Protosporangium: a New Genus of Protostelids*

Protosporangium is described as a new genus of the mycetozoan order Protosteliida, with 3 new species: P. bisporum, P. fragile , and P. articulatum . The genus is characterized by minute, mostly 2-4-spored sporangia borne on long, slender, flexuous stalks. The spores produce flagellate cells (typically 8 per sporangium) during germination. The trophic stage is holozoic and uninucleate to plurinucleate but never reticulate. Plurinucleate protoplasts segment into uninucleate (sometimes binucleate) prespore cells that culminate to form sporocarps in the manner characteristic of protostelids.     

A New Microsporangial Protostelid,Microglomus paxillus gen. and sp. nov.*

SYNOPSIS. Microglomus paxillus is described as a new genus and species of the subclass Protosteliida (Class Eumyceto-zoa). It has been isolated only once from casuarina bark collected in Oahu, Hawaii. The new organism is characterized by a uninucleate ameboid trophic stage that feeds on bacteria and by sporocarps with spike-like stalks terminated by microspo-rangia containing tetrads of ameboid protoplasts or thin-walled spores. No flagellate cells are produced. The tetrads are typically formed by successive bipartition following conjugate nuclear divisions in the sporogen. The cells of the tetrad are at first binucleate but soon become uninucleate as a result of nuclear degeneration. Variations in the process of sporogenesis are described.     

Uninucleate spores of Phycomyces

Summary Under most culture conditions only 0.3% of the vegetative spores of Phycomyces blakesleeanus are uninucleate. On an acidified minimal medium, the uninucleate fraction can be raised up to 4.5% of the spores. The spore population can be fractionated in a gradient under gravity (1xg) yielding fractions that contain over 80% uninucleate spores. These uninucleate spores are fully viable. When the spores to be fractionated are obtained from a heterokaryotic mycelium, the uninucleate fraction produces homokaryotic mycelia.     

Stempellia milleri sp. n. (Microsporida: Nosematidae) in the Mosquito Culex pipiens quinquefasciatus Say*

Stempellia milleri sp. n. was found in blood cells and the adipose tissue of field-collected larvae of Culex pipiens quinquefasciatus Say. Its development is different from other Stempellia species described in that it is dimorphic, producing two types of spores in adipose cells. Both were studied with the electron microscope. One spore is thin-walled and uninucleate; the other is thick-walled and binucleate. The latter spores are produced from sporonts that are somewhat similar to those of Nosema. Sporoblasts and spores of S. milleri were compared to those of Stempellia magna Kudo, and Stempellia lunata Hazard and Savage in both light and electron microscope preparations. S. milleri was transmitted experimentally to Culex pipiens pipiens, C. p. quinquefasciatus, C. salinarius, C. tarsalis, and C. territans. Transmission of S. magna to its host and other mosquito species was not possible. Although, generally low numbers of test larvae became infected with the pathogen, heavy infections were seen occasionally in individual specimens of its natural host, C. p. quinquefasciatus. Species of Aedes, Anopheles, Culiseta, Psorophora, and Uranotaenia exposed to spores of S. milleri were not susceptible to the disease.     

Congruence between larval ventromental plate ultrastructure and immature morphology in Yama Sublette & Martin and some Oceanian species of Chironomus Meigen (Diptera: Chironomidae)

The morphology of the larval ventromental plates of Y. tahitiensis Sublette & Martin and four Oceanian species of Chironomus Meigen, C. hawaiiensis Grimshaw, C. javanus Kieffer, C. magnivalva Kieffer and C. samoensis Edwards, has been studied by scanning electron micrography. Data on ventromental plate ultrastructure are used in phenetic and cladistic analyses of the relationships of T. tahitiensis and the Oceanian Chironomus to other species in Chironomus and additional genera. The results of these analyses support the current generic status of T. tahitiensis but indicate that Yama is less closely related to Chironomus than previously supposed, a finding that is supported by a reexamination of ‘traditional’ morphological features.     

Microsporidium goeldichironomi n. sp. and Microsporidium chironomi n. sp. (Microsporida: Apansporoblastina): Two new microsporidia from Florida chironomids

Two new species of Microsporida belonging to the genus Microsporidium are described. Microsporidium goeldichironomi n. sp. parasitizes the fat body of Goeldichironomus holoprasinus and Microsporidium chironomi n. sp. infects Chironomus attenuatus. Both microsporidia form uninucleate spores from rosette-shaped sporonts. M. goeldichironomi sporonts form 4, 6, 8, 10, 12, 16, and possibly more spores. Two shapes of spores are produced, oval, or slightly pyriform spores measuring 3.70 ± 0.09 × 2.49 ± 0.13 μm and pyriform spores measuring 3.74 ± 0.44 × 2.04 ± 0.17 μm. Electron micrographs show that both types of spores are uninucleate, have 8 to 11 polar filament coils and a lamellate polaroplast showing several distinct regions. M. chironomi spores are pyriform and are often joined at the posterior end in groups of two or four. They measure 4.12 ± 0.37 × 2.45 ± 0.26 μm. The spores are uninucleate, have six to seven polar filament coils and a lamellate polaroplast showing two distinct regions. Neither species can be transmitted per os and thus are assumed to be transovarially transmitted. No pansporoblastic membrane is present in either species.     

