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ENDOSPORA
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ENDOSPORA , a natural See also:group or class of the See also:Sporozoa, consisting of the orders Myxosporidia, Actinomyxidia, Sarcosporidia and Haplosporidia, together with various insufficiently-known forms (Sero- and Exosporidia), regarded at See also:present as Sporozoa incertae sedis. The distinguishing feature of the group is that the spore-See also:mother-cells (pansporoblasts) arise in the interior of the See also:body of the See also:parent-individual; in other words, sporulation is endogenous. Another very See also:general character—though not so universal—is that the adult trophozoite possesses more than one See also:nucleus, usually many (i.e. it is multinucleate). In the See also:majority of forms, though apparently not in all (e.g. certain Microsporidia), sporulation goes on coincidently with growth and trophic See also:life. With regard to the origin of the group, the See also:probability is greatly in favour of a Rhizopod ancestry. The entire See also:absence, at any known See also:period, of a flagellate or even gregariniform phase; on the other See also:hand, the amoeboid nature of the trophozoites in very many cases together with the formation of pseudopodia; and, lastly, the See also:simple endogenous spore-formation characteristic of the See also:primitive forms,—are all points which support this view, and exclude any See also:hypothesis of a Flagellate origin, such as, on the contrary, is probably the See also:case in the See also:Ectospora (q.v.).
1. See also:Order Myxosporidia. The Myxosporidia, or, more correctly, the dense masses formed by their spores, were- well known to the earlier zoological observers. The parasites in fishes were called by See also: In spite, however, of the contributions of numerous workers since then (e.g. Doflein, See also:Cohn, Stempell and others), there are still one or two very important points, such as the occurrence of sexual conjugation, upon which See also:light is required. Although pre-eminently parasites of fishes, Myxosporidia also occur, in a few cases, in other Vertebrates (frogs and See also:reptiles); no instance of their presence in a warm-blooded Vertebrate has, however, yet been described. One suborder (the Microsporidia or Cryptocystes) is See also:pretty equally distributed between fishes on the one hand and Invertebrates—chiefly, but not exclusively, Arthropods—on the other. The parasites are frequently the cause of severe and fatal illness in their hosts, and devastating epidemics of Occurrence and See also:habitat. myxosporidiosis have often been reported (e.g. among See also:carp and See also:barbel in See also:continental See also:rivers, due to a Myxobolus, and among See also:crayfish in France, to Thelohania). The seat of the invasion and the mode of See also:parasitism are extremely varied. Practically any See also:organ or See also:tissue may be attacked, excepting, apparently, the testis and See also:cartilage and See also:bone. In one instance at least (that of Nosema bombycis of the silkworm) the parasites penetrate into the ova, so that true hereditary infection occurs, the progeny being See also:born with the disease. The parasites may be either See also:free in some lumen, such as that of the See also:gall See also:bladder or urinary bladder (not of the alimentary See also:canal, or the body-cavity itself), when they are known as coelozoic forms; or in intimate relation with some tissue, intracellular while See also:young but becoming intercellular in the adult phase (histozoic forms); or entirely intracellular (cytozoic forms). Among the histozoic and cytozoic types, moreover, two well-defined conditions, concentration and diffuse infiltration, occur. In the former, the parasitic See also:zone is strictly limited, and well-marked cysts are formed; in the latter, the infection spreads throughout the neighbouring tissue, and the parasitic development becomes inextricably commingled with the See also:host's cells. Sometimes, as shown by See also:Woodcock (45), there may be an See also:attempt on the See also:part of the host's tissue to circumscribe and check the growth of these parasitic areas, which results in the formation of pseudocysts, quite different in See also:character from true cysts. The most noticeable feature about the Myxosporidian trophozoite is its amoeboid Morpho• and Rhizopod-like character. logy. Pseudopodia of various kinds, from long slender ones (fig. 3, B) to See also:short See also:blunt lobose ones, are of general From Wasielewski, Sporosoenkunde. occurrence, being most easily observed, of FIG. a. Tro hozoite of S haeros ora See also:diver ens, Thel. course in the free-living forms. The pseudo- 3' P p p g (See also:par. Blennius and s. l¢brus), x 750. ec, Ectoplasm; en, endoplasm; sp, spores, each with four our See also:pole capsules. podia serve chiefly for See also:movement and attach- From Lankester's See also:Treatise on See also:Zoology, vol. See also:Protozoa. ment, and never, it should be noted, for the B. Spore-bearing trophozoite of Leptotheca agilis, Thel. (par. Trygon and Scorpaena), injection of solid See also:food-particles, as in the X 750. ps, Pseudopodia localized at the anterior end; f.gr, fatty granules similarly case of Amoebae. The general See also:protoplasm is localized; r.gr, refringent granules; sp, spores, two in number. divisible into ectoplasm