RESUMEN

In this paper, we introduce SonoNERFs, a novel approach that adapts Neural Radiance Fields (NeRFs) to model and understand the echolocation process in bats, focusing on the challenges posed by acoustic data interpretation without phase information. Leveraging insights from the field of optical NeRFs, our model, termed SonoNERF, represents the acoustic environment through Neural Reflectivity Fields. This model allows us to reconstruct three-dimensional scenes from echolocation data, obtained by simulating how bats perceive their surroundings through sound. By integrating concepts from biological echolocation and modern computational models, we demonstrate the SonoNERF's ability to predict echo spectrograms for unseen echolocation poses and effectively reconstruct a mesh-based and energy-based representation of complex scenes. Our work bridges a gap in understanding biological echolocation and proposes a methodological framework that provides a first-order model of how scene understanding might arise in echolocating animals. We demonstrate the efficacy of the SonoNERF model on three scenes of increasing complexity, including some biologically relevant prey-predator interactions.

RESUMEN

Navigation in varied and dynamic indoor environments remains a complex task for autonomous mobile platforms. Especially when conditions worsen, typical sensor modalities may fail to operate optimally and subsequently provide inapt input for safe navigation control. In this study, we present an approach for the navigation of a dynamic indoor environment with a mobile platform with a single or several sonar sensors using a layered control system. These sensors can operate in conditions such as rain, fog, dust, or dirt. The different control layers, such as collision avoidance and corridor following behavior, are activated based on acoustic flow queues in the fusion of the sonar images. The novelty of this work is allowing these sensors to be freely positioned on the mobile platform and providing the framework for designing the optimal navigational outcome based on a zoning system around the mobile platform. Presented in this paper is the acoustic flow model used, as well as the design of the layered controller. Next to validation in simulation, an implementation is presented and validated in a real office environment using a real mobile platform with one, two, or three sonar sensors in real time with 2D navigation. Multiple sensor layouts were validated in both the simulation and real experiments to demonstrate that the modular approach for the controller and sensor fusion works optimally. The results of this work show stable and safe navigation of indoor environments with dynamic objects.

Asunto(s)

Robótica , Algoritmos , Simulación por Computador , Robótica/métodos , Sonido

RESUMEN

Pulse-echo sensing is the driving principle behind biological echolocation as well as biologically-inspired sonar and radar sensors. In biological echolocation, a single emitter sends a self-generated pulse into the environment which reflects off objects. A fraction of these reflections are captured by two receivers as echoes, from which information about the objects, such as their position in 3D space, can be deduced by means of timing, intensity and spectral analysis. This is opposed to frequency-modulated continuous-wave radar, which analyses the shift in frequency of the returning signal to determine distance, and requires an array of antenna to obtain directional information. In this work, we present a novel simulator which can generate synthetic pulse-echo measurements for a simulated sensor in a virtual environment. The simulation is implemented by replicating the relevant physical processes underlying the pulse-echo sensing modality, while achieving high performance at update rates above 50 Hz. The system is built to perform design space exploration of sensor hardware and software, with the goals of rapid prototyping and preliminary safety testing in mind. We demonstrate the validity of the simulator by replicating real-world experiments from previous work. In the first case, a subsumption architecture vehicle controller is set to navigate an unknown environment using the virtual sensor. We see the same trajectory pattern emerge in the simulated environment rebuilt from the real experiment, as well as similar activation times for the high-priority behaviors (±1.9%), and low-priority behaviors (±0.2%). In a second experiment, the simulated signals are used as input to a biologically-inspired direct simultaneous mapping and localization (SLAM) algorithm. Using only path integration, 83% of the positional errors are larger than 10 m, while for the SLAM algorithm 95% of the errors are smaller than 3.2  m. Additionally, we perform design space exploration using the simulator. By creating a synthetic radiation pattern with increased spatiospectral variance, we are able to reduce the average localization error of the system by 11%. From these results, we conclude that the simulation is sufficiently accurate to be of use in developing vehicle controllers and SLAM algorithms for pulse-echo radar sensors.