Salsuginus neotropicalis n. sp. (Monogenea: Ancyrocephalinae) from the pike killifish Belonesox belizanus (Atheriniformes: Poeciliidae) from southeastern Mexico

Salsuginus neotropicalis n. sp. is described from the gills of Belonesox belizanus (Kner), the pike killifish (Poeciliidae), from the southeastern Mexico. S. neotropicalis is distinguished from all other congeners by the morphology of the haptoral sclerites, especially by the presence of a ventral bar with notably enlarged ends, and by possessing overlapping gonads. The diagnosis of Salsuginus is amended based on the position of gonads in this species. This is the first known Salsuginus species occurring in a freshwater fish from the Neotropical Region.     

Intracellular Development of the Microsporidan Glugea anomala Moniez in Hypertrophying Migratory Cells of the Fish Gasterosteus aculeatus L., an Example of the Formation of "Xenoma" Tumors

SYNOPSIS. The conclusion drawn in 1921 that the large nuclei in the cytoplasmic cortex of Glugea cysts are not vegetative nuclei of the microsporidan but nuclei of the hypertrophied host cell was based on the discovery of early developmental stages in the mesenchyme of stickleback larvae experimentally fed Glugea spores. This observation had been made on serial sections from experiments done in 1912. The intracellular development of the microsporidan could be followed up in this material only thru the 1st stages of schizogony. Renewed infection experiments, done still in 1921 on a much broader basis, have fully confirmed the previous findings, as briefly stated in 1922. On this material, the intracellular development of G. anomala has been followed up in recent years from uninucleate host cells 7 μ in diameter, interpreted as wandering cells in the mesenchyme, until they became macroscopic multinucleate cysts, in which schizogony and sporogony of the microsporidan produced innumerable vegetative stages and spores of Glugea. The details of the developmental processes are described in the present paper.
The multinucleate host cell and the intracellular parasites together form one of the symbiotic complexes for which the term "xenom" or "xenoma" has been used by me since 1949. By a sequence of amitotic nuclear divisions, the uninucleate host cell in the Glugea xenomas of Gasterosteus becomes plurinucleate in contrast to the usual structure of other xenomas of fish.
Already in 1921, I thought that the host cell in the Glugea xenomas may have phagocytic properties. The observation of accumulation of granules from pigment cells in some of the Glugea xenomas has now verified this supposition.     

Vairimorpha invictae N. Sp. (Microspora: Microsporida), a Parasite of the Red Imported Fire Ant,Solenopsis invicta Buren (Hymenoptera: Formicidae)12

ABSTRACT. Vairimorpha invictae n. sp. infects the red imported fire ant, Solenopsis invicta Buren, in Brazil. The parasite is dimorphic, producing two morphologically distinct types of spores, which develop sequentially in the same fat cells or oenocytes in the fat body. The binucleate free spores develop from disporous sporonts; the uninucleate octospores develop from multinucleate sporonts within a sporophorous vesicle. Infected cells are transformed into large sacs which contain both types of spores in mature adult hosts. Mature free spores are often present by the time the larvae pupate, but mature octospores are found only in adult hosts. Masses of spores may be seen through the intact cuticle by low power phase-contrast microscopy; there are no other physical signs and no behavioral signs of infection. Attempts to transmit the infection in the laboratory failed.     

Life Cycle of Culicospora magna (Kudo, 1920) (Microsporida: Culicosporidae) in Culex restuans Theobald with Special Reference to Sexuality1

The life cycle of Culicospora magna (Kudo, 1920) Weiser, 1977, consists of two major developmental sequences that alternate in host individuals of successive generations, each of the sequences starting with a sporoplasm and ending with spores. The first sequence occurs in larval, pupal, and adult stages of a parental generation of the host mosquito, Culex restuans Theobald; it begins with a sporoplasm from an ingested uninucleate spore and progresses through stages in gametogony, plasmogamy, nuclear association, merogony, karyogamy, and disporous sporulation with production of binucleate spores that discharge sporoplasms into the oocytes. The second sequence occurs in egg and larval stages of a filial generation of the same host species; it begins with the binucleate sporoplasm that entered the egg, includes stages in merogony, nuclear dissociation, and mictosporous sporulation, and ends with uninucleate spores. These spores are released into the environment following death of the host and are capable of infecting new parental generation host individuals. The life cycle is conceived as an alternation of generations related to haploidy and diploidy in the nuclei, the transition from haploidy to diploidy occurring with nuclear association and the transition from diploidy to haploidy occurring with nuclear dissociation.     

