1
|
Affiliation(s)
- J P Ackers
- Department of Medical Parasitology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT
| |
Collapse
|
2
|
Clark CG, Alsmark UCM, Tazreiter M, Saito-Nakano Y, Ali V, Marion S, Weber C, Mukherjee C, Bruchhaus I, Tannich E, Leippe M, Sicheritz-Ponten T, Foster PG, Samuelson J, Noël CJ, Hirt RP, Embley TM, Gilchrist CA, Mann BJ, Singh U, Ackers JP, Bhattacharya S, Bhattacharya A, Lohia A, Guillén N, Duchêne M, Nozaki T, Hall N. Structure and content of the Entamoeba histolytica genome. Adv Parasitol 2008; 65:51-190. [PMID: 18063096 DOI: 10.1016/s0065-308x(07)65002-7] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The intestinal parasite Entamoeba histolytica is one of the first protists for which a draft genome sequence has been published. Although the genome is still incomplete, it is unlikely that many genes are missing from the list of those already identified. In this chapter we summarise the features of the genome as they are currently understood and provide previously unpublished analyses of many of the genes.
Collapse
Affiliation(s)
- C G Clark
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
3
|
Abstract
Invasive amoebiasis is the result of infection of Entamoeba histolytica. The closely related Entamoeba dispar can colonize the human gut but does not cause invasive disease. In this study, E. dispar was analysed for the presence of the lipophosphoglycan-like (LPG) glycoconjugate known to be present on the cell surface of E. histolytica. E. dispar cells were radio-isotope labelled with [3H]galactose or [3H]inositol. The acidic glycoconjugates were extracted and analysed by hydrophobic chromatography over phenyl-Sepharose and by sodium dodecyl sulphate polyacrylamide gel electrophoresis. No LPG-like molecules could be identified in E. dispar in contrast to E. histolytica, suggesting that these molecules may be absent in the non-pathogenic species.
Collapse
Affiliation(s)
- A Bhattacharya
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.
| | | | | | | |
Collapse
|
4
|
Bouma MJ, Snowdon D, Fairlamb AH, Ackers JP. Activity of disulfiram (bis(diethylthiocarbamoyl)disulphide) and ditiocarb (diethyldithiocarbamate) against metronidazole-sensitive and -resistant Trichomonas vaginalis and Tritrichomonas foetus. J Antimicrob Chemother 1998; 42:817-20. [PMID: 10052908 DOI: 10.1093/jac/42.6.817] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Clinical resistance of Trichomonas vaginalis to metronidazole is best correlated with MIC values measured under aerobic conditions. Under these conditions both disulfiram (bis(diethylthiocarbamoyl)disulphide), and its first mammalian metabolite, ditiocarb (diethyldithiocarbamate), showed high levels of activity against metronidazole-sensitive (disulfiram MIC, 0.1-0.7 microM; ditiocarb MIC, 0.3-9 microM) and -resistant (MICs 0.2-1.3 microM and 1.2-9 microM respectively) isolates. Tritrichomonas foetus was also sensitive-the MICs for seven metronidazole-sensitive isolates were 0.1-1.0 microM for disulfiram and 1.0-6.9 microM for ditiocarb; those for two highly metronidazole-resistant strains were 0.3-1.3 microM and 0.6-6 microM respectively. Under anerobic conditions most strains became highly resistant to both compounds. Surprisingly, disulfiram was consistently more active than ditiocarb.
Collapse
Affiliation(s)
- M J Bouma
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, UK
| | | | | | | |
Collapse
|
5
|
Abstract
Detergent lysates of Entamoeba histolytica trophozoites contained high levels of beta-N acetyl-D-glucosaminidase, beta-N acetyl-D-galactosaminidase and alpha-D-galactosidase activity, and lower but significant levels of five other glycosidases. Although these activities should have been capable of largely degrading the oligosaccharide side-chains of human colonic mucin, in fact only about one third of high MW mucin was degraded in 72 h and trypsin alone produced a similar effect. There was no evidence that these glycosidases were excreted and we conclude that they are unlikely to represent significant virulence factors for E. histolytica.
