Pub Date : 2017-12-13DOI: 10.4467/16890027AP.17.013.7494
Xin Sheng, Yan Sheng, Yuehua Liu, Junhua Wang
This study aimed to investigate the assembly characteristics of ciliature and cortical microtubules and the localization of tubulins in different depths and regions of the cortex. The hypotrichous ciliates have closely arranged cilia and a highly complex microtubular system. Direct fluorescence and immunofluorescence labeling were used to observe ciliary organelles and cortical microtubular cytoskeleton in Euplotes eurystomus. An immunofluorescence analysis demonstrated that α-tubulin localized to the ventral and dorsal ciliary organelles and their associated microtubules, while γ-tubulin localized to the basal bodies of ciliary organelles, macronuclear membrane, and excretory pore of a contractile vacuole in the interphase. A direct fluorescence analysis showed that the ciliature and cortical microtubules in the deep cortex were more clearly marked by fluorescent taxoid (FLUTAX). Interestingly, α- and γ-tubulins also colocalized to the ringlike ciliary base–associated microtubules of dorsal kineties. The short microtubular bundles between the bases of transverse cirri could be marked by FLUTAX and γ-tubulin rather than α-tubulin, suggesting that tubulins in cortical microtubules in E. eurystomus varied, and the differentiation of cortical microtubules in the hypotrichous ciliate tended to be versatile. Also, during morphogenesis, γ-tubulin also localized to the base of ciliary primordium, where new basal bodies were formed, suggesting that the endocellular position of γ-tubulin in ciliates was related to basal bodies and regulated by the cell cycle. This study might help understand the assembly characteristics and tubulin composition of microtubules in different depths and regions of the cortex in hypotrichous ciliate E. eurystomus.
{"title":"Cortical Localization of α- and γ-Tubulin and the Assembly of Cortical Microtubule Cytoskeleton in Hypotrichous Ciliate Euplotes eurystomus","authors":"Xin Sheng, Yan Sheng, Yuehua Liu, Junhua Wang","doi":"10.4467/16890027AP.17.013.7494","DOIUrl":"https://doi.org/10.4467/16890027AP.17.013.7494","url":null,"abstract":"This study aimed to investigate the assembly characteristics of ciliature and cortical microtubules and the localization of tubulins in different depths and regions of the cortex. The hypotrichous ciliates have closely arranged cilia and a highly complex microtubular system. Direct fluorescence and immunofluorescence labeling were used to observe ciliary organelles and cortical microtubular cytoskeleton in Euplotes eurystomus. An immunofluorescence analysis demonstrated that α-tubulin localized to the ventral and dorsal ciliary organelles and their associated microtubules, while γ-tubulin localized to the basal bodies of ciliary organelles, macronuclear membrane, and excretory pore of a contractile vacuole in the interphase. A direct fluorescence analysis showed that the ciliature and cortical microtubules in the deep cortex were more clearly marked by fluorescent taxoid (FLUTAX). Interestingly, α- and γ-tubulins also colocalized to the ringlike ciliary base–associated microtubules of dorsal kineties. The short microtubular bundles between the bases of transverse cirri could be marked by FLUTAX and γ-tubulin rather than α-tubulin, suggesting that tubulins in cortical microtubules in E. eurystomus varied, and the differentiation of cortical microtubules in the hypotrichous ciliate tended to be versatile. Also, during morphogenesis, γ-tubulin also localized to the base of ciliary primordium, where new basal bodies were formed, suggesting that the endocellular position of γ-tubulin in ciliates was related to basal bodies and regulated by the cell cycle. This study might help understand the assembly characteristics and tubulin composition of microtubules in different depths and regions of the cortex in hypotrichous ciliate E. eurystomus.","PeriodicalId":50883,"journal":{"name":"Acta Protozoologica","volume":"2017 1","pages":"149-160"},"PeriodicalIF":0.5,"publicationDate":"2017-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45887167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-12-13DOI: 10.4467/16890027AP.17.017.7498
I. Koenig, Florence Schwendener, M. Mulot, E. Mitchell
Sphagnum peatlands represent a globally significant pool and sink of carbon but these functions are threatened by ongoing climate change. Testate amoebae are useful bioindicators of hydrological changes, but little experimental work has been done on the impact of water table changes on communities. Using a mesocosm experimental setting that was previously used to assess the impact of drought disturbance on communities and ecosystem processes with three contrasted water table positions: wet (–4 cm), intermediate (–15 cm) and dry (–25 cm), we studied the capacity of testate amoeba communities to recover when the water table was kept at –10 cm for all plots. The overall experiment lasted three years. We assessed the taxonomic and functional trait responses of testate amoeba communities. The selected traits were hypothesised to be correlated to moisture content (response traits: shell size, aperture position) or trophic role (effect traits: mixotrophy, aperture size controlling prey range). During the disturbance phase, the mixotrophic species Hyalosphenia papilio dominated the wet and intermediate plots, while the community shifted to a dominance of “dry indicators” (Corythion dubium, Nebela tincta, Cryptodifflugia