The GTP responsiveness of PI5P4Kβ evolved from a compromised trade-off between activity and specificity

Unlike most kinases, phosphatidylinositol 5-phosphate 4-kinase β (PI5P4Kβ) utilizes GTP as a physiological phosphate donor and regulates cell growth under stress (i.e., GTP-dependent stress resilience). However, the genesis and evolution of its GTP responsiveness remain unknown. Here, we reveal that PI5P4Kβ has acquired GTP preference by generating a short dual-nucleotide-recognizing motif called the guanine efficient association (GEA) motif. Comparison of nucleobase recognition with 660 kinases and 128 G proteins has uncovered that most kinases and PI5P4Kβ use their main-chain atoms for adenine recognition, while the side-chain atoms are required for guanine recognition. Mutational analysis of the GEA motif revealed that the acquisition of GTP reactivity is accompanied by an extended activity toward inosine triphosphate (ITP) and xanthosine triphosphate (XTP). Along with the evolutionary analysis data that point to strong negative selection of the GEA motif, these results suggest that the GTP responsiveness of PI5P4Kβ has evolved from a compromised trade-off between activity and specificity, underpinning the development of the GTP-dependent stress resilience.

MinION, a portable long-read sequencer, enables rapid vaginal microbiota analysis in a clinical setting

Background

It has been suggested that the local microbiota in the reproductive organs is relevant to women's health and may also affect pregnancy outcomes. Analysis of partial 16S ribosomal RNA (rRNA) gene sequences generated by short-read sequencers has been used to identify vaginal and endometrial microbiota, but it requires a long time to obtain the results, making it unsuitable for rapid bacterial identification from a small specimen amount in a clinical context.

Methods

We developed a simple workflow using the nanopore sequencer MinION that allows high-resolution and rapid differentiation of vaginal microbiota. Vaginal samples collected from 18 participants were subjected to DNA extraction and full-length 16S rRNA gene sequencing with MinION.

Results

The principal coordinate analysis showed no differences in the bacterial compositions regardless of the sample collection method. The analysis of vaginal microbiota could be completed with a total analysis time of approximately four hours, allowing same-day results. Taxonomic profiling by MinION sequencing revealed relatively low diversity of the vaginal bacterial community, identifying the prevailing Lactobacillus species and several causative agents of bacterial vaginosis.

Conclusions

Full-length 16S rRNA gene sequencing analysis with MinION provides a rapid means for identifying vaginal bacteria with higher resolution. Species-level profiling of human vaginal microbiota by MinION sequencing can allow the analysis of associations with conditions such as genital infections, endometritis, and threatened miscarriage.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-022-01218-8.

Uhrf1 governs the proliferation and differentiation of muscle satellite cells

DNA methylation is an essential form of epigenetic regulation responsible for cellular identity. In muscle stem cells, termed satellite cells, DNA methylation patterns are tightly regulated during differentiation. However, it is unclear how these DNA methylation patterns affect the function of satellite cells. We demonstrate that a key epigenetic regulator, ubiquitin like with PHD and RING finger domains 1 (Uhrf1), is activated in proliferating myogenic cells but not expressed in quiescent satellite cells or differentiated myogenic cells in mice. Ablation of Uhrf1 in mouse satellite cells impairs their proliferation and differentiation, leading to failed muscle regeneration. Uhrf1-deficient myogenic cells exhibited aberrant upregulation of transcripts, including Sox9, with the reduction of DNA methylation level of their promoter and enhancer region. These findings show that Uhrf1 is a critical epigenetic regulator of proliferation and differentiation in satellite cells, by controlling cell-type-specific gene expression via maintenance of DNA methylation.

