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rDNA Gene (rdna + gene)
Terms modified by rDNA Gene Selected AbstractsRapid identification of B biotype of Bemisia tabaci (Homoptera: Aleyrodidae) based on analysis of internally transcribed spacer 1 sequenceINSECT SCIENCE, Issue 6 2005ZHENG-XI LI Abstract B biotype is a reasonably important biotype among all known biotypes in the Bemisia tabaci species complex. Local populations of B. tabaci on different host plants were collected from across the Chinese mainland, Taiwan, Pakistan and Israel. From each population of B. tabaci, an internally transcribed spacer region of the ribosomal rDNA gene was amplified, cloned and the sequence determined. Sequence homology analyses were performed and the results were similar to those based on morphology and biological characters. Based on analysis of the internally transcribed spacer 1 sequences, a B biotype-specific primer was designed. The PCR diagnosis results showed that B biotype is identifiable by a specific PCR product by using the forward diagnostic primer paired with a universal reverse primer. This diagnostic primer-based protocol can be used for preliminary analysis of mixed Bemisia populations containing B biotype, as well as other biotypes. [source] New model for the formation and function of sagittocysts: Symsagittifera corsicae n. sp. (Acoela)INVERTEBRATE BIOLOGY, Issue 2 2002Robert Gschwentner Abstract. This study is focused on the formation and function of sagittocysts, which are secretions typical of members of the acoel family Sagittiferidae. The needle-shaped sagittocysts are produced in specialized gland cells (sagittocytes) whose distal necks are often surrounded by muscle mantles. Contraction of the muscle mantle ejects the sagittocyst. We establish a model for the development of sagittocytes and muscle mantles out of the stem cell pool of the new acoel species Symsagittifera corsicae. We used various techniques, especially interference and phase-contrast microscopy of living specimens as well as labeling of the body-wall musculature, for species characterization. In addition to the morphological features, we provide the third complete sequence of the 18S rDNA gene in the family Sagittiferidae. [source] Bacterial population dynamics and community structure in a pharmaceutical manufacturing water supply system determined by real-time PCR and PCR-denaturing gradient gel electrophoresisJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2004M. Kawai Abstract Aims:, To control bacteria in the pharmaceutical water supply system. Methods and Results:, Bacteria were enumerated by conventional culture method and fluorescent vital staining. Activated carbon treatment and storage in a tank provided favourable environments for bacterial growth. The bacterial population of the water in both the post-activated carbon treatment and the tank was analysed by denaturing gradient gel electrophoresis (DGGE) with PCR-amplified 16S rDNA fragments including V6, -7, and -8 regions. The bacterial community structure in activated carbon treated water was stable throughout the year. Several kinds of bacteria such as genus Aquaspirillum and Methylobacterium were found in the water after activated carbon treatment. The bacterial community structure was changed and other bacteria such as mycobacteria were detected after storage. Mycobacteria were quantified in water samples using real-time PCR targeting the 16S rDNA gene. Mycobacteria were also detected in tap water and their number was increased 103,104 -fold higher after storage. Conclusion:, These data suggest the importance of culture-independent methods for quality control of water used in pharmaceutical manufacturing. Significance and Impact of the Study:, Critical steps and specified bacteria that should be controlled in the water supply system were recognized by culture-independent methods. These data will enable effective control of water used in the pharmaceutical industry. [source] The life cycle of Henneguya nuesslini Schuberg & Schröder, 1905 (Myxozoa) involves a triactinomyxon-type actinosporeJOURNAL OF FISH DISEASES, Issue 2 2005D M Kallert Abstract The life cycle of the histozoic myxozoan parasite Henneguya