Journal articles on the topic 'Kinetoplasts'
To see the other types of publications on this topic, follow the link: Kinetoplasts.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Kinetoplasts.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Sinha, Krishna Murari, Jane C. Hines, and Dan S. Ray. "Cell Cycle-Dependent Localization and Properties of a Second Mitochondrial DNA Ligase in Crithidia fasciculata." Eukaryotic Cell 5, no. 1 (January 2006): 54–61. http://dx.doi.org/10.1128/ec.5.1.54-61.2006.
Full textAbstract:
ABSTRACT The mitochondrial DNA in kinetoplastid protozoa is contained in a single highly condensed structure consisting of thousands of minicircles and approximately 25 maxicircles. The disk-shaped structure is termed kinetoplast DNA (kDNA) and is located in the mitochondrial matrix near the basal body. We have previously identified a mitochondrial DNA ligase (LIG kβ) in the trypanosomatid Crithidia fasciculata that localizes to antipodal sites flanking the kDNA disk where several other replication proteins are localized. We describe here a second mitochondrial DNA ligase (LIG kα). LIG kα localizes to the kinetoplast primarily in cells that have completed mitosis and contain either a dividing kinetoplast or two newly divided kinetoplasts. Essentially all dividing or newly divided kinetoplasts show localization of LIG kα. The ligase is present on both faces of the kDNA disk and at a high level in the kinetoflagellar zone of the mitochondrial matrix. Cells containing a single nucleus show localization of the LIG kα to the kDNA but at a much lower frequency. The mRNA level of LIG kα varies during the cell cycle out of phase with that of LIG kβ. LIG kα transcript levels are maximal during the phase when cells contain two nuclei, whereas LIG kβ transcript levels are maximal during S phase. The LIG kα protein decays with a half-life of 100 min in the absence of protein synthesis. The periodic expression of the LIG kα transcript and the instability of the LIG kα protein suggest a possible role of the ligase in regulating minicircle replication.
2
Klotz, Alexander R., Beatrice W. Soh, and Patrick S. Doyle. "Equilibrium structure and deformation response of 2D kinetoplast sheets." Proceedings of the National Academy of Sciences 117, no. 1 (December 6, 2019): 121–27. http://dx.doi.org/10.1073/pnas.1911088116.
Full textAbstract:
The considerable interest in two-dimensional (2D) materials and complex molecular topologies calls for a robust experimental system for single-molecule studies. In this work, we study the equilibrium properties and deformation response of a complex DNA structure called a kinetoplast, a 2D network of thousands of linked rings akin to molecular chainmail. Examined in good solvent conditions, kinetoplasts appear as a wrinkled hemispherical sheet. The conformation of each kinetoplast is dictated by its network topology, giving it a unique shape, which undergoes small-amplitude thermal fluctuations at subsecond timescales, with a wide separation between fluctuation and diffusion timescales. They deform elastically when weakly confined and swell to their equilibrium dimensions when the confinement is released. We hope that, in the same way that linear DNA became a canonical model system on the first investigations of its polymer-like behavior, kinetoplasts can serve that role for 2D and catenated polymer systems.
3
Simpson, Alastair G. B., Julius Lukeš, and Andrew J. Roger. "The Evolutionary History of Kinetoplastids and Their Kinetoplasts." Molecular Biology and Evolution 19, no. 12 (December 1, 2002): 2071–83. http://dx.doi.org/10.1093/oxfordjournals.molbev.a004032.
Full text
4
Marande, William, Julius Lukeš, and Gertraud Burger. "Unique Mitochondrial Genome Structure in Diplonemids, the Sister Group of Kinetoplastids." Eukaryotic Cell 4, no. 6 (June 2005): 1137–46. http://dx.doi.org/10.1128/ec.4.6.1137-1146.2005.
Full textAbstract:
ABSTRACT Kinetoplastid flagellates are characterized by uniquely massed mitochondrial DNAs (mtDNAs), the kinetoplasts. Kinetoplastids of the trypanosomatid group possess two types of mtDNA molecules: maxicircles bearing protein and mitoribosomal genes and minicircles specifying guide RNAs, which mediate uridine insertion/deletion RNA editing. These circles are interlocked with one another to form dense networks. Whether these peculiar mtDNA features are restricted to kinetoplastids or prevail throughout Euglenozoa (euglenids, diplonemids, and kinetoplastids) is unknown. Here, we describe the mitochondrial genome and the mitochondrial ultrastructure of Diplonema papillatum, a member of the diplonemid flagellates, the sister group of kinetoplastids. Fluorescence and electron microscopy show a single mitochondrion per cell with an ultrastructure atypical for Euglenozoa. In addition, DNA is evenly distributed throughout the organelle rather than compacted. Molecular and electron microscopy studies distinguish numerous 6- and 7-kbp-sized mitochondrial chromosomes of monomeric circular topology and relaxed conformation in vivo. Remarkably, the cox1 gene (and probably other mitochondrial genes) is fragmented, with separate gene pieces encoded on different chromosomes. Generation of the contiguous cox1 mRNA requires trans-splicing, the precise mechanism of which remains to be determined. Taken together, the mitochondrial gene/genome structure of Diplonema is not only different from that of kinetoplastids but unique among eukaryotes as a whole.
5
Beck, Kirsten, Nathalie Acestor, Anjelique Schulfer, Atashi Anupama, Jason Carnes, Aswini K. Panigrahi, and Ken Stuart. "Trypanosoma brucei Tb927.2.6100 Is an Essential Protein Associated with Kinetoplast DNA." Eukaryotic Cell 12, no. 7 (May 6, 2013): 970–78. http://dx.doi.org/10.1128/ec.00352-12.
Full textAbstract:
ABSTRACT The mitochondrial DNA of trypanosomatid protozoa consists of a complex, intercatenated network of tens of maxicircles and thousands of minicircles. This structure, called kinetoplast DNA (kDNA), requires numerous proteins and multiprotein complexes for replication, segregation, and transcription. In this study, we used a proteomic approach to identify proteins that are associated with the kDNA network. We identified a novel protein encoded by Tb927.2.6100 that was present in a fraction enriched for kDNA and colocalized the protein with kDNA by fluorescence microscopy. RNA interference (RNAi) knockdown of its expression resulted in a growth defect and changes in the proportion of kinetoplasts and nuclei in the cell population. RNAi also resulted in shrinkage and loss of the kinetoplasts, loss of maxicircle and minicircle components of kDNA at similar rates, and (perhaps secondarily) loss of edited and pre-edited mRNA. These results indicate that the Tb927.2.6100 protein is essential for the maintenance of kDNA.
6
Tu, Xiaoming, and Ching C. Wang. "The Involvement of Two cdc2-related Kinases (CRKs) inTrypanosoma bruceiCell Cycle Regulation and the Distinctive Stage-specific Phenotypes Caused by CRK3 Depletion." Journal of Biological Chemistry 279, no. 19 (March 8, 2004): 20519–28. http://dx.doi.org/10.1074/jbc.m312862200.
Full textAbstract:
Cyclin-dependent protein kinases are among the key regulators of eukaryotic cell cycle progression. Potential functions of the five cdc2-related kinases (CRK) inTrypanosoma bruceiwere analyzed using the RNA interference (RNAi) technique. In both the procyclic and bloodstream forms ofT. brucei, CRK1 is apparently involved in controlling the G1/S transition, whereas CRK3 plays an important role in catalyzing cells across the G2/M junction. A knockdown of CRK1 caused accumulation of cells in the G1phase without apparent phenotypic change, whereas depletion of CRK3 enriched cells of both forms in the G2/M phase. However, two distinctive phenotypes were observed between the CRK3-deficient procyclic and bloodstream forms. The procyclic form has a majority of the cells containing a single enlarged nucleus plus one kinetoplast. There is also an enhanced population of anucleated cells, each containing a single kinetoplast known as the zoids (0N1K). The CRK3-depleted bloodstream form has an increased number of one nucleus-two kinetoplast cells (1N2K) and a small population containing aggregated multiple nuclei and multiple kinetoplasts. Apparently, these two forms have different mechanisms in cell cycle regulation. Although the procyclic form can be driven into cytokinesis and cell division by kinetoplast segregation without a completed mitosis, the bloodstream form cannot enter cytokinesis under the same condition. Instead, it keeps going through another G1phase and enters a new S phase resulting in an aggregate of multiple nuclei and multiple kinetoplasts in an undivided cell. The different leakiness in cell cycle regulation between two stage-specific forms of an organism provides an interesting and useful model for further understanding the evolution of cell cycle control among the eukaryotes.
7
Robinson, D. R., T. Sherwin, A. Ploubidou, E. H. Byard, and K. Gull. "Microtubule polarity and dynamics in the control of organelle positioning, segregation, and cytokinesis in the trypanosome cell cycle." Journal of Cell Biology 128, no. 6 (March 15, 1995): 1163–72. http://dx.doi.org/10.1083/jcb.128.6.1163.
