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Sample records for algal cells exposed

  1. Centriole asymmetry determines algal cell geometry

    PubMed Central

    Marshall, Wallace F.

    2012-01-01

    The mechanisms that determine the shape and organization of cells remain largely unknown. Green algae such as Chlamydomonas provide excellent model systems for studying cell geometry due to their highly reproducible cell organization. Structural and genetic studies suggest that asymmetry of the centriole (basal body) plays a critical determining role in organizing the internal organization of algal cells, through the attachment of microtubule rootlets and other large fiber systems to specific sets of microtubule triplets on the centriole. Thus to understand cell organization, it will be critical to understand how the different triplets of the centriole come to have distinct molecular identities. PMID:23026116

  2. Air pollutant production by algal cell cultures

    NASA Technical Reports Server (NTRS)

    Fong, F.; Funkhouser, E. A.

    1982-01-01

    The production of phytotoxic air pollutants by cultures of Chlorella vulgaris and Euglena gracilis is considered. Algal and plant culture systems, a fumigation system, and ethylene, ethane, cyanide, and nitrogen oxides assays are discussed. Bean, tobacco, mustard green, cantaloupe and wheat plants all showed injury when fumigated with algal gases for 4 hours. Only coleus plants showed any resistance to the gases. It is found that a closed or recycled air effluent system does not produce plant injury from algal air pollutants.

  3. Algal Cell Factories: Approaches, Applications, and Potentials

    PubMed Central

    Fu, Weiqi; Chaiboonchoe, Amphun; Khraiwesh, Basel; Nelson, David R.; Al-Khairy, Dina; Mystikou, Alexandra; Alzahmi, Amnah; Salehi-Ashtiani, Kourosh

    2016-01-01

    With the advent of modern biotechnology, microorganisms from diverse lineages have been used to produce bio-based feedstocks and bioactive compounds. Many of these compounds are currently commodities of interest, in a variety of markets and their utility warrants investigation into improving their production through strain development. In this review, we address the issue of strain improvement in a group of organisms with strong potential to be productive “cell factories”: the photosynthetic microalgae. Microalgae are a diverse group of phytoplankton, involving polyphyletic lineage such as green algae and diatoms that are commonly used in the industry. The photosynthetic microalgae have been under intense investigation recently for their ability to produce commercial compounds using only light, CO2, and basic nutrients. However, their strain improvement is still a relatively recent area of work that is under development. Importantly, it is only through appropriate engineering methods that we may see the full biotechnological potential of microalgae come to fruition. Thus, in this review, we address past and present endeavors towards the aim of creating productive algal cell factories and describe possible advantageous future directions for the field. PMID:27983586

  4. Algal Cell Factories: Approaches, Applications, and Potentials.

    PubMed

    Fu, Weiqi; Chaiboonchoe, Amphun; Khraiwesh, Basel; Nelson, David R; Al-Khairy, Dina; Mystikou, Alexandra; Alzahmi, Amnah; Salehi-Ashtiani, Kourosh

    2016-12-13

    With the advent of modern biotechnology, microorganisms from diverse lineages have been used to produce bio-based feedstocks and bioactive compounds. Many of these compounds are currently commodities of interest, in a variety of markets and their utility warrants investigation into improving their production through strain development. In this review, we address the issue of strain improvement in a group of organisms with strong potential to be productive "cell factories": the photosynthetic microalgae. Microalgae are a diverse group of phytoplankton, involving polyphyletic lineage such as green algae and diatoms that are commonly used in the industry. The photosynthetic microalgae have been under intense investigation recently for their ability to produce commercial compounds using only light, CO₂, and basic nutrients. However, their strain improvement is still a relatively recent area of work that is under development. Importantly, it is only through appropriate engineering methods that we may see the full biotechnological potential of microalgae come to fruition. Thus, in this review, we address past and present endeavors towards the aim of creating productive algal cell factories and describe possible advantageous future directions for the field.

  5. Algal Cell Response to Pulsed Waved Stimulation and Its Application to Increase Algal Lipid Production

    PubMed Central

    Savchenko, Oleksandra; Xing, Jida; Yang, Xiaoyan; Gu, Quanrong; Shaheen, Mohamed; Huang, Min; Yu, Xiaojian; Burrell, Robert; Patra, Prabir; Chen, Jie

    2017-01-01

    Generating renewable energy while sequestering CO2 using algae has recently attracted significant research attention, mostly directing towards biological methods such as systems biology, genetic engineering and bio-refining for optimizing algae strains. Other approaches focus on chemical screening to adjust culture conditions or culture media. We report for the first time the physiological changes of algal cells in response to a novel form of mechanical stimulation, or a pulsed wave at the frequency of 1.5 MHz and the duty cycle of 20%. We studied how the pulsed wave can further increase algal lipid production on top of existing biological and chemical methods. Two commonly used algal strains, fresh-water Chlorella vulgaris and seawater Tetraselmis chuii, were selected. We have performed the tests in shake flasks and 1 L spinner-flask bioreactors. Conventional Gravimetric measurements show that up to 20% increase for algal lipid could be achieved after 8 days of stimulation. The total electricity cost needed for the stimulations in a one-liter bioreactor is only one-tenth of a US penny. Gas liquid chromatography shows that the fatty acid composition remains unchanged after pulsed-wave stimulation. Scanning electron microscope results also suggest that pulsed wave stimulation induces shear stress and thus increases algal lipid production. PMID:28186124

  6. Algal Cell Response to Pulsed Waved Stimulation and Its Application to Increase Algal Lipid Production

    NASA Astrophysics Data System (ADS)

    Savchenko, Oleksandra; Xing, Jida; Yang, Xiaoyan; Gu, Quanrong; Shaheen, Mohamed; Huang, Min; Yu, Xiaojian; Burrell, Robert; Patra, Prabir; Chen, Jie

    2017-02-01

    Generating renewable energy while sequestering CO2 using algae has recently attracted significant research attention, mostly directing towards biological methods such as systems biology, genetic engineering and bio-refining for optimizing algae strains. Other approaches focus on chemical screening to adjust culture conditions or culture media. We report for the first time the physiological changes of algal cells in response to a novel form of mechanical stimulation, or a pulsed wave at the frequency of 1.5 MHz and the duty cycle of 20%. We studied how the pulsed wave can further increase algal lipid production on top of existing biological and chemical methods. Two commonly used algal strains, fresh-water Chlorella vulgaris and seawater Tetraselmis chuii, were selected. We have performed the tests in shake flasks and 1 L spinner-flask bioreactors. Conventional Gravimetric measurements show that up to 20% increase for algal lipid could be achieved after 8 days of stimulation. The total electricity cost needed for the stimulations in a one-liter bioreactor is only one-tenth of a US penny. Gas liquid chromatography shows that the fatty acid composition remains unchanged after pulsed-wave stimulation. Scanning electron microscope results also suggest that pulsed wave stimulation induces shear stress and thus increases algal lipid production.

  7. Algal Cell Response to Pulsed Waved Stimulation and Its Application to Increase Algal Lipid Production.

    PubMed

    Savchenko, Oleksandra; Xing, Jida; Yang, Xiaoyan; Gu, Quanrong; Shaheen, Mohamed; Huang, Min; Yu, Xiaojian; Burrell, Robert; Patra, Prabir; Chen, Jie

    2017-02-10

    Generating renewable energy while sequestering CO2 using algae has recently attracted significant research attention, mostly directing towards biological methods such as systems biology, genetic engineering and bio-refining for optimizing algae strains. Other approaches focus on chemical screening to adjust culture conditions or culture media. We report for the first time the physiological changes of algal cells in response to a novel form of mechanical stimulation, or a pulsed wave at the frequency of 1.5 MHz and the duty cycle of 20%. We studied how the pulsed wave can further increase algal lipid production on top of existing biological and chemical methods. Two commonly used algal strains, fresh-water Chlorella vulgaris and seawater Tetraselmis chuii, were selected. We have performed the tests in shake flasks and 1 L spinner-flask bioreactors. Conventional Gravimetric measurements show that up to 20% increase for algal lipid could be achieved after 8 days of stimulation. The total electricity cost needed for the stimulations in a one-liter bioreactor is only one-tenth of a US penny. Gas liquid chromatography shows that the fatty acid composition remains unchanged after pulsed-wave stimulation. Scanning electron microscope results also suggest that pulsed wave stimulation induces shear stress and thus increases algal lipid production.

  8. Algal cell disruption using microbubbles to localize ultrasonic energy.

    PubMed

    Krehbiel, Joel D; Schideman, Lance C; King, Daniel A; Freund, Jonathan B

    2014-12-01

    Microbubbles were added to an algal solution with the goal of improving cell disruption efficiency and the net energy balance for algal biofuel production. Experimental results showed that disruption increases with increasing peak rarefaction ultrasound pressure over the range studied: 1.90 to 3.07 MPa. Additionally, ultrasound cell disruption increased by up to 58% by adding microbubbles, with peak disruption occurring in the range of 10(8)microbubbles/ml. The localization of energy in space and time provided by the bubbles improve efficiency: energy requirements for such a process were estimated to be one-fourth of the available heat of combustion of algal biomass and one-fifth of currently used cell disruption methods. This increase in energy efficiency could make microbubble enhanced ultrasound viable for bioenergy applications and is expected to integrate well with current cell harvesting methods based upon dissolved air flotation.

  9. Energy evaluation of algal cell disruption by high pressure homogenisation.

    PubMed

    Yap, Benjamin H J; Dumsday, Geoff J; Scales, Peter J; Martin, Gregory J O

    2015-05-01

    The energy consumption of high pressure homogenisation (HPH) was analysed to determine the feasibility of rupturing algal cells for biodiesel production. Experimentally, the processing capacity (i.e. flow rate), power draw and cell disruption efficiency of HPH were independent of feed concentration (for Nannochloropsis sp. up to 25%w/w solids). Depending on the homogenisation pressure (60-150 MPa), the solids concentration (0.25-25%w/w), and triacylglyceride (TAG) content of the harvested algal biomass (10-30%), the energy consumed by HPH represented between 6% and 110-times the energy density of the resulting biodiesel. Provided the right species (weak cell wall and high TAG content) is selected and the biomass is processed at a sufficiently high solids concentration, HPH can consume a small fraction of the energy content of the biodiesel produced. This study demonstrates the feasibility of process-scale algal cell disruption by HPH based on its energy requirement.

  10. Arsenic (V) induces a fluidization of algal cell and liposome membranes.

    PubMed

    Tuan, Le Quoc; Huong, Tran Thi Thanh; Hong, Pham Thi Anh; Kawakami, Tomonori; Shimanouchi, Toshinori; Umakoshi, Hiroshi; Kuboi, Ryoichi

    2008-09-01

    Arsenate is one of the most poisonous elements for living cells. When cells are exposed to arsenate, their life activities are immediately affected by various biochemical reactions, such as the binding of arsenic to membranes and the substitution of arsenic for phosphate or the choline head of phospholipids in the biological membranes. The effects of arsenate on the life activities of algae Chlorella vulgaris were investigated at various concentrations and exposure times. The results demonstrated that the living activities of algal cells (10(10)cells/L) were seriously affected by arsenate at a concentration of more than 7.5mg As/L within 24h. Algal cells and the artificial membranes (liposomes) were exposed to arsenate to evaluate its effects on the membrane fluidization. In the presence of arsenate, the membranes were fluidized due to the binding and substitution of arsenate groups for phosphates or the choline head on the their membrane surface. This fluidization of the biological membranes was considered to enhance the transport of toxicants across the membrane of algal cells.

  11. Yield of trihalomethanes and haloacetic acids upon chlorinating algal cells, and its prediction via algal cellular biochemical composition.

    PubMed

    Hong, Hua Chang; Mazumder, Asit; Wong, Ming Hung; Liang, Yan

    2008-12-01

    The major objective of the present study was to investigate the contribution of major biomolecules, including protein, carbohydrates and lipids, in predicting DBPs formation upon chlorination of algal cells. Three model compounds, including bovine serum albumin (BSA), starch and fish oil, as surrogates of algal-derived proteins, carbohydrates and lipids, and cells of three algae species, representing blue-green algae, green algae, and diatoms, were chlorinated in the laboratory. The results showed that BSA (27 microg mg(-1) C) and fish oil (50 microg mg(-1) C) produced more than nine times higher levels of chloroform than starch (3 microg mg(-1) C). For the formation of HAAs, BSA was shown to have higher reactivity (49 microg mg(-1) C) than fish oil and starch (5 microg mg(-1) C). For the algal cells, Nitzschia sp. (diatom) showed higher chloroform yields (48 microg mg(-1) C) but lower HAA yields (43 microg mg(-1) C) than Chlamydomonas sp. (green algae) (chloroform: 34 microg mg(-1) C; HAA: 62 microg mg(-1) C) and Oscillatoria sp. (blue-green algae) (chloroform: 26 microg mg(-1) C; HAA: 72 microg mg(-1) C). The calculated chloroform formation of cells from the three algal groups, based on their biochemical compositions, was generally consistent with the experimental data, while the predicted values for HAAs were significantly lower than the observed ones. As compared to humic substances, such as humic and fulvic acids, the algal cells appeared to be important precursors of dichloroacetic acid.

  12. Separation of algal cells from water by column flotation

    SciTech Connect

    Liu, J.C.; Chen, Y.M.; Ju, Y.H.

    1999-08-01

    The dispersed air flotation (DiAF) process was utilized to separate algal cells (Chlorella sp.) from water. Two types of collector, cationic N-cetyl-N,N,N-trimethylammonium bromide (CTAB) and anionic sodium dodecylsulfate (SDS), were used. It was observed that 20% of cell removal was achieved in the presence of 40 mg/L of SDS, and ca. 86% of the cells were removed at 40 mg/L of CTAB. Upon the addition of 10 mg/L of chitosan, over 90% of the cells were removed when SDS (20 mg/L) was used as the collector. Air flow rate affected cell flotation slightly. Optimum pH values for cell flotation were from 4.0 to 5.0. Flotation efficiency decreased at high ionic strength. The electrostatic interaction between collector and cell surface plays a critical role in the separation processes.

  13. Immobilized algal cells used for hydrogen production

    SciTech Connect

    Hahn, John J.; Ghirardi, Maria L.; Jacoby, William A.

    2007-10-01

    This paper explores the use of the photosynthetic green alga Chlamydomonas reinhardtii bound to solid support particles to produce hydrogen in a two-step cycle. Bound cells are more easily cycled between growth mode and hydrogen production mode. The data indicate that the presence of silica particles does not inhibit the growth of the algae in the sulfur rich growth media. Filtration experiments reveal that the algae effectively bind to the silica particles, as high removal efficiencies are observed. The silica particles appear to approach saturation algae at a mass-loading ratio of about 0.035. In hydrogen production mode, the bound algae perform about as well as free-floating algae in terms of cumulative hydrogen production. A full-factorial experiment is described in which algae concentration was deemed to have a significant effect on cumulative hydrogen production.

  14. PCB UPTAKE AND ACCUMULATION BY OYSTERS (CRASSOSTREA VIRGINICA) EXPOSED VIA A CONTAMINATED ALGAL DIET. (R825349)

    EPA Science Inventory

    Abstract

    Reproductively active oysters were fed daily with 0.2 g algal paste containing 0, 0.1, and 1.0 small mu, Greekg polychlorinated biphenyls (PCBs) (1:1:1 mixture of Aroclor 1242, 1...

  15. Raman spectroscopy for the characterization of algal cells

    NASA Astrophysics Data System (ADS)

    Samek, Ota; Jonáš, Alexandr; Pilát, Zdeněk; Zemánek, Pavel; Nedbal, Ladislav; Tříska, Jan; Kotas, Petr; Trtílek, Martin

    2010-12-01

    Raman spectroscopy can elucidate fundamental questions about intercellular variability and what governs it. Moreover, knowing the metabolic response on single cell level this can significantly contribute to the study and use of microalgae in systems biology and biofuel technology. Raman spectroscopy is capable to measure nutrient dynamics and metabolism in vivo, in real-time, label free making it possible to monitor/evaluate population variability. Also, degree of unsaturation of the algae oil (iodine value) can be measured using Raman spectra obtained from single microalgae. The iodine value is the determination of the amount of unsaturation contained in fatty acids (in the form of double bonds). Here we demonstrate the capacity of the spatially resolved Raman microspectroscopy to determine the effective iodine value in lipid storage bodies of individual living algal cells. We employed the characteristic peaks in the Raman scattering spectra at 1,656 cm-1 (cis C=C stretching mode) and 1,445 cm-1 (CH2 scissoring mode) as the markers defining the ratio of unsaturated-to-saturated carbon-carbon bonds of the fatty acids in the algal lipids.

  16. The effect of light direction and suspended cell concentrations on algal biofilm growth rates.

    PubMed

    Schnurr, Peter J; Espie, George S; Allen, D Grant

    2014-10-01

    Algae biofilms were grown in a semicontinuous flat plate biofilm photobioreactor to study the effects of light direction and suspended algal cell populations on algal biofilm growth. It was determined that, under the growth conditions and biofilm thicknesses studied, light direction had no effect on long-term algal biofilm growth (26 days); however, light direction did affect the concentration of suspended algal cells by influencing the photon flux density in the growth medium in the photobioreactors. This suspended algal cell population affected short-term (7 days) algae cell recruitment and algal biofilm growth, but additional studies showed that enhanced suspended algal cell populations did not affect biofilm growth rates over the long term (26 days). Studying profiles of light transmittance through biofilms as they grew showed that most of the light became attenuated by the biomass after just a few days of growth (88 % after 3 days). The estimated biofilm thicknesses after these few days of growth were approximately 150 μm. The light attenuation data suggests that, although the biofilms grew to 700-900 μm, under these light intensities, only the first few hundred micrometers of the biofilm is receiving enough light to be photosynthetically active. We postulate that this photosynthetically active layer of the biofilm grows adjacent to the light source, while the rest of the biofilm is in a stationary growth phase. The results of this study have implications for algal biofilm photobioreactor design and operation.

  17. Coral host cells acidify symbiotic algal microenvironment to promote photosynthesis.

    PubMed

    Barott, Katie L; Venn, Alexander A; Perez, Sidney O; Tambutté, Sylvie; Tresguerres, Martin

    2015-01-13

    Symbiotic dinoflagellate algae residing inside coral tissues supply the host with the majority of their energy requirements through the translocation of photosynthetically fixed carbon. The algae, in turn, rely on the host for the supply of inorganic carbon. Carbon must be concentrated as CO2 in order for photosynthesis to proceed, and here we show that the coral host plays an active role in this process. The host-derived symbiosome membrane surrounding the algae abundantly expresses vacuolar H(+)-ATPase (VHA), which acidifies the symbiosome space down to pH ∼ 4. Inhibition of VHA results in a significant decrease in average H(+) activity in the symbiosome of up to 75% and a significant reduction in O2 production rate, a measure of photosynthetic activity. These results suggest that host VHA is part of a previously unidentified carbon concentrating mechanism for algal photosynthesis and provide mechanistic evidence that coral host cells can actively modulate the physiology of their symbionts.

  18. Coral host cells acidify symbiotic algal microenvironment to promote photosynthesis

    PubMed Central

    Barott, Katie L.; Venn, Alexander A.; Perez, Sidney O.; Tambutté, Sylvie; Tresguerres, Martin

    2015-01-01

    Symbiotic dinoflagellate algae residing inside coral tissues supply the host with the majority of their energy requirements through the translocation of photosynthetically fixed carbon. The algae, in turn, rely on the host for the supply of inorganic carbon. Carbon must be concentrated as CO2 in order for photosynthesis to proceed, and here we show that the coral host plays an active role in this process. The host-derived symbiosome membrane surrounding the algae abundantly expresses vacuolar H+-ATPase (VHA), which acidifies the symbiosome space down to pH ∼4. Inhibition of VHA results in a significant decrease in average H+ activity in the symbiosome of up to 75% and a significant reduction in O2 production rate, a measure of photosynthetic activity. These results suggest that host VHA is part of a previously unidentified carbon concentrating mechanism for algal photosynthesis and provide mechanistic evidence that coral host cells can actively modulate the physiology of their symbionts. PMID:25548188

  19. Production of biofuel using molluscan pseudofeces derived from algal cells

    DOEpatents

    Das, Keshav C.; Chinnasamy, Senthil; Shelton, James; Wilde, Susan B.; Haynie, Rebecca S.; Herrin, James A.

    2012-08-28

    Embodiments of the present disclosure provide for novel strategies to harvest algal lipids using mollusks which after feeding algae from the growth medium can convert algal lipids into their biomass or excrete lipids in their pseudofeces which makes algae harvesting energy efficient and cost effective. The bioconverter, filter-feeding mollusks and their pseudofeces can be harvested and converted to biocrude using an advanced thermochemical liquefaction technology. Methods, systems, and materials are disclosed for the harvest and isolation of algal lipids from the mollusks, molluscan feces and molluscan pseudofeces.

  20. Algal symbiont type affects gene expression in juveniles of the coral Acropora tenuis exposed to thermal stress.

    PubMed

    Yuyama, Ikuko; Harii, Saki; Hidaka, Michio

    2012-05-01

    Reef-building corals harbor symbiotic dinoflagellates, Symbiodinium spp., which are currently divided into several clades. The responses of corals associated with different Symbiodinium clades to thermal stress are not well understood, especially at a gene expression level. Juveniles of the coral Acropora tenuis inoculated with different algal types (clade A or D) were exposed to thermal stress and the expression levels of four putative stress-responsive genes, including genes coding green and red fluorescent proteins, an oxidative stress-responsive protein, and an ascorbic acid transporter, were analyzed by quantitative real-time PCR. The expression levels of the four genes decreased at high temperatures if juveniles were associated with clade A symbionts but increased if the symbionts were in clade D. The intensity of green fluorescence increased with temperature in clade D symbionts harboring juveniles, but not in juveniles associated with clade A symbionts. The present results suggest that genotypes of endosymbiotic algae affect the thermal stress responses of the coral juveniles.

  1. Raman microspectroscopy of individual algal cells: sensing unsaturation of storage lipids in vivo.

    PubMed

    Samek, Ota; Jonáš, Alexandr; Pilát, Zdeněk; Zemánek, Pavel; Nedbal, Ladislav; Tříska, Jan; Kotas, Petr; Trtílek, Martin

    2010-01-01

    Algae are becoming a strategic source of fuels, food, feedstocks, and biologically active compounds. This potential has stimulated the development of innovative analytical methods focused on these microorganisms. Algal lipids are among the most promising potential products for fuels as well as for nutrition. The crucial parameter characterizing the algal lipids is the degree of unsaturation of the constituent fatty acids quantified by the iodine value. Here we demonstrate the capacity of the spatially resolved Raman microspectroscopy to determine the effective iodine value in lipid storage bodies of individual living algal cells. The Raman spectra were collected from three selected algal species immobilized in an agarose gel. Prior to immobilization, the algae were cultivated in the stationary phase inducing an overproduction of lipids. We employed the characteristic peaks in the Raman scattering spectra at 1,656 cm(-1) (cis C═C stretching mode) and 1,445 cm(-1) (CH(2) scissoring mode) as the markers defining the ratio of unsaturated-to-saturated carbon-carbon bonds of the fatty acids in the algal lipids. These spectral features were first quantified for pure fatty acids of known iodine value. The resultant calibration curve was then used to calculate the effective iodine value of storage lipids in the living algal cells from their Raman spectra. We demonstrated that the iodine value differs significantly for the three studied algal species. Our spectroscopic estimations of the iodine value were validated using GC-MS measurements and an excellent agreement was found for the Trachydiscus minutus species. A good agreement was also found with the earlier published data on Botryococcus braunii. Thus, we propose that Raman microspectroscopy can become technique of choice in the rapidly expanding field of algal biotechnology.

  2. Bacterial tracking of motile algae assisted by algal cell's vorticity field.

    PubMed

    Locsei, J T; Pedley, T J

    2009-07-01

    Previously published experimental work by other authors has shown that certain motile marine bacteria are able to track free-swimming algae by executing a zigzag path and steering toward the algae at each turn. Here, we propose that the apparent steering behaviour could be a hydrodynamic effect, whereby an algal cell's vorticity and strain-rate fields rotate a pursuing bacterial cell in the appropriate direction. Using simplified models for the bacterial and algal cells, we numerically compute the trajectory of a bacterial cell and demonstrate the plausibility of this hypothesis.

  3. Thermal ecology on an exposed algal reef: infrared imagery a rapid tool to survey temperature at local spatial scales

    NASA Astrophysics Data System (ADS)

    Cox, T. E.; Smith, C. M.

    2011-12-01

    We tested the feasibility of infra-red (IR) thermography as a tool to survey in situ temperatures in intertidal habitats. We employed this method to describe aspects of thermal ecology for an exposed algal reef in the tropics (O`ahu, Hawai`i). In addition, we compared temperatures of the surrounding habitat as determined by IR thermography and traditional waterproof loggers. Images of reef organisms (6 macroalgae, 9 molluscs, 1 anthozoan, and 2 echinoderms), loggers, and landscapes were taken during two diurnal low tides. Analysis of IR thermographs revealed remarkable thermal complexity on a narrow tropical shore, as habitats ranged from 18.1 to 38.3°C and surfaces of organisms that ranged from 21.1 to 33.2°C. The near 20°C difference between abiotic habitats and the mosaic of temperatures experienced by reef organisms across the shore are similar to findings from temperate studies using specialized longterm loggers. Further, IR thermography captured rapid temperature fluctuations that were related to tidal height and cross-correlated to wave action. Finally, we gathered evidence that tidal species were associated with particular temperature ranges and that two species possess morphological characteristics that limit thermal stress. Loggers provided similar results as thermography but lack the ability to resolve variation in fine-scale spatial and temporal patterns. Our results support the utility of IR thermography in exploring thermal ecology, and demonstrate the steps needed to calibrate data leading to establishment of baseline conditions in a changing and heterogeneous environment.

  4. Digestion of algal biomass for electricity generation in microbial fuel cells.

    PubMed

    Nishio, Koichi; Hashimoto, Kazuhito; Watanabe, Kazuya

    2013-01-01

    Algal biomass serves as a fuel for electricity generation in microbial fuel cells. This study constructed a model consortium comprised of an alga-digesting Lactobacillus and an iron-reducing Geobacter for electricity generation from photo-grown Clamydomonas cells. Total power-conversion efficiency (from Light to electricity) was estimated to be 0.47%.

  5. Effects of anodic oxidation of a substoichiometric titanium dioxide reactive electrochemical membrane on algal cell destabilization and lipid extraction.

    PubMed

    Hua, Likun; Guo, Lun; Thakkar, Megha; Wei, Dequan; Agbakpe, Michael; Kuang, Liyuan; Magpile, Maraha; Chaplin, Brian P; Tao, Yi; Shuai, Danmeng; Zhang, Xihui; Mitra, Somenath; Zhang, Wen

    2016-03-01

    Efficient algal harvesting, cell pretreatment and lipid extraction are the major steps challenging the algal biofuel industrialization. To develop sustainable solutions for economically viable algal biofuels, our research aims at devising innovative reactive electrochemical membrane (REM) filtration systems for simultaneous algal harvesting and pretreatment for lipid extraction. The results in this work particularly demonstrated the use of the Ti4O7-based REM in algal pretreatment and the positive impacts on lipid extraction. After REM treatment, algal cells exhibited significant disruption in morphology and photosynthetic activity due to the anodic oxidation. Cell lysis was evidenced by the changes of fluorescent patterns of dissolved organic matter (DOM) in the treated algal suspension. The lipid extraction efficiency increased from 15.2 ± 0.6 g-lipidg-algae(-1) for untreated algae to 23.4 ± 0.7 g-lipidg-algae(-1) for treated algae (p<0.05), which highlights the potential to couple algal harvesting with cell pretreatment in an integrated REM filtration process.

  6. [Effects of allelochemical EMA isolated from Phragmites communis on algal cell membrane lipid and ultrastructure].

    PubMed

    Li, Feng-min; Hu, Hong-ying; Chong, Yun-xiao; Men, Yu-jie; Guo, Mei-ting

    2007-07-01

    In order to reveal the antialgal mechanisms of allelochemicals, effects of the allelochemical eathyl-2-methyl acetoacetate (EMA) on cell membrane lipid and ultrastructure of Chlorella pyrenoidosa, Microcystis aeruginosa and Chlorella vulagaris were studied in this paper. The lipid fatty acids of the algal membrane were isolated following the Bligh and Dye method and quantified by gas chromatograph/mass spectrometry. The ultrastructure of algal cells was observed with TEM. The results showed that EMA increased the contents of linolenic acid and linolic acid with increment of 14%, while decreased the content of myristic acid and cetylic acid in C. pyrenoidosa, membrane. The content of unsaturated fatty acids C18:1 and C18:2 increased 12% and 10% in M. aeruginosa with the addition of EMA, while the content of saturated fatty acids C18:0 and C16:0 decreased. EMA showed no significant change in the fatty acid composition in C. vulagaris under the experiment condition. EMA broke off cell wall of C. pyrenoidosa and M. aeruginosa. EMA damaged the cell membrane and the inclusion of algal cell leaked out. Nuclear and mitochondrial structure was damaged with the addition of EMA. EMA showed no significant change in the ultrastructure of C. vulgaris.

  7. Ozone exposed epithelial cells modify cocultured natural killer cells

    PubMed Central

    Müller, Loretta; Brighton, Luisa E.

    2013-01-01

    Ozone (O3) causes significant adverse health effects worldwide. Nasal epithelial cells (NECs) are among the first sites within the respiratory system to be exposed to inhaled air pollutants. They recruit, activate, and interact with immune cells via soluble mediators and direct cell-cell contacts. Based on our recent observation demonstrating the presence of natural killer (NK) cells in nasal lavages, the goal of this study was to establish a coculture model of NECs and NK cells and examine how exposure to O3 modifies this interaction. Flow cytometry analysis was used to assess immunophenotypes of NK cells cocultured with either air- or O3-exposed NECs. Our data show that coculturing NK cells with O3-exposed NECs decreased intracellular interferon-γ (IFN-γ), enhanced, albeit not statistically significant, IL-4, and increased CD16 expression on NK cells compared with air controls. Additionally, the cytotoxicity potential of NK cells was reduced after coculturing with O3-exposed NECs. To determine whether soluble mediators released by O3-exposed NECs caused this shift, apical and basolateral supernatants of air- and O3-exposed NECs were used to stimulate NK cells. While the conditioned media of O3-exposed NECs alone did not reduce intracellular IFN-γ, O3 enhanced the expression of NK cell ligands ULBP3 and MICA/B on NECs. Blocking ULBP3 and MICA/B reversed the effects of O3-exposed NECs on IFN-γ production in NK cells. Taken together, these data showed that interactions between NECs and NK cells in the context of O3 exposure changes NK cell activity via direct cell-cell interactions and is dependent on ULBP3/MICA/B expressed on NECs. PMID:23241529

  8. Production of algal biomass (Chlorella vulgaris) using sediment microbial fuel cells.

    PubMed

    Jeon, Hyeon Jin; Seo, Kyu-won; Lee, Sang Hyun; Yang, Yung-Hun; Kumaran, Rangarajulu Senthil; Kim, Sunghyun; Hong, Seok Won; Choi, Yong Su; Kim, Hyung Joo

    2012-04-01

    In this study, a novel algal biomass production method using a sediment microbial fuel cell (SMFC) system was assessed. Under the experimental conditions, CO(2) generation from the SMFC and its rate of increase were found to be dependent on the current generated from the SMFC. However, the CH(4) production rate from the SMFC was inhibited by the generation of current. When Chlorella vulgaris was inoculated into the cathode compartment of the SMFC and current was generated under 10 Ω resistance, biomass production from the anode compartment was observed to be closely associated with the rate of current generation from the SMFC. The experimental results demonstrate that 420 mg/L of algae (dry cell weight) was produced when the current from the SMFC reached 48.5 mA/m(2). Therefore, SMFC could provide a means for producing algal biomass via CO(2) generated by the oxidation of organics upon current generation.

  9. Marine algal fucoxanthin inhibits the metastatic potential of cancer cells.

    PubMed

    Chung, Tae-Wook; Choi, Hee-Jung; Lee, Ji-Yeon; Jeong, Han-Sol; Kim, Cheorl-Ho; Joo, Myungsoo; Choi, Jun-Yong; Han, Chang-Woo; Kim, So-Yeon; Choi, Jae-Sue; Ha, Ki-Tae

    2013-10-04

    Metastasis is major cause of malignant cancer-associated mortality. Fucoxanthin has effect on various pharmacological activities including anti-cancer activity. However, the inhibitory effect of fucoxanthin on cancer metastasis remains unclear. Here, we show that fucoxanthin isolated from brown alga Saccharina japonica has anti-metastatic activity. To check anti-metastatic properties of fucoxanthin, in vitro models including assays for invasion, migration, actin fiber organization and cancer cell-endothelial cell interaction were used. Fucoxanthin inhibited the expression and secretion of MMP-9 which plays a critical role in tumor invasion and migration, and also suppressed invasion of highly metastatic B16-F10 melanoma cells as evidenced by transwell invasion assay. In addition, fucoxanthin diminished the expressions of the cell surface glycoprotein CD44 and CXC chemokine receptor-4 (CXCR4) which play roles in migration, invasion and cancer-endothelial cell adhesion. Fucoxanthin markedly suppressed cell migration in wound healing assay and inhibited actin fiber formation. The adhesion of B16-F10 melanoma cells to the endothelial cells was significantly inhibited by fucoxanthin. Moreover, in experimental lung metastasis in vivo assay, fucoxanthin resulted in significant reduction of tumor nodules. Taken together, we demonstrate, for the first time, that fucoxanthin suppresses metastasis of highly metastatic B16-F10 melanoma cells in vitro and in vivo.

  10. A new approach for the estimation of phytoplankton cell counts associated with algal blooms.

    PubMed

    Nazeer, Majid; Wong, Man Sing; Nichol, Janet Elizabeth

    2017-07-15

    This study proposes a method for estimating phytoplankton cell counts associated with an algal bloom, using satellite images coincident with in situ and meteorological parameters. Satellite images from Landsat Thematic Mapper (TM), Enhanced Thematic Mapper Plus (ETM+), Operational Land Imager (OLI) and HJ-1 A/B Charge Couple Device (CCD) sensors were integrated with the meteorological observations to provide an estimate of phytoplankton cell counts. All images were atmospherically corrected using the Second Simulation of the Satellite Signal in the Solar Spectrum (6S) atmospheric correction method with a possible error of 1.2%, 2.6%, 1.4% and 2.3% for blue (450-520nm), green (520-600nm), red (630-690nm) and near infrared (NIR 760-900nm) wavelengths, respectively. Results showed that the developed Artificial Neural Network (ANN) model yields a correlation coefficient (R) of 0.95 with the in situ validation data with Sum of Squared Error (SSE) of 0.34cell/ml, Mean Relative Error (MRE) of 0.154cells/ml and a bias of -504.87. The integration of the meteorological parameters with remote sensing observations provided a promising estimation of the algal scum as compared to previous studies. The applicability of the ANN model was tested over Hong Kong as well as over Lake Kasumigaura, Japan and Lake Okeechobee, Florida USA, where algal blooms were also reported. Further, a 40-year (1975-2014) red tide occurrence map was developed and revealed that the eastern and southern waters of Hong Kong are more vulnerable to red tides. Over the 40 years, 66% of red tide incidents were associated with the Dinoflagellates group, while the remainder were associated with the Diatom group (14%) and several other minor groups (20%). The developed technology can be applied to other similar environments in an efficient and cost-saving manner.

  11. Image-based monitoring system for green algal Haematococcus pluvialis (Chlorophyceae) cells during culture.

    PubMed

    Ohnuki, Shinsuke; Nogami, Satoru; Ota, Shuhei; Watanabe, Koichi; Kawano, Shigeyuki; Ohya, Yoshikazu

    2013-11-01

    The green microalga Haematococcus pluvialis accumulates the red pigment astaxanthin accompanied by morphological changes under stress conditions, including nutrient depletion, continuous light and high temperature. To investigate the physiological state of the algal cells, we developed the digital image-processing software called HaematoCalMorph. The software automatically outputs 25 single-cell measurements of cell morphology and pigments based on color, bright-field microscopic images. Compared with manual inspection, the output values of cell shape were reliable and reproducible. The estimated pigment content fits the values calculated by conventional methods. Using a random forests classifier, we were able to distinguish flagellated cells from immotile cells and detect their transient appearance in culture. By performing principal components analysis, we also successfully monitored time-dependent morphological and colorimetric changes in culture. Thus, combined with multivariate statistical techniques, the software proves useful for studying cellular responses to various conditions as well as for monitoring population dynamics in culture.

  12. Algal cell disruption using microbubbles to localize ultrasonic energy for biofuel extraction

    NASA Astrophysics Data System (ADS)

    Krehbiel, Joel; Sch, Lance; King, Daniel; Freund, Jonathan

    2014-11-01

    Cell disruption is a critical step in the production of algal-based biofuels, but current mechanical disruption methods require significant energy, typically more than actually available in the cell's oil. We propose and investigate an ultrasound disruption process using ultrasound contrast agents to localize the delivered energy. Experiments in a flow cell with focused ultrasound show a significant benefit. The degree of disruption increases with increasing peak rarefactional ultrasound pressure for pressures between 1.90 and 3.07 MPa and increasing microbubble concentration up to 12 . 5 ×107 bubbles/ml. Estimates suggest the energy of this method is less than one fourth of the energy of other industrial mechanical disruption techniques and comparable with theoretical disruption estimates. The increase in efficiency would make this technique viable for bioenergy applications.

  13. Degradation of algal organic matter using microbial fuel cells and its association with trihalomethane precursor removal.

    PubMed

    Wang, Huan; Liu, Dongmei; Lu, Lu; Zhao, Zhiwei; Xu, Yongpeng; Cui, Fuyi

    2012-07-01

    In order to provide an alternative for removal of algal organic matter (AOM) produced during algal blooms in aquatic environment, microbial fuel cell (MFC) was used to study AOM degradation and its association with THM precursor removal. The chemical oxygen demand (COD) removals in MFCs were 81 ± 6% and 73 ± 3% for AOM from Microcystis aeruginosa (AOM(M)) and Chlorella vulgaris (AOM(C)), respectively. THM precursor was also effectively degraded (AOM(M) 85 ± 2%, AOM(C) 72 ± 4%). The major AOM components (proteins, lipids, and carbohydrates) were obviously removed in MFCs. The contribution of each component to the THM formation potential (THMFP) was obtained based on calculation. The THMFP produced from soluble microbial products was very low. If the energy input during operation process was not considered, MFCs treatment could recover electrical energy of 0.29 ± 0.02 kWh/kg COD (AOM(M)) and 0.35 ± 0.06 kWh/kg COD (AOM(C)).

  14. Characteristic changes in algal organic matter derived from Microcystis aeruginosa in microbial fuel cells.

    PubMed

    Wang, Huan; Lu, Lu; Liu, Dongmei; Cui, Fuyi; Wang, Peng

    2015-11-01

    The objective of this study was to investigate behavior of algal organic matter (AOM) during bioelectrochemical oxidation in microbial fuel cell in terms of compositions and structures. Study revealed that the AOM derived from blue-green algae Microcystis aeruginosa could be degraded more completely (82% COD removal) in microbial fuel cells (MFCs) than by anaerobic fermentation (24% COD removal) in a control reactor without closed-circuit electrode and electricity was produced simultaneously. A variety of techniques were used to characterize the changes in AOM compositions and structures during bioelectrochemical oxidation. The presence of syntrophic interactions between electrochemical active bacteria and fermentative bacteria to degrade large molecular organics into small molecular substances, which could be oxidized by electrode but not by fermentation. The dominant tryptophan protein-like substances, humic acid-like substances and Chlorophyll a in AOM were highly degraded during MFC treatment.

  15. From genome-wide to candidate gene: an investigation of variation at the major histocompatibility complex in common bottlenose dolphins exposed to harmful algal blooms.

    PubMed

    Cammen, Kristina M; Wilcox, Lynsey A; Rosel, Patricia E; Wells, Randall S; Read, Andrew J

    2015-02-01

    The role the major histocompatibility complex (MHC) plays in response to exposure to environmental toxins is relatively poorly understood, particularly in comparison to its well-described role in pathogen immunity. We investigated associations between MHC diversity and resistance to brevetoxins in common bottlenose dolphins (Tursiops truncatus). A previous genome-wide association study investigating an apparent difference in harmful algal bloom (HAB) resistance among dolphin populations in the Gulf of Mexico identified genetic variation associated with survival in close genomic proximity to multiple MHC class II loci. Here, we characterized genetic variation at DQA, DQB, DRA, and DRB loci in dolphins from central-west Florida and the Florida Panhandle, including dolphins that died during HABs and dolphins presumed to have survived HAB exposure. We found that DRB and DQB exhibited patterns of genetic differentiation among geographic regions that differed from neutral microsatellite loci. In addition, genetic differentiation at DRB across multiple pairwise comparisons of live and dead dolphins was greater than differentiation observed at neutral loci. Our findings at these MHC loci did not approach the strength of association with survival previously described for a nearby genetic variant. However, the results provide evidence that selective pressures at the MHC vary among dolphin populations that differ in the frequency of HAB exposure and that the overall composition of DRB variants differs between dolphin survivors and non-survivors of HABs. These results may suggest a potential role of MHC diversity in variable survival of bottlenose dolphins exposed to HABs.

  16. Undifferentiated murine embryonic stem cells used to model the effects of the blue-green algal toxin cylindrospermopsin on preimplantation embryonic cell proliferation.

    PubMed

    Reid, Katherine J; Lang, Kenneth; Froscio, Suzanne; Humpage, Andrew J; Young, Fiona M

    2015-11-01

    Undifferentiated mouse embryonic stem cell (mES) proliferation in vitro resembles aspects of in vivo pre-implantation embryonic development. mES were used to assess the embryo-toxicity of cylindrospermopsin (CYN), a water contaminant with an Australian Drinking Water Guideline (ADWG) of 1 μg/L. mES exposed to 0-1 μg/mL CYN for 24-168 h were subjected to an optimised crystal violet viability assay. mES exposed to retinoic acid ± 1 μg/L CYN differentiated into neural-like cells confirmed by morphological examination and RT-PCR for Oct4, Brachyury and Nestin. The CYN No Observed Effect Concentration (OEC) was 0.5 μg/mL, the Lowest OEC was 1 μg/mL (p < 0.001, n = 3), and the IC50 was 0.86 μg/mL after 24 h. The ADWG 1 μg/L CYN did not affect differentiation or proliferation after 72 h, but decreased proliferation after 168 h (p < 0.05). We conclude that higher algal bloom-associated CYN concentrations have the potential to impair in vivo pre-implantation development, and the mES crystal violet assay has broad application to screening environmental toxins.

  17. The cell recognition model in chlorolichens involving a fungal lectin binding to an algal ligand can be extended to cyanolichens.

    PubMed

    Vivas, M; Sacristán, M; Legaz, M E; Vicente, C

    2010-07-01

    Leptogium corniculatum, a cyanolichen containing Nostoc as photobiont, produces and secretes arginase to culture medium containing arginine. This secreted arginase was pre-purified by affinity chromatography on beads of activated agarose to which a polygalactosylated urease, purified from Evernia prunastri, was attached. Arginase was eluted from the beads with 50 mm alpha-d-galactose. The eluted arginase binds preferentially to the cell surface of Nostoc isolated from this lichen thallus, although it is also able to bind, to some extent, to the cell surface of the chlorobiont isolated from E. prunastri. Previous studies in chlorolichens have shown that a fungal lectin that develops subsidiary arginase activity can be a factor in recognition of compatible algal cells through binding to a polygalactosylated urease, which acts as a lectin ligand in the algal cell wall. Our experiments demonstrate that this model can now be extended to cyanolichens.

  18. Simultaneous wastewater treatment, electricity generation and biomass production by an immobilized photosynthetic algal microbial fuel cell.

    PubMed

    He, Huanhuan; Zhou, Minghua; Yang, Jie; Hu, Youshuang; Zhao, Yingying

    2014-05-01

    A photosynthetic algal microbial fuel cell (PAMFC) was constructed by the introduction of immobilized microalgae (Chlorella vulgaris) into the cathode chamber of microbial fuel cells to fulfill electricity generation, biomass production and wastewater treatment. The immobilization conditions, including the concentration of immobilized matrix, initial inoculation concentration and cross-linking time, were investigated both for the growth of C. vulgaris and power generation. It performed the best at 5 % sodium alginate and 2 % calcium chloride as immobilization matrix, initial inoculation concentration of 10(6) cell/mL and cross-linking time of 4 h. Our findings indicated that C. vulgaris immobilization was an effective and promising approach to improve the performance of PAMFC, and after optimization the power density and Coulombic efficiency improved by 258 and 88.4 %, respectively. Important parameters such as temperature and light intensity were optimized on the performance. PAMFC could achieve a COD removal efficiency of 92.1 %, and simultaneously the maximum power density reached 2,572.8 mW/m(3) and the Coulombic efficiency was 14.1 %, under the light intensity of 5,000 lux and temperature at 25 °C.

  19. Renewable sustainable biocatalyzed electricity production in a photosynthetic algal microbial fuel cell (PAMFC).

    PubMed

    Strik, David P B T B; Terlouw, Hilde; Hamelers, Hubertus V M; Buisman, Cees J N

    2008-12-01

    Electricity production via solar energy capturing by living higher plants and microalgae in combination with microbial fuel cells are attractive because these systems promise to generate useful energy in a renewable, sustainable, and efficient manner. This study describes the proof of principle of a photosynthetic algal microbial fuel cell (PAMFC) based on naturally selected algae and electrochemically active microorganisms in an open system and without addition of instable or toxic mediators. The developed solar-powered PAMFC produced continuously over 100 days renewable biocatalyzed electricity. The sustainable performance of the PAMFC resulted in a maximum current density of 539 mA/m2 projected anode surface area and a maximum power production of 110 mW/m2 surface area photobioreactor. The energy recovery of the PAMFC can be increased by optimization of the photobioreactor, by reducing the competition from non-electrochemically active microorganisms, by increasing the electrode surface and establishment of a further-enriched biofilm. Since the objective is to produce net renewable energy with algae, future research should also focus on the development of low energy input PAMFCs. This is because current algae production systems have energy inputs similar to the energy present in the outcoming valuable products.

  20. Sequestration of CO2 discharged from anode by algal cathode in microbial carbon capture cells (MCCs).

    PubMed

    Wang, Xin; Feng, Yujie; Liu, Jia; Lee, He; Li, Chao; Li, Nan; Ren, Nanqi

    2010-08-15

    Due to increased discharge of CO(2) is incurring problems, CO(2) sequestration technologies require substantial development. By introducing anodic off gas into an algae grown cathode (Chlorella vulgaris), new microbial carbon capture cells (MCCs) were constructed and demonstrated here to be an effective technology for CO(2) emission reduction with simultaneous voltage output without aeration (610+/-50 mV, 1000 Omega). Maximum power densities increased from 4.1 to 5.6 W/m(3) when the optical density (OD) of cathodic algae suspension increased from 0.21 to 0.85 (658 nm). Compared to a stable voltage of 706+/-21 mV (1000 Omega) obtained with cathodic dissolved oxygen (DO) of 6.6+/-1.0 mg/L in MCC, voltage outputs decreased from 654 to 189 mV over 70 h in the control reactor (no algae) accompanied with a decrease in DO from 7.6 to 0.9 mg/L, indicating that cathode electron acceptor was oxygen. Gas analysis showed that all the CO(2) generated from anode was completely eliminated by catholyte, and the soluble inorganic carbon was further converted into algal biomass. These results showed the possibility of a new method for simultaneous carbon fixing, power generation and biodiesel production during wastewater treatment without aeration.

  1. Optical performance of exposed solar cell covers

    NASA Astrophysics Data System (ADS)

    Allen, Thomas H.; Hichwa, Bryant P.; Selee, Steven R.; Dodds, Jerry; Long, Greg S.

    1992-01-01

    This paper discusses the characterization results of samples flown on the Long Duration Exposure Facility (LDEF). These samples included both coated and uncoated fused silica and ceria glass substrates used in the manufacture of solar cell covers. The coatings comprised a single-layer magnesium fluoride antireflection coating and an all-dielectric high-reflector multilayer coating centered at 350 nm. Samples were mounted on both the leading and trailing surfaces of the LDEF for exposure to the environment of space. The optical properties of the coatings will be compared to control samples which were stored on the ground during the LDEF Mission. Results of Auger Electron Spectroscopy and Rutherford Backscatter Spectroscopy measurements made on several of the coatings will be presented to explain the effects of space on the chemical composition of the coatings.

  2. Optical performance of exposed solar cell covers

    NASA Technical Reports Server (NTRS)

    Hichwa, Bryant P.; Selee, Steven R.; Dodds, Jerry; Long, Greg S.

    1991-01-01

    The characterization results of samples flown on the Long Duration Exposure Facility (LDEF) are discussed. These samples included both coated and uncoated fused silica and ceria glass substrates used in the manufacture of solar cell covers. The coatings comprised a single-layer magnesium fluoride antireflection coating and an all-dielectric high-reflector multilayer coating centered at 350 nm. Samples were mounted on both the leading and trailing surfaces of the LDEF for exposure to the environment of space. The optical properties of the coatings will be compared to control samples which were stored on the ground during the LDEF Mission. Results of Auger Electron Spectroscopy and Rutherford Backscatter Spectroscopy measurements made on several of the coatings are presented to explain the effects of space on the chemical composition of the coatings.

