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Sample records for mesocestoides corti platyhelminthes

  1. Expression of the histone chaperone SET/TAF-Iβ during the strobilation process of Mesocestoides corti (Platyhelminthes, Cestoda).

    PubMed

    Costa, Caroline B; Monteiro, Karina M; Teichmann, Aline; da Silva, Edileuza D; Lorenzatto, Karina R; Cancela, Martín; Paes, Jéssica A; Benitz, André de N D; Castillo, Estela; Margis, Rogério; Zaha, Arnaldo; Ferreira, Henrique B

    2015-08-01

    The histone chaperone SET/TAF-Iβ is implicated in processes of chromatin remodelling and gene expression regulation. It has been associated with the control of developmental processes, but little is known about its function in helminth parasites. In Mesocestoides corti, a partial cDNA sequence related to SET/TAF-Iβ was isolated in a screening for genes differentially expressed in larvae (tetrathyridia) and adult worms. Here, the full-length coding sequence of the M. corti SET/TAF-Iβ gene was analysed and the encoded protein (McSET/TAF) was compared with orthologous sequences, showing that McSET/TAF can be regarded as a SET/TAF-Iβ family member, with a typical nucleosome-assembly protein (NAP) domain and an acidic tail. The expression patterns of the McSET/TAF gene and protein were investigated during the strobilation process by RT-qPCR, using a set of five reference genes, and by immunoblot and immunofluorescence, using monospecific polyclonal antibodies. A gradual increase in McSET/TAF transcripts and McSET/TAF protein was observed upon development induction by trypsin, demonstrating McSET/TAF differential expression during strobilation. These results provided the first evidence for the involvement of a protein from the NAP family of epigenetic effectors in the regulation of cestode development. PMID:25823644

  2. Early post-larval development of the endoparasitic platyhelminth Mesocestoides corti: trypsin provokes reversible tegumental damage leading to serum-induced cell proliferation and growth.

    PubMed

    Espinoza, I; Galindo, M; Bizarro, C V; Ferreira, H B; Zaha, A; Galanti, N

    2005-11-01

    Mesocestoides corti is a suitable in vitro model for studying the development of human endoparasitic platyhelminthes. Treatment with trypsin, supplemented with fetal bovine serum (FBS), induces M. corti development from larvae (tetrathyridia) to segmented adult worm; however, the role of this protease and of FBS in post-larval development induction remains unknown. To characterize the participation of trypsin enzymatic activity and of FBS in the induction of tetrathyridia growth and development, both stimuli were added to the larvae either together or sequentially. Additionally, specific inhibition of trypsin activity was also monitored. Finally, the effect of the enzyme on the parasite tegument as well as the proliferative activity and location of proliferating cells after induction of tetrathyridia development were also studied. We conclude that trypsin-induced tetrathyridia development to adult worm is FBS-dependent and that the effect of serum factors is dependent upon a previous trypsin-induced reversible damage to the larva tegument. In dividing and non-dividing tetrathyridia, proliferative activity of cells is mainly located within the apical massif in the anterior region and nerve cords of larvae, respectively. In tetrathyridia stimulated to develop to adult worms, an intense proliferative activity is evident along the nerve cords. Our results suggest that in natural infections the tetrathyridia tegument is temporally made permeable to growth factors by proteolytic enzyme activity in the intestine juice of the definitive host, thus leading to development to adult worms. PMID:15887242

  3. In vitro segmentation induction of Mesocestoides corti (Cestoda) tetrathyridia.

    PubMed

    Markoski, Mellssa M; Bizarro, Cristiano V; Farias, Sandra; Espinoza, Ingrid; Galanti, Norbel; Zaha, Arnaldo; Ferreira, Henrique B

    2003-02-01

    Mesocestoides corti is a suitable model for studying cestode development because of its ability to reproduce asexually and segment in vitro. The cultured parasite is also capable of sexual differentiation and, probably, reproduction. To establish conditions that increase the efficiency of in vitro M. corti larvae (tetrathyridia) segmentation, we tested the effects of an inducing agent and some physical parameters in cultures. We found that a 5% CO2-95% N2 gas phase, an incubation temperature of 39 C (instead of 37 C), and a 24-hr pretreatment with trypsin (10(5) BAEE/ml, BAEE = Na-benzoil-L-arginine ethyl ester unit of trypsin activity) in Roswell Park Memorial Institute (RPMI) 1640 medium supplemented with 20% fetal bovine serum (FBS) are able to increase individually or synergistically the segmentation rate of tetrathyridia. A segmentation rate of up to 100% was achieved on day 4 of culture, when all these conditions were used simultaneously, in comparison with an average rate of 40% obtained not before day 11 in cultures without any inducing treatment. Fetal bovine serum is essential for segmentation, and a concentration of 20% was established as the standard for induction. PMID:12659299

  4. In vitro culture of Mesocestoides corti metacestodes and isolation of immunomodulatory excretory-secretory products.

    PubMed

    Vendelova, E; Hrčková, G; Lutz, M B; Brehm, K; Nono Komguep, J

    2016-07-01

    Cestode-mediated diseases hold the interesting feature of persisting metacestode larvae dwelling within the host tissues, in the midst of the immune response. Excretory-secretory (ES) products of the metacestode larval stage modulate the host immune response and modify the outcome of the disease. Therefore, isolation and analysis of axenic metacestode ES products are crucial to study their properties. Here, we report the development of a system for long-term in vitro cultivation of the metacestode of the parasitic cestode Mesocestoides corti (syn. Mesocestoides vogae). Although feeder cells and host serum supported the early growth of the parasite, long-term survival was not dependent on host serum or host-derived factors enabling the collection of parasite released products in serum-free medium. Functionally, these axenic ES products recapitulated M. corti tetrathyridia's ability to inhibit LPS-driven IL-12p70 secretion by dendritic cells. Thus, our new axenic culture system will simplify the identification and characterization of M. corti-derived immunomodulatory factors that will indirectly enable the identification and characterization of corresponding factors in the metacestode larvae of medically relevant cestodes such as Echinococcus multilocularis that are not yet amenable to serum-free cultivation. PMID:27120409

  5. The toxicity of praziquantel against Mesocestoides vogae (syn. corti) tetrathyridia can be assessed using a novel in vitro system.

    PubMed

    Saldaña, Jenny; Casaravilla, Cecilia; Marín, Mónica; Fernández, Cecilia; Domínguez, Laura

    2003-04-01

    We recently standardised Mesocestoides vogae (syn. corti) tetrathyridia cultures in the presence of sodium taurocholate. Parasite clustering and segmentation were observed as taurocholate-dependent effects in biphasic and monophasic media, respectively, and both were inhibited by a specific minimum inhibitory concentration (m.i.c.) of the cestocidal drugs albendazol and praziquantel. In the present study, we analysed the relationship between clustering inhibition and drug toxicity using praziquantel and a mouse experimental infection. In an "in vitro-in vivo" trial, a significant (ANOVA, P<0.05) reduction was observed in the infectivity of tetrathyridia previously cultured with praziquantel m.i.c. (0.06 micro g/ml) for 10 days. In an "in vivo-in vitro" trial, the clustering of tetrathyridia recovered from mice treated with praziquantel was found to be markedly reduced: 22%, compared with 83% cluster-containing wells of parasites from control mice. These results show that the outcome of infection and the suppression of taurocholate-induced clustering provide consistent indications of praziquantel toxicity against M. vogae, an observation confirmed by histological studies. The easily recorded clustering inhibition of M. vogae tetrathyridia in biphasic medium is a potentially useful system for the assessment of drug toxicity against cestode larvae. PMID:12658458

  6. Mesocestoides lineatus (Goeze, 1782) (Mesocestoididae): new data on sperm ultrastructure.

    PubMed

    Miquel, Jordi; Eira, Catarina; Swiderski, Zdzisław; Conn, David Bruce

    2007-06-01

    Spermiogenesis and the ultrastructural characters of the spermatozoon of Mesocestoides lineatus are described by means of transmission electron microscopy, including cytochemical analysis for glycogen. Materials were obtained from a golden hamster (Mesocricetus auratus) after experimental infection with tetrathyridia metacestodes obtained from naturally infected lizards (Anolis carolinensis) from Louisiana. Spermiogenesis in M. lineatus is characterized by the orthogonal growth of a free flagellum, a flagellar rotation, and a proximodistal fusion. The zone of differentiation contains 2 centrioles associated with striated rootlets and a reduced intercentriolar body. The mature spermatozoon of M. lineatus lacks a mitochondrion, and it is characterized by the presence of (1) a single, spiraled, crested body 150 nm thick; (2) a single axoneme of the 9+'1' pattern of trepaxonematan Platyhelminthes; (3) a parallel and reduced row of submembranous cortical microtubules; (4) a spiraled cordon of glycogen granules; and (5) a spiraled nucleus encircling the axoneme. PMID:17626346

  7. Occurrence of Mesocestoides canislagopodis (Rudolphi, 1810) (Krabbe, 1865) in mammals and birds in Iceland and its molecular discrimination within the Mesocestoides species complex.

    PubMed

    Skirnisson, Karl; Jouet, Damien; Ferté, Hubert; Nielsen, Ólafur K

    2016-07-01

    The life cycle of Mesocestoides tapeworms (Cestoda: Cyclophyllidea: Mesocestoididae) requires three hosts. The first intermediate host is unknown but believed to be an arthropod. The second intermediate host is a vertebrate. The primary definitive host is a carnivore mammal, or a bird of prey, that eats the tetrathyridium-infected second intermediate host. One representative of the genus, Mesocestoides canislagopodis, has been reported from Iceland. It is common in the arctic fox (Vulpes lagopus) and has also been detected in domestic dogs (Canis familiaris) and cats (Felis domestica). Recently, scolices of a non-maturing Mesocestoides sp. have also been detected in gyrfalcon (Falco rusticolus) intestines, and tetrathyridia in the body cavity of rock ptarmigan (Lagopus muta). We examined the taxonomic relationship of Mesocestoides from arctic fox, gyrfalcon, and rock ptarmigan using molecular methods, both at the generic level (D1 domain LSU ribosomal DNA) and at the specific level (cytochrome c oxidase subunit I (COI) and 12S mitochondrial DNA). All stages belonged to Mesocestoides canislagopodis. Phylogenetic analysis of the combined 12S-COI at the specific level confirmed that M. canislagopodis forms a distinct clade, well separated from three other recognized representatives of the genus, M. litteratus, M. lineatus, and M. corti/vogae. This is the first molecular description of this species. The rock ptarmigan is a new second intermediate host record, and the gyrfalcon a new primary definitive host record. However, the adult stage seemed not to be able to mature in the gyrfalcon, and successful development is probably restricted to mammalian hosts. PMID:26984208

  8. Inhibition of Tapeworm Thioredoxin and Glutathione Pathways by an Oxadiazole N-Oxide Leads to Reduced Mesocestoides vogae Infection Burden in Mice.

    PubMed

    Pasquet, Vivian; Bisio, Hugo; López, Gloria V; Romanelli-Cedrez, Laura; Bonilla, Mariana; Saldaña, Jenny; Salinas, Gustavo

    2015-01-01

    Parasitic flatworms cause serious infectious diseases that affect humans and livestock in vast regions of the world, yet there are few effective drugs to treat them. Thioredoxin glutathione reductase (TGR) is an essential enzyme for redox homeostasis in flatworm parasites and a promising pharmacological target. We purified to homogeneity and characterized the TGR from the tapeworm Mesocestoides vogae (syn. M. corti). This purification revealed absence of conventional TR and GR. The glutathione reductase activity of the purified TGR exhibits a hysteretic behavior typical of flatworm TGRs. Consistently, M. vogae genome analysis revealed the presence of a selenocysteine-containing TGR and absence of conventional TR and GR. M. vogae thioredoxin and glutathione reductase activities were inhibited by 3,4-bis(phenylsulfonyl)-1,2,5-oxadiazole N2-oxide (VL16E), an oxadiazole N-oxide previously identified as an inhibitor of fluke and tapeworm TGRs. Finally, we show that mice experimentally infected with M. vogae tetrathyridia and treated with either praziquantel, the reference drug for flatworm infections, or VL16E exhibited a 28% reduction of intraperitoneal larvae numbers compared to vehicle treated mice. Our results show that oxadiazole N-oxide is a promising chemotype in vivo and highlights the convenience of M. vogae as a model for rapid assessment of tapeworm infections in vivo. PMID:26132905

  9. Modelling motions within the organ of Corti

    NASA Astrophysics Data System (ADS)

    Ni, Guangjian; Baumgart, Johannes; Elliott, Stephen

    2015-12-01

    Most cochlear models used to describe the basilar membrane vibration along the cochlea are concerned with macromechanics, and often assume that the organ of Corti moves as a single unit, ignoring the individual motion of different components. New experimental technologies provide the opportunity to measure the dynamic behaviour of different components within the organ of Corti, but only for certain types of excitation. It is thus still difficult to directly measure every aspect of cochlear dynamics, particularly for acoustic excitation of the fully active cochlea. The present work studies the dynamic response of a model of the cross-section of the cochlea, at the microscopic level, using the finite element method. The elastic components are modelled with plate elements and the perilymph and endolymph are modelled with inviscid fluid elements. The individual motion of each component within the organ of Corti is calculated with dynamic pressure loading on the basilar membrane and the motions of the experimentally accessible parts are compared with measurements. The reticular lamina moves as a stiff plate, without much bending, and is pivoting around a point close to the region of the inner hair cells, as observed experimentally. The basilar membrane shows a slightly asymmetric mode shape, with maximum displacement occurring between the second-row and the third-row of the outer hair cells. The dynamics responses is also calculated, and compared with experiments, when driven by the outer hair cells. The receptance of the basilar membrane motion and of the deflection of the hair bundles of the outer hair cells is thus obtained, when driven either acoustically or electrically. In this way, the fully active linear response of the basilar membrane to acoustic excitation can be predicted by using a linear superposition of the calculated receptances and a defined gain function for the outer hair cell feedback.

  10. Comparative Analysis of Cystatin Superfamily in Platyhelminths

    PubMed Central

    Guo, Aijiang

    2015-01-01

    The cystatin superfamily is comprised of cysteine proteinase inhibitors and encompasses at least 3 subfamilies: stefins, cystatins and kininogens. In this study, the platyhelminth cystatin superfamily was identified and grouped into stefin and cystatin subfamilies. The conserved domain of stefins (G, QxVxG) was observed in all members of platyhelminth stefins. The three characteristics of cystatins, the cystatin-like domain (G, QxVxG, PW), a signal peptide, and one or two conserved disulfide bonds, were observed in platyhelminths, with the exception of cestodes, which lacked the conserved disulfide bond. However, it is noteworthy that cestode cystatins had two tandem repeated domains, although the second tandem repeated domain did not contain a cystatin-like domain, which has not been previously reported. Tertiary structure analysis of Taenia solium cystatin, one of the cestode cystatins, demonstrated that the N-terminus of T. solium cystatin formed a five turn α-helix, a five stranded β-pleated sheet and a hydrophobic edge, similar to the structure of chicken cystatin. Although no conserved disulfide bond was found in T. solium cystatin, the models of T. solium cystatin and chicken cystatin corresponded at the site of the first disulfide bridge of the chicken cystatin. However, the two models were not similar regarding the location of the second disulfide bridge of chicken cystatin. These results showed that T. solium cystatin and chicken cystatin had similarities and differences, suggesting that the biochemistry of T. solium cystatin could be similar to chicken cystatin in its inhibitory function and that it may have further functional roles. The same results were obtained for other cestode cystatins. Phylogenetic analysis showed that cestode cystatins constituted an independent clade and implied that cestode cystatins should be considered to have formed a new clade during evolution. PMID:25853513

  11. Imaging Organ of Corti Vibration Using Fourier-Domain OCT

    NASA Astrophysics Data System (ADS)

    Choudhury, Niloy; Chen, Fangyi; Fridberger, Anders; Zha, Dingjun; Jacques, Steven L.; Wang, Ruikang K.; Nuttall, Alfred L.

    2011-11-01

    Measuring the sound stimulated vibration from various structures in the organ of Corti is important in understanding how the small vibrations are amplified and detected. In this study we examine the feasibility of using phase-sensitive Fourier domain optical coherence tomography (PSFD-OCT) to measure vibration of the cellular structures of the organ of Corti. PSFD-OCT is a low coherence interferrometry system where the interferrogram is detected as a function of wavelength. The phase of the Fourier transformation of the detected spectra contains path deference (between the sample arm and the reference arm) information of the interferometer. In PSFD-OCT this phase is measured as a function of time and thus any time dependent change in the path difference between the sample arm and the reference arm can be detected. In the experiment, we used an in vitro preparation of the guinea pig cochlea and made a surgical opening at the apical end to access the organ of Corti. By applying tones with different frequencies via the intact middle ear, we recorded the structural vibration inside the organ of Corti. Vibration amplitude and phase of different substructures were mapped on a cross-section view of the organ of Corti. Although the measurements were made at the apical turn of the cochlea, it will be possible to make vibration measurement from various turns of the cochlea. The noise floor of the system was 0.3 nm, calibrated using a piezo stack as a calibrator.

  12. Environmental determinants of the spatial distribution of Mesocestoides spp. and sensitivity of flotation method for the diagnosis of mesocestoidosis.

    PubMed

    Széll, Z; Tolnai, Z; Sréter, T

    2015-09-15

    Mesocestoides spp. are zoonotic cestodes of wild and domesticated carnivores. Although the adult stages are relatively harmless intestinal parasites, the metacestode stages (tetrathyridia) can be responsible for life-threatening peritonitis and pleuritis in several species including dogs, cats, non-human primates and probably man. The aim of the present study was to reveal the spatial distribution pattern of Mesocestoides spp. in the most important final hosts, red foxes (Vulpes vulpes), to analyse the relationship of these patterns with landscape and climate by geographical information systems and to evaluate faecal flotation method for the detection of infection in the final host. Fox carcasses, representing 0.5% of the total fox population were randomly selected out of all the foxes of Hungary. The intestinal tract was examined by sedimentation and counting technique. The sensitivity of the flotation method was evaluated by the testing of the faecal samples of 180 foxes infected with Mesocestoides spp. The prevalence of infection was high in foxes (45.8%; 95% CI=41.0-50.6%), and the parasite was detected in all areas of Hungary. The high prevalence of the parasite in foxes suggests that the infection might also be common in outdoor dogs and cats. Mesocestoides infection could not be detected in any of the foxes by flotation method indicating that the sensitivity of the method is less than 0.6%. Therefore, almost all canine and feline infections remain undetected in the veterinary practice. Based on the statistical analysis, the altitude was the only determinant of the spatial distribution of Mesocestoides spp. indicating that infections in carnivores including dogs and cats can be expected mainly in midland regions (150-750 m above sea level). It might be attributed to the altitude-dependent species richness and abundance of the intermediate and final hosts of the parasite. PMID:26150263

  13. Finite-element model of the active organ of Corti.

    PubMed

    Ni, Guangjian; Elliott, Stephen J; Baumgart, Johannes

    2016-02-01

    The cochlear amplifier that provides our hearing with its extraordinary sensitivity and selectivity is thought to be the result of an active biomechanical process within the sensory auditory organ, the organ of Corti. Although imaging techniques are developing rapidly, it is not currently possible, in a fully active cochlea, to obtain detailed measurements of the motion of individual elements within a cross section of the organ of Corti. This motion is predicted using a two-dimensional finite-element model. The various solid components are modelled using elastic elements, the outer hair cells (OHCs) as piezoelectric elements and the perilymph and endolymph as viscous and nearly incompressible fluid elements. The model is validated by comparison with existing measurements of the motions within the passive organ of Corti, calculated when it is driven either acoustically, by the fluid pressure or electrically, by excitation of the OHCs. The transverse basilar membrane (BM) motion and the shearing motion between the tectorial membrane and the reticular lamina are calculated for these two excitation modes. The fully active response of the BM to acoustic excitation is predicted using a linear superposition of the calculated responses and an assumed frequency response for the OHC feedback. PMID:26888950

  14. Morphological characteristics of Mesocestoides canislagopodis (Krabbe 1865) tetrathyridia found in rock ptarmigan (Lagopus muta) in Iceland.

    PubMed

    Skirnisson, Karl; Sigurðardóttir, Ólöf G; Nielsen, Ólafur K

    2016-08-01

    Necropsies of 1010 rock ptarmigans (Lagopus muta) sampled in autumn 2006-2015 in northeast Iceland revealed Mesocestoides canislagopodis tetrathyridia infections in six birds (0.6 %), two juvenile birds (3 month old), and four adult birds (15 months or older). Four birds had tetrathyridia in the body cavity, one bird in the liver, and one bird both in the body cavity and the liver. There were more tetrathyridia in the body cavity of the two juveniles (c. 50 in each) than in three adults (10-40), possibly indicating a host-age-related tetrathyridia mortality. Approximately, half of tetrathyridia in the body cavity were free or loosely attached to the serosa, the other half were encapsulated in a thin, loose connective tissue stroma, frequently attached to the lungs and the liver. Tetrathyridia in the liver parenchyma incited variably intense inflammation. Tetrathyridia from the juvenile hosts were whitish, heart-shaped, and flattened, with unsegmented bodies with a slightly pointed posterior end. In the adult hosts, tetrathyridia were sometimes almost rectangular-shaped, slightly wider compared to those in the juveniles, but more than twice as long as the younger-aged tetrathyridia. Tetrathyridia infections are most likely acquired during the brief insectivorous feeding phase of ptarmigan chicks, and the tetrathyridia persist throughout the lifespan of the birds. PMID:27117162

  15. A MULTISCALE MODEL OF THE ORGAN OF CORTI

    PubMed Central

    Steele, Charles R.; Boutet de Monvel, Jacques; Puria, Sunil

    2010-01-01

    The organ of Corti is the sensory epithelium in the cochlea of the inner ear. It is modeled as a shell-of-revolution structure with continuous and discrete components. Our recent work has been on the inclusion of the viscous fluid. Measurements from various laboratories provide the opportunity to refocus on the elastic properties. The current detailed model for the organ of Corti is reasonably consistent with diverse measurements. Most components have little stiffness in the propagation direction. However, the isotropic stiffness of the pillar heads is found to offer an explanation for the difference in point load and pressure measurements. The individual rows of inner hair cell stereocilia with tip links and the Hensen stripe are included, since these details are important for the determination of the neural excitation. The results for low frequency show a phase of tip link tension similar to auditory nerve measurements. The nonlinearity of fluid in the small gaps is considered. A result is that as amplitude increases, because of the near contact with the Hensen stripe, the excitation changes polarity, similar to the peak-splitting neural behavior sometimes observed. PMID:20485573

  16. Mitochondrial genome data support the basal position of acoelomorpha and the polyphyly of the platyhelminthes

    SciTech Connect

    Ruiz-Trillo, Inaki; Riutort, Marta; Fourcade, H. Matthew; Baguna, Jaume; Boore, Jeffrey L.

    2004-05-01

    We determined 9.7, 5.2, and 6.8 kb, respectively, of the mitochondrial genomes of the acoel Paratomella rubra, the nemertodermatid Nemertoderma westbladi and the free-living rhabditophoran platyhelminth Microstomum lineare. The identified gene arrangements are unique among metazoans, including each other, sharing no more than one or two single gene boundaries with a few distantly related taxa. Phylogenetic analysis of the amino acid sequences inferred from the sequenced genes confirms that the acoelomorph flatworms (acoels + nemertodermatids) do not belong to the Platyhelminthes, but are, instead, the most basal extant bilaterian group. Therefore, the Platyhelminthes, as traditionally constituted, is a polyphyletic phylum.

  17. The complete mitochondrial genome of Dugesia japonica (Platyhelminthes; order Tricladida).

    PubMed

    Sakai, Masato; Sakaizumi, Mitsuru

    2012-10-01

    We used two sequencing methods, namely long polymerase chain reaction (PCR) and primer walking, to determine the complete mitochondrial DNA (mtDNA) sequence of Dugesia japonica and most of the mtDNA sequence of Dugesia ryukyuensis. The genome of D. japonica contained 36 genes including 12 of the 13 protein-coding genes characteristic of metazoan mitochondrial genomes, two ribosomal RNA genes, and 22 transfer RNA genes. The genome of D. ryukyuensis contained 33 genes, including 12 protein-coding genes, two ribosomal RNA genes, and 19 transfer RNA genes. The gene order of the mitochondrial genome from the Dugesia species showed no clear homology with either the Neodermata or other free-living Rhabditophora. This indicates that the platyhelminths exhibit great variability in mitochondrial gene order. This is the first complete sequence analysis of the mitochondrial genome of a free-living member of Rhabditophora, which will facilitate further studies on the population genetics and genomic evolution of the Platyhelminthes. PMID:23030340

  18. Primary culture and plasmid electroporation of the murine organ of Corti.

    PubMed

    Parker, Mark; Brugeaud, Aurore; Edge, Albert S B

    2010-01-01

    In all mammals, the sensory epithelium for audition is located along the spiraling organ of Corti that resides within the conch shaped cochlea of the inner ear (fig 1). Hair cells in the developing cochlea, which are the mechanosensory cells of the auditory system, are aligned in one row of inner hair cells and three (in the base and mid-turns) to four (in the apical turn) rows of outer hair cells that span the length of the organ of Corti. Hair cells transduce sound-induced mechanical vibrations of the basilar membrane into neural impulses that the brain can interpret. Most cases of sensorineural hearing loss are caused by death or dysfunction of cochlear hair cells. An increasingly essential tool in auditory research is the isolation and in vitro culture of the organ explant. Once isolated, the explants may be utilized in several ways to provide information regarding normative, anomalous, or therapeutic physiology. Gene expression, stereocilia motility, cell and molecular biology, as well as biological approaches for hair cell regeneration are examples of experimental applications of organ of Corti explants. This protocol describes a method for the isolation and culture of the organ of Corti from neonatal mice. The accompanying video includes stepwise directions for the isolation of the temporal bone from mouse pups, and subsequent isolation of the cochlea, spiral ligament, and organ of Corti. Once isolated, the sensory epithelium can be plated and cultured in vitro in its entirety, or as a further dissected micro-isolate that lacks the spiral limbus and spiral ganglion neurons. Using this method, primary explants can be maintained for 7-10 days. As an example of the utility of this procedure, organ of Corti explants will be electroporated with an exogenous DsRed reporter gene. This method provides an improvement over other published methods because it provides reproducible, unambiguous, and stepwise directions for the isolation, microdissection, and primary

  19. Organ of Corti Micromechanics with Local Electrical Stimulation

    NASA Astrophysics Data System (ADS)

    Chen, Fangyi; Zheng, Jiefu; Choudhury, Niloy; Jaques, Steve; Nuttall, Alfred L.

    2009-02-01

    Optical low coherence interferometry is able to both image and measure the vibration of the cellular and non-cellular structures of the organ of Corti in vivo. In this study we applied an electric current to the basal turn from a pair of electrodes, one in scala tympani and the other in scala vestibuli, at the location corresponding to ~17 kHz when interferometry measurements were made. The coherence gate of the interferometer was positioned 1) at the basilar membrane (BM) near the radial location of the outer hair cells (OHCs) (approximately 1/2 the width of the BM) and 2) at the reticular lamina (RL) where the OHCs are located. We confirmed that electrical stimulation with a frequency sweep (12 kHz -25 kHz) caused a mechanical BM displacement with a peak and a traveling wave-like phase delay as we reported previously using laser Doppler velocimetry and reflective beads on the BM. Reflective beads were not used in the current study. The vibration of the RL had little or no phase delay that would characterize a traveling wave. These data suggest a very high compliance system for the electrically activated cellular structure of the organ.

  20. Consequences of Location-Dependent Organ of Corti Micro-Mechanics

    PubMed Central

    Liu, Yanju; Gracewski, Sheryl M.; Nam, Jong-Hoon

    2015-01-01

    The cochlea performs frequency analysis and amplification of sounds. The graded stiffness of the basilar membrane along the cochlear length underlies the frequency-location relationship of the mammalian cochlea. The somatic motility of outer hair cell is central for cochlear amplification. Despite two to three orders of magnitude change in the basilar membrane stiffness, the force capacity of the outer hair cell’s somatic motility, is nearly invariant over the cochlear length. It is puzzling how actuators with a constant force capacity can operate under such a wide stiffness range. We hypothesize that the organ of Corti sets the mechanical conditions so that the outer hair cell’s somatic motility effectively interacts with the media of traveling waves—the basilar membrane and the tectorial membrane. To test this hypothesis, a computational model of the gerbil cochlea was developed that incorporates organ of Corti structural mechanics, cochlear fluid dynamics, and hair cell electro-physiology. The model simulations showed that the micro-mechanical responses of the organ of Corti are different along the cochlear length. For example, the top surface of the organ of Corti vibrated more than the bottom surface at the basal (high frequency) location, but the amplitude ratio was reversed at the apical (low frequency) location. Unlike the basilar membrane stiffness varying by a factor of 1700 along the cochlear length, the stiffness of the organ of Corti complex felt by the outer hair cell remained between 1.5 and 0.4 times the outer hair cell stiffness. The Y-shaped structure in the organ of Corti formed by outer hair cell, Deiters cell and its phalange was the primary determinant of the elastic reactance imposed on the outer hair cells. The stiffness and geometry of the Deiters cell and its phalange affected cochlear amplification differently depending on the location. PMID:26317521

  1. Stimulus-related potassium changes in the organ of Corti of guinea-pig.

    PubMed

    Johnstone, B M; Patuzzi, R; Syka, J; Syková, E

    1989-01-01

    1. Potassium concentration was measured with double-barrelled K+-selective microelectrodes within the organ of Corti in the first turn of the guinea-pig cochlea. 2. Penetration of the electrode from scala tympani through the basilar membrane was accompanied by an increase in K+ resting level from 3.0 mmol/l in perilymph to 3.4 mmol/l in cortilymph (n = 8). K+ resting level was not significantly different in various extracellular regions of the organ of Corti. On penetration of the cuticular plate, the K+ level reached 140 mmol/l simultaneously with the occurrence of a +80 mV endocochlear potential. Impalement of hair cells and supporting cells was accompanied by an increase in K+ level, but intracellular K+ level was not systematically measured. 3. Stimulation with pure tones over the frequency range 500 Hz to 25 kHz produced changes in the K+ level in the organ of Corti. The magnitude of these changes was dependent on stimulus frequency and intensity. At high sound intensities the K+ level in the tunnel of Corti could increase by typically 1 mmol/l, while a maximum increase of 3 mmol/l with respect to the resting level was observed immediately adjacent to inner hair cells. 4. During brief exposures to moderate intensity, pure tone acoustic stimulation (10 s, less than 80 dB SPL (sound pressure level] of frequency 4 kHz or greater the K+ level in the extracellular fluid of the organ of Corti rose monotonically to a steady peak level. On cessation of the stimulus the K+ level fell monotonically with a time constant of about 2 s to a level close to the pre-stimulus level. In some cases this level was slightly above the pre-stimulus level. 5. For brief exposures to moderate intensity sound (10 s, less than 80 dB SPL) the extracellular potential in the organ of Corti became more positive. The amplitude of this sound-evoked change adapted during stimulation to a level approximately one-fifth of its initial value. Upon cessation of the stimulus the potential fell

  2. Cytosine methylation is a conserved epigenetic feature found throughout the phylum Platyhelminthes

    PubMed Central

    2013-01-01

    Background The phylum Platyhelminthes (flatworms) contains an important group of bilaterian organisms responsible for many debilitating and chronic infectious diseases of human and animal populations inhabiting the planet today. In addition to their biomedical and veterinary relevance, some platyhelminths are also frequently used models for understanding tissue regeneration and stem cell biology. Therefore, the molecular (genetic and epigenetic) characteristics that underlie trophic specialism, pathogenicity or developmental maturation are likely to be pivotal in our continued studies of this important metazoan group. Indeed, in contrast to earlier studies that failed to detect evidence of cytosine or adenine methylation in parasitic flatworm taxa, our laboratory has recently defined a critical role for cytosine methylation in Schistosoma mansoni oviposition, egg maturation and ovarian development. Thus, in order to identify whether this epigenetic modification features in other platyhelminth species or is a novelty of S. mansoni, we conducted a study simultaneously surveying for DNA methylation machinery components and DNA methylation marks throughout the phylum using both parasitic and non-parasitic representatives. Results Firstly, using both S. mansoni DNA methyltransferase 2 (SmDNMT2) and methyl-CpG binding domain protein (SmMBD) as query sequences, we illustrate that essential DNA methylation machinery components are well conserved throughout the phylum. Secondly, using both molecular (methylation specific amplification polymorphism, MSAP) and immunological (enzyme-linked immunoabsorbent assay, ELISA) methodologies, we demonstrate that representative species (Echinococcus multilocularis, Protopolystoma xenopodis, Schistosoma haematobium, Schistosoma japonicum, Fasciola hepatica and Polycelis nigra) within all four platyhelminth classes (Cestoda, Monogenea, Trematoda and ‘Turbellaria’) contain methylated cytosines within their genome compartments

  3. Equivalence Relations Between the Cortie and Zürich Sunspot Group Morphological Classifications

    NASA Astrophysics Data System (ADS)

    Carrasco, V. M. S.; Lefèvre, L.; Vaquero, J. M.; Gallego, M. C.

    2015-05-01

    Catalogues of sunspots have been available with useful information about sunspots or sunspot groups for approximately the last 150 years. However, the task of merging these catalogues is not simple. We suggest a method of converting the types of sunspot groups that was proposed by Cortie ( Astrophys. J. 13, 260, 1901) into the well-known Zürich types of sunspot groups. To achieve this, we used the sunspot catalogue of the Valencia University Observatory (from 1920 to 1928) in addition to the descriptions proposed by Cortie. To assess the quality of this conversion scheme, the Zürich type was computed from the Valencia catalogue, and the resulting contribution of each group type was compared to what can be found in other catalogues. The results show that the proposed scheme works well within the errors that are found in the different catalogues.

  4. Harmonic Response of the Organ of Corti: Results for Wave Dispersion

    NASA Astrophysics Data System (ADS)

    Foucaud, Simon; Michon, Guilhem; Morlier, Joseph; Gourinat, Yves

    2011-11-01

    Inner ear is a remarkable multiphysical system and its modelling is a great challenge. The approach used in this paper aims to reproduce physic with a realistic description of the radial cross section of the cochlea. A 2D-section of the organ of Corti is fully described. Wavenumbers and corresponding modes of propagation are calculated taking into account passive structural responses. The study is extended to six cross sections of the organ of Corti and a large frequency bandwidth from 100 Hz to 3 kHz. Dispersion curves reveal the influence of fluid structure interactions with a dispersive behavior at high frequencies. Longitudinal mechanical coupling provides new interacting modes of propagation.

  5. Characterization of the mouse organ of Corti cytoarchitecture using a stick representation

    NASA Astrophysics Data System (ADS)

    Soons, Joris A.; Ricci, Anthony J.; Steele, Charles R.; Puria, Sunil

    2015-02-01

    The supporting cells and hair cells (HCs) in the organ of Corti (OoC) are highly organized. The precise 3D micro-structure is hypothesized to play a critical role in cochlear function. Recently, we combined two techniques to obtain the organ of Corti cytoarchitecture. Two-photon imaging allowed us to perform in situ imaging without subjecting the tissue to other potential distortions, while genetically engineered mTmG mice have a fluorophore embedded in the cell membranes. In this contribution we discuss the parameterization step necessary to compare structures obtained with this technique at different locations and in different specimens. First, the z-axis is chosen perpendicular to the basilar membrane. Subsequently, base and apex of cells are indicated by landmarks. As such, the cells are approximated as a stick representation. This representation is used to calculate the 3D lengths and angles of all imaged cells. Since the OoC is not straight but spiral-shaped, the radial (y) and longitudinal (x) directions differ at each location. Therefore, circular arcs are fitted through the 3 rows of outer HCs to define the local radial (y) and longitudinal (x) direction. Novel in this approach is the 3D data of the cell position in the organ of Corti. Cell diameters and tissue areas cannot be quantified with this stick representation and need to be measured separately.

  6. Characterization of the complete mitochondrial genomes from Polycladida (Platyhelminthes) using next-generation sequencing.

    PubMed

    Aguado, M Teresa; Grande, Cristina; Gerth, Michael; Bleidorn, Christoph; Noreña, Carolina

    2016-01-10

    The complete mitochondrial genomes of three polycladids, the acotylean Hoploplana elisabelloi and the cotyleans Enchiridium sp. and Prosthiostomum siphunculus have been assembled with high coverage from Illumina sequencing data. The mt genomes contain 36 genes including 12 of the 13 protein-coding genes characteristic for metazoan mitochondrial genomes, two ribosomal RNA genes, and 22 transfer RNA genes. Gene annotation, gene order, genetic code, start and stop codons and codon bias have been identified. In comparison with the well investigated parasitic Neodermata, our analysis reveals a great diversity of gene orders within Polycladida and Platyhelminthes in general. By analyzing representative genomes of the main groups of Platyhelminthes we explored the phylogenetic relationships of this group. The phylogenetic analyses strongly supported the monophyly of Polycladida, and based on a small taxon sampling suggest the monophyly of Acotylea and Cotylea. PMID:26325071

  7. Vibration of the organ of Corti within the cochlear apex in mice

    PubMed Central

    Gao, Simon S.; Wang, Rosalie; Raphael, Patrick D.; Moayedi, Yalda; Groves, Andrew K.; Zuo, Jian; Applegate, Brian E.

    2014-01-01

    The tonotopic map of the mammalian cochlea is commonly thought to be determined by the passive mechanical properties of the basilar membrane. The other tissues and cells that make up the organ of Corti also have passive mechanical properties; however, their roles are less well understood. In addition, active forces produced by outer hair cells (OHCs) enhance the vibration of the basilar membrane, termed cochlear amplification. Here, we studied how these biomechanical components interact using optical coherence tomography, which permits vibratory measurements within tissue. We measured not only classical basilar membrane tuning curves, but also vibratory responses from the rest of the organ of Corti within the mouse cochlear apex in vivo. As expected, basilar membrane tuning was sharp in live mice and broad in dead mice. Interestingly, the vibratory response of the region lateral to the OHCs, the “lateral compartment,” demonstrated frequency-dependent phase differences relative to the basilar membrane. This was sharply tuned in both live and dead mice. We then measured basilar membrane and lateral compartment vibration in transgenic mice with targeted alterations in cochlear mechanics. Prestin499/499, Prestin−/−, and TectaC1509G/C1509G mice demonstrated no cochlear amplification but maintained the lateral compartment phase difference. In contrast, SfswapTg/Tg mice maintained cochlear amplification but did not demonstrate the lateral compartment phase difference. These data indicate that the organ of Corti has complex micromechanical vibratory characteristics, with passive, yet sharply tuned, vibratory characteristics associated with the supporting cells. These characteristics may tune OHC force generation to produce the sharp frequency selectivity of mammalian hearing. PMID:24920025

  8. [The scientism of racial theories in O cortiço and Canaã].

    PubMed

    Tamano, Luana Tieko Omena; dos Santos, Poliana; Magalhães, Gildo; Martins, Ana Claudia Aymoré

    2011-01-01

    This analysis of the introduction of racial theories to Brazil and their reception by Brazilian intellectuals in the late nineteenth/early twentieth centuries looks at miscegenation, racism, and whitening policies through the lenses of two novels that bear witness to the era's mentality: O cortiço (1890; A Brazilian tenement, 1976), by Aluísio Azevedo, and Canaã (1902; Canaan, 1920), by Graça Aranha. Through historical and literary analysis, the article examines how fiction has portrayed Brazil and the national dilemma aesthetically. PMID:22012096

  9. Impedance analysis of the organ of corti with magnetically actuated probes.

    PubMed

    Scherer, Marc P; Gummer, Anthony W

    2004-08-01

    An innovative method is presented to measure the mechanical driving point impedance of biological structures up to at least 40 kHz. The technique employs an atomic force cantilever with a ferromagnetic coating and an external magnetic field to apply a calibrated force to the cantilever. Measurement of the resulting cantilever velocity using a laser Doppler vibrometer yields the impedance. A key feature of the method is that it permits measurements for biological tissue in physiological solutions. The method was applied to measure the point impedance of the organ of Corti in situ, to elucidate the biophysical basis of cochlear amplification. The basilar membrane was mechanically clamped at its tympanic surface and the measurements conducted at different radial positions on the reticular lamina. The tectorial membrane was removed. The impedance was described by a generalized Voigt-Kelvin viscoelastic model, in which the stiffness was real-valued and independent of frequency, but the viscosity was complex-valued with positive real part, which was dependent on frequency and negative imaginary part, which was independent of frequency. There was no evidence for an inertial component. The magnitude of the impedance was greatest at the tunnel of Corti, and decreased monotonically in each of the radial directions. In the absence of inertia, the mechanical load on the outer hair cells causes their electromotile displacement responses to be reduced by only 10-fold over the entire range of auditory frequencies. PMID:15298940

  10. Patch clamped responses from outer hair cells in the intact adult organ of Corti.

    PubMed

    Mammano, F; Kros, C J; Ashmore, J F

    1995-09-01

    Outer hair cells (OHCs) from the mammalian cochlea act as both sensory cells and motor cells. We report here whole-cell tight seal recordings of OHC activity in their natural embedding tissue, the intact organ of Corti, using a temporal bone preparation. The mean cell resting potential, -76 +/- 4 mV (n = 19) and input conductance (10 +/- 3 nS at -70 mV) of third turn hair cells were significantly lower than have been found in isolated cells. Two main K+ currents in the cell were identified. One current, activated positive to -100 mV, was reduced by 5 mM BaCl2. The other current, activated above -40 mV, was reduced by 100 microM 4-aminopyridine (4-AP) and by 30 mM tetraethylammonium (TEA). Both of these currents have been also identified in recordings reported from isolated cells. On stepping to different membrane potentials, cells imaged in the organ of Corti changed length by an amount large enough to cause visible distortions in neighbouring cells. By quantifying such distortions we estimate that the forces generated by OHCs can account for the enhanced response to sound required by the cochlear amplifier. PMID:7478927

  11. Evolution and Development of the Tetrapod Auditory System: an Organ of Corti-Centric Perspective

    PubMed Central

    Fritzsch, Bernd; Pan, Ning; Jahan, Israt; Duncan, Jeremy S.; Kopecky, Benjamin J.; Elliott, Karen L.; Kersigo, Jennifer; Yang, Tian

    2013-01-01

    The tetrapod auditory system transmits sound through the outer and middle ear to the organ of Corti or other sound pressure receivers of the inner ear where specialized hair cells translate vibrations of the basilar membrane into electrical potential changes that are conducted by the spiral ganglion neurons to the auditory nuclei. In other systems, notably the vertebrate limb, a detailed connection between the evolutionary variations in adaptive morphology and the underlying alterations in the genetic basis of development has been partially elucidated. In this review, we attempt to correlate evolutionary and partially characterized molecular data into a cohesive perspective of the evolution of the mammalian organ of Corti out of the tetrapod basilar papilla. We propose a stepwise, molecularly partially characterized transformation of the ancestral, vestibular developmental program of the vertebrate ear. This review provides a framework to decipher both discrete steps in development and the evolution of unique functional adaptations of the auditory system. The combined analysis of evolution and development establishes a powerful cross-correlation where conclusions derived from either approach become more meaningful in a larger context not possible through exclusively evolution or development centered perspectives. PMID:23331918

  12. Can Outer Hair Cells Actively Pump Fluid into the Tunnel of Corti?

    NASA Astrophysics Data System (ADS)

    Zagadou, Brissi Franck; Mountain, David C.

    2011-11-01

    Non-classical models of the cochlear traveling wave have been introduced in attempt to capture the unique features of the cochlear amplifier (CA). These models include multiple modes of longitudinal coupling. In one approach, it is hypothesized that two wave modes can add their energies to create amplification such as that desired in the CA. The tunnel of Corti (ToC) was later used to represent the second wave mode for the proposed traveling wave amplifier model, and was incorporated in a multi-compartment cochlea model. The results led to the hypothesis that the CA functions as a fluid pump. However, this hypothesis must be consistent with the anatomical structure of the organ of Corti (OC). The fluid must pass between the outer pillar cells before reaching the ToC, and the ToC fluid and the underlying basilar membrane must constitute an appropriate waveguide. We have analyzed an anatomically based 3D finite element model of the ToC of the gerbil. Our results demonstrate that the OC structure is consistent with the hypothesis.

  13. Displacements of the organ of Corti by gel injections into the cochlear apex

    PubMed Central

    Salt, Alec N.; Brown, Daniel J.; Hartsock, Jared J.; Plontke, Stefan K.