Asunto(s)

Radar , Algoritmos , Animales , Simulación por Computador , Ecolocación , Sonido

RESUMEN

Salicylic acid (SA) and jasmonic acid (JA) cross-communicate in the plant immune signaling network to finely regulate induced defenses. In Arabidopsis, SA antagonizes many JA-responsive genes, partly by targeting the ETHYLENE RESPONSE FACTOR (ERF)-type transcriptional activator ORA59. Members of the ERF transcription factor family typically bind to GCC-box motifs in the promoters of JA- and ethylene-responsive genes, thereby positively or negatively regulating their expression. The GCC-box motif is sufficient for SA-mediated suppression of JA-responsive gene expression. Here, we investigated whether SA-induced ERF-type transcriptional repressors, which may compete with JA-induced ERF-type activators for binding at the GCC-box, play a role in SA/JA antagonism. We selected ERFs that are transcriptionally induced by SA and/or possess an EAR transcriptional repressor motif. Several of the 16 ERFs tested suppressed JA-dependent gene expression, as revealed by enhanced JA-induced PDF1.2 or VSP2 expression levels in the corresponding erf mutants, while others were involved in activation of these genes. However, SA could antagonize JA-induced PDF1.2 or VSP2 in all erf mutants, suggesting that the tested ERF transcriptional repressors are not required for SA/JA cross-talk. Moreover, a mutant in the co-repressor TOPLESS, that showed reduction in repression of JA signaling, still displayed SA-mediated antagonism of PDF1.2 and VSP2. Collectively, these results suggest that SA-regulated ERF transcriptional repressors are not essential for antagonism of JA-responsive gene expression by SA. We further show that de novo SA-induced protein synthesis is required for suppression of JA-induced PDF1.2, pointing to SA-stimulated production of an as yet unknown protein that suppresses JA-induced transcription.

Asunto(s)

Proteínas de Arabidopsis/metabolismo , Ciclopentanos/farmacología , Oxilipinas/farmacología , Ácido Salicílico/metabolismo , Arabidopsis/efectos de los fármacos , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Regulación de la Expresión Génica de las Plantas/genética , Reguladores del Crecimiento de las Plantas/farmacología , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética , Factores de Transcripción/genética , Factores de Transcripción/metabolismo

RESUMEN

Nasal colonization by Staphylococcus aureus is an important risk factor for the development of a nosocomial infection. Acquisition of nasal colonization by S. aureus increases mortality in hospitalized patients, but little is known about the transmission dynamics of S. aureus. To study S. aureus transmission, colonization and colonization persistence, we developed a murine transmission model. In 20 cages, 2 out of 10 mice were nasally inoculated (at 5×10(8) c.f.u. per mouse) with either meticillin-susceptible S. aureus (MSSA) (10 cages) or meticillin-resistant S. aureus (MRSA) (10 cages). On days 5, 15, 25 and 40, all mice in a cage were swabbed or sacrificed and nasal colonization and c.f.u. were determined in all 10 mice by nasal dissection or by nasal swab. Spread and subsequent stable colonization by both MSSA and MRSA from colonized to uncolonized mice within a cage was seen. At day 5, an increased number of colonized mice were observed in the MSSA group compared to the MRSA group (P = 0.003). On day 40, the mean number of c.f.u. per mouse was higher for MRSA than for MSSA (P = 0.06). Faecal-oral transmission was shown to be a possibly important transmission route in this model. These results suggest a more rapid spread of MSSA compared to MRSA. However, MRSA shows a more stable nasal colonization after a longer period of time.

Asunto(s)

Portador Sano/microbiología , Modelos Animales de Enfermedad , Resistencia a la Meticilina , Cavidad Nasal/microbiología , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/crecimiento & desarrollo , Animales , Carga Bacteriana , Portador Sano/transmisión , Femenino , Ratones , Ratones Endogámicos BALB C , Enfermedades de los Roedores/microbiología , Infecciones Estafilocócicas/transmisión , Staphylococcus aureus/efectos de los fármacos , Factores de Tiempo

