Description
GRASSE 1926 of chl of bic By 0JVIND MOESTRUP than a Paraph The bicosoecids form a well-defined group other of heterotrophic heterokont flagellates . 3. Cel Recent studies on 18S rRNA (Leipe et al. , specie 1995) have shown that Cafeteria , a system primitive bicosoecid, is one of the most 4. The primitive heterokont protists and precedes naked both the oomycetes and the heterokont algae. 5. Rep Bicosoecids (sometimes erroneously spelled reprod bicoecids or bikocoecids) are phagotrophic 6. Fre flagellates in fresh water and marine widely environments. Only three genera are known , tropic comprising c. 45 described species. Most 7. Dia species are unicells but some fo rm colonies . identi The great majority belongs to the genus shape Bicosoeca. Bicosoecids are biflagellate and cells. the movements of the anterior hairy flagellum draws the swimming cell forward Bicoso in the water. The smooth flagellum is (1995) usually directed posteriorly and may be and Ca used for attachment (Fig. 1). When or abs attached , the movements of the hairy flagellum create a water current that draws water and food particles towards the peristome area of the cell (Figs. 1A, B). This area is supported by a broad band of microtubules , now known to be homologous 1. Cel with a flagellar root that serves in food 1 '. E uptake in other hetero- and mixotrophic heterokonts (Moestrup , 1995). In the light 2. Smo microscope, the peristome area may be th visible as a lip-like structure. Cells of 2 -. A Bicosoeca are loricate and the cells attach to ti the inside bottom of the lorica with the su smooth flagellum tip . Cafeteria and Pseudobodo are naked and freeswimm ing but Gen may attach transiently to various surfaces, including the water film . Colorl poster Key characters organi textur 1. Cells are biflagellate . The flagellar and al apparatus is diagnostic for the group and is thicke described above. be sta (Fig . ls are phagotrophic and lack all traces oroplast , indicating that the ancestors osoecids were heterotrophic rather uto- or mixotrophic protists (comp. ysomonas). Cells feed on bacteria or eukaryotes . ls lack ejectile organelles. Freshwater s possess a contractile vacuole . cell is surrounded by a lorica o r (Figs 1-4) . roduction is by fission . Sexual uction is unknown . shwater or marine species , very distributed , some species occur in al as well as temperate areas . gnostic features used in species fication are cell size , shape, lorica and texture , single or colony-forming ecids were classified by Moestrup into two families , Bicosoecaceae feteriaceae, depending on the presence ence of a lorica. bLM ls naked, not surrounded by a lorica. 2 ach cell living in a lorica .... Bicosoeca oth posterior flagellum attached to e surface directly .... ... ..... ... Cafeteria thin thread of mucus extends from the p of the posterior flagellum to the bstrate .... .. .. ..... .... .. .. .. ..... Pseudobodo us Bicosoeca James-Clark, 1866 ess cells attached by the tip of the ior flagellum to the bottom of an c lorica of various shapes and es. Some lorica types are very thin most transparent, whilst others are r and variously ornamented . They may lked (Figs . 1A-D , 2) or unstalked 1 E) , and species may be BICOSOEC free-swimming or attached , e.g. attached to diatoms or other protists. C D A B E Undisturbed cells . C,D, Cells that have withdrawn into the cell with the hairy flagellum coiled up. E. B. planctonica, a planktonic species with stalkless lorica. x2000. (from V eHs, 1992 ) Cell shape more or less rounded . The front flagellum is directed out of the lorica when the cell is undisturbed or swimming. When disturbed , the flagellum retracts and coils up rapidly on the anterior end of the cell (Figs 1 C-E) , and the cell withdraws to the bottom of the lorica. In some species , the daughter cells settle on the parent lorica and colonies develop. Species of Bicosoeca phagocytize bacteria or eukaryotic algae (Moestrup & Thomsen 1976). Nearly 4 0 known species , mostly in fresh water. See Preisig et al. (1991 ). Bicosoeca mignotii Moestrup , Thomsen & Hibberd (Fig. 1A-E) . Cells 3-4 11m long and 5-7 11m wide . Lorica elongate ovoid, transparent and delicate. Lorica chamber 10-15 11m long , 5-7 11m wide , with a 5-10 ~Lm-long stalk that attaches to a substrate by a small disc. Anterior end of the lorica divided into two opposing beak-like parts . Lorica apparently amorphous, the stalk fibrous. Very common freshwater species , in the plankton or attached. Known from the inner Baltic, Denmark, and England but almost certainly much more widely distributed (V0rs 1992). long-stalked , bell-shaped lorica. The cell on the right in Fig . 28 has only half completed formation of its lorica. A, anoptral contrast, x1 000 . B. shadowcast whole mount, x27,000 . ( Original photographs courtesy of H. A . Thomsen) . 692 BICOSOECIDA a diet of
Type species
