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1.
Bull Environ Contam Toxicol ; 105(5): 770-776, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32504161

RESUMO

This paper investigates the concentrations of PCBs in the water and sediment media and its bio-concentration in the fish host-parasite bentho-pelagic food chain in Epe lagoon. Samples of water, sediment, plankton, mollusks, fish and intestinal helminth parasites were collected from three stations (Oriba, Imode and Ikosi) in Epe Lagoon. Concentration of total PCBs in the surface water and sediment across the stations ranges from 3.20 to 6.00 ppb and 405.50-860.70 ppb respectively. Imode had the highest concentrations. The plankton bio-concentrates most PCBs in Ikosi (286.70 ppb) followed by Imode concentration (165.40 ppb), then Oribo (92.60 ppb) with total bio-concentration of 544.60 ppb. Surface water temperature negatively and strongly correlates with PCBs in the plankton. The planktons bio-concentrates total PCBs 44 times than that in the surface water. Chrysichthys nigrodigitatus bio-concentrates total PCBs 48 times than that in the surface water. Bioaccumulation of PCBs in human food chain could pose health risk.


Assuntos
Bioacumulação , Peixes-Gato/metabolismo , Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Helmintos/metabolismo , Bifenilos Policlorados/análise , Poluentes Químicos da Água/análise , Animais , Peixes-Gato/parasitologia , Cadeia Alimentar , Água Doce/química , Água Doce/parasitologia , Sedimentos Geológicos/parasitologia , Humanos , Nigéria , Plâncton/metabolismo , Bifenilos Policlorados/metabolismo , Poluentes Químicos da Água/metabolismo
2.
Eur J Protistol ; 73: 125664, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31978632

RESUMO

A new Euplotes species, isolated from abyssal depths (>4000 m) of the North Atlantic Ocean, was described based on morphology, ciliary pattern and molecular data. Euplotes dominicanus sp. n. is characterized by a small body size (29-40 × 17-27 µm in vivo), 18-22 adoral membranelles, 10 frontoventral, five transverse and two left marginal cirri and one caudal cirrus, five or six dorsolateral kineties with 7-9 dikinetids in mid-dorsolateral kinety (DK3), and dorsal silverline system of the double-eurystomus type. Phylogenetic analyses inferred from 18S rRNA sequences show that Euplotes dominicanus sp. n. is most closely related to E. curdsi, with a sequence similarity of 97.6 %. Euplotes dominicanus sp. n. was able to survive hydrostatic pressures up to 500 bar indicating its barotolerance. Metabarcoding data demonstrate the presence of E. dominicanus sp. n. in sediments of several deep-sea basins.


Assuntos
Euplotes/classificação , Filogenia , Oceano Atlântico , DNA de Protozoário/genética , Euplotes/citologia , Euplotes/genética , Sedimentos Geológicos/parasitologia , Pressão , RNA Ribossômico 18S/genética , Especificidade da Espécie
3.
Eur J Protistol ; 72: 125660, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31835237

RESUMO

Several evolutionary lineages of Amoebozoa are characterized by unusual morphological and ultrastructural features that impede resolving of their position in the phylogenetic tree. Among them is the genus Stygamoeba, not yet reliably placed on the phylogenetic tree even by a phylogenomic analysis. Only two species of Stygamoeba are known at present, and molecular data exists on one species only. Here, we present a description of the mesohaline species Stygamoeba cauta n. sp. isolated from the bottom sediments of Nivå Bay (Baltic Sea, The Sound). This stick-like, flattened amoeba morphologically resembles the previously described species Stygamoeba regulataSmirnov, 1996. However, the molecular analysis based on the 18S rRNA gene sequences and differences in cell behavior and pattern of locomotion provide strong support for establishing a new species.