RESUMEN

OBJECTIVE: To study the acquisition and cross-transmission of Staphylococcus aureus in different intensive care units (ICUs). METHODS: We performed a multicenter cohort study. Six ICUs in 6 countries participated. During a 3-month period at each ICU, all patients had nasal and perineal swab specimens obtained at ICU admission and during their stay. All S. aureus isolates that were collected were genotyped by spa typing and multilocus variable-number tandem-repeat analysis typing for cross-transmission analysis. A total of 629 patients were admitted to ICUs, and 224 of these patients were found to be colonized with S. aureus at least once during ICU stay (22% were found to be colonized with methicillin-resistant S. aureus [MRSA]). A total of 316 patients who had test results negative for S. aureus at ICU admission and had at least 1 follow-up swab sample obtained for culture were eligible for acquisition analysis. RESULTS: A total of 45 patients acquired S. aureus during ICU stay (31 acquired methicillin-susceptible S. aureus [MSSA], and 14 acquired MRSA). Several factors that were believed to affect the rate of acquisition of S. aureus were analyzed in univariate and multivariate analyses, including the amount of hand disinfectant used, colonization pressure, number of beds per nurse, antibiotic use, length of stay, and ICU setting (private room versus open ICU treatment). Greater colonization pressure and a greater number of beds per nurse correlated with a higher rate of acquisition for both MSSA and MRSA. The type of ICU setting was related to MRSA acquisition only, and the amount of hand disinfectant used was related to MSSA acquisition only. In 18 (40%) of the cases of S. aureus acquisition, cross-transmission from another patient was possible. CONCLUSIONS: Colonization pressure, the number of beds per nurse, and the treatment of all patients in private rooms correlated with the number of S. aureus acquisitions on an ICU. The amount of hand disinfectant used was correlated with the number of cases of MSSA acquisition but not with the number of cases of MRSA acquisition. The number of cases of patient-to-patient cross-transmission was comparable for MSSA and MRSA.

Asunto(s)

Infección Hospitalaria , Unidades de Cuidados Intensivos/estadística & datos numéricos , Staphylococcus aureus Resistente a Meticilina/clasificación , Infecciones Estafilocócicas , Staphylococcus aureus/aislamiento & purificación , Antibacterianos/farmacología , Estudios de Cohortes , Infección Hospitalaria/epidemiología , Infección Hospitalaria/microbiología , Infección Hospitalaria/transmisión , Farmacorresistencia Bacteriana , Europa (Continente)/epidemiología , Genotipo , Desinfección de las Manos/métodos , Humanos , Control de Infecciones/métodos , Meticilina/farmacología , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/genética , Staphylococcus aureus Resistente a Meticilina/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Prevalencia , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/transmisión , Staphylococcus aureus/clasificación , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/genética

RESUMEN

Lipid II is a crucial component in bacterial cell wall synthesis [Breukink, E., et al. (1999) Science 286, 2361-2364]. It is the target of a number of important antibiotics, which include vancomycin and nisin [Breukink, E., and de Kruijff, B. (2006) Nat. Rev. Drug Discovery 5, 321-332]. Here we show that a hybrid antibiotic that consists of vancomycin and nisin fragments is significantly more active than the separate fragments against vancomycin resistant entercocci (VRE). Three different hybrids were synthesized using click chemistry and compared. Optimal spacer lengths and connection points were predicted using computer modeling.

Asunto(s)

Antibacterianos/farmacología , Enterococcus/efectos de los fármacos , Enterococcus/fisiología , Nisina/farmacología , Resistencia a la Vancomicina/efectos de los fármacos , Vancomicina/farmacología , Antibacterianos/química , Antibacterianos/metabolismo , Combinación de Medicamentos , Pruebas de Sensibilidad Microbiana , Modelos Moleculares , Conformación Molecular , Nisina/química , Nisina/metabolismo , Uridina Difosfato Ácido N-Acetilmurámico/análogos & derivados , Uridina Difosfato Ácido N-Acetilmurámico/química , Uridina Difosfato Ácido N-Acetilmurámico/metabolismo , Vancomicina/química , Vancomicina/metabolismo

RESUMEN

Invasive group A streptococcal (GAS) disease re-emerged in The Netherlands in the late 1980s. To seek an explanation for this resurgence, the genetic compositions of 22 M1 and 19 M28 GAS strains isolated in The Netherlands between 1960s and the mid-1990s were analyzed by using a mixed-genome DNA microarray. During this four-decade period, M1 and especially M28 strains acquired prophages on at least eight occasions. All prophages carried a superantigen (speA2, speC, speK) or a streptodornase (sdaD2, sdn), both associated with invasive GAS disease. Invasive and noninvasive GAS strains did not differ in prophage acquisition, suggesting that there was an overall increase in the pathogenicity of M1 and M28 strains over the last four decades rather than emergence of hypervirulent subclones. The increased overall pathogenic potential may have contributed to the reemergence of invasive GAS disease in The Netherlands.

