RESUMEN
The class Kinetoplastea encompasses both free-living and parasitic species from a wide range of hosts. Several representatives of this group are responsible for severe human diseases and for economic losses in agriculture and livestock. While this group encompasses over 30 genera, most of the available information has been derived from the vertebrate pathogenic genera Leishmaniaand Trypanosoma. Recent studies of the previously neglected groups of Kinetoplastea indicated that the actual diversity is much higher than previously thought. This article discusses the known segment of kinetoplastid diversity and how gene-directed Sanger sequencing and next-generation sequencing methods can help to deepen our knowledge of these interesting protists.
Asunto(s)
Biodiversidad , ADN Protozoario/genética , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Kinetoplastida/genética , Filogenia , ARN Protozoario/genética , Biomarcadores , Biología Computacional , Bases de Datos Genéticas , Código de Barras del ADN Taxonómico/tendencias , Ambiente , Kinetoplastida/clasificación , Kinetoplastida/citología , Metagenómica/tendencias , /genéticaRESUMEN
Early immunological data, obtained by immunodiffusion and immunoelectrophoresis, on the whole-cell antigenicity of kinetoplastid protozoa were retrieved and used to construct a dendrogram of antigenic distances. Remarkably, they supported the same taxonomic conclusions as analyses based on DNA and protein sequence data.
Asunto(s)
Antígenos de Protozoos/genética , Kinetoplastida/clasificación , Antígenos de Protozoos/inmunología , Inmunodifusión , Inmunoelectroforesis , Kinetoplastida/genética , Kinetoplastida/inmunologíaRESUMEN
Since the discovery that genes are split into intron and exons, the studies of the mechanisms involved in splicing pointed to presence of consensus signals in an attempt to generalize the process for all living cells. However, as discussed in the present review, splicing is a theme full of variations. The trans-splicing of pre-mRNAs, the joining of exons from distinct transcripts, is one of these variations with broad distribution in the phylogenetic tree. The biological meaning of this phenomenon is discussed encompassing reactions resembling a possible noise to mechanisms of gene expression regulation. All of them however, can contribute to the generation of life diversity.
Asunto(s)
Animales , Variación Genética , Kinetoplastida/genética , Mamíferos/genética , Nematodos/genética , Precursores del ARN/genética , Trans-Empalme/genética , Regulación de la Expresión Génica , FilogeniaRESUMEN
To further investigate phylogeny of kinetoplastid protozoa, the sequences of small subunit (18S) ribosomal RNA of nine bodonid isolates and ten isolates of insect trypanosomatids have been determined. The root of the kinetoplastid tree was attached to the branch of Bodo designis and/or Cruzella marina. The suborder Trypanosomatina appeared as a monophyletic group, while the suborder Bodonina was paraphyletic. Among bodonid lineages, parasitic organisms were intermingled with free-living ones, implying multiple transitions to parasitism and supporting the `vertebrate-first hypothesis'. The tree indicated that the genera Cryptobia and Bodo are artificial taxa. Separation of fish cryptobias and Trypanoplasma borreli as different genera was not supported. In trypanosomatids, the genera Leptomonas and Blastocrithidia were polyphyletic, similar to the genera Herpetomonas and Crithidia and in contrast to the monophyletic genera Trypanosoma and Phytomonas. This analysis has shown that the morphological classification of kinetoplastids does not in general reflect their genetic affinities and needs a revision