The mode of action of a novel 18-membered macrolide, virustomycin A (AM-2604 A), on Trichomonas foetus.
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The mode of action of virustomycin A, a novel 18-membered macrolide, on Trichomonas foetus was investigated. The antibiotic inhibited the biosynthesis of RNA, DNA and protein in the organism. The inhibition of RNA biosynthesis was the most severe. Virustomycin A repressed the incorporation of [3H]uridine into both acid-soluble and insoluble fractions, whereas actinomycin D inhibited the incorporation of [3H]uridine into acid-insoluble fraction alone. Furthermore, it was found that virustomycin A interfered with nucleotide formation from uridine and adenosine but not with their transport to the cells. On the other hand, the antibiotic did not inhibit the activities of uridine kinase and uracil phosphoribosyltransferase in a cell-free extract from the organism. These data suggest that the antibiotic interferes with the formation of phosphate donor(s) (possibly ATP-forming system) of the organism. (+info)
Isoenzyme characterisation of Trichomonas vaginalis.
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Clones of 32 strains of Trichomonas vaginalis isolated from patients attending a venereal diseases clinic were compared among themselves and with authentic Pentatrichomonas hominis on the basis of their isoenzyme patterns for eight enzymes by thin-layer starch-gel electrophoresis. The enzymes examined were: glucose phosphate isomerase (GPI); phosphoglucomutase (PGM); malic enzyme (NADP+) (ME); hexokinase (HK); malate dehydrogenase (NAD+) (MDH); glucose-6-phosphate dehydrogenase (G6PD); aldolase (ALD); and lactate dehydrogenase (LDH). From the isoenzyme patterns of four enzymes (LDH, MDH, HK, and GPI) the strains of T vaginalis could be divided clearly into five groups. PGM showed differences in only one strain, while two other enzyme patterns (ME and ALD) were the same for all the strains of T vaginalis tested. All isolates were clearly distinguishable from P hominis. Although G6PD patterns were not sharp some differences were evident among T vaginalis strains. (+info)
Antibody to Trichomonas vaginalis in human cervicovaginal secretions.
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Human cervicovaginal secretions were obtained from patients at the Gynecology and Obstetrics Clinics at National Taiwan University Hospital and Cathay General Hospital, Republic of China. Among the 500 patients examined, 33 (6.6%) were infected with Trichomonas vaginalis as determined by the culture method. Secretions from 24 of the infected patients and 30 noninfected women were assayed for anti-T. vaginalis immunoglobulins by the indirect immunofluorescent antibody technique. A few serum samples from both infected and noninfected persons were also included in this study. Immunoglobulin G (IgG) antibody against T. vaginalis was detected in 17 (70.8%) secretions from the infected women. Among the 17 positive secretions, anti-parasite IgA was found in two specimens, IgE was found in three, and IgM was found in one. Of the 30 secretions, 7 (23.3%) from noninfected women also contained anti-parasite IgG. Low levels of natural anti-trichomonad IgG and IgM were detected in the sera of normal persons. Infection with T. vaginalis caused an increase in the serum IgG antibody titer. Cross-reaction between T. vaginalis and Pentatrichomonas hominis was also observed. (+info)
Mechanisms of selective toxicity of metronidazole and other nitroimidazole drugs.
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The selectively toxic effect of nitroimidazole drugs towards anaerobic bacteria and protozoa depends on a number of factors. The killing action of such drugs as metronidazole requires the reduction of the nitro group, a process which influences the rate of entry of the drug into the susceptible cell and which is determined by mechanisms involving ferredoxin-linked (or the equivalent) reactions in the cell. The reduced agent subsequently causes strand breakage of DNA, the extent of which depends on the A + T content of the DNA. Other effects of such drugs may include the possible inhibition of DNA repair mechanisms which exacerbate DNA damage, Inhibition of activity of nitroimidazoles may be caused by aminothiol radical scavengers and radioprotectors normally present in the cell or by the presence of other organisms in the environment (that is, the vagina) capable of inactivating the drugs. (+info)
Antenatal screening for candidiasis, trichomoniasis, and gonorrhoea.
