scholarly journals The small ribosomal subunit RNA isoforms in Plasmodium cynomolgi.

Genetics ◽  
1994 ◽  
Vol 136 (3) ◽  
pp. 857-865 ◽  
Author(s):  
V Corredor ◽  
V Enea
Keyword(s):  
Ribosomal Subunit ◽  
Plasmodium Species ◽  
Single Copy ◽  
Small Subunit ◽  
Rrna Genes ◽  
Last Common Ancestor ◽  
Small Subunit Rrna ◽  
Specific Sequence ◽  
Variable Regions ◽  
Plasmodium Cynomolgi

Abstract We report the isolation, characterization and analysis of the small subunit rRNA genes in Plasmodium cynomolgi (Ceylon). As in other Plasmodium species, these genes are present in low copy number, are unlinked and form two types that are distinct in sequence and are expressed stage specifically. The asexually expressed (type A) genes are present in four copies in the Ceylon- and in five copies in the Berok-strain. Surprisingly, the sexually expressed (type B) gene is present in a single copy. The vast majority of the differences between gene types is confined to the variable regions. The pattern of divergence is different from that observed in Plasmodium berghei or in Plasmodium falciparum. Analysis of the small subunit rRNA sequences of P. cynomolgi, P. berghei and P. falciparum, indicates that the two gene types do not evolve independently but rather interact (through gene conversion or some form of recombination) to such an extent as to erase whatever stage-specific sequence signatures they may have had in the last common ancestor.

Phenotypic effects of targeted mutations in the small subunit rRNA gene of Tetrahymena thermophila

1993 ◽  
Vol 13 (8) ◽  
pp. 4814-4825
Author(s):  
R Sweeney ◽  
L Chen ◽  
M C Yao
Keyword(s):  
Tertiary Structure ◽  
Tetrahymena Thermophila ◽  
Ribosomal Subunit ◽  
Small Subunit ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Small Subunit Rrna ◽  
Variable Regions ◽  
Small Subunit Rrna Gene

Tetrahymena thermophila is an ideal organism with which to study functional aspects of the rRNAs in vivo since the somatic rRNA genes of T. thermophila can be totally replaced by cloned copies introduced via microinjection. In this study, we made small insertions into seven sites within the small subunit rRNA gene and observed their phenotypic effects on transformed cells. Two mutated genes coding for rRNA (rDNAs), both of which bear insertions in highly conserved sequences, failed to transform and are therefore believed to produce nonfunctional rRNAs. Three other altered rDNAs produce functional rRNAs that can substitute for most or all of the cellular rRNA. Two of these bear insertions in highly variable regions, and, surprisingly, the other has an insertion in a region that is well conserved for both sequence and secondary structure among eucaryotes. In addition, two other insertions appear to destabilize rRNAs that contain them. Our findings make predictions concerning the positions of some of these sites within the tertiary structure of the small ribosomal subunit and thus serve as an in vivo test of the existing tertiary structure models for the small subunit rRNA. Our results are in good agreement with expectations based on sequence comparison and in vitro work.

scholarly journals Phenotypic effects of targeted mutations in the small subunit rRNA gene of Tetrahymena thermophila.

1993 ◽  
Vol 13 (8) ◽  
pp. 4814-4825 ◽  
Author(s):  
R Sweeney ◽  
L Chen ◽  
M C Yao
Keyword(s):  
Tertiary Structure ◽  
Tetrahymena Thermophila ◽  
Ribosomal Subunit ◽  
Small Subunit ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Small Subunit Rrna ◽  
Variable Regions ◽  
Small Subunit Rrna Gene

Tetrahymena thermophila is an ideal organism with which to study functional aspects of the rRNAs in vivo since the somatic rRNA genes of T. thermophila can be totally replaced by cloned copies introduced via microinjection. In this study, we made small insertions into seven sites within the small subunit rRNA gene and observed their phenotypic effects on transformed cells. Two mutated genes coding for rRNA (rDNAs), both of which bear insertions in highly conserved sequences, failed to transform and are therefore believed to produce nonfunctional rRNAs. Three other altered rDNAs produce functional rRNAs that can substitute for most or all of the cellular rRNA. Two of these bear insertions in highly variable regions, and, surprisingly, the other has an insertion in a region that is well conserved for both sequence and secondary structure among eucaryotes. In addition, two other insertions appear to destabilize rRNAs that contain them. Our findings make predictions concerning the positions of some of these sites within the tertiary structure of the small ribosomal subunit and thus serve as an in vivo test of the existing tertiary structure models for the small subunit rRNA. Our results are in good agreement with expectations based on sequence comparison and in vitro work.