Asunto(s)

Antígenos Bacterianos/clasificación , Proteínas de la Membrana Bacteriana Externa/clasificación , Proteínas Portadoras/clasificación , Profagos/genética , Infecciones Estreptocócicas/epidemiología , Fagos de Streptococcus/genética , Streptococcus pyogenes/patogenicidad , Streptococcus pyogenes/virología , Desoxirribonucleasa I/genética , Humanos , Países Bajos/epidemiología , Análisis de Secuencia por Matrices de Oligonucleótidos , Reacción en Cadena de la Polimerasa , Profagos/aislamiento & purificación , Infecciones Estreptocócicas/microbiología , Fagos de Streptococcus/aislamiento & purificación , Streptococcus pyogenes/clasificación , Streptococcus pyogenes/aislamiento & purificación , Superantígenos/genética , Virulencia , Factores de Virulencia/genética

RESUMEN

Group A streptococci (GAS), or Streptococcus pyogenes, are associated with a remarkable variety of diseases, ranging from superficial infections to life-threatening diseases such as toxic-shock-like syndrome (TSS). GAS strains belonging to M types M1 and M3 are associated with TSS. This study aims to obtain insight into the gene profiles underlying different M types and disease manifestations. Genomic differences between 76 clinically well characterized GAS strains collected in The Netherlands were examined using a mixed-genome microarray. Inter-M-type genomic differences clearly outweighed intra-M-type genome variation. Phages were major contributors to observed genome diversification. We identified four novel genes, including two genes encoding fibronectin-binding-like proteins, which are highly specific to a subset of M types and thus may contribute to M-type-associated disease manifestations. All M12 strains were characterized by the unique absence of the citrate lyase complex and reduced growth under hypoxic, nutrient-deprived conditions. Furthermore, six virulence factors, including genes encoding a complement-inhibiting protein (sic), an exotoxin (speA), iron(III) binding factor, collagen binding factor (cpa), and fibrinogen binding factor (prt2-like), were unique to M1 and/or M3 strains. These virulence factors may contribute to the potential of these strains to cause TSS. Finally, in contrast to M-type-specific virulence profiles, we did not identify a common virulence profile among strains associated with TSS irrespective of their M type.

Asunto(s)

Antígenos Bacterianos/clasificación , Proteínas de la Membrana Bacteriana Externa/clasificación , Proteínas Portadoras/clasificación , Genoma Bacteriano , Análisis de Secuencia por Matrices de Oligonucleótidos/métodos , Choque Séptico/fisiopatología , Streptococcus pyogenes/clasificación , Streptococcus pyogenes/patogenicidad , Antígenos Bacterianos/genética , Antígenos Bacterianos/metabolismo , Proteínas de la Membrana Bacteriana Externa/genética , Proteínas de la Membrana Bacteriana Externa/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Electroforesis en Gel de Campo Pulsado , Perfilación de la Expresión Génica , Humanos , Procesamiento de Imagen Asistido por Computador , Choque Séptico/microbiología , Infecciones Estreptocócicas/microbiología , Infecciones Estreptocócicas/fisiopatología , Streptococcus pyogenes/genética , Streptococcus pyogenes/metabolismo , Factores de Virulencia/genética , Factores de Virulencia/metabolismo

RESUMEN

We investigated antibody responses against pneumococci of serotypes 6B, 14, and 23F in 56 children and adolescents with perinatal human immunodeficiency virus (HIV) infection who were vaccinated with 7-valent pneumococcal conjugate vaccine. Overall immune responses differed greatly between serotypes. Correlation coefficients between immunoglobulin G (IgG) measured by enzyme-linked immunosorbent assay (ELISA) and functional antibodies measured by a flow cytometry opsonophagocytosis assay (OPA) varied with serotype and time points studied. After 3 months of administering a second PCV7 dose we got the highest correlation (with significant r values of 0.754, 0.414, and 0.593 for serotypes 6B, 14, and 23F, respectively) but no significant increase in IgG concentration and OPA titers compared to the first dose. We defined a responder to a serotype included in the vaccine with two criteria: frequency of at least twofold OPA and ELISA increases for each serotype and frequency of conversion from negative to positive OPA levels. Responders varied from 43.9% to 46.3%, 28.5% to 50.0%, and 38.0% to 50.0% for serotypes 6B, 14, and 23F, respectively, depending on the response criterion. The present research highlights the importance of demonstrating vaccine immunogenicity with suitable immunological endpoints in immunocompromised patients and also the need to define how much antibody is required for protection from different serotypes, since immunogenicity differed significantly between serotypes.

