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At least 19 recordsLinked to original sources
PubMed1992

Treatment of fish parasites. 9. Effects of a medicated food containing malachite green on Ichthyophthirius multifiliis Fouquet, 1876 (Hymenostomatida, Ciliophora) in ornamental fish.

For systemic therapy against trophozoites of the skin-inhabiting stage of Ichthyophthirius multifiliis in ornamental fish, the latter were fed medicated food flakes containing malachite green once daily for 1-11 days ad libitum. Naturally or artificially infected cardinal tetras (Paracheirodon axelrodi), blue gouramis (Trichogaster trichopterus), or clown loach (Botia macracantha) were used in the trials. The fish were maintained in aerated 12.5- or 60-1 aquaria at 23 degrees C. Ultrastructural investigations (scanning and transmission electron microscopy) revealed clear deleterious effects of malachite green on the parasitic stages. Following the initial application, the inner membrane of the mitochondria was destroyed. In fish fed for 2 days, aggregation of the mucocysts and polymerization the microtubules within the macronucleus occurred. Finally, the trophozoite's membrane was completely destroyed. In fish fed for 4 days, the medicated food killed all trophozoites of I. multifiliis. Sensitive ornamental fish (e.g., P. axelrodi) showed no adverse effects after they had been fed with only the medicated food flakes for 2 months. Therefore, the oral administration of malachite green using this newly developed medicated food considerably reduces the risk of toxic effects on the fish hosts, which are sometimes caused by malachite green following its application by immersion therapy. The feeding of flakes medicated with malachite green provides and easy-to-handle and highly effective treatment of I. multifiliis in ornamental fish.

Animal Feed↗
PubMed1985

5S and 5.8S ribosomal RNA evolution in the suborder Tetrahymenina (Ciliophora: Hymenostomatida).

The nucleotide sequences of the 5S and 5.8S rRNAs of eight strains of tetrahymenine ciliates have been determined. The sequences indicate a clear distinction between Tetrahymena paravorax and its suggested conspecific T. vorax, but leave the taxonomic distinction between T. vorax and T. leucophrys in doubt. The rRNA sequences of six Tetrahymena species and of three other species of the suborder Tetrahymenina have been used to deduce evolutionary schemes in which ancestral rRNA sequences and changes are proposed. These schemes suggest the predominant acceptance of G----A and C----T transitions in the 5S rDNA during the evolution of the suborder.

Animals↗
PubMed1996

Raising activity of Bacillus thuringiensis var. israelensis against Anopheles stephensi larvae by encapsulation in Tetrahymena pyriformis (Hymenostomatida:Tetrahymenidae).

Toxicity of Bacillus thuringiensis var israelensis (B.t.i.) against surface-feeding mosquito larvae of Anopheles stephensi was enhanced by encapsulation in the protozoan Tetrahymena pyriformis. In the laboratory, larvae died about 8 times faster when exposed to protozoan cells filled with B.t.i. than when exposed to the same concentrations of B.t.i. alone. Best larvicidal activities were achieved with ratios of 1:200-1:500 T. pyriformis cells to B.t.i. spores. The concentration of B.t.i. needed to kill 50% of exposed populations was 4-fold lower with T. pyriformis than with B.t.i. alone in 100 ml-test cups. Toxicity enhancement is very likely a consequence of concentrating B.t.i. insecticidal crystal proteins in T. pyriformis cells and floating them to the water surface in the larval feeding zone. Reduction in the exposure time of B.t.i. to unfavorable field conditions, as a result of the decrease in larval mortality time, might improve the persistence of this biological control agent in nature.

Animals↗
PubMed2005

Ophryoglena hemophaga n. sp. (Ciliophora: Ophryoglenidae): a parasite of the digestive gland of zebra mussels Dreissena polymorpha.

