Sarcocystis rommeli,n. sp. (Apicomplexa: Sarcocystidae) from Cattle (Bos taurus) and its Differentiation from Sarcocystis hominis

Cattle (Bos taurus) are intermediate hosts for three named species of Sarcocystis, S. cruzi, S. hirsuta, and S. hominis. Recently, a fourth species was identified and named S. sinensis. However, S. sinensis originally named a species of Sarcocystis in water buffalo (Bubalus bubalis) in China. Based on unverifiable evidence, it was suggested that the same parasite infects cattle. In addition, S. sinensis was recently declared as nomen nudum because its naming violated the rules of International Code of Zoological Nomenclature. Thus, the fourth species using cattle as an intermediate host does not have a valid name. Here, we propose a new name, Sarcocystis rommeli for the S. sinensis‐like parasite from cattle in Argentina, and differentiate it ultrastructurally from S. hominis sarcocysts from experimentally infected cattle. Sarcocystis rommeli sarcocysts were microscopic with a 5‐μm‐thick wall with slender villar protrusions (Vp); the Vp were up to 5 μm long, up to 0.5 μm wide, and of uneven thickness, often bent at an angle. The ground substance layer (Gs) was up to 0.8 μm thick and smooth. Vesicular structures were seen at the base of the Vp. The bradyzoites were 10–12 μm long. Sarcocystis hominis sarcocysts had Vp that were often upright, up to 7.5 μm long, and up to 1.8 μm wide; the Gs was up to 2 μm thick and without vesicles. Its sarcocyst wall was up to 5.6 μm thick, the vp were bent at an angle, up to 5.8 μm long, the Gs was up to 2 μm thick, but without vesicles seen in S. rommeli. Beef containing sarcocysts of S. rommeli was not orally infectious for two human volunteers and a red fox (Vulpes vulpes). The Sarcocystis described here is molecularly different from S. cruzi, S. hirsuta, and S. hominis based on 18S rRNA and cox1 gene sequences.     

黄牛、水牛体内人肉孢子虫18S rRNA基因研究及虫种鉴定

本文对自然感染的水牛源的人肉孢子虫以及黄牛源人孢子虫ＤＮＡ的１８Ｓ ｒＲＮＡ基因的ＰＣＲ扩增产物进行了测序。对年获的８６３ｂｐ的１８Ｓ ｒＲＮＡ基因分析比较表明,二者有较高的同源性,因此认为二者可能同是一种肉孢子虫－－人肉孢子虫（Ｓａｒｃｏｃｙｓｔｉｓ ｈｏｍｉｎｉｓ Ｒａｉｌｌｉｅｔ ａｎｄ Ｌｕｃｅｔ,１８９１）。由此推断,不仅黄牛可作为人肉孢子虫的中间宿主,水牛也可作为人肉孢子虫的中间宿主。     

Fine Structure of Sarcocystis cruzi Schizonts

SYNOPSIS Schizogony of Sarcocystis cruzi Hasselmann (syn. S. fusiformis Railliet) takes place in vascular endothelial cells 26 to 33 days after cattle ingest sporocysts from dogs. Kidney cortex from a heavily infected, dexamethasone-treated bovine was fixed for electron microscopy to determine the method of schizogonie development. Schizogony takes place by endopolygeny characterized by marked enlargement of the parasite nucleus, formation of nuclear lobes, presence of numerous spindles with adjacent pairs of centrioles along the nucleus, and simultaneous formation of daughter merozoites in the cytoplasm adjacent to the spindle poles. Endopolygeny in S. cruzi differs from that in other Sporozoa in that merozoite anlagen are seen in the cytoplasm before any nuclei divide. The resultant merozoites continue development and, when mature, resemble other sporozoan zoites. Upon release from the host cell into capillaries, they travel to muscle tissue to continue the life cycle by forming sarcocysts.     

