Development of an Accurate Toxicity Assay Using Genetically Engineered Bioluminescent Bacteria

Methods of developing and improving toxicity assays using genetically engineered bioluminescent bacteria PM6 and Shk1 were investigated. The EC50 values for three metals (zinc, copper, and lead) were determined using these two strains and were compared with the EC50 values calculated from the Microtox® assay, published inhibition to activated sludge specific oxygen uptake rate (SOUR) data (Madonii et al., 1999), and published EC50 values from Microtox® for the same compounds (Kaiser and Devillers, 1994). This was done to evaluate the effectiveness of using strains PM6 and Shk1 to predict toxic effects to activated sludge as indicated by respiration inhibition. A number of factors affecting toxicity assays were examined including temperature control, cell storage method (lyophilization and storage temperature), activation time, and mixing prior to luminescence measurement. A toxicity testing protocol developed by Lajoie et al. (2002) was used and adapted to this study. Based on the results of these experiments, it was concluded that toxicity assays using PM6 and Shk1 provide EC50 values closer to respiration inhibition EC50 values than Microtox®

Portable light detectors for bioluminescence biosensing applications: A comprehensive review from the analytical chemist's perspective

Bioluminescence, that is the emission of light in living organisms, has been extensively explored and applied for diverse bioanalytical applications, spanning from molecular imaging to biosensing. The unprecedented technological evolution of portable light detectors opened new possibilities to implement bioluminescence detection into miniaturized devices. We are witnessing a number of applications, including DNA sequencing, reporter gene assays, DNA amplification for point-of care and point-of need analyses relying on BL. Several photon detectors are currently available for measuring low light emission, such as photomultiplier tubes (PMT), charge-coupled devices (CCD), complementary metal oxide semiconductors (CMOS), single photon avalanche diodes (SPADs), silicon photomultipliers (SiPMs) and smartphone-integrated CMOS. Each technology has pros and cons and several issues, such as temperature dependence of the instrumental specific noise, the power supply, imaging capability and ease of integration, should be considered in the selection of the most appropriate detector for the selected BL application

Florida marine biotechnology: research, development and training capabilities to advance science and commerce

The level of activity and interest in “marine biotechnology” among Florida university faculty and allied laboratory scientists is reported in this document. The information will be used to (1) promote networking and collaboration in research and education, (2) inform industry of possible academic partners, (3) identify contacts interested in potential new sources of funding, and (4) assist development of funding for a statewide marine biotechnology research, training and development program. This document is the first of its kind. Institutions of higher learning were given the opportunity to contribute both an overview of campus capabilities and individual faculty Expressions of Scientific Interest. They are listed in the table of contents. (104pp.

Biosensor technology: applications in microbial toxicology

This work describes the development of mediated amperometric biosensors that are able to monitor the metabolic activity of both single and mixed microbial populations, with applications in toxicity assessment and wastewater treatment plant protection. Biosensor systems have been constructed incorporating either the single-species eubacteria Escherichia coli or Pseudomonas putida, Bioseed®, or a mixture of activated sludge organisms from wastewater treatment plants, as the sensing components immobilised on disposable screen printed electrodes in stirred reaction vials. The biosensor approach is generic allowing for a wide range of microbial cell types to be employed. Appropriate bacterial species can be selected for specific sensor applications in order to confer validity and relevance to the test, hence the biosensor can be tailor-made to assess the toxicity in a particular environment and provide diagnostically valid and relevant results. The biosensors have been used to assess the toxicity of a standard toxicant and toxicant formulations and in blind testing of a range of industrial effluents, in parallel with a number of bioassays including Microtox® and activated sludge respiration inhibition. The biosensor results generally show significant correlation to the appropriate conventional toxicity tests. In this study, an activated sludge based biosensor assay was developed and used to assess the toxicity of industrial process and site effluents with the specific purpose of wastewater treatment plant protection. Data generated compared significantly with those from an activated sludge respiration inhibition test, with added advantages of rapidity, safety and ease of use

Aerospace medicine and biology: A cumulative index to the continuing bibliography of the 1973 issues

A cumulative index to the abstracts contained in Supplements 112 through 123 of Aerospace Medicine and Biology A Continuing Bibliography is presented. It includes three indexes: subject, personal author, and corporate source

