Inhibition of extension outgrowth in differentiating rat C6 glioma cells by chlorpyrifos and chlorpyrifos oxon: effects on microtubule proteins.

The aim of this work was to assess the toxic effects of the phosphorothionate insecticide chlorpyrifos (CPF) and its major in vivo metabolite chlorpyrifos oxon (CPO) on differentiating rat C6 glioma cells. At sublethal concentrations (1-10 microM), both compounds were able to inhibit the development of extensions from C6 cells induced to differentiate by sodium butyrate. Western blot analysis of C6 cell lysates revealed that 4 h exposure to CPF was associated with decreased levels of the cytoskeletal protein MAP1B compared to controls, whereas the levels of the cytoskeletal proteins tubulin and MAP2c were not significantly affected. Western blot analysis of extracts of cells treated with CPO showed a significant, concentration-dependent decrease in the levels of tubulin after 24 h. MAP-1B levels were also significantly decreased. The above changes were not temporally related to acetylcholinesterase (AChE) inhibition. These results suggest that both CPF and CPO can exert toxic effects directly on glial cell differentiation and that the latter compound has a potent effect on the microtubule network.

Detection of Mycoplasma synoviae in clinically normal pheasants.

Mycoplasma synoviae was isolated from the tracheas of seven clinically normal pheasants found in the vicinity of a chicken farm infected with M synoviae, but not from 120 pheasants and partridges with respiratory disease. When specimens were examined by the polymerase chain reaction only two additional pheasants infected with M synoviae were identified, one healthy and one diseased.

Mycoplasmas and respiratory disease in pheasants and partridges.

Pheasants and partridges with signs of upper respiratory disease were cultured for mycoplasmas and were also examined for Mycoplasma gallisepticum and Mycoplasma synoviae using commercial polymerase chain reaction (PCR) kits. Sixty-two incidents of disease were investigated in pheasants and 12 in partridges. M. gallisepticum was detected by culture in only four and three incidents in pheasants and partridges, respectively, but with PCR a further 15 M. gallisepticum-positive incidents were detected in pheasants and another five in partridges. Several fast-growing Mycoplasma species, in particular Mycoplasma glycophilum, Mycoplasma gallinaceum and Mycoplasma pullorum, were isolated frequently and were thought to be impeding the isolation of M. gallisepticum by outgrowing it. Samples yielding M. gallisepticum isolates contained significantly fewer "contaminating" species and were exclusively from specimens submitted as whole heads rather than as swabs or as cultures from other laboratories. M. synoviae was not isolated and was detected in only one specimen by PCR.

Identification of Mycoplasma iowae by colony immunoblotting utilizing monoclonal antibodies.

The utility of monoclonal antibody Mab-2C in identification of Mycoplasma iowae (MI) by colony immunoblotting technique was explored. Colony immunoblots of reference MI strains, field isolates, and mycoplasmas recovered from experimentally inoculated turkey embryos were probed with Mab-2C. The monoclonal antibody identified colonies of all the MI isolates tested and did not cross-react with colonies of M. gallisepticum, M. synoviae, or M. meleagridis. In western immunoblots of 22 MI field isolates, Mab-2C showed immunoreactivity with an antigen of approximately 45 kD molecular weight. No phenotypic variation of the epitope recognized by Mab-2C was observed in colony immunoblots of MI colonies. The monoclonal antibody reported here can be used for identification of MI colonies by a simple and rapid colony immunoblot method.

In vitro evaluation of various antimicrobials against Mycoplasma gallisepticum and Mycoplasma synoviae by the micro-broth method, and comparison with a commercially-prepared test system.

The efficacy of danofloxacin, a new quinolone antimicrobial agent, was tested in vitro by the micro-broth method with nine field strains of Mycoplasma gallisepticum (Mg) and eight of M. synoviae (Ms) and comparison was made with oxytetracycline and tylosin tartrate. The virulent S6 strain of Mg was also included for reference. All Mycoplasma strains, including a strain of Mg that was resistant to tylosin tartrate, were susceptible to danofloxacin with minimal inhibitory concentrations ranging from pound 0.008 to 0.5 microg/ml. A commercially produced test system (Sensititre), using micro-plates whose wells were predosed with antimicrobial agents and then dried, was also investigated. Results with the same three antimicrobials were in agreement with those obtained by the micro-broth method. With the exception of the tylosin resistant strain, the Mg strains were more susceptible to erythromycin than the Ms strains. Conversely, Ms strains were susceptible to apramycin, while the Mg strains appeared to be resistant.

