Light and electron microscopic studies of<Emphasis Type="Italic"> Myxobolus stomum</Emphasis> n. sp. (Myxosporea: Myxobolidae) infecting the blackspotted grunt<Emphasis Type="Italic"> Plectorhynicus gaterinus</Emphasis> (Forsskal, 1775) in the Red Sea,Egypt

A new myxosporean parasite, Myxobolus stomum n. sp., is described from the oral cavity and lips of the blackspotted grunt Plectorhynicus gaterinus (Forsskal, 1775) in the Red Sea, Egypt. The parasite was observed as tiny aggregates of whitish cysts hardly noticed within the muscles of the oral cavity, especially within the lips. The spores were subspherical and measured 8.5×6.5 m. Polar capsules were equal, pear-shaped, occupied about half of the spore length and measured 4.4×2.4 m. Histological evaluation of the infection revealed no significant impact on the host. The ultrastructure of the plasmodial wall and sporogenesis of the present species followed the usual pattern valid for most studied myxosporean species.     

<Emphasis Type="Italic">Trypanosoma</Emphasis> (<Emphasis Type="Italic">Herpetosoma</Emphasis>) <Emphasis Type="Italic">kuseli</Emphasis> sp. n. (Protozoa: Kinetoplastida) in Siberian flying squirrels (<Emphasis Type="Italic">Pteromys volans</Emphasis>)

All trypanosome species classified in the subgenus Herpetosoma in sciurid hosts have been recorded from ground and tree squirrels to date, but not from any flying squirrels. We describe in this paper a novel trypanosome species, Trypanosoma (Herpetosoma) kuseli sp. n., from Siberian flying squirrels (Pteromys volans) imported from China, and compare it with T. (H.) otospermophili in Richardson's ground squirrels (Spermophilus richardsonii) and Columbian ground squirrels (Spermophilus columbianus) from the USA. Due to a short free flagellum, the new species appeared stumpy compared with T. otospermophili (length of free flagellum 7.0 +/- 0.8 microm, total length 32.1 +/- 0.8 microm, n = 13 and length of free flagellum 15.5 +/- 1.6 microm, total length 35.9 +/- 1.0 microm, n = 13, respectively). Another conspicuous morphological feature of the new species was an anteriorly positioned kinetoplast, found approximately at the midpoint between the nucleus and the posterior end. These characters have not been recorded from any squirrel Herpetosoma trypanosome species. Comparison of the nucleotide sequences of the small and large subunit rRNA genes indicated that T. kuseli sp. n. was more homologous to T. otospermophili than murid Herpetosoma species, such as T. grosi, T. lewisi, T. musculi, T. microti and T. evotomys.     

Light and electron microscopic studies on <Emphasis Type="Italic">Myxobolus egyptica</Emphasis> sp. nov. (Myxozoa,Myxosporea), infecting the hornlip mullet <Emphasis Type="Italic">Oedalechilus labiosus</Emphasis> from the Red Sea

A new myxosporean, Myxobolus egyptica sp. nov., was described from the gills of the hornlip mullet Oedalechilus labiosus, collected from the Red Sea at Al-Quseir city, Egypt. The prevalence of infection was 12/72 (16.66%). Myxobolus egyptica was identified on the basis of spore morphometry, histology and transmission electron microscopy. It was distinguished from all previously reported Myxobolus spp. by its shape, dimensions of the mature spore 10.0 ± 0.6 (9.5–10.5) μm in length, 8.5 ± 0.4 (8.0–9.0) μm in width and 8.7 ± 0.5 (8.4–9.2) μm in thickness, polar capsules, locality and host. The parasite formed intrafilamental cyst-like plasmodia. These plasmodia caused curling and atrophy of the gill lamellae. The ultrastructural analysis revealed a double-unit plasmodial membrane which was in direct contact with the host cells and had numerous vesicles. Some mitochondria were found below this membrane. The disporic pansporoblast was earliest recognizable stage of sporogenesis. Advanced developmental stages of spores and mature spores were reported.     

