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1.
Mol Cell ; 83(5): 746-758.e5, 2023 03 02.
Artículo en Inglés | MEDLINE | ID: mdl-36805026

RESUMEN

Type I CRISPR-Cas systems employ multi-subunit Cascade effector complexes to target foreign nucleic acids for destruction. Here, we present structures of D. vulgaris type I-C Cascade at various stages of double-stranded (ds)DNA target capture, revealing mechanisms that underpin PAM recognition and Cascade allosteric activation. We uncover an interesting mechanism of non-target strand (NTS) DNA stabilization via stacking interactions with the "belly" subunits, securing the NTS in place. This "molecular seatbelt" mechanism facilitates efficient R-loop formation and prevents dsDNA reannealing. Additionally, we provide structural insights into how two anti-CRISPR (Acr) proteins utilize distinct strategies to achieve a shared mechanism of type I-C Cascade inhibition by blocking PAM scanning. These observations form a structural basis for directional R-loop formation and reveal how different Acr proteins have converged upon common molecular mechanisms to efficiently shut down CRISPR immunity.


Asunto(s)
Proteínas Asociadas a CRISPR , Estructuras R-Loop , Conformación Proteica , Modelos Moleculares , ADN/genética , Sistemas CRISPR-Cas , Proteínas Asociadas a CRISPR/genética
2.
Trends Genet ; 39(10): 787-801, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37633768

RESUMEN

Environmental stressors caused by climate change are fundamental barriers to agricultural sustainability. Enhancing the stress resilience of crops is a key strategy in achieving global food security. Plants perceive adverse environmental conditions and initiate signaling pathways to activate precise responses that contribute to their survival. WRKY transcription factors (TFs) are essential players in several signaling cascades and regulatory networks that have crucial implications for defense responses in plants. This review summarizes advances in research concerning how WRKY TFs mediate various signaling cascades and metabolic adjustments as well as how epigenetic modifications involved in environmental stress responses in plants can modulate WRKYs and/or their downstream genes. Emerging research shows that clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas)-mediated genome editing of WRKYs could be used to improve crop resilience.


Asunto(s)
Productos Agrícolas , Factores de Transcripción , Factores de Transcripción/genética , Productos Agrícolas/genética , Epigénesis Genética , Edición Génica , Transducción de Señal/genética
3.
Development ; 149(19)2022 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-36189831

RESUMEN

Nephron endowment is defined by fetal kidney growth and crucially dictates renal health in adults. Defects in the molecular regulation of nephron progenitors contribute to only a fraction of reduced nephron mass cases, suggesting alternative causative mechanisms. The importance of MAPK/ERK activation in nephron progenitor maintenance has been previously demonstrated, and here, we characterized the metabolic consequences of MAPK/ERK deficiency. Liquid chromatography/mass spectrometry-based metabolomics profiling identified 42 reduced metabolites, of which 26 were supported by in vivo transcriptional changes in MAPK/ERK-deficient nephron progenitors. Among these, mitochondria, ribosome and amino acid metabolism, together with diminished pyruvate and proline metabolism, were the most affected pathways. In vitro cultures of mouse kidneys demonstrated a dosage-specific function for pyruvate in controlling the shape of the ureteric bud tip, a regulatory niche for nephron progenitors. In vivo disruption of proline metabolism caused premature nephron progenitor exhaustion through their accelerated differentiation in pyrroline-5-carboxylate reductases 1 (Pycr1) and 2 (Pycr2) double-knockout kidneys. Pycr1/Pycr2-deficient progenitors showed normal cell survival, indicating no changes in cellular stress. Our results suggest that MAPK/ERK-dependent metabolism functionally participates in nephron progenitor maintenance by monitoring pyruvate and proline biogenesis in developing kidneys.


