contained a potent water-soluble inhibitor of ethylene generation from exogenous ACC by nonmycorrhizal (NM) roots. The leachate from VAM-infected roots had a higher concentration of phenolics, relative to that from NM roots. Moreover, the rates of ethylene formation and phenolic concentration in leachates from VAM roots were inversely correlated, suggesting that this inhibitor may be of a phenolic nature. The specific activity of extracellular peroxidase recovered in root leachates was not stimulated by VAM infection, although activity on a fresh weight basis was significantly enhanced, reflecting the fact that VAM roots had higher protein content than NM roots. Polyphenol oxidase activity of roots did not differ between NM and VAM roots. These results characterize the low resistance response of P-deficient plants to VAM infection. When plants were grown with higher abiotic P supply, the relative benefit of the VAM symbiosis to plant growth decreased and root infection was lower. The in vivo ACC(ox) activity was also greater in roots of plants grown on high levels of P compared with those grown on low levels, although the influence of VAM infection was partially to counteract the nutritional effect of P on ACC(ox) activity. Similar to ACC(ox) activity, extracellular peroxidase activity of roots increased linearly with increasing abiotic P supply, thus indicating a greater potential for resistance to VAM infection. These findings suggest that VAM fungi may alter phenolic metabolism of roots so as to hinder ethylene production and the root's ability to invoke a defense response. Raising the abiotic P supply to plants at least partially restores the capacity of roots to produce ethylene and may, in this way, increase the root's resistance to VAM infection.

Calcite crystal growth rate inhibition by polycarboxylic acids

USGS Publications Warehouse

Reddy, M.M.; Hoch, A.R.

2001-01-01

Calcite crystal growth rates measured in the presence of several polycarboxyclic acids show that tetrahydrofurantetracarboxylic acid (THFTCA) and cyclopentanetetracarboxylic acid (CPTCA) are effective growth rate inhibitors at low solution concentrations (0.01 to 1 mg/L). In contrast, linear polycarbocylic acids (citric acid and tricarballylic acid) had no inhibiting effect on calcite growth rates at concentrations up to 10 mg/L. Calcite crystal growth rate inhibition by cyclic polycarboxyclic acids appears to involve blockage of crystal growth sites on the mineral surface by several carboxylate groups. Growth morphology varied for growth in the absence and in the presence of both THFTCA and CPTCA. More effective growth rate reduction by CPTCA relative to THFTCA suggests that inhibitor carboxylate stereochemical orientation controls calcite surface interaction with carboxylate inhibitors. ?? 20O1 Academic Press.

Chloride channel blockers activate an endogenous cationic current in oocytes of Bufo arenarum.

PubMed

Cavarra, M S; del Mónaco, S M; Kotsias, B A

2004-07-01

A two-electrode, voltage-clamp technique was used to measure the effect of the Cl(-) channel blockers, 9-anthracene carboxylic acid and niflumic acid, upon the ionic currents of oocytes of the South American toad Bufo arenarum. The main results were: (1) both blockers produced a reversible increase of the outward currents on a dose-dependent manner; (2) the activated outward current was voltage dependent; (3) the 9-anthracene carboxylic acid-sensitive current was blocked with barium; and (4) the effect of 9-anthracene carboxylic acid was more pronounced in a zero-K(+) solution than in standard (2 mmol l(-1)) or high (20 mmol l(-1)) K(+) solutions, indicating that a K(+) conductance is activated. The effect of the Cl(-) channel blockers could be due to a direct interaction with endogenous cationic channels. Another possible explanation is that Cl(-) that enter the cell during depolarizing steps in control solution inhibit this cationic conductance; thus, the blockade of Cl(-) channels by 9-anthracene carboxylic acid and niflumic acid would remove this inhibition, allowing the cationic current to flow freely.

Ion-exclusion chromatography with conductimetric detection of aliphatic carboxylic acids on a weakly acidic cation-exchange resin by elution with benzoic acid-beta-cyclodextrin.

PubMed

Tanaka, Kazuhiko; Mori, Masanobu; Xu, Qun; Helaleh, Murad I H; Ikedo, Mikaru; Taoda, Hiroshi; Hu, Wenzhi; Hasebe, Kiyoshi; Fritz, James S; Haddad, Paul R

2003-05-16

In this study, an aqueous solution consisting of benzoic acid with low background conductivity and beta-cyclodextrin (beta-CD) of hydrophilic nature and the inclusion effect to benzoic acid were used as eluent for the ion-exclusion chromatographic separation of aliphatic carboxylic acids with different pKa values and hydrophobicity on a polymethacrylate-based weakly acidic cation-exchange resin in the H+ form. With increasing concentration of beta-cyclodextrin in the eluent, the retention times of the carboxylic acids decreased due to the increased hydrophilicity of the polymethacrylate-based cation-exchange resin surface from the adsorption of OH groups of beta-cyclodextrin. Moreover, the eluent background conductivity decreased with increasing concentration of beta-cyclodextrin in 1 mM benzoic acid, which could result in higher sensitivity for conductimetric detection. The ion-exclusion chromatographic separation of carboxylic acids with high resolution and sensitivity was accomplished successfully by elution with a 1 mM benzoic acid-10 mM cyclodextrin solution without chemical suppression.

Separation of aliphatic carboxylic acids and benzenecarboxylic acids by ion-exclusion chromatography with various cation-exchange resin columns and sulfuric acid as eluent.

PubMed

Ohta, Kazutoku; Ohashi, Masayoshi; Jin, Ji-Ye; Takeuchi, Toyohide; Fujimoto, Chuzo; Choi, Seong-Ho; Ryoo, Jae-Jeong; Lee, Kwang-Pill

2003-05-16

The application of various hydrophilic cation-exchange resins for high-performance liquid chromatography (sulfonated silica gel: TSKgel SP-2SW, carboxylated silica gel: TSKgel CM-2SW, sulfonated polymethacrylate resin: TSKgel SP-5PW, carboxylated polymethacrylate resins: TSKgel CM-5PW and TSKgel OA-Pak A) as stationary phases in ion-exclusion chromatography for C1-C7 aliphatic carboxylic acids (formic, acetic, propionic, butyric, isovaleric, valeric, isocaproic, caproic, 2-methylhexanoic and heptanoic acids) and benzenecarboxylic acids (pyromellitic, trimellitic, hemimellitic, o-phthalic, m-phthalic, p-phthalic, benzoic, salicylic acids and phenol) was carried out using diluted sulfuric acid as the eluent. Silica-based cation-exchange resins (TSKgel SP-2SW and TSKgel CM-2SW) were very suitable for the ion-exclusion chromatographic separation of these benzenecarboxylic acids. Excellent simultaneous separation of these benzenecarboxylic acids was achieved on a TSKgel SP-2SW column (150 x 6 mm I.D.) in 17 min using a 2.5 mM sulfuric acid at pH 2.4 as the eluent. Polymethacrylate-based cation-exchange resins (TSKgel SP-5PW, TSKgel CM-5PW and TSKgel OA-Pak A) acted as advanced stationary phases for the ion-exclusion chromatographic separation of these C1-C7 aliphatic carboxylic acids. Excellent simultaneous separation of these C1-C7 acids was achieved on a TSKgel CM-5PW column (150 x 6 mm I.D.) in 32 min using a 0.05 mM sulfuric acid at pH 4.0 as the eluent.

Apyrase (Nucleoside Triphosphate-Diphosphohydrolase) and Extracellular Nucleotides Regulate Cotton Fiber Elongation in Cultured Ovules1[W][OA

PubMed Central

Clark, Greg; Torres, Jonathan; Finlayson, Scott; Guan, Xueying; Handley, Craig; Lee, Jinsuk; Kays, Julia E.; Chen, Z. Jeffery; Roux, Stanley J.

2010-01-01

Ectoapyrase enzymes remove the terminal phosphate from extracellular nucleoside tri- and diphosphates. In Arabidopsis (Arabidopsis thaliana), two ectoapyrases, AtAPY1 and AtAPY2, have been implicated as key modulators of growth. In fibers of cotton (Gossypium hirsutum), transcript levels for GhAPY1 and GhAPY2, two closely related ectoapyrases that have high sequence similarity to AtAPY1 and AtAPY2, are up-regulated when fibers enter their rapid growth phase. In an ovule culture system, fibers release ATP as they grow, and when their ectoapyrase activity is blocked by the addition of polyclonal anti-apyrase antibodies or by two different small molecule inhibitors, the medium ATP level rises and fiber growth is suppressed. High concentrations of the poorly hydrolyzable nucleotides ATPγS and ADPβS applied to the medium inhibit fiber growth, and low concentrations of them stimulate growth, but treatment with adenosine 5′-O-thiomonophosphate causes no change in the growth rate. Both the inhibition and stimulation of growth by applied nucleotides can be blocked by an antagonist that blocks purinoceptors in animal cells, and by adenosine. Treatment of cotton ovule cultures with ATPγS induces increased levels of ethylene, and two ethylene antagonists, aminovinylglycine and silver nitrate, block both the growth stimulatory and growth inhibitory effects of applied nucleotides. In addition, the ethylene precursor, 1-aminocyclopropane-1-carboxylic acid, lowers the concentration of nucleotide needed to promote fiber growth. These data indicate that ectoapyrases and extracellular nucleotides play a significant role in regulating cotton fiber growth and that ethylene is a likely downstream component of the signaling pathway. PMID:20018604

Nuclear-Cytoplasmic Conflict in Pea (Pisum sativum L.) Is Associated with Nuclear and Plastidic Candidate Genes Encoding Acetyl-CoA Carboxylase Subunits

PubMed Central

Bogdanova, Vera S.; Zaytseva, Olga O.; Mglinets, Anatoliy V.; Shatskaya, Natalia V.; Kosterin, Oleg E.; Vasiliev, Gennadiy V.

2015-01-01

In crosses of wild and cultivated peas (Pisum sativum L.), nuclear-cytoplasmic incompatibility frequently occurs manifested as decreased pollen fertility, male gametophyte lethality, sporophyte lethality. High-throughput sequencing of plastid genomes of one cultivated and four wild pea accessions differing in cross-compatibility was performed. Candidate genes for involvement in the nuclear-plastid conflict were searched in the reconstructed plastid genomes. In the annotated Medicago truncatula genome, nuclear candidate genes were searched in the portion syntenic to the pea chromosome region known to harbor a locus involved in the conflict. In the plastid genomes, a substantial variability of the accD locus represented by nucleotide substitutions and indels was found to correspond to the pattern of cross-compatibility among the accessions analyzed. Amino acid substitutions in the polypeptides encoded by the alleles of a nuclear locus, designated as Bccp3, with a complementary function to accD, fitted the compatibility pattern. The accD locus in the plastid genome encoding beta subunit of the carboxyltransferase of acetyl-coA carboxylase and the nuclear locus Bccp3 encoding biotin carboxyl carrier protein of the same multi-subunit enzyme were nominated as candidate genes for main contribution to nuclear-cytoplasmic incompatibility in peas. Existence of another nuclear locus involved in the accD-mediated conflict is hypothesized. PMID:25789472

Crystal structure and magnetic properties of a unique 3D coordination polymer constructed from flexible aliphatic tricarballylic acid ligands featuring linear trimeric Manganese(II)-based, metal carboxylate chains

NASA Astrophysics Data System (ADS)

Zou, Hua-Hong; Zhang, Shu-Hua; Zeng, Ming-Hua; Zhou, Yan-Ling; Liang, Hong

2008-08-01

A novel linear trimeric-based, Mn(II)-carboxylate chain well separated by long-linking flexible aliphatic tricarballylic acid ligands in a 3D coordination polymer [Mn 3(C 6H 5O 6) 2(H 2O) 4] n ( 1, C 6H 5O 6dbnd CH (COO -)(CH 2COO -) 2, TCA) exhibits low-dimensional antiferromagnetic order at 3.0 K. Such magnetic behavior is arises from the alternate Antiferro-Antiferro-Antiferro' ( J1J1J2) repeating interactions sequence, based on the nature of the binding modes of Mn(II)-carboxylate chain and the effect of interchains arrangement of 1. The reported carboxylate-bridged metal chain systems display a new structurally authenticated example of linear homometallic spin arranged antiferromagnet among metal carboxylates.

Synthesis of some 1,8-dioxoacridine carboxylic acid derivatives and the determination of their ionization constants in ethanol-water mixtures

NASA Astrophysics Data System (ADS)

Saygılı, Rukiye; Ulus, Ramazan; Yeşildağ, İbrahim; Kübra İnal, E.; Kaya, Muharrem; Murat Kalfa, O.; Zeybek, Bülent

2015-03-01

Four novel compounds of 1,8-dioxoacridine carboxylic acid derivatives (4-(3,3,6,6-tetramethyl-1,8-dioxo-9-phenyl-1,2,3,4,5,6,7,8-octahydroacridin-10(9H)-yl)benzoic acid, 4-(9-(4-cyanophenyl)-3,3,6,6-tetramethyl-1,8-dioxo-1,2,3,4,5,6,7,8-octahydroacridin-10(9H)-yl)benzoic acid, 4-(9-(4-hydroxyphenyl)-3,3,6,6-tetramethyl-1,8-dioxo-1,2,3,4,5,6,7,8-octahydroacridin-10(9H)-yl)benzoic acid, 4-(9-(2,4-dichlorophenyl)-3,3,6,6-tetramethyl-1,8-dioxo-1,2,3,4,5,6,7,8-octahydroacridin-10(9H)-yl)benzoic acid) were prepared by the reaction of the 4-substitute benzaldehyde (hydrogen, hydroxyl, cyano, and 2,4-dichloro), 4-aminobenzoic acid, and 5,5-dimethylcyclohexane-1,3-dione in the presence of p-dodecylbenzenesulfonic acid. They were characterized by using FT-IR, 1H-NMR, 13C-NMR, GC-MS spectroscopic techniques. The stoichiometric ionization constants of these compounds were determined in ethanol-water mixtures of 50%, 60% and 70% ethanol (v/v) by potentiometric titration method and the ionization constants were calculated with three different ways. The effects of solvent composition and substituent groups on ionization constants of 1,8-dioxoacridine carboxylic acids were also discussed.

Aromatic carboxylate effect on dimensionality of three bis(benzimidazole)-based cobalt(II) coordination polymers: Syntheses, structures and properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Ju-Wen; Gong, Chun-Hua; Hou, Li-Li

2013-09-15

Three new metal-organic coordination polymers [Co(4-bbc){sub 2}(bbbm)] (1), [Co(3,5-pdc)(bbbm)]·2H{sub 2}O (2) and [Co(1,4-ndc)(bbbm)] (3) (4-Hbbc=4-bromobenzoic acid, 3,5-H{sub 2}pdc=3,5-pyridinedicarboxylic acid, 1,4-H{sub 2}ndc=1,4-naphthalenedicarboxylic acid and bbbm=1,1-(1,4-butanediyl)bis-1H-benzimidazole) were hydrothermally synthesized and structurally characterized. Polymer 1 is a 1D chain formed by the bbbm ligands and Co{sup II} ions. Polymer 2 exhibits a 2D network with a (3·4·5)(3{sup 2}·4·5·6{sup 2}·7{sup 4}) topology. Polymer 3 possesses a 3D three-fold interpenetrating framework. The versatile structures of title polymers indicate that the aromatic carboxylates have an important influence on the dimensionality of 1–3. Moreover, the thermal stability, electrochemical and luminescent properties of 1–3 were investigated. - graphicalmore » abstract: Three bis(benzimidazole)-based cobalt(II) coordination polymers tuned by aromatic carboxylates were hydrothermally synthesized and structurally characterized. The aromatic carboxylates play a key role in the dimensionality of three polymers. The electrochemical and luminescent properties of three polymers were investigated. Display Omitted - Highlights: • Three bis(benzimidazole)-based cobalt(II) coordination polymers tuned by aromatic carboxylates were obtained. • The aromatic carboxylates have an important influence on the dimensionality of three polymers. • The electrochemical and luminescent properties of three polymers were investigated.« less

SCD1 inhibition causes cancer cell death by depleting mono-unsaturated fatty acids.

PubMed

Mason, Paul; Liang, Beirong; Li, Lingyun; Fremgen, Trisha; Murphy, Erin; Quinn, Angela; Madden, Stephen L; Biemann, Hans-Peter; Wang, Bing; Cohen, Aharon; Komarnitsky, Svetlana; Jancsics, Kate; Hirth, Brad; Cooper, Christopher G F; Lee, Edward; Wilson, Sean; Krumbholz, Roy; Schmid, Steven; Xiang, Yibin; Booker, Michael; Lillie, James; Carter, Kara

2012-01-01

Increased metabolism is a requirement for tumor cell proliferation. To understand the dependence of tumor cells on fatty acid metabolism, we evaluated various nodes of the fatty acid synthesis pathway. Using RNAi we have demonstrated that depletion of fatty-acid synthesis pathway enzymes SCD1, FASN, or ACC1 in HCT116 colon cancer cells results in cytotoxicity that is reversible by addition of exogenous fatty acids. This conditional phenotype is most pronounced when SCD1 is depleted. We used this fatty-acid rescue strategy to characterize several small-molecule inhibitors of fatty acid synthesis, including identification of TOFA as a potent SCD1 inhibitor, representing a previously undescribed activity for this compound. Reference FASN and ACC inhibitors show cytotoxicity that is less pronounced than that of TOFA, and fatty-acid rescue profiles consistent with their proposed enzyme targets. Two reference SCD1 inhibitors show low-nanomolar cytotoxicity that is offset by at least two orders of magnitude by exogenous oleate. One of these inhibitors slows growth of HCT116 xenograft tumors. Our data outline an effective strategy for interrogation of on-mechanism potency and pathway-node-specificity of fatty acid synthesis inhibitors, establish an unambiguous link between fatty acid synthesis and cancer cell survival, and point toward SCD1 as a key target in this pathway.

Mechanism of formation of humus coatings on mineral surfaces 1. Evidence for multidentate binding of organic acids from compost leachate on alumina

USGS Publications Warehouse

Wershaw, R. L.; Leenheer, J.A.; Sperline, R.P.; Song, Yuan; Noll, L.A.; Melvin, R.L.; Rigatti, G.P.

1995-01-01

Measurements of the infrared linear dichroism of carboxylate groups of organic acids from compost leachate adsorbed to an alumina surface and the enthalpy of adsorption of this reaction have been made. The linear dichroism measurements indicated that the carboxylate groups are not free to rotate. This limited rotation probably results from bidentate binding of the carboxylate groups. The molar enthalpy of adsorption of the acids is approximately −100 kJ mol−1. This high value for enthalpy of adsorption may best be explained by assuming that two or more carboxylate groups on a single dissolved organic carbon (DOC) molecule coordinate to the surficial aluminium ions.

Hydrocarbon degradation potential and plant growth-promoting activity of culturable endophytic bacteria of Lotus corniculatus and Oenothera biennis from a long-term polluted site.

PubMed

Pawlik, Małgorzata; Cania, Barbara; Thijs, Sofie; Vangronsveld, Jaco; Piotrowska-Seget, Zofia

2017-08-01

Many endophytic bacteria exert beneficial effects on their host, but still little is known about the bacteria associated with plants growing in areas heavily polluted by hydrocarbons. The aim of the study was characterization of culturable hydrocarbon-degrading endophytic bacteria associated with Lotus corniculatus L. and Oenothera biennis L. collected in long-term petroleum hydrocarbon-polluted site using culture-dependent and molecular approaches. A total of 26 hydrocarbon-degrading endophytes from these plants were isolated. Phylogenetic analyses classified the isolates into the phyla Proteobacteria and Actinobacteria. The majority of strains belonged to the genera Rhizobium, Pseudomonas, Stenotrophomonas, and Rhodococcus. More than 90% of the isolates could grow on medium with diesel oil, approximately 20% could use n-hexadecane as a sole carbon and energy source. PCR analysis revealed that 40% of the isolates possessed the P450 gene encoding for cytochrome P450-type alkane hydroxylase (CYP153). In in vitro tests, all endophytic strains demonstrated a wide range of plant growth-promoting traits such as production of indole-3-acetic acid, hydrogen cyanide, siderophores, and phosphate solubilization. More than 40% of the bacteria carried the gene encoding for the 1-aminocyclopropane-1-carboxylic acid deaminase (acdS). Our study shows that the diversity of endophytic bacterial communities in tested plants was different. The results revealed also that the investigated plants were colonized by endophytic bacteria possessing plant growth-promoting features and a clear potential to degrade hydrocarbons. The properties of isolated endophytes indicate that they have the high potential to improve phytoremediation of petroleum hydrocarbon-polluted soils.

Bioaugmentation with cadmium-resistant plant growth-promoting rhizobacteria to assist cadmium phytoextraction by Helianthus annuus.

PubMed

Prapagdee, Benjaphorn; Chanprasert, Maesinee; Mongkolsuk, Skorn

2013-07-01

Micrococcus sp. MU1 and Klebsiella sp. BAM1, the cadmium-resistant plant growth-promoting rhizobacteria (PGPR), produce high levels of indole-3-acetic acid (IAA) during the late stationary phase of their growth. The ability of PGPR to promote root elongation, plant growth and cadmium uptake in sunflowers (Helianthus annuus) was evaluated. Both species of bacteria were able to remove cadmium ions from an aqueous solution and enhanced cadmium mobilization in contaminated soil. Micrococcus sp. and Klebsiella sp. use aminocyclopropane carboxylic acid as a nitrogen source to support their growth, and the minimum inhibitory concentrations of cadmium for Micrococcus sp. and Klebsiella sp. were 1000 and 800mM, respectively. These bacteria promoted root elongation in H. annuus seedlings in both the absence and presence of cadmium compared to uninoculated seedlings. Inoculation with these bacteria was found to increase the root lengths of H. annuus that had been planted in cadmium-contaminated soil. An increase in dry weight was observed for H. annuus inoculated with Micrococcus sp. Moreover, Micrococcus sp. enhanced the accumulation of cadmium in the root and leaf of H. annuus compared to untreated plants. The highest cadmium accumulation in the whole plant was observed when the plants were treated with EDTA following the treatment with Micrococcus sp. In addition, the highest translocation of cadmium from root to the above-ground tissues of H. annuus was found after treatment with Klebsiella sp. in the fourth week after planting. Our results show that plant growth and cadmium accumulation in H. annuus was significantly enhanced by cadmium-resistant PGPRs, and these bacterial inoculants are excellent promoters of phytoextraction for the rehabilitation of heavy metal-polluted environments. Copyright © 2013 Elsevier Ltd. All rights reserved.

