Morphogenesis and Molecular Phylogeny of a Marine Urostylid Ciliate Apokeronopsis wrighti(Protista, Ciliophora, Hypotrichia)

Hypotrichs are one of the highly differentiated ciliated lineages which play important roles in ecological, environmental,evolutionary and basic biological studies. In the present study, we investigated the living characteristics, infraciliature, nuclear apparatus, ontogenesis and phylogenetic position of a marine hypotrichous ciliate, Apokeronopsis wrighti Long et al., 2008, which was isolated from coastal waters in Shenzhen, China. The new isolate resembles the type population in terms of morphological characteristics, morphometrics, and SSU rRNA gene sequence that is with a 99.7% similarity. Ontogenesis of A. wrighti is characterized by oral primordium for the proter as well as marginal and dorsal kineties anlagen in both filial products formed de novo, and the cirral row arranged along the paroral and endoral arises from several anterior frontoventral-transverse cirral streaks. Phylogenetic analyses based on SSU and concatenated gene data suggest that five species of Apokeronopsis form a monophyletic clade, and the genus Apokeronopsis is closely related to Thigmokeronopsis and Metaurostylopsis.

Salinity Acclimation Induces Reduced Energy Metabolism,Osmotic Pressure Regulation and Transcriptional Reprogramming in Hypotrichida Ciliate Gastrostyla setifera

Coastal and estuarine protists are frequently exposed to salinity undulation.While the tolerance and stress responses of microalgae to salinity have been extensively studied,there have been scarce studies on the physiological response of heterotrophic protists to salinity stressing.In this study,we investigated the physiological response of the heterotrophic ciliate Gastrostyla setifera to a salinity of 3,via a transcriptomic approach.The first transcriptome of genus Gastrostyla was obtained utilizing a group of manually isolated ciliate individuals(cells)and RNA-seq technique.The completeness of the transcriptome was verified.Differentially expressed gene(DEG)analysis was performed among the transcriptomes of G.setifera acclimated in saline water(salinity 3)and those cultured in fresh water.The results demonstrated a significant alternation in gene transcription,in which the ciliate exhibits a transcripttomic acclimation in responding salinity stressing.The up-regulated DEGs were enriched in the pathways of cytoskeleton proteins,membrane trafficking,protein kinases and protein phosphatases.These may represent enhanced functions of ion transport,stress response and cell protections.Pathways involved in energy metabolism and biosynthesis were markedly down-regulated,reflecting decreased cell activity.Particularly,we detected significantly down-regulated genes involved in several pathways of amino acid catabolism,which may lead to accumulation of amino acids in the ciliate cell.Amino acid could act as compatible solutes in the cytoplasm to maintain the osmotic balance in saline water.Overall,this work is an initial exploration to the molecular basis of the heterotrophic protist responding to salinity stressing.The result sheds light on the mechanisms of enhancement of cell protection,reduction of cell activity,and osmotic pressure regulation in ciliates acclimated to salinity.

Multi-gene-based investigation on the molecular phylogeny of the hypotrichous family Strongylidiidae(Protista,Ciliophora),with notes on the ontogeny of a new genus and new species

Ciliates in the subclass Hypotrichia have long been difficult to classify as they are one of the most polymorphic and highly differentiated groups,leading to their systematics remaining unresolved.Phylogenetic relationships within the hypotrich family Strongylidiidae have been ambiguous due to discordance between the morphological and genetic data.In this study,a new strongylidiid genus Heterouroleptus is established,mainly based on the novel mode of origin of the ventral cirral rows:left ventral cirral row(LVR)originates from frontal-ventral-transverse cirral anlagen(FVTA)Ⅲ(anterior portion),IV(middle portion),and V(rear portion);right ventral cirral row comes from the entire FVTA VI.A new species,Hetero-uroleptus weishanensis gen.nov.,sp.nov.,is investigated along with the morphometric and molecular data from a population of Strongylidium wuhanense.Eight new sequences and nuclear gene markers(single-gene and multi-gene)are provided to analyze the phylogenetic relationships of strongylidiids,with the COI gene utilized to uncover further genetic information at species level and below.The results reveal that:(1)Strongylidiidae is monophyletic and has a close relationship with Dorsomarginalia;(2)Heterouroleptus gen.nov.forms a clade that is sister to all the other strongylidiids;(3)Hemiamphisiella Foissner,1988 and Pseudouroleptus Hemberger,1985 should not be synonyms,and both genera should be subdivided due to their variable morphological characteristics;(4)LVR originating from three anlagen is a plesiomorphy of Strongylidiidae.The discovery of the origin of the LVR not only contributes to the establishment of the genus Heterouroleptus,but also helps to improve the diagnosis of the family Strongylidiidae.

