ln order to discuss the optimum seedling density of Toona ciliate, different seedling densities were studied. The results showed that seeding height and basal diameter decreased and quality of the seedlings declined w...ln order to discuss the optimum seedling density of Toona ciliate, different seedling densities were studied. The results showed that seeding height and basal diameter decreased and quality of the seedlings declined with the increase of seedling density. The reasonable density of seedlings is key to cultivate high-quality seedlings and achieve the best seedling efficiency. The optimum density was 30 plants/m2 for the first class seedlings of biennial seedlings, and the optimum density of l and ll seedlings for production afforestation was 40 plants/m2.展开更多
This study explored the molecular diversity and biogeography of benthic ciliates in Chinese marginal seas, the Bohai Sea(BHS), North Yellow Sea(NYS) and South Yellow Sea(SYS). From a previous 18S rRNA gene pyrosequenc...This study explored the molecular diversity and biogeography of benthic ciliates in Chinese marginal seas, the Bohai Sea(BHS), North Yellow Sea(NYS) and South Yellow Sea(SYS). From a previous 18S rRNA gene pyrosequencing dataset of the benthic microeukaryotes, we retrieved the sequences affiliated with phylum Ciliophora and analyzed alpha and beta diversities of ciliate communities. We found that BHS had the highest ciliate operational taxonomic unit(OTU) richness than NYS and SYS, whereas the richness was not significantly different between summer and winter. Among all the measured environmental variables, water depth showed consistently the strongest correlations with alpha diversities. Overall, the class Spirotrichea(mostly Choreotrichia and unassigned lineages within the class) dominated the communities in terms of both relative proportion of sequences(77.0%) and OTU richness(66.5%). OTU-level ciliate community structure was significant different among the three basins, but not between the seasons. Structurally, significant differences in relative proportion among the basins were detected for the class Litostomatea, but not for other classes. Partial Mantel tests demonstrated that water depth difference was more important than geographic and environment distances in shaping the community structure of benthic ciliates in the studied area. About 60% OTUs were not assigned at a class or order level and at least 45% OTUs shared a sequence similarity no more than 97% with the described species, indicating a great potential for ciliate species discovery in the offshore sediments. Compared with previous morphology-based surveys, the spatial pattern of ciliate diversity(decreasing from NYS to SYS) is also identified in the present study. Nevertheless, structurally, the dominant class appeared to be Spirotrichea in the sequencing dataset, which differs from previous morphology-based results(dominance of classes Prostomatea and Karyorelictea in biomass). The potential causes for the discrepancies between molecular and morphological findings are also discussed.展开更多
The tolerance to ammonia and nitrites in freshwater ciliate Paramecium bursaria was measured in a conventional open system. The ciliate was exposed to different concentrations of ammonia and nitrites for 2h and 12h in...The tolerance to ammonia and nitrites in freshwater ciliate Paramecium bursaria was measured in a conventional open system. The ciliate was exposed to different concentrations of ammonia and nitrites for 2h and 12h in order to determine the lethal concentrations. Linear regression analysis revealed that the 2h-LC50 value for ammonia was 95.94 mg/L and for nitrite 27.35 mg/L using probit scale method (with 95% confidence intervals). There was a linear correlation between the mortality probit scale and logarithmic concentration of ammonia which fit by a regression equation y=7.32x–9.51 (R2=0.98; y, mortality probit scale; x, logarithmic concentration of ammonia), by which 2 h–LC50 value for ammonia was found to be 95.50 mg/L. A linear correla- tion between mortality probit scales and logarithmic concentration of nitrite is also followed the regression equa- tion y=2.86x+0.89 (R2=0.95; y, mortality probit scale; x, logarithmic concentration of nitrite). The regression analysis of toxicity curves showed that the linear correlation between exposed time of ammonia-N LC50 value and ammonia-N LC50 value followed the regression equation y=2 862.85e-0.08x (R2=0.95; y, duration of exposure to LC50 value; x, LC50 value), and that between exposed time of nitrite-N LC50 value and nitrite-N LC50 value followed the regression equation y = 127.15e-0.13x (R2=0.91; y, exposed time of LC50 value; x, LC50 value). The results demonstrate that the tolerance to ammonia in P. bursaria is considerably higher than that of the larvae or juveniles of some metozoa, e.g. cultured prawns and oysters. In addition, ciliates, as bacterial predators, are likely to play a positive role in maintaining and improving water quality in aquatic environments with high-level ammonium, such as sewage treatment systems.展开更多
The annual bloom of the green macroalgal Ulva prolifera from May through July since 2008 and another of giant jellyfi sh Nemopilema nomurai from June through September have been frequent events in the Yellow Sea. Howe...The annual bloom of the green macroalgal Ulva prolifera from May through July since 2008 and another of giant jellyfi sh Nemopilema nomurai from June through September have been frequent events in the Yellow Sea. However, the patterns of benthic ciliate communities during and after the blooms are still not known. In combination with analyses of benthic environmental factors, we investigated the distribution and community composition of benthic ciliates in the Yellow Sea in July and November 2011. In July, ciliates had high standing crops and diversity in the northern Yellow Sea, and in the inshore area off the southern Shandong Peninsula, where large numbers of green macroalgae accumulated. In November, the abundance, biomass and diversity of ciliates were high in the sea areas off the Shandong Peninsula and Changjiang estuary, where a large quantity of jellyfi sh occurred in August. Neither the abundance nor the biomass had signifi cant diff erence between seasons, or between diff erent compartments of the Yellow Sea. The species number, and both Margalef and Shannon-Wiener indices of ciliates were all signifi cantly higher in November than in July. In both seasons, prostomateans and karyorelicteans consistently constituted the fi rst and second most important ciliate groups in biomass; and carnivorous ciliates constituted the primary feeding type in terms of biomass as well as species richness, followed by bacterivores, algivores and omnivores. Compared with that in June 2007 when no macroalgae occurred, the percentage of small-sized bacterivores(e.g. Metacystis spp., Euplotes spp. and scuticociliates) increased in July 2011. The proportion of carnivorous ciliates increased in November, and this increased dominance of carnivorous ciliates may be a response to the increase in predominance of heterotrophic nanofl agellates, which might in turn be ascribed to an eff ect of green macroalgal and giant jellyfi sh blooms in the Yellow Sea.展开更多
Ciliates play a curial role in energy transfer from pico- and nano-phytoplankton to mesozooplankton in marine ecosystems. In order to visualize their geographical distributions from the Java Sea to the South China Sea...Ciliates play a curial role in energy transfer from pico- and nano-phytoplankton to mesozooplankton in marine ecosystems. In order to visualize their geographical distributions from the Java Sea to the South China Sea （6~S to 20~N）, the authors investigated the ciliate abundance and species composition in sur- face waters during May 18 to 27 of 2010. The ciliate abundance decreased latitudinally from 3 080 ind./L （~6~S） to 40 ind./L （-~3~N）, and then increased to 1 180 ind./L （-~ 16~N） at the end of the survey. A total of 22 ciliates belonging to 15 genera were identified with the tintinnids accounted for 50% （11 species）; and the species number showed a same spatial change as the ciliate abundance. Moreover, the Strombidium oc- cupied over 50% of total ciliate abundance in most stations and Mesodiniurn and Tintinnopsis contributed to about 18.7% and 11.4%, respectively. In particular, our results indicate that the geographical changes in ciliate abundance were positively regulated by larger nano- and micro-phytoplankton biomass, rather than smaller pico-phytoplankton in the investigated waters.展开更多
