scholarly journals Intra-host symbiont diversity and extended symbiont maintenance in photosymbiotic Acantharea (clade F)

2018 ◽  
Author(s):  
Margaret Mars Brisbin ◽  
Lisa Y. Mesrop ◽  
Mary M. Grossmann ◽  
Satoshi Mitarai
Keyword(s):  
Community Composition ◽  
Fluorescent Microscopy ◽  
18S Rrna Gene ◽  
Model Systems ◽  
Reproductive Capacity ◽  
Rrna Gene ◽  
Viral Lysis ◽  
Selective Staining ◽  
Constitute Model ◽  
Multiple Species

AbstractPhotosymbiotic protists contribute to surface primary production in low-nutrient, open-ocean ecosystems and constitute model systems for studying plastid acquisition via endosymbiosis. Little is known, however, about host-symbiont dynamics in these important relationships, and whether these symbioses constitute mutualisms is debated. In this study, we applied single-cell sequencing methods and advanced fluorescent microscopy to investigate host-symbiont dynamics in clade F acantharians, a major group of photosymbiotic protists in oligotrophic subtropical gyres. We amplified the 18S rRNA gene from single acantharian hosts and environmental samples to assess intra-host symbiont diversity and to determine whether intra-host symbiont community composition directly reflects the available symbiont community in the surrounding environment. Our results demonstrate that clade F acantharians simultaneously host multiple species from the haptophyte genera Phaeocystis and Chrysochromulina. The intra-host symbiont community composition was distinct from the external free-living symbiont community, suggesting that these acantharians maintain symbionts for extended periods of time. After selective staining of digestive organelles, fluorescent confocal microscopy showed that symbionts were not being systematically digested, which is consistent with extended symbiont maintenance within hosts. Extended maintenance within hosts may benefit symbionts through protection from grazing or viral lysis, and therefore dispersal, provided that symbionts retain reproductive capacity.

scholarly journals Short-term responses to ocean acidification: effects on relative abundance of eukaryotic plankton from the tropical Timor Sea

2020 ◽  
Author(s):  
Janina Rahlff ◽  
Sahar Khodami ◽  
Lisa Voskuhl ◽  
Matthew P. Humphreys ◽  
Christian Stolle ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Community Composition ◽  
Hypervariable Region ◽  
18S Rrna Gene ◽  
Marine Biodiversity ◽  
Rrna Gene ◽  
Tropical Regions ◽  
Timor Sea ◽  
Decreasing Ph ◽  
Species Specific

ABSTRACTAnthropogenic carbon dioxide (CO2) emissions drive climate change and pose one of the major challenges of our century. The effects of increased CO2 in the form of ocean acidification (OA) on the communities of marine planktonic eukaryotes in tropical regions such as the Timor Sea are barely understood. Here, we show the effects of high CO2 (pCO2=1823±161 μatm, pHT=7.46±0.05) versus in situ CO2 (pCO2=504±42 μatm, pHT=7.95±0.04) seawater on the community composition of marine planktonic eukaryotes immediately and after 48 hours of treatment exposure in a shipboard microcosm experiment. Illumina sequencing of the V9 hypervariable region of 18S rRNA (gene) was used to study the eukaryotic community composition. Down-regulation of extracellular carbonic anhydrase occurred faster in the high CO2 treatment. Increased CO2 significantly suppressed the relative abundances of different eukaryotic operational taxonomic units (OTUs), including important primary producers. These effects were consistent between abundant (DNA-based) and active (cDNA-based) taxa after 48 hours, e.g., for the diatoms Trieres chinensis and Stephanopyxis turris. Effects were also very species-specific among different diatoms. Planktonic eukaryotes showed adaptation to the CO2 treatment over time, but many OTUs were adversely affected by decreasing pH. OA effects might fundamentally impact the base of marine biodiversity, suggesting profound outcomes for food web functioning in the future ocean.

