Background: Preserving the optimal quality of DNA and RNA is mandatory for molecular testing in lung adenocarcinoma cytological smears (LACSs).
Methods: DNA and RNA were isolated from 90 frozen unstained and 46 May Grünwald Giemsa (MGG) stained LACSs prepared from bronchial washing (BW), bronchial brushing (BB), and pleural effusion (PE) samples during 3 years. Concentrations of nucleic acids in all LACSs were assessed by spectrophotometric analysis. Fragmentation of DNA and RNA was determined by PCR amplification of selected genes. Amplicons of 100, 200, 300, 400, and 600 bp were used for DNA and 108 bp-long HPRT1 transcript fragment for RNA fragmentation analysis.
Results: Among 90 frozen LACSs, significantly lower DNA concentrations of BB and RNA concentrations of BW samples frozen for 6-10 months were observed in comparison with samples frozen for longer periods (p < .05). Among 46 paired LACSs, 44 (95.7%) frozen and 15 (32.6%) MGG-stained samples showed 600 bp-long DNA amplicons. Statistically significant difference (p < .05) in the fragmentation of DNA between frozen and MGG-stained LACSs was observed (p < .05), with DNA being less fragmented in frozen LACSs. In addition, 33 (71.7%) frozen and 36 (78.2%) MGG-stained LASCs showed HPRT1 gene amplicon of 108 bp. RNA was less fragmented in 3-year old MGG-stained samples than in LACSs frozen for 3 years.
Conclusion: DNA and RNA extracted from frozen and MGG-stained LACSs showed different results depending on the time of storage and/or type of samples, but in general all samples had adequate quantity and quality for downstream molecular testing.
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http://dx.doi.org/10.1002/dc.24896 | DOI Listing |
Nat Commun
December 2024
Department of Pharmacology, Jiangsu Provincial Key Laboratory of Critical Care Medicine, School of Medicine, Southeast University, Nanjing, China.
While circular RNAs (circRNAs) exhibit lower abundance compared to corresponding linear RNAs, they demonstrate potent biological functions. Nevertheless, challenges arise from the low concentration and distinctive structural features of circRNAs, rendering existing methods operationally intricate and less sensitive. Here, we engineer an intelligent tetrahedral DNA framework (TDF) possessing precise spatial pattern-recognition properties with exceptional sensing speed and sensitivity for circRNAs.
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December 2024
Department of Chemical Engineering, Polytechnic School, University of São Paulo, Av. Prof. Luciano Gualberto, Travessa 3, n. 380., São Paulo, SP, CEP 05508-900, Brazil.
16S ribosomal nucleic acid (16S rRNA) analysis allows to specifically target the metabolically active members of microbial communities. The stability of the ratios between target genes in the workflow, which is essential for the bioprocess-relevance of the data derived from this analysis, was investigated using synthetic mock communities constructed by mixing purified 16S rRNA from Bacillus subtilis (Bs), Staphylococcus aureus (Sa), Pseudomonas aeruginosa (Pa), Klebsiella pneumoniae (Kp) and Burkholderia cepacia (Bc) in different proportions. The RT reaction yielded one copy of cDNA per rRNA molecule for Pa, Bc and Sa but only 2/3 of the expected cDNA from 16S rRNAs of Bs and Kp.
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December 2024
Department of Medicine, Columbia Center for Human Development and Stem Cell Therapies, Columbia University Irving Medical Center, New York, NY, USA.
Pluripotent stem cells possess a unique nuclear architecture characterized by a larger nucleus and more open chromatin, which underpins their ability to self-renew and differentiate. Here, we show that the nucleolus-specific RNA helicase DDX18 is essential for maintaining the pluripotency of human embryonic stem cells. Using techniques such as Hi-C, DNA/RNA-FISH, and biomolecular condensate analysis, we demonstrate that DDX18 regulates nucleolus phase separation and nuclear organization by interacting with NPM1 in the granular nucleolar component, driven by specific nucleolar RNAs.
View Article and Find Full Text PDFNat Commun
December 2024
Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA.
The genomes of human gut bacteria in the genus Bacteroides include numerous operons for biosynthesis of diverse capsular polysaccharides (CPSs). The first two genes of each CPS operon encode a locus-specific paralog of transcription elongation factor NusG (called UpxY), which enhances transcript elongation, and a UpxZ protein that inhibits noncognate UpxYs. This process, together with promoter inversions, ensures that a single CPS operon is transcribed in most cells.
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December 2024
Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
The CRISPR-associated endonuclease Cas9 derived from prokaryotes is used as a genome editing, which targets specific genomic loci by single guide RNAs (sgRNAs). The eukaryotes, the target of genome editing, store their genome DNA in chromatin, in which the nucleosome is a basic unit. Despite previous structural analyses focusing on Cas9 cleaving free DNA, structural insights into Cas9 targeting of DNA within nucleosomes are limited, leading to uncertainties in understanding how Cas9 operates in the eukaryotic genome.
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