We assessed the potential of marine ciliate community as an indicator to coastal water quality using water samples collected from four stations in thc Yellow Sea in the summer 2000. The four stations were characterize...We assessed the potential of marine ciliate community as an indicator to coastal water quality using water samples collected from four stations in thc Yellow Sea in the summer 2000. The four stations were characterized by different levels of pollution. The ciliate communities consisted primarily of tintinnids and aloricate ciliates that were 〈30 um. A total of 78 species were classified： 55 species at Station 2, 51 species each at Stations l and 4, and 47 species at Station 3. The mean number of species at each site was 29.2±2.0 （Station 1）, 28.5±2.9 （Station 2）, 27.8±1.7 （Station 3）, and 24.5±2.3 （Station 4）. The abundance was highly variable： 19 331±11 187 ind./L at Station 1, 7 960±5 639 ind./L at Station 2, 29 015±12 999 ind./L at Station 3, and 8 190±4 658 ind./L at Station 4. Our results suggest that neither the simple chemical analysis （e.g. chemical oxygen demand, dissolved inorganic nitrogen, and phosphate） nor the eutrophication/pollution index adequately described the water quality at the four stations. The same was true of the number of species and their abundance, both of which had no correlation with the chemical indices. In contrast, Margalef＇s diversity index values （3.12 at Station 2, 2.89 at Station 1, and 2.64 at Stations 3 and 4） generally discriminated the water quality status of the four stations. The difference in water quality among the stations was strongly supported by the pattern of species richness （i.e. the total number of species） of ciliates at each station. Our evaluation was consistent with the results of long-term water quality monitoring at the four stations. With increasing eutrophication, we observed also a compositional and functional shift in the ciliate assemblages from algivorous oligotrich/choreotrich to nonselective-omnivorous gymnostomatids to bacterivorous-detrivorous scuticociliatids. Thus, eiliates may be used to indicate the coastal water quality status of a given site.展开更多
Ciliates are important components in planktonic food webs,but our understanding of their community structures in different oceanic water masses is limited.We report pelagic ciliate community characteristics in three s...Ciliates are important components in planktonic food webs,but our understanding of their community structures in different oceanic water masses is limited.We report pelagic ciliate community characteristics in three seas:the tropical West Pacific,the Bering Sea and the Arctic Ocean.Planktonic ciliate abundance had"bimodal-peak","surface-peak"and"DCM(deep chlorophyll a maximum layer)-peak"vertical distribution patterns in the tropical West Pacific,the Bering Sea and the Arctic Ocean,respectively.The abundance proportion of tintinnid to total ciliate in the Bering Sea(42.6%)was higher than both the tropical West Pacific(7.8%)and the Arctic Ocean(2.0%).The abundance proportion of small aloricate ciliates(10–20μm size-fraction)in the tropical West Pacific was highest in these three seas.The Arctic Ocean had higher abundance proportion of tintinnids in larger LOD(lorica oral diameter)size-class.Proportion of redundant species increased from the Arctic Ocean to the tropical West Pacific.Our result provided useful data to further understand ecology roles of planktonic ciliates in different marine habitats.展开更多
Ciliates are very important components in most marine ecosystem. They are trophic link between the microbial food web and grazing food chain. In this study, ciliates were collected from 11 sites in the southern South ...Ciliates are very important components in most marine ecosystem. They are trophic link between the microbial food web and grazing food chain. In this study, ciliates were collected from 11 sites in the southern South China Sea （SCS） during August 25 to September 28, 2011. Their composition and distribution at the surface and 75m deep depth of the ocean were studied. A total of 30 species belonging to 22 genera were identified, and 22 species of 15 genera were Tintinnids. Eutintinnusfraknoii and E. stramentus were the most common species. The other dominants were strombidiids ciliates including Strombidium conicum and S. globosaneum, which were followed by the tide form, Mesodinium pulex. Ciliates abundance ranged from 46 indL-1 to 368 indL-1 in the open sites, 46-368indL-1 at surface and 73-198indL-1 at 75m deep layer. In the Yongshu reef, ciliates abundance ranged from 167indL-1 to 365 ind L-1 in the water colunm, similar to that in Sanya coral reef waters. Ciliates composition showed obvious difference between surface and 75m deep layer at station S2 （P〈0.05）, while no similar result was observed at other sites. At 75m deep layer, salinity was negatively related to mixed layer depth （P〈 0.05）, but positively to chlorophyll a concentration （P〈 0.05）, indicating that the change of vertical mixing in water column influenced vertical distribution of ciliates in the southern SCS.展开更多
To study population dynamics of marine ciliates in different artificial seawaters （ASW）, the population growth dynamics of a common marine ciliate Euplotes vannus were investigated using beef extract media and rice ...To study population dynamics of marine ciliates in different artificial seawaters （ASW）, the population growth dynamics of a common marine ciliate Euplotes vannus were investigated using beef extract media and rice media for five types of ASW and natural seawater （NSW）. The results show that： （1） the population growth rate was in the order of NSW〉Flack ASW〉Nakamula ASW〉Schmadz ASW〉Oshima ASW〉Subow ASW and was considerably higher in rice media than in beef extract media （apart from Subow ASW）; （2） the maximum density of E. vannus in stationary phase in each treatment was ranked as Hack ASW〉Nakamula ASW〉Schmadz ASW〉NSW〉Oshima ASW〉Subow ASW, and was again higher in rice media than in beef extract media （except for Subow ASW）; （3） the exponential and stationary phases were longer in rice media than in beef extract media; （4） strains of E. vannus that had been domesticated for 〉1 year in ASW grew significantly slower, with lower maximum density and longer stationary phase than those isolated and maintained in NSW. It was demonstrated that： （1） E. vannus may grow well in Flack, Nakamula and Schmads ASW compared with NSW （mainly in terms of growth rate）; and （2） Oshima ASW is the preferred choice for stock cultures of E. vannus, but the ASWs Flack, Nakamula and Schmadz are preferred for mass culture. These findings suggest that these three ASWs are effective for the cultivation of marine protozoa for experimental studies on ecology, toxicology and molecular biology.展开更多
The living morphology and infraciliature of two rare marine ciliates, Placussalinus Dietz, 1964 and Strombidium apolatum Wilbert and Song, 2005, collected from the coastalwaters near Qingdao, China, were investigated ...The living morphology and infraciliature of two rare marine ciliates, Placussalinus Dietz, 1964 and Strombidium apolatum Wilbert and Song, 2005, collected from the coastalwaters near Qingdao, China, were investigated by in vivo observation and protargol impregnationtechnique. The improved diagnosis for Placus salinus is as follows: medium-sized marine Placus, invivo (50-60) μm X (30-40) μm; cell elliptical to barrel-shaped; 28-31 somatic kineties; singlemacronucleus usually ellipsoid and one micronucleus located in the indention of the macronucleus;one contractile vacuole posteriorly positioned. Strombidium apolatum is characterized by: marinestrombidium (40-60) μm X (30-45) μm in vivo, cordiform in shape with somewhat pointed posteriorend and conspicuous apical protrusion; extrusomes prominent, about 15 μm in length and evenlyarranged along the circle kinety; about 16 collar and 5-6 buccal membranelles; one elongatemacronucleus and one micronucleus; circle and ventral kineties consisting of about 53 and 45dikinetids respectively.展开更多