Asunto(s)

Infecciones por VIH/complicaciones , Inmunoglobulina G/sangre , Infecciones Neumocócicas/prevención & control , Vacunas Neumococicas/inmunología , Adolescente , Antígenos Bacterianos/inmunología , Niño , Preescolar , Ensayo de Inmunoadsorción Enzimática , Femenino , Citometría de Flujo , Humanos , Inmunización Secundaria , Inmunoglobulina G/inmunología , Masculino , Infecciones Neumocócicas/etiología , Streptococcus pneumoniae/genética

Asunto(s)

Antioxidantes/metabolismo , Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/microbiología , Enterococcus faecalis/patogenicidad , Pseudomonas aeruginosa/patogenicidad , Especies Reactivas de Oxígeno/metabolismo , Animales , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Enterococcus faecalis/metabolismo , Genes de Helminto , Peróxido de Hidrógeno/metabolismo , Longevidad , Mutación , Pseudomonas aeruginosa/metabolismo , Receptor de Insulina/genética , Receptor de Insulina/fisiología , Superóxidos/metabolismo

RESUMEN

Recently, we reported that Streptococcus pyogenes kills Caenorhabditis elegans by the use of hydrogen peroxide (H2O2). Here we show that diverse streptococcal species cause death of C. elegans larvae in proportion to the level of H2O2 produced. H2O2 may mask the effects of other pathogenicity factors of catalase-negative bacteria in the C. elegans infection model.

Asunto(s)

Caenorhabditis elegans/efectos de los fármacos , Peróxido de Hidrógeno/toxicidad , Streptococcus/patogenicidad , Animales , Peróxido de Hidrógeno/metabolismo , Streptococcus/metabolismo

RESUMEN

Oligosaccharide (OS)-protein conjugates are promising candidate vaccines against encapsulated bacteria, such as Haemophilus influenzae, Neisseria meningitidis, and Streptococcus pneumoniae. Although the effects of several variables such as OS chain length and protein carrier have been studied, little is known about the influence of adjuvants on the immunogenicity of OS-protein conjugates. In this study, a minimal protective trisaccharide epitope of Streptococcus pneumoniae type 3 conjugated to the cross-reacting material of diphtheria toxin was used for immunization of BALB/c mice in the presence of different adjuvants. Subsequently, half of the mice received a booster immunization with conjugate alone. Independent of the use and type of adjuvant, all mice produced long-lasting anti-polysaccharide type 3 (PS3) antibody levels, which provided full protection against challenge with pneumococcal type 3 bacteria. All adjuvants tested increased the anti-PS3 antibody levels and opsonic capacities as measured by an enzyme-linked immunosorbent assay and an in vitro phagocytosis assay. The use of QuilA or a combination of the adjuvants CpG and dimethyl dioctadecyl ammonium bromide resulted in the highest phagocytic capacities and the highest levels of Th1-related immunoglobulin G (IgG) subclasses. Phagocytic capacity correlated strongly with Th1-associated IgG2a and IgG2b levels, to a lesser extent with Th2-associated IgG1 levels, and weakly with thiocyanate elution as a measure of avidity. Thus, the improved immunogenicity of OS-protein conjugates was most pronounced for Th1-directing adjuvants.