Full textAbstract:
Trypanosoma brucei has a precisely ordered microtubule cytoskeleton whose morphogenesis is central to cell cycle events such as organelle positioning, segregation, mitosis, and cytokinesis. We have defined microtubule polarity and show the + ends of the cortical microtubules to be at the posterior end of the cell. Measurements of organelle positions through the cell cycle reveal a high degree of coordinate movement and a relationship with overall cell extension. Quantitative analysis of the segregation of the replicated mitochondrial genome (the kinetoplast) by the flagellar basal bodies identifies a new G2 cell cycle event marker. The subsequent mitosis then positions one "daughter" nucleus into the gap between the segregated basal bodies/kinetoplasts. The anterior daughter nucleus maintains its position relative to the anterior of the cell, suggesting an effective yet cryptic nuclear positioning mechanism. Inhibition of microtubule dynamics by rhizoxin results in a phenomenon whereby cells, which have segregated their kinetoplasts yet are compromised in mitosis, cleave into a nucleated portion and a flagellated, anucleate, cytoplast. We term these cytoplasts "zoids" and show that they contain the posterior (new) flagellum and associated basal-body/kinetoplast complex. Examination of zoids suggests a role for the flagellum attachment zone (FAZ) in defining the position for the axis of cleavage in trypanosomes. Progression through cytokinesis, (zoid formation) while mitosis is compromised, suggests that the dependency relationships leading to the classical cell cycle check points may be altered in trypanosomes, to take account of the need to segregate two unit genomes (nuclear and mitochondrial) in this cell.
8
Ebiloma, Godwin U., Nahandoo Ichoron, Weam Siheri, David G. Watson, John O. Igoli, and Harry P. De Koning. "The Strong Anti-Kinetoplastid Properties of Bee Propolis: Composition and Identification of the Active Agents and Their Biochemical Targets." Molecules 25, no. 21 (November 5, 2020): 5155. http://dx.doi.org/10.3390/molecules25215155.
Full textAbstract:
The kinetoplastids are protozoa characterized by the presence of a distinctive organelle, called the kinetoplast, which contains a large amount of DNA (kinetoplast DNA (kDNA)) inside their single mitochondrion. Kinetoplastids of medical and veterinary importance include Trypanosoma spp. (the causative agents of human and animal African Trypanosomiasis and of Chagas disease) and Leishmania spp. (the causative agents of the various forms of leishmaniasis). These neglected diseases affect millions of people across the globe, but drug treatment is hampered by the challenges of toxicity and drug resistance, among others. Propolis (a natural product made by bees) and compounds isolated from it are now being investigated as novel treatments of kinetoplastid infections. The anti-kinetoplastid efficacy of propolis is probably a consequence of its reported activity against kinetoplastid parasites of bees. This article presents a review of the reported anti-kinetoplastid potential of propolis, highlighting its anti-kinetoplastid activity in vitro and in vivo regardless of geographical origin. The mode of action of propolis depends on the organism it is acting on and includes growth inhibition, immunomodulation, macrophage activation, perturbation of the cell membrane architecture, phospholipid disturbances, and mitochondrial targets. This gives ample scope for further investigations toward the rational development of sustainable anti-kinetoplastid drugs.
9
Sullenberger, Catherine, Benjamin Hoffman, Justin Wiedeman, Gaurav Kumar, and Kojo Mensa-Wilmot. "Casein kinase TbCK1.2 regulates division of kinetoplast DNA, and movement of basal bodies in the African trypanosome." PLOS ONE 16, no. 4 (April 16, 2021): e0249908. http://dx.doi.org/10.1371/journal.pone.0249908.
Full textAbstract:
The single mitochondrial nucleoid (kinetoplast) ofTrypanosoma bruceiis found proximal to a basal body (mature (mBB)/probasal body (pBB) pair). Kinetoplast inheritance requires synthesis of, and scission of kinetoplast DNA (kDNA) generating two kinetoplasts that segregate with basal bodies into daughter cells. Molecular details of kinetoplast scission and the extent to which basal body separation influences the process are unavailable. To address this topic, we followed basal body movements in bloodstream trypanosomes following depletion of protein kinase TbCK1.2 which promotes kinetoplast division. In control cells we found that pBBs are positioned 0.4 um from mBBs in G1, and they mature after separating from mBBs by at least 0.8 um: mBB separation reaches ~2.2 um. These data indicate that current models of basal body biogenesis in which pBBs mature in close proximity to mBBs may need to be revisited. Knockdown of TbCK1.2 produced trypanosomes containing one kinetoplast and two nuclei (1K2N), increased the percentage of cells with uncleaved kDNA 400%, decreased mBB spacing by 15%, and inhibited cytokinesis 300%. We conclude that (a) separation of mBBs beyond a threshold of 1.8 um correlates with division of kDNA, and (b) TbCK1.2 regulates kDNA scission. We propose a Kinetoplast Division Factor hypothesis that integrates these data into a pathway for biogenesis of two daughter mitochondrial nucleoids.
10
Ferguson, M. L., A. F. Torri, D. Pérez-Morga, D. C. Ward, and P. T. Englund. "Kinetoplast DNA replication: mechanistic differences between Trypanosoma brucei and Crithidia fasciculata." Journal of Cell Biology 126, no. 3 (August 1, 1994): 631–39. http://dx.doi.org/10.1083/jcb.126.3.631.
Full textAbstract:
Kinetoplast DNA, the mitochondrial DNA of trypanosomatid parasites, is a network containing several thousand minicircles and a few dozen maxicircles. We compared kinetoplast DNA replication in Trypanosoma brucei and Crithidia fasciculata using fluorescence in situ hybridization and electron microscopy of isolated networks. One difference is in the location of maxicircles in situ. In C. fasciculata, maxicircles are concentrated in discrete foci embedded in the kinetoplast disk; during replication the foci increase in number but remain scattered throughout the disk. In contrast, T. brucei maxicircles generally fill the entire disk. Unlike those in C. fasciculata, T. brucei maxicircles become highly concentrated in the central region of the kinetoplast after replication; then during segregation they redistribute throughout the daughter kinetoplasts. T. brucei and C. fasciculata also differ in the pattern of attachment of newly synthesized minicircles to the network. In C. fasciculata it was known that minicircles are attached at two antipodal sites but subsequently are found uniformly distributed around the network periphery, possibly due to a relative movement of the kinetoplast disk and two protein complexes responsible for minicircle synthesis and attachment. In T. brucei, minicircles appear to be attached at two antipodal sites but then remain concentrated in these two regions. Therefore, the relative movement of the kinetoplast and the two protein complexes may not occur in T. brucei.
11
Moreira, David, Purificación López-García, and Keith Vickerman. "An updated view of kinetoplastid phylogeny using environmental sequences and a closer outgroup: proposal for a new classification of the class Kinetoplastea." International Journal of Systematic and Evolutionary Microbiology 54, no. 5 (September 1, 2004): 1861–75. http://dx.doi.org/10.1099/ijs.0.63081-0.
Full textAbstract:
Given their ecological and medical importance, the classification of the kinetoplastid protists (class Kinetoplastea) has attracted much scientific attention for a long time. Morphology-based taxonomic schemes distinguished two major kinetoplastid groups: the strictly parasitic, uniflagellate trypanosomatids and the biflagellate bodonids. Molecular phylogenetic analyses based on 18S rRNA sequence comparison suggested that the trypanosomatids emerged from within the bodonids. However, these analyses revealed a huge evolutionary distance between the kinetoplastids and their closest relatives (euglenids and diplonemids) that makes very difficult the correct inference of the phylogenetic relationships between the different kinetoplastid groups. Using direct PCR amplification of 18S rRNA genes from hydrothermal vent samples, several new kinetoplastid-like sequences have been reported recently. Three of them emerge robustly at the base of the kinetoplastids, breaking the long branch leading to the euglenids and diplonemids. One of these sequences belongs to a close relative of Ichthyobodo necator (a fish parasite) and of the ‘Perkinsiella amoebae’-like endosymbiont of Neoparamoeba spp. amoebae. The authors have studied the reliability of their basal position and used all these slow-evolving basal-emerging sequences as a close outgroup to analyse the phylogeny of the apical kinetoplastids. They thus find a much more stable and resolved kinetoplastid phylogeny, which supports the monophyly of groups that very often emerged as polyphyletic in the trees rooted using the traditional, distant outgroup sequences. A new classification of the class Kinetoplastea is proposed based on the results of the phylogenetic analysis presented. This class is now subdivided into two new subclasses, Prokinetoplastina (accommodating the basal species I. necator and ‘Perkinsiella amoebae’) and Metakinetoplastina (containing the Trypanosomatida together with three additional new orders: Eubodonida, Parabodonida and Neobodonida). The classification of the species formerly included in the genus Bodo is also revised, with the amendment of this genus and the genus Parabodo and the creation of a new genus, Neobodo.
12
Colasante, Claudia, Vincent P. Alibu, Simon Kirchberger, Joachim Tjaden, Christine Clayton, and Frank Voncken. "Characterization and Developmentally Regulated Localization of the Mitochondrial Carrier Protein Homologue MCP6 from Trypanosoma brucei." Eukaryotic Cell 5, no. 8 (August 2006): 1194–205. http://dx.doi.org/10.1128/ec.00096-06.