  3. Pitfalls, artefacts and open questions in chlorophyll thermoluminescence of leaves or algal cells.

    PubMed

    Ducruet, Jean-Marc

    2013-07-01

    Thermoluminescence of intact photosynthetic organisms, leaves or algal cells, raises specific problems. The constitutive S2/3Q B (-) B bands constitute major probes of the state of photosystem II in vivo. The presence of a dark-stable acidic lumen causes a temperature downshift of B bands, specially the S3 B band, providing a lumen pH indicator. This is accompanied by a broadening of the S3 B band that becomes an envelope of elementary B bands. The occasional AT, Q and C bands are briefly examined in an in vivo context. It is emphasized that freezing below the nucleation temperature is not necessary for physiological studies, but a source of artefacts, hence should be avoided. In intact photosynthetic structures, a dark-electron transfer from stroma reductants to the quinonic acceptors of photosystem II via the cyclic/chlororespiratory pathways, strongly stimulated by moderate warming, gives rise to the afterglow (AG) luminescence emission that reflects chloroplast energy status. The decomposition of complex TL signals into elementary bands is necessary to determine the maximum temperature T m and the area of each of them. A comparison of TL signals after 1 flash and 2 flashes prevents from confusing the three main bands observed in vivo, i.e. the S2 and S3 B bands and the AG band. Finally, the thermoluminescence bands arising sometimes above 50 °C are mentioned. The basic principles of (thermo)luminescence established on isolated thylakoids should not be applied directly without a careful examination of in vivo conditions.

  4. Secreted arginases from phylogenetically farrelated lichen species act as cross-recognition factors for two different algal cells.

    PubMed

    Legaz, María-Estrella; Fontaniella, Blanca; Millanes, Ana-María; Carlos, Vicente

    2004-08-01

    Purified arginases secreted from Evernia prunastri and Xanthoria parietina thalli hydrolyze arginine in a Mn2+ -dependent reaction. Ca2+ cannot replace Mn2+, but its addition to reaction mixtures in the presence of Mn2+ significantly inhibited arginase activity. Arginases from both lichen species also show lectin function, binding to the cell wall of both homologous and heterologous algae. Such binding is enhanced by both Ca2+ and Mn2+ and results in cytoagglutination, which is counteracted by alpha-D-galactose. A putative ligand for these lectins consists of a glycosylated urease, the polysaccharide moiety of which is uniquely composed of alpha-D-galactose. Binding of lectins inhibits its enzymatic activity, which is recovered after desorption of the lectin with alpha-D-galactose. Urease is also eluted from arginase-agarose columns by using alpha-D-galactose as eluent. Data demonstrate ligand-dependent retention of the fungal lectin on the algal cell surface and this is consistent with a model of recognition of compatible algae, through which algal cells would form a lichen with a lectin-secreting fungus only when these cells contain the specific ligand for the lectin in their cell walls. This is, lectin binding is used as a mechanism for ensuring specificity in the association.

  5. Algal-CAMs: isoforms of a cell adhesion molecule in embryos of the alga Volvox with homology to Drosophila fasciclin I.

    PubMed

    Huber, O; Sumper, M

    1994-09-15

    Proof that plants possess homologs of animal adhesion proteins is lacking. In this paper we describe the generation of monoclonal antibodies that interfere with cell-cell contacts in the 4-cell embryo of the multicellular alga Volvox carteri, resulting in a hole between the cells. The number of following cell divisions is reduced and the cell division pattern is altered drastically. Antibodies given at a later stage of embryogenesis specifically inhibit inversion of the embryo, a morphogenetic movement that turns the embryo inside out. Immunofluorescence microscopy localizes the antigen (Algal-CAM) at cell contact sites of the developing embryo. Algal-CAM is a protein with a three-domain structure: an N-terminal extensin-like domain characteristic for plant cell walls and two repeats with homology to fasciclin I, a cell adhesion molecule involved in the neuronal development of Drosophila. Alternatively spliced variants of Algal-CAM mRNA were detected that are produced under developmental control. Thus, Algal-CAM is the first plant homolog of animal adhesion proteins.

  6. Black silicon SERS substrate: effect of surface morphology on SERS detection and application of single algal cell analysis.

    PubMed

    Deng, Yu-Luen; Juang, Yi-Je

    2014-03-15

    In this study, we have investigated the effect of the surface morphology of the black silicon substrate on surface enhanced Raman spectroscopy (SERS) and explored its application of single algal cell detection. By adjusting the O2 and SF6 flow rates in the cryogenic plasma etching process, different surface morphologies of the black silicon substrate was produced without performing the lithographic process. It was found the Raman signals were better enhanced as the tip density of the black silicon substrate increased. In addition, as the thickness of the deposited gold layer increased, the SERS effect increased as well, which could be owing to the generation of more hot spots by bridging individual silicon tips through deposition of gold layer. For the black silicon substrate with tip density of 30 tips/μm(2) and covered by 400 nm deposited gold layer, the detection limit of 10 fM R6G solution concentration with uniform SERS effect across the substrate was achieved. Furthermore, detection of individual algal cell (Chlorella vulgaris) was performed at the SERS substrate as fabricated and the Raman signals of carotenoid and lipid were substantially enhanced.

  7. Potassium ion fluxes in corneal epithelial cells exposed to UVB

    PubMed Central

    Ubels, John L.; Van Dyken, Rachel E.; Louters, Julienne R.; Schotanus, Mark P.; Haarsma, Loren D.

    2011-01-01

    The goal of this study was to investigate the efflux of K+ from human corneal limbal epithelial cells (HCLE) exposed to ambient levels of UVB, which is known to cause apoptosis, and to examine the effect of K+ channel blockers on loss of potassium induced by UVB. HCLE cells were exposed to 100–200 mJ/cm2 UVB, followed by incubation in culture media with 5.5 – 100 mM K+, BDS-1, Ba2+ or ouabain. To measure intracellular cations, cells were washed in 280 mM sucrose and lysed in DI water. K+ and Na+ levels in lysates were measured by ion chromatography. HCLE cells showed maximal loss of [K+]i 10 minutes after exposure to UVB and 5.5 mM K+ media, with recovery of normal K+ levels after 90 minutes. Treatment with 1 µM BDS-1 following UVB exposure reduced the loss of [K+]i retained by HCLE cells. Exposure to 0.1–5 mM Ba2+ inhibited UVB-induced K+ loss in a time and dose dependent manner. These results confirm that blocking K+ channels in HCLE cells exposed to UVB prevents efflux of K+, confirming that UVB activates K+ channels in these cells. Electrophysiology data shows that K+ channels remain highly active at least 90 minutes after UVB exposure. HCLE cells exposed to UVB and incubated 0.01–1µM ouabain did not recover from UVB-induced K+ loss. These data suggest that the Na/K pump may act to restore [K+]i to control levels in HCLE cells following UVB exposure and that the pump is not damaged by exposure to UVB. Incubation of HCLE cells exposed to UVB in medium with 25–100mM K+ media prevented K+ efflux at extracellular concentrations as low as 25mM (the concentration in tear fluid), maintaining control levels of [K+]i. In all experiments inward fluxes and intracelluar Na+ levels mirrored K+ changes, albeit at the expected lower concentrations. The prevention of UVB-induced K+i loss by 25 mM K+o is consistent with the possible contribution of the relatively high K+ concentration in tears to protection of the corneal epithelium from ambient UVB. PMID:21377460

  8. Mammalian cells exposed to ionizing radiation: Structural and biochemical aspects.

    PubMed

    Sabanero, Myrna; Azorín-Vega, Juan Carlos; Flores-Villavicencio, Lérida Liss; Castruita-Dominguez, J Pedro; Vallejo, Miguel Angel; Barbosa-Sabanero, Gloria; Cordova-Fraga, Teodoro; Sosa-Aquino, Modesto

    2016-02-01

    Acute or chronic exposure to ionizing radiation is a factor that may be hazardous to health. It has been reported that exposure to low doses of radiation (less than 50 mSv/year) and subsequently exposure to high doses produces greater effects in people. It has been reported that people who have been exposed to low doses of radiation (less than 50 mSv/year) and subsequently are exposed to high doses, have greater effects. However, at a molecular and biochemical level, it is an unknown alteration. This study, analyzes the susceptibility of a biological system (HeLa ATCC CCL-2 human cervix cancer cell line) to ionizing radiation (6 and 60 mSv/90 s). Our research considers multiple variables such as: total protein profile, mitochondrial metabolic activity (XTT assay), cell viability (Trypan blue exclusion assay), cytoskeleton (actin microfilaments), nuclei (DAPI), and genomic DNA. The results indicate, that cells exposed to ionizing radiation show structural alterations in nuclear phenotype and aneuploidy, further disruption in the tight junctions and consequently on the distribution of actin microfilaments. Similar alterations were observed in cells treated with a genotoxic agent (200 μM H2O2/1h). In conclusion, this multi-criteria assessment enables precise comparisons of the effects of radiation between various line cells. However, it is necessary to determine stress markers for integration of the effects of ionizing radiation.

  9. Comparative genomic hybridization study of arsenic-exposed and non-arsenic-exposed urinary transitional cell carcinoma

    SciTech Connect

    Hsu, L.-I; Chiu, Allen W.; Pu, Y.-S.; Wang, Y.-H.; Huan, Steven K.; Hsiao, C.-H.; Hsieh, F.-I; Chen, C.-J.

    2008-03-01

    To compare the differences in DNA aberrations between arsenic-exposed and non-arsenic-exposed transitional cell carcinoma (TCC), we analyzed 19 arsenic-exposed and 29 non-arsenic-exposed urinary TCCs from Chi-Mei Hospital using comparative genomic hybridization. DNA aberrations were detected in 42 TCCs including 19 arsenic-exposed and 23 non-arsenic-exposed TCCs. Arsenic-exposed TCCs had more changes than unexposed TCCs (mean {+-} SD, 6.6 {+-} 2.9 vs. 2.9 {+-} 2.2). Arsenic exposure was significantly associated with the number of DNA aberrations after adjustment for tumor stage, tumor grade and cigarette smoking in multiple regression analysis. The most frequent DNA gains, which were strikingly different between arsenic-exposed and non-arsenic-exposed TCCs, included those at 1p, 4p, 4q and 8q. A much higher frequency of DNA losses in arsenic-exposed TCCs compared with non-arsenic-exposed TCCs was observed in 10q, 11p and 17p. Chromosomal loss in 17p13 was associated not only with arsenic exposure, but also with tumor stage and grade. The p53 immunohistochemistry staining showed that chromosome 17p13 loss was associated with either p53 no expression (25%) or p53 overexpression (75%). The findings suggest that long-term arsenic exposure may increase the chromosome abnormality in TCC, and 17p loss plays an important role in arsenic-induced urinary carcinogenesis.

  10. The efficiency of photovoltaic cells exposed to pulsed laser light

    NASA Technical Reports Server (NTRS)

    Lowe, R. A.; Landis, G. A.; Jenkins, P.

    1993-01-01

    Future space missions may use laser power beaming systems with a free electron laser (FEL) to transmit light to a photovoltaic array receiver. To investigate the efficiency of solar cells with pulsed laser light, several types of GaAs, Si, CuInSe2, and GaSb cells were tested with the simulated pulse format of the induction and radio frequency (RF) FEL. The induction pulse format was simulated with an 800-watt average power copper vapor laser and the RF format with a frequency-doubled mode-locked Nd:YAG laser. Averaged current vs bias voltage measurements for each cell were taken at various optical power levels and the efficiency measured at the maximum power point. Experimental results show that the conversion efficiency for the cells tested is highly dependent on cell minority carrier lifetime, the width and frequency of the pulses, load impedance, and the average incident power. Three main effects were found to decrease the efficiency of solar cells exposed to simulated FEL illumination: cell series resistance, LC 'ringing', and output inductance. Improvements in efficiency were achieved by modifying the frequency response of the cell to match the spectral energy content of the laser pulse with external passive components.

  11. Chromosome aberrations in ataxia telangiectasia cells exposed to heavy ions

    NASA Astrophysics Data System (ADS)

    Kawata, T.; Cucinotta, F.; George, K.; Wu, H.; Shigematsu, N.; Furusawa, Y.; Uno, T.; Isobe, K.; Ito, H.

    Understanding of biological effects of heavy ions is important to assess healt h risk in space. One of the most important issues may be to take into account individual susceptibility. Ataxia telangiectasia (A-T) cells are known to exhibit abnormal responses to radiations but the mechanism of hyper radiosensitivity of A-T still remains unknown. We report chromosome aberrations in normal human fibroblasts and AT fibroblasts exposed to low- and high-LET radiations. A chemical-induced premature chromosome condensation (PCC) technique combined with chromosome- painting technique was applied to score chromosome aberrations in G2/M-phase cells. Following gamma irradiation, GM02052 cells were approximately 5 times more sensitive to g-rays than AG1522 cells. GM02052 cells had a much higher frequency of deletions and misrejoining than AG1522 cells. When the frequency of complex type aberrations was compared, GM02052 cells showed more than 10 times higher frequency than AG1522 cells. The results will be compared with those obtained from high-LET irradiations.

  12. Fueling Future with Algal Genomics

    SciTech Connect

    Grigoriev, Igor

    2012-07-05

    Algae constitute a major component of fundamental eukaryotic diversity, play profound roles in the carbon cycle, and are prominent candidates for biofuel production. The US Department of Energy Joint Genome Institute (JGI) is leading the world in algal genome sequencing (http://jgi.doe.gov/Algae) and contributes of the algal genome projects worldwide (GOLD database, 2012). The sequenced algal genomes offer catalogs of genes, networks, and pathways. The sequenced first of its kind genomes of a haptophyte E.huxleyii, chlorarachniophyte B.natans, and cryptophyte G.theta fill the gaps in the eukaryotic tree of life and carry unique genes and pathways as well as molecular fossils of secondary endosymbiosis. Natural adaptation to conditions critical for industrial production is encoded in algal genomes, for example, growth of A.anophagefferens at very high cell densities during the harmful algae blooms or a global distribution across diverse environments of E.huxleyii, able to live on sparse nutrients due to its expanded pan-genome. Communications and signaling pathways can be derived from simple symbiotic systems like lichens or complex marine algae metagenomes. Collectively these datasets derived from algal genomics contribute to building a comprehensive parts list essential for algal biofuel development.

  13. Cloning assay thresholds on cells exposed to ultrafast laser pulses

    NASA Astrophysics Data System (ADS)

    Koenig, Karsten; Riemann, Iris; Fischer, Peter; Becker, Thomas P.; Oehring, Hartmut; Halbhuber, Karl-Juergen

    1999-06-01

    The influence of the peak power, laser wavelength and the pulse duration of near infrared (NIR) ultrashort laser pulses on the reproduction behavior of Chinese hamster ovary (CHO) cells has been studied. In particular we determined the cloning efficiency of single cell pairs after exposure to ultrashort laser pulses with an intensity in the range of GW/cm2 and TW/cm2. A total of more than 3500 non- labeled cells were exposed to a highly focused scanning beam of a multiphoton laser microscope with 60 microsecond pixel dwell time per scan. The beam was provided by a tunable argon ion laser pumped mode-locked 76 MHz Titanium:Sapphire laser as well as by a compact solid-state laser based system (Vitesse) at a fixed wavelength of 800 nm. Pulse duration (tau) was varied in the range of 100 fs to 4 ps by out-of-cavity pulse- stretching units consisting of SF14 prisms and blazed gratings. Within an optical (laser power) window CHO cells could be scanned for hours without severe impact on reproduction behavior, morphology and vitality. Ultrastructural studies reveal that mitochondria are the major targets of intense destructive laser pulses. Above certain laser power P thresholds, CHO cells started to delay or failed to undergo cell division and, in part, to develop uncontrolled cell growth (giant cell formation). The damage followed a P2/(tau) relation which is typical for a two-photon excitation process. Therefore, cell damage was found to be more pronounced at shorter pulses. Due to the same P2/(tau) relation for the efficiency of fluorescence excitation, two- photon microscopy of living cells does not require extremely short femtosecond laser pulses nor pulse compression units. Picosecond as well as femtosecond layers can be used as efficient light sources in safe two photon fluorescence microscopy. Only in three photon fluorescence microscopy, femtosecond laser pulses are advantageous over picosecond pulses.

  14. Cloning assay thresholds on cells exposed to ultrafast laser pulses

    NASA Astrophysics Data System (ADS)

    Koenig, Karsten; Riemann, Iris; Fischer, Peter; Becker, Thomas P.; Oehring, Hartmut; Halbhuber, Karl-Juergen

    1999-06-01

    The influence of the peak power, laser wavelength and the pulse duration of near infrared ultrashort laser pulses on the reproduction behavior of Chinese hamster ovary (CHO) cells has been studied. In particular, we determined the cloning efficiency of single cell pairs after exposure to ultrashort laser pulses with an intensity in the range of GW/cm2 and TW/cm2. A total of more than 3500 non- labeled cells were exposed to a highly focused scanning beam of a multiphoton laser microscope with 60 microsecond(s) pixel dwell time per scan. The beam was provided by a tunable argon ion laser pumped mode-locked 76 MHz Titanium:Sapphire laser as well as by a compact solid-state laser based system (Vitesse) at a fixed wavelength of 800 nm. Pulse duration (tau) was varied in the range of 100 fs to 4 ps by out-of- cavity pulse-stretching units consisting of SF14 prisms and blazed gratings. Within an optical (laser power) window CHO cells could be scanned for hours without severe impact on reproduction behavior, morphology and vitality. Ultrastructural studies reveal that mitochondria are the major targets of intense destructive laser pulses. Above certain laser power P thresholds, CHO cells started to delay or failed to undergo cell division and, in part, to develop uncontrolled cell growth (giant cell formation). The damage followed a P2/(tau) relation which is typical for a two- photon excitation process. Therefore, cell damage was found to be more pronounced at shorter pulses. Due to the same P2/(tau) relation for the efficiency of fluorescence excitation, two-photon microscopy of living cells does not require extremely short femtosecond laser pulses nor pulse compression units. Picosecond as well as femtosecond lasers can be used as efficient light sources in safe two photon fluorescence microscopy. Only in three photon fluorescence microscopy, femtosecond laser pulses are advantageous over picosecond pulses.

  15. Algal biofuels.

    PubMed

    Razeghifard, Reza

    2013-11-01

    The world is facing energy crisis and environmental issues due to the depletion of fossil fuels and increasing CO2 concentration in the atmosphere. Growing microalgae can contribute to practical solutions for these global problems because they can harvest solar energy and capture CO2 by converting it into biofuel using photosynthesis. Microalgae are robust organisms capable of rapid growth under a variety of conditions including in open ponds or closed photobioreactors. Their reduced biomass compounds can be used as the feedstock for mass production of a variety of biofuels. As another advantage, their ability to accumulate or secrete biofuels can be controlled by changing their growth conditions or metabolic engineering. This review is aimed to highlight different forms of biofuels produced by microalgae and the approaches taken to improve their biofuel productivity. The costs for industrial-scale production of algal biofuels in open ponds or closed photobioreactors are analyzed. Different strategies for photoproduction of hydrogen by the hydrogenase enzyme of green algae are discussed. Algae are also good sources of biodiesel since some species can make large quantities of lipids as their biomass. The lipid contents for some of the best oil-producing strains of algae in optimized growth conditions are reviewed. The potential of microalgae for producing petroleum related chemicals or ready-make fuels such as bioethanol, triterpenic hydrocarbons, isobutyraldehyde, isobutanol, and isoprene from their biomass are also presented.

  16. Cell division in Apicomplexan parasites is organized by a homolog of the striated rootlet fiber of algal flagella.

    PubMed

    Francia, Maria E; Jordan, Carly N; Patel, Jay D; Sheiner, Lilach; Demerly, Jessica L; Fellows, Justin D; de Leon, Jessica Cruz; Morrissette, Naomi S; Dubremetz, Jean-François; Striepen, Boris

    2012-01-01

    Apicomplexa are intracellular parasites that cause important human diseases including malaria and toxoplasmosis. During host cell infection new parasites are formed through a budding process that parcels out nuclei and organelles into multiple daughters. Budding is remarkably flexible in output and can produce two to thousands of progeny cells. How genomes and daughters are counted and coordinated is unknown. Apicomplexa evolved from single celled flagellated algae, but with the exception of the gametes, lack flagella. Here we demonstrate that a structure that in the algal ancestor served as the rootlet of the flagellar basal bodies is required for parasite cell division. Parasite striated fiber assemblins (SFA) polymerize into a dynamic fiber that emerges from the centrosomes immediately after their duplication. The fiber grows in a polarized fashion and daughter cells form at its distal tip. As the daughter cell is further elaborated it remains physically tethered at its apical end, the conoid and polar ring. Genetic experiments in Toxoplasma gondii demonstrate two essential components of the fiber, TgSFA2 and 3. In the absence of either of these proteins cytokinesis is blocked at its earliest point, the initiation of the daughter microtubule organizing center (MTOC). Mitosis remains unimpeded and mutant cells accumulate numerous nuclei but fail to form daughter cells. The SFA fiber provides a robust spatial and temporal organizer of parasite cell division, a process that appears hard-wired to the centrosome by multiple tethers. Our findings have broader evolutionary implications. We propose that Apicomplexa abandoned flagella for most stages yet retained the organizing principle of the flagellar MTOC. Instead of ensuring appropriate numbers of flagella, the system now positions the apical invasion complexes. This suggests that elements of the invasion apparatus may be derived from flagella or flagellum associated structures.

  17. Phylogenomic Analyses Indicate that Early Fungi Evolved Digesting Cell Walls of Algal Ancestors of Land Plants.

    PubMed

    Chang, Ying; Wang, Sishuo; Sekimoto, Satoshi; Aerts, Andrea L; Choi, Cindy; Clum, Alicia; LaButti, Kurt M; Lindquist, Erika A; Yee Ngan, Chew; Ohm, Robin A; Salamov, Asaf A; Grigoriev, Igor V; Spatafora, Joseph W; Berbee, Mary L

    2015-05-14

    As decomposers, fungi are key players in recycling plant material in global carbon cycles. We hypothesized that genomes of early diverging fungi may have inherited pectinases from an ancestral species that had been able to extract nutrients from pectin-containing land plants and their algal allies (Streptophytes). We aimed to infer, based on pectinase gene expansions and on the organismal phylogeny, the geological timing of the plant-fungus association. We analyzed 40 fungal genomes, three of which, including Gonapodya prolifera, were sequenced for this study. In the organismal phylogeny from 136 housekeeping loci, Rozella diverged first from all other fungi. Gonapodya prolifera was included among the flagellated, predominantly aquatic fungal species in Chytridiomycota. Sister to Chytridiomycota were the predominantly terrestrial fungi including zygomycota I and zygomycota II, along with the ascomycetes and basidiomycetes that comprise Dikarya. The Gonapodya genome has 27 genes representing five of the seven classes of pectin-specific enzymes known from fungi. Most of these share a common ancestry with pectinases from Dikarya. Indicating functional and sequence similarity, Gonapodya, like many Dikarya, can use pectin as a carbon source for growth in pure culture. Shared pectinases of Dikarya and Gonapodya provide evidence that even ancient aquatic fungi had adapted to extract nutrients from the plants in the green lineage. This implies that 750 million years, the estimated maximum age of origin of the pectin-containing streptophytes represents a maximum age for the divergence of Chytridiomycota from the lineage including Dikarya.

  18. Synthesis of protein in intestinal cells exposed to cholera toxin

    SciTech Connect

    Peterson, J.W.; Berg, W.D. Jr.; Coppenhaver, D.H.

    1987-11-01

    The mechanism by which cyclic adenosine monophosphate (AMP), formed by intestinal epithelial cells in response to cholera toxin, ultimately results in alterations in water and electrolyte transport is poorly understood. Several studies have indicated that inhibitors of transcription or translation block much of the transport of ions and water in the intestine and edema formation in tissue elicited by cholera toxin. Data presented in this study confirmed the inhibitory effects of cycloheximide on cholera toxin-induced fluid accumulation in the rabbit intestinal loop model. Neither cycloheximide nor actinomycin D altered the amount of cyclic AMP that accumulated in intestinal cells and Chinese hamster ovary cells exposed to cholera toxin. An increase in (/sup 3/H) leucine incorporation was readily demonstrable in intestinal epithelial cells from rabbits challenged with Vibrio cholerae. Similarly, intestinal epithelial cells incubated with cholera toxin for 4 hr synthesized substantially more protein than controls as determined by relative incorporation of (/sup 35/S) methionine. Most of the new protein synthesized in response to cholera toxin was membrane associated and of high molecular weight. The possible significance of the toxin-induced protein relative to cholera pathogenesis was discussed.

  19. Algal culture studies for CELSS

    NASA Technical Reports Server (NTRS)

    Radmer, R.; Behrens, P.; Arnett, K.; Gladue, R.; Cox, J.; Lieberman, D.

    1987-01-01

    Microalgae are well-suited as a component of a Closed Environmental Life Support System (CELSS), since they can couple the closely related functions of food production and atmospheric regeneration. The objective was to provide a basis for predicting the response of CELSS algal cultures, and thus the food supply and air regeneration system, to changes in the culture parameters. Scenedesmus growth was measured as a function of light intensity, and the spectral dependence of light absorption by the algae as well as algal respiration in the light were determined as a function of cell concentration. These results were used to test and confirm a mathematical model that describes the productivity of an algal culture in terms of the competing processes of photosynthesis and respiration. The relationship of algal productivity to cell concentration was determined at different carbon dioxide concentrations, temperatures, and light intensities. The maximum productivity achieved by an air-grown culture was found to be within 10% of the computed maximum productivity, indicating that CO2 was very efficiently removed from the gas stream by the algal culture. Measurements of biomass productivity as a function of cell concentration at different light intensities indicated that both the productivity and efficiency of light utilization were greater at higher light intensities.

  20. Polyamines and polyamine biosynthesis in cells exposed to hyperthermia

    SciTech Connect

    Gerner, E.W.; Stickney, D.G.; Herman, T.S.; Fuller, D.J.

    1983-02-01

    The issue of how polyamines act to sensitize cultured cells to the lethal effects of hyperthermia was investigated using Chinese hamster cells which were induced to express thermotolerance. Intracellular levels of these naturally occurring polycations were manipulated in certain situations by treating whole cells with methylglyoxal bis-(guanylhydrazone), an inhibitor of the S-adenosyl-L-methionine decarboxylases. Exogenous spermine as low as 100 ..mu..M in the culture media dramatically sensitized cells expressing thermotolerance to the lethal effects of subsequent 42/sup 0/C exposures. When thermotolerance was differentially induced in cultures exposed to 42.4/sup 0/C by varying the rate of heating from 37 to 42.4/sup 0/C, the most resistant cells and the highest levels of intracellular spermidine and spermine. This finding was explainable in part by the observation that the putrescine-dependent S-adenosyl-L-methionine decarboxylase activity was minimally affected in cells expressng the greatest degree of thermotolerance. When this enzyme activity was inhibited by drug, lowered intracellular polyamine levels did not correspond with subsequent survival responses to heat. Interestingly, cultures treated with methylglyoxal bis-(guanylhydrazone) 24 hr previous to heat exposure showed a reduced capacity to express rate of heating-induced thermotolerance. Together, these results demonstrate that the polyamines, especially spermidine and spermine, enhance hyperthermia-induced cell killing by some mechanism involving the plasma membrane. Further, our data suggest that methylglyoxal bis-(guanylhydrazone) can act to affect thermal responses by a mechanism(s) other than modification of intracellular polyamine levels.

  1. Harmful Algal Bloom Webinar

    EPA Pesticide Factsheets

    The problem is complex. Excessive nitrogen and phosphorous levels can cause harmful algal blooms. Different algal/cyanobacteria strains bloom under different conditions. Different strains produce different toxins at varying amounts.

  2. Integrated Bacillus sp. immobilized cell reactor and Synechocystis sp. algal reactor for the treatment of tannery wastewater.

    PubMed

    Sekaran, G; Karthikeyan, S; Nagalakshmi, C; Mandal, A B

    2013-01-01

    The wastewater discharged from leather industries lack biodegradability due to the presence of xenobiotic compounds. The primary clarification and aerobic treatment in Bacillus sp. immobilized Chemo Autotrophic Activated Carbon Oxidation (CAACO) reactor removed considerable amount of pollution parameters. The residual untreated organics in the wastewater was further treated in algal batch reactor inoculated with Synechocystis sp. Sodium nitrate, K(2)HPO(4), MgSO(4).7H(2)O, NH(4)Cl, CaCl(2)·2H(2)O, FeCl(3) (anhydrous), and thiamine hydrochloride, rice husk based activated carbon (RHAC), immobilization of Bacillus sp. in mesoporous activated carbon, sand filter of dimensions diameter, 6 cm and height, 30 cm; and the CAACO reactor of dimensions diameter, 5.5 cm and height, 30 cm with total volume 720 ml, and working volume of 356 ml. In the present investigation, the CAACO treated tannery wastewater was applied to Synechocystis sp. inoculated algal batch reactor of hydraulic residence time 24 h. The BOD(5), COD, and TOC of treated wastewater from algal batch reactor were 20 ± 7, 167 ± 29, and 78 ± 16 mg/l respectively. The integrated CAACO system and Algal batch reactor was operated for 30 days and they accomplished a cumulative removal of BOD(5),COD, TOC, VFA and sulphide as 98 %, 95 %, 93 %, 86 %, and 100 %, respectively. The biokinetic constants for the growth of algae in the batch reactor were specific growth rate, 0.095(day(-1)) and yield coefficient, 3.15 mg of algal biomass/mg of COD destructed. The degradation of xenobiotic compounds in the algal batch reactor was confirmed through HPLC and FT-IR techniques. The integrated CAACO-Algal reactor system established a credible reduction in pollution parameters in the tannery wastewater. The removal mechanism is mainly due to co-metabolism between algae and bacterial species and the organics were completely metabolized rather than by adsorption.

  3. EFFECTS OF MARINE ALGAL TOXINS ON THERMOREGULATION IN MICE.

    EPA Science Inventory

    Hypothermia is often seen in mice and rats exposed acutely to marine algal toxins, but the mechanism of action of these toxins on thermoregulation is not well understood. Our laboratory has assessed the thermoregulatory mechanisms of two marine algal toxins, maitotoxin and brevet...

  4. Expression of functionally relevant cell surface markers in dibutyltin-exposed human natural killer cells.

    PubMed

    Odman-Ghazi, Sabah O; Hatcher, Frank; Whalen, Margaret M

    2003-07-25

    Butyltin (BT) compounds are known for their worldwide contamination. Dibutyltin (DBT) is used as a stabilizer in plastic products, and as a deworming agent in poultry. Poultry products have been shown to contain measurable levels of DBT. Drinking water has also been reported to contain BTs due to leaching from PVC pipes. We, and others, have found measurable levels of DBT in human blood. BTs appear to increase the risk of cancer and other viral infections in exposed individuals. In previous studies we have shown that the tumor killing function of natural killer (NK) lymphocytes was greatly diminished after as little as a 1 h exposure to DBT and the inhibition continued even after removal of the compound. We also showed that there was a significant decrease in NK cell lysis of K562 target cells after an exposure to 1.5 microM DBT for 24 h. This 24 h exposure also decreased the ability of NK cells to bind to tumor cells. Loss of binding function was not seen when NK cells were exposed to 5-10 microM DBT for 1 h. However, NK cells exposed to 5 microM DBT for 1 h and then incubated in DBT-free media for 24, 48, or 96 h, showed a significant loss of tumor-binding function within 24 h. The effects of DBT exposure on seven cell surface molecules that are involved in NK-cell interactions with target cells were investigated. The results indicated that the exposure of NK cells to 1.5 microM DBT for 24 h decreased the expression of CD2, CD11a, CD16, CD11c. There was no decrease in expression of any of the markers studied when NK cells were exposed to 5 microM DBT for 1 h, consistent with the fact that a 1-h exposure had no effect on the ability of NK cells to bind tumor cells. However, when NK cells were exposed to 5 microM DBT for 1 h followed by 24, 48 or 96 h incubations in DBT-free media there was decreased expression of several of the cells surface molecules with the most dramatic decreases being in CD16 and CD56.

  5. Prechlorination of algae-laden water: The effects of transportation time on cell integrity, algal organic matter release, and chlorinated disinfection byproduct formation.

    PubMed

    Qi, Jing; Lan, Huachun; Liu, Ruiping; Miao, Shiyu; Liu, Huijuan; Qu, Jiuhui

    2016-10-01

    The prechlorination-induced algal organic matter (AOM) released from Microcystis aeruginosa (M. aeruginosa) cells has been reported to serve as a source of precursors for chlorinated disinfection byproducts (DBPs). However, previous studies have mainly focused on the precursors either extracted directly from the cell suspension or derived immediately after algal suspension prechlorination. This study aims to investigate the impacts of water transportation time after algal suspension prechlorination on cell integrity, AOM release, and DBP formation during the dissolved phase chlorination. The damage to cell integrity after prechlorination was indicated to depend not only on chlorine dose but also on transportation time. The highest dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) values were observed at 2 mg/L chlorine preoxidation before transportation, but were obtained at 0.4 mg/L chlorine after 480-min simulated transportation. The variation of DON with transportation time was indicated to be mainly influenced by the small molecular weight nitrogenous organic compounds, such as amino acids. Additionally, formation of the corresponding chlorinated carbonaceous disinfection byproducts (C-DBPs) and nitrogenous disinfection byproducts (N-DBPs) during the dissolved phase chlorination showed the same variation tendency as DOC and DON respectively. The highest C-DBP (98.4 μg/L) and N-DBP (5.5 μg/L) values were obtained at 0.4 mg/L chlorine preoxidation after 480-min simulated transportation. Therefore, when prechlorination is applied for algae-laden water pretreatment, not only chlorine dose but also transportation time needs to be considered with regard to their effects on cell integrity, AOM release, and chlorinated DBP formation.

  6. Cell size and the blockage of electron transfer in photosynthesis: proposed endpoints for algal assays and its application to soil alga Chlorococcum infusionum.

    PubMed

    Nam, Sun-Hwa; An, Youn-Joo

    2015-06-01

    This study evaluated multiple endpoints of algal assays to identify sensitive and easy to use endpoints that could be applied to evaluate algal toxicity in metal-polluted soil extracts. Soil algae play an important role in trophic levels; thus, Chlorococcum infusionum was selected as the test species. Soil extracts were used because they might help identify potential soil retention and ecological hazards caused by pollutants that are present in the soil aqueous phase. The multi-endpoints measured were growth yield, photosynthetic activities, and cell viabilities. Nine parameters were measured to evaluate photosynthetic activity; namely, specific energy fluxes per quinone A-reducing photosystem II reaction center (absorption flux, trapped energy flux, electron transport flux, and dissipated energy flux per reaction center), quantum yields (maximum quantum yield of primary photochemistry, quantum yield of electron transport, quantum yield of energy dissipation, and average quantum yield of primary photochemistry), and the blockage of electron transfer from the reaction center to the quinone pool. Cell viability was evaluated by measuring cell size, cell granularity, and the autofluorescence of chlorophyll using flow cytometry. The results showed that heavy metals reduced growth yield, cell viability, and the photosynthetic activity of C. infusionum in soil extracts. Out of the 13 tested endpoints, the blockage of electron transfer from the reaction center to the quinone pool and cell size represented the most sensitive endpoints. We propose that both endpoints should be measured, along with conventional growth yield, to determine the effect of soil pollutants and to lower pollutant concentrations in soils.

  7. Cyanobacteria Toxin and Cell Propagation through Seven Lake Erie Treatment Plants during the 2013 Algal Bloom Season - abstract

    EPA Science Inventory

    Over the past five years, Lake Erie has been experiencing harmful algal blooms (HABs) of progressively increasing severity. Cognizant of the potential health and economic impacts, the United States Environmental Protection Agency’s (USEPA’s) Water Supply and Water Resources Divis...

  8. Tracking the spectroscopic and chromatographic changes of algal derived organic matter in a microbial fuel cell.

    PubMed

    Hur, Jin; Lee, Bo-Mi; Choi, Kwang-Soon; Min, Booki

    2014-02-01

    Changes in the characteristics of algae-derived organic matter (AOM) were examined upon the operation of a microbial fuel cell (MFC) using multiple analytical methods. Temporal variations in the UV absorption and fluorescence excitation-emission matrix of the AOM revealed that less condensed humic-like components and large-sized protein-like fluorescent compounds were preferentially decomposed over the period of electricity generation. They also showed that low UV-absorbing extracellular organic matters (EOM) were produced at the end of the operation. SEC chromatograms demonstrated that smaller-sized UV-absorbing components were initially decomposed, followed by the net production of EOM with an intermediate molecular weight. Fourier transform infrared (FT-IR) spectra showed that proteins and polysaccharides were the two most dominant structures of the AOM in the MFC. Two-dimensional correlation spectroscopy combined with FT-IR provided additional valuable information on the sequential changes of the AOM, which occurred in the order of proteins → acidic functional groups → polysaccharides → amino acids/proteins.

  9. Heterologous activation of the Porphyra tenera HSP70 promoter in Bangiophycean algal cells.

    PubMed

    Hirata, Ryo; Jeong, Won-Joong; Saga, Naotsune; Mikami, Koji

    2011-01-01

    Porphyra has attracted great attention for its biological and industrial importance. However, establishment of a stable nuclear transformation has not yet been achieved in these organisms, which impedes the molecular biological study and the development of a molecular breeding method for them. Toward establishing the stable transformation, we have recently developed an efficient transient gene expression system in Bangiophycean algae, in which the HSP70 promoter from P. tenera (PtHSP70 promoter) was activated heterologously in P. yezoensis cells. Since heterologous promoters are required for homologous recombination-based stable transformation, the identification of heterologously activated promoters is important in establishing a stable transformation system in individual Bangiophycean alga. We here examined the activation of the PtHSP70 promoter using the GC-rich PyGUS reporter system in additional Porphyra and Bangia species. The results indicated that this promoter drove expression of the PyGUS gene efficiently in all examined algae, whereas there was quite low expression of PyGUS by the cauliflower mosaic virus 35S promoter that is widely used as a heterologous promoter in the transformation of green land plants. Therefore, heterologous activation of the PtHSP70 promoter could promote the establishment of the stable transformation system in various kinds of Bangiophycean algae.

  10. Algal Systems for Hydrogen Photoproduction

    SciTech Connect

    Ghirardi, Maria L

    2015-10-08

    The National Renewable Energy Laboratory (NREL), under the guidance of Drs. Michael Seibert (retired, Fellow Emeritus) and Maria Ghirardi (Fellow), led 15 years of research addressing the issue of algal H2 photoproduction. This project resulted in greatly increased rates and yields of algal hydrogen production; increased understanding of the H2 metabolism in the green alga, Chlamydomonas reinhardtii; expanded our knowledge of other physiological aspects relevant to sustained algal photosynthetic H2 production; led to the genetic identification, cloning and manipulation of algal hydrogenase genes; and contributed to a broader, fundamental understanding of the technical and scientific challenges to improving the conversion efficiencies in order to reach the U.S. Department of Energy’s Fuel Cell Technologies Office’s targets. Some of the tangible results are: (i) 64 publications and 6 patents, (ii) international visibility to NREL, (iii) reinvigoration of national and international biohydrogen research, and (iv) research progress that helped stimulate new funding from other DOE and non-DOE programs, including the AFOSR and the DOE Office of Science.

  11. Impaired NK Cell Activation and Chemotaxis toward Dendritic Cells Exposed to Complement-Opsonized HIV-1.

    PubMed

    Ellegård, Rada; Crisci, Elisa; Andersson, Jonas; Shankar, Esaki M; Nyström, Sofia; Hinkula, Jorma; Larsson, Marie

    2015-08-15

    Mucosa resident dendritic cells (DCs) may represent one of the first immune cells that HIV-1 encounters during sexual transmission. The virions in body fluids can be opsonized with complement factors because of HIV-mediated triggering of the complement cascade, and this appears to influence numerous aspects of the immune defense targeting the virus. One key attribute of host defense is the ability to attract immune cells to the site of infection. In this study, we investigated whether the opsonization of HIV with complement (C-HIV) or a mixture of complement and Abs (CI-HIV) affected the cytokine and chemokine responses generated by DCs, as well as their ability to attract other immune cells. We found that the expression levels of CXCL8, CXCL10, CCL3, and CCL17 were lowered after exposure to either C-HIV or CI-HIV relative to free HIV (F-HIV). DCs exposed to F-HIV induced higher cell migration, consisting mainly of NK cells, compared with opsonized virus, and the chemotaxis of NK cells was dependent on CCL3 and CXCL10. NK cell exposure to supernatants derived from HIV-exposed DCs showed that F-HIV induced phenotypic activation (e.g., increased levels of TIM3, CD69, and CD25) and effector function (e.g., production of IFNγ and killing of target cells) in NK cells, whereas C-HIV and CI-HIV did not. The impairment of NK cell recruitment by DCs exposed to complement-opsonized HIV and the lack of NK activation may contribute to the failure of innate immune responses to control HIV at the site of initial mucosa infection.

  12. Structural Impacts on Thallus and Algal Cell Components of Two Lichen Species in Response to Low-Level Air Pollution in Pacific Northwest Forests

    NASA Astrophysics Data System (ADS)

    Ra, Hyung-Shim Y.; Rubin, Laura; Crang, Richard F. E.

    2004-04-01

    Lichens have long been regarded as bioindicators of air pollution, and structural studies typically have indicated negative impacts in highly polluted areas. In this research, Parmelia sulcata and Platismatia glauca were collected from one clean and two polluted sites in the Pacific Northwest forests of the United States to investigate the anatomical and ultrastructural responses of relatively resistant lichens to moderate air pollution. Light microscopy of polluted materials revealed only slight increases in the algal cell proportions of the thallus, and a decrease in the fungal cells of the medulla. Using transmission electron microscopy, increased lipid droplets in the cytoplasm and an increase in the cell wall thickness of the photobionts were found in the polluted lichens. These results were compared with physiological data in which the net carbon uptake did not show any significant differences; however, the total chlorophyll content was heightened in the polluted samples. The increased total chlorophyll content and the absence of any changes in the algal cell proportions of the polluted samples suggest that the photobionts possessed a higher chlorophyll content per unit volume of the photobiont at polluted sites. The results also indicate that lichens have altered their storage allocation in different cellular compartments. This may be a result of symbiotic readjustment(s) between the photobiont and the mycobiont. In comparison with the physiological results from these two species, these changes do not represent damaging effects by low-level air pollution.

  13. Platy algal banks: Modern and ancient

    SciTech Connect

    Brinton, L. )

    1990-05-01

    Plaly algal banks and associated cycles in the lower Ismay zone of the Paradox Formation are exposed along the walls of the San Juan River canyon, southeastern Utah. These complexes closely resemble algal bank reservoirs in the lower Ismay zone of Ismay and Cache, and possibly other Paradox basin fields. Similarities include facies relationships, lateral and vertical textural variations, and early diagenesis. Extensive algal banks exposed along the San Juan canyon generally have flat bases and mound and swale topographic surfaces, and are separated by interbank channels. The surficial mounds have a regular amplitude and wavelength suggesting a hydrologic rather than biologic influence on topography. The banks themselves, however, are believed to be thick, predominantly in-situ accumulations of platy algae. Distribution of algal banks can be mapped on a field scale; mound and swale topographic features may be identified in core on the basis of depositional and early diagenetic characteristics. Halimeda bioherms (Holocene) cover large areas behind the Great Barrier Reef, developing adjacent to the deep passes that separate the individual reefs. These large in-situ accumulations (20-50 m deep) display similar bank geometries, interbank features, topographic features, vertical textural sequence (including porosity type and distribution), and facies relationships to algal banks observed in the outcropping and subsurface Paradox Formation. Although the hydrodynamic and paleobathymetric settings differ markedly between these two examples, analogies between the mounds themselves are very close. The resemblance lends relevance to exploration and development drilling.

  14. X-ray microanalysis of calcium in fixed and in shock-frozen hydrated green algal cells: Mougeotia, Spirogyra and Zygnema

    NASA Astrophysics Data System (ADS)

    Rossbacher, Roland; Wagner, Gottfried; Pallaghy, Charles K.

    1984-04-01

    X-ray microanalysis, widely used for ionic detection in cell tissues, was performed on 0.5 μm thick glutaraldehyde-osmiumtetroxide fixed cell sections. Calcium in a water-insoluble state was found in membrane bound vesicles of about 0.5 μm in diameter. No other cell compartment showed a comparable calcium accumulation. In vivo staining by the fluorescent calcium indicator dye chlorotetracycline revealed a vesicular calcium pattern in Mougeotia matching the results by X-ray microanalysis: a dense population of calcium vesicles is located close to the chloroplast edge where the actin filaments are attached. The data find further support from X-ray microanalysis of shock-frozen hydrated Mougeotia cells and of the closely related green algal cells Spirogyra and Zygnema (Zygnemaceae). X-ray microanalysis as performed in this study seems a reliable tool for the detection of water-insoluble calcium stored by membrane-covered cytoplasmic compartments.

  15. Biliary epithelium and liver B cells exposed to bacteria activate intrahepatic MAIT cells through MR1

    PubMed Central

    Jeffery, Hannah C.; van Wilgenburg, Bonnie; Kurioka, Ayako; Parekh, Krishan; Stirling, Kathryn; Roberts, Sheree; Dutton, Emma E.; Hunter, Stuart; Geh, Daniel; Braitch, Manjit K.; Rajanayagam, Jeremy; Iqbal, Tariq; Pinkney, Thomas; Brown, Rachel; Withers, David R.; Adams, David H.; Klenerman, Paul; Oo, Ye H.

    2016-01-01

    Background & Aims Mucosal-Associated Invariant T (MAIT) cells are innate-like T cells characterised by the invariant TCR-chain, Vα7.2-Jα33, and are restricted by MR1, which presents bacterial vitamin B metabolites. They are important for antibacterial immunity at mucosal sites; however, detailed characteristics of liver-infiltrating MAIT (LI-MAIT) and their role in biliary immune surveillance remain unexplored. Methods The phenotype and intrahepatic localisation of human LI-MAIT cells was examined in diseased and normal livers. MAIT cell activation in response to E. coli-exposed macrophages, biliary epithelial cells (BEC) and liver B cells was assessed with/without anti-MR1. Results Intrahepatic MAIT cells predominantly localised to bile ducts in the portal tracts. Consistent with this distribution, they expressed biliary tropic chemokine receptors CCR6, CXCR6, and integrin αEβ7. LI-MAIT cells were also present in the hepatic sinusoids and possessed tissue-homing chemokine receptor CXCR3 and integrins LFA-1 and VLA-4, suggesting their recruitment via hepatic sinusoids. LI-MAIT cells were enriched in the parenchyma of acute liver failure livers compared to chronic diseased livers. LI-MAIT cells had an activated, effector memory phenotype, expressed α4β7 and receptors for IL-12, IL-18, and IL-23. Importantly, in response to E. coli-exposed macrophages, liver B cells and BEC, MAIT cells upregulated IFN-γ and CD40 Ligand and degranulated in an MR1-dependent, cytokine-independent manner. In addition, diseased liver MAIT cells expressed T-bet and RORγt and the cytokines IFN-γ, TNF-α, and IL-17. Conclusions Our findings provide the first evidence of an immune surveillance effector response for MAIT cells towards BEC in human liver; thus they could be manipulated for treatment of biliary disease in the future. PMID:26743076

  16. Detection of programmed cell death in cells exposed to genotoxic agents using a caspase activation assay.

    PubMed

    Gupta, Madhu; Santra, Madhumita; Koty, Patrick P

    2014-01-01

    Many toxins that individuals are exposed to cause DNA damage. Cells that have sustained DNA damage may attempt to repair the damage prior to replication. However, if a cell has sustained serious damage it cannot repair, it will commit suicide through a genetically regulated programmed cell death (PCD) pathway. Crucial to the ultimate execution of PCD is a family of cysteine proteases called caspases. Activation of these enzymes occurs late enough in the PCD pathway that a cell can no longer avoid cell death, but still earlier than PCD-associated morphological changes or DNA fragmentation. This protocol details a method for using fluorochrome-conjugated caspase inhibitors for the detection of activated caspases in intact cells. The analysis and documentation is performed using fluorescence microscopy.

  17. Cytoplasmic myosin exposed apoptotic cells appear with caspase-3 activation and enhance CLL cell viability

    PubMed Central

    Cui, Xiaoxuan; Zhang, Lu; Magli, Amanda R.; Catera, Rosa; Yan, Xiao-Jie; Griffin, Daniel O.; Rothstein, Thomas L.; Barrientos, Jacqueline; Kolitz, Jonathan E.; Allen, Steven L.; Rai, Kanti R.; Chiorazzi, Nicholas; Chu, Charles C.

