ALBERT

Notes: Unicapsula seriolae n. sp. forms long plasmodia within the striated muscle fibers of Seriola lalandi off eastern Australia. Its spores are composed of three valves, only one of which contains a developed polar capsule. Within the capsule, the filament makes 2 1/2–3 turns, and this criterion can be used to separate U. seriolae from the two other members of the genus. The flesh of infected fish disintegrates during slow cooking.

Notes: Twenty-nine (64.4%) of 45 reindeer, Rangifer tarandus, examined over a two-year period were infected with trypanosomes. Trypomastigotes and dividing epimastigotes were found in the blood of fawns, cows, and bulls. Morphometric analysis of bloodstream trypomastigotes from reindeer and comparison of these parasites with similar stages of trypanosomes from elk, mule deer, and white-tailed deer from the contiguous United States proved them conspecific; the trypanosomes from these members of the Cervidae are identified as Trypanosoma cervi Kingston & Morton, 1975. This is the first report of trypanosomes from reindeer. No pathogenic effects are known to be caused by these parasites.

Notes: We investigated the growth requirements of symbiont-free and symbiont lambda-bearing Paramecium octaurelia stock 299 for folic acid and biopterin in chemically defined culture medium. Symbiont-free P. octaurelia required both folic acid and biopterin for growth. In the absence of these substances growth of symbiont-free P. octaurelia failed after the first transfer, whereas symbiont lambda-bearing P. octaurelia could be maintained indefinitely in serial subculture. In the absence of folic acid and biopterin, sulfanil-amide inhibited growth of the symbiont lambda-beating protozoa. In the presence of folic acid and biopterin, the antiobiotic selectively inhibited growth of lambda symbionts but did not affect growth of the protozoa. In both cases, inhibition by sulfanilamide was reversed by addition of p-aminobenzoic acid to the medium. These results support our earlier finding that folic acid is required for growth of symbiont-free P. octaurelia 299 and that growth of the lambda-bearing strain without exogenous folate denoted synthesis of folic acid by the symbionts. In addition, it appears that the symbionts produce sufficient biopterin to meet the needs of the host protozoon for growth.

Notes: Book Reviewed in this article:Canning, Elizabeth U., ed. 1981. Parasitological Topics: a Presentation Volume to P. C. C. Garnham F.R.S. on the Occasion of His 80th Birthday 1981Krylov, M. V. 1981. Piroplazmidy. [Piroplasms.]Baker, J. R. 1982. The Biology of Parasitic ProtozoaBarriga, Omar O. 1981. The Immunology of Parasitic Infections: a Handbook for Physicians, Veterinarians, and BiologistsBeyer, T. V., Bezukladnikova, N. A., Galuzo, I. G., Konovalova, S. I. & Pak, S. M., eds. 1979. Toksoplasmidy. [The ToxoplasmidsGeltzer, Ya. G., Korganova, G. A., Mavlyanova, M. I. & Nikolyuk, V. I., eds. 1980. Pochvennye Prosteyshie. [The Soil Protozoa.] (ProtozoologiyaBeyer, T. V., Kazakova, I. I., Lakhonina, G. M., Roigas, E. M. & Teras, J. H., eds. 1981. Vzaimootnosheniya Prosteyshikh s Virusami. [The Interaction between Protozoa and Viruses.] (ProtozoologiyaOgimoto, Keiji & Imai, Soichi 1981 Allas of Rumen MicrobiologyLong, Peter L., ed. 1982. The Biology of the CoccidiaLloyd, David, Poole, Robert & Edwards, Steven W. 1982. The Cell Division Cycle: Temporal Organization and Control of Cellular Growth and ReproductionFrederick, J. F., ed. 1981. Origins and Evolution of Eukaryotic Intracellular Organelles. [Ann. N.Y. Acad. Sci.Hayat, M. A. 1981. Fixation for Electron MicroscopyBuetow, D. E., ed. 1982. The Biology of Euglena.Ogden, C. G. & Hedley, R. H. 1980. An Atlas of Freshwater Testate AmoebaeParker, S. P., ed. 1982. Synopsis and Classification of Living OrganismsMargulis, L. & Schwartz, K. V. 1982. Five Kingdoms: an Illustrated Guide to the Phyla of Life on EarthCairns, J., Jr., ed. 1982. Artificial SubstratesCurds, C. R. 1982. British and Other Freshwater Ciliated Protozoa

Notes: . Freeze-fracture techniques reveal differences in fine structure between the anterior three flagella of Tritrichomonas foetus and its recurrent flagellum. The anterior flagella have rosettes of 9–12 intramembranous particles on both the P and E faces. The recurrent flagellum lacks rosettes but has ribbon-like arrays of particles along the length of the flagellum, which may be involved in the flagellum's attachment to the cell body. This flagellum is attached to the membrane of the cell body along a distinct groove that contains few discernible particles. Some large intramembranous particles are visible on the P face of the cell body membrane at the point where the flagellum emerges from the cell body. The randomly distributed particles on the P and E faces of the plasma membrane have a particle density of 919/μm2 and 468/μm2 respectively, and there are areas on both faces that are devoid of particles. Freeze-fracture techniques also reveal numerous fenestrations in the membrane of the Golgi complex and about 24 pores per μm2 in the nuclear. membrane.

Notes: . Extraction of the ciliated protozoon Tetrahymena with nonionic detergents produces a surface-related cytoskeleton that consists of a basic lamina of whole-cell dimensions together with associated microtubule and microfilament systems, including all ciliary basal bodies. The organization of the isolated cytoskeleton has been studied using scanning electron microscopy, and several new features are described in the oral region. Here the ciliary basal bodies are arranged in a very stable and highly complex pattern. This pattern was found to be identical in the four species of Tetrahymena we examined. In addition, various microtubular bundles and two separate systems of filaments were observed in scanning electron micrographs of isolated oral skeletons. The appearance of the deep fiber bundle in preparations of this type suggests that it arises, at least in part, as an extension of the ribbed wall microtubules. On the basis of its distribution within the oral skeleton, one of the filament systems described is suggested to be a contractile system responsible for pinching off food vacuoles.

Notes: . Dehydrogenase activity with hydroxysteroids has been observed in Tetrahymena furgasoni (formerly T. pyriformis strain W), and the enzyme responsible has been isolated from this organism. The purified dehydrogenase is active with a variety of steroid alcohols at apparent Km values ranging from 0.2 to 4.0 mM. The C-3 hydroxyl of ring A of the steroid nucleus is the preferred position of oxidation. However, a variety of other secondary alcohols are also substrates, with apparent Km values for 2-butanol, 2-pentanol, and cyclohexanol of 880, 1000. and 150 mM, respectively. With both steroidal and nonsteroidal alcohols. NAD is the preferred co-substrate, although low activity with NADP is observed. Evidence is presented that the activity with secondary alcohols, whether steroidal or not, is the property of a single protein species.

Notes: . Domestic turkeys naturally infected with Leucocytozoon smithi were blinded by bilateral ocular enucleation, pinealectomized, sham-pinealectomized, pinealectomized plus enucleated, or maintained as controls. Groups of turkeys were acclimated to either light-dark periods of 14L:10D or “darkness” with intermittent periods (10–20 min) of red light at irregular hours approximately every three days as required for maintenance of turkeys. Peripheral gametocyte numbers of L. smithi in all groups were determined every 2 h over a 36 h period. Under 14L: 10D photoperiod, no observable difference in the pattern of gametocyte circadian rhythmicity between pinealectomized, enucleated, pinealectomized plus enucleated, and control turkeys was noted. Although mean parasitemias differed among groups, peak gametocyte numbers occurred between 1000 and 1800 h; how parasitemias occurred between 2000 and 0400 h. However, the phase of gametocyte rhythmicity in pinealectomized plus enucleated turkey hosts did exhibit a lag with reference to other hosts when examined by least squares fits of simple harmonics. Under conditions of “darkness” with intermittent, irregular periods of red light, L. smithi gametocyte numbers of individual turkeys, pinealectomized, sham-pinealectomized, or maintained as controls, exhibited a circadian periodicity though parasite cycles were out of phase with the natural photoperiod to which the turkeys previously had been exposed. A slight drift out of phase of L. smithi gametocyte periodicity occurred among turkeys in the sham-pinealectomized and the control groups while a considerably more prominent drift out of phase was seen among the parasite rhythmicity patterns of the pinealectomized birds. Data indicate that the pineal gland of the turkey did not directly mediate L. smithi gametocyte circadian periodicity, although an indirect involvement in regulating the timing of parasite rhythmicity is suggested.

Notes: . The surface of merozoites and sporozoites of Eimeria tenella was affected by incubation with E. tenella-immune chicken serum (ICS). Normal chicken serum (NCS) and heat-inactivated ICS had no effect on the pellicular surface of either developmental stage. Sporozoites formed surface bulges or swellings after 10 min of incubation with ICS, and by 15 min postincubation, the morphology of the sporozoites was distorted by a surface coating of fibrinous material. Merozoites exposed to ICS were similarly coated, but surface swelling was not as severe. The coating formed rapidly and was seen as early as 5 min postincubation. Sporozoites incubated with heat-inactivated ICS supplemented with normal chicken serum were coated with a fibrinous material and in some cases lysed. These data indicated that complement must be present for the surface interaction to occur.

Notes: . The fine structure of the trophozoite, encysting cells, and the cyst of Acanthamoeba astronyxis has been examined. In the trophic form a microtubule organizing center was associated with a well developed Golgi complex. During encystment the organelles of the amoeba changed considerably. The profiles of rough endoplasmic reticulum elongated and were often arranged in circles of multilayered concentric systems, enclosing mitochondria, the nucleus, or other inclusions. The mitochondria showed a tendency toward elongation and constriction. One or two nucleolus-like bodies appeared in the nucleus. Lipid droplets increased considerably in amount and were distributed individually or as aggregates. The mature cyst was star-shaped and surrounded by an almost circular exocyst and an endocyst that was closely apposed to the cell membrane. Both walls differed in their thickness and granulation. The exocyst was continuous over the entire cyst, while the endocyst was interrupted by gaps, ostioles. in the region of the rays. Within the ostioles was a bell-shaped structure, the operculum. The latter was composed of a granular material comparable in electron density to that of the endocyst.

