ALBERT

Notes: Core-protected DNA can drive only 60% of the Tetrahymena thermophila macronuclear genome into duplexes in hybridization experiments. This core-protected DNA therefore contains only a subset of the genome complexity. We interpret this to mean that a large fraction, if not all, of the genome is phased with respect to nucleosome placement. Among the sequences present in total DNA and absent from core-protected DNA are most of the sequences containing N6-methyladenine (MeAde) residues, consistent with our previous demonstration that most of these residues lie in linker DNA. We show that these results are not due to artifacts resulting from the small size of the DNA driver, nor are they due to any sequence preferences exhibited by staphylococcal (staph) nuclease. This is the first evidence that nucleosome phasing may be a bulk genome characteristic.

Notes: Book review in this Article Cox, F. E. G., ed. 1982. Modern Parasitology. A Textbook of Parasitology

Notes: Column chromatography with Biogel P2 (molecular exclusion of 1800 daltons) indicates that the transforming principle causing microstomes to become macrostomes is a small molecule. Absorbance tests show that only those fractions with high absorbance at 260 nm have biological activity, indicating that the active principle is a component of nucleic acids. Tests of purines and pyrimidines show that purines are active, with hypoxanthine having the highest activity. The combination of hypoxanthine with uridine shows a synergistic reaction. As these two compounds are the natural catabolic excretory products from nucleic acids in Tetrahymena, the fact that they induce transformation in concentrated, starving cells may be a survival mechanism allowing cannibalism to be induced when nutrients are depleted, thereby allowing the survival of the transformed cells until such time as adequate nutritional conditions are restored.

Notes: RESUME.Après résorption des structures buccales du protomonte, la stomatogenèse ne commence que sur les produits de l'avant-dernière division du tomonte. Elle se poursuit et se complète sur les tomites individualisés de la dernière division. Au niveau des extrémités antérieures des cinéties somatiques intercalaires et des extrémités rompues de cinéties bipolaires, une lère vague de proliferation des cinétosomes produit de courtes lignes, obliques, de cinétosomes isolés. Elles se transforment en lignes d'une double rangèe de cinétosomes, à la suite d'une 2ème vague de multiplication de cinétosomes. Un alignement de ces segments, procédant de gauche à droite et d'avant en arrière, constitue successivement les 3 membranelles longitudinales en doublets (M1 puis M2 et M3) ainsi que la membrane parorale, également en doublet. Une 3ème vague de proliferation cinétosomienne juxtapose une rangée de cinétosomes à droite des doublets (sauf à l'extrémité postérieure de M1 et au niveau de la parorale) transformant les promembranelles en triplets. Cette proliferation cinétosomienne se prolonge par addition d'une 4ème rangée de cinétosomes au trajet médian et postérieur de M2 et peut-ětre à M3 et par juxtapositions successives de nouvelles rangées supplémentaires à l'extrémité postérieure de M2 (flamme). Les cinétosomes des rangées droites de promembranelles portent de larges rideaux de nombreuses fibres postciliaires. Les cinétosomes des autres rangées de M2, au moins, ont également des fibres postciliaires. Entre les cils de promembranelles il n'y a pas de couche alvéolaire, ni d'épiplasme. Une résorption des cinétosomes commence à se manifester par disparition des cinétosomes de la rangée gauche de la parorale dont subsistent les cinétosomes droits porteurs de fibres postciliaires. A vec le raccourcissement de l'aire buccale la résorption s'étend aux cinétosomes postérieurs des 2 rangées droites de M1, et des extrémités antérieures des 2 (ou 3?) rangées droites dc M3. Une invagination de la dépression buccale entraǐne vers la gauche les organelles buccaux et enfonce les cinéties vestibulaires en remontant en avant et à gauche leurs extrémités postérieures tronquées. Il y a régression postéro-antérieure totale des cinétosomes de la parorale. M1 reste constituée au départ de 3 rangées ciliaires; M2 est également formée de 3 rangées ciliaires doublées postérieurement de nombreuses rangées constituant la flamme; M3 n'est finalement constituée que d'une seule rangée ciliaire. Une ultime proliferation cinétosomienne aux extrémités antérieures de cinéties vestibulaires serait peut-ětre à l'origine d'un champ allongé de nouveaux cinétosomes vestibulaires.〈section xml:id="abs1-1"〉〈title type="main"〉ABSTRACTAfter resorption of the buccal structures of the protomont, stomatogenesis begins only in the products of the penultimate division of the tomont. It continues to completion in the individualized tomites of the last division. At the anterior ends of the intercalary somatic kineties and the broken ends of bipolar kineties, a first wave of kinetosome proliferation produces short streak lines of isolated kinetosomes. These develop into lines formed of double rows of kinetosomes following a second wave of kinetosome multiplication. An alignment of these segments, proceeding from left to right and from front to rear, constitutes successively the three longitudinal membranelles in doublets (M1 then M2 and M3), and the paroral membrane, also a doublet. A third wave of kinetosome proliferation juxtaposes a row of kinetosomes to the right of the doublets (except at the posterior end of M1 and at the level of the paroral membrane) to give triplets. This proliferation is extended by addition of a fourth row of kinetosomes on the median and posterior path of M2 and perhaps M3, and by successive juxtaposition of further rows at the posterior end of M2 (flare). The kinetosomes of the right hand rows of promembranelles bear wide ribbons of numerous postciliary fibers. There is no alveolar layer nor epiplasm between the cilia of the promembranelles. Resorption of kinetosomes begins by disappearance of the kinetosomes of the left hand row of the paroral membrane; the right hand kinetosomes carrying postciliary fibers remain. With shortening of the buccal zone, resorption extends to the kinetosomes of the two posterior rows of M1 and the anterior ends of the two (or three?) left hand rows of M3. An invagination of the buccal cavity draws the buccal organelles to the left and pushes in the vestibular kineties while raising forward and to the left their truncated posterior ends. Total postero-anterior regression of the kinetosomes of the paroral membrane occurs. Membranelle 1 remains composed of three rows of cilia; M2 is also composed of three rows of cilia edged posteriorly by numerous rows constituting the flare; M3 is composed of a single row of cilia. A final kinetosome proliferation at the anterior ends of the vestibular kineties might be responsible for the extended field of new vestibular kinetosomes.

Notes: . A new procedure is described that utilizes Percoll gradients for purifying micronuclei (MIC) and macronuclei (MAC) from Tetrahymena thermophila. Separation of MIC from MAC during certrifugation in Percoll gradients occurs as a result of their difference in size rather than density. Three kinds of tests were used to evaluate the purity of the nuclei: visualization of the nuclei by light microscopy; examination of the nuclei by electron microscopy; and Southern blots of MIC and MAC DNA probed with the 5s rRNA genes or a fragment from the MAC extrachromosomal rDNA molecule. When examined under the light microscope, the isolated MIC and MAC have much lower nuclear cross contamination levels than previous methods have reported. MIC's contaminated with less than 1 MAC in 1000 MIC and MAC's contaminated with less than 1 MIC in 500 MAC can be routinely prepared. Quantitative analyses of electron micrographs gave higher estimates of cross contamination in our purified nuclei, which may, in part, be explained by the difficulty in identifying small MIC or MAC fragments. Southern blots of MIC and MAC DNA probed with 5s rDNA confirmed the level of MAC contamination in the MIC estimated by light microscopy during purification of the nuclei. The level of nucleolar contamination in the MIC was estimated at 10% by Southern blots of MIC and MAC DNA, derived from a heterokaryon with distinctive MIC and MAC Bam HI sites, using an rDNA probe.

Notes: . Polyurethane substrates were anchored near the surface of 14 lakes in the northern tip of the lower peninsula of Michigan. I wo substrates were removed from each take and taken to the laboratory after 1, 3, 6, 15, and 21 days of exposure. At the laboratory, one substrate was used for determining the number of species of diatoms and the other for protozoa. A cluster analysis of the matrix of Jaccard's coefficients for all diatom samples from all lakes showed that virtually all samples from any given lake consistently clustered together. This indicates that, with respect to species occurrence, distinct and compositionally stable diatom assemblages formed on the substrates in fewer than 21 days. Analysis of all protozoan samples from all lakes did not show such clustering, however, and the correspondence of clusters for protozoan and diatom communities for the 14 lakes was not particularly good. This suggests that the link between the two groups at the species level is not particularly strong during the early phases of artificial substrate colonization.

Notes: . Herpetomonas megaseliae, Crithidia fasciculata, and Leptomonas collosoma from culture survived gut passage in Anolis carolinensis following their ingestion by this lizard. Maximum persistence of H. megaseliae in lizards, as detected by fecal culture, was seven days. No invasion of tissues by H. megaseliae could be detected by means of sectioned material, stained impression slides, or cultures inoculated with material from organs. Crithidia fasciculata was evident in cloacal fluid for up to three days in wet mount preparations. Leptomonas collosoma was observed in feces 24 h after the organisms were fed to lizards. Both C. fasciculata and L. collosoma were cultured from feces of lizards fed the parasites 24 h earlier. Herpetomonas megaseliae was differentiated in lizard feces, with greater than 40% of the forms observed being paramastigotes or opisthomastigotes. Truncate, semispherical forms resembling choanomastigotes were seen, but the kinetoplast was posterior to the nucleus in some of these. Many forms showed extensive coiling of the axoneme within the body of the flagellate. Choanomastigotes and spheromastigotes of C. fasciculata and promastigotes, sphero-mastigotes and amastigotes of L. collosoma were also observed in the feces.

Notes: . To answer whether Blepharisma hyalinum is truly unpigmented, the organism must be established in culture as pointed out by Giese in 1973. Accordingly, the present study deals with B. hyalinum kept in culture since its isolation in 1975. The organism still remains colorless after growth in the dark; however, it contains cortical granules resembling pigment granules in colored species. A comparative study was therefore undertaken of B. hyalinum and B. steini; both species have a compact macronucleus, though of different shape. Crude pigment was extracted with acetone from organisms grown in the dark for three weeks and the maxima were measured by absorption. Purified pigment was obtained from TLC-plate preparations and the absorption maxima were measured after removal of lipids with chloroform. No maxima characteristic of blepharismin were found in extracts of B. hyalinum, but these were present in extracts of B. steini. Electron microscopy of the cortical region revealed membrane-bound granules in both species; these granules differed in content but not in their capacity to extrude. In B. hyalinum all granules had a homogenous electron-dense substructure; in B. steini the granules had a net-like granulated substructure of varying electron density. This difference corresponds to that published on “pigment” granules in albino and pigmented strains of B. undulans. Our conclusions are that B. hyalinum is unpigmented (and a valid separate species) and that the cortical granules may serve other functions than that of storing blepharismin.

