Nanoparticles: Properties, applications and toxicities

Biofilms are complex communities of microorganisms attached to surfaces or associated with interfaces. Despite the focus of modern microbiology research on pure culture, planktonic (free-swimming) bacteria, it is now widely recognized that most bacteria found in natural, clinical, and industrial settings persist in association with surfaces. Furthermore, these microbial communities are often composed of multiple species that interact with each other and their environment. The determination of biofilm architecture, particularly the spatial arrangement of microcolonies (clusters of cells) relative to one another, has profound implications for the function of these complex communities. Numerous new experimental approaches and methodologies have been developed in order to explore metabolic interactions, phylogenetic groupings, and competition among members of the biofilm. To complement this broad view of biofilm ecology, individual organisms have been studied using molecular genetics in order to identify the genes required for biofilm development and to dissect the regulatory pathways that control the plankton-to-biofilm transition. These molecular genetic studies have led to the emergence of the concept of biofilm formation as a novel system for the study of bacterial development. The recent explosion in the field of biofilm research has led to exciting progress in the development of new technologies for studying these communities, advanced our understanding of the ecological significance of surface-attached bacteria, and provided new insights into the molecular genetic basis of biofilm development.

Microbial Biofilms: from Ecology to Molecular Genetics

BET Bromodomain Inhibition as a Therapeutic Strategy to Target c-Myc

Viruses are the most common biological agents in the sea, typically numbering ten billion per litre. They probably infect all organisms, can undergo rapid decay and replenishment, and influence many biogeochemical and ecological processes, including nutrient cycling, system respiration, particle size-distributions and sinking rates, bacterial and algal biodiversity and species distributions, algal bloom control, dimethyl sulphide formation and genetic transfer. Newly developed fluorescence and molecular techniques leave the field poised to make significant advances towards evaluating and quantifying such effects.

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Marine viruses and their biogeochemical and ecological effects

The discovery that viruses may be the most abundant organisms in natural waters, surpassing the number of bacteria by an order of magnitude, has inspired a resurgence of interest in viruses in the aquatic environment. Surprisingly little was known of the interaction of viruses and their hosts in nature. In the decade since the reports of extraordinarily large virus populations were published, enumeration of viruses in aquatic environments has demonstrated that the virioplankton are dynamic components of the plankton, changing dramatically in number with geographical location and season. The evidence to date suggests that virioplankton communities are composed principally of bacteriophages and, to a lesser extent, eukaryotic algal viruses. The influence of viral infection and lysis on bacterial and phytoplankton host communities was measurable after new methods were developed and prior knowledge of bacteriophage biology was incorporated into concepts of parasite and host community interactions. The new methods have yielded data showing that viral infection can have a significant impact on bacteria and unicellular algae populations and supporting the hypothesis that viruses play a significant role in microbial food webs. Besides predation limiting bacteria and phytoplankton populations, the specific nature of virus-host interaction raises the intriguing possibility that viral infection influences the structure and diversity of aquatic microbial communities. Novel applications of molecular genetic techniques have provided good evidence that viral infection can significantly influence the composition and diversity of aquatic microbial communities.

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Virioplankton: viruses in aquatic ecosystems

http://bioinformatica.uab.es/biocomputacio/treballs02-03/RBurgos/dades/Articulos/Fieldaplication..pdf

Field applications of genetically engineered microorganisms for bioremediation processes

Disclosed are bioluminescent bioreporter integrated circuit devices that detect selected analytes in fluids when implanted in the body of an animal. The device comprises a bioreporter that has been genetically engineered to contain a nucleic acid segment that comprises a cis-activating response element that is responsive to the selected substance operably linked to a gene encoding a bioluminescent reporter polypeptide. In preferred embodiments, the target analyte is glucose, glucagons, or insulin. Exposure of the bioreporter to the target substance causes the response element to up-regulate the nucleic acid sequence encoding the reporter polypeptide to produce a luminescent response that is detected and quantitated. In illustrative embodiments, the bioreporter device is encapsulated on an integrated circuit that is capable of detecting the emitted light, processing the resultant signal, and then remotely reporting the results. Also disclosed are controlled drug delivery systems capable of being directly or indirectly controlled by the detection device that provide drugs such as insulin to the animal in reponse to the amount of target analyte present in the body fluids.

