Interactions between U and V sex chromosomes during the life cycle of Ectocarpus.

In many animals and flowering plants, sex determination occurs in the diploid phase of the life cycle with XX/XY or ZW/ZZ sex chromosomes. However, in early diverging plants and most macroalgae, sex is determined by female (U) or male (V) sex chromosomes in a haploid phase called the gametophyte. Once the U and V chromosomes unite at fertilization to produce a diploid sporophyte, sex determination no longer occurs, raising key questions about the fate of the U and V sex chromosomes in the sporophyte phase. Here, we investigate genetic and molecular interactions of the UV sex chromosomes in both the haploid and diploid phases of the brown alga Ectocarpus. We reveal extensive developmental regulation of sex chromosome genes across its life cycle and implicate the TALE-HD transcription factor OUROBOROS in suppressing sex determination in the diploid phase. Small RNAs may also play a role in the repression of a female sex-linked gene, and transition to the diploid sporophyte coincides with major reconfiguration of histone H3K79me2, suggesting a more intricate role for this histone mark in Ectocarpus development than previously appreciated.

Cell cycle status of male and female gametes during Arabidopsis reproduction.

Fertilization in Arabidopsis (Arabidopsis thaliana) is a highly coordinated process that begins with a pollen tube delivering the 2 sperm cells into the embryo sac. Each sperm cell can then fertilize either the egg or the central cell to initiate embryo or endosperm development, respectively. The success of this double fertilization process requires a tight cell cycle synchrony between the male and female gametes to allow karyogamy (nuclei fusion). However, the cell cycle status of the male and female gametes during fertilization remains elusive as DNA quantification and DNA replication assays have given conflicting results. Here, to reconcile these results, we quantified the DNA replication state by DNA sequencing and performed microscopic analyses of fluorescent markers covering all phases of the cell cycle. We show that male and female Arabidopsis gametes are both arrested prior to DNA replication at maturity and initiate their DNA replication only during fertilization.

Chromatin landscape associated with sexual differentiation in a UV sex determination system.

In many eukaryotes, such as dioicous mosses and many algae, sex is determined by UV sex chromosomes and is expressed during the haploid phase of the life cycle. In these species, the male and female developmental programs are initiated by the presence of the U- or V-specific regions of the sex chromosomes but, as in XY and ZW systems, sexual differentiation is largely driven by autosomal sex-biased gene expression. The mechanisms underlying the regulation of sex-biased expression of genes during sexual differentiation remain elusive. Here, we investigated the extent and nature of epigenomic changes associated with UV sexual differentiation in the brown alga Ectocarpus, a model UV system. Six histone modifications were quantified in near-isogenic lines, leading to the identification of 16 chromatin signatures across the genome. Chromatin signatures correlated with levels of gene expression and histone PTMs changes in males versus females occurred preferentially at genes involved in sex-specific pathways. Despite the absence of chromosome scale dosage compensation and the fact that UV sex chromosomes recombine across most of their length, the chromatin landscape of these chromosomes was remarkably different to that of autosomes. Hotspots of evolutionary young genes in the pseudoautosomal regions appear to drive the exceptional chromatin features of UV sex chromosomes.

The atypical histone variant H3.15 promotes callus formation in Arabidopsis thaliana.

Plants are capable of regenerating new organs after mechanical injury. The regeneration process involves genome-wide reprogramming of transcription, which usually requires dynamic changes in the chromatin landscape. We show that the histone 3 variant HISTONE THREE RELATED 15 (H3.15) plays an important role in cell fate reprogramming during plant regeneration in Arabidopsis H3.15 expression is rapidly induced upon wounding. Ectopic overexpression of H3.15 promotes cell proliferation to form a larger callus at the wound site, whereas htr15 mutation compromises callus formation. H3.15 is distinguished from other Arabidopsis histones by the absence of the lysine residue 27 that is trimethylated by the POLYCOMB REPRESSIVE COMPLEX 2 (PRC2) in constitutively expressed H3 variants. Overexpression of H3.15 promotes the removal of the transcriptional repressive mark H3K27me3 from chromatin, which results in transcriptional de-repression of downstream genes, such as WUSCHEL RELATED HOMEOBOX 11 (WOX11). Our results reveal a new mechanism for a release from PRC2-mediated gene repression through H3.15 deposition into chromatin, which is involved in reprogramming cell fate to produce pluripotent callus cells.