    2015-01-01

    The degree of chronic lymphocytic leukemia (CLL) B-cell antigen receptor (BCR) binding to myosin exposed apoptotic cells (MEACs) correlates with worse patient outcomes, suggesting a link to disease activity. Therefore, we studied MEAC formation and the effects of MEAC binding on CLL cells. In cell line studies, both intrinsic (spontaneous or camptothecin-induced) and extrinsic (FasL- or anti-Fas-induced) apoptosis created a high percent of MEACs over time in a process associated with caspase-3 activation, leading to cytoplasmic myosin cleavage and trafficking to cell membranes. The involvement of common apoptosis pathways suggests that most cells can produce MEACs and indeed CLL cells themselves form MEACs. Consistent with the idea that MEAC formation may be a signal to remove dying cells, we found that natural IgM antibodies bind to MEACs. Functionally, co-culture of MEACs with CLL cells, regardless of immunoglobulin heavy chain variable region gene mutation status, improved leukemic cell viability. Based on inhibitor studies, this improved viability involved BCR signaling molecules. These results support the hypothesis that stimulation of CLL cells with antigen, such as those on MEACs, promotes CLL cell viability, which in turn could lead to progression to worse disease. PMID:26220042

  18. Mechanism and challenges in commercialisation of algal biofuels.

    PubMed

    Singh, Anoop; Nigam, Poonam Singh; Murphy, Jerry D

    2011-01-01

    Biofuels made from algal biomass are being considered as the most suitable alternative energy in current global and economical scenario. Microalgae are known to produce and accumulate lipids within their cell mass which is similar to those found in many vegetable oils. The efficient lipid producer algae cell mass has been reported to contain more than 30% of their cell weight as lipids. According to US DOE microalgae have the potential to produce 100 times more oil per acre land than any terrestrial plants. This article reviews up to date literature on the composition of algae, mechanism of oil droplets, triacylglycerol (TAG) production in algal biomass, research and development made in the cultivation of algal biomass, harvesting strategies, and recovery of lipids from algal mass. The economical challenges in the production of biofuels from algal biomass have been discussed in view of the future prospects in the commercialisation of algal fuels.

  19. The proliferative effects of asbestos-exposed peripheral blood mononuclear cells on mesothelial cells

    PubMed Central

    MAKI, YUHO; NISHIMURA, YASUMITSU; TOYOOKA, SHINICHI; SOH, JUNICHI; TSUKUDA, KAZUNORI; SHIEN, KAZUHIKO; FURUKAWA, MASASHI; MURAOKA, TAKAYUKI; UENO, TSUYOSHI; TANAKA, NORIMITSU; YAMAMOTO, HIROMASA; ASANO, HIROAKI; MAEDA, MEGUMI; KUMAGAI-TAKEI, NAOKO; LEE, SUNI; MATSUZAKI, HIDENORI; OTSUKI, TAKEMI; MIYOSHI, SHINICHIRO

    2016-01-01

    Malignant mesothelioma (MM) is thought to arise from the direct effect of asbestos on mesothelial cells. However, MM takes a long time to develop following exposure to asbestos, which suggests that the effects of asbestos are complex. The present study examined the effects of asbestos exposure on the cell growth of MeT-5A human mesothelial cells via cytokines produced by immune cells. Peripheral blood mononuclear cells (PBMCs) were stimulated with antibodies against cluster of differentiation (CD)3 and CD28 upon exposure to the asbestos chrysotile A (CA) or crocidolite (CR); the growth of MeT-5A cells in media supplemented with PBMC culture supernatants was subsequently examined. MeT-5A cells exhibited an increase in proliferation when grown in supernatant from the 7-day PBMC culture exposed to CA or CR. Analysis of cytokine production demonstrated increased levels of granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-1α, IL-1β, IL-3, IL-5, IL-13 and IL-17A in supernatants. Individual administration of these cytokines, excluding G-CSF and GM-CSF, led to an increase in cell growth of MeT-5A, whereas this effect was not observed following the combined administration of these cytokines. The results indicate that cytokines secreted by immune cells upon exposure to asbestos cause an increase in the growth activity of mesothelial cells, suggesting that alterations in the production of cytokines by immune cells may contribute to tumorigenesis in individuals exposed to asbestos. PMID:27123108

  20. The influence of algal densities on the toxicity of chromium for Ceriodaphnia dubia Richard (Cladocera, Crustacea).

    PubMed

    Rodgher, S; Espíndola, E L G

    2008-05-01

    Food availability may affect metal toxicity for aquatic organisms. In the present study, the influence of high, medium and low densities of the algae Pseudokirchneriella subcapitata (10(6), 10(5) and 10(4) cells.mL(-1), respectively) on the chronic toxicity of chromium to the cladoceran Ceriodaphnia dubia was investigated. C. dubia was exposed to a range of chromium concentration from 2.71 to 34.04 microg.L(-1) and fed with algae at various densities. In another experiment, the green alga was exposed to chromium concentrations (94 to 774 microg.L(-1)) and supplied as food in different densities to zooplankton. The survival and reproduction of the cladoceran were measured in these toxicity tests. The IC50 for Cr to P. subcapitata and metal accumulated by algal cells were determined. The results of a bifactorial analysis (metal versus algal densities) showed that metal toxicity to zooplankton was dependent on algal densities. Significant toxic effects on the reproduction and survival of C. dubia were observed at 8.73, 18.22 and 34.04 microg.L(-1) Cr when the test organisms were fed with 10(6) cells.mL(-1) of P. subcapitata. Although the chlorophyta retain low chromium content, a decrease in the reproduction and survival of C. dubia occurred when they were fed with high algal density contaminated with 774 microg.L(-1) Cr. It was concluded that high algal density have an appreciable influence on chromium toxicity to daphnids.

  1. Recent Advances in Algal Genetic Tool Development

    SciTech Connect

    R. Dahlin, Lukas; T. Guarnieri, Michael

    2016-06-24

    The goal of achieving cost-effective biofuels and bioproducts derived from algal biomass will require improvements along the entire value chain, including identification of robust, high-productivity strains and development of advanced genetic tools. Though there have been modest advances in development of genetic systems for the model alga Chlamydomonas reinhardtii, progress in development of algal genetic tools, especially as applied to non-model algae, has generally lagged behind that of more commonly utilized laboratory and industrial microbes. This is in part due to the complex organellar structure of algae, including robust cell walls and intricate compartmentalization of target loci, as well as prevalent gene silencing mechanisms, which hinder facile utilization of conventional genetic engineering tools and methodologies. However, recent progress in global tool development has opened the door for implementation of strain-engineering strategies in industrially-relevant algal strains. Here, we review recent advances in algal genetic tool development and applications in eukaryotic microalgae.

  2. Mesodesma mactroides Gill Cells Exposed to Copper: Does Hyposmotic Saline Increase Cytotoxicity or Cellular Defenses?

    PubMed

    Anjos, V A; Galvão, J S; Santos, V R S; Souza, M M

    2016-11-01

    Gill cells of filter feeding mollusks have cellular defense mechanisms, such as multixenobiotic resistance (MXR), that allow them to extrude possible contaminants. To analyze the cytotoxicity and cellular defenses of gills in the clam Mesodesma mactroides, gill cells were exposed to copper in both iso- and hyposmotic solutions. Analysis of MXR activity by fluorescence microscopy showed that hyposmotic saline activated defenses, whereas the presence of copper in isosmotic solution inhibited the activation of defenses. Cell viability was decreased in cells exposed to copper in isosmotic saline, but not in cells exposed to hyposmotic saline. We conclude that when cells cannot defend themselves due to decreased MXR, cell death occurs. In addition, gill cells under hyposmotic conditions have a greater capacity for defense and a lower rate of cellular mortality than when they are maintained under isosmotic conditions.

  3. Detection of algal lipid accumulation due to nitrogen limitation via dielectric spectroscopy of Chlamydomonas reinhardtii suspensions in a coaxial transmission line sample cell.

    PubMed

    Bono, Michael S; Ahner, Beth A; Kirby, Brian J

    2013-09-01

    In this study, dielectric characterization of algae cell suspensions was used to detect lipid accumulation due to nitrogen starvation. Wild-type Chlamydomonas reinhardtii (CC-125) was cultivated in replete and nitrogen-limited conditions in order to achieve a range of lipid contents, as confirmed by Nile Red fluorescence measurements. A vector network analyzer was used to measure the dielectric scattering parameters of a coaxial region of concentrated cell suspension. The critical frequency fc of the normalized transmission coefficient |S21(*)| decreased with increasing lipid content but did not change with cell concentration. These observations were consistent with a decrease in cytoplasmic conductivity due to lipid accumulation in the preliminary transmission line model. This dielectric sensitivity to lipid content will facilitate the development of a rapid, noninvasive method for algal lipid measurement that could be implemented in industrial settings without the need for specialized staff and analytical facilities.

  4. Stochastic models for cells exposed to ionizing radiation

    SciTech Connect

    Yang, G.L.; Swenberg, C.E.

    1986-01-01

    The stochastic model for survivability of cells subjected to ionizing radiation initially formulated by Neyman and Puri is modified to include both the plating time to cell proliferation and dose saturation of potential lethal damage. This necessitates a reformulation of the cell survival and mutation probability. Based on the new model the authors derive the the probability of occurrence for several experimental end points. The predictions of the model compare favorably to data for diploid yeast cells irradiated with 30-MeV electrons.

  5. Changes in morphology, cell wall composition and soluble proteome in Rhodobacter sphaeroides cells exposed to chromate.

    PubMed

    Italiano, Francesca; Rinalducci, Sara; Agostiano, Angela; Zolla, Lello; De Leo, Francesca; Ceci, Luigi R; Trotta, Massimo

    2012-10-01

    The response of the carotenoidless Rhodobacter sphaeroides mutant R26 to chromate stress under photosynthetic conditions is investigated by biochemical and spectroscopic measurements, proteomic analysis and cell imaging. Cell cultures were found able to reduce chromate within 3-4 days. Chromate induces marked changes in the cellular dimension and morphology, as revealed by atomic force microscopy, along with compositional changes in the cell wall revealed by infrared spectroscopy. These effects are accompanied by significant changes in the level of several proteins: 15 proteins were found up-regulated and 15 down-regulated. The protein content found in chromate exposed cells is in good agreement with the biochemical, spectroscopic and microscopic results. Moreover at the present stage no specific chromate-reductase could be found in the soluble proteome, indicating that detoxification of the pollutant proceeds via aspecific reductants.

  6. In vitro action of sho-seiryu-to on allergen-exposed mononuclear cells.

    PubMed

    Tanaka, M; Inoue, K; Kitamura, Y; Shimada, A; Takano, H

    2014-01-01

    Although Sho-seiryu-to (SST), used as a traditional herbal (Kampo) medicine mainly in China and Korea, is shown to have immunomodulating potential, such as an anti-allergic one, its underlying mechanism has not been completely clarified. To partially address the issue, we explored its effects on allergen-exposed mononuclear cells. Male balb/c mice were intraperitoneally administered ovalbumin (OVA: 20 μg) plus alum or vehicle twice (Day 0 and Day 14). At Day 21, mice were sacrificed and splenocytes (mononuclear cells) were isolated and cultured in the presence or absence of OVA with or without SST. Thereafter, helper T-related cytokines in the culture supernatants were evaluated by means of ELISA. Protein level of interferon-γ was lower than 5.0 pg/mL in the supernatants from OVA– non-exposed or -exposed mononuclear cells in the presence or absence of OVA stimulation. On the other hand, SST induced the cytokine from both types of mononuclear cells in the presence (P < 0.05) or absence of OVA stimulation as compared to corresponding control. By contrast, interleukin (IL)-4 level tended to be decreased by SST in OVA-non-exposed mononuclear cells as did IL-13 in both non-exposed and exposed mononuclear cells as compared to vehicle. In conclusion, immunoregulating efficacy by SST on allergy-prone subjects may include, at least in part, restoring helper T balance mainly through hyperproduction of IFN-γ against mononuclear cells such as lymphocytes.

  7. Harmful Algal Blooms

    USGS Publications Warehouse

    Graham, Jennifer L.

    2007-01-01

    What are Harmful Algal Blooms (HABs)? Freshwater and marine harmful algal blooms (HABs) can occur anytime water use is impaired due to excessive accumulations of algae. HAB occurrence is affected by a complex set of physical, chemical, biological, hydrological, and meteorological conditions making it difficult to isolate specific causative environmental factors. Potential impairments include reduction in water quality, accumulation of malodorous scums in beach areas, algal production of toxins potent enough to poison both aquatic and terrestrial organisms, and algal production of taste-and-odor compounds that cause unpalatable drinking water and fish. HABs are a global problem, and toxic freshwater and (or) marine algae have been implicated in human and animal illness and death in over 45 countries worldwide and in at least 27 U.S. States (Yoo and others, 1995; Chorus and Bartram, 1999; Huisman and others, 2005).

  8. Indicators: Algal Toxins (microcystin)

    EPA Pesticide Factsheets

    Algal toxins are toxic substances released by some types of algae (phytoplankton) when they are present in large quantities (blooms) and decay or degrade. High nutrient levels and warm temperatures often result in favorable conditions for algae blooms.

  9. Viscoelastic properties of vascular endothelial cells exposed to uniaxial stretch

    NASA Astrophysics Data System (ADS)

    Osterday, Kathryn; Chew, Thomas; Loury, Phillip; Haga, Jason; Del Alamo, Juan C.; Chien, Shu

    2011-11-01

    Vascular endothelial cells (VECs) line the interior of blood vessels and regulate a variety of functions in the cardiovascular system. It is widely accepted that VECs will remodel themselves in response to mechanical stimuli, but few studies have analyzed the mechanical properties of these cells under stretch. We hypothesize that uniaxial stretch will cause an anisotropic realignment of actin filaments, and a change in the viscoelastic properties of the cell. To test this hypothesis, VECs were grown on a thin, transparent membrane mounted on a microscope. The membrane was stretched, consequently stretching the cells. Time-lapse sequences of the cells were taken every hour with a time resolution of 10 Hz. The random trajectories of intracellular endogenous particles were tracked using in-house algorithms. These trajectories were analyzed using a novel particle tracking microrheology formulation that takes into account the anisotropy of the cytoplasm of VECs. Supported by NSF CBET-1055697 CAREER Award (JCA) and NIH grants BRP HL064382 (SC), 1R01 HL080518 (SC).

  10. Ultrastructural changes in tracheal epithelial cells exposed to oxygen

    NASA Technical Reports Server (NTRS)

    Philpott, D. E.; Harrison, G. A.; Turnbill, C.; Black, S.

    1977-01-01

    White albino rats were sacrificed after 24, 36, 48, 72, and 96 h of exposure to 100% O2 at 1 atm. Tissue was prepared for the scanning electron microscope (SEM) by Critical Point Drying and for the transmission electron microscope (TEM) by plastic embedding. Scanning microscopy showed a loss of microvilli after 48 h of exposure. Cilia appeared relatively normal with SEM, but TEM revealed changes in the outer membrane. In TEM, nonciliated cells appeared swollen and often encroached on the ciliated cells. A heavy mucous blanket remained even after processing. All the changes observed that are induced by oxygen exposure contribute to mucostasis, reducing and/or halting mucociliary clearance.

  11. Pretreatment of algae-laden and manganese-containing waters by oxidation-assisted coagulation: Effects of oxidation on algal cell viability and manganese precipitation.

    PubMed

    Lin, Jr-Lin; Hua, Lap-Cuong; Wu, Yuting; Huang, Chihpin

    2016-02-01

    Preoxidation is manipulated to improve performance of algae and soluble manganese (Mn) removal by coagulation-sedimentation for water treatment plants (WTPs) when large amount of soluble Mn presents in algae-laden waters. This study aimed to investigate the effects of preoxidation on the performance of coagulation-sedimentation for the simultaneous removal of algae and soluble Mn, including ionic and complexed Mn. NaOCl, ClO2, and KMnO4 were used to pretreat such algae-laden and Mn containing waters. The variation of algal cell viability, residual cell counts, and concentrations of Mn species prior to and after coagulation-sedimentation step were investigated. Results show that NaOCl dosing was effective in reducing the viability of algae, but precipitated little Mn. ClO2 dosing had a strongest ability to lower algae viability and oxidize ionic and complexed soluble Mn, where KMnO4 dosing oxidized ionic and complexed Mn instead of reducing the viability of cells. Preoxidation by NaOCl only improved the algae removal by sedimentation, whereas most of soluble Mn still remained. On the other hand, ClO2 preoxidation substantially improved the performance of coagulation-sedimentation for simultaneous removal of algae and soluble Mn. Furthermore, KMnO4 preoxidation did improve the removal of algae by sedimentation, but left significant residual Mn in the supernatant. Images from FlowCAM showed changes in aspect ratio (AR) and transparency of algae-Mn flocs during oxidation-assisted coagulation, and indicates that an effective oxidation can improve the removal of most compact algae-Mn flocs by sedimentation. It suggests that an effective preoxidation for reducing algal cell viability and the concentration of soluble Mn is a crucial step for upgrading the performance of coagulation-sedimentation.

  12. Correlation between dielectric property by dielectrophoretic levitation and growth activity of cells exposed to electric field.

    PubMed

    Hakoda, Masaru; Hirota, Yusuke

    2013-09-01

    The purpose of this study is to develop a system analyzing cell activity by the dielectrophoresis method. Our previous studies revealed a correlation between the growth activity and dielectric property (Re[K(ω)]) of mouse hybridoma 3-2H3 cells using dielectrophoretic levitation. Furthermore, it was clarified that the differentiation activity of many stem cells could be evaluated by the Re[K(ω)] without differentiation induction. In this paper, 3-2H3 cells exposed to an alternating current (AC) electric field or a direct current (DC) electric field were cultivated, and the influence of damage by the electric field on the growth activity of the cells was examined. To evaluate the activity of the cells by measuring the Re[K(ω)], the correlation between the growth activity and the Re[K(ω)] of the cells exposed to the electric field was examined. The relations between the cell viability, growth activity, and Re[K(ω)] in the cells exposed to the AC electric field were obtained. The growth activity of the cells exposed to the AC electric field could be evaluated by the Re[K(ω)]. Furthermore, it was found that the adverse effects of the electric field on the cell viability and the growth activity were smaller in the AC electric field than the DC electric field.

  13. Autosomal mutants of proton-exposed kidney cells display frequent loss of heterozygosity on nonselected chromosomes.

    PubMed

    Grygoryev, Dmytro; Dan, Cristian; Gauny, Stacey; Eckelmann, Bradley; Ohlrich, Anna P; Connolly, Marissa; Lasarev, Michael; Grossi, Gianfranco; Kronenberg, Amy; Turker, Mitchell S

    2014-05-01

    High-energy protons found in the space environment can induce mutations and cancer, which are inextricably linked. We hypothesized that some mutants isolated from proton-exposed kidneys arose through a genome-wide incident that causes loss of heterozygosity (LOH)-generating mutations on multiple chromosomes (termed here genomic LOH). To test this hypothesis, we examined 11 pairs of nonselected chromosomes for LOH events in mutant cells isolated from the kidneys of mice exposed to 4 or 5 Gy of 1 GeV protons. The mutant kidney cells were selected for loss of expression of the chromosome 8-encoded Aprt gene. Genomic LOH events were also assessed in Aprt mutants isolated from isogenic cultured kidney epithelial cells exposed to 5 Gy of protons in vitro. Control groups were spontaneous Aprt mutants and clones isolated without selection from the proton-exposed kidneys or cultures. The in vivo results showed significant increases in genomic LOH events in the Aprt mutants from proton-exposed kidneys when compared with spontaneous Aprt mutants and when compared with nonmutant (i.e., nonselected) clones from the proton-exposed kidneys. A bias for LOH events affecting chromosome 14 was observed in the proton-induced Aprt mutants, though LOH for this chromosome did not confer increased radiation resistance. Genomic LOH events were observed in Aprt mutants isolated from proton-exposed cultured kidney cells; however the incidence was fivefold lower than in Aprt mutants isolated from exposed intact kidneys, suggesting a more permissive environment in the intact organ and/or the evolution of kidney clones prior to their isolation from the tissue. We conclude that proton exposure creates a subset of viable cells with LOH events on multiple chromosomes, that these cells form and persist in vivo, and that they can be isolated from an intact tissue by selection for a mutation on a single chromosome.

  14. Algal recycling enhances algal productivity and settleability in Pediastrum boryanum pure cultures.

    PubMed

    Park, Jason B K; Craggs, Rupert J; Shilton, Andy N

    2015-12-15

    Recycling a portion of gravity harvested algae (i.e. algae and associated bacteria biomass) has been shown to improve both algal biomass productivity and harvest efficiency by maintaining the dominance of a rapidly-settleable colonial alga, Pediastrum boryanum in both pilot-scale wastewater treatment High Rate Algal Ponds (HRAP) and outdoor mesocosms. While algal recycling did not change the relative proportions of algae and bacteria in the HRAP culture, the contribution of the wastewater bacteria to the improved algal biomass productivity and settleability with the recycling was not certain and still required investigation. P. boryanum was therefore isolated from the HRAP and grown in pure culture on synthetic wastewater growth media under laboratory conditions. The influence of recycling on the productivity and settleability of the pure P. boryanum culture was then determined without wastewater bacteria present. Six 1 L P. boryanum cultures were grown over 30 days in a laboratory growth chamber simulating New Zealand summer conditions either with (Pr) or without (Pc) recycling of 10% of gravity harvested algae. The cultures with recycling (Pr) had higher algal productivity than the controls (Pc) when the cultures were operated at both 4 and 3 d hydraulic retention times by 11% and 38% respectively. Furthermore, algal recycling also improved 1 h settleability from ∼60% to ∼85% by increasing the average P. boryanum colony size due to the extended mean cell residence time and promoted formation of large algal bio-flocs (>500 μm diameter). These results demonstrate that the presence of wastewater bacteria was not necessary to improve algal productivity and settleability with algal recycling.

  15. Arginase inhibition enhances angiogenesis in endothelial cells exposed to hypoxia.

    PubMed

    Wang, Lin; Bhatta, Anil; Toque, Haroldo A; Rojas, Modesto; Yao, Lin; Xu, Zhimin; Patel, Chintan; Caldwell, Ruth B; Caldwell, R William

    2015-03-01

    Hypoxia-induced arginase elevation plays an essential role in several vascular diseases but influence of arginase on hypoxia-mediated angiogenesis is completely unknown. In this study, in vitro network formation in bovine aortic endothelial cells (BAEC) was examined after exposure to hypoxia for 24h with or without arginase inhibition. Arginase activity, protein levels of the two arginase isoforms, eNOS, and VEGF as well as production of NO and ROS were examined to determine the involvement of arginase in hypoxia-mediated angiogenesis. Hypoxia elevated arginase activity and arginase 2 expression but reduced active p-eNOS(Ser1177) and NO levels in BAEC. In addition, both VEGF protein levels and endothelial elongation and network formation were reduced with continued hypoxia, whereas ROS levels increased and NO levels decreased. Arginase inhibition limited ROS, restored NO formation and VEGF expression, and prevented the reduction of angiogenesis. These results suggest a fundamental role of arginase activity in regulating angiogenic function.

  16. DNA Fragmentation in mammalian cells exposed to various light ions

    NASA Astrophysics Data System (ADS)

    Belli, M.; Cherubini, R.; Dalla Vecchia, M.; Dini, V.; Esposito, G.; Moschini, G.; Sapora, O.; Signoretti, C.; Simone, G.; Sorrentino, E.; Tabocchini, M. A.

    Elucidation of how effects of densely ionizing radiation at cellular level are linked to DNA damage is fundamental for a better understanding of the mechanisms leading to genomic damage (especially chromosome aberrations) and developing biophysical models to predict space radiation effects. We have investigated the DNA fragmentation patterns induced in Chinese hamster V79 cells by 31 keV/μm protons, 123 keV/μm helium-4 ions and γ-rays in the size range 0.023-5.7 Mbp, using calibrated Pulsed Field Gel Electrophoresis (PFGE). The frequency distributions of fragments induced by the charged particles were shifted towards smaller sizes with respct to that induced by comparable doses of γ-rays. The DSB yields, evaluated from the fragments induced in the size range studied, were higher for protons and helium ions than for γ-rays by a factor of about 1.9 and 1.2, respectively. However, these ratios do not adequately reflect the RBE observed on the same cells for inactivation and mutation induced by these beams. This is a further indication for the lack of correlation between the effects exerted at cellular level and the initial yield of DSB. The dependence on radiation quality of the fragmentation pattern suggests that it may have a role in damage reparability. We have analyzed these patterns with a "random breakage" model generalized in order to consider the initial non-random distribution of the DNA molecules. Our results suggest that a random breakage mechanism can describe with a reasonable approximation the DNA fragmentation induced by γ-rays, while the approximation is not so good for light ions, likely due to the interplay between ion tracks and chromatin organization at the loop level.

  17. Algal swimming velocities signal fatty acid accumulation.

    PubMed

    Hansen, Travis J; Hondzo, Miki; Mashek, Mara T; Mashek, Douglas G; Lefebvre, Paul A

    2013-01-01

    The use of microalgae for biofuel production will be beneficial to society if we can produce biofuels at large scales with minimal mechanical energy input in the production process. Understanding micro-algal physiological responses under variable environmental conditions in bioreactors is essential for the optimization of biofuel production. We demonstrate that measuring micro-algal swimming speed provides information on culture health and total fatty acid accumulation. Three strains of Chlamydomonas reinhardtii were grown heterotrophically on acetate and subjected to various levels of nitrogen starvation. Other nutrient levels were explored to determine their effect on micro-algal kinetics. Swimming velocities were measured with two-dimensional micro-particle tracking velocimetry. The results show an inverse linear relationship between normalized total fatty acid mass versus swimming speed of micro-algal cells. Analysis of RNA sequencing data confirms these results by demonstrating that the biological processes of cell motion and the generation of energy precursors are significantly down-regulated. Experiments demonstrate that changes in nutrient concentration in the surrounding media also affect swimming speed. The findings have the potential for the in situ and indirect assessment of lipid content by measuring micro-algal swimming kinetics.

  18. DETAIL OF ZINC CLEANER CELL INTERIOR (EXPOSED AT F/45 FOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL OF ZINC CLEANER CELL INTERIOR (EXPOSED AT F/45 FOR DEPTH OF FIELD PURPOSES). NOTE GALIGHER STYLE BAFFLES AND TENDENCY OF ZINC TO BUILD UP ON CELL COMPONENTS. - Shenandoah-Dives Mill, 135 County Road 2, Silverton, San Juan County, CO

  19. Method and system of culturing an algal mat

    DOEpatents

    Das, Keshav C; Cannon, Benjamin R; Bhatnagar, Ashish; Chinnasamy, Senthil

    2014-05-13

    A system and method for culturing algae are presented. The system and method utilize a fog of growth medium that is delivered to an algal mat generator along with a stream of CO.sub.2 to promote growth of algal cells contained in the generator.

  20. Leukemia-related chromosomal loss detected in hematopoietic progenitor cells of benzene-exposed workers

    PubMed Central

    Zhang, Luoping; Lan, Qing; Ji, Zhiying; Li, Guilan; Shen, Min; Vermeulen, Roel; Guo, Weihong; Hubbard, Alan E.; McHale, Cliona M.; Rappaport, Stephen M.; Hayes, Richard B.; Linet, Martha S.; Yin, Songnian; Smith, Martyn T.; Rothman, Nathaniel

    2012-01-01

    Benzene exposure causes acute myeloid leukemia, and hematotoxicity, shown as suppression of mature blood and myeloid progenitor cell numbers. As the leukemia-related aneuploidies monosomy 7 and trisomy 8 previously had been detected in the mature peripheral blood cells of exposed workers, we hypothesized that benzene could cause leukemia through the induction of these aneuploidies in hematopoietic stem and progenitor cells. We measured loss and gain of chromosomes 7 and 8 by fluorescence in situ hybridization in interphase colony-forming unit-granulocyte-macrophage (CFU-GM) cells cultured from otherwise healthy benzene-exposed (n=28) and unexposed (n=14) workers. CFU-GM monosomy 7 and 8 levels (but not trisomy) were significantly increased in subjects exposed to benzene overall, compared to levels in the control subjects (p=0.0055 and p=0.0034, respectively). Levels of monosomy 7 and 8 were significantly increased in subjects exposed to <10 ppm (20%, p=0.0419 and 28%, p=0.0056, respectively) and ≥10 ppm (48%, p=0.0045 and 32%, p=0.0354) benzene, compared with controls, and significant exposure-response trends were detected (ptrend=0.0033 and 0.0057). These data show that monosomies 7 and 8 are produced in a dose-dependent fashion in the blood progenitor cells of workers exposed to benzene and may be mechanistically relevant biomarkers of early effect for benzene and other leukemogens. PMID:22643707

  1. Dissolved organic matter reduces algal accumulation of methylmercury

    USGS Publications Warehouse

    Luengen, Allison C.; Fisher, Nicholas S.; Bergamaschi, Brian A.

    2012-01-01

    Dissolved organic matter (DOM) significantly decreased accumulation of methylmercury (MeHg) by the diatom Cyclotella meneghiniana in laboratory experiments. Live diatom cells accumulated two to four times more MeHg than dead cells, indicating that accumulation may be partially an energy-requiring process. Methylmercury enrichment in diatoms relative to ambient water was measured by a volume concentration factor (VCF). Without added DOM, the maximum VCF was 32 x 104, and the average VCF (from 10 to 72 h) over all experiments was 12.6 x 104. At very low (1.5 mg/L) added DOM, VCFs dropped by approximately half. At very high (20 mg/L) added DOM, VCFs dropped 10-fold. Presumably, MeHg was bound to a variety of reduced sulfur sites on the DOM, making it unavailable for uptake. Diatoms accumulated significantly more MeHg when exposed to transphilic DOM extracts than hydrophobic ones. However, algal lysate, a labile type of DOM created by resuspending a marine diatom in freshwater, behaved similarly to a refractory DOM isolate from San Francisco Bay. Addition of 67 μM L-cysteine resulted in the largest drop in VCFs, to 0.28 x 104. Although the DOM composition influenced the availability of MeHg to some extent, total DOM concentration was the most important factor in determining algal bioaccumulation of MeHg.

  2. High frequency of malaria-specific T cells in non-exposed humans.

    PubMed

    Zevering, Y; Amante, F; Smillie, A; Currier, J; Smith, G; Houghten, R A; Good, M F

    1992-03-01

    A major goal of current candidate malaria vaccines is to stimulate the expansion of clones of malaria-specific lymphocytes. We have examined the in vitro T cell responses of a group of malaria exposed and non-exposed adult Caucasian donors to recombinant circumsporozoite (CS) proteins, one of which is undergoing clinical trials, to blood-stage parasites, and to synthetic peptides copying the CS protein and defined blood-stage proteins. In nearly all individuals tested, CD4 T cell proliferation or lymphokine production occurred in response to whole parasite or CS protein stimulation, and T cells from many individuals responded to synthetic peptides. T cell responses were major histocompatibility complex-restricted, and stimulation of T cells with malaria parasites or CS protein did not appear to expand a population of T cell receptor gamma/delta cells. Malaria-specific responses were independent of prior malaria exposure, and in some cases exceeded the magnitude of response to tetanus toxoid. Specific T cells are present in high frequency in the peripheral blood of many donors who have never been exposed to malaria. Although malaria-specific CD4 T cells play an important role in immunity, these data question whether vaccines need to stimulate such cells, and focus attention on other aspects of malaria immunity which may be more critical to a successful vaccine.

  3. Dynamic metabolic exchange governs a marine algal-bacterial interaction

    PubMed Central

    Segev, Einat; Wyche, Thomas P; Kim, Ki Hyun; Petersen, Jörn; Ellebrandt, Claire; Vlamakis, Hera; Barteneva, Natasha; Paulson, Joseph N; Chai, Liraz; Clardy, Jon; Kolter, Roberto

    2016-01-01

    Emiliania huxleyi is a model coccolithophore micro-alga that generates vast blooms in the ocean. Bacteria are not considered among the major factors influencing coccolithophore physiology. Here we show through a laboratory model system that the bacterium Phaeobacter inhibens, a well-studied member of the Roseobacter group, intimately interacts with E. huxleyi. While attached to the algal cell, bacteria initially promote algal growth but ultimately kill their algal host. Both algal growth enhancement and algal death are driven by the bacterially-produced phytohormone indole-3-acetic acid. Bacterial production of indole-3-acetic acid and attachment to algae are significantly increased by tryptophan, which is exuded from the algal cell. Algal death triggered by bacteria involves activation of pathways unique to oxidative stress response and programmed cell death. Our observations suggest that bacteria greatly influence the physiology and metabolism of E. huxleyi. Coccolithophore-bacteria interactions should be further studied in the environment to determine whether they impact micro-algal population dynamics on a global scale. DOI: http://dx.doi.org/10.7554/eLife.17473.001 PMID:27855786

  4. Millimeter wave induced reversible externalization of phosphatidylserine molecules in cells exposed in vitro.

    PubMed

    Szabo, Imre; Kappelmayer, Janos; Alekseev, Stanislav I; Ziskin, Marvin C

    2006-04-01

    In vitro exposure of refrigerated samples (4 degrees C) of anti-coagulated blood with millimeter waves (MMWs) at incident power densities (IPDs) between 0.55 and 1.23 W/cm2 has been found to induce clot formation. We found a small but statistically significant change in clot size with increasing IPD value. MMW exposure of blood samples starting at room temperature (22 degrees C) did not induce blood coagulation; neither did conventional heating at temperatures up to 40 degrees C. Since cell-free plasma did not clot upon MMW exposure, the role of blood cells was particularly analyzed. Experiments on various mixtures of blood cells with plasma revealed an important role of red blood cells (RBC) in the coagulation process. Plasma coagulation also developed within the MMW beam above dense keratinocyte (HaCaT) monolayers suggesting it lacked cell-type specificity. We hypothesized that alteration of the membrane surface in exposed cells might be responsible for the circumscribed coagulation. The thrombogenic role of externalized phosphatidylserine (PS) molecules is well known. Therefore, we carried out experiments for immunolabeling PS molecules with fluorescein isothiocyanate (FITC)-conjugated Annexin V on exposed cells. Fluorescence microscopy of the adherent human keratinocytes (HaCaT) and murine melanoma cells (B16F10) showed that MMW exposure at an IPD of 1.23 W/cm2 is capable of inducing reversible externalization of PS molecules in cells within the beam area without detectable membrane damage. Nonadherent Jurkat cells exposed to MMW at an IPD of 34.5 mW/cm2 also showed reversible PS externalization with flow cytometry, whether the cell temperature was held constant or permitted to rise. These results suggest that certain biological effects induced by MMWs could be initiated by membrane changes in exposed cells.

  5. Increased frequency of micronucleated exfoliated cells among humans exposed in vivo to mobile telephone radiations.

    PubMed

    Yadav, Abhay Singh; Sharma, Manoj Kumar

    2008-02-29

    The health concerns have been raised following the enormous increase in the use of wireless mobile telephones throughout the world. This investigation had been taken, with the motive to find out whether mobile phone radiations cause any in vivo effects on the frequency of micronucleated exfoliated cells in the exposed subjects. A total of 109 subjects including 85 regular mobile phone users (exposed) and 24 non-users (controls) had participated in this study. Exfoliated cells were obtained by swabbing the buccal-mucosa from exposed as well as sex-age-matched controls. One thousand exfoliated cells were screened from each individual for nuclear anomalies including micronuclei (MN), karyolysis (KL), karyorrhexis (KH), broken egg (BE) and binucleated (BN) cells. The average daily duration of exposure to mobile phone radiations is 61.26 min with an overall average duration of exposure in term of years is 2.35 years in exposed subjects along with the 9.84+/-0.745 micronucleated cells (MNCs) and 10.72+/-0.889 total micronuclei (TMN) as compared to zero duration of exposure along with average 3.75+/-0.774 MNC and 4.00+/-0.808 TMN in controls. The means are significantly different in case of MNC and TMN at 0.01% level of significance. The mean of KL in controls is 13.17+/-2.750 and in exposed subjects is 13.06+/-1.793. The value of means of KH in exposed subjects (1.84+/-0.432) is slightly higher than in controls (1.42+/-0.737). Mean frequency of broken egg is found to be more in exposed subjects (0.65+/-0.276) as compared to controls (0.50+/-0.217). Frequency of presence of more than one nucleus in a cell (binucleated) is also higher in exposed (2.72+/-0.374) in comparison to controls (0.67+/-0.231). Although there is a slight increase in mean frequency of KH, BE and BN in exposed subjects but the difference is not found statistically significant. Correlation between 0-1, 1-2, 2-3 and 3-4 years of exposure and the frequency of MNC and TMN has been calculated and found to

  6. Algal Biofuels Fact Sheet

    SciTech Connect

    2009-10-27

    This fact sheet provides information on algal biofuels, which are generating considerable interest around the world. They may represent a sustainable pathway for helping to meet the U.S. biofuel production targets set by the Energy Independence and Security Act of 2007.

  7. Harmful Algal Blooms Research

    EPA Science Inventory

    This project represents the Agency’s first effort to unify harmful algal blooms (HABs) research that had been previously carried out in isolation within various laboratories. A unified program is the most efficient way generate useful results for the Agency’s decision...

  8. Cell cycle synchronization reveals greater G2/M-phase accumulation of lung epithelial cells exposed to titanium dioxide nanoparticles.

    PubMed

    Medina-Reyes, Estefany I; Bucio-López, Laura; Freyre-Fonseca, Verónica; Sánchez-Pérez, Yesennia; García-Cuéllar, Claudia M; Morales-Bárcenas, Rocío; Pedraza-Chaverri, José; Chirino, Yolanda I

    2015-03-01

    Titanium dioxide has been classified in the 2B group as a possible human carcinogen by the International Agency for Research on Cancer, and amid concerns of its exposure, cell cycle alterations are an important one. However, several studies show inconclusive effects, mainly because it is difficult to compare cell cycle effects caused by TiO2 nanoparticle (NP) exposure between different shapes and sizes of NP, cell culture types, and time of exposure. In addition, cell cycle is frequently analyzed without cell cycle synchronization, which may also mask some effects. We hypothesized that synchronization after TiO2 NP exposure could reveal dissimilar cell cycle progression when compared with unsynchronized cell population. To test our hypothesis, we exposed lung epithelial cells to 1 and 10 μg/cm(2) TiO2 NPs for 7 days and one population was synchronized by serum starvation and inhibition of ribonucleotide reductase using hydroxyurea. Another cell population was exposed to TiO2 NPs under the same experimental conditions, but after treatments, cell cycle was analyzed without synchronization. Our results showed that TiO2 NP-exposed cells without synchronization had no changes in cell cycle distribution; however, cell population synchronized after 1 and 10 μg/cm(2) TiO2 NP treatment showed a 1.5-fold and 1.66-fold increase, respectively, in proliferation. Synchronized cells also reveal a faster capability of TiO2 NP-exposed cells to increase cell population in the G2/M phase in the following 9 h after synchronization. We conclude that synchronization discloses a greater percentage of cells in the G2/M phase and higher proliferation than TiO2 NP-synchronized cells.

  9. Cell-free expression of the APP transmembrane fragments with Alzheimer's disease mutations using algal amino acid mixture for structural NMR studies.

    PubMed

    Bocharova, Olga V; Urban, Anatoly S; Nadezhdin, Kirill D; Bocharov, Eduard V; Arseniev, Alexander S

    2016-07-01

    Structural investigations need ready supply of the isotope labeled proteins with inserted mutations n the quantities sufficient for the heteronuclear NMR. Though cell-free expression system has been widely used in the past years, high startup cost and complex compound composition prevent many researches from the developing this technique, especially for membrane protein production. Here we demonstrate the utility of a robust, cost-optimized cell-free expression technique for production of the physiologically important transmembrane fragment of amyloid precursor protein, APP686-726, containing Alzheimer's disease mutations in the juxtamembrane (E693G, Arctic form) and the transmembrane parts (V717G, London form, or L723P, Australian form). The protein cost was optimized by varying the FM/RM ratio as well as the amino acid concentration. We obtained the wild-type and mutant transmembrane fragments in the pellet mode of continuous exchange cell-free system consuming only commercial algal mixture of the (13)C,(15)N-labeled amino acids. Scaling up analytical tests, we achieved milligram quantity yields of isotope labeled wild-type and mutant APP686-726 for structural studies by high resolution NMR spectroscopy in membrane mimicking environment. The described approach has from 5 to 23-fold cost advantage over the bacterial expression methods described earlier and 1.5 times exceeds our previous result obtained with the longer APP671-726WT fragment.

  10. BCG vaccination induces HIV target cell activation in HIV-exposed infants in a randomized trial

    PubMed Central

    Gasper, Melanie A.; Hesseling, Anneke C.; Mohar, Isaac; Myer, Landon; Azenkot, Tali; Passmore, Jo-Ann S.; Hanekom, Willem; Cotton, Mark F.; Crispe, I. Nicholas; Sodora, Donald L.; Jaspan, Heather B.

    2017-01-01

    BACKGROUND. Bacillus Calmette-Guérin (BCG) vaccine is administered at birth to protect infants against tuberculosis throughout Africa, where most perinatal HIV-1 transmission occurs. We examined whether BCG vaccination alters the levels of activated HIV target T cells in HIV-exposed South African infants. METHODS. HIV-exposed infants were randomized to receive routine (at birth) or delayed (at 8 weeks) BCG vaccination. Activated and CCR5-expressing peripheral blood CD4+ T cell, monocyte, and NK cell frequencies were evaluated by flow cytometry and immune gene expression via PCR using Biomark (Fluidigm). RESULTS. Of 149 infants randomized, 92% (n = 137) were retained at 6 weeks: 71 in the routine BCG arm and 66 in the delayed arm. Routine BCG vaccination led to a 3-fold increase in systemic activation of HIV target CD4+CCR5+ T cells (HLA-DR+CD38+) at 6 weeks (0.25% at birth versus 0.08% in delayed vaccination groups; P = 0.029), which persisted until 8 weeks of age when the delayed arm was vaccinated. Vaccination of the infants in the delayed arm at 8 weeks resulted in a similar increase in activated CD4+CCR5+ T cells. The increase in activated T cells was associated with increased levels of MHC class II transactivator (CIITA), IL12RB1, and IFN-α1 transcripts within peripheral blood mononuclear cells but minimal changes in innate cells. CONCLUSION. BCG vaccination induces immune changes in HIV-exposed infants, including an increase in the proportion of activated CCR5+CD4+ HIV target cells. These findings provide insight into optimal BCG vaccine timing to minimize the risks of HIV transmissions to exposed infants while preserving potential benefits conferred by BCG vaccination. TRIAL REGISTRATION. ClinicalTrials.gov NCT02062580. FUNDING. This trial was sponsored by the Elizabeth Glaser Pediatric AIDS Foundation (MV-00-9-900-01871-0-00) and the Thrasher Foundation (NR-0095); for details, see Acknowledgments.

  11. Determining adaptive and adverse oxidative stress responses in human bronical epithelial cells exposed to zinc

    EPA Science Inventory

    Determining adaptive and adverse oxidative stress responses in human bronchial epithelial cells exposed to zincJenna M. Currier1,2, Wan-Yun Cheng1, Rory Conolly1, Brian N. Chorley1Zinc is a ubiquitous contaminant of ambient air that presents an oxidant challenge to the human lung...

  12. Antioxidant enzyme activities of human peripheral blood mononuclear cells exposed to trace elements.

    PubMed

    Kuppusamy, U R; Dharmani, M; Kanthimathi, M S; Indran, M

    2005-07-01

    The trace elements copper, zinc, and selenium are important immune modulators and essential cofactors of the antioxidant enzymes. In the present study, the proliferative effect of human peripheral mononuclear cells (PBMCs) that have been exposed to copper, zinc, and selenium and the corresponding activities of antioxidant enzymes, namely superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase, were determined. Zinc and copper stimulated the PBMC proliferation in a dose-dependent manner within the dose range 25-200 micromol/L. SOD and GPx activities in PBMCs exposed to zinc were inhibited, whereas catalase activity was unaffected. All the three antioxidant enzymes in the cells exposed to copper were inhibited. Selenium exerted more potent inhibition of the cell proliferation while causing stimulation of the antioxidant enzymes at the lowest dose (25 micromol/L) than at the highest dose (200 micromol/L) tested. A significant negative correlation was observed between proliferation and antioxidant enzyme (SOD and GPx) activities in trace-element-exposed PBMC. The present findings substantiate the importance of trace elements as immune modulators and the involvement of enzymatic antioxidant system in the immune cell regulation.

  13. SIGNALING MECHANISMS IN HUMAN AIRWAY EPITHELIAL CELLS EXPOSED TO CARBON ULTRAFINE PARTICLES

    EPA Science Inventory

    SIGNALING MECHANISMS IN HUMAN AIRWAY EPITHELIAL CELLS EXPOSED TO CARBON ULTRAFINE PARTICLES
    Y.M. Kim, A.G. Lenz, R. Silbajoris, I. Jaspers and J.M. Samet. Department of Environmental Sciences and Engineering and Center for Environmental Medicine, University of North Carolina, ...

  14. Accelerating Commercialization of Algal Biofuels Through Partnerships (Brochure)

    SciTech Connect

    Not Available

    2011-10-01

    This brochure describes National Renewable Energy Laboratory's (NREL's) algal biofuels research capabilities and partnership opportunities. NREL is accelerating algal biofuels commercialization through: (1) Advances in applied biology; (2) Algal strain development; (3) Development of fuel conversion pathways; (4) Techno-economic analysis; and (5) Development of high-throughput lipid analysis methodologies. NREL scientists and engineers are addressing challenges across the algal biofuels value chain, including algal biology, cultivation, harvesting and extraction, and fuel conversion. Through partnerships, NREL can share knowledge and capabilities in the following areas: (1) Algal Biology - A fundamental understanding of algal biology is key to developing cost-effective algal biofuels processes. NREL scientists are experts in the isolation and characterization of microalgal species. They are identifying genes and pathways involved in biofuel production. In addition, they have developed a high-throughput, non-destructive technique for assessing lipid production in microalgae. (2) Cultivation - NREL researchers study algal growth capabilities and perform compositional analysis of algal biomass. Laboratory-scale photobioreactors and 1-m2 open raceway ponds in an on-site greenhouse allow for year-round cultivation of algae under a variety of conditions. A bioenergy-focused algal strain collection is being established at NREL, and our laboratory houses a cryopreservation system for long-term maintenance of algal cultures and preservation of intellectual property. (3) Harvesting and Extraction - NREL is investigating cost-effective harvesting and extraction methods suitable for a variety of species and conditions. Areas of expertise include cell wall analysis and deconstruction and identification and utilization of co-products. (4) Fuel Conversion - NREL's excellent capabilities and facilities for biochemical and thermochemical conversion of biomass to biofuels are being

  15. Algal functional annotation tool

    SciTech Connect

    2012-07-12

    Abstract BACKGROUND: Progress in genome sequencing is proceeding at an exponential pace, and several new algal genomes are becoming available every year. One of the challenges facing the community is the association of protein sequences encoded in the genomes with biological function. While most genome assembly projects generate annotations for predicted protein sequences, they are usually limited and integrate functional terms from a limited number of databases. Another challenge is the use of annotations to interpret large lists of 'interesting' genes generated by genome-scale datasets. Previously, these gene lists had to be analyzed across several independent biological databases, often on a gene-by-gene basis. In contrast, several annotation databases, such as DAVID, integrate data from multiple functional databases and reveal underlying biological themes of large gene lists. While several such databases have been constructed for animals, none is currently available for the study of algae. Due to renewed interest in algae as potential sources of biofuels and the emergence of multiple algal genome sequences, a significant need has arisen for such a database to process the growing compendiums of algal genomic data. DESCRIPTION: The Algal Functional Annotation Tool is a web-based comprehensive analysis suite integrating annotation data from several pathway, ontology, and protein family databases. The current version provides annotation for the model alga Chlamydomonas reinhardtii, and in the future will include additional genomes. The site allows users to interpret large gene lists by identifying associated functional terms, and their enrichment. Additionally, expression data for several experimental conditions were compiled and analyzed to provide an expression-based enrichment search. A tool to search for functionally-related genes based on gene expression across these conditions is also provided. Other features include dynamic visualization of genes on KEGG

  16. Regulation of the pigment optical density of an algal cell: filling the gap between photosynthetic productivity in the laboratory and in mass culture.

    PubMed

    Formighieri, Cinzia; Franck, Fabrice; Bassi, Roberto

    2012-11-30

    An increasing number of investors is looking at algae as a viable source of biofuels, beside cultivation for human/animal feeding or to extract high-value chemicals and pharmaceuticals. However, present biomass productivities are far below theoretical estimations implying that a large part of the available photosynthetically active radiation is not used in photosynthesis. Light utilisation inefficiency and rapid light attenuation within a mass culture due to high pigment optical density of wild type strains have been proposed as major limiting factors reducing solar-to-biomass conversion efficiency. Analysis of growth yields of mutants with reduced light-harvesting antennae and/or reduced overall pigment concentration per cell, generated by either mutagenesis or genetic engineering, could help understanding limiting factors for biomass accumulation in photobioreactor. Meanwhile, studies on photo-acclimation can provide additional information on the average status of algal cells in a photobioreactor to be used in modelling-based predictions. Identifying limiting factors in solar-to-biomass conversion efficiency is the first step for planning strategies of genetic improvement and domestication of algae to finally fill the gap between theoretical and industrial photosynthetic productivity.

