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Shaojun Pang - One of the best experts on this subject based on the ideXlab platform.
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chloroplast genome of sargassum horneri Sargassaceae phaeophyceae comparative chloroplast genomics of brown algae
Journal of Applied Phycology, 2016Co-Authors: Shaojun PangAbstract:Sargassum horneri (Turner) C. Agardh is an important canopy-forming seaweed native to the northwestern Pacific coast growing in the upper sublittoral zone. In this study, the chloroplast genome of S. horneri was fully sequenced and compared with three other brown algal chloroplast genomes. The S. horneri chloroplast genome is 124,068 bp in size with an inverted repeat of 5436 bp and is slightly smaller than the other three brown algal chloroplast DNAs (cpDNAs). It contains 173 genes, including 6 ribosomal RNA (rRNA) genes, 28 transfer RNA (tRNA) genes, and 139 protein-coding genes (PCGs). The coding sequence constitutes 86.32 % of the S. horneri cpDNA. The total spacer size was found to be reduced to 16,967 bp with an average length of 101.0 bp, which makes the S. horneri cpDNA more compact than the other three brown algal cpDNAs. Sixteen small inverted and nine tandem repeats were detected in S. horneri chloroplast genomes. Two introns in trnL2 and trnW genes were identified with the size of 209 and 90 bp, respectively. Its gene content and order are identical to those of Fucus vesiculosus cpDNA, indicating that the chloroplast genome organization at the level of the order Fucales is highly conserved.
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complete mitochondrial genome of the invasive brown alga sargassum muticum Sargassaceae phaeophyceae
Mitochondrial DNA, 2016Co-Authors: Shaojun PangAbstract:Sargassum muticum (Yendo) Fensholt is an invasive canopy-forming brown alga, expanding its presence from Northeast Asia to North America and Europe. The complete mitochondrial genome of S. muticum is characterized as a circular molecule of 34,720bp. The overall AT content of S. muticum mitogenome is 63.41%. This mitogenome contains 65 genes typically found in brown algae, including 3 ribosomal RNA genes, 25 transfer RNA genes, 35 protein-coding genes, and 2 conserved open reading frames (ORFs). The gene order of mitogenome for S. muticum is identical to that for Sargassum horneri, Fucus vesiculosus and Desmarestia viridis. Phylogenetic analyses based on 35 protein-coding genes reveal that S. muticum has a close evolutionary relationship with S. horneri and a distant relationship with Dictyota dichotoma, supporting current taxonomic systems. The present investigation provides new molecular data for studies of S. muticum population diversity as well as comparative genomics in the Phaeophyceae.
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complete mitochondrial genome of the brown alga sargassum hemiphyllum Sargassaceae phaeophyceae comparative analyses
Mitochondrial DNA, 2016Co-Authors: Shaojun Pang, Weizhou ChenAbstract:Sargassum hemiphyllum (Turner) C. Agardh is a common low intertidal brown alga in the northwestern Pacific, and two varieties (var. chinense and var. hemiphyllum) of this alga have been determined based on morphological and molecular data. In this study, we present the complete mitochondrial genome of S. hemiphyllum var. chinense. The circular-mapping S. hemiphyllum mitogenome of 34,686bp has an overall A+T content of 63.43%, and contains 65 densely packed genes. The total intergenic spacer regions are 1597bp, constituting 4.60% of the mitogenome. The gene content and genome organization of S. hemiphyllum are identical to that of other reported Sargassum species. The identity comparison of overall mitogenome sequences and phylogenomic analyses indicate that S. hemiphyllum has a closer evolutionary relationship with Sargassum muticum than other Sargassum species analyzed. The present mitogenomic data provide a powerful tool for definition of varieties and studies of population structure in S. hemiphyllum.
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mitochondrial genome of turbinaria ornata Sargassaceae phaeophyceae comparative mitogenomics of brown algae
Current Genetics, 2015Co-Authors: Shaojun PangAbstract:Turbinaria ornata (Turner) J. Agardh is a perennial brown alga native to coral reef ecosystems of tropical areas of the Pacific and Indian Ocean. Very little is known about its organellar genome structure. In the present work, the complete mitochondrial genome sequence of T. ornata was determined and compared with other reported brown algal mtDNAs. The circular mitogenome of 34,981 bp contains a basic set of 65 mitochondrial genes. The structure and organization of T. ornata mitogenome is very similar to Sargassum species. Turbinaria ornata genes overlap by a total of 164 bp in 12 different locations from 1 to 66 bp, and the non-coding sequences are 1872 bp, constituting approximate 5.35 % of the genome. The total spacer size has positive correlation with the brown algal mitogenome size with the correlation coefficient of 0.7972. Several regions displaying greater inconsistency (rnl-trnK spacer, cox2 gene, cox3-atp6 spacer, rps14-rns middle region and trnP-rnl spacer) have been identified in brown algal mtDNAs. The observed uncertainty regarding the position and support values of some branches might be closely associated with the heterogeneity of evolutionary rate.
