bluuebunny/crossref_metadata_2025 huggingface dataset:
Uniform Terminology for the Protozoan Subphylum Apicomplexa*
Authors: LEVINE NORMAN D.
Published: May 2007

SYNOPSIS. Uniform names for the stages, processes and structures of apicomplexan protozoa are proposed and defined, and names that should be superseded are listed. The same names are used for the same stages of all members of the group. Gregarines are designated as either septate or aseptate rather than as polycystid or monocystid. The gregarine stage often called a sporadin is recognized for what it is, a gamont. The cyst formed around 2 gregarine gamonts in which zygotes are formed is a gametocyst; it contains oocysts which in turn contain sporozoites. The term “spore” is inappropriate for these oocysts. The apical complex includes the polar ring, conoid, rhoptries, micronemes and subpellicular tubules. The gregarine “pseudocyst” is actually a gametocyst residuum. The term micropore is preferred to cytostome for the apicomplexan structure, since it is visible only with the electron microscope.
Malaria parasites (Plasmodium lophurae) Developing Extracellularly in vitro: Incorporation of Labeled Precursors*
Authors: TRAGER WILLIAM
Published: May 2007

SYNOPSIS. P. lophurae were removed from their host duck erythrocytes and incubated in vitro in certain modifications of the red cell extract medium previously described. The extent of incorporation, into material precipitable with trichloracetic acid, of 14C‐labeled precursors supplied after 15–16 hr of incubation, was determined and compared with effects on structure of the parasites. A decreased concentration of erythrocyte extract, which always resulted in increased numbers of degenerate parasites and decreased development to multinucleate forms, also decreased the incorporation of methionine‐methyl‐14C and orotic‐acid‐6‐14C. It did not affect incorporation of proline‐U‐14C or of choline‐1,2‐14C. With a 1/3rd strength red cell extract, omission of coenzyme A, which increased the proportion of degenerate parasites and usually decreased the multinucleate forms, decreased the incorporation of all 4 substrates, in keeping with the inability of the parasites to synthesize CoA. On the other hand, omission of ATP and pyruvate, which had an even greater deleterious effect on structure of the parasites than omission of CoA, had no effect on incorporation of methionine or orotic acid and probably none on that of choline. Incorporation of adenine was reduced in presence of ATP or AMP, suggesting competition at an uptake site. Incorporation of proline, however, was higher with ATP and pyruvate present, in keeping with the better development of the extracellular parasites. The uptake of proline may depend on an ATPase in the outer of the 2 membranes surrounding the parasite.
New Species ofEimeria(Protozoa: Eimeriidae) from Malaysian Squirrels*
Authors: COLLEY FREDRICK C. , MULLIN STEVEN W.
Published: May 2007

SYNOPSIS.In a survey of 520 squirrels of 19 species from Malaysia, 6 new species ofEimeriawere found. Three are described from the subfamily Petauristinae:E. kylopetisn. sp. from the red‐cheeked flying squirrelHylopetes spadiceus; E. aeromysisn. sp. from the large black flying squirrelAeromys tephromelas; E. malayensisn. sp. from the spotted giant flying squirrelPetaurista elegans. Three are described from the subfamily Sciurinae:E. hippurin. sp. from the horse‐tailed squirrelSundasciurus hippurus; andE. notatiandE. pahangin. spp. from the plantain squirrelCallosciurus notatus.
The Effects of Antilymphocytic Serum (ALS) on Trypanosoma lewisi Infection
Authors: TAWIL A. , DUSANIC D. G.
Published: May 2007

SYNOPSIS. ALS was produced in rabbits immunized with cells collected from spleens and mesenteric lymph nodes of normal female Holtzman rats. The ALS was pooled and leucoagglutination tests were performed to determine the ability of the antiserum to agglutinate rat white blood cells in vitro. ALS employed in the study had a titer of 1 :512.

Treatment of rats with ALS prior to and during Trypanosoma lewisi infection resulted in suppression of the immune response. Ablastin production was inhibited. The numbers of dividing forms of the parasites were higher in ALS‐treated rats during the course of infection than in controls injected with saline or normal rabbit serum. ALS‐treated rats continued to have a higher parasitemia than the controls and died 5–12 days post‐infection. Hematocrit readings were lower in the ALS‐treated rats infected with T. lewisi than in rats infected with T. lewisi or normal animals treated with ALS.
Incorporation of Precursors into Toxoplasma DNA
Authors: PERROTTO JOSEPH , KEISTER DAVID B. , GELDERMAN ALBERT H.
Published: May 2007

SYNOPSIS. DNA synthesis of Toxoplasma gondii differs from that of other obligate intracellular parasites in that the parasite can synthesize DNA independently of the host cell and can incorporate preformed pyrimidines as well as pyrimidine precursors. However, pyrimidine precursors such as orotic acid are preferentially utilized over preformed pyrimidines such as thymidine. There is little apparent utilization of purine precursors.
Ethionine and Methionine Metabolism by the Chrysomonad Flagellate Ochromonas danica
Authors: HOCHBERG A. , RAHAT M.
Published: May 2007

SYNOPSIS. Growth of Ochromonas danica is competitively inhibited by ethionine. Inhibition can be reversed by methionine. Inhibition indexes of the effect of ethionine on growth and methionine incorporation into proteins are 1 and 4, respectively. Inside the cell, methionine is partially de‐methylated and metabolized to form cysteine. Ethionine is partially de‐ethylated, and the homocysteine moiety is either re‐methylated to form methionine or further metabolized to form cysteine. Ethionine is also incorporated into proteins of O. danica. The kind of metabolic interference, expressed by inhibition of growth, and correlated with incorporation of ethionine, is yet unknown.
A Redescription of Conchophthirus curtus Engelmann, 1862 (Protozoa, Ciliatea)1
Authors: ANTIPA GREGORY A. , SMALL EUGENE B.
Published: May 2007

