ALBERT

Notizen: Two strains of Trichomonas vaginalis, JH162A, with low pathogenicity, and Balt 44, with high pathogenicity, as well as one highly pathogenic strain, KV-1, of Tritrichomonas foetus were studied by freeze-fracture electron microscopy.The protoplasmic faces (PFs) of the cell membranes of all three strains of both species had similar numbers of intramembranous particles (IMPs); however, the particles in the external faces (EFs) of these membranes were least abundant in Trichomonas vaginalis strain Balt 44 and most numerous in those of strain JH162A of this species. In Tritrichomonas foetus strain KV-1 the number of IMPs in the EF was close to but somewhat lower than that in the mild strain of the human urogenital trichomonad. In both species, the anterior, but not the recurrent, flagella had rosette-like formations, consisting of ∼9 to 12 IMPs on both the PFs and EFs. The numbers and distribution of the rosettes appeared to vary among different flagella and in different areas of individual flagella of a single organism belonging to either species. The freeze-fracture electron micrographs provided a more complete understanding of the fine structure of undulating membranes of Trichomonadinae, as represented by Trichomonas vaginalis, and of Tritrichomonadinae (the Tritrichomonas augusta-type), as exemplified by Tritrichomonas foetus, than was gained from previous transmission and scanning electron microscope studies. Typically three longitudinal rows of IMPs on the PF of the recurrent flagellum of Trichomonas vaginalis were noted in the area of attachment of this flagellum to the undulating membrane. The functional aspects of the various structures and differences between certain organelles revealed in the two trichomonad species by the freeze-fracture method are discussed.

Notizen: The kinetics of differentiation and maturation of phagocytic cells during the acute and chronic stages of experimental Chagas' disease was examined by monitoring changes in expression of peroxidase (PO), nonspecific esterase (NSE), C3b receptors (CR), Fc receptors (FcR), and phagocytic ability of cells in the blood, spleen, and peritoneal cavity. The significant changes recorded in the blood were: marked increases in the percentages of CR- and FcR-positive adherent cells during both the acute and chronic phase; Ia-positive cells increased two-fold in the acute period and remained elevated in the chronic stage. In the spleen, the major alterations recorded during both the acute and chronic stages were: two- to three-fold increases in the percentages of NSE- and PO-positive adherent cells and three- to four-fold increases in the proportions of CR- and FcR-positive cells. In addition, Ia-positive cells increased from 70% to approximately 90% of the adherent cell population. In the peritoneal cavity, a two- to four-fold elevation in the percentages of both PO- and NSE-positive cells was observed. The number of Ia-positive cells increased from 10% before infection to 85–90% during the acute phase and to 96–98% during the chronic period. All of the changes described above occurred in the absence of noticeable increases in phagocytic ability except for an elevation in the percentage of circulating latex-ingesting cells seen during chronicity. These results indicate that infection with Trypanosoma cruzi alters the pathways of differentiation of cells of the mononuclear phagocyte lineage.

Notizen: Development of the swine coccidium, Isospora suis, in embryonated chicken eggs is described. The allantoic cavities of eight-to-ten-day-old white Leghorn embryos were inoculated with either 100,000 or 200,000 sporozoites. Developmental stages morphologically similar to those found in the intestines of piglets were present in the endodermal layer of the chorioallantoic membrane (CAM), beginning three days post inoculation (PI). No stages were found in the mesodermal or ectodermal layers of the CAM and none were observed in heart, lung, liver, or spleen. Type I meronts and merozoites were found on days 3 through 10 PI. Type II meronts and merozoites were found days 4 through 10 PI. Mature microgamonts, macrogamonts, and oocysts were found on days 7 through 10 PI. Oocysts appeared to be retained in the endodermal cells and in ovo sporulation did not occur. Attempts to sporulate CAM-derived oocysts were not successful. Isospora suis was not pathogenic for embryos under the conditions of this study. This study represents the first fully documented report of complete development of a mammalian coccidium in chicken embryos.

Notizen: Plasmodium falciparum-infected human erythrocytes grown in vitro do not release 14CO2, when incubated in the presence of [1-14C]glutamate, despite the presence of glutamate dehydrogenase, implying the absence of α-ketoglutarate dehydrogenase activity and the lack of functional tricarboxylic acid cycle in the human malaria parasite. Cultures incubated with [14C]bicarbonate, however, fix CO2 into acid-stable metabolites; CO2 fixation proceeds linearly for up to two hours after an initial brief lag and may contribute appreciably to the metabolism of the parasite.

Notizen: A geneological study shows that about 4% of the cells in healthy, adequately fed Amoeba proteus cultures are inviable. Two different categories of inviability are distinguished. About 44% of all inviability involves twin sisters formed at a division. Another 39% involves single cells with viable sisters and nieces. The inviable singles usually die more rapidly and show fewer visible abnormalities than the twins. The mothers of inviable twins show an increased interdivision time compared to mothers of inviable singles. Both categories of death are more rapid than starvation. The 17% of the deaths which involve aunt-niece pairs appear to be special cases of twin sister or single cell deaths. There is no evidence for stem line division where a cell forms only one viable daughter for several generations. It is proposed that death is a normal occurrence in amoeba populations. It occurs regardless of culture conditions and may be a measure of accumulated lethal mutations in an asexual polyploid organism.

Notizen: Ciba Foundation Symposium 94: 1983. Malaria and the Red Cell. Pitman, London, Medical Education Division, CIBA Pharmaceutical Company, West Caldwell, NJ 07006. 257 pp. £25.00/$35.00. Jira, J. & V. Kozojed. Toxoplasmose-Toxoplasmosis 1968–1975, Vols. 1 & 2. Gustav Fischer Verlag-Stuttgart. 207 & 395 pp. About DM 180. Phillips, R. S. 1983. Malaria. Edward Arnold, 300 North Charles St., Baltimore, MD 21201. 257 pp.

Notizen: Groups of mice received double infections with the Y and F strains of Trypanosoma cruzi, the first inoculum of either strain being followed by a second inoculum of the other strain on day 5, 15, 30–40, or 60–65. Parasites were re-isolated from blood into culture, either directly or with an intermediate passage in gamma-irradiated mice, at intervals between 7 and 35 days after the second inoculation. Strain identification in the re-isolated material was by electrophoresis of kDNA fragments generated by the EcoRI restriction endonuclease and by electrophoresis for glucosephosphate isomerase isozymes. Both strains were identified in 22% of reislotes originating from the experimental mice and only one of them was present in the remaining re-isolates, strain F being the most frequent. In some instances either Y or F was re-isolated from the same blood source, depending on whether culturing had been preceded or not by passage through a mouse. These results are certainly related to strain differences in the various aspects of host-parasite relationship and, possibly, growth rates in culture. The results demonstrate that: (1) more than one strain of T. cruzi can coexist in the same host; (2) the timing and method of parasite isolation from the vertebrate host act as selective factors, and further passages (inmice or cultures) may completely eliminate one (or more) strain from originally mixed trypanosome populations, and (3) kDNA restriction “fingerprints” and isozyme profiles are simple, sensitive, and reliable techniques for strain identification both in single and mixed preparations.

Notizen: Hepatozoon mocassini (Laveran, 1902) n. comb. from Agkistrodon piscivorus leucostoma (water moccasin) is redescribed by light microscopic study of all developmental stages and reclassified since mature oocysts contained sporocysts. Formerly this species was assigned to the genus Haemogregarina on the basis of a description of the gamonts. A neotype is designated because the original specimens cannot be located. Mature oocysts, containing sporocysts, developed in the hemocoel of the experimental host Aedes aegypti. These oocysts proved infective for A. piscivorus leucostoma when administered orally.