Red macroalgae in the genomic era.

Rhodophyta (or red algae) are a diverse and species-rich group that forms one of three major lineages in the Archaeplastida, a eukaryotic supergroup whose plastids arose from a single primary endosymbiosis. Red algae are united by several features, such as relatively small intron-poor genomes and a lack of cytoskeletal structures associated with motility like flagella and centrioles, as well as a highly efficient photosynthetic capacity. Multicellular red algae (or macroalgae) are one of the earliest diverging eukaryotic lineages to have evolved complex multicellularity, yet despite their ecological, evolutionary, and commercial importance, they have remained a largely understudied group of organisms. Considering the increasing availability of red algal genome sequences, we present a broad overview of fundamental aspects of red macroalgal biology and posit on how this is expected to accelerate research in many domains of red algal biology in the coming years.

The evolution and functional divergence of the histone H2B family in plants.

Chromatin regulation of eukaryotic genomes depends on the formation of nucleosome complexes between histone proteins and DNA. Histone variants, which are diversified by sequence or expression pattern, can profoundly alter chromatin properties. While variants in histone H2A and H3 families are well characterized, the extent of diversification of histone H2B proteins is less understood. Here, we report a systematic analysis of the histone H2B family in plants, which have undergone substantial divergence during the evolution of each major group in the plant kingdom. By characterising Arabidopsis H2Bs, we substantiate this diversification and reveal potential functional specialization that parallels the phylogenetic structure of emergent clades in eudicots. In addition, we identify a new class of highly divergent H2B variants, H2B.S, that specifically accumulate during chromatin compaction of dry seed embryos in multiple species of flowering plants. Our findings thus identify unsuspected diverse properties among histone H2B proteins in plants that has manifested into potentially novel groups of histone variants.

Revisiting the personal protective equipment components of transmission-based precautions for the prevention of COVID-19 and other respiratory virus infections in healthcare.

The COVID-19 pandemic highlighted some potential limitations of transmission-based precautions. The distinction between transmission through large droplets vs aerosols, which have been fundamental concepts guiding infection control measures, has been questioned, leading to considerable variation in expert recommendations on transmission-based precautions for COVID-19. Furthermore, the application of elements of contact precautions, such as the use of gloves and gowns, is based on low-quality and inconclusive evidence and may have unintended consequences, such as increased incidence of healthcare-associated infections and spread of multidrug-resistant organisms. These observations indicate a need for high-quality studies to address the knowledge gaps and a need to revisit the theoretical background regarding various modes of transmission and the definitions of terms related to transmission. Further, we should examine the implications these definitions have on the following components of transmission-based precautions: (i) respiratory protection, (ii) use of gloves and gowns for the prevention of respiratory virus infections, (iii) aerosol-generating procedures and (iv) universal masking in healthcare settings as a control measure especially during seasonal epidemics. Such a review would ensure that transmission-based precautions are consistent and rationally based on available evidence, which would facilitate decision-making, guidance development and training, as well as their application in practice.

Ustilago maydis effector Jsi1 interacts with Topless corepressor, hijacking plant jasmonate/ethylene signaling.