Notes: Ambiphrya ameiuri is an ectocommensal peritrich that attaches to the gills of warm-water fishes and filters bacteria from the water. The ultrastructure of this protozoon, its attachment to the fish gills, and its effect on the gill tissue were investigated by scanning and transmission electron microscopy. The peritrich attached to the gills by fibers extending from the scopula. A microtubular array, apparently a barren kinetosome, was present in each lobular projection, but no scopular cilia were observed. At low densities Ambiphrya had no apparent harmful effects on the fish; however, at high densities respiration may be impeded. Ultrastructural studies indicate that this organism receives no nourishment from the host tissue.

Notes: Une méthode d'obtention et de maintien des Ciliés du rumen (genre Polyplastron) en culture axénique, est décrite. Elle comporte deux périodes d'incubation en anaérobiose avec différentes associations d'antibiotiques, séparées par un lavage et un renouvellement du milieu nutritif. Dans ces conditions. Polyplastron multivesiculatum est obtenu à l'état axénique et maintenu en survie pendant cinq jours.〈section xml:id="abs1-2"〉〈title type="main"〉ABSTRACTA method to obtain and keep rumen ciliates (genus Polyplastron) in an axenic condition is described. It consists of two incubating periods with different antibiotic mixtures, separated by washing and renewing of nutrient medium. Under these conditions, Polyplastron multivesiculatum is established in an axenic state and can survive thusly for five days.

Notes: Proteins of whole cell extracts of Naegleria fowleri, precipitated with acetone, have been resolved by two-dimensional polyacrylamide gel electrophoresis. Autoradiograms of the [35S]-methionine-labeled polypeptides were scanned and analyzed by a computer-assisted program in order to determine whether there were correlations between selected attributes of proteins (e.g., subunit size and charge). The majority of the polypeptides had molecular sizes within the range of 20–60 kilodaltons. The mean amount of polypeptide was less for those with molecular sizes between 20 and 45 kilodaltons than for those larger than 45 kilodaltons. The mean amount of polypeptide was greater in the isoelectric focusing range of pH 5–6 than in the range of pH 6–7. Polypeptides in the size range of 20–40 kilodaltons had a median isoelectric point of 6.1, whereas polypeptides in the size range of 40–80 kilodaltons had a median pI of 5.6. Our data indicated that molecular size and charge were not entirely independent variables, and that the composition of a polypeptide might have an important influence on its steady state level in N. fowleri.

Notes: During a survey of the coccidian parasites of reptiles from Iowa, three specimens of Crotalus horridus L., the Timber Rattlesnake, and one of Sistrurus catenatus (Rafinesque), the Massasauga Rattlesnake, were found to be passing oocysts of a Caryospora, here described as C. bigenetica n. sp. Since these snakes (family Crotalidae) are known to subsist mainly on small mammals, oocysts from one of the Timber Rattlesnakes were fed to laboratory white mice (Mus musculus L.) to determine if mammals might be involved as alternate hosts in the life cycle. At necropsy, tissues of the tongue and dermis of the mice revealed a sequence of stages which included mature male and female gamonts, fully sporulated sporocysts, “excysted” sporozoites, and “resting” sporozoites that lay individually in solitary, cyst-like host cells termed “caryocysts.” A coccidia-free Massasauga that was fed an infected mouse, at a time when caryocysts in the mouse would have been present, later passed oocysts similar to those of the original inoculum. These results, along with the discovery of endogenous stages (asexual and sexual) in the intestine of the Timber Rattlesnake and the experimentally infected Massasauga, suggest that this parasite has a heteroxenous life cycle pattern, with sexual stages occurring both in the ophidian and the mammalian hosts.

Notes: Ciliophrys marina is a small marine helioflagellate, with a central nucleus, which is capable of reversibly transforming from a rapidly swimming flagellate cell with no axopodia to the structure of a heliozoan with a flagellum that beats only a few times a minute. When in the flagellate form, the flagellum acts as a tractellum due to the tubular mastigonemes found along its length. When the rapidly swimming flagellate strikes a piece of debris, the flagellum goes through a very characteristic shock-induced avoidance reaction. Similarly, when a mechanical shock is delivered to the cell in its heliozoan form, the axopodia are contracted in less than 20 msec. Both reactions are inhibited in low calcium seawater. Transformation from the heliozoan to the flagellate form is accomplished by slow retraction and absorbance of the axopodia and activation of the flagellum. Ultrastructurally, each axopodium is found to contain three microtubules which attach to the outer nuclear membrane of the central nucleus at sites that this study characterizes by electron microscopy of thin sections and freeze fracture preparations. The mitochondria have tubular cristae, each containing an intracristal filament. Finally, a taxonomic review of the helioflagellates is presented, and it is suggested that C. marina is derived from the chrysomonads. An argument is also made for classifying C. marina with the heliozoan order Actinophryida, as a recently published classification of the protozoa does.

Notes: Laboratory-reared Fundulus grandis and F. heteroclitus were experimentally infected with Eimeria funduli by being fed Palaemonetes pugio (grass shrimp) collected from endemic areas. Histological sections were made of heart, liver, hepatopancreas, spleen, gall bladder, kidney, intestine, peri-intestinal fat, reproductive organs, and brain from F. grandis sacrificed at 1, 2, 6, 12, 18, and 24 h and from F. heteroclitus at 5, 6, 9, 14, 19, 24, 29, 34, 39, and 44 days after consuming naturally infected shrimp. We first found merogonous stages at day 9 postinfection (p.i.). No developmental stages of the parasite could be positively identified in the tissues of experimentally infected fish prior to day 9 p.i. Mature meronts were found 14 days p.i. The majority contained 8–16 (mean, 13) merozoites, but a few meronts had 18–26 (22) merozoites. Gamonts first appeared on day 14, were mature by day 19, and fertilization was completed by day 24 p.i. After sporoblast formation, sporopodia appeared during sporocyst wall formation, between days 24 and 29 p.i. Sporozoite formation was completed by day 44 p.i. in most sporocysts. Most endogenous stages occurred in hepatocytes; however, pancreatic and spleen cells were sometimes infected with gamonts.

Notes: A recent isolate of Eimeria praecox, strain G, was obtained from Georgia and purified. Studies of the life history, pathogenicity, and cross-immunity of the isolate were conducted to verify its identity. In inoculated three-week-old chickens, the occurrence of merogony and gametogony was limited to the superficial epithelium of the upper intestine. Oocysts, 23 × 19.5 äm, with a shape index of 1.17 were first observed 83 h after inoculation. Mortality and morbidity were not observed in any of the experimental birds. However, there was a positive correlation between dose of oocysts, reduced weight gain, and the incidence of exudative diathesis. These studies showed that E. praecox depresses weight gains in chickens and may be of economic importance. Although complete immunity to avian coccidiosis is believed to be species specific, chickens immune to E. praecox (G) or E. acervulina had a degree of cross-immunity to a heterologous challenge. Electrophoretic analysis of glucose phosphate isomerase and lactate dehydrogenase prepared from the European strain of E. praecox and E. praecox (G) showed no differences, confirming the identity of the isolate as E. praecox.

Notes: The antiviral agent phosphonoacetic acid inhibits growth of Tetrahymena thermophila at concentrations comparable to those inhibiting growth of other eukaryotic cells, with 50% inhibition at 0.5 mM phosphonoacetic acid. The compound is cytotoxk to Tetrahymena at concentrations greater than 2.0 mM. When a culture of Tetrahymena the growth of which was totally inhibited by 2.0 mM phosphonoacetic acid was diluted with fresh medium, growth resumed in an exponential, rather than synchronous, fashion. [2–14C]phosphonoacetic acid is not metabolized by Tetrahymena.

Notes: Agglutinins were not detected in sera from mice given one, two, or three intranasal (i.n.) inoculations or a single intravenous (i.v.) inoculation of trophozoites of Naegleria fowleri. However, agglutinins were produced following second and third i.v. inoculations. Serum immunoglobulin levels increased in both i.n.- and i.v.-inoculated mice. IgG and IgM increased substantially more for i.v.-inoculated mice. IgA levels increased more consistently for i.n.-inoculated mice.

Notes: The sensitivity and specificity of the indirect fluorescent antibody (IFA) test for the detection of serum antibodies were examined in mice that were infected with Eimeria falciformis, E. ferrisi, E. papillata, or E. vermiformis. For the study of each species, five groups of mice were given graded inoculation doses of 10, 102, 103, 104, or 105 sporulated oocysts in a primary infection. The sixth group was infected with three sequential doses of 1.5 times 103, 1.5 times 104, and 1.5 times 105 sporulated oocysts per mouse at two- to three-week intervals. All groups of infected mice developed serum antibodies. Sera were titrated by the IFA test with purified sporozoites. Strong fluorescence and high IFA titers were observed with homologous reactions mainly with the sera from mice infected with the higher inoculation dose levels in primary infections and from those given three sequential inoculation doses. Immunological cross reaction among the four species of Eimeria occurred at dilutions of 1:10 to 1:160. Very weak or no fluorescence of free sporozoites was observed with sera from noninfected mice, and there was no fluorescence of sporozoites contained in intact sporocysts.

