Autotoxic compounds from rhizosphere soil of lanzhou lily extracts: Identification and biological activity

2021 ◽  
Vol 53 (1) ◽  
pp. 111-126
Author(s):  
Y. F. Huang ◽  
E. H. Zhang ◽  
X. H. Zhang ◽  
Q. Wang ◽  
H. Z. Wang ◽  
...  
Keyword(s):  
Antioxidant Enzyme ◽  
Seedling Growth ◽  
Rhizosphere Soil ◽  
Gas Chromatography Mass Spectrometry ◽  
Antioxidant Enzyme Activities ◽  
Photosynthetic Parameters ◽  
Inhibitory Effects ◽  
Low Concentrations ◽  
High Concentrations ◽  
Lanzhou Lily

We investigated the autotoxicity of Lanzhou lily rhizosphere soil with different cultivation years. The allelochemicals in such soils were isolated and identified by gas chromatography-mass spectrometry (GC-MS). Based on our earlier studies, the antioxidant 2246 and dioctyl terephthalate were found in lily sick soil were used in pot experiments determine to their autotoxic effects on the Lanzhou lily seedlings growth, photosynthetic parameters and antioxidant enzyme activities in seedling leaves. The content of antioxidant 2246 and dioctyl terephthalate was determined by GC-MS in rhizosphere soil of different cultivation years. The aqueous extracts of Lanzhou lily rhizosphere soil promoted the growth of its own seedlings at 0.2 mg·mL-1, however, the concentrations > 2 mg·mL-1 were inhibitory. The longer the cultivation period (1-yr, 2-yr and 4-yr), the stronger were the inhibitory effects. In rhizosphere soils of 1-yr, 2-yr and 4-yr ; 8,: 15 and 18 compounds were identified, respectively. The identified compounds were camphor, 3-hydroxy-4-methoxy-benzaldehyde, 2,4-bis(1,1- dimethylethyl)-phenol, tributyl phosphate, dibutyl phthalate, antioxidant 2246 and dioctyl terephthalater and these are reported as allelochemicals. The pot experiment results showed that low concentrations of antioxidant 2246 stimulated the seedling growth but high concentrations were inhibitory, while all concentrations of dioctyl terephthalater inhibited the seedling growth. At 100 mg·mL-1, the antioxidant 2246 and dioctyl terephthalate significantly inhibited the photosynthesis and antioxidant enzyme activity in leaves (P <0.05). Furthermore, the content of these two compounds in soils increased with the increase of cultivation years. These results suggested that allelochemicals accumulated in replanted soil contributed to the autotoxicity of Lanzhou lily in rhizosphere soil.

In Vitro Effects of Ethanol on Rabbit Platelet Aggregation, Secretion of Granule Contents, and Cyclic AMP Levels in the Presence of Prostacyclin

1989 ◽  
Vol 61 (02) ◽  
pp. 254-258 ◽  
Author(s):  
Margaret L Rand ◽  
Peter L Gross ◽  
Donna M Jakowec ◽  
Marian A Packham ◽  
J Fraser Mustard
Keyword(s):  
Cyclic Amp ◽  
Inhibitory Effect ◽  
Rabbit Platelet ◽  
Inhibitory Effects ◽  
Low Concentrations ◽  
Rabbit Platelets ◽  
High Concentrations ◽  
In Vitro Effects ◽  
Aggregation Of Platelets

SummaryEthanol, at physiologically tolerable concentrations, inhibits platelet responses to low concentrations of collagen or thrombin, but does not inhibit responses of washed rabbit platelets stimulated with high concentrations of ADP, collagen, or thrombin. However, when platelet responses to high concentrations of collagen or thrombin had been partially inhibited by prostacyclin (PGI2), ethanol had additional inhibitory effects on aggregation and secretion. These effects were also observed with aspirin- treated platelets stimulated with thrombin. Ethanol had no further inhibitory effect on aggregation of platelets stimulated with ADP, or the combination of ADP and epinephrine. Thus, the inhibitory effects of ethanol on platelet responses in the presence of PGI2 were very similar to its inhibitory effects in the absence of PGI2, when platelets were stimulated with lower concentrations of collagen or thrombin. Ethanol did not appear to exert its inhibitory effects by increasing cyclic AMP above basal levels and the additional inhibitory effects of ethanol in the presence of PGI2 did not appear to be brought about by further increases in platelet cyclic AMP levels.

