Ultrastructure of in vivo-produced caryocysts containing the coccidian Caryospora bigenetica (Apicomplexa: Eimeriidae)

A cotton rat was inoculated orally with oocysts of Caryospora bigenetica from the feces of a rattlesnake. Sixteen days later the rat was euthanized, and portions of the scrotum, foot pad and muzzle were processed for histological sections and transmission electron microscopy. Sporozoites within caryocysts had typical coccidian features such as an anterior and posterior refractile body, centrally located nucleus, micronemes, rhoptries, a conoid, a micropore near the anterior refractile body, a posterior pore, amylopectin granules, lipid bodies, a Golgi-like body, a mitochondrion and subpellicular microtubules. The infected host cell was spherical and surrounded by a fibrous wall-like covering, 0.35-1.00 microns thick. This outer covering, when viewed in stained histological sections, was periodic acid-Schiff (PAS)-positive.     

Early Development of Eimeria Papillata (Apicomplexa: Eimeriidae) In the Mouse

ABSTRACT Early development of Eimeria papillata (Apicomplexa) in the mouse was evaluated using Nomarski interference-contrast and brightfield microscopy. Sporozoite-shaped meronts, which were motile and contained a large posterior refractile body and a smaller anterior refractile body, were observed entering and leaving host cells in the jejunum of an experimentally infected mouse at 26 h post inoculation (HPI). However, early developmental stages were not observed in tissue of the duodenum, ileum, cecum and colon. the mean length and width of these meronts (n = 20) were 12.0 μm and 3.7 μm, respectively. Spherical or subspherical meronts containing crescent-shaped merozoites were observed at 36 HPI.     

Early development of Eimeria papillata (Apicomplexa: Eimeriidae) in the mouse

Early development of Eimeria papillata (Apicomplexa) in the mouse was evaluated using Nomarski interference-contrast and brightfield microscopy. Sporozoite-shaped meronts, which were motile and contained a large posterior refractile body and a smaller anterior refractile body, were observed entering and leaving host cells in the jejunum of an experimentally infected mouse at 26 h post inoculation (HPI). However, early developmental stages were not observed in tissue of the duodenum, ileum, cecum and colon. The mean length and width of these meronts (n = 20) were 12.0 microns and 3.7 microns, respectively. Spherical or subspherical meronts containing crescent-shaped merozoites were observed at 36 HPI.     

Description of the oocysts of Eimeria paludosa (Apicomplexa: Eimeriidae) from Fulica americana (Aves: Gruiformes), with comments on synonyms of eimerian species from related birds

Between November and December 1988, fecal and intestinal contents were collected from 25 northern American coots, Fulica americana americana, in Arkansas and Texas, and examined for coccidial parasites. Seventeen (68%) of the coots were infected with Eimeria paludosa, herein described; for the first time, photomicrographs of the species are presented. Sporulated oocysts are ovoid, 16.5 x 12.6 (15-23 x 11-14) microns, with a lightly to heavily pitted single-layered wall; an oocyst residuum is absent, but a prominent micropyle is present. A large, or several smaller, polar granule(s) is present, usually located beneath the micropyle. Sporocysts are elongate-ovoid, 10.8 x 6.2 (10-12 x 5-7) microns, with Stieda and substieda bodies. A sporocyst residuum is present, normally composed of very fine faint granules scattered among the sporozoites or, rarely, as a spherical mass. Sporozoites are elongate, 8.7 x 2.7 (7-11 x 2-3) microns, in situ. Each sporozoite contains a spherical-ellipsoid posterior refractile body and occasionally a spherical anterior refractile body. A nucleus is located immediately anterior to the posterior refractile body. The occurrence of E. paludosa in F. a. americana is a new host and geographic record for the parasite. In addition, several of the previously described eimerian species from gruiform birds are proposed to be synonyms of E. paludosa.     

