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22
Protistology ■ 71
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