nuesslini was investigated in two salmonid host species. Naïve brown trout, Salmo trutta, and brook trout, Salvelinus fontinalis, were experimentally infected in two trials by triactinomyxon type actinospores from naturally infected Tubifex tubifex. In exposed common carp, Cyprinus carpio, no myxospore production was detected. The parasite formed cysts with mature myxospores in the connective tissue of the fish 102 days post-exposure. The morphology of both actinosporean and myxosporean stages was described by light microscopy and a 1417-bp fragment of the 18S rDNA gene was sequenced. Sequence analysis confirmed the absolute congruence of the two developmental stages and assisted in determining species identity. Host range, tissue specificity and myxospore measurements provided sufficiently distinctive features to confirm species validity and were thus crucial for identification. The triactinomyxon spores had 16 secondary germ cells, unique dimensions, a very opaque sporoplasm matrix and three conspicuously protruding, pyriform polar capsules. This is the first record of a Henneguya sp. life cycle with a triactinomyxon-type actinospore, which suggests a close relationship with the Myxobolus group and a polyphyletic origin of the genus Henneguya. [source] PHYLOGENY OF THE EUGLENOPHYTES INFERRED FROM SSU AND LSU rDNAJOURNAL OF PHYCOLOGY, Issue 2001Article first published online: 24 SEP 200 Zimmermann, S. & Triemer, R. E. Department of Life Sciences, Rutgers University, Piscataway, NJ 08854 USA The phylogeny of the Euglenophytes has previously been examined using the SSU rDNA. Results from these analyses indicated that the phototrophic genera are not monophyletic. To test this hypothesis, a second gene was sequenced, the LSU rDNA. The taxa used in this study were selected from clades represented in the SSU analyses so that comparisons could be made between gene phylogenies and a combined dataset could be created. Conserved areas of the aligned sequences for both the LSU and SSU were used to generate parsimony, maximum likelihood, and distance trees. Topology of the SSU and LSU trees was similar. The SSU and LSU data consistently generated the same four highly supported terminal clades and varied only in the placement of Euglena stellata and Euglena viridis. The internal nodes of the SSU trees were weakly supported, whereas the LSU provided higher support for these nodes. A combined LSU and SSU dataset was then created. Analysis of the combined dataset yielded trees with identical topologies to those found in the individual datasets and demonstrated strong support for the four terminal clades. These results show that phylogeny of the Euglenophytes as inferred previously from SSU data is confirmed by the LSU data and that the LSU rDNA gene may be useful in elucidating relationships among the major clades. [source] SOME PHYLOGENETIC RELATIONSHIPS WITHIN THE OSCILLATORIALES (CYANOBACTERIA) CLADE USING 16S RDNA GENE SEQUENCE DATAJOURNAL OF PHYCOLOGY, Issue 2000D.A. Casamatta An approximately 1400 base pair region of the 16S rDNA gene was sequenced from taxa within the Oscillatoriales in order to assess phylogenetic relationships. Ten previously unsequenced strains were obtained from the University of Toronto Culture Collection. New sequence data were combined with previously published sequences from a wide representation of cyanobacteria including all currently available, complete Oscillatorialian taxa. Trees constructed using parsimony, distance, and maximum likelihood methods were similar in topology, although a few taxa were variable in their placement depending on the phylogenetic method employed. Newly sequenced taxa of the genera Phormidium, Oscillatoria, and Lyngbya did not form monophyletic clades based on traditional generic designations. Two Lyngbya strains (UTCC296 and 313) and Phormidium subfuscum (UTCC474) formed a well supported monophyletic clade, but the affinity of this clade with other groups was uncertain due to lack of bootstrap support. Oscillatoria sp. (UTCC393) was closely related to the previously sequenced Oscillatoria limnetica and likewise, Phormidium molle (UTCC77) and Phormidium tenue (UTCC473) were placed in a well supported clade with other