The effect of monoterpenes on astaxanthin production by a mutant ofPhaffia rhodozyma

Summary The total pigment and astaxanthin content ofPhaffia rhodozyma increased with increasing concentrations -pinene up to 500 l -pinene/l. Above this concentration the total pigment and astaxanthin content as well as the biomass production decreased. The addition of 500 l -pinene/l increased the total pigment content from 1652 g/g to 2201 g/g and the astaxanthin content from 1554 g/g to 1883 g/g. A sharp decrease in maximum specific growth rate occurred above 150 l -pinene/l.     

In vitro propagation of Glehnia littoralis from shoot-tips

Shoot cultures of Glehnia littoralis F. Schmidt ex Miq. (Umbelliferae) were established by placing shoot tip explants on Linsmaier and Skoog medium with 1 M NAA and 10 M BAP. Shoots were multiplied on the basal medium supplemented with 0.3 M NAA and 3 M BAP and rooted on medium containing either 1 M IBA or 3–10 M IAA. Plantlets survived in pots without any covering. This unique characteristic of the plantlets was ascribed partly to a well-developed cuticle on the surface of the leaf and the small ratio of surface area to fresh weight of a leaf blade in comparison with those of other species whose plantlets needed coverings after potting. The regenerated plantlets were finally transferred to soil.Abbreviations IAA potassium indole-3-acetate - IBA indole-3-butyric acid - IPA indole-3-propionic acid - NAA potassium 1-naphthaleneacetate - 2,4-D sodium 2,4-dichlorophenoxyacetate - BAP 6-benzylaminopurine - 2-iP N⁶-(2-isopentenyl)adenine     

The nutritional status of the apical meristem of Lactuca sativa as affected by NaCl salinization: An electron-probe microanalytic study

A volume of tissue of lettuce (Lactuca sativa L.) plants extending 2 mm basipetally from the apical meristem and including leaf primordia and young expanding leaves was surveyed using electron-probe microanalysis (EPMA) on both frozen-hydrated and freeze-dried samples. This analysis was carried out either 2 or 5 d following NaCl salinization of the medium from the 10 mol · m^–-3 control level up to 80 mol · m^–-3. The objective was the investigation of possible changes in the nutritional status of the apical meristem that might account for some aspects of salt-induced growth inhibition. Sodium and chloride increased significantly in tissues basal to the apical meristem, while both phosphorus and potassium decreased in the same region. These changes were evident in specimens collected just 2 d after the commencement of salinization (20 h after completion of the salinization) and were not exacerbated by an additional 3 d of treatment; they were present in tissue as close as 100 m to the meristem and extending down to 500 m. The apical 10–50 m were relatively protected from both the increase in sodium and chloride and the decrease in phosphorus and potassium that occurred in more basal regions. Young leaves (up to 1.5 mm in length) appear to control their own mineral nutrient levels when challenged by salinization of the medium, presumably because of altered growth. A decrease in the concentration of total Ca as a result of salinization was significant in cells 500 m basal to the meristem, but was evident as a tendency in the data even within the first 50 m. Using an improved automatic method for the analysis of calcium by EPMA, it was found that total Ca was reduced by salinization, especially in basal regions (500 m below the apex) and also in young leaves (1–1.5 mm in length). We suggest that the nutrition of the shoot apical meristem may be disturbed soon after salinization and that the shoot meristem might be the source of a signal to expanding leaves, as well as exerting its own direct influence over leaf emergence.Abbreviation EPMA electron-probe microanalysis This work was supported by U.S. Department of Agriculture grant 87-CRCR-1-2462.     

Osmotic measurements on stomatal cells ofCommelina communis L.

Summary Observations of aperture changes as sucrose is added to the solution bathing epidermal strips ofCommelina communis L. allow calculation of the osmotic changes required to open or close the stomatal pore, for comparison with changes in potassium content. With isolated guard cells, in strips in which all cells other than guard cells have been killed, the internal osmotic changes required are 83 mosmol kg^–1 m^–1 below 10m aperture, 129 mosmol kg^–1 m^–1 in the range 10–15 m, and 180 mosmol kg^–1 m^–1 above 15 m. For opening against subsidiary cell turgor in addition to guard cell turgor, in intact strips with live subsidiary and epidermal cells, these figures should each be increased by about 33 mosmol kg^–1 m^–1. A change in subsidiary cell turgor is magnified in its effects on the water relations of the guard cell by a factor greater than 3.7 for equal changes in the water potential of the two cells, or greater than 4.7 at constant volume of the guard cell.     