and endoplasm. The former is a clear, It may be as See also:low as two (as in free-living forms, e.g. Leptotheca), finely-granular layer, of which the pseudopodia are mainly See also:con- stituted (fig. 3, A). In one or two instances (e.g. Myxidium lieberkuhnii) the ectoplasm shows a See also:vertical striation, and in the older trophozoites breaks down partially, appearing like a See also:fur of delicate, non-motile filaments. A somewhat similar modifica- tion is found in Myxocystis. The endoplasm is more fluid, and contains numerous inclusions of a granular nature, as well as vacuoles of varying See also:size. In the endoplasm are lodged the nuclei, of which in an adult trophozoite there may be very many; they are all derived by multiplication from the single nucleus with which the young individuals begin life, the number in-creasing as growth proceeds. Spore-formation goes on entirely in the endoplasm. The number of spores formed is very variable. ,ec From Lankester's Treatise on Zoology, vol. Protozoa, from Wasielewski, after Th@lohan. From Lankester's Treatise on Zoology, vol. Protozoa. m,f, Muscle fibrils, retaining their striation. myx, Cysts of the See also:parasite, lying between the fibrils. in which case a large amount of trophic protoplasm is unconverted into spores; or, on the other hand, the number spore. of spores may be very See also:great (as in tissue-parasites), formation; practically the whole of the parent-body being thus Inuitipliused up. The sporont may or may not encyst at the catrve commencement of sporulation. In the free-living forms processes. there is no cyst-membrane secreted; but in certain Glugeidae, on the other hand, the ectoplasm becomes altered into a See also:firm, enclosing layer, the ectorind, which forms a thick cyst-See also:wall (fig. 5). The See also:process of sporulation begins by the segregation of small quantities of endoplasm around certain of the nuclei, to See also:form little, rounded bodies, the pansporoblasts. There may be either very many or only few pansporoblasts See also:developed; in some cases, indeed, there is only one, the sporont either itself becoming a pansporoblast (certain Microsporidia), or giving rise to a solitary one (Ceratomyxidae). The pansporoblast constituted, nuclear multiplication goes on preparatory to the formation of sporoblasts, which in their turn become spores (see See also:figs. 4 and 5). Not all the nuclei thus formed, however, are made use of. In the Phaenocystes there are always two sporoblasts developed in each pansporoblast; in the Cryptocystes there may be from one to several. Around each sporoblast a spore-membrane is secreted, which usually has the form of two valves. It has recently been shown by Leger and See also:Hesse (29b) that, in many Phaenocystes at any See also:rate, each of these valves is formed by a definite nucleated portion of the sporoblast. The spores themselves vary greatly in size and shape (figs. 7 and 8). They may be as small as r • 5 µby iu (as in a See also:species of Nosema), or as large as See also:ioo µ by 12 At (as in Ceratomyxa). A conspicuous feature in the structure of a fully-developed spore is the polar-capsules, of which there may be either I, 2, or 4 to each. In the Phaenocystes the polar-capsules are visible in the fresh See also:condition, but not in the Cryptocystes. The polar-See also:capsule is an organella which recalls the nematocyst of a Hydrozoan, containing a spirally-coiled filament, often of great length, which is shot out on the application of a suitable stimulus. Normally, as was within an envelope, the spore membrane (sp.m). g, More advanced See also:stage. h, Spore completely developed, with two polar capsules and sporoplasm containing an iodinophilous vacuole. i, Abnormal spore containing six polar capsules. at, Nuclei. sp.bl, Definitive sporoblast. r.n, Residuary nuclei. vac, Vacuole. r.p.c, Rudiment of p.c, polar capsule. n.p.c, Nuclei of polar capsules. iod.vac, Iodinophilous vacuole. n.sp, Nuclei of sporoplasm. ingeniously shown by Thelohan (43), the See also:digestive juices of the fresh host serve this purpose, but various artificial means may suffice. The See also:function of the everted filament is probably to secure the See also:attachment of the spore to the epithelium of the new host. In the Phaenocystes, in connexion with each polar-capsule, a small nuclear body can be generally made out; these two little nuclei are those of the two " capsulogenous " areas of the protoplasm of the pansporoblast, which formed the capsules. The sporoplasm, representing the sporozoite, is always single. Never- ect v.:t See also:Pad., 060 O p o oO ego y'F-Cr ~006Y oo°~oD o BZI 0000 D~Oo n.''' - 0'000 U 0 OHO oQoeo Q'0 pppbl. 