Full textAbstract:
ABSTRACT Proteins of the mitochondrial carrier family (MCF) are located mainly in the inner mitochondrial membrane and mediate the transport of a large range of metabolic intermediates. The genome of Trypanosoma brucei harbors 29 genes encoding different MCF proteins. We describe here the characterization of MCP6, a novel T. brucei MCF protein. Sequence comparison and phylogenetic reconstruction revealed that MCP6 is closely related to different mitochondrial ADP/ATP and calcium-dependent solute carriers, including the ATP-Mg/Pi carrier of Homo sapiens. However, MCP6 lacks essential amino acids and sequence motifs conserved in these metabolite transporters, and functional reconstitution and transport assays with E. coli suggested that this protein indeed does not function as an ADP/ATP or ATP-Mg/Pi carrier. The subcellular localization of MCP6 is developmentally regulated: in bloodstream-form trypanosomes, the protein is predominantly glycosomal, whereas in the procyclic form, it is found mainly in the mitochondria. Depletion of MCP6 in procyclic trypanosomes resulted in growth inhibition, an increased cell size, aberrant numbers of nuclei and kinetoplasts, and abnormal kinetoplast morphology, suggesting that depletion of MCP6 inhibits division of the kinetoplast.
13
Birkenmeyer, L., and D. S. Ray. "Replication of kinetoplast DNA in isolated kinetoplasts from Crithidia fasciculata. Identification of minicircle DNA replication intermediates." Journal of Biological Chemistry 261, no. 5 (February 1986): 2362–68. http://dx.doi.org/10.1016/s0021-9258(17)35945-8.
Full text
14
Yang, Gyongseon, Gahee Choi, and Joo Hwan No. "Antileishmanial Mechanism of Diamidines Involves Targeting Kinetoplasts." Antimicrobial Agents and Chemotherapy 60, no. 11 (September 6, 2016): 6828–36. http://dx.doi.org/10.1128/aac.01129-16.
Full textAbstract:
ABSTRACTLeishmaniasis is a disease caused by pathogenicLeishmaniaparasites; current treatments are toxic and expensive, and drug resistance has emerged. While pentamidine, a diamidine-type compound, is one of the treatments, its antileishmanial mechanism of action has not been investigated in depth. Here we tested several diamidines, including pentamidine and its analog DB75, againstLeishmania donovaniand elucidated their antileishmanial mechanisms. We identified three promising new antileishmanial diamidine compounds with 50% effective concentrations (EC50s) of 3.2, 3.4, and 4.5 μM, while pentamidine and DB75 exhibited EC50s of 1.46 and 20 μM, respectively. The most potent antileishmanial inhibitor, compound 1, showed strong DNA binding properties, with a shift in the melting temperature (ΔTm) of 24.2°C, whereas pentamidine had a ΔTmvalue of 2.1°C, and DB75 had a ΔTmvalue of 7.7°C. Additionally, DB75 localized inL. donovanikinetoplast DNA (kDNA) and mitochondria but not in nuclear DNA (nDNA). For 2 new diamidines, strong localization signals were observed in kDNA at 1 μM, and at higher concentrations, the signals also appeared in nuclei. All tested diamidines showed selective and dose-dependent inhibition of kDNA, but not nDNA, replication, likely by inhibitingL. donovanitopoisomerase IB. Overall, these results suggest that diamidine antileishmanial compounds exert activity by accumulating toward and blocking replication of parasite kDNA.
15
Sykes, Steven E., and Stephen L. Hajduk. "Dual Functions of α-Ketoglutarate Dehydrogenase E2 in the Krebs Cycle and Mitochondrial DNA Inheritance in Trypanosoma brucei." Eukaryotic Cell 12, no. 1 (November 2, 2012): 78–90. http://dx.doi.org/10.1128/ec.00269-12.
Full textAbstract:
ABSTRACT The dihydrolipoyl succinyltransferase (E2) of the multisubunit α-ketoglutarate dehydrogenase complex (α-KD) is an essential Krebs cycle enzyme commonly found in the matrices of mitochondria. African trypanosomes developmentally regulate mitochondrial carbohydrate metabolism and lack a functional Krebs cycle in the bloodstream of mammals. We found that despite the absence of a functional α-KD, bloodstream form (BF) trypanosomes express α-KDE2, which localized to the mitochondrial matrix and inner membrane. Furthermore, α-KDE2 fractionated with the mitochondrial genome, the kinetoplast DNA (kDNA), in a complex with the flagellum. A role for α-KDE2 in kDNA maintenance was revealed in α-KDE2 RNA interference (RNAi) knockdowns. Following RNAi induction, bloodstream trypanosomes showed pronounced growth reduction and often failed to equally distribute kDNA to daughter cells, resulting in accumulation of cells devoid of kDNA (dyskinetoplastic) or containing two kinetoplasts. Dyskinetoplastic trypanosomes lacked mitochondrial membrane potential and contained mitochondria of substantially reduced volume. These results indicate that α-KDE2 is bifunctional, both as a metabolic enzyme and as a mitochondrial inheritance factor necessary for the distribution of kDNA networks to daughter cells at cytokinesis.
16
Selvapandiyan, Angamuthu, Praveen Kumar, James C. Morris, Jeffrey L. Salisbury, Ching C. Wang, and Hira L. Nakhasi. "Centrin1 Is Required for Organelle Segregation and Cytokinesis in Trypanosoma brucei." Molecular Biology of the Cell 18, no. 9 (September 2007): 3290–301. http://dx.doi.org/10.1091/mbc.e07-01-0022.
Full textAbstract:
Centrin is a calcium-binding centrosome/basal body–associated protein involved in duplication and segregation of these organelles in eukaryotes. We had shown that disruption of one of the centrin genes (centrin1) in Leishmania amastigotes resulted in failure of both basal body duplication and cytokinesis. Here, we undertook to define the role of centrin1 (TbCen1) in the duplication and segregation of basal body and its associated organelles kinetoplast and Golgi, as well as its role in cytokinesis of the procyclic form of Trypanosoma brucei by depleting its protein using RNA inhibition methodology. TbCen1-depleted cells showed significant reduction in growth compared with control cells. Morphological analysis of these cells showed they were large and pleomorphic with multiple detached flagella. Both immunofluorescence assays using organelle-specific antibodies and electron microscopic analysis showed that TbCen1-deficient cells contained multiple basal bodies, kinetoplasts, Golgi, and nuclei. These multiple organelles were, however, closely clustered together, indicating duplication without segregation in the absence of centrin. This failure in organelle segregation may be the likely cause of inhibition of cytokinesis, suggesting for the first time a new and unique role for centrin in the segregation of organelles without affecting their multiplication in the procyclic form of T. brucei.
17
Sheline, C., T. Melendy, and D. S. Ray. "Replication of DNA minicircles in kinetoplasts isolated from Crithidia fasciculata: structure of nascent minicircles." Molecular and Cellular Biology 9, no. 1 (January 1989): 169–76. http://dx.doi.org/10.1128/mcb.9.1.169-176.1989.
Full textAbstract:
We have previously described an isolated kinetoplast system from Crithidia fasciculata capable of ATP-dependent replication of kinetoplast DNA minicircles (L. Birkenmeyer and D.S. Ray, J. Biol. Chem. 261: 2362-2368, 1986). We present here the identification of two new minicircle species observed in short pulse-labeling experiments in this system. The earliest labeled minicircle species (component A) contains both nascent H and L strands and is heterogeneous in sedimentation and electrophoretic migration. Component A has characteristics consistent with a Cairns-type structure in which the L strand is the leading strand and the H strand is the lagging strand. The other new species (component B) has a nascent 2.5-kilobase linear L strand with a single discontinuity that mapped to either of two alternative origins located 180 degrees apart on the minicircle map. Component B could be repaired to a covalently closed form by Escherichia coli polymerase I and T4 ligase but not by T4 polymerase and T4 ligase. Even though component B has a single gap in one strand, it had an electrophoretic mobility on an agarose gel (minus ethidium bromide) similar to that of a supercoiled circle with three supertwists. Treatment of component B with topoisomerase II converted it to a form that comigrated with a nicked open circular form (replicative form II). These results indicate that component B is a knotted topoisomer of a kinetoplast DNA minicircle with a single gap in the L strand.
18
Sheline, C., T. Melendy, and D. S. Ray. "Replication of DNA minicircles in kinetoplasts isolated from Crithidia fasciculata: structure of nascent minicircles." Molecular and Cellular Biology 9, no. 1 (January 1989): 169–76. http://dx.doi.org/10.1128/mcb.9.1.169.
Full textAbstract:
We have previously described an isolated kinetoplast system from Crithidia fasciculata capable of ATP-dependent replication of kinetoplast DNA minicircles (L. Birkenmeyer and D.S. Ray, J. Biol. Chem. 261: 2362-2368, 1986). We present here the identification of two new minicircle species observed in short pulse-labeling experiments in this system. The earliest labeled minicircle species (component A) contains both nascent H and L strands and is heterogeneous in sedimentation and electrophoretic migration. Component A has characteristics consistent with a Cairns-type structure in which the L strand is the leading strand and the H strand is the lagging strand. The other new species (component B) has a nascent 2.5-kilobase linear L strand with a single discontinuity that mapped to either of two alternative origins located 180 degrees apart on the minicircle map. Component B could be repaired to a covalently closed form by Escherichia coli polymerase I and T4 ligase but not by T4 polymerase and T4 ligase. Even though component B has a single gap in one strand, it had an electrophoretic mobility on an agarose gel (minus ethidium bromide) similar to that of a supercoiled circle with three supertwists. Treatment of component B with topoisomerase II converted it to a form that comigrated with a nicked open circular form (replicative form II). These results indicate that component B is a knotted topoisomer of a kinetoplast DNA minicircle with a single gap in the L strand.