    2009-01-01

    In order to transduce sounds efficiently, the stereocilia of hair cells in the organ of Corti must be positioned optimally. Mechanical displacements, such as pressure differentials across the organ caused by endolymphatic hydrops, may impair sensitivity. Studying this phenomenon has been limited by the technical difficulty of inducing sustained displacements of stereocilia in vivo. We have found that small injections (0.5 to 2 μL) of Healon gel into the cochlear apex of guinea pigs produced sustained changes of endocochlear potential (EP), summating potential (SP) and transducer operating point (OP) in a manner consistent with a mechanically-induced position change of the organ of Corti in the basal turn. Induced changes immediately recovered when injection ceased. In addition, effects of low-frequency bias tones on EP, SP and OP were enhanced during the injection of gel and remained hypersensitive after injection ceased. This is thought to result from the viscous gel mechanically limiting pressure shunting through the helicotrema. Cochlear microphonics measured as frequency was varied showed enhancement below 100 Hz but most notably in the sub-auditory range. Sensitivity to low-frequency biasing was also enhanced in animals with surgically-induced endolymphatic hydrops, suggesting that obstruction of the perilymphatic space by hydrops could contribute to the pathophysiology of this condition. PMID:19217935

  14. Three-Dimensional Imaging of the Mouse Organ of Corti Cytoarchitecture for Mechanical Modeling

    NASA Astrophysics Data System (ADS)

    Puria, Sunil; Hartman, Byron; Kim, Jichul; Oghalai, John S.; Ricci, Anthony J.; Liberman, M. Charles

    2011-11-01

    Cochlear models typically use continuous anatomical descriptions and homogenized parameters based on two-dimensional images for describing the organ of Corti. To produce refined models based more closely on the actual cochlear cytoarchitecture, three-dimensional morphometric parameters of key mechanical structures are required. Towards this goal, we developed and compared three different imaging methods: (1) A fixed cochlear whole-mount preparation using the fluorescent dye Cellmask®, which is a molecule taken up by cell membranes and clearly delineates Deiters' cells, outer hair cells, and the phalangeal process, imaged using confocal microscopy; (2) An in situ fixed preparation with hair cells labeled using anti-prestin and supporting structures labeled using phalloidin, imaged using two-photon microscopy; and (3) A membrane-tomato (mT) mouse with fluorescent proteins expressed in all cell membranes, which enables two-photon imaging of an in situ live preparation with excellent visualization of the organ of Corti. Morphometric parameters including lengths, diameters, and angles, were extracted from 3D cellular surface reconstructions of the resulting images. Preliminary results indicate that the length of the phalangeal processes decreases from the first (inner most) to third (outer most) row of outer hair cells, and that their length also likely varies from base to apex and across species.

  15. Patterns of occurrence of the platyhelminth parasites of the wild bullseye puffer (Sphoeroides annulatus) off Sinaloa, Mexico.

    PubMed

    Fajer-Avila, Emma Josefina; Roque, Ana; Aguilar, Gabriela; Duncan, Neil

    2004-04-01

    This study provides basic information on the occurrence of platyhelminths in the wild bullseye puffer (Sphoeroides annulatus) from Sinaloa, Mexico. Specimens of pufferfish were collected from 2 localities: Teacapan (n = 161) and Mazatlan (n = 66). Six species of platyhelminths were recorded: 2 monogeneans (Diclidophoridae: Heterobothrium ecuadori and Capsalidae: Neobenedenia melleni) and 4 digeneans (Apocreadiidae: Homalometron longisinosum, Lepocreadiidae: Bianium plicitum, Gorgoridae: Phyllodristomum mirandai, and Fellodistomidae: Lintonium vibex). This is the first record of the platyhelminth L. vibex in S. annulatus in the Mexican Pacific. Bianium plicitum was the most abundant species, and H. ecuadori was the most prevalent species. The fish from Teacapan had the higher prevalence of platyhelminths. Teacapan had higher specific richness index, whereas Mazatlan had a higher dominance, 3.098 (Teacapan = 2.38). A relative risk analysis showed that B. plicitum was more likely to be present on fish in water within the temperature range of 21-25 C and from Teacapan compared with fish from the warmer water (26-30 C) or from Mazatlan. Heterobothrium ecuadori was more likely to be present at water temperatures of 23-24.5 C on fish from Teacapan and when other ectoparasites were present. Neobenedenia melleni also was more likely to be present when other parasites were present. PMID:15165072

  16. Nonlinear mechanics of the organ of Corti caused by Deiters cells.

    PubMed

    Böhnke, F; Arnold, W

    1998-10-01

    Though the organ of Corti (OC) has been an object of experimental and theoretical hearing research, open questions remain concerning the processing of acoustic signals by the cochlea where the OC is located. Today there is extensive knowledge about single parts of the organ but a lack of understanding as to how these elements act together. One of the reasons for this is the missing analysis of the mechanics of the OC in three dimensions. In order to fill this gap, we have analyzed a short section (0.06 mm) of the basilar membrane including the OC and evaluated its nonlinear finite element model numerically. The Deiters cells are idealized as thin elastic beams with a comparably low modulus of elasticity of actin. Therefore, they show nonlinear mechanical behavior generating additional frequency components with two-tone stimulation. PMID:9775536

  17. Staining of Platyhelminthes by herbal dyes: An eco-friendly technique for the taxonomist

    PubMed Central

    Kumar, Niranjan; Mehul, Jadav; Das, Bhupamani; Solanki, J. B.

    2015-01-01

    Aim: An environment compatible technique to stain Platyhelminthes, Fasciola gigantica, Gastrothylax crumenifer, Taenia solium, and Moniezia expansa using aqueous and alcoholic extract of sugar beet (Beta vulgaris), China rose (Hibiscus rosa-sinensis), and red rose (Rosa hybrida) were described to minimized the deleterious effects of the synthetic dyes. Materials and Methods: Aqueous/ethanolic extracts of roses were extracted from the flowers while red beet was extracted from the roots. Results: Stained helminthes acquired a comparable level of pigmentation with the distinction of their internal structure in these natural dyes. The flukes (liver and rumen) internal structure, oral and ventral/posterior sucker, cirrus sac, gravid uterus, testes, ovary, and vitallaria were appeared pink color in aqueous and alcoholic extract of either China or red rose and yellow to brown color in sugar beet stain. The interior of the proglottid of T. solium and M. expansa took yellow to brown color with good contrast in sugar beet stain and of pink to pink-red in China and red rose stain. Conclusion: The extract of roses (red rose followed by China rose) followed by red beet possess the potential to replace the conventional stains in the taxonomic study of Platyhelminthes parasites. PMID:27047037

  18. Nuclear genomic signals of the ‘microturbellarian’ roots of platyhelminth evolutionary innovation

    PubMed Central

    Laumer, Christopher E; Hejnol, Andreas; Giribet, Gonzalo

    2015-01-01

    Flatworms number among the most diverse invertebrate phyla and represent the most biomedically significant branch of the major bilaterian clade Spiralia, but to date, deep evolutionary relationships within this group have been studied using only a single locus (the rRNA operon), leaving the origins of many key clades unclear. In this study, using a survey of genomes and transcriptomes representing all free-living flatworm orders, we provide resolution of platyhelminth interrelationships based on hundreds of nuclear protein-coding genes, exploring phylogenetic signal through concatenation as well as recently developed consensus approaches. These analyses robustly support a modern hypothesis of flatworm phylogeny, one which emphasizes the primacy of the often-overlooked ‘microturbellarian’ groups in understanding the major evolutionary transitions within Platyhelminthes: perhaps most notably, we propose a novel scenario for the interrelationships between free-living and vertebrate-parasitic flatworms, providing new opportunities to shed light on the origins and biological consequences of parasitism in these iconic invertebrates. DOI: http://dx.doi.org/10.7554/eLife.05503.001 PMID:25764302

  19. Shape deformation of the organ of Corti associated with length changes of outer hair cell

    NASA Technical Reports Server (NTRS)

    Zimmermann, U.; Fermin, C.

    1996-01-01

    Cochlear outer hair cells (OHC) are commonly assumed to function as mechanical effectors as well as sensory receptors in the organ of Corti (OC) of the inner ear. OHC in vitro and in organ explants exhibit mechanical responses to electrical, chemical or mechanical stimulation which may represent an aspect of their effector process that is expected in vivo. A detailed description, however, of an OHC effector operation in situ is still missing. Specifically, little is known as to how OHC movements influence the geometry of the OC in situ. Previous work has demonstrated that the motility of isolated OHCs in response to electrical stimulation and to K(+)-gluconate is probably under voltage control and causes depolarisation (shortening) and hyperpolarization (elongation). This work was undertaken to investigate if the movements that were observed in isolated OHC, and which are induced by ionic stimulation, could change the geometry of the OC. A synchronized depolarization of OHC was induced in guinea pig cochleae by exposing the entire OC to artificial endolymph (K+). Subsequent morphometry of mid-modiolar sections from these cochleae revealed that the distance between the basilar membrane (BM) and the reticular lamina (RL) had decreased considerably. Furthermore, in the three upper turns OHC had significantly shortened in all rows. The results suggest that OHC can change their length in the organ of Corti (OC) thus deforming the geometry of the OC. The experiments reveal a tonic force generation within the OC that may change the position of RL and/or BM, contribute to damping, modulate the BM-RL-distance and control the operating points of RL and sensory hair bundles. Thus, the results suggest active self-adjustments of cochlear mechanics by slow OHC length changes. Such mechanical adjustments have recently been postulated to correspond to timing elements of animal communication, speech or music.

  20. Notch Signaling and Hes Labeling in the Normal and Drug-Damaged Organ of Corti

    PubMed Central

    Batts, Shelley A.; Shoemaker, Christopher R.; Raphael, Yehoash

    2009-01-01

    During the development of the inner ear, the Notch cell signaling pathway is responsible for the specification of the pro-sensory domain and influences cell fate decisions. It is assumed that Notch signaling ends during maturity and cannot be reinitiated to alter the fate of new or existing cells in the organ of Corti. This is in contrast to non-mammalian species which reinitiate Delta1-Notch1 signaling in response to trauma in the auditory epithelium, resulting in hair cell regeneration through transdifferentiation and/or mitosis. We report immunohistochemical data and Western protein analysis showing that in the aminoglycoside-damaged guinea pig organ of Corti, there is an increase in proteins involved in Notch activation occurring within 24 hours of a chemical hair cell lesion. The signaling response is characterized by the increased presence of Jagged1 ligand in pillar and Deiters cells, Notch1 signal in surviving supporting cell nuclei, and the absence of Jagged2 and Delta-like1. The pro-sensory bHLH protein Atoh1 was absent at all time points following an ototoxic lesion, while the repressor bHLH transcription factors Hes1 and Hes5 were detected in surviving supporting cell nuclei in the former inner and outer hair cell areas, respectively. Notch pathway proteins peaked at 2 weeks, decreased at 1 month, and nearly disappeared by 2 months. These results indicate that the mammalian auditory epithelium retains the ability to regulate Notch signaling and Notch-dependent Hes activity in response to cellular trauma and that the signaling is transient. Additionally, since Hes activity antagonizes the transcription of prosensory Atoh1, the presence of Hes after a lesion may prohibit the occurrence of transdifferentiation in the surviving supporting cells. PMID:19185606

  1. Discovery of Platyhelminth-Specific α/β-Integrin Families and Evidence for Their Role in Reproduction in Schistosoma mansoni

    PubMed Central

    Beckmann, Svenja; Quack, Thomas; Dissous, Colette; Cailliau, Katia; Lang, Gabriele; Grevelding, Christoph G.

    2012-01-01

    In all metazoa, the response of cells to molecular stimuli from their environment represents a fundamental principle of regulatory processes controlling cell growth and differentiation. Among the membrane-linked receptors mediating extracellular communication processes are integrin receptors. Besides managing adhesion to the extracellular matrix or to other cells, they arrange information flow into the cells by activating intracellular signaling pathways often acting synergistically through cooperation with growth factor receptors. Although a wealth of information exists on integrins in different model organisms, there is a big gap of knowledge for platyhelminths. Here we report on the in silico detection and reconstruction of α and β integrins from free-living and parasitic platyhelminths, which according to structural and phylogenetic analyses form specific clades separate from each other and from further metazoan integrins. As representative orthologs of parasitic platyhelminths we have cloned one beta-integrin (Smβ-Int1) and four alpha-integrins (Smα-Int1 - Smα-Int4) from Schistosoma mansoni; they were characterized by molecular and biochemical analyses. Evidence is provided that Smβ-Int1 interacts and co-localizes in the reproductive organs with known schistosome cellular tyrosine kinases (CTKs), of which the Syk kinase SmTK4 appeared to be the strongest interaction partner as shown by yeast two-hybrid analyses and coimmunoprecipitation experiments. By a novel RNAi approach with adult schistosomes in vitro we demonstrate for the first time multinucleated oocytes in treated females, indicating a decisive role Smβ-Int1 during oogenesis as phenotypically analyzed by confocal laser scanning microscopy (CLSM). Our findings provide a first comprehensive overview about platyhelminth integrins, of which the parasite group exhibits unique features allowing a clear distinction from the free-living groups. Furthermore, we shed first lights on the functions of

  2. Cytoarchitecture of the mouse organ of corti from base to apex, determined using in situ two-photon imaging.

    PubMed

    Soons, Joris A M; Ricci, Anthony J; Steele, Charles R; Puria, Sunil

    2015-02-01

    The cells in the organ of Corti are highly organized, with a precise 3D microstructure hypothesized to be important for cochlear function. Here we provide quantitative data on the mouse organ of Corti cytoarchitecture, as determined using a new technique that combines the imaging capabilities of two-photon microscopy with the autofluorescent cell membranes of the genetically modified mTmG mouse. This combination allowed us to perform in situ imaging on freshly excised tissue, thus minimizing any physical distortions to the tissue that extraction from the cochlea and chemical fixation and staining might have caused. 3D image stacks of the organ of Corti were obtained from base to apex in the cochlear duct, from which 3D lengths and relative angles for inner and outer hair cells, Deiters' cells, phalangeal processes, and inner and outer pillars were measured. In addition, intercellular distances, diameters, and stereocilia shapes were obtained. An important feature of this study is the quantitative reporting of the longitudinal tilts of the outer hair cells towards the base of the cochlea, the tilt of phalangeal processes towards the apex, and Deiters' cells that collectively form a Y-shaped building block that is thought to give rise to the lattice-like organization of the organ of Corti. The variations of this Y-shaped element along the cochlear duct and between the rows of outer hair cells are shown with the third row morphologically different from the other rows, and their potential importance for the cochlear amplifier is discussed. PMID:25348579

  3. Optical Coherence Tomography to Measure Sound-Induced Motions Within the Mouse Organ of Corti In Vivo.

    PubMed

    Jawadi, Zina; Applegate, Brian E; Oghalai, John S

    2016-01-01

    The measurement of mechanical vibrations within the living cochlea is critical to understanding the first nonlinear steps in auditory processing, hair cell stimulation, and cochlear amplification. However, it has proven to be a challenging endeavor. This chapter describes how optical coherence tomography (OCT) can be used to measure vibrations within the tissues of the organ of Corti. These experimental measurements can be performed within the unopened cochlea of living mice routinely and reliably. PMID:27259941

  4. In vivo measurement of differential motion inside the organ of Corti using a low coherence interferometer system

    NASA Astrophysics Data System (ADS)

    Chen, Fangyi; Zha, Dingjun; Fridberger, Anders; Zheng, Jiefu; Choudhury, Niloy; Jacques, Steven L.; Wang, Ruikang K.; Nuttall, Alfred L.

    2012-02-01

    The differential motion of the organ of Corti has been expected as a result of the outer hair cell force, believed to be necessary for the cochlear amplifier. In vitro experiments have been performed to demonstrate this motion but the in vivo data was unavailable due to the technical difficulties. Using a specially-designed time-domain optical coherence tomography system, we performed in vivo imaging and vibration measurement at the sensitive base of the guinea pig cochlea. This technique, for the first time, provides in vivo information about the internal vibration of the organ of Corti. At low sound level, when the cochlea is more sensitive, top surface of the organ of Corti, the reticular lamina (RL) showed tuning at a higher frequency than of the bottom surface, basilar membrane (BM) and its vibration amplitude is 2-3 times of that of the BM. Corresponding to the frequency difference, the phase of RL vibration is lead to that of the BM. Both the amplitude gain and the phase lead on RL is level dependent. This suggests that they are related to the cochlear amplification. The amplitude gain at the RL is an enhancement of the BM motion for stimulating the stereocillia. The advance in time of RL vibration can prepare proper timing of stereocillia stimulation for the cochlear amplification.

  5. [The influence of Janicki cercomer theory on the development of platyhelminthes systematics and evolution investigations].

    PubMed

    Pojmańska, Teresa

    2005-01-01

    The aim of this article was to present the development of ideas about the provenience of parasitic helminths and the phylogenetical relationships within this taxon, since the publication of the "cercomer theory" just to nowadays. The following essentials of the Janicki theory are outlined: main differences between free-living Turbellaria and parasitic platyhelminths (ciliated epithelium in Turbellaria versus unciliated surface in the others); universality of the cercomer presence in Monogenea, Digenea and Cestoda; evolutionary changes in the morphology and function of the cercomer; homology of the caudal appendices of all parasitic helminths; the subsequent evolution of parasitic platyhelminthes from the ancestor to Monogena, Digenea and Cestoda; proposition to establish a new common taxon--Cercomerophora--for these three groups. In this background the evolution of evolutionary ideas is reviewed, divided into two periods: up to the eighties of the XX century, and up to date. The first period can be characterised by the criticism of some points of the "cercomer theory" and formulation of some new hypotheses; these are those of Fuhrmann, Bychovsky, Llewellyn, Price and Malmberg, which: questioned the homology of the cercarial tail with the caudal appendices of Monogenea and Cestoda; rejected Digenea from the common group; established the common taxon--Cercomeromorpha--comprising only Monogenea and Cestoda; opposed the idea of radial evolution of three main groups of Platyhelmithes (Turbellaria, Digenea and Cercomeromorpha) to the idea of subsequent evolution presented by Janicki. The differences between these last hypotheses are also underlined, arising mainly from the different ideas on the importance of particular features as the evolutionary indicators of affinities between and within the taxons. As to the hypotheses dealing with the evolution of particular groups of parasitic platyhelminths formulated at the same period, the publications of Freeman and Jarecka

  6. New species of Gieysztoria (Platyhelminthes, Rhabdocoela) from Peruvian Amazon floodplain with description of their stylet ultrastructure.

    PubMed

    Damborenea, Cristina; Brusa, Francisco; Noreña, Carolina

    2005-12-01

    The free-living Platyhelminthes of the Amazon basin are poorly known. Presently only four turbellarian species have been mentioned from the Amazon river, a fact that confirms the lack of information on this kind of faunas in this huge basin. Three new species of Gieysztoria from Amazonian floodplain in Peru are described herein: G. chiqchi n. sp., G. kasasapa n. sp. and G. sasa n. sp. The samples were taken in the Pacaya-Samiria National Reserve (Peru) during September 2002. Besides the usual description of the stylet based on whole mounted specimens, we provide a complementary description using SEM, which allowed differentiation of the new species within the currently yet imperfect picture of the Amazonian turbellarian fauna. Although further research is desired, current findings are suggestive of high diversity of free-living Turbellaria in the surveyed region. PMID:16462104

  7. Cellular glutathione content in the organ of Corti and its role during ototoxicity

    PubMed Central

    Majumder, Paromita; Duchen, Michael R.; Gale, Jonathan E.

    2015-01-01

    Glutathione (GSH) is the major scavenger of reactive oxygen species (ROS) inside cells. We used live confocal imaging in order to clarify the role of GSH in the biology of the organ of Corti, the sensory epithelium of the cochlea, before, during and after the onset of hearing and in ~1 year old mice. GSH content was measured using monochlorobimane (MCB), a non-fluorescent cell permeant bimane that reacts with GSH, forming a fluorescent adduct through a reaction catalyzed by glutathione-S-transferase. GSH content increased significantly in inner hair cells during maturation in young adult animals, whereas there was no significant change in the outer hair cells. However, the GSH content in inner hair cells was significantly reduced in ~1 year old mice. The GSH content of supporting cells was comparatively stable over these ages. To test whether the GSH content played a significant protective role during ototoxicity, GSH synthesis was inhibited by buthionine sulfoximine (BSO) in organotypic cochlear explant cultures from immature mice. BSO treatment alone, which reduced GSH by 65 and 85% in inner hair cells and outer hair cells respectively, did not cause any significant cell death. Surprisingly, GSH depletion had no significant effect on hair cell survival even during exposure to the ototoxic aminoglycoside neomycin. These data suggest that the involvement of ROS during aminoglycoside-induced hair cell death is less clear than previously thought and requires further investigation. PMID:25972783

  8. Phase of neural excitation relative to basilar membrane motion in the organ of Corti: Theoretical considerations

    NASA Astrophysics Data System (ADS)

    Andoh, Masayoshi; Nakajima, Chihiro; Wada, Hiroshi

    2005-09-01

    Although the auditory transduction process is dependent on neural excitation of the auditory nerve in relation to motion of the basilar membrane (BM) in the organ of Corti (OC), specifics of this process are unclear. In this study, therefore, an attempt was made to estimate the phase of the neural excitation relative to the BM motion using a finite-element model of the OC at the basal turn of the gerbil, including the fluid-structure interaction with the lymph fluid. It was found that neural excitation occurs when the BM exhibits a maximum velocity toward the scala vestibuli at 10 Hz and shows a phase delay relative to the BM motion with increasing frequency up to 800 Hz. It then shows a phase advance until the frequency reaches 2 kHz. From 2 kHz, neural excitation again shows a phase delay with increasing frequency. From 800 Hz up to 2 kHz, the phase advances because the dominant force exerted on the hair bundle shifts from a velocity-dependent Couette flow-induced force to a displacement-dependent force induced by the pressure difference. The phase delay that occurs from 2 kHz is caused by the resonance process of the hair bundle of the IHC.

  9. Ultrastructure of the Odontocete organ of Corti: scanning and transmission electron microscopy.

    PubMed

    Morell, Maria; Lenoir, Marc; Shadwick, Robert E; Jauniaux, Thierry; Dabin, Willy; Begeman, Lineke; Ferreira, Marisa; Maestre, Iranzu; Degollada, Eduard; Hernandez-Milian, Gema; Cazevieille, Chantal; Fortuño, José-Manuel; Vogl, Wayne; Puel, Jean-Luc; André, Michel

    2015-02-15

    The morphological study of the Odontocete organ of Corti, together with possible alterations associated with damage from sound exposure, represents a key conservation approach to assess the effects of acoustic pollution on marine ecosystems. By collaborating with stranding networks from several European countries, 150 ears from 13 species of Odontocetes were collected and analyzed by scanning (SEM) and transmission (TEM) electron microscopy. Based on our analyses, we first describe and compare Odontocete cochlear structures and then propose a diagnostic method to identify inner ear alterations in stranded individuals. The two species analyzed by TEM (Phocoena phocoena and Stenella coeruleoalba) showed morphological characteristics in the lower basal turn of high-frequency hearing species. Among other striking features, outer hair cell bodies were extremely small and were strongly attached to Deiters cells. Such morphological characteristics, shared with horseshoe bats, suggest that there has been convergent evolution of sound reception mechanisms among echolocating species. Despite possible autolytic artifacts due to technical and experimental constraints, the SEM analysis allowed us to detect the presence of scarring processes resulting from the disappearance of outer hair cells from the epithelium. In addition, in contrast to the rapid decomposition process of the sensory epithelium after death (especially of the inner hair cells), the tectorial membrane appeared to be more resistant to postmortem autolysis effects. Analysis of the stereocilia imprint pattern at the undersurface of the tectorial membrane may provide a way to detect possible ultrastructural alterations of the hair cell stereocilia by mirroring them on the tectorial membrane. PMID:25269663

  10. Characterizing Wave Propagation in the Organ of Corti with Stroboscopic Imaging

    NASA Astrophysics Data System (ADS)

    Zosuls, Aleks; Rupprecht, Laura C.; Mountain, David C.

    2011-11-01

    Here we present the results from a new high-frequency mechanical stimulation system that was designed to provide more precise local excitation and motion sensing of the organ of Corti (OC/BM complex). It is based on mechanical tissue excitation via a small vibrating probe and measurement using stroboscopic video microscopy. The system is currently capable of measuring sub-micrometer motion at frequencies from DC to 60 kHz. Measurements were performed on excised Mongolian gerbil (Meriones unguiculatus) cochleae. The underside of the BM was mechanically stimulated in the direction normal to the membrane with a 20 μm diameter glass probe. Data was collected at multiple focal planes from the BM to the tectorial membrane in order to capture motion for cellular and extracellular structures. For this study, inner hair cell hair bundles and basilar membrane collagen fiber bundle regions of interest were selected and displacements quantified using a cross-correlation technique. Displacement magnitude and phase was measured as a function of distance from the probe and a function of stimulus frequency. At certain frequencies both magnitudes and phases decreased with distance from the probe in a manner that suggests that both direct longitudinal coupling and wave propagation were contributing to the responses.

  11. Deriving stereocilia displacement from the impedance of the organ of Corti

    NASA Astrophysics Data System (ADS)

    Altoè, Alessandro; Pulkki, Ville

    2015-12-01

    The response of an inner hair cell (IHC) to a sound stimulus varies in terms of phase and harmonic content depending nonlinearly on the stimulus level. This dependency can be explained by the two factor cancellation hypothesis: two excitatory components of the opposite sign, C1 and C2, regulate the IHC receptor potential. However, it is yet unknown whether C1 and C2 represent the contribution of different stereocilia rows to the transduction of a single IHC, or whether they represent different mechanical contributions to the displacement of a single stereocilia bundle. There are also diverse theories about the physical origin of the two components. This work presents a computational model of IHCs functionality having clear physical origins for C1 and C2. In the present model C1 represents the transduction component associated with the coupling between the stereocilia and the basilar membrane (BM), while C2 represents the transduction component associated with the coupling between the stereocilia and the outer hair cells (OHCs). C1 and C2 are derived from the nonlinear cochlear model by Verhulst et al. (2012). In particular, C1 is derived from the BM velocity vector and C2 is derived from the term representing the action of the organ of Corti (OC) on BM motion. The present model is capable to simulate the dynamic response of IHCs and to emulate the dependency of the phase and harmonic content of IHCs response, being in good agreement with animal data. Furthermore, this work introduces a simple physical interpretation of C2 to phenomenological models of two-factor cancellation.

  12. Effect of LLLT on the level of ATP and ROS from organ of corti cells

    NASA Astrophysics Data System (ADS)

    Rhee, ChungKu; Chang, So-Young; Ahn, Jin-Chul; Suh, Myung-Whan; Jung, Jae Yun

    2014-03-01

    It is well established that ototoxic antibiotics and acoustic trauma can damage cochlear hair cells and cause hearing loss. Previous studies using transcanal LLLT (Low level laser therapy) showed that LLLT can promote recovery of hearing thresholds and cochlear hair cells. However, its mechanism has not been studied. Aim: The aim of this study is to investigate the mechanism of hearing recovery from gentamicin induced ototoxic hearing loss by LLLT. Methods: HEI- OC1 (House ear institute organ of Corti) cells were cultured for 18 hours and ototoxicity was induced by gentamicin (GM) treatment to the cells. Cultured cells were divided into 6 groups, No treatment control, LLLT only, GM 6.6 mM and GM 13.1 mM, GM 6.6 mM+LLLT and GM 13.1 mM+LLLT cells. LD laser 808 nm, 15 mW, was irradiated to the cultured cells for 15 min, at 4 hours after GM treatment to the cells. ATP was assayed using the ATP assay Kit. ROS was measured using confocal microscope after application of H2DCFDA dye. Results: ATP was decreased in GM 13.1 mM cells and increased in LLLT only cells and GM 13.1 mM+LLLT cells compared to control and 13.1 mM cells. ROS was increased in GM 6.6 mM and GM 13.1 mM cells, and decreased in GM 6.6 mM+LLLT and GM 13.1 mM+LLLT cells compared to GM 6.6 and 13.1 mM cells immediately after laser irradiation. Conclusion: This study demonstrated that LLLT on GM treated HEI-OC1 cells increased ATP and decreased ROS that may contribute to the recovery of hearing.

  13. Near field fluid coupling between internal motion of the organ of Corti and the basilar membrane

    NASA Astrophysics Data System (ADS)

    Elliott, Stephen J.; Ni, Guangjian

    2015-12-01

    The pressure distribution in each of the fluid chambers of the cochlea can be decomposed into a 1D, or plane wave, component and a near field component, which decays rapidly away from the excitation point. The transverse motion of the basilar membrane, BM, for example, generates both a 1D pressure field, which couples into the slow wave, and a local near field pressure, proportional to the BM acceleration, that generates an added mass on the BM due to the fluid motion. When the organ of Corti, OC, undergoes internal motion, due for example to outer hair cell activity, this motion will not itself generate any 1D pressure if the OC is incompressible and the BM is constrained not to move volumetrically, and so will not directly couple into the slow wave. This motion will, however, generate a near field pressure, proportional to the OC acceleration, which will act on the OC and thus increases its effective mass. The near field pressure due to this OC motion will also act on the BM, generating a force on the BM proportional to the acceleration of the OC, and thus create a "coupling mass" effect. By reciprocity, this coupling mass is the same as that acting on the OC due to the motion of the BM. This near field fluid coupling is initially observed in a finite element model of a slice of the cochlea. These simulations suggest a simple analytical formulation for the fluid coupling, using higher order beam modes across the width of the cochlear partition. It is well known that the added mass due to the near field pressure dominates the overall mass of the BM, and thus significantly affects the micromechanical dynamics. This work not only quantifies the added mass of the OC due its own motion in the fluid, and shows that this is important, but also demonstrates that the coupling mass effect between the BM and OC significantly affects the dynamics of simple micromechanical models.

  14. Near field fluid coupling between internal motion of the organ of Corti and the basilar membrane

    SciTech Connect

    Elliott, Stephen J.; Ni, Guangjian

    2015-12-31

    The pressure distribution in each of the fluid chambers of the cochlea can be decomposed into a 1D, or plane wave, component and a near field component, which decays rapidly away from the excitation point. The transverse motion of the basilar membrane, BM, for example, generates both a 1D pressure field, which couples into the slow wave, and a local near field pressure, proportional to the BM acceleration, that generates an added mass on the BM due to the fluid motion. When the organ of Corti, OC, undergoes internal motion, due for example to outer hair cell activity, this motion will not itself generate any 1D pressure if the OC is incompressible and the BM is constrained not to move volumetrically, and so will not directly couple into the slow wave. This motion will, however, generate a near field pressure, proportional to the OC acceleration, which will act on the OC and thus increases its effective mass. The near field pressure due to this OC motion will also act on the BM, generating a force on the BM proportional to the acceleration of the OC, and thus create a “coupling mass” effect. By reciprocity, this coupling mass is the same as that acting on the OC due to the motion of the BM. This near field fluid coupling is initially observed in a finite element model of a slice of the cochlea. These simulations suggest a simple analytical formulation for the fluid coupling, using higher order beam modes across the width of the cochlear partition. It is well known that the added mass due to the near field pressure dominates the overall mass of the BM, and thus significantly affects the micromechanical dynamics. This work not only quantifies the added mass of the OC due its own motion in the fluid, and shows that this is important, but also demonstrates that the coupling mass effect between the BM and OC significantly affects the dynamics of simple micromechanical models.

  15. Organ of Corti explants direct tonotopically graded morphology of spiral ganglion neurons in vitro.

    PubMed

    Smith, Felicia L; Davis, Robin L

    2016-08-01

    The spiral ganglion is a compelling model system to examine how morphological form contributes to sensory function. While the ganglion is composed mainly of a single class of type I neurons that make simple one-to-one connections with inner hair cell sensory receptors, it has an elaborate overall morphological design. Specific features, such as soma size and axon outgrowth, are graded along the spiral contour of the cochlea. To begin to understand the interplay between different regulators of neuronal morphology, we cocultured neuron explants with peripheral target tissues removed from distinct cochlear locations. Interestingly, these "hair cell microisolates" were capable of both increasing and decreasing neuronal somata size, without adversely affecting survival. Moreover, axon characteristics elaborated de novo by the primary afferents in culture were systematically regulated by the sensory endorgan. Apparent peripheral nervous system (PNS)-like and central nervous system (CNS)-like axonal profiles were established in our cocultures allowing an analysis of putative PNS/CNS axon length ratios. As predicted from the in vivo organization, PNS-like axon bundles elaborated by apical cocultures were longer than their basal counterparts and this phenotype was methodically altered when neuron explants were cocultured with microisolates from disparate cochlear regions. Thus, location-dependent signals within the organ of Corti may set the "address" of neurons within the spiral ganglion, allowing them to elaborate the appropriate tonotopically associated morphological features in order to carry out their signaling function. J. Comp. Neurol. 524:2182-2207, 2016. © 2015 Wiley Periodicals, Inc. PMID:26663318

  16. Whole-Cell Patch-Clamp Recording of Mouse and Rat Inner Hair Cells in the Intact Organ of Corti.

    PubMed

    Goutman, Juan D; Pyott, Sonja J

    2016-01-01

    Whole-cell patch clamping is a widely applied method to record currents across the entire membrane of a cell. This protocol describes application of this method to record currents from the sensory inner hair cells in the intact auditory sensory epithelium, the organ of Corti, isolated from rats or mice. This protocol particularly outlines the basic equipment required, provides instructions for the preparation of solutions and small equipment items, and methodology for recording voltage-activated and evoked synaptic currents from the inner hair cells. PMID:27259943

  17. Diseases of cultured marine fishes caused by Platyhelminthes (Monogenea, Digenea, Cestoda).

    PubMed

    Ogawa, K

    2015-01-01

    Mariculture is a rapidly developing industrial sector. Generally, fish are maintained in net cages with high density. Cage culture systems allow uncontrolled flow of sea water containing potentially infectious stages of fish parasites. In such culture conditions, prevention of such parasitic infections is difficult for parasites with life cycles that complete within culture sites, among which monogeneans and blood flukes are the most important platyhelminthes. Intense monogenean infections induce respiratory and osmo-regulatory dysfunctions. A variety of control measures have been developed, including freshwater bath treatment and chemotherapy. The potential to control monogenean infections through selective breeding, modified culture techniques to avoid infection, and general fish health management are discussed. It should be noted that mariculture conditions have provided some host-specific monogeneans with a chance to expand their host ranges. Blood flukes sometimes induce mass mortality among farmed fish. In-feed administration of praziquantel is the best solution to treat infected fish. Some cases are described that show how international trade in marine fish has resulted in the spread of hitherto unknown parasites into indigenous farmed and wild fish. PMID:24998438

  18. Comparative study of adaptive radiations with an example using parasitic flatworms (Platyhelminthes): Cercomeria

    SciTech Connect

    Brooks, D.R.; McLennan, D.A. )

    1993-11-01

    Studies of adaptive radiations require robust phylogenies, estimates of species numbers for monophyletic groups within clades, assessments of the adaptive value of putative key innovations, and estimates of the frequency of speciation modes. Four criteria are necessary to identify an adaptive radiation within the parasitic platyhelminths: (1) a group contains significantly more species than its sister group, (2) species richness is apomorphic, (3) apomorphic traits enhance the potential for adaptively driven modes of speciation (sympatric speciation and speciation by peripheral isolation via host switching), and (4) the frequency of adaptively driven speciation modes is high within the group when compared with data from free-living groups. Only the species-rich Monogenea fulfill all four criteria. The Digenea and Eucestoda also are more species rich than their sister groups, their species richness is derived, and they possess unique characters that increase the potential for host switching to occur. However, because there is not enough information to determine whether the frequency of adaptive modes of speciation is high for those groups, we cannot yet assert that their radiations have been adaptive. 102 refs., 3 figs., 1 tab.

  19. Problematic barcoding in flatworms: A case-study on monogeneans and rhabdocoels (Platyhelminthes)

    PubMed Central

    Vanhove, Maarten P. M.; Tessens, Bart; Schoelinck, Charlotte; Jondelius, Ulf; Littlewood, D. Tim J.; Artois, Tom; Huyse, Tine

    2013-01-01

    Abstract Some taxonomic groups are less amenable to mitochondrial DNA barcoding than others. Due to the paucity of molecular information of understudied groups and the huge molecular diversity within flatworms, primer design has been hampered. Indeed, all attempts to develop universal flatworm-specific COI markers have failed so far. We demonstrate how high molecular variability and contamination problems limit the possibilities for barcoding using standard COI-based protocols in flatworms. As a consequence, molecular identification methods often rely on other widely applicable markers. In the case of Monogenea, a very diverse group of platyhelminth parasites, and Rhabdocoela, representing one-fourth of all free-living flatworm taxa, this has led to a relatively high availability of nuclear ITS and 18S/28S rDNA sequences on GenBank. In a comparison of the effectiveness in species assignment we conclude that mitochondrial and nuclear ribosomal markers perform equally well. In case intraspecific information is needed, rDNA sequences can guide the selection of the appropriate (i.e. taxon-specific) COI primers if available. PMID:24453567

  20. The power of regeneration and the stem-cell kingdom: freshwater planarians (Platyhelminthes).

    PubMed

    Saló, Emili

    2006-05-01

    The great powers of regeneration shown by freshwater planarians, capable of regenerating a complete organism from any tiny body fragment, have attracted the interest of scientists throughout history. In 1814, Dalyell concluded that planarians could "almost be called immortal under the edge of the knife". Equally impressive is the developmental plasticity of these platyhelminthes, including continuous growth and fission (asexual reproduction) in well-fed organisms, and shrinkage (degrowth) during prolonged starvation. The source of their morphological plasticity and regenerative capability is a stable population of totipotent stem cells--"neoblasts"; this is the only cell type in the adult that has mitotic activity and differentiates into all cell types. This cellular feature is unique to planarians in the Bilateria clade. Over the last fifteen years, molecular studies have begun to reveal the role of developmental genes in regeneration, although it would be premature to propose a molecular model for planarian regeneration. Genomic and proteomic data are essential in answering some of the fundamental questions concerning this remarkable morphological plasticity. Such information should also pave the way to understanding the genetic pathways associated with metazoan somatic stem-cell regulation and pattern formation. PMID:16615086

  1. Inner ear development: Building a spiral ganglion and an organ of Corti out of unspecified ectoderm

    PubMed Central

    Fritzsch, Bernd; Pan, Ning; Jahan, Israt; Elliott, Karen L.

    2014-01-01

    The mammalian inner ear develops from a placodal thickening into a complex labyrinth of ducts with five sensory organs specialized to detect position and movement in space. In addition, the mammalian ear develops a spiraled cochlear duct containing the auditory organ, the organ of Corti (OC), specialized to translate sound into hearing. Developing the OC out of a uniform sheet of ectoderm requires an unparalleled precision in topological developmental engineering of four different general cell types, sensory neurons, hair cells, supporting cells, and general otic epithelium, into a mosaic of ten distinctly recognizable cell types in and around the OC, each with a unique distribution. In addition, the OC receives a unique innervation by ear-derived spiral ganglion afferents and brainstem-derived motor neurons as efferents, and requires neural crest-derived Schwann cells to form myelin and neural crest-derived cells to induce the stria vascularis. To achieve this transformation of a sheet of cells into a complicated interdigitating set of cells necessitates the orchestrated expression of multiple transcription factors that enable the cellular transformation from ectoderm into neurosensory cells forming the spiral ganglion neurons (SGN) while simultaneously transforming the flat epithelium into a tube, the cochlear duct housing the OC. In addition to the cellular and conformational changes to make the cochlear duct with the OC, additional changes in the surrounding periotic mesenchyme form passageways for sound to stimulate the OC. This article reviews molecular developmental data generated predominantly in mice. The available data are ordered into a plausible scenario that integrates the well described expression changes of transcription factors and their actions revealed in mouse mutants for formation of SGNs and OC in the right position and orientation with the right kind of innervation. Understanding the molecular basis of these developmental changes leading to

  2. Elucidating the phylogenetic position of Gnathostomulida and first mitochondrial genomes of Gnathostomulida, Gastrotricha and Polycladida (Platyhelminthes).

    PubMed

    Golombek, Anja; Tobergte, Sarah; Struck, Torsten H

    2015-05-01

    Gnathostomulida is a taxon of small marine worms, which exclusively inhabit the interstitium. The evolution of Gnathostomulida has been discussed for decades. Originally regarded as primitive animals with affinities to flatworms, the phylogenetic position of Gnathostomulida has been debated. Given the lack of an anus a close relationship to Platyhelminthes has been maintained (i.e., Plathelminthomorpha hypothesis). Alternative hypotheses proposed Gnathostomulida as being close to Gastrotricha due to the presence of a monociliary epidermis (i.e., Monokonta/Neotrichozoa hypothesis) or to Syndermata based on the complicated jaw apparatus (i.e., Gnathifera hypothesis). Molecular analyses using only few genes were inconclusive. Recent phylogenomic studies brought some progress by placing Gnathostomulida as sister to Syndermata, but support for this relationship was low and depended on the analytical strategy. Herein we present the first data of complete or nearly complete mitochondrial genomes for two gnathostomulids (Gnathostomula paradoxa &G. armata), one gastrotrich (Lepidodermella squamata) and one polyclad flatworm (Stylochoplana maculata) to address the uncertain phylogenetic affinity of Gnathostomulida. Our analyses found Gnathostomulida as sister to Syndermata (Gnathifera hypothesis). Thorough sensitivity analyses addressing taxon instability, branch length heterogeneity (also known as long branch attraction) and base composition heterogeneity showed that the position of Gnathostomulida is consistent across the different analyses and, hence, independent of potential misleading biases. Moreover, by ameliorating these different biases nodal support values could be increased to maximum values. Thus, our data support the hypothesis that the different jaw apparatuses of Syndermata and Gnathostomulida are indeed homologous structures as proposed by the Gnathifera hypothesis. PMID:25796325

  3. Venus Kinase Receptors Control Reproduction in the Platyhelminth Parasite Schistosoma mansoni

    PubMed Central

    Cailliau, Katia; Morel, Marion; Hahnel, Steffen; Leutner, Silke; Beckmann, Svenja; Grevelding, Christoph G.; Dissous, Colette

    2014-01-01

    The Venus Kinase Receptor (VKR) is a single transmembrane molecule composed of an intracellular tyrosine kinase domain close to that of insulin receptor and an extracellular Venus Flytrap (VFT) structure similar to the ligand binding domain of many class C G Protein Coupled Receptors. This receptor tyrosine kinase (RTK) was first discovered in the platyhelminth parasite Schistosoma mansoni, then in a large variety of invertebrates. A single vkr gene is found in most genomes, except in S. mansoni in which two genes Smvkr1 and Smvkr2 exist. VKRs form a unique family of RTKs present only in invertebrates and their biological functions are still to be discovered. In this work, we show that SmVKRs are expressed in the reproductive organs of S. mansoni, particularly in the ovaries of female worms. By transcriptional analyses evidence was obtained that both SmVKRs fulfill different roles during oocyte maturation. Suppression of Smvkr expression by RNA interference induced spectacular morphological changes in female worms with a strong disorganization of the ovary, which was dominated by the presence of primary oocytes, and a defect of egg formation. Following expression in Xenopus oocytes, SmVKR1 and SmVKR2 receptors were shown to be activated by distinct ligands which are L-Arginine and calcium ions, respectively. Signalling analysis in Xenopus oocytes revealed the capacity of SmVKRs to activate the PI3K/Akt/p70S6K and Erk MAPK pathways involved in cellular growth and proliferation. Additionally, SmVKR1 induced phosphorylation of JNK (c-Jun N-terminal kinase). Activation of JNK by SmVKR1 was supported by the results of yeast two-hybrid experiments identifying several components of the JNK pathway as specific interacting partners of SmVKR1. In conclusion, these results demonstrate the functions of SmVKR in gametogenesis, and particularly in oogenesis and egg formation. By eliciting signalling pathways potentially involved in oocyte proliferation, growth and migration

  4. New Acotylea (Polycladida, Platyhelminthes) from the east coast of the North Atlantic Ocean with special mention of the Iberian littoral.

