ALBERT

Notes: Pore-forming activity in planar lipid bilayers and liposomes of extracts from differentially pathogenic Entamoeba and the-capacity of trophozoites and subcellular fractions to lyse human red blood cells (hrbc) were investigated. In all amebas studied, the two activities paralleled each other. They were high in E. histolytica irrespective of the virulence of the particular strain, but low in non-pathogenic E. histolytica-like amebas of human origin as well as in E. invadens, which is pathogenic for reptiles, and in E. moshkovskii isolated from sewage. We conclude that the capacities to insert pores and to lyse are not sufficient for virulence although they may be necessary.The subcellular distribution of the hemolytic activity of E. histolytica and its sensitivity to a variety of inhibitors and activators differ from those of other known amebic cytotoxic activities including pore formation. Therefore, there may be an additional constituent of E. histolytica involved in the cytotoxicity of the parasite.

Notes: The two unit membranes which envelope the endosymbiont of the trypanosomatid protozoon, Blastocrithidia culicis, were studied using the freeze-fracture technique. The distribution of the intramembranous particles on both fracture faces of the inner and outer membrane of the endosymbiont was analyzed in the replicas. The protoplasmic face of the inner membrane (PFi) had a higher density of membrane particles than that observed on the extracellular face (EFi), a pattern typical of plasma membranes. The extracellular face of the outer membrane (EFo) presented a density of membrane particles much higher than that observed on the P face of the outer membrane (PFo) a distribution significantly different from that found in the inner membrane of the endosymbiont and in the plasma membrane of the protozoon, but similar to that observed in Gram-negative bacteria. The data obtained support the idea that the endosymbiont of trypanosomatids represents a Gram-negative bacterium-like microorganism enveloped by two unit membranes and lacking a peptidoglycan layer and which lives in direct contact with the cytoplasm of the protozoon.

Notes: Paramecium caudatum syngen 3 could not reproduce in the defined medium (DM) which had been developed for P. octaurelia stock 299, but we succeeded in culturing it in DM supplemented with glycogen. The number of food vacuoles which formed in 5 and 10 min at 25°C in the DM alone was greater in comparison with the DM supplemented with glycogen. These results showed that the high molecular weight substance which needed to be added to a defined medium for the cultivation of Paramecium did not always support cell reproduction by stimulating food vacuole formation.

Notes: Ribosomes from Trypanosoma brucei rhodesiense and from Leishmania infantum were isolated and optimal conditions for in vitro translation were established. The effect of ribosome-inactivating proteins extracted from several plants was then assessed in order to identify those suitable for the preparation of immunotoxins against these organisms. Ribosomes from both species were inactivated by some ribosome-inactivating proteins (dianthins, saporins, pokeweed antiviral proteins, and the ribosome-inactivating chain of abrin). The similarity of the effects on the ribosomes from the two species examined indicates that ribosome-inactivating proteins should also be effective in a similar way on ribosomes from other species of Trypanosoma and Leishmania.

Notes: The Euplotes cytoskeleton obtained by treatment with Triton X-100 in a microtubule-stabilizing buffer has been studied by electron microscopy and SDS-polyacrylamide electrophoresis. An antiserum has been prepared using the tubulin band from preparative gels of Euplotes cytoskeletons as an antigen. This antiserum reacts with the tubulin from different ciliated protozoa but fails to recognize the vertebrate tubulin by immunoblotting. Immunoblotting studies have demonstrated a slower electrophoretic mobility for the α-tubulin of Euplotes and Oxytricha than that of Paramecium and Tetrahymena. A cytoplasmic microtubular network in Euplotes has been revealed by indirect immunoftuorescence using both an anti-α-tubulin monoclonal antibody directed against chick brain tubulin and an antiserum raised against the tubulin of Euplotes.

Notes: Some physical and chemical properties of DNA isolated from the dinoflagellate Woloszynskia bostoniensis were determined. Analytical cesium chloride gradient centrifugation gave a major component and a minor component banding at 1.719 and 1.693 g/cm, respectively. Thermal denaturation in 0.1 SSC showed a broad transition with a Tm of 70.5° C. Derivation of this curve indicated that two components were present having Tm values of 66° C and 70° C. Base composition analysis showed a GC content of 48.1% and a high degree of thymine replacement by 5-hydroxymethyluracil. Two minor bases, identified as 5-methylcytosine and N6-methyladenine, were also detected. Reassociation kinetics showed a typical eukaryotic reassociation pattern with 45% repetitive and 55% single copy sequences.

Notes: . Cysts of Giardia microti, isolated from feces and intestinal contents of Microtus ochrogaster, were examined by light and electron microscopy. These cysts differed morphologically from cysts of other G. duodenalis morphological types in that these cysts often contained two apparently differentiated trophozoites with mature ventral discs. Cysts more closely resembling those reported for G. lamblia and G. muris were in greater abundance in preparations made from intestinal contents and were interpreted as immature cysts. “Multiple fission” cysts, reported in G. muris and G. microti by earlier workers, were not observed; however, endosymbiotic bacteria were found in the cysts of G. microti and may have been responsible for reports of multiple fission in the cysts of Giardia.

Notes: . Lagenophrys anticthos n. sp. resembles L. aegleae Mouchet-Bennati; however, the two species are distinguished from one another by differences in the structure of the lorica aperture. Similarities in the shape of the lorica and macronucleus indicate a close phylogenetic relationship between L. anticthos and L. aegleae. The size of L. anticthos varies greatly within a population, and it is unclear whether this can be attributed to genetic differences or to environmental factors. In L. anticthos, variation in the form of the lips of the lorica aperture is correlated with variation in size. The brown, iron-rich incrustations observed around the loricae of L. aegleae by an earlier worker were not seen, indicating that the incrustations do not play a role in the symbiosis between L. aegleae and its host as was previously thought.

Notes: We report a method that allows us to grow and maintain the freshwater ciliate Euplotes octocarinatus in large quantities. Frequent exchange of culture fluid proved more effective than aeration in obtaining high cell densities (4200 cells/ml) and reasonable doubling times in large-scale cultures. For harvesting gamone 1, the cell density was raised to 10,000 cells/ml. Under these conditions, the cells continued to produce and secrete gamone; they were slightly starved, but they no longer divided. Cell-free fluid with a steady and relatively high yield of gamone was obtained from two such cultures over a period of five months. We isolated gamone 1 also from cell homogenates and compared it with secreted gamone 1, but found no differences in the gamones from these two sources.

Notes: Because heavy branchial infestations are thought to interfere with respiration, we examined the attachment of three stalked ciliates commonly found in the branchial chambers of Louisiana crawfish. Attachments by Cothurnia sp., Epistylis sp. and Acineta sp. differ in their fine structure. Stalks of the peritrichous ciliates. Cothurnia and Epistylis, contain striated tubules that differ in their arrangement, diameter, and in the periodicity of their striations. In both species the striated tubules branch within the basal disk and attach to a pad of adhesive material secreted by the organism during initial attachment to the gill surface. The stalk of the suctorian Acineta is composed of a striated honeycomb-like matrix. Within the basal disc the matrix is disorganized; however, striated elements anchor the stalk to a pad of adhesive material. Attachment sites also differ in the amount of secretory material deposited. Cothurnia forms a multi-layered, granular pad; Epistylis forms an indistinct, microfibrillar layer, and Acineta deposits a thick mucoid pad. None of the ciliates appear to damage the gill epicuticle nor is there an obvious host response. Harmful effects are probably limited to a decrease in respiratory surface area and disruption of normal water flow patterns. This may impair respiration sufficiently to increase the susceptibility of crawfish to low dissolved oxygen concentrations encountered periodically in commercial crawfish ponds.

Notes: Leucocytozoon caulleryi sporozoites that had been stored at - 196° C or -80° C for 6 or 12 months in Eagle's minimum essential medium or Medium 199 supplemented with 5% glycerol and 10% chicken serum showed infectivity to chickens. Glycerol at a concentration of 10% and dimethyl sulfoxide at 10% and 5% were found to be ineffective cryoprotective agents for the low temperature preservation of sporozoites. Sporozoites isolated from the intact females of Culicoides arakawae, which had been stored at -80° C for 6 or 12 months without cryoprotective agents, retained their infectivity. No differences were observed in the prepatent period, duration of parasitemia, and presence of serum-soluble antigens between chickens infected with frozen sporozoites and those infected with fresh sporozoites.

Notes: Two methods (manual and automated) for quantitation of viable versus dead Encephalitozoon cuniculi are reported. The manual method uses ethidium bromide and acridine orange to stain dead and viable organisms, respectively. The stained organisms are visually differentiated with the aid of a fluorescence microscope. The automated method uses propidium iodide to stain dead parasites, which are differentiated from viable unstained parasites with the aid of a flow cytometer. An automated cell counter (Coulter Counter) was used to count rapidly large numbers of samples and to improve the sensitivity of counting low concentrations of parasites. These methods will enhance investigators' abilities to conduct quantitative experiments on host defense mechanisms against E. cuniculi.

Notes: A total of 169 cross-transmission attempts has been made with 44 (11.8%) of the 372 named species of Eimeria of rodents. Of these, 161 were rodent-to-rodent, 6 rodent-to-lagomorph, and 1 each rodent-to-carnivore and rodent-to-bird. None of the last three categories was successful. In the rodent-to-rodent combinations, 39 (80%) of the 49 attempts to transmit a coccidian species from one rodent species to another of the same genus were successful, and only 14 (12.5%) of the 112 attempts to transmit a coccidium to a rodent of a different genus were successful. Eight of the successful attempts were with E. chinchillae, which was the only truly euryxenous species of Eimeria in the group. Two successful attempts were between the closely related rodent genera Spermophilus and Cynomys, and two were both of E. separata from Rattus norvegicus to some genetic strains but not to others of Mus musculus. One attempt with E. vermiformis from Mus musculus to Rattus norvegicus required treatment of the rat with the immunosuppressant dexamethasone to succeed. More cross-transmission studies are needed to determine the host-spectra of the species of Eimeria and other coccidian genera, and to determine the roles of genetics and immunosuppression in their transmission.

