scholarly journals Dehydrocostus lactone, a naturally occurring polar auxin transport inhibitor, inhibits epicotyl growth by interacting with auxin in etiolated Pisum sativum seedlings

2019 ◽  
Vol 72 (3) ◽  
Author(s):  
Yuta Toda ◽  
Kazuho Okada ◽  
Junichi Ueda ◽  
Kensuke Miyamoto
Keyword(s):  
Auxin Transport ◽  
Sesquiterpene Lactones ◽  
Polar Auxin Transport ◽  
Stem Growth ◽  
Dependent Manner ◽  
Naturally Occurring ◽  
Pea Seedlings ◽  
Genes Encoding ◽  
Pea Epicotyl ◽  
Dehydrocostus Lactone

We have isolated germacranolide-type sesquiterpene lactones with an α-methylene-γ-lactone moiety, dehydrocostus lactone (DHCL), costunolide, santamarine, and a novel compound denoted artabolide [3-hydroxy-4,6,7(H)-germacra-1(10),11(13)-dien-6,12-olide] from oriental medicinal Asteraceae plants as novel naturally occurring inhibitors of polar auxin transport detected by the radish hypocotyl bioassay. To investigate the mode of action of natural sesquiterpene lactones on the inhibition of polar auxin transport as well as its relation to the growth of seedlings, the function of DHCL on growth and auxin dynamics in etiolated pea seedlings was studied intensively. DHCL reduced polar auxin transport in a dose-dependent manner together with the inhibition of the accumulation of mRNA of <em>PsAUX1</em> and <em>PsPIN1</em> genes encoding influx and efflux carrier proteins of auxin, respectively. DHCL applied to the apical hook region as a lanolin paste substantially inhibited elongation growth in the subapical region of epicotyls in intact etiolated pea seedlings, coupled with a significant reduction of endogenous levels of indole-3-acetic acid (IAA). DHCL also revealed the inhibition of IAA-induced cell elongation in etiolated pea epicotyl segments by affecting IAA-induced changes in the mechanical properties of cell walls. These facts suggest that germacranolide-type sesquiterpene lactones with an α-methylene-γ-lactone moiety affect the expression of <em>PsAUX1</em> and <em>PsPINs</em> genes, and then inhibit polar auxin transport and reduce endogenous levels of IAA necessary for stem growth in etiolated pea seedlings. These compounds are also suggested to show the inhibitory effects on auxin action in pea stem growth.

scholarly journals Isolation and identification of polar auxin transport inhibitors from Saussurea costus and Atractylodes japonica

2017 ◽  
Vol 70 (3) ◽  
Author(s):  
Yuta Toda ◽  
Hideyuki Shigemori ◽  
Junichi Ueda ◽  
Kensuke Miyamoto
Keyword(s):  
Auxin Transport ◽  
Polar Auxin Transport ◽  
Inhibitory Effects ◽  
Medicinal Species ◽  
Isolation And Identification ◽  
Naturally Occurring ◽  
Structure Activity ◽  
Atractylodes Japonica ◽  
Transport Inhibitors ◽  
Dehydrocostus Lactone

An intensive survey of naturally-occurring regulators of polar auxin transport (PAT) was conducted in two oriental medicinal species from the Asteraceae, <em>Saussurea costus</em> and <em>Atractylodes japonica</em>, using the radish hypocotyl bioassay system and physicochemical analyses. Costunolide and santamarine were identified as well as dehydrocostus lactone from <em>S. costus</em> roots, and atractylenolide II and (+)-eudesma-4(14),7(11)-dien-8-one from <em>Atractylodes japonica</em> rhizomes as physiologically novel compounds possessing inhibitory activities of PAT. Costunolide and santamarine showed ca. 40% inhibition of PAT in the radish hypocotyl segments at a dose of 2.5 μg/plant and 1 μg/plant, respectively. Inhibitory effects of atractylenolide II and (+)-eudesma-4(14),7(11)-dien-8-one were ca. 10 times lower than those of costunolide and santamarine. Structure–activity relationships and possible mechanisms to inhibit PAT are also discussed.

