The genus Cylindrotheca consists of a small group of marine diatoms with a few species described. Eleven isolates of diatoms identified as Cylindrotheca closterium morphologically were obtained from Jiaozhou Bay with ...The genus Cylindrotheca consists of a small group of marine diatoms with a few species described. Eleven isolates of diatoms identified as Cylindrotheca closterium morphologically were obtained from Jiaozhou Bay with their nuclear-encoded small-subunit ribosomal RNA (SSU rDNA) and chloroplast-encoded rbcL gene sequences determined in this study. Interestingly, very high sequence divergences of SSU rDNA and rbcL gene were found among these isolates, and numerous nucleotide variation of rbcL gene caused relatively few variation of deduced amino acid sequence. Phylogenetic analyses based on SSU rDNA and rbcL gene, respectively, grouped the isolates into 6 clades. Phylogenetic tree of SSU rDNA placed all the Cylindrotheca isolates together, separating them into two lineages clearly. Lineage I was composed of the eleven C. closterium isolates obtained in this study together with another C. closterium isolate, but some clades were not well supported. Lineage II contained two C. closterium isolates and one C. fusiformis isolate. Phylogenetic analysis of rbcL gene also separated the Cylindrotheca isolates into two well-defined lineages. The eleven C. closterium isolates formed a lineage and all clades were supported strongly. Statistical comparisons of SSU rDNA indicated that the average distance within lineageⅠwas significantly higher than that of other microalgae species (P < 0.01). These results suggested the existence of cryptic species within C. closterium.展开更多
Prostomates and haptorians are two basal groups of ciliates with limited morphological characteristics available for taxonomy. Morphologically, the structures used to identify prostomates and haptorians are similar or...Prostomates and haptorians are two basal groups of ciliates with limited morphological characteristics available for taxonomy. Morphologically, the structures used to identify prostomates and haptorians are similar or even identical, which generate heavy taxonomic and phylogenetic confusion. In present work, phylogenetic positions lineage of two rare genera, Plagiopogon and Askenasia, were investigated. Three genes including small subunit ribosomal RNA gene(hereafter SSU r DNA), internal transcribed spacer region(ITS region), and large subunit ribosomal RNA gene(LSU r DNA) were analyzed, 10 new sequences five species each. Our findings included 1) class Prostomatea and order Haptorida are multiphyletic; 2) it may not be appropriate to place order Cyclotrichiida in subclass Haptoria, and the systematic lineage of order Cyclotrichiida needs to be verified further; 3) genus Plagiopogon branches consistently within a clade covering most prostomes and is basal of clade Colepidae, implying its close lineage to Prostomatea; and 4) Askenasia is phylogenetically distant from the subclass Haptoria but close to classes Prostomatea, Plagiopylea and Oligohymenophorea. We supposed that the toxicyst of Askenasia may be close to taxa of prostomes instead of haptorians, and the dorsal brush is a more typical morphological characteristics of haptorians than toxicysts.展开更多
supported in part by grants from the Strategic Priority Research Program of Chinese Academy of Sciences （XDB15010103）;the National Natural Science Foundation of China （41201247）
Protists(microbial eukaryotes)are indispensable members of the marine microbial food web.In recent years,organisms living in the deep sea(>1000 m water depth)have increasingly become the focus of research;however,s...Protists(microbial eukaryotes)are indispensable members of the marine microbial food web.In recent years,organisms living in the deep sea(>1000 m water depth)have increasingly become the focus of research;however,studies on protistan assemblages are relatively scarce compared with their prokaryotic counterparts.In the present study,high-throughput sequencing of the hypervariable V9 region of the 18S rRNA gene was used to explore the community composition of protists in bathypelagic waters of the South China Sea.Based on the analysis of the alpha and beta diversities of 14 samples,we discovered:1、members belonging to Rhizaria,Alveolata,and Excavata were the dominant groups in terms of both relative sequence abundance and operational taxonomic unit(OTU)richness in all samples,although their relative contributions differed among different samples;2、cluster analysis showed that the distribution of protistan assemblages was related neither to the sampling location nor to the water depth,and other environmental factors might have caused the differences among the communities;3、phototrophs,including members of the Bacillariophyta,Bolidophyceae,Dictyochophyceae,Prasinophyceae,and Prymnesiophyceae,were detected in all samples,which indicated their contributions to the downward transportation via the biological pump and the potential presence of phagotrophy of these phototrophic cells in the deep ocean.展开更多