scholarly journals Development and Application of Small-Subunit rRNA Probes for Assessment of Selected Thiobacillus Species and Members of the Genus Acidiphilium

2000 ◽  
Vol 66 (7) ◽  
pp. 3065-3072 ◽  
Author(s):  
Jordan Peccia ◽  
Eric A. Marchand ◽  
Joann Silverstein ◽  
Mark Hernandez
Keyword(s):  
Acid Mine Drainage ◽  
Mine Drainage ◽  
Small Subunit ◽  
Rrna Genes ◽  
Ribosomal Database Project ◽  
Oligonucleotide Probes ◽  
Small Subunit Rrna ◽  
Variable Regions ◽  
Acid Mine ◽  
Acidophilic Bacteria

ABSTRACT Culture-dependent studies have implicated sulfur-oxidizing bacteria as the causative agents of acid mine drainage and concrete corrosion in sewers. Thiobacillus species are considered the major representatives of the acid-producing bacteria in these environments. Small-subunit rRNA genes from all of the Thiobacillus andAcidiphilium species catalogued by the Ribosomal Database Project were identified and used to design oligonucleotide DNA probes. Two oligonucleotide probes were synthesized to complement variable regions of 16S rRNA in the following acidophilic bacteria:Thiobacillus ferrooxidans and T. thiooxidans(probe Thio820) and members of the genus Acidiphilium(probe Acdp821). Using 32P radiolabels, probe specificity was characterized by hybridization dissociation temperature (Td ) with membrane-immobilized RNA extracted from a suite of 21 strains representing three groups of bacteria. Fluorochrome-conjugated probes were evaluated for use with fluorescent in situ hybridization (FISH) at the experimentally determinedTd s. FISH was used to identify and enumerate bacteria in laboratory reactors and environmental samples. Probing of laboratory reactors inoculated with a mixed culture of acidophilic bacteria validated the ability of the oligonucleotide probes to track specific cell numbers with time. Additionally, probing of sediments from an active acid mine drainage site in Colorado demonstrated the ability to identify numbers of active bacteria in natural environments that contain high concentrations of metals, associated precipitates, and other mineral debris.

scholarly journals Culture-Independent Analysis of Indomethacin-Induced Alterations in the Rat Gastrointestinal Microbiota

2006 ◽  
Vol 72 (10) ◽  
pp. 6707-6715 ◽  
Author(s):  
Andrew B. Dalby ◽  
Daniel N. Frank ◽  
Allison L. St. Amand ◽  
Alison M. Bendele ◽  
Norman R. Pace
Keyword(s):  
Small Intestine ◽  
Lymph Nodes ◽  
Small Subunit ◽  
Rrna Genes ◽  
Small Subunit Rrna ◽  
Mesenteric Lymph Nodes ◽  
Gastrointestinal Microbiota ◽  
Mesenteric Lymph ◽  
Independent Analysis ◽  
Culture Independent

ABSTRACT Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly prescribed for a variety of inflammatory conditions; however, the benefits of this class of drugs are accompanied by deleterious side effects, most commonly gastric irritation and ulceration. NSAID-induced ulceration is thought to be exacerbated by intestinal microbiota, but previous studies have not identified specific microbes that contribute to these adverse effects. In this study, we conducted a culture-independent analysis of ∼1,400 bacterial small-subunit rRNA genes associated with the small intestines and mesenteric lymph nodes of rats treated with the NSAID indomethacin. This is the first molecular analysis of the microbiota of the rat small intestine. A comparison of clone libraries and species-specific quantitative PCR results from rats treated with indomethacin and untreated rats revealed that organisms closely related to Enterococcus faecalis were heavily enriched in the small intestine and mesenteric lymph nodes of the treated rats. These data suggest that treatment of NSAID-induced ulceration may be facilitated by addressing the microbiological imbalances.

scholarly journals Specificity of Associations between Bacteria and the Coral Pocillopora meandrina during Early Development

2012 ◽  
Vol 78 (20) ◽  
pp. 7467-7475 ◽  
Author(s):  
Amy Apprill ◽  
Heather Q. Marlow ◽  
Mark Q. Martindale ◽  
Michael S. Rappé
Keyword(s):  
Small Subunit ◽  
Rrna Genes ◽  
Polymorphism Analysis ◽  
Roseobacter Clade ◽  
Small Subunit Rrna ◽  
Content Type ◽  
Sterile Seawater ◽  
Show Evidence ◽  
Coral Health