Oscillatoriales. The other four taxa were variously placed in the trees and their phylogenetic positions could not be determined with certainty. [source] Molecular Characterization and Potential Insect Vector of a Phytoplasma Associated with Garden Beet Witches' Broom in Yazd, IranJOURNAL OF PHYTOPATHOLOGY, Issue 4 2007A. Mirzaie Abstract In 2002, garden beet witches' broom (GBWB) phytoplasma was detected for the first time in garden beet plants (Beta vulgaris L. ssp. esculenta) in Yazd, Iran. Nested polymerase chain reaction (PCR) and restriction fragment length polymorphic (RFLP) analysis of PCR-amplified phytoplasma 16S rDNA were employed for the detection and identification of the phytoplasma associated with garden beet. A phytoplasma belonging to subgroup 16SrII-E, in the peanut witches' broom group (16SrII), was detected in infected plants. Asymptomatic plant samples and the negative control yielded no amplification. The result of analysis of the nucleotide sequence of a 1428 bp fragment of 16S rDNA gene from GBWB phytoplasma (GenBank accession number DQ302722) was basically consistent with the classification based on RFLP analysis, in which GBWB phytoplasma clustered with phytoplasmas of the 16SrII-E subgroup. A search for a natural phytoplasma vector was conducted in Yazd in 2004, in an area where garden beet crops had been affected since 2002. The associated phytoplasma was detected in one leafhopper species, Orosius albicinctus, commonly present in this region. The leafhopper O. albicinctus was used in transmission tests to determine its vector status for the phytoplasma associated with GBWB. Two of eight plants that had been fed on by O. albicinctus, showed mild symptoms of GBWB including stunting and reddening of midveins. A phytoplasma was detected in the two symptomatic test plants by PCR using universal primers and it was identified by RFLP as the GBWB phytoplasma. This finding suggests O. albicinctus is a vector of the GBWB phytoplasma. [source] Identification of Microsporum canis from dermatophytic pseudomycetoma in paraffin-embedded veterinary specimens using a common PCR protocolMYCOSES, Issue 3 2007Simona Nardoni Summary The effectiveness of a simple PCR protocol performed on paraffin-embedded tissues, obtained from histopathologically and culturally diagnosed cases of dermatophytic pseudomycetoma DPM was tested. The specimens were investigated using previously described primers (DH1L and DH1R) targeting the 18S rDNA gene and amplifying a 183-bp fragment. Microsporum canis was identified from all samples. The PCR protocol described in the present work demonstrated a 100% concordant result comparing the molecular characterisation with phenotypic characterisation of dermatophytes. Molecular biology could represent a valid identification tool in dermatophytic deep infections, when diagnosis cannot be achieved by cultural methods. [source] Genotype distribution of Candida albicans isolates by 25S intron analysis with regard to invasivenessMYCOSES, Issue 11-12 2004Z. C. Karahan Candida albicans; Genotyp; Invasivität Summary The aim of this study was to genotype Candida albicans strains isolated from patients with invasive and non-invasive deep-seated infections. For this purpose, 301 C. albicans isolates (81 invasive and 220 non-invasive) were genotyped by using specific PCR primers designed to span the transposable group I intron of the 25S rDNA gene. Fifty-three of the 81 invasive isolates were genotype A (65.4%), eight were genotype B (9.9%) and 20 were genotype C (24.7%), while 98 of the 220 non-invasive isolates were genotype A (44.6%), 46 were genotype B (20.9%) and 76 were genotype C (34.5%). Genotype A was more prevalent among invasive isolates and genotypes B and C were more prevalent among non-invasive isolates (P = 0.0046). Genotypes D and E which represent C. dubliniensis were not found. These results indicate that there may be a relationship between C. albicans genotypes and invasiveness; genotype A being more invasive than others. The presence or absence of the transposable group I intron in the 25S rDNA gene may be important in determining the invasiveness of C. albicans. Zusammenfassung Ziel dieser Arbeit war, Candida albicans -Isolate von Patienten mit invasiven und nicht-invasiven Läsionen zu genotypisieren. Es wurden 301 Isolate (81 invasive und 220 nicht-invasive) untersucht. Die Genotypisierung wurde mittels eines spezifischen PCR Primers, der das Group I-Intron des 25S rDNA Gens umfasst, durchgeführt. 