ALBERT

Notizen: SYNOPSIS. Two main kinds of morphogenetic events occur among protozoa: (1) reproduction; (2) processes of reorganization, including encystment, excystment, sexual processes, structural and physiological adaptations exhibited in the course of complex life cycles, and restorative events elicited by environmental stimuli. Examples of such events are discussed with reference both to their own intrinsic interest and to their value in the study of cellular differentiation in general. Stomatogenesis in ciliates provides a remarkable instance of extensive and rapid differentiation. The phenomenon may be studied to advantage not only in reproduction but also in the macrostome-microstome transformation. Other simple transformations in protozoa providing unparalleled material for experiments on cytodifferentiation under controlled conditions are excystment and encystment, the amebo-flagellate transformation, and the leishmania-leptomonad change. The more complex transformations occurring in the life cycles of trypanosomes and in the appearance of sex under the influence of an insect hormone provide additional material of basic significance to an understanding of differentiation.

Notizen: SYNOPSIS. Euglena gracilis strain Z rendered permanently apochlorotic by several chemical and physical agents contains bodies similar in size to normal plastids. Some of these bodies contain lamella-like structures; others contain crista-like structures. The lamella- and crista-like structures are made up of 2 electron-dense layers separated by an electron-lucent layer.These structures are compared to normal lamellae and it is suggested that apochlorotic cells contain lamellae that lack the thicker, inner electron-dense layer, or more likely, that the apochlorotic condition prevents two discs from fusing to produce the thicker inner electron-dense layer which contains the photosynthetic pigments.

Notizen: SYNOPSIS. Cell-free extracts of Tetrahymena contain adenase, guanase, xanthine oxidase, uricase, and adenosine deaminase. The levels of activity of the latter three are of the same order of magnitude as in mammalian tissues. 5′-Adenylic acid deaminase is also present in ciliate extracts. Spectrophotometric assays of this enzyme indicate formation of two intermediates which, although not as yet identified, are not precursors of uric acid, the expected product of deamination of the nucleotide.

Notizen: SYNOPSIS. Trypanosoma conorhini has been isolated from infected Triatoma rubrofasciata in Singapore. Parasites derived from the triatomid gut were inoculated into NNN medium and some cultures maintained at 25° to 27°C while others were kept at 37°. In cultures kept at lower temperatures crithidial forms predominated; however, at 37° blood-stream trypanosome forms developed and survived for 10 days or more.

Notizen: SYNOPSIS. Sporocysts of P. crystalligera readily germinate to permit escape of their sporozoites when placed in an infusion of the contents and the tissue of the midgut of the beetle host, Dermestes vulpinus. To determine the type of digestive enzyme required for germination to take place, sporocysts were exposed in hanging drops to 0.25% (w/v) concentrations of commercial preparations of trypsin and lipase in a saline solution. Sodium taurocholate was used in combination with certain of the enzyme preparations.Up to 99% of the sporocysts exposed to trypsin 1:300 and to a relatively crude preparation of lipase (containing some trypsin) germinated within three hours. A refined preparation of trypsin (2 × crystallized, salt-free) induced up to 65% of the sporocysts to germinate within three hours. Refined lipase (50μl CO2/mg/30 min.) had no germinating effect upon sporocysts, either by itself or in combination with sodium taurocholate. In mixtures, crystallized trypsin seemed definitely to be inhibited by sodium taurocholate, and perhaps was inhibited also by refined lipase.The fact that trypsin is effective in causing germination to take place suggests that the germination of sporocysts in the digestive tract of D. vulpinus depends upon a proteolytic enzyme. Unlike trypsin, which was more active in solutions adjusted to an initial pH of 7.0 and 8.0 (especially the latter, in the case of crystallized trypsin) than in those of pH 6.0, this enzyme was more effective in inducing germination at pH values of 6.0 and 7.0.

Notizen: SYNOPSIS. Two blood trypanosome antigens (PR and AG) have been isolated from the serum of infected rats. These antigens are specific for each strain of trypanosome. The AG antigens, detected by agar diffusion techniques, have been extensively purified and are prctein in nature. Those isolated from two different strains differ in their heat sensitivity and in their elution patterns from calcium phosphate gel. The AG antigens are apparently not involved in the protection of mice after immunization with infected rat serum. The PR antigens, not yet detected by agar diffusion techniques, protect mice after immunization. These antigens also appear to be proteins.At least two antigens in the soluble portion of blood trypanosome homogenates are common to the “brucei” group of trypanosomes. These antigens are not involved in determining the serotype of different strains of trypanosomes. Furthermore, there are no biological properties by which the common antigen can at present be characterized.The enzyme hexokinase has also been found to be antigenically similar in both blood and culture trypanosomes. This enzyme, however, has not been detected by agar diffusion techniques. This, therefore, suggested that there are probably numerous antigens common to different strains of T. rhodesiense which have not been detected by this technique.

Notizen: SYNOPSIS. In continued observations on the in vitro growth and multiplication of the bloodstream trypanosome stage of Trypanosoma conorhini, a better medium was found for cultivating these forms at 37°C, but no subcultures could be obtained. The infectivity for mice of the blood type trypanosomes grown in vitro was comparable to that of the metacyclic trypanosomes. The only reproducing forms of T. conorhini found in the vertebrate were in the trypanosome stage.It was also found that the in vitro reversion of the bloodstream trypanosome into crithidia, such as occurs in the invertebrate host and in the usual diphasic culture medium, is dependent on at least two factors: if incubated at 25–28° reversion did not occur in any of the liquid media tried (all containing blood serum and hematin or hemoglobin), unless total blood was part of the inoculum or washed red blood cells were added to the media; on the other hand, no reversion was seen, even in the presence of red blood cells if the cultures were incubated at 37°.

Notizen: SYNOPSIS. Alkaline (pH 8.4) and acid (pH 5.4) phospha-tases were demonstrated in the cytoplasm of culture forms of Trypanosoma ranarum by the naphthol-AS methods. The enzymes were in both slender and pear-shaped flagellates, and variaticn of incubation temperature (10°, 31° and room temperature) did not adversely influence the appearance of the chromogenic granules. Enzyme determinations by sulfide methods indicated that alkaline phosphatase was concentrated in the nuclear area. Acid phosphatase could not be found by this method.

Notizen: SYNOPSIS. A polymorphic allogromiid (our strain NF) was isolated in monoxenic culture but attempts at its axenic culture failed. Growth of monoxenic cultures was stimulated by various metals and vitamins. The morphology and life cycle of this allogromiid with a prominent collar have been studied in detail. It varied in form from ovoid to elongate bioral “Shepheardella-like” forms and to irregular polyoral organisms. The organisms ranged in length from 56–385 μ (118 μ± 50.54) and in width from 35–385 μ (99 μ± 39.34). The number of nuclei per organism averaged 8.9 ± 6.3 (range 1–40). Reproduction of “Shepheardella-like” forms was by binary fission. Three types of budding have been observed and, rarely, schizogony. No evidence for sexual reproduction has thus far been seen.

