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Broader Impacts and Outreach Videos on Ocean Physics and Biogeochemistry
This is just a preliminary NF1676 in advance of filming for a project....A convergent team of experts in biology, chemistry, physics, engineering, mathematics, and computational modeling examine how dynamic and coupled phytoplankton-pathogen-particle-predator linkages coalesce to explain the observed high spatial variability in the efficiency of the export of particulate organic carbon (POC) to the deep ocean. They elucidate and quantify the linkages between viruses and ballast minerals to increase understanding of carbon cycling in the oceanic biological carbon pump and the impact of viruses within it. By providing knowledge than can be used to improve the parameterization of carbon export in Earth system models, the project will help reduce uncertainty in regional marine biogeochemical projections, potentially improving marine ecosystem and fisheries management on timescales from seasons to decades. The project includes activities that provide teaching resources and hands-on training to educators within a ‘Tools of Science’ program that provides a simple and succinct way to communicate the process of scientific research to students in a way that is useful to teachers. The project couples laboratory-based experiments on model host-virus-grazer systems with extensive field based observational and manipulative studies on natural populations of diatoms and coccolithophores, the two phytoplankton groups that account for most of the estimated particulate organic matter flux to the deep ocean. Experiments and measurements integrate diagnostic biological and chemical controls on infection and particle coagulation theory with microscale physics and grazing to quantify links to each hypothesized export mechanism under field-relevant turbulent conditions. Cutting-edge engineering and analytical tools are used to diagnose and track infection dynamics while characterizing and quantifying particle aggregation and disaggregation, mineral dissolution, sinking dynamics, grazing rates, and fecal pellet production at unprecedented resolution and under well-defined, microscale physical regimes. Field campaigns elucidate the relative efficiency of hypothesized mechanisms in stimulating POC export in natural blooms, while providing bulk and size-resolved estimates of POC flux.
Increased susceptibility to Pseudomonas aeruginosa infection under hindlimb-unloading conditions
It has been reported that spaceflight conditions alter the immune system and resistance to infection [Belay T, Aviles H, Vance M, Fountain K, and Sonnenfeld G. J Allergy Clin Immunol 170: 262-268, 2002; Hankins WR and Ziegelschmid JF. In: Biomedical Results of Apollo. Washington, DC: NASA, 1975, p. 43-81. (NASA Spec. Rep. SP-368)]. Ground-based models, including the hindlimb-unloading model, have become important tools for increasing understanding of how spaceflight conditions can influence physiology. The objective of the present study was to determine the effect of hindlimb unloading on the susceptibility of mice to Pseudomonas aeruginosa infection. Hindlimb-unloaded and control mice were subcutaneously infected with 1 LD50 of P. aeruginosa. Survival, bacterial organ load, and antibody and corticosterone levels were compared among the groups. Hindlimb unloading had detrimental effects for infected mice. Animals in the hindlimb-unloaded group, compared with controls, 1). showed significantly increased mortality and reduced time to death, 2). had increased levels of corticosterone, and 3). were much less able to clear bacteria from the organs. These results suggest that hindlimb unloading may induce the production of corticosterone, which may play a critical role in the modulation of the immune system leading to increased susceptibility to P. aeruginosa infection.
Use of Remote Sensing/Geographical Information Systems (RS/GIS) to Identify the Distributional Limits of Soil-Transmitted Helminths (STHs) and Their Association to Prevalence of Intestinal Infection in School-Age Children in Four Rural Communities in Boaco, Nicaragua
STHs can infect all members of a population but school-age children living in poverty are at greater risk. Infection can be controlled with drug treatment, health education and sanitation. Helminth control programs often lack resources and reliable information to identify areas of highest risk to guide interventions and to monitor progress. Objectives: To use RS/GIS to identify the environmental variables that correlate with the ecology of STHs and with the prevalence of STH infections. Methods: Geo-referenced in situ prevalence data will be overlaid over an ecological map derived from the RS environmental data using ESRI s ArcGIS 9.3. Prevalence data and RS environmental data matching at the same geographical location will be analyzed for correlation and those RS environmental variables that better correlate with prevalence data will be included in a multivariate regression model. Temperature, vegetation, and distance to bodies of water will be inferred using data from the Moderate-Resolution Imaging Spectroradiometer (MODIS) onboard the Terra and Aqua satellites, and Thematic Mapper (TM) and Enhance Thematic Mapper Plus (ETM+) satellite sensors onboard Landsat 5 and Landsat 7 respectively. Elevation will be estimated with data from The Shuttle Radar Topography Mission (SRTM). Prevalence and intensity of infections will be determined by parasitological survey (Kato Katz) of children enrolled in rural schools in Boaco, Nicaragua, in the communities of El Roblar, Cumaica Norte, Malacatoya 1, and Malacatoya 2). Expected Results: Associations between RS environmental data and prevalence in situ data will be determined and their applications to public health will be discussed. Discussion/Conclusions: The use of RS/GIS data to predict the prevalence of STH infections could be useful for helminth control programs, providing improved geographical guidance of interventions while increasing cost-effectiveness. Learning Objectives: (1) To identify the RS environmental variables that can help predict the prevalence of STH infections. (2) To understand potential applications of RS/GIS to national helminth control programs. (3) To asses the applicability of RS/GIS to control STH infections.
