Dynamac Inc.

Cincinnati, OH, United States

Dynamac Inc.

Cincinnati, OH, United States
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Lu J.,Us Epa National Exposure Research Laboratory | Struewing I.,Dynamac Inc. | Buse H.Y.,Dynamac Inc. | Kou J.,ORISE Postdoctoral Fellow at EPA | And 3 more authors.
Applied and Environmental Microbiology | Year: 2013

Copper ions are an effective antimicrobial agent used to control Legionnaires' disease and Pontiac fever arising from institutional drinking water systems. Here, we present data on an alternative bactericidal agent, copper oxide nanoparticles (CuONPs), and its efficacy on Legionella pneumophila. In broth cultures, the CuO-NPs caused growth inhibition, which appeared to be concentration and exposure time dependent. The transcriptomic response of L. pneumophila to CuO-NP exposure was investigated by using a whole-genome microarray. The expression of genes involved in metabolism, transcription, translation, DNA replication and repair, and unknown/hypothetical proteins was significantly affected by exposure to CuO-NPs. In addition, expression of 21 virulence genes was also affected by exposure to CuO-NP and further evaluated by quantitative reverse transcription-PCR (qRT-PCR). Some virulence gene responses occurred immediately and transiently after addition of CuO-NPs to the cells and faded rapidly (icmV, icmW, lepA), while expression of other genes increased within 6 h (ceg29, legLC8, legP, lem19, lem24, lpg1689, and rtxA), 12 h (cegC1, dotA, enhC, htpX, icmE, pvcA, and sidF), and 24 h (legP, lem19, and ceg19), but for most of the genes tested, expression was reduced after 24 h of exposure. Genes like ceg29 and rtxA appeared to be the most responsive to CuO-NP exposures and along with other genes identified in this study may prove useful to monitor and manage the impact of drinking water disinfection on L. pneumophila. © 2013, American Society for Microbiology.


Ware M.W.,U.S. Environmental Protection Agency | Augustine S.A.J.,U.S. Environmental Protection Agency | Hayes S.L.,U.S. Environmental Protection Agency | Erisman D.O.,U.S. Environmental Protection Agency | And 6 more authors.
Water Quality Technology Conference and Exposition 2010 | Year: 2010

Methods used to determine Toxoplasma gondii oocyst infectivity have relied primarily on immunocompetent animal bioassays. In this study, three alternative assays were developed and used to evaluate the disinfection of T. gondii oocysts by UV irradiation; two of these assays were then used to evaluate several common laboratory chemical disinfectants. The three approaches were: quantitative reverse-transcriptase real-time PCR assay (RT-qPCR), in vitro T. gondii oocyst plaque assay (TOP-assay), and severely compromised immunodeficient (SCID) mouse bioassay. Our results show that the RT-qPCR assay can not be used to determine oocyst inactivation. In contrast, the TOP-assay and/or the SCID mouse bioassay proved very effective and sensitive at quantifying inactivation efficacies of chemical or UV treatments evaluated in this study. The results showed that at least 3-log10 inactivation is achieved by exposure to 10% bleach, 10% formalin, or ≥15 mJ/cm2 UV irradiation. 2010 © American Water Works Association WQTC Conference Proceedings. All Rights Reserved.


Lu J.,Us Epa National Exposure Research Laboratory | Struewing I.,Dynamac Inc. | Yelton S.,Dynamac Inc. | Ashbolt N.,University of Alberta
Journal of Applied Microbiology | Year: 2015