Inactivation of Toluene 2-Monooxygenase in Burkholderia cepacia G4 by Alkynes

1999 ◽  
Vol 65 (2) ◽  
pp. 632-639 ◽  
Author(s):  
Chris M. Yeager ◽  
Peter J. Bottomley ◽  
Daniel J. Arp ◽  
Michael R. Hyman
Keyword(s):  
Gas Phase ◽  
Burkholderia Cepacia ◽  
Dependent Manner ◽  
Inhibitory Effects ◽  
Specific Mechanism ◽  
Monooxygenase Activity ◽  
First Order Kinetics ◽  
Low Concentrations ◽  
High Concentrations ◽  
Dependent Growth

ABSTRACT High concentrations of acetylene (10 to 50% [vol/vol] gas phase) were required to inhibit the growth of Burkholderia cepaciaG4 on toluene, while 1% (vol/vol) (gas phase) propyne or 1-butyne completely inhibited growth. Low concentrations of longer-chain alkynes (C5 to C10) were also effective inhibitors of toluene-dependent growth, and 2- and 3-alkynes were more potent inhibitors than their 1-alkyne counterparts. Exposure of toluene-grownB. cepacia G4 to alkynes resulted in the irreversible loss of toluene- and o-cresol-dependent O2 uptake activities, while acetate- and 3-methylcatechol-dependent O2 uptake activities were unaffected. Toluene-dependent O2 uptake decreased upon the addition of 1-butyne in a concentration- and time-dependent manner. The loss of activity followed first-order kinetics, with apparent rate constants ranging from 0.25 min−1 to 2.45 min−1. Increasing concentrations of toluene afforded protection from the inhibitory effects of 1-butyne. Furthermore, oxygen, supplied as H2O2, was required for inhibition by 1-butyne. These results suggest that alkynes are specific, mechanism-based inactivators of toluene 2-monooxygenase inB. cepacia G4, although the simplest alkyne, acetylene, was relatively ineffective compared to longer alkynes. Alkene analogs of acetylene and propyne—ethylene and propylene—were not inactivators of toluene 2-monooxygenase activity in B. cepacia G4 but were oxidized to their respective epoxides, with apparentKs and V max values of 39.7 μM and 112.3 nmol min−1 mg of protein−1 for ethylene and 32.3 μM and 89.2 nmol min−1 mg of protein−1 for propylene.

Intracellular mediators of bombesin action on rat pancreatic acinar cells

1991 ◽  
Vol 260 (6) ◽  
pp. G858-G864 ◽  
Author(s):  
T. Matozaki ◽  
W. Y. Zhu ◽  
Y. Tsunoda ◽  
B. Goke ◽  
J. A. Williams
Keyword(s):  
Time Course ◽  
Pancreatic Acinar Cells ◽  
Amylase Secretion ◽  
Inhibitory Effects ◽  
Pancreatic Acini ◽  
Low Concentrations ◽  
Intracellular Messengers ◽  
Early Peak ◽  
High Concentrations ◽  
Intracellular Mediators