oviformis) and corresponding traits (loss of mixotrophy, and dominance of smaller taxa with ventral or ventral-central aperture) in dry plots. During the recovery phase we observed two contrasted trends in the previously wet and intermediate plots: communities remained similar where the Sphagnum carpet remained intact but species and traits indicators of drier conditions increased in plots where it had degraded. In the former dry plots, indicators and traits of wet conditions increased by the end of the experiment. This is one of the first experiment simulating a disturbance and subsequent recovery in ex-situ mesocosms of Sphagnum peatland focusing on the response of testate amoebae community structure as well as functional traits to water table manipulation. The results generally confirmed that testate amoebae respond within a few months to hydrological changes and thus represent useful bioindicators for assessing current and past hydrological changes in Sphagnum peatlands.
{"title":"Response of Sphagnum Testate Amoebae to Drainage, Subsequent Re-wetting and Associated Changes in the Moss Carpet – Results from a Three Year Mesocosm Experiment","authors":"I. Koenig, Florence Schwendener, M. Mulot, E. Mitchell","doi":"10.4467/16890027AP.17.017.7498","DOIUrl":"https://doi.org/10.4467/16890027AP.17.017.7498","url":null,"abstract":"Sphagnum peatlands represent a globally significant pool and sink of carbon but these functions are threatened by ongoing climate change. Testate amoebae are useful bioindicators of hydrological changes, but little experimental work has been done on the impact of water table changes on communities. \u0000Using a mesocosm experimental setting that was previously used to assess the impact of drought disturbance on communities and ecosystem processes with three contrasted water table positions: wet (–4 cm), intermediate (–15 cm) and dry (–25 cm), we studied the capacity of testate amoeba communities to recover when the water table was kept at –10 cm for all plots. The overall experiment lasted three years. We assessed the taxonomic and functional trait responses of testate amoeba communities. The selected traits were hypothesised to be correlated to moisture content (response traits: shell size, aperture position) or trophic role (effect traits: mixotrophy, aperture size controlling prey range). \u0000During the disturbance phase, the mixotrophic species Hyalosphenia papilio dominated the wet and intermediate plots, while the community shifted to a dominance of “dry indicators” (Corythion dubium, Nebela tincta, Cryptodifflugia oviformis) and corresponding traits (loss of mixotrophy, and dominance of smaller taxa with ventral or ventral-central aperture) in dry plots. During the recovery phase we observed two contrasted trends in the previously wet and intermediate plots: communities remained similar where the Sphagnum carpet remained intact but species and traits indicators of drier conditions increased in plots where it had degraded. In the former dry plots, indicators and traits of wet conditions increased by the end of the experiment. \u0000This is one of the first experiment simulating a disturbance and subsequent recovery in ex-situ mesocosms of Sphagnum peatland focusing on the response of testate amoebae community structure as well as functional traits to water table manipulation. The results generally confirmed that testate amoebae respond within a few months to hydrological changes and thus represent useful bioindicators for assessing current and past hydrological changes in Sphagnum peatlands.","PeriodicalId":50883,"journal":{"name":"Acta Protozoologica","volume":"2017 1","pages":"191-210"},"PeriodicalIF":0.5,"publicationDate":"2017-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48870566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-11-24DOI: 10.4467/16890027AP.17.010.7485
M. A. Sousa, B. Santos, C. Carvalhal, M. Steindel
Two KP1(–) strains of Trypanosoma rangeli (SC-58, SC-61) isolated from the wild rodent Phyllomys dasythrix from Santa Catarina (Brazil) were compared with some KP1(+) reference stocks from different Latin America countries, and also with Trypanosoma lewisi. The strains were analyzed by some morphological and biological features, and by biochemical and molecular techniques. The mean total length (TL) of the bloodstream trypomastigotes of T. rangeli varied between 31.3–33.0 μm, and those of T. lewisi (adult forms) was 28.2 μm, values within the variation known for each species. In T. rangeli KP1(+) and T. lewisi, the nucleus was located in the anterior portion of the body, with nuclear indexes (NI) ≥ 1.2, as typically described for both species. Differently, most trypomastigotes of the KP1(–) stocks presented NI ≤ 1.0. Another striking feature of the KP1(–) strains was their very fastidiously growth in axenic cultures when compared with the KP1(+) stocks and T. lewisi. Three isoenzyme loci (MDH, IDH and PGM) clearly distinguished T. rangeli and T. lewisi, and the distinction between the KP1(+) and KP1(–) strains was possible at MDH, PGM and GPI loci. All T. rangeli strains presented the typical 760 bp amplicon derived from their KP2 minicircles. However, the KP3 products of the KP1(+) strains were a single large band (~330bp), whereas those of the KP1(–) had two distinct bands (350 and 300 bp). T. lewisi presented 700 and 400 bp amplicons, as previously reported. The peculiarities of T. rangeli isolates from P. dasythrix corroborate a possible speciation process within this taxon.