Assuntos
Amebozoários/classificação , Filogenia , Águas Salinas , Amebozoários/ultraestrutura , Sedimentos Geológicos/parasitologia , Oceanos e Mares , RNA Ribossômico 18S/genética , Especificidade da Espécie
4.
Microb Ecol ; 79(4): 882-897, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31796996

RESUMO

Rain fed granite rock basins are ancient geological landforms of worldwide distribution and structural simplicity. They support habitats that can switch quickly from terrestrial to aquatic along the year. Diversity of animals and plants, and the connexion between communities in different basins have been widely explored in these habitats, but hardly any research has been carried out on microorganisms. The aim of this study is to provide the first insights on the diversity of eukaryotic microbial communities from these environments. Due to the ephemeral nature of these aquatic environments, we predict that the granitic basins should host a high proportion of dormant microeukaryotes. Based on an environmental DNA diversity survey, we reveal diverse communities with representatives of all major eukaryotic taxonomic supergroups, mainly composed of a diverse pool of low abundance OTUs. Basin communities were very distinctive, with alpha and beta diversity patterns non-related to basin size or spatial distance respectively. Dissimilarity between basins was mainly characterised by turnover of OTUs. The strong microbial eukaryotic heterogeneity observed among the basins may be explained by a complex combination of deterministic factors (diverging environment in the basins), spatial constraints, and randomness including founder effects. Most interestingly, communities contain organisms that cannot coexist at the same time because of incompatible metabolic requirements, thus suggesting the existence of a pool of dormant organisms whose activity varies along with the changing environment. These organisms accumulate in the pools, which turns granitic rock into high biodiversity microbial islands whose conservation and study deserve further attention.


Assuntos
Eucariotos/fisiologia , Sedimentos Geológicos/microbiologia , Sedimentos Geológicos/parasitologia , Dióxido de Silício , Eucariotos/isolamento & purificação , Microbiota , Micobioma , Chuva , Espanha
5.
Microb Ecol ; 79(2): 443-458, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31432244

RESUMO

Arcellinida (testate lobose amoebae) are widely used as bio-indicators of lacustrine environmental change. Too much obscuring organic material in a gridded wet Petri dish preparation makes it difficult to observe all specimens present and slows quantification as the organic material has to be carefully worked through with a dissection probe. Chemical deflocculation using soda ash (Na2CO3·H2O), potassium hydroxide (KOH), or sodium hexametaphosphate ((NaPO3)6) has previously been shown to disaggregate and reduce organic content in lake sediments, but to date, no attempt has been made to comparatively evaluate the efficiency of these deflocculants in disaggregating organic content and their impact on Arcellinida analysis in lacustrine sediments. Here, we assess the effectiveness of soda ash, potassium hydroxide, and sodium hexametaphosphate treatments on removing organic content and the impact of those digestions on Arcellinida preservation in 126 sample aliquots subdivided from three sediment samples (YK-20, YK-25, and YK-57) collected from three lakes near Yellowknife, Northwest Territories, Canada. Following treatment, cluster analysis and Bray-Curtis dissimilarity matrix (BCDM) were utilized to determine whether treatments resulted in dissolution-driven changes in Arcellinida assemblage composition. Observed Arcellinida tests in aliquots increased drastically after treatment of organic-rich samples (47.5-452.7% in organic-rich aliquots and by 14.8% in aliquots with less organic matter). The BCDM results revealed that treatment with 5% KOH resulted in the highest reduction in observed organic content without significantly affecting Arcellinida assemblage structure, while soda ash and sodium hexametaphosphate treatments resulted in marginal organic matter reduction and caused severe damage to the arcellinidan tests.


Assuntos
Floculação , Sedimentos Geológicos/parasitologia , Lobosea/isolamento & purificação , Técnicas Microbiológicas/instrumentação , Lagos/parasitologia , Territórios do Noroeste , Parasitologia/métodos
6.
Microbiologyopen ; 8(10): e891, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31218846

RESUMO

Protists are pivotal components of marine ecosystems in terms of their high diversity, but protist communities have been poorly explored in benthic environments. Here, we investigated protist diversity and community assembly in surface sediments in the South China Sea (SCS) at a basin scale. Pyrosequencing of 18S rDNA was performed for a total of six samples taken from the surface seafloor at water depths ranging from 79 to 2,939 m. We found that Cercozoa was the dominant group, accounting for an average of 39.9% and 25.3% of the reads and operational taxonomic units (OTUs), respectively. The Cercozoa taxa were highly diverse, comprising 14 phylogenetic clades, six of which were affiliated with unknown groups belonging to Filosa and Endomyxa. Fungi were also an important group in both read- (18.1% on average) and OTU-derived (9.3% on average) results. Moreover, the turnover patterns of the protist communities were differently explained by species sorting (53.3%), dispersal limitation (33.3%), mass effects (0%), and drift (13.3%). In summary, our findings show that the basin-wide protist communities in the surface sediments of the SCS are primarily dominated by Cercozoa and are mainly assembled by species sorting and dispersal limitation.