Notizen: Unikaryon matteii n. sp. (Microsporida, Unikaryonidae) parasite le tube digestif, les tubes de Malpighi, les muscles et le tissu adipeux de Nisotra sp. (Coleoptera, Chrysomelidae). Elle se développe en contact direct avec le cytoplasme de la cellule hôte et ne présente jamais de diplocaryon.Les mérontes sont limités par une simple membrane plasmique. Leur cytoplasme présente quelques saccules de reticulum endoplasmique et des vésicules golgiennes. Les mérontes uninucléés sont globuleux (2 μm de diamèGtre). Les mérontes binucléés sont allongés (5 × 1.5 μm) et se divisent par simple étranglement médian pour donner deux nouveaux mérontes uninucléés, qui pourront évoluer en sporontes.La sporogonie est disporoblastique. Les sporontes et les sporoblastes sont limités par une paroi d'environ 15 nm d'épaisseur, et leur cytoplasme présente un reticulum endoplasmique développé. Les sporontes uninucléés (2 μm de diamétre) deviennent binucéés (5 × 2 μm), puis subissent une division binaire pour donner deux sporoblastes uninucléés. Les sporoblastes, d'abord de forme irrégulièGre deviennent ovoïdes (2.5 × 2 μm) puis évoluent en spores.Les spores sont ovales et uninucléées (3.72 ± 0.39 μm × 1.96 ± 0.15 μm). Elles possèGdent un filament polaire qui décrit 5 à 12 tours de spires. Leur polaroplaste est uniquement lamellaire, mais subdivisé en deux parties: I'une, antérieure, constituée de saccules aplatis, I'autre, postérieure, constituée de saccules dilatés.La description d'une deuxièGme espèGce d'Unikaryon chez les coléoptères confirme le développement de ces parasites chez les insectes, et pose le problèGme de la validité de certaines Nosema d'insectes dont les spores sont uninucléées.〈section xml:id="abs1-2"〉〈title type="main"〉ABSTRACT Unikaryon matteii n. sp. (Microsporida, Unikaryonidae) is a parasite of gut, Malpighian tubules, muscles, and fat body of Nisotra sp. (Coleoptera, Chrysomelidae). It develops diffusely in the host cell cytoplasm and is unikaryotic throughout merogony and sporogony.The meronts are surrounded by a simple plasma membrane. Their cytoplasm contains little endoplasmic reticulum and some Golgi vesicles. Uninucleate meronts are globular (2 μm in diameter). Binucleate meronts are elongate (5 × 1.5 μm); by binary fission they give rise to two uninucleate meronts, which may develop into sporonts.Sporogony is disporoblastic. Sporonts and sporoblasts are bounded by an electron-dense wall about 15 nm thick, and their cytoplasm contains some flattened cisternae of endoplasmic reticulum. The uninucleate sporonts (2 μm in diameter) become binucleate (5 × 1.5 μm) and undergo binary fission to produce two uninucleate sporoblasts. The sporoblasts, at first irregular in outline, become ovoid (2.5 × 2 μm) and give rise to spores.The spores are uninucleate and oval (3.72 ± 0.39 μm × 1.96 ± 0.15 μm). They have a polar filament with 5 to 12 coils and a Iamellate polaroplast divided into two parts: an anterior part composed of flattened sacs and a posterior part made up of swollen sacs.The description of a second species of Unikaryon in a coleopteran confirms the development of these parasites in insects. The validity of some Nosema of insects which have uninucleate spores is discussed.

Notizen: The combination of KCl + acriflavine + Ca2+-poor condition, known as conjugation-inducing-chemicals, was found to be autogamy-inducing-chemicals as well. Suspension of a single cell of Paramecium multimicronucleatum, syngen 2 in this medium for three hours or more resulted in autogamy that was evidenced by cytological similarity to conjugation.

Notizen: Giardia sp. cysts were found at levels of 4,000–450,000/378,500 liters (100,000 gallons) in sewage effluents from three of seven sewage treatment plants in Sangamon County, Illinois, in June, July, and August 1981. Effluent from the positive plants is discharged into Lake Springfield (the present source of the city of Springfield's water supply) or the Sangamon River.

Notizen: Light microscopy studies of Culicosporella lunata (Hazard & Savage), a parasite of the mosquito Culex pilosus (Dyar & Knab), revealed two sporogonial sequences. One sequence begins with diplokaryotic meronts that undergo repeated nuclear divisions to produce sporogonial plasmodia with nuclei in diplokaryotic arrangement. These plasmodia form rosette-like clusters of sporoblasts during incomplete cytokinesis and, eventually, binucleate spores. These spores initiate infections in healthy larvae when they ingest spores. The second sequence begins with diplokaryotic meronts that undergo karyogamy and meiosis to form Thelohania-like sporonts and haploid spores. Anomalies are often observed in these sporonts which result in aberrant spores, usually fewer than eight, in an accessory (pansporoblastic) membrane. Normal haploid spores are morphologically similar to those of species of Amblyospora. The genus and the type species are redefined based on new information presented here and it and the type species are placed in the family Amblyosporidae.

Notizen: First and second generation meronts of Eimeria vermiformis developed in epithelial cells of the crypts of Lieberkühn. They were usually between the host cell nucleus and the basement membrane. Sporozoite organelles dedifferentiated with the first generation meront's development except for the refractile body and the apical complex, which persisted. After several nuclear divisions, the apical complex dedifferentiated further until only micronemes remained attached by a duct system to the plasmalemma. The form of the apical complex was highly variable. Sometimes the duct system was absent and the micronemes were attached directly to the plasmalemma or a dense material on it. Crescent body-like material was often present in the parasitophorous vacuole next to the microneme structure. The microneme structure was not present in second generation meronts but evaginations of the plasmalemma, cytoplasmic outpocketings, and cytoplasmic vesicles were associated with the round granular bodies in the parasitophorous vacuoles. During first generation merogenesis, invaginations from the parasitophorous vacuole formed channels into the meront along which merozoites budded. Micropores were often at the ends of these invaginations. These and other micropores of the meront had a dense U-shaped band for a collar while those of the merozoites had a collar with a double band of dense material that connected to the inner membrane. First generation merozoites budded randomly from the meront, resulting in a residual body that was usually in the middle of the parasitophorous vacuole. Second generation merozoites budded in one direction, resulting in a peripheral residual body and merozoites that were parallel in an oblong parasitophorous vacuole.

Notizen: Ultrastructural observations on the sporocarp of the protostelid Cavostelium apophysatum are presented, including information about the mechanism of sporocarp development. The onset of sporogenesis is marked by cessation of trophic activity and the secretion of a protective sheath. The protoplast gradually molds itself into two distinct zones approximating the shape of the final sporocarp–a hyaloplasmic pre-stalk zone and a globose incipient spore zone. The protoplast in the stalk zone deposits a fibrillar and amorphous stalk acropetally as the stalk protoplast moves into the incipient spore region. The last portion of the stalk to be deposited is the apophysis, a hollow cup-like structure at the stalk apex. Spore wall deposition begins as the stalk nears completion. The wall consists of a single electron-dense layer ornamented with hollow cones and solid projections. The mechanism of sporocarp development in C. apophysatum is compared to the developmental patterns of the protostelids Planoprotostelium aurantium and Schizoplasmodiopsis amoeboidea.

Notizen: Cytidine deaminase (cytidine aminohydrolase, 3.5.4.5) is present in Crithidia fasciculata (a mosquito parasite) and in Trypanosoma cruzi (a human pathogen). The enzyme from C. fasciculata deaminated both cytidine and deoxycytidine, the affinity for the former being much lower than the latter. Affinities for both substrates are equal for the T. cruzi enzyme. The production of the enzyme in C. fasciculata was significantly stimulated by the addition of a number of pyrimidine nucleosides (cytidine, uridine, 5-bromouridine, thymidine, orotidine) to the culture media. Only cytidine stimulated enzyme production in T. cruzi. The enzyme from both organisms was unstable in air, even in the frozen state. Stabilization was achieved under anaerobic conditions.

