Adaptation of the carbon metabolism of Trichomonas vaginalis to the nature and availability of the carbon source

Kuile, Benno H. ter

doi:10.1099/13500872-140-9-2503

Cited by 10 publications

(8 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2B, white bars), the LDH levels detected were below background levels (i.e., incubation of host cells under the same conditions but without the addition of parasites). This most likely results from very low or absent cytolysis, combined with the ability of T. vaginalis to scavenge and ingest proteins and other metabolites from the surrounding medium (48,49,50,51), resulting in a lower LDH readout. A similar phenomenon of LDH values below background was observed in several previous studies (52,53).…”

Section: Resultsmentioning

confidence: 99%

Trichomonas vaginalis Contact-Dependent Cytolysis of Epithelial Cells

et al. 2013

View full text Add to dashboard Cite

bTrichomonas vaginalis is an extracellular protozoan parasite that binds to the epithelium of the human urogenital tract during infection. In this study, we examined the propensities of 26 T. vaginalis strains to bind to and lyse prostate (BPH-1) and ectocervical (Ect1) epithelium and to lyse red blood cells (RBCs). We found that only three of the strains had a statistically significant preference for either BPH-1 (MSA1103) or Ect1 (LA1 and MSA1123). Overall, we observed that levels of adherence are highly variable among strains, with a 12-fold range of adherence on Ect1 cells and a 45-fold range on BPH-1 cells. Cytolysis levels displayed even greater variability, from no detectable cytolysis to 80% or 90% cytolysis of Ect1 and BPH-1, respectively. Levels of adherence and cytolysis correlate for weakly adherent/cytolytic strains, and a threshold of attachment was found to be necessary to trigger cytolysis; however, this threshold can be reached without inducing cytolysis. Furthermore, cytolysis was completely blocked when we prevented attachment of the parasites to host cells while allowing soluble factors complete access. We demonstrate that hemolysis was a rare trait, with only 4 of the 26 strains capable of lysing >20% RBCs with a 1:30 parasite/RBC ratio. Hemolysis also did not correlate with adherence to or cytolysis of either male (BPH-1)-or female (Ect1)-derived epithelial cell lines. Our results reveal that despite a broad range of pathogenic properties among different T. vaginalis strains, all strains show strict contact-dependent cytolysis. T he exclusively human-infective flagellated parasitic protistTrichomonas vaginalis is the cause of the most common nonviral sexually transmitted disease, trichomoniasis. In women, the parasite resides in the vagina and colonizes the cervix; in men, it can be found in the urogenital tract and the prostate. In 2008 alone there were an estimated 276.4 million new cases in adults between 19 and 49 years of age, with a 10-fold-higher prevalence in females than in males (1). T. vaginalis in males often goes undetected, and thus the incidence is difficult to determine. However, it has been reported that in men with infected female partners, the incidence can range from 15 to 73% (2, 3, 4, 5). Additionally, men can clear infections 3 to 12 times faster than women whether the infection is treated or not (6, 7). The percentage of men who reportedly remain asymptomatic upon T. vaginalis infection is highly variable depending on the population examined and the diagnostic technique utilized. Regardless, it is thought that a higher proportion of men than women have asymptomatic infections (4,8,9).T. vaginalis infection can cause symptoms ranging from irritation and swelling in the urogenital tract to severe complications such as cervical erosion and premature birth during pregnancy (10,11,12). Trichomoniasis is also associated with infertility in both men and women (13,14). Moreover, infections are linked to cervical cancer (15,16,17,18), benign prostate hyperplasia (19), advance...

show abstract

Section: Resultsmentioning

confidence: 99%

Trichomonas vaginalis Contact-Dependent Cytolysis of Epithelial Cells

et al. 2013

View full text Add to dashboard Cite

show abstract

“…In contrast to the often-made assumption that the initial step in a metabolic pathway controls its rate, G K is less correlated to the metabolic flux than PGI and PPi-PFK and most other enzymes. This can explain the results of experiments measuring the uptake of radiolabelled glucose, which showed that G K specific activity is not always correlated to glucose uptake (Ter Kuile, 1994b). The high degree of correlation between PPi-PFK and the consumption of glucose does not prove with certainty that this enzyme catalyses a rate-determining step.…”

Section: Flux Control By Adapting Specific Activitiesmentioning

confidence: 91%

“…Non-proportional adaptation of enzymes of the central pathway and those involved in the formation of only one or part of the end products can also lead to changes in the ratio of the end products formed. The metabolic adaptation described earlier (Ter Kuile, 1994b) may cause such non-proportional adaptation. This phenomenon was observed in the yeast Saccharomyes cerevisiae (Sierkstra e t al., 1994).…”

