Description
Spores are spherical or oval and have an anterior orifice closed by a flap of wall material (Fig. 1 0). The epispore cytoplasm extends posteriorly into a tapering extension except for U. pelseneeri (Caullery & Chappellier, 1906} Dollfus, 1925. The shape of the extension is maintained by bands or ribbons of material curved in cross-sectional view and composed of folded subunits which I i e mainly beneath the cell membrane of the epispore cytoplasm giving the cytoplasm a corrugated appearance in surface view. The spores, minus the epispore cytoplasm , range from 3 .0-5 .9 X 5 - 13.3 1-Jm, and the posterior extensions range from 10 to 43 1-1m long. The species are mostly hyperparasites of trematode or nematode sporocysts, metacercariae or juveniles ; however, one species , U. fulginosum Caullery & Mesnil , 1905 is found in the coelom of a polychete . When spores are mature and found in large numbers , their presence causes the host to be black. Seven named species. TYPE SPECIES: U. fulginosum Caullery & Mesnil, 1905. The genus Anurosporidium Guyenot, 1943 is considered to be synonymous with Urosporidium (Ormieres et al. , 1973). - o · (51 '¥ -- .... . (_/~ / ( - Figs. 6-9. Phase contrast micrograph of Minchinia armoricana spore . A prominent , anteriorly directed extension (left) originates from beneath the hinge of the lid and a similar, posteriorly directed extension (right) arises from the posterior of the spore. Bar=5 ~m . Fig. 7. Phase contrast micrograph of mature spore of H. louisiana. The spore lacks prominent episporal extensions and the fibers around the w a II are not visible. Bar=5 ~m . Fig. 8. Scanning electron micrograph of H. louisiana spore -as in Fig . 7. Fibers are clearly visible . Bar=1 ~m . Fig . 9. Transmission electron micrograph of a whole mount of a M. lusitanicum. Note the two long extensions arising as bifurcations from the posterior end of the spore and the spore lid (From Azevedo, 1984). Bar=5 ~m . I DIA These units , singly or in groups, form 2 - 4 prominent extensions of the spore which are visible in the light microscope . The extensions are 10-112 iJm long. There are 9 named species (as revised above), found as parasites of marine polychetes and molluscs. TYPE SPECIES: Minchinia chitonis (Lankester, 1895) Labbe , 1896 INCERTAE SEDIS Larsson (1987) has erected a third family Claustrosporidiidae , for the order Haplosporida with a single genus C/austrosporidium Larsson , 1987 and two species, C. gammari (Ryckeghem , 1930) Larsson , 1987 (syn .=Hap/osporidium gammari Ryckeghem , 1 930); and C. aselli (Pflugfelder, 1948) Larsson , 1987 (syn.=Haplosporidium aselli Pflugfelder , 1 948 ) . The uninucleate spores of both species lack orifices. However, in the only species , C gammari, examined by electron microscopy, the cytoplasm contains haplosporosomes in plasmod ia, sporoblasts , and spores . There is no spherulosome in the sporoplasm . C/austrosporidium gammari is found in the adipose tissue of the marine amphipod , Rivu/ogammarus pulex (Larsson , 1987). Prior to sporulation the protist exists as plasmodia with small (1 .7 to 2.0 1-1m diameter) nuclei which form pairs then appear to fuse , creating large (2.3 to 3.0 iJm diameter) nuclei followed by division to form small ( ca. 2.0 iJm ) nuclei again . Subdivision of the plasmodium then yields uninucleate sporoblasts , each of which acquire a cell wall. The wall and protoplast become the spore wall and sporoplasm , thus one spore is formed per sporoblast . The mitotic apparatus is the same as in the Haplosporidiidae and Urosporidiidae and appears to be persistent into interphase as in Hap/osporidium nelsoni (Perkins , 1975a). The main reason I have not yet accepted Larsson 's placement of the Claustrosporidiidae in the Haplosporidia is that the spores have no orifice and the spore wall is formed on the plasmalemma of the sporoblast, not in the epispore cytoplasm HAPLOSPORI silhouette is typical of most species where the epispore cytoplasm persists around the spore wall and is drawn into a posteriorly directed extension as represented in the interference contrast micrograph of U. crescens. The upper right silhouette is representative of U. spisuli where three episporal extensions are formed . The drawing of the internal detail typifies U. crescens. Spherulosome (S) in which haplosporosomes (H) form ; ribbon (R) of episporal material which provides support to the epispore cytoplasm . Bar=10 ~m for top three figures and 1 ~m for drawing of spore internal detail. and on the membrane which faces the plasmalemma of the sporoplasm as occurs in the genera Haplosporidium, Minchinia, and Urosporidium. However, there are a number of similarities which make Larsson's classification attractive. The presence of haplosporosomes in a spore-forming protist, which lacks polar filaments as in the Microspora, internal cleavage as in the Paramyxa, and polar capsules as in the Myxospora, strengthens the argument that it is one of the Haplosporidia. As noted above haplosporosomes appear to be present in the Myxospora and Paramyxa, but not in the Microspora. The