ALBERT

Notes: Electron microscopy was used to examine the flagellar apparatus of Herpetomonas ampelophilae from the gut and malpighian tubules of Drosophila melanogaster. The flagellates attach to the microvilli either by weaving their flagella between the microvilli or by engulfing several microvilli with an external flagellar membrane. The first type predominated in the gut while the second type was limited to the malpighian tubules. Desmosomes were not involved in either type of attachment. A subpellicular collar with emerging microtubules was found to be adjacent to the desmosome of the flagellar pocket of herpetomonads in the gut.

Notes: Prorocentrum micans Ehrenberg, a free-living marine dinoflagellate, was used to test the intracellular toxic action of cadmium. The cells were cultivated in Erdschreiber medium, with Cd concentrations of 10–100 ppb. Thin sections of treated cells, examined ultramicroscopically, exhibited vacuolations, increased numbers of lysosomes, and severe mitochondrial damage. The first two alterations are a general response to toxicity; the third is Cd specific. Although some chloroplasts were affected by Cd, they were not very sensitive to its action. The nuclear apparatus was not morphologically affected.

Notes: Toxoplasma-like avian parasites inhabiting mononuclear phagocytes have been called Haemogregarina, Toxoplasma. avian Toxoplasma, Atoxoplasma, and Lankesterella by various authors. My attempts to transmit the parasites by bloodsucking mites or by transfer of blood and tissues of infected sparrows and canaries were unsuccessful. However, it was noted that the infection was exacerbated under conditions that favored transmission of coccidiosis: crowding and lack of cleanliness. Oral inoculation of sporulated oocysts of Isospora resulted in death from overwhelming macrophage infection with Toxoplasma-like organisms. Experiments using sparrows and canaries showed that the Isospora species involved was not cross infectious. Further investigations using canaries demonstrated that after oral oocyst inoculation, infection of macrophages spread from the submucosa of the duodenum to the liver. spleen, and lungs. After several generations in the internal organs, asexual multiplication, occured in the intestinal epithelium of the small intestinc. Fecal oocysts first appeared at the end of 9–10 days. Oocysts continued to be passed in the feces for months after infection. This chronicity may be explained by the relatively long life of the macrophages that serve as host cells for the asexual stages as compared to the intestinal epithelium which is the cell type parasitized by conventional coccidia.

Notes: Stages of mitosis of the micronuclei of Stentor coeruleus were described as seen by transmission electron microscopy. Cells in division and those regenerating new oral membranelles were studied. Microtubules were found in early prophase in the karyoplasm and interspersed between the condensing chromatin. A monaxial intranuclear spindle is formed by early metaphase, with kinetochore microtubule attachment sites on the chromosomes. The spindle elongates, separating the daughter nuclei at anaphase. A new nuclear envelope, consisting of two unit membranes, begins to form at late anaphase. Small segments of membrane found in the space between the newly forming and the old micronuclear envelopes appear to fuse to form the new nuclear envelope. No ultrastructural differences were found in the mitotic nuclei of cells in division or regeneration.

Notes: SYNOPSIS. Cortical ultrastructure of the scuticociliates Dexiotricha media and Dexiotricha colpidiopsis was investigated. The following elements of the somatic cortex were studied: the cell membrane, alveolar membranes and the epiplasm, kinetodesmal fibers, postciliary and transverse microtubular ribbons, and transverse fibers associated with single and paired kinetosomes; mitochondria and single microtubules located in interkinetal ridges; mature and early extrusion stages of mucocysts: the expulsion vacuole pore and tube, the nephridioplasm and the cytoproct. In the buccal cortex, the paroral kinety-ribbed wall complex, the 3 polykineties, and the cytostome-cytopharynx were investigated.Comparative survey of ciliate ultrastructure indicates 2 principal orientation patterns for kinetodesmal and postciliary fibers, recognition of which leads to reevaluation of the theory of paroral kinety formation and the ideas of homology based on this theory. Ultrastructurally, the scuticociliates are not distinct from tetrahymenines and peniculines; the 3 groups appear to be 1 assemblage.

Notes: SYNOPSIS. In this study the characteristics of the synthesis of DNA and RNA in the nuclei of Loxodes were investigated. Loxodes striatus is a primitive ciliate with 2 pairs of structurally differentiated diploid nuclei, the macro- and micronuclei. The macronuclei are differentiated morphologically into a clearly recognizable central core and an outer zone.To determine DNA and RNA synthesis, individual organisms were analyzed by autoradiography after incubating groups of cells with a 3H-labeled precursor ([3H]thymidine for DNA and [3H]uridine for RNA).The following observations were made: (A) All portions of macro- and micronuclei appeared to contain DNA as judged by the localizations of incorporated [3H]thymidine. (B) The macro- and micronuclei did not synthesize DNA at the same time; moreover, the duration of DNA synthesis in the former was much longer than of the latter nucleus. (C) Replication of DNA in the inner core and outer zone of the macronucleus occurred at separate times with little if any overlap. (D) All of the detectable [3H]uridine incorporation was found in the macronucleus and none in the micronucleus. Within the macro-nucleus the central core was more heavily labeled. (E) The quantitative differences in the label of the different components of the nuclear complex were investigated. (F) Contrary to the previously reported information our results suggest that DNA synthesis can occur in adult macronuclei.The possible explanation of these results is discussed in the context of the nuclear evolution of ciliates and of recent information on nuclear differentiation.

Notes: SYNOPSIS. Eimeria dispersa (turkey strain) and Eimeria gallopavonis sporozoites were inoculated into primary cultures of chicken kidney (CK) and turkey kidney (TK) cells. Eimeria dispersa sporozoites were more infective in either cell type than those of E. gallopavonis: at 4 hr, the percentage of infection was 67-98 for E. dispersa but only 23-56 for E. gallopavonis. E. dispersa also survived better in culture: at 2 days, losses of E. dispersa in both cell types were only 4-19%, whereas losses of E. gallopavonis were 35-47% in TK cells and 60–95% in CK cells. However, E. gallopavonis developed further than E. dispersa. Location and increase in numbers of intracellular stages at 4 days indicated that E. dispersa proceeded through 2 schizogonic generations before development stopped.

Notes: Book reviewed in this article:Cuatrecasas, P. & Greaves, M. F., eds. 1976, Receptors and Recognition, Vol. I, Series A.

Notes: SYNOPSIS. A mating type analysis was performed on 231 isolates of the cellular slime mold, Polysphondylium pallidum found in 61 samples collected in eastern North America between northern Florida and southern Canada. Seventy-eight percent of the isolates belonged to one of 2 mating types; 18% were incapable of mating with any partner; 3% were homothallic; and 1%, consisting of 2 isolates from a Florida sample, belonged to a separate breeding group. It is suggested that the majority of isolates represent a species capable of local genetic adaptation to a niche, the parameters of which undergo considerable variation over space and time.

Notes: Book reviewed in this article:Avakyan, A. A. 1976. Atlas Anatomii Prosteishikh, Patogen-nykh dlya Cheloveka i Zhivotnykh.

Notes: SYNOPSIS. Endosymbiotic algae from Paramecium bursaria when added to the culture medium are ingested by Chlorella-bearing P. bursaria at a rate of 2,000 algae/organism/day. That the ingested algae are digested and assimilated by the ciliates is suggested by the more rapid growth of Paramecium when algae are added to the medium (G= 40 hr with algae compared to 190 hr without). The digestion by the ciliates of exogenous algae contrasts with the survival of these algae under normal growth conditions. It is suggested that the protection of the endogenous algae is related to their location in peripheral perialgal vacuoles.

Notes: SYNOPSIS. Cell size, macromolecular composition, carbohydrate utilization patterns, and O2 concentrations were measured throughout the growth stages of Naegleria gruberi in agitated cultures in a complex medium. Biphasic logarithmic growth occurred during the initial 83 hr of growth and the mean generation time was 7.0 hr and 19 hr during initial and secondary log growth stages, respectively. The maximum yield was 5 × 10* amebaeJml. The pH rose rapidly (1 pH unit) during the secondary log growth phase (52-83 hr) and continued into the stationary growth phase (83-120 hr). Dry weight, total protein, carbohydrate, and RNA per ameba increased just before the secondary log growth phase. RNA increased 31% to 35% per ameba at the end of each phase of log growth. DNA increased ∼ 2-fold throughout the different growth phases. Average cell size increased 90% during biphasic log growth then decreased during stationary phase. O2 tension decreased from 100% to 18% of saturation during the biphasic growth phase, then increased during stationary growth to near 100% saturation. Glucose and total carbohydrate assays showed little utilization of those substrates throughout the growth stages. Naegleria gruberi presumably has a predominantly aerobic metabolism, also its metabolism may change during the different growth phases.

Notes: SYNOPSIS. Toxoplasma ranae sp. n. is described from the brain of a leopard frog, Rana pipiens, probably from Mexico. Its pseudocysts were 72(55-106) × 48(29-70) μm in fixed sections. They contained an average of ∼ 4,000 slightly curved elongate zoites measuring 4–5 × 0.5 μm, with a central, spherical, vesicular nucleus.

Notes: Book reviewed in this article:Pennycuick, C. J. 1974. Handy Matrices of Unit Conversion Factors for Biology and Mechanics.

Notes: SYNOPSIS. Egestion of carmine particle-containing food vacuoles from the cytoproct of Tetrahymena pyriformis has been analyzed by high-speed cinemicrography. The vacuole may enter into position in the cytoproct ∼ 7 sec before ejection, and forms a distinct bulge beyond the outline of the cell surface for over 2 sec prior to ejection. The ejection process itself requires 20–80 msec.