{"title":"Peculiarities of Trypanosoma rangeli KP1(-) Strains Isolated from the Wild Rodent Phyllomys dasythrix (Santa Catarina, Brazil): Comparisons with T. rangeli KP1(+) strains and Trypanosoma lewisi (Kinetoplastea, Trypanosomatidae)","authors":"M. A. Sousa, B. Santos, C. Carvalhal, M. Steindel","doi":"10.4467/16890027AP.17.010.7485","DOIUrl":"https://doi.org/10.4467/16890027AP.17.010.7485","url":null,"abstract":"Two KP1(–) strains of Trypanosoma rangeli (SC-58, SC-61) isolated from the wild rodent Phyllomys dasythrix from Santa \u0000Catarina (Brazil) were compared with some KP1(+) reference stocks from different Latin America countries, and also with Trypanosoma \u0000lewisi. The strains were analyzed by some morphological and biological features, and by biochemical and molecular techniques. The mean \u0000total length (TL) of the bloodstream trypomastigotes of T. rangeli varied between 31.3–33.0 μm, and those of T. lewisi (adult forms) was \u000028.2 μm, values within the variation known for each species. In T. rangeli KP1(+) and T. lewisi, the nucleus was located in the anterior portion \u0000of the body, with nuclear indexes (NI) ≥ 1.2, as typically described for both species. Differently, most trypomastigotes of the KP1(–) \u0000stocks presented NI ≤ 1.0. Another striking feature of the KP1(–) strains was their very fastidiously growth in axenic cultures when compared \u0000with the KP1(+) stocks and T. lewisi. Three isoenzyme loci (MDH, IDH and PGM) clearly distinguished T. rangeli and T. lewisi, and \u0000the distinction between the KP1(+) and KP1(–) strains was possible at MDH, PGM and GPI loci. All T. rangeli strains presented the typical \u0000760 bp amplicon derived from their KP2 minicircles. However, the KP3 products of the KP1(+) strains were a single large band (~330bp), \u0000whereas those of the KP1(–) had two distinct bands (350 and 300 bp). T. lewisi presented 700 and 400 bp amplicons, as previously reported. \u0000The peculiarities of T. rangeli isolates from P. dasythrix corroborate a possible speciation process within this taxon.","PeriodicalId":50883,"journal":{"name":"Acta Protozoologica","volume":"2017 1","pages":"119-127"},"PeriodicalIF":0.5,"publicationDate":"2017-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48059392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-11-24DOI: 10.4467/16890027AP.17.006.7481
F. Gómez, K. Kiriakoulakis, E. Lara
We examined the planktonic dinoflagellate Achradina pulchra by light and scanning electron microscopies from the South and North Atlantic oceans. The basket-like skeleton has been interpreted as a thick cell covering or pellicle of organic composition, or as a siliceous endoskeleton. The skeleton of Achradina is known only from fresh material, being absent in preserved samples, sediments or the fossil record. X-ray microanalysis revealed that the endoskeleton of Achradina is composed of celestite (strontium sulfate) with traces of barite (barium sulfate), two minerals that readily dissolve after cell death. To date, Acantharia and polycystine radiolarians (Retaria) were the only known organisms with a skeleton of this composition. We can now add a dinoflagellate to the list of such mineralized skeletons, which influence on the biogeochemical fluxes of strontium and barium in the oceans. Moreover, we provided the first molecular data for a skeleton-bearing dinoflagellate. Molecular phylogeny based on the SSU rRNA gene sequences revealed that Achradina and several environmental clones branched as an independent lineage within the short-branching dinokaryotic dinoflagellates. To date, seven clades of dinokaryotic dinoflagellates are known living as symbionts in the endoplasm of Acantharia and polycystine radiolarians. Because celestite built skeletons were unknown outside radiolarians, we suggested that the ancestors of Achradina acquired the genes implicated in the deposition of strontium and barium from radiolarian hosts though a horizontal gene transfer event between microbial eukaryotes.