Asunto(s)
Sistema de Señalización de MAP Quinasas , Organogénesis , Aminoácidos/metabolismo , Animales , Diferenciación Celular/genética , Riñón/metabolismo , Ratones , Nefronas/metabolismo , Oxidorreductasas/metabolismo , Prolina/metabolismo , Piruvatos/metabolismo , Células Madre/metabolismo
4.
Proc Natl Acad Sci U S A ; 119(32): e2120777119, 2022 08 09.
Artículo en Inglés | MEDLINE | ID: mdl-35917341

RESUMEN

Tipping elements are nonlinear subsystems of the Earth system that have the potential to abruptly shift to another state if environmental change occurs close to a critical threshold with large consequences for human societies and ecosystems. Among these tipping elements may be the Amazon rainforest, which has been undergoing intensive anthropogenic activities and increasingly frequent droughts. Here, we assess how extreme deviations from climatological rainfall regimes may cause local forest collapse that cascades through the coupled forest-climate system. We develop a conceptual dynamic network model to isolate and uncover the role of atmospheric moisture recycling in such tipping cascades. We account for heterogeneity in critical thresholds of the forest caused by adaptation to local climatic conditions. Our results reveal that, despite this adaptation, a future climate characterized by permanent drought conditions could trigger a transition to an open canopy state particularly in the southern Amazon. The loss of atmospheric moisture recycling contributes to one-third of the tipping events. Thus, by exceeding local thresholds in forest adaptive capacity, local climate change impacts may propagate to other regions of the Amazon basin, causing a risk of forest shifts even in regions where critical thresholds have not been crossed locally.


Asunto(s)
Sequías , Bosque Lluvioso , Cambio Climático , Árboles
5.
Plant Mol Biol ; 114(3): 63, 2024 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-38805152

RESUMEN

Senescence is a multifaceted and dynamic developmental phase pivotal in the plant's lifecycle, exerting significant influence and involving intricate regulatory mechanisms marked by a variety of structural, biochemical and molecular alterations. Biochemical changes, including reactive oxygen species (ROS) generation, membrane deterioration, nucleic acid degradation and protein degradation, characterize flower senescence. The progression of senescence entails a meticulously orchestrated network of interconnected molecular mechanisms and signalling pathways, ensuring its synchronized and efficient execution. Within flowering plants, petal senescence emerges as a crucial aspect significantly impacting flower longevity and postharvest quality, emphasizing the pressing necessity of unravelling the underlying signalling cascades orchestrating this process. Understanding the complex signalling pathways regulating petal senescence holds paramount importance, not only shedding light on the broader phenomenon of plant senescence but also paving the way for the development of targeted strategies to enhance the postharvest longevity of cut flowers. Various signalling pathways participate in petal senescence, encompassing hormone signalling, calcium signalling, protein kinase signalling and ROS signalling. Among these, the ethylene signalling pathway is extensively studied, and the manipulation of genes associated with ethylene biosynthesis or signal transduction has demonstrated the potential to enhance flower longevity. A thorough understanding of these complex pathways is critical for effectively delaying flower senescence, thereby enhancing postharvest quality and ornamental value. Therefore, this review adopts a viewpoint that combines fundamental research into the molecular intricacies of senescence with a practical orientation towards developing strategies for improving the postharvest quality of cut flowers. The innovation of this review is to shed light on the pivotal signalling cascades underpinning flower senescence and offer insights into potential approaches for modulating these pathways to postpone petal senescence in ornamental plants.


Asunto(s)
Muerte Celular , Flores , Especies Reactivas de Oxígeno , Transducción de Señal , Flores/genética , Flores/fisiología , Flores/crecimiento & desarrollo , Especies Reactivas de Oxígeno/metabolismo , Etilenos/metabolismo , Senescencia de la Planta/genética , Regulación de la Expresión Génica de las Plantas , Reguladores del Crecimiento de las Plantas/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética
6.
Plant Cell Physiol ; 65(3): 390-404, 2024 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-38153765

RESUMEN

Mitogen-activated protein kinase (MAPK) cascades are conserved signaling pathways that transduce extracellular signals into diverse cellular responses. Arabidopsis MAPKKK18 is a component of the MAPKKK17/18-MKK3-MPK1/2/7/14 cascades, which play critical roles in abscisic acid (ABA) signaling, drought tolerance and senescence. A very important aspect of MAP kinase signaling is both its activation and its termination, which must be tightly controlled to achieve appropriate biological responses. Recently, the ubiquitin-proteasome system (UPS) has received increasing attention as a key mechanism for maintaining the homeostasis of MAPK cascade components and other ABA signaling effectors. Previous studies have shown that the stability of MAPKKK18 is regulated by the UPS via the ABA core pathway. Here, using multiple proteomic approaches, we found that MAPKKK17/18 turnover is tightly controlled by three E3 ligases, UPL1, UPL4 and KEG. We also identified lysines 154 and 237 as critical for MAPKKK18 stability. Taken together, this study sheds new light on the mechanism that controls MAPKKK17/18 activity and function.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Ácido Abscísico/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteómica , Complejo de la Endopetidasa Proteasomal/metabolismo , Ubiquitina/metabolismo , Quinasas Quinasa Quinasa PAM/metabolismo
7.
Small ; 20(4): e2304578, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37732702