presence of a mitotic apparatus which consists of a bundle of microtubules attached to spindle pole bodies in the nucleoplasm , not centrioles , also strengthens the argument . In attempts to determine the taxonomic affinities of the Claustrosporidiidae , it will be useful to examine the ultrastructure of other non- photosynthetic, non-rhizopodean , spore-forming protists which do not form an apical complex , polar capsules. or polar filaments in their life from Larsson (1987). Spore wall loosely enrobes the sporoplasm and has ridges on the outer surface . Haplosporosomes (H) . Bar=1 ~m . cycle, nor form multicellular spores . Species of the genera Coelospora and Peltomyces will be of special interest. Lange ( 1993) has examined the ultrastructure of Nephridiophaga periplanetae Lutz & Splendore , 1903 and did not find haplosporosomes: Neither were they found in Coe/osporidium chydoricola (Manier et al., 1976) , Oryctospora alata (Purrini and Weiser , 1990) , N. tangae (Purrini et al. , 1988), N. blattellae (Woolever, 1966), nor N. ormieresi (Toguebaye et al., 1986). Lange (1993) included the above 5 genera in the family Nephridiophagidae Sprague, 1970 , because species in the 5 genera form similar spores and are all found in the Malpighian tubules of arthropods . Since haplosporosomes appear to be absent (at least in species of three of the genera) and orifices are not present in the spores , he did not consider the Nephridiophagidae to be haplosporidians and further suggested that they may need to be placed in a separate phylum, placing them in incertae sedis status for the present . If the Claustrosporidiidae can be accepted as haplosporidians, then the question arises as to whether species like those in the Nephridiophagidae can be considered to also be haplosporidians. It might be reasonable to accept a gradation from species of accepted Haplosporidia (i.e ., unicellular spores with orifices) to those species with no orifice , but with haplosporosomes (the Claustrosporidiidae) to species with no orifice and no haplosporosomes (the Nephridiophagidae). All of this would be predicated on the assumption that none of the species of uncertain affinities formed spores with polar filaments or polar capsules and spores were not multicellular nor were there apical complexes formed in any cellular stages in the life cycle . It should be noted that species of Urosporidium , Haplosporidium, and Minchinia are not considered to be multicellular as found in the Paramyxa (see above) .
Type species
Figures
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Raw text
Spores are spherical or oval and have an anterior orifice closed by a flap of wall material (Fig. 1 0). The epispore cytoplasm extends posteriorly into a tapering extension except for U. pelseneeri (Caullery & Chappellier, 1906} Dollfus, 1925. The shape of the extension is maintained by bands or ribbons of material curved in cross-sectional view and composed of folded subunits which I i e mainly beneath the cell membrane of the epispore cytoplasm giving the cytoplasm a corrugated appearance in surface view. The spores, minus the epispore cytoplasm , range from 3 .0-5 .9 X 5 - 13.3 1-Jm, and the posterior extensions range from 10 to 43 1-1m long. The species are mostly hyperparasites of trematode or nematode sporocysts, metacercariae or juveniles ; however, one species , U. fulginosum Caullery & Mesnil , 1905 is found in the coelom of a polychete . When spores are mature and found in large numbers , their presence causes the host to be black. Seven named species. TYPE SPECIES: U. fulginosum Caullery & Mesnil, 1905. The genus Anurosporidium Guyenot, 1943 is considered to be synonymous with Urosporidium (Ormieres et al. , 1973). - o · (51 '¥ -- .... . (_/~ / ( - Figs. 6-9. Phase contrast micrograph of Minchinia armoricana spore . A prominent , anteriorly directed extension (left) originates from beneath the hinge of the lid and a similar, posteriorly directed extension (right) arises from the posterior of the spore. Bar=5 ~m . Fig. 7. Phase contrast micrograph of mature spore of H. louisiana. The spore lacks prominent episporal extensions and the fibers around the w a II are not visible. Bar=5 ~m . Fig. 8. Scanning electron micrograph of H. louisiana spore -as in Fig . 7. Fibers are clearly visible . Bar=1 ~m . Fig . 9. Transmission electron micrograph of a whole mount of a M. lusitanicum. Note the two long extensions arising as bifurcations from the posterior end of the spore and the spore lid (From Azevedo, 1984). Bar=5 ~m . I DIA These units , singly or in groups, form 2 - 4 prominent extensions of the spore which are visible in the light microscope . The extensions are 10-112 iJm long. There are 9 named species (as revised above), found as parasites of marine polychetes and molluscs. TYPE SPECIES: Minchinia chitonis (Lankester, 1895) Labbe , 1896 INCERTAE SEDIS Larsson (1987) has erected a third family Claustrosporidiidae , for the order Haplosporida with a single genus C/austrosporidium Larsson , 1987 and two species, C. gammari (Ryckeghem , 1930) Larsson , 1987 (syn .