Notes: SYNOPSIS. Blood films were examined from 1477 birds of Taiwan (193 species, 49 families). Haemoproteus Kruse was by far the commonest parasite, with Leucocytozoon Danilewski a not very close second. It is probable that some of the Haemoproteus infections represented new species, and 1 occurring in the Bamboo Partridge (Bambusicola thoracica sonorivox Gould) seemed characteristic enough to justify recognition as such; the name Haemoproteus bambusicolae sp. n. is proposed for this organism. Malaria was found in 77 birds, the greatest number of infections occurring in the Bamboo Partridge. Most of them were caused by Plasmodium juxtanucleare Versiani & Gomes, a pathogen of chickens, but a number were due to an undetermined species of Plasmodium. The Bamboo Partridge may be a reservoir host of the former. A few other identified species (P. rouxi Sergent & Sergent, P. hexamerium Huff, P. tenue Laveran & Mesnil) were seen, as well as some unidentified ones. Plasmodium tenue was seen in Garrulax canorus taewanus Swinhoe, a babbler: until now it was known only from the Pekin Robin (Leiothrix luteus Scopoli), also a babbler, in which we have found it extremely common. Sixty-four microfilarial infections were identified; they were especially frequent in the Button Quail (Turnix suscitator rostrata Swinhoe).

Notes: SYNOPSIS. Short pulse-labeling of log phase Crithidia fasciculata cells with [3H]thymidine allowed the autoradiographic visualization of 2 sites of replication of kinetoplast DNA situated at the periphery of the networks and separated by 180°. Longer pulse-labeling led to the previously reported total peripheral labeling pattern. Pulse-labeled networks possess an intermediate density in ethidium bromide-CsCl equilibrium gradients between the densities characteristic of closed networks and open or linear DNA. Removal of ethidium bromide by several methods and treatment of intermediate band networks with RNase and pronase had no effect on the equilibrium rebanding pattern. Closed minicircles of Leishmania tarentolae are not labeled by a short pulse of intact cells with [3H]thymidine. A chase of ∼ 3–4 hr is required for the appearance of radioactivity in closed minicircles, a time delay which implies the existence of intermediate events between replication and eventual covalent closure of the minicircles.

Notes: SYNOPSIS. DNA synthesis during growth and differentiation in Naegleria gruberi strain NEG populations has been studied. Autoradiography of cells labeled with [3H]thymidine revealed that grains are concentrated over the nuclei in logarithmically growing populations of cells, whereas in differentiating cells, grains are scattered over the cytoplasm; i.e. no significant nuclear labeling is detectable. It was established by MAK chromatographic analysis that [3H]thymidine is incorporated into double-stranded DNA in Naegleria and that the actual amount of incorporation in the logarithmically growing populations of cells is 20 times greater than that in differentiating cells. These results suggest that nuclear DNA synthesis is reduced markedly soon after the initiation of differentiation, while cytoplasmic DNA synthesis continues. It was established from cell cycle analysis that the approximate intervals of G1, S, G2, and M phases were 180, 183, 90, and 28 min, respectively. Hence, the reduction in the nuclear DNA synthesis in differentiating cells is not due to the inhibition of initiation of DNA replication, but rather to the termination of the DNA replicating process. Thus DNA synthesis is curtailed in the presence of RNA and protein synthesis which are required for differentiation.

Notes: SYNOPSIS. The activity and sedimentation of acid phosphatase (APase), acid deoxyribonuclease (DNase), and acid ribonuclease (RNase) were investigated throughout growth and encystment in Acanthamoeba castellanii. The activities/mg protein of all 3 hydrolases are high in young cultures and decrease to constant levels in postlog cells. The RNase activity/ ameba decreases 50% during growth, whereas the activity/cell of both APase and DNase remains constant. The percent sedimentation at 20,000 g of all 3 enzymes gradually increases from about 40% in midlog to a plateau of 80% in postlog cells. During encystment, the sedimentation behavior of RNase differs from that of APase and DNase. Encystment is characterized by a differential decrease in the activity/cell of the 3 hydrolases, with RNase decreasing most rapidly and APase least rapidly. APase is unique in that a transient increase of its specific activity is noted during encystment, even though its activity/cell is decreasing.

Notes: SYNOPSIS. In cultures of Platymonas subcordiformis Hazen, grown in appropriate light-dark cycles, as many as 75% of the cells adhered to the surface of the glass culture vessel toward the end of the light period of each day. Cell division occurred primarily while the cells were attached. Subsequently, motile daughter cells were released into the growth medium by the rupture of the mother cell theca. The settling behavior appears to be an integral part of the life cycle being synchronized to the same extent as cell division.

Notes: SYNOPSIS. The coccidian parasite Eimeria gadi was found in the haddock, Melanogrammus aeglefinus, taken from the Nova Scotian fishing banks. The haddock infection rates ranged from a high of 58% on Emerald Bank to a low of 4% on Georges Bank, the average being 32%. There was no relationship between sex and degree or prevalence of infection. Although the probability of an occurrence of infection increased with size, small fish with heavy infections were observed. The degree of infection had no apparent effect on the condition factor (length/weight) of the fish. The infection rate reached a maximum in the fall of the year while the heaviest infections were observed in the spring. It is evident from the data that the infection is fatal.The parasite mass, appearing as a creamy viscous to a yellow semisolid material in the swimbladder, consisted of various parasite stages, fibrous and cellular debris, and lipid material. Some aspects of the sporocyst stage are described.No other gadoids from the Nova Scotian banks were found to be infected; however, a single specimen of the fourbeard rockling, Enchelyopus cimbrius, from St. John's, Newfoundland, was found to be heavily infected with E. gadi.

Notes: SYNOPSIS. Synthesis of RNA in the macronucleus and appearance of RNA in the cytoplasm were studied in heat synchronized Tetrahymena pyriformis GL and compared to those found under conditions of logarithmic growth (28 C) and during heat shocks (34 C).In macronuclei of logarithmically growing cells precursors were processed to 2 rRNA species (25S and 17S). In addition, another RNA (15S), more homogeneous than the RNA (8-15S) in the cytoplasm, was observed in the macronucleus. Both 17S and 25S rRNA species were found in the cytoplasm, 17S rRNA appearing more rapidly than 25S rRNA. Synthesis of rRNA was suppressed at 34 C in cells subjected to heat synchronization; 8-15S RNA synthesis appeared to be inhibited to a lesser extent.During the time preceding the first synchronized division, the synthesis of rRNAs in the macronucleus slowly recovered. Early in the cycle, almost no newly synthesized rRNAs were extracted. By 30 min after the last heat shock (EH), most of the RNA synthesized was not identified as rRNA. By 60 min after EH, the pattern of RNA synthesis had not returned to that observed in logarithmically growing cells.

Notes: SYNOPSIS. Cell-free preparations of Acanthamoeba castellanii trophozoites transfer glucose from UDP-[U-14C]glucose to a chloroform-soluble form. This radioactive material has been isolated by thin-layer chromatography; it contains an alkali-labile and an alkali-stable (unsaponifiable) component. Treatment of the enzymic product with 0.1 N KOH for 15 min at 0 C or 20 C releases radioactivity into the aqueous phase as glucose. During this treatment, 30–60% of the original glycolipid remains chloroform-soluble. It is considered to be an alkali-stable glycolipid because no further loss of radioactivity occurs during an additional 45-min of treatment with 0.1 N KOH. During incubation with 0.1 N HCI at 100 C glucose is released quantitatively from both the untreated glycolipid and the alkali-stable glycolipid with a half-time of 6 min. Glycolipid formation is inhibited by UDP and is reversible; extracts catalyze the formation of UDP-glucose from the alkali-stable glucolipid and UDP.The chemical and physical properties of the alkali-stable glycolipid are consistent with a glucosyl phosphoryl polyprenol structure. Extracts prepared from cysts catalyze the formation of glycolipids aiso, but the glucosyltransferase activity/cell decreases during the course of encystment. Radioactivity is incorporated into the fraction insoluble in chloroform-methanol-water (1:1:1:) during these incubations when UDP-[U-14C]glucose or [14C]glycolipid is the substrate.

Notes: SYNOPSIS. In populations of Euglena gracilis strain Z synchronized by cultivation on a repetitive light-dark cycle, chloroplasts undergo cyclic changes in structure. During most of the light period chloroplasts are relatively compact with closely appressed lamellae; during the dark (division) period the chloroplasts become quite distended. This change persists for at least one cycle even when the cells are left in continuous light, suggesting that the periodicity may be related more to the age of the cell than to a direct effect of light. In addition, the pyrenoid in synchronized cells has a transient existence, being present only in the first half of the light period.

Notes: SYNOPSIS. Although large hemoglobin inclusions are observed in intraerythrocytic Babesia microti parasites, they are absent from parasites freed of hamster red cells by immune lysis with antihamster erythsocyte serum. Babesia microti has no cytostome. This parasite, therefore, does not appear to feed by phagocytosis of large boluses of hemoglobin, as does Plasmodium. To determine whether Babesia can pinocytose protein, free parasites were fed ferritin in an in vitro system. Ferritin was taken up from the entire cell surface into narrow channels within 15 min at 37 C. Only merozoites, with their pellicular complex, failed to take up the protein. By 60 min, the ferritin was highly concentrated in many channels and vesicles, which formed interconnecting stacks. The ferritin-containing channels became associated with membrane whorls of the multimembranous structure. Membrane whorls were also observed in the process of extrusion in samples incubated for longer times. These events may represent steps in the digestion and excretion of the pinocytosed protein. Empty channels formed when Babesia was fed albumin. The diaminobenzidine reaction for hemoprotein was positive for the channels in both free and intraerythrocytic babesias. The staining reaction was completely inhibited by cyanide, but not at all by aminotriazole. These results further suggest that Babesia pinocytoses hemoglobin in vivo. Plasmodium lophurae parasites freed of red cells by immune lysis are surrounded by 2 membranes and apparently can ingest ferritin only through the cytostome. Extracellular cytostomal feeding involves both membranes, as it does in vivo. Ferritin was found in food vacuoles, some of which contained hemoglobin ingested before parasite isolation, connected to or near the cytostome. In both Plasmodium and Babesia low temperature inhibited ferritin uptake.

