scholarly journals Entomotoxic Activity of the Extracts from the Fungus, Alternaria tenuissima and Its Major Metabolite, Tenuazonic Acid

Author(s):  
Dilara Salimova ◽  
Anna Dalinova ◽  
Vsevolod Dubovik ◽  
Igor Sendersky ◽  
Elena Stepanycheva ◽  
...  

Study of fungal antibiotics in their competitive interactions with arthropods may lead to development novel biorational insecticides. Extracts of Alternaria tenuissima MFP253011 obtained by various methods showed a wide range of biological activity, including entomotoxic properties. Analysis of their composition and bioactivity allowed to reveal several known mycotoxins and unidentified compounds that may be involved in entomotoxic activity of the extracts. Among them, tenuazonic acid (TeA), which was the major component of the A. tenuissima extracts, was found the most likely to have larvicidal activity against Galleria mellonella. In the intrahaemocoel injection bioassay, TeA was toxic to G. mellonella and of Zophobas morio with LT50 6 and 2 days, respectively, at the level of 50 µg/larva. Administered orally, TeA inhibited growth of G. mellonella larvae and caused mortality of Acheta domesticus imagines (LT50 7 days) at a concentration of 250 µg/g of feed. TeA showed weak contact-intestinal activity against the two phytophages, Tetranychus urticae and Schizaphis graminum, causing the 12 and 40% of mortality at a concentration of 1 mg/mL. TeA was cytotoxic to Sf9 cell line (IC50 25 µg/mL). Thus, model insect G. mellonella and cell line Sf9 could be used for a further toxicological characterization of TeA.

2021 ◽  
Vol 7 (9) ◽  
pp. 774
Author(s):  
Dilara Salimova ◽  
Anna Dalinova ◽  
Vsevolod Dubovik ◽  
Igor Senderskiy ◽  
Elena Stepanycheva ◽  
...  

The study of fungal antibiotics in their competitive interactions with arthropods may lead to the development of novel biorational insecticides. Extracts of Alternaria tenuissima MFP253011 obtained using various methods showed a wide range of biological activities, including entomotoxic properties. Analysis of their composition and bioactivity allowed us to reveal several known mycotoxins and unidentified compounds that may be involved in the entomotoxic activity of the extracts. Among them, tenuazonic acid (TeA), which was the major component of the A. tenuissima extracts, was found the most likely to have larvicidal activity against Galleria mellonella. In the intrahaemocoel injection bioassay, TeA was toxic to G. mellonella and of Zophobas morio with an LT50 of 6 and 2 days, respectively, at the level of 50 µg/larva. Administered orally, TeA inhibited the growth of G. mellonella larvae and caused mortality of Acheta domesticus adults (LT50 7 days) at a concentration of 250 µg/g of feed. TeA showed weak contact intestinal activity against the two phytophages, Tetranychus urticae and Schizaphis graminum, causing 15% and 27% mortality at a concentration of 1 mg/mL, respectively. TeA was cytotoxic to the Sf9 cell line (IC50 25 µg/mL). Thus, model insects such as G. mellonella could be used for further toxicological characterization of TeA.


Parasitology ◽  
2020 ◽  
Vol 147 (13) ◽  
pp. 1524-1531
Author(s):  
Cristian Camilo Galindo ◽  
Carlos Arturo Clavijo-Ramírez

AbstractMonocytes and macrophages are involved in a wide range of biological processes and parasitic diseases. The characterization of the molecular mechanisms governing such processes usually requires precise control of the expression of genes of interest. We implemented a tetracycline-controlled gene expression system in the U937 cell line, one of the most used in vitro models for the research of human monocytes and macrophages. Here we characterized U937-derived cell lines in terms of phenotypic (morphology and marker expression) and functional (capacity for phagocytosis and for Leishmania parasite hosting) changes induced by phorbol-12-myristate-13-acetate (PMA). Finally, we provide evidence of tetracycline-inducible and reversible Lamin-A gene silencing of the PMA-differentiated U937-derived cells.


2017 ◽  
Vol 85 (9) ◽  
Author(s):  
Grant Mills ◽  
Amy Dumigan ◽  
Timothy Kidd ◽  
Laura Hobley ◽  
José A. Bengoechea

ABSTRACT Klebsiella pneumoniae causes a wide range of infections, from urinary tract infections to pneumonia. The lipopolysaccharide is a virulence factor of this pathogen, although there are gaps in our understanding of its biosynthesis. Here we report on the characterization of K. pneumoniae lpxL, which encodes one of the enzymes responsible for the late secondary acylation of immature lipid A molecules. Analysis of the available K. pneumoniae genomes revealed that this pathogen's genome encodes two orthologues of Escherichia coli LpxL. Using genetic methods and mass spectrometry, we demonstrate that LpxL1 catalyzes the addition of laureate and LpxL2 catalyzes the addition of myristate. Both enzymes acylated E. coli lipid A, whereas only LpxL2 mediated K. pneumoniae lipid A acylation. We show that LpxL1 is negatively regulated by the two-component system PhoPQ. The lipid A produced by the lpxL2 mutant lacked the 2-hydroxymyristate, palmitate, and 4-aminoarabinose decorations found in the lipid A synthesized by the wild type. The lack of 2-hydroxymyristate was expected since LpxO modifies the myristate transferred by LpxL2 to the lipid A. The absence of the other two decorations is most likely caused by the downregulation of phoPQ and pmrAB expression. LpxL2-dependent lipid A acylation protects Klebsiella from polymyxins, mediates resistance to phagocytosis, limits the activation of inflammatory responses by macrophages, and is required for pathogen survival in the wax moth (Galleria mellonella). Our findings indicate that the LpxL2 contribution to virulence is dependent on LpxO-mediated hydroxylation of the LpxL2-transferred myristate. Our studies suggest that LpxL2 might be a candidate target in the development of anti-K. pneumoniae drugs.


2020 ◽  
Vol 16 (4) ◽  
pp. 419-431
Author(s):  
Kishore K. Valluri ◽  
Tejeswara R. Allaka ◽  
IV Kasi Viswanath ◽  
Nagaraju PVVS

Background: Many pyrazole piperazine derivatives are known to exhibit a wide range, thus being attractive for the drug design and synthesis of interesting class of widely studied heterocyclic compounds. It is therefore necessary to devote continuing effort for the identification and development of New Chemical Entities (NCEs) as potential antibacterial and anticancer agents to address serious health problems. Methods: A series of new compounds containing pyrazole ring linked to a piperazine hydrochloride moiety were synthesized and screened for their antibacterial activity, cytotoxicity of novel scaffolds are described by variation in therapeutic effects of parent molecule. The structure variants were characterized by using a blend of spectroscopic 1H NMR, 13C NMR, IR, Mass and chromatographic techniques. Results: When tested for in vitro antibacterial and anticancer activities, several of these compounds showed good activities. The target compounds 9b, 9a and 9e exhibited a high degree of anticancer activity against human colon cancer cell line Caco-2 and human breast cancer cell line MDAMB231. Further, 9a, 9b, 9d, and 9h showed better activity towards four medically relevant organisms; Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Klebsiella Species compared to CPF. In the present investigation, cheminfomatics tools Molinspiration, 2003 and MolSoft, 2007 for the prediction of insilico molecular properties and drug likeness for the target compounds 9a-h was evaluated and positive results were observed. Conclusion: Our study revealed that the molecular framework presented here could be a useful template for the identification of novel small molecules as promising antibacterial/ anticancer agents.


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