Ophryoglena hemophaga n. sp. is described from a freshwater Dreissena polymorpha population in the Rhine delta of the Netherlands. This is the first ophryoglenine species (order Hymenostomatida, suborder Ophryoglenina) recorded as a molluscan parasite. As is typical of ciliates in the suborder Ophryoglenina, O. hemophaga exhibits a polymorphic life history with cystment and reproduction by palintomy. Trophonts were observed within digestive gland lumina, and zebra mussel hemocytes were present in some of their digestive vacuoles. The presence of a single, longitudinal tract of multiple contractile vacuoles represents its most unique feature and distinguishes it from all other described Ophryoglena spp. The number of somatic kineties of O. hemophaga (range 100 to 124) is also distinguishing as it is one of the lowest for [corrected] an Ophryoglena sp. Other characteristics of this species include: ovoid to elongate trophonts 96 to 288 microm in length, with an elongate macronucleus 41 to 65 microm in length; tomonts 50 to 150 microm in diameter producing a clear mucous cyst envelope, whose thickness is approximately half of the tomont diameter; elongated theronts 96 to 131 microm in length which emerge after 1 to 3 cell divisions taking 36 to 48 h at 20 +/- 3 degrees C. Protomonts and theronts are, respectively, negatively and positively phototactic--characteristics that likely aid in maintenance of infection in zebra mussel populations.

Animals↗
PubMed2005

Non-invasive detection and quantification of the parasitic ciliate Ichthyophthirius multifiliis by real-time PCR.

The main parasitic threat to freshwater fish is the ciliate Ichthyophthirius multifiliis. We developed a real-time PCR assay using SYBR Green intercalating fluorescent dye for rapid detection and quantification of I. multifiliis. This non-invasive assay was based on the quantification of I. multifiliis free-swimming stages from filtered water samples, and thus made it possible to preserve host individuals. An alignment of 18S rDNA sequences of I. multifiliis and related species of the ciliate order Hymenostomatida was used to design amplification primers specifically targeting the I. multifiliis 18S rDNA gene. Different standard curves consisting of 2-fold serial dilutions of DNA extracted from 20, 60, 100 and 1000 I. multifiliis cells were constructed. The assay was able to detect less than 0.5 cell equivalent and showed a strong linearity (R2 = 0.984). Water samples were collected from 2 tanks containing heavily infected and apparently uninfected Carassius auratus specimens and were used to test this technique. Positive signals were obtained from water samples collected from both tanks, with a deduced concentration ranging from 3 to 58 I. multifiliis cells l(-1). The assay can detect low concentrations of the parasite in water, presumably corresponding to an early phase of the disease. It may, thus, be a valuable tool in assisting in the monitoring and control of ichthyophthiriasis in aquaculture.

Animals↗
PubMed1981

Functional and phylogenetic aspects of the ciliary membrane: a comparative freeze-fracture study.

This paper illustrates the structural diversity of the ciliary membrane of the somatic ciliature in 68 ciliate genera and describes the interior architecture of several presumptive sensory cilia. Freeze-fracture technique reveals a variety of intramembrane particle arrays known as ciliary necklace, ciliary plaques, and ciliary rosettes. While the function of these arrays is still largely unknown, their distribution among ciliates suggests a phylogenetic correlation. Whereas current systems of ciliate classification are primarily based on the character of the ciliature which surrounds the cytostome as well as on the morphogenesis of this oral ciliature, the data presented in this paper are well suited to emphasize the significance of the somatic ciliature for the reconstruction of ciliate phylogeny. This is particularly evident when the freeze-fracture data are mapped in parallel with a simplified phylogenetic tree based on the appearance of both the oral and the somatic ciliature. The freeze-fracture data are in agreement with hypothesis of a non-hymenostome origin of the spirotrichs and suggest a close relationship with respect to the origin of the Hymenostomatida from the Colpodida instead of from the Nassulida. The presumptive sensory cilia show a significantly greater particle density than most somatic cilia. While the particles may represent receptor proteins or ion channels, with the freeze-fracture technique it is at present impossible to specify the modalities of such "sensory" cilia.

Animals↗
PubMed1994

Architecture of telomerase RNA.