The effects of bombesin on physiological responses (amylase secretion, protein synthesis) and intracellular mediators [inositol 1,4,5-trisphosphate (1,4,5–IP3), [Ca2+]i, and diacylglycerol] were studied in isolated rat pancreatic acini and compared with the actions of cholecystokinin (CCK). Bombesin stimulated amylase secretion to the same extent as CCK. However, it failed to reproduce the inhibition of amylase secretion by high concentrations of CCK and likewise did not inhibit incorporation of [3H]leucine into protein in contrast to high concentrations of CCK. Low concentrations of bombesin (1–100 pM) induced repetitive oscillations in [Ca2+]i, whereas higher concentrations of bombesin (1–10 nM) induced a large transient increase in [Ca2+]i followed by a small sustained plateau. Bombesin (1–100 nM) induced an early peak of 1,4,5–IP3 at 5–15 s but was without measurable effect at lower concentrations. These effects on [Ca2+]i and 1,4,5–IP3 were similar to those seen with CCK except that bombesin was approximately 10-fold less potent than CCK. Bombesin induced an increase in acinar 1,2-diacylglycerol with a biphasic time course similar to CCK. However, the magnitude of the response to bombesin was much smaller than the response to CCK. The results suggest that bombesin receptors initiate similar intracellular messengers as does CCK. However, CCK induces a larger increase of diacylglycerol and probably an as yet unidentified messenger responsible for its inhibitory effects.

scholarly journals Allelopathic Effects of Cinnamomum migao on Seed Germination and Seedling Growth of its Associated Species Liquidambar formosana

Forests ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 535
Author(s):  
Deng Wang ◽  
Jingzhong Chen ◽  
Xue Xiong ◽  
Shu Wang ◽  
Jiming Liu
Keyword(s):  
Seed Germination ◽  
Seedling Growth ◽  
Leaf Extract ◽  
Rhizosphere Soil ◽  
Starch Accumulation ◽  
Soil Extracts ◽  
Aqueous Leaf Extract ◽  
Allelopathic Effects ◽  
High Concentrations ◽  
Associated Species

We examined allelopathic effects and underlying mechanisms of Cinnamomum migao on its associated species Liquidambar formosana. We assessed effects of aqueous extracts of C. migao pericarp, leaf, and rhizosphere soil at different concentrations on seed germination, seedling growth, and physiology of L. formosana. All extracts inhibited L. formosana seed germination, with obvious inhibition at high concentrations (50 mg mL−1). All extracts promoted the height and ground diameter of seedlings, with the highest promotion achieved with aqueous leaf extract at a concentration of 1 mg mL−1 and aqueous pericarp and rhizosphere soil extracts at a concentration of 5 mg mL−1. All extracts promoted soluble protein accumulation in L. formosana seedlings, with the highest accumulation achieved with aqueous pericarp extracts. Aqueous leaf extract promoted soluble starch accumulation. Aqueous pericarp extract at concentrations of >10 mg mL−1 significantly increased soluble sugar content. Aqueous leaf and rhizosphere soil extracts at concentrations of >5 mg mL−1 increased proline accumulation. All extracts at concentrations of >1 mg mL−1 significantly increased malondialdehyde content. Aqueous pericarp and rhizosphere soil extracts at concentrations of 10 and 0.5 mg mL−1, respectively, promoted superoxide dismutase activity. Activities of soil urease, polyphenol oxidase, and catalase were significantly increased when the concentration of aqueous pericarp and leaf extracts exceeded 5 mg mL−1, and the activity of soil acid phosphatase significantly increased when the concentration of all extracts were 5 mg mL−1. According to the synthetic allelopathic index, the low- and medium-concentration extracts all showed a promoting effect, whereas high concentrations exhibited obvious inhibitory effects; furthermore, the comprehensive effect value of leaf water extraction was higher than that of the pericarp and rhizosphere soil. Thus, allelopathy can affect the long-term co-existence of C. migao and L. formosana.

Biofilm Growth of Escherichia coli Is Subject to cAMP-Dependent and cAMP-Independent Inhibition

2015 ◽  
Vol 25 (2-3) ◽  
pp. 209-225 ◽  
Author(s):  
Sarah L. Sutrina ◽  
Kia Daniel ◽  
Michael Lewis ◽  
Naomi T. Charles ◽  
Cherysa K.E. Anselm ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Catabolite Repression ◽  
Ph Effects ◽  
Wild Type ◽  
Inhibitory Effects ◽  
Phosphotransferase System ◽  
Biofilm Growth ◽  
E Coli ◽  
Low Concentrations ◽  
High Concentrations