Notes: Cortical morphogenesis during excystment in Histriculus similis has been studied by light microscopy of preparations impregnated with silver proteinate (protargol). This morphogenesis shows clear differences from cortical morphogenesis during division. The oral, paroral, and fronto-ventro-transverse primordia originate from an extensive field of kinetosomes. The marginal cirral primordia and the dorsal bristle primordia appear at an early stage of morphogenesis. The left marginal cirral primordium originates from the oral primordium.

Notes: Using restriction enzyme analysis, mitochondrial DNA fragment patterns from seven strains of pathogenic and nonpathogenic Naegleria and one strain of Vahlkampfia were compared to estimate nucleotide sequence divergence. Significantly high levels of estimated genetic variation between strains of N. gruberi, N. fowleri, and N. jadini support the current taxonomic level of the individual Naegleria species and suggest a distinct phylogeny for each group. Naegleria lovaniensis, strain TS, was shown to have significant nucleotide sequence homology with N. gruberi, strain EGs, suggesting that the two groups share a close taxonomic relationship. The pathogenic strain MB-41 of N. fowleri exhibited distinct genetic divergence from the highly homologous, pathogenic strain Nf66 and the drug-cured strain 6088. Morphologically distinct strains EGs and 1518/la of N. gruberi exhibited significantly large sequence divergence consistent with a more distant taxonomic relationship. Amoebae from the genus Vahlkampfia expressed genetic similarity with strains of N. gruberi.

Notes: Bodo saltans was isolated from a chalk stream and fed with pure cultures of seven bacteria obtained from the same river. The flagellates were allowed to migrate into suspensions of either of two bacterial species in a T-maze at 20–22°C. There was a significant difference (P 〈 0.01) between the numbers of flagellates which migrated into suspensions of different bacteria, which were subsequently arranged in an order of “attractiveness” to the flagellate. Bodo saltans grew successfully in monoxenic suspensions of all seven bacterial strains, but more rapid growth occurred with non-flagellated than with flagellated bacteria; this may be because while feeding, B. saltans tends to associate with surfaces where non-flagellated bacteria may also congregate. The efficiency with which B. saltans is able to utilize different bacteria may be influenced by the motility or secretory activities of the bacteria. There was no incontrovertible evidence that B. saltans responds to specific bacterial attractants.

Notes: Thirteen eastern moles, Scalopus aquaticus, collected in West Texas were examined for coccidian oocysts; 11 (85%) were infected and eight (73%) of these had multiple infections representing two or more species. One cyclosporan, three eimerians, and two isosporans were studied and all are described as new species. Sporulated oocysts of Cyclospora megacephali n. sp. were subspheroidal, 18.5 × 15.7 (14–21 × 12–18) μm; they had sporocysts pointed at one end with Stieda bodies nearly as wide as the sporocysts themselves, and were 15.0 × 7.2 (11–17 × 6–9) μm; C. megacephali was found in four (31%) hosts. Sporulated oocysts of Eimeria scalopi n. sp. were spheroidal to subspheroidal, 13.6 × 12.6 (11–17 × 11–15) μm with sporocysts lemon-shaped, 8.7 × 5.5 (7–10 × 4–7) μm; it was found in six (46%) hosts. Sporulated oocysts of Eimeria aquatici n. sp. were asymmetrically ellipsoidal, 17.0 × 10.6 (14–20 × 9–14) μm, with sporocysts elongately ovoidal, 9.0 × 5.2 (8–11 × 4–6) μm; it was found in two (15%) hosts. Sporulated oocysts of Eimeria motleiensis n. sp. were subspheroidal, 17.0 × 15.3 (15–20 × 13–18) μm with sporocysts ovoidal, 10.7 × 6.8 (10–13 × 6–8) μm; it was found in seven (54%) hosts. Sporulated oocysts of Isospora motleiensis n. sp. were spheroidal to subspheroidal, 13.6 × 12.0 (10–17 × 8–15) μm with sporocysts broadly ovoidal, 9.5 × 6.7 (7–11 × 4–8) μm; it was found in nine (69%) hosts. Sporulated oocysts of Isospora aquatici n. sp. were subspheroidal, 20.9 × 18.4 (15–24 × 13–21) μm with sporocysts ellipsoidal, 11.8 × 9.0 (9–14 × 7–11) μm; it was found in two (15%) hosts.

Notes: Irradiation with X rays, UV irradiation after incorporation of bromodeoxyuridine (BU) into the DNA, and cis-platinum (cis-Pt) treatment each cause the loss of micronuclei of Stylonychia lemnae while the macronuclei are not severely affected. The abilities of both nuclei to repair DNA were investigated. Unscheduled DNA synthesis could not be demonstrated after X-ray irradiation, but it was found after treatment with BU/UV and cis-Pt in macro- and micronuclei. The extent of the repair process in the micro- and macronuclei was alike, as indicated by grain counts of [6-3H]thymidine-treated cells. One reason for the different sensitivity of both nuclei to DNA-damaging treatment may be the different number of gene copies in the macro- and micronuclei.

Notes: Trichocysts of Pseudomicrothorax dubius were ejected by 15% ethanol in phosphate-buffered culture medium (CM) and purified on discontinuous sucrose gradients, in which they concentrated in the lower part of the 27% phase and in the 57% phase. These phases were washed by 15% ethanol in CM, or by CM alone, and pooled. Ejected trichocysts observed by Nomarski interference contrast microscopy and after negative-staining for electron microscopy show a shaft with periodic cross-bands and four opened-out arms, sometimes with electron-dense droplets at both ends of each arm. On SDS-PAGE, trichocysts show ˜20 protein bands. The major bands are at 31 and 30 kD (G1), 27 and 26.5 kD (G2), 25 kD, 23 kD, and six bands at 15–20 kD (G3). Minor bands are observed above 30 kD, among them ciliary components which contaminate the trichocyst fraction. The trichocyst banding pattern was reproducible with different ejection media; however, the 30 kD disappeared when the buffered ejection medium contained no added Ca2+ or contained EDTA. When the trichocyst extract is solubilized in sample buffer without 2-mercaptoethanol, the major trichocyst bands are those of G1 and bands at 32.5–35 kD and 41 kD, which appear to be dimers of a few of the G3 proteins. On two-dimensional gels of trichocysts, ˜40 acidic protein spots are resolved with pI's of 4.6–6.6. On Western blots of two-dimensional gels, glycoproteins were revealed by Concavalin A-peroxidase labeling in three spots of G3, in two spots at 23 kD, in all five spots of G1, and in seven spots over 35 kD.

Notes: Goussia girellae n. sp. is described from the opaleye fish, Girella nigricans. Merogonic stages were observed in the apices of intestinal epithelial cells, in the lamina propria, and in extra-intestinal sites including liver, gills, and spleen. Gamonts were observed in the intestinal epithelial cells. Only unsporulated oocysts were detected in the intestine, and sporulation occurred when feces containing oocysts were incubated for 48 h in seawater at 21°C. Oocysts are elongated (24.8 × 14.7 μm) with a wall about 200 nm thick and have no residuum, micropyle, or polar granule. Sporocysts are ellipsoid (8.5 × 4.5 μm), have a thin two-layered wall approximately 30 nm thick, and consist of two valves joined by a suture. Although moribund opaleye were also infected with Gyrodactylus sp., Cryptobia sp., Cardicola sp., and epitheliocystis organisms (chlamydia), all fish were heavily infected with G. girellae and morbidity was thus attributed to the coccidium.

Notes: Trimyema compressum is a species included in the family Trimyemidae with the single genus Trimyema. This species has 50–60 somatic kinetics and three rows of kinetosomes surrounding the oral cavity. Two isolated groups of kinetosomes can also be observed on the right side of the oral region. The morphogenesis of bipartition is telokinetal; all the new infraciliary structures of the opisthe come from the longitudinal and postero-anterior proliferation of the last kinetosome of all the somatic kinetics. In the proter there is a reorganization of the oral infraciliature.As a result of our observations, we suggest that the systematic position of the genus Trimyema be changed from the subclass Vestibulifera to the subclass Gymnostomata. We also consider that this genus must be included in the suborder Trimyemina Jankowski, 1980.

Notes: Specimens of Pelomyxa palustris from five collecting sites had numerous nonmotile flagella. The structures are called flagella because of morphological similarities to flagella and because P. palustris has affinities with amoeboid flagellates. Flagella were photographed on living cells and studied by transmission and scanning electron microscopy. From 64 to 742 flagella per cell were estimated from scanning electron microscopy of ten cells 204 to 1269 μm in length. The nonmotile flagella arise from basal granules which were, in one strain, surrounded by radiating electron-dense microtubules. This strain also had excess axonemal microtubules. Abundant cytoplasmic microtubules were arranged in several different patterns. In about half of the P. palustris cells in which nuclei were studied, microtubules were either apposed to the nuclear membrane in a parallel alignment (with some also radiating) or radiating from the nuclear membrane (with none parallel). Bacteria associated with nuclei were of three characteristic types: Gram-negative rods, Gram-positive rods, and large rods. All nuclei within a given trophozoite had similar perinuclear features. Recent proposals for separation of Pelomyxa to its own phylum (based on its proposed primitive, unique nature) can not be justified. Pelomyxa is a complex, highly specialized organism adapted to live in a specific fresh-water environment. Mastigamoebid amoeboid flagellates of the genera Mastigamoeba, Mastigella, Mastigina, and possibly Dinamoeba are placed with Pelomyxa within the order Pelobiontida Page, 1976, emend., containing two families. Pelomyxidae Schulze, 1877, and Mastigamoebidae Goldschmidt, 1907.