Ustilago maydis is the causal agent of maize smut disease. During the colonization process, the fungus secretes effector proteins that suppress immune responses and redirect the host metabolism in favor of the pathogen. As effectors play a critical role during plant colonization, their identification and functional characterization are essential to understanding biotrophy and disease. Using biochemical, molecular, and transcriptomic techniques, we performed a functional characterization of the U. maydis effector Jasmonate/Ethylene signaling inducer 1 (Jsi1). Jsi1 interacts with several members of the plant corepressor family Topless/Topless related (TPL/TPR). Jsi1 expression in Zea mays and Arabidopsis thaliana leads to transcriptional induction of the ethylene response factor (ERF) branch of the jasmonate/ethylene (JA/ET) signaling pathway. In A. thaliana, activation of the ERF branch leads to biotrophic susceptibility. Jsi1 likely activates the ERF branch via an EAR (ET-responsive element binding-factor-associated amphiphilic repression) motif, which resembles EAR motifs from plant ERF transcription factors, that interacts with TPL/TPR proteins. EAR-motif-containing effector candidates were identified from different fungal species, including Magnaporthe oryzae, Sporisorium scitamineum, and Sporisorium reilianum. Interaction between plant TPL proteins and these effector candidates from biotrophic and hemibiotrophic fungi indicates the convergent evolution of effectors modulating the TPL/TPR corepressor hub.

Adverse reactions to Pfizer-BioNTech vaccination of healthcare workers at Malta's state hospital.

BACKGROUND: The long-term control of COVID-19 depends on an effective global vaccination strategy. Protecting healthcare workers (HCWs) from serious infection is critical. Malta, a European country, initiated the vaccination roll-out using Pfizer-BioNTech COVID-19 vaccine targeting HCWs. This study determined vaccination adverse effects (AEs) in this cohort. METHOD: An online survey was disseminated to all HCWs via work email (29/3/21 to 9/4/21) to gather AEs regarding pain, redness and swelling at injection site, fever, chills, fatigue, muscle/joint pains, headache, vomiting and diarrhoea severity following each dose (Likert scale). Descriptive, comparative and multiple binary regression analyses were performed. RESULTS: A response of 30.30% (n = 1480) was achieved with the commonest AEs being pain at injection site (88.92% CI 95%: 87.21-90.42), mostly mild (51%) and moderate (43%). Fatigue was reported by 72.97% (CI 95%: 70.65-75.17), 42% were mild and 41% were moderate. Females reported significantly (P ≤ .05, respectively) more pain (OR: 1.90), redness (OR: 2.49), swelling at injection site (OR: 1.33), fever (OR: 1.74), chills (OR: 2.32), fatigue (OR: 2.43), muscle (OR: 1.54) and joint pains (OR: 2.01), headache (OR: 2.07) and vomiting (OR: 3.43) when adjusted for age and HCW role. Localised AEs were reported following both vaccine doses unlike systemic AEs that were mostly reported after second doses. CONCLUSION: Vaccination benefits outweigh the minor AEs experienced, with females exhibiting a higher susceptibility. The general low vaccination AEs observed within the HCW cohort is encouraging and should help in allaying vaccine hesitancy among the population.

Broad-spectrum antibiotic use in Europe: more evidence of cultural influences on prescribing behaviour.

OBJECTIVES: Sociocultural factors have been hypothesized as important drivers of inappropriate antibiotic prescribing in European ambulatory care. This study sought to assess whether they can also explain the reported variation in broad-spectrum antibiotic (Br-Ab) use among EU/European Economic Area (EEA) countries. METHODS: Correlation and regression analysis were performed, using the bootstrap method, between Br-Ab ratios reported from 28 EU countries by the ECDC, and national Hofstede cultural dimensions and control of corruption (CoC) scores. RESULTS: Significant bootstrapping correlation coefficients were identified between Br-Ab ratios and the dimension of uncertainty avoidance (UAI) as well as CoC. However, following both bootstrapping multiple regression and generalized linear modelling, only UAI was retained as the sole predictor. A logarithmic model explained 58.6% of the variation in European Br-Ab variability solely using national UAI scores (P < 0.001). CONCLUSIONS: Br-Ab prescribing appears to be driven by the level of UAI within the country. Any interventions aimed at reducing Br-Ab in high-consuming EU/EEA countries need to address this cultural perception to maximize their chances of success.

Antibiotic prescribing for respiratory tract complaints in Malta: a 1 year repeated cross-sectional surveillance study.