SYNOPSIS. The structure of Conchophthirus curtus is described in detail, based on observations by light microscopy, transmission electron microscopy and scanning electron microscopy. Characters of taxonomic importance are described from study of specimens representative of populations of the ciliate collected from 5 localities in Illinois. Variations within and between populations are indicated. New observations include a thoro description of the buccal cavity with its 3 polykineties, a haplokinety, and a deep kinetosomal unit. The somatic ciliature is differentiated into locomotor, thigmotactic, vestibular and caudal regions. In discussion of the systematic position of Conchophthirus, critical review of its past assignments is included; and comments on both the higher and lower levels of taxonomy of the “thigmotrichs” and their relatives are offered.
Eimeria kinsellai sp. n. (Protozoa: Eimeriidae) in a Marsh Rice Rat Oryzomys palustris from Florida*
Authors: BARNARD WILLIAM P. , ERNST JOHN V. , ROPER RICHARD A.
Published: May 2007

SYNOPSIS. Eimeria kinsellai sp. n. is described from the marsh rice rat Oryzomys palustris from Florida. Its ellipsoidal oocysts were 23–31 by 15–19 μ (mean 26.7 by 16.9 μ). One to four polar granules were present but an oocyst residuum was absent. The sporocysts were 12–15 by 7–9 μ (mean 13.9 by 8.1 μ), and sporocyst residua were present.
The Ultrastructure of Encephalitozoon cuniculi (Microsporida, Nosematidae) and its Taxonomic Significance*
Authors: SPRAGUE VICTOR , VERNICK SANFORD H.
Published: May 2007

SYNOPSIS. This study augments our knowledge of several ultrastructural features of Encephalitozoon cuniculi and provides evidence that this species is disporous. We support Cali's view that Encephalitozoon is distinct from Nosema and should be treated as a valid genus. We compare these with 2 other disporous genera, Glugea and Perezia, and conclude that Glugea is also distinct but Perezia is a junior synonym of Nosema.
An Electron Microscopic Study of the Bipolar Bodies in Crithidia oncopelti
Authors: GUTTERIDGE W. E. , MACADAM R. F.
Published: May 2007

SYNOPSIS. An electron microscopic study of the structure of the flagellate Crithidia oncopelti was carried out with particular reference to the nature of the bipolar body which occurs in the organism. Apart from the bipolar body, the fine structure of C. oncopelti is similar to that of the related flagellate, C. fasciculata. The bipolar body is typically a sausage‐shaped organelle limited by 2 unit membranes. Outpouchings of these membranes into the cytoplasm of C. oncopelti were found, along with a constant absence of (a) ribosomes on the outer aspect of the external of the 2 membranes, (b) structures analogous to nuclear pores and (c) an internal structure analogous to a nucleolus. It is concluded that the balance of structural and biochemical evidence favors the idea that the bipolar body is a bacterial protoplast rather than a 2nd nucleus.
Revision of the Order Hypotrichida (Ciliophora, Protozoa)1
Authors: BORRO ARTHUR C.
Published: May 2007

SYNOPSIS. Nearly 400 species of hypotrichs have been described during the last 100 years, but their classification does not reflect their most probable phylogenetic relationships. Recent developments in our understanding of structural and morphogenetic variation now allow for critical evaluation of descriptions of species, explicit definitions of genera, and assignment of genera to families. Following a historical review of classification schemes used previously, morphogenetic bases are given for revisions at the family level, based on a standardized terminology of structural features. The 6 families Urostylidae (9 genera), Psilotrichidae (3 genera), Holostichidae (7 genera), Spirofilidae (7 genera), Oxytrichidae (14 genera), and Euplotidae (11 genera) are now recognized. The suborders erected by Fauré‐Fremiet in 1961 are not recognized in this revision.

Revision at the genus and species levels is based on the known limits of structural variation as well as decisions relative to synonyms and homonyms. Some described species are excluded because they are insufficiently described or interpretable as distorted specimens of unknown systematic position. New genera Paraurostyla n. g. and Pseudourostyla n. g. are proposed. The new names Spiratella and Psammomitra are proposed as replacement names for Spiretta and Micromitra which must fall as junior homonyms. All families and genera are diagnosed and illustrated, and synonymies are listed for each species. The revision recognizes 310 species distributed among 51 genera and 6 families.
Responses of Paramecium to Temperature Change
Authors: TAWADA K. , OOSAWA F.
Published: May 2007

SYNOPSIS. The effect of temperature on the swimming velocity of Paramecium was investigated. When paramecia cultured at 25 C were transferred to various temperatures, their swimming velocity was increased immediately and then decreased exponentially with time to a new steady velocity. The relaxation time was about 1 min, independent of the new temperature. At a constant temperature the steady velocity was inversely proportional to viscosity. The velocity acceleration was observed when the sudden temperature change was larger than ± 1 C. Its magnitude became constant when the temperature change was greater than several degrees. The steady velocity as a function of temperature had a sharp maximum at the culture temperature and decreased on both sides of this temperature. Incubation of paramecia at 30 C for several hr after cultivation at 25 C shifted the maximum temperature of the steady velocity to 30 C. The temperature at which paramecia gathered in a temperature gradient cell correlated closely with the temperature of the maximum steady velocity.
An Ultrastructural Comparison of Euglena gracilis Klebs, Bleached Euglena and Astasia longa Pringsheim
Authors: ROGERS TOM D. , SCHOLES VERNON E. , SCHLICHTING H. E.
Published: May 2007