Cortical neuronal cytoskeletal changes associated with FIV infection
HIV-1 infection is often complicated by central nervous system (CNS) dysfunction. Degenerative neuronal changes as well as neuronal loss have been documented in individuals with AIDS. Feline immunodeficiency virus (FIV) infection of cats provides a model for both the immune and the central nervous system manifestations of HIV infection of humans. In this study we have examined neurons in the frontal cortex of feline immunodeficiency virus-infected cats and controls for immunoreactivity with SMI 32, an antibody recognizing a non-phosphorylated epitope on neurofilaments. We noted a significant increase in the number of immunoreactive pyramidal cells in infected animals compared to controls. The changes seen in the neuronal cytoskeleton as a consequence of the inoculation with FIV were similar to those seen in humans undergoing the normal aging process as well as those suffering from neurological diseases, including Alzheimer's and dementia pugilistica. The changes we noted in the feline brain were also similar to that reported in animals with traumatic injuries or with spontaneously occurring or induced motor neuron diseases, suggesting that the increase in reactivity represents a deleterious effect of FIV on the central nervous system.
Effects of the hindlimb-unloading model of spaceflight conditions on resistance of mice to infection with Klebsiella pneumoniae
BACKGROUND: It has been well documented in several studies that many immunologic parameters are altered in experimental animals and human subjects who have flown in space. However, it is not fully known whether these immunologic changes could result in increased susceptibility to infection. Hindlimb (antiorthostatic) unloading of rodents has been used successfully to simulate some of the effects of spaceflight on physiologic systems. OBJECTIVE: The objective of this study was to determine the effect of hindlimb unloading on the outcome of Klebsiella pneumoniae infection in mice. METHODS: Hindlimb-unloaded, hindlimb-restrained, and control mice were intraperitoneally infected with one 50% lethal dose of K pneumoniae 2 days after suspension. Mortality and bacterial load in several organs were compared among the groups. RESULTS: Unloaded mice showed significantly increased mortality and reduced mean time to death compared with that seen in the control groups. Kinetics of bacterial growth with smaller infective doses revealed that control mice were able to clear bacteria from the organs after 30 hours. In contrast, unloaded mice had continued bacterial growth at the same time point. CONCLUSION: The results of this study suggest that hindlimb unloading might enhance the dissemination of K pneumoniae, leading to increased mortality. The complex physiologic changes observed during hindlimb unloading, including stress, have a key role in the pathophysiology of this infection.
Cytokines and immune surveillance in humans
Evidence from both human and rodent studies has indicated that alterations in immunological parameters occur after space flight. Among the parameters shown, by us and others, to be affected is the production of interferons. Interferons are a family of cytokines that are antiviral and play a major role in regulating immune responses that control resistance to infection. Alterations in interferon and other cytokine production and activity could result in changes in immunity and a possible compromise of host defenses against both opportunistic and external infections. The purpose of the present study is to further explore the effects of space flight on cytokines and cytokine-directed immunological function.
Cytokines and immune surveillance in humans
Evidence from both human and rodent studies has indicated that alterations in immunological parameters occur after space flight. Among the parameters shown, by us and others, to be affected is the production of interferons. Interferons are a family of cytokines that are antiviral and play a major role in regulating immune responses that control resistance to infection. Alterations in interferon and other cytokine production and activity could result in changes in immunity and a possible compromise of host defenses against both opportunistic and external infections. The purpose of the present study is to explore further the effects of space flight on cyotokines and cytokine-directed immunological function. Among the tests carried out are interferon-alpha production, interferon-gamma production, interleukin-1 and -2 production, signal transduction in neutrophils, signal transduction in monocytes, and monocyte phagocytic activity. The experiments will be performed using peripheral blood obtained from human subjects. It is our intent to eventually carry out these experiments using astronauts as subjects to determine the effects of space flight on cytokine production and activity. However, these subjects are not currently available. Until they become available, we will carry out these experiments using subjects maintained in the bed-rest model for microgravity.