0 co oo° op,po From Woodcock, Proc. and Trans. of the See also:Liverpool Biological Society, 1004. ect, Ectorind. velopment of the pansporo- end, Endoplasm. blasts. endoth, See also:Fold of the mucous mem- sp, Ripe spores, filling the brane, normal in character. greater part of the cyst. p.sp.bl, Various stages in the de- n, Large (vegetative) nuclei. theless, in the Phaenocystes it is invariably binuclear; and, in the Microsporidia, the nucleus, at first single, gives rise later to four nuclei, two of which are regarded by Stempell (42) as corresponding to those of two polar-capsules (of which only one is developed in the spore), the remaining two representing germ-nuclei. Hence it is possible that the Myxosporidian sporoplasm Ix. 13really consists of two, incompletely-divided (See also:sister) germs. Moreover, it is supposed by some that these two nuclei fuse together later, this See also:act representing a sexual conjugation; since the earliest known phases of young trophozoites (amoebulae) have been described as uninuclear. In addition to spore-formation, two or three modes of endogenous See also:reproduction, serving for auto-infection, have been made known. One, termed by Doflein plasmotomy, consists either in the See also:division of the (multinucleate) trophozoite into two, by more or less equal fission (simple plasmotomy), or in the budding-off. from the parent trophozoite, of several portions (example: Myxidium lieberkiihnii, fig. 6). A variety of this method has been described by Stempell (40) in the case of the young trophozoites (meronts) of Thelohania mulleri, which may See also:divide into two while still uninuclear; and by rapid successive divisions chains of meronts may be formed, the different individuals being incompletely separated. Another method, which is probably chiefly responsible for the rapid spread of tissue-parasites and See also:cell-parasites (such as Myxobolidae and Glugeidae) through their host's tissue in the condition of diffuse infiltration, consists in multiple nuclear division, and the liberation of amoebulae while the, parasite is yet quite young and possesses only few nuclei. As Woodcock has pointed out in considering the case of Glugea stephani, it is very probable that this " multiplicative reproduction," in diffuse infiltration, is to be looked upon as a separation of the pansporoblastrudiments as daughter-individuals; i.e. that the pansporoblasts are, in certain circumstances, capable of See also:independent existence as little sporonts. A further stage in this direction of See also:evolution is seen, according to Stempell, in Thelohania, Pleistophora and other types where the whole individual becomes one reproductive organella; such forms are to be considered as examples of a phylogenetic individualization of the pansporoblasts, which now exist as solitary sporonts. An extreme case of this " reduction of the individual " is found, apparently in the genus Nosema, as lately characterized by See also:Perez (34), where vast See also:numbers of See also:minute entirely independent sporonts (pansporoblasts) are produced, each of which gives rise to only a single spore. The Myxosporidia are divided into two suborders, the Phaenocystes and the Cryptocystes. Some authors have of See also:late years separated these two divisions and raised each to the See also:rank of a distinct order, considering that they are not more closely related to each other than to other Endosporan orders. We think this is a See also:mistake; and it is very interesting to find that Leger and Hesse (1908) have described (29a) a new genus of Phaenocystes, Coccomyxa, which represents a type intermediate between these two suborders, and shows that they are closely connected. Suborder 1: Phaenocystes, Gurley. Spores relatively large, with generally two or four polar-capsules, visible in the fresh ClsaslAcacondition. There are nearly always two spores formed Qas in each pansporoblast. See also:Section (a) : Disporea. Only two spores (i.e. one pansporoblast) produced in each individual trophozoite. The greatest length of the spore is at right angles to the See also:plane of the suture. One See also:family, Ceratomyxidae, including two genera, Ceratomyxa (fig. 3, B) and Leptotheca, typically " free " parasites, mostly from the gall bladders of fishes. The valves of the spore in the former genus are prolonged into hollow cones. The type-species of this genus is C. sphaerulosa, from Mustelus and Galeus; that of Leptotheca is L. agilis, from Trygon. Section (b) : Polysporea. More than two spores, generally very many, are produced typically by each individual trophozoite. The greatest length of the spore is usually in the sutural plane. Family, Myridiidae. Spores with two polar-capsules, and with-out an iodiuophilous vacuole in the sporoplasm. Mostly " free f °P m g °PP' h ' P. oPP From I.1nlester's Treatise on Zoology, vol. Protozoa, after Thelohan. a, Differentiation of the pansporoblast (p.sp). b, Pansporoblast with two nuclei. c and d, Pansporoblasts with six and ten nuclei respectively; in d, four of the nuclei are degenerating. e, Pansporoblast segmented into two definitive sporoblasts, each with three nuclei. In the next four figures the definitive sporoblast, or the spore produced from it, is alone figured. f, Definitive sporoblast segmented into three masses, the capsulogenous cells (c.g.c) and the sporoplasm (sp.p), e;idoth. From Lankester's Treatise on Zoology, vol. Protozoa. b, Buds. end, Endoplasm; the clear See also:outer portion re-presents the ectoplasm. parasites. Gen. Sphaerospora. Four or five species are known, from the kidneys or gall bladder of fishes (fig. 3, A). One, S. elegans, is interesting in that it affords a transition between the two sections, being disporous. Gen. Myxidium; spores elongated and fusiform, with a polar capsule at each extremity. The best-known species is M. lieberkiihnii, from the urinary bladder of the See also:pike. One or two species occur in reptiles. Other genera are Sphaeromyxa, Cystodiscus, Myxosoma and Myxoproteus. Family, Chloromyxidae. Spores with four polar capsules and no iodinophilous vacuole. One genus, Chloromyxum, of which several species are known; the type being