RESUMEN

Artificial reconstruction of naturally evolved principles, such as compartmentalization and cascading of multienzyme complexes, offers enormous potential for the development of biocatalytic materials and processes. Due to their unique addressability at the nanoscale, DNA origami nanostructures (DON) have proven to be an exceptionally powerful tool for studying the fundamental processes in biocatalytic cascades. To systematically investigate the diffusion-reaction network of (co)substrate transfer in enzyme cascades, a model system of stereoselective ketoreductase (KRED) with cofactor regenerating enzyme is assembled in different spatial arrangements on DNA nanostructures and is located in the sphere of microbeads (MB) as a spatially confining nano- and microenvironment, respectively. The results, obtained through the use of highly sensitive analytical methods, Western blot-based quantification of the enzymes, and mass spectrometric (MS) product detection, along with theoretical modeling, provide strong evidence for the presence of two interacting compartments, the diffusion layers around the microbead and the DNA scaffold, which influence the catalytic efficiency of the cascade. It is shown that the microscale compartment exerts a strong influence on the productivity of the cascade, whereas the nanoscale arrangement of enzymes has no influence but can be modulated by the insertion of a diffusion barrier.


Asunto(s)
ADN , Nanoestructuras , ADN/química , Nanoestructuras/química , Complejos Multienzimáticos/química , Complejos Multienzimáticos/metabolismo , Biocatálisis , Catálisis
8.
Small ; : e2404018, 2024 Aug 12.
Artículo en Inglés | MEDLINE | ID: mdl-39133083

RESUMEN

The designed and ordered co-immobilization of multiple enzymes for vectorial biocatalysis is challenging. Here, a combination of protein phase separation and bioorthogonal linking is used to generate a zeolitic imidazole framework (ZIF-8) containing co-immobilized enzymes. Zn2+ ions induce the clustering of minimal protein modules, such as 6-His tag, proline-rich motif (PRM) and SRC homology 3 (SH3) domains, and allow for phase separation of the coupled aldoketoreductase (AKR) and alcohol dehydrogenase (ADH) at low concentrations. This is achieved by fusing SpyCatcher and PRM-SH3-6His peptide fragments to the C and N termini of AKR, respectively, and the SpyTag to ADH. Addition of 2-methylimidazole results in droplet formation and enables in situ spatial embedding the recombinant AKR and ADH to generate the cascade biocalysis system encapsulated in ZIF-8 (AAE@ZIF). In synthesizing (S)-1-(2-chlorophenyl) ethanol, ater 6 cycles, the yield can still reach 91%, with 99.99% enantiomeric excess (ee) value for each cycle. However, the yield could only reach 72.9% when traditionally encapsulated AKR and ADH in ZIF-8 are used. Thus, this work demonstrates that a combination of protein phase separation and bio-orthogonal linking enables the in situ creation of a stable and spatially organized bi-enzyme system with enhanced channeling effects in ZIF-8.