Hawai'i Water Resources: Utilizing NASA Earth Observations to Assess Ocean Conditions Leading to the Spread of the Nuisance Red Algae (Chondria tumulosa) in Papahānaumokuākea Marine National Monument, Hawai’i
Chondria tumulosa, a newly discovered red alga, was observed in low abundance in 2016 but has since proliferated and is now smothering and decimating vast expanse of coral reefs in Manawai, located in Papahānaumokuākea Marine National Monument (PMNM). If the spread persists, the outbreak of this cryptogenic species could potentially cause region-wide ecosystem degradation. In coordination with the U.S. Fish and Wildlife Service, Marine National Monuments of the Pacific and the National Oceanographic and Atmospheric Administration (NOAA) Office of National Marine Sanctuaries’ Papahānaumokuākea Marine National Monument, this project created a tool to analyze oceanographic conditions (sea surface temperature (SST), chlorophyll-a, water velocity, salinity, turbidity) across the Monument that could potentially be driving the algal spread. The Google Earth Engine tool enabled the partners to visualize oceanographic conditions and gather time-series graphs utilizing Aqua and Terra Moderate Resolution Imaging Spectroradiometer (MODIS), Suomi National Polar-orbiting Partnership (NPP) Visible Infrared Imaging Radiometer Suite (VIIRS), Sentinel-3 Ocean and Land Colour Instrument (OLCI), Hybrid Coordinate Ocean Model (HYCOM) and NOAA's Climate Data Record in a user-friendly interface. The team used in situ SST data from subsurface temperature recorders provided by the partners to validate the tool's accuracy. Preliminary statistical analysis of MODIS data found warming trends in SST in Manawai as well as increased chlorophyll-a levels during the summer months in contrast to the control (non-infected) Lalo atoll. The tool did not aim to classify algal presence due to limited availability of higher resolution satellite imagery but instead enabled PMNM managers to monitor conditions that may be conducive to algal growth around the monument to make informed decisions and mitigation practices.
The Effects of Simulated Weightlessness on Susceptibility to Viral and Bacterial Infections Using a Murine Model
Certain immunological responses may be compromised as a result of changes in environmental conditions, such as the physiological adaptation to and from the weightlessness which occurs during space flight and recovery. A murine antiorthostatic model was developed to simulate weightlessness. Using this model, the proposed study will determine if differences in susceptibility to viral and bacterial infections exist among mice suspended in an antiorthostatic orientation to simulate weightlessness, mice suspended in an orthostatic orientation to provide a stressful situation without the condition of weightlessness simulation, and non-suspended control mice. Inbred mouse strains which are resistant to the diabetogenic effects of the D variant of encephalomyocarditis virus (EMC-D) and the lethal effects of Salmonella typhimurium will be evaluated. Glucose tolerance tests will be performed on all EMC-D-infected and non-infected control groups. The incidence of EMC-D-induced diabetes and the percentage survival of S. typhimurium-infected animals will be determined in each group. An additional study will determine the effects of simulated weightlessness on murine responses to exogenous interferon.
The role of plant disease in the development of controlled ecological life support systems
Plant diseases could be important factors affecting growth of higher plants in Closed Ecological Life Support Systems (CELSS). Disease control, therefore, will be needed to maintain healthy plants. The most important controls should be aimed at preventing the introduction, reproduction and spread of pathogens and preventing plant infection. An integrared ease control program will maximize that approach. In the design and operation of CELSS, plant disease should be considered an important aspect of plant growth. The effects of plant diseases are reviewed and several disease control measures are discussed.