C. leydigi, from the gall bladder of various Elasmobranchs (fig. 7, B). Family, Myxobolidae. Spores with two polar-capsules (exceptionally one), and with a characteristic iodinophilous vacuole in the sporoplasm. Typically tissue parasites of Teleosteans, often very dangerous. Genus Myxobolus. Spores See also:oval or rounded, without a tail-like process. Very many species are known, which are grouped into three subsections: (a) forms with only one polar-capsule, such as M. piriformis, of the See also:tench; (b) forms with two unequal capsules, e.g. M. dispar from Cyprinus and Leuciscus; and (c) the great majority of species with two equal polar-capsules, including M. miilleri, the type-species, from different fish, M. cyprini and M. pfeifferi, the cause of deadly disease in carp and barbel respectively and others. Other genera are Henneguya and Hoferellus, differing from Myxo- a B b From Lankester's Treatise on Zoology. vol. Protozoa. B. Spores of Chloromyxidae, after Thelohan. a, Chloromyxum leydigi, Ming., seen from the sutural aspect, X2250; b, C. caudatum, Thel., X 1900. p.c, Polar capsules; s, suture; f, filaments; p.s, tail-like process of the spore envelope. From Wasielewski's Sporozoenkunde. C. Spores of Myxobolus ellipsoides, Thel. The spores on the See also:left and right are lying with the sutural plane See also:horizontal, that in the See also:middle with the sutural plane vertical. bolus in having, respectively, one or two tail-like processes to the spore. Lentospora, according to Plehn (37), lacks an iodinophilous vacuole. Family Coccomyxidae. The pansporoblasts produce (probably) only one spore. Spore oval, large (14 pt by 5.5 µ), with a single very large polar-capsule. Sporoplasm with no vacuole. Single genus Coccontyxa, with the characters of the family. One species, C. morovi, Leger and Hesse, from the gall bladder of the sardine. The spore greatly resembles a Cryptocystid spore. Suborder 2: Cryptocystes, Gurley (=Microsporidia, Balbiani). Spores minute, usually See also:pear-shaped, with only one polar-capsule, which is visible only after treatment with reagents. The number of spores formed in each pansporoblast varies greatly in different forms. Section (a) : Polysporogenea. The trophozoite produces numerous pansporoblasts, each of which gives rise to many spores. Genus Glugea, with numerous species, of which the best-known is G. anomala, from the See also:stickleback (fig. I). The genus Myxocystis, which has been shown by Hesse (24) to be a true Microsporidian, is placed by Perez in this section, but this is a little premature, as Hesse does not describe the exact character of the sporulation, i.e. with regard to the number of pansporoblasts and the spores they produce. Section (b): Oligosporogenea. The trophozoite becomes itself the (single) pansporoblast. In Pleistophora, the pansporoblast produces many spores; P. typicalis, from the muscles of various fishes (fig. 2), is the type-species. In Thcloltania, eight spores are formed;the different species are parasitic in See also:Crustacea. In Gurleya, parasitic in Daphnia, only four are formed; and, lastly, in Nosema (exs, N. pulvis, from Carcinus, and, most likely, N. bombycis, of the See also:silk-See also:worm), each pansporoblast produces only a single spore. 2. Order—Actinomyxidia. This order comprises a See also:peculiar group of parasites, first described by A. Stoic in 1899, which are restricted to Oligochaete See also:worms of the family Tubificidae. Most forms attack the intestinal wall, often destroying its epithelium over consider-able areas; but one genus, Sphaeractinomyxon, inhabits the body-cavity of its host. The researches of Caullery and Mesnil (10-12) and of Leger (28 and 29) have shown that the parasites exhibit the typical features of the Endospora, and the spores possess the characteristic polar-capsules of the Myxosporidian spore, but differ therefrom by their more complicated structure. The growth and development of an Actinomyxidian have been recently worked out by Caullery and Mesnil in the case of Sphaeractinomyxon stolci. A noteworthy point is the differentiation of an See also:external (covering) cellular layer, which affords, perhaps, the nearest approach to distinct tissue-formation known among Protozoa. This envelope is formed soon after nuclear multiplication of the young trophozoite has begun, and is constituted by two nuclei and a thin, peripheral layer of cytoplasm. It remains binuclear throughout the entire period of development, and serves as a delicate cyst-membrane. The multiplication of the See also:internal nuclei is accompanied by a corresponding division of the cytoplasm; so that instead of a multinucleate or plasmodial condition, distinct uninucleate cellules are formed, up to sixteen in number. These cellules, as a See also:matter of fact, are sexual elements or gametes; and eight of them can be distinguished from the other eight by slight See also:differences in the nuclei. The gametes unite in couples, each couple being most probably composed of dissimilar members: in other words, conjugation is slightly anisogamous. Each of these eight copulae gives rise to a spore. As the name of the order implies, there are always eight spores formed. These differ from other Endosporan spores in having invariably a ternary symmetry and constitution (fig. 9). The wall of the spore is composed of three valves, each formed from an enveloping cell, and three capsular cells, placed at the upper or