Re-identifying Grateloupia yangjiangensis(Rhodophyta, Halymeniaceae) based on morphological observations, life history and rbcL sequence analyses

On the basis of morphological observations, life history and molecular phylogeny, Grateloupia yangjiangensis, which is similar to G. filicina, G. orientalis, G. catenata, and G. ramosissima in appearance, was re-examined. The results are as follows：（1） the auxiliary-cell ampullae of G. yangjiangensis were of Grateloupia type, thalli was fleshy and gelatinous in texture, and the erect axes were compressed; the cortex was 0.25–0.30 mm thick, consisting of five to seven outer layers, and there were five inner layers of triangular or stellate cells;（2） there was no filamentous stage in the development of the carpospores;（3） the ribulose-1,5-bisphosphate carboxylase/oxygenase gene（rbcL） sequence of four G. yangjiangensis examined showed that there was no intergeneric divergence among them, and for the phylogenetic tree, four sequences of G. yangjiangensis formed a single monophyletic subclade within the large Grateloupia clade of Halymeniaceae. In conclusion, G. yangjiangensis was a single species within the genus Grateloupia. This research provided criterion for identification and cultivation of G. yangjiangensis.

Bioactive extracts of red seaweeds Pterocladiella capillacea and Osmundaria obtusiloba(Floridophyceae:Rhodophyta) with antioxidant and bacterial agglutination potential

Objective:To evaluate the antioxidant,antibacterial and bacterial cell agglutination activities of the hexane(Hex) and 70%ethanol(70%EtOH) extracts of two species of red seaweeds Pterocladiella capillacea(P.capillacea) and Osmundaria obtusiloba.Methods:In vitro antioxidant activity was determined by DPPH radical scavenging assay,ferric-reducing antioxidant power assay,ferrous ion chelating assay,β-carotene bleaching assay and total phenolic content quantification.Antimicrobial activity was tested using the method of disc diffusion on Mueller-Hinton medium.The ability of algal extracts to agglutinate bacterial cells was also tested.Results:The 70%EtOH extract of the two algae showed the highest values of total phenolic content compared to the Hex extract.The results of DPPH for both extracts(Hex,70%EtOH) of Osmundaria obtusiloba(43.46%and 99.47%) were higher than those of P.capillacea(33.04%and 40.81%) at a concentration of 1 000 μg/mL.As for the ferrous ion chelating,there was an opposite behavior,extracts of P.capillacea had a higher activity.The extracts showed a low ferric-reducing antioxidant power,with optical density ranging from0.054 to 0.180.Antioxidant activities of all extracts evaluated for β-carotene bleaching were above 40%.There was no antibacterial activity against bacterial strains tested.However,the extracts of both species were able to agglutinate bacterial Gram positive cells of Staphylococcus aureus and Gram negative cells of Escherichia coli,multidrug-resistant Salmonella and Vibrio harveyi.Conclusions This is the first report of the interaction between these algal extracts,rich in natural compounds with antioxidant potential,and Gram positive and Gram negative bacterial cells.

Phylogenomic analysis of transcriptomic sequences of mitochondria and chloroplasts for marine red algae(Rhodophyta)in China

The chloroplast and mitochondrion of red algae （Phylum Rhodophyta） may have originated from different endosymbiosis. In this study, we carried out phylogenomic analysis to distinguish their evolutionary lin-eages by using red algal RNA-seq datasets of the 1 000 Plants （1KP） Project and publicly available complete genomes of mitochondria and chloroplasts of Rhodophyta. We have found that red algae were divided into three clades of orders, Florideophyceae, Bangiophyceae and Cyanidiophyceae. Taxonomy resolution for Class Florideophyceae showed that Order Gigartinales was close to Order Halymeniales, while Order Graci-lariales was in a clade of Order Ceramials. We confirmed Prionitis divaricata （Family Halymeniaceae） was closely related to the clade of Order Gracilariales, rather than to genus Grateloupia of Order Halymeniales as reported before. Furthermore, we found both mitochondrial and chloroplastic genes in Rhodophyta under negative selection （Ka/Ks〈1）, suggesting that red algae, as one primitive group of eukaryotic algae, might share joint evolutionary history with these two organelles for a long time, although we identified some dif-ferences in their phylogenetic trees. Our analysis provided the basic phylogenetic relationships of red algae, and demonstrated their potential ability to study endosymbiotic events.