Assuntos
Eucariotos/classificação , Eucariotos/genética , Sedimentos Geológicos/microbiologia , Sedimentos Geológicos/parasitologia , Microbiota , Filogenia , China , Análise por Conglomerados , DNA Fúngico/química , DNA Fúngico/genética , DNA de Protozoário/química , DNA de Protozoário/genética , DNA Ribossômico/química , DNA Ribossômico/genética , RNA Ribossômico 18S/genética , Análise de Sequência de DNA
7.
Mar Pollut Bull ; 138: 341-351, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30660283

RESUMO

The benthic foraminiferal diversity index was computed from Beypore estuary sediments. The abundance and diversity of Quinqueloculina lata, Textularia agglutinans, Haplophagmoides canariensis, and Quinqueloculina stelligera were dominated by stress-tolerant taxa such as Ammonia tepida, A.parkinsoniana, Nonion grateloupi, and N. scaphum in the estuary. The small-size foraminifera probably perished in a juvenile stage because of the high temperature and low salinity that prevailed in the ecosystem. The dominance of stress tolerant benthic foraminifera and absence of Elphidium species in the estuary suggest the prevalence of hypoxic (low-oxygen) conditions. The consistent low-diversity index of foraminifera indicates that the ecosystem is moderate to highly stressed ecologically in the Beypore estuary. The application of benthic foraminifera as a bioindicator for assessing the environmental stress in the Beypore estuary is key in monitoring these fragile coastal ecosystems.


Assuntos
Foraminíferos/isolamento & purificação , Sedimentos Geológicos/parasitologia , Biodiversidade , Ecologia , Biomarcadores Ambientais , Estuários , Índia
9.
Korean J Parasitol ; 57(6): 575-580, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31914507

RESUMO

The aim of this study is to determine the species of parasites that affected the inhabitants of the city of Acre on the coast of the eastern Mediterranean during the Ottoman Period. This is the first archaeological study of parasites in the Ottoman Empire. We analysed sediment from a latrine dating to the early 1800s for the presence of helminth eggs and protozoan parasites which caused dysentery. The samples were examined using light microscopy and enzyme-linked immunosorbent assay (ELISA) kits. We found evidence for roundworm (Ascaris lumbricoides), whipworm (Trichuris trichiura), fish tapeworm (Dibothriocephalus sp.), Taenia tapeworm (Taenia sp.), lancet liver fluke (Dicrocoelium dendriticum), and the protozoa Giardia duodenalis and Entamoeba histolytica. The parasite taxa recovered demonstrate the breadth of species present in this coastal city. We consider the effect of Ottoman Period diet, culture, trade and sanitation upon risk of parasitism in this community living 200 years ago.


Assuntos
Sedimentos Geológicos/parasitologia , Helmintos/isolamento & purificação , Enteropatias Parasitárias/história , Enteropatias Parasitárias/parasitologia , Parasitologia/história , Animais , Helmintos/classificação , Helmintos/citologia , História do Século XVIII , Israel , Óvulo/citologia
10.
Korean J Parasitol ; 57(6): 595-599, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31914510

RESUMO

In this study we take a closer look at the diseases that afflicted Japanese police officers who were stationed in a remote mountainous region of Taiwan from 1921 to 1944. Samples were taken from the latrine at the Huabanuo police outpost, and analyzed for the eggs of intestinal parasites, using microscopy and ELISA. The eggs of Eurytrema sp., (possibly E. pancreaticum), whipworm and roundworm were shown to be present. True infection with Eurytrema would indicate that the policemen ate uncooked grasshoppers and crickets infected with the parasite. However, false parasitism might also occur if the policemen ate the uncooked intestines of infected cattle, and the Eurytrema eggs passed through the human intestines. These findings provide an insight into the diet and health of the Japanese colonists in Taiwan nearly a century ago.


