Eva Tirjaková

Morphological and phylogenetical studies on a new soil hypotrich ciliate: Kahliella matisi spec. nov. (Hypotrichia, Kahliellidae).

The morphology, ontogenesis, encystment, and 18S rRNA gene sequence of a new soil hypotrich ciliate, Kahliella matisi, were studied. Main characteristics of K. matisi are: (1) two short and six longitudinal cirral rows right of the adoral zone of membranelles and four longitudinal rows left of it; (2) three dorsal kineties, of which kinety 1 extends along the left cell margin, kinety 2 runs in a slightly sigmoidal line, and kinety 3 is distinctly shortened posteriorly. Ontogenesis is similar to that in congeners, especially in the development of the marginal rows and long dorsal kineties, the preservation of some old cirral rows after division, and the direction of the neokinetal wave. However, there are some peculiarities: (1) reorganization of the proximal parental adoral membranelles; (2) splitting of opisthes anlage II into the cirral streak II and III; and (3) formation of the parental cirral row R3 from anlagen IV and V. During encystment, the body diminishes and becomes globular, the nuclear apparatus is reorganized, and the ciliature is resorbed. In our molecular phylogenies, the family Kahliellidae is polyphyletic and the position of K. matisi is rather poorly resolved, indicating a relationship with oxytrichids.

Analysis and evolution of water quality of the upper Váh River (northern Slovakia) by long-term changes in the community structure of ciliates (Protista: Ciliophora)

A long-term monitoring of the upper Váh River was carried out in order to evaluate evolution of water quality by means of ciliate taxocoenoses. One sampling station (Lisková) was located upstream of the pulp and paper mill in the town of Ružomberok, while two stations (Bystrá and Stankovany) were situated downstream of Ružomberok. Benthic samples were collected three times a year at each station during 2004–2011. This long-term study enabled us to assemble a comprehensive checklist of ciliates recorded in the upper Váh, and to characterize and compare the ciliate communities in the investigated watercourse. The saprobic index and valency analysis of the ciliate communities allowed us to quantify organic input and to evaluate changes in the saprobity of the upper Váh. The saprobic index ranged from 2.45 to 3.66 corresponding to the quality classes II–IV. Further, there was a prevalence of the α- and β-mesosaprobic levels, but during some periods the polysaprobic level increased along with the decrease of the β-mesosaprobic level. Beside the organic pollution, toxic contaminations were also noticed several times in the studied watercourse. This was documented by a significant drop in the species diversity and abundance of ciliates as well as by various morphological malformations and movement disorders of ciliates and other microorganisms. However, the negative effect of toxic and/or organic pollution wore off relatively quickly, indicating a good self-purification capability of the river.

Resting cysts of Parentocirrus hortualis Voß, 1997 (Ciliophora, Hypotrichia), with preliminary notes on encystation and various types of excystation.

Resting cysts of Parentocirrus hortualis were investigated, using live observation, SEM and TEM. Processes during encystation and excystation were observed in vivo under the light microscope. During encystation, the trophic body becomes globular, the ciliature is resorbed in an anterior direction, the macronuclear nodules fuse into an elongated mass, and finally a cyst wall develops. As typical for oxytrichids, the resting cysts of P. hortualis are of the kinetosome-resorbing type and their wall is made of four layers: ectocyst, mesocyst, endocyst, and metacyst. The beginning of excystation is indicated by the formation of an excystation vacuole that helps the regenerating specimen to break the cyst wall. The excysting specimen leaves the resting cyst in a thin membrane that is gradually resorbed in the outer environment. Also two other excystation modes were observed. During the rare mode, the excystation vacuole breaks the thin membrane instead of the cyst wall that ruptures under the pressure of the body of the regenerating specimen. During the reproduction mode, the regenerating specimen divides within the resting cyst, producing two to four tomites. This is the first report of division in resting cysts of oxytrichids, but reproduction in division cysts was already described in keronopsids.