Desorption Electrospray Ionization–Mass Spectrometry Imaging Provides Spatiochemical Information on Potential Biocontrol Agents against Phytophthora capsici Infection in Tomato Plants
Biological control agents can offer an eco-friendly and more sustainable alternative to conventional chemical pesticides, providing protection against destructive pathogens, such as Phytophthora capsici, while reducing potential environmental harm associated with synthetic pesticide use in agricultural systems. This work evaluates the biocontrol effectiveness of Bacillus vallismortis, Bacillus amyloliquefaciens, Bacillus thuringiensis, and Bacillus subtilis, against the widespread plant pathogen Phytophthora capsici. Our studies showed that Bacillus thuringiensis and Bacillus subtilis promote plant growth and provide protection against Phytophthora capsici in both in vitro and in vivo greenhouse studies, while Bacillus vallismortis and Bacillus amyloliquefaciens were effective in vitro but not in vivo. Specifically, Bacillus thuringiensis was observed to both hinder the growth of Phytophthora capsici and enhance plant resilience to this pathogen, with B. thuringiensis-treated, pathogen-exposed plants displaying a 94.4% increase in root length and a 74.0% increase in shoot height compared to plants with only oomycete exposure. To probe the molecular interactions between the biocontrol agent and pathogen, a dual culture of Bacillus thuringiensis and Phytophthora capsici was analyzed in situ using a desorption electrospray ionization–mass spectrometry imaging (DESI-MSI) workflow. This approach interrogated the spatially oriented biochemical interactions that may serve as the molecular foundation for the effectiveness of these biological control agents in crop protection, identifying seven unique phenotypic regions within the dual culture. Herein, we demonstrate the benefits of biological control agent application in tomato cultivation and showcase the strengths of desorption electrospray ionization–mass spectrometry imaging when applied to the spatially resolved molecular characterization of agriculturally relevant microorganisms.
Patulin Inhibition of Specific Apple Microbiome Members Uncovers Hanseniaspora uvarum as a Potential Biocontrol Agent
Penicillium expansum is a major postharvest pathogen of apples, causing loss in fruits through tissue damage, as well as in apple products due to contamination with the mycotoxin patulin. During infections, patulin is a cultivar-dependent virulence factor that facilitates apple lesion development. Patulin also has characterized antimicrobial activity and is important for inhibiting other competitive phytopathogens, but the role of this inhibitory activity has not been investigated in the context of the apple microbiome. Here, in our current study, we isolated 68 apple microbiota and characterized their susceptibility to P. expansum extracts. We found gram-negative bacteria and basidiomycete yeast to demonstrate largely patulin-specific growth inhibition compared with gram-positive and ascomycete isolates. From co-cultures, we identified a Hanseniaspora and Gluconobacter pairing that reduced P. expansum biomass and found that H. uvarum alone is sufficient to reduce apple disease progression in vivo. We investigated possible mechanisms of H. uvarum biocontrol activity and found modest inhibition on apple puree plates, as well as a trend toward lower patulin levels at the wound site. Active biocontrol activity required live yeast, which was also effective in controlling Botrytis cinerea apple infections. Lastly, we explored the breadth of H. uvarum biocontrol activity with over 30 H. uvarum isolates and found consistent inhibition of P. expansum apple disease.
Lipophilic bisphosphonates reduced cyst burden and ameliorated hyperactivity of mice chronically infected with Toxoplasma gondii
ABSTRACT The current treatments for toxoplasmosis are only active against fast-growing tachyzoites, present in acute infections, with little effect on slow-growing bradyzoites within tissue cysts, present in latent chronic infections. The mitochondrion ofToxoplasma gondiiis essential for its survival, and one of the major anti-parasitic drugs, atovaquone, inhibits the mitochondrial electron transport chain at the coenzyme Q:cytochrome c oxidoreductase site. Coenzyme Q (also known as ubiquinone [UQ]) consists of a quinone head and a lipophilic, isoprenoid tail that anchors UQ to membranes. The synthesis of the isoprenoid unit is essential for cell growth and is inhibited by lipophilic bisphosphonates, which inhibit the parasite growth. In this work, we investigated the effect of lipophilic bisphosphonates on the chronic stages ofT. gondii. We discovered that three lipophilic bisphosphonates (BPH-1218, BPH-1236, and BPH-1238), effective for the acute infection, were also effective in controlling the development of chronic stages. We showed effectiveness by testing them againstin vitrocysts andin vivoderived tissue cysts and, most importantly, these compounds reduced the cyst burden in the brains of chronically infected mice. We monitored the activity of infected mice non-invasively and continuously with a novel device termed the CageDot. A decrease in activity accompanied the acute phase, but mice recovered to normal activity and showed signs of hyperactivity when the chronic infection was established. Moreover, treatment with atovaquone or BPH-1218 ameliorated the hyperactivity observed during the chronic infection. IMPORTANCE Treatment for toxoplasmosis is challenged by a lack of effective drugs to eradicate the chronic stages. Most of the drugs currently used are poorly distributed to the central nervous system, and they trigger allergic reactions in a large number of patients. There is a compelling need for safe and effective treatments for toxoplasmosis. Bisphosphonates (BPs) are analogs of inorganic pyrophosphate and are used for the treatment of bone disorders. BPs target the isoprenoid pathway and are effective against several experimental parasitic infections. Some lipophilic BPs can specifically inhibit the mitochondrial activity ofToxoplasma gondiiby interfering with the mechanism by which ubiquinone is inserted into the inner mitochondrial membrane. In this work, we present the effect of three lipophilic BPs againstT. gondiichronic stages. We also present a new strategy for the monitoring of animal activity during disease and treatment that is non-invasive and continuous.
