Nucleic Acid Metabolism in Trichomonas vaginalis

Wang, Ching C.

doi:10.1007/978-1-4612-3224-7_6

Cited by 8 publications

(10 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Excess thymidine (2 mM) produces G 1/S phase arrest in yeasts and vertebrate cells by feedback inhibition of nucleotide biosynthesis [4, 331. T. vaginalis S 1 138 and S764 cells were insensitive to excess thymidine although these cells are known to incorporate thymidine [40]. The insensitivity of T. vaginalis cells to excess thymidine is consistent with biochemical studies strongly suggesting that T. vaginalis lacks nucleotide biosynthetic pathways [40, 411. In yeasts and vertebrate cells, such pathways, including ribonucleotide reductase activity, are usually needed for the G 1/S phase transition.…”

Section: Discussionsupporting

confidence: 67%

“…The primary target of hydroxyurea is ribonucleotide reductase [ 191. T. vaginalis cells lack ribonucleotide reductase [40,421 and are incapable of reducing ribonucleotides to deoxyribonucleotides, observations that likely explain the relative insensitivity to hydroxyurea that we observed.…”

Section: Discussionmentioning

confidence: 58%

“…Nucleotide biosynthesis normally involves at least 35 separate activities [ 131. There is evidence that G. lamblia and E. histolytica, protozoa representing other early eukaryotic lineages, also lack nucleotide biosynthesis [40]. It is unknown whether these parasites import the necessary nucleotides from the host or associated flora.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Trichomonas vaginalis: Dominant G2 Period and G2 Phase Arrest in a Representative of an Early Branching Eukaryotic Lineage

Riley

Krieger

Miner

et al. 1994

J Eukaryotic Microbiology

View full text Add to dashboard Cite

Eukaryotic mitotic cell cycles have been extensively studied in yeasts and vertebrate cells but little is known about cell cycle mechanisms in early branches of the eukaryotic lineage. Trichomonas vaginalis represents one of the earliest branching eukaryotic lineages available for study. In contrast with most yeasts and vertebrate cells, the T. vaginalis G2 period was prolonged, comprising 50 to 58% of the cell population. Hydroxyurea, aphidicolin, and excess thymidine, all of which arrest yeasts and vertebrate cells at the G1/S phase boundary, had no effect on the T. vaginalis cell cycle, probably due to the known absence of synthetic pathways. The anti-microtubule mitotic inhibitors, colchicine and nocodazole, induced G2 phase synchrony. Metronidazole, a therapeutic reagent, also caused G2 phase arrest. These observations suggest that T. vaginalis is similar to yeasts and vertebrate cells in G2 and M phases, but the parasite's G1/S phase transition is distinctive. The results also suggest potentially therapeutic, anti-trichomonad activity of microtubule inhibitors such as nocodazole. The cultured parasite may prove useful as a model for the mitotic cell cycle in the absence of G1/S phase transitional activities universal in yeasts and vertebrate cells.

show abstract

Section: Discussionsupporting

confidence: 67%

Section: Discussionmentioning

confidence: 58%

See 1 more Smart Citation

Trichomonas vaginalis: Dominant G2 Period and G2 Phase Arrest in a Representative of an Early Branching Eukaryotic Lineage

Riley

Krieger

Miner

et al. 1994

J Eukaryotic Microbiology

View full text Add to dashboard Cite

show abstract

“…Our laboratory has characterized an ecto-5′-nucleotidase activity in trophozoites of T. vaginalis (Tasca et al 2003) and Trichomonas gallinae (Borges et al 2007), and ultrastructural cytochemical microscopy has shown ecto-5′-nucleotidase activity on the surface of the parasite (Tasca et al 2004). The presence of an enzyme that hydrolyzes AMP to adenosine provides the nucleoside required for parasite growth due to the lack of de novo purine nucleotide synthesis among all trichomonad species (Wang 1990;Munagala and Wang 2003).…”

Section: Introductionmentioning

confidence: 98%

Steroid hormones alter AMP hydrolysis in intact trophozoites of Trichomonas vaginalis

et al. 2009

View full text Add to dashboard Cite

Trichomonas vaginalis infection may be influenced by the vaginal concentrations of estrogens. We have investigated the effects of 17beta-estradiol and dehydroepiandrosterone sulfate (DHEAS) on the ecto-5'-nucleotidase activity in fresh clinical (VP60) and in long-term-grown (30236 ATCC) isolates of T. vaginalis. In vitro exposure to DHEAS and 17beta-estradiol did not induce any changes in adenosine monophosphate (AMP) hydrolysis in these isolates. The treatment of parasites in the presence of DHEAS (0.01-1.0 microM) for 2 h inhibited AMP hydrolysis in VP60 isolate, whereas there were no significant changes in nucleotide hydrolysis in the presence of 17beta-estradiol. DHEAS and 17beta-estradiol (0.01-1.0 microM) for 2 h inhibited AMP hydrolysis in 30236 isolate. The 12 treatment with 0.1 microM DHEAS inhibited AMP hydrolysis, whereas 17beta-estradiol did not alter the nucleotide hydrolysis in VP60 isolate. Our findings have shown that the complex effect of steroid hormones and their receptors on T. vaginalis may promote changes in ecto-5'-nucleotidase activity during exposure to these hormones.

show abstract

“…Activation of nucleotide biosynthetic pathways is a major event in the mitotic cell cycles of yeasts and vertebrate cells. However, T. vaginalis, G. lamblia, Entamoeba histolytica, and other protozoa lack nucleotide biosynthetic pathways (Wang 1990; Wang and Cheng 1984). This absence may result from parasitism, or from an earlier-evolving ability to scavenge nucleotides from external sources such as bacteria.…”

Section: Introductionmentioning

confidence: 99%

Molecular and phylogenetic analysis of PCR-amplified cyclin-dependent kinase (CDK) family sequences from representatives of the earliest available lineages of eukaryotes

Riley

Krieger

1995

J Mol Evol

View full text Add to dashboard Cite

Cyclin-dependent kinase (CDK) and cell division control (CDC2) sequences are strongly conserved among eukaryotes and may complement the use of other sequence families in eukaryotic phylogenetic inference. We synthesized degenerate PCR primers to amplify the catalytic region of CDK homologs in representatives of the earliest available lineages of eukaryotes. CDK family sequence-based, maximum-likelihood distance measurements with neighbor-joining, and Fitch-Margoliash least-squares analyses produced unrooted dendrograms that included protists, yeasts, and higher eukaryotes. Bootstrap confidence estimates supported CDK-based phylogenetic groupings among the protists, fungi, and vertebrates although resolution within these groups was often insignificant. However, Trichomonas vaginalis and Giardia lamblia exhibited two of the most divergent CDK-like sequences consistent with rRNA-phylogenetic inference of early divergence of these eukaryotic lineages. In the evolution from unicellular to multicellular organisms, a constellation of amino acid residues aligning with the human, CDK N-terminal beta sheet may have undergone abrupt replacement.

show abstract

Nucleic Acid Metabolism in Trichomonas vaginalis

Cited by 8 publications

References 27 publications

Trichomonas vaginalis: Dominant G2 Period and G2 Phase Arrest in a Representative of an Early Branching Eukaryotic Lineage

Trichomonas vaginalis: Dominant G2 Period and G2 Phase Arrest in a Representative of an Early Branching Eukaryotic Lineage

Steroid hormones alter AMP hydrolysis in intact trophozoites of Trichomonas vaginalis

Molecular and phylogenetic analysis of PCR-amplified cyclin-dependent kinase (CDK) family sequences from representatives of the earliest available lineages of eukaryotes

Contact Info

Product

Resources

About