Toxicity and disruption of quorum sensing in Aliivibrio fisheri by environmental chemicals: Impacts of selected contaminants and microplastics

The purpose of this study was to examine the effects of dissolved and particulate compounds on quorum sensing in the marine luminescent bacterium Aliivibrio fisheri. Bacteria were exposed to increasing concentrations of CuSO4 (Cu2+), gadolinium chloride (Gd3+), 20-nm silver nanoparticles (nanoAg) and 1-3 μm microplastic polyethylene beads for 250 min. During this period, luminescence measurements were taken at 5-min intervals. Toxicity was first examined by measuring luminescence output at 5-min and 30-min incubation time. Based on the effective concentration that decreases luminescence by 20% (EC20), the compounds were toxic at the following concentrations in decreasing toxicity: Cu2+ (3.2 mg/L) < nanoAg (3.4 mg/L, reported) < Gd3+ (34 mg/L) < microplastics (2.6 g/L). The data revealed that luminescence changed non-linearly over time. In control bacteria, luminescence changed at eight specific major frequencies between 0.04 and 0.27 cycle/min after Fourier transformation of time-dependent luminescence data. The addition of dissolved Cu2+ and Gd3+ eliminated the amplitude changes at these frequencies in a concentration-dependent manner, indicating loss of quorum sensing between bacteria at concentrations below EC20. In the presence of nanoAg and microplastic beads, the decreases in amplitudes were modest but compressed the luminescence profiles, with shorter frequencies appearing at concentrations well below EC20. Thus, loss of communication between bacteria occurs at non-toxic concentrations. In addition, with exposure to a mixture of the above compounds at concentrations that do not produce effects for Gd3+, nanoAg and microplastics, Cu2+ toxicity was significantly enhanced, suggesting synergy. This study revealed for the first time that small microplastic particles and nanoparticles can disrupt quorum sensing in marine bacteria.

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Brassinolide Enhances the Level of Brassinosteroids, Protein, Pigments, and Monosaccharides in Wolffia arrhiza Treated with Brassinazole

Plants ◽

10.3390/plants10071311 ◽

2021 ◽

Vol 10 (7) ◽

pp. 1311

Author(s):

Magdalena Chmur ◽

Andrzej Bajguz

Keyword(s):

Plant Growth ◽

Growth And Development ◽

Inhibitory Effect ◽

Dependent Manner ◽

Plant Growth And Development ◽

Concentration Dependent Manner ◽

Spectrophotometric Methods ◽

Synthetic Inhibitor ◽

Wolffia Arrhiza ◽

First Time

Brassinolide (BL) represents brassinosteroids (BRs)—a group of phytohormones that are essential for plant growth and development. Brassinazole (Brz) is as a synthetic inhibitor of BRs’ biosynthesis. In the present study, the responses of Wolffia arrhiza to the treatment with BL, Brz, and the combination of BL with Brz were analyzed. The analysis of BRs and Brz was performed using LC-MS/MS. The photosynthetic pigments (chlorophylls, carotenes, and xanthophylls) levels were determined using HPLC, but protein and monosaccharides level using spectrophotometric methods. The obtained results indicated that BL and Brz influence W. arrhiza cultures in a concentration-dependent manner. The most stimulatory effects on the growth, level of BRs (BL, 24-epibrassinolide, 28-homobrassinolide, 28-norbrassinolide, catasterone, castasterone, 24-epicastasterone, typhasterol, and 6-deoxytyphasterol), and the content of pigments, protein, and monosaccharides, were observed in plants treated with 0.1 µM BL. Whereas the application of 1 µM and 10 µM Brz caused a significant decrease in duckweed weight and level of targeted compounds. Application of BL caused the mitigation of the Brz inhibitory effect and enhanced the BR level in duckweed treated with Brz. The level of BRs was reported for the first time in duckweed treated with BL and/or Brz.

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Cytotoxic Effects of Ferula Latisecta on Human Glioma U87 Cells

Drug Research ◽

10.1055/a-0986-6543 ◽

2019 ◽

Vol 69 (12) ◽

pp. 665-670 ◽

Cited By ~ 6

Author(s):

Mohammad Jalili-Nik ◽

Hamed Sabri ◽

Ehsan Zamiri ◽

Mohammad Soukhtanloo ◽

Mostafa Karimi Roshan ◽

...