A Chemogenomic Screen Reveals Novel Snf1p/AMPK Independent Regulators of Acetyl-CoA Carboxylase.

PubMed

Bozaquel-Morais, Bruno L; Madeira, Juliana B; Venâncio, Thiago M; Pacheco-Rosa, Thiago; Masuda, Claudio A; Montero-Lomeli, Monica

2017-01-01

Acetyl-CoA carboxylase (Acc1p) is a key enzyme in fatty acid biosynthesis and is essential for cell viability. To discover new regulators of its activity, we screened a Saccharomyces cerevisiae deletion library for increased sensitivity to soraphen A, a potent Acc1p inhibitor. The hits identified in the screen (118 hits) were filtered using a chemical-phenotype map to exclude those associated with pleiotropic drug resistance. This enabled the identification of 82 ORFs that are genetic interactors of Acc1p. The main functional clusters represented by these hits were "transcriptional regulation", "protein post-translational modifications" and "lipid metabolism". Further investigation of the "transcriptional regulation" cluster revealed that soraphen A sensitivity is poorly correlated with ACC1 transcript levels. We also studied the three top unknown ORFs that affected soraphen A sensitivity: SOR1 (YDL129W), SOR2 (YIL092W) and SOR3 (YJR039W). Since the C18/C16 ratio of lipid acyl lengths reflects Acc1p activity levels, we evaluated this ratio in the three mutants. Deletion of SOR2 and SOR3 led to reduced acyl lengths, suggesting that Acc1p is indeed down-regulated in these strains. Also, these mutants showed no differences in Snf1p/AMPK activation status and deletion of SNF1 in these backgrounds did not revert soraphen A sensitivity completely. Furthermore, plasmid maintenance was reduced in sor2Δ strain and this trait was shared with 18 other soraphen A sensitive hits. In summary, our screen uncovered novel Acc1p Snf1p/AMPK-independent regulators.

Atmospheric chemistry of carboxylic acids: microbial implication versus photochemistry

NASA Astrophysics Data System (ADS)

Vaïtilingom, M.; Charbouillot, T.; Deguillaume, L.; Maisonobe, R.; Parazols, M.; Amato, P.; Sancelme, M.; Delort, A.-M.

2011-02-01

Clouds are multiphasic atmospheric systems in which the dissolved organic compounds, dominated by carboxylic acids, are subject to multiple chemical transformations in the aqueous phase. Among them, solar radiation, by generating hydroxyl radicals (•OH), is considered as the main catalyzer of the reactivity of organic species in clouds. We investigated to which extent the active biomass existing in cloud water represents an alternative route to the chemical reactivity of carboxylic acids. Pure cultures of seventeen bacterial strains (Arthrobacter, Bacillus, Clavibacter, Frigoribacterium, Pseudomonas, Sphingomonas and Rhodococcus), previously isolated from cloud water and representative of the viable community of clouds were first individually incubated in two artificial bulk cloud water solutions at 17 °C and 5 °C. These solutions mimicked the chemical composition of cloud water from "marine" and "continental" air masses, and contained the major carboxylic acids existing in the cloud water (i.e. acetate, formate, succinate and oxalate). The concentrations of these carboxylic compounds were monitored over time and biodegradation rates were determined. In average, they ranged from 2 ×10-19 for succinate to 1 × 10-18 mol cell-1 s-1 for formate at 17 °C and from 4 × 10-20 for succinate to 6 × 10-19 mol cell-1 s-1 for formate at 5 °C, with no significant difference between "marine" and "continental" media. In parallel, irradiation experiments were also conducted in these two artificial media to compare biodegradation and photodegradation of carboxylic compounds. To complete this comparison, the photodegradation rates of carboxylic acids by •OH radicals were calculated from literature data. Inferred estimations suggested a significant participation of microbes to the transformation of carboxylic acids in cloud water, particularly for acetate and succinate (up to 90%). Furthermore, a natural cloud water sample was incubated (including its indigenous microflora); the rates of biodegradation were determined and compared to the photodegradation rates involving •OH radicals. The biodegradation rates in "natural" and "artificial" cloud water were in the same order of magnitude; this confirms the significant role of the active biomass in the aqueous reactivity of clouds.

Hydrogen bonded binary molecular adducts derived from exobidentate N-donor ligand with dicarboxylic acids: Acid⋯imidazole hydrogen-bonding interactions in neutral and ionic heterosynthons

NASA Astrophysics Data System (ADS)

Kathalikkattil, Amal Cherian; Damodaran, Subin; Bisht, Kamal Kumar; Suresh, Eringathodi

2011-01-01

Four new binary molecular compounds between a flexible exobidentate N-heterocycle and a series of dicarboxylic acids have been synthesized. The N-donor 1,4-bis(imidazol-1-ylmethyl)benzene (bix) was reacted with flexible and rigid dicarboxylic acids viz., cyclohexane-1,4-dicarboxylic acid (H 2chdc), naphthalene-1,4-dicarboxylic acid (H 2npdc) and 1H-pyrazole-3,5-dicarboxylic acid (H 2pzdc), generating four binary molecular complexes. X-ray crystallographic investigation of the molecular adducts revealed the primary intermolecular interactions carboxylic acid⋯amine (via O-H⋯N) as well as carboxylate⋯protonated amine (via N-H +⋯O -) within the binary compounds, generating layered and two-dimensional sheet type H-bonded networks involving secondary weak interactions (C-H⋯O) including the solvent of crystallization. Depending on the differences in p Ka values of the selected base/acid (Δp Ka), diverse H-bonded supramolecular assemblies could be premeditated. This study demonstrates the H-bonding interactions between imidazole/imidazolium cation and carboxylic acid/carboxylate anion in providing sufficient driving force for the directed assembly of binary molecular complexes. In the two-component solid form of hetero synthons involving bix and dicarboxylic acid, only H 2chdc exist as cocrystal with bix, while all the other three compounds crystallized exclusively as salt, in agreement with the Δp Ka values predicted for the formation of salts/cocrystals from the base and acid used in the synthesis of supramolecular solids.

Design of co-crystals/salts of some Nitrogenous bases and some derivatives of thiophene carboxylic acids through a combination of hydrogen and halogen bonds.

PubMed

Jennifer, Samson Jegan; Muthiah, Packianathan Thomas

2014-01-01

The utility of N-heterocyclic bases to obtain molecular complexes with carboxylic acids is well studied. Depending on the solid state interaction between the N-heterocyclic base and a carboxylic acid a variety of neutral or ionic synthons are observed. Meanwhile, pyridines and pyrimidines have been frequently chosen in the area of crystal engineering for their multipurpose functionality. HT (hetero trimers) and LHT (linear heterotetramers) are the well known synthons that are formed in the presence of pyrimidines and carboxylic acids. Fourteen crystals involving various substituted thiophene carboxylic acid derivatives and nitrogenous bases were prepared and characterized by using single crystal X-ray diffraction. The 14 crystals can further be divided into two groups [1a-7a], [8b-14b] based on the nature of the nitrogenous base. Carboxylic acid to pyridine proton transfer has occurred in 3 compounds of each group. In addition to the commonly occurring hydrogen bond based pyridine/carboxylic acid and pyrimidine/carboxylic acid synthons which is the reason for assembly of primary motifs, various other interactions like Cl…Cl, Cl…O, C-H…Cl, C-H…S add additional support in organizing these supermolecules into extended architectures. It is also interesting to note that in all the compounds π-π stacking occurs between the pyrimidine-pyrimidine or pyridine-pyridine or acid-acid moieties rather than acid-pyrimidine/pyridine. In all the compounds (1a-14b) either neutral O-H…Npyridyl/pyrimidine or charge-assisted Npyridinium-H…Ocarboxylate hydrogen bonds are present. The HT (hetero trimers) and LHT (linear heterotetramers) are dominant in the crystal structures of the adducts containing N-heterocyclic bases with two proton acceptors (1a-7a). Similar type supramolecular ladders are observed in 5TPC44BIPY (8b), TPC44BIPY (9b), TPC44TMBP (11b). Among the seven compounds [8b-14b] the extended ligands are linear in all except for the TMBP (10b, 11b, 12b). The structure of each compound depends on the dihedral angle between the carboxyl group and the nitrogenous base. All these compounds indicate three main synthons that regularly occur, namely linear heterodimer (HD), heterotrimer (HT) and heterotetramer (LHT).

Phenazine-1-carboxylic acid influences biofilm development and turnover of rhizobacterial biomass in a soil moisture-dependent manner

USDA-ARS?s Scientific Manuscript database

Rhizobacterial biofilm development influences terrestrial carbon and nitrogen cycles with ramifications for crop and soil health. Phenazine-1-carboxylic acid (PCA) is a redox-active metabolite produced by rhizobacteria in dryland wheat fields of Washington and Oregon, USA. PCA promotes biofilm dev...

Fatty acid synthase inhibition in human breast cancer cells leads to malonyl-CoA-induced inhibition of fatty acid oxidation and cytotoxicity.

PubMed

Thupari, J N; Pinn, M L; Kuhajda, F P

2001-07-13

Inhibition of fatty acid synthase (FAS) induces apoptosis in human breast cancer cells in vitro and in vivo without toxicity to proliferating normal cells. We have previously shown that FAS inhibition causes a rapid increase in malonyl-CoA levels identifying malonyl-CoA as a potential trigger of apoptosis. In this study we further investigated the role of malonyl-CoA during FAS inhibition. We have found that: [i] inhibition of FAS with cerulenin causes carnitine palmitoyltransferase-1 (CPT-1) inhibition and fatty acid oxidation inhibition in MCF-7 human breast cancer cells likely mediated by elevation of malonyl-CoA; [ii] cerulenin cytotoxicity is due to the nonphysiological state of increased malonyl-CoA, decreased fatty acid oxidation, and decreased fatty acid synthesis; and [iii] the cytotoxic effect of cerulenin can be mimicked by simultaneous inhibition of CPT-1, with etomoxir, and fatty acid synthesis with TOFA, an acetyl-CoA carboxylase (ACC) inhibitor. This study identifies CPT-1 and ACC as two new potential targets for cancer chemotherapy. Copyright 2001 Academic Press.

Strong-acid, carboxyl-group structures in fulvic acid from the Suwannee River, Georgia. 1. Minor structures

USGS Publications Warehouse

Leenheer, J.A.; Wershaw, R. L.; Reddy, M.M.

1995-01-01

An investigation of the strong-acid characteristics (pKa 3.0 or less) of fulvic acid from the Suwannee River, Georgia, was conducted. Quantitative determinations were made for amino acid and sulfur-containing acid structures, oxalate half-ester structures, malonic acid structures, keto acid structures, and aromatic carboxyl-group structures. These determinations were made by using a variety of spectrometric (13C-nuclear magnetic resonance, infrared, and ultraviolet spectrometry) and titrimetric characterizations on fulvic acid or fulvic acid samples that were chemically derivatized to indicate certain functional groups. Only keto acid and aromatic carboxyl-group structures contributed significantly to the strong-acid characteristics of the fulvic acid; these structures accounted for 43% of the strong-acid acidity. The remaining 57% of the strong acids are aliphatic carboxyl groups in unusual and/or complex configurations for which limited model compound data are available.

(CF3CO)2O/CF3SO3H-mediated synthesis of 1,3-diketones from carboxylic acids and aromatic ketones

PubMed Central

Kim, JungKeun; Shokova, Elvira; Tafeenko, Victor

2014-01-01

Summary A very simple and convenient reaction for 1,3-diketone preparation from carboxylic acids and aromatic ketones in TFAA/TfOH system is described. When the β-phenylpropionic acids were used as starting materials, they initially gave 1-indanones and then underwent further acylation with the formation of 2-(β-phenylpropionyl)-1-indanones as the main reaction products. In addition, the application of the proposed protocol allowed for the synthesis of selected polysubstituted pyrazoles in a one-pot procedure directly from acids and ketones. PMID:25298794

Enhanced degradation of chlorpyrifos in rice (Oryza sativa L.) by five strains of endophytic bacteria and their plant growth promotional ability.

PubMed

Feng, Fayun; Ge, Jing; Li, Yisong; He, Shuang; Zhong, Jianfeng; Liu, Xianjing; Yu, Xiangyang

2017-10-01

Endophytic bacteria reside in plant tissues, such as roots, stems, leaves and seeds. Most of them can stimulate plant growth or alleviate phytotoxicity of pollutants. There are handful species with dual functions stimulating plant growth and degrading pollutants have been reported. Five endophytic bacteria were isolated from chlorpyrifos (CP) treated rice plants and identified as Pseudomonas aeruginosa strain RRA, Bacillus megaterium strain RRB, Sphingobacterium siyangensis strain RSA, Stenotrophomonas pavanii strain RSB and Curtobacterium plantarum strain RSC according to morphological characteristics, physiological and biochemical tests, and 16S rDNA phylogeny. All of them possessed some plant growth promotional traits, including indole acetic acid and siderophore production, secretion of phosphate solubilization and 1-aminocyclopropane-1-carboxylate deaminase. The bacteria were marked with the green fluorescent protein (gfp) gene and successfully colonized into rice plants. All isolates were able to degrade CP in vitro and in vivo. The five isolates degraded more than 90% of CP in 24 h when the initial concentration was lower than 5 mg/L. CP degradation was significantly enhanced in the infested rice plants and rice grains. The final CP residual was reduced up to 80% in the infested rice grains compared to the controls. The results indicate that these isolates are promising bio-inoculants for the removal or detoxification of CP residues in rice plants and grains. Copyright © 2017 Elsevier Ltd. All rights reserved.

Isolation of Endophytic Plant Growth-Promoting Bacteria Associated with the Halophyte Salicornia europaea and Evaluation of their Promoting Activity Under Salt Stress.

PubMed

Zhao, Shuai; Zhou, Na; Zhao, Zheng-Yong; Zhang, Ke; Wu, Guo-Hua; Tian, Chang-Yan

2016-10-01

Several reports have highlighted that many plant growth-promoting endophytic bacteria (PGPE) can assist their host plants in coping with various biotic and abiotic stresses. However, information about the PGPE colonizing in the halophytes is still scarce. This study was designed to isolate and characterize PGPE from salt-accumulating halophyte Salicornia europaea grown under extreme salinity and to evaluate in vitro the bacterial mechanisms related to plant growth promotion. A total of 105 isolates were obtained from the surface-sterilized roots, stems, and assimilation twigs of S. europaea. Thirty-two isolates were initially selected for their ability to produce 1-aminocyclopropane-1-carboxylate deaminase as well as other properties such as production of indole-3-acetic acid and phosphate-solubilizing activities. The 16S rRNA gene-sequencing analysis revealed that these isolates belong to 13 different genera and 19 bacterial species. For these 32 strains, seed germination and seedling growth in axenically grown S. europaea seedlings at different NaCl concentrations (50-500 mM) were quantified. Five isolates possessing significant stimulation of the host plant growth were obtained. The five isolates were identified as Bacillus endophyticus, Bacillus tequilensis, Planococcus rifietoensis, Variovorax paradoxus, and Arthrobacter agilis. All the five strains could colonize and can be reisolated from the host plant interior tissues. These results demonstrate that habitat-adapted PGPE isolated from halophyte could enhance plant growth under saline stress conditions.

Identification of Pseudomonas aeruginosa Phenazines that Kill Caenorhabditis elegans

PubMed Central

Cezairliyan, Brent; Vinayavekhin, Nawaporn; Grenfell-Lee, Daniel; Yuen, Grace J.; Saghatelian, Alan; Ausubel, Frederick M.

2013-01-01

Pathogenic microbes employ a variety of methods to overcome host defenses, including the production and dispersal of molecules that are toxic to their hosts. Pseudomonas aeruginosa, a Gram-negative bacterium, is a pathogen of a diverse variety of hosts including mammals and the nematode Caenorhabditis elegans. In this study, we identify three small molecules in the phenazine class that are produced by P. aeruginosa strain PA14 that are toxic to C. elegans. We demonstrate that 1-hydroxyphenazine, phenazine-1-carboxylic acid, and pyocyanin are capable of killing nematodes in a matter of hours. 1-hydroxyphenazine is toxic over a wide pH range, whereas the toxicities of phenazine-1-carboxylic acid and pyocyanin are pH-dependent at non-overlapping pH ranges. We found that acidification of the growth medium by PA14 activates the toxicity of phenazine-1-carboxylic acid, which is the primary toxic agent towards C. elegans in our assay. Pyocyanin is not toxic under acidic conditions and 1-hydroxyphenazine is produced at concentrations too low to kill C. elegans. These results suggest a role for phenazine-1-carboxylic acid in mammalian pathogenesis because PA14 mutants deficient in phenazine production have been shown to be defective in pathogenesis in mice. More generally, these data demonstrate how diversity within a class of metabolites could affect bacterial toxicity in different environmental niches. PMID:23300454

Heterologous co-expression of accA, fabD, and thioesterase genes for improving long-chain fatty acid production in Pseudomonas aeruginosa and Escherichia coli.

PubMed

Lee, Sunhee; Jeon, Eunyoung; Jung, Yeontae; Lee, Jinwon

2012-05-01

The goal of the present study was to increase the content of intracellular long-chain fatty acids in two bacterial strains, Pseudomonas aeruginosa PA14 and Escherichia coli K-12 MG1655, by co-overexpressing essential enzymes that are involved in the fatty acid synthesis metabolic pathway. Recently, microbial fatty acids and their derivatives have been receiving increasing attention as an alternative source of fuel. By introducing two genes (accA and fabD) of P. aeruginosa into the two bacterial strains and by co-expressing with them the fatty acyl-acyl carrier protein thioesterase gene of Streptococcus pyogenes (strain MGAS10270), we have engineered recombinant strains that are efficient producers of long-chain fatty acids (C16 and C18). The recombinant strains exhibit a 1.3-1.7-fold increase in the production of long-chain fatty acids over the wild-type strains. To enhance the production of total long-chain fatty acids, we researched the carbon sources for optimized culture conditions and results were used for post-culture incubation period. E. coli SGJS17 (containing the accA, fabD, and thioesterase genes) produced the highest content of intracellular total fatty acids; in particular, the unsaturated fatty acid content was about 20-fold higher than that in the wild-type E. coli.

Screening and Evaluation of the Bioremediation Potential of Cu/Zn-Resistant, Autochthonous Acinetobacter sp. FQ-44 from Sonchus oleraceus L.

PubMed

Fang, Qing; Fan, Zhengqiu; Xie, Yujing; Wang, Xiangrong; Li, Kun; Liu, Yafeng

2016-01-01

The quest for new, promising and indigenous plant growth-promoting rhizobacteria and a deeper understanding of their relationship with plants are important considerations in the improvement of phytoremediation. This study focuses on the screening of plant beneficial Cu/Zn-resistant strains and assessment of their bioremediation potential (metal solubilization/tolerance/biosorption and effects on growth of Brassica napus seedlings) to identify suitable rhizobacteria and examine their roles in microbes-assisted phytoremediation. Sixty Cu/Zn-resistant rhizobacteria were initially isolated from Sonchus oleraceus grown at a multi-metal-polluted site in Shanghai, China. From these strains, 19 isolates that were all resistant to 300 mg⋅L -1 Cu as well as 300 mg⋅L -1 Zn, and could simultaneously grow on Dworkin-Foster salt minimal medium containing 1-aminocyclopropane-1-carboxylic acid were preliminarily selected. Of those 19 isolates, 10 isolates with superior plant growth-promoting properties (indole-3-acetic acid production, siderophore production, and insoluble phosphate solubilization) were secondly chosen and further evaluated to identify those with the highest bioremediation potential and capacity for bioaugmentation. Strain S44, identified as Acinetobacter sp. FQ-44 based on 16S rDNA sequencing, was specifically chosen as the most favorable strain owing to its strong capabilities to (1) promote the growth of rape seedlings (significantly increased root length, shoot length, and fresh weight by 92.60%, 31.00%, and 41.96%, respectively) under gnotobiotic conditions; (2) tolerate up to 1000 mg⋅L -1 Cu and 800 mg⋅L -1 Zn; (3) mobilize the highest concentrations of water-soluble Cu, Zn, Pb, and Fe (16.99, 0.98, 0.08, and 3.03 mg⋅L -1 , respectively); and (4) adsorb the greatest quantities of Cu and Zn (7.53 and 6.61 mg⋅g -1 dry cell, respectively). Our findings suggest that Acinetobacter sp. FQ-44 could be exploited for bacteria-assisted phytoextraction. Moreover, the present study provides a comprehensive method for the screening of rhizobacteria for phytoremediation of multi-metal-polluted soils, especially those sewage sludge-amended soils contaminated with Cu/Zn.

Screening and Evaluation of the Bioremediation Potential of Cu/Zn-Resistant, Autochthonous Acinetobacter sp. FQ-44 from Sonchus oleraceus L.