Notes: . Allantosoma intestinalis, a suctorian ciliate isolated from the intestine of the horse, was studied utilizing light and electron optical methods. These small sausage-shaped organisms have a varying number of tentacles (between one and 12) located at each extremity of the body. The microtubular axoneme of each tentacle in cross-section consists of two files of microtubules arranged in a daisy-like configuration. Haptocysts occur in the tentacle shaft, abutted to the plasma membrane of the knob of the tentacle, and in the cell body. The haptocysts are bottle-shaped, with prominent annular striations around their midportion. The cell is covered by three membranes, an outer plasma membrane, an outer alveolar, and an inner alveolar membrane. A thin epiplasmic layer is found beneath the inner alveolar membrane, and a single row of microtubules underlies the epiplasm. The subpellicular microtubules are arranged parallel to each other forming a corset around the cell along the long axis: such a system is not characteristic of suctorians. A field of diminutive kinetosomes (each 180 nm long, max. of 15 per field), lacking cilia, was found below the cortex. The function of these prokinetosomes is unknown. A ciliated swarmer has not been observed, only the nonciliated adult. The characteristics of Allantosoma are compared with those of other suctorian genera.

Notes: . Temperature shifts have been used to block critical points in the conjugation sequence of Paramecium tetraurelia. Increasing temperatures above 27°C reduced ciliary agglutination, pair formation, and nuclear exchange; a complete inhibition of these stages occurred at 37°C. Temperatures below 19°C had no effect on ciliary agglutination or nuclear exchange but completely inhibited pair formation. The bases for the cells’ inability to form pairs at 19°C and 37°C were sought. Cells placed below 19°C were unable to deciliate or fuse membranes in the holdfast region; at 37°C, membrane fusion in both the holdfast and paroral regions was prevented. Time course studies on cross-fertilization reveal that temperatures 35°C block all stages of the process up to the actual exchange of pronuclei. After the exchange has begun, the process continues despite the elevated temperature. Temperature shifts are discussed as a means of conditionally blocking critical points in the developmental program of conjugation.

Notes: . [14C]chimyl and [3H]batyl alcohols were added to Crithidia fasciculata cultures during the mid-log phase of cell growth, and the lipid extracts of the cells were analyzed for degradation products. C. fasciculata cells were able to take up exogenous glyceryl ethers, and in amounts as high as the endogenous lipid content. The glyceryl ether taken up by the cells was incorporated into lipids either prior to the ether bond cleavage or after degradation to fatty acid. The extent of degradation and the degree of incorporation of degradation products into cellular lipid were higher for chimyl than for batyl alcohol. Batyl alcohol was not metabolized efficiently, leading to the formation of large intracellular pools of free substrate. One product of glyceryl ether degradation was identified as alkyl-dihydroxy acetone, and was detected inside and outside of the cells. The data strongly suggest that this product is the first stable intermediate in the degradation process and indicate that the extracellular formation of alkyl-dihydroxy acetone is due to the action of exocnzyme; ecteted by the cells. The constant detection of alk I cnyl glycerol among the degradation products indicates the existence of a second mechantsm in C. fasciculata for converting the alkyl-to alkenyl-glycerol.

Notes: . Sick budgerigars from a local aviary were found to be infected with Giardia. The trophozoites were of the Giardia duodenalis type as defined by Filice with elongate median bodies pointed on one or both ends and more or less perpendicular to the long axis of the body. Using three fixation-staining methods, and material from three birds, the length ranged from 10 to 18 μm and the width from 4.5 to 11 μm with a mean length to width ratio of 2. Attempts to culture the trophozoites in vitro from intestinal scrapings were unsuccessful. Also attempts to transmit the infection by fecal cysts to canaries and mice failed. It is proposed that the budgerigar form be called Giardia duodenalis, race psittaci.

Notes: Three species of Pseudocohnilembus were examined with respect to infraciliature and the silverline system. The freshwater species P. putrinus and P. pusillus exhibited no differences in general organization of the argyrophilic structures when compared with the marine P. marinus. A review of the Pseudocohnilembus species that have been described on the basis of silver preparations shows that at present four species have been well characterized: P. pusillus (Quennerstedt, 1869) nov. comb., P. putrinus (Kahl, 1928) nov. comb., P. hargisi Evans & Thompson, 1964, and P. marinus Thompson, 1966, P. persalinus Evans & Thompson, 1964 and P. longiseta Evans & Thompson, 1964 are regarded as identical with the older known P. pusillus, because with respect to morphology and argyrophilic structures they are within the range of variability of that species; and their names thus fall as synonyms of P. pusillus.

Notes: The structure of micronemata arising from the surface of the bloodstream form of Trypanosoma gambiense was studied by electron microscopy. In order to produce micronemata, trypanosomes were incubated in either 1) phosphate buffered saline supplemented with glucose (PBSG), 2) immune mouse serum or 3) PBSG after passage through a DEAE-cellulose column. Electron microscopic examination of the parasite revealed the presence of thread-like micronemata arising from the anterior end and from the flagellar pocket regardless of the incubation conditions. Negative staining revealed a distinct peripheral fringe layer with nodular protrusions covering the entire surface of the micronema. The distribution and number of intramembrane particles (IMP) on the P and E faces of the micronema were similar to those of the flagellum of T. gambiense, indicating a close relationship between the membrane structure of the micronema and the flagellum. Micronemata became fragmented and adhered to each other after incubation of the parasite in the media for 12 h. Since micronemata tend to have the characteristics of adhesiveness and fragmentation, fragments of these structures might adhere to various host organs. Dispersal of potential antigenic material might be responsible, in part, for the induction of the host immune response.

Notes: The motion of Paramecium caudatum has been investigated at various temperatures by measuring the transient behavior of spatial distribution in the diffusion process of organisms that, by electric stimulus, are initially gathered at a single place in the glass culture cell. The spatial distribution through the course of diffusion has a nearly Gaussian profile. Dispersion was obtained at 1 sec intervals and increased linearly with time. The time dependence of the dispersion gave a diffusion coefficient for the random motion of the organisms. The results show that the diffusion coefficient has a maximum at the temperature at which the paramecia were cultivated.

Notes: The structure of both the host and parasite membranes during stages in the asexual development of Plasmodium chabaudi in mouse red blood cells is examined by transmission electron microscopy of thin sections and freeze-fracture preparations. The erythrocyte's plasma membrane, the membrane of the parasitophorous vacuole, and the plasma membrane of the parasite exhibit different structural properties in terms of membrane width and the frequency and diameter of the typical intramembrane-particles (IMP) populating the membrane's fracture faces. The difference between the parasitophorous vacuolar membrane and host cell's plasma membrane is remarkable because the vacuolar membrane is formed from an invagination of the erythrocyte's plasma membrane. The vacuolar membrane has significantly reduced frequencies and diameters of IMP's on both faces and reveals a marked temperature response manifesting itself as large IMP-devoid domains emerging on both faces on chilling to 4°C. In contrast, cooling induces only some very small IMP-devoid patches on both faces of the host plasma membrane. Neither of these membranes changes significantly as parasite development progresses. In contrast, the parasite's plasma membrane shows local alterations during its development, forming compaction domains with the nuclear envelope in ca. 30% of the ring-stages and trophozoites. These compaction domains disappear in late uninuclear trophozoites and schizonts. Furthermore, the plasma membrane of the host cell, the vacuolar membrane, and the parasite's plasma membrane do not respond to externally applied Ca2+, and their temperature-response remains unaltered during the infection cycle. Thus, modification of these three membranes as a consequence of invasion and development of the parasites, as recently found in the primate malaria caused by P. knowlesi, can be detected neither directly nor indirectly via temperature- and/or Ca2+-response in the rodent malaria caused by P. chabaudi.

Notes: A system of prescreens and screen has been developed to select chelators as potential drugs against Trypanosoma brucei brucei EATRO 110. The chelators tested were nearly all commercially available, low molecular, and having moderate to high affinity for Fe(III). We prescreened 70 compounds showing heme-sparing or inhibitory activity in a Crithidia fasciculata growth system having excess Fe and minimal hemin. Of these, 45 were highly trypanocidal for suspensions of bloodstream T. b. brucei; criteria of activity here were immobilization, lysis, and loss of infectivity. Eighteen of the chelators highly active in the suspension prescreen were tried in T. b. brucei-infected mice. Thirteen of these chelators were curative in mice with 24-h infections, that is, they allowed survival 〉30 days beyond the untreated controls. 3,4-Dihydroxycinnamic acid (caffeic acid). 2,9-dimethyl-1, 10 phenanthroline (neocuproine), and 2-pyridinecarboxaldehyde-2-pyridyl-hydrazone cured five out of five mice after an i.v. dose of 100 mg/kg. Salicylaldehyde thiosemicarbazone cured five out of five mice at an i.p. dose of 500 mg/kg. Lesser activity was shown by several other chelators.

Notes: The size and fatty acid composition of Tetrahymena pyriformis W cells were influenced by the provision of a nutritional supplement of ergosterol, cholesterol, or tetrahymanol, but not of 20-isocholesterol. Ergosterol and cholesterol addition led to a reduction in cellular volume, an increase in glycerophospholipid saturated fatty acid content, and an increase in palmitoleic acid and its metabolic products when compared to unsupplemented controls. Tetrahymanol supplementation resulted in an increase in cellular volume, a decrease in saturated fatty acid content, and a reduction in palmitoleic acid and derivatives. 20-Isocholesterol was accumulated by the cells; however, this compound had no effect on any of the parameters followed in this investigation and had only a small depressant effect on tetrahymanol biosynthesis. Ergosterol and cholesterol had the same impact on the ciliates, even though the ergosterol-supplemented cells contained approximately three times as much free sterol as did cholesterol-grown cells. The amount of the free cholesterol and metabolic products in supplemented cultures was similar to the amount of tetrahymanol present in control cultures. This observation suggests that the cells recognize qualitative differences among the various polycyclic alcohols rather than responding to the amount of sterol present. Increased cellular levels of tetrahymanol led to a response unlike that of the true sterols, which again suggests that the high degree of specificity depends on the structure of the added polycyclic alcohol. The changes in fatty acid composition may be required to maintain proper interaction of the polar lipids and the polycyclic alcohols to give an appropriate degree of membrane fluidity.