SYNOPSIS. Some of the cytologic features of Euglena gracilis Klebs, Euglena gracilis var. bacillaris Gross (colorless), and Astasia longa Pringsheim were compared in an electron‐microscope study. E. gracilis was readily differentiated from the colorless forms by the presence of chloroplasts. The 2 colorless forms were structurally similar; however, it was possible to differentiate bleached Euglena from Astasia longa by the presence of irregular plate‐like aggregates of paramylum in the former; similar forms of paramylum were not seen in chloroplast‐containing E. gracilis or in A. longa.
Cyst‐Induced Toxoplasmosis in Cats*
Authors: DUBEY J. P. , FRENKEL J. K.
Published: May 2007

SYNOPSIS. The life cycle of Toxoplasma gondii is described from cats orally inoculated with Toxoplasma cysts. Five new structural stages of Toxoplasma designated as “types” A‐E were found in the epithelial cells of the small and large intestine. Type A is the smallest of all 5 intestinal Toxoplasma types. It occurs as collections of 2‐3 organisms in the jejunum 12–18 hr after infection. Type B organisms are characterized by a centrally located nucleus, a prominent nucleolus and dark blue cytoplasm giving rise to the appearance of bipolar staining with Giemsa. Type B occurs 12–54 hr after infection and appears to divide by simple endodyogeny and by multiple endodyogeny (endopolygeny). Type C organisms are elongate with subterminal nuclei and strongly PAS‐positive cytoplasm. They occur at 24–54 hr and divide by schizogony. Type D organisms are smaller than type C and contain only a few PAS‐positive granules. They occur from 32 hr to 15 days after inoculation and account for over 90% of all parasites in the small intestine during this time. Three subtypes divide by endodyogeny, schizogony and by splitting of their merozoites from the main nucleated mass without leaving a residual body. Type E organisms resemble one of the subtype D which divide by schizogony, but they leave a residual body. They occur from 3–15 days after inoculation.

Gametocytes occur thruout the small intestine but more commonly in the ileum 3‐15 days after infection. Male gametocytes contain on an average of 12 microgametes and comprise 2–4% of the gametocyte population. The prepatent period after cystinduced infection is 3–5 days with the peak oocyst production between 5–8 days and a patent period varying from 7–20 days.

Variable numbers of trophozoites are present in the lamina propria of the small intestine and in the extra‐intestinal tissues within a few hr after inoculation. After 9–10 days cysts were seen in the heart and later in the brain.

The lesions of toxoplasmosis are compared in newborn and weanling kittens and in adult cats after oral and subcutaneous inoculation with cysts. After the ingestion of cysts, newborn kittens developed enteritis, hepatitis, myocarditis, myositis, pneumonitis and encephalitis and were moribund by the 9th day. Kittens aged 2 weeks and older developed enteritis, myocarditis, encephalitis and myositis but often survived; adult cats usually remained asymptomatic. After subcutaneous inoculation of cysts, newborn and weanling kittens died of acute toxoplasmosis with severe pneumonia, myocarditis, encephalitis and hepatitis.
The Physiology of Astrephomene gubernaculifera1
Authors: BROOKS A. E.
Published: May 2007

SYNOPSIS. A comparative physiologic study of 4‐ and 7‐chromosome strains of Astrephomene gubernaculifera was done. The vitamins p‐aminobenzoic acid, nicotinamide, biotin, thiamin HCl and vitamin B12 were tested for their ability to support growth. Only vitamin B12 was required for active growth altho the presence of thiamin HCl was necessary to produce structurally typical colonies. Astrephomene will not grow in the absence of an exogenous source of carbon. Of the 36 carbon sources tested, only pyruvate, butyrate, succinate and acetate permitted active growth. Sodium acetate was the best.

Strains grew within the initial pH range of 5.0–7.5. At pH values above 8.0 growth declined rapidly. When media were buffered with TES (N‐tris [hydroxymethyl]methyl‐2‐aminoethane‐sulfonic acid) at an initial pH of 6.8 growth was enhanced. The organism grew at 15–40 C. Growth in the dark was slightly less than that in the light.
A New Species of Kudoa (Myxosporidea: Chloromyxidae) from the Spot, Leiostomus xanthurus Lacépède, in Clear Lake, Texas*
Authors: JOY JAMES E.
Published: May 2007

SYNOPSIS.
Kudoa branchiata
sp. n. (Myxosporidea: Chloromyxidae) is described from the gills of the marine sciaenid fish, Leiostomus xanthurus Lacépède, from Clear Lake, Texas. Twelve of the 429 hosts examined from 10 September 1970 to 28 April 1971, were infected. Eight of the 12 infected fish were collected in February and March 1971—a period during which only 13% of the total host sample was taken. The mean total length of infected hosts was 149 mm, with a range of 112–185 mm. The mean number of myxosporidean cysts per infected host was 3.5, with a range of 1–11.
Structure of Monocercomonas sp. as Revealed by Electron Microscopy*
Authors: MATTERN CARL F. T. , HONIGBERG B. M. , DANIEL WENDELL A.
Published: May 2007

SYNOPSIS. Monocercomonas shares many fine‐structural features with all other trichomonads. These include the basic arrangement of the kinetosomes as well as of the recurrent and 3 anterior flagella. The pelta‐axostyle complex and the parabasal apparatus, i.e. the Golgi complex and the periodic filaments, also conform to the trichomonad pattern.

Of interest with regard to the crucial evolutionary position of Monocercomonas, considered to represent the most primitive trichomonad type, is the fact that it has some structures in common with other Monocercomonadidae and Trichomonadinae and others in common with Devescovinidae and Tritrichomonadinae. Among the former organelles are the marginal lamella and the costal base, and among the latter, the comb‐like organelle situated between the infrakinetosomal body and parabasal filament 2 as well as the infrakinetosomal body. No traces of either costa or undulating membrane have been noted, but a complex structure homologous to the marginal lamella of Hypotrichomonas and Trichomonadinae is found underlying the short anteriormost portion of the recurrent flagellum that is attached to the body surface.