19
Agbe, Ade, and K. Lemone Yielding. "Kinetoplasts Play an Important Role in the Drug Responses of Trypanosoma brucei." Journal of Parasitology 81, no. 6 (December 1995): 968. http://dx.doi.org/10.2307/3284050.
Full text
20
Deng, Jau-Shyong, Richard D. Sontheimer, Mary F. Lipscomb, and James N. Gilliam. "The binding of antihistone antibodies tocrithidia luciliae kinetoplasts is growth cycle-dependent." Arthritis & Rheumatism 28, no. 2 (February 1985): 163–68. http://dx.doi.org/10.1002/art.1780280210.
Full text
21
Engel, M. L., and D. S. Ray. "A structure-specific DNA endonuclease is enriched in kinetoplasts purified from Crithidia fasciculata." Nucleic Acids Research 26, no. 20 (October 1, 1998): 4733–38. http://dx.doi.org/10.1093/nar/26.20.4733.
Full text
22
Gonz�lez-Halphen, Diego, and Dmitri A. Maslov. "NADH-ubiquinone oxidoreductase activity in the kinetoplasts of the plant trypanosomatid Phytomonas serpens." Parasitology Research 92, no. 4 (March 1, 2004): 341–46. http://dx.doi.org/10.1007/s00436-003-1058-4.
Full text
23
Kumar, Praveen, and C. C. Wang. "Dissociation of Cytokinesis Initiation from Mitotic Control in a Eukaryote." Eukaryotic Cell 5, no. 1 (January 2006): 92–102. http://dx.doi.org/10.1128/ec.5.1.92-102.2006.
Full textAbstract:
ABSTRACTCytokinesis is initiated only after mitotic exit in eukaryotes. However, in the insect (procyclic) form of an ancient protist,Trypanosoma brucei, a blockade at the G2/M checkpoint results in an enrichment of anucleate cells (zoids), suggesting separated regulations between mitosis and cytokinesis (X. Tu and C. C. Wang, J. Biol. Chem.279:20519-20528, 2004). Polo-like kinases (Plks) are known to play critical roles in controlling both mitosis and cytokinesis. A singlePlkhomologue inT. brucei, TbPLK, was found to be capable of complementing the Plk (Cdc5) functions inSaccharomyces cerevisiae, thus raising the question of how it may function in the trypanosome with cytokinesis dissociated from mitosis. Depletion of TbPLK in the procyclic form ofT. bruceiby RNA interference resulted in growth arrest with accumulation of multiple nuclei, kinetoplasts, basal bodies, and flagella in approximately equal numbers among individual cells. There were, however, few zoids detectable, indicating inhibited cytokinesis with unblocked mitosis and kinetoplast segregation. TbPLK is thus apparently involved only in initiating cytokinesis inT. brucei. Overexpression of TbPLK in the trypanosome did not affect cell growth, but 13% of the resulting population was in the zoid form, suggesting runaway cytokinesis. An immunofluorescence assay indicated that TbPLK was localized in a chain of likely flagellum attachment zones in the cytoskeleton. In a dividing cell, a new line of such zones appeared closely paralleling the existing one, which could constitute the cleavage furrow. An exposed region of TbPLK at the anterior tip of the cell may provide the trigger of cytokinesis. Taken together, our results revealed a novel mechanism of cytokinesis initiation in the trypanosome that may serve as a useful model for further in-depth investigations.
24
Ashraf, M., R. A. Nesbitt, P. A. Humphrey, M. Siewe, and C. M. Lee. "Comparative positions of kinetoplasts in Trypanosoma musculi and Trypanosoma lewisi during development in vitro." Cell Proliferation 35, no. 5 (September 19, 2002): 269–73. http://dx.doi.org/10.1046/j.1365-2184.2002.00242.x.
Full text
25
Wideman, Jeremy G., Gordon Lax, Guy Leonard, David S. Milner, Raquel Rodríguez-Martínez, Alastair G. B. Simpson, and Thomas A. Richards. "A single-cell genome reveals diplonemid-like ancestry of kinetoplastid mitochondrial gene structure." Philosophical Transactions of the Royal Society B: Biological Sciences 374, no. 1786 (October 7, 2019): 20190100. http://dx.doi.org/10.1098/rstb.2019.0100.
Full textAbstract:
Euglenozoa comprises euglenids, kinetoplastids, and diplonemids, with each group exhibiting different and highly unusual mitochondrial genome organizations. Although they are sister groups, kinetoplastids and diplonemids have very distinct mitochondrial genome architectures, requiring widespread insertion/deletion RNA editing and extensive trans -splicing, respectively, in order to generate functional transcripts. The evolutionary history by which these differing processes arose remains unclear. Using single-cell genomics, followed by small sub unit ribosomal DNA and multigene phylogenies, we identified an isolated marine cell that branches on phylogenetic trees as a sister to known kinetoplastids. Analysis of single-cell amplified genomic material identified multiple mitochondrial genome contigs. These revealed a gene architecture resembling that of diplonemid mitochondria, with small fragments of genes encoded out of order and or on different contigs, indicating that these genes require extensive trans -splicing. Conversely, no requirement for kinetoplastid-like insertion/deletion RNA-editing was detected. Additionally, while we identified some proteins so far only found in kinetoplastids, we could not unequivocally identify mitochondrial RNA editing proteins. These data invite the hypothesis that extensive genome fragmentation and trans -splicing were the ancestral states for the kinetoplastid-diplonemid clade but were lost during the kinetoplastid radiation. This study demonstrates that single-cell approaches can successfully retrieve lineages that represent important new branches on the tree of life, and thus can illuminate major evolutionary and functional transitions in eukaryotes. This article is part of a discussion meeting issue ‘Single cell ecology’.
26
Tu, Xiaoming, and Ching C. Wang. "Pairwise Knockdowns of cdc2-Related Kinases (CRKs) in Trypanosoma brucei Identified the CRKs for G1/S and G2/M Transitions and Demonstrated Distinctive Cytokinetic Regulations between Two Developmental Stages of the Organism." Eukaryotic Cell 4, no. 4 (April 2005): 755–64. http://dx.doi.org/10.1128/ec.4.4.755-764.2005.
Full textAbstract:
ABSTRACT Expression of the cdc2-related kinase 3 (CRK3) together with expression of CRK1, -2, -4, or -6, were knocked down in pairs in the procyclic and bloodstream forms of Trypanosoma brucei, using the RNA interference technique. Double knockdowns of CRK3 and CRK2, CRK4, or CRK6 exerted significant growth inhibition and enriched the cells in G2/M phase, whereas a CRK3 plus CRK1 (CRK3 + CRK1) knockdown arrested cells in both G1/S and G2/M transitions. Thus, CRK1 and CRK3 are apparently the kinases regulating the G1/S and G2/M checkpoint passages, respectively, whereas the other CRKs are probably playing only minor roles in cell cycle regulation. A CRK1 + CRK2 knockdown in the procyclic form was found to cause aberrant posterior cytoskeletal morphogenesis (X. M. Tu and C. C. Wang, Mol. Biol. Cell 16:97-105, 2005). A CRK3 + CRK2 knockdown, however, did not lead to such a change, suggesting that CRK2 depletion can lead to the abnormal morphogenesis only when procyclic-form cells are arrested in the G1 phase. The G2/M-arrested procyclic form produces up to 20% stumpy anucleated cells (zoids) in the population, suggesting that cytokinesis and cell division are not blocked by mitotic arrest but are apparently driven to completion by the kinetoplast cycle. In the bloodstream form, however, G2/M arrest resulted in little zoid formation but, instead, enriched a population of cells each containing multiple kinetoplasts, basal bodies, and flagella and an aggregate of multiple nuclei, indicating failure in entering cytokinesis. The two different cytokinetic regulations between two distinct stage-specific forms of the same organism may provide an interesting and useful model for further understanding the evolution of cytokinetic control among eukaryotes.
27
Santos, Filipe Martins, Nayara Yoshie Sano, Sany Caroline Liberal, Maria Augusta Dario, Wesley Arruda Gimenes Nantes, Fernanda Moreira Alves, Alanderson Rodrigues da Silva, et al. "Kinetoplastid Species Maintained by a Small Mammal Community in the Pantanal Biome." Pathogens 11, no. 10 (October 19, 2022): 1205. http://dx.doi.org/10.3390/pathogens11101205.