  17. {sub p}53-Dependent Adaptive Responses in Human Cells Exposed to Space Radiations

    SciTech Connect

    Takahashi, Akihisa; Su Xiaoming; Suzuki, Hiromi; Omori, Katsunori; Seki, Masaya; Hashizume, Toko; Shimazu, Toru; Ishioka, Noriaki; Iwasaki, Toshiyasu; Ohnishi, Takeo

    2010-11-15

    Purpose: It has been reported that priming irradiation or conditioning irradiation with a low dose of X-rays in the range of 0.02-0.1 Gy induces a p53-dependent adaptive response in mammalian cells. The aim of the present study was to clarify the effect of space radiations on the adaptive response. Methods and Materials: Two human lymphoblastoid cell lines were used; one cell line bears a wild-type p53 (wtp53) gene, and another cell line bears a mutated p53 (mp53) gene. The cells were frozen during transportation on the space shuttle and while in orbit in the International Space Station freezer for 133 days between November 15, 2008 and March 29, 2009. After the frozen samples were returned to Earth, the cells were cultured for 6 h and then exposed to a challenging X-ray-irradiation (2 Gy). Cellular sensitivity, apoptosis, and chromosome aberrations were scored using dye-exclusion assays, Hoechst33342 staining assays, and chromosomal banding techniques, respectively. Results: In cells exposed to space radiations, adaptive responses such as the induction of radioresistance and the depression of radiation-induced apoptosis and chromosome aberrations were observed in wtp53 cells but not in mp53 cells. Conclusion: These results have confirmed the hypothesis that p53-dependent adaptive responses are apparently induced by space radiations within a specific range of low doses. The cells exhibited this effect owing to space radiations exposure, even though the doses in space were very low.

  18. Lymphocyte toxicity and T cell receptor excision circles in workers exposed to benzene.

    PubMed

    Lan, Qing; Zhang, Luoping; Hakim, Fran; Shen, Min; Memon, Sarfraz; Li, Guilan; Vermeulen, Roel; Smith, Martyn T; Rappaport, Stephen M; Hayes, Richard; Linet, Martha; Yin, Songnian; Rothman, Nathaniel; Rabkin, Charles S

    2005-05-30

    We have previously reported that benzene decreases peripheral white blood cell and platelet counts and specifically lowers subsets of several blood cell types, including CD4+-T cells, B cells, NK cells, and granulocytes. Diminished thymus function has been implicated as a mechanism for CD4+-T cell loss in other conditions such as AIDS by assays of T cell receptor excision circles (TRECs), a marker of naive T cells that have recently emigrated from the thymus. To evaluate alteration of thymic function as a mechanism for benzene's effects on CD4+-T cell counts, we measured total TREC levels in 45 benzene-exposed workers and 45 unexposed controls. There was no significant difference in TREC levels per 10(6) peripheral blood leukocytes in the benzene-exposed workers compared to the controls. Although our study does not rule out counterbalancing alterations of TREC levels in specific T cell subsets, benzene's lymphotoxicity does not appear to be mediated through diminished thymus function.

  19. Increased radioresistance of tumor cells exposed to metallothionein-inducing agents

    SciTech Connect

    Renan, M.J.; Dowman, P.I. )

    1989-12-01

    In this study, we have determined the radiosensitivity parameters of cells exposed in vitro to metallothionein-inducing agents. Three well-characterized tumor cell lines were chosen for investigation: HeLa, B16, and WHFIB. We have shown that exposure of cells in vitro to a heavy metal (cadmium), followed by irradiation, enhances cell survival for two out of three cell lines studied. As measured by the mean inactivation dose, the radioresistance increases by a factor of 1.6 for HeLa cells, 1.4 for WHFIB, and a negligible factor for B16 cells. An additional effect was noted when different classes of metallothionein inducers (such as serum factors, cadmium, and dexamethasone) were allowed to act together. Also, we found that the increase in radioresistance exhibits a peak at exposure times of approximately 10 h; longer exposure to inducing agents results in a reduction in radioresistance.

  20. In vitro metabolism study of normal and tumor cells when exposed to red LED light

    NASA Astrophysics Data System (ADS)

    Stolbovskaya, Olga V.; Khairullin, Radik M.; Saenko, Yuri V.; Krasnikova, Ekaterina S.; Krasnikov, Aleksandr V.; Fomin, Aleksandr A.; Skaptsov, Aleksandr A.

    2016-04-01

    This work presents the results of studying the mitochondrial membrane potential, intracellular ROS, peculiarities of the cell cycle of cancer cells HCT-116 and the normal line of CHO cells when exposed to the red LED light with a wavelength range of 0.620-0.680 μm. A dose-dependent increase in mitochondrial membrane potential and intracellular ROS concentration in cancer cells HCT-116 was established. In normal CHO cell line a dose-dependent reduction of mitochondrial membrane potential and dose-dependent increase in intracellular ROS occur. It has been shown that the sensitivity of the studied cell lines to the red light depends on the stage of the cell cycle.

  1. Increased Myeloid Cell Production and Lung Bacterial Clearance in Mice Exposed to Cigarette Smoke.

    PubMed

    Basilico, Paola; Cremona, Tiziana P; Oevermann, Anna; Piersigilli, Alessandra; Benarafa, Charaf

    2016-03-01

    Pneumonia is a leading cause of hospitalization in patients with chronic obstructive pulmonary disease (COPD). Although most patients with COPD are smokers, the effects of cigarette smoke exposure on clearance of lung bacterial pathogens and on immune and inflammatory responses are incompletely defined. Here, clearance of Streptococcus pneumoniae and Pseudomonas aeruginosa and associated immune responses were examined in mice exposed to cigarette smoke or after smoking cessation. Mice exposed to cigarette smoke for 6 weeks or 4 months demonstrated decreased lung bacterial burden compared with air-exposed mice when infected 16 to 24 hours after exposure. When infection was performed after smoke cessation, bacterial clearance kinetics of mice previously exposed to smoke reversed to levels comparable to those of control mice, suggesting that the observed defects were not dependent on adaptive immunological memory to bacterial determinants found in smoke. Comparing cytokine levels and myeloid cell production before infection in mice exposed to cigarette smoke with mice never exposed or after smoke cessation revealed that reduced bacterial burden was most strongly associated with higher levels of IL-1β and granulocyte-macrophage colony-stimulating factor in the lungs and with increased neutrophil reserve and monocyte turnover in the bone marrow. Using Serpinb1a-deficient mice with reduced neutrophil numbers and treatment with granulocyte colony-stimulating factor showed that increased neutrophil numbers contribute only in part to the effect of smoke on infection. Our findings indicate that cigarette smoke induces a temporary and reversible increase in clearance of lung pathogens, which correlates with local inflammation and increased myeloid cell output from the bone marrow.

  2. The transcriptome of HIV-1 infected intestinal CD4+ T cells exposed to enteric bacteria

    PubMed Central

    Dillon, Stephanie M.; Phang, Tzu; Lee, Eric J.; Helm, Karen; Kappes, John C.; McCarter, Martin D.

    2017-01-01

    Global transcriptome studies can help pinpoint key cellular pathways exploited by viruses to replicate and cause pathogenesis. Previous data showed that laboratory-adapted HIV-1 triggers significant gene expression changes in CD4+ T cell lines and mitogen-activated CD4+ T cells from peripheral blood. However, HIV-1 primarily targets mucosal compartments during acute infection in vivo. Moreover, early HIV-1 infection causes extensive depletion of CD4+ T cells in the gastrointestinal tract that herald persistent inflammation due to the translocation of enteric microbes to the systemic circulation. Here, we profiled the transcriptome of primary intestinal CD4+ T cells infected ex vivo with transmitted/founder (TF) HIV-1. Infections were performed in the presence or absence of Prevotella stercorea, a gut microbe enriched in the mucosa of HIV-1-infected individuals that enhanced both TF HIV-1 replication and CD4+ T cell death ex vivo. In the absence of bacteria, HIV-1 triggered a cellular shutdown response involving the downregulation of HIV-1 reactome genes, while perturbing genes linked to OX40, PPAR and FOXO3 signaling. However, in the presence of bacteria, HIV-1 did not perturb these gene sets or pathways. Instead, HIV-1 enhanced granzyme expression and Th17 cell function, inhibited G1/S cell cycle checkpoint genes and triggered downstream cell death pathways in microbe-exposed gut CD4+ T cells. To gain insights on these differential effects, we profiled the gene expression landscape of HIV-1-uninfected gut CD4+ T cells exposed to bacteria. Microbial exposure upregulated genes involved in cellular proliferation, MAPK activation, Th17 cell differentiation and type I interferon signaling. Our findings reveal that microbial exposure influenced how HIV-1 altered the gut CD4+ T cell transcriptome, with potential consequences for HIV-1 susceptibility, cell survival and inflammation. The HIV-1- and microbe-altered pathways unraveled here may serve as a molecular blueprint

  3. The Origin and Evolution of the Plant Cell Surface: Algal Integrin-Associated Proteins and a New Family of Integrin-Like Cytoskeleton-ECM Linker Proteins

    PubMed Central

    Becker, Burkhard; Doan, Jean Michel; Wustman, Brandon; Carpenter, Eric J.; Chen, Li; Zhang, Yong; Wong, Gane K.-S.; Melkonian, Michael

    2015-01-01

    The extracellular matrix of scaly green flagellates consists of small organic scales consisting of polysaccharides and scale-associated proteins (SAPs). Molecular phylogenies have shown that these organisms represent the ancestral stock of flagellates from which all green plants (Viridiplantae) evolved. The molecular characterization of four different SAPs is presented. Three SAPs are type-2 membrane proteins with an arginine/alanine-rich short cytoplasmic tail and an extracellular domain that is most likely of bacterial origin. The fourth protein is a filamin-like protein. In addition, we report the presence of proteins similar to the integrin-associated proteins α-actinin (in transcriptomes of glaucophytes and some viridiplants), LIM-domain proteins, and integrin-associated kinase in transcriptomes of viridiplants, glaucophytes, and rhodophytes. We propose that the membrane proteins identified are the predicted linkers between scales and the cytoskeleton. These proteins are present in many green algae but are apparently absent from embryophytes. These proteins represent a new protein family we have termed gralins for green algal integrins. Gralins are absent from embryophytes. A model for the evolution of the cell surface proteins in Plantae is discussed. PMID:25977459

  4. National Algal Biofuels Technology Roadmap

    SciTech Connect

    Ferrell, John; Sarisky-Reed, Valerie

    2010-05-01

    The framework for National Algal Biofuels Technology Roadmap was constructed at the Algal Biofuels Technology Roadmap Workshop, held December 9-10, 2008, at the University of Maryland-College Park. The Workshop was organized by the Biomass Program to discuss and identify the critical challenges currently hindering the development of a domestic, commercial-scale algal biofuels industry. This Roadmap presents information from a scientific, economic, and policy perspectives that can support and guide RD&D investment in algal biofuels. While addressing the potential economic and environmental benefits of using algal biomass for the production of liquid transportation fuels, the Roadmap describes the current status of algae RD&D. In doing so, it lays the groundwork for identifying challenges that likely need to be overcome for algal biomass to be used in the production of economically viable biofuels.

  5. α1-Antitrypsin reduces rhinovirus infection in primary human airway epithelial cells exposed to cigarette smoke.

    PubMed

    Berman, Reena; Jiang, Di; Wu, Qun; Chu, Hong Wei

    2016-01-01

    Human rhinovirus (HRV) infections target airway epithelium and are the leading cause of acute exacerbations of COPD. Cigarette smoke (CS) increases the severity of viral infections, but there is no effective therapy for HRV infection. We determined whether α1-antitrypsin (A1AT) reduces HRV-16 infection in CS-exposed primary human airway epithelial cells. Brushed bronchial epithelial cells from normal subjects and patients diagnosed with COPD were cultured at air-liquid interface to induce mucociliary differentiation. These cells were treated with A1AT or bovine serum albumin for 2 hours and then exposed to air or whole cigarette smoke (WCS) with or without HRV-16 (5×10(4) 50% Tissue Culture Infective Dose [TCID50]/transwell) infection for 24 hours. WCS exposure significantly increased viral load by an average of fivefold and decreased the expression of antiviral genes interferon-λ1, OAS1, and MX1. When A1AT was added to WCS-exposed cells, viral load significantly decreased by an average of 29-fold. HRV-16 infection significantly increased HRV-16 receptor intercellular adhesion molecule-1 messenger RNA expression in air-exposed cells, which was decreased by A1AT. A1AT-mediated reduction of viral load was not accompanied by increased epithelial antiviral gene expression or by inhibiting the activity of 3C protease involved in viral replication or maturation. Our findings demonstrate that A1AT treatment prevents a WCS-induced increase in viral load and for the first time suggest a therapeutic effect of A1AT on HRV infection.

  6. Advanced Algal Systems Fact Sheet

    SciTech Connect

    2016-06-01

    Research and development (R&D) on advanced algal biofuels and bioproducts presents an opportunity to sustainably expand biomass resource potential in the United States. The Bioenergy Technologies Office’s (BETO’s) Advanced Algal Systems Program is carrying out a long-term, applied R&D strategy to lower the costs of algal biofuel production by working with partners to develop revolutionary technologies and conduct crosscutting analyses to better understand the potential

  7. Dose-Dependent Metabolic Alterations in Human Cells Exposed to Gamma Irradiation

    PubMed Central

    Kwon, Yong-Kook; Ha, In Jin; Bae, Hyun-Whee; Jang, Won Gyo; Yun, Hyun Jin; Kim, So Ra; Lee, Eun Kyeong; Kang, Chang-Mo; Hwang, Geum-Sook

    2014-01-01

    Radiation exposure is a threat to public health because it causes many diseases, such as cancers and birth defects, due to genetic modification of cells. Compared with the past, a greater number of people are more frequently exposed to higher levels of radioactivity today, not least due to the increased use of diagnostic and therapeutic radiation-emitting devices. In this study, ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS)-based metabolic profiling was used to investigate radiation- induced metabolic changes in human fibroblasts. After exposure to 1 and 5 Gy of γ-radiation, the irradiated fibroblasts were harvested at 24, 48, and 72 h and subjected to global metabolite profiling analysis. Mass spectral peaks of cell extracts were analyzed by pattern recognition using principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA). The results showed that the cells irradiated with 1 Gy returned to control levels at 72 h post radiation, whereas cells irradiated with 5 Gy were quite unlike the controls; therefore, cells irradiated with 1 Gy had recovered, whereas those irradiated with 5 Gy had not. Lipid and amino acid levels increased after the higher-level radiation, indicating degradation of membranes and proteins. These results suggest that MS-based metabolite profiling of γ-radiation-exposed human cells provides insight into the global metabolic alterations in these cells. PMID:25419661

  8. Enhancement of algal growth and productivity by grazing zooplankton.

    PubMed

    Porter, K G

    1976-06-25

    Colonies of the common planktonic green alga, Sphaerocystis schroeteri, are only partially disrupted and assimilated by Daphnia magna, a natural predator. The Daphnia break up the outer protective gelatinous sheath that surrounds Sphaerocystis colonies, but most of the algal cells emerge from Daphnia guts intact and in viable condition. During gut passage, these viable cells take up nutrients, such as phosphorus, both from algal remains and from Daphnia metabolites. This nutrient supply stimulates algal carbon fixation and cell division. Enhanced algal growth, observed after gut passage, can compensate for the minor losses to the population caused by grazing. Nutrients regenerated by grazers may produce the summer bloom of gelatinous green algae during the seasonal succession of lake phytoplankton.

  9. DNA DAMAGE IN BUCCAL EPITHELIAL CELLS FROM INDIVIDUALS CHRONICALLY EXPOSED TO ARSENIC VIA DRINKING WATER IN INNER MONGOLIA, CHINA

    EPA Science Inventory

    The purpose of this pilot study was to assess DNA damage in buccal cells from individuals chronically exposed to arsenic via drinking water in Ba Men, Inner Mongolia. Buccal cells were collected from 19 Ba Men residents exposed to arsenic at 527.5 ? 23.7 g/L (mean ? SEM) and ...

  10. Noise induced calcium oscillations in a cell exposed to electromagnetic fields.

    PubMed

    Zhang, Yuhong; Zhao, Yongli; Chen, Yafei; Yuan, Changqing; Zhan, Yong

    2015-01-01

    The effects of noise on the calcium oscillations in a cell exposed to electromagnetic fields are described by a dynamic model. Noise is a very important factor to be considered in the dynamic research on the calcium oscillations in a cell exposed to electromagnetic fields. Some meaningful results have been obtained here based on the discussion. The results show that the pattern of intracellular calcium oscillations exposure to electromagnetic fields can be influenced by noise. Furthermore, the intracellular calcium oscillations exposure to electromagnetic fields can also be induced by noise. And the work has also studied the relationships between the voltage sensitive calcium channel's open probability and electromagnetic field. The result can provide new insights into constructive roles and potential applications of selecting appropriate electromagnetic field frequency during the research of biological effect of electromagnetic field.

  11. Structural and function changes in organelles of liver cells in rats exposed to magnetic fields

    SciTech Connect

    Gorczynska, E. ); Wegrzynowicz, R. )

    1991-08-01

    Exposure of rats to magnetic fields of 10{sup {minus}3} and 10{sup {minus}2} T for 1 hr daily generated structural changes in hepatocytes mitochondria, endoplasmic reticulum, and ribosomes. Simultaneously there was an increase in the activities of the mitochondrial respiratory enzymes: NADH dehydrogenase, succinic dehydrogenase, and cytochrome oxidase. The extent of the changes in liver cell properties following exposure depend on the duration of exposure to and the strength of the applied magnetic fields. Ultrastructural studies did not reveal any changes in external membranes of hepatocytes or in the membranes of cell nuclei. An increase in the amount of glycogen in hepatocytes of rats exposed to both 10{sup {minus}3} and 10{sup {minus}2} T was noted. The high level of cortisol in serum of exposed rats suggests that magnetic field may be a stress generating factor.

  12. Recent Advances in Algal Genetic Tool Development

    DOE PAGES

    R. Dahlin, Lukas; T. Guarnieri, Michael

    2016-06-24

    The goal of achieving cost-effective biofuels and bioproducts derived from algal biomass will require improvements along the entire value chain, including identification of robust, high-productivity strains and development of advanced genetic tools. Though there have been modest advances in development of genetic systems for the model alga Chlamydomonas reinhardtii, progress in development of algal genetic tools, especially as applied to non-model algae, has generally lagged behind that of more commonly utilized laboratory and industrial microbes. This is in part due to the complex organellar structure of algae, including robust cell walls and intricate compartmentalization of target loci, as well asmore » prevalent gene silencing mechanisms, which hinder facile utilization of conventional genetic engineering tools and methodologies. However, recent progress in global tool development has opened the door for implementation of strain-engineering strategies in industrially-relevant algal strains. Here, we review recent advances in algal genetic tool development and applications in eukaryotic microalgae.« less

  13. Reduced cytotoxicity in PCB-exposed Chinese Hamster Ovary (CHO) cells pretreated with vitamin E.

    PubMed

    Murati, Teuta; Šimić, Branimir; Pleadin, Jelka; Vukmirović, Maja; Miletić, Marina; Durgo, Ksenija; Kniewald, Jasna; Kmetič, Ivana

    2017-01-01

    The aim of this study was to evaluate protective effects of vitamin E (50 -150 μM) in ovary cells upon cytotoxic effects induced by two structurally distinct PCB congeners - planar "dioxin-like" PCB 77 and non-planar di-ortho-substituted PCB 153 with an emphasis on identifying differences in the mechanism of vitamin E action depending on the structure of congeners. Application of three bioassays confirmed that PCBs decrease ovarian cell proliferation with slightly profound effects of PCB 77. PCB - induced ROS production and lipid peroxidation were significant for both congeners with also more noticeable effect for PCB 77. Vitamin E pre-incubation has improved viability of cells, reduced ROS formation and lipid peroxidation induced by PCBs' treatment. Preincubation with vitamin E was more effective when cells where treated with non-planar PCB 153. Altogether, vitamin E action was protective, congener specific and more effective when ovary cells were exposed to ortho-substituted PCB congener.

  14. Algal biofuels from wastewater treatment high rate algal ponds.

    PubMed

    Craggs, R J; Heubeck, S; Lundquist, T J; Benemann, J R

    2011-01-01

    This paper examines the potential of algae biofuel production in conjunction with wastewater treatment. Current technology for algal wastewater treatment uses facultative ponds, however, these ponds have low productivity (∼10 tonnes/ha.y), are not amenable to cultivating single algal species, require chemical flocculation or other expensive processes for algal harvest, and do not provide consistent nutrient removal. Shallow, paddlewheel-mixed high rate algal ponds (HRAPs) have much higher productivities (∼30 tonnes/ha.y) and promote bioflocculation settling which may provide low-cost algal harvest. Moreover, HRAP algae are carbon-limited and daytime addition of CO(2) has, under suitable climatic conditions, the potential to double production (to ∼60 tonnes/ha.y), improve bioflocculation algal harvest, and enhance wastewater nutrient removal. Algae biofuels (e.g. biogas, ethanol, biodiesel and crude bio-oil), could be produced from the algae harvested from wastewater HRAPs, The wastewater treatment function would cover the capital and operation costs of algal production, with biofuel and recovered nutrient fertilizer being by-products. Greenhouse gas abatement results from both the production of the biofuels and the savings in energy consumption compared to electromechanical treatment processes. However, to achieve these benefits, further research is required, particularly the large-scale demonstration of wastewater treatment HRAP algal production and harvest.

  15. Adrenal chromaffin cells do not swell when exposed to nanosecond electric pulses.

    PubMed

    Craviso, Gale L; Fisher, Christa; Chatterjee, Indira; Vernier, P Thomas

    2015-06-01

    High intensity, nanosecond duration electric pulses (NEPs) permeabilize plasma membranes causing osmotic cell swelling that can elicit a wide variety of cellular effects. This study examined the possibility that cell swelling is the mechanism by which 5 ns NEPs trigger the release of catecholamines from neuroendocrine adrenal chromaffin cells. Swelling was assessed by comparing measurements of cell area obtained from bright field images of the cells before and at 10s intervals following exposure of the cells to 5 ns pulses at a field intensity of 5-6 MV/m. The results indicated that chromaffin cells do not swell in response to a single pulse or a train of ten pulses delivered at repetition frequencies of 10 Hz and 1 kHz. Swelling was also not observed in response to a train of 50 pulses whereas Jurkat T lymphoblast cell area increased 15% on average under the same NEP exposure conditions. These results demonstrating that chromaffin cells do not undergo swelling when exposed to 5 ns NEPs have important implications regarding the mechanism by which these pulses stimulate the release of catecholamines from these cells, namely that catecholamine secretion is most likely not caused by cell swelling.

  16. Mechanisms of mutagenesis in human cells exposed to 55 MeV protons

    NASA Technical Reports Server (NTRS)

    Gauny, S.; Wiese, C.; Kronenberg, A.

    2001-01-01

    Protons represent the major type of charged particle radiation in spaceflight environments. The purpose of this study was to assess mutations arising in human lymphoid cells exposed to protons. Mutations were quantitated at the thymidine kinase (TK1) locus in cell lines derived from the same donor: TK6 cells (wt TP53) and WTK1 cells (mutant TP53). WTK1 cells were much more susceptible to mutagenesis following proton exposure than TK6 cells. Intragenic deletions were observed among early-arising TK1 mutants in TK6 cells, but not in WTK1 cells where all of the mutants arose by LOH. Deletion was the predominant mode of LOH in TK6 cells, while allelic recombination was the major mode of LOH in WTK1 cells. Deletions were of variable lengths, from <1 cM to 64 cM, while mutations that arose by allelic recombination often extended to the telomere. In summary, proton exposures elicited many types of mutations at an autosomal locus in human cells. Most involved large scale loss of genetic information, either through deletion or by recombination.

  17. Effects of solar ultraviolet radiation on tropical algal communities

    SciTech Connect

    Santas, R.

    1989-01-01

    This study assessed some of the effects of solar ultraviolet (UV) radiation ion coral reef algal assemblages. The first part of the investigation was carried out under controlled laboratory conditions in the coral reef microcosm at the National Museum of Natural History in Washington, D.C., while a field counterpart was completed at the Smithsonian Institution's marine station on Grand Turk, Turks and Caicos Islands, in the eastern Caribbean. The study attempted to separate the effects of UV-A from those of UV-B. In the laboratory, algal turf assemblages exposed to simulated solar UV radiation produced 55.1% less biomass than assemblages that were not exposed to UV. Assemblages not exposed to UV were dominated by Ectocarpus rhodochondroides, whereas in the assemblage developing under high UV radiation, Enteromorpha prolifera and eventually Schizothrix calcicola dominated. Lower UV-B irradiances caused a proportional reduction in biomass production and had less pronounced effects on species composition. UV-A did not have any significant effects on either algal turf productivity or community structure. In the field, assemblages exposed to naturally occurring solar UV supported a biomass 40% lower than that of assemblages protected from UV-B exposure. Once again, UV-A did not inhibit algal turf productivity.

  18. Immune recognition of exposed xenoantigens on the surface of PEGylated bovine red blood cells.

    PubMed

    Gundersen, Sharon I; Kennedy, Melanie S; Palmer, Andre F

    2008-10-01

    Due to potential problems that can occur during blood transfusion and increasing blood shortages, our group engineered methoxypolyethylene glycol conjugated bovine red blood cells (mPEG-bRBCs) as a potential universal oxygen therapeutic. This current work investigates the immunological properties of mPEG-bRBCs incubated with human plasma (hP) and correlates these properties to exposed Galalpha(1,3)Gal xenoantigens. After mPEG-bRBCs were incubated with hP, the amount of bound IgG and IgM was assessed via flow cytometry. Flow cytometry also assessed the amount of GS-IB4 bound to exposed Galalpha(1,3)Gal xenoantigens. The results of this study demonstrate that most hP samples strongly promote agglutination of mPEG-bRBCs regardless of the extent of mPEG surface coverage or donor blood type. IgG and IgM from hP bound strongly to mPEG-bRBCs. In general, the Galalpha(1,3)Gal xenoantigen remains exposed at all levels of PEG surface coverage. PEGylation did block some of the xenoantigens as the amount of exposed Galalpha (1,3)Gal decreased with increased mPEG surface coverage. However, this was not sufficient to prevent a strong agglutination reaction. Taken together, the results of this study indicate that the current strategy for PEGylating bRBCs is unsatisfactory for the development of immunologically silent oxygen therapeutics.

  19. Identification of gene-based responses in human blood cells exposed to alpha particle radiation

    PubMed Central

    2014-01-01

    Background The threat of a terrorist-precipitated nuclear event places humans at danger for radiological exposures. Isotopes which emit alpha (α)-particle radiation pose the highest risk. Currently, gene expression signatures are being developed for radiation biodosimetry and triage with respect to ionizing photon radiation. This study was designed to determine if similar gene expression profiles are obtained after exposures involving α-particles. Methods Peripheral blood mononuclear cells (PBMCs) were used to identify sensitive and robust gene-based biomarkers of α-particle radiation exposure. Cells were isolated from healthy individuals and were irradiated at doses ranging from 0-1.5 Gy. Microarray technology was employed to identify transcripts that were differentially expressed relative to unirradiated cells 24 hours post-exposure. Statistical analysis identified modulated genes at each of the individual doses. Results Twenty-nine genes were common to all doses with expression levels ranging from 2-10 fold relative to control treatment group. This subset of genes was further assessed in independent complete white blood cell (WBC) populations exposed to either α-particles or X-rays using quantitative real-time PCR. This 29 gene panel was responsive in the α-particle exposed WBCs and was shown to exhibit differential fold-changes compared to X-irradiated cells, though no α-particle specific transcripts were identified. Conclusion Current gene panels for photon radiation may also be applicable for use in α-particle radiation biodosimetry. PMID:25017500

  20. Effects of selenocystine on lead-exposed Chinese hamster ovary (CHO) and PC-12 cells

    SciTech Connect

    Aykin-Burns, Nukhet; Ercal, Nuran . E-mail: nercal@umr.edu

    2006-07-15

    Lead is a pervasive environmental toxin that affects multiple organ systems, including the nervous, renal, reproductive, and hematological systems. Even though it is probably the most studied toxic metal, some of the symptoms of lead toxicity still cannot be explained by known molecular mechanisms. Therefore, lead-induced oxidative stress has recently started to gain attention. This in vitro study confirms the existence of oxidative stress due to lead exposure. Administration of lead acetate (PbA) to cultures of Chinese hamster ovary cells (CHO) had a concentration-dependent inhibitory effect on colony formation and cell proliferation. This inhibition was eliminated by 5 {mu}M selenocystine (SeCys). In order to evaluate the nature of SeCys's effect, we measured glutathione (GSH), its oxidized form glutathione disulfide (GSSG), malondialdehyde (MDA), catalase, and GSH peroxidase (GPx) activities in lead-exposed CHO cells both in the presence and absence of SeCys. Increases in MDA, catalase, and GPx activities were observed in cultures that received only PbA, but supplementation with SeCys returned these measures to pretreatment levels. The ratio of GSH to GSSG increased in lead-exposed cells incubated in SeCys-enhanced media but declined in cultures treated with PbA only. In order to determine whether SeCys also reverses lead-induced neurotoxicity, a neuronal cell line, PC-12 cells, was used. Lead's inhibition on neurite formation was significantly eliminated by SeCys in PC-12 cells. Our results suggest that SeCys can confer protection against lead-induced toxicity in CHO cells and neurotoxicity in PC-12 cells.

  1. High resolution imaging of the ultrastructure of living algal cells using soft x-ray contact microscopy

    SciTech Connect

    Ford, T.W.; Cotton, R.A.; Page, A.M.; Tomie, T.; Majima, T.; Stead, A.D.

    1995-12-31

    Soft x-ray contact microscopy provides the biologist with a technique for examining the ultrastructure of living cells at a much higher resolution than that possible by various forms of light microscopy. Readout of the developed photoresist using atomic force microscopy (AFM) produces a detailed map of the carbon densities generated in the resist following exposure of the specimen to water-window soft x-rays (2--4nm) produced by impact of a high energy laser onto a suitable target. The established high resolution imaging method of transmission electron microscopy (TEM) has inherent problems in the chemical pre-treatment required for producing the ultrathin sections necessary for this technique. Using the unicellular green alga Chlamydomonas the ultrastructural appearance of the cells following SXCM and TEM has been compared. While SXCM confirms the basic structural organization of the cell as seen by TEM (e.g., the organization of the thylakoid membranes within the chloroplast; flagellar insertion into the cytoplasm), there are important differences. These are in the appearance of the cell covering and the presence of carbon-dense spherical cellular inclusions.

  2. Cell surface differences of Naegleria fowleri and Naegleria lovaniensis exposed with surface markers.

    PubMed

    González-Robles, Arturo; Castañón, Guadalupe; Cristóbal-Ramos, Ana Ruth; Hernández-Ramírez, Verónica Ivonne; Omaña-Molina, Maritza; Martínez-Palomo, Adolfo

    2007-12-01

    Differences in the distribution of diverse cell surface coat markers were found between Naegleria fowleri and Naegleria lovaniensis. The presence of carbohydrate-containing components in the cell coat of the two species was detected by selective staining with ruthenium red and alcian blue. Using both markers, N. fowleri presented a thicker deposit than N. lovaniensis. The existence of exposed mannose or glucose residues was revealed by discriminatory agglutination with the plant lectin Concanavalin A. These sugar residues were also visualized at the cell surface of these parasites either by transmission electron microscopy or by fluorescein-tagged Concanavalin A. Using this lectin cap formation was induced only in N. fowleri. The anionic sites on the cell surface detected by means of cationized ferritin were more apparent in N. fowleri. Biotinylation assays confirmed that even though the two amoebae species have some analogous plasma membrane proteins, there is a clear difference in their composition.

  3. Assessment of DNA integrity (COMET assay) in sperm cells of boron-exposed workers.

    PubMed

    Duydu, Yalçin; Başaran, Nurşen; Ustündağ, Aylin; Aydin, Sevtap; Undeğer, Ulkü; Ataman, Osman Yavuz; Aydos, Kaan; Düker, Yalçin; Ickstadt, Katja; Waltrup, Britta Schulze; Golka, Klaus; Bolt, Hermann M

    2012-01-01

    An extension of a male reproductive study conducted in a boric acid/borate production zone at Bandırma, Turkey, is presented. The relation between DNA-strand breaks (COMET assay, neutral and alkaline version) in sperm cells and previously described sperm quality parameters was investigated in boron-exposed males. A correlation between blood boron levels and mean DNA-strand breaks in sperm was weak, and DNA-strand breaks in sperm were statistically not different between control and exposed groups. Therefore, increasing boron exposures had no additional contribution in addition to already pre-existing DNA-strand breaks in the sperm cells. Weak but statistically significant correlations between DNA-strand breaks and motility/morphology parameters of sperm samples were observed in the neutral version of the COMET assay, while correlations between the same variables were statistically not significant in the alkaline version. A likely reason for these negative results, even in highly exposed humans, is that experimental exposures that had led to reproductive toxicity in animals were significantly higher than any boron exposures, which may be reached under realistic human conditions.

  4. Dose- and Time-Dependent Transcriptional Response of Ishikawa Cells Exposed to Genistein.

    PubMed

    Naciff, Jorge M; Khambatta, Zubin S; Carr, Gregory J; Tiesman, Jay P; Singleton, David W; Khan, Sohaib A; Daston, George P

    2016-05-01

    To further define the utility of the Ishikawa cells as a reliable in vitro model to determine the potential estrogenic activity of chemicals of interest, transcriptional changes induced by genistein (GES) in Ishikawa cells at various doses (10 pM, 1 nM, 100 nM, and 10 μM) and time points (8, 24, and 48 h) were identified using a comprehensive microarray approach. Trend analysis indicated that the expression of 5342 unique genes was modified by GES in a dose- and time-dependent manner (P ≤ 0.0001). However, the majority of gene expression changes induced in Ishikawa cells were elicited by the highest dose of GES evaluated (10 μM). The GES' estrogenic activity was identified by comparing the Ishikawa cells' response to GES versus 17 α-ethynyl estradiol (EE, at equipotent doses, ie, 10 μM vs 1 μM, respectively) and was defined by changes in the expression of 284 unique genes elicited by GES and EE in the same direction, although the magnitude of the change for some genes was different. Further, comparing the response of the Ishikawa cells exposed to high doses of GES and EE versus the response of the juvenile rat uterus exposed to EE, we identified 66 unique genes which were up- or down regulated in a similar manner in vivo as well as in vitro Genistein elicits changes in multiple molecular pathways affecting various biological processes particularly associated with cell organization and biogenesis, regulation of translation, cell proliferation, and intracellular transport; processes also affected by estrogen exposure in the uterus of the rat. These results indicate that Ishikawa cells are capable of generating a biologically relevant estrogenic response and offer an in vitro model to assess this mode of action.

  5. Concurrent Exposure of Bottlenose Dolphins (Tursiops truncatus) to Multiple Algal Toxins in Sarasota Bay, Florida, USA

    PubMed Central

    Twiner, Michael J.; Fire, Spencer; Schwacke, Lori; Davidson, Leigh; Wang, Zhihong; Morton, Steve; Roth, Stephen; Balmer, Brian; Rowles, Teresa K.; Wells, Randall S.

    2011-01-01

    Sentinel species such as bottlenose dolphins (Tursiops truncatus) can be impacted by large-scale mortality events due to exposure to marine algal toxins. In the Sarasota Bay region (Gulf of Mexico, Florida, USA), the bottlenose dolphin population is frequently exposed to harmful algal blooms (HABs) of Karenia brevis and the neurotoxic brevetoxins (PbTx; BTX) produced by this dinoflagellate. Live dolphins sampled during capture-release health assessments performed in this region tested positive for two HAB toxins; brevetoxin and domoic acid (DA). Over a ten-year study period (2000–2009) we have determined that bottlenose dolphins are exposed to brevetoxin and/or DA on a nearly annual basis (i.e., DA: 2004, 2005, 2006, 2008, 2009; brevetoxin: 2000, 2004, 2005, 2008, 2009) with 36% of all animals testing positive for brevetoxin (n = 118) and 53% positive for DA (n = 83) with several individuals (14%) testing positive for both neurotoxins in at least one tissue/fluid. To date there have been no previously published reports of DA in southwestern Florida marine mammals, however the May 2008 health assessment coincided with a Pseudo-nitzschia pseudodelicatissima bloom that was the likely source of DA observed in seawater and live dolphin samples. Concurrently, both DA and brevetoxin were observed in common prey fish. Although no Pseudo-nitzschia bloom was identified the following year, DA was identified in seawater, fish, sediment, snails, and dolphins. DA concentrations in feces were positively correlated with hematologic parameters including an increase in total white blood cell (p = 0.001) and eosinophil (p<0.001) counts. Our findings demonstrate that dolphins within Sarasota Bay are commonly exposed to two algal toxins, and provide the impetus to further explore the potential long-term impacts on bottlenose dolphin health. PMID:21423740

  6. Recycling algae to improve species control and harvest efficiency from a high rate algal pond.

    PubMed

    Park, J B K; Craggs, R J; Shilton, A N

    2011-12-15

    This paper investigates the influence of recycling gravity harvested algae on species dominance and harvest efficiency in wastewater treatment High Rate Algal Ponds (HRAP). Two identical pilot-scale HRAPs were operated over one year either with (HRAP(r)) or without (HRAP(c)) harvested algal biomass recycling. Algae were harvested from the HRAP effluent in algal settling cones (ASCs) and harvest efficiency was compared to settlability in Imhoff cones five times a week. A microscopic image analysis technique was developed to determine relative algal dominance based on biovolume and was conducted once a month. Recycling of harvested algal biomass back to the HRAP(r) maintained the dominance of a single readily settleable algal species (Pediastrum sp.) at >90% over one year (compared to the control with only 53%). Increased dominance of Pediastrum sp. greatly improved the efficiency of algal harvest (annual average of >85% harvest for the HRAP(r) compared with ∼60% for the control). Imhoff cone experiments demonstrated that algal settleability was influenced by both the dominance of Pediastrum sp. and the species composition of remaining algae. Algal biomass recycling increased the average size of Pediastrum sp. colonies by 13-30% by increasing mean cell residence time. These results indicate that recycling gravity harvested algae could be a simple and effective operational strategy to maintain the dominance of readily settleable algal species, and enhance algal harvest by gravity sedimentation.

  7. Workers exposed to wood dust have an increased micronucleus frequency in nasal and buccal cells: results from a pilot study.

    PubMed

    Bruschweiler, Evin Danisman; Hopf, Nancy B; Wild, Pascal; Huynh, Cong Khanh; Fenech, Michael; Thomas, Philip; Hor, Maryam; Charriere, Nicole; Savova-Bianchi, Dessislava; Danuser, Brigitta

    2014-05-01

    Wood dust is recognised as a human carcinogen, based on the strong association of wood dust exposure and the elevated risk of malignant tumours of the nasal cavity and paranasal sinuses [sino-nasal cancer (SNC)]. The study aimed to assess genetic damage in workers exposed to wood dust using biomarkers in both buccal and nasal cells that reflect genome instability events, cellular proliferation and cell death frequencies. Nasal and buccal epithelial cells were collected from 31 parquet layers, installers, carpenters and furniture workers (exposed group) and 19 non-exposed workers located in Switzerland. Micronucleus (MN) frequencies were scored in nasal and buccal cells collected among woodworkers. Other nuclear anomalies in buccal cells were measured through the use of the buccal micronucleus cytome assay. MN frequencies in nasal and buccal cells were significantly higher in the exposed group compared to the non-exposed group; odds ratio for nasal cells 3.1 [95% confidence interval (CI) 1.8-5.1] and buccal cells 1.8 (95% CI 1.3-2.4). The exposed group had higher frequencies of cells with nuclear buds, karyorrhectic, pyknotic, karyolytic cells and a decrease in the frequency of basal, binucleated and condensed cells compared to the non-exposed group. Our study confirms that woodworkers have an elevated risk for chromosomal instability in cells of the aerodigestive tract. The MN assay in nasal cells may become a relevant biomonitoring tool in the future for early detection of SNC risk. Future studies should seek to standardise the protocol for MN frequency in nasal cells similar to that for MN in buccal cells.

  8. Endothelial dysfunction and monocyte recruitment in cells exposed to non-uniform shear stress.

    PubMed

    Cicha, Iwona; Goppelt-Struebe, Margarete; Yilmaz, Atilla; Daniel, Werner G; Garlichs, Christoph D

    2008-01-01

    Atherosclerosis results from a combination of local blood flow patterns and systemic risk factors. We investigated whether non-uniform shear stress at bifurcations induces pro-atherogenic endothelial dysfunction and monocyte recruitment. Bifurcating flow-through cell culture slides were used to expose HUVECs to laminar or non-uniform shear stress for 18 h at 10 dyne/cm(2). For the adhesion assay, HUVECs were subsequently perfused with medium containing THP-1 monocytes for 1 h. Protein expression was determined by immunofluorescence. In areas exposed to laminar shear stress, alignment of endothelial cells with the flow was observed, accompanied by upregulation of eNOS and downregulation of connective tissue growth factor (CTGF). In contrast, cells exposed to non-uniform shear stress near the outer walls of bifurcations were characterized by irregular, unaligned shape, induction of endothelin-1 and CTGF, as well as reduced eNOS expression. These atherogenic effects of non-uniform shear stress were prevented when cells were treated with statins (1 mumol/l) during flow. Under non-uniform shear stress, a slight induction of VCAM-1, ICAM-1, and E-/P-selectin was observed. In agreement with this, monocyte recruitment, which was nearly undetectable under laminar shear stress, was moderately induced by non-uniform shear stress (P<0.02). In conclusion, inhibition of antioxidative eNOS and upregulation of atherogenic proteins is the first step in non-uniform shear stress-mediated endothelial dysfunction, which in vivo in the presence of atherogenic risk factors may further enhance monocyte recruitment into the artery wall.

  9. Chromosomal Aberrations in Normal and AT Cells Exposed to High Dose of Low Dose Rate Irradiation

    NASA Technical Reports Server (NTRS)

    Kawata, T.; Shigematsu, N.; Kawaguchi, O.; Liu, C.; Furusawa, Y.; Hirayama, R.; George, K.; Cucinotta, F.

    2011-01-01

    Ataxia telangiectasia (A-T) is a human autosomally recessive syndrome characterized by cerebellar ataxia, telangiectases, immune dysfunction, and genomic instability, and high rate of cancer incidence. A-T cell lines are abnormally sensitive to agents that induce DNA double strand breaks, including ionizing radiation. The diverse clinical features in individuals affected by A-T and the complex cellular phenotypes are all linked to the functional inactivation of a single gene (AT mutated). It is well known that cells deficient in ATM show increased yields of both simple and complex chromosomal aberrations after high-dose-rate irradiation, but, less is known on how cells respond to low-dose-rate irradiation. It has been shown that AT cells contain a large number of unrejoined breaks after both low-dose-rate irradiation and high-dose-rate irradiation, however sensitivity for chromosomal aberrations at low-dose-rate are less often studied. To study how AT cells respond to low-dose-rate irradiation, we exposed confluent normal and AT fibroblast cells to up to 3 Gy of gamma-irradiation at a dose rate of 0.5 Gy/day and analyzed chromosomal aberrations in G0 using fusion PCC (Premature Chromosomal Condensation) technique. Giemsa staining showed that 1 Gy induces around 0.36 unrejoined fragments per cell in normal cells and around 1.35 fragments in AT cells, whereas 3Gy induces around 0.65 fragments in normal cells and around 3.3 fragments in AT cells. This result indicates that AT cells can rejoin breaks less effectively in G0 phase of the cell cycle? compared to normal cells. We also analyzed chromosomal exchanges in normal and AT cells after exposure to 3 Gy of low-dose-rate rays using a combination of G0 PCC and FISH techniques. Misrejoining was detected in the AT cells only? When cells irradiated with 3 Gy were subcultured and G2 chromosomal aberrations were analyzed using calyculin-A induced PCC technique, the yield of unrejoined breaks decreased in both normal and AT

  10. Cytoprotective effect of lacritin on human corneal epithelial cells exposed to benzalkonium chloride in vitro

    PubMed Central

    Feng, Mary M.; Baryla, Julia; Liu, Hong; Laurie, Gordon W.; McKown, Robert L.; Ashki, Negin; Bhayana, Dinesh

    2015-01-01

    Purpose Benzalkonium chloride (BAK) is the most commonly found preservative in eye drops, and has been shown to cause ocular surface inflammation and toxicity. Lacritin is a human tear glycoprotein secreted from the lacrimal glands that has been found to be cytoprotective. This study was designed to determine if the presence of lacritin confers protection to a cultured human corneal epithelial (HCE) cell line, CRL-11515, and primary HCE cells after exposure to the ocular preservative agent BAK. Materials and Methods Recombinant human lacritin was cloned into intein fusion vectors, expressed in E. coli, and purified on chitin beads and DEAE Sepharose. Metabolic curves were established using the MTT assay after exposure of subconfluent CRL-11515 cells to BAK or lacritin. Western blot analysis of lipidated LC3 (LC3-II) provided a measure of autophagy in CRL-11515 cells exposed to lacritin and/or BAK. Results BAK reduced CRL-11515 cellular metabolic activity in a time and dose dependent manner. BAK-induced cellular stress was evident by elevated autophagy that increased with rising concentrations of BAK compared to control (P < 0.05). Lacritin increased HCE cell proliferation at an optimal dose of 1 nM. Preconditioning HCE cells with 1 nM lacritin for 24 hours prior to BAK exposure significantly dampened levels of LC3-II (P < 0.05) and promoted a significant increase in cellular metabolic activity (P < 0.01) compared to BAK alone. Conclusions These results suggest lacritin protects cultured HCE cells stressed with BAK. Lacritin may have the potential to be used as a topical adjunctive therapy in eyes chronically exposed to BAK. PMID:24401093

  11. Insights on cryoprotectant toxicity from gene expression profiling of endothelial cells exposed to ethylene glycol.

    PubMed

    Cordeiro, Rui Martins; Stirling, Soren; Fahy, Gregory M; de Magalhães, João Pedro

    2015-12-01

    Cryopreservation consists of preserving living cells or tissues generally at -80 °C or below and has many current applications in cell and tissue banking, and future potential for organ banking. Cryoprotective agents such as ethylene glycol (EG) are required for successful cryopreservation of most living systems, but have toxic side effects whose mechanisms remain largely unknown. In this work, we investigated the mechanisms of toxicity of ethylene glycol in human umbilical vein endothelial cells (HUVECs) as a model of the vascular endothelium in perfused organs. Exposing cells to 60% v/v EG for 2 h at 4 °C resulted in only a slight decrease in subsequent cell growth, suggesting only modest toxicity of EG for this cell type. Gene expression analysis with whole genome microarrays revealed signatures indicative of a generalized stress response at 24 h after EG exposure and a trend toward partial recovery at 72 h. The observed changes involved signalling pathways, glycoproteins, and genes involved in extracellular and transmembrane functions, the latter suggesting potential effects of ethylene glycol on membranes. These results continue to develop a new paradigm for understanding cryoprotectant toxicity and reveal molecular signatures helpful for future experiments in more completely elucidating the toxic effects of ethylene glycol in vascular endothelial cells and other cell types.

  12. Single Walled Carbon Nanotubes Exhibit Dual-Phase Regulation to Exposed Arabidopsis Mesophyll Cells

    PubMed Central

    2011-01-01

    Herein we are the first to report that single-walled carbon nanotubes (SWCNTs) exhibit dual-phase regulation to Arabidopsis mesophyll cells exposed to different concentration of SWCNTs. The mesophyll protoplasts were prepared by enzyme digestion, and incubated with 15, 25, 50, 100 μg/ml SWCNTs for 48 h, and then were observed by optical microscopy and transmission electron microscopy, the reactive oxygen species (ROS) generation was measured. Partial protoplasts were stained with propidium iodide and 4'-6- diamidino-2-phenylindole, partial protoplasts were incubated with fluorescein isothiocyanate-labeled SWCNTs, and observed by fluorescence microscopy. Results showed that SWCNTs could traverse both the plant cell wall and cell membrane, with less than or equal to 50 μg/ml in the culture medium, SWCNTs stimulated plant cells to grow out trichome clusters on their surface, with more than 50 μg/ml SWCNTs in the culture medium, SWCNTs exhibited obvious toxic effects to the protoplasts such as increasing generation of ROS, inducing changes of protoplast morphology, changing green leaves into yellow, and inducing protoplast cells' necrosis and apoptosis. In conclusion, single walled carbon nanotubes can get through Arabidopsis mesophyll cell wall and membrane, and exhibit dose-dependent dual-phase regulation to Arabidopsis mesophyll protoplasts such as low dose stimulating cell growth, and high dose inducing cells' ROS generation, necrosis or apoptosis. PMID:27502666

  13. Creatine as a compatible osmolyte in muscle cells exposed to hypertonic stress

    PubMed Central

    Alfieri, Roberta R; Bonelli, Mara A; Cavazzoni, Andrea; Brigotti, Maurizio; Fumarola, Claudia; Sestili, Piero; Mozzoni, Paola; De Palma, Giuseppe; Mutti, Antonio; Carnicelli, Domenica; Vacondio, Federica; Silva, Claudia; Borghetti, Angelo F; Wheeler, Kenneth P; Petronini, Pier Giorgio

    2006-01-01

    Exposure of C2C12 muscle cells to hypertonic stress induced an increase in cell content of creatine transporter mRNA and of creatine transport activity, which peaked after about 24 h incubation at 0.45 osmol (kg H2O)−1. This induction of transport activity was prevented by addition of either cycloheximide, to inhibit protein synthesis, or of actinomycin D, to inhibit RNA synthesis. Creatine uptake by these cells is largely Na+ dependent and kinetic analysis revealed that its increase under hypertonic conditions resulted from an increase in Vmax of the Na+-dependent component, with no significant change in the Km value of about 75 μmol l−1. Quantitative real-time PCR revealed a more than threefold increase in the expression of creatine transporter mRNA in cells exposed to hypertonicity. Creatine supplementation significantly enhanced survival of C2C12 cells incubated under hypertonic conditions and its effect was similar to that obtained with the well known compatible osmolytes, betaine, taurine and myo-inositol. This effect seemed not to be linked to the energy status of the C2C12 cells because hypertonic incubation caused a decrease in their ATP content, with or without the addition of creatine at 20 mmol l−1 to the medium. This induction of creatine transport activity by hypertonicity is not confined to muscle cells: a similar induction was shown in porcine endothelial cells. PMID:16873409

  14. Enhanced performance of an air-cathode microbial fuel cell with oxygen supply from an externally connected algal bioreactor.

