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Wyszukujesz frazę "Protists" wg kryterium: Temat


Wyświetlanie 1-13 z 13
Tytuł:
Effects of urbanization on the diversity of testate amoebae (Protist, Rhizopoda) in a stream of the southwestern Amazon basin (Igarapé São Francisco in Acre state, Brazil)
Autorzy:
Gonçalves Araujo, Ronnilda Maria
Cabral, Guilherme Sampaio
Corrêa, Fabiano
Ghidini, André Ricardo
Powiązania:
https://bibliotekanauki.pl/articles/52089922.pdf
Data publikacji:
2023
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
Protists
Plankton
Abundance
Biodiversity
Community
Opis:
We investigated the diversity of testate amoebae in an urban stream located within the Igarapé São Francisco Environmental Protection Area in Acre, northern Brazil, during the dry season, and evaluated the factors mediating the structure of this protist community. We collected 108 water samples for the analysis of the testate amoeba community and the limnological variables at six sampling points on the stream, between July and September 2018. We used a Redundancy Analysis (RDA) to verify the influence of environmental variables on the protist community. We recorded 76 species of testate amoebae from eight families, with most records from the families Difflugiidae, Arcellidae, Centropydae and Netzeliidae. More than half (49) of the species were recorded in Acre for the first time. The abundance of the amoebae of the family Trigonopiridae was regulated by the dissolved oxygen concentrations and the pH, while that of the Netzeliidae, Difflugiidae and Lesquereusidae was influenced by the pH, chloride concentrations, and the depth and transparency of the water. In the case of the family Arcellidae, abundance was determined by the turbidity and transparency of the water and the nitrate concentrations, while that of Centropyxis sp. was associated with the concentrations of thermotolerant coliforms. These findings indicate that, while the São Francisco stream is subject to anthropogenic impacts, it still presents adequate conditions for these organisms in some of its stretches. The abundance of these amoebae was influenced primarily by the productivity of the system, as indicated by the high protist densities recorded in the areas in which primary productivity was highest. These findings support the use of these protists in studies that investigate the most appropriate indicator organisms that respond to anthropogenic impacts and shifts in environmental quality. The results of the present study demonstrated the importance of this aquatic ecosystem for the biodiversity of the study area, and the need to further expand our knowledge on the adaptations and interactions of the aquatic communities of the Amazon region.
Źródło:
Acta Protozoologica; 2023, 62; 25-37
0065-1583
1689-0027
Pojawia się w:
Acta Protozoologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Puzzle-like Cyst Wall in Centrohelid Heliozoans Raphidiophrys heterophryoidea and Raineriophrys erinaceoides
Autorzy:
Zlatogursky, Vasily V.
Powiązania:
https://bibliotekanauki.pl/articles/763423.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
Centrohelids, cysts, heliozoa, protists, scales, ultrastructure
Opis:
The cell body of centrohelid heliozoans is covered with a layer of scales. These scales have species-specific morphology and, since they present in the trophic stage of the cell cycle can be termed “trophic” scales. Several species are known to form cysts; during this process they can produce specific “cyst” scales, different from trophic scales. The present paper describes morphology of cyst scales in two species of centrohelid heliozoans: Raineriophrys erinaceoides and Raphidiophrys heterophryoidea. The latter species has two types of cyst scales: scales of the first type resemble trophic scales in general structure but, their borders are broad, flattened and not enrolled. Scales of the second type are polygonal and connected to each other by special teeth, forming a single layer organized in a jig-saw puzzle-like manner. In Raineriophrys erinaceoides only one type of cyst scale was found. These scales are polygonal and completely different from trophic scales. It is unclear whether these scales form a puzzle-like layer or just overlap each other. Newly excysted individuals keep remnants of cyst scales in their cell coverings and at this stage cyst scales can easily be noted. The morphology of the cyst scales reported here is unlike any other previously reported.
Źródło:
Acta Protozoologica; 2013, 52, 4
1689-0027
Pojawia się w:
Acta Protozoologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heterotrophic Flagellates from Freshwater and Soil Habitats in Subtropical China (Wuhan Area, Hubei Province)
Autorzy:
Tikhonenkov, Denis V.
Mylnikov, Alexander P.
