Molecular characterization of waterborne protozoa in surface water and sediment in Brazil: a taxonomic survey of ciliated protozoa and their correlation with Giardia duodenalis and Cryptosporidium spp.

The detection of Giardia duodenalis and Cryptosporidium spp. was performed, along with the identification of the ciliated protozoa biodiversity, to evaluate the correlation between these protozoa in freshwater quality monitoring. Water and sediment samples from two sites in the Atibaia River (Campinas, São Paulo, Brazil) were collected monthly for 2 years (n = 96). Pathogenic protozoa in water and sediment were detected by using immunomagnetic separation, followed by visualization by immunofluorescence assay (IFA). All positive aliquots in IFA were subjected to DNA extraction and subsequently nested PCR. Qualitative (in vivo observation and silver impregnation) and quantitative (in vivo enumeration) analyses were performed for the ciliated protozoa. Giardia cysts were detected in 62.5% of the surface water samples and Cryptosporidium spp. in 25.0%. In the sediment, cysts were detected in 35.4% samples and oocysts in 16.6%. A total of 57 samples positive for Giardia cysts were subjected to sequencing, 40 of which were harboring G. duodenalis (24 were characterized as sub-assemblage AII). For ciliated protozoa, 73 taxa belonging to 53 genera were identified over the period of the study. These results revealed a high degree of contamination by waterborne protozoa in the main water source which supplies drinking water for more than one million people in Campinas (São Paulo), highlighting the need for continuous monitoring of this catchment site. In addition, the present study provides important data regarding the sources of the water body degradation, i.e., fecal contamination of human origin, in addition to the survey of the ciliated protozoa.

Multiple stressors in Mediterranean coastal wetland ecosystems: Influence of salinity and an insecticide on zooplankton communities under different temperature conditions.

Temperature increase, salinity intrusion and pesticide pollution have been suggested to be among the main stressors affecting the biodiversity of coastal wetland ecosystems. Here we assessed the single and combined effects of these stressors on zooplankton communities collected from a Mediterranean coastal lagoon. An indoor microcosm experiment was designed with temperature variation (20 °C and 30 °C), salinity (no addition, 2.5 g/L NaCl) and the insecticide chlorpyrifos (no addition, 1 µg/L) as treatments. The impact of these stressors was evaluated on water quality variables and on the zooplankton comunity (structure, diversity, abundance and taxa responses) for 28 days. This study shows that temperature is the main driver for zooplankton community change, followed by salinity and chlorpyrifos. The three stressors contributed to a decrease on zooplankton diversity. The increase of temperature contributed to an increase of zooplankton abundance. Salinity generally affected Cladocera, which resulted in a Copepoda increase at 20 °C, and a reduction in the abundance of all major zooplankton groups at 30 °C. The insecticide chlorpyrifos affected primarily Cladocera, altough the magnitude and duration of the direct and indirect effects caused by the insecticide substantially differed between the two temperature scenarios. Chlorpyrifos and salinity resulted in antagonistic effects on sensitive taxa (Cladocera) at 20 °C and 30 °C. This study shows that temperature can influence the direct and indirect effects of salinity and pesticides on zooplankton communities in Mediterranean coastal wetlands, and highlights vulnerable taxa and ecological responses that are expected to dominate under future global change scenarios.

In vitro toxicity of isolated strains and cyanobacterial bloom biomasses over Paramecium caudatum (ciliophora): Lessons from a non-metazoan model organism.