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Uhrf1 is activated in proliferating myogenic cells

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Uhrf1 in satellite cells is required for muscle regeneration

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Ablation of Uhrf1 in satellite cells impairs their proliferation and differentiation

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Uhrf1 controls cell-type-specific transcripts via maintenance of DNA methylation

The SARS-CoV-2 Lambda variant exhibits enhanced infectivity and immune resistance

SARS-CoV-2 Lambda, a variant of interest, has spread in some South American countries; however, its virological features and evolutionary traits remain unclear. In this study, we use pseudoviruses and reveal that the spike protein of the Lambda variant is more infectious than that of other variants due to the T76I and L452Q mutations. The RSYLTPGD246-253N mutation, a unique 7-amino acid deletion in the N-terminal domain of the Lambda spike protein, is responsible for evasion from neutralizing antibodies and further augments antibody-mediated enhancement of infection. Although this mutation generates a nascent N-linked glycosylation site, the additional N-linked glycan is dispensable for the virological property conferred by this mutation. Since the Lambda variant has dominantly spread according to the increasing frequency of the isolates harboring the RSYLTPGD246-253N mutation, our data suggest that the RSYLTPGD246-253N mutation is closely associated with the substantial spread of the Lambda variant in South America.

Enhanced fusogenicity and pathogenicity of SARS-CoV-2 Delta P681R mutation

During the current coronavirus disease 2019 (COVID-19) pandemic, a variety of mutations have accumulated in the viral genome of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and, at the time of writing, four variants of concern are considered to be potentially hazardous to human society¹. The recently emerged B.1.617.2/Delta variant of concern is closely associated with the COVID-19 surge that occurred in India in the spring of 2021 (ref. ²). However, the virological properties of B.1.617.2/Delta remain unclear. Here we show that the B.1.617.2/Delta variant is highly fusogenic and notably more pathogenic than prototypic SARS-CoV-2 in infected hamsters. The P681R mutation in the spike protein, which is highly conserved in this lineage, facilitates cleavage of the spike protein and enhances viral fusogenicity. Moreover, we demonstrate that the P681R-bearing virus exhibits higher pathogenicity compared with its parental virus. Our data suggest that the P681R mutation is a hallmark of the virological phenotype of the B.1.617.2/Delta variant and is associated with enhanced pathogenicity.

Structural variation of the 3-acetamido-4,5,6-trihydroxyazepane iminosugar through epimerization and C-alkylation leads to low micromolar HexAB and NagZ inhibitors

We report the synthesis of seven-membered iminosugars derived from a 3S-acetamido-4R,5R,6S-trihydroxyazepane scaffold and their evaluation as inhibitors of functionally related exo-N-acetylhexosaminidases including human O-GlcNAcase (OGA), human lysosomal β-hexosaminidase (HexAB), and Escherichia coli NagZ. Capitalizing on the flexibility of azepanes and the active site tolerances of hexosaminidases, we explore the effects of epimerization of stereocenters at C-3, C-5 and C-6 and C-alkylation at the C-2 or C-7 positions. Accordingly, epimerization at C-6 (L-ido) and at C-5 (D-galacto) led to selective HexAB inhibitors whereas introduction of a propyl group at C-7 on the C-3 epimer furnished a potent NagZ inhibitor.

Neutralization of the SARS-CoV-2 Mu Variant by Convalescent and Vaccine Serum

On August 30, 2021, the WHO classified the SARS-CoV-2 Mu variant (B.1.621 lineage) as a new variant of interest. The WHO defines “comparative assessment of virus characteristics and public health risks” as primary action in response to the emergence of new SARS-CoV-2 variants. Here, we demonstrate that the Mu variant is highly resistant to sera from COVID-19 convalescents and BNT162b2-vaccinated individuals. Direct comparison of different SARS-CoV-2 spike proteins revealed that Mu spike is more resistant to serum-mediated neutralization than all other currently recognized variants of interest (VOI) and concern (VOC). This includes the Beta variant (B.1.351) that has been suggested to represent the most resistant variant to convalescent and vaccinated sera to date (e.g., Collier et al, Nature, 2021; Wang et al, Nature, 2021). Since breakthrough infection by newly emerging variants is a major concern during the current COVID-19 pandemic (Bergwerk et al., NEJM, 2021), we believe that our findings are of significant public health interest. Our results will help to better assess the risk posed by the Mu variant for vaccinated, previously infected and naïve populations.

