scholarly journals Low internal transcribed spacer rDNA variation in New Zealand Bonamia ostreae: evidence for a recent arrival

2020 ◽  
Vol 139 ◽  
pp. 121-130 ◽  
Author(s):  
HS Lane ◽  
JB Jones
Keyword(s):  
New Zealand ◽  
Northern Hemisphere ◽  
Internal Transcribed Spacer ◽  
18S Rrna Gene ◽  
Its Rdna ◽  
Rrna Gene ◽  
Rdna Sequences ◽  
Rdna Variation ◽  
Bonamia Ostreae ◽  
High Level

Bonamia ostreae is a haplosporidian parasite of oysters that was first reported to occur in the Southern Hemisphere in 2015 in the New Zealand flat oyster Ostrea chilensis. Until that report, B. ostreae had been restricted to populations of O. edulis within the Northern Hemisphere. This large range extension raised questions regarding B. ostreae dispersal, including whether B. ostreae is a recent introduction and from where it originated. The whole 18S rRNA gene of New Zealand B. ostreae revealed 99.9-100% sequence homology to other published B. ostreae 18S rDNA sequences. Internal transcribed spacer (ITS) rDNA sequences (n = 29) were generated from New Zealand B. ostreae and compared to published B. ostreae sequences from 3 Northern Hemisphere sites: California, USA (n = 18), Maine, USA (n = 7), and the Netherlands (n = 6) to investigate intraspecific variation. Low ITS rDNA variation was observed from New Zealand B. ostreae isolates, and high levels of variation were observed from Northern Hemisphere B. ostreae sequences. We hypothesise that the low ITS rDNA diversity found in New Zealand B. ostreae is the result of a founder effect resulting from a single introduction from a limited number of propagules. The high level of ITS rDNA variation from the Northern Hemisphere prevented inferences of dispersal origins. New Zealand B. ostreae were genetically differentiated from all sites, and additional genetic data are required to better determine the origin of B. ostreae in New Zealand.

scholarly journals High-Level Congruence of Myrionecta rubra Prey and Dinophysis Species Plastid Identities as Revealed by Genetic Analyses of Isolates from Japanese Coastal Waters

2010 ◽  
Vol 76 (9) ◽  
pp. 2791-2798 ◽  
Author(s):  
Goh Nishitani ◽  
Satoshi Nagai ◽  
Katsuhisa Baba ◽  
Susumu Kiyokawa ◽  
Yuki Kosaka ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Coastal Waters ◽  
Primary Source ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Gene Sequences ◽  
Myrionecta Rubra ◽  
High Level ◽  
Almost All

ABSTRACT We analyzed cryptophyte nucleomorph 18S rRNA gene sequences retained in natural Myrionecta rubra cells and plastid 16S rRNA gene and psbA sequences retained in natural cells of several Dinophysis species collected from Japanese coastal waters. A total of 715 nucleomorph sequences obtained from 134 M. rubra cells and 564 plastid 16S rRNA gene and 355 psbA sequences from 71 Dinophysis cells were determined. Almost all sequences in M. rubra and Dinophysis spp. were identical to those of Teleaulax amphioxeia, suggesting that M. rubra in Japanese coastal waters preferentially ingest T. amphioxeia. The remaining sequences were closely related to those of Geminigera cryophila and Teleaulax acuta. Interestingly, 37 plastid 16S rRNA gene sequences, which were different from T. amphioxeia and amplified from Dinophysis acuminata and Dinophysis norvegica cells, were identical to the sequence of a D. acuminata cell found in the Greenland Sea, suggesting that a widely distributed and unknown cryptophyte species is also preyed upon by M. rubra and subsequently sequestered by Dinophysis. To confirm the reliability of molecular identification of the cryptophyte Teleaulax species detected from M. rubra and Dinophysis cells, the nucleomorph and plastid genes of Teleaulax species isolated from seawaters were also analyzed. Of 19 isolates, 16 and 3 clonal strains were identified as T. amphioxeia and T. acuta, respectively, and no sequence variation was confirmed within species. T. amphioxeia is probably the primary source of prey for M. rubra in Japanese coastal waters. An unknown cryptophyte may serve as an additional source, depending on localities and seasons.

