Terminal restriction fragment length polymorphism is an “old school” reliable technique for swift microbial community screening in anaerobic digestion

The microbial community in anaerobic digestion has been analysed through microbial fingerprinting techniques, such as terminal restriction fragment length polymorphism (TRFLP), for decades. In the last decade, high-throughput 16S rRNA gene amplicon sequencing has replaced these techniques, but the time-consuming and complex nature of high-throughput techniques is a potential bottleneck for full-scale anaerobic digestion application, when monitoring community dynamics. Here, the bacterial and archaeal TRFLP profiles were compared with 16S rRNA gene amplicon profiles (Illumina platform) of 25 full-scale anaerobic digestion plants. The α-diversity analysis revealed a higher richness based on Illumina data, compared with the TRFLP data. This coincided with a clear difference in community organisation, Pareto distribution, and co-occurrence network statistics, i.e., betweenness centrality and normalised degree. The β-diversity analysis showed a similar clustering profile for the Illumina, bacterial TRFLP and archaeal TRFLP data, based on different distance measures and independent of phylogenetic identification, with pH and temperature as the two key operational parameters determining microbial community composition. The combined knowledge of temporal dynamics and projected clustering in the β-diversity profile, based on the TRFLP data, distinctly showed that TRFLP is a reliable technique for swift microbial community dynamics screening in full-scale anaerobic digestion plants

A unified evolutionary origin for the ubiquitous protein transporters SecY and YidC.

BACKGROUND: Protein transporters translocate hydrophilic segments of polypeptide across hydrophobic cell membranes. Two protein transporters are ubiquitous and date back to the last universal common ancestor: SecY and YidC. SecY consists of two pseudosymmetric halves, which together form a membrane-spanning protein-conducting channel. YidC is an asymmetric molecule with a protein-conducting hydrophilic groove that partially spans the membrane. Although both transporters mediate insertion of membrane proteins with short translocated domains, only SecY transports secretory proteins and membrane proteins with long translocated domains. The evolutionary origins of these ancient and essential transporters are not known. RESULTS: The features conserved by the two halves of SecY indicate that their common ancestor was an antiparallel homodimeric channel. Structural searches with SecY's halves detect exceptional similarity with YidC homologs. The SecY halves and YidC share a fold comprising a three-helix bundle interrupted by a helical hairpin. In YidC, this hairpin is cytoplasmic and facilitates substrate delivery, whereas in SecY, it is transmembrane and forms the substrate-binding lateral gate helices. In both transporters, the three-helix bundle forms a protein-conducting hydrophilic groove delimited by a conserved hydrophobic residue. Based on these similarities, we propose that SecY originated as a YidC homolog which formed a channel by juxtaposing two hydrophilic grooves in an antiparallel homodimer. We find that archaeal YidC and its eukaryotic descendants use this same dimerisation interface to heterodimerise with a conserved partner. YidC's sufficiency for the function of simple cells is suggested by the results of reductive evolution in mitochondria and plastids, which tend to retain SecY only if they require translocation of large hydrophilic domains. CONCLUSIONS: SecY and YidC share previously unrecognised similarities in sequence, structure, mechanism, and function. Our delineation of a detailed correspondence between these two essential and ancient transporters enables a deeper mechanistic understanding of how each functions. Furthermore, key differences between them help explain how SecY performs its distinctive function in the recognition and translocation of secretory proteins. The unified theory presented here explains the evolution of these features, and thus reconstructs a key step in the origin of cells

Terminal restriction fragment length polymorphism is an “old school” reliable technique for swift microbial community screening in anaerobic digestion

The microbial community in anaerobic digestion has been analysed through microbial fingerprinting techniques, such as terminal restriction fragment length polymorphism (TRFLP), for decades. In the last decade, high-throughput 16S rRNA gene amplicon sequencing has replaced these techniques, but the time-consuming and complex nature of high-throughput techniques is a potential bottleneck for full-scale anaerobic digestion application, when monitoring community dynamics. Here, the bacterial and archaeal TRFLP profiles were compared with 16S rRNA gene amplicon profiles (Illumina platform) of 25 full-scale anaerobic digestion plants. The α-diversity analysis revealed a higher richness based on Illumina data, compared with the TRFLP data. This coincided with a clear difference in community organisation, Pareto distribution, and co-occurrence network statistics, i.e., betweenness centrality and normalised degree. The β-diversity analysis showed a similar clustering profile for the Illumina, bacterial TRFLP and archaeal TRFLP data, based on different distance measures and independent of phylogenetic identification, with pH and temperature as the two key operational parameters determining microbial community composition. The combined knowledge of temporal dynamics and projected clustering in the β-diversity profile, based on the TRFLP data, distinctly showed that TRFLP is a reliable technique for swift microbial community dynamics screening in full-scale anaerobic digestion plants. © 2018, The Author(s)

Systemic treatments for psoriasis: not another network meta?analysis!