    PubMed

    Kakarla, Ramesh; Kim, Jung Rae; Jeon, Byong-Hun; Min, Booki

    2015-11-01

    An algae bioreactor (ABR) was externally connected to air-cathode microbial fuel cells (MFCs) to increase power generation by supplying a high amount of oxygen to cathode electrode. The MFC with oxygen fed from ABR produced maximum cell voltage and cathode potential at a fixed loading of 459 mV and 10 mV, respectively. During polarization analysis, the MFC displayed a maximum power density of 0.63 W/m(2) (at 2.06 A/m(2)) using 39.2% O2 from ABR, which was approximately 30% higher compared with use of atmospheric air (0.44 W/m(2), 20.8% O2,). The cyclic voltammogram analysis exhibited a higher reduction current of -137 mA with 46.5% O2 compared to atmospheric air (-115 mA). Oxygen supply by algae bioreactor to air-cathode MFC could also maintain better MFC performance in long term operation by minimizing cathode potential drop over time.

  15. Collection and conversion of algal lipid

    NASA Astrophysics Data System (ADS)

    Lin, Ching-Chieh

    Sustainable economic activities mandate a significant replacement of fossil energy by renewable forms. Algae-derived biofuels are increasingly seen as an alternative source of energy with potential to supplement the world's ever increasing demand. Our primary objective is, once the algae were cultivated, to eliminate or make more efficient energy-intensive processing steps of collection, drying, grinding, and solvent extraction prior to conversion. To overcome the processing barrier, we propose to streamline from cultivated algae to biodiesel via algal biomass collection by sand filtration, cell rupturing with ozone, and immediate transesterification. To collect the algal biomass, the specific Chlorococcum aquaticum suspension was acidified to pH 3.3 to promote agglomeration prior to sand filtration. The algae-loaded filter bed was drained of free water and added with methanol and ozonated for 2 min to rupture cell membrane to accelerate release of the cellular contents. The methanol solution now containing the dissolved lipid product was collected by draining, while the filter bed was regenerated by further ozonation when needed. The results showed 95% collection of the algal biomass from the suspension and a 16% yield of lipid from the algae, as well as restoration of filtration velocity of the sand bed via ozonation. The results further showed increased lipid yield upon cell rupturing and transesterified products composed entirely of fatty acid methyl ester (FAME) compounds, demonstrating that the rupture and transesterification processes could proceed consecutively in the same medium, requiring no separate steps of drying, extraction, and conversion. The FAME products from algae without exposure to ozone were mainly of 16 to 18 carbons containing up to 3 double bonds, while those from algae having been ozonated were smaller, highly saturated hydrocarbons. The new technique streamlines individual steps from cultivated algal lipid to transesterified products and

  16. Live-cell imaging study of mitochondrial morphology in mammalian cells exposed to X-rays.

    PubMed

    Noguchi, M; Kanari, Y; Yokoya, A; Narita, A; Fujii, K

    2015-09-01

    Morphological changes in mitochondria induced by X-irradiation in normal murine mammary gland cells were studied with a live-cell microscopic imaging technique. Mitochondria were visualised by staining with a specific fluorescent probe in the cells, which express fluorescent ubiquitination-based cell-cycle indicator 2 (Fucci2) probes to visualise cell cycle. In unirradiated cells, the number of cells with fragmented mitochondria was about 20 % of the total cells through observation period (96 h). In irradiated cells, the population with fragmented mitochondria significantly increased depending on the absorbed dose. Particularly, for 8 Gy irradiation, the accumulation of fragmentation persists even in the cells whose cell cycle came to a stand (80 % in G1 (G0-like) phase). The fraction reached to a maximum at 96 h after irradiation. The kinetics of the fraction with fragmented mitochondria was similar to that for cells in S/G2/M phase (20 %) through the observation period (120 h). The evidences show that, in irradiated cells, some signals are continually released from a nucleus or cytoplasm even in the G0-like cells to operate some sort of protein machineries involved in mitochondrial fission. It is inferred that this delayed mitochondrial fragmentation is strongly related to their dysfunction, and hence might modulate radiobiological effects such as mutation or cell death.

  17. Regulation of gene expression in Dictyostelium discoideum cells exposed to immobilized carbohydrates

    PubMed Central

    Bozzaro, Salvatore; Perlo, Carla; Ceccarelli, Adriano; Mangiarotti, Giorgio

    1984-01-01

    When amoebae of Dictyostelium discoideum develop on gels of polyacrylamide that are derivatized with glucosides, they become capable of aggregation at the same time as cells not exposed to glucosides. However, the aggregation centers and streams of adherent cells formed on immobilized glucosides suddenly disintegrate. The cells repeatedly re-aggregate, but never form tight aggregates as they do on other substrata. Tight aggregates formed in the absence of glucosides disperse after their transfer to glucoside gels, and the cells undergo aggregation-disaggregation cycles. The formation of tight aggregates is correlated with the expression of specific post-aggregative poly(A)+ RNAs. These RNAs are not expressed in cells developing on glucoside gels, and the dispersal of tight aggregates on such gels is accompanied by the almost complete loss of these RNAs. A developmentally regulated membrane glycoprotein called contact site A, which is a marker of aggregation-competent cells, is normally expressed on glucoside gels. Cyclic AMP is also produced, indicating that the strong increase of adenylate cyclase activity during the preaggregation phase is not affected. In conclusion, cell contact with immobilized glucosides specifically inhibits postaggregative gene expression and arrests development at the aggregation stage. ImagesFig. 1.Fig. 2.Fig. 3.Fig. 5.Fig. 7. PMID:16453493

  18. Fate of D3 mouse embryonic stem cells exposed to X-rays or carbon ions.

    PubMed

    Luft, S; Pignalosa, D; Nasonova, E; Arrizabalaga, O; Helm, A; Durante, M; Ritter, S

    2014-01-15

    The risk of radiation exposure during embryonic development is still a major problem in radiotoxicology. In this study we investigated the response of the murine embryonic stem cell (mESC) line D3 to two radiation qualities: sparsely ionizing X-rays and densely ionizing carbon ions. We analyzed clonogenic cell survival, proliferation, induction of chromosome aberrations as well as the capability of cells to differentiate to beating cardiomyocytes up to 3 days after exposure. Our results show that, for all endpoints investigated, carbon ions are more effective than X-rays at the same radiation dose. Additionally, in long term studies (≥8 days post-irradiation) chromosomal damage and the pluripotency state were investigated. These studies reveal that pluripotency markers are present in the progeny of cells surviving the exposure to both radiation types. However, only in the progeny of X-ray exposed cells the aberration frequency was comparable to that of the control population, while the progeny of carbon ion irradiated cells harbored significantly more aberrations than the control, generally translocations. We conclude that cells surviving the radiation exposure maintain pluripotency but may carry stable chromosomal rearrangements after densely ionizing radiation.

  19. Regulation of gene expression in Dictyostelium discoideum cells exposed to immobilized carbohydrates.

    PubMed

    Bozzaro, S; Perlo, C; Ceccarelli, A; Mangiarotti, G

    1984-01-01

    When amoebae of Dictyostelium discoideum develop on gels of polyacrylamide that are derivatized with glucosides, they become capable of aggregation at the same time as cells not exposed to glucosides. However, the aggregation centers and streams of adherent cells formed on immobilized glucosides suddenly disintegrate. The cells repeatedly re-aggregate, but never form tight aggregates as they do on other substrata. Tight aggregates formed in the absence of glucosides disperse after their transfer to glucoside gels, and the cells undergo aggregation-disaggregation cycles. The formation of tight aggregates is correlated with the expression of specific post-aggregative poly(A) RNAs. These RNAs are not expressed in cells developing on glucoside gels, and the dispersal of tight aggregates on such gels is accompanied by the almost complete loss of these RNAs. A developmentally regulated membrane glycoprotein called contact site A, which is a marker of aggregation-competent cells, is normally expressed on glucoside gels. Cyclic AMP is also produced, indicating that the strong increase of adenylate cyclase activity during the preaggregation phase is not affected. In conclusion, cell contact with immobilized glucosides specifically inhibits postaggregative gene expression and arrests development at the aggregation stage.

  20. Chromosome Aberrations in Normal and Ataxia-Telangiectasia Cells Exposed to Heavy Ions

    NASA Technical Reports Server (NTRS)

    Kawata, T.; Ito, H.; Liu, C.; Shigematsu, N.; George, K.; Cucinotta, F. A.

    2007-01-01

    Although cells derived from Ataxia Telangiectasia (AT) patients are known to exhibit abnormal responses to ionizing radiations, its underlying mechanism still remains unclear. Previously, the authors reported that at the same gamma-irradiation dose AT cells show higher frequencies of misrepair and deletions compared to normal human fibroblast cells. In this study, we investigated the effects of heavy ions beams on chromosomal aberrations in normal and AT cells. Normal and AT fibroblast cells arrested at G0/G1 phase were irradiated with 2 Gy of X-rays, 490 MeV/u Silicon (LET 55 keV/m), 500 MeV/u Iron (LET 185 keV/m) and 200 MeV/u Iron (LET 440 keV/m) particles, and then cells were allowed to repair for 24 hours at 37 degrees before subculture. Calyculin-A induced PCC method was employed to collect G2/M chromosomes and whole DNA probes 1 and 3 were used to analyze chromosomal aberrations such as color-junctions, deletions, simple exchanges (incomplete and reciprocal exanges) and complex-type exchanges. The percentages of aberrant cells were higher when normal and AT cells were exposed to heavy ions compared to X-rays, and had a tendency to increase with increasing LET up to 185 keV/m and then decreased at 440 keV/m. When the frequency of color-junctions per cell was compared after X-ray exposure, AT cells had around three times higher frequency of color-junctions (mis-rejoining) than normal cells. However, at 185 keV/m there was no difference in the frequency of color-junctions between two cell lines. It was also found that the frequency of simple exchanges per cell was almost constant in AT cells regardless LET levels, but it was LET dependent for normal cells. Interestingly, the frequency of simple exchanges was higher for AT cells when it was compared at 185 keV/m but AT cells had more complex-type exchanges at the same LET levels. Heavy ions are more efficient in inducing chromosome aberrations in normal and AT cells compared to X-rays, and the aberration types

  1. Antioxidative capacity and enzyme activity in Haematococcus pluvialis cells exposed to superoxide free radicals

    NASA Astrophysics Data System (ADS)

    Liu, Jianguo; Zhang, Xiaoli; Sun, Yanhong; Lin, Wei

    2010-01-01

    The antioxidative capacity of astaxanthin and enzyme activity of reactive oxygen eliminating enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) were studied in three cell types of Haematococcus pluvialis exposed to high concentrations of a superoxide anion radical (O{2/-}). The results show that defensive enzymes and astaxanthin-related mechanisms were both active in H. pluvialis during exposure to reactive oxygen species (ROS) such as O{2/-}. Astaxanthin reacted with ROS much faster than did the protective enzymes, and had the strongest antioxidative capacity to protect against lipid peroxidation. The defensive mechanisms varied significantly between the three cell types and were related to the level of astaxanthin that had accumulated in those cells. Astaxanthin-enriched red cells had the strongest antioxidative capacity, followed by brown cells, and astaxanthin-deficient green cells. Although there was no significant increase in expression of protective enzymes, the malondialdehyde (MDA) content in red cells was sustained at a low level because of the antioxidative effect of astaxanthin, which quenched O{2/-} before the protective enzymes could act. In green cells, astaxanthin is very low or absent; therefore, scavenging of ROS is inevitably reliant on antioxidative enzymes. Accordingly, in green cells, these enzymes play the leading role in scavenging ROS, and the expression of these enzymes is rapidly increased to reduce excessive ROS. However, because ROS were constantly increased in this study, the enhance enzyme activity in the green cells was not able to repair the ROS damage, leading to elevated MDA content. Of the four defensive enzymes measured in astaxanthin-deficient green cells, SOD eliminates O{2/-}, POD eliminates H2O2, which is a by-product of SOD activity, and APX and CAT are then initiated to scavenge excessive ROS.

  2. Radiation-Induced Bystander Effects in A549 Cells Exposed to 6 MV X-rays.

    PubMed

    Yang, Shuning; Xu, Jing; Shao, Weixian; Geng, Chong; Li, Jia; Guo, Feng; Miao, Hui; Shen, Wenbin; Ye, Tao; Liu, Yazhou; Xu, Haiting; Zhang, Xuguang

    2015-07-01

    The aim of the study is to explore the bystander effects in A549 cells that have been exposed to 6MV X-ray. Control group, irradiated group, irradiated conditioned medium (ICM)-received group, and fresh medium group were designed in this study. A549 cells in the logarithmic growth phase were irradiated with 6MV X-ray at 0, 0.5, 1, 1.5, and 2. In ICM-received group, post-irradiation A549 cells were cultured for 3 h and were transferred into non-irradiated A549 cells for further cultivation. Clone forming test was applied to detect the survival fraction of cells. Annexin V-FITC/PI double-staining assay was used to detect the apoptosis of A549 cells 24, 48, 72, and 96 h after 2-Gy 6MV X-ray irradiation, and the curves of apoptosis were drawn. The changes in the cell cycles 4, 48, 72, and 96 h after 2-Gy 6MV X-ray irradiation were detected using PI staining flow cytometry. With the increase of irradiation dose, the survival fraction of A549 cells after the application of 0.5 Gy irradiation was decreasing continuously. In comparison to the control group, the apoptosis rate of the ICM-received group was increased in a time-dependent pattern, with the highest apoptosis rate observed at 72 h (p < 0.05). Cell count in G2/M stages was obviously increased compared with that of the control group (p < 0.05), with the highest count observed at 72 h, after which G2/M stage arrest was diminished. ICM can cause apparent A549 cell damage, indicating that 6MV X-ray irradiation can induce bystander effect on A549 cells, which reaches a peak at 72 h.

  3. Improving photosynthesis for algal biofuels: toward a green revolution.

    PubMed

    Stephenson, Patrick G; Moore, C Mark; Terry, Matthew J; Zubkov, Mikhail V; Bibby, Thomas S

    2011-12-01

    Biofuels derived from marine algae are a potential source of sustainable energy that can contribute to future global demands. The realisation of this potential will require manipulation of the fundamental biology of algal physiology to increase the efficiency with which solar energy is ultimately converted into usable biomass. This 'photosynthetic solar energy conversion efficiency' sets an upper limit on the potential of algal-derived biofuels. In this review, we outline photosynthetic molecular targets that could be manipulated to increase the efficiency and yield of algal biofuel production. We also highlight modern 'omic' and high-throughput technologies that might enable identification, selection and improvement of algal cell lines on timescales relevant for achieving significant contributions to future energy solutions.

  4. Algal Biofuels; Algal Biofuels R&D at NREL (Brochure)

    SciTech Connect

    Not Available

    2010-09-01

    An overview of NREL's algal biofuels projects, including U.S. Department of Energy-funded work, projects with U.S. and international partners, and Laboratory Directed Research and Development projects.

  5. Colon Stem Cell and Crypt Dynamics Exposed by Cell Lineage Reconstruction

    PubMed Central

    Itzkovitz, Shalev; Elbaz, Judith; Maruvka, Yosef E.; Segev, Elad; Shlush, Liran I.; Dekel, Nava; Shapiro, Ehud

    2011-01-01

    Stem cell dynamics in vivo are often being studied by lineage tracing methods. Our laboratory has previously developed a retrospective method for reconstructing cell lineage trees from somatic mutations accumulated in microsatellites. This method was applied here to explore different aspects of stem cell dynamics in the mouse colon without the use of stem cell markers. We first demonstrated the reliability of our method for the study of stem cells by confirming previously established facts, and then we addressed open questions. Our findings confirmed that colon crypts are monoclonal and that, throughout adulthood, the process of monoclonal conversion plays a major role in the maintenance of crypts. The absence of immortal strand mechanism in crypts stem cells was validated by the age-dependent accumulation of microsatellite mutations. In addition, we confirmed the positive correlation between physical and lineage proximity of crypts, by showing that the colon is separated into small domains that share a common ancestor. We gained new data demonstrating that colon epithelium is clustered separately from hematopoietic and other cell types, indicating that the colon is constituted of few progenitors and ruling out significant renewal of colonic epithelium from hematopoietic cells during adulthood. Overall, our study demonstrates the reliability of cell lineage reconstruction for the study of stem cell dynamics, and it further addresses open questions in colon stem cells. In addition, this method can be applied to study stem cell dynamics in other systems. PMID:21829376

  6. Proteome Analysis of Human Follicular Thyroid Cancer Cells Exposed to the Random Positioning Machine

    PubMed Central

    Bauer, Johann; Kopp, Sascha; Schlagberger, Elisabeth Maria; Grosse, Jirka; Sahana, Jayashree; Riwaldt, Stefan; Wehland, Markus; Luetzenberg, Ronald; Infanger, Manfred; Grimm, Daniela

    2017-01-01

    Several years ago, we detected the formation of multicellular spheroids in experiments with human thyroid cancer cells cultured on the Random Positioning Machine (RPM), a ground-based model to simulate microgravity by continuously changing the orientation of samples. Since then, we have studied cellular mechanisms triggering the cells to leave a monolayer and aggregate to spheroids. Our work focused on spheroid-related changes in gene expression patterns, in protein concentrations, and in factors secreted to the culture supernatant during the period when growth is altered. We detected that factors inducing angiogenesis, the composition of integrins, the density of the cell monolayer exposed to microgravity, the enhanced production of caveolin-1, and the nuclear factor kappa B p65 could play a role during spheroid formation in thyroid cancer cells. In this study, we performed a deep proteome analysis on FTC-133 thyroid cancer cells cultured under conditions designed to encourage or discourage spheroid formation. The experiments revealed more than 5900 proteins. Their evaluation confirmed and explained the observations mentioned above. In addition, we learned that FTC-133 cells growing in monolayers or in spheroids after RPM-exposure incorporate vinculin, paxillin, focal adhesion kinase 1, and adenine diphosphate (ADP)-ribosylation factor 6 in different ways into the focal adhesion complex. PMID:28273809

  7. The localization of DMPO spin adducts of OH in endothelial cells exposed to hydrogen peroxide.

    PubMed

    Kaneko, M; Kodama, M; Inoue, F

    1995-11-01

    Examination by electron spin resonance (ESR) spectroscopy revealed the localization of 5,5-dimethyl-l-pyrroline-N-oxide (DMPO) spin adducts of hydroxyl radicals (.OH) produced by bovine endothelial cells exposed to hydrogen peroxide. Addition of 10 mM chromium oxalate, a line-broadening agent, to the reaction mixture virtually abolished the signal of DMPO-OH spin adducts. Moreover, the spin adducts were recovered in the filtrated fraction of the cell suspension. We, therefore, concluded that the location of DMPO-OH due to .OH radicals produced by endothelial cells was extracellular. Contrastingly, the site of formation of DMPO-OH was confirmed to be intracellular by the effect of Desferal, an iron chelator, and the effect of poly(ethylene glycol), an extracellular scavenger of OH radicals, as previously reported. The DMPO-OH adducts in the cell suspension mixture were degraded by a cyanide sensitive pathway and they were apparently more unstable than in the extracellular fraction. The initial amount of DMPO-OH adducts formed in endothelial cells could potentially be monitored by the DMPO-OH signals in the extracellular reaction mixture better than those in the cell suspension mixture.

  8. Proteome Analysis of Human Follicular Thyroid Cancer Cells Exposed to the Random Positioning Machine.

    PubMed

    Bauer, Johann; Kopp, Sascha; Schlagberger, Elisabeth Maria; Grosse, Jirka; Sahana, Jayashree; Riwaldt, Stefan; Wehland, Markus; Luetzenberg, Ronald; Infanger, Manfred; Grimm, Daniela

    2017-03-03

    Several years ago, we detected the formation of multicellular spheroids in experiments with human thyroid cancer cells cultured on the Random Positioning Machine (RPM), a ground-based model to simulate microgravity by continuously changing the orientation of samples. Since then, we have studied cellular mechanisms triggering the cells to leave a monolayer and aggregate to spheroids. Our work focused on spheroid-related changes in gene expression patterns, in protein concentrations, and in factors secreted to the culture supernatant during the period when growth is altered. We detected that factors inducing angiogenesis, the composition of integrins, the density of the cell monolayer exposed to microgravity, the enhanced production of caveolin-1, and the nuclear factor kappa B p65 could play a role during spheroid formation in thyroid cancer cells. In this study, we performed a deep proteome analysis on FTC-133 thyroid cancer cells cultured under conditions designed to encourage or discourage spheroid formation. The experiments revealed more than 5900 proteins. Their evaluation confirmed and explained the observations mentioned above. In addition, we learned that FTC-133 cells growing in monolayers or in spheroids after RPM-exposure incorporate vinculin, paxillin, focal adhesion kinase 1, and adenine diphosphate (ADP)-ribosylation factor 6 in different ways into the focal adhesion complex.

  9. Transcriptional and Secretomic Profiling of Epidermal Cells Exposed to Alpha Particle Radiation

    PubMed Central

    Chauhan, Vinita; Howland, Matthew; Greene, Hillary Boulay; Wilkins, Ruth C

    2012-01-01

    Alpha (α)-particle emitters are probable isotopes to be used in a terrorist attack. The development of biological assessment tools to identify those who have handled these difficult to detect materials would be an asset to our current forensic capacity. In this study, for the purposes of biomarker discovery, human keratinocytes were exposed to α-particle and X-radiation (0.98 Gy/h at 0, 0.5, 1.0, 1.5 Gy) and assessed for differential gene and protein expression using microarray and Bio-Plex technology, respectively. Secretomic analysis of supernatants showed expression of two pro-inflammatory cytokines (IL-13 and PDGF-bb) to be exclusively affected in α-particle exposed cells. The highest dose of α-particle radiation modulated a total of 67 transcripts (fold change>|1.5|, (False discovery rate) FDR<0.05) in exposed cells. Several genes which responded with high expression levels (>2 fold) included KIF20A, NEFM, C7orf10, HIST1H2BD, BMP6, and HIST1H2AC. Among the high expressing genes, five (CCNB2, BUB1, NEK2, CDC20, AURKA) were also differentially expressed at the medium (1.0 Gy) dose however, these genes were unmodulated following exposure to X-irradiation. Networks of these genes clustered around tumor protein-53 and transforming growth factor-beta signaling. This study has identified some potential gene /protein responses and networks that may be validated further to confirm their specificity and potential to be signature biomarkers of α-particle exposure. PMID:23002402

  10. A case of epidermodysplasia verruciformis with squamous cell carcinomas on non-sun-exposed areas of skin.

    PubMed

    Ansarin, Habib; Tajziehchi, Leila; Shaianfar, Nasrin

    2007-04-01

    Epidermodysplasia verruciformis is an inherited disorder, characterized by multiple plane warts, pityriasis versicolor-like lesions, defects of cell-mediated immunity, and tendency to develop skin malignancies, primarily on sun-exposed areas. In this article, we present a case of epidermodysplasia verruciformis with multiple plane warts, pityriasis versicolor-like lesions, and squamous cell carcinomas on non-sun-exposed areas of skin. After acitretin prescription, significant improvement was found in plane warts, but not in pityriasis versicolor-like lesions.

  11. From the Cover: Exposing Imidacloprid Interferes With Neurogenesis Through Impacting on Chick Neural Tube Cell Survival.

    PubMed

    Liu, Meng; Wang, Guang; Zhang, Shi-Yao; Zhong, Shan; Qi, Guo-Long; Wang, Chao-Jie; Chuai, Manli; Lee, Kenneth Ka Ho; Lu, Da-Xiang; Yang, Xuesong

    2016-09-01

    As a neonicotinoid pesticide, imidacloprid is widely used to control insects in agriculture and fleas on domestic animals. However, it is not known whether imidacloprid exposure negatively affects neurogenesis during embryonic development. In this study, using a chick embryo model, we investigated the effects of imidacloprid exposure on neurogenesis at the earliest stage and during late-stage embryo development. Exposing HH0 chick embryos to imidacloprid in EC culture caused neural tube defects (NTDs) and neuronal differentiation dysplasia as determined by NF/Tuj1 labeling. Furthermore, we found that F-actin accumulation on the apical side of the neural tube was suppressed by exposure to imidacloprid, and the expression of BMP4 and Shh on the dorsal and ventral sides of the neural tubes, respectively, were also reduced, which in turn affects the dorsolateral hinge points during bending of the neural plate. In addition, exposure to imidacloprid reduced cell proliferation and increased cell apoptosis, as determined by pHIS3 labeling and TUNEL staining, respectively, also contributing to the malformation. We obtained similar results in late-stage embryos exposed to imidacloprid. Finally, a bioinformatics analysis was employed to determine which genes identified in this study were involved in NTDs. The experimental evidence and bioinformatics analysis suggested that imidacloprid exposure during chick embryo development could increase the risk of NTDs and neural dysplasia.

  12. Tumor necrosis factor alpha gene expression in human monocytic THP-1 cells exposed to beryllium.

    PubMed

    Galbraith, G M; Pandey, J P; Schmidt, M G; Arnaud, P; Goust, J M

    1996-01-01

    Chronic beryllium disease, which results from occupational exposure to particulate beryllium, is characterized by the development of lung granulomas and progressive pulmonary fibrosis. Increased production of proinflammatory cytokines (e.g., tumor necrosis factor alpha and interleukin-1 beta) by pulmonary alveolar macrophages occurs in many chronic fibrotic lung diseases and is thought to contribute to the disease process. The purpose of the present study was to investigate cytokine production by human monocytic cells exposed to beryllium in vitro. The results indicated that such cells respond to beryllium ions in the presence of fluoride by accumulation of messenger ribonucleic acid for both tumor necrosis factor alpha and interleukin-1 beta. These findings suggest that inhaled beryllium may directly stimulate the production of these cytokines by alveolar macrophages in vitro.

  13. Reduced cell viability and apoptosis induction in human thyroid carcinoma and mesothelioma cells exposed to cidofovir.

    PubMed

    Catalani, Simona; Palma, Francesco; Battistelli, Serafina; Nuvoli, Barbara; Galati, Rossella; Benedetti, Serena

    2017-02-20

    Besides its well-recognized antiviral activity, Cidofovir (CDV) has been shown to exert anticancer properties both within in vitro and in vivo models. The aim of this study was to evaluate the effects of CDV on still unexplored cultured cancer cells from human mesothelioma as well as breast, colon, liver, lung, prostate, and thyroid carcinomas. Overall, a dose- and time-dependent inhibition of cell viability was observed after CDV exposure. To clarify the mechanisms underlying CDV action, apoptotic cell death was investigated in two infected cell lines [Ist-Mes1 and Ist-Mes2 mesothelioma cells (SV40+)] and in two uninfected cell lines (NCI-H2425 mesothelioma cells and FTC-133 thyroid cancer cells), which resulted the most sensitive to CDV treatment. Reduced expression of procaspase-3 and increased expression of PARP p85 fragment were observed in both infected and uninfected mesothelioma cells, indicating apoptosis induction by CDV in a virus-independent manner. Similarly, the increase of the pro-apoptotic proteins p53, cytochrome c and caspase-3, the decrease of the survival protein Bcl-x, and the increment of Bax/Bcl-2 ratio revealed the occurrence of apoptosis in CDV-treated FTC-133. The presence of nuclear DNA fragmentation confirmed apoptotic cell death by CDV. Overall, our findings warrant further investigations to explore the therapeutic potential of CDV for human mesothelioma and follicular thyroid carcinoma.

  14. Gene expression profile of Jurkat cells exposed to high power terahertz radiation

    NASA Astrophysics Data System (ADS)

    Grundt, Jessica E.; Roth, Caleb C.; Rivest, Benjamin D.; Doroski, Michael L.; Payne, Jason; Ibey, Bennett L.; Wilmink, Gerald J.

    2011-03-01

    Terahertz (THz) radiation sources are now being used in a host of military, defense, and medical applications. Widespread employment of these applications has prompted concerns regarding the health effects associated with THz radiation. In this study, we examined the gene expression profile of mammalian cells exposed to THz radiation. We hypothesized that if THz radiation couples directly to cellular constituents, then exposed cells may express a specific gene expression profile indicative of ensuing damage. To test this hypothesis, Jurkat cells were irradiated with a molecular gas THz laser (2.52 THz, 636 mWcm-2, durations: 5, 10, 20, 30, 40, or 50 minutes). Viability was assessed 24 h post-exposure using MTT assays, and gene expression profiles were evaluated 4 h post-exposure using mRNA microarrays. Comparable analyses were also performed for hyperthermic positive controls (44°C for 40 minutes). We found that cellular temperatures increased by ~6 °C during THz exposures. We also found that cell death increased with exposure duration, and the median lethal dose (LD50) was calculated to be ~44 minutes. The microarray data showed that THz radiation induced the transcriptional activation of genes associated with cellular proliferation, differentiation, transcriptional activation, chaperone protein stabilization, and apoptosis. For most genes, we found that the magnitude of differential expression was comparable for both the THz and thermal exposure groups; however, several genes were specifically activated by the THz exposure. These results suggest that THz radiation may elicit effects that are not exclusively due to the temperature rise created during THz exposures (i.e. thermal effects). In future work, we plan to verify the results of our microarray experiments using qPCR techniques.

  15. Nasal cell micronuclei, cytology and clinical symptoms in stainless steel production workers exposed to chromium.

    PubMed

    Huvinen, Markku; Mäkitie, Antti; Järventaus, Hilkka; Wolff, Henrik; Stjernvall, Tuula; Hovi, Arja; Hirvonen, Ari; Ranta, Riikka; Nurminen, Markku; Norppa, Hannu

    2002-09-01

    The objective of the present study was to determine whether workers in stainless steel production with low exposure to various forms of chromium show an increase in micronucleated nasal cells or an excess of nasal symptoms or disease. Altogether, 48 workers employed in a stainless steel production chain were studied, 29 of them in the steel melting shop with exposure to hexavalent chromium (Cr(6+)), 14 in the sintering and crushing departments of the ferrochromium plant with exposure to trivalent chromium (Cr(3+)) and five in the mine with exposure to chromite ore (Cr(3+)). Thirty-nine workers from the cold rolling mill, with very low exposure to chromium, served as referents. All the subjects were never smokers with a minimum of 14 years employment in the same department. There were no significant differences between the exposure groups and the referents regarding the mean frequency of centromere-negative or centromere-positive micronuclei (studied by pancentromeric fluorescence in situ hybridization), nasal diseases and symptoms or mucociliary clearance of the nasal cavity. No statistically significant differences in the incidence of cell atypia or inflammatory cells were detected between the exposed workers and the reference group, except for an increase in lymphocytes among the chromite ore workers. Anterior rhinoscopy indicated slight inflammatory changes in nasal mucosa and secretion more often in the Cr(6+) and Cr(3+) groups than in the referents, the Cr(6+)-exposed workers showing more livid or oedemic epithelium. In conclusion, the stainless steel production workers, with low exposure to dusts or fumes containing hexavalent or trivalent chromium, did not show clinical changes in the nasal mucosa or an increase in nasal cell micronuclei or symptoms of nasal diseases, except for slight changes in the nasal epithelium and secretion.

  16. Altered gene expression in HepG2 cells exposed to a methanolic coal dust extract.

    PubMed

    Guerrero-Castilla, Angelica; Olivero-Verbel, Jesus

    2014-11-01

    Exposure to coal dust has been associated with different chronic diseases and mortality risk. This airborne pollutant is produced during coal mining and transport activities, generating environmental and human toxicity. The aim of this study was to determine the effects of a coal dust methanolic extract on HepG2, a human liver hepatocellular carcinoma cell line. Cells were exposed to 5-100ppm methanolic coal extract for 12h, using DMSO as control. MTT and comet assays were used for the evaluation of cytotoxicity and genotoxicity, respectively. Real time PCR was utilized to quantify relative expression of genes related to oxidative stress, xenobiotic metabolism and DNA damage. Coal extract concentrations did not induce significant changes in HepG2 cell viability after 12h exposure; however, 50 and 100ppm of the coal extract produced a significant increase in genetic damage index with respect to negative control. Compared to vehicle control, mRNA CYP1A1 (up to 163-fold), NQO1 (up to 4.7-fold), and GADD45B (up to 4.7-fold) were up regulated, whereas PRDX1, SOD, CAT, GPX1, XPA, ERCC1 and APEX1 remained unaltered. This expression profile suggests that cells exposed to coal dust extract shows aryl hydrocarbon receptor-mediated alterations, changes in cellular oxidative status, and genotoxic effects. These findings share some similarities with those observed in liver of mice captured near coal mining areas, and add evidence that living around these industrial operations may be negatively impacting the biota and human health.

  17. Detection of programmed cell death in cells exposed to genotoxic agents using a caspase activation assay.

    PubMed

    Gehring, Michael E; Koty, Patrick P

    2005-01-01

    Many environmental toxins cause DNA damage. Cells that have sustained significant DNA damage must attempt to repair the damage prior to replication, in which aberrant base incorporation can result in an irreversible mutation. If a cell cannot repair the damage, however, it may commit suicide through a genetically regulated programmed cell death (PCD) pathway. Crucial to the ultimate execution of PCD is a family of cysteine proteases called caspases. Activation of these enzymes occurs late in the PCD pathway, when a cell can no longer avoid cell death, but earlier than other PCD markers, such as morphological changes or DNA fragmentation. This protocol details a method for using fluorochrome-conjugated caspase inhibitors for the detection of activated caspases in intact cells using fluorescent microscopy.

  18. Effects of acidification on algal assemblages in temporary ponds

    SciTech Connect

    Glackin, M.E.; Pratt, J.R.

    1994-12-31

    Atmospheric deposition monitoring in Pennsylvania has characterized a steep gradient of acidic ion depositions across the north-central portion of the state. This study evaluated acidification effects on the composition of algal assemblages in temporary ponds in two forested areas exposed to atmospheric deposition that varied in degree of acidity. Artificial substrates were used to sample and compare the algal assemblages in the two areas. Colonized communities were also transplanted to lower pH ponds to observe changes in species composition. A laboratory microcosm experiment manipulating pH was conducted to reduce the variables that differed between the two areas. Fewer algal taxa were present in lower pH ponds, on colonized substrates after transplant to lower pH ponds, and in lower pH laboratory treatments. Species composition was altered in the lower pH conditions. Most taxa that were excluded from the lower pH ponds naturally also did not survive when experimentally introduced to those conditions. These results suggest that acidification of temporary ponds can alter the structure of algal communities. There is interest in a possible link between acid deposition and reports of worldwide declines in amphibian populations. Algae are an important food source for larval amphibians, such as the wood frog, which require temporary ponds to breed. Changes in algal species composition could potentially impact the temporary pond and forest ecosystem.

  19. Proteomic Analysis of Primary Human Airway Epithelial Cells Exposed to the Respiratory Toxicant Diacetyl.

    PubMed

    Foster, Matthew W; Gwinn, William M; Kelly, Francine L; Brass, David M; Valente, Ashlee M; Moseley, M Arthur; Thompson, J Will; Morgan, Daniel L; Palmer, Scott M

    2017-02-03

    Occupational exposures to the diketone flavoring agent, diacetyl, have been associated with bronchiolitis obliterans, a rare condition of airway fibrosis. Model studies in rodents have suggested that the airway epithelium is a major site of diacetyl toxicity, but the effects of diacetyl exposure upon the human airway epithelium are poorly characterized. Here we performed quantitative LC-MS/MS-based proteomics to study the effects of repeated diacetyl vapor exposures on 3D organotypic cultures of human primary tracheobronchial epithelial cells. Using a label-free approach, we quantified approximately 3400 proteins and 5700 phosphopeptides in cell lysates across four independent donors. Altered expression of proteins and phosphopeptides were suggestive of loss of cilia and increased squamous differentiation in diacetyl-exposed cells. These phenomena were confirmed by immunofluorescence staining of culture cross sections. Hyperphosphorylation and cross-linking of basal cell keratins were also observed in diacetyl-treated cells, and we used parallel reaction monitoring to confidently localize and quantify previously uncharacterized sites of phosphorylation in keratin 6. Collectively, these data identify numerous molecular changes in the epithelium that may be important to the pathogenesis of flavoring-induced bronchiolitis obliterans. More generally, this study highlights the utility of quantitative proteomics for the study of in vitro models of airway injury and disease.

  20. Genotoxic changes to rodent cells exposed in vitro to tungsten, nickel, cobalt and iron.

    PubMed

    Bardack, Stephanie; Dalgard, Clifton L; Kalinich, John F; Kasper, Christine E

    2014-03-10

    Tungsten-based materials have been proposed as replacements for depleted uranium in armor-penetrating munitions and for lead in small-arms ammunition. A recent report demonstrated that a military-grade composition of tungsten, nickel, and cobalt induced a highly-aggressive, metastatic rhabdomyosarcoma when implanted into the leg muscle of laboratory rats to simulate a shrapnel wound. The early genetic changes occurring in response to embedded metal fragments are not known. In this study, we utilized two cultured rodent myoblast cell lines, exposed to soluble tungsten alloys and the individual metals comprising the alloys, to study the genotoxic effects. By profiling cell transcriptomes using microarray, we found slight, yet distinct and unique, gene expression changes in rat myoblast cells after 24 h metal exposure, and several genes were identified that correlate with impending adverse consequences of ongoing exposure to weapons-grade tungsten alloy. These changes were not as apparent in the mouse myoblast cell line. This indicates a potential species difference in the cellular response to tungsten alloy, a hypothesis supported by current findings with in vivo model systems. Studies examining genotoxic-associated gene expression changes in cells from longer exposure times are warranted.

  1. Bacterial cells exposed to nanosecond pulsed electric fields show lethal and sublethal effects.

    PubMed

    Perni, S; Chalise, P R; Shama, G; Kong, M G

    2007-12-15

    Cell suspensions of Escherichia coli K12 and Salmonella typhimurium were exposed to electrical pulses of 32 ns duration at a field intensity of 100 kV/cm and a repetition rate of 30 pulses per second for a total of 300 s. Treated cells were plated onto Tryptone Soya Agar (TSA) and TSA supplemented with NaCl, and cell counts were monitored daily for 3 days. The concentrations of NaCl used were 3 and 4% (w/v) for E. coli and 4 and 5% (w/v) for S. typhimurium. Treatment under these conditions resulted in a 2 log(10) reduction for E. coli and approximately a single log(10) reduction for S. typhimurium. For both species of bacteria it was discovered that the surviving population was composed of only 1% of uninjured cells. Moreover, the proportion of sublethally injured cells increased more rapidly than the total recoverable population suggesting a process of injury accumulation culminating in death rather than an 'all or nothing' mechanism. Sublethal injury manifested itself in a proportion of the injured population of both species by an extended lag phase at longer treatment times. Finally, possible mechanisms by which nanosecond electric pulses inactivate bacteria are discussed.

  2. [An immunocytochemical study of the C-cell function of the thyroid in rats exposed on the Kosmos-2044 biosatellite].

    PubMed

    Loginov, V I

    1993-01-01

    Immunocytochemical analysis of thyroid gland C-cells of the rats exposed to a 14-day space flight revealed a decrease in the number of C-cells, volume of their nuclei and a declined percentage of active secretory C-cells, which point to a decline of calcitonin proactive and calcitonin secretory hypofunction of the thyroid C-cells system in flown rats. Tail suspension as a microgravity model caused similar changes in C-cells.

  3. Linking NE1545 gene expression with cell volume changes in Nitrosomonas europaea cells exposed to aromatic hydrocarbons.

    PubMed

    Radniecki, Tyler S; Gilroy, Caslin A; Semprini, Lewis

    2011-01-01

    Nitrosomonas europaea, a model ammonia oxidizing bacterium, was exposed to a wide variety of aromatic hydrocarbons in 3 h batch assays. The expression of NE1545, a phenol sentinel gene involved in fatty acid metabolism, was monitored via quantitative real-time polymerase chain reaction (qRT-PCR) and a Coulter Counter technique was used to monitor changes in cell volume. Decreases in cell volume and NE1545 gene expression correlated strongly with exposure to aromatic hydrocarbons that possessed a single polar group substitution (e.g. phenol and aniline). Aromatic hydrocarbons that contain no polar group substitutions (e.g. toluene) or multiple polar group substitutions (e.g. p-hydroquinone) caused negligible changes in NE1545 expression and cell volume. The oxidation of aromatic hydrocarbons by N. europaea from configurations without a single polar group to one with two polar groups (e.g. p-cresol oxidized to 4-hydroxybenzyl alcohol) and from configurations with no polar groups to one with a single polar group (e.g. ethylbenzene oxidized to 4-ethylphenol) greatly influenced NE1545 gene expression and observed changes in cell volume. Nitrification inhibition in N. europaea by the aromatic hydrocarbons was found to be completely reversible; however, the decreases in cell volume were not reversible suggesting a physical change in cell membrane composition. Ammonia monooxygenase blocking studies showed that the chemical exposure that was responsible for the cell volume decrease and up-regulation in gene expression and not the observed inhibition. N. europaea is the first bacterium shown to experience significant changes in cell volume when exposed to μM concentrations of aromatic hydrocarbons, three orders of magnitude lower than previous studies with other bacteria.

  4. Iron-dependent cell death of hepatocellular carcinoma cells exposed to sorafenib.

    PubMed

    Louandre, Christophe; Ezzoukhry, Zakaria; Godin, Corinne; Barbare, Jean-Claude; Mazière, Jean-Claude; Chauffert, Bruno; Galmiche, Antoine

    2013-10-01

    The multikinase inhibitor sorafenib is currently the treatment of reference for advanced hepatocellular carcinoma (HCC). In our report, we examined the cytotoxic effects of sorafenib on HCC cells. We report that the depletion of the intracellular iron stores achieved by using the iron chelator deferoxamine (DFX) strikingly protects HCC cells from the cytotoxic effects of sorafenib. The protective effect of the depletion of intracellular iron stores could not be explained by an interference with conventional forms of programmed cell death, such as apoptosis or autophagic cell death. We also found that DFX did not prevent sorafenib from reaching its intracellular target kinases. Instead, the depletion of intracellular iron stores prevented sorafenib from inducing oxidative stress in HCC cells. We examined the possibility that sorafenib might exert a cytotoxic effect that resembles ferroptosis, a form of cell death in which iron-dependent oxidative mechanisms play a pivotal role. In agreement with this possibility, we found that pharmacological inhibitors (ferrostatin-1) and genetic procedures (RNA interference against IREB-2) previously reported to modulate ferroptosis, readily block the cytotoxic effects of sorafenib in HCC cells. Collectively, our findings identify ferroptosis as an effective mechanism for the induction of cell death in HCC. Ferroptosis could potentially become a goal for the medical treatment of HCC, thus opening new avenues for the optimization of the use of sorafenib in these tumors.

  5. Exosomes are released by bystander cells exposed to radiation-induced biophoton signals: Reconciling the mechanisms mediating the bystander effect

    PubMed Central

    Fernandez-Palomo, Cristian; McNeill, Fiona E.; Seymour, Colin B.; Rainbow, Andrew J.; Mothersill, Carmel E.

    2017-01-01

    Objective The objective of our study was to explore a possible molecular mechanism by which ultraviolet (UV) biophotons could elicit bystander responses in reporter cells and resolve the problem of seemingly mutually exclusive mechanisms of a physical UV signal & a soluble factor-mediated bystander signal. Methods The human colon carcinoma cell line, HCT116 p53 +/+, was directly irradiated with 0.5 Gy tritium beta particles to induce ultraviolet biophoton emission. Bystander cells were not directly irradiated but were exposed to the emitted UV biophotons. Medium was subsequently harvested from UV-exposed bystander cells. The exosomes extracted from this medium were incubated with reporter cell populations. These reporter cells were then assayed for clonogenic survival and mitochondrial membrane potential with and without prior treatment of the exosomes with RNase. Results Clonogenic cell survival was significantly reduced in reporter cells incubated with exosomes extracted from cells exposed to secondarily-emitted UV. These exosomes also induced significant mitochondrial membrane depolarization in receiving reporter cells. Conversely, exosomes extracted from non-UV-exposed cells did not produce bystander effects in reporter cells. The treatment of exosomes with RNase prior to their incubation with reporter cells effectively abolished bystander effects in reporter cells and this suggests a role for RNA in mediating the bystander response elicited by UV biophotons and their produced exosomes. Conclusion This study supports a role for exosomes released from UV biophoton-exposed bystander cells in eliciting bystander responses and also indicates a reconciliation between the UV-mediated bystander effect and the bystander effect which has been suggested in the literature to be mediated by soluble factors. PMID:28278290

  6. PD-L2 induction on dendritic cells exposed to Mycobacterium avium downregulates BCG-specific T cell response.

    PubMed

    Mendoza-Coronel, Elizabeth; Camacho-Sandoval, Rosa; Bonifaz, Laura C; López-Vidal, Yolanda

    2011-01-01

    The exposure to certain species of Nontuberculous Mycobacteria (NTM) can modulate the immune response induced by Mycobacterium bovis BCG. Mycobacterium avium has been postulated as a weak inducer of dendritic cell (DC) maturation. However, how the DC exposure to M. avium could contribute to the modulation of a BCG-specific CD4+ T cell response and the molecules involved remain unknown. Here, we exposed bone marrow-derived DCs (BMDCs) to M. avium either prior to exposure to BCG or as a unique stimulus. We found that M. avium induces high expression of PD-L2 (B7-DC) in BMDCs. This was dependent on IL-10 production through the TLR2-p38 MAPK signaling pathway. Exposure to M. avium prior to BCG results in BMDCs that do not express co-stimulatory molecules and pro-inflammatory cytokines, while the expression of PD-L2 and IL-10 was maintained. BMDCs exposed to M. avium impaired the activation of BCG-specific T cells through the PD-1: PD-L interaction. This suggests that a M. avium-induced phenotype in DCs might be implicated in the induction of mechanisms of tolerance that could impact the T cell response induced by BCG vaccination.

  7. Algal productivity modeling: a step toward accurate assessments of full-scale algal cultivation.

    PubMed

    Béchet, Quentin; Chambonnière, Paul; Shilton, Andy; Guizard, Guillaume; Guieysse, Benoit

    2015-05-01

    A new biomass productivity model was parameterized for Chlorella vulgaris using short-term (<30 min) oxygen productivities from algal microcosms exposed to 6 light intensities (20-420 W/m(2)) and 6 temperatures (5-42 °C). The model was then validated against experimental biomass productivities recorded in bench-scale photobioreactors operated under 4 light intensities (30.6-74.3 W/m(2)) and 4 temperatures (10-30 °C), yielding an accuracy of ± 15% over 163 days of cultivation. This modeling approach addresses major challenges associated with the accurate prediction of algal productivity at full-scale. Firstly, while most prior modeling approaches have only considered the impact of light intensity on algal productivity, the model herein validated also accounts for the critical impact of temperature. Secondly, this study validates a theoretical approach to convert short-term oxygen productivities into long-term biomass productivities. Thirdly, the experimental methodology used has the practical advantage of only requiring one day of experimental work for complete model parameterization. The validation of this new modeling approach is therefore an important step for refining feasibility assessments of algae biotechnologies.

