Effect of Bodily Fluids from Honey Bee (Apis mellifera) Larvae on Growth and Genome-Wide Transcriptional Response of the Causal Agent of American Foulbrood Disease (Paenibacillus larvae)

Lina De Smet,Dieter De Koker,Dirk C De Graaf,Alyse K Hawley,Paul De Vos,Leonard J Foster,Olle Terenius

doi:10.1371/journal.pone.0089175

Lina De Smet, Dieter De Koker + Show 5 more

Open Access

https://doi.org/10.1371/journal.pone.0089175

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Journal: PloS one	Publication Date: Feb 20, 2014
Citations: 73	License type: CC BY 4.0

Affiliation: Ghent University, University of British Columbia

Abstract

Paenibacillus larvae, the causal agent of American Foulbrood disease (AFB), affects honey bee health worldwide. The present study investigates the effect of bodily fluids from honey bee larvae on growth velocity and transcription for this Gram-positive, endospore-forming bacterium. It was observed that larval fluids accelerate the growth and lead to higher bacterial densities during stationary phase. The genome-wide transcriptional response of in vitro cultures of P. larvae to larval fluids was studied by microarray technology. Early responses of P. larvae to larval fluids are characterized by a general down-regulation of oligopeptide and sugar transporter genes, as well as by amino acid and carbohydrate metabolic genes, among others. Late responses are dominated by general down-regulation of sporulation genes and up-regulation of phage-related genes. A theoretical mechanism of carbon catabolite repression is discussed.

Highlights

American Foulbrood (AFB) is a devastating brood disease affecting honey bee health worldwide [1]
We studied the effect of larval bodily fluids on P. larvae gene expression by in vitro exposure of bacterial cultures to larval fluids
In addition higher bacterial densities are observed as a result of larval fluid treatment (Figure 2)

Summary

Introduction

American Foulbrood (AFB) is a devastating brood disease affecting honey bee health worldwide [1]. Honey bee larvae are degraded to brownish glue-like remains (ropy stage), which thereafter dries down to hard foulbrood scales containing approximately 2.5 billion spores [5]. Many countries followed an eradication procedure with destruction by burning This drastic act seemed necessary for annihilation of the persistent and resistant spores [6,7], until it was proven that large discrepancies exist between the number of outbreaks and the spread of spores [8]. This practice, does not affect the infectious spore stage and leads to antibiotic resistance [9] and contamination in the honey [10]. Such research is facilitated by the availability of the P. larvae genome sequence [19,20] and it is within this conceptual framework that the present study was undertaken

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Conclusion