Ciliated hepatic foregut cyst (CHFC) is a very rare cystic lesion of the liver that is histologically similar to bronchogenic cyst. We report one case of CHFC that was hard to distinguish from solid-cystic neoplasm in...Ciliated hepatic foregut cyst (CHFC) is a very rare cystic lesion of the liver that is histologically similar to bronchogenic cyst. We report one case of CHFC that was hard to distinguish from solid-cystic neoplasm in imaging features. Magnetic resonance imaging was helpful in differentiating these cysts from other lesions.展开更多
The ciliate community in the Bohai Sea (China) was studied from 23 September to 7 October 1998. A hurricane struck the study area between the two grid station investigations, which were six days apart. Six tintinnid s...The ciliate community in the Bohai Sea (China) was studied from 23 September to 7 October 1998. A hurricane struck the study area between the two grid station investigations, which were six days apart. Six tintinnid species (Favella panamensis, Leptotintinnus nordqvisti, Tintinnopsis butschlii, T. karajacensis, T. Radix and Wangiella dicollaria) were identified. Total cililate abundance in the surface layer ranged from 20 to 770 ind/l. In the first grid investigation, Tintinnopsis karajacensis dominated in the warm, low salinity waters at the Huanghe River mouth. Aloricate ciliate sp.1 dominated in the cold, high salinity waters in the northwest of the study area and the Bohai Strait. In the second grid investigation, T. Karajacensis almost disappeared. The abundance of aloricate ciliate sp.1 decreased drastically. The aloricate ciliate sp.2 dominated at the Bohai Strait. The change of ciliate abundance may be due to the disturbance of hurricane.展开更多
The Yellow Sea Cold Water Mass(YSCWM)is a distinct hydrographic phenomenon of the Yellow Sea,and the distribution pattern of meio-and macrobenthos diff ers inside and outside of the YSCWM.However,such a pattern has ne...The Yellow Sea Cold Water Mass(YSCWM)is a distinct hydrographic phenomenon of the Yellow Sea,and the distribution pattern of meio-and macrobenthos diff ers inside and outside of the YSCWM.However,such a pattern has never been observed in the microbenthic ciliate communities.Therefore,we hypothesized that benthic ciliates followed a similar distribution pattern as meio-and macrobenthos,but this pattern has not been uncovered by morphological methods.We evaluated the diversity and distribution of benthic ciliates at fi ve stations along hydrographic gradients across the YSCWM and adjacent shallow water by using morphology and DNA and complementary DNA(cDNA)high-throughput sequencing of the V4 region of 18S rRNA gene.Results showed that the diversity of benthic ciliates detected by DNA(303 OTUs),and the cDNA(611 OTUs)sequencing was much higher than that detected by the morphological method(79 species).Morphological method detected roughly diff erent ciliate communities inside and outside of the YSCWM,but without statistical signifi cance.No clear pattern was obtained by DNA sequencing.In contrast,cDNA sequencing revealed a distinct distribution pattern of benthic ciliate communities like meioand macrobenthos,which coincided well with the results of the environmental parameter analysis.More than half of the total sequences detected by DNA sequencing belonged to planktonic ciliates,most(if not all)of which were recovered from historic DNA originating through the sedimentation of pelagic forms because none of them were observed morphologically.The irrelevant historic DNA greatly infl uenced the recovery of rare species and thus limited the understanding of the benthic ciliate diversity and distribution.Our research indicates that the methods used have signifi cant eff ects on the investigation of benthic ciliate communities and highlights that cDNA sequencing has great advantages in estimating the diversity and distribution of benthic ciliates,as well as the potential for benthic environmental assessments.展开更多
Trait structure is increasingly used in plankton ecology to understand diversity and biogeography.However,our knowledge of micro zooplankton(e.g.planktonic ciliates)trait structure and its variation with hydrography i...Trait structure is increasingly used in plankton ecology to understand diversity and biogeography.However,our knowledge of micro zooplankton(e.g.planktonic ciliates)trait structure and its variation with hydrography is limited.In this study,we analyzed planktonic ciliate trait structure in waters with different hydrography and deep Chlorophyll a maximum(DCM)layers over three seamounts:Yap,Mariana,and Caroline seamounts.Mariana seamount had a lower surface temperature than the Yap and Caroline seamounts.DCM layers over Mariana and Caroline seamounts were deeper than Yap seamount.There was a weak upwelling in upper 50 m around top of Mariana seamount.The ciliate distribution showed bimodal pattern(high abundance appeared in the surface and DCM layers)over three seamounts.At surface layer,the large size-fraction(>30μm)abundance proportion to aloricate ciliate over Yap seamount(44.4%)was higher than Mariana(32.8%)and Caroline(36.1%)seamounts.For tintinnid abundance proportion to total ciliate,Mariana(12.0%)and Caroline(11.5%)seamounts at about 100-m depth were higher than that of Yap seamount(6.4%).Vertically,tintinnid could be divided into 4 groups over the three seamounts.At30-m depth,group I(species occurring from surface to 100 m only)was dominant component over Yap and Caroline seamounts,while group IV(species occurring at every depth)changed into dominant component over Mariana seamount,the weak upwelling might be the reason.Salpingella faurei was the top dominant species,which corresponded to deeper DCM layers over Mariana and Caroline seamounts.Our results showed that the upwelling and the deeper DCM could influence the planktonic ciliate trait structure.展开更多
We reinvestigate the morphology of two oligotrich and two hypotrich ciliates collected from the coasts of north and south China,viz.,Parallelostrombidium obesum Liu et al.,2015,Spirostrombidium apourceolare Liu et al....We reinvestigate the morphology of two oligotrich and two hypotrich ciliates collected from the coasts of north and south China,viz.,Parallelostrombidium obesum Liu et al.,2015,Spirostrombidium apourceolare Liu et al.,2013,Protogastrostyla pulchra(Pereyaslawzewa,1886)Gong et al.,2007,and Uncinata bradburyae(Gong et al.,2001)Luo et al.,2015.All the populations match well with the original samples identified in previous studies.Supplemental taxonomic data were supplied for these four species of the new populations.The species Parallelostrombidium obesum is characterised by its dorsal-ventrally flattened body shape with anterior and posterior ends transversely truncating,as well as two thigmotactic membranelles and girdle kinety that spirals around the cell one and a half times.Spirostrombidium apourceolare is characterised by its elongate ellipsoidal and dorsal-ventrally flattened body shape,two thigmotactic membranelles,about 11-27 ovoid macronuclear nodules,and girdle kinety that spirals around the cell twice with two undulations.Protogastrostyla pulchra is characterised by its elongate body shape and unique,caudally located food vacuole.Based on the new populations,we described the smaller cortical granules,clustered around dorsal bristles for the first time.The new population of Uncinata bradburyae shares the diagnostic features with the type population,which include prominent beak-like projection in anterior region,the conspicuous gap of adoral zone,proximalmost adoral membranelles distinctly elongated,and infraciliature.展开更多