Gong, Ying Chun
Feng, Wei Song
Mazei, Yuri
Powiązania:
https://bibliotekanauki.pl/articles/763607.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
Heterotrophic flagellates, China, subtropics, soil, freshwater, protists
Opis:
We studied the diversity of heterotrophic flagellates from the sandy sediments of the Yangtze River, sandy and silty sediments of Donghu Lake, soil, moss and litter from the Luojiashan and Moshan hills as well as litter from the floodplain near Donghu Lake in April 2010. Sixty-seven heterotrophic flagellate species were identified by means of phase and interference contrast light microscopy and transmission electron microscopy. The majority of the observed flagellates were bacterivorous. Local species richness of river sediment communities was significantly lower than that of lake sediments and terrestrial habitats. The communities from the terrestrial habitats were more heterogeneous than those from freshwater sediments. Common species for the aquatic habitats were Rhynchomonas nasuta, Paraphysomonas sp., Neobodo designis, N. curvifilis, Bodo saltans and Spumella spp. In the soils only Spumella spp. was found in the majority of samples. Most characteristic taxa for the lake sediments were Helkesimastix faecicola, Petalomonas minuta, P. pusilla, Diphylleia rotans, Amastigomonas caudata. Amoeboflagellates such as Cercomonas angustus, C. granulifera, Paracercomonas crassicauda were specific for the terrestrial habitats. There were no specific taxa in the river sediments. The majority of the heterotrophic flagellates identified in this survey have been noted in China earlier. They are common (and usually predominant) for other regions in both freshwater and soil habitats.
Źródło:
Acta Protozoologica; 2012, 51, 1
1689-0027
Pojawia się w:
Acta Protozoologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Growth Rate Modulation Enables Coexistence in a Competitive Exclusion Scenario Between Microbial Eukaryotes
Autorzy:
Ribeiro, Giulia Magri
Prado, Paulo Inácio
Coutinho, Renato Mendes
Rillo, Marina Costa
Pereira Junior, Samuel
Porfírio-Sousa, Alfredo L.
Lahr, Daniel J. G.
Powiązania:
https://bibliotekanauki.pl/articles/52229629.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
competition
protists
testate-amoeba
experimental ecology
coexistence
microcosm
Opis:
Coexistence usually are exceeding the explicable rate by competitive exclusion principle. Since the pioneer Gause, many studies have used protist microcosm systems to study competitive exclusion. We explored a two-species system with the testate-amoebae: (Arcella intermedia and Pyxidicula operculata), where competitive exclusion is expected to occur. We determined their growth curves individually and under competitive interaction. We used a state-space model to represent system dynamics and calculated posterior population sizes simulating competition dynamics. Contrarily to our expectation, Arcella and Pyxidicula showed similar growth rates (1.37 and 1.46 days–1 respectively) and only different carrying capacity (1,997 and 25,108 cells cm–2 respectively). The maximum number of cells of both species when growing in competition was much lower if compared to the monospecific cultures (in average, 73% and 80% less for Arcella and Pyxidicula respectively). However, our competition experiments always resulted in coexistence. According to the models, the drop in growth rates and stochasticity mainly explains our coexistence results. We propose that a context of ephemeral resources can explain these results. Additionally, we propose generating factors of stochasticity as intraspecific variation, small population effects, toxicity of waste products and influence of the bacterial community.
Źródło:
Acta Protozoologica; 2019, 58, 4; 217-233
0065-1583
1689-0027
Pojawia się w:
Acta Protozoologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Particle-associated Planktonic Naked Amoebae in the Hudson Estuary: Size-fraction Related Densities, Cell Sizes and Estimated Carbon Content
Autorzy:
Anderson, O. Roger
Powiązania:
https://bibliotekanauki.pl/articles/763678.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
Aquatic food webs, carbon budgets, microbial ecology, micro-habitats, protists
Opis:
Naked amoeba densities, sizes, biodiversity and carbon content were examined in relation to two particle size fractions (< 200 μm and > 200 μm) of suspended matter in the water column of the Hudson Estuary at a near-shore location south of the Tappan Zee, Palisades, New York. The densities varied markedly among the two particle fractions, and therefore the mean densities were not significantly different between the larger and smaller particle fractions. In contrast, the mean sizes and mean carbon content were statistically greater on larger size suspended particles compared to smaller size particles. There was a broader size range of amoebae on the larger particles, including very large Cochliopodium, Vannella, Mayorella, and Hartmannella species suggesting a larger biodiversity, also indicated by a larger diversity coefficient for the > 200-μm-particle fraction compared to the < 200-μm-particle fraction, 4.51 and 4.18, respectively. In conclusion, the size of suspended particulates in the water column of near-shore, estuarine habitats may have a significant influence on the composition of naked amoebae communities and their ecological roles, especially the organization of particle-associated microbial food webs.
