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Protistology ■ 49
measures 30^28 ^m and is attached to the bottom of the lorica by a contractile peduncle. The somatic ciliary pattern is of the most complex type, i.e., it comprises a ventral, dorsal, and posterior kinety as well as a right, left, and lateral ciliary field. The ventral kinety has associated an extraordinary ciliary tuft of cell length that extends outside the lorica posteriorly, resembling the golden hair let down from the tower by Rapunzel; T. subacuta is unique in this respect. The right and left ciliary fields are composed of about 11 ciliary rows each, the lateral field consists of invariably 15 rows. While the majority of tintinnids have only two macronucleus nodules, T. subacuta has 4—34, on average 14 nodules. Financially supported by FWF Project P28790.
PROTISTAN VERSUS CYANOBACTERIAL PICOPHYTOPLANKTON PRODUCTION AND GRAZING MORTALITY IN SEVASTOPOL BAY AND ADJACENT WATERS (THE BLACK SEA)
Mukhanov V.S., Rylkova O.A., Sakhon E.G. A.O. Kovalevsky Institute of Marine Biological Research, Russian Academy of Sciences, Nakhimov av. 2, Sevastopol, 299011, Russia [email protected]
Seasonal dynamics of abundance, specific growth rate, daily production and grazing mortality of the major picophytoplankton components, eukaryotic protists and prokaryotic cyanobacteria, were studied at three stations in Sevastopol bay and adjacent waters (the Black Sea) in 2014 by flow cytometry and dilution method. In the shallow coastal waters, protistan picophytoplankton (PP) dominated (64 ± 23 (SD) %, n=26) the community in terms of abundance (annual average of 16.3 ± 12.4 * 103 cells ml-1), with the latter increasing along the nutrient and pollution gradient from the coastal waters outside the bay (7.3 ± 5.4 * 103 cells ml-1) to the eastern corner ofthe bay (28.7 ± 11.4 * 103 cells ml-1). PP demonstrated significantly lower specific growth rates (0.20 ± 0.19 d-1) and significantly higher daily grazing mortality (4.0 ± 5.8 ^g C l-1 d-1) than cyanobacterial picophytoplankton (0.70 ± 0.46 d-1 and 1.1 ± 1.1 ^g C l-1 d-1, respectively) while the protistan and cyanobacterial daily productions did not differ significantly (paired t-test, p>0.05, n=26). Matter flows through both the community components were comparable to or even exceeded their biomass stocks that indicated high biomass turnover rates. Thus, the protistan component has been shown to play a major role in the community functioning in the Black Sea coastal waters.
THE SPECIALIZATION OF THE PROTO-MITOCHONDRION AS A RESPIRATORY ORGANELLE
Muñoz-Gómez S.A., Roger A.J., Slamovits C.H. Centre for Comparative Genomics and Evolutionary Bioinformatics, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada. [email protected]
The ancestor of mitochondria was an alpha-proteobacterium whose exact phylogenetic and phenotypic nature remains obscure. Therefore, the proximate selective force that drove the initial endosymbiosis is unknown, even though the ultimate selective advantage was undoubtedly greater efficiency in energy production through aerobic respiration. The specialization of the proto-mitochondrion as the respiratory organelle of eukaryotes required the host to exert increased control over the biogenesis of the newly evolving organelle. Among the several adaptations that transformed the ancestral endosymbiont into a respiratory organelle, two evolutionary innovations were of major importance. The first major innovation was the evolution of mitochondrial cristae to make respiratory sub-compartments. Cristae likely evolved from precursor structures in alpha-proteobacteria. Later molecular innovations further modified cristae to improve their respiratory function. This required the expansion of MICOS (Mitochondrial contact site and Cristae Organizing System) and the evolution of the capability of the ATP synthase complex to form multimers. The second major innovation was the evolution of the ability ofthe host to control the overall morphology, positioning and distribution of mitochondria within the cell. These adaptations optimized bioenergetic output in response to host needs. This was made possible by the origin of mitochondrial fusion, as well as the establishment of interactions between mitochondria and diverse endomembranes and the cytoskeleton. I discuss a detailed evolutionary scenario for the evolution of these two major adaptations in the context of the co-evolutionary integration of mitochondria and their host.
THE ULTRASTRUCTURE OF AMOEBOID
FLAGELLATES AMASTIGOMONAS (CERCO-
ZOA, RHISARIA)
Mylnikov A.A., Mylnikov A.P.
Papanin Institute for Biology of Inland Waters,
Russian Academy of Sciences, Borok, Russia
The cytoskeleton of three amoeboid flagellates Amastigomonas spp. dwelling in freshwater (one