The morphology and infraciliature of a new marine colepid ciliate, A＇pocoleps magnus gen. nov., spec. nov., are de- scribed based on living observations and silver impregnations. The new genus Apocoleps is characteri...The morphology and infraciliature of a new marine colepid ciliate, A＇pocoleps magnus gen. nov., spec. nov., are de- scribed based on living observations and silver impregnations. The new genus Apocoleps is characterized by having 8 （vs. 6 in most other related genera） armour tiers, spines at both ends of the cell, 3 adoral organelles and plates with 4 reniform uni-windows. Apo- coleps magnus spec. nov. is defined by the following features： body elongated and slightly curved, about 100-120p.mx 3545 lam in vivo; anterior tertiary tier plate with four uni-windows, most secondary and main tier plates with four uni-windows, posterior tertiary tier plate with two uni-windows; left plate margin slightly serrated; on average 23 transverse and 22 longitudinal ciliary rows; one terminal contractile vacuole; marine habitat.展开更多
One new marine oligotrich ciliate, Omegastrombidium hongkongense n. sp., was isolated from a bloom of Noctiluca scuntillans near Port Shelter, Hong Kong. The morphology and infraciliature of this new species were stud...One new marine oligotrich ciliate, Omegastrombidium hongkongense n. sp., was isolated from a bloom of Noctiluca scuntillans near Port Shelter, Hong Kong. The morphology and infraciliature of this new species were studied on both living and protargol-stained specimens. Its phylogenetic position was discussed based on the sequence of the small subunit r RNA gene. O. hongkongense is different from its congeners with special characters. The cells are usually heart-shaped, and the cell size usually is(20–35) ×(20–30) μm in vivo. Its deep buccal cavity extends obliquely to about 1/2 of cell length. It shows prominent apical protrusion. The adoral zone of membranelles is divided into 17–19 collar membranelles and four buccal membranelles. It has one ball-like macronucleus. The girdle kinety forms a closed loop which obliquely surrounds the body. The ventral kinety and thigmotactic membranelles are not observed. The SSU r RNA sequence of O. hongkongense was close to those of Strombidium paracalkinsi and Varistrombidium kelum with approximately 99% similarity. In the phylogenetic trees, O. hongkongense can be grouped with O. elegans and V. kielum species with very low support(16% ML).展开更多
Magnetotactic bacteria(MTB)are a group of prokaryotes having the ability to orient and swim along geomagnetic field lines because they contain intracellular magnetosomes that are synthesized through a biomineralizatio...Magnetotactic bacteria(MTB)are a group of prokaryotes having the ability to orient and swim along geomagnetic field lines because they contain intracellular magnetosomes that are synthesized through a biomineralization process.Magnetosomes have recently also been found in unicellular eukaryotes,which are referred to as magnetically responsive protists(MRPs).The magnetosomes have three origins in MRPs.In this study,we characterized a MTB-grazing ciliated MRP that was magnetically collected from intertidal sediment of Huiquan Bay,Qingdao,China.Based on 18S rRNA gene sequence analysis,the ciliated MRP was tentatively identified as Uronemella parafi lificum HQ.Using transmission electron microscopy,we observed that magnetosomes having 2-3 shapes were randomly distributed within this ciliate.Energydispersive X-ray spectroscopy and high-resolution transmission electron microscopy images of the magnetosomes were consistent with them being composed of magnetite.Magnetosomes having the same shape and mineral composition were also detected in MTB that occurred in the same environment as the ciliated MRP.Statistical analysis showed that the size and shape of the magnetosomes in the ciliated MRP were similar to those in MTB.The results suggest that this ciliated MRP can graze,ingest,and digest various types of MTB.It is certainly worth noting that this is the first record of MRPs in Asian aquatic sediment and suggesting they might be widely distributed.These results also support the assertion that MRPs probably contribute to the ecological cycles of iron,and expand possibilities for research into the mechanism of magnetoreception in eukaryotes.展开更多
We examined the structure and spatial organization of ciliature base-associated microtubules （BAM） in three hypotrichous ciliates （Stylonychia mytilus, Pseudourostyla cristata, Euplotes woodruffi） in fluorescence ...We examined the structure and spatial organization of ciliature base-associated microtubules （BAM） in three hypotrichous ciliates （Stylonychia mytilus, Pseudourostyla cristata, Euplotes woodruffi） in fluorescence microscopy. The results revealed that BAM, including the anterior （ALM）, posterior longitudinal microtubule （PLM） and the transverse microtubule （TM） bands, are composed of tubulin. The respective microtubular bands have cytoplasmic polarization patterns that are significantly asymmetric. The BAM of the midventral files in P. cristata appear cord-shaped compared with the ALM bands of transverse cirri in both S. mytilus and E. woodruffi, which extend to the left anterior side of the cell before converging. The TM bands of the left marginal cirri （MC） in S. rnytilus extend to the right side of the cell, while those of the right MC bands extend to the left. Our observations suggest that BAM traits are common in hypotrichous ciliates even though different species possess different microtubule arrangements related to the conserved cirral morphogenetic patterns in the respective species. The differing development of BAM in the three ciliate suggests that the microtubules may be conserved in different hypotrichs. We have also demonstrated that the BAM, which appear polar and asymmetric, are localized in specific cytoskeletal positions and extend in different orientations within the cortex to connect with other ciliature-associated structures and, thus, strengthen the cortex. These BAM features indicate that they are directly associated with cell motion.展开更多
Chromosomes are well-organized carriers of genetic information in eukaryotes and are usually quite long,carrying hundreds and thousands of genes.Intriguingly,a clade of single-celled ciliates,Spirotrichea,feature nano...Chromosomes are well-organized carriers of genetic information in eukaryotes and are usually quite long,carrying hundreds and thousands of genes.Intriguingly,a clade of single-celled ciliates,Spirotrichea,feature nanochromosomes—also called“gene-sized chromosomes”.These chromosomes predominantly carry only one gene,flanked by short telomere sequences.However,the organization and copy number variation of the chromosomes in these highly fragmented genomes remain unexplored in many groups of Spirotrichea,including the marine Strombidium.Using deep genome sequencing,we assembled the macronuclear genome of Strombidium stylifer into more than 18,000 nanochromosomes(~2.4 Kb long on average).Our results show that S.stylifer occupies an intermediate position during the evolutionary history of Strombidium lineage and experienced significant expansions in several gene families related to guanyl ribonucleotide binding.Based on the nucleotide distribution bias analysis and conserved motifs search in non-genic regions,we found that the subtelomeric regions have a conserved adenine-thymine(AT)-rich sequence motif.We also found that the copy number of nanochromosomes lacks precise regulation.This work sheds light on the unique features of chromosome structure in eukaryotes with highly fragmented genomes and reveals that a rather specialized evolutionary strategy at the genomic level has resulted in great diversity within the ciliated lineages.展开更多
基金Supported by Forestry Science and Technology Planning Program(XLK201406)~~
文摘ln order to discuss the optimum seedling density of Toona ciliate, different seedling densities were studied. The results showed that seeding height and basal diameter decreased and quality of the seedlings declined with the increase of seedling density. The reasonable density of seedlings is key to cultivate high-quality seedlings and achieve the best seedling efficiency. The optimum density was 30 plants/m2 for the first class seedlings of biennial seedlings, and the optimum density of l and ll seedlings for production afforestation was 40 plants/m2.