Investigations into the survival of Mycoplasma gallisepticum, Mycoplasma synoviae and Mycoplasma iowae on materials found in the poultry house environment.

Following preliminary experiments to determine suitable methods for studying mycoplasma survival, suspensions of Mycoplasma gallisepticum (four strains), Mycoplasma synoviae (two strains) or Mycoplasma iowae (two strains) were seeded onto replicate samples of cotton, rubber, straw, shavings, timber, food, feathers and human hair. The organisms were also seeded onto human skin, ear and nasal mucosa. All samples were cultured for viability after 4, 8, 12 and 24 h, and then daily up to 6 days. The identity of recovered mycoplasmas was confirmed by indirect immunofluorescence. All three Mycoplasma species survived for the longest time on feathers with M. gallisepticum surviving between 2 and 4 days and M. synoviae 2 to 3 days. The type strain of M. iowae remained viable for 5 days on feathers, while the field strain was still viable at the end of the 6-day experiment. This strain also survived for at least 6 days on human hair and several other materials. M. gallisepticum survived on human hair up to 3 days and one recent field isolate also survived in the nose for 24 h. Survival times of the organisms were generally less on other materials although M. gallisepticum could be isolated from straw, cotton and rubber samples after 2 days.

Mycoplasma imitans sp. nov. is related to Mycoplasma gallisepticum and found in birds.

A mycoplasma designated strain 4229T (T = type strain) was isolated in 1984 from the turbinate of a duck in France, and similar strains were isolated from geese in France and from a partridge in England. All of these strains were originally identified as Mycoplasma gallisepticum by immunofluorescence and growth inhibition tests, but subsequent serological and molecular studies indicated only a partial relationship to this species and DNA-DNA hybridization studies revealed only approximately 40 to 46% genetic homology with M. gallisepticum PG31T. In this study morphological, cultural, and physical investigations were carried out on strain 4229T and partridge strain B2/85, after we first demonstrated the similarity between these organisms by performing a restriction enzyme analysis of their DNAs. Both strains had phenotypic properties very similar to M. gallisepticum properties, including the presence of an attachment organelle. As a result of these investigations, the organisms were assigned to the class Mollicutes, the order Mycoplasmatales, and the genus Mycoplasma. They fermented glucose, reduced triphenyl tetrazolium chloride aerobically and anaerobically, and exhibited hemadsorption and hemagglutination, but other biochemical tests were negative. Apart from a serological cross-reaction with M. gallisepticum, these organisms exhibited no significant relationship with any previously described Mycoplasma species as determined by growth inhibition or immunofluorescence tests or with a number of additional serovars and unclassified avian strains. This Mycoplasma taxon therefore appears to be a new species, for which we propose the name Mycoplasma imitans. The type strain is strain 4229 (= NCTC 11733 = ATCC 51306).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of Baytril, Tylosin and Tiamulin on avian mycoplasmas.

The minimum inhibitory concentration (MIC) of Baytril, Tylosin and Tiamulin for strains of Mycoplasma gallisepticum (MG) M. synoviae (MS), M. meleagridis (MM) and M. iowae (MI) and serovars were compared. In general the lowest MIC for MG, MS and MI was obtained with Baytril, while for MM both Baytril and Tiamulin gave the lowest MICs. Protection against mortality was best attained with Baytril for broiler chicks and poults but against prevention of growth depression Baytril was best for broiler chicks whilst Baytril and Tylosin were equally effective in poults. MG was recovered from fewer birds following treatment with Tiamulin and then Baytril in that order. Baytril also had a suppressive effect on the natural infection of MI in poults. Fewer poults showed rapid serum agglutination reactions to MG antigen following Baytril treatment than with the other antimicrobials. The tolerance of turkey embryos for Baytril was between 1 and 2 mg/ egg. Baytril reduced MG infection of turkey embryos.