53 der invasiven Isolate waren Genotyp A (65,4%), 8 Genotyp B (9,9%), und 20 Genotyp C (24,7%); anderseits waren 98 der nicht-invasiven Isolate Genotyp A (44,6%), 46 Genotyp B (20,9%), und 76 Genotyp C (34,5%). Genotyp A überwog unter invasiven Isolaten, während die Genotypen B und C unter nicht-invasiven Isolaten vorherrschten (P = 0.0046). Die Genotypen D und E, die Candida dubliniensis umfassen, wurden nicht gefunden. Diese Ergebnisse zeigen, dass es eine Beziehung zwischen C. albicans -Genotypen und Invasivität gibt und dass Genotyp A invasiver ist als andere. Das Group I-Intron des 25S rDNA Gens scheint für die Invasivitätsabschätzung bei C. albicans brauchbar zu sein. [source] Ultrastructure and large subunit rDNA sequences of Lepidodinium viride reveal a close relationship to Lepidodinium chlorophorum comb. nov. (=Gymnodinium chlorophorum)PHYCOLOGICAL RESEARCH, Issue 1 2007Gert Hansen SUMMARY The ultrastructure of the green dinoflagellate Lepididodinium viride M. M. Watanabe, S. Suda, I. Inouye Sawaguchi et Chihara was studied in detail. The nuclear envelope possessed numerous chambers each furnished with a nuclear pore, a similar arrangement to that found in other gymnodinioids. The flagellar apparatus was essentially identical to Gymnodinium chlorophorum Elbrächter et Schnepf, a species also containing chloroplasts of chlorophyte origin. Of particular interest was the connection of the flagellar apparatus to the nuclear envelope by means of both a fiber and a microtubular extension of the R3 flagellar root. This feature has not been found in other dinoflagellates and suggests a close relationship between these two species. This was confirmed by phylogenetic analysis based on partial sequences of the large subunit (LSU) rDNA gene of L. viride, G. chlorophorum and 16 other unarmoured dinoflagellates, including both the ,type' culture and a new Tasmanian isolate of G. chlorophorum. These two isolates had identical sequences and differed from L. viride by only 3.75% of their partial LSU sequences, considerably less than the difference between other Gymnodinium species. Therefore, based on ultrastructure, pigments and partial LSU rDNA sequences, the genus Lepidodinium was emended to encompass L. chlorophorum comb. nov. [source] Development of species-specific primers for the ectoparasitic nematode species Xiphinema brevicolle, X. diffusum, X. elongatum, X. ifacolum and X. longicaudatum (Nematoda: Longidoridae) based on ribosomal DNA sequencesANNALS OF APPLIED BIOLOGY, Issue 3 2005CLAUDIO M G OLIVEIRA Summary The objective of this study was to develop single-step PCR species-specific primers that reliably discriminate four economically important Xiphinema species (X. brevicolle, X. elongatum, X. ifacolum and X. longicaudatum) and X. diffusum that is taxonomically very similar to X. brevicolle. Each species-specific reverse primer was located in the ITS-1 rDNA region and was used in combination with a universal forward primer located in the 18S rDNA gene. Primer reliability was confirmed by screening seven and 11 populations, respectively of X. diffusum and X. elongatum. Potential species-specific primers were also identified for X. brevicolle, X. longicaudatum and X. ifacolum, however too few populations of these species were available to thoroughly assess their reliability. For all species-specific primers, specificity was demonstrated by the absence of cross-reactions with 14 non-target Xiphinema species. Multiplex PCR was effective and reproducible for two (X. longicaudatum and X. ifacolum) or three (X. brevicolle, X. diffusum and X. elongatum) of the target nematode species, thus improving the applicability of the diagnostic primers. [source] A land snail's view of a fragmented landscapeBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2009HEIKE KAPPES Habitat fragmentation may influence the genetic structure of populations, especially of species with low mobility. So far, these