anterior pole, and containing each a polar-capsule, visible in the fresh condition. The valves are usually prolonged into processes or appendages, whose form and arrangement characterize the genus; but in Sphaeractinomyxon the spore is spherical and lacks processes. The sporoplasm maybe either a plasmodial See also:mass, with numerous nuclei, or may form a certain number of uninuclear sporozoites. A remarkable feature in the development of the spore is that the germinal tissue (sporoplasm) arises See also:separate from and outside the cellules which give rise to the spore-wall; later, when the envelopes are nearly developed, the sporoplasm penetrates into the spore. Four genera have been made known. (i) Hexactinomyxon, See also:Stole. Spores having the form of an See also:anchor with six arms; sporoplasm plasmodial, situate near the anterior pole of the spore. One sp. H. psammoryctis, from Psantmoryctes. (2) Triactinomyxon, St. Spores having the form of an anchor with three arms; distinct sporozoites, disposed near the anterior pole. T. ignotum, with eight spores, from Tubifex tubifex, and also from an unspecified Tubificid; another sp., unnamed, with 32 sporozoites, also from T. t. (3) Synactinomyxon, St. Spores See also:united to one another, each having two aliform appendages; sporoplasm plasmodial.' One sp., S. tubificis, from 7'. rivuloruan. (q) Sphaeractinomyxon, C. and M. Spores spherical, without aliform prolongations; sporoplasm gives rise to very many b d From Lankester's Treatise on Zoology, vol. Protozoa. various Glugeidae, x 1500 (after Thelohan). a and b, Pleistophora typicalis, Gurley; a in the fresh condition, b after treatment with See also:iodine See also:water, causing extrusion of the filament. e and d, Thelohania octospora, Henneguy; c fresh, d treated with See also:ether. e, Glugea depressa, Thel., fresh. f, G. acuta, Thel. up the endoplasm into somewhat angular See also:chambers or alveoli (fig. r 2). In each chamber is a pansporoblast, which divides up to produce many spores ;,hence the spores formed from different See also:pan- sporoblasts are kept more or less separate. The pansporoblasts originate, in a growing Sarcosporidian, at the two poles of the body, where the peripheral endoplasm with its nuclei is chiefly aggregated. More inter- nally, spore-formation is in progress; and in the centre, pansporoblasts full of ripe spores are found. By this See also:time the See also:para- site has greatly distended the muscle-fibre in which it has hitherto lain, ab- sorbing, with its growth, practically all the con- tractile-substance, until it is surrounded only by the From Lankester's Treatise on Zoology, vol. Protozoa. sarcolemma and sarco- a, Hexactinomyxon psammoryctis (par. Psammoryctes c, Triactinomyxon ignotum (par. Clitellio, sp.). the adjacent connective- barbatus). d, Upper portion of Hexactinomyxon, showing two tissue, and in this phase b, Synactinomyxon tubificis (par. Tubifex rivulorum) ; of the three polar capsules, one with filament has been distinguished the mass of united spores. discharged. from Miescheria as Bal- biania, under the impression that the two forms were quite distinct. In the later stages, the parasite may become more rounded, and a cyst may be secreted around it by the host's tissue. In these older forms, the most centrally placed spores degenerate and See also:die, having become over-ripe and stale. With regard to the spores themselves and what becomes of them, our knowledge is defective. Two kinds of reproductive germ have been described, termed respectively gymnospores (so-called sporozoites, " Rainey's corpuscles ") and chlamydospores, or simply spores. It seems probable that the former serve for endogenous or auto-infection, and the latter for infecting fresh hosts. Unfortunately, however, both kinds of germ are not yet known in the case of any one species. The gymnospores, sporozortes, occupying the whole spore. One sp., S. stolci, from Clitellio and Hemitubifex. 3. Order—Sarcosporidia. With the exception of one or two forms occurring in reptiles, these parasites are always found in warm-blooded Vertebrates, usually Mammals. They are of See also:common occurrence in domestic animals, such as pigs, See also:sheep, horses and (sometimes) See also:cattle. A Sarcosporidian has also been described from See also:man. The characteristic habitat is the striped muscle, generally of the See also:oesophagus (fig. ro, A) and See also:heart, but in acute cases the parasites overrun the general musculature. When this occurs, as often happens in mice, the result is usually fatal. Unless, however, the organisms thus apread throughout the body, the host does not appear to suffer any serious consequences. In addition to the effects produced by the general disturb- ance to the tissues, the attacked animals have apparently to contend —at any rate in the case of Sarcocystis tenella in the sheep—with a See also:poison secreted by the parasite. For Laveran and Mesnil (27) have isolated a toxine from this form, which they have termed sarcocystin. In the See also:early stages of growth, a Sarcosporidian appears as an elongated whitish body lodged in the substance of a muscle-fibre; this phase has long been known as a " Miescher's See also:tube," or Miescheria. The youngest trophozoites that have been yet observed (by See also:Bertram, 1) were multinucleate (fig. A), but there is no See also:reason to doubt that they begin life in a uninuclear condition. The