We established that <i>Escherichia coli </i>strain 15 (ATCC 9723) produces both curli and cellulose, and forms robust biofilms. Since this strain is wild type with respect to the phosphoenolpyruvate:sugar phosphotransferase system (PTS), it is an ideal strain in which to investigate the effects of the PTS on the biofilm growth of <i>E. coli</i>. We began by looking into the effects of PTS and non-PTS sugars on the biofilm growth of this strain. All the sugars tested tended to activate biofilm growth at low concentrations but to inhibit biofilm growth at high concentrations. Acidification of the medium was an inhibitory factor in the absence of buffer, but buffering to prevent a pH drop did not prevent the inhibitory effects of the sugars. The concentration at which inhibition set in varied from sugar to sugar. For most sugars, cyclic (c)AMP counteracted the inhibition at the lowest inhibitory concentrations but became ineffective at higher concentrations. Our results suggest that cAMP-dependent catabolite repression, which is mediated by the PTS in <i>E. coli</i>, plays a role in the regulation of biofilm growth in response to sugars. cAMP-independent processes, possibly including Cra, also appear to be involved, in addition to pH effects.

INTERACTIONS BETWEEn PGE2 AND INHIBITORS OF PLATELET AGGREGATION THAT ACT THROUGH cAMP

1987 ◽  
Author(s):  
S J Gray ◽  
S Heptinstall
Keyword(s):  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
Renal Medulla ◽  
Inhibitory Effects ◽  
Guanine Nucleotide Binding Protein ◽  
Camp Phosphodiesterase ◽  
Low Concentrations ◽  
Platelet Receptor ◽  
High Concentrations ◽  
Camp Levels

PGE2 has a biphasic effect on platelet aggregation with low concentrations of the prostaglandin potentiating aggregation and high concentrations inhibiting it. In this investigation we have studied the interaction of PGE2 with agents that inhibit platelet aggregation through an effect on cAMP. The agents chosen raise the level of cAMP in platelets by different mechanisms: PGI2, PGD9 and adenosine combine with specific surface-located receptors and stimulate adenylate cyclase (AC) via a guanine nucleotide-binding protein (GNBP), forskolin stimulates AC directly, and AH-P 719 and DN 9693 inhibit cAMP phosphodiesterase (PDE). ADP-induced platelet aggregation was measured in platelet-rich plasma and cAMP was measured in platelets labelled with 3H-adenine.PGE2 alone potentiated platelet aggregation at concentrations from 10™8 -10™6 M and inhibited aggregation at 10™5M. PGE2 did not reduce cAMP levels at any concentration and increased cAMP levels at concentrations > 10™6 M, profcably by stimulating AC.PGI2 (10™9 -10™8 M), PGD2 (10™7 -5×10™6 M) and adenosine (8×l0™5-2×10™4 M) increased the level of cAMP in platelets and inhibited aggregation these changes were reversed by low concentrations of PGE2 (10™8-10™6M).Forskolin (5×10™6-2.5×10™5M), AH-P 719 (10™7-10™5M) and DN 9693 (5×10™6 -10™5M) increased the level of cAMP in platelets and inhibited aggregation. However, PGE2 did not reverse the inhibitory effects of these particular agents. In contrast, PGE2 potentiated the effects of the agents at all the concentrations of PGE2 that were tested (10™8-10™5M).The different results obtained with PGE2 in combination with agents that act via surface-located receptors compared with agents that stimulate AC directly or act through PDE, suggest that PGE2 may potentiate platelet aggregation by acting at a point between the platelet receptor and AC i.e. GNBP.PGE2 is one of the major prostaglandins synthesised by human microvascular endothelial cells and interstitial cells of the renal medulla. Since it reverses the inhibitory effects of some AC stimulators but adds to those of PDE inhibitors, the latter may have greater potential as anti-thrombotic agents in the micro-circulation and intra-renal circulation.

scholarly journals The Impact on Antioxidant Enzyme Activity and Related Gene Expression Following Adult Zebrafish (Danio rerio) Exposure to Dimethyl Phthalate