Notizen: The holdfast apparatus fills the posterior half of the larva; it is comprised of cytoplasmic granules called heterosomes and of about twenty collecting canals which converge at a septate chamber, the rosette. The latter opens to the exterior by a secretory appendage called the podite. My hypothesis is that, when the larva attaches to a substrate, the heterosomal contents empty into the collecting canals and are mixed in the rosette. With the aid of the podite, this secretion is applied to the gill substrate where it forms the so-called style of the future adult. The holdfast apparatus of the adult Spirochona comprises two regions of different nature: the pseudostyle, which is the posterior part of the cell, and the style which is an extracellular secretion. The style looks like a truncated cone and adheres firmly to the substrate. The upper face of the style shows 16–18 stylonemes which are inserted in the crypts of the pseudostylar rosette. The latter corresponds to the larval rosette, and the crypts communicate with a chamber and numerous suprastylar acini, which represent the remnants of the larval collecting canals. Except for a few details, the holdfast apparatus appears to be similar among all the chonotrichs studied to date. This apparatus differs from that of the Suctoria and of the Peritricha. It has some analogies with the “mouth-rosette” complex of the Apostomatida. Finally, the presence of a podite in a chonotrich larva is new evidence supporting a closer systematic relationship between the Chonotrichida and the Dysteriidae.〈section xml:id="abs1-2"〉〈title type="main"〉RESUMEL'appareil de fixation occupe la moitié postérieure de la larve; il est composé de granules cytoplasmiques, les hétérosomes, et d'une vingtaine de canaux collecteurs convergeant vers une chambre septée appelée rosette. Celle-la communique avec l'extérieur par un appendice sécréteur, le podite. II est supposé que, lors de la phase d'attachement, le matériel contenu dans les hétérosomes se vide dans les canaux collecteurs et se mélange dans la rosette, puis, grâce au podite, est appliqué sur la branchie où il forme le pied ou style du futur adulte. L'appareil de fixation de l'adulte comprend donc deux parties de nature différentes: le pseudostyle, c'est-à-dire la région postérieure du corps cellulaire, et le style, une sécrétion extracellulaire. Celui-ci forme une masse tronconique intimement fixée au substrat. Sur sa face supérieure, le style porte 16–18 stylonèmes enserrés dans les cryptes de la rosette pseudostylaire. Celle-ci correspond à la rosette larvaire, et les cryptes communiquent avec une chambre et des acini suprastylaires, eux-mêmes vestiges des canaux collecteurs larvaires. A quelques détails près, il semble bien que l'appareil de fixation des Chonotriches actuellement étudiés soit construit sur le même type. Cet appareil de fixation est différent de celui des Suctoria et des Peritricha; il présente peut-être quelques similitudes avec le complexe “bouche-rosette” des Apostomatida. Enfin, la présence d'un podite chez une larve de Chonotriche est un argument nouveau en faveur du rapprochement Chonotrichida–Dysteriidae.

Notizen: During excystment of an amoeba, Cochliopodium sp., scale formation was examined with light and electron microscopy. This amoeba was covered with scales. When the amoeba encysted, the scales remained on the external surface of the cyst wall. Soon after the induction of excystment the Golgi complex began to develop. Many vesicles were extruded from it and changed into vacuoles. Scales were observed first in the vacuole adjacent to the Golgi complex and later in inside the cyst wall. When the amoeba excysted it had been coated by the newly formed scales. It is suggested that the scale formation is dependent on the activity of the Golgi complex.

Notizen: The infection of bovine embryo skin and muscle cells by trypomastigotes of four Trypanosoma cruzi clones (CA-I/71, /72, Miranda/76, /80) was quantified. Stable and reproducible intra-isolate differences were observed; an almost 70-fold difference in infectivity occurred between clones. The CA-I/71 clone was not susceptible to N-acetyl-D-glucosamine at a concentration that inhibits the infection of vertebrate cells by Ernestina and Y-strain parasites. Eight other monosaccharides that are common constitutents of vertebrate cell surface glycoproteins also failed to inhibit the infection of vertebrate cells by the CA-I/71 clone.

Notizen: Scanning electron microscopy confirmed our previous finding that toxoplasmas actively invade mouse peritoneal cells that are inhibited from phagocytosis. The parasites entered cells with the conoid end first and sometimes showed a counter-clockwise torsion of the body during invasion. Counter-clockwise torsion was also noted in free toxoplasmas. Host-cell responses to active invasion varied with experimental conditions and with the type of host cell. Under adverse culture conditions for phagocytosis, normal macrophages formed rudimentary filopodia or lamellipodia around the tips of in vading toxoplasmas; macrophages subjected to hyperthermia before similar incubation with toxoplasmas showed little or no response to invasion. Normal and heat-treated lymphocytes showed little surface reaction to invasion, but occa ionally a flocculent collar was seen around the tip of an invading toxoplasma. Scanning electron microscopy provides clues to possil'e mechanisms of toxoplasma locomotion and host-cell invasion.

Notizen: The potential utility of protein arrays visualized by SDS-PAGE in taxonomic studies of protozoa has been investigated within the genus Tetrahymena. Matching coefficients have been obtained from one-dimensional separations of cytoskeletal proteins in a study involving 40 strains of Tetrahymena. In separate studies, the method was estimated to be accurate to within 10%, and the limit of intraspecific variation within the genus was estimated at ≅ 30%. Accordingly, it is suggested that strains showing matching coefficients 0.6 in these preparations probably represent different species. Further tests using strains identified to species by breeding criteria have shown that the 0.6 rule is asymmetric, i.e. although matching coefficients lower than this indicate separate species, values higher than this do not prove identity. Protein comparisons included in the present study indicate that strain Tur, previously identified as a strain of T. vorax, is distinct from all other macrostome-forming species. It is here designated Tetrahymena leucophrys n. sp.

Notizen: Trypanosoma hydrae from the broad-banded watersnake, Nerodia fasciata confluens, underwent development in the freshwater leech, Placobdella parasitica. Epimastigotes and transitional stages were present only in the crop and gastric caecum. Only one metacyclic form was observed. The potential of leeches as vectors is discussed.Two broad-banded watersnakes were infected by inoculation with culture forms of T. hydrae maintained on NNN medium. Parasitemias varied from 105/ml to 106/ml with dividing forms seen only rarely. A broad and a slender form of T. hydrae are described from the peripheral blood of a watersnake 7 months after an experimental infection.

Notizen: Goodwin, B. C., Holder, N. & Wylie, C. C., eds. 1983. Development and Evolution

Notizen: Variant surface glycoproteins (VSG) of Trypanosoma brucei are released in a water soluble form on impairment of membrane integrity. We have previously shown that this release is the result of an enzyme-mediated event which converts the hydrophobic membrane form VSG into the hydrophilic water-soluble form. We now present further details of the methods by which membrane form VSG (mfVSG) may be isolated, uncontaminated by water-soluble VSG (sVSG). The sensitivity to different metal ions of the enzyme that mediated the conversion event is discussed, and some biochemical characteristics of different mfVSG preparations are presented.

Notizen: Burenella dimorpha, a microsporidian parasite of the tropical fire ant, Solenopsis geminata, produces two morphologically distinct types of spores. The binucleate free spores (spores not bound by a pansporoblast membrane) develop normally at temperatures at least as low as 20°C and as high as 32°C. The uninucleate octospores (spores bound in octets by a pansporoblast membrane), however, develop in a restricted range of temperature. Octospores constituted 35.9%± 2.6 of the spores in 25 pupae held at 28°C. Raising the temperature to 30°C reduced octospores to 〈 1% of the total spore population. Lowering the temperature to 25° or 22°C reduced the octospore population to 8.5%± 6.5 or 0.4 ± 0.5, respectively. Inhibition of octospore development was complete at 20°C. In contrast, the octospores of Vairimorpha necatrix and Vairimorpha plodiae are reported to be abundant at 16°C and 21°C, respectively. The critical event blocked in octospore development may be meiosis, as evidenced by an abundance of binucleate sporonts in the octospore sequence of development, and absence of more advanced sporogonic stages in hosts held at inhibitory temperatures. Free spore size is not affected by temperature although yield may be slightly reduced at elevated temperature.

Notizen: Fine-structural alterations in Trypanosoma rhodesiense trypomastigotes exposed to WR 163577, a prophylactic agent against animal African trypanosomiasis, were determined from cells grown in vitro. Exposure of trypomastigotes to a low concentration of drug resulted only in condensation of kinetoplast DNA fibrils. Exposure to higher drug concentrations caused clumping of nuclear chromatin and of cytoplasmic contents. Although alteration of kinetoplast DNA is the first detectable drug-induced change, the function of the kinetoplast in mammalian forms of African trypanosomes is unclear, and the secondary changes in the nucleus and cytoplasm may constitute the functionally significant alterations caused by WR 163577.

