Naked amoebae are among the most abundant soil protists, especially in highly productive soils. Their capacity to produce cysts during unfavorable growth periods, especially drying, enhances their survivability as resting stages and promotes dispersal by wind and air currents. However, the dynamics of their cycles of encystment and active growth are poorly documented. Using a recently developed culture observation method, including a dried preparation stage to detect encysted amoebae, data are presented on the ratios of active and encysted stages of naked amoebae based on field samples from diverse terrestrial sites differing in plant cover and moisture content during spring and summer months 2008 at a location in northeastern U.S.A. Percentage of encysted amoebae varied between 32% and 100% depending on locale and moisture content. Carbon content of the cysts (estimated from recently excysted individuals) relative to trophic stages varied between 22% and 100% at these same locales. Laboratory experimental studies of winter soil samples, that were cultured at 25oC to promote amoeba community growth, indicated that a dynamic relationship exists between active and encysted stages during proliferation with varying ratios depending on the moisture content and qualities of the soil at the collection site, thus suggesting a revised model as presented here of the encystment-excystment cycle for populations during a growth succession.

The Biology of the Coccidia (Apicomplexa) of Snakes of the World: A Scholarly Handbook for Identification and Treatment, Donald W. Duszynski and Steve J. Upton, 430 pages, Illustrated. CreateSpace Inc., a DBA of On-Demand publishing LLC, an Amazon.com Company, Price $70.00 USD (https://createspace.com/3388533). ISBN: 1448617995.

The aim of this study was to determine the prevalence of Acanthamoeba in the domestic water supply in Huntington, West Virginia (U.S.A.) and the factors that may contribute to their presence or absence. One hundred sixty-two one liter tap water samples were collected over eight months. Amoebae in the samples (cysts or trophozoites) were harvested by passively filtering onto 5 μm pore size filters and enriching for amoebae on non-nutrient amoeba saline agar plates seeded with Escherichia coli for cultivation. Thirteen percent of all samples were positive for amoebae and 9.3% were positive for the amoeba of interest, Acanthamoeba. Chlorine levels were determined for samples at the time of collection, yielding a mean level of 1.56 mg l–1 chlorine in the distribution system ca. 8 kilometers from the water treatment plant. Cysts and trophozoites of Acanthamoeba clonal isolates were found to tolerate up to 50 mg l–1 and 4 mg l–1 chlorine respectively. This study showed that Acanthamoeba were present in the domestic water supply in Huntington, WV and although no attempt was made to count cells in liter samples, their frequency of occurrence (9.3%) and failure to be present in all replicates, suggests they were present at background levels of perhaps a few cells per five liters. This is only the second U.S. study to consider amoebae in tap water and is unique since the source water was river water. Acanthamoeba trophozoites and cysts were able to withstand levels of chlorine higher than those typically found in tap water suggesting they may be present in either form in the distribution system. Acanthamoeba are opportunistic pathogens capable of causing eye infections and their presence in tap water is a potential risk factor for susceptible individuals, particularly contact lens wearers who may use tap water to clean lenses and storage cases.

We investigated changes in diversity and density of testate amoebae in epiphytes of trees in tropical montane rain forests of southern Ecuador. Local – microscale [height on tree trunk of 0 (base of tree trunk), 1 and 2 m; TH I, TH II and TH III, respectively] and regional – macroscale (forests at 1000, 2000 and 3000 m) changes were investigated. At the macroscale diversity and density of testate amoebae peaked at 2000 m. At the microscale diversity reached a maximum at TH I, whereas density reached a maximum at TH III. The percentage of empty shells at the macroscale was at a maximum at 2000 m and at the microscale at TH I, whereas the percentage of live cells was at a maximum at 3000 m and at TH III. The diversity of testate amoebae in epiphytes found in the present study was high (113 species). However, only two to nine species were dominant representing 54–85 percent of total living testate amoebae. The results suggest significant variations in density and diversity of testate amoebae at both the micro- and macroscale. However, for testate amoebae density the macroscale appears most important whereas changes in diversity are more pronounced at the microscale

Testate amoebae are routinely used as paleoenvironmental indicators. However, considerable variability occurs in test morphology, even within commonly identified taxa. Relationships between morphological variability and environmental conditions might be useful in paleohydrological studies of peatlands, assuming good preservation of characteristics. Hyalosphenia papilio is a common taxon, well preserved in Sphagnum peatlands, that displays variability in the number of pores on the broad side of the test. We assessed whether variability in pore number was related to substrate moisture by comparing the abundance of individuals with different numbers of pores to measured water-table depths at 67 sites in North America. Results indicated that the abundance of individuals with higher numbers of pores increased in wetter conditions. Individuals with 2 pores were relatively widespread, although they dominated drier habitats. Transfer functions developed with and without pore-number quantification suggest that when communities contain abundant individuals with greater than 2 pores, water-table depth reconstructions can be improved by including pore-number information. Results have implications for peatland paleohydrological studies and suggest that greater exploitation of morphological variability could improve testate amoeba-based reconstructions of past environmental change.