Phylogenetic identification of Pneumocystis murina sp. nov., a new species in laboratory mice

Microbiology ◽  
2004 ◽  
Vol 150 (5) ◽  
pp. 1153-1165 ◽  
Author(s):  
Scott P. Keely ◽  
Jared M. Fischer ◽  
Melanie T. Cushion ◽  
James R. Stringer
Keyword(s):  
Phylogenetic Trees ◽  
Statistical Tests ◽  
Pneumocystis Carinii ◽  
Sequence Divergence ◽  
18S Rrna Gene ◽  
Genetic Distances ◽  
Rrna Gene ◽  
Gene Trees ◽  
Laboratory Mice ◽  
Multiple Species

Pneumocystis is a fungal genus that contains multiple species. One member of the genus that has not been formally analysed for its phylogenetic relationships and possible species status is the Pneumocystis found in laboratory mice, Pneumocystis murina sp. nov. (type strain ATCC PRA-111T=CBS 114898T), formerly known as Pneumocystis carinii f. sp. muris. To advance research in this area, approximately 3000 bp of additional DNA sequence were obtained from the locus encoding rRNAs. This sequence and others were used to determine genetic distances between P. murina and other members of the genus. These distances indicated that P. murina DNA is most similar to that of the species of Pneumocystis found in laboratory rats. Nevertheless, P. murina is at least as diverged from these other Pneumocystis species as species in other fungal genera are from each other. The 18S rRNA gene sequence divergence exhibited by P. murina could not be ascribed to accelerated evolution of this gene as similar levels of divergence were observed at seven other loci. When five genes were used to construct phylogenetic trees for five Pneumocystis taxa, including P. murina, all the trees had the same topology, indicating that genes do not flow among these taxa. The gene trees were all strongly supported by statistical tests. When sequences from the rRNA-encoding locus were used to estimate the time of divergence of P. murina, the results indicated that P. murina is as old as the mouse. Taken together, these data support previous recognition of multiple species in the genus and indicate that P. murina is a phylogenetic species as well.

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 Feasibility of Assessing the Community Composition of Prasinophytes at the Helgoland Roads Sampling Site with a DNA Microarray

2008 ◽  
Vol 74 (17) ◽  
pp. 5305-5316 ◽  
Author(s):  
Christine Gescher ◽  
Katja Metfies ◽  
Stephan Frickenhaus ◽  
Britta Knefelkamp ◽  
Karen H. Wiltshire ◽  
...  
Keyword(s):  
Community Composition ◽  
Dna Microarrays ◽  
Time Series Data ◽  
Sampling Site ◽  
18S Rrna Gene ◽  
Series Data ◽  
Rrna Gene ◽  
The North ◽  
Algal Group ◽  
The North Sea

ABSTRACT The microalgal class Prasinophyceae (Chlorophyta) contains several picoeukaryotic species, which are known to be common in temperate and cold waters and have been observed to constitute major fractions of marine picoplankton. However, reliable detection and classification of prasinophytes are mainly hampered by their small size and few morphological markers. Consequently, very little is known about the abundance and ecology of the members of this class. In order to facilitate the assessment of the abundance of the Prasinophyceae, we have designed and evaluated an 18S rRNA gene-targeted oligonucleotide microarray consisting of 21 probes targeting different taxonomic levels of prasinophytes. The microarray contains both previously published probes from other hybridization methods and new probes, which were designed for novel prasinophyte groups. The evaluation of the probe set was done under stringent conditions with 18S PCR fragments from 20 unialgal reference cultures used as positive targets. This microarray has been applied to assess the community composition of prasinophytes at Helgoland, an island in the North Sea where time series data are collected and analyzed daily but only for the nano- and microplankton-size fractions. There is no identification of prasinophytes other than to record them numerically in the flagellate fraction. The samples were collected every 2 weeks between February 2004 and December 2006. The study here demonstrates the potential of DNA microarrays to be applied as a tool for quick general monitoring of this important picoplanktonic algal group.

scholarly journals Surveillance of Giardia and Cryptosporidium in sewage from an urban area in Brazil