Notizen: Sporozoites of Leucocytozoon caulleryi were inoculated into specific-pathogen-free (SPF) chickens intravenously. Fourteen days after inoculation, the infected blood, parasitized with second generation merozoites, was collected from the chickens. The blood was then suspended in SPF chicken serum or RPMI-1640 culture medium supplemented with 20% SPF chicken serum in petri dishes, which were cultured at 37°C or 41°C in a humidified atmosphere of 5% CO2. Second generation merozoites in parasitized, immature erythrocytes developed continuously through several substages and finally became micro- and macro-gametocytes after 6 days of incubation.

Notizen: . A new species of malaria parasite, Plasmodium (Sauramoeba) heischi, is described from African skinks (Mabuya striata). Eleven individuals of 90 specimens collected in Nairobi were found to be infected. The new parasite is a large species, characterized by spindle-shaped gametocytes, the female often with a subterminal nucleus. The schizonts produce up to 65 nuclei and cause great hypertrophy and distortion of the host cell. Although similar to P. (Sauramoeba) giganteum in dimensions and merozoite numbers, P. heischi is easily distinguished by gametocyte and schizont shapes.

Notizen: . Two persisting stages in the life cycle of a hemogregarine Karyolysus sp. are described from the liver and blood cells of its intermediate host, the lizard Lacerta raddei nairensis. The tissue cell merozoites lie in a parasitophorous vacuole. Despite the protective role of the vacuolar membrane, the intracellular parasites are progressively destroyed and eliminated during the autumn and winter. Some of the merozoites that normally survive within the host cell even in cold seasons appear to be surrounded by another type of parasitophorous vacuole which is connected to the intercellular space by narrow channels. The intraerythrocytic gamonts that persist in the circulating blood are encapsulated and undergo progressive, obvious structural changes. The two persisting stages are compared with hypnozoites of other Sporozoa.

Notizen: . The blastogenic effects of specific parasite antigen and of mitogens on the lymphocytes of chickens infected with Eimeria tenella were examined. Lymphocytes from infected chickens were stimulated to divide when cultured with parasite antigen, but their responses to the T-cell mitogen, phytohemagglutinin (PHA), were depressed throughout the period of infection. Responses to the B-cell mitogen, lipopolysaccharide (LPS), were depressed during the first week of infection but enhanced in the second week. The inclusion of plasma samples from infected chickens in the culture medium depressed the responses of normal spleen lymphocytes to PHA, suggesting that soluble suppressor factors are generated during infection.

Notizen: . Pathological changes and immunity induced by Eimeria vermiformis (Ernst, Chobotar & Hammond, 1971) were studied in outbred Swiss mice inoculated with 5000, 10,000, 20,000, or 40,000 oocysts. Cross immunity to E. ferrisi was also studied. In the case of E. vermiformis, mortality was dose dependent; most deaths were observed in the intermediate-dose groups. Most deaths also correlated with peak oocyst output. Histopathologic changes consisted of an early neutrophil and mononuclear cell infiltration in the small intestine. Later, villus atrophy and crypt hyperplasia caused a decrease in the villus-crypt ratio. During the acute phase (8-10 days after inoculation), villus tips were eroded and parasites with necrotic debris filled the cryptal and intestinal lumina. Vacuolar changes were observed in epithelial cells of the small intestine. Neither parasites nor significant pathological changes were observed in extra-intestinal organs. Mice were totally immune to reinfection with E. vermiformis 30 and 105 days after inoculation. Cross immunity was not observed between E. vermiformis and E. ferrisi.

Notizen: . Plankton and fishes are abundant in Antarctic waters. Benthic invertebrates and fishes of the continental shelf are well-known, but the abyssal benthos below the highly productive open ocean is largely unsampled. The fishes are adapted (with antifreeze properties) to temperatures that are often or always below the freezing points of their body fluids. All the major groups of helminth parasites are found in or on these fishes. The few records of protozoa include Cryptobia, haemogregarines, a monoflagellate, the myxosporan Neoparvicapsula, and (in this paper) Ceratomyxa. Myxidium, Zschokkella, and a coccidian. Most of the protozoa were obtained from nototheniid fishes. No protozoa and few, if any, other parasites were recovered from 173 midwater fishes collected from outside of the continental shelf. Differences in infections in different localities and depths are due to many ecologic factors needing much more study of their relations to parasitism. These factors include temperatures, salinities, densities of fish populations, food and feeding habits, migrations of adult and immature fishes, availability of potential intermediate hosts, and marine “snow.”

Notizen: . A new species of Eimeria from the fat-tailed gecko Hemidactylus brookei in Gambia, West Africa, was described and named E. helenae in honor of Mrs. Helen Levine. The oocysts averaged 22.2 μm and each contained four sporocysts (8.0 × 6.9 μm) with two sporozoites per sporocyst. No schizogony or gametogony was discovered in the intestine, suggesting that these stages may occur in the liver or bile cannuli. The oocysts of an adeleid parasite of the insect prey of the centipede Scolopendrium morsitans were described. Plasmodium agamae, an eimeriid hemogregarine, Pirhaemocyton, and a Shellackia-type parasite were found in the blood of agamid lizards. The fruit bat Epomorphorus gambianus was commonly and heavily infected with Hepatocystis epomorphori.

Notizen: . Sarcocystis-like oocysts-sporocysts were found in four species of owls (Asio otus, Bubo bubo, Strix aluco, and Tyto alba) and in five species of predatory birds (Accipiter gentilis, Accipiter nisus, Buteo buteo. Circus aeruginosus, Falco tinnunculus). In addition, the muscles of 15 of 41 (36.5%) pheasants (Phasianus colchicus) and one of two jays (Garrulus glandarius) were found to harbor three types of Sarcocystis. Three of 15 (20%) infected pheasants had type I cystozoites (6-8 × 2 fim) in muscle homogenates, but sarcocysts were not seen whereas the other 12 infected pheasants had type II cystozoites (16 × 2-3 pm) and sarcocysts (90 × 600 μm) in their muscles. The one infected jay had type III cystozoites (8-10.5 × 2.5-3 μm) and sarcocysts (35-40 × 〉770 μm) in its muscles.

Notizen: Ultrastructural investigations of P. falciparum cultivated in vitro in human erythrocytes revealed new features of the feeding mechanism of the parasite. Mature trophozoites and schizonts take up a portion of the host cytosol by endocytosis which is restricted to cytostomes and which involves the invagination of both parasitophorous and parasite membranes. The resulting endocytic vesicles, surrounded by two concentric membranes, migrate towards the central food vacuole membrane. The external membrane of the endocytic vesicles apposes that of the food vacuole, leading to the internalization of vesicles bounded by a single membrane into the vacuolar space where they are rapidly degraded. We conclude from this sequence of events that endocytic vesicles fuse with the food vacuole. Treatment of infected cells with therapeutic concentrations of chloroquine inhibited the last step of the feeding process, i.e. vacuolar degradation. This was manifested by the accumulation within the vacuolar space of intact vesicles bounded by single membranes. The implications of these findings for the antimalarial activity of chloroquine are discussed.

Notizen: The large cytopharyngeal pouch of the macrostomal form of Tetrahymena vorax, following the addition of calcium, can form a sealed, empty vacuole. The open cytostomal region of this cell, which averages about 16 μ in diameter, is closed by an upward (ventral) movement of the right and posterior ribbed walls, both of which project into the cytostomal cavity. At the same time, the anterior and left walls of the cytostome-cytopharyngeal complex move to the right, forming a diagonally (right to left) placed furrow in the floor of the buccal cavity as these walls meet. As a result of the movement, the edges of the single membrane-bounded cytopharyngeal pouch are brought together and fuse, producing the closed vacuole. Elements of the cytoskeleton appear to participate in the closure process. Three major groups of ribbed wall microtubules support the open cytostome. The anterior ribbed wall microtubules pass laterally along the anterior (dorsal) portion of the cytopharyngeal pouch to the left where they end in the specialized cytoplasm. Middle oral rib microtubules terminate at the right and posterior margin of the cytopharynx while microtubules from the most posterior region of the ribbed wall pass to the left terminating in the specialized cytoplasm. The fine filamentous reticulum, a striated reticulum that borders the right, posterior, and anterior margins of the cytostome-cytopharyngeal complex, is in an ideal position to participate in these movements. It is anchored anteriorly high up in the buccal cavity to the cross-connective between the third membranelle and the undulating membrane complex. It courses beneath the right and posterior ribbed walls and runs laterally along the anterior margin of the cytopharynx to the left side. Contraction or pulling of this reticulum would act to bring the microtubule-reinforced walls of the cytopharynx together permitting fusion of the cytopharyngeal pouch membranes to form a sealed vacuole.