Enhancement of polar auxin transport by cycloheximide in etiolated pea seedlings

Plant Science ◽  
1999 ◽  
Vol 142 (2) ◽  
pp. 173-181 ◽  
Author(s):  
Myung Hee Nam ◽  
Seung-Eun Oh ◽  
Bin G. Kang
Keyword(s):  
Auxin Transport ◽  
Polar Auxin Transport ◽  
Pea Seedlings

scholarly journals Membrane Sterol Composition in Arabidopsis thaliana Affects Root Elongation via Auxin Biosynthesis

2021 ◽  
Vol 22 (1) ◽  
pp. 437
Author(s):  
Meng Wang ◽  
Panpan Li ◽  
Yao Ma ◽  
Xiang Nie ◽  
Markus Grebe ◽  
...  
Keyword(s):  
Root Elongation ◽  
Auxin Transport ◽  
Sterol Composition ◽  
Polar Auxin Transport ◽  
Sterol Biosynthesis ◽  
Auxin Biosynthesis ◽  
Root Tip ◽  
Auxin Signaling ◽  
Auxin Response ◽  
Short Root

Plant membrane sterol composition has been reported to affect growth and gravitropism via polar auxin transport and auxin signaling. However, as to whether sterols influence auxin biosynthesis has received little attention. Here, by using the sterol biosynthesis mutant cyclopropylsterol isomerase1-1 (cpi1-1) and sterol application, we reveal that cycloeucalenol, a CPI1 substrate, and sitosterol, an end-product of sterol biosynthesis, antagonistically affect auxin biosynthesis. The short root phenotype of cpi1-1 was associated with a markedly enhanced auxin response in the root tip. Both were neither suppressed by mutations in polar auxin transport (PAT) proteins nor by treatment with a PAT inhibitor and responded to an auxin signaling inhibitor. However, expression of several auxin biosynthesis genes TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS1 (TAA1) was upregulated in cpi1-1. Functionally, TAA1 mutation reduced the auxin response in cpi1-1 and partially rescued its short root phenotype. In support of this genetic evidence, application of cycloeucalenol upregulated expression of the auxin responsive reporter DR5:GUS (β-glucuronidase) and of several auxin biosynthesis genes, while sitosterol repressed their expression. Hence, our combined genetic, pharmacological, and sterol application studies reveal a hitherto unexplored sterol-dependent modulation of auxin biosynthesis during Arabidopsis root elongation.

scholarly journals Lupeol Accumulation Correlates with Auxin in the Epidermis of Castor

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2978
Author(s):  
Donghai Li ◽  
Cheng Pan ◽  
Jianjun Lu ◽  
Wajid Zaman ◽  
Huayan Zhao ◽  
...  
Keyword(s):  
Auxin Transport ◽  
Biosynthesis Pathway ◽  
Comparative Transcriptome ◽  
Hormone Activity ◽  
Promoter Regions ◽  
Pentacyclic Triterpene ◽  
Large Numbers ◽  
Genes Encoding ◽  
Low Levels ◽  
Underlying Mechanisms

Lupeol, a natural lupane-type pentacyclic triterpene, possesses various pharmacological properties, and its production attracts attention. Significant quantities of lupeol are deposited on the castor aerial organ surface and are easily extractable as a predominant wax constituent. Thus, castor might be considered as a potential bioreactor for the production of lupeol. The lupeol biosynthesis pathway is well known, but how it is regulated remains largely unknown. Among large numbers of castor cultivars, we targeted one accession line (337) with high levels of lupeol on its stem surface and low levels thereof on its hypocotyl surface, implicating that lupeol synthesis is differentially regulated in the two organs. To explore the underlying mechanisms, we did comparative transcriptome analysis of the first internode of 337 stem and the upper hypocotyl. Our results show that large amounts of auxin-related genes are differentially expressed in both parts, implying some possible interactions between auxin and lupeol production. We also found that several auxin-responsive cis-elements are present in promoter regions of HMGR and LUS genes encoding two key enzymes involved in lupeol production. Furthermore, auxin treatments apparently induced the expression levels of RcHMGR and RcLUS. Furthermore, we observed that auxin treatment significantly increased lupeol contents, whereas inhibiting auxin transport led to an opposite phenotype. Our study reveals some relationships between hormone activity and lupeol synthesis and might provide a promising way for improving lupeol yields in castor.