Morphological and molecular characterization of Mermisnigrescens Dujardin, (Nematoda: Mermithidae) parasitizing the introduced European earwig (Dermaptera: Forficulidae) in New Zealand

2014 ◽  
Vol 89 (3) ◽  
pp. 267-276 ◽  
Author(s):  
B. Presswell ◽  
S. Evans ◽  
R. Poulin ◽  
F. Jorge
Keyword(s):  
New Zealand ◽  
18S Rrna ◽  
Sequence Data ◽  
18S Rrna Gene ◽  
Parasitic Nematodes ◽  
Rrna Gene ◽  
28S Rrna ◽  
Forficula Auricularia ◽  
Adult Females ◽  
European Earwig

AbstractParasitic nematodes of the family Mermithidae were found to be infecting the introduced European earwig Forficula auricularia (Dermaptera: Forficulidae) in Dunedin, South Island, New Zealand. Adult females were later collected from various garden plants while depositing eggs. These mermithid specimens were identified morphologically as Mermis nigrescens Dujardin, 1842. A genetic distance of 0.7% between these specimens and a M. nigrescens isolate from Canada (18S rRNA gene), suggests that they have diverged genetically, but there are currently no available comparable sequences for the European M. nigrescens. Two additional nuclear fragments were also amplified, the 28S rRNA and the ribosomal DNA first internal transcribed spacer (ITS1), providing a basis for future studies. Bearing in mind the morphological similarity with other reported M. nigrescens and the lack of sequence data from other parts of the world, we retain the name M.nigrescens, and suggest that the species may be found to represent a complex of cryptic species when more worldwide data are available. Herein, we present a brief description of the post-parasitic worms and adult females, along with an inferred phylogeny using 18S rRNA gene sequences.

Intra-chromosomal heterogeneity between the four 16S rRNA gene copies in the genus Veillonella: implications for phylogeny and taxonomy

Microbiology ◽  
2003 ◽  
Vol 149 (6) ◽  
pp. 1493-1501 ◽  
Author(s):  
Hélène Marchandin ◽  
Corinne Teyssier ◽  
Michèle Siméon de Buochberg ◽  
Hélène Jean-Pierre ◽  
Christian Carriere ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rdna ◽  
Clinical Isolates ◽  
Clinical Strain ◽  
Species Differentiation ◽  
Rrna Gene ◽  
Rdna Sequences ◽  
Gene Copies ◽  
High Level ◽  
Human Flora

Among the seven species characterized within the genus Veillonella, three (Veillonella dispar, Veillonella parvula and Veillonella atypica) have so far been isolated from human flora and during infectious processes. Sequencing and analysis of 16S rDNA (rrs) has been described as the best method for identification of Veillonella strains at the species level since phenotypic characteristics are unable to differentiate between species. rrs sequencing for the three species isolated from humans showed more than 98 % identity between them. Four rrs copies were found in the reference strains and in all the clinical isolates studied. The sequences of each rrs were determined for the clinical strain ADV 360.1, and they showed a relatively high level of heterogeneity (1·43 %). In the majority of cases, polymorphic positions corresponded to nucleotides allowing differentiation between the three species isolated from humans. Moreover, variability observed between rrs copies was higher than that between 16S rDNA sequences of V. parvula and V. dispar. Phylogenetic analysis showed that polymorphism between rrs copies affected the position of strain ADV 360.1 in the tree. Variable positions occurred in stems and loops belonging to variable and hypervariable regions of the 16S rRNA secondary structure but did not change the overall structure of the 16S rRNA. PCR-RFLP experiments performed on 27 clinical isolates of Veillonella sp. suggested that inter-rrs heterogeneity occurs widely among the members of the genus Veillonella. These results, together with the lack of phenotypic criteria for species differentiation, give preliminary arguments for unification of V. dispar and V. parvula.

scholarly journals Preliminary analysis of New Zealand scampi (Metanephrops challengeri) diet using metabarcoding