Telomerase, an essential ribonucleoprotein reverse transcriptase, adds telomeric DNA to the ends of eukaryotic chromosomes. We examined the conformational properties of the naked RNA moiety of telomerase from two related ciliates, Tetrahymena thermophila and Glaucoma chattoni. As well as finding evidence for features proposed previously on the basis of phylogenetic comparisons, novel conserved structural properties were revealed. Specifically, although the region around helix III was previously proposed to form a pseudoknot, our results indicate that in the naked RNA this region maintains a level of 'plasticity', probably in an equilibrium favoring one of two helices. In addition, these studies reveal that the templating domain is not entirely single-stranded as previously proposed, but is ordered due to constraints imposed by other parts of the RNA. Finally, our results suggest that the GA bulge in helix IV may introduce a structurally conserved kink. We now propose a 'two-domain' structure for the telomerase RNA based on function: one conformationally flexible domain, which includes the template and the region around helix III, involved with enzymatic function, and a second largely helical domain, including helices I and IV and the proposed kink, which may serve as a scaffold for protein binding.

Animals↗
PubMed2002

Immunisation of channel catfish, Ictalurus punctatus, with Ichthyophthirius multifiliis immobilisation antigens elicits serotype-specific protection.

Surface immobilisation antigens (i-antigens) were purified from two strains of Ichthyophthirius multifiliis (NY1 and G5) that represent different i-antigen serotypes, namely A and D, respectively. The efficacy of the purified antigens as subunit vaccines was then tested in challenge studies using parasites of the homologous or heterologous serotype. Three groups of juvenile channel catfish (70 animals per group) were immunised with i-antigens from either the G5 or NY1 isolates, or with bovine serum albumin (BSA) as a control. Proteins were injected intraperitoneally (i.p.) at a dose of 10 microg/fish with complete Freund's adjuvant on day 1, followed by a second injection in incomplete Freund's adjuvant on day 15. Fish immunised with the purified i-antigens developed high titres of serum immobilising antibodies whereas sera from BSA-injected control fish did not. Fish antisera immobilised parasites of the homologous, but not the heterologous strain, and recognised the corresponding i-antigens on Western blots run under non-reducing conditions. On day 36, each group was divided into two subgroups (n=30). One subgroup was challenged with G5 parasites, and the other was challenged with NY1 parasites. When challenged with G5 parasites, 70% of fish immunised with the G5 i-antigens survived. When challenged with NY1 parasites, 33.3% of fish immunised with the NY1 i-antigens survived. All BSA-injected control fish died, as did all fish injected with the purified antigens and challenged with the non-homologous parasite strain. Statistical analyses indicated significant differences among test and control groups with regard to the mean days to death (MDD). While the results of these studies clearly support a role for i-antigens in protection, active immunity in response to natural infection is not serotype-specific. The utility of i-antigens, as well as the existence of other potential vaccine candidates for the prevention of 'white-spot' disease, are discussed.

Amino Acid Sequence↗
PubMed2000

Characterization of histone H3/H4 gene region and phylogenetic affinity of Ichthyophthirius multifiliis based on H4 DNA sequence variation.

We sequenced the amino-terminal third of the histone H3 and H4 genes and the intergenic region from Ichthyophthirius multifiliis. Fourteen recombinant clones of 646 bp were sequenced and the level of sequence variation detected among these clones was similar to that reported among closely related species of Tetrahymena and to levels of sequence variation detected within other ciliates. The intergenic region is 417 bp and approximately 92% AT rich, making it the longest and most AT-rich ciliate H3/H4 intergenic region yet identified. Similar to Tetrahymena, the intergenic region of Ichthyophthirius contains two CCAAT regions arranged in a complementary orientation. A neighbor-joining tree was constructed based on nucleotide sequence variation among H4 genes to evaluate evolutionary relationships within and among six classes of Ciliophora. The single shortest neighbor-joining tree depicted a sister-group relationship of Ichthyophthirius with taxa of Tetrahymenina, thereby supporting monophyly of Oligohymenophorea.

Amino Acid Sequence↗
PubMed1993

Processing of food vacuoles in the parasitic ciliate Ichthyophthirius multifiliis after exit from the host.