Observations of sections of selected division stages indicate the potential of parental kinetosomes #1 and #3 to become daughter kinetosome #2.
The Molecular Biology of Euglena gracilis. VII. Inorganic Requirements for a Minimal Culture Medium
Authors: KEMPNER E. S. , MILLER J. H.
Published: May 2007

SYNOPSIS. A culture medium for Euglena gracilis Z has been devised so that each compound is present in minimal concentration to support rapid growth resulting in high cell population. Trace metal contaminations of the glutamic acid substrate were determined by spark‐source mass spectrometry. The incorporation of radio ‐Zn, ‐Mn, ‐Ca, and ‐Cl was followed and the cell composition in this medium was determined.
Growth of an Insect Trypanosomatid at 37 C in a Defined Medium*
Authors: ROITMAN CELINA , ROITMAN ISAAC , de AZEVEDO HELIO PEIXOTO
Published: May 2007

SYNOPSIS. A defined medium for an insect trypanosomatid, “Leptomonas pessoai” (probably a member of the genus Herpetomonas) isolated from the reduviid Zelus leucogrammus, allows growth up to 37 C. No marked differences were evident for growth at 37 C. The requirements for amino acids, vitamins, purine, and hemin, and pH range were like those established for Crithidia fasciculata. Again like C. fasciculata, it remains alive at 4 C for at least 3 months in a çlycerolated defined medium.
Experimental Studies of the Life Cycle of Leucocytozoon simondi in Ducks in Norway*
Authors: EIDE ARNE , FALLIS A. MURRAY
Published: May 2007

SYNOPSIS. Pekin ducks were infected naturally and experimentally. The life cycle of Leucocytozoon simondi was followed in the ducks and the vector, a new species of Simulium, close to Simulium dogieli. The prepatent period in the ducks was 4–5 days and developing megaloschizonts appeared in 6–7 days. Schizonts were found in liver, spleen, brain, and kidney. In the kidneys they were located in the glomeruli. Sporogony in some individuals was completed in 7 days at 13–14 C, other individuals developed more slowly, as ookinetes were found in flies 8 days after feeding. The rapid asexual cycle combined with a sporogonic cycle, in which some ookinetes develop rapidly and others more slowly, favors the maintenance of the parasite in an environment with relatively low daily temperatures. This and the size of the megaloschizonts indicate differences between this strain of the parasite and the one occurring in North America.
Learning in Stentor
Authors: BENNETT DONALD A. , FRANCIS DAVID
Published: May 2007

SYNOPSIS. When placed in a vertical capillary tube of 0.5 mm inner diameter opening at the bottom end into a reservoir, Stentor coeruleus learns to escape; that is, on the 1st trial it takes a long time to find its way out and much less time on the 2nd and succeeding trials. It was found that learning did not occur in a horizontal tube, or in a vertical tube with the open end above, or in tubes of 1 or 2 mm inner diameter. To explain the results it is suggested that the response is actually a delayed geotaxis released only after a definite period of mechanical stimulation from bumping into the walls of the tube. Possibly the phenomenon is related to the process of habituation to mechanical stimuli which has been elucidated by other authors.
Cryopreservation of Pathogenic African Trypanosomes In Situ: Metacyclic and Bloodstream Forms
Authors: DAR F. K. , LIGTHART G. S. , WILSON A. J.
Published: May 2007

SYNOPSIS. Of several methods developed for cryopreservation of Trypanosoma vivax, Trypanosoma congolense, and Trypanosoma brucei metacyclic forms in tsetse fly organs, as well as bloodstream forms in host blood, one proved the most satisfactory. In this method, infected fly proboscises and salivary glands were placed in glass capillary tubes containing fetal calf serum with 8% (v/v) glycerol as the cryoprotectant. The method for bloodstream forms involved the addition of glycerol directly to infected blood, which was then dispensed into capillary tubes. Next the tubes were placed in paper containers inside a glass test tube with a 5 mm thick plasticine jacket. The insulated assembly was suspended in the liquid nitrogen vapor phase in an LR‐35 (Union Carbide) refrigerator for 45 min. Under these conditions, the cooling rate was 2 C/min. The frozen samples were transferred to permanent storage. The viability and infectivity of the preserved organisms were found to be satisfactory upon testing, and no antigenic changes were observed. Laboratory and field applications of the method are discussed.
The Cultivation of Symbiote‐free Marine Ciliates in Axenic Medium
Authors: SOLDO A. T. , MERLIN E. J.
Published: May 2007

SYNOPSIS. Media have been developed for axenic cultivation of 10 strains belonging to 7 species of small marine ciliates. A medium containing cerophyl extract, proteose peptone, trypticase, yeast nucleic acid, biotin, calcium pantothenate folic acid, nicotinamide, pyridoxal HCl, riboflavin, thiamine HCl, and DL‐thioctic acid in sea water supports the growth of Uronema nigricans strains Pc and 34/2, Parauronema virginiatum strains 2/1 and 19/1, Miamiensis avidus strains Ma and 19/3, Miamiensis sp. strain 1/1, a strain of “G” ciliate, and strains 33/8 and 34/7 of 2 unidentified species. By substituting a mixture of asolecithin, cephalin, and Tween 80 for cerophyl in the medium, luxurious growth of all except the strains of the 2 unidentified species can be obtained. A defined medium consisting of 18 amino acids, 5 purine derivatives, 8 vitamins, asolecithin, cephalin, and Tween 80 in synthetic sea water also has been developed for 6 of the strains: M. avidus Ma and 19/3, Miamiensis sp. 1/1, P. virginiatum 2/1 and 19/1, and U. nigricans Pc. In general the ciliates grow best at pH 7.2 in the dark at 27 C in media containing sea water of density = 1.015. Under these conditions maximum populations are reached in 4–5 days and range from several hundred thousand to 3 or 4 × 106 depending upon the strain. Electronmicroscopic observations for the presence of endosymbiotes gave negative results.
A Note on Sporozoa of Undetermined Taxonomic Position in an Armadillo and a Heifer Calf
Authors: LAINSON R.
Published: May 2007

