RESUMEN

Group A streptococci (GAS) are highly prevalent human pathogens whose primary ecological niche is the superficial epithelial layers of the throat and/or skin. Many GAS strains with a strong tendency to cause pharyngitis are distinct from strains that tend to cause impetigo; thus, genetic differences between them may confer host tissue-specific virulence. In this study, the FbaA surface protein gene was found to be present in most skin specialist strains but largely absent from a genetically related subset of pharyngitis isolates. In an ΔfbaA mutant constructed in the impetigo strain Alab49, loss of FbaA resulted in a slight but significant decrease in GAS fitness in a humanized mouse model of impetigo; the ΔfbaA mutant also exhibited decreased survival in whole human blood due to phagocytosis. In assays with highly sensitive outcome measures, Alab49ΔfbaA was compared to other isogenic mutants lacking virulence genes known to be disproportionately associated with classical skin strains. FbaA and PAM (i.e., the M53 protein) had additive effects in promoting GAS survival in whole blood. The pilus adhesin tip protein Cpa promoted Alab49 survival in whole blood and appears to fully account for the antiphagocytic effect attributable to pili. The finding that numerous skin strain-associated virulence factors make slight but significant contributions to virulence underscores the incremental contributions to fitness of individual surface protein genes and the multifactorial nature of GAS-host interactions.

Asunto(s)

Proteínas Bacterianas/genética , Proteínas Portadoras/genética , Regulación Bacteriana de la Expresión Génica , Infecciones Estreptocócicas/microbiología , Streptococcus pyogenes/genética , Streptococcus pyogenes/patogenicidad , Animales , Proteínas Bacterianas/metabolismo , Células Sanguíneas/inmunología , Células Sanguíneas/microbiología , Proteínas Portadoras/metabolismo , Modelos Animales de Enfermedad , Fructosa-Bifosfato Aldolasa , Aptitud Genética , Interacciones Huésped-Patógeno , Humanos , Impétigo/inmunología , Impétigo/microbiología , Impétigo/patología , Ratones , Faringitis/inmunología , Faringitis/microbiología , Faringitis/patología , Faringe/inmunología , Faringe/microbiología , Faringe/patología , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Piel/inmunología , Piel/microbiología , Piel/patología , Infecciones Estreptocócicas/inmunología , Infecciones Estreptocócicas/patología , Streptococcus pyogenes/metabolismo , Virulencia

RESUMEN

The secreted cysteine proteinase SpeB is an important virulence factor of group A streptococci (GAS), whereby SpeB activity varies widely among strains. To establish the degree to which SpeB activity correlates with disease, GAS organisms were recovered from patients with pharyngitis, impetigo, invasive disease or acute rheumatic fever (ARF), and selected for analysis using rigorous sampling criteria; >300 GAS isolates were tested for SpeB activity by casein digestion assays, and each GAS isolate was scored as a SpeB-producer or non-producer. Highly significant statistical differences (p < 0.01) in SpeB production are observed between GAS recovered from patients with ARF (41.5% SpeB-non-producers) compared to pharyngitis (20.5%), invasive disease (16.7%), and impetigo (5.5%). SpeB activity differences between pharyngitis and impetigo isolates are also significant, whereas pharyngitis versus invasive isolates show no significant difference. The disproportionately greater number of SpeB-non-producers among ARF-associated isolates may indicate an altered transcriptional program for many rheumatogenic strains and/or a protective role for SpeB in GAS-triggered autoimmunity.

Asunto(s)

Proteínas Bacterianas/genética , Exotoxinas/genética , Fiebre Reumática/microbiología , Streptococcus pyogenes/aislamiento & purificación , Humanos , Impétigo/microbiología , Faringitis/microbiología , Infecciones Estreptocócicas/microbiología , Streptococcus pyogenes/enzimología , Streptococcus pyogenes/genética

RESUMEN

Circular (circ)RNAs have recently become a subject of great biologic interest. It is now clear that they represent a diverse and abundant class of RNAs with regulated expression and evolutionarily conserved functions. There are several mechanisms by which RNA circularization can occur in vivo. Here, we focus on the biogenesis of tRNA intronic circular RNAs (tricRNAs) in archaea and animals, and we detail their use as research tools for orthogonal, directed circRNA expression in vivo.