PubMed Central

Fang, Qing; Fan, Zhengqiu; Xie, Yujing; Wang, Xiangrong; Li, Kun; Liu, Yafeng

2016-01-01

The quest for new, promising and indigenous plant growth-promoting rhizobacteria and a deeper understanding of their relationship with plants are important considerations in the improvement of phytoremediation. This study focuses on the screening of plant beneficial Cu/Zn-resistant strains and assessment of their bioremediation potential (metal solubilization/tolerance/biosorption and effects on growth of Brassica napus seedlings) to identify suitable rhizobacteria and examine their roles in microbes-assisted phytoremediation. Sixty Cu/Zn-resistant rhizobacteria were initially isolated from Sonchus oleraceus grown at a multi-metal-polluted site in Shanghai, China. From these strains, 19 isolates that were all resistant to 300 mg⋅L-1 Cu as well as 300 mg⋅L-1 Zn, and could simultaneously grow on Dworkin–Foster salt minimal medium containing 1-aminocyclopropane-1-carboxylic acid were preliminarily selected. Of those 19 isolates, 10 isolates with superior plant growth-promoting properties (indole-3-acetic acid production, siderophore production, and insoluble phosphate solubilization) were secondly chosen and further evaluated to identify those with the highest bioremediation potential and capacity for bioaugmentation. Strain S44, identified as Acinetobacter sp. FQ-44 based on 16S rDNA sequencing, was specifically chosen as the most favorable strain owing to its strong capabilities to (1) promote the growth of rape seedlings (significantly increased root length, shoot length, and fresh weight by 92.60%, 31.00%, and 41.96%, respectively) under gnotobiotic conditions; (2) tolerate up to 1000 mg⋅L-1 Cu and 800 mg⋅L-1 Zn; (3) mobilize the highest concentrations of water-soluble Cu, Zn, Pb, and Fe (16.99, 0.98, 0.08, and 3.03 mg⋅L-1, respectively); and (4) adsorb the greatest quantities of Cu and Zn (7.53 and 6.61 mg⋅g-1 dry cell, respectively). Our findings suggest that Acinetobacter sp. FQ-44 could be exploited for bacteria-assisted phytoextraction. Moreover, the present study provides a comprehensive method for the screening of rhizobacteria for phytoremediation of multi-metal-polluted soils, especially those sewage sludge-amended soils contaminated with Cu/Zn. PMID:27746807

Structural environments of carboxyl groups in natural organic molecules from terrestrial systems. Part 2: 2D NMR spectroscopy

NASA Astrophysics Data System (ADS)

Deshmukh, Ashish P.; Pacheco, Carlos; Hay, Michael B.; Myneni, Satish C. B.

2007-07-01

Carboxyl groups are abundant in natural organic molecules (NOM) and play a major role in their reactivity. The structural environments of carboxyl groups in IHSS soil and river humic samples were investigated using 2D NMR (heteronuclear and homonuclear correlation) spectroscopy. Based on the 1H- 13C heteronuclear multiple-bond correlation (HMBC) spectroscopy results, the carboxyl environments in NOM were categorized as Type I (unsubstituted and alkyl-substituted aliphatic/alicyclic), Type II (functionalized carbon substituted), Type IIIa, b (heteroatom and olefin substituted), and Type IVa, b (5-membered heterocyclic aromatic and 6-membered aromatic). The most intense signal in the HMBC spectra comes from the Type I carboxyl groups, including the 2JCH and 3JCH couplings of unsubstituted aliphatic and alicyclic acids, though this spectral region also includes the 3JCH couplings of Type II and III structures. Type II and III carboxyls have small but detectable 2JCH correlations in all NOM samples except for the Suwannee River humic acid. Signals from carboxyls bonded to 5-membered aromatic heterocyclic fragments (Type IVa) are observed in the soil HA and Suwannee River FA, while correlations to 6-membered aromatics (Type IVb) are only observed in Suwannee River HA. In general, aromatic carboxylic acids may be present at concentrations lower than previously imagined in these samples. Vibrational spectroscopy results for these NOM samples, described in an accompanying paper [Hay M. B. and Myneni S. C. B. (2007) Structural environments of carboxyl groups in natural organic molecules from terrestrial systems. Part 1: Infrared spectroscopy. Geochim. Cosmochim. Acta (in press)], suggest that Type II and Type III carboxylic acids with α substituents (e.g., -OH, -OR, or -CO 2H) constitute the majority of carboxyl structures in all humic substances examined. Furoic and salicylic acid structures (Type IV) are also feasible fragments, albeit as minor constituents. The vibrational spectroscopy results also suggest that much of the "Type I" signal observed in the HMBC spectrum is due to carboxylic acid esters and possibly α-substituted alicyclic acids.

Separation of certain carboxylic acids utilizing cation exchange membranes

DOEpatents

Chum, H.L.; Sopher, D.W.

1983-05-09

A method of substantially separating monofunctional lower carboxylic acids from a liquid mixture containing the acids wherein the pH of the mixture is adjusted to a value in the range of from about 1 to about 5 to form protonated acids. The mixture is heated to an elevated temperature not greater than about 100/sup 0/C and brought in contact with one side of a perfluorinated cation exchange membrane having sulfonate or carboxylate groups or mixtures thereof with the mixture containing the protonated acids. A pressure gradient can be established across the membrane with the mixture being under higher pressure, so that protonated monofunctional lower carboxylic acids pass through the membrane at a substantially faster rate than the remainder of the mixture thereby substantially separating the acids from the mixture.

Separation of certain carboxylic acids utilizing cation exchange membranes

DOEpatents

Chum, Helena L.; Sopher, David W.

1984-01-01

A method of substantially separating monofunctional lower carboxylic acids from a liquid mixture containing the acids wherein the pH of the mixture is adjusted to a value in the range of from about 1 to about 5 to form protonated acids. The mixture is heated to an elevated temperature not greater than about 100.degree. C. and brought in contact with one side of a perfluorinated cation exchange membrane having sulfonate or carboxylate groups or mixtures thereof with the mixture containing the protonated acids. A pressure gradient can be established across the membrane with the mixture being under higher pressure, so that protonated monofunctional lower carboxylic acids pass through the membrane at a substantially faster rate than the remainder of the mixture thereby substantially separating the acids from the mixture.

Simultaneous determination of C1-C4 carboxylic acids and aldehydes using 2,4-dinitrophenylhydrazine-impregnated silica gel and high-performance liquid chromatography.

PubMed

Uchiyama, Shigehisa; Matsushima, Erika; Aoyagi, Shohei; Ando, Masanori

2004-10-01

A new method for the simultaneous determination of aliphatic carboxylic acids and aldehydes in air is described. In this work, carboxylic acids were allowed to react with 2,4-dinitrophenylhydrazine (DNPH) to form the corresponding carboxylic 2,4-dinitrophenylhydrazides. These derivatives have excellent thermal stability, with melting points higher than those of the corresponding hydrazones by 32-50 degrees C. C1-C4 carboxylic acid 2,4-dinitrophenylhydrazides exhibited maximum absorption wavelengths of 331-334 nm and molar absorption coefficients of 1.4 x 10(4) L/mol/cm. They were completely separated by high-performance liquid chromatography (HPLC) with an RP-Amide C16 column. Cartridges packed with DNPH-coated silica particles (DNPH cartridge) were used for sampling formic acid and aldehydes. Formic acid was physically adsorbed on the silica particles as the first step of the sampling mechanism. Gradual reaction with DNPH followed. Formic acid reacted very slowly with DNPH at room temperature (20 degrees C), but reacted completely at 80 degrees C over 4 h. In field measurements, the sample air was drawn through a DNPH cartridge. After sampling, the cartridges were heated at 80 degrees C for 5 h and extracted with acetonitrile for HPLC analysis. Under these optimized conditions, the LOD is 0.4 ug/m(3) for an air sample collected for 24 h at 100 mL/min (144 L).

SCD1 Inhibition Causes Cancer Cell Death by Depleting Mono-Unsaturated Fatty Acids

PubMed Central

Mason, Paul; Liang, Beirong; Li, Lingyun; Fremgen, Trisha; Murphy, Erin; Quinn, Angela; Madden, Stephen L.; Biemann, Hans-Peter; Wang, Bing; Cohen, Aharon; Komarnitsky, Svetlana; Jancsics, Kate; Hirth, Brad; Cooper, Christopher G. F.; Lee, Edward; Wilson, Sean; Krumbholz, Roy; Schmid, Steven; Xiang, Yibin; Booker, Michael; Lillie, James; Carter, Kara

2012-01-01

Increased metabolism is a requirement for tumor cell proliferation. To understand the dependence of tumor cells on fatty acid metabolism, we evaluated various nodes of the fatty acid synthesis pathway. Using RNAi we have demonstrated that depletion of fatty-acid synthesis pathway enzymes SCD1, FASN, or ACC1 in HCT116 colon cancer cells results in cytotoxicity that is reversible by addition of exogenous fatty acids. This conditional phenotype is most pronounced when SCD1 is depleted. We used this fatty-acid rescue strategy to characterize several small-molecule inhibitors of fatty acid synthesis, including identification of TOFA as a potent SCD1 inhibitor, representing a previously undescribed activity for this compound. Reference FASN and ACC inhibitors show cytotoxicity that is less pronounced than that of TOFA, and fatty-acid rescue profiles consistent with their proposed enzyme targets. Two reference SCD1 inhibitors show low-nanomolar cytotoxicity that is offset by at least two orders of magnitude by exogenous oleate. One of these inhibitors slows growth of HCT116 xenograft tumors. Our data outline an effective strategy for interrogation of on-mechanism potency and pathway-node-specificity of fatty acid synthesis inhibitors, establish an unambiguous link between fatty acid synthesis and cancer cell survival, and point toward SCD1 as a key target in this pathway. PMID:22457791

Method for the production of dicarboxylic acids

DOEpatents

Nghiem, N.P.; Donnelly, M.; Millard, C.S.; Stols, L.

1999-02-09

The present invention is an economical fermentation method for the production of carboxylic acids comprising the steps of (a) inoculating a medium having a carbon source with a carboxylic acid-producing organism; (b) incubating the carboxylic acid-producing organism in an aerobic atmosphere to promote rapid growth of the organism thereby increasing the biomass of the organism; (c) controllably releasing oxygen to maintain the aerobic atmosphere; (d) controllably feeding the organism having increased biomass with a solution containing the carbon source to maintain the concentration of the carbon source within the medium of about 0.5 g/l up to about 1 g/l; (e) depriving the aerobic atmosphere of oxygen to produce an anaerobic atmosphere to cause the organism to undergo anaerobic metabolism; (f) controllably feeding the organism having increased biomass a solution containing the carbon source to maintain the concentration of the carbon source within the medium of {>=}1 g/l; and (g) converting the carbon source to carboxylic acids using the anaerobic metabolism of the organism. 7 figs.

Method for the production of dicarboxylic acids

DOEpatents

Nghiem, Nhuan Phu; Donnelly, Mark; Millard, Cynthia S.; Stols, Lucy

1999-01-01

The present invention is an economical fermentation method for the production of carboxylic acids comprising the steps of a) inoculating a medium having a carbon source with a carboxylic acid-producing organism; b) incubating the carboxylic acid-producing organism in an aerobic atmosphere to promote rapid growth of the organism thereby increasing the biomass of the organism; c) controllably releasing oxygen to maintain the aerobic atmosphere; d) controllably feeding the organism having increased biomass with a solution containing the carbon source to maintain the concentration of the carbon source within the medium of about 0.5 g/L up to about 1 g/L; e) depriving the aerobic atmosphere of oxygen to produce an anaerobic atmosphere to cause the organism to undergo anaerobic metabolism; f) controllably feeding the organism having increased biomass a solution containing the carbon source to maintain the concentration of the carbon source within the medium of .gtoreq.1 g/L; and g) converting the carbon source to carboxylic acids using the anaerobic metabolism of the organism.

Tomato SlERF.A1, SlERF.B4, SlERF.C3 and SlERF.A3, Members of B3 Group of ERF Family, Are Required for Resistance to Botrytis cinerea

PubMed Central

Ouyang, Zhigang; Liu, Shixia; Huang, Lihong; Hong, Yongbo; Li, Xiaohui; Huang, Lei; Zhang, Yafen; Zhang, Huijuan; Li, Dayong; Song, Fengming

2016-01-01

The Ethylene-Responsive Factors (ERFs) comprise a large family of transcriptional factors that play critical roles in plant immunity. Gray mold disease caused by Botrytis cinerea, a typical necrotrophic fungal pathogen, is the serious disease that threatens tomato production worldwide. However, littler is known about the molecular mechanism regulating the immunity to B. cinerea in tomato. In the present study, virus-induced gene silencing (VIGS)-based functional analyses of 18 members of B3 group (also called Group IX) in tomato ERF family were performed to identify putative ERFs that are involved in disease resistance against B. cinerea. VIGS-based silencing of either SlERF.B1 or SlERF.C2 had lethal effect while silencing of SlERF.A3 (Pit4) significantly suppressed vegetative growth of tomato plants. Importantly, silencing of SlERF.A1, SlERF.A3, SlERF.B4, or SlERF.C3 resulted in increased susceptibility to B. cinerea, attenuated the B. cinerea-induced expression of jasmonic acid/ethylene-mediated signaling responsive defense genes and promoted the B. cinerea-induced H2O2 accumulation. However, silencing of SlERF.A3 also decreased the resistance against Pseudomonas syringae pv. tomato (Pst) DC3000 but silencing of SlERF.A1, SlERF.B4 or SlERF.C3 did not affect the resistance to this bacterial pathogen. Expression of SlERF.A1, SlERF.A3, SlERF.B4, or SlERF.C3 was induced by B. cinerea and by defense signaling hormones such as salicylic acid, methyl jasmonate, and 1-aminocyclopropane-1-carboxylic acid (an ethylene precursor). SlERF.A1, SlERF.B4, SlERF.C3, and SlERF.A3 proteins were found to localize in nucleus of cells and possess transactivation activity in yeasts. These data suggest that SlERF.A1, SlERF.B4, and SlERF.C3, three previously uncharacterized ERFs in B3 group, and SlERF.A3, a previously identified ERF with function in immunity to Pst DC3000, play important roles in resistance against B. cinerea in tomato. PMID:28083004

Structural environments of carboxyl groups in natural organic molecules from terrestrial systems. Part 1: Infrared spectroscopy

NASA Astrophysics Data System (ADS)

Hay, Michael B.; Myneni, Satish C. B.

2007-07-01

Carboxyls play an important role in the chemistry of natural organic molecules (NOM) in the environment, and their behavior is dependent on local structural environment within the macromolecule. We studied the structural environments of carboxyl groups in dissolved NOM from the Pine Barrens (New Jersey, USA), and IHSS NOM isolates from soils and river waters using attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy. It is well established that the energies of the asymmetric stretching vibrations of the carboxylate anion (COO -) are sensitive to the structural environment of the carboxyl group. These energies were compiled from previous infrared studies on small organic acids for a wide variety of carboxyl structural environments and compared with the carboxyl spectral features of the NOM samples. We found that the asymmetric stretching peaks for all NOM samples occur within a narrow range centered at 1578 cm -1, suggesting that all NOM samples examined primarily contain very similar carboxyl structures, independent of sample source and isolation techniques employed. The small aliphatic acids containing hydroxyl (e.g., D-lactate, gluconate), ether/ester (methoxyacetate, acetoxyacetate), and carboxylate (malonate) substitutions on the α-carbon, and the aromatic acids salicylate ( ortho-OH) and furancarboxylate ( O-heterocycle), exhibit strong overlap with the NOM range, indicating that similar structures may be common in NOM. The width of the asymmetric peak suggests that the structural heterogeneity among the predominant carboxyl configurations in NOM is small. Changes in peak area with pH at energies distant from the peak at 1578 cm -1, however, may be indicative of a small fraction of other aromatic carboxyls and aliphatic structures lacking α-substitution. This information is important in understanding NOM-metal and mineral-surface complexation, and in building appropriate structural and mechanistic models of humic materials.

Synthesis of carboxylic acids, esters, alcohols and ethers containing a tetrahydropyran ring derived from 6-methyl-5-hepten-2-one.

PubMed

Hanzawa, Yohko; Hashimoto, Kahoko; Kasashima, Yoshio; Takahashi, Yoshiko; Mino, Takashi; Sakamoto, Masami; Fujita, Tsutomu

2012-01-01

3-hydroxy acids, 3-hydroxy-3,7-dimethyloct-6-enoic acid (1) and 3-hydroxy-2,2,3,7-tetramethyloct-6-enoic acid (2), were prepared from 6-methyl-5-hepten-2-one, and they were subsequently used to prepare (2,6,6-trimethyltetrahydropyran-2-yl)acetic acid (3) and 2-methyl-2-(2,6,6-trimethyltetrahydropyran-2-yl)propanoic acid (4), respectively, via cyclization with an acidic catalyst such as boron trifluoride diethyl etherate or iodine. The reaction of carboxylic acids 3 and 4 with alcohols, including methanol, ethanol, and 1-propanol, produced the corresponding methyl, ethyl, and propyl esters, which all contained a tetrahydropyran ring. Reduction of carboxylic acids 3 and 4 afforded the corresponding alcohols. Subsequent reactions of these alcohols with several acyl chlorides produced novel esters. The alcohols also reacted with methyl iodide and sodium hydride to provide novel ethers. A one-pot cyclization-esterification of 1 to produce esters containing a tetrahydropyran ring, using iodine as a catalyst, was also investigated.

1-Azaniumylcyclobutane-1-carboxylate monohydrate

NASA Technical Reports Server (NTRS)

Butcher, Ray J.; Brewer, Greg; Burton, Aaron S.; Dworkin, Jason

2014-01-01

In the title compound, C5H9NO2H2O, the amino acid is in the usual zwitterionic form involving the carboxylate group. The cyclobutane backbone of the amino acid is disordered over two conformations, with occupancies of 0.882 (7) and0.118 (7). In the crystal, NH O and OH O hydrogen bonds link the zwitterions [with the water molecule involved as both acceptor (with the NH3+) and donor (through a single carboxylate O from two different aminocyclobutane carboxylatemoities)], resulting in a two-dimensional layered structure lying parallel to (100).

Rhizospheric Bacterial Strain Brevibacterium casei MH8a Colonizes Plant Tissues and Enhances Cd, Zn, Cu Phytoextraction by White Mustard.

PubMed

Płociniczak, Tomasz; Sinkkonen, Aki; Romantschuk, Martin; Sułowicz, Sławomir; Piotrowska-Seget, Zofia

2016-01-01

Environmental pollution by heavy metals has become a serious problem in the world. Phytoextraction, which is one of the plant-based technologies, has attracted the most attention for the bioremediation of soils polluted with these contaminants. The aim of this study was to determine whether the multiple-tolerant bacterium, Brevibacterium casei MH8a isolated from the heavy metal-contaminated rhizosphere soil of Sinapis alba L., is able to promote plant growth and enhance Cd, Zn, and Cu uptake by white mustard under laboratory conditions. Additionally, the ability of the rifampicin-resistant spontaneous mutant of MH8a to colonize plant tissues and its mechanisms of plant growth promotion were also examined. In order to assess the ecological consequences of bioaugmentation on autochthonous bacteria, the phospholipid fatty acid (PLFA) analysis was used. The MH8a strain exhibited the ability to produce ammonia, 1-amino-cyclopropane-1-carboxylic acid deaminase, indole 3-acetic acid and HCN but was not able to solubilize inorganic phosphate and produce siderophores. Introduction of MH8a into soil significantly increased S. alba biomass and the accumulation of Cd (208%), Zn (86%), and Cu (39%) in plant shoots in comparison with those grown in non-inoculated soil. Introduced into the soil, MH8a was able to enter the plant and was found in the roots and leaves of inoculated plants thus indicating its endophytic features. PLFA analysis revealed that the MH8a that was introduced into soil had a temporary influence on the structure of the autochthonous bacterial communities. The plant growth-promoting features of the MH8a strain and its ability to enhance the metal uptake by white mustard and its long-term survival in soil as well as its temporary impact on autochthonous microorganisms make the strain a suitable candidate for the promotion of plant growth and the efficiency of phytoextraction.

Rhizospheric Bacterial Strain Brevibacterium casei MH8a Colonizes Plant Tissues and Enhances Cd, Zn, Cu Phytoextraction by White Mustard

PubMed Central

Płociniczak, Tomasz; Sinkkonen, Aki; Romantschuk, Martin; Sułowicz, Sławomir; Piotrowska-Seget, Zofia

2016-01-01

Environmental pollution by heavy metals has become a serious problem in the world. Phytoextraction, which is one of the plant-based technologies, has attracted the most attention for the bioremediation of soils polluted with these contaminants. The aim of this study was to determine whether the multiple-tolerant bacterium, Brevibacterium casei MH8a isolated from the heavy metal-contaminated rhizosphere soil of Sinapis alba L., is able to promote plant growth and enhance Cd, Zn, and Cu uptake by white mustard under laboratory conditions. Additionally, the ability of the rifampicin-resistant spontaneous mutant of MH8a to colonize plant tissues and its mechanisms of plant growth promotion were also examined. In order to assess the ecological consequences of bioaugmentation on autochthonous bacteria, the phospholipid fatty acid (PLFA) analysis was used. The MH8a strain exhibited the ability to produce ammonia, 1-amino-cyclopropane-1-carboxylic acid deaminase, indole 3-acetic acid and HCN but was not able to solubilize inorganic phosphate and produce siderophores. Introduction of MH8a into soil significantly increased S. alba biomass and the accumulation of Cd (208%), Zn (86%), and Cu (39%) in plant shoots in comparison with those grown in non-inoculated soil. Introduced into the soil, MH8a was able to enter the plant and was found in the roots and leaves of inoculated plants thus indicating its endophytic features. PLFA analysis revealed that the MH8a that was introduced into soil had a temporary influence on the structure of the autochthonous bacterial communities. The plant growth-promoting features of the MH8a strain and its ability to enhance the metal uptake by white mustard and its long-term survival in soil as well as its temporary impact on autochthonous microorganisms make the strain a suitable candidate for the promotion of plant growth and the efficiency of phytoextraction. PMID:26909087

Ethylene Inhibits Root Elongation during Alkaline Stress through AUXIN1 and Associated Changes in Auxin Accumulation.

