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Mazéas L, Yonamine R, Barbeyron T, Henrissat B, Drula E, Terrapon N, Nagasato C, Hervé C. Assembly and synthesis of the extracellular matrix in brown algae. Semin Cell Dev Biol 2023; 134:112-124. [PMID: 35307283 DOI: 10.1016/j.semcdb.2022.03.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 02/03/2022] [Accepted: 03/04/2022] [Indexed: 12/23/2022]
Abstract
In brown algae, the extracellular matrix (ECM) and its constitutive polymers play crucial roles in specialized functions, including algal growth and development. In this review we offer an integrative view of ECM construction in brown algae. We briefly report the chemical composition of its main constituents, and how these are interlinked in a structural model. We examine the ECM assembly at the tissue and cell level, with consideration on its structure in vivo and on the putative subcellular sites for the synthesis of its main constituents. We further discuss the biosynthetic pathways of two major polysaccharides, alginates and sulfated fucans, and the progress made beyond the candidate genes with the biochemical validation of encoded proteins. Key enzymes involved in the elongation of the glycan chains are still unknown and predictions have been made at the gene level. Here, we offer a re-examination of some glycosyltransferases and sulfotransferases from published genomes. Overall, our analysis suggests novel investigations to be performed at both the cellular and biochemical levels. First, to depict the location of polysaccharide structures in tissues. Secondly, to identify putative actors in the ECM synthesis to be functionally studied in the future.
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Affiliation(s)
- Lisa Mazéas
- CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff, France; Sorbonne Universités, UPMC Univ Paris 06, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff, France
| | - Rina Yonamine
- Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran 051-0013, Japan
| | - Tristan Barbeyron
- CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff, France; Sorbonne Universités, UPMC Univ Paris 06, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff, France
| | - Bernard Henrissat
- CNRS, Aix Marseille Univ, UMR 7257 AFMB, 13288 Marseille, France; INRAE, USC1408 AFMB, 13288 Marseille, France; Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia; Technical University of Denmark, DTU Bioengineering, DK-2800 Kgs., Lyngby, Denmark
| | - Elodie Drula
- CNRS, Aix Marseille Univ, UMR 7257 AFMB, 13288 Marseille, France; INRAE, USC1408 AFMB, 13288 Marseille, France
| | - Nicolas Terrapon
- CNRS, Aix Marseille Univ, UMR 7257 AFMB, 13288 Marseille, France; INRAE, USC1408 AFMB, 13288 Marseille, France
| | - Chikako Nagasato
- Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran 051-0013, Japan
| | - Cécile Hervé
- CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff, France; Sorbonne Universités, UPMC Univ Paris 06, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff, France.
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Yonamine R, Ichihara K, Tsuyuzaki S, Hervé C, Motomura T, Nagasato C. Changes in Cell Wall Structure During Rhizoid Formation of Silvetia babingtonii (Fucales, Phaeophyceae) Zygotes. JOURNAL OF PHYCOLOGY 2021; 57:1356-1367. [PMID: 33932028 DOI: 10.1111/jpy.13178] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 03/31/2021] [Indexed: 06/12/2023]
Abstract
We examined the ultrastructure of the cell wall and immunolocalization of alginates using specific antibodies against M-rich alginates and MG blocks during rhizoid formation in fucoid zygotes, Silvetia babingtonii. The thallus region of 24-h-old zygotes had a cell wall made of three layers with different fiber distribution. In the 12-h-old zygotes, three layers in the thallus were observed before rhizoid formation, namely the inner, middle, and outer layers. During rhizoid elongation, only the inner layer was apparent close to the rhizoid tip area. Immunoelectron microscopy detected M-rich blocks of alginate on the inner half of the cell wall, irrespective of the number of layers in the thallus and rhizoid regions. The MG blocks were seen to cover a slightly wider area than M-rich alginate blocks. It was suggested that parts of M in mannuronan would be rapidly converted to G, and MG-blocks are generated. Transcriptome analysis was performed using 3 -, 10 -, and 24-h-old zygotes after fertilization to examine the relationship between gene expression and alginate synthesis over time. The expression of two mannuronan C5-epimerase homologs that convert mannuronic acid into guluronic acid in alginates was upregulated or downregulated over the course of the examination.