Notizen: SYNOPSIS. A nonpathogenic histomonad, morphologically identical to that found in pheasants by Wenrich in 1943, is described as Histomonas wenrichi n. sp. Its dimensions are about 1.5 × those of H. meleagridis. It has 4 flagella instead of the 1 or 2 that characterize the latter species. It does not multiply in the host tissues nor produce visible responses to its presence there, and it does not exist as the clear “tissue form” that is common in active H. meleagridis infections. Histomonas wenrichi n. sp. can be transmitted to turkeys, chickens, and pheasants by either rectal inoculation or by feeding embryonated eggs of Heterakis gallinarum grown in birds harboring the nonpathogenic histomonad in the ceca. Usually fewer than half the female heterakids so grown produce eggs capable of transmitting this histomonad, and a total of 200 to several thousand eggs from worms recovered from Histomonas-infected birds may be required to produce one Histomonas infection. Histomonas wenrichi n. sp. has been propagated in more than 2000 chickens and turkeys over an 8-year period, during which time it has been transmitted by 18 generations of Heterakis. It has frequently been grown in birds in which H. meleagridis was also present, and upon reisolation it maintained all of its original characteristics. It has not yet been cultivated in vitro.

Notizen: SYNOPSIS. Of 6 representative antibiotics only tetracycline inhibits this phytoflagellate. Whereas penicillin, neomycin, erythromycin and streptomycin exert no real influence on the organism, addition of chloramphenicol to the growth medium results in a marked increase in cell yields.

Notizen: SYNOPSIS. The occurrence of monstrous individuals of Dileptus is reported. These monsters appeared in cultures which had been fed planarians for over 72 hr. The first abnormal forms to appear were giants, 700–1200 μ long, which were common in the cultures after 72 hr. Giants were occasionally observed to develop a large, non-contractile vacuole in the central region of the body after a week of feeding on planarians. A sequence of events is described in which this vacuole enlarged until the animal appeared to be a water-filled sphere which then collapsed into an amorphous blob. This blob then divided unevenly to produce as many as seven small Dileptus. The described morphological changes are presumed to be a result of Dileptus' feeding on planarians. The similarities between abnormal Dileptus and monstrous individuals of other species are discussed.

Notizen: SYNOPSIS. Genomic exclusion is an aberration that occurs during conjugation in variety 1 of Tetrahymena pyriformis. Instead of containing markers from both parents, the out cross pairs are either homozygous for all the genes of one parent (unilateral genomic exclusion); or, some of the pairs are homozygous for the genes of one parent and other pairs are homozygous for the genes of the other parent (bilateral genomic exclusion). This phenomenon was first demonstrated in the C strain: some stocks evoke unilateral genomic exclusion; others, bilateral genomic exclusion. C*, inbred for 5 generations, was used to explore this phenomenon in some detail since unilateral genomic exclusion of C genes occurs in almost all pairs in outcrosses of C*. In a mating of C*, both exconjugants are recovered, both are dipioid and similar in phenotype. Using morphological markers, C* can be shown to participate in the mating; therefore, C* does not induce illegitimate matings of the normal mate. When the normal mate is heterozygous for alleles (HA/HD) not present in C*, 3 classes of offspring (HA/HA, HA/HD and HD/HD) are produced in a 1:2:1 ratio. These observations indicate that 2 meiotic products of the normal mate unite to form the syn carya. The genetic ratios obtained in 1 and 2 factor crosses limit the possible cytogenetic bases for genomic exclusion. They suggest that 1 of the 4 haploid nuclei replicates and the replica fuses randomly with any 1 of the 4 nuclei. The 2 schemes of nuclear behavior (single fertilization, double fertilization) that would satisfy these requirements have not yet been resolved.

Notizen: SYNOPSIS. In defined media growth inhibition of the flagellates Ochromonas danica and Euglena gracilis, the photosyn thetic bacterium Rhodopseudomonas palustris, and Coryne bacterium bovis was overcome for each organism, for concentrations of 4-nitroquinoline N-oxide (4-NQO) to ca. 5 μg/ml, by a combination of L-tryptophan, riboflavin, nicotinic acid, L-tyrosine, and less sharply, thymine and naphtho quinones. Tryptophan used alone was effective only in rather high concentrations—ca. 0.2 mg/ml for 4-NQO 2 μg/ml; it was competitive with 4-NQO through this range. At least for Euglena, gramine and 5-methyl-DL-tryptophan were about as effective. 4-NQO uptake may therefore be via the trypto phan transport system. 4-NQO may be a uniquely stable, accessible counterpart of the more polar, more carcinogenic compounds into which mammals oxidatively convert the azodye carcinogens by N-hydroxylation and the hydrocarbon carcinogens by hydroxylation and ketonization.

Notizen: SYNOPSIS. When the antibiotic L-azaserine was injected intraperitoneally into female Ha/ICR albino mice infected with T. equiperdum, a marked but temporary inhibition of trypanosomal reproduction was observed and survival time of the hosts was more than doubled. The efficacy cf a given dose of azaserine was considerably reduced when its equivalent was divided equally over a 5-day period. Azaserine was much more effective when injected intraperitoneally than when given by gastric intubation, even though measures were taken in the latter circumstance to reduce the rate of degradation of the drug by gastric juice and the liver. Some purine analogs were tested in combination with azaserine for ability to prolong the lives of mice infected with T. equiperdum; 6-mercaptopurine was the only one that significantly enhanced the efficacy of azaserine. Evidence is presented that azaserine inhibits trypanosomal reproduction directly rather than by a host-mediated mechanism.

Notizen: SYNOPSIS. Haemoproteus sp. (probably a subspecies of H., columbae Kruse, 1890) of Columba p. palumbus L. in England produces sporozoites in the salivary glands of Ornithomyia avicularia L. and has been transmitted by the bite of this insect. The parasite has also been isolated from naturallyinfected O. avicularia. Observations on experimentally-infected birds have shown that the macrogametocytes reach their full size in six days, and the microgametocytes in five. The taxonomy of the genus is briefly discussed.

Notizen: SYNOPSIS. Euglena gracilis (strain Z) was grown auto-trophically at different light intensities, saturating or limiting for cell division. Adaptation to culture at each light intensity was gauged from division rate, mass, protein, photosynthetic pigments, nucleic acids, volume, paramylum, lipids, respiration, and photosynthesis. Illumination above 1200 foot-, candles was saturating for all aspects of cell growth; the highest intensity examined (3,000 ft-c) slightly inhibited cell division. Intensities between 400 and 1200 ft-c were saturating for all except photosynthesis and paramylum accumulation. Intensities less than about 200 ft-c became limiting for all fractions except protein, which remained constant over the range 120–3000 ft-c, dropping, however, at 65 ft-c. Concentration of photosynthetic pigments increased as light intensity decreased.Absolute synthetic rates were estimated for the individual Euglena cell for the measured cell constituents. While most followed a predictable pattern, increasing with light intensity to saturating levels, the synthetic rates for the pigments went through maxima at 190 ft-c. Since fixed carbon in limiting light is so apportioned that protein is synthesized to the exclusion of paramylum, one concludes that the energy requirements for cell growth (measured as protein synthesis), and to a lesser extent cell division, have a higher priority than do those activities concerned more directly with maintenance.

