Comparative proteome analysis of secreted proteins of Streptococcus suis serotype 9 isolates from diseased and healthy pigs.
Streptococcus suis is an important swine pathogen responsible for a variety of human diseases. Investigations of virulence factors have focused on S. suis serotype 2 strains (SS2), which are the most invasive isolates worldwide. However, S. suis serotype 9 (SS9) is also a prevalent serotype. Unlike SS2, little is known about virulence factors for SS9. The two strains, GZ0565 and SH040917, were isolated from a diseased pig and a healthy pig, respectively. The virulence of these two SS9 strains was evaluated in zebrafish. The 50% lethal dose value of strain GZ0565 was 3.8x10(5)cfu/fish, while zebrafish injected with strain SH040917 exhibited no mortalities. For revealing proteins probably involved in different pathogenicity, a comparative proteomics approach was used to distinguish between the two-dimensional electrophoresis profiles of secreted proteins in two strains. With the use of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and MALDI-TOF/TOF-MS, protein spots that were unique to strain GZ0565 were identified, and led to the identification of 13 candidate proteins. The largest proportion of these proteins was metabolism-related. Five of the proteins are putative virulence-associated factors: DNA nuclease, o-acetylserine lyase, peptidoglycan-binding LysM, phosphoglycerate mutase, and putative 5'-nucleotidase. These findings contribute to the understanding of SS9 pathogenic mechanisms.
Wu
Zongfu
Z
Key Laboratory of Animal Disease Diagnostic and Immunology, Ministry of Agriculture, Nanjing Agricultural University, Weigang 1, Nanjing 210095, Jiangsu, PR China.
Zhang
Wei
W
Lu
Chengping
C
D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D008969:Molecular Sequence Data; D011506:Proteins / Q000235:genetics; D040901:Proteomics / Q000379:methods; D013290:Streptococcal Infections / Q000382:microbiology / Q000662:veterinary*; D017011:Streptococcus suis / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism* / Q000472:pathogenicity*; D013552:Swine / Q000382:microbiology*; D013553:Swine Diseases / Q000382:microbiology*; D014774:Virulence; D015027:Zebrafish
D001426:Bacterial Proteins; D011506:Proteins