{"title":"Achradina pulchra, a Unique Dinoflagellate (Amphilothales, Dinophyceae) with a Radiolarian-like Endoskeleton of Celestite (Strontium Sulfate)","authors":"F. Gómez, K. Kiriakoulakis, E. Lara","doi":"10.4467/16890027AP.17.006.7481","DOIUrl":"https://doi.org/10.4467/16890027AP.17.006.7481","url":null,"abstract":"We examined the planktonic dinoflagellate Achradina pulchra by light and scanning electron microscopies from the South and North Atlantic oceans. The basket-like skeleton has been interpreted as a thick cell covering or pellicle of organic composition, or as a siliceous endoskeleton. The skeleton of Achradina is known only from fresh material, being absent in preserved samples, sediments or the fossil record. X-ray microanalysis revealed that the endoskeleton of Achradina is composed of celestite (strontium sulfate) with traces of barite (barium sulfate), two minerals that readily dissolve after cell death. To date, Acantharia and polycystine radiolarians (Retaria) were the only known organisms with a skeleton of this composition. We can now add a dinoflagellate to the list of such mineralized skeletons, which influence on the biogeochemical fluxes of strontium and barium in the oceans. Moreover, we provided the first molecular data for a skeleton-bearing dinoflagellate. Molecular phylogeny based on the SSU rRNA gene sequences revealed that Achradina and several environmental clones branched as an independent lineage within the short-branching dinokaryotic dinoflagellates. To date, seven clades of dinokaryotic dinoflagellates are known living as symbionts in the endoplasm of Acantharia and polycystine radiolarians. Because celestite built skeletons were unknown outside radiolarians, we suggested that the ancestors of Achradina acquired the genes implicated in the deposition of strontium and barium from radiolarian hosts though a horizontal gene transfer event between microbial eukaryotes.","PeriodicalId":50883,"journal":{"name":"Acta Protozoologica","volume":"2017 1","pages":"71-76"},"PeriodicalIF":0.5,"publicationDate":"2017-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44444565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-11-24DOI: 10.4467/16890027AP.17.011.7486
Hubert Okła, K. Jasik, B. Rozwadowska, Jan Słodki, D. Urbańska-Jasik, M. Grelowski, E. Chmielik, Aleksandra Słodki, Marta Albertyńska, A. Grajoszek
The course of babesiosis in humans is characterized by various intensity levels − from a subclinical level to the severe one − associated with multiple organ failure, which leads to death. The aim of this study was to evaluate the effect of 21-day and 6-month invasion of B. microti on Wistar rats spleen. Histological changes in the rats’ spleen were characterized by swelling of splenic tissue, especially the tissue adjacent to the capsule. In the structure of the white pulp in some rats, high concentrations of lymphocytes occurred. The boundary between the white pulp and red pulp was blurred. In the red pulp structure of rats, a lot of macrophages and extracellular deposits of bilirubin were present. The submicroscopic studies showed that the nuclear matrix was slightly shrunken. In the red pulp fragments of the damaged cells were located in the intercellular spaces. Near these areas, many thrombocytes were visible. The ultrastructural observation also revealed thickened endoplasmic reticulum membranes, local cellular swelling filled with amorphous substance, and digested erythrocytes. B. microti invasion affects the splenic morphology and ultrastructure in rats. The immunological hyperactivity and signs of inflammation indicate an important role of spleen in a fight against parasites.