Notes: SYNOPSIS. During the course of infection in the rat, Trypanosoma lewisi produces 2 antigenic variants: the 1st represents the initial, reproducing population of cells; and the 2nd the nonreproducing, ablastin-inhibited adult population. The specificities of the agglutinins elicited by the variants were studied by adsorption and agglutination methods and the newer immunoelectroadsorption technic. It was found that the reproducing variant has a surface antigen that reacts with the agglutinin specific for the adult variant, but this antigen does not become immunogenic until transformation to the adult variant occurs. It was also found, with fractions of immune sera obtained by gel filtration, that the agglutinin specific for the reproducing variant is IgG and that specific for the adult variant, IgM. The antigenic variants of pathogenic and nonpathogenic trypanosomes are compared, and the roles of trypanocidal and ablastic antibodies in the induction of antigenic variation are discussed.

Notes: SYNOPSIS. Living Trypanosoma musculi bloodstream trypomastigotes were agglutinated specifically with concanavalin A (ConA), wheat germ agglutinin (WGA), soybean agglutinin (SBA), and fucose-binding protein (FBP). The agglutination with these lectins of living cells from which the coat was removed by trypsinization was the same as with intact trypanosomes. Glutaraldehyde or formalin fixation did not affect the results with regard to agglutination with WGA, SBA, and FBP, but lower agglutination with ConA was observed upon fixation. By using a dense iron-dextran marker many fewer ConA marker particles were localized at the fine structural level in the intact than in trypsin-treated trypanosomes. On the basis of the results obtained by agglutination and electron microscopy, it is likely that fixation cross-links intact surface-coat components associated with the ConA binding sites. It is evident from the studies in which lectins were employed that ligands containing α-D-mannose, N-acetylglucosamine, N-acetylgalactosamine, and α-L-fucose are randomly distributed in the outer surface of the pellicular and flagellar membranes of T. musculi trypomastigotes. Results obtained with α-amylase- and dextranase-treated trypanosomes suggested that lectin-binding sugar ligands in the cell surface were not directly associated with α-1,4 or repetitive α-1,6 glucan-bonded polysaccharide moieties. Similar conclusions can be drawn on the basis of neuraminidase treatment with regard to N-acetylated neuraminic acids.After thorough washing, intact, but not trypsin-treated trypomastigotes were agglutinated specifically with antisera against whole mouse serum and against mouse IgG. Evidently, adsorbed constituents of mouse serum are regular components of the T. musculi surface coat. After incubation in dilute whole mouse serum or in mouse IgG solutions, also the trypsinized cells were agglutinated by the 2 antisera. No such results were obtained with trypsinized cells incubated in serum-free buffers. It was concluded that mouse serum proteins were readily readsorbed on, and firmly bound to the trypsinized cells' surfaces. Specific agglutinations were obtained with trypsinized cells after incubation in dilute rat, rabbit, bovine, and human sera and in solutions of rat and rabbit IgG in reactions with the corresponding antisera. It seems, therefore, that the host serum proteins are adsorbed nonspecifically to the cell surface of trypsinized T. musculi bloodstream forms.When examined by electron microscopy, the intact trypomastigotes were covered by an ununiform, slightly granular, fibrillar extracellular coat, applied to the entire outer lamina of the pellicular and flagellar membranes. No indication of such a coat was noted in the trypsinized organisms. Flocculent surface coat-like matrix could, however, be discerned in cells which, after trypsinization, were incubated in various sera.

Notes: SYNOPSIS. Leptomonas pessoai from the reduviid hemipteron Zelus leucogrammus, was cloned. The original strain (ATCC 30252) and clones can differentiate from promastigote to opisthomastigote. Differentiation is faster at high temperature (37 C) and in a defined medium as compared with a complex medium. It is suggested that Leptomonas pessoai be designated Herpetomonas samuelpessoai.

Notes: Book reviewed in this article: Journal of Toxicology and Environmental Health. Vol. 1, no. 1, Sept. 1975. Hemisphere Publishing Corp.Maloine, S. A., ed. 1974. Diagnostique Immunologique des Parasitoses a Protozoaires et Helminthes.

Notes: SYNOPSIS. Haemogregarina bigemina was found in all Blennius pholis which exceeded 5.0 cm in length, but in none measuring less than 3.5 cm. No exoerythrocytic development was recorded. The first B. pholis eggs hatched in May while the first patent infections of H. bigemina occurred from September onward in metamorphosed fish. Consequently, if the life cycle of H. bigemina includes a vector, that organism is active between May and September at least. Circumstantial evidence indicates that the hematophagous isopod, Gnathia maxillaris and not leeches, could be a vector of H. bigemina. Developmental stages of sporozoa were found in a small number of the isopods which had fed on infected B. pholis but the parasites could not be identified as H. bigemina with certainty. Subcellular organization, typical of sporozoa, was recorded by electron microscopy of H. bigemina.

Notes: SYNOPSIS. Leptomonas pessoai promastigotes cultivated in a synthetic medium were agglutinated with concanavalin A (Con A). Agglutination was predominantly of the flagellar-flagellar type, and was inhibited with sucrose or α-methyl-D-mannoside.Cell surface polysaccharides and/or glycoproteins were demonstrated by several cytochemical methods at the fine-structural level. A Con A-horseradish peroxidase-diaminobenzidine (DAB) technic was used to detect Con A receptors in the pellicular membrane of the flagellar pocket region and in the flagellar membrane proper. Somewhat less of the Con A-DAB reaction product was observed in the pellicular membrane enclosing the rest of the cell.

Notes: SYNOPSIS. Phylogenetic relations are ultimately determined by homologous relationships, including both structural and functional data. Following the establishment of those relationships, the direction of evolutionary change must be determined using paleontologic, developmental, and especially morphocline, data. From that perspective the direction of subsequent development becomes clearer and the problems of origins become more explicit.Using the foregoing methodology it has been possible to identify plausibly monophyletic groups of animal protists or protozoa. Allowing for attendant difficulties, there nevertheless emerges certain fairly convincing generalities: (a) the predominantly pseudopodial forms, with a few minor exceptions, have direct origins from apochlorotic algae; (b) the predominantly kinetidal forms (zooflagellates and ciliates), though also derived originally from apochlorotic algae, give evidence of extended evolutionary development with the especially noteworthy emergence of a permanent ingestatory structure; (c) both groups have increased size, a tendency towards multinuclearity and polyploidy, cytoplasmic differentiations of various sorts, and complex life cycles.In terms of further evolution, namely the emergence of multicellular animals, the pseudopodial forms are almost certainly a dead end while the kinetidal forms are arguably the ancestors of at least 2 metazoan phyla.

Notes: SYNOPSIS. A clone of Cyclidium citrullus, adapted to growth at 18, 27, 37, 43, and 46 C had an optimum at 43 C, with 6.5 divisions/day. Transfer of cells previously grown at 43 or 46 C to 18 C resulted in death of most of the cells, transfer to 27 C increased the lag period, and transfer from 18 C to 37 or 46 C was followed faster division. All cells died at 48 C; some divided before death. At the temperatures employed maximum cell sizes (length and width) were achieved in the early log phase. At 43 C, however, the early log phase cells were smaller. Quantitative and qualitative differences in the free amino acids in the cells were found in ciliates grown at 18, 43, and 46 C; the highest amount/cell was found at 18 C, and the lowest at 43 C. High concentration of proline was noted only at 18 C.

Notes: SYNOPSIS. Additional information on host interactions with trypanosomatid membranes was obtained from studies of a monomorphic strain of Trypanosoma brucei harvested at peak parasitemia from intact and lethally irradiated rats. Pellets of trypanosomes were fixed briefly in glutaraldehyde and processed for thin section electron microscopy or freeze-cleave replicas. Observations of sectioned material facilitated orientation and comparison of details seen in replicas. Fracture faces of cell body and flagellar membranes as well as 3-dimensional views of the nuclear membrane were studied. Cell body membranes of 80% of the organisms from intact rats contained random arrays of intramembranous particles (IMP). Aggregated clusters of particles appeared on the fracture faces of 20% of the trypanosomes. Some of these membranes had nonrandomly distributed particles aligned in distinct rows on the outer fracture face of both cell body and flagellum. Many inner face fractures of the cell body membranes had a particle arrangement similar to the longitudinal alignment of cytoskeletal microtubules. No aggregated particle distribution was seen in membranes of trypanosomes harvested from lethally irradiated rats. Replicas of trypanosome pellets also had plasmanemes as a series of attached, empty, coated membrane vesicles. These structures were found in close association with, as well as widely separated from the parasites. The shedding of these vesicles and the variation of particles in cell body membranes are discussed in light of antibody-induced architectural and antigenic changes in surface properties of trypanosomatids.The convex face of the inner membrane of the nucleus also is covered with randomly arrayed particles. More IMP were observed on the inner than on the outer nuclear membranes. Images of nuclear pores were also seen. The importance of these structures in drug and developmental studies of trypanosomes is discussed.On fracture faces of the flagellar membrane there were miniature maculae adherentes, unique to the inner fracture face and occurring only at regions of membrane apposition between cell body and flagellum. Each cluster of particles exposed by the freeze-cleave method corresponds to an electron-dense plaque seen in thin section images. However, because of a unique fracture pattern, these plaques were not revealed on the apposing body membranes, as illustrated in thin sectioned organisms.

Notes: SYNOPSIS. Phytomonas davidi (Trypanosomatidae) originally discovered by Lafont in 1909 on the island of Mauritius was rediscovered in Euphorbia cyathophora in Florida. Successful cultures were established in diphasic medium consisting of duck blood agar and modified Phillips’medium as overlay. Optimal growth was obtained when Mansour's medium was used as overlay and poorest growth when Cowperthwaite's medium buffered at pH 5.0 was utilized for this purpose. Marked changes tending toward choanomastigotes rather than the elongate twisted promastigotes were observed in cultures.