基金The National Natural Science Foundation of China under contract Nos 41522604,31572255 and 31301867the Strategic Priority Research Program of CAS under contract No.XDA11020702the CAS Key Research Program of Frontier Sciences under contract No.QYZDB-SSW-DQC013
文摘This study explored the molecular diversity and biogeography of benthic ciliates in Chinese marginal seas, the Bohai Sea(BHS), North Yellow Sea(NYS) and South Yellow Sea(SYS). From a previous 18S rRNA gene pyrosequencing dataset of the benthic microeukaryotes, we retrieved the sequences affiliated with phylum Ciliophora and analyzed alpha and beta diversities of ciliate communities. We found that BHS had the highest ciliate operational taxonomic unit(OTU) richness than NYS and SYS, whereas the richness was not significantly different between summer and winter. Among all the measured environmental variables, water depth showed consistently the strongest correlations with alpha diversities. Overall, the class Spirotrichea(mostly Choreotrichia and unassigned lineages within the class) dominated the communities in terms of both relative proportion of sequences(77.0%) and OTU richness(66.5%). OTU-level ciliate community structure was significant different among the three basins, but not between the seasons. Structurally, significant differences in relative proportion among the basins were detected for the class Litostomatea, but not for other classes. Partial Mantel tests demonstrated that water depth difference was more important than geographic and environment distances in shaping the community structure of benthic ciliates in the studied area. About 60% OTUs were not assigned at a class or order level and at least 45% OTUs shared a sequence similarity no more than 97% with the described species, indicating a great potential for ciliate species discovery in the offshore sediments. Compared with previous morphology-based surveys, the spatial pattern of ciliate diversity(decreasing from NYS to SYS) is also identified in the present study. Nevertheless, structurally, the dominant class appeared to be Spirotrichea in the sequencing dataset, which differs from previous morphology-based results(dominance of classes Prostomatea and Karyorelictea in biomass). The potential causes for the discrepancies between molecular and morphological findings are also discussed.
文摘The tolerance to ammonia and nitrites in freshwater ciliate Paramecium bursaria was measured in a conventional open system. The ciliate was exposed to different concentrations of ammonia and nitrites for 2h and 12h in order to determine the lethal concentrations. Linear regression analysis revealed that the 2h-LC50 value for ammonia was 95.94 mg/L and for nitrite 27.35 mg/L using probit scale method (with 95% confidence intervals). There was a linear correlation between the mortality probit scale and logarithmic concentration of ammonia which fit by a regression equation y=7.32x–9.51 (R2=0.98; y, mortality probit scale; x, logarithmic concentration of ammonia), by which 2 h–LC50 value for ammonia was found to be 95.50 mg/L. A linear correla- tion between mortality probit scales and logarithmic concentration of nitrite is also followed the regression equa- tion y=2.86x+0.89 (R2=0.95; y, mortality probit scale; x, logarithmic concentration of nitrite). The regression analysis of toxicity curves showed that the linear correlation between exposed time of ammonia-N LC50 value and ammonia-N LC50 value followed the regression equation y=2 862.85e-0.08x (R2=0.95; y, duration of exposure to LC50 value; x, LC50 value), and that between exposed time of nitrite-N LC50 value and nitrite-N LC50 value followed the regression equation y = 127.15e-0.13x (R2=0.91; y, exposed time of LC50 value; x, LC50 value). The results demonstrate that the tolerance to ammonia in P. bursaria is considerably higher than that of the larvae or juveniles of some metozoa, e.g. cultured prawns and oysters. In addition, ciliates, as bacterial predators, are likely to play a positive role in maintaining and improving water quality in aquatic environments with high-level ammonium, such as sewage treatment systems.
基金Supported by the National Basic Research Program of China(973 Program)(No.2011CB403604)the National Natural Science Foundation of China(Nos.41476144,41306153)
文摘The annual bloom of the green macroalgal Ulva prolifera from May through July since 2008 and another of giant jellyfi sh Nemopilema nomurai from June through September have been frequent events in the Yellow Sea. However, the patterns of benthic ciliate communities during and after the blooms are still not known. In combination with analyses of benthic environmental factors, we investigated the distribution and community composition of benthic ciliates in the Yellow Sea in July and November 2011. In July, ciliates had high standing crops and diversity in the northern Yellow Sea, and in the inshore area off the southern Shandong Peninsula, where large numbers of green macroalgae accumulated. In November, the abundance, biomass and diversity of ciliates were high in the sea areas off the Shandong Peninsula and Changjiang estuary, where a large quantity of jellyfi sh occurred in August. Neither the abundance nor the biomass had signifi cant diff erence between seasons, or between diff erent compartments of the Yellow Sea. The species number, and both Margalef and Shannon-Wiener indices of ciliates were all signifi cantly higher in November than in July. In both seasons, prostomateans and karyorelicteans consistently constituted the fi rst and second most important ciliate groups in biomass; and carnivorous ciliates constituted the primary feeding type in terms of biomass as well as species richness, followed by bacterivores, algivores and omnivores. Compared with that in June 2007 when no macroalgae occurred, the percentage of small-sized bacterivores(e.g. Metacystis spp., Euplotes spp. and scuticociliates) increased in July 2011. The proportion of carnivorous ciliates increased in November, and this increased dominance of carnivorous ciliates may be a response to the increase in predominance of heterotrophic nanofl agellates, which might in turn be ascribed to an eff ect of green macroalgal and giant jellyfi sh blooms in the Yellow Sea.
基金The National Natural Science Foundation of China under contract No.41130855Key Laboratory for Exploitation&Utilization ofMarine Fisheries Reource in South China Sea,Ministry of Agriculture under contract No.LSF2011-05Financial Fund of the Ministry of Agricultureunder contract No.NFZX2013
文摘Ciliates play a curial role in energy transfer from pico- and nano-phytoplankton to mesozooplankton in marine ecosystems. In order to visualize their geographical distributions from the Java Sea to the South China Sea （6~S to 20~N）, the authors investigated the ciliate abundance and species composition in sur- face waters during May 18 to 27 of 2010. The ciliate abundance decreased latitudinally from 3 080 ind./L （~6~S） to 40 ind./L （-~3~N）, and then increased to 1 180 ind./L （-~ 16~N） at the end of the survey. A total of 22 ciliates belonging to 15 genera were identified with the tintinnids accounted for 50% （11 species）; and the species number showed a same spatial change as the ciliate abundance. Moreover, the Strombidium oc- cupied over 50% of total ciliate abundance in most stations and Mesodiniurn and Tintinnopsis contributed to about 18.7% and 11.4%, respectively. In particular, our results indicate that the geographical changes in ciliate abundance were positively regulated by larger nano- and micro-phytoplankton biomass, rather than smaller pico-phytoplankton in the investigated waters.