SYNOPSIS

A sporozoan parasite of undetermined taxonomic position is described in the nine‐banded armadillo,Dasypus novemcinctus, from British Honduras, Central America. Schizonts, giving rise to approximately 60 merozoites, are produced in the parenchyma cells of the liver and in the endothelial cells of the brain capillaries: rupture of the schizonts stimulates conspicuous foci of inflammatory response. No sexual stages were observed. A similar parasite is recorded in the lung and liver of a heifer calf,Bos taurus, from England. The possible relationship of these parasites within the Sporozoa is discussed.
Mirex and Aroclor® 1254: Effect on and Accumulation by Tetrahymena pyriformis Strain W*
Authors: COOLEY NELSON R. , KELTNER JAMES M. , FORESTER JERROLD
Published: May 2007

SYNOPSIS

Effects of 2 toxicants, Mirex and Aroclor 1254, on Tetrahymena pyriformis strain W in axenic cultures were investigated. Mirex is a chlorinated hydrocarbon effective against the fire ant, and Aroclor 1254 is a compound structurally related to DDT and used extensively in various industrial processes. Both toxicants reduced growth rates and population densities of T. pyriformis grown at 26 C generally in proportion to concentrations of the chemicals, their effects becoming statistically significant (P < 0.05) at 0.9 μg/liter for Mirex and 1.0 and 10.0 μg/liter for Aroclor 1254. Ciliates exposed to the toxicants for 7 days concentrated Mirex 193 × and Aroclor 60 × as compared to the initial concentrations of these compounds. It is suggested that the chief effect of the 2 toxicants on populations of T. pyriformis and of similarly responding ciliates in nature would be to reduce the availability of these protozoa as food organisms and nutrient regenerators. The ability of the ciliates to concentrate the tested compounds would permit the toxicants to enter into and to be translocated through aquatic food chains. In this manner the compounds could exert toxic effects at higher trophic levels.
The Stability of Cortical Phenotypes in Continuously Growing Cultures of Tetrahymena pyriformis*
Authors: FRANKEL JOSEPH
Published: May 2007

SYNOPSIS

Cortical features were analyzed in successive samples of continuously growing stock cultures of amicronucleate strains GL‐C and GL‐I, and in micronucleate strain WH‐6 (syngen 1, mating type I). Thirteen successive samples of strain GL‐C, representing a time span of 111 months, 5 samples of WH‐6 (43 months) and 2 samples of GL‐I (1 month) were examined. The observed range of commonly expressed ciliary row numbers (corticotypes) was 16–20 rows in strain GL‐C, 15–20 in strain GL‐I, and 16–20 in strain WH‐6. These ranges remained constant through time within each strain. The individual samples each included all or a large part of the total range observed in the strain, but the relative abundances of different corticotypes within this range shifted through time. The shifts appeared random, with no discernible trends.

Mean contractile vacuole pore (CVP) position and number of CVP meridians were assayed in the 2 “GL” strains. Mean CVP position was an apparently stable character, with only slight fluctuations through time, while the distribution of number of CVP meridians was somewhat less constant. The CVP parameters of strains GL‐C and GL‐I were considerably different, and both of these strains were very different from the GL strain which had been studied by Nanney. In fact, these 3 “GL” strains have, among them, virtually the entire gamut of known CVP characteristics. The possible significance of these wide differences among strains presumed to be closely related is considered in the Discussion.
The Fine Structure of the Centriolar Apparatus and Associated Structures in the Flagellates Deltotrichonympha and Koruga. II. Division
Authors: TAMM SIGNHILD , TAMM SIDNEY L.
Published: May 2007

SYNOPSIS. At division of Deltotrichonympha operculata and Koruga bonita from the Australian termite, Mastotermes darwiniensis, the 2 centriolar bodies separate, each becoming a mitotic center. Spindle microtubules develop from the lower end of each centriolar body and radiate towards the elongating nucleus. A new rostrum is formed in association with each centriolar body. Thus, centriolar bodies which lack the structure of typical centrioles can nevertheless function as division centers during mitosis.
The Mode of Attachment of Trypanosoma vivax in the Proboscis of the Tsetse Fly Glossina fuscipes: an Ultrastructural Study of the Epimastigote Stage of the Trypanosome*
Authors: VICKERMAN KEITH
Published: May 2007

SYNOPSIS. The ultrastructure of attached Trypanosoma vivax epimastigote clusters in the proboscis of the tsetse fly Glossina fuscipes is described from electron micrographs of thin sections. Some flagellates are attached directly to the lining of the insect's labrum by their flagella, most of which are aligned along the long axis of the proboscis. Other trypanosomes are attached indirectly, their flagella adhering to those of flagellates which are directly attached. Junctional complexes similar to those described from metazoan epithelia are found on the flagellar membrane. A long zonular hemidesmosome attaches the flagellum to the proboscis wall and a series of closely set macular desmosomes link the flagellar membranes of adjacent flagellates. Unlike the trypomastigote stages of T. vivax, more than one row of macular desmosomes may be present along the flagellum‐body junction of the trypanosome. It is suggested that all these Junctional complexes serve to buttress the flagellate's attachment to its insect host and so maintain anchorage of the parasite during the fly's blood meals. The ability of the flagellum of trypanosomatids to form Junctional complexes may be a factor contributing to their success as parasites, this adaptation enabling them to multiply while attached to host surfaces.
The Enzymic Synthesis of Dihydropteroate and Dihydrofolate by Plasmodium berghei
Authors: FERONE ROBERT
Published: May 2007