Assuntos
Infecções por Cestoides/parasitologia , Infecções por Cestoides/veterinária , Sedimentos Geológicos/parasitologia , Óvulo/citologia , Platelmintos/isolamento & purificação , Animais , Bovinos , Doenças dos Bovinos/história , Doenças dos Bovinos/parasitologia , Infecções por Cestoides/história , História do Século XX , Humanos , Parasitologia/história , Platelmintos/citologia , Taiwan
11.
Korean J Parasitol ; 57(6): 613-619, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31914513

RESUMO

Paleoparasitological analysis was carried on 4 Merovingian skeletons, dated from the late-5th to the late-9th centuries, and recovered in the church of Saint-Martin-au-Val in Chartres (Center region, France). The corpses were buried in stone sarcophagi, which were still sealed at the time of excavation. Parasite marker extraction was conducted on sediment samples taken from the abdominal and pelvic regions, but also on samples taken from under the head and the feet as control samples. Microscopic observation revealed the presence of 3 gastrointestinal parasites, namely the roundworm (Ascaris lumbricoides), the whipworm (Trichuris trichiura) and the fish tapeworm (genus Diphyllobothrium). This analysis contributes to a better knowledge of the health status and the lifestyle of ancient medieval populations during the Merovingian period, for which very few paleoparasitological data were available, up until now. It demonstrates the presence of the fish tapeworm for the first time during this period.


Assuntos
Ascaríase/história , Difilobotríase/história , Tricuríase/história , Animais , Arqueologia/história , Ascaríase/parasitologia , Ascaris lumbricoides/citologia , Ascaris lumbricoides/isolamento & purificação , Cadáver , Difilobotríase/parasitologia , Diphyllobothrium/citologia , Diphyllobothrium/isolamento & purificação , França , Sedimentos Geológicos/parasitologia , História Antiga , Humanos , Óvulo/citologia , Paleopatologia , Parasitologia/história , Tricuríase/parasitologia , Trichuris/citologia , Trichuris/isolamento & purificação
12.
FEMS Microbiol Ecol ; 95(1)2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30452623

RESUMO

Metabarcoding is a method that combines high-throughput DNA sequencing and DNA-based identification. Previously, this method has been successfully used to target spatial variation of eukaryote communities in marine sediments, however, the temporal changes in these communities remain understudied. Here, we follow the temporal changes of the eukaryote communities in Baltic Sea surface sediments collected from two coastal localities during three seasons of two consecutive years. Our study reveals that the structure of the sediment eukaryotic ecosystem was primarily driven by annual and seasonal changes in prevailing environmental conditions, whereas spatial variation was a less significant factor in explaining the variance in eukaryotic communities over time. Therefore, our data suggests that shifts in regional climate regime or large-scale changes in the environment are the overdriving factors in shaping the coastal eukaryotic sediment ecosystems rather than small-scale changes in local environmental conditions or heterogeneity in ecosystem structure. More studies targeting temporal changes are needed to further understand the long-term trends in ecosystem stability and response to climate change. Furthermore, this work contributes to the recent efforts in developing metabarcoding applications for environmental biomonitoring, proving a comprehensive option for traditional monitoring approaches.


Assuntos
Código de Barras de DNA Taxonômico/métodos , Monitoramento Ambiental/métodos , Eucariotos/isolamento & purificação , Sedimentos Geológicos/parasitologia , Mudança Climática , Ecossistema , Eucariotos/classificação , Eucariotos/genética , Eucariotos/metabolismo , Sedimentos Geológicos/química , Sequenciamento de Nucleotídeos em Larga Escala , Estações do Ano
13.
Eur J Protistol ; 67: 46-58, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30453232