Full textAbstract:
Kinetoplastids include species economically important in agriculture, livestock, and human health. We evaluated the richness of kinetoplastids that infect small mammals in patches of unflooded forests in the Pantanal biome, an area where we hypothesize that its diversity is higher than currently recognized. Hemocultures (HC) and Next Generation Sequencing (NGS) targeting the 18S rDNA gene were employed for the detection of kinetoplastids. We grouped the positive samples into pools for each small mammal species (Monodelphis domestica, Thylamys macrurus, Oecomys mamorae, Thrichomys fosteri, Clyomys laticeps, and Holochilus chacaris). Eight parasite species were identified: Leishmania amazonensis, L. infantum; Trypanosoma cascavelli (HC + NGS), T. cruzi, T. lainsoni, T. rangeli (HC + NGS), Trypanosoma sp. DID, and Neobodo sp. The use of a tool as sensitive as NGS has increased our awareness of the diversity of kinetoplastids, as well as their host range, with emphasis on the species O. mamorae (seven kinetoplastid species, excepting T. cascavelli in a pool of nine individuals) and T. macrurus (four kinetoplastid species in a single individual). Furthermore, L. infantum and L. amazonensis infections were described in small mammals from this region for the first time. These findings make it mandatory to revisit the kinetoplastids/host associations proposed so far.
28
Baker, Nicola, Graham Hamilton, Jonathan M. Wilkes, Sebastian Hutchinson, Michael P. Barrett, and David Horn. "Vacuolar ATPase depletion affects mitochondrial ATPase function, kinetoplast dependency, and drug sensitivity in trypanosomes." Proceedings of the National Academy of Sciences 112, no. 29 (July 6, 2015): 9112–17. http://dx.doi.org/10.1073/pnas.1505411112.
Full textAbstract:
Kinetoplastid parasites cause lethal diseases in humans and animals. The kinetoplast itself contains the mitochondrial genome, comprising a huge, complex DNA network that is also an important drug target. Isometamidium, for example, is a key veterinary drug that accumulates in the kinetoplast in African trypanosomes. Kinetoplast independence and isometamidium resistance are observed where certain mutations in the F1-γ-subunit of the two-sector F1Fo-ATP synthase allow for Fo-independent generation of a mitochondrial membrane potential. To further explore kinetoplast biology and drug resistance, we screened a genome-scale RNA interference library in African trypanosomes for isometamidium resistance mechanisms. Our screen identified 14 V-ATPase subunits and all 4 adaptin-3 subunits, implicating acidic compartment defects in resistance; V-ATPase acidifies lysosomes and related organelles, whereas adaptin-3 is responsible for trafficking among these organelles. Independent strains with depleted V-ATPase or adaptin-3 subunits were isometamidium resistant, and chemical inhibition of the V-ATPase phenocopied this effect. While drug accumulation in the kinetoplast continued after V-ATPase subunit depletion, acriflavine-induced kinetoplast loss was specifically tolerated in these cells and in cells depleted for adaptin-3 or endoplasmic reticulum membrane complex subunits, also identified in our screen. Consistent with kinetoplast dispensability, V-ATPase defective cells were oligomycin resistant, suggesting ATP synthase uncoupling and bypass of the normal Fo-A6-subunit requirement; this subunit is the only kinetoplast-encoded product ultimately required for viability in bloodstream-form trypanosomes. Thus, we describe 30 genes and 3 protein complexes associated with kinetoplast-dependent growth. Mutations affecting these genes could explain natural cases of dyskinetoplasty and multidrug resistance. Our results also reveal potentially conserved communication between the compartmentalized two-sector rotary ATPases.
29
Gadelha, Catarina, Bill Wickstead, Wanderley de Souza, Keith Gull, and Narcisa Cunha-e-Silva. "Cryptic Paraflagellar Rod in Endosymbiont-Containing Kinetoplastid Protozoa." Eukaryotic Cell 4, no. 3 (March 2005): 516–25. http://dx.doi.org/10.1128/ec.4.3.516-525.2005.
Full textAbstract:
ABSTRACT 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.
30
Robinson, D. R., and K. Gull. "The configuration of DNA replication sites within the Trypanosoma brucei kinetoplast." Journal of Cell Biology 126, no. 3 (August 1, 1994): 641–48. http://dx.doi.org/10.1083/jcb.126.3.641.
Full textAbstract:
The kinetoplast is a concatenated network of circular DNA molecules found in the mitochondrion of many trypanosomes. This mass of DNA is replicated in a discrete "S" phase in the cell cycle. We have tracked the incorporation of the thymidine analogue 5-bromodeoxyuridine into newly replicated DNA by immunofluorescence and novel immunogold labeling procedures. This has allowed the detection of particular sites of replicated DNA in the replicating and segregating kinetoplast. These studies provide a new method for observing kinetoplast DNA (kDNA) replication patterns at high resolution. The techniques reveal that initially the pattern of replicated DNA is antipodal and can be detected both on isolated complexes and in replicating kDNA in vivo. In Trypanosoma brucei the opposing edges of replicating kDNA never extend around the complete circumference of the network, as seen in other kinetoplastids. Furthermore, crescent-shaped labeling patterns are formed which give way to labeling of most of the replicating kDNA except the characteristic midzone. The configuration of these sites of replicated DNA molecules is different to previous studies on organisms such as Crithidia fasciculata, suggesting differences in the timing of replication of mini and maxicircles and/or organization of the replicative apparatus in the kinetoplast of the African trypanosome.
31
Royer, Michael, and Mark Crowe. "American Cutaneous Leishmaniasis." Archives of Pathology & Laboratory Medicine 126, no. 4 (April 1, 2002): 471–73. http://dx.doi.org/10.5858/2002-126-0471-acl.
Full textAbstract:
Abstract We present 3 cases of American cutaneous leishmaniasis occurring in soldiers of a unit of US Army Rangers who parachuted into the jungles of Panama. Shortly after returning to the United States, these 3 soldiers each developed a crusted, indurated papule, which slowly enlarged during the following 6 weeks. Routine microscopy of skin biopsies revealed a dermal granulomatous inflammation and a predominantly lymphoid infiltrate. Numerous histiocytes contained small oval organisms with bar-shaped paranuclear kinetoplasts, morphologically consistent with leishmanial parasites. Cultures grew Leishmaniasis brasiliensis, subspecies panamensis. The soldiers were treated with intravenous pentavalent antimonial therapy daily for 20 days with good clinical improvement. Epidemics of leishmaniasis occur periodically in tropical regions of the world, and leishmaniasis has emerged in new settings, for example, as an acquired immunodeficiency syndrome–associated opportunistic infection. With an increasingly mobile society, it is important to be familiar with the clinical and histopathologic appearance of conditions such as leishmaniasis, which are common in tropical and subtropical regions and are increasingly significant in other regions of the world.
32
Rojas-Pirela, Maura, Diego Andrade-Alviárez, Verónica Rojas, Ulrike Kemmerling, Ana J. Cáceres, Paul A. Michels, Juan Luis Concepción, and Wilfredo Quiñones. "Phosphoglycerate kinase: structural aspects and functions, with special emphasis on the enzyme from Kinetoplastea." Open Biology 10, no. 11 (November 2020): 200302. http://dx.doi.org/10.1098/rsob.200302.
Full textAbstract:
Phosphoglycerate kinase (PGK) is a glycolytic enzyme that is well conserved among the three domains of life. PGK is usually a monomeric enzyme of about 45 kDa that catalyses one of the two ATP-producing reactions in the glycolytic pathway, through the conversion of 1,3-bisphosphoglycerate (1,3BPGA) to 3-phosphoglycerate (3PGA). It also participates in gluconeogenesis, catalysing the opposite reaction to produce 1,3BPGA and ADP. Like most other glycolytic enzymes, PGK has also been catalogued as a moonlighting protein, due to its involvement in different functions not associated with energy metabolism, which include pathogenesis, interaction with nucleic acids, tumorigenesis progression, cell death and viral replication. In this review, we have highlighted the overall aspects of this enzyme, such as its structure, reaction kinetics, activity regulation and possible moonlighting functions in different protistan organisms, especially both free-living and parasitic Kinetoplastea. Our analysis of the genomes of different kinetoplastids revealed the presence of open-reading frames (ORFs) for multiple PGK isoforms in several species. Some of these ORFs code for unusually large PGKs. The products appear to contain additional structural domains fused to the PGK domain. A striking aspect is that some of these PGK isoforms are predicted to be catalytically inactive enzymes or ‘dead’ enzymes. The roles of PGKs in kinetoplastid parasites are analysed, and the apparent significance of the PGK gene duplication that gave rise to the different isoforms and their expression in Trypanosoma cruzi is discussed.
33
Morales, Jorge, Muneaki Hashimoto, Tom A. Williams, Hiroko Hirawake-Mogi, Takashi Makiuchi, Akiko Tsubouchi, Naoko Kaga, et al. "Differential remodelling of peroxisome function underpins the environmental and metabolic adaptability of diplonemids and kinetoplastids." Proceedings of the Royal Society B: Biological Sciences 283, no. 1830 (May 11, 2016): 20160520. http://dx.doi.org/10.1098/rspb.2016.0520.