Collapse
Affiliation(s)
- W M Spice
- Department of Medical Parasitology, London School of Hygiene and Tropical Medicine, UK
| | | |
Collapse
|
6
|
Pillai DR, Britten D, Ackers JP, Ravdin JI, Kain KC. A gene homologous to hgl2 of Entamoeba histolytica is present and expressed in Entamoeba dispar. Mol Biochem Parasitol 1997; 87:101-5. [PMID: 9233678 DOI: 10.1016/s0166-6851(97)00047-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- D R Pillai
- Department of Medicine, The Toronto Hospital and The University of Toronto, ON, Canada
| | | | | | | | | |
Collapse
|
7
|
Britten D, Wilson SM, McNerney R, Moody AH, Chiodini PL, Ackers JP. An improved colorimetric PCR-based method for detection and differentiation of Entamoeba histolytica and Entamoeba dispar in feces. J Clin Microbiol 1997; 35:1108-11. [PMID: 9114390 PMCID: PMC232712 DOI: 10.1128/jcm.35.5.1108-1111.1997] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The epidemiological implications of the recent separation of "Entamoeba histolytica" into two separate species, pathogenic E. histolytica sensu stricto and commensal E. dispar, will not become apparent without methods of distinguishing between them which are applicable to large numbers of specimens. We have modified a PCR-based method to produce such a technique which may be completed in 1 day while still identifying 10(-1) E. histolytica and 1 to 10 E. dispar trophozoites per g of feces when present separately and 10 E. histolytica and 100 E. dispar trophozoites per g in the presence of 10(6) trophozoites per g of the other species. Applied to fecal specimens from 18 patients from which E. histolytica or E. dispar had been grown and identified to the species level by hexokinase isoenzyme analysis, the method in every case yielded the correct result. Positive and negative results are easily distinguished by eye, and we are now applying this technique to a large-scale epidemiological study of amebiasis in the eastern Mediterranean region.
Collapse
Affiliation(s)
- D Britten
- Department of Medical Parasitology, London School of Hygiene and Tropical Medicine, United Kingdom
| | | | | | | | | | | |
Collapse
|
8
|
Ackers JP. Gut Coccidia--Isospora, Cryptosporidium, Cyclospora and Sarcocystis. Semin Gastrointest Dis 1997; 8:33-44. [PMID: 9000500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The gut Coccidia are members of a large, varied, and exclusively intracellular group of protozoan parasites, four species of which (Isospora, Cryptosporidium, Cyclospora, and Sarcocystis) are human pathogens. The first three, but particularly Cryptosporidium parvum, have moved from medical curiosities to major problems with the coming of the acquired immunodeficiency syndrome (AIDS) epidemic, but are now known to also cause disease in the immunocompetent patient. They are easy to acquire and difficult to remove from the environment and, in the case of cryptosporidiosis, impossible to treat properly. Further research into many aspects of the biology of these organisms is urgently needed.