2018 ◽  
Author(s):  
Aimee L van der Reis ◽  
Olivier Laroche ◽  
Andrew G Jeffs ◽  
Shane D Lavery
Keyword(s):  
New Zealand ◽  
Preliminary Analysis ◽  
18S Rrna ◽  
18S Rrna Gene ◽  
Coi Gene ◽  
Taxonomic Resolution ◽  
Gut Contents ◽  
Rrna Gene ◽  
Diverse Range ◽  
Dna Metabarcoding

Deep sea lobsters are highly valued for seafood and provide the basis of important commercial fisheries in many parts of the world. Despite their economic significance, relatively little is known about their natural diets. Microscopic analyses of foregut content in some species have suffered from low taxonomic resolution, with many of the dietary items difficult to reliably identify as their tissue is easily digested. DNA metabarcoding has the potential to provide greater taxonomic resolution of the diet of the New Zealand scampi (Metanephrops challengeri) through the identification of gut contents, but a number of methodological concerns need to be overcome first to ensure optimum DNA metabarcoding results. In this study, a range of methodological parameters were tested to determine the optimum protocols for DNA metabarcoding, and provide a first view of M. challengeri diet. Several PCR protocols were tested, using two universal primer pairs targeting the 18S rRNA and COI genes, on DNA extracted from both frozen and ethanol preserved samples for both foregut and hindgut digesta. The selection of appropriate DNA polymerases, buffers and methods for reducing PCR inhibitors (including the use of BSA) were found to be critical. Amplification from frozen or ethanol preserved gut contents appeared similarly dependable, but metabarcoding outcomes indicated that the ethanol samples produced better results from the COI gene. The COI gene was found to be more effective than 18S rRNA gene for identifying large eukaryotic taxa from the digesta, however, it was less successfully amplified. The 18S rRNA gene was more easily amplified, but identified mostly smaller marine organisms such as plankton and parasites. This preliminary analysis of the diet of M. challengeri identified a range of species (13,541 reads identified as diet), which included the ghost shark (Hydrolagus novaezealandiae), silver warehou (Seriolella punctate), tall sea pen (Funiculina quadrangularis) and the salp (Ihlea racovitza), suggesting that they have a varied diet, with a high reliance on scavenging a diverse range of pelagic and benthic species from the seafloor.

scholarly journals Free-Living Protozoa in Two Unchlorinated Drinking Water Supplies, Identified by Phylogenic Analysis of 18S rRNA Gene Sequences

2009 ◽  
Vol 75 (14) ◽  
pp. 4736-4746 ◽  
Author(s):  
Rinske M. Valster ◽  
Bart A. Wullings ◽  
Geo Bakker ◽  
Hauke Smidt ◽  
Dick van der Kooij
Keyword(s):  
Drinking Water ◽  
Legionella Pneumophila ◽  
Distribution System ◽  
18S Rrna ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Free Living ◽  
Water Supplies ◽  
Molecular Approaches ◽  
High Level

ABSTRACT Free-living protozoan communities in water supplies may include hosts for Legionella pneumophila and other undesired bacteria, as well as pathogens. This study aimed at identifying free-living protozoa in two unchlorinated groundwater supplies, using cultivation-independent molecular approaches. For this purpose, samples (<20°C) of treated water, distributed water, and distribution system biofilms were collected from supply A, with a low concentration of natural organic matter (NOM) (<0.5 ppm of C), and from supply B, with a high NOM concentration (7.9 ppm of C). Eukaryotic communities were studied using terminal restriction fragment length polymorphism and clone library analyses of partial 18S rRNA gene fragments and a Hartmannella vermiformis-specific quantitative PCR (qPCR). In both supplies, highly diverse eukaryotic communities were observed, including free-living protozoa, fungi, and metazoa. Sequences of protozoa clustered with Amoebozoa (10 operational taxonomic units [OTUs]), Cercozoa (39 OTUs), Choanozoa (26 OTUs), Ciliophora (29 OTUs), Euglenozoa (13 OTUs), Myzozoa (5 OTUs), and Stramenopiles (5 OTUs). A large variety of protozoa were present in both supplies, but the estimated values for protozoan richness did not differ significantly. H. vermiformis was observed in both supplies but was not a predominant protozoan. One OTU with the highest similarity to Acanthamoeba polyphaga, an opportunistic human pathogen and a host for undesired bacteria, was observed in supply A. The high level of NOM in supply B corresponded with an elevated level of active biomass and with elevated concentrations of H. vermiformis in distributed water. Hence, the application of qPCR may be promising in elucidating the relationship between drinking water quality and the presence of specific protozoa.