SYNOPSIS. Cell‐free extracts of the rodent malaria parasite Plasmodium berghei synthesized dihydropteroate (H2pteroate) and dihydrofolate (H2folate) from 2‐amino‐4‐hydroxy‐6‐hydroxymethyl‐7,8‐dihydropteridine (hydroxymethyldihydropteridine) and p‐aminobenzoate (pAB) or p‐aminobenzoylglutamate (pABG). The reaction was demonstrated also in extracts of Plasmodium gallinaceum, Plasmodium lophurae and Plasmodium knowlesi, by the use of a microbiologic assay method and pABG as cosubstrate.

Some of the properties of the enzymes involved were investigated in P. berghei preparations, utilizing a radioactive assay which measures the conversion of [7‐14C]pAB to [14C]H2pteroate. Apparent Km values of 0.28 μM for [7‐14C]pAB, 0.037 mM for pABG and 0.8 μM for hydroxymethyldihydropteridine were obtained. The reaction had absolute requirements for ATP and Mg++, and was stimulated by dithiothreitol. The enzymes required for the reaction were eluted together from Sephadex G‐200 columns in a molecular weight range of 200,000–250,000. In bacteria hydroxymethyldihydropteridine is converted 1st by a pyrophosphokinase to pyrophosphorylmethyldihydropteridine, and this compound is then condensed with pAB to form H2pteroate by H2pteroate synthetase. Both enzymic activities were demonstrated in P. berghei preparations and separated by DEAE‐Sephadex chromatography.

The enzymic synthesis of H2pteroate by P. berghei is inhibited by several sulfonamides and diaminodiphenylsulfone (DDS). The latter compound is shown to be competitive with pAB, with a Ki value of 0.38 μM; pABG is also a competitive inhibitor. These data establish an enzymic basis of support for the evidence obtained in vivo which indicate that malaria synthesize their folate cofactors de novo. It is suggested that the antimalarial action of sulfonamides and DDS is due to their inhibition of plasmodial H2pteroate synthetase.
Observations on the Host‐Symbiont Relationships of Lagenophrys lunatus Imamura*
Authors: CLAMP JOHN C.
Published: May 2007

SYNOPSIS

An epizoic loricate peritrich, Lagenophrys lunatus Imamura, was found in North Carolina, Virginia, and Maryland on the exoskeleton of the palaemonid shrimp, Palaemonetes pugio, P. intermedius, P. vulgaris, P. paludosus, and Macrobrachium ohione. L. lunatus prefers to attach onto or near the appendages of the host where water movement over the exoskeleton is strongest. The symbionts depend for their food on particles of the host's food and phytoplankton swept to them by these water currents. They attach to other areas of the exoskeleton only when the preferred areas are filled. Trophic individuals are stimulated to undergo a special type of division in advance of the molt of the host that results in the evacuation from the old exoskeleton. Conjugation occurs en masse and has only been observed during molting of the host.
Macro‐ and Micronuclei of Tetrahymena pyriformis: A Model System for Studying the Structure and Function of Eukaryotic Nuclei*†
Authors: GOROVSKY MARTIN A.
Published: May 2007

SYNOPSIS

The macro‐ and micronucleus of Tetrahymena pyriformis are formed from a common diploid synkaryon during conjugation. Shortly after the 2nd postzygotic division, distinct morphologic and physiologic differences develop between the 2 nuclei. Micronuclei remain small, presumably diploid, and electronmicroscopic observations indicate that micronuclear DNA is contained in a dense, fibrous, chromosome‐like coil. Macronuclei contain considerably more DNA than micronuclei, and the DNA of the macronucleus is found largely in the chromatin bodies typical of ciliate nuclei. The functional differences between macro‐ and micronuclei in vegetative cells also are striking. The template activity of DNA in the micronucleus is highly restricted compared to that in the macronucleus. Micronuclei synthesize and contain little RNA, and do not contain either nucleoli or ribonucleoprotein granules. Macronuclei, on the other hand, synthesize and contain large amounts of RNA and have many nucleoli and ribonucleoprotein granules. Macro‐ and micronuclei also have distinct differences in the timing of DNA synthesis during the cell cycle and in the timing and mechanism of nuclear division. Finally, during conjugation the macronucleus becomes pycnotic and disappears while the micronucleus undergoes meiosis and fertilization, ultimately giving rise to new macro‐ and new micronuclei. In short, the macro‐ and micronuclei of Tetrahymena provide an excellent system for studying the molecular mechanisms by which the same (or related) genetic information is maintained in different structural and functional states.

Methods have been devised to isolate and purify macro‐ and micronuclei of Tetrahymena in the hope of correlating differences in the nucleoprotein composition of these nuclei with differences in their structure and function. The DNAs of macro‐ and micronuclei have been found to differ markedly in their content of a methylated base, N6‐methyl adenine, and major differences in the histones of the 2 nuclei have been observed. Macronuclei contain histones similar to those found in vertebrate nuclei, while 2 major histone fractions seem to be missing in micronuclei. In addition, histone fraction F2A1 which is found in multiple, acetylated forms in macronuclei, is present only as a single, unacetylated form in micronuclei.
The Role of the Contractile Vacuole in the Osmoregulation of Tetrahymena pyriformis*
Authors: RIFKIN† JARED L.
Published: May 2007