An ancient retroviral RNA element hidden in mammalian genomes and its involvement in co-opted retroviral gene regulation

Background

Retroviruses utilize multiple unique RNA elements to control RNA processing and translation. However, it is unclear what functional RNA elements are present in endogenous retroviruses (ERVs). Gene co-option from ERVs sometimes entails the conservation of viral cis-elements required for gene expression, which might reveal the RNA regulation in ERVs.

Results

Here, we characterized an RNA element found in ERVs consisting of three specific sequence motifs, called SPRE. The SPRE-like elements were found in different ERV families but not in any exogenous viral sequences examined. We observed more than a thousand of copies of the SPRE-like elements in several mammalian genomes; in human and marmoset genomes, they overlapped with lineage-specific ERVs. SPRE was originally found in human syncytin-1 and syncytin-2. Indeed, several mammalian syncytin genes: mac-syncytin-3 of macaque, syncytin-Ten1 of tenrec, and syncytin-Car1 of Carnivora, contained the SPRE-like elements. A reporter assay revealed that the enhancement of gene expression by SPRE depended on the reporter genes. Mutation of SPRE impaired the wild-type syncytin-2 expression while the same mutation did not affect codon-optimized syncytin-2, suggesting that SPRE activity depends on the coding sequence.

Conclusions

These results indicate multiple independent invasions of various mammalian genomes by retroviruses harboring SPRE-like elements. Functional SPRE-like elements are found in several syncytin genes derived from these retroviruses. This element may facilitate the expression of viral genes, which were suppressed due to inefficient codon frequency or repressive elements within the coding sequences. These findings provide new insights into the long-term evolution of RNA elements and molecular mechanisms of gene expression in retroviruses.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12977-021-00580-2.

Tea crude extracts effectively inactivate severe acute respiratory syndrome coronavirus 2

It is well known that black and green tea extracts, particularly polyphenols, have antimicrobial activity against various pathogenic microbes including viruses. However, there is limited data on the antiviral activity against severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), which emerged rapidly in China in late 2019 and which has been responsible for coronavirus disease 2019 (COVID‐19) pandemic globally. In this study, 20 compounds and three extracts were obtained from black and green tea and found that three tea extracts showed significant antiviral activity against SARS‐CoV‐2, whereby the viral titre decreased about 5 logs TCID₅₀ per ml by 1·375 mg ml⁻¹ black tea extract and two‐fold diluted tea bag infusion obtained from black tea when incubated at 25°C for 10 s. However, when concentrations of black and green tea extracts were equally adjusted to 344 µg ml⁻¹, green tea extracts showed more antiviral activity against SARS‐CoV‐2. This simple and highly respected beverage may be a cheap and widely acceptable means to reduce SARS‐CoV‐2 viral burden in the mouth and upper gastrointestinal and respiratory tracts in developed as well as developing countries.

A novel class of small tRNA-like noncoding transcripts arising from the human NEAT1-MALAT1 region critically influences innate immunity and angiogenesis

Background

The evolutionary conserved NEAT1-MALAT1 gene cluster encounters high interest in cardiovascular medicine and oncology. The cluster generates large primary transcripts which remain nuclear, whereas novel tRNA-like transcripts (mascRNA, menRNA) enzymatically generated from these precursors translocate to the cytosol. We previously found that NEAT1 and MALAT1 deficient mice display accelerated atherosclerosis and vascular inflammation due to immune dysfunctions.

Methods

While the previously investigated mice were deficient in the entire NEAT1 or MALAT1 locus, here we aimed to selectively disrupt only tRNA-like transcripts “menRNA” arising from NEAT1, or “mascRNA” arising from MALAT1. To none of these a biological function has been assigned so far. Both lncRNAs give rise to transcripts of vastly different size (NEAT1: 23kb MENb, 3.7kb MENe, 59nt “menRNA”; MALAT1: 8.3 kb primary, 59nt “mascRNA”), and traditional knockout methods are unable to selectively inactivate one of the small transcripts only. Through CRISPR/Cas9 editing we therefore developed human monocyte-macrophage cell lines with short deletions in the respective tRNA-encoding sequences to disrupt normal menRNA or mascRNA formation, respectively. These editing procedures do not affect transcription of the respective lncRNA parent transcripts, and also not disturb regular formation of the triple-helix structures at their 3'-ends which support stabilization of the respective lncRNAs (Fig. 1).

