Surface Immunoproteomics Reveals Potential Biomarkers in Alicyclobacillus acidoterrestris

Yiheng Shi,Tianli Yue,Jianping Wei,Yipei Zhang,Yahong Yuan

doi:10.3389/fmicb.2018.03032

Abstract

Alicyclobacillus acidoterrestris is a major putrefying bacterium that can cause pecuniary losses in the global juice industry. Current detection approaches are time-consuming and exhibit reduced specificity and sensitivity. In this study, an immunoproteomic approach was utilized to identify specific biomarkers from A. acidoterrestris for the development of new detection methods. Cell surface-associated proteins were extracted and separated by 2-D (two-dimensional) gel electrophoresis. Immunogenic proteins were detected by Western blot analysis using antisera against A. acidoterrestris. Twenty-two protein spots exhibiting immunogenicity were excised and eighteen of the associated spots were successfully identified by matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry (MALDI-TOF/TOF MS). These proteins were observed to be involved in energy and carbohydrate metabolism, transmembrane transport, response to oxidative stress, polypeptide biosynthesis, and molecule binding activity. This is the first report detailing the identification of cell surface-associated antigens of A. acidoterrestris. The identified immunogenic proteins could serve as potential targets for the development of novel detection methods.

Highlights

Alicyclobacillus acidoterrestris is a thermo-acidophilic, aerobic, spore-forming, Gram-positive bacterium which is capable of growing at a temperature range of 25–60◦C, and a pH range of 2.5– 6.0 (Chang et al, 2013)
The fact that no interaction partners were identified for either N007_08970 or N007_04435 (Figure 3), illustrates their novelty as antigens from a different perspective. This is the first study to report the occurrence of specific antigens in the cell surface of A. acidoterrestris, a species that causes fruit juice contamination leading to significant economic losses
The other antigens that were identified as part of this study are homologs of antigens reported in pathogenic species and could act as biomarkers

Summary

Introduction

Alicyclobacillus acidoterrestris is a thermo-acidophilic, aerobic, spore-forming, Gram-positive bacterium which is capable of growing at a temperature range of 25–60◦C, and a pH range of 2.5– 6.0 (Chang et al, 2013). The spores that are produced by A. acidoterrestris can germinate and grow at pH < 4 and are capable of resisting heat treatment at 90◦C for 16 to 23 min, a more stringent heat treatment regimen than the conventional pasteurization treatments used in juice processing (Steyn et al, 2011; Celenk and Ayse Handan, 2015). A. acidoterrestris can use vanillin and tyrosine as precursors in the synthesis of guaiacol, an organic compound that emits a “phenolic” odor (Uchida and Silva, 2017). The latter compound triggers spoilage of fruit juices and acidic beverages, resulting in significant economic losses to the juice industry (Oteiza et al, 2015; Fernandez et al, 2017). Current detection methods are either labor-intensive and time-consuming or highly technique-requiring

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