Chronic "Candidatus Mycoplasma turicensis" infection

"Candidatus Mycoplasma turicensis" infects felids. The pathogenesis of "Candidatus M. turicensis" chronic infection is poorly understood. The goals of the present study were to (1) induce reactivation of the infection in chronic carrier cats by attempted immunosuppression, (2) identify potential tissue sequestration using real-time TaqMan® PCR and (3) monitor the humoral immune response by DnaK enzyme-linked immunosorbent assay (ELISA). Ten specified pathogen-free cats that had ostensibly recovered from experimental "Candidatus M. turicensis" infection were used: five cats (group 1) received high dose methylprednisolone (attempted immunosuppression), while five cats served as untreated controls (group 2). Besides weekly blood samples, tissue samples were collected from bone marrow, kidney, liver and salivary glands at selected time points. The cats in group 1 had significantly lower lymphocyte counts and higher blood glucose levels after methylprednisolone administration than the controls. After methylprednisolone administration one blood and three tissue samples from cats in group 1 tested PCR-positive; before the administration, only one sample was positive. All other samples tested PCR-negative. All cats stayed seropositive; the antibody levels of the cats in group 1 showed a significant transient decrease after methylprednisolone administration. This is the first study to report the presence of "Candidatus M. turicensis" in tissues of chronically infected cats and the persistence of anti-feline hemoplasma antibodies in the absence of detectable bacteremia. Methylprednisolone administration did not lead to a significant reactivation of the infection. Our results enhance the knowledge of "Candidatus M. turicensis" infection pathogenesis and are clinically relevant to the prognosis of hemoplasma-infected cats

Fate of ptaquiloside—A bracken fern toxin—In cattle

Ptaquiloside is a natural toxin present in bracken ferns (Pteridium sp.). Cattle ingesting bracken may develop bladder tumours and excrete genotoxins in meat and milk. However, the fate of ptaquiloside in cattle and the link between ptaquiloside and cattle carcinogenesis is unresolved. Here, we present the toxicokinetic profile of ptaquiloside in plasma and urine after intravenous administration of ptaquiloside and after oral administration of bracken. Administered intravenously ptaquiloside, revealed a volume of distribution of 1.3 L kg-1 with a mean residence-time of 4 hours. A large fraction of ptaquiloside was converted to non-toxic pterosin B in the blood stream. Both ptaquiloside and pterosin B were excreted in urine (up to 41% of the dose). Oral administration of ptaquiloside via bracken extract or dried ferns did not result in observations of ptaquiloside in body fluids, indicating deglycosolidation in the rumen. Pterosin B was detected in both plasma and urine after oral administration. Hence, transport of carcinogenic ptaquiloside metabolites over the rumen membrane is indicated. Pterosin B recovered from urine counted for 7% of the dose given intravenously. Heifers exposed to bracken for 7 days (2 mg ptaquiloside kg-1) developed preneoplastic lesions in the urinary bladder most likely caused by genotoxic ptaquiloside metabolites

Identification, characterization, and application of a recombinant antigen for the serological diagnosis of feline hemotropic mycoplasma infections

Bei Feliden wurden Infektionen mit den drei hämotropen Mykoplasmen (Hämoplasmen) Mycoplasma haemofelis (Mhf), ‘Candidatus Mycoplasma haemominutum’ (CMhm) und ‘Candidatus Mycoplasma turicensis’ (CMt) beschrieben. Insbesondere Mhf kann eine schwerwiegende, potentiell lebensbedrohliche hämolytische Anämie hervorrufen. Da es noch keinen serologischen Test für die Routinediagnostik feliner Hämoplasmeninfektionen gibt, war das Ziel dieser Studie, ein Mhf-Antigen (DnaK) für den Einsatz als rekombinantes Protein in solch einem Test zu identifizieren. Die Gensequenz des DnaK-Proteins wurde unter Verwendung von Konsensusprimern aus Blutproben natürlich und experimentell infizierter Katzen, sowie eines natürlich infizierten Iberischen Luchses isoliert. Das DnaK-Gen wurde anschliessend von einer E. coli- Knockout-Mutante rekombinant exprimiert und mittels Ni-Affinitäts-, Grössenausschluss- und Ionenaustauschchromatographie aufgereinigt. Die biochemische und funktionelle Charakterisierung ergab, dass Mhf-DnaK typische DnaK-Mermale aufweist: Sekundärstrukturprofil, thermische Denaturierung, ATPase- Aktivität, Hitzeschockkomplementierung. Weiterhin wurde seine Immunogenität mithilfe von Seren experimentell infizierter Katzen in Westernblot- und ELISA-Tests überprüft. Das Antigen wurde von Seren mit Mhf, CMhm und CMt infizierter Tiere erkannt, während Seren naiver Tiere nicht reagierten. Dies ist die erste Beschreibung eines vollständigen, reinen, rekombinanten Antigens feliner Hämoplasmen. In felids, three hemotropic mycoplasma species (hemoplasmas) have been described: Mycoplasma haemofelis (Mhf), ‘Candidatus Mycoplasma haemominutum’ (CMhm), and ‘Candidatus Mycoplasma turicensis’ (CMt). Particularly, Mhf may cause severe, potentially life-threatening hemolytic anemia. No routine serological assays for feline hemoplasma infections are available. Thus, the goal of this project was to identify an Mhf antigen (DnaK), to be used as a recombinant antigen in serological assays for the diagnosis of feline hemoplasma infections. The gene sequence of this protein was determined using consensus primers and blood samples from naturally and experimentally Mhf infected cats, and a naturally infected Iberian lynx (Lynx pardinus). Mhf DnaK was expressed recombinantly in an E. coli DnaK knock-out strain and purified using Ni-affinity, size exclusion, and anion exchange chromatography. It was then biochemically and functionally characterized and showed characteristics typical for DnaKs (secondary structure profile, thermal denaturation, ATPase activity, and DnaK complementation). Moreover, its immunogenicity was assessed using serum samples from experimentally hemoplasma infected cats. When the protein was applied in Western blot and enzyme-linked immunosorbent assays, it was recognized by sera from cats infected with Mhf, CMhm and CMt, respectively, but not from uninfected cats. This is the first description of a full-length purified recombinant feline hemoplasma antigen