Notes: SYNOPSIS. Past reports of Synophrya, the only apostome ciliate known to harm its host, indicated that it was restricted in its distribution and in the hosts it can infect. In recent collections of decapods from the off-shore waters of North Carolina and Georgia, 30% of all specimens were infected with Synophrya. Forty-four percent of all the species collected had individuals infected with Synophrya, and 63% of all the families collected contained species that had infected individuals. There is no obvious structural or phylogenetic relationship between these families that explain why they are infected. The presence of Synophrya may be related to salinity since decapods captured in estuaries were never infected and decapods captured close to shore were only rarely infected. The salinities of these waters range from 15–35%, but the salinity of the off-shore waters where the great majority of infected specimens was found ranges only from 35–36%.

Notes: Book reviewed in this article:Pirt, S. J. 1975. Principles of Microbe and Cell Cultivation.

Notes: SYNOPSIS. Plasmodium lophurae serine hydroxymethyltransferase (EC 2.1.2.1) was partially purified and characterized by (NH4)2SO4 fractionation and chromatography on Sephadex G-100. The enzyme, precipitated by 3.0–3.3 m (NH4)2SO4, had a molecular weight of 68,300 as estimated by exclusion chromatography on G-100. The pH optimum of the enzyme was 6.8–7.6 in sodium phosphate-citrate buffer. Citrate stabilized the enzyme during storage in phosphate buffer at 4 C. The Km was 4.3 × 10−3m for l-serine and 2.5 × 10−4m for tetrahydrofolate.

Notes: Book reviewed in this article:Cordero del Campillo, M. et al. 1975. Indice-Catalogo de Zooparasitos Ibéricos. I. Protozoos. II. Trematodos.

Notes: SYNOPSIS. Haemogregarina balli sp. n. is described from the blood and organs of the common snapping turtle Chelydra serpentina serpentina and from the gastric and intestinal ceca of the presumed invertebrate hosts, the leeches Placobdella parasitica and Placobdella ornata. In the peripheral blood of the turtle, male and female gametocytes and immature erythrocytic schizonts are found within erythrocytes. The maturation of erythrocytic schizonts containing 6–8 merozoites is recorded from liver imprints. Schizonts with 13–25 merozoites are found in various cells of the liver, lung and spleen. In the gastric ceca of the leeches the host erythrocytes are digested, releasing the gametocytes and immature erythrocytic schizonts. Immature erythrocytic schizonts degenerate. Association of the gametocytes occurs in the intestinal ceca. The microgametocyte apparently gives rise to 4 nonmotile microgametes, one of which fertilizes the macrogamete while the other remain as condensed, residual nuclei on the periphery of the developing oocyst. The oocyst increases in size with maturity. A mature oocyst produces 8 sporozoites from a single germinal center. Sporozoites liberated from the oocyst are found in the tissues of the leech. Transovarial transmission of the parasite does not occur in the turtle. Attempts at experimental transmission failed. Previously unfed (control) leeches were negative for the parasite. Haemogregarina balli is compared with other haemogregarines described from C. serpentina. Features of species of Haemogregarina and Hepatozoon as well as the taxonomy of these genera are discussed.

Notes: SYNOPSIS. In low viscosity media, Euglena gracilis strain Z responds to a sudden change in light intensity by a cessation of forward movement, followed by a reorientation of the locomotor flagellum which results in turning of the cell around the lateral axis (photophobic response). At a viscosity interface between low [∼ 1 cP (centipoise)] and high (4000 cP) media, the cells exhibit avoidance responses or become immobilized in the higher viscosity medium. Upon changing the light intensity, free swimming cells have photophobic responses, while immobilized ones undergo body contractions. For cells immersed in media of varying viscosity, the delay between light stimulation and body contraction (transduction time) is shortest at high viscosities. From 500 to 2000 cP, where the cells are capable of both movement and light-induced body contractions, there is a logarithmic dependence of the transduction time on the viscosity. The transduction time does not vary appreciably with the intensity of the primary light stimulus within a range of 0.14-1.13 kW/m2.

Notes: SYNOPSIS. Eight species representing 8 genera of gallinaceous birds were used: Alectoris graeca; Colinus virginianus; Coturnix coturnix; Gallus gallus; Meleagris gallopavo; Numidia meleagris; Pavo cristatus; Phasianus colchicus. Three-week-old birds were dosed with sporulated oocysts of Eimeria tenella Beltsville strain. At 4, 24, 48, 72, 96, 120, 144, and 168 hr after inoculation, 1-3 infected birds and uninoculated controls of each species were killed by cardiac exsanguination. Pieces of intestines were fixed and examined for stages of E. tenella as stained paraffin sections or indirect fluorescent antibody preparations. Oocyst counts were made in droppings collected for the first 6 days of the patent period. Sporozoites were found in the lamina propria of some birds of 5 species at 4 hr postinoculation, but no stages were found thereafter except in the breeds of G. gallus and A. graeca. At 144 and 168 hr postinoculation, a few macrogametes were found in the ceca of 2 A. graeca, but no oocysts were found in the feces. No statistical difference was found between the number of oocysts produced/bird in the breeds of G. gallus examined. It is evident from these observations that E. tenella did not complete its life cycle in several close phylogenetic relatives of G. gallus, even though in other studies this parasite was found to complete its life cycle in cell cultures derived from the same birds.

Notes: Book reviewed in this article:Faust, E. C., Beaver, P. C. & Jung, R. C. 1975. Animal Agents and Vectors of Human Disease.

Notes: Sorogena stoianovitchae is an unusual ciliated protozoan with a life cycle characterized by the aggregation of individual trophic cells to form a multicellular sorogen that rises from the liquid culture medium surface by the secretion of a stalk. The noncellular stalk is a tapered, longitudinally furrowed structure composed of a fibrillar matrix that is initially hydrated, but with time dehydrates, the stalk becoming thin and brittle. This dehydration is of importance from the earliest stages of stalk formation since it results in the formation of the outer sheath-like region of the stalk that appears to provide much of the support of the stalk. Cytochemical tests of the stalk for polysaccharides (including acidic mucopolysaccharides) and proteins are positive. Proteolytic enzymes degrade the stalk. Lectins specific for glucose and N-acetyl-D-glucosamine bind to the stalk. Gas chromatography analysis detected the presence of fucose, glucose, glucosamine, and arabinose, as well as a variety of amino acids, predominantly glycine. The cytochemical and biochemical tests, the ultrastructural data, and the behavior of the stalk material suggest that the staik is composed of a matrix of complex protein-polysaccharide molecules.

Notes: Nosema disstriae, a parasite of the forest tent caterpillar, Malacosoma disstria, was cultured with cell lines UMN-MDH-1 (Malacosoma disstria), IPLB-1075 (Heliothis zea), and BTC-32 (Triatoma infestans). Infected cultured cells were used to infect the healthy cell lines. Electron micrographs of thin sections of 6-day-old cultures revealed infected cells that exocytosed vesicles containing vegetative and immature sporulating forms of the parasite. Some of these forms were believed to be responsible for intercellular transmission of the parasite. The spread of infection was augmented by culturing the cells at high densities; if the density was too low, there was little or no cross infection. Cross infection was inhibited, but not blocked completely, by high osmolality of the culture medium. The yield of spores from a confluent cell monolayer at the end of growth was generally 1–4 × 107 per ml of culture medium.

Notes: The fine structure of the trophozoite of Acanthamoeba palestinensis with a special emphasis on the Golgi complex, microbodies, and mitochondria has been examined. Golgi complexes are distributed throughout the cytoplasm but are most abundant in the perinuclear region. Usually two Goigi complexes are found in the same plane on opposite sides of the nucleus. One of them appears to be in an intimate association with the nuclear membrane. The region of contact contains compact cisternae, vesicles of various sizes, as well as granular and amorphous electron-dense material. Structural changes in the nuclear envelope are also observed in this area. A structure consisting of a Golgi complex and electron-dense microtubule organizing center, comparable to the centrosphere of other Acanthamoeba species, has been observed. Microbodies, surrounded by a single unit membrane and containing a granular matrix and tubular inclusions, are scattered throughout the cytoplasm. These organelles, circular (∼1 μm in diameter) or ovoidal (∼1 μm in length and ∼0.5 μm in width) in section, have often an irregular outline. These microbodies are probably the morphological equivalent of peroxisomes and glyoxysomes. Most mitochondria show a typical structure including tubular cristae and intracristal inclusions. Occasionally mitochondria with two apposed double membranes running through the midline are found. Such atypical cristae have never been reported in small amoebae before.

Notes: Heavy infections with enigmatic mobile organisms have recently been found in the blood of carp (Cyprinus carpio) in Central Europe. The organisms measure up to 15 μm, are variable in shape, and exhibit an unceasing twitching or dancing movement. Their developmental cycle starts with a primary cell enclosing a secondary cell. The former grows while the latter produces inside itself by a series of binary fissions and internal cleavages up to eight secondary cells, each of which encloses an inner (tertiary) cell of its own. In addition, up to four tiny cells with compact nuclei (“residual bodies”) also result from divisions of the secondary cells. Primary cells containing the products of the division of secondary cells finally disintegrate, releasing the secondary cells, which in their turn become new primary cells and repeat the cycle all over again. The structure and behavior of these organisms were so incompatible with existing ideas on myxosporean development that their myxosporean affinity was at first unrecognized. The final proof of their identity–appearance of myxosporean spores in sterile, experimentally infected hosts–is still to be presented. The interpretation of the myxosporean features of their life cycle (i.e., [1] the pericyte nature of the primary cell, [2] proliferation by disintegration of the pseudoplasmodial primary cell, [3] no rigidly fixed pattern in vegetative development), their ultrastructure (i.e., [1] characteristic bundles of microtubules and numerous free ribosomes in secondary cells, [2] lack of centrioles, [3] membranes enclosing the secondary cells within the primary cells), and facts on their epizootiology (i.e., [1] no success at transmission via leeches, [2] the occurrence of these organisms along with Sphaerospora renicola Dykova and Lom) suggest that they are stages of S. renicola from the kidney of carp. Similar mobile organisms were found in the blood of fry of two other fishes (Gobio gobi and Tinca tinca) which are also hosts for a Sphaerospora that infects the kidney. This suggests that these organisms represent an early phase in the developmental cycle in the genus Sphaerospora. The existence of cells enveloped one within the other (secondary and tertiary cells) in the developmental cycle, a characteristic myxosporean feature itself, is an intriguing parallel to similarly enclosed cells in sporogenesis of Paramyxea (Ascetospora).