The eyes of mesopelagic crustaceans: I. Gennadas sp. (Penaeidae)

Summary The eye of the deep-sea penaeid shrimp Gennadas consists of approximately 700 square ommatidia with a side length of 15 n. It is hemispherical in shape and is located at the end of a 1.5 mm long eye stalk. The cornea is extremely thin, but the crystalline cone is well-developed. A clear zone between dioptric structures and the rhabdom layer is absent. A few pigment granules are found within the basement membrane; otherwise they, too, are absent from the eye of Gennadas. The rhabdom is massive and occupies 50 % of the eye. It consists of orthogonally oriented microvilli (the latter measuring 0.07 m in diameter) and is 75 m long. In cross sections adjacent rhabdoms, all approximately 8 m in diameter, form an almost continuous sheet and leave little space for retinula cell cytoplasm. In spite of a one h exposure to light, rhabdom microvilli show no disintegration or disruption of membranes. Vesicles of various kinds, however, are present in all seven retinula cells near the basement membrane. Bundles of seven axons penetrate the basement membrane. On their way to the lamina they often combine and form larger aggregations.The authors wish to thank the director of the Meat Industry Research Institute in Hamilton and his staff for the use of their electron microscope facilities     

The eyes of mesopelagic crustaceans

Summary In Streetsia challengeri left and right eyes have fused and become a single cylindrical photoreceptor, which occupies the basal half of a forward directed head projection. This unusual compound eye consists of approximately 2500 ommatidia, which are arranged in such a way that the animal has almost circumferential vision, but cannot look ahead or behind. It is thought that the eye operates on light-guide principles, and that the crystalline cones are the major dioptric component. Ommatidia in anterior-posterior rows show a greater overlap of visual fields than dorso-ventrally arranged ommatidia. Cone layer and retinula are separated by a 4 m thick screen-membrane, which contains tiny pigment granules of 0.15 m diameter. Cells of unknown function and origin, containing unusual multitubular organelles, are regularly found near the proximal ends of the crystalline cone threads. The twisted rhabdoms measure 18–20 m in diameter, and consist of microvilli 0.05 m in width, which belong to five retinula cells and which show no trace of disintegration. The position of interommatidial screening pigment, the density of retinula cell vesicles and inclusions, and the narrowness of the perirhabdomal space all suggest that the eyes have been light-adapted at the time of fixation for electron microscopy. The retinula cell nuclei lie on the proximal side of the heavily pigmented basement membrane. A tapetum or basal retinula cells are not developed. It is concluded that the eye optimally combines acuity with sensitivity, and that for distance estimation parallax may be important.Address until January 25th 1978: Scott Base, Ross Dependency, Antarctica (C/-Chief Post Office, Christchurch, New Zealand)     

Histrionicotoxins: Effects on binding of radioligands for sodium,potassium, and calcium channels in brain membranes

A series of eight histrionicotoxins and two synthetic analogs inhibit binding of [³H]batrachotoxinin B to sites on voltage dependent sodium channels in brain membranes. Perhydrohistrionicotoxin (IC₅₀ 0.33 M) and octahydrohistrionicotoxin (IC₅₀ 1.2 M) are comparable in activities to potent local anesthetics. Histrionicotoxin (IC₅₀ 17 M) and the other histrionicotoxins are much less potent. The histrionicotoxins also inhibit binding of [³H]phencyclidine to putative potassium channels in brain membranes. Histrionicotoxin (IC₅₀ 15 M) and the other histrionicotoxins are much more potent than perhydrohistrionicotoxin (IC₅₀ 200 M), but are at least 200-fold less potent than phencyclidine. The histrionicotoxins enhance binding of [³H]nitrendipine to sites on calcium channels in brain membranes, with the exception of perhydrohistrionicotoxin, which inhibits binding. Structure activity relationships at these channel sites and at the sites for noncompetitive blockers on the nicotinic acetylcholine receptor channel (AChR) complex differ. The histrionicotoxins are more potent at the sites on the AChR complex than at sites on other channels with the exception of perhydrohistrionicotoxin, which has comparable potency at the AChR complex and sodium channels.     

