scholarly journals Regioselectivity of glucosylation of caffeic acid by a UDP-glucose:glucosyltransferase is maintained in planta1

2003 ◽  
Vol 373 (3) ◽  
pp. 987-992 ◽  
Author(s):  
Eng-Kiat LIM ◽  
Gillian S. HIGGINS ◽  
Yi LI ◽  
Dianna J. BOWLES
Keyword(s):  
Enzyme Activity ◽  
Caffeic Acid ◽  
Northern Blot Analysis ◽  
Transgenic Arabidopsis ◽  
Structural Features ◽  
Cauliflower Mosaic Virus ◽  
Leaf Extracts ◽  
Transgenic Lines ◽  
First Time

Caffeic acid is a phenylpropanoid playing an important role in the pathways leading to lignin synthesis and the production of a wide variety of secondary metabolites. The compound is also an antioxidant and has potential utility as a general protectant against free radicals. Three glucosylated forms of caffeic acid are known to exist: the 3-O- and 4-O-glucosides and the glucose ester. This study describes for the first time a glucosyltransferase [UDP-glucose:glucosyltransferase (UGT)] that is specific for the 3-hydroxyl, and not the 4-hydroxyl, position of caffeic acid. The UGT sequence of Arabidopsis, UGT71C1, has been expressed as a recombinant fusion protein in Escherichia coli, purified and assayed against a range of substrates in vitro. The assay confirmed that caffeic acid as the preferred substrate when compared with other hydroxycinnamates, although UGT71C1 also exhibited substantial activity towards flavonoid substrates, known to have structural features that can be recognized by many different UGTs. The expression of UGT71C1 in transgenic Arabidopsis was driven by the constitutive cauliflower mosaic virus 35 S (CaMV35S) promoter. Nine independent transgenic lines were taken to homozygosity and characterized by Northern-blot analysis, assay of enzyme activity in leaf extracts and HPLC analysis of the glucosides. The level of expression of UGT71C1 was enhanced considerably in several lines, leading to a higher level of the corresponding enzyme activity and a higher level of caffeoyl-3-O-glucoside. The data are discussed in the context of the utility of UGTs for natural product biotransformations.

scholarly journals Cecropia pachystachya Leaves Present Potential to Be Used as New Ingredient for Antiaging Dermocosmetics

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Maria Fernanda Fernandes ◽  
Jessica Leiras Mota Conegundes ◽  
Nícolas de Castro Campos Pinto ◽  
Luiz Gustavo de Oliveira ◽  
Jair Adriano Kopke de Aguiar ◽  
...  
Keyword(s):  
Biological Activities ◽  
Thiobarbituric Acid ◽  
Skin Aging ◽  
Total Phenolic ◽  
Leaf Extracts ◽  
Hek 293 ◽  
Human Embryonic Kidney Cells ◽  
Glycation End Products ◽  
First Time

Several biological activities have been reported for leaf extracts of Cecropia pachystachya species, including antioxidant and wound healing activities. This study aims to report, for the first time, the antiaging potential of the hydroethanolic (HE) and the ethanolic (EE) extracts obtained from the leaves of C. pachystachya using different in vitro assays. Both HE and EE presented relevant antioxidant capacity in different models, including phosphomolybdenum, 1,1-diphenyl-2-picryl-hydrazyl (DPPH), carotene/linoleic acid bleaching, and thiobarbituric acid reactive substances (TBARS) assays. Their ability to prevent the production of advanced glycation end products (AGEs) was also evaluated, and both extracts showed important activity, especially HE. The extracts also stimulated the fibroblasts proliferation in vitro, specialized cells that produce several mediators which maintain the skin integrity and youthfulness. Cytotoxicity of the extracts was not observed for this lineage or HEK-293, human embryonic kidney cells widely used to evaluate cytotoxicity of chemical compounds. HE also exhibited the ability to inhibit the collagenase (metalloproteinase MMP-2) and elastase activities. The total phenolic and flavonoids contents were also determined. HPLC analysis revealed the presence of the flavonoids orientin and iso-orientin, which were quantified to be used as chemical markers. The results suggested that the extracts of C. pachystachya leaves present the potential to be used in dermocosmetic formulations to prevent the skin aging process, which attracts the attention of pharmaceutical companies and researchers interested in the development of novel ingredients likely to be used as active principles in antiaging products.