Results

We found the tRNA-like transcripts menRNA and mascRNA critically influence innate immunity and angiogenesis. In addition to common anomalies resulting from their selective CRISPR-Cas9 mediated deletion (Fig. 1), there are specific disturbances associated with either Δmasc or Δmen cells (Fig. 2).

Both ΔmascRNA and ΔmenRNA human monocytes show profoundly altered ribosomal RNA/protein and tRNA-modifying enzyme expression, display anomalous growth/ angiogenetic factor expression, fundamentally change angiogenetic patterns in co-cultures with human endothelial cells, and have gravely disturbed innate immune responses (LPS, DNA and RNA viruses) (Fig. 1).

CRISPR-engineered ΔmenRNA cells share remakable similarities with human post-MI PBMCs, suggesting the NEAT1-menRNA system may significantly contribute to post-MI residual inflammatory risk despite optimal standard therapy (Fig. 2).

Conclusions

Beyond prior work in knockout mice documenting immune function of the NEAT1-MALAT1 cluster, the current study identifies menRNA and mascRNA as important novel components of human innate immunity with relevance for angiogenetic processes. These data provide a second mechanistic link for the apparent relevance of the NEAT1-MALAT1 gene cluster in cardiovascular and malignant diseases. As prototypes of a novel class of small noncoding RNAs (distinct from miRNAs and siRNAs) they may constitute cytosolic therapeutic targets.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): DZHK Shared Expertise Project/B19-006_SE/FKZ 81X2100257/Transcriptome analysis of circulating immune cells to improve the assessment of prognosis and the response to novel anti-inflammatory treatments after myocardial infarction Figure 1. Common anomaliesFigure 2. Specific anomalies

Accuracy in Facial Trustworthiness Impressions: Kernel of Truth or Modern Physiognomy? A Meta-Analysis

Being able to identify trustworthy strangers is a critical social skill. However, whether such impressions are accurate is debatable. Critically, the field currently lacks a quantitative summary of the evidence. To address this gap, we conducted two meta-analyses. We tested whether there is a correlation between perceived and actual trustworthiness across faces, and whether perceivers show above-chance accuracy at assessing trustworthiness. Both meta-analyses revealed significant, modest accuracy (face level, r = .14; perceiver level, r = .27). Perceiver-level effects depended on domain, with aggressiveness and sexual unfaithfulness having stronger effects than agreeableness, criminality, financial reciprocity, and honesty. We also applied research weaving to map the literature, revealing potential biases, including a preponderance of Western studies, a lack of "cross-talk" between research groups, and clarity issues. Overall, this modest accuracy is unlikely to be of practical utility. Moreover, we strongly urge the field to improve reporting standards and generalizability of the results.

Sequence Compression Benchmark (SCB) database-A comprehensive evaluation of reference-free compressors for FASTA-formatted sequences

Background

Nearly all molecular sequence databases currently use gzip for data compression. Ongoing rapid accumulation of stored data calls for a more efficient compression tool. Although numerous compressors exist, both specialized and general-purpose, choosing one of them was difficult because no comprehensive analysis of their comparative advantages for sequence compression was available.

Findings

We systematically benchmarked 430 settings of 48 compressors (including 29 specialized sequence compressors and 19 general-purpose compressors) on representative FASTA-formatted datasets of DNA, RNA, and protein sequences. Each compressor was evaluated on 17 performance measures, including compression strength, as well as time and memory required for compression and decompression. We used 27 test datasets including individual genomes of various sizes, DNA and RNA datasets, and standard protein datasets. We summarized the results as the Sequence Compression Benchmark database (SCB database, http://kirr.dyndns.org/sequence-compression-benchmark/), which allows custom visualizations to be built for selected subsets of benchmark results.