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Affiliation(s)
- Rina Yonamine
- Graduate School of Environmental Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Kensuke Ichihara
- Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran, 051-0013, Japan
| | - Shiro Tsuyuzaki
- Graduate School of Environmental Earth Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Cécile Hervé
- Sorbonne Universités, CNRS, Integrative Biology of Marine Models (LBI2M), Station Biologique de Roscoff, 29680, Roscoff, France
| | - Taizo Motomura
- Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran, 051-0013, Japan
| | - Chikako Nagasato
- Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran, 051-0013, Japan
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Inoue A, Ojima T. Functional identification of alginate lyase from the brown alga Saccharina japonica. Sci Rep 2019; 9:4937. [PMID: 30894645 PMCID: PMC6426991 DOI: 10.1038/s41598-019-41351-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 03/07/2019] [Indexed: 11/26/2022] Open
Abstract
Despite the progress in massive gene analysis of brown algal species, no alginate-degrading enzyme from brown alga has been identified, impeding the understanding of alginate metabolism in brown alga. In the current study, we identified and characterized alginate lyase from Saccharina japonica using a protein-based approach. First, cDNA library was prepared from the S. japonica sporophyte. Expression screening was then performed; the encoding gene was identified and cloned; and the recombinant enzyme was purified and characterized. Alginate lyase production in algal tissues was evaluated by western blotting. The identified alginate lyase, SjAly (359 amino acids, with a predicted N-terminal secretion signal of 27 residues), is encoded by an open reading frame comprising seven exons. Recombinant SjAly exhibited endolytic alginate lyase activity, specifically toward stretches of consecutive β-D-mannuronic acid units. The optimum temperature, pH, and NaCl concentration were 30 °C, pH 8.0, and 100 mM, respectively. SjAly exhibited pronounced activity below 20 °C, the S. japonica growth temperature. SjAly was highly expressed in the blade but not the stipe and rhizoid. The data indicate that S. japonica possesses at least one active alginate lyase. This is the first report of a functional alginate lyase from brown alga, the major natural alginate producer.
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Affiliation(s)
- Akira Inoue
- Laboratory of Marine Biotechnology and Microbiology, Graduate School of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate, Hokkaido, Japan.
| | - Takao Ojima
- Laboratory of Marine Biotechnology and Microbiology, Graduate School of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate, Hokkaido, Japan
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Terauchi M, Nagasato C, Inoue A, Ito T, Motomura T. Distribution of alginate and cellulose and regulatory role of calcium in the cell wall of the brown alga Ectocarpus siliculosus (Ectocarpales, Phaeophyceae). PLANTA 2016; 244:361-77. [PMID: 27072676 DOI: 10.1007/s00425-016-2516-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Accepted: 03/31/2016] [Indexed: 06/05/2023]
Abstract
MAIN CONCLUSION This work investigated a correlation between the three-dimensional architecture and compound-components of the brown algal cell wall. Calcium greatly contributes to the cell wall integrity. Brown algae have a unique cell wall consisting of alginate, cellulose, and sulfated polysaccharides. However, the relationship between the architecture and the composition of the cell wall is poorly understood. Here, we investigated the architecture of the cell wall and the effect of extracellular calcium in the sporophyte and gametophyte of the model brown alga, Ectocarpus siliculosus (Dillwyn) Lyngbye, using transmission electron microscopy, histochemical, and immunohistochemical studies. The lateral cell wall of vegetative cells of the sporophyte thalli had multilayered architecture containing electron-dense and negatively stained fibrils. Electron tomographic analysis showed that the amount of the electron-dense fibrils and the junctions was different between inner and outer layers, and between the perpendicular and tangential directions of the cell wall. By immersing the gametophyte thalli in the low-calcium (one-eighth of the normal concentration) artificial seawater medium, the fibrous layers of the lateral cell wall of vegetative cells became swollen. Destruction of cell wall integrity was also induced by the addition of sorbitol. The results demonstrated that electron-dense fibrils were composed of alginate-calcium fibrous gels, and electron negatively stained fibrils were crystalline cellulose microfibrils. It was concluded that the spatial arrangement of electron-dense fibrils was different between the layers and between the directions of the cell wall, and calcium was necessary for maintaining the fibrous layers in the cell wall. This study provides insights into the design principle of the brown algal cell wall.