Evolution and function of B chromosome 45S rDNA sequences in Brachycome dichromosomatica

Genome ◽  
2007 ◽  
Vol 50 (7) ◽  
pp. 638-644 ◽  
Author(s):  
Sylvia Marschner ◽  
Armin Meister ◽  
Frank R. Blattner ◽  
Andreas Houben
Keyword(s):  
Phylogenetic Analysis ◽  
Internal Transcribed Spacer ◽  
B Chromosome ◽  
Its2 Sequence ◽  
B Chromosomes ◽  
Rrna Gene ◽  
45S Rdna ◽  
Internal Transcribed Spacer 2 ◽  
Rdna Sequences ◽  
And Function

The origin and activity of 45S rDNA located on micro B chromosomes of the daisy Brachycome dichromosomatica were analysed. The internal transcribed spacer 2 (ITS2) of the 45S rRNA gene was sequenced for micro B, large B, and A chromosomes of B. dichromosomatica cytodeme A2, and conserved differences were identified between sequences originating from A and both types of B chromosomes. Phylogenetic analysis did not identify a species containing an ITS2 sequence more similar to either of the B chromosome sequences than the B. dichromosomatica A chromosome sequences. Thus, an origin of the B chromosomes from A chromosomes at a time prior to the divergence of the 4 cytodemes of B. dichromosomatica is suggested. The frequent (70%) nucleolar non-association of micro B chromosomes suggests inactivity of micro B 45S rDNA.

Sequence variation in two mitochondrial DNA regions and internal transcribed spacer among isolates of the nematode Oesophagostomum asperum originating from goats in Hunan Province, China

2014 ◽  
Vol 90 (1) ◽  
pp. 1-6 ◽  
Author(s):  
F. Li ◽  
T. Hu ◽  
N.C. Duan ◽  
W.Y. Li ◽  
Q. Teng ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Internal Transcribed Spacer ◽  
Phylogenetic Analyses ◽  
Its Rdna ◽  
Hunan Province ◽  
Nuclear Ribosomal Dna ◽  
Specific Sequence ◽  
5.8S Rdna ◽  
Rdna Sequences ◽  
Specific Variation

AbstractThe present study examined sequence variability in two mitochondrial DNA (mtDNA) regions, namely cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase subunit 1 (nad1), and internal transcribed spacer (ITS) of nuclear ribosomal DNA (rDNA) among Oesophagostomum asperum isolates from goats in Hunan Province, China. A portion of the cox1 (pcox1), nad1 (pnad1) genes and the ITS (ITS1+5.8S rDNA+ITS2) rDNA were amplified by polymerase chain reaction (PCR) separately from adult O. asperum individuals and the representative amplicons were subjected to sequencing from both directions. The lengths of pcox1, pnad1 and ITS rDNA were 366 bp, 681 bp and 785 bp, respectively. The A+T contents of gene sequences were 71.5–72% for pcox1, 73.7–74.2% for pnad1 and 58–58.8% for ITS rDNA. Intra-specific sequence variations within O. asperum were 0–1.6% for pcox1, 0–1.9% for pnad1 and 0–1.7% for ITS rDNA, while inter-specific sequence differences among members of the genus Oesophagostomum were significantly higher, being 11.1–12.5%, 13.3–17.7% and 8.5–18.6% for pcox1, pnad1 and ITS rDNA, respectively. Phylogenetic analyses using combined sequences of pcox1 and pnad1, with three different computational algorithms (Bayesian inference, maximum likelihood and maximum parsimony), revealed distinct groups with high statistical support. These findings demonstrated the existence of intra-specific variation in mtDNA and rDNA sequences among O. asperum isolates from goats in Hunan Province, China, and have implications for studying molecular epidemiology and population genetics of O. asperum.