In vivo biosensor apparatus and method of use

In vivo bioluminescent imaging (BLI) is increasingly being utilized as a method for modern biological research. This process, which involves the noninvasive interrogation of living animals using light emitted from luciferase-expressing bioreporter cells, has been applied to study a wide range of biomolecular functions such as gene function, drug discovery and development, cellular trafficking, protein-protein interactions, and especially tumorigenesis, cancer treatment, and disease progression. This article will review the various bioreporter/biosensor integrations of BLI and discuss how BLI is being applied towards a new visual understanding of biological processes within the living organism.

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In vivo bioluminescent imaging (BLI): noninvasive visualization and interrogation of biological processes in living animals.

Pseudomonas fluorescens HK44 represents the first genetically engineered microorganism approved for field testing in the United States for bioremediation purposes. Strain HK44 harbors an introduced lux gene fused within a naphthalene degradative pathway, thereby allowing this recombinant microbe to bioluminesce as it degrades specific polyaromatic hydrocarbons such as naphthalene. The bioremediation process can therefore be monitored by the detection of light. P. fluorescens HK44 was inoculated into the vadose zone of intermediate-scale, semicontained soil lysimeters contaminated with naphthalene, anthracene, and phenanthrene, and the population dynamics were followed over an approximate 2-year period in order to assess the long-term efficacy of using strain HK44 for monitoring and controlling bioremediation processes. Results showed that P. fluorescens HK44 was capable of surviving initial inoculation into both hydrocarbon contaminated and uncontaminated soils and was recoverable from these soils 660 day...

Controlled Field Release of a Bioluminescent Genetically Engineered Microorganism for Bioremediation Process Monitoring and Control

An estrogen-inducible bacterial lux-based bioluminescent reporter was developed in Saccharomyces cerevisiae for applications in chemical sensing and environmental assessment of estrogen disruptor activity. The strain, designated S. cerevisiae BLYES, was constructed by inserting tandem estrogen response elements between divergent yeast promoters GPD and ADH1 on pUTK401 (formerly pUA12B7) that constitutively express luxA and luxB to create pUTK407. Cotransformation of this plasmid with a second plasmid (pUTK404) containing the genes required for aldehyde synthesis (luxCDE) and FMN reduction (frp) yielded a bioluminescent bioreporter responsive to estrogen-disrupting compounds. For validation purposes, results with strain BLYES were compared to the colorimetric-based estrogenic assay that uses the yeast lacZ reporter strain (YES). Strains BLYES and YES were exposed to 17-estradiol over the concentration range of 1.2 10 8 through 5.6 10 12 M. Calculated 50% effective concentration values from the colorimetric and bioluminescence assays (n 7) were similar at (4.4 1.1) 10 10 and (2.4 1.0) 10 10 M, respectively. The lower and upper limits of detection for each assay were also similar and were approximately 4.5 10 11 to 2.8 10 9 M. Bioluminescence was observed in as little as 1 h and reached its maximum in 6 h. In comparison, the YES assay required a minimum of 3 days for results. Strain BLYES fills the niche for rapid, high-throughput screening of estrogenic compounds and has the ability to be used for remote, near-real-time monitoring of estrogendisrupting chemicals in the environment.

https://cfpub.epa.gov/ncer_abstracts/index.cfm/fuseaction/display.files/fileID/13308

Steven Ripp

Papers

Field applications of genetically engineered microorganisms for bioremediation processes

In vivo biosensor apparatus and method of use

In vivo bioluminescent imaging (BLI): noninvasive visualization and interrogation of biological processes in living animals.

Controlled Field Release of a Bioluminescent Genetically Engineered Microorganism for Bioremediation Process Monitoring and Control

Use of Saccharomyces cerevisiae BLYES expressing bacterial bioluminescence for rapid, sensitive detection of estrogenic compounds.