Notes: . Sporozoites of Eimeria vermiformis from the mouse were first seen in the epithelial cells of villus tips and the crypts of Lieberkühn four hours after inoculation (HAI). They were always within a parasitophorous vacuole. By 12 HAI, most were in crypt epithelial cells between the basement membrane and host cell nucleus. The sporozoites in the villus tips had 26 subpellicular microtubules, two polar rings, two preconoidal rings, two refractile bodies surrounded by amylopectin-like granules, a lamellar Golgi apparatus, numerous micronemes, and rhoptries. The sporozoites in the crypt cells had fewer amylopectin-like granules, micronemes, and rhoptries. A nucleolus was visible, as were pieces broken off from the posterior refractile body. Later, the sporozoites folded over to become U-shaped; the infolded membranes fused; and then the inner membranes disappeared so that spherical meronts were formed. Folding sporozoites were first seen 16 HAI and persisted until 52 HAI.

Notes: . From an intermittent stream in College Station, Texas, a Paramecium was isolated that did not appear to belong to any recognized species. On the basis of nuclear and whole-body morphology, it can be assigned to the Paramecium aurelia species-complex, and it can be distinguished from other members of that complex on the basis of mating-type reactivity and isoenzyme patterns. These characteristics are felt sufficient to justify a new species assignment. The new species has been named Paramecium sonneborni n. sp. in honor of the late Dr. Tracy M. Sonneborn of Indiana University.

Notes: . Enzyme electrophoresis was exploited to identify stocks of paramecia previously not identified to particular species. Stocks collected in India and one from Panama belong to Paramecium jenningsi, while others collected in Panama or in Brazil are assignable to syngen 2 of P. multimicronucleatum on the basis of similarity of their esterase and acid phosphatase phenotypes. Inclusion of these doubled the numbers of stocks available in the two species, thereby facilitating examination of intraspecies variation and comparison of particular features of intraspecies variation found for the P. aurelia complex. Variant stocks were observed in P. jenningsi and in syngens 2, 3, and 4 of P. multimicronucleatum. In some cases the variant lacked the enzyme; in others, a change in mobility of the enzyme occurred that resulted in an electrophoretic form similar to one common in another species. Unique phenotypes were displayed by the variants of syngen 2 in P. multimicronucleatum. Hypervariability for Esterase B was observed in this syngen, where, in addition, several subtypes were seen for three other esterases. Unique phenotypes and hypervariability were also noted in P. biaurelia. Clustered variations were observed in these species and in the P. aurelia species. Unlike the situation for members of the aurelia complex, where lack of geographical differentiation between stocks in the same species is a unique feature, some such differentiation does occur in P. multimicronucleatum-2. The frequency of variant stocks in P. jenningsi was similar to that observed in the aurelia sibling species. In contrast, a significantly higher frequency of variant stocks was found in syngens 2, 3, and 4 of P. multimicronucleatum.

Notes: The trophont stage in the life cycle of Ichthyophthirius multifiliis was studied in the electron microscope. Surface ridges contain up to 24 ridge microtubules, disposed as a ribbon. Kinetosomes show the classic morphology of 9 triplets of microtubules. Associated with each kinetosome is a kinetodesmal fibril, originating in proximity to triplets 5, 6, and 7, and having a 30 nm periodicity; 3 to 5 postciliary microtubules, originating between triplets 8 and 9; and up to 3 transverse microtubules, originating at triplet 4, as well as a parasomal sac. Each cell is partially enclosed by a system of 3 “unit” membranes: the outer limiting membrane, and the outer and inner alveolar membranes. The last two membranes define the alveolar sac. Mucocysts, each with a dense core, are present in large numbers. The contractile vacuole system includes the contractile vacuole, associated tubules and vesicles, injection canals, a discharge canal, and a pore. Microtubules abound in the walls of the contractile vacuole, injection and discharge canals, and in the region of the pores, where both ring and radial microtubular arrangements are noted. The ultrastructure suggests that I. multifiliis is more closely related to Tetrahymena pyriformis than to Paramecium aurelia.

Notes: Experiments with Tetrahymena thermophila using ferritin probes revealed that these cells take up ferritin conjugated to antibodies (not directed against Tetrahymena) much more readily than they do ferritin or cationized ferritin. The massive and rapid uptake of antibody-ferritin offers certain advantages for studies of endocytosis and membrane flow in cells of this type, and the method may be applicable to other types of protozoa as well.

Notes: The mechanism of action of antileishmanial compounds is poorly understood. Ultrastructural changes in Leishmania tropica within human macrophages exposed in vitro to Pentostam, pentamidine, amphotericin B, WR 6026, ketoconazole, and Formycin B were examined in these experiments. In Pentostam-treated cultures, some organisms exhibited diminished definition of mitochondrial and other membranes, while other organisms had completely disintegrated. Pentostam-exposed macrophages demonstrated loss of membrane definition in the absence of further alterations; it is therefore hypothesized that impaired macrophage membrane function may contribute towards the effect of this drug against macrophage-contained organisms. Leishmania parasites in pentamidine-treated cultures initially demonstrated swollen kinetoplasts and fragmentation of the kinetoplast DNA core. The initial observed effect of the other four drugs on the parasites was cytoplasmic condensation. These ultrastructural studies suggest that all five non-antimonial drugs may have different mechanisms of action than antimony (Pentostam) against Leishmania.

Notes: Immobilization antigens from 12 serotypes of three stocks of Paramecium tetraurelia and from one serotype of one stock of P. primaurelia were isolated and purified. Purified proteins were cleaved with cyanogen bromide, and the patterns of the fragment peptides were determined by electrophoresis on SDS-polyacrylamide gels. It was shown that each of the serotypes of stock 51 of P. tetraurelia has an antigen that produces a characteristic and unique pattern. Consequently, the antigens can be identified by their patterns. Antigens from the allelic serotypes tested had identical patterns. The method is sensitive enough for the investigation of small sample volumes, and useful as a simple biochemical technique for the identification of serotypes.

Notes: Nutritional requirements of Acanthamoeba polyphaga (strain PD) were compared to those reported for A. castellanii. Although A. polyphaga and A. castellanii have essentially the same minimal amino acid requirements–arginine, methionine, leucine, isoleucine, and valine–A. polyphaga cannot utilize acetate as sole carbon source, but A. castellanii can if the medium is supplemented with glycine.

Notes: Classification at the species level has been difficult in the genus Acanthamoeba. The taxonomic designations of a number of strains are in doubt and new approaches to classification are needed. We describe the use of electrophoretic patterns obtained with restriction enzyme digests of mitochondrial DNA as a basis for one new approach. Results from analysis of ten strains of A. castellanii, two of A. polyphaga and one of A. astronyxis are discussed. Examples both of nucleotide sequence diversity and of sequence conservation have been found among strains with the same species designation. Five strains from Europe, North America and New Zealand had identical digestion phenotypes with five enzymes; consequently, very similar nucleotide sequences are predicted. All are pathogenic to humans or mice. The mtDNA sequences of eight remaining strains are predicted to differ from this cluster and, in most cases, from each other at least as much as in sibling species of Paramecium aurelia.

Notes: When Tetrahymena furgasoni (W) are stained by the silver impregnation technic. a relatively small percentage of them show cortical argentophilic bands or stripes that are intermeridional in position. The number and arrangement of the bands as well as their distinctive appearance and abrupt daily peaks of occurrence render them distinct from other recognized components of the argyrome. The term “virgulene” is proposed as a name for this feature.

Notes: The differentiation of Trypanosoma cruzi epimastigotes into trypomastigotes was studied in diffusion chambers sub-cutaneously implanted in mice. Using epimastigotes of the Tulahuén strain, transformation was first evident at 16 h after implantation and reached its maximum (92% trypomastigotes) by 24 h. Shortly before their differentiation into trypomastigotes, epimastigotes were found to develop resistance to lysis by the alternative pathway of complement. Furthermore, implantation of stationary-phase (as opposed to log-phase) parasites resulted in the accumulation of large numbers of complement-resistant epimastigotes in the chambers. These observations suggest that epimastigotes pass through a complement-resistant transitional stage before differentiating into trypomastigotes and that transformation may require cell division. In a further series of experiments, epimastigotes recovered 7 h after implantation in mice were found to differentiate into trypomastigotes when cultured in vitro for an additional 17 h at 37°C. This observation indicates that the events which trigger the morphologic transformation of epimastigotes into trypomastigotes can be dissociated operationally from the differentiation process itself.

Notes: Morphological, cultural, and biochemical criteria that have been used in describing lower trypanosomatids, genera Blastocrithidia, Crithidia, Leptomonas, Herpetomonas, Rhynchoidomonas, and Phytomonas are reviewed. Kinetoplast structure, carbohydrate utilization, electrophoretic mobilities of isoenzymes, and kDNA fingerprinting are among the recommended criteria for species differentiation. Temperature, pH, and osmolarity tolerance are useful growth parameters. Generic placement may be assisted by the determination of nitrogenous excretion products and ornithine-arginine cycle enzymes.

Notes: Ten antiprotozoal drugs were tested in vitro against four axenic strains of the intestinal parasite Blastocystis hominis. Inhibitory drugs in order of effectiveness were emetine, metronidazole, furazolidone, trimethoprim sulfamethoxazole, 5-chloro-8-hydroxy-7-iodo-quinoline (Entero-Vioform), and pentamidine. Moderately inhibitory were two quinolines other than iodochlorhydroxquin. These were chloroquine and 5, 7-diiodo-8-hydroxy-quinoline(Floraquin). Diloxanide furoate was not inhibitory. Paromomycin and other antibiotics were not inhibitory. Entero-Vioform and metronidazole have been effective in human and higher primate diarrhea caused by B. hominis.