Notizen: SYNOPSIS. Nucleocytoplasmic relationships were explored by producing the extreme alterations in proportion of macronucleus to cytoplasm for which the ciliate Stentor coeruleus is uniquely suitable. Cytoplasmic volumes were varied from about 40 to 6000 times the nuclear volume, as compared with a normal range of approximately 126 to 387. 1. Neither gross reduction nor great excess of the nuclear complement stimulate or inhibit cell division; for division never promptly ensued nor were giant cells or dwarf lines produced. Previous studies(5) have shown that lesser variations in nucleocytoplasmic proportions also have none of these consequences. 2. Hypernucleation produces no noticeable accelerating effect on cell re-differentiation (oral regeneration), ciliary activity (swimming and feeding), or growth and multiplication. 3. Overnucleation is adjusted by extensive fusion of macronuclear nodes (reducing nuclear surface area) and by gradual resorption of some of the nucleus. 4. Nucleus maximally reduced to one node in normal and greater amounts of cytoplasm almost always results in delays of 2 to 15 times the usual preparatory period for regeneration as well as diminished feeding and impaired digestion, and acts as a stimulus to reorganization—confirming Schwartz(27). In hyponucleates there is a compensatory increase in nodal number following regeneration, reorganization (or division), but only after oral primordium formation—again confirming Schwartz. At least two such formations (regeneration followed by reorganization or division) are required for recovery of a nuclear complement of normal proportions, and this very probably represents a true increase in macronuclear substance as well as in number of nodes.6. In division the number of macronuclear nodes is approximately doubled, such that each fission product begins with about the same number as the parent cell, but the new nodes are generally smaller. Whether, during interfission, a regular increase in size of nodes and the addition, at most, of 3 new nodes represents a real increase in nuclear substance is questionable in view of the fact that isolated single nodes remain as such for days without increase until oral primordium development. Cytosomal events may be said to give the stimulus to renodulation and possibly also to macronuclear growth as they do for micronuclear growth in mitosis.7. When the nucleus is maximally reduced, the single node may be resorbed and no oral regeneration occurs. Alternatively, the macronuclear bead supports delayed regeneration but fails, temporarily or permanently, to increase itself. Less commonly, neither oral nor nuclear regeneration occurs though the single node persists. All indicate a statistical probability of some injury to a reduced nucleus when in an excess of cytoplasm. 8. Early oral primordia are resorbed in regenerators (and dividers and reorganizers) when the macronucleus is reduced to one node, but the single node which could not support continued regeneration is nevertheless sufficient for subsequent re-regeneration. 9. At most the oral primordium can develop 3 steps further (more often 2, sometimes none) after complete enucleation. Hence there is little storage of nuclear support. Stage-5 anlagen, still without visible trace of mouth-parts, can develop fully, suggesting there is little synthesis of materials in later development but largely morphogenetic movements of invagination and translocation in completion of the feeding organelles.10. Enucleated stentors can feed quite well at first but not at all later. All indications are that they are incapable of digesting food organisms. Mononodal stentors fare somewhat better and recover normal function as they regenerate the nuclear chain. Enucleates die on the average sooner than starved nucleate controls, but there is considerable overlap in survival times.Some inferences from these findings are discussed. In experiments with other concerns, a sufficient amount of macronucleus should be used or retained, else the disproportion becomes a factor in itself.

Notizen: SYNOPSIS. The motility of Tetrahymena pyriformis is inhibited by quaternary ammonium compounds of the type that has neuromuscular blocking activity (such as decamethonium salts). The effect on the cell is reversible by dilution and appears to be non-lethal for prolonged periods. Curare has no effect at concentrations tested. Paramecium caudatum appears to react similarly to T. pyriformis. The results are discussed in view of acetylcholine mediated ciliary beat.

Notizen: SYNOPSIS. A leptomonad zooflagellate infecting the macronucleus of Paramecium trichium is described. The cell body of Leptomonas karyophilus n. sp. is 5μ long and the flagellum is 12μ long. There is a central ovoid nucleus, a bar-shaped kinetoplast and a contractile vacuole. The flagellate undergoes division in the macronucleus, proliferating there until it has killed its host. Mildly infected paramecia are able to divide and if fed regularly can be maintained carrying the parasite. Cross infections with P. caudatum, P. bursaria and P. aurelia were successful to varying degrees.

Notizen: SYNOPSIS. The carbonic anhydrase inhibitor 2-acetylamino-1,3,4-thiadiazole-5-sulfonamide-sodium prevents mineralization in the coccolithophorid Hymenomonas sp. in concentrations which still permit the growth of organisms.

Notizen: SYNOPSIS. A study of regeneration of trichocysts in Paramecium caudatum was made in the electron microscope. Organisms, from which trichocysts were removed en masse with electric current, were allowed opportunity to regenerate their lost organelles before they were prepared for microscopical examination of developing stages.Thin sections of organisms from various regeneration periods demonstrate clearly the endoplasmic origin and development of trichocysts. The first stage seen is a membrane-limited, endoplasmic vesicle enclosing an homogeneous mass, the primordium, within which appears a minute, point condensation of greater electron density. This is subsequently elaborated as a closely packed system of linearly oriented fibrous elements (30–50 Å)—the first definitive sign of the presumptive trichocyst. By progressive utilization of the intra-vesicular primordial matter in association with apparently continuous provision of the building material by extra-vesicular biosynthetic activity, the form and structure of the juvenile trichocysts recognizable as a system of closely packed, multi-layered, fibrous sheets become increasingly evident. The basic structural patterns extend also into the now developing tip. Further growth and differentiation involving the transition of its gross shape from oval to oblong effect a second notable morphological transformation: the formation of a dense U-shaped cortex enclosing a lightly stained center. Full maturation of the trichocyst includes the formation of the cap, disappearance of the limiting membrane, reduction and ultimate loss of the dense cortex with simultaneous assumption of light electron stain homogeneity of the body, and elaboration of the characteristic periodic striation of the tip. These neo-formative events, which also occur—although with reduced frequency—in normal vegetative forms, in conjugating pairs, and in dividing organisms, are concluded prior to the final positioning of the organelle in the bipolar ciliary meridian.The implications of these findings are discussed in light of current hypotheses concerning the role of the nucleus and ciliary basal bodies in the genesis of cortical organelles.