protoplasm is limited by a delicate cuticle. With growth, organellae corresponding to the Myxosporidian pansporoblasts are formed by the segregation internally of little uninuclear See also:spheres of protoplasm. At the same time, a thick striated envelope is developed around the parasite, which later comes to look like a fur of See also:fine filaments. The probable explanation of this feature (given by Vuillemin, 44) is that it is due to the partial breaking down of a stiff, vertically (or radially) striated external layer (fig. r 2, A), such as is seen in Myxidium lieberkuhnii. Immediately internal to this is a thin, homogeneous membrane, thich sends numerous partitions or septa inwards; these divide A B After Bertram, from Wasielewski'sSporozoenkunde. which are the more commonly found (e.g. in S. muris, S. miescheriana of the See also:pig, and other forms), are small sickle-shaped From Wasielewski sSporozoenkunde. (FIG. io.—A. Sarcosporidia in the ox; a transverse section of the oesophagus, natural size, showing the parasites in the outer (a, b, c, d, e) and inner f. g, h) See also:muscular coats. B. See also:Longitudinal section of a muscle-fibre containing a Sarcosporidian parasite, X 6o. a k- or reniform bodies which are more or less amoeboid, and capable of active movement at certain temperatures. They appear to be naked, and consist of finely granular protoplasm, containing a single nucleus and one or two vacuoles. The chlamydospores, or From Wasielewski's Sporozoenkunde. B, Sarcocystis of the ox: section of a stage similar to fig. 12. a, Substance of muscle-fibre; b, envelope of parasite; c, nuclei of the muscle; d, parasitic germs (gymnospores); e, walls of the alveoli. In the peripheral alveoli are seen immature germs. true spores, occur in S. tenella of sheep (fig. 13), and have been described by Laveran and Mesnil (26). They also are falciform, but one extremity is rounded, the other pointed. There is a very thin, delicate membrane, most unlike a typical, resistant spore-wall; and the spores themselves are extremely fragile and easily acted upon and deformed by reagents, even by distilled water. The rounded end of the spore contains a large nucleus, while at the other end is an oval, clear space, which, in the fresh condition, shows a distinct See also:spiral striation. The exact significance of this structure has been much debated. In position and See also:appearance it recalls the polar-capsule of a Myxosporidian spore. The See also:proof of this See also:interpretation would be the See also:expulsion of a filament on suitably stimulating the spore; while, how-ever, some investigators have asserted that such a filament is extruded, this cannot be regarded as at all certain. Hence it is still doubtful whether this striated body really corresponds to a polar-capsule.
Nothing whatever is known as to the natural means by which infection with Sarcosporidia is brought about. See also: (= Miescheria+Balbiania, See also:Blanchard.) Some of the See also:principal species are: S. miescheriana, from pigs; S. tenella, fromsheep; S. bertrami, from horses; S. blanchardi, from Bovines; S. muris, from mice; S. platydactyli, from the See also:gecko; and lastly, S. lindemanni, described from man. 4. Order—Haplosporidia. The Sporozoa included in this order are characterized by the general simplicity of their development, and by the undifferentiated character of their spores. The order includes a See also:good many forms, whose arrangement and See also:classification have been recently undertaken by Caullery and Mesnil (15), to whom, indeed, most of our knowledge See also:relating to the Haplosporidia is due. The habitat of the parasites is sufficiently varied; Rotifers, Crustacea, Annelids and fishes furnishing most of the hosts. A See also:recent addition to the See also:list of Protozoa causing injury to man, a Haplosporidian, has been a, Yoang form with opaque,evenly-granulated protoplasm and few refringent granules; the nuclei (n) are small, and appear to be surrounded each by a clear space. b and c, Full-grown specimens with large nuclei and clearer protoplasm, containing numerous refringent granules (r.gr.). d and e, Morula stages, derived from b and c by division of the body into segments centred See also:round the nuclei, each cell so formed being a spore. Between the spores a certain amount of inter-cellular substance or residual described by Minchin and Fantham (29d), who have termed the parasite Rhinos poridium, from its habitat in the nasal septum, where it produces pedunculate tumours. Bertramia, a well-known parasite of the body-cavity of Rotifers, will serve very well to give a general idea of the life-See also:cycle so far as it has yet been made out (fig. 14). The trophozoite begins life as a small, rounded uninucleate corpuscle, which as it grows, becomes multinucleate. The multinuclear body generally assumes a definite shape, often that of a sausage. Later, the protoplasm becomes segregated around each of the nuclei, giving the parasite a mulberry-like aspect; hence this stage is frequently known as a morula. The uninuclear cellules thus formed are the spores, which are ultimately liberated by the break-up of the parent body. Each is of quite simple, undifferentiated structure, possesses a large, easily-visible nucleus, and gives rise in due course to another young trophozoite. In some instances, as described by a b (After Laveran and Mesnil, from Lankester's Treatise on Zoology, vol. Protozoa.) a, Spore in the fresh condition,showing a clear nucleus (n) and a striated body or capsule (c). b, Stained spore; the nucleus (n) shows a central karyosome; the striations of the polar capsule (c) are not visible. 