Keyword(s):

Enzymatic Activity ◽

Gelatin Zymography ◽

Annexin V ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Ic50 Values ◽

Induced Apoptosis ◽

Natural Herb ◽

First Time ◽

U87 Cells

AbstractGlioblastoma multiforme (GBM) is the fatal type of astrocytic tumors with a survival rate of 12 months. The present study, for the first time, evaluated the cytotoxic impacts of Ferula latisecta (F. latisecta) hydroalcoholic extract on U87 GBM cell line. The MTT assay measured the cellular toxicity following 24- and 48 h treatment with various doses of F. latisecta (0–800 μg/mL). Apoptosis was evaluated by an Annexin V/propidium iodide (PI) staining 24 h after treatment by F. latisecta. Moreover, to determine the cellular metastasis of U87 cells, we used a gelatin zymography assay (matrix metalloproteinase [MMP]-2/-9 enzymatic activity). The outcomes showed that F. latisecta mitigated the viability of U87 cells in a concentration- and time-dependent manner with IC50 values of 145.3 and 192.3 μg/mL obtained for 24- and 48 h treatments, respectively. F. latisecta induced apoptosis in a concentration-dependent manner after 24 h. Also, MMP-9 activity was significantly decreased following 24 h after treatment concentration-dependently with no change in MMP-2 enzymatic activity. This study showed that F. latisecta induced cytotoxicity and apoptosis, and mitigated metastasis of U87 GBM cells. Hence, F. latisecta could be beneficial as a promising natural herb against GBM after further studies.

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Small Molecule Constituents of Periplaneta americana and Their IL-6 Inhibitory Activities

Natural Product Communications ◽

10.1177/1934578x211033180 ◽

2021 ◽

Vol 16 (9) ◽

pp. 1934578X2110331

Author(s):

Hua-Sheng Zhang ◽

Yong-Ming Yan ◽

Dai-Wei Wang ◽

Qing Lv ◽

Yong-Xian Cheng ◽

...

Keyword(s):

High Performance Liquid Chromatography ◽

High Performance ◽

Periplaneta Americana ◽

Ethanol Extract ◽

Biological Evaluation ◽

Dependent Manner ◽

Chemical Methods ◽

Concentration Dependent Manner ◽

Inhibitory Activities ◽

First Time

Two new glycosides, periplanosides A (1) and B (2), 3 compounds reported from a natural source for the first time (3 − 5), and 6 known compounds 6 − 11 were isolated from the ethanol extract of Periplaneta americana (Linnaeus). Their structures, including absolute configurations, were unambiguously identified by comprehensive spectroscopic and chemical methods. Compound 3 is a racemate whose enantiomers were purified by chiral high-performance liquid chromatography . The biological evaluation results showed that compound 7 (0 − 20 μM) did not affect the viability of RAW264.7 cells and could effectively inhibit the production of interleukin-6 stimulated by lipopolysaccharide in a concentration-dependent manner, indicating the potential to develop novel agents against inflammation-related diseases.

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An Alanine-Rich Peptide Attenuates Quorum Sensing-Regulated Virulence and Biofilm Formation in Staphylococcus aureus

Journal of AOAC International ◽

10.5740/jaoacint.18-0251 ◽

2019 ◽

Vol 102 (4) ◽

pp. 1228-1234 ◽

Cited By ~ 1

Author(s):

Raid Al Akeel ◽

Ayesha Mateen ◽

Rabbani Syed

Keyword(s):