Asunto(s)

Aptámeros de Nucleótidos/genética , Ingeniería Genética/métodos , Precursores del ARN/genética , Sitios de Empalme de ARN , Empalme del ARN , ARN de Transferencia/genética , ARN/genética , Animales , Aptámeros de Nucleótidos/metabolismo , Archaea/genética , Archaea/metabolismo , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Exones , Células HEK293 , Células HeLa , Humanos , Intrones , Ratones , ARN/metabolismo , Precursores del ARN/metabolismo , ARN Circular , ARN de Transferencia/metabolismo , Empalmosomas/metabolismo , Empalmosomas/ultraestructura

RESUMEN

In this paper, we present a technique for dimensionality reduction in hyperspectral imaging during the data collection process. A four-channel hyperspectral imager using liquid crystal Fabry-Perot etalons has been built and used to verify this method for four applications: auroral imaging, plant study, landscape classification, and anomaly detection. This imager is capable of making measurements simultaneously in four wavelength ranges while being tunable within those ranges, and thus can be used to measure narrow contiguous bands in four spectral domains. In this paper, we describe the design, concept of operation, and deployment of this instrument. The results from preliminary testing of this instrument are discussed and are promising and demonstrate this instrument as a good candidate for hyperspectral imaging.

RESUMEN

A four channel hyperspectral imager using Liquid Crystal Fabry-Perot (LCFP) etalons has been built and tested. This imager is capable of making measurements simultaneously in four wavelength ranges in the visible spectrum. The instrument was designed to make measurements of natural airglow and auroral emissions in the upper atmosphere of the Earth and was installed and tested at the Poker Flat Research Range in Fairbanks, Alaska from February to April 2014. The results demonstrate the capabilities and challenges this instrument presents as a sensor for aeronomical studies.

RESUMEN

We report the discovery of a class of abundant circular noncoding RNAs that are produced during metazoan tRNA splicing. These transcripts, termed tRNA intronic circular (tric)RNAs, are conserved features of animal transcriptomes. Biogenesis of tricRNAs requires anciently conserved tRNA sequence motifs and processing enzymes, and their expression is regulated in an age-dependent and tissue-specific manner. Furthermore, we exploited this biogenesis pathway to develop an in vivo expression system for generating "designer" circular RNAs in human cells. Reporter constructs expressing RNA aptamers such as Spinach and Broccoli can be used to follow the transcription and subcellular localization of tricRNAs in living cells. Owing to the superior stability of circular vs. linear RNA isoforms, this expression system has a wide range of potential applications, from basic research to pharmaceutical science.

Asunto(s)

Drosophila/genética , ARN de Transferencia/química , ARN de Transferencia/genética , ARN/química , ARN/metabolismo , Animales , Femenino , Genes Reporteros , Células HEK293 , Humanos , Intrones , Masculino , Modelos Moleculares , Conformación de Ácido Nucleico , Estabilidad del ARN , ARN Circular , Transcriptoma