2019 ◽  
Vol 28 (2) ◽  
pp. 291-297 ◽  
Author(s):  
Felippe Danyel Cardoso Martins ◽  
Winni Alves Ladeia ◽  
Roberta dos Santos Toledo ◽  
João Luis Garcia ◽  
Italmar Teodorico Navarro ◽  
...  
Keyword(s):  
18S Rrna ◽  
Fragment Length Polymorphism ◽  
Sewage Water ◽  
18S Rrna Gene ◽  
Rrna Gene ◽  
Protozoan Parasites ◽  
Treated Sewage ◽  
Multiple Species ◽  
Pcr Targeting

Abstract Cryptosporidium and Giardia are protozoan parasites that cause diarrhea in humans and animals. Molecular characterization of these pathogens in sewage may provide insight on their occurrence and prevalence in Brazil. This study aimed to investigate the presence of Giardia and Cryptosporidium in raw and treated sewage from Londrina, Paraná, Brazil. Samples were collected every two weeks during a year. Samples were concentrated, then DNA was extracted and subjected to a nested PCR targeting the Giardia 18S rRNA gene and the Cryptosporidium 18S rRNA gene. Species of Cryptosporidium were characterized by restriction fragment length polymorphism (RFLP). All raw sewage and 76% of the treated sewage were positive for Giardia; 84% of raw sewage samples and 8% of treated sewage were positive for Cryptosporidium. C. muris, C. hominis, C. baileyi, C. parvum and C. suis were detected in 100%, 19%, 9%, 9% and 4% of raw sewage, respectively. C. muris was the only species found in treated sewage. Multiple species of Cryptosporidium were present in 19.04% of the raw sewage. Treated sewage water can pose a threat to human health. The speciation of Cryptosporidium revealed the presence of non-common zoonotic species as C. suis and C. muris.

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

2014 ◽  
Vol 11 (20) ◽  
pp. 5847-5863 ◽  
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 Benchmarking laboratory processes to characterise low-biomass respiratory microbiota

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Raiza Hasrat ◽  
Jolanda Kool ◽  
Wouter A. A. de Steenhuijsen Piters ◽  
Mei Ling J. N. Chu ◽  
Sjoerd Kuiling ◽  
...  
Keyword(s):  
Microbial Community ◽  
Community Composition ◽  
Microbial Community Composition ◽  
Positive Control ◽  
Rrna Gene ◽  
Elution Buffer ◽  
Community Profile ◽  
Microbial Community Profile ◽  
Microbial Dna ◽  
Pcr Conditions

AbstractThe low biomass of respiratory samples makes it difficult to accurately characterise the microbial community composition. PCR conditions and contaminating microbial DNA can alter the biological profile. The objective of this study was to benchmark the currently available laboratory protocols to accurately analyse the microbial community of low biomass samples. To study the effect of PCR conditions on the microbial community profile, we amplified the 16S rRNA gene of respiratory samples using various bacterial loads and different number of PCR cycles. Libraries were purified by gel electrophoresis or AMPure XP and sequenced by V2 or V3 MiSeq reagent kits by Illumina sequencing. The positive control was diluted in different solvents. PCR conditions had no significant influence on the microbial community profile of low biomass samples. Purification methods and MiSeq reagent kits provided nearly similar microbiota profiles (paired Bray–Curtis dissimilarity median: 0.03 and 0.05, respectively). While profiles of positive controls were significantly influenced by the type of dilution solvent, the theoretical profile of the Zymo mock was most accurately analysed when the Zymo mock was diluted in elution buffer (difference compared to the theoretical Zymo mock: 21.6% for elution buffer, 29.2% for Milli-Q, and 79.6% for DNA/RNA shield). Microbiota profiles of DNA blanks formed a distinct cluster compared to low biomass samples, demonstrating that low biomass samples can accurately be distinguished from DNA blanks. In summary, to accurately characterise the microbial community composition we recommend 1. amplification of the obtained microbial DNA with 30 PCR cycles, 2. purifying amplicon pools by two consecutive AMPure XP steps and 3. sequence the pooled amplicons by V3 MiSeq reagent kit. The benchmarked standardized laboratory workflow presented here ensures comparability of results within and between low biomass microbiome studies.

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