SYNOPSIS

The relationship of cell size and contractile vacuole efflux to osmotic stress was studied in Tetrahymena pyriformis strain W, after transfer into fresh solutions iso‐ or hypoosmotic to the growth medium. Microscopic measurements of the cell and contractile vacuole dimensions, made with an image‐sharing ocular at 27 C, allowed the calculation of the cell size and shape and the vacuolar efflux rate which provide a measure of osmoregulation. The contractile vacuole cycles have no homeostatic oscillations. In 0.03–0.10 osmolar solutions, the cell size and shape are constant while the vacuolar efflux rate has an inverse linear dependence upon extracellular osmolarity. Regression analyses indicate that for cells with systole faster than 0.1 sec (the major part of the population), it is only the final diastolic volume of the contractile vacuole that is related to osmotic stress while the frequency of systole is independent of osmotic stress and has a constant period of 7.7 ± 0.2 sec. Therefore, osmotic stress upon Tetrahymena is regulated by a corresponding change in the filling rate of its contractile vacuole to allow an unaltered cell size and shape. Kinetic measurements of vacuoles during diastole fit the model (dV/dt = K1‐K2A), where (dV/dt) is the vacuolar filling rate and (A) is the vacuolar surface area. This dependence of vacuolar volume upon its surface area may be ascribed either to elastic components of the vacuolar membrane or to an increasing leakiness of this membrane during diastole. Mitochondrial inhibitors were used to observe the energy requirements of vacuolar operation and of intracellular secretion of water.
Phototaxis: Isolation of Mutant Strains of Chlamydomonas reinhardi with Reversed Sign of Response*†
Authors: HUDOCK G. A. , HUDOCK M. O.
Published: May 2007

SYNOPSIS

Three mutant strains of Chlamydomonas reinhardi were isolated which are negatively phototactic under all conditions tested. Tetrad analysis indicated that these represent three separate, nuclear mutations. Two mutant genes are linked; the third is on a separate chromosome. At least two of the loci appear relatively far from their centromere(s).
A Marine Euplotes (Ciliophora, Hypotrichida) with Reduced Number of Prezygotic Micronuclear Divisions
Authors: LUEKEN WOLFGANG W.
Published: May 2007

SYNOPSIS

In contradistinction to the pattern of 3 prezygotic micronuclear divisions found in 10 species of Euplotes, a marine species resembling Euplotes crassus in structure, has only 2 divisions. This atypical division pattern was observed in all matings involving the 4 available mating types. The critical stages of the nuclear events are demonstrated by using special strains having the micronuclear DNA content and chromosome number only 1/2 the normal values. The employment of such strains facilitates differentiation between the stationary and migratory pronuclei in a given conjugant and determination of the times of conclusion of prezygotic divisions and of the pronuclear exchange.
Eimeria indianensis sp. n. and an Isospora sp. from the Opossum Didelphis virginiana (Kerr)*
Authors: JOSEPH THOMAS
Published: May 2007

SYNOPSIS

Two of 15 road‐killed opossums examined for coccidia were found to be infected with a hitherto undescribed species of Eimeria, herein named Eimeria indianensis. The oocysts were spherical (63%) or slightly subspherical (37%) with a double‐layered wall. The outer layer was ∼1.5 μm thick, yellowish, striated, and appeared rough and pitted on the surface. A micropyle was absent. The spherical oocysts were 16.3 (13–18) μm in diameter; the subspherical ones, 17.6 (15–18) × 16.4 (14–17) μm. The sporocysts measured 9.1 (8–10) × 6.2 (6–7) μm and contained a granular residuum. The sporozoites were elongate, measuring 13.4 (13–15) × 1.8 (1.6‐2.0) μm; no refractile globules were seen. The prepatent period was 10 days and the patent period ranged from 9–15 days.

A few oocysts of an Isospora sp. were present in one opossum. It was not possible to confirm whether they were specifically of the opossum or of spurious origin.
The Fine Structure of the Phoront of the Apostomatous Ciliate, Hyalophysa chattoni*
Authors: BRADBURY PHYLLIS CLARKE
Published: May 2007

SYNOPSIS

The phoront of the apostomatous ciliate, Hyalophysa chattoni, is an encysted stage that is carried on the exoskeleton of its crustacean host until the ecdysis of the host. At molting the phoront rapidly metamorphoses to the feeding stage, excysts, and immediately begins to feed on exuvial fluid trapped in the cast‐off exoskeleton. The fine structure of the resting phoront resembles that of the preceding migratory stage, the tomite. A prominent ventral tuft of cilia, the ogival field, has vanished, and the trichocysts that paralleled the kinetics have disappeared. The dense inclusion bodies that were concentrated around the mouth and falciform fields have dispersed and greatly decreased in number. The cytoplasm and its membranous organelles do not appear visibly condensed or altered from the preceding stage in the life cycle. The phoront is merely quiescent instead of dormant.

Unlike the few ciliate cysts previously examined by electron microscopy, the phoront's cyst is not divisible into separable layers. It resembles the loricae of certain suctoria in being formed principally of a fibrous substance, the outer surface of which has a paracrystalline pattern. The peduncle attaching the cyst to the crab's gill is a continuation of the cyst wall although its structure is somewhat modified.

The most conspicuous innovation in the phoront's fine structure is the massive tracts of microtubules that run longitudinally through the macronucleus. The microtubules are in intimate contact with Feulgen‐positive chromatin masses which are crowded toward the periphery of the macronucleus.
Lysosomal Physiology in Tetrahymena. II. Effect of Culture Age and Temperature on the Extracellular Release of 3 Acid Hydrolases*
Authors: ROTHSTEIN THOMAS L. , BLUM J. J.
Published: May 2007

SYNOPSIS

Tetrahymena cultures were grown from a single inoculum and collected on 3 successive days corresponding to the log, transitional, and early stationary phases of growth. Cells were washed and incubated for 5 hr in a dilute salt solution. Intra‐ and extracellular activities of acid phosphatase, α‐glucosidase, and ribonuclease were assayed, and extracellular activities corrected for proteolytic degradation. A marked increase in the cellular content of acid phosphatase and significant decreases in α‐glucosidase and ribonuclease occurred with advancing culture age. The intracellular changes in enzyme activities during incubation were roughly similar for cells of all ages. Protein content did not change appreciably during incubation. Extracellular A255 release, monitored as an indication of the loss of RNA breakdown products, was at a minimum during incubation of transition cells. Significant quantities of all 3 acid hydrolases were released from cells of all ages except for ribonuclease from transition cells.

