We investigated the status of various Neokeronopsis populations, using protargol-impregnated type material, a new Chinese population, and literature data. This resulted not only in the recognition of a new species, Neokeronopsis asiatica, but also in upgrading Afrokeronopsis from subgenus to genus level. The genera Neokeronopsis and Afrokeronopsis differ mainly in the buccal depression (absent vs. present) and in the midventral cirri between proter and opisthe, which are either retained (Afrokeronopsis) or transformed into cirral anlagen (Neokeronopsis). Neokeronopsis asiatica nov. spec. differs from N. spectabilis (Kahl, 1932) by the following features: body size (~ 300 × 120 μm vs. 400 × 170 μm); posterior body end (acute with distinct indentation at site of caudal cirri vs. broadly rounded and without or indistinct indentation); posterior end of marginal rows (ending at different vs. same or similar level); dorsal kinety 1 (continuous vs. fragmented); and the size of the bases of the adoral membranelles (largest membranelles on average 18 μm vs. 29 μm wide). Improved diagnoses are provided for the family Neokeronopsidae and the genera contained therein, viz., Neokeronopsis, Afrokeronopsis, and Pattersoniella. Our study shows the importance of depositing type and voucher material in recognized repositories. Only this will allow future researchers to restudy the populations, for the sake of improved taxonomic and biogeographic knowledge.

Paraphysomonas vestita is a unicellular, colorless, silica-scaled chrysophyte that plays an important ecological role in freshwater microbial communities as a consumer of prokaryotic and eukaryotic prey. There is little biogeographical information for this minute protist despite its significant role in aquatic food webs. In addition, the phylogenetic relationship of P. vestita to other taxa is unclear as P. vestita may be polyphyletic or a cryptic species complex. In this study, a clonal isolate from a freshwater sample of Laguna de Bay, Philippines was subjected to morphological study by electron microscopy and its small subunit ribosomal RNA (SSU rRNA) gene was sequenced. Morphological studies showed that the isolate possesses two unequal flagella emerging from the anterior part of the cell. Negative staining revealed the structure of the scales which consist of a baseplate with slightly thickened rim. The narrowing spine arises from the center of the baseplate. These results agree with previously studied isolates of P. vestita. The 18S rRNA gene sequence of the isolate had a very high similarity (99%) to P. vestita strain PV10. Phylogenetic analysis also showed that the isolate clustered with other Paraphysomonas sequences with high bootstrap support. Phylogenetic studies confirmed that P. vestita may be polyphyletic. No studies on the ultrastructure and phylogeny of a silica-scaled chrysophyte isolated in the Philippines have been reported so far. Results from this study may contribute to further ultrastructural and phylogenetic studies on aquatic flagellates and specifically to a revision of this potentially polyphyletic species.

Ultrastructural analyses of fish-infecting myxosporean Henneguya piaractus that is found in the gill lamellae of the freshwater teleost Piaractus mesopotamicus (Characidae) and collected from the Paraguai River, Brazil were described. The parasite occurs within large whitish spherical to ellipsoidal polysporic cysts (up to 2.5 mm long) delimited by a layer of fibroblasts generally connected with some capillaries on the gill epithelium. No external morphological signs of disease were visible in the infected fishes. The tailed spores measured 61.5 ± 0.91 (60.2–62.6) μm in total length and ellipsoidal spore body 21.1 ± 0.62 (20.6–21.9) μm long, 6.7 ± 0.40 (6.2–7.3) μm wide and 2.5 ± 0.54 (2.0–3.1) μm thick. The spore wall was about 97 nm of thickness and consisted of a thin electron-dense exospore and a thick electron-lucent endospore with about 85 nm of thickness. The tailed spores were composed of two equal–sized shell valves adhering together along the straight suture line each having in continuity a equal caudal tapering tail measuring 40.5 ± 1.02 (38.7–43.1) μm in length. Two symmetric polar capsules measured 9.8 ± 0.28 (9.3–10.1) μm long and 1.9 ± 0.37 (1.4–2.4) μm wide, each having a polar filament with 10–11 (rarely 12) coils