Źródło:
Acta Protozoologica; 2011, 50, 1
1689-0027
Pojawia się w:
Acta Protozoologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Centrohelid Heliozoans (Centroplasthelida Febvre-Chevalier et Febvre, 1984) from Different Types of Freshwater Bodies in the Middle Russian Forest-steppe
Autorzy:
Prokina, Kristina I.
Zagumyonnyi, Dmitry G.
Tikhonenkov, Denis V.
Powiązania:
https://bibliotekanauki.pl/articles/52258270.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
centrohelids
heliozoans
protists
morphology
electron microscopy
sphagnum bog
lake
river
Opis:
Species diversity of centrohelid heliozoans in different types of freshwater bodies (forest lakes, floodplain lakes, sphagnum bogs, and river) in the Middle Russian forest-steppe was studied. The morphology of cell coverings (scales and spicules) were observed using scanning and transmission electron microscopy. A total of 20 species of  centrohelid heliozoans from five families (Acanthocystidae, Pterocystidae, Raphidiophryidae, Raphidocystidae, and Choanocystidae) and six genera (Acanthocystis, Raineriophrys, Pterocystis, Raphidiophrys, Raphidocystis, and Choanocystis) as well as unidentified Centrohelea species and a Heterophrys-like organism were found. Morphological descriptions and electron micrographs are provided. The most common species were Acanthocystis nichollsi, Raphidiophrys capitata, and a Heterophrys-like organism. The highest species diversity was observed in terrace forest lakes, whereas the lowest was seen in sphagnum bogs. Four species (Acanthocystis costata, A. elenazhivotovae, A. mikrjukovii, and A. spinosa) were found for the first time since their original description. Three species (Acanthocystis spinosa, Raphidiophrys capitata, and Pterocystis pulchra) are new records for Russia. The distribution of the observed morphospecies confirms the cosmopolitanism of many centrohelids and highlights the importance of the type of water body and microbiotope in forming the species composition. The obtained data on the morphology of studied scales supplements our knowledge of the intraspecific variability of centrohelid heliozoans.
Źródło:
Acta Protozoologica; 2018, 57, 4; 243-266
0065-1583
1689-0027
Pojawia się w:
Acta Protozoologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Abundances of Naked Amoebae and Macroflagellates in Central New York Lakes: Possible Effects by Zebra Mussels
Autorzy:
Bischoff, Paul J.
Horvath, Thomas G.
Powiązania:
https://bibliotekanauki.pl/articles/763680.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
Flagellates, invasive species, naked amoebae, nearshore zone, protists, zebra mussels
Opis:
Zebra mussels (Dreissena polymorpha) are bivalve mollusks that have invaded and altered the ecology of many North American lakes and rivers. To identify possible ecological effects of zebra mussels on naked amoebae, this study compared abundances of sediment and water column naked amoebae in shallow water zones of four lakes with and four lakes without zebra mussels. Additional data was collected on the density of macroflagellates. Although no statistically significant difference in naked amoebae density was found, higher ratios of sediment to water column naked amoebae abundances in zebra mussel lakes were observed due to increased naked amoebae abundances in the sediments. However, we did not observe a concomitant decrease in water column naked amoebae abundances. Flagellate abundances revealed no significant differences between the two lake types. Taken together, the data show that naked amoebae and flagellates thrive in shallow water zones of zebra mussel lakes and that the filter feeding activities of zebra mussels and reported reduced water column protists abundances may be offset by the flocculation of protists from the rich zebra mussel colonies.