    PubMed

    Noreña, Carolina; Rodríguez, Jorge; Pérez, Jacinto; Almon, Bruno

    2015-01-01

    Polyclad species diversity, although generally well known for European North Atlantic waters, is nearly unknown for the Iberian Peninsula. The "Ría de Arousa", located on the Atlantic coast of Galicia (Spain), is a place where many positive biological factors for species biodiversity converge. Therefore, it is an ideal location to study polyclad diversity. This research, which describes new records and new species, contributes to the knowledge of the distribution of Polycladida (Platyhelminthes), particularly of the suborder Acotylea, in the Atlantic waters of the Iberian Peninsula. The new records include the re-descriptions of Cryptocelis compacta Lang, 1884, Stylochus neapolitanus (Delle Chiaje, 1841-1844) and Discocelis tigrina (Blanchard, 1847), while the two newly described species are Hoploplana elisabelloi n. sp. and Armatoplana celta n. sp. PMID:26624472

  5. Immunoenzymatic visualization of tetrodotoxin (TTX) in Cephalothrix species (Nemertea: Anopla: Palaeonemertea: Cephalotrichidae) and Planocera reticulata (Platyhelminthes: Turbellaria: Polycladida: Planoceridae).

    PubMed

    Tanu, Mohosena Begum; Mahmud, Yahia; Arakawa, Osamu; Takatani, Tomohiro; Kajihara, Hiroshi; Kawatsu, Kentaro; Hamano, Yonekazu; Asakawa, Manabu; Miyazawa, Keisuke; Noguchi, Tamao

    2004-10-01

    Tetrodotoxin (TTX) was localized as brown color in different tissues of an undescribed species of the nemertean genus Cephalothrix (phylum Nemertea) and a turbellarian Planocera reticulata (phylum Platyhelminthes) on light microscopy by means of a monoclonal anti-TTX antibody. In the Cephalothrix sp., TTX was recognized in the vesicles apically arranged in the bacillary cells in the epidermis, basal lamina, the granular cells in the proboscis epithelium, rhynchocoel epithelium, and the vesicles in the basal portion of the intestinal wall near the blood vessels and rhynchocoel. The excretory system and the ovum also showed positive reaction of TTX antigen-antibody. On the other hand, the hermaphrodite flatworm P. reticulata exhibited TTX antigen-antibody complex only in their ovum. To our knowledge, this is the first experimental effort on micro-distribution of TTX in invertebrates. PMID:15450926

  6. Supervillin Is a Component of the Hair Cell’s Cuticular Plate and the Head Plates of Organ of Corti Supporting Cells

    PubMed Central

    Pollock, Lana M.; Gupta, Nilay; Chen, Xi; Luna, Elizabeth J.; McDermott, Brian M.

    2016-01-01

    The organ of Corti has evolved a panoply of cells with extraordinary morphological specializations to harness, direct, and transduce mechanical energy into electrical signals. Among the cells with prominent apical specializations are hair cells and nearby supporting cells. At the apical surface of each hair cell is a mechanosensitive hair bundle of filamentous actin (F-actin)-based stereocilia, which insert rootlets into the F-actin meshwork of the underlying cuticular plate, a rigid organelle considered to hold the stereocilia in place. Little is known about the protein composition and development of the cuticular plate or the apicolateral specializations of organ of Corti supporting cells. We show that supervillin, an F-actin cross-linking protein, localizes to cuticular plates in hair cells of the mouse cochlea and vestibule and zebrafish sensory epithelia. Moreover, supervillin localizes near the apicolateral margins within the head plates of Deiters’ cells and outer pillar cells, and proximal to the apicolateral margins of inner phalangeal cells, adjacent to the junctions with neighboring hair cells. Overall, supervillin localization suggests this protein may shape the surface structure of the organ of Corti. PMID:27415442

  7. Biology and pathobiology of lipid droplets and their potential role in the protection of the organ of Corti.

    PubMed

    Urrutia, Raul A; Kalinec, Federico

    2015-12-01

    The current review article seeks to extend our understanding on the role of lipid droplets within the organ of Corti. In addition to presenting an overview of the current information about the origin, structure and function of lipid droplets we draw inferences from the collective body of knowledge about this cellular organelle to build a conceptual framework to better understanding their role in auditory function. This conceptual model considers that lipid droplets play a significant role in the synthesis, storage, and release of lipids and proteins for energetic use and/or modulating cell signaling pathways. We describe the role and mechanism by which LD play a role in human diseases, and we also review emerging data from our laboratory revealing the potential role of lipid droplets from Hensen cells in the auditory organ. We suggest that lipid droplets might help to develop rapidly and efficiently the resolution phase of inflammatory responses in the mammalian cochlea, preventing inflammatory damage of the delicate inner ear structures and, consequently, sensorineural hearing loss. PMID:25987503

  8. The molecular basis of making spiral ganglion neurons and connecting them to hair cells of the organ of Corti

    PubMed Central

    Yang, Tian; Kersigo, Jennifer; Jahan, Israt; Pan, Ning; Fritzsch, Bernd

    2011-01-01

    The bipolar spiral ganglion neurons predominantly delaminate from the growing cochlear duct and migrate to Rosenthal’s canal. They project radial fibers to innervate the organ of Corti (type I neurons to inner hair cells, type II neurons to outer hair cells) and also project tonotopically to the cochlear nuclei. The early differentiation of these neurons requires transcription factors to regulate migration, pathfinding and survival. Neurog1 null mice lack formation of neurons. Neurod1 null mice show massive cell death combined with aberrant central and peripheral projections. Prox1 protein is necessary for proper type II neuron process navigation, which is also affected by the neurotrophins Bdnf and Ntf3. Neurotrophin null mutants show specific patterns of neuronal loss along the cochlea but remaining neurons compensate by expanding their target area. All neurotrophin mutants have reduced radial fiber growth proportional to the degree of loss of neurotrophin alleles. This suggests a simple dose response effect of neurotrophin concentration. Keeping overall concentration constant, but misexpressing one neurotrophin under regulatory control of another one results in exuberant fiber growth not only of vestibular fibers to the cochlea but also of spiral ganglion neurons to outer hair cells suggesting different effectiveness of neurotrophins for spiral ganglion neurite growth. Finally, we report here for the first time that losing all neurons in double null mutants affects extension of the cochlear duct and leads to formation of extra rows of outer hair cells in the apex, possibly by disrupting the interaction of the spiral ganglion with the elongating cochlea. PMID:21414397

  9. Intracellular calcium dynamics and membrane conductance changes evoked by Deiters' cell purinoceptor activation in the organ of Corti.

    PubMed

    Lagostena, L; Mammano, F

    2001-03-01

    Deiters' cells function as supporting cells for the sensory-motor outer hair cells of the mammalian cochlea and are interconnected by gap junctions. Here the electrical and Ca2+ responses of Deiters' cells evoked by purinergic stimulation were investigated in the organ of Corti, the auditory sensory epithelium. Adenosine 59-triphosphate (ATP, 50-100 microM) applied focally by pressure increased the intracellular free Ca2+ concentration ([Ca2+]i). At the same time ATP evoked an early inward current that was followed by an outward component, reflecting a sustained Ca2+-dependent reduction of the pre-stimulus offset current. These responses were maintained when Ca2+ was removed from the extracellular medium (0 [Ca2+]o), indicating a contribution to Ca2+ signalling from P2Y metabotropic receptors. UV photolysis of caged inositol 1,4,5-triphosphate (InsP3, 16 microM) produced Ca2+ responses similar to those evoked by exogenous ATP, accompanied by reduction of the offset current. In Deiters' cells uncoupled by octanol (1mM), ATP activated only the early inward current, suggesting that functional gap junctions are required in the late phase of the current responses. Following the delivery of UV flashes to pairs of Deiters' cells loaded with caged InsP3, the electrical coupling ratio (CR), monitored by double patch-clamp recordings, was strongly attenuated. These data support the idea that, by promoting inflow of cations and by controlling gap-junction conductance in a Ca2+-and InsP3-dependent way, ATP might serve a protective role in the cochlea. PMID:11162856

  10. A new genus and species for the first recorded cave-dwelling Cavernicola (Platyhelminthes) from South America

    PubMed Central

    Leal-Zanchet, Ana Maria; de Souza, Stella Teles; Ferreira, Rodrigo Lopes

    2014-01-01

    Abstract Species diversity of Brazilian cave fauna has been seriously underestimated. A karst area located in Felipe Guerra, northeastern Brazil, which is a hotspot of subterranean diversity in Brazil, has revealed more than 20 troglobitic species, most of them still undescribed. Based on recent samplings in this karst area, we document the occurrence of the suborder Cavernicola (Platyhelminthes) in South American hypogean environments for the first time and describe a new genus and species for this suborder. Hausera Leal-Zanchet & Souza, gen. n. has features concordant with those defined for the family Dimarcusidae. The new genus is characterized by two unique features, viz. an intestine extending dorsally to the brain and ovovitelline ducts located dorsally to the nerve cords, which is complemented by a combination of other characters. The type-specimens of Hausera hauseri Leal-Zanchet & Souza, sp. n. are typical stygobionts, unpigmented and eyeless, and they may constitute an oceanic relict as is the case of other stygobiotic invertebrates found in this karst area in northeastern Brazil. PMID:25349486

  11. No evidence for a culturable bacterial tetrodotoxin producer in Pleurobranchaea maculata (Gastropoda: Pleurobranchidae) and Stylochoplana sp. (Platyhelminthes: Polycladida).

    PubMed

    Salvitti, Lauren R; Wood, Susanna A; McNabb, Paul; Cary, Stephen Craig

    2015-02-01

    Tetrodotoxin (TTX) is a potent neurotoxin found in the tissues of many taxonomically diverse organisms. Its origin has been the topic of much debate, with suggestions including endogenous production, acquisition through diet, and symbiotic bacterial synthesis. Bacterial production of TTX has been reported in isolates from marine biota, but at lower than expected concentrations. In this study, 102 strains were isolated from Pleurobranchaea maculata (Opisthobranchia) and Stylochoplana sp. (Platyhelminthes). Tetrodotoxin production was tested utilizing a recently developed sensitive method to detect the C9 base of TTX via liquid chromatography-mass spectrometry. Bacterial strains were characterized by sequencing a region of the 16S ribosomal RNA gene. To account for the possibility that TTX is produced by a consortium of bacteria, a series of experiments using marine broth spiked with various P. maculata tissues were undertaken. Sixteen unique strains from P. maculata and one from Stylochoplana sp. were isolated, representing eight different genera; Pseudomonadales, Actinomycetales, Oceanospirillales, Thiotrichales, Rhodobacterales, Sphingomonadales, Bacillales, and Vibrionales. Molecular fingerprinting of bacterial communities from broth experiments showed little change over the first four days. No C9 base or TTX was detected in isolates or broth experiments (past day 0), suggesting a culturable microbial source of TTX in P. maculata and Stylochoplana sp. is unlikely. PMID:25635464

  12. Evolutionary history of the Tricladida and the Platyhelminthes: an up-to-date phylogenetic and systematic account.

    PubMed

    Riutort, Marta; Álvarez-Presas, Marta; Lázaro, Eva; Solà, Eduard; Paps, Jordi

    2012-01-01

    Within the free-living platyhelminths, the triclads, or planarians, are the best-known group, largely as a result of long-standing and intensive research on regeneration, pattern formation and Hox gene expression. However, the group's evolutionary history has been long debated, with controversies ranging from their phyletic structure and position within the Metazoa to the relationships among species within the Tricladida. Over the the last decade, with the advent of molecular phylogenies, some of these issues have begun to be resolved. Here, we present an up-to-date summary of the main phylogenetic changes and novelties with some comments on their evolutionary implications. The phylum has been split into two groups, and the position of the main group (the Rhabdithophora and the Catenulida), close to the Annelida and the Mollusca within the Lophotrochozoa, is now clear. Their internal relationships, although not totally resolved, have been clarified. Tricladida systematics has also experienced a revolution since the implementation of molecular data. The terrestrial planarians have been demonstrated to have emerged from one of the freshwater families, giving a different view of their evolution and greatly altering their classification. The use of molecular data is also facilitating the identification of Tricladida species by DNA barcoding, allowing better knowledge of their distribution and genetic diversity. Finally, molecular phylogenetic and phylogeographical analyses, taking advantage of recent data, are beginning to give a clear picture of the recent history of the Dugesia and Schmidtea species in the Mediterranean. PMID:22450992

  13. Complete Sequence of the mitochondrial genome of the tapeworm Hymenolepis diminuta: Gene arrangements indicate that platyhelminths are eutrochozoans

    SciTech Connect

    von Nickisch-Rosenegk, Markus; Brown, Wesley M.; Boore, Jeffrey L.

    2001-01-01

    Using ''long-PCR'' we have amplified in overlapping fragments the complete mitochondrial genome of the tapeworm Hymenolepis diminuta (Platyhelminthes: Cestoda) and determined its 13,900 nucleotide sequence. The gene content is the same as that typically found for animal mitochondrial DNA (mtDNA) except that atp8 appears to be lacking, a condition found previously for several other animals. Despite the small size of this mtDNA, there are two large non-coding regions, one of which contains 13 repeats of a 31 nucleotide sequence and a potential stem-loop structure of 25 base pairs with an 11-member loop. Large potential secondary structures are identified also for the non-coding regions of two other cestode mtDNAs. Comparison of the mitochondrial gene arrangement of H. diminuta with those previously published supports a phylogenetic position of flatworms as members of the Eutrochozoa, rather than being basal to either a clade of protostomes or a clade of coelomates.

  14. No Evidence for a Culturable Bacterial Tetrodotoxin Producer in Pleurobranchaea maculata (Gastropoda: Pleurobranchidae) and Stylochoplana sp. (Platyhelminthes: Polycladida)

    PubMed Central

    Salvitti, Lauren R.; Wood, Susanna A.; McNabb, Paul; Cary, Stephen Craig

    2015-01-01

    Tetrodotoxin (TTX) is a potent neurotoxin found in the tissues of many taxonomically diverse organisms. Its origin has been the topic of much debate, with suggestions including endogenous production, acquisition through diet, and symbiotic bacterial synthesis. Bacterial production of TTX has been reported in isolates from marine biota, but at lower than expected concentrations. In this study, 102 strains were isolated from Pleurobranchaea maculata (Opisthobranchia) and Stylochoplana sp. (Platyhelminthes). Tetrodotoxin production was tested utilizing a recently developed sensitive method to detect the C9 base of TTX via liquid chromatography—mass spectrometry. Bacterial strains were characterized by sequencing a region of the 16S ribosomal RNA gene. To account for the possibility that TTX is produced by a consortium of bacteria, a series of experiments using marine broth spiked with various P. maculata tissues were undertaken. Sixteen unique strains from P. maculata and one from Stylochoplana sp. were isolated, representing eight different genera; Pseudomonadales, Actinomycetales, Oceanospirillales, Thiotrichales, Rhodobacterales, Sphingomonadales, Bacillales, and Vibrionales. Molecular fingerprinting of bacterial communities from broth experiments showed little change over the first four days. No C9 base or TTX was detected in isolates or broth experiments (past day 0), suggesting a culturable microbial source of TTX in P. maculata and Stylochoplana sp. is unlikely. PMID:25635464

  15. The free energy of the metastable supersaturated vapor via restricted ensemble simulations. III. An extension to the Corti and Debenedetti subcell constraint algorithm

    NASA Astrophysics Data System (ADS)

    Nie, Chu; Geng, Jun; Marlow, William H.

    2016-04-01

    In order to improve the sampling of restricted microstates in our previous work [C. Nie, J. Geng, and W. H. Marlow, J. Chem. Phys. 127, 154505 (2007); 128, 234310 (2008)] and quantitatively predict thermal properties of supersaturated vapors, an extension is made to the Corti and Debenedetti subcell constraint algorithm [D. S. Corti and P. Debenedetti, Chem. Eng. Sci. 49, 2717 (1994)], which restricts the maximum allowed local density at any point in a simulation box. The maximum allowed local density at a point in a simulation box is defined by the maximum number of particles Nm allowed to appear inside a sphere of radius R, with this point as the center of the sphere. Both Nm and R serve as extra thermodynamic variables for maintaining a certain degree of spatial homogeneity in a supersaturated system. In a restricted canonical ensemble, at a given temperature and an overall density, series of local minima on the Helmholtz free energy surface F(Nm, R) are found subject to different (Nm, R) pairs. The true equilibrium metastable state is identified through the analysis of the formation free energies of Stillinger clusters of various sizes obtained from these restricted states. The simulation results of a supersaturated Lennard-Jones vapor at reduced temperature 0.7 including the vapor pressure isotherm, formation free energies of critical nuclei, and chemical potential differences are presented and analyzed. In addition, with slight modifications, the current algorithm can be applied to computing thermal properties of superheated liquids.

  16. The free energy of the metastable supersaturated vapor via restricted ensemble simulations. III. An extension to the Corti and Debenedetti subcell constraint algorithm.

    PubMed

    Nie, Chu; Geng, Jun; Marlow, William H

    2016-04-14

    In order to improve the sampling of restricted microstates in our previous work [C. Nie, J. Geng, and W. H. Marlow, J. Chem. Phys. 127, 154505 (2007); 128, 234310 (2008)] and quantitatively predict thermal properties of supersaturated vapors, an extension is made to the Corti and Debenedetti subcell constraint algorithm [D. S. Corti and P. Debenedetti, Chem. Eng. Sci. 49, 2717 (1994)], which restricts the maximum allowed local density at any point in a simulation box. The maximum allowed local density at a point in a simulation box is defined by the maximum number of particles Nm allowed to appear inside a sphere of radius R, with this point as the center of the sphere. Both Nm and R serve as extra thermodynamic variables for maintaining a certain degree of spatial homogeneity in a supersaturated system. In a restricted canonical ensemble, at a given temperature and an overall density, series of local minima on the Helmholtz free energy surface F(Nm, R) are found subject to different (Nm, R) pairs. The true equilibrium metastable state is identified through the analysis of the formation free energies of Stillinger clusters of various sizes obtained from these restricted states. The simulation results of a supersaturated Lennard-Jones vapor at reduced temperature 0.7 including the vapor pressure isotherm, formation free energies of critical nuclei, and chemical potential differences are presented and analyzed. In addition, with slight modifications, the current algorithm can be applied to computing thermal properties of superheated liquids. PMID:27083734

  17. Diversity, specificity and speciation in larval Diplostomidae (Platyhelminthes: Digenea) in the eyes of freshwater fish, as revealed by DNA barcodes.

    PubMed

    Locke, Sean A; Al-Nasiri, Fatima S; Caffara, Monica; Drago, Fabiana; Kalbe, Martin; Lapierre, Angela Rose; McLaughlin, J Daniel; Nie, Pin; Overstreet, Robin M; Souza, Geza T R; Takemoto, Ricardo M; Marcogliese, David J

    2015-11-01

    Larvae (metacercariae) in some species of Diplostomidae (Platyhelminthes: Digenea) inhabit fish eyes and are difficult to identify to species based on morphology. DNA barcoding has clarified the diversity and life cycles of diplostomids in North America, Europe and Africa, but has seldom been used in parasites sampled in large numbers or at large spatial scales. Here, distance-based analysis of cytochrome c oxidase 1 barcodes and, in some specimens, internal transcribed spacer (ITS-1, 5.8S, ITS-2) sequences was performed for over 2000 diplostomids from Africa, the Middle East, Europe, Asia and the Americas. Fifty-two species of Diplostomum, Tylodelphys and Austrodiplostomum (Digenea: Diplostomidae) were distinguished. The 52 species comprise 12 identified species, six species in two species complexes and 34 putative species, and 33/52 had been delineated in previous studies. Most (23/40) of the unidentified, putative species distinguished by cytochrome c oxidase 1 distances were supported by at least one additional line of evidence. As the intensity of sampling of the 52 species increased, variation in cytochrome c oxidase 1 decreased between and increased within species, while the spatial scale at which species were sampled had no effect. Nonetheless, variation between species always exceeded variation within species. New life-cycle linkages, geographic and host records, and genetic data were recorded in several species, including Tylodelphys jenynsiae, Tylodelphys immer and Diplostomum ardeae. Species of Diplostomum inhabiting the lens are less host-specific and less numerous than those infecting other tissues, suggesting that reduced immune activity in the lens has influenced rates of speciation. PMID:26276524

  18. Two dimensional vibrations of the guinea pig apex organ of Corti measured in vivo using phase sensitive Fourier domain optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Ramamoorthy, Sripriya; Zhang, Yuan; Petrie, Tracy; Fridberger, Anders; Ren, Tianying; Wang, Ruikang; Jacques, Steven L.; Nuttall, Alfred L.

    2015-02-01

    In this study, we measure the in vivo apical-turn vibrations of the guinea pig organ of Corti in both axial and radial directions using phase-sensitive Fourier domain optical coherence tomography. The apical turn in guinea pig cochlea has best frequencies around 100 - 500 Hz which are relevant for human speech. Prior measurements of vibrations in the guinea pig apex involved opening the otic capsule, which has been questioned on the basis of the resulting changes to cochlear hydrodynamics. Here this limitation is overcome by measuring the vibrations through bone without opening the otic capsule. Furthermore, we have significantly reduced the surgery needed to access the guinea pig apex in the axial direction by introducing a miniature mirror inside the bulla. The method and preliminary data are discussed in this article.

  19. Generation of highly-reactive oxygen species is closely related to hair cell damage in rat organ of Corti treated with gentamicin.

    PubMed

    Choung, Y H; Taura, A; Pak, K; Choi, S J; Masuda, M; Ryan, A F

    2009-06-16

    Reactive oxygen species (ROS) have been suggested to play a major role in aminoglycoside-induced hair cell (HC) loss, but are difficult to detect. Moreover, ROS can occur normally in cells where they have roles in metabolism, cell signaling and other processes. Two new probes, aminophenyl fluorescein (APF) and hydroxyphenyl fluorescein (HPF) are dyes which selectively detect highly-reactive oxygen species (hROS), those most associated with cellular damage. We assessed the presence of hROS in the neonatal rat organ of Corti during chronic exposure to 50 microM gentamicin in vitro, to examine the relationship between cell damage and hROS across HC type and across the three cochlear turns. hROS were initially detected at 48 hours (h), with an increase at 72 h and persistence until at least 96 h. At 48 h, hROS were restricted to outer HCs and occurred prior to loss of stereocilia. At 72 h, outer HCs showed both hROS and stereocilia loss, and hROS were noted in a few inner HCs. Basal turn HCs showed more hROS than middle turn HCs. Very little hROS accumulation or stereocilia loss was observed in the apical turn, even at 72 h. First row outer HCs were most vulnerable to gentamicin-induced hROS, followed by second and then third row outer HCs. Inner HCs behaved similarly to third row outer HCs. By 96 h stereocilia damage was extensive, but surviving HCs showed persisting fluorescence. APF consistently showed more fluorescence than HPF. The results suggest that hROS accumulation is an important initial step in gentamicin-induced HC damage, and that the differential sensitivity of HCs in the organ of Corti is closely related to differences in hROS accumulation. PMID:19318119

  20. Molecular characterization of Gastrothylax crumenifer (Platyhelminthes: Gastrothylacidae) from goats in the western part of India by LSU of nuclear ribosomal DNA.

    PubMed

    Kumar, Ashwani; Chaudhary, Anshu; Verma, Chandni; Singh, Hridaya Shanker

    2014-12-01

    The rumen parasite, Gastrothylax crumenifer (Platyhelminthes: Gastrothylacidae), is a highly pathogenic trematode parasite of goat (Capra hircus). It sucks blood that causes acute disease like anemia, and severe economic losses occur due to morbidity and mortality of the ruminant infected by these worms. The study of these rumen paramphistomes, their infection, and public health importance remains unclear in India especially in the western part of state Uttar Pradesh (U.P.), Meerut, India, where the goat meat consumption is very high. This paper provides the molecular characterization of G. crumenifer recovered from the rumen of Capra hircus from Meerut, U.P., India by the partial sequence of 28S rDNA. Nucleotide sequence similarity searching on BLAST of 28S rDNA from parasites showed the highest identity with those of G. crumenifer from the same host Capra hircus. This is the first report of molecular identification of G. crumenifer from this part of India. PMID:25548426

  1. Transfection of Platyhelminthes

    PubMed Central

    Moguel, Bárbara; Bobes, Raúl J.; Carrero, Julio C.; Laclette, Juan P.

    2015-01-01

    Flatworms are one of the most diverse groups within Lophotrochozoa with more than 20,000 known species, distributed worldwide in different ecosystems, from the free-living organisms in the seas and lakes to highly specialized parasites living in a variety of hosts, including humans. Several infections caused by flatworms are considered major neglected diseases affecting countries in the Americas, Asia, and Africa. For several decades, a particular interest on free-living flatworms was due to their ability to regenerate considerable portions of the body, implying the presence of germ cells that could be important for medicine. The relevance of reverse genetics for this group is clear; understanding the phenotypic characteristics of specific genes will shed light on developmental traits of free-living and parasite worms. The genetic manipulation of flatworms will allow learning more about the mechanisms for tissue regeneration, designing new and more effective anthelmintic drugs, and explaining the host-parasite molecular crosstalk so far partially inaccessible for experimentation. In this review, availability of transfection techniques is analyzed across flatworms, from the initial transient achievements to the stable manipulations now developed for free-living and parasite species. PMID:26090388

  2. Traveling waves on the organ of Corti of the chinchilla cochlea: spatial trajectories of inner hair cell depolarization inferred from responses of auditory-nerve fibers

    PubMed Central

    Temchin, Andrei N.; Recio-Spinoso, Alberto; Cai, Hongxue; Ruggero, Mario A.

    2012-01-01

    Spatial magnitude and phase profiles for inner hair cell depolarization throughout the chinchilla cochlea were inferred from responses of auditory-nerve fibers to threshold- and moderate-level tones and tone complexes. Firing-rate profiles for frequencies ≤ 2 kHz are bimodal, with the major peak at the characteristic place and a secondary peak at 3–5 mm from the extreme base. Response-phase trajectories are synchronous with peak outward stapes displacement at the extreme cochlear base and accumulate 1.5-period lags at the characteristic places. High-frequency phase trajectories are very similar to the trajectories of basilar-membrane peak velocity toward scala tympani. Low-frequency phase trajectories undergo a polarity flip in a region, 6.5–9 mm from the cochlear base, where traveling-wave phase velocity attains a local minimum and a local maximum and where the onset latencies of near-threshold impulse responses computed from responses to near-threshold white noise exhibit a local minimum. That region is the same where frequency-threshold tuning curves of auditory-nerve fibers undergo a shape transition. Since depolarization of inner hair cells presumably indicates the mechanical stimulus to their stereocilia, the present results suggest that distinct low-frequency forward waves of organ of Corti vibration are launched simultaneously at the extreme base of the cochlea and at the 6.5–9 mm transition region, from where antiphasic reflections arise. PMID:22855802

  3. Polygenic inheritance of sensorineural hearing loss (Snhl2, -3, and -4) and organ of Corti patterning defect in the ALR/LtJ mouse strain.

    PubMed

    Latoche, Joseph R; Neely, Harold R; Noben-Trauth, Konrad

    2011-05-01

    Progressive sensorineural hearing loss in humans is a common and debilitating impairment. Sensorineural deafness in inbred strains of mice is a similarly common and genetically diverse phenotype providing experimental models to study the underlying genetics and the biological effects of the risk factors. Here, we report that ALR/LtJ mice develop early-onset profound sensorineural hearing loss as evidenced by high-to-low frequency hearing threshold shifts, absent distortion-product otoacoustic emissions, and normal endocochlear potentials. Linkage analyses of a segregating backcross revealed three novel quantitative trait loci named sensorineural hearing loss (Snhl) -2, -3, and -4. The QTLs achieved very high LOD scores with markers on chromosome 1 (Snhl2, LOD: 12), chromosome 6 (Snhl3, LOD: 24) and chromosome 10 (Snhl4, LOD: 11). Together, they explained 90% of the phenotypic variance. While Snhl2 and Snhl3 affected hearing thresholds across a broad range of test frequencies, Snhl4 caused primarily high-frequency hearing loss. The hearing impairment is accompanied by an organ of Corti patterning defect that is characterized by the ectopic expression of supernumerary outer hair cells organized in rows along the abneural site of the sensory epithelium in the presence of unaltered planar polarity and otherwise normal cochlear duct morphology. Cloning the Snhl2, -3, and -4 genes in the ALR/LtJ mice may provide important genetic and mechanistic insights into the pathology of human progressive sensorineural deafness. PMID:21185929

  4. Phase-sensitive optical coherence tomography imaging of the tissue motion within the organ of Corti at a subnanometer scale: a preliminary study

    NASA Astrophysics Data System (ADS)

    Wang, Ruikang K.; Nuttall, Alfred L.

    2010-09-01

    Hearing loss can mean severe impairment to the quality of life. However, the biomechanical mechanisms of how the hearing organ, i.e., the organ of Corti (OC), responds to sound are still elusive, largely because there is currently no means available to image the 3-D motion characteristics of the OC. We present a novel use of the phase-sensitive spectral domain optical coherence tomography (PSOCT) to characterize the motion of cellular compartments within the OC at a subnanometer scale. The PSOCT system operates at 1310 nm with a spatial resolution of ~16 μm and an imaging speed of 47,000 A-lines/s. The phase changes of the spectral interferograms induced by the localized tissue motion are used to quantify the vibration magnitude. Fourier transform analysis of the phase changes improves the system sensitivity to sense minute vibrations smaller than 1 nm. We demonstrate that the PSOCT system is feasible to image the meaningful vibration of cellular compartments within the OC with an unprecedented sensitivity down to ~0.5 A˚.

  5. MAP3K1 function is essential for cytoarchitecture of the mouse organ of Corti and survival of auditory hair cells.

    PubMed

    Yousaf, Rizwan; Meng, Qinghang; Hufnagel, Robert B; Xia, Ying; Puligilla, Chandrakala; Ahmed, Zubair M; Riazuddin, Saima

    2015-12-01

    MAP3K1 is a serine/threonine kinase that is activated by a diverse set of stimuli and exerts its effect through various downstream effecter molecules, including JNK, ERK1/2 and p38. In humans, mutant alleles of MAP3K1 are associated with 46,XY sex reversal. Until recently, the only phenotype observed in Map3k1(tm1Yxia) mutant mice was open eyelids at birth. Here, we report that homozygous Map3k1(tm1Yxia) mice have early-onset profound hearing loss accompanied by the progressive degeneration of cochlear outer hair cells. In the mouse inner ear, MAP3K1 has punctate localization at the apical surface of the supporting cells in close proximity to basal bodies. Although the cytoarchitecture, neuronal wiring and synaptic junctions in the organ of Corti are grossly preserved, Map3k1(tm1Yxia) mutant mice have supernumerary functional outer hair cells (OHCs) and Deiters' cells. Loss of MAP3K1 function resulted in the downregulation of Fgfr3, Fgf8, Fgf10 and Atf3 expression in the inner ear. Fgfr3, Fgf8 and Fgf10 have a role in induction of the otic placode or in otic epithelium development in mice, and their functional deficits cause defects in cochlear morphogenesis and hearing loss. Our studies suggest that MAP3K1 has an essential role in the regulation of these key cochlear morphogenesis genes. Collectively, our data highlight the crucial role of MAP3K1 in the development and function of the mouse inner ear and hearing. PMID:26496772

  6. Transplantation and survival of mouse inner ear progenitor/stem cells in the organ of Corti after cochleostomy of hearing-impaired guinea pigs: preliminary results.

    PubMed

    Barboza, L C M; Lezirovitz, K; Zanatta, D B; Strauss, B E; Mingroni-Netto, R C; Oiticica, J; Haddad, L A; Bento, R F

    2016-01-01

    In mammals, damage to sensory receptor cells (hair cells) of the inner ear results in permanent sensorineural hearing loss. Here, we investigated whether postnatal mouse inner ear progenitor/stem cells (mIESCs) are viable after transplantation into the basal turns of neomycin-injured guinea pig cochleas. We also examined the effects of mIESC transplantation on auditory functions. Eight adult female Cavia porcellus guinea pigs (250-350 g) were deafened by intratympanic neomycin delivery. After 7 days, the animals were randomly divided in two groups. The study group (n=4) received transplantation of LacZ-positive mIESCs in culture medium into the scala tympani. The control group (n=4) received culture medium only. At 2 weeks after transplantation, functional analyses were performed by auditory brainstem response measurement, and the animals were sacrificed. The presence of mIESCs was evaluated by immunohistochemistry of sections of the cochlea from the study group. Non-parametric tests were used for statistical analysis of the data. Intratympanic neomycin delivery damaged hair cells and increased auditory thresholds prior to cell transplantation. There were no significant differences between auditory brainstem thresholds before and after transplantation in individual guinea pigs. Some mIESCs were observed in all scalae of the basal turns of the injured cochleas, and a proportion of these cells expressed the hair cell marker myosin VIIa. Some transplanted mIESCs engrafted in the cochlear basilar membrane. Our study demonstrates that transplanted cells survived and engrafted in the organ of Corti after cochleostomy. PMID:27007652

  7. Transplantation and survival of mouse inner ear progenitor/stem cells in the organ of Corti after cochleostomy of hearing-impaired guinea pigs: preliminary results

    PubMed Central

    Barboza, L.C.M.; Lezirovitz, K.; Zanatta, D.B.; Strauss, B.E.; Mingroni-Netto, R.C.; Oiticica, J.; Haddad, L.A.; Bento, R.F.

    2016-01-01

    In mammals, damage to sensory receptor cells (hair cells) of the inner ear results in permanent sensorineural hearing loss. Here, we investigated whether postnatal mouse inner ear progenitor/stem cells (mIESCs) are viable after transplantation into the basal turns of neomycin-injured guinea pig cochleas. We also examined the effects of mIESC transplantation on auditory functions. Eight adult female Cavia porcellus guinea pigs (250-350g) were deafened by intratympanic neomycin delivery. After 7 days, the animals were randomly divided in two groups. The study group (n=4) received transplantation of LacZ-positive mIESCs in culture medium into the scala tympani. The control group (n=4) received culture medium only. At 2 weeks after transplantation, functional analyses were performed by auditory brainstem response measurement, and the animals were sacrificed. The presence of mIESCs was evaluated by immunohistochemistry of sections of the cochlea from the study group. Non-parametric tests were used for statistical analysis of the data. Intratympanic neomycin delivery damaged hair cells and increased auditory thresholds prior to cell transplantation. There were no significant differences between auditory brainstem thresholds before and after transplantation in individual guinea pigs. Some mIESCs were observed in all scalae of the basal turns of the injured cochleas, and a proportion of these cells expressed the hair cell marker myosin VIIa. Some transplanted mIESCs engrafted in the cochlear basilar membrane. Our study demonstrates that transplanted cells survived and engrafted in the organ of Corti after cochleostomy. PMID:27007652

  8. MAP3K1 function is essential for cytoarchitecture of the mouse organ of Corti and survival of auditory hair cells

    PubMed Central

    Yousaf, Rizwan; Meng, Qinghang; Hufnagel, Robert B.; Xia, Ying; Puligilla, Chandrakala; Ahmed, Zubair M.; Riazuddin, Saima

    2015-01-01

    ABSTRACT MAP3K1 is a serine/threonine kinase that is activated by a diverse set of stimuli and exerts its effect through various downstream effecter molecules, including JNK, ERK1/2 and p38. In humans, mutant alleles of MAP3K1 are associated with 46,XY sex reversal. Until recently, the only phenotype observed in Map3k1tm1Yxia mutant mice was open eyelids at birth. Here, we report that homozygous Map3k1tm1Yxia mice have early-onset profound hearing loss accompanied by the progressive degeneration of cochlear outer hair cells. In the mouse inner ear, MAP3K1 has punctate localization at the apical surface of the supporting cells in close proximity to basal bodies. Although the cytoarchitecture, neuronal wiring and synaptic junctions in the organ of Corti are grossly preserved, Map3k1tm1Yxia mutant mice have supernumerary functional outer hair cells (OHCs) and Deiters' cells. Loss of MAP3K1 function resulted in the downregulation of Fgfr3, Fgf8, Fgf10 and Atf3 expression in the inner ear. Fgfr3, Fgf8 and Fgf10 have a role in induction of the otic placode or in otic epithelium development in mice, and their functional deficits cause defects in cochlear morphogenesis and hearing loss. Our studies suggest that MAP3K1 has an essential role in the regulation of these key cochlear morphogenesis genes. Collectively, our data highlight the crucial role of MAP3K1 in the development and function of the mouse inner ear and hearing. PMID:26496772

  9. Light and electron microscopic studies of the intestinal epithelium in Notoplana humilis (Platyhelminthes, Polycladida): the contribution of mesodermal/gastrodermal neoblasts to intestinal regeneration.

    PubMed

    Okano, Daisuke; Ishida, Sachiko; Ishiguro, Sei-ichi; Kobayashi, Kazuya

    2015-12-01

    Some free-living flatworms in the phylum Platyhelminthes possess strong regenerative capability that depends on putative pluripotent stem cells known as neoblasts. These neoblasts are defined based on several criteria, including their proliferative capacity and the presence of cellular components known as chromatoid bodies. Polyclads, which are marine flatworms, have the potential to be a good model system for stem cell research, yet little information is available regarding neoblasts and regeneration. In this study, transmission electron microscopy and immunostaining analyses, using antibodies against phospho-histone H3 and BrdU, were used to identify two populations of neoblasts in the polyclad Notoplana humilis: mesodermal neoblasts (located in the mesenchymal space) and gastrodermal neoblasts (located within the intestine, where granular club cells and phagocytic cells are also located). Light and electron microscopic analyses also suggested that phagocytic cells and mesodermal/gastrodermal neoblasts, but not granular club cells, migrated into blastemas and remodeled the intestine during regeneration. Therefore, we suggest that, in polyclads, intestinal regeneration is accomplished by mechanisms underlying both morphallaxis (remodeling of pre-existing tissues) and epimorphosis (de novo tissue formation derived from mesodermal/gastrodermal neoblasts). Based on the assumption that gastrodermal neoblasts, which are derived from mesodermal neoblasts, are intestinal stem cells, we propose a model to study intestinal regeneration. PMID:26104134

  10. Lineage tracing of Sox2-expressing progenitor cells in the mouse inner ear reveals a broad contribution to non-sensory tissues and insights into the origin of the organ of Corti.

    PubMed

    Gu, Rende; Brown, Rogers M; Hsu, Chih-Wei; Cai, Tiantian; Crowder, Alyssa L; Piazza, Victor G; Vadakkan, Tegy J; Dickinson, Mary E; Groves, Andrew K

    2016-06-01

    The transcription factor Sox2 is both necessary and sufficient for the generation of sensory regions of the inner ear. It regulates expression of the Notch ligand Jag1 in prosensory progenitors, which signal to neighboring cells to up-regulate Sox2 and sustain prosensory identity. However, the expression pattern of Sox2 in the early inner ear is very broad, suggesting that Sox2-expressing progenitors form a wide variety of cell types in addition to generating the sensory regions of the ear. We used Sox2-CreER mice to follow the fates of Sox2-expressing cells at different stages in ear development. We find that Sox2-expressing cells in the early otocyst give rise to large numbers of non-sensory structures throughout the inner ear, and that Sox2 only becomes a truly prosensory marker at embryonic day (E)11.5. Our fate map reveals the organ of Corti derives from a central domain on the medial side of the otocyst and shows that a significant amount of the organ of Corti derives from a Sox2-negative population in this region. PMID:27090805

  11. News Conference: Brecon hosts 10th teacher's conference Summer school: Science summer school heads to Crete Award: The Corti Science Prize Radioactivity: Scottish beach is no beta off Workshop: Heureka project promotes teaching Experiments: Spanish project proves that learning science can be exciting Lecture: IOP schools lecture journeys from x-rays to antimatter Correction to the news item 'Delegates experience universality' Forthcoming events

    NASA Astrophysics Data System (ADS)

    2012-01-01

    Conference: Brecon hosts 10th teacher's conference Summer school: Science summer school heads to Crete Award: The Corti Science Prize Radioactivity: Scottish beach is no beta off Workshop: Heureka project promotes teaching Experiments: Spanish project proves that learning science can be exciting Lecture: IOP schools lecture journeys from x-rays to antimatter Correction to the news item 'Delegates experience universality' Forthcoming events

  12. News Particle Physics: ATLAS unveils mural at CERN Prize: Corti Trust invites essay entries Astrophysics: CERN holds cosmic-ray conference Researchers in Residence: Lord Winston returns to school Music: ATLAS scientists record physics music Conference: Champagne flows at Reims event Competition: Students triumph at physics olympiad Teaching: Physics proves popular in Japanese schools Forthcoming Events

    NASA Astrophysics Data System (ADS)

    2011-01-01

    Particle Physics: ATLAS unveils mural at CERN Prize: Corti Trust invites essay entries Astrophysics: CERN holds cosmic-ray conference Researchers in Residence: Lord Winston returns to school Music: ATLAS scientists record physics music Conference: Champagne flows at Reims event Competition: Students triumph at physics olympiad Teaching: Physics proves popular in Japanese schools Forthcoming Events

  13. Gyrodactylus salinae n. sp. (Platyhelminthes: Monogenea) infecting the south European toothcarp Aphanius fasciatus (Valenciennes) (Teleostei, Cyprinodontidae) from a hypersaline environment in Italy

    PubMed Central

    2011-01-01

    Background Historically, non-native species of Gambusia (Poeciliidae) have been used to control larval stages of the Asian tiger mosquito, Stegomyia albopicta Reinert, Harbach et Kitching, 2004 throughout Italy. The potential utility of indigenous populations of Aphanius fasciatus (Valenciennes) (Teleostei: Cyprinodontidae) as an appropriate alternative biological control is currently being explored. A sub-sample of ten fish collected from Cervia Saline, Italy (salinity 65 ppt; 30°C) to assess their reproductive capability in captivity, harboured a moderate infection of Gyrodactylus von Nordmann, 1832 (Platyhelminthes, Monogenea). A subsequent morphological and molecular study identified this as being a new species. Results Gyrodactylus salinae n. sp. is described from the skin, fins and gills of A. fasciatus. Light and scanning electron microscopical (SEM) examination of the opisthaptoral armature and their comparison with all other recorded species suggested morphological similarities to Gyrodactylus rugiensoides Huyse et Volckaert, 2002 from Pomatoschistus minutus (Pallas). Features of the ventral bar, however, permit its discrimination from G. rugiensoides. Sequencing of the nuclear ribosomal DNA internal transcribed spacers 1 and 2 and the 5.8S rRNA gene and a comparison with all species listed in GenBank confirmed they are unique and represent a new species (most similar to Gyrodactylus anguillae Ergens, 1960, 8.3% pair-wise distance based on 5.8S+ITS2). This represents the first species of Gyrodactylus to be described from Aphanius and, to date, has the longest ITS1 (774 bp) sequenced from any Gyrodactylus. Additional sampling of Cervia Saline throughout the year, found G. salinae n. sp. to persist in conditions ranging from 35 ppt and 5°C in December to 65 ppt and 30°C in July, while in captivity a low level of infection was present, even in freshwater conditions (0 ppt). Conclusions The ability of G. salinae n. sp. to tolerate a wide range of salinities

  14. Evolutionary processes involved in the diversification of chelonian and mammal polystomatid parasites (Platyhelminthes, Monogenea, Polystomatidae) revealed by palaeoecology of their hosts.