=Hap/osporidium gammari Ryckeghem , 1 930); and C. aselli (Pflugfelder, 1948) Larsson , 1987 (syn.=Haplosporidium aselli Pflugfelder , 1 948 ) . The uninucleate spores of both species lack orifices. However, in the only species , C gammari, examined by electron microscopy, the cytoplasm contains haplosporosomes in plasmod ia, sporoblasts , and spores . There is no spherulosome in the sporoplasm . C/austrosporidium gammari is found in the adipose tissue of the marine amphipod , Rivu/ogammarus pulex (Larsson , 1987). Prior to sporulation the protist exists as plasmodia with small (1 .7 to 2.0 1-1m diameter) nuclei which form pairs then appear to fuse , creating large (2.3 to 3.0 iJm diameter) nuclei followed by division to form small ( ca. 2.0 iJm ) nuclei again . Subdivision of the plasmodium then yields uninucleate sporoblasts , each of which acquire a cell wall. The wall and protoplast become the spore wall and sporoplasm , thus one spore is formed per sporoblast . The mitotic apparatus is the same as in the Haplosporidiidae and Urosporidiidae and appears to be persistent into interphase as in Hap/osporidium nelsoni (Perkins , 1975a). The main reason I have not yet accepted Larsson 's placement of the Claustrosporidiidae in the Haplosporidia is that the spores have no orifice and the spore wall is formed on the plasmalemma of the sporoblast, not in the epispore cytoplasm HAPLOSPORI silhouette is typical of most species where the epispore cytoplasm persists around the spore wall and is drawn into a posteriorly directed extension as represented in the interference contrast micrograph of U. crescens. The upper right silhouette is representative of U. spisuli where three episporal extensions are formed . The drawing of the internal detail typifies U. crescens. Spherulosome (S) in which haplosporosomes (H) form ; ribbon (R) of episporal material which provides support to the epispore cytoplasm . Bar=10 ~m for top three figures and 1 ~m for drawing of spore internal detail. and on the membrane which faces the plasmalemma of the sporoplasm as occurs in the genera Haplosporidium, Minchinia, and Urosporidium. However, there are a number of similarities which make Larsson's classification attractive. The presence of haplosporosomes in a spore-forming protist, which lacks polar filaments as in the Microspora, internal cleavage as in the Paramyxa, and polar capsules as in the Myxospora, strengthens the argument that it is one of the Haplosporidia. As noted above haplosporosomes appear to be present in the Myxospora and Paramyxa, but not in the Microspora. The presence of a mitotic apparatus which consists of a bundle of microtubules attached to spindle pole bodies in the nucleoplasm , not centrioles , also strengthens the argument . In attempts to determine the taxonomic affinities of the Claustrosporidiidae , it will be useful to examine the ultrastructure of other non- photosynthetic, non-rhizopodean , spore-forming protists which do not form an apical complex , polar capsules. or polar filaments in their life from Larsson (1987). Spore wall loosely enrobes the sporoplasm and has ridges on the outer surface . Haplosporosomes (H) . Bar=1 ~m . cycle, nor form multicellular spores . Species of the genera Coelospora and Peltomyces will be of special interest. Lange ( 1993) has examined the ultrastructure of Nephridiophaga periplanetae Lutz & Splendore , 1903 and did not find haplosporosomes: Neither were they found in Coe/osporidium chydoricola (Manier et al., 1976) , Oryctospora alata (Purrini and Weiser , 1990) , N. tangae (Purrini et al. , 1988), N. blattellae (Woolever, 1966), nor N. ormieresi (Toguebaye et al., 1986). Lange (1993) included the above 5 genera in the family Nephridiophagidae Sprague, 1970 , because species in the 5 genera form similar spores and are all found in the Malpighian tubules of arthropods . Since haplosporosomes appear to be absent (at least in species of three of the genera) and orifices are not present in the spores , he did not consider the Nephridiophagidae to be haplosporidians and further suggested that they may need to be placed in a separate phylum, placing them in incertae sedis status for the present . If the Claustrosporidiidae can be accepted as haplosporidians, then the question arises as to whether species like those in the Nephridiophagidae can be considered to also be haplosporidians. It might be reasonable to accept a gradation from species of accepted Haplosporidia (i.e ., unicellular spores with orifices) to those species with no orifice , but with haplosporosomes (the Claustrosporidiidae) to species with no orifice and no haplosporosomes (the Nephridiophagidae). All of this would be predicated on the assumption that none of the species of uncertain affinities formed spores with polar filaments or polar capsules and spores were not multicellular nor were there apical complexes formed in any cellular stages in the life cycle . It should be noted that species of Urosporidium , Haplosporidium, and Minchinia are not considered to be multicellular as found in the Paramyxa (see above) .