Notes: An unknown, ninhydrin-positive substance detected on paper chromatograms of the endogenous metabolites of mixed rumen ciliate protozoa was isolated and purified by column chromatography with ‘Dowex’ 50-X8 resin and identified as 2-aminobutanoic acid (α-amino-n-butyric acid) on the basis of elementary analysis, mass spectrometry, paper chromatography, infrared spectrometry, and melting point.

Notes: Book reviews in this article: Dillon, Lawrence S. 1981. Ultrastructure, Macromolecules and Evolution Schwemmler, Werner & Schenk, Hainfried E. A., eds. 1980. Endocytobiology: Endosymbiosis and Cell Biology, a Synthesis of Recent Research Krylov, M. V. & Starobogatov, Y. I., eds. 1980. Principles of the Construction of the Macrosystem of the Unicellular Animals Palmer, W. J., ed. 1981. Rapid & Automated Methods in Microbiology & Immunology: A Bibliography, 1976–1980 de Harven, E. & Nemanic, M. K., organizers. 1981. Cell Surface Labeling Inoki, Shozo, ed. 1981. Atlas of Protozoa Czapik, Anna 1980. Pdostawy Protozoologii. [Introduction to Protozoology.] Levine, Norman D. & Ivens, Virginia 1981. The Coccidian Parasites (Protozoa, Apicomplexa) of Carnivores Page, Frederick C. 1981. The Culture and Use of Free-Living Protozoa in Teaching

Notes: . Conjugating cells of Euplotes vannus (syngens Naples and Barcarès) were investigated for Con A-binding sites by means of fluorescence microscopy. Cells fixed with 0.4% paraformaldehyde and incubated with 15 μg/ml FITC-Con A showed a distinct region of strong fluorescence, the size, shape and localization of which characteristically changed during the course of conjugation, first appearing at courtship stage (cells contact without forming pairs) and vanishing soon after the migration pronuclei have been exchanged, but before cells have separated. Con A binding and conjugation were blocked by cyclohexamide and α-galactosidase. Con A-binding was also inhibited by α-mannosidase, α-glucosidase and β-galactosidase without affecting conjugation except a delay of pair formation. The results suggest an involvement of newly formed or translocated glycoconjugates in cell pairing during conjugation.

Notes: . The development of Sarcocystis cruzi was studied in an 11-day-old calf killed seven days postinoculation with 5 × 108 sporocysts from feces of coyotes. Uninucleate zoites were found in arteries of mesenteric lymph nodes but not in other organs. Zoites measured 4.9 × 3.0 (3.5–7.0 × 2.1–3.5) μm. Of the 36 zoites studied, 31 were in endothelial cells, four were in macrophages in the lumen of arteries, and one was free in the lumen of an artery. Infected endothelial cells were two to three times larger than uninfected cells. Zoites appeared structurally similar to sporozoites. The occurrence of zoites in macrophages suggests that sporozoites of Sarcocystis might use such cells to reach the site of their first merogony.

Notes: . The enzyme that catalyzes the critical conversion of the proposed reductive thymidine catabolic end product, P-aminoisobutyric acid, to the initial anabolic reutilization substrate, probably methylmalonic semialdehyde, was investigated to un- ambiguously substantiate the operation of a reductive pyrimidine catabolic and reutilization pathway in Tetrahymena pyriformis strain GL. Although most of the studies on the further metabolism of P-aminoisobutyric acid in other organisms suggested transamination of p-aminoisobutyric acid to methylmalonic semialdehyde followed by its further oxidation to methylmalonic acid, such a transaminating system could not be demonstrated. By means of a sensitive fluorometric assay system, however, a low, but significant amount of P-aminoisobutyric acid oxidase activity was detected. This enzymatic activity exhibited the following characteristics in homogenates: good activity in alkaline 0.2 M Tris-HCI buffer with a rather broad pH optimum ranging from 7.8 to 9.0; optimum activity at a temperature of 37°C; stimulation on the addition of exogenous FAD; inhibition on the addition of divalent cations, EDTA, or PCMB; little stimulation on the addition of detergents; and no increase in activity on repeated freezing and thawing. In addition, crude preparations of this oxidase were found to be relatively stable when stored up to one week either refrigerated or frozen, to have a specific activity of 2.8 nmoles/min/mg of protein, and to have a K, of 3.6 × 10− M for d,l-β-aminoisobutyric acid. Whether this high Km, is physiologically significant or not, however, will have to await further investigation. Preliminary (NH4)2SO4 fractionation and affinity chromatography studies also indicated that this enzyme appears to be a unique and specific oxidase whose activity is separable from other marker enzymes, including other oxidases.

Notes: . Phosphatase activity in Trypanosoma rhodesiense has been examined histochemically by light and electron microscopy and by enzymatic assay in homogenate fractions. Using a method with lead as capture ion, acid phosphatase was found in lysosome-like vesicles and in the flagellar pocket. No alkaline adenosine triphosphatase (ATPase) was detectable by this method. Direct assay of p-nitrophenylphosphatase activity in homogenate fractions showed that acid phosphatase activity was strongly membrane-bound, but that activity at pH 9 was minimal in both soluble and particulate fractions. “Endogenous” ATPase activity was localized specifically and reproducibly in the mitochondrial membranes and under the plasma membrane of the flagellum. This nonenzymic reaction product could not be eradicated by glycerol extraction or glucose depletion. Unlike the membrane staining, which was manifest only after lead treatment, heat-resistant electron-dense material was found in the matrix of lysosomal vesicles in trypanosomes fixed in glutaraldehyde only and not subjected to further treatment with heavy metal reagents. X-ray emission analysis showed the presence of calcium and phosphorus, indicating that the matrix might have a phosphate storage function.

Notes: The longitudinal flagellum of Ceratium tripos moves in two dissimilar ways: undulation and retraction. The undulatory wave is planar and has a wavelength of 74.3 ± 9.6 μm and an amplitude of 14.2 ± 2.3 μm in sea water. The beat frequency is 30 Hz at 20°C, pH 8.0. The retractile motion is unique to Ceratium and is triggered by mechanical stimulation on the cell body, especially at the tip of the apical horn. When it retracts, the longitudinal flagellum folds every 4–5 μm along the flagellum. Cinematographic study showed that the flagellum folded from tip to base and was finally installed into the sulcus, a groove on the ventral side of the cell. This motion is completed in sea water within 28 msec. The retracted flagellum then re-extends and restores the undulation within a few seconds. The flagellum unfolds in the proximal portion first, then the distal, and finally the middle portion. Fixation always triggers the retraction. Scanning electron microscopy showed that the flagellum is folded and secondarily twisted in a helix. A new fiber in addition to the flagellar axoneme was found in the retracted flagellum by phase microscopy. This fiber (R-fiber) seems to contract during the retraction to fold the flagellum.

Notes: Phagocytosis of culture forms of Trypanosoma cruzi was assayed by a radioisotopic method. Purified polymorphonuclear leukocytes (PMN) were mixed with 3H-uridine-labeled T. cruzi epimastigotes in the presence or absence of anti-T. cruzi antibodies. The reaction was stopped by adding N-ethyl-maleimide, and noningested parasites were lysed by complement. The percentage of radioactivity incorporated into the PMN pellet was recorded. The phagocytosis reaction was rapid, yielding maximum incorporation at 30 min at which point the radioactivity associated with the PMN cells decreased through release of the isotope to the supernatant. The degree of incorporation of radio-labeled parasites was a function of the effector/target cell ratio and the antibody concentration. The method is suitable for the quantitative determination of phagocytosis of T. cruzi by normal PMN.

Notes: The following species of the gregarine genus Lankesteria were found in a study of ascidians from Monterey Bay, on the central California coast of the Pacific Ocean: L. abbotti n. sp. in Clavelina huntsmani, L. aplidii n. sp. in Aplidium solidum, L. ascidiae in Ciona intestinalis, L. diaphanis n. sp. in Archidistoma diaphanes, L. euherdmaniae n. sp. in Euherdmania claviformis, L. montereyensis n. sp. in Archidistoma molle, L. pescaderoensis n. sp. in Ritterella rubra, L. pittendrighi n. sp. in Ascidia ceratodes, L. psammii n. sp. in Archidistoma psammion, L. ritterellae n. sp. in Ritterella pulchra, L. ritterii n. sp. in Archidistoma ritteri, L. synoici n. sp. in Synoicum parfustis, and Lankesteria sp. in Botrylloides sp. No gregarines were seen in the following ascidians: Aplidium californicum, A. propinquum, Botryllus tuberatus, Diplosoma macdonaldi, Perophora annectens, and Polyclinum planum.

Notes: The effect of holothurin (a marine biotoxin) on the resistance of mice to Trypanosoma musculi was measured by studying changes in the parasite population in vivo. Swiss Webster (SW), Beige (BG), and Black (BL) mice treated with holothurin prior to and simultaneously with infection of trypanosomes had lower parasitemias than controls. Higher levels of parasitemia were observed in mice treated after infection with trypanosomes. The timing of administration of holothurin appeared to be an important factor in the observed effect. The minor variations in the parasitemia seemed to be related to the mouse strain.

Notes: The structure of the cyst wall of the heliozoon Echinosphaerium nucleofilum has been investigated using light microscopy, scanning and transmission electron microscopy, and X-ray microanalysis. The cyst wall is a composite structure of seven or eight layers. These are: an enveloping gelatinous layer; a layer of siliceous spheroidal bodies; an electron-dense supporting membrane; a broad electron-lucent zone; an electron-dense layer; a layer of helicoidally packed material; and one or two layers with a granular appearance lying next to the plasma membrane of the encysted organism. The structure of the cyst wall closely resembles that of Actinophrys sol, confirming the close relationship of these actinophryid heliozoa while emphasizing their distinctiveness from other amoeboid protista.