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complete mitochondrial genome of the brown alga sargassum horneri Sargassaceae phaeophyceae genome organization and phylogenetic analyses
Journal of Applied Phycology, 2015Co-Authors: Shaojun Pang, Xia Li, Jing LiAbstract:The genetics and molecular biology of the ecolog- ically important brown alga, Sargassum horneri (Turner) C. Agardh, are poorly known. In this investigation, the complete nucleotide sequence of the mitochondrial (mt) genome of S. horneri was determined using long PCR and primer walk- ing techniques. The mt genome is 34,606 bp in length and contains 3 ribosomal RNA genes, 25 transfer RNA genes, 35 protein-coding genes, and 2 open reading frames (ORFs). The overall AT content of the genome is 63.84 %, and the intergenic spacers constitute only 4.29 %. The genome orga- nization of S. horneri mitochondrial DNA (mtDNA) is very similar to Fucus vesiculosus except that the counterparts of one putative tRNA Tyr gene and ORF379 in Fucus were miss- ing from S. horneri mtDNA. Phylogenetic analyses based on 3 ribosomal RNA genes and 35 protein-coding genes suggest that S. horneri has a closer relationship with F. vesiculosus than other analyzed brown algae. Sargassum horneri is the first species of Sargassaceae to haveits mitochondrial genome sequenced. This will provide useful information on both pop- ulation genetics and molecular evolution of the related species.
Kunshan Gao - One of the best experts on this subject based on the ideXlab platform.
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seasonal pattern of reproduction of hizikia fusiformis Sargassaceae phaeophyta from nanao island shantou china
Journal of Applied Phycology, 2006Co-Authors: Dinghui Zou, Kunshan Gao, Zuoxi RuanAbstract:The maturation pattern of sexual reproduction in Hizikia fusiformis (Harvey) Okamura (Sargassaceae, Phaeaophyta) was examined in 2003 at Yunao Bay, Nanao Island, Shantou, China. Maturation began in mid-April (seawater temperature 19-21 degrees C), reached the peak in mid-May (maturation rate ca. 70%, and seawater temperature 23.5-25 degrees C) and finished in late-June (seawater temperature 27.5-30 degrees C). The Hizikia plants continued to gain the length from the beginning of maturation season to reach a maximum mean length of 34.8 cm in mid-May, after which the mean length was reduced drastically due to the senescence and rupture of the larger plants in size. The major portion of the mature plants belonged to the larger plants between April and May, but to the smaller ones in June. It is suggested that the plant must achieve a critical size before reproductive maturation occurred. There was a positive relationship between the number of receptacles (NR), as well as the reproductive allocation (RA), and the plant size of Hizikia population, with the recorded maximum values of NR and RA being 1220 and 64.3% respectively, for a single plant.
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photosynthetic characteristics of the economic brown seaweed hizikia fusiforme Sargassaceae phaeophyta with special reference to its leaf and receptacle
Journal of Applied Phycology, 2005Co-Authors: Dinghui Zou, Kunshan GaoAbstract:Photosynthetic responses to irradiance and temperature of "leaves" and receptacles were compared in February ( vegetative stage) and May ( reproductive stage) in the seaweed, Hizikia fusiforme ( Harvey) Okamura (Sargassaceae, Phaeophyta) from Nanao Island, Shantou, China. Irradiance-saturated photosynthesis (P-max) was significantly higher in receptacles than in "leaves" on a fresh weight basis, and that of "leaves" was greater in May than in February at ambient seawater temperatures. The optimum temperature for P-max was 30 degrees C for both "leaves" and receptacles, being 5 - 10 degrees C higher than the ambient seawater temperature. The apparent photosynthetic efficiencies were greater in receptacles than in "leaves" within the tested temperature range of 10 - 40 degrees C. The irradiance for saturating photosynthesis for both "leaves" and receptacles was temperature-dependent, with the highest values ( about 200 mu mol photons m(-2) s(-1)) at 30 degrees C.