基金Supported by the Korea Research Foundation Grant to J.K.CHOI (No.KRF-2008-013-C00064)the Knowledge Innovation Program of Chinese Academy of Sciences (No.KZCX2-YW-417)the National Natural Science Foundation of China (No.40576072,40706047)
文摘We assessed the potential of marine ciliate community as an indicator to coastal water quality using water samples collected from four stations in thc Yellow Sea in the summer 2000. The four stations were characterized by different levels of pollution. The ciliate communities consisted primarily of tintinnids and aloricate ciliates that were 〈30 um. A total of 78 species were classified： 55 species at Station 2, 51 species each at Stations l and 4, and 47 species at Station 3. The mean number of species at each site was 29.2±2.0 （Station 1）, 28.5±2.9 （Station 2）, 27.8±1.7 （Station 3）, and 24.5±2.3 （Station 4）. The abundance was highly variable： 19 331±11 187 ind./L at Station 1, 7 960±5 639 ind./L at Station 2, 29 015±12 999 ind./L at Station 3, and 8 190±4 658 ind./L at Station 4. Our results suggest that neither the simple chemical analysis （e.g. chemical oxygen demand, dissolved inorganic nitrogen, and phosphate） nor the eutrophication/pollution index adequately described the water quality at the four stations. The same was true of the number of species and their abundance, both of which had no correlation with the chemical indices. In contrast, Margalef＇s diversity index values （3.12 at Station 2, 2.89 at Station 1, and 2.64 at Stations 3 and 4） generally discriminated the water quality status of the four stations. The difference in water quality among the stations was strongly supported by the pattern of species richness （i.e. the total number of species） of ciliates at each station. Our evaluation was consistent with the results of long-term water quality monitoring at the four stations. With increasing eutrophication, we observed also a compositional and functional shift in the ciliate assemblages from algivorous oligotrich/choreotrich to nonselective-omnivorous gymnostomatids to bacterivorous-detrivorous scuticociliatids. Thus, eiliates may be used to indicate the coastal water quality status of a given site.
基金The National Natural Science Foundation of China under contract No.41706192the Science&Technology Basic Resources Investigation Program of China under contract No.2017FY100803+3 种基金the National Natural Science Foundation of ChinaShandong Joint Fund for Marine Science Research Centers under contract No.U1606404the CNRS-NSFC Joint Research Projects Program under contract No.NSFC 41711530149the 2017–2019 Sino-French Cai Yuanpei Programmethe National Natural Science Foundation of China under contract No.41706217
文摘Ciliates are important components in planktonic food webs,but our understanding of their community structures in different oceanic water masses is limited.We report pelagic ciliate community characteristics in three seas:the tropical West Pacific,the Bering Sea and the Arctic Ocean.Planktonic ciliate abundance had"bimodal-peak","surface-peak"and"DCM(deep chlorophyll a maximum layer)-peak"vertical distribution patterns in the tropical West Pacific,the Bering Sea and the Arctic Ocean,respectively.The abundance proportion of tintinnid to total ciliate in the Bering Sea(42.6%)was higher than both the tropical West Pacific(7.8%)and the Arctic Ocean(2.0%).The abundance proportion of small aloricate ciliates(10–20μm size-fraction)in the tropical West Pacific was highest in these three seas.The Arctic Ocean had higher abundance proportion of tintinnids in larger LOD(lorica oral diameter)size-class.Proportion of redundant species increased from the Arctic Ocean to the tropical West Pacific.Our result provided useful data to further understand ecology roles of planktonic ciliates in different marine habitats.
基金supported by the National Basic Research Program of China (2014CB441500)Special Fund for Agro-scientific Research in the Public Interest (201403008)Major Project of Ministry of Agriculture (NFZX2013)
文摘Ciliates are very important components in most marine ecosystem. They are trophic link between the microbial food web and grazing food chain. In this study, ciliates were collected from 11 sites in the southern South China Sea （SCS） during August 25 to September 28, 2011. Their composition and distribution at the surface and 75m deep depth of the ocean were studied. A total of 30 species belonging to 22 genera were identified, and 22 species of 15 genera were Tintinnids. Eutintinnusfraknoii and E. stramentus were the most common species. The other dominants were strombidiids ciliates including Strombidium conicum and S. globosaneum, which were followed by the tide form, Mesodinium pulex. Ciliates abundance ranged from 46 indL-1 to 368 indL-1 in the open sites, 46-368indL-1 at surface and 73-198indL-1 at 75m deep layer. In the Yongshu reef, ciliates abundance ranged from 167indL-1 to 365 ind L-1 in the water colunm, similar to that in Sanya coral reef waters. Ciliates composition showed obvious difference between surface and 75m deep layer at station S2 （P〈0.05）, while no similar result was observed at other sites. At 75m deep layer, salinity was negatively related to mixed layer depth （P〈 0.05）, but positively to chlorophyll a concentration （P〈 0.05）, indicating that the change of vertical mixing in water column influenced vertical distribution of ciliates in the southern SCS.
基金Supported by the National Natural Science foundation of China (Nos.41076089,40976075)a Post-Doctoral Fellowship by Inha University awarded to XU Henglong+1 种基金a Grant from the Center of Excellence in Biodiversity Research,King Saud Universitythe 111 Project of China (No.B08049)
文摘To study population dynamics of marine ciliates in different artificial seawaters （ASW）, the population growth dynamics of a common marine ciliate Euplotes vannus were investigated using beef extract media and rice media for five types of ASW and natural seawater （NSW）. The results show that： （1） the population growth rate was in the order of NSW〉Flack ASW〉Nakamula ASW〉Schmadz ASW〉Oshima ASW〉Subow ASW and was considerably higher in rice media than in beef extract media （apart from Subow ASW）; （2） the maximum density of E. vannus in stationary phase in each treatment was ranked as Hack ASW〉Nakamula ASW〉Schmadz ASW〉NSW〉Oshima ASW〉Subow ASW, and was again higher in rice media than in beef extract media （except for Subow ASW）; （3） the exponential and stationary phases were longer in rice media than in beef extract media; （4） strains of E. vannus that had been domesticated for 〉1 year in ASW grew significantly slower, with lower maximum density and longer stationary phase than those isolated and maintained in NSW. It was demonstrated that： （1） E. vannus may grow well in Flack, Nakamula and Schmads ASW compared with NSW （mainly in terms of growth rate）; and （2） Oshima ASW is the preferred choice for stock cultures of E. vannus, but the ASWs Flack, Nakamula and Schmadz are preferred for mass culture. These findings suggest that these three ASWs are effective for the cultivation of marine protozoa for experimental studies on ecology, toxicology and molecular biology.