4 e -eFrom Minchin, in Lankester's Treatise on Zoology, vol. Protozoa. C. f protoplasm is left, in which the refringent granules seem to be embedded. The morula may break up forth-with and scatter the spores, or may first round itself off and form a spherical cyst with a tough, fairly thick wall. Empty, slightly shrunken cyst, from which the spores have escaped. g, Free spore or youngest toil. cellular trophozoite. h, i, j, Commencing growth of the trophozoite, with multiplication of the nuclei, which results ultimately in forms such as a and b. f, Minchin, the sporulating parasite becomes rounded off and forms a protective cyst, doubtless for the See also:protection of the spores during dissemination. In some forms (e.g. Haplosporidium and Rhinosporidium) the spore-mother-cells, instead of becoming each a single spore, as in Bertramia, give rise to several, four in the first case, many in the latter. Sometimes, again, the spore, while preserving the essentially simple character of the sporoplasm, may be enclosed in a spore-case; this may have the form of a little See also:box with a lid or operculum, as in some species of Haplosporidium, or may possess a long process or tail, as in Urosporidium (fig. 15). The Haplosporidia are divided by Caullery and Mesnil into three families, Haplosporidiidae, Bertramiidae and Coelosporidiidae; one or two genera are also included whose exact position is doubtful. (a) Haplosporidiidae: 3 genera, Haplosporidium, type-species H. heterocirri; Urosporidium; with one sp., U. fuliginosum; all parasitic in various Annelids; and Anurosporidium, with the species A. pelseneeri, from the sporocysts of a Trematode, parasitic on Donax. b) Bertramiidae: 2 genera, Bertramia, with B. capitellae from an From Caullery and Mesnil, Archives de zoologie expirimenfale, vol. 4, 1905, by per-See also:mission of See also:Schleicher Freres et Cie, See also:Paris. 1, Haplosporidium heterocirri: 3, H. vejdovskii. a, on liberation; 4, Urosporidium fuliginosum: b, after being in See also:sea-water. a, See also:surface-view; 2, H. scolopli. b, See also:side-view. X See also:i000. Annelid and B. asperospora, the Rotiferan parasite above described; and Ichthyosporidium, with I. gasterophilum and I. phymogenes, parasitic in various fish. (c) Coelosporidiiae: genera Coelosporidiuni, type-species C. chydoriclola; and Polycaryum, type-species P. branchiopodianum. These forms are parasitic in small Crustacea. The genus Blastulidium is referred, doubtfully, by Caullery and Mesnil to this family.; but certain phases of this organism seem to indicate rather a See also:vegetable nature. The genus Rhinosporidium should probably be placed in a distinct family. The only species so far described is R. kinealyi from the nasal septum of man, to which reference has above been made. Another form, Neurosporidium cephalodisci, agreeing in some respects with Rhinosporidium, has been described by Ridewood and Fantham (37a) from the See also:nervous See also:system of Cephalodiscus. A parasite whose See also:affinities are doubtful, but which is regarded by Caullery and Mesnil as allied to the Haplosporidia, is the curious parasite originally described by Schewiakoff as " endoparasitic tubes" of Cyclops; it has been named by Caullery and Mesnil, Scheviakovella. This organism is remarkable in one or two ways: it possesses a contractile vacuole; the amoeboid trophozoites tend to form plasmodia; and the spores, of the usual simple type, may apparently divide by binary fission. 5. There remain, lastly, certain forms, which are conveniently grouped together as "Sporozoa incertae sedis," either for the reason that it is impossible to See also:place them in any of the well-defined orders, or because their life-cycle is at present too insufficiently known. Serosporidia is the name given by See also:Pfeiffer to certain minute parasites of the body-cavity of Crustacea; they include .Serosporidium, Blanchardina and Bolellus. Lymphosporidium, a form with distributed nucleus, causing virulent epidemics among See also:brook-See also:trout,is considered by Calkins(3) to be suitably placed here. Another parasite of lymphatic spaces and channels is the remark-able Lymphocystis, described by Woodcock (46), from See also:plaice and flounders, which in some respects rather recalls a Gregarine. The group Exosporidia was founded by Perrier to include a peculiar organism, ectoparasitic on Arthropods, to which thename of Amoebidium had been given by Cienkowsky. It has recently been shown, however, that this organism is most probably an Alga. Another genus, Exosporidium, described by See also:Sand (38), is placed at present in this group. For details of the structure of these forms and others like Siedleckia, Toxosporidium, Chitonicium Joyeuxella and Metschnikovella, a comprehensive treatise on the Sporozoa, such as that of Minchin, should be consulted. To See also:complete this See also:article, it will be sufficient to mention various enigmatical bodies, associated with different diseases, which are regarded by their describers as Protozoa. Among such is the Histosporidium carcinomatosum " of Feinberg, which he finds in cancerous growths. Cytoryctes, the name given to " See also:Guarnieri's bodies " in small-pox