Full textAbstract:
The remodelling of organelle function is increasingly appreciated as a central driver of eukaryotic biodiversity and evolution. Kinetoplastids including Trypanosoma and Leishmania have evolved specialized peroxisomes, called glycosomes. Glycosomes uniquely contain a glycolytic pathway as well as other enzymes, which underpin the physiological flexibility of these major human pathogens. The sister group of kinetoplastids are the diplonemids, which are among the most abundant eukaryotes in marine plankton. Here we demonstrate the compartmentalization of gluconeogenesis, or glycolysis in reverse, in the peroxisomes of the free-living marine diplonemid, Diplonema papillatum . Our results suggest that peroxisome modification was already under way in the common ancestor of kinetoplastids and diplonemids, and raise the possibility that the central importance of gluconeogenesis to carbon metabolism in the heterotrophic free-living ancestor may have been an important selective driver. Our data indicate that peroxisome modification is not confined to the kinetoplastid lineage, but has also been a factor in the success of their free-living euglenozoan relatives.
34
Banerjee, Bijoylaxmi, Nilkantha Sen, and Hemanta K. Majumder. "Identification of a Functional Type IA Topoisomerase, LdTopIIIβ, from Kinetoplastid Parasite Leishmania donovani." Enzyme Research 2011 (May 2, 2011): 1–10. http://dx.doi.org/10.4061/2011/230542.
Full textAbstract:
DNA topoisomerases of kinetoplastids represent a family of DNA processing enzymes that essentially solve the topological problems not only in nuclear DNA but also in kinetoplast DNA. We have, for the first time, identified a Leishmania donovani homologue of bacterial and eukaryotic IA type of topoisomerase III protein and termed as LdTopIIIβ. Complementation study of wild-type and mutant LdTopIIIβ with slow-growing topoisomerase III mutant yeast S. cerevisiae revealed the functional conservation of the leishmanial counterpart of topoisomerase IIIβ protein, the 327 tyrosine being the active site amino acid. A C-terminal deletion construct of LdTopIIIβ could not suppress the slow-growth phenotype of mutant yeast, indicating the requirement of C-terminal region for the enzyme function in vivo. LdTopIIIβ localized inside the nucleus and kinetoplast of the parasite. Taken together, our study indicates functional conservation and possible role of LdTopIIIβ in parasite DNA processing.
35
Cooper, Sinclair, Elizabeth S. Wadsworth, Torsten Ochsenreiter, Alasdair Ivens, Nicholas J. Savill, and Achim Schnaufer. "Assembly and annotation of the mitochondrial minicircle genome of a differentiation-competent strain of Trypanosoma brucei." Nucleic Acids Research 47, no. 21 (October 30, 2019): 11304–25. http://dx.doi.org/10.1093/nar/gkz928.
Full textAbstract:
Abstract Kinetoplastids are protists defined by one of the most complex mitochondrial genomes in nature, the kinetoplast. In the sleeping sickness parasite Trypanosoma brucei, the kinetoplast is a chain mail-like network of two types of interlocked DNA molecules: a few dozen ∼23-kb maxicircles (homologs of the mitochondrial genome of other eukaryotes) and thousands of ∼1-kb minicircles. Maxicircles encode components of respiratory chain complexes and the mitoribosome. Several maxicircle-encoded mRNAs undergo extensive post-transcriptional RNA editing via addition and deletion of uridines. The process is mediated by hundreds of species of minicircle-encoded guide RNAs (gRNAs), but the precise number of minicircle classes and gRNA genes was unknown. Here we present the first essentially complete assembly and annotation of the kinetoplast genome of T. brucei. We have identified 391 minicircles, encoding not only ∼930 predicted ‘canonical’ gRNA genes that cover nearly all known editing events (accessible via the web at http://hank.bio.ed.ac.uk), but also ∼370 ‘non-canonical’ gRNA genes of unknown function. Small RNA transcriptome data confirmed expression of the majority of both categories of gRNAs. Finally, we have used our data set to refine definitions for minicircle structure and to explore dynamics of minicircle copy numbers.
36
Harmer, Jane, Vyacheslav Yurchenko, Anna Nenarokova, Julius Lukeš, and Michael L. Ginger. "Farming, slaving and enslavement: histories of endosymbioses during kinetoplastid evolution." Parasitology 145, no. 10 (June 13, 2018): 1311–23. http://dx.doi.org/10.1017/s0031182018000781.
Full textAbstract:
AbstractParasitic trypanosomatids diverged from free-living kinetoplastid ancestors several hundred million years ago. These parasites are relatively well known, due in part to several unusual cell biological and molecular traits and in part to the significance of a few – pathogenic Leishmania and Trypanosoma species – as aetiological agents of serious neglected tropical diseases. However, the majority of trypanosomatid biodiversity is represented by osmotrophic monoxenous parasites of insects. In two lineages, novymonads and strigomonads, osmotrophic lifestyles are supported by cytoplasmic endosymbionts, providing hosts with macromolecular precursors and vitamins. Here we discuss the two independent origins of endosymbiosis within trypanosomatids and subsequently different evolutionary trajectories that see entrainment vs tolerance of symbiont cell divisions cycles within those of the host. With the potential to inform on the transition to obligate parasitism in the trypanosomatids, interest in the biology and ecology of free-living, phagotrophic kinetoplastids is beginning to enjoy a renaissance. Thus, we take the opportunity to additionally consider the wider relevance of endosymbiosis during kinetoplastid evolution, including the indulged lifestyle and reductive evolution of basal kinetoplastid Perkinsela.
37
Durrani, Hina, Marshall Hampton, Jon N. Rumbley, and Sara L. Zimmer. "A Global Analysis of Enzyme Compartmentalization to Glycosomes." Pathogens 9, no. 4 (April 12, 2020): 281. http://dx.doi.org/10.3390/pathogens9040281.
Full textAbstract:
In kinetoplastids, the first seven steps of glycolysis are compartmentalized into a glycosome along with parts of other metabolic pathways. This organelle shares a common ancestor with the better-understood eukaryotic peroxisome. Much of our understanding of the emergence, evolution, and maintenance of glycosomes is limited to explorations of the dixenous parasites, including the enzymatic contents of the organelle. Our objective was to determine the extent that we could leverage existing studies in model kinetoplastids to determine the composition of glycosomes in species lacking evidence of experimental localization. These include diverse monoxenous species and dixenous species with very different hosts. For many of these, genome or transcriptome sequences are available. Our approach initiated with a meta-analysis of existing studies to generate a subset of enzymes with highest evidence of glycosome localization. From this dataset we extracted the best possible glycosome signal peptide identification scheme for in silico identification of glycosomal proteins from any kinetoplastid species. Validation suggested that a high glycosome localization score from our algorithm would be indicative of a glycosomal protein. We found that while metabolic pathways were consistently represented across kinetoplastids, individual proteins within those pathways may not universally exhibit evidence of glycosome localization.
38
BATISTA, D. G. J., M. G. O. PACHECO, A. KUMAR, D. BRANOWSKA, M. A. ISMAIL, L. HU, D. W. BOYKIN, and M. N. C. SOEIRO. "Biological, ultrastructural effect and subcellular localization of aromatic diamidines in Trypanosoma cruzi." Parasitology 137, no. 2 (September 21, 2009): 251–59. http://dx.doi.org/10.1017/s0031182009991223.
Full textAbstract:
SUMMARYNo vaccines or safe chemotherapy are available for Chagas disease. Pentamidine and related di-cations are DNA minor groove-binders with broad-spectrum anti-protozoal activity. Therefore our aim was to evaluate the in vitro efficacy of di-cationic compounds – DB1645, DB1582, DB1651, DB1646, DB1670 and DB1627 – against bloodstream trypomastigotes (BT) and intracellular forms of Trypanosoma cruzi. Cellular targets of these compounds in treated parasites were also analysed by fluorescence and transmission electron microscopy (TEM). DB1645, DB1582 and DB1651 were the most active against BT showing IC50 values ranging between 0·15 and 6·9 μm. All compounds displayed low toxicity towards mammalian cells and DB1645, DB1582 and DB1651 were also the most effective against intracellular parasites, with IC50 values ranging between 7·3 and 13·3 μm. All compounds localized in parasite nuclei and kDNA (with greater intensity in the latter structure), and DB1582 and DB1651 also concentrated in non-DNA-containing cytoplasmic organelles possibly acidocalcisomes. TEM revealed alterations in mitochondria and kinetoplasts, as well as important disorganization of microtubules. Our data provide further information regarding the activity of this class of compounds upon T. cruzi which should aid future design and synthesis of agents that could be used for Chagas disease therapy.
39
Van den Kerkhof, Magali, Yann Sterckx, Philippe Leprohon, Louis Maes, and Guy Caljon. "Experimental Strategies to Explore Drug Action and Resistance in Kinetoplastid Parasites." Microorganisms 8, no. 6 (June 24, 2020): 950. http://dx.doi.org/10.3390/microorganisms8060950.
