ABSTRACT In the past 10 years, number of endosymbionts described within bacterial order Rickettsiales has constantly grown. Since 2006, 18 novel genera inhabiting protists, such as ciliates and amoebae, have been described. this work, we characterize two from Paramecium collected near Bloomington, IN. Both endosymbiotic species inhabit cytoplasm same host. The Gram-negative bacterium “ Candidatus Bealeia paramacronuclearis” occurs in clumps is frequently associated with host macronucleus....

"Neglected Rickettsiaceae" (i.e. those harboured by non-hematophagous eukaryotic hosts) display greater phylogenetic variability and more widespread dispersal than pathogenic ones; yet, the knowledge about their actual host range shift mechanism is scarce. The present work reports characterization following full-cycle rRNA approach (SSU sequence, specific in situ hybridization, ultrastructure) of a novel rickettsial bacterium, herewith proposed as 'Candidatus Megaira polyxenophila' gen....

Tubulins are still considered as typical proteins of Eukaryotes . However, more recently they have been found in the unusual bacteria Prosthecobacter ( btubAB ). In this study, genomic organization btub -genes and their environment were characterized by using newly developed Two-Step Gene Walking method. all investigated Prosthecobacters, organized a bacterial operon. Strikingly, -operons comprise third gene with similarities to kinesin light chain sequences. The environments always...

Abstract Members of the order Rickettsiales are often found in association with ciliated protists. An interesting case is bacterial endosymbiont “ Candidatus Megaira”, which phylogenetically closely related to pathogen Rickettsia . Megaira” was first described as an intracellular bacterium several ciliate species. Since then it has been diverse evolutionary distantly-related hosts, among them other unicellular eukaryotes, and also algae, metazoa, such cnidarians. We provide characterization...

Recently, the family Midichloriaceae has been described within bacterial order Rickettsiales. It includes a variety of endosymbionts detected in different metazoan host species belonging to Placozoa, Cnidaria, Arthropoda and Vertebrata. Representatives are also considered possible etiological agents certain animal diseases. have found protists like ciliates amoebae. The present work describes new endosymbiont, "Candidatus Fokinia solitaria", retrieved from three strains novel Paramecium...

Summary Bacterial strains affiliated to the phylogenetically shallow subcluster C (PnecC) of Polynucleobacter cluster, which is characterized by a minimal 16S rRNA gene sequence similarity approximately 98.5%, have been reported occur as obligate endosymbionts ciliates ( Euplotes spp.), well free‐living cells in pelagic zone freshwater habitats. We investigated if these two groups closely related bacteria represent fundamentally differing lifestyle, or they simply different stages...

We report the characterization of bacterial consortium associated to Euplotes focardii, a strictly psychrophilic marine ciliate that was maintained in laboratory cultures at 4 °C after its first isolation from Terra Nova Bay, Antarctica. By Illumina genome analyser, we obtained 11,179 contigs potential prokaryotic origin and classified them according NCBI's attributes table. The majority these sequences correspond either Bacteroidetes (16 %) or Proteobacteria (78 %). latter were dominated by...

Abstract Among the bacterial symbionts harbored by model organism Paramecium , many still lack a recent investigation that includes molecular characterization. The genus Lyticum consists of two species large-sized bacteria displaying numerous flagella, despite their inability to move inside hosts' cytoplasm. We present multidisciplinary redescription both species, using deposited type strains as well newly collected material. On basis 16S rRNA gene sequences, we assigned order Rickettsiales...

According to text book definition, parasites reduce the fitness of their hosts whereas mutualists provide benefits. But biotic and abiotic factors influence symbiotic interactions, thus under certain circumstances can benefits harm host. Here we addressed question which intrinsic shape a symbiosis are crucial for outcome interaction between obligate intranuclear bacterium Holospora caryophila (Alphaproteobacteria; Rickettsiales) its unicellular eukaryotic host Paramecium biaurelia...

Endosymbiosis is a widespread phenomenon and hosts of bacterial endosymbionts can be found all-over the eukaryotic tree life. Likely, this evolutionary success connected to altered phenotype arising from symbiotic association. The potential variety symbiont's contributions new characteristics or abilities host organisms are largely unstudied. Addressing aspect, we focused on an obligate endosymbiont that confers intraspecific killer its host. symbiosis between Paramecium tetraurelia...

Holospora and related bacteria are a group of obligate Paramecium symbionts. Characteristic features their infectivity, the presence two distinct morphotypes, usually strict specialization for single species as host nuclear compartment (either somatic or generative nucleus) reproduction. caryophila steps out line, naturally occurring in biaurelia caudatum. This study addresses phylogenetic relationship among H. other based on 16S rRNA gene sequence comparison analyzing type strain seven new...

Flagellates of the family Trypanosomatidae are obligate endoparasites, which can be found in various hosts. Several genera infect insects and occur as monoxenous parasites especially representatives Diptera Hemiptera. These trypanosomatid flagellates probably share worldwide distribution their hosts, often infested by large numbers endoparasites. Traditionally, taxonomy was based on morphology, host origin, life cycle. Here we report characterization a infection detected protozoan, ciliate...

Abstract Parasites with exclusive vertical transmission from host parent to offspring are an evolutionary puzzle. With parasite fitness entirely linked reproduction, any cost for infected hosts risks their selective elimination. Environmental conditions likely influence impact and thereby the success of purely strategies. We tested temperature‐dependent virulence Caedibacter taeniospiralis, a vertically transmitted bacterial symbiont protozoan Paramecium tetraurelia . compared growth cured...

ABSTRACT. Bacterial endosymbionts of protozoa were often described as new species by protozoologists mainly on the basis few morphological characters and partly host specificity. Many these have never been validated prokaryotic microbiologists whose taxonomic rules are quite different from those protozoologists, who use Zoological Code Nomenclature. “ Caedibacter macronucleorum ” Fokin Görtz 1993 , an endosymbiont Paramecium duboscqui belongs to this category. Here we provide molecular...

The ‘green’ ciliate Paramecium bursaria lives in mutualistic symbiosis with green algae belonging to the species Chlorella variabilis or Micractinium conductrix. We analysed diversity of algal endosymbionts and their P. hosts nine strains from geographically diverse origins. Therefore, phylogenies using different molecular markers were inferred. paramecia belong syngens bursaria. intracellular assigned Chl. variabilis, M. conductrix or, surprisingly, Choricystis parasitica. This usually...

Parasites frequently share their host populations with other parasites. However, little is known about how different parasites respond to competition diverse competitor species in the within‐host and between‐host environments. We explored repeatability of by simultaneously exposing microcosm ciliate Paramecium caudatum pairs from Holospora complex ( H. undulata , caryophila obtusa ). measured affected persistence prevalence each compared single infections, across three genotypes. Three weeks...

The role of bacterial endosymbionts harbored by heterotrophic Paramecium species is complex. Obligate intracellular bacteria supposedly always inflict costs as the host only possible provider resources. However, several experimental studies have shown that paramecia carrying can benefit from their infection. Here, we address question which occur in natural populations isolated a small lake over period 5 years and factors might explain observed shifts persistence symbionts occurrence. One...

Abstract Interest in host-symbiont interactions is continuously increasing, not only due to the growing recognition of importance microbiomes. Starting with detection and description novel symbionts, attention moves molecular consequences innovations symbioses. However, analysis requires genomic data which difficult obtain from obligate intracellular uncultivated bacteria. We report identification Caedibacter genome, an symbiont ciliate Paramecium . The infection does confer host ability...