{"title":"Rat spleen in the course of Babesia microti invasion: histological and submicroscopic studies","authors":"Hubert Okła, K. Jasik, B. Rozwadowska, Jan Słodki, D. Urbańska-Jasik, M. Grelowski, E. Chmielik, Aleksandra Słodki, Marta Albertyńska, A. Grajoszek","doi":"10.4467/16890027AP.17.011.7486","DOIUrl":"https://doi.org/10.4467/16890027AP.17.011.7486","url":null,"abstract":"The course of babesiosis in humans is characterized by various intensity levels − from a subclinical level to the severe one − associated with multiple organ failure, which leads to death. The aim of this study was to evaluate the effect of 21-day and 6-month invasion of B. microti on Wistar rats spleen. Histological changes in the rats’ spleen were characterized by swelling of splenic tissue, especially the tissue adjacent to the capsule. In the structure of the white pulp in some rats, high concentrations of lymphocytes occurred. The boundary between the white pulp and red pulp was blurred. In the red pulp structure of rats, a lot of macrophages and extracellular deposits of bilirubin were present. The submicroscopic studies showed that the nuclear matrix was slightly shrunken. In the red pulp fragments of the damaged cells were located in the intercellular spaces. Near these areas, many thrombocytes were visible. The ultrastructural observation also revealed thickened endoplasmic reticulum membranes, local cellular swelling filled with amorphous substance, and digested erythrocytes. B. microti invasion affects the splenic morphology and ultrastructure in rats. The immunological hyperactivity and signs of inflammation indicate an important role of spleen in a fight against parasites.","PeriodicalId":50883,"journal":{"name":"Acta Protozoologica","volume":"2017 1","pages":"129-137"},"PeriodicalIF":0.5,"publicationDate":"2017-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43101114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-11-24DOI: 10.4467/16890027AP.17.009.7484
A. Kurilov
An improved impregnation method for ciliates has been described with a new formulation for silver proteinate synthesized in situ, that avoids necessary its long-time laboratory synthesis or use of expensive commercial protargol. Compared to conventional techniques, the proposed protocol is more time-saving, reduces the consumption of chemicals and excludes some hazardous ones (e.g. xylene). Structures that are impregnated such as nuclear apparatus, infraciliature, cortical and cytoplasmic microtubules are stained almost identical compared to other protargol methods. Advantages of this method allow us to merge it successfully with ecological quantitative studies of various natural communities of ciliates and provide correct identification of species during such investigations.
{"title":"Improvement of Silver Impregnation Technique Using in Situ Synthesized Protargol","authors":"A. Kurilov","doi":"10.4467/16890027AP.17.009.7484","DOIUrl":"https://doi.org/10.4467/16890027AP.17.009.7484","url":null,"abstract":"An improved impregnation method for ciliates has been described with a new formulation for silver proteinate synthesized in situ, that avoids necessary its long-time laboratory synthesis or use of expensive commercial protargol. Compared to conventional techniques, the proposed protocol is more time-saving, reduces the consumption of chemicals and excludes some hazardous ones (e.g. xylene). Structures that are impregnated such as nuclear apparatus, infraciliature, cortical and cytoplasmic microtubules are stained almost identical compared to other protargol methods. Advantages of this method allow us to merge it successfully with ecological quantitative studies of various natural communities of ciliates and provide correct identification of species during such investigations.","PeriodicalId":50883,"journal":{"name":"Acta Protozoologica","volume":"2017 1","pages":"109-118"},"PeriodicalIF":0.5,"publicationDate":"2017-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46306695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-11-24DOI: 10.4467/16890027AP.17.008.7483
Renu Gupta, J. S. Abraham, S. Somasundaram, R. Toteja, S. Makhija, Hamed A. El‐Serehy
Morphology, morphogenesis and molecular phylogeny of a freshwater oxytrichid ciliate, Aponotohymena isoaustralis n. sp. collected from Sanjay Lake (28°36′51″N, 77°18′14″E), Delhi, India, were studied. The described species is characterized by a flexible body, with body size (in vivo) of about 148 × 46 µm and yellowish green cortical granules. Morphological characters exhibit: undulating membranes in Notohymena–pattern; two macronuclei and absence of micronucleus (amicronucleate); about 36 adoral membranelles; 18 frontoventral-transverse (FVT) cirri; one right and one left marginal row separated posteriorly; 6 dorsal rows; 7 caudal cirri arranged in 2 + 2 + 3 pattern (constant). In the present study, a detailed description of all the developmental stages is also provided. Prominent distinguishing features of the new species are the absence of micronucleus, 7 caudal cirri (constant), yellowish green cortical granules aligned along the margins and irregularly distributed throughout the cell. They may also be randomly concentrated as clusters along the left margin and posterior end of the cell. Molecular phylogeny based on small subunit rDNA sequence data suggests sister relationship of Aponotohymena isoaustralis n. sp. with Notohymena apoaustralis and Aponotohymena australis (Notohymena australis) which cluster in a clade with Paraurostyla weissei and Paraurostyla coronata. Further analysis of nucleotide sequence of SSU rDNA also suggests that A. isoaustralis n. sp. is distinct from the type species A. australis.