Notes: The morphology and morphogenesis of the kinetofragminophoran soil ciliates, Fuscheria terricola n. sp. and Spathidium muscorum Dragesco & Dragesco-Kerneis, 1979, are described. Stained specimens (protargol) are characterized biometrically. The new species differs from the other species of the genus in its body size, body shape, number of kineties, length of extrusomes, and habitat. Both species have telokinetal stomatogenesis, which commences with a proliferation of kinetosomes at those kineties which bear the brosse. Fuscheria terricola does not have a complex perioral ciliature; indeed, it might be that this species has only monokinetids. Thus only a proliferation of kinetosomes and the separation of the kineties takes place in the prospective division furrow. In contrast, S. muscorum differentiates short dikinetid kinetofragments in the region of the division furrow, which are arranged to form the perioral kinety of the opisthe in the intermediate and late stages of the stomatogenesis. The right part of the perioral kinety develops first. This and other studies show that telokinetal stomatogenesis proceeds very differently depending on the differentiation of the oral ciliature; however, detailed studies on the morphogenesis of kinetofragminophoran ciliates are still too few in number for subtypes to be defined.

Notes: The apicomplexan family Barrouxiidae Léger, 1911 is reviewed and revised on the basis of present information. It includes the genera Barrouxia Schneider, 1885 with ten named species, Defretinella Henneré, 1966 with one named species, and Goussia Labbé, 1896 with 25 named species. The family is characterized by having bivalved sporocysts with a longitudinal suture line. Available information, admittedly spotty, is given for each species on oocyst, sporocyst and sporozoite structure, and on locus of sporulation. The following seven new combinations are made: Goussia flaviviridis (Setna & Bana, 1935) n. comb. in the gecko Hemidactylus flaviviridis; G. hyalina (Léger, 1898) n. comb. in an unidentified aquatic beetle; G. lacazei (Labbé, 1895) n. comb. in the centipedes Lithobius forficatus and L. martini; G. metchnikovi (Laveran, 1897) n. comb. in the gobies Gobio gobio and G. albipinnatus; G. schaudinniana (Pinto, 1928) n. comb. in the centipede Lithobius forficatus; G. stankovitchi (Pinto, 1928) n. comb. in the small bleak Alburnus alburnus, the bream Abramis brama, and the red roach Scardinius erythrophthalmus; Goussia sp. (Dogel' Akhmerov, 1959) nov. comb. in the freshwater fish Gnathopogon chankaensis.

Notes: Comparison of the electrophoretic migration patterns of proteins of active 40S and 60S ribosomal subunits isolated from nine amicronucleate strains of Tetrahymena of known phenoset revealed strain dependent differences which correlated with the phenoset classification of these strains as determined by Borden, Whitt & Nanney, who compared isoenzyme patterns.

Notes: Chromatin from a uninucleate dinoflagellate, Crypthecodinium cohnii, a binucleate dinoflagellate, Peridinium balticum, and a chromophyte, Olisthodiscus luteus, was examined by nuclease digestion and the results were compared to those from vertebrates. Gel analysis of the products of staphylococcal (micrococcal) nuclease digestion revealed a DNA repeat unit of 220(±5) base pairs for O. luteus and 215(±5) for P. balticum. Limit digestion gave a core particle of 140 base pairs, revealing that these longer repeat sizes are due to longer linker regions. No repeating subunit structure was found upon electrophoresis of digests of C. cohnii nuclei. Examination of the DNA fragments produced by DNAse I digestion of nuclei isolated from P. balticum and O. luteus showed the same ladder of ten base multiples as seen in chromatin from other eukaryotes. Examination of the kinetics of digestion by DNAse II of Peridinium chromatin revealed less susceptibility when compared to DNAse I digestions while 70% of Olisthodiscus chromatin and 35% of C. cohnii chromatin was sensitive to DNAse II. These data, taken together with previous results from Euglena, indicate that while algal chromatin is similar to that of higher eukaryotes in regard to DNAse I and II action, it differs in that the linker DNA is longer. In addition, the Hl-like histone from O. luteus and P. balticum is located in the linker DNA as in higher eukaryotes.

Notes: Changes in mean cell size, DNA and cell density were monitored at 6-h intervals for 72 h in populations of six species (eight clones) of marine dinoflagellates to determine the temporal relationships between the cell cycle events of DNA replication and cytokinesis. Batch cultures were maintained at 15 or 20°C on a 12-h light: 12-h dark photoperiod. Cell densities and size frequency distributions were determined conductimetrically and the amount of DNA within populations was measured fluorometrically. A variety of intra- and interspecific relationships were observed, ranging from parallel phasing of cell cycle processes to variations which involved the temporal uncoupling of DNA synthesis from the phased pattern of cell division which is characteristic of dinoflagellate cell cycles. Daily growth rates of individual populations varied from 0.05 (Gymnodinium nelsoni) to 2.08 (Amphidinium carteri) cell divisions day-1 and DNA doubling rates ranged from 0 to 1.14 day-1. Mean doubling rates for DNA were usually 30–40% lower than those for cells. The degree of difference in these rates and the amount of variability evident in cell cycle sequences may be major factors in determining the rate and extent of development of dinoflagellate populations in nature.

Notes: In Aedes cantator, Amblyospora sp. is transovarially transmitted and has two developmental sequences. The life cycle is initiated in the adult female with the release of sporoplasms from binucleated spores not bounded by membranes, lying free within host oenocytes. Sporoplasms infect the developing oocytes and are transmitted to the filial generation when the eggs are laid. In some of the female progeny that hatch from infected eggs, diplokaryotic cells infect host oenocytes and divide by binary fission during merogony. Sporulation and spore formation do not occur until a blood meal is taken by the host and they coincide with the development and maturation of the oocytes to complete the cycle. In other female and all male progeny, pathogen development occurs within fat body tissue of the host where diplokaryotic cells divide by multiple fission during merogony to spread the infection. Sporulation in this developmental sequence is characterized by the secretion of an accessory membrane and the meiotic division of diplokaryotic sporonts, which result in the formation of octonucleated plasmodia that undergo cytokinesis to form eight haploid spores which are not perorally infectious to other mosquito larvae. There is no increase in the prevalence of either type of infection in field populations during juvenile development, indicating that there is no direct horizontal transmission of the pathogen within any one generation. Data obtained from laboratory rearings of infected progeny, however, show that infections cannot persist relying solely upon maternal-mediated transmission and that some other mode of transmission must be operative for continued maintenance of this microsporidium in A. cantator.

Notes: Cells of Amoeba proteus and Chaos carolinensis that were in the process of phagocytosing large prey organisms were studied to find a structural basis for the generation of mechanical forces exerted by newly forming food cups. It was found that the food-cup walls facing prey organisms have a more prominent network of thin filaments inside the plasmalemma and that the glycocalyx covering the area is more condensed than usual.

Notes: Monoclonal IgG antibodies against sporozoites of Eimeria tenella were obtained from the ascites fluid of BALB/c mice. Oocysts, sporocysts, and sporozoites were exposed to medium 199, normal ascites fluid, or monoclonal antibodies 1A, 9D, 3D3II, or 2G8f. Specimens were then incubated with ferritin-conjugated goat anti-mouse IgG antibody. Ferritin was uniformly distributed over the surface of sporozoites exposed to 1A, 9D, or 3D3II; ferritin was localized in patches on sporozoites exposed to 2G8f. A uniform layer of ferritin was present on the inner layer of oocyst walls and on the Stieda body and outer surface of sporocysts exposed to 1A, 9D or 3D3II. In specimens treated with 2G8f, ferritin was present on the inner layer of the oocyst wall and the Stieda body, but not on the sporocyst wall. No ferritin was found on specimens exposed to medium 199 or normal ascites fluid. Monoclonal antibodies 1A, 9D, and 3D3II, but not 2G8f, caused complement-mediated lysis of sporozoites. These findings indicate that oocysts, sporocysts, and sporozoites of E. tenella contain common antigens specific for each monoclonal antibody tested.

Notes: Several divalent cation-dependent ATP phosphohydrolases associated with cilia, ciliary axonemes, ciliary membranes, pellicles, trichocysts, nuclei, mitochondria, microsomes, and soluble peripheral cell surface fractions of Paramecium tetraurelia were resolved in this study. Fifteen different activity bands were detected in whole cell sonicates or subcellular fractions by Triton polyacrylamide gel electrophoresis and ATPase activity staining. The ciliary surface membrane contained two major ATPase activities that were distinct from the enzymes associated with all other cell fractions.

