CC BY
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70 • "PROTIST—2016
Italy
2 - Department of Invertebrate Zoology, St. Petersburg State University, St. Petersburg, Russia
3 - Department of Zoology, Andhra University, Visakhapatnam, India
4 - Department of Biotechnology, Andhra University, Visakhapatnam, India [email protected]
Ciliates are known since a long time to be potential hosts for bacteria. Some of the most investigated species belong to the so-called Holospora-like bacteria (HLB) group, which includes all known Holospora species and " Candidatus Gortzia" genus. HLB are obligate endosymbionts, inhabiting the macronucleus or the micronucleus of certain species of Paramecium and, less frequently, Frontonia. They are Gram-negative, non-motile Alphapro-teobacteria with a distinctive life cycle involving two different morphotypes: the smaller and almost roundish reproductive (RF) form, and the much more elongated, rod-like infectious form (IF). In the present work we describe a novel species belonging to "Ca. Gortzia" genus, detected in P. multimicronucleatum, a ciliate in which HLB have never been reported before. This novel endo-symbiont shows unusual features respect its relatives, such as deep variations in IF morphology and capability to infect occasionally host cytoplasm. It presents small, roundish RF (2.5-3.3 ^m) and rod-shaped IF. Two morphotypes of IF were detected in different periods: a shorter IF at the beginning (6.9-10.7 ^m), and a longer one (8.2—14.7 ^m) with irregular distribution of periplasm after one year of cultivation. The latest were found together with a high number of transient forms (TF), which appeared long (6.7—15.5 ^m), rod-shaped and not yet differentiated in IF at ultrastructural level. All forms show a constant diameter of 0.7-0.8 ^m. No production of "connecting piece" during host cell division was observed. We propose for this novel HLB from India the name of " Candidatus Gortzia shahrazadis".
INTERACTION OF DIFFERENT SYMBIOTIC BACTERIA IN THE CILIATE PARAMECIUM Shaidullina A.1, Lanzoni O.2, Lebedeva N.3, Potekhin A.1
1 - Faculty of Biology, St Petersburg State University, Saint Petersburg, Russia
2 - Department of Biology, University of Pisa, Pisa, Italy
3 - Centre of Core Facilities "Culture Collections of Microorganisms", St Petersburg State University, Saint Petersburg, Russia [email protected]
Multiple bacterial symbioses are rather common phenomenon in ciliates. Some intracellular bacteria, like "Candidatus Megaira polyxenophila", apparently do not produce any effect on the host, and their mode of interaction with ciliate is unknown; some other, like Holospora, are highly infectious bacteria actively exploiting the host resources. However, little is known about interactions among endosymbiotic bacteria inhabiting the same host cell. The simultaneous infection of a ciliate with several bacteria has been observed but not studied in detail. Finally, the ability of a bacterium to enter and associate with the host cell already occupied by another symbiont remains unclear; indeed the possible competition for the same cell compartment between the "native" bacterium and an "invader" has never been investigated. We analyzed how the host cell reacts to multiple infections, and how different symbiotic bacteria interact inside the host. For this purpose, four strains of Paramecium caudatum harboring " Candidatus Megaira polyxenophila" in macronucleus were experimentally infected with representatives of several Holospora species. During our observations " Candidatus Megaira polyxenophila" prevented development of macronuclear Holospora species, thus showing the tendency to be the only occupier of the host macronucleus. On the contrary, "Candidatus Megaira polyxenophila" allowed the entrance of Holospora undulata in the host micronucleus, even in presence of other cytoplasmic endosymbionts. Results on reciprocal infections (paramecia harboring Holospora infected with " Candidatus Megaira polyxenophila") also suggested that symbionts protect their cell compartment from invasions by other bacteria in order to ensure their persistence and spreading in the environment. Supported by RFBR 16-04-01195.
CANINE BABESIOSIS IN MOSCOW REGION OF RUSSIA
Shaitanov V.M., Yastreb V.B.