Parabarosis and experimental infections. II - Body temperatures of small animals; methods of observation and control
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Pseudomonas aeruginosa Adhesion and Biofilm Formation on Poly(l-lysine)-Tethered Hydrogels: Synergistic Effect of Substrate Stiffness and Positive Charge Density
Infections associated with antibacterial-resistant Pseudomonas aeruginosa (P. aeruginosa) are the major cause of morbidity and mortality of patients, presenting one of the greatest therapeutic challenges for treatment of community-acquired and nosocomial infections. To develop antimicrobial hydrogel coatings to control the adhesion and subsequent biofilm formation of P. aeruginosa, we have used photo-cross-linked poly(ethylene glycol) diacrylate (PEGDA) hydrogels with varied cross-linking densities and covalently grafted poly(l-lysine) (PLL) at different weight compositions (ϕ PLL ). Both surface stiffness and positive charge density of the hydrogels were efficiently tuned over a broad range to investigate their effects on two main strains of P. aeruginosa, PA01 and PA14. We found that both number and viability of attached cells were positively correlated with the hydrogel stiffness, leading to thicker and larger coverage of cell colonies at 72 h postseeding on the stiffer substrates. The dependence of both PA01 and PA14 strains on ϕ PLL , however, was nonmonotonic. Positive charges from dissociated amine groups in the grafted PLL chains significantly promoted initial adhesion and proliferation of both strains at low ϕ PLL and developed into the thickest biofilms on the stiffest hydrogels grafted with ϕ PLL of 1–2%. Nevertheless, on the softest hydrogels grafted with PLL at high ϕ PLL of 7–10%, the bacteria no longer attached or survived. These results not only improved our fundamental understanding of bacteria-material interactions but also provided a series of PLL-grafted PEGDA hydrogels with controlled stiffness and positive charge density as ideal surface coating materials to prevent bacterial infections.
Effects of space flight conditions on the function of the immune system and catecholamine production simulated in a rodent model of hindlimb unloading
The rodent model of hindlimb unloading has been successfully used to simulate some of the effects of space flight conditions. Previous studies have indicated that mice exposed to hindlimb-unloading conditions have decreased resistance to infections compared to restrained and normally housed control mice. OBJECTIVE: The purpose of this study was to clarify the mechanisms involved in resistance to infection in this model by examining the effects of hindlimb unloading on the function of the immune system and its impact on the production of catecholamines. METHODS: Female Swiss Webster mice were hindlimb-unloaded during 48 h and the function of the immune system was assessed in spleen and peritoneal cells immediately after this period. In addition, the kinetics of catecholamine production was measured throughout the hindlimb-unloading period. RESULTS: The function of the immune system was significantly suppressed in the hindlimb-unloaded group compared to restrained and normally housed control mice. Levels of catecholamines were increased in the hindlimb-unloaded group and peaked at 12 h following the commencement of unloading. CONCLUSION: These results suggest that physiological responses of mice are altered early after hindlimb unloading and that catecholamines may play a critical role in the modulation of the immune system. These changes may affect the ability of mice to resist infections. Copyright (c) 2005 S. Karger AG, Basel.
Lyophilization of ASFV vaccine candidate ASFV-G-ΔI177L offers long term stability
Abstract For over a century African swine fever (ASF) has been causing outbreaks leading to devastating losses for the swine industry. The current pandemic of ASF has shown no signs of stopping and continues to spread causing outbreaks in additional countries. Currently control relies mostly on culling infected farms, and strict biosecurity procedures. Recently a vaccine, ASFV-G-ΔI177L was approved for use in Vietnam. In this study we evaluate the long-term stability of lyophilized ASFV-G-ΔI177L. Understanding the stability of different formulations of vaccines is information necessary for deployment of vaccines to ASF outbreak areas, particularly those that do not have a reliable well established cold chain to ensure conservation of vaccine quality. In this report, we determined that ASFV-G-ΔI177L, when lyophilized under specific conditions, is stable for up to one year at 4 °C, with similar vaccine titers after storage. Next-generation sequencing analysis also determined that lyophilization and long-term storage under these conditions had no effect on the genome of ASFV as the genome remained genetically identical to the original non-lyophilized form.