RESUMEN

Mutations in the human survival motor neuron 1 (SMN) gene are the primary cause of spinal muscular atrophy (SMA), a devastating neuromuscular disorder. SMN protein has a well-characterized role in the biogenesis of small nuclear ribonucleoproteins (snRNPs), core components of the spliceosome. Additional tissue-specific and global functions have been ascribed to SMN; however, their relevance to SMA pathology is poorly understood and controversial. Using Drosophila as a model system, we created an allelic series of twelve Smn missense mutations, originally identified in human SMA patients. We show that animals expressing these SMA-causing mutations display a broad range of phenotypic severities, similar to the human disease. Furthermore, specific interactions with other proteins known to be important for SMN's role in RNP assembly are conserved. Intragenic complementation analyses revealed that the three most severe mutations, all of which map to the YG box self-oligomerization domain of SMN, display a stronger phenotype than the null allele and behave in a dominant fashion. In support of this finding, the severe YG box mutants are defective in self-interaction assays, yet maintain their ability to heterodimerize with wild-type SMN. When expressed at high levels, wild-type SMN is able to suppress the activity of the mutant protein. These results suggest that certain SMN mutants can sequester the wild-type protein into inactive complexes. Molecular modeling of the SMN YG box dimer provides a structural basis for this dominant phenotype. These data demonstrate that important structural and functional features of the SMN YG box are conserved between vertebrates and invertebrates, emphasizing the importance of self-interaction to the proper functioning of SMN.

Asunto(s)

Proteínas de Drosophila/genética , Drosophila/genética , Atrofia Muscular Espinal/genética , Proteínas de Unión al ARN/genética , Proteínas del Complejo SMN/genética , Animales , Modelos Animales de Enfermedad , Proteínas de Drosophila/química , Humanos , Neuronas Motoras/patología , Atrofia Muscular Espinal/patología , Mutación Missense/genética , Fenotipo , Multimerización de Proteína/genética , Proteínas de Unión al ARN/química , Ribonucleoproteínas Nucleares Pequeñas/genética , Proteínas del Complejo SMN/química , Relación Estructura-Actividad

RESUMEN

Here we report a human intellectual disability disease locus on chromosome 14q31.3 corresponding to mutation of the ZC3H14 gene that encodes a conserved polyadenosine RNA binding protein. We identify ZC3H14 mRNA transcripts in the human central nervous system, and we find that rodent ZC3H14 protein is expressed in hippocampal neurons and colocalizes with poly(A) RNA in neuronal cell bodies. A Drosophila melanogaster model of this disease created by mutation of the gene encoding the ZC3H14 ortholog dNab2, which also binds polyadenosine RNA, reveals that dNab2 is essential for development and required in neurons for normal locomotion and flight. Biochemical and genetic data indicate that dNab2 restricts bulk poly(A) tail length in vivo, suggesting that this function may underlie its role in development and disease. These studies reveal a conserved requirement for ZC3H14/dNab2 in the metazoan nervous system and identify a poly(A) RNA binding protein associated with a human brain disorder.

Asunto(s)

Proteínas de Drosophila/genética , Proteínas de Drosophila/fisiología , Discapacidad Intelectual/genética , Mutación , Proteínas Nucleares/genética , Proteínas Nucleares/fisiología , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/fisiología , Adolescente , Adulto , Secuencia de Aminoácidos , Animales , Sistema Nervioso Central/fisiología , Mapeo Cromosómico , Cromosomas Humanos Par 14/genética , Estudios de Cohortes , Consanguinidad , Secuencia Conservada , Drosophila melanogaster/genética , Drosophila melanogaster/fisiología , Evolución Molecular , Femenino , Vuelo Animal/fisiología , Técnicas de Silenciamiento del Gen , Genes Recesivos , Hipocampo/metabolismo , Humanos , Irán , Masculino , Modelos Animales , Datos de Secuencia Molecular , Linaje , Proteínas de Unión a Poli(A) , ARN Mensajero/genética , ARN Mensajero/metabolismo , Homología de Secuencia de Aminoácido , Adulto Joven , Dedos de Zinc/genética

RESUMEN

We demonstrate the use of a switchable circular-to-point converter (SCPC) device based on holographic polymer-dispersed liquid-crystal technology for application in lidar detection and optical telecommunication. A SCPC device converts the Fabry-Perot ring pattern into a single point or an array of points, while an external electrical field on the SCPC deactivates the conversion. Stacking different SCPC elements gives a random optical switch for applications in lidar detection and optical telecommunication. Two types of SCPC designs are analyzed and one is chosen and built for testing.