Table 3.

Chronological Advancements in Proteomic Analysis of Cryptosporidium Species.

Year	The Greatest Milestone	Outcome of Study	Reference
2000	Initial proteomic study of whole and freeze–thawed C. parvum oocysts and freeze–thawed C. muris	✓Identify spectral peaks that can distinguish Cryptosporidium at the genus level, as well as specific peaks that enable differentiation between C. parvum and C. muris oocysts ✓The pioneering utilization of MALDI-TOF peptide mass fingerprinting (PMF) for Cryptosporidium oocysts analysis	[24]
2007	Proteomic analysis of C. parvum oocysts	✓Improvements in the sample preparation before analysis using MALDI-TOF peptide mass fingerprinting (PMF) ✓Spectral peaks that were specific to the oocyst and sporozoites	[25]
2007	Large-scale global proteomic analysis of non-excyted and excyted C. parvum sporozoites	✓Identification of around 200 proteins, representing about 6% of the predicted proteome ✓Twenty-six proteins were found to have significantly higher expression levels post-excystation relative to unexcysted oocyst	[27]
2008	In-depth analysis of the expressed protein repertoire of C. parvum	✓A total of 642. 282 and 1154 non-redundant proteins were identified from the 1-DE, 2-DE, and MudPIT analyses, respectively ✓A total of 1237 non-redundant proteins were identified from excysted oocysts and sporozoites	[28]
2010	Proteome analysis for identifying the key components of the C. parvum oocyst wall	✓COWPs constitute about 75% of the proteins identified in the oocyst walls ✓COWP1 is the dominant oocyst wall protein	[29]
2013	Proteome analysis of C. parvum sporozoites	✓In total, 135 hits were recorded from the analysis of all 20 gel slices, 41% of which were unique hits for Cryptosporidium	[30]
2015	Proteomic analysis of rhoptry-enriched fractions from C. parvum	✓Twenty-two potential novel rhoptry proteins were detected ✓Novel candidate proteins may be considered targets for researching the invasion pathway of C. parvum and the pathogenic mechanisms of rhoptry proteins	[31]
2021	Proteomic analysis of C. andersoni oocysts before and after excystation	✓A total of 1586 proteins were identified ✓A total of 17 of 1586 were differentially expressed proteins (DEPs) upon excystation and had multiple biological functions associated with control of gene expression at the level of transcription and biosynthetic and metabolic processes	[32]
2021	Proteomic analysis of Cryptosporidium spp. from clinical samples	✓Utility of the purification method for oocysts from clinical stool samples ✓Implementation of MALDI-TOF MS for clinical sample analysis	[35]
2021	Assessing the effectiveness of cow colostrum for treating cryptosporidiosis in calves and its impact on serum proteomes	✓The use of colostrum in the treatment of cryptosporidiosis affects the serum proteomes of calves ✓Serum amyloid A was the most altered proteome in the sera of calves with colostral treatment	[33]
2021	Characterize the changes to the proteome induced by C. parvum infection	✓Among 4406 proteins identified, 121 proteins were identified as differentially abundant in C. parvum infected HCT-8 cells compared with uninfected cells ✓A wide range of functional proteins that participate in host anti-parasite immunity or act as potential targets during infection provides new insights into the molecular mechanism of C. parvum infection	[34]
2021	Investigation of the underlying biochemical interaction in C57BL/6J mice infected with C. parvum	✓Glycolysis and glutaminolysis were significantly impacted in the jejunum and ileum during cryptosporidiosis ✓Gut microbiome response to cryptosporidiosis was detected via increased levels of D-amino acids and SCFAs ✓Ability of multi-omics to contribute a robust understanding of gut infections and demonstrates the previously unreported infection interactomics as the parasite passes through the gut	[26]