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Testate amoebae are a polyphyletic assemblage of at least three major, unrelated taxonomic groups of unicellular amoeboid eukaryotes exhibiting a test. The focus on testate amoebae in scientific research has greatly increased in the past 20 years: from an average of about 5 papers a year in the mid-1990s to the current rate of more than 50 papers published yearly. The application range of these organisms is rapidly expanding as well: from the traditional fields of environmental monitoring and paleoecology, to forensic sciences and ecotoxicology studies. These developments are nevertheless strongly dependent on reliable taxonomy and nomenclature. However, scientometric data reveal that despite an ever-increasing necessity for the use of names (the product of taxonomy), the corresponding effort has not been achieved for improving testate amoebae systematics. As a consequence, inaccurate taxonomy yields to misinterpretations in the diversity of the organisms and to potentially incorrect conclusions. These and related problems are discussed in this study, highlighting the outcome of poor taxonomic expertise in accurate classification and phylogeny of testate amoebae, and the consequences derived from it. Additionally, this study is aimed to discuss the current status of testate amoebae classification, and to present all nomenclature and taxonomic changes in higher and lower taxonomic levels of testate amoebae, as a result of recent molecular reconstructions. Finally, we conclude with a list of the needs and suggestions toward a unified and modernized taxonomy of testate amoebae. [ABSTRACT FROM AUTHOR]

Climate, fire, and human activities strongly affected the development of vegetation communities during the Holocene, yet the relative importance of these individual factors remains unclear in many areas. This paper presents new multi-proxy records of environmental change for the Meshchera Lowlands (the central part of the East European Plain) during the Holocene. Changes in regional vegetation during the Mid- and Late Holocene were influenced by climate, fire regime and human impact, as indicated by pollen, plant macrofossil, charcoal and testate amoebae analysis from several peat cores, along with reconstruction of tree cover from pollen assemblages. Since 8500 cal yr BP, the vegetation history represented a series of consecutive phases of birch, birch-pine and pine-broadleaf forests, with introduction of spruce after 2500 cal yr BP. Maximal abundance of broadleaf tree species was detected from 4700 to 2000 cal yr BP. Vegetation dynamics were strongly influenced by human activity since 1400 cal yr BP. High fire frequency was recorded for the periods 8500–4500 cal yr BP and 3500–2000 cal yr BP, when the fire return interval varied from 40 to 80 years. Since 2000 cal yr BP, the fire return period exceeded 500 years suggesting a significant decline in fire frequency during the last two millennia. [ABSTRACT FROM AUTHOR]

Outbreak incidents raise the question of whether the less frequent aetiological agents of outbreaks are really less frequent in water. Alternatively, waterborne transmission could be relevant, but the lack of attention and rapid, sensitive methods to recover and detect the exogenous stages in water may keep them under-recognized. High quality information on the prevalence and detection of less frequent waterborne protozoa, such as Cyclospora cayetanensis , Toxoplasma gondii , Isospora belli , Balantidium coli , Blastocystis hominis , Entamoeba histolytica and other free-living amoebae (FLA), are not available. This present paper discusses the detection tools applied for the water surveillance of the neglected waterborne protozoa mentioned above and provides future perspectives. [ABSTRACT FROM AUTHOR]

Although the presence of test is the most fundamental synapomorphy of arcellinid lobose amoebae, the significance of tests in maintenance of the biological functions of these organisms is still largely unclear. This paper demonstrates the effect of the artificial test removal on the behaviour, ultrastructure and reproduction of the testate lobose amoebae belonging to the two species of the genus Arcella . The studied cells can survive after artificial removal of their test, and many specimens are capable of building a test de novo. We investigated this process and found that test-free cells of Arcella in culture remained alive for weeks; they are able to move and feed, but never undergo normal cell division accompanied by mitosis. Test-free cells can restore the test in three different ways: (1) building almost normal test; (2) building a very small single-chambered test; (3) building a test which consisted of several small chambers attached to each other. Although newly constructed tests are abnormal, cells restore shape, size and other characteristic features of the test in the next one or two generations of descendants. The results obtained suggest that the test may be critically important for completing a life cycle of an amoeba. [ABSTRACT FROM AUTHOR]