Life Cycle of Cystoisospora felis (Coccidia: Apicomplexa) in Cats and Mice

Cystoisospora felis is a ubiquitous apicomplexan protozoon of cats. The endogenous development of C. felis was studied in cats after feeding them infected mice. For this, five newborn cats were killed at 24, 48, 72, 96, and 120 h after having been fed mesenteric lymph nodes and spleens of mice that were inoculated with C. felis sporulated sporocysts. Asexual and sexual development occurred in enterocytes throughout the villi of the small intestine. The number of asexual generations was not determined with certainty, but there were different sized merozoites. At 24 h, merogony was seen only in the duodenum and the jejunum. Beginning at 48 h, the entire small intestine was parasitized. At 24 h, meronts contained 1–4 zoites, and at 48 h up to 12 zoites. Beginning with 72 h, the ileum was more heavily parasitized than the jejunum. At 96 and 120 h, meronts contained many zoites in various stages of development; some divided by endodyogeny. The multiplication was asynchronous, thus both immature multinucleated meronts and mature merozoites were seen in the same parasitophorous vacuole. Gametogony occurred between 96 and 120 h, and oocysts were present at 120 h. For the study of the development of C. felis in murine tissues, mice were killed from day 1 to 720 d after having been fed 10⁵ sporocysts, and their tissues were examined for the parasites microscopically, and by bioassay in cats. The following conclusions were drawn. (1) Cystoisospora felis most frequently invaded the mesenteric lymph nodes of mice and remained there for at least 23 mo. (2) It also invaded the spleen, liver, brain, lung, and skeletal muscle of mice, but division was not seen based on microscopical examination. (3) This species could not be passed from mouse to mouse.     

Fine structure of the mouthparts of Diostrombus politus and Proutista moesta (Hemiptera: Derbidae)

Insect mouthparts are important sensory and feeding structures, morphological studies of this organ can provide additional data for phylogenetic studies. The planthopper superfamily Fulgoroidea is among the dominant groups of phytophagous insects, however, the mouthparts ultrastructure of this superfamily remains unsatisfactorily studied. This study investigates the ultrastructure of the mouthparts of two species in the family Derbidae (Hemiptera: Fulgoroidea), Diostrombus politus Uhler and Proutista moesta (Westwood), using a scanning electron microscope. The results show that these two derbids are of a typical piercing-sucking type found in Hemiptera. They consist of a cone-shaped labrum, a three-segmented labium and a stylet fascicle with two interlocked maxillary stylets incompletely wrapped by two mandibular stylets. The arrangement of the sensilla on the labial tip differ slightly between the two derbid species, and the subapical labial sensilla are likely different among genera in the family Derbidae.     

Morphology and ultrastructure of definitive males of Arcticotantulus pertzovi and Microdajus tchesunovi (Crustacea: Tantulocarida)

Free-swimming definitive males of two species of Tantulocarida (Crustacea), Arcticotantulus pertzovi (Basipodellidae) and Microdajus tchesunovi (Microdajidae), were reared for the first time. Their morphology and ultrastructure were studied using scanning electron and light microscopy. A detailed analysis of the morphological characters of all currently described species revealed several features typical for most known male tantulocaridans, such as the presence of eight aesthetascs, seven pairs of multifid sensilla on the carapace, paired brush setae on the protopods of the thoracopods, and three furcal setae. The monophyly of the families Microdajidae and Doryphallophoridae is corroborated, while the families Deoterthridae and Basipodellidae are more likely paraphyletic.     

Phylogenetic utility and comparative morphology of the composite scale brushes in male phycitine moths (Lepidoptera, Pyralidae)

Male pyralid moths in the subfamily of Phycitinae are known to possess composite scale brush structures associated with the 8th abdominal sternite, but the histology and the structural morphology of these organs have not been adequately explored. As such, the phylogenetic utility of these structures is unknown. We examine the pre-genitalic abdominal histology of male Dioryctria reniculelloides (Pyralidae: Phycitinae) associated with the composite scale brushes, as well as structural morphology within the genus Dioryctria and two closely related genera. The composite scale brushes are composed of fused scales. The musculature associated with the base of sternum 8 shows considerable modification compared to previously described Lepidoptera. Complex glandular tissue was also found associated with the scale brush structures, suggesting secretory function. Phylogenetic utility of ultrastructure and gross morphology was examined for major Dioryctria species groups. Many characters were homoplasious, but several supported the monophyly of the genus, as well as some internal relationships. In conclusion, the combination of ultrastructural, gross morphological and histological characters can be a rich source of information for elucidating a range of evolutionary relationships within the subfamily.     