Notes: Groups of mice were given an intraperitoneal injection of one of six monoclonal antibodies to Toxoplasma gondii, a mixture of equal amounts of five monoclonal antibodies to T. gondii, or the murine myeloma protein MOPC 21, and challenged with either a highly virulent or moderately virulent parasite strain. Two monoclonal antibodies (FMC 19 and FMC 22) conferred total protection against the moderately virulent challenge, with all mice surviving, whereas 90% of control mice died. FMC 19 and FMC 22 also conferred significant protection against the highly virulent challenge as indicated by a prolonged mean time to death (MTD) of immunized compared with control groups of mice. One monoclonal antibody (FMC 23) and the mixture of five antibodies gave significant protection against the moderately virulent challenge only. Passive immunization with dilutions of FMC 22 antibody indicated that the lowest serum titer needed to confer significant protection to mice against a moderately virulent Toxoplasma challenge was 1/640. Mice challenged with highly virulent tachyzoites that had been preincubated with FMC 22 had a significantly longer MTD than mice challenged with highly virulent tachyzoites that had been preincubated with MOPC 21 or phosphate buffered saline, pH 7.2 (PBS). Immunoprecipitation and autoradiography of radiolabeled tachyzoites confirmed that FMC 19 was directed against a 35,000 molecular weight (mol. wt.) antigen and FMC 22 was directed against a 14,000 mol. wt. fraction. The potential for use of single antigens as protective immunogens in preventing toxoplasmosis is raised.

Notes: The heliozoan Echinosphaerium nucleofilum produced about 75 times 103 floating cells per 19-cm culture dish per day when fed the green flagellate Chlorogonium elongatum. This method yields enough cells for usable quantities of subcellular fractions. Heliozoa were lysed in a detergent mixture containing stabilizing reagents, and axonemal bundles of axopodial microtubules were isolated from the lysate by differential centrifugation. Polyacrylamide gel electrophoresis in sodium dodecylsulfate showed two prominent bands tentatively designated alpha- and beta-tubulin. Apparent molecular weights were 51.8 times 103 and 48.1 times 103, respectively. As assayed by electron microscopy of negatively stained whole mounts, the microtubule bundles splintered readily, although glycerol tended to inhibit this fraying. Intermicrotubule bridges could be observed in some axonemal splinters.

Notes: The antipsychotic drugs chlorpromazine, pimozide, and penfluridol caused a 50% inhibition of growth of Tetrahymena at concentrations of 4.5, 5.5, and 1.5 μM, respectively. The degree of growth inhibition was dependent on the concentration of cells; higher drug concentrations were needed to produce inhibition of denser cell cultures. Binding studies with penfluridol showed that 50% growth inhibition resulted when approximately 50 μmoles of drug were bound per 106 cells. A 20-min preincubation of cells with chlorpromazine (14.7 μM) inhibited DNA synthesis by 46%, and with penfluridol (4 μM) DNA synthesis was inhibited by 27%. The incorporation of labeled thymidine into the thymidine triphosphate pool was inhibited by chlorpromazine but not by penfluridol, indicating that the drugs produce their growth inhibitory effects by different mechanisms. TDP kinase activity was demonstrated in a particle-free fraction of the cells. Its enzymatic activity was not affected by added chlorpromazine, penfluridol, or calmodulin, suggesting that inhibition of DNA synthesis by these drugs may be a consequence of growth inhibition.

Notes: The protozoan Blepharisma japonicum showed negative phototaxis caused by transient reversal of the direction of ciliary beat and changes of swimming velocity induced with varying intensities of light. The ciliary reversal occurred at 1–2 sec after a sudden increase in light intensity. When light intensity was decreased, no response was observed. Moreover, the ciliates swam fast in light areas but slowly in dark areas; the mean velocity of swimming was 80 μ m/sec at 5 × 102 lux but reached about 400 μMm/sec at 5 × 103 lux. In addition, the cell body elongated in response to light application; the mean length of the body was 308 μm at 5 × 102 lux, which increased to 397 μ m at 104 lux. Such body elongation seems to contribute to rapid swimming. Negative phototaxis may be an important behavior in B. japonicum because the organisms are killed by exposure to strong light.

Notes: Freeze-fractured cells of three marine species of Euplctes (E. crassus, E. raikovi, and E. rariseta) show bristle cilia with patterned arrays of intramembranous particles. Such arrays are essentially of three types, in different positions along the bristle shaft. One array is located near the bristle base and shows a plate-like shape. It appears in a close spatial correspondence with the lasiosome network, which is a structure consisting of interconnected electron-dense bodies lying in between the peripheral axonemal doublets and the bristle membrane. The second type of array, apparently typical of only E. raikovi, consists of eight to ten longitudinal rows of particles that occupy most of the intermediate portion of the bristle. The third type of array appears differently shaped in different species and occurs at the bristle apex.

Notes: An ultrastructural study on mitosis in the marine dinoflagellate Prorocentrum minimum is described. Early in mitosis the nuclear membrane invaginates in the area of the Golgi apparatus. Additional membrane-lined channels form within the nucleus as the Golgi apparatus separates and moves toward opposite spindle poles. Microtubules appear within the channels and make contact with distinct kinetochore-like structures on the cytoplasmic side of the channels adjacent to the site of chromosome attachment. By mid-mitosis two or three parallel channels dissect the nucleus perpendicular to the suture plane of the cell. Chromosome separation thus occurs perpendicular to the suture plane. An additional group of microtubules extends posteriorly from the flagellar apparatus towards the nucleus but has no apparent role in mitosis. Mitosis in P. minimum is compared to that of P. micans and to other dinoflagellates.

Notes: . The ciliated protozoon Tetrahymena patula can be grown in a chemically defined medium supplemented with a suitable lipid. High purity natural phosphoiipids; mono-, di-, and triglycerides: and free fatty acids are suitable lipids. The more complete lipids appear to serve simply as nutritionally convenient sources of fatty acids. T. patula can also be grown in the synthetic medium supplemented with cholesterol or other sterols in lieu of fatty acid containing lipids. Supplementation with either ethanolamine or choline permits suboptimal growth of the ciliate in a lipid-free synthetic medium. No other water soluble compound, of a variety that were tested, permitted growth of the ciliate in the lipid-free medium.

Notes: . The pathway of de novo pyrimidine biosynthesis in the rodent parasitic protozoa Babesia rodhaini has been investigated. Specific activities of five of the six enzymes of the pathway were determined: aspartate transcarbamylase (ATCase: E.C. 2.1.3.2): dihydroorotase (DHOase: E.C. 3.5.2.3): dihydroorotate dehydrogenase (DHO-DHase: E.C. 1.3.3.1); orotate phosphoribosyltransferase (OPRTase: E.C. 2.4.2.10); and orotidine-5′-phosphate decarboxylase (ODCase: E.C. 4.1.1.23). Michaelis constants for ATCase, DHO-DHasc. OPRTase, and ODCase were determined in whole homogenates. Several substrate analogs were also investigated as inhibitors and inhibitor constants determined. N-(phosphonacetyl)-L-aspartate was shown to be an inhibitor of the ATCase with an apparent K, of 7μM. Dihydro-5-azaorotate inhibited the DHO-DHase (K, 16 μM) and 5-azaorotate (Ki, 21 μM) was an inhibitor of the OPRTase. The UMP analog, 6-aza-UMP (Ki, 0.3 μM) was a potent inhibitor of ODCase, while lower levels of inhibition were found with the product. UMP (Ki, 120 μM) and the purine nucleotide, XMP (K1, 95 μM). Additionally, menoctone, a ubiquinone analog, was shown to inhibit DHO-DHase.

Notes: . A heat-stable chemoattractant has been isolated from bacterial cultures. This component has a molecular weight in the range of 500–1000 daltons, is produced by both Gram-positive and Gram-negative bacteria, and serves equally well as an attractant for both the bacterial feeding Paramecium and for its natural predator, Didinium. Aspects of the ecological relationship between bacterial feeding ciliates and their ciliate predators are briefly discussed with respect to responses of both predator and prey to such a common chemotactic bacterial factor.

Notes: . The ultrastructure of the cortex beneath the fission furrow of dividing Stentor coeruleus was examined using scanning and transmission electron microscopy. During division, basal bodies, axonemes, and km fibers beneath the furrow were absorbed near the moving primordial oral apparatus, and a circumferential band of microtubules and filaments was formed at the base of the furrow. The location and orientation of this fibrous band suggest that it may be an important component of the cytokinetic machinery. Treatment with vinblastine sulfate (4 × 10-5 M) disrupted the circumferential microtubules and blocked division, which is consistent with this hypothesis.

Notes: . A new ciliate genus Trichodoxa n. g. and two new species (T. genitalis n. sp., T. phalli n. sp.) are described and figured. These are only the second and third species of the family Trichodinidae to be described from the genital system of terrestrial molluscs. Only one tier of cilia surrounds the basal disc. This character, the course of the infundibular ciliature. structure of the coronal denticles, and structure of the border membrane differentiate the new genus from others in the family.

Notes: . Up to five zones of acid phosphatase activity appear in gels after electrophoresis of detergent-treated extracts from 13 of the 14 species of the Paramecium aurelia complex. The overall pattern is somewhat similar for all species: differences in intensity and mobility of individual zones permit the grouping of these sibling species into eight groups. All 14 species can be identified using the procedure of enzyme electrophoresis, although two of them are more similar than is usually the case. Problems of misclassification are discussed in terms of the nature and frequency of variants. With the judicious choice of enzymes used to screen new stocks, these problems can be circumvented. Species relationships are updated using 11 enzymes. A dendrogram constructed from the matrix of genetic distances shows four clusters of species: (i) P. biaurelia, P. triaurelia; (ii) P. primaurelia, P. pentaurelia, P. sexaurelia, P. novaurelia; (iii) P. septaurelia, P. undecaurelia, P. tredecaurelia, P. quadecaurelia; and (iv) P. tetraurelia, P. octaurelia, P. decaurelia, P. dodecaurelia. Distances between the species are large, on the order of the differences between Drosophila species. The species are characterized by an extraordinary lack of geographical differentiation and great morphological similarity, which contrasts strongly with the molecular differentiation.

Notes: The growth rate of Tetrahymena setosa cells is stimulated significantly by as little as 0.1 μg and optimally by about 1 μg of ergosterol per ml of medium. Cell yields in the stationary phase are, however, not perceptibly affected by increasing sterol concentrations. Ergosterol, in concentrations that stimulate growth optimally, does not cause a reduction of tetrahymanol synthesis. The latter process is impaired only at much higher ergosterol concentrations. Epicholesterol and coprostanol inhibit ergosterol-stimulated growth competitively. It is concluded that the trace amounts of sterol needed by T. setosa do not serve to replace tetrahymanol but function in some other manner, probably unrelated to the control of membrane fluidity. This conclusion supports the views advanced earlier by Holz, Erwin, Wagner & Rosenbaum.