RESUMO

The morphology and infraciliature of two haptorian ciliates, Phialina clampi nov. spec. and P. caudata (Kahl, 1933) nov. comb. (original combination: Lacrymaria caudataKahl, 1933), isolated from sandy sediments of an estuary in Yantai, northern China, were investigated using live observations and protargol preparations. Phialina clampi nov. spec. is distinguished from its congeners by the following traits: extended cells about 80-300 × 18-50 µm in vivo; a single oval-shaped macronucleus; caudally located contractile vacuole; two types of extrusomes: type I about 20-35 × 1-4 µm in size, type II 1.5-3.0 × 0.7-1.0 µm in size and attached to somatic cortex; 27-31 somatic kineties. Phialina caudata is characterized as follows: extended cells about 80-170 × 20-45 µm in vivo; body radish-shaped, with a sharp posterior end; a single globular to oval macronucleus and micronucleus; subterminal contractile vacuole; 20-24 somatic kineties. Phylogenetic analyses based on SSU rRNA gene sequences indicate that P. caudata clusters with an unidentified Phialina before grouping with Phialina clampi, which form a basal clade of the family Lacrymariidae.


Assuntos
Cilióforos/classificação , Cilióforos/citologia , Filogenia , China , Cilióforos/genética , Sedimentos Geológicos/parasitologia , RNA Ribossômico/genética , Especificidade da Espécie
14.
Microb Ecol ; 77(2): 277-287, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29951743

RESUMO

Bacterioplankton are both primary producers and primary consumers in aquatic ecosystems, which were commonly investigated to reflect environmental changes, evaluate primary productivity, and assess biogeochemical cycles. However, there is relatively less understanding of their responses to anthropogenic disturbances such as constructions of dams/tunnels/roads that may significantly affect the aquatic ecosystem. To fill such gap, this study focused on the bacterioplankton communities' diversity and turnover during a tunnel construction across an urban lake (Lake Donghu, Wuhan, China), and five batches of samples were collected within 2 months according to the tunnel construction progress. Results indicated that both resources and predator factors contributed significant to the variations of bacterioplankton communities, but the closed area and open areas showed different diversity patterns due to the impacts of tunnel construction. Briefly, the phytoplankton, TN, and TP in water were still significantly correlated with the bacterioplankton composition and diversity like that in normal conditions. Additionally, the organic matter, TN, and NH4-N in sediments also showed clear effects on the bacterioplankton. However, the predator effects on the bacterioplankton in the closed-off construction area mainly derived from large zooplankton (i.e., cladocerans), while small zooplankton such as protozoa and rotifers are only responsible for weak predator effects on the bacterioplankton in the open areas. Further analysis about the ecological driving forces indicated that the bacterioplankton communities' turnover during the tunnel construction was mainly governed by the homogeneous selection due to similar environments within the closed area or the open areas at two different stages. This finding suggests that bacterioplankton communities can quickly adapt to the environmental modifications resulting from tunnel construction activities. This study can also give references to enhance our understanding on bacterioplankton communities' response to ecological and environmental changes due to intensification of construction and urbanization in and around lake ecosystems.


Assuntos
Bactérias/isolamento & purificação , Lagos/microbiologia , Plâncton/isolamento & purificação , Animais , Bactérias/classificação , Bactérias/genética , Biodiversidade , China , Sedimentos Geológicos/microbiologia , Sedimentos Geológicos/parasitologia , Lagos/parasitologia , Filogenia , Plâncton/classificação , Plâncton/genética , Zooplâncton/classificação , Zooplâncton/genética , Zooplâncton/isolamento & purificação
15.
Eur J Protistol ; 66: 115-135, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30261410

RESUMO

Species in the genera Hexasterias and Halodinium have been recorded over the last decades as acritarchs in palynological and/or plankton studies. In paleoenvironmental studies, these resting stages are often interpreted as indicators of freshwater input. The biological affinity of these genera has never been definitely established. Here, a new species, Halodinium verrucatum sp. nov., is described and molecular evidence (single specimen SSU and LSU rDNA sequencing) reveals that both this new species and Hexasterias problematica, collected from sediment samples in the Skagerrak and Baltic Sea, are resting stages of prorodontid ciliates. Additionally, infrared spectroscopic analysis (micro-FTIR) of Hexasterias problematica and Halodinium spp. specimens indicates a carbohydrate-based composition of the cyst wall with evidence for nitrogen-containing functional groups. A similar composition is recorded for tintinnid loricae, which further supports the placement of Hexasterias and Halodinium as ciliate cysts, and the composition is consistent with the heterotrophic nature of ciliates. The morphologically similar species Radiosperma corbiferum has a comparable composition, suggesting a similar ciliate affinity and indicating the utility of micro-FTIR in understanding acritarch affinity. Hexasterias problematica typically occurs in coastal waters from temperate to arctic regions. Halodinium verrucatum sp. nov. is observed in temperate estuarine sediments in the northern hemisphere.