Thierry Thibaut - One of the best experts on this subject based on the ideXlab platform.
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First characterization of eight polymorphic microsatellites for Cystoseira amentacea var. stricta (Fucales, Sargassaceae)
Conservation Genetics Resources, 2012Co-Authors: P. Robvieux, Thierry Thibaut, A. Meinesz, Julie Videment, Cecile Ribout, Didier Forcioli, L. BottinAbstract:First characterization of eight polymorphic microsatellites for Cystoseira amentacea var. stricta (Fucales, Sargassaceae)
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First characterization of eight polymorphic microsatellites for Cystoseira amentacea var. stricta (Fucales, Sargassaceae)
Conservation Genetics Resources, 2012Co-Authors: P. Robvieux, Thierry Thibaut, A. Meinesz, Julie Videment, Cecile Ribout, Didier Forcioli, L. BottinAbstract:Cystoseira amentacea var. stricta (Sargassaceae) is an endemic alga of the Mediterranean Sea. It grows in the upper sublittoral wave-exposed zone and is submitted to various anthropogenic pressures resulting in population fragmentation. In order to assess the genetic diversity and structure of these populations, we developed eight microsatellite markers and validated them on 57 individuals from two populations. With 4–9 alleles per locus, the observed heterozygosity varied between 0.033 and 0.852. We tested cross-amplification of the eight primers on Cystoseira mediterranea, and it was successful for seven of these primers.
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DNA sequence data demonstrate the polyphyly of the genus cystoseira and other Sargassaceae genera (Phaeophyceae)
Journal of Phycology, 2010Co-Authors: Stefano G A Draisma, Enric Ballesteros, Florence Rousseau, Thierry ThibautAbstract:Phylogenetic relationships in the Sargassaceae were explored using three DNA markers, and the monophyly of its genera was challenged. Nineteen out of 24 currently recognized genera were sampled, representing 63 species. The variable mt23S-tRNA Val intergenic spacer could only be aligned within genera and could not be used to infer intergeneric relationships. The partial mt23S was also useful to delineate genera and was alignable at the family level but provided few informative characters. Analysis of mt23S DNA sequences together with chloroplast-encoded psbA sequences resulted in a better resolved phylogeny. Hormophysa was the first genus to branch off within the Sargassaceae, followed by Myriodesma; then the three genera Caulocystis, Carpoglossum, and Scaberia in unresolved order; and then Acrocarpia. The other taxa studied here were divided over three major clades, but there was no branch support for the monophyly of two of these. The genera Bifurcaria, Cystoseira, Halidrys, and Sargassum appeared polyphyletic. The following taxonomic changes are proposed: a new genus Brassicophycus for Bifurcaria brassicaeformis (Kutzing) E. S. Barton; reinstatement of the genus Sargassopsis for Sargassum decurrens (R. Brown ex Turner) C. Agardh; reinstatement of the genus Sirophysalis for Indo-Pacific Cystoseira trinodis (Forsskal) C. Agardh; reinstatement of the genus Polycladia for the western Indian Ocean species Cystoseira indica (Thivy et Doshi) Mairh, Cystoseira myrica (S. G. Gmelin) C. Agardh, and Acystis heinii Schiffner; and reinstatement of the genus Stephanocystis for the North Pacific Cystoseira species and Halidrys dioica N. L. Gardner. The European Cystoseira species should be split into three genera, but no name changes are proposed yet, because diagnostic characters were found only for the clade including the type species. Some evolutionary trends could be discerned from the mt23S + psbA phylogeny.
Dinghui Zou - One of the best experts on this subject based on the ideXlab platform.