As one of the main groups of marine planktonic protozoa,oligotrich ciliates have shown a high biodiversity.Recently,a new aloricate oligotrich ciliate,Strombidium pseudorapulum sp.n.was isolated from coastal waters of...As one of the main groups of marine planktonic protozoa,oligotrich ciliates have shown a high biodiversity.Recently,a new aloricate oligotrich ciliate,Strombidium pseudorapulum sp.n.was isolated from coastal waters of southeast China.The living morphology and infraciliature of this species were studied using live cell observation and protargol impregnation.Strombidium pseudorapulum sp.n.differs from its congeners by having a radish-like body with a bumped anterior end and an elongated tail-like posterior end,possessing a red‘eyespot’in apical protrusion of cell,adoral zone of membranelles composed of 12–16 collar and 9–12 buccal membranelles,one spindle-shaped macronucleus,girdle kinety in anterior 2/5 of cell with 45–60 densely spaced dikinetids,and ventral kinety occupying about the posterior 1/3 of the cell with 16–19 dikinetids.Strombidium pseudorapulum sp.n.clusters together with those species having‘eyespot’in apical protrusion in the phylogenetic tree based on the small subunit rRNA gene sequence.It is a sister species of S.cuneiforme with 31 unmatched nucleotides between their SSU rRNA gene sequences.展开更多
To clarify the confusion surrounding species identification and state intraspecific variations, this research studied the morphological taxonomy of five species, Kentrophyllum cf. setigerum Petz et al., 1995; Zosterod...To clarify the confusion surrounding species identification and state intraspecific variations, this research studied the morphological taxonomy of five species, Kentrophyllum cf. setigerum Petz et al., 1995; Zosterodasys shumerica Aliev, 1990; Frontonia tchibisovae Burkovsky, 1970; Neourostylopsis orientalis Chen et al., 2013; and Apoholosticha cf. sinica Fan et al., 2014, which were collected from Chongming Island's marsh wetlands. Kentrophyllum cf. setigerum possesses less somatic kineties than K. setigerum(19–26 right and 18–25 left kineties vs 35–40 right and 30 left kineties). Whether Z. shumerica is identical to Z. transversa Foissner et al., 1994, which was presented in a previous report, was negated. The improved diagnosis for the species is provided. Frontonia tchibisovae was confirmed to have three or four micronuclei, and the number of kinetosome rows in its peniculus 3 varied between China and Russia populations. The new population of N. orientalis bears cortical granules, which differs from the original population that has an arrangement of rows across the dorsal bristles. For A. cf. sinica, there are colorless cortical granules on the ventral side of the new population, whereas in the previously reported populations bright orange, spherical granules were clustered around dorsal cilia. Additionally, we sequenced the small-subunit(SSU) rRNA genes of K. cf. setigerum, N. orientalis, and A. cf. Sinica, and compared the new and reported populations. For the first time, we also provide a species list, including 33 ciliates collected from the wetlands based on living observation and silver staining.展开更多
Species of the red algal order Acrochaetiales mostly inhabit marine environments,with only two freshwater taxa Audouinella and Ottia.A new genus and species are described for freshwater red alga Pauciramus yunnanensis...Species of the red algal order Acrochaetiales mostly inhabit marine environments,with only two freshwater taxa Audouinella and Ottia.A new genus and species are described for freshwater red alga Pauciramus yunnanensis from Ailao Mountain,Yunnan,China.It is closely related to Ottia and a new order Ottiales was proposed for these genera.Pauciramus has unique combination of morphological characteristics including the following:plants caespitose and densely pulvinate,slender uniseriate filaments with well-developed rhizoids,rarely branched,cylindrical vegetative cell with a single,ribbon-shaped and parietal chloroplast,reproduction by tetrasporangia,and dense sporangial branchlet only at the upper portion of filaments.Phylogenetic analysis of sequence data from the plastid ribulose-1,5-bisphosphate carboxylase-oxygenase large-subunit(rbc L),small subunit gene of the ribosomal cistron(SSU)and barcode region near the 5′end of the mitochondrial cytochrome oxidase subunit I(COI-5P)indicated that:the new taxon,P.yunnanensis,was in a well-supported clade with Ottia meiospora,and this clade was sister to order Palmariales and Acrochaetiales.To adhere to the principle of monophyly,a new freshwater order Ottiales including Ottia and Pauciramus is proposed.Despite the high sequence interspecific divergences and obvious morphological differences between genera Ottia and Pauciramus,seems impractical to establish a new family for a monospecific genus.Therefore,we temporarily classified Pauciramus into the family Ottiaceae,and made necessary revisions to the description to accommodate this genus.展开更多
基金This research was financially supported by an open project of The Key Laboratory of Mariculture of The Ministry of Education of China affiliated to 0cean umversity of China(200405)by the National Natural Science Foundation of China(30471318,40176028).
