AUTHOR=Zhou Qi , Feng Saixiang , Zhang Jianmin , Jia Aiqing , Yang Kaijie , Xing Kaixiang , Liao Ming , Fan Huiying 

TITLE=Two Glycosyltransferase Genes of Haemophilus parasuis SC096 Implicated in Lipooligosaccharide Biosynthesis, Serum Resistance, Adherence, and Invasion

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=6

YEAR=2016

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2016.00100

DOI=10.3389/fcimb.2016.00100

ISSN=2235-2988

ABSTRACT=<p><italic>Haemophilus parasuis</italic> is a common opportunistic pathogen known for its ability to colonize healthy piglets and causes Glässer's disease. The lipooligosaccharide (LOS) of <italic>H. parasuis</italic> is a potential virulence-associated factor. In this study, two putative glycosyltransferases that might be involved in LOS synthesis in <italic>H. parasuis</italic> SC096 were identified (<italic>lgtB</italic> and <italic>lex-1</italic>). Mutants were constructed to investigate the roles of the <italic>lgtB</italic> and <italic>lex-1</italic> genes. The LOS from the Δ<italic>lgtB</italic> or Δ<italic>lex-1</italic> mutant showed truncated structure on silver-stained SDS-PAGE gel compared to the wild-type strain. The Δ<italic>lgtB</italic> and Δ<italic>lex-1</italic> mutants were significantly more sensitive to 50% porcine serum, displaying 15.0 and 54.46% survival rates, respectively. Complementation of the <italic>lex-1</italic> mutant restored the serum-resistant phenotype. Additionally, the Δ<italic>lgtB</italic> and Δ<italic>lex-1</italic> strains showed impaired ability to adhere to and invade porcine kidney epithelial cells (PK-15). The above results suggested that the <italic>lgtB</italic> and <italic>lex-1</italic> genes of the <italic>H. parasuis</italic> SC096 strain participated in LOS synthesis and were involved in serum resistance, adhesion and invasion.</p>