<Emphasis Type="Italic">Kudoa unicapsula</Emphasis> n. sp. (Myxosporea: Kudoidae) a parasite of the Mediterranean mullets <Emphasis Type="Italic">Liza ramada</Emphasis> and <Emphasis Type="Italic">L. aurata</Emphasis> (Teleostei: Mugilidae)

A new multivalvulid myxozoan parasite, Kudoa unicapsula n. sp., is described from the intestinal mesentery, intestine and pyloric caeca of the thin-lipped grey mullet Liza ramada (Risso 1826) and the golden grey mullet L. aurata (Risso, 1810) from the Mediterranean coastal waters of Spain. It is characterized by the presence of elongated, rice corn-like white cysts of 0.47–0.56 × 0.18–0.38 mm, filled with tetracapsulate, slightly asymmetric spores, rectangular in apical view and tear-shaped in lateral view with four polar capsules of considerably different size and slightly unequal spore valves with rounded edges, overlapping each other on the apex of the spore. One large polar capsule includes a polar filament coiled in two to three turns, and the other three polar capsules, which are very small, posses only a rudimental filament. Both light and electron microscopy data showed that this species differs from all previously described Kudoa spp. with unequal polar capsules. The molecular analysis based on 18S and 28S ribosomal deoxyribonucleic acid DNA sequence data of K. unicapsula n. sp. indicates a close relationship and thus phylogenetic clustering together with K. trifolia, a myxozoan from the same host and the same geographical location.     

Cysteine proteinases from promastigotes of <Emphasis Type="Italic">Leishmania</Emphasis> (<Emphasis Type="Italic">Viannia</Emphasis>) <Emphasis Type="Italic">braziliensis</Emphasis>

Leishmania (Viannia) braziliensis is the major causative agent of American tegumentary leishmaniasis, a disease that has a wide geographical distribution and is a severe public health problem. The cysteine proteinase B (CPB) from Leishmania spp. represents an important virulence factor. In this study, we characterized and localized cysteine proteinases in L. (V.) braziliensis promastigotes. By a combination of triton X-114 extraction, concanavalin A-affinity, and ion exchange chromatographies, we obtained an enriched fraction of hydrophobic proteins rich in mannose residues. This fraction contained two proteinases of 63 and 43 kDa, which were recognized by a CPB antiserum, and were partially sensitive to E-64 in enzymatic assays with the peptide Glu-Phe-Leu. In confocal microscopy, the CPB homologues localized in the peripheral region of the parasite. This data together with direct agglutination and flow cytometry assays suggest a surface localization of the CPB homologues. The incubation of intact promastigotes with phospholipase C reduced the number of CPB-positive cells, while anti-cross-reacting determinant and anti-CPB antisera recognized two polypeptides (63 and 43 kDa) derived from phospholipase C treatment, suggesting that some CPB isoforms may be glycosylphosphatidylinositol-anchored. Collectively, our results suggest the presence of CPB homologues in L. braziliensis surface and highlight the need for further studies on L. braziliensis cysteine proteinases, which require enrichment methods for enzymatic detection.     

Redescription of <Emphasis Type="Italic">Lemuricola</Emphasis> (<Emphasis Type="Italic">Madoxyuris</Emphasis>) <Emphasis Type="Italic">bauchoti</Emphasis> (Nematoda,Oxyuridae) from <Emphasis Type="Italic">Lemur catta</Emphasis> in Madagascar

Lemuricola (Madoxyuris) bauchoti Chabaud, Brygoo et Petter, 1965 is redescribed from material collected from the ring-tailed lemur, Lemur catta, from the Beza Mahafaly Special Reserve in Madagascar using the scanning electron microscope. This is a new host record and the first oxyurid reported from the ring-tailed lemur. Previously, records of each species of the subgenus Madoxyuris have been restricted to a single host species, but the close relationship between these nematodes and their Strepsirrhini hosts will only be proven when additional records fill in the gaps in their distribution.     

Cercarial shedding from <Emphasis Type="Italic">Galba</Emphasis><Emphasis Type="Italic">truncatula</Emphasis> infected with <Emphasis Type="Italic">Fasciola</Emphasis><Emphasis Type="Italic">gigantica</Emphasis> of distinct geographic origins

Galba truncatula snails were experimentally infected with either of two different isolates of Fasciola gigantica, originating from Egypt or China, to determine the influence of these isolates on the characteristics of snail infections. The survival rates of G. truncatula on day 30 post-exposure were 90.0% and 60.2% in the Egyptian and Chinese groups, respectively. The frequency of cercaria-shedding snails within the Egyptian group was 79.8%, whereas in the Chinese group it was 22.4%. The parasite origin had a significant effect on the durations of the prepatent and patent periods. The mean number of cercariae shed from the Egyptian group was significantly greater than that shed from the Chinese group (a mean of 275.5 per cercaria-shedding snail compared with 29.0). These results could be explained by the fact that G. truncatula might be a natural intermediate host for F. gigantica in Egypt, and the greater adaptability of the Egyptian miracidia of F. gigantica to unusual snail hosts. These results demonstrate the influence of the geographic origin of the parasite on the success of trematodes infecting snails.     

