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Methicillin-resistant Staphylococcus aureus (MRSA) is an important human pathogen, which is cross-resistant to virtually all β-lactam antibiotics. MRSA strains are defined by the presence of mecA gene. The transcription of mecA can be regulated by a sensor-inducer (MecR1) and a repressor (MecI), involving a unique series of proteolytic steps. The induction of mecA by MecR1 has been described as very inefficient and, as such, it is believed that optimal expression of β-lactam resistance by MRSA requires a non-functional MecR1-MecI system. However, in a recent study, no correlation was found between the presence of functional MecR1-MecI and the level of β-lactam resistance in a representative collection of epidemic MRSA strains. Here, we demonstrate that the mecA regulatory locus consists, in fact, of an unusual three-component arrangement containing, in addition to mecR1-mecI, the up to now unrecognized mecR2 gene coding for an anti-repressor. The MecR2 function is essential for the full induction of mecA expression, compensating for the inefficient induction of mecA by MecR1 and enabling optimal expression of β-lactam resistance in MRSA strains with functional mecR1-mecI regulatory genes. Our data shows that MecR2 interacts directly with MecI, destabilizing its binding to the mecA promoter, which results in the repressor inactivation by proteolytic cleavage, presumably mediated by native cytoplasmatic proteases. These observations point to a revision of the current model for the transcriptional control of mecA and open new avenues for the design of alternative therapeutic strategies for the treatment of MRSA infections. Moreover, these findings also provide important insights into the complex evolutionary pathways of antibiotic resistance and molecular mechanisms of transcriptional regulation in bacteria.

Abstract Inherited retinal dystrophies/degenerations (IRDs) are the leading cause of visual impairment and incurable familial blindness in the Western world. Given the clinical and genetic heterogeneity, establishing a molecular diagnosis is especially relevant. The aim of this study was to perform the first nationwide survey to understand the prevalence and current management of IRDs in Portugal. A response was obtained from 26 healthcare providers (HCP) (76.5% response rate). Only 4 respondents reported not managing IRD patients. Most HCPs (68.1%) reported managing up to 100 patients, while three currently manage between 501 and 1000 patients. Based on the Portuguese population, an estimated IRD prevalence of 0.031%, i.e., about 1 in 3000 individuals, was calculated. In most HCPs (86.3%), most patients are adults, and non-syndromic retinitis pigmentosa is the most frequent diagnosis. Only 4 HCPs currently use the national, web-based IRD registry (IRD-PT). However, all but one respondent expressed interest in participating in such a registry. Genetic testing is available in 54.5%, with 58.3% HCPs reporting solved rates between 61–80%, but 4 to 9 months to get a genetic test result in 83.4% of cases. Based on this survey, the prevalence of biallelic RPE65-associated disease in Portugal is 0.00031%, i.e., approximately 1:300,000 individuals. Data from this study provide vital background information on national differences in the diagnosis and management of IRD patients. Nationwide implementation of the IRD-PT registry should be encouraged and supported to provide population-based reference data and to identify patients eligible for current and future therapies.

Abstract Background Inherited retinal diseases (IRDs) are a group of rare degenerative disorders of the retina that can lead to blindness from birth to late middle age. Knowing the target population and its resources is essential to better plan support measures. The aim of this study was to evaluate the socioeconomic characteristics of regions in Portugal where IRD patients reside to inform the planning of vision aid and rehabilitation intervention measures. Results This study included 1082 patients from 973 families, aged 3 to 92 years, with a mean age of 44.8 ± 18.1 years. Patients living with an IRD were identified in 190 of the 308 municipalities. According to this study, the estimated IRD prevalence in Portugal was 10.4 per 100,000 inhabitants, and by municipalities, it ranged from 0 to 131.2 per 100,000 inhabitants. Overall, regions with a higher prevalence of IRD have a lower population density (r=-0.371, p