    PubMed

    Héritier, Laurent; Badets, Mathieu; Du Preez, Louis H; Aisien, Martins S O; Lixian, Fan; Combes, Claude; Verneau, Olivier

    2015-11-01

    Polystomatid flatworms (Platyhelminthes) are monogenean parasites that infect exclusively aquatic or semi-aquatic sarcopterygians such as the Australian lungfish, amphibians, freshwater turtles and the African common hippopotamus. Previous studies on the phylogenetic relationships of these parasites, excluding Oculotrema hippopotami infecting common hippos, showed a global coevolution between hosts and their parasites at a macroevolutionary scale. These studies also demonstrated a strong correlation between the diversification of early neobatrachian polystomes and Gondwana breakup in the Mesozoic period. However the origin of chelonian polystomes is still in question as a switch from presumably primitive aquatic amniotes to turtles at the time of their first appearance, or soon after during their radiation, was assumed. In order to resolve this sticking point, we extended the phylogeny of polystomes with broader parasite sampling, i.e. 55 polystome species including Nanopolystoma tinsleyi a polystome infecting caecilians and O. hippopotami, and larger set of sequence data covering two nuclear and two mitochondrial genes coding for the ribosomal RNA 18S and 28S, the Cytochrome c Oxidase I and the ribosomal RNA 12S, respectively. The secondary structure of nuclear rRNAs genes (stems and loops) was taken into account for sequence alignments and Bayesian analyses were performed based on the appropriate models of evolution selected independently for the four designed partitions. Molecular calibrations were also conducted for dating the main speciation events in the polystome tree. The phylogenetic position of chelonian parasites that are phylogenetically closer to N. tinsleyi than all other amphibian polystomes and molecular time estimates suggest that these parasites originated following a switch from caecilians, at a geological period when primitive turtles may already have adapted to an aquatic life style, i.e. at about 178Million years ago, or a little later when

  15. Release of O2- and LTC4 by murine eosinophils: role of intra- and extracellular calcium.

    PubMed Central

    de Andres, B; del Pozo, V; Martin, E; Palomino, P; Lahoz, C

    1990-01-01

    Using an experimental model of mouse peritoneal eosinophilia, we investigated the role of Ca2+ in the in vitro activation of these cells challenged with specific Mesocestoides corti antigen. We have detected LTC4, a metabolite derived from arachidonic acid by way of 5'lipo-oxygenase and superoxide anion from the oxidative burst, as inflammatory mediators produced by activated eosinophils. Preincubation with hyperimmune mice serum increases the amount of LTC4 and superoxide anion in response to the antigenic extract. Release of O2- is inhibited by Verapamil (a voltage-gated calcium channel) and Quin 2 (an intracellular trapped chelator of calcium). Also, LTC4 produced by preincubated eosinophils challenged with M. corti is dramatically inhibited by Quin 2. Our results suggest an intact mechanism for calcium control for the release of these inflammatory mediators by eosinophils, after specific antigenic stimulation. PMID:1689695

  16. Delta-Notch Lateral Inhibition within the Organ of Corti

    NASA Astrophysics Data System (ADS)

    Summers, R.; Abdulla, T.; Luff, R.

    2013-09-01

    Lateral inhibition is described as an emergent property of the Delta-Notch signalling network. Two separate model representations of lateral inhibition are proposed for different purposes. One provides information about bioenergetics while the other has the capability to produce a physical representation. It is proposed that both can be used in further studies of the sensory pathways in the human connectome model of brain function.

  17. [Phylogenetic analyses of the family Tetraonchidae (Platyhelminthes: Monogenea)].

    PubMed

    Gerasev, P I

    2004-01-01

    A phylogenetic reconstruction of the monogenean family Tetraonchidae was carried out by methods of parsimony-based cladistics. The analysis included 20 species of tetraonchids and two out-groups (Sundanonchus tomanorum and Dactylogyrus amphibothrium) and was based on 34 morphofunctional characters. Software PAUP 4.0 and Winclada were used for the phylogenetic reconstructions. Obtained results allow proposing a preliminary phylogenetic hypothesis of the family Tetraonchidae along with the discussion of host-parasite association. According to the current taxonomic view, the family Tetraonchidae included two genera. Cladistic analysis showed a monophyly of the family and the genus Tetraonchus Diesing, 1858. Two representative of the former genus, Tetraoncus monenteron and T. borealis, parasitize the pikes (Esocoformes: Esocidae) and the grayling (Salmonidae: Thymallinae) respectively. The genus Salmonchus Spassky et Roytman, 1958 has a complicated structure and its intrageneric relationships were not completely resolved; in general, the analysis allows to recognise several species groups: Salmonchus oncorhynchi--the parasite of the Oncorhynchus masou smolt living during the first year of life in fresh water; four species (S. variabilis, S. gussevi, S. grumosus, S. alaskensis) inhabiting specifically the whitefishes (Salmonidae: Coregoninae); all reminder of Salmonchus species occurring on the salmons (Salmonidae: Salmoninae). The bootstrap test gives a support only for the following clades: family Tetraonchidae (75%), genus Tetraonchus (88%); a group of Salmonchus species associated with the whitefishes (93%) and grouping of four species (S. huhonis, S. pseudolenoki, S. skrjabini and S. lenoki) from the lenoks (Brachymystax) and taimens (Hucho) (61%). PMID:15553772

  18. Microturbellarians (Platyhelminthes and Acoelomorpha) in Brazil: invisible organisms?

    PubMed

    Braccini, J A L; Amaral, S V; Leal-Zanchet, A M

    2016-06-01

    Microturbellarians typically belong to the benthos and may occur in a wide variety of environments. They are abundant in freshwater and marine ecosystems and may occur in moist terrestrial habitats. However, turbellarians are seldom taken into account in studies of biodiversity. Most studies on Brazilian microturbellarians had taxonomical purposes and were done in the years 1940-1950. Thus, information on their occurrence and ecological aspects are dispersed throughout several papers. We intend here to summarize the biogeographical distribution and ecological aspects of microturbellarians recorded for Brazil, indicating the main gaps in their knowledge and possible actions to enhance studies on this group. There are 239 species of microturbellarians registered for Brazil, with records distributed in 12 states. However, just three states located in southern Brazil have records of 94% of microturbellarian species. Thus, knowledge on the systematics and geographical distribution of Brazilian microturbellarians clearly reflect the scientific activity over many years or decades in two states of southeastern and southern Brazil. Considering the scant information on this group in Brazil, which is also the situation of the Neotropical microturbellarians in general, some actions should be proposed. First, it would be necessary to sample in the diverse biomes, as well as in the various river and sea basins, based on standardized sampling protocols. Second, it would be necessary to encourage diverse research groups to include microturbellarians and/or turbellarians in general into biodiversity inventories and studies on community structure of invertebrates. Third, it is necessary to increase the number of research groups on microturbellarians, in order to augment the studies on their morphology, systematics, and ecology. Considering their abundance, species richness and ecological importance in aquatic environments, despite some peculiarities regarding their sampling, sorting and identification procedures, the challenge to study microturbellarians and enhance knowledge about them in Brazilian ecosystems should be faced. PMID:26959945

  19. Mitochondrial gene order change in Schistosoma (Platyhelminthes: Digenea: Schistosomatidae).

    PubMed

    Webster, Bonnie L; Littlewood, D Timothy J

    2012-01-01

    In the flatworm genus Schistosoma, species of which include parasites of biomedical and veterinary importance, mitochondrial gene order is radically different in some species. A PCR-based survey of 19 schistosomatid spp. established which of 14 Schistosoma spp. have the ancestral (plesiomorphic) or derived gene order condition. A phylogeny for Schistosoma was estimated and used to infer the origin of the gene order change which is present in all members of a clade containing Schistosoma incognitum and members of the traditionally recognised Schistosoma indicum, Schistosoma mansoni and Schistosomahaematobium spp. groups. Schistosoma turkestanicum, with the plesiomorphic gene order state, is sister to this clade. Common interval analysis suggests change in gene order, from ancestral to derived, consisted of two sequential transposition events: (a) nad1_nad3 to nad3_nad1 and (b) [atp6,nad2]_[nad3,-nad1,cox1,rrnL,rrnS,cox2,nad6] to [nad3,nad1,cox1,rrnL,rrnS,cox2,nad6]_[atp6,nad2], where gene order offragments within square brackets remain unchanged. Gene order change is rare in parasitic flatworms and is a robust synapomorphy for schistosome spp. that exhibit it. The schistosomatid phylogeny casts some doubt on the origin of Schistosoma (Asian or African), highlights the propensity for species to hosts witch amongst mammalian (definitive) hosts, and indicates the likely importance of snail (intermediate)hosts in determining and defining patterns of schistosome radiation and continental invasion. Mitogenomic sampling of Schistosoma dattai and Schistosoma harinasutai to determine gene order, and within key species, especially S. turkestanicum and S. incognitum, to determine ancestral ranges, may help discover the geographic origins of gene order change in the genus. Samples of S. incognitum from India and Thailand suggest this taxon may include cryptic species. PMID:23362512

  20. Caryophyllidean tapeworms (Platyhelminthes: Eucestoda) from freshwater fishes in Japan.

    PubMed

    Scholz, T; Shimazu, T; Olson, P D; Nagasawa, K

    2001-01-01

    The following caryophyllidean tapeworms were found in freshwater fishes from Japan (species reported from Japan for the first time marked with an asterisk): family Caryophyllaeidae: Paracaryophyllaeus gotoi (Motomura, 1927) from Misgurnus anguillicaudatus (Cantor); Archigetes sieboldi Leuckart, 1878 from Pseudorasbora parva (Temminck et Schlegel) and Sarcocheilichthys variegatus microoculus Mori (new hosts); family Lytocestidae: *Caryophyllaeides ergensi Scholz, 1990 from Tribolodon hakuensis (Günther), T. ezoe Okada et Ikeda, Hemibarbus barbus (Temminck et Schlegel) and Chaenogobius sp. (new hosts); Khawia japonensis (Yamaguti, 1934) from Cyprinus carpio Linnaeus; K. sinensis Hsü, 1935 from H. barbus (new host) and C. carpio; *K. parva (Zmeev, 1936) from Carassius auratus langsdorfii Valenciennes in Cuvier et Valenciennes and Carassius sp. (new hosts); and *Atractolytocestus sagittatus (Kulakovskaya et Akhmerov, 1962) from C. carpio; family Capingentidae: *Breviscolex orientalis Kulakovskaya, 1962 from H. barbus (new host); and Caryophyllidea gen. sp. (probably Breviscolex orientalis) from C. carpio. The validity of C. ergensi, originally described from Leuciscus leuciscus baicalensis from Mongolia, is confirmed on the basis of an evaluation of extensive material from Japan. Atractolytocestus sagittatus (syn. Markevitschia sagittata) is tentatively considered a valid species, differing from the only congener, A. huronensis Anthony, 1958, in its considerably greater number of testes. PMID:11817451

  1. Checklist of tapeworms (Platyhelminthes, Cestoda) of vertebrates in Finland

    PubMed Central

    Haukisalmi, Voitto

    2015-01-01

    Abstract A checklist of tapeworms (Cestoda) of vertebrates (fishes, birds and mammals) in Finland is presented, based on published observations, specimens deposited in the collections of the Finnish Museum of Natural History (Helsinki) and the Zoological Museum of the University of Turku, and additional specimens identified by the present author. The checklist includes 170 tapeworm species from 151 host species, comprising 447 parasite species/host species combinations. Thirty of the tapeworm species and 96 of the parasite/host species combinations have not been previously reported from Finland. The total number of tapeworm species in Finland (170 spp.) is significantly lower than the corresponding figure for the Iberian Peninsula (257 spp.), Slovakia (225 spp.) and Poland (279 spp.). The difference between Finland and the other three regions is particularly pronounced for anseriform, podicipediform, charadriiform and passeriform birds, reflecting inadequate and/or biased sampling of these birds in Finland. It is predicted that there are actually ca. 270 species of tapeworms in Finland, assuming that true number of bird tapeworms in Finland corresponds to that in other European countries with more comprehensive knowledge of the local tapeworm fauna. The other main pattern emerging from the present data is the seemingly unexplained absence in (northern) Fennoscandia of several mammalian tapeworms that otherwise have extensive distributions in the Holarctic region or in Eurasia, including the northern regions. Previously unknown type specimens, that is, the holotype of Bothrimonus nylandicus Schneider, 1902 (a junior synonym of Diplocotyle olrikii Krabbe, 1874) (MZH 127096) and the syntypes of Caryophyllaeides fennica (Schneider, 1902) (MZH 127097) were located in the collections of the Finnish Museum of Natural History. PMID:26668540

  2. Spatial irregularities of sensitivity along the organ of Corti of the cochlea.

    PubMed

    Temchin, Andrei N; Ruggero, Mario A

    2014-08-20

    Fine structures of spatial profiles were computed from existing records of cat and chinchilla auditory-nerve fibers on the basis of their characteristic frequencies and cochlear maps. The spatial fine structures of characteristic-frequency thresholds and of "spontaneous" and driven firing rates were mutually correlated, implying the presence of sensitivity fluctuations due to spatial irregularities of presynaptic structures or processes of the inner hair cells and their input. These findings suggest that activity that appears spontaneous is not actually spontaneous and may indicate irregularities of tonotopic mapping in cochlear mechanics. PMID:25143615

  3. A novel organ of corti explant model for the study of cochlear implantation trauma.

    PubMed

    Bas, Esperanza; Gupta, Chhavi; Van De Water, Thomas R

    2012-11-01

    This study presents a novel in vitro model of electrode insertion trauma-induced hair cell (HC) damage and loss and its application for testing the efficacy of otoprotective drugs. In the cochlear implant (CI) procedure as a treatment for profound deafness, an electrode array is surgically inserted to provide electrical stimulation to the auditory nerve. Mechanical trauma from insertion of a CI electrode into the scala tympani can lead to inflammation and a high level of oxidative stress, which can initiate the apoptosis of auditory HCs and intracochlear fibrosis. HC apoptosis and intracochlear fibrosis are thought to be causes of poor CI functional outcomes. In order to gain insight into the molecular mechanisms that initiate HC apoptosis and scala tympani fibrosis following electrode insertion trauma (EIT), and the otoprotective effects of dexamethasone (DXM) observed in previous studies, an in vitro model of EIT was designed. Here we present and characterize a novel, reproducible in vitro model for the study of cellular and molecular events that occur following an EIT procedure. Cochleae from 3-day-old rats were subjected to a cochleostomy and were then divided into three groups: (1) control, (2) EIT, and (3) EIT + DXM (20 μg/mL). In Groups 2 and 3, a 0.28-mm diameter monofilament fishing line was introduced through the small cochleostomy located next to the round window area, allowing for an insertion of between 110° and 150°. HC counts, gene expression for pro-inflammatory cytokines (i.e., TNFα and IL-1β), pro-inflammatory inducible enzymes (i.e., iNOS and COX-2) and growth factors (i.e., TGFβ1, TGFβ3 and CTGF), oxidative stress (i.e., CellROX), and analyses of apoptosis pathways (i.e., caspase-3, apoptosis induced factor and Endonuclease G) were carried out on all explants at different time points. The results of this EIT in vitro model show the initiation of wound healing in which an inflammatory response is followed by a proliferative-fibrosis phase. Moreover, DXM treatment of EIT explants inhibited the inflammatory response and promoted a nonscarring wound healing process. The novel in vitro model described here will improve our understanding of mechanisms underlying CI insertion trauma and protective strategies such as DXM treatment. PMID:23044812

  4. Insight into the role of cetaceans in the life cycle of the tetraphyllideans (Platyhelminthes: Cestoda).

    PubMed

    Aznar, F J; Agustí, C; Littlewood, D T J; Raga, J A; Olson, P D

    2007-02-01

    Four types of tetraphyllidean larvae infect cetaceans worldwide: two plerocercoids differing in size, 'small' (SP) and 'large' (LP), and two merocercoids referred to as Phyllobothrium delphini and Monorygma grimaldii. The latter merocercoid larvae parasitize marine mammals exclusively and exhibit a specialised cystic structure. Adult stages are unknown for any of the larvae and thus the role of cetaceans in the life cycle of these species has been a long-standing problem. The SP and LP forms are thought to be earlier stages of P. delphini and M. grimaldii that are presumed to infect large pelagic sharks that feed on cetaceans. A molecular analysis of the D2 variable region of the large subunit ribosomal DNA gene based on several individuals of each larval type collected from three Mediterranean species of cetaceans showed consistent and unique molecular signatures for each type regardless of host species or site of infection. The degree of divergence suggested that LP, P. delphini and M. grimaldii larvae may represent separate species, whereas SP may be conspecific with M. grimaldii. In all host species, individuals of SP accumulated in the gut areas in which the lymphoid tissue was especially developed. We suggest therefore that these larvae use the lymphatic system to migrate to the abdominal peritoneum and mesenteries where they develop into forms recognizable as M. grimaldii. The plerocercoid stage of P. delphini remains unknown. In a partial phylogenetic tree of the Tetraphyllidea, all larvae formed a clade that included a representative of the genus Clistobothrium, some species of which parasitize sharks such as the great white which is known to feed on cetaceans. A bibliographic examination of tetraphyllidean infections in marine mammals indicated that these larvae are acquired mostly offshore. In summary, the evidence suggests that cetaceans play a significant role in the life cycle of these larvae. In addition, it seems clear that cetaceans act as natural intermediate hosts for P. delphini and M. grimaldii, as within these hosts they undergo development from the plerocercoid stage to the merocercoid stage. Because tetraphyllidean species use fish, cephalopods and other marine invertebrates as intermediate hosts, the inclusion of cetaceans in the life cycle would have facilitated their transmission to apex predators such as the large, lamnid sharks. The biological significance of infections of LP in cetaceans is unclear, but infections do not seem to be accidental as such larvae show high prevalence and abundance as well as a high degree of site specificity, particularly in the anal crypts and bile ducts. PMID:17161403

  5. Molecular phylogeny and systematics of the Echinostomatoidea Looss, 1899 (Platyhelminthes: Digenea).

    PubMed

    Tkach, Vasyl V; Kudlai, Olena; Kostadinova, Aneta

    2016-03-01

    The Echinostomatoidea is a large, cosmopolitan group of digeneans currently including nine families and 105 genera, the vast majority parasitic, as adults, in birds with relatively few taxa parasitising mammals, reptiles and, exceptionally, fish. Despite the complex structure, diverse content and substantial species richness of the group, almost no attempt has been made to elucidate its phylogenetic relationships at the suprageneric level based on molecules due to the lack of data. Herein, we evaluate the consistency of the present morphology-based classification system of the Echinostomatoidea with the phylogenetic relationships of its members based on partial sequences of the nuclear lsrRNA gene for a broad diversity of taxa (80 species, representing eight families and 40 genera), including representatives of five subfamilies of the Echinostomatidae, which currently exhibits the most complex taxonomic structure within the superfamily. This first comprehensive phylogeny for the Echinostomatoidea challenged the current systematic framework based on comparative morphology. A morphology-based evaluation of this new molecular framework resulted in a number of systematic and nomenclatural changes consistent with the phylogenetic estimates of the generic and suprageneric boundaries and a new phylogeny-based classification of the Echinostomatoidea. In the current systematic treatment: (i) the rank of two family level lineages, the former Himasthlinae and Echinochasminae, is elevated to full family status; (ii) Caballerotrema is distinguished at the family level; (iii) the content and diagnosis of the Echinostomatidae (sensu stricto) (s. str.) are revised to reflect its phylogeny, resulting in the abolition of the Nephrostominae and Chaunocephalinae as synonyms of the Echinostomatidae (s. str.); (iv) Artyfechinostomum, Cathaemasia, Rhopalias and Ribeiroia are re-allocated within the Echinostomatidae (s. str.), resulting in the abolition of the Cathaemasiidae, Rhopaliidae and Ribeiroiinae, which become synonyms of the Echinostomatidae (s. str.); and (v) refinements of the generic boundaries within the Echinostomatidae (s. str.), Psilostomidae and Fasciolidae are made. PMID:26699402

  6. Comparative Genomics of Flatworms (Platyhelminthes) Reveals Shared Genomic Features of Ecto- and Endoparastic Neodermata

    PubMed Central

    Hahn, Christoph; Fromm, Bastian; Bachmann, Lutz

    2014-01-01

    The ectoparasitic Monogenea comprise a major part of the obligate parasitic flatworm diversity. Although genomic adaptations to parasitism have been studied in the endoparasitic tapeworms (Cestoda) and flukes (Trematoda), no representative of the Monogenea has been investigated yet. We present the high-quality draft genome of Gyrodactylus salaris, an economically important monogenean ectoparasite of wild Atlantic salmon (Salmo salar). A total of 15,488 gene models were identified, of which 7,102 were functionally annotated. The controversial phylogenetic relationships within the obligate parasitic Neodermata were resolved in a phylogenomic analysis using 1,719 gene models (alignment length of >500,000 amino acids) for a set of 16 metazoan taxa. The Monogenea were found basal to the Cestoda and Trematoda, which implies ectoparasitism being plesiomorphic within the Neodermata and strongly supports a common origin of complex life cycles. Comparative analysis of seven parasitic flatworm genomes identified shared genomic features for the ecto- and endoparasitic lineages, such as a substantial reduction of the core bilaterian gene complement, including the homeodomain-containing genes, and a loss of the piwi and vasa genes, which are considered essential for animal development. Furthermore, the shared loss of functional fatty acid biosynthesis pathways and the absence of peroxisomes, the latter organelles presumed ubiquitous in eukaryotes except for parasitic protozoans, were inferred. The draft genome of G. salaris opens for future in-depth analyses of pathogenicity and host specificity of poorly characterized G. salaris strains, and will enhance studies addressing the genomics of host–parasite interactions and speciation in the highly diverse monogenean flatworms. PMID:24732282

  7. First records of Cotylea (Polycladida, Platyhelminthes) for the Atlantic coast of the Iberian Peninsula.

    PubMed

    Noreña, Carolina; Marquina, Daniel; Perez, Jacinto; Almon, Bruno

    2014-01-01

    A study of polyclad fauna of the Atlantic coast of the Iberian Peninsula was carried out from 2010 to 2013. The paper reports nine new records belonging to three Cotylean families: the family Euryleptidae Lang, 1884, Pseudocerotidae Lang, 1884 and the family Prosthiostomidae Lang, 1884, and describes one new species, Euryleptodes galikias sp. n. PMID:24843268

  8. First records of Cotylea (Polycladida, Platyhelminthes) for the Atlantic coast of the Iberian Peninsula

    PubMed Central

    Noreña, Carolina; Marquina, Daniel; Perez, Jacinto; Almon, Bruno

    2014-01-01

    Abstract A study of polyclad fauna of the Atlantic coast of the Iberian Peninsula was carried out from 2010 to 2013. The paper reports nine new records belonging to three Cotylean families: the family Euryleptidae Lang, 1884, Pseudocerotidae Lang, 1884 and the family Prosthiostomidae Lang, 1884, and describes one new species, Euryleptodes galikias sp. n. PMID:24843268

  9. Monorchiids (Platyhelminthes: Digenea) of chaetodontid fishes (Perciformes): biogeographical patterns in the tropical Indo-West Pacific.

    PubMed

    McNamara, M K A; Adlard, R D; Bray, R A; Sasal, P; Cribb, T H

    2012-06-01

    Species richness and biogeography of the monorchiid genus Hurleytrematoides was studied by the examination of 2834 individuals of 45 species of Chaetodontidae at six major sites in the tropical Indo-West Pacific: Heron Island, Lizard Island, Ningaloo (Western Australia), Palau, New Caledonia and Moorea (French Polynesia). In total, 18 species were distributed among six sites; descriptions are provided for eight new species: H. boucheti n. sp., H. combesi n. sp., H. deblocki n. sp., H. dollfusi n. sp., H. euzeti n. sp., H. kulbickii n. sp., H. pasteuri n. sp., and H. planesi n. sp. Overall richness ranged from zero to five Hurleytrematoides species per chaetodontid species. Seven Hurleytrematoides species were found at only one locality and eleven were found at multiple localities. Only one species, H. morandi, was found at all localities. Individual localities had between six (Moorea) and 10 (Heron Island) species; we attribute Moorea's depauperate parasite fauna to its isolation and distance from the Indo-Philippine centre of biological diversity. Using cluster analysis of 18 species of Hurleytrematoides and 45 species of chaetodontids sampled in the Indo-West Pacific, we show that the localities on the Great Barrier Reef (Heron Island and Lizard Island) and New Caledonia have the most similar chaetodontid and parasite fauna of any locality pairs. Cluster analysis results also show that the similarity of the chaetodontid assemblages at five of the six localities is relatively high and that Ningaloo has the most distinct fauna. Similarity values based on sharing of species of Hurleytrematoides are generally lower than those for their hosts; Moorea, Ningaloo and Palau all have low similarity to New Caledonia and Great Barrier Reef sites. We attribute these distinctions to the differential dispersal capability of the fish and their parasites. Chaetodontids have long-lived mobile pelagic larvae, the dispersal of which would be most affected by prominent biogeographical barriers, such as that between the Indian and Pacific Oceans. In contrast, monorchiids have no obvious dispersal stage, and vast distances have the capacity to act as effective barriers to dispersal. We conclude that the present distributions of species of Hurleytrematoides in the Indo-Pacific are driven by historical opportunity and capacity to disperse, and that some disjunct distributions are sculpted by stochasticity. PMID:22154425

  10. Fine-scale differences in diel activity among nocturnal freshwater planarias (Platyhelminthes: Tricladida)

    PubMed Central

    2011-01-01

    Background Although most freshwater planarias are well known photonegative organisms, their diel rhythms have never been quantified. Differences in daily activity rhythms may be particularly important for temperate-climate, freshwater planarias, which tend to overlap considerably in spatial distribution and trophic requirements. Methods Activity of stress-free, individually tested young adults of three common planarian species was recorded at 3-h intervals in a 10-d experiment under natural sunlight and photoperiod during autumnal equinox (D:L ~12:12). Individual activity status was averaged over the 10-d experiment, each tested individual thus serving as a true replicate. Twelve individuals per species were tested. Food was provided every 36 h, resulting in alternating day- and nighttime feeding events. Activity during the first post-feeding h was recorded and analyzed separately. Statistical procedures included ANOVAs, correlations, and second-order analyses of angles. Results Dugesia (= Girardia) tigrina Girard 1850 exhibited clear nocturnal behavior, Dugesia (= Schmidtea) polychroa Schmidt 1861 was predominantly but not exclusively nocturnal, and Polycelis tenuis Ijima 1884 was relatively more active from midnight through noon. Species-specific activity peaks were statistically similar, with peaks at dawn for P. tenuis and just before midnight for the two dugesiids; however, D. tigrina was comparatively more active in the early night hours, while D. polychroa was more active than D. tigrina during daytime. D. tigrina also responded less readily to daytime food addition. P. tenuis remained poorly active and unresponsive throughout the experiment. Individual variability in diel behavior was highest for D. polychroa and lowest for D. tigrina. P. tenuis's general low degree of activity and late activity peak in the experiment may be related to a strong reliance on external stimuli. Conclusions The tested species are mainly nocturnal, consistent with their photonegative characteristics. The fine-scale differences in diel behavior among these three triclad species may not be sufficient to allow coexistence in the wild, with the nonnative D. tigrina eventually displacing D. polychroa and P. tenuis in many European waters. The link between planarian diel rhythms and ecological characteristics are worth of further, detailed investigation. PMID:21477354

  11. First report of the land planarian Diversibipalium multilineatum (Makino & Shirasawa, 1983) (Platyhelminthes, Tricladida, Continenticola) in Europe.

    PubMed

    Mazza, Giuseppe; Menchetti, Mattia; Sluys, Ronald; Solà, Eduard; Riutort, Marta; Tricarico, Elena; Justine, Jean-Lou; Cavigioli, Luca; Mori, Emiliano

    2016-01-01

    Introduction of alien species may significantly affect soil ecosystems, through predation or disruption of components of native ecosystems (Winsor et al. 2004; Álvarez-Presas et al. 2014; Justine et al. 2014). Land planarians have been reported as alien species in soils throughout the world and, among those, some species are considered to be successful invaders, e.g. Platydemus manokwari de Beauchamp, 1963, Arthurdendyus triangulatus (Dendy, 1894), Bipalium adventitium Hyman, 1943, Bipalium kewense Moseley, 1878 and Dolichoplana striata Moseley, 1877 (Winsor et al. 2004; Álvarez-Presas et al. 2014; Justine et al. 2014, 2015). Soil moisture status seems to be an important element for their successful invasion (Fraser & Boag 1998). In Europe at least 18 species of alien land planarians have been recorded since now and some of them are considered as invasive ones, e.g. P. manokwari (cf. Justine et al. 2014). Although the alien land planarian B. kewense has been reported to occur in many greenhouses in Italy (Bello et al. 1995), no data are available on its establishment and/or impact on natural environments. On 28th September 2014, 20 specimens (~1 individual/m2) of the land planarian Diversibipalium multilineatum (Makino & Shirasawa, 1983) (Fig. 1), native to Japan, were collected under pots, branches and plastic materials in a private garden located in the center of Bologna (Emilia Romagna, Central Italy), near the urban park Giardini Margherita (44°29' N, 11°21' E; WGS84). Thirty plant species (both indigenous and alien), mainly cultivated as bonsai (e.g. Lagerstroemia indica L., Juniperus procumbens (Siebold ex Endl.) Miquel), were present in this shady, wet garden (25 m2). Between March 2014 and June 2015, 70 more specimens of D. multilineatum were collected at the same site, mainly at dusk and dawn after rain. Reproduction by fission and regeneration processes were observed in several of those specimens, which were kept for some time in captivity. A specimen of D. multilineatum was also collected in a garden in Léguevin (Haute-Garonne, France), which will be described in a forthcoming paper by Justine et al. (in prep.) (see also Kawakatsu et al. 2014). Specimens without a genital pore were initially ascribed to D. multilineatum on the basis of their external appearance: the dorsal surface was brownish yellow and presented five longitudinal stripes at the head plate and the neck, showing the typical appearance of the species. The middorsal stripe was widened at its anterior end, on the head plate, and at the pharynx level. The ventral pattern of the animals at the pharyngeal region was also characteristic, with the middorsal stripe widened at this level. The Italian Diversibipalium specimens used for the molecular analysis were fixed and preserved in absolute ethanol. Fragments of the mitochondrial gene COI and 28S ribosomal RNA nuclear gene (GenBank Acc. Numbers KU245358 and KU245357, respectively) were obtained using the procedure and COI primers described in Álvarez-Presas et al. (2008) and Solà et al. (2013). The French specimen's COI (Specimen MNHN JL177, GenBank Acc. Number KT922162) was obtained as described in Justine et al. (2015). 28S sequences of 14 Bipaliinae specimens and four Microplana species (outgroup) retrieved from GenBank were included in the phylogenetic analyses (Fig. 2). Sequence alignment was obtained by using the online software MAFFT version 7 (Katoh & Standley 2013), while ambiguously aligned positions were removed using the program Gblocks (Talavera & Castresana 2007) with default settings, excepting the minimum number of sequences for a flank position at the minimum value (set at 10) and with half of the allowed gap positions. The final alignment had a length of 1589 bp. We used two phylogenetic inference approaches: maximum likelihood (ML), using the RaxML 8.2.3 software (Stamatakis 2014), and Bayesian inferences (BI), using MrBayes 3.2.4 (Ronquist et al. 2012). The evolutionary model used, GTR+I+G, was estimated t

  12. Description of a New Temnocephala Species (Platyhelminthes) from the Southern Neotropical Region.

    PubMed

    de León, Rodrigo Ponce; Vera, Bárbara Berón; Volonterio, Odile

    2015-08-01

    The genus Temnocephala is endemic to the Neotropical region. Temnocephala mexicana and Temnocephala chilensis are the only 2 temnocephalans whose known distribution ranges extend to the south beyond Parallel 40°S. No Temnocephala species has ever been recorded from the extensive area between Parallel 43°S and the southern end of the South American continent, which makes the study of the southern limit of the distribution of the genus a topic of great interest. The southernmost report corresponds to T. chilensis from the Telsen River, Chubut Province, Argentina. In March 2000, several temnocephalans were found on the freshwater anomuran crustacean Aegla neuquensis from the same locality; the specimens were identified as belonging to a new species, which is described here. This species is characterized by possessing an unusually thin-walled, narrow zone that has the appearance of a deep groove connecting the introvert to the shaft of the penial stylet; an introvert with 36 longitudinal rows of spines, each bearing 6-8 spines that are progressively smaller towards the distal end; a distal end of the introvert with a very thin, sclerotized wall without spines; a seminal vesicle that opens sub-polarly into the contractile vesicle; a pair of paranephrocytes at the level of the pharynx and a second pair at the level of the anterior portion of the anterior testes, and eggs with very long stalks. On the basis of their overall morphology, host preference, and geographical distribution, T. chilensis and the new species are closely related, so a diagnostic key for the southern species of Temnocephala is also included. The type locality of the new species is in the southern limit of the known distribution area of T. chilensis, so after this work there are 2 known species marking the southern limit of the distribution of the genus. PMID:25871978

  13. Molecular characterization of Gastrodiscoides hominis (Platyhelminthes: Trematoda: Digenea) inferred from ITS rDNA sequence analysis.

    PubMed

    Goswami, L M; Prasad, P K; Tandon, V; Chatterjee, A

    2009-06-01

    Gastrodiscoides hominis (Digenea: Paramphistomata: Gastrodiscidae) is an amphistomid intestinal fluke of pigs causing gastrodiscoidiosis. With the use of molecular tools assisting the conventional diagnostic procedures, we aimed at finding out molecular characterization of G. hominis using PCR amplifications of rDNA ITS (1, 2) sequences. The sequences obtained (GenBank accession numbers EF027096, EF027097, EF027098, EU887294, and EU887295) were compared with available sequences of other digenean parasites, particularly those having a zoonotic potential in the northeastern region of India. The BLAST search revealed a close similarity with members of the family Paramphistomidae, showing maximum similarity with the amphistome, Homalogaster paloniae (subfamily Paramphistominae). Based on various tree construction methods, phylogeny of G. hominis is discussed. PMID:19198879

  14. Prey-tracking behavior in the invasive terrestrial planarian Platydemus manokwari (Platyhelminthes, Tricladida)

    NASA Astrophysics Data System (ADS)

    Iwai, Noriko; Sugiura, Shinji; Chiba, Satoshi

    2010-11-01

    Platydemus manokwari is a broadly distributed invasive terrestrial flatworm that preys heavily on land snails and has been credited with the demise of numerous threatened island faunas. We examined whether P. manokwari tracks the mucus trails of land snail prey, investigated its ability to determine trail direction, and evaluated prey preference among various land snail species. A plastic treatment plate with the mucus trail of a single species and a control plate without the trail were placed side by side at the exit of cages housing P. manokwari. All trials were then videotaped overnight. The flatworms moved along plates with mucus trails, but did not respond to plates without trails, blank control (distilled water), or with conspecific flatworm trails. When presented at the midpoint of a snail mucus trail, the flatworms followed the trail in a random direction. The flatworms showed a preference when choosing between two plates, each with a mucus trail of different land snail species. Our results suggest that P. manokwari follows snail mucus trails based on chemical cues to increase the chance of encountering prey; however, trail-tracking behavior showed no directionality.

  15. Land flatworms of the genus Pasipha (Platyhelminthes, Geoplanidae) in Argentina, with description of three new species.

    PubMed

    Negrete, Lisandro; Brusa, Francisco

    2016-01-01

    The genus Pasipha Ogren & Kawakatsu, 1990 currently includes 22 species, most of them recorded in the Brazilian Atlantic Forest. Recently, Pasipha hauseri was documented in north-eastern Argentina, thus extending its distribution range. This paper reports new records of the genus Pasipha in the Interior Atlantic Forest ecoregion in Argentina, with the description of three new species: Pasipha atla sp. nov., Pasipha johnsoni sp. nov., and Pasipha mbya sp. nov. These new species exhibit similarities in internal anatomy, such as pharynx cylindrical, extrabulbar prostatic vesicle with folded walls and proximally forked, male atrium highly folded, being at least two times longer than the female atrium and with small folds in their proximal portion. However, they can be distinguished from each other mainly by the secretion types discharged into the prostatic vesicle as well as into the male and female atria. In addition, they have different colour patterns on the dorsal surface. PMID:27470715

  16. Historical analysis of the type species of the genus Trichobilharzia Skrjabin et Zakharov, 1920 (Platyhelminthes: Schistosomatidae).

    PubMed

    Aldhoun, Jitka; Kment, Petr; Horák, Petr

    2016-01-01

    Trichobilharzia Skrjabin & Zakharov, 1920 is known as the most species-rich genus of the blood fluke family Schistosomatidae. To date, more than 40 species have been described, even though validity of some of them is questionable (Horák et al. 2002). Members of the genus use various birds as final hosts, but they attract attention mostly as causative agents of hypersensitive skin reaction (cercarial dermatitis or swimmer's itch) in mammals including humans. As this is one of the. PMID:27394285

  17. Two new species of freshwater flatworms (Platyhelminthes: Tricladida: Continenticola) from South American caves.

    PubMed

    Souza, Stella; Morais, Ana Laura; Bichuette, Maria Elina; Leal-Zanchet, Ana

    2016-01-01

    The diversity of freshwater triclads in the Neotropical region is considered to be low, but extensive areas of South America remain almost unexplored. Herein we describe two cave-dwelling, new species of Girardia, one from a transition zone of the Cerrado and Caatinga phytophysiognomies and the other from the Cerrado phytophysiognomy. The species from the Cerrado-Caatinga transition is a troglobite, eyeless and whitish; the species from the Cerrado area is possibly a troglophile, since it shows heavily pigmented body and eyes. Each species is easily recognized by a unique combination of features in its external morphology and copulatory apparatus. The two new species of Girardia show a restricted distribution, even the troglophile, and occur in caves without legal protection. Therefore, they must be considered as vulnerable organisms in a conservation context. PMID:27394369

  18. Co-Speciation of the Ectoparasite Gyrodactylus teuchis (Monogenea, Platyhelminthes) and Its Salmonid Hosts

    PubMed Central

    Hahn, Christoph; Weiss, Steven J.; Stojanovski, Stojmir; Bachmann, Lutz

    2015-01-01

    Co-speciation is a fundamental concept of evolutionary biology and intuitively appealing, yet in practice hard to demonstrate as it is often blurred by other evolutionary processes. We investigate the phylogeographic history of the monogenean ectoparasites Gyrodactylus teuchis and G. truttae on European salmonids of the genus Salmo. Mitochondrial cytochrome oxidase subunit 1 and the nuclear ribosomal internal transcribed spacer 2 were sequenced for 189 Gyrodactylus individuals collected from 50 localities, distributed across most major European river systems, from the Iberian- to the Balkan Peninsula. Despite both anthropogenic and naturally caused admixture of the principal host lineages among major river basins, co-phylogenetic analyses revealed significant global congruence for host and parasite phylogenies, providing firm support for co-speciation of G. teuchis and its salmonid hosts brown trout (S. trutta) and Atlantic salmon (S. salar). The major split within G. teuchis, coinciding with the initial divergence of the hosts was dated to ~1.5 My BP, using a Bayesian framework based on an indirect calibration point obtained from the host phylogeny. The presence of G. teuchis in Europe thus predates some of the major Pleistocene glaciations. In contrast, G. truttae exhibited remarkably low intraspecific genetic diversity. Given the direct life cycle and potentially high transmission potential of gyrodactylids, this finding is interpreted as indication for a recent emergence (<60 ky BP) of G. truttae via a host-switch. Our study thus suggests that instances of two fundamentally different mechanisms of speciation (co-speciation vs. host-switching) may have occurred on the same hosts in Europe within a time span of less than 1.5 My in two gyrodactylid ectoparasite species. PMID:26080029

  19. Investigation of the ultrastructure of Dendrocoelum constrictum (Platyhelminthes, Tricladida) spermatogenesis and mature spermatozoa.

    PubMed

    Harrath, Abdel Halim; Gammoudi, Mehrez; Mansour, Lamjed; Ahmed, Mukhtar; Sirotkin, Alexander V; Al Omar, Suliman Y; Ibrahim, Khalid E; Alwasel, Saleh H

    2014-09-01

    To add to our understanding of dendrocoelid spermatozoa and to describe additional phylogenetic characters, the ultrastructure of the testis was investigated in the subterranean freshwater planarian Dendrocoelum constrictum. This is the first study investigating spermatogenesis and spermatozoon ultrastructure in a subterranean freshwater planarian species. We found that the basic structure of spermatozoa in D. constrictum is similar to that of other Tricladida that have been studied previously. In fact, D. constrictum spermatozoa possess an elongated nucleus, one giant mitochondrion, and two subterminal flagella with a 9+'1' pattern. The flagella emerge together from one side of the spermatozoon. However, D. constrictum has some characteristics that have not yet been described for other freshwater planarians. In fact, the number of cortical microtubules reaches the maximum number in the anterior and middle part of region I, and then decrease until they disappear towards the posterior extremity of the spermatozoon. The extreme tip of the anterior region of the spermatozoon exhibits a specific external ornamentation of the plasma membrane. PMID:25242690

  20. Histological and histochemical aspects of the penial glands of Girardia biapertura Sluys, 1997 (Platyhelminthes, Tricladida, Paludicola).

    PubMed

    Souza, S T; Leal-Zanchet, A M

    2002-08-01

    Girardia biapertura was described with sperm ducts penetrating the penis bulb, subsequently opening separately at the tip of the penis papilla and receiving the abundant secretion of penial glands. In the present work, the penial glands of this species have been histologically and histochemically analysed, and four types of secretory cells are distinguished. The openings of the penial glands into the intrabulbar and intrapapillar sperm ducts, designated here as intrapenial ducts, allow for the distinction between three histologically differentiated regions. The most proximal region possibly corresponds to the bulbar cavity of other freshwater triclads whereas the median and distal portions correspond to the ejaculatory duct. The proximal region of the intrapenial ducts receives mainly the openings of a secretory cell type (type I) that produces a proteinaceous secretion. A second type of secretory cell (type II) that secretes neutral mucopolyssacharides opens into the median region of the intrapenial ducts. The distal portion of the ducts receives two types of secretory cells (types III and IV) which secret glycoprotein and glycosaminoglycans, respectively. Types III and IV open also directly into the male atrium through the epithelium of the penis papilla. A comparison with the results presented here and those of other authors for species of Girardia is provided and the importance of the study of the penial glands for taxonomic characterisation of freshwater triclads is emphasised. PMID:12530192

  1. Dugesia sicula (Platyhelminthes, Tricladida): the colonizing success of an asexual Planarian

    PubMed Central

    2013-01-01

    Background Dugesia sicula is the only species of its genus not presenting an endemic or restricted distribution within the Mediterranean area. It mostly comprises fissiparous populations (asexual reproduction by body division and regeneration), most likely sexually sterile, and characterized by an extremely low genetic diversity interpreted as the consequence of a recent anthropic expansion. However, its fissiparous reproduction can result in an apparent lack of diversity within the species, since genetic variation within individuals can be as large as between them because most individuals within a population are clones. We have estimated haplotype and nucleotide diversity of cytochrome oxidase I within and among individuals along the species distribution of a broad sample of D. sicula, including asexual and the two only sexual populations known today; and predicted its potential distribution based on climatic variables. Our aim was to determine the centre of colonisation origin, whether the populations are recent, and whether the species is expanding. Results The species presents 3 most frequent haplotypes, differing in a maximum of 11 base pairs. As expected from their fissiparous mode of reproduction, in half of all the analysed localities many individuals have multiple heteroplasmic haplotypes. The distribution of haplotypes is not geographically structured; however, the distribution of haplotypes and heteroplasmic populations shows higher diversity in the central Mediterranean region. The potential distribution predicted by climatic variables based modelling shows a preference for coastal areas and fits well with the observed data. Conclusions The distribution and frequency of the most frequent haplotypes and the presence of heteroplasmic individuals allow us to gain an understanding of the recent history of the species, together with previous knowledge on its phylogenetic relationships and age: The species most probably originated in Africa and dispersed through the central Mediterranean. After one or multiple populations became triploid and fissiparous, the species colonized the Mediterranean basin, likely both by its own means and helped by human activities. Its present distribution practically fulfils its potential distribution as modelled with climatic variables. Its prevalence in coastal regions with higher water temperatures predicts a likely future expansion to northern and more interior areas following the increase in temperatures due to climate change. PMID:24330464

  2. Three new species of freshwater Macrostomum (Platyhelminthes, Macrostomida) from southern China.

    PubMed

    Sun, Ting; Zhang, Lv; Wang, An-Tai; Zhang, Yu

    2015-01-01

    Macrostomum is a diverse genus of turbellarians with more than 180 species described from around the world. However, the Macrostomum fauna in China is poorly known. In this study, three new species of freshwater Macrostomum were described from southern China based on morphology of the penis stylet, an important character for species identification in this genus. In M. heyuanensis n. sp., the penis stylet bends 108° leftwards at its 1/2 length then backwards besides the distal opening, and the terminal region is thicker than other parts of penis stylet. In M. dongyuanensis n. sp., the penis stylet is J-shaped, with the opening at the tail end. In M. bicaudatum n. sp., the penis stylet is C-shaped, with the upper margin of the distal end longer but slimmer than the lower margin. In addition, molecular phylogenetic analyses were conducted to aid the classification of the novel species. Finally, their habitat and taxonomic status are compared and discussed. PMID:26623848

  3. First documentation and molecular confirmation of three trematode species (Platyhelminthes: Trematoda) infecting the polychaete Marenzelleria viridis (Annelida: Spionidae).

