Humoral immune response of Galleria mellonella larvae after infection by Beauveria bassiana under optimal and heat-shock conditions

Wojda, Iwona; Kowalski, Patryk; Jakubowicz, Teresa

doi:10.1016/j.jinsphys.2009.01.014

Cited by 109 publications

(89 citation statements)

References 50 publications

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“…The potency of antifungal peptides depends on the fungal species, and possibly even the strain [31,32], with genes of the broad-spectrum AMPs being activated by a disparate range of elicitors [33]. Nevertheless, our data confirm that increased expression of Gallerimycin, Galiomicin and Cecropin occurs in (non-melanic) G. mellonella larvae naturally infected with B. bassiana [33,34]. Gloverin was highly upregulated by topical fungal infection in both G. mellonella morphs, which is in agreement with its recently discovered activity against bacteria and fungi [35].…”

Section: Discussionmentioning

confidence: 53%

More than a colour change: insect melanism, disease resistance and fecundity

et al. 2013

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A 'dark morph' melanic strain of the greater wax moth, Galleria mellonella, was studied for its atypical, heightened resistance to infection with the entomopathogenic fungus, Beauveria bassiana. We show that these insects exhibit multiple intraspecific immunity and physiological traits that distinguish them from a non-melanic, fungus-susceptible morph. The melanic and non-melanic morphs were geographical variants that had evolved different, independent defence strategies. Melanic morphs exhibit a thickened cuticle, higher basal expression of immunity-and stress-management-related genes, higher numbers of circulating haemocytes, upregulated cuticle phenoloxidase (PO) activity concomitant with conidial invasion, and an enhanced capacity to encapsulate fungal particles. These insects prioritize specific augmentations to those frontline defences that are most likely to encounter invading pathogens or to sustain damage. Other immune responses that target late-stage infection, such as haemolymph lysozyme and PO activities, do not contribute to fungal tolerance. The net effect is increased larval survival times, retarded cuticular fungal penetration and a lower propensity to develop haemolymph infections when challenged naturally (topically) and by injection. In the absence of fungal infection, however, the heavy defence investments made by melanic insects result in a lower biomass, decreased longevity and lower fecundity in comparison with their non-melanic counterparts. Although melanism is clearly correlated with increased fungal resistance, the costly mechanisms enabling this protective trait constitute more than just a colour change.

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Section: Discussionmentioning

confidence: 53%

More than a colour change: insect melanism, disease resistance and fecundity

et al. 2013

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“…To check this, larvae were infected with this bacterium and the gene expression of four selected antimicrobial peptides was monitored 1, 5, and 16 h postinfection. The selected genes coded for the cysteine-rich antifungal peptide gallerimycin (47), a defensin called galliomycin (48), lysozyme, and an inducible metalloproteinase inhibitor (IMPI) (47). Gene expression was determined by quantitative RT-PCR analysis of the total RNA extracted for each postinfection time point.…”

Section: In Vitro Infection Of Hemocytesmentioning

confidence: 99%

The Virulence of Salmonella enterica Serovar Typhimurium in the Insect Model Galleria mellonella Is Impaired by Mutations in RNase E and RNase III