Notizen: SYNOPSIS. Genus Haplosporidium Lühe, 1900 (=Aplosporidium Caullery & Mesnil, 1899) now contains an incoherent group of about 25 species with spores of very diverse morphological types or with spores unknown. Therefore, such limited revision of the genus as present knowledge permits is proposed. H. scolopli (C. & M., 1899) Lühe, 1900, is selected from the two genosyntypes as type species. An essential generic character is that the anterior end of the spore opens like a lid to provide an orifice for emergence of the sporoplasm. The following nine species are rejected because their spores seem to lack the lid (operculum, clapet): H. mytilovum Field, 1924; H. gammari Van Ryckeghem, 1930; H. aulodrili Jírovec, 1940; H. ecdyonuris Weiser, 1947; H. bayeri Weiser, 1947; H. aselli Pflugfelder, 1948, H. tapetis Vilela, 1950; H. periplanetae Georgevitch, 1953; H. typographi Weiser, 1954. H. chitonis (Lankester, 1885) Debaisieux, 1919, must, in accordance with the law of priority, be put back into genus Minchinia which was created for it by Labbé in 1896 and erroneously suppressed by Debaisieux in 1919. Therefore, its correct name is M. chitonis (Lankester, 1885) Labbé, 1896, and genus Minchinia is restored. The type species of Haplosporidium and Minchinia, H. scolopli and M. chitonis, are deemed to have distinctive characters of generic rank which justify conserving both genera. Species with the lid lying over the orifice, rather than in it, and extending beyond the perimeter of the orifice are transferred from Haplosporidium to Minchinia. The latter then contains eight species: M. chitonis (Lankester, 1885) Labbé, 1896; M. limnodrili (Granata, 1913); M. nemertis (Debaisieux, 1919); M. cernosvitovi (Jírovec, 1936); M. dentali (Arvy, 1949); M. sp. (Sprague, 1954); M. pickfordae (Barrow, 1961); M. costalis (Wood and Andrews, 1962). Left in Haplosporidium, with reservation in the last two cases, are eight species: H. scolopli (C. & M., 1899) Lühe, 1900; H. heterocirri (C. & M., 1899) Lühe, 1900; H. vejdovskyi C. & M., 1905; H. marchouxi C. & M., 1905; H. potamillae C. & M., 1905; H. caulleryi Mercier & Poisson, 1922; H. ascidiarum Duboscq & Harrant, 1923; H. sp. Dehorne, 1935.

Notizen: SYNOPSIS. Free amino acids in extracts of a number of tetrahymenid genera, species and strains of Tetrahymena pyriformis were separated by a combination of paper electrophoresis at pH 1.9 and descending paper chromatography with lutidine as solvent. Ethanol extracts of ciliates cultured at temperatures of either 15°, 25° or 35°C were used. Relative evaluation of ninhydrin spot intensity was made for T. pyriformis strains WH52, UM226, hybrids No. 25, No. 76, PR, HS and N. Extracts from 15° and 25°C cultures of T. limacis, T. setifera HZ1, T. vorax V2, Glaucoma chattoni A and Colpidium campylum C were analyzed in the same way.Seventeen spots were usually found on all chromatograms indicating the presence of the substances alanine, arginine, aspartic acid/asparagine, cysteine/cystine, glutamic acid/glutamine, glycine, histidine, leucine, lysine, methionine, phenylalanine, proline, serine, taurine, threonine, tyrosine and valine. No cysteic acid was demonstrable. Cysteine/cystine, histidine, phenylalanine and taurine generally occur in relatively low concentrations or appear to be absent. Those ranked as generally abundant include aspartic acid/asparagine, arginine, serine and threonine. Spot intensities for the remainder of those listed above indicate they were very abundant in most samples.FAA analyses have now been made by us, including those in a previous report, on tetrahymenid ciliates belonging to 3 genera (Colpidium, Glaucoma and Tetrahymena), on 4 species of Tetrahymena (limacis, setifera, vorax and pyriformis) and on 11 strains of T. pyriformis. Although extracts have been compared from ciliates grown at temperatures of 10°, 15°, 25° and 35°C, no striking differences in the qualitative or quantitative composition of the known amino acids in these patterns were observed. It was not possible to establish correlations with serotypes, and no features that might serve as useful taxonomic criteria were observed.

Notizen: SYNOPSIS. In axenic culture, the polymorphic ciliate, Tetrahymena patula, consists of two cell types, a small mouthed form (microstome) and a larger carnivorous macrostome both of which possess the tetrahymenal-type buccal apparatus. With the exception of over-all size, only minor differences were found in the structure of the oral area of the two cell types.Each of the membranelles, which lie on the left wall of the buccal cavity, consists of three long rows of kinetosomes with attached cilia. A series of parallel fibers originating at the base of the inner row of kinetosomes in each membranelle runs toward the adjacent, lower membranelle or in the case of the third membranelle toward the junction of the left and right walls of the buccal cavity. After a short distance, a portion of each fiber rises and subdivides to form a periodic array of fine fibrils which lie immediately under the pellicle and run parallel with the long axes of the membranelles. The remaining portion of these kinetosomal fibers continues through the cytoplasm to connect with the kinetosomes of the next membranelle.The undulating membrane, which borders the right wall of the buccal overture, consists of a single row of cilia. Examinations of thin sections show, however, that there are actually two rows of kinetosomes in the membrane base. The outer row is ciliated while the inner row of kinetosomes, which are alternately spaced relative to those in the outer row, lies deeper in the cytoplasm and has no cilia. Fibers project straight down from the base of kinetosomes in both rows and join to form a tangled network which underlies the entire length of the membrane.The oral ribs begin near the base of the undulating membrane and descend in decreasing number to the cytopharynx. There is a connection between the fiber system of the undulating membrane and the tips of the oral ribs. The ribs appear in cross section as raised, thickened ridges of the inner pellicular layer with the outer layer adhering only at the top of the ridges. Immediately underlying the oral rib area is a relatively thick differentiated layer composed of fine fibers within a ground substance.

Notizen: SYNOPSIS. Cell volume and nuclear volume measurements were made on Tetrahymena pyriformis strain E cells that had been either (a) suspended in a medium deficient in some nutrient or (b) suspended in a medium containing a metabolic inhibitor. Media deficient in a nucleotide or containing nucleotide analogs did not significantly inhibit growth. However, cell volume changes were observed for cells grown on nucleotidedeficient medium. Amino acid deficient medium inhibited growth completely and both cell and nuclear volume decreased significantly. The minimal volumes attained were 2/3 of the control volume. Media containing amino acid analogs did not completely inhibit growth nor did appreciable volume changes occur. Both cell and nuclear volumes were closely intercorrelated throughout the results.

Notizen: SYNOPSIS. Cell volume and nuclear volume of Tetrahymena pyriformis strains HS and E, grown on a defined medium, were measured as a function of age of culture, age of cell and generation time. The volume of an “average” single cell between divisions was calculated for logarithmic phase cultures by using volume distributions and difference equations. Cell volume measurements were made by compressing the cells to known thickness and measuring the area from photomicrographs. The nuclear volume was determined from diameter measurements of the nucleus by assuming the shape of a sphere.The cell volume decreased from the lag phase to the logarithmic phase and reached a minimum at the end of the logarithmic phase. It increased again during the stationary phase. The nuclear volume also decreased from the lag to logarithmic phase, but continued to decrease in the stationary phase until it reached the nuclear volume of the daughter cell. The average single cell volume increased at a constant rate for 85% of the generation time, at which point the rate diminished to zero. The nuclear volume showed no increase until 35% of the generation time had passed. It then increased at an accelerated rate which diminished just before division. Both the average cell and nuclear volumes decreased with increase in temperature until the optimum temperature was reached, at which point they increased again. There were no appreciable differences in volume changes for cells grown on different media.