Notes: Gossypol, a polyphenolic compound from the cotton plant, immobilizes and structurally alters cultured Trypanosoma cruzi epimastigotes. Ultrastructural changes observed in gossypol-treated parasites were first detected in the kinetoplast and mitochondrion. At 50 μM concentration, much disorganization was evident after 5 min of incubation. With 25 μM gossypol, the same effect occurred after 30 min. Most epimastigotes were rounded, containing various membranous structures that could not be related to known cell components.

Notes: Methods of transmission and the effects of temperature and mites on ageledeme development of Herpetomonas were examined in populations of Drosophila melanogaster maintained in the laboratory. Herpetomonas was observed in feces of infected adults taken from population cages and in the vomitus of clean flies shortly after feeding on a saline suspension of flagellates. Free-swimming flagellates were found in the moist areas of food cups. Adult D. melanogaster became infected when they fed on flagellates taken from the endoperitrophic space, the ectoperitrophic space or the Malpighian tubules.At 25°C the flagellates infected approximately 90% of the host population within 20 days. The high transmission rate was prematurely disrupted if host populations were subjected to changes in temperature. Free-swimming flagellates did not appear to be affected at these temperature changes. Food mites (Tyrophagus) established in the growth media of the fly nearly eliminated the Herpetomonas from Drosophila populations.

Notes: Thirteen bohor reedbuck Redunca redunca wardi (Thomas, 1900) from Kenya and Tanzania, ten common reedbuck Redunca arundinum arundinum (Boddaert, 1785) from Zimbabwe and 34 mountain reedbuck Redunca fulvorufula fulvorufula (Afzelius, 1915) from South Africa were sampled. Twenty-six protozoan species have been identified, 18 in the bohor reedbuck, which included seven entoninia, two new Diplodinium species, but no holotrichs. In the southern reedbuck 13 species were recorded, which included two entodinia, and 11 diplodinia including the two new species; holotrichs were also absent. The mountain reedbuck which is a mixed feeder as opposed to the grazers had 22 species including two holotrichs.

Notes: Grass shrimp (Palaemonetes pugio) fed liver containing sporulated oocysts of Eimeria funduli permitted development of sporozoites that became infective to a variety of killifishes. The shrimp's gastric mill mechanically ruptured the oocysts. Sporozoites then excysted through an opening in the sporocyst, and by 12 and 13 h postinfection (p.i.) numerous empty sporocysts and free sporozoites occurred extracellularly in the intestine of the grass shrimp. Even at 5, 7, 8, 11, 46, 79, and 83 days p.i., and presumably for many months, numerous sporozoites still occurred free in the alimentary tract or between intestinal cells. The coccidium did not infect killifish at either 2 or 4 days p.i., but did at 5 days; after release from the sporocyst, it became more elongate with a distinct nucleus and two relatively large refractile bodies. Infections of E. funduli resulted in about one half of the fish that were fed either entire hepatopancreas or tips of hepatopancreas from experimentally infected shrimp. Feeding either the entire alimentary tract proximal to the first abdominal segment or any portion of that section from experimentally infected shrimp produced infections in nearly all tested fish. Feeding portions of the cephalothorax without any attached hepatopancreas or alimentary tract failed to produce an infection. Feeding killifish with wild grass shrimp from an enzootic area produced infections in only a fourth of the fish sample; however, feeding experimentally infected wild, laboratory-reared, and juvenile grass shrimp produced infections in nearly all fish. Palaemonid shrimps other than P. pugio also can serve as intermediate hosts for E. funduli, and these shrimps include Palaemonetes vulgaris, P. paludosus, P. kadiakensis, and Macrobrachium ohione. In contrast, a penaeid shrimp, mysidacean, amphipod, and crab fed liver with sporulated oocysts did not produce infections when fed to killifish.

Notes: Thirty axenically grown reference strains belonging to 15 different Acanthamoeba spp. were investigated for isoenzyme patterns by agarose isoelectric focusing in the pH range 3–10. Zymograms of acid phosphatase, leucine amino peptidase, malate dehydrogenase, propionyl esterase, glucose phosphate isomerase, phosphoglucomutase, and alcohol dehydrogenase were compared. The same strains were also analyzed for protein patterns separated by agarose isoelectric focusing in a pH gradient of 5–8. The results suggested changes in taxonomy within morphology group II of Pussard & Pons. Acanthamoeba paradivionensis becomes a synonym of A. divionensis. Although this species seems to be related to A. rhysodes, it could not be concluded that the species names are synonyms since the type strain of A. rhysodes was not available for comparison. In the subgroup A. polyphaga–A. quina–A. lugdunensis, A. lugdunensis becomes the species name for pathogenic strains of this subroup, A. quina for the nonpathogenic strains, while A. polyphaga is the species name for an atypical strain. Two strains of A. castellanii showed different zymograms from strain Neff of this species, but related protein patterns. In group III, A. pustulosa is found to be a synonym of A. palestinensis, while one strain of A. lenticulata is also found to belong to the A. palestinensis species. All other species names in both morphology groups could be retained as valuable, on the basis of the techniques used. Group I was not investigated, as axenic cultures could not be obtained.

Notes: The effects of ultraviolet radiation (λ= 254 nm) on the kinetics of encystment of the hypotrichous ciliate Laurentiella acuminata and the structure of resting cysts obtained from irradiated precystic cells are reported. High doses of UV-radiation caused a delay of encystment with a linear increase in the average time for obtaining 50% of encystment (EN50). Resting cysts with abnormal cyst walls were obtained when precystic cells were irradiated in the exposure range 720 to 960 J/m2. The cystic layer (mesocyst) was approximately twice as thick (6.5 μ m) as normal (3.7 μ m). Microscopical observations of abnormal cysts revealed the presence of two complete mesocysts, and the absence of the spines characteristic of the ectocyst. The UV-dependent effects on the cyst wall were gradually corrected in successive generations of the irradiated cells.

Notes: The “mucigenic” or “muciferous” bodies of Peranema trichophorum are further characterized here as unique extrusive organelles, the mucocysts. Intracellular and ejected mucocysts have characteristic shapes that may represent different developmental stages. Mucocysts found near the Golgi apparatus are membrane-bounded, elongate, tubular structures with amorphous contents of low electron density. Subpellicular mucocysts are often aligned with pellicular striae and have dense contents, which are separated by an electron-lucent zone from granular material at the tips. Ejected mucocysts are uniform in structure and consist of an inner tube with helical striations, an outer tube with a diamond-shaped pattern, and a dense middle band. Fine fibrils, visible only after mucocyst discharge, emanate from the tips. Mucocysts may also protrude through the pellicle and discharge mucilaginous materials into the medium. Acid phosphatase activity is localized within the subpellicular mucocysts, suggesting that they may be involved in release of hydrolytic enzymes into the medium.

Notes: Morphogenetic events during division, physiological reorganization, and postraumatical regeneration, the last being induced both chemically and microsurgically, were studied by light microscopy on protargol-impregnated specimens of the hypotrichous ciliate, Laurentiella acuminata. Parakinetal stomatogenesis, from transverse cirrus-1 during division and reorganization, changes during regeneration to a parakinetal one which characterizes more primitive members of Hypotrichida in the S. O. Stichotrichina, but solely when the AZM is damaged. These morphogenetic events a) confirm the previous inclusion of L. acuminata among the Oxytrichidae on the basis of its morphological characters and indicate that it is a primitive species of this family related with the Stichotrichina through genera Pleurotricha and Paraurostyla; b) suggest a synthetic model that explains both the positioning and timing of cortical morphogenesis in the cell cycle. The key point of this model is the attribution to the AZM of a repressive capacity on the stomatogenic area, the last one being positioned according to the system of gradients of morphogenetic activity proposed by Jerka-Dziadosz to explain location of primordia in urostylids. This repression is manifested not as a gradient, as indicated by De Terra, but as a long-term repression limited to a certain distance. Simultaneous repression and stimulation occurring in a growing cortex with the AZM remaining constant in size could explain the critical ratio, buccal cortex/somatic cortex, at which stomatogenesis is triggered as indicated by De Terra.

Notes: The formation of Babesia equi sporozoites in the salivary glands of three tick species (Hyalomma anatolicum anatolicum, H. a. excavatum, Rhipicephalus turanicus) was studied by electron microscopy. The development was identical in all three vectors. On the 8th day post repletionem kinetes of B. equi had invaded alveoli of the nymphal salivary glands and were transformed to sporonts bounded by a single membrane. The sporonts were polymorphous bodies each with a highly lobed nucleus and numerous mitochondria. These stages persisted during ecdysis of the tick nymph to the adult stage. After attachment of these newly molted adults to a new host the formation of sporozoites was completed within five days. The sporonts occupied most of the infected alveolus and were extensively divided into cytoplasmic portions of various size. On the 4th day after attachment of the tick, sporozoite-anlagen, into each of which a nucleus and a mitochondrion were incorporated, appeared at the periphery of the sporonts. An apical complex with a polar ring, rhoptries, and micronemes was formed at the tip of each protruding anlage. Finally thousands of pyriform sporozoites (3.0 × 1.2 μm) filled the hypertrophied alveolus. This development is similar to sporogony in the genus Theileria.

Notes: The encystment of Laurenliella acuminata was divided into five stages: stage A (precystic semitransparent cell with dark-globules), stage B (precystic transparent cell), stage C (precystic pigmented cell), stage D (spherical shape without cyst wall) and stage E (young resting cyst), on the basis of observations of changes in morphology and pigmentation during encystment. The duration of these stages was also established. Observations by electron microscopy confirmed that the cyst wall, composed of four layers, is derived from different kinds of precursors which are synthesized “de novo.” The ectocyst precursors are composed of stacks of between 5 and 12 small thin plates or discs; these stacks are about 0.9 μm in length and 0.06 μm in height. The mesocyst precursors are fibrillar bodies of variable shapes, about 2.4 μm in maximum length and 0.12–0.16 μm in diameter. These precursors appear in the cytoplasm of the precystic cell during the first precystic stage (stage A). The endocyst precursors are rounded bodies surrounded by a fine membrane, and their contents appeared similar to the endocyst. The granular layer precursors are spherical bodies about 0.1–0.2 μm in diameter, surrounded by a double membrane presenting ribosomes adhering to its outer membrane. Both endocyst and granular layer precursors are observed in the precystic cytoplasm from stage B. On the basis of ultrastructural studies, a formation and growth model of the cyst wall of the hypotrichous ciliate Laurentiella acuminata is proposed.