K.I. Skriabin All-Russian Institute for Fundamental
and Applied Parasitology of Animals and Plants
The blood smears of dogs were examined in Moscow region under light microscope in 2011-2014. If Babesia merozoites were detected the samples were examined with IFA-tests SNAP 4Dx against for Ehrlichia canis, Anaplasma phagocytophilum, Borrelia burgdorferi s.l., Dirofilaria immitis. The microfilaria were visualized in samples after concentration. Differential staining of acid phosphatases was used to distinguish Dirofilaria microfilaria. Anamnesis of infected dogs was analyzed. The ticks were removed
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from dogs inside veterinary clinic or collected from vegetation in different ecosystems biotopes of Moscow region. During the survey 1045 ticks were collected (Dermacentor reticulatus, Ixodes ricinus, I. persulcatus). In the natural habitats ofMoscow region 480 ticks were collected (I. ricinus, I. persulcatus, D. reticulatus). It is presumed that only D. reticulatus is a natural agent ofbabesiosis transmission in Moscow region. In total 283 cases of babesiosis of dogs were reported, with 8,0% of cases reported for dogs never leaving city limits. Remaining 92 % of dogs were transported from time to time to country side. In the majority of dogs the babesiosis is developing without severe consequences, and only in 2,5% of cases the acute renal failure was diagnosed. In 1,7% of dogs autoimmune hemolytic anemia was observed. About 0,7% ofstudied dogs were seropositive for D. immitis all other pathogens were absent in these animals. In 1,7% of cases the microfilaria of D. repens were detected and in 0,7% of cases the microfilaria of D. immitis were found.
N-ACETYL ORNITHINE DEACETYLASE IS A MOONLIGHTING PROTEIN AND IS INVOLVED IN THE ADAPTATION OF ENTAMOEBA HISTOLYTICA TO NITROSATIVE STRESS
Shahi P.1, Vanunu S.1, Avrahami A.1, Trebicz-Geffen M.1, Nagaraja S.1, Hertz R.1, Alterzon-Baumel S.1, Reiter I.1, Methling K.2, Lalk M.2, Mazumder M.3, Samudrala G.3
1 - Faculty of Medicine, Technion
2 - Institute of Biochemistry, University of Greifswald
3 - Jawaharlal Nehru University School of Life Sciences
Entamoeba histolytica is a causative protozoan parasite of amebiasis, a disease which is characterized by acute inflammation of the colon. Adaptation of the parasite to toxic levels of nitric oxide (NO) that are produced by phagocytes may be essential for the establishment of chronic amebiasis and the parasite's survival in its host. In order to obtain insight into the mechanism of E. histolytica's adaptation to NO, E. histolytica trophozoites were progressively adapted to increasing amounts of the NO donor drug, S-nitrosoglutathione (GSNO) up to a concentration of 110 ^M. These NO-adapted trophozoites (NAT) were more resistant to an acute exposure of 350 ^M GSNO) and activated macrophages and were better at invading porcine colon explants than wild-type trophozoites. The transcriptome of NATs was investigated by RNA sequencing (RNA-seq) and the results of the analysis revealed the existence of a weak overlap
with the transcriptome of acute nitrosative-stres-sed trophozoites (TEANS). N-acetyl ornithine deacetylase (NAOD) was among the 208 genes that were up-regulated in NAT. NAOD catalyzes the deacylation of N-acetyl-L-ornithine to yield ornithine and acetate. Overexpression of NAOD resulted in significant overproduction of putrescine and in a better adaptation to NS. Surprisingly, overexpression of a catalytically inactive NAOD (mNAOD) resulted in a better adaptation to NS but did not result in putrescine overexpression. These results suggest that NAOD has moonlighting activity. The binding of NAOD or mNAOD to glyceraldehyde 3-phosphate dehydrogenase (GAP DH) prevents the formation of putatively toxic high molecular weight GAPDH species and the absence of these species may underlie the parasite's ability to survive NS.
DISTRIBUTION AND CRYOCONSERVA-TION OF PROTISTS IN THE ARCTIC SOILS Shatilovich A.V.1, Mylnikov A.P.2, Bykova S.V.3, Lupachev A.V.1, Gubin S.V.1
1 - Institute of Physico-chemical and Biological Problems in Soil Science, RAS, Pushchino, Russia
2 - Institute for Biology ofInland Waters, RAS, Borok, Russia
3 - Institute ofEcology of the Volga River Basin, RAS, Togliatti, Russia [email protected]
Previous investigations have shown that resting cysts of soil protists can survive in permafrost for thousands of years at subzero temperatures. However, our knowledge about mechanisms of long-term cryobiosis remains incomplete. One of the uncertainties is the mechanism of cysts transition into the frozen deposits. The main goal of the study was to gauge the protists species abundance and diversity in the profiles of Cryosols - typical arctic soil, that are subjected to the different processes of cryogenic mass-exchange redistributed the fragments of the uppermost soil horizons with microorganisms inhabiting this material. Taxono-mic analysis of ciliates and heterotrophic flagellates isolated from 21 soil samples revealed 40 species and forms of heterotrophic flagellates from 9 taxonomical groups and 32 species of ciliates from 7 taxonomical groups. Protists vertical distribution in soil profiles allows to select two groups of species: 1) species occur only in the modern uppermost soil horizons and 2) part of the protists' community (53% and 55% of ciliates and flagellates species respectively) that occurs in material of organic and organo-mineral soil horizons both a modern and buried into the middle and lowermost parts of