ABSTRACTRelationships between corals and specific bacterial associates are thought to play an important role in coral health. In this study, the specificity of bacteria associating with the coralPocillopora meandrinawas investigated by exposing coral embryos to various strains of cultured marine bacteria, sterile seawater, or raw seawater and examining the identity, density, and location of incorporated cells. The isolates utilized in this experiment included members of the Roseobacter and SAR11 clades of theAlphaproteobacteria, aPseudoalteromonasspecies of theGammaproteobacteria, and aSynechococcusspecies of theCyanobacteriaphylum. Based on terminal restriction fragment length polymorphism analysis of small-subunit rRNA genes, similarities in bacterial communities associated with 170-h-old planulae were observed regardless of treatment, suggesting that bacteria may have been externally associated from the outset of the experiment. Microscopic examination ofP. meandrinaplanulae by fluorescencein situhybridization with bacterial and Roseobacter clade-specific oligonucleotide probes revealed differences in the densities and locations of planulae-associated cells. Planulae exposed to either raw seawater or strains ofPseudoalteromonasand Roseobacter harbored the highest densities of internally associated cells, of which 20 to 100% belonged to the Roseobacter clade. Planulae exposed to sterile seawater or strains of the SAR11 clade andSynechococcusdid not show evidence of prominent bacterial associations. Additional analysis of the raw-seawater-exposed planulae via electron microscopy confirmed the presence of internally associated prokaryotic cells, as well as virus-like particles. These results suggest that the availability of specific microorganisms may be an important factor in the establishment of coral-bacterial relationships.

scholarly journals Phytoplankton distribution patterns in the northwestern Sargasso Sea revealed by small subunit rRNA genes from plastids

2011 ◽  
Vol 6 (3) ◽  
pp. 481-492 ◽  
Author(s):  
Alexander H Treusch ◽  
Elif Demir-Hilton ◽  
Kevin L Vergin ◽  
Alexandra Z Worden ◽  
Craig A Carlson ◽  
...  
Keyword(s):  
Distribution Patterns ◽  
Small Subunit ◽  
Rrna Genes ◽  
Sargasso Sea ◽  
Small Subunit Rrna ◽  
Phytoplankton Distribution

The Relationships among Microorganisms in Paddy Soil of Rice Varieties at Sanamchaikate, Chachoengsao

2017 ◽  
Vol 866 ◽  
pp. 144-147
Author(s):  
Duongruitai Nicomrat ◽  
Paisan Kanthang ◽  
Siriphatrc Chamutpong
Keyword(s):  
Paddy Soil ◽  
Small Subunit ◽  
Organic Fertilizers ◽  
Rrna Genes ◽  
Most Probable Number ◽  
Small Subunit Rrna ◽  
Rice Varieties ◽  
Probable Number ◽  
Jasmine Rice ◽  
Ph Range

The research was conducted to understand the diversity of microbial communities in the rice cultivars KDM 105 in the rice fields at Sanamchaikate, Chachoengsao Province. The culturing bacterial community in paddy soil before planting, during the planting and sowing of rice, and after rice collection as well as isolation of free nitrogen fixing bacteria under aerobic and anaerobic conditions were identified by molecular comparision of 16S small subunit rRNA genes as well as species diversity and their richness by Most Probable Number (MPN) method. Culturable bacterial isolates in the soil around the roots of rice varieties were determined for their physical appearances on the solid culture (Plate culturing method) and the microscopic observation under light microscope. It was found that bacteria in the paddy soil complemented with organic fertilizers and no pesticide application for over five years had a pH range from 5.2 to 5.5 cultivated jasmine rice, 8-9 log Units of free N2-fixing bacteria near the roots compared with those in other area having 4-5 log Units. Most of them were identified to be Pseudomonas sp. Microbacterium sp. Bacillus sp. Stenotrophomonas sp. and Burkholderia sp., by homology comparison of 16S rDNA gene at 98, 97, 99, 99.5, and 99%, respectively. This research revealed the recognizable complex and change in soil bacteria presented in paddy ecosystem. In any critical change of to the soil, the study of microbial diversity, compositions and their richness can be further useful for indicating proper soil management.

scholarly journals Comparative analysis of chloroplast genomes for five Dicliptera species (Acanthaceae): molecular structure, phylogenetic relationships, and adaptive evolution