PubMed

Li, Juan; Xu, Heng-Hao; Liu, Wen-Cheng; Zhang, Xiao-Wei; Lu, Ying-Tang

2015-08-01

Soil alkalinity causes major reductions in yield and quality of crops worldwide. The plant root is the first organ sensing soil alkalinity, which results in shorter primary roots. However, the mechanism underlying alkaline stress-mediated inhibition of root elongation remains to be further elucidated. Here, we report that alkaline conditions inhibit primary root elongation of Arabidopsis (Arabidopsis thaliana) seedlings by reducing cell division potential in the meristem zones and that ethylene signaling affects this process. The ethylene perception antagonist silver (Ag(+)) alleviated the inhibition of root elongation by alkaline stress. Moreover, the ethylene signaling mutants ethylene response1-3 (etr1-3), ethylene insensitive2 (ein2), and ein3-1 showed less reduction in root length under alkaline conditions, indicating a reduced sensitivity to alkalinity. Ethylene biosynthesis also was found to play a role in alkaline stress-mediated root inhibition; the ethylene overproducer1-1 mutant, which overproduces ethylene because of increased stability of 1-AMINOCYCLOPROPANE-1-CARBOXYLIC ACID SYNTHASE5, was hypersensitive to alkaline stress. In addition, the ethylene biosynthesis inhibitor cobalt (Co(2+)) suppressed alkaline stress-mediated inhibition of root elongation. We further found that alkaline stress caused an increase in auxin levels by promoting expression of auxin biosynthesis-related genes, but the increase in auxin levels was reduced in the roots of the etr1-3 and ein3-1 mutants and in Ag(+)/Co(2+)-treated wild-type plants. Additional genetic and physiological data showed that AUXIN1 (AUX1) was involved in alkaline stress-mediated inhibition of root elongation. Taken together, our results reveal that ethylene modulates alkaline stress-mediated inhibition of root growth by increasing auxin accumulation by stimulating the expression of AUX1 and auxin biosynthesis-related genes. © 2015 American Society of Plant Biologists. All Rights Reserved.

Aromatic Prenylation in Phenazine Biosynthesis

PubMed Central

Saleh, Orwah; Gust, Bertolt; Boll, Björn; Fiedler, Hans-Peter; Heide, Lutz

2009-01-01

The bacterium Streptomyces anulatus 9663, isolated from the intestine of different arthropods, produces prenylated derivatives of phenazine 1-carboxylic acid. From this organism, we have identified the prenyltransferase gene ppzP. ppzP resides in a gene cluster containing orthologs of all genes known to be involved in phenazine 1-carboxylic acid biosynthesis in Pseudomonas strains as well as genes for the six enzymes required to generate dimethylallyl diphosphate via the mevalonate pathway. This is the first complete gene cluster of a phenazine natural compound from streptomycetes. Heterologous expression of this cluster in Streptomyces coelicolor M512 resulted in the formation of prenylated derivatives of phenazine 1-carboxylic acid. After inactivation of ppzP, only nonprenylated phenazine 1-carboxylic acid was formed. Cloning, overexpression, and purification of PpzP resulted in a 37-kDa soluble protein, which was identified as a 5,10-dihydrophenazine 1-carboxylate dimethylallyltransferase, forming a C–C bond between C-1 of the isoprenoid substrate and C-9 of the aromatic substrate. In contrast to many other prenyltransferases, the reaction of PpzP is independent of the presence of magnesium or other divalent cations. The Km value for dimethylallyl diphosphate was determined as 116 μm. For dihydro-PCA, half-maximal velocity was observed at 35 μm. Kcat was calculated as 0.435 s-1. PpzP shows obvious sequence similarity to a recently discovered family of prenyltransferases with aromatic substrates, the ABBA prenyltransferases. The present finding extends the substrate range of this family, previously limited to phenolic compounds, to include also phenazine derivatives. PMID:19339241

Indium-Catalyzed Reductive Dithioacetalization of Carboxylic Acids with Dithiols: Scope, Limitations, and Application to Oxidative Desulfurization.

PubMed

Nishino, Kota; Minato, Kohei; Miyazaki, Takahiro; Ogiwara, Yohei; Sakai, Norio

2017-04-07

In this study an InI 3 -TMDS (1,1,3,3-tetramethyldisiloxane) reducing system effectively catalyzed the reductive dithioacetalization of a variety of aromatic and aliphatic carboxylic acids with 1,2-ethanedithiol or 1,3-propanedithiol leading to the one-pot preparation of either 1,3-dithiolane derivatives or a 1,3-dithiane derivative. Also, the intact indium catalyst continuously catalyzed the subsequent oxidative desulfurization of an in situ formed 1,3-dithiolane derivative, which led to the preparation of the corresponding aldehydes.

Polyamine-induced modulation of genes involved in ethylene biosynthesis and signalling pathways and nitric oxide production during olive mature fruit abscission

PubMed Central

Parra-Lobato, Maria C.; Gomez-Jimenez, Maria C.

2011-01-01

After fruit ripening, many fruit-tree species undergo massive natural fruit abscission. Olive (Olea europaea L.) is a stone-fruit with cultivars such as Picual (PIC) and Arbequina (ARB) which differ in mature fruit abscission potential. Ethylene (ET) is associated with abscission, but its role during mature fruit abscission remains largely uncharacterized. The present study investigates the possible roles of ET and polyamine (PA) during mature fruit abscission by modulating genes involved in the ET signalling and biosynthesis pathways in the abscission zone (AZ) of both cultivars. Five ET-related genes (OeACS2, OeACO2, OeCTR1, OeERS1, and OeEIL2) were isolated in the AZ and adjacent cells (AZ–AC), and their expression in various olive organs and during mature fruit abscission, in relation to interactions between ET and PA and the expression induction of these genes, was determined. OeACS2, OeACO2, and OeEIL2 were found to be the only genes that were up-regulated in association with mature fruit abscission. Using the inhibition of ET and PA biosynthesis, it is demonstrated that OeACS2 and OeEIL2 expression are under the negative control of PA while ET induces their expression in AZ–AC. Furthermore, mature fruit abscission depressed nitric oxide (NO) production present mainly in the epidermal cells and xylem of the AZ. Also, NO production was differentially responsive to ET, PA, and different inhibitors. Taken together, the results indicate that PA-dependent ET signalling and biosynthesis pathways participate, at least partially, during mature fruit abscission, and that endogenous NO and 1-aminocyclopropane-1-carboxylic acid maintain an inverse correlation, suggesting an antagonistic action of NO and ET in abscission signalling. PMID:21633085

Chemiluminescence of Secondary Peroxyesters.

DTIC Science & Technology

1980-11-14

phenylethylperoxybenzoates was investiqlated. Thermolysis in benzene gives acetophenone and the corresponding carboxYlic acid . The study of the reactiol...these compounds undergo unimolecular thermolysis to qenerate the appropriate carboxylic acid add carbonyl compound; eq. 2. We estimated, using...prepared by reaction of 1 -phenylethyl hydroperoxide with the appropriate activated acid precursor. We prepared the hydroperoxide by two different routes

Inhibition of veratridine-induced delayed inactivation of the voltage-sensitive sodium channel by synthetic analogs of crambescin B.

PubMed

Tsukamoto, Tadaaki; Chiba, Yukie; Nakazaki, Atsuo; Ishikawa, Yuki; Nakane, Yoshiki; Cho, Yuko; Yotsu-Yamashita, Mari; Nishikawa, Toshio; Wakamori, Minoru; Konoki, Keiichi

2017-03-01

Crambescin B carboxylic acid, a synthetic analog of crambescin B, was recently found to inhibit the voltage-sensitive sodium channels (VSSC) in a cell-based assay using neuroblastoma Neuro 2A cells. In the present study, whole-cell patch-clamp recordings were conducted with three heterologously expressed VSSC subtypes, Na v 1.2, Na v 1.6 and Na v 1.7, in a human embryonic kidney cell line HEK293T to further characterize the inhibition of VSSC by crambescin B carboxylic acid. Contrary to the previous observation, crambescin B carboxylic acid did not inhibit peak current evoked by depolarization from the holding potential of -100mV to the test potential of -10mV in the absence or presence of veratridine (VTD). In the presence of VTD, however, crambescin B carboxylic acid diminished VTD-induced sustained and tail currents through the three VSSC subtypes in a dose-dependent manner, whereas TTX inhibited both the peak current and the VTD-induced sustained and tail currents through all subtypes of VSSC tested. We thus concluded that crambescin B carboxylic acid does not block VSSC in a similar manner to TTX but modulate the action of VTD, thereby causing an apparent block of VSSC in the cell-based assay. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dimerization of the Bacterial Biotin Carboxylase Subunit Is Required for Acetyl Coenzyme A Carboxylase Activity In Vivo

PubMed Central

Smith, Alexander C.

2012-01-01

Acetyl coenzyme A (acteyl-CoA) carboxylase (ACC) is the first committed enzyme of the fatty acid synthesis pathway. Escherichia coli ACC is composed of four different proteins. The first enzymatic activity of the ACC complex, biotin carboxylase (BC), catalyzes the carboxylation of the protein-bound biotin moiety of another subunit with bicarbonate in an ATP-dependent reaction. Although BC is found as a dimer in cell extracts and the carboxylase activities of the two subunits of the dimer are interdependent, mutant BC proteins deficient in dimerization are reported to retain appreciable activity in vitro (Y. Shen, C. Y. Chou, G. G. Chang, and L. Tong, Mol. Cell 22:807–818, 2006). However, in vivo BC must interact with the other proteins of the complex, and thus studies of the isolated BC may not reflect the intracellular function of the enzyme. We have tested the abilities of three BC mutant proteins deficient in dimerization to support growth and report that the two BC proteins most deficient in dimerization fail to support growth unless expressed at high levels. In contrast, the wild-type protein supports growth at low expression levels. We conclude that BC must be dimeric to fulfill its physiological function. PMID:22037404

Obesity Drives Th17 Cell Differentiation by Inducing the Lipid Metabolic Kinase, ACC1.

PubMed

Endo, Yusuke; Asou, Hikari K; Matsugae, Nao; Hirahara, Kiyoshi; Shinoda, Kenta; Tumes, Damon J; Tokuyama, Hirotake; Yokote, Koutaro; Nakayama, Toshinori

2015-08-11

Chronic inflammation due to obesity contributes to the development of metabolic diseases, autoimmune diseases, and cancer. Reciprocal interactions between metabolic systems and immune cells have pivotal roles in the pathogenesis of obesity-associated diseases, although the mechanisms regulating obesity-associated inflammatory diseases are still unclear. In the present study, we performed transcriptional profiling of memory phenotype CD4 T cells in high-fat-fed mice and identified acetyl-CoA carboxylase 1 (ACC1, the gene product of Acaca) as an essential regulator of Th17 cell differentiation in vitro and of the pathogenicity of Th17 cells in vivo. ACC1 modulates the DNA binding of RORγt to target genes in differentiating Th17 cells. In addition, we found a strong correlation between IL-17A-producing CD45RO(+)CD4 T cells and the expression of ACACA in obese subjects. Thus, ACC1 confers the appropriate function of RORγt through fatty acid synthesis and regulates the obesity-related pathology of Th17 cells. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

5-Hydroxytryptamine (serotonin)2A receptors in rat anterior cingulate cortex mediate the discriminative stimulus properties of d-lysergic acid diethylamide.

PubMed

Gresch, Paul J; Barrett, Robert J; Sanders-Bush, Elaine; Smith, Randy L

2007-02-01

d-Lysergic acid diethylamide (LSD), an indoleamine hallucinogen, produces profound alterations in mood, thought, and perception in humans. The brain site(s) that mediates the effects of LSD is currently unknown. In this study, we combine the drug discrimination paradigm with intracerebral microinjections to investigate the anatomical localization of the discriminative stimulus of LSD in rats. Based on our previous findings, we targeted the anterior cingulate cortex (ACC) to test its involvement in mediating the discriminative stimulus properties of LSD. Rats were trained to discriminate systemically administered LSD (0.085 mg/kg s.c.) from saline. Following acquisition of the discrimination, bilateral cannulae were implanted into the ACC (AP, +1.2 mm; ML, +/-1.0 mm; DV, -2.0 mm relative to bregma). Rats were tested for their ability to discriminate varying doses of locally infused LSD (0.1875, 0.375, and 0.75 microg/side) or artificial cerebrospinal fluid (n = 3-7). LSD locally infused into ACC dose-dependently substituted for systemically administered LSD, with 0.75 microg/side LSD substituting completely (89% correct). Systemic administration of the selective 5-hydroxytryptamine (serotonin) (5-HT)(2A) receptor antagonist R-(+)-alpha-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenylethyl)]-4-piperidine-methanol (M100907; 0.4 mg/kg) blocked the discriminative cue of LSD (0.375 microg/side) infused into ACC (from 68 to 16% drug lever responding). Furthermore, M100907 (0.5 microg/microl/side) locally infused into ACC completely blocked the stimulus effects of systemic LSD (0.04 mg/kg; from 80 to 12% on the LSD lever). Taken together, these data indicate that 5-HT(2A) receptors in the ACC are a primary target mediating the discriminative stimulus properties of LSD.

Changes in hepatic glucose and lipid metabolism-related parameters in domestic pigeon (Columba livia) during incubation and chick rearing.

PubMed

Wan, X P; Xie, P; Bu, Z; Zou, X T

2018-04-01

This study aimed to evaluate the hepatic glucose and lipid metabolism-related parameters of adult male and female White King pigeons (Columba livia) during incubation and chick rearing. At day 4 (I4), 10 (I10) and 17 (I17) of incubation and day 1 (R1), 7 (R7), 15 (R15) and 25 (R25) of chick rearing, livers were sampled from six pigeons for each sex. Glycogen and fat contents, activities of glycolytic enzymes (hexokinase, HK; 6-phosphofructokinase, 6-PFK), and genes expressions of key enzymes involved in glycolysis (pyruvate kinase, PK; glucokinase, GK), gluconeogenesis (phosphoenolpyruvate carboxykinase cytosolic, PCK1; fructose-1,6-bisphosphatase, FBP1; glucose-6-phosphatase, G6Pase), fatty acid synthesis (fatty acid synthase, FAS; acetyl-CoA carboxylase, ACC) and fatty acid β-oxidation (carnitine palmitoyltransferase 1, CPT1; acyl-CoA 1, ACO) were measured. In male and female pigeon livers, glycogen content and HK activity dramatically increased after I17 and after R1, respectively; expressions of FBP1 and G6Pase genes were maximized at R15; activity of 6-PFK and expressions of PK and CPT1 genes were highest at R7; fat content and expressions of FAS and ACC genes steeply increased from I10 to R1. In females, hepatic expressions of GK and PCK1 genes were greatest at R7 and I17, respectively; however, in males, both of them were maximized at R15. Hepatic expression of ACO gene was significantly enhanced at R1 compared to I17 and R7 in males, whereas it was notably up-regulated at I17 and R7 in females. Furthermore, expressions of PCK1, GK, FAS and ACC genes were in significant relation to fat content in the livers of female pigeons, while fat content in male pigeons was highly correlated with expression of PCK1, ACC, CPT1 and ACO genes. In conclusion, regulations of glucose and lipid metabolic processes were enhanced in parent pigeon livers from terminal phases of incubation to mid phase of chick rearing with sexual effects. © 2017 Blackwell Verlag GmbH.

Occurrence of carboxylic acids in different steps of two drinking-water treatment plants using different disinfectants.

PubMed

Jurado-Sánchez, Beatriz; Ballesteros, Evaristo; Gallego, Mercedes

2014-03-15

The occurrence of 35 aliphatic and aromatic carboxylic acids within two full scale drinking-water treatment plants was evaluated for the first time in this research. At the intake of each plant (raw water), the occurrence of carboxylic acids varied according to the quality of the water source although in both cases 13 acids were detected at average concentrations of 6.9 and 4.7 μg/L (in winter). In the following steps in each treatment plant, the concentration patterns of these compounds differed depending on the type of disinfectant applied. Thus, after disinfection by chloramination, the levels of the acids remained almost constant (average concentration, 6.3 μg/L) and four new acids were formed (butyric, 2-methylbutyric, 3-hydroxybenzoic and 2-nitrobenzoic) at low levels (1.1-5 μg/L). When ozonation/chlorination was used, the total concentration of the carboxylic acids in the raw water sample (4.7 μg/L) increased up to 6 times (average concentration, 26.3 μg/L) after disinfection and 6 new acids (mainly aromatic) were produced at high levels (3.5-100 μg/L). Seasonal variations of the carboxylic acids under study showed that in both plants, maximum levels of all the analytes were reached in the coldest months (autumn and winter), aromatic acids only being found in those seasons. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Pollution characteristics of organic acids in atmospheric particles during haze periods in autumn in Guangzhou].

PubMed

Tan, Ji-hua; Zhao, Jing-ping; Duan, Jing-chun; Ma, Yong-liang; He, Ke-bin; Yang, Fu-mo

2013-05-01

Total suspended particles (TSP), collected during a typical haze period in Guangzhou, were analyzed for the fatty acids (C12-C30) and low molecular weight dicarboxylic acids (C3-C9) using gas chromatography/mass spectrometry (GC/MS). The results showed that the concentration of total fatty and carboxylic acids was pretty high during the haze episode. The ratios of fatty acids and carboxylic acids in haze to those in normal days were 1.9 and 2.5, respectively. During the episode of the increasing pollution, the fatty acids and carboxylic acids at night (653 ng x m(-3)) was higher than that (487 ng x m(-3)) in days. After that, the level of fatty acids and carboxylic acids in days (412 ng x m(-3)) was higher than that (336 ng x m(-3)) at night. In general, the time-series of fatty acids and carboxylic acids was similar to that of the air particle and carbonaceous species, however, the trend of the ratio of fatty acids and carboxylic acids to organic carbon was opposite to that of air particle and carbonaceous species. This ratio decreased with the increase of the concentration of air particle and after the night of 27th, the ratio increased with the decrease in the concentration of air particle. The results showed that haze pollution had a significant inhibitory effect on the enrichment of fatty and carboxylic acids. Based on the ratio of malonate to succinate (C3/C4), it could be found that primary sources contribute more to the atmospheric fatty and carboxylic acids during the autumn haze pollution periods in Guangzhou.

A glutathione S-transferase gene associated with antioxidant properties isolated from Apis cerana cerana

NASA Astrophysics Data System (ADS)

Liu, Shuchang; Liu, Feng; Jia, Haihong; Yan, Yan; Wang, Hongfang; Guo, Xingqi; Xu, Baohua

2016-06-01

Glutathione S-transferases (GSTs) are an important family of multifunctional enzymes in aerobic organisms. They play a crucial role in the detoxification of exogenous compounds, especially insecticides, and protection against oxidative stress. Most previous studies of GSTs in insects have largely focused on their role in insecticide resistance. Here, we isolated a theta class GST gene designated AccGSTT1 from Apis cerana cerana and aimed to explore its antioxidant and antibacterial attributes. Analyses of homology and phylogenetic relationships suggested that the predicted amino acid sequence of AccGSTT1 shares a high level of identity with the other hymenopteran GSTs and that it was conserved during evolution. Quantitative real-time PCR showed that AccGSTT1 is most highly expressed in adult stages and that the expression profile of this gene is significantly altered in response to various abiotic stresses. These results were confirmed using western blot analysis. Additionally, a disc diffusion assay showed that a recombinant AccGSTT1 protein may be roughly capable of inhibiting bacterial growth and that it reduces the resistance of Escherichia coli cells to multiple adverse stresses. Taken together, these data indicate that AccGSTT1 may play an important role in antioxidant processes under adverse stress conditions.

Electrochemistry of Metal Surfaces

DTIC Science & Technology

1990-06-30

i) 3-pyridine carboxylic acid ( nicotinic acid, NA) binds to Pt surfaces through both the nitrogen atom and an oxygen atom of the carboxylate group...formed from aqueous electrolytes at Pt(1l1) electrode surfaces have been compared with the IR and Raman spectra of the unadsorbed compounds in order...vibrational absorptivities between EELS spectra of adsorbed species and IR and Raman spectra of the corresponding unadsorbed compounds (146). Of

Genome Sequence of Sphingomonas wittichii DP58, the First Reported Phenazine-1-Carboxylic Acid-Degrading Strain

PubMed Central

Ma, Zhiwei; Shen, Xuemei; Wang, Wei; Peng, Huasong; Xu, Ping; Zhang, Xuehong

2012-01-01

Sphingomonas wittichii DP58 (CCTCC M 2012027), the first reported phenazine-1-carboxylic acid (PCA)-degrading strain, was isolated from pimiento rhizosphere soils. Here we present a 5.6-Mb assembly of its genome. This sequence would contribute to the elucidation of the molecular mechanism of PCA degradation to improve the antifungal's effectiveness or remove superfluous PCA. PMID:22689229

THERMAL DESORPTION MASS SPECTROMETRIC ANALYSIS OF ORGANIC AEROSOL FORMED FROM REACTIONS OF 1-TETRADECENE AND O3 IN THE PRESENCE OF ALCOHOLS AND CARBOXYLIC ACIDS. (R826235)

EPA Science Inventory

The chemistry of secondary organic aerosol formation from reactions of
1-tetradecene and O₃ in dry air in the presence of excess alcohols
and carboxylic acids was investigated in an environmental chamber using a
thermal desorption particle beam mass spec...

Aristolic Acid Derivatives from the Bark of Antidesma ghaesembilla.

PubMed

Schäfer, Sibylle; Schwaiger, Stefan; Stuppner, Hermann

2017-08-01

Antidesma ghaesembilla is an important medicinal and food plant in many Asian countries. Ten substances could be isolated from the dichloromethane and methanol extract: sitostenone ( 3 ), daucosterol ( 4 ), chavibetol ( 5 ), asperphenamate ( 6 ), protocatechuic acid ( 7 ), vanillic acid-4- O - β -D-glucoside ( 8 ), 1- O - β -D-glucopyranosyl-3- O -methyl-phloroglucinol ( 9 ), and aristolic acid II-8- O - β -D-glucoside ( 10 ), and two new aristolic acid derivatives, 10-amino-5,7-dimethoxy-aristolic acid II (= 6-amino-9,11-dimethoxyphenanthro[3,4- d ]-1,3-dioxole-5-carboxylic acid; 1 ) and 5,7-dimethoxy-aristolochic acid II (= 9,11-dimethoxy-6-nitrophenantro[3,4- d ]-1,3-dioxole-5-carboxylic acid; 2 ). Exposure to humans of some of these compounds is associated with a severe disease today known as aristolochic acid nephropathy. Therefore, the traditional usage of this plant has to be reconsidered carefully. Georg Thieme Verlag KG Stuttgart · New York.