A new species of Isospora is described from the fecal contents of the white-chinned woodcreeper, Dendrocincla merula merula from Guyana and Dendrocincla merula barletti from Peru. Sporulated oocysts are subspherical to ovoid, 19.2 × 16.5 (15–23 × 14.5–19) μm, with a smooth, colorless, bilayered wall. The average shape index is 1.2. No micropyle or oocyst residuum are present, but the oocysts contain one polar granule. Sporocysts are ovoid, 12.9 × 8.3 (12–14 × 7–10) μm, average shape index of 1.7 with a smooth, single layered wall and composed of a small, knoblike Stieda body and a slightly larger, bubble shaped substieda body. The two sporocysts each contain a compact residuum composed of coarse, non-uniform granules and four randomly arranged, vermiform sporozoites each with a terminal refractile body and a centrally located nucleus. DNA sequences representing ITS-1 and ITS-4 regions of the 5.8S rDNA gene from the two isolates were amplified and compared. In addition to the two isolates showing similar morphological characteristics, they also had identical nucleotide sequences for the ITS-1 and ITS-4 regions of the 5.8S ribosomal gene.

The type species of the genus Duboscqia Perez, 1908 (Opisthokonta, Microspora), D. legeri is a pathogen of termites. It was found again in Zootermopsis angusticollis in British Columbia and the material is used for emendation of data on ultrastructures of this old genus. The sporogony of this microsporidian ends with 16 oval spores closed in sporophorous vesicles. The isofilar polar filament coiled in 13 coils, the arched anchoring disc and the polaroplast with tightly packed lamellae are typical for the ultrastructures of uninucleate spores. The sporophorous vesicle is persistent. The microsporidian infects cyst-like lobes of the fat body hanging free in the body cavity. Relations to other related genera are discussed.

Presence, uptake and production of serotonin and its effect on the production of other hormones were studied using immunocytochemical flow cytometric method. In a serotonin (10–12 M) containing medium up to 15 min. serotonin level does not elevate in the cells, but after 30 min. there is a significant elevation which remains till 4 h. In cells starved in salt solution the elevation is higher which calls attention to the effect of (starvation) stress. Using four enzyme blockers tryptophane hydroxylase inhibitor PCPA decreased (in serotonincontaining medium) and MAO B blocker deprenyl increased serotonin content, while serotonin reuptake inhibitor fluoxetine and MAO-A blocker clorgyline were ineffective. Extremely low concentrations of serotonin (10–15 M in case of histamine and 10–18 M in case of ACTH and T3) in the milieu was sufficient for increasing hormone (ACTH, T3, histamine) levels inside the cells. In conclusion; serotonin can be taken up by the cells and can be produced by induction, as Tetrahymena has enzymes for building it up and decomposing it. For synthesizing serotonin; basic molecules from outside are not needed. Serotonin in a minute amount can induce production of different hormones.

Three putative ciliate fossils were described from the Neoproterozoic Doushantuo Formation in China: Eotintinnopsis, Wujiangella, and Yonyangella. The identity of these fossils is important for our understanding of the origins and early morphological evolution within ciliate clades. Here we compare the homology of the fossil characteristics with those in their proposed ciliate relatives. Eotintinnopsis resembles a tintinnid, but its feathery tentacle-like apical structure is probably not homologous within any known ciliate. Wujiangella presents homology issues with the size and distribution of its putative somatic cilia. Yonyangella appears to be a suctorian with its tentaclelike structures, but the presence and size of its putative somatic cilia pose homology issues. We suggest that these three fossils are likely to be taphonomically and diagenetically distorted and altered acritarchs. These alterations include secondary mineral encrustations on the interiors of vesicles, the crushing, folding and other distortions of the vesicles, the bending and crushing of the acritarch spines, and the preservation of organic material in and outside of the cysts. The earliest known ciliate fossil remains a tintinnid that occurs in the Ordovician of Kazakhstan.

The time of onset of survival of ciliate protozoa in the equine hindgut in new born foals was investigated. Daily faecal samples were collected from 6 new-born foals and studied under a microscope for examples of ciliates within the samples. The results of this study show that ciliates are first seen in faecal samples from the foal on day 5 post partum although these appeared to be voided and were assumed to be non-viable. However, by the following day the ciliates collected seen in the faecal samples appeared to be intact and were assumed to be viable. This observation is 5 days earlier than ciliates have previously been observed in faeces collected from the digestive tract of newborn foals.