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Affiliation(s)
- Makoto Terauchi
- Graduate School of Environmental Science, Hokkaido University, Sapporo, 060-0810, Japan
- Research Center for Inland Seas, Kobe University, Kobe, 657-8501, Japan
| | - Chikako Nagasato
- Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran, 051-0013, Japan.
| | - Akira Inoue
- Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, 041-8611, Japan
| | - Toshiaki Ito
- Electron Microscope Laboratory, Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan
| | - Taizo Motomura
- Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran, 051-0013, Japan
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Michel G, Tonon T, Scornet D, Cock JM, Kloareg B. The cell wall polysaccharide metabolism of the brown alga Ectocarpus siliculosus. Insights into the evolution of extracellular matrix polysaccharides in Eukaryotes. THE NEW PHYTOLOGIST 2010; 188:82-97. [PMID: 20618907 DOI: 10.1111/j.1469-8137.2010.03374.x] [Citation(s) in RCA: 250] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
• Brown algal cell walls share some components with plants (cellulose) and animals (sulfated fucans), but they also contain some unique polysaccharides (alginates). Analysis of the Ectocarpus genome provides a unique opportunity to decipher the molecular bases of these crucial metabolisms. • An extensive bioinformatic census of the enzymes potentially involved in the biogenesis and remodeling of cellulose, alginate and fucans was performed, and completed by phylogenetic analyses of key enzymes. • The routes for the biosynthesis of cellulose, alginates and sulfated fucans were reconstructed. Surprisingly, known families of cellulases, expansins and alginate lyases are absent in Ectocarpus, suggesting the existence of novel mechanisms and/or proteins for cell wall expansion in brown algae. • Altogether, our data depict a complex evolutionary history for the main components of brown algal cell walls. Cellulose synthesis was inherited from the ancestral red algal endosymbiont, whereas the terminal steps for alginate biosynthesis were acquired by horizontal gene transfer from an Actinobacterium. This horizontal gene transfer event also contributed genes for hemicellulose biosynthesis. By contrast, the biosynthetic route for sulfated fucans is an ancestral pathway, conserved with animals. These findings shine a new light on the origin and evolution of cell wall polysaccharides in other Eukaryotes.
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Affiliation(s)
- Gurvan Michel
- UPMC University Paris 6, UMR 7139 Marine Plants and Biomolecules, Station Biologique de Roscoff, F-29682 Roscoff, Bretagne, France.
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Nagasato C, Inoue A, Mizuno M, Kanazawa K, Ojima T, Okuda K, Motomura T. Membrane fusion process and assembly of cell wall during cytokinesis in the brown alga, Silvetia babingtonii (Fucales, Phaeophyceae). PLANTA 2010; 232:287-98. [PMID: 20473516 DOI: 10.1007/s00425-010-1188-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Accepted: 04/29/2010] [Indexed: 05/07/2023]
Abstract
During cytokinesis in brown algal cells, Golgi-derived vesicles (GVs) and flat cisternae (FCs) are involved in building the new cell partition membrane. In this study, we followed the membrane fusion process in Silvetia babingtonii zygotes using electron microscopy together with rapid freezing and freeze substitution. After mitosis, many FCs were formed around endoplasmic reticulum clusters and these then spread toward the future cytokinetic plane. Actin depolymerization using latrunculin B prevented the appearance of the FCs. Fusion of GVs to FCs resulted in structures that were thicker and more elongated (EFCs; expanded flat cisternae). Some complicated membranous structures (MN; membranous network) were formed by interconnection of EFCs and following the arrival of additional GVs. The MN grew into membranous sacs (MSs) as gaps between the MNs disappeared. The MSs were observed in patches along the cytokinetic plane. Neighboring MSs were united to form the new cell partition membrane. An immunocytochemical analysis indicated that fucoidan was synthesized in Golgi bodies and transported by vesicles to the future cytokinetic plane, where the vesicles fused with the FCs. Alginate was not detected until the MS phase. Incubation of sections with cellulase-gold showed that the cellulose content of the new cross wall was not comparable to that of the parent cell wall.
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Affiliation(s)
- Chikako Nagasato
- Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran, Japan.