Animals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 717
Author(s):  
Bailin Cong ◽  
Cong Liu ◽  
Lujie Wang ◽  
Yingmei Chai
Keyword(s):  
Gene Expression ◽  
Antioxidant Enzyme ◽  
Danio Rerio ◽  
Expression Patterns ◽  
Antioxidant Enzyme Activities ◽  
Dimethyl Phthalate ◽  
Adult Zebrafish ◽  
Initial Exposure ◽  
High Concentrations ◽  
The Impact

Dimethyl phthalate (DMP) is a widespread environmental contaminant that poses potential toxicity risks for animals and humans. However, the toxicological effects of DMP on fish have not been adequately examined. In this study, the acute toxicity, oxidative damage, antioxidant enzyme activities, and relative gene expression patterns were investigated in the liver of adult zebrafish (Danio rerio) exposed to DMP. We found that the lethal concentration (LC50) of DMP for zebrafish after 96 h of exposure was 45.8 mg/L. The zebrafish that were exposed to low, medium and high concentrations of DMP (0.5, 4.6, and 22.9 mg/L, respectively) for 96 h had an increased malondialdehyde (MDA) content and a lower antioxidant capacity compared with the control solvent group. The total superoxide dismutase (SOD) activity was significantly higher than 0 h after initial exposure for 24 h at low concentrations, and then decreased at high concentrations after exposure for 96 h. The catalase (CAT) and glutathione S-transferase (GST) activities were significantly reduced after 96 h of exposure to high concentrations of DMP, with the up- or down-regulation of the related transcriptional expression. These findings indicated that DMP could cause physiological effects in zebrafish by disturbing the expression levels of antioxidant enzymes. These results might contribute to the identification of biomarkers to monitor phthalate pollution.

scholarly journals Differentiation of Amphetamine/Methamphetamine and Other Cross-Immunoreactive Sympathomimetic Amines in Urine Samples by Serial Dilution Testing

2006 ◽  
Vol 52 (4) ◽  
pp. 743-746 ◽  
Author(s):  
Alison Woodworth ◽  
Al N Saunders ◽  
John W Koenig ◽  
Thomas P Moyer ◽  
John Turk ◽  
...  
Keyword(s):  
Dose Response ◽  
Roc Analysis ◽  
Urine Samples ◽  
Gas Chromatography Mass Spectrometry ◽  
Maximum Slope ◽  
Patient Disposition ◽  
Low Concentrations ◽  
High Concentrations ◽  
Dynamic Assay ◽  
Urine Specimens

Abstract Background: Immunoassay-based screening for amphetamines has a variable positive predictive value (PPV) for detecting amphetamine abuse. The lack of immunoassay specificity necessitates confirmatory testing by gas chromatography–mass spectrometry (GC/MS), but the technical complexity and expense of GC/MS limit its availability. Physicians may make decisions regarding patient disposition based on unverified results. In this study we assessed the utility of using dose–response properties to distinguish urine samples containing amphetamines from samples containing cross-immunoreactive species. Methods: Urine was supplemented with known concentrations of amphetamine, methamphetamine, methylenedioxymethamphetamine (MDMA), or pseudoephedrine. Using a series of dilutions, we determined the maximum change in rate over the fractional change in concentration for each compound in the Emit® II amphetamine/methamphetamine immunoassay. Patient urine samples that screened positive for amphetamines were diluted 1:1, 1:10, and 1:20, and maximum slope estimates within the dynamic assay range were determined. An optimal slope cutoff that differentiated samples containing (meth)amphetamine from those containing cross-reacting species was determined by ROC analysis. Results: The slope of the dose response was largest for amphetamine and methamphetamine, followed by MDMA and pseudoephedrine. The optimum slope cutoff for identifying patient specimens containing (meth)amphetamine was 320 (sensitivity, 96%; specificity, 90%; PPV, 92%). High concentrations of less reactive compounds may mask low concentrations of amphetamines. Conclusions: Use of the slope of the dose–response relationship in patient urine specimens can enhance the PPV of presumptive positive immunoassay results but does not exclude the presence of low amphetamine concentrations in samples containing high concentrations of cross-reactive species.

Sign in / Sign up

Export Citation Format

Share Document