scholarly journals BTCI enhances guanylin-induced natriuresis and promotes renal glomerular and tubular effects

2008 ◽  
Vol 68 (1) ◽  
pp. 149-154 ◽  
Author(s):  
AF. Carvalho ◽  
MS. Santos-Neto ◽  
HSA. Monteiro ◽  
SM. Freitas ◽  
L. Morhy ◽  
...  
Keyword(s):  
Filtration Rate ◽  
Rat Kidney ◽  
Structural Features ◽  
Urine Flow ◽  
Renal Metabolism ◽  
Chymotrypsin Inhibitor ◽  
Electrolyte Homeostasis ◽  
Perfused Rat Kidney ◽  
First Time

Guanylin and uroguanylin are small cysteine-rich peptides involved in the regulation of fluid and electrolyte homeostasis through binding and activation of guanylyl cyclases signaling molecules expressed in intestine and kidney. Guanylin is less potent than uroguanylin as a natriuretic agent and is degraded in vitro by chymotrypsin due to unique structural features in the bioactive moiety of the peptide. Thus, the aim of this study was to verify whether or not guanylin is degraded by chymotrypsin-like proteases present in the kidney brush-border membranes. The isolated perfused rat kidney assay was used in this regard. Guanylin (0.2 µM) induced no changes in kidney function. However, when pretreated by the black-eyed pea trypsin and chymotrypsin inhibitor (BTCI - 1.0 µM; guanylin - 0.2 µM) it promoted increases in urine flow (deltaUF of 0.25 ± 0.09 mL.g-1/min, P < 0.05) and Na+ excretion (% delta ENa+ of 18.20 ± 2.17, P < 0.05). BTCI (1.0 µM) also increased %ENa+ (from 22.8 ± 1.30 to 34.4 ± 3.48, P < 0.05, 90 minutes). Furthermore, BTCI (3.0 µM) induced increases in glomerular filtration rate (GFR; from 0.96 ± 0.02 to 1.28 0.02 mL.g-1/min, P < 0.05, 60 minutes). The present paper strongly suggests that chymotrypsin-like proteases play a role in renal metabolism of guanylin and describes for the first time renal effects induced by a member of the Bowman-Birk family of protease inhibitors.

scholarly journals ABAS1 from soybean is a 1R-subtype MYB transcriptional repressor that enhances ABA sensitivity

2020 ◽  
Vol 71 (10) ◽  
pp. 2970-2981
Author(s):  
Yee-Shan Ku ◽  
Meng Ni ◽  
Nacira B Muñoz ◽  
Zhixia Xiao ◽  
Annie Wing-Yi Lo ◽  
...  
Keyword(s):  
Target Gene ◽  
Transgenic Arabidopsis ◽  
Expression Patterns ◽  
Transcriptional Repressor ◽  
Aba Sensitivity ◽  
Reporter Systems ◽  
First Time ◽  
Reciprocal Expression

Abstract Transcription factors (TFs) help plants respond to environmental stresses by regulating gene expression. Up till now, studies on the MYB family of TFs have mainly focused on the highly abundant R2R3-subtype. While the less well-known 1R-subtype has been generally shown to enhance abscisic acid (ABA) sensitivity by acting as transcriptional activators, the mechanisms of their functions are unclear. Here we identified an ABA sensitivity-associated gene from soybean, ABA-Sensitive 1 (GmABAS1), of the 1R-subtype of MYB. Using the GFP-GmABAS1 fusion protein, we demonstrated that GmABAS1 is localized in the nucleus, and with yeast reporter systems, we showed that it is a transcriptional repressor. We then identified the target gene of GmABAS1 to be Glyma.01G060300, an annotated ABI five-binding protein 3 and showed that GmABAS1 binds to the promoter of Glyma.01G060300 both in vitro and in vivo. Furthermore, Glyma.01G060300 and GmABAS1 exhibited reciprocal expression patterns under osmotic stress, inferring that GmABAS1 is a transcriptional repressor of Glyma.01G060300. As a further confirmation, AtAFP2, an orthologue of Glyma.01G060300, was down-regulated in GmABAS1-transgenic Arabidopsis thaliana, enhancing the plant’s sensitivity to ABA. This is the first time a 1R-subtype of MYB from soybean has been reported to enhance ABA sensitivity by acting as a transcriptional repressor.

