Ornithobacterium rhinotracheale has neuraminidase activity causing desialylation of chicken and turkey serum and tracheal mucus glycoproteins.
Neuraminidases (sialidases) are virulence factors of several poultry pathogens. Ornithobacterium rhinotracheale is a well known poultry pathogen causing respiratory disease in chickens and turkeys all over the world. We investigated whether O. rhinotracheale has neuraminidase enzymatic activity (NEAC). We tested NEAC in 47 O. rhinotracheale strains isolated from turkeys and chickens in eight countries. All strains showed relatively strong NEAC and considerable levels of NEAC were detected also in "cell-free supernatants" of their pelleted cells. Zymography using neuraminidase-specific chromogenic substrate indicated that a protein with molecular mass of ~40kDa and isoelectric point (pI) of ~8.0 is a putative neuraminidase of O. rhinotracheale. Notably, the genome of the type strain of O. rhinotracheale, DSM 15997 contains a gene (Ornrh_1957) encoding a putative neuraminidase with such Mw (39.5 kDa) and pI (8.5). We sequenced a corresponding genomic region of 20 O. rhinotracheale strains and found five distinct types of the neuraminidase gene (termed nanO) sequences. Most diversified nanO sequence was found in two strains isolated from chickens in Hungary in 1995. Their nanO sequences differ from that of the type strain (LMG 9086(T)) in 27 nucleotides. O. rhinotracheale neuraminidase showed capacity to cleave sialic acid from chicken and turkey glycoproteins. It cleaved sialic acid from SAα(2-6)gal moiety of their serum proteins, including immunoglobulin G (IgG) and transferrin. O. rhinotracheale also desialylated chicken and turkey tracheal mucus glycoprotens with SAα(2-3)gal moieties. This study provides the first evidence that O. rhinotracheale has neuraminidase which can desialylate glycoproteins of its natural hosts.
Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Groblje 3, 1230 Domžale, Slovenia.
Saša
S
Kastelic
Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Groblje 3, 1230 Domžale, Slovenia.
Rebeka Lucijana
RL
Berčič
Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Groblje 3, 1230 Domžale, Slovenia.
Ivanka
I
Cizelj
Institute for Pathological Physiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia.
Mateja
M
Benčina
Department of Microbiology and Infectious Diseases, Faculty of Veterinary Science, Szent István University, H-1143 Budapest, Hungary.
Laszlo
L
Makrai
Veterinary Faculty, University of Ljubljana, Gerbičeva 60, 1000 Ljubljana, Slovenia.
Olga
O
Zorman-Rojs
Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Groblje 3, 1230 Domžale, Slovenia.
Mojca
M
Narat
Department of Veterinary Pathobiology, Faculty of Life Science, University of Copenhagen, Denmark.
Magne
M
Bisgaard
Department of Veterinary Pathobiology, Faculty of Life Science, University of Copenhagen, Denmark.
Henrik
H
Christensen
Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Groblje 3, 1230 Domžale, Slovenia. Electronic address: dusan.bencina@bf.uni-lj.si.
Dušan
D
Benčina
D000818:Animals; D001798:Blood Proteins / Q000378:metabolism; D002645:Chickens; D045826:Flavobacteriaceae Infections / Q000097:blood / Q000201:enzymology / Q000378:metabolism / Q000662:veterinary*; D006023:Glycoproteins / Q000378:metabolism; D006814:Hungary; D007074:Immunoglobulin G / Q000378:metabolism; D009093:Mucus / Q000378:metabolism; D019158:N-Acetylneuraminic Acid / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D009439:Neuraminidase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D045246:Ornithobacterium / Q000201:enzymology* / Q000235:genetics; D011201:Poultry Diseases / Q000097:blood / Q000201:enzymology / Q000378:metabolism* / Q000382:microbiology*; D014132:Trachea / Q000378:metabolism; D014168:Transferrin / Q000378:metabolism; D014422:Turkeys; D000093422:Glycated Serum Proteins
D001798:Blood Proteins; D006023:Glycoproteins; D007074:Immunoglobulin G; D014168:Transferrin; C036137:2-deoxy-2,3-dehydro-N-acetylneuraminic acid; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid; D000093422:Glycated Serum Proteins