Notes: . Moles from Japan were examined for coccidian oocysts, and 67 of 77 (87%) hosts were infected including 8 of 11 (73%) Euroscaptor mizura, 31 of 36 (86%) Mogera kobeae, 17 of 17 M. tokudae, and 11 of 13 (85%) M. wogura. Of 67 infected hosts, 57 (85%) had multiple infections representing 2–5 coccidian species when examined. All oocysts in the infected fecal samples remained unsporulated and the absence of sporulation may be the result of storing feces from Japanese moles in 2% aqueous H2SO4. Five structurally distinct forms of unsporulated oocysts were found in E. mizura, and five distinct forms of unsporulated oocysts were also seen in Mogera spp. Two of the forms from E. mizura were similar to forms from Mogera spp., and the five forms from Mogera were shared freely between the three Mogera species. This is the first systematic survey of Japanese moles for coccidia.

Notes: . Total cellular DNA from the ciliates Halteria grandinella and Trithigmostoma cucullulus was analyzed by agarose gel electrophoresis. The macronuclear DNA (MAC DNA) of Halteria consisted of very small fragments, which suggests that the MAC DNA organization of oligotrichs resembles that of hypotrichs (gene-sized DNA). The MAC DNA of Trithigmostoma, a cyrtophorid having a heteromeric MAC, also existed as small fragments, but with a significant fraction (20–30%) comprising larger molecules unresolved by the method used. It is suggested that MAC heteromery is related to the differential localization of two kinds of DNA molecules of different sizes.

Notes: . Moles from England were examined for coccidian oocysts and all 64 Talpa europaea were infected; of 64 infected hosts, 56 (88%) had multiple infections representing two to six coccidian species when examined. Oocysts in 31 of the 64 samples remained unsporulated. Three eimerians and one isosporan were studied from the 33 fecal samples that had sporulated oocysts and these are described as new species; Cyclospora talpae Pellérdy & Tanyi, 1968, and Isospora sofiae (Golemansky, 1978) Levine & Ivens, 1979, are redescribed; and Cyclospora sp., similar to C. talpae, is discussed. Sporulated oocysts of C. talpae are ellipsoidal, 14.3 × 9.6 (12–19 × 6–13) μm with sporocysts ovoid, 9.4 × 5.7 (6–13 × 4–8) μm; it was found in 21 of the 33 (63.6%) sporulated samples. Sporulated oocysts of Cyclospora sp. are subspheroidal to ellipsoidal, 12.5 × 8.9 (10–14 × 6–12) μm with sporocysts ovoid, 8.6 × 5.3 (6–10 × 4–6) μm; it was found in 21 of the 33 (63.6%) sporulated samples. Sporulated oocysts of Eimeria avonensis n. sp. are elongate-ellipsoidal, 15.0 × 9.6 (13–20 × 7–12) μm with sporocysts ovoid, 6.6 × 3.6 (5–9 × 3–7) μm; it was found in 15 of the 33 (45.5%) sporulated samples. Sporulated oocysts of Eimeria berea n. sp. are subspheroidal, 12.1 × 10.5 (10–15 × 8–14) μm with sporocysts ovoid, 6.3 × 3.9 (5–10 × 2–5) μm; it was found in 8 of the 33 (24.2%) sporulated samples. Sporulated oocysts of Eimeria globula n. sp. are spheroidal, 20.9 × 19.9 (19–24 × 17–21) μm with sporocysts elongate-ovoid, 11.5 × 6.9 (9–16 × 6–9) μm; it was found in 3 of the 33 (9.1%) sporulated samples. Sporulated oocysts of Isospora sporopointaea n. sp. are subellipsoidal to ellipsoidal, 17.1 × 11.4 (13–21 × 8–14) μm with sporocysts ellipsoidal with both ends pointed, 11.9 × 5.9 (9–16 × 4–8) μm; it was found in 27 of the 33 (81.8%) sporulated samples. Sporulated oocysts of I. sofiae are spheroidal to subspheroidal, 12.2 × 11.0 (9–16 × 8–15) μm with sporocysts ovoid, 9.1 × 5.2 (6–13 × 3–8) μm; it was found in 25 of the 33 (75.8%) sporulated samples. To date, the coccidian parasites of talpids include two cyclosporans, 12 eimerians, and six isosporans, exclusive of the four new species described here.

Notes: . This report deals with a group of ciliated protozoa with short ciliary bands found mainly in the cecum of black rhinoceros, Diceros bicornis (Linnaeus, 1758), and white rhinoceros, Ceratotherium simum (Burchell, 1817) from southern Africa. A new genus, Rhinozeta, based on the sum total of the characteristics of seven new related species is described. The species described are R. rhinozeta n. sp., R. triciliata n. sp., R. caecalis n. sp., R. addoensis n. sp., R. cristata n. sp., R. multiplatus n. sp., and R. unilaminatus n. sp. The specific features of the new genus make it incompatible with any of the known families of the Order Entodiniomorphida containing the ciliates present in the digestive tract of herbivorous mammals. This merits the creation of a new family, the Rhinozetidae.

Notes: . Four isosporan species are described from the small tree finch, Camarhynchus parvulus from Isabela Island on the Galapagos Archipelago. Isospora exigua n. sp. oocysts subspheroidal, one-layered, smooth, yellow-brown color, 20.4 × 20.1 (20-23 × 18-23) μm, with no micropyle, residuum, or polar body. Sporocysts ovoidal, 14 × 9.5 (13-15 × 8-10) μm, with small Stieda and substieda bodies and irregular-shaped residuum. Isospora rotunda n. sp. oocysts subspheroidal, single-layered, smooth, yellow-brown wall with large polar body and no micropyle or residuum, 20.9 × 20.8 (20-24 × 19-23) μm. Sporocysts ovoidal, 15 × 9.7 (13-16 × 9-10) μm with knob-like Stieda bodies, prominent substieda bodies and round residuum. Isospora fragmenta n. sp. oocysts subspheroidal with no micropyle or residuum but with many splinter-like polar granules and a smooth, colorless, single-layered wall, 25.3 × 24.2 (24-27 × 23-25) μm. Sporocysts piriform 15.4 × 11.5 (14-17 × 11-12) μm with knob-like Stieda bodies, prominent substieda bodies, and irregular-shaped residuum. Isospora temeraria n. sp. oocysts ellipsoidal with one polar body, no micropyle or residuum, and wall of a single layer, smooth, yellow-brown color, 25.4 × 21.1 (21-30 × 17-23) μm. Sporocysts piriform, 15 × 10 (14-15 × 9-11) μm with knob-like Stieda bodies, prominent substieda bodies, and a round residuum. One woodpecker finch, Cactospiza pallida, was found to be infected with I. exigua, and a warbler finch, Certhidea olivacea was infected with I. fragmenta.

Notes: The ultrastructural features of cell division in the biflagellate, phagotrophic euglenoid, Entosiphon sulcatum, have been examined. Prophase is marked by the appearance of daughter feeding apparatuses and the emergence of two additional flagella. Pairs of flagella begin to migrate laterally along the surface of the elongating nucleus and remain lateral to the developing spindle poles. As the nucleolus elongates, it becomes dumbbell-shaped and the chromosomes move to the center of the nucleus, forming a loosely organized metaphase plate. Microtubules from opposing spindle poles attach to one of the pair of kinetochores found on each chromosome. The initial chromosome separation occurs during anaphase as the nucleus elongates. The length of the chromosomal microtubules does not decrease until late anaphase/early telophase. As the nucleus elongates, it forms a dumbbell-shaped structure. Most of the remaining microtubules are positioned in the interzone between the forming daughter nuclei. The interzonal spindle becomes somewhat constricted but remains intact until it is broken by the impinging cleavage furrow. Replication of the pellicular strips is not completed until late in cytokinesis.

Notes: The storage carbohydrate granules from Euglena and Pavlova were compared by light and electron microscopy. Freezeetch studies demonstrated that while both types of granules are crystalline, they have different structures. The elemental microfibril of the euglenoid granule measures 4 nm, and the elemental striation of the granule from Pavlova is 22 nm. The granules each have a unique X-ray diffraction pattern. The storage carbohydrate granules from Pavlova are not the same as paramyton, and the term “paramylon” should be reserved for the euglenoid storage carbohydrate.

Notes: A random-walk model of food-searching behavior is considered for the microzooplankton. It is suggested that in still waters a random walk of the conventional sort, modeled by a Wiener process, is less efficient than a Levy walk (a random walk whose excursions follow a Levy distribution) with Levy parameter less than two. For Levy parameter less than one, however, little advantage is gained by further reduction. In turbulent water, on the other hand, dispersion due to a random walk is dominated by the turbulent diffusion of the medium so that the Levy parameter appears to be less important. The effect of chemosensory responses is considered. It is suggested that these are most useful in still water, whereas in turbulent water their value would be less, and a non-specific filtering behavior might be more plausible.

Notes: Serotonin and catecholamines affect the regeneration of cilia in Tetrahymena thermophila in a dose-dependent manner: micromolar concentrations are stimulatory, whereas millimolar concentrations have little or no effect. This conclusion is based on motility measurements in regenerating cells and on ciliary counts in scanning electron micrographs. In addition, the recognition mechanism for each hormone appears to be specific and independent. Our results suggest an evolutionary link with hormonal mechanisms in multicellular eukaryotes.

Notes: Amicronucleate Paramecium tetraurelia fails to develop an oral apparatus but resorbs the pre-existing one in the sexual cycle. Previous cytological studies have revealed the presence of a shallow, oral depression with a few scattered basal bodies after autogamy or conjugation. The present ultrastructural study of the ectoplasm beneath the oral depression revealed only the presence of a disorganized filamentous reticulum and small blocks of cytopharyngeal ribbons. In addition, beneath the oral depression, a large number of discoidal vesicles were found, similar to but larger in diameter than those normally associated with the cytopharynx of vegetative cells. The oral structures found in amicronucleates in autogamy might be remnants of the pre-existing oral apparatus, but the possibility that they were newly developed was not excluded. The morphogenetic interest of these structures was discussed. It is evident that amicronucleates in autogamy do not develop an extensive oral ultrastructural organization.