Notes: The cortical development during cell division and the interphase ultrastructure of the marine interstitial hypotrich Certesia quadrinucleata is described using light microscopy and both scanning and transmission electron microscopy. Membranelles are paramembranelles; postciliary microtubules from rightmost membranellar kinetosomes line the buccal cavity and separate parallel arrays of pharyngeal discs that border the cytopharynx. A large paroral membrane is present; an endoral membrane is absent. Alveolar plates lie within alveolar membranes except in regions where organelles and organellar complexes (cirri, the condylopallium, dorsal bristles, membranelles, and the paroral membrane) emerge from the cortex. Muciferous-like bodies attach to the plasma membrane in these regions. Dorsal bristles possess transverse and postciliary microtubules as well as kinetodesmal fiber like those of other hypotrichs. Lasiosomes are present. A unique bulbous structure—the condylopallium—protrudes from the anterior right of the cell. The morphogenetic pattern is euplotine in that cortical development begins in one latitudinal zone, and the oral primordium of the opisthe develops within a subsurface pouch apart from the frontal primordia. Microtubular bundles appear beside (later attached to) developing frontal anlagen; they disappear after cirri are in final interphase locations. Although possessing unique characters, Certesia shares a close phylogenetic relationship with Euplotes.

Notes: During development of Acanthamoeba castellanii in a non-nutrient medium, the pattern of synthesis of proteins changes. Comparison of in vivo and in vitro patterns of protein synthesis reveals concomitant relative increases of five proteins, indicating a control of synthesis of these proteins at the level of the RNA content. The decrease in the overall rate of protein synthesis and relative decreases in the synthesis of actin and ribosomal proteins during development, not accompanied by equivalent changes in the content of mRNA, suggest control mechanisms also at the level of translation. Patterns of ribosomal proteins do not change qualitatively during encystation, indicating that the inhibition in the overall rate of protein synthesis and the formation of inactive monosomes is not controlled by this mechanism; however, phosphorylation of one ribosomal protein, S 3, is observed occasionally during encystation. Phosphorylation of S 3 is also detected after transfer of stationary phase cells into fresh nutrient medium. It was found that only such cells having RNA of aberrant properties are able to phosphorylate S 3 after transfer into fresh nutrient medium. Since these changes in the property of RNA are never observed in cysts, in which phosphorylation of S 3 sometimes occurs, it is concluded that either other alterations in the properties of RNA than those detected or other parameters are responsible for changes in phosphorylation of S 3.

Notes: The two closely related hypotrichous ciliate species, Stylonychia lemnae and S. mytilus, have been compared with respect to their isoenzyme patterns, their macronuclear DNA banding patterns, and micronuclear DNA banding patterns after restriction enzyme digestion. Since macronuclear DNA contains mainly protein-coding sequences and since the micronuclear DNA patterns represent mainly the repetitive fraction of the genome, these results, together with the isoenzyme patterns, reflect differences on three different levels of molecular evolution between morphologically very similar species. Each of the three methods allows an unequivocal identification of each of the two species. Intraspecific variation seems to be greatest among the repetitive sequences of the micronuclear genomes. By using the isoenzyme data and the formula of Nei (19) the genetic distance between the two species is calculated and compared with the results from other protozoa and different Drosophila species. Despite their morphological similarity, the two species show a considerable amount of evolutionary divergence on the three molecular levels which have been investigated.

Notes: Promastigotes of Leishmania move progressively up a concentration gradient of: various sugars, specific sugars attracting individual species of Leishmania; serum albumin and another unidentified constituent of serum; hemoglobin; and a factor generated by promastigotes in NNN medium. The movement of promastigotes up a concentration gradient of serum is optimal at a pH of 6.4 to 6.8 and a temperature of 28°C and above. Cholinergic and adrenergic agents did not affect the attraction of serum for promastigotes. and cyclic nucleotides, inflammatory mediators, and macrophage products were not chemotaxic. It is postulated that the sugar chem-otaxins influence the movement of promastigotes from the sand fly midgut to the esophagus, and serum chemotaxins may play a part in the entry of promastigotes into the skin of a mammal from the proboscis.Macrophages, the host cell of the obligate intracellular Leishmania species, were not attracted to any product of promastigotes. When, however, promastigotes interact with serum, complement is activated to form C5a which is chemotaxic for macrophages. Activation of complement by promastigotes is, at least partially, by the alternate pathway. Other chemotaxins resulting from promastigote interaction with serum may also be present. Promastigotes may also produce inhibitors of C5a activity.

Notes: Transmission of Cryptobia salmositica occurred when infected and uninfected rainbow trout were held in the same tank. In tanks where infected and uninfected fish were allowed to mix freely, 67–80% of the uninfected fish acquired detectable infections by the 27th week. None of the control fish in another tank was infected. In another tank where the infected and uninfected fish were separated by a wire screen, 9 of 20 uninfected fish acquired detectable infections by the 22nd week. This is the first demonstration of direct transmission of a hemoflagellate via the water medium in aquatic vertebrates. Cryptobia salmositica was found in the mucus on the body surface of 9 of 10 fish examined 6 weeks after infection. These parasites were infective and some of them were morphologically similar to those in the blood or peritoneal fluid. It is suggested that the vascular species of Cryptobia were originally ectoparasitic on fishes and that these ectoparasitic species were descended from the free-living Procryptobia.

Notes: Zoites of Sarcocystis muris were recovered from the skeletal muscles of infected mice by trypsin digestion. Extracts of zoites prepared by freeze-thaw, Triton X-100 (0.1%), or a combination of the two treatments contained antigenic components. Testing of these antigens by agar gel diffusion and immunoelectrophoresis against sera from infected mice showed one major precipitin band.SDS-polyacrylamide-gel electrophoresis (SDS-PAGE) of the extracts revealed at least eight detectable polypeptides ranging in molecular weight from 10,000 to 220,000. The antigenic components of the extract were identified by labeling the parasite surface with [125I] and precipitation of the [125I]-labeled antigens with immune sera. Analysis of the immunoprecipitates by SDS-PAGE and autoradiography revealed three antigens with molecular weights of 27,500, 43,000 and 90,000. The smallest of these was the predominant antigen as suggested by labeling intensity.

Notes: In P. chabaudi, hemoglobin digestion occurs in two ways: micropinocytosis and cytostomal phagocytosis. Both mechanisms lead to the formation of digestive vesicles which evolve to pigment vesicles containing hemozoin crystals. We used ultrastructural enzyme cytochemistry to detect and localize endoarylamidase and aminopeptidase activity. In P. chabaudi, these two enzymes are at first detected at the level of cytoplasmic ribosomes. When pinocytic vesicles appear, enzyme activity is localized at the membrane of the newly formed vesicles. Then, the labelling extends to the vesicle contents where it becomes very prominent. In the late trophozoite, enzymatic activity decreases and is no longer detected. In B. hylomysci, no endoarylamidase activity can be detected. Aminopeptidase is noted in the cytoplasm, the labelling being heavier in the growing trophozoites than in the younger stages. No vesicles or pigment can be observed. We thus conclude that aminopeptidase or endoarylamidase are synthesized in the cytoplasm of P. chabaudi and migrate to the digestive vesicles where hemoglobin digestion occurs. We do not know whether Babesia degrades hemoglobin since it does not produce residual pigment. It could feed from small peptides or amino acids coming from or through the stroma of the red blood cell.

Notes: Neutral lipids, particularly triglycerides, accounted for the major decrease in the total lipid content in Paramecium cells that occurs with culture age. Sterols, triglycerides, and steryl esters were the major classes of neutral lipids in cells and isolated cilia. Free as well as high concentrations of esterified sterols were detected in purified ciliary membrane preparations. Stigmasterol and 7-dehydrostigmasterol were the major components of both free and esterified sterols of cells and cilia; however, when cholesterol was present in the growth medium, it was desaturated to 7-dehydrocholesterol and incorporated into cellular and ciliary lipids. Free fatty acids from cells and triglycerides from cells and cilia were low in polyunsaturated fatty acids and reflected the composition of fatty acids in the culture medium. An exception was the reduced concentration of stearate in triglycerides from whole cells. Greater than 50% of triglyceride fatty acids from cilia were saturated. The fatty acid compositions of cellular triglycerides and ciliary steryl esters did not change with culture age, but those of cellular steryl esters and ciliary triglycerides did change. In comparison with phospholipids, these neutral lipid fatty acid compositional changes were smaller. The sensitivity of these stigmasterol-containing cells to polyene antibiotics indicated that they were killed by nystatin 〉 filipin 〉 amphotericin B. The unexpected finding of high concentrations of steryl esters in ciliary membrane preparations is discussed.

Notes: Sporogenesis of Sphaerospora angulata occurs in the lumen of renal tubules, and of Sphaerospora carassii sporogenesis occurs in the gill epithelium of carp (Cyprinus carpio) from Hungarian pond farms. In infected fish, the lumen of the renal tubules is filled with disporous pansporoblasts of S. angulata. Spores are formed through the participation of paired valvogenic and capsulogenic cells, and a dikaryotic sporoplasm, all of which lie in the cytoplasm of an envelope cell. The polar filament is formed through the apparent invagination of components of the elongate external tubule into the capsular primordium, coupled with the incorporation of dense material from the lumen of the primordium and external tubule. The cytological events leading to spore formation in monosporous pansporoblasts of S. carassii are similar to those of S. angulata and most other species of Myxosporea thus far. While neither parasite appears to induce severe pathogenesis, they may contribute to morbidity in concurrent infections with other microorganisms. Since spores of S. angulata and S. carassii are not formed in plasmodia and the earliest stage observed in this study was 2-celled, earlier stages of these parasites must occur elsewhere in the carp host.