Notes: During feeding a peritrophic membrane (PM) is formed in the gut of the tick Ixodes dammini, dividing the lumen of the gut into an ecto- and endoperitrophic space. Babesia and all food particles ingested with the blood meal by the tick are retained in the endoperitrophic space, the lumen proper. Only Babesia equipped with a highly specialized organelle, the arrowhead, are able to pass the PM and enter the ectoperitrophic compartment. During the crossing of the PM the arrowhead loses its density, suggesting that enzymes released from it dissolve the polymers in the PM, making passage of the parasite through this barrier possible. In the ectoperitrophic space the arrowhead of Babesia touches the epithelial cell. At the point of contact the membrane of the host cell starts to invaginate, and simultaneously the arrowhead's fine structure loses its highly organized pattern. The growing host membrane encircles the parasite and the arrowhead diminishes progressively in size. When the piroplasm is inside the host cell, the arrowhead can no longer be found. During invasion the host membrane often touches the parasite's plasma membrane at the site of a coiled structure, and the host membrane becomes ruptured and the nearby host cytoplasm appears to be lysed. Babesia inside the host cell is covered solely by its own plasma membrane; the invaginated host membrane is missing. It is postulated that the latter disintegrates during invasion by the parasite through the action of enzymes from the coiled structure. The parasite is surrounded by a halo of homogeneous material deriving most probably from the lysed host cytoplasm.

Notes: A technique for the separation of schizonts of Plasmodium falciparum is described. The different stages of the asexual cell cycle of the parasite were positioned according to their density in a continuous gradient of Percoll. Young trophozoites coincided with erythrocytes in a broad band corresponding to densities from 1.075 to 1.100 g/ml, whereas schizonts were concentrated at a density approximating 1.062 g/ml. The viability of the parasites was unimpaired by this procedure. Young trophozoites and schizonts continued their normal life cycle when cultured after the separation procedure. The percentage of recovery was high, reaching 80% of the initial quantity. Possible applications of the technique are discussed.

Notes: Chemically defined minimal media for the cultivation of high temperature tolerant and pathogenic Naegleria spp. have been developed. A defined minimal medium, identical for N. fowleri and N. lovaniensis, consists of eleven amino acids (arginine, glycine, histidine, isoleucine, leucine, methionine, phenylalanine, proline, threonine, tryptophan, and valine), six vitamins (biotin, folic acid, hemin, pyridoxal, riboflavin, and thiamine), guanosine, glucose, salts, and metals. Three of the four strains of Naegleria fowleri tested (ATCCr̀30100, ATCCr̀30863, and ATCCr̀30896) and two strains of N. lovaniensis (ATCCr̀30467 and ATCCr̀30569) could be cultured beyond ten subcultures on this medium. For N. fowleri ATCCr̀30894 diaminopimelic acid, or lysine, or glutamic acid was also required. Mean generation time was reduced and population density increased for all strains with the introduction of glutamic acid. Glucose could be eliminated from the minimal medium only if glutamic acid was present. Without glucose, mean generation time increased and population density decreased. Diaminopimelic acid could substitute for lysine for ATCCr̀30894, indicating that Naegleria species may synthesize their lysine via the DAP pathway. Naegleria fowleri ATCCr̀30100 could be adapted to grow without serine or glycine in the minimal medium with glutamic acid added, but with mean generation time increased and population density decreased. The strain could be grown in the minimal medium in the absence of metals. For growth of N. australiensis ATCCr̀30958, modification of the medium by increasing metals ten-fold, substituting guanine for guanosine and adding lysine, glutamic acid, and six vitamins (p-aminobenzoic acid, choline chloride, inositol, vitamin B12, nicotinamide, and Ca pantothenate) was required.

Notes: From several surveys of environmental sites, the virulent human pathogen, Naegleria fowleri, was isolated from a pond in Georgia, a sewage treatment plant in Missouri, and from the Potomac and Anacostia rivers near and in Washington, D.C. Widely scattered, sparse populations seemed only a potential threat to human health at the time of sampling. The data support an estimate that the sites sampled contain 10,000 typical, low temperature, bactivorous amoebae for each heat tolerant amoeba able to grow at 45° C. Heat tolerant competitors were much more common than N. fowleri. Naegleria lovaniensis, which is heat tolerant but nonpathogenic, was isolated from and downstream from an open air thermal pollution temperature gradient. Hot piles of composting sewage sludge yielded no amoeboflagellates, many heat tolerant (45–49° C) amoebae, and one thermophilic (52° C) Acanthamoeba. Features of the methods used include two-stage incubation to increase isolation of sparse organisms and distinction of N. fowleri from almost all other amoebae on agar plates. The flagellate-empty habitat hypothesis postulates a general model in which human intervention and/ or natural events remove usual competitors and the ability to transform to a motile flagellate confers an advantage in recolonizing.

Notes: The ultrastructure of the bloodstream form of Cryptobia salmositica in rainbow trout was examined during the acute phase of experimental infection. The arrangement of the major groupings of cytoplasmic microtubules originating near the basal bodies is similar to that in other bodonids. The cytostome is reinforced both by pellicular microtubules and an electron-dense plaque. Certain microtubules associated with the flagellar pocket serve as nucleating sites for pellicular microtubules. A flagellar rootlet, consisting of two parallel fibers which are bound together intermittently by electron-dense plaques, curves posteriorly from the basal body of the recurrent flagellum towards the kinetoplast. The basal body associated plaque on the kinetoplast membranes is duplicated at the same time as the basal bodies. Cytoplasmic microtubules are found in association with the plaque and the outer kinetoplastic membrane. A pulsatile vacuole, described for the first time in a hemoparasitic cryptobiid, lies adjacent to the post-flagellar pit. Smaller, interconnected vesicles of the spongiome are continuous with the pulsatile vacuole. Since a pulsatile vacuole occurs not only in free-living and ectoparasitic cryptobiids but in the hemoparasitic (=trypanoplasm) forms as well, this is no longer a character by which the genus Trypanoplasma may be separated from the genus Cryptobia. Possession of this osmoregulatory complex may allow the organism to survive outside of a host and fulfill a monoxenous life cycle, in addition to the usual heteroxenous cycle involving a leech as vector.

Notes: The life-cycle of the amoeboflagellate Tetramitus rostratus includes amoeboid, cyst, and flagellate stages. The ultrastructure of these three stages is illustrated, with particular emphasis on flagellate morphology. Amoeba morphology is typical of that of limax amoebas. Cysts, forming from trophic amoebas, are enclosed by a wall made up of two layers: ectocyst (ca. 70 nm), and endocyst (200 nm). The wall apparently forms from precursor material present in vesicles in the pre-cyst stage cytoplasm. Flagellate morphology is characterized by a well-defined top-shaped profile, maintained by microtubules under the plasma membrane. The flagellar apparatus or mastigont consists of four flagella, their basal bodies, sheaves of microtubules associated with two of the basal bodies, and several rhizoplasts (periodicity 20 nm). A deep, microtubule-supported, ventral invagination appears to function as a gullet. A small number of mitotic stages observed in amoeboid and flagellate individuals suggests similarity in the division process in both stages: intranuclear mitotic apparatus, nucleolus persisting through mitosis, no centrioles or basal bodies functioning as centrioles, difficulty in resolving chromosomes. The text compares ultrastructures of several amoeboflagellate organisms and evaluates the phylogenetic significance of those features common to different species. On the basis of this study, Tetramitus most closely resembles Naegleria spp.

Notes: The hypothesis is advanced that all freshwater Euplotes species with a 9 type 1 fronto-ventral cirrus pattern (E. patella type) depend upon bacteria-like endosymbionts. Aposymbiotic cells of these species are unable to divide. The hypothesis is based on the investigation of 40 different freshwater Euplotes stocks collected in Germany, France, the USA, and Japan. No symbionts were found in E. crenosus and E. palustris, freshwater species with 10 fronto-ventral cirri, nor in E. muscicola, a representative of the freshwater Euplotes group with a 9 type 2 fronto-ventral cirrus pattern (E. affinis type). Characteristic for the essential endosymbionts are multiple nucleoids, a feature described earlier for omikron, an indispensable symbiont of E. aediculatus. Although the symbionts differ from omikron and among each other in size, shape, and their average number per host, they are believed to be related to omikron. In two stocks a different type of bacterium was found in which no defined nucleoids can be detected. Transfer of this symbiont into aposymbiotic cells, originally carrying omikron, revealed that it can restore the ability to multiply. Similarly, omikron was also able to restore the ability to divide in cells freed of this symbiont. It is assumed that this different type of symbiont is a secondary invader of Euplotes which displaced the original omikron-like endosymbiont. Some of the stocks were found to carry, in addition to omikron-like symbionts, other symbiotic bacteria; E. daidaleos carries in addition an alga. The findings suggest that the freshwater Euplotes species with a 9 type 1 cirrus pattern are closely related to each other and evolved from an ancestor (probably of cirrotype 10) which already was dependent upon endosymbionts of the omikron type. It supports the view that the two subgroups of freshwater Euplotes forms with a cirrotype of 9 have evolved independently from each other from species with 10 fronto-ventral cirri by losing a cirrus at different positions.

Notes: Promastigotes of Leishmania mexicana mexicana attach to mouse macrophages in vitro in the absence of serum by a wheat germ agglutinin-like ligand on the surface of the promastigote that binds to the N-acetyl glucosamine moiety of a receptor on the surface of the macrophage. The binding is temperature dependent, and the macrophage receptor is trypsin, cytochalasin B, and glutaraldehyde sensitive. The promastigote ligand is proteolytic enzyme and glutaraldehyde insensitive. Uptake follows attachment and is assisted or inhibited as for attachment. Treatment of promastigotes with proteolytic enzymes uncovers a receptor for a serum component that binds strongly to a mouse macrophage receptor in vitro. The strain of mice donating the macrophages had little effect upon attachment and uptake except that A strain mouse macrophages attached fewer promastigotes in 10 min than those of outbred mice, but took up as many promastigotes over 90 min as those of outbred mice. Low responder Biozzi mouse macrophages took up more promastigotes than high responder Biozzi mouse macrophages. Normal unheated human, rabbit, and guinea pig sera lysed promastigotes and so inhibited their attachment to macrophages in vitro. Unheated immune serum showed an enhanced inhibition of attachment. Heated normal serum allowed attachment and uptake, while promastigotes treated with heated immune serum showed enhanced attachment to and uptake by macrophages. Treatment of macrophages in vitro with immune serum enhanced their ability to attach promastigotes and to engulf them. Repeated 90-min exposures of a population of promastigotes to uptake by mouse macrophages in vitro did not deplete the population of any sub-population more likely to be taken by macrophages. The first sub-population to be taken up survived better in macrophages over 24 h than subsequently engulfed sub-populations.