Malignant transformation of pulmonary bronchiolar adenoma into mucinous adenocarcinoma:A case report

BACKGROUND Bronchiolar adenoma(BA)and ciliated muconodular papillary tumor are rare tumors that have bilayered cell proliferation and continuous expression of p40 and CK5/6 in the basal cell layer.Diagnosis is difficult because of the limited knowledge of these tumors and their morphological similarities to malignant tumors,including invasive mucinous adenocarcinoma,especially based on the histopathology of intraoperative frozen sections.These tumors are now considered to be benign neoplasms,with malignant transformation reported in only a few cases.CASE SUMMARY A 57-year-old woman presented with a 17.0 mm×7.0 mm nodule in the lower lobe of the left lung.Hematoxylin-eosin staining and immunohistochemistry of a surgical specimen were performed.The tumor consisted of a BA area and a mucinous adenocarcinoma(MA)area.In the BA area,the tumor had a bilayered structure of luminal cells and basal cells.The basal cells were positive for CK5/6 and p40,but the MA area was negative for these biomarkers.The Ki-67 proliferation index was low(1%-2%).The patient was diagnosed with BA accompanied by MA,and had a favorable outcome.CONCLUSION The present study indicated that BA may be carcinogenic,and suggests that clinicians should be aware of its potential for malignant transformation.

Cultivation Density of Toona ciliate

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.

Tissue Culture of Toona ciliata

In this study, a screening experiment was carried out among MS, WPM, DCR, MT, B5 and N6. The results showed that for proliferation culture of Toona ciliate, the optimum basic medium was WPM, and the optimum medium was WPM ＋ 6-BA 0.5 mg/L ＋ IBA 0.05 mg/L. The proliferation coefficient reached 4.29. The optimum rooting culture medium was 1/2 MS ＋ IBA 0.5 mg/L ＋ NAA 0.5 mg/L with rooting rate of 100%. In the optimum rooting ＇culture medium, the roots of T. ciliate developed neatly, and the seedlings grew well.

Molecular diversity and biogeography of benthic ciliates in the Bohai Sea and Yellow Sea

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.

Spatiotemporal variation in community structure of marine benthic ciliates in the Yellow Sea during and after macroalgal and giant jellyfish blooms

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.

Reevaluation of cortical developmental patterns in Euplotes(s.l.), including a morphogenetic redescription of E.charon (Protozoa,Ciliophora,Euplotida)

We documented the pattern of cell development in Euplotes charon. The ontogenesis of this species was similar to many of its congeners, except for the formation of the caudal cirri. In E. Charon, a caudal cirrus is formed posterior to each of the rightmost two or three dorsal kinety anlage in the proter, and the second rightmost dorsal kinety in the opisthe. In addition, two caudal cirri are formed posterior to the rightmost dorsal kinety in the opisthe. This pattern of development represents a completely new type. Based on our evaluation, and in comparison with previous studies, we also conclude that the pattern of cell development is variable among species in the Euplotes genera. The variation is particularly evident during the formation of frontoventral and caudal cirri. Based on the segmentation pattern of frontal-midventral transverse cirral anlagen, cirri reduction, and migration of frontoventral cirri, we identified five types: the affinis-type, the eurystomus-type, the charon-type, the raikovi-type and orientalis-type. Euplotes (s. l.) can also be divided into three types based on the formation of caudal cirri: focardii-type, vannus-type and charon-type. Indeed, we conclude that the number (one or two) of marginal cirri should be given as much consideration as the genetic separation. Given this, we reassessed the validity of using genetic separation to classify the group. Generally, the morphogenetic data disagreed with the molecular data (SSrRNA gene sequences). Given these discrepancies, it is too early to draw conclusions on the systematic arrangement of this species-rich taxon.

