scholarly journals TmPGRP-SA regulates Antimicrobial Response to Bacteria and Fungi in the Fat Body and Gut of Tenebrio molitor

2020 ◽  
Vol 21 (6) ◽  
pp. 2113 ◽  
Author(s):  
Maryam Keshavarz ◽  
Yong Hun Jo ◽  
Tariku Tesfaye Edosa ◽  
Young Min Bae ◽  
Yeon Soo Han

Antimicrobial immune response is mediated by a signal-transducing sensor, peptidoglycan recognition protein-SA (PGRP-SA), that can recognize non-self molecules. Although several studies have focused on the involvement of Drosophila PGRP-SA in antimicrobial peptide (AMP) expression in response to infections, studies on its role in Tenebrio molitor are lacking. Here, we present a functional analysis of T. molitor PGRP-SA (TmPGRP-SA). In the absence of microbes, TmPGRP-SA was highly expressed in the late-larval fat body, followed by hemocytes, and gut. Interestingly, following Escherichia coli, Staphylococcus aureus, and Candida albicans infections, the mRNA level of TmPGRP-SA was significantly upregulated in both the fat body and gut. TmPGRP-SA silencing had a significant effect on the mortality rates for all the microbes tested. Moreover, TmPGRP-SA is required for regulating the expression of eight AMP genes namely TmTenecin-1, -2, and -4; TmDefensin-1 and -2; TmColeoptericin-1; and TmAttacin-1b and -2 in the fat body in response to E. coli and S. aureus infections. TmPGRP-SA is essential for the transcription of TmTenecin-2, -4; TmDefensin-2; TmColeoptericin-1, -2; and TmAttacin-1a, -1b, and -2 in the gut upon E. coli and C. albicans infections. However, TmPGRP-SA does not regulate AMP expression in the hemocytes. Additionally, TmDorsal isoform X2, a downstream Toll transcription factor, was downregulated in TmPGRP-SA-silenced larval fat body following E. coli and S. aureus challenges, and in the gut following E. coli and C. albicans challenges.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chun-Kai Yang ◽  
Des R. Kashyap ◽  
Dominik A. Kowalczyk ◽  
David Z. Rudner ◽  
Xindan Wang ◽  
...  

AbstractMammalian peptidoglycan recognition proteins (PGRPs or PGLYRPs) kill bacteria through induction of synergistic oxidative, thiol, and metal stress. Tn-seq screening of Bacillus subtilis transposon insertion library revealed that mutants in the shikimate pathway of chorismate synthesis had high survival following PGLYRP4 treatment. Deletion mutants for these genes had decreased amounts of menaquinone (MK), increased resistance to killing, and attenuated depletion of thiols following PGLYRP4 treatment. These effects were reversed by MK or reproduced by inhibiting MK synthesis. Deletion of cytochrome aa3-600 or NADH dehydrogenase (NDH) genes also increased B. subtilis resistance to PGLYRP4-induced killing and attenuated thiol depletion. PGLYRP4 treatment also inhibited B. subtilis respiration. Similarly in Escherichia coli, deletion of ubiquinone (UQ) synthesis, formate dehydrogenases (FDH), NDH-1, or cytochrome bd-I genes attenuated PGLYRP4-induced thiol depletion. PGLYRP4-induced low level of cytoplasmic membrane depolarization in B. subtilis and E. coli was likely not responsible for thiol depletion. Thus, our results show that the respiratory electron transport chain components, cytochrome aa3-600, MK, and NDH in B. subtilis, and cytochrome bd-I, UQ, FDH-O, and NDH-1 in E. coli, are required for both PGLYRP4-induced killing and thiol depletion and indicate conservation of the PGLYRP4-induced thiol depletion and killing mechanisms in Gram-positive and Gram-negative bacteria.


2020 ◽  
Vol 13 (3) ◽  
pp. 46
Author(s):  
Tiago Fonseca Silva ◽  
José Robson Neves Cavalcanti Filho ◽  
Mariana Mirelle Lima Barreto Fonsêca ◽  
Natalia Medeiros dos Santos ◽  
Ana Carolina Barbosa da Silva ◽  
...  