scholarly journals Paxillus involutus Forms an Ectomycorrhizal Symbiosis and Enhances Survival of PtCOMT-modified Betula pendula in vitro

2008 ◽  
Vol 57 (1-6) ◽  
pp. 235-242 ◽  
Author(s):  
H. Tiimonen ◽  
T. Aronen ◽  
T. Laakso ◽  
P. Saranpää ◽  
V. Chiang ◽  
...  
Keyword(s):  
Populus Tremuloides ◽  
Betula Pendula ◽  
Root Formation ◽  
Lateral Roots ◽  
Cauliflower Mosaic Virus ◽  
35S Promoter ◽  
Paxillus Involutus ◽  
Transgenic Lines ◽  
G Ratio

Abstract The ability of the PtCOMT (caffeate/5-hydroxyferulate O-methyltransferase from Populus tremuloides L.) - modified Betula pendula Roth. lines to form symbiosis with an ectomycorrhizal (ECM) fungus Paxillus involutus Batsch Fr. was studied in vitro. Lignin precursor gene PtCOMT was introduced into two B. pendula clones under the control of the cauliflower mosaic virus 35S promoter or the promoter of the sunflower polyubiquitin gene UbB1. Of the four transgenic lines, one 35SPtCOMT line (23) had a decreased syringyl/guaiacyl (S/G) ratio of root lignin, and two UbB1-PtCOMT lines (110 and 130) retarded root growth compared to the control clone. Both control clones and all transgenic lines were able to form ECMs with P. involutus, but the transgenic lines differed from the controls in the characteristics of the ECMs. The number of lateral roots covered with fungal hyphae and/or development of a Hartig net (HN) were reduced in line 23 with a decreased S/G ratio, and in lines 110 and 130 with slower root formation and changed root morphology, respectively. However, line 23 benefited more from the inoculation in lateral root formation than the control, and in lines 110 and 130 the percentage of viable plants increased most due to inoculation. The results show that B. pendula plants genetically transformed with the lignin gene PtCOMT could form mycorrhizal symbiosis regardless of changes in either the root S/G ratio or development. The benefits of the symbiosis were variable even in the closed in vitro system, and dependent on the clone or transgenic line and the ECM fungal symbiont.

scholarly journals Glutamine synthetase localization in cortisol-induced chick embryo retinas.

1980 ◽  
Vol 84 (3) ◽  
pp. 803-807 ◽  
Author(s):  
M D Norenberg ◽  
K Dutt ◽  
L Reif-Lehrer
Keyword(s):  
Enzyme Activity ◽  
Glutamine Synthetase ◽  
In Ovo ◽  
Immunohistochemical Technique ◽  
Cell Localization ◽  
Chick Retina ◽  
Age Dependent ◽  
Induced Changes ◽  
First Time

We report here for the first time, in chick retina, Muller cell localization of glutamine synthetase (GS) activity by an immunohistochemical technique, in agreement with previous reports of glial localization of this enzyme in rat brain and retina. Age-dependent changes in the endogenous enzyme activity as well as cortisol-induced changes in GS activity, both in ovo and in vitro, measured biochemically, reflect the changes observed by staining.

scholarly journals Phytochemical Profile and Biological Properties of Colchicum triphyllum (Meadow Saffron)

Foods ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 457 ◽  
Author(s):  
Biancamaria Senizza ◽  
Gabriele Rocchetti ◽  
Murat Ali Okur ◽  
Gokhan Zengin ◽  
Evren Yıldıztugay ◽  
...  
Keyword(s):  
High Performance ◽  
Biological Activities ◽  
Reducing Power ◽  
Extraction Methods ◽  
Biological Properties ◽  
Leaf Extracts ◽  
Antioxidant Power ◽  
Phytochemical Profile ◽  
First Time