STRUCTURAL STUDIES ON THE OLIGOMERS FROM THE POLYSACCHARIDE OF GRACILARIA TEXTORII (RHODOPHYTA) USING β-AGARASE AND 13C-NMR SPECTROSCOPY

The 60% ethanolic extract from Gracilaria textorii (Rhbdophyta) was degraded with B- agarase, and certain charged (sulfated) and neutral oligosaccharides were separated by using DEAE Sephadex A 25 and Bio- gel P6 , P2 chromatographic techniques . Some of the charged oligomers were verified to be neoagarotetraose - 63- sulfate ( DP2 ). neoagarohexaose- 63 】 65 - disulfate ( DP3 ) and neoagarooctaose- 63, 65, 67-trisulfate (DP4) by using 13C-and ’H-NMR spectroscopy . One neutral oligomer was assumed to be a mixture of methylated neoagarotetraoses (DP2 ) by 1H-NMR spectroscopy .These oligomers assigned by their chemical shifts may be used as the model compounds for the structural investigation of the agar- type sulfated polysaccharides using the B- agarase degradation method .

Laurencia nanhaiense sp.nov.,a new species of the genus Laurencia(Rhodomelaceae,Rhodophyta) from China

Laurencia nanhaiense sp. nov. （Rhodomelaceae, Rhodophyta） is described from Hainan and Guangdong Provinces, China. The new species clearly displays one of the defining features of the genus, viz. four periaxial cells per vegetative axial segment. It differs from other closely related species in having a combination of features such as terete axes from a basal system composed of a primary discoid holdfast and a secondary attachment to give rise to many short rhizoids, branching oppositely and alternately, irregularly tristichous or subverticillately polystichous, having more curve branches with very sparse, adventitious ultimate branchlets, non-projecting superficial cortical cells at the apices of ultimate branchlets, presence of longitudinally oriented secondary pit-connections between contiguous superficial cortical cells, absence of lenticular thickenings in the walls of medullary cells, parallel arrangement of tetrasporangia along the axis of stichidia, and presence of intercellular spaces between medullary cells.

A New Criterion for Distinguishing <i>Yendonia</i>Kylin and <i>Mikamiella</i>M.J. Wynne (Delesseriaceae, Rhodophyta)

An additional morphological criterion is presented to distinguish vegetative samples of the genera Yendonia and Mikamiella (Delesseriaceae, Rhodophyta). The undescribed earlier feature of Y. crassifolia is the presence of abundant lightrefracting cells in the tissues of the blades of both fertile and vegetative plants. This feature was never observed in Mikamiella, namely, in M. ruprechtiana. Additional data amending the description of the genus Yendonia are presented.

Codon Usage of Chloroplast Gene rbcL in Laurencia sensu lato(Rhodophyta)species

Recent advances in molecular biology make it possible to sequence not only genes or genomes,but also to understand codon dynamics.For the organelle genes of these organisms,a small set of preferred codons are used for encoding proteins.For the first time,this paper treats the divergence of synonymous codon usage and its bias in the rbcL gene within the Laurencia complex of red algae.We observed that the synonymous codon preference biases in rbcL are large and differ among species.A clear distinction in codon usage between genera is evident:the genera Dasya and Delesseria use a set that fluctuated between 53 and 58 codons.Whereas,in the genera Ceramium,Chondrophycus,Chlamydomonas,Chlorella,Laurencia s.s,Osmundea,and Palisada codon usage indicates a higher restriction fluctuating between 40 to 51 codons.Laurencia complex genera and other representative algae showed a defined composition pattern,with lower percentage values of NNC/G(7-24.9%).Dasya and Delesseria showed a selective pattern tendency because of high percentage values of NNC/G(54-55%).The estimated codon bias parameters were tested to infer systematic relationships and match suitable codons with the NNC/G codon percentages.Cluster analysis based on Codon Usage supports phylogenetic relationships between Chondrophycus,Palisada,Laurencia,Osmundea,and Yuzurua species.