Full textAbstract:
Kinetoplastids are the causative agents of leishmaniasis, human African trypanosomiasis, and American trypanosomiasis. They are responsible for high mortality and morbidity in (sub)tropical regions. Adequate treatment options are limited and have several drawbacks, such as toxicity, need for parenteral administration, and occurrence of treatment failure and drug resistance. Therefore, there is an urgency for the development of new drugs. Phenotypic screening already allowed the identification of promising new chemical entities with anti-kinetoplastid activity potential, but knowledge on their mode-of-action (MoA) is lacking due to the generally applied whole-cell based approach. However, identification of the drug target is essential to steer further drug discovery and development. Multiple complementary techniques have indeed been used for MoA elucidation. In this review, the different ‘omics’ approaches employed to define the MoA or mode-of-resistance of current reference drugs and some new anti-kinetoplastid compounds are discussed.
40
Ziemniczak, Henrique Momo, Guilherme Henrique Lemes da Silva, Maerle Oliveira Maia, Elvino Ferreira, Klaus Casaro Saturnino, and Thaís Rabelo dos Santos-Doni. "Canine visceral leishmaniasis in Rondônia, Brazil: a report of an autochthonous case." Acta Veterinaria Brasilica 15, no. 1 (March 31, 2021): 15–18. http://dx.doi.org/10.21708/avb.2021.15.1.9422.
Full textAbstract:
Visceral Leishmaniasis (VL), also known as kala-azar, is a disseminated protozoan infection caused by the Leishmania donovani complex. Traditionally, the definitive diagnosis is made by detecting amastigotes in biological tissue samples. In August 2015, an apparently healthy, young adult, female, mongrel dog from the Zoonosis Control Center of the Rolim de Moura,Rondônia, was subjected to the canine visceral leishmaniasis diagnosis. The diagnosis was conducted using bone marrow aspirate smears and popliteal lymph node smears by Fine-needle aspiration biopsy (FNAB); stained slides with Diff-Quick screened for Leishmania amastigotes by means of direct optical microscopic examination (100×). Lymph node and bone marrow aspirates were used to investigate the presence of Leishmania infantum chagasi DNA by real-time PCR. The popliteal lymph node positive result was observed in typical amastigotes, presenting nucleus and kinetoplasts associated with lymphoblastic proliferation, reactive macrophages, plasmocytes (commonly Mott cells), eosinophils, and lymphoglandular hyperplasia. A positive bone marrow sample resulted from the observation of amastigotes in the monocyte cytoplasm or free on the smear background. The presence of the L. infantum kDNA was detected in lymph node and bone marrow FNAB samples. This research note describes the autochthonous case of CVL recorded in the state of Rondônia, Brazil, a non-endemic area for VL. According to the data, future studies must include a larger number of animals to elucidate the parasite’s epidemiological resource in Rondônia.
41
MADEIRA, M. F., M. A. SOUSA, J. H. S. BARROS, F. B. FIGUEIREDO, A. FAGUNDES, A. SCHUBACH, C. C. DE PAULA, et al. "Trypanosoma caninum n. sp. (Protozoa: Kinetoplastida) isolated from intact skin of a domestic dog (Canis familiaris) captured in Rio de Janeiro, Brazil." Parasitology 136, no. 4 (February 16, 2009): 411–23. http://dx.doi.org/10.1017/s003118200900554x.
Full textAbstract:
SUMMARYAn unknown Trypanosoma species was isolated from an axenic culture of intact skin from a domestic dog captured in Rio de Janeiro, Brazil, which was co-infected with Leishmania (Viannia) braziliensis. Giemsa-stained smears of cultures grown in different media revealed the presence of epimastigotes, trypomastigotes, spheromastigotes, transitional stages, and dividing forms (epimastigotes or spheromastigotes). The highest frequency of trypomastigotes was observed in RPMI (15·2%) and DMEM (9·2%) media containing 5% FCS, with a mean length of these forms of 43·0 and 36·0 μm, respectively. Molecular analysis by sequential application of PCR assays indicated that this trypanosome differs from Trypanosoma cruzi and T. rangeli when specific primers were applied. On the other hand, a PCR strategy targeted to the D7 domain of 24sα rDNA, using primers D75/D76, amplified products of about 250 bp in that isolate (stock A-27), different from the amplification products obtained with T. cruzi and T. rangeli. This organism differs from T. cruzi mainly by the size of its trypomastigote forms and kinetoplasts and the absence of infectivity for macrophages and triatomine bugs. It is also morphologically distinct from salivarian trypanosomes reported in Brazil. Isoenzyme analysis at 8 loci demonstrated a very peculiar banding pattern clearly distinct from those of T. rangeli and T. cruzi. We conclude that this isolate is a new Trypanosoma species. The name T. caninum is suggested.
42
Silva, C. F., M. B. Meuser, E. M. De Souza, M. N. L. Meirelles, C. E. Stephens, P. Som, D. W. Boykin, and M. N. C. Soeiro. "Cellular Effects of Reversed Amidines on Trypanosoma cruzi." Antimicrobial Agents and Chemotherapy 51, no. 11 (August 13, 2007): 3803–9. http://dx.doi.org/10.1128/aac.00047-07.
Full textAbstract:
ABSTRACT Aromatic diamidines represent a class of DNA minor groove-binding ligands that exhibit high levels of antiparasitic activity. Since the chemotherapy for Chagas' disease is still an unsolved problem and previous reports on diamidines and related analogues show that they have high levels of activity against Trypanosoma cruzi infection both in vitro and in vivo, our present aim was to evaluate the cellular effects in vitro of three reversed amidines (DB889, DB702, and DB786) and one diguanidine (DB711) against both amastigotes and bloodstream trypomastigotes of T. cruzi, the etiological agent of Chagas ' disease. Our data show that the reversed amidines have higher levels of activity than the diguanidine, with the order of trypanocidal activities being as follows: DB889 > DB702 > DB786 > DB711. Transmission electron microscopy analysis showed that the reversed amidines induced many alterations in the nuclear morphology, swelling of the endoplasmic reticulum and Golgi structures, and consistent damage in the mitochondria and kinetoplasts of the parasites. Interestingly, in trypomastigotes treated with the reversed amidine DB889, multiple axoneme structures (flagellar microtubules) were noted. Flow cytometry analysis confirmed that the treated parasites presented an important loss of the mitochondrial membrane potential, as revealed by a decrease in rhodamine 123 fluorescence. Our results show that the reversed amidines have promising activities against the relevant mammalian forms of T. cruzi and display high trypanocidal effects at very low doses. This is especially the case for DB889, which merits further in vivo evaluation.
43
Hayes, Polly, Vladimir Varga, Sofia Olego-Fernandez, Jack Sunter, Michael L. Ginger, and Keith Gull. "Modulation of a cytoskeletal calpain-like protein induces major transitions in trypanosome morphology." Journal of Cell Biology 206, no. 3 (August 4, 2014): 377–84. http://dx.doi.org/10.1083/jcb.201312067.
Full textAbstract:
Individual eukaryotic microbes, such as the kinetoplastid parasite Trypanosoma brucei, have a defined size, shape, and form yet transition through life cycle stages, each having a distinct morphology. In questioning the structural processes involved in these transitions, we have identified a large calpain-like protein that contains numerous GM6 repeats (ClpGM6) involved in determining T. brucei cell shape, size, and form. ClpGM6 is a cytoskeletal protein located within the flagellum along the flagellar attachment zone (FAZ). Depletion of ClpGM6 in trypomastigote forms produces cells with long free flagella and a shorter FAZ, accompanied by repositioning of the basal body, the kinetoplast, Golgi, and flagellar pocket, reflecting an epimastigote-like morphology. Hence, major changes in microbial cell form can be achieved by simple modulation of one or a few proteins via coordinated association and positioning of membrane and cytoskeletal components.
44
Belaunzarán, María Laura, Estela María Lammel, and Elvira Luisa Durante de Isola. "Phospholipases A in Trypanosomatids." Enzyme Research 2011 (April 5, 2011): 1–10. http://dx.doi.org/10.4061/2011/392082.
Full textAbstract:
Phospholipases are a complex and important group of enzymes widespread in nature, that play crucial roles in diverse biochemical processes and are classified as A1, A2, C, and D. Phospholipases A1 and A2 activities have been linked to pathogenesis in various microorganisms, and particularly in pathogenic protozoa they have been implicated in cell invasion. Kinetoplastids are a group of flagellated protozoa, including extra- and intracellular parasites that cause severe disease in humans and animals. In the present paper, we will mainly focus on the three most important kinetoplastid human pathogens, Trypanosoma brucei, Trypanosoma cruzi, and Leishmania spp., giving a perspective of the research done up to now regarding biochemical, biological, and molecular characteristics of Phospholipases A1 and A2 and their contribution to pathogenesis.
45
Dofuor, Aboagye Kwarteng, Temitayo Samson Ademolue, Cynthia Mmalebna Amisigo, Kwaku Kyeremeh, and Theresa Manful Gwira. "Chemical Derivatization and Characterization of Novel Antitrypanosomals for African Trypanosomiasis." Molecules 26, no. 15 (July 25, 2021): 4488. http://dx.doi.org/10.3390/molecules26154488.
