Label-Free Quantitative Proteomic Analysis of Harmless and Pathogenic Strains of Infectious Microalgae, Prototheca spp.

Jayaseelan Murugaiyan,Uwe Roesler,Christoph Weise,Murat Eravci

doi:10.3390/ijms18010059

Jayaseelan Murugaiyan, Uwe Roesler + Show 2 more

Open Access

https://doi.org/10.3390/ijms18010059

Copy DOI

Abstract

Microalgae of the genus Prototheca (P.) spp are associated with rare algal infections of invertebrates termed protothecosis. Among the seven generally accepted species, P. zopfii genotype 2 (GT2) is associated with a severe form of bovine mastitis while P. blaschkeae causes the mild and sub-clinical form of mastitis. The reason behind the infectious nature of P. zopfii GT2, while genotype 1 (GT1) remains non-infectious, is not known. Therefore, in the present study we investigated the protein expression level difference between the genotypes of P. zopfii and P. blaschkeae. Cells were cultured to the mid-exponential phase, harvested, and processed for LC-MS analysis. Peptide data was acquired on an LTQ Orbitrap Velos, raw spectra were quantitatively analyzed with MaxQuant software and matching with the reference database of Chlorella variabilis and Auxenochlorella protothecoides resulted in the identification of 226 proteins. Comparison of an environmental strain with infectious strains resulted in the identification of 51 differentially expressed proteins related to carbohydrate metabolism, energy production and protein translation. The expression level of Hsp70 proteins and their role in the infectious process is worth further investigation. All mass spectrometry data are available via ProteomeXchange with identifier PXD005305.

Highlights

Present achlorophyllous microalgae of the genus Prototheca (P) spp. are associated with rare but severe infections in animals and humans termed protothecosis
With the recent reclassification of a strain isolated from a human patient, the genus Prototheca currently includes seven generally accepted species, among which P. blaschkeae, P. cutis, P. miyajii, P. wickerhamii and P. zopfii have been reported to be associated with infections [1,2,3,4,5]
P. cutis, P. miyajii and P. zopfii, P. wickerhamii have been reported as associated with human protothecosis, while P. blaschkeae, P. wickerhamii and P. zopfii were reported to be the most common species involved in animal protothecosis including the dreadful bovine mastitis [4,5,6]

Summary

Introduction

Present achlorophyllous microalgae of the genus Prototheca (P) spp. (family Chlorellaceae) are associated with rare but severe infections in animals and humans termed protothecosis. With the recent reclassification of a strain isolated from a human patient, the genus Prototheca currently includes seven generally accepted species, among which P. blaschkeae, P. cutis, P. miyajii, P. wickerhamii and P. zopfii have been reported to be associated with infections [1,2,3,4,5]. Despite the association of P. zopfii GT2 and P. blaschkeae with bovine mastitis, their difference in pathogenicity, their reservoir in the cow shed and its surroundings and the Prototheca genome sequence is not known [2,15]. Proteomic analysis of P. zopfii genotypes and a comparison with P. blaschkeae might help us to better understand the pathogenic nature of Prototheca spp. Label-free quantitative proteomics was applied to detect differences in the protein expression between non-pathogenic P. zopfii GT1 and those species associated with severe and subclinical bovine mastitis, P. zopfii GT2 and P. blaschkeae

Methods

Results

Conclusion