Section: Introductionmentioning

confidence: 87%

Metabolic adaptation of Trichomonas vaginalis to growth rate and glucose availability

Kuile

1996

Microbiology

View full text Add to dashboard Cite

The parasitic protist Trichomonas vaginalis adapted the specific activities of twelve of the enzymes involved in glucose metabolism to the growth rate an glucose availability. These changes in enzyme activities were induced by culturing T. vaginalis in chemostats with glucose, present in rate-limiting or excess concentrations, as carbon and energy source. The specific activities were measured in pelleted cells at each steady state, while metabolic end products were determined in filtered culture fluid. The specific activities were lower in cells grown on growth-rate-limiting concentrations of glucose and higher in organisms cultured in the presence of excess glucose. In both cases enzyme activities were higher at increasing growth rates. For most enzymes the difference between the highest and lowest activities was an order of magnitude. The specific activities of eleven of the enzymes were strongly correlated to each other (correlation coefficients 0.83-0.99), the exception being lactate dehydrogenase. The rates of production of the three major end products, lactate, acetate and glycerol, increased with increasing growth rates. Alanine was not formed in measurable quantities. The ratio of the end products formed was strongly influenced by the growth rates and glucose availability. The rates of formation of acetate and glycerol correlated best with the specific activities of the enzymes catalysing the final reactions of their respective pathways. This suggests that the production of acetate and glycerol is rate-limited by these final steps. In contrast, the formation of lactate did not correlate with the specific activity of lactate dehydrogenase but was determined by the rate of glucose consumption.

show abstract

“…Chemostats have been used to study prokaryotes (287), but little work has been done with eukaryotic organisms (176). The use of chemostats has an advantage over the use of batch culture for growing organisms, since investigators can create conditions that closely approximate what occurs in vivo.…”

Section: Carbohydrate and Energy Metabolismmentioning

confidence: 99%

“…The use of chemostats has an advantage over the use of batch culture for growing organisms, since investigators can create conditions that closely approximate what occurs in vivo. Studies of T. vaginalis carbohydrate metabolism show that although the parasite is not exceedingly energy efficient, it is able to adapt its metabolism according to available carbon sources (286,287). T. vaginalis has a high maintenance energy, expending up to half its carbon flow on maintaining internal homeostasis (287).…”

Section: Carbohydrate and Energy Metabolismmentioning

confidence: 99%

Clinical and Microbiological Aspects ofTrichomonas vaginalis

et al. 1998

View full text Add to dashboard Cite

SUMMARY Trichomonas vaginalis, a parasitic protozoan, is the etiologic agent of trichomoniasis, a sexually transmitted disease (STD) of worldwide importance. Trichomoniasis is the most common nonviral STD, and it is associated with many perinatal complications, male and female genitourinary tract infections, and an increased incidence of HIV transmission. Diagnosis is difficult, since the symptoms of trichomoniasis mimic those of other STDs and detection methods lack precision. Although current treatment protocols involving nitroimidazoles are curative, metronidazole resistance is on the rise, outlining the need for research into alternative antibiotics. Vaccine development has been limited by a lack of understanding of the role of the host immune response to T. vaginalis infection. The lack of a good animal model has made it difficult to conduct standardized studies in drug and vaccine development and pathogenesis. Current work on pathogenesis has focused on the host-parasite relationship, in particular the initial events required to establish infection. These studies have illustrated that the pathogenesis of T. vaginalis is indeed very complex and involves adhesion, hemolysis, and soluble factors such as cysteine proteinases and cell-detaching factor. T. vaginalis interaction with the members of the resident vaginal flora, an advanced immune evasion strategy, and certain stress responses enable the organism to survive in its changing environment. Clearly, further research and collaboration will help elucidate these pathogenic mechanisms, and with better knowledge will come improved disease control.

show abstract

Adaptation of the carbon metabolism of Trichomonas vaginalis to the nature and availability of the carbon source

Cited by 10 publications

References 17 publications

Trichomonas vaginalis Contact-Dependent Cytolysis of Epithelial Cells

Trichomonas vaginalis Contact-Dependent Cytolysis of Epithelial Cells

Metabolic adaptation of Trichomonas vaginalis to growth rate and glucose availability

Clinical and Microbiological Aspects ofTrichomonas vaginalis

Contact Info

Product

Resources

About