Conclusion

We found that modern compressors offer a large improvement in compactness and speed compared to gzip. Our benchmark allows compressors and their settings to be compared using a variety of performance measures, offering the opportunity to select the optimal compressor on the basis of the data type and usage scenario specific to a particular application.

Plasmid analysis of NDM metallo-β-lactamase-producing Enterobacterales isolated in Vietnam

Carbapenem-resistant Enterobacterales (CRE) represent a serious threat to public health due to the lack of treatment and high mortality. The rate of antimicrobial resistance of Enterobacterales isolates to major antimicrobials, including carbapenems, is much higher in Vietnam than in Western countries, but the reasons remain unknown due to the lack of genomic epidemiology research. A previous study suggested that carbapenem resistance genes, such as the carbapenemase gene blaNDM, spread via plasmids among Enterobacterales in Vietnam. In this study, we characterized blaNDM-carrying plasmids in Enterobacterales isolated in Vietnam, and identified several possible cases of horizontal transfer of plasmids both within and among species of bacteria. Twenty-five carbapenem-nonsusceptible isolates from a medical institution in Hanoi were sequenced on Illumina short-read sequencers, and 13 blaNDM-positive isolates, including isolates of Klebsiella pneumoniae, Escherichia coli, Citrobacter freundii, Morganella morganii, and Proteus mirabilis, were further sequenced on an Oxford Nanopore Technologies long-read sequencer to obtain complete plasmid sequences. Almost identical 73 kb IncFII(pSE11)::IncN hybrid plasmids carrying blaNDM-1 were found in a P. mirabilis isolate and an M. morganii isolate. A 112 kb IncFII(pRSB107)::IncN hybrid plasmid carrying blaNDM-1 in an E. coli isolate had partially identical sequences with a 39 kb IncR plasmid carrying blaNDM-1 and an 88 kb IncFII(pHN7A8)::IncN hybrid plasmid in a C. freundii isolate. 148-149 kb IncFIA(Hl1)::IncA/C2 plasmids and 75-76 kb IncFII(Yp) plasmids, both carrying blaNDM-1 were shared among three sequence type 11 (ST11) isolates and three ST395 isolates of K. pneumoniae, respectively. Most of the plasmids co-carried genes conferring resistance to clinically relevant antimicrobials, including third-generation cephalosporins, aminoglycosides, and fluoroquinolones, in addition to blaNDM-1. These results provide insight into the genetic basis of CRE in Vietnam, and could help control nosocomial infections.

SARS-CoV-2 spike L452R variant evades cellular immunity and increases infectivity

Many SARS-CoV-2 variants with naturally acquired mutations have emerged. These mutations can affect viral properties such as infectivity and immune resistance. Although the sensitivity of naturally occurring SARS-CoV-2 variants to humoral immunity has been investigated, sensitivity to human leukocyte antigen (HLA)-restricted cellular immunity remains largely unexplored. Here, we demonstrate that two recently emerging mutations in the receptor-binding domain of the SARS-CoV-2 spike protein, L452R (in B.1.427/429 and B.1.617) and Y453F (in B.1.1.298), confer escape from HLA-A24-restricted cellular immunity. These mutations reinforce affinity toward the host entry receptor ACE2. Notably, the L452R mutation increases spike stability, viral infectivity, viral fusogenicity, and thereby promotes viral replication. These data suggest that HLA-restricted cellular immunity potentially affects the evolution of viral phenotypes and that a further threat of the SARS-CoV-2 pandemic is escape from cellular immunity.

Circular dichroism and resonance Raman spectroscopies of bacteriochlorophyll b-containing LH1-RC complexes