MORPHOLOGY OF CHAETOMIUM ERRATICUM

Development of perithecia from single, uninucleate ascospores disclosed a homothallic condition for Chaetomium erraticum. This species was found to produce sessile ascogonial coil initials from uninucleate vegetative cells that become enveloped by hyphae formed at the base of the ascogonium. The ascogonium consists of several cells that are uninucleate or binucleate. A perithecium forms from numerous divisions and enlargement of the surrounding uninucleate cells. Differentiation of the perithecial cells results in the formation of a carbonaceous wall, perithecial hairs, and an ostiole lined with periphyses. A convex hymenial cluster of ascogenous cells forms in the lower half of the centrum from which typical croziers develop. Asci push up into the pseudoparenchyma cells of the centrum. The growth of the ascogenous system is in part responsible for increase in perithecial size. The breakdown of the pseudoparenchyma cells around the developing asci results in the formation of a central cavity in which ascospores are released when the asci deliquesce. No paraphyses are present. The type of development and features of the centrum of C. erraticum and other species of Chaetomium indicate a distinct Xylaria-type centrum.     

Norlevinea n. g., a New Genus for Glugea daphniae (Protozoa: Microspore), a Parasite of Daphnia longispina (Crustacea: Phyllopoda)1

ABSTRACT. Norlevinea n. g. is established for microsporidia in which a uninucleate meront changes into a sporont by secreting a thin, membranous, sporontogcnetic and fragile sporophorous vesicle (pansporoblast membrane) in which four uninucleate sporoblasts are formed. In contrast to the genus Gurleya, the sporoblasts and later the spores are permanently joined into doublets, being laterally cemented by an electron-dense substance structurally identical to and continuous with the exospore layer. The polar filament is of the anisofilar type. The type species is Norlevinea daphniae (Weiser, 1947) n. comb., a parasite of the ovaries of Daphnia longispina occurring in several carp ponds in Czechoslovakia.     

Ultrastructure and Description of a New Species of Telomyxa (Microspora: Telomyxidae) from the Semiaquatic Beetle,Ora texana Champ. (Coleoptera: Helodidae)1

A new species of the uncommon microsporidian genus Telomyxa (Microspora: Telomyxidae) has been found parasitizing the larval fat body of the semiaquatic beetle, Ora texana. In this species, the sporogonic sequence results in the formation of sporocysts measuring 7.7 times 6.5 μm that contain two crested uninucleate spores (averaging 5.7 times 2.2 μm). The spores are essentially oblong/ovate, tapering toward the anterior end and remaining bound together after sporogony by a persistent accessory membrane or sporocyst. The two spores in the sporocyst are produced by an unusual morphogenetic sequence in which, after one mitosis, the binucleate sporont elongates, forming two lobes that fold toward one another and cleave along a central plane, forming two parallel sporoblasts. The general ultrastructural features of this process are described, and diagnostic characters of this new species of Telomyxa are presented.     

A new microsporidian parasite of the mosquito Aedes taeniorhynchus

A new species of microsporidium is described from the mosquito Aedes taeniorhynchus. This microsporidium is vertically transmitted and exhibits dimorphic development with one sequence leading to formation of short pyriform, uninucleate spores in male fourth instar larvae, pupae, and adults, and the other sequence leading to formation of diplocaryotic stages and cylindrical spores in adult females. Vertical transmission is apparently limited to a single generation, and the uninucleate spores are not transmissible per os to larvae.     

Über einen intrazellulären Parasiten beiCryptomonas (Cryptophyceae), II.

A new intracellular parasite inCryptomonas spp. div. previously known is described asProteromonas steinii spec. nova. The flagellate (infectious) stage isBodo-like, with a distinct kinetoplast. The immobile parasitic stage occurs in the cells of Cryptomonads as a multinucleate trophocyst with a thin mucilage envelope (pseudocyst), while the hypnocyst is uninucleate, walled and bearing two horned projections.