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Stafford C, Callow J, Green J. Isolation and characterization of Plasma membranes fromFucus serratuseggs. ACTA ACUST UNITED AC 1992. [DOI: 10.1080/00071619200650371] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Abstract
Zygotes of fucoid algae have long been studied as a paradigm for cell polarity. Polarity is established early in the first cell cycle and is then expressed as localized growth and invariant cell division. The fertilized egg is a spherical cell and, by all accounts, bears little or no asymmetry. Polarity is acquired epigenetically a few hours later in the form of a rhizoid/thallus axis. The initial stage of polarization is axis selection, during which zygotes monitor environment gradients to determine the appropriate direction for rhizoid formation. In their natural setting in the intertidal zone, sunlight is probably the most important polarizing vector; rhizoids form away from the light. The mechanism by which zygotes perceive environmental gradients and transduce that information into an intracellular signal is unknown but may involve a phosphatidylinositol cycle. Once positional information has been recorded, the cytoplasm and membrane are reorganized in accordance with the vectorial information. The earliest detectable asymmetries in the polarizing zygote are localized secretion and generation of a transcellular electric current. Vesicle secretion and the inward limb of the current are localized at the presumptive rhizoid. The transcellular current may establish a cytoplasmic Ca2+ gradient constituting a morphogenetic field, but this remains controversial. Localized secretion and establishment of transcellular current are sensitive to treatment with cytochalasins, indicating that cytoplasmic reorganization is dependent on the actin cytoskeleton. The nascent axis at first is labile and susceptible to reorientation by subsequent environmental vectors but soon becomes irreversibly fixed in its orientation. Locking the axis in place requires both cell wall and F-actin and is postulated to involve an indirect transmembrane bridge linking cortical actin to cell wall. This bridge anchors relevant structures at the presumptive rhizoid and thereby stabilizes the axis. Approximately halfway through the first cell cycle, the latent polarity is expressed morphologically in the form of rhizoid growth. Elongation is by tip growth and does not appear to be fundamentally different from tip growth in other organisms. The zygote always divides perpendicular to the growth axis, and this is controlled by the microtubule cytoskeleton. Two microtubule-organizing centers on the nuclear envelope rotate such that they align with the growth axis. They then serve as spindle poles during mitosis. Cytokinesis bisects the axial spindle, resulting in a transverse crosswall. Although the chronology of cellular events associated with polarity is by now rather detailed, causal mechanisms remain obscure.
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Affiliation(s)
- D L Kropf
- Department of Biology, University of Utah, Salt Lake City 84112
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The need for a constraining layer in the formation of monodomain helicoids in a wide range of biological structures. Tissue Cell 1988; 20:133-43. [DOI: 10.1016/0040-8166(88)90013-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/1987] [Indexed: 11/21/2022]
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Sulfation and transport of basement membrane proteoglycans, as visualized by35S-sulfate radioautography in the endodermal cells of the rat parietal yolk sac. ACTA ACUST UNITED AC 1985; 173:127-45. [DOI: 10.1002/aja.1001730206] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Catt JW, Vithanage HI, Callow JA, Callow ME, Evans LV. Fertilization in brown algae. V. Further investigations of lectins as surface probes. Exp Cell Res 1983; 147:127-33. [PMID: 6617757 DOI: 10.1016/0014-4827(83)90277-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The binding of FITC- (fluorescein isothiocyanate), Au- and 125I-labelled lectins (conA, RCA120 (Ricinus communis agglutinin, MW 120 000) and FBP (fucose-binding protein from Lotus tetragonobolus)) to gametes of Fucus serratus and their physiological effects on fertilization have been studied. Results indicate that eggs strongly bind FITC- and Au-labelled conA and RCA120, whilst FITC-FBP binds strongly to sperm. All three iodinated lectins bound to eggs but this was apparently non-specific and similar in magnitude to the binding of iodinated bovine serum albumin. The results suggested the possibility of two distinct types of lectin receptor on egg surfaces: non-specific, highly abundant receptors and less abundant, specific receptors, possibly locally aggregated. All three lectins inhibit fertilization, FBP being the most effective.
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Vithanage HI, Catt JW, Callow JA, Callow ME, Evans LV. Fertilization in brown algae. IV. Appearance of sperm-specific antigens on fertilized eggs. J Cell Sci 1983; 60:103-8. [PMID: 6192131 DOI: 10.1242/jcs.60.1.103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Flagella antigens from sperm of Fucus serratus have been used to raise antibodies in rabbits. The immunoglobulin G fraction inhibits fertilization with some degree of species specificity. The antigens detected on sperm are not present on unfertilized egg membranes, but appear after fertilization. The common antigens on the fertilized egg can be distinguished from the cell wall material that is also released on fertilization.