The present paper describes two new species of lobose amoebae belonging to the family Paramoebidae within the order Dactylopodida: Pseudoparamoeba microlepis n. sp. and Korotnevella fousta n. sp. Among them, P. microlepis formally fits the diagnosis of the genus Korotnevella , because it has scales and lacks a parasome. At the same time its 18S rDNA gene sequence robustly groups with Pseudoparamoeba pagei and never branches among those of Korotnevella spp. Korotnevella fousta in 18S rDNA tree groups among other species of the genus Korotnevella . It has uniform scales with an elliptical basal plate and spine arising from its central part and surrounded by an “inverted skirt” structure. These findings show that the current differentiation between the genera Korotnevella and Pseudoparamoeba based on the presence of scales is not entirely valid. At the moment only molecular data can reliably differentiate these two genera. [ABSTRACT FROM AUTHOR]

High resolution palaeoenvironmental records in Far-Eastern Russia are rare, and the Kamchatka Peninsula is among the least studied areas of the region. This paper describes a record spanning the last ca. 11,000 yr, obtained from a bog in the southern part of Kamchatka. The radiocarbon dated core was analysed for pollen, testate amoebae, charcoal and loss-on-ignition (LOI). The vegetation during the early Holocene was dominated by grasses (Poaceae), birch ( Betula ) and heath (Ericaceae p. p.). Around 10,300 cal yr BP there was a substantial change in the vegetation cover to shrub alder ( Alnus viridis s.l.) stands with sedges and ferns (Polypodiophyta) as well as herbs such as meadow rue ( Thalictrum ) in the understory. In the surroundings of Utka peatlands started to form. The variations in the vegetation cover were most probably caused by climatic changes. At the beginning of sediment accumulation, before 10,300 cal yr BP, the composition of the vegetation points to cooler summers and/or decreased annual precipitation. Around 10,300 cal yr BP, changes in vegetation occurred due to rising temperatures and/or changed water regimes. Increased abundancies of dry indicating testate amoebae after 9100 cal yr BP point to intermediate to dry soil conditions. Between 8600 and 7700 cal yr BP tree alder ( Alnus incana ) was widely spread at the site which probably indicates optimal environmental conditions. The tephra layer at 381–384.5 cm (ca. 8500 cal yr BP) produces a strong impact on the testate amoebae assemblages. At 7700 cal yr BP there was a sudden drop of A. incana in the local vegetation. From this time on, A. incana and also A. viridis decrease continuously whereas Betula gradually increases. The upper part of the sequence (after 6300 cal yr BP) shows higher abundancies of meadowsweet ( Filipendula ) and sweet gale ( Myrica ) pollen. After 6300 cal yr BP, changes in testate amoebae demonstrate variable soil moisture conditions at the site. Between 3700 and 1800 cal yr BP, wet conditions dominate as dry indicating testate amoebae decrease. After 1800 cal yr BP soil conditions become more variable again but this time with dry dominating testate amoebae. In contrast to surrounding regions, there is no evidence of trees such as spruce or larch growing in the surroundings of the site even though those trees are characteristic of many eastern Siberian sites. This difference might be because of the maritime influence of the Okhotsk Sea. Even dwarf pine ( Pinus pumila ), which is currently widely dispersed in northern Kamchatka, became part of the local vegetation only during the last 700 yr. [ABSTRACT FROM AUTHOR]

This paper describes a new genus, Cunea n. g., of marine naked amoebae with two cryptic species, Cunea profundata and Cunea thuwala , isolated from distant localities in the ocean and different depths (Brazilian abyssal plain, Western Atlantic Ocean, depth >5 km and the Red Sea off the Saudi Arabian coast, depth ca. 58.7 m). Both species are very similar to each other in the set of light microscopic and ultrastructural characters and might be described as a single species, yet their genetic divergence based on 3 molecular markers (small-subunit ribosomal RNA, actin and cytochrome c oxidase subunit 1) corresponds to the level of variation typically observed between different morphospecies of Amoebozoa. In addition, the studied strains differ strongly in their temperature tolerance ranges, C . profundata isolated from the cold Atlantic deep-sea habitat being able to reproduce under lower temperatures than C . thuwala isolated from the warm Red Sea benthos. Molecular phylogenetic analysis based on SSU rRNA gene shows that the new genus robustly branches within the Dactylopodida, but forms an independent clade within this order that does not group with any of its known genera. [ABSTRACT FROM AUTHOR]

