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1.
Nat Chem Biol ; 19(4): 451-459, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36482094

RESUMEN

Bacteria use two-component system (TCS) signaling pathways to sense and respond to peptides involved in host defense, quorum sensing and inter-bacterial warfare. However, little is known about the broad peptide-sensing capabilities of TCSs. In this study, we developed an Escherichia coli display method to characterize the effects of human antimicrobial peptides (AMPs) on the pathogenesis-regulating TCS PhoPQ of Salmonella Typhimurium with much higher throughput than previously possible. We found that PhoPQ senses AMPs with diverse sequences, structures and biological functions. We further combined thousands of displayed AMP variants with machine learning to identify peptide sub-domains and biophysical features linked to PhoPQ activation. Most of the newfound AMP activators induce PhoPQ in S. Typhimurium, suggesting possible roles in virulence regulation. Finally, we present evidence that PhoPQ peptide-sensing specificity has evolved across commensal and pathogenic bacteria. Our method enables new insights into the specificities, mechanisms and evolutionary dynamics of TCS-mediated peptide sensing in bacteria.


Asunto(s)
Proteínas Bacterianas , Escherichia coli , Humanos , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas Bacterianas/metabolismo , Bacterias/metabolismo , Salmonella typhimurium/metabolismo , Péptidos Catiónicos Antimicrobianos/farmacología , Regulación Bacteriana de la Expresión Génica
2.
Proc Natl Acad Sci U S A ; 118(20)2021 05 18.
Artículo en Inglés | MEDLINE | ID: mdl-33972436

RESUMEN

Metabolic changes associated with tissue inflammation result in significant extracellular acidosis (EA). Within mucosal tissues, intestinal epithelial cells (IEC) have evolved adaptive strategies to cope with EA through the up-regulation of SLC26A3 to promote pH homeostasis. We hypothesized that EA significantly alters IEC gene expression as an adaptive mechanism to counteract inflammation. Using an unbiased RNA sequencing approach, we defined the impact of EA on IEC gene expression to define molecular mechanisms by which IEC respond to EA. This approach identified a unique gene signature enriched in cyclic AMP response element-binding protein (CREB)-regulated gene targets. Utilizing loss- and gain-of-function approaches in cultured epithelia and murine colonoids, we demonstrate that EA elicits prominent CREB phosphorylation through cyclic AMP-independent mechanisms that requires elements of the mitogen-activated protein kinase signaling pathway. Further analysis revealed that EA signals through the G protein-coupled receptor GPR31 to promote induction of FosB, NR4A1, and DUSP1. These studies were extended to an in vivo murine model in conjunction with colonization of a pH reporter Escherichia coli strain that demonstrated significant mucosal acidification in the TNFΔARE model of murine ileitis. Herein, we observed a strong correlation between the expression of acidosis-associated genes with bacterial reporter sfGFP intensity in the distal ileum. Finally, the expression of this unique EA-associated gene signature was increased during active inflammation in patients with Crohn's disease but not in the patient control samples. These findings establish a mechanism for EA-induced signals during inflammation-associated acidosis in both murine and human ileitis.


Asunto(s)
Acidosis/genética , Antiportadores/genética , Enfermedad de Crohn/genética , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/genética , Ileítis/genética , Receptores Acoplados a Proteínas G/genética , Transportadores de Sulfato/genética , Acidosis/metabolismo , Acidosis/patología , Animales , Antiportadores/metabolismo , Enfermedad de Crohn/metabolismo , Enfermedad de Crohn/patología , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Modelos Animales de Enfermedad , Fosfatasa 1 de Especificidad Dual/genética , Fosfatasa 1 de Especificidad Dual/metabolismo , Regulación de la Expresión Génica , Humanos , Ileítis/metabolismo , Ileítis/patología , Íleon/metabolismo , Íleon/patología , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patología , Ratones , Ratones Endogámicos C57BL , Proteínas Quinasas Activadas por Mitógenos/genética , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Miembro 1 del Grupo A de la Subfamilia 4 de Receptores Nucleares/genética , Miembro 1 del Grupo A de la Subfamilia 4 de Receptores Nucleares/metabolismo , Organoides/metabolismo , Organoides/patología , Fosforilación , Proteínas Proto-Oncogénicas c-fos/genética , Proteínas Proto-Oncogénicas c-fos/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Análisis de Secuencia de ARN , Transducción de Señal , Transportadores de Sulfato/metabolismo
3.
Ophthalmic Plast Reconstr Surg ; 39(4): 361-365, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36757839