OBJECTIVES: To determine the 1 year antibiotic prescribing patterns by GPs for acute respiratory tract complaints (aRTCs) in Malta. METHODS: In this repeated cross-sectional surveillance study, GPs collected data for patients seen for aRTCs during a designated 1 week period each month, between May 2015 and April 2016. GPs received three text reminders during surveillance weeks and were contacted by phone at most four times during the year. GPs also received 3 monthly individual- and aggregate-level feedback reports on their antibiotic prescribing patterns. Descriptive statistics were used to examine patient, consultation and clinical characteristics, and to describe GPs' prescribing patterns. RESULTS: Participating GPs (n = 33) registered 4641 patients with an aRTC, of whom 2122 (45.7%) received an antibiotic prescription. The majority (99.6%) of antibiotics prescribed were broad-spectrum and the most commonly prescribed antibiotics were macrolides (35.5%), followed by penicillins with a ß-lactamase inhibitor (33.2%) and second-generation cephalosporins (14.2%). Specifically, co-amoxiclav (33.2%), clarithromycin (19.6%), azithromycin (15.1%) and cefuroxime axetil (10.9%) represented 78.8% of all antibiotics prescribed. Patients with tonsillar exudate (99.1%), purulent sputum (84%), otorrhoea (78%), tender cervical nodes (74.4%) and fever (73.1%) received most antibiotics. The diagnoses that received the highest proportion of antibiotic treatment were tonsillitis (96.3%), otitis media (92.5%) and bronchitis (87.5%). Wide variation in the choice of antibiotic class by diagnosis was observed. CONCLUSIONS: GP antibiotic prescribing in Malta is high. The abundant use of broad-spectrum antibiotics, particularly macrolides, is of particular concern and indicates that antibiotics are being used inappropriately. Efforts must be made to improve GP awareness of appropriate antibiotic prescribing.

A Conserved cis-Regulatory Module Determines Germline Fate through Activation of the Transcription Factor DUO1 Promoter.

The development of the male germline within pollen relies upon the activation of numerous target genes by the transcription factor DUO POLLEN1 (DUO1). The expression of DUO1 is restricted to the male germline and is first detected shortly after the asymmetric division that segregates the germ cell lineage. Transcriptional regulation is critical in controlling DUO1 expression, since transcriptional and translational fusions show similar expression patterns. Here, we identify key promoter sequences required for the germline-specific regulation of DUO1 transcription. Combining promoter deletion analyses with phylogenetic footprinting in eudicots and in Arabidopsis accessions, we identify a cis-regulatory module, Regulatory region of DUO1 (ROD1), which replicates the expression pattern of DUO1 in Arabidopsis (Arabidopsis thaliana). We show that ROD1 from the legume Medicago truncatula directs male germline-specific expression in Arabidopsis, demonstrating conservation of DUO1 regulation among eudicots. ROD1 contains several short conserved cis-regulatory elements, including three copies of the motif DNGTGGV, required for germline expression and tandem repeats of the motif YAACYGY, which enhance DUO1 transcription in a positive feedback loop. We conclude that a cis-regulatory module conserved in eudicots directs the spatial and temporal expression of the transcription factor DUO1 to specify male germline fate and sperm cell differentiation.

An EAR-Dependent Regulatory Module Promotes Male Germ Cell Division and Sperm Fertility in Arabidopsis.

The production of the sperm cells in angiosperms requires coordination of cell division and cell differentiation. In Arabidopsis thaliana, the germline-specific MYB protein DUO1 integrates these processes, but the regulatory hierarchy in which DUO1 functions is unknown. Here, we identify an essential role for two germline-specific DUO1 target genes, DAZ1 and DAZ2, which encode EAR motif-containing C2H2-type zinc finger proteins. We show that DAZ1/DAZ2 are required for germ cell division and for the proper accumulation of mitotic cyclins. Importantly, DAZ1/DAZ2 are sufficient to promote G2- to M-phase transition and germ cell division in the absence of DUO1. DAZ1/DAZ2 are also required for DUO1-dependent cell differentiation and are essential for gamete fusion at fertilization. We demonstrate that the two EAR motifs in DAZ1/DAZ2 mediate their function in the male germline and are required for transcriptional repression and for physical interaction with the corepressor TOPLESS. Our findings uncover an essential module in a regulatory hierarchy that drives mitotic transition in male germ cells and implicates gene repression pathways in sperm cell formation and fertility.