9.
Proc Biol Sci ; 291(2032): 20241112, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39378991

RESUMEN

Large mammalian herbivores (LMH) are important functional components and drivers of biodiversity and ecosystem functioning in grasslands. Yet their role in regulating food-web dynamics and trophic cascades remains poorly understood. In the temperate grasslands of northern China, we explored whether and how grazing domestic cattle (Bos taurus) alter the predator-prey interactions between a dominant grasshopper (Euchorthippus unicolor) and its avian predator the barn swallow (Hirundo rustica). Using two large manipulative field experiments, we found that in the presence of cattle, grasshoppers increased their jumping frequency threefold, swallows increased foraging visits to these fields sixfold, and grasshopper density was reduced by about 50%. By manipulatively controlling the grasshoppers' ability to jump, we showed that jumping enables grasshoppers to avoid being incidentally consumed or trampled by cattle. However, jumping behaviour increased their consumption rates by swallows 37-fold compared with grasshoppers that were unable to jump. Our findings illustrate how LMH can indirectly alter predator-prey interactions by affecting behaviour of avian predators and herbivorous insects. These non-plant-mediated effects of LMH may influence trophic interactions in other grazing ecosystems and shape community structure and dynamics. We highlight that convoluted multispecies interactions may better explain how LMH control food-web dynamics in grasslands.


Asunto(s)
Cadena Alimentaria , Saltamontes , Herbivoria , Conducta Predatoria , Animales , Saltamontes/fisiología , China , Bovinos/fisiología , Golondrinas/fisiología , Pradera
10.
Chembiochem ; 25(2): e202300673, 2024 01 15.
Artículo en Inglés | MEDLINE | ID: mdl-37994376

RESUMEN

The in vitro synthesis of Coenzyme A (CoA)-thioester intermediates opens new avenues to transform simple molecules into more complex and multifunctional ones by assembling cell-free biosynthetic cascades. In this review, we have systematically cataloged known CoA-dependent enzyme reactions that have been successfully implemented in vitro. To faciliate their identification, we provide their UniProt ID when available. Based on this catalog, we have organized enzymes into three modules: activation, modification, and removal. i) The activation module includes enzymes capable of fusing CoA with organic molecules. ii) The modification module includes enzymes capable of catalyzing chemical modifications in the structure of acyl-CoA intermediates. And iii) the removal module includes enzymes able to remove the CoA and release an organic molecule different from the one activated in the upstream. Based on these reactions, we constructed a reaction network that summarizes the most relevant CoA-dependent biosynthetic pathways reported until today. From the information available in the articles, we have plotted the total turnover number of CoA as a function of the product titer, observing a positive correlation between both parameters. Therefore, the success of a CoA-dependent in vitro pathway depends on its ability to regenerate CoA, but also to regenerate other cofactors such as NAD(P)H and ATP.


Asunto(s)
Acilcoenzima A , NAD , Acilcoenzima A/metabolismo , NAD/metabolismo , Coenzima A/metabolismo
11.
Annu Rev Microbiol ; 73: 621-638, 2019 09 08.
Artículo en Inglés | MEDLINE | ID: mdl-31226022

RESUMEN

Bacteria need to deliver large molecules out of the cytosol to the extracellular space or even across membranes of neighboring cells to influence their environment, prevent predation, defeat competitors, or communicate. A variety of protein-secretion systems have evolved to make this process highly regulated and efficient. The type VI secretion system (T6SS) is one of the largest dynamic assemblies in gram-negative bacteria and allows for delivery of toxins into both bacterial and eukaryotic cells. The recent progress in structural biology and live-cell imaging shows the T6SS as a long contractile sheath assembled around a rigid tube with associated toxins anchored to a cell envelope by a baseplate and membrane complex. Rapid sheath contraction releases a large amount of energy used to push the tube and toxins through the membranes of neighboring target cells. Because reach of the T6SS is limited, some bacteria dynamically regulate its subcellular localization to precisely aim at their targets and thus increase efficiency of toxin translocation.


Asunto(s)
Bacterias Gramnegativas/metabolismo , Sistemas de Secreción Tipo VI , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Sistemas de Secreción Bacterianos , Membrana Celular/metabolismo , Escherichia coli/metabolismo , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/metabolismo , Lipoproteínas/química , Lipoproteínas/metabolismo , Transducción de Señal , Sistemas de Secreción Tipo VI/biosíntesis , Sistemas de Secreción Tipo VI/química , Sistemas de Secreción Tipo VI/metabolismo , Sistemas de Secreción Tipo VI/ultraestructura
12.
Exp Eye Res ; 240: 109796, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38244883