ABSTRACT Objective: Age-related macular degeneration (AMD) is the most prevalent cause of irreversible visual loss in the developed world. In late stages, it may lead to extremely low visual acuities, especially when associated with geographic atrophy or choroidal neovascularization. According to recent literature, Charles Bonnet syndrome (CBS) may be a rather common feature of late AMD. Methods: One hundred patients with late-stage age-related macular degeneration were actively asked whether they had symptoms of Charles Bonnet syndrome. Those that answered positively underwent a comprehensive questionnaire about the details of the visual hallucinations. Results: The following factors were significantly associated with Charles Bonnet syndrome: older age (+6.3 years; p=0.003), lower visual acuity in the better eye (Charles Bonnet Syndrome Group: 0.11; Non-Charles Bonnet Syndrome Group: 0.42; p=0.005) and female sex (Charles Bonnet Syndrome Group: 88%; Non-Charles Bonnet Syndrome Group: 43%; p=0.02). The visual hallucinations occurred mainly straight ahead (n=5), once per day (n=4), at no particular time (n=6), lasted some minutes (n=5), and disappeared after blinking (n=3) or looking away (n=3). The majority of patients lived alone (n=7), had not told anyone about the hallucinations (n=6), and associated the episodes with severe distress (n=5). Conclusion: Charles Bonnet syndrome was fairly prevalent in this late-stage age-related macular degeneration population. Our sample shows the importance of directly asking subjects about Charles Bonnet syndrome since they are often reluctant to admit to having visual hallucinations. Reassurance about its benignity is crucial to improve their quality of life.

Regulatory small RNA (sRNA) interact with mRNAs to regulate their stability, transcription, and translation via diverse mechanisms. Here, McKellar et al. apply RNase IIICLASH of multi-drug resistant Staphylococcus aureus under different culture conditions to link the network of RNA-RNA interactions to environmental conditions and find that the production of small membrane-permeabilizing toxins is strongly regulated by sRNAs.

RNA-binding proteins play key roles in controlling gene expression in many organisms. Here, Chu et al. identify hundreds of RNA-binding proteins in methicillin-resistant Staphylococcus aureus, and show that a major transcription factor uses its helix-turn-helix domain to bind RNAs near intrinsic transcription terminators.

A large fraction of plant genomes is composed of transposable elements (TE), which provide a potential source of novel genes through "domestication"-the process whereby the proteins encoded by TE diverge in sequence, lose their ability to catalyse transposition and instead acquire novel functions for their hosts. In Arabidopsis, ANTAGONIST OF LIKE HETEROCHROMATIN PROTEIN 1 (ALP1) arose by domestication of the nuclease component of Harbinger class TE and acquired a new function as a component of POLYCOMB REPRESSIVE COMPLEX 2 (PRC2), a histone H3K27me3 methyltransferase involved in regulation of host genes and in some cases TE. It was not clear how ALP1 associated with PRC2, nor what the functional consequence was. Here, we identify ALP2 genetically as a suppressor of Polycomb-group (PcG) mutant phenotypes and show that it arose from the second, DNA binding component of Harbinger transposases. Molecular analysis of PcG compromised backgrounds reveals that ALP genes oppose silencing and H3K27me3 deposition at key PcG target genes. Proteomic analysis reveals that ALP1 and ALP2 are components of a variant PRC2 complex that contains the four core components but lacks plant-specific accessory components such as the H3K27me3 reader LIKE HETEROCHROMATION PROTEIN 1 (LHP1). We show that the N-terminus of ALP2 interacts directly with ALP1, whereas the C-terminus of ALP2 interacts with MULTICOPY SUPPRESSOR OF IRA1 (MSI1), a core component of PRC2. Proteomic analysis reveals that in alp2 mutant backgrounds ALP1 protein no longer associates with PRC2, consistent with a role for ALP2 in recruitment of ALP1. We suggest that the propensity of Harbinger TE to insert in gene-rich regions of the genome, together with the modular two component nature of their transposases, has predisposed them for domestication and incorporation into chromatin modifying complexes.

The aim of this work is to investigate the antibacterial effect of phenolic compound combinations and total polyphenols of Argentinean red wine varieties against Escherichia coli ATCC 35218 and Listeria monocytogenes using commercial fish meat as model food. Rutin-quercetin combination and three wine varieties (Cabernet Sauvignon, Malbec and Merlot) caused cellular death of both bacteria on fish meat at 4 °C. Rutin-quercetin combination was effective on fish meat even at 20 °C. Clarified wines did not affect the bacteria, indicating that wine polyphenols are responsible for the observed effect. The use of wine phenolic compounds as antibacterial agent could be used to prevent contamination and extend the shelf life of fish meat. A big finding of this work is the use of rutin–quercetin combination as preservative for the conservation of fish meat and its transport to the fish market, which is an effective antibacterial agent even when the transport temperature is not constant.