Aims: To examine the occurrence and quantity of potential pathogens and an indicator of microbial contamination in the sediments of municipal drinking water storage tanks (MDWSTs), given the absence of such data across the United States. Methods and Results: Sediment samples (87 MDWST) from eighteen locations across ten states of the United States were collected and assayed by qPCR for a range of potential enteric and opportunistic microbial pathogens and a sewage-associated Bacteroides marker. Potential opportunistic pathogens dominated, with the highest detection of occurrence (per cent positive detection; average cell equivalence (CE)) being Mycobacterium spp. (88·9%; 6·7 ± 8·5 × 104 CE g-1), followed by Legionella spp. (66·7%; 5·2 ± 5·9 × 103 CE g-1), Pseudomonas aeruginosa (22·2%; 250 ± 880 CE g-1) and Acanthamoeba spp. (38·9%; 53 ± 70 CE g-1), with no detected Naegleria fowleri. Most enteric pathogens (Campylobacter jejuni, Escherichia coli 0157:H7, Salmonella enterica, Cryptosporidium parvum and Giardia duodenalis) were not detected, except for a trace signal for Campylobacter spp. There was significant correlation between the qPCR signals of Legionella spp. and Acanthamoeba spp. (R2 = 0·61, n = 87, P = 0·0001). Diverse Legionella spp. including Leg. pneumophila, Leg. pneumophila sg1 and Leg. anisa were identified, each of which might cause legionellosis. Conclusions: These results imply that potential opportunistic pathogens are common within MDWST sediments and could act as a source of microbial contamination, but need downstream growth to be of potential concern. Significance and Impact of the Study: The results imply that opportunistic pathogen risks may need to be managed by regular tank cleaning or other management practices. © 2015 The Society for Applied Microbiology.


Rask J.,Dynamac Inc. | Heldmann J.,NASA | Smith H.,Utah State University | Battler M.,University of Western Ontario | McKay C.,NASA
Special Paper of the Geological Society of America | Year: 2011

A comprehensive fi eld training curriculum was developed and tested during the 2006, 2008, 2009, and 2010 National Aeronautics and Space Administration (NASA) Spaceward Bound missions at the Mars Desert Research Station (MDRS). The curriculum was developed to train teachers and students in fundamentals of Moon and Mars analog station operations, logistics, fi eld work, and scientifi c investigation. The curriculum is composed of background content, directions, lesson plans, suggestions, protocols, images, diagrams, fi gures, checklists, worksheets, experiments, fi eld missions, and references. To date, 48 individuals have participated in Spaceward Bound missions at MDRS, and 18 have successfully tested the curriculum. Based on our analysis and student feedback, we conclude that the Spaceward Bound curriculum is highly useful in training teachers and students in aspects of astrobiology, fi eld science, and Mars exploration, and that MDRS is an ideal location for its use. © 2011 The Geological Society of America.


PubMed | University of Alberta, Dynamac Inc. and Us Epa National Exposure Research Laboratory
Type: Journal Article | Journal: Journal of applied microbiology | Year: 2015

To examine the occurrence and quantity of potential pathogens and an indicator of microbial contamination in the sediments of municipal drinking water storage tanks (MDWSTs), given the absence of such data across the United States.Sediment samples (87 MDWST) from eighteen locations across ten states of the United States were collected and assayed by qPCR for a range of potential enteric and opportunistic microbial pathogens and a sewage-associated Bacteroides marker. Potential opportunistic pathogens dominated, with the highest detection of occurrence (per cent positive detection; average cell equivalence (CE)) being Mycobacterium spp. (889%; 67 85 10(4) CE g(-1) ), followed by Legionella spp. (667%; 52 59 10(3) CE g(-1) ), Pseudomonas aeruginosa (222%; 250 880 CE g(-1) ) and Acanthamoeba spp. (389%; 53 70 CE g(-1) ), with no detected Naegleria fowleri. Most enteric pathogens (Campylobacter jejuni, Escherichia coli 0157:H7, Salmonella enterica, Cryptosporidium parvum and Giardia duodenalis) were not detected, except for a trace signal for Campylobacter spp. There was significant correlation between the qPCR signals of Legionella spp. and Acanthamoeba spp. (R(2) = 061, n = 87, P = 00001). Diverse Legionella spp. including Leg. pneumophila, Leg. pneumophila sg1 and Leg. anisa were identified, each of which might cause legionellosis.These results imply that potential opportunistic pathogens are common within MDWST sediments and could act as a source of microbial contamination, but need downstream growth to be of potential concern.The results imply that opportunistic pathogen risks may need to be managed by regular tank cleaning or other management practices.