<Emphasis Type="Italic">Myxobolus honghuensis</Emphasis> n. sp. (Myxosporea: Bivalvulida) parasitizing the pharynx of allogynogenetic gibel carp <Emphasis Type="Italic">Carassius auratus gibelio</Emphasis> (Bloch) from Honghu Lake,China

Myxobolus honghuensis n. sp. is described from allogynogenetic gibel carp Carassius auratus gibelio (Bloch), during a survey of myxosporean parasites in Honghu Lake, Hubei Province, China. It is characterized by the presence of round plasmodia of 5–12 mm in diameter in the pharynx of host. Mature spores of M. honghuensis were pyriform in frontal view and anterior pointed with bluntly round posterior, they measured 16.9 ± 0.5 (15.1–19.5) μm long, 10.4 ± 0.4 (9.0–11.3) μm wide, and 8.4 ± 0.4 (7.9–9.1) μm thick. Two polar capsules were pyriform and slightly unequal with larger polar capsule 8.4 ± 0.4 (7.6–10.2) μm × 3.9 ± 0.2 (3.0–4.5) μm and smaller capsule 7.9 ± 0.2 (7.0–9.3) μm × 3.7 ± 0.3 (2.8–4.1) μm. Polar filaments coiled with seven to eight turns. Both morphology and DNA sequence data revealed that M. honghuensis n. sp. was distinct from other described Myxobolus species. Phylogenetic analysis placed M. honghuensis n. sp. in a clade of gill-infecting myxobolids.     

<Emphasis Type="Italic">Leishmania</Emphasis> (<Emphasis Type="Italic">Viannia</Emphasis>) <Emphasis Type="Italic">shawi</Emphasis> purified antigens confer protection against murine cutaneous leishmaniasis

Objective  

Leishmania (Viannia) shawi was characterized only recently, and few studies concerning the immunogenic and protective properties of its antigens have been performed. The present study aimed to evaluate the protective potential of the five antigenic fractions isolated from L. (V.) shawi promastigotes in experimental cutaneous leishmaniasis.     

Subcellular localization of an extracellular serine protease in<Emphasis Type="Italic"> Leishmania</Emphasis> (<Emphasis Type="Italic">Leishmania</Emphasis>)<Emphasis Type="Italic"> amazonensis</Emphasis>

Extracellular proteolytic activity was detected in a Leishmania (L.) amazonensis culture supernatant and a 56-kDa protein was purified using (NH₄)₂SO₄ precipitation followed by affinity chromatography on aprotinin–agarose. A rabbit serum obtained against the 56-kDa extracellular serine protease was used in order to analyze its location in L. (L.) amazonensis parasites. Immunocytochemistry studies revealed that the enzyme is mainly found in the flagellar pocket and cytoplasmic vesicles of promastigote forms, whereas in amastigotes, it is located in electron-dense structures resembling megasomes. These results indicate that the 56-kDa serine protease is released into the extracellular environment through the flagellar pocket; and its intracellular location suggests either a correlated enzymatic activity or intracellular trafficking.     

Classical and molecular cytogenetics of <Emphasis Type="Italic">Khawia sinensis</Emphasis> (Cestoda: Caryophyllidea), invasive parasite of carp, <Emphasis Type="Italic">Cyprinus carpio</Emphasis>

Chromosomes of the invasive tapeworm Khawia sinensis (Caryophyllidea), the specific parasite of common carp, were analyzed by means of conventional Giemsa staining and using fluorescent DAPI and YOYO-1 dyes, silver staining, and fluorescent in situ hybridization (FISH) with 18S rDNA probe. The karyotype is composed of eight pairs of metacentric and telocentric chromosomes (2n = 16, n = 3m + 5t, TCL = 42.54 μm). Constitutive heterochromatin was located at pericentromeric regions of all pairs, except for the largest metacentric pair (no. 1), which possessed no DAPI-positive band. FISH with rDNA probe revealed that both homologues of chromosome pair no. 6 carry a cluster of ribosomal arrays, which were located interstitially close to the centromere. Present results are compared with previous cytogenetic data on Khawia spp., and comments are made on the karyotypes with respect to their phylogenetic links.     