Notizen: SYNOPSIS. Axenic and monobacterial cultures were utilized to study the ultrastructure of the amoeboid and flagellate stages in the life-cycle of Naegleria gruberi. The cytoplasm of the amoeboid stage is poor in electron-dense components; a loosely organized endoplasmic reticulum is present. The absence of cytoplasmic inclusions in the ectoplasm is the only detectable difference between it and the endoplasm. The nucleus of Naegleria is typically vesicular. The mitochondria are of the type commonly found in protozoa. Food and contractile vacuoles are described. No Golgi apparatus has been found.The general ultrastructure of the flagellate resembles that of the amoeba. The kinetic apparatus consists of flagella and their associated kinetosomes, a “spur” made up of isodiametric fibrils (14 mμ in diameter) attaching to the base of the kinetosome, a cross-striated rhizoplast, and thin-walled fibrils (22 mμ in diameter) with a center of attachment in the kinetosomal complex.Neither centrioles nor kinetosomes have been found in the amoeba. Complex arrangements of endoplasmic reticulum have been seen in the cytoplasm of transforming individuals which may be points of origin of the kinetosomes and/or flagella. The nuclei in metamorphosing individuals frequently show unusual plasticity.Some speculations on possible orgins and affinities of Naegleria are included.

Notizen: SYNOPSIS. The subcortical network identified as a leucoplast in Polytoma by some light microscopists actually consists of a system of branching mitochondria. A starch-bearing plastid which may also contain stigma granules occurs beneath the mitochondrial layer. Tubular profiles in the plastid similar to those seen in a Chlamydomonas mutant may be significant to the hypothesis of the origin of Polytoma from a Chlamydomonas-like organism by step-wise loss of chlorophyll-synthesizing ability. The basal bodies of the two typical flagella are connected by an additional broad fibril which arches across the anterior papilla.

Notizen: SYNOPSIS. The environmental factors causing encystation in Hartmannella rhysodes, a small soil amoeba, appear to be an elevated osmotic pressure, Ca2+ and Mg2+, aeration and a decrease in carbon sources. After 36 hr under these conditions, amoebae harvested during active growth encyst. Nutrients essential for growth, other than carbon sources, have no effect on encystation. The factors which bring about encystation are components of the defined medium, in which the minimum essential organic requirements for growth are known.

Notizen: SYNOPSIS. Methods have been developed for the isolation of deoxyribonucleic acids (DNA) from Tetrahymena pyriformis, Polytomella papillata, and Aspergillus tamarii. The DNA from these organisms contained adenine (A), thymine (T), guanine (G) and cytosine (C), and the usual base-pairing relationship, i.e., A = T; G = C was found. The ratio A + T/ G + C was 2.42, 1.42, and 1.08 for the DNA of the three organisms respectively. 5-Methylcytosine was absent in all cases.

Notizen: SYNOPSIS. Seven monoxenous Trypanosomatidae, Crithidia fasciculata (Anopheles strain), C. fasciculata (Culex pipiens, Wallace), C. fasciculata (Culex pipiens, Nöller), C. luciliae, C. sp. from Euryophthalmus, “Strigomonas” oncopelti and Blastocrithidia culicis all are catalase-positive. S. oncopelti is only catalase-positive when grown in hemin-media. When grown at elevated temperature, C. fasciculata (Anopheles), C. luciliae and S. oncopelti have greater and C. fasciculata (Culex pipiens, Wallace) reduced catalase activity. C. fasciculata (Culex pipiens, Nöller) and C. sp. from Euryophthalmus show reduced catalase activity at elevated temperature that is of borderline significance.Catalase as a phylogenetic marker is discussed.

Notizen: SYNOPSIS. An electron microscope study has been made of the spores of a microsporidian, Thelohania californica, parasitic in Culex tarsalis. Fresh spores measure 7–9 × 5–6 μ and contain a polar filament which when extruded may reach a length of 150 μ or more. Thus, this is a typical microsporidian spore. The spore is enveloped in a resistant outer membrane. The polar filament is attached to this membrane at the narrow anterior end, runs inward for a distance and is coiled spirally close to the inner surface of the outer membrane. There are 12–14 spiral turns in the majority of the spores. In the anterior five turns the filament is distinctly larger in diameter than in the seven or more posterior coils. The polar filament appears to be tubular, but the lumen is filled partially or completely with material of high electron density. A laminated polaroplast surrounds the basal portion of the filament and extends into the middle and posterior regions of the intrasporal cavity. The sporoplasm is uninucleate and lies in close contact with the polar filament and the polaroplast. There is no polar capsule.

Notizen: SYNOPSIS. The effect of H. gallinacea infection on the phagocytic activity of the reticulo-endothelial system in chicks has been investigated. Changes occurring in the pattern of R.E. activity show that there is initial stimulation of phagocytosis within 24 hr and that this increases up to the 4th and 5th days after which time parasites appear in the blood. Thereafter there is a rapid drop in R.E. activity with a proportional increase in parasitaemia following which death ensues. The importance of the protective value of the reticulo-endothelial system is indicated and it is suggested that a toxin produced by the parasites or by their break-down products is the likely cause of phagocytic depression.

Notizen: SYNOPSIS. The inhibitory principle in whole blood for strains of Euglena gracilis has been characterized and identified as hemoglobin. Hemoglobins from different sources were tested for their inhibitory activity and gave similar results. The inhibition was reversed by raising the concentration of certain divalent metal ions, calcium in particular in the basal growth medium. The nature of the inhibition was studied. Heme and other porphyrins related to hemoglobin stimulated the growth of Euglena gracilis in light. Implications of these findings are discussed.

Notizen: SYNOPSIS. Four strains of ciliates regarded as strains of Tetrahymena vorax were studied nutritionally and serologically. All grew on a chemically defined medium and phospholipid was generally stimulatory. It is concluded from the results of the present study, together with information available in the literature, that two of the strains (V1 and PP) are actually strains of T. pyriformis. This leaves T. vorax represented by two extant strains, V2 and Tur, both of which are polymorphic.Evidence is presented for “stable transformations” in two of the strains included in the study, i.e., stocks have spontaneously developed phenotypic differences which are uniparentally inherited. The potential importance of studies of uniparental inheritance for physiological and developmental genetics is discussed.

Notizen: SYNOPSIS. Three morphologically indistinguishable species, Entamoeba histolytica, E. invadens and E. moshkovskii, were compared with regard to the effect of temperature. Temperature tolerance studies showed that the thermal endpoints (100% death) of DKB and the Laredo strains of E. histolytica, DSR strain of E. moshkovskii and IP strain of E. invadens were in the descending orders of 43°, 41°, 41° and 39°C respectively. DKB strain seemed to be very sensitive to temperatures below 30°C. The Laredo strain of E. histolytica and DSR strain of E. moshkovskii were similar in their range of temperature tolerance.The DKB strain of E. histolytica has been adapted to grow at 30°C and IP strain of E. invadens at 35°C, with Clostridium perfringens as the associate in both cases. Comparison of normal and temperature-adapted strains of the three species of Entamoeba with respect to population cycle showed that at higher temperatures the multiplication rate is higher and the population reaches its peak in 2 to 3 days, whereas at the lower temperature the multiplication rate tends to decrease and the maximum population is reached by the 4th day. Individual trophozoites from the 30°C-adapted strain of E. histolytica were larger than those of the parent strain grown at 37°. Amoebae of the IP strain of E. invadens adapted to 35° were smaller than those of the original strain grown at 30°.The observations indicate that the Laredo strain of E. histolytica, isolated from a patient with amoebic dysentery, is an unusual mutant of a typical strain of E. histolytica, which on one hand shows affinity with typical E. histolytica and on the other hand with E. moshkovskii and E. invadens.