Notes: Morphogenesis of cell division was investigated in Diophrys scutum, D. oligothrix, and D. appendiculata utilizing both light microscopy of living and stained specimens and SEM of preserved specimens. The cortical morphogenetic pattern of Diophrys is similar to that of other members of the family Euplotidae. The opisthe oral primordium, which develops in a subsurface pouch, forms posterior to the parental buccal cavity. The proter inherits the parental adoral zone of membranelles (AZM) apparently unchanged. The endoral membrane forms to the right of the posterior end of the AZM in the proter, in association with the developing AZM in the opisthe. The paroral cirrus and membrane develop from a single streak that first appears along the right edge of the buccal cavity in the proter to the right of the developing buccal structures of the opisthe. Frontal and transverse cirri develop in both proter and opisthe from five separate cirral primordia that form to the right of the buccal cavity. Left marginal cirri do not develop in association with the corresponding parental structures. Kinetosomes formed within the opisthe oral primordium, or kinetosomes that were part of any parental ciliary structure, do not appear to become part of any developing paroral structures, frontal, transverse, or left marginal cirri. Speciation within the genus Diophrys and evolution of the family Euplotidae as they relate to the morphogenesis of cortical structure are discussed.

Notes: Autecology (cellular organelles and secretions, encystment and dispersal abilities), environmental conditions (physiological tolerances and interaction with other organisms), and evolutionary history contribute to protist biogeography, which manifests ecological and historical aspects. Ecological biogeography is seen in the influence of geochemistry on the distribution of fresh-water phytoflagellates and algae, and of moisture and vegetation type on soil-litter protists. A temporal feature is often present because many protists encyst and respond only to certain ranges of temperature and organic content. Historical biogeography has occurred by radiative host evolution on symbiotic protozoa (e.g., termite flagellates and rumen ciliates), and by the isolating effects of water currents, temperature, and density gradients on oceanic protists (coccoliths, dinoflagellates, foraminifera, radiolaria, and tintinnines). These two aspects combine in protists living on animal surfaces. Humans affect protist biogeography by increasing parasite ranges through human migrations and by water pollution. They can diminish these situations by disease control and exploiting appropriate ciliates in sewage disposal. Many free-living protozoa appear to be cosmopolitan, but mating types and isoenzyme studies suggest that speciation with its geographic connotations may be more widespread than presently appreciated.

Notes: Available evidence indicates that many of the antiprotozoal drugs currently in use significantly modify the immune response of the host. The effect depends on both the drug and the host. Some drugs enhance the immune response, some are immuno-suppressants, and others enhance some types of immune mechanisms while suppressing others. Future efforts in the development of antiprotozoal drugs should consider their effects on both the parasite and the immune response of the host. Also in the chemotherapy of protozoal infections consideration should be given to the combined usage of immunoenhancing agents and antiprotozoal drugs.

Notes: A survey of protozoa polluting bottled mineral water in Mexico was carried out using samples obtained from the three best-selling brands of bottled mineral water in the country. The organisms were concentrated through filtration procedures and subsequently cultured in sterile media. The cultures were observed over four weeks, with identification to the level of genus and species. Most commonly found were the amoebae Naegleria gruberi, Acanthamoeba astronyxis, and Vahlkampfia vahlkampfi (trophic as well as cystic stages) plus one flagellate, Bodomorpha minima. No ciliates were detected. The public health importance of the findings is obvious, since some strains of Naegleria and Acanthamoeba have the potential to cause human disease that may lead to death.

Notes: Nineteen clones of Trypanosoma cruzi were obtained as single-cell isolates from Triatoma infestans. Ten of the clones were isolates from a patient with chronic Chagas' disease; nine clones were isolates from a dog infected with T. cruzi strain CA-I isolated originally from a chronic chagasic patient. The growth kinetics and peak modal Coulter volume of these clones were characterized. Significant inter- and intra-group differences between growth rates and peak modal volumes were found. These data indicate that subpopulations and, consequently, genetic heterogeneity of T. cruzi exist in chronic chagasic patients. All of the clones infected vertebrate cells in vitro.

Notes: The ox-coyote cycle of Sarcocystis cruzi was studied by killing 38 calves between 4 and 153 days postinoculation (DPI) with 55 × 103-5 × 108 sporocysts from the intestines of coyotes. At 4 DPI, a zoite was found within the lumen of a mesenteric lymph node artery. At 7 DPI, zoites were found in mononuclear cells and in endothelial cells in mesenteric arteries. First generation meronts (41.0 × 17.5 μm in diameter) occurred 7–26 DPI in mesenteric lymph nodes. At 19–46 DPI, second generation meronts occurred in kidneys, muscles, and other tissues: renal meronts were 19.6 × 11.0 μm, and intramuscular meronts were 25.0 × 11.1 μm. Merozoites were found in the peripheral blood 17 DPI and later at 24–46 DPI. They divided by endodyogeny in mononuclear cells. Sarcocysts were seen first in the heart at 45 DPI and contained one or two metrocytes. At 55 DPI, sarcocysts containing only metrocytes were found in striated muscles, heart, and in smooth muscles of the urinary bladder, rumen, omasum, abomasum, and small intestine. At 67, 87, 112, and 153 DPI, sarcocysts were found only in striated muscles and in the heart. At 67 DPI, sarcocysts were up to 360 μm long. They contained only metrocytes and were not infective to the dog. At 86 DPI, sarcocysts contained mostly bradyzoites, a few metrocytes, and were infective to a coyote. The thin-walled sarcocysts grew to a maximum length of 800 μm and contained bradyzoites that were 10.9 × 3.0 μm. At 90 DPI, two mature sarcocysts were found in 2 of 73 sections of brain and spinal cord; hundreds of sarcocysts were present in sections of tongue and heart of this calf. Gametogony occurred in the small intestine of the coyote. Macro-and microgamonts were found in goblet cells of the small intestines of coyotes 6 h after the ingestion of infected meat. Microgamonts were few and contained 3–11 slender gametes. Oocysts were seen at 12 h and sporulation was completed 9 DPI. The prepatent period in the coyote was 8 days. The ox-coyote cycle is compared with ox-dog cycle.

Notes: The structure of the oral apparatus in the carnivorous macrostomal form of Tetrahymena vorax has been investigated using serial thin sections and preparations of isolated oral apparatuses. The cilia of the oral apparatus are organized into an undulating membrane that borders the right and part of the posterior margin of the buccal cavity and three membranelles that project from plateaus on the anterior surface. Each membranelle consists of one short row and two longer rows of hexagonally packed kinetosomes. The organization of the microtubules of the oral ribs is identical to that in the T. vorax microstomal cell type. However, the first oral rib originates near the first kinetosome at the anterior end of the undulating membrane. The fine filamentous reticulum that underlies part of the oral ribs in the macrostomal cell type is not striated, unlike the reticulum in the microstomal form. A band of filaments similar to the fine filamentous reticulum extends around the anterior margin of the large cytostomal opening that occupies most of the posterior part of the oral cavity. The single row of microtubules along the left side of the oral cavity and cytostome also has filaments associated with it. A major difference between the microstomal and macrostomal forms in the structure of the oral apparatus is in the oral connectives. The macrostomal cell type contains only a single cross-connective that joins the three membranelles and the anterior portion of the undulating membrane. The posterior or peripheral connective between the posterior ends of membranelles one and two and the posterior end of the undulating membrane is absent.

Notes: . Studies of the bristle (dorsal) cilia of Euplotes minuta. E. aediculatus, and Stylonychia mytilus by light and electron microscopy indicate that these cilia do not beat metachronously in any of the species. The bristle cilia in Stylonychia may beat actively, but those in Euplotes stand erect or are bent in different directions with the flow of water. The duration and degree of bending appear correlated with the duration and velocity of the water current. The fine structure of the bristle complex is similar in both Euplotes species and like other reports of Euplotes in the literature. The complex consists of paired kinetosomes, the anterior bearing a short cilium containing four to six rows of fibrous balls (lasiosomes) oriented along the anterior surface of the axoneme, the posterior lacking a cilium but with a small cap. Microtubular ribbons are associated with the paired kinetosomes, and a collar with a pronounced alveolar ring underneath the pellicular membrane tightly surrounds the cilium at the opening of the bristle pit. The bristle complex in S. mytilus differs from that of Euplotes and other hypotrichs in that it has a single kinetosome in interphase cells and, attached to the kinetosome, a prominent fibrous structure (parakinetosomal body). Microtubules are attached to the parakinetosomal body. As in Euplotes, the bristle unit is surrounded by mucocyst-like organelles (ampules). Observations of behavior and fine structure suggest that the dorsal bristles may be sensory, perhaps responding to stimuli from water currents, although other functions are possible, too.

Notes: . The sequence of formation and ciliation of basal bodies and the subsequent organization of compound ciliary structures of the oral apparatus of Tetrahymena thermophila was reanalyzed with the aid of scanning electron microscopy of cells in which the epiplasmic layer was exposed, as well as by light microscopy of protargol-impregnated specimens. This combination of methods allowed the delineation of numerous steps in the patterning of the oral ciliature, some of which have received little or no previous attention. Highlights include: the initial formation of “strings” of nonciliated new basal bodies in juxtaposition to relatively few basal bodies of the stomatogenic kinety; generation of basal body pairs, roughly oriented along the anteroposterior axis of the cell, that later align side-by-side to assemble promembranelles; condensation and reorientation of promembranelles simultaneous with addition of a third row of basal bodies anterior to the original two rows; production of a very short fourth row of basal bodies at the anterior right end of each developing membranelle; generation of the outer basal body row of the undulating membrane (UM) after alignment of the inner row, with transient ciliation of the inner row preceding permanent ciliation of the outer row; limited basal body resorption at the ends of membranelles; and sculpturing of the right ends of membranelles by a movement of basal bodies associated with formation of the ribbed wall adjacent to the UM. In the old anterior oral apparatus a repetition of the processes of generation of a new outer UM row and sculpturing of right ends of membranelles takes place in synchrony with the corresponding events in the oral primordium, following prior shedding of the old outer UM row and loss of the sculptured pattern in association with temporary regression of the ribbed wall micro-tubules. Oral development is complex, with different processes involved in the assembly of the membranelles and the UM, and with a sequence of distinct events involved in the generation of each of these structures. Speaking comparatively, membranelle development follows the same pathway in many, perhaps all, ciliates in which these structures or their homologues develop from a common stomatogenic field.