文摘The genus Cylindrotheca consists of a small group of marine diatoms with a few species described. Eleven isolates of diatoms identified as Cylindrotheca closterium morphologically were obtained from Jiaozhou Bay with their nuclear-encoded small-subunit ribosomal RNA (SSU rDNA) and chloroplast-encoded rbcL gene sequences determined in this study. Interestingly, very high sequence divergences of SSU rDNA and rbcL gene were found among these isolates, and numerous nucleotide variation of rbcL gene caused relatively few variation of deduced amino acid sequence. Phylogenetic analyses based on SSU rDNA and rbcL gene, respectively, grouped the isolates into 6 clades. Phylogenetic tree of SSU rDNA placed all the Cylindrotheca isolates together, separating them into two lineages clearly. Lineage I was composed of the eleven C. closterium isolates obtained in this study together with another C. closterium isolate, but some clades were not well supported. Lineage II contained two C. closterium isolates and one C. fusiformis isolate. Phylogenetic analysis of rbcL gene also separated the Cylindrotheca isolates into two well-defined lineages. The eleven C. closterium isolates formed a lineage and all clades were supported strongly. Statistical comparisons of SSU rDNA indicated that the average distance within lineageⅠwas significantly higher than that of other microalgae species (P < 0.01). These results suggested the existence of cryptic species within C. closterium.
基金supported by the National Natural Science Foundation of China(Nos.31222050,41376141,3112041,and 31471973)the international research projects from King Saud University(Nos.RGP-VPP-083,IRG14-22)
文摘Prostomates and haptorians are two basal groups of ciliates with limited morphological characteristics available for taxonomy. Morphologically, the structures used to identify prostomates and haptorians are similar or even identical, which generate heavy taxonomic and phylogenetic confusion. In present work, phylogenetic positions lineage of two rare genera, Plagiopogon and Askenasia, were investigated. Three genes including small subunit ribosomal RNA gene(hereafter SSU r DNA), internal transcribed spacer region(ITS region), and large subunit ribosomal RNA gene(LSU r DNA) were analyzed, 10 new sequences five species each. Our findings included 1) class Prostomatea and order Haptorida are multiphyletic; 2) it may not be appropriate to place order Cyclotrichiida in subclass Haptoria, and the systematic lineage of order Cyclotrichiida needs to be verified further; 3) genus Plagiopogon branches consistently within a clade covering most prostomes and is basal of clade Colepidae, implying its close lineage to Prostomatea; and 4) Askenasia is phylogenetically distant from the subclass Haptoria but close to classes Prostomatea, Plagiopylea and Oligohymenophorea. We supposed that the toxicyst of Askenasia may be close to taxa of prostomes instead of haptorians, and the dorsal brush is a more typical morphological characteristics of haptorians than toxicysts.
基金supported in part by grants from the Strategic Priority Research Program of Chinese Academy of Sciences (XDB15010103)the National Natural Science Foundation of China (41201247)
文摘supported in part by grants from the Strategic Priority Research Program of Chinese Academy of Sciences （XDB15010103）;the National Natural Science Foundation of China （41201247）
基金supported by the National Natural Science Foundation of China (Nos. 41876142, 91751207 and 41861144018)the Senior User Project of RV KEXUE (No. KEXUE2019 G08) funded by the Center for Ocean Mega-Science, Chinese Academy of Sciences
文摘Protists(microbial eukaryotes)are indispensable members of the marine microbial food web.In recent years,organisms living in the deep sea(>1000 m water depth)have increasingly become the focus of research;however,studies on protistan assemblages are relatively scarce compared with their prokaryotic counterparts.In the present study,high-throughput sequencing of the hypervariable V9 region of the 18S rRNA gene was used to explore the community composition of protists in bathypelagic waters of the South China Sea.Based on the analysis of the alpha and beta diversities of 14 samples,we discovered:1、members belonging to Rhizaria,Alveolata,and Excavata were the dominant groups in terms of both relative sequence abundance and operational taxonomic unit(OTU)richness in all samples,although their relative contributions differed among different samples;2、cluster analysis showed that the distribution of protistan assemblages was related neither to the sampling location nor to the water depth,and other environmental factors might have caused the differences among the communities;3、phototrophs,including members of the Bacillariophyta,Bolidophyceae,Dictyochophyceae,Prasinophyceae,and Prymnesiophyceae,were detected in all samples,which indicated their contributions to the downward transportation via the biological pump and the potential presence of phagotrophy of these phototrophic cells in the deep ocean.