Full textAbstract:
The search for novel antitrypanosomals and the investigation into their mode of action remain crucial due to the toxicity and resistance of commercially available antitrypanosomal drugs. In this study, two novel antitrypanosomals, tortodofuordioxamide (compound 2) and tortodofuorpyramide (compound 3), were chemically derived from the natural N-alkylamide tortozanthoxylamide (compound 1) through structural modification. The chemical structures of these compounds were confirmed through spectrometric and spectroscopic analysis, and their in vitro efficacy and possible mechanisms of action were, subsequently, investigated in Trypanosoma brucei (T. brucei), one of the causative species of African trypanosomiasis (AT). The novel compounds 2 and 3 displayed significant antitrypanosomal potencies in terms of half-maximal effective concentrations (EC50) and selectivity indices (SI) (compound 1, EC50 = 7.3 μM, SI = 29.5; compound 2, EC50 = 3.2 μM, SI = 91.3; compound 3, EC50 = 4.5 μM, SI = 69.9). Microscopic analysis indicated that at the EC50 values, the compounds resulted in the coiling and clumping of parasite subpopulations without significantly affecting the normal ratio of nuclei to kinetoplasts. In contrast to the animal antitrypanosomal drug diminazene, compounds 1, 2 and 3 exhibited antioxidant absorbance properties comparable to the standard antioxidant Trolox (Trolox, 0.11 A; diminazene, 0.50 A; compound 1, 0.10 A; compound 2, 0.09 A; compound 3, 0.11 A). The analysis of growth kinetics suggested that the compounds exhibited a relatively gradual but consistent growth inhibition of T. brucei at different concentrations. The results suggest that further pharmacological optimization of compounds 2 and 3 may facilitate their development into novel AT chemotherapy.
46
Engel, Juan C., Kenny K. H. Ang, Steven Chen, Michelle R. Arkin, James H. McKerrow, and Patricia S. Doyle. "Image-Based High-Throughput Drug Screening Targeting the Intracellular Stage of Trypanosoma cruzi, the Agent of Chagas' Disease." Antimicrobial Agents and Chemotherapy 54, no. 8 (June 14, 2010): 3326–34. http://dx.doi.org/10.1128/aac.01777-09.
Full textAbstract:
ABSTRACT Chagas' disease, caused by infection with the parasite Trypanosoma cruzi, is the major cause of heart failure in Latin America. Classic clinical manifestations result from the infection of heart muscle cells leading to progressive cardiomyopathy. To ameliorate disease, chemotherapy must eradicate the parasite. Current drugs are ineffective and toxic, and new therapy is a critical need. To expedite drug screening for this neglected disease, we have developed and validated a cell-based, high-throughput assay that can be used with a variety of untransfected T. cruzi isolates and host cells and that simultaneously measures efficacy against the intracellular amastigote stage and toxicity to host cells. T. cruzi-infected muscle cells were incubated in 96-well plates with test compounds. Assay plates were automatically imaged and analyzed based on size differences between the DAPI (4′,6-diamidino-2-phenylindole)-stained host cell nuclei and parasite kinetoplasts. A reduction in the ratio of T. cruzi per host cell provided a quantitative measure of parasite growth inhibition, while a decrease in count of the host nuclei indicated compound toxicity. The assay was used to screen a library of clinically approved drugs and identified 55 compounds with activity against T. cruzi. The flexible assay design allows the use of various parasite strains, including clinical isolates with different biological characteristics (e.g., tissue tropism and drug sensitivity), and a broad range of host cells and may even be adapted to screen for inhibitors against other intracellular pathogens. This high-throughput assay will have an important impact in antiparasitic drug discovery.
47
Mwangi, Harrison Ndung’u, Edward Kirwa Muge, Peter Waiganjo Wagacha, Albert Ndakala, and Francis Jackim Mulaa. "Methods for Identifying Microbial Natural Product Compounds that Target Kinetoplastid RNA Structural Motifs by Homology and De Novo Modeled 18S rRNA." International Journal of Molecular Sciences 22, no. 9 (April 26, 2021): 4493. http://dx.doi.org/10.3390/ijms22094493.
Full textAbstract:
The development of novel anti-infectives against Kinetoplastids pathogens targeting proteins is a big problem occasioned by the antigenic variation in these parasites. This is also a global concern due to the zoonosis of these parasites, as they infect both humans and animals. Therefore, we need not only to create novel antibiotics, but also to speed up the development pipeline for these antibiotics. This may be achieved by using novel drug targets for Kinetoplastids drug discovery. In this study, we focused our attention on motifs of rRNA molecules that have been created using homology modeling. The RNA is the most ambiguous biopolymer in the kinetoplatid, which carries many different functions. For instance, tRNAs, rRNAs, and mRNAs are essential for gene expression both in the pro-and eukaryotes. However, all these types of RNAs have sequences with unique 3D structures that are specific for kinetoplastids only and can be used to shut down essential biochemical processes in kinetoplastids only. All these features make RNA very potent targets for antibacterial drug development. Here, we combine in silico methods combined with both computational biology and structure prediction tools to address our hypothesis. In this study, we outline a systematic approach for identifying kinetoplastid rRNA-ligand interactions and, more specifically, techniques that can be used to identify small molecules that target particular RNA. The high-resolution optimized model structures of these kineoplastids were generated using RNA 123, where all the stereochemical conflicts were solved and energies minimized to attain the best biological qualities. The high-resolution optimized model’s structures of these kinetoplastids were generated using RNA 123 where all the stereochemical conflicts were solved and energies minimized to attain the best biological qualities. These models were further analyzed to give their docking assessment reliability. Docking strategies, virtual screening, and fishing approaches successfully recognized novel and myriad macromolecular targets for the myxobacterial natural products with high binding affinities to exploit the unmet therapeutic needs. We demonstrate a sensible exploitation of virtual screening strategies to 18S rRNA using natural products interfaced with classical maximization of their efficacy in phamacognosy strategies that are well established. Integration of these virtual screening strategies in natural products chemistry and biochemistry research will spur the development of potential interventions to these tropical neglected diseases.
48
Harada, Ryo, Yoshihisa Hirakawa, Akinori Yabuki, Yuichiro Kashiyama, Moe Maruyama, Ryo Onuma, Petr Soukal, et al. "Inventory and Evolution of Mitochondrion-localized Family A DNA Polymerases in Euglenozoa." Pathogens 9, no. 4 (April 1, 2020): 257. http://dx.doi.org/10.3390/pathogens9040257.
Full textAbstract:
The order Trypanosomatida has been well studied due to its pathogenicity and the unique biology of the mitochondrion. In Trypanosoma brucei, four DNA polymerases, namely PolIA, PolIB, PolIC, and PolID, related to bacterial DNA polymerase I (PolI), were shown to be localized in mitochondria experimentally. These mitochondrion-localized DNA polymerases are phylogenetically distinct from other family A DNA polymerases, such as bacterial PolI, DNA polymerase gamma (Polγ) in human and yeasts, “plant and protist organellar DNA polymerase (POP)” in diverse eukaryotes. However, the diversity of mitochondrion-localized DNA polymerases in Euglenozoa other than Trypanosomatida is poorly understood. In this study, we discovered putative mitochondrion-localized DNA polymerases in broad members of three major classes of Euglenozoa—Kinetoplastea, Diplonemea, and Euglenida—to explore the origin and evolution of trypanosomatid PolIA-D. We unveiled distinct inventories of mitochondrion-localized DNA polymerases in the three classes: (1) PolIA is ubiquitous across the three euglenozoan classes, (2) PolIB, C, and D are restricted in kinetoplastids, (3) new types of mitochondrion-localized DNA polymerases were identified in a prokinetoplastid and diplonemids, and (4) evolutionarily distinct types of POP were found in euglenids. We finally propose scenarios to explain the inventories of mitochondrion-localized DNA polymerases in Kinetoplastea, Diplonemea, and Euglenida.
49
Eresh, S., S. M. McCallum, and D. C. Barker. "Identification and diagnosis of Leishmania mexicana complex isolates by polymerase chain reaction." Parasitology 109, no. 4 (November 1994): 423–33. http://dx.doi.org/10.1017/s0031182000080677.
Full textAbstract:
SUMMARYFollowing cloning of Leishmania (L.) amazonensis kinetoplast DNA two recombinant clones were identified: one specific for L. (L.) amazonensis and the other specific for L. (L.) amazonensis and closely related isolates. DNA sequences from these clones were compared with those of other kinetoplastids and oligonucleotide primers were designed to be used in the polymerase chain reaction. A pair of these primers has been shown not only to be highly specific for L. mexicana complex isolates but can also be used to distinguish between L. (L.) mexicana and L. (L.) amazonensis isolates. These primers have been tested with water-lysed cultures, crude DNA extracts from human patients, potential host reservoirs, sandfly vectors and with cell pellets after isoenzyme characterization. The results of these tests indicate that the primers can be used specifically in the presence of excess host DNA originating from the majority of South American countries.
50
FIGUEROA, FELIPE, WERNER E. MAYER, JIŘÍ LOM, IVA DYKOVÁ, MATHIAS WELLER, HANA PECKOVA, and JAN KLEIN. "Fish Trypanosomes: Their Position in Kinetoplastid Phylogeny and Variability as Determined from 12S rRNA Kinetoplast Sequences." Journal of Eukaryotic Microbiology 46, no. 5 (September 1999): 473–81. http://dx.doi.org/10.1111/j.1550-7408.1999.tb06064.x.
Full text