Endosymbiosis in protozoa of the Trypanosomatidae family

Souza, Wanderley de

doi:10.1016/s0378-1097(99)00005-1

Cited by 30 publications

(36 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Whilst demonstrating that the extra-axonemal PFR is not absent in endosymbiont-bearing kinetoplastids (as previously reported [12,17]) and that this organelle is therefore most probably universal in the kinetoplastids and euglenoids, we have been able to provide further insights into the relationship of molecular diversity and PFR morphotypes in these fascinating protists.…”

Section: Evolutionary Distribution Of the Pfrsupporting

confidence: 71%

See 1 more Smart Citation

Cryptic Paraflagellar Rod in Endosymbiont-Containing Kinetoplastid Protozoa

et al. 2005

View full text Add to dashboard Cite

Cilia and flagella are central to many biological processes in a diverse range of organisms. The kinetoplastid protozoa are very appealing models for the study of flagellar function, particularly in the light of the availability of extensive trypanosomatid genome information. In addition to the highly conserved 9 ؉ 2 axoneme, the kinetoplastid flagellum contains a characteristic paraflagellar rod structure (PFR). The PFR is necessary for full motility and provides support for metabolic regulators that may influence flagellar beating. However, there is an intriguing puzzle: one clade of endosymbiont-containing kinetoplastids apparently lack a PFR yet are as motile as species that possess a PFR and are able to attach to the invertebrate host epithelia. We investigated how these organisms are able to locomote despite the apparent lack of PFR. Here we have identified a PFR1 gene in the endosymbiont-bearing trypanosome Crithidia deanei. This gene is expressed in C. deanei and is able to partially complement a pfr1 null mutation in Leishmania mexicana cells, demonstrating that the encoded protein is functional. Careful reexamination of C. deanei flagellar ultrastructure revealed a greatly reduced PFR missed by many previous analyses. This affirms the PFR as a canonical organelle of kinetoplastids. Moreover, although PFR proteins have been conserved in evolution, primary sequence differences contribute to particular PFR morphotypes characteristic of different kinetoplastid species.Cilia and flagella are central to many biological processes in a diverse range of organisms. In the order Kinetoplastida-the group of flagellates that include trypanosomatid parasites and bodonids-the flagellum is the classical organelle of motility (42). In parasitic species, the kinetoplastid flagellum has also evolved to be an organelle of attachment to the invertebrate vector, playing a critical role in parasite transmission to the vertebrate host (42). Moreover, recent work shows that the kinetoplastid flagellum is also involved in cell division; positioning of the new flagellum, one of the earliest event in cell duplication, defines the axis of polarity in the dividing cell and the position of the internal organelles (31). Finally, flagellar wave reversal in a Ca 2ϩ -dependent manner as an avoidance response has been studied in trypanosomatids (39), suggesting that the flagellum in these species may also be a specialized sensory organelle.The main component of both cilia and flagella is the axoneme. This microtubule-based organelle was most probably present in the ancestor of all modern eukaryotes and is highly conserved in several deeply diverged lines. In many organisms, the axoneme is augmented by extra-axonemal structures-for example, the fibrous sheath in mammalian spermatozoa and the R-fiber of dinoflagellates. In the Kinetoplastida, a characteristic structure known as the paraflagellar rod (PFR) runs alongside the axoneme to form the flagellum. This PFR is an elegant and stable lattice-like arrangement of protein filaments which ...

show abstract

Section: Evolutionary Distribution Of the Pfrsupporting

confidence: 71%

“…Previous structural studies have reported a lack of PFR in kinetoplastids possessing an endosymbiotic bacterium (12,17). During the early phases of the identification of PFR1 and PFR2 in T. brucei, one antibody used gave a weak Western blot signal to proteins of C. deanei but not C. oncopelti (38).…”