Efficient click chemistry towards fatty acids containing 1,2,3-triazole: Design and synthesis as potential antifungal drugs for Candida albicans.

PubMed

Fu, Nina; Wang, Suiliang; Zhang, Yuqian; Zhang, Caixia; Yang, Dongliang; Weng, Lixing; Zhao, Baomin; Wang, Lianhui

2017-08-18

Candida is an important opportunistic human fungal pathogen. The cis-2-dodecenoic acid (BDSF) showing in vitro activity of against C. albicans growth, germ-tube germination and biofilm formation has been a potential inhibitor for Candida and other fungi. In this study, facile synthetic strategies toward a novel family of BDSF analogue, 1-alkyl-1H-1,2,3-triazole-4-carboxylic acids (ATCs) was developed. The straightforward synthetic method including converting the commercial available alkyl bromide to alkyl azide, consequently with a typical click chemistry method, copper(II) sulfate and sodium ascorbate as catalyst in water to furnish ATCs with mild to good yields. According to antifungal assay, 1-decyl-4,5-dihydro-1H-1,2,3-triazole-4-carboxylic acid (5d) showed antifungal capability slightly better than BDSF. The 1,2,3-triazole unit played a crucial role for the bioactivity of ATCs was also confirmed when compared with two alkyl-aromatic carboxylic acids. Given its simplicity, high antifungal activity, and wide availability of compounds with halide atoms on the end part of the alkyl chains, the method can be extended to develop more excellent ATC drugs for accomplishing the challenges in future antifungal applications. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Luminescent hybrid lanthanide sulfates and lanthanide sulfonate-carboxylates with 1,10-phenanthroline involving in-situ oxidation of 2-mercaptonbenzoic acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhong, Jie-Cen; Wan, Fang; State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002

A series of lanthanide sulfates and lanthanide sulfonate-carboxylates, [Ln{sub 2}(phen){sub 2}(SO{sub 4}){sub 3}(H{sub 2}O){sub 2}]{sub n} (I:Ln=Nd(1a), Sm(1b), Eu(1c), phen=1,10-phenanthroline) and [Ln(phen)(2-SBA)(BZA)]{sub n} (II: Ln=Sm(2a), Eu(2b), Dy(2c), 2-SBA=2-sulfobenzoate, BZA=benzoate) have been hydrothermally synthesized from lanthanide oxide, 2-mercaptonbenzoic acid with phen as auxiliary ligand and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra, TG analyses and luminescence spectroscopy. Interestingly, SO{sub 4}{sup 2−} anions in I came from the in situ deep oxidation of thiol groups of 2-mercaptonbenzoic acid while 2-sulfobenzoate and benzoate ligands in II from the middle oxidation and desulfuration reactions of 2-mercaptonbenzoic acid. Compounds I are organic–inorganic hybridmore » lanthanide sulfates, which have rare one-dimensional column-like structures. Complexes II are binuclear lanthanide sulfonate-carboxylates with 2-sulfobenzoate and benzoate as bridges and 1,10-phenanthroline as terminal. Photoluminescence studies reveal that complexes I and II exhibit strong lanthanide characteristic emission bands in the solid state at room temperature. - Graphical abstract: Lanthanide sulfates and lanthanide sulfonate-carboxylates have been hydrothermally synthesized. Interestingly, sulfate anions, 2-sulfobenzoate and benzoate ligands came from the in situ oxidation and desulfuration reactions of 2-mercaptonbenzoic acid. - Highlights: • In situ oxidation and desulfuration reactions of 2-mercaptonbenzoic acid. • The organic–inorganic hybrid lanthanide sulfates with one-dimensional column-like structure. • The dinuclear lanthanide sulfonate-carboxylates. • The emission spectra exhibit the characteristic transition of {sup 5}D{sub 0}→{sup 7}F{sub J} (J=0–4) of the Eu(III)« less

Application of L-proline derivatives as chiral shift reagents for enantiomeric recognition of carboxylic acids.

PubMed

Naziroglu, Hayriye Nevin; Durmaz, Mustafa; Bozkurt, Selahattin; Sirit, Abdulkadir

2011-07-01

Four proline-derived chiral receptors 5-8 were readily synthesized starting from L-proline. The enantiomeric recognition ability of chiral receptors was examined with a series of carboxylic acids by (1) H NMR spectroscopy. The molar ratio and the association constants of the chiral compounds with each of the enantiomers of guest molecules were determined by using Job plots and a nonlinear least-squares fitting method, respectively. The Job plots indicate that the hosts form 1:1 instantaneous complexes with all guests. The receptors exhibited different chiral recognition abilities toward the enantiomers of racemic guests. Among the chiral receptors used in this study, prolinamide 6 was found to be the best chiral shift reagent and is effective for the determination of the enantiomeric excess of chiral carboxylic acids. Copyright © 2011 Wiley-Liss, Inc.

Formation and High-order Carboxylic Acids (RCOOH) in Interstellar Analogous Ices of Carbon Dioxide (CO2) and Methane(CH4)

NASA Astrophysics Data System (ADS)

Zhu, Cheng; Turner, Andrew M.; Abplanalp, Matthew J.; Kaiser, Ralf I.

2018-01-01

This laboratory study simulated the abiotic formation of carboxylic acids (RCOOH) in interstellar analogous ices of carbon dioxide (CO2) and methane (CH4) at 10 K upon exposure to energetic electrons. The chemical processing of the ices and the subsequent warm-up phase were monitored online and in situ, exploiting Fourier Transform Infrared Spectrometry and quadrupole mass spectrometry. Characteristic absorptions of functional groups of carboxylic acids (RCOOH) were observed in the infrared spectra of the irradiated ice. Two proposed reaction mechanisms replicated the kinetic profiles of the carboxylic acids along with the decay profile of the precursors during the irradiation via hydrocarbon formation, followed by carboxylation and/or through acetic acid along with mass growth processes of the alkyl chain. Mass spectra recorded during the warm-up phase demonstrated that these acids are distributed from acetic acid (CH3COOH) up to decanoic acid (C9H19COOH). High-dose irradiation studies (91 ± 14 eV) converted low-molecular-weight acids such as acetic acid (CH3COOH) and propionic acid (C2H5COOH) to higher-molecular-weight carboxylic acids, compared to low-dose irradiation studies (18 ± 3 eV). The traces of the {{{H}}}2{{C}}= {{C}}({OH}{)}2+ (m/z = 60) fragment—a link to linear carboxylic acids—implied that higher-order acids (C n H2n+1COOH, n ≥ 5) are likely branched, which correlates with the recent analysis of the structures of the monocarboxylic acids in the Murchison meteorite.

Transcription of ethylene perception and biosynthesis genes is altered by putrescine, spermidine and aminoethoxyvinylglycine (AVG) during ripening in peach fruit (Prunus persica).

PubMed

Ziosi, Vanina; Bregoli, Anna Maria; Bonghi, Claudio; Fossati, Tiziana; Biondi, Stefania; Costa, Guglielmo; Torrigiani, Patrizia

2006-01-01

The time course of ethylene biosynthesis and perception was investigated in ripening peach fruit (Prunus persica) following treatments with the polyamines putrescine (Pu) and spermidine (Sd), and with aminoethoxyvinylglycine (AVG). Fruit treatments were performed in planta. Ethylene production was measured by gas chromatography, and polyamine content by high-performance liquid chromatography; expression analyses were performed by Northern blot or real-time polymerase chain reaction. Differential increases in the endogenous polyamine pool in the epicarp and mesocarp were induced by treatments; in both cases, ethylene production, fruit softening and abscission were greatly inhibited. The rise in 1-aminocyclopropane-1-carboxylate oxidase (PpACO1) mRNA was counteracted and delayed in polyamine-treated fruit, whereas transcript abundance of ethylene receptors PpETR1 (ethylene receptor 1) and PpERS1 (ethylene sensor 1) was enhanced at harvest. Transcript abundance of arginine decarboxylase (ADC) and S-adenosylmethionine decarboxylase (SAMDC) was transiently reduced in both the epicarp and mesocarp. AVG, here taken as a positive control, exerted highly comparable effects to those of Pu and Sd. Thus, in peach fruit, increasing the endogenous polyamine pool in the epicarp or in the mesocarp strongly interfered, both at a biochemical and at a biomolecular level, with the temporal evolution of the ripening syndrome.

Reduced heart size and increased myocardial fuel substrate oxidation in ACC2 mutant mice

PubMed Central

Essop, M. Faadiel; Camp, Heidi S.; Choi, Cheol Soo; Sharma, Saumya; Fryer, Ryan M.; Reinhart, Glenn A.; Guthrie, Patrick H.; Bentebibel, Assia; Gu, Zeiwei; Shulman, Gerald I.; Taegtmeyer, Heinrich; Wakil, Salih J.; Abu-Elheiga, Lutfi

2008-01-01

The cardiac-enriched isoform of acetyl-CoA carboxylase (ACC2) is a key regulator of mitochondrial fatty acid (FA) uptake via carnitine palmitoyltransferase 1 (CPT1). To test the hypothesis that oxidative metabolism is upregulated in hearts from animals lacking ACC2 (employing a transgenic Acc2-mutant mouse), we assessed cardiac function in vivo and determined rates of myocardial substrate oxidation ex vivo. When examined by echocardiography, there was no difference in systolic function, but left ventricular mass of the Acc2-mutant (MUT) mouse was significantly reduced (∼25%) compared with wild-types (WT). Reduced activation of the mammalian target of rapamycin (mTOR) and its downstream target p70S6K was found in MUT hearts. Exogenous oxidation rates of oleate were increased ∼22%, and, unexpectedly, exogenous glucose oxidation rates were also increased in MUT hearts. Using a hyperinsulinemic-euglycemic clamp, we found that glucose uptake in MUT hearts was increased by ∼83%. Myocardial triglyceride levels were significantly reduced in MUT vs. WT while glycogen content was the same. In parallel, transcript levels of PPARα and its target genes, pyruvate dehydrogenase kinase-4 (PDK-4), malonyl-CoA decarboxylase (MCD), and mCPT1, were downregulated in MUT mice. In summary, we report that 1) Acc2-mutant hearts exhibit a marked preference for the oxidation of both glucose and FAs coupled with greater utilization of endogenous fuel substrates (triglycerides), 2) attenuated mTOR signaling may result in reduced heart sizes observed in Acc2-mutant mice, and 3) Acc2-mutant hearts displayed normal functional parameters despite a significant decrease in size. PMID:18487439

Synthesis and antiprotozoan evaluation of new alkyl-linked bis(2-thioxo-[1,3,5]thiadiazinan-3-yl) carboxylic acids.

PubMed

Coro, Julieta; Pérez, Rolando; Rodríguez, Hortensia; Suárez, Margarita; Vega, Celeste; Rolón, Miriam; Montero, David; Nogal, Juan José; Gómez-Barrio, Alicia

2005-05-16

Two new series of several alkyl-linked bis(2-thioxo-[1,3,5]thiadiazinan-3-yl) carboxylic acids were synthesized in a two step procedure from the corresponding alkyl bis-dithiocarbamic salt intermediary. The novel compounds were evaluated for their activity in vitro against Trypanosoma cruzi strain CL (clone CL B5) and Trichomonas vaginalis strain JH 31A.

Reactive Capture of Gold Nanoparticles by Strongly Physisorbed Monolayers on Graphite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wei, Xiaoliang; Tong, Wenjun; Fidler, Vlastimil

2012-12-01

Anthracene Diels Alder adducts (DAa) bearing two long side chains (H-(CH2)22O(CH2)6OCH2-) at the 1- and 5-positions form self-assembled monolayers (SAMs) at the phenyloctane - highly oriented pyrolytic graphite (HOPG) interface. The long DAa side chains promote strong physisorption of the monolayer to HOPG and maintain the monolayer morphology upon rinsing or incubation in ethanol and air-drying of the substrate. Incorporating a carboxylic acid group on the DAa core enables capture of 1 - 4 nm diameter gold nanoparticles (AuNP) provided (i) the monolayer containing DAa-carboxylic acids is treated with Cu2+ ions and (ii) the organic coating on the AuNP containsmore » carboxylic acids (11-mercaptoundecanoic acid, MUA-AuNP). AuNP capture by the monolayer proceeds with formation of Cu2+ - carboxylate coordination complexes. The captured AuNP appear as mono- and multi-layered clusters at high coverage on HOPG. The surface density of the captured AuNPs can be adjusted from AuNP multi-layers to isolated AuNPs by varying incubation times, MUA-AuNP concentration, the number density of carboxylic acids in the monolayer, the number of MUA per AuNP, and the post-incubation treatments.« less

Proof of concept of a "greener" protein purification/enrichment method based on carboxylate-terminated carbosilane dendrimer-protein interactions.

PubMed

González-García, Estefanía; Maly, Marek; de la Mata, Francisco Javier; Gómez, Rafael; Marina, María Luisa; García, María Concepción

2016-11-01

Protein sample preparation is a critical and an unsustainable step since it involves the use of tedious methods that usually require high amount of solvents. The development of new materials offers additional opportunities in protein sample preparation. This work explores, for the first time, the potential application of carboxylate-terminated carbosilane dendrimers to the purification/enrichment of proteins. Studies on dendrimer binding to proteins, based on protein fluorescence intensity and emission wavelengths measurements, demonstrated the interaction between carboxylate-terminated carbosilane dendrimers and proteins at all tested pH levels. Interactions were greatly affected by the protein itself, pH, and dendrimer concentration and generation. Especially interesting was the interaction at acidic pH since it resulted in a significant protein precipitation. Dendrimer-protein interactions were modeled observing stable complexes for all proteins. Carboxylate-terminated carbosilane dendrimers at acidic pH were successfully used in the purification/enrichment of proteins extracted from a complex sample. Graphical Abstract Images showing the growing turbidity of solutions containing a mixture of proteins (lysozyme, myoglobin, and BSA) at different protein:dendrimer ratios (1:0, 1:1, 1:8, and 1:20) at acidic pH and SDS-PAGE profiles of the corresponsing supernatants. Comparison of SDS-PAGE profiles for the pellets obtained during the purification of proteins present in a complex sample using a conventional "no-clean" method based on acetone precipitation and the proposed "greener" method using carboxylate-terminated carbosilane dendrimer at a 1:20 protein:dendrimer ratio.

Short Carboxylic Acid-Carboxylate Hydrogen Bonds Can Have Fully Localized Protons.

PubMed

Lin, Jiusheng; Pozharski, Edwin; Wilson, Mark A

2017-01-17

Short hydrogen bonds (H-bonds) have been proposed to play key functional roles in several proteins. The location of the proton in short H-bonds is of central importance, as proton delocalization is a defining feature of low-barrier hydrogen bonds (LBHBs). Experimentally determining proton location in H-bonds is challenging. Here, bond length analysis of atomic (1.15-0.98 Å) resolution X-ray crystal structures of the human protein DJ-1 and its bacterial homologue, YajL, was used to determine the protonation states of H-bonded carboxylic acids. DJ-1 contains a buried, dimer-spanning 2.49 Å H-bond between Glu15 and Asp24 that satisfies standard donor-acceptor distance criteria for a LBHB. Bond length analysis indicates that the proton is localized on Asp24, excluding a LBHB at this location. However, similar analysis of the Escherichia coli homologue YajL shows both residues may be protonated at the H-bonded oxygen atoms, potentially consistent with a LBHB. A Protein Data Bank-wide screen identifies candidate carboxylic acid H-bonds in approximately 14% of proteins, which are typically short [⟨d O-O ⟩ = 2.542(2) Å]. Chemically similar H-bonds between hydroxylated residues (Ser/Thr/Tyr) and carboxylates show a trend of lengthening O-O distance with increasing H-bond donor pK a . This trend suggests that conventional electronic effects provide an adequate explanation for short, charge-assisted carboxylic acid-carboxylate H-bonds in proteins, without the need to invoke LBHBs in general. This study demonstrates that bond length analysis of atomic resolution X-ray crystal structures provides a useful experimental test of certain candidate LBHBs.

Petroleum degradation by endophytic Streptomyces spp. isolated from plants grown in contaminated soil of southern Algeria.

PubMed

Baoune, Hafida; Ould El Hadj-Khelil, Aminata; Pucci, Graciela; Sineli, Pedro; Loucif, Lotfi; Polti, Marta Alejandra

2018-01-01

Petroleum hydrocarbons are well known by their high toxicity and recalcitrant properties. Their increasing utilization around worldwide led to environmental contamination. Phytoremediation using plant-associated microbe is an interesting approach for petroleum degradation and actinobacteria have a great potential for that. For this purpose, our study aimed to isolate, characterize, and assess the ability of endophytic actinobacteria to degrade crude petroleum, as well as to produce plant growth promoting traits. Seventeen endophytic actinobacteria were isolated from roots of plants grown naturally in sandy contaminated soil. Among them, six isolates were selected on the basis of their tolerance to petroleum on solid minimal medium and characterized by 16S rDNA gene sequencing. All petroleum-tolerant isolates belonged to the Streptomyces genus. Determination by crude oil degradation by gas chromatorgraph-flame ionization detector revealed that five strains could use petroleum as sole carbon and energy source and the petroleum removal achieved up to 98% after 7 days of incubation. These isolates displayed an important role in the degradation of the n-alkanes (C 6 -C 30 ), aromatic and polycyclic aromatic hydrocarbons. All strains showed a wide range of plant growth promoting features such as siderophores, phosphate solubilization, 1-aminocyclopropane-1-carboxylate deaminase, nitrogen fixation and indole-3-acetic acid production as well as biosurfactant production. This is the first study highlighting the petroleum degradation ability and plant growth promoting attributes of endophytic Streptomyces. The finding suggests that the endophytic actinobacteria isolated are promising candidates for improving phytoremediation efficiency of petroleum contaminated soil. Copyright © 2017 Elsevier Inc. All rights reserved.

Streptomyces cameroonensis sp. nov., a Geldanamycin Producer That Promotes Theobroma cacao Growth.

PubMed

Boudjeko, Thaddée; Tchinda, Romaric Armel Mouafo; Zitouni, Mina; Nana, Joëlle Aimée Vera Tchatchou; Lerat, Sylvain; Beaulieu, Carole

2017-03-31

The taxonomy of an actinobacterial strain, designated JJY4 T , was established using a polyphasic approach. JJY4 T was isolated from the rhizosphere of Chromolaena odorata in Yaoundé (Cameroon) during a project for the selection of biological control agents. Strain JJY4 T exhibited antimicrobial activities against bacteria, fungi, and oomycetes. Strain JJY4 T also exhibited the traits of plant growth-promoting rhizobacteria such as the solubilization of inorganic phosphate, production of siderophores and indole-3-acetic acid, and 1-aminocyclopropane-1-carboxylate deaminase activity. In planta assays performed on cocoa plantlets confirmed that strain JJY4 T exhibited strong abilities to promote plant growth and protect against Phytophthora megakarya, the main causal agent of cocoa pod rot. The formation of rugose-ornamented spores in spiral spore chains by strain JJY4 T is a typical feature of members found in the Streptomyces violaceusniger clade and, similar to some members of the clade, strain JJY4 T produces geldanamycin. A phylogenetic analysis based on 16S rRNA gene sequences confirmed this classification and suggests that strain JJY4 T be added to the subclade constituted of the type strains Streptomyces malaysiensis DSM 41697 T and Streptomyces samsunensis DSM 42010 T . However, DNA-DNA relatedness and physiological characteristics allowed for the differentiation of strain JJY4 T from its closest phylogenetic relatives. Based on these results, strain JJY4 T (=NRRL B-65369, =NBRC 112705) appears to represent a novel species in the S. violaceusniger clade for which the proposed name is Streptomyces cameroonensis sp. nov.

Biochemical and Molecular Mechanisms of Plant-Microbe-Metal Interactions: Relevance for Phytoremediation

PubMed Central

Ma, Ying; Oliveira, Rui S.; Freitas, Helena; Zhang, Chang

2016-01-01

Plants and microbes coexist or compete for survival and their cohesive interactions play a vital role in adapting to metalliferous environments, and can thus be explored to improve microbe-assisted phytoremediation. Plant root exudates are useful nutrient and energy sources for soil microorganisms, with whom they establish intricate communication systems. Some beneficial bacteria and fungi, acting as plant growth promoting microorganisms (PGPMs), may alleviate metal phytotoxicity and stimulate plant growth indirectly via the induction of defense mechanisms against phytopathogens, and/or directly through the solubilization of mineral nutrients (nitrogen, phosphate, potassium, iron, etc.), production of plant growth promoting substances (e.g., phytohormones), and secretion of specific enzymes (e.g., 1-aminocyclopropane-1-carboxylate deaminase). PGPM can also change metal bioavailability in soil through various mechanisms such as acidification, precipitation, chelation, complexation, and redox reactions. This review presents the recent advances and applications made hitherto in understanding the biochemical and molecular mechanisms of plant–microbe interactions and their role in the major processes involved in phytoremediation, such as heavy metal detoxification, mobilization, immobilization, transformation, transport, and distribution. PMID:27446148

Tunable polymeric sorbent materials for fractionation of model naphthenates.