Chromatin remodelling during male gametophyte development.

The plant life cycle alternates between a diploid sporophytic phase and haploid gametophytic phase, with the latter giving rise to the gametes. Male gametophyte development encompasses two mitotic divisions that results in a simple three-celled structure knows as the pollen grain, in which two sperm cells are encased within a larger vegetative cell. Both cell types exhibit a very different type of chromatin organization - highly condensed in sperm cell nuclei and highly diffuse in the vegetative cell. Distinct classes of histone variants have dynamic and differential expression in the two cell lineages of the male gametophyte. Here we review how the dynamics of histone variants are linked to reprogramming of chromatin activities in the male gametophyte, compaction of the sperm cell genome and zygotic transitions post-fertilization.

Prolonged perioperative surgical prophylaxis within European hospitals: an exercise in uncertainty avoidance?

OBJECTIVES: Socio-cultural factors have been hypothesized to be important drivers for inappropriate antibiotic prescribing in ambulatory care. This study sought to assess any potential role in perioperative surgical prophylaxis (PAP) administered for >24 h (PAP > 24). Within hospitals, PAP continues to be administered for longer than 24 h, despite unequivocal evidence of ineffectiveness beyond this period. A recently published European Centre for Disease Prevention and Control (ECDC) point prevalence survey (PPS) has reported that in 70% of participating countries, PAP > 24 was administered in more than half of the surgical operations surveyed. METHODS: Correlation and simple linear regression modelling was performed using the PAP > 24 proportions for the countries in the ECDC PPS report and the respective scores for the cultural construct of uncertainty avoidance (UA), as detailed by Hofstede. RESULTS: Pearson correlation analysis produced a moderately strong coefficient (r) of 0.50 (95% CI 0.16-0.74; P = 0.007). Simple regression yielded a model of PAP > 24 = 29.87 + 0.40UA (R(2) = 0.25; P = 0.007). CONCLUSIONS: Cultural factors, namely UA, appear to be an important driver for PAP > 24. Any strategy aimed at improving prolonged PAP should be informed by clear knowledge of local socio-cultural barriers, so as to achieve the most successful intervention possible.

The R2R3 MYB transcription factor DUO1 activates a male germline-specific regulon essential for sperm cell differentiation in Arabidopsis.

The male germline in flowering plants arises through asymmetric division of a haploid microspore. The resulting germ cell undergoes mitotic division and specialization to produce the two sperm cells required for double fertilization. The male germline-specific R2R3 MYB transcription factor DUO1 POLLEN1 (DUO1) plays an essential role in sperm cell specification by activating a germline-specific differentiation program. Here, we show that ectopic expression of DUO1 upregulates a significant number (~63) of germline-specific or enriched genes, including those required for fertilization. We validated 14 previously unknown DUO1 target genes by demonstrating DUO1-dependent promoter activity in the male germline. DUO1 is shown to directly regulate its target promoters through binding to canonical MYB sites, suggesting that the DUO1 target genes validated thus far are likely to be direct targets. This work advances knowledge of the DUO1 regulon that encompasses genes with a range of cellular functions, including transcription, protein fate, signaling, and transport. Thus, the DUO1 regulon has a major role in shaping the germline transcriptome and functions to commit progenitor germ cells to sperm cell differentiation.

The role and utilisation of public health evaluations in Europe: a case study of national hand hygiene campaigns.