Gene Expression ◽

Staphylococcus Aureus ◽

Quorum Sensing ◽

Biofilm Formation ◽

Bacterial Attachment ◽

The Body ◽

Dependent Manner ◽

Virulence Determinants ◽

Microarray Gene Expression ◽

Concentration Dependent Manner

Abstract Background: Alanine-rich proteins/peptides (ARP), with bioactivity of up to 20 amino acid residues, can be observed by the body easily during gastrointestinal digestion. Objective: Populus trichocarpa extract’s capability to attenuate quorum sensing-regulated virulence and biofilm formation in Staphylococcus aureus is described. Methods: PT13, an ARP obtained from P. trichocarpa, was tested for its activity against S. aureus using the broth microdilution test; a crystal-violet biofilm assay was performed under a scanning electron microscope. The production of various virulence factors was estimated with PT13 treatment. Microarray gene expression profiling of PT13-treated S. aureus was conducted and compared with an untreated control. Exopolysaccharides (EPS) was estimated to observe the PT13 inhibition activity. Results: PT13 was antimicrobial toward S. aureus at different concentrations and showed a similar growth rate in the presence and absence of PT13 at concentrations ≤8 μg/mL. Biofilm production was interrupted even at low concentrations, and biofilm-related genes were down-regulated when exposed to PT13. The genes encoding cell adhesion and bacterial attachment protein were the major genes suppressed by PT13. In addition, hemolysins, clumping activity, and EPS production of S. aureus decreased after treatment in a concentration-dependent manner. Conclusions: A long-chain PT13 with effective actions that, even at low concentration levels, not only regulated the gene expression in the producer organism but also blocked the virulence gene expression in this Gram-positive human pathogen is described. Highlights: We identified a PT13 as a potential antivirulence agent that regulated production of bacterial virulence determinants (e.g., toxins, enzymes and biofilm), downwards and it may be a promising anti-virulence agent to be further developed as an anti-infective agent.

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Essential Oils of Aromatic Plants with Antibacterial, Anti-Biofilm and Anti-Quorum Sensing Activities against Pathogenic Bacteria

Antibiotics ◽

10.3390/antibiotics9040147 ◽

2020 ◽

Vol 9 (4) ◽

pp. 147 ◽

Cited By ~ 5

Author(s):

Marlon Cáceres ◽

William Hidalgo ◽

Elena Stashenko ◽

Rodrigo Torres ◽

Claudia Ortiz

Keyword(s):

Escherichia Coli ◽

Antimicrobial Activity ◽

Quorum Sensing ◽

Essential Oils ◽

Pathogenic Bacteria ◽

Bacterial Resistance ◽

Thymus Vulgaris ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Biofilm Inhibition

Both the ability of bacteria to form biofilms and communicate through quorum sensing allows them to develop different survival or virulence traits that lead to increased bacterial resistance against conventional antibiotic therapy. Here, seventeen essential oils (EOs) were investigated for the antimicrobial, antibiofilm, and anti-quorum sensing activities on Escherichia. coli O157:H7, Escherichia coli O33, and Staphylococcus epidermidis ATCC 12228. All essential oils were isolated from plant material by using hydrodistillation and analyzed by GC-MS. The antimicrobial activity was performed by using the microdilution technique. Subinhibitory concentrations of each EO were assayed for biofilm inhibition in both bacterial strains. Quantification of violacein in Chromobacterium violaceum CV026 was performed for the anti-quorum sensing activity. The cytotoxicity activity of the EOs was evaluated on Vero cell line by using MTT method. Thymol-carvacrol-chemotype (I and II) oils from Lippia origanoides and Thymus vulgaris oil exhibited the higher antimicrobial activity with MIC values of 0.37–0.75 mg/mL. In addition, these EOs strongly inhibited the biofilm formation and violacein (QS) production in a concentration-dependent manner, highlighting thymol-carvacrol-chemotype (II) oil as the best candidate for further studies in antibiotic design and development against bacterial resistance.

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Using a Multi-Stage hESC Model to Characterize BDE-47 Toxicity During Neurogenesis

Toxicological Sciences ◽

10.1093/toxsci/kfz136 ◽

2019 ◽

Vol 171 (1) ◽

pp. 221-234 ◽

Cited By ~ 3

Author(s):

Hao Chen ◽

Helia Seifikar ◽

Nicholas Larocque ◽

Yvonne Kim ◽

Ibrahim Khatib ◽

...

Keyword(s):

Neural Development ◽

Polybrominated Diphenyl Ethers ◽

Neuronal Development ◽

Embryonic Stem ◽

Cellular Level ◽

Environmental Chemicals ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Neurodevelopmental Toxicity

Abstract Although the ramifications associated with polybrominated diphenyl ethers (PBDEs) exposures during human pregnancy have yet to be determined, increasing evidence in humans and animal models suggests that these compounds cause neurodevelopmental toxicity. Human embryonic stem cells (hESCs) models can be used to study the effects of environmental chemicals throughout the successive stages of neuronal development. Here, using a hESC differentiation model, we investigated the effects of common PBDE congeners (BDE-47 or -99) on the successive stages of early neuronal development. First, we determined the points of vulnerability to PBDEs across 4 stages of in vitro neural development by using assays to assess for cytotoxicity. Differentiated neural progenitors were identified to be more sensitive to PBDEs than their less differentiated counterparts. In follow-up investigations, we observed BDE-47 to inhibit functional processes critical for neurogenesis (eg, proliferation, expansion) in hESC-derived neural precursor cells (NPCs) at sub-lethal concentrations. Finally, to determine the mechanism(s) underlying PBDE-toxicity, we conducted global transcriptomic and methylomic analyses of BDE-47. We identified 589 genes to be differentially expressed due to BDE-47 exposure, including molecules involved in oxidative stress mediation, cell cycle, hormone signaling, steroid metabolism, and neurodevelopmental pathways. In parallel analyses, we identified a broad significant increase in CpG methylation. In summary our results suggest, on a cellular level, PBDEs induce human neurodevelopmental toxicity in a concentration-dependent manner and sensitivity to these compounds is dependent on the developmental stage of exposure. Proposed mRNA and methylomic perturbations may underlie toxicity in early embryonic neuronal populations.