Notes: BALB/c mice were hyperimmunized with non-infectious extracts of either Leishmania braziliensis promastigotes or Trypanosoma cruzi epimastigotes. When spleen cells from these mice were fused with P3X63Ag8 plasmacytoma cells, the resultant hybridomas synthesized monoclonal antibodies which displayed specific reactivity by indirect immunofluorescence with distinct subcellular components of the parasites. These studies revealed that antigens associated with the flagellum and with a nongranular component of the cytoplasm would account for much of the serologic cross-reactivity observed between the two species. Conversely, antigens associated with surface and/or cytoplasmic granules and with an intracellular organelle believed to be the kinetoplast appeared to be species-specific.

Notes: The invasion of liver parenchymal cells by sporozoites of Plasmodium berghei Vincke & Lips, 1948, was studied in vivo using transmission electron microscopy. Livers of Brown Norway rats were examined 30 and 60 min after intraportal injection of 15 million sporozoites each. Sporozoites found after incorporation into vacuoles in hepatocytes were often located near a bile canaliculus at the lateral cell surface, surrounded by hepatocyte lysosomal structures; however, degradation of sporozoites caused by lysosomal digestion inside hepatocytes was never observed. Due to the crescent shape of sporozoites, serial sections were necessary to demonstrate the actual process of invasion of the hepatocyte. The hepatocyte's plasmalemma appeared to invaginate due to the sporozoite's action, thereby creating a parasitophorous vacuole. It was suggested that the sporozoite actively penetrated the hepatocyte; however, no visible depletion of rhoptries and micronemes was observed.

Notes: The human pathogenic amoeboflagellate Naegleria fowleri and the nonpathogenic species N. gruberi can be cultivated axenically but usually in different media. Naegleria fowleri 6088 has been adapted to grow in Balamuth H-4 medium, usually used to propagate N. gruberi nB81. and nB81 has been adapted to grow in supplemented Nelson's medium, usually used to propagate N. fowleri. N. gruberi nB81. grown in either medium, enflagellated 135 to 150 min after subculture to non-nutrient amoeba saline, whereas 6088 required 225 min. Naegleria gruberi nB81 grown in either medium was agglutinated by 100 ug concanavalin A/ml, whereas N. fowleri 6088 was not. Naegleria fowleri and N. gruberi grown in Nelson's medium became rounded to a greater extent upon chilling at 5° C and remained rounded longer than Naegleria grown in Balamuth medium. The specificity of the surface antigens was an inherent characteristic of each species and not dependent upon the propagating medium. but Naegleria grown in Nelson's medium was agglutinated more reproducibly and more effectively by antiserum. N. gruberi was somewhat more resistant to acriflavine, actinomycin D, cycloheximide, or tetracycline than N. fowleri, regardless of the culture medium. Naegleria fowleri 6088 grown in Nelson's medium, however, was more resistant to actinomycin D, daunomycin. mithramycin. sulfamethoxazole, or tyrocidine than 6088 grown in Balamuth medium. There are limitations on the validity of comparisons of N. fowleri and N. gruberi based upon cultures grown in different media.

Notes: Fine structural studies of the hydrogenosomes of Tritrichomonas foetus using an improved fixative reveal that they are enclosed by two closely apposed 6 nm membranes, which separate at some regions forming a large intramembranous vacuole where Ca++-binding sites are located. Fixation of the cells in a glutaraldehyde solution containing 5 mM CaCl2 and postfixation in an osmium tetroxide-potassium ferrocyanide solution led to the appearance of a reaction product associated with certain regions of the membrane of the hydrogenosomes and in the cisternae of the endoplasmic reticulum, in the recurrent flagellum, and in the plasma membrane. Treatment of ultrathin sections with EGTA removed the reaction product. These results, in association with others previously described, indicate the existence of several similarities between the hydrogenosomes and the mitochondria.

Notes: . One hundred eighty-eight stocks of Paramecium primaurelia. P. biaurelia, P. tetraurelia. and P. octaurelia were grown axenically and screened for variation in four different esterases and acid phosphatase using starch gel electrophoresis. Major observations: frequency of intraspecies variation for these enzymes is much lower in these four species than in other organisms; hypervariability for two esterases occurs in P. biaurelia both in isolates from worldwide locales and in a restricted locale; clustering of variations occurs in a high proportion of variant stocks in all four species; frequency of intraspecies variation is highest in Central and South America for all four species; and geographical differentiation is lacking between stocks in the same species both for common as well as variant phenotypes despite the cosmopolitan distribution of these species. These results are not correlated with adaptations that favor inbreeding over outbreeding. nor is the possession of bacterial endosymbionts strongly correlated with enzyme variation. When the riequency of intraspecies variation was examined for the aurelia complex of species as a whole for 13 enzymes, mitochondrial DNA, and ribosomal DNA, differences between enzymes in frequency of variation could be seen, ranging from less than 2% for seven enzymes to 12.4% for glucosephosphate isomerase, a value similar to that observed for malic dehydrogenase, mitochondrial DNA, and ribosomal DNA in P. tetraurelia. The percentage of polymorphic enzyme loci in the complex as a whole was found to be much lower than that observed for other organisms. For the species more intensely studied in this paper the level of genetic polymorphism was also much lower, although P. biaurelia showed greater variability for two of the enzymes.

Notes: . Strains of Tetrahymena thermophila were examined in an attempt to establish what role certain ions (Na+, K+, Li+, Ba++, Ca++, Mg++, Mn++, Al+++, Fe+++) play in influencing cell survival time in a culture medium. In short-term experiments (20–30 min), cell survival time in a 1% peptone medium is directly related to the valence of the ion employed. Long-term observations (lasting up to five days) in a 1% peptone medium containing lower ion concentrations revealed that the effects on cell-cycle time are not correlated with the valence state of the ion. Comparisons were made among the ionic resistances of strains of T. thermophila, of T. pyriformis sensu stricto, and of two subspecies of T. pigmentosa. Strains within a species are highly correlated in their patterns of ionic response, while marked differences between species occur. The most distinctive group of strains examined came from one of the subspecies (syngen 6) of T. pigmentosa.

Notes: . A two-stage chemostat modified to accommodate the growth of adhesive organisms was used to determine the yield constant, Y, of a representative soil amoeba, Acanthamoeba polyphaga, utilizing as its prey Pseudomonas paucimobilis. The first stage consisted of a glucose-limited bacterial culture in steady state. The second stage consisted of a simplified predator-prey system, nongrowing bacteria serving as the limiting substrate for amoebae. A refined methodology to more accurately determine Y was developed, and Y for Acanthamoeba polyphaga in batch and continuous culture was determined to be 19.1%.

Notes: . The swiftness of thermotaxis of Paramecium caudatum has been investigated for various populations of organisms by measuring the transient spatial distribution of the gathering process of organisms that are transferred to a temperature-gradient cell from the culture medium. The dispersion obtained from the spatial distribution for each population is found to decrease linearly with time and finally reach a steady state value. The gathering rate determined by the slope of the dispersion strongly depends on population; it increases with population.

Notes: . Blastocystis hominis, an anaerobic intestinal protozoan parasite of man, has a generation time (GT) in axenic culture of 8.5–19.4 h, depending on the strain tested. Average GT of the eight strains was 11.7 h. Zero growth time cell counts of 5.0 × 105/ml to 2.0 × 106/ml rose in 3–5 days to 1 × 107 or 1 × 108 cells/ml. The GT was determined for the 24-h period during which the most rapid growth occurred; about 2% of the B. hominis cells were in division during this time. Division under the culture conditions provided was by binary fission, the usual mode for B. hominis in vitro as well as in vivo. Division times were determined also by direct observation of individual dividing cells in slide cultures. These were usually ca. 40–60 min but sometimes as low as 20 min.

Notes: In contrast to the situation in 13 other species of the Tetrahymena pyriformis complex, in which the condensed degenerating old macronucleus lies in the posterior end of the cell during the late stages of conjugation, in Tetrahymena tropicalis that nucleus is found in the anterior portion. This developmental characteristic may be useful for taxonomic purposes as well as being of value in investigations on nucleocytoplasmic interaction.

Notes: Eimeria nuttalli oocysts were found in 58% (21/36) and E. procyonis oocysts in 25% (9/36) of raccoons Procyon lotor in Illinois, and sporocysts of Sarcocystis sp. in 17% (2/12) of other raccoons in Illinois. The oocysts of E. nuttalli were ellipsoidal to ovoid. 15–21 × 12–17 μm, with a one-layered, smooth, colorless wall. The oocysts of E. procyonis were 22–28 × 18–22 μm, with a rough, striated, brownish, two-layered wall. The sporulated sporocysts of Sarcocystis sp. were 11–13 × 8–10 μm. Attempts to infect baby pigs by feeding them sporocysts of Sarcocystis sp. from the raccoon failed.

Notes: Comments are made concerning the work reported at this Conference by Dr. Edith Box. The importance of stress on the animals used in experimental work is emphasized. Difficulties in identification of isosporan species in birds are mentioned.

Notes: A trypanosomatid flagellate, Leptomonas sp., develops and multiplies in the macronucleus (only) of natural and laboratory-reared populations of the ciliate Euplotes. Up to 90% of the natural populations of Euplotes in our test pond had such nuclear infections. Laboratory infections were transmitted to this ciliate by feeding it liberated parasites. Paramecium resisted infections. All laboratory-induced infections were lethal to Euplotes, while control clones of the uninfected ciliates remained viable. This leptomonad, unlike Leptomonas karyophilus (found in Paramecium), shows no leishmanial forms in its several ciliate hosts and shows a varied pattern of locomotion.