PubMed

Mohamed, Mohamed H; Wilson, Lee D; Headley, John V

2013-04-04

The sorption properties are reported for several examples of single-component carboxylic acids representing naphthenic acids (NAs) with β-cyclodextrin (β-CD) based polyurethane sorbents. Seven single-component examples of NAs were chosen with variable z values, carbon number, and chemical structure as follows: 2-hexyldecanoic acid (z = 0 and C = 16; S1), n-caprylic acid (z = 0 and C = 8; S2), trans-4-pentylcyclohexanecarboxylic acid (z = -2 and C = 12; S3), 4-methylcyclohexanecarboxylic acid (z = -2 and C = 8; S4), dicyclohexylacetic acid (z = -4; C = 14; S5), 4-pentylbicyclo[2.2.2]octane-1-carboxylic acid (z = -4; C = 14; S6), and lithocholic acid (z = -6; C = 24; S7). The copolymer sorbents were synthesized at three relative β-CD:diisocyanate mole ratios (i.e., 1:1, 1:2, and 1:3) using 4,4'-dicyclohexylmethane diisocyanate (CDI) and 4,4'-diphenylmethane diisocyanate (MDI). The sorption properties of the copolymer sorbents were characterized using equilibrium sorption isotherms in aqueous solution at pH 9.00 with electrospray ionization mass spectrometry. The equilibrium fraction of the unbound carboxylate anions was monitored in the aqueous phase. The sorption properties of the copolymer sorbents (i.e., Qm) were obtained from the Sips isotherm model. The Qm values generally decrease as the number of accessible β-CD inclusion sites in the copolymer framework decreases. The chemical structure of the adsorbates played an important role in their relative uptake, as evidenced by the adsorbate lipophilic surface area (LSA) and the involvement of hydrophobic effects. The copolymers exhibit molecular selective sorption of the single-component carboxylates in mixtures which suggests their application as sorbents for fractionation of mixtures of NAs. By comparison, granular activated carbon (GAC) and chitosan sorbents did not exhibit any significant molecular selective sorption relative to the copolymer materials; however, evidence of variable sorption capacity was observed among the sorbents investigated.

Luminescent hybrid lanthanide sulfates and lanthanide sulfonate-carboxylates with 1,10-phenanthroline involving in-situ oxidation of 2-mercaptonbenzoic acid

NASA Astrophysics Data System (ADS)

Zhong, Jie-Cen; Wan, Fang; Sun, Yan-Qiong; Chen, Yi-Ping

2015-01-01

A series of lanthanide sulfates and lanthanide sulfonate-carboxylates, [Ln2(phen)2(SO4)3(H2O)2]n (I:Ln=Nd(1a), Sm(1b), Eu(1c), phen=1,10-phenanthroline) and [Ln(phen)(2-SBA)(BZA)]n (II: Ln=Sm(2a), Eu(2b), Dy(2c), 2-SBA=2-sulfobenzoate, BZA=benzoate) have been hydrothermally synthesized from lanthanide oxide, 2-mercaptonbenzoic acid with phen as auxiliary ligand and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra, TG analyses and luminescence spectroscopy. Interestingly, SO4 2 - anions in I came from the in situ deep oxidation of thiol groups of 2-mercaptonbenzoic acid while 2-sulfobenzoate and benzoate ligands in II from the middle oxidation and desulfuration reactions of 2-mercaptonbenzoic acid. Compounds I are organic-inorganic hybrid lanthanide sulfates, which have rare one-dimensional column-like structures. Complexes II are binuclear lanthanide sulfonate-carboxylates with 2-sulfobenzoate and benzoate as bridges and 1,10-phenanthroline as terminal. Photoluminescence studies reveal that complexes I and II exhibit strong lanthanide characteristic emission bands in the solid state at room temperature.

Porous structure and surface chemistry of phosphoric acid activated carbon from corncob

NASA Astrophysics Data System (ADS)

Sych, N. V.; Trofymenko, S. I.; Poddubnaya, O. I.; Tsyba, M. M.; Sapsay, V. I.; Klymchuk, D. O.; Puziy, A. M.

2012-11-01

Active carbons have been prepared from corncob using chemical activation with phosphoric acid at 400 °C using varied ratio of impregnation (RI). Porous structure of carbons was characterized by nitrogen adsorption and scanning electron microscopy. Surface chemistry was studied by IR and potentiometric titration method. It has been shown that porosity development was peaked at RI = 1.0 (SBET = 2081 m2/g, Vtot = 1.1 cm3/g), while maximum amount of acid surface groups was observed at RI = 1.25. Acid surface groups of phosphoric acid activated carbons from corncob includes phosphate and strongly acidic carboxylic (pK = 2.0-2.6), weakly acidic carboxylic (pK = 4.7-5.0), enol/lactone (pK = 6.7-7.4; 8.8-9.4) and phenol (pK = 10.1-10.7). Corncob derived carbons showed high adsorption capacity to copper, especially at low pH. Maximum adsorption of methylene blue and iodine was observed for carbon with most developed porosity (RI = 1.0).

2,3-Diamino-pyridinium sorbate-sorbic acid (1/1).

PubMed

Hemamalini, Madhukar; Goh, Jia Hao; Fun, Hoong-Kun

2012-01-01

In the title mol-ecular salt-adduct, C(5)H(8)N(3) (+)·C(6)H(7)O(2) (-)·C(6)H(8)O(2), the 2,3-diamino-pyridinium cation is essentially planar, with a maximum deviation of 0.013 (2) Å, and is protanated at its pyridine N atom. The sorbate anion and sorbic acid mol-ecules exist in extended conformations. In the crystal, the protonated N atom and one of the two amino-group H atoms are hydrogen bonded to the sorbate anion through a pair of N-H⋯O hydrogen bonds, forming an R(1) (2)(6) ring motif. The carboxyl groups of the sorbic acid mol-ecules and the carboxyl-ate groups of the sorbate anions are connected via O-H⋯O hydrogen bonds. Furthermore, the ion pairs and neutral mol-ecules are connected via inter-molecular N-H⋯O hydrogen bonds, forming sheets lying parallel to (100).

Saccharomyces cerevisiae sigma 1278b has novel genes of the N-acetyltransferase gene superfamily required for L-proline analogue resistance.

PubMed

Takagi, H; Shichiri, M; Takemura, M; Mohri, M; Nakamori, S

2000-08-01

We discovered on the chromosome of Saccharomyces cerevisiae Sigma 1278b novel genes involved in L-proline analogue L-azetidine-2-carboxylic acid resistance which are not present in the standard laboratory strains. The 5.4 kb-DNA fragment was cloned from the genomic library of the L-azetidine-2-carboxylic acid-resistant mutant derived from a cross between S. cerevisiae strains S288C and Sigma 1278b. The nucleotide sequence of a 4.5-kb segment exhibited no identity with the sequence in the genome project involving strain S288C. Deletion analysis indicated that one open reading frame encoding a predicted protein of 229 amino acids is indispensable for L-azetidine-2-carboxylic acid resistance. The protein sequence was found to be a member of the N-acetyltransferase superfamily. Genomic Southern analysis and gene disruption showed that two copies of the novel gene with one amino acid change at position 85 required for L-azetidine-2-carboxylic acid resistance were present on chromosomes X and XIV of Sigma 1278b background strains. When this novel MPR1 or MPR2 gene (sigma 1278b gene for L-proline analogue resistance) was introduced into the other S. cerevisiae strains, all of the recombinants were resistant to L-azetidine-2-carboxylic acid, indicating that both MPR1 and MPR2 are expressed and have a global function in S. cerevisiae.

The relationship of thioredoxin-1 and cisplatin resistance: its impact on ROS and oxidative metabolism in lung cancer cells.

PubMed

Wangpaichitr, Medhi; Sullivan, Elizabeth J; Theodoropoulos, George; Wu, Chunjing; You, Min; Feun, Lynn G; Lampidis, Theodore J; Kuo, Macus T; Savaraj, Niramol

2012-03-01

Elimination of cisplatin-resistant lung cancer cells remains a major obstacle. We have shown that cisplatin-resistant tumors have higher reactive oxygen species (ROS) levels and can be exploited for targeted therapy. Here, we show that increased secretion of the antioxidant thioredoxin-1 (TRX1) resulted in lowered intracellular TRX1 and contributed to higher ROS in cisplatin-resistant tumors in vivo and in vitro. By reconstituting TRX1 protein in cisplatin-resistant cells, we increased sensitivity to cisplatin but decreased sensitivity to elesclomol (ROS inducer). Conversely, decreased TRX1 protein in parental cells reduced the sensitivity to cisplatin but increased sensitivity to elesclomol. Cisplatin-resistant cells had increased endogenous oxygen consumption and mitochondrial activity but decreased lactic acid production. They also exhibited higher levels of argininosuccinate synthetase (ASS) and fumarase mRNA, which contributed to oxidative metabolism (OXMET) when compared with parental cells. Restoring intracellular TRX1 protein in cisplatin-resistant cells resulted in lowering ASS and fumarase mRNAs, which in turn sensitized them to arginine deprivation. Interestingly, cisplatin-resistant cells also had significantly higher basal levels of acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS). Overexpressing TRX1 lowered ACC and FAS proteins expressions in cisplatin-resistant cells. Chemical inhibition and short interfering RNA of ACC resulted in significant cell death in cisplatin-resistant compared with parental cells. Conversely, TRX1 overexpressed cisplatin-resistant cells resisted 5-(tetradecyloxy)-2-furoic acid (TOFA)-induced death. Collectively, lowering TRX1 expression through increased secretion leads cisplatin-resistant cells to higher ROS production and increased dependency on OXMET. These changes raise an intriguing therapeutic potential for future therapy in cisplatin-resistant lung cancer.

Strong-acid, carboxyl-group structures in fulvic acid from the Suwannee River, Georgia. 2. Major structures

USGS Publications Warehouse

Leenheer, J.A.; Wershaw, R. L.; Reddy, M.M.

1995-01-01

Polycarboxylic acid structures that account for the strong-acid characteristics (pKa1 near 2.0) were examined for fulvic acid from the Suwannee River. Studies of model compounds demonstrated that pKa values near 2.0 occur only if the ??-ether or ??-ester groups were in cyclic structures with two to three additional electronegative functional groups (carboxyl, ester, ketone, aromatic groups) at adjacent positions on the ring. Ester linkage removal by alkaline hydrolysis and destruction of ether linkages through cleavage and reduction with hydriodic acid confirmed that the strong carboxyl acidity in fulvic acid was associated with polycarboxylic ??-ether and ??-ester structures. Studies of hypothetical structural models of fulvic acid indicated possible relation of these polycarboxylic structures with the amphiphilic and metal-binding properties of fulvic acid.

Development of a GC/MS method for the qualitative and quantitative analysis of mixtures of free fatty acids and metal soaps in paint samples.

PubMed

La Nasa, Jacopo; Modugno, Francesca; Aloisi, Matteo; Lluveras-Tenorio, Anna; Bonaduce, Ilaria

2018-02-25

In this paper we present a new analytical GC/MS method for the analysis of mixtures of free fatty acids and metal soaps in paint samples. This approach is based on the use of two different silylating agents: N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and 1,1,1,3,3,3-hexamethyldisilazane (HMDS). Our experimentation demonstrated that HMDS does not silylate fatty acid carboxylates, so it can be used for the selective derivatization and GC/MS quantitative analysis of free fatty acids. On the other hand BSTFA is able to silylate both free fatty acids and fatty acids carboxylates. The reaction conditions for the derivatization of carboxylates with BSTFA were thus optimized with a full factorial 3 2 experimental design using lead stearate and lead palmitate as model systems. The analytical method was validated following the ICH guidelines. The method allows the qualitative and quantitative analysis of fatty acid carboxylates of sodium, calcium, magnesium, aluminium, manganese, cobalt, copper, zinc, cadmium, and lead and of lead azelate. In order to exploit the performances of the new analytical method, samples collected from two reference paint layers, from a gilded 16th century marble sculpture, and from a paint tube belonging to the atelier of Edvard Munch, used in the last period of his life (1916-1944), were characterized. Copyright © 2017 Elsevier B.V. All rights reserved.

Steroid catechol degradation: disecoandrostane intermediates accumulated by Pseudomonas transposon mutant strains.

PubMed

Leppik, R A

1989-07-01

Eleven transposon mutant strains affected in bile acid catabolism were each found to form yellow, muconic-like intermediates from bile acids. To characterize these unstable intermediates, media from the growth of one of these mutants with deoxycholic acid was treated with ammonia, then the crude product was methylated with diazomethane. Four compounds were subsequently isolated; spectral evidence suggested that they were methyl 12 alpha-hydroxy-3-oxo-23,24-dinorchola-1,4-dien-22-oate, methyl 4-aza-12 beta-hydroxy-9(10)-secoandrosta-1,3,5-triene-9,17-dione-3-carboxyl ate, 4-aza-9 alpha, 12 beta-dihydroxy-9(10)-secoandrosta-1,3,5-trien-17-one-3- methyl carboxylate and 4 alpha-[3'-propionic acid]-5-amino-7 beta-hydroxy-7 alpha beta-methyl- 3a alpha, 4,7,7a-tetrahydro-1-indanone-delta-lactam. It is proposed that the mutants are blocked in the utilization of such muconic-like compounds as the 3,12 beta-dihydroxy-5,9,17-trioxo-4(5),9(10)- disecoandrostal (10),2-dien-4-oic acid formed from deoxycholic acid. A further mutant was examined, which converted deoxycholic acid to 12 alpha-hydroxyandrosta-1,4-dien-3,17-dione, but accumulated yellow products from steroids which lacked a 12 alpha-hydroxy function, such as chenodeoxycholic acid. The products from the latter acid were treated as above; spectral evidence suggested that the two compounds isolated were methyl 4-aza-7-hydroxy-9(10)-secoandrosta-1,3,5- triene-9,17-dione-3-carboxylate and 4 alpha-[1'alpha-hydroxy-3'-propionic acid]-5-amino-7a beta-methyl-3a alpha,4,7,7a-tetrahydro-1-indanone-delta-lactam.

Synthesis, characterization and crystal structure of (2RS,4R)-2-(2-hydroxy-3-methoxyphenyl)thiazolidine-4-carboxylic acid

NASA Astrophysics Data System (ADS)

Muche, Simon; Müller, Matthias; Hołyńska, Małgorzata

2018-03-01

The condensation reaction of ortho-vanillin and L-cysteine leads to formation of a racemic mixture of (2RS,4R)-2-(2-hydroxy-3-methoxyphenyl)thiazolidine-4-carboxylic acid and not, as reported in the available literature, to a Schiff base. The racemic mixture was fully characterized by 1D and 2D NMR techniques, ESI-MS and X-ray diffraction. Addition of ZnCl2 led to formation of crystals in form of colorless needles, suitable for X-ray diffraction studies. The measured crystals were identified as the diastereomer (2R,4R)-2-(2-hydroxy-3-methoxyphenyl)thiazolidine-4-carboxylic acid 1. The bulk material is racemic. Thiazolidine exists as zwitterion in solid state, as indicated by the crystal structure.

Method for the determination of carboxylic acids in industrial effluents using dispersive liquid-liquid microextraction with injection port derivatization gas chromatography-mass spectrometry.

PubMed

Makoś, Patrycja; Fernandes, Andre; Boczkaj, Grzegorz

2017-09-29

The paper presents a new method for the determination of 15 carboxylic acids in samples of postoxidative effluents from the production of petroleum bitumens using ion-pair dispersive liquid-liquid microextraction and gas chromatography coupled to mass spectrometry with injection port derivatization. Several parameters related to the extraction and derivatization efficiency were optimized. Under optimized experimental conditions, the obtained limit of detection and quantification ranged from 0.0069 to 1.12μg/mL and 0.014 to 2.24μg/mL, respectively. The precision (RSD ranged 1.29-6.42%) and recovery (69.43-125.79%) were satisfactory. Nine carboxylic acids at concentrations ranging from 0.10μg/mL to 15.06μg/mL were determined in the raw wastewater and in samples of effluents treated by various oxidation methods. The studies revealed a substantial increase of concentration of benzoic acids, in samples of wastewater after treatment, which confirms the need of carboxylic acids monitoring during industrial effluent treatment processes. Copyright © 2017 Elsevier B.V. All rights reserved.

Amino acid analogs for tumor imaging

DOEpatents

Goodman, M.M.; Shoup, T.

1998-09-15

The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is [{sup 18}F]-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an {alpha}-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of {alpha}-aminoisobutyric acid.

Amino acid analogs for tumor imaging

DOEpatents

Goodman, M.M.; Shoup, T.

1998-10-06

The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is [{sup 18}F]-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an {alpha}-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of {alpha}-aminoisobutyric acid.

Amino acid analogs for tumor imaging

DOEpatents

Goodman, Mark M.; Shoup, Timothy

1998-09-15

The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is ›.sup.18 F!-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an .alpha.-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of .alpha.-aminoisobutyric acid.

Amino acid analogs for tumor imaging

DOEpatents

Goodman, Mark M.; Shoup, Timothy

1998-10-06

The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is ›.sup.18 F!-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an .alpha.-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of .alpha.-aminoisobutyric acid.

IR, FT-ICR-MS studies on (1'S, 6'S)-1-cyclopropyl-7-(2,8-diazabicyclo[4.3.0] non-8-yl)-6-fluoro-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid hydrochloride salt.

PubMed

Lin, Zhiwei

2014-01-01

The infrared spectra of (1'S, 6'S)-1-cyclopropyl-7-(2,8-diazabicyclo[4.3.0] non-8-yl)-6-fluoro-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid hydrochloride salt (CLF-HCl) were studied and compared with free base. Their fragmentation pathways were investigated using tandem mass spectrometric (MS/MS) techniques on Fourier-transform ion cyclotron resonance spectrum, and many characteristic fragment ions were found. Copyright © 2013 Elsevier B.V. All rights reserved.

Cytotoxic effects of polybasic acids, poly(alkenoic acid)s, and the monomers with various functional groups on human pulp fibroblasts.

PubMed

Kurata, Shigeaki; Morishita, Kumiko; Kawase, Toshio; Umemoto, Kozo

2011-01-01

This study evaluated the cytotoxicity of various polybasic acids, poly(alkenoic acid)s, and the monomers with various acidic functional groups such as carboxyl, phosphoryl, and sulfo group. The cell growth of fibroblasts cultivated in medium containing polybasic acids and polymers up to the concentration to 5 mmol/L was not significantly different compared with that of control without their acids. On the other hand, the cell growth fibroblasts cultivated in medium containing 1 mmol/L of the monomers with acryloyloxy and phosphoryl or carboxyl group decreased remarkably compared with that of the control and the cells were probably lifeless. Those exposed to the monomers with a ether bond and a carboxyl group or a amide bond and a sulfo group was not significantly different compared with that of control.

Unravelling the surface chemistry of metal oxide nanocrystals, the role of acids and bases.

PubMed

De Roo, Jonathan; Van den Broeck, Freya; De Keukeleere, Katrien; Martins, José C; Van Driessche, Isabel; Hens, Zeger

2014-07-09

We synthesized HfO2 nanocrystals from HfCl4 using a surfactant-free solvothermal process in benzyl alcohol and found that the resulting nanocrystals could be transferred to nonpolar media using a mixture of carboxylic acids and amines. Using solution (1)H NMR, FTIR, and elemental analysis, we studied the details of the transfer reaction and the surface chemistry of the resulting sterically stabilized nanocrystals. As-synthesized nanocrystals are charge-stabilized by protons, with chloride acting as the counterion. Treatment with only carboxylic acids does not lead to any binding of ligands to the HfO2 surface. On the other hand, we find that the addition of amines provides the basic environment in which carboxylic acids can dissociate and replace chloride. This results in stable, aggregate-free dispersions of HfO2 nanocrystals, sterically stabilized by carboxylate ligands. Moreover, titrations with deuterated carboxylic acid show that the charge on the carboxylate ligands is balanced by coadsorbed protons. Hence, opposite from the X-type/nonstoichiometric nanocrystals picture prevailing in literature, one should look at HfO2/carboxylate nanocrystals as systems where carboxylic acids are dissociatively adsorbed to bind to the nanocrystals. Similar results were obtained with ZrO2 NCs. Since proton accommodation on the surface is most likely due to the high Brønsted basicity of oxygen, our model could be a more general picture for the surface chemistry of metal oxide nanocrystals with important consequences on the chemistry of ligand exchange reactions.

Bacterial Transformations of Naphthothiophenes

PubMed Central

Kropp, K. G.; Andersson, J. T.; Fedorak, P. M.

1997-01-01

Naphthothiophenes are minor components of fossil fuels, and they can enter the environment from oil spills. Naphtho[2,1-b]thiophene, naphtho[2,3-b]thiophene, and 1-methylnaphtho[2,1-b]thiophene were synthesized and used in biodegradation studies with 1-methylnaphthalene (1-MN)-degrading Pseudomonas strains W1, F, and BT1. Cultures were incubated with one of the naphthothiophenes with or without 1-MN, acidified, and extracted with CH(inf2)Cl(inf2). The extracts were analyzed by gas chromatography with flame photometric and mass detectors to characterize sulfur-containing metabolites and with an atomic emission detector for quantification. Only strain W1 was able to grow on naphtho[2,1-b]thiophene, but strains F and BT1 cometabolized this compound if 1-MN was present. 1-MN was required by all three strains to metabolize naphtho[2,3-b]thiophene, which was more resistant to biodegradation than the [2,1-b] isomer. Two metabolites of naphtho [2,1-b]thiophene were purified, analyzed by (sup1)H nuclear magnetic resonance spectroscopy, and found to be 4-hydroxybenzothiophene-5-carboxylic acid (metabolite I) and 5-hydroxybenzothiophene-4-carboxylic acid (metabolite II). In cultures of strain W1 grown for 7 days on 52 (mu)mol of naphtho[2,1-b]thiophene, >84% of the substrate was degraded and metabolites I and II accounted for 19 and 9%, respectively, of the original amount of naphtho[2,1-b]thiophene. When 1-MN was present, strain W1 degraded >97% of the naphtho[2,1-b]thiophene and similar amounts of metabolite II were produced, but metabolite I did not accumulate. 1-MN was shown to promote the further degradation of metabolite I, but not of metabolite II, by strain W1. Thus, 1-MN enhanced the biodegradation of naphtho[2,1-b]thiophene. Approximately 70% of the 1-methylnaphtho [2,1-b]thiophene added to cultures of strain W1 with 1-MN was recovered as 4-hydroxy-3-methylbenzothiophene-5-carboxylic acid, the 3-methyl analog of metabolite I. The methyl substitution hindered further metabolism of 3-methyl-metabolite I even in the presence of 1-MN. Cometabolism of naphtho[2,3-b]thiophene yielded two products that were tentatively identified as 5-hydroxybenzothiophene-6-carboxylic and 6-hydroxybenzothiophene-5-carboxylic acids. PMID:16535687

40 CFR 180.479 - Halosulfuron-methyl; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... residues of the herbicide halosulfuron-methyl, methyl 3-chloro-5-[[[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl] amino] sulfonyl]-1-methyl-1H-pyrazole-4-carboxylate, and its metabolites and degradates in or on...-sulfamoylpyrazole-4-carboxylic acid, expressed as the stoichiometric equivalent of halosulfuron-methyl, in or on the...

