Molecular and morphometric characterization of Thelohanellus caudatus (Myxosporea: Myxobolidae) infecting the caudal fin of Labeo rohita (Hamilton)
Mondal Anjan, Banerjee Sayani, Patra Avijit, Adikesavalu Harresh, Ramudu K. Raghu, Dash Gadadhar, Joardar S.N., Abraham T. Jawahar
Thelohanellus caudatus infecting the caudal fin of carp Labeo rohita was characterized morphologically and by 18S rRNA gene sequence analysis. Infection of Myxobolus spp. and Thelohanelus spp. was more common in L. rohita gills with the parasitic frequency index of 66.67% and 50.00%, respectively. The prevalence of fin infecting Thelohanellus was 12.50%. The infection rate was low to moderate. The plasmodia on the caudal fin were small, white to pale yellow, elongated and 0.5-0.7 mm in length. The caudal fin of infected fish had up to 3 plasmodia, which contained about 50-60 spores each. Morphologically, Thelohanellus species closely resembled Thelohanellus caudatus . The comparison of 18S rRNA gene sequences of T. caudatus to other Thelohanellus spp. available in GenBank revealed only 72-78% homology. The T. caudatus (accession number KC865607) was clustered phylogenetically with the clade of freshwater myxosporeans. In the phylogenetic tree, T. caudatus formed dichotomy with T. hovorkai with low node support. This communication is the first report on molecular characterization of T. caudatus .
Nivicolous myxomycetes in agar culture: some results and open problems
Shchepin Oleg, Novozhilov Yuri, Schnittler Martin
A method to cultivate nivicolous species of myxomycetes in agar is proposed. Sixty three specimens of nivicolous myxomycetes representing 10 taxa (9 species and 1 variety) from 5 genera and 3 families were tested for ability to germinate in agar plates at room temperature. Germination occurred in 28 specimens of 6 species. In some samples microplasmodia started to appear at the same conditions, but in most samples further developmental stages were observed only when cultures were kept at +2°C. Two species ( Lepidoderma chailletii and Physarum nivale ) showed plasmodia formation, but we did not manage to cause sporulation. Partial sequences of the SSU gene obtained from cultured amoebae of two L. chailletii and one P. nivale specimens were identical to those obtained from their spores and comparison with GenBank sequences proved species identity. Some data about tolerance of L. chailletii amoebae to low temperatures were obtained that could be helpful in understanding the ecology of nivicolous myxomycetes.
Morphological description of four new species of Nyctotherus (Ciliophora: Nyctotheridae: Heterotrichida), commensal ciliates of the digestive tract of a terrestrial Oligochaete (Megascolecidae) from the northwest region of Cameroon
Fokam Zéphyrin, Nana Paul Alain, Ngassam Pierre, Bricheux Geneviève, Bouchard Philippe, Vigues Bernard, Sime-Ngando Télesphore
The morphology and ciliature of four Nyctotherus species ( Nyctotherus orthostomatus n. sp., Nyctotherus ndoumeleleensis n. sp., Nyctotherus ngassami n. sp. and Nyctotherus atunibaensis n. sp.), isolated from the mid and hindgut of a Megascolecidae annelid of the genus Eupolytoreutus from the northwest region of Cameroon, were investigated using living observation (methylene blue) and silver impregnation methods (Fernandez-Galiano, 1994). Nyctotherus orthostomatus n. sp. is recognized by a pear-shaped body (128-152 × 95-104 µm); a conspicuous buccal apparatus with the peristome and the infundibulum perpendicular to each other; about 41-46 somatic kineties covering each side of the cell; one transversally elongated massive macronucleus located in the anterior third of the cell, surmounted by a very small spherical micronucleus. Nyctotherus ndoumeleleensis n. sp. is distinguished by the combination of the following characters: ovoid body (151-163 × 87-92 µm) with rounded poles; about 52-68 somatic kineties uniformly covering the cell body; an anterior, transversal and trapezoidal macronucleus carrying laterally a small micronucleus (2-3.5 µm in diameter). Nyctotherus ngassami n. sp. can be distinguished from its congeners by the following set of features: size about 153-269 × 102-148 µm; body ovoid, with 64-86 ciliary rows covering its surface; a small and globular micronucleus hidden by a transversal macronucleus located slightly above the equatorial part of the cell. Nyctotherus atunibaensis n. sp. is characterized by size about 145-253 × 95-162 µm, ovoid cell body, 108-122 somatic kineties, a transversal and arc-shaped macronucleus hiding a small micronucleus. In the present study, new locality (northwest region of Cameroon) and new species of the genus Nyctotherus are explored.
Collection of the proteus-type amoebae at the Institute of Cytology, Russian Academy of Sciences. I. History, goals and research fields
Goodkov Andrew, Yudin Alexander, Podlipaeva Yuliya
Amoebae Culture Collection at the Institute of Cytology RAS in St. Petersburg (Russia) - ACCIC (SPb) - was founded in 1960; it includes strains (clones) of large free living freshwater amoebae of Amoeba proteus -type (family Amoebidae). These protists have been extensively used as model organisms in cell biology for almost two centuries. The amoebae strains were originally received from a number of laboratories and collections of cell cultures in many countries; some strains were raised from the samples isolated directly from nature in various regions of the world. Many of the strains in the ACCIC have been thoroughly characterized. In this paper, history of the Collection and its application in different scientific research fields are briefly presented.