Notes: . Inhibition, inactivation, pH, and kinetic studies using both homogenates and purified lysosomal fractions of Paramecium caudalum and of P. tetraurelia were carried out to examine the lysosomal acid phosphatase (AcPase) and its relationship to p-nitrophenylphosphatase (pNPPase), glucose-6-phosphatase (G6Pase), and 5′-nucleotidase (AMPase). The results generally support the idea that Paramecium cells contain a distinct lysosomal AcPase with a broad substrate specificity. The hydrolysis of glucose-6-phosphate (G6P) and adenosine 5′-monophosphate (AMP) was shown to be due to this enzyme, suggesting that true G6Pase and AMPase may be lacking in these two species; however, some hydrolysis of AMP at pH 7.5 catalyzed by an unknown soluble enzyme distinct from alkaline phosphatase and Na+-K+-ATPase was observed. Since the hydrolysis of p-nitrophenylphosphate (pNPP) at acid pH was also shown to be due to AcPase alone, pNPPase could be used as a rapid assay for Paramecium AcPase. At an alkaline pH, however, this activity was catalyzed by an alkaline phosphatase located in the cytosol fraction. P. caudatum AcPase was shown to have kinetic properties similar to those of purified rat liver and human prostatic AcPase and to have relative substrate affinities in the order of G6P 〈 β-glycerophosphate 〈 pNPP 〈 AMP. These different substrate affinities might account for the observed differences in the inhibition of the four lysosomal activities by NaF, L(+)-tartrate, and molybdate, all of which inhibited the hydrolysis of G6P, β-glycerophosphate, and pNPP competitively, but which exhibited a noncompetitive inhibition of a mixed type with the hydrolysis of AMP.

Notes: . Experiments have been carried out on Gregarina garnhami to examine some of the factors that may be significant in gliding. Suspension of gregannes in Ficoll showed that substrate contact is essential. Reflection interference microscopy shows that there are fluctuating surface/substrate contacts, but it is not necessary for the whole of the undersurface of the cell to be in close contact with the substrate. Gliding is always accompanied by the formation of a mucus trail. The effects of the drugs amphetamine and ephedrine on mucus trail formation and gliding have been examined. Lateral undulations of the epicyte folds have previously been implicated in grcgarinc gliding, but G. garnhami does not exhibit lateral undulations of the epicyte folds as it moves. The folds are predominantly straight with indications of varicosities or swellings along the length of the folds. These observations are discussed in relation to gliding movement.

Notes: . Cyclic AMP binding activity was determined in the ciliate Tetrahymena pyriformis NT-1 strain. The fractions having the binding activity were eluted in a single peak coincident with a protein kinase activity. Although metal ions were not essential for activity, the binding was slightly activated by Mg2+ or Ca2+. The binding activity was sensitive to temperature, ionic strength, and pH of the reaction mixture and was decreased by treatment of the cytosol protein with trypsin or by heating at 100°C. The binding was specific for cyclic AMP, with an estimated apparent Kd of 40 nM. When the cyclic AMP binding activity in subcellular fractions was measured, an increase in the activity of ciliary, mitochondrial, and microsomal fractions was observed during the transition from the exponential to the stationary phase of cell growth, whereas no significant change occurred in the binding activity of the whole cell homogenate. These results suggest that the redistribution of cyclic AMP binding proteins may be implicated in the regulation of cyclic AMP concentration in the cell.

Notes: . Forty-five axenically grown algal (sensu lato) species representing six divisions—that is. 13 Chlorophyceae, 14 Chrysophycophyta, five Dinophycophyta, seven Cryptophycophyta, two Rhodophycophyta, and four Cyanochloronta—were aseplicaily presented separately as potential food sources to the marine helerotrich ciliate Fabrea salina under standardized algal number, medium, lighting, and temperature. The algae can be placed into three groups based on their effect on the intrinsic growth rate of the ciliate. Nutritious: Rhodomonas lens, cryptomonad LIS1, Dunaliella parva, Prasinodadus marinus, Chroomonas salina, D. tertiolecta, Chaeloceros galvestonensis, D. primolecta, Phaeodactylum tricornutum, D. salina, Isochrysis galbana, Cylindrothecaclosterium, cryptomonad strains M2, WH2 & FSA, Chroomonas sp., P. lubricus, and Peridinium trochoideum. Maintamers: Cyanobacterium strain Tigriopus blue green, P. triquetum. Monochrysis lutheri, Exuviella gracilis, Platymonas tetrathele. Cyclotella caspa, Crypthecodinium cohnii, Prasinocladus C5 strain, D. viridis, Nannochloris occulata, Tetraselmis gracilis, Anacystis marinum, Rhodosorus marinum, and Thalassiosira pseudonana. Nonnutritious: Stichococcus immobilis, Hymenomonas sp. strain 150, Syracosphaera sp. strain 181, Tetraselmis verrucosa, Thalassiosira fluviatilis, Microcoleus chthonoplastes, Synechococcus sp., Pavlova gyrans, Prymnesium parvum, Coccolithus huxleyi, Olisthodiscus luteus, Amphidinium carterii, and Porphyridium aerugineum. There was no apparent relationship between a given taxon and the nutritional value of the group, with the possible exception of the Cryptophycophyta.

Notes: RESUME. Dans la région antérieure de Spirochona gemmipara, l'emploi combiné de la microscopie à contraste interférentiel (No-marski), des colorations au protargol et de la microscopie électronique à transmission révèle l'existence d'un appareil cytoproctal et d'un système excréteur (“contractile vacuole complex”), lesquels ont souvent été confondus entre eux ou avec le cytopharynx. L'appareil cytoproctal comprend un orifice externe situéà la base de la collerette, un canal cytoproctal long d'environ 20 μm limité par une pellicule alvéolaire, et le cytoprocte proprement dit. Le système excréteur est formé de 6 à 8 canaux sinueux pouvant mesurer jusquà 20 μm de long et s'ouvrant chacun par un pore situé sur la face interne de la collerette, parmi la ciliature. L'ostium, c'est-à-dire l'orifice profond de chaque canal, est en relation avec une vacuole dans laquelle aboutit un spongiome tubulaire bien développé. Bien que profondément enfoncés dans le cytoplasme, le cytoprocte et les ostia du spirochone ne semblent pas fondamentalement diffêrents des organites correspondants décrits chez Paramecium et chez Tetrahymena.

Notes: . The structure and ultrastructure of the chitinous lorica of Eufolliculina sp. are described. The lorica is produced from precursor material secreted by the motile swarmer immediately after settling. This material is located in numerous vesicles found in the cortical region of the cells and is secreted by exocytosis. Initially, material is secreted from the ventral part of the cell to produce the attachment plate of the lorica. After this, exocytosis occurs over most of the body surface as the ampulla part of the lorica is constructed. During the later stages of lorica formation, secretion is mainly limited to the anterior of the cell as the neck is formed. The lorica is shaped mainly by the action of the cilia and by the behavior of the cell. While the neck is being formed, the anterior part of the cell is deformed by a local accumulation of cytoplasmic vacuoles. This deformation is employed in shaping the neck. No changes were detected in the organization of the cortical infraciliature during the first stages of lorica formation, but they do occur after the neck has been produced and as the swarmer develops into the sessile form.

Notes: . Isoenyme electrophoresis of three different enzymes was used to compare 16 strains of vahlkampfiid amoebae and a strain identified as a slime mold. The strain designated as an Echinostelium sp. was found to be an isolate of Naegleria fowleri on the basis of zymogram type and other characters, confirming Cursons & Brown's similar conclusion drawn in 1975. The N. fowleri strains examined expressed the typical zymograms of the species. The N. gruberi strains in this study presented two distinctive groups of patterns that were different from the two previously reported types for N. gruberi. Each of the remaining species studied formed single distinctive groups by which they could be identified.

Notes: . Forty-eight stocks in Paramecium jenningsi, syngens 1–5 of P. multimicronucleatum, P. caudatum, P. primaurelia, P. biaurelia, and P. tetraurelia were grown axenically and tested for their esterases and acid phosphatases using starch gel electrophoresis. The five esterases and the acid phosphatases previously characterized in species of the P. aurelia complex were also found in P. jenningsi, and three to four of the esterases and the acid phosphatases were found in the P. multimicronucleatum species complex and in P. caudatum. Additional subtypes were observed for each of the enzyme phenotypes in these new (though here unnamed) species of Paramecium. Two of the new acid phosphatase subtypes, which depart radically in mobility and in pattern, were found in syngen 3 of P. multimicronucleatum and in P. caudatum. Except for syngens 1 and 5 in P. multimicronucleatum, the degree of similarity between syngens 1, 5 and 2, 3, and 4 appears to be very low—perhaps even lower than that seen for species in the aurelia complex. More realistically, the syngens of P. multimicronucleatum should be considered as separate species although they are not here given separate taxonomic names. Limited sharing of subtypes occurred between species in different species complexes. This observation suggests that the molecular distances between species complexes may be even greater than between species within a complex.

Notes: Book reviewed in this article: Martinez-Palomo, Adolfo 1982. The Biology of Entamoeba histolytica. Ristic, M. & Kreier, J. P., eds. 1981. Babesiosis. Krylov, M. V., ed. 1981. The Evolution and Phylogeny of the Unicellular Animals. Petrushevskaya, M. G. 1981. [Radiolaria of the Order Nasselaria of the World's Oceans.] Amos, W. B. & Duckett, J. G., eds. 1982. Prokaryotic and Eukaryotic Flagella. Matthes, Dieter 1982. Sesshafte Wimpertiere: Peritricha, Suctoria, Chonotricha. Kaestner, Alfred, ed. 1980. Lehrbuch der Speziellen Zoologie. Band I: Wirbellose Tiere. Rosowski, James R. & Parker, Bruce C., eds. 1982. Selected Papers in Phycology II. Raikov, Igor B. 1982. The Protozoan Nucleus: Morphology and Evolution.

Notes: In early log phase cultures of several of the drug-resistant mutants of Crithidia fasciculata that we have previously obtained, a high percentage of cells attach in pairs at the base of the flagellum. This process, which we have termed “flagellar adherence,” lasts for several hours in some cases and occasionally involves changes in cell morphology. The attachment occurs optimally in gently agitated cultures. Flagellar adherent pairs can be disassociated by vigorous agitation; the pairs reappear in the culture within one to three h after disassociation. These paired forms can be clearly distinguished from the normal cell division forms. Clones of flagellar adherent-competent mutant strains are uniformly able to form these pairs in culture. A low percentage of flagellar adherent forms can be induced in wild type cells by glucose starvation.