The release of acid phosphatase and α‐glucosidase was approximately proportional to the initial cellular content of these enzymes for cells of different ages and in log cells the effect of temperature on the rates of release was described by the Arrhenius equation. Release of ribonuclease, however, was not proportional to its intracellular content nor did it vary with temperature according to the Arrhenius equation. The results suggest that acid phosphatase and α‐glucosidase are released via a first‐order process.
Results of Blood Transfusions from Donor Rabbits Infected with Eimeria stiedai to Recipient Coccidia‐free Rabbits*
Authors: FITZGERALD PAUL R.
Published: May 2007

SYNOPSIS

Blood, withdrawn by heart puncture, from donor rabbits infected with Eimeria stiedai, was transfused by heart puncture, to uninfected recipient rabbits. Fifty‐nine of 76 young coccidia‐free recipients, given heparinized whole blood, erythrocytes or leucocytes from donors orally inoculated up to 27 days earlier, developed E. stiedai infections.
Labeling of Crithidia fasciculata DNA with [3H]Thymidine
Authors: SIMPSON AGDA M. , SIMPSON LARRY
Published: May 2007

SYNOPSIS

Attempts at continuous labeling of Crithidia fasciculata DNA with [3H]thymidine led to a pulse‐chase situation due to a cell‐mediated conversion of thymidine to thymine in the medium. The uptake of thymine was slow compared to that of thymidine. Neither the addition of deoxyadenosine nor the sequential addition of several aliquots of [3H]thymidine had an effect on the pattern of labeling.
Seven New Eimeria spp. (Protozoa, Coccidia) from Freshwater Fishes of Canada*
Authors: MOLNAR KALMAN , HANEK GEORGE
Published: May 2007

SYNOPSIS

Seven new species of Eimeria are described and figured from the freshwater fishes of Ontario and Quebec, Canada. They are Eimeria catostomi sp. n. and E. fernandoae sp. n. from Catostomus commersoni (Lacépède), E. etheostomae sp. n. from Etheostoma exile (Girard), E. hoffmani sp. n. from Umbra limi (Kirtland), E. micropteri sp. n. from Micropterus dolomieui Lacépède E. pungitii sp. n. from Pungitius pungitius (Linnaeus), and E. salvelini sp. n. from Salvelinus fontinalis (Mitchill). Furthermore, 2 new host records and 2 new distribution records for North America are reported for E. anguillae Léger & Hollande, 1922 and E. truttae Léger & Hesse, 1919 respectively. Finally, morphologically similar oocysts found in various cyprinids are regarded as belonging to E. iroquoina Molnar & Fernando, 1974.
Studies on the Motility of Plasmodium Sporozoites*
Authors: VANDERBERG JEROME P.
Published: May 2007

SYNOPSIS

Albumin was found to have a striking stimulatory effect on motility of Plasmodium sporozoites, while serum globulins had an inhibitory effect. Albumin also preserved viability of sporozoites in vitro at 4 C for several days. P. berghei, P. cynomolgi, and P. falciparum sporozoites each had a distinct and characteristic type of motility. P. berghei sporozoites from oocysts had a different type of motility from that of salivary gland sporozoites, each type presumably associated with different invasive capacities at different times during the life cycle of the parasite. This change in sporozoite motility during development was also associated with other physiologic developmental changes in the sporozoite. The degree of motility of a given pool of sporozoites was to some degree associated with other parameters of metabolic activity of these sporozoites, i.e. infectivity, immunogenicity, and secretory activity. Secretions of the rhoptry‐microneme complex may play a role in sporozoite motility.
Antigens and Antigenic Variability of the African Trypanosomes*†
Authors: SEED JOHN RICHARD
Published: May 2007

SYNOPSIS. The recent literature on the physical, chemical and biological characterization of antigens from the African trypanosomes is reviewed. The antigens are divided into three major groups: a) variant‐specific antigens, b) common antigens, and c) host‐like antigens. The variant‐specific antigen(s) are relatively small molecular weight proteins located on the surface of the trypanosome, and are involved in protection and agglutination. It is suggested that there is more than a single variant‐specific antigen on the cell surface. In contrast, the common antigens are internal or somatic antigens which are believed to have structural or enzymatic functions but are not involved in either protection or agglutination. In addition, evidence is also presented which suggests that there are host‐like antigens within the surface coat and/or membranes of the trypanosomes. The importance of these three groups of antigens, and the mechanis(s) of antigenic variation are discussed in relationship to the immune response of the host to the African trypanosomes. Several possible approaches for future investigations are described.
“Trace Metabolites”–Effect of High Concentrations on Leishmania tarentolae Promastigotes*
Authors: SHEETS ELOISE G. , KRASSNER STUART M.
Published: May 2007

SYNOPSIS. Relatively high concentrations (10–100 μM) of chromate, selenate, and vanadate ions accelerated growth of Leishmania tarentolae in a chemically defined medium containing taurine as the sole sulfur source. These ions also enhanced the incorporation of [35S]taurine label in whole cell, 10% trichloroacetic acid insoluble, and 10% trichloroacetic acid soluble cell fractions.