Notizen: SYNOPSIS. It is known that hydras infected with H. hydroxena commonly disintegrate and release scores of amoebae. Spherical resting bodies found among the free amoebae have been described as cysts and it has been suggested that they give rise to amoebulae. Using Hydra pseudoligactis as the host, a study was made of the history of the free amoebae and of the structure, nature, and fate of the so-called cysts. All such amoebae transformed into spherical bodies that resembled cysts, even to the presence of an external membrane. These bodies invariably disintegrated after 2–3 days and they never produced amoebulae. They were called pseudocysts. The external membrane proved to be a layer of gelated cytoplasm. Unlike a true cyst membrane, it dissolved in KOH and it underwent solation when the pseudocyst disintegrated. It is concluded that the pseudocysts are actually weakened, starved, moribund amoebae. At present there is no evidence that H. hydroxena is capable of producing true cysts; its transmission from host to host appears to be solely by means of the amoeboid trophozoite.

Notizen: SYNOPSIS. Normal Euglena gracilis, strain z, growing in the light in defined medium (initial nitrogen concentration 140 μ/ml) depletes the medium of all ninhydrin-positive N by the time a cell density of 2 million per ml is reached. A further 2- to 3-fold increase in the cell number takes place in the absence of exogenous N. The N content of an early log phase cell is about 100 picograms but decreases very rapidly as the culture continues to grow, reaching 22 picograms in the stationary phase. When grown in the dark, normal cells take up N somewhat more slowly but the supernatant fluid from saturation cultures is again devoid of N.At modest cell densities, the permanently bleached strains examined contain less N per cell than do normal strains. The cultures of the bleached strains achieve a maximum density of about 1 to 2 million per ml rather than the 4 to 5 million reached by the normal strain. As a result, supernates from stationary phase cultures of bleached cells still contain a large proportion of the total N supplied.Paper chromatographic analysis of these supernates reveals several ninhydrin-positive compounds. Most of these have been identified as common amino acids. Some of the properties of two unidentified, ninhydrin-positive compounds are described.

Notizen: SYNOPSIS. Haplosporidium sp. Sprague, 1954, originally reported without description and now considered to belong to genus Minchinia, is described. Vegetative forms with two to many nuclei are common but the mode of vegetative multiplication is obscure. Mitotic division, as in related species, occurs without breakdown of the nuclear membrane and shows a conspicuous intradesmose. A complex endosome resembling an amphinucleolus gives rise during prophase to chromosomes, nucleolus and (probably) centrioles. The minute chromosomes are not easily resolved or distinguished from other nuclear elements but their number is of the order of 3 to 6. Mature spores are ovoid and average about 12.1 μ by 8.4 μ when fixed and stained. The spore wall, about 1 μ thick, contains a circular orifice 2 μ in diameter. An operculum arising from the outer gelatinous coat covers the orifice. The single uninucleate sporoplasm is attached anteriorly to the perimeter of the orifice. Cysts are spherical and with variable number of spores, usually too many spores to count but rarely as few as 8 or 16.

Notizen: SYNOPSIS. Eimeria acervulina infections were studied by counting oocysts collected from individual chickens before they passed into droppings. More oocysts of E. acervulina were produced on day 4 post-infection than at any other time. The reproductive potential per oocyst decreased as the infecting dose increased. The mean numbers of oocysts present in the intestine after 4 days were 6,590 per oocyst fed when the infecting dose was 10,000 oocyts; 6,180 when it was 50,000 oocysts; 4,150 when it was 100,000 oocysts; 444 when it was 1 million oocysts; and 71 when it was 10 million oocysts. Oocysts become infective within 13 hours sporulation at 30°C, reach a peak of infectivity before 27 hours and start to decline after 60 hours. Oocyst yield increased linearly with age, from a mean yield of 80.1 × 106 oocysts in the intestine of 13-day-old birds to a mean yield of 1223 × 106 oocysts in the intestine of 107-day-old birds. There was a seasonal effect upon oocyst yields, with higher yields in the winter during the year in which observations were made.

Notizen: SYNOPSIS. Axenic and monobacterial cultures of Naegleria gruberi were utilized to study the ultrastructure of encysting amoebae, mature cysts, and excystation stages. Encystation is characterized by an increase in cytoplasmic density due to dehydration. The mitochondria appear to be undergong division and are found closely associated with elements of the endoplasmic reticulum. Numerous vacuoles (or droplets) of low electron density occur in proximity to the nucleus and scattered throughout the cytoplasm. These are thought to contain the material which gives rise to the cyst wall. Other types of vacuoles are described. The mature cyst wall is double, consisting of an inner thick component (200–450 mμ) and an outer thin component (25 mμ). Both elements of the cyst wall show an affinity for osmium. The two layers are separated by a space filled with a spongy network but join at the region of the cyst pore. The pores (about 600 mμ at maximum diameter) are closed by a plug of electron-transparent material. At excystation, the amoeba cytoplasm becomes highly alveolar. The plug sealing the pore in the wall dissolves and the amoeba leaves the cyst.

Notizen: SYNOPSIS. Carpilodes rugatus from Coconut Island, off the windward side of Oahu, was infected to the extent of 65% with intestinal gregarines. Infection was frequently heavy, especially with the intracellular stages. Two new species of Cephaloidophora are described. C. carpilodei n. sp. showed multiple infections in single host cells; as many as three fully developed trophozoites were found in one intestinal epithelial cell of the mid-gut. C. pinguis n. sp. was markedly different morphologically from C. carpilodei. In both species, intracellular development was prolonged with eventual production of septate trophozoites larger than the host cell. The gregariousness of the hosts was believed to facilitate intraspecific infection.Although other species of Xanthid crabs from the immediate vicinity were examined for gregarines, the other host species either were not parasitized or they contained gregarines belonging to species different from those found in C. rugatus. This was true even of host species placed in the same genus. Failure of these parasites of C. rugatus to become established in other species of Xanthids living in such close proximity is evidently due to biochemical or physiological barriers in the latter forms.

Notizen: SYNOPSIS. Under “resting” conditions, synthesis of chlorophyll and alkaline fructose-1,6-diphosphatase in etiolated Euglena gracilis placed in light was repressed by metabolizable carbon sources. The degree of repression by any carbon source apparently depends on its rate of utilization by Euglena. Thus, pre-adaptation of Euglena to a specific carbon source, e.g., glucose or ethanol, increased the repression of chloroplast synthesis in the light by that carbon source. Acetate and malate were not as repressive as ethanol. The similarity of this repression to the “glucose effect” is discussed.

Notizen: SYNOPSIS. Current theories for explaining movement in Amoeba are the contraction-hydraulic and the fountainstreaming theories. The first assumes that plasmasol is pushed by hydraulic pressure developed by contraction of posterior gel. The second assumes that plasmasol is pulled by a condensation process at the anterior end of the gel tube. By means of time exposures (5–10 seconds) under dark-field illumination it has been possible to obtain direct photographic traces of the movement of particles of the sol and of the gel. These demonstrate that: 1) Some advancing pseudopods display no background movement of particles at the tip. 2) Some granules move straight to the very tip in the central portion of an advancing pseudopod, and do not curve to either side until later. 3) In one withdrawing pseudopod, all of the granules of the gel moved simultaneously inward and perpendicularly to the flowing plasmasol along the entire length of the pseudopod. 4) In the anterior portion of the pseudopod the large granules of the gel may move forward. Furthermore, 5) There is a general anteriorly directed fluid flow detectable by observation of very fine granules through the interstices of the gel tube and also through the hyaline ectoplasm. 6) There is a forward flow throughout the entire cross section of the anterior portion of an advancing pseudopod, namely gel, interstices of the gel, sol, ectoplasm, and plasmalemma. It is concluded that the fountain-streaming theory is incompatible with the above facts, and that these can be explained by the contraction-hydraulic theory.