     

The Ultrastructure of Spores (Protozoa: Microsporida) from Lophius americanus,the Angler Fish1

ABSTRACT. Spinal and cranial ganglia of American angler fish, Lophius americanus, are often infected with microsporidia. This protozoon elicits the formation of large, spore-filled, hypertrophied host cells, cysts. Previous reports of microsporidia in European lophiids identify the parasite as Spraguea lophii, a genus which has recently been shown to be dimorphic. The spores from L. americanus are monomorphic (2.8 × 1.5 μm) and uninucleate. Each spore contains a polar tube that forms six to nine coils. Spraguea lophii differs from the microsporidium described in L. americanus in several ways. Spraguea lophii has two spore types: a large spore (4.0 × 1.25 μm) containing a diplokaryon and three to four polar tube coils and a smaller uninucleate spore (3.5 × 1.5 μm) with five to six polar tube coils. Because of these major differences, the microsporidium from L. americanus is removed from the genus Spraguea and returned to its original genus, Glugea, as a new species, G. americanus n. sp. Other ultrastructural characteristics of G. americanus are included: the posterior vacuole encloses two distinct membranous structures; one is tubular and resembles a “glomerular tuft” and the second is lamellar and composed of concentric membrane whorls, additionally, the straight or manubroid portion of the polar tube proceeds beyond the posterior vacuole before it turns anteriorly and begins to coil.     

Genetic divergence in Northamerican freshwater planarians of the Dugesia dorotocephala group (Turbellaria, Tricladida, Paludicola)

The genetic differentiation between the members of the Dugesia (Girardia) dorotocephala group was analyzed by means of multilocus electrophoresis, and comared to that of another planarian secies, D. tahitiensis, also belonging to the subgenus Girardia. The species examined were: D. dorotocephala s.s (2n = 16), D. arizonensis (2n = 8), D. jenkinsae (2n = 8), and the above mentioned D. tahitiensis (2n = 16). The former three species inhabit North America, and show different proportion of fissiparous and sexual individuals; the latter species inhabits Polynesia and is fully asexual. A total of 11 enzyme loci were genetically analyzed: Mdh-1, Mdh-2, Zdh-1, Idh-2, G3pdh, Got-1, Ck, Pgm-2, Ada, Mpi, and Gpi. Low values of observed mean heterozygosity per locus (Ho) were found in the populations studied, ranging from 0 to 0.18 (average 0.08. In asexual populations (except that of D. tahitiensis) fixed heterozygosity was observered in all the individuals for 1 or 2 loci. The genetic divergence between the species examined is very high, with many loci showing discriminating alleles in different taxa (Nei's genetic distance varies from 0.871 to 1.759). The populations of D. dorotocehala s.s., on the contrary, appear to be genetically quite homogenous average D= 0.019), and the genetic distance values are apparently unrelated to their geographic location and to their way of reproduction. The genetic distance between D. tahitiensis, a species not included in the D. dorotocephala group and D. dorotocephala s.s. is 1.314 and hence similar to the D value between two members of;he dorotocephala group: D. dorotocephala and D. jenkinsae (D = 1.303). The genetic relationships among the populations studied were established by UPGMA cluster analysis and multidimensional scaling. The descendence of the North American species with 2n = 8 from a dorotocephala-like ancestor with 2n = 16 is considered. It is suggested that the latter, as well as a tahitiensis-like line, also having 2n = 16, have originated from a common ancestor by geographic isolation.     

The effect of colchicine on colony formation in the algae Hydrodictyon,Pediastrum and Sorastrum

Summary Uninucleate, biflagellate zoospores of Hydrodictyon, Pediastrum and Sorastrum, derived from multinucleate parental cells, aggregate and adhere to form distinctively patterned colonies; earlier work has shown that microtubules underlie the plasmalemma of these zoospores and are also conspicuous in the developing horns of aggregating cells of Pediastrum and Sorastrum. Colchicine applied to parental cells inhibited cytoplasmic cleavage and production of uninucleate zoospores. When zoospores were treated with colchicine, their peripheral microtubules disappeared; the spores failed to aggregate in ordered arrays and did not develop horns. The microtubules therefore appear to play an important role in determining the arrangement of cells in developing colonies by affecting the shape of the cells at the time of their aggregation.     

On some species ofMycogloea

Three new species ofMycogloea are described and illustrated; they are:M. amethystina from Canada,M. nipponica, from Japan, andM. bullata from Thailand.Mycogloea tahitiensis is reported from Japan and additional undescribed taxa in the genus are briefly noted. Some characteristics of the genus are discussed, and a key is provided for six species recognized at this time.     

THE GENUS PROTOSTELIUM

Olive , L. S. (Columbia U., New York, N. Y.) The genus Protostelium . Amer. Jour. Bot. 49(3): 297–303. Illus. 1962.—Two new species of this simplest genus of the cellular slime molds are described: P. fimicola , a species with spherical spores and gelatinizing stalks occurring on dung, and P. arachispora , an elongate-spored species from dead plant material. The first has been found in North Carolina and the West Indies, while the second species has been found only once in North Carolina. Protostelium mycophaga var. major , from Connecticut, has distinctly larger spores than the original species. Further data on the distribution and development of P. mycophaga are presented. The genus is transferred to a family of its own, the Protosteliaceae .