Three New Species of Eimeria (Apicomplexa: Eimeriidae) from Nerodia rhombifem (Serpentes: Colubridae) from Texas1

Three new species of Eimeria (Apicomplexa: Eimeriidae) are described from the intestinal contents of Nerodia rhombifera (Serpentes: Colubridae) from Texas. Oocysts of Eimeria infirmus are irregular in shape, 11.6 (8.8–14.4) μm in diameter, with a smooth, thin wall that ruptures easily, releasing free sporocysts. A small polar granule is usually present, but a micropyle and oocyst residuum are absent. Sporocysts are bean-shaped with one side flattened slightly, 9.1 times 5.0 (7.2–10.4 times 4.4–5.8) μm, with what may be a Stieda body consisting of a slight thickening of one end of the sporocyst. Each sporocyst contains a spherical or ellipsoid residuum and sporozoites, each with a single, posterior refractile body. Oocysts of Eimeria rhombifera are spherical or subspherical, 13.1 times 12.6 (12.0–14.4 times 11.2–14.4) μm, with a smooth, frail wall. A polar granule is present, but a micropyle and oocyst residuum are absent. Sporocysts are ovoid, 8.8 times 5.5 (8.0–9.6 times 5.0–6.0) μm, each with a Stieda body. Each sporocyst contains a spherical or subspherical residuum and sporozoites, each with a single posterior refractile body. Oocysts of Eimeria tenuis are ellipsoidal in shape, 17.2 times 10.8 (15.2–20.8 times 9.6–12.0) μm, with a smooth, thin wall. A polar granule and oocyst residuum are present, but a micropyle is absent. Sporocysts are elongate, 13.2 times 4.9(11.2–15.2 times 4.4–5.6) μm, each with a Stieda body consisting of a thickening of the sporocyst wall. Each sporocyst contains a spherical or subspherical residuum and sporozoites with anterior and posterior refractile bodies.     

Three‐dimensional organization of flagellar basal apparatus in Ectocarpus gametes

The flagellar basal apparatus of the brown alga Ectocarpus siliculosus was re‐investigated in details using transmission electron microscopy and electron tomography. As a result, three‐dimensional structures with spatial arrangement of bands and microtubular flagellar rootlets were observed. Fibrous structures linking the anterior flagellar basal body to the major anterior rootlet (R3) or the bypassing rootlet was newly discovered in this study. A direct attachment from the minor anterior rootlet (R4) to the anterior and posterior basal bodies was also discovered, as were attachments from the minor posterior rootlet (R1) to the deltoid striated band and from the major posterior rootlet (R2) to the posterior fibrous band. The microtubular flagellar rootlets were connected to the bands and to the anterior or posterior basal body. These bands may have a role in maintaining the spatial arrangement of the anterior and posterior flagellar basal bodies and the microtubular flagellar rootlets. A numbering system of the basal body triplets was established by tracing axonemal doublets in the serial sections. From these observations, the precise position of two flagellar basal bodies, bands, and flagellar rootlets was determined.     

A new species of Eimeria (Apicomplexa: Eimeriidae) from the eastern pipistrelle, Perimyotis subflavus (Chiroptera: Vespertilionidae), in Arkansas

During November 2009 and March 2010, 20 adult eastern pipistrelles, Perimyotis (= Pipistrellus) subflavus, were collected from Polk County, Arkansas, and their feces were examined for coccidian parasites. Two (10%) of the bats were found to be passing oocysts of an undescribed species of Eimeria. Oocysts of Eimeria heidti n. sp. were ovoidal to ellipsoidal, 26.1 × 20.5 μm (23-31 × 18-23 μm), with a bilayered wall, externally rough, internally smooth, and with a shape index of 1.3. Micropyle and oocyst residuum were absent, but a subspherical polar granule was often present. Sporocysts were ovoidal, 13.0 × 8.8 μm (11-15 × 7-13 μm), the shape index was 1.6, a Stieda body was present and sub-Stieda and para-Stieda bodies were absent. A sporocyst residuum consisting of multiple globules dispersed along the perimeter of the sporocyst and between the sporozoites were present, sporozoites were elongate, with a subspherical anterior refractile body and elongate posterior refractile body; a nucleus not discernible. This is the second coccidian reported from this host and the fourth instance of a coccidian species reported from an Arkansas bat.     

