16S ribosomal DNA sequence identities of beta-proteobacterial endosymbionts in three Crithidia species

Du, Yubin; McLaughlin, Gerald L.; Chang, Kwang-Poo

doi:10.1128/jb.176.10.3081-3084.1994

Cited by 27 publications

(23 citation statements)

References 24 publications

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“…Currently, only four endosymbiotic micro-organisms pertaining to the β-Proteobacteria have been reported : Polynucleobacter necessarius, an endosymbiont of the hypotrichous ciliate Euplotes aediculatus (Springer et al, 1996) ; Kinetoplastibacterium crithidii and Kinetoplastibacterium blastocrithidii, which are obligate endosymbionts of the insect trypanosomatids Crithidia sp. and Blastocrithidia culicis, respectively (Du et al, 1994) ; and endosymbionts of the arbuscular-mycorrhizal fungus Gigaspora margarita (Bianciotto et al, 1996). The β-proteobacterial Acanthamoeba endosymbionts identified in this study and the other, distantly related currently recognized endosymbiotic bacteria within this subclass are members of different lines of descent (Fig.…”

Section: Classification Of the Novel β-Proteobacterial Endosymbionts mentioning

confidence: 99%

Obligate bacterial endosymbionts of Acanthamoeba spp. related to the beta-Proteobacteria: proposal of 'Candidatus Procabacter acanthamoebae' gen. nov., sp. nov.

Horn¹,

Fritsche²,

Linner³

et al. 2002

International Journal of Systematic and Evolutionary Microbiology

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Section: Classification Of the Novel β-Proteobacterial Endosymbionts mentioning

confidence: 99%

Obligate bacterial endosymbionts of Acanthamoeba spp. related to the beta-Proteobacteria: proposal of 'Candidatus Procabacter acanthamoebae' gen. nov., sp. nov.

Horn¹,

Fritsche²,

Linner³

et al. 2002

International Journal of Systematic and Evolutionary Microbiology

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“…The members of one particular group of trypanosomatid species (exemplified by Crithidia deanei, C. oncopelti, C. desouzai, Blastocrithidia culicis, and Herpetomonas roitmani) have been described as lacking a PFR (17). These species also share other ultrastructural features (17), the most obvious of which is possession of an enslaved endosymbiont bacterium (13), most probably the result of a single acquisition in the common ancestor of the above species. Surprisingly, these endosymbiont-harboring species are able to attach to the invertebrate host epithelia (15) and are actively motile (21,39).…”

mentioning

confidence: 99%

Cryptic Paraflagellar Rod in Endosymbiont-Containing Kinetoplastid Protozoa

et al. 2005

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

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“…The symbionts found in Crithidia and Blastocrithidia were thus designated, respectively, as Kinetoplastibacterium crithidii and Kinetoplastibacterium blastocrithidii. These microorganisms were grouped together with bacteria of the genera Bordetella, Neisseria and Eikenella, in the L division of Proteobacteria [18,19].…”

Section: Phylogenetic Classi¢cation Of the Endosymbionts And Their Homentioning

confidence: 99%

Endosymbiosis in protozoa of the Trypanosomatidae family

Souza¹

1999

FEMS Microbiology Letters

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A small number of trypanosomatids present bacterium endosymbionts in the cytoplasm, which divide synchronously with the host cell. Crithidia oncopleti, Crithidia deanei, Crithidia desouzai, Blastocrithidia culicis and Herpetomonas roitmani are the best characterized species. The endosymbiont is surrounded by two membranes separated from each other by an electronlucent space. The presence of the endosymbiont led to the appearance of morphological changes which include the lack of the paraflagellar rod associated to the axoneme, the morphology of the kinetoplast and the association of the sub-pellicular microtubules with portions of the protozoan plasma membrane. Aposymbiotic strains could be obtained by antibiotic treatment, opening the possibility to make comparative analysis of endosymbiont-containing an endosymbiont-free populations of the same species. It is clear that metabolic cycles are established between the prokaryiont and the host cell. The results obtained show that endosymbiont-containing species of trypanosomatids constitute an excellent model to study basic processes on the endosymbiont^host cell relationship and the origin of new organelles. z

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16S ribosomal DNA sequence identities of beta-proteobacterial endosymbionts in three Crithidia species

Cited by 27 publications

References 24 publications

Obligate bacterial endosymbionts of Acanthamoeba spp. related to the beta-Proteobacteria: proposal of 'Candidatus Procabacter acanthamoebae' gen. nov., sp. nov.

Obligate bacterial endosymbionts of Acanthamoeba spp. related to the beta-Proteobacteria: proposal of 'Candidatus Procabacter acanthamoebae' gen. nov., sp. nov.

Cryptic Paraflagellar Rod in Endosymbiont-Containing Kinetoplastid Protozoa

Endosymbiosis in protozoa of the Trypanosomatidae family

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