Notes: Indirect immunofluorescence using anti-myosin rabbit sera showed myosin localized in a characteristic pattern at the anterior pole of Toxoplasma gondii. This polar fluorescent staining was abolished by pre-absorption of the anti-sera with myosin extracted from avian muscle. Both intracellular and extracellular T. gondii showed similar patterns when formaldehyde-fixed, but neither showed polar fluorescence when acetone was used as the sole fixative. Immunofluorescent staining of live T. gondii revealed no polar fluorescence, suggesting that myosin is not present on the outer parasite membrane. Anti-myosin serum did not prevent host cell invasion and plaque formation in the presence of human complement. Inhibition of contractile proteins with cytochalasin D inhibited T. gondii motility and infectivity in a plaque formation assay. The pattern of polar fluorescence described here resembles the IgM-associated polar staining frequently detected in human sera, but we believe it is a different phenomenon because human sera that showed such staining retained their activity after pre-absorption with avian myosin. The unusual localization of myosin at the anterior pole of T. gondii tachyzoites may play a role in the function of anterior organelles, which are thought to facilitate the invasion of host cells.

Notes: Epidinium caudatum has an anterior vestibulum containing the adoral zone syncilia (AZS) on an extrusible peristome. The cytopharyngeal structures include a funnel-shaped arrangement of nematodesmata, longitudinal and transversely oriented microtubular ribbons all of which are located in the peristome, a structure which also contains filamentous phagoplasm. The origins of the microtubular ribbons indicate affinities to the rhabdos type of cytopharynx. The peristomal base is continuous with the tubular esophagus, the region connecting the two being ensheathed by a fibrous layer and low density cytoplasm. The esophagus has a microtubular/microfilamentous wall. A distinct cytoproct with associated myonemal structures occurs posteriorly. The skeletal plates consist of a large number of interconnected, variably shaped platelets and may have dual skeletal and storage functions. The endoplasm is more vesicular than the ectoplasm, the two separated by a fibrous boundary layer. The five-layered cortex has an external glycocalyx, a plasma membrane with two subtending membranes, homogeneous, microtubular, and microfilamentous layers. The syncilia of the AZS are mounted in a U-shaped band on the peristome with transversely oriented kinetics consisting of kinetosomes linked by a sub-kinetosomal rod. There is a bifurcated kinetodesma, dense support material forming a lateral spur with associated transverse microtubules, and postciliary, interkinetal, and occasional basal microtubules, nematodesmata, and a subciliary reticulum. A barren, possibly vestigial, somatic infraciliature consists of non-ciliated kinetosomes and a basal striated fiber with associated basal and perpendicular (cortical) microtubules.

Notes: The surface morphology of Entamoeba histolytica trophozoites of HM 1:IMSS (axenic and monoxenic) and HK9 (axenic) strains cultured on plastic and MDCK cell substrates was examined using scanning electron microscopy (SEM). The conditions for processing trophozoites were determined by comparing the SEM observations with the morphology of living amebas examined by light microscopy. The most frequent surface differentiations in all the amebas observed with SEM were lobopodia. Round cytoplasmic projections were found in approximately half of the axenic amebas. Endocytic stomas and filopodia were more common in monoxenic cultures while the uroid was found in only 2–8% of all examined amebas. The basal surfaces of the trophozoites, involved in both attachment and cytolysis, showed no unusual features, except for the presence of a small number of short filopodia at the outer edge. No differences were found in the morphology of amebas grown on artificial and natural substrates. These observations demonstrate that there are significant quantitative differences in the surface morphology of cultured trophozoites of different strains of E. histolytica and that association with bacteria produces an increase in the relative number of surface specializations of the parasite.

Notes: Two-dimensional gel electrophoresis was used to compare the protein composition of normal (D strain) and symbiont-containing (xD strain) A. proteus. Over 500 different peptide spots could be identified on a typical gel of cytosol proteins. In addition to differences in a few minor peptides, one prominent polypeptide with an isoelectric point of about 5.5 and a molecular weight of about 29,000 was present in the cytoplasm of symbiont-containing amoebae and in the endosymbionts but not in D-strain amoebae. When endosymbionts were removed from xD-strain amoebae, the xD-specific polypeptide also disappeared, suggesting that it is produced by the endosymbionts.

Notes: The adoral ciliary zone of the rumen ciliates, Entodinium spp., was observed topographically in the SEM. The upper side of the anterior end of the body was indented by the vestibulum, which had cilia arranged on its right wall and ribs along the left wall. The adoral ciliary zone could be divided into at least two arrangements. The outer ciliary zone had many membranelle-like structures, which consisted of cilia arranged radially from the body axis. Each membranelle-like structure consisted of two rows of about eight cilia each lining up in a single file. It was, however, different from a typical membranelle, because its cilia were connected with the vestibular cilia and were arranged not spirally but on a plane. These cilia extended toward the outside because of the projecting cytoplasm from which they originated. In contrast, the cilia of the inner ciliary zone were aggregated to form relatively unsystematic bundles. Since the vestibular opening was slanted on the upper side of the body, the ciliary bundles were thick on the lower side and sparse on the upper side of the body. Neither outer nor inner ciliary zones completely surrounded the vestibular opening. The ciliature started from the left side of the vestibular opening, encircled the lower side of the body, and entered the vestibulum from its right side. The functions of these two types of ciliary arrangements are discussed.

Notes: SYNOPSIS. Broad scope investigations have allowed a study of the intestinal parasitic protozoa of the Kenya baboon Papio doguera in its natural habitat as well as an opportunity to follow the intestinal protozoan populations in these primates held in captivity. Samplings indicate that the amoebae found in the baboon are essentially the same as those which commonly occur in man. Balantidium coli is frequent in wild baboons but is self-limiting in animals after a few weeks in captivity. The flagellates Chilomastix mesnili and Giardia lamblia were detected in captive but not in wild baboons; the presence of the latter constitutes a new record for Papio doguera.

Notes: SYNOPSIS. Experimental observation of the pathogenicity of some strains of Hartmannella plus the observation of human meningo-encephalitis due to small amebas which had a structure compatible with that of Hartmannella in the tissues has suggested the concept of respiratory amebiasis followed by cerebral and other complications.Until recently no cultural evidence was available to identify positively the amebas in the human cases. This report summarizes the isolation of Naegleria sp. (HB-1) from human spinal fluid by mouse inoculation followed by tissue culture of the infected mouse brain. C. Butt and his associates, who submitted this material to us, isolated the Naegleria on agar medium with Escherichia coli without antibiotics at 37 C.The new isolate failed to grow on the medium previously suggested by us for Hartmannella. HB-1 is virulent for laboratory animals and has a structure in the tissues which more resembles the amebas in the human tissue than the amebas in experimental Hartmannella infections of mice. Naegleria and Hartmannella are both potential pathogens for normal animals and man. A clinical laboratory method to detect Naegleria as well as Hartmannella is herein suggested.

Notes: SYNOPSIS. Reticulocytosis, stimulated by the destruction of red blood cells by phenylhydrazine, altered the course of infection of both Plasmodium chabaudi and P. berghei in the mouse. P. chabaudi, lacking a preference for reticulocytes, was adversely affected when young cells were present in abundance. Parasitemias diminished and most of the animals survived the otherwise fatal infection. P. berghei preferentially invaded reticulocytes to the extent that the parasitemia became contained largely in the reticulocyte population. This was accompanied by a delay in time to death.

Notes: SYNOPSIS. Uronema nigricans, a hymenostome ciliate, is redescribed by modern technics. Anatomic studies were made on 4 strains treated primarily with the Chatton-Lwoff silver impregnation technic. Particular attention was given to the buccal apparatus and its importance to generic assignment in the order Hymenostomatida.

Notes: SYNOPSIS. A hyperparasite probably related to some lower protistan was found in the cytoplasm of Entamoeba suis Hartmann. These were very minute bodies with a central Feulgen-positive dot, the nucleus, and a bordering cytoplasmic ring with an alcian blue-positive reaction. This organism appeared to interfere with the synthesis of DNA & RNA in the host amoeba as reflected in its relative stainability with Feulgen or pyronin-methyl green. The suggestion is that the parasitized amoebic cysts were most likely rendered nonviable.

Notes: SYNOPSIS. Cell-free preparations from Crithidia jasciculata carried out protein synthesis as measured by 14C-leucine uptake (optimum ∼ 10 mM Mg++) and poly U-directed 14C-phenylalanine uptake (optimum ∼ 16 mM Mg++). Characteristics of the system and sucrose density-gradient patterns of ribosomes were investigated. The charging and transfer reactions—the 2 main steps in protein synthesis—were inhibited by stilbamidine, hydroxystilbamidine, pentamidine, quinapyramine (Antrycide), and suramin.

Notes: SYNOPSIS. Cohnilembus verminus, a marine hymenostome ciliate, is described from a culture taken at Eniwetok. Anatomic studies were made on specimens treated primarily with the Chatton-Lwoff silver impregnation technic.

Notes: SYNOPSIS. Eimeria callospermophili was found in 6 species of ground squirrels and the white-tailed prairie dog. The hosts included Spermophilus armatus from Utah and Montana, S. richardsoni from Montana and Wyoming, S. beecheyi from California, S. lateralis and S. variegatus from Utah, and S. tridecemlineatus and Cynomys leucurus from Wyoming. Infections were generally transmissible from each species of ground squirrel to S. armatus and S. richardsoni. Oocysts from C. leucurus caused infections in S. armatus and S. richardsoni. No infections were found after inoculation of E. callospermophili oocysts into least chipmunks (Eutamius minimus), Mongolian gerbils (Meriones unguiculatus), or laboratory rats; however, excystation occurred in these animals. Resistance to infection did not develop in S. armatus, S. richardsoni, or S. variegatus, but did occur after 5 or more infections in S. lateralis. Eimeria callospermophili had little or no effect on the host in S. armatus, S. lateralis, or S. variegatus, but caused bloody diarrhea in severely infected individuals of S. richardsoni.The oocysts had an oocyst residuum consisting of several distinct bodies, which later coalesced to form a large homogeneous body. Each sporozoite had an unusually large refractile body. In experimentally infected specimens of S. armatus the prepatent period and patent period lasted for 5 and 9 days, respectively. Mature 1st-generation schizonts, first seen 2 days after inoculation, had 8–12 merozoites. Mature 2nd-generation schizonts, first seen 3 days after inoculation, had an average of 18 merozoites which were smaller than those of the 1st generation. Mature gametes were 1st seen 4 days after inoculation. Mature microgametocytes were only slightly larger than mature macrogametes.