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8450 ◽  
Author(s):  
Sunan Huang ◽  
Xuejun Ge ◽  
Asunción Cano ◽  
Betty Gaby Millán Salazar ◽  
Yunfei Deng
Keyword(s):  
Adaptive Evolution ◽  
Phylogenetic Relationships ◽  
Single Copy ◽  
Rrna Genes ◽  
Trna Genes ◽  
Evolutionary Analysis ◽  
Protein Coding ◽  
Variable Regions ◽  
Protein Coding Genes ◽  
Chloroplast Genomes

The genus Dicliptera (Justicieae, Acanthaceae) consists of approximately 150 species distributed throughout the tropical and subtropical regions of the world. Newly obtained chloroplast genomes (cp genomes) are reported for five species of Dilciptera (D. acuminata, D. peruviana, D. montana, D. ruiziana and D. mucronata) in this study. These cp genomes have circular structures of 150,689–150,811 bp and exhibit quadripartite organizations made up of a large single copy region (LSC, 82,796–82,919 bp), a small single copy region (SSC, 17,084–17,092 bp), and a pair of inverted repeat regions (IRs, 25,401–25,408 bp). Guanine-Cytosine (GC) content makes up 37.9%–38.0% of the total content. The complete cp genomes contain 114 unique genes, including 80 protein-coding genes, 30 transfer RNA (tRNA) genes, and four ribosomal RNA (rRNA) genes. Comparative analyses of nucleotide variability (Pi) reveal the five most variable regions (trnY-GUA-trnE-UUC, trnG-GCC, psbZ-trnG-GCC, petN-psbM, and rps4-trnL-UUA), which may be used as molecular markers in future taxonomic identification and phylogenetic analyses of Dicliptera. A total of 55-58 simple sequence repeats (SSRs) and 229 long repeats were identified in the cp genomes of the five Dicliptera species. Phylogenetic analysis identified a close relationship between D. ruiziana and D. montana, followed by D. acuminata, D. peruviana, and D. mucronata. Evolutionary analysis of orthologous protein-coding genes within the family Acanthaceae revealed only one gene, ycf15, to be under positive selection, which may contribute to future studies of its adaptive evolution. The completed genomes are useful for future research on species identification, phylogenetic relationships, and the adaptive evolution of the Dicliptera species.

scholarly journals Microbial Composition of Near-Boiling Silica-Depositing Thermal Springs throughout Yellowstone National Park

2002 ◽  
Vol 68 (10) ◽  
pp. 5123-5135 ◽  
Author(s):  
Carrine E. Blank ◽  
Sherry L. Cady ◽  
Norman R. Pace
Keyword(s):  
Yellowstone National Park ◽  
National Park ◽  
Hydrogen Oxidation ◽  
Large Subunit ◽  
Microbial Community Composition ◽  
Pcr Amplification ◽  
Small Subunit ◽  
Rrna Genes ◽  
Small Subunit Rrna ◽  
Microbial Composition

ABSTRACT The extent of hyperthermophilic microbial diversity associated with siliceous sinter (geyserite) was characterized in seven near-boiling silica-depositing springs throughout Yellowstone National Park using environmental PCR amplification of small-subunit rRNA genes (SSU rDNA), large-subunit rDNA, and the internal transcribed spacer (ITS). We found that Thermocrinis ruber, a member of the order Aquificales, is ubiquitous, an indication that primary production in these springs is driven by hydrogen oxidation. Several other lineages with no known close relatives were identified that branch among the hyperthermophilic bacteria. Although they all branch deep in the bacterial tree, the precise phylogenetic placement of many of these lineages is unresolved at this time. While some springs contained a fair amount of phylogenetic diversity, others did not. Within the same spring, communities in the subaqueous environment were not appreciably different than those in the splash zone at the edge of the pool, although a greater number of phylotypes was found along the pool's edge. Also, microbial community composition appeared to have little correlation with the type of sinter morphology. The number of cell morphotypes identified by fluorescence in situ hybridization and scanning electron microscopy was greater than the number of phylotypes in SSU clone libraries. Despite little variation in Thermocrinis ruber SSU sequences, abundant variation was found in the hypervariable ITS region. The distribution of ITS sequence types appeared to be correlated with distinct morphotypes of Thermocrinis ruber in different pools. Therefore, species- or subspecies-level divergences are present but not detectable in highly conserved SSU sequences.

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