Polycomb Group-Dependent, Heterochromatin Protein 1-Independent, Chromatin Structures Silence Retrotransposons in Somatic Tissues Outside Ovaries

Somatic cells are equipped with different silencing mechanisms that protect the genome against retrotransposons. In Drosophila melanogaster, a silencing pathway implicating the argonaute protein PIWI represses retrotransposons in cells surrounding the oocyte, whereas a PIWI-independent pathway is involved in other somatic tissues. Here, we show that these two silencing mechanisms result in distinct chromatin structures. Using sensor transgenes, we found that, in somatic tissues outside of the ovaries, these transgenes adopt a heterochromatic configuration implicating hypermethylation of H3K9 and K27. We identified the Polycomb repressive complexes (PRC1 and 2), but not heterochromatin protein 1 to be necessary factors for silencing. Once established, the compact structure is stably maintained through cell divisions. By contrast, in cells where the silencing is PIWI-dependent, the transgenes display an open and labile chromatin structure. Our data suggest that a post-transcriptional gene silencing (PTGS) mechanism is responsible for the repression in the ovarian somatic cells, whereas a mechanism that couples PTGS to transcriptional gene silencing operates to silence retrotransposons in the other somatic tissues

A perspective on the measurement of time in plant disease epidemiology

The growth and development of plant pathogens and their hosts generally respond strongly to the temperature of their environment. However, most studies of plant pathology record pathogen/host measurements against physical time (e.g. hours or days) rather than thermal time (e.g. degree-days or degree-hours). This confounds the comparison of epidemiological measurements across experiments and limits the value of the scientific literature

The Epigenetic Trans-Silencing Effect in Drosophila Involves Maternally-Transmitted Small RNAs Whose Production Depends on the piRNA Pathway and HP1

BACKGROUND: The study of P transposable element repression in Drosophila melanogaster led to the discovery of the Trans-Silencing Effect (TSE), a homology-dependent repression mechanism by which a P-transgene inserted in subtelomeric heterochromatin (Telomeric Associated Sequences, "TAS") has the capacity to repress in trans, in the female germline, a homologous P-lacZ transgene located in euchromatin. Phenotypic and genetic analysis have shown that TSE exhibits variegation in ovaries, displays a maternal effect as well as epigenetic transmission through meiosis and involves heterochromatin (including HP1) and RNA silencing. PRINCIPAL FINDINGS: Here, we show that mutations in squash and zucchini, which are involved in the piwi-interacting RNA (piRNA) silencing pathway, strongly affect TSE. In addition, we carried out a molecular analysis of TSE and show that silencing is correlated to the accumulation of lacZ small RNAs in ovaries. Finally, we show that the production of these small RNAs is sensitive to mutations affecting squash and zucchini, as well as to the dose of HP1. CONCLUSIONS AND SIGNIFICANCE: Thus, our results indicate that the TSE represents a bona fide piRNA-based repression. In addition, the sensitivity of TSE to HP1 dose suggests that in Drosophila, as previously shown in Schizosaccharomyces pombe, a RNA silencing pathway can depend on heterochromatin components

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Recurrent complex incisional hernia repair by enhanced-view totally extraperitoneal (eTEP) technique.

Treatment of large recurrent abdominal wall hernias remains a surgical challenge. The enhanced-view totally extraperitoneal (eTEP) approach is an emerging technique used to treat hernias with minimally invasive procedure. This article illustrates a step-by-step eTEP approach, used in a complex recurrent hernia repair. A 56-years-old male had a previous epigastric hernia repair with an intraperitoneal onlay mesh (IPOM) technique in 2018. Six months later, he presented a recurrent epigastric protrusion and a new painful ombilical hernia, objectified on the CT-scan. Four suprapubic trocars were used to dissect the preperitoneal space below the arcuate line and the retromuscular spaces on both sides. On the mid-line, posterior fascia was divided and both hernia sacs were fully dissected. Both anterior and posterior sheats were closed with self-locking non-absorbable threads before placing a Polypropylene self-gripping mesh. The follow-up was uneventful, and the patient was discharged on day 2. This case report illustrates that eTEP technique can be used safely and effectively to treat complex recurrent ventral hernias even with a mesh already in place. The potential advantages of the eTEP procedure are multiple, such as improving mobility and esthetic results, reducing pain and shorting hospital length of stay

The Idefix enhancer-blocking insulator also harbors barrier activity

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