RESUMEN

To investigate the metabolic difference among tissue layers of the rabbits' eye during the development of myopia using metabolomic techniques and explore any metabolic links or cascades within the ocular wall. Ultra Performance Liquid Chromatography - Mass Spectrometry (UPLC-MS) was utilized for untargeted metabolite screening (UMS) to identify the significant differential metabolites produced between myopia (MY) and control (CT) (horizontal). Subsequently, we compared those key metabolites among tissues (Sclera, Choroid, Retina) of MY for distribution and variation (longitudinal). A total of 6285 metabolites were detected in the three tissues. The differential metabolites were screened and the metabolic pathways of these metabolites in each myopic tissue were labeled, including tryptophan and its metabolites, pyruvate, taurine, caffeine metabolites, as well as neurotransmitters like glutamate and dopamine. Our study suggests that multiple metabolic pathways or different metabolites under the same pathway, might act on different parts of the eyeball and contribute to the occurrence and development of myopia by affecting the energy supply to the ocular tissues, preventing antioxidant stress, affecting scleral collagen synthesis, and regulating various neurotransmitters mutually.


Asunto(s)
Miopía , Espectrometría de Masas en Tándem , Animales , Conejos , Cromatografía Liquida , Modelos Animales de Enfermedad , Miopía/metabolismo , Retina/metabolismo , Esclerótica/metabolismo , Neurotransmisores/metabolismo
13.
J Theor Biol ; 583: 111769, 2024 04 21.
Artículo en Inglés | MEDLINE | ID: mdl-38423206

RESUMEN

Oxygen (O2) regulated pathways modulate B cell activation, migration and proliferation during infection, vaccination, and other diseases. Modeling these pathways in health and disease is critical to understand B cell states and ways to mediate them. To characterize B cells by their activation of O2 regulated pathways we develop pathway specific discrete state models using previously published single-cell RNA-sequencing (scRNA-seq) datasets from isolated B cells. Specifically, Single Cell Boolean Omics Network Invariant-Time Analysis (scBONITA) was used to infer logic gates for known pathway topologies. The simplest inferred set of logic gates that maximized the number of "OR" interactions between genes was used to simulate B cell networks involved in oxygen sensing until they reached steady network states (attractors). By focusing on the attractors that best represented sequenced cells, we identified genes critical in determining pathway specific cellular states that corresponded to diseased and healthy B cell phenotypes. Specifically, we investigate the transendothelial migration, regulation of actin cytoskeleton, HIF1A, and Citrate Cycle pathways. Our analysis revealed attractors that resembled the state of B cell exhaustion in HIV+ patients as well as attractors that promoted anerobic metabolism, angiogenesis, and tumorigenesis in breast cancer patients, which were eliminated after neoadjuvant chemotherapy (NACT). Finally, we investigated the attractors to which the Azimuth-annotated B cells mapped and found that attractors resembling B cells from HIV+ patients encompassed a significantly larger number of atypical memory B cells than HIV- attractors. Meanwhile, attractors resembling B cells from breast cancer patients post NACT encompassed a reduced number of atypical memory B cells compared to pre-NACT attractors.


Asunto(s)
Neoplasias de la Mama , Infecciones por VIH , Humanos , Femenino , Algoritmos , Oxígeno , Redes Reguladoras de Genes
14.
J Anim Ecol ; 2024 Jul 24.
Artículo en Inglés | MEDLINE | ID: mdl-39045801

RESUMEN

Birds, bats and ants are recognised as significant arthropod predators. However, empirical studies reveal inconsistent trends in their relative roles in top-down control across strata. Here, we describe the differences between forest strata in the separate effects of birds, bats and ants on arthropod densities and their cascading effects on plant damage. We implemented a factorial design to exclude vertebrates and ants in both the canopy and understorey. Additionally, we separately excluded birds and bats from the understorey using diurnal and nocturnal exclosures. At the end of the experiments, we collected all arthropods and assessed herbivory damage. Arthropods responded similarly to predator exclusion across forest strata, with a density increase of 81% on trees without vertebrates and 53% without both vertebrates and ants. Additionally, bird exclusion alone led to an 89% increase in arthropod density, while bat exclusion resulted in a 63% increase. Herbivory increased by 42% when vertebrates were excluded and by 35% when both vertebrates and ants were excluded. Bird exclusion alone increased herbivory damage by 28%, while the exclusion of bats showed a detectable but non-significant increase (by 22%). In contrast, ant exclusion had no significant effect on arthropod density or herbivory damage across strata. Our results reveal that the effects of birds and bats on arthropod density and herbivory damage are similar between the forest canopy and understorey in this temperate forest. In addition, ants were not found to be significant predators in our system. Furthermore, birds, bats and ants appeared to exhibit antagonistic relationships in influencing arthropod density. These findings highlight, unprecedentedly, the equal importance of birds and bats in maintaining ecological balance across different strata of a temperate forest.