Abstract: Testate amoebae have been used widely as a proxy of hydrological change in ombrotrophic peatlands, although their response to abiotic controls in other types of mire and fenland palaeo-environments is less well understood. This paper examines the response of testate amoebae to hydroseral and other environmental changes at Mer Bleue Bog, Ontario, Canada, a large ombrotrophic peatland, which evolved from a brackish-water embayment in the early Holocene. Sediments, plant macrofossils and diatoms examined from a 5.99 m core collected from the dome of the bog record six stages of development: i) a quiet, brackish-water riverine phase (prior to ca. 8500 cal BP); ii) a shallow lake (ca. 8500–8200 cal BP); iii) fen (8200–7600 cal BP); iv) transitional mire (7600–6900 cal BP); v) pioneer raised mire (6900–4450 cal BP); and vi) ombrotrophic bog (4450 cal BP-present). Testate amoebae, notably small (<25 μm diameter) specimens of Centropyxis aculeata type, first appear in low abundances in sediments ascribed to the lacustrine phase. Diatoms from the same horizons record a shallowing in water depth, a decline in salinity and the development of emergent macrophytic vegetation, which may have provided favourable conditions for testate amoeba colonization. The testate amoeba communities of the inferred fen phase are more diverse and include centropyxids, cyclopyxids, Arcellidae and Hyalospheniidae, although the assemblages show some differences to those recently reported in modern European fen environments. The Fen–Bog Transition (FBT) is also dominated by C. aculeata type. The change in testate amoeba communities around this key transition is apparent in the results of Detrended Correspondence Analysis (DCA), and appears to reflect a latent nutrient gradient and a secondary moisture gradient. DCA analyses of plant macrofossil remains around the FBT show a similar trend, although the sensitivity of the two proxies to the inferred environmental changes differs. Comparisons with other regional mid-Holocene peatland records confirm the important influence of reduced effective precipitation on the testate amoeba communities during the initiation and development of Sphagnum-dominated, raised bog communities. [Copyright &y& Elsevier]

Abstract: Calibration of proxy climate records is well-established for annually resolved proxies such as tree rings, but it has not been attempted for non-annually resolved proxies such as those from peatland surface wetness records. Several previous studies have suggested that peatland surface wetness is primarily driven by warm season moisture balance and implied a potential for producing calibrated records of deficit or precipitation. This paper presents a high-resolution testate amoebae analysis of a peat record from central Ireland covering the last c.1000 years, and provides the first attempt to produce a calibrated record of past precipitation from a peat record. Past water table depth was reconstructed using a transfer function applied to contiguous samples for the top 1m of the profile. The chronology was constrained by a series of radiocarbon ages (including ‘bomb-spike’ ages) and spheroidal carbonaceous particles. Correlations between reconstructed water tables and meteorological records (1958–1995) of precipitation and deficit were strongly positive and were used to reconstruct precipitation and deficit from the last 1000 years. Validation using earlier meteorological records was hampered by very low peat accumulation rates, but suggested the summer precipitation and deficit reconstructions were more robust than a reconstruction of annual precipitation. The summer precipitation reconstruction suggests that the period AD1400–1850 experienced higher summer rainfall than for much of both the preceding 400 years and the last 150 years. The change in regime from low to high summer rainfall may be attributed to changes in the summer North Atlantic Oscillation. Combined with tree ring and speleothem records of winter NAO, this suggests a major change in seasonality of precipitation in far western Europe between the Medieval Climate Anomaly and the Little Ice Age. The MCA was characterised by dry summers and wet winters, whilst the LIA had wet summers and dry winters. Calibration of peat surface wetness records using meteorological records holds much potential for the future and may lead to improved insights into seasonal precipitation and water balance changes. This study was limited by slow accumulation rates leading to low temporal resolution for the late 19th and early 20th century part of the record. Further development of the technique will require more highly temporally resolved records of change over the whole of the instrumental time period to allow a full calibration and validation approach to be applied. [Copyright &y& Elsevier]

