Fuscheriid haptorids are characterized by meridionally extending ciliary rows clearly separated from the dikinetidal circumoral kinety; a two- or three-rowed dorsal brush; and oral basket rods (nematodesmata) originating from both, the circumoral dikinetids and from some oralized monokinetids in the anterior portion of the ciliary rows. Using standard morphological methods, we describe four new fuscheriid taxa, each discovered in a specific biogeographic region. Fuscheriides tibetensis nov. gen., nov. spec. has rod-shaped extrusomes and two dorsal brush rows. It is a small (~ 80 × 10 μm), slender ciliate with only seven ciliary rows, and was discovered in grassland soil of southern Tibet, about 4600 m above sea-level. Aciculoplites ethiopiensis nov. gen., nov. spec. has acicular extrusomes and two dorsal brush rows. It is a middle-sized (~ 100 × 30 μm), oblong ciliate with about 22 ciliary rows, and was discovered in floodplain soil from a lake in Ethiopia. Fuscheria uluruensis nov. spec., which we discovered in mud and aeolic soil from pools on top of the Ayers Rock in the red centre of Australia, is unique in having the macronucleus split into about 12 oblong nodules. The nodules originate post-divisionally via the branching macronucleus strand, as in multinucleate spathidiids. Fuscheria nodosa salisburgensis nov. sspec., which was discovered in mud and soil of a meadow pool in Salzburg (Austria), has a long, tortuous macronucleus and about 45 ciliary rows. The resting cyst has an escape apparatus absent from the cyst of F. uluruensis, indicating that Fuscheria is non-monophyletic.

This is the first report on the diversity of small free-living amoebae (FLA) in carbonate precipitating habitats in karst caves. Of 11 samples from nine different habitats in four Slovenian karst caves ten samples were positive for FLA, four strains were successfully isolated and transferred to clonal monoxenic cultures, including Acanthamoeba castellanii genotype T4, Echinamoeba silvestris, Hartmannella vermiformis, and a new vahlkampfiid amoeba Allovahlkampfia spelaea gen. nov., sp. nov. The latter was isolated from a stromatolitic stalagmite, a typical biogenic speleothem. Echinamoeba silvestris was identified from an aerophytic algal community and Acanthamoeba and Hartmannella were isolated from a cave pool with floating calcite rafts. The grazing of FLA on bacteria may help in creating conditions that enhance carbonate precipitation.

Spore variability of Ceratomyxa appendiculata Thélohan, 1892, found in the gallbladder of black angler-fish, Lophius budegassa from NE Spain were studied by light microscopy and, for the first time, by scanning electron microscopy. More than 18,000 spores of C. appendiculata were examined, classified and quantified. Of this, 98.31% were bivalvular normal spores, the rest were abnormal spores (1.63% were trivalvular spores and 0.06% were tetravalvular spores). The monthly evolution of these spores was followed for ten months. Differences among the proportions of trivalvular spores in different months were significant. Percentage of trivalvular spores ranged from 9.90% (May) to 0.00% (December). The highest percentage of tetravalvular spores was reached in november (0.39%). Some polysporous trophozoites can produce simultaneously normal and abnormal spores.

Among a population of Thecamoeba quadrilineata (Thecamoebidae) isolated from moss samples some trophozoites harboured intracellular aggregates of round-oval parasites which turned out to be spores with a real nucleus. These organisms were supposed to be fungal endoparasites beginning their development within the nucleus of the host invaded by young parasitic stages after the host amoeba had engulfed free spores from the environment. The complete developmental cycle was studied by electron microscopy, showing the intranuclear growth of freshly invaded young stages into large spore forming parasites differentiating into a great number of spores – all within the border of the host’s nuclear membrane. These spores were not released into the environment until the death and decay of the host amoeba, where they could be ingested as infective stages by hitherto not infected thecamoebae. Host range studies with various free-living amoebae (FLA) showed that T. striata and T. terricola were as permissive to infection as the original host T. quadrilineata. Sappinia was only susceptible to a certain extent and therefore not considered as possible natural host. Remarkably, this observation shows that both nuclei of the bi-nucleate amoeba became simultaneously infected. The present morphological description corresponds to early observations with fungal intranuclear parasites called Nucleophaga Dangeard, 1887. However, genetic and phylogenetic studies have to corroborate the supposed fungal nature.