The digestive cycle of the fish parasite Ichthyophthirius multifiliis (Ciliophora) can be divided into three main stages. During stage A the vacuoles are not yet condensed. This stage can be subdivided into an early phase in which food vacuoles contain almost intact fish cells and a later phase in which dense material accumulates at the periphery of the vacuoles. At stage B, food vacuoles attain a very high density, and at stage C the vacuole expands when the membrane pulls away from a condensed mass of substances in digestion. After its exit from the host the parasite encysts and divides, but new food vacuoles are not formed during this phase of the life cycle. Type A vacuoles are the first to disappear after exit from the host. The percentage of type B vacuoles increases during the first few hours of free life, decreasing later when the percentage of type C vacuoles starts to increase. At the end of the division phase, type C vacuoles are the most common. Food-vacuole egestion was observed only 20 h after exit from the host. At the theront stage, food vacuoles were not evident, but small vacuoles with acid phosphatase activity were observed.

Animals↗
PubMed2004

Effects of crude extracts of Mucuna pruriens (Fabaceae) and Carica papaya (Caricaceae) against the protozoan fish parasite Ichthyophthirius multifiliis.

The ciliate Ichthyophthirius multifiliis is among the most pathogenic parasites of fish maintained in captivity. In the present study, the effects of the crude methanolic extract of leaves of Mucuna pruriens and the petroleum-ether extract of seeds of Carica papaya against I. multifiliis were investigated under in vivo and in vitro conditions. Goldfish (Carassius auratus auratus) infected with the parasites were immersed for 72 h in baths with M. pruriens extract, and for 96 h in baths with C. papaya extract. There was a 90% reduction in numbers of I. multifiliis on fish after treatment in baths of each plant extract at 200 mg l(-1 )compared to untreated controls. Consequently, parasite-induced fish mortality was reduced significantly. A complete interruption of trophont recruitment was achieved by immersion in the M. pruriens extract. In vitro tests led to a 100% mortality of I. multifiliis in 150 mg/l M. pruriens extract, and in 200 mg/l of C. papaya extract after 6 h. Although the active constituents of the medicinal plant extracts are still unknown, we have demonstrated that they have potential for effective control of I. multifiliis.

Animals↗
PubMed1996

The control of ichthyophthiriasis by a medicated food containing quinine: efficacy tests and ultrastructure investigations.

The present report demonstrates that a medicated food containing quinine kills the skin-inhabiting trophozoite stage of Ichthyophthirius multifiliis in ornamental fish. Artificially infected swordtails. (Xiphophorus helleri), black mollies (Poecilia sphenops), and black neons (Hyphessobrycon herbertaxelrodi) were used in the trials. The fish were maintained in groups of 10 or 20 inside aquaria (20 or 60 l) at 25 degrees C. Ultrastructure investigations by means of transmission electron microscopy revealed clear deleterious effects of quinine on the trophozoite stages. Following the initial application the outer limiting membrane of the trophozoite was broken at places. Within the nephridial plasma the plasma bridges were broken in part. After 2 days of treatment the lumen of the alveolar sac became enlarged. The food vacuoles in treated trophozoites were more electron-dense than those in the untreated controls. Numerous lipid droplets were found close to the vacuoles. The degree of damage in the nephridial plasma was intensified. When feeding was prolonged for 3 or more days, all kinds of damage became more extensive as seen in the trophozoites after 1 or 2 days of treatment. In addition food vacuoles in the final stages of digestion were no longer detectable. In long-term feeding tests, when typical ornamental fish species were fed three times daily ad libitum with the medicated food over a 12-week period, the animals showed no adverse clinical symptom. From the toxicological as well as the ecological and economical point of view the feeding of flakes containing quinine has considerable advantages as compared with conventional bath treatment.

Administration, Oral↗
PubMedDate not supplied

The cellular proliferative response, humoral antibody response, and cross reactivity studies of Tetrahymena pyriformis with Ichthyophthirius multifiliis in juvenile carp (Cyprinus carpio L.).