    PubMed

    Phelan, Krystin; Blakeslee, April M H; Krause, Maureen; Williams, Jason D

    2016-01-01

    Polychaete worms are hosts to a wide range of marine parasites; yet, studies on trematodes using these ecologically important species as intermediate hosts are lacking. During examination of the spionid polychaete Marenzelleria viridis collected on the north shore of Long Island, New York, putative trematode cysts were discovered in the body cavity of these polychaetes. In order to verify these cysts as metacercariae of trematodes, specimens of the eastern mudsnail Ilyanassa obsoleta (a very common first intermediate host of trematodes in the region) were collected for molecular comparison. DNA barcoding using cytochrome C oxidase I regions confirmed the presence of three species of trematodes (Himasthla quissetensis, Lepocreadium setiferoides, and Zoogonus lasius) in both M. viridis and I. obsoleta hosts. Brown bodies were also recovered from polychaetes, and molecular testing confirmed the presence of L. setiferoides and Z. lasius, indicating an immune response of the polychaete leading to encapsulation of the cysts. From the 125 specimens of M. viridis collected in 2014, 95 (76.8 %) were infected with trematodes; of these 95 infected polychaetes, 86 (90.5 %) contained brown bodies. This is the first confirmation that trematodes use M. viridis as a second intermediate host and that this intermediate host demonstrates a clear immune response to metacercarial infection. Future research should explore the role of these polychaetes in trematode life cycles, the effectiveness of the immune response, and transmission pathways to vertebrate definitive hosts. PMID:26385466

  4. The invasive land planarian Platydemus manokwari (Platyhelminthes, Geoplanidae): records from six new localities, including the first in the USA.

    PubMed

    Justine, Jean-Lou; Winsor, Leigh; Barrière, Patrick; Fanai, Crispus; Gey, Delphine; Han, Andrew Wee Kien; La Quay-Velázquez, Giomara; Lee, Benjamin Paul Yi-Hann; Lefevre, Jean-Marc; Meyer, Jean-Yves; Philippart, David; Robinson, David G; Thévenot, Jessica; Tsatsia, Francis

    2015-01-01

    The land planarian Platydemus manokwari de Beauchamp, 1963 or "New Guinea flatworm" is a highly invasive species, mainly in the Pacific area, and recently in Europe (France). We report specimens from six additional countries and territories: New Caledonia (including mainland and two of the Loyalty Islands, Lifou and Maré), Wallis and Futuna Islands, Singapore, Solomon Islands, Puerto Rico, and Florida, USA. We analysed the COI gene (barcoding) in these specimens with two sets of primers and obtained 909 bp long sequences. In addition, specimens collected in Townsville (Australia) were also sequenced. Two haplotypes of the COI sequence, differing by 3.7%, were detected: the "World haplotype" found in France, New Caledonia, French Polynesia, Singapore, Florida and Puerto Rico; and the "Australian haplotype" found in Australia. The only locality with both haplotypes was in the Solomon Islands. The country of origin of Platydemus manokwari is New Guinea, and Australia and the Solomon Islands are the countries closest to New Guinea from which we had specimens. These results suggest that two haplotypes exist in the area of origin of the species, but that only one of the two haplotypes (the "World haplotype") has, through human agency, been widely dispersed. However, since P. manokwari is now recorded from 22 countries in the world and we have genetic information from only 8 of these, with none from New Guinea, this analysis provides only partial knowledge of the genetic structure of the invasive species. Morphological analysis of specimens from both haplotypes has shown some differences in ratio of the genital structures but did not allow us to interpret the haplotypes as different species. The new reports from Florida and Puerto Rico are firsts for the USA, for the American continent, and the Caribbean. P. manokwari is a known threat for endemic terrestrial molluscs and its presence is a matter of concern. While most of the infected territories reported until now were islands, the newly reported presence of the species in mainland US in Florida should be considered a potential major threat to the whole US and even the Americas. PMID:26131377

  5. A Comprehensive Molecular Phylogeny of Dalytyphloplanida (Platyhelminthes: Rhabdocoela) Reveals Multiple Escapes from the Marine Environment and Origins of Symbiotic Relationships

    PubMed Central

    Van Steenkiste, Niels; Tessens, Bart; Willems, Wim; Backeljau, Thierry; Jondelius, Ulf; Artois, Tom

    2013-01-01

    In this study we elaborate the phylogeny of Dalytyphloplanida based on complete 18S rDNA (156 sequences) and partial 28S rDNA (125 sequences), using a Maximum Likelihood and a Bayesian Inference approach, in order to investigate the origin of a limnic or limnoterrestrial and of a symbiotic lifestyle in this large group of rhabditophoran flatworms. The results of our phylogenetic analyses and ancestral state reconstructions indicate that dalytyphloplanids have their origin in the marine environment and that there was one highly successful invasion of the freshwater environment, leading to a large radiation of limnic and limnoterrestrial dalytyphloplanids. This monophyletic freshwater clade, Limnotyphloplanida, comprises the taxa Dalyelliidae, Temnocephalida, and most Typhloplanidae. Temnocephalida can be considered ectosymbiotic Dalyelliidae as they are embedded within this group. Secondary returns to brackish water and marine environments occurred relatively frequently in several dalyeliid and typhloplanid taxa. Our phylogenies also show that, apart from the Limnotyphloplanida, there have been only few independent invasions of the limnic environment, and apparently these were not followed by spectacular speciation events. The distinct phylogenetic positions of the symbiotic taxa also suggest multiple origins of commensal and parasitic life strategies within Dalytyphloplanida. The previously established higher-level dalytyphloplanid clades are confirmed in our topologies, but many of the traditional families are not monophyletic. Alternative hypothesis testing constraining the monophyly of these families in the topologies and using the approximately unbiased test, also statistically rejects their monophyly. PMID:23536894

  6. Development of mitochondrial loop-mediated isothermal amplification for detection of the small liver fluke Opisthorchis viverrini (Opisthorchiidae; Trematoda; Platyhelminthes).

    PubMed

    Le, Thanh Hoa; Nguyen, Nga Thi Bich; Truong, Nam Hai; De, Nguyen Van

    2012-04-01

    Mitochondrial DNA sequences offer major advantages over the more usual nuclear targets for loop-mediated isothermal amplification approaches (mito-LAMP) because multiple copies occur in every cell. Four LAMP primers [F3, FIP(F1c+F2), BIP(B1c+B2), and B3] were designed based on the mitochondrial nad1 sequence of Opisthorchis viverrini and used for a highly specific assay (mito-OvLAMP) to distinguish DNA of O. viverrini from that of another opisthorchiid (Clonorchis sinensis) and other trematodes (Haplorchis pumilio, Haplorchis taichui, Fasciola hepatica, and Fasciola gigantica). Conventional PCR was applied using F3/B3 primer pairs to verify the specificity of the primers for O. viverrini DNA templates. All LAMP-positive samples could be detected with the naked eye in sunlight, by gel electrophoresis (stained with ethidium bromide), and by addition of SYBR green I to the product in sunlight or under UV light. Only DNA from O. viverrini yielded amplification products by LAMP (and by PCR verification), and the LAMP limit of detection was as little as 100 fg (10(-4) ng DNA), indicating that this assay is 10 to 100 times more sensitive than PCR. Field testing was done using representative egg and metacercarial samples collected from localities where the fluke is endemic. With the advantages of simplicity, rapidity, sensitivity, and cost effectiveness, mito-OvLAMP is a good tool for molecular detection and epidemiology studies in regions or countries where O. viverrini is endemic, which can lead to more effective control of opisthorchiasis and trematodiasis. PMID:22322346

  7. The invasive land planarian Platydemus manokwari (Platyhelminthes, Geoplanidae): records from six new localities, including the first in the USA

    PubMed Central

    Winsor, Leigh; Barrière, Patrick; Fanai, Crispus; Gey, Delphine; Han, Andrew Wee Kien; La Quay-Velázquez, Giomara; Lee, Benjamin Paul Yi-Hann; Lefevre, Jean-Marc; Meyer, Jean-Yves; Philippart, David; Robinson, David G.; Thévenot, Jessica; Tsatsia, Francis

    2015-01-01

    The land planarian Platydemus manokwari de Beauchamp, 1963 or “New Guinea flatworm” is a highly invasive species, mainly in the Pacific area, and recently in Europe (France). We report specimens from six additional countries and territories: New Caledonia (including mainland and two of the Loyalty Islands, Lifou and Maré), Wallis and Futuna Islands, Singapore, Solomon Islands, Puerto Rico, and Florida, USA. We analysed the COI gene (barcoding) in these specimens with two sets of primers and obtained 909 bp long sequences. In addition, specimens collected in Townsville (Australia) were also sequenced. Two haplotypes of the COI sequence, differing by 3.7%, were detected: the “World haplotype” found in France, New Caledonia, French Polynesia, Singapore, Florida and Puerto Rico; and the “Australian haplotype” found in Australia. The only locality with both haplotypes was in the Solomon Islands. The country of origin of Platydemus manokwari is New Guinea, and Australia and the Solomon Islands are the countries closest to New Guinea from which we had specimens. These results suggest that two haplotypes exist in the area of origin of the species, but that only one of the two haplotypes (the “World haplotype”) has, through human agency, been widely dispersed. However, since P. manokwari is now recorded from 22 countries in the world and we have genetic information from only 8 of these, with none from New Guinea, this analysis provides only partial knowledge of the genetic structure of the invasive species. Morphological analysis of specimens from both haplotypes has shown some differences in ratio of the genital structures but did not allow us to interpret the haplotypes as different species. The new reports from Florida and Puerto Rico are firsts for the USA, for the American continent, and the Caribbean. P. manokwari is a known threat for endemic terrestrial molluscs and its presence is a matter of concern. While most of the infected territories reported until now were islands, the newly reported presence of the species in mainland US in Florida should be considered a potential major threat to the whole US and even the Americas. PMID:26131377

  8. Spot the difference: Two cryptic species of Gyrodactylus von Nordmann, 1832 (Platyhelminthes: Monogenea) infecting Astyanax aeneus (Actinopterygii, Characidae) in Mexico.

    PubMed

    Razo-Mendivil, Ulises; García-Vásquez, Adriana; Rubio-Godoy, Miguel

    2016-10-01

    Over the course of one year, undescribed specimens of Gyrodactylus were recovered from banded tetra, Astyanax aeneus collected in the La Antigua and Nautla river basins in central Veracruz, Mexico. Parasites were processed for morphometric and molecular analyses. Morphometrically, Gyrodactylus samples collected in the La Antigua river had slightly smaller haptoral structures than those collected from the Nautla river. During the 12month-collection of samples, however, water temperature varied considerably (ca. 20°C to 30°C), and this abiotic factor is known to affect the size of gyrodactylid attachment structures. Moreover, no clear discrimination was possible between individual parasites collected from the two rivers based on the morphology of the marginal hook, which is recognised as a very informative character to discriminate between species. The morphology of the ventral bar, however, differed between specimens from both rivers: worms from Nautla all had long, rounded processes on the ventral bar, which formed a relatively closed angle with the dorsal edge of the bar proper, while most - but not all - specimens from La Antigua had comparatively slender processes forming a more open angle with respect to the ventral bar. Phylogenetic analyses based on the sequences of the ITS1, 5.8S rRNA gene, and ITS2 of gyrodactylids indicated the existence of two distinct, well-supported lineages whose sequences differ by >4%, one of which was only found in the Nautla basin, while the other was collected in both river systems. A posteriori, principal component analysis (PCA) of the morphometric data of sequenced specimens indicated that features of the dorsal bar, the hamuli and the ventral bar enable discrimination between the two phylogenetic lineages. Based on these independent sources of information (morphometric and molecular data), two new species of Gyrodactylus are described: Gyrodactyluspakan n. sp. and Gyrodactylusteken n. sp. The phylogenetic relationships of both new species to other gyrodactylids infecting characiformes (for which molecular data are available) are presented, which suggests that their closest relative is Gyrodactylus carolinae, a parasite of Characidium lanei in Brazil. PMID:27208885

  9. Cryptostylochus hullensis sp. nov. (Polycladida, Acotylea, Platyhelminthes): A possible case of transoceanic dispersal on a ship's hull

    NASA Astrophysics Data System (ADS)

    Faubel, A.; Gollasch, S.

    1996-12-01

    In July 1993, the car carrier “Faust” entered Bremerhaven after a voyage from the North-American Atlantic coast to Europe. In a dockyard, five living specimens of the order Polycladida were collected from the hull of the ship. This could be a possible case of trans-atlantic dispersal of plathelminths living as fouling organisms of ships. The specimens found represent a new species of the genus Cryptostylochus Faubel, 1983, Cryptostylochus hullensis sp. nov.

  10. A new and alien species of ``oyster leech'' (Platyhelminthes, Polycladida, Stylochidae) from the brackish North Sea Canal, The Netherlands

    NASA Astrophysics Data System (ADS)

    Sluys, Ronald; Faubel, Anno; Rajagopal, Sanjeevi; Velde, Gerard Van Der

    2005-11-01

    A new species of polyclad flatworm, Imogine necopinata Sluys, sp. nov., is described from a brackish habitat in The Netherlands. Taxonomic affinities with Asian species and the ecology of the animals suggest that the species is an introduced, exotic component of the Dutch fauna. The new species belongs to a group of worms with species that are known to predate on oysters.

  11. Fluvial basin history in the northeastern Mediterranean region underlies dispersal and speciation patterns in the genus Dugesia (Platyhelminthes, Tricladida, Dugesiidae).

    PubMed

    Solà, Eduard; Sluys, Ronald; Gritzalis, Konstantinos; Riutort, Marta

    2013-03-01

    In this study we analyzed the phylogenetic relationships of eastern Mediterranean freshwater planarians of the genus Dugesia, estimated divergence times for the various clades, and correlated their phylogeographic patterns with geological and paleoclimatic events, in order to discover which evolutionary processes have shaped the present-day distribution of these animals. Specimens were collected from freshwater courses and lakes in continental and insular Greece. Genetic divergences and phylogenetic relationships were inferred by using the mitochondrial gene subunit I of cytochrome oxidase (COI) and the nuclear ribosomal internal transcribed spacer-1 (ITS-1) from 74 newly collected individuals from Greece. Divergence time estimates were obtained under a Bayesian framework, using the COI sequences. Two alternative geological dates for the isolation of Crete from the mainland were tested as calibration points. A clear phylogeographic pattern was present for Dugesia lineages in the Eastern Mediterranean. Morphological data, combined with information on genetic divergences, revealed that eight out of the nine known species were represented in the samples, while additional new, and still undescribed species were detected. Divergence time analyses suggested that Dugesia species became isolated in Crete after the first geological isolation of the island, and that their present distribution in the Eastern Mediterranean has been shaped mainly by vicariant events but also by dispersal. During the Messinian salinity crisis these freshwater planarians apparently were not able to cross the sea barrier between Crete and the mainland, while they probably did disperse between islands in the Aegean Sea. Their dependence on freshwater to survive suggests the presence of contiguous freshwater bodies in those regions. Our results also suggest a major extinction of freshwater planarians on the Peloponnese at the end of the Pliocene, while about 2Mya ago, when the current Mediterranean climate was established, these Peloponnese populations probably began to disperse again. At the end of the Pliocene or during the Pleistocene, mainland populations of Dugesia colonized the western coast, including the Ionian Islands, which were then part of the continent. PMID:23182762

  12. First report of the exotic blue land planarian, Caenoplana coerulea (Platyhelminthes, Geoplanidae), on Menorca (Balearic Islands, Spain)

    PubMed Central

    Breugelmans, Karin; Cardona, Josep Quintana; Artois, Tom; Jordaens, Kurt; Backeljau, Thierry

    2012-01-01

    Abstract In April 2009 two specimens of a terrestrial flatworm were collected from under a rock in an orchard at Ciutadella de Menorca on the easternmost Balearic island of Menorca (Spain). Their external morphology suggested that both specimens belonged to the invasive blue planarian Caenoplana coerulea, a species which is native to eastern Australia. Sequence data of a fragment of the mitochondrial cytochrome c oxidase subunit I (COI) and of the entire 18S ribosomal RNA confirm its identification. This is one of the first records of the species in Europe where it has only been found in one locality in the United Kingdom, France and NE Spain. PMID:22711997

  13. Differential transcriptomic responses of Biomphalaria glabrata (Gastropoda, Mollusca) to bacteria and metazoan parasites, Schistosoma mansoni and Echinostoma paraensei (Digenea, Platyhelminthes).

    PubMed

    Adema, Coen M; Hanington, Patrick C; Lun, Cheng-Man; Rosenberg, George H; Aragon, Anthony D; Stout, Barbara A; Lennard Richard, Mara L; Gross, Paul S; Loker, Eric S

    2010-01-01

    A 70-mer-oligonucleotide-based microarray (1152 features) that emphasizes stress and immune responses factors was constructed to study transcriptomic responses of the snail Biomphalaria glabrata to different immune challenges. In addition to sequences with relevant putative ID and Gene Ontology (GO) annotation, the array features non-immune factors and unknown B. glabrata ESTs for functional gene discovery. The transcription profiles of B. glabrata (3 biological replicates, each a pool of 5 snails) were recorded at 12h post-wounding, exposure to Gram negative or Gram positive bacteria (Escherichia coli and Micrococcus luteus, respectively), or infection with compatible trematode parasites (Schistosoma mansoni or Echinostoma paraensei, 20 miracidia/snail), relative to controls, using universal reference RNA. The data were subjected to Significance Analysis for Microarrays (SAM), with a false positive rate (FPR)

  14. When proglottids and scoleces conflict: phylogenetic relationships and a family-level classification of the Lecanicephalidea (Platyhelminthes: Cestoda).

    PubMed

    Jensen, Kirsten; Caira, Janine N; Cielocha, Joanna J; Littlewood, D Timothy J; Waeschenbach, Andrea

    2016-05-01

    This study presents the first comprehensive phylogenetic analysis of the interrelationships of the morphologically diverse elasmobranch-hosted tapeworm order Lecanicephalidea, based on molecular sequence data. With almost half of current generic diversity having been erected or resurrected within the last decade, an apparent conflict between scolex morphology and proglottid anatomy has hampered the assignment of many of these genera to families. Maximum likelihood and Bayesian analyses of two nuclear markers (D1-D3 of lsrDNA and complete ssrDNA) and two mitochondrial markers (partial rrnL and partial cox1) for 61 lecanicephalidean species representing 22 of the 25 valid genera were conducted; new sequence data were generated for 43 species and 11 genera, including three undescribed genera. The monophyly of the order was confirmed in all but the analyses based on cox1 data alone. Sesquipedalapex placed among species of Anteropora and was thus synonymized with the latter genus. Based on analyses of the concatenated dataset, eight major groups emerged which are herein formally recognised at the familial level. Existing family names (i.e., Lecanicephalidae, Polypocephalidae, Tetragonocephalidae, and Cephalobothriidae) are maintained for four of the eight clades, and new families are proposed for the remaining four groups (Aberrapecidae n. fam., Eniochobothriidae n. fam., Paraberrapecidae n. fam., and Zanobatocestidae n. fam.). The four new families and the Tetragonocephalidae are monogeneric, while the Cephalobothriidae, Lecanicephalidae and Polypocephalidae comprise seven, eight and four genera, respectively. As a result of their unusual morphologies, the three genera not included here (i.e., Corrugatocephalum, Healyum and Quadcuspibothrium) are considered incertae sedis within the order until their familial affinities can be examined in more detail. All eight families are newly circumscribed based on morphological features and a key to the families is provided. Aspects of morphological evolution and host associations are discussed in a phylogenetic context for each family and for the order as a whole. Lecanicephalidean genera lacking apical structures were confirmed as the earliest diverging lineages. Proglottid anatomy was determined to be much more conserved and indicative of phylogenetic affinities than scolex morphology. Collectively, the Lecanicephalidea parasitize three of the four orders of Batoidea-their almost exclusive absence from skates (Order Rajiformes) appears to be real; only a few records from sharks exist. At the family level, the breadth of host associations is correlated with taxonomic diversity of the family. The degree to which factors such as intermediate host use or host specificity at any stage in the life-cycle shape these patterns is currently unknown. PMID:26994689

  15. Structural and Population Polymorphism of RT-Like Sequences in Avian Schistosomes Trichobilharzia szidati (Platyhelminthes: Digenea: Schistosomatidae)

    PubMed Central

    Semyenova, S. K.; Chrisanfova, G. G.; Guliaev, A. S.; Yesakova, A. P.; Ryskov, A. P.

    2015-01-01

    Recently we developed the genus-specific markers of the avian schistosomes of the genus Trichobilharzia, the causative agents of human cercarial dermatitis. The 7 novel genome sequences of T. franki, T. regenti, and T. szidati revealed similarity with genome repeat region of African schistosome Schistosoma mansoni. In the present work we analyzed the 37 new T. szidati sequences to study intragenome variability and host specificity for the parasite from three localities of East Europe. DNAs were isolated from cercariae or single sporocysts obtained from 6 lymnaeid snails Lymnaea stagnalis and L. palustris from Belarus and Russia. All sequences formed three diverged groups, one of which consists of the sequences with multiple deletions; other groups involved two paralogous copies with stop codons and frameshift mutations. Strong association between geographical distribution and snail host specificity cannot be established. All studied sequences have homology with the reverse transcriptase domain (RT) of Penelope-like elements (PLE) of S. mansoni and S. japonicum and new members of RT family were identified. We proposed that three diverged groups RT sequences of T. szidati are results of duplication or transposition of PLE during parasite evolution. Implications of the retroelement dynamics in the life history of avian schistosomes are discussed. PMID:26114104

  16. Light and electron microscopy observations of embryogenesis and egg development in the human liver fluke, Opisthorchis viverrini (Platyhelminthes, Digenea).

    PubMed

    Khampoosa, Panita; Jones, Malcolm K; Lovas, Erica M; Srisawangwong, Tuanchai; Laha, Thewarach; Piratae, Supawadee; Thammasiri, Chalida; Suwannatrai, Apiporn; Sripanidkulchai, Bungorn; Eursitthichai, Veerachai; Tesana, Smarn

    2012-02-01

    Eggs of most species digenean flukes hatch in the external environment to liberate larvae that seek and penetrate a snail intermediate host. Those of the human liver flukes, Opisthorchis viverrini, hatch within the gastrointestinal canal of their snail hosts. While adult parasites are primarily responsible for the pathology in cases of human opisthorchiasis, their eggs also contribute by inducing granulomata and in serving as nidi for gallstone formation. In view of the peculiar biology of O. viverrini eggs and their contribution to pathology, we investigated embryogenesis in this species by light and transmission electron microscopy. Egg development was traced from earliest stages of coalescence in the ootype until full embryonation in the distal region of the uterus. Fully mature eggs were generally impermeable to resin and could not be examined by conventional electron microscopy methods. However, the use of high-pressure freezing and freeze-substitution fixation of previously fixed eggs enabled the internal structure of mature eggs, particularly the subshell envelopes, to be elucidated. Fertilization occurs in the ootype, and the large zygote is seen therein with a single spermatozoon wrapped around its plasma membrane. As the zygote begins to divide, the spent vitellocytes are pushed to the periphery of the eggs, where they progressively degrade. The early eggshell is formed in the ootype by coalescing eggshell precursor material released by approximately six vitelline cells. The early eggs have a thinner eggshell and are larger than, but lack the characteristic shape of, mature eggs. Characteristic shell ornamentation, the "muskmelon" appearance of eggs, appears after eggshell polymerization in the ootype. Pores are not present in the shell of O. viverrini eggs. The inner and outer envelopes are poorly formed in this species, with the outer envelope evident beneath the eggshell at the opercular pole of the mature egg. The miracidium has a conical anterior end that lacks the distinctive lamellar appearance of the terebratorium of other digeneans, such as the schistosomes. The miracidium is richly glandular, containing an apical gland in the anterior end, large cephalic gland, and posterior secretory glands. Each gland contains a secretory product with different structure. The paucity of vitelline cells associating with eggs, the reduced size of eggs, and reduced complexity of the extraembryonic envelopes are interpreted as adaptations to the peculiar hatching biology of the miracidia. PMID:21786067

  17. Ribosomal DNA as molecular markers and their applications in the identification of fish parasites (Platyhelminthes: Monogenea) from India

    PubMed Central

    Chaudhary, Anshu; Verma, Chandni; Singh, Hridaya Shanker

    2014-01-01

    The development of molecular techniques for taxonomic analysis of monogenean parasites has led to a great increase for proper identification and factualness. These molecular techniques, in particular the use of molecular markers, have been used to identify and validate the monogenean parasites. Although, improvements in marker detection systems particularly of elements of rDNA like 18S, ITS and 28S used in monogeneans parasites have enabled great advances to be made in recent years in India. However, the molecular sequence analysis and phylogenetic relationships among the parasitic helminthes is unconventional in India. Many workers have been always questioned the validity of Indian species of monogeneans and emphasized the need to ascertain the status of species from Indian fish. Here we would like to provide additional resolution for the interpretation of use of molecular markers in study of monogeneans in India. This review provides an overview of current stage of studies in India that have been used in applying molecular techniques to monogenean.

  18. Evidence for differential changes of junctional complex proteins in murine neurocysticerosis dependent upon CNS vasculature

    PubMed Central

    Alvarez, Jorge I.; Teale, Judy M.

    2009-01-01

    The delicate balance required to maintain homeostasis of the central nervous system (CNS) is controlled by the blood brain barrier (BBB). Upon injury, the BBB is disrupted compromising the CNS. BBB disruption has been represented as a uniform event. However, our group has shown in a murine model of neurocysticercosis (NCC) that BBB disruption varies depending upon the anatomical site/vascular bed analyzed. In this study further understanding of the mechanisms of BBB disruption were explored in blood vessels located in leptomeninges (pial vessels) and brain parenchyma (parenchymal vessels) by examining the expression of junctional complex proteins in murine brain infected with Mesocestoides corti. Both pial and parenchymal vessels from mock infected animals showed significant colocalization of junctional proteins and displayed an organized architecture. Upon infection, the patterned organization was disrupted and in some cases, particular tight junction and adherens junction proteins were undetectable or appeared to be undergoing proteolysis. The extent and timing of these changes differed between both types of vessels (pial vessel disruption within days versus weeks for parenchymal vessels). To approach potential mechanisms, the expression and activity of matrix metalloproteinase-9 (MMP-9) was evaluated by in situ zymography. The results indicated an increase in MMP-9 activity at sites of BBB disruption exhibiting leukocyte infiltration. Moreover, the timing of MMP activity in pial and parenchymal vessels correlated with the timing of permeability disruption. Thus, breakdown of the BBB is a mutable process despite the similar structure of the junctional complex between pial and parenchymal vessels and involvement of MMP activity. PMID:17686468

  19. Development of a phase-sensitive Fourier domain optical coherence tomography system to measure mouse organ of Corti vibrations in two cochlear turns

    SciTech Connect

    Ramamoorthy, Sripriya; Zhang, Yuan; Jacques, Steven; Petrie, Tracy; Wang, Ruikang; Nuttall, Alfred L.

    2015-12-31

    In this study, we have developed a phase-sensitive Fourier-domain optical coherence tomography system to simultaneously measure the in vivo inner ear vibrations in the hook area and second turn of the mouse cochlea. This technical development will enable measurement of intra-cochlear distortion products at ideal locations such as the distortion product generation site and reflection site. This information is necessary to un-mix the complex mixture of intra-cochlear waves comprising the DPOAE and thus leads to the non-invasive identification of the local region of cochlear damage.

  20. Development of a phase-sensitive Fourier domain optical coherence tomography system to measure mouse organ of Corti vibrations in two cochlear turns

    NASA Astrophysics Data System (ADS)

    Ramamoorthy, Sripriya; Zhang, Yuan; Petrie, Tracy; Jacques, Steven; Wang, Ruikang; Nuttall, Alfred L.

    2015-12-01

    In this study, we have developed a phase-sensitive Fourier-domain optical coherence tomography system to simultaneously measure the in vivo inner ear vibrations in the hook area and second turn of the mouse cochlea. This technical development will enable measurement of intra-cochlear distortion products at ideal locations such as the distortion product generation site and reflection site. This information is necessary to un-mix the complex mixture of intra-cochlear waves comprising the DPOAE and thus leads to the non-invasive identification of the local region of cochlear damage.

  1. Selection of cell fate in the organ of Corti involves the integration of Hes/Hey signaling at the Atoh1 promoter.

    PubMed

    Abdolazimi, Yassan; Stojanova, Zlatka; Segil, Neil

    2016-03-01

    Determination of cell fate within the prosensory domain of the developing cochlear duct relies on the temporal and spatial regulation of the bHLH transcription factor Atoh1. Auditory hair cells and supporting cells arise in a wave of differentiation that patterns them into discrete rows mediated by Notch-dependent lateral inhibition. However, the mechanism responsible for selecting sensory cells from within the prosensory competence domain remains poorly understood. We show in mice that rather than being upregulated in rows of cells, Atoh1 is subject to transcriptional activation in groups of prosensory cells, and that highly conserved sites for Hes/Hey repressor binding in the Atoh1 promoter are needed to select the hair cell and supporting cell fate. During perinatal supporting cell transdifferentiation, which is a model of hair cell regeneration, we show that derepression is sufficient to induce Atoh1 expression, suggesting a mechanism for priming the 3' Atoh1 autoregulatory enhancer needed for hair cell expression. PMID:26932672

  2. The first multi-gene phylogeny of the Macrostomorpha sheds light on the evolution of sexual and asexual reproduction in basal Platyhelminthes.

    PubMed

    Janssen, Toon; Vizoso, Dita B; Schulte, Gregor; Littlewood, D Timothy J; Waeschenbach, Andrea; Schärer, Lukas

    2015-11-01

    The Macrostomorpha-an early branching and species-rich clade of free-living flatworms-is attracting interest because it contains Macrostomum lignano, a versatile model organism increasingly used in evolutionary, developmental, and molecular biology. We elucidate the macrostomorphan molecular phylogeny inferred from both nuclear (18S and 28S rDNA) and mitochondrial (16S rDNA and COI) marker genes from 40 representatives. Although our phylogeny does not recover the Macrostomorpha as a statistically supported monophyletic grouping, it (i) confirms many taxa previously proposed based on morphological evidence, (ii) permits the first placement of many families and genera, and (iii) reveals a number of unexpected placements. Specifically, Myozona and Bradynectes are outside the three classic families (Macrostomidae, Microstomidae and Dolichomacrostomidae) and the asexually fissioning Myomacrostomum belongs to a new subfamily, the Myozonariinae nov. subfam. (Dolichomacrostomidae), rather than diverging early. While this represents the first evidence for asexuality among the Dolichomacrostomidae, we show that fissioning also occurs in another Myozonariinae, Myozonaria fissipara nov. sp. Together with the placement of the (also fissioning) Microstomidae, namely as the sister taxon of Dolichomacrostomidae, this suggests that fissioning is not basal within the Macrostomorpha, but rather restricted to the new taxon Dolichomicrostomida (Dolichomacrostomidae+Microstomidae). Furthermore, our phylogeny allows new insights into the evolution of the reproductive system, as ancestral state reconstructions reveal convergent evolution of gonads, and male and female genitalia. Finally, the convergent evolution of sperm storage organs in the female genitalia appears to be linked to the widespread occurrence of hypodermic insemination among the Macrostomorpha. PMID:26093054

  3. A large 28S rDNA-based phylogeny confirms the limitations of established morphological characters for classification of proteocephalidean tapeworms (Platyhelminthes, Cestoda)

    PubMed Central

    de Chambrier, Alain; Waeschenbach, Andrea; Fisseha, Makda; Scholz, Tomáš; Mariaux, Jean

    2015-01-01

    Abstract Proteocephalidean tapeworms form a diverse group of parasites currently known from 315 valid species. Most of the diversity of adult proteocephalideans can be found in freshwater fishes (predominantly catfishes), a large proportion infects reptiles, but only a few infect amphibians, and a single species has been found to parasitize possums. Although they have a cosmopolitan distribution, a large proportion of taxa are exclusively found in South America. We analyzed the largest proteocephalidean cestode molecular dataset to date comprising more than 100 species (30 new), including representatives from 54 genera (80%) and all subfamilies, thus significantly improving upon previous works to develop a molecular phylogeny for the group. The Old World origin of proteocephalideans is confirmed, with their more recent expansion in South America. The earliest diverging lineages are composed of Acanthotaeniinae and Gangesiinae but most of the presently recognized subfamilies (and genera) appear not to be monophyletic; a deep systematic reorganization of the order is thus needed and the present subfamilial system should be abandoned. The main characters on which the classical systematics of the group has been built, such as scolex morphology or relative position of genital organs in relation to the longitudinal musculature, are of limited value, as demonstrated by the very weak support for morphologically-defined subfamilies. However, new characters, such as the pattern of uterus development, relative ovary size, and egg structure have been identified, which may be useful in defining phylogenetically well-supported subgroups. A strongly supported lineage infecting various snakes from a wide geographical distribution was found. Although several improvements over previous works regarding phylogenetic resolution and taxon coverage were achieved in this study, the major polytomy in our tree, composed largely of siluriform parasites from the Neotropics, remained unresolved and possibly reflects a rapid radiation. The genus Spasskyellina Freze, 1965 is resurrected for three species of Monticellia bearing spinitriches on the margins of their suckers. PMID:25987870

  4. A new species of Unilatus (Platyhelminthes: Monogenoidea) from the gills of Leporacanthicus galaxias Isbrücker et Nijssen (Siluriformes: Loricariidae) from Brazil.

    PubMed

    Branches, Bárbara; Domingues, Marcus V

    2014-03-01

    Unilatus irae sp. nov. (Dactylogyridae) is described from the gills of the armored catfish, Leporacanthicus galaxias Isbrücker et Nijssen (Loricariidae: Ancistrinae), from Guamá river, Pará State, Brazil. The new species can be differentiated from its cogeneners by the combination of the following features: anterior anchor with well-developed superficial root, inconspicuous deep root, shaft bent at midpoint, forming angle of approximately 60°, evenly short curved point; posterior anchor with inconspicuous roots, sclerotized cap of base with small protuberance for articulation to posterior bar; evenly curved shaft and short point; anterior bar broadly V-shaped, with small posteromedial projection; and posterior bar anteriorly expanded on it midportion, with expanded ends slightly curved in posterior direction. PMID:24570054

  5. First report of the genus Cratera (Platyhelminthes, Geoplanidae) in Argentina, with description of a new species and comments on the species of the genus.

    PubMed

    Negrete, Lisandro; Brusa, Francisco

    2016-01-01

    A new species of land planarians of the genus Cratera is described. Cratera viridimaculata sp. n. was recorded in the Atlantic Forest Ecoregion, in north-eastern Argentina, and represents the first report of the genus Cratera outside Brazil. The new species is about 50 mm in length and externally characterized by a color pattern consisting of a light green olive pigmentation on the dorsum, stippled with dark gray fine spots, and dorsal eyes. Other features regarding the internal anatomy are the presence of a glandular margin, Cutaneous Muscular Index (CMI) of 10-13%, pharynx cylindrical, prostatic vesicle extrabulbar, tubular and C-shaped, with a proximal bifurcated portion, penis papilla protrusible with ejaculatory duct widened in its distal portion, and female atrium funnel-shaped. The new species is compared and discussed with its congeners. PMID:27587974

  6. Nomina nova in Platyhelminthes pro Macrorhynchus von Graff, 1882 (non [Gmelin, 1801]; non Dunker, 1843), and Leptocleidus Mueller, 1936 (non Andrews, 1922).

    PubMed

    Hornung, Jahn J

    2016-01-01

    Two genus-group names of flat-worms-Leptocleidus Mueller, 1936 and Macrorhynchus von Graff, 1882-are junior homonyms that are preoccupied by fossil diapsid reptile genera-Leptocleidus Andrews, 1922, and Macrorhynchus Dunker, 1843-and an extant teleost fish genus-Macrorhynchus [Gmelin, 1801] ex La Cépède, 1800. These are replaced by nomina nova (Pharyngodytes nom. nov.; Graffiellus nom. nov.). Macrorhynchus [Gmelin, 1801] is an objective senior synonym of Macrorhyncus Dumeríl, 1805 ex La Cépède, 1800 (syn. nov.), and a senior homonym of Macrorhynchus Dunker, 1843, and Macrorhynchus von Graff, 1882. PMID:27615836

  7. Species of Gyrodactylus von Nordmann, 1832 (Platyhelminthes: Monogenea) from cichlids from Zambezi and Limpopo river basins in Zimbabwe and South Africa: evidence for unexplored species richness.

    PubMed

    Zahradníčková, Petra; Barson, Maxwell; Luus-Powell, Wilmien J; Přikrylová, Iva

    2016-09-01

    New findings on Gyrodactylus spp. parasitising African cichlids in southern Africa are presented, comprising data from Zimbabwe and South Africa. Morphometry of opisthaptoral hard parts in combination with nuclear ribosomal DNA sequences confirmed the presence of six species of Gyrodactylus von Nordmann, 1832. Three new species are described from fishes in Zimbabwe: Gyrodactylus chitandiri n. sp. from the gill arches of Coptodon rendalli (Boulenger) and Pseudocrenilabrus philander (Weber); Gyrodactylus occupatus n. sp. from the fins of Oreochromis niloticus (L.), Pharyngochromis acuticeps (Steindachner) and P. philander; and Gyrodactylus parisellei n. sp. from the fins of O. niloticus, P. philander and Tilapia sp. Gyrodactylus nyanzae Paperna, 1973 was also identified from the gills of O. niloticus and C. rendalli collected from two localities in Zimbabwe; these findings represent new host and locality records for this parasite. Gyrodactylus sturmbaueri Vanhove, Snoeks, Volckaert & Huyse, 2011 was identified from P. philander collected in South Africa and Zimbabwe thereby providing new host and locality records for this parasite. Finally, Gyrodactylus yacatli García-Vásquez, Hansen, Christison, Bron & Shinn, 2011 was collected from the fins of O. niloticus and P. philander studied in Zimbabwe; this represents the first record of this species from the continent of Africa. Notably, this study improves upon the knowledge of Gyrodactylus spp. parasitising cichlids from these southern African regions. All species studied were recorded from at least two different cichlid host species indicating trend for a wide range of Gyrodactylus hosts in Africa. Accordingly, this supports the idea of intensive host switching in the course of their evolution. PMID:27522367

  8. Nanoporous Structures Similar to Those Reported from Squid Sucker Teeth are also Present in Egg Shells of a Terrestrial Flatworm (Platyhelminthes; Rhabditophora; Geoplanidae) from Hachijojima (Izu Islands, Japan).

    PubMed

    Meyer-Rochow, Victor Benno; Miinalainen, Ilkka

    2016-07-01

    Shells of the egg cocoon of a terrestrial planarian (Diversibipalium sp.) from Hachijojima were found to be composed of a lattice of parallel nanotubes of ca. 120 nm diameter oriented perpendicular to the shell's surface. The arrangement of the porous proteinaceous tubes closely resembles that has recently been reported from the sucker teeth of squid and to date is the only other example of this kind of structure. Although the array of nanotubes undoubtedly contributes to the stiffness of the shell and helps protecting the embryo, questions such as to how the planary worm produces the array of nanotubes and what exactly their chemical and physical properties are versus those of the squid sucker tooth still remain to be answered. PMID:27278842

  9. First report of the genus Cratera (Platyhelminthes, Geoplanidae) in Argentina, with description of a new species and comments on the species of the genus

    PubMed Central

    Negrete, Lisandro; Brusa, Francisco

    2016-01-01

    Abstract A new species of land planarians of the genus Cratera is described. Cratera viridimaculata sp. n. was recorded in the Atlantic Forest Ecoregion, in north-eastern Argentina, and represents the first report of the genus Cratera outside Brazil. The new species is about 50 mm in length and externally characterized by a color pattern consisting of a light green olive pigmentation on the dorsum, stippled with dark gray fine spots, and dorsal eyes. Other features regarding the internal anatomy are the presence of a glandular margin, Cutaneous Muscular Index (CMI) of 10–13%, pharynx cylindrical, prostatic vesicle extrabulbar, tubular and C-shaped, with a proximal bifurcated portion, penis papilla protrusible with ejaculatory duct widened in its distal portion, and female atrium funnel-shaped. The new species is compared and discussed with its congeners. PMID:27587974

  10. The description of Gyrodactylus corleonis sp. n. and G. neretum sp. n. (Platyhelminthes: Monogenea) with comments on other gyrodactylids parasitising pipefish (Pisces: Syngnathidae).

    PubMed

    Paladini, Giuseppe; Cable, Joanne; Fioravanti, Maria Letizia; Faria, Patricia J; Shinn, Andrew P

    2010-03-01

    The current work describes two new species of Gyrodactylus von Nordmann, 1832 collected from pipefish Syngnathus scovelli (Evermann et Kendall) and Syngnathus typhle L. during two separate gyrodactylosis episodes on fish held in a public aquarium located in northern Italy. The gyrodactylids collected from the skin, fins and gills of pipefish were subjected to a morphological analysis of the attachment hooks and the morphometric data were compared to the four species of Gyrodactylus previously described from syngnathid hosts, namely G. eyipayipi Vaughan, Christison, Hansen et Shinn, 2010, G. pisculentui Williams, Kritsky, Dunnigan, Lash et Klein, 2008, G. shorti Holliman, 1963 and G. syngnathi Appleby, 1996. Principal components analysis (PCA) of the morphological data indicated six clusters; two discrete groups among the specimens taken from the pipefisli held in the Italian aquarium and four further groups representing G. eyipayipi, G. pisculentus, G. shorti and G. syngnathi. Molecular sequences of the ribosomal internal transcribed spacers (ITS1 and ITS2) and the 5.8S gene for the new species considered here were then compared with those available for other species in GenBank. The comparison did not reveal any identical match, supporting the morphological analysis that Gyrodactylus corleonis sp. n. from S. typhle and Gyrodactylus neretum sp. n. from S. scovelli represent distinct species. Both G. corleonis and G. neretum possess robust hamuli, marginal hook blades that curve smoothly from their sickle base to a point beyond the toe and, ventral bars with a broad median portion and a reduced membrane. Gyrodactylus corleonis, however, can be distinguished on the basis of its heart-shaped ventral bar; G. neretum has a 1:2 hamulus point:shaft ratio and a rectangular-shaped ventral bar. A redescription of the haptoral hard parts of the four species previously recorded on pipefish is also presented. PMID:20449996

  11. Anatomical deviation of male organs of land planarians from Rio de Janeiro, Brazil, with description of two new species of Cratera (Platyhelminthes, Tricladida).

    PubMed

    Carbayo, Fernando

    2015-01-01

    Two new land planarian species, collected in the State of Rio de Janeiro, Brazil, are described. Their external aspect is similar to that of Imbira marcusi Carbayo et al., 2013 and Pseudogeoplana theresopolitana (Schirch, 1929), respectively. The analysis of the internal organs, however, revealed they belong to the genus Cratera. The male copulatory organs of one species is very different from any other geoplaninid, for the penis papilla holds a large, distal cavity receiving the ejaculatory duct and, furthermore, the papilla projects vertically downwards from the roof of the male atrium. Thus we consider it as a new species, Cratera cuarassu sp. nov. The second species differs from its congeners in that the dorsal insertion of the penis papilla is anterior to the ventral one, and in that the female atrium is narrowed in the anterior portion. The species was found in the type locality of Pseudogeoplana theresopolitana (Schirch, 1929) and compares well with it in the external features. However, since its internal organs are unknown and the type material of the species is seemingly lost, we describe it as Cratera anamariae Carbayo, sp. nov. PMID:25781812

  12. Intraspecific pairing of planaria,Dugesia tigrina andDugesia dorotocephala (Platyhelminthes: Turbellaria), and observations on lipophilic excretory-secretory worm products.

    PubMed

    Perkins, C; Fried, B

    1982-06-01

    Intraspecific pairing of the planaria,Dugesia tigrina andD. dorotocephala, was studied for 24 hr at 22 ± 1 °C in Petri dish cultures containing an agar substrate and a water overlay. Pairing of fed planaria in the light and dark and starved planaria in the light was studied, and worms in contact or within 5 mm of each other were considered paired. Fed planaria of both species paired significantly in the light and dark, whereas starved planaria did not pair. Our results suggest that worm-emitted chemical factors are involved in intraspecific pairing of planaria. Thin-layer chromatographic analysis was used to study the release of lipophilic worm products. Phospholipids, free sterols, and free fatty acids were detected in all trials, and triglycerides in most. Thin-layer densitometric analysis was used to quantitate the weight of free sterols released by planaria. PMID:24415246

  13. Reduced Leukocyte Infiltration in Absence of Eosinophils Correlates with Decreased Tissue Damage and Disease Susceptibility in ΔdblGATA Mice during Murine Neurocysticercosis

    PubMed Central

    Mishra, Pramod K.; Li, Qun; Munoz, Luis E.; Mares, Chris A.; Morris, Elizabeth G.; Teale, Judy M.; Cardona, Astrid E.

