The Experts below are selected from a list of 5211 Experts worldwide ranked by ideXlab platform
Kyungil Park - One of the best experts on this subject based on the ideXlab platform.
-
the Kinetoplastid parasite azumiobodo hoyamushi the causative agent of soft tunic syndrome of the sea squirt halocynthia roretzi resides in the east sea of korea
Journal of Invertebrate Pathology, 2014Co-Authors: Jong Soo Park, Kwan Ha Park, Yunkyung Shin, Kyungil ParkAbstract:Abstract Mass mortality of the edible sea squirt Halocynthia roretzi since the 1990s in the southern and eastern seas of Korea has caused large economic losses. The disease is characterized by symptoms of initially softened and thinned tunics that eventually rupture. Thus, the disease is called soft tunic syndrome (STS); however, the causative agent in these regions is unknown. In the present study, two Kinetoplastid organisms were isolated from STS sea squirts collected from culture farms in Tongyeong located in the East Sea of Korea. Phylogenetic analysis of 18S rRNA sequences identified these organisms as Azumiobodo hoyamushi and Procryptobia sorokini. These Kinetoplastids were injected into healthy sea squirts and cultured at 15 °C for 13 days. Sea squirts injected with A. hoyamushi showed 100% STS whereas, P. sorokini did not induce disease, thereby confirming A. hoyamushi as the causative agent of STS. A. hoyamushi flourishes in vitro at 10–15 °C, and dies at temperatures below 5 °C or above 20 °C. The optimum salinity level for growth is 30–35 psu, and death occurs below 25 psu. These optima coincide with marine temperature and salinity levels between March and June on the southern coasts of Korea, the period when the syndrome occurs at the highest frequency. The identification here of A. hoyamushi as the causative agent of STS and our findings regarding its optimum growth conditions should lead to methods for reducing the incidence of STS.
Julius Lukes - One of the best experts on this subject based on the ideXlab platform.
-
farming slaving and enslavement histories of endosymbioses during Kinetoplastid evolution
Parasitology, 2018Co-Authors: Jane Harmer, Julius Lukes, Vyacheslav Yurchenko, Anna Nenarokova, Michael L GingerAbstract:Parasitic 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.
-
Neobodonids are dominant Kinetoplastids in the global ocean.
Environmental Microbiology, 2018Co-Authors: Olga Flegontova, Julius Lukes, Pavel Flegontov, Shruti Malviya, Julie Poulain, Colomban De Vargas, Chris Bowler, Aleš HorákAbstract:: Kinetoplastid flagellates comprise basal mostly free-living bodonids and derived obligatory parasitic trypanosomatids, which belong to the best-studied protists. Due to their omnipresence in aquatic environments and soil, the bodonids are of ecological significance. Here, we present the first global survey of marine Kinetoplastids and compare it with the strikingly different patterns of abundance and diversity in their sister clade, the diplonemids. Based on analysis of 18S rDNA V9 ribotypes obtained from 124 sites sampled during the Tara Oceans expedition, our results show generally low to moderate abundance and diversity of planktonic Kinetoplastids. Although we have identified all major Kinetoplastid lineages, 98% of Kinetoplastid reads are represented by neobodonids, namely specimens of the Neobodo and Rhynchomonas genera, which make up 59% and 18% of all reads, respectively. Most Kinetoplastids have small cell size (0.8-5 µm) and tend to be more abundant in the mesopelagic as compared to the euphotic zone. Some of the most abundant operational taxonomic units have distinct geographical distributions, and three novel putatively parasitic neobodonids were identified, along with their potential hosts.
-
Heme pathway evolution in Kinetoplastid protists
BMC Evolutionary Biology, 2016Co-Authors: Ugo Cenci, Julius Lukes, Daniel Moog, Bruce A. Curtis, Goro Tanifuji, John M. ArchibaldAbstract:Background Kinetoplastea is a diverse protist lineage composed of several of the most successful parasites on Earth, organisms whose metabolisms have coevolved with those of the organisms they infect. Parasitic Kinetoplastids have emerged from free-living, non-pathogenic ancestors on multiple occasions during the evolutionary history of the group. Interestingly, in both parasitic and free-living Kinetoplastids, the heme pathway—a core metabolic pathway in a wide range of organisms—is incomplete or entirely absent. Indeed, Kinetoplastea investigated thus far seem to bypass the need for heme biosynthesis by acquiring heme or intermediate metabolites directly from their environment. Results Here we report the existence of a near-complete heme biosynthetic pathway in Perkinsela spp., Kinetoplastids that live as obligate endosymbionts inside amoebozoans belonging to the genus Paramoeba / Neoparamoeba . We also use phylogenetic analysis to infer the evolution of the heme pathway in Kinetoplastea. Conclusion We show that Perkinsela spp. is a deep-branching Kinetoplastid lineage, and that lateral gene transfer has played a role in the evolution of heme biosynthesis in Perkinsela spp. and other Kinetoplastea. We also discuss the significance of the presence of seven of eight heme pathway genes in the Perkinsela genome as it relates to its endosymbiotic relationship with Paramoeba .