Divergence between the Anoas of Sulawesi and the Asiatic Water buffaloes, inferred from their complete amino acid sequences of hemoglobin ß chains

Four complete amino acid sequences of hemoglobin β chains were determined for the swamp and the river types of the Asiatic water buffalo (Bubalus bubalis) and two species of the subgenus Anoa in Bubalus; B. (A.) depressicornis (H. Smith, 1827), the lowland anoa, and B. (A.) quarlesi (Ouwens, 1910), the mountain anoa. The two types of the bubalis were identical in the 145 amino acid residues of the β chains and, compared to this sequence, the two residues were substituted in the depressicornis (β49Thr → Ser and 134Ala → Thr) and the five were in the quarlesi (β53Val → Ile, 74Met → Ile, 111Val → Ile, 115Arg → His and 134Ala → Thr). While both Anoa species diverged from the bubalis by the β134Ala → Thr, they differed from each other by the five substitutions. The Anoa species are endemic to Sulawesi of Indonesia. Their speciation and the present coexistence were discussed with reference to probable immigrations of two ancestral Anoa species to Sulawesi at so long interval that had caused a reproductive isolation between the two wild animals. The earlier immigrants were postulated to be ancestral to the quarlesi and the later ones to the depressicornis.     

Ultrastructural studies of Sarcocystis cruzi (Hasselmann, 1926) Wenyon, 1926 infection in cattle (Bos taurus): Philippine cases

This paper documents the first report of Sarcocysti s cruzi infection in domesticated cattle (Bos taurus) in the Philippines. Fusiform-shaped microscopic sarcocysts (183-578 microns long and 20-98 microns wide) with distinct septae were found in the skeletal, striated and heart muscle. The sarcocyst wall or parasitophorous vacuolar membrane, 1.37-2.75 microns thick consisted of closely-packed villar protrusions 80-400 nm in dm. Middle and distal segments of VP were bent approximately 90 degrees parallel to the cyst wall surface. The villar core lacked microtubules, and at some points, the distal ends of the VP collectively formed conical tufts. Primary cyst wall had numerous 70-100 nm bubble-like undulations, and the ground substance was 0.25-0.5 micron in thickness. The ultrastructure of S. cruzi cyst wall typifies the Type 7 sarcocyst wall, and bears close similarities with the Philippine and the Vietnam strain of bubaline Sarcocystis levinei.     

A comparative study of competitive ability between two cactophilic species in their natural hosts

Abstract Competition is a major aspect of the ecology of insect communities exploiting ephemeral and fragmented resources. We analysed the effect of intraspecific (single species culture) and interspecific (mixed species culture) competition on larval viability, developmental time and wing length in the cactophilic Drosophila buzzatii and Drosophila koepferae (Diptera: Drosophilidae) reared in cultured media prepared with fermenting tissues of three common natural cactus hosts in nature at different densities. Our results show that all traits measured were affected by both intra‐ and interspecifc competition, although the effect of competition depended on the Drosophila species and the rearing cactus. In fact, flies tended to have a lower viability, shorter wing size and longer developmental time as a function of increasing density in single species culture in both D. buzzatii and D. koepferae (intraespecific competition). Besides, the performance of both species was seriously affected (shorter body size, slower developmental times, lower viability) by the presence of heterospecific competitors except in the case of D. koepferae reared in its primary host plant, Trichocereus terschekii. We also show that D. koepferae successfully utilized Opuntia quimilo, which is absent in most parts of its distribution range. We discuss the roles of intra‐ and interspecific competition as determinants of the relative abundance of these two species in the arid zones of Southern South America.     