Karyometry of nuclei in liver cells

Summary In untreated adult male albino rats nuclear volume and the percentage of binucleate cells were determined in the first layer of hepatocytes adjacent to hepatic venous branches of varying diameters (<40 m, 40 m–80 m, 80 m–120m, 120 m–160 m, >160 m), and in the third and fourth layer of hepatocytes in the remainder of the perivenous parenchyma. In the first layer of hepatocytes adjacent to the vascular structures means of nuclear volume are significantly lower and percentage of binucleate cells significantly higher than in the cells of the remainder of the perivenous parenchyma. Within each area measured distribution curves of nuclear volume classes were homogeneous but showed heterogeneity in comparison with each other. The morphometric data presented in this study strongly support the opinion of the heterogeneity of liver cells in the perivenous zone, as previously postulated on the basis of histochemical investigations.Supported by the Deutsche Forschungsgemeinschaft (Hi 318/2-1)     

Quantitative radioautographic study of intracellular localization of calmodulin antagonist,W-7, in Chinese-hamster ovary cells

Summary The purpose of the present study was to analyse quantitatively the localization of calmodulin antagonist, n-(6-aminohexyl)-5-chloro-1-naphthalene-sulfonamide (W-7) in CHO-Kl cells. The cultured CHO-Kl cells were labelled with 1 (16.7 M), 2 (33.4 M), 5 (83.5 M) and 10 Ci/ml (167 M) tritiated W-7. Some cells were preincubated in 10, 50 and 100 M unlabelled W-7 for 30 min and then labelled with 2 or 5 Ci/ml tritiated W-7 for 1 h. The cells were doubly fixed in glutaraldehyde and osmium-tetroxide solution, and embedded in Epon. For light-microscopic radioautography, 2 m-thick sections were wet mounted with radioautographic emulsion and exposed for 1 month. The radioautograms showed that large numbers of silver grains were mainly localized in the cytoplasm as well as in the nucleus. Quantitative analysis demonstrated that, in both the cytoplasm and nucleus, the number of silver grains was dependent on the concentration of the administered tritiated W-7 and the number was dramatically decreased by the pretreatment of unlabelled W-7. These results show that, in CHO-Kl cells, the W-7 binding sites are saturable. It is concluded that W-7 may get into CHO-Kl cells and be bound to a specific protein that may be calmodulin protein.     

The Effect of Phenylalanine on DOPA Synthesis in PC12 Cells

DOPA synthesis from phenylalanine was studied in PC12 cells incubated with m-hydroxybenzylhydrazine, to inhibit aromatic L-amino acid decarboxylase. DOPA synthesis rose with increasing concentrations of either phenylalanine or tyrosine; maximal rates (~55 pmol/min/mg protein for tyrosine; ~40 pmol/min/mg protein for phenylalanine) occurred at a medium concentration of ~10 M for either amino acid. The K_m for either amino acid was about 1 M (medium concentration). At tyrosine concentrations above 30 M, DOPA synthesis declined; inhibition was observed at higher concentrations for phenylalanine (300 M). These effects were most notable in the presence of 56 mM potassium. Measurements of intracellular phenylalanine and tyrosine suggested the K_m for either amino acid is 20–30 M; maximal synthesis occurred at 120–140 M. In the presence of both phenylalanine and tyrosine, DOPA synthesis was inhibited by phenylalanine only at a high medium concentration (1000 M), regardless of medium tyrosine concentration. The inhibition of DOPA synthesis by high medium tyrosine concentrations was antagonized by high medium phenylalanine concentrations (100, 1000 M). Together, the findings indicate that for PC12 cells, phenylalanine can be a significant substrate for tyrosine hydroxylase, is a relatively weak inhibitor of the enzyme, and at high concentrations can antagonize substrate inhibition by tyrosine.     

Uptake and Retention of Selenite and Selenomethionine in cultured K-562 cells

The selenium uptake and retention have been studied in K-562 cells exposed to selenite or selenomethionine. In the uptake experiments the cells were exposed to two doses of selenite (5 or 50 M) or selenomethionine (10 or 50 M). In the retention study the cells were treated for 2 h with the above mentioned doses of the selenocompounds before being observed at different times. The selenium uptake in cells exposed to selenite 5 M began to saturate at 8 h, but increased again between 48 and 96 h. In cells exposed to selenite 50 M the selenium uptake never reached a maximum, however, at 48 and 96 h the cell viability decreased strongly. The two doses of selenite showed different retention patterns, with a relatively small cellular decrease of selenium after treatment with selenite 5 M compared to treatment with 50 M of selenite. The selenium uptake in cells exposed to selenomethionine 10 M or selenomethionine 50 M began to saturate at 24 h and 48 h, respectively. The retention patterns were similar for both selenomethionine doses with a continuous decrease of the selenium concentration during the whole observation period. The results indicated a more controlled uptake and retention pattern of selenomethionine compared to selenite.     

