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.
Key Laboratory of Animal Disease Diagnostic and Immunology, Ministry of Agriculture, Nanjing Agricultural University, Weigang 1, Nanjing 210095, Jiangsu, PR China.
Zongfu
Z
Wu
Wei
W
Zhang
Chengping
C
Lu
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