基金supported by‘The National Science Foundation of China’(Nos.40376045,30430090)
文摘The living morphology and infraciliature of two rare marine ciliates, Placussalinus Dietz, 1964 and Strombidium apolatum Wilbert and Song, 2005, collected from the coastalwaters near Qingdao, China, were investigated by in vivo observation and protargol impregnationtechnique. The improved diagnosis for Placus salinus is as follows: medium-sized marine Placus, invivo (50-60) μm X (30-40) μm; cell elliptical to barrel-shaped; 28-31 somatic kineties; singlemacronucleus usually ellipsoid and one micronucleus located in the indention of the macronucleus;one contractile vacuole posteriorly positioned. Strombidium apolatum is characterized by: marinestrombidium (40-60) μm X (30-45) μm in vivo, cordiform in shape with somewhat pointed posteriorend and conspicuous apical protrusion; extrusomes prominent, about 15 μm in length and evenlyarranged along the circle kinety; about 16 collar and 5-6 buccal membranelles; one elongatemacronucleus and one micronucleus; circle and ventral kineties consisting of about 53 and 45dikinetids respectively.
文摘Ciliated hepatic foregut cyst (CHFC) is a very rare cystic lesion of the liver that is histologically similar to bronchogenic cyst. We report one case of CHFC that was hard to distinguish from solid-cystic neoplasm in imaging features. Magnetic resonance imaging was helpful in differentiating these cysts from other lesions.
文摘The ciliate community in the Bohai Sea (China) was studied from 23 September to 7 October 1998. A hurricane struck the study area between the two grid station investigations, which were six days apart. Six tintinnid species (Favella panamensis, Leptotintinnus nordqvisti, Tintinnopsis butschlii, T. karajacensis, T. Radix and Wangiella dicollaria) were identified. Total cililate abundance in the surface layer ranged from 20 to 770 ind/l. In the first grid investigation, Tintinnopsis karajacensis dominated in the warm, low salinity waters at the Huanghe River mouth. Aloricate ciliate sp.1 dominated in the cold, high salinity waters in the northwest of the study area and the Bohai Strait. In the second grid investigation, T. Karajacensis almost disappeared. The abundance of aloricate ciliate sp.1 decreased drastically. The aloricate ciliate sp.2 dominated at the Bohai Strait. The change of ciliate abundance may be due to the disturbance of hurricane.
基金Supported by the National Natural Science Foundation of China(Nos.41876171,41506167,41476144)。
文摘The Yellow Sea Cold Water Mass(YSCWM)is a distinct hydrographic phenomenon of the Yellow Sea,and the distribution pattern of meio-and macrobenthos diff ers inside and outside of the YSCWM.However,such a pattern has never been observed in the microbenthic ciliate communities.Therefore,we hypothesized that benthic ciliates followed a similar distribution pattern as meio-and macrobenthos,but this pattern has not been uncovered by morphological methods.We evaluated the diversity and distribution of benthic ciliates at fi ve stations along hydrographic gradients across the YSCWM and adjacent shallow water by using morphology and DNA and complementary DNA(cDNA)high-throughput sequencing of the V4 region of 18S rRNA gene.Results showed that the diversity of benthic ciliates detected by DNA(303 OTUs),and the cDNA(611 OTUs)sequencing was much higher than that detected by the morphological method(79 species).Morphological method detected roughly diff erent ciliate communities inside and outside of the YSCWM,but without statistical signifi cance.No clear pattern was obtained by DNA sequencing.In contrast,cDNA sequencing revealed a distinct distribution pattern of benthic ciliate communities like meioand macrobenthos,which coincided well with the results of the environmental parameter analysis.More than half of the total sequences detected by DNA sequencing belonged to planktonic ciliates,most(if not all)of which were recovered from historic DNA originating through the sedimentation of pelagic forms because none of them were observed morphologically.The irrelevant historic DNA greatly infl uenced the recovery of rare species and thus limited the understanding of the benthic ciliate diversity and distribution.Our research indicates that the methods used have signifi cant eff ects on the investigation of benthic ciliate communities and highlights that cDNA sequencing has great advantages in estimating the diversity and distribution of benthic ciliates,as well as the potential for benthic environmental assessments.
基金the Science&Technology Basic Resources Investigation Program of China(No.2017FY100803)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB42000000)+5 种基金the China Postdoctoral Science Foundation(No.2020M672149)the National Key Research and Development Program of China(No.2017YFA0603204)the CNRS-NSFC Joint Research Projects Program(No.NSFC 41711530149)the 2017-2019 Sino-French Cai Yuanpei Programthe International Cooperation Project-Dynamics and Function of Marine Microorganisms(No.ICP-DYF2M):Insight from Physics and Remote Sensing。
文摘Trait structure is increasingly used in plankton ecology to understand diversity and biogeography.However,our knowledge of micro zooplankton(e.g.planktonic ciliates)trait structure and its variation with hydrography is limited.In this study,we analyzed planktonic ciliate trait structure in waters with different hydrography and deep Chlorophyll a maximum(DCM)layers over three seamounts:Yap,Mariana,and Caroline seamounts.Mariana seamount had a lower surface temperature than the Yap and Caroline seamounts.DCM layers over Mariana and Caroline seamounts were deeper than Yap seamount.There was a weak upwelling in upper 50 m around top of Mariana seamount.The ciliate distribution showed bimodal pattern(high abundance appeared in the surface and DCM layers)over three seamounts.At surface layer,the large size-fraction(>30μm)abundance proportion to aloricate ciliate over Yap seamount(44.4%)was higher than Mariana(32.8%)and Caroline(36.1%)seamounts.For tintinnid abundance proportion to total ciliate,Mariana(12.0%)and Caroline(11.5%)seamounts at about 100-m depth were higher than that of Yap seamount(6.4%).Vertically,tintinnid could be divided into 4 groups over the three seamounts.At30-m depth,group I(species occurring from surface to 100 m only)was dominant component over Yap and Caroline seamounts,while group IV(species occurring at every depth)changed into dominant component over Mariana seamount,the weak upwelling might be the reason.Salpingella faurei was the top dominant species,which corresponded to deeper DCM layers over Mariana and Caroline seamounts.Our results showed that the upwelling and the deeper DCM could influence the planktonic ciliate trait structure.
基金supported by the National Natural Science Foundation of China(Nos.31801955,31702009)the China Postdoctoral Science Foundation(Nos.2017M622276,BX20180348)
文摘We reinvestigate the morphology of two oligotrich and two hypotrich ciliates collected from the coasts of north and south China,viz.,Parallelostrombidium obesum Liu et al.,2015,Spirostrombidium apourceolare Liu et al.,2013,Protogastrostyla pulchra(Pereyaslawzewa,1886)Gong et al.,2007,and Uncinata bradburyae(Gong et al.,2001)Luo et al.,2015.All the populations match well with the original samples identified in previous studies.Supplemental taxonomic data were supplied for these four species of the new populations.The species Parallelostrombidium obesum is characterised by its dorsal-ventrally flattened body shape with anterior and posterior ends transversely truncating,as well as two thigmotactic membranelles and girdle kinety that spirals around the cell one and a half times.Spirostrombidium apourceolare is characterised by its elongate ellipsoidal and dorsal-ventrally flattened body shape,two thigmotactic membranelles,about 11-27 ovoid macronuclear nodules,and girdle kinety that spirals around the cell twice with two undulations.Protogastrostyla pulchra is characterised by its elongate body shape and unique,caudally located food vacuole.Based on the new populations,we described the smaller cortical granules,clustered around dorsal bristles for the first time.The new population of Uncinata bradburyae shares the diagnostic features with the type population,which include prominent beak-like projection in anterior region,the conspicuous gap of adoral zone,proximalmost adoral membranelles distinctly elongated,and infraciliature.