Assuntos
Cilióforos/classificação , Cilióforos/genética , Filogenia , DNA Ribossômico/genética , Sedimentos Geológicos/parasitologia , Encistamento de Parasitas , Especificidade da Espécie
16.
Eur J Protistol ; 66: 9-25, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30086474

RESUMO

Two marine members of the genus Vexillifera Schaeffer, 1926 (Amoebozoa, Dactylopodida) are described. Vexillifera abyssalis n. sp. originates from an abyssal sample of the Western Atlantic 4.5 km deep, which is the first unambiguous record of a deep-sea Vexillifera. The second species, V. kereti n. sp. was isolated from the soft bottom sediments of the White Sea (depth 106 m). An analysis of available data on the genus Vexillifera shows that it comprises many different species, yet they are very unevenly studied. The majority of species have only been described using light microscopy, and their phylogenetic relationships with other amoebae are unclear. However, available small-subunit (SSU) rRNA gene sequences of Vexillifera spp. form a robust, yet very heterogeneous clade in the phylogenetic tree. These species demonstrate a wide range of morphological and ultrastructural characters and originate from diverse habitats, suggesting that Vexillifera may need to be subdivided into several genera in the future. In addition to the described species, we sequenced the COI gene of original CCAP strains of Vexillifera bacillipedes, V. minutissima and Pseudoparamoeba pagei, thereby performing a phylogenetic reconstruction of the Dactylopodida based on a decent taxonomic sampling.


Assuntos
Amebozoários/classificação , Sedimentos Geológicos/parasitologia , Filogenia , Amebozoários/genética , Amebozoários/ultraestrutura , Oceano Atlântico , RNA Ribossômico 18S/genética , Especificidade da Espécie
17.
Sci Rep ; 8(1): 10610, 2018 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-30006509

RESUMO

Foraminifera in sediments exposed to gas-hydrate dissociation are not expected to have cellular adaptations that facilitate inhabitation of chemosynthesis-based ecosystems because, to date, there are no known endemic seep foraminifera. To establish if foraminifera inhabit sediments impacted by gas-hydrate dissociation, we examined the cellular ultrastructure of Melonis barleeanus (Williamson, 1858) from the Vestnesa gas hydrate province (Arctic Ocean, west of Svalbard at ~79 °N; ~1200-m depth; n = 4). From sediments with gas hydrate indicators, living M. barleeanus had unusual pore plugs composed of a thick, fibrous meshwork; mitochondria were concentrated at the cell periphery, under pore plugs. While there was no evidence of endosymbioses with prokaryotes, most M. barleeanus specimens were associated with what appear to be Type I methanotrophic bacteria. One foraminifer had a particularly large bolus of these microbes concentrated near its aperture. This is the first documented instance of bona fide living M. barleeanus in gas-hydrate sediments and first documentation of a foraminifer living in close association with putative methanotrophs. Our observations have implications to paleoclimate records utilizing this foundational foraminiferal species.


Assuntos
Bactérias/isolamento & purificação , Foraminíferos/microbiologia , Sedimentos Geológicos/parasitologia , Simbiose , Regiões Árticas , Bactérias/metabolismo , Foraminíferos/citologia , Foraminíferos/ultraestrutura , Sedimentos Geológicos/microbiologia , Metano/metabolismo , Microscopia Eletrônica de Transmissão , Oceanografia , Paleontologia
18.
Eur J Protistol ; 66: 1-8, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30041072