-
Heme pathway evolution in Kinetoplastid protists
BMC Evolutionary Biology, 2016Co-Authors: Ugo Cenci, Julius Lukes, Daniel Moog, Bruce A. Curtis, Goro Tanifuji, John M. ArchibaldAbstract:Background Kinetoplastea is a diverse protist lineage composed of several of the most successful parasites on Earth, organisms whose metabolisms have coevolved with those of the organisms they infect. Parasitic Kinetoplastids have emerged from free-living, non-pathogenic ancestors on multiple occasions during the evolutionary history of the group. Interestingly, in both parasitic and free-living Kinetoplastids, the heme pathway—a core metabolic pathway in a wide range of organisms—is incomplete or entirely absent. Indeed, Kinetoplastea investigated thus far seem to bypass the need for heme biosynthesis by acquiring heme or intermediate metabolites directly from their environment.
-
evolution of parasitism in Kinetoplastid flagellates
Molecular and Biochemical Parasitology, 2014Co-Authors: Julius Lukes, Tomas Skalický, Jan Votýpka, Vyacheslav YurchenkoAbstract:a b s t r a c t Kinetoplastid protists offer a unique opportunity for studying the evolution of parasitism. While all their close relatives are either photo- or phagotrophic, a number of Kinetoplastid species are facultative or obligatory parasites, supporting a hypothesis that parasitism has emerged within this group of flagellates. In this review we discuss origin and evolution of parasitism in bodonids and trypanosomatids and specific adaptations allowing these protozoa to co-exist with their hosts. We also explore the limits of biodiversity of monoxenous (one host) trypanosomatids and some features distinguishing them from their dixenous
Bungo Akiyoshi - One of the best experts on this subject based on the ideXlab platform.
-
the Kinetoplastid kinetochore protein kkt4 is an unconventional microtubule tip coupling protein
Journal of Cell Biology, 2018Co-Authors: Aida Llauro, Hanako Hayashi, Megan E Bailey, Alexander C Wilson, Patryk Ludzia, Charles L Asbury, Bungo AkiyoshiAbstract:: Kinetochores are multiprotein machines that drive chromosome segregation by maintaining persistent, load-bearing linkages between chromosomes and dynamic microtubule tips. Kinetochores in commonly studied eukaryotes bind microtubules through widely conserved components like the Ndc80 complex. However, in evolutionarily divergent Kinetoplastid species such as Trypanosoma brucei, which causes sleeping sickness, the kinetochores assemble from a unique set of proteins lacking homology to any known microtubule-binding domains. Here, we show that the T. brucei kinetochore protein KKT4 binds directly to microtubules and maintains load-bearing attachments to both growing and shortening microtubule tips. The protein localizes both to kinetochores and to spindle microtubules in vivo, and its depletion causes defects in chromosome segregation. We define a microtubule-binding domain within KKT4 and identify several charged residues important for its microtubule-binding activity. Thus, despite its lack of significant similarity to other known microtubule-binding proteins, KKT4 has key functions required for driving chromosome segregation. We propose that it represents a primary element of the kinetochore-microtubule interface in Kinetoplastids.
-
the unconventional Kinetoplastid kinetochore protein kkt4 tracks with dynamic microtubule tips
bioRxiv, 2017Co-Authors: Aida Llauro, Hanako Hayashi, Megan E Bailey, Alexander C Wilson, Patryk Ludzia, Charles L Asbury, Bungo AkiyoshiAbstract:Kinetochores are multiprotein machines that drive chromosome segregation in all eukaryotes by maintaining persistent, load-bearing linkages between the chromosomes and the tips of dynamic spindle microtubules. Kinetochores in commonly studied eukaryotes are assembled from widely conserved components like the Ndc80 complex that directly binds microtubules. However, in evolutionarily-divergent Kinetoplastid species such as Trypanosoma brucei, which causes sleeping sickness, the kinetochores assemble from a unique set of proteins lacking homology to any known microtubule-binding domains. Here we show that a kinetochore protein from T. brucei called KKT4 binds directly to microtubules, diffuses along the microtubule lattice, and tracks with disassembling microtubule tips. The protein localizes both to kinetochores and to spindle microtubules in vivo, and its depletion causes defects in chromosome segregation. We define a minimal microtubule-binding domain within KKT4 and identify several charged residues important for its microtubule-binding activity. Laser trapping experiments show that KKT4 can maintain load-bearing attachments to both growing and shortening microtubule tips. Thus, despite its lack of similarity to other known microtubule-binding proteins, KKT4 has key functions required for harnessing microtubule dynamics to drive chromosome segregation. We propose that it represents a primary element of the kinetochore-microtubule interface in Kinetoplastids.