Notizen: SYNOPSIS. Three new varieties of Ch. mundana Gerloff, clearly different from the type are described. In two of these, var. simulans and var. globulosa, the eyespot is reduced to a variable extent and absent from most individuals. The third, var. astigmata, completely lacks an eyespot. Presence or absence of the eyespot can serve to differentiate subspecific taxa but not species of Ch. mundana. The nomenclature and systematics of the 5 known varieties of this species are discussed.

Notizen: SYNOPSIS. The common lemurs Galago demidovi thomasi and Perodicticus potto ibeanus of the African rain forest in Kivu province, (Congo), all showed trypanosomes in the circulating blood. On examining a number of the animals for long periods of time, the trypanosomes proved to belong to two different species, T. perodictici Reichenow (1917) and T. irangiense, van den Berghe, Chardome and Peel, 1956. These two species correspond with the two types previously seen by Hoare, (1932) in P. potto.

Notizen: SYNOPSIS. A study of the ‘longitudinal fibrillar bundle’ (LFB) and the ‘contractile fibrillar system’ (CFS) of a large protozoan ciliate, Spirostomum ambiguum, has been performed by means of an electron microscope. A system of sub-pellicular fibrils has been newly found and its function is discussed. Each LFB runs parallel with a longitudinal row of ciliary bases. It seems to be identical with the so-called kinetodesma. It is composed of tubular fibrils arranged in layered sheets, each of which contains 13 to 35 fibrils with the same diameter as the intra-ciliary fibrils and has a close connection to each of the ciliary bases. The CFS lies on a transitional plane between ectoplasm and endoplasm of the organism and forms a cobweb-like system of myofibrils as a whole. It stands in an intimate relationship with a characteristic vacuolar system. In a peristomial field, the fibrous structures are interrupted and somewhat thickened. A sub-pellicular system is composed of minute fibrils 20 to 26 mμ in diameter. The fibrils run parallel with each other in an antero-posterior direction, immediately beneath the inner pellicular membrane.

Notizen: SYNOPSIS. Anuran bile pigments when concentrated in the large intestine at elevated pH levels, may diffuse into the cytoplasm of opalinids, there be reduced to stercobilin and crystallized. Stercobilin crystals persisted unchanged in Zelleriella cultured in vitro for 14 days. No apparent interference with the normal activities of the protozoa was observed.

Notizen: SYNOPSIS. A trypanosome of the broad type belonging to the T. megadermae group has been discovered in the insectivorous bat, Hipposideros caffer Sundevall. No new specific name is proposed for the trypanosome. Bugs, Stricticimex brevispinosus Usinger 1959, were found infected with the bat blood forms in the stomach. Development was most active in the hindgut, the metacyclic trypanosomes being found in the rectal ampulla.Transmission must occur by contamination as is the case for T. lewisi (fleas), T. cruzi (bugs), and T. grayi (Glossina palpalis flies). With this contaminative type of infection now sufficiently established, it is highly probable that all trypanosomes known from Cheiroptera are transmitted in the same way which is classical for the trypanosomes belonging to the T. lewisi group defined by Hoare.

Notizen: SYNOPSIS. A method is given for the isolation and purification of relatively intact Pandorina morum flagella. Rabbit antisera to flagella of three different strains of the alga, representing each of the two mating types in one syngen and one of the two mating types in a second syngen, were tested. Microscopic examination revealed that antisera caused shedding of flagella and appeared to inhibit their regeneration. Homologous antiserum was capable of immobilizing colonies, agglutinating flagella, and forming multiple precipitin bands in agar when tested against flagella. The effects of an antiserum on the immunizing strain of alga and on its complementary mating type were indistinguishable by the three immunological reactions. Where additional strains of a syngen could be tested, they were also found to react with the antiserum, though the strains were originally collected on different continents. Observable effects of antisera were generally restricted to strains within the same syngen as the immunizing strain. In one exceptional case, however, strains sexually incompatible with the immunizing strain, but originally collected from the same pond, reacted with the antiserum in all three types of serum tests.

Notizen: SYNOPSIS. It is concluded that the trypanosomatid flagellate, Crithidia (Strigomonas, Herpetomonas, Lepiomonas) oncopelti, contains a bacterial endosymbiote, which provides the protozoon with biosynthetic capabilities and, hence, with a measure of nutritional independence; the protozoon in turn gives the endosymbiote the protection of an intracellular environment. Tracer experiments show that C. oncopelti has the “bacterial” kind of lysine pathway (via α,ε-diaminopimelic acid). Diaminopimelic decarboxylase, the last enzyme in this pathway, is associated with the endosymbiote. Electron micrographs of the endosymbiote reveal structures consistent with a cytoplasmic membrane and a cell wall. Endosymbiotes that are dividing, as judged by the presence of a constriction, exhibit membrane septa. Additionally, there are zones that are interpreted as representing nuclear material. The protozoon is “cured” of the endosymbiote by treatment with penicillin in a complex medium. The absence of the endosymbiote from “cured” protozoa can be checked with a staining method that permits the reliable detection of the endosymbiote in untreated protozoa.

Notizen: SYNOPSIS. Cells of variety 1, Tetrahymena pyriformis, manifest different immobilization antigens when grown at 15d̀ and 25d̀C. These differences are partially maintained for a period of growth at an intermediate temperature. Crosses were performed at intermediate temperatures between parental cultures conditioned to high and low temperatures and the antigenic characteristics of their progeny were determined. When conjugation is abortive and paired cells do not complete conjugation, the cells separate and produce clones with distinctive serotypes. When conjugation is completed, however, no systematic differences between exconjugants can be demonstrated. These results differ from those obtained under comparable circumstances in Paramecium aurelia, and fail to support the idea that the cytoplasm plays a significant role in the maintenance of serotypes in Tetrahymena.

Notizen: SYNOPSIS. Highly purified α and β toxins of staphylococci, reported by others to be lethal for paramecia and entamoebae, proved harmless to Paramecium caudatum and Tetrahymena pyriformis.