RESUMO

A new spathidiid ciliate, Apertospathula oktemae n. sp., was isolated from bottom sediments on the eastern shore of Lake Van, Turkey. The living cells are clavate and 45-80 × 17-30 µm in size. This species is characterized by a lasso-shaped circumoral kinety composed of more than 100 dikinetids, 16 meridionally arranged somatic ciliary rows, a three-rowed dorsal brush with 1.5-2.0 µm long bristles, an oblong and curved macronucleus with an ellipsoidal or globular micronucleus, numerous refractive granules in the anterior portion of the cell, and a single posterior contractile vacuole. This new species lives in alkaline brackish water. Apertospathula oktemae differs from congeners by their body shape, number of oral dikinetids, presence of refractive granules, and their habitat. This is the first study to investigate the 18S rRNA gene sequence of a member of the genus Apertospathula. Phylogenetic trees show that Apertospathula oktemae is most closely related to Arcuospathidium sp. There is a discrepancy between the morphological classification system of the spathidiid ciliates and their molecular phylogeny. To overcome this problem, more molecular data, obtained from more taxa from various geographical regions of the world, are needed.


Assuntos
Cilióforos/classificação , Cilióforos/citologia , Lagos/parasitologia , Filogenia , Cilióforos/genética , DNA de Protozoário/genética , Ecossistema , Sedimentos Geológicos/parasitologia , RNA Ribossômico 18S/genética , Águas Salinas , Especificidade da Espécie , Turquia
19.
Eur J Protistol ; 65: 31-41, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29807311

RESUMO

The diversity of marine benthic ciliates is largely known from the intertidal zone. No comparative data are available for the change of ciliate communities from the intertidal to offshore sediments in the Yellow Sea. We investigated the community composition and diversity of benthic ciliates at two intertidal (sandy and silty-sand) stations and eight offshore stations along a latitudinal transect in the Yellow Sea. The ciliate abundance and biomass decreased almost linearly with increasing water depth and distance from the intertidal zone. Diversity indices showed a similar trend. By contrast, the total species richness and taxonomic diversity were much higher in the offshore sediments than in the intertidal area. Among the total of 94 species identified, only 20 species were shared by the two habitats, which were characterized by different dominant ciliate assemblages. Carnivorous ciliates always constituted the primary feeding type in terms of biomass at all offshore stations and the intertidal sandy station, whereas at the intertidal silty-sand station the primary feeding group varied throughout the period of sampling. Multivariate analyses indicates the ciliate communities were significantly different between the two habitats. Bottom water temperature and sediment grain size were the key factors that explained the ciliate community structure.


Assuntos
Biodiversidade , Cilióforos/classificação , Cilióforos/fisiologia , Sedimentos Geológicos/parasitologia , Água do Mar/parasitologia , Ecossistema , Densidade Demográfica
20.
Sci Rep ; 8(1): 7011, 2018 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-29725114

RESUMO

The total dinoflagellate cyst community and the cysts of Cochlodinium polykrikoides in the surface sediments of South Sea (Tongyeong coast), South Korea, were analysed using next-generation sequencing (NGS) and morphological approaches. Dinoflagellate cysts can be highly abundant (111-4,087 cysts g-1 dry weight) and have diverse species composition. A total of 35 taxa of dinoflagellate cysts representing 16 genera, 21 species (including four unconfirmed species), and 14 complex species were identified by NGS analysis. Cysts of Scrippsiella spp (mostly Scrippsiella trochoidea) were the most dominant and Polykrikos schwartzii, Pentapharsodinium dalei, Ensiculifera carinata, and Alexandrium catenella/tamarense were common. Thus, a combination of NGS and morphological analysis is effective for studying the cyst communities present in a given environment. Although C. polykrikoides developed massive blooms during 2013-2014, microscopy revealed low density of their cysts, whereas no cysts were detected by NGS. However, the vegetative C. polykrikoides not appeared during 2015-2017 in spite of the observation of C. polykrikoides cysts. This suggests that the C. polykrikoides blooms were not due to development of their cysts but to other factors such as currents transporting them to a marine environment suitable for their growth.


Assuntos
Biodiversidade , Dinoflagelados/classificação , Dinoflagelados/isolamento & purificação , Sedimentos Geológicos/parasitologia , Animais , Dinoflagelados/citologia , Dinoflagelados/genética , Sequenciamento de Nucleotídeos em Larga Escala , República da Coreia
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