Źródło:
Acta Protozoologica; 2011, 50, 1
1689-0027
Pojawia się w:
Acta Protozoologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Challenges of Incorporating Realistic Simulations of Marine Protists in Biogeochemically Based Mathematical Models
Autorzy:
Davidson, Keith
Powiązania:
https://bibliotekanauki.pl/articles/763796.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
Mathematical modelling, protists, NPZD models, PFT models, trait based models, IBM models
Opis:
Protists are key components of marine microbial communities and hence of the biogeochemical mathematical models that are used to study the interaction between organisms, and the associated cycling of carbon and other nutrients. With increased computing power, models of microbial communities have markedly increased in complexity in the last 20 years, from relatively simple single nutrient currency, nutrient-phytoplankton-zooplankton-detritus (NPZD) models to plankton functional type (PFT) or trait based models of multiple organisms, or individual based models (IBMs) of specific organisms. However, our recognition, if not parameterisation, of the physiological processes that underpin both autotrophic and heterotrophic protist nutrition and growth arguably have increased faster than our modelling capability, generating a wealth of new modelling challenges. This paper therefore reviews historical development, current capability, and the future directions and challenges in protist based mathematical modelling.
Źródło:
Acta Protozoologica; 2014, 53, 1
1689-0027
Pojawia się w:
Acta Protozoologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recent Advances in Application of Transcriptomics: Research on Heterotrophic and Autotrophic Protists
Autorzy:
Anderson, O. Roger
Powiązania:
https://bibliotekanauki.pl/articles/52001052.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
Algae
autotrophy
ecology
ecosystems
functional groups
genomics
heterotrophic protists
metabolism
parasitism
physiology
Opis:
The application of molecular phylogenetics to research on protists has substantially transformed our understanding of their evolution and systematics. More recently, advances in molecular technology, including high throughput sequencing, has opened new avenues for genomic analyses that elucidate major aspects of protistan biology across all levels of biological organization from cellular to ecosystems. This is a review of recent advances (particularly in the last two decades) of transcriptomic research on heterotrophic and autotrophic protists within three major topics: (i) Physiology and metabolism, (ii) Development and life cycles, and (iii) Environmental and ecological studies. Emphasis is placed on selection of representative research that highlights findings across diverse taxonomic groups within each of the three topics. Examples are drawn from parasitic as well as free-living taxa to provide a broad overview of some of the research strategies, and major findings, that have emerged from application of transcriptomics and related techniques in advancing our understanding of protistan biology.
Źródło:
Acta Protozoologica; 2022, 61; 47-75
0065-1583
1689-0027
Pojawia się w:
Acta Protozoologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Testate Amoebae in Karst Caves of the Dinaric Arc (South-Eastern Europe) with a Description of Centropyxis bipilata sp. nov.
Autorzy:
Baković, Najla
Siemensma, Ferry J.
Baković, Robert
Rubinić, Josip
Powiązania:
https://bibliotekanauki.pl/articles/52089991.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
cave testate amoebae
karst cave connectivity
cave protists
phototrophic organisms in caves
aphotic habitats
Opis:
Karst freshwater caves are subterranean habitats characterized by the constant absence of light and relatively small variations of temperature and air humidity. They are mostly food deprived environments, with the exception if large bat colonies are present or if they are intensively supplied with organic matter by sinking rivers. Even though these habitats are often described as harsh, they have enabled the evolution of highly specialized and often endemic animals. The cave eukaryotic micro-organisms, on the other hand, are scarcely researched. The results of research of testate amoebae in the caves of the Dinaric arc detected 23 species, 12 of which were first found in caves. Also, a description of Centropyxis bipilata sp. nov. is presented. This species is clearly distinguished from other described species based on shell size, the presence of two struts and the usually dark ring around the aperture. Testate amoebae were registered on aquatic and terrestrial cave sediments and transitional habitats (like hygropetric and wet walls). The most frequent species within the samples were: Trinema lineare, Cryptodifflugia oviformis and Centropyxis bipilata sp. nov. Maximum diversity of testate amoebae was registered in Ponor Kovači with twenty species. In 24.4 % of the investigated samples  microphototrophs were found, implying good surface-subsurface connectivity that could also affect testate amoebae diversity. This research showed that caves are underestimated habitats that can provide us with new data about the testate amoebae biogeography and diversity.