Notes: . The temporal changes in the size and pH of digestive vacuoles (DV) in Paramecium caudatum were reevaluated. Cells were pulsed briefly with polystyrene latex spheres or heat-killed yeast stained with three sulfonphthalein indicator dyes. Within 5 min of formation the intravacuolar pH declined from ∼7 to 3. With the exception of a transient and early increase in vacuolar size, vacuole condensation occurred rapidly and paralleled the acidification so that vacuoles reached their lowest pH and minimal size simultaneously. Neutralization and expansion of vacuole size began when vacuoles were GT8 min old. No labeled vacuoles were defecated prior to 21 min after formation but almost all DV were defecated within 1 h so that the digestive cycle of individual vacuoles ranged from 21 to 60 min. Based on these size and pH changes, the presence of acid phosphatase activity, and membrane morphology, digestive vacuoles can be grouped into four stages of digestion. The DV-I are GT6 min old and undergo rapid condensation and acidification. The DV-II are between 4 to 10 min old and are the most condensed and acidic vacuoles. The DV-III range in age from 8 to ∼20 min and include the expanding or expanded vacuoles that result from lysosomes fusing with DV-II. The DV-IV are GD21 min old, and since digestion is presumably completed, they can be defecated. The rise in intravacuolar pH that accompanies vacuole expansion suggests that lysosomes play a role in vacuole neutralization in addition to their degradative functions. The acidification and condensation processes in DV-I appear to be unrelated to lysosomal function, as no acid phosphaiase activity has been detected at this stage, but may be related to phagosomal functions important in killing food organisms, denaturing proteins prior to digestion, and preparing vacuole membrane for fusion with lysosomes.

Notes: . Total DNA/organism was determined by flow cytometry on stocks of 33 single-cell-isolate clones and one strain of mithramycin-stained Trypanosoma cruzi. Interstrain differences in mean total DNA/group of 34% and interclone differences in total DNA/organism of 41% were found. Microspectrofluorometric analyses of the trypomastigote stage of selected clones confirmed the flow cytometry data and indicated that the total DNA/organism differences were due to differences in DNA of both the nucleus and kinetoplast with the nucleus being the major contributing factor. These data imply that the potential for genetic diversity in T. cruzi may be very large.

Notes: . The cortical membrane proteins of three gregarine and one coccidian species were compared using sodium dodecyl sulfate/polyacrylamide-gel electrophoresis. About 30 proteins were identified in the ghosts of Gregarina blaberae and G. garnhami and 20 in G. rhyparobiae ghosts and Sarcocystis tenella pellicles. No protein with the electrophoretic mobility of muscular actin was present in the ghosts of the sporozoan species under study. Each species possessed a characteristic electrophoretic pattern; no protein was present simultaneously in the four sporozoan species and only one protein band with a similar electrophoretic mobility was found in the three gregarine species (52 Kd protein). Two G. garnhami subpopulations living in Locusta migratoria and Schistocerca gregaria exhibited the same ghost protein pattern. Thus, large differences were observed between species and not within species, and the protein electrophoretic analysis appears to be a powerful tool for taxonomic investigations in gregarines. Gregarina blaberae and G. garnhami glycoconjugates were compared after periodate/Schiff staining of the polyacrylamide gel slabs. Several glycoconjugates were reported to belong to the cytoplasmic fraction; and, in view of cytochemical and ultrastructural data, a contribution of these glycocomponents to the secretion of a mucus is discussed.

Notes: . Phytomonas davidi is found in the latex of species of the plant family Euphorbiaceae, including Chamaesyce hirta and C. hyssopifolia, to latitude 32°N in the southeastern United States. The hemipteran Pachybrachius bilobata scutellatus (family Lygaeidae) serves as an agent of transmission from plant to plant. Heavy infections of flagellates in the salivary glands were observed; trypanosomatids were less than one-half the size seen in the plants and in the gut of the bug.

Notes: . Flagellar cysts of Blastocrithidia triatomae form from active flagellates by diminution in size. The pellicular microtubules disappear. The inner layer of the cell membrane thickens progressively as the organism shrinks. The fully formed cyst has an electrondense layer that corresponds to the outer layer of the unit membrane. An electron-lucent layer is approximately twice the thickness of the middle layer of the unit membrane. Inside that is a 92 nm layer that may represent the cytoplasm. The nuclear content is in the form of whorled bundles of 10–15 nm fibrils. The kinetoplast was not seen in electron micrographs of cysts.

Notes: A study of plankton samples collected in the Western Sargasso Sea during nine cruises has shown discontinuity between samples from different latitudes as regards their percentage, abundance, and number of species of Acantharia. Limits separating zones rich in Acantharia from those poor in Acantharia were singled out. The latitude at which the difference in abundance occurs can vary. This is in accord with differences in primary production, phytoplankton, and mesopelagic fishes noted by other workers who believe that the points of these faunal changes correspond to a temperature change indicated as “thermal fronts.”

Notes: A simple and rapid method is described for the isolation of nuclei from the Florida red tide dinoflagellate Gymnodinium breve. The nuclei are free of cytoplasmic contamination and are active in endogenous RNA synthesis. The ratio of DNA: RNA: acidsoluble protein: acid-insoluble protein is 1:0.39:0.13:0.63, respectively, and each nucleus contains ca. 113 picograms of DNA. Electrophoretic analysis of the acid-soluble proteins reveals the presence of two histone-like proteins with molecular weights of 12,000 and 13,000.

Notes: Proteins of surface membranes and surface-related cytoskeletons in Tetrahymena vorax microstomes and macrostomes were compared by one-dimensional SDS polyacrylamide gel electrophoresis to see if protein differences could be detected that correlate with the transformation from one phenotype to the other. Some differences were observed. However, these alterations appear to result from the heat-shock procedure used to synchronize the microstome-to-macrostome transition. The apparent lack of transformationspecific changes in cortical proteins is discussed. Similarities and differences between cytoskeletal proteins of T. pyriformis GL-C and T. vorax are also noted and discussed.

Notes: The growth inhibition of Tetrahymena furgasoni (once known as “T. pyriformis W”) by C19 and C21 steroids of similar structure was measured by determining cell population at 24 h and 48 h following addition of the steroid. A cis-fusion of the A/B rings junction, unsaturation at C-1,2, or C-4,5 and carbonyl substitution all enhanced inhibition, whereas the presence of two hydroxyl groups decreased inhibition. The results indicated that the transformation of C19 and C21 steroids by this protozoon may be part of a detoxication mechanism.

Notes: The metabolism of phospholipids in synchronous Plasmodium falciparum-infected erythrocytes was studied over one cycle of 48 h by the incorporation of labeled palmitate, serine, choline, and myo-inositol into cellular lipids. The rates of incorporation of palmitate and serine into total phospholipids and of choline into phosphatidylcholine (PC) were linear with the maturation of the parasite, increasing by a factor of 2–5.6 according to the precursors. The rate of inositol incorporation into phosphatidylinositol was 9.6 times higher at the schizont stage than at the ring stage, with a marked increase in the second half of the cycle. A significant incorporation of palmitate into triglycerides also occurred during the schizont stage of the parasite. The incorporations of serine and palmitate into phosphatidylethanolamine (PE) and PC showed a net increase at approximately the twentieth hour of the cycle, while the radioactivities recovered in phosphatidylserine (PS) had already reached a maximum by this time. These findings indicate an instantaneous transformation of PS into PE and PC through a decarboxylation of PS into PE, then a methylation of PE into PC during the second half of the cycle. Although PS is a minor component of the Plasmodium parasite, our findings demonstrate the important role of this phospholipid as a precursor of PE and PC, which are major constituents of parasite phospholipids.

Notes: With the aid of energy-dispersive X-ray microanalysis, several protozoa were tested for content of cations within inorganic minerals. The skeleton of acantharia consists mainly of Sr with small quantities of Ca and Ba. Two Loxodes species contain nothing but Ba, while in some Remanella species Sr with small quantities of Ba were present. In one Geleia species, Ca with small quantities of Sr was found; in two Trachelocerca species from Sylt (Germany), Ba is there in addition. Another Trachelocerca species from northern Italy lacked Ba, but did possess Mn. In Prorodon only Ca was found.

Notes: Thin-sectioning and freeze-etching electron microscopy were applied to explore the structure and the temperature- and Ca2+-response of the different host and parasite membranes during intraerythrocytic development of Plasmodium knowlesi in Macacca mulatta. The plasma membrane of uninfected erythrocytes is temperature- and Ca2+-responsive: chilling to 4°C and exposure to 5 mM Ca2+ induces a slight decrease in IMP-frequency and the emergence of small IMP-devoid patches on P-faces. On parasite infection, the erythrocyte membrane becomes modified as indicated by an enhanced temperature-response and the appearance of caveolae, ca. 70–90 nm in diameter. The frequency of these caveolae is increased in schizont-infected erythrocytes. Moreover, electron dense plaques, ca. 40 nm in width, appear just beneath the erythrocyte membrane in late trophozoites and schizonts, thus indicating a further modification of the host cell membrane during parasite development. The membrane of the parasitophorous vacuole, derived from the host plasma membrane, dramatically reduces the IMP-frequency especially on the P-face upon parasite infection. This leads to an apparent reversal of the IMP-distribution persisting throughout the whole infection cycle. The parasite plasma membrane forms local compaction domains with the nuclear envelope in ca. 30% of the ring-stages and trophozoites, which disappear in late trophozoites and schizonts. Moreover, the IMP-frequency on plasma membrane fracture faces almost doubles during parasite development. Chilling induces a decrease in the IMP-frequency on P-faces of the plasma membrane. Surprisingly, however, the parasite plasma membrane and the vacuolar membrane respond to externally applied Ca2+ with almost a doubling of the IMP-frequency. The different parasite endomembranes also undergo characteristic changes during parasite development.