Cyanobacteria have been considered a major global threat because of their widespread ability to proliferate and contaminate inland and marine waters with toxic metabolites. For this reason, to avoid risks to humans and environmental health, regulatory legislation and guidelines have been established based on extensive toxicological data. However, most of what is known in this field come from works on microcystin (MC) variants, which effects were almost exclusively tested in metazoan models. In this work, we used acute end-point toxicological assays and high-resolution hybrid quadrupole time-of-flight mass spectrometer coupled with electrospray ionization source (ESI-Q-TOF-MS) analyses to evaluate the deleterious impact of aqueous extracts prepared from cultures of cyanobacteria and environmental bloom biomasses over a non-metazoan model organism, the cosmopolitan fresh/brackish water unicellular microeukaryote, Paramecium caudatum (Ciliophora). Our data suggest that all extracts produced time-dependent effects on P. caudatum survival, irrespective of their metabolite profile; and that this ciliate is more sensitive to extracts containing microginins than to extracts with only MCs, stressing that more toxicological investigations should be performed on the environmental impact of neglected cyanotoxins. Further, our data provide evidence that P. caudatum may be more sensitive to cyanotoxins than vertebrates, indicating that guidelines values, set on metazoans are likely to be inaccurate to protect organisms from basal food web positions. Thus, we highly recommend the widespread use of microeukaryotes, such as ciliates in environmental risk assessment frameworks for the establishment of more reliable cyanotoxin monitoring guideline values.

Diversity and Distribution of Peritrich Ciliates on the Snail Physa acuta Draparnaud, 1805 (Gastropoda: Physidae) in a Eutrophic Lotic System.

Bianca Sartini, Roberto Marchesini, Sthefane D ´ávila, Marta D'Agosto, and Roberto Júnio Pedroso Dias (2018) Freshwater gastropods represent good models for the investigation of epibiotic relationships because their shells act as hard substrates, offering a range of microhabitats that peritrich ciliates can occupy. In the present study we analyzed the community composition and structure of peritrich epibionts on the basibiont freshwater gastropod Physa acuta. We also investigated the spatial distribution of these ciliates on the shells of the basibionts, assuming the premise that the shell is a topologically complex substrate. Among the 140 analyzed snails, 60.7% were colonized by peritrichs. We observed seven peritrich species: Epistylis plicatilis and Epistylis sp. (Epistylididae); Opercularia articulata (Operculariidae); Carchesium polypinum, Vorticella campanula and Vorticella sp. (Vorticellidae) and Thuricola kellicottiana (Vaginicollidae). We observed a high prevalence of epibiosis (> 60%) when all species of ciliates were considered conjunctly. However, the prevalence was low (1-58%) when each species was considered separately, reflecting their aggregate distribution pattern. The most prevalent species were Epistylis sp. (58.60%), Vorticella sp. (14.30%) and O. articulata (13.60%). Although the epibionts were distributed through the shell's entire extension, we observed greater values of abundance, density, diversity and dominance on the dorsal surface. Only Epistylis sp. was widely distributed on the ventral surface. We also observed that the peritrichs predominantly occupied the areas of the shell delimited by the sutures. We interpreted these distribution patterns considering that the peritrichs select their attachment sites under pressures related to basibiont behavior, physical forces that may dislocate them and protective characteristics of the shell's areas.

Redescription of Licnophora chattoni Villeneuve-Brachon, 1939 (Ciliophora, Spirotrichea), associated with Zyzzyzus warreni Calder, 1988 (Cnidaria, Hydrozoa).

Licnophora chattoni, found in association with Zyzzyzus warreni, a tubulariid hydroid epizoic in sponges from São Sebastião (SP, Brazil), is redescribed and illustrated using light and electron microscopy. The ciliate has a flexible, transparent body formed by an oval anterior region linked to the posterior basal disc via a flexible neck region. Numerous cortical granules are observed scattered throughout the body and densely packed along the neck. The adoral zone is formed by about 81 external and 24 infundibular paramembranelles. The paroral membrane, formed by a row of long cilia arranged in monokinetids, extends through a groove in the body to the adhesive disc. Two dorsal kinetids are present along the right body margin and around the neck. The adhesive disc (18µm in diameter) lacks cilia in the area above the velum. The velum covers a row of dikinetids bearing long cilia and four dikineties, two or three of which are interrupted on the ventral surface. Nine to twelve macronuclear nodules connected by isthmuses are distributed in the cytoplasm, plus two nodules located in the adhesive disc and between those there is an ovate micronucleus.