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Farnesol and Tyrosol: Secondary Metabolites with a Crucial quorum-sensing Role in Candida Biofilm Development

Genes ◽

10.3390/genes11040444 ◽

2020 ◽

Vol 11 (4) ◽

pp. 444 ◽

Cited By ~ 4

Author(s):

Célia F. Rodrigues ◽

Lucia Černáková

Keyword(s):

Quorum Sensing ◽

Secondary Metabolites ◽

Regulation Of Gene Expression ◽

Main Role ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Microbial Infections ◽

Bacteria And Fungi ◽

Spherical Cells ◽

Biofilm Development

When living in biological and interactive communities, microorganisms use quorum-sensing mechanisms for their communication. According to cell density, bacteria and fungi can produce signaling molecules (e.g., secondary metabolites), which participate, for example, in the regulation of gene expression and coordination of collective behavior in their natural niche. The existence of these secondary metabolites plays a main role in competence, colonization of host tissues and surfaces, morphogenesis, and biofilm development. Therefore, for the design of new antibacterials or antifungals and understanding on how these mechanisms occur, to inhibit the secretion of quorum-sensing (e.g., farnesol and tyrosol) molecules leading the progress of microbial infections seems to be an interesting option. In yeasts, farnesol has a main role in the morphological transition, inhibiting hyphae production in a concentration-dependent manner, while tyrosol has a contrary function, stimulating transition from spherical cells to germ tube form. It is beyond doubt that secretion of both molecules by fungi has not been fully described, but specific meaning for their existence has been found. This brief review summarizes the important function of these two compounds as signaling chemicals participating mainly in Candida morphogenesis and regulatory mechanisms.

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Identification of Major α-Glucosidase Inhibitors from Stem Bark of Panamanian Mangrove Plant Pelliciera rhizophorae

Natural Product Communications ◽

10.1177/1934578x1901400105 ◽

2019 ◽

Vol 14 (1) ◽

pp. 1934578X1901400

Author(s):

Lilia Cherigo ◽

Sergio Martínez-Luis

Keyword(s):

Stem Bark ◽

Spectrometric Analysis ◽

Dependent Manner ◽

Mangrove Plant ◽

Concentration Dependent Manner ◽

Pentacyclic Triterpenes ◽

Aerial Parts ◽

Glucosidase Inhibitors ◽

Pelliciera Rhizophorae ◽

First Time

In our continuous search for α-glucosidase inhibitors, three active pentacyclic triterpenes were isolated from stem bark samples of the Panamanian mangrove Pelliciera rhizophorae Triana & Planchon. These compounds were identified by both spectroscopic and spectrometric analysis. Of the isolated compounds, only betulinic acid has been previously isolated from P. rhizophorae leaves while both betulin (IC50 2.09 μM) and lupeol (IC50 0.58 μM) were isolated from this plant for the first time. All three pentacyclic triterpenes inhibited the α-glucosidase enzyme in a concentration-dependent manner, and their inhibitory activity was higher than that of the antidiabetic drug acarbose (IC50 241.6 μM). Kinetic analysis established that betulin and lupeol acted as competitive inhibitors. Finally, docking analysis suggested that all three triterpenes bind at the same site as acarbose does in the human intestinal α-glucosidase (PDB: 3TOP). This work contributes further evidence similar to previous studies that point out that the aerial parts of P. rhizophorae might be potential agents in controlling hyperglycemia in diabetic persons.