Notes: The leech Calliobdella vivida (Verrill) is the vector of Trypanoplasma bullocki. At 10°C, infective-stage flagellates were first present in the leech's proboscis sheath five days after feeding. At 5°C, infective-stage flagellates were not present in the leech's proboscis sheath until 10 days after feeding, but at 20°C, flagellates were located there as early as 24 h after feeding. Infected leeches retained flagellates through three subsequent feeds on uninfected fish. When flagellates were first observed in hogchoker, Trinectes maculatus (Bloch & Schneider), they were much larger than infective stages from the leech. Average flagellate length then decreased during early acute phase, but gradually increased thereafter. Peak parasitemia was greater in a hogchoker inoculated by only one leech but held at colder temperature than in a hogchoker inoculated by 45 leeches, suggesting that temperature may be more important than inoculum in determining peak parasitemia. Cell division in the fish host is described. SEM studies of fish blood flagellates revealed a pre-oral ridge and a cytostome.

Notes: Histones were prepared from chromatin of the eukaryotic (endosymbiont) nucleus of Peridinium balticum (Levander) Lemmermann. The amino acid composition of whole histone was rich in lysine and similar to that of Olisthodiscus luteus and Euglena gracilis. Electropheretic analysis of these proteins in acidic-urea disc gels revealed four major bands: one with a mobility slightly lower than that of calf thymus HI; and three others which comigrated with calf H2B, H2A, and H4, respectively. The low mobility band was soluble in 5% perchloric acid and was sensitive to FeCl3 destaining. Electrophoresis in slab gels containing 0.1% SDS revealed five major components, with approximate molecular weights of 23,000, 20,000, 15,000, 13,000, and 11,000, respectively. The 15,000 and 11,000 dalton histones had mobilities identical to those of calf H3 and H4, respectively. The two highest molecular weight components were soluble in 5% perchloric acid. No bands were found to comigrate with calf H2A or H2B but a band was present that migrated to a position intermediate between calf H2A and H4 (13,000 dalton histone). Two-dimensional gels consisting of acidic-urea gels in the first dimension and SDS gels in the second dimension revealed that the 20,000 dalton component and the 13,000 dalton component are not resolved in the acidic-urea gel. As a working hypothesis, it is suggested that two of the five bands seen in SDS gels represent an H1-like doublet, and two are analagous to H3 and H4, respectively. The remaining histone may replace H2A and H2B.

Notes: The iodinating reagent 1,3,4,6,-tetrachloro-3α,6α-diphenylglycoluril (IODOGEN3) was used to label antigens on zygotes of Plasmodium gallinaceum with parallel studies using lactoperoxidase-catalyzed radioiodination for comparison. Proteins labeled by the IODOGEN method are most probably on the surface of the zygote, as the pattern of labeled proteins analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was very similar to the pattern of lactoperoxidase-labeled proteins. Furthermore, the labeled proteins represented only a subset of the total Coomassie Blue-stained proteins. The radioiodinated zygote proteins were immuno-reactive after IODOGEN or lactoperoxidase labeling. The IODOGEN method is technically much more simple than the lactoperoxidase method and does not require the addition of extraneous proteins or H2O2. The advantages of IODOGEN labeling, together with the essential equivalence of results obtained by these two, methods, make the IODOGEN method attractive for labeling parasite antigens in general.

Notes: A new method is described for mass cultivation of Euplotes aediculatus, a hypotrich ciliate containing omikron-symbionts. The ciliate cultures, continuously aerated in Erlenmeyer flasks (5000 ml) with 4500 ml medium, yield densities of 2300 cells/ml which are four to five times higher than cell densities of cultures grown in unaerated Fernbach flasks. Harvesting such cultures involves the application of 25-μm mesh sieves. Cells so concentrated can be purified by using columns or special chambers in which Euplotes migrates towards the cathodes in an electric field (field strength 7 V/cm).

Notes: Stocks of Entamoeba histolytica grown in a monoxenic culture system from the feces of nonhuman primates are compared with the eleven zymodemes of E. histolytica so far demonstrated from man. In a similar fashion, Entamoeba chattoni has also been grown and identified. Both E. histolytica and E. chattoni have been demonstrated in keepers of the primate collections. Comparisons have been made using the electrophoretic patterns of three enzymes: glucosephosphate isomerase [(GPI) E.C.5.3.1.9], phosphoglucomutase [(PGM) E.C.2.7.5.1], and L-malate—NADP+ oxidoreductase (oxaloacetate-decarboxylating) [(ME) E.C. 1.1.1.40]. Enzyme patterns of E. histolytica from the apes were found to be identical with three of those already demonstrated from man. The enzyme pattern of E. chattoni was distinctly different from that of any of the E. histolytica zymodemes. Other protozoa found in the single fecal sample examined from each subject are also listed.

Notes: . Amphidinium carteri was unable to grow on nutrient-enriched seawater in the presence of 200 μg/ml fluoride (F) but could be adapted to grow successfully on this F concentration when repeatedly cultured with stepwise increases in sub-inhibitory F concentration. Electron microscopic investigation of the F-adapted dinoflagellate cells showed abnormal ultrastructural features in the chloroplast (especially the pyrenoid), mitochondria, and nucleus. Simultaneous comparison with the F-inhibited dinoflagellate cells showed that thylakoid formation was extremely disorganized by fluoride and that F-adaptation conferred a prolamellar-like configuration on the thylakoids in the center of the pyrenoid. This unexpected appearance of lamellae formation in the F-adapted cells suggested that the pyrenoid may be a center for thylakoid assembly. Such cells also showed large, intensely osmiophilic inclusions in the mitochondria. Microbodies are found in close juxtaposition to the mitochondria and chloroplast, suggesting an increased metabolic dependence on photorespiration. The F-adapted nucleus showed dark and light concentric rings in the nucleolus region, accompanied by other signs of mitotic activity, which were not observed in the F-inhibited cells. It was inferred that the F-adaptation may have required some form of genetic change resulting presumably in the development of a phenotype mutant.

Notes: . The large fresh-water microaerobic amoeba Pelomyxa palustris does not contain mitochondria, but three types of bacterial endosymbionts are always present. Thus, it is of interest in the discussion of the possible origin of mitochondria from primitive prokaryotes. Gas exchanges (O2, CO2) and concentration of endosymbionts were determined in individual amoebae, in which the life cycle stage was noted. Grey type (stationary phase) amoebae had a lower O2 uptake and lower endosymbiont concentration than light type (growth phase) amoebae, and highest O2 uptake was found in centrifugal pieces of light type Pelomyxa, centrifuged in vivo, which contained nearly all of the endosymbionts. In light type amoebae, the respiratory activity was independent of O2 concentration between 1 and 21%, and, when compared on the basis of dry weight and protein, of the same order as that of other free-living protozoa. The R.Q. was slightly higher than 1, indicating that glycolysis does not play a significant role in energy metabolism. It is concluded that P. palustris is fully aerobic, and suggestions are presented as to the role of the endosymbionts in its respiratory metabolism.

Notes: . A series of new in vitro systems for the cultivation of bloodstream forms of Trypanosoma (Trypanozoon) brucei brucei, T. (T.) b. rhodesiense, and T. (T.) b. gambiense was developed. The standard system consists of a feeder layer of fibroblast-like cells derived from embryos of New Zealand White rabbits (REF) or a mountain vole, Microtus montanus (MEF), with HEPES-buffered Minimum Essential Medium (MEM), with Earle's salts, supplemented with 15% inactivated rabbit serum. These two and other feeder layers were cross-checked with different sera to test for growth support of bloodstream forms of the three trypanosome subspecies studied. Cultures could be initiated with bloodstream forms from mammalian hosts or from cryopreserved stabilates. Metacyclic forms from infected Glossina m. morsitans could also be used as inoculum; they transformed within 6 h to bloodstream forms. Maintenance of cultures and growth properties are described in detail. Experiments were undertaken to confirm that the cultivated bloodstream forms still possess some of the characteristic features of pleomorphic bloodstream populations. Cultivated bloodstream forms were always infective for mice, and a surface coat could be demonstrated by electron microscopy. They could also be cyclically transmitted through tsetse flies, and the metacyclic forms from these flies could be brought back into culture. In vitro cloning with single bloodstream forms and metacyclic forms could be achieved with high cloning efficiency. The consumption of glucose and the production of pyruvate and lactate were determined.

Notes: Fathead minnows, Pimephales promelas, raised from eggs in the laboratory, were experimentally infected with oocysts of Eimeria iroquoina from either P. promelas or the common shiner, Notropis cornutus. Within intestinal epithelial cells, trophozoites thought to be derived from the sporozoites contained a prominent electron-dense refractile body. Merozoites dedifferentiated into trophic forms by losing components of their apical complex and pellicle. The inner membrane components of the pellicle appeared discontinuous, and the micronemes became enclosed within vacuoles. Prior to merozoite formation, multinucleate meronts were limited by a single membrane. Golgi complexes were associated with the nuclei of this stage. Merozoites were formed by ectomerogony in one generation and by endomerogony in the final generation. In both forms of merogony the final nuclear division was coupled with the onset of differentiation of the merozoites and featured eccentric mitotic spindles associated with centrocones located within the nuclear envelope and with the precursors of the apical complex. A Golgi complex was closely associated with the nucleus and apical tip of the forming merozoite. Unlike other Eimeria species, the complete pellicle of the merozoites of the final asexual generation of E. iroquoina was formed within the cytoplasm of the meront, without association with the limiting membrane, thus, all pellicular components are synthesized de novo. The inner membranes of the pellicle initially appeared as longitudinal strips, each of which was associated with a pair of the 22–24 subpellicular microtubules. Mature meronts of the final asexual generation averaged 9 μm in diameter and produced 13–16 merozoites. With the exception of the internal completion of the pellicle of the final generation merozoites, the basic processes of merogony in fish Eimeria species are similar to those recorded in terrestrial hosts.