Notes: The 115,000-molecular-weight antigen of Trichomonas vaginalis was characterized using monoclonal antibodies developed to three different strains of T. vaginalis and one strain of Tritrichomonas foetus. The antigen was found to be present on all strains or isolates of T. vaginalis examined and was demonstrated to be located on the external surface plasma membrane by agglutination assays and complement-mediated lysis assays. Characteristics of the antigen were assessed with a proteolytic enzyme and periodate oxidation. Periodate treatment of whole T. vaginalis abrogated binding for eight antibodies while use of pronase-treated antigen resulted in loss of antibody binding for two different antibodies. Screening of 19 axenized clinical isolates of T. vaginalis and one strain each of T. foetus and Giardia lamblia with type-specific antibodies delineated three major groups of T. vaginalis based on antigenic specificities (epitope distributions) within the 115,000-molecular-weight antigen. In addition, one epitope of the 115,000-molecular-weight antigen was found only on the immunizing strain. Two epitopes were present on all T. vaginalis isolates as well as T. foetus and G. lamblia. One epitope was common to all T. vaginalis except one. A minimum of six different epitopes of the 115,000-molecular-weight antigen were identified. Antigens purified with type-specific or “common” monoclonal antibodies shared the same partial peptide maps demonstrating relatedness.

Notes: Cells of Entamoeba histolytica grown over a period of four days contained NADP+-dependent alcohol dehydrogenase exclusively inside the cells. No activity of this enzyme could be found in the growth medium after harvesting the cells. Under the same conditions, acid phosphatase, β-N-acetylglucosaminidase, esterase, α-glucosidase, and different amylases of the parasite were found both inside the cells and in the medium. The activities present in the cell homogenate and in the medium before and after growth of the amoebas were partially separated by gel filtration on Sephadex G150 and G75, respectively. The comparison of the elution diagrams revealed that NADP+-dependent alcohol dehydrogenase, acid phosphatase, esterase, and amylases occurred as multiple forms inside the cells. These activities, as well as β-N-acetylglucosaminidase and α-glucosidase, were released into the extracellular environment to a different degree. The enzymes originating from the parasite were identified and distinguished from those of the ingredients of the growth medium according to their molecular mass and pH optimum. Furthermore, the amoebic origin of the secreted enzymes was shown on the basis of their inhibition by antibodies prepared against the supernatant fraction of the homogenate.

Notes: A previously reported microsporidium in Penaeus merguiensis de Man, 1888 (Decapoda, Penaeidae), in the Philippines has been identified as a species of Agmasoma Hazard & Oldacre, 1975, and named Agmasoma aquinoae n. sp. (Microsporida, Thelohaniidae).

Notes: The fine structure of trypanosomatids from the plants Euphorbia hyssopifolia, E. characias, E. pinea, and Manihot esculenta, cultivated under axenic conditions, was compared. All parasites had a structural organization characteristic of members of the Trypanosomatidae. The organization of the membranes of the endoplasmic reticulum (ER) varied according to the isolate. In Phytomonas francai (isolated from M. esculenta), the ER cisternae form parallel rows. In Phytomonas sp. from E. characias, a para-crystalline array of the ribosomes attached to the ER membranes was observed. The ER membranes found in Phytomonas sp. from E. pinea seemed to originate from the central portion of the protozoon, branching in all directions. The peroxisome-like organelle (glycosome) found in Phytomonas sp. from E. hyssopifolia and E. characias occasionally showed an organized array. Taken together, the morphological observations make it possible to distinguish the four isolates of Phytomonas.

Notes: Here we describe a method that allows the isolation of intact trypanosomatid symbionts in amounts sufficient for biochemical analysis. The isolated symbionts retain their characteristic morphological features and are reasonably free of subcellular debris. They actively incorporate [3H]leucine and [35S]methionine into proteins. Chloramphenicol and rifampicin at 50 μg/ml almost completely inhibit the incorporation of protein precursors. The inhibition of protein synthesis by the antibiotics provides direct evidence for the existence of a prokaryotic protein-synthesizing system in this unusual intracellular structure. The pattern of protein synthesis of the isolated symbionts is complex. Several symbiont polypeptides are absent or poorly represented in the flagellate.

Notes: Eimeria bovis has two types of first-generation merozoites with distinct ultrastructural characteristics. Type I merozoites were relatively large (X = 13.2 times 1.5 μm) and crescent-shaped, contained numerous micronemes and amylopectin granules, had a posteriorly located nucleus and a conical-shaped posterior tip, and were highly motile and capable of penetrating cultured cells. Type II merozoites were small (X = 5.9 times 0.9 μm) and spindle-shaped, had a centrally-located nucleus, few micronemes, few or no amylopectin granules, a dome-shaped posterior tip and little motility, and appeared to be incapable of penetrating cultured cells. It is possible that these two types of merozoites have considerably different roles in the life cycle of E. bovis.

Notes: To better understand the general distribution of glycoproteins and the distribution of specific glycoprotein-bound sugar residues in Paramecium, a survey of the binding pattern of selected lectins was carried out in P. tetraurelia, P. caudatum, and P. multimicronucleatum. Lectins studied were concanavalin A (Con A), Griffonia simplicifolia agglutinins I and II (GS I and GS II), wheat germ agglutinin (WGA), Ulex europaeus (UEA I), peanut agglutinin (PNA), Ricinis communis toxin (RCA60) and agglutinin (RCA120), soybean agglutinin (SBA), Bauhinia purpurea agglutinin (BPA), Dolichos biflorus agglutinin (DBA), and Maclura pomifera agglutinin (MPA). Those giving the most distinctive patterns were Con A, GS II, WGA, UEA I, and PNA. No significant differences were found between the three species. Concanavalin A, a mannose/glucose-binding lectin, diffusely labeled the cell surface and cytoplasm and, unexpectedly, the nuclear envelopes. Events of nuclear division, and nuclear size and number were thus revealed. Both WGA and GS II, which are N-acetylglucosamine-binding lectins, labeled trichocyst tips, the cell surface, and the oral region, revealing stages of stomatogenesis. The lectin WGA, in addition, labeled the compartments of the phagosome-lysosome system. The lectin PNA, an N-acetyl galactosamine/galactose-binding protein, was very specific for digestive vacuoles. Finally, UEA I, a fucose-binding lectin, brightly labeled trichocysts, both their tips and body outlines. We conclude that a judicious choice of lectins can be used to localize glycoproteins and specific sugar residues as well as to study certain events of nuclear division, cellular morphogenesis, trichocyst discharge, and events in the digestive cycle of Paramecium.

Notes: A simple method for isolation of plasma membrane from Acanthamoeba using self-generating gradients of Percoll is described. To obtain a membrane marker, intact amoebae were radioiodinated and the distribution of the radiolabel was followed through the plasma membrane isolation procedure. The purity of isolated plasma membrane was assessed by enrichment of radiolabel, by electron microscopy, and by enzymatic assays for contaminating membranes. As judged from enrichment of radiolabel, a 37-fold purification of plasma membrane was obtained. We estimate that 80% of the total protein was from plasma membrane and 10% from membrane-associated actin.

Notes: . We have studied linkage disequilibrium in natural populations of Trypanosoma cruzi, the agent of Chagas’ disease, by analyzing (i) a set of 524 stocks from the whole geographical range of the parasite, characterized at four gene loci coding for enzymes; (ii) a subsample of 121 stocks characterized at 12 enzyme loci; and (iii) a subset of 386 stocks from six locations in Bolivia, characterized by four enzyme loci. Our results show that the linkage disequilibrium reaches the maximum possible value, given the observed allelic frequencies, for almost all the locus pairs. This result is most consistent with the hypothesis that genetic recombination is absent or very rare in T. cruzi natural populations. Partition of the linkage disequilibrium variance for the six Bolivian populations shows that both inter- and intrapopulation components are substantial and that the relationships among the components are DIS2 〈 DST2, and D'IS2 〈 D'ST2. These inequalities are interpreted as the result of an interplay between genetic drift, rare or absent mating, and clonal selection in generating linkage disequilibrium in T. cruzi populations.

Notes: . The population of organelles in the periphery of the contractile vacuole of Amoeba proteus has been studied throughout the cycle using proper fixation and dehydration procedures on serial semithin and thin sections. Three distinct types of perivacuolar vesicles which arise successively from one another in the course of the cycle have been described. Size relationships have been determined by stereology.

Notes: . The binding of synthetic peptides modeled from the sequence of the cell attachment site of fibronectin to T. cruzi trypomastigote surface receptors was investigated by fluorescence-activated cell-sorting analysis using fluorescein-labeled peptides. Peptides with the sequence Arg-Gly-Asp-Ser bound to the parasite surface. A low percentage of fresh parasites recently liberated from infected fibroblasts had the capacity to bind the peptide. In contrast, these parasites showed a time-dependent several-fold increase in their ability to bind the Arg-Gly-Asp-Ser-containing peptides during extracellular incubation. From these observations, it appears that the expression of surface receptors on a particular, mature stage of the parasite parallels its ability to adhere to and infect host cells.

Notes: . Geographically diverse strains and clones of Tritrichomonas foetus have been examined with respect to their expression of a major surface antigen of approximately 150,000 relative molecular weight (Mr), designated the 150 Ag. Radioiodination and 13S-methionine labeling of T. foetus followed by immunoprecipitation with monoclonal antibodies (MAbs), separation of polypeptides by SDS-PAGE, and autoradiography or fluorography confirmed the parasite origin of the 150 Ag. The results of flow cytometry analysis employing a panel of MAbs against live T. foetus parasites revealed that from 5 to 84% of individuals in a given population of T. foetus expressed a particular epitope of the 150 Ag. All strains and clones were positive for surface expression of epitopes of this antigen. These results show that the 150 Ag is widely distributed in populations of T. foetus, confirm the surface location of this antigen, and suggest its importance as a target for protective immune responses.