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Raw text
GRASSE 1926 of chl of bic By 0JVIND MOESTRUP than a Paraph The bicosoecids form a well-defined group other of heterotrophic heterokont flagellates . 3. Cel Recent studies on 18S rRNA (Leipe et al. , specie 1995) have shown that Cafeteria , a system primitive bicosoecid, is one of the most 4. The primitive heterokont protists and precedes naked both the oomycetes and the heterokont algae. 5. Rep Bicosoecids (sometimes erroneously spelled reprod bicoecids or bikocoecids) are phagotrophic 6. Fre flagellates in fresh water and marine widely environments. Only three genera are known , tropic comprising c. 45 described species. Most 7. Dia species are unicells but some fo rm colonies . identi The great majority belongs to the genus shape Bicosoeca. Bicosoecids are biflagellate and cells. the movements of the anterior hairy flagellum draws the swimming cell forward Bicoso in the water. The smooth flagellum is (1995) usually directed posteriorly and may be and Ca used for attachment (Fig. 1). When or abs attached , the movements of the hairy flagellum create a water current that draws water and food particles towards the peristome area of the cell (Figs. 1A, B). This area is supported by a broad band of microtubules , now known to be homologous 1. Cel with a flagellar root that serves in food 1 '. E uptake in other hetero- and mixotrophic heterokonts (Moestrup , 1995). In the light 2. Smo microscope, the peristome area may be th visible as a lip-like structure. Cells of 2 -. A Bicosoeca are loricate and the cells attach to ti the inside bottom of the lorica with the su smooth flagellum tip . Cafeteria and Pseudobodo are naked and freeswimm ing but Gen may attach transiently to various surfaces, including the water film . Colorl poster Key characters organi textur 1. Cells are biflagellate . The flagellar and al apparatus is diagnostic for the group and is thicke described above. be sta (Fig . ls are phagotrophic and lack all traces oroplast , indicating that the ancestors osoecids were heterotrophic rather uto- or mixotrophic protists (comp. ysomonas). Cells feed on bacteria or eukaryotes . ls lack ejectile organelles. Freshwater s possess a contractile vacuole . cell is surrounded by a lorica o r (Figs 1-4) . roduction is by fission . Sexual uction is unknown . shwater or marine species , very distributed , some species occur in al as well as temperate areas . gnostic features used in species fication are cell size , shape, lorica and texture , single or colony-forming ecids were classified by Moestrup into two families , Bicosoecaceae feteriaceae, depending on the presence ence of a lorica. bLM ls naked, not surrounded by a lorica. 2 ach cell living in a lorica .... Bicosoeca oth posterior flagellum attached to e surface directly .... ... ..... ... Cafeteria thin thread of mucus extends from the p of the posterior flagellum to the bstrate .... .. .. ..... .... .. .. .. ..... Pseudobodo us Bicosoeca James-Clark, 1866 ess cells attached by the tip of the ior flagellum to the bottom of an c lorica of various shapes and es. Some lorica types are very thin most transparent, whilst others are r and variously ornamented . They may lked (Figs . 1A-D , 2) or unstalked 1 E) , and species may be BICOSOEC free-swimming or attached , e.g. attached to diatoms or other protists. C D A B E Undisturbed cells . C,D, Cells that have withdrawn into the cell with the hairy flagellum coiled up. E. B. planctonica, a planktonic species with stalkless lorica. x2000. (from V eHs, 1992 ) Cell shape more or less rounded . The front flagellum is directed out of the lorica when the cell is undisturbed or swimming. When disturbed , the flagellum retracts and coils up rapidly on the anterior end of the cell (Figs 1 C-E) , and the cell withdraws to the bottom of the lorica. In some species , the daughter cells settle on the parent lorica and colonies develop. Species of Bicosoeca phagocytize bacteria or eukaryotic algae (Moestrup & Thomsen 1976). Nearly 4 0 known species , mostly in fresh water. See Preisig et al. (1991 ). Bicosoeca mignotii Moestrup , Thomsen & Hibberd (Fig. 1A-E) . Cells 3-4 11m long and 5-7 11m wide . Lorica elongate ovoid, transparent and delicate. Lorica chamber 10-15 11m long , 5-7 11m wide , with a 5-10 ~Lm-long stalk that attaches to a substrate by a small disc. Anterior end of the lorica divided into two opposing beak-like parts . Lorica apparently amorphous, the stalk fibrous. Very common freshwater species , in the plankton or attached. Known from the inner Baltic, Denmark, and England but almost certainly much more widely distributed (V0rs 1992). long-stalked , bell-shaped lorica. The cell on the right in Fig . 28 has only half completed formation of its lorica. A, anoptral contrast, x1 000 . B. shadowcast whole mount, x27,000 . ( Original photographs courtesy of H. A . Thomsen) . 692 BICOSOECIDA a diet of