A new irreversible enzyme-aided esterification method in organic solvents.

PubMed

Jeromin, Günter E; Zoor, Annegreth

2008-05-01

A new irreversible esterification method for carboxylic acids catalyzed by a lipase from Candida antarctica (Novozyme 435) in organic solvents has been developed. The water produced during the process is chemically destroyed by a corresponding ester of acetoacetate, which acts as a sacrificial substrate in this reaction. The flavour esters isobutyl acetate, methyl butyrate, ethyl butyrate and benzyl butyrate were synthesized either in small scale (0.05 mol) or large scale (1 mol). The yields range from 82 to 92% within 24 h at 52 degrees C. Optimal molar ratios of reactants were 1:1:1 (carboxylic acid:alcohol:acetoacetate).

Cations in component reactions of `malic' enzyme catalysis

PubMed Central

Tsai, C. S.; Tsai, Y. H.; Samad, R. A.

1971-01-01

The `malic' enzyme (EC 1.1.1.40) has been purified (300-fold) from wheat germ and its abilities to catalyse the decarboxylation and the hydrogenation of oxaloacetic acid and oxaloacetate esters was studied. The free 1-carboxyl group is essential for the interaction of oxaloacetates and substituted oxaloacetates with the enzyme via cations. The free 4-carboxyl group is required for the decarboxylation but is not indispensable for the hydrogenation. At high concentrations, cations inhibit the enzymic hydrogenation of oxaloacetic acid but not that of 4-ethyl oxaloacetate. A plausible inhibitory mechanism is proposed. PMID:4399519

Application of 1-aminocyclohexane carboxylic acid to protein nanostructure computer design

PubMed Central

Rodríguez-Ropero, Francisco; Zanuy, David; Casanovas, Jordi; Nussinov, Ruth; Alemán, Carlos

2009-01-01

Conformationally restricted amino acids are promising candidates to serve as basic pieces in redesigned protein motifs which constitute the basic modules in synthetic nanoconstructs. Here we study the ability of constrained cyclic amino acid 1-aminocyclohexane-1-carboxylic acid (Ac6c) to stabilize highly regular β-helical motifs excised from naturally occurring proteins. Calculations indicate that the conformational flexibility observed in both the ring and the main chain is significantly higher than that detected for other 1-aminocycloalkane-1-carboxylic acid (Acnc, where n refers to the size of the ring) with smaller cycles. Incorporation of Ac6c into the flexible loops of β-helical motifs indicates that the stability of such excised building blocks as well as the nano-assemblies derived from them is significantly enhanced. Thus, the intrinsic Ac6c tendency to adopt folded conformations combined with the low structural strain of the cyclohexane ring confers the ability to both self-adapt to the β-helix motif and to stabilize the overall structure by absorbing part of its conformational fluctuations. Comparison with other Acnc residues indicates that the ability to adapt to the targeted position improves considerably with the ring size, i.e. when the rigidity introduced by the strain of the ring decreases. PMID:18201062

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Ling; Zhong, Jie-Cen; Qiu, Xing-Tai

Two series of lanthanide-carboxylates, [Ln(2,2′-dtba)(2,2′-Hdtba)(EtOH)]{sub n} (I:Ln=Eu(1a), Dy(1b)) and [Ln(2,2′-dtba)(2,2′-Hdtba)(4,4′-bpy){sub 0.5}]{sub n} (II:Ln=Eu(2a), Dy(2b), Tb(2c) 2,2′-H{sub 2}dtba=2,2′-dithiodibenzoic acid, 4,4′-bpy=4,4′-bipyridine) have been synthesized under hydrothermal conditions. Interestingly, the H{sub 2}dtba organic ligand was generated by in situ S–S reaction of 2-mercaptobenzoic acid. Compounds I and II possess different 2D layered structures based on similar 1D [Ln(2,2′-dtba)]{sup +} chains. Photoluminescence studies reveal that compounds I and II exhibit strong lanthanide characteristic emission bands. Remarkably, Compounds 1b and 2a both exhibit good photocatalytic activity for degradation of Rhodamine-B (Rh-B) under the simulated sunlight irradiation. - Graphical abstract: Two series of lanthanide-carboxylates have beenmore » in situ synthesized under hydrothermal conditions. The lanthanide-carboxylates exhibit strong lanthanide characteristic emission bands and good photocatalytic activity for degradation of Rhodamine-B. - Highlights: • 2D layered lanthanide-carboxylates with 2,2′-dithiodibenzoic acid. • In situ S–S reaction of 2-mercaptobenzoic acid under hydrothermal condition. • The Emission spectra of I and II exhibit the characteristic transition of lanthanide ions. • Compounds 1b and 2a exhibit good photocatalytic activity for degradation of Rhodamine-B.« less

Two Dimensional Polyamides Prepared From Unsaturated Carboxylic Acids And Amines.

DOEpatents

McDonald, William F.; Huang, Zhi Heng; Wright, Stacy C.; Danzig, Morris; Taylor, Andrew C.

2002-07-17

A polyamide and a process for preparing the polyamide are disclosed. The process comprises reacting in a reaction mixture a monomer selected from unsaturated carboxylic acids, esters of unsaturated carboxylic acids, anhydrides of unsaturated carboxylic acids, and mixtures thereof, and a first amine to form an intermediate reaction product in the reaction mixture, wherein the first amine is selected from RR.sub.1 NH, RNH.sub.2, RR.sub.1 NH.sub.2.sup.+, RNH.sub.3.sup.+ and mixtures thereof, wherein R and R.sub.1 can be the same or different and each contain between about 1 and 50 carbon atoms and are optionally substituted with heteroatoms oxygen, nitrogen, sulfur, and phosphorus and combinations thereof, and reacting the intermediate reaction product and a second amine to form a polyamide, wherein the second amine is selected from R.sub.2 R.sub.3 NH, R.sub.2 NH.sub.2, R.sub.2 R.sub.3 NH.sub.2.sup.+, R.sub.2 NH.sub.3.sup.+ and mixtures thereof wherein R.sub.2 and R.sub.3 can be the same or different and each contain between about 1 and 50 carbon atoms and are optionally substituted with heteroatoms oxygen, nitrogen, sulfur, and phosphorus and combinations thereof, wherein multiple of the R, R.sub.1, R.sub.2, and R.sub.3 are in vertically aligned spaced relationship along a backbone formed by the polyamide. In one version of the invention, the monomer is selected from maleic anhydride, maleic acid esters, and mixtures thereof. In another version of the invention, the first amine is an alkylamine, such as tetradecylamine, and the second amine is a polyalkylene polyamine, such as pentaethylenehexamine. In yet another version of the invention, the first amine and the second amine are olefinic or acetylenic amines, such as the reaction products of an alkyldiamine and an acetylenic carboxylic acid. The first amine and the second amine may be the same or different depending on the desired polyamide polymer structure.

Synthesis and structures of cadmium carboxylate and thiocarboxylate compounds with a sulfur-rich coordination environment: Carboxylate exchange kinetics involving tris(2-mercapto-1- t-butylimidazolyl)hydroborato cadmium complexes, [Tm But]Cd(O 2CR)

DOE PAGES

Kreider-Mueller, Ava; Quinlivan, Patrick J.; Owen, Jonathan S.; ...

2015-03-31

Here, a series of cadmium carboxylate compounds in a sulfur-rich environment provided by the tris(2- tert-butylmercaptoimidazolyl)hydroborato ligand, namely, [Tm But]CdO 2CR, has been synthesized via the reactions of the cadmium methyl derivative [Tm But]CdMe with RCO 2H. Such compounds mimic aspects of cadmium-substituted zinc enzymes and also the surface atoms of cadmium chalcogenide crystals, and have therefore been employed to model relevant ligand exchange processes. Significantly, both 1H and 19F NMR spectroscopy demonstrate that the exchange of carboxylate groups between [Tm But]Cd(κ 2-O 2CR) and the carboxylic acid RCO 2H is facile on the NMR time scale, even at lowmore » temperature. Analysis of the rate of exchange as a function of concentration of RCO 2H indicates that reaction occurs via an associative rather than dissociative pathway. In addition to carboxylate compounds, the thiocarboxylate derivative [Tm But]Cd[κ 1-SC(O)Ph] has also been synthesized via the reaction of [Tm But]CdMe with thiobenzoic acid. The molecular structure of [Tm But]Cd[κ 1-SC(O)Ph] has been determined by X-ray diffraction, and an interesting feature is that, in contrast to the carboxylate derivatives [Tm But]Cd(κ 2-O 2CR), the thiocarboxylate ligand binds in a κ 1 manner via only the sulfur atom.« less

Synthesis and structures of cadmium carboxylate and thiocarboxylate compounds with a sulfur-rich coordination environment: Carboxylate exchange kinetics involving tris(2-mercapto-1- t-butylimidazolyl)hydroborato cadmium complexes, [Tm But]Cd(O 2CR)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kreider-Mueller, Ava; Quinlivan, Patrick J.; Owen, Jonathan S.

Here, a series of cadmium carboxylate compounds in a sulfur-rich environment provided by the tris(2- tert-butylmercaptoimidazolyl)hydroborato ligand, namely, [Tm But]CdO 2CR, has been synthesized via the reactions of the cadmium methyl derivative [Tm But]CdMe with RCO 2H. Such compounds mimic aspects of cadmium-substituted zinc enzymes and also the surface atoms of cadmium chalcogenide crystals, and have therefore been employed to model relevant ligand exchange processes. Significantly, both 1H and 19F NMR spectroscopy demonstrate that the exchange of carboxylate groups between [Tm But]Cd(κ 2-O 2CR) and the carboxylic acid RCO 2H is facile on the NMR time scale, even at lowmore » temperature. Analysis of the rate of exchange as a function of concentration of RCO 2H indicates that reaction occurs via an associative rather than dissociative pathway. In addition to carboxylate compounds, the thiocarboxylate derivative [Tm But]Cd[κ 1-SC(O)Ph] has also been synthesized via the reaction of [Tm But]CdMe with thiobenzoic acid. The molecular structure of [Tm But]Cd[κ 1-SC(O)Ph] has been determined by X-ray diffraction, and an interesting feature is that, in contrast to the carboxylate derivatives [Tm But]Cd(κ 2-O 2CR), the thiocarboxylate ligand binds in a κ 1 manner via only the sulfur atom.« less

Validation of a method for quantitation of the clopidogrel active metabolite, clopidogrel, clopidogrel carboxylic acid, and 2-oxo-clopidogrel in feline plasma.

PubMed

Lyngby, Janne G; Court, Michael H; Lee, Pamela M

2017-08-01

The clopidogrel active metabolite (CAM) is unstable and challenging to quantitate. The objective was to validate a new method for stabilization and quantitation of CAM, clopidogrel, and the inactive metabolites clopidogrel carboxylic acid and 2-oxo-clopiodgrel in feline plasma. Two healthy cats administered clopidogrel to demonstrate assay in vivo utility. Stabilization of CAM was achieved by adding 2-bromo-3'methoxyacetophenone to blood tubes to form a derivatized CAM (CAM-D). Method validation included evaluation of calibration curve linearity, accuracy, and precision; within and between assay precision and accuracy; and compound stability using spiked blank feline plasma. Analytes were measured by high performance liquid chromatography with tandem mass spectrometry. In vivo utility was demonstrated by a pharmacokinetic study of cats given a single oral dose of 18.75mg clopidogrel. The 2-oxo-clopidogrel metabolite was unstable. Clopidogrel, CAM-D, and clopidogrel carboxylic acid appear stable for 1 week at room temperature and 9 months at -80°C. Standard curves showed linearity for CAM-D, clopidogrel, and clopidogrel carboxylic acid (r > 0.99). Between assay accuracy and precision was ≤2.6% and ≤7.1% for CAM-D and ≤17.9% and ≤11.3% for clopidogrel and clopidogrel carboxylic acid. Within assay precision for all three compounds was ≤7%. All three compounds were detected in plasma from healthy cats receiving clopidogrel. This methodology is accurate and precise for simultaneous quantitation of CAM-D, clopidogrel, and clopidogrel carboxylic acid in feline plasma but not 2-oxo-clopidogrel. Validation of this assay is the first step to more fully understanding the use of clopidogrel in cats. Copyright © 2017 Elsevier B.V. All rights reserved.

Selenium carboxylic acids betaine; 3,3‧,3″-selenotris(propanoic acid) betaine, Se(CH2CH2COOH)2(CH2CH2COO)

NASA Astrophysics Data System (ADS)

Doudin, Khalid; Törnroos, Karl W.

2017-06-01

Attempts to prepare [Se(CH2CH2COOH)3]+Cl- from Se(CH2CH2COOH)2 and H2Cdbnd CHCOOH in concentrated hydrochloric acid, for the corresponding sulfonium salt, led exclusively to the Se-betaine, Se(CH2CH2COOH)2(CH2CH2COO). The Se-betaine crystallises in the space group P2l/c with the cell dimensions at 223 K, a = 5.5717(1), b = 24.6358(4), c = 8.4361(1) Å, β = 104.762(1)°, V = 1119.74(3) Å3, Z = 4, Dcalc = 1.763 Mgm- 3, μ = 3.364 Mm-1. The structure refined to RI = 0.0223 for 2801 reflections with Fo > 4σ(Fo). In the crystalline state the molecule is intermolecularly linked to neighbouring molecules by a number of hydrogen bonds; a very strong carboxylic-carboxylate bond with an O⋯O distance of 2.4435(16) Å, a medium strong carboxylic-carboxylate bond with an O⋯O distance of 2.6431(16) Å and several weak O⋯H(CH2) with O⋯C distances between 3.2 and 3.3 Å. In the carboxylic group involved in the very strong hydrogen bond the O⋯H bond is antiperiplanar to the Cdbnd O bond while the Osbnd H bond is periplanar to the Cdbnd O bond in the second carboxylic group. Based upon the Csbnd O bond lengths and the elongation of the Osbnd H bond involved in the strong hydrogen bond one may describe the compound as strongly linked units of Se(CH2CH2COOH)(CH2CH2COO)2 rather than Se(CH2CH2COOH)2(CH2CH2COO). The selenium atom forms two strong intramolecular 1,5-Se⋯O contacts, with a carboxylate oxygen atom, 2.9385(12) Å, and with a carboxylic oxygen atom, 2.8979(11) Å. To allow for these contacts the two organic fragments have been forced into the periplanar conformation. The molecule is only slightly asymmetric with regard to the Csbnd Sesbnd C bond angles but is very asymmetric with regard to the torsion angles.

Microbial Transformation of Esters of Chlorinated Carboxylic Acids

PubMed Central

Paris, D. F.; Wolfe, N. L.; Steen, W. C.

1984-01-01

Two groups of compounds were selected for microbial transformation studies. In the first group were carboxylic acid esters having a fixed aromatic moiety and an increasing length of the alkyl component. Ethyl esters of chlorine-substituted carboxylic acids were in the second group. Microorganisms from environmental waters and a pure culture of Pseudomonas putida U were used. The bacterial populations were monitored by plate counts, and disappearance of the parent compound was followed by gas-liquid chromatography as a function of time. The products of microbial hydrolysis were the respective carboxylic acids. Octanol-water partition coefficients (Kow) for the compounds were measured. These values spanned three orders of magnitude, whereas microbial transformation rate constants (kb) varied only 50-fold. The microbial rate constants of the carboxylic acid esters with a fixed aromatic moiety increased with an increasing length of alkyl substituents. The regression coefficient for the linear relationships between log kb and log Kow was high for group 1 compounds, indicating that these parameters correlated well. The regression coefficient for the linear relationships for group 2 compounds, however, was low, indicating that these parameters correlated poorly. PMID:16346459

Transcriptomic events associated with internal browning of apple during postharvest storage.

PubMed

Mellidou, Ifigeneia; Buts, Kim; Hatoum, Darwish; Ho, Quang Tri; Johnston, Jason W; Watkins, Christopher B; Schaffer, Robert J; Gapper, Nigel E; Giovannoni, Jim J; Rudell, David R; Hertog, Maarten L A T M; Nicolai, Bart M

2014-11-28

Postharvest ripening of apple (Malus x domestica) can be slowed down by low temperatures, and a combination of low O2 and high CO2 levels. While this maintains the quality of most fruit, occasionally storage disorders such as flesh browning can occur. This study aimed to explore changes in the apple transcriptome associated with a flesh browning disorder related to controlled atmosphere storage using RNA-sequencing techniques. Samples from a browning-susceptible cultivar ('Braeburn') were stored for four months under controlled atmosphere. Based on a visual browning index, the inner and outer cortex of the stored apples was classified as healthy or affected tissue. Over 600 million short single-end reads were mapped onto the Malus consensus coding sequence set, and differences in the expression profiles between healthy and affected tissues were assessed to identify candidate genes associated with internal browning in a tissue-specific manner. Genes involved in lipid metabolism, secondary metabolism, and cell wall modifications were highly modified in the affected inner cortex, while energy-related and stress-related genes were mostly altered in the outer cortex. The expression levels of several of them were confirmed using qRT-PCR. Additionally, a set of novel browning-specific differentially expressed genes, including pyruvate dehydrogenase and 1-aminocyclopropane-1-carboxylate oxidase, was validated in apples stored for various periods at different controlled atmosphere conditions, giving rise to potential biomarkers associated with high risk of browning development. The gene expression data presented in this study will help elucidate the molecular mechanism of browning development in apples at controlled atmosphere storage. A conceptual model, including energy-related (linked to the tricarboxylic acid cycle and the electron transport chain) and lipid-related genes (related to membrane alterations, and fatty acid oxidation), for browning development in apple is proposed, which may be relevant for future studies towards improving the postharvest life of apple.

A Precise Method for Processing Data to Determine the Dissociation Constants of Polyhydroxy Carboxylic Acids via Potentiometric Titration.

PubMed

Huang, Kaixuan; Xu, Yong; Lu, Wen; Yu, Shiyuan

2017-12-01

The thermodynamic dissociation constants of xylonic acid and gluconic acid were studied via potentiometric methods, and the results were verified using lactic acid, which has a known pKa value, as a model compound. Solutions of xylonic acid and gluconic acid were titrated with a standard solution of sodium hydroxide. The determined pKa data were processed via the method of derivative plots using computer software, and the accuracy was validated using the Gran method. The dissociation constants associated with the carboxylic acid group of xylonic and gluconic acids were determined to be pKa 1  = 3.56 ± 0.07 and pKa 1  = 3.74 ± 0.06, respectively. Further, the experimental data showed that the second deprotonation constants associated with a hydroxyl group of each of the two acids were pKa 2  = 8.58 ± 0.12 and pKa 2  = 7.06 ± 0.08, respectively. The deprotonation behavior of polyhydroxy carboxylic acids was altered using various ratios with Cu(II) to form complexes in solution, and this led to proposing a hypothesis for further study.

Synthesis of Side Chain Liquid Crystal Polymers by Living Ring Opening Metathesis Polymerization. 3. Influence of Molecular Weight, Interconnecting Unit and Substituent on the Mesomorphic behavior of Polymers with Laterally Attached Mesogens

DTIC Science & Technology

1992-04-08

polymethylsiloxanes, 6 -7 polyacrylates ,2,4,5 polymethacrylates, 1 ,3 and polychloroacrylates, 5 exhibit only nematic mesophases regardless of the...corresponding carboxyl chloride. Potassium bicyclo[2.2.1]hept-2-ene-5- carboxylate was prepared by titrating a methanolic solution of the carboxylic acid...Esterification of the Corresponding Benzyl Bromides. Monomers 1I-n were prepared in 47-88% yield using the following procedure. A mixture of potassium bicyclo

Effect of alkali metal ions on the pyrrole and pyridine π-electron systems in pyrrole-2-carboxylate and pyridine-2-carboxylate molecules: FT-IR, FT-Raman, NMR and theoretical studies

NASA Astrophysics Data System (ADS)

Świderski, G.; Wojtulewski, S.; Kalinowska, M.; Świsłocka, R.; Lewandowski, W.

2011-05-01

The FT-IR, FT-Raman and 1H and 13C NMR spectra of pyrrole-2-carboxylic acid (PCA) and lithium, sodium, potassium, rubidium and caesium pyrrole-2-carboxylates were recorded, assigned and compared in the Li → Na → K → Rb → Cs salt series. The effect of alkali metal ions on the electronic system of ligands was discussed. The obtained results were compared with previously reported ones for pyridine-2-carboxylic acid and alkali metal pyridine-2-carboxylates. Calculations for pyrrole-2-carboxylic acid and Li, Na, K pyrrole-2-carboxylates in B3LYP/6-311++G ** level and Møller-Plesset method in MP2/6-311++G ** level were made. Bond lengths, angles and dipole moments as well as aromaticity indices (HOMA, EN, GEO, I 6) for the optimized structures of pyrrole-2-carboxylic acid (PCA) and lithium, sodium, potassium pyrrole-2-carboxylates were also calculated. The degree of perturbation of the aromatic system of ligand under the influence of metals in the Li → Cs series was investigated with the use of statistical methods (linear correlation), calculated aromaticity indices and Mulliken, NBO and ChelpG population analysis method. Additionally, the Bader theory (AIM) was applied to setting the characteristic of the bond critical points what confirmed the influence of alkali metals on the pyrrole ring.

Are carboxyl groups the most acidic sites in amino acids? Gas-phase acidities, photoelectron spectra, and computations on tyrosine, p-hydroxybenzoic acid, and their conjugate bases.