effects have been mainly studied by surveying neutral markers, and much less by looking at ecologically relevant characters. Therefore, we aimed to explore eventual patterns of covariation between population structuring in neutral markers and variation in shell morphometrics in the forest-associated snail Discus rotundatus in relation to habitat fragment characteristics. To this end, we screened shell morphometric variability and sequence variation in a fragment of the mitochondrial 16S rDNA gene in D. rotundatus from the fragmented landscape of the Lower Rhine Embayment, Germany. The 16S rDNA of D. rotundatus was highly variable, with a total of 118 haplotypes (384 individuals) forming four clades and one unresolved group. There was a geographic pattern in the distribution of the clades with the river Rhine apparently separating two groups. Yet, at the geographic scale considered, there was no obvious effect of fragmentation on shell morphometrics and 16S rDNA variation because GST often was as high within, as between forests. Instead, the age of the habitat and (re-)afforestation events appeared to affect shell shape and 16S rDNA in terms of the number of clades per site. The ecologically relevant characters thus supported the presumably neutral mitochondrial DNA markers by indicating that populations of not strictly stenecious species may be (relatively) stable in fragments. However, afforestation after large clearcuts and habitat gain after the amendment of deforestation are accompanied by several, seemingly persistent peculiarities, such as altered genetic composition and shell characters (e.g. aperture size). © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 839,850. [source] Sulfate-reducing bacteria in marine sediment (Aarhus Bay, Denmark): abundance and diversity related to geochemical zonationENVIRONMENTAL MICROBIOLOGY, Issue 5 2009Julie Leloup Summary In order to better understand the main factors that influence the distribution of sulfate-reducing bacteria (SRB), their population size and their metabolic activity in high- and low-sulfate zones, we studied the SRB diversity in 3- to 5-m-deep sediment cores, which comprised the entire sulfate reduction zone and the upper methanogenic zone. By combining EMA (ethidium monoazide that can only enter damaged/dead cells and may also bind to free DNA) treatment with real-time PCR, we determined the distributions of total intact bacteria (16S rDNA genes) and intact SRB (dsrAB gene), their relative population sizes, and the proportion of dead cells or free DNA with depth. The abundance of SRB corresponded in average to 13% of the total bacterial community in the sulfate zone, 22% in the sulfate,methane transition zone and 8% in the methane zone. Compared with the total bacterial community, there were relatively less dead/damaged cells and free DNA present than among the SRB and this fraction did not change systematically with depth. By DGGE analysis, based on the amplification of the dsrA gene (400 bp), we found that the richness of SRB did not change with depth through the geochemical zones; but the clustering was related to the chemical zonation. A full-length clone library of the dsrAB gene (1900 bp) was constructed from four different depths (20, 110, 280 and 500 cm), and showed that the dsrAB genes in the near-surface sediment (20 cm) was mainly composed of sequences close to the Desulfobacteraceae, including marine complete and incomplete oxidizers such as Desulfosarcina, Desulfobacterium and Desulfococcus. The three other libraries were predominantly composed of Gram-positive SRB. [source] Intrapopulational polymorphism of nucleolus organizer regions in Serrapinnus notomelas (Characidae, Cheirodontinae) from the Paraná RiverJOURNAL OF FISH BIOLOGY, Issue 5 2008A. P. Santi-Rampazzo Analysis of the nucleolus organizer regions by silver nitrate (AgNOR), fluorescent in situ hybridization (FISH) and C-banding of Serrapinnus notomelas from the Paraná River, PR, Brazil revealed intrapopulational polymorphisms that could be classified into six patterns (I,VI). Pattern I consisted of a single nucleolus organizer region (NOR) on chromosome pair 26 with at least one active homologue, indicating that it was