  8. Global gene expression profiling in human lung cells exposed to cobalt

    PubMed Central

    Malard, Veronique; Berenguer, Frederic; Prat, Odette; Ruat, Sylvie; Steinmetz, Gerard; Quemeneur, Eric

    2007-01-01

    Background It has been estimated that more than 1 million workers in the United States are exposed to cobalt. Occupational exposure to 59 Co occurs mainly via inhalation and leads to various lung diseases. Cobalt is classified by the IARC as a possible human carcinogen (group 2B). Although there is evidence for in vivo and in vitro toxicity, the mechanisms of cobalt-induced lung toxicity are not fully known. The purpose of this work was to identify potential signatures of acute cobalt exposure using a toxicogenomic approach. Data analysis focused on some cellular processes and protein targets that are thought to be relevant for carcinogenesis, transport and biomarker research. Results A time course transcriptome analysis was performed on A549 human pulmonary cells, leading to the identification of 85 genes which are repressed or induced in response to soluble 59 Co. A group of 29 of these genes, representing the main biological functions, was assessed by quantitative RT-PCR. The expression profiles of six of them were then tested by quantitative RT-PCR in a time-dependent manner and three modulations were confirmed by Western blotting. The 85 modulated genes include potential cobalt carriers (FBXL2, ZNT1, SLC12A5), tumor suppressors or transcription factors (MAZ, DLG1, MYC, AXL) and genes linked to the stress response (UBC, HSPCB, BNIP3L). We also identified nine genes coding for secreted proteins as candidates for biomarker research. Of those, TIMP2 was found to be down-regulated and this modulation was confirmed, in a dose-dependent manner, at protein level in the supernatant of exposed cells. Conclusion Most of these genes have never been described as related to cobalt stress and provide original hypotheses for further study of the effects of this metal ion on human lung epithelial cells. A putative biomarker of cobalt toxicity was identified. PMID:17553155

  9. Calcium dependent and independent cytokine synthesis by air pollution particle-exposed human bronchial epithelial cells

    SciTech Connect

    Sakamoto, Noriho; Hayashi, Shizu; Gosselink, John; Ishii, Hiroshi; Ishimatsu, Yuji; Mukae, Hiroshi; Hogg, James C.; Eeden, Stephan F. van

    2007-12-01

    Exposure to ambient air pollution particles with a diameter of < 10 {mu}m (PM{sub 10}) has been associated with increased cardiopulmonary morbidity and mortality. We have shown that human bronchial epithelial cells (HBECs) exposed to PM{sub 10} produce pro-inflammatory mediators that contribute to a local and systemic inflammatory response. Changes in intracellular calcium concentrations ([Ca{sup 2+}]{sub i}) have been demonstrated to regulate several functions of the airway epithelium including the production of pro-inflammatory mediators. The aim of the present study was to determine the nature and mechanism of calcium responses induced by PM{sub 10} in HBECs and its relationship to cytokine synthesis. Methods: Primary HBECs were exposed to urban air pollution particles (EHC-93) and [Ca{sup 2+}]{sub i} responses were measured using the fluoroprobe (Fura-2). Cytokine levels were measured at mRNA and protein levels using real-time PCR and ELISA. Results: PM{sub 10} increased [Ca{sup 2+}]{sub i} in a dose-dependent manner. This calcium response was reduced by blocking the influx of calcium into cells (i.e. calcium-free medium, NiCl{sub 2}, LaCl{sub 3}). PM{sub 10} also decreased the activity of calcium pumps. PM{sub 10} increased the production of IL-1{beta}, IL-8, GM-CSF and LIF. Preincubation with intracellular calcium chelator (BAPTA-AM) attenuated IL-1{beta} and IL-8 production, but not GM-CSF and LIF production. Conclusion: We conclude that exposure to PM{sub 10} induces an increase in cytosolic calcium and cytokine production in bronchial epithelial cells. Our results also suggest that PM{sub 10} induces the production of pro-inflammatory mediators via either intracellular calcium-dependent (IL-1{beta}, IL-8) or -independent (GM-CSF, LIF) pathways.

  10. Detection of surface algal blooms using the newly developed algorithm surface algal bloom index (SABI)

    NASA Astrophysics Data System (ADS)

    Alawadi, Fahad

    2010-10-01

    Quantifying ocean colour properties has evolved over the past two decades from being able to merely detect their biological activity to the ability to estimate chlorophyll concentration using optical satellite sensors like MODIS and MERIS. The production of chlorophyll spatial distribution maps is a good indicator of plankton biomass (primary production) and is useful for the tracing of oceanographic currents, jets and blooms, including harmful algal blooms (HABs). Depending on the type of HABs involved and the environmental conditions, if their concentration rises above a critical threshold, it can impact the flora and fauna of the aquatic habitat through the introduction of the so called "red tide" phenomenon. The estimation of chlorophyll concentration is derived from quantifying the spectral relationship between the blue and the green bands reflected from the water column. This spectral relationship is employed in the standard ocean colour chlorophyll-a (Chlor-a) product, but is incapable of detecting certain macro-algal species that float near to or at the water surface in the form of dense filaments or mats. The ability to accurately identify algal formations that sometimes appear as oil spill look-alikes in satellite imagery, contributes towards the reduction of false-positive incidents arising from oil spill monitoring operations. Such algal formations that occur in relatively high concentrations may experience, as in land vegetation, what is known as the "red-edge" effect. This phenomena occurs at the highest reflectance slope between the maximum absorption in the red due to the surrounding ocean water and the maximum reflectance in the infra-red due to the photosynthetic pigments present in the surface algae. A new algorithm termed the surface algal bloom index (SABI), has been proposed to delineate the spatial distributions of floating micro-algal species like for example cyanobacteria or exposed inter-tidal vegetation like seagrass. This algorithm was

  11. The protective effect of curcumin in Olfactory Ensheathing Cells exposed to hypoxia.

    PubMed

    Bonfanti, Roberta; Musumeci, Teresa; Russo, Cristina; Pellitteri, Rosalia

    2017-02-05

    Curcumin, a phytochemical component derived from the rhizomes of Curcuma longa, has shown a great variety of pharmacological activities, such as anti-inflammatory, anti-tumor, anti-depression and anti-oxidant activity. Therefore, in the last years it has been used as a therapeutic agent since it confers protection in different neurodegenerative diseases, cerebral ischemia and excitotoxicity. Olfactory Ensheathing Cells (OECs) are glial cells of the olfactory system. They are able to secrete several neurotrophic growth factors, promote axonal growth and support the remyelination of damaged axons. OEC transplantation has emerged as a possible experimental therapy to induce repair of spinal cord injury, even if the functional recovery is still limited. Since hypoxia is a secondary effect in spinal cord injury, this in vitro study investigates the protective effect of curcumin in OECs exposed to hypoxia. Primary OECs were obtained from neonatal rat olfactory bulbs and placed both in normal and hypoxic conditions. Furthermore, some cells were grown with basic Fibroblast Growth Factor (bFGF) and/or curcumin at different concentration and times. The results obtained through immunocytochemical procedures and MTT test show that curcumin stimulates cell viability in OECs grown in normal and hypoxic conditions. Furthermore, the synergistic effect of curcumin and bFGF is the most effective exerting protection on OECs. Since spinal cord injury is often accompanied by secondary insults, such as ischemia or hypoxia, our results suggest that curcumin in combination with bFGF might be considered a possible approach for restoration in injuries.

  12. Mycobacterium tuberculosis genome-wide screen exposes multiple CD8+ T cell epitopes

    PubMed Central

    Hammond, A S; Klein, M R; Corrah, T; Fox, A; Jaye, A; McAdam, K P; Brookes, R H

    2005-01-01

    Mounting evidence suggests human leucocyte antigen (HLA) class I-restricted CD8+ T cells play a role in protective immunity against tuberculosis yet relatively few epitopes specific for the causative organism, Mycobacterium tuberculosis, are reported. Here a total genome-wide screen of M. tuberculosis was used to identify putative HLA-B*3501 T cell epitopes. Of 479 predicted epitopes, 13 with the highest score were synthesized and used to restimulate lymphocytes from naturally exposed HLA-B*3501 healthy individuals in cultured and ex vivo enzyme-linked immunospot (ELISPOT) assays for interferon (IFN)-γ. All 13 peptides elicited a response that varied considerably between individuals. For three peptides CD8+ T cell lines were expanded and four of the 13 were recognized permissively through the HLA-B7 supertype family. Although further testing is required we show the genome-wide screen to be feasible for the identification of unknown mycobacterial antigens involved in immunity against natural infection. While the mechanisms of protective immunity against M. tuberculosis infection remain unclear, conventional class I-restricted CD8+ T cell responses appear to be widespread throughout the genome. PMID:15762882

  13. Expression of potentially lethal damage in Chinese hamster cells exposed to hematoporphyrin derivative photodynamic therapy.

    PubMed

    Gomer, C J; Rucker, N; Ferrario, A; Murphree, A L

    1986-07-01

    Experiments were performed to determine whether the expression and/or repair of potentially lethal damage could be observed in mammalian cells exposed to hemataporphyrin derivative (HPD) photodynamic therapy (PDT). Photodynamic therapy was combined with posttreatment protocols known to inhibit the repair of potentially lethal damage in cells treated with X-rays, ultraviolet radiation, or alkylating agents. Potentiation of lethal damage from photodynamic therapy was induced by hypothermia (4 degrees C) following short (1 h) or extended (16 h) HPD incubation conditions. Caffeine potentiated the lethal effects of PDT only when cells were incubated with HPD for extended time periods. However, 3-aminobenzamide had no effect on the cytotoxic actions of PDT following either short or extended HPD incubations. Recovery from potentially lethal damage expressed by posttreatment hypothermia was complete within 1 h, while recovery from potentially lethal damage expressed by posttreatment caffeine required time periods of up to 24 h. The lack of effect of 3-aminobenzamide on expression of potentially lethal damage following photodynamic therapy may be related to direct inhibition of adenosine diphosphoribose transferase by photodynamic therapy. These results indicate that the expression and repair of potentially lethal damage can be observed in cells treated with PDT and will vary as a function of porphyrin incubation conditions.

  14. Human epithelial cells exposed to functionalized multiwalled carbon nanotubes: interactions and cell surface modifications.

    PubMed

    Fanizza, C; Casciardi, S; Incoronato, F; Cavallo, D; Ursini, C L; Ciervo, A; Maiello, R; Fresegna, A M; Marcelloni, A M; Lega, D; Alvino, A; Baiguera, S

    2015-09-01

    With the expansion of the production and applications of multiwalled carbon nanotubes (MWCNTs) in several industrial and science branches, the potential adverse effects on human health have attracted attention. Numerous studies have been conducted to evaluate how chemical functionalization may affect MWCNT effects; however, controversial data have been reported, showing either increased or reduced toxicity. In particular, the impact of carboxylation on MWCNT cytotoxicity is far from being completely understood. The aim of this work was the evaluation of the modifications induced by carboxylated-MWCNTs (MWCNTs-COOH) on cell surface and the study of cell-MWCNT-COOH interactions by means of field emission scanning electron microscope (FESEM). Human pulmonary epithelial cells (A549) were incubated with MWCNTs-COOH for different exposure times and concentrations (10 μg/mL for 1, 2, 4 h; 5, 10, 20 μg/mL for 24 h). At short incubation time, MWCNTs-COOH were easily observed associated with plasma membrane and in contact with microvilli. After 24 h exposure, FESEM analysis revealed that MWCNTs-COOH induced evident changes in the cellular surface in comparison to control cells: treated cells showed blebs, holes and a depletion of the microvilli density in association with structure modifications, such as widening and/or lengthening. In particular, an increase of cells showing holes and microvilli structure alterations was observed at 20 μg/mL concentration. FESEM analysis showed nanotube agglomerates, of different sizes, entering into the cell with two different mechanisms: inward bending of the membrane followed by nanotube sinking, and nanotube internalization directly through holes. The observed morphological microvilli modifications, induced by MWCNTs-COOH, could affect epithelial functions, such as the control of surfactant production and secretion, leading to pathological conditions, such as alveolar proteinosis. More detailed studies will be, however, necessary to

  15. Cytogenetic analysis of nasal mucosa cells and lymphocytes from high-level long-term formaldehyde exposed workers and low-level short-term exposed waiters.

    PubMed

    Ye, Xiaolei; Yan, Wensheng; Xie, Hong; Zhao, Meiying; Ying, Chenjiang

    2005-12-07

    The evidence for genotoxic potential of formaldehyde (FA) in humans is insufficient and conflicting. We previously reported a higher frequency of micronuclei in nasal and oral exfoliative cells from students exposed to formaldehyde vapor for short-term. To further evaluate the genetic effects of long-term occupational exposure to FA and short-term exposure to FA of indoor sources, the frequencies of micronuclei (MN) in nasal mucosa cells, sister chromatid exchanges (SCEs) of peripheral lymphocytes, and the lymphocyte subsets were evaluated in 18 non-smoking workers (mean exposure duration was 8.6 years) in an FA factory and 16 non-smoking waiters exposed to FA for 12 weeks in a ballroom. A non-smoking student group without occupational exposure (n=23) to FA was used as control. The 8h time-weighted average (TWA) concentrations of formaldehyde was 0.985+/-0.286 mg/m3 with the ceiling exposure concentration of 1.694 mg/m3 in the workshop, and 0.107+/-0.067 mg/m3 in the ballroom (5 h TWA). Higher frequencies of micronuclei per thousand cells in nasal mucosa cells of workers versus control (2.70+/-1.50 versus 1.25+/-0.65, p<0.05) and higher frequency of SCEs in peripheral lymphocytes of workers group (8.24+/-0.89 versus 6.38+/-0.41, p<0.05) were observed. Increased frequency of micronuclei in nasal mucosa cells or SCE in peripheral lymphocytes was not found among waiters group. The results suggest that the genotoxic potential of high level FA exposure may have occupational risks in long-term exposure groups.

  16. Shift in FTIR spectrum patterns in methomyl-exposed rat spleen cells.

    PubMed

    Suramana, T; Sindhuphak, R; Dusitsin, N; Posayanonda, T; Sinhaseni, P

    2001-04-10

    Methomyl is a highly toxic carbamate insecticide which is widely used in many agricultural countries. We have applied the Fourier-transformed infrared (FTIR) spectroscopic method to study the toxicity of methomyl on cytoskeletal protein and the nucleic acid of rat spleen cells. Rats were given methomyl by gavage at 2, 6 and 8 mg/kg in single doses. Colchicine, a microtubule-disrupting agent, was given to rats at 2, 4, and 6 mg/kg in single doses and mitomycin C, an alkylating agent which acts as a DNA-cross-linking agent, was given by an intraperitoneal route to rats at 1 mg/kg. It was shown that the wavenumber of FTIR spectra at amide I and amide II in both methomyl- and colchicine-exposed rats shifted in dose response manner when compared with the control (P < 0.05). The amide I and II shifts in these regions have been proposed to be the result of an alpha-helix protein conformational change. Toxic doses of mitomycin C, a DNA-cross-linking agent, did not result in this pattern. Moreover, all exposed rats showed an increase in the absorbance ratios that were related to the vibrational mode of the phosphodiester group in nucleic acid (P < 0.05).

  17. Folic acid supplementation affects apoptosis and differentiation of embryonic neural stem cells exposed to high glucose.

    PubMed

    Jia, De-yong; Liu, Hui-juan; Wang, Fu-wu; Liu, Shang-ming; Ling, Eng-Ang; Liu, Kai; Hao, Ai-jun

    2008-07-25

    Folic acid (FA) supplementation has been shown to be extremely effective in reducing the occurrence of neural tube defects (NTDs), one of the most common birth defects associated with diabetic pregnancy. However, the antiteratogenic mechanism of FA in diabetes-induced NTDs is unclear. This study investigated the neuroprotective mechanism of FA in neural stem cells (NSCs) exposed to high glucose in vitro. The undifferentiated or differentiated NSCs were cultured in normal D-glucose concentration (NG) or high D-glucose concentration (HG) with or without FA. FA supplementation significantly decreased apoptosis induced by HG and lowered the expression of p53 in the nucleus of undifferentiated NSCs exposed to HG. Administration of FA in differentiated NSCs did not alter their precocious differentiation induced by HG. The increased mRNA expression levels of the basic helix-loop-helix factors including Neurog1, Neurog2, NeuroD2, Mash1, Id1, Id2, and Hes5 in the presence of HG were not significantly affected by FA. The present results provided a cellular mechanism by which FA supplementation may have a potential role in prevention of NTDs in diabetic pregnancies. On the other hand, FA increased the mRNA expression levels of the above transcription factors and accelerated the differentiation of NSCs in the NG medium, suggesting that it may adversely affect the normal differentiation of NSCs. Therefore, the timing and dose of FA would be critical factors in considering FA supplementation in normal maternal pregnancy.

  18. Enhanced histamine release from lung mast cells of guinea pigs exposed to sulfuric acid aerosols

    SciTech Connect

    Fujimaki, Hidekazu ); Katayama, Noboru; Wakamori, Kazuo )

    1992-06-01

    To clarify the relationship between air pollution and mast cell response, the effects of sulfuric acid aerosols on histamine release from lung mast cells of guinea pigs were investigated. Guinea pigs were exposed to 0.3, 1.0 and 3.2 mg/m{sup 3} sulfuric acid (H{sub 2}SO{sub 4}) aerosols or 4 ppm nitrogen dioxide (NO{sub 2}) for 2 and 4 weeks. After the exposure, lung mast cell suspensions were isolated by collagenase treatment and antigen- or A23187-induced histamine release was measured. Antigen-induced histamine release from mast cells was significantly enhanced by the exposure to 1.0 and 3.2 mg/m{sup 3} H{sub 2}SO{sub 4} for 2 weeks, but exposure to H{sub 2}SO{sub 4} for 4 weeks did not show the enhancement of antigen-induced histamine release. A23187-induced histamine release was significantly enhanced by the exposure to 1.0 mg/m{sup 3} H{sub 2}SO{sub 4} or 4 ppm NO{sub 2} for 2 weeks, but suppression of histamine release from lung mast cells stimulated with A23187 was observed by the exposure to 3.2 mg/m{sup 3} H{sub 2}So{sub 4} for 4 weeks. The exposure to 0.3 mg/m{sup 3} H{sub 2}So{sub 4} showed no changes in antigen- and A23187-induced histamine release. The combination of 1.0 mg/m{sup 3} H{sub 2}So{sub 4} with 4 ppm NO{sub 2} for 2 weeks resulted in no changes in antigen- and A23187-induced histamine release. These results suggested that functional properties of lung mast cells may be altered by a low concentration of H{sub 2}So{sub 4} aerosol exposure.

  19. The Bioeffects Resulting from Prokaryotic Cells and Yeast Being Exposed to an 18 GHz Electromagnetic Field

    PubMed Central

    Pham, Vy T. H.; Nguyen, Song Ha; Baulin, Vladimir; Croft, Rodney J.; Phillips, Brian; Crawford, Russell J.

    2016-01-01

    The mechanisms by which various biological effects are triggered by exposure to an electromagnetic field are not fully understood and have been the subject of debate. Here, the effects of exposing typical representatives of the major microbial taxa to an 18 GHz microwave electromagnetic field (EMF)were studied. It appeared that the EMF exposure induced cell permeabilisation in all of the bacteria and yeast studied, while the cells remained viable (94% throughout the exposure), independent of the differences in cell membrane fatty acid and phospholipid composition. The resulting cell permeabilisation was confirmed by detection of the uptake of propidium iodine and 23 nm fluorescent silica nanospheres using transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM). Upon EMF exposure, the bacterial cell membranes are believed to become permeable through quasi-endocytosis processes. The dosimetry analysis revealed that the EMF threshold level required to induce the uptake of the large (46 nm) nanopsheres was between three and six EMF doses, with a specific absorption rate (SAR) of 3 kW/kg and 5 kW/kg per exposure, respectively, depending on the bacterial taxa being studied. It is suggested that the taxonomic affiliation and lipid composition (e.g. the presence of phosphatidyl-glycerol and/or pentadecanoic fatty acid) may affect the extent of uptake of the large nanospheres (46 nm). Multiple 18 GHz EMF exposures over a one-hour period induced periodic anomalous increases in the cell growth behavior of two Staphylococcus aureus strains, namely ATCC 25923 and CIP 65.8T. PMID:27391488

  20. The Bioeffects Resulting from Prokaryotic Cells and Yeast Being Exposed to an 18 GHz Electromagnetic Field.

    PubMed

    Nguyen, The Hong Phong; Pham, Vy T H; Nguyen, Song Ha; Baulin, Vladimir; Croft, Rodney J; Phillips, Brian; Crawford, Russell J; Ivanova, Elena P

    2016-01-01

    The mechanisms by which various biological effects are triggered by exposure to an electromagnetic field are not fully understood and have been the subject of debate. Here, the effects of exposing typical representatives of the major microbial taxa to an 18 GHz microwave electromagnetic field (EMF)were studied. It appeared that the EMF exposure induced cell permeabilisation in all of the bacteria and yeast studied, while the cells remained viable (94% throughout the exposure), independent of the differences in cell membrane fatty acid and phospholipid composition. The resulting cell permeabilisation was confirmed by detection of the uptake of propidium iodine and 23 nm fluorescent silica nanospheres using transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM). Upon EMF exposure, the bacterial cell membranes are believed to become permeable through quasi-endocytosis processes. The dosimetry analysis revealed that the EMF threshold level required to induce the uptake of the large (46 nm) nanopsheres was between three and six EMF doses, with a specific absorption rate (SAR) of 3 kW/kg and 5 kW/kg per exposure, respectively, depending on the bacterial taxa being studied. It is suggested that the taxonomic affiliation and lipid composition (e.g. the presence of phosphatidyl-glycerol and/or pentadecanoic fatty acid) may affect the extent of uptake of the large nanospheres (46 nm). Multiple 18 GHz EMF exposures over a one-hour period induced periodic anomalous increases in the cell growth behavior of two Staphylococcus aureus strains, namely ATCC 25923 and CIP 65.8T.

  1. Mechanical algal disruption for efficient biodiesel extraction

    NASA Astrophysics Data System (ADS)

    Krehbiel, Joel David

    Biodiesel from algae provides several benefits over current biodiesel feedstocks, but the energy requirements of processing algae into a useable fuel are currently so high as to be prohibitive. One route to improving this is via disruption of the cells prior to lipid extraction, which can significantly increase energy recovery. Unfortunately, several obvious disruption techniques require more energy than can be gained. This dissertation examines the use of microbubbles to improve mechanical disruption of algal cells using experimental, theoretical, and computational methods. New laboratory experiments show that effective ultrasonic disruption of algae is achieved by adding microbubbles to an algal solution. The configuration studied flows the solution through a tube and insonifies a small section with a high-pressure ultrasound wave. Previous biomedical research has shown effective cell membrane damage on animal cells with similar methods, but the present research is the first to extend such study to algal cells. Results indicate that disruption increases with peak negative pressure between 1.90 and 3.07 MPa and with microbubble concentration up to 12.5 x 107 bubbles/ml. Energy estimates of this process suggest that it requires only one-fourth the currently most-efficient laboratory-scale disruption process. Estimates of the radius near each bubble that causes disruption (i.e. the disruption radius) suggest that it increases with peak negative pressure and is near 9--20 microm for all cases tested. It is anticipated that these procedures can be designed for better efficiency and efficacy, which will be facilitated by identifying the root mechanisms of the bubble-induced disruption. We therefore examine whether bubble expansion alone creates sufficient cell deformation for cell rupture. The spherically-symmetric Marmottant model for bubble dynamics allows estimation of the flow regime under experimental conditions. Bubble expansion is modeled as a point source of

  2. Proteomic analysis of cell wall in four pathogenic species of Candida exposed to oxidative stress.

    PubMed

    Ramírez-Quijas, Mayra Denisse; López-Romero, Everardo; Cuéllar-Cruz, Mayra

    2015-10-01

    In order for Candida species to adhere and colonize human host cells they must express cell wall proteins (CWP) and adapt to reactive oxygen species (ROS) generated by phagocytic cells of the human host during the respiratory burst. However, how these pathogens change the expression of CWP in response to oxidative stress (OSR) is not known. Here, fifteen moonlight-like CWP were identified that expressed differentially in four species of Candida after they were exposed to H2O2 or menadione (O2(-)). These proteins included: (i) glycolytic enzymes, such as glyceraldehyde-3-phosphate dehydrogenase (Gapdh), fructose-bisphosphate aldolase (Fba1), phosphoglycerate mutase (Gpm1), phosphoglycerate kinase (Pgk), pyruvate kinase (Pk) and enolase (Eno1); (ii) the heat shock proteins Ssb1 and Ssa2; (iii) OSR proteins such as peroxyredoxin (Tsa1), the stress protein Ddr48 (Ddr48) and glutathione reductase (Glr1); (iv) other metabolic enzymes such as ketol-acid reductoisomerase (Ilv5) and pyruvate decarboxylase (Pdc1); and (v) other proteins such as elongation factor 1-beta (Efb1) and the 14-3-3 protein homolog. RT-PCR revealed that transcription of the genes coding for some of the identified CWP are differentially regulated. To our knowledge this is the first report showing that moonlight-like CWP are the first line of defense of Candida against ROS, and that they are differentially regulated in each of these pathogens.

  3. Noise Removal with Maintained Spatial Resolution in Raman Images of Cells Exposed to Submicron Polystyrene Particles

    PubMed Central

    Ahlinder, Linnea; Wiklund Lindström, Susanne; Lejon, Christian; Geladi, Paul; Österlund, Lars

    2016-01-01

    The biodistribution of 300 nm polystyrene particles in A549 lung epithelial cells has been studied with confocal Raman spectroscopy. This is a label-free method in which particles and cells can be imaged without using dyes or fluorescent labels. The main drawback with Raman imaging is the comparatively low spatial resolution, which is aggravated in heterogeneous systems such as biological samples, which in addition often require long measurement times because of their weak Raman signal. Long measurement times may however induce laser-induced damage. In this study we use a super-resolution algorithm with Tikhonov regularization, intended to improve the image quality without demanding an increased number of collected pixels. Images of cells exposed to polystyrene particles have been acquired with two different step lengths, i.e., the distance between pixels, and compared to each other and to corresponding images treated with the super-resolution algorithm. It is shown that the resolution after application of super-resolution algorithms is not significantly improved compared to the theoretical limit for optical microscopy. However, to reduce noise and artefacts in the hyperspectral Raman images while maintaining the spatial resolution, we show that it is advantageous to use short mapping step lengths and super-resolution algorithms with appropriate regularization. The proposed methodology should be generally applicable for Raman imaging of biological samples and other photo-sensitive samples.

  4. The immunostatus of natural killer cells in people exposed to sulfur mustard.

    PubMed

    Ghotbi, Ladan; Hassan, Zuhair

    2002-06-01

    Sulfur mustard (2,2-dichloroethyl sulfide, SM) has been documented as an alkylating agent. It has been widely used as a chemical weapon during the last two decades. Despite extensive worldwide research, no effective therapy has yet been devised for the treatment of patients exposed to SM. A severe suppression of the immune system still remains as the major cause of opportunistic infections, septicemia and death in such patients. The aim of this study was to determine the possible effect of SM on natural killer (NK) cells in patients suffering from SM injuries. Patients were classified into three groups: mild, moderate and severe. Blood sample obtained from each patient was examined using flowcytometric technique. Results showed that the percentage of NK cells (CD45+/CD56+) is significantly lower in severe patients than that of the control group (P<0.05). It was also observed that the activity of NK cells (CD56+/CD25+) in severe alkylating group is noticeably higher compared with the control group (P<0.1).

  5. Alterations of protein profile in zebrafish liver cells exposed to methyl parathion: a membrane proteomics approach.

    PubMed

    Huang, Qingyu; Huang, He-Qing

    2012-03-01

    Methyl parathion (MP) is an extensively used organophosphorus pesticide, which has been associated with a wide spectrum of toxic effects on environmental organisms. The aim of this study is to investigate the alterations of membrane protein profiles in zebrafish liver (ZFL) cell line exposed to MP for 24 h using proteomic approaches. Two-dimensional gel electrophoresis revealed a total of 13 protein spots, whose expression levels were significantly altered by MP. These differential proteins were subjected to matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry analysis, and nine proteins were identified to be membrane proteins, among which seven were up-regulated, while two were down-regulated. In addition, the mRNA levels corresponding to these differential membrane proteins were further analyzed by quantitative real-time PCR. And the differential expression of arginase-2 was specially validated via Western blotting. Regarding the physiological functions, these proteins are involved in molecular chaperon, cytoskeleton system, cell metabolism, signal transduction, transport and hormone receptor respectively, suggesting the complexity of MP-mediated toxicity to ZFL cell. These data could provide useful insights for better understanding the hepatotoxic mechanisms of MP and develop novel protein biomarkers for effectively monitoring MP contamination level in aquatic environment.

  6. Changes in protein expression profiles in bovine endometrial epithelial cells exposed to E. coli LPS challenge.

    PubMed

    Piras, Cristian; Guo, Yongzhi; Soggiu, Alessio; Chanrot, Metasu; Greco, Viviana; Urbani, Andrea; Charpigny, Gilles; Bonizzi, Luigi; Roncada, Paola; Humblot, Patrice

    2017-01-31

    E. coli is one of the most frequently involved bacteria in uterine diseases. Lipopolysaccharide (LPS) is a component of the outer membrane of Gram-negative bacteria involved in pathogenic processes leading to post-partum metritis and endometritis in cattle. It also causes inflammation of the endometrium. The increase of cell proliferation by LPS is part of the inflammatory process. The aim of this study was to investigate possible changes in protein expression in relation to the proliferative response of bEECs after challenge with E. coli-LPS. In vitro culture of bEECs was performed from cow genital tracts collected at a slaughterhouse. In passage 5, bEECs from each of 9 cows (3 series of 3 cows) were exposed to 0, 8, and 16 μg ml(-1) LPS for 72 h. At time 0 and 72 h later, attached cells/living cells were counted and for each time and LPS dosage, cells were frozen for proteomic analyses. All samples from the 3 series were analyzed by 2-D gel electrophoresis coupled to MALDI-TOF/TOF mass spectrometry. The samples from the first series were subjected to shotgun nLC-MS/MS analysis. From the whole differential proteomics analysis, 38 proteins were differentially expressed (p < 0.05 to p < 0.001) following exposure to LPS. Among them, twenty-eight were found to be up-regulated in the LPS groups in comparison to control groups and ten were down-regulated. Differentially expressed proteins were associated with cell proliferation and apoptosis, transcription, destabilization of cell structure, oxidative stress, regulation of histones, allergy and general cell metabolism pathways. The de-regulations induced by LPS were consistent with the proliferative phenotype and indicated strong alterations of several cell functions. In addition, some of the differentially expressed proteins relates to pathways activated at the time of implantation. The specific changes induced through those signals may have negative consequences for the establishment of pregnancy.

  7. Evaluation of flow mixing in an ARID-HV algal raceway using statistics of temporal and spatial distribution of fluid particles

    SciTech Connect

    Xu, Ben; Li, Peiwen; Waller, Peter; Huesemann, Michael H.

    2015-02-27

    This paper analyzes and evaluates the flow mixing in an open channel algal raceway for biofuel production. The flow mixing governs the frequency of how algae cells are exposed to sunlight, due to the fluid movement between the surface and the bottom of the algal raceway, thereby affecting algal growth rate. In this work, we investigated the flow mixing performance in a table-sized model of the High Velocity Algae Raceway Integrated Design (ARID-HV). Various geometries of the raceway channels and dams were considered in both the CFD analysis and experimental flowvisualization. In the CFD simulation, the pathlines of fluid particleswere analyzed to obtain the distribution of the number of times that particles passed across a critical water depth, Dc, defined as a cycle count. In addition, the distribution of the time period fraction that the fluid particles stayed in the zones above and below Dc was recorded. Such information was used to evaluate the flow mixing in the raceway. The CFD evaluation of the flow mixing was validated using experimental flow visualization, which showed a good qualitative agreement with the numerical results. In conclusion, this CFD-based evaluation methodology is recommended for flow field optimization for open channel algal raceways, as well as for other engineering applications in which flow mixing is an important concern.

  8. Ergothioneine products derived by superoxide oxidation in endothelial cells exposed to high-glucose.

    PubMed

    Servillo, Luigi; D'Onofrio, Nunzia; Casale, Rosario; Cautela, Domenico; Giovane, Alfonso; Castaldo, Domenico; Balestrieri, Maria Luisa

    2017-03-12

    Ergothioneine (Egt), 2-mercapto-L-histidine betaine (ESH), is a dietary component acting as antioxidant and cytoprotectant. In vitro studies demonstrated that Egt, a powerful scavenger of hydroxyl radicals, superoxide anion, hypochlorous acid and peroxynitrite, protects vascular function against oxidative damages, thus preventing endothelial dysfunction. In order to delve the peculiar oxidative behavior of Egt, firstly identified in cell free-systems, experiments were designed to identify the Egt oxidation products when endothelial cells (EC) benefit of its protection against high-glucose (hGluc). HPLC-ESI-MS/MS analyses revealed a decrease in the intracellular GSH levels and an increase in the ophthalmic acid (OPH) levels during hGluc treatment. Interestingly, in the presence of Egt, the decrease of the GSH levels was lower than in cells treated with hGluc alone, and this effect was paralleled by lower OPH levels. Egt was also effective in reducing the cytotoxicity of H2O2 and paraquat (PQT), an inducer of superoxide anion production, showing a similar time-dependent pattern of GSH and OPH levels, although with peaks occurring at different times. Importantly, Egt oxidation generated not only hercynine (EH) but also the sulfonic acid derivative (ESO3H) whose amounts were dependent on the oxidative stress employed. Furthermore, cell-free experiments confirmed the formation of both EH and ESO3H when Egt was reacted with superoxide anion. In summary, these data, by identifying the EH and ESO3H formation in EC exposed to hGluc, highlight the cellular antioxidant properties of Egt, whose peculiar redox behavior makes it an attractive candidate for the prevention of oxidative stress-associated endothelial dysfunction during hyperglycemia.

  9. Antioxidant status and selected biochemical parameters of porcine ovarian granulosa cells exposed to lead in vitro.

    PubMed

    Capcarová, Marcela; Kolesárová, Adriana; Lukác, Norbert; Sirotkin, Alexander; Roychoudhury, Shubhadeep

    2009-12-01

    The objective of this study was to determine the activity of superoxide dismutase (SOD), total antioxidant status (TAS) and release of calcium, phosphorus, magnesium, sodium, potassium, total lipids, totals proteins, glucose, cholesterol and triglycerides by porcine ovarian granulosa cells cultured in vitro after lead acetate administration. The parameters were analyzed using semi-automated clinical chemistry analyzer Microlab 300, microprocessor-controlled analyzer EasyLite and spectrophotometer Genesys 10. Cells were cultured with lead acetate trihydrate [Pb(CH(3)COO)(2).3H(2)O] as follows: group Max (5 mg Pb(CH(3)COO)(2).3H(2)O/10 mL), group A (2.5 mg/10 mL), group B (0.83 mg/10 mL), group C (0.625 mg/10 mL), group D (0.455 mg/10 mL) and the control group without lead exposure for 18 hrs. The highest TAS was estimated in the control group without lead treatment in comparison with other groups (MAX, A, B, C, D). Statistical analyses showed significantly lower value (P < 0.05) in group B. The activity of SOD was the lowest in the control group in comparison to those exposed to in vitro lead culture. A significant decrease (P < 0.05) of calcium content in group MAX in comparison with control group was determined. Release of phosphorus by ovarian granulosa cells was significantly lower (P < 0.05; 0.01; 0.001) in all the treated groups in comparison with control group. Lead was found to stimulate the release of magnesium and potassium by granulosa cells, but the increase remained statistically insignificant. The highest concentration of glucose was noted in control group, but the differences were not significant either. No significant differences (P > 0.05) were detected in concentration of other studied parameters among observed groups, too.

  10. Genetic polymorphisms and surface expression of CTLA-4 and PD-1 on T cells of silica-exposed workers.

    PubMed

    Rocha, Michelle C; Santos, Leonilda M B; Bagatin, Ericson; Cohen Tervaert, Jan W; Damoiseaux, Jan G M C; Lido, Alessandro V; Longhini, Ana L; Torello, Cristiane O; Queiroz, Mary L S

    2012-11-01

    Exposure to silica dust has been examined as a possible risk factor for autoimmune diseases, including scleroderma, rheumatoid arthritis and systemic lupus erythematosus. Since CTLA-4 [CD152] and PD-1 [CD279] are important for the maintenance of peripheral tolerance by regulating T cell responsiveness, we evaluated the expression of these molecules on the surface of CD4 and CD8 T cells, as well as single nucleotide polymorphisms (SNP) in CTLA-4 and PDCD1 genes, of 70 silica-exposed workers and 30 non-exposed, age-, ethnically- and sex-matched controls. Expression of CTLA-4 was significantly (P<0.05) reduced in CD4 T cells of exposed individuals [median=0.1% and interquartile range, IQR 0.0-0.1% (exposed), median=0.20%, IQR 0.0-0.4% (control)]. Also the expression of PD-1 was significantly (P<0.0001) reduced in both CD4 [median=0.9%, IQR 0.4-2.3% (exposed), median=5.7%, IQR 1.4-13.3% (control)] and CD8 T cells [median=0.9%, IQR 0.3-1.9% (exposed), median=5.0%, IQR 3.4-8.9% (control)]. The study of polymorphisms demonstrated a lower frequency of the A allele in the analysis of the PD1.3 SNP in the exposed group, which might be associated with the lower expression of PD-1 on the surface of CD4 T cells. Our findings provide evidence for the association of silica exposure and the maintenance of self-tolerance, i.e., the susceptibility to autoimmune disorders.

  11. Algal culture studies related to a Closed Ecological Life Support System (CELSS)

    NASA Technical Reports Server (NTRS)

    Radmer, R. O.; Ollinger, O.; Venables, A.; Fernandez, E.

    1982-01-01

    Studies with algal cultures which relate to closed ecological life support systems (CELSS) are discussed. A description of a constant cell density apparatus for continuous culture of algae is included. Excretion of algal by-products, and nitrogen utilization and excretion are discussed.

  12. Profiling transcriptomes of human SH-SY5Y neuroblastoma cells exposed to maleic acid

    PubMed Central

    Wang, Chia-Chi; Lin, Yin-Chi; Cheng, Yin-Hua

    2017-01-01

    Background Maleic acid is a multi-functional chemical widely used in the field of industrial chemistry for producing food additives and food contact materials. As maleic acid may contaminate food by the release from food packages or intentional addition, it raises the concern about the effects of excessive dietary exposure to maleic acid on human health. However, the influence of maleic acid on human health has not been thoroughly studied. In silico toxicogenomics approaches have found the association between maleic acid and nervous system disease in human. The aim of this study is to experimentally explore the effects of maleic acid on human neuronal cells. Methods A microarray-based transcriptome profiling was performed to offer a better understanding of the effects of maleic acid on human health. Gene expression profiles of human neuroblastoma SH-SY5Y cells exposed to three concentrations of maleic acid (10, 50, and 100 μM) for 24 h were analyzed. Genes which were differentially expressed in dose-dependent manners were identified and further analyzed with an enrichment analysis. The expression profile of selected genes related to the inferred functional changes was validated using quantitative polymerase chain reaction (qPCR). Specific fluorescence probes were applied to observe the inferred functional changes in maleic acid-treated neuronal cells. Results A total of 316 differentially expressed genes (141 upregulated and 175 downregulated) were identified in response to the treatment of maleic acid. The enrichment analysis showed that DNA binding and metal ion binding were the significant molecular functions (MFs) of the neuronal cells affected by maleic acid. Maleic acid exposure decreased the expression of genes associated with calcium and thiol levels of the cells in a dose-dependent manner. The levels of intracellular calcium and thiol levels were also affected by maleic acid dose-dependent. Discussion The exposure to maleic acid is found to decrease the

  13. Novel leukocyte agonists are released by endothelial cells exposed to peroxide.

    PubMed

    Patel, K D; Zimmerman, G A; Prescott, S M; McIntyre, T M

    1992-07-25

    Reactive oxygen species do not activate isolated neutrophils, yet in vivo, such oxidants promote their adhesion to, and subsequent migration through, the vascular wall. We show human endothelial cells exposed to t-butylhydroperoxide shed large, sealed membrane vesicles that contained potent neutrophil agonists. This activity migrated on TLC like platelet-activating factor (PAF). Since neutrophils have a receptor for this phospholipid, which recognizes its unique characteristics including the short sn-2 acetyl residue, we examined the effect of PAF receptor antagonists and PAF acetylhydrolase on this activity. Structurally unrelated PAF receptor antagonists blocked neutrophil stimulation by vesicular phospholipids, and digestion with PAF acetylhydrolase, which is specific for short sn-2 residues, destroyed this activity. However, metabolic labeling, inhibition of synthesis, phospholipase A1 digestion, and high performance liquid chromatographic studies demonstrated that the vesicles did not contain PAF. Instead, the bioactivity migrated on high performance liquid chromatography like the phospholipids generated by oxidative fragmentation of synthetic arachidonoyl phosphatidylcholine that we have shown previously (Smiley, P. L., Stremler, K. E., Prescott, S. M., Zimmerman, G. A., and McIntyre, T. M. (1991) J. Biol. Chem. 266, 11104-11110) to stimulate neutrophils through their receptor for PAF. Thus, peroxide treatment of endothelial cells fragments cellular phosphatidylcholines, forming novel PAF-like phospholipids, and induces the shedding of membrane vesicles that contain these bioactive phospholipids.

  14. Early alterations on photosynthesis-related parameters in Chlamydomonas reinhardtii cells exposed to atrazine: A multiple approach study.

    PubMed

    Esperanza, Marta; Seoane, Marta; Rioboo, Carmen; Herrero, Concepción; Cid, Ángeles

    2016-06-01

    Chlamydomonas reinhardtii cells were exposed to a sublethal concentration of the widespread herbicide atrazine for 3h. Physiological cellular parameters, such as chlorophyll a fluorescence and oxidative stress monitored by flow cytometry and pigments levels were altered in microalgal cells exposed to 0.25 μM of atrazine. Furthermore, the effects of this herbicide on C. reinhardtii were explored using "omics" techniques. Transcriptomic analyses, carried out by RNA-Seq technique, displayed 9 differentially expressed genes, related to photosynthesis, between control cultures and atrazine exposed cultures. Proteomic profiles were obtained using iTRAQ tags and MALDI-MS/MS analysis, identifying important changes in the proteome during atrazine stress; 5 proteins related to photosynthesis were downexpressed. The results of these experiments advance the understanding of photosynthetic adjustments that occur during an early herbicide exposure. Inhibition of photosynthesis induced by atrazine toxicity will affect the entire physiological and biochemical states of microalgal cells.

  15. Threshold radiant exposure for cell death in the endothelium of porcine cornea exposed to ultrashort laser pulses

    NASA Astrophysics Data System (ADS)

    Hussain, S. A.; Kowalczuk, L.; Crotti, C.; Alahyane, F.; Plamann, K.

    2013-06-01

    We have determined the threshold radiant exposure for cell death in the endothelium of porcine cornea exposed to ultrashort laser pulses in the context of keratoplasty and the preparation of endothelial grafts. In this study, by progressively increasing the radiant threshold towards the higher values we have observed a decrease of living corneal endothelial cells. Further study will address the effect of dose and possible mechanism behind cell death.

  16. Sapphire Energy - Integrated Algal Biorefinery

    SciTech Connect

    White, Rebecca L.; Tyler, Mike

    2015-07-22

    Sapphire Energy, Inc. (SEI) is a leader in large-scale photosynthetic algal biomass production, with a strongly cohesive research, development, and operations program. SEI takes a multidiscipline approach to integrate lab-based strain selection, cultivation and harvest and production scale, and extraction for the production of Green Crude oil, a drop in replacement for traditional crude oil.. SEI’s technical accomplishments since 2007 have produced a multifunctional platform that can address needs for fuel, feed, and other higher value products. Figure 1 outlines SEI’s commercialization process, including Green Crude production and refinement to drop in fuel replacements. The large scale algal biomass production facility, the SEI Integrated Algal Biorefinery (IABR), was built in Luna County near Columbus, New Mexico (see fig 2). The extraction unit was located at the existing SEI facility in Las Cruces, New Mexico, approximately 95 miles from the IABR. The IABR facility was constructed on time and on budget, and the extraction unit expansion to accommodate the biomass output from the IABR was completed in October 2012. The IABR facility uses open pond cultivation with a proprietary harvesting method to produce algal biomass; this biomass is then shipped to the extraction facility for conversion to Green Crude. The operation of the IABR and the extraction facilities has demonstrated the critical integration of traditional agricultural techniques with algae cultivation knowledge for algal biomass production, and the successful conversion of the biomass to Green Crude. All primary unit operations are de-risked, and at a scale suitable for process demonstration. The results are stable, reliable, and long-term cultivation of strains for year round algal biomass production. From June 2012 to November 2014, the IABR and extraction facilities produced 524 metric tons (MT) of biomass (on a dry weight basis), and 2,587 gallons of Green Crude. Additionally, the IABR

  17. Oxidative stress response in neural stem cells exposed to different superparamagnetic iron oxide nanoparticles

    PubMed Central

    Pongrac, Igor M; Pavičić, Ivan; Milić, Mirta; Brkić Ahmed, Lada; Babič, Michal; Horák, Daniel; Vinković Vrček, Ivana; Gajović, Srećko

    2016-01-01

    Biocompatibility, safety, and risk assessments of superparamagnetic iron oxide nanoparticles (SPIONs) are of the highest priority in researching their application in biomedicine. One improvement in the biological properties of SPIONs may be achieved by different functionalization and surface modifications. This study aims to investigate how a different surface functionalization of SPIONs – uncoated, coated with d-mannose, or coated with poly-l-lysine – affects biocompatibility. We sought to investigate murine neural stem cells (NSCs) as important model system for regenerative medicine. To reveal the possible mechanism of toxicity of SPIONs on NSCs, levels of reactive oxygen species, intracellular glutathione, mitochondrial membrane potential, cell-membrane potential, DNA damage, and activities of SOD and GPx were examined. Even in cases where reactive oxygen species levels were significantly lowered in NSCs exposed to SPIONs, we found depleted intracellular glutathione levels, altered activities of SOD and GPx, hyperpolarization of the mitochondrial membrane, dissipated cell-membrane potential, and increased DNA damage, irrespective of the surface coating applied for SPION stabilization. Although surface coating should prevent the toxic effects of SPIONs, our results showed that all of the tested SPION types affected the NSCs similarly, indicating that mitochondrial homeostasis is their major cellular target. Despite the claimed biomedical benefits of SPIONs, the refined determination of their effects on various cellular functions presented in this work highlights the need for further safety evaluations. This investigation helps to fill the knowledge gaps on the criteria that should be considered in evaluating the biocompatibility and safety of novel nanoparticles. PMID:27217748

  18. Distribution of Chromosome Breakpoints in Human Epithelial Cells Exposed to Low- and High-LET Radiations

    NASA Technical Reports Server (NTRS)

    Hada, Megumi; Cucinotta, Francis; Wu, Honglu

    2009-01-01

    The advantage of the multicolor banding in situ hybridization (mBAND) technique is not only its ability to identify simultaneously both inter- and intrachromosome exchanges, but also the ability to measure the breakpoint location along the length of the chromosome in a precision that is unmatched with other traditional banding techniques. Breakpoints on specific regions of a chromosome have been known to associate with specific cancers. The breakpoint distribution in cells after low- and high-LET radiation exposures will also provide the data for biophysical modeling of the chromatin structure, as well as the data for the modeling the formation of radiation-induced chromosome aberrations. In a series of experiments, we studied low- and high-LET radiation-induced chromosome aberrations using the mBAND technique with chromosome 3 painted in 23 different colored bands. Human epithelial cells (CH1 84B5F5/M10) were exposed in vitro to Cs- 137 rays at both low and high dose rates, secondary neutrons with a broad energy spectrum at a low dose rate and 600 MeV/u Fe ions at a high dose rate. The data of both inter- and intrachromosome aberrations involving the painted chromosome have been reported previously. Here we present data of the location of the chromosome breaks along the length of chromosome 3 in the cells after exposures to each of the four radiation scenarios. In comparison to the expected breakpoint distribution based on the length of the bands, the observed distribution appeared to be non-random for both the low- and high-LET radiations. In particular, hot spots towards both ends of the chromosome were found after low-LET irradiations of either low or high dose rates. For both high-LET radiation types (Fe ions and neutrons), the breakpoint distributions were similar, and were much smoother than that for low-LET radiation. The dependence of the breakpoint distribution on the radiation quality requires further investigations.

  19. DNA methylation analysis using CpG microarrays is impaired in benzopyrene exposed cells

    SciTech Connect

    Sadikovic, Bekim; Andrews, Joseph; Rodenhiser, David I.

    2007-12-15

    Epigenetic alterations have emerged as a key mechanism involved in tumorigenesis. These disruptions are partly due to environmental factors that change normal DNA methylation patterns necessary for transcriptional regulation and chromatin compaction. Microarray technologies are allowing environmentally susceptible epigenetic patterns to be mapped and the precise targets of environmentally induced alterations to be identified. Previously, we observed BaP-induced epigenetic events and cell cycle disruptions in breast cancer cell lines that included time- and concentration-dependent loss of proliferation as well as sequence-specific hypo- and hypermethylation events. In this present report, we further characterized epigenetic changes in BaP-exposed MCF-7 cells. We analyzed DNA methylation on a CpG island microarray platform with over 5400 unique genomic regions. Depleted and enriched microarray targets, representative of putative DNA methylation changes, were identified across the genome; however, subsequent sodium bisulfite analyses revealed no changes in DNA methylation at a number of these loci. Instead, we found that the identification of DNA methylation changes using this restriction enzyme-based microarray approach corresponded with the regions of DNA bound by the BaP derived DNA adducts. This DNA adduct formation occurs at both methylated and unmethylated CpG dinucleotides and affects PCR amplification during sample preparation. Our data suggest that caution should be exercised when interpreting data from comparative microarray experiments that rely on enzymatic reactions. These results are relevant to genome screening approaches involving environmental exposures in which DNA adduct formation at specific nucleotide sites may bias target acquisition and compromise the correct identification of epigenetically responsive genes.

  20. Proteomic responses of human intestinal Caco-2 cells exposed to silver nanoparticles and ionic silver.

    PubMed

    Oberemm, Axel; Hansen, Ulf; Böhmert, Linda; Meckert, Christine; Braeuning, Albert; Thünemann, Andreas F; Lampen, Alfonso

    2016-03-01

    Even although quite a number of studies have been performed so far to demonstrate nanoparticle-specific effects of substances in living systems, clear evidence of these effects is still under debate. The present study was designed as a comparative proteomic analysis of human intestinal cells exposed to a commercial silver nanoparticle reference material and ions from AgNO3. A two-dimensional gel electrophoresis/MALDI mass spectrometry (MS)-based proteomic analysis was conducted after 24-h incubation of differentiated Caco-2 cells with non-cytotoxic and low cytotoxic silver concentrations (2.5 and 25 µg ml(-1) nanosilver, 0.5 and 5 µg ml(-1) AgNO3). Out of an overall number of 316 protein spots differentially expressed at a fold change of ≥ 1.4 or ≤ -1.4 in all treatments, 169 proteins could be identified. In total, 231 spots were specifically deregulated in particle-treated groups compared with 41 spots, which were limited to AgNO3-treatments. Forty-four spots (14 %) were commonly deregulated by both types of treatment. A considerable fraction of the proteins differentially expressed after treatment with nanoparticles is related to protein folding, synthesis or modification of proteins as well as cellular assembly and organization. Overlays of networks obtained for particulate and ionic treatments showed matches, indicating common mechanisms of combined particle and ionic silver exposure and exclusive ionic silver treatment. However, proteomic responses of Caco-2 cells treated with higher concentrations of silver species also showed some differences, for example regarding proteins related to fatty acid and energy metabolism, suggesting an induction of also some different molecular mechanisms for particle exposure and ionic treatment.

