Научная статья на тему 'New data on the ultrastructure of the genus Paradermamoeba: unusual feeding mode and presence of cytoplasmic MTOCs'

New data on the ultrastructure of the genus Paradermamoeba: unusual feeding mode and presence of cytoplasmic MTOCs Текст научной статьи по специальности «Биологические науки»

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Protistology
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Текст научной работы на тему «New data on the ultrastructure of the genus Paradermamoeba: unusual feeding mode and presence of cytoplasmic MTOCs»

Protistology ■ 31

110007

3 - Natural History Museum, London, SW7 5BD, UK komalkamra@gmail.com

River Yamuna maintains a reasonably good quality from its origin in the Himalayas to its entry into the National Capital Region (NCR) of Delhi, India. 18 sewage drains carrying industrial and domestic wastes flow into the river in the 22 km stretch (1.6% of total length) as it flows through the NCR. 80% of the pollution in the river's total length of 1375 km occurs as it passes through the NCR, severely compromising its water quality. As free-living ciliated protist species differ widely in tolerance to pollutants, the present study was conducted to catalogue ciliate communities (with appropriate morphological, morphometric and morphogenetic descriptions) at two selected locations along the river, namely the point where the river enters the NCR (S1) and 500 m downstream of the site where the largest sewage drain empties into the river (S2). Physico-chemical parameters including heavy metal concentrations were analyzed in order to assess the water quality at these two locations. Compared to S1: the Biochemical Oxygen Demand and phosphate concentrations increased 5X at S2; total hardness, total dissolved solids, conductivity, turbidity and nitrates doubled at S2; total coliforms and faecal coliform increased 50X at S2; lead concentration increased 2X times and arsenic 3X at S2. There was a significant fall in the species richness and abundance of ciliated protists at S2. Ofthe hypotrichous ciliates, there was a significant loss of members of the family Oxytrichidae, whereas euplotid populations were maintained. The changes in ciliate community will be discussed with respect to water quality.

NEW DATA ON THE ULTRASTRUCTURE OF THE GENUS PARADERMAMOEBA: UNUSUAL FEEDING MODE AND PRESENCE OF CYTOPLASMIC MTOCS Kamyshatskaya O.G., Smirnov A.V. Departmentoflnvertebrate Zoology, Faculty of Biology, St. Petersburg State University, St. Petersburg, Russia oksana.kamyshatskaya@gmail.com Naked amoebae engulf food objects via phagocytosis, and during this process the portion of cell membrane covered with the glycocalyx appears inside newly formed food vacuoles. Further cell has to restore membrane and reconstruct respective portion of the glycocalyx. It may be an energetically costly process for species possessing thick and highly differentiated glycocalyx. Genus Paradermamoeba (phylum Amoebozoa, class Discosea) includes two species — P. levis and P. valamo. Both possess highly differentiated cell coat composed of tightly

packed helical glycostyles, ca. 220 nm in thickness in P. levis and ca. 520 nm in P. valamo. Our study reveals that during formation of the food vacuole P. valamo resorbs cell coat at the area of contact with food object, thus avoiding digestion of glycocalyx elements. The similar feeding mode is known in other thick-coated amoebae, like Pellita and Dermamoeba. This observation confirms our earlier hypothesis, stating that thick-coated amoebae have to adopt special ways to avoid energetically costly digestion and further reconstruction of glycocalyx elements. We provide the first description of the cytoplasmic microtubule-organising centres (MTOCs) associated with dictyosomes ofthe Golgi complex in genus Paradermamoeba. This finding confirms the hypothesis that presence of cytoplasmic MTOCs is a synapomorphy of the phylogenetic lineages forming the subclass Longamoebia. Detailed study of the ultrastructure of P. levis reveals that so-called "supernumerary nucleus" of P. levis noted in the initial description is not an individual structure but an outgrowth of the cell nucleus containing its own nucleolus. Supported with RSF grant 14-14-00474.

ISOLATION OF FREE-LIVING AMOEBAE FROM SOUTHERN HAN-LIVER IN KOREA Kang H.K.12, Seong G.S.12, Sohn H.J.1-2, Jung S.Y.3, Lee S.E.4, Park M.Y.4, Shin H.J.12

1 - DepartmentofMicrobiology, Ajou University School of Medicine

2 - Department of Biomedical Science, Graduate School of Ajou University, Suwon 443-721, Republic of Korea

3 - Department of Biomedical Laboratory Science, Molecular Diagnostics Research Institute, School of Health and Medicine, Namseoul University, Cheonan 31020, Republic of Korea

4 - Division of Malaria and Parasitic Disease, Korea National Institute ofHealth, Osong363-951, Republic of Korea

hkkang@ajou.ac.kr

Pathogenic Naegleria fowleri and Acanthamoeba spp., free-living amoebae exist in the natural environment, are causing agents of an acute and lethal primary amoebic meningoencephalitis (PAM) and amoebic keratitis (AK) in humans, respectively. To ascertain the existence of free-living amoebae in Korea, in late August 2015, water samples of eight sites were collected in Korean hydrosphere where water skiing and recreation have been actively performed, and then the non-nutrient agar culture and PCR-based detection technique were carried out. The surface waters were collected and filtered, and then final samples were cultured

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