In this work, the phytochemical profile and the biological properties of Colchicum triphyllum (an unexplored Turkish cultivar belonging to Colchicaceae) have been comprehensively investigated for the first time. Herein, we focused on the evaluation of the in vitro antioxidant and enzyme inhibitory effects of flower, tuber, and leaf extracts, obtained using different extraction methods, namely maceration (both aqueous and methanolic), infusion, and Soxhlet. Besides, the complete phenolic and alkaloid untargeted metabolomic profiling of the different extracts was investigated. In this regard, ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) allowed us to putatively annotate 285 compounds when considering the different matrix extracts, including mainly alkaloids, flavonoids, lignans, phenolic acids, and tyrosol equivalents. The most abundant polyphenols were flavonoids (119 compounds), while colchicine, demecolcine, and lumicolchicine isomers were some of the most widespread alkaloids in each extract analyzed. In addition, our findings showed that C. triphyllum tuber extracts were a superior source of both total alkaloids and total polyphenols, being on average 2.89 and 10.41 mg/g, respectively. Multivariate statistics following metabolomics allowed for the detection of those compounds most affected by the different extraction methods. Overall, C. triphyllum leaf extracts showed a strong in vitro antioxidant capacity, in terms of cupric reducing antioxidant power (CUPRAC; on average 96.45 mg Trolox Equivalents (TE)/g) and ferric reducing antioxidant power (FRAP) reducing power (on average 66.86 mg TE/g). Interestingly, each C. triphyllum methanolic extract analyzed (i.e., from tuber, leaf, and flower) was active against the tyrosinase in terms of inhibition, recording the higher values for methanolic macerated leaves (i.e., 125.78 mg kojic acid equivalent (KAE)/g). On the other hand, moderate inhibitory activities were observed against AChE and α-amylase. Strong correlations (p < 0.01) were also observed between the phytochemical profiles and the biological activities determined. Therefore, our findings highlighted, for the first time, the potential of C. triphhyllum extracts in food and pharmaceutical applications.

Biotransformation of caffeic acid by Momordica charantia peroxidase

2008 ◽  
Vol 86 (8) ◽  
pp. 821-830 ◽  
Author(s):  
Xiang Wan ◽  
Haili Liu ◽  
Xuefeng Huang ◽  
Jianguang Luo ◽  
Lingyi Kong
Keyword(s):  
Antioxidant Activity ◽  
Caffeic Acid ◽  
2D Nmr ◽  
Momordica Charantia ◽  
The Other ◽  
Oxidative Activity ◽  
Nmr Techniques ◽  
New Compounds ◽  
First Time

Biotransformation of caffeic acid with H2O2/Momordica charantia peroxidase at pH 5.0, 25 °C in the presence of acetone has resulted in the isolation of three caffeic acid trimers 1–3, five caffeic acid dimers 4–8, and one monomer 9. Among them, seven (1–7) are new compounds, and two (8 and 9) are known compounds, including one compound (9), which was obtained by biotransformation for the first time. The structures were established by 2D NMR techniques, such as HSQC, HMBC, and NOESY measurements. The possible mechanism for the formation of the products is also discussed. This is the first time that caffeic acid trimers have been obtained through the biotransformation of catalyzed by peroxidase in vitro. Compound 5 has shown much stronger anti-oxidative activity than the other caffeic acid polymers obtained.Key words: Momordica charantia peroxidase, caffeic acid, polymers of caffeic acid, biotransformation, antioxidant activity.

scholarly journals Translation of cIAP2 mRNA Is Mediated Exclusively by a Stress-Modulated Ribosome Shunt

2008 ◽  
Vol 28 (6) ◽  
pp. 2011-2022 ◽  
Author(s):  
Kyle W. Sherrill ◽  
Richard E. Lloyd
Keyword(s):  
Translation Initiation ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Structural Features ◽  
Cauliflower Mosaic Virus ◽  
Internal Ribosome Entry ◽  
Virus Rna ◽  
Selective Mutation ◽  
Upstream Augs

ABSTRACT During cellular stress, translation persists or increases for a number of stress-responsive proteins, including cellular inhibitor of apoptosis 2 (cIAP2). The cIAP2 transcript includes a very long (2.78-kb) 5′ untranslated region (UTR) with an unusually high number of upstream AUGs (uAUGs), i.e., 64, and a stable predicted secondary structure (ΔG ≅ −620 kcal/mol) that should completely block conventional scanning-dependent translation initiation. This region did not facilitate internal ribosome entry in vitro or when RNA reporter transcripts were transfected into cells. However, several structural features within the cIAP2 5′ UTR were observed to be nearly identical to those required for ribosome shunting in cauliflower mosaic virus RNA and are well conserved in cIAP2 orthologs. Selective mutation revealed that the cIAP2 mRNA mediates translation exclusively via ribosome shunting that bypasses 62 uAUGs. In addition, shunting efficiency was altered by stress and was greatly facilitated by a conserved RNA folding domain (1,470 to 1,877 nucleotides upstream) in a region not scanned by shunting ribosomes. This arrangement suggests that regulation of cIAP2 shunting may involve recruitment of RNA binding proteins to modulate the efficiency of translation initiation.