Collapse
Affiliation(s)
- J P Ackers
- Department of Medical Parasitology, London School of Hygiene & Tropical Medicine, UK
| |
Collapse
|
9
|
Britten D, Wilson SM, McNerney R, Moody AH, Chiodini PL, Ackers JP. Detection and differentiation of Entamoeba histolytica and E. dispar using an improved colorimetric polymerase chain reaction method. Arch Med Res 1997; 28 Spec No:279-81. [PMID: 9033101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- D Britten
- Department of Medical Parasitology, London School of Hygiene & Tropical Medicine, UK
| | | | | | | | | | | |
Collapse
|
10
|
Pillai DR, Britten D, Ackers JP, Ravdin JI, Kain KC. The sequence of a highly homologous gene to hgl2* of Entamoeba histolytica that is present and expressed in E.dispar. Arch Med Res 1997; 28 Spec No:19-20. [PMID: 9032997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- D R Pillai
- Institute of Medical Science, University of Toronto, ON, Canada
| | | | | | | | | |
Collapse
|
11
|
Gilchrist CA, Streets HL, Ackers JP, Hall R. PCR-based quantitation of transfected luciferase DNA: evaluation using an Entamoeba histolytica reporter construct. Biotechniques 1996; 20:764, 768, 770 passim. [PMID: 8723913 DOI: 10.2144/96205bm06] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
|
12
|
Odongo-Aginya EI, Taylor MG, Sturrock RF, Ackers JP, Doehring E. Field evaluation of an improved Kato-Katz thick smear technique for quantitative determination of helminth eggs in faeces. Trop Med Parasitol 1995; 46:275-7. [PMID: 8826110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A new method for the quantification of helminth eggs in faeces was developed, in which 7.5% nigrosin in 10% formaldehyde mixed with 5% eosin yellow in 10% formaldehyde was substituted for the malachite green solution used in the standard Kato-Katz method. This modification revealed the eggs of parasites like Schistosoma mansoni, Ascaris lumbricoides, Trichuris trichiura and hookworms distinctly. The slides made with this new technique could be accurately read within one hour. Faecal smears from 100 pupils in Kigungu, Entebbe, Uganda, were studied with both methods. The egg counts of S. mansoni, A. lumbricoides and T. trichiura by both methods were equal. The modified method, however, showed significantly higher hookworm egg counts (p < 0.001). Hookworm eggs were equal one hour after preparation of the slides as 16 hours after preparation. The intensity of infection detected was higher with the modified method for both S. mansoni and hookworms.
Collapse
|
13
|
Abstract
We have identified an unusual 0.55-kb DNA repeat element specific to Entamoeba histolytica (Eh) which we call interspersed element (IE). The IE is a common feature in independently isolated genomic and cDNA fragments. Hybridization of labeled IE sequences to trophozoite DNA, RNA and first-strand cDNA prepared from poly(A)-enriched mRNA indicate that the IE are reiterated about 500 times per Eh trophozoite and that one or more can be found as RNA transcripts. These features and the degree of conservation of IE suggest a possible role for these sequences.
Collapse
Affiliation(s)
- J Cruz-Reyes
- Department of Medical Parasitology, London School of Hygiene and Tropical Medicine, UK
| | | | | | | |
Collapse
|
14
|
Gilchrist CA, Streets HL, Ackers JP, Hall R. Transient expression of luciferase in Entamoeba histolytica driven by the ferredoxin gene 5' and 3' regions. Mol Biochem Parasitol 1995; 74:1-10. [PMID: 8719240 DOI: 10.1016/0166-6851(95)02474-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We have successfully transfected Entamoeba histolytica trophozoites with constructs containing ferredoxin sequences fused to the reporter gene luciferase. We have determined the conditions and parameters necessary to maximise transient luciferase expression in our system. Our optimal construct gave values of 268 x 10(3) relative light units per second (RLU s-1) when assayed representing a stimulation of 18,000-fold over the control vector. Comparison of differing constructs allowed us to conclude that the 5' and 3' ferredoxin sequences are both necessary for optimal luciferase expression from our vectors. Transcriptional initiation occurs within the consensus sequence ATTCA in both construct and chromosomal ferredoxin promoters.
Collapse
|
15
|
Sehgal R, Abd-Alla M, Moody AH, Chiodini PL, Ackers JP. Comparison of two media for the isolation and short-term culture of Entamoeba histolytica and E. dispar. Trans R Soc Trop Med Hyg 1995; 89:394. [PMID: 7570875 DOI: 10.1016/0035-9203(95)90023-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- R Sehgal
- Department of Clinical Parasitology, Hospital for Tropical Diseases, London, UK
| | | | | | | | | |
Collapse
|
16
|
|
17
|
al-Tukhi MH, Ackers JP, al-Ahdal MN, Taha MA, Peters W. ELISA for detection of anti-Giardia specific IgM: response in serum. J Trop Med Hyg 1993; 96:333-6. [PMID: 8254709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Infection with Giardia lamblia (G. duodenalis, G. intestinalis) is common all over the world, especially in children. Traditional diagnosis by faecal microscopy has only moderate sensitivity; serological tests, although not always positive, are acceptable to patients and useful in epidemiological studies. We show here that serum IgM separated by column chromatography and assayed by an indirect ELISA test can be a useful tool for the diagnosis of giardiasis. One hundred and thirty-nine positive sera (based on a single faecal examination), and 97 negative serum samples from Riyadh, Saudi Arabia, were examined. Taking positive results as being 2 s.d. above the mean of the controls, there were 117 positive results among the microscopically negative controls (3% false positives). The sensitivity of the test was 84% and the specificity 97%; the predictive value of a positive result is 97.5% and of a negative one 81%.