The core light-harvesting complexes (LH1) in bacteriochlorophyll (BChl) b-containing purple phototrophic bacteria are characterized by a near-infrared absorption maximum around 1010 nm. The determinative cause for this ultra-redshift remains unclear. Here, we present results of circular dichroism (CD) and resonance Raman measurements on the purified LH1 complexes in a reaction center-associated form from a mesophilic and a thermophilic Blastochloris species. Both the LH1 complexes displayed purely positive CD signals for their Q_y transitions, in contrast to those of BChl a-containing LH1 complexes. This may reflect differences in the conjugation system of the bacteriochlorin between BChl b and BChl a and/or the differences in the pigment organization between the BChl b- and BChl a-containing LH1 complexes. Resonance Raman spectroscopy revealed remarkably large redshifts of the Raman bands for the BChl b C3-acetyl group, indicating unusually strong hydrogen bonds formed with LH1 polypeptides, results that were verified by a published structure. A linear correlation was found between the redshift of the Raman band for the BChl C3-acetyl group and the change in LH1-Q_y transition for all native BChl a- and BChl b-containing LH1 complexes examined. The strong hydrogen bonding and π-π interactions between BChl b and nearby aromatic residues in the LH1 polypeptides, along with the CD results, provide crucial insights into the spectral and structural origins for the ultra-redshift of the long-wavelength absorption maximum of BChl b-containing phototrophs.

HERV-Derived Ervpb1 Is Conserved in Simiiformes, Exhibiting Expression in Hematopoietic Cell Lineages Including Macrophages

(1) Background: The ERVPb1 gene in humans is derived from an envelope (Env) gene of a human endogenous retrovirus group, HERV-P(b). The ERVPb1 gene reportedly has a conserved open reading frame (ORF) in Old World monkeys. Although its forced expression led to cell-fusion in an ex vivo cell culture system, like other Env-derived genes such as syncytin-1 and -2, its mRNA expression is not placenta-specific, but almost ubiquitous, albeit being quite low in human tissues and organs, implying a distinct role for ERVPb1. (2) Methods: To elucidate the cell lineage(s) in which the ERVPb1 protein is translated in human development, we developed a novel, highly sensitive system for detecting HERV-derived proteins/peptides expressed in the tissue differentiation process of human induced pluripotent stem cells (iPSCs). (3) Results: We first determined that ERVPb1 is also conserved in New World monkeys. Then, we showed that the ERVPb1 protein is translated from a uniquely spliced ERVPb1 transcript in hematopoietic cell lineages, including a subset of macrophages, and further showed that its mRNA expression is upregulated by lipopolysaccharide (LPS) stimulation in primary human monocytes. (4) Conclusions: ERVPb1 is unique to Simiiformes and actually translated in hematopoietic cell lineages, including a subset of macrophages.

Sarbecovirus ORF6 proteins hamper induction of interferon signaling

The presence of an ORF6 gene distinguishes sarbecoviruses such as severe acute respiratory syndrome coronavirus (SARS-CoV) and SARS-CoV-2 from other betacoronaviruses. Here we show that ORF6 inhibits induction of innate immune signaling, including upregulation of type I interferon (IFN) upon viral infection as well as type I and III IFN signaling. Intriguingly, ORF6 proteins from SARS-CoV-2 lineages are more efficient antagonists of innate immunity than their orthologs from SARS-CoV lineages. Mutational analyses identified residues E46 and Q56 as important determinants of the antagonistic activity of SARS-CoV-2 ORF6. Moreover, we show that the anti-innate immune activity of ORF6 depends on its C-terminal region and that ORF6 inhibits nuclear translocation of IRF3. Finally, we identify naturally occurring frameshift/nonsense mutations that result in an inactivating truncation of ORF6 in approximately 0.2% of SARS-CoV-2 isolates. Our findings suggest that ORF6 contributes to the poor IFN activation observed in individuals with coronavirus disease 2019 (COVID-19).

51 CT Head and Cervical Spine Audit in Patients Over the Age of 65: A District General Hospital Perspective

Introduction

Cervical spine (c-spine) injury has a high morbidity and mortality in patients over the age of 65; more than 60% result from falls from standing height (Beedham et al., 2019).

The Canadian Cervical Spine Rule (Stiell et al., 2001) deems that there is a high risk of c-spine fracture if any of the following apply:

The c-spine cannot be cleared clinically if the patient fits any of the above criteria. Imaging should be considered. As a result of recent clinical experiences Trust Guidelines at Stoke Mandeville Hospital now reflect this evidence (Hadley et al., 2019).