The immune response of 10-12-week-old juvenile carp to T. pyriformis [CCAP 1630/w, 1939 (w)] was investigated. The humoral antibody response following one and two intraperitoneal injections of whole live T. pyriformis (protein concentration of 25 micrograms/g body weight), separated by an interval of 4 weeks, was monitored over 12-16 weeks. Peak antibody titres were detected 6 weeks following antigen administration. Antibody titres were elevated following the second injection, and relatively high levels were still maintained by week 16. Proliferative responses measured by autoradiography following intraperitioneal injection of methyl 3H thymidine (1-2 microCi/g body weight) were recorded in the pronephros, opisthonephros, and spleen at weekly intervals for 4 weeks following each injection of T. pyriformis. Immunised fish had higher counts than nonimmunised controls, with the greatest counts occurring at 2 and/or 3 weeks following one injection of antigen and 2 weeks following two injections. Activity was recorded prior to peak antibody production with the pronephros and opisthonephros having greater proliferative responses than the spleen. Cross antigenicity studies to examine protection of carp against I. multifiliis following administration of T. pyriformis, showed little evidence in support of protection using this strain of T. pyriformis. Further, antisera raised in either carp, rabbits, or rats failed to show any cross antigenicity between these two species of protozoa.

Animals↗
PubMed1993

Localized leucocyte response to Ichthyophthirius multifiliis establishment in immune carp Cyprinus carpio L.

O-group carp (Cyprinus carpio) which had been immunized against Ichthyophthirius multifiliis by controlled infections were challenged by topical application of theronts to the caudal fin. The parasites which established were examined ultrastructurally, and host leucocyte responses were compared with those observed in primary infections. In the primary exposure group eosinophils and (to a lesser extent) basophils were the predominant cells infiltrating infection sites. In contrast, parasite development in immunized fish initiated localized leucocytic infiltrations which were dominated by eosinophilic granular cells (EGCs) and basophils. Greater localized phagocytosis was recorded in immunized fish by neutrophils, macrophages and resident epidermal filament cells. In vitro studies indicated that pronephric leucocytes from immunized fish displayed enhanced non-specific phagocytosis. In the skin, leucocytes were observed in close proximity to the trophozoite surface in both immunized and primary exposure fish, often undergoing lysis and release of cellular contents. However, there was no evidence of active cell adherence nor of any cell-mediated damage incurred to the parasite in either case. These observations are discussed in relation to the possible role of leucocytes in mediating pathogenesis and immune responses.

Animals↗
PubMed2004

Expression of pro-inflammatory cytokines in rainbow trout (Oncorhynchus mykiss) during an infection with Ichthyophthirius multifiliis.

Inflammatory processes are known to take place in the skin of fish during an infection with the parasitic ciliate Ichthyophthirius multifiliis. The present study shows that the pro-inflammatory cytokines interleukin 1 beta (IL-1beta) and tumor necrosis factor alpha (TNF-alpha), the chemokine interleukin 8 (IL-8) and the type II IL-1 receptor (IL-1RII) are expressed in rainbow trout during an infection. In the skin an up to 17.8 times increase in the expression level of IL-1beta relative to uninfected controls was seen 4 days after infection. Upregulated expression of IL-1beta was likewise observed in the head kidney and spleen during the infection although to a lesser degree. TNF-alpha expression was seen in all examined tissues, with an increase in transcript level in the skin of up to 3.2 times the level in uninfected fish. A significant increase in the expression of IL-8 was evident in the skin and also to a lower extent in the head kidney and spleen. Expression of the down regulatory IL-1RII was seen in all three tissues. The potential involvement of the expression of these genes and their relevance in an infection with I. multifiliis are discussed.

Animals↗
PubMed2006

Cross-immunity and antibody responses to different immobilisation serotypes of Ichthyophthirius multifiliis.

Vaccination of channel catfish with either of two serotypes of the parasitic ciliate Ichthyophthirius multifiliis conferred protection against challenge infection by either serotype. Fish were vaccinated by intracoelomic injection with live theronts of isolate G5 (serotype D) or isolate G12 (a new serotype), which express different surface immobilisation antigens. Vaccination with live G12 theronts conferred complete protection against subsequent challenge by both serotypes while vaccination with G5 theronts elicited only partial protection against both serotypes. Vaccination with trophont lysates did not protect against challenge infection. Sera from vaccinated fish were tested in immobilisation assays, ELISAs, and Western blots. Serum antibodies recognised only immobilisation antigens of the serotype used for vaccination in immobilisation assays or on Western blots. No antigens common to both serotypes were identified by Western blots. In contrast, serum antibodies bound antigens in cell lysates from both serotypes by ELISA, demonstrating that antibodies recognising both serotypes are produced in response to infection, which presumably confer observed cross-serotype protection.

Animals↗