{"title":"Taxonomic and Morphogenetic Description of the Freshwater Ciliate Aponotohymena isoaustralis n. sp. (Ciliophora; Oxytrichidae) Isolated from Sanjay Lake, Delhi, India","authors":"Renu Gupta, J. S. Abraham, S. Somasundaram, R. Toteja, S. Makhija, Hamed A. El‐Serehy","doi":"10.4467/16890027AP.17.008.7483","DOIUrl":"https://doi.org/10.4467/16890027AP.17.008.7483","url":null,"abstract":"Morphology, morphogenesis and molecular phylogeny of a freshwater oxytrichid ciliate, Aponotohymena isoaustralis n. sp. collected from Sanjay Lake (28°36′51″N, 77°18′14″E), Delhi, India, were studied. The described species is characterized by a flexible body, with body size (in vivo) of about 148 × 46 µm and yellowish green cortical granules. Morphological characters exhibit: undulating membranes in Notohymena–pattern; two macronuclei and absence of micronucleus (amicronucleate); about 36 adoral membranelles; 18 frontoventral-transverse (FVT) cirri; one right and one left marginal row separated posteriorly; 6 dorsal rows; 7 caudal cirri arranged in 2 + 2 + 3 pattern (constant). In the present study, a detailed description of all the developmental stages is also provided. Prominent distinguishing features of the new species are the absence of micronucleus, 7 caudal cirri (constant), yellowish green cortical granules aligned along the margins and irregularly distributed throughout the cell. They may also be randomly concentrated as clusters along the left margin and posterior end of the cell. Molecular phylogeny based on small subunit rDNA sequence data suggests sister relationship of Aponotohymena isoaustralis n. sp. with Notohymena apoaustralis and Aponotohymena australis (Notohymena australis) which cluster in a clade with Paraurostyla weissei and Paraurostyla coronata. Further analysis of nucleotide sequence of SSU rDNA also suggests that A. isoaustralis n. sp. is distinct from the type species A. australis.","PeriodicalId":50883,"journal":{"name":"Acta Protozoologica","volume":"2017 1","pages":"93-107"},"PeriodicalIF":0.5,"publicationDate":"2017-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48998286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-11-24DOI: 10.4467/16890027AP.17.007.7482
Simona Benčaťová, E. Tirjaková
This is the first detailed study on the morphology of the resting cysts of an oxytrichid ciliate, Rigidohymena quadrinucleata. Resting cysts were investigated using light microscopy, SEM and TEM. The cyst wall is composed of four distinct layers (from inside to outside), namely the metacyst, the endocyst, the mesocyst and the ectocyst with spine-like protuberances. The cysts of R. quadrinucleata belong to the kinetosome-resorbing (KR) type, which is typical for oxytrichids. The processes of encystation and excystation were observed only in the light microscopy. During the encystation process, the trophic cell changes in shape and volume due to dehydration, four macronuclear nodules fuse into a compact mass, the ciliature is resorbed and cyst wall is formed. The most significant feature is surface ornamentation and yellowish color of resting cysts. We also focuse for the first time on excystation process of R. quadrinucleata. We identified two excystation modes: (i) standard and (ii) rare mode. The beginning of both excystation is characterised by the formation of excystation vacuole which helps the excysting cell to break the cyst wall. The specimen regenerates within a thin, flexible membrane. During the standard mode, the cell leaves the resting cyst in the membrane that is resorbed in the environment. During the rare mode, the excystation vacuole and the pressure of the regenerating cell break the transparent membrane that remains in the resting cyst. The results suggest that not only ciliate resting cysts, but also the excystation process is much more variable than what literature data indicate.
