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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
72 • "PROTIST—2016
Cryosol profiles by different processes of cryogenic mass-exchange. According to our results about half of protists communities in Cryosols have adaptive and protective mechanisms enabling long-term cryptobiosis in the inhospitable conditions of the arctic soils and permafrost. Fragments of the uppermost soil horizons that were cryoturbated, buried by solifluction and accumulated in the upper layer ofpermafrost appear to be the ecologycal niche in profiles of Turbic Cryosols that can significantly sustain viability of protists.
GENOME ANNOTATION OF ACRASIS KONA Sheikh Sanea, Fu Chengjie, Baldauf Sandra Department of Organismal Biology, Uppsala University, Sweden [email protected]
Acrasids are single-celled amoebae that can undergo aggregative multicellularity in response to adverse environmental conditions, similar to the well-studied dictyostelid social amoebas. However, acrasids are unrelated to dictyostelids (supergroup Amoebozoa), being instead the only multicellular lineage in the eukaryotic supergroup Excavata. This makes Acrasis an interesting model system to study parallel evolution of social behavior in microbes as well as to explore the diversity of eukaryotes in general. We have sequenced the genome and transcriptome of Acrasis kona and are currently preparing transcriptomes from the four main stages of its life cycle. In initial work, we assembled the complete A. kona mitochondrial genome (mtDNA) and find that it is missing 14 protein genes present in the mtDNA of its closest sequenced relative, Naegleria gruberii. We further identified 11 of these protein genes in A. kona nuclear DNA and find that they carry mitochondrial important signals (transit peptides, Fu et al. 2014). We are now using RNAseq data and the N. gruberii genome in an annotation pipeline to create a fully annotated A. kona nuclear assembly. The results will be used to investigate parallel evolution of simple multicellularity, early steps in the evolution of eukaryotes and to aid in resolution of the eukaryote tree of life by breaking up some of the longer deep branches.
CHEMOTAXIS RESPONSE OF PHYTOPLAN-
KTON TO CILIATES
Shen Z.12, Vidyarathna N.K.1, Liu H.B.1
1 - Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong
2 - Institute of Hydrobiology, Jinan University, Guangzhou 510631, China
Marine environment at the micro scale level is
heterogeneous in terms of nutrient distribution and many microbial species can actively exploit these nutrient patches. Exudates of microbes act as nutrient hotspots and also provide chemical cues to their prey or predators. In the present study we examined the chemotactic response of starved and/ or non-starved Dunaliella salina to the exudates of ciliate grazers (Euplotes vannus, Euplotes sp., and Diophrys oligothrix) by using two approaches; 1. Co-culturing oftwo species under different illumination conditions to evaluate the growth, ingestion and behavioural response of the phytoplankton and/ or ciliates and 2. Using microfluidics and image analyses to evaluate the response of D. salina to the exudates of ciliates and related nutrient media. D. salina showed different active swimming and an 'attack-like' behaviour towards ciliates under different illumination conditions, despite the high ciliate grazing rates on them. When exposed to the patches of ciliate exudates, f/2 growth medium, yeast extraction and ammonium solution, both starved and non-starved D. salina showed chemotactic accumulation on/around the exudate and nutrient patches. In both cases positive chemotaxis indices were found towards ciliate exudates suggesting that D. salina could actively uptake nutrients released by its ciliate grazers. This specific behavioural response however, could be costly to D. salina. We suggest that this behaviour could also serve as a defence mechanism thereby increasing the benefits for D. salina.
PELAGIC PROTISTS FEEDING ON PICO-CYANOBACTERIA AND THEIR CHLOROPHYLL CATABOLISMS
Shihongi A.1, Kinoshita Y.2, Ishikawa A.3, Tamiaki H.2, Kashiyama Y.1,2
1 - Fukui University of Technology
2 - Ritsumeikan University
3 - Mie University [email protected]
Pico-phytoplanktons dominate the primary production in pelagic oligotrophic oceans. Because these settings cover roughly half areas of the Earth surface, thus relatively dilute inhabitances of pico-phytoplanktons actually represent a considerable proportion of the photosynthetic primary production on the Earth. Nonetheless, ecological/bioenergetic networks extended from these microbial phototrophs have been poorly understood due to insufficient knowledge on the prey-predator relationship, where the minute cells should evade grazing by filter-feeding zooplanktons. We have thus investigated on pelagic protists that potentially prey on picophytoplanktons based on