Fine structure studies of the ocelli of Polyorchis penicillatus (Hydrozoa,Anthomedusae) and their connection with the nerve ring

Summary The fine structure of the small compact ocelli (50–100 m in diameter) of Polyorchis penicillatus is described. The ocellar cup is formed of pigment cells and receptor cells. The pigment cells occur in approximately a 2:1 ratio to the receptor cells. Each pigment cell has a process that may pass through the presumed photosensory region. Pigment cells are connected to adjacent receptor cell processes by septate junctions. The sensory cells are bipolar with the apical part forming the receptor process and the basal part forming an axon 8–15 m long and 1–2 m in diameter. Each receptor cell axon forms a synapse with a single second order neuron but the sensory cells are also connected to the second order neurons postsynaptically. There are also synapses between adjacent second order neurons. The second order neurons lie outside the ocellar cup, next to the tentacular mesogloea. Each second order neuron forms an axon of about 1 m thickness. The axons on each side group together to form an optic nerve having 30–40 axons that travel around the tentacle base on either side and enter the outer nerve ring independently.     

Plant regeneration via somatic embryogenesis in Styrian pumpkin: cytological and biochemical investigations

Somatic embryo formation was induced from cotyledon explants of Styrian pumpkin (Cucurbita pepo L. subsp. pepo var. styriaca Greb.) by using a solid MS medium supplemented with 16.11M NAA and 4.44M BA or 26.85M NAA and 13.32M BA. The callus proliferation was more efficient on medium supplemented with 26.85M NAA and 13.32M BA. In contrast, the embryogenic response was higher on medium with lower concentrations of growth regulators (16.11M NAA and 4.44M BA). The time needed for embryo induction did not depend on medium composition. Embryos in globular stage were transferred to three different maturation media, containing 2.89M GA₃ in combination with 0.54M NAA, 11.42M IAA and growth regulator-free medium. The germination rate was the highest when embryos were cultured on medium with 11.42M IAA. Plantlets grown on this medium achieved maturity suitable for transplantation into soil within 9 to 10weeks. The regenerated plants were successfully transferred into field and developed fertile flowers and set fruits. Biochemical analysis showed significant lower total glutathione levels among in vitro grown plantlets compared to seedlings grown in soil. When the plantlets were transferred into soil, they reached a normal size within a month and the glutathione concentration was comparable to seed-derived plants at the same developmental stage. Transmission electron microscopy was used to investigate possible differences in the ultrastructure of cells from callus cultures, and leaf cells of regenerated and seed-derived plants. Differences in the ultrastructure were found within chloroplasts which contained only single thylakoids, large starch grains and small plastoglobuli in callus cells in comparison to leaf cells, which possessed a well developed thylakoid system, small starch grains and large plastoglobuli.     

Transforming activities of sodium fluoride in cultured Syrian hamster embryo and BALB/3T3 cells

The transforming activity of sodium fluoride was studied in the SHE and the BALBl3T3 cell culture systems. Initiating and promoting activities were then investigated by means of the orthogonal methodology. Sodium fluoride was found to induce morphological transformation of SHE cells seeded on a feeder layer of X-irradiated cells at high concentrations (75–125 g/ ml). When the cells were seeded in the absence of a feeder-layer, the transformation frequencies increased in a dose-dependent manner with the concentrations of sodium fluoride ranging from 0 to the highly toxic concentration of 200 g/ml. In the BALBl3T3 cell system, sodium fluoride was negative in the standard Kakunaga procedure, while through the experiment designed by table L₈ (2⁷) of the orthogonal method, an initiating-like effect and a weak promoting activity were detected within the concentrations ranging from a 25 g/ ml to a 50 g/ ml concentration which is highly toxic for BALBl3T3 cells. From these results, it is suggested that, besides a genetic mode of action, sodium fluoride could possibly act through a non-genotoxic mechanism.Abbreviations CE cloning efficiency - NaF sodium fluoride - SHE Syrian hamster embryo - TF transformation frequency     

Differences in the growth inhibition of cultured K-562 cells by selenium, mercury or cadmium in two tissue culture media (RPMI-1640, Ham's F-10)