Collapse
|
18
|
Abstract
Gelatin SDS- polyacrylamide gel electrophoresis was used to compare proteinase banding patterns under reducing conditions from whole cell lysates of four axenic and four xenic pathogenic strains of Entamoeba histolytica. All strains shared major bands in the 34 and 66-68 kDa regions, whereas only the axenic strains produced major bands at 26, 28, 30 and 45 kDa. One axenic strain, NIH 200, when reassociated with mixed bacterial flora, reverted to an electrophoretic banding pattern characteristic of other xenic strains. These results suggest that the 26-30 kDa and 45 kDa proteinases of E. histolytica are induced by bacterial starvation while others are constitutively expressed. It is also proposed that the axenic bands of 45 and 34 kDa represent respectively, the reduced forms of the 56 and 40 kDa bands reported elsewhere under non-reducing conditions.
Collapse
Affiliation(s)
- W M Spice
- Department of Medical Parasitology, London School of Hygiene and Tropical Medicine, U.K
| | | |
Collapse
|
19
|
Spice WM, Cruz-Reyes JA, Ackers JP. Molecular and cell biology of opportunistic infections in AIDS. Entamoeba histolytica. Mol Cell Biol Hum Dis Ser 1993; 2:95-137. [PMID: 8261181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Affiliation(s)
- W M Spice
- Department of Medical Parasitology, London School of Hygiene and Tropical Medicine, UK
| | | | | |
Collapse
|
20
|
al-Tukhi MH, Ackers JP, al-Ahdal MN, Peters W. Enzyme-linked immunosorbent assay for the detection of anti-Giardia specific immunoglobulin G in filter paper blood samples. Trans R Soc Trop Med Hyg 1993; 87:36-8. [PMID: 8465391 DOI: 10.1016/0035-9203(93)90412-j] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Conventional diagnosis of infection with Giardia duodenalis is by faecal examination but the sensitivity of a single examination is low. Serological tests, although not always positive, are more acceptable to patients and are useful in determining the prevalence of giardiasis in large populations. We show here that blood collected on filter paper and dried provides an excellent source of material for enzyme-linked immunosorbent assays; using samples from a group of 88 stool-negative and 45 positive patients, the optimum results were obtained by taking the control mean optical density plus one standard deviation as the negative/positive cut-off value. The sensitivity was 91% (2/45 false negatives), and the specificity 95% (4/88 false positives). This method should be particularly useful for large-scale surveys in developing countries or wherever serological testing is done in central laboratories.
Collapse
|
21
|
Abstract
After more than 70 years of intermittent debate over the true relationship between the 'pathogenic' and 'non-pathogenic' forms of Entamoeba histolytica, the application of molecular biology has finally yielded an unambiguous answer: these are not interconvertible phenotypes of the same parasite, a kind of unicellular Jekyll and Hyde, but two quite distinct genetic entities that just happen to look the same. But given the overwhelming evidence now available from gene sequences, pointing to an evolutionary divergence some tens of millions of years ago, why is it that certain eminent workers in the field are still claiming that, at least in vitro, conversion between the two phenotypes can take place? In this article Bill Spice and John Ackers review recent developments in the molecular biology of E. histolytica and assess the continuing controversy over the status of this enigmatic parasite.