scholarly journals 3-Nitropropionic acid oxidase from horseshoe vetch (Hippocrepis comosa): a novel plant enzyme

1999 ◽  
Vol 340 (2) ◽  
pp. 491-495 ◽  
Author(s):  
Charles R. HIPKIN ◽  
Mansour A. SALEM ◽  
Deborah SIMPSON ◽  
Stephen J. WAINWRIGHT
Keyword(s):  
Enzyme Activity ◽  
Acid Oxidase ◽  
Leaf Extracts ◽  
Nitropropionic Acid ◽  
A Subunit ◽  
High Concentrations ◽  
Nitrate And Nitrite ◽  
Plant Enzyme ◽  
3 Nitropropionic Acid

A novel enzyme that catalyses the oxygen-dependent oxidation of 3-nitropropionic acid (3NPA) to malonate semialdehyde, nitrate, nitrite and H2O2 has been purified from leaf extracts of the horseshoe vetch, Hippocrepis comosa, and named 3NPA oxidase. The enzyme is a flavoprotein with a subunit molecular mass of 36 kDa containing 1 molecule of FMN and exhibits little specificity for all nitroalkanes tested other than 3NPA (apparent Km 620 μM). The maximum enzyme activity in vitro was expressed at pH 4.8 and was inhibited strongly by the products nitrate and nitrite. 3NPA oxidase activity was detected in green shoots, which also contain high concentrations of 3NPA, from plants grown with nitrate, ammonium or N2 as sources of nitrogen. Enzyme activity was absent from roots and cell cultures, neither of which accumulate high levels of 3NPA.

scholarly journals Comparative Risk Assessment of Three Native Heliotropium Species in Israel

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 689
Author(s):  
Jakob A. Shimshoni ◽  
Shimon Barel ◽  
Patrick P. J. Mulder
Keyword(s):  
Dry Weight ◽  
Structural Features ◽  
Simultaneous Exposure ◽  
Major Organ ◽  
Comparative Risk ◽  
Toxic Potential ◽  
First Time ◽  
Prevalent Species

Pyrrolizidine alkaloids (PAs) are genotoxic carcinogenic phytotoxins mostly prevalent in the Boraginaceae, Asteraceae and Fabaceae families. Heliotropium species (Boraginaceae) are PA-producing weeds, widely distributed in the Mediterranean region, that have been implicated with lethal intoxications in livestock and humans. In Israel, H. europaeum, H. rotundifolium and H. suaveolens are the most prevalent species. The toxicity of PA-producing plants depends on the PA concentration and composition. PAs occur in plants as mixtures of dozens of various PA congeners. Hence, the risk arising from simultaneous exposure to different congeners has to be evaluated. The comparative risk evaluation of the three Heliotropium species was based on recently proposed interim relative potency (iREP) factors, which take into account certain structural features as well as in vitro and in vivo toxicity data obtained for several PAs of different classes. The aim of the present study was to determine the PA profile of the major organ parts of H. europaeum, H. rotundifolium and H. suaveolens in order to assess the plants’ relative toxic potential by utilizing the iREP concept. In total, 31 different PAs were found, among which 20 PAs were described for the first time for H. rotundifolium and H. suaveolens. The most prominent PAs were heliotrine-N-oxide, europine-N-oxide and lasiocarpine-N-oxide. Europine-N-oxide displayed significant differences among the three species. The PA levels ranged between 0.5 and 5% of the dry weight. The flowers of the three species were rich in PAs, while the PA content in the root and flowers of H. europaeum was higher than that of the other species. H. europaeum was found to pose a higher risk to mammals than H. rotundifolium, whereas no differences were found between H. europaeum and H. suaveolens as well as H. suaveolens and H. rotundifolium.

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