a preferential NO. This NOR was also present in all the other patterns. In addition, seven other variable pairs appeared in patterns II,VI. These polymorphisms may indicate transpositions of rDNA genes, located on pair 26, to various sites in the genome. These transpositions may be due to transpose mechanisms or reinsertion into sites that have sequences homologous with the inserts. C-band analysis also reflected this variability and confirmed the various patterns described here. [source] PHYLOGENY OF THE EUGLENALES INFERRED FROM PLASTID LSU rDNA SEQUENCES,JOURNAL OF PHYCOLOGY, Issue 4 2008Jong Im Kim To gain insights into the phylogeny of the Euglenales, we analyzed the plastid LSU rDNA sequences from 101 strains of the photosynthetic euglenoids belonging to nine ingroup genera (Euglena, Trachelomonas, Strombomonas, Monomorphina, Cryptoglena, Colacium, Discoplastis, Phacus, and Lepocinclis) and two outgroup genera (Eutreptia and Eutreptiella). Bayesian and maximum-likelihood (ML) analyses resulted in trees of similar topologies and four major clades: a Phacus and Lepocinclis clade; a Colacium clade; a Trachelomonas, Strombomonas, Monomorphina, and Cryptoglena clade; and a Euglena clade. The Phacus and Lepocinclis clade was the sister group of all other euglenalian genera, followed by Discoplastis spathirhyncha (Skuja) Triemer and the Colacium clade, respectively, which was inconsistent with their placement based on nuclear rDNA genes. The Trachelomonas, Strombomonas, Monomorphina, and Cryptoglena clade was sister to the Euglena clade. The loricate genera, Trachelomonas and Strombomonas, were closely related to each other, while Monomorphina and Cryptoglena also grouped together. The Euglena clade formed a monophyletic lineage comprising most species from taxa formerly allocated to the subgenera Calliglena and Euglena. However, within this genus, none of the subgenera was monophyletic. [source] Detection of Phytophthora nicotianae in Soil with Real-time Quantitative PCRJOURNAL OF PHYTOPATHOLOGY, Issue 1 2010Junli Huang Abstract Phytophthora nicotianae is one of the most important soil-borne plant pathogens. A rapid, specific and sensitive real-time polymerase chain reaction (PCR) detection method for P. nicotianae was established, which used primers targeting the internal transcribed spacer (ITS) regions of rDNA genes of Phytophthora spp. Based on the nucleotide sequences of ITS2 of 15 different species of Phytophthora, the primers and probe were designed specifically to amplify DNA from P. nicotianae. With a series of 10-fold DNA dilutions extracted from P. nicotianae pure cultures, the detection limit was 10 pg/,l in conventional PCR, whereas in SYBR Green I PCR the detection limit was 0.12 fg/,l and in TaqMan PCR 1.2 fg/,l, and real-time PCR was 104,105 times more sensitive than conventional PCR. The simple and rapid procedures maximized the yield and quality of recovered DNA from soil and allowed the processing of many samples in a short time. The direct DNA extractions from soil were utilized to yield DNA suitable for PCR. By combining this protocol with the real-time PCR procedure it has been possible to specifically detect P. nicotianae in soil, and the degree of sensitivity was 1.0 pg/,l. The system was applied to survey soil samples from tobacco field sites in China for the presence of P. nicotianae and the analyses of naturally infested soil showed the reliability of the real-time PCR method. [source] Measuring rDNA diversity in eukaryotic microbial systems: how intragenomic variation, pseudogenes, and PCR artifacts confound biodiversity estimatesMOLECULAR ECOLOGY, Issue 24 2007DANIEL J. THORNHILL Abstract Molecular approaches have revolutionized our ability to study the ecology and evolution of micro-organisms. Among the most widely used genetic markers for these studies are genes and spacers of the rDNA operon. However, the presence of intragenomic rDNA variation, especially among eukaryotes, can potentially confound estimates of microbial diversity. To test this hypothesis, bacterially cloned PCR products of the internal transcribed spacer (ITS) region from clonal isolates of Symbiodinium, a large genus of dinoflagellates that live in symbiosis with