Kendall M.S.,National Oceanic and Atmospheric Administration | Poti M.,National Oceanic and Atmospheric Administration | Poti M.,Dynamac Inc. | Karnauskas K.B.,University of Colorado at Boulder
Global Change Biology | Year: 2016

Changes in larval import, export, and self-seeding will affect the resilience of coral reef ecosystems. Climate change will alter the ocean currents that transport larvae and also increase sea surface temperatures (SST), hastening development, and shortening larval durations. Here, we use transport simulations to estimate future larval connectivity due to: (1) physical transport of larvae from altered circulation alone, and (2) the combined effects of altered currents plus physiological response to warming. Virtual larvae from islands throughout Micronesia were moved according to present-day and future ocean circulation models. The Hybrid Coordinate Ocean Model (HYCOM) spanning 2004-2012 represented present-day currents. For future currents, we altered HYCOM using analysis from the National Center for Atmospheric Research Community Earth System Model, version 1-Biogeochemistry, Representative Concentration Pathway 8.5 experiment. Based on the NCAR model, regional SST is estimated to rise 2.74 °C which corresponds to a ~17% decline in larval duration for some taxa. This reduction was the basis for a separate set of simulations. Results predict an increase in self-seeding in 100 years such that 62-76% of islands experienced increased self-seeding, there was an average domainwide increase of ~1-3% points in self-seeding, and increases of up to 25% points for several individual islands. When changed currents alone were considered, approximately half (i.e., random) of all island pairs experienced decreased connectivity but when reduced PLD was added as an effect, ~65% of connections were weakened. Orientation of archipelagos relative to currents determined the directional bias in connectivity changes. There was no universal relationship between climate change and connectivity applicable to all taxa and settings. Islands that presently export large numbers of larvae but that also maintain or enhance this role into the future should be the focus of conservation measures that promote long-term resilience of larval supply. © 2016 John Wiley & Sons Ltd.


Lu J.,U.S. Environmental Protection Agency | Gerke T.L.,U.S. Environmental Protection Agency | Gerke T.L.,University of Cincinnati | Buse H.Y.,U.S. Environmental Protection Agency | And 3 more authors.
Journal of Water and Health | Year: 2014

A quantitative polymerase chain reaction assay (115 bp amplicon) specific to Escherichia coli K12 with an ABI™ internal control was developed based on sequence data encoding the rfb gene cluster. Assay specificity was evaluated using three E. coli K12 strains (ATCC W3110, MG1655 & DH1), 24 non-K12 E. coli and 23 bacterial genera. The biofilm detection limit was 103 colony-forming units (CFU) E. coli K12 mL-1, but required a modified protocol, which included a bio-blocker Pseudomonas aeruginosa with ethylenediaminetetraacetic acid buffered to pH 5 prior to cell lysis/DNA extraction. The novel protocol yielded the same sensitivity for drinking water biofilms associated with Fe3O4 (magnetite)-coated SiO2 (quartz) grains and biofilm-surface iron corrosion products from a drinking water distribution system. The novel DNA extraction protocol and specific E. coli K12 assay are sensitive and robust enough for detection and quantification within iron drinking water pipe biofilms, and are particularly well suited for studying enteric bacterial interactions within biofilms. © IWA Publishing 2014.


Dave A.,NASA | Dave A.,Lockheed Martin | Thompson S.J.,NASA | Thompson S.J.,CA Technologies | And 11 more authors.
Astrobiology | Year: 2013

The Mars Icebreaker Life mission will search for subsurface life on Mars. It consists of three payload elements: a drill to retrieve soil samples from approximately 1 m below the surface, a robotic sample handling system to deliver the sample from the drill to the instruments, and the instruments themselves. This paper will discuss the robotic sample handling system. Collecting samples from ice-rich soils on Mars in search of life presents two challenges: protection of that icy soil - considered a "special region" with respect to planetary protection - from contamination from Earth, and delivery of the icy, sticky soil to spacecraft instruments. We present a sampling device that meets these challenges. We built a prototype system and tested it at martian pressure, drilling into ice-cemented soil, collecting cuttings, and transferring them to the inlet port of the SOLID2 life-detection instrument. The tests successfully demonstrated that the Icebreaker drill, sample handling system, and life-detection instrument can collectively operate in these conditions and produce science data that can be delivered via telemetry - from dirt to data. Our results also demonstrate the feasibility of using an air gap to prevent forward contamination. We define a set of six analog soils for testing over a range of soil cohesion, from loose sand to basalt soil, with angles of repose of 27 and 39 , respectively. Particle size is a key determinant of jamming of mechanical parts by soil particles. Jamming occurs when the clearance between moving parts is equal in size to the most common particle size or equal to three of these particles together. Three particles acting together tend to form bridges and lead to clogging. Our experiments show that rotary-hammer action of the Icebreaker drill influences the particle size, typically reducing particle size by ∼100 μm. © Mary Ann Liebert, Inc.