Collapse
Affiliation(s)
- W M Spice
- Department of Medical Parasitology, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | | |
Collapse
|
22
|
Cruz-Reyes JA, Spice WM, Rehman T, Gisborne E, Ackers JP. Ribosomal DNA sequences in the differentiation of pathogenic and non-pathogenic isolates of Entamoeba histolytica. Parasitology 1992; 104 ( Pt 2):239-46. [PMID: 1594290 DOI: 10.1017/s0031182000061679] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Recombinant ribosomal DNA sequences were amplified by PCR and used as probes to perform a fingerprint analysis of total DNA from different Entamoeba histolytica isolates. RFLPs obtained with one of the probes, R-1, support previous proposals that pathogenic and non-pathogenic E. histolytica are closely related, yet genotypically distinct. Another probe, R-2, while not distinguishing between the two forms of E. hystolytica, was able to differentiate between them and E. moshkovskii, which has morphologically identical cysts and trophozoites. A third probe, BR-1, identified strain-specific RFLPs.
Collapse
Affiliation(s)
- J A Cruz-Reyes
- Department of Medical Parasitology, London School of Hygiene and Tropical Medicine
| | | | | | | | | |
Collapse
|
23
|
Affiliation(s)
- W M Spice
- Department of Medical Parasitology, London School of Hygiene and Tropical Medicine, UK
| | | |
Collapse
|
24
|
Bracha R, Diamond LS, Ackers JP, Burchard GD, Mirelman D. Differentiation of clinical isolates of Entamoeba histolytica by using specific DNA probes. J Clin Microbiol 1990; 28:680-4. [PMID: 2332466 PMCID: PMC267776 DOI: 10.1128/jcm.28.4.680-684.1990] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Most individuals infected with Entamoeba histolytica are reported to be clinically asymptomatic. On the basis of the electrophoretic migration of hexokinase and phosphoglucomutase isoenzymes, two groups of E. histolytica isolates have been classified. Those derived from symptomatic cases were found to have fast-migrating hexokinase bands and were labeled pathogenic. The others, isolated from cyst passers, had (in most cases) slow-migrating bands and were called nonpathogenic. Differences between these two groups of E. histolytica were found recently at the DNA level. Two sets of different DNA probes derived from tandemly repeated sequences present in extrachromosomal circular DNA elements in each group of E. histolytica were characterized. Using these probes with procedures for direct hybridization of trophozoites on nylon membranes, we could correctly correlate hexokinase electromobility with the DNA hybridization signal of 81 different isolates of E. histolytica. The advantages of using DNA probes lie in their sensitivity (fewer than 200 trophozoites can be detected) and specificity. The probes hybridized only with amebae from the E. histolytica species and not with other enteric protozoa and can be useful as a diagnostic tool.
Collapse
Affiliation(s)
- R Bracha
- Department of Biophysics, Weizmann Institute of Science, Rehovot, Israel
| | | | | | | | | |
Collapse
|
25
|
Carney JA, Unadkat P, Yule A, Rajakumar R, Lacey CJ, Ackers JP. New rapid latex agglutination test for diagnosing Trichomonas vaginalis infection. J Clin Pathol 1988; 41:806-8. [PMID: 3045161 PMCID: PMC1141592 DOI: 10.1136/jcp.41.7.806] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A newly developed latex agglutination test for Trichomonas vaginalis infection was compared for sensitivity, specificity, efficiency, and positive and negative predictive values with microscopy, culture, and an enzyme linked immunosorbent assay (ELISA) in the diagnosis of 395 women attending a genitourinary medicine clinic. T vaginalis infection was diagnosed in 42 (11%) women. The sensitivities of both the latex agglutination test and the ELISA were 95% compared with 74% for microscopy and 76% for culture. The latex test was specific and showed no cross reaction with a wide range of other genital tract infections. The latex agglutination test can detect antigen in both soluble and insoluble forms, and as it is simple to perform, can be undertaken during routine examination without recourse to special equipment or training. Further evaluation is required.