Notizen: The ultrastructure of the sexual stages of Plasmodium gallinaceum during gametogenesis, fertilization, and early zygote transformation is described. New observations are made regarding the parasitophorous vacuole (PV) of gametocytes and the process of emergence in male and female gametocytes. Whereas female gametocytes readily disrupted both the PV membrane and host cell plasmalemma during emergence, male gametocytes frequently failed to break down the plasmalemma of the host cell. New observations and hypotheses are presented on the behavior of the male gamete nucleus. Following fertilization, the male nucleus appears to travel through a channel of endoplasmic reticulum in the female gamete before fusing with the female nucleus at a region in which the nuclear envelope is thrown into extensive convoluted folds. Polarization of the zygote nucleus, in association with the appearance of a perinuclear spindle of cytoplasmic microtubules, preceded all other changes in the developing zygote. After nuclear polarization becomes apparent, electron-dense material is deposited beneath the zygote pellicle, and a canopy is formed which eventually extends over the entire apical end of the developing ookinete. As the apical end begins to extend outward, polar rings, micronemes, and subpellicular microtubules become visible in this portion and a “virus-like” inclusion known as a crystalloid is formed in the posterior portion of the zygote. When female gametes are prevented from being fertilized, the cytoplasm at 24 h after gametogenesis is devoid of most of those organelles found in the developing zygote or the mature ookinete. The cell is surrounded only by a single membrane. Although at various points beneath the membrane there are deposits of electron-dense material reminiscent of those deposited in the zygote, no further development of ookinete structures takes place in the unfertilized female gamete.

Notizen: The somatic and oral cortical ultrastructure of the plagiopylid ciliates Lechriopyla mystax Lynch, 1930 and Plagiopyla minuta Powers, 1933 are described. The somatic kinetids are monokinetids with an anteriorly directed kinetodesmal fibril originating near triplets 5, 6, 7, a divergent postciliary ribbon originating at triplet 9, and an unusual transverse ribbon originating in dense material adjacent to triplets 1, 2, 3. The transverse ribbon extends beneath the right surface of the cortical ridge adjacent to the kinety from which it originated. The oral kinetids are also monokinetids from whose base rootlet fibrils extend inwards beneath the oral kineties and converge on the furcula. The striated band on these ciliates is composed of a series of short ridges orthogonal to the longitudinal axis of the band. The sides of the striated band groove are apparently supported by macrotubules. The cortical ultrastructure of the plagiopylids is discussed with reference both to the optical microscopy of the organisms and to the ultrastructure of other ciliate taxa. The plagiopylids are not clearly related to any other higher taxon and are placed incertae sedis in the Subphylum Cyrtophora Small, 1976.

Notizen: The colonization, distribution, population density, and species diversity of amoebae on leaves of Oak Leaf lettuce, Lactuca sativa var. crispa, and Boston lettuce, L. sativa var. capitata, were investigated. The role of soil in the colonization of Oak Leaf lettuce was determined by comparing numbers of amoebae present on basal leaves (those that pass through soil) with numbers on wrapped leaves (those that do not pass through soil). Amoebae were present in ten samples of basal leaves and ranged from 154–1510/g of leaf tissue. Wrapped leaves failed to yield amoebae in seven of ten trials and contained 〈4 amoebae/g of tissue. Mean values for the population density of amoebae on Oak Leaf basal leaves and Boston lettuce leaves were 484 ± 133 and 453 ± 93, respectively. The distribution of amoebae on green and white parts of leaves from both kinds of lettuce was studied. The occurrence of amoebae on rinsed, unrinsed, visibly clean, and visibly dirty samples of Boston lettuce leaves was established.

Notizen: Primary productivity, chlorophyll a, phosphorus and nitrogen nutrients, and other chemical and physical parameters were measured in 13 wetland lakes in northern lower Michigan. These lakes included several examples located in each of the four major wetland types—bogs, fens, marshes, and swamps. Of the four types, the brown-colored waters of the acid bog lakes generally had the highest levels of primary productivity, chlorophyll a, phosphorus, and nitrogen. Primary productivity correlated positively with water color, total-N, and NH3-N (α≤ 0.05). By these measures, waters of the bogs were the most eutrophic of the four types of wetland lakes. These findings would seem to contradict the generally-held concept that “dystrophic” bog lakes are extremely oligotrophic.Protozoan colonization of artificial substrate islands was monitored at each wetland site. The correlation between protozoan colonization rates (G values in the MacArthur-Wilson noninteractive model) and primary productivity, measured by 24-h light and dark bottle incubations, was significant at the 95% confidence level (r= 0.850, P= 0.001) and with water color at the 90% confidence level (r= 0.599, P= 0.084). It was concluded that protozoan colonization rate was an excellent indicator of the trophic status of wetland lakes.

Notizen: Amastigotes of different strains of Trypanosoma cruzi responded to stimulation with concanavalin A in an axenic medium by increased DNA synthesis and cell multiplication. These effects were inhibited by α-methyl mannoside. Other mitogens, i.e. phytohemagglutinin P, castor bean ricin Type II isolated from Ricinus communis, and a bacterial lipopolysaccharide, had no effect on amastigote growth. Amastigote stimulation by concanavlin A lends itself to studies on the biochemistry and cell cycle of this human pathogen.

Notizen: Spores of Nosema algerae Vávra & Undeen were exposed to 5 to 3000 KR of gamma radiation, then assayed for viability in Anopheles quadrimaculatus Say, and tested for germination in vitro. There was a dosage-dependent loss of viability between 5 and 100 KR. Immediately after exposure to radiation at dosages between 1000 and 3000 KR, the spores progressively lost ability to germinate in 0.2 M KCl, pH 9.5. Between 250 and 1000 KR spores germinated well immediately after irradiation but, over a time span of days, fewer spores were able to germinate. Gamma radiation at 1000 and 2500 also caused a decrease in intrasporal trehalose concentration. The decline in percentage germination and trehalose concentration was more rapid at the higher dosages than the lower dosages.

Notizen: Light microscopy of stained (protargol, Feulgen, aceto-orcein, methyl green-pyronin) specimens of Onychodromus acuminatus during excystment shows that the macronucleus appears during the first hour as a warped ribbon with variable density and width and with sharpened ends. One extraordinary point that reaches the cortex is frequently seen in front of a small granule where the bundle of positioning fibers arises. The macronucleus returns to its previous form, with rounded edges, at the end of cortical morphogenesis, and later divides twice. Some details of cortical morphogenesis during the excystment process are discussed.

Notizen: Aphidicolin, a mycotoxin that inhibits eucaryotic DNA polymerase alpha, blocked the growth of Toxoplasma gondii in confluent cultured human fibroblasts. Aphidicolin immediately inhibited DNA synthesis by T. gondii while it had a delayed and less dramatic effect on RNA synthesis. A mutant of T. gondii resistant to aphidicolin was isolated with the aid of mutagenesis by ethylnitrosourea. Parasite growth measured three days after drug treatment and parasite DNA synthesis measured immediately after drug treatment were, respectively, five- and four-fold more resistant to aphidicolin in the mutant as compared with the wild type parasite. The mutant had a three-fold greater capacity than the wild type to incorporate uracil into its deoxycytidine triphosphate pool. This increased deoxycytidine triphosphate pool is the probable explanation for the mutant's resistance because this deoxynucleotide is known, in mammalian cells, to reverse the inhibition of DNA synthesis by aphidicolin in a competitive manner.

Notizen: Calyptospora n. g. was erected for Eimeria funduli because the sporocyst of that species lacks Stieda and sub-Stieda bodies, has a veil supported by sporopodia, and has an anterior apical opening. A suture may be present, but it does not completely divide the sporocyst into two valves. Because C. funduli has an obligatory invertebrate intermediate host, we established Calyptosporidae n. fam. to accommodate Calyptospora and tentatively to accept Goussia. A new subgenus, Plagula, is erected for species of Goussia with a sporocystic veil not supported by sporopodia. We consider the family more primitive than Eimeriidae, Sarcocystidae, and possibly Lankesterellidae.

