The type VII secretion system of <i>Staphylococcus aureus</i> secretes a nuclease toxin that targets competitor bacteria

The type VII protein secretion system (T7SS) plays a critical role in the virulence of human pathogens including Mycobacterium tuberculosis and Staphylococcus aureus. Here we report that the S. aureus T7SS secretes a large nuclease toxin, EsaD. The toxic activity of EsaD is neutralised during its biosynthesis through complex formation with an antitoxin, EsaG, which binds to its C-terminal nuclease domain. The secretion of EsaD is dependent upon a further accessory protein, EsaE, that does not interact with the nuclease domain, but instead binds to the EsaD N-terminal region. EsaE has a dual cytoplasmic/membrane localization and membrane-bound EsaE interacts with the T7SS secretion ATPase, EssC, implicating EsaE in targeting the EsaDG complex to the secretion apparatus. EsaD and EsaE are co-secreted whereas EsaG is found only in the cytoplasm and may be stripped off during the secretion process. Strain variants of S. aureus that lack esaD encode at least two copies of EsaG-like proteins most likely to protect themselves from the toxic activity of EsaD secreted by esaD(+) strains. In support of this, a strain overproducing EsaD elicits significant growth inhibition against a sensitive strain. We conclude that T7SSs may play unexpected and key roles in bacterial competitiveness

The Enigmatic Esx Proteins:Looking Beyond Mycobacteria

Bacteria export proteins across membranes using a range of transport machineries. Type VII secretion systems (T7SSs), originally described in mycobacteria, are now known to be widespread across diverse bacterial phyla. Recent studies have characterized secretion components and mechanisms of type VII secretion in pathogenic and environmental bacteria. A variety of functions have been attributed to T7SS substrates, including interactions with eukaryotes and with other bacteria. Here, we evaluate the growing body of knowledge on T7SSs, with focus on the nonmycobacterial systems, reviewing their phylogenetic distribution, structure and function in diverse settings

Fenton sterilization of bacillus spores

This investigation evaluated the extent of Bacillus subtilis spore inactivation using Fenton reagent. The experimenter used B. subtilis spores as a surrogate for Bacillus anthracis to evaluate use of oxidation hydroxyl radicals through a cyclic reaction between divalent iron and hydrogen peroxide. This Major Qualifying Project (MQP) determined the concentrations and exposure period of Fenton chemicals that inactivate approximately 99 percent of a spore population

Community-Engaged Modeling of Geographic and Demographic Patterns of Multiple Public Health Risk Factors

Many health risk factors are intervention targets within communities, but information regarding high-risk subpopulations is rarely available at a geographic resolution that is relevant for community-scale interventions. Researchers and community partners in New Bedford, Massachusetts (USA) collaboratively identified high-priority behaviors and health outcomes of interest available in the Behavioral Risk Factor Surveillance System (BRFSS). We developed multivariable regression models from the BRFSS explaining variability in exercise, fruit and vegetable consumption, body mass index, and diabetes prevalence as a function of demographic and behavioral characteristics, and linked these models with population microdata developed using spatial microsimulation to characterize high-risk populations and locations. Individuals with lower income and educational attainment had lower rates of multiple health-promoting behaviors (e.g., fruit and vegetable consumption and exercise) and higher rates of self-reported diabetes. Our models in combination with the simulated population microdata identified census tracts with an elevated percentage of high-risk subpopulations, information community partners can use to prioritize funding and intervention programs. Multi-stressor modeling using data from public databases and microsimulation methods for characterizing high-resolution spatial patterns of population attributes, coupled with strong community partner engagement, can provide significant insight for intervention. Our methodology is transferrable to other communities

CCTIS: An Expert Transactions Processing System

CCTIS, the Cargo Container Targeting Information System, was developed for the U.S. Customs Service to help monitor and control goods imported by ship. As an expert system, CCTIS has a combination of features which make it of interest to the applied A.I. community. First of all, CCTIS interacts with a large database --- but unlike most data-oriented expert systems CCTIS is used in a transactions-oriented environment and needs the speed of such a system. Secondly, there exists no single cognitive model for the domain of import control, and it is unlikely that such a model can be developed in the near future. To address this problem CCTIS includes the ability for users to weigh and parameterize rules. And thirdly, the information CCTIS uses is often derived from free text of low quality that must be corrected and analyzed through natural language analysis techniques. The system uses a logic-based approach to solving these problems, defining explicit algorithms to extract data from text, ..

The private sector and improving human capital in Southeast Asia

This project explored methods of improving Thailand's human capital during its demographic transition. Using data from the College of Population Studies at Chulalongkorn University we examined regional human capital development. The team interviewed representatives of Thai and multinational corporations on regional cooperation and workforce competitiveness, productivity and training. These interviews, along with relevant literature, shaped our recommendations for educational curricula, training programs, resource pooling in ASEAN, and government policies and economic growth