Coccidian Parasites (Apicomplexa: Eimeriidae) of Nerodia spp. (Serpentes: Colubridae), with a Description of a New Species of Eimeria

Eimeria conanli n. sp. (Apicomplexa: Eimeriidae) is described from intestinal contents and feces of Nerodia erythrogaster transversa and N harteri harteri from northcentral Texas. Oocysts of the new species are ellipsoid in shape. 17.9 × 13.0(15–21 × 12–15) μm, with a smooth, thin, single-layered wall; shape index 1.4 (1.2–1.5). One to several (usually 2) polar granule(s) and an oocyst residuum are present, but a micropyie is absent. Sporocysts are elongate, 12.9 × 5.2 (13–15 × 5–6) -m, apparently without a true Stieda body structure. Each sporoeyst contains an ellipsoid residuum, 3.9 × 3.2 (3–6 × 2–4) μm, and elongate sporozoites, 11.4 × 2.5 (10–14 × 2–3) μm in situ, each with a spherical or subspherical anterior refractile body and spherical to ellipsoid posterior refractile body. In addition to the new species, oocysts of 4 previously described eimerians from colubrid snakes were found in these hosts.     

Comparative analysis of the circulatory system in Amphipoda (Malacostraca, Crustacea)

We present data on the haemolymph vascular system (HVS) in four representatives of the major amphipod lineages Gammaridea, Hyperiidea and Caprellidea based on corrosion casting and three‐dimensional reconstructions of histological semi‐thin sections. In all these species the HVS comprises a dorsal pulsatile heart, which is continued in the body axis by the anterior and posterior aortae. The heart is equipped with three pairs of incurrent ostia. The number of cardiac arteries that lead off the heart varies among species: in the studied Gammaridea four pairs occur, in Hyperia galba only the three posterior pairs of cardiac arteries occur, while in Caprella mutica cardiac arteries are absent. In all the studied species the posterior aorta leads as a simple tube into the pleon attached to the dorsal diaphragm. The anterior aorta runs from its origin in the anterior part of the second thoracic segment into the cephalothorax. Both pairs of antennae have an arterial supply off the anterior aorta. An overview of previously studied species including our present findings shows the amphipod HVS to be relatively uniform and the gammarid form is discussed as being closest to the ground pattern of Amphipoda.     

Functional morphology of the glandula prostatica,ejaculatory valve,and ductus ejaculatorius of the silkworm Bombyx mori

The penis of the silkmoth, Bombyx mori, consists of two parts covered with cuticle, the corpus penis and crus penis, and a third part, the radix penis, without a cuticle but surrounded by a thick sphincter. The radix penis is divisible into anterior and posterior parts. The ductus (d.) ejaculatorius passing through the penis has no secretory cells. In the anterior radix penis, the wall of the d. ejaculatorius is thin and without folds; in the posterior section, it is thick, with folds in its lumen. The glandula (g.) prostatica is divisible into anterior and posterior parts according to differences in the histological and morphological characteristics of the cells and their secretions, which contain many heterogeneous substances. In the anterior g. prostatica, secretions accumulate separately in the anterior and posterior sections before ejaculation. Unlike the posterior region, the anterior region displays a large mass(es) at the periphery of the lumen along the secretory cell layer. Judging from staining properties, the pearly body and the first layer of the spermatophore wall, which, after copulation, form in the female bursa copulatrix, seem to be derived from the secretions of the anterior and posterior regions of the g. prostatica, respectively. The secretion of the posterior g. prostatica contains initiatorin, which acts as a sperm-activating factor in the inner and outer matrices of the spermatophore. An ejaculatory valve is found between the radix penis and the g. prostatica. The opening of this valve is regulated by the surrounding sphincter, thus impeding the back-flow of secretions and seminal fluid in the radix penis and resulting in their transport outwards during ejaculation. The musculature of the d. ejaculatorius and the corpus penis promotes further transport of these secretions into the female bursa copulatrix.     

Blood supply of the rat hypothalamus. VI. Posterior region of the hypothalamus (nucleus hypothalamicus posterior, nuclei praemammillares, nucleus supramammilaris, mammilary body).