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

Notes: SYNOPSIS. Eimeria eumopos n. sp. (Coccidiida, Eimeriidae) from a Colombian bat Eumops trumbulli (Chiroptera, Molossidae) is described. This is the first recorded coccidium in a bat from the western hemisphere, and the sixth bat coccidium species described to date. The unsporulated oocysts in the bat feces are 30.9–24.0 by 28.9–23.2 μ (near 28.8 × 26.1 μ). Their outstanding feature is the pronounced pitting of the thick brownish oocyst wall.

Notes: SYNOPSIS. An electron microscope study of Plasmodium coatneyi in the rhesus monkey supplied information on the fine structure of trophozoites, gametocytes and of the host cell. The trophozoites resemble other mammalian malaria parasites. They do not have typical protozoan mitochondria, but instead a concentric double-membraned organelle, which, it is assumed, performs mitochondrial functions. They feed on the host cell by pinocytosis, engulfing droplets of erythrocytes thru invaginations of the plasma membranes at any region of the cell or thru the cytostome. Digestion of hemoglobin takes place in small vesicles pinched off from the food vacuole proper.Gametocytes can be clearly distinguished into macro- and microgametocytes. Macrogametocytes are covered by 2 plasma membranes, the inner one appearing thicker in some places. The cytoplasm is filled with Palade's particles and has numerous vesicles of endoplasmic reticulum and toxonemes. In microgametocytes most of the inner membrane is thickened, the cytoplasm has few Palade's particles and vesicles of the endoplasmic reticulum and does not have toxonemes.Erythrocytes with trophozoites are irregularly scallop-shaped and have elevated points with knob-like protrusions covered by a double membrane. If these protrusions are sticky they might be in part responsible for clumping and arresting the schizonts and segmenters in the capillaries. The host cell contains numerous Maurer's clefts which in some instances are continuous with the membranes of the parasite suggesting that they might originate from them.

Notes: SYNOPSIS. Mice, segregated in groups according to sex and age from 5 to 21 weeks, and randomly presented, were inoculated in one continuous process with a trypanosome suspension prepared from a Trypanosoma brucei subgroup stabilate of such a dilution that about 50% of the mice might be expected to become infected. No statistically significant difference occurred between groups, either with regard to sex or to age.Significant alterations in the proportions of mice infected did, however, occur in relation to inoculation order. The inoculation process occupied 12–197 minutes after removal of the stabilate from −79 C storage. Essentially, infectivity rose initially to a peak between 30 and 80 minutes, and then fell off, but was not abolished at the end of the experiment.

Notes: SYNOPSIS. Observations were made on the fine structure of Paramecium bursaria and its intracellular Chlorella symbionts. Emphasis was placed on the structure of the algae and structural aspects of the relationship between the organisms.The algae are surrounded by a prominent cell wall and contain a cup-shaped chloroplast which lies just beneath the plasma membrane. Within the cavity formed by the chloroplast are a large nucleus, a mitochondrion, one or more dictyosomes, and numerous ribosomes. The chloroplast itself is made up of a series of lamellar stacks each containing 2–6 or more thylakoids with a granular stroma and starch grains intercalated between the stacks. The thylakoid stacks of mature algae are frequently more compact than those of recently divided algae. A large pyrenoid is located within the base of the chloroplast. It is made up of a granular or fibrillar matrix surrounded by a shell of starch. The matrix is bisected by a stack of 2 thylakoids. Prior to the division of the chloroplast the pyrenoid regresses; pyrenoids subsequently form in the daughter chloroplasts thru condensation of the matrix material and the reappearance of a starch shell. This shell appears to be formed by the hollowing-out of starch grains already present in the chloroplast stroma. Accordingly, in this case, starch moves from the stroma to the pyrenoid.The algae are located thruout the peripheral cytoplasm of the Paramecium. Each alga is located in an individual vacuole except immediately following division of the algae when the daughter cells are temporarily located in the vacuole which harbored the parental cell. Shortly thereafter the vacuole membrane invaginates, thereby isolating the daughter algae into individual vacuoles. Degenerating symbiotic algae are seen; because these are frequently found in vacuoles with bacteria, they are presumed to be undergoing digestion. Due to the conditions of culture these algae could have been either of intracellular or extracellular origin.

Notes: SYNOPSIS. Electron-microscopic observations were performed on 2 species of Volvox, one similar to V. globator, the other to V. aureus. The former has distinct protoplasmic connections in the adult coenobium and specific structures, named “medial bodies,” in the connections just at the intersection with the middle lamella. The medial body is disk shaped, about 800 mμ in diameter, and is composed of 3 parts, 2 dense outer layers and an intermediate less dense zone. In the latter species, the connection and medial body were not seen. On the other hand, it was commonly seen in both of them that in younger, dividing gonidia neighboring protoplasts were connected with each other by protoplasmic bridges. The bridges are undoubtedly formed due to incomplete cell separation in the division of a gonidium. The structural difference in the adult coen***bium between the 2 species emerges just after inversion of the coenobium. In the globator type the medial body appears just after inversion, and the connection remains unruptured all thru life. In the aureus type, it seems that the connections are withdrawn or degenerate immediately after inversion. It is discussed whether protoplasmic continuity is really maintained by the connection or not in the freeswimming coenobium of Volvox.

Notes: SYNOPSIS. Plasmodium lophurae hemozoin (malaria pigment) is a heme-containing protein which is distinctly different from hemoglobin and hematin by immunologic, spectrophotometric, fingerprint, heme-iron, gel filtration, and starch gel electrophoretic analyses. The calculated average molecular weight of P. lophurae hemozoin is ca. 40,000. Hemozoin contains at least 3 antigenic components and shows some indication of cross-reaction with hemoglobin.

Notes: SYNOPSIS. In tryptone media, optimal growth of nonphotosynthetic Euglena gracilis var. bacillaris on glucose occurred with 1% (w/v) glucose at pH 3.5, and required a previous adaptive period in glucose medium.In short term metabolic experiments, glucose uptake was greatly stimulated by small concentrations of tryptone or succinate; effects of shaking suggested that CO2 has a similar stimulatory effect. Glucose utilization was highly dependent on glucose concentration, with an apparent threshold at about 2 mM and increasing steeply with glucose concentration above this value. In tracer experiments, about 90% of the glucose carbon consumed was assimilated, and about 10% released as CO2.Glucose did not stimulate respiration even during rapid glucose utilization. Tracer studies indicated oxidation of endogenous substrates was depressed by an amount which just compensated for the respiration due to glucose.The conditions which allowed rapid glucose utilization by “resting”E. gracilis var. bacillaris were the same as those known previously to be required for growth on glucose. It was therefore concluded that these factors act directly on the main pathways of glucose metabolism.

Notes: In the course of the nearly two decades since the revised SNA was developed, the role of pensions and insurance in the developed western economies has been significantly altered. The United Nations System of National Accounts (SNA) is not fully consistent in its treatment of pension and insurance transactions. This paper examines whether, in view of the changed institutional context, a modification of the SNA treatment of this complex of flows would be desirable. It investigates the impact on household income and saving of adopting a somewhat more consistent transactor/transaction approach for all pension and insurance transactions. Four main topics are covered: (1) social security, (2) private pensions, (3) life insurance, and (4) casualty insurance. Each is considered in terms of the treatment of contributions, the treatment of benefits, and the handling of reserves and the income generated by them. The same sorts of problem arise in all four cases.

Notes: Production maximization, together with an appropriate distribution of income and wealth, can no longer be considered as the exclusive objective of socio-economic policies. Economic and social life is accompanied by numerous hardships, constraints and damages which demand to be minimized. Combining these dual aims is not easy as no single model has yet been set up taking into account all these inter-relations. However, one may try to reduce the uncertainty about the statistical material that could be required for decision-making in this new context.

Notes: For estimates of the wealth distribution Canada depends on household surveys taken at 6–7 year intervals. The latest data from this source refer to household balance sheets in the spring of 1977. A comparison with 1970 shows that there is little change in the composition of wealth held by households but that inequality of the wealth distribution has been somewhat reduced. Wealth data by age of family head is presented in order to describe more fully the wealth distribution and composition in Canada.Weaknesses in the data are discussed as well as the difficulties of making appropriate adjustments to the data at the micro record level. For policy evaluation and formulation purposes the lack of comprehensive estimates inclusive of pension wealth as well as the small sample size (12,700 usable records) have been perceived as greater obstacles to utilizing the data than the underestimate in aggregate assets and debts which affects more the higher than the middle and lower ranges of the wealth distribution.

Notes: The article refutes the contention that Brazil's development has not benefited the poor and that rapid growth has had a polarizing effect on the distribution of income. It uses the National Household Expenditure Survey of 1974–75 to try to quantify the extent of poverty and concludes that the incòme levels of the poor have been underestimated in the past. The evidence suggests also that occupational and regional variables are powerful determinants of income stratification. Wage rate statistics convey information about long-term trends in income. The article notes considerable increases in rural wages during the 1970s as well as wage improvements in the urban informal sector. Shifts in the structure of employment have probably been the most powerful cause of economic improvement in Brazil. The enormous absorption of rural-urban migrants occurred without a flooding of the lower income urban categories. Social indicators and statistics referring to ownership of household durable consumer goods corroborate income and labor market evidence to the effect that there has been considerable progress for the poor during the 1970s. The article reviews statistical evidence bearing on distribution. There is little doubt that the distribution of income in Brazil is very skewed. It is not possible, however, to come to conclusions about changes that might have occurred in the degree of inequality over time. Finally, the article includes data on the “distribution of education” and the “distribution of life expectancy” and notes improvement over time in both.This article takes advantage of the Brazilian population census of 1980 to bring up to date some of the statistical material that bears on the issues of poverty and income distribution. First, the article describes the overall context of Brazilian development since 1960. The second part analyzes the extent of poverty in the mid-1970s. The third part deals with trends in wages, employment and selected welfare indicators. The last section briefly summarizes the information relating to income distribution: what is the extent of skewedness and how has it evolved over time?