Rational Design of Metal-Organic Frameworks (MOFs)-based Functional Materials Towards Better Air Quality

Air pollution is a major threat to environmental safety and public health. Volatile organic compounds (VOCs), particulate matter (PM), and airborne microorganisms are three typical air pollutants. Conventional strategies to prevent and mitigate air pollution have been employed, which, however, are generally passive. For instance, VOC sensing through solid-state devices is a conventional approach, which, however, is not capable of capturing and removing VOCs. On the other hand, air filters and face masks are useful equipment to protect people from inhaling PM and airborne microorganisms. But most commercial filters can only capture them on the surfaces, which may cause secondary contamination under high airflow rates. This is particularly true for airborne pathogens, such as bacteria, fungi, and viruses, which can survive on the filter surface for hours or even days, creating a potential risk of biosafety issues. Therefore, it is highly desired to develop advanced materials to solve the above air issues actively. Metal-organic frameworks (MOFs), a novel porous crystalline material, have received considerable attention over the past decades because of their exceptional physical and chemical properties, including high porosity, huge specific surface area, structure robustness, and chemistry flexibility and diversity. These intriguing properties make MOFs an excellent candidate to combat the above air contamination. Numerous attempts have been reported to improve the performance of MOFs. However, the challenges remain in MOF design and its applications because of the complex interactions between MOFs and target pollutants. The objective of this dissertation is to rationally design MOFs-based functional materials for efficient air quality control. This dissertation also aims to explore the quantitative interactions between the target air pollutants and the MOF-based materials by using advanced instruments, which generate new knowledge and understanding for future materials designed for better air quality. The dissertation is divided into two major parts: VOC (H2S as a model) detection and airborne bacterial inactivation. In Chapters 2 and 3, a novel bimetallic MOF (i.e., Al/Fe-MIL-53-NH2) was developed to significantly improve its sensing performance towards a representative VOC of H2S molecules based on the fluorescence “turn-on” effect. Beyond the improved performance of MOF-based materials, fundamental understandings of interactions between H2S and MOF-based materials were also discussed. More specifically, the mechanisms of H2S detection were successfully unraveled, where nitro-MOFs (e.g., Al-MIL-53-NO2) were used to achieve quantitative fluorescence sensing. The new insights based on the investigations in this dissertation are completely different from what has been reported in previous studies. The results showed that it is the free BDC-NH2 (2-aminobenzene-1,4-dicarboxylic acid) in the solution rather than the formation of Al-MIL-53-NH2 that caused the fluorescence enhancement. In Chapters 4 and 5, novel antimicrobial materials have been designed by coating a quaternary ammonium compound (QAC) polymer, that is poly[2-(dimethyl decyl ammonium) ethyl methacrylate] (PQDMAEMA), onto the surface of various MOF-based materials (e.g., UiO-66-NH2 (zirconium-based), g-C3N4/MIL-125-NH2 (titanium-based)) to form active composites for airborne bacterial inactivation. These rationally designed MOF composites demonstrated great antibacterial activities where electrostatic contact-killing and photogenerated reactive oxygen species (ROS) are utilized for efficient disinfection. In-depth investigations on the biointerface were carried out with several advanced techniques, such as the Zeta-potential analyzer, fluorescence laser confocal microscope (CLSM), and atomic force microscope (AFM). The results showed that the adhesion of bacterial cells towards the photocatalyst surface leads to significantly enhanced photocatalytic bactericidal efficiencies. The work from this dissertation is expected to broaden the applications of MOF-based materials and advance the understanding of the interactions between MOFs and pollutants from the molecular level, which should have a significant impact on the rational design of MOF-based materials for air quality control and improvement

Biosensors for Environmental Monitoring

Real-time and reliable detection of molecular compounds and bacteria is essential in modern environmental monitoring. For rapid analyses, biosensing devices combining high selectivity of biomolecular recognition and sensitivity of modern signal-detection technologies offer a promising platform. Biosensors allow rapid on-site detection of pollutants and provide potential for better understanding of the environmental processes, including the fate and transport of contaminants.This book, including 12 chapters from 37 authors, introduces different biosensor-based technologies applied for environmental analyses