Notizen: SYNOPSIS. In excystment the primordium of adoral membranelles (AZM) arises as one granular row stretching meridionally toward the cortical axial poles, growing to several rows. Then the AZM's primordial granules become compactly aggregated with a leaf-like form. A separate primordium for the undulating membrane also appears as well as cirral primordia, all in arrangement similar to that in dividers and regenerators of the present species. Though it is difficult clearly to decide from where all these primordia are derived, their formation seems to have a morphogenetic relation to the thickening of certain fibrillar structures appearing only in resting cystic stages.Re-encystment is induced when the excysting cysts after the appearance of a contractile vacuole are transferred to Osterhout's solution from hay infusion employed for excystment induction. Re-encystment follows after the final step of excystment differentiation is accomplished but with aborted rupture of cyst walls. In the resulting re-encysted cyst, the secondary cyst walls are enclosed within the original ones. Repeated treatment can produce cysts with further supernumerary cyst walls by additional formation of third walls.Protoplasts in re-encystment show characteristics similar to animals prior to and after precystic stages. When their original cyst walls are removed, the naked protoplasts obtained take any one of the following courses: 1. recovery of normal form; 2. physiological regeneration; 3. irreversible encystment. Case (1) occurs in naked protoplasts from early stages of re-encystment; case (2), in those prior to the extrusion of excretory granules seen in the course of re-encystment; and the case (3), in those after their extrusion. From these results, presumably the removal of an incipient state of physiological regeneration in the course of re-encystment may be essential for dedifferentiation of the ciliature that redifferentiated fully in the preceding excystment without escapement.

Notizen: SYNOPSIS. Cells of Astasia longa (Jahn) were grown on a simple defined medium, fixed in the stationary phase of growth with OsO4, stained with uranyl acetate, and embedded in Vestopal for electron microscopy. The cell wall was found to be a membranous structure 100 Å thick. A double nuclear membrane, nucleolus, and many darkly staining bodies were observed in the nucleus. Cells contained ribosomes and elaborate Golgi bodies, but no well developed endoplasmic reticulum. The numerous mitochondria typically had well-defined cristae running longitudinally in the mitochondrion. Two bodies of unknown function were observed, one sometimes seen to surround mitochondria, the other bounded by a double membrane. A model of the reservoir structure of the euglenoids is presented, based on observations of the reservoir of A. longa and on published data from Euglena gracilis and E. viridis.

Notizen: SYNOPSIS. Two new dinoflagellates, isolated from Long Island Sound and maintained axenically, are described. Gyrodinium instriatum n. sp. changes shape and size as cultures age. Glenodinium halli n. sp. is a delicately-armored form whose plate structure differs slightly from the present diagnosis of the genus, but not sufficiently like any other genus in morphology or life history for inclusion elsewhere. In G. halli the size of the motile form and predominance of motile or vegetative stages are nutrient dependent. Both dinoflagellates illustrate the need for morphological descriptions based upon continuous culture methods in defined media.

Notizen: SYNOPSIS. The regeneration of three species of Blepharisma—americanum, undulans and japonicum (grown in conslant yellow light in a constant-temperature room at 25d̀C) from specimens of which the hypostome had been removed, was studied under a variety of conditions. The reliability of the methods was checked by an extensive series of experiments with B. americanum and B. japonicum under normal conditions. The time of regeneration of 50% of the individuals was taken as a convenient means for comparing action of various agents. No diurnal rhythm of rate of regeneration was observed. Regeneration is readily affected by the state of nutrition of the cells, starved ones regenerating more slowly than well-fed ones. Regeneration is accelerated by maintaining the cells at 30d̀ but retarded at 35d̀. Even brief exposures to 40d̀ may retard regeneration. Regeneration is slowed by maintenance at temperatures below 25d̀, and stopped at 10d̀. Cut Blepharisma placed at 5d̀ lose pigment in a “shock” reaction and many die. The injury is more marked in lettuce medium than in balanced salt solution. Between 13 and 30d̀ the rate of regeneration increases with rise in temperature, the Q10′s for the ranges 13 to 18d̀, 18 to 25d̀ and 25 to 30d̀ being, respectively, 6.92, 3.93 and 1.56. The effect of temperature upon division of Blepharisma was found to be similarly sensitive to temperature, the Q10's for the ranges 13 to 18d̀, 18 to 25d̀ and 25 to 30d̀ being 3.87, 2.92 and 1.59, respectively. High and low temperature limits for division were also found to be similar to those for regeneration. Preliminary evidence indicates some degree of thermal adaptation in Blepharisma to both higher and lower temperatures than those usually tolerated. The studies indicate a general similarity in sensitivity of regeneration and division to environmental influences in the various races of the species studied, with some individual variations.

Notizen: SYNOPSIS. Two spectrally different cytochromes, referred to as cytochrome-552 and -556 were isolated from Euglena gracilis (Z) grown under different environmental conditions. Their presence or absence was followed during the dark↔ light adaptation, and their concentrations calculated from spectral data. These studies indicate that cytochrome-552 is directly dependent on chlorophyll and photosynthesis, whereas cytochrome-556 is found in all euglenas in a constant amount, and is not dependent on photosynthesis. These cytochromes were further purified to determine differences if any in their physical-chemical properties. The apparent molecular weight calculated from the sedimentation constants is of the order of 11,000 for cytochrome-552, and of the order of 13,000 for cytochrome-556. The electrophoretic mobility shows that cytochrome-552 migrates towards the anode with a mobility depending on pH from 2.5–7.9 cm2/volt/sec. The oxidation-reduction potential for cytochrome-552 is of the order of +0.38 volts, and for cytochrome-556 is of the order of +0.32 volts. These and the other data are compared to similar cytochromes that have been isolated from bacteria, algae, higher plants, and animal cells.

Notizen: SYNOPSIS. The family Glenodiniaceae is abolished because advances in axenic culture and microscopy invalidate its original description. Its 3 genera are removed to the Peridiniaceae. Taxonomic criteria of families and genera concerned are discussed, and morphological studies of Glenodinium foliaceum under phase-contrast and polarization microscopy are reported and illustrated by photomicrographs. Evidence for G. foliaceum being a species intermediate between freshwater and marine dinoflagellates came from morphological and physiological studies. G. foliaceum responded to both inorganic and organic PO4 and NO3 sources. NH4 was toxic. Urea toxicity was due to breakdown of urea on autoclaving. Methionine was not utilized. Proline was toxic. B12 was essential. G. foliaceum culture characteristics and polysaccharide production are reported.

Notizen: SYNOPSIS. Blepharisma undulans, a purple-coloured ciliate protozoan, contains pigment granules in the ectoplasm. Treating the cells with 0.9% NaCl extruded the pigment into the medium without injury to the cells. The extrusion was instantaneous and with a single treatment about 35% of the total pigment oozed out. The pigment in the cells as well as in the saline extract was found to be associated with proteins and particulate fractions. The protozoa regenerated the pigment when transferred to culture fluid but not in dilute solution of saline, where they continued to live without regenerating the pigment. In addition to NaCl, sulphates of monovalent and divalent cations and calcium-binding agents induced the extrusion, which, however, was prevented by calcium in all cases. It is proposed that the removal of calcium from the outer membrane by chemicals disintegrates the pellicle and produces the extrusion, since a majority of the pigment granules are in the subpellicular layers of the cell.

Notizen: SYNOPSIS. Four new genera of Foraminiferida are described. Phlegeria, type species P. hyalina sp. nov. and Tomaculoides, type species T. lucidum sp. nov. belong to the family Glandulinidae, and both were obtained from the Gulf of Mexico. Francesita, type species Virgulina ? advena Cusbman is found in the North Atlantic and the Gulf of Mexico, and belongs to the Caucasinidae. Montfortella, type species M. bramlettei sp. nov. occurs in Pleistocene strata and is living on the coast of California, and belongs to the Cibicididae.