The relevance of oxidative stress in the pathogenesis of several diseases (including inflammatory disorders) has traditionally led to the search for new sources of antioxidant compounds. In this work, we report the selection of fractions with high antioxidant action from B. tetraphylla (BT) leaf extracts. In vitro methods (DPPH and ABTS assays; determination of phenolic and flavonoid contents) were used to select products derived from B. tetraphylla with high antioxidant action. Then, the samples with the highest potentials were evaluated in a model of injury based on the inoculation of a lethal dose of heat-inactivated Escherichia coli in Tenebrio molitor larvae. Due to its higher antioxidant properties, the methanolic extract (BTME) was chosen to be fractionated using Sephadex LH-20 column-based chromatography. Two fractions from BTME (BTFC and BTFD) were the most active fractions. Pre-treatment with these fractions protected larvae of T. molitor from the stress induced by inoculation of heat-inactivated E. coli. Similarly, BTFC and BTFD increased the lifespan of larvae infected with a lethal dose of enteroaggregative E. coli 042. NMR data indicated the presence of aliphatic compounds (terpenes, fatty acids, carbohydrates) and aromatic compounds (phenolic compounds). These findings suggested that products derived from B. tetraphylla leaves are promising candidates for the development of antioxidant and anti-infective agents able to treat oxidative-related dysfunctions.


2020 ◽  
Vol 21 (17) ◽  
pp. 6090
Author(s):  
Tariku Tesfaye Edosa ◽  
Yong Hun Jo ◽  
Maryam Keshavarz ◽  
In Seon Kim ◽  
Yeon Soo Han

Biosurfactant immunomodulatory activities in mammals, nematodes, and plants have been investigated. However, the immune activation property of biosurfactants in insects has not been reported. Therefore, here, we studied the defense response triggered by lipopeptides (fengycin and iturin A), glycolipids (rhamnolipid), and cyclic polypeptides (bacitracin) in the coleopteran insect, mealworm Tenebrio molitor. The in vitro antimicrobial activities against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria and fungi (Candida albicans) were assessed by mixing these pathogens with the hemolymph of biosurfactant-immune-activated larvae. E. coli growth was remarkably inhibited by this hemolymph. The antimicrobial peptide (AMP) induction results also revealed that all biosurfactants tested induced several AMPs, exclusively in hemocytes. The survivability analysis of T. molitor larvae challenged by E. coli (106 CFU/µL) at 24 h post biosurfactant-immune activation showed that fengycin, iturin A, and rhamnopid significantly increased survivability against E. coli. Biosurfactant-induced TmSpatzles activation was also monitored, and the results showed that TmSpz3 and TmSpz-like were upregulated in the hemocytes of iturin A-injected larvae, while TmSpz4 and TmSpz6 were upregulated in the fat bodies of the fengycin-, iturin A-, and rhamnolipid-injected larvae. Overall, these results suggest that lipopeptide and glycolipid biosurfactants induce the expression of AMPs in T. molitor via the activation of spätzle genes, thereby increasing the survivability of T. molitor against E. coli.


2015 ◽  
Vol 8 (1) ◽  
pp. 67-80 ◽  
Author(s):  
Denis Costechareyre ◽  
Florence Capo ◽  
Alexandre Fabre ◽  
Delphine Chaduli ◽  
Christine Kellenberger ◽  
...  