many marine protists and invertebrate metazoa, were sequenced and analysed. We found widely differing levels of intragenomic sequence variation and divergence in representatives of Symbiodinium clades A to E, with only a small number of variants attributed to Taq polymerase/bacterial cloning error or PCR chimeras. Analyses of 5.8S-rDNA and ITS2 secondary structure revealed that some variants possessed base substitutions and/or indels that destabilized the folded form of these molecules; given the vital nature of secondary structure to the function of these molecules, these likely represent pseudogenes. When similar controls were applied to bacterially cloned ITS sequences from a recent survey of Symbiodinium diversity in Hawaiian Porites spp., most variants (~87.5%) possessed unstable secondary structures, had unprecedented mutations, and/or were PCR chimeras. Thus, data obtained from sequencing of bacterially cloned rDNA genes can substantially exaggerate the level of eukaryotic microbial diversity inferred from natural samples if appropriate controls are not applied. These considerations must be taken into account when interpreting sequence data generated by bacterial cloning of multicopy genes such as rDNA. [source] Taxonomic Redescriptions of Two Ciliates, Protogastrostyla pulchra n. g., n. comb. and Hemigastrostyla enigmatica (Ciliophora: Spirotrichea, Stichotrichia), with Phylogenetic Analyses Based on 18S and 28S rRNA Gene SequencesTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 6 2007JUN GONG ABSTRACT. The morphology and infraciliature of two stichotrichid ciliates, Gastrostyla pulchra(Perejaslawzewa 1886) Kahl, 1932 and Hemigastrostyla enigmatica(Dragesco and Dragesco-Kernéis 1986) Song & Wilbert, 1997, collected from marine and brackish sediments, were investigated by using living observations and protargol impregnations. Both 18S and 28S rRNA genes of these two species were sequenced. The 18S rDNA show high similarities (98.4%,99.7%) among populations of each species. There is about 94% similarity in 18S rDNA genes between G. pulchra and Gastrostyla steinii, the type species of the genus, which has been confirmed to be an oxytrichid by previous studies. In the phylogenetic trees of 18S, 28S, and combined 18S and 28S rDNA, both G. pulchra and H. enigmatica are consistently placed outside the well-established oxytrichid clade. Based on our analyses and previous ontogenetic data, we conclude that these two species may represent some lower groups in the subclass Stichotrichia, and that G. pulchra should represent a new genus, Protogastrostyla n. g. This new genus, which is morphologically similar to Gastrostyla, differs in its morphogenesis: the apical part of the old AZM is retained combining with the newly built membranelles that develop from the proter's oral primordium; the primary primordia of the dorsal kinety; and marginal primordia commence de novo without a definite contribution from the old structure. [source] Detection of the Dinozoans Pfiesteria piscicida and P. shumwayae: A Review of Detection Methods and Geographic Distribution,THE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 2 2005PARKE A. RUBLEE Abstract. Molecular methods, including conventional PCR, real-time PCR, denaturing gradient gel electrophoresis, fluorescent fragment detection PCR, and fluorescent in situ hybridization, have all been developed for use in identifying and studying the distribution of the toxic dinoflagellates Pfiesteria piscicida and P. shumwayae. Application of the methods has demonstrated a worldwide distribution of both species and provided insight into their environmental tolerance range and temporal changes in distribution. Genetic variability among geographic locations generally appears low in rDNA genes, and detection of the organisms in ballast water is consistent with rapid dispersal or high gene flow among populations, but additional sequence data are needed to verify this hypothesis. The rapid development and application of these tools serves as a model for study of other microbial taxa and provides a basis for future development of tools that can simultaneously detect multiple targets. 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