An improved PCR method for direct identification of Porphyra(Bangiales,Rhodophyta) using conchocelis based on a RUBISCO intergenic spacer

An improved method of PCR in which the small segment of conchocelis is amplified directly without DNA extraction was used to amplify a RUBISCO intergenic spacer DNA fragment from nine species of red algal genus Porphyra(Bangiales,Rhodophyta),including Porphyra yezoensis(Jiangsu,China),P.haitanensis(Fujian,China),P.oligospermatangia(Qingdao,China),P.katadai(Qingdao,China),P.tenera(Qingdao,China),P.suborboculata(Fujian,China),P.pseudolinearis(Kogendo,Korea),P.linearis(Devon,England),and P.fallax(Seattle,USA).Standard PCR and the method developed here were both conducted using primers specific for the RUBISCO spacer region,after which the two PCR products were sequenced.The sequencing data of the amplicons obtained using both methods were identical,suggesting that the improved PCR method was functional.These findings indicate that the method developed here may be useful for the rapid identification of species of Porphyra in a germplasm bank.In addition,a phylogenetic tree was constructed using the RUBISCO spacer and partial rbcS sequence,and the results were in concordant with possible alternative phylogenies based on traditional morphological taxonomic characteristics,indicating that the RUBISCO spacer is a useful region for phylogenetic studies.

Formation and early development of tetraspores of Polysiphonia urceolata (Rhodomelaceae,Rhodophyta)

Polysiphonia urceolata is one type of potential commercial red seaweeds used for breeding and cultivation, because of its significant biochemical and biomedical application. However, the information of breeding and seedling incubation for cultivation is limited, especially the early development. In this study, tetrasporohyte and gametophyte of P. urceolata were taken as the study materials in Huiquan Bay, Qingdao, China. The cleaned and sterilized tetrasporophytes and gametophytes were pre-cultured in sterilized seawater, then nurtured at 18°C, 25 μmol photons m-2 s-1 in 12:12 h (light:dark) photoperiod. Continuous observation under microscope showed that the early development consists of bipolar division stage and seedling stage. In the division stage, tetraspores germinate into bipolar sporelings that further differentiate into a colorless rhizoidal portion and a lightly pigmented upright shoot. The lightly pigmented rhizoidal cell develops to a rhizoid and the larger pigmented cell transforms to an erect axis. In the seedling stage, several quasi-protuberances appear on the erect axis and form juvenile seedlings. The results demonstrate the culture of P. urceolata from tetraspores under laboratory conditions.

浙江南麂列岛有节珊瑚藻(红藻门Rhodophyta)的分类研究

利用冷冻切片技术,通过形态学和解剖学方法,对采自我国东海沿岸浙江南麂列岛的大型海洋红藻珊瑚藻目(Corallinales)的有节类群进行了分类学研究。经鉴定,共发现珊瑚藻目有节类群2属5种,分别为珊瑚藻科Corallinaceae叉节藻亚科Amphiroideae叉节藻属Amphiroa的带形叉节藻A.beauvoisii;珊瑚藻亚科Corallinoideae珊瑚藻属Corallina的鳞形珊瑚藻C.confusa、粗枝珊瑚藻C.crassisima、珊瑚藻C.officinalis和小珊瑚藻C.pilulifera。通过较为清晰的解剖学特征图片,对该5种有节珊瑚藻外部形态和内部特征进行了详细的比较与描述。结合近年来国际上有关上述部分物种的分类地位变化,对我国现存的带形叉节藻A.zanata、粗扁节藻Bossiella cretacea和大边孢藻Marginisporum crassissimum的归并问题展开了详细分析与讨论,以期促进对珊瑚藻目海藻分类学有更加深入的理解。

Induction and cultivation of cloned filaments of Polysiphonia urceolata(Rhodomelaceae,Rhodophyta)

A filamentous clone of Polysiphonia urceolata was regenerated from segments cut from the fronds of gametophytes. Unlike wild thalli with short virgate branchlets, the clone was filamentous with few branches. Many transparent trichoblasts arose from pericentral cells during the induction culture, but these were seldom observed during normal growth. The trichoblasts were uniseriate, often colorless, and formed lobed rhizoids rapidly when they came into contact with solid substrates. In addition to morphological characteristics, the photosynthetic properties and growth conditions of the clone differed from those of the mother plant. Cross-gradient light and temperature culture experiments revealed that the most favorable conditions for culture of the filamentous clone were 22°C and 95-120 μE/(m2-s) light intensity. The photosynthetic light saturation value for filaments was approx. 100 μE/(m2-s), which is far lower than that of wild thalli. These results could be used to develop techniques for mass cultures of P. urceolata in photobioreactors for production of seed stock or bioactive products.