Notes: Some generalizations of a decade ago are reexamined in light of modern advances in coccidiology. Perhaps surprisingly, not many modifications need or can yet be made. Future successes of significance will be in areas of immunology and chemical genetics.

Notes: Stocks of the Tetrahymena pyriformis complex have been collected in North America and their mating reactivity has been studied. In addition to stocks mating with Tetrahymena americanis, T. borealis, T. pigmentosa, T. hyperangularis, and T. australis, stocks belonging to old syngen 5 and three new mating groups, numbers 13, 14, and 15, were discovered. Syngen 5 and groups 13 and 14 are distinct “biological” species, based on their reproductive isolation from other groups and on the ability of withingroup crosses to produce immature progeny. These species have been named T. hegewischi n. sp., T. sonneborni n. sp., and T. nipissingi n. sp., respectively. The cross between the two group 15 stocks did not produce immature progeny, and there is not sufficient evidence to conclude that this pair of stocks represents a separate species. Temperature tolerance measurements have been made on stocks representing all known micronucleate members of “pyriformis” complex. Within each species, the range of temperature tolerances is narrow; the average within-species standard deviation is 0.63°C. The species averages range from 32.7 to 40.7°C. Using syngen numbers, the order from lowest to highest temperature tolerance is 9, 8, 10, 7, 6, 4, 13, 14, 12, 11, 5, 3, 2, 1. The large differences among species make temperature tolerance a useful aid in identification, but the origins of the differences among species are unknown.

Notes: Members of the family Sarcocystidae, as defined by Frenkel, have had a complicated history, principally due to the existence of both coccidial and cystic stages. This formerly clandestine relationship resulted in dual or partial designations of nomenclature for individual species. The problem was further compounded by the obligatory heteroxeny of several of the genera, making it impossible to transmit the parasites from one individual to another of a single host. As a result, oocysts similar in appearance, though from hosts separated taxonomically up to the familial level, were sometimes considered to be identical. Discoveries within the last decade have generated much interest and some understanding. Current studies of these and other coccidia should emphasize complete cyclical transmissions with cognizance of potential heteroxeny with the production of tissue cysts in intermediate hosts.

Notes: Book reviews in this article: Ecology and Parasitology. Alexander, M., ed. 1980. Advances in Microbial Ecology Smith, H. G. 1978. The Distribution and Ecology of Terrestrial Protozoa of Sub-Antarctic and Maritime Antarctic Islands Taylor, Angela E. R. & Muller, R., eds. 1980. Vaccines Against Parasites Kreier, Julius P., ed. 1980. Malaria New Textbook of Protozoology Farmer, John N. 1980. The Protozoa: Introduction to Protozoology Phytoflagellates and Serial Endosymbiosis Theory Cox, Elenor R., ed. Phytoflagellates Tappan, Helen. 1980. The Paleobiology of Plant Protists. Margulis, Lynn. 1981. Symbiosis in Cell Evolution: Life and Its Environment on the Early Earth. Intercellular Communication and Nuclear-Cytoplasmic Interactions O'Day, Danton H. & Horgen, Paul A., eds. 1981. Sexual Interactions in Eukaryotic Microbes Whitson, Gary L., ed. 1980. Nuclear-Cytoplasmic Interactions in the Cell Cycle. Invertebrate Texts Alexander, R. McNeill. 1979. The Invertebrates Barnes, Robert D. 1980. Invertebrate Zoology Engemann, Joseph G. & (the late) Hegner, Robert W. 1981 Invertebrate Zoology ATCC Catalogue of Strains Hatt, Harold D., ed. 1980. The American Type Culture Collection: Catalogue of Strains I.

Notes: Polyamines are multiply amine-substituted straight-chain aliphatics; their content in different tissues may vary widely, and their functions are many. Their main routes of biosynthesis originate from ornithine and methionine. Polyamine content and biosynthesis in tryposomatid flagellates are reviewed concluding with emphasis on their possible role as critical drug targets in these parasitic protozoa so pathogenic for man in large areas of the world.

Notes: During spring and autumn, the total number of amoebae and the number of Acanthamoeba species able to grow at 37°C were determined in six thermally polluted factory discharges and the surrounding surface waters. The isolated Acanthamoeba strains were studied for growth in axenic medium, cytopathic effect in Vero cell cultures, and virulence in mice. Although more amoebae were isolated in autumn, the number of Acanthamoeba species was lower than in spring, when the percent of pathogenic strains among the isolates was highest. Higher concentrations of amoebae were found in warm discharges, and more virulent strains occurred in thermal discharges than in surface waters.

Notes: Eight species of loricate choanoflagellates (Acanthoecidae), Acanthoecopsis spiculifera Norris, Bicosta antennigera Moestrup, Bicosta spinifera Throndsen, Calliacantha multispina Manton & Oates, Calliacantha simplex Manton & Oates, Crinolina aperta Leadbeater, Diaphanoeca multiannulata n. sp., and Parvicorbicula socialis (Meunier) Deflandre, have been observed, by light and electron microscopy, in samples obtained from the Weddell Sea during the austral summer of 1977. Diaphanoeca multiannulata is described for the first time from these samples: the other organisms are discussed. The distribution of most species within the Weddell Sea was widespread. Habitats in which choanoflagellates were found included the water column, the edge of (or ponds on) ice floes, and the interior of ice floes. The distributional, environmental, habitat, and/or morphological range of all previously described species is expanded. Methods of variation of transverse costal diameters between genera may be potentially useful to the understanding of taxonomy and phylogeny of this family.

Notes: RESUME. L' étude ultrastructurale de la grégarine Gregarina blaberae a été entreprise après mise au point d'un protocole d'infestation expérimentale de larves vierges de Blattes, Blaberus craniifer. Les observations en microscopie électronique, effectuées en fonction du temps, ont permis de suivre le développement du sporozoïte, ainsi que la croissance et l' évolution du trophozoïte.La croissance est spectaculaire puisqu'en 18 jours elle entraîne la transformation du germe infectieux ou sporozoïte (L = 15 μm, φ=1 μm) en un céphalin—trophozoïte fixéà l' épithélium intestinal—de 250 μm de longueur pour un diamètre de 65 μm. L'organisation ultrastructurale du sporozoïte ne diffère pas de celle de la plupart des sporozoïtes des autres sporozoaires étudiés jusqu' à présent, le conoïde et les corps denses sont présents. La paroi est trimembranaire. toutefois le complexe membranaire interne présente quelques interruptions. Les premiers dictyosomes s' élaborent à partir de l'enveloppe nucléaire. La migration du noyau et des corps denses, puis la régression de toutes les formations caractéristiques du sporozoïte et l' établissement d'une zone corticale venant coiffer l' épimérite, ont lieu dans les 48 heures suivant l'infestation et marquent la transformation sporozoïte-céphalin.L' évolution du céphalin, se poursuit par la formation des ébauches des plis épicytaires qui s'effectue à partir du 3éme jour du développement à la base du deutomérite. Un système régulier de plis longitudinaux ou épicyte s' établit ainsi sur toute la partie extra-cellulaire de la grégarine. Dès les 4éme-5éme jours de développement, un réseau vacuolaire et un chondriome important se différencient dans l' épimérite, tandis qu'un septum de nature fibrillaire isole le protomérite du deutomérite. Le stade suivant—à partir du 6éme jour—est marqué par une ségrégation du matériel glucidique au niveau de ces 2 segments.Le modèle étudié permet de préciser le rôle de l' épimérite dansla nutrition du parasite, l' évolution du chondriome et des membranes corticales au cours de la phase de croissance végétative des grégarines polycystidées.

Notes: SYNOPSIS. Stomatogenesis was studied in the heterotrich ciliate Blepharisma japonicum stained with protargol. During binary fission not only is a new oral apparatus made for the posterior daughter, but the already existing oral apparatus of the parent cell is reorganized, i.e. partially disassembled and then subsequently reassembled to provide a functional feeding apparatus for the anterior daughter cell. These morphogenetic events, requiring 21/2 to 3 hr, are complete by the time the anterior and posterior daughters separate.In preparation for division, an oral anlage is formed by the rapid proliferation of kinetosomes along 4–5 stomatogenic kinetics directly subtending the cytostome. This field of randomly oriented kinetosomes ultimately gives rise to the feeding apparatus of the posterior daughter cell. Early in division, the oral anlage separates into 2 longitudinal fields of kinetosomes: one is destined to give rise to the undulating membrane and the other forms the adoral zone of membranelles. Shortly after the anlage is established posterior to the cytostome, reorganization of the existing functional mouth is initiated. The morphologic changes associated with this dedifferentiation-redifferentiation sequence lead to the formation of an oral apparatus for the anterior daughter and cannot be distinguished from those characteristically seen during physiologic reorganization.

Notes: SYNOPSIS. The effects of age and sex of the cat on oocyst shedding, multiplication of Toxoplasma gondii in tissues of cats, and acquisition of immunity were investigated after oral inoculation of cats with Toxoplasma cysts. Twenty-five cats varying in age from 1 week to 39 months were killed 7-97 days after inoculation with T. gondii. Homogenates of brain, heart, mesenteric lymph nodes, retina, and blood from these cats were inoculated into mice to test for Toxoplasma infectivity. Toxoplasma was isolated more frequently and in higher titers in mice receiving inocula from cats of the youngest age group (1 week old). Toxoplasma gondii was isolated from tissues of only 2 of 21 cats older than 2 months (at the time of inoculation), although all of the animals shed oocysts within 1 week after ingesting the parasites.The number of oocysts shed varied among littermates of the same sex and between sexes. Generally, cats younger than 12 months shed more oocysts than older cats. The number of oocysts shed by older cats varied considerably; males generally shed more oocysts than the females. However, the numbers of cats examined were too small for statistical comparison. Nevertheless, the observations suggest that cats older than 12 months should not be used in experiments where numbers of oocysts shed is critical.