{"title":"A Study on Resting Cysts of an Oxytrichid Soil Ciliate, Rigidohymena quadrinucleata (Dragesco and Njine, 1971) Berger, 2011 (Ciliophora, Hypotrichia), including Notes on its Encystation and Excystation Process","authors":"Simona Benčaťová, E. Tirjaková","doi":"10.4467/16890027AP.17.007.7482","DOIUrl":"https://doi.org/10.4467/16890027AP.17.007.7482","url":null,"abstract":"This is the first detailed study on the morphology of the resting cysts of an oxytrichid ciliate, Rigidohymena quadrinucleata. Resting cysts were investigated using light microscopy, SEM and TEM. The cyst wall is composed of four distinct layers (from inside to outside), namely the metacyst, the endocyst, the mesocyst and the ectocyst with spine-like protuberances. The cysts of R. quadrinucleata belong to the kinetosome-resorbing (KR) type, which is typical for oxytrichids. The processes of encystation and excystation were observed only in the light microscopy. During the encystation process, the trophic cell changes in shape and volume due to dehydration, four macronuclear nodules fuse into a compact mass, the ciliature is resorbed and cyst wall is formed. The most significant feature is surface ornamentation and yellowish color of resting cysts. We also focuse for the first time on excystation process of R. quadrinucleata. We identified two excystation modes: (i) standard and (ii) rare mode. The beginning of both excystation is characterised by the formation of excystation vacuole which helps the excysting cell to break the cyst wall. The specimen regenerates within a thin, flexible membrane. During the standard mode, the cell leaves the resting cyst in the membrane that is resorbed in the environment. During the rare mode, the excystation vacuole and the pressure of the regenerating cell break the transparent membrane that remains in the resting cyst. The results suggest that not only ciliate resting cysts, but also the excystation process is much more variable than what literature data indicate.","PeriodicalId":50883,"journal":{"name":"Acta Protozoologica","volume":"2017 1","pages":"77-91"},"PeriodicalIF":0.5,"publicationDate":"2017-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48920663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-09-22DOI: 10.4467/16890027AP.17.001.6965
Noriyuki Kawano, Ryoji Funadani, M. Arikawa, T. Harada, F. Suizu, Kou Matsuoka, T. Matsuoka
We found that vegetative cells of Colpoda cucullus Nag-1 accumulated in shaded areas of a container when grown in the laboratory and then formed resting cysts. The photodispersal (negative photoaccumulation) of C. cucullus was mediated, at least in part, by a difference in forward swimming velocity between the illuminated region and the shaded area of the Petri dish (motion slowed or stopped in the shaded area). When C. cucullus was stimulated by continuous light irradiation, the forward swimming velocity increased and reached a steady state within 10 s. When the light intensity decreased, the forward swimming velocity gradually decreased, and eventually returned to its original level for approximately 1 min. The action spectrum of the photokinetic response (steady-state swimming acceleration driven by continuous light stimulation) implies the involvement of blue light receptors.
{"title":"Photoresponse in the Ciliated Protozoan Colpoda cucullus","authors":"Noriyuki Kawano, Ryoji Funadani, M. Arikawa, T. Harada, F. Suizu, Kou Matsuoka, T. Matsuoka","doi":"10.4467/16890027AP.17.001.6965","DOIUrl":"https://doi.org/10.4467/16890027AP.17.001.6965","url":null,"abstract":"We found that vegetative cells of Colpoda cucullus Nag-1 accumulated in shaded areas of a container when grown in the laboratory and then formed resting cysts. The photodispersal (negative photoaccumulation) of C. cucullus was mediated, at least in part, by a difference in forward swimming velocity between the illuminated region and the shaded area of the Petri dish (motion slowed or stopped in the shaded area). When C. cucullus was stimulated by continuous light irradiation, the forward swimming velocity increased and reached a steady state within 10 s. When the light intensity decreased, the forward swimming velocity gradually decreased, and eventually returned to its original level for approximately 1 min. The action spectrum of the photokinetic response (steady-state swimming acceleration driven by continuous light stimulation) implies the involvement of blue light receptors.","PeriodicalId":50883,"journal":{"name":"Acta Protozoologica","volume":"2017 1","pages":"1-7"},"PeriodicalIF":0.5,"publicationDate":"2017-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46525156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-09-22DOI: 10.4467/16890027AP.17.003.6967
Mingjian Liu, Lifang Li, Zhishuai Qu, Xiaotian Luo, S. Al‐Farraj, Xiaofeng Lin, Xiaozhong Hu
The morphology and phylogeny of two poorly known species, Uronema nigricans (Muller, 1786) Florentin, 1901 and Lembadion lucens (Maskell, 1887) Kahl, 1931, were respectively collected from a eutrophic freshwater river in Shenzhen and an oligotrophic lake in Zhanjiang (both in southern China) and investigated using standard taxonomic methods. The sampled population of Uronema nigricans was characterized by a cell size of 30–40 μm × 12–20 μm in vivo, an elongated elliptical outline with a prominent apical plate, and 13–15 somatic kineties. The sampled population of Lembadion lucens was characterized by a cell size of 45–80 μm × 20–50 μm in vivo, 25–35 somatic kineties, five or six caudal kinetosomes with cilia about 20 μm in length, and a single right-positioned contractile vacuole. The small subunit ribosomal RNA gene (SSU rDNA) of these species was sequenced and compared with those of their congeners to reveal nucleotide differences. The phylogenetic trees showed that the Shenzhen population of Uronema nigricans clusters with two other sequences under the name of “Uronema nigricans” (which are possibly misidentified) and then groups with Uronemita sinensis (Pan et al., 2013) Liu et al., 2016 with full support. Phylogenetic analyses indicated that genus Lembadion is monophyletic with full support provided by both Bayesian inference and maximum likelihood algorithms. Based on analyses of morphological and sequence data, Uronemita sinensis may represent a new genus between Uronema and Uronemita.