Antidiabetic agent pioglitazone enhances adipocyte differentiation of 3T3-F442A cells

1993 ◽  
Vol 264 (6) ◽  
pp. C1600-C1608 ◽  
Author(s):  
T. Sandouk ◽  
D. Reda ◽  
C. Hofmann
Keyword(s):  
Cell Differentiation ◽  
Energy Homeostasis ◽  
Combined Treatment ◽  
Transcript Abundance ◽  
Dependent Manner ◽  
Antidiabetic Agent ◽  
Triglyceride Accumulation ◽  
Genes Encoding ◽  
Lower Plasma Glucose ◽  
Triglyceride Content

Adipocytes play an important role in normal physiology as a major site for systemic energy homeostasis. In disorders such as diabetes, adipocyte function is markedly altered. In this study, we investigated the effect of pioglitazone, a novel antidiabetic agent known to lower plasma glucose in animal models of diabetes mellitus, on cellular differentiation and expression of adipose-specific genes. Treatment of confluent 3T3-F442A preadipocyte cultures for 7 days with pioglitazone (Pio; 1 microM) and insulin (Ins; 0.17 microM) resulted in > 95% cell differentiation into lipid-accumulating adipocytes in comparison with 60-80% cell differentiation by treatment with either agent alone. Analysis of triglyceride accumulation showed increases of triglyceride content over time above untreated preadipocytes by treatment of the cells with Ins, Pio, and especially with Ins + Pio. Basal glucose transport, as measured by cellular uptake of 2-deoxy-D-[14C]glucose, was likewise enhanced in a time-dependent manner by treatment of preadipocytes with Ins, Pio, or Ins + Pio, such that a synergistic effect resulted from the combined treatment with both agents. It was further determined that RNA transcript abundance for genes encoding glucose transporters GLUT-1 and GLUT-4, as well as the adipose-specific genes encoding adipsin and aP2, were increased by the Ins, Pio, or Ins + Pio treatment. Taken together, these findings indicate that pioglitazone is a potent adipogenic agent. By promoting differentiation, this agent may move cells into a state active for glucose uptake, storage, and metabolism.

Inhibition of TNF-α-Induced Inflammation by Sesquiterpene Lactones from Saussurea lappa and Semi-Synthetic Analogues

Planta Medica ◽  
2017 ◽  
Vol 84 (05) ◽  
pp. 329-335 ◽  
Author(s):  
Siwattra Choodej ◽  
Khanitha Pudhom ◽  
Tohru Mitsunaga
Keyword(s):  
High Efficiency ◽  
Sesquiterpene Lactones ◽  
Significant Activity ◽  
Synthetic Analogues ◽  
Necrosis Factor Alpha ◽  
Saussurea Lappa ◽  
Tnf Α ◽  
Ic50 Values ◽  
Reduced Toxicity ◽  
Dehydrocostus Lactone

We investigated the tumor necrosis factor-alpha (TNF-α) inhibitory activity of sesquiterpenes from Saussurea lappa root extracts. According to the hexane and EtOAc extracts showing significant activity with IC50 values of 0.5 and 1.0 µg/mL, respectively, chromatographic fractionation of the extracts was performed and led to the isolation of 10 sesquiterpenes (1–10). Costunolide (1), a major compound, and dehydrocostus lactone (4) exhibited high efficiency in decreasing TNF-α levels, with IC50 values of 2.05 and 2.06 µM, respectively. In addition, sesquiterpene analogues were synthesized to establish their structure-activity relationship (SAR) profile. Among the semi-synthetic analogues, compounds 6a and 16 showed the most potent activity with IC50 values of 1.84 and 1.97 µM, respectively. More importantly, compound 6a showed less toxicity than costunolide and 16. These results provided the first SAR profile of sesquiterpene lactones and indicated that the α-methylene-γ-lactone moiety plays a crucial role in TNF-α inhibition. Additionally, the epoxide derivative 6a might represent a lead compound for further anti-TNF-α therapies, owing to its potent activity and reduced toxicity.

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