Linked Article: Guelimi et al. Br J Dermatol 2022; 187:29–41

Decentralized formation pose estimation for spacecraft swarms

For spacecraft swarms, the multi-agent localization algorithm must scale well with the number of spacecraft and adapt to time-varying communication and relative sensing networks. In this paper, we present a decentralized, scalable algorithm for swarm localization, called the Decentralized Pose Estimation (DPE) algorithm. The DPE considers both communication and relative sensing graphs and defines an observable local formation. Each spacecraft jointly localizes its local subset of spacecraft using direct and communicated measurements. Since the algorithm is local, the algorithm complexity does not grow with the number of spacecraft in the swarm. As part of the DPE, we present the Swarm Reference Frame Estimation (SRFE) algorithm, a distributed consensus algorithm to co-estimate a common Local-Vertical, Local-Horizontal (LVLH) frame. The DPE combined with the SRFE provides a scalable, fully-decentralized navigation solution that can be used for swarm control and motion planning. Numerical simulations and experiments using Caltech’s robotic spacecraft simulators are presented to validate the effectiveness and scalability of the DPE algorithm

Decentralized Formation Pose Estimation for Spacecraft Swarms

For spacecraft swarms, the multi-agent localization algorithm must scale well with the number of spacecraft and adapt to time-varying communication and relative sensing networks. In this paper, we present a decentralized, scalable algorithm for swarm localization, called the Decentralized Pose Estimation (DPE) algorithm. The DPE considers both communication and relative sensing graphs and defines an observable local formation. Each spacecraft jointly localizes its local subset of spacecraft using direct and communicated measurements. Since the algorithm is local, the algorithm complexity does not grow with the number of spacecraft in the swarm. As part of the DPE, we present the Swarm Reference Frame Estimation (SRFE) algorithm, a distributed consensus algorithm to co-estimate a common Local-Vertical, Local-Horizontal (LVLH) frame. The DPE combined with the SRFE provides a scalable, fully-decentralized navigation solution that can be used for swarm control and motion planning. Numerical simulations and experiments using Caltech’s robotic spacecraft simulators are presented to validate the effectiveness and scalability of the DPE algorithm

Topical tetracaine prior to arterial puncture: a randomized, placebo-controlled clinical trial

AbstractThe objective of this randomized, double-blind, placebo-controlled clinical trial was to determine whether a topical anesthetic agent (tetracaine) provides effective local analgesia prior to radial arterial puncture. Tetracaine or placebo gel was applied 45min prior to arterial puncture to patients who were referred for elective arterial blood gas. The primary outcome was the patient's perception of pain associated with the procedure as measured by a visual analog scale. Fifty patients were randomized into the study, 24 received tetracaine and 26 placebo. Mean pain score on the visual analog scale was 26.2±32.6 for the tetracaine-treated patients and 23.8±27.4 for the placebo-treated patients (P=0.78). Mean time from the first skin puncture to successful procurement of 1ml of arterial blood was 70±103s in the tetracaine group and 49±48s in the placebo group (P=0.40). Difficulty of arterial puncture as assessed by the respiratory therapist performing the test was identical for the two groups (P=0.86). We conclude that tetracaine gel did not decrease patient's perception of pain associated with arterial puncture, nor did its use facilitate the ABG procedure

Running a paediatric ambulatory sleep service in a pandemic and beyond

OBJECTIVES: In response COVID-19, re-establishing safe elective services was prioritised in the UK. We assess the impact on face-to-face hospital attendance, cost, and efficiency of implementing a virtual sleep clinic (intervention 1) to screen for children requiring level 3 ambulatory sleep studies using newly implemented ENT-UK guidelines for obstructive sleep apnoea (OSA) investigation (intervention 2). OBJECTIVES: (1) compare the proportion of children attending sleep clinic undertaking a sleep study before and after implementation of these interventions; (2) compare clinic cancellations and first-time success rates of sleep studies before and after intervention. DESIGN: Retrospective analysis. SETTING: District general hospital paediatric sleep clinic. PARTICIPANTS: Children aged 3 months to 16 years referred to sleep clinic by ENT for investigation of OSA over the 3-months immediately following interventions (1 June 2020 - 1 September 2020) to the same period in the previous year (1 June 2019 - 1 September 2019). MAIN OUTCOME MEASURES: Number of children attending sleep clinic; date of birth / age of children attending sleep clinic; of number of children undergoing sleep study; diagnostic outcomes; number of appointment cancellations; number of first-time sleep study failures. RESULTS: Post-intervention, there was a significant reduction in the proportion of children undertaking ambulatory sleep studies, and non-significant reductions in appointment cancellations and in first-time sleep study failures. CONCLUSIONS: The introduction of the virtual sleep clinic meant that only those children requiring a sleep study attended a face-to-face appointment, which led to reduced face-to-face attendance. There were also unintended cost-effectiveness and efficiency benefits, with potential longer-term learning implications for the wider sleep community and other diagnostic services