Notes: . The hypotrich ciliate Onychodromus quadricornutus is remarkable in its potential for voluminous size (up to 900 μm in length), its possession of a unique set of four dorsal spines or horns, and its capability to express two kinds of developmental polymorphism induced by intraspecific predation. Cell length frequencies in replicates of a well-fed clone show normal distributions; starvation followed by intraspecific predation, however, induces cells within a clone to transform into two size classes: small lanceolate cells and cannibal giants. Induction experiments indicate that a substance released by cannibal giants stimulates defensive spine growth in clonemates within 24 h. Giants can also induce spine growth in non-clonemates. Furthermore, O. quadricornutus cells exposed to the predacious ciliate Lembadion magnum also develop hypertrophied spines. Selection experiments show that conspecific giants prey on cells with undeveloped spines (〈 20 μm in length) to a much greater extent than on cells with developed spines (〉40 μm in length). Transformation of a population of similarly sized O. quadricornutus cells into two different size classes may function to increase the range of potential prey sizes available to the O. quadricornutus population; hypertrophied spines appear to function as an inducible defense against intermittent predators appearing in the system including conspecific giants. This is the first reported case of a defensive developmental polymorphism induced by intraspecific predation.

Notes: . We studied the cellular regulation of vesicle exocytosis by Entamoeba histolytica utilizing release of endocytosed 125iodine (125I) labeled tyrosine conjugated dextran; 125I-dextran entered the acid pH vesicles of the amebae and was not degraded during these studies. Exocytosis was temperature dependent with 74%, 36%, 4%, and 0% of 125I-dextran released after 120 min at 37°C, 31°C, 25°C, and 4°C, respectively (P 〈 0.01 for each). Exocytosis at 37°C was inhibited by cytochalasin D (10 μg/ml), EDTA (10 mM), or the putative intracellular calcium antagonist TMB-8 (250 μM) (P 〈 0.01 for each at ≥ 60 min). Calcium ionophore A23187 (1 μM) enhanced exocytosis at 5 and 15 min (P 〈 0.01). Elevation of vesicle pH with NH4Cl (10 mM) had no effect on release of 125I-dextran; phorbol myristate acetate (10−6 M) increased exocytosis by 46% at 30 min (P 〈 0.01). Centrifugation of amebae with target Chinese hamster ovary cells resulted in decreased 125I-dextran release into the cell supernatant after 30 and 60 min at 37°C (by 40% and 42%, respectively, P 〈 0.01); release of 125I-dextran returned to control values with addition of 1.0 g% galactose or GalNac but not with mannose or N-acetyl-D-glucosamine. Amebic phagocytosis of serum-exposed latex beads had no effect on release of dextran by amebae (n = 16). Exocytosis of acid pH vesicles by E. histolytica is temperature-, microfilament-, and calcium-dependent, and stimulated by phorbol esters.

Notes: . The purpose of this research was to determine whether mice could be protected from lethal challenge with Naegleria fowleri by prior intranasal exposure to pathogenic and nonpathogenic Naegleria. Mortality ranged from 0 to 100% for mice inoculated intranasally (i.n.) with 5 × 103 amebae of 13 human isolates of N. fowleri. Mice were immunized and challenged i.n. using live amebae of strains of low, medium, and high virulence. The greatest protection against lethal challenge was afforded by three immunizing doses of 103 amebae per dose of the strain of medium virulence. Nonpathogenic N. gruberi also was used to immunize mice i.n. against lethal challenge with N. fowleri. Protection was greater following immunization with N. gruberi than it was after immunization with N. fowleri, suggesting that nonpathogenic N. gruberi may be a better immunogen in protecting mice against lethal naeglerial challenge.

Notes: . Stomatogenesis in Opercularia coarctata has been studied in specimens treated with Fernández-Galiano's silver impregnation method. The new buccal structures originate from the germinal row and from the parental haplokinety.

Notes: Bruce-Chwatt, L. J., ed., with Black, R. H., Canfield, C. J., Clyde, D. F., Peters, W. & Wernsdorfer, W. H. 1986. Chemotherapy of Malaria. Peters, W. & Killick-Kendrick, R., eds. 1987. The Leishmaniases in Biology and Medicine, Vol. I: Biology and Epidemiology Euzéby, Jacques. 1987. Protozoologie Médicate Comparée. Les Protozooses des Animaux et Leurs Relations Avec les Protozooses de l'Homme, Vol. II: Myxozoa—Microspora—Ascetospora. Apicomplexa, 1: Coccidioses (Sensu Lato). McDougald, L. R., Joyner, L. P. & Long, P. L., eds. 1986. Research in Avian Coccidiosis. Wichterman, R. 1986. The Biology of Paramecium, 2nd ed. Levine, N. D. & Ivens, V. 1986. The Coccidian Parasites (Protozoa, Apicomplexa) of Artiodactyla.

Notes: . One of the two methanogenic endosymbionts of the giant sapropelic amoeba Pelomyxa palustris was isolated in pure culture. The cells were slender non-motile rods (3 × 0.4 μm), sometimes occurring in chains of 3–4 cells. Ultrathin sections revealed a Gram-positive cell wall and conically pointed ends with mesosome-like structures in the cytoplasm. The isolate had a generation time of 10 and 12 h during growth on H2/CO2 and formate, respectively. The optimum growth temperature was 40°C and the optimum pH was 7.8. The G+C content of its DNA was found to be 37.7% mole percent. The isolate was identified as Methanobacterium formicicum.

Notes: Two kinds of pigment structures, pigment vacuoles and pigmentocysts, cause the orange-red color of Pseudokeronopsis carnea (Cohn, 1866). The pigment vacuoles are undischargeable and two to five layers of them form a characteristic ectoplasmic zone. The pigmentocysts mainly surround the infraciliature and show a unique channel which is probably used for extrusion. Previous data on the fine structure of subpellicular granules and extrusomes of hypotrich ciliates are summarized. Their obviously diverse organization argues for a great value of these structures in species identification. The basic structural features of the infraciliature and the cytoplasmic organelles of P. carnea are similar to those found in other hypotrichs; however, a special kind of linear microtubular array borders the longer sides of the cirral bases and the margins of the adoral membranelles and those of the membranes in the right buccal area. To the left of the endoral membrane, these microtubular arrays result in a highly ordered structure reminiscent of oral ribs. This peculiar arrangement of microtubules in cirri and paramembranelles has also been found in the related form, Thigmokeronopsis jahodai, probably indicating a homogeneity of the fine structure of urostylid hypotrichs. In P. carnea, the basal bodies of the paroral membrane are proximally connected like a polykinetid. Its cilia are unlinked, whereas those of the endoral membrane are fused by microfibrillar material. The terms diplostichomonad and polystichomonad only refer to quantitative aspects and omit the evident, high diversity of microtubular and microfibrillar associates occurring in the membranes in the right buccal area. These terms need to be redefined on the basis of more material that is better described.

Notes: Netzelia tuberculata secretes a test composed of siliceous particles cemented together by organic plaques forming a single-layered spheroidal shell. The siliceous particles are produced within cytoplasmic vacuoles by three mechanisms: 1) synthesis de novo by deposition of the silica on a matrix; 2) deposition of silica on particles remaining in digestive vacuoles, including starch grains and undigested walls of yeast cells; and 3) secretion of silica as a hollow sphere at the periphery of vacuoles enclosed by the silicasecreting membrane. The silicalemma (silica-secreting membrane) originates as fibril-containing vesicles (GFV) secreted by the Golgi body. Fusion of these vesicles with membranes surrounding digestive vacuoles or with membranes surrounding specialized vacuoles containing a silica-binding matrix apparently converts the vacuole into a silica-depositing organelle. Small spherules of silica occur on the vacuolar side of the membrane surrounding the developing test granules, marking the presence of silicalemma activity. These colloidal spherules become aggregated into larger spherules that condense to form the siliceous surface of the developing test particle. Other Golgi vesicles, designated Golgi plaque vesicles (GPV), produce the organic plaques that are deposited among the siliceous particles at the periphery of the cell during new test construction during cell division. The fine structure of the GFV and GPV and their role in test wall deposition are discussed in relation to other silica-biomineralizing protozoa, including radiolaria.

Notes: We have measured binding of fluorescein-conjugated succinyl-concanavalin A (Fl-s-Con A) to bloodstream and procyclic forms of Trypanosoma brucei gambiense and to bloodstream forms of T. b. rhodesiense by flow cytofluorimetry. Bloodstream forms bound an order of magnitude less lectin than procyclic forms. Trypsin-treating cells enhanced binding of Fl-s-Con A to bloodstream forms 3–16-fold depending on the strain and the length of trypsinization but had little effect on Fl-s-Con A binding by procyclics. The trypsinization protocol used did not remove major common glycoproteins detected on lectin blots of either life cycle form but removed 〉95% of the variant specific glycoprotein and fragments derived from this protein of bloodstream forms. Microscopically detectable Fl-s-Con A binding to bloodstream forms was confined to the flagellar pocket. Trypsinized bloodstream forms and procyclics bound Fl-s-Con A in the flagellar pocket, on the flagellum, and on the cell surface. Lectin remained cell associated but appeared to redistribute towards the flagellum and pocket when cells that had bound lectin on ice were subsequently incubated at physiological temperatures. The Fl-s-Con A binding had specificity characteristic of the interaction between the lectin and oligosaccharides. These results are consistent with the hypothesis that the variant specific surface glycoprotein blocks binding of the lectin to surface glycoproteins of bloodstream forms and suggest that concanavalin A-binding glycoproteins are abundant in the flagellar pocket of both life cycle forms.

Notes: The fine structure of the trophozoite and cyst of Entamoeba histolytica from the stool of a patient was compared using the freeze-fracture method. The intramembranous particles (IMP's) were heterogeneously distributed on the plasma membrane of the trophozoite and their density was 1139 ± 105/μm2 on the P face and 27 ± 9/μm2 on the E face. Particle-rich depressions and linear particle arrays, reported by other investigators on cultured trophozoites, were also observed on the P face while on the E face such special particle arrangement was not recognized. Particle-free, small protrusions were frequently observed on the P face of the trophozoite membrane. The existence of these protrusions is a new finding. In the cyst, the IMP's were also distributed heterogeneously on both the P and E faces of the plasma membrane. The density of the IMP's, however, was much lower than in the trophozoite: 6 ± 2/μm2 on the P face and averaging less than 1/μm2 on the E face. In freeze-fracture images, the plasma membrane of the cyst showed a variety of configurations from smooth to uneven or ridged surfaces. These morphological alterations of the plasma membrane may be attributed to the aging of the cyst. The thick wall of the cyst had a filamentous tri- or tetra-lamellar structure. The cytoplasm of the cyst was similar in structure to that of the trophozoite and the diameter of the nuclear pores was equal in both trophozoites and cysts.