    2016-01-01

    Neurocysticercosis (NCC) is one of the most common helminth parasitic diseases of the central nervous system (CNS) and the leading cause of acquired epilepsy worldwide. NCC is caused by the presence of the metacestode larvae of the tapeworm Taenia solium within brain tissues. NCC patients exhibit a long asymptomatic phase followed by a phase of symptoms including increased intra-cranial pressure and seizures. While the asymptomatic phase is attributed to the immunosuppressive capabilities of viable T. solium parasites, release of antigens by dying organisms induce strong immune responses and associated symptoms. Previous studies in T. solium-infected pigs have shown that the inflammatory response consists of various leukocyte populations including eosinophils, macrophages, and T cells among others. Because the role of eosinophils within the brain has not been investigated during NCC, we examined parasite burden, disease susceptibility and the composition of the inflammatory reaction in the brains of infected wild type (WT) and eosinophil-deficient mice (ΔdblGATA) using a murine model of NCC in which mice were infected intracranially with Mesocestoides corti, a cestode parasite related to T. solium. In WT mice, we observed a time-dependent induction of eosinophil recruitment in infected mice, contrasting with an overall reduced leukocyte infiltration in ΔdblGATA brains. Although, ΔdblGATA mice exhibited an increased parasite burden, reduced tissue damage and less disease susceptibility was observed when compared to infected WT mice. Cellular infiltrates in infected ΔdblGATA mice were comprised of more mast cells, and αβ T cells, which correlated with an abundant CD8+ T cell response and reduced CD4+ Th1 and Th2 responses. Thus, our data suggest that enhanced inflammatory response in WT mice appears detrimental and associates with increased disease susceptibility, despite the reduced parasite burden in the CNS. Overall reduced leukocyte infiltration due to

  14. Reduced Leukocyte Infiltration in Absence of Eosinophils Correlates with Decreased Tissue Damage and Disease Susceptibility in ΔdblGATA Mice during Murine Neurocysticercosis.

    PubMed

    Mishra, Pramod K; Li, Qun; Munoz, Luis E; Mares, Chris A; Morris, Elizabeth G; Teale, Judy M; Cardona, Astrid E

    2016-06-01

    Neurocysticercosis (NCC) is one of the most common helminth parasitic diseases of the central nervous system (CNS) and the leading cause of acquired epilepsy worldwide. NCC is caused by the presence of the metacestode larvae of the tapeworm Taenia solium within brain tissues. NCC patients exhibit a long asymptomatic phase followed by a phase of symptoms including increased intra-cranial pressure and seizures. While the asymptomatic phase is attributed to the immunosuppressive capabilities of viable T. solium parasites, release of antigens by dying organisms induce strong immune responses and associated symptoms. Previous studies in T. solium-infected pigs have shown that the inflammatory response consists of various leukocyte populations including eosinophils, macrophages, and T cells among others. Because the role of eosinophils within the brain has not been investigated during NCC, we examined parasite burden, disease susceptibility and the composition of the inflammatory reaction in the brains of infected wild type (WT) and eosinophil-deficient mice (ΔdblGATA) using a murine model of NCC in which mice were infected intracranially with Mesocestoides corti, a cestode parasite related to T. solium. In WT mice, we observed a time-dependent induction of eosinophil recruitment in infected mice, contrasting with an overall reduced leukocyte infiltration in ΔdblGATA brains. Although, ΔdblGATA mice exhibited an increased parasite burden, reduced tissue damage and less disease susceptibility was observed when compared to infected WT mice. Cellular infiltrates in infected ΔdblGATA mice were comprised of more mast cells, and αβ T cells, which correlated with an abundant CD8+ T cell response and reduced CD4+ Th1 and Th2 responses. Thus, our data suggest that enhanced inflammatory response in WT mice appears detrimental and associates with increased disease susceptibility, despite the reduced parasite burden in the CNS. Overall reduced leukocyte infiltration due to

  15. New records of Cotylea (Polycladida, Platyhelminthes) from Lizard Island, Great Barrier Reef, Australia, with remarks on the distribution of the Pseudoceros Lang, 1884 and Pseudobiceros Faubel, 1984 species of the Indo-Pacific Marine Region.

    PubMed

    Marquina, Daniel; Aguado, M Teresa; Noreña, Carolina

    2015-01-01

    In the present work eleven polyclad species of Lizard Island are studied. Seven of them are new records for this locality of the Australian coral reef and one is new to science, Lurymare clavocapitata n. sp. (Family Prosthiostomidae). The remaining recorded species belong to the genera Pseudoceros (P. bimarginatus, P. jebborum, P. stimpsoni, P. zebra, P. paralaticlavus and P. prudhoei) and Pseudobiceros (Pb. hancockanus, Pb. hymanae, Pb. flowersi and Pb. uniarborensis). Regardless of the different distribution patterns, all pseudocerotid species show brilliant colours, but similar internal morphology. Furthermore, differences in the form and size of the stylet are characteristic, because it is a sclerotic structure that is not affected during fixation. In Pseudoceros, the distance between the sucker and the female pore also differs among species. These features do not vary enough to be considered as diagnostic, but they provide information that can help to disentangle similarly coloured species complexes. A key of the genera Pseudoceros and Pseudobiceros of the Indo-Pacific region is provided, in order to facilitate the identification of species from this area. PMID:26624074

  16. First report of gastrocotylinean post-oncomiracidia (Platyhelminthes: Monogenoidea: Heteronchoinea) on gills of flyingfish (Exocoetidae), snapper (Lutjanidae), dolphinfish (Coryphaenidae), and amberjack (Carangidae) from the Gulf of Mexico: decoy hosts and the dilution effect.

    PubMed

    Kritsky, Delane C; Bullard, Stephen A; Bakenhaster, Micah D

    2011-09-01

    Larvae, identified as post-oncomiracidia of the suborder Gastrocotylinea (Monogenoidea), were collected from formalin-fixed gills excised from six species of marine fishes captured from the Gulf of Mexico off Mississippi and Florida: common dolphinfish, Coryphaena hippurus and pompano dolphinfish, Coryphaena equiselis (both Perciformes, Coryphaenidae); gray snapper, Lutjanus griseus (Perciformes, Lutjanidae); greater amberjack, Seriola dumerili (Perciformes, Carangidae); and Atlantic flyingfish, Cheilopogon melanurus and sailfin flyingfish, Parexocoetus hillianus (both Beloniformes and Exocoetidae). Based on a combination of diagnostic morphological features, the specimens were divided into two basic forms, each of which was further subdivided into two morphotypes. No gastrocotylinean post-oncomiracidium had been reported previously from these hosts. Of the six host species, only C. hippurus serves as a host (unconfirmed) for the adult of a gastrocotylinean species, suggesting that the recorded fishes from the Gulf of Mexico comprise dead-end hosts acting as decoys for the oncomiracidia. These comparatively non-susceptible "decoy hosts" apparently dilute the susceptible fish-host population and by intercepting infective larvae (oncomiracidia) decrease the abundance of parasites on their typical hosts. PMID:21497672

  17. A new species of Acanthocotyle Monticelli, 1888 (Platyhelminthes: Monogenea: Acanthocotylidae) from the ventral skin of the banded stingaree, Urolophus cruciatus (Lacépède, 1804), from Tasmania, Australia.

    PubMed

    Kearn, Graham; Whittington, Ian; Chisholm, Leslie; Evans-Gowing, Richard

    2016-09-01

    Acanthocotyle urolophi sp. nov. is described from the skin of the banded stingaree, Urolophus cruciatus (Lacépède, 1804). This is the first acanthocotylid to be described from Australian waters. Acanthocotyle urolophi sp. nov. is distinguished from other species of Acanthocotyle by a combination of the number of vitelline follicles 38 (33-46) and the number of rows 35 (32-37) of sclerites on the pseudohaptor. In addition, Acanthocotyle urolophi sp. nov. has no germarial appendix and no uterine "arm". A uterine receptaculum seminis was not identified in whole mounts. There is no penis papilla and no penis sclerite associated with the male reproductive opening. A brief description of the larva is provided. The diagnosis of the Acanthocotylidae Price, 1936 is amended and we review the Allacanthocotylinae Yamaguti, 1963, Lophocotylinae Yamaguti, 1963 and Pseudacanthocotylinae Yamaguti, 1963. We deem that these subfamilies are invalid and that the family now comprises only the subfamily Acanthocotylinae and the genus Acanthocotyle. The validity of species previously assigned to the Acanthocotylidae (sensu Yamaguti, 1963) is discussed and a key to what we consider to be the valid species in the family is also provided. PMID:27447227

  18. Dactylogyrids (Platyhelminthes: Monogenoidea) parasitizing butterfly fishes (Teleostei: Chaetodontidae) from the coral reefs of Palau, Moorea, Wallis, New Caledonia, and Australia: species of Euryhaliotrematoides n. gen. and Aliatrema n. gen.

    PubMed

    Plaisance, Laetitia; Kritsky, Delane C

    2004-04-01

    Seven species of Euryhaliotrematoides n. gen. and 1 species of Aliatrema n. gen. (Monogenoidea; Dactylogyridae) are described and reported from the gills of 15 species of butterfly fishes (Chaetodontidae) from the coral reefs of Moorea (French Polynesia), Wallis (Wallis and Futuna), Heron and Lizard (Australia), Palau (Micronesia), and New Caledonia: Aliatrema cribbi n. sp. from Chaetodon auriga, Chaetodon lunula, Chaetodon trifasciatus, Chaetodon ulietensis, Chaetodon vagabundus, Forcipiger flavisissimus, and Heniochus chrysostomus; Euryhaliotrematoides annulocirrus n. comb. from C. auriga, C. lunula, and C. vagabundus; Euryhaliotrematoides aspistis n. sp. from C. auriga, Chaetodon citrinellus, C. lunula, Chaetodon reticulatus, C. ulietensis, and C. vagabundus; Euryhaliotrematoides berenguelae n. sp. from C. citrinellus, Chaetodon ornatissimus, and F. flavisissimus; Euryhaliotrematoides grandis n. comb. from C. auriga, C. citrinellus, Chaetodon ephippium, Chaetodon kleinii, Chaetodon lineolatus, C. lunula, C. ornatissimus, C. trifasciatus, C. vagabundus, and H. chrysostomus; Euryhaliotrematoides microphallus n. comb. from C. auriga, C. citrinellus, C. ephippium, C. kleinii, C. lunula, C. ornatissimus, C. reticulatus, Chaetodon trifascialis, C. trifasciatus, C. vagabundus, F. flavisissimus, and H. chrysostomus; Euryhaliotrematoides pirulum n. sp. from C. auriga, C. citrinellus, C. lunula, C. trifasciatus, and C. vagabundus; and Euryhaliotrematoides triangulovagina n. comb. from C. auriga, C. citrinellus, C. kleinii, C. lunula, C. ornatissimus, C. vagabundus, F. flavisissimus, H. chrysostomus, and Hemitaurichthys polylepis. All reports of previously described species are new locality records. With exceptions of E. grandis and E. annulocirrus on C. auriga and C. lunula and E. triangulovagina and E. microphallus on C. auriga, all reports are new host records. Haliotrema hainanensis and H. affinis are considered junior subjective synonyms of E. triangulovagina and E. annulocirrus, respectively. Aliatrema n. gen. is characterized by marine dactylogyrids with tandem gonads (germarium pretesticular), haptoral hooks with upright acute thumbs, a coiled copulatory organ with counterclockwise rings and funnel-shaped base but lacking an accessory piece, and a dextral vaginal pore. Euryhaliotrematoides n. gen. is characterized by marine dactylogyrids having tandem gonads (germarium pretesticular), haptoral hooks with upright acute thumbs, a coiled copulatory organ with counterclockwise rings and funnel-shaped base, a vas deferens looping the left intestinal cecum, and a dextral vaginal pore. PMID:15165056

  19. Revision of Potamotrygonocotyle Mayes, Brooks & Thorson, 1981 (Platyhelminthes: Monogenoidea: Monocotylidae), with descriptions of four new species from the gills of the freshwater stingrays Potamotrygon spp. (Rajiformes: Potamotrygonidae) from the La Plata river basin.

    PubMed

    Domingues, Marcus V; Marques, Fernando P L

    2007-07-01

    The only known monocotylid genus to parasitise Neotropical freshwater stingrays (Potamotrygonidae) is Potamotrygonocotyle Mayes, Brooks & Thorson, 1981, a monotypic genus erected to accommodate P. tsalickisi Mayes, Brooks & Thorson, 1981. For more than 20 years, no other species has been recognised in this genus, but new efforts to survey the diversity of parasites inhabiting potamotrygonids have revealed the existence of new species and the need to redefine the genus. Here, the generic diagnosis of Potamotrygonocotyle is amended, P. tsalickisi is redescribed and four new species are recognised and described based on samples collected from the gills of freshwater potamotrygonids from the La Plata river basin: Potamotrygonocotyle chisholmae n. sp. and P. dromedarius n. sp. from Potamotrygon motoro; Potamotrygonocotyle eurypotamoxenus n. sp. from Potamotrygon cf. motoro (type-host), P. castexi, P. falkneri and P. histrix; and Potamotrygonocotyle uruguayensis n. sp. from Potamotrygon brachyura. Potamotrygonocotyle is characterised by species possessing: (1) slightly sinuous sclerotised ridges on all septa; (2) two pairs of the dorsal haptoral accessory structures associated with the four posterior peripheral loculi and with anterior dorsal haptoral accessory structure bilobate or semicircular; and (3) male copulatory organ without an accessory piece. PMID:17464482

  20. Morphological and molecular description of eight new species of Gyrodactylus von Nordmann, 1832 (Platyhelminthes: Monogenea) from poeciliid fishes, collected in their natural distribution range in the Gulf of Mexico slope, Mexico.

    PubMed

    García-Vásquez, Adriana; Razo-Mendivil, Ulises; Rubio-Godoy, Miguel

    2015-09-01

    Eight new species of Gyrodactylus are described from Poecilia mexicana, Poeciliopsis gracilis, Pseudoxiphophorus bimaculatus [syn. = Heterandria bimaculata], and Xiphophorus hellerii collected in the Nautla and La Antigua River Basins in Veracruz, and in the Tecolutla River Basin in Puebla, Mexico. Analyzing the morphology of the marginal hooks, Gyrodactylus pseudobullatarudis n. sp. and Gyrodactylus xtachuna n. sp. are both very similar to Gyrodactylus bullatarudis; Gyrodactylus takoke n. sp. resembles Gyrodactylus xalapensis; Gyrodactylus lhkahuili n. sp. is similar to Gyrodactylus jarocho; and both Gyrodactylus microdactylus n. sp. and Gyrodactylus actzu n. sp. are similar to Gyrodactylus poeciliae in that all three species possess extremely short shaft points. A hypothesis of the systematic relationships of the eight new Gyrodactylus species and some of the known gyrodactylids infecting poeciliids was constructed with sequences of the Internal Transcribed Spacers (ITS1 and ITS2) and the 5.8S ribosomal gene of the rRNA. Phylogenetic trees showed that the new and previously described species of Gyrodactylus infecting poeciliid fishes do not form a monophyletic assemblage. Trees also showed that the eight new species described morphologically correspond to well-supported monophyletic groups; and that morphologically similar species are also phylogenetically close. Additionally, we correct previous erroneous records of the presence of Gyrodactylus bullatarudis on wild Poecilia mexicana and Xiphophorus hellerii collected in Mexico, as re-examination of the original specimens indicated that these corresponded to Gyrodactylus pseudobullatarudis n. sp. (infecting Poecilia mexicana and Xiphophorus hellerii) and to Gyrodactylus xtachuna n. sp. (on Xiphophorus hellerii). Finally, given the widespread anthropogenic translocation of poeciliid fishes for the aquarium trade and mosquito control programs, as well as the existence of invasive, feral poeciliid populations worldwide, we discuss the possibility that gyrodactylid parasites could be introduced along with the fish hosts-this work provides taxonomic information to assess that possibility, as it describes parasites collected from poeciliid fishes within their native distribution range. PMID:26091759

  1. Integrative taxonomy of a new species of planarian from the Lake Ohrid basin, including an analysis of biogeographical patterns in freshwater triclads from the Ohrid region (Platyhelminthes, Tricladida, Dugesiidae)

    PubMed Central

    Stocchino, Giacinta Angela; Sluys, Ronald; Deri, Paolo; Manconi, Renata

    2013-01-01

    Abstract A new species of the genus Dugesia is described from the Lake Ohrid region in the western part of the Balkan Peninsula, forming the first fully documented species description for this genus in the Ohrid area. The morphological species delimitation is supported by complementary molecular, karyological, and cytogenetic data available from the literature. Therefore, species delineation is based on a truly integrative approach. Further, a short account on the degree of freshwater planarian endemicity in the Ohrid region is provided. PMID:23840163

  2. Integrative taxonomy of a new species of planarian from the Lake Ohrid basin, including an analysis of biogeographical patterns in freshwater triclads from the Ohrid region (Platyhelminthes, Tricladida, Dugesiidae).

    PubMed

    Stocchino, Giacinta Angela; Sluys, Ronald; Deri, Paolo; Manconi, Renata

    2013-01-01

    A new species of the genus Dugesia is described from the Lake Ohrid region in the western part of the Balkan Peninsula, forming the first fully documented species description for this genus in the Ohrid area. The morphological species delimitation is supported by complementary molecular, karyological, and cytogenetic data available from the literature. Therefore, species delineation is based on a truly integrative approach. Further, a short account on the degree of freshwater planarian endemicity in the Ohrid region is provided. PMID:23840163

  3. Neuropeptide physiology in helminths.

    PubMed

    Mousley, Angela; Novozhilova, Ekaterina; Kimber, Michael J; Day, Tim A

    2010-01-01

    Parasitic worms come from two distinct, distant phyla, Nematoda (roundworms) and Platyhelminthes (flatworms). The nervous systems of worms from both phyla are replete with neuropeptides and there is ample physiological evidence that these neuropeptides control vital aspects of worm biology. In each phyla, the physiological evidence for critical roles for helminth neuropeptides is derived from both parasitic and free-living members. In the nematodes, the intestinal parasite Ascaris suum and the free-living Caenorhabditis elegans have yielded most of the data; in the platyhelminths, the most physiological data has come from the blood fluke Schistosoma mansoni. FMRFamide-like peptides (FLPs) have many varied effects (excitation, relaxation, or a combination) on somatic musculature, reproductive musculature, the pharynx and motor neurons in nematodes. Insulin-like peptides (INSs) play an essential role in nematode dauer formation and other developmental processes. There is also some evidence for a role in somatic muscle control for the somewhat heterogeneous grouping ofpeptides known as neuropeptide-like proteins (NLPs). In platyhelminths, as in nematodes, FLPs have a central role in somatic muscle function. Reports of FLP physiological action in platyhelminths are limited to a potent excitation of the somatic musculature. Platyhelminths are also abundantly endowed with neuropeptide Fs (NPFs), which appear absent from nematodes. There is not yet any data linking platyhelminth NPF to any particular physiological outcome, but this neuropeptide does potently and specifically inhibit cAMP accumulation in schistosomes. In nematodes and platyhelminths, there is an abundance of physiological evidence demonstrating that neuropeptides play critical roles in the biology of both free-living and parasitic helminths. While it is certainly true that there remains a great deal to learn about the biology of neuropeptides in both phyla, physiological evidence presently available points

  4. Phylogenetic position of Nemertea derived from phylogenomic data.

    PubMed

    Struck, Torsten H; Fisse, Frauke

    2008-04-01

    Nemertea and Platyhelminthes have traditionally been grouped together because they possess a so-called acoelomate organization, but lateral vessels and rhynchocoel of nemerteans have been regarded as coelomic cavities. Additionally, both taxa show spiral cleavage patterns prompting the placement of Nemertea as sister to coelomate Protostomia, that is, either to Neotrochozoa (Mollusca and Annelida) or to Teloblastica (Neotrochozoa plus Arthropoda). Some workers maintain a sister group relationship of Nemertea and Platyhelminthes as Parenchymia because of an assumed homology of Götte's and Müller's larvae of polyclad Platyhelminthes and the pilidium larvae of heteronemerteans. So far, molecular data were only able to significantly reject a sister group relationship to Teloblastica. Although phylogenomic data are available for Platyhelminthes, Annelida, Mollusca, and Arthropoda, they are lacking for Nemertea. Herein, we present the first analysis specifically addressing nemertean phylogenetic position using phylogenomic data. More specifically, we collected expressed sequence tag data from Lineus viridis (O.F. Müller, 1774) and combined it with available data to produce a data set of 9,377 amino acid positions from 60 ribosomal proteins. Maximum likelihood analyses and Bayesian inferences place Nemertea in a clade together with Annelida and Mollusca. Furthermore, hypothesis testing significantly rejected a sister group relationship to either Platyhelminthes or Teloblastica. The Coelomata hypothesis, which groups coelomate taxa together to the exclusion of acoelomate and pseudocoelomate taxa, is not congruent with our results. Thus, the supposed acoelomate organization evolved independently in Nemertea and Platyhelminthes. In Nemertea, evolution of acoely is most likely due to a secondary reduction of the coelom as it is found in certain species of Mollusca and Annelida. Though looking very similar, the Götte's and Müller's larvae of polyclad Platyhelminthes are

  5. Echinococcus granulosus fatty acid binding proteins subcellular localization.

    PubMed

    Alvite, Gabriela; Esteves, Adriana

    2016-05-01

    Two fatty acid binding proteins, EgFABP1 and EgFABP2, were isolated from the parasitic platyhelminth Echinococcus granulosus. These proteins bind fatty acids and have particular relevance in flatworms since de novo fatty acids synthesis is absent. Therefore platyhelminthes depend on the capture and intracellular distribution of host's lipids and fatty acid binding proteins could participate in lipid distribution. To elucidate EgFABP's roles, we investigated their intracellular distribution in the larval stage by a proteomic approach. Our results demonstrated the presence of EgFABP1 isoforms in cytosolic, nuclear, mitochondrial and microsomal fractions, suggesting that these molecules could be involved in several cellular processes. PMID:26873273

  6. To Be or Not to Be a Flatworm: The Acoel Controversy

    PubMed Central

    Arendt, Detlev; Borgonie, Gaëtan; Funayama, Noriko; Gschwentner, Robert; Hartenstein, Volker; Hobmayer, Bert; Hooge, Matthew; Hrouda, Martina; Ishida, Sachiko; Kobayashi, Chiyoko; Kuales, Georg; Nishimura, Osamu; Pfister, Daniela; Rieger, Reinhard; Salvenmoser, Willi; Smith, Julian; Technau, Ulrich; Tyler, Seth; Agata, Kiyokazu; Salzburger, Walter; Ladurner, Peter

    2009-01-01

    Since first described, acoels were considered members of the flatworms (Platyhelminthes). However, no clear synapomorphies among the three large flatworm taxa - the Catenulida, the Acoelomorpha and the Rhabditophora - have been characterized to date. Molecular phylogenies, on the other hand, commonly positioned acoels separate from other flatworms. Accordingly, our own multi-locus phylogenetic analysis using 43 genes and 23 animal species places the acoel flatworm Isodiametra pulchra at the base of all Bilateria, distant from other flatworms. By contrast, novel data on the distribution and proliferation of stem cells and the specific mode of epidermal replacement constitute a strong synapomorphy for the Acoela plus the major group of flatworms, the Rhabditophora. The expression of a piwi-like gene not only in gonadal, but also in adult somatic stem cells is another unique feature among bilaterians. These two independent stem-cell-related characters put the Acoela into the Platyhelminthes-Lophotrochozoa clade and account for the most parsimonious evolutionary explanation of epidermal cell renewal in the Bilateria. Most available multigene analyses produce conflicting results regarding the position of the acoels in the tree of life. Given these phylogenomic conflicts and the contradiction of developmental and morphological data with phylogenomic results, the monophyly of the phylum Platyhelminthes and the position of the Acoela remain unresolved. By these data, both the inclusion of Acoela within Platyhelminthes, and their separation from flatworms as basal bilaterians are well-supported alternatives. PMID:19430533

  7. To be or not to be a flatworm: the acoel controversy.

    PubMed

    Egger, Bernhard; Steinke, Dirk; Tarui, Hiroshi; De Mulder, Katrien; Arendt, Detlev; Borgonie, Gaëtan; Funayama, Noriko; Gschwentner, Robert; Hartenstein, Volker; Hobmayer, Bert; Hooge, Matthew; Hrouda, Martina; Ishida, Sachiko; Kobayashi, Chiyoko; Kuales, Georg; Nishimura, Osamu; Pfister, Daniela; Rieger, Reinhard; Salvenmoser, Willi; Smith, Julian; Technau, Ulrich; Tyler, Seth; Agata, Kiyokazu; Salzburger, Walter; Ladurner, Peter

    2009-01-01

    Since first described, acoels were considered members of the flatworms (Platyhelminthes). However, no clear synapomorphies among the three large flatworm taxa -- the Catenulida, the Acoelomorpha and the Rhabditophora -- have been characterized to date. Molecular phylogenies, on the other hand, commonly positioned acoels separate from other flatworms. Accordingly, our own multi-locus phylogenetic analysis using 43 genes and 23 animal species places the acoel flatworm Isodiametra pulchra at the base of all Bilateria, distant from other flatworms. By contrast, novel data on the distribution and proliferation of stem cells and the specific mode of epidermal replacement constitute a strong synapomorphy for the Acoela plus the major group of flatworms, the Rhabditophora. The expression of a piwi-like gene not only in gonadal, but also in adult somatic stem cells is another unique feature among bilaterians. These two independent stem-cell-related characters put the Acoela into the Platyhelminthes-Lophotrochozoa clade and account for the most parsimonious evolutionary explanation of epidermal cell renewal in the Bilateria. Most available multigene analyses produce conflicting results regarding the position of the acoels in the tree of life. Given these phylogenomic conflicts and the contradiction of developmental and morphological data with phylogenomic results, the monophyly of the phylum Platyhelminthes and the position of the Acoela remain unresolved. By these data, both the inclusion of Acoela within Platyhelminthes, and their separation from flatworms as basal bilaterians are well-supported alternatives. PMID:19430533

  8. Gain and frequency tuning within the mouse cochlear apex

    NASA Astrophysics Data System (ADS)

    Oghalai, John S.; Gao, Simon; Lee, Hee Yoon; Raphael, Patrick D.; Groves, Andrew K.; Zuo, Jian; Applegate, Brian E.

    2015-12-01

    Normal mammalian hearing requires cochlear outer hair cell active processes that amplify the traveling wave with high gain and sharp tuning, termed cochlear amplification. We have used optical coherence tomography to study cochlear amplification within the apical turn of the mouse cochlea. We measured not only classical basilar membrane vibratory tuning curves but also vibratory responses from the rest of the tissues that compose the organ of Corti. Basilar membrane tuning was sharp in live mice and broad in dead mice, whereas other regions of the organ of Corti demonstrated phase shifts consistent with additional filtering beyond that provided by basilar membrane mechanics. We use these experimental data to support a conceptual framework of how cochlear amplification is tuned within the mouse cochlear apex. We will also study transgenic mice with targeted mutations that affect different biomechanical aspects of the organ of Corti in an effort to localize the underlying processes that produce this additional filtering.

  9. Gain and frequency tuning within the mouse cochlear apex

    SciTech Connect

    Oghalai, John S.; Raphael, Patrick D.; Gao, Simon; Lee, Hee Yoon; Groves, Andrew K.; Zuo, Jian; Applegate, Brian E.

    2015-12-31

    Normal mammalian hearing requires cochlear outer hair cell active processes that amplify the traveling wave with high gain and sharp tuning, termed cochlear amplification. We have used optical coherence tomography to study cochlear amplification within the apical turn of the mouse cochlea. We measured not only classical basilar membrane vibratory tuning curves but also vibratory responses from the rest of the tissues that compose the organ of Corti. Basilar membrane tuning was sharp in live mice and broad in dead mice, whereas other regions of the organ of Corti demonstrated phase shifts consistent with additional filtering beyond that provided by basilar membrane mechanics. We use these experimental data to support a conceptual framework of how cochlear amplification is tuned within the mouse cochlear apex. We will also study transgenic mice with targeted mutations that affect different biomechanical aspects of the organ of Corti in an effort to localize the underlying processes that produce this additional filtering.

  10. Audiogenic seizures and cochlear damage in rats after perinatal antithyroid treatment

    SciTech Connect

    Van Milllesworth, L.; Norris, C.H.

    1980-06-01

    The feeding of goitrogens during pregnancy and lactation causes the offspring of rats to be partially deaf and persistently sensitive to audiogenic seizures. The most potent goitrogen, propylthiouracil, caused severe dysfunction and disorganization of the organ of Corti. Adult seizure-susceptible rats showed increased sensitivity to audiogenic seizures when they were fed propylthiouracil.

  11. Conditioned pain modulation in women with irritable bowel syndrome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evidence suggests that patients with irritable bowel syndrome (IBS) are more vigilant to pain-associated stimuli. The aims of this study were to compare women with IBS (n = 20) to healthy control (HC, n = 20) women on pain sensitivity, conditioned pain modulation (CPM) efficiency, and salivary corti...

  12. Auditory system

    NASA Technical Reports Server (NTRS)

    Ades, H. W.

    1973-01-01

    The physical correlations of hearing, i.e. the acoustic stimuli, are reported. The auditory system, consisting of external ear, middle ear, inner ear, organ of Corti, basilar membrane, hair cells, inner hair cells, outer hair cells, innervation of hair cells, and transducer mechanisms, is discussed. Both conductive and sensorineural hearing losses are also examined.

  13. Acoustic Responses after Total Destruction of the Cochlear Receptor: Brainstem and Auditory Cortex

    NASA Astrophysics Data System (ADS)

    Cazals, Yves; Aran, Jean-Marie; Erre, Jean-Paul; Guilhaume, Anne

    1980-10-01

    Acoustically evoked neural activity has been recorded from the brainstem and auditory cortex of guinea pigs after complete destruction of the organ of Corti by the aminoglycosidic antibiotic amikacin. These responses to sound differ in important respects from the evoked potentials normally recorded from the auditory pathways. At the brainstem level they resemble the potentials reported by others after stimulation of the vestibular nerve.

  14. The Parasite Fauna of the Gyrfalcon (Falco rusticolus) in Iceland.

    PubMed

    Christensen, Nanna D; Skirnisson, Karl; Nielsen, Ólafur K

    2015-10-01

    We examined 46 Gyrfalcon (Falco rusticolus) carcasses from Iceland for parasites, including 29 first-year birds and 17 second-year birds and older. Endoparasites observed were the trematodes Cryptocotyle lingua (prevalence 8%), Cryptocotyle concavum (4%), and Strigea sp. (8%); the cestode Mesocestoides sp. (27%); and the nematodes Eucoleus contortus (76%) and Serratospiculum guttatum (7%). Ectoparasites included the astigmatan mite Dubininia accipitrina (47%), a mesostigmatan rhynonyssid mite (4%), the tick Ixodes caledonicus (20%), the mallophagans Degeeriella rufa (90%) and Nosopon lucidum (7%), the flea Ceratophyllus vagabundus (7%), and the louse fly Ornithomya chloropus (7%). Cryptocotyle lingua, C. concavum, S. guttatum, D. accipitrina, I. caledonicus, and N. lucidum are new host records. Of the five most common parasites (prevalence ≥ 20%) only Mesocestoides sp. showed a significant age relationship, being more prevalent in adult falcons (P = 0.021). Eucoleus contortus was also more prevalent in adults with marginal statistical significance (P = 0.058). Frounce, caused by E. contortus (possibly also by Trichomonas gallinae, which was not searched for in the survey) was highly prevalent (43%), but did not show a relationship with host age (P = 0.210). Birds with frounce were in poorer body condition than healthy birds (P = 0.015). PMID:26280881

  15. Helminths of red foxes (Vulpes vulpes) in Denmark.

    PubMed

    Saeed, I; Maddox-Hyttel, C; Monrad, J; Kapel, C M O

    2006-06-30

    An epidemiological study of helminths in 1040 red foxes collected from various localities in Denmark during 1997-2002, revealed 21 helminth species at autopsy, including nine nematode species: Capillaria plica (prevalence 80.5%), Capillaria aerophila (74.1%), Crenosoma vulpis (17.4%), Angiostrongylus vasorum (48.6% from Northern Zealand (endemic area)), Toxocara canis (59.4%), Toxascaris leonina (0.6%), Uncinaria stenocephala (68.6%), Ancylostoma caninum (0.6%), and Trichuris vulpis (0.5%); seven cestodes: Mesocestoides sp. (35.6%), a number of Taeniid species (Taenia pisiformis, T. hydatigena, T. taeniaeformis, T. crassiceps, and unidentified Taenia spp.) (22.8%), and Echinococcus multilocularis (0.3%); four trematodes: Alaria alata (15.4%), Cryptocotyle lingua (23.8%), Pseudamphystomum truncatum (3.6% from Northern Zealand), and Echinochasmus perfoliatus (2.4% from Northern Zealand); one acanthocephalan: Polymorphus sp. (1.2%). Significant difference in prevalence was found for T. canis and A. vasorum according to host sex, and for T. canis, U. stenocephala, Mesocestoides sp., Taenia spp., A. alata, A. vasorum, and Capillaria spp. according to age groups (adult, young or cub). Prevalence and average worm intensity for each helminth species varied considerably according to geographical locality, season, and year. Aggregated distribution was found for several helminth species. The two species E. multilocularis and E. perfoliatus are first records for Denmark. PMID:16580775

  16. Levels of infection of intestinal helminth species in the golden jackal Canis aureus from Serbia.

    PubMed

    Ćirović, D; Pavlović, I; Penezić, A; Kulišić, Z; Selaković, S

    2015-01-01

    During the past decade, golden jackal populations have substantially increased, yet little is known of their potential for transmitting parasites within animal and human hosts. In the present study, between 2005 and 2010, 447 jackals from six localities in Serbia were examined for intestinal parasites. Two species of trematodes (Alaria alata, Pseudamphistomum truncatum), three nematodes (Toxocara canis, Ancylostoma caninum, Gongylonema sp.), and seven cestodes (Taenia pisiformis, Taenia hydatigena, Multiceps multiceps, Multiceps serialis, Mesocestoides lineatus, Mesocestoides litteratus, Dipylidium caninum) were identified. Pseudamphistomum truncatum and M. serialis species were recorded for the first time. The overall prevalence of parasitic infection was 10.3%. No significant differences were found in the prevalence of infection between males and females (P>0.817), between localities (P>0.502), or with regard to annual cycles (P>0.502). In the infected jackal population, 65% harboured multiple infections and one individual was a host to five different types of parasite species, the highest number of parasites we recorded in a single host. These findings indicate that although the prevalence of gastrointestinal helminths in the jackal population in Serbia is significantly lower than expected from earlier studies, further monitoring is required given the jackal's rapid population increase. PMID:23941681

  17. The urbilaterian brain revisited: novel insights into old questions from new flatworm clades.

    PubMed

    Bailly, Xavier; Reichert, Heinrich; Hartenstein, Volker

    2013-05-01

    Flatworms are classically considered to represent the simplest organizational form of all living bilaterians with a true central nervous system. Based on their simple body plans, all flatworms have been traditionally grouped together in a single phylum at the base of the bilaterians. Current molecular phylogenomic studies now split the flatworms into two widely separated clades, the acoelomorph flatworms and the platyhelminth flatworms, such that the last common ancestor of both clades corresponds to the urbilaterian ancestor of all bilaterian animals. Remarkably, recent comparative neuroanatomical analyses of acoelomorphs and platyhelminths show that both of these flatworm groups have complex anterior brains with surprisingly similar basic neuroarchitectures. Taken together, these findings imply that fundamental neuroanatomical features of the brain in the two separate flatworm groups are likely to be primitive and derived from the urbilaterian brain. PMID:23143292

  18. THE URBILATERIAN BRAIN REVISITED: NOVEL INSIGHTS INTO OLD QUESTIONS FROM NEW FLATWORM CLADES

    PubMed Central

    Bailly, Xavier; Reichert, Heinrich; Hartenstein, Volker

    2012-01-01

    SUMMARY Flatworms are classically considered to represent the simplest organizational form of all living bilaterians with a true central nervous system. Based on their simple body plans, all flatworms have been traditionally grouped together in a single phylum at the base of the bilaterians. Current molecular phylogenomic studies now split the flatworms into two widely separated clades, the acoelomorph flatworms and the platyhelminth flatworms, such that the last common ancestor of both clades corresponds to the urbilaterian ancestor of all bilaterian animals. Remarkably, recent comparative neuroanatomical analyses of acoelomorphs and platyhelminths show that both of these flatworm groups have complex anterior brains with surprisingly similar basic neuroarchitectures. Taken together, these findings imply that fundamental neuroanatomical features of the brain in the two separate flatworm groups are likely to be primitive and derived from the urbilaterian brain. PMID:23143292

  19. Phylogenetic analysis of the endoribonuclease Dicer family.

    PubMed

    Gao, Zeqian; Wang, Miao; Blair, David; Zheng, Yadong; Dou, Yongxi

    2014-01-01

    Dicers are proteins of the ribonuclease III family with the ability to process dsRNA, involved in regulation of gene expression at the post-transcriptional level. Dicers are conserved from basal metazoans to higher metazoans and contain a number of functional domains that interact with dsRNA. The completed genome sequences of over 34 invertebrate species allowed us to systematically investigate Dicer genes over a diverse range of phyla. The majority of invertebrate Dicers clearly fell into the Dicer1 or Dicer2 subfamilies. Most nematodes possessed only one Dicer gene, a member of the Dicer1 subfamily, whereas two Dicer genes (Dicer1 and Dicer2) were present in all platyhelminths surveyed. Analysis of the key domains showed that a 5' pocket was conserved across members of the Dicer1 subfamily, with the exception of the nematode Bursaphelenchus xylophilus. Interestingly, Nematostella vectensis DicerB grouped into Dicer2 subfamily harbored a 5' pocket, which is commonly present in Dicer1. Similarly, the 3' pocket was also found to be conserved in all Dicer proteins with the exceptions of Schmidtea mediterranea Dicer2 and Trichoplax adherens Dicer A. The loss of catalytic residues in the RNase III domain was noted in platyhelminths and cnidarians, and the 'ball' and 'socket' junction between two RNase III domains in platyhelminth Dicers was different from the canonical junction, suggesting the possibility of different conformations. The present data suggest that Dicers might have duplicated and diversified independently, and have evolved for various functions in invertebrates. PMID:24748168

  20. Retinoic Acid Stimulates Regeneration of Mammalian Auditory Hair Cells

    NASA Astrophysics Data System (ADS)

    Lefebvre, Philippe P.; Malgrange, Brigitte; Staecker, Hinrich; Moonen, Gustave; van de Water, Thomas R.

    1993-04-01

    Sensorineural hearing loss resulting from the loss of auditory hair cells is thought to be irreversible in mammals. This study provides evidence that retinoic acid can stimulate the regeneration in vitro of mammalian auditory hair cells in ototoxic-poisoned organ of Corti explants in the rat. In contrast, treatment with retinoic acid does not stimulate the formation of extra hair cells in control cultures of Corti's organ. Retinoic acid-stimulated hair cell regeneration can be blocked by cytosine arabinoside, which suggests that a period of mitosis is required for the regeneration of auditory hair cells in this system. These results provide hope for a recovery of hearing function in mammals after auditory hair cell damage.

  1. Inner ear hair cells deteriorate in mice engineered to have no or diminished innervation

    PubMed Central

    Kersigo, Jennifer; Fritzsch, Bernd

    2015-01-01

    The innervation of the inner ear critically depends on the two neurotrophins Ntf3 and Bdnf. In contrast to this molecularly well-established dependency, evidence regarding the need of innervation for long-term maintenance of inner ear hair cells is inconclusive, due to experimental variability. Mutant mice that lack both neurotrophins could shed light on the long-term consequences of innervation loss on hair cells without introducing experimental variability, but do not survive after birth. Mutant mice with conditional deletion of both neurotrophins lose almost all innervation by postnatal day 10 and show an initially normal development of hair cells by this stage. No innervation remains after 3 weeks and complete loss of all innervation results in near complete loss of outer and many inner hair cells of the organ of Corti within 4 months. Mutants that retain one allele of either neurotrophin have only partial loss of innervation of the organ of Corti and show a longer viability of cochlear hair cells with more profound loss of inner hair cells. By 10 months, hair cells disappear with a base to apex progression, proportional to the residual density of innervation and similar to carboplatin ototoxicity. Similar to reports of hair cell loss after aminoglycoside treatment, blobbing of stereocilia of apparently dying hair cells protrude into the cochlear duct. Denervation of vestibular sensory epithelia for several months also resulted in variable results, ranging from unusual hair cells resembling the aberrations found in the organ of Corti, to near normal hair cells in the canal cristae. Fusion and/or resorption of stereocilia and loss of hair cells follows a pattern reminiscent of Myo6 and Cdc42 null mice. Our data support a role of innervation for long-term maintenance but with a remarkable local variation that needs to be taken into account when attempting regeneration of the organ of Corti. PMID:25852547

  2. Protein-Engineered Hydrogel Encapsulation for 3-D Culture of Murine Cochlea

    PubMed Central

    Chang, David T.; Chai, Renjie; DiMarco, Rebecca; Heilshorn, Sarah C.; Cheng, Alan G.

    2016-01-01

    Hypothesis Elastin-like protein (ELP) hydrogel helps maintain the three-dimensional (3-D) cochlear structure in culture. Background Whole-organ culture of the cochlea is a useful model system facilitating manipulation and analysis of live sensory cells and surrounding nonsensory cells. The precisely organized 3-D cochlear structure demands a culture method that preserves this delicate architecture; however, current methods have not been optimized to serve such a purpose. Methods A protein-engineered ELP hydrogel was used to encapsulate organ of Corti isolated from neonatal mice. Cultured cochleae were immunostained for markers of hair cells and supporting cells. Organ of Corti hair cell and supporting cell density and organ dimensions were compared between the ELP and nonencapsulated systems. These culture systems were then compared with noncultured cochlea. Results After 3 days in vitro, vital dye uptake and immunostaining for sensory and nonsensory cells show that encapsulated cochlea contain viable cells with an organized architecture. In comparison with nonencapsulated cultured cochlea, ELP-encapsulated cochleae exhibit higher densities of hair cells and supporting cells and taller and narrower organ of Corti dimensions that more closely resemble those of noncultured cochleae. However, we found compromised cell viability when the culture period extended beyond 3 days. Conclusion We conclude that the ELP hydrogel can help preserve the 3-D architecture of neonatal cochlea in short-term culture, which may be applicable to in vitro study of the physiology and pathophysiology of the inner ear. PMID:25111520

  3. Transforming growth factor alpha treatment alters intracellular calcium levels in hair cells and protects them from ototoxic damage in vitro.

    PubMed

    Staecker, H; Dazert, S; Malgrange, B; Lefebvre, P P; Ryan, A F; Van de Water, T R

    1997-07-01

    To determine if transforming growth factor alpha (TGF alpha) pretreatment protects hair cells from aminoglycoside induced injury by modifying their intracellular calcium concentration, we assayed hair cell calcium levels in organ of Corti explants both before and after aminoglycoside (i.e. neomycin, 10(-3) M) exposure either with or without growth factor pretreatment. After TGF alpha (500 ng/ml) treatment, the intracellular calcium level of hair cells showed a five-fold increase as compared to the levels observed in the hair cells of control cultures. After ototoxin exposure, calcium levels in hair cells of control explants showed an increase relative to their baseline levels, while in the presence of growth factors pretreatment, hair cells showed a relative reduction in calcium levels. Pretreatment of organ of Corti explants afforded significant protection of hair cell stereocilia bundle morphology from ototoxic damage when compared to explants exposed to ototoxin alone. This study correlates a rise in hair cell calcium levels with the otoprotection of hair cells by TGF alpha in organ of Corti explants. PMID:9263032

  4. Whole Mount Dissection and Immunofluorescence of the Adult Mouse Cochlea.

    PubMed

    Montgomery, Scott C; Cox, Brandon C

    2016-01-01

    The organ of Corti, housed in the cochlea of the inner ear, contains mechanosensory hair cells and surrounding supporting cells which are organized in a spiral shape and have a tonotopic gradient for sound detection. The mouse cochlea is approximately 6 mm long and often divided into three turns (apex, middle, and base) for analysis. To investigate cell loss, cell division, or mosaic gene expression, the whole mount or surface preparation of the cochlea is useful. This dissection method allows visualization of all cells within the organ of Corti when combined with immunostaining and confocal microscopy to image cells at different planes in the z-axis. Multiple optical cross-sections can also be obtained from these z-stack images. In addition, the whole mount dissection method can be used for scanning electron microscopy, although a different fixation method is needed. Here, we present a method to isolate the organ of Corti as three intact cochlear turns (apex, middle, and base). This method can be used for mice ranging from one week of age through adulthood and differs from the technique used for neonatal samples where calcification of the cochlea is incomplete. A slightly modified version can be used for dissection of the rat cochlea. We also demonstrate a procedure for immunostaining with fluorescently tagged antibodies. PMID:26779585

  5. Reinnervation of Hair Cells by Auditory Neurons after Selective Removal of Spiral Ganglion Neurons

    PubMed Central

    Martinez-Monedero, Rodrigo; Corrales, C. Eduardo; Cuajungco, Math P.; Heller, Stefan; Edge, Albert S.B.

