Kinetic pathway of 40S ribosomal subunit recruitment to hepatitis C virus internal ribosome entry site.
Proceedings of the National Academy of Sciences of the United States of America
2015; 112 (2): 319-325
Three-Dimensional Human Skin Models to Understand Staphylococcus aureus Skin Colonization and Infection.
Frontiers in immunology
2014; 5: 41-?
Translation initiation can occur by multiple pathways. To delineate these pathways by single-molecule methods, fluorescently labeled ribosomal subunits are required. Here, we labeled human 40S ribosomal subunits with a fluorescent SNAP-tag at ribosomal protein eS25 (RPS25). The resulting ribosomal subunits could be specifically labeled in living cells and in vitro. Using single-molecule Förster resonance energy transfer (FRET) between RPS25 and domain II of the hepatitis C virus (HCV) internal ribosome entry site (IRES), we measured the rates of 40S subunit arrival to the HCV IRES. Our data support a single-step model of HCV IRES recruitment to 40S subunits, irreversible on the initiation time scale. We furthermore demonstrated that after binding, the 40S:HCV IRES complex is conformationally dynamic, undergoing slow large-scale rearrangements. Addition of translation extracts suppresses these fluctuations, funneling the complex into a single conformation on the 80S assembly pathway. These findings show that 40S:HCV IRES complex formation is accompanied by dynamic conformational rearrangements that may be modulated by initiation factors.
View details for DOI 10.1073/pnas.1421328111
View details for PubMedID 25516984
Interferon-? Therapy Prolongs Survival in Rhesus Macaque Models of Ebola and Marburg Hemorrhagic Fever.
The Journal of infectious diseases
Staphylococcus aureus is both a major bacterial pathogen as well as a common member of the human skin microbiota. Due to its widespread prevalence as an asymptomatic skin colonizer and its importance as a source of skin and soft tissue infections, an improved understanding of how S. aureus attaches to, grows within, and breaches the stratified layers of the epidermis is of critical importance. Three-dimensional organotypic human skin culture models are informative and tractable experimental systems for future investigations of the interactions between S. aureus and the multi-faceted skin tissue. We propose that S. aureus virulence factors, primarily appreciated for their role in pathogenesis of invasive infections, play alternative roles in promoting asymptomatic bacterial growth within the skin. Experimental manipulations of these cultures will provide insight into the many poorly understood molecular interactions occurring at the interface between S. aureus and stratified human skin tissue.
View details for DOI 10.3389/fimmu.2014.00041
View details for PubMedID 24567733
INFLUENZA VACCINE PRODUCTION FOR THE US MARKET
BIOSECURITY AND BIOTERRORISM-BIODEFENSE STRATEGY PRACTICE AND SCIENCE
2009; 7 (3): 259-263
Factors affecting survival of bacteriophage on tomato leaf surfaces
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
2007; 73 (6): 1704-1711
There is a clear need for novel, effective therapeutic approaches to hemorrhagic fever due to filoviruses. Ebola virus hemorrhagic fever is associated with robust interferon (IFN)-? production, with plasma concentrations of IFN-? that greatly (60- to 100-fold) exceed those seen in other viral infections, but little IFN-? production. While all of the type I IFNs signal through the same receptor complex, both quantitative and qualitative differences in biological activity are observed after stimulation of the receptor complex with different type I IFNs. Taken together, this suggested potential for IFN-? therapy in filovirus infection. Here we show that early postexposure treatment with IFN-? significantly increased survival time of rhesus macaques infected with a lethal dose of Ebola virus, although it failed to alter mortality. Early treatment with IFN-? also significantly increased survival time after Marburg virus infection. IFN-? may have promise as an adjunctive postexposure therapy in filovirus infection.
View details for PubMedID 23255566
The ability of bacteriophage to persist in the phyllosphere for extended periods is limited by many factors, including sunlight irradiation, especially in the UV zone, temperature, desiccation, and exposure to copper bactericides. The effects of these factors on persistence of phage and formulated phage (phage mixed with skim milk) were evaluated. In field studies, copper caused significant phage reduction if applied on the day of phage application but not if applied 4 or 7 days in advance. Sunlight UV was evaluated for detrimental effects on phage survival on tomato foliage in the field. Phage was applied in the early morning, midmorning, early afternoon, and late evening, while UVA plus UVB irradiation and phage populations were monitored. The intensity of UV irradiation positively correlated with phage population decline. The protective formulation reduced the UV effect. In order to demonstrate direct effects of UV, phage suspensions were exposed to UV irradiation and assayed for effectiveness against bacterial spot of tomato. UV significantly reduced phage ability to control bacterial spot. Ambient temperature had a pronounced effect on nonformulated phage but not on formulated phages. The effects of desiccation and fluorescent light illumination on phage were investigated. Desiccation caused a significant but only slight reduction in phage populations after 60 days, whereas fluorescent light eliminated phages within 2 weeks. The protective formulation eliminated the reduction caused by both of these factors. Phage persistence was dramatically affected by UV, while the other factors had less pronounced effects. Formulated phage reduced deleterious effects of the studied environmental factors.
View details for DOI 10.1128/AEM.02118-06
View details for Web of Science ID 000245156800003
View details for PubMedID 17259361