Notes: A new starvation procedure permitted the study of early events in a protozoon's growth cycle. Growing cultures of Tetrahymena that differed from non-growing cultures by one variable were produced by adding histidine to cells deprived of that amino acid in an otherwise complete medium. Alterations of the nucleotide pools were examined in +His and in -His cultures in the period preceding RNA synthesis by cells in +His medium. High performance liquid chromatographic analysis provided a balance sheet for the difference in purine compounds in the two cultures. The change in rNTP levels occurred only when the cells were resuspended in a fresh medium and was not a function of cell density. These observations point to the presence of a factor(s) in the old medium that inhibits the energy charge increase in rNTP and in purine accumulation.

Notes: We have recently shown that the ribosomal RNA genes of the amoebo-flagellate Naegleria gruberi Schardinger, 1899, strain NEG-M are carried exclusively on a 14 kilobasepair plasmid. To explore the distribution of this unique gene arrangement, we have examined another strain of N. gruberi and four other species from the order Schizopyrenida. All have this unusual gene arrangement although the size of the plasmid varies widely. Species groups based on morphological criteria do not agree with those resulting from comparison of plasmid restriction enzyme patterns.

Notes: . Sphaerospores were found among three species of fish examined from waters known to be enzootic for proliferative kidney disease (PKD) of salmonids. They were detected in the renal tubules of both hatchery-reared rainbow trout (Salmo gairdneri) exposed to the infectious stage of PKD and in chubs (Gila bicolor) in the headwaters of a hatchery where PKD is enzootic. Sticklebacks (Gasterosteus aculeatus) collected near net pens where Pacific salmon had experienced a PKD epizootic were also found to harbor sphaerospores in the lumen of the kidney tubules. The latter two host species contained developmental stages of a myxosporidan in the blood and in the lumen of the kidney tubules which are similar to those of PKX, the causative agent of PKD in salmonid fish. The sphaerospores observed in the rainbow trout are the first to be observed in this species. The similarity to previously observed developmental stages, rarity, and presence of these sphaerospores in salmonid fish from a hatchery where PKD is enzootic suggest that they are the most mature stage of the PKX myxosporidan yet observed.

Notes: . High-resolution polyacrylamide gradient gel electrophoresis (PGGE) was used to separate isoenzymes of 12 Naegleria strains: one N. australiensis, two N. lovaniensis, one N. jadini, two N. gruberi isolated from environmental samples, and six N. fowleri strains isolated from patients with primary amoebic meningoencephalitis. Of the eight enzymes studied, seven showed zymograms with interspecific variation that identified all the species tested. Although the six N. fowleri strains were biochemically the most homogeneous, they showed intraspecific isoenzyme variation that allowed them to be grouped into four zymodemes. The PGGE technique, which separates isoenzymes by their molecular shape, is both sensitive and economical. It offers an addition or an attractive alternative to isoelectric focusing which has commonly been used to aid species identification of Naegleria by separating isoenzymes by their isoelectric point.

Notes: . In an attempt to solve the ambiguity in the taxonomy of the Euplotes crassus, minuta, and vannus group, 19 strains were tested for mating interactions, electrophoresed for isozymic variations, and analyzed by multivariate morphometrics of the conventional diagnostic traits. The overall results supported the validity of the three named species. Inter-specific mating occurred only in a few crassus x vannus strain combinations and was usually inviable. Isozymic variations, in particular of amylases, malic enzyme, and malic dehydrogenase, were very restricted within conspecific strains and were great between non-conspecifics. The species ascertainment of the strains was possible on the basis of clustering and principal component analyses of morphological measures.

Notes: . Among the known life cycle stages of Trypanosoma cruzi only the amastigote form bound lactoferrin (LF), a glycoprotein produced by neutrophils. This capacity was readily demonstrable by indirect immunofluorescence in amastigotes derived from mice, a mammalian cell culture, or grown in an axenic medium. No LF binding was detectable on trypomastigotes from blood or mammalian cells, insect-derived metacyclics or epimastigotes, or on epimastigotes grown in Warren's medium. Serum levels of LF were increased in mice acutely infected with T. cruzi, and amastigotes from the spleens of these animals were found to have the glycoprotein on their surface. The amastigote LF receptor may have biological significance in parasite-host interaction since mononuclear phagocytes also express a LF receptor, and treatment of these cells with LF has been shown to increase their capacities to take up and kill T. cruzi amastigotes in vitro. The LF receptor is the first marker for T. cruzi amastigotes for which a naturally occurring ligand has been described.

Notes: . The following species are described from Indonesian birds: Isospora paddae n. sp. with oocysts 41.5–45.5 × 40.3–41.5 (44 ± 1.15 × 41.2 ± 0.38) and sporocysts 22.8–24.5 × 14.7–17 (24 ± 0.55 × 16.2 ± 0.81) from the Java sparrow, Padda oryzivora, and Isospora indonesianensis n. sp. with oocysts 39.3–43.6 × 37–40.8 (41.8 ± 1.3 × 39.6 ± 1.25) and sporocysts 25.6–28.4 × 15.2–18.5 (27.1 ± 1.05 × 16.8 ± 1.22) from the chestnut Munia, Lonchura malacca (L.). The host birds belong to the order Passerorida.

Notes: . The composition of the fauna of rumen ciliates in zebu cattle in Kenya was surveyed and 13 genera containing 51 species with 19 formae were identified. Four new species were recognized, then described as Diplodinium africanum n. sp., Diplodinium nanum n. sp., Eudiplodinium kenyensis n. sp., and Ostracodinium iwawoi n. sp. In addition, Buetschlia triciliata and Ostracodinium stokyi were found for the second and third times and described as Hsiungia triciliata n. comb. and Enoploplastron stokyi n. stat., with two formae, respectively. The species composition was similar to that of Indian zebu but several species were considered to originate from African native ruminants. In the percentage composition of genera, the numbers of Entodinium, which normally predominate in rumens in other areas, were very low.

Notes: . Giardia trophozoites and cysts, isolated from mammalian and avian hosts, were examined by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and by fluorescent light microscopy for the presence of microbial symbionts. Mycoplasma-like organisms were observed on the surfaces of trophozoites isolated from the prairie vole, laboratory rat, and beaver. Intracellular bacteria were observed by TEM in the trophozoites and cysts of G. microti and by fluorescence microscopy in trophozoites and cysts of Giardia spp. isolated from beaver, muskrat, great-blue heron, and the green heron. Trophozoites of G. muris from rat small intestine contained viral-like particles measuring 60 nm in diameter. These observations suggest that biological associations between Giardia spp. and diverse microbes may be more common than formerly appreciated. It also raises the possibility of transmission of these apparent symbionts, via the Giardia cyst, to other mammalian hosts including man.

Notes: . Plasmodium falciparum-infecled erythrocytes were metabolically labeled with tritiated glucosamine. Lipid extracts were analyzed by high-performance thin-layer chromatography to compare labeled molecules of eleven isolates from patients, six cytoadherent in vitro strains, and two knobbed and two knobless strains from Aotus monkeys. Up to nineteen labeled bands were identified. Glycolipid GL1, previously identified in Malayan Camp, was present in all isolates and strains. Other molecules, between CG and GM1 and between GM1 and GD1a, varied in mobility or presence. There was no apparent association between labeled molecules and the presence of knobs or the property of cytoadherence.

Notes: Five ciliate species collected from the Woods Hole area were examined by protargol silver impregnation and scanning electron microscopy. These ciliates have been shown to sequester and use chloroplasts obtained from flagellate prey. One new species, Strombidium chlorophilum, is described. Four other species, Strombidium capitatum (Leegaard, 1915) Kahl, 1932, Strombidium conicum (Lohmann, 1908) Wulff, 1919, Strombidium acutum (Leegaard, 1915) Kahl, 1932, and Laboea strobila Lohmann, 1908, are redescribed. Characters used in describing the Strombidiidae include cell size and shape, anterior and ventral polykinetids, macronuclear shape and size, the kinetid “girdle,” the ventral kinety, the trichites, and the paroral kinety. The rationale for using these characters as taxonomic criteria is discussed.

Notes: A new species of coccidium, Tyzzeria chalcides, is described from the ocellated skink, Chalcides ocellatus, from Egypt. Meronts occur in the epithelial cells of the bile ducts and gamonts within the epithelial cells of the gall bladder. Fully sporulated oocysts are cylindrical (L/W ratio 1.88) without a micropyle, oocyst residuum, or polar granule and contain eight spindle-shaped sporozoites and no sporocysts. Sporulation is completed within the gall bladder lumen. Comparison with other species of the genus found in reptiles indicates that it is a new species.

Notes: Eimeria alpacae, E. punoensis, E. lamae, and E. macusaniensis were identified in fecal samples from 189 llama (Lama glama (L.)) adults and 50 llama crias (animals less than one year of age of any species in the genus Lama) from central and western Oregon. In both adults and crias, E. alpacae was the most common species found. The least common was E. macusaniensis, which was found in only two adults. Overall prevalence and numbers of animals with mixed infections was approximately twice as high in crias as in adults.

Notes: Levels of superoxide dismutase (SOD) activity and its properties in Plasmodium falciparum-infected erythrocytes, isolated parasites, and noninfected erythrocytes were studied. A higher specific activity was found in P. falciparum-infected erythrocytes compared to noninfected erythrocytes, resulting from the lower protein content of infected cells and not enzyme synthesis by the parasite, as the superoxide dismutase activity expressed per number of cells was decreased. Superoxide dismutase from noninfected erythrocytes and isolated P. falciparum parasites showed similar sensitivities to various inhibitors and had identical molecular weights and electrophoretic mobilities. These results support the hypothesis of uptake and use of the erythrocytic SOD enzyme by the parasite as a possible mechanism of defense against oxidative stress.