First records of soil ciliates (Protozoa, Ciliophora) from classes Prostomea, Nassophorea, Spirotrichea, and Colpodea in Slovakia

In total, seven ciliate species were recorded in leaf-litter, moss and soil from a variety of sites in Slovakia for the first time: Chilophrya terricola Foissner, 1984; Holostichides typicus (Song et Wilbert, 1988) Eigner, 1994; Keronella gracilis Wiackowski, 1985; Notoxoma parabryophryides Foissner, 1993; Parafurgasonia sorex (Penard, 1922) Foissner et Adam, 1981; Paragonostomum multinucleatum Foissner, Agatha et Berger, 2002, and Territricha stramenticola Berger et Foissner, 1988. The paper deals with their distribution, ecology, and comparison with similar species. The shape and nuclear variants of Paragonostomum multinucleatum are presented and populations of P. multinucleatum and T. stramenticola are morphometrically characterized.

Recovery of ciliate communities from an oligotrophic mountain stream after a catastrophic wind damage

We studied the recovery of ciliate taxoceonoses in a mountain stream after a catastrophic windstorm that strongly affected mountainous regions of Slovakia in 2004. To this end, we analyzed changes in the community structure of ciliate assemblages from the Zubrovica stream in the Low Tatra Mts during the time frame between 2003 and 2008 by various statistical methods, including diversity and similarity indices, hierarchical clustering, multidimensional scaling, and PCA. The climax ciliate communities were characteristic for oligotrophic running waters, i.e., they were equitable (E(H) = 0.75-1.00) and harbored a comparatively low number of species (2-9) with typically low abundances (10-125 ind./ml). However, the community structure changed dramatically after the devastating windstorm. There was a significant increase of species number (10-30) and abundance (260-1480 ind./ml), concomitant with a decrease of the equitability (EH=0.43-0.83). These changed quantitative and qualitative community parameters wore off comparatively quickly, i.e., about six months after the catastrophic windstorm, the ciliate taxocoenoses had reached a community structure similar to that before the wind damage. The present observations and those from terrestrial habitats indicate that ciliate communities have a good capability to comparatively quickly reach a climax even after a strong disturbance.

Taxonomic Revision and Neotypification of Zosterodasys transversus (Kahl, 1928), with Description of a Mirror-Image Doublet (Ciliophora, Phyllopharyngea, Synhymeniida)

The present work describes the morphology and morphometry of a freshwater ciliate, Zosterodasys transversus, using live observation and protargol impregnation. The population from the River Ipeľ, Slovakia is designated as a neotype because (i) no type material is available from the species described by Kahl (1928); (ii) the neotype is consistent with Z. transversus as described by Kahl (1928); (iii) the neotype is from the same biogeographic region as Kahl’s (1928) populations; and (iv) there are several similar species (e.g., Z. agamalievi) whose identity is threatened by the species to be neotypified. The main features of Z. transversus are: (i) a body size of 120–240 × 50–115 μm in vivo; (ii) a broadly to narrowly obovate or elliptical body; (iii) a spherical to very narrowly ellipsoidal macronucleus with a single globular micronucleus nearby; (iv) several scattered contractile vacuoles; (v) an average of 82 ciliary rows, most of which are interrupted by a synhymenium incompletely encircling the body; and (vi) an average of 14 nematodesmal rods strengthening walls of the cyrtos. In the well-growing neotype population, a single cell of a mirror-image type was found. Most of the structures of this monster specimen are similar to those from ordinary cells, except for the double cytostome and cyrtos.

Observations on soil haptorid ciliates (Protozoa, Ciliophora) from Slovakia

The morphology and morphometry of five soil haptorid ciliates (Apospathidium terricola, Diplites telmatobius, Armatoenchelys geleii, Paraenchelys terricola, and Spathidium aciculare), collected from a variety of terrestrial habitats in Slovakia (Central Europe), were investigated using live observation and protargol impregnation. Emphasis was given on the ciliary pattern, the fine structure of dorsal brush, as well as the shape and size of the extrusomes. The Slovak specimens of A. geleii differ considerably from other populations investigated in detail by body size and micronuclei number. Furthermore, the most important difference concerns the number of dorsal brush rows (4 vs. 3). Therefore, it was decided to establish a new subspecies, namely Armatoenchelys geleii barborae ssp. n., for the Slovak population. Shape and nuclear variants of A. terricola and P. terricola are presented and morphometrically characterized. Novel details on the dorsal brush structure of A. terricola and D. telmatobius are reported. Pair formation and exconjugant nuclear reconstruction in P. terricola are described. Two species, namely A. terricola and S. aciculare, are first records for the Holoarctic biogeographic region.