Lu J.,U.S. Environmental Protection Agency | Buse H.Y.,Dynamac Inc. | Gomez-Alvarez V.,U.S. Environmental Protection Agency | Struewing I.,Dynamac Inc. | And 2 more authors.
Journal of Applied Microbiology | Year: 2014

Aims: This study examined the impact of pipe materials and introduced Legionella pneumophila on downstream Leg. pneumophila colonization and microbial community structures under conditions of low flow and low chlorine residual. Methods and Results: CDC biofilm™ reactors containing either unplasticized polyvinylchloride (uPVC) or copper (Cu) coupons were used to develop mature biofilms on Norprene™ tubing effluent lines to simulate possible in-premise biofilm conditions. The microbial communities were characterized through 16S and 18S rRNA gene clone libraries and Leg. pneumophila colonization was determined via specific qPCR assays. The Cu significantly decreased downstream microbial diversity, approximately halved bacterial and eukaryotic abundance, with some groups only detected in uPVC-reactor tubing biofilms. However, some probable amoeba-resisting bacteria (ARB) like Mycobacterium spp. and Rhodobacteraceae were significantly more abundant in the Cu than uPVC-reactor tubing biofilms. In particular, Leg. pneumophila only persisted (postinoculation) within the Cu-reactor tubing biofilms, and the controlled low chlorine residue and water flow conditions led to a general high abundance of possible free-living protozoa in all tubing biofilms. The higher relative abundance of ARB-like sequences from Cu-coupons vs uPVC may have been promoted by amoebal selection and subsequent ARB protection from Cu inhibitory effects. Conclusions: Copper pipe and low flow conditions had significant impact on downstream biofilm microbial structures (on plastic pipe) and the ability for Leg. pneumophila colonization post an introduction event. Significance and Impact of the Study: This is the first report that compares the effects of copper and uPVC materials on downstream biofilm communities grown on a third (Norprene™) surface material. The downstream biofilms contained a high abundance of free-living amoebae and ARB, which may have been driven by a lack of residual disinfectant and periodic stagnant conditions. Given the prevalence of Cu-piping in buildings, there may be increased risk from drinking water exposures to ARB following growth on pipe/fixture biofilms within premise drinking water systems. © 2014.


Fisher J.W.,NASA | Hogan J.A.,NASA | Pace G.S.,Lockheed Martin | Pace G.S.,NASA | And 2 more authors.
40th International Conference on Environmental Systems, ICES 2010 | Year: 2010

Future extended lunar surface missions will require extensive recovery of resources to reduce mission costs and enable self-sufficiency. Water is of particular importance due to its potential use for human consumption and hygiene, general cleaning, clothes washing, radiation shielding, cooling for extravehicular activity suits, and oxygen and hydrogen production. Various water sources are inherently present or are generated in lunar surface missions, and subject to recovery. They include: initial water stores, water contained in food, human and other solid wastes, wastewaters and associated brines, ISRU water, and scavenging from residual propellant in landers. This paper presents the results of an analysis of the contribution of water recovery from life support wastes on the overall water balance for lunar surface missions. Water in human wastes, metabolic activity and survival needs are well characterized and dependable data are available. A detailed life support waste model was developed that summarizes the composition of life support wastes and their water content. Waste processing technologies were reviewed for their potential to recover that water. The recoverable water in waste is a significant contribution to the overall water balance. The value of this contribution is discussed in the context of the other major sources and losses of water. Combined with other analyses these results provide guidance for research and technology development and down-selection.

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