  1. Proliferation assay of mouse embryonic stem (ES) cells exposed to atmospheric-pressure plasmas at room temperature

    NASA Astrophysics Data System (ADS)

    Miura, Taichi; Ando, Ayumi; Hirano, Kazumi; Ogura, Chika; Kanazawa, Tatsuya; Ikeguchi, Masamichi; Seki, Atsushi; Nishihara, Shoko; Hamaguchi, Satoshi

    2014-11-01

    Proliferation assays of mouse embryonic stem (ES) cells have been performed with cell culture media exposed to atmospheric-pressure plasmas (APPs), which generate reactive species in the media at room temperature. It is found that serum in cell culture media functions as a scavenger of highly reactive species and tends to protect cells in the media against cellular damage. On the other hand, if serum is not present in a cell culture medium when it is exposed to APP, the medium becomes cytotoxic and cannot be detoxified by serum added afterwards. Plasma-induced cytotoxic media hinder proliferation of mouse ES cells and may even cause cell death. It is also shown by nuclear magnetic resonance spectroscopy that organic compounds in cell culture media are in general not significantly modified by plasma exposure. These results indicate that if there is no serum in media when they are exposed to APPs, highly reactive species (such as OH radicals) generated in the media by the APP exposure are immediately converted to less reactive species (such as H2O2), which can no longer readily react with serum that is added to the medium after plasma exposure. This study has clearly shown that it is these less reactive species, rather than highly reactive species, that make the medium cytotoxic to mouse ES cells.

  2. Algal taxonomy forum: Algal Taxonomist, Let Serendipity Reign!

    PubMed

    Druehl, Louis

    2013-04-01

    The publication of a mini-review by Olivier De Clerck et al. in this issue of the Journal of Phycology presented an opportunity to open a dialogue on challenges faced by contemporary algal taxonomists. The Editorial Office solicited the following two additional contributions in response to De Clerck et al.'s paper; the responses were edited solely for clarity, space and format.

  3. Scan-Free Absorbance Spectral Imaging A(x, y, λ) of Single Live Algal Cells for Quantifying Absorbance of Cell Suspensions.

    PubMed

    Isono, Takumi; Yamashita, Kyohei; Momose, Daisuke; Kobayashi, Hiroki; Kitamura, Masashi; Nishiyama, Yusuke; Hosoya, Takahiro; Kanda, Hiroaki; Kudo, Ayane; Okada, Norihide; Yagi, Takafumi; Nakata, Kazuaki; Mineki, Shigeru; Tokunaga, Eiji

    2015-01-01

    Label-free, non-invasive, rapid absorbance spectral imaging A(x,y,λ) microscopy of single live cells at 1.2 μm × 1.2 μm resolution with an NA = 0.85 objective was developed and applied to unicellular green algae Chlamydomonas reinhardtii. By introducing the fiber assembly to rearrange a two-dimensional image to the one-dimensional array to fit the slit of an imaging spectrograph equipped with a CCD detector, scan-free acquisition of three-dimensional information of A(x,y,λ) was realized. The space-resolved absorbance spectra of the eyespot, an orange organelle about 1 μm, were extracted from the green-color background in a chlorophyll-rich single live cell absorbance image. Characteristic absorbance change in the cell suspension after hydrogen photoproduction in C. reinhardtii was investigated to find a single 715-nm absorption peak was locally distributed within single cells. The formula to calculate the absorbance of cell suspensions from that of single cells was presented to obtain a quantitative, parameter-free agreement with the experiment. It is quantitatively shown that the average number of chlorophylls per cell is significantly underestimated when it is evaluated from the absorbance of the cell suspensions due to the package effect.

  4. Algal Energy Conversion and Capture

    NASA Astrophysics Data System (ADS)

    Hazendonk, P.

    2015-12-01

    We address the potential for energy conversions and capture for: energy generation; reduction in energy use; reduction in greenhouse gas emissions; remediation of water and air pollution; protection and enhancement of soil fertility. These processes have the potential to sequester carbon at scales that may have global impact. Energy conversion and capture strategies evaluate energy use and production from agriculture, urban areas and industries, and apply existing and emerging technologies to reduce and recapture energy embedded in waste products. The basis of biocrude production from Micro-algal feedstocks: 1) The nutrients from the liquid fraction of waste streams are concentrated and fed into photo bioreactors (essentially large vessels in which microalgae are grown) along with CO2 from flue gasses from down stream processes. 2) The algae are processed to remove high value products such as proteins and beta-carotenes. The advantage of algae feedstocks is the high biomass productivity is 30-50 times that of land based crops and the remaining biomass contains minimal components that are difficult to convert to biocrude. 3) The remaining biomass undergoes hydrothermal liquefaction to produces biocrude and biochar. The flue gasses of this process can be used to produce electricity (fuel cell) and subsequently fed back into the photobioreactor. The thermal energy required for this process is small, hence readily obtained from solar-thermal sources, and furthermore no drying or preprocessing is required keeping the energy overhead extremely small. 4) The biocrude can be upgraded and refined as conventional crude oil, creating a range of liquid fuels. In principle this process can be applied on the farm scale to the municipal scale. Overall, our primary food production is too dependent on fossil fuels. Energy conversion and capture can make food production sustainable.

  5. Osteoblastic differentiation and stress response of human mesenchymal stem cells exposed to alternating current electric fields

    PubMed Central

    2011-01-01

    Background Electric fields are integral to many biological events, from maintaining cellular homeostasis to embryonic development to healing. The application of electric fields offers substantial therapeutic potential, while optimal dosing regimens and the underlying mechanisms responsible for the positive clinical impact are poorly understood. Methods The purpose of this study was to track the differentiation profile and stress response of human bone marrow derived mesenchymal stem cells (hMSCs) undergoing osteogenic differentiation during exposure to a 20 mV/cm, 60 kHz electric field. Morphological and biochemical changes were imaged using endogenous two-photon excited fluorescence (TPEF) and quantitatively assessed through eccentricity calculations and extraction of the redox ratio from NADH, FAD and lipofuscin contributions. Real time reverse transcriptase-polymerase chain reactions (RT-PCR) were used to track osteogenic differentiation markers, namely alkaline phosphatase (ALP) and collagen type 1 (col1), and stress response markers, such as heat shock protein 27 (hsp27) and heat shock protein 70 (hsp70). Comparisons of collagen deposition between the stimulated hMSCs and controls were examined through second harmonic generation (SHG) imaging. Results Quantitative differences in cell morphology, as described through an eccentricity ratio, were found on days 2 and days 5 (p < 0.05) in samples exposed to the electric field. A delayed but two fold increase in ALP and col1 transcript was detected by week 2 (p < 0.05) in differentiating hMSCs exposed to an electric field in comparison to the nonstimulated controls. Upregulation in stress marker, hsp27, and type 1 collagen deposition were correlated with this response. Increases in NADH, FAD, and lipofuscin were traced in the stimulation group during the first week of field exposure with differences statistically significant on day 10 (p < 0.05). Changes in hsp27 expression correlate well with changes in lipofuscin

  6. Mass algal culture system

    DOEpatents

    Raymond, Lawrence P.

    1981-01-01

    An apparatus and process for the culture of algae in a liquid medium is disclosed. The medium circulates through an open trough and is exposed to an atmosphere which is temperature regulated. The nutrient content of the liquid medium is regulated to control the chemical composition growth and reproduction characteristics of the cultured algae. Before it is allowed to strike the medium, sunlight is passed through a filter to remove wavelengths which are not photosynthetically active. Heat energy can be recovered from the filter.

  7. Mass algal culture system

    DOEpatents

    Raymond, Lawrence P.

    1982-01-01

    An apparatus and process for the culture of algae in a liquid medium is disclosed. The medium circulates through an open trough and is exposed to an atmosphere which is temperature regulated. The nutrient content of the liquid medium is regulated to control the chemical composition growth and reproduction characteristics of the cultured algae. Before it is allowed to strike the medium, sunlight is passed through a filter to remove wavelengths which are not photosynthetically active. Heat energy can be recovered from the filter.

  8. Acute respiratory bronchiolitis: an ultrastructural and autoradiographic study of epithelial cell injury and renewal in Rhesus monkeys exposed to ozone

    SciTech Connect

    Castleman, W.L.; Dungworth, D.L.; Schwartz, L.W.; Tyler, W.S.

    1980-03-01

    The pathogenesis of acute respiratory bronchiolitis was examined in Rhesus monkeys exposed to 0.8 ppM ozone for 4 to 50 hours. Epithelial injury and renewal were qualitatively and quantitatively characterized by correlated techniques of scanning and transmission electron microscopy as well as by light-microscopic autoradiography following labeling with tritiated thymidine. Extensive degeneration and necrosis of Type 1 epithelial cells occurred on the respiratory bronchiolar wall during the initial 4 to 12 hours of exposure. Increased numbers of labeled epithelial cells were present in this region after 18 hours of exposure, and the highest labeling index (18%) was measured after 50 hours of exposure. Most (67 to 80%) of the labeled cells and all the mitotic epithelial cells (22) observed ultrastructurally were cuboidal bronchiolar epithelial cells. Of the labeled epithelial cells, 20 to 33% were Type 2 epithelial cells. After 50 hours of exposure the respiratory bronchiolar epithelium was hyperplastic. The predominant inflammatory cell in respiratory bronchiolar exudate was the alveolar macrophage. Monkeys that were exposed for 50 hours and allowed to recover in unozonized air for 7 days had incomplete resolution of respiratory bronchiolar epithelial hyperplasia. The results indicate that Type 1 epithelial cells lining respiratory bronchioles are the cell types most sensitive to injury and that both cuboidal bronchiolar epithelial cells and Type 2 epithelial cells function as stem cells in epithelial renewal.

  9. Miocene lacustrine algal reefs—southwestern Snake River Plain, Idaho

    NASA Astrophysics Data System (ADS)

    Straccia, Frances G.; Wilkinson, Bruce H.; Smith, Gerald R.

    1990-04-01

    The Hot Spring limestone is a shallow-water algal carbonate within a late Tertiary transgressive lacustrine sequence exposed in the southwestern Snake River Plain. This 5 m thick lensoid sequence crops out over an 80 km 2 area that closely approximates original areal extent of nearshore carbonate accumulation. Reefal bodies consist of closely packed algal cylinders, several decimeters in height, each of which includes a dense laminated carbonate wall surrounding porous digitate carbonate that radiates outward and upward from one or more hollow tubes. These coalesce upsection into separate vertical columns several meters in diameter. Moderately well-sorted terrigenous and molluscan debris deposited between columns during growth indicates these structures were resistant to wave erosion and, therefore, were true reefs. Thick rings of littoral carbonate surrounding the upper walls of each column record the final stages of reef development. Structural attributes exhibited by these Miocene carbonate bodies are also common to a number of Tertiary and Quaternary algal buildups reported from other lacustrine settings. Although features within the Hot Spring limestone are complex in gross morphology and structural detail, both columnar reefs and algal cylinders display little variation in size, shape, or internal structure between areas of varying water depth and wave energy, thus reflecting the importance of biological processes as well as physical processes during reef development.

  10. Study of Oxidative Stress in Human Lens Epithelial Cells Exposed to 1.8 GHz Radiofrequency Fields

    PubMed Central

    Ni, Shuang; Yu, Yibo; Zhang, Yidong; Wu, Wei; Lai, Kairan; Yao, Ke

    2013-01-01

    Objectives The aims of the present study were to determine oxidative stress and to explore possible reasons of reactive oxygen species (ROS) increase in human lens epithelial (HLE) B3 cells exposed to low intensity 1.8 GHz radiofrequency fields (RF). Methods The HLE B3 cells were divided into RF exposure and RF sham-exposure groups. The RF exposure intensity was at specific absorption rate (SAR) of 2, 3, or 4 W/kg. The ROS levels were measured by a fluorescent probe 2′7′-dichlorofluorescin diacetate (DCFH-DA) assay in the HLE B3 cells exposed to 1.8 GHz RF for 0.5, 1, and 1.5 h. Lipid peroxidation and cellular viability were detected by an MDA test and Cell Counting Kit-8 (CCK-8) assays, respectively, in the HLE B3 cells exposed to 1.8 GHz RF for 6, 12, and 24 h, respectively. The mRNA expression of SOD1, SOD2, CAT, and GPx1 genes and the expression of SOD1, SOD2, CAT, and GPx1 proteins was measured by qRT-PCR and Western blot assays in the HLE B3 cells exposed to 1.8 GHz RF for 1 h. Results The ROS and MDA levels significantly increased (P<0.05) in the RF exposure group and that the cellular viability, mRNA expression of four genes, and expression of four proteins significantly decreased (P<0.05) compared with the RF sham-exposure group. Conclusions Oxidative stress is present in HLE B3 cells exposed to 1.8 GHz low-intensity RF and that the increased production of ROS may be related to down-regulation of four antioxidant enzyme genes induced by RF exposure. PMID:23991100

  11. Susceptibility of oxidative stress on red blood cells exposed to gamma rays: hemorheological evaluation.

    PubMed

    Kim, Yu-Kyung; Kwon, Eun-Hee; Kim, Dong-Hyun; Won, Dong-Il; Shin, Sehyun; Suh, Jang-Soo

    2008-01-01

    Irradiation has been shown to induce biochemical changes in stored red blood cells (RBCs) and to generate reactive oxygen species (ROS). This study evaluated the hemorheological properties, the degree of lipid peroxidation and the oxidative susceptibility of irradiated RBCs. Furthermore, we investigated the radioprotective role of N-t-butyl hydroxylamine (NtBHA) against gamma-ray exposure of RBCs. RBC concentrates were irradiated with a minimum dose of 25 Gy, and were exposed to FeSO4 to examine the oxidative susceptibility. RBC deformability was evaluated by the use of a microfluidic ektacytometer, in relation to the hematological and biochemical properties. The deformability of the irradiated RBCs was significantly lower than that of control. Exposure to gamma rays significantly increased the mean corpuscular volume (MCV) and lipid peroxidation. Changes in RBC deformability were more prominent in irradiated RBCs than in non-irradiated RBCs also under conditions of oxidative stress. The deformability of NtBHA treated RBCs prior to irradiation was not altered as compared with irradiated RBCs not treated with NtBHA. In conclusion, irradiation reduces RBC deformability during storage and the irradiated RBCs seem susceptible to oxidative stress. NtBHA may not have a protective role against the effects of gamma-ray exposure in RBCs but further evaluation of NtBHA or another radioprotective compound is required.

  12. Ion transport into cells exposed to monopolar and bipolar nanosecond pulses.

    PubMed

    Schoenbach, Karl H; Pakhomov, Andrei G; Semenov, Iurii; Xiao, Shu; Pakhomova, Olga N; Ibey, Bennett L

    2015-06-01

    Experiments with CHO cells exposed to 60 and 300 ns pulsed electric fields with amplitudes in the range from several kV/cm to tens of kV/cm showed a decrease of the uptake of calcium ions by more than an order of magnitude when, immediately after a first pulse, a second one of opposite polarity was applied. This effect is assumed to be due to the reversal of the electrophoretic transport of ions through the electroporated membrane during the second phase of the bipolar pulse. This assumption, however, is only valid if electrophoresis is the dominant transport mechanism, rather than diffusion. Comparison of calculated calcium ion currents with experimental results showed that for nanosecond pulses, electrophoresis is at least as important as diffusion. By delaying the second pulse with respect to the first one, the effect of reverse electrophoresis is reduced. Consequently, separating nanosecond pulses of opposite polarity by up to approximately hundred microseconds allows us to vary the uptake of ions from very small values to those obtained with two pulses of the same polarity. The measured calcium ion uptake obtained with bipolar pulses also allowed us to determine the membrane pore recovery time. The calculated recovery time constants are on the order of 10 μs.

  13. Apoptosis of peripheral blood mononuclear cells in children exposed to arsenic and fluoride.

    PubMed

    Rocha-Amador, Diana O; Calderón, Jaqueline; Carrizales, Leticia; Costilla-Salazar, Rogelio; Pérez-Maldonado, Iván Nelinho

    2011-11-01

    In this study, we evaluated apoptosis induction in human immune cells in children exposed to arsenic (As) and fluoride (F). Children living in two areas in Mexico (Soledad de Graciano Sanchez (SGS) in San Luis Potosí and Colonia 5 de Febrero in Durango) were studied. Water, urine and blood samples were collected. Approximately 90% of the water samples in 5 de Febrero had As and F levels above the World Health Organization intervention guideline (10 μg/L and 1.5mg/L, respectively). In SGS, 0% of the water samples exceeded Mexican guidelines. Urinary As and F levels in children living in 5 de Febrero were significantly higher than the levels found in children living in SGS. In addition, the level of apoptosis was higher in children from the 5 de Febrero community when compared with the level of apoptosis in children living in SGS. Thus, in a worldwide context, our study demonstrates the health risks to children living in these regions.

  14. Ion transport into cells exposed to monopolar and bipolar nanosecond pulses

    PubMed Central

    Schoenbach, Karl H.; Pakhomov, Andrei G.; Semenov, Iurii; Xiao, Shu; Pakhomova, Olga N.; Ibey, Bennet L.

    2014-01-01

    Experiments with CHO cells exposed to 60 and 300 ns pulsed electric fields with amplitudes in the range from several kV/cm to tens of kV/cm, showed a decrease of the uptake of calcium ions by more than an order of magnitude when, immediately after a first pulse, a second one of opposite polarity was applied. This effect is assumed to be due to the reversal of the electrophoretic transport of ions through the electroporated membrane during the second phase of the bipolar pulse. This assumption, however, is only valid if electrophoresis is the dominant transport mechanism, rather than diffusion. Comparison of calculated calcium ion currents with experimental results showed that for nanosecond pulses, electrophoresis is at least as important as diffusion. By delaying the second pulse with respect to the first one, the effect of reverse electrophoresis is reduced. Consequently, separating nanosecond pulses of opposite polarity by up to approximately hundred microseconds allows us to vary the uptake of ions from very small values to that obtained with two pulses of the same polarity. The measured calcium ion uptake obtained with bipolar pulses also allowed us to determine the membrane pore recovery time. The calculated recovery time constants are on the order of ten microseconds. PMID:25212701

  15. Knockout of Ccr2 alleviates photoreceptor cell death in rodent retina exposed to chronic blue light.

    PubMed

    Hu, Zizhong; Zhang, Yi; Wang, Junling; Mao, Pingan; Lv, Xuehua; Yuan, Songtao; Huang, Zhengru; Ding, Yuzhi; Xie, Ping; Liu, Qinghuai

    2016-11-10

    Age-related macular degeneration (AMD), the leading cause of visual loss after the age of 60 years, is a degenerative retinal disease involving a variety of environmental and hereditary factors. Although it has been implicated that immune system is involved in the disease progression, the exact role that microglia has is still unclear. Here we demonstrated that knockout of Ccr2 gene could alleviate photoreceptor cell death in mice retinas exposed to chronic blue light. In Ccr2(-/-) mice, a damaged microglia recruitment was shown in retina and this could protect the visual function in electroretinogram and alleviate the photoreceptor apoptosis, which thus helped attenuate the blue light-induced retinopathy. We further found an increased co-location of NLRP3, Iba-1, and IL-1β in fluorescence and a concomitant increased protein expression of NLRP3, caspase-1, and IL-1β in western blotting in chronic blue light-induced retinopathy. Moreover, the activation of microglia and their cellular NLRP3 inflammasomes occurred as an earlier step before the structural and functional damage of the mice retinas, which collectively supported that microglial NLRP3 inflammasome might be the key to the chronic blue light-induced retinopathy.

  16. Persistent oxidative stress in human neural stem cells exposed to low fluences of charged particles.

    PubMed

    Baulch, Janet E; Craver, Brianna M; Tran, Katherine K; Yu, Liping; Chmielewski, Nicole; Allen, Barrett D; Limoli, Charles L

    2015-08-01

    Exposure to the space radiation environment poses risks for a range of deleterious health effects due to the unique types of radiation encountered. Galactic cosmic rays are comprised of a spectrum of highly energetic nuclei that deposit densely ionizing tracks of damage along the particle trajectory. These tracks are distinct from those generated by the more sparsely ionizing terrestrial radiations, and define the geometric distribution of the complex cellular damage that results when charged particles traverse the tissues of the body. The exquisite radiosensitivity of multipotent neural stem and progenitor cells found within the neurogenic regions of the brain predispose the central nervous system to elevated risks for radiation induced sequelae. Here we show that human neural stem cells (hNSC) exposed to different charged particles at space relevant fluences exhibit significant and persistent oxidative stress. Radiation induced oxidative stress was found to be most dependent on total dose rather than on the linear energy transfer of the incident particle. The use of redox sensitive fluorogenic dyes possessing relative specificity for hydroxyl radicals, peroxynitrite, nitric oxide (NO) and mitochondrial superoxide confirmed that most irradiation paradigms elevated reactive oxygen and nitrogen species (ROS and RNS, respectively) in hNSC over a 1 week interval following exposure. Nitric oxide synthase (NOS) was not the major source of elevated nitric oxides, as the use of NOS inhibitors had little effect on NO dependent fluorescence. Our data provide extensive evidence for the capability of low doses of charged particles to elicit marked changes in the metabolic profile of irradiated hNSC. Radiation induced changes in redox state may render the brain more susceptible to the development of neurocognitive deficits that could affect an astronaut's ability to perform complex tasks during extended missions in deep space.

  17. Fibrogenic response of hepatic stellate cells in ovariectomised rats exposed to ketogenic diet.

    PubMed

    Bobowiec, R; Wojcik, M; Jaworska-Adamu, J; Tusinska, E

    2013-02-01

    The discrepancy about the role of estrogens in hepatic fibrogenesis and lack of studies addressed of ketogenic diet (KD) on hepatic stellate cells (HSC), prompted us to investigate the activity of HSC in control, KD- and thioacetamide (TAA)-administrated rats with different plasma concentration of estradiol (E2). HSC were isolated by the collagenase perfusion methods and separated by the Percoll gradient centrifugation. After the 4(th) and 8(th) day of incubation, lysates of HSC and the media were collected for further analysis. The HSC derived from KD-rats released remarkably more transforming growth factor (TGF)-β1 than cells obtained from animals fed with a standard diet. The ovariectomy of KD-rats markedly intensified the secretion of this fibrogenic cytokine on the 8(th) day of incubation (201.33 ±1 7.15 pg/ml). In HSC of rats exposed to E2, the TGF-β1 concentration did not exceed 157 ± 34.39 pg/ml. In respect to the collagen type I, the HSC obtained from ovariectomised KD-rats released an augmented amount of this ECM protein after the 8(th) day of culture (1.83 ± 0.14 U/ml). In the same time, higher quantities of ASMA appeared in the KD rats (1.41 ± 0.3 pg/mg protein). Exposition of rats to E2 did not markedly decrease the amount of ASMA. In summary, KD was able to induce morphological and functional changes in HSC, especially derived from rats deprived of ovarian estrogens. However, the preservation of E2 in ovariectomised rats didn't substantially alter the activation of HSC.

  18. Speciation of arsenic in Euglena gracilis cells exposed to As(V).

    PubMed

    Miot, Jennyfer; Morin, Guillaume; Skouri-Panet, Fériel; Férard, Céline; Poitevin, Antonine; Aubry, Emmanuel; Ona-Nguema, Georges; Juillot, Farid; Guyot, François; Brown, Gordon E

    2009-05-01

    Euglena gracilis is a photosynthetic eukaryote ubiquitous in arsenic-polluted acid mine drainages and is locally exposed to As(III) and As(V) concentrations up to 250 and 100 mg L(-1), respectively. Here, arsenic speciation in E. graciliswas determined by X-ray absorption spectroscopy and selected (bio)chemical methods on cells grown at nonlimiting phosphate concentrations. Our results suggest the following detoxification scheme: (1) uptake of As(V) from solution in competition with phosphate, (2) intracellular reduction to As(III), (3) complexation by cytoplasmic proteic thiol ligands of low molecular weight, and (4) As(III) export from the cell. However, at As(V) concentrations >100 mg L(-1), growth rate is markedly lowered and As(V) remains mostly unreduced during the extended lag period. Intracellular As(V) is found to be exclusively concentrated in the membrane + nucleus fraction, suggesting that arsenate could substitute for phosphate groups in membranes or in phosphate-containing macromolecules. Thus, arsenic species are partitioned, with As(III)-thiol compounds concentrated in the cytoplasmic proteic pool and As(V)-compounds associated with the membrane + nucleus fraction. The increasing growth delay observed with increasing initial As(V) concentration in the culture medium is proposed to result from the combination of a higher As(V) uptake and limiting intracellular As(V) reduction rate and As(III) export rate. Under high As(V) exposure conditions (200 mg L(-1)) the reduction step is found to be the most limiting step for detoxification.

  19. Host cell reactivation of sunlamp-exposed adenovirus in fibroblasts from patients with Bloom's syndrome, ataxia telangiectasia, and Huntington's disease

    SciTech Connect

    Rainbow, A.J. )

    1991-01-01

    In this study, a sensitive host cell reactivation (HCR) technique was used to examine the repair capacity for DNA damaged by sunlamp exposure in fibroblast strains derived from 5 normal individuals and 8 patients representing three different diseases associated with DNA repair deficiencies. Adenovirus type 2 (Ad 2) was exposed to radiation from a GE 275 W sunlamp and subsequently used to infect fibroblast monolayers. At 48 hr after infection, cells were scored for the presence of viral structural antigens (Vag) using indirect immunofluorescent staining. Previous reports using this technique showed a substantial reduction in the HCR of sunlamp-exposed Ad 2 for infection of excision repair deficient fibroblasts from patients with xeroderma pigmentosum. In contrast, the HCR of Vag synthesis for sunlamp-exposed Ad 2 was in the normal range for the three ataxia telangiectasia, three Bloom's syndrome, and two Huntington's disease fibroblasts strains.

  20. B cells play key roles in th2-type airway immune responses in mice exposed to natural airborne allergens.

    PubMed

    Drake, Li Yin; Iijima, Koji; Hara, Kenichiro; Kobayashi, Takao; Kephart, Gail M; Kita, Hirohito

    2015-01-01

    Humans are frequently exposed to various airborne allergens. In addition to producing antibodies, B cells participate in immune responses via various mechanisms. The roles of B cells in allergic airway inflammation and asthma have been controversial. We examined the functional importance of B cells in a mouse model of asthma, in which mice were exposed repeatedly to common airborne allergens. Naïve wild-type BALB/c mice or B cell-deficient JH-/- mice were exposed intranasally to a cocktail of allergen extracts, including Alternaria, Aspergillus, and house dust mite, every other day for two weeks. Ovalbumin was included in the cocktail to monitor the T cell immune response. Airway inflammation, lung pathology, and airway reactivity were analyzed. The airway exposure of naïve wild type mice to airborne allergens induced robust eosinophilic airway inflammation, increased the levels of Th2 cytokines and chemokines in the lung, and increased the reactivity to inhaled methacholine. These pathological changes and immune responses were attenuated in B cell-deficient JH-/- mice. The allergen-induced expansion of CD4+ T cells was impaired in the lungs and draining lymph nodes of JH-/- mice. Furthermore, lymphocytes from JH-/- mice failed to produce Th2 cytokines in response to ovalbumin re-stimulation in vitro. Our results suggest that B cells are required for the optimal development of Th2-type immune responses and airway inflammation when exposed to common airborne allergens. The therapeutic targeting of B cells may be beneficial to treat asthma in certain patients.

  1. Potential of carbon nanotubes in algal biotechnology.

    PubMed

    Lambreva, Maya Dimova; Lavecchia, Teresa; Tyystjärvi, Esa; Antal, Taras Kornelievich; Orlanducci, Silvia; Margonelli, Andrea; Rea, Giuseppina

    2015-09-01

    A critical mass of knowledge is emerging on the interactions between plant cells and engineered nanomaterials, revealing the potential of plant nanobiotechnology to promote and support novel solutions for the development of a competitive bioeconomy. This knowledge can foster the adoption of new methodological strategies to empower the large-scale production of biomass from commercially important microalgae. The present review focuses on the potential of carbon nanotubes (CNTs) to enhance photosynthetic performance of microalgae by (i) widening the spectral region available for the energy conversion reactions and (ii) increasing the tolerance of microalgae towards unfavourable conditions occurring in mass production. To this end, current understanding on the mechanisms of uptake and localization of CNTs in plant cells is discussed. The available ecotoxicological data were used in an attempt to assess the feasibility of CNT-based applications in algal biotechnology, by critically correlating the experimental conditions with the observed adverse effects. Furthermore, main structural and physicochemical properties of single- and multi-walled CNTs and common approaches for the functionalization and characterization of CNTs in biological environment are presented. Here, we explore the potential that nanotechnology can offer to enhance functions of algae, paving the way for a more efficient use of photosynthetic algal systems in the sustainable production of energy, biomass and high-value compounds.

  2. Glycophorin A somatic cell mutation frequencies in Finnish reinforced plastics workers exposed to styrene.

    PubMed

    Bigbee, W L; Grant, S G; Langlois, R G; Jensen, R H; Anttila, A; Pfäffli, P; Pekari, K; Norppa, H

    1996-10-01

    We have used the glycophorin A (GPA) in vivo somatic cell mutation assay to assess the genotoxic potential of styrene exposure in 47 reinforced plastics workers occupationally exposed to styrene and 47 unexposed controls matched for age, gender, and active smoking status. GPA variant erythrocyte frequencies (Vf), reflecting GPA allele loss (phi/N) and allele loss and duplication (N/N) somatic mutations arising in vivo in the erythroid progenitor cells of individuals of GPA M/N heterozygous genotype, were flow cytometrically determined in peripheral blood samples from these subjects. Measurements of styrene exposure of the workers at the time of blood sampling showed a mean 8-h time-weighted average (TWA8-h) styrene concentration of 155 mg/m3 (37 ppm) in the breathing zone. Mean urinary concentrations of the styrene metabolites mandelic acid (MA) and mandelic acid plus phenyl glyoxylic acid (MA+PGA) were 4.4 mmol/liter (after workshift) and 2.1 mmol/liter (next morning), respectively. Multivariate analysis of covariance on log-transformed GPA Vf data with models allowing adjustment for age, gender, smoking status, and styrene exposure showed that N/N Vf were nearly significantly increased among all of the exposed workers (adjusted geometric mean, 6.3 per million versus 5.0 in the controls; P = 0.058) and were statistically significantly elevated (adjusted geometric mean, 6.8 versus 5.0 in the controls; P = 0.036) among workers classified into a high-exposure group according to personal TWA8-h concentration of styrene in the breathing zone of > or = 85 mg/m3 (20 ppm; Finnish threshold limit value). Women in this high exposure group showed especially elevated N/N Vf (adjusted geometric mean 8.5 versus 5.3 in control women; P = 0.020); this elevation was also significant if urinary MA+PGA of > or = 1.2 mmol/liter was used as the basis of classification (adjusted geometric mean, 8.3; P = 0.030). The occupational exposure could not be shown to influence phi/N Vf

  3. IN VITRO EFFECTS OF PARTICULATE MATTER ON AIRWAY EPITHELIAL CELLS ISOLATED FROM CONCENTRATED AIR PARTICLES-EXPOSED SPONTANEOUS HYPERTENSIVE RATS

    EPA Science Inventory

    In vitro effects of particulate matter on airway epithelial cells isolated from concentrated air particles-exposed spontaneous hypertensive rats

    Ines Pagan, Urmila Kodavanti, Paul Evansky, Daniel L Costa and Janice A Dye. U.S. Environmental Protection Agency, ORD, National...

  4. Cytogenetic biomonitoring of Brazilian workers exposed to pesticides: micronucleus analysis in buccal epithelial cells of soybean growers.

    PubMed

    Bortoli, Giorgia Moura de; Azevedo, Mariana Barbieri de; Silva, Luciano Basso da

    2009-04-30

    Pesticides have been considered potential chemical mutagens and various agrochemical ingredients possess mutagenic properties. Biomonitoring provides a useful tool to estimate the genetic risk from exposure to a complex mixture of chemicals. In general genetic damage associated with pesticides occurs in human populations subject to high exposure levels due to intensive use, misuse or failure of control measures. Few studies have been carried out using the micronucleus (MN) analysis in buccal cells of farm workers and, from the available data, only one has found a positive relationship. Micronuclei were analyzed in 29 Brazilian workers exposed to pesticides in soybean fields and in 37 non-exposed individuals. The results obtained indicate that the mean number of cells with MN in the exposed group (3.55+/-2.13) was significantly higher than in the control group (1.78+/-1.23). The number of cells with MN was not influenced by age, smoking habit, smoking time, number of cigarettes/day, alcohol consumption and years of exposure to pesticides. The genotoxic potential of the pesticides used in soybean fields may explain the detectable increase of cells with MN in exposed workers.

  5. Effect of angiopoietin-like protein 4 on rat pulmonary microvascular endothelial cells exposed to LPS

    PubMed Central

    WANG, YUXI; CHEN, HAILONG; LI, HAILONG; ZHANG, JINGWEN; GAO, YANYAN

    2013-01-01

    Pulmonary microvascular endothelial cells (PMVECs) possess highly proliferative and angiogenic capacities and are localized at the critical interface between the blood and microvessel wall; they are the primary targets of inflammatory cytokines during lung inflammation. Angiopoietin-like protein 4 (Angptl4) is a circulating protein that has recently been implicated in the regulation of angiogenesis and metastasis. This study aimed to investigate the effect of Angptl4 on rat PMVECs (RPMVECs) exposed to lipopolysaccharide (LPS). The cell culture was stimulated with LPS. Total Angptl4 cDNA was obtained from Source BioScience. The PCR product was cloned into the pcDNA3.1-eGFP or the pcDNA3.1-eGFP-Angptl4 vector, which were then transfected into the RPMVECs using SuperFect transfection reagent. The Angptl4 mRNA levels, protein levels and cell morphology of the RPMVECs in the experimental groups were detected using real time-PCR, western blot analysis, MTT assay, ELISA and confocal microscopy methods, respectively. The Angptl4 expression vector, pcDNA3.1-eGFP-Angptl4, was successfully constructed. The Angptl4 mRNA level in the LPS-pcDNA3.1-eGFP-transfected group (blank control) was slightly increased and was significantly higher in the experimental group compared with the empty vector and blank control group with significant differences. Pro-apoptotic caspase-8, -9 and Bax protein were inhibited, while p-AKT/AKT and p-MEK1/2 protein expression was also decreased. The rosiglitazone group had significantly decreased levels of the inflammatory cytokine, tumor necrosis factor (TNF)-α (P<0.01). The overexpression of Angptl4 inhibited the LPS-induced increase in the permeability of the RPMVECs, which was associated with the depolymerization of central F-actin in the RPMVECs. In conclusion, our study demonstrates that the overexpression of Angptl4 exerts protective, anti-inflammatory and anti-angiogenic effects. It represents a novel therapeutic target gene for the treatment

  6. Responses of well-differentiated nasal epithelial cells exposed to particles: Role of the epithelium in airway inflammation

    SciTech Connect

    Auger, Floriane; Gendron, Marie-Claude; Chamot, Christophe; Marano, Francelyne; Dazy, Anne-Catherine . E-mail: dazy@paris7.jussieu.fr

    2006-09-15

    Numerous epidemiological studies support the contention that ambient air pollution particles can adversely affect human health. To explain the acute inflammatory process in airways exposed to particles, a number of in vitro studies have been performed on cells grown submerged on plastic and poorly differentiated, and on cell lines, the physiology of which is somewhat different from that of well-differentiated cells. In order to obtain results using a model system in which epithelial cells are similar to those of the human airway in vivo, apical membranes of well-differentiated human nasal epithelial (HNE) cells cultured in an air-liquid interface (ALI) were exposed for 24 h to diesel exhaust particles (DEP) and Paris urban air particles (PM{sub 2.5}). DEP and PM{sub 2.5} (10-80 {mu}g/cm{sup 2}) stimulated both IL-8 and amphiregulin (ligand of EGFR) secretion exclusively towards the basal compartment. In contrast, there was no IL-1{beta} secretion and only weak non-reproducible secretion of TNF-{alpha}. IL-6 and GM-CSF were consistently stimulated towards the apical compartment and only when cells were exposed to PM{sub 2.5}. ICAM-1 protein expression on cell surfaces remained low after particle exposure, although it increased after TNF-{alpha} treatment. Internalization of particles, which is believed to initiate oxidative stress and proinflammatory cytokine expression, was restricted to small nanoparticles ({<=} 40 nm). Production of reactive oxygen species (ROS) was detected, and DEP were more efficient than PM{sub 2.5}. Collectively, our results suggest that airway epithelial cells exposed to particles augment the local inflammatory response in the lung but cannot alone initiate a systemic inflammatory response.

  7. Stress-Survival Gene Identification From an Acid Mine Drainage Algal Mat Community

    NASA Astrophysics Data System (ADS)

    Urbina-Navarrete, J.; Fujishima, K.; Paulino-Lima, I. G.; Rothschild-Mancinelli, B.; Rothschild, L. J.

    2014-12-01

    Microbial communities from acid mine drainage environments are exposed to multiple stressors to include low pH, high dissolved metal loads, seasonal freezing, and desiccation. The microbial and algal communities that inhabit these niche environments have evolved strategies that allow for their ecological success. Metagenomic analyses are useful in identifying species diversity, however they do not elucidate the mechanisms that allow for the resilience of a community under these extreme conditions. Many known or predicted genes encode for protein products that are unknown, or similarly, many proteins cannot be traced to their gene of origin. This investigation seeks to identify genes that are active in an algal consortium during stress from living in an acid mine drainage environment. Our approach involves using the entire community transcriptome for a functional screen in an Escherichia coli host. This approach directly targets the genes involved in survival, without need for characterizing the members of the consortium.The consortium was harvested and stressed with conditions similar to the native environment it was collected from. Exposure to low pH (< 3.2), high metal load, desiccation, and deep freeze resulted in the expression of stress-induced genes that were transcribed into messenger RNA (mRNA). These mRNA transcripts were harvested to build complementary DNA (cDNA) libraries in E. coli. The transformed E. coli were exposed to the same stressors as the original algal consortium to select for surviving cells. Successful cells incorporated the transcripts that encode survival mechanisms, thus allowing for selection and identification of the gene(s) involved. Initial selection screens for freeze and desiccation tolerance have yielded E. coli that are 1 order of magnitude more resistant to freezing (0.01% survival of control with no transcript, 0.2% survival of E. coli with transcript) and 3 orders of magnitude more resistant to desiccation (0.005% survival of

  8. Relationship of CD86 surface marker expression and cytotoxicity on dendritic cells exposed to chemical allergen

    SciTech Connect

    Hulette, Ben C.; Ryan, Cindy A.; Gildea, Lucy A.; Gerberick, G. Frank . E-mail: gerberick.gf@pg.com

    2005-12-01

    Human peripheral blood-derived dendritic cells (DC) respond to a variety of chemical allergens by up-regulating expression of the co-stimulatory molecule CD86. It has been postulated that this measure might provide the basis for an in vitro alternative approach for the identification of skin sensitizing chemicals. We recently reported that DC, exposed in culture to the highest non-cytotoxic concentrations of various chemical allergens, displayed marginal up-regulation of membrane CD86 expression; the interpretation being that such changes were insufficiently sensitive for the purposes of hazard identification. For the work presented here, immature DC were derived from human monocytes and treated with the chemical allergens 2,4-dinitrobenzenesulfonic acid (DNBS), nickel sulfate (NiSO{sub 4}), p-phenylenediamine (PPD), Bandrowski's base (BB), hydroquinone (HQ) and propyl gallate (PG) for 48 h at concentrations which induced both no to slight to moderate cytotoxicity. For comparison, DC were treated with the irritants sodium dodecyl sulfate (SDS), benzoic acid (BA), and benzalkonium chloride (BZC) at concentrations resulting in comparable levels of cytotoxicity. CD86 expression, as measured by flow cytometry, was consistently up-regulated (ranging from 162 to 386% control) on DC treated with concentrations of chemical allergens that induced approximately 10-15% cytotoxicity. The irritants BA and BZC did not induce up-regulation of CD86 expression when tested at concentrations that induced similar levels of cytotoxicity. SDS, however, up-regulated CD86 expression to 125-138% of control in 2/4 preparations when tested at concentrations which induced similar toxicity. Our results confirm that chemical allergens up-regulate CD86 expression on blood-derived DC and illustrate further that up-regulation of CD86 surface marker expression is more robust when DC are treated with concentrations of chemical allergen that induce slight to moderate cytotoxicity.

  9. BIGEL analysis of gene expression in HL60 cells exposed to X rays or 60 Hz magnetic fields

    NASA Technical Reports Server (NTRS)

    Balcer-Kubiczek, E. K.; Zhang, X. F.; Han, L. H.; Harrison, G. H.; Davis, C. C.; Zhou, X. J.; Ioffe, V.; McCready, W. A.; Abraham, J. M.; Meltzer, S. J.

    1998-01-01

    We screened a panel of 1,920 randomly selected cDNAs to discover genes that are differentially expressed in HL60 cells exposed to 60 Hz magnetic fields (2 mT) or X rays (5 Gy) compared to unexposed cells. Identification of these clones was accomplished using our two-gel cDNA library screening method (BIGEL). Eighteen cDNAs differentially expressed in X-irradiated compared to control HL60 cells were recovered from a panel of 1,920 clones. Differential expression in experimental compared to control cells was confirmed independently by Northern blotting of paired total RNA samples hybridized to each of the 18 clone-specific cDNA probes. DNA sequencing revealed that 15 of the 18 cDNA clones produced matches with the database for genes related to cell growth, protein synthesis, energy metabolism, oxidative stress or apoptosis (including MYC, neuroleukin, copper zinc-dependent superoxide dismutase, TC4 RAS-like protein, peptide elongation factor 1alpha, BNIP3, GATA3, NF45, cytochrome c oxidase II and triosephosphate isomerase mRNAs). In contrast, BIGEL analysis of the same 1,920 cDNAs revealed no differences greater than 1.5-fold in expression levels in magnetic-field compared to sham-exposed cells. Magnetic-field-exposed and control samples were analyzed further for the presence of mRNA encoding X-ray-responsive genes by hybridization of the 18 specific cDNA probes to RNA from exposed and control HL60 cells. Our results suggest that differential gene expression is induced in approximately 1% of a random pool of cDNAs by ionizing radiation but not by 60 Hz magnetic fields under the present experimental conditions.

  10. BIGEL analysis of gene expression in HL60 cells exposed to X rays or 60 Hz magnetic fields.

    PubMed

    Balcer-Kubiczek, E K; Zhang, X F; Han, L H; Harrison, G H; Davis, C C; Zhou, X J; Ioffe, V; McCready, W A; Abraham, J M; Meltzer, S J

    1998-12-01

    We screened a panel of 1,920 randomly selected cDNAs to discover genes that are differentially expressed in HL60 cells exposed to 60 Hz magnetic fields (2 mT) or X rays (5 Gy) compared to unexposed cells. Identification of these clones was accomplished using our two-gel cDNA library screening method (BIGEL). Eighteen cDNAs differentially expressed in X-irradiated compared to control HL60 cells were recovered from a panel of 1,920 clones. Differential expression in experimental compared to control cells was confirmed independently by Northern blotting of paired total RNA samples hybridized to each of the 18 clone-specific cDNA probes. DNA sequencing revealed that 15 of the 18 cDNA clones produced matches with the database for genes related to cell growth, protein synthesis, energy metabolism, oxidative stress or apoptosis (including MYC, neuroleukin, copper zinc-dependent superoxide dismutase, TC4 RAS-like protein, peptide elongation factor 1alpha, BNIP3, GATA3, NF45, cytochrome c oxidase II and triosephosphate isomerase mRNAs). In contrast, BIGEL analysis of the same 1,920 cDNAs revealed no differences greater than 1.5-fold in expression levels in magnetic-field compared to sham-exposed cells. Magnetic-field-exposed and control samples were analyzed further for the presence of mRNA encoding X-ray-responsive genes by hybridization of the 18 specific cDNA probes to RNA from exposed and control HL60 cells. Our results suggest that differential gene expression is induced in approximately 1% of a random pool of cDNAs by ionizing radiation but not by 60 Hz magnetic fields under the present experimental conditions.

  11. USING PROTEOMICS TO MONITOR PROTEIN EXPRESSION IN HUMAN CELLS EXPOSED TO CARCINOGENS

    EPA Science Inventory

    People are continuously exposed exogenously to varying amounts of chemicals that have been shown to have carcinogenic properties in experimental systems. It has been estimated that exposure to environmental chemical carcinogens in the environment may contribute significantly to t...

  12. Differential effects in cells exposed to ultra-short, high intensity electric fields: cell survival, DNA damage, and cell cycle analysis.

    PubMed

    Stacey, M; Stickley, J; Fox, P; Statler, V; Schoenbach, K; Beebe, S J; Buescher, S

    2003-12-09

    High power, nanosecond pulsed electric field (nsPEF) effects have been focused on bacterial decontamination, but the impact on mammalian cells is now being revealed. During nsPEF applications, electrical pulses of 10, 60 or 300 ns durations were applied to cells using electric field amplitudes as high as 300 kV/cm. Because of the ultra-short pulse durations, the energy transferred to cells is negligible, and only non-thermal effects are observed. We investigated the genotoxicity of nsPEF on adherent and non-adherent cell lines including 10 human lines and one mouse cell line with different origin and growth characteristics. We present data examining the effects of nsPEF exposure on cell survival assessed by clonogenic formation or live cell count; DNA damage determined by the comet assay and chromosome aberrations; and cell cycle parameters by measuring the mitotic indices of exposed cells. Using each of these indicators, we observed differential effects among cell types with non-adherent cells being more sensitive to the genotoxic effects of nsPEF exposures than adherent cells. Non-adherent cultures showed a rapid decrease in cell viability (90%), induction of DNA damage, and a decrease in the number of cells reaching mitosis after one 60 ns pulse with an electric field intensity of 60 kV/cm. These effects were not observed in cells grown as adherent cultures, with the exception of the mouse 3T3 cell line, which showed survival characteristics similar to non-adherent cultures. These data suggest that nsPEF genotoxicity may be cell type specific, and therefore have potential applications in the selective removal of one cell type from another, for example, in diseased states.

  13. Monitoring and removal of cyanobacterial toxins from drinking water by algal-activated carbon.

    PubMed

    Ibrahim, Wael M; Salim, Emad H; Azab, Yahia A; Ismail, Abdel-Hamid M

    2016-10-01

    Microcystins (MCs) are the most potent toxins that can be produced by cyanobacteria in drinking water supplies. This study investigated the abundance of toxin-producing algae in 11 drinking water treatment plants (DWTPs). A total of 26 different algal taxa were identified in treated water, from which 12% were blue green, 29% were green, and 59% were diatoms. MC levels maintained strong positive correlations with number of cyanophycean cells in raw and treated water of different DWTPs. Furthermore, the efficiency of various algal-based adsorbent columns used for the removal of these toxins was evaluated. The MCs was adsorbed in the following order: mixed algal-activated carbon (AAC) ≥ individual AAC > mixed algal powder > individual algal powder. The results showed that the AAC had the highest efficient columns capable of removing 100% dissolved MCs from drinking water samples, thereby offering an economically feasible technology for efficient removal and recovery of MCs in DWTPs.

  14. Abscisic acid signalling determines susceptibility of bundle sheath cells to photoinhibition in high light-exposed Arabidopsis leaves

    PubMed Central

    Gorecka, Magdalena; Alvarez-Fernandez, Ruben; Slattery, Katie; McAusland, Lorna; Davey, Phillip A.; Karpinski, Stanislaw; Lawson, Tracy; Mullineaux, Philip M.