15.
J Anim Ecol ; 93(6): 654-658, 2024 06.
Artículo en Inglés | MEDLINE | ID: mdl-38708817

RESUMEN

Research Highlight: Piccoli, G. C. d. O., Antiqueira, P. A. P., Srivastava, D. S., & Romero, G. Q. (2024). Trophic cascades within and across ecosystems: The role of anti-predatory defences, predator type and detritus quality. Journal of Animal Ecology, 00, 1-14. https://doi.org/10.1111/1365-2656.14063. Ecosystem functioning is controlled by the interplay between bottom-up supply of limiting nutrients and top-down animal feedback effects. However, the degree of animal versus nutrient control is context-dependent. A key challenge lies in characterizing this context dependency which is hypothesized to depend on differences in animal functional traits. Reporting on an important experiment, Piccoli et al. (2014) evaluate how interactions among functionally different predators and decomposer prey create context dependency in top-down control of a model system-tropical bromeliad tank ecosystems. Bromeliad plants hold water in their tanks supporting microcosm ecosystems containing terrestrial and aquatic insect larvae and arachnids. The ecosystems are supported by nutrients in plant litter that rains down from forest canopies into the tanks. Nutrients are released after litter is decomposed by a functionally diverse community of larval insect decomposers that differ in feeding mode and antipredator defence strategy. This decomposer community is preyed upon by an exclusively narrowly ranging aquatic insect larval predator and widely ranging spider predator that crosses between the aquatic and surrounding terrestrial ecosystems. Experimental manipulation of the animal community to test for the degree of control by predators mediated by the functionally diverse prey community included four treatments: (i) a control with the detritivores composing different function groups but without predators, (ii) the cross-ecosystem spider predator added, (iii) the purely aquatic damselfly larvae predator added and (iv) both predator types added to capture their interacting effect on ecosystem function (decomposition, nutrient release, and plant growth). Notably, the study resolved the causal pathways and strengths of direct and indirect control using structural equation modelling. These findings reveal how context dependency arises due to different capacities of the predators alone and together to overcome prey defences and control their abundances, with attendant cascading effects that diminished as well as enhanced decomposition and nutrient release to support bromeliad plant production. The study reveals that predators have a decided, albeit qualitatively and quantitatively different, hand in shaping the degree of bottom-up control through feedback effect on the release of limiting nutrients. This ground-breaking study provides a way forward in understanding the mechanisms determining context dependency in the control over ecosystem functioning.


Asunto(s)
Cadena Alimentaria , Conducta Predatoria , Animales , Insectos/fisiología , Bromeliaceae/fisiología , Ecosistema , Larva/fisiología , Larva/crecimiento & desarrollo , Arácnidos/fisiología
16.
AIDS Behav ; 28(4): 1137-1151, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-37462890