In Drosophila, peptidoglycan (PGN) is detected by PGN recognition proteins (PGRPs) that act as pattern recognition receptors. Some PGRPs such as PGRP-LB or PGRP-SCs are able to cleave PGN, therefore reducing the amount of immune elicitors and dampening immune deficiency (IMD) pathway activation. The precise role of PGRP-SC is less well defined because the PGRP-SC genes (PGRP-SC1a, PGRP-SC1b and PGRP-SC2) lie very close on the chromosome and have been studied using a deletion encompassing the three genes. By generating PGRP-SC-specific mutants, we reevaluated the roles of PGRP-LB, PGRP-SC1 and PGRP-SC2, respectively, during immune responses. We showed that these genes are expressed in different gut domains and that they follow distinct transcriptional regulation. Loss-of-function mutant analysis indicates that PGRP-LB is playing a major role in IMD pathway activation and bacterial load regulation in the gut, although PGRP-SCs are expressed at high levels in this organ. We also demonstrated that PGRP-SC2 is the main negative regulator of IMD pathway activation in the fat body. Accordingly, we showed that mutants for either PGRP-LB or PGRP-SC2 displayed a distinct susceptibility to bacteria depending on the infection route. Lastly, we demonstrated that PGRP-SC1 and PGRP-SC2 are required in vivo for full Toll pathway activation by Gram-positive bacteria.


2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Lin Zhang ◽  
Jienan Chen ◽  
Wenji Yu ◽  
Qingfeng Zhao ◽  
Jin Liu

Nanocomposites of Ag with organic montmorillonite (Ag-OMMT), Ag with montmorillonite (Ag-MMT), and organic montmorillonite (OMMT) were successfully prepared via a one-step solution-intercalated method. Sodium MMT, silver nitrate, and dimethyl octadecyl hydroxy ethyl ammonium nitrate were used as precursors. X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and energy dispersive spectroscopy analyses confirmed that the MMT layers were intercalated, and Ag+ was partly reduced to silver nanoparticles with diameters within 10–20 nm in Ag-OMMT. The decomposition temperature of the organic cations in OMMT and Ag-OMMT increased to 220°C, as revealed by differential scanning calorimetry-thermogravimetric analysis. The antimicrobial activity of the nanocomposites was tested by measuring the minimum inhibitory concentration (MIC) and killing rate. The MICs of Ag-OMMT against Staphylococcus aureus, Escherichia coli, and Candida albicans were 0.313, 2.5, and 0.625 mg/mL, respectively. Because of the presence of quaternary ammonium nitrate, Ag-OMMT has a better MIC against Gram-positive bacteria compared to Gram-negative bacteria and fungi. OMMT did not show antimicrobial activity against Escherichia coli and Candida albicans. In 2 h, 0.0125 mg/mL Ag-OMMT could kill 100% of S. aureus, E. coli, and C. albicans in solution, and Ag-MMT could kill 99.995% of S. aureus, 90.15% of E. coli, and 93.68% of C. albicans. These antimicrobial functional nanocomposites have the potential for application in the area of surface decoration films.


2004 ◽  
Vol 72 (10) ◽  
pp. 6012-6022 ◽  
Author(s):  
Sunil K. Sukumaran ◽  
Suresh K. Selvaraj ◽  
Nemani V. Prasadarao

ABSTRACT Escherichia coli K1 survival in the blood is a critical step for the onset of meningitis in neonates. Therefore, the circulating bacteria are impelled to avoid host defense mechanisms by finding a niche to survive and multiply. Our recent studies have shown that E. coli K1 enters and survives in both monocytes and macrophages in the newborn rat model of meningitis as well as in macrophage cell lines. Here we demonstrate that E. coli K1 not only extends the survival of human and murine infected macrophage cell lines but also renders them resistant to apoptosis induced by staurosporine. Macrophages infected with wild-type E. coli expressing outer membrane protein A (OmpA), but not with OmpA− E. coli, are resistant to DNA fragmentation and phosphatidylserine exposure induced by staurosporine. Infection with OmpA+ E. coli induces the expression of BclXL, an antiapoptotic protein, both at the mRNA level as assessed by gene array analysis and at the protein level as evaluated by immunoblotting. OmpA− E. coli infection of macrophages induced the release of cytochrome c from mitochondria into the cytosol and the activation of caspases 3, 6, and 9, events that were significantly blocked in OmpA+ E. coli-infected macrophages. In addition, OmpA+ E. coli-infected cells were resistant to a decrease in the transmembrane potential of mitochondria induced by staurosporine as measured by the MitoCapture fluorescence technique. Complementation of OmpA− E. coli with a plasmid containing the ompA gene restored the ability of OmpA− E. coli to inhibit the apoptosis of infected macrophages, further demonstrating that E. coli OmpA expression is critical for inducing macrophage survival and thereby finding a safe haven for its growth.


