ABSTRACT “ Candidatus Midichloria mitochondrii” is an intramitochondrial bacterium of the order Rickettsiales associated with sheep tick Ixodes ricinus . Bacteria phylogenetically related to Ca (midichloria and like organisms [MALOs]) have been shown be a wide range hosts, from amoebae variety animals, including humans. Despite numerous studies focused on specific members MALO group, no comprehensive phylogenetic statistical analyses so far performed group as whole. Here, we present...

Endosymbioses between bacteria and eukaryotes are enormously important in ecology evolution, as such intensely studied. Despite this, the range of investigated hosts is narrow context whole eukaryotic tree life: most information pertains to animal hosts, while diversity found unicellular protists. A prominent case study ciliate Euplotes , which has repeatedly taken up bacterium Polynucleobacter from environment, triggering its transformation into obligate endosymbiont. This multiple origin...

Background The bacterial taxon Polynucleobacter necessarius subspecies asymbioticus represents a group of planktonic freshwater bacteria with cosmopolitan and ubiquitous distribution in standing habitats. These comprise <1% to 70% (on average about 20%) total bacterioplankton cells various ubiquity this was recently explained by intra-taxon ecological diversification, i.e. specialization lineages specific environmental conditions; however, details on adaptations are not known. Here we...

"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....

The order Rickettsiales (Alphaproteobacteria) is a well-known group containing obligate endocellular prokaryotes. encompasses three families (Rickettsiaceae, Anaplasmataceae, and Holosporaceae) fourth, family-level cluster, which includes only one candidate species, "Candidatus Midichloria mitochondrii," as well several unnamed bacterial symbionts. broad host range exhibited by the members of Midichloria" clade suggests their eventual relevance for better understanding evolution symbiosis...

Significance We have investigated multiple aspects of the Euplotes - Polynucleobacter system, which provides a unique opportunity for study an obligate symbiont with closely related free-living organism that itself possesses peculiarly reduced genome and metabolism. confirmed robustness generality patterns in evolution bacterial symbionts’ genome, adding at same time new elements hypotheses concerning reduction both symbiotic bacteria. argue this system will provide exceptionally useful...

Bacteria of the family Rickettsiaceae have always been largely studied not only for their importance in medical field, but also as model systems evolutionary biology. In fact, they share a recent common ancestor with mitochondria. The most species, belonging to genera Rickettsia and Orientia, are hosted by terrestrial arthropods include many human pathogens. Nevertheless, findings show that large part biodiversity actually resides outside group well-known pathogenic bacteria. Collecting data...

Ciliates comprise a diverse and ecologically important phylum of unicellular protists. One the most specious best-defined genera is Euplotes, which constitutes more than 70 morphospecies, many have never been molecularly tested. The increasing number described Euplotes taxa emphasizes importance for detailed characterizations new ones, requiring standardized morphological observations, sequencing molecular markers careful comparison with previous literature. Here we describe curdsi sp. nov.,...

The gut microbiota plays a basic role in maintaining the psychophysical health and well-being of horses. Understanding complex interactions among microbial communities relation to age, management, is topic growing interest. equine microbiota, given its complexity, subject variations caused by internal or external stressors that can lead metabolic problems pathologies, i.e., obesity laminitis. aim this study was characterize fecal 12 purebred Arabian horses compare two distinct management...

This paper reports the identification of bacterial endosymbionts that inhabit cytoplasm marine ciliated protozoon Euplotes magnicirratus. Ultrastructural and full-cycle rRNA approaches were used to reveal identity these bacteria. Based on analysis 16S gene sequences, evolutionary trees constructed; placed endosymbiont in genus Devosia α-Proteobacteria. The validity this finding was also shown by fluorescence situ hybridization with a Devosia-specific oligonucleotide probe. Differences at...

The Polynucleobacter-Euplotes association is an obligatory symbiotic system between a monophyletic group of ciliate species belonging to the genus Euplotes and bacteria Polynucleobacter necessarius (Betaproteobacteria). Both organisms are unable survive independently. Several studies revealed existence free-living populations which phylogenetically closely related endosymbiotic ones, but never share associations with in natural environment. Hence, following most parsimonious explanation on...

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...

Abstract. We have found a Polynucleobacter bacterium in the cytoplasm of Euplotes harpa , species living brackish‐water habitat, with cirral pattern not corresponding to that freshwater known harbor this type bacteria. The symbiont has been three strains species, obtained by clonal cultures from ciliates collected different geographic regions. 16S rRNA gene sequence identifies it as member β‐proteobacterial genus . This shares high similarity value (98.4–98.5%) P. necessarius genus, and is...

Ammonium and nitrite oxidizing biomasses (AOB NOB) were investigated in parallel pilot plants: a membrane bioreactor (MBR) conventional activated sludge process (CASP) fed with domestic wastewater. The kinetics of AOB NOB monitored through titrimetric tests. maximum specific growth rate the (micro(max,AOB)) was affected by solids' retention time (SRT) maintained during start up: varying up SRT from 20 d to 8 d, micro(max,AOB) CASP varied 0.45 d(-1) +/- 0.04 0.72 0.2 respectively; mean value...

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsSpecials 70:233-243 (2013) - DOI: https://doi.org/10.3354/ame01657 A new obligate bacterial symbiont colonizing ciliate Euplotes in brackish and freshwater: 'Candidatus Protistobacter heckmanni' Claudia Vannini*, Filippo Ferrantini, Franco Verni, Giulio Petroni Biology Department, Protistology-Zoology Unit, University of Pisa,...