Notizen: Stentor niger collected in the suburbs of Hiroshima contained in its cytoplasm several hundreds of endosymbiotic algae and innumerable brownish pigment granules. The body of the ciliate was dark due to a mixture of the green endosymbiotic algae and brown pigment granules. The algae belonged to the genus Chlorella; each was enclosed in a perialgal vacuole and dispersed uniformly in the host cytoplasm from the myoneme layer inward to the center of the ciliate. The cell wall and plasma membrane of the alga enclosed a nucleus, chloroplast, mitochondrion, Golgi complex, accumulation bodies, myelinated vesicles, and many ribosomes. The chloroplast occupied more than half of the volume of the alga and contained a conspicuous pyrenoid. Algal multiplication occurred by two successive divisions of an alga, leading to four autospores within a perialgal vacuole; the walls of the vacuole invaginated to separate the autospores each into its own vacuole. Three types of pigment granules were scattered uniformly throughout the cytoplasm of the ciliate. The ultrastructure of the membranellar region, somatic cortex, and macro- and micronucleus of the ciliate are also described.

Notizen: Stages in the life cycle of a coccidium are described from the intestine of Priapulus caudatus Lamarck, 1816. Meronts, merozoites, microgamonts, microgametes, and walled and unwalled macrogametes were seen in intestinal cells. Meronts were about 8 μm long and 3–7 μm wide and produced up to seven merozoites. Free merozoites were about 9 μm long and 4 μm wide and contained about 43 subpellicular microtubules that terminated in the outer polar ring. Microgamonts were up to 23 μm long and 7 μm wide and usually were delimited by a single membrane. Microgametes were about 5 μm long, exclusive of the two flagella, about 2 μm wide, and contained a nucleus that was not uniformly dense. Macrogametes, about 6 μm in diameter, had a nucleus largely without dense chromatin. The oocyst wall formed around intracellular macrogametes to a thickness of 0.2–0.5 μm as thin, osmiophilic elements that became arranged in reticular and tubular layers. Wall-forming bodies were not seen, but fine filaments may participate in wall formation, as these were found between the outer membrane of the pellicle and the nearest wall elements. Microgametes and walled macrogametes were delivered to the lumen of the host intestine during apocrine secretion or excretion by the intestinal cells. Fertilization may occur in the intestinal lumen. Unsporulated ovoid oocysts, 18–27 μm long and 10–14 μm wide, with a 3 μm micropyle and a wall 0.6–0.7 μm thick, were passed from the host.

Notizen: Freeze-fracture procedures were used to visualize ejectisomes and adjacent plasma membrane specializations in the flagellate protozoan Chilomonas paramecium. The ejectisomes are membrane-bounded, cylindrically rolled, extrusive organelles. Small ones occur in large number beneath the plasma membrane of the body and considerably larger ones are located around the gullet membrane. The intra-membrane particle distribution is different in each type. In small ejectisomes, the portion of the membrane in contact with the plasma membrane of the body has a P-face rosette of five particles while the plasma membrane has not been observed with a rosette. Small ejectisomes and plasma membrane both contain aggregations of particles a short distance from the contact or docking site. Slightly beneath the plasma membrane is the periplastic sheet with which we speculate the small ejectisomes interact during the docking phenomenon. No obvious rosettes have been observed in large ejectisomes. Some other ejectisomal structures are presented and discussed.

Notizen: Rats infected with Eimeria nieschulzi, a coccidium that inhabits intestinal epithelium, have a lower basal inflammatory state in their intestinal mucosa eight days postinoculation as reflected by a drop in mucosal peroxidase activity and a decrease in the number of granulocytes in the lamina propria. The reduction of systemic inflammation in infected rats was assessed from a reduction in the formation of granulation tissue around a sterile cotton string implanted under the abdominal skin of the hosts. This reduced inflammatory response, both locally and systemically, occurs during the development of gamonts by the parasite and the release of oocysts from the host. These results plus the presence of normal or slightly elevated numbers of granulocytes in peripheral blood lead to the conclusion that the parasite does not affect hematopoiesis but interferes with some phase in the directed migration of leukocytes to specific sites.

Notizen: Tritiated leucine, glucosamine, mannose, and galactose were incorporated into the variant specific surface glycoprotein (VSG) of Trypanosoma congolense in vitro. The uptake of the precursors is shown by SDS-polyacrylamide electrophoresis and fluorography, by assay of the radioactivity in immunoprecipitates obtained with specific antisera, and by the isolation of the labeled antigens by affinity chromatography on concanavalin A-sepharose and isoelectric focusing. The in vitro labeled VSG exhibits the same degree of microheterogeneity as that observed in the VSG isolated from trypanosomes grown in animals. Analysis of the incorporated sugars after hydrolysis of the glycoprotein showed that glucosamine and mannose were utilized in biosynthesis of the carbohydrate moiety directly whereas galactose was converted possibly to other intermediates before being incorporated into the antigen. Tunicamycin completely prevented the incorporation of the radiolabeled sugars into the surface glycoprotein. The unglycosylated VSG with a molecular weight of 47 kDa had completely lost its size heterogeneity.

Notizen: The surface anionic groups of symbiote-bearing and symbiote-free strains of Crithidia deanei were compared by determining cellular electrophoretic mobility, by ultrastructural cytochemistry, and by identification of sialic acids by thin-layer and gasliquid chromatography. Symbiote-free Crithidia deanei has a highly negative surface charge (-0.9984 μmċs-1ċ V-1ċ cm), which is slightly reduced (-0.8527 μmċs-1ċ V-1ċ cm) by the presence of the endosymbiote. Treatment of both strains of C. deanei with neuraminidase decreased significantly the electrophoretic mobility of cells toward the cathodic pole, indicating the existence of exposed sialic acid residues responsible for the negative charge on the protozoan cell surface. Thin-layer and gas-liquid chromatography showed that N-glycolyl- and N-acetylneuraminic acids were present in both strains of C. deanei.

Notizen: The antigens that are present in the coccidian parasites Toxoplasma gondii and Hammondia hammondi were demonstrated and defined by using SDS-PAGE and immunoenzymatic techniques with 125I-labeled and unlabeled antigens of T. gondii and sera of mice infected orally or intraperitoneally with H. hammondi. All cell surface antigens of T. gondii that were labeled with 125I were recognized by antibodies in the sera of the mice infected with H. hammondi except the antigen of approximate molecular weight of 21.5 Kd. This suggests that this antigen is specific for T. gondii. Various antigens in the T. gondii-lysed antigen preparations were recognized by antibodies to H. hammondi. The number of recognized antigens increased as the infection of the mice with H. hammondi progressed. Oral infection with H. hammondi appeared to induce the formation of antibodies that recognized more T. gondii antigens than infection by intraperitoneal inoculation.

Notizen: Difluoromethylornithine (DFMO) is a specific and irreversible inhibitor of ornithine decarboxylase, an enzyme which catalyzes the first step in the biosynthetic pathway of the polyamines. We tested the effect of DFMO on the growth of Giardia lamblia, Entamoeba histolytica, and Trichomonas vaginalis. Growth of G. lamblia was inhibited by DFMO at concentrations of ≥ 1.25 mM. Culture doubling time increased with increasing DFMO concentration. Growth inhibition was reversed if spermidine was added within 53 h of addition of DFMO; no growth was observed if spermidine was added later, indicating eventual parasite death. The growth of E. histolytica and T. vaginalis, two unrelated mucosal-dwelling parasites of humans, was not inhibited by 20 mM DFMO. These studies indicate that polyamine biosynthesis from ornithine is required for growth of G. lamblia.

Notizen: Regenerating Stentor, exposed to the plant lectin phytohemagglutinin, are significantly delayed in completing oral regeneration. All of the delays are restricted to the earliest stages of regeneration prior to stage 3. The effects of phytohemagglutinin are reversible once the drug is removed. The addition of the presumed sugar receptor for phytohemagglutinin, N-acetylgalactosamine, at the start of oral regeneration could not reverse the effects of phytohemagglutinin, but the addition of excess (10 mM) extracellular calcium could. When the addition of the excess calcium was delayed for various times after phytohemagglutinin exposure, the effectiveness of the calcium in reversing the phytohemagglutinin-induced delays was reduced. Based on the mechanism of action of PHA in other cells, these results suggest that membrane proteins may be involved in controlling oral regeneration, possibly through mechanisms involving Ca++.