Animals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2118
Author(s):  
Jian Jin ◽  
Yanjie Huang ◽  
Shouyong Sun ◽  
Zhengchang Wu ◽  
Shenglong Wu ◽  
...  

The efficacy and regulatory activity of bactericidal/permeability-increasing protein (BPI) as a mediator of Escherichia coli (E. coli) F18 resistance remains to be defined. In the present study, we evaluated lipopolysaccharide (LPS)-induced changes in BPI gene expression in porcine kidney (PK15) cells in response to E. coli F18 exposure. We additionally generated PK15 cells that overexpressed BPI to assess the impact of this gene on Toll-like receptor 4 (TLR4) signaling and glycosphingolipid biosynthesis-related genes. Through these analyses, we found that BPI expression rose significantly following LPS exposure in response to E. coli F18ac stimulation (p < 0.01). Colony count assays and qPCR analyses revealed that E. coli F18 adherence to PK15 cells was markedly suppressed following BPI overexpression (p < 0.01). BPI overexpression had no significant effect on the mRNA-level expression of genes associated with glycosphingolipid biosynthesis or TLR4 signaling. BPI overexpression suppressed the LPS-induced TLR4 signaling pathway-related expression of proinflammatory cytokines (IFN-α, IFN-β, MIP-1α, MIP-1β and IL-6). Overall, our study serves as an overview of the association between BPI and resistance to E. coli F18 at the cellular level, offering a framework for future investigations of the mechanisms whereby piglets are able to resist E. coli F18 infection.


2005 ◽  
Vol 187 (4) ◽  
pp. 1344-1349 ◽  
Author(s):  
Anastassia V. Komarova ◽  
Ludmila S. Tchufistova ◽  
Marc Dreyfus ◽  
Irina V. Boni

ABSTRACT We have shown previously that when the Escherichia coli chromosomal lacZ gene is put under the control of an extended Shine-Dalgarno (SD) sequence (10 or 6 nucleotides in length), the translation efficiency can be highly variable, depending on the presence of AU-rich targets for ribosomal protein S1 in the mRNA leader. Here, the same strains have been used to examine the question of how strong ribosome binding to extended SD sequences affects the stability of lacZ mRNAs translated with different efficiencies. The steady-state concentration of the lacZ transcripts has been found to vary over a broad range, directly correlating with translation efficiency but not with the SD duplex stability. The observed strain-to-strain variations in lacZ mRNA level became far less marked in the presence of the rne-1 mutation, which partially inactivates RNase E. Together, the results show that (i) an SD sequence, even one that is very long, cannot stabilize the lacZ mRNA in E. coli if translation is inefficient; (ii) inefficiently translated lacZ transcripts are sensitive to RNase E; and (iii) AU-rich elements inserted upstream of a long SD sequence enhance translation and stabilize mRNA, despite the fact that they constitute potential RNase E sites. These data strongly support the idea that the lacZ mRNA in E. coli can be stabilized only by translating, and not by stalling, ribosomes.


1992 ◽  
Vol 287 (2) ◽  
pp. 573-578 ◽  
Author(s):  
M Ishikawa ◽  
T Kubo ◽  
S Natori

A protein with a molecular mass of 8 kDa was found to be synthesized specifically when the fat-body from injured Sarcophaga peregrina larvae was cultured in vitro. This protein was purified from the haemolymph of the injured larvae to near-homogeneity. Partial amino acid sequencing revealed that this protein is a diptericin homologue. It showed bactericidal activity on growing, but not resting Escherichia coli cells. E. coli cells become elongated on treatment with this protein.


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