A new sphagnicolous species of the genus Nebela isolated from wet Sphagnum mosses gathered at Vitosha Mountain (Bulgaria) is described. Shell ultrastructure and morphological variability of Nebela golemanskyi sp. nov. are investigated using scanning electron microscopy. The newly described species is characterized by its almost uncompressed shell and by its large, rounded, voluminous and hollow structural elements (idiosomes). The analysis of the variation coefficients shows that the studied population is too homogeneous and all measured morphological characters are feebly variable (CV range from 3.28% to 5.02%). Size frequency distribution analysis indicates that N. golemanskyi is size-polymorphic species, characterized by not well-expressed main-size class in favour of many subsidiary classes. A biometrical and morphological comparison between N. golemanskyi and N. speciosa is made.

The morphology, infraciliature, and silverline system of three marine scuticociliates, Uronema marinum Dujardin, 1841, U. heteromarinum nov. spec. and Pleuronema setigerum Calkins, 1902, isolated from coastal waters off Qingdao, China, were investigated using living observation and silver impregnation methods. Due to the great confusion in the species definition of the well-known species U. marinum, we have documented a detailed discussion/comparison and believe that most of the confusion is due to the fact that at least 2 closely-related sibling morphotypes exist which are often not recognized. Based on the data available, U. marinum is strictly defined as follows: marine Uronema ca. 30 × 10 μm in size, with truncated apical frontal plate and smooth pellicle, extrusomes inconspicuous, cytostome located equatorially, 12–14 somatic kineties and one contractile vacuole pore near posterior end of kinety 2. Uronema heteromarinum nov. spec. resembles U. marinum but can be distinguished morphologically by its notched pellicle with conspicuous extrusomes and reticulate ridges, the 15–16 somatic kineties, widely separated membranelle 1 and membranelle 2, as well as the subequatorially positioned cytostome. Based on the Qingdao population, an improved diagnosis for the poorly known Pleuronema setigerum is: marine slender oval-shaped form, in vivo about 40–50 × 15–20 μm; 3–5 preoral kineties and 14–22 somatic kineties; membranelle 1 and 3 three-rowed, and posterior end of M2a ring-like. The small subunit (SSU) rRNA gene for all three organisms were sequenced and analyzed with standard methods.

Mantoscyphidians occur in high numbers on the gills of South African Haliotis and limpet species. This provided the ideal opportunity to study asexual and sexual reproduction, for the first time in different African Mantoscyphidia Jankowski, 1985 populations. Descriptions of the reproductive processes found in scyphidiid peritrichs were until now, mostly based on line drawings. Scanning electronand light microscopy contributed uniquely, in providing detail information regarding binary fission, telotroch formation and conjugation. Mantoscyphidia spadiceae Botes, Basson and Van As, 2001 shed the most light on binary fission. Micronuclear division occurred first with the plane of fission already evident and macronuclear cleavage ended just before final separation took place. Fission is not complete until a small string of pellicle that joins the daughter cells finally separates. Information on telotroch development was gathered from M. branchi Van As, Basson and Van As, 1998 and M. spadiceae populations. Telotrochs were between 36.7 and 38.6% shorter than live, extended mantoscyphidians and their swimming action resembled mobiline peritrichs. Mantoscyphidia branchi populations also proved to be most useful for conjugation studies. Conjugation included three progamic nuclear divisions and preceded synkaryon formation and two metagamic nuclear divisions. The process required 24 hours to be completed.

The ultrastructure and molecular phylogeny of a new microsporidium Mrazekia macrocyclopis sp.n., a parasite of the copepod Macrocyclops albidus (Jur.) in North-West of Russia are described. All stages of its life cycle are diplokaryotic. Fresh spores are rod-shaped and 7.3–10.5 × 1.6–2.3 μm in size. Spore ultrastructure is typical of Mrazekia. The polar tube consists of the anterior clavate manubrium followed by a thin filament arranged in 3.5–4.5 nearly vertical coils. Spores are enclosed in individual sporophorous vesicles. SSU rDNA sequence analysis showed attribution of the new species to a cluster of microsporidia infecting insects (Cystosporogenes, Endoreticulatus), microsrustaceans (Glugoides), vertebrates (Vittaforma) and ciliates (Euplotespora) nested within the clade IV sensu Vossbrinck, Debrunner- Vossbrinck (2005). Mrazekia macrocyclopis is not therefore closely related to Bacillidium vesiculoformis, another microsporidium with rod-shaped spores, and the polyphyletic nature of the family of Mrazekiidae is obvious.