Viegas

Mil‐Homens

Fialho

et al. 2013

Appl Environ Microbiol

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Salmonella enterica serovar Typhimurium is a Gram-negative bacterium able to invade and replicate inside eukaryotic cells. To cope with the host defense mechanisms, the bacterium has to rapidly remodel its transcriptional status. Regulatory RNAs and ribonucleases are the factors that ultimately control the fate of mRNAs and final protein levels in the cell. There is growing evidence of the direct involvement of these factors in bacterial pathogenicity. In this report, we validate the use of a Galleria mellonela model in S. Typhimurium pathogenicity studies through the parallel analysis of a mutant with a mutation in hfq, a wellestablished Salmonella virulence gene. The results obtained with this mutant are similar to the ones reported in a mouse model. Through the use of this insect model, we demonstrate a role for the main endoribonucleases RNase E and RNase III in Salmonella virulence. These ribonuclease mutants show an attenuated virulence phenotype, impairment in motility, and reduced proliferation inside the host. Interestingly, the two mutants trigger a distinct immune response in the host, and the two mutations seem to have an impact on distinct bacterial functions. Salmonella infections are a serious medical and veterinary problem worldwide. This pathogenic bacterium is able to invade and replicate within eukaryotic host cells. For infection, Salmonella relies upon a range of laterally acquired virulence regions, the so-called Salmonella pathogenicity islands (SPIs). Of these, SPI-1 and SPI-2 contain genes that encode type III secretion systems (TTSS), which deliver effector proteins into host cells to facilitate either cellular invasion or intracellular survival, respectively (for a review, see reference 1). Hundreds of genes are upregulated during infection and play important roles in adaptation, survival, and proliferation within mammalian cells (2). Transcriptome analysis of Salmonella enterica serovar Typhimurium within epithelial cells and macrophages revealed distinct patterns of expression linked to the different stages of infection (3, 4).Both the evolutionarily close relationship with Escherichia coli and the pathogen-specific aspects make Salmonella a very good model for studying the influence of RNA determinants in bacterial pathogenicity. In addition to transcriptional control, regulation of RNA decay has emerged as a major pathway in the fast adaptive process of bacteria to changes in the environment. RNAs may also act as regulatory molecules that can directly sense environmental clues and modulate the expression of target RNAs (for a review, see reference 5). The fate of RNA transcripts can be also controlled by proteins, including ribonucleases (RNases) and RNA chaperones.RNases are enzymes that govern the maturation and degradation of RNA molecules. RNA decay in Gram-negative bacteria usually begins with an endonucleolytic cleavage at one or more internal sites on the RNA molecule. This cleavage is normally performed by RNase E and/or RNase III (6, 7). The single-stranded specific endori...

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“…Binding of 17-DMAG to Hsp90 would to a certain extent "mimic" the heat shock. Indeed studies currently ongoing in our laboratory indicate enhanced resistance of infected G. mellonella exposed to heatshock conditions ( [47] and unpublished observations). Looking from the perspective of the evolution of the immune system, it is known that Hsp90 via Hsf-1 plays an important role in the immune response of some invertebrates.…”

Section: Discussionmentioning

confidence: 76%

Galleria mellonella infected with Bacillus thuringiensis involves Hsp90

Wojda

Kowalski

2013

Open Life Sciences

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Insects are good models for studying the innate immune response. We report that Galleria mellonella larvae infected with entomopathogenic bacteria Bacillus thuringiensis kurstaki show changes in the level of Hsp90. Our experimental approach was to pre-treat larvae with the Hsp90-binding compound, 17-DMAG, before infection with B. thuringiensis. We show that pre-treated animals display a higher level of immune response. This was mainly manifested by enhanced action of their hemolymph directed toward living bacteria as well as lysozyme activity digesting bacterial peptidoglycan. The observed phenomenon was due to the higher activity of antimicrobial peptides which, in contrast to healthy animals, was detected in the hemolymph of the immunestimulated larvae. Finally, the physiological significance of our observation was highlighted by the fact that G. mellonella pre-treated with 17-DMAG showed a prolonged survival rate after infection with B. thuringiensis than the control animals. Our report points to a role for Hsp90 in the immune response of G. mellonella after infection with B. thuringiensis at the optimal growth temperature.

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Humoral immune response of Galleria mellonella larvae after infection by Beauveria bassiana under optimal and heat-shock conditions

Cited by 109 publications

References 50 publications

More than a colour change: insect melanism, disease resistance and fecundity

More than a colour change: insect melanism, disease resistance and fecundity

The Virulence of Salmonella enterica Serovar Typhimurium in the Insect Model Galleria mellonella Is Impaired by Mutations in RNase E and RNase III

Galleria mellonella infected with Bacillus thuringiensis involves Hsp90

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