Collapse
Affiliation(s)
- J A Carney
- Mercia Diagnostics Ltd, Guildford, Surrey
| | | | | | | | | | | |
Collapse
|
26
|
Abstract
Entamoeba histolytica can act as a harmless commensal organism in the lumen of the large intestine, or can cause invasive amoebiasis. Some workers have suggested that there are two distinct subspecies of this organism, and that only one of these is associated with invasive disease. Present isoenzyme tests to identify the subspecies take several days to analyse: we report a technique that uses immunofluorescence with monoclonal antibodies, takes two days to perform, and may, therefore, assist in the clinical management of patients infected with this organism.
Collapse
Affiliation(s)
- W D Strachan
- Department of Medical Protozoology, London School of Hygiene and Tropical Medicine
| | | | | | | | | |
Collapse
|
27
|
Abstract
An enzyme immunoassay (EIA) was developed for the detection of Trichomonas vaginalis antigen in vaginal swabs. Four hundred and eighty two women attending a sexually transmitted disease (STD) clinic were tested; 44 (9.1%) were positive by culture, 32 (6.6%) were positive by wet film examination, and 54 (11.2%) were considered to be positive for trichomonal antigen by EIA. Taking culture as the reference method, the EIA had a sensitivity of 93.2% and a specificity of 97.5%. The predictive value of a positive test was 82% and that of a negative test was 99.3%.
Collapse
|
28
|
Street DA, Wells C, Taylor-Robinson D, Ackers JP. Interaction between Trichomonas vaginalis and other pathogenic micro-organisms of the human genital tract. Br J Vener Dis 1984; 60:31-8. [PMID: 6421451 PMCID: PMC1046266 DOI: 10.1136/sti.60.1.31] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Trichomonas vaginalis organisms were mixed with suspensions of Neisseria gonorrhoeae, Mycoplasma hominis or Chlamydia trachomatis to allow ingestion of these micro-organisms by the trichomonads. Culture studies indicated that gonococci and mycoplasmas were ingested and that the number of intracellular viable organisms decreased rapidly, most gonococci being killed within six hours and all mycoplasmas within three hours. Electron microscopy revealed phagocytic uptake and destruction of these two micro-organisms within the trichomonads, gonococcal degradation being associated with lysosomal enzyme activity. There was no evidence from cultural or electron microscopy studies that C trachomatis organisms persisted in mixed culture with T vaginalis.
Collapse
|
29
|
|
30
|
Street DA, Taylor-Robinson D, Ackers JP, Hanna NF, McMillan A. Evaluation of an enzyme-linked immunosorbent assay for the detection of antibody to Trichomonas vaginalis in sera and vaginal secretions. Br J Vener Dis 1982; 58:330-3. [PMID: 6982095 PMCID: PMC1046087 DOI: 10.1136/sti.58.5.330] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Using a whole-cell antigen antibody to Trichomonas vaginalis was measured by an enzyme-linked immunosorbent assay (ELISA). IgG antibody was found in sera from only three of 99 children under 12 years of age. In contrast, serum IgG or IgM antibody or both were detected in 80.4% of women who had vaginal trichomoniasis and in 13.7% of uninfected women. Although antibody was found in cervical and vaginal secretions, the correlation between current infection and the presence of antibody was poorer than found between circulating antibody and infection. IgG or IgA antibody or both was detected in the secretions of 73.2% and 41% of infected and uninfected women respectively. This may be accounted for, at least partly, by previous infections since antibody, circulating or local, was found most often in women who had a history of trichomoniasis. There was no indication that some other vaginal micro-organism stimulated antibody directed against T vaginalis.
Collapse
|
31
|
Abstract
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.
Collapse
|
32
|
Abstract
Urine samples were collected from 248 men, 21 of whom were known contacts of women infected with Trichomonas vaginalis. This organism was cultured from only three of the 21 specimens from patients in the contact group. The cultural technique was shown to be capable of reliably detecting small numbers of organisms under practical conditions; it appears, therefore, that most male contacts shed relatively few trichomonads and that the infective dose for women must be correspondingly small.