Notizen: A detailed molecular analysis using recombinant DNA technologies is extremely important to our understanding of the phenomena of antigenic variation in the African trypanosomes; however, by itself, it may not completely explain antigenic variation as it occurs in vivo. Several laboratories have demonstrated the ability of one variant population to replace another in vivo as well as the presence of heterogeneous populations of trypanosomes within an individual animal. These two phenomena do not permit us to explain antigen variation solely on the basis of the molecular regulation of variant antigen expression. In addition to studies in molecular biology, it will be necessary to define clearly the differences in growth rates of variant populations and the role of competition between these variants in a single anatomical site. It will also be necessary to determine the influence of various physiological environments on growth rates and the competition between the different variants of a single repertoire. It is concluded that the phenomenon of antigenic variation is a complex problem in ecology and population dynamics as well as molecular regulation. This paper is designated to examine a variety of the ecological parameters presumably involved in antigenic variation.

Notizen: Two new species of Myxozoa from the brain of the green knife fish Eigemannia virescens are described: Myxobolus inaequus sp. n. has an unusually large spore body and extremely unequal polar capsules, and Henneguya theca sp. n. has an attenuated spore encased in a sheath not previously described in other Myxozoa. Only spores of the two species were observed, and infections caused no obvious pathological changes in the brain.

Notizen: Initiation is the contact-independent phase of sexual conjugation which occurs when mature cells of Tetrahymena thermophila are shifted from growth medium to a low-salt starvation buffer. Immaturity, like high-salt starvation, restricts the ability of cells to conjugate; immature cells do not conjugate in either low- or high-salt buffers. Comparisons between sexually mature cells starved in initiation-restrictive and initiation-permissive buffers, and between immature and mature cells starved in an initiation-permissive buffer permitted the analysis of membrane protein expression correlated with mating competence. No polypeptides identified by lactoperoxidase-catalyzed iodination were found to be specific to mating-competent cells; however, several polypeptides not present in initiated cells were found to be common to the cell surfaces of immature and non-initiated cells which suggests that (1) initiation involves the removal of specific proteins from the cell surface, and (2) immaturity may be due to an inability to initiate.

Notizen: Primary turkey kidney cells and Eimeria meleagrimitis sporozoites were treated with cationized ferritin (CF) or neuraminidase (NANase), and the effects on the invasion of the cells by the sporozoites were measured. Cultures of host cells pretreated with either compound contained significantly fewer intracellular sporozoites than did control cultures. There was little additive effect if cultures were first treated with NANase and then with CF. In contrast, pretreatment of sporozoites with CF or low concentrations of NANase had no effect on invasion. The inhibition of invasion was apparently due to an interaction between treatment substances and host cell surface rather than to direct effect on the sporozoites. The CF bound to the randomly distributed anionic sites on the surfaces of both host cells and sporozoites and then rapidly aggregated. Sporozoites, probably in the process of invading cells, were invariably found with the conoid in close association with aggregates of CF on the host cell membrane. The CF on the sporozoites was apparently shed before or during invasion because all intracellular sporozoites were completely devoid of the label.

Notizen: Glycogen phosphorylase in Tetrahymena pyriformis was activated by a Mg2+ ATP-dependent process and this activation was further increased by the addition of cyclic AMP. When the enzyme activity in subcellular fractions was measured, it was largely associated with the glycogen fraction but was no longer activated by ATP and cyclic AMP. Mixing the glycogen fraction and cytosol fraction together restored the effects of ATP and cyclic AMP on phosphorylase activity. These findings suggest that glycogen phosphorylase associated with Tetrahymena glycogen granules may be regulated by cytosolic factor(s) with cyclic AMP.

Notizen: An anion exchange column of DE-52 has been used to purify Eimeria sporozoites from a post-excystation mixture of oocysts, oocyst shells, sporocysts, sporocyst shells, and sporozoites. The mean recovery from several experiments was 94% and virtually all non-sporozoite material was removed. Infectivity studies in vitro with sporozoites showed that they were viable after purification and were at least as infectious as the unpurified sporozoites; furthermore, oocysts in the crude preparation could be recovered from the DE-52 cellulose by resuspending them in a 20% (w/v) sodium chloride solution.

Notizen: The African trypanosomes bear on the outside of their cell membrane a single 10–15 nm thick coat of a glycoprotein. This glycoprotein may differ in structure in the predominant populations of parasitemic waves found in relapsing infections. Variant Specific Glycoprotein (VSG) range in MW between 53,000–63,000 d and may have variable amounts of carbohydrate attached at one, two, or several loci. Such differences in carbohydrate content may account in part for their range in molecular size. Approximately 30 C-terminal residues demonstrate isotypy; i.e. these regions fall into classes having similar amino acid sequence. Modest homology has been demonstrated in two VSGs of T. congolense arising in relapsing infections although comparison of many VSG show little or no obvious homology. More recently, lipid-associated forms of VSG have been described and it is believed that these forms may be transmembrane proteins. Different VSGs appear to have different amounts of the primary sequence which have alpha-helix-forming potential. In some VSG, in excess of 80% of the structure is helical as judged by both Chou-Fasman calculations and by circular dichroism. This raises the possibility that different VSG may have different folding patterns. The arrangement of VSG on the trypanosome surface probably places the basic amino acid-rich carbohydrate-bearing C-terminus of the polypeptide chain close to the membrane. There is some protein-protein association between VSGs for which (in T. evansi) the C-terminal tail is not required. The importance of VSG structure lies not only in the fact that the molecule mediates the phenomenon of antigenic variation but also in the recent observation that VSG may act on the cellular immune system to suppress the humoral immune responses of the host.

Notizen: During the spring of 1981, trichodinid protozoa were collected from the gills or urinary bladder of the following species of fishes of Rybinsk Reservoir, USSR, located on the upper reaches of the Volga River system: Esox lucius, Rutilus rutilus, Leuciscus idus, Blicca bjoerkna, Abramis ballerus, Pelecus cultratus, Lota lota, and Perca fluviatilis. A total of 13 species of Trichodinidae was recovered from Rybinsk fishes, among which are three new species of the genus Trichodina: T. izyumovae n. sp. from the gills of L. idus, T. borokensis n. sp. from the gills of P. cultratus, and T. kupermani n. sp. from the gills of A. ballerus. Other species of trichodinids reported are T. modesta Lom, 1980; T. nigra Lom, 1969; T. pediculus (O. F. Müller, 1786); T. prowazeki Grupcheva & Lom, 1980; T. rostrata Kulemina, 1968; T. urinaria Dogiel, 1940; T. ophiocephalus Kostenko & Karaev, 1976; Paratrichodina incisa (Lom, 1959); Trichodinella epizootica (Raabe, 1950); and Tripartiella copiosa Lom, 1959. Photomicrographs and morphometric data are presented for each species and aspects of their host and geographic distribution discussed. Trichodina algonquinensis Li & Desser, 1983 is considered a synonym of T. urinaria Dogiel, 1940.

Notizen: Morphological, ultrastructural, and reproductive studies of a suctorian suggest its designation as Trichophrya rotunda (Hentschel) as distinct from Heliophrya collini, Heliophrya rotunda, and Craspedophrya rotunda of previous descriptions. Trichophrya rotunda has a round or slightly irregular, dorsoventrally flattened body (37–73 μm) with peripheral tentacles arranged randomly within 4–13 fascicles, a central polymorphic macronucleus, and 7–21 peripheral contractile vacuoles with ventrally terminating discharge pores. The tentacles are contractile and highly flexible. The axoneme consists of microtubules forming seven curved lamellae and 35 outer microtubules, which are separated into seven groups. Deviations from this prevailing pattern include helically arranged lamellae at the points of apical and basal termination, outer ring microtubules joined in an apical connective sheath, and the presence of a basal connective sheath near the point of axoneme termination. In common with other suctorians the cortex is multilayered and the cytoplasm contains characteristic organelles such as crescentic bodies and elongate dense bodies, but the haptocysts have unusual radial projections. Trichophrya rotunda feeds readily on motile vorticellids, attachment of the tentacular knobs occurring at their trochal band. Reproduction is endogenous, producing a single, slightly flattened, oval-shaped swarmer with five equatorial kineties. The swarmer cytoplasm shows no evidence of primordia of tentacle axonemes nor any stages in development of the tentacle.

