TY - JOUR

T1 - ‘‘Candidatus Trichorickettsia mobilis’’, a Rickettsiales bacterium, can be transiently transferred from the unicellular eukaryote Paramecium to the planarian Dugesia japonica.

AU - Modeo, Letizia

AU - Salvetti, Alessandra

AU - Rossi, Leonardo

AU - Castelli, Michele

AU - Szokoli, Franzisca

AU - Krenek, Sascha

AU - Serra, Valentina

AU - Сабанеева, Елена Валентиновна

AU - Di Giuzeppe, Graziano

AU - Фокин, Сергей Иванович

AU - Verni, Franco

AU - Petroni, Giulio

N1 - Funding Information: This work received financial support from the following projects: Progetti di Ricerca di Ateneo (PRA), project PRA_ 2016_58, University of Pisa to Giulio Petroni; Russian Foundation for Basic Research (RFBR), grant No 18-04-00562-a to Elena Sabaneyeva. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Funding Information: The following grant information was disclosed by the authors: Progetti di Ricerca di Ateneo (PRA), project PRA_ 2016_58, University of Pisa. Russian Foundation for Basic Research (RFBR): 18-04-00562-a.

PY - 2020/4/23

Y1 - 2020/4/23

N2 - Most of the microorganisms responsible for vector-borne diseases (VBD) have hematophagous arthropods as vector/reservoir. Recently, many new species of microorganisms phylogenetically related to agents of VBD were found in a variety of aquatic eukaryotic hosts; in particular, numerous new bacterial species related to the genus Rickettsia (Alphaproteobacteria, Rickettsiales) were discovered in protist ciliates and other unicellular eukaryotes. Although their pathogenicity for humans and terrestrial animals is not known, several indirect indications exist that these bacteria might act as etiological agents of possible VBD of aquatic organisms, with protists as vectors. In the present study, a novel strain of the Rickettsia-Like Organism (RLO) endosymbiont ''Candidatus (Ca.) Trichorickettsia mobilis'' was identified in the macronucleus of the ciliate Paramecium multimicronucleatum. We performed transfection experiments of this RLO to planarians (Dugesia japonica) per os. Indeed, the latter is a widely used model system for studying bacteria pathogenic to humans and other Metazoa. In transfection experiments, homogenized paramecia were added to food of antibiotic-treated planarians. Treated and non-treated (i.e. control) planarians were investigated at day 1, 3, and 7 after feeding for endosymbiont presence by means of PCR and ultrastructural analyses. Obtained results were fully concordant and suggest that this RLO endosymbiont can be transiently transferred from ciliates to metazoans, being detected up to day 7 in treated planarians' enterocytes. Our findings might offer insights into the potential role of ciliates or other protists as putative vectors for diseases caused by Rickettsiales or other RLOs and occurring in fish farms or in the wild.

AB - Most of the microorganisms responsible for vector-borne diseases (VBD) have hematophagous arthropods as vector/reservoir. Recently, many new species of microorganisms phylogenetically related to agents of VBD were found in a variety of aquatic eukaryotic hosts; in particular, numerous new bacterial species related to the genus Rickettsia (Alphaproteobacteria, Rickettsiales) were discovered in protist ciliates and other unicellular eukaryotes. Although their pathogenicity for humans and terrestrial animals is not known, several indirect indications exist that these bacteria might act as etiological agents of possible VBD of aquatic organisms, with protists as vectors. In the present study, a novel strain of the Rickettsia-Like Organism (RLO) endosymbiont ''Candidatus (Ca.) Trichorickettsia mobilis'' was identified in the macronucleus of the ciliate Paramecium multimicronucleatum. We performed transfection experiments of this RLO to planarians (Dugesia japonica) per os. Indeed, the latter is a widely used model system for studying bacteria pathogenic to humans and other Metazoa. In transfection experiments, homogenized paramecia were added to food of antibiotic-treated planarians. Treated and non-treated (i.e. control) planarians were investigated at day 1, 3, and 7 after feeding for endosymbiont presence by means of PCR and ultrastructural analyses. Obtained results were fully concordant and suggest that this RLO endosymbiont can be transiently transferred from ciliates to metazoans, being detected up to day 7 in treated planarians' enterocytes. Our findings might offer insights into the potential role of ciliates or other protists as putative vectors for diseases caused by Rickettsiales or other RLOs and occurring in fish farms or in the wild.

KW - Candidatus Trichorickettsia

KW - FISH

KW - Molecular characterization

KW - Paramecium multimicronucleatum

KW - Planarians

KW - Rickettsia-like organism (RLO) endosymbiont

KW - Rickettsiaceae

KW - Transfection experiments

KW - Ultrastructure

KW - Vector-borne diseases

KW - ENDOSYMBIONTS

KW - IN-SITU DETECTION

KW - "Candidatus Trichorickettsia"

KW - HOST

KW - IDENTIFICATION

KW - EUPLOTES CILIOPHORA

KW - DISEASE

KW - NECROTIZING HEPATOPANCREATITIS

KW - DIVERSITY

KW - SP-NOV

KW - STAPHYLOCOCCUS-AUREUS

UR - http://www.scopus.com/inward/record.url?scp=85085942015&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/d8a870cc-5409-3beb-a3dc-bc1a1982b991/

U2 - 10.7717/peerj.8977

DO - 10.7717/peerj.8977

M3 - Article

C2 - 32351785

VL - 2020

JO - PeerJ

JF - PeerJ

SN - 2167-8359

IS - 4

M1 - e8977

ER -