RESUMEN

Adolescent girls and young women (AGYW) in South Africa are at a three times higher risk of acquiring HIV than their male counterparts. The HIV prevention cascade is a tool which can be used to measure coverage of HIV prevention services, although there is limited empirical evidence to demonstrate its application in low-resourced settings. The unifying framework is a conceptualisation of the HIV prevention cascade which theorises that both motivation and access are required for an individual to effectively use an HIV prevention method. We applied this framework to data from a random sample of 127,951 beneficiaries of a combination HIV prevention programme for AGYW aged 15-24 in South Africa to measure the steps to, and identify key barriers to, effective use of male condoms and oral pre-exposure prophylaxis (PrEP) among this vulnerable population. Barriers to each step were analysed using univariate and multivariable logistic regression. Among self-reported HIV-negative AGYW who had sex in the past 6 months, effective use of condoms (15.2%), access to PrEP (39.1%) and use of PrEP (3.8%) were low. AGYW were: less likely to be motivated to use condoms if they believed that they had a faithful partner (aOR 0.44, 95% CI 0.22-0.90) or disliked condoms (aOR 0.26, 95% CI 0.11-0.57), less likely to access condoms if the place where AGYW accessed them was far away (aOR 0.25, 95% CI 0.10-0.64), more likely to effectively use condoms if they received counselling on how to use them (aOR 2.24, 95% CI 1.05-4.76), less likely to be motivated to use PrEP if they did not believe PrEP was efficacious (aOR 0.35, 95% CI 0.17-0.72), more likely to be motivated if they felt confident that they could use PrEP, and more likely to have access to PrEP if they had ever been offered PrEP (aOR 2.94, 95% CI 1.19-7.22). This combination HIV prevention programme and similar programmes should focus on risk-reduction counselling interventions for AGYW and their male partners to improve effective use of condoms and ensure easy access to condoms and PrEP by making them available in youth-friendly spaces. Our findings demonstrate that the application of HIV prevention cascades can inform AGYW HIV prevention programming in low-resourced settings.


Asunto(s)
Fármacos Anti-VIH , Infecciones por VIH , Profilaxis Pre-Exposición , Humanos , Masculino , Adolescente , Femenino , Infecciones por VIH/epidemiología , Infecciones por VIH/prevención & control , Infecciones por VIH/tratamiento farmacológico , Sudáfrica/epidemiología , Profilaxis Pre-Exposición/métodos , Condones , Motivación , Fármacos Anti-VIH/uso terapéutico
17.
Age Ageing ; 53(6)2024 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-38851215

RESUMEN

INTRODUCTION: Problematic polypharmacy is the prescribing of five or more medications potentially inappropriately. Unintentional prescribing cascades represent an under-researched aspect of problematic polypharmacy and occur when an adverse drug reaction (ADR) is misinterpreted as a new symptom resulting in the initiation of a new medication. The aim of this study was to elicit key stakeholders' perceptions of and attitudes towards problematic polypharmacy, with a focus on prescribing cascades. METHODS: qualitative one-to-one semi-structured interviews were conducted with predefined key stakeholder groups. Inductive thematic analysis was employed. RESULTS: Thirty-one stakeholders were interviewed: six patients, two carers, seven general practitioners, eight pharmacists, four hospital doctors, two professional organisation representatives and two policymakers. Three main themes were identified: (i) ADRs and prescribing cascades-a necessary evil. Healthcare professionals (HCPs) expressed concern that experiencing an ADR would negatively impact patients' confidence in their doctor. However, patients viewed ADRs pragmatically as an unpredictable risk. (ii) Balancing the risk/benefit tipping point. The complexity of prescribing decisions in the context of polypharmacy made balancing this tipping point challenging. Consequently, HCPs avoided medication changes. (iii) The minefield of medication reconciliation. Stakeholders, including patients and carers, viewed medication reconciliation as a perilous activity due to systemic communication deficits. CONCLUSION: Stakeholders believed that at a certain depth of polypharmacy, the risk that a new symptom is being caused by an existing medication becomes incalculable. Therefore, in the absence of harm, medication changes were avoided. However, medication reconciliation post hospital discharge compelled prescribing decisions and was seen as a high-risk activity by stakeholders.


Asunto(s)
Actitud del Personal de Salud , Prescripción Inadecuada , Polifarmacia , Investigación Cualitativa , Humanos , Masculino , Femenino , Anciano , Prescripción Inadecuada/prevención & control , Persona de Mediana Edad , Participación de los Interesados , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/psicología , Pautas de la Práctica en Medicina , Entrevistas como Asunto , Conocimientos, Actitudes y Práctica en Salud , Conciliación de Medicamentos , Anciano de 80 o más Años , Cuidadores/psicología , Medición de Riesgo , Percepción , Farmacéuticos
18.
Dev Psychopathol ; 36(1): 325-337, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36847260