Notes: Sporozoites were excysted from oocysts of Hammondia heydorni obtained from a naturally-infected dog and inoculated into monolayer cultures of bovine pulmonary artery endothelial cells (CPA), Madin-Darby bovine kidney (MDBK) cells, bovine monocytes (M617), or ovine monocytes (WOMO). Sporozoites penetrated all four cell lines and underwent asexual reproduction by endodyogeny (as determined by electron microscopy) to form cyst-like structures at four to nine days after sporozoite inoculation (DAI). At 4–10 DAI, considerably more zoites were harvested from M617 cultures (80.1 times 106 zoites) than from CPA (17.4 times 106), MDBK. (47.3 times 106), and WOMO (53.5 times 106). Little or no parasite multiplication occurred at 10–16 DAI. Zoites harvested at 7 DAI and transferred to freshly prepared cultures did not penetrate cells nor develop further.

Notes: Paramoeba invadens is a pathogenic marine amoeba responsible for mass mortalities of sea urchins (Strongylocentrotus droebachiensis) along the Atlantic coast of Nova Scotia in the early 1980's. The amoeba has been maintained in vivo in S. droebachiensis for five years in the laboratory without observable loss of virulence. Paramoeba invadens was cultured polyxenically (on mixed marine bacteria) and monoxenically (on a single strain of Pseudomonas nautica) on non-nutrient agar for 58 weeks and 19 weeks respectively. Pathogenicity tests showed some loss of virulence in monoxenic culture after 15 weeks and in polyxenic culture after 58 weeks. Polyxenic culture is recommended for long-term culture of P. invadens although periodic passage of the amoeba through the sea urchin host may be required to maintain virulence for periods exceeding one year.

Notes: The lectin, Concanavalin A (Con A), inhibits cell pairing during mating in Tetrahymena and binds to the surface of pairing cells via receptors concentrated around the conjugation junction. Concanavalin A is also ingested in large amounts into food vacuoles. To dispel the possibility that Con A inhibits pairing via uptake into food vacuoles or through induction of food vacuole formation and to strengthen the idea that pairing is blocked through binding of Con A to cell surface receptors, we have conducted three types of experiments: 1) attempts to inhibit pairing by feeding with nutrients and with tantalum, a non-nutritive reagent; 2) a temporal analysis of the presence of food vacuoles in mating cells fed with tantalum; and 3) analysis of the restoration of pairing following the addition of α-methyl mannoside to cells previously treated with inhibitory concentrations of Con A. The results of these studies support the idea that Con A inhibits pairing by binding to receptors located on the cell surface and not by induction of or uptake into food vacuoles. We also present evidence that cells grown in an enriched proteose peptone medium are able to pair and undergo morphogenesis more readily than cells grown in 2% proteose peptone.

Notes: The ciliate Vestibulongum corlissi n. g., n. sp. was collected from the intestines of surgeonfish, Acanthurus xanthopterus, in the summer of 1986. In has been examined in the light microscope after protargol staining and by scanning and transmission electron microscopy. Its form is distinct from that of other pycnotrichid ciliates at the generic level. Somatic kinetids were examined; these demonstrate that its cytostome is posterior and that the kinetid structures and the presence of a second transverse microtubular ribbon confirm its placement in the class Litostomatea.

Notes: In the sexual process, amicronucleate Paramecium tetraurelia, unlike micronucleates, fail to produce an oral apparatus, but resorb the pre-existing one. Exceptions were found in some amicronucleate cell lines in which about 1% of the cells possessed oral structures, including pieces of oral membranelles, sometimes complete with buccal cavity, after autogamy or conjugation. By following oral development in the sexual process in some detail, the present study supports the view that these oral structures are derived from the pre-existing oral apparatus and not newly developed from the oral primordium. The possible involvement of the micronucleus and the pre-existing oral apparatus in oral resorption is discussed. The possession of a functional oral apparatus after the sexual process may open up a new evolutionary avenue to the amicronucleates.

Notes: . Testate amoebae occur in diverse environments including well aerated streams and anoxic bottom sediments. They consume a wide variety of food including algal prey, bacteria, and detritus. Since little is known about the physiological ecology of many of these widespread organisms, some respiratory and digestive enzyme activities were assessed using Netzelia tuberculata, which is readily cultivated in the laboratory. Activities, expressed as units/μg protein are as follows: acid aryl phosphatase, 19.0 × 10−1; acid protease, 26 × 10−3; cytochrome oxidase, 2.3 × 10−4; and lactate dehydrogenase, 3.6 × 10−4. No amylase was detected in these specimens, which may help to explain why starch grains, apparently consumed from algal prey, are expelled from the cytoplasm and used as wall-construction particles.

Notes: . A sessile, tentacle-bearing protozoon, Heliophrya sp. (Suctoria, Ciliata), reproduces asexually by evaginative budding to form a ciliated swarmer, which begins metamorphosis to the adult form within 30 min of its release from the parent cell. Morphological features of embryogenesis were investigated using transmission and scanning electron microscopy and found to correspond, with certain exceptions, to the few previous reports concerning evaginative budding in suctorians. Following invagination of a portion of the pellicle to form an embryonic cavity within the parent cell, numerous kinetosomes, apparently formed de novo, organize into rows which surround the embryonic cavity and eventually develop cilia that project into the cavity. When the cavity is complete, its walls are extruded through an opening in the parent cell surface. Parent cell cytoplasm streams into the incipient swarmer, thus supplying it with at least the minimum requirement of all cytoplasmic organelles. The ciliated swarmer remains attached to its parent cell for several minutes before it detaches. A complete pellicle is formed in both parent and swarmer prior to detachment. The numerous mitochondria underlying the parent cell pellicle in the vicinity of the attachment area suggest that cross wall formation is an energy-dependent process.

Notes: . Eimeria turcicus n. sp. (Apicomplexa: Eimeriidae) is reported from the gall bladder of the Mediterranean gecko, Hemidactylus t. turcicus (Linnaeus, 1758) from the Houston Zoo, Texas, USA. Oocysts of this coccidian are elongate and cylindrical, 38.2 × 17.9 (35.2-40.8 × 16.8-20.0)μm, with a smooth, bilayered wall ∼ 1.6 μm thick; shape index 2.1 (1.9-2.3). A polar granule is present, but a micropyle and oocyst residuum are absent. Sporocysts are ovoid, 11.0 × 8.8 (10.0-12.0 × 8.0-9.4) μm, with a smooth, thin wall and suture; shape index 1.3 (1.1-1.4). Each sporocyst contains a residuum measuring 6.0 × 5.1 (4.8-8.0 × 4.8-6.4) μm, additional residual granules scattered among the sporozoites, and two sporozoites that are normally arranged head-to-tail within the sporocyst. Each sporozoite contains a single, ovoid, posterior refractile body and a central nucleus.

Notes: . Sporozoites of the coccidium, Caryospora duszynskii, penetrated human fetal lung cell cultures but did not undergo asexual or sexual multiplication during a 29-day observation period. Beginning three days postinoculation (PI), infected host cells lost their normal elongated fibroblast-like shape and became ellipsoidal in appearance and resembled caryocysts. These caryocyst-like infected cells were observed from 3 through 29 days PI. Sporozoites remained viable throughout the study as evidenced by motility of extracellular sporozoites in infected human fetal lung cell cultures. Results of this in vitro study suggest that some species of Caryospora may form caryocysts in secondary hosts without undergoing asexual or sexual multiplication in these hosts.

Notes: . Ophryoscolecid ciliates from the order Entodiniomorphida show a series of morphological types which have been interpreted as an evolutionary lineage. In this study, ultrastructural information from three species—the ancestral Entodinium, intermediate Eudiplodinium maggii, and the advanced Epidinium—has been evaluated in terms of ophryoscolecid evolution. The infraciliature, nuclei, contractile vacuoles, cortex, and cytoplasm are all very similar and sometimes indistinguishable among the three species, suggesting a close relationship. The cytoalimentary system, however, shows considerable interspecific variation. The cytopharynx differs in position and extent of microtubules and microfilaments, varying in appearance from a microtubular to a microfilament-based mechanism while retaining similar component structures. The esophagus, a zone of cytoplasm extending from the cytopharynx and delimited by a microtubular/fibrillar wall, is rudimentary in Entodinium, sac-like in Eudiplodinium, and tube-like in Epidinium, where it also has convoluted walls and a sheath of fibrous material that suggest an expansible-contractile structure. These variations have been related to type of food particle ingested. The capability of the cytoalimentary systems seems to be increased so that the more advanced forms can exploit a food resource, in the form of large plant fragments in the ruminal fluid, not available to the simpler, ancestral forms, which tend to ingest small particles such as bacteria and starch grains. The original evolutionary lineage based on morphological studies using light microscopy is supported by our observations, in these three forms, of ultrastructural variations in the cytopharynx and in their relationship with diet via possible ingestion mechanisms. Additional support for this evolutionary analysis comes from preliminary studies of other ophryoscolecids in which the cytoalimentary organization is consistent with their positions relative to one another in the evolutionary scheme.

Notes: . There are numerous mucocysts in Tetrahymena; however, little is known about their composition, organization, biosynthesis, or function. Mucocysts of Tetrahymena are membrane-bounded vesicles located at the cell cortex. They are torpedo-shaped structures (0.9 μm x 0.3 μm) lined up in longitudinal rows along the surface. It is estimated here that each cell contains about 5000 mucocysts. Mucocyst contents are organized in a crystalline manner, but when that material is released by exocytosis, it swells and forms a gel. Using fluorescence microscopy, we demonstrate that mucocysts contain concanavalin A (Con A)-binding material. First, intracellular fluorescent particles in fixed cells incubated with fluorescein-derivatized Con A (F-Con A) have the same distribution, shape, and orientation as mucocysts in living cells. Also, mucocysts were induced to undergo synchronous exocytosis, and the released material formed a capsule around the cell. The capsule was fluorescent after incubation with F-Con A. In both cases fluorescence was abolished by competition with α methyl mannoside, indicating that Con A is binding specifically to a glycosidic component of the mucocyst. Mucocyst capsules also bind wheat germ agglutinin but not soybean agglutinin, pea lectin, or lentil lectin. Preparations of mucocyst material were analyzed by SDS-PAGE. Silver stain revealed a high molecular weight band that had not previously been detected by Coomassie blue staining. That band also stained with Alcian blue, indicating that it is a mucopolysaccharide. Finally, that same band was shown to be Con A binding. Thus the Con A-binding and Alcian blue-staining properties of mucocysts can be attributed to the same high molecular weight mucopolysaccharide component. This study indicates that it may be possible to purify a specific carbohydrate component of mucocysts which may be helpful in analyzing their function, biogenesis, and structural organization.