PubMed

Tian, Zhixin; Wang, Xue-Bin; Wang, Lai-Sheng; Kass, Steven R

2009-01-28

Deprotonation of tyrosine in the gas phase was found to occur preferentially at the phenolic site, and the conjugate base consists of a 70:30 mixture of phenoxide and carboxylate anions at equilibrium. This result was established by developing a chemical probe for differentiating these two isomers, and the presence of both ions was confirmed by photoelectron spectroscopy. Equilibrium acidity measurements on tyrosine indicated that deltaG(acid)(o) = 332.5 +/- 1.5 kcal mol(-1) and deltaH(acid)(o) = 340.7 +/- 1.5 kcal mol(-1). Photoelectron spectra yielded adiabatic electron detachment energies of 2.70 +/- 0.05 and 3.55 +/- 0.10 eV for the phenoxide and carboxylate anions, respectively. The H/D exchange behavior of deprotonated tyrosine was examined using three different alcohols (CF3CH2OD, C6H5CH2OD, and CH3CH2OD), and incorporation of up to three deuterium atoms was observed. Two pathways are proposed to account for these results, and all of the experimental findings are supplemented with B3LYP/aug-cc-pVDZ and G3B3 calculations. In addition, it was found that electrospray ionization of tyrosine from a 3:1 (v/v) CH3OH/H2O solution using a commercial source produces a deprotonated [M-H]- anion with the gas-phase equilibrium composition rather than the structure of the ion that exists in aqueous media. Electrospray ionization from acetonitrile, however, leads largely to the liquid-phase (carboxylate) structure. A control molecule, p-hydroxybenzoic acid, was found to behave in a similar manner. Thus, the electrospray conditions that are employed for the analysis of a compound can alter the isomeric composition of the resulting anion.

Synthesis and biological evaluation of pyrazolylthiazole carboxylic acids as potent anti-inflammatory-antimicrobial agents.

PubMed

Khloya, Poonam; Kumar, Satish; Kaushik, Pawan; Surain, Parveen; Kaushik, Dhirender; Sharma, Pawan K

2015-03-15

Current Letter presents design, synthesis and biological evaluation of a novel series of pyrazolylthiazole carboxylates 1a-1p and corresponding acid derivatives 2a-2p. All 32 novel compounds were tested for their in vivo anti-inflammatory activity by carrageenan-induced rat paw edema method as well as for in vitro antimicrobial activity. All the tested compounds exhibited excellent AI activity profile. Three compounds 1p (R=Cl, R(1)=Cl), 2c (R=H, R(1)=F) and 2n (R=Cl, R(1)=OCH3) were identified as potent anti-inflammatory agents exhibiting edema inhibition of 93.06-89.59% which is comparable to the reference drug indomethacin (91.32%) after 3h of carrageenan injection while most of the other compounds displayed inhibition ⩾80%. In addition, pyrazolylthiazole carboxylic acids (2a-2p) also showed good antimicrobial profile. Compound 2h (R=OCH3, R(1)=Cl) showed excellent antimicrobial activity (MIC 6.25μg/mL) against both Gram positive bacteria comparable with the reference drug ciprofloxacin (MIC 6.25μg/mL). Copyright © 2015 Elsevier Ltd. All rights reserved.

Determination of polyfluoroalkyl phosphoric acid diesters, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, perfluoroalkyl carboxylic acids, and perfluoroalkane sulfonic acids in lake trout from the Great Lakes region.

PubMed

Guo, Rui; Reiner, Eric J; Bhavsar, Satyendra P; Helm, Paul A; Mabury, Scott A; Braekevelt, Eric; Tittlemier, Sheryl A

2012-11-01

A comprehensive method to extract perfluoroalkyl carboxylic acids, perfluoroalkane sulfonic acids, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, and polyfluoroalkyl phosphoric acid diesters simultaneously from fish samples has been developed. The recoveries of target compounds ranged from 78 % to 121 %. The new method was used to analyze lake trout (Salvelinus namaycush) from the Great Lakes region. The results showed that the total perfluoroalkane sulfonate concentrations ranged from 0.1 to 145 ng/g (wet weight) with perfluorooctane sulfonate (PFOS) as the dominant contaminant. Concentrations in fish between lakes were in the order of Lakes Ontario ≈ Erie > Huron > Superior ≈ Nipigon. The total perfluoroalkyl carboxylic acid concentrations ranged from 0.2 to 18.2 ng/g wet weight. The aggregate mean perfluorooctanoic acid (PFOA) concentration in fish across all lakes was 0.045 ± 0.023 ng/g. Mean concentrations of PFOA were not significantly different (p > 0.1) among the five lakes. Perfluoroalkyl phosphinic acids were detected in lake trout from Lake Ontario, Lake Erie, and Lake Huron with concentration ranging from non-detect (ND) to 0.032 ng/g. Polyfluoroalkyl phosphoric acid diesters were detected only in lake trout from Lake Huron, at levels similar to perfluorooctanoic acid.

Pentavalent Bismuth-Mediated Glycosylation Methods to Activate Sialic and Uronic Acids and the Incorporation of Sialic Acids Into Insulin

NASA Astrophysics Data System (ADS)

Kabotso, Daniel Elorm Kwame

The negative charge at physiological pH of carboxylic acid-containing monosaccharides modulate the properties of many natural biomolecules such as oligosaccharides and glycoconjugates. Unfortunately, these altered electronic properties also make the incorporation of such acidic sugars more challenging as compared to the more commonly studied neutral sugars. Herein are reported the first demonstration of glycosylation reactions mediated by triphenylbis(1,1,1-trifluoromethanesulfonato)-bismuth with thioglycosides containing carboxylic acid substituents protected as esters. Unlike with many neutral sugar substrates, the addition of 1-propanethiol to the reactions proved critical to obtaining good yields of the desired glycosylation products using sialic acid, galacturonic acid, and glucuronic acid. The protocol was demonstrated to be amenable to automation using a liquid-handling platform. The consequences of artificially incorporating carboxylic-acid-containing sugars into proteins were tested by the design of a linker containing 1 to 4 sialic acids--a sugar found in many human proteins and brain tissues--that was attached via reductive amination of trityl thiopropylaldehyde at the phenyl alanine terminal end of the protein insulin produced through solid-phase peptide synthesis. Removal of the trityl group with neat trifluoroacetic acid furnished the thiol-free modified insulin that was ligated via a disulfide bond to the peptide scaffold bearing acetyl protected sialic acids. A 14-15% ammonium hydroxide solution was found to be effective in deprotecting the acetyl groups without degradation of the disulfide bond. In addition to maintaining the potency and bioactivity of insulin, the sialic acid-containing linker rendered insulin more resistant to aggregation due to heat and mechanical agitation compared to the unmodified protein.

1-(2-aminophenyl)-1H-1,2,3-triazole-4-carboxylic acid: activity against Gram-positive and Gram-negative pathogens including Vibrio cholerae

NASA Astrophysics Data System (ADS)

Maji, Krishnendu; Haldar, Debasish

2017-10-01

We report a new synthetic aromatic ε-amino acid containing a triazole moiety with antimicrobial potential against Gram-positive, Gram-negative and pathogenic bacteria including Vibrio cholerae. Structure-property relationship studies revealed that all the functional groups are essential to enhance the antimicrobial activity. The 1-(2-aminophenyl)-1H-1,2,3-triazole-4-carboxylic acid was synthesized by click chemistry. From X-ray crystallography, the amino acid adopts a kink-like structure where the phenyl and triazole rings are perpendicular to each other and the amine and acid groups maintain an angle of 60°. The agar diffusion test shows that the amino acid has significant antibacterial activity. The liquid culture test exhibits that the minimum inhibitory concentration (MIC) value for Bacillus subtilis and Vibrio cholerae is 59.5 µg ml-1. FE-SEM experiments were performed to study the morphological changes of bacterial shape after treatment with compound 1. The antimicrobial activity of the amino acid was further studied by DNA binding and degradation study, protein binding, dye-binding assay and morphological analysis. Moreover, the amino acid does not have any harmful effect on eukaryotes.

8,10-Diiodo-2,6-dioxo-4λ-ioda-3,5-dioxatricyclo-[5.3.1.0]undeca-1(11),7,9-triene-9-carb-oxy-lic acid.

PubMed

Sheng, Daopeng; Han, Lu; Zhang, Yi; Yang, Yanzhao

2012-03-01

In the title compound, C(9)HI(3)O(6)·2H(2)O, the mol-ecule is located on a twofold axis that gives rise to disorder of the carboxyl group. This disorder is correlated with the disorder of one of the H atoms of the water mol-ecule. The carboxyl group is twisted relative to the attached benzene ring by 75.1 (4)°. The intra-molecular I⋯O distance is 2.112 (6) Å. Mol-ecules are linked via O-H⋯O hydrogen bonding, C-I⋯O halogen bonding, with I⋯O distances in the range 3.156 (5)-3.274 (6) Å, and dipolar C=O⋯C=O inter-actions between the carboxyl and carboxyl-ate groups, with an O⋯C distance of 2.944 (10) Å.

Infrared Spectroscopy Determination of Lead Binding to Ethylenediaminotetraacetic Acid

NASA Astrophysics Data System (ADS)

Fitch, Alanah; Dragan, Simona

1998-08-01

In an attempt to improve a thematic lab sequence based on lead analysis of community derived samples, we have considered infrared spectroscopy as a method of determining the lead bound to ethylenediaminotetraacetic acid (EDTA). Students get acquainted with infrared spectroscopy by interpreting the spectra of EDTA, disodium ethylenediaminotetraacetate (Na2EDTA) and of lead(II) ethylenediaminotetraacetate (PbEDTA). Spectral characterization of the above compounds in the 1800-1500 cm-1 region gives information about the structural changes that sodium and lead binding to EDTA, respectively, produce. The spectra show the carboxylic carbonyl absorption band shifted from 1697 cm-1 to 1633 cm-1 in Na2EDTA, and two distinctive absorption bands at 1697 cm-1 and 1558 cm-1 in PbEDTA, the former being attributed to the "free" carboxylic group, as in EDTA, and the latter to the coordinated carboxylate with the bond order of less than 1.5 between the carbon and oxygen atoms. These features led us to the conclusion that the divalent Pb is tetra-coordinated having two covalent metal-nitrogen bonds and two ionic metal-carboxylate bonds. Based on the spectral differences between PbEDTA and EDTA, we have developed a method to quantitate the amount of lead bound to EDTA by simply comparing the peak height of the most prominent peaks in the 1800-1550 cm-1 region. A potential application of this method could be determination of lead extracted by binding it to ethylenediaminotetraacetic acid, excess EDTA being added.

Studies of the chemical basis of the origin of protein synthesis Initiation and direction of peptide growth

NASA Technical Reports Server (NTRS)

Mullins, D. W., Jr.; Lacey, J. C., Jr.

1980-01-01

The data presented in this paper show that the ease of nonenzymatic activation of carboxylic acids by ATP at pH 5 varies directly with the pKa of the carboxyl group, and is consistent with the idea that it is the protonated form of the carboxyl group which participates in the activation reaction. Consequently, since most N-blocked amino acids have higher pKas than do their unblocked forms, they are activated more readily, and it has been demonstrated that this principle applies to peptides as well, which are activated more rapidly than single amino acids. It is proposed that this fact may be partly responsible for the origin of two important features still observed in contemporary protein synthesis: (1) initiation in prokaryotes is accomplished with an N-blocked amino acid, and (2) elongation in all living systems occurs at the carboxyl end of the growing peptide.

Age-related changes in anterior cingulate cortex glutamate in schizophrenia: A (1)H MRS Study at 7 Tesla.

PubMed

Brandt, Allison S; Unschuld, Paul G; Pradhan, Subechhya; Lim, Issel Anne L; Churchill, Gregory; Harris, Ashley D; Hua, Jun; Barker, Peter B; Ross, Christopher A; van Zijl, Peter C M; Edden, Richard A E; Margolis, Russell L

2016-04-01

The extent of age-related changes in glutamate and other neurometabolites in the anterior cingulate cortex (ACC) in individuals with schizophrenia remain unclear. Magnetic resonance spectroscopy (MRS) at 7 T, which yields precise measurements of various metabolites and can distinguish glutamate from glutamine, was used to determine levels of ACC glutamate and other metabolites in 24 individuals with schizophrenia and 24 matched controls. Multiple regression analysis revealed that ACC glutamate decreased with age in patients but not controls. No changes were detected in levels of glutamine, N-acetylaspartate, N-acetylaspartylglutamic acid, myo-inositol, GABA, glutathione, total creatine, and total choline. These results suggest that age may be an important modifier of ACC glutamate in schizophrenia. Copyright © 2016 Elsevier B.V. All rights reserved.

Conformational Behaviour of Azasugars Based on Mannuronic Acid.

PubMed

van Rijssel, Erwin R; Janssen, Antonius P A; Males, Alexandra; Davies, Gideon J; van der Marel, Gijsbert A; Overkleeft, Herman S; Codée, Jeroen D C

2017-07-04

A set of mannuronic-acid-based iminosugars, consisting of the C-5-carboxylic acid, methyl ester and amide analogues of 1deoxymannorjirimicin (DMJ), was synthesised and their pH-dependent conformational behaviour was studied. Under acidic conditions the methyl ester and the carboxylic acid adopted an "inverted" 1 C 4 chair conformation as opposed to the "normal" 4 C 1 chair at basic pH. This conformational change is explained in terms of the stereoelectronic effects of the ring substituents and it parallels the behaviour of the mannuronic acid ester oxocarbenium ion. Because of this solution-phase behaviour, the mannuronic acid ester azasugar was examined as an inhibitor for a Caulobacter GH47 mannosidase that hydrolyses its substrates by way of a reaction itinerary that proceeds through a 3 H 4 transition state. No binding was observed for the mannuronic acid ester azasugar, but sub-atomic resolution data were obtained for the DMJ⋅CkGH47 complex, showing two conformations- 3 S 1 and 1 C 4 -for the DMJ inhibitor. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Ferromagnetic coupling in the three-dimensional malonato-bridged gadoliniumIII complex [Gd2(mal)3(H2O)6] (H2mal = malonic acid).

PubMed

Hernández-Molina, María; Ruiz-Pérez, Catalina; López, Trinidad; Lloret, Francesc; Julve, Miguel

2003-09-08

The novel gadolinium(III) complex of formula [Gd(2)(mal)(3)(H(2)O)(6)] (1) (H(2)mal = 1,3-propanedioic acid) has been prepared and characterized by X-ray diffraction analysis. Crystal data for 1: monoclinic, space group I2/a, a = 11.1064(10) A, b = 12.2524(10) A, c =13.6098(2) A, beta = 92.925(10) degrees, U = 1849.5(3) A(3), Z = 4. Compound 1 is a three-dimensional network made up of malonate-bridged gadolinium(III) ions where the malonate exhibits two bridging modes, eta(5)-bidentate + unidentate and eta(3):eta(3) + bis(unidentate). The gadolinium atom is nine-coordinate with three water molecules and six malonate oxygen atoms from three malonate ligands forming a distorted monocapped square antiprism. The shortest metal-metal separations are 4.2763(3) A [through the oxo-carboxylate bridge] and 6.541(3) A [through the carboxylate in the anti-syn coordination mode]. The value of the angle at the oxo-carboxylate atom is 116.8(2) degrees. Variable-temperature magnetic susceptibility measurements reveal the occurrence of a significant ferromagnetic interaction through the oxo-carboxylate pathway (J = +0.048(1) cm(-1), H = -JS(Gd(1)) x S(Gd(1a))).

Supramolecular architectures in the salt trimethoprimium ferrocene-1-carboxylate and the cocrystal 4-amino-5-chloro-2,6-dimethylpyrimidine-ferrocene-1-carboxylic acid (1/1).

PubMed

Swinton Darious, Robert; Thomas Muthiah, Packianathan; Perdih, Franc

2017-09-01

In the salt trimethoprimium ferrocenecarboxylate [systematic name: 2,4-diamino-5-(3,4,5-trimethoxybenzyl)pyrimidin-1-ium ferrocene-1-carboxylate], (C 14 H 19 N 4 O 3 )[Fe(C 5 H 5 )(C 6 H 4 O 2 )], (I), of the antibacterial compound trimethoprim, the carboxylate group interacts with the protonated aminopyrimidine group of trimethoprim via two N-H...O hydrogen bonds, generating a robust R 2 2 (8) ring motif (heterosynthon). However, in the cocrystal 4-amino-5-chloro-2,6-dimethylpyrimidine-ferrocene-1-carboxylic acid (1/1), [Fe(C 5 H 5 )(C 6 H 5 O 2 )]·C 6 H 8 ClN 3 , (II), the carboxyl-aminopyrimidine interaction [R 2 2 (8) motif] is absent. The carboxyl group interacts with the pyrimidine ring via a single O-H...N hydrogen bond. The pyrimidine rings, however, form base pairs via a pair of N-H...N hydrogen bonds, generating an R 2 2 (8) supramolecular homosynthon. In salt (I), the unsubstituted cyclopentadienyl ring is disordered over two positions, with a refined site-occupation ratio of 0.573 (10):0.427 (10). In this study, the two five-membered cyclopentadienyl (Cp) rings of ferrocene are in a staggered conformation, as is evident from the C...Cg...Cg...C pseudo-torsion angles, which are in the range 36.13-37.53° for (I) and 22.58-23.46° for (II). Regarding the Cp ring of the minor component in salt (I), the geometry of the ferrocene ring is in an eclipsed conformation, as is evident from the C...Cg...Cg...C pseudo-torsion angles, which are in the range 79.26-80.94°. Both crystal structures are further stabilized by weak π-π interactions.

Process for the generation of .alpha., .beta.-unsaturated carboxylic acids and esters using niobium catalyst

DOEpatents

Gogate, Makarand Ratnakav; Spivey, James Jerome; Zoeller, Joseph Robert

1999-01-01

A process using a niobium catalyst includes the step of reacting an ester or carboxylic acid with oxygen and an alcohol in the presence a niobium catalyst to respectively produce an .alpha.,.beta.-unsaturated ester or carboxylic acid. Methanol may be used as the alcohol, and the ester or carboxylic acid may be passed over the niobium catalyst in a vapor stream containing oxygen and methanol. Alternatively, the process using a niobium catalyst may involve the step of reacting an ester and oxygen in the presence the niobium catalyst to produce an .alpha.,.beta.-unsaturated carboxylic acid. In this case the ester may be a methyl ester. In either case, niobium oxide may be used as the niobium catalyst with the niobium oxide being present on a support. The support may be an oxide selected from the group consisting of silicon oxide, aluminum oxide, titanium oxide and mixtures thereof. The catalyst may be formed by reacting niobium fluoride with the oxide serving as the support. The niobium catalyst may contain elemental niobium within the range of 1 wt % to 70 wt %, and more preferably within the range of 10 wt % to 30 wt %. The process may be operated at a temperature from 150 to 450.degree. C. and preferably from 250 to 350.degree. C. The process may be operated at a pressure from 0.1 to 15 atm. absolute and preferably from 0.5-5 atm. absolute. The flow rate of reactants may be from 10 to 10,000 L/kg.sub.(cat) /h, and preferably from 100 to 1,000 L/kg.sub.(cat) /h.

Carboxyl-terminal isoprenylation of ras-related GTP-binding proteins encoded by rac1, rac2, and ralA.

PubMed

Kinsella, B T; Erdman, R A; Maltese, W A

1991-05-25

Membrane localization of p21ras is dependent upon its posttranslational modification by a 15-carbon farnesyl group. The isoprenoid is linked to a cysteine located within a conserved carboxyl-terminal sequence termed the "CAAX" box (where C is cysteine, A is an aliphatic amino acid, and X is any amino acid). We now show that three GTP-binding proteins encoded by the recently identified rac1, rac2, and ralA genes also undergo isoprenoid modification. cDNAs coding for each protein were transcribed in vitro, and the RNAs were translated in reticulocyte lysates. Incorporation of isoprenoid precursors, [3H]mevalonate or [3H]farnesyl pyrophosphate, indicated that the translation products were modified by isoprenyl groups. A protein recognized by an antibody to rac1 also comigrated with a protein metabolically labeled by a product of [3H] mevalonate in cultured cells. Gel permeation chromatography of radiolabeled hydrocarbons released from the rac1, rac2, and ralA proteins by reaction with Raney nickel catalyst indicated that unlike p21Hras, which was modified by a 15-carbon moiety, the rac and ralA translation products were modified by 20-carbon isoprenyl groups. Site-directed mutagenesis established that the isoprenylated cysteines in the rac1, rac2, and ralA proteins were located in the fourth position from the carboxyl terminus. The three-amino acid extension distal to the cysteine was required for this modification. The isoprenylation of rac1 (CSLL), ralA (CCIL), and the site-directed mutants rac1 (CRLL) and ralA (CSIL), demonstrates that the amino acid adjacent to the cysteine need not be aliphatic. Therefore, proteins with carboxyl-terminal CXXX sequences that depart from the CAAX motif should be considered as potential targets for isoprenoid modification.

The P1 and P1' residue specificities of physarolisin I, a serine-carboxyl peptidase from the true slime mold Physarum polycephalum.

PubMed

Nishii, Wataru; Kubota, Keiko; Takahashi, Kenji

2009-05-01

The P1 and P1' residue specificities of physarolisin I were investigated using combinatorial peptide substrates. The results indicated that certain hydrophobic residues and acidic residues are preferred at the P1 position and some hydrophobic residues at the P1' position. This P1 specificity, different from other serine-carboxyl peptidases, appears to be explained partially by the nature of the S1 subsite residues.

Synthesis and anticandidal activity of some imidazopyridine derivatives.

PubMed

Kaplancikli, Zafer Asim; Turan-Zitouni, Gülhan; Ozdemir, Ahmet; Revial, Gilbert

2008-12-01

New hydrazide derivatives of imidazo[1,2-a]pyridine have been synthesized and evaluated for anticandidal activity. The reaction of imidazo[1,2-a]pyridine-2-carboxylic acid hydrazides with various benzaldehydes gave N-(benzylidene)imidazo[ 1,2-a]pyridine-2-carboxylic acid hydrazide derivatives. Their anticandidal activities against Candida albicans and Candida glabrata (isolates obtained from Osmangazi University, Faculty of Medicine, Eskisehir, Turkey), Candida albicans (ATCC 90028), Candida utilis (NRLL Y-900), Candida tropicalis (NRLL Y-12968), Candida krusei (NRLL Y-7179), Candida zeylanoides (NRLL Y-1774), and Candida parapsilosis (NRLL Y-12696) were investigated.