scholarly journals Cloning of a gene involved in rRNA precursor processing and 23S rRNA cleavage in Rhodobacter capsulatus.

1994 ◽  
Vol 176 (4) ◽  
pp. 1121-1127 ◽  
Author(s):  
E Kordes ◽  
S Jock ◽  
J Fritsch ◽  
F Bosch ◽  
G Klug
Keyword(s):  
Rhodobacter Capsulatus ◽  
23S Rrna ◽  
Precursor Processing ◽  
Rrna Cleavage

scholarly journals RNase III Processing of Intervening Sequences Found in Helix 9 of 23S rRNA in the Alpha Subclass of Proteobacteria

2000 ◽  
Vol 182 (17) ◽  
pp. 4719-4729 ◽  
Author(s):  
Elena Evguenieva-Hackenberg ◽  
Gabriele Klug
Keyword(s):  
Rhodobacter Capsulatus ◽  
23S Rrna ◽  
Recent Attempt ◽  
Rnase Iii ◽  
E Coli ◽  
Rdna Sequences ◽  
Intervening Sequences ◽  
Rna Maturation

ABSTRACT We provide experimental evidence for RNase III-dependent processing in helix 9 of the 23S rRNA as a general feature of many species in the alpha subclass of Proteobacteria(alpha-Proteobacteria). We investigated 12Rhodobacter, Rhizobium,Sinorhizobium, Rhodopseudomonas, andBartonella strains. The processed region is characterized by the presence of intervening sequences (IVSs). The 23S rDNA sequences between positions 109 and 205 (Escherichia coli numbering) were determined, and potential secondary structures are proposed. Comparison of the IVSs indicates very different evolutionary rates in some phylogenetic branches, lateral genetic transfer, and evolution by insertion and/or deletion. We show that the IVS processing inRhodobacter capsulatus in vivo is RNase III-dependent and that RNase III cleaves additional sites in vitro. While all IVS-containing transcripts tested are processed in vitro by RNase III from R. capsulatus, E. coli RNase III recognizes only some of them as substrates and in these substrates frequently cleaves at different scissile bonds. These results demonstrate the different substrate specificities of the two enzymes. Although RNase III plays an important role in the rRNA, mRNA, and bacteriophage RNA maturation, its substrate specificity is still not well understood. Comparison of the IVSs of helix 9 does not hint at sequence motives involved in recognition but reveals that the “antideterminant” model, which represents the most recent attempt to explain the E. coli RNase III specificity in vitro, cannot be applied to substrates derived from alpha-Proteobacteria.

Use of gene probes for the detection of quiescent enteric bacteria in marine and fresh waters

1995 ◽  
Vol 31 (5-6) ◽  
pp. 291-298
Author(s):  
Sally A. Anderson ◽  
Gillian D. Lewis ◽  
Michael N. Pearson
Keyword(s):  
Membrane Filtration ◽  
Enteric Bacteria ◽  
Probe Method ◽  
Detection Methods ◽  
23S Rrna ◽  
Specific Gene ◽  
Gene Probe ◽  
Selective Media ◽  
Selective Enrichment ◽  
E Coli

Specific gene probe detection methods that utilise a non-selective culturing step were tested for the ability to recognise the presence of quiescent enteric bacteria (Escherichia coli and Enterococcus faecalis ) within illuminated freshwater and seawater microcosms. An E. coli specific uidA gene probe and a 23S rRNA oligonucleotide probe for Enterococci were compared with recoveries using membrane filtration and incubation on selective media (mTEC and mE respectively). From these microcosm experiments a greater initial detection (from 4 hours to 1 day) of E. coli and Ent. faecalis using gene probe methods was observed. Additionally, a comparison of E. coli direct viable counts (DVC) in sunlight exposed microcosms with recoveries by selective media and gene probe methods revealed a large number of viable non-culturable cells. This suggests that enumeration of E. coli by a gene probe method is limited by the replication of the bacteria during the initial non-selective enrichment step. The detection of stressed Ent. faecalis by the oligonucleotide gene probe method was significantly greater than recovery on selective mE agar, indicating an Enterococci non-growth phase.