Sarcocystis neurona infections in sea otter (Enhydra lutris): evidence for natural infections with sarcocysts and transmission of infection to opossums (Didelphis virginiana).

Although Sarcocystis neurona has been identified in an array of terrestrial vertebrates, recent recognition of its capacity to infect marine mammals was unexpected. Here, sarcocysts from 2 naturally infected sea otters (Enhydra lutris) were characterized biologically, ultrastructurally, and genetically. DNA was extracted from frozen muscle of the first of these sea otters and was characterized as S. neurona by polymerase chain reation (PCR) amplification followed by restriction fragment length polymorphism analysis and sequencing. Sarcocysts from sea otter no. 1 were up to 350 microm long, and the villar protrusions on the sarcocyst wall were up to 1.3 microm long and up to 0.25 microm wide. The villar protrusions were tapered towards the villar tip. Ultrastructurally, sarcocysts were similar to S. neurona sarcocysts from the muscles of cats experimentally infected with S. neurona sporocysts. Skeletal muscles from a second sea otter failed to support PCR amplification of markers considered diagnostic for S. neurona but did induce the shedding of sporocysts when fed to a laboratory-raised opossum (Didelphis virginiana). Such sporocysts were subsequently fed to knockout mice for the interferon-gamma gene, resulting in infections with an agent identified as S. neurona on the basis of immunohistochemistry, serum antibodies, and diagnostic sequence detection. Thus, sea otters exposed to S. neurona may support the development of mature sarcocysts that are infectious to competent definitive hosts.     

Two new species of the genus Stenamoeba (Discosea,Longamoebia): Cytoplasmic MTOC is present in one more amoebae lineage

Two new species of the recently described genus Stenamoeba, named S. berchidia and S. sardiniensis were isolated from a single soil sample on Sardinia, Italy. Both share morphological features characteristic to Stenamoeba and form in phylogenetic analyses together with other Stenamoeba spp. a highly supported clade within the family Thecamoebidae. The ultrastructural investigation of Stenamoeba sardiniensis revealed the presence of cytoplasmic microtubule-organizing centers (MTOCs), located close to one of several dictyosomes found inside the cell. This is the first report of cytoplasmic MTOCs among Thecamoebidae. The presence of MTOCs is now shown in five of nine orders comprising the class Discosea and potentially could be a phylogenetic marker in this group. We re-isolated Stenamoeba limacina from German soils. This strain shows a similar morphology and an almost complete SSU rDNA sequence identity with the type strain of S. limacina originating from gills of fishes, collected in Czech Republic.     

Experimental infections with African trypanosomes: IV. Immunization of cattle with gamma-irradiated Trypanosoma rhodesiense

Cattle immunized with gamma-irradiated Trypanosoma rhodesiense were protected against a challenge inoculation of unirradiated trypanosomes given 1 wk later. These animals were still resistant when rechallenged after 8 mo and some residual immunity persisted for 14 mo after immunization. Animals which had undergone self-cure after infection were resistant when challenged 14 mo later. No resistance was observed in animals challenged with a heterologous strain of T. rhodesiense. The infections observed in unprotected bovines were of a mild nature. Leukopenia and fever were common early in the course of infection, but no anemia was evident at any time.     

Comparative ultrastructural study of the cuticle and spermatozoa in Propappus volki Michaelsen, 1916 (Annelida: Clitellata)

The ultrastructure of the cuticle and mature spermatozoa of the oligochaete Propappus volki Michaelsen, 1916 is described with the aim of providing additional data for clarifying the systematic position of the taxon. P. volki is a fresh-water species living in streams, and is easily recognized by its proboscis on the pre-segmental prostomium and, in mature specimens, by a clitellum covering the segments XII–XIV. The cuticle is composed of a proximal fibre zone and a distal layered epicuticle covered with membrane-bound epicuticular projections. The fibre zone consists of collagenous fibres in a matrix, arranged in either densely packed parallel layers with the fibres oriented in the same direction, or with more loosely distributed fibres, although with the same main orientation. The epicuticular projections are pyramidal with the base leaning on the outer surface of the epicuticle. The cuticle covering the proboscis differs in morphology from that of the rest of the worm; the fibre zone is composed of thin and short fibrils running in all directions, and the epicuticular projections are longer and more narrow than the projections in other regions of the worm.