RESUMEN

PURPOSE: To characterize research productivity of ophthalmic plastic and reconstructive surgery (OPRS) fellows during residency. METHODS: A database was compiled of OPRS fellows listed on the American Society of Ophthalmic Plastic and Reconstructive Surgery (ASOPRS) Annual Fall Scientific Symposium program books who began their fellowship between 2012 and 2019. PubMed was searched for all publications published between July 1st of the year they began residency and September 30th of the year they began fellowship training. Bibliometric variables captured for each fellow included: the number of publications, first-author publications, and ophthalmology-related publications. RESULTS: A total of 197 OPRS fellows who began their fellowship training between 2012 and 2019 published a mean (± SD) of 2.42 ± 2.80 publications, 1.43 ± 1.85 first-author publications, and 2.33 ± 2.74 ophthalmology-related publications during residency. Linear regression revealed that the number of publications ( P < 0.001), first-author publications ( P < 0.001), and ophthalmology-related publications ( P < 0.001) that OPRS fellows published during residency have all significantly increased over the time assessed. CONCLUSIONS: The academic productivity of OPRS fellows during residency was quantified through bibliometric analysis to establish a national benchmark for the benefit of both prospective applicants and program directors. Residency research output of OPRS fellows has significantly increased between 2012 and 2019. Since ASOPRS program requirements necessitate academic productivity and thesis completion, publication records and involvement in research become valuable considerations when evaluating fellowship applicants. The knowledge of what accepted fellows have published provides the opportunity to make historical comparisons and may prove useful in the evaluation of the competitiveness of a given year's applicant pool.


Asunto(s)
Internado y Residencia , Oftalmología , Procedimientos de Cirugía Plástica , Cirugía Plástica , Humanos , Estados Unidos , Cirugía Plástica/educación , Educación de Postgrado en Medicina , Oftalmología/educación , Becas
4.
Appl Environ Microbiol ; 80(8): 2461-7, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24509931

RESUMEN

Nutrient sensors and developmental timers are two classes of genes vital to the establishment of early development in the social soil bacterium Myxococcus xanthus. The products of these genes trigger and regulate the earliest events that drive the colony from a vegetative state to aggregates, which ultimately leads to the formation of fruiting bodies and the cellular differentiation of the individual cells. In order to more accurately identify the genes and pathways involved in the initiation of this multicellular developmental program in M. xanthus, we adapted a method of growing vegetative populations within a constant controllable environment by using flow cell bioreactors, or flow cells. By establishing an M. xanthus community within a flow cell, we are able to test developmental responses to changes in the environment with fewer concerns for effects due to nutrient depletion or bacterial waste production. This approach allows for greater sensitivity in investigating communal environmental responses, such as nutrient sensing. To demonstrate the versatility of our growth environment, we carried out time-lapse confocal laser scanning microscopy to visualize M. xanthus biofilm growth and fruiting body development, as well as fluorescence staining of exopolysaccharides deposited by biofilms. We also employed the flow cells in a nutrient titration to determine the minimum concentration required to sustain vegetative growth. Our data show that by using a flow cell, M. xanthus can be held in a vegetative growth state at low nutrient concentrations for long periods, and then, by slightly decreasing the nutrient concentration, cells can be allowed to initiate the developmental program.


Asunto(s)
Técnicas Bacteriológicas/métodos , Reactores Biológicos/microbiología , Myxococcus xanthus/crecimiento & desarrollo , Adhesión Bacteriana , Biopelículas/crecimiento & desarrollo , Microscopía Confocal , Myxococcus xanthus/fisiología , Imagen de Lapso de Tiempo
5.
Ergonomics ; 38(5): 940-950, 1995 May.
Artículo en Inglés | MEDLINE | ID: mdl-29105611

RESUMEN

Experiments on fifteen simulated keyboards with different key sizes and inter-key spacings are reported. It was found that the movement time on these keyboards was well described by the model of Drury (Drury and Hoffmann 1992). Minimum movement times occurred when the inter-key spacing was approximately equal to the finger pad size. There was found to be an effect of the number of keys moved, which was not predicted by the model. This effect remained in a further experiment in which the target keys were marked.

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