    2007-01-01

    Hearing loss can be caused by primary degeneration of spiral ganglion neurons or by secondary degeneration of these neurons after hair cell loss. The replacement of auditory neurons would be an important step in any attempt to restore auditory function in patients with damaged inner ear neurons or hair cells. Application of β-bungarotoxin, a toxin derived from snake venom, to an explant of the cochlea eradicates spiral ganglion neurons while sparing the other cochlear cell types. The toxin was found to bind to the neurons and to cause apoptotic cell death without affecting hair cells or other inner ear cell types as indicated by TUNEL staining, and, thus, the toxin provides a highly specific means of deafferentation of hair cells. We therefore used the denervated organ of Corti for the study of neuronal regeneration and synaptogenesis with hair cells and found that spiral ganglion neurons obtained from the cochlea of an untreated newborn mouse reinnervated hair cells in the toxin-treated organ of Corti and expressed synaptic vesicle markers at points of contact with hair cells. These findings suggest that it may be possible to replace degenerated neurons by grafting new cells into the organ of Corti. PMID:16408287

  6. Increase in number of helminth species from Dutch red foxes over a 35-year period

    PubMed Central

    2014-01-01

    Background The red fox (Vulpes vulpes) is host to a community of zoonotic and other helminth species. Tracking their community structure and dynamics over decades is one way to monitor the long term risk of parasitic infectious diseases relevant to public and veterinary health. Methods We identified 17 helminth species from 136 foxes by mucosal scraping, centrifugal sedimentation/flotation and the washing and sieving technique. We applied rarefaction analysis to our samples and compared the resulting curve to the helminth community reported in literature 35 years ago. Results Fox helminth species significantly increased in number in the last 35 years (p-value <0.025). Toxascaris leonina, Mesocestoides litteratus, Trichuris vulpis and Angiostrongylus vasorum are four new veterinary-relevant species. The zoonotic fox tapeworm (E. multilocularis) was found outside the previously described endemic regions in the Netherlands. Conclusions Helminth fauna in Dutch red foxes increased in biodiversity over the last three decades. PMID:24708710

  7. [The raccoon roundworm (Baylisascaris procyonis)--no zoonotic risk for Brandenburg?].

    PubMed

    Schwarz, Sabine; Sutor, Astrid; Mattis, Roswitha; Conraths, Franz Josef

    2015-01-01

    The aim of the present study was to investigate the presence of the raccoon roundworm (Baylisascaris [B.] procyonis), a dangerous zoonotic pathogen for humans, in raccoons living in the federal state of Brandenburg, Germany. In the years 2008 to 2013, a total of 762 raccoons, dating from hunting bags, were examined for intestinal helminths. No raccoon roundworm specimen was detected, but 27 samples were positive for Mesocestoides spp. Earlier studies had proved the presence of B. procyonis in Hesse and since 2005 the parasite has also been found in the western part of Saxony-Anhalt. The migration ability of raccoons may promote a further distribution of this parasite and could increase the risk for zoonotic infections in humans. PMID:25876283

  8. A new species of Spinicauda (Nematoda: Heterakidae) and other endoparasites in Platymantis pelewensis (Anura: Ranidae) from the Palau Islands, Republic of Belau, Oceanica.

    PubMed

    Bursey, Charles R; Goldberg, Stephen R

    2004-12-01

    Spinicauda fisheri n. sp. from the intestine of Platymantis pelewensis collected in the Palau Islands, Republic of Belau, is described and illustrated. Spinicauda fisheri represents the 12th species assigned to the genus and the first from Oceanica. It is most similar to Spinicauda spinicauda in that the tail ends in a filament, but it has 19 pairs of caudal papillae as compared with 5 pairs in S. spinicauda. In addition to S. fisheri, 2 species of Cestoda, cysticercoids of Joyeuxiella sp. and tetrathyridia of Mesocestoides sp., 2 species of Nematoda, Oswaldocruzia bakeri and Physocephalus sp. (larvae in cysts), 1 species of Acanthocephala, Acanthocephalus bufonis, and 1 species of Pentastomida, nymphs of Kiricephalus pattoni were identified. PMID:15715239

  9. Data on the parasitological status of golden jackal (Canis aureus L., 1758) in Hungary.

    PubMed

    Takács, András; Szabó, László; Juhász, Lajos; Takács, András Attila; Lanszki, József; Takács, Péter Tamás; Heltai, Miklós

    2014-03-01

    In Hungary, twenty Canis aureus individuals were submitted to parasitological examinations in 2010-2012. Two Coccidia: Cystoisospora canis (15%) and Toxoplasma-type oocysts (5%), one Trematoda: Alaria alata (10%), six Cestoda: Mesocestoides lineatus (20%), Echinococcus granulosus (10%), Dipylidium caninums (5%), Taenia hydatigena (15%), Taenia pisiformis (20%), Taenia crassiceps (40%), and nine Nematoda: Angiostrongylus vasorum (10%), Crenosoma vulpis (30%), Capillaria aerophila (5%), Toxocara canis (20%), Toxascaris leonina (15%), Trichuris vulpis (10%), Ancylostoma caninum (45%), Uncinaria stenocephala (40%), Capillaria plica (45%) have been identified. Angiostronglyus vasorum has been reported from carnivores in Europe, Africa, South America and North America. The helminth A. vasorum or French heartworm is a metastrongylid nematode, widely distributed in Western Europe, that infects the pulmonary arterial tree of dogs, various species of foxes, wolves, Eurasian badgers, coyotes and stoats. To our knowledge, this is the first report of natural A. vasorum infection in golden jackal. PMID:24334089

  10. Helminths of foxes and other wild carnivores from rural areas in Greece.

    PubMed

    Papdopoulos, H; Himonas, C; Papazahariadou, M; Antoniadou-Sotiriadou, K

    1997-09-01

    Twenty species of helminth parasites were identified from fox, wolf, jackal and wild cat material collected in Greece. Of the 314 foxes (Vulpes vulpes) examined, 18 helminth species were recovered comprising one trematode, eight cestodes, seven nematodes and two acanthocephalans, with the cestode species Mesocestoides sp. (73.2%), Joyeuxiella echinorhynchoides (24.5%) and the nematode species Uncinaria stenocephala (43.9%), and Toxara canis (28.6%) being the most prevalent. Five cestode and three nematode species were reported from six wolves (CaniS lupus), together with one trematode, three cestode and four nematode species from five jackals (Canis aureus) and two cestode and three nematode species from four wild cats (Felis silvestris) examined. The species J. echinorhynchoides, Taenia crassiceps and Onicola canis and the genera Spirometra, Rictularia and Pachysentis are reported here for the first time in Greece. The results are discussed in the light of the feeding characteristics of wild carnivores in rural areas of Greece. PMID:9705680

  11. Helminth parasites of the Mediterranean gecko, Hemidactylus turcicus (Sauria: Gekkonidae), from Texas, United States with a summary of helminths of this host.

    PubMed

    McAllister, Chris T; Bursey, Charles R

    2016-09-01

    One hundred-thirty six Mediterranean geckos, Hemidactylus turcicus, were collected between December 1986 and March 2016 in Hardin (n = 7), Harris (n = 57), and Tom Green (n = 72) counties, Texas, USA., and examined for helminth parasites. Fifty-two H. turcicus (38%) were infected with at least one helminth species. Found were a trematode, Mesocoelium meggitti, three cestodes, Mesocestoides sp. (tetrathyridia), Oochoristica ameivae and Oochoristica scelopori, and four nematodes, Cosmocercoides variabilis, Oswaldocruzia pipiens, Parapharyngodon cubensis, and larvae of Physaloptera sp. Oochoristica ameivae, O. scelopori, P. cubensis, Physaloptera sp., and Os. pipiens represent new host records for H. turcicus and M. meggitti is reported from Texas for the first time. A summary of the helminth parasites of both native and non-native H. turcicus is presented. PMID:27447223

  12. Thyroid hormone receptor orthologues from invertebrate species with emphasis on Schistosoma mansoni

    PubMed Central

    Wu, Wenjie; Niles, Edward G; LoVerde, Philip T

    2007-01-01

    Background: Thyroid hormone receptors (TRs) function as molecular switches in response to thyroid hormone to regulate gene transcription. TRs were previously believed to be present only in chordates. Results: We isolated two TR genes from the Schistosoma mansoni and identified TR orthologues from other invertebrates: the platyhelminths, S. japonium and Schmidtea mediterranea, the mollusc, Lottia gigantean and the arthropod Daphnia pulex. Phylogenetic analysis of the DNA binding domain and/or ligand binding domain shows that invertebrate and vertebrate TRs cluster together, TRs from the vertebrates and from the jawless vertebrate (lamprey) clustered within separate subgroups, Platyhelminth TRs cluster outside of the vertebrate TR subgroups and that the schistosome TRs and S. mediterranea TRs clustered within separate subgroups. Alignment of the C-terminus of the A/B domain revealed a conserved TR-specific motif, termed TR 'N-terminus signature sequence', with a consensus sequence of (G/P)YIPSY(M/L)XXXGPE(D/E)X. Heterodimer formation between S. mansoni TRs and SmRXR1 suggests that the invertebrate TR protein gained the ability to form a heterodimer with RXR. ESMA analysis showed that SmTRα could bind to a conserved DNA core motif as a monomer or homodimer. Conclusion: Vertebrate TR genes originated from a common ancestor of the Bilateria. TR genes underwent duplication independently in the Protostomia and Deuterostomia. The duplication of TRs in deuterostomes occurred after the split of jawless and jawed vertebrates. In protostomes, TR genes underwent duplication in Platyhelminths, occurring independently in trematode and turbellarian lineages. Using S. mansoni TRs as an example, invertebrate TRs exhibited the ability to form a dimer with RXR prior to the emergence of the vertebrate TRs and were able to bind to vertebrate TR core DNA elements as a monomer or homodimer. PMID:17727708

  13. Developmental diversity in free-living flatworms

    PubMed Central

    2012-01-01

    Flatworm embryology has attracted attention since the early beginnings of comparative evolutionary biology. Considered for a long time the most basal bilaterians, the Platyhelminthes (excluding Acoelomorpha) are now robustly placed within the Spiralia. Despite having lost their relevance to explain the transition from radially to bilaterally symmetrical animals, the study of flatworm embryology is still of great importance to understand the diversification of bilaterians and of developmental mechanisms. Flatworms are acoelomate organisms generally with a simple centralized nervous system, a blind gut, and lacking a circulatory organ, a skeleton and a respiratory system other than the epidermis. Regeneration and asexual reproduction, based on a totipotent neoblast stem cell system, are broadly present among different groups of flatworms. While some more basally branching groups - such as polyclad flatworms - retain the ancestral quartet spiral cleavage pattern, most flatworms have significantly diverged from this pattern and exhibit unique strategies to specify the common adult body plan. Most free-living flatworms (i.e. Platyhelminthes excluding the parasitic Neodermata) are directly developing, whereas in polyclads, also indirect developers with an intermediate free-living larval stage and subsequent metamorphosis are found. A comparative study of developmental diversity may help understanding major questions in evolutionary biology, such as the evolution of cleavage patterns, gastrulation and axial specification, the evolution of larval types, and the diversification and specialization of organ systems. In this review, we present a thorough overview of the embryonic development of the different groups of free-living (turbellarian) platyhelminths, including the Catenulida, Macrostomorpha, Polycladida, Lecithoepitheliata, Proseriata, Bothrioplanida, Rhabdocoela, Fecampiida, Prolecithophora and Tricladida, and discuss their main features under a consensus phylogeny

  14. Phylogenetic Analysis of the Endoribonuclease Dicer Family

    PubMed Central

    Gao, Zeqian; Wang, Miao; Blair, David; Zheng, Yadong; Dou, Yongxi

    2014-01-01

    Dicers are proteins of the ribonuclease III family with the ability to process dsRNA, involved in regulation of gene expression at the post-transcriptional level. Dicers are conserved from basal metazoans to higher metazoans and contain a number of functional domains that interact with dsRNA. The completed genome sequences of over 34 invertebrate species allowed us to systematically investigate Dicer genes over a diverse range of phyla. The majority of invertebrate Dicers clearly fell into the Dicer1 or Dicer2 subfamilies. Most nematodes possessed only one Dicer gene, a member of the Dicer1 subfamily, whereas two Dicer genes (Dicer1 and Dicer2) were present in all platyhelminths surveyed. Analysis of the key domains showed that a 5′ pocket was conserved across members of the Dicer1 subfamily, with the exception of the nematode Bursaphelenchus xylophilus. Interestingly, Nematostella vectensis DicerB grouped into Dicer2 subfamily harbored a 5′ pocket, which is commonly present in Dicer1. Similarly, the 3′ pocket was also found to be conserved in all Dicer proteins with the exceptions of Schmidtea mediterranea Dicer2 and Trichoplax adherens Dicer A. The loss of catalytic residues in the RNase III domain was noted in platyhelminths and cnidarians, and the ‘ball’ and ‘socket’ junction between two RNase III domains in platyhelminth Dicers was different from the canonical junction, suggesting the possibility of different conformations. The present data suggest that Dicers might have duplicated and diversified independently, and have evolved for various functions in invertebrates. PMID:24748168

  15. Endoparasites of some economically important food fishes of River Jhelum, Kashmir (India).

    PubMed

    Farooq, Taqdees; Khan, Imran; Tak, Irfan-Ur-Rauf; Dar, Shoaib Ali; Yousuf, A R

    2016-09-01

    During the present study endo-parasitic fauna of fish at different sites of River Jhelum were analysed. Four different species of endoparasites were recovered from Schizothorax species which include Adenoscolex kashmirensis Mehra, 1930, Bothriocephalus acheilognathi Yamaguti, 1934, Echinorhynchus sp., Pomphorhynchus kashmirensis Kaw, 1941, belong to Phylum Platyhelminths and Phylum Acanthocephala. Prevalence and generation time were inversely proportional to each other. Prevalence and mean abundance were highest at Qamarwari. Diversity was more at Tengpora. Cestodes including Adenoscolex kashmirensis and Bothriocephalus acheilognathi were more dominant than Pomphorhynchus kashmirensis and Echinorhynchus sp. PMID:27605799

  16. Neurobehavioral toxicity of cadmium sulfate to the planarian Dugesia dorotocephala

    SciTech Connect

    Grebe, E.; Schaeffer, D.J. )

    1991-05-01

    The authors are developing bioassays which use planarians (free-living platyhelminthes) for the rapid determination of various types of toxicity, including acute mortality, tumorigenicity, and short-term neurobehavioral responses. Their motivation for using these animals is due to their importance as components of the aquatic ecology of unpolluted streams their sensitivity to low concentrations of environmental toxicants and the presence of a sensitive neurological system with a true brain which allows for complex social behavior. A previous paper described the results of a neurobehavioral bioassay using phenol in a crossover study. This paper reports a similar crossover study using cadmium sulfate.

  17. Phylogeny of protostome worms derived from 18S rRNA sequences.

    PubMed

    Winnepenninckx, B; Backeljau, T; De Wachter, R

    1995-07-01

    The phylogenetic relationships of protostome worms were studied by comparing new complete 18S rRNA sequences of Vestimentifera, Pogonophora, Sipuncula, Echiura, Nemertea, and Annelida with existing 18S rRNA sequences of Mollusca, Arthropoda, Chordata, and Platyhelminthes. Phylogenetic trees were inferred via neighbor-joining and maximum parsimony analyses. These suggest that (1) Sipuncula and Echiura are not sister groups; (2) Nemertea are protostomes; (3) Vestimentifera and Pogonophora are protostomes that have a common ancestor with Echiura; and (4) Vestimentifera and Pogonophora are a monophyletic clade. PMID:7659019

  18. Phylogenetic relationships among higher Nemertean (Nemertea) Taxa inferred from 18S rDNA sequences.

    PubMed

    Sundberg, P; Turbeville, J M; Lindh, S

    2001-09-01

    We estimated the phylogenetic relationships of 15 nemertean (phylum Nemertea) species from the four subclasses Hoplo-, Hetero-, Palaeo-, and Bdellonemertea with 18S rDNA sequence data. Three outgroup taxa were used for rooting: Annelida, Platyhelminthes, and Mollusca. Parsimony and maximum-likelihood analyses supported the monophyletic status of the Heteronemertea and a taxon consisting of hoplonemerteans and Bdellonemertea, while indicating that Palaeonemertea is paraphyletic. The monophyletic status of the two nemertean classes Anopla and Enopla is not supported by the data. The unambiguous clades are well supported, as assessed by a randomization test (bootstrapping) and branch support values. PMID:11527461

  19. Molecular phylogeny of metazoan intermediate filament proteins.

    PubMed

    Erber, A; Riemer, D; Bovenschulte, M; Weber, K

    1998-12-01

    We have cloned cytoplasmic intermediate filament (IF) proteins from a large number of invertebrate phyla using cDNA probes, the monoclonal antibody IFA, peptide sequence information, and various RT-PCR procedures. Novel IF protein sequences reported here include the urochordata and nine protostomic phyla, i.e., Annelida, Brachiopoda, Chaetognatha, Echiura, Nematomorpha, Nemertea, Platyhelminthes, Phoronida, and Sipuncula. Taken together with the wealth of data on IF proteins of vertebrates and the results on IF proteins of Cephalochordata, Mollusca, Annelida, and Nematoda, two IF prototypes emerge. The L-type, which includes 35 sequences from 11 protostomic phyla, shares with the nuclear lamins the long version of the coil 1b subdomain and, in most cases, a homology segment of some 120 residues in the carboxyterminal tail domain. The S-type, which includes all four subfamilies (types I to IV) of vertebrate IF proteins, lacks 42 residues in the coil 1b subdomain and the carboxyterminal lamin homology segment. Since IF proteins from all three phyla of the chordates have the 42-residue deletion, this deletion arose in a progenitor prior to the divergence of the chordates into the urochordate, cephalochordate, and vertebrate lineages, possibly already at the origin of the deuterostomic branch. Four phyla recently placed into the protostomia on grounds of their 18S rDNA sequences (Brachiopoda, Nemertea, Phoronida, and Platyhelminthes) show IF proteins of the L-type and fit by sequence identity criteria into the lophotrochozoic branch of the protostomia. PMID:9847417

  20. Schistosome sex matters: a deep view into gonad-specific and pairing-dependent transcriptomes reveals a complex gender interplay.

    PubMed

    Lu, Zhigang; Sessler, Florian; Holroyd, Nancy; Hahnel, Steffen; Quack, Thomas; Berriman, Matthew; Grevelding, Christoph G

    2016-01-01

    As a key event for maintaining life cycles, reproduction is a central part of platyhelminth biology. In case of parasitic platyhelminths, reproductive processes can also contribute to pathology. One representative example is the trematode Schistosoma, which causes schistosomiasis, an infectious disease, whose pathology is associated with egg production. Among the outstanding features of schistosomes is their dioecious lifestyle and the pairing-dependent differentiation of the female gonads which finally leads to egg synthesis. To analyze the reproductive biology of Schistosoma mansoni in-depth we isolated complete ovaries and testes from paired and unpaired schistosomes for comparative RNA-seq analyses. Of >7,000 transcripts found in the gonads, 243 (testes) and 3,600 (ovaries) occurred pairing-dependently. Besides the detection of genes transcribed preferentially or specifically in the gonads of both genders, we uncovered pairing-induced processes within the gonads including stem cell-associated and neural functions. Comparisons to work on neuropeptidergic signaling in planarian showed interesting parallels but also remarkable differences and highlights the importance of the nervous system for flatworm gonad differentiation. Finally, we postulated first functional hints for 235 hypothetical genes. Together, these results elucidate key aspects of flatworm reproductive biology and will be relevant for basic as well as applied, exploitable research aspects. PMID:27499125

  1. Schistosome sex matters: a deep view into gonad-specific and pairing-dependent transcriptomes reveals a complex gender interplay

    PubMed Central

    Lu, Zhigang; Sessler, Florian; Holroyd, Nancy; Hahnel, Steffen; Quack, Thomas; Berriman, Matthew; Grevelding, Christoph G.

    2016-01-01

    As a key event for maintaining life cycles, reproduction is a central part of platyhelminth biology. In case of parasitic platyhelminths, reproductive processes can also contribute to pathology. One representative example is the trematode Schistosoma, which causes schistosomiasis, an infectious disease, whose pathology is associated with egg production. Among the outstanding features of schistosomes is their dioecious lifestyle and the pairing-dependent differentiation of the female gonads which finally leads to egg synthesis. To analyze the reproductive biology of Schistosoma mansoni in-depth we isolated complete ovaries and testes from paired and unpaired schistosomes for comparative RNA-seq analyses. Of >7,000 transcripts found in the gonads, 243 (testes) and 3,600 (ovaries) occurred pairing-dependently. Besides the detection of genes transcribed preferentially or specifically in the gonads of both genders, we uncovered pairing-induced processes within the gonads including stem cell-associated and neural functions. Comparisons to work on neuropeptidergic signaling in planarian showed interesting parallels but also remarkable differences and highlights the importance of the nervous system for flatworm gonad differentiation. Finally, we postulated first functional hints for 235 hypothetical genes. Together, these results elucidate key aspects of flatworm reproductive biology and will be relevant for basic as well as applied, exploitable research aspects. PMID:27499125

  2. sine oculis in basal Metazoa.

    PubMed

    Bebenek, Ilona G; Gates, Ruth D; Morris, Joshua; Hartenstein, Volker; Jacobs, David K

    2004-07-01

    We report the recovery of homologs of Six1/2/sine oculis (so), a homeodomain-containing member of the Six-gene family, from a diverse set of basal Metazoa, including representatives of the poriferan classes Demospongia, Calcarea and Hexactinellida, the cnidarian classes Hydrozoa, Scyphozoa and Anthozoa, as well as a ctenophore. so sequences were also recovered from a platyhelminth, an echiurid and two bivalve molluscs, members of the super-phyletic group Lophotrochozoa. In the case of the platyhelminth, multiple distinct so sequences were recovered, as well as a member of the related group Six4/5/D-Six4. Extended sequences of the so gene were recovered from the demosponge, Haliclona sp., and the scyphozoan Aurelia aurita via PCR, and 3' RACE. The affinities of all recovered sequences were assessed using a parsimony analysis based on both nucleic and amino acid sequence and using successive character weighting. Our results indicate that so is highly conserved across the animal kingdom. Preliminary expression data for Aurelia reveal that transcripts of the so homolog are present in the manubrium as well as in the rhopalia, which contain the statocyst and eyes, in the free-swimming ephyra and juvenile stages of these jellyfish. PMID:15221378

  3. Structural analysis of the α subunit of Na(+)/K(+) ATPase genes in invertebrates.

    PubMed

    Thabet, Rahma; Rouault, J-D; Ayadi, Habib; Leignel, Vincent

    2016-01-01

    The Na(+)/K(+) ATPase is a ubiquitous pump coordinating the transport of Na(+) and K(+) across the membrane of cells and its role is fundamental to cellular functions. It is heteromer in eukaryotes including two or three subunits (α, β and γ which is specific to the vertebrates). The catalytic functions of the enzyme have been attributed to the α subunit. Several complete α protein sequences are available, but only few gene structures were characterized. We identified the genomic sequences coding the α-subunit of the Na(+)/K(+) ATPase, from the whole-genome shotgun contigs (WGS), NCBI Genomes (chromosome), Genomic Survey Sequences (GSS) and High Throughput Genomic Sequences (HTGS) databases across distinct phyla. One copy of the α subunit gene was found in Annelida, Arthropoda, Cnidaria, Echinodermata, Hemichordata, Mollusca, Placozoa, Porifera, Platyhelminthes, Urochordata, but the nematodes seem to possess 2 to 4 copies. The number of introns varied from 0 (Platyhelminthes) to 26 (Porifera); and their localization and length are also highly variable. Molecular phylogenies (Maximum Likelihood and Maximum Parsimony methods) showed some clusters constituted by (Chordata/(Echinodermata/Hemichordata)) or (Plathelminthes/(Annelida/Mollusca)) and a basal position for Porifera. These structural analyses increase our knowledge about the evolutionary events of the α subunit genes in the invertebrates. PMID:26812300

  4. Spliced-leader trans-splicing in freshwater planarians.

    PubMed

    Zayas, Ricardo M; Bold, Tyler D; Newmark, Phillip A

    2005-10-01

    trans-Splicing, in which a spliced-leader (SL) RNA is appended to the most 5' exon of independently transcribed pre-mRNAs, has been described in a wide range of eukaryotes, from protozoans to chordates. Here we describe trans-splicing in the freshwater planarian Schmidtea mediterranea, a free-living member of the phylum Platyhelminthes. Analysis of an expressed sequence tag (EST) collection from this organism showed that over 300 transcripts shared one of two approximately 35-base sequences (Smed SL-1 and SL-2) at their 5' ends. Examination of genomic sequences encoding representatives of these transcripts revealed that these shared sequences were transcribed elsewhere in the genome. RNA blot analysis, 5' and 3' rapid amplification of cDNA ends, as well as genomic sequence data showed that 42-nt SL sequences were derived from small RNAs of approximately 110 nt. Similar sequences were also found at the 5' ends of ESTs from the planarian Dugesia japonica. trans-Splicing has already been described in numerous representatives of the phylum Platyhelminthes (trematodes, cestodes, and polyclads); its presence in two representatives of the triclads supports the hypothesis that this mode of RNA processing is ancestral within this group. The upcoming complete genome sequence of S. mediterranea, combined with this animal's experimental accessibility and susceptibility to RNAi, provide another model organism in which to study the function of the still-enigmatic trans-splicing. PMID:15972844

  5. Variation in worm assemblages associated with Pomacea canaliculata (Caenogastropoda, Ampullariidae) in sites near the Río de la Plata estuary, Argentina.

    PubMed

    Damborenea, C; Brusa, E; Paola, A

    2006-12-01

    Pomacea canaliculata is a common gastropod in freshwater habitats from Central and Northern Argentina, extending northwards into the Amazon basin. Several Platyhelminthes have been reported associated to P. canaliculata, sharing an intimate relationship with this gastropod host. The objectives of this study were to describe the symbiotic species assemblages associated to P. canaliculata in the study area, and to disclose differences among them. Samples were taken in three typical small streams and one artificial lentic lagoon, all connected with the Rio de la Plata estuary. The 81.53% were infested with different symbiotic (sensu lato) species. Among the Platyhelminthes, the commensal Temnocephala iheringi Haswell, 1893 was highly prevalent in all samples, always in the mantle cavity. Four trematode taxa were recognized: (a) metacercariae of Echinostoma parcespinosum Lutz, 1924 in the mantle cavity and sporocysts in the digestive gland; (b) metacercariae of Dietziella egregia (Dietz, 1909) in the pericardial cavity; (c) unidentified xiphidiocercariae and (d) unidentified sporocysts and furcocercariae in the digestive gland. Nematode larvae and oligochaetes were found in two localities in the mantle cavity. Among the Annelida, Helobdella ampullariae Ringuelet, 1945 was found in the mantle cavity and lung of snails only from one locality. Our results show that although some of the symbionts are present in all localities, others are restricted to some particular ones, whether in their absolute numbers or in their relative abundance. Thus, each hosting population at the studied localities may be defined by the particular combination of symbionts that bears. PMID:17375466

  6. Deficiency of Angulin-2/ILDR1, a Tricellular Tight Junction-Associated Membrane Protein, Causes Deafness with Cochlear Hair Cell Degeneration in Mice

    PubMed Central

    Kitajiri, Shin-ichiro; Furuse, Mikio

    2015-01-01

    Tricellular tight junctions seal the extracellular spaces of tricellular contacts, where the vertices of three epithelial cells meet, and are required for the establishment of a strong barrier function of the epithelial cellular sheet. Angulins and tricellulin are known as specific protein components of tricellular tight junctions, where angulins recruit tricellulin. Mutations in the genes encoding angulin-2/ILDR1 and tricellulin have been reported to cause human hereditary deafness DFNB42 and DFNB49, respectively. To investigate the pathogenesis of DFNB42, we analyzed mice with a targeted disruption of Ildr1, which encodes angulin-2/ILDR1. Ildr1 null mice exhibited profound deafness. Hair cells in the cochlea of Ildr1 null mice develop normally, but begin to degenerate by two weeks after birth. Tricellulin localization at tricellular contacts of the organ of Corti in the cochlea was retained in Ildr1 null mice, but its distribution along the depth of tricellular contacts was affected. Interestingly, compensatory tricellular contact localization of angulin-1/LSR was observed in the organ of Corti in Ildr1 null mice although it was hardly detected in the organ of Corti in wild-type mice. The onset of hair cell degeneration in Ildr1 null mice was earlier than that in the reported Tric mutant mice, which mimic one of the tricellulin mutations in DFNB49 deafness. These results indicate that the angulin-2/ILDR1 deficiency causes the postnatal degenerative loss of hair cells in the cochlea, leading to human deafness DFNB42. Our data also suggest that angulin family proteins have distinct functions in addition to their common roles of tricellulin recruitment and that the function of angulin-2/ILDR1 for hearing cannot be substituted by angulin-1/LSR. PMID:25822906

  7. Deficiency of angulin-2/ILDR1, a tricellular tight junction-associated membrane protein, causes deafness with cochlear hair cell degeneration in mice.

    PubMed

    Higashi, Tomohito; Katsuno, Tatsuya; Kitajiri, Shin-Ichiro; Furuse, Mikio

    2015-01-01

    Tricellular tight junctions seal the extracellular spaces of tricellular contacts, where the vertices of three epithelial cells meet, and are required for the establishment of a strong barrier function of the epithelial cellular sheet. Angulins and tricellulin are known as specific protein components of tricellular tight junctions, where angulins recruit tricellulin. Mutations in the genes encoding angulin-2/ILDR1 and tricellulin have been reported to cause human hereditary deafness DFNB42 and DFNB49, respectively. To investigate the pathogenesis of DFNB42, we analyzed mice with a targeted disruption of Ildr1, which encodes angulin-2/ILDR1. Ildr1 null mice exhibited profound deafness. Hair cells in the cochlea of Ildr1 null mice develop normally, but begin to degenerate by two weeks after birth. Tricellulin localization at tricellular contacts of the organ of Corti in the cochlea was retained in Ildr1 null mice, but its distribution along the depth of tricellular contacts was affected. Interestingly, compensatory tricellular contact localization of angulin-1/LSR was observed in the organ of Corti in Ildr1 null mice although it was hardly detected in the organ of Corti in wild-type mice. The onset of hair cell degeneration in Ildr1 null mice was earlier than that in the reported Tric mutant mice, which mimic one of the tricellulin mutations in DFNB49 deafness. These results indicate that the angulin-2/ILDR1 deficiency causes the postnatal degenerative loss of hair cells in the cochlea, leading to human deafness DFNB42. Our data also suggest that angulin family proteins have distinct functions in addition to their common roles of tricellulin recruitment and that the function of angulin-2/ILDR1 for hearing cannot be substituted by angulin-1/LSR. PMID:25822906

  8. Ecological correlates of cortisol levels in two bat species with contrasting feeding habits.

    PubMed

    Lewanzik, Daniel; Kelm, Detlev H; Greiner, Sabine; Dehnhard, Martin; Voigt, Christian C

    2012-05-15

    The immediate release of adrenal glucocorticoids can be crucial for an animal's survival when facing a stressor, but constantly elevated or exceptionally high glucocorticoid levels are usually detrimental for health. Although baseline and maximal secretion of glucocorticoids are regulated within narrow ranges within species, plasma glucocorticoid levels vary largely across vertebrates. We asked what ecological factors affect baseline plasma cortisol levels (CortI) and maximum levels (CortMax) following a physiological challenge through administration of adrenocorticotropic hormone (ACTH). Specifically, we studied whether seasonal fluctuations in food abundance correlate with the capacity of cortisol increases in two phyllostomid bat species with contrasting feeding habits: the sanguinivorous vampire bat (Desmodus rotundus) and the frugivorous short-tailed fruit bat (Carollia perspicillata). Both species coexist in habitats with various levels of seasonality (dry and rainforest). On a seasonal basis, resource abundance is more stable for vampire than for fruit bats, but previous studies suggested that daily foraging success may vary more for vampire than for fruit bats. CortI and CortMax varied seasonally in C. perspicillata from dry and rainforests, with the exception of CortMax in rainforest bats. Although we expected food availability to be stable year-round for vampire bats, we found CortI and CortMax of vampires to be higher during the rainy season than during the dry season. Also, we found CortMax to be higher in vampires from the rainforest than in those from the dry forest. CortMax of vampires were among the highest measured for a free-ranging mammal; a pattern that could be related to the species' vulnerability to starvation. We conclude that food availability modulates cortisol levels in free-ranging species that face seasonally fluctuating resources; in species, however, that benefit from food which is constantly abundant, other factors than food may

  9. Viral vector tropism for supporting cells in the developing murine cochlea.

    PubMed

    Sheffield, Abraham M; Gubbels, Samuel P; Hildebrand, Michael S; Newton, Stephen S; Chiorini, John A; Di Pasquale, Giovanni; Smith, Richard J H

    2011-07-01

    Gene-based therapeutics are being developed as novel treatments for genetic hearing loss. One roadblock to effective gene therapy is the identification of vectors which will safely deliver therapeutics to targeted cells. The cellular heterogeneity that exists within the cochlea makes viral tropism a vital consideration for effective inner ear gene therapy. There are compelling reasons to identify a viral vector with tropism for organ of Corti supporting cells. Supporting cells are the primary expression site of connexin 26 gap junction proteins that are mutated in the most common form of congenital genetic deafness (DFNB1). Supporting cells are also primary targets for inducing hair cell regeneration. Since many genetic forms of deafness are congenital it is necessary to administer gene transfer-based therapeutics prior to the onset of significant hearing loss. We have used transuterine microinjection of the fetal murine otocyst to investigate viral tropism in the developing inner ear. For the first time we have characterized viral tropism for supporting cells following in utero delivery to their progenitors. We report the inner ear tropism and potential ototoxicity of three previously untested vectors: early-generation adenovirus (Ad5.CMV.GFP), advanced-generation adenovirus (Adf.11D) and bovine adeno-associated virus (BAAV.CMV.GFP). Adenovirus showed robust tropism for organ of Corti supporting cells throughout the cochlea but induced increased ABR thresholds indicating ototoxicity. BAAV also showed tropism for organ of Corti supporting cells, with preferential transduction toward the cochlear apex. Additionally, BAAV readily transduced spiral ganglion neurons. Importantly, the BAAV-injected ears exhibited normal hearing at 5 weeks of age when compared to non-injected ears. Our results support the use of BAAV for safe and efficient targeting of supporting cell progenitors in the developing murine inner ear. PMID:21530627

  10. [Ludwig van Beethoven: an autoimmune deafness?].

    PubMed

    Davies, P J

    1995-01-01

    The author reminds us of the great moments of Beethoven's life and of the different stages of his deafness onset, until to last instants. The post-mortem examination, performed by doctor Wagner, and the scientific studies of the remains, during the exhumations, are reported. Beethoven's deafness was clearly a sensorineural impairment and the previously suggested prevalent hypotheses are discussed. A new theory is emphasized, based on modern studies about autoimmune sensorineural hearing losses in relation with chronic inflammatory bowel ailment. Conclusion is that Beethoven's deafness was probably owing to a primary autoimmune degeneration of the organ of Corti, giving rise to atrophy of the auditory nerve. PMID:11615339

  11. Vibration Measurement on Reticular Lamina and Basilar Membrane at Multiple Longitudinal Locations

    NASA Astrophysics Data System (ADS)

    Chen, Fangyi; Zha, Dingjun; Choudhury, Niloy; Fridberger, Anders; Nuttall, Alfred L.

    2011-11-01

    The longitudinal distribution of the organ of Corti vibration is important for both understanding the energy delivery and the timing of the cochlear amplification. Recent development on low coherence interferomtry technique allows measuring vibration inside the cochlea. The reticular lamina (RL) vibration spectrum demonstrates that RL vibration leads the basilar membrane (BM). This phase lead is consistent with the idea that the active process may lead the BM vibration. In this study, measurements on multiple longitudinal locations demonstrated similar phase lead. Results on this study suggests that there may be another longitudinal coupling mechanism inside the cochlea other than the traveling wave on BM.

  12. Activated instability of homogeneous droplet nucleation and growth.

    PubMed

    Uline, Mark J; Corti, David S

    2008-12-21

    For the pure-component supercooled Lennard-Jones vapor, the free energy of forming a droplet with a given particle number and volume is calculated using density-functional theory. In contrast to what was noted in previous studies, the free energy surface beyond the pseudosaddle point no longer exhibits a valley but rather channels the nuclei toward a locus of instabilities, initiating an unstable growth phase. Similar to a previous study of bubble formation in superheated liquids [M. J. Uline and D. S. Corti, Phys. Rev. Lett. 99, 076102 (2007)], a new picture of homogeneous droplet nucleation and growth emerges. PMID:19102538

  13. Mutations in the transcriptional activator EYA4 cause late-onset deafness at the DFNA10 locus.

    PubMed

    Wayne, S; Robertson, N G; DeClau, F; Chen, N; Verhoeven, K; Prasad, S; Tranebjärg, L; Morton, C C; Ryan, A F; Van Camp, G; Smith, R J

    2001-02-01

    We identified Eyes absent 4 (EYA4), a member of the vertebrate Eya family of transcriptional activators, as the causative gene of postlingual, progressive, autosomal dominant hearing loss at the DFNA10 locus. In two unrelated families from Belgium and the USA segregating for deafness at this locus, we found different mutations in EYA4, both of which create premature stop codons. Although EYA proteins interact with members of the SIX and DACH protein families in a conserved network that regulates early embryonic development, this finding shows that EYA4 is also important post-developmentally for continued function of the mature organ of Corti. PMID:11159937

  14. Histopathology of the Human Inner Ear in Alström Syndrome

    PubMed Central

    Nadol, Joseph B.; Marshall, Jan D.; Bronson, Roderick T.

    2015-01-01

    Alström syndrome is an autosomal recessive syndromic genetic disorder caused by mutations in the ALMS1 gene. Sensorineural hearing loss occurs in greater than 85% of patients. Histopathology of the inner ear abnormalities in the human has not previously been fully described. Histopathology of the inner ear in Alström syndrome is presented in two genetically confirmed cases. The predominant histopathologic correlates of the sensorineural loss were degeneration of the organ of Corti, both inner and outer hair cells, degeneration of spiral ganglion cells, and atrophy of the stria vascularis and spiral ligament. PMID:26111748

  15. Infrared neural stimulation (INS) inhibits electrically evoked neural responses in the deaf white cat

    NASA Astrophysics Data System (ADS)

    Richter, Claus-Peter; Rajguru, Suhrud M.; Robinson, Alan; Young, Hunter K.

    2014-03-01

    Infrared neural stimulation (INS) has been used in the past to evoke neural activity from hearing and partially deaf animals. All the responses were excitatory. In Aplysia californica, Duke and coworkers demonstrated that INS also inhibits neural responses [1], which similar observations were made in the vestibular system [2, 3]. In deaf white cats that have cochleae with largely reduced spiral ganglion neuron counts and a significant degeneration of the organ of Corti, no cochlear compound action potentials could be observed during INS alone. However, the combined electrical and optical stimulation demonstrated inhibitory responses during irradiation with infrared light.

  16. Results of parasitological examinations of faecal samples from cats and dogs in Germany between 2003 and 2010.

    PubMed

    Barutzki, Dieter; Schaper, Roland

    2011-08-01

    In a retrospective study, the results of parasitological examinations of faecal samples from 8,560 cats and 24,677 dogs between January 2003 and December 2010 in Germany were analysed. 30.4 % of the examined dogs and 22.8 % of the cats were infected with endoparasites. The examination of the faecal samples from dogs revealed stages of Giardia spp. (18.6 %), Toxocara canis (6.1 %), Toxascaris leonina (0.6 %), Ancylostomatidae (2.2 %), Trichuris vulpis (1.2 %), Capillaria spp. (1.3 %), Crenosoma vulpis (0.4 %), Angiostrongylus vasorum (0.5 %), Taeniidae (0.4 %), Dipylidiidae (< 0.1 %), Mesocestoides spp. (< 0.1 %), Isospora spp. (5.6 %), I. ohioensis-complex (3.9 %), I. canis (2.4 %), Sarcocystis spp. (2.2 %) and Hammondia heydorni/Neospora caninum (0.3 %). Dogs in the age groups up to 3 months and > 3 up to 6 months of age showed significantly higher infection rates with Giardia spp. (37.5 % and 38.2 %, respectively), Toxocara canis (12.0 % and 12.4 %, respectively), Toxascaris leonina (1.1 % and 1.6 %, respectively), Isospora spp. (23.4 % and 11.8 %, respectively), I. ohioensis-complex (15.6 % and 7.2 %, respectively) and I. canis (11.8 % and 5.2 %, respectively) compared to older dogs. In faecal samples from cats, stages of Giardia spp. (12.6 %), Toxocara cati (4.7 %), Toxascaris leonina (0.1 %), Ancylostoma tubaeforme (0.2 %), Aelurostrongylus abstrusus (0.5 %), Capillaria spp. (1.0 %), Taeniidae (0.6 %), Dipylidium caninum (< 0.1 %) Mesocestoides spp. (< 0.1 %), Isospora spp. (6.0 %), I. felis (4.4 %), I. rivolta (2.2 %), Toxoplasma gondii/Hammondia hammondi (0.8 %) and Sarcocystis spp. (0.3 %) were detected. Cats in the age groups up to 3 months and > 3 up to 6 months of age showed significantly higher infection rates with Giardia spp. (19.5 % and 24.0 %, respectively), T. cati (8.1 % and 6.9 %, respectively), Isospora spp. (12.8 % and 8.6 %, respectively), I. felis (10.0 % and 5.9%, respectively) and I. rivolta (4.6 % and 2.9%, respectively) compared to older

  17. Tapeworms.

    PubMed

    Georgi, J R

    1987-11-01

    Dogs and cats become infected with tapeworms by ingesting intermediate hosts that contain encysted juvenile tapeworms called larvae. The dog or cat is said to be the definitive host because it shelters the sexually reproductive, egg-producing stage of the tapeworm. The intermediate hosts, which are vertebrates in the case of Taenia and Mesocestoides and insects in the case of Dipylidium and Hymenolepis, become infected by ingesting unhatched but infective tapeworm eggs discharged in the feces of the dog or cat. The relatively less common Diphyllobothrium and Spirometra tapeworms discharge eggs that are undeveloped when passed in the feces and must fall into water to undergo development to the coracidium stage. Diphyllobothrium and Spirometra may have two or three aquatic intermediate hosts in series. The first of these, a copepod, ingests the free-swimming coracidium or ciliated oncosphere that has hatched from the egg. The final intermediate host containing the larva (plerocercoid) infective for the dog or cat is an aquatic vertebrate (fish, frog, water snake). Thus, dogs and cats become infected with tapeworms by eating uncooked meat or fish or by ingesting certain insects. These intermediate hosts are infected with juvenile tapeworms called larvae, which are the infective form for the dog or cat. The intermediate hosts, in turn, become infected by ingesting tapeworm eggs discharged in the feces of the dog or cat or, in the case of Diphyllobothrium and Spirometra, by ingesting coracidia that have subsequently developed in and hatched from such eggs. By far the most common tapeworms of dogs and cats in North America are D. caninum, T. pisiformis, and T. hydatigena. Therefore, the most common sources of tapeworm infection are, respectively, fleas, wild rabbits, and the uncooked meat and offal of ruminants and swine. Whenever a dose of tapeworm remedy is administered or dispensed, the client should be informed of these potential sources of reinfection. There is

  18. A Transcriptomic Analysis of Echinococcus granulosus Larval Stages: Implications for Parasite Biology and Host Adaptation

    PubMed Central

    Parkinson, John; Wasmuth, James D.; Salinas, Gustavo; Bizarro, Cristiano V.; Sanford, Chris; Berriman, Matthew; Ferreira, Henrique B.; Zaha, Arnaldo; Blaxter, Mark L.; Maizels, Rick M.; Fernández, Cecilia

    2012-01-01

    Background The cestode Echinococcus granulosus - the agent of cystic echinococcosis, a zoonosis affecting humans and domestic animals worldwide - is an excellent model for the study of host-parasite cross-talk that interfaces with two mammalian hosts. To develop the molecular analysis of these interactions, we carried out an EST survey of E. granulosus larval stages. We report the salient features of this study with a focus on genes reflecting physiological adaptations of different parasite stages. Methodology/Principal Findings We generated ∼10,000 ESTs from two sets of full-length enriched libraries (derived from oligo-capped and trans-spliced cDNAs) prepared with three parasite materials: hydatid cyst wall, larval worms (protoscoleces), and pepsin/H+-activated protoscoleces. The ESTs were clustered into 2700 distinct gene products. In the context of the biology of E. granulosus, our analyses reveal: (i) a diverse group of abundant long non-protein coding transcripts showing homology to a middle repetitive element (EgBRep) that could either be active molecular species or represent precursors of small RNAs (like piRNAs); (ii) an up-regulation of fermentative pathways in the tissue of the cyst wall; (iii) highly expressed thiol- and selenol-dependent antioxidant enzyme targets of thioredoxin glutathione reductase, the functional hub of redox metabolism in parasitic flatworms; (iv) candidate apomucins for the external layer of the tissue-dwelling hydatid cyst, a mucin-rich structure that is critical for survival in the intermediate host; (v) a set of tetraspanins, a protein family that appears to have expanded in the cestode lineage; and (vi) a set of platyhelminth-specific gene products that may offer targets for novel pan-platyhelminth drug development. Conclusions/Significance This survey has greatly increased the quality and the quantity of the molecular information on E. granulosus and constitutes a valuable resource for gene prediction on the parasite genome

  19. Quantitative imaging of platinum based on laser ablation-inductively coupled plasma-mass spectrometry to investigate toxic side effects of cisplatin.