It was shown by the double ink-filling technique that the arteries of the rat premammillary region and mammillary body arise from the a. communicans posterior while these areas are drained by the anterior interpeduncular vein. Disregarding some minor overlaps and anastomoses, the blood supplies of the two territories are independent of each other and from the neighbouring areas of the hypothalamus, diencephalon and mesencephalon. Arteries of the premammillary region arise from the premammillary artery, except for some branches of the posterior tuberal and interpeduncular arteries. The mammillary body is supplied by three mammillary arteries (anterior, posterior and lateral). The premammillary region drains into the anterior and posterior premammillary veins. Venous blood of the mammillary body is collected by the anterior and posterior mammillary veins which end in the anterior interpeduncular vein. The circulation of individual premammillary and mammillary nuclei is described in detail.     

Eimeria ochrogasteri n. sp. from the Prairie Vole Microtus ochrogaster*

SYNOPSIS. Eimeria ochrogasteri n. sp. (Coccidia, Eimeriidae) from a prairie vole Microtus ochrogaster (Rodentia, Cricetidae) is described. This is the first recorded coccidium in prairie voles. Sporulated oocysts spherical to ellipsoidal, mean 24.0 by 20.5 μ. Oocyst wall double, outer layer thick, yellow-brown, deeply pitted, inner layer clear. Oocyst residuum varies from many small globules to a coalesced group of large and/or small globules. Polar granule present. Micropyle absent. Sporocysts ovoid with “capped” Stieda body, mean 12.3 by 8.2 μ. Sporocyst residuum present. Sporozoites average 14.9 by 2.9 μ with spherical anterior and oblong posterior refractile globules. This species was found in 1 of 71 voles from Weld county, Colorado.     

Ultrastructural aspects of the 'statocyst' of Xenoturbella (Deuterostomia) cast doubt on its function as a georeceptor

The "statocyst" in the enigmatic worm Xenoturbella is a structure containing motile flagellated cells. It is situated inside the subepidermal membrane complex (between epidermis and muscular layers) in the anterior end of the body. The motile cells contain a lipophilic refractile body ("statolith"), and a series of vesicles from small dense core vesicles presumably formed from the refractile body to large vesicles with dense aggregates of filamentous tubules that become exocytized through secretion. It is unlikely that the statocyst is a georeceptor (true statocyst); maybe it has an endocrine function.     

<Emphasis Type="Italic">Eimeria maricopensis</Emphasis> n. sp. (Apicomplexa: Eimeriidae) from the Arizona cotton rat <Emphasis Type="Italic">Sigmodon arizonae</Emphasis> Mearns (Rodentia: Cricetidae) in central Arizona,USA

Eimeria maricopensis n. sp. (Apicomplexa: Eimeriidae) is described from 2 of 15 (13%) Arizona cotton rats Sigmodon arizonae Mearns in Arizona, USA. Sporulated oöcysts of this new species are ovoidal to ellipsoidal, 20–28 × 16–22 (24.9 × 19.2) µm, with a smooth, bi-layered wall; both micropyle and oöcyst residuum are absent, but fragmented polar granule material is present. Sporocysts are ellipsoidal, 11–14 × 6–8 (12.9 × 7.0) µm, with a Stieda body, sub-Stieda body, and sporocyst residuum; sporozoites are elongate with a spheroidal anterior refractile body and a subspheroidal posterior refractile body. In addition, sporulated oöcysts of Eimeria sigmodontis Barnard, Ernst & Dixon, 1974, Eimeria tuskegeensis Barnard, Ernst & Dixon, 1974 and Eimeria webbae Barnard, Ernst & Dixon, 1974 are described from S. arizonae. This is the first report on the coccidia of S. arizonae.     