Formation of primary pit connection during conchocelis phase of Porphyra yezoensis (Bangiophyceae, Rhodophyta)

The formation of pit connection during conchocelis phase of Porphyra yezoensis Ueda was observed and examined with transmission electron microscope (TEM) and epifluorence microscope. It is indicated that the pit connection was formed in late stage of conchocelis phase and the early stages of conchosporangial cell development, and disappeared in bispore stage. The pit connection contained a thin membrane layer at outer pit plug. Stained with 4’, 6’-diamidino-2-phenylidole dihydrochloride hydrate (DAPI), transferring of DNA or RNA between adjacent cells were observed in late stage of conchocelis development, it was deduced that pit connection might serve as a channel for signal transduction and ge- netic substance transportation in conchocelis phase.

Long interspersed elements in three species of Gracilaria (Gracilariaceae, Rhodophyta)

In order to find out whether long interspersed elements (LINEs) existed in macro-algae ge- nomes or not, we tested the LINE homologues in representative families (species): Gracilaria (G. eucheumoides Harv., G. tenuistipitata Chang et Xia, and G. textorii (Sur) De-Toni), Laminaria (L. longis- sima Miyabe and L. japonica Aresch.), and Ulva (U. lactuca L. and U. pertusa Kjellm.) during 2004 to 2005. Polymerase Chain Reaction (PCR) was carried out with degenerate oligonucleotide primers de- signed from LINEs of rice homologues and Cin4 of maize. Cloning and nucleotide sequencing of the PCR products revealed that 4 clones that derived from 3 species of Gracilaria have LINE homologues. The nucleotide sequences of the 4 LINE homologues diverged greatly, but the amino acid sequences deduced from them were relatively conserved. The endonuclease regions of the LINE homologues greatly di- verged from that of other plants, but they had closer phylogenetic relationship to Zepp elements in Chlor- ella sp., which indicated that sequence divergence by vertical transmission has been a major influence on the evolution of algal LINEs.

The Xiamaling oil shale generated through Rhodophyta over 800 Ma ago

A suit of oil shales, predominated by black argillaceous silicalite and finely laminated black-brown shale, has been discovered in a set of carbonaceous-siliceous mudstone formations (350 m in thickness) in the third member of Xiamaling Formation of the Upper Proterozoic Qingbaikou Series (900―873 MaBP), Xiahuayuan, Hebei Province, China. The oil shale, combustible with strong bitumen odour, has su- per-high TOC contents ranging from 21.4% to 22.9%, bitumen “A” contents from 0.58% to 0.88% and oil length from 5.29% to 10.57%. The ultrathin section observation of the shale and the identification of its kerogen demonstrate that its hydrocarbon-generative parent material is mainly benthonic Rhodophyta whose specific tetrasporangia are legible and abundant. It is rarely reported in the literature that such a hydrocarbon-generative parent material, composed mainly of Rhodophyta and with extraordinarily high contents of TOC and bitumen “A”, developed into a set of high-quality source rocks. The extracts of the oil shale are characteristic of richness in 17α(H)-diahopanes and n-alkyl tricyclic terpenoids but low in steranes. Such a biomarker feature is obviously different from that of the extracts from other Proterozoic marine carbonate source rocks of the studied area. Since the biological constitution of this oil shale is rather simple, it is clear that these biomarkers most likely represent to certain extent the specific mo- lecular constitutions of the benthonic Rhodophyta identified in the ultrathin sections of the samples. Studies on its lithologic association and depositional sequences suggest that this suit of the carbona- ceous-siliceous mudstone formation, which contains oil shales, was probably developed in an under- compensation deep-bay environment when a maximum transgression occurred during the formation of the third member of Xiamaling Formation. The high concentration of SiO2 in this organic-rich rock and the positive correlation between TOC and some trace elements such as P, Cu, Ni, W and Mo indicate that this suit of rocks was affected by activities of bottom thermal currents as deposited.