Light microscopy observations on the encystation and excystation processes of the ciliate Phacodinium metchnikoffi (Ciliophora, Phacodiniidae), including additional information on its resting cysts structure

The scope of our study presents a light microscopy study on the encystation, excystation and morphology of the resting cysts of the spirotrich ciliate, Phacodinium metchnikoffi. During the encystation process, the trophic cell changes in shape, size and volume, the horseshoe-shaped macronuclear nodule transforms into a compact rounded mass, the ciliature is resorbed and the cyst wall is formed. A characteristic accumulation of dark substances in the cell cytoplasm was observed. The most significant feature is the surface. Ornamentation in the form of protuberances in regular rows is located on the entire surface of the cysts. We also focused on the excystation process for the first time and uncovered several specifics of P. metchnikoffi excystation. The excystation is characterised by the formation of the excystation vacuole. An escape apparatus is also present. The coexistence of the excystation vacuole and apparatus during the excystation process is an unusual type of escaping and has not yet been described. The results suggest that not only the resting cysts surface, but also the excystation and encystation processes are much more varied than literary data indicate.

Interaction of Ciliate Communities with Cyanobacterial Water Bloomin a Shallow, Hypertrophic Reservoir

The response of ciliate communities to cyanobacterial bloom was investigated in a shallow, hypertrophic reservoir in Slovakia, central Europe. Seasonal dynamics of ciliate communities corresponded negatively with course of water bloom formation. The highest numbers and abundances of ciliate species occurred during the spring season when cyanobacterial bloom was not fully developed, while there was an abrupt decrease in both numbers and abundances at the beginning of summer when water bloom culminated. Cyanobacterial blooming thus significantly lowered diversity and equitability of ciliate communities: many rare and sporadic species disappeared and few common taxa flourished and dominated. Nonetheless, these leading ciliates formed a functionally diverse assemblage whose members showed mostly positive contemporaneous and only rarely time-shifted interactions. There were fine filter feeders (Cinetochilum margaritaceum, Dexiotricha granulosa, Paramecium caudatum and Spirostomum teres) grazing heterotrophic bacteria and picocyanobacteria, omnivorous fine to coarse filter feeders (Frontonia leucas) as well as hunters (Coleps hirtus, Holophrya teres and Loxophyllum helus) looking for an individual prey. Also a comparatively rich, anaerobic coenosis comprising various bacterivorous armophoreans and plagiopyleans, developed at the bottom of the reservoir. Our study documents that ciliates form functionally diverse communities with potential to control cyanobacterial blooms in hypertrophic reservoirs.

Checklist and distribution of ciliates from the family Euplotidae Ehrenberg, 1838 (Protista: Ciliophora: Spirotrichea) in Slovakia, Central Europe

A checklist of ciliates from the family Euplotidae recorded in the territory of Slovakia, Central Europe was assembled. Altogether, 11 species belonging to three genera of the family Euplotidae have been reported there: Euplotes alatus, Euplotes charon, Euplotes moebiusi, Euplotoides aediculatus, Euplotoides eurystomus, Euplotoides patella, Euplotoides woodruffi, Euplotopsis affinis, Euplotopsis finki, Euplotopsis muscicola, and Euplotopsis novemcarinata. However, records of the marine species E. alatus and E. charon are doubtful and very likely represent misidentifications of E. moebiusi. Since the euryhaline species E. woodruffi was found for the first time in Slovakia, its morphology is described. Based on the literature data and our own observations, the present checklist is also accompanied with distribution data on the 11 aforementioned species. As concerns ecology, Slovak euplotids typically occurred in freshwater bodies having higher trophic levels. Only two species, E. finki and E. muscicola, were isolated from terrestrial habitats, especially, from mosses, leaf-litter, and decaying wood mass.