Light and electron microscopy on the sporulation of the oocysts of Eimeria brunetti. II. Development into the sporocyst and formation of the sporozoite

The later stages of sporulation in oocysts of Eimeria brunetti were examined in samples which had been allowed to sporulate at 27 degrees C for 24, 36 and 48 hours. It was observed that the sporoblasts became ellipsoidal and the nucleus underwent the final division. A nucleus with associated Golgi bodies was not observed at either end of the organism. The cytoplasm was limited by two unit membranes and contained rough endoplasmic reticulum, dense bodies, electron translucent vacuoles and mitochondria. The first evidence of sporozoite formation was the appearance of a dense plaque at either end of the organism. This appeared in the vicinity of the nuclei, and adjacent to the limiting membrane of the soroblast. At this stage the sporocyst wall was still unformed. Then the two sporozoites were formed from opposite ends of the organism by growth of the dense plaques and invaginations of the plasmalemma which thus formed the pellicles of the developing sporozoites. A conoid and subpellicular microtubules were observed at this stage as development continued, a number of vacuoles were found between the nucleus and the conoid. These vacuoles constituted the precursors of the rhoptries and micronemes. At the same stage a large dense body had appeared within the forming sporozoite. As the sporozoite developed, this body, anterior refractile body, is followed by the nucleus and another dense body which formed the posterior refractile body. During this period, the thin sporocyst wall was formed and Stieda and sub-Stieda bodies were now present at one end of the sporocyst. Each mature sporocyst contained two sporozoites.     

Immunohistochemical localization of S-100-containing cells in non-nervous structures of the human eye

The present study reports on the immunohistochemical distribution of S-100 antigen in non-nervous cell types within the human eye at light microscopy. In the cornea the antigen was confined to endothelial cells covering its posterior surface; the lens exhibited immunoreactivity restricted to the epithelial cells located beneath the anterior capsule. In the iris and ciliary body, S-100 was detected in stromal cells and epithelial cells of the pigmented inner layer in the former and inner epithelial cells bounding the posterior chamber in the latter.     

KATABLEPHARIS OVALIS,A COLORLESS FLAGELLATE WITH INTERESTING CYTOLOGICAL CHARACTERISTICS1

Katablepharis ovalis Skuja, isolated from an impoundment in Colorado, has a cell covering composed of two layers over the cell body and flagella. The outer component of the cell covering contains 25-nm-diameter hexagonal scales arranged in rows. The inner component of the cell covering is composed of a layer of interwoven microfibrils. The inner component of the cell covering is joined to the plasma membrane by one or more attachment strips that always occur outside, and along, one of the microtubular groups of the outer array. The attachment strips resemble hemidesmosomes and are composed of rows of electron-dense material, 12 nm apart, that protrude through the plasma membrane into the extracellular space, to attach to the inner wall. The two flagella are inserted subapically into a raised area of the cell. The flagella do not have any fibrillar or tubular hairs and are covered only by the two-layered cell covering. The cell has an inner and outer array of microtubules, both of which are spindle-shaped, arising at the anterior end of the cell and continuing into the posterior end of the cell. A single large Golgi apparatus occurs in the anterior cytoplasm. The nucleus is in the center of the cell. Two rows of large ejectisomes occur posterior to the area of flagellar attachment. Smaller ejectisomes occur under the plasma membrane in the posterior and medial areas of the cell. Each ejectisome is composed of a single body containing a spirally wound, tapered ribbon. On discharge, the ejectisome ribbon rolls inward, creating a tubular structure. The possible relationship between Katablepharis, the green algae, and the cryptophytes is discussed.     

Description of the oöcysts of Eimeria septemvittata n. sp. (Apicomplexa: Eimeriidae) from queen snakes,Regina septemvittata (Serpentes: Colubridae), in Arkansas

Coccidian oöcysts recovered from the feces of queen snakes, Regina septemvittata, from Arkansas, USA, were found to represent a previously unreported eimerian. Oöcysts of Eimeria septemvittata n. sp. are spherical or subspherical, 14.6×14.0 (12–16×12–15) μm, with a thin, bi-layered wall; the shape-index (length/width) is 1.04 (1.00–1.17). The micropyle and oöcyst residuum are absent but a large polar granule is present. The sporocysts are ovoidal, 11.3×5.6 (9.5–13.5×5–6) μm and possess a Stieda body; the shape-index is 2.02 (1.81–2.50). Each sporozoite contains a large, centrally located refractile body and a generally smaller, posterior refractile body.