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Millard P, Evans LV. Sulphate uptake in the unicellular marine red algaRhodella maculata. Arch Microbiol 1982. [DOI: 10.1007/bf01054000] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Bolwell GP, Callow JA, Evans LV. Fertilization in brown algae. III. Preliminary characterization of putative gamete receptors from eggs and sperm of Fucus serratus. J Cell Sci 1980; 43:209-24. [PMID: 7191429 DOI: 10.1242/jcs.43.1.209] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Membrane fractions have been isolated from eggs of Fucus serrratus which inhibit fertilization in a species-specific manner. This activity is destroyed by alpha-fucosidase and alpha-mannosidase. Some 6% of the protein of this membrane fraction binds to Con A-agarose, following SDS solubilization, and when eluted with alpha-methyl mannoside inhibits fertilization when preincubated with sperm, but not eggs. This inhibitory activity is species-specific and destroyed by alpha-fucosidase but not by trypsin. SDS-gel electrophoresis reveals 1 band staining strongly with Coomassie Brilliant Blue G and weakly with the PAS reagent. This major band represents a glycoprotein with an approximate molecular weight of 30 000 Daltons. Membrane fractions from sperm of Fucus serratus solubilized in KC1 yielded a protein-containing fraction, after affinity chromatography on desulphated focoidan-Sepharose. This fraction is 100-fold more effective in inhibiting fertilization after preincubation with eggs than either Con A or fucose-binding protein. It is species-specific and inhibition is reversed when pretreated eggs are washed with fucoidan. Activity is destroyed by heat and trypsin and only one diffuse band is apparent on SDS gels. This stains positively with Coomassie Brilliant Blue G but not with PAS and has a molecular weight of approximately 60 000 Daltons. Tentative calculation of the numbers of putative receptor molecules gives a figure of 2.5 X 10(9) receptors per egg and 1.8 X 10(6) receptors per sperm.
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Dauwalder M, Whaley WG, Starr RC. Differentiation and secretion in Volvox. JOURNAL OF ULTRASTRUCTURE RESEARCH 1980; 70:318-35. [PMID: 7373698 DOI: 10.1016/s0022-5320(80)80015-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Brawley SH, Quatrano RS. Sulfation of fucoidin in Fucus embryos. IV. Autoradiographic investigations of fucoidin sulfation and secretion during differentiation and the effect of cytochalasin treatment. Dev Biol 1979; 73:193-205. [PMID: 499666 DOI: 10.1016/0012-1606(79)90063-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Percival E. The polysaccharides of green, red and brown seaweeds: Their basic structure, biosynthesis and function. ACTA ACUST UNITED AC 1979. [DOI: 10.1080/00071617900650121] [Citation(s) in RCA: 178] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Bolwell GP, Callow JA, Callow ME, Evans LV. Fertilization in brown algae. II. Evidence for lectin-sensitive complementary receptors involved in gamete recognition in Fucus serratus. J Cell Sci 1979; 36:19-30. [PMID: 457806 DOI: 10.1242/jcs.36.1.19] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fertilization in Fucus serratus is directly proportional to the number of sperm added, saturating at approximately 250 sperm per egg with an apparent Km of 120 sperm per egg. The effect of a range of lectins on fertilization has been tested. Preincubation of gametes with Con A and fucose-binding protein (FBP) inhibited fertilization. At low concentrations this was by specifically binding to eggs; at high concentrations pretreatment of either gametes inhibited fertilization probably due to cytotoxicity. Fertilization was not inhibited by simple sugar haptens, but polysaccharides containing fucosyl or mannosyl residues (yeast mannan, fucoidan, ascophyllan) inhibited fertilization by binding to sperm. Pretreatment of eggs with alpha-fucosidase or alpha-mannosidase was effective in inhibiting fertilization. All the results indirectly demonstrate that fertilization in Fucus serratus is based on an association between fucosyl- and mannosyl-containing ligands on the egg surface and specific carbohydrate-binding receptors on the sperm surface.
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Callow ME, Evans LV, Bolwell GP, Callow JA. Fertilization in brown algae. I. SEM and other observations on Fucus serratus. J Cell Sci 1978; 32:45-54. [PMID: 581287 DOI: 10.1242/jcs.32.1.45] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The cell wall secreted immediately following sperm entry into an egg can be visualized by the fluorescent dye Calcofluor white. Cell wall secretion precedes nuclear fusion by 10-20 min. SEM observations of the surface of unfertilized and fertilized eggs and sperm attachment to eggs are described. These results are discussed in relation to fertilization in sea urchins and the biochemical phenomena associated with egg-sperm recognition in Fucus.
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