The spermatozoa are filiform cells formed, in sequence, by an acrosome, an elongated nucleus, a long midpiece, and a flagellum. The acrosomal tube is short and straight with a completely external acrosomal vesicle. Following the acrosome is a apically corkscrew-shaped and basally straight nucleus. The midpiece is twisted and formed by five mitochondria. The flagellum shows a prominent central sheath arrangement.

A comparison with ultrastructurally described cuticles and spermatozoa from other clitellate species reveals most similarities with enchytraeids.     

Phylogenetic position and morphology of Raphidiophrys elongata sp. nov. (Haptista: Centroplasthelida) with notes on cyst wall structure and evolution

The majority of centrohelids bear external coverings consisting of organic spicules or siliceous scales. Cyst coverings are usually reinforced with additional layers of modified scales. The cyst wall of Raphidiophrys heterophryoidea has an unusual and complex structure. It consists of three different types of scales and includes the mosaic scale layer not known in other centrohelids. During excystment, the cyst wall fragments along the sutures of the mosaic layer. For other Raphidiophrys species, cyst coverings are not studied. The present paper describes a new Raphidiophrys species, R. elongata, belonging to the NC7 environmental clade. Trophozoites bore thin plate scales with reduced upper plate. Under starvation, cysts emerged in clonal cultures. Cyst coverings of R. elongata and R. heterophryoidea were studied in comparison with the use of FIB-SEM. Cyst wall of R. elongata was significantly thinner than in R. heterophryoidea and was formed with 3–5 layers of uniform overlapping scales. No mosaic scale layer was present. During excystment, trophozoite exited cyst shell through random fissure. Possible evolutionary events and driving forces behind the complication of cyst wall within Raphidiophrys were discussed.     

Ultrastructural cytochemistry of the sex pheromone glands of Lutzomyia cruzi male sand flies (Diptera: Psychodidae: Phlebotominae)

The sex pheromone glands of Lutzomyia cruzi male sand flies (Diptera: Psychodidae) were analyzed by cytochemical techniques. In adult males, the epithelium at the fourth abdominal tergite is modified into a glandular epithelium, with large columnar gland cells located side by side. The gland cell cytoplasm contains a large number of mitochondria and peroxisomes, the latter with positive (electron-dense) reaction for catalase, a typical peroxisomal enzyme marker. The gland cell cytoplasm also contains a central vacuolated area, with a large number of electron-lucent vacuoles, not limited by a unit membrane. In well-preserved preparations such vacuoles present a homogenous and slightly electron-dense content, typical of lipid droplets. Indeed, incubation of the tergites with imidazole-buffered osmium tetroxide (to detect lipids) resulted in positive reaction in these vacuoles, as well as in between the microvilli of the gland cells. Use of the osmium–potassium iodide (Os–KI) technique allowed to demonstrate the presence of several endoplasmic reticulum (ER) profiles, as expected in secretory cells. Our data suggest that ER, lipid droplets and peroxisomes are involved in the sand fly pheromone biosynthesis.     

The coxal glands of geophilomorpha (chilopoda): Organs of osmoregulation

Summary The organs terminating at the coxal pores of the tug-legs of Geophilomorpha are not repugnatorial glands, but possess typical transport epithelia with deep apical and basal infoldings of the cell membranes, between which numerous large mitochondria are located. Many transport vesicles are found in the basal region but fewer in the apical cytoplasm. The apex is characterized by bundles of longitudinally oriented microtubules, sparse endoplasmic reticulum and free ribosomes. Single neurosecretory axons with synaptoid areas are scattered among the cells. It is suggested that the coxal organs have a diuretic function in moist habitats and an antidiuretic effect in arid environments. The switch-over is evidently controlled by a neuroendocrine mechanism.