    PubMed

    Köppen, C; Reifschneider, O; Castanheira, I; Sperling, M; Karst, U; Ciarimboli, G

    2015-12-01

    This work presents a quantitative bioimaging method for platinum based on laser ablation-inductively coupled plasma-mass spectrometry and its application for a biomedical study concerning toxic side effects of cisplatin. To trace the histopathology back to cisplatin, platinum was localized and quantified in major functional units of testicle, cochlea, kidney, nerve and brain sections from cisplatin treated mice. The direct consideration of the histology enables precise interpretation of the Pt images and the novel quantitative evaluation approach allows significantly more precise investigations than the pure image. For the first time, platinum was detected and quantified in all major injured structures including organ of Corti of cochlea and seminiferous tubule of testicle. In this way, proximal tubule in kidney, Leydig cells in testicle, stria vascularis and organ of Corti in cochlea and nerve fibers in sciatic nerves are confirmed as targets of cisplatin in these organs. However, the accumulation of platinum in almost all investigated structures also raises questions about more complex pathogenesis including direct and indirect interruption of several biological processes. PMID:26477751

  20. Tumor Necrosis Factor-α-Induced Ototoxicity in Mouse Cochlear Organotypic Culture

    PubMed Central

    Wu, Qian; Wang, Guo-Peng; Xie, Jing; Guo, Jing-Ying; Gong, Shu-Sheng

    2015-01-01

    Tumor necrosis factor (TNF)-α is a cytokine involved in acute inflammatory phase reactions, and is the primary upstream mediator in the cochlear inflammatory response. Treatment of the organ of Corti with TNF-α can induce hair cell damage. However, the resulting morphological changes have not been systematically examined. In the present study, cochlear organotypic cultures from neonatal mice were treated with various concentrations and durations of TNF-α to induce inflammatory responses. Confocal microscopy was used to evaluate the condition of hair cells and supporting cells following immunohistochemical staining. In addition, the ultrastructure of the stereocilia bundle, hair cells, and supporting cells were examined by scanning and transmission electron microscopy. TNF-α treatment resulted in a fusion and loss of stereocilia bundles in hair cells, swelling of mitochondria, and vacuolation and degranulation of the endoplasmic reticulum. Disruption of tight junctions between hair cells and supporting cells was also observed at high concentrations. Hair cell loss was preceded by apoptosis of Deiters’ and pillar cells. Taken together, these findings detail the morphological changes in the organ of Corti after TNF-α treatment, and provide an in vitro model of inflammatory-induced ototoxicity. PMID:26000970

  1. Intravenous administration of bone marrow mononuclear cells alleviates hearing loss after transient cochlear ischemia through paracrine effects.

    PubMed

    Takagi, Taro; Yoshida, Tadashi; Okada, Masahiro; Hata, Ryuji; Hato, Naohito; Gyo, Kiyofumi; Hakuba, Nobuhiro

    2014-05-16

    Bone marrow mononuclear cells (BMMCs) are known to enhance recovery from ischemic insults by secreting angiogenic factors and inducing the expression of angiogenic factors from host tissues. Therefore, the transplantation of BMMCs is considered a potential approach to promoting the repair of ischemic damaged organs. Here, we investigated the influence of BMMCs on progressive hair cell degeneration after transient cochlear ischemia in gerbils. Transient cochlear ischemia was produced by extracranial occlusion of the bilateral vertebral arteries immediately before their entry into the transverse foramen of the cervical vertebra. An intravenous injection of BMMCs prevented ischemia-induced hair cell degeneration and ameliorated hearing impairment. A tracking study showed that BMMCs injected into the femoral vein were limited in the spiral artery of the cochlea, suggesting that, although transplanted BMMCs were retained within the spiral ganglion area of the cochlea, they were neither transdifferentiated into cochlear cells nor fused with the injured hair cells and supporting cells in the organ of Corti to restore their functions. We also showed that the protein level of neurotrophin-3 and glial cell line-derived neurotrophic factor in the organ of Corti was upregulated after treatment with BMMCs. These results suggested that BMMCs have therapeutic potential possibly through paracrine effects. Thus, we propose the use of BMMCs as a potential new therapeutic strategy for hearing loss. PMID:24840930

  2. Evaluation of the internal structure of normal and pathological Guinea pig cochleae using optical coherence tomography.

    PubMed

    Kakigi, Akinobu; Takubo, Yuya; Egami, Naoya; Kashio, Akinori; Ushio, Munetaka; Sakamoto, Takashi; Yamashita, Shinji; Yamasoba, Tatsuya

    2013-01-01

    Optical coherence tomography (OCT) makes it possible to visualize the internal structures of several organs, such as the eye, in vivo. Although visualization of the internal structures of the inner ear has been used to try and identify certain pathological conditions, attempts have failed mainly due to the thick bony capsule surrounding this end organ. After decalcifying the bony wall of the cochlea with ethylenediamine tetraacetic acid, we could clearly visualize its internal structures by using OCT. We identified endolymphatic hydrops, strial atrophy and damage to the organ of Corti, evident as a distention of Reissner's membrane, thinning of the lateral wall and flattening of the organ of Corti, respectively. When specimens embedded in paraffin, sliced and stained with hematoxylin and eosin (HE) were examined under a light microscope, the OCT images of normal and pathological cochleae were virtually identical with those of the HE specimens, except that the HE specimens exhibited several artifacts unrecognized in OCT images, which were considered to be induced during the preparation process. Since OCT enables one to obtain arbitrary plane images by manipulating the slice axis of the specimens and avoids any misinterpretation due to artifacts induced during histological preparation, our technique would be useful for examining cochlear pathologies without or prior to histological evaluations. PMID:24107357

  3. Virally-expressed connexin26 restores gap junction function in the cochlea of conditional Gjb2 knockout mice

    PubMed Central

    Yu, Qing; Wang, Yunfeng; Chang, Qing; Wang, Jianjun; Gong, Shushen; Li, Huawei; Lin, Xi

    2013-01-01

    Mutations in GJB2, which codes for the gap junction protein connexin26, are the most common causes of human nonsyndromic hereditary deafness. We inoculated modified adeno-associated viral vectors into the scala media of early postnatal conditional Gjb2 knockout mice to drive exogenous connexin26 expression. We found extensive virally-expressed connexin26 in cells lining the scala media, and intercellular gap junction network was re-established in the organ of Corti of mutant mouse cochlea. Widespread ectopic connexin26 expression neither formed ectopic gap junctions nor affected normal hearing thresholds in wild type mice, suggesting that autonomous cellular mechanisms regulate proper membrane trafficking of exogenously-expressed connexin26 and govern the functional manifestation of them. Functional recovery of gap-junction-mediated coupling among the supporting cells was observed. We found that both cell death in the organ of Corti and degeneration of spiral ganglion neurons in the cochlea of mutant mice were substantially reduced, although auditory brainstem responses did not show significant hearing improvement. This is the first report demonstrating that virally-mediated gene therapy restored extensive gap junction intercellular network among cochlear non-sensory cells in vivo. Such a treatment performed at early postnatal stages resulted in a partial rescue of disease phenotypes in the cochlea of the mutant mice. PMID:24225640

  4. In vivo imaging and vibration measurement of Guinea pig cochlea

    NASA Astrophysics Data System (ADS)

    Choudhury, Niloy; Chen, Fangyi; Zheng, Jiefu; Nuttall, Alfred L.; Jacques, Steven L.

    2008-02-01

    An optical coherence tomography (OCT) system was built to acquire in vivo, both images and vibration measurements of the organ of Corti of the guinea pig. The organ of Corti was viewed through a ~500-μm diameter hole in the bony wall of the scala tympani of the first cochlear turn. In imaging mode, the image was acquired as reflectance R(x,z). In vibration mode, the basilar membrane (BM) or reticular lamina (RL) was selected based on the image. Under software control, the system would move the scanning mirrors to bring the sensing volume of the measurement to the desired tissue location. To address the gain stability problem of the homodyne OCT system, arising from the system moving in and out of the quadrature point and also to resolve the 180 degree ambiguity in the phase measurement using an interferometer, a vibration calibration method is developed by adding a vibrating source to the reference arm to monitor the operating point of the interferometric system. Amplitude gain and phase of various cochlear membranes was measured for different sound pressure level (SPL) varying from 65dB SPL to 93 dB SPL.

  5. Reduced Connexin26 in the Mature Cochlea Increases Susceptibility to Noise-Induced Hearing Lossin Mice.

    PubMed

    Zhou, Xing-Xing; Chen, Sen; Xie, Le; Ji, Yu-Zi; Wu, Xia; Wang, Wen-Wen; Yang, Qi; Yu, Jin-Tao; Sun, Yu; Lin, Xi; Kong, Wei-Jia

    2016-01-01

    Connexin26 (Cx26, encoded by GJB2) mutations are the most common cause of non-syndromic deafness. GJB2 is thought to be involved in noise-induced hearing loss (NIHL). However, the role of Cx26 in NIHL is still obscure. To explore the association between Cx26 and NIHL, we established a Cx26 knockdown (KD) mouse model by conditional knockdown of Cx26 at postnatal day 18 (P18), and then we observed the auditory threshold and morphologic changes in these mice with or without noise exposure. The Cx26 KD mice did not exhibit substantial hearing loss and hair cell degeneration, while the Cx26 KD mice with acoustic trauma experienced higher hearing loss than simple noise exposure siblings and nearly had no recovery. Additionally, extensive outer hair cell loss and more severe destruction of the basal organ of Corti were observed in Cx26 KD mice after noise exposure. These data indicate that reduced Cx26 expression in the mature mouse cochlea may increase susceptibility to noise-induced hearing loss and facilitate the cell degeneration in the organ of Corti. PMID:26927086

  6. Power Efficiency of Outer Hair Cell Somatic Electromotility

    PubMed Central

    Rabbitt, Richard D.; Clifford, Sarah; Breneman, Kathryn D.; Farrell, Brenda; Brownell, William E.

    2009-01-01

    Cochlear outer hair cells (OHCs) are fast biological motors that serve to enhance the vibration of the organ of Corti and increase the sensitivity of the inner ear to sound. Exactly how OHCs produce useful mechanical power at auditory frequencies, given their intrinsic biophysical properties, has been a subject of considerable debate. To address this we formulated a mathematical model of the OHC based on first principles and analyzed the power conversion efficiency in the frequency domain. The model includes a mixture-composite constitutive model of the active lateral wall and spatially distributed electro-mechanical fields. The analysis predicts that: 1) the peak power efficiency is likely to be tuned to a specific frequency, dependent upon OHC length, and this tuning may contribute to the place principle and frequency selectivity in the cochlea; 2) the OHC power output can be detuned and attenuated by increasing the basal conductance of the cell, a parameter likely controlled by the brain via the efferent system; and 3) power output efficiency is limited by mechanical properties of the load, thus suggesting that impedance of the organ of Corti may be matched regionally to the OHC. The high power efficiency, tuning, and efferent control of outer hair cells are the direct result of biophysical properties of the cells, thus providing the physical basis for the remarkable sensitivity and selectivity of hearing. PMID:19629162

  7. Potassium-induced release of an endogenous toxic activity for outer hair cells and auditory neurons in the cochlea: a new pathophysiological mechanism in Menière's disease?

    PubMed

    Lefebvre, P P; Weber, T; Rigo, J M; Delree, P; Leprince, P; Moonen, G

    1990-08-01

    In Menière's disease, the increase of extracellular potassium concentration in the perilymph is thought to play a key role in determining the progressive loss of cochlear hair cells. In this paper, we describe a serum-free culture preparation of hair cells from 5 day-old rat and report the release by the cochlea, in response to an increase of extracellular potassium concentration, of a cytotoxic activity active on hair cells and auditory neurons. The toxic activity is associated with low molecular weight (less than 10,000 Dalton) molecule(s) as revealed by ultrafiltration. Morphological studies performed on the organ of Corti incubated during 24 h in the presence of the cochlea-derived toxic activity (CTA), show that this factor is toxic for hair cells and not for supporting or surrounding cells. The release of CTA occurs both in the spiral ganglion and in the organ of Corti. We suggest that this cochlea-derived toxic activity may play an important role in the pathophysiology of the hearing loss that occurs during the progression of Menière's disease. PMID:2228800

  8. Correct Timing of Proliferation and Differentiation is Necessary for Normal Inner Ear Development and Auditory Hair Cell Viability

    PubMed Central

    Kopecky, Benjamin J.; Jahan, Israt; Fritzsch, Bernd

    2013-01-01

    Background Hearing restoration through hair cell regeneration will require revealing the dynamic interactions between proliferation and differentiation during development to avoid the limited viability of regenerated hair cells. Pax2-Cre N-Myc conditional knockout (CKO) mice highlighted the need of N-Myc for proper neurosensory development and possible redundancy with L-Myc. The late-onset hair cell death in the absence of early N-Myc expression could be due to mis-regulation of genes necessary for neurosensory formation and maintenance, such as Neurod1, Atoh1, Pou4f3, and Barhl1. Results Pax2-Cre N-Myc L-Myc double CKO mice show that proliferation and differentiation are linked together through Myc and in the absence of both Mycs, altered proliferation and differentiation results in morphologically abnormal ears. In particular, the organ of Corti apex is re-patterned into a vestibular-like organization and the base is truncated and fused with the saccule. Conclusions These data indicate that therapeutic approaches to restore hair cells must take into account a dynamic interaction of proliferation and differentiation regulation of basic Helix-Loop-Helix transcription factors in attempts to stably replace lost cochlear hair cells. In addition, our data indicate that Myc is an integral component of the evolutionary transformation process that resulted in the organ of Corti development. PMID:23193000

  9. The MYC Road to Hearing Restoration

    PubMed Central

    Kopecky, Benjamin; Fritzsch, Bernd

    2012-01-01

    Current treatments for hearing loss, the most common neurosensory disorder, do not restore perfect hearing. Regeneration of lost organ of Corti hair cells through forced cell cycle re-entry of supporting cells or through manipulation of stem cells, both avenues towards a permanent cure, require a more complete understanding of normal inner ear development, specifically the balance of proliferation and differentiation required to form and to maintain hair cells. Direct successful alterations to the cell cycle result in cell death whereas regulation of upstream genes is insufficient to permanently alter cell cycle dynamics. The Myc gene family is uniquely situated to synergize upstream pathways into downstream cell cycle control. There are three Mycs that are embedded within the Myc/Max/Mad network to regulate proliferation. The function of the two ear expressed Mycs, N-Myc and L-Myc were unknown less than two years ago and their therapeutic potentials remain speculative. In this review, we discuss the roles the Mycs play in the body and what led us to choose them to be our candidate gene for inner ear therapies. We will summarize the recently published work describing the early and late effects of N-Myc and L-Myc on hair cell formation and maintenance. Lastly, we detail the translational significance of our findings and what future work must be performed to make the ultimate hearing aid: the regeneration of the organ of Corti. PMID:24710525

  10. Reduced Connexin26 in the Mature Cochlea Increases Susceptibility to Noise-Induced Hearing Loss in Mice

    PubMed Central

    Zhou, Xing-Xing; Chen, Sen; Xie, Le; Ji, Yu-Zi; Wu, Xia; Wang, Wen-Wen; Yang, Qi; Yu, Jin-Tao; Sun, Yu; Lin, Xi; Kong, Wei-Jia

    2016-01-01

    Connexin26 (Cx26, encoded by GJB2) mutations are the most common cause of non-syndromic deafness. GJB2 is thought to be involved in noise-induced hearing loss (NIHL). However, the role of Cx26 in NIHL is still obscure. To explore the association between Cx26 and NIHL, we established a Cx26 knockdown (KD) mouse model by conditional knockdown of Cx26 at postnatal day 18 (P18), and then we observed the auditory threshold and morphologic changes in these mice with or without noise exposure. The Cx26 KD mice did not exhibit substantial hearing loss and hair cell degeneration, while the Cx26 KD mice with acoustic trauma experienced higher hearing loss than simple noise exposure siblings and nearly had no recovery. Additionally, extensive outer hair cell loss and more severe destruction of the basal organ of Corti were observed in Cx26 KD mice after noise exposure. These data indicate that reduced Cx26 expression in the mature mouse cochlea may increase susceptibility to noise-induced hearing loss and facilitate the cell degeneration in the organ of Corti. PMID:26927086

  11. The basilar membrane acts as a passive support structure at the cochlear apex

    NASA Astrophysics Data System (ADS)

    Warren, Rebecca L.; Fridberger, Anders

    2015-12-01

    The precise mechanical behavior of the basilar membrane (BM) at low frequencies is still unknown. To address this issue we use an in vitro preparation of the guinea pig temporal bone to investigate the mechanical behaviour of the organ of Corti at the apex of the cochlea. Confocal laser interferometry is used to record the nanometre displacements of both Hensen's cells (HeC) and the BM in response to sound and electrical stimulation. We show that at low frequencies, the BM exhibits greatly reduced sound-evoked movement (˜35dB less) and no current-evoked movement, when compared to the HeC at the same position along the spiral. The BM best frequency is found to be an average of 52Hz (0.35 octave) higher than the HeC best frequency. In addition, we demonstrate that BM motion is not affected by inhibition of somatic electromotility or by blocking the mechanoelectrical transduction channels.We therefore propose that the BM primarily acts as a passive support structure at the cochlear apex. We suggest that the micromechanics of the cochlea that are vital to low-frequency amplification and frequency selectivity take place predominantly at the surface of the organ of Corti.

  12. Filtering of Acoustic Signals within the Hearing Organ

    PubMed Central

    Ramamoorthy, Sripriya; Chen, Fangyi; Jacques, Steven L.; Wang, Ruikang; Choudhury, Niloy; Fridberger, Anders

    2014-01-01

    The detection of sound by the mammalian hearing organ involves a complex mechanical interplay among different cell types. The inner hair cells, which are the primary sensory receptors, are stimulated by the structural vibrations of the entire organ of Corti. The outer hair cells are thought to modulate these sound-evoked vibrations to enhance hearing sensitivity and frequency resolution, but it remains unclear whether other structures also contribute to frequency tuning. In the current study, sound-evoked vibrations were measured at the stereociliary side of inner and outer hair cells and their surrounding supporting cells, using optical coherence tomography interferometry in living anesthetized guinea pigs. Our measurements demonstrate the presence of multiple vibration modes as well as significant differences in frequency tuning and response phase among different cell types. In particular, the frequency tuning at the inner hair cells differs from other cell types, causing the locus of maximum inner hair cell activation to be shifted toward the apex of the cochlea compared with the outer hair cells. These observations show that additional processing and filtering of acoustic signals occur within the organ of Corti before inner hair cell excitation, representing a departure from established theories. PMID:24990925

  13. Finite element cochlea box model - Mechanical and electrical analysis of the cochlea

    NASA Astrophysics Data System (ADS)

    Nikolic, Milica; Teal, Paul D.; Isailovic, Velibor; Filipović, Nenad

    2015-12-01

    The primary role of the cochlea is to transform external sound stimuli into mechanical vibrations and then to neural impulses which are sent to the brain. A simplified cochlea box model was developed using the finite element method. Firstly, a mechanical model of the cochlea was analyzed. The box model consists of the basilar membrane and two fluid chambers - the scala vestibuli and scala tympani. The third chamber, the scala media, was neglected in the mechanical analysis. The best agreement with currently available analytical and experimental results was obtained when behavior of the fluid in the chambers was described using the wave acoustic equation and behavior of the basilar membrane was modeled with Newtonian dynamics. The obtained results show good frequency mapping. The second approach was to use an active model of the cochlea in which the Organ of Corti was included. The operation of the Organ of Corti involves the generation of current, caused by mechanical vibration. This current in turn causes a force applied to the basilar membrane, creating in this way an active feedback mechanism. A state space representation of the electro-mechanical model from existing literature was implemented and a first comparison with the finite element method is presented.

  14. Fecal shedding of Toxocara canis and other parasites in foxes and coyotes on Prince Edward Island, Canada.

    PubMed

    Wapenaar, Wendela; Barkema, Herman W; O'Handley, Ryan

    2013-04-01

    Knowledge of parasites shed by wild canids can assist in recognizing risk to human and domestic animal health. Our aim was to estimate the prevalence of patent infections with Toxocara canis and other parasites in foxes (Vulpes vulpes) and coyotes (Canis latrans) in Prince Edward Island, Canada. Identification of parasite species was based on microscopic examination of feces, with the use of a sucrose fecal flotation method. Sample collection was performed in winter on carcasses of 271 and 185 hunted or trapped foxes and coyotes, respectively. One or more parasite species were observed in 242 (89%) foxes and 128 (69%) coyotes. Toxocara canis, Uncinaria stenocephala, Capillaria spp., Mesocestoides, Taenidd spp., Alaria spp., Cryptocotyle lingua, Sarcocystis spp., Neospora caninum-like coccidia, and other coccidia were identified. A third of juvenile foxes were shedding T. canis and had a high prevalence of Capillaria spp., especially in juvenile foxes (69%). Taenidd eggs, Alaria spp. and Sarcocystis spp. were more common in coyotes (24, 18, and 9%, respectively) than foxes (8, 11, and 1%, respectively). Despite the limitations of fecal flotation to identify parasite species, the high prevalence of T. canis warrants the attention of public health professionals. PMID:23568915

  15. Frequency distributions of helminths of wolves in Kazakhstan.

    PubMed

    Abdybekova, A M; Torgerson, P R

    2012-03-23

    Between 2001 and 2008 a total of 41 wolves (Canis lupus) were necropsied in southern Kazakhstan and their intestinal parasite fauna evaluated. Of these animals 8 (19.5%) were infected with Echinococcus granulosus, 15 (36%) with Taenia spp, 13 (31.7%) with Dypilidium caninum, 5 (12.2%) with Mesocestoides lineatus, 15 (36.6%) with Toxocara canis, 16 (39%) with Toxascaris leonina, 8 (19.5%) with Trichuris vulpis, 9 (22%) with Macracanthorhynchus catulinus and 1 (2.4%) with Moniliformis moniliformis. All parasites had an aggregated distribution which followed a zero inflated or hurdle model. Although a small convenience sample of wolves, the results indicate a high prevalence of infection with E. granulosus. The mean abundance (1275 E. granulosus per wolf) was high with individual infected wolves carrying intensities of several thousand parasites. As wolves are common in Kazakhstan they may act as an important host in the transmission of this zoonotic parasite. The wolves were sampled from an area of Kazakhstan where there is a high prevalence of hydatid cysts in livestock and where echinococcosis has been observed in wild ungulates. PMID:21962968

  16. Intestinal parasites of the red fox (Vulpes vulpes) in Slovenia.

    PubMed

    Vergles Rataj, Aleksandra; Posedi, Janez; Zele, Diana; Vengušt, Gorazd

    2013-12-01

    In the present study, 428 foxes were collected and examined for intestinal helminths using the washing-out method. Parasites were found in 93.2% of the examined animals. The most frequently identified nematodes were Uncinaria stenocephala (58.9%), Toxocara canis (38.3%) and Molineus patens (30.6%). Other nematodes found were Pterygodermatites affinis (4.2%), Capillaria sp. (2.8%), Crenosoma vulpis (2.8%), Toxascaris leonina (2.5%), Trichuris vulpis (0.7%) and Physaloptera sp. (0.2%). Mesocestoides sp. (27.6%) and Taenia crassiceps (22.2%) were the most prevalent cestodes, followed by T. polyacantha (6.5%), Hymenolepis nana (2.1%), T. pisiformis (2.1%) and Dipylidium caninum (1.4%). The study also revealed four trematode species: Rossicotrema donicum (1.6%), Heterophyes heterophyes (1.1%), Metagonimus yokogawai (1.1%), Prohemistomum appendiculatum (0.4%) and two protozoan species: oocysts of Sarcocystis (2.8%) and Isospora (0.4%). This is the first extensive study on the intestinal parasites of the red fox (Vulpes vulpes) in Slovenia. The 2.6% prevalence of Echinococcus multilocularis in the same sample population as investigated herein has been reported previously (Vergles Rataj et al., 2010). PMID:23974942

  17. Field evaluation of the efficacy and safety of emodepside plus praziquantel tablets (Profender tablets for dogs) against naturally acquired nematode and cestode infections in dogs.

    PubMed

    Altreuther, Gertraut; Radeloff, Isabelle; LeSueur, Christophe; Schimmel, Annette; Krieger, Klemens J

    2009-08-01

    A controlled, blinded and randomised multicentre field study evaluated the efficacy and safety of a new anthelmintic tablet formulation containing emodepside plus praziquantel (Profender tablets for dogs) in the treatment of gastrointestinal nematode and cestode infections in dogs in France, Germany, Portugal and Slovakia. Dogs positive for nematodes and/or cestodes (demonstrated by faecal egg counts and/or the presence of proglottids) were treated with emodepside plus praziquantel tablets (n = 239) or the reference product containing milbemycin oxime and praziquantel (Milbemax [n = 115]) at the recommended dose rate. Two faecal samples collected between 7 and 13 days after treatment were evaluated for proglottids, nematode and cestode eggs. No suspected adverse drug reactions were observed in the study. The following parasite species were identified: Trichuris vulpis, Toxocara canis, Toxascaris leonina, Uncinaria stenocephala, Ancylostoma caninum, Dipylidium caninum, Taeniidae and Mesocestoides spp. Geometric mean nematode egg counts in dogs treated with emodepside plus praziquantel tablets were reduced by 99.9 % compared with a reduction of 99.6 % for the reference product. Statistical analysis demonstrated noninferiority of investigational versus reference product (p = 0.0342). None of the dogs treated with emodepside plus praziquantel or reference product remained positive for cestodes after treatment. The study demonstrated that emodepside plus praziquantel tablets are safe and highly efficacious against a broad spectrum of nematodes and cestodes under field conditions. PMID:19575222

  18. Intestinal and lung parasites in owned dogs and cats from central Italy.

    PubMed

    Riggio, Francesca; Mannella, Riccardo; Ariti, Gaetano; Perrucci, Stefania

    2013-03-31

    Prevalence and risk factors of intestinal and lung parasites were investigated in 239 owned dogs and 81 owned cats from central Italy. In 36 dogs and 20 cats found infected by nematodes, pre and post-treatment faecal egg count (FEC) was also evaluated. About 31% of dogs and about 35% of cats resulted positive for at least one intestinal or lung parasitic species. Helminthic, intestinal and zoonotic infections resulted prevalent in examined animals. Examined dogs resulted infected by Toxocara canis (13.0%), Toxascaris leonina (1.7%), Trichuris vulpis (3.3%), Ancylostoma caninum (2.0%), Uncinaria stenocephala (1.25%), Strongyloides stercoralis (0.8%), Angiostrongylus vasorum (0.4%), Dipylidium caninum (1.25%), Taeniidae eggs (0.4%), Giardia duodenalis (3.8%), and Cystoisospora (Isospora) spp. (7.5%). Examined cats were infected by Toxocara cati (22.2%), Capillaria aerophila (1.2%), Ancylostoma tubaeformae (1.2%), U. stenocephala (3.7%), Aelurostrongylus abstrusus (1.2%), Mesocestoides sp. (1.2%), D. caninum (1.2%), G. duodenalis (1.2%) and Cystoisospora spp. (4.5%). The presence of clinical signs and the young age (less than 6 months) were identified as risk factors by univariate and multivariate statistical analysis. In 63.9% treated dogs and in 80.0% treated cats, percentages of post-treatment FEC reduction higher than 90% were found. Results obtained in this study are discussed. PMID:23265188

  19. Wild Red Foxes (Vulpes vulpes) as Sentinels of Parasitic Diseases in the Province of Soria, Northern Spain.

    PubMed

    Lledó, Lourdes; Giménez-Pardo, Consuelo; Saz, José Vicente; Serrano, José Luis

    2015-12-01

    Four hundred red foxes (Vulpes vulpes) were examined for ecto- (arthropods) and endoparasites (Leishmania spp., Trichinella spp., and intestinal parasites). Different species of flea (total prevalence, 40.50%), tick (16.25%), mite (7.25%), and fly (1.50%) were identified. The most prevalent flea was Pulex irritans (found on 29% of the foxes); the most prevalent tick, mite, and fly were Ixodes canisuga (on 5%), Sarcoptes scabiei (on 5.25%), and Hippobosca equina (on 1%), respectively. The endoparasites identified included Leishmania spp. (found in 12% of the foxes), Trichinella spp. (in 15.5%, with T. britovi the most prevalent species in 15.25%), Cestoda (in 72.75%, with Mesocestoides spp. the most prevalent in 69.50%), and intestinal ascarids (in 73.25%, with Ancylostoma caninum the most prevalent in 12.50%). No animal was free of parasites. The present results suggest that foxes can act as sentinels of diseases transmitted by ecto- and endoparasites. PMID:26565688

  20. An epidemiological survey on intestinal helminths of stray dogs in Mashhad, North-east of Iran.

    PubMed

    Emamapour, Seyed Rasoul; Borji, Hassan; Nagibi, Abolghasem

    2015-06-01

    This research was conducted to determine the prevalence of gastrointestinal helminths in stray dogs in the northeast of Iran, with special attention to those parasites that can be transmitted to human. In this experiment, a total of 72 adult and 18 juvenile stray dogs were collected and necropsied for the presence of helminth parasites from October 2011 to August 2012. The overall prevalence of gastrointestinal helminths was 86 % (95 % CI: 79.2-92.8 %). The observed helminths of the gastrointestinal tract were listed as follows: Toxocara canis (29 %), Toxascaris leonina (7 %), Ancylostoma caninum (2 %), Taenia hydatigena (43 %), Dipylidium caninum (39 %), Echinococcus granulosus (38 %), Mesocestoides lineatus (16 %), Taenia multiceps (11 %), Taenia ovis (3 %). There were no significant differences for the prevalence of gastrointestinal helminths between female (83.6 %) and male (89.7 %) and between young (89 %) and adult (72.2 %) animals. However, the prevalence of E. granulosus, T. hydatigena and D. caninum showed an increasing trend with increasing host age, significantly. Based on our data, it is important to point out the presence of zoonotic agents, namely E. granulosus and T. canis in stray dogs in the investigated area. Due to its impact on public health, appropriate control measures should be taken and it is recommended to determine the most appropriate preventive methods. PMID:26064015

  1. Helminth Infections of Stray Dogs from Garmsar, Semnan Province, Central Iran

    PubMed Central

    Eslami, A; Ranjbar-Bahadori, Sh; Meshgi, B; Dehghan, M; Bokaie, S

    2010-01-01

    Background The aim was to study the gastro-intestinal helminths of stray dogs of Garmsar, Semnan Province, Central Iran, and its impacts on human health and animal production. Methods During 2006, the alimentary tracts of 50 stray dogs at necropsy, selected from villages around Garmsar, were removed, and examined for helminth infections. Subsequently helminths were collected from the contents of each part and scraped sample of small intestines of washed materials in a 100-mesh sieve. To identify the species of helminths, the nematodes were cleared in lactophenol and cestodes were stained using carmine acid. Results Mixed infection was the rule and 40 dogs (80%) harbored more than one species of helminth. Taenia hydatigena was the most prevalent species (80%) followed by Echinococcus granulosus (64%), Toxocara canis (22%), Mesocestoides lineatus (12%), Taenia multiceps (10%) and Dipylidium caninum (4%). The mean intensity of worm infection was low (1–3) except for that of E. granulosus (645). No significant difference was noticed between sex, age and most helminth infections except for that of sex and T. hydatigena (P=0.001) as well as age and T. canis (P=0.001). Conclusion Although human infection with T. hydatigena is unlikely, but other helminths reported in this study are of zoonotic importance, and may pose a threat to community health, and reduce the productions of ruminants harboring taeniid metacestodes. PMID:22347264

  2. First detection of Echinococcus multilocularis in dogs in a highly endemic area of Poland.

    PubMed

    Karamon, Jacek; Samorek-Pierog, Malgorzata; Kochanowski, Maciej; Dabrowska, Joanna; Sroka, Jacek; Golab, Elzbieta; Umhang, Gerald; Cencek, Tomasz

    2016-01-01

    The aim of the investigation was to estimate the epizootic situation concerning infection by the cestode Echinococcus multilocularis Leuckart, 1863 in dogs (Canis lupus familiaris Linnaeus) from a Polish region where this parasite is highly prevalent in red foxes. Faecal samples (n = 148) were collected from rural dogs in Podkarpackie Province. Samples were examined through nested PCR (for E. multilocularis), multiplex PCR (E. multilocularis, species of Taenia Linnaeus, 1758) and PCR [E. granulosus (Batsch, 1786)]. Specific products were sequenced. Faeces were also examined coproscopically. In samples from two dogs (1.4%), there were positive PCR results for E. multilocularis. Taenia-specific PCR products were found in nine dogs (6.1%). Sequencing identified Taenia serialis (Gervais, 1847), T. hydatigena Pallas, 1766, T. pisiformis (Bloch, 1780) and Hydatigera taeniaeformis (Batsch, 1786). One sample (0.7%) was identified as Mesocestoides litteratus (Batsch, 1786). All samples were negative for E. granulosus with PCR. Taking into account coproscopic and PCR results, 28% of dogs were infected with helminths (8% with tapeworms). It should be stressed that one of the infected with E. multilocularis dogs shed eggs of the Taenia type and had a habit of preying on rodents. This investigation revealed the presence of E. multilocularis in dogs for the first time in Poland. PMID:27311792

  3. Helminths of the ocelot from southern Texas.

    PubMed

    Pence, Danny B; Tewes, Michael E; Laack, Linda L

    2003-07-01

    In the USA, the ocelot (Leopardus pardalis) is a highly endangered felid found only in a few remaining vestiges of native thornshrub brushland in the Lower Rio Grande Valley (LRGV) of extreme southern Texas. From 1987-1998, carcasses of 15 adult ocelots that died of vehicular accidents or natural causes were examined for helminths. All cats had 1-8 (mean = 3) helminth species. All were infected with 1-101 (mean +/- SE = 32 +/- 7) Toxascaris leonina. Other helminths from these ocelots were Alaria marcianae, Brachylaima sp., Mesocestoides lineatus, Taenia rileyi, Oncicola canis, Dirofilaria immitis, Physaloptera rara, Ancylostoma tubaeformae, Cylicospirura chevreuxi, Vogeloides felis, and Metathelazia californica. Additionally, two cats had scarring of the aorta with lesions typical of those caused by Spriocerca lupi, although larval nematodes were not seen. A clinal variation in size of nearly three orders of magnitude was noted in the diplostomatid trematodes in the small intestine of one adult male ocelot. Despite the differences in size, all specimens appeared morphologically identical and were regarded as A. marcianae. Helminth prevalences and abundances, including those of potentially pathogenic species like D. immitis, were low. Although a single heartworm infection may have contributed to the death of one ocelot, helminth infections in general seemed to be of no great consequence to this endangered ocelot population. The helminth fauna of ocelots in the LRGV is reflective of that from wild felids in general; all have been reported previously from the bobcat (Lynx rufus) and mountain lion (Puma concolor) elsewhere in Texas. PMID:14567231

  4. Why the radiation-attenuated cercarial immunization studies failed to guide the road for an effective schistosomiasis vaccine: A review.

    PubMed

    El Ridi, Rashika; Tallima, Hatem

    2015-05-01

    Schistosomiasis is a debilitating parasitic disease caused by platyhelminthes of the genus Schistosoma, notably Schistosoma mansoni, Schistosoma haematobium, and Schistosoma japonicum. Pioneer researchers used radiation-attenuated (RA) schistosome larvae to immunize laboratory rodent and non-human primate hosts. Significant and reproducible reduction in challenge worm burden varying from 30% to 90% was achieved, providing a sound proof that vaccination against this infection is feasible. Extensive histopathological, tissue mincing and incubation, autoradiographic tracking, parasitological, and immunological studies led to defining conditions and settings for achieving optimal protection and delineating the resistance underlying mechanisms. The present review aims to summarize these findings and draw the lessons that should have guided the development of an effective schistosomiasis vaccine. PMID:26257924

  5. Biochemical and physiological effects of metazoan endoparasites on their host species.

    PubMed

    Thompson, S N

    1983-01-01

    1. The integrative nature of the parasite-host association was discussed, specifically with regard to the metabolic effects of parasitization as well as the physiological manifestation of infection in relation to the host's nutritional physiology. Endocrine interactions were also considered. 2. Relationships involving parasitic insects, including members of the orders Diptera, Hymenoptera and Strepsiptera, parasitic helminths, including members of the phyla Acanthocephala and Nematoda and the classes Cestoidea and Trematoda of the Platyhelminthes, as well as parasitic crustaceans in association with their invertebrate and/or vertebrate, intermediate, paratenic as well as definitive hosts were considered. 3. A broad conceptual or "topic" approach to understanding symbiotic relationships was emphasized. De-emphasis of descriptive categorization and the use of benefit/harm as criteria characterizing parasitic relationships was suggested. 4. The hypothetical concept of host regulation was briefly examined and the use of anthropometric descriptors such as "beneficial" and "harmonious" in parasitology discussed. PMID:6339157

  6. Evolution of the let-7 microRNA Family

    PubMed Central

    Hertel, Jana; Bartschat, Sebastian; Wintsche, Axel; Otto, Christian; of the Bioinformatics Computer Lab, The Students; Stadler, Peter F.

    2012-01-01

    The increase of bodyplan complexity in early bilaterian evolution is correlates with the advent and diversification of microRNAs. These small RNAs guide animal development by regulating temporal transitions in gene expression involved in cell fate choices and transitions between pluripotency and differentiation. One of the two known microRNAs whose origins date back before the bilaterian ancestor is mir-100. In Bilateria, it appears stably associated in polycistronic transcripts with let-7 and mir-125, two key regulators of development. In vertebrates, these three microRNA families have expanded to form a complex system of developmental regulators. In this contribution, we disentangle the evolutionary history of the let-7 locus, which was restructured independently in nematodes, platyhelminths, and deuterostomes. The foundation of a second let-7 locus in the common ancestor of vertebrates and urochordates predates the vertebrate-specific genome duplications, which then caused a rapid expansion of the let-7 family. PMID:22617875

  7. Multigene analysis of lophophorate and chaetognath phylogenetic relationships.

    PubMed

    Helmkampf, Martin; Bruchhaus, Iris; Hausdorf, Bernhard

    2008-01-01

    Maximum likelihood and Bayesian inference analyses of seven concatenated fragments of nuclear-encoded housekeeping genes indicate that Lophotrochozoa is monophyletic, i.e., the lophophorate groups Bryozoa, Brachiopoda and Phoronida are more closely related to molluscs and annelids than to Deuterostomia or Ecdysozoa. Lophophorates themselves, however, form a polyphyletic assemblage. The hypotheses that they are monophyletic and more closely allied to Deuterostomia than to Protostomia can be ruled out with both the approximately unbiased test and the expected likelihood weights test. The existence of Phoronozoa, a putative clade including Brachiopoda and Phoronida, has also been rejected. According to our analyses, phoronids instead share a more recent common ancestor with bryozoans than with brachiopods. Platyhelminthes is the sister group of Lophotrochozoa. Together these two constitute Spiralia. Although Chaetognatha appears as the sister group of Priapulida within Ecdysozoa in our analyses, alternative hypothesis concerning chaetognath relationships could not be rejected. PMID:17937996

  8. Animal biodiversity: An outline of higher-level classification and survey of taxonomic richness (Addenda 2013).

    PubMed

    Zhang, Zhi-Qiang

    2013-01-01

    The kingdom Animalia is here estimated to have a total of 1,659,420 described species (including 133,692 fossil species) in 40 phyla. Among these, the most successful phylum Arthropoda alone represents 1,302,809 species, or about 78.5% of the total. The second largest phylum, Mollusca (118,061 species), is <10% of Arthropoda in diversity, but it is still much more diverse than other successful invertebrate phyla Platyhelminthes (29,488 species), Nematoda (25,043 species), Echinodermata (20,550 species), Annelida (17,426 species), Cnidaria (16,363 species), Bryozoa (11,474 species) and Porifera (10,876 species). The phylum Craniata, including the vertebrates, represents 85,432 species (including 19,974 fossil species): among these, 35,644 species of "fishes", 7,171 species of amphibians, 15,507 species of reptiles, 11,087 species of birds, and 16,014 species of mammals. PMID:26146682

  9. Platyzoan mitochondrial genomes.

    PubMed

    Wey-Fabrizius, Alexandra R; Podsiadlowski, Lars; Herlyn, Holger; Hankeln, Thomas

    2013-11-01

    Platyzoa is a putative lophotrochozoan (spiralian) subtaxon within the protostome clade of Metazoa, comprising a range of biologically diverse, mostly small worm-shaped animals. The monophyly of Platyzoa, the relationships between the putative subgroups Platyhelminthes, Gastrotricha and Gnathifera (the latter comprising at least Gnathostomulida, "Rotifera" and Acanthocephala) as well as some aspects of the internal phylogenies of these subgroups are highly debated. Here we review how complete mitochondrial (mt) genome data contribute to these debates. We highlight special features of the mt genomes and discuss problems in mtDNA phylogenies of the clade. Mitochondrial genome data seem to be insufficient to resolve the position of the platyzoan clade within the Spiralia but can help to address internal phylogenetic questions. The present review includes a tabular survey of all published platyzoan mt genomes. PMID:23274056

  10. Analysis of 18S rRNA gene sequences suggests significant molecular differences between Macrodasyida and Chaetonotida (Gastrotricha).

    PubMed

    Manylov, Oleg G; Vladychenskaya, Natalia S; Milyutina, Irina A; Kedrova, Olga S; Korokhov, Nikolai P; Dvoryanchikov, Gennady A; Aleshin, Vladimir V; Petrov, Nikolai B

    2004-03-01

    Partial 18S rRNA gene sequences of four macrodasyid and one chaetonotid gastrotrichs were obtained and compared with the available sequences of other gastrotrich species and representatives of various metazoan phyla. Contrary to the earlier molecular data, the gastrotrich sequences did not comprise a monophyletic group but formed two distinct clades, corresponding to the Macrodasyida and Chaetonotida, with the basal position occupied by the sequences of Tetranchyroderma sp. and Xenotrichula sp., respectively. Depending on the taxon sampling and methods of analysis, the two clades were separated by various combinations of clades Rotifera, Gnathostomulida, and Platyhelminthes, and never formed a clade with Nematoda. Thus, monophyly of the Gastrotricha is not confirmed by analysis of the presently available molecular data. PMID:15012964