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Gonorrhoea was not found to be a problem in antenatal patients. It was found in only one out of 625 women, thus confirming other British surveys which do not agree with the North American figures. Candidiasis is commoner than trichomoniasis (27.4 and 4.7 per cent. prevalence respectively) and culture of a high vaginal swab is more effective as a means of diagnosis than a cervical cytology smear. The two conditions seldom occur together. The detection rate for Candida increases with gestation, but not with age, parity, or premarital and extramarital conception. The species isolated was predominantly Candida albicans. Trichomonads are detected in culture of a high vaginal swab more often than in a cervical cytology smear. Detection does not increase with age, parity, or gestation, but does increase with premarital and extramarital conception. It is difficult to diagnose clinically the cause of vaginal discharge in a pregnant woman. (+info)
Purification and characterization of a sialic acid-specific lectin from Tritrichomonas mobilensis.
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New sialic acid-specific lectin has been isolated from culture supernatant of the protozoan Tritrichomonas mobilensis. It was purified by adsorption by erythrocytes or bovine submaxillary gland mucin (BSM)-Sepharose affinity chromatography. The T. mobilensis lectin (TML) does not require bivalent cations for activity and agglutinates all human erythrocytes. The lectin forms multimeric complexes with molecular mass 556 and 491 kDa as determined by size-exclusion chromatography. SDS/PAGE under reducing conditions disclosed a large band of 343 kDa and three bands of 246, 265 and 286 kDa which, after denaturation with urea, were split into three subunits of 56, 61 and 66 kDa; under non-reducing conditions there were two bands, of 360 and 260 kDa. Western blots performed with anti-TML monoclonal antibodies revealed bands identical with those in the silver-stained gels, suggesting homogeneity of the BSM -Sepharose-purified lectin. TML is a highly glycosylated protein with approx. 8% of N-linked glycosides found by protein-N-glycanase F treatment; the total amount of saccharides revealed by chemical deglycosylation was 20%. Haemagglutination-inhibition studies documented exclusive specificity for sialic acid (NeuAc). Both (alpha 2-->6)- and (alpha 2-->3)-linked and free NeuAc were eight times more potent inhibitors than N-glycolylneuraminic acid. The lectin does not require O-acetyl groups on NeuAc for recognition. A spectrum of mono- and oligo-saccharides other than sialic acid had no inhibitory effect at 200 mM. Anti-TML monoclonal antibodies strongly inhibited the lectin activity. TML was stable at temperatures below 4 degrees C and lyophilized with 3% (w/w) glycerol. (+info)
Contact-independent cytotoxicity of Trichomonas vaginalis.
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OBJECTIVE: To test the dependency of haemolytic and cytocidal manifestations of pathogenicity of Trichomonas vaginalis on direct contact between the target cells and the organism. TEST ORGANISM: T vaginalis strain Baltimore 42. DESIGN: Haemolysis in the presence of live T vaginalis and of its filter-sterilised metabolic products was compared. The dependence of haemolytic and cytocidal effects on retention of low pH of metabolic products of the organism was demonstrated by parallel titrations of sterile filtrates in normal saline and in phosphate buffered saline (PBS) pH 7.0. RESULTS: Near complete lysis was obtained when erythrocytes mixed with T vaginalis were incubated for 1 h at 37 degrees C in saline containing 1% glucose. The same degree of haemolysis was present in filter-sterilised glucose-saline in which the organism was incubated (1 h/37 degrees C) before erythrocytes were added and incubated under the same conditions as in the mixture with the organism. The degree of haemolysis in filtrates was dependent on retention of low pH (below 5.0) of the suspending fluid in which the organism alone was incubated. Dilution of filtrates in PBS, as opposed to normal saline, abolished or diminished the haemolytic effect. Presence of glucose (energy source) in the saline during incubation of the organism had a pronounced enhancing effect. The production of haemolytic metabolites was temperature dependent, whereas the haemolytic process per se was not. The effect was not an exclusive property of T vaginalis since it was also demonstrated with other trichomonads. The same filtrates applied to tissue culture exerted cytocidal effect strikingly similar to that observed in the haemolysis experiments. CONCLUSION: Neither haemolytic nor cytocidal effect of T vaginalis was contact-dependent. (+info)
Pulmonary eosinophilia due to Trichomonas tenax.
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A 39 year old woman was admitted with fever and an exacerbation of asthma. The chest radiograph showed extensive bilateral lung infiltrates, but transtracheal needle aspiration did not reveal any infectious organisms. The bronchoalveolar fluid lavage contained a large number of Trichomonas tenax and an increased percentage of eosinophils. Corticosteroids provided a dramatic response. Because of the relatively high frequency of colonisation of the human mouth by T tenax (about 20%), this organism should be considered in all cases of pulmonary eosinophilia. (+info)