The effects of linoleic acid supplementation on protozoa counts, fermentation parameters and fatty-acid composition of Entodinium caudatum and Diploplastron affine were examined in in vitro cultures. Entodinium caudatum (EC) and Diploplastron affine (DA) were isolated from the rumen of sheep (Slovak Merino breed) and cultivated anaerobically in the presence of bacteria in caudatum-type medium. To test the effect of soluble linoleic acid (LA) on protozoan growth, both ciliate species were supplemented with LA (1.51 μg/L) on the day of dilution over a 30-day period. Twenty-four-hour fermentation parameters were examined on both ciliate cultures and their respective bacterial fractions. Ciliate counts of both EC and DA cultures were not significantly affected by supplemented LA. The major impact of the soluble form of LA supplement was found in the bacterial fractions of both ciliate cultures. LA supplementation had a greater effect on fermentation parameters and fatty-acid contents in the EC experimental groups than in the DA groups. Our results suggest that experimental rumen ciliates and their associated bacterial populations had different metabolic responses to the tested form and concentration of supplemented LA.

The cellular fatty acid composition of Acanthamoeba castellanii, a unicellular bacteriovorous organism, was reinvestigated. Lipids from amoebae grown axenically in proteose peptone-yeast extract-glucose medium were extracted with chloroform–methanol and separated by silicic acid column chromatography into non-polar and polar fractions. The fatty acid composition of the lipids and the double-bond position of the unsaturated acids have been determined by capillary gas chromatography-mass spectrometry (GC-MS) of their corresponding methyl esters, 2-alkenyl-4,4-dimethyloxazoline (DMOX) derivatives and dimethyldisulfide (DMDS) adducts. Evidence is given that lipids from A. castellanii in addition to the three already identified saturated straight chain fatty acids: tetradecanoic (C14:0), hexadecanoic (C16:0), octadecanoic (C18:0), and six preponderant unsaturated fatty acids: hexadecenoic (C16:1 Δ7), octadecenoic (C18:1 Δ9), octadecadienoic (C18:2 Δ9,12), eicosadienoic (C20:2 Δ11,14), eicosatrienoic (C20:3 Δ8,11,14), and eicosatetraenoic (C20:4 Δ5,8,11,14), contain additionally four very long chain unsaturated fatty acids: octacosenoic (C28:1 Δ21), octacosadienoic (C28:2 Δ5,21), triacontadienoic (30:2 Δ21,24), and triacontatrienoic (C30:3 Δ5,21,24) previously unreported in lipids of A. castellanii. These new long chain fatty acids account for approximately 25% of total fatty acids. To our knowledge, this is the first report of very long chain polyenoic fatty acids present in lipids extracted from A. castellanii cells.

We assessed the biological activity of a crude extract, a mixture of several fractions, and a pure compound obtained from Piper ovatum Vahl against promastigote and amastigote forms of Leishmania amazonensis. The medicinal plant P. ovatum is used popularly as an anesthetic and anti-inflammatory. This study included the extraction process and bioassay-guided fractionation by the adsorption chromatography and Sephadex LH-20 method. A progressive increase in the antileishmanial effect was observed in the course of fractionation. The 50% inhibitory concentration (IC50) for dichloromethane-ethyl acetate (1:1 v/v) fraction was 2.1 μg/ml and 24 μg/ml; mixture of piperovatine: piperlongumune (2:3) 0.9 μg/ml and 24 μg/ml; piperovatine (1) 9.5 μg/ml and 10 μg/ml; and piperlonguminine (2) 2.5 μg/ml and 9.0 μg/ml, for promastigote and amastigote forms, respectively. Cytotoxicity analysis indicated that these toxic concentrations were much higher for J774G8 macrophages and Vero cells than for the protozoans. The mixture of piperovatine: piperlongumune (2:3) showed important antiprotozoal activity against the amastigote and promastigote forms of L. amazonensis, and it produced morphological changes in promastigotes and amastigotes at 0.9 μg/ml and 24 μg/ml (50% growth inhibition concentration), respectively, including intense cytoplasmic vacuolization, mitochondrial swelling, and mitochondrial damage, as revealed by transmission electron microscopy.

Two new myxozoan species – Myxobolus analfinus sp. n. and Myxobolus debsantus sp. n. are described from Heteropneustes fossilis (Bloch) and Catla-Rohu hybrid carp [Male parent fish Catla catla (Hamilton Buchanan) × Female parent fish Labeo rohita (Hamilton- Buchanan)], respectively. Spores of Myxobolus analfinus are oval with slightly acuminate anterior end and large prominent intercapsular notch. On the other hand, in Myxobolus debsantus spores are spherical to oval with intercapsular notch and posterior sutural markings. In both the myxobolid species polar capsules are unequal. The detailed light microscopic and SEM structures and measurements of these two myxozoans are given.