分别从深圳的富营养化淡水河和湛江的贫营养化湖泊（均位于中国南方）采集了两个鲜为人知的物种，即黑乌龙线虫（Muller，1786）Florentin，1901和Lembadion lucens（Maskell，1887）Kahl，1931的形态和系统发育，并采用标准分类学方法进行了研究。采样的黑尾蛇种群的特征是体内细胞大小为30-40μm×12-20μm，细长的椭圆形轮廓和突出的根尖板，以及13-15个体细胞动力学。Lembadion lucens的采样群体的特征是体内细胞大小为45-80μm×20-50μm，体细胞动力学为25-35，5或6个尾鳍动体，纤毛长度约为20μm，以及一个右侧收缩液泡。对这些物种的小亚基核糖体RNA基因（SSU rDNA）进行测序，并与它们的同源物进行比较，以揭示核苷酸差异。系统发育树显示，深圳黑尾藻种群与另外两个序列以“黑尾藻”（可能被误认）的名称聚类，然后与中华尾藻（Pan et al.，2013）Liu et al.，2016完全支持。系统发育分析表明，Lembadion属是单系的，贝叶斯推理和最大似然算法都提供了充分的支持。根据形态学和序列数据的分析，中华弯尾虫可能代表了弯尾虫和弯尾虫之间的一个新属。
{"title":"Morphological redescription and SSU rDNA-based phylogeny of two freshwater ciliates, Uronema nigricans and Lembadion lucens (Ciliophora, Oligohymenophorea), with discussion on the taxonomic status of Uronemita sinensis","authors":"Mingjian Liu, Lifang Li, Zhishuai Qu, Xiaotian Luo, S. Al‐Farraj, Xiaofeng Lin, Xiaozhong Hu","doi":"10.4467/16890027AP.17.003.6967","DOIUrl":"https://doi.org/10.4467/16890027AP.17.003.6967","url":null,"abstract":"The morphology and phylogeny of two poorly known species, Uronema nigricans (Muller, 1786) Florentin, 1901 and Lembadion lucens (Maskell, 1887) Kahl, 1931, were respectively collected from a eutrophic freshwater river in Shenzhen and an oligotrophic lake in Zhanjiang (both in southern China) and investigated using standard taxonomic methods. The sampled population of Uronema nigricans was characterized by a cell size of 30–40 μm × 12–20 μm in vivo, an elongated elliptical outline with a prominent apical plate, and 13–15 somatic kineties. The sampled population of Lembadion lucens was characterized by a cell size of 45–80 μm × 20–50 μm in vivo, 25–35 somatic kineties, five or six caudal kinetosomes with cilia about 20 μm in length, and a single right-positioned contractile vacuole. The small subunit ribosomal RNA gene (SSU rDNA) of these species was sequenced and compared with those of their congeners to reveal nucleotide differences. The phylogenetic trees showed that the Shenzhen population of Uronema nigricans clusters with two other sequences under the name of “Uronema nigricans” (which are possibly misidentified) and then groups with Uronemita sinensis (Pan et al., 2013) Liu et al., 2016 with full support. Phylogenetic analyses indicated that genus Lembadion is monophyletic with full support provided by both Bayesian inference and maximum likelihood algorithms. Based on analyses of morphological and sequence data, Uronemita sinensis may represent a new genus between Uronema and Uronemita.","PeriodicalId":50883,"journal":{"name":"Acta Protozoologica","volume":"2017 1","pages":"17-37"},"PeriodicalIF":0.5,"publicationDate":"2017-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48357536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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