Functional polymorphisms in <Emphasis Type="Italic">XRCC</Emphasis>-<Emphasis Type="Italic">1</Emphasis> and <Emphasis Type="Italic">APE</Emphasis>-<Emphasis Type="Italic">1</Emphasis> contribute to increased apoptosis and risk of ulcerative colitis

Objective  

The present study was designed to investigate the role of X-ray cross-complementing group 1 (XRCC1) and apurinic/apyrimidinic endonuclease 1 (APE1) polymorphisms in apoptosis and the risk of ulcerative colitis (UC).     

Antiviral biflavonoids from <Emphasis Type="Italic">Radix Wikstroemiae</Emphasis> (<Emphasis Type="Italic">Liaogewanggen</Emphasis>)

Background  

Radix Wikstroemiae is a common Chinese herbal medicine. The ethyl acetate fraction of the ethanolic extract of W. indica possesses potent in vitro antiviral activity against respiratory syncytial virus (RSV). This study aims to identify the antiviral components of the active fraction.     

<Emphasis Type="Italic">P</Emphasis>. <Emphasis Type="Italic">aeruginosa</Emphasis> Biofilms in CF Infection

Pseudomonas aeruginosa is an opportunistic pathogen of immunocompromised hosts. In cystic fibrosis (CF), P. aeruginosa causes acute and chronic lung infections that result in significant morbidity and mortality. P. aeruginosa possesses several traits that contribute to its ability to colonize and persist in acute and chronic infections. These include high resistance to antimicrobials, ability to form biofilms, plethora of virulence products, and metabolic versatility. In P. aeruginosa, a cell-to-cell communication process termed quorum sensing (QS) regulates many of these factors that contribute to its pathogenesis. Recent evidence suggests that the CF lung environment presents a specialized niche for P. aeruginosa. The relationship of P. aeruginosa QS, biofilm formation, and the CF lung environment is discussed.     

Scanning electron microscopy of<Emphasis Type="Italic"> Ithyoclinostomum dimorphum</Emphasis> (Trematoda: Clinostomidae), a parasite of<Emphasis Type="Italic"> Ardea cocoi</Emphasis> (Aves: Ardeidae)

Scanning electron microscopy is used for the first time to study the surface topography of Ithyoclinostomum dimorphum (Diesing, 1850), collected from Ardea cocoi Linnaeus, 1766 on the floodplain of the upper Paraná River Basin, Brazil. The body surface exhibits annular furrows, ridges and sensory papillae but no spines, and the tegument is reticulate. The oral sucker is terminal, bears radial furrows and is surrounded by a collar. The ventral sucker is located close to the oral sucker but lacks a collar. When extruded, the cirrus can be seen to bear papillae in its base, and the aperture of the ejaculatory duct is visible distally. The excretory pore is dorso-subterminal. Various incrustations and secretions are present on the body surface. These detailed observations make it possible for to us speculate on the functional significance of some of our findings in relation to the large size and contractile nature of these worms, and their ability to survive and mate in an apparently hostile environment.     

Ultrastructure of the spermatozoon of <Emphasis Type="Italic">Acanthostomum spiniceps</Emphasis> (Digenea: Acanthostomidae), a parasite of <Emphasis Type="Italic">Bagrus</Emphasis> spp. (Siluriformes:Bagridae)

The present study describes, for the first time, the sperm ultrastructure of the parasite Acanthostomum spiniceps (Digenea: Acanthostomidae). The adult worms of this species were collected from the freshwater fishes, Bagrus bayad and Bagrus docmac, caught from the Damietta branch of the River Nile in Dakahlia Governorate, Egypt. Ultrastructure of the sperm of this species revealed that it can be differentiated into seven regions. It is characterized by its filiform shape, tapers anterior, and posterior ends; the two axonemes are in close contact with the plasma membrane and the presence of two mitochondria as one anterior and the other is posterior. The two mitochondria are parallel at a short distance enclosing the first part of nucleus in between. The nucleus is characteristically formed of unusual network of chromatin which is vacuolated. The spermatozoon of A. spiniceps is similar to that of most parasitic Platyhelminthes.