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growth and photosynthesis in seedlings of hizikia fusiformis harvey okamura Sargassaceae phaeophyta cultured at two different temperatures
Journal of Applied Phycology, 2012Co-Authors: Dinghui Zou, Shuxia LiuAbstract:This study examined temperature acclimation, growth, and photosynthetic characteristics of the zygote-derived seedlings of Hizikia fusiformis (Harvey) Okamura (Sargassaceae). The seedlings were cultured at 15°C or 25°C for 4 weeks. The average relative growth rate was significantly higher in seedlings acclimated at 25°C. The photosynthetic rate measured at 15°C was much higher in seedlings grown at 15°C than those grown at 25°C, indicating photosynthetic acclimation to a lower temperature. At 35°C, the photosynthetic rate of 15°C-grown seedlings was drastically decreased, whereas that of 25°C-grown seedlings was significantly increased. The maximum relative electron transport rate (rETRmax) measured at the respective growth temperature was significantly higher in seedlings grown at 25°C than at 15°C. At a measuring temperature of 35°C, the rETRmax in both 15°C- and 25°C-grown seedlings were considerably reduced with regard to those measured at 15°C or 25°C. Our results suggested that, compared with the seedlings grown at 25°C, those acclimated at a lower temperature could be disadvantaged under adverse conditions such as increased temperatures.
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seasonal pattern of reproduction of hizikia fusiformis Sargassaceae phaeophyta from nanao island shantou china
Journal of Applied Phycology, 2006Co-Authors: Dinghui Zou, Kunshan Gao, Zuoxi RuanAbstract:The maturation pattern of sexual reproduction in Hizikia fusiformis (Harvey) Okamura (Sargassaceae, Phaeaophyta) was examined in 2003 at Yunao Bay, Nanao Island, Shantou, China. Maturation began in mid-April (seawater temperature 19-21 degrees C), reached the peak in mid-May (maturation rate ca. 70%, and seawater temperature 23.5-25 degrees C) and finished in late-June (seawater temperature 27.5-30 degrees C). The Hizikia plants continued to gain the length from the beginning of maturation season to reach a maximum mean length of 34.8 cm in mid-May, after which the mean length was reduced drastically due to the senescence and rupture of the larger plants in size. The major portion of the mature plants belonged to the larger plants between April and May, but to the smaller ones in June. It is suggested that the plant must achieve a critical size before reproductive maturation occurred. There was a positive relationship between the number of receptacles (NR), as well as the reproductive allocation (RA), and the plant size of Hizikia population, with the recorded maximum values of NR and RA being 1220 and 64.3% respectively, for a single plant.
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photosynthetic characteristics of the economic brown seaweed hizikia fusiforme Sargassaceae phaeophyta with special reference to its leaf and receptacle
Journal of Applied Phycology, 2005Co-Authors: Dinghui Zou, Kunshan GaoAbstract:Photosynthetic responses to irradiance and temperature of "leaves" and receptacles were compared in February ( vegetative stage) and May ( reproductive stage) in the seaweed, Hizikia fusiforme ( Harvey) Okamura (Sargassaceae, Phaeophyta) from Nanao Island, Shantou, China. Irradiance-saturated photosynthesis (P-max) was significantly higher in receptacles than in "leaves" on a fresh weight basis, and that of "leaves" was greater in May than in February at ambient seawater temperatures. The optimum temperature for P-max was 30 degrees C for both "leaves" and receptacles, being 5 - 10 degrees C higher than the ambient seawater temperature. The apparent photosynthetic efficiencies were greater in receptacles than in "leaves" within the tested temperature range of 10 - 40 degrees C. The irradiance for saturating photosynthesis for both "leaves" and receptacles was temperature-dependent, with the highest values ( about 200 mu mol photons m(-2) s(-1)) at 30 degrees C.
Anatolii I Usov - One of the best experts on this subject based on the ideXlab platform.
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a sulfated galactofucan from the brown alga hormophysa cuneiformis fucales Sargassaceae
Carbohydrate Research, 2018Co-Authors: Maria I Bilan, Alexander S Shashkov, Nikolay E Nifantiev, Nadezhda E Ustyuzhanina, Thi Thu Thuy Thanh, Minh Ly Bui, Thi Thanh Van Tran, Van Nguyen Bui, Anatolii I UsovAbstract:The brown alga Hormophysa cuneiformis collected from the coastal waters of Vietnam was used to isolate a mixture of sulfated polysaccharides FHC, which was fractionated further by anion-exchange chromatography on DEAE-Sephacel. The main fraction F3 eluted with 1.5 M NaCl contained essentially l-fucose, d-galactose and sulfate and has very complex NMR spectra. Desulfation to obtain F3deS followed by Smith degradation to obtain F3deS-Sm was used to simplify the structure of F3, and all these preparations were characterized by methylation analysis and NMR spectra. A linear (1 → 3)-linked backbone built up of α-l-fucopyranose residues was identified as the main structural motif of molecules. Some fucose residues attached to position 4 of its 3-linked neighbor were found as branches. Galactose residues having both α- and β-configurations were found mostly at the periphery of molecules. They are present as (1 → 6)-linked disaccharide of two β-d-Galp attached to position 4 of the backbone or as single α-d-Galp attached to the same position. Sulfate groups in F3 may probably occupy any positions of the molecule. F3 acts as anticoagulant and is about half as active as the standard low-molecular mass heparin (enoxaparin). FHC was practically inactive in cytotoxicity test against six human cancer cell lines.