Collapse
|
33
|
|
34
|
Ackers JP, Catterall RD, Lumsden WH, McMillan A. Absence of detectable local antibody in genitourinary tract secretions of male contacts of women infected with Trichomonas vaginalis. Br J Vener Dis 1978; 54:168-71. [PMID: 306858 PMCID: PMC1045483 DOI: 10.1136/sti.54.3.168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Samples of semen and urine were obtained from 37 male contacts of women with proved Trichomonas vaginalis infection; on culture, eight (22%) of the men were shown to harbour the parasite. However, significant amounts of antitrichomonal antibody were found in only two of these samples, and the amounts present were very small. A further 10 samples were tested but none was found to contain antibody. The asymptomatic nature and low parasite numbers commonly described in infections in men is thus unlikely to be due to a vigorous local immune response.
Collapse
|
35
|
Ackers JP, Lumsden WH, Catterall RD, Coyle R. Antitrichomonal antibody in the vaginal secretions of women infected with T. vaginalis. Br J Vener Dis 1975; 51:319-23. [PMID: 1081423 PMCID: PMC1045170 DOI: 10.1136/sti.51.5.319] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Vaginal secretions from 508 women were examined for evidence of infection by Trichomonas vaginalis, and for antibodies directed against this organism; 42 women (8-3 per cent.) were found to be infected. Secretions from 29 of these women were assayed and antibody apparently directed against T. vaginalis was found in 22 (76 per cent.) of them. Eight out of nineteen secretions (42 per cent.) from apparently uninfected women also contained antibody. Amongst the infected women, no correlation could be found between the presence or absence of antibody and the degree of inflammation, duration of symptoms, use of oral contraceptives, or additional sexually-transmitted disease; there was, however, a slight suggestion that low parasite counts in the vaginal secretions were associated with the presence of antitrichomonal antibody.
Collapse
|
36
|
Dolby JM, Ackers JP. Taxonomic distribution of the antigen eliciting bactericidal antibody for Bordetella pertussis. J Gen Microbiol 1975; 87:239-44. [PMID: 49392 DOI: 10.1099/00221287-87-2-239] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Strains of Bordetella pertussis varied in their ability to elicit (in mice) an antibody bactericidal for an antiserum-sensitive strain of B. pertussis, although antibody was usually detectable after only one injection. High titres were produced by a course of seven injections with all strains of B. pertussis tested (six of phase I and three of phase IV) but not with three strains of other Bordetella species nor with two unrelated organisms, a finding of possible taxonomic value. Preliminary investigations have not revealed whether strain vaiations are due to quantitative or qualitative differences in either the bacterial lipopolysaccharide or the carrier protein necessary for antibody production, or whether they may be due to differences in heat lability of 'bactericidal antigen'.
Collapse
|
37
|
Ackers JP, Dolby JM. The antigen of Bordetella pertussis that induces bactericidal antibody and its relationship to protection of mice. J Gen Microbiol 1972; 70:371-82. [PMID: 4338965 DOI: 10.1099/00221287-70-2-371] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
38
|
Abstract
1. Synthesis of N-iodoacetyl-d-glucosamine and its N-iodo[1,2-(14)C(2)]acetyl form has been achieved from the tetra-O-acetyl amino sugar and iodoacetic acid in the presence of dicyclohexylcarbodi-imide followed by catalytic deacetylation. 2. N-Iodoacetylglucosamine (up to 0.1mm) linearly inhibits uptake (up to 1min) of methyl alpha-d-glucoside by Escherichia coli ML308 and K12. Uptake of methyl beta-d-thiogalactoside and glycerol is also inhibited. 3. Growth of the organism (strain ML308) on glucose, succinate and glycerol is strongly inhibited by the iodoacetyl compound. The inhibition is relieved by N-acetylglucosamine. 4. The inhibitor has multiple effects, some of which are considered to be intracellular. 5. A separate transport pathway exists for N-acetylglucosamine by means of which the iodoacetyl analogue may enter the cell.
Collapse
|