Methods

Fifty patients over the age of 65 who had a computerised tomography (CT) head scan in the Emergency Department (ED) following a traumatic head injury were randomly selected over a 1 month period. Cases were checked for examination of c-spine and/or CT c-spine. Results of the first cycle of the audit were presented at an ED Education Meeting. Indications for CT c-spine were displayed in poster format around the ED. Following these interventions, a re-audit was carried out using the same methodology.

Results

In fifty patients aged over 65 attending ED during one month, 16% had a CT c-spine in addition to a CT head. There was documented c-spine examination of 16% of those without CT c-spine on admission. In the re-audit 38% of the fifty patients who had a CT head underwent CT c-spine. In the group that did not have imaging of the c-spine, the proportion with documented cervical spine examination on admission remained the same (16%).

Conclusion

There was a 137.5% increase in the number of patients aged over 65 who appropriately underwent a CT c-spine as per Trust and National guidelines. Simple interventions (staff education and posters within the ED) were sufficient to significantly alter practice. Current trauma triage is not optimal for older patients who are reviewed by more junior doctors, less likely to be transferred to Major Trauma Centres and more likely to die than younger patients with similar injuries (Major Trauma In Older People 2017 Report). An older person’s trauma team in ED with age-appropriate triage would lead to appropriate imaging in a timely fashion, potentially improving the morbidity and mortality of these vulnerable patients.

Diagnosis of pleural empyema/parapneumonic effusion by next-generation sequencing

BACKGROUND

Although a microbiological diagnosis of pleural infection is clinically important, it is often complicated by prior antibiotic treatment and/or difficulties with culturing some bacterial species. Therefore, we aimed to identify probable causative bacteria in pleural empyema/parapneumonic effusions by combining 16S ribosomal RNA (rRNA) gene amplification and next-generation sequencing (NGS).

METHODS

Pleural fluids were collected from 19 patients with infectious effusions and nine patients with non-infectious malignant effusions. We analysed DNA extracted from the pleural fluid supernatant by NGS using the Genome Search Toolkit and GenomeSync database, either directly or after PCR amplification of the 16S rRNA gene. Infectious and non-infectious effusions were distinguished by semi-quantitative PCR of the 16S rRNA gene.

RESULTS

Only 8 (42%) effusions were culture-positive, however, NGS of the 16S rRNA gene amplicon identified 14 anaerobes and 7 aerobes/facultative anaerobes in all patients, including Streptococcus sp. (n = 6), Fusobacterium sp. (n = 5), Porphyromonas sp. (n = 5), and Prevotella sp. (n = 4), accounting for >10% of the total genomes. The culture and NGS results were discordant for 3 out of 8 patients, all of whom had previously been treated with antibiotics. Total (2^ΔCT value in semi-quantitative PCR of the 16S rRNA gene) and specific (total bacterial load multiplied by the proportion of primary bacteria in NGS) bacterial loads could efficiently distinguish empyema/parapneumonic effusion from non-infectious effusion.

CONCLUSION

Combining NGS with semi-quantitative PCR can facilitate the diagnosis of pleural empyema/parapneumonic effusion and its causal bacteria.

Nanopore direct RNA sequencing detects DUX4-activated repeats and isoforms in human muscle cells

Facioscapulohumeral muscular dystrophy (FSHD) is an inherited muscle disease caused by misexpression of the DUX4 gene in skeletal muscle. DUX4 is a transcription factor, which is normally expressed in the cleavage-stage embryo and regulates gene expression involved in early embryonic development. Recent studies revealed that DUX4 also activates the transcription of repetitive elements such as endogenous retroviruses (ERVs), mammalian apparent long terminal repeat (LTR)-retrotransposons and pericentromeric satellite repeats (Human Satellite II). DUX4-bound ERV sequences also create alternative promoters for genes or long non-coding RNAs, producing fusion transcripts. To further understand transcriptional regulation by DUX4, we performed nanopore long-read direct RNA sequencing (dRNA-seq) of human muscle cells induced by DUX4, because long reads show whole isoforms with greater confidence. We successfully detected differential expression of known DUX4-induced genes and discovered 61 differentially expressed repeat loci, which are near DUX4–ChIP peaks. We also identified 247 gene–ERV fusion transcripts, of which 216 were not reported previously. In addition, long-read dRNA-seq clearly shows that RNA splicing is a common event in DUX4-activated ERV transcripts. Long-read analysis showed non-LTR transposons including Alu elements are also transcribed from LTRs. Our findings revealed further complexity of DUX4-induced ERV transcripts. This catalogue of DUX4-activated repetitive elements may provide useful information to elucidate the pathology of FSHD. Also, our results indicate that nanopore dRNA-seq has complementary strengths to conventional short-read complementary DNA sequencing.