Effects of some metals on the growth of cultured human erythroleukemia K-562 cells were investigated when grown in two different types of media based upon RPMI-1640 or Ham's F-10. The study on proliferation, using RPMI-1640 supplemented with sodium selenite, selenomethionine, mercuric chloride, methylmercuric chloride and cadmium nitrate showed no inhibition of growth at concentrations of 2.5, 25, 25, 2.5 and 25 M, while at 75, 250, 50, 5 and 50 M toxicity was apparent. Selenite at 5–50 M and selenomethionine at 50–100 M inhibited the growth. In Ham's F-10 supplemented with the same compounds no inhibition was found at concentrations of 5, 10, 25, 1 and 50 M, while at 50, 100, 50, 5 and 75 M toxic effects were noted. Selenite 10 M and selenomethionine 25-50 M inhibited the proliferation. Measurements of trace element levels in pellets of K-562 cells grown in RPMI-1640 or Ham's F-10 unveiled higher cell contents of cadmium and selenium in cells grown in RPMI-1640, being consistent with higher concentrations of these elements in that medium. Manganese and mercury concentrations were higher in cells grown in Ham's F-10 correlating with a higher medium concentration of these elements. The growth responses and cellular uptake differed between the metals and the selenocompounds and although extrapolating the results to humans is difficult the selenium exposures were in approximately the same order of magnitude as in human exposures. The compounds could be ranked according to decreasing toxicity as: methylmercuric chloride > mercuric chloride, cadmium nitrate, sodium selenite > selenomethionine.     

The spermatozoon of Oikopleura dioica Fol (Larvacea,Tunicata)

Summary The spermatozoon of Oikopleura dioica is about 30 m long, with a spherical head, about 1 m wide, a 3 m long and 1 m wide midpiece, and a 25 m long tail with a tapered end piece. The head contains a nucleus with the chromatin volume limited to about 0.1 m³. A small acrosome is found in an anterior inpocketing, and a flagellar basal body in a posterior inpocketing of the nucleus. The midpiece contains a single mitochondrion with the flagellar axoneme embedded in a groove along its medial surface. The flagellar axoneme has the typical 9 + 2 substructure, and the basal body the typical 9+0 substructure. A second centriole and special anchoring fibres are absent.     

Inward rectifier K channels in renal epithelioid cells (MDCK) activated by serotonin

Summary The present study has been performed to test for the effect of intracellular calcium and of serotonin on the channel activity in patches from subconfluent MDCK-cells. In inside-out patches, inwardly rectifying potassium-selective channels are observed with open probabilities of 0.01±0.01, 0.24±0.03 and 0.39±0.07, at 100 nmol/liter, 1 mol/liter or 10 mol/liter calcium activity, respectively. The single-channel slope conductance is 34±2 pS, if the potential difference across the patch (V ) is zero, and approaches 59±1 pS, ifV is –50 mV, cell negative. In the cell-attached mode, little channel activity is observed prior to application of serotonin (open probability=0.03±0.03). If 1 mol/liter serotonin is added to the bath perfusate, the open probability increases rapidly to a peak value of 0.34±0.04 within 8 sec. In continued presence of the hormone, the open probability declines to approach 0.06±0.02 within 30 sec. At zero potential difference between pipette and reference in the bath (i.e., the potential difference across the patch is equal to the potential difference across the cell membrane), the single-channel conductance is 59±4 pS. In conclusion, inwardly rectifying potassium channels have been identified in the cell membrane of subconfluent MDCK-cells, which are activated to a similar extent by increase of intracellular calcium activity to 1 mol/liter and by extracellular application of 1 mol/liter serotonin.     

Development of an L6 myoblast in vitro model of moniliformin toxicosis

L6 myoblasts were used as an in vitro model to investigate the role of moniliformin and its interaction with monensin in turkey knockdown syndrome and sudden death syndromes in poultry. Cell viability and microscopic and ultrastructural alterations noted in L6 myoblasts cultured in the presence of moniliformin (0.0–0.3 g/l) were compared to those observed in parallel cultures also containing one of the following compounds: selenium (0–0.004 ng/l), thiamine (0–0.3 g/l), or pyruvate (0–0.46 g/l). Marked dilation of the RER, membranous whorls, glycogen deposition, membrane-bound cytoplasmic inclusions and necrosis were observed in myoblasts exposed to 0.03/2-0.30 g moniliformin/l medium. Supplementation of medium with thiamine and pyruvate, or selenium, provided significant protection to cells exposed to 0.0–0.3 g/l or 0.0–0.15 g moniliformin/l, respectively. Dose-dependent differences in protein and ATP production were not detected. Myoblasts grown in medium containing 0–0.15 g moniliformin/l and 7.5–50.0 M A23187, beauvericin or monensin had degrees of cytotoxicity similar to parallel cultures receiving only an ionophore. L6 myoblasts were a useful model of moniliformin toxicosis. The findings of this study suggest cytotoxicity due to moniliformin in L6 myoblasts may be due in part to oxidative damage and altered pyruvate metabolism, and that moniliformin does not predispose myoblasts to ionophore toxicosis. This study supports the results of in vivo investigations in poultry that moniliformin and monensin do not act synergistically to induce knockdown or monensin toxicosis.     