Tolerance of ciliated protozoan Paramecium bursaria (Protozoa, Ciliophora) to ammonia and nitrites

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.

Latitudinal changes (6°S-20°N) of summer ciliate abundance and species compositions in surface waters 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.

Marine ciliate community in relation to eutrophication of coastal waters in the Yellow Sea

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.

Spatiotemporal distribution of protozooplankton and copepod nauplii in relation to the occurrence of giant jellyfish in the Yellow Sea

The occurrence of the giant jellyfish, Nemopilema nomurai, has been a frequent phenomenon in the Yellow Sea. However, the relationship between the giant jellyfish and protozoa, in particular ciliates, remains largely unknown. We investigated the distribution of nanoflagellates, ciliates, Noctiluca scintillans, and copepod nauplii along the transect 33~N in the Yellow Sea in June and August, 2012, during an occurrence of the giant jellyfish, and in October of that year when the jellyfish was absent. The organisms studied were mainly concentrated in the surface waters in summer, while in autumn they were evenly distributed in the water column. Nanoflagellate, ciliate, and copepod nauplii biomasses increased from early June to August along with jellyfish growth, the first two decreased in October, while N. scintillans biomass peaked in early June to 3 571 pg C/L and decreased in August and October. In summer, ciliate biomass greatly exceeded that of copepod nauplii （4.61-15.04 ~tg C/L vs. 0.34-0.89 pg C/L）. Ciliate production was even more important than biomass, ranging from 6.59 to 34.19 ~tg C/（L.d） in summer. Our data suggest a tight and positive association among the nano-, micro-, and meso-zooplankton in the study area. Statistical analysis revealed that the abundance and total production of ciliate as well as loricate ciliate biomass were positively correlated with giant jellyfish biomass, indicating a possible predator-prey relationship between ciliates and giant jellyfish. This is in contrast to a previous study, which reported a significant reduction in ciliate standing crops due to the mass occurrence ofN. nomurai in summer. Our study indicates that, with its high biomass and, in particular, high production ciliates might support the mass occurrence of giant jellyfish.

Difference of planktonic ciliate communities of the tropical West Pacific, the Bering Sea and the Arctic Ocean

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.

Composition and Distribution of Planktonic Ciliates in the Southern South China Sea During Late Summer： Comparison Between Surface and 75 m Deep Layer

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.

Population dynamics of marine ciliate Euplotes vannus (Protozoa, Ciliophora) in different artificial seawaters

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.

Notes on Two Marine Ciliates from the Yellow Sea,China:Placus salinus and Strombidium apolatum(Protozoa,Ciliophora)

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.

Complementary DNA sequencing (cDNA): an eff ective approach for assessing the diversity and distribution of marine benthic ciliates along hydrographic gradients

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.

SHORT TIME DYNAMICS OF CILIATE ABUNDANCE IN THE BOHAI SEA (CHINA)

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.

Phylogenetic relationships within the genus Aspidisca(Protozoa,Ciliophora,Euplotida) revealed by ITS1-5.8S-ITS2 region sequences

Abstract The internal transcribed spacer regions （ITS1 and ITS2） and 5.8S rRNA genes were sequenced in six populations of four Aspidisca species, namely A. leptaspis, A. orthopogon, A. rnagna and A. aculeata. Phylogenetic trees were constructed by means of Bayesian inference （BI）, Maximum Parsimony （MP）, Neighbor-Joining （NJ）, and Maximum Likelihood （ML） to assess the inter- and intra-species relationships within the genus Aspidisca. All trees show similar topologies with stable supports and indicate that： （1） four well known groups, i.e., Oligotrichia, Stichotrichia, Choreotrichia and Hypotrichia, are distinctly outlined within the class Spirotrichea, and all are monophyletic other than Hypotrichia; （2） members of Aspidisca can be distinguished well, based on the ITSI-5.SS-ITS2 region sequences, and A. leptaspis and A. magna shared a closer relationship than other species; （3） Aspidisca and Euplotes branch early in the subclass Hypotrichia. To compare the phylogenetic relationships based on different genes, SSU rRNA trees were also constructed with nearly the same species inclusion, which revealed different topologies of inter-species, inter-genera and inter-subclasses.