Abstract: Relatively seldom is the same parameter reconstructed from the same site using different proxies, resulting in a persistent problem for palaeoecological studies whereby a reconstruction based on a single-proxy may provide an unequivocal view of the changes in past conditions. Plant macrofossils and testate amoebae are commonly used proxies to reconstruct past changes in peatland surface moisture conditions, but there are no comparisons between quantitative reconstructions based on both techniques. This paper compares two high-resolution late-Holocene quantitative water table (WT) reconstructions based on transfer functions for plant macrofossils and testate amoebae from two boreal peatland sites in Finland and Estonia. The reconstructed WT variation patterns during the last ca. 5000 years are almost identical in directions for both proxies. However, both bog records contain one inconsistent episode when the two proxies indicate different hydrological conditions. In both cases, the testate amoebae reconstruction shows wetter than the average conditions, whereas the plant-based reconstruction indicates drier than the average conditions. Several, possibly simultaneously affecting, reasons can be suggested for mismatches between proxies: 1) the proxies have different response times and sensitivities to hydrological changes, 2) the species-ecology is inadequately known, 3) the modern analogues are poor, 4) the microhabitat dynamics are unpredictable, and 5) the modern data set is too small. Divergences between the proxy records emphasize the fact that single-proxy reconstructions are subject to larger uncertainties than those based on two or more methods. [Copyright &y& Elsevier]

Abstract: In this paper, we investigate the ecology of live (rose Bengal stained) benthic foraminifera collected at 20 stations ranging from 15 to 100m depth in the Rhône prodelta (Gulf of Lions, NW Mediterranean). These sites were sampled in September 2006, five months after the Rhône River annual flood. Statistical analyses based on foraminiferal communities (>150μm) divide our study area into six main biofacies directly related to environmental conditions. Miliolid species are abundant in the relict prodeltaic lobe which is characterised by sand with low organic matter content. Close to the river mouth, the limited oxygen penetration in the sediment combined with important hydro-sedimentary processes constitute stressful conditions for foraminiferal faunas dominated by opportunistic species (e.g. Leptohalysis scottii). With increasing distance from the river mouth, foraminiferal faunas (e.g. Nonionella turgida, Eggerella scabra) adapted to thrive in sediments enriched in Rhône-derived organic matter under more stable hydro-sedimentary conditions appear. In the distal part of the Rhône River influence, benthic species (e.g. Valvulineria bradyana, Textularia agglutinans) living in fine sediment enriched in both continental and marine organic compounds emerge. At the deepest stations located in the south-eastern part of our study area, benthic foraminiferal faunas (e.g. Bulimina aculeata, Melonis barleeanus, Bigenerina nodosaria) are highly diverse, underlining stable environmental conditions characterised by marine-derived organic matter supplies and relatively deep oxygen penetration depth in the sediment. We also compare foraminiferal faunas sampled in September 2006 with communities sampled in June 2005, one month after the Rhône River annual flood (). This comparison suggests that opportunistic species (e.g. B. aculeata, Cassidulina carinata, V. bradyana) have responded to organic matter inputs related to marine primary production in June 2005. [Copyright &y& Elsevier]

Abstract: Testate amoebae are a group of shelled protozoa that occur in high density populations in wet environments. More than 1900 testate amoebae species or subspecies have been reported in published literature over the last 200 years, from many regions of the world. Testate amoebae are classified as Lobosea or Filosea respectively, according to the presence of lobose or filiform pseudopodia. Testate amoebae have proved an interesting group of indicator organisms in palaeoenvironmental studies and have also been used as bioindicators of human impact on ecosystems. Until recently, the testate amoebae of China were unknown to most western scientists, but our knowledge has improved greatly over the past 20 years. This paper summarizes the testate amoebae research in China along with relevant data from other countries in Asia, and provides the necessary context for future research. [ABSTRACT FROM AUTHOR]

Abstract: This paper examines the antiprotozoal activity of the dichloromethane–MeOH extract, fractions and pure compounds from the roots of Geranium mexicanum on Entamoeba histolytica and Giardia lamblia. The result indicated that the extract, organic fraction and a pure flavonoid were active against both protozoa with IC50 values ranging from 1.9 to 79.2μg/ml for Entamoeba histolytica and from 1.6 to 100.4μg/ml in the case of Giardia lamblia. The main active compound was the flavan-3-ol, (–)-epicatechin. In addition, the moderate active compounds (+)-catechin, tyramine and β-sitosterol 3-O-β-d-glucopyranoside, also were isolated. These results support the anecdotal reports for the traditional use of Geranium mexicanum roots in the management of diarrhoea and dysentery, illnesses caused in some cases by enteric protozoa. [Copyright &y& Elsevier]