BACKGROUND: Evaluations are essential to judge the success of public health programmes. In Europe, the proportion of public health programmes that undergo evaluation remains unclear. The European Centre for Disease Prevention and Control sought to determine the frequency of evaluations amongst European national public health programmes by using national hand hygiene campaigns as an example of intervention. METHODS: A cohort of all national hand hygiene campaigns initiated between 2000 and 2012 was utilised for the analysis. The aim was to collect information about evaluations of hand hygiene campaigns and their frequency. The survey was sent to nominated contact points for healthcare-associated infection surveillance in European Union and European Economic Area Member States. RESULTS: Thirty-six hand hygiene campaigns in 20 countries were performed between 2000 and 2012. Of these, 50% had undergone an evaluation and 55% of those utilised the WHO hand hygiene intervention self-assessment tool. Evaluations utilised a variety of methodologies and indicators in assessing changes in hand hygiene behaviours pre and post intervention. Of the 50% of campaigns that were not evaluated, two thirds reported that both human and financial resource constraints posed significant barriers for the evaluation. CONCLUSION: The study identified an upward trend in the number of hand hygiene campaigns implemented in Europe. It is likely that the availability of the internationally-accepted evaluation methodology developed by the WHO contributed to the evaluation of more hand hygiene campaigns in Europe. Despite this rise, hand hygiene campaigns appear to be under-evaluated. The development of simple, programme-specific, standardised guidelines, evaluation indicators and other evidence-based public health materials could help promote evaluations across all areas of public health.

Perceptions of organizational culture among infection preventionists in Israel, the United States, and Thailand: Results from national infection prevention surveys.

In national surveys of infection preventionists in Israel (n = 15), the United States (n = 415), and Thailand (n = 100), we found that views of organizational culture track well with these countries' cultural dimension scores of power distance and individualism. Our findings highlight the importance of considering cultural dimensions when implementing infection prevention efforts.

Charting a course for global progress in PIDs by 2030 - proceedings from the IPOPI global multi-stakeholders' summit (September 2023).

The International Patient Organisation for Primary Immunodeficiencies (IPOPI) held its second Global Multi-Stakeholders' Summit, an annual stimulating and forward-thinking meeting uniting experts to anticipate pivotal upcoming challenges and opportunities in the field of primary immunodeficiency (PID). The 2023 summit focused on three key identified discussion points: (i) How can immunoglobulin (Ig) therapy meet future personalized patient needs? (ii) Pandemic preparedness: what's next for public health and potential challenges for the PID community? (iii) Diagnosing PIDs in 2030: what needs to happen to diagnose better and to diagnose more? Clinician-Scientists, patient representatives and other stakeholders explored avenues to improve Ig therapy through mechanistic insights and tailored Ig preparations/products according to patient-specific needs and local exposure to infectious agents, amongst others. Urgency for pandemic preparedness was discussed, as was the threat of shortage of antibiotics and increasing antimicrobial resistance, emphasizing the need for representation of PID patients and other vulnerable populations throughout crisis and care management. Discussion also covered the complexities of PID diagnosis, addressing issues such as global diagnostic disparities, the integration of patient-reported outcome measures, and the potential of artificial intelligence to increase PID diagnosis rates and to enhance diagnostic precision. These proceedings outline the outcomes and recommendations arising from the 2023 IPOPI Global Multi-Stakeholders' Summit, offering valuable insights to inform future strategies in PID management and care. Integral to this initiative is its role in fostering collaborative efforts among stakeholders to prepare for the multiple challenges facing the global PID community.

Arabidopsis Fused kinase and the Kinesin-12 subfamily constitute a signalling module required for phragmoplast expansion.

The conserved Fused kinase plays vital but divergent roles in many organisms from Hedgehog signalling in Drosophila to polarization and chemotaxis in Dictyostelium. Previously we have shown that Arabidopsis Fused kinase termed TWO-IN-ONE (TIO) is essential for cytokinesis in both sporophytic and gametophytic cell types. Here using in vivo imaging of GFP-tagged microtubules in dividing microspores we show that TIO is required for expansion of the phragmoplast. We identify the phragmoplast-associated kinesins, PAKRP1/Kinesin-12A and PAKRP1L/Kinesin-12B, as TIO-interacting proteins and determine TIO-Kinesin-12 interaction domains and their requirement in male gametophytic cytokinesis. Our results support the role of TIO as a functional protein kinase that interacts with Kinesin-12 subfamily members mainly through the C-terminal ARM repeat domain, but with a contribution from the N-terminal kinase domain. The interaction of TIO with Kinesin proteins and the functional requirement of their interaction domains support the operation of a Fused kinase signalling module in phragmoplast expansion that depends upon conserved structural features in diverse Fused kinases.