Section: Evolutionary Distribution Of the Pfrmentioning

confidence: 97%

Cryptic Paraflagellar Rod in Endosymbiont-Containing Kinetoplastid Protozoa

et al. 2005

View full text Add to dashboard Cite

show abstract

“…7) might sequentially dephosphorylate ATP to adenosine: ATP fi ADP fi AMP fi adenosine, thus making adenosine from nucleotides -which, because of their charge, are not permeable to the plasma membrane -available to the parasites. The endosymbiont bacterium present in the cytoplasm of C. deanei supplies this host trypanosomatid with essential growth factors, such as purine bases (De Souza and Motta 1999). The ability of this cell to hydrolyze ATP, ADP and AMP (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Parasites of the genus Crithidia have been widely used as a model for biochemical studies on eukaryotic cells, as they are non-pathogenic, can be easily grown axenically in chemically defined media, and share several metabolic pathways with higher eukaryotes (Motta et al 1997;Gero 1998;De Souza and Motta 1999). A few members of this genus, such as C. deanei, harbor an endosymbiotic bacterium in the cytoplasm.…”

Section: Introductionmentioning

confidence: 99%

“…A few members of this genus, such as C. deanei, harbor an endosymbiotic bacterium in the cytoplasm. The endosymbiont supplies the host trypanosomatid with essential growth factors, such as purine bases, hemin and amino acids (Motta et al 1997;De Souza and Motta 1999). The close metabolic relationship of endosymbiont-bearing trypanosomatids accounts for the less stringent growth requirements in axenic medium, while naturally occurring symbiontfree species, such as pathogenic parasites, scavenge many of the essential nutrients they require from their hosts.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Ectonucleotide diphosphohydrolase activity in Crithidia deanei

Lemos

Pinheiro

Berrêdo-Pinho

et al. 2002

Parasitology Research

View full text Add to dashboard Cite

In this work we describe the ability of living Crithidia deanei to hydrolyze extracellular ATP. In intact cells at pH 7.2, a low level of ATP hydrolysis was observed in the absence of any divalent metal (0.41+/-0.13 nmol P(i) h(-1) 10(7) cells(-1)). The ATP hydrolysis was stimulated by MgCl(2) and the Mg(2+)-dependent ecto-ATPase activity was 4.05+/-0.17 nmol P(i) h(-1) 10(7) cells(-1). Mg(2+)-dependent ecto-ATPase activity increased linearly with cell density and with time for at least 60 min. The addition of MgCl(2) to extracellular medium increased the ecto-ATPase activity in a dose-dependent manner. At 5 mM ATP, half-maximal stimulation of ATP hydrolysis was obtained with 0.93+/-0.26 mM MgCl(2). This stimulatory activity was also observed when MgCl(2) was replaced by MnCl(2), but not CaCl(2) or SrCl(2). The apparent K(m) for Mg-ATP(2-) was 0.26+/-0.03 mM. ATP was the best substrate for this enzyme; other nucleotides, such as ITP, GTP, UTP and CTP, produced lower reaction rates. In the pH range from 6.6 to 8.4, in which the cells were viable, the acid phosphatase activity also present in this cell decreased, while the Mg(2+)-dependent ATPase activity did not change. This ecto-ATPase activity was insensitive to inhibitors of other ATPase and phosphatase activities, such as oligomycin, sodium azide, bafilomycin A(1), ouabain, vanadate, molybdate, sodium fluoride and tartrate. To confirm that this Mg(2+)-dependent ATPase was an ecto-ATPase, we used the impermeant inhibitor 4, 4'-diisothiocyanostylbene 2'-2'-disulfonic acid as well as suramin, an antagonist of P(2) purinoreceptors and inhibitor of some ecto-ATPases. These two reagents inhibited the Mg(2+)-dependent ATPase activity in a dose-dependent manner. The cell surface location of the ATP-hydrolyzing site was also confirmed by cytochemical analysis.

show abstract

Kinetoplastea

Gibson

2017

Handbook of the Protists

View full text Add to dashboard Cite

Endosymbiosis in protozoa of the Trypanosomatidae family

Cited by 30 publications

References 17 publications

Cryptic Paraflagellar Rod in Endosymbiont-Containing Kinetoplastid Protozoa

Cryptic Paraflagellar Rod in Endosymbiont-Containing Kinetoplastid Protozoa

Ectonucleotide diphosphohydrolase activity in Crithidia deanei

Kinetoplastea

Contact Info

Product

Resources

About