Źródło:
Acta Protozoologica; 2019, 58, 4; 201-215
0065-1583
1689-0027
Pojawia się w:
Acta Protozoologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changing Views of Arctic Protists (Marine Microbial Eukaryotes) in a Changing Arctic
Autorzy:
Lovejoy, Connie
Powiązania:
https://bibliotekanauki.pl/articles/763549.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
Polar, marine microbial eukaryotes, protists, water masses, climate change, Subsurface Chlorophyll Maxima, High Throughput Sequencing
Opis:
Advances in sequencing technology and the environmental genomic approaches have brought attention to the vastness of protist biodiversity. While over much of the world’s oceans the species and phylotypes making up this diversity are assumed to be something previously hidden and now revealed, the recent rapid changes in the Arctic mean that such assumptions may be a simplification. Historical morphological species data can be used to validate new records provided that more of these species are identified using standard molecular markers. Environmental surveys can also go further by identifying species over regions, seasons and depths. High throughput sequencing and bioinformatics tools provide a means of monitoring and eventually predicting the consequences of change. We give an example of how microbial eukaryote communities differ over pan-arctic scales, emphasizing the need for additional sampling and the need for caution in extrapolating the results of one region to the entire Arctic.
Źródło:
Acta Protozoologica; 2014, 53, 1
1689-0027
Pojawia się w:
Acta Protozoologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Description of Paramoeba atlantica n. sp. (Amoebozoa, Dactylopodida) – a Marine Amoeba from the Eastern Atlantic, with Emendation of the Dactylopodid Families
Autorzy:
Kudryavtsev, Alexander
Pawlowski, Jan
Hausmann, Klaus
Powiązania:
https://bibliotekanauki.pl/articles/763698.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
Amoebozoa, Dactylopodida, deep-sea protists, Paramoeba atlantica n. sp., phylogeny, SSU rDNA, taxonomy, ultrastructure
Opis:
A strain of marine amoeba has been isolated and studied from the bottom sediments of the Great Meteor Seamount (Atlantic Ocean, 29°36.29′N; 28°59.12′W; 267.4 m deep). This amoeba has a typical dactylopodiid morphotype, a coat of delicate, boat-shaped scales, and a Perkinsela-like organism (PLO), an obligatory, deeply-specialized kinetoplastid symbiont near the nucleus. These characters allow us to include this species into the genus Paramoeba. However, it differs from its only described species, P. eilhardi, in the structure of scales. P. atlantica n. sp. is established therefore to accommodate the studied strain. SSU rRNA gene sequence analysis suggests that P. atlantica belongs to the Dactylopodida, and is sister to a monophyletic clade of P. eilhardi and all Neoparamoeba spp., branching separately from P. eilhardi. Therefore, the genera Paramoeba and Neoparamoeba, currently defined based on the cell surface ultrastructure, might be paraphyletic and probably should be synonymized, as further evidence is accumulated. Based on the data available we emend the families Vexilliferidae and Paramoebidae to make them more consistent with the current phylogenetic schemes.
Źródło:
Acta Protozoologica; 2011, 50, 3
1689-0027
Pojawia się w:
Acta Protozoologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two New Species of Centrohelid Heliozoans: Acanthocystis costata sp. nov. and Choanocystis symna sp. nov.
Autorzy:
Zlatogursky, Vasily V.
Powiązania:
https://bibliotekanauki.pl/articles/763738.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
Centrohelids, Heliozoa, protists, systematics, ultrastructure, external skeleton, Acanthocystis costata sp. nov., Choanocystis symna sp. nov.
Opis:
Two new species of centrohelid heliozoans Acanthocystis costata and Choanocystis symna from a freshwater lake on Valamo Island and a freshwater pool in St. Petersburg (North-Western Russia) were studied with light and electron microscopy. Sequences of 18S rDNA were obtained for both species. Choanocystis symna has dumbbell-shaped plate scales (4.4–5.0 × 1.62–1.90 µm) and spine scales (3.9–6.7 µm) bearing from 3 to 5 (usually four) short teeth on the distal end. Acanthocystis costata has oval plate scales (1.3–3.7 × 0.9–1.9 µm), bearing numerous granules as well as radial slits and spine scales (2.1–9.5 µm) with 4–6 teeth on the distal end. Acanthocystis costata and Acanthocystis nichollsi are similar in having slit-bearing plate scales and group together on the 18S rDNA tree. The presence of large particles of unknown nature was observed in food vacuoles of Acanthocystis costata.
Źródło:
Acta Protozoologica; 2014, 53, 4
1689-0027
Pojawia się w:
Acta Protozoologica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-13 z 13

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