-
divergent polo box domains underpin the unique Kinetoplastid kinetochore
Open Biology, 2016Co-Authors: Olga O Nerusheva, Bungo AkiyoshiAbstract:Kinetochores are macromolecular machines that drive eukaryotic chromosome segregation by interacting with centromeric DNA and spindle microtubules. While most eukaryotes possess conventional kinetochore proteins, evolutionarily distant Kinetoplastid species have unconventional kinetochore proteins, composed of at least 19 proteins (KKT1–19). Polo-like kinase (PLK) is not a structural kinetochore component in either system. Here, we report the identification of an additional kinetochore protein, KKT20, in Trypanosoma brucei . KKT20 has sequence similarity with KKT2 and KKT3 in the Cys-rich region, and all three proteins have weak but significant similarity to the polo box domain (PBD) of PLK. These divergent PBDs of KKT2 and KKT20 are sufficient for kinetochore localization in vivo . We propose that the ancestral PLK acquired a Cys-rich region and then underwent gene duplication events to give rise to three structural kinetochore proteins in Kinetoplastids.
-
Discovery of Unconventional Kinetochores in Kinetoplastids
Cell, 2014Co-Authors: Bungo Akiyoshi, Keith GullAbstract:The kinetochore is the macromolecular protein complex that directs chromosome segregation in eukaryotes. It has been widely assumed that the core kinetochore consists of proteins that are common to all eukaryotes. However, no conventional kinetochore components have been identified in any Kinetoplastid genome, thus challenging this assumption of universality. Here, we report the identification of 19 kinetochore proteins (KKT1–19) in Trypanosoma brucei. The majority is conserved among Kinetoplastids, but none of them has detectable homology to conventional kinetochore proteins. These proteins instead have a variety of features not found in conventional kinetochore proteins. We propose that Kinetoplastids build kinetochores using a distinct set of proteins. These findings provide important insights into the longstanding problem of the position of the root of the eukaryotic tree of life.
Jong Soo Park - One of the best experts on this subject based on the ideXlab platform.
-
the Kinetoplastid parasite azumiobodo hoyamushi the causative agent of soft tunic syndrome of the sea squirt halocynthia roretzi resides in the east sea of korea
Journal of Invertebrate Pathology, 2014Co-Authors: Jong Soo Park, Kwan Ha Park, Yunkyung Shin, Kyungil ParkAbstract:Abstract Mass mortality of the edible sea squirt Halocynthia roretzi since the 1990s in the southern and eastern seas of Korea has caused large economic losses. The disease is characterized by symptoms of initially softened and thinned tunics that eventually rupture. Thus, the disease is called soft tunic syndrome (STS); however, the causative agent in these regions is unknown. In the present study, two Kinetoplastid organisms were isolated from STS sea squirts collected from culture farms in Tongyeong located in the East Sea of Korea. Phylogenetic analysis of 18S rRNA sequences identified these organisms as Azumiobodo hoyamushi and Procryptobia sorokini. These Kinetoplastids were injected into healthy sea squirts and cultured at 15 °C for 13 days. Sea squirts injected with A. hoyamushi showed 100% STS whereas, P. sorokini did not induce disease, thereby confirming A. hoyamushi as the causative agent of STS. A. hoyamushi flourishes in vitro at 10–15 °C, and dies at temperatures below 5 °C or above 20 °C. The optimum salinity level for growth is 30–35 psu, and death occurs below 25 psu. These optima coincide with marine temperature and salinity levels between March and June on the southern coasts of Korea, the period when the syndrome occurs at the highest frequency. The identification here of A. hoyamushi as the causative agent of STS and our findings regarding its optimum growth conditions should lead to methods for reducing the incidence of STS.
Kwan Ha Park - One of the best experts on this subject based on the ideXlab platform.
-
the Kinetoplastid parasite azumiobodo hoyamushi the causative agent of soft tunic syndrome of the sea squirt halocynthia roretzi resides in the east sea of korea
Journal of Invertebrate Pathology, 2014Co-Authors: Jong Soo Park, Kwan Ha Park, Yunkyung Shin, Kyungil ParkAbstract:Abstract Mass mortality of the edible sea squirt Halocynthia roretzi since the 1990s in the southern and eastern seas of Korea has caused large economic losses. The disease is characterized by symptoms of initially softened and thinned tunics that eventually rupture. Thus, the disease is called soft tunic syndrome (STS); however, the causative agent in these regions is unknown. In the present study, two Kinetoplastid organisms were isolated from STS sea squirts collected from culture farms in Tongyeong located in the East Sea of Korea. Phylogenetic analysis of 18S rRNA sequences identified these organisms as Azumiobodo hoyamushi and Procryptobia sorokini. These Kinetoplastids were injected into healthy sea squirts and cultured at 15 °C for 13 days. Sea squirts injected with A. hoyamushi showed 100% STS whereas, P. sorokini did not induce disease, thereby confirming A. hoyamushi as the causative agent of STS. A. hoyamushi flourishes in vitro at 10–15 °C, and dies at temperatures below 5 °C or above 20 °C. The optimum salinity level for growth is 30–35 psu, and death occurs below 25 psu. These optima coincide with marine temperature and salinity levels between March and June on the southern coasts of Korea, the period when the syndrome occurs at the highest frequency. The identification here of A. hoyamushi as the causative agent of STS and our findings regarding its optimum growth conditions should lead to methods for reducing the incidence of STS.