TRIM28 Expression on Dendritic Cells Prevents Excessive T Cell Priming by Silencing Endogenous Retrovirus

Acquired immune reaction is initiated by dendritic cells (DCs), which present Ags to a few naive Ag-specific T cells. Deregulation of gene expression in DCs may alter the outcome of the immune response toward immunodeficiency and/or autoimmune diseases. Expression of TRIM28, a nuclear protein that mediates gene silencing through heterochromatin, decreased in DCs from old mice, suggesting alteration of gene regulation. Mice specifically lacking TRIM28 in DCs show increased DC population in the spleen and enhanced T cell priming toward inflammatory effector T cells, leading to acceleration and exacerbation in experimental autoimmune encephalomyelitis. TRIM28-deficient DCs were found to ectopically transcribe endogenous retrovirus (ERV) elements. Combined genome-wide analysis revealed a strong colocalization among the decreased repressive histone mark H3K9me3-transcribed ERV elements and the derepressed host genes that were related to inflammation in TRIM28-deficient DCs. This suggests that TRIM28 occupancy of ERV elements critically represses expression of proximal inflammatory genes on the genome. We propose that gene silencing through repressive histone modification by TRIM28 plays a role in maintaining the integrity of precise gene regulation in DCs, which prevents aberrant T cell priming to inflammatory effector T cells.

Rapid profiling of drug-resistant bacteria using DNA-binding dyes and a nanopore-based DNA sequencer

Spread of drug-resistant bacteria is a serious problem worldwide. We thus designed a new sequence-based protocol that can quickly identify bacterial compositions of clinical samples and their drug-resistance profiles simultaneously. Here we utilized propidium monoazide (PMA) that prohibits DNA amplifications from dead bacteria, and subjected the original and antibiotics-treated samples to 16S rRNA metagenome sequencing. We tested our protocol on bacterial mixtures, and observed that sequencing reads derived from drug-resistant bacteria were significantly increased compared with those from drug-sensitive bacteria when samples were treated by antibiotics. Our protocol is scalable and will be useful for quickly profiling drug-resistant bacteria.

Full-length 16S rRNA gene amplicon analysis of human gut microbiota using MinION™ nanopore sequencing confers species-level resolution

Background

Species-level genetic characterization of complex bacterial communities has important clinical applications in both diagnosis and treatment. Amplicon sequencing of the 16S ribosomal RNA (rRNA) gene has proven to be a powerful strategy for the taxonomic classification of bacteria. This study aims to improve the method for full-length 16S rRNA gene analysis using the nanopore long-read sequencer MinION™. We compared it to the conventional short-read sequencing method in both a mock bacterial community and human fecal samples.

Results

We modified our existing protocol for full-length 16S rRNA gene amplicon sequencing by MinION™. A new strategy for library construction with an optimized primer set overcame PCR-associated bias and enabled taxonomic classification across a broad range of bacterial species. We compared the performance of full-length and short-read 16S rRNA gene amplicon sequencing for the characterization of human gut microbiota with a complex bacterial composition. The relative abundance of dominant bacterial genera was highly similar between full-length and short-read sequencing. At the species level, MinION™ long-read sequencing had better resolution for discriminating between members of particular taxa such as Bifidobacterium, allowing an accurate representation of the sample bacterial composition.

Conclusions

Our present microbiome study, comparing the discriminatory power of full-length and short-read sequencing, clearly illustrated the analytical advantage of sequencing the full-length 16S rRNA gene.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02094-5.