基金supported by ‘the Natural Science Foundation of China’ (Project No. 30870264)the Darwin Initiative Programme (Project No. 14-015)
文摘The morphology and infraciliature of a new marine colepid ciliate, A＇pocoleps magnus gen. nov., spec. nov., are de- scribed based on living observations and silver impregnations. The new genus Apocoleps is characterized by having 8 （vs. 6 in most other related genera） armour tiers, spines at both ends of the cell, 3 adoral organelles and plates with 4 reniform uni-windows. Apo- coleps magnus spec. nov. is defined by the following features： body elongated and slightly curved, about 100-120p.mx 3545 lam in vivo; anterior tertiary tier plate with four uni-windows, most secondary and main tier plates with four uni-windows, posterior tertiary tier plate with two uni-windows; left plate margin slightly serrated; on average 23 transverse and 22 longitudinal ciliary rows; one terminal contractile vacuole; marine habitat.
基金supported by the National Natural Science Foundation of China(No.31301868)the Hong Kong Research Grants Council(Nos.GRF 661610 and 661912)+2 种基金the Hong Kong Scholar Programme(No.HKSP13SC03)NSFC-Guangdong Province Joint Foundation(No.U1301 235)Natural Science Foundation of Guangdong Pro-vince(No.S2013040013192)
文摘One new marine oligotrich ciliate, Omegastrombidium hongkongense n. sp., was isolated from a bloom of Noctiluca scuntillans near Port Shelter, Hong Kong. The morphology and infraciliature of this new species were studied on both living and protargol-stained specimens. Its phylogenetic position was discussed based on the sequence of the small subunit r RNA gene. O. hongkongense is different from its congeners with special characters. The cells are usually heart-shaped, and the cell size usually is(20–35) ×(20–30) μm in vivo. Its deep buccal cavity extends obliquely to about 1/2 of cell length. It shows prominent apical protrusion. The adoral zone of membranelles is divided into 17–19 collar membranelles and four buccal membranelles. It has one ball-like macronucleus. The girdle kinety forms a closed loop which obliquely surrounds the body. The ventral kinety and thigmotactic membranelles are not observed. The SSU r RNA sequence of O. hongkongense was close to those of Strombidium paracalkinsi and Varistrombidium kelum with approximately 99% similarity. In the phylogenetic trees, O. hongkongense can be grouped with O. elegans and V. kielum species with very low support(16% ML).
基金Supported by the National Natural Science Foundation of China(Nos.41776130,41776131)the National Natural Science Foundation of China-Shandong Joint Fund for Marine Science Research Centers(No.U1706208)。
文摘Magnetotactic bacteria(MTB)are a group of prokaryotes having the ability to orient and swim along geomagnetic field lines because they contain intracellular magnetosomes that are synthesized through a biomineralization process.Magnetosomes have recently also been found in unicellular eukaryotes,which are referred to as magnetically responsive protists(MRPs).The magnetosomes have three origins in MRPs.In this study,we characterized a MTB-grazing ciliated MRP that was magnetically collected from intertidal sediment of Huiquan Bay,Qingdao,China.Based on 18S rRNA gene sequence analysis,the ciliated MRP was tentatively identified as Uronemella parafi lificum HQ.Using transmission electron microscopy,we observed that magnetosomes having 2-3 shapes were randomly distributed within this ciliate.Energydispersive X-ray spectroscopy and high-resolution transmission electron microscopy images of the magnetosomes were consistent with them being composed of magnetite.Magnetosomes having the same shape and mineral composition were also detected in MTB that occurred in the same environment as the ciliated MRP.Statistical analysis showed that the size and shape of the magnetosomes in the ciliated MRP were similar to those in MTB.The results suggest that this ciliated MRP can graze,ingest,and digest various types of MTB.It is certainly worth noting that this is the first record of MRPs in Asian aquatic sediment and suggesting they might be widely distributed.These results also support the assertion that MRPs probably contribute to the ecological cycles of iron,and expand possibilities for research into the mechanism of magnetoreception in eukaryotes.
基金Supported by the National Natural Science Foundation of China (No. 30770238)
文摘We examined the structure and spatial organization of ciliature base-associated microtubules （BAM） in three hypotrichous ciliates （Stylonychia mytilus, Pseudourostyla cristata, Euplotes woodruffi） in fluorescence microscopy. The results revealed that BAM, including the anterior （ALM）, posterior longitudinal microtubule （PLM） and the transverse microtubule （TM） bands, are composed of tubulin. The respective microtubular bands have cytoplasmic polarization patterns that are significantly asymmetric. The BAM of the midventral files in P. cristata appear cord-shaped compared with the ALM bands of transverse cirri in both S. mytilus and E. woodruffi, which extend to the left anterior side of the cell before converging. The TM bands of the left marginal cirri （MC） in S. rnytilus extend to the right side of the cell, while those of the right MC bands extend to the left. Our observations suggest that BAM traits are common in hypotrichous ciliates even though different species possess different microtubule arrangements related to the conserved cirral morphogenetic patterns in the respective species. The differing development of BAM in the three ciliate suggests that the microtubules may be conserved in different hypotrichs. We have also demonstrated that the BAM, which appear polar and asymmetric, are localized in specific cytoskeletal positions and extend in different orientations within the cortex to connect with other ciliature-associated structures and, thus, strengthen the cortex. These BAM features indicate that they are directly associated with cell motion.
基金This work was supported by the project of the National Natural Science Foundation of China(32030015)the Fundamental Research Funds for the Central Universities(862101013143,202141007).
文摘Chromosomes are well-organized carriers of genetic information in eukaryotes and are usually quite long,carrying hundreds and thousands of genes.Intriguingly,a clade of single-celled ciliates,Spirotrichea,feature nanochromosomes—also called“gene-sized chromosomes”.These chromosomes predominantly carry only one gene,flanked by short telomere sequences.However,the organization and copy number variation of the chromosomes in these highly fragmented genomes remain unexplored in many groups of Spirotrichea,including the marine Strombidium.Using deep genome sequencing,we assembled the macronuclear genome of Strombidium stylifer into more than 18,000 nanochromosomes(~2.4 Kb long on average).Our results show that S.stylifer occupies an intermediate position during the evolutionary history of Strombidium lineage and experienced significant expansions in several gene families related to guanyl ribonucleotide binding.Based on the nucleotide distribution bias analysis and conserved motifs search in non-genic regions,we found that the subtelomeric regions have a conserved adenine-thymine(AT)-rich sequence motif.We also found that the copy number of nanochromosomes lacks precise regulation.This work sheds light on the unique features of chromosome structure in eukaryotes with highly fragmented genomes and reveals that a rather specialized evolutionary strategy at the genomic level has resulted in great diversity within the ciliated lineages.