Asunto(s)

Adyuvantes Inmunológicos/farmacología , Toxoide Diftérico/inmunología , Vacunas Neumococicas/inmunología , Polisacáridos Bacterianos/inmunología , Células TH1/inmunología , Vacunas Conjugadas/inmunología , Animales , Anticuerpos Antibacterianos/sangre , Especificidad de Anticuerpos , Femenino , Inmunización , Inmunización Secundaria , Inmunoglobulina G/sangre , Inmunoglobulina G/clasificación , Ratones , Ratones Endogámicos BALB C , Proteínas Opsoninas , Fagocitosis , Infecciones Neumocócicas/inmunología , Infecciones Neumocócicas/prevención & control , Vacunas Neumococicas/administración & dosificación , Streptococcus pneumoniae/clasificación , Streptococcus pneumoniae/inmunología , Vacunas Conjugadas/administración & dosificación

RESUMEN

Acute rheumatic fever is a serious autoimmune sequel of Streptococcus pyogenes infection. This study shows that serotype M3 and M18 S. pyogenes isolated during outbreaks of rheumatic fever have the unique capability to bind and aggregate human basement membrane collagen type IV. M3 protein is identified as collagen-binding factor of M3 streptococci, whereas M18 isolates bind collagen through a hyaluronic acid capsule, revealing a novel function for M3 protein and capsule. Following in vivo mouse passage, conversion of a nonencapsulated and collagen-binding negative M1 S. pyogenes into an encapsulated, collagen-binding strain further supports the crucial role of capsule in mediating collagen binding. Collagen binding represents a novel colonization mechanism, as it is demonstrated that S. pyogenes bind to collagen matrix in vitro and in vivo. Moreover, immunization of mice with purified recombinant M3 protein led to the generation of anti-collagen type IV antibodies. Finally, sera from acute rheumatic fever patients had significantly increased titers of anti-collagen type IV antibodies as compared with healthy controls. These findings may suggest a link between the potential of rheumatogenic S. pyogenes isolates to bind collagen, and the presence of collagen-reactive autoantibodies in the serum of rheumatic fever patients, which may form a basis for post-streptococcal rheumatic disease. These anti-collagen antibodies may form a basis for poststreptococcal rheumatic disease.

Asunto(s)

Antígenos Bacterianos , Colágeno Tipo IV/inmunología , Fiebre Reumática/inmunología , Fiebre Reumática/microbiología , Streptococcus pyogenes/patogenicidad , Animales , Autoanticuerpos/sangre , Proteínas de la Membrana Bacteriana Externa/genética , Proteínas de la Membrana Bacteriana Externa/inmunología , Secuencia de Bases , Proteínas Portadoras/genética , Proteínas Portadoras/inmunología , Estudios de Casos y Controles , Colágeno Tipo IV/ultraestructura , ADN Bacteriano/genética , Femenino , Humanos , Inmunización , Técnicas In Vitro , Ratones , Ratones Endogámicos BALB C , Microscopía Electrónica de Rastreo , Proteínas Recombinantes/genética , Proteínas Recombinantes/inmunología , Streptococcus pyogenes/genética , Streptococcus pyogenes/inmunología

RESUMEN

This study aimed to characterize matrix assembly mechanisms on the surface of the human pathogen Streptococcus pyogenes. Among 125 S. pyogenes isolates, 61% were able to recruit collagen type IV via surface-bound fibronectin. Streptococcus gordonii expressing the fibronectin-binding repeat domain of S. pyogenes SfbI protein was equally potent in recruiting collagen, indicating that this domain was sufficient to promote fibronectin-mediated collagen recruitment. Electron microscopic analysis of streptococci revealed that fibronectin-mediated collagen recruitment led to matrix deposition on and between streptococcal cells, which induced the formation of large bacterial aggregates. Furthermore, collagen-recruiting streptococci were able to colonize collagen fibres and were protected from adhering to human polymorphonuclear cells in the presence of opsonizing antibodies. Fibronectin-mediated collagen recruitment thus represents a novel aggregation, colonization and immune evasion mechanism of S. pyogenes.

Asunto(s)

Adhesinas Bacterianas , Adhesión Bacteriana , Proteínas Bacterianas/metabolismo , Proteínas Portadoras/metabolismo , Colágeno/metabolismo , Fibronectinas/metabolismo , Streptococcus pyogenes/patogenicidad , Animales , Proteínas Bacterianas/química , Proteínas Portadoras/química , Línea Celular , Humanos , Ratones , Microscopía Electrónica , Fagocitosis , Streptococcus pyogenes/inmunología , Streptococcus pyogenes/ultraestructura