三叉仙菜中4种化学成分的分离鉴定

为了进一步提取三叉仙菜(Ceramium rubrum)生物活性成分的化学物质,对其进行了较为系统的化学成分研究。从三叉仙菜的乙醇提取物中,运用硅胶柱色谱和SephadexLH20凝胶柱色谱层析分离得到4个化合物,经1H NMR,13C NMR和MS波谱分析,确定其结构分别为(1)3,7,11,15-tetramethyl-hexadec-2-en-1-ol;(2)cholest-5-en-3-βol;(3)3-palmitoyloxy-propane-1,2-diol;(4)adenosine,这4个化合物均为首次从该科植物中分离得到。

抗病毒红藻多糖的提取与测定

从我国沿海红藻中提取的粗多糖，经ＤＥＡＥ－纤维素柱层析得到红藻多糖ＲＰ_１，实验证实有明显抗病毒作用。通过气相色谱、红外光谱、Ｙａｐｈｅ测定方法，证明红藻多糖ＲＰ_１含硫酸基是一种硫酸酯化多糖，其单糖组成为半乳糖和３，６－内醚半乳糖，定量分析含量分别为：半乳糖７０．０４％、３，６－内醚半乳糖９．５６％、硫酸基１７．３０％。

不同温度、光照强度和硝氮浓度下龙须菜对无机磷吸收的影响

龙须菜的细胞壁含有丰富的胶质成份,是琼胶生产的良好原料,在中国沿海已经形成了大规模的人工养殖。同时,随着中国近海富营养化现象的日趋严重,龙须菜的规模养殖被认为是缓解海水富营养化的一条有效途径。以探讨龙须菜的生物修复功能为目的,研究了龙须菜对无机磷吸收的基本特征以及不同温度、光照强度和硝氮浓度对其的影响。整个实验在实验室可控条件下进行,分别设置了3个不同温度:15、23和31℃;3个不同的光照强度:0、30和200μmol photons/(m2.s)和3个不同的硝氮浓度:0、30和200μmol/L,测定了在不同的条件下培养的龙须菜对无机磷吸收的动力学曲线。结果表明:龙须菜对无机磷的吸收动力学曲线符合典型的米氏方程特征,并且吸收能力随温度和硝氮浓度的升高而增大,吸收效率在较低温度(15℃)和接近自然海水的硝氮浓度条件(30μmol/L)下较高;而低光照强度下[30μmolphotons/(m2.s)]的吸收能力和吸收效率均高于黑暗和高光强条件[200μmol photons/(m2.s)]。由此可见,温度、光照强度及硝氮浓度等环境因子都影响龙须菜对无机磷的吸收特性,但是,其具体的机制仍需进一步深入研究。

红藻多糖抗AIDS病毒作用的体外实验研究

本文对红藻多糖提取物的抗ＡＩＤＳ病毒作用进行了体外实验研究．结果表明，红藻多糖（ＲＰ１、ＲＰ２）对ＢＩＶ病毒的生长具有明显的抑制作用，其抑制率分别为８５．９６％和８８．６５％，与临床批准使用的抗ＡＩＤＳ药物叠氮脱氧胸腺嘧啶（ＡＺＴ）［１］（８９．５２％）近似，证实了红藻多糖作为抗ＡＩＤＳ药物的可行性．

我国淡水红藻两新记录种

本文报道我国淡水红藻的两个新记录种,即弧形串珠藻Batrachospermum arcuatum Kylin emend.Vis et al.和细链珠藻Sirodotia tenuissima(Collins) Skuja ex Flint.标本均采自我国山西省。

中国海洋红藻门新分类系统

利用研究结果并参考文献资料,对我国海洋红藻门新的分类系统进行组织和完善,并阐述了各物种分布特征。我国海洋红藻门有2纲16目46科216属845种及其变种,在我国海藻三区的区系分布为黄渤海190种、东中国海134种和南中国海702种,四小区的区系分布为黄海西区190种、东海西区134种、南海北区246种和南海南区576种。