Losing the battle against fungal infection: Suppression of termite immune defenses during mycosis

Avulova, Svetlana; Rosengaus, Rebeca B.

doi:10.1016/j.jinsphys.2011.04.009

Cited by 20 publications

(13 citation statements)

References 32 publications

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“…Hence, it is not surprising to see that parasitoids and entomopathogenic fungi evolved mechanisms to specifically suppress hemocytic immune functions of their hosts. Several fungal species increase host THC after infection (Mishra, Kumar, & Malik, ; Sewify & Hashem, ) and other studies report that the THC of host insects decreases after fungal infection (Avulova & Rosengaus, ; Bandani, ). Decreasing the THC may led to cellular immunosuppression, which would favor the infecting fungus.…”

Section: Discussionmentioning

confidence: 96%

The entomopathogenic fungusNomuraea rileyiimpairs cellular immunity of its hostHelicoverpa armigera

Zhong

Liu

Wang

et al. 2017

Arch Insect Biochem Physiol

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In this study, we investigated the effect of the entomopathogenic fungus Nomuraea rileyi on Helicoverpa armigera cellular immune responses. Nomuraea rileyi infection had no effect on total hemocyte count (THC), but impaired hemocyte-mediated phagocytosis, nodulation, and encapsulation responses. Nomuraea rileyi infection led to a significant reduction in hemocyte spreading. An in vitro assay revealed that plasma from N. rileyi infected H. armigera larvae suppressed the spreading ability of hemocytes from naïve larvae. We infer that N. rileyi suppresses the cellular immune response of its host, possibly by secreting exogenous, cytotoxic compounds into the host's hemolymph.

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Section: Discussionmentioning

confidence: 96%

The entomopathogenic fungusNomuraea rileyiimpairs cellular immunity of its hostHelicoverpa armigera

Zhong

Liu

Wang

et al. 2017

Arch Insect Biochem Physiol

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“…These differences in the action of both fungi are likely due to a stronger effect of M. anisopliae when compared to I. fumosorosea. For example, M. anisopliae produces immunosuppressor toxins like destruxin [ 48 ] that may lead to damage hemocytes [ 49 ] and cause insect paralysis ( via an increased calcium level in Malpighian tubules) [ 50 ]. These effects take place possibly due to the ability of M. anisopliae to produce a collagenous coat of hyphal bodies that mask the recognition of β-1,3-glucans by the insect immune system [ 51 ].…”

Section: Discussionmentioning

confidence: 99%

“…In relation to this, fungal infection using Beauveria bassiana in the migratory grasshopper Melanoplus sanguinipes [ 62 ] and of M. anisopliae in the locust Schistocerca gregaria [ 29 , 63 ], led to a reduction in hemocyte number. One way this negative action can occur is via the use of fungal mycotoxins such as destruxin [ 48 ]. This compound reduces PO activity, phagocytosis and encapsulation [ 52 ].…”

Section: Discussionmentioning

confidence: 99%

Survival and immune response of the Chagas vector Meccus pallidipennis (Hemiptera: Reduviidae) against two entomopathogenic fungi, Metarhizium anisopliae and Isaria fumosorosea

et al. 2016

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BackgroundChagas disease is a key health problem in Latin America and is caused and transmitted by Trypanosoma cruzi and triatomine bugs, respectively. Control of triatomines has largely relied on the use pyrethroids, which has proved to be ineffective in the long term. Alternatively, the use of entomopathogenic fungi has been implemented to control triatomine bugs. These fungi are highly efficient as they induce a reduction in immune response on insects. Meccus pallidipennis is the main triatomine vector of Chagas disease in Mexico. In this work we investigated the effects of two entomopathogenic fungi, Metarhizium anisopliae and Isaria fumosorosea, on M. pallidipennis nymphs in terms of insect survival and immune response.MethodsWe had an infected and a control group for each fungal species and assessed: a) insect survival during 30 days; and, b) phenoloxidase (PO) and prophenoloxidase (proPO; two key traits in insect immune response) at 24, 48, 96 and 144 h. For survival we used Kaplan-Meier survival analysis while for immune response we used factorial, repeated-measures ANOVA for each fungal species.ResultsAnimals treated with M. anisopliae died sooner than animals treated with I. fumosorosea. Infected animals showed lower PO and proPO values than sham individuals, with a clear decrease in these parameters at 24 h with no further changes after this time.ConclusionsOur study widens the possibility of entomopathogenic fungi being used for triatomine control. The negative effect on PO and proPO seems mediated by a down-regulation of the triatomine immune response.

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“…They suggested that the reduction in hemocytes number directly related with the appearance of hyphal bodies. Moreover, the invading conidia of M. anisopliae overtake the cellular immune response by destroying hemocytes of Z. angusticollis [17]. More recently, 182 expressed sequence tags (ESTs) were obtained by suppression subtractive hybridization from Reticulitermes flavipes infected with M. anisopliae .…”

Section: Introductionmentioning

confidence: 99%

Immune-Related Transcriptome of Coptotermes formosanus Shiraki Workers: The Defense Mechanism

Hussain

et al. 2013

PLoS ONE

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Formosan subterranean termites, Coptotermes formosanus Shiraki, live socially in microbial-rich habitats. To understand the molecular mechanism by which termites combat pathogenic microbes, a full-length normalized cDNA library and four Suppression Subtractive Hybridization (SSH) libraries were constructed from termite workers infected with entomopathogenic fungi (Metarhizium anisopliae and Beauveria bassiana), Gram-positive Bacillus thuringiensis and Gram-negative Escherichia coli, and the libraries were analyzed. From the high quality normalized cDNA library, 439 immune-related sequences were identified. These sequences were categorized as pattern recognition receptors (47 sequences), signal modulators (52 sequences), signal transducers (137 sequences), effectors (39 sequences) and others (164 sequences). From the SSH libraries, 27, 17, 22 and 15 immune-related genes were identified from each SSH library treated with M. anisopliae, B. bassiana, B. thuringiensis and E. coli, respectively. When the normalized cDNA library was compared with the SSH libraries, 37 immune-related clusters were found in common; 56 clusters were identified in the SSH libraries, and 259 were identified in the normalized cDNA library. The immune-related gene expression pattern was further investigated using quantitative real time PCR (qPCR). Important immune-related genes were characterized, and their potential functions were discussed based on the integrated analysis of the results. We suggest that normalized cDNA and SSH libraries enable us to discover functional genes transcriptome. The results remarkably expand our knowledge about immune-inducible genes in C. formosanus Shiraki and enable the future development of novel control strategies for the management of Formosan subterranean termites.

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Losing the battle against fungal infection: Suppression of termite immune defenses during mycosis

Cited by 20 publications

References 32 publications

The entomopathogenic fungusNomuraea rileyiimpairs cellular immunity of its hostHelicoverpa armigera

The entomopathogenic fungusNomuraea rileyiimpairs cellular immunity of its hostHelicoverpa armigera

Survival and immune response of the Chagas vector Meccus pallidipennis (Hemiptera: Reduviidae) against two entomopathogenic fungi, Metarhizium anisopliae and Isaria fumosorosea

Immune-Related Transcriptome of Coptotermes formosanus Shiraki Workers: The Defense Mechanism

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