scholarly journals Protist community composition during early phytoplankton blooms in the naturally iron-fertilized Kerguelen area (Southern Ocean)

2014 ◽  
Vol 11 (7) ◽  
pp. 11179-11215 ◽  
Author(s):  
C. Georges ◽  
S. Monchy ◽  
S. Genitsaris ◽  
U. Christaki
Keyword(s):  
Southern Ocean ◽  
Community Composition ◽  
Reference Site ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Phytoplankton Blooms ◽  
Natural Iron ◽  
High Nutrient ◽  
Taxonomic Groups ◽  
High Level

Abstract. Microbial eukaryotic community composition was examined by 18S rRNA gene tag pyrosequencing, during the early phase of spring phytoplankton blooms induced by natural iron fertilization, off Kerguelen Island in the Southern Ocean (KEOPS2 cruise). A total of 999 operational taxonomical units (OTUs), affiliated to 30 known high-level taxonomic groups, were retrieved from 16 samples collected in the upper 300 m water column. The alveolata group was the most abundant in terms of sequence number and diversity (696 OTUs). The majority of alveolata sequences were affiliated to Dinophyceae and to two major groups of marine alveolates (MALV-I and MALV-II). In the upper 180 m, only 13% of the OTUs were shared between of the fertilized stations and the reference site characterized by high nutrient low chlorophyll (HNLC) waters. Fungi and Cercozoa were present in iron-fertilized waters, but almost absent in the HNLC samples, while Haptophyta and Chlorophyta characterized the HNLC sample. Finally, the 300 m depth samples of all stations were differentiated by the presence of MALV-II and Radiolaria. Multivariate analysis, examining the level of similarity between different samples, showed that protistan assemblages differed significantly between the HNLC and iron-fertilized stations, but also between the diverse iron-fertilized blooms.

scholarly journals Soil-dwelling polychaetes: enigmatic as ever? Some hints on their phylogenetic relationships as suggested by a maximum parsimony analysis of 18S rRNA gene sequences

2001 ◽  
Vol 70 (3) ◽  
pp. 127-138 ◽  
Author(s):  
Emilia Rota ◽  
Patrick Martin ◽  
Christer Erséus
Keyword(s):  
Phylogenetic Relationships ◽  
Maximum Parsimony ◽  
Systematic Position ◽  
18S Rrna Gene ◽  
Maximum Parsimony Analysis ◽  
Rrna Gene ◽  
Parsimony Analysis ◽  
Data Set ◽  
Independent Evidence ◽  
Rdna Sequences

To re-evaluate the various hypotheses on the systematic position of Parergodrilus heideri Reisinger, 1925 and Hrabeiella periglandulata Pizl & Chalupský, 1984, the sole truly terrestrial non-clitellate annelids known to date, their phylogenetic relationships were investigated using a data set of new 18S rDNA sequences of these and other five relevant annelid taxa, including an unknown species of Ctenodrilidae, as well as homologous sequences already available for 18 polychaetes, one aphanoneuran, 11 clitellates, two pogonophorans, one echiuran, one sipunculan, three molluscs and two arthropods. Two different alignments were constructed, according to an algorithmic method (Clustal W) and on the basis of a secondary structure model (DCSE), A maximum parsimony analysis was performed with arthropods as an unambiguous outgroup. With both alignments, the resulting topology confirms the validity of grouping P. heideri and Stygocapitella subterranean Knöllner, 1934 into the family Parergodrilidae. Hrabeiella periglandulata never clusters with them and its position relative to this and other polychaete families is still obscure, but a close relationship with aphanoneurans is suggested by the most parsimonious trees. All these taxa appear to be far from the Clitellata. Most relationships among polychaetes are not supported by significant bootstrap and Bremer values. These polytomies are corroborated by independent evidence and are interpreted as resulting from an ancient emergence and a rapid radiation of Polychaeta.

Sign in / Sign up

Export Citation Format

Share Document