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sulfated polysaccharides of the vietnamese brown alga sargassum aquifolium fucales Sargassaceae
Carbohydrate Research, 2017Co-Authors: Maria I Bilan, Alexander S Shashkov, Nadezhda E Ustyuzhanina, Thi Thu Thuy Thanh, Minh Ly Bui, Thi Thanh Van Tran, Van Nguyen Bui, Anatolii I UsovAbstract:A fucoidan preparation named FSA was isolated from the brown alga Sargassum aquifolium collected from the coastal waters of Vietnam. l-Fucose, d-galactose, d-mannose, d-glucuronic acid, d-xylose, and sulfate were found to be the main constituents of FSA. The preparation was fractionated by anion-exchange chromatography on DEAE-Sephacel eluted stepwise with 0.5, 1.0, 1.5, and 2.0 M NaCl to give four fractions differing in monosaccharide composition and degree of sulfation. Their NMR spectra were too complex to be completely interpreted. Fractions 1.0 M and 1.5 M were analyzed by methylation before and after desulfation. In addition, desulfated 1.0 M was fractionated by anion-exchange chromatography into six fractions according to the uronic acid content. They were characterized by methylation and NMR spectral data, and three structurally different polysaccharides were identified. One of them has a core of alternating 2-linked α-d-Manp and 4-linked β-d-GlcpA residues, about a half of the former bearing single α-l-Fucp or β-d-Xylp at position 3. The second polymer is a (1 → 3)-β-d-glucopyranuronan partially substituted with single β-d-Xylp or single α-l-Fucp at position 4. The third polysaccharide is a xylo(fuco)galactan having a linear core of alternating 4-linked α-d-Gal and 3-linked β-d-Gal residues. The latter bear single β-d-Xylp or a short chain of 4-linked β-d-Xyl, 6-linked β-d-Gal, and variously linked α-l-Fuc. In FSA, these polysaccharides are sulfated at different positions and devoid of regularity. Fractions of FSA possess anticoagulant, cytotoxic, and antitumor activities, which increase with the degree of sulfation. The most sulfated fraction 2.0 M that contains mainly a sulfated fucogalactan, is about half as active as anticoagulant as the standard low-molecular mass heparin (enoxaparin).
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preliminary investigation of a highly sulfated galactofucan fraction isolated from the brown alga sargassum polycystum
Carbohydrate Research, 2013Co-Authors: Maria I Bilan, Alexey A Grachev, Alexander S Shashkov, Thanh Thi Thu Thuy, Tran Thi Thanh Van, Nikolay E Nifantiev, Anatolii I UsovAbstract:A fucoidan preparation was isolated from the brown alga Sargassum polycystum (Fucales, Sargassaceae). The preparation was fractionated by anion-exchange chromatography, and two highly sulfated fractions F3 and F4 were obtained. The fractions were quite similar in composition, but different in chemical structure. F4 was analyzed by chemical methods, including desulfation, methylation, Smith degradation, and partial acid hydrolysis with mass-spectrometric monitoring, as well as by NMR spectroscopy. Several 2D NMR procedures, including HMQC-TOCSY and HMQC-NOESY, were used to obtain reliable structural information from the complex spectra. Molecules of F4 were shown to contain a backbone built up mainly of 3-linked α-l-fucopyranose 4-sulfate residues, as in many other fucoidans, but rather short sequences of these residues are interspersed by single 2-linked α-d-galactopyranose residues also sulfated at position 4. This rather unusual structural feature should have a great influence on the conformation of the polymeric molecule and may be important for biological activity of the polysaccharide. Hence, F4 is an example of a new sulfated galactofucan isolated from the brown alga. According to the data obtained, the distribution of galactose residues along the polysaccharide backbone seems to be not strictly regular, but the definitive sequence of monomers in the polymeric molecules awaits additional investigation.