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Cholecystokinin Octapeptide Increases Spontaneous Glutamatergic Synaptic Transmission to Neurons of the Nucleus Tractus Solitarius Centralis

Journal of Neurophysiology ◽

10.1152/jn.00351.2005 ◽

2005 ◽

Vol 94 (4) ◽

pp. 2763-2771 ◽

Cited By ~ 40

Author(s):

V. Baptista ◽

Z. L. Zheng ◽

F. H. Coleman ◽

R. C. Rogers ◽

R. A. Travagli

Keyword(s):

Receptor Antagonist ◽

Nucleus Tractus Solitarius ◽

Dependent Manner ◽

Excitatory Effect ◽

Concentration Dependent Manner ◽

Whole Cell Patch Clamp ◽

Glutamatergic Synaptic Transmission ◽

Immunohistochemical Techniques ◽

20 Nm ◽

Brain Stem Slices

Cholecystokinin (CCK) is released from enteroendocrine cells after ingestion of nutrients and induces multiple effects along the gastrointestinal tract, including gastric relaxation and short-term satiety. We used whole cell patch-clamp and immunohistochemical techniques in rat brain stem slices to characterize the effects of CCK. In 45% of the neurons of nucleus tractus solitarius subnucleus centralis (cNTS), perfusion with the sulfated form of CCK (CCK-8s) increased the frequency of spontaneous excitatory currents (sEPSCs) in a concentration-dependent manner (1–300 nM). The threshold for the CCK-8s excitatory effect was 1 nM, the EC50 was 20 nM, and Emax was 100 nM. The excitatory effects of CCK-8s were still present when the slices were preincubated with tetrodotoxin or bicuculline or when the recordings were conducted with Cs+ electrodes. Pretreatment with the CCK-A receptor antagonist, lorglumide (1 μM), antagonized the effects of CCK-8s, whereas perfusion with the CCK-B preferring agonist CCK-8 nonsulfated (CCK-ns, 1 μM) did not affect the frequency of sEPSCs. Similarly, pretreatment with the CCK-B receptor antagonist, triglumide (1 μM), did not prevent the actions of CCK-8s. Although the majority (i.e., 76%) of CCK-8s unresponsive cNTS neurons had a bipolar somata shape and were TH-IR negative, no differences were found in either the morphological or the neurochemical phenotype of cNTS neurons responsive to CCK-8s. Our results suggest that the excitatory effects of CCK-8s on terminals impinging on a subpopulation of cNTS neurons are mediated by CCK-A receptors; these responsive neurons, however, do not have morphological or neurochemical characteristics that automatically distinguish them from nonresponsive neurons.

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A C21-Steroidal Glycoside from Cynanchum atratum Attenuates Concanavalin A-Induced Liver Injury in Mice

Molecules ◽

10.3390/molecules24061087 ◽

2019 ◽

Vol 24 (6) ◽

pp. 1087 ◽

Cited By ~ 2

Author(s):

Jian Yang ◽

Bin Wang ◽

Chao-feng Zhang ◽

Xiang-hong Xu ◽

Mian Zhang

Keyword(s):

T Lymphocytes ◽

Concanavalin A ◽

Underlying Mechanism ◽

Dependent Manner ◽

Histopathological Changes ◽

Con A ◽

Concentration Dependent Manner ◽

Steroidal Glycoside ◽

First Time

Cynatratoside A (CyA) is a C21 Steroidal glycoside with pregnane skeleton isolated from the root of Cynanchum atratum Bunge (Asclepiadaceae). This study aimed to investigate the effects of CyA on concanavalin A (Con A)-induced autoimmune hepatitis (AIH) and the underlying mechanism. CyA was orally administered to mice at 10 and 40 mg/kg 8 h before and 1 h after Con A treatment. The effects of CyA on Con A-induced spleen and liver in mice were assessed via histopathological changes, T lymphocyte amounts and the expressions of IL-1β and ICAM-1. Con A-induced L-02 hepatocytes were used to evaluate whether CyA (0.1–10 μM) can directly protect hepatocytes from cytotoxicity and the possible mechanism. The results revealed that CyA treatment could significantly improve the histopathological changes of spleen and liver, reduce the proliferation of splenic T lymphocytes, and decrease the expressions of IL-1β and ICAM-1 in liver. The experiment in vitro showed that CyA inhibited Con A-induced hepatotoxicity in a concentration-dependent manner. CyA (10 μM) significantly increased/decreased the expression of Bcl-2/Bax and reduced the levels of cleaved caspases-9 and -3. Our study demonstrated for the first time that CyA has a significant protective effect on Con A-induced AIH by inhibiting the activation and adhesion of T lymphocytes and blocking hepatocyte apoptosis.

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