scholarly journals Macrolide-Resistant and Macrolide-Sensitive Mycoplasma pneumoniae Pneumonia in Children Treated Using Early Corticosteroids

2021 ◽  
Vol 10 (6) ◽  
pp. 1309
Author(s):  
Hye Young Han ◽  
Ki Cheol Park ◽  
Eun-Ae Yang ◽  
Kyung-Yil Lee
Keyword(s):  
Mycoplasma Pneumoniae ◽  
Serological Test ◽  
Corticosteroid Treatment ◽  
23S Rrna ◽  
Laboratory Parameters ◽  
The Mean ◽  
Domain V ◽  
Positive Results ◽  
Mycoplasma Pneumoniae Pneumonia

We have found that early corticosteroid therapy was effective for reducing morbidity during five Korea-wide epidemics. We evaluated the clinical and laboratory parameters of 56 children who received early corticosteroid treatment for pneumonia that was caused by macrolide-resistant Mycoplasma pneumoniae (M. pneumoniae) or macrolide-sensitive M. pneumoniae between July 2019 and February 2020. All subjects had dual positive results from a PCR assay and serological test, and received corticosteroids within 24–36 h after admission. Point mutation of residues 2063, 2064, and 2067 was identified in domain V of 23S rRNA. The mean age was 6.8 years and the male:female ratio was 1.2:1 (31:25 patients). Most of the subjects had macrolide-resistant M. pneumoniae (73%), and all mutated strains had the A2063G transition. No significant differences in clinical and laboratory parameters were observed between macrolide-resistant and macrolide-sensitive M. pneumoniae groups that were treated with early dose-adjusted corticosteroids. Higher-dose steroid treatment may be needed for patients who have fever that persists for >48 h or increased biomarkers such as lactate dehydrogenase concentration at follow-up despite a usual dose of steroid therapy.

scholarly journals Mitochondrial genome evolution in pelagophyte algae

2021 ◽  
Author(s):  
Shannon J Sibbald ◽  
Maggie Lawton ◽  
John M Archibald
Keyword(s):  
Mitochondrial Genome ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
23S Rrna ◽  
Mitochondrial Genomes ◽  
Trna Genes ◽  
Unique Region ◽  
Long Read ◽  
Genomic Studies ◽  
Aureoumbra Lagunensis

Abstract The Pelagophyceae are marine stramenopile algae that include Aureoumbra lagunensis and Aureococcus anophagefferens, two microbial species notorious for causing harmful algal blooms. Despite their ecological significance, relatively few genomic studies of pelagophytes have been carried out. To improve understanding of the biology and evolution of pelagophyte algae, we sequenced complete mitochondrial genomes for A. lagunensis (CCMP1510), Pelagomonas calceolata (CCMP1756) and five strains of A. anophagefferens (CCMP1707, CCMP1708, CCMP1850, CCMP1984 and CCMP3368) using Nanopore long-read sequencing. All pelagophyte mitochondrial genomes assembled into single, circular mapping contigs between 39,376 base-pairs (bp) (P. calceolata) and 55,968 bp (A. lagunensis) in size. Mitochondrial genomes for the five A. anophagefferens strains varied slightly in length (42,401 bp—42,621 bp) and were 99.4%-100.0% identical. Gene content and order was highly conserved between the A. anophagefferens and P. calceolata genomes, with the only major difference being a unique region in A. anophagefferens containing DNA adenine and cytosine methyltransferase (dam/dcm) genes that appear to be the product of lateral gene transfer from a prokaryotic or viral donor. While the A. lagunensis mitochondrial genome shares seven distinct syntenic blocks with the other pelagophyte genomes, it has a tandem repeat expansion comprising ∼40% of its length, and lacks identifiable rps19 and glycine tRNA genes. Laterally acquired self-splicing introns were also found in the 23S rRNA (rnl) gene of P. calceolata and the coxI gene of the five A. anophagefferens genomes. Overall, these data provide baseline knowledge about the genetic diversity of bloom-forming pelagophytes relative to non-bloom-forming species.

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