and vaccinia, has been recently investigated by Calkins (3a), who has described a complex life-cycle for the alleged parasite. Other workers, however, such as Siegel, give a quite different See also:account of these bodies, and, moreover, find similar ones in See also:scarlet-See also:fever, syphilis, &c.; while yet others (e.g. Prowazek) deny that they are parasitic organisms at all. 4 pls. ; (3b) M. Caullery and A. Chappellier, "Anurosporidium pelseneeri, (n.g., n.sp.), Haplosporidie," &c., C. R. See also:soc. biol. 6o, p. 325, Igoe.; (4) M. Caullery and F. Mesnil, "Sur un type nouveau" (Metchnikovella, n.g.), C. R. ac. sci. 125, p. 787, Io figs., 1897; (5) ib. " Sur trois Sporozoaires parasites de la Capitella," C. R. soc. biol. 49, p. 1005, 1877 ; (6) ib. " Sur un Sporozoaire aberrant " (Siedleckia, n.g.), op. Cit. 50, p. 1093, 7 figs., 1898 ; (7) ib. " Sur le genre Aplosporidium" (nov.), op. cit. 51, p. 789, 1899; (8) ib. " Sur See also:les Aplosporidies," C. R. ac. sci. 129, p. 616, 1899; (9) ib. " Sur les parasites intimes See also:des Annelides " (Siedleckia, Toxosporidium), C. R. See also:ass. See also:franc., 1899, p. 491, 1900; (10) ib. " Sur un type nouveau (Sphaeractinomyxon, n.g.) d'Actinomyxidies," C. R. soc. biol. 56, p. 408, 1904; (11) ib. Phenomenes de sexualite dans le developpement des Actinomyxidies," op. cit. 58, p. 889, 1905; (12) ib. " Recherches sur les Actinomyxidies," See also:Arch. Protistenk. 6, p. 272, pl. 15, 1905; (13) ib. " Sur quelques nouvelles Haplosporidies d'Annelides," C. R. soc. biol. 58, p. 58o, 6 figs., 1905; (14) ib. " Sur des Haplosporidies parasites de poissons marins," ib. p. 64o, 1905 ; (15) ib. " Recherches sur les Haplosporidies," Arch. zool. exp. (4) 4, p. 101, pls. 11-13, 1905; (16) L. Cohn, ' Ober die Myxosporidien von Esox See also:lucius," Zool. Jahr. Anat. 9, p. 227, 2 pls., 1896; (17) ib. " Zur Kenntniss der Myxosporidien," Centrbl. Bakt. 1, Orig. 32, p. 628, 3 figs., 1902; (18) ib. " Protozoen als Parasiten in Rotatorien," Zool. Anz. 25, p. 497, 1902; (19) F. Doflein, " Ober Myxosporidien," Zool. Jahr. Anat. Is, p. 281, 6 pls., 1898; (20) ib. " Fortschritte auf dem Gebiete der Myxosporidienkunde," Zool. Centrbl. 7, p. 361, 1899; (21) R. Gurley, " The Myxosporidia," See also:Bull. U.S. Fish. See also:Comm., 1892, p. 65, 47 pls., 1894; (22) E. Hesse, ' Sur une nouvelle Microsporidie tetrasporee du genre Gurleya," C. R. soc. biol. 55, p. 495, 1903; (23) ib. " Thelohania legeri " (n.sp.), op. cit. 57, pp. 570-572, 10 figs., 1904; (24) ib. " Sur Myxocystis Mrazeki Hesse," &c., op. Cit. 58, p. 12, 9 figs., 1905; (25) A. Laveran and F. Mesnil, " Sur la multiplication endogene des Myxosporidies," op. cit. 54, p. 469, 5 figs., 1902; (26) ib. Sur la morphologie des Sarcosporidies," op. Cit. 51, p. 245, 1899; (27) ib. " De la Sarcocystin," op. cit. p. 311, 1899; (28) L. Leger, " Sur la sporulation du Triactinomyxon," op. cit. 56, p. 844, 4 figs., 1904; (29) ib. " Considerations stir . les Actinomyxidies, ' op. cit. p. 846, 19041 (29a) L. Leger and E. Hesse, " Sur une nouvelle Myxosporidie, Coccomyxa, n.g.," C. R. ac. sci., 1st See also:July 1907; (29b) ib. " Sur la structure de la paroisporale des Myxosporidies," op. cit. 142, p. 720, 1906; (29c) A. Lutz and A. Splendore, " Ober 'Pebrine' and verwandte Mikrosporidien," Centrbl. Bakt. I, 33, Orig. p. 150, 1903, and 36, Orig. p. 645, 2 pls., 1904; (29d) E. A. Minchin and H. B. Fantham, Rhinosporidium kinealyi " (n.g., n.sp.), Q. J. Micr. Sci. 49, p. 521, 2 pls., 1905; (30) A. Mrazek, " Uber eine neue S orozoenform " (Myxocystis), S. B. Bohm. Ges. 8, 5 pp., 9 figs., 1897; (31) ib. "Glugea lophii," Doflein, op. cit. so, 8 pp., r pl., 1899; (32) C. Perez, " Sur un organisme nouveau, Blastulidium," C. R. soc. biol. 55, p. 715, 5 figs., 1903; (33) ib. " Sur nouvelles Glugeidees," op. cit. 58, pp. 146-151, 1905; (34) ib. " Microsporidies parasites des crabes," Bull. sta. biol. d'See also:Arcachon, 8, 22 pp., 14 figs., 1905 ; (35) W. S. Perrin, " Pleistophora periplanetae," Q. J. Micr. Sci. 49, p. 615, 2 pls., 1906; (36) L. See also:Plate, " Ober einen einzelligen Zellparasiten ' (Chitonicium), See also:Fauna Chilensis, 2, pp. 6o1, pls., 1901; (37) M. Plehn, " Uber die Drehkrankheit der Salmoniden " (Lentospora, n.g.), Arch. Protistenk. 5, p. 145, pl. 5, 1904; (37a) W. J. Ridewood and H. B. Fantham, Neurosporidium cephalodisci, n.g., n.sp.," Q. J. Micr. Sci. 51, p. 81, pl. 7, 1907; (38) R. Sand, " Exosporidium marinum " (n.g., 2 a n.sp.), Bull. soc. micr. beige, 24, p. r16, 1898;(39) T. Smith, " The See also:production of sarcosporidiosis in the See also:mouse," &c., J. Exp. Med. 6, p. I, 4 pls., 1901; (40) W. Stempel], " Ober Thelphania mulleri," Zool. Jahr. Anat. 16, p. 235, pl. 25, 1902; (41) ib. " Uber Polycaryum hranchiopodianum " (n.g., n.sp.), Zool. Jahrb. Syst. 15, p. 591, pl. 31, 1902; (42) ib. " Uber Nosema anomalum," Arch. Protistenk, 4, p. I, pls. 1-3, 1904; (43) P. Thelohan, " Recherches sur les Myxosporidies, Bull. sci. France belg. 26, p. too, 3 pls., 1895; (44) P. Vuillemin, " Le Sarcocystis tenella, parasite de I'homme," C. R. ac. sci. 134, p. 1152, 1902; (45) H. M. Woodcock, " On Myxosporidia in See also:flat fish," Proc. Liverp. Biol. Soc. 18, p. 126, pl. 2, 1904; (46) lb. " On a remarkable parasite " (Lymphocysiis), op. cit. p. 143, pl. 3, 1904. (H. M. Additional information and CommentsThere are no comments yet for this article.
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