Effects of atrial natriuretic factor,nitroprusside and acetylcholine on cGMP immunostaining in the isolated perfused rat kidney

Summary In the present study the localization of the cGMP production in response to the vasodilators acetylcholine (ACh) and sodium nitroprusside (SNP) and to atrial natriuretic factor (ANF) was studied in the isolated perfused rat kidney using cGMP immunocytochemistry. After ACh (0.3 M) infusion increased cGMP immunoreactivity was found in kidney interlobar and segmental arteries and in glomeruli. SNP (1 M) and ANF (0.01 M) elevated cGMP staining in the same elements of the kidney as ACh. In the glomeruli ACh and SNP stimulated cGMP production in mesangial cells whereas ANF stimulated cGMP production in epithelial cells (podocytes). However, SNP at higher doses (10 M) stimulated cGMP production not only in glomeruli, but also in interstitial cells throughout the cortex. In addition SNP and ANF increased cGMP production in the medulla.     

Coccidia of Brazilian edentates: Eimeria cyclopei n.sp. from the silky anteater,Cyclopes didactylus (Linn.) and Eimeria choloepi n.sp. from the two-toed sloth,Choloepus didactylus (Linn.)

Summary Eimeria cyclopei n.sp. is described from the silky anteater, Cyclopes didactylus, from Pará State, north Brazil. Undifferentiated oocysts, passed in the faeces, complete sporulation in seven days at 26 to 28°C. Oocysts are ellipsoidal to sub-spherical, with a mean size of 28.1 × 23.6 m: the wall is 1.5 to 2.0 m thick, apparently with an outer thin, colourless membrane and two inner, thicker, striated and yellowish layers. There is no micropyle, oocyst residuum or polar body. The mean measurements of sporocysts are 19.0 × 9.0 m, and they are slightly asymmetrical, elongate pear-shape, with a plug-shaped Steida body projecting beyond the end of the sporocyst. Sporozoites are as long as or longer than the sporocysts: The sporocyst residuum is scattered between sporozoites in younger specimens and becomes condensed into rounded mass in older ones. The endogenous stages occur in the epithelial cells of the ileum, on the lumenal side of the host-cell nucleus. Uninucleate meront, microgamont and macrogamont precursors are recognizable morphologically. Mature meronts are 20.0 × 15.7 m some produce 12 to 20 merozoites which are 8.7 × 2.0 m, and others 10 to 26 merozoites which are 11.4 × 2.0 to 15.0 × 3.0 m. Mature microgamonts which are 27.5 × 24.1 m, produce from 150 to 170 microgametes of 7.1 × 1.0 m: microgametes have two flagella of unequal length. Mature macrogamonts are 28.4 × 24.5 m Eimeria choloepi n.sp. is recorded from the two-toed sloth, Choloepus didactylus, from the same area of Brazil. Undifferentiated oocysts, passed in the faeces, complete sporulation in 23 days at 26 to 28°C. Oocysts with a mean size of 23.0 × 20.3 m, have a wall 2.0 to 2.5 m thick which is composed of two thick, yellowish and striated outer layers and a delicate, colourless inner one. There is no micropyle, oocyst residuum or polar granule. Mature sporocysts with a mean size of 11.3 × 7.1 m, are ellipsoidal to egg-shaped and have a poorly developed Steida body. The sporocyst residuum is composed of a small number of large globules: The sporozoites are longer than the sporocyst and strongly recurved. The endogenous stages occur in epithelial cells of the ileum, on the lumenal side of the host-cell nucleus. Dimorphic meronts produce 8 to 18 merozoites which are either 13.0 × 2.0 m or 13.0 × 3.0 m. Microgamonts produce 50 to 80 microgametes of 8.0 × 1.0 m. Mature macrogamonts are 18.3 × 17.9 m. ac]19820212