Notes: . Membrane dynamics of the contractile vacuole complex of Paramecium were investigated using conventional electron microscopy of cells so that the vacuoles were serial-sectioned longitudinally and transversely. During systole, vacuolar membrane collapses first into flattened cisternae which undergo further modification into a mass of interconnected small membrane tubules. These tubules retain their connections with the radiating microtubular ribbons; consequently they are found only in the poleward hemisphere. Permanent connections between ampullae and the collapsed vacuole membrane could not be verified nor was a sphincter-like mechanism for closing such a junction observed. Membranes of the ampullae and the collecting canals also collapse to varying extents into arrays of tubules that remain bound to microtubular ribbons during diastole. Thus vacuole, ampullae, and collecting canal membranes all assume tubular forms when internal volume is at a minimum. Having failed to observe a microfilamentous encasement of the vacuole, we suggest that an alternative mechanism for the “contractile” function should be sought. One such is based on fluid volume increase and fluid flow within transiently interconnected tubular membrane systems that cycle between a tubular and a planar membrane form as internal volume is periodically increased and reduced. The driving force for this mechanism might best be sought in the molecular structure of the membranes of the contractile vacuole complex.

Notes: . Mature gamonts of Haemogregarina magna lie within a type of parasitophorous vacuole (Pv) apparently unique to the haemogregarines. The cytoplasm of infected erythrocytes was separated from the parasite by two Pv membranes. An additional membrane, coated on both sides with electron-dense material, closely invested the gamonts. The apical complex of the gamonts includes a conoid, two preconoidal rings, and an elaborate polar ring complex. The latter consisted of the polar ring and approximately 78 posteriorly directed, radially arranged, “tine-like” structures which fuse as they merge anteriorly into the polar ring. Freeze fracture replicas demonstrated that the pellicle of gamonts of H. magna was structurally similar to that of other apicomplexans. The closely apposed inner membranes of the pellicle formed plates which were arranged into strips along the long axis of the gamont. Calculations indicated that 13 such strips are found around the circumference of the gamonts with about six subpellicular microtubules associated with the inner surface of each strip. Gamonts of H. magna share many structural similarities with the kinetes, ookinetes, and sporokinetes of other apicomplexans. We propose that the conoid and polar ring complex are fundamental features of all apicomplexan “kinetes.”

Notes: . Trichophrya collini has a polygonal, dorsoventrally flattened body (up to 75 μm diam.), with capitate tentacles arranged in 1–3 rows within peripheral fascicles. There is a central polymorphic macronucleus, an associated micronucleus, and numerous peripheral contractile vacuoles with ventral discharge pores. The cell has a multilayered cortex and the cytoplasm contains suctorian organelles such as crescentic bodies, elongate dense bodies, and haptocysts. The highly contractile tentacles have an axoneme with an outer ring of 24 microtubules separated into six groups and an inner ring of six curved lamellae, each with five microtubules. The lamellae at the distal and proximal ends of the axoneme are arranged in a helix, and the outer ring microtubules are joined in a distal connective sheath. In the apical knob of the tentacle, the haptocysts are borne on a central capsule, Reproduction is by endogenous budding to produce a single oval-shaped swarmer, with equatorial ciliature, which metamorphoses within 3 h. These observations suggest that this organism, previously known as Heliophrya collini Saedeleer & Tellier, is synonymous with Platophrya rotunda Gönnert, Craspedophrya rotunda Rieder, and Heliophrya rotunda Matthes. Its endogenous mode of budding assigns it to the genus Trichophrya. but it is distinct from Trichophrya rotunda Hentschel, and should be reclassified to Trichophrya collini (Saedeleer & Tellier).

Notes: . Tissue homogenates containing amastigotes of either Leishmania donovani, L. tropica, or Trypanosoma cruzi were rapidly frozen with 10% glycerol as cryoprotectant. Viability and pathogenicity were maintained for at least 23 years with the Khartoum strain of L. donovani, 22 years with the Malakal strain of L. donovani, and 7 years for L. tropica and T. cruzi. Similar results over a shorter period of time were obtained with a slow-freezing technique.

Notes: . A mouse monoclonal anti-α-tubulin antibody was used to investigate the disposition of the cytoskeletal microtubules of three tissue culture cell lines–J774 macrophages, BSC-1, and Vero cells–infected with the Brazil strain of Trypanosoma cruzi. Indirect immunofluorescence light microscopy was used to demonstrate the antigenic response in host cells and parasites, simultaneously. In all morphotypes of T. cruzi, the monoclonal antibody reacted with all subpopulations of microtubules, inclusively, the subpellicular, flagellar, cytopharyngeal, and mitotic. The host cell cytoskeletal microtubule framework was revealed and the redistribution and destruction of the microtubular lattice in response to parasite infection over a 120 h period recorded. Our results show that after the initial inoculation of tissue cultures with trypomastigotes, the parasites penetrate the cells and locate in the perinuclear region of the cell where they multiply. The number and distribution of host cell microtubules were altered during the infection. The normal radial distribution of microtubules extending from the center of the cell to the periphery was destroyed. The remaining microtubules were observed at the periphery encircling, but well removed from the proliferating parasites. The complete transformation of the parasites was monitored throughout the infection with the end result being the liberation of parasites and the near complete destruction of the microtubular framework of the host cell. A residual population of dividing spheromastigotes was observed in cells liberating trypomastigotes. Colloidal gold labeling of thin sections as seen in the electron microscope affirmed the specificity of our monoclonal antibody to all subpopulations of microtubules in T. cruzi.

Notes: . The purpose of this work is to examine the reorganization process in amicronucleates with defective mouth of the multimicronuclear ciliate, Pseudourostyla levis. The amicronucleates were derived from fragments obtained by transection of normal micronucleates. The cell size of the amicronucleates was extremely unstable and varied from 57.5 to 276.3 μm long (n = 146), whereas the micronucleates kept rather stable cell lengths with a range from 162.5 to 266.3 μm (mean ± SD = 213.1 ± 19.6 μm, n = 206). The renucleates obtained by transplantation of a micronucleus to an amicronucleate returned to almost normal cell size (mean ± SD = 203.7 ± 16.5 μm long, n = 54). Under the usual culture conditions in the amicronucleate cell line, the number of abnormal cells with defective mouth rapidly increased, up to about 60%, until a stationary phase. Similarly, abnormal cells also appeared in micronucleates although the frequency was always less than 10%. The mean number of membranelles in the normal adoral zone of membranelles (AZM) was 82.6 ± 3.9 (±SD, n = 49) vs. 57.3 ± 7.9 (n = 81) in ciliates with defective mouths. The missing part of the AZM was always the anterior part of the lapel. Cells with defective mouth underwent reorganization (= physiological regeneration) under the usual culture conditions. During reorganization, the lapel part of the old AZM was transformed into a new collar part. The defective mouth was repaired through this developmental process. These results suggest that in P. levis the decrease of food supply often leads to the loss of a specific part of the AZM and that this membranellar loss is suppressed by the existence of micronuclei.

Notes: Eimeria sinaitae n. sp. is described from the gall bladder of Agama sinaita from Wasie, Saudi Arabia. Sporulated oocysts are elongate-ellipsoid 34.4 times 22.0 (29.0–40.0 times 17.4–24.5) μm. Oocyst wall is smooth, greenish yellow, 1.2 (1.0–1.4) μm thick, and two-layered. Micropyle, polar granule, and oocyst residuum are absent. Sporocysts are ellipsoid 11.4 times 7.6 (9.8–15.0 times 6.7–9.0) μm. Sporocyst residuum is present. The sporocysts lack a Stieda body. Sporozoites are crescent-shaped, blunt at one end and tapered at the other. Eimeria species from Agamidae are compared.

Notes: As Plasmodium sporozoites undergo gliding motility in vitro, they leave behind trails of circumsporozoite (CS) protein that correspond to their patterns of movement. This light microscopic observation was made using Plasmodium berghei sporozoites, a monoclonal antibody (MAb H4) directed against the immunodominant repetitive epitope of the CS protein of P. berghei, and an immunogold-silver staining (IGSS) technique. Sporozoites pretreated with agents that inhibit sporozoite motility and invasiveaess did not produce trails. Sporozoites that glided on microscope slides coated with MAb H4 left behind considerably longer CS prolem trails than those on uncoated slides, and the staining of these trails was more intense. The fact that the CS protein is an exoantigen continuously released as trails by motile sporozoites, together with our previous finding that anti-CS protein antibodies inhibit sporozoite motility, strongly suggests that the CS protein plays a role in gliding motility. The sensitive IGSS technique used in this study may be a useful tool in the study of the translocation of surface proteins during gliding of other apicomplexans, other protists, and bacteria.

Notes: A study of calcium metabolism in Tetrahymena during the regeneration of cilia evidenced that the process is inhibited by nifedipine and trifluoperazine. This suggests that calcium ions play an important regulatory role in this process. This was confirmed by studies on calcium uptake and efflux which showed that there was a net increase in calcium uptake prior to the reinitiation of motility. The increase coincided with a period of sensitivity to the calcium antagonist TMB-8 and with an increase in the intracellular level of cGMP. The process was also inhibited by neomycin and stimulated by phorbol esters, which suggests that hydrolysis of phosphatidylinositol phosphates may take place as part of the calcium regulatory network during the regeneration of cilia.