RESUMEN

Little effort has been made to integrate developmental cascades with maternal/paternal parenting in a single investigation. The present study seeks to test cascading effects among academic and internalizing/externalizing symptoms and their associations with maternal/paternal parenting across three time points from 8 to 10 years. Data for this investigation came from a nationally representative prospective cohort study of children born in April through July of 2008 in South Korea who were followed up annually. The sample included 1,598 families (48.5% girls). Parents rated their parenting and teachers rated children's internalizing/externalizing problems and academic performance. Structural equation modeling showed that externalizing problems were negatively related to academic performance. Academic performance was negatively related to internalizing problems and positively related to maternal/paternal authoritative parenting, which in turn led to children's higher academic performance. Bidirectional relations were found between academic performance and externalizing problems and between paternal authoritative parenting and children's internalizing problems. Findings suggested cascading effects and their associations with parenting were not attributable to child gender, intelligence, or socioeconomic differences. These findings lend support to adjustment erosion and academic incompetence models and underscore the need for greater attention to the role that fathering may play in children's development and mothering.


Asunto(s)
Rendimiento Académico , Responsabilidad Parental , Masculino , Niño , Femenino , Humanos , Estudios Prospectivos , Padre , Padres
19.
Dev Psychopathol ; : 1-14, 2024 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-38934483

RESUMEN

This study examines associations between early childhood attachment security and adolescent personality functioning in a high-risk sample within a developmental psychopathology framework. Data from 2,268 children (1165 male; 1103 female) and caregivers participating in Future of Families and Child Well-Being Study (FFCWS) were used to examine (1) effects of genetic polymorphisms of the serotonin transporter (5-HTTLPR) and dopamine D4 receptor (DRD4) genes and adverse childhood experiences (ACEs) on attachment security and emotional and behavioral dysregulation in early childhood and (2) longitudinal associations and transactional relationships among attachment security, dysregulation, negative parenting attitudes and behaviors, social competence, and adolescent personality functioning. Results revealed that ACEs predicted attachment security over and above sex or the genetic risk, and gene × environment interactions did not increment prediction. Results of cascade models showed that greater early childhood attachment security predicted higher adolescent level of personality functioning via pathways through intermediary variables. Limitations and future research directions are discussed.

20.
BMC Ophthalmol ; 24(1): 82, 2024 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-38388341

RESUMEN

BACKGROUND: Branch retinal vein occlusion (BRVO) is a common retinal vascular disease leading to severe vision loss and blindness. This study aimed to investigate and reveal the pathophysiological mechanisms underlying macular edema (ME) recurrence in patients with BRVO through a proteomic approach. METHODS: We detected proteins in the aqueous humor of 14 untreated, four refractory, and four post-operative patients with BRVO-ME and 12 age-matched cataract controls using four-dimensional label-free proteomic and bioinformatics analyses. RESULTS: In total, 84 proteins exhibited significant differential expression between the BRVO and control samples (fold change [FC] ≥ 1.2 and adjusted p-value < 0.05). Compared to the control group, 43 and 41 proteins were upregulated and downregulated, respectively, in the BRVO group. These proteins were involved in cell adhesion, visual perception, retina homeostasis, and platelet activation. Several significantly enriched signaling pathways included complement and coagulation cascades and platelet activation. In the protein-protein interaction networks generated using the search tool for retrieval of interacting genes (STRING), the fibrinogen alpha chain and fibrinogen beta chain constituted a tightly connected cluster. Many common protein expression trends, such as the fibrinogen alpha chain and fibrinogen beta chain, were observed in both the recurrent and refractory groups. Differentially expressed proteins in the two groups were involved in complement activation, acute-phase response, platelet activation, and platelet aggregation. Important signaling pathways include the complement and coagulation cascades, and platelet activation. Protein-protein interaction analysis suggested that the fibrinogen alpha chain and fibrinogen beta chain constituted a tightly connected cluster. The expression of some differentially expressed proteins shared by the BRVO and the recurrent and refractory groups was reversed in the post-operative group. CONCLUSIONS: Our study is the first to analyze the proteomics of recurrent, refractory, and post-operative groups treated for BRVO-ME, and may potentially provide novel therapeutic interventions for the recurrence of ME.


Asunto(s)
Edema Macular , Oclusión de la Vena Retiniana , Humanos , Oclusión de la Vena Retiniana/tratamiento farmacológico , Edema Macular/tratamiento farmacológico , Proteómica/métodos , Fibrinógeno/uso terapéutico
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