title: Enhanced intracellular survival and epithelial cell adherence abilities of Burkholderia pseudomallei morphotypes are dependent on differential expression of virulence-associated proteins during mid-logarithmic growth phase.
abstract: Colony morphology variation is a characteristic of Burkholderia pseudomallei primary clinical isolates, associated with variations in expression of virulence factors. Here, we performed comparative investigations on adhesion, invasion, plaque-forming abilities and protein profiles of B. pseudomallei wild-type (WT) and a small colony variant (SCV). The percentage of SCV adherence to A549 cells was significantly higher (2.73%) than WT (1.91%). In contrast, WT was significantly more efficient (0.63%) than SCV (0.31%) in invasiveness and in inducing cellular damage. Using 2-DE and MALDI TOF/TOF, 263 and 258 protein spots were detected in WT and SCV, respectively. Comparatively, 49 proteins were differentially expressed in SCV when compared with WT. Of these, 31 proteins were up-regulated, namely, nucleoside diphosphate kinase (Ndk), phosphoglycerate kinase (Pgk), thioredoxin (TrxA), putative ferritin DPS-family DNA-binding protein (DPS) and oxidoreductase (AhpC) that are known to be involved in adhesion, intracellular survival and persistence. However, among the 18 down-regulated proteins, enolase (Eno), elongation factor (EF-Tu) and universal stress-related proteins were associated with invasion and virulence. Differences observed in these protein profiles provide ample clues to their association with the morphotypic and phenotypic characteristics of colony variants, providing additional insights into the potential association of B. pseudomallei colony morphotypes with disease pathogenesis.
  
  
  CONCLUSIONS
  Comparative analyses were performed on the ability of wild-type and small colony variant of B. pseudomallei to adhere, invade and form plaques on human epithelial cells. In addition, proteomic analysis of these different colony morphotypes was also carried out. This research provides insights into the virulence and pathogenesis attributes of B. pseudomallei and contributes to better understand the pathogenesis of melioidosis.
authors.affiliation: Tropical Infectious Disease Research and Education Center (TIDREC), Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur, Malaysia.
authors.forename: Anis Rageh
authors.initials: AR
authors.lastname: Al-Maleki
authors.affiliation: Tropical Infectious Disease Research and Education Center (TIDREC), Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur, Malaysia.
authors.forename: Vanitha
authors.initials: V
authors.lastname: Mariappan
authors.affiliation: Tropical Infectious Disease Research and Education Center (TIDREC), Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur, Malaysia.
authors.forename: Kumutha Malar
authors.initials: KM
authors.lastname: Vellasamy
authors.affiliation: Tropical Infectious Disease Research and Education Center (TIDREC), Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur, Malaysia.
authors.forename: Esaki Muthu
authors.initials: EM
authors.lastname: Shankar
authors.affiliation: Tropical Infectious Disease Research and Education Center (TIDREC), Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur, Malaysia.
authors.forename: Sun Tee
authors.initials: ST
authors.lastname: Tay
authors.affiliation: Tropical Infectious Disease Research and Education Center (TIDREC), Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur, Malaysia. Electronic address: jamuna@um.edu.my.
authors.forename: Jamuna
authors.initials: J
authors.lastname: Vadivelu
mesh_terms: D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D016957:Burkholderia pseudomallei / Q000166:cytology* / Q000472:pathogenicity; D045744:Cell Line, Tumor; D030562:Databases, Protein; D004847:Epithelial Cells / Q000382:microbiology*; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D013058:Mass Spectrometry; D008554:Melioidosis / Q000382:microbiology; D020543:Proteome; D040901:Proteomics; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D015415:Biomarkers; D020543:Proteome; D037521:Virulence Factors
keywords: Burkholderia pseudomallei; Colony variants; Pathogenesis; Proteomics