Notes: The glycerophospholipids of the protozoon Tetrahymena pyriformis W are unique in that the polyunsaturated fatty acid γ-linolenate (18:3Δ6,9,12) is a major component of both the sn-C-1 and sn-C-2 positions. Tetrahymena were incubated with [1-14C]γ-linolenate. The positional distribution of the radiolabeled fatty acid in the three major glycerophospholipids was determined. [1-14C]γ-linolenate was found at both carbons of the three lipids, in general agreement with the mass distribution of γ-linolenate, except for markedly greater labeling at the sn-C-2 position of phosphatidylcholine. We hypothesize that an acyltransferase exists in Tetrahymena that can esterify γ-linolenate at both carbons during glycerophospholipid biosynthesis.

Notes: Promastigotes of Leismania donovani cultured for either 3 or 10 days in vitro and inoculated intracardially into golden hamsters with an equal number of organisms from either population showed a 7-fold difference in infectivity when compared at both 10 to 16 days post-infection. Reproducible histochemical staining for the promastigote enzymes glucose-6-phosphate dehydrogenase (G6PDH) and peptidase after polyacrylamide gel electrophoresis showed two isoelectric variants of G6PDH (Bands 1 and 2) that displayed a 45% decrease (Band 1) and a 60% increase (Band 2) in total activity when 3- and 10-day-old promastigores were compared. Peptidase activity, present in a single band, increased 7-fold in 10-day-old promastigotes. A decrease in the lectin-induced agglutination of promastigotes by castor bean agglutinin (RCA60), specific for D-galactose and N-acetyl-D-galactosamine, was seen when 3- and 10-day-old promastigotes are compared. Antisera raised against sonicated 10-day-old promastigotes showed a unique precipitin band between the antiserum and sonicated 10-day-old promastigotes not found between the antiserum and sonicated 3-day-old promastigotes.

Notes: The compound 6-(L-erythro-1,2′,3′-trihydroxypropyl)pterin, at a concentration of 50 pg/ml (“L-erythro-neopteria”), supports half-maximal growth of Crithidia fasciculata; biopterin at a concentration of 30 pg/ml is shown to yield similar growth. N2-dimethyl-6-(L-erythro-1′,2′,3′-trihydroxypropyl)pterin (A) was inactive even at 100 ng/ml. Synergism was observed with the N2-dimethylamino derivative (A) in the presence of suboptimal biopterin, its activity then being of the order of L-erythro-neopterin. In contrast, the stereoisomeric N2-dimethyl-6-(D-erythro-1′,2′,3′-trihydroxypropyl)pterin (“dimethyl-D-erythro-neopterin”) and its 3′-mono-phosphate only slightly enhanced growth under similar conditions but both threo-isomers had no supplementary activity. Biopterin-induced growth was slowed by 6-(D-erythro1′,2′,3′-trihydroxypropyl)pterin (D-neopterin); the threo-isomers had no such effect. An adaptive demethylation capacity by growing cultures and competition of biopterin uptake by D-neopterin seems likely. The report of the occurrence in Euglena of N2-dimethyl-6-(L-threo-1′,2′,3′-trihydroxypropyl)pterin and its 3′-mono-phosphate adds further interest to our observations.

Notes: We investigated the macronuclear DNA genomes of several marine and fresh-water ciliates. The marine forms studied were: Uronema nigricans, Parauronema virginianum, Parauronema acutum, and two strains of Miamiensis avidus; the fresh-water ciliates included: Tetrahymena pyriformis, Paramecium octaurelia, and P. caudatum. The organisms were cultured axenically and the DNA extracted from isolated and purified macronuclear preparations. Reassociation rate constants of purified DNA preparations used to calculate kinetic complexity were determined both optically and by hydroxyapatite chromatography. Analytical complexity was determined chemically. Ciliate macronuclear DNA appeared to reassociate as a single unique sequence, except for a small fraction (4% of the total DNA) that was repetitive and renatured rapidly. Values for the kinetic complexities of macronuclear DNA in these forms varied over a relatively narrow range, from 1.5 to 3.8 times 1010 daltons, and were only 7–15x larger than that of the bacterium Escherichia coli. On the other hand, values for analytical complexities of macronuclear DNA of marine and fresh-water ciliates varied over two orders of magnitude and were related to the size of the animals. It is suggested that ploidy levels of macronuclear DNA in these ciliates may represent a functionally permanent amplification of the genome.

Notes: Variations in DNA levels for log-phase Euglena have been shown to be directly related to the pH of the culture medium. Data are presented here for cultures grown in Cramer and Myer's medium at pH 3.0 and 6.8. DNA levels are ∼50% greater for Euglena at the higher pH value, confirming earlier reports.

Notes: Guanylate cyclase activity decreased during the division phase of heat-shock synchronized Tetrahymena pyriformis, strain GL. However, when Ca2+ was removed by EGTA to negate the effects of the Ca2+-binding protein (calmodulin), which is required for the full activity of guanylate cyclase in this organism, no significant change in the enzymatic activity was observed throughout the cell cycle. On the other hand, the reduced guanylate cyclase activity at division phase was associated with a decreased level of calmodulin content. These results suggest that fluctuations in guanylate cyclase activity during the cell cycle would be dependent on the concentration of calmodulin.

Notes: Identification and characterization of kDNA is described in the naturally occurring totally dyskinetoplastic species Trypanosoma equinum. Fluorescence microscopy of live cells, using the highly sensitive and specific probe DAPI (4,6,-diamidino-2-phenyl-indole), showed the presence of a diversity of extranuclear fluorescent bodies scattered along the length of the organism. Transmission electron microscopic studies revealed a close similarity between the distribution of these DAPI-fluorescing particles and of dense aggregates of nonfibrillar material resembling the kDNA of dyskinetoplastic strains of other species. Variable sized remnants of kDNA, occurring singly or in clusters, were found scattered throughout the mitochondrion. Analytical cesium chloride ultracentrifugation of total cellular DNA extracts showed a kDNA banding profile at a buoyant density equal to 1.691 gm/cm3, representing approximately 11% of the total cellular DNA content. Molecular spreads of isolated kDNA revealed a population of open circular molecules ranging in contour length from 0.11–9.69 μm.

Notes: Morphogenesis in Conchophthirus curtus has been investigated by the use of protargol silver impregnation supplemented by selective use of scanning electron microscopy. Events are assigned to nine sequential stages; the last, stage 9, which involves maturation of the somatic ciliature and infraciliature as well as the final development of the buccal cavities of both proter and opisthe, occurs following cytokinesis. Stomatogenesis involves both the parental haplokinety and the deep kinetosomal unit (DKU). In perhaps a unique phenomenon, phylogenetically, the ciliated parental haplokinety forms the early oral primordium of the opisthe and is replaced in the proter by the DKU. The DKU then acts as a formative center for new kinetosomes that migrate into the developing opisthe primordium. Late in the process, the haplokinetal primordia of both proter and opisthe give rise to their respective DKU's. Some events of nuclear activity and somatic development are also described. The high degree of structural differentiation of this ciliate has provided the opportunity to examine temporal relationships during morphogenesis. We have found that somatic, buccal, and nuclear events proceed in a tightly coupled sequence. Hence, somatic and nuclear development can be directly correlated with the nine stages of stomatogenesis.

Notes: The interaction of Leishmania with lysosomes within macrophages in vivo has been investigated. Lysosomes labeled with colloidal gold in vivo fused with phagocytic vacuoles containing Leishmania amastigotes within the macrophages of infected footpad tissue of BALB/c mice. This localization of Leishmania within macrophage phagolysosomes in vivo is the first confirmation for any obligate intracellulaire protozoon that parasite-lysosome interactions in vitro occur in vivo.

Notes: The life cycle of Caryospora bubonis was studied in the Great Horned Owl. Owls fed sporulated oocysts became patent on days 8–13, and peak oocyst production occurred between days 14 and 18. Owls fed infected mice became patent on days 8–10, and peak oocyst production occurred between days 9 and 13. The reduction in length of the life cycle in owls fed infected mice provides evidence that both indirect and direct life cycles can occur in this species and suggests that parallels exist in the lives of various isosporid, eimeriid, and other coccidia that may not have been sufficiently appreciated in the past.

Notes: Species of Eimeria occurring in fishes show important differences, especially in their life cycles, with respect to what is known for those forms found in mammals or other hosts. In some cases, at least, some small invertebrate may play the role of vector or intermediate host. Present studies of fish coccidia may throw light on the possible evolution of certain aspects of host-parasite interrelationships involving eimerian species in particular: for example, the earliest site (perhaps not the gut) of infection and even the “original” host group (perhaps invertebrates rather than vertebrates).

Notes: Problems of the taxonomy and, especially, of the nomenclature of various species of coccidia of direct importance to humans are further discussed. The diversity of host potential and site selection is also mentioned, with the prediction that, hopefully, our knowledge will be much greater 15 years from now than it presently is.

Notes: The use of drugs in domestic animals is dominated by considerations of cost-effectiveness and profitability. They are extensively used against coccidial infections of poultry where they are an important factor in intensive husbandry. Ionophore antibiotics, which dominate this field, may have applications in ruminants. Imidocarb is of therapeutic and prophylactic value against babesial infections and there are new prospects for control of theileriasis. Effective drugs for the control of African trypanosomiasis are limited and attention is being given to alternative uses of available compounds.