Notizen: The Wachstein and Meisel incubation medium was used to detect ATPase activity in epimastigote, spheromastigote (amastigote), and bloodstream trypomastigote forms of Trypanosoma cruzi. Reaction product, indicative of enzyme activity, was associated with the plasma membrane covering the cell body and the flagellum of the parasite. No reaction product was found in the portion of the plasma membrane lining the flagellar pocket. The plasma membrane-associated ATPase activity was not inhibited by ouabain or oligomycin, was detected in incubation medium without K+, was inhibited by prolonged glutaraldehyde fixation, and its activity was diminished when Mg2+ was omitted from the incubation medium. The Ernst medium was used to detect Na+-K+-ATPase activity in T. cruzi. No reaction product indicative of the presence of this enzyme was detected. Reaction product indicative of 5'-nucleotidase was not detected in T. cruzi. Acid phosphatase activity was detected in lysosomes. These results indicate that a Mg2+-activated ATPase is present in the plasma membrane of T. cruzi and that it can be used as an enzyme marker, provided that the mitochondrial and flagellar ATPases are inhibited, to assess the purity of plasma membrane fractions isolated from this parasite.

Notizen: A method for the isolation of Leishmania donovani amastigotes from infected hamster spleen and liver tissues is described. Over 85% of the isolated amastigotes were viable as judged by acridine orange-ethidium bromide staining and in vitro transformation to the promastigote form. A comprehensive survey of the enzymes of carbohydrate metabolism in L. donovani amastigotes and promastigotes was conducted. Amastigotes and promastigotes possess all of the enzymes of the Embden-Meyerhof pathway, hexose monophosphate shunt, and tricarboxylic acid cycle. Cell-free extracts of both forms show pyruvate dehydrogenase activity which permits entry of pyruvate into the tricarboxylic acid cycle. Both forms demonstrate an active glutamate dehydrogenase, thus linking amino acid metabolism with carbohydrate metabolism. Pyruvate carboxylase, the enzyme responsible for replenishment of C4 acids by heterotrophic CO2 fixation into pyruvate, was also demonstrable in the tissue and insect forms. In general, activities of promastigote enzymes are higher than the amastigote enzymes. Differences between the vertebrate (amastigote) and invertebrate (promastigote) forms in their potential to utilize carbohydrates as substrates would appear to be quantitative rather than qualitative.

Notizen: The calculation of purchasing power parities and quantity comparisons for a given year provides interesting information about the relative importance of countries. However, it is necessary to make these estimates annually in order to enable users to apply these parities for international comparison of annual data expressed in national currency. The paper deals with the problems related to merging spatial comparisons and temporal volume and price movements for the countries of the European Community. For these countries full information was collected in 1975 and in 1980, whereas in the intermediate years some price data were collected and price indices at a detailed level have also been collected. First the theoretical problems of consistency between the spatial results and temporal indices are discussed. Because no immediate consistency can be obtained, several methods are proposed to achieve consistency, by estimating one unique set of spatial and temporal indices. The available information for the period 1975-80 has been used in order to test the numerical differences between two sets of parities and price indices over time. Besides theoretical reasons for inconsistency, it is also necessary to take into account errors in the price observations or in the price indices. The results presented in the paper should be considered as provisional and further work will be undertaken to obtain better insights into the inconsistency between these sets of data.

Notizen: To know the size and development of the hidden or underground economy is important for policy making, mainly because the measures undertaken may be misdirected if they are based on biased official statistics. The hidden economy can be measured by considering indicators. The direct methods are based on voluntary surveys and on tax auditing and other compliance methods. The indirect estimation methods rely on the identification of residuals with respect to income and expenditures, as well as in the labor and money markets. The strengths and weaknesses of each of these measurement approaches are discussed and the resulting estimates of the size of the hidden economy are compared. A different approach to measurement is to look at the determinants leading to the existence and growth of the hidden economy. Finally, the method of “unobserved variables” allows the combination of the two approaches by simultaneously considering the determinants and indicators of the under- ground economy. The results show a considerable range of sizes for a given country and year. Though there is a broad range of size estimates, there is general agreement that the hidden economy's size has been growing for all countries over recent decades. Further progress in quantitative knowledge about the hidden economy requires the development of a theoretical model which analyses the interdependencies between the official private sector, the hidden economy, and the public sector.

Notizen: At the first residential conference of the Institute for Fiscal Studies, which was held at St. Edmund Hall, Oxford, in September 1983, Mr Stewart Bates, QC, spoke on the implications of the decision of the House of Lords in the case of W. T. Ramsay Ltd v CIR. A report of those proceedings was held over until the decision of the House of Lords in the case of Furniss, v Dawson was known. The following report is based upon Mr Bates' address and the comments of Mr Stephen Oliver, QC, Mr John Avery Jones and Mr Adrian Shipwright who spoke at a lunchtime seminar convened by the IFS on 9 March 1984 to consider the decision in Furniss v Dawson. This report does not reflect the opinions of the IFS, which has no corporate views.

Notizen: Income inequality is examined using the Panel Study of Income Dynamics and a consistent decomposition analysis. I only use inequality measures that satisfy the Principle of Transfers, have the property that a ceteris paribus increase in inequality within any subgroup increases overall inequality, and are independent of the scale of income and population. Decompositions are carried out by family size and by age of head for several definitions of income and income recipient. Whilst changing the time unit over which income is measured has a substantial impact on inequality, the effect of removing the between-age-group component of inequality is relatively slight.

Notizen: This paper discusses Austria's experiences in connection with the 1980 round of the UN International Comparison Project, in which comparisons were first made within regions and the regions then linked. Austria played a dual role, as (a) the linking country between Group I (the European Community) and Group II (selected middle and eastern European countries), and (b) the base country for Group II. The paper consists of two principal parts. The first part reports, at the 3-digit commodity level, on the success achieved in finding comparable items, both within Group II and between Austria and Group I. The second part discusses a number of methodological problems that were encountered in carrying out the comparison. Chief among these was the treatment of social services that are marketed in some countries and provided free of charge or at nominal prices in others. Other questions touched upon include the treatment of output for own consumption, rents, drugs and medicines, and tourist expenditures.

Notizen: Lack of a conceptual basis for measuring human capital investment in health has hampered efforts to expand national accounting systems to include human capital investment. This paper presents a conceptual basis for developing estimates of this health investment, an estimation methodology consistent with the conceptual basis, and preliminary estimates for the United States for 1952-78.While much work remains to be done before comprehensive estimates of investment in health are achieved, it is clear that previous estimates based on answers to the question, “What improves health?” have included some inappropriate expenditures while excluding others that should be included.The conceptual basis presented here leads to a methodology for separating health care costs (not the costs of illness) into maintenance and gross investment. Gross investment can be further separated into net investment and the sum of damages and depreciation but empirical implementation of this step is not attempted here.

Notizen: This paper describes the construction of an accounting matrix for the world economy in 1977, cast along similar lines to SNA National Accounts, but one in which trade flows replace inter-industry flows as intermediate demand. The matrix distinguishes ten regions. Institutional accounts are presented for three of these, the European Community, North America and Japan. This matrix is used to provide the basis of a linear model in which average propensities to import and consume are replaced by estimated marginal propensities. Use is made of standard estimates of the income effects of terms of trade changes in order to distinguish substitution from income effects in the model, and a means is suggested for separating the full as well as the impact effects of a terms of trade change into income and substitution effects. The estimated import equations are used to derive estimates of regional growth rates compatible with external balance in each region. Multiplier matrices are calculated from the model showing regional interdependence of the world economy reflecting the pattern of trade which is identified in the marginal propensities to import.The effects of various aid policies are calculated using the model. It is shown that the cost of aid to any region is radically altered by taking into account the feedback effects of changes in demand. A policy of tied aid pursued by EEC, North America and Japan can actually lead to an improvement in Japan's balance of payments position. Finally the effects of movements in relative prices are illustrated by means of two examples.