基金the National Natural Science Foundation of China(No.31761133001)the Guangdong MEPP Fund(No.GDOE(2019)A23)+1 种基金the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.GML2019ZD0405)Innovation Academy of South China Sea Ecology and Environmental Engineering,Chinese Academy of Sciences(No.ISEE 2018PY01).
文摘As one of the main groups of marine planktonic protozoa,oligotrich ciliates have shown a high biodiversity.Recently,a new aloricate oligotrich ciliate,Strombidium pseudorapulum sp.n.was isolated from coastal waters of southeast China.The living morphology and infraciliature of this species were studied using live cell observation and protargol impregnation.Strombidium pseudorapulum sp.n.differs from its congeners by having a radish-like body with a bumped anterior end and an elongated tail-like posterior end,possessing a red‘eyespot’in apical protrusion of cell,adoral zone of membranelles composed of 12–16 collar and 9–12 buccal membranelles,one spindle-shaped macronucleus,girdle kinety in anterior 2/5 of cell with 45–60 densely spaced dikinetids,and ventral kinety occupying about the posterior 1/3 of the cell with 16–19 dikinetids.Strombidium pseudorapulum sp.n.clusters together with those species having‘eyespot’in apical protrusion in the phylogenetic tree based on the small subunit rRNA gene sequence.It is a sister species of S.cuneiforme with 31 unmatched nucleotides between their SSU rRNA gene sequences.
基金supported by the National Natural Science Foundation of China (Nos. 31572223, 41876151, 31601843)
文摘To clarify the confusion surrounding species identification and state intraspecific variations, this research studied the morphological taxonomy of five species, Kentrophyllum cf. setigerum Petz et al., 1995; Zosterodasys shumerica Aliev, 1990; Frontonia tchibisovae Burkovsky, 1970; Neourostylopsis orientalis Chen et al., 2013; and Apoholosticha cf. sinica Fan et al., 2014, which were collected from Chongming Island's marsh wetlands. Kentrophyllum cf. setigerum possesses less somatic kineties than K. setigerum(19–26 right and 18–25 left kineties vs 35–40 right and 30 left kineties). Whether Z. shumerica is identical to Z. transversa Foissner et al., 1994, which was presented in a previous report, was negated. The improved diagnosis for the species is provided. Frontonia tchibisovae was confirmed to have three or four micronuclei, and the number of kinetosome rows in its peniculus 3 varied between China and Russia populations. The new population of N. orientalis bears cortical granules, which differs from the original population that has an arrangement of rows across the dorsal bristles. For A. cf. sinica, there are colorless cortical granules on the ventral side of the new population, whereas in the previously reported populations bright orange, spherical granules were clustered around dorsal cilia. Additionally, we sequenced the small-subunit(SSU) rRNA genes of K. cf. setigerum, N. orientalis, and A. cf. Sinica, and compared the new and reported populations. For the first time, we also provide a species list, including 33 ciliates collected from the wetlands based on living observation and silver staining.
基金Supported by the National Natural Science Foundation of China (No.41871037 to Shulian XIE and No.31800172 to Fangru NAN)the Fund for Shanxi"1331 Project"
文摘Species of the red algal order Acrochaetiales mostly inhabit marine environments,with only two freshwater taxa Audouinella and Ottia.A new genus and species are described for freshwater red alga Pauciramus yunnanensis from Ailao Mountain,Yunnan,China.It is closely related to Ottia and a new order Ottiales was proposed for these genera.Pauciramus has unique combination of morphological characteristics including the following:plants caespitose and densely pulvinate,slender uniseriate filaments with well-developed rhizoids,rarely branched,cylindrical vegetative cell with a single,ribbon-shaped and parietal chloroplast,reproduction by tetrasporangia,and dense sporangial branchlet only at the upper portion of filaments.Phylogenetic analysis of sequence data from the plastid ribulose-1,5-bisphosphate carboxylase-oxygenase large-subunit(rbc L),small subunit gene of the ribosomal cistron(SSU)and barcode region near the 5′end of the mitochondrial cytochrome oxidase subunit I(COI-5P)indicated that:the new taxon,P.yunnanensis,was in a well-supported clade with Ottia meiospora,and this clade was sister to order Palmariales and Acrochaetiales.To adhere to the principle of monophyly,a new freshwater order Ottiales including Ottia and Pauciramus is proposed.Despite the high sequence interspecific divergences and obvious morphological differences between genera Ottia and Pauciramus,seems impractical to establish a new family for a monospecific genus.Therefore,we temporarily classified Pauciramus into the family Ottiaceae,and made necessary revisions to the description to accommodate this genus.
