Linking Bacillus cereus Genotypes and Carbohydrate Utilization Capacity.

Alicja K Warda,Jos Boekhorst,Roland J Siezen,Oscar P Kuipers,Masja N Nierop Groot,Anne De Jong,Tjakko Abee,Marjon H J Wells-Bennik,Chih-Horng Kuo

doi:10.1371/journal.pone.0156796

Abstract

We characterised carbohydrate utilisation of 20 newly sequenced Bacillus cereus strains isolated from food products and food processing environments and two laboratory strains, B. cereus ATCC 10987 and B. cereus ATCC 14579. Subsequently, genome sequences of these strains were analysed together with 11 additional B. cereus reference genomes to provide an overview of the different types of carbohydrate transporters and utilization systems found in B. cereus strains. The combined application of API tests, defined growth media experiments and comparative genomics enabled us to link the carbohydrate utilisation capacity of 22 B. cereus strains with their genome content and in some cases to the panC phylogenetic grouping. A core set of carbohydrates including glucose, fructose, maltose, trehalose, N-acetyl-glucosamine, and ribose could be used by all strains, whereas utilisation of other carbohydrates like xylose, galactose, and lactose, and typical host-derived carbohydrates such as fucose, mannose, N-acetyl-galactosamine and inositol is limited to a subset of strains. Finally, the roles of selected carbohydrate transporters and utilisation systems in specific niches such as soil, foods and the human host are discussed.

Highlights

Metabolic activity and growth of bacteria requires energy that can be acquired during carbohydrate catabolism
The phylogenetic clustering of the strains is in line with the phylogenetic division of the B. cereus sensu lato group members based on the panC polymorphism published by Guinebretière [22] and the B. cereus strains of our study were found to belong to groups II, III, IV and VI
In the API assay, all 22 tested B. cereus strains were found to grow on D-glucose, D-fructose, D-maltose, D-trehalose, N-acetylglucosamine and D-ribose, with the majority of the strains growing on sucrose, arbutin, esculin, salicin, and starch/glycogen

Summary

Introduction

Metabolic activity and growth of bacteria requires energy that can be acquired during carbohydrate catabolism. Carbohydrates can be present in nature in complex forms such as polysaccharides including starch, cellulose or glycogen, and as mono- and disaccharides exemplified by glucose and sucrose. Efficient use of available carbohydrates by microorganisms is determined by the different types of carbohydrate transporters and utilization systems encoded by chromosome- and plasmid-located genes and gene clusters [1,2]. Expression and regulation of sugar utilisation systems can be affected by environmental conditions such as oxygen availability and temperature, and carbon catabolite repression (CCR) [1,3,4]. Systems for carbohydrate uptake and metabolism predicted based on genome analysis can vary significantly between species and strains as shown for Escherichia coli [5], Bacillus subtilis.

Methods

Results

Conclusion