    2014-01-01

    The rapid induction of the bundle sheath cell (BSC)-specific expression of ASCORBATE PEROXIDASE2 (APX2) in high light (HL)-exposed leaves of Arabidopsis thaliana is, in part, regulated by the hormone abscisic acid (ABA) produced by vascular parenchyma cells. In this study, we provide more details of the ABA signalling that regulates APX2 expression and consider its importance in the photosynthetic responses of BSCs and whole leaves. This was done using a combination of analyses of gene expression and chlorophyll a fluorescence of both leaves and individual BSCs and mesophyll cells. The regulation of APX2 expression occurs by the combination of the protein kinase SnRK2.6 (OST1):protein phosphatase 2C ABI2 and a Gα (GPA1)-regulated signalling pathway. The use of an ost1-1/gpa1-4 mutant established that these signalling pathways are distinct but interact to regulate APX2. In HL-exposed leaves, BSC chloroplasts were more susceptible to photoinhibition than those of mesophyll cells. The activity of the ABA-signalling network determined the degree of susceptibility of BSCs to photoinhibition by influencing non-photochemical quenching. By contrast, in HL-exposed whole leaves, ABA signalling did not have any major influence on their transcriptomes nor on their susceptibility to photoinhibition, except where guard cell responses were observed. PMID:24591719

  15. Luminescent Solar Concentrators in the Algal Industry

    NASA Astrophysics Data System (ADS)

    Hellier, Katie; Corrado, Carley; Carter, Sue; Detweiler, Angela; Bebout, Leslie

    2013-03-01

    Today's industry for renewable energy sources and highly efficient energy management systems is rapidly increasing. Development of increased efficiency Luminescent Solar Concentrators (LSCs) has brought about new applications for commercial interests, including greenhouses for agricultural crops. This project is taking first steps to explore the potential of LSCs to enhance production and reduce costs for algae and cyanobacteria used in biofuels and nutraceuticals. This pilot phase uses LSC filtered light for algal growth trials in greenhouses and laboratory experiments, creating specific wavelength combinations to determine effects of discrete solar light regimes on algal growth and the reduction of heating and water loss in the system. Enhancing the optimal spectra for specific algae will not only increase production, but has the potential to lessen contamination of large scale production due to competition from other algae and bacteria. Providing LSC filtered light will reduce evaporation and heating in regions with limited water supply, while the increased energy output from photovoltaic cells will reduce costs of heating and mixing cultures, thus creating a more efficient and cost effective production system.

  16. Exploiting algal NADPH oxidase for biophotovoltaic energy.

    PubMed

    Anderson, Alexander; Laohavisit, Anuphon; Blaby, Ian K; Bombelli, Paolo; Howe, Christopher J; Merchant, Sabeeha S; Davies, Julia M; Smith, Alison G

    2016-01-01

    Photosynthetic microbes exhibit light-dependent electron export across the cell membrane, which can generate electricity in biological photovoltaic (BPV) devices. How electrons are exported remains to be determined; the identification of mechanisms would help selection or generation of photosynthetic microbes capable of enhanced electrical output. We show that plasma membrane NADPH oxidase activity is a significant component of light-dependent generation of electricity by the unicellular green alga Chlamydomonas reinhardtii. NADPH oxidases export electrons across the plasma membrane to form superoxide anion from oxygen. The C. reinhardtii mutant lacking the NADPH oxidase encoded by RBO1 is impaired in both extracellular superoxide anion production and current generation in a BPV device. Complementation with the wild-type gene restores both capacities, demonstrating the role of the enzyme in electron export. Monitoring light-dependent extracellular superoxide production with a colorimetric assay is shown to be an effective way of screening for electrogenic potential of candidate algal strains. The results show that algal NADPH oxidases are important for superoxide anion production and open avenues for optimizing the biological component of these devices.

  17. Increase in DNA damage in lymphocytes and micronucleus frequency in buccal cells in silica-exposed workers.

    PubMed

    Halder, Ajanta; De, Madhusnata

    2012-01-01

    The alkaline single cell gel electrophoresis (comet assay) was applied to study the genotoxic properties of silica in human peripheral blood lymphocytes (PBL). The study was designed to evaluate the DNA damage of lymphocytes and the end points like micronuclei from buccal smears in a group of 45 workers, occupationally exposed to silica, from small mines and stone quarries. The results were compared to 20 sex and age matched normal individuals. There was a statistically significant difference in the damage levels between the exposed group and the control groups. The types of damages (type I -type 1V) were used to measure the DNA damage. The numbers of micronuclei were higher in the silica-exposed population. The present study suggests that the silica exposure can induce lymphocyte DNA damage and produces significant variation of micronuclei in buccal smear.

  18. Algal biofuels: challenges and opportunities.

    PubMed

    Leite, Gustavo B; Abdelaziz, Ahmed E M; Hallenbeck, Patrick C

    2013-10-01

    Biodiesel production using microalgae is attractive in a number of respects. Here a number of pros and cons to using microalgae for biofuels production are reviewed. Algal cultivation can be carried out using non-arable land and non-potable water with simple nutrient supply. In addition, algal biomass productivities are much higher than those of vascular plants and the extractable content of lipids that can be usefully converted to biodiesel, triacylglycerols (TAGs) can be much higher than that of the oil seeds now used for first generation biodiesel. On the other hand, practical, cost-effective production of biofuels from microalgae requires that a number of obstacles be overcome. These include the development of low-cost, effective growth systems, efficient and energy saving harvesting techniques, and methods for oil extraction and conversion that are environmentally benign and cost-effective. Promising recent advances in these areas are highlighted.

  19. Algal blooms and public health

    SciTech Connect

    Epstein, P.R. . Harvard Medical School)

    1993-06-01

    Alterations in coastal ecology are expanding the geographic extent, frequency, magnitude, and species complexity'' of algal blooms throughout the world, increasing the threat of fish and shellfish poisonings, anoxia in marine nurseries, and of cholera. The World Health Organization and members of the medical profession have described the potential health effects of global climate change. They warn of the consequences of increased ultraviolet-B (UV-B) rays and of warming: the possible damage to agriculture and nutrition, and the impact on habitats which may alter the distribution of vector-borne and water-based infectious diseases. Algal growth due to increased nitrogen (N) and phosphorus (P) and warming are already affecting marine microflora and aquatic plants; and there is now clear evidence that marine organisms are a reservoir for enteric pathogens. The pattern of cholera in the Western Hemisphere suggests that environmental changes have already begun to influence the epidemiology of this infectious disease. 106 refs.

  20. Nucleomorphs: enslaved algal nuclei.

    PubMed

    Cavalier-Smith, T

    2002-12-01

    Nucleomorphs of cryptomonad and chlorarachnean algae are the relict, miniaturised nuclei of formerly independent red and green algae enslaved by separate eukaryote hosts over 500 million years ago. The complete 551 kb genome sequence of a cryptomonad nucleomorph confirms that cryptomonads are eukaryote-eukaryote chimeras and greatly illuminates the symbiogenetic event that created the kingdom Chromista and their alveolate protozoan sisters. Nucleomorph membranes may, like plasma membranes, be more enduring after secondary symbiogenesis than are their genomes. Partial sequences of chlorarachnean nucleomorphs indicate that genomic streamlining is limited by the mutational difficulty of removing useless introns. Nucleomorph miniaturisation emphasises that selection can dramatically reduce eukaryote genome size and eliminate most non-functional nuclear non-coding DNA. Given the differential scaling of nuclear and nucleomorph genomes with cell size, it follows that most non-coding nuclear DNA must have a bulk-sequence-independent function related to cell volume.

  1. Micronuclei in peripheral blood and bone marrow cells of mice exposed to 42 GHz electromagnetic millimeter waves.

    PubMed

    Vijayalaxmi; Logani, Mahendra K; Bhanushali, Ashok; Ziskin, Marvin C; Prihoda, Thomas J

    2004-03-01

    The genotoxic potential of 42.2 +/- 0.2 GHz electromagnetic millimeter-wave radiation was investigated in adult male BALB/c mice. The radiation was applied to the nasal region of the mice for 30 min/day for 3 consecutive days. The incident power density used was 31.5 +/- 5.0 mW/cm2. The peak specific absorption rate was calculated as 622 +/- 100 W/kg. Groups of mice that were injected with cyclophosphamide (15 mg/kg body weight), a drug used in the treatment of human malignancies, were also included to determine if millimeter-wave radiation exposure had any influence on drug-induced genotoxicity. Concurrent sham-exposed and untreated mice were used as controls. The extent of genotoxicity was assessed from the incidence of micronuclei in polychromatic erythrocytes of peripheral blood and bone marrow cells collected 24 h after treatment. The results indicated that the incidence of micronuclei in 2000 polychromatic erythrocytes was not significantly different among untreated, millimeter wave-exposed, and sham-exposed mice. The group mean incidences were 6.0 +/- 1.6, 5.1 +/- 1.5 and 5.1 +/- 1.3 in peripheral blood and 9.1 +/- 1.1, 9.3 +/- 1.6 and 9.1 +/- 1.6 in bone marrow cells, respectively. Mice that were injected with cyclophosphamide exhibited significantly increased numbers of micronuclei, 14.6 +/- 2.7 in peripheral blood and 21.3 +/- 3.9 in bone marrow cells (P< 0.0001). The drug-induced micronuclei were not significantly different in millimeter wave-exposed and sham-exposed mice; the mean incidences were 14.3 +/- 2.8 and 15.4 +/- 3.0 in peripheral blood and 23.5 +/- 2.3 and 22.1 +/- 2.5 in bone marrow cells, respectively. Thus there was no evidence for the induction of genotoxicity in the peripheral blood and bone marrow cells of mice exposed to electromagnetic millimeter-wave radiation. Also, millimeter-wave radiation exposure did not influence cyclophosphamide-induced micronuclei in either type of cells.

  2. Acute respiratory bronchiolitis: an ultrastructural and autoradiographic study of epithelial cell injury and renewal in rhesus monkeys exposed to ozone.

    PubMed Central

    Castleman, W. L.; Dungworth, D. L.; Schwartz, L. W.; Tyler, W. S.

    1980-01-01

    The pathogenesis of acute respiratory bronchiolitis was examined in rhesus monkeys exposed to 0.8 ppm ozone fpr 4--50 hours. Epithelial injury and renewal was qualitatively and quantitatively characterized by correlated techniques of scanning and transmission electron microscopy as well as by light-microscopic autoradiography following labeling with tritiated thymidine. Extensive degeneration and necrosis of Type 1 epithelial cells occurred on the respiratory bronchiolar wall during the initial 4--12 hours of exposure. Increased numbers of labeled epithelial cells were present in this region after 18 hours of exposure, and the highest labeling index (18% was measured after 50 hours of exposure. Most (67--80%) of the labeled cells and all the mitotic epithelial cells (22) observed ultrastructurally were cuboidal bronchiolar epithelial cells. Of the labeled epithelial cells, 20--33% were Type 2 epithelial cells. After 50 hours of exposure the respiratory bronchiolar epithelium was hyperplastic. The predominant inflammatory cell in respiratory bronchiolar exudate was the alveolar macrophage. Monkeys that were exposed for 50 hours and allowed to recover in unozonized air for 7 days had incomplete resolution of respiratory bronchiolar epithelial hyperplasia. The results indicate that Type 1 epithelial cells lining respiratory bronchioles are the cell type most sensitive to injury and that both cuboidal bronchiolar epithelial cells and Type 2 epithelial cells function as stem cells in epithelial renewal. Images Figure 16 Figure 17 Figure 18 Figure 19 Figure 20 Figure 21 Figure 22 Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 23 Figure 24 Figure 25 Figure 9 Figure 10 Figure 26 Figure 27 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 PMID:6767409

  3. Impact of harmful algal blooms on several Lake Erie drinking water treatment facilities; methodology considerations

    EPA Science Inventory

    The propagation of cyanbacterial cells and their toxins were investigated at seven drinking water treatment plants (DWTPs) on Lake Erie were investigated with regards to harmful algal bloom (HAB) toxin concentrations, water quality variations in treatment plant influents, and pr...

  4. Mechanism of Algal Aggregation by Bacillus sp. Strain RP1137

    PubMed Central

    Powell, Ryan J.

    2014-01-01

    Alga-derived biofuels are one of the best alternatives for economically replacing liquid fossil fuels with a fungible renewable energy source. Production of fuel from algae is technically feasible but not yet economically viable. Harvest of dilute algal biomass from the surrounding water remains one of the largest barriers to economic production of algal biofuel. We identified Bacillus sp. strain RP1137 in a previous study and showed that this strain can rapidly aggregate several biofuel-producing algae in a pH- and divalent-cation-dependent manner. In this study, we further characterized the mechanism of algal aggregation by RP1137. We show that aggregation of both algae and bacteria is optimal in the exponential phase of growth and that the density of ionizable residues on the RP1137 cell surface changes with growth stage. Aggregation likely occurs via charge neutralization with calcium ions at the cell surface of both algae and bacteria. We show that charge neutralization occurs at least in part through binding of calcium to negatively charged teichoic acid residues. The addition of calcium also renders both algae and bacteria more able to bind to hydrophobic beads, suggesting that aggregation may occur through hydrophobic interactions. Knowledge of the aggregation mechanism may enable engineering of RP1137 to obtain more efficient algal harvesting. PMID:24771029

  5. Development and optimization of biofilm based algal cultivation

    NASA Astrophysics Data System (ADS)

    Gross, Martin Anthony

    This dissertation describes research done on biofilm based algal cultivation systems. The system that was developed in this work is the revolving algal biofilm cultivation system (RAB). A raceway-retrofit, and a trough-based pilot-scale RAB system were developed and investigated. Each of the systems significantly outperformed a control raceway pond in side-by-side tests. Furthermore the RAB system was found to require significantly less water than the raceway pond based cultivation system. Lastly a TEA/LCA analysis was conducted to evaluate the economic and life cycle of the RAB cultivation system in comparison to raceway pond. It was found that the RAB system was able to grow algae at a lower cost and was shown to be profitable at a smaller scale than the raceway pond style of algal cultivation. Additionally the RAB system was projected to have lower GHG emissions, and better energy and water use efficiencies in comparison to a raceway pond system. Furthermore, fundamental research was conducted to identify the optimal material for algae to attach on. A total of 28 materials with a smooth surface were tested for initial cell colonization and it was found that the tetradecane contact angle of the materials had a good correlation with cell attachment. The effects of surface texture were evaluated using mesh materials (nylon, polypropylene, high density polyethylene, polyester, aluminum, and stainless steel) with openings ranging from 0.05--6.40 mm. It was found that both surface texture and material composition influence algal attachment.

  6. Mechanism of algal aggregation by Bacillus sp. strain RP1137.

    PubMed

    Powell, Ryan J; Hill, Russell T

    2014-07-01

    Alga-derived biofuels are one of the best alternatives for economically replacing liquid fossil fuels with a fungible renewable energy source. Production of fuel from algae is technically feasible but not yet economically viable. Harvest of dilute algal biomass from the surrounding water remains one of the largest barriers to economic production of algal biofuel. We identified Bacillus sp. strain RP1137 in a previous study and showed that this strain can rapidly aggregate several biofuel-producing algae in a pH- and divalent-cation-dependent manner. In this study, we further characterized the mechanism of algal aggregation by RP1137. We show that aggregation of both algae and bacteria is optimal in the exponential phase of growth and that the density of ionizable residues on the RP1137 cell surface changes with growth stage. Aggregation likely occurs via charge neutralization with calcium ions at the cell surface of both algae and bacteria. We show that charge neutralization occurs at least in part through binding of calcium to negatively charged teichoic acid residues. The addition of calcium also renders both algae and bacteria more able to bind to hydrophobic beads, suggesting that aggregation may occur through hydrophobic interactions. Knowledge of the aggregation mechanism may enable engineering of RP1137 to obtain more efficient algal harvesting.

  7. Controversial cytogenetic observations in mammalian somatic cells exposed to extremely low frequency electromagnetic radiation: a review and future research recommendations.

    PubMed

    Vijayalaxmi; Obe, Guenter

    2005-07-01

    During the years 1990-2003, a large number of investigations were conducted using animals, cultured rodent and human cells as well as freshly collected human blood lymphocytes to determine the genotoxic potential of exposure to nonionizing radiation emitted from extremely low frequency electromagnetic fields (EMF). Among the 63 peer reviewed scientific reports, the conclusions from 29 studies (46%) did not indicate increased damage to the genetic material, as assessed from DNA strand breaks, incidence of chromosomal aberrations (CA), micronuclei (MN), and sister chromatid exchanges (SCE), in EMF exposed cells as compared with sham exposed and/or unexposed cells, while those from 14 investigations (22%) have suggested an increase in such damage in EMF exposed cells. The observations from 20 other studies (32%) were inconclusive. This study reviews the investigations published in peer reviewed scientific journals during 1990-2003 and attempts to identify probable reason(s) for the conflicting results. Recommendations are made for future research to address some of the controversial observations.

  8. Differential Adaptive Response and Survival of Salmonella enterica Serovar Enteritidis Planktonic and Biofilm Cells Exposed to Benzalkonium Chloride▿

    PubMed Central

    Mangalappalli-Illathu, Anil K.; Vidović, Sinisa; Korber, Darren R.

    2008-01-01

    This study examined the adaptive response and survival of planktonic and biofilm phenotypes of Salmonella enterica serovar Enteritidis adapted to benzalkonium chloride (BC). Planktonic cells and biofilms were continuously exposed to 1 μg ml−1 of BC for 144 h. The proportion of BC-adapted biofilm cells able to survive a lethal BC treatment (30 μg ml−1) was significantly higher (4.6-fold) than that of BC-adapted planktonic cells. Similarly, there were 18.3-fold more survivors among the BC-adapted biofilm cells than among their nonadapted (i.e., without prior BC exposure) cell counterparts at the lethal BC concentration, and this value was significantly higher than the value for BC-adapted planktonic cells versus nonadapted cells (3.2-fold). A significantly higher (P < 0.05) proportion of surviving cells was noticed among BC-adapted biofilm cells relative to BC-adapted planktonic cells following a 10-min heat shock at 55°C. Fatty acid composition was significantly influenced by phenotype (planktonic cells or biofilm) and BC adaptation. Cell surface roughness of biofilm cells was also significantly greater (P < 0.05) than that of planktonic cells. Key proteins upregulated in BC-adapted planktonic and biofilm cells included CspA, TrxA, Tsf, YjgF, and a probable peroxidase, STY0440. Nine and 17 unique proteins were upregulated in BC-adapted planktonic and biofilm cells, respectively. These results suggest that enhanced biofilm-specific upregulation of 17 unique proteins, along with the increased expression of CspA, TrxA, Tsf, YjgF, and a probable peroxidase, phenotype-specific alterations in cell surface roughness, and a shift in fatty acid composition conferred enhanced survival to the BC-adapted biofilm cell population relative to their BC-adapted planktonic cell counterparts. PMID:18663028

  9. Phenotypic malignant changes and untargeted lipidomic analysis of long-term exposed prostate cancer cells to endocrine disruptors

    SciTech Connect

    Bedia, Carmen Dalmau, Núria Jaumot, Joaquim Tauler, Romà

    2015-07-15

    Endocrine disruptors (EDs) are a class of environmental toxic molecules able to interfere with the normal hormone metabolism. Numerous studies involve EDs exposure to initiation and development of cancers, including prostate cancer. In this work, three different EDs (aldrin, aroclor 1254 and chlorpyrifos (CPF)) were investigated as potential inducers of a malignant phenotype in DU145 prostate cancer cells after a chronic exposure. Epithelial to mesenchymal transition (EMT) induction, proliferation, migration, colony formation and release of metalloproteinase 2 (MMP-2) were analyzed in 50-day exposed cells to the selected EDs. As a result, aldrin and CPF exposure led to an EMT induction (loss of 16% and 14% of E-cadherin levels, respectively, compared to the unexposed cells). Aroclor and CPF presented an increased migration (134% and 126%, respectively), colony formation (204% and 144%, respectively) and MMP-2 release (137% in both cases) compared to the unexposed cells. An untargeted lipidomic analysis was performed to decipher the lipids involved in the observed transformations. As general results, aldrin exposure showed a global decrease in phospholipids and sphingolipids, and aroclor and CPF showed an increase of certain phospholipids, glycosphingolipids as well as a remarkable increase of some cardiolipin species. Furthermore, the three exposures resulted in an increase of some triglyceride species. In conclusion, some significant changes in lipids were identified and thus we postulate that some lipid compounds and lipid metabolic pathways could be involved in the acquisition of the malignant phenotype in exposed prostate cancer cells to the selected EDs. - Highlights: • Aldrin, aroclor and chlorpyrifos induced an aggressive phenotype in DU145 cells. • An untargeted lipidomic analysis has been performed on chronic exposed cells. • Lipidomic results showed changes in specific lipid species under chronic exposure. • These lipids may have a role in the

  10. Evaluation of cytotoxicity, morphological alterations and oxidative stress in Chinook salmon cells exposed to copper oxide nanoparticles.

    PubMed

    Srikanth, Koigoora; Pereira, Eduarda; Duarte, Armando C; Rao, Janapala Venkateswara

    2016-05-01

    The current study is aimed to study cytotoxicity and oxidative stress mediated changes induced by copper oxide nanoparticles (CuO NPs) in Chinook salmon cells (CHSE-214). To this end, a number of biochemical responses are evaluated in CHSE-214 cells which are as follows [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide] MTT, neutral red uptake (NRU), lactate dehydrogenase (LDH), protein carbonyl (PC), lipid peroxidation (LPO), oxidised glutathione (GSSG), reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione sulfo-transferase (GST), superoxide dismutase (SOD), catalase (CAT), 8-Hydroxy-2'-deoxyguanosine (8-OHdG) and reactive oxygen species (ROS), respectively. The 50% inhibition concentration (IC50) of CuO NPs to CHSE-214 cells after 24 h exposure was found to be 19.026 μg ml(-1). Viability of cells was reduced by CuO NPs, and the decrease was dose dependent as revealed by the MTT and NRU assay. CHSE-214 cells exposed to CuO NPs induced morphological changes. Initially, cells started to detach from the surface (12 h), followed by polyhedric, fusiform appearance (19 h) and finally the cells started to shrink. Later, the cells started losing their cellular contents leading to their death only after 24 h. LDH, PC, LPO, GSH, GPx, GST, SOD, CAT, 8-OHdG and ROS responses were seen significantly increased with the increase in the concentration of CuO NPs when compared to their respective controls. However, significant decrease in GSSG was perceptible in CHSE-214 cells exposed to CuO NPs in a dose-dependent manner. Our data demonstrated that CuO NPs induced cytotoxicity in CHSE-214 cells through the mediation of oxidative stress. The current study provides a baseline for the CuO NPs-mediated cytotoxic assessment in CHSE-214 cells for the future studies.

  11. LASER CAPTURE MICRODISSECTION AND GENE ARRAY ANALYSIS OF PALATAL EPITHELIAL AND MESENCHYMAL CELLS EXPOSED TO TCDD

    EPA Science Inventory

    Palatal shelves from embryos exposed on gestation day (GD) 12 to either retinoic acid (RA) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) contact but fail to fuse. It is of interest to know if diverse agents that induce clefting via the same etiology also activate the same biochem...

  12. Global Transcriptomic Analysis of Model Human Cell Lines Exposed to Surface-Modified Gold Nanoparticles: The Effect of Surface Chemistry

    PubMed Central

    Grzincic, E. M.; Yang, J. A.; Drnevich, J.; Falagan-Lotsch, P.; Murphy, C. J.

    2015-01-01

    Gold nanoparticles (Au NPs) are attractive for biomedical applications not only for their remarkable physical properties, but also for the ease of which their surface chemistry can be manipulated. Many applications involve functionalization of the Au NP surface in order to improve biocompatibility, attach targeting ligands or carry drugs. However, changes in cells exposed to Au NPs of different surface chemistries have been observed, and little is known about how Au NPs and their surface coatings may impact cellular gene expression. The gene expression of two model human cell lines, human dermal fibroblasts (HDF) and prostate cancer cells (PC3) was interrogated by microarray analysis of over 14,000 human genes. The cell lines were exposed to four differently functionalized Au NPs: citrate, poly(allylamine hydrochloride) (PAH), and lipid coatings combined with alkanethiols or PAH. Gene functional annotation categories and weighted gene correlation network analysis were used in order to connect gene expression changes to common cellular functions and to elucidate expression patterns between Au NP samples. Coated Au NPs affect genes implicated in proliferation, angiogenesis, and metabolism in HDF cells, and inflammation, angiogenesis, proliferation apoptosis regulation, survival and invasion in PC3 cells. Subtle changes in surface chemistry, such as the initial net charge, lability of the ligand, and underlying layers greatly influence the degree of expression change and the type of cellular pathway affected. PMID:25491924

  13. Mutagenic adaptive response to high-LET radiation in human lymphoblastoid cells exposed to X-rays.

    PubMed

    Varès, Guillaume; Wang, Bing; Tanaka, Kaoru; Kakimoto, Ayana; Eguchi-Kasai, Kyomi; Nenoi, Mitsuru

    2011-01-10

    The ability of cells to adapt low-dose or low-dose rate radiation is well known. High-LET radiation has unique characteristics, and the data concerning low doses effects and high-LET radiation remain fragmented. In this study, we assessed in vitro the ability of low doses of X-rays to induce an adaptive response (AR) to a subsequent challenging dose of heavy-ion radiation. Lymphoblastoid cells (TK6, AHH-1, NH32) were exposed to priming 0.02-0.1Gy X-rays, followed 6h later by challenging 1Gy heavy-ion radiation (carbon-ion: 20 and 40keV/μm, neon-ion: 150keV/μm). Pre-exposure of p53-competent cells resulted in decreased mutation frequencies at hypoxanthine-guanine phosphoribosyl transferase locus and different H2AX phosphorylation kinetics, as compared to cells exposed to challenging radiation alone. This phenomenon did not seem to be linked with cell cycle effects or radiation-induced apoptosis. Taken together, our results suggested the existence of an AR to mutagenic effects of heavy-ion radiation in lymphoblastoid cells and the involvement of double-strand break repair mechanisms.

  14. Cell viability, reactive oxygen species, apoptosis, and necrosis in myoblast cultures exposed to low-level infrared laser.

    PubMed

    Alexsandra da Silva Neto Trajano, Larissa; da Silva, Camila Luna; de Carvalho, Simone Nunes; Cortez, Erika; Mencalha, André Luiz; de Souza da Fonseca, Adenilson; Stumbo, Ana Carolina

    2016-07-01

    Low-level infrared laser is considered safe and effective for treatment of muscle injuries. However, the mechanism involved on beneficial effects of laser therapy are not understood. The aim was to evaluate cell viability, reactive oxygen species, apoptosis, and necrosis in myoblast cultures exposed to low-level infrared laser at therapeutic fluences. C2C12 myoblast cultures at different (2 and 10 %) fetal bovine serum (FBS) concentrations were exposed to low-level infrared laser (808 nm, 100 mW) at different fluences (10, 35, and 70 J/cm(2)) and evaluated after 24, 48, and 72 h. Cell viability was evaluated by WST-1 assay; reactive oxygen species (ROS), apoptosis, and necrosis were evaluated by flow cytometry. Cell viability was decreased atthe lowest FBS concentration. Laser exposure increased the cell viability in myoblast cultures at 2 % FBS after 48 and 72 h, but no significant increase in ROS was observed. Apoptosis was decreased at the higher fluence and necrosis was increased at lower fluence in myoblast cultures after 24 h of laser exposure at 2 % FBS. No laser-induced alterations were obtained at 10 % FBS. Results show that level of reactive oxygen species is not altered, at least to those evaluated in this study, but low-level infrared laser exposure affects cell viability, apoptosis, and necrosis in myoblast cultures depending on laser fluence and physiologic conditions of cells.

  15. Interleukins 2 and 12 produce significant recovery of cytotoxic function in dibutyltin-exposed human natural killer cells.

    PubMed

    Whalen, Margaret M; Walker, Latarchal; Loganathan, Bommanna G

    2002-02-01

    Cytotoxic function of human natural killer (NK) cells is modulated by a variety of cytokines. Interleukins (IL) 2, 12, 15, and 18 and Interferon gamma (IFNgamma) are potent stimulators of NK cell cytotoxicity. Butyltins (BTs) are used in a variety of consumer products and industrial applications. Dibutyltin (DBT) is found in plastic products, beverages stored in PVC pipes during manufacturing, and poultry products. BTs appear to increase the risk of cancer and viral infections in exposed individuals. Recently, we have demonstrated that the ability of NK cells to kill tumor cells is greatly diminished after a 1-h exposure to dibutyltin. This inhibition of tumor killing function continues even after removal of the compound. There is no significant recovery of NK cytotoxic function even when the cells are allowed to recover for 6 days. In the current study we examine the effects of NK-stimulatory cytokines on the ability of NK cells to recover from the inhibitory effects of a 1-h DBT treatment. Highly purified NK cells (>95% CD16(+)) or a lymphocyte preparation containing both T lymphocytes and NK cells were treated with 5 microM DBT and then allowed to recover for 24 h, 48 h, 4 days, and 6 days in DBT-free medium containing either no cytokine or a maximally stimulatory dose of several NK-stimulatory cytokines. Tumor killing function was tested using a radioactive chromium release assay. As seen in our previous studies there is no recovery of NK cell cytotoxic function even after a 6-day recovery period when no cytokine is present in the medium. However, there is significant recovery of NK cytotoxic function when IL2, IL12, or the combination of IL2 plus IL12 is present in the medium during the recovery period. The other cytokines tested (IL15, IL18, and IFNgamma) were unable to increase the cytotoxicity of DBT-exposed NK cells.

  16. Methods for removing contaminants from algal oil

    SciTech Connect

    Lupton, Francis Stephen

    2016-09-27

    Methods for removing contaminants from algal oil are provided. In an embodiment, a method comprises the steps of combining a sulfuric acid-aqueous solution that has a pH of about 1 or less with a contaminant-containing algal oil at treatment conditions effective to form an effluent. The effluent comprises a treated algal oil phase and contaminants in an acidic aqueous phase. The contaminants comprise metals, phosphorus, or combinations thereof. The acidic aqueous phase is removed from the effluent to form a contaminant-depleted algal oil.

  17. Signs of Müller cell gliotic response found in the retina of newts exposed to real and simulated microgravity

    NASA Astrophysics Data System (ADS)

    Grigoryan, E. N.; Anton, H. J.; Poplinskaya, V. A.; Aleinikova, K. S.; Domaratskaya, E. I.; Novikova, Y. P.; Almeida, E.

    2012-05-01

    The effects of real and simulated microgravity on the eye tissue regeneration of newts were investigated. For the first time changes in Müller glial cells in the retina of eyes regenerating after retinal detachment were detected in newts exposed to clinorotation. The cells divided, were hypertrophied, and their processes were thickened. Such changes suggested reactive gliosis and were more significant in animals exposed to rotation when compared with desk-top controls. Later experiments onboard the Russian biosatellite Bion-11 showed similar changes in the retinas that were regenerating in a two-week spaceflight. In the Bion-11 animals, GFAP, the major structural protein of retinal macroglial cells, was found to be upregulated. In a more recent experiment onboard Foton-M3 (2007), GFAP expression in retinas of space-flown, ground control (kept at 1 g), and basal control (sacrificed on launch day) newts was quantified, using microscopy, immunohistochemistry, and digital image analysis. A low level of immunoreactivity was observed in basal controls. In contrast, retinas of space-flown animals showed greater GFAP immunoreactivity associated with both an increased cell number and a higher thickness of intermediate filaments. This, in turn, was accompanied by up-regulation of stress protein (HSP90) and growth factor (FGF2) expressions. It can be postulated that such a response of Müller cells was to mitigate the retinal stress in newts exposed to microgravity. Taken together, the data suggest that the retinal population of macroglial cells could be sensitive to gravity changes and that in space it can react by enhancing its neuroprotective function.

  18. The dynamics of heterotrophic algal cultures.

    PubMed

    De la Hoz Siegler, H; Ben-Zvi, A; Burrell, R E; McCaffrey, W C

    2011-05-01

    In this work, the time varying characteristics of microalgal cultures are investigated. Microalgae are a promising source of biofuels and other valuable chemicals; a better understanding of their dynamic behavior is, however, required to facilitate process scale-up, optimization and control. Growth and oil production rates are evaluated as a function of carbon and nitrogen sources concentration. It is found that nitrogen has a major role in controlling the productivity of microalgae. Moreover, it is shown that there exists a nitrogen source concentration at which biomass and oil production can be maximized. A mathematical model that describes the effect of nitrogen and carbon source on growth and oil production is proposed. The model considers the uncoupling between nutrient uptake and growth, a characteristic of algal cells. Validity of the proposed model is tested on fed-batch cultures.

  19. Recent progress and future challenges in algal biofuel production

    PubMed Central

    Shurin, Jonathan B.; Burkart, Michael D.; Mayfield, Stephen P.

    2016-01-01

    Modern society is fueled by fossil energy produced millions of years ago by photosynthetic organisms. Cultivating contemporary photosynthetic producers to generate energy and capture carbon from the atmosphere is one potential approach to sustaining society without disrupting the climate. Algae, photosynthetic aquatic microorganisms, are the fastest growing primary producers in the world and can therefore produce more energy with less land, water, and nutrients than terrestrial plant crops. We review recent progress and challenges in developing bioenergy technology based on algae. A variety of high-value products in addition to biofuels can be harvested from algal biomass, and these may be key to developing algal biotechnology and realizing the commercial potential of these organisms. Aspects of algal biology that differentiate them from plants demand an integrative approach based on genetics, cell biology, ecology, and evolution. We call for a systems approach to research on algal biotechnology rooted in understanding their biology, from the level of genes to ecosystems, and integrating perspectives from physical, chemical, and social sciences to solve one of the most critical outstanding technological problems. PMID:27781084

  20. Increased Frequency of Spontaneous Neoplastic Transformation in Progeny of Bystander Cells from Cultures Exposed to Densely Ionizing Radiation

    PubMed Central

    Buonanno, Manuela; de Toledo, Sonia M.; Azzam, Edouard I.

    2011-01-01

    An increased risk of carcinogenesis caused by exposure to space radiation during prolonged space travel is a limiting factor for human space exploration. Typically, astronauts are exposed to low fluences of ionizing particles that target only a few cells in a tissue at any one time. The propagation of stressful effects from irradiated to neighboring bystander cells and their transmission to progeny cells would be of importance in estimates of the health risks of exposure to space radiation. With relevance to the risk of carcinogenesis, we investigated, in model C3H 10T½ mouse embryo fibroblasts (MEFs), modulation of the spontaneous frequency of neoplastic transformation in the progeny of bystander MEFs that had been in co-culture 10 population doublings earlier with MEFs exposed to moderate doses of densely ionizing iron ions (1 GeV/nucleon) or sparsely ionizing protons (1 GeV). An increase (P<0.05) in neoplastic transformation frequency, likely mediated by intercellular communication through gap junctions, was observed in the progeny of bystander cells that had been in co-culture with cells irradiated with iron ions, but not with protons. PMID:21738697

  1. Gene Expression Changes in Human Lung Cells Exposed to Arsenic, Chromium, Nickel or Vanadium Indicate the First Steps in Cancer

    PubMed Central

    Clancy, Hailey A.; Sun, Hong; Passantino, Lisa; Kluz, Thomas; Muñoz, Alexandra; Zavadil, Jiri; Costa, Max

    2013-01-01

    The complex process of carcinogenesis begins with transformation of a single cell to favor aberrant traits such as loss of contact inhibition and unregulated proliferation – features found in every cancer. Despite cancer’s widespread prevalence, the early events that initiate cancer remain elusive, and without knowledge of these events cancer prevention is difficult. Here we show that exposure to As, Cr, Ni, or Vanadium (V) promotes changes in gene expression that occur in conjunction with aberrant growth. We exposed immortalized human bronchial epithelial cells to one of four metals/metalloid for four to eight weeks and selected transformed clonal populations based upon anchorage independent growth of single cells in soft agar. We detected a metal-specific footprint of cancer-related gene expression that was consistent across multiple transformed clones. These gene expression changes persisted in the absence of the progenitor metal for numerous cell divisions. Our results show that even a brief exposure to a carcinogenic metal may cause many changes in gene expression in the exposed cells, and that from these many changes, the specific change(s) that each metal causes that initiate cancer likely arise. PMID:22714537

  2. Combined effect of predatory zooplankton and allelopathic aquatic macrophytes on algal suppression.

    PubMed

    Zuo, Shengpeng; Wan, Kun; Ma, Sumin

    2015-01-01

    The present study evaluated the combined effects of four typical predatory zooplankton and allelopathic aquatic macrophytes on algal control in a microcosm system. It would determine the effects of diverse species and biological restoration on the growth of harmful water-bloom microalgae in great lakes polluted by excess nutrients. It was found that the mixtures of each zooplankton and the floating plant Nymphoides peltatum had stronger inhibitory effects on harmful water-bloom microalgae than the individual species in clean or eutrophic water bodies. In addition, a community of four zooplankton types had a synergistic effect on algal inhibition. Algal suppression by the zooplankton community was enhanced significantly when the macrophyte was co-cultured in the microcosm. Furthermore, Chlorella pyrenoidosa was more susceptible than Microcystis aeruginosa when exposed to grazing by zooplankton and the allelopathic potential of the macrophyte. Algal inhibition was also weaker in eutrophic conditions compared with the control. These findings indicate that diverse species may enhance algal inhibition. Therefore, it is necessary to restore biological diversity and rebuild an ecologically balanced food chain or web to facilitate the control of harmful algal blooms in eutrophic lakes.

  3. Raman microspectroscopy based sensor of algal lipid unsaturation

    NASA Astrophysics Data System (ADS)

    Samek, Ota; Pilát, Zdeněk; Jonáš, Alexandr; Zemánek, Pavel; Šerý, Mojmír; Ježek, Jan; Bernatová, Silvie; Nedbal, Ladislav; Trtílek, Martin

    2011-05-01

    Raman spectroscopy is a powerful tool for chemical analysis. This technique can elucidate fundamental questions about the metabolic processes and intercellular variability on a single cell level. Therefore, Raman spectroscopy can significantly contribute to the study and use of microalgae in systems biology and biofuel technology. Raman spectroscopy can be combined with optical tweezers. We have employed microfluidic system to deliver the sampled microalgae to the Raman-tweezers. This instrument is able to measure chemical composition of cells and to track metabolic processes in vivo, in real-time and label-free making it possible to detect population variability in a wide array of traits. Moreover, employing an active sorting switch, cells can be separated depending on input parameters obtained from Raman spectra. We focus on algal lipids which are promising potential products for biofuel as well as for nutrition. Important parameter characterizing the algal lipids is the degree of unsaturation of the constituent fatty acids. We demonstrate the capacity of our Raman tweezers based sensor to sort cells according to the degree of unsaturation in lipid storage bodies of individual living algal cells.

  4. Synergistic cytotoxicity and DNA strand breaks in cells and plasmid DNA exposed to uranyl acetate and ultraviolet radiation.

    PubMed

    Wilson, Janice; Zuniga, Mary C; Yazzie, Filbert; Stearns, Diane M

    2015-04-01

    Depleted uranium (DU) has a chemical toxicity that is independent of its radioactivity. The purpose of this study was to explore the photoactivation of uranyl ion by ultraviolet (UV) radiation as a chemical mechanism of uranium genotoxicity. The ability of UVB (302 nm) and UVA (368 nm) radiation to photoactivate uranyl ion to produce single strand breaks was measured in pBR322 plasmid DNA, and the presence of adducts and apurinic/apyrimidinic sites that could be converted to single strand breaks by heat and piperidine was analyzed. Results showed that DNA lesions in plasmid DNA exposed to UVB- or UVA-activated DU were only slightly heat reactive, but were piperidine sensitive. The cytotoxicity of UVB-activated uranyl ion was measured in repair-proficient and repair-deficient Chinese hamster ovary cells and human keratinocyte HaCaT cells. The cytotoxicity of co-exposures of uranyl ion and UVB radiation was dependent on the order of exposure and was greater than co-exposures of arsenite and UVB radiation. Uranyl ion and UVB radiation were synergistically cytotoxic in cells, and cells exposed to photoactivated DU required different DNA repair pathways than cells exposed to non-photoactivated DU. This study contributes to our understanding of the DNA lesions formed by DU, as well as their repair. Results suggest that excitation of uranyl ion by UV radiation can provide a pathway for uranyl ion to be chemically genotoxic in populations with dermal exposures to uranium and UV radiation, which would make skin an overlooked target organ for uranium exposures.

  5. Mitochondrial-mediated apoptosis pathway in alveolar epithelial cells exposed to the metals in combustion-generated particulate matter.

    PubMed

    Visalli, Giuseppa; Baluce, Barbara; Bertuccio, Maria; Picerno, Isa; Di Pietro, Angela

    2015-01-01

    Previously a significant mitochondrial impairment was identified in alveolar epithelial cells exposed to metals adsorbed to combustion-generated particulate matter (PM). Due to the critical role of mitochondria in apoptosis, the aim of this study was to investigate the pro-apoptotic potential of metals present in oil fly ash (OFA). A549 cells were exposed to water-soluble components of an OFA sample, containing vanadium [V(IV)], iron [Fe(III)], and nickel [Ni(II)] (68.8, 110.4, and 18 μM, respectively). Experiments were also performed using individual metal solutions. Apoptosis was detected and the mitochondrial role was assessed by a caspase-9 inhibitor (Z-LEHD-FMK). To determine whether the presence of impaired mitochondria in unexposed daughter cells increased apoptosis, an in vitro model was developed that allowed determination of effects until the third cell generation. To specifically examine the toxicity of vanadium (V), that characterize the airborne pollutant examined in this study, p53involvement and metabolic impairment through changes in HIF-1α and Glut-1 expression were determined. OFA and individual metal solutions produced significant apoptosis in the progeny of exposed cells, triggering the intrinsic apoptosis pathway. In apoptosis induced by poorly genotoxic metal V, p53 did not play a significant role. However, V exposure increased nuclear translocation of HIF-1α and expression of the Glut-1 receptor, indicating metabolic impairment due to metal-induced mitochondrial dysfunction. Overall, these results improve our knowledge of the pathogenic role that airborne metals and in particular V exerted in respiratory epithelium.

  6. Synergistic cytotoxicity and DNA strand breaks in cells and plasmid DNA exposed to uranyl acetate and ultraviolet radiation

    PubMed Central

    Wilson, Janice; Zuniga, Mary C.; Yazzie, Filbert; Stearns, Diane M.

    2015-01-01

    Depleted uranium (DU) has a chemical toxicity that is independent of its radioactivity. The purpose of this study was to explore the photoactivation of uranyl ion by ultraviolet (UV) radiation as a chemical mechanism of uranium genotoxicity. The ability of UVB (302 nm) and UVA (368 nm) radiation to photoactivate uranyl ion to produce single strand breaks was measured in pBR322 plasmid DNA, and the presence of adducts and apurinic/apyrimidinic sites that could be converted to single strand breaks by heat and piperidine was analyzed. Results showed that DNA lesions in plasmid DNA exposed to UVB- or UVA-activated DU were only slightly heat reactive, but were piperidine sensitive. The cytotoxicity of UVB-activated uranyl ion was measured in repair-proficient and repair-deficient Chinese hamster ovary cells and human keratinocyte HaCaT cells. The cytotoxicity of co-exposures of uranyl ion and UVB radiation was dependent on the order of exposure and was greater than co-exposures of arsenite and UVB radiation. Uranyl ion and UVB radiation were synergistically cytotoxic in cells, and cells exposed to photoactivated DU required different DNA repair pathways than cells exposed to non-photoactivated DU. This study contributes to our understanding of the DNA lesions formed by DU, as well as their repair. Results suggest that excitation of uranyl ion by UV radiation can provide a pathway for uranyl ion to be chemically genotoxic in populations with dermal exposures to uranium and UV radiation, which would make skin an overlooked target organ for uranium exposures. PMID:24832689

  7. Pulmonary function and symptoms of Nigerian workers exposed to carbon black in dry cell battery and tire factories

    SciTech Connect

    Oleru, U.G.; Elegbeleye, O.O.; Enu, C.C.; Olumide, Y.M.

    1983-02-01

    The pulmonary function and symptoms of 125 workers exposed to carbon black in dry cell battery and tire manufacturing plants were investigated. There was no significant difference in the pulmonary function of the subjects in the two plants. There was good agreement in the symptoms reported in the two different factories: cough with phlegm production, tiredness, chest pain, catarrh, headache, and skin irritation. The symptoms also corroborate those reported in the few studies on the pulmonary effects of carbon black. The suspended particulate levels in the dry cell battery plant ranged from 25 to 34 mg/m/sup 3/ and the subjects with the highest probable exposure level had the most impaired pulmonary function. The pulmonary function of the exposed subjects was significantly lower than that of a control, nonindustrially exposed population. The drop in the lung function from the expected value per year of age was relatively constant for all the study subgroups but the drop per year of duration of employment was more severe in the earlier years of employment. This study has underscored the need for occupational health regulations in the industries of developing countries.

  8. Pulmonary function and symptoms of Nigerian workers exposed to Carbon black in dry cell battery and tire factories.

    PubMed

    Oleru, U G; Elegbeleye, O O; Enu, C C; Olumide, Y M

    1983-02-01

    The pulmonary function and symptoms of 125 workers exposed to carbon black in dry cell battery and tire manufacturing plants were investigated. There was no significant difference in the pulmonary function of the subjects in the two plants. There was good agreement in the symptoms reported in the two different factories: cough with phlegm production, tiredness, chest pain, catarrh, headache, and skin irritation. The symptoms also corroborate those reported in the few studies on the pulmonary effects of carbon black. The suspended particulate levels in the dry cell battery plant ranged from 25 to 34 mg/m3 and the subjects with the highest probable exposure level had the most impaired pulmonary function. The pulmonary function of the exposed subjects was significantly lower than that of a control, nonindustrially exposed population. The drop in the lung function from the expected value per year of age was relatively constant for all the study subgroups but the drop per year of duration of employment was more severe in the earlier years of employment. This study has underscored the need for occupational health regulations in the industries of developing countries.

  9. Differential gene expression in human hepatocyte cell lines exposed to the antiretroviral agent zidovudine.

    PubMed

    Fang, Jia-Long; Han, Tao; Wu, Qiangen; Beland, Frederick A; Chang, Ching-Wei; Guo, Lei; Fuscoe, James C

    2014-03-01

    Zidovudine (3'-azido-3'-deoxythymidine; AZT) is the most widely used nucleoside reverse transcriptase inhibitor for the treatment of AIDS patients and prevention of mother-to-child transmission of HIV-1. Previously, we demonstrated that AZT had significantly greater growth inhibitory effects upon the human liver carcinoma cell line HepG2 as compared to the immortalized human liver cell line THLE2. We have now used gene expression profiling to determine the molecular pathways associated with toxicity in both cell lines. HepG2 cells were incubated with 0, 2, 20, or 100 μM AZT for 2 weeks; THLE2 cells were treated with 0, 50, 500, or 2,500 μM AZT, concentrations that were equi-toxic to those used in the HepG2 cells. After the treatment, total RNA was isolated and subjected to microarray analysis. Global analysis of gene expression, with a false discovery rate ≤0.01 and a fold change ≥1.5, indicated that 6- to 70-fold more genes were differentially expressed in a significant concentration-dependent manner in HepG2 cells when compared to THLE2 cells. Comparative analysis indicated that 7 % of these genes were common to both cell lines. Among the common differentially expressed genes, 70 % changed in the same direction, most of which were associated with cell death and survival, cell cycle, cell growth and proliferation, and DNA replication, recombination, and repair. As determined by the uptake of [methyl-(3)H]AZT, the intracellular levels of total AZT were approximately twofold higher in THLE2 cells than in HepG2 cells. The expression of thymidine kinase 1 (TK1) and UDP-glucuronosyltransferase 2B7 (UGT2B7) genes that regulate the metabolic activation and deactivation of AZT, respectively, was increased in HepG2 cells but decreased in THLE2 cells after treatment with AZT. This differential response in AZT metabolism was confirmed by real-time PCR, western blotting, and/or enzymatic assays. These data indicate that molecular pathways involved with cell death and

  10. Immunostimulatory Activity of the Cytokine-Based Biologic, IRX-2, on Human Papillomavirus-Exposed Langerhans Cells

    PubMed Central

    Da Silva, Diane M.; Woodham, Andrew W.; Naylor, Paul H.; Egan, James E.; Berinstein, Neil L.

    2016-01-01

    Langerhans cells (LCs) are the antigen-presenting cells of the epithelial layer and are responsible for initiating immune responses against skin and mucosa-invading viruses. Human papillomavirus (HPV)-mediated suppression of LC function is a crucial mechanism of HPV immune evasion, which can lead to persistent infection and development of several human cancers, including cervical, anal, and head and neck cancers. The cell-derived cytokine-based biologic, IRX-2, consists of multiple well-defined cytokines and is broadly active on various immune cell subsets. In this study, we investigated primary human LC activation after exposure to HPV16, followed by treatment with IRX-2 in vitro, and evaluated their subsequent ability to induce HPV16-specific T cells. In contrast to its activity on dendritic cells, HPV16 alone is not sufficient to induce phenotypic and functional activation of LCs. However, IRX-2 induces a significant upregulation of antigen presentation and costimulatory molecules, T helper 1 (Th1)-associated cytokine release, and chemokine-directed migration of LCs pre-exposed to HPV16. Furthermore, LCs treated with IRX-2 after HPV16 exposure induced CD8+ T-cell responses against specific HLA-A*0201-binding HPV16 T-cell epitopes. The present study suggests that IRX-2 is an attractive immunomodulator for assisting the immune response in eradication of HPV-infected cells, thereby potentially preventing HPV-induced cancers. PMID:26653678

  11. Oxidative stress and apoptosis induction in human thyroid carcinoma cells exposed to the essential oil from Pistacia lentiscus aerial parts

    PubMed Central

    Catalani, Simona; Palma, Francesco; Battistelli, Serafina; Benedetti, Serena

    2017-01-01

    Background Essential oils from the aerial parts (leaves, twigs and berries) of Pistacia lentiscus (PLEO) have been well characterized for their antibacterial and anti-inflammatory properties; however, poor information exists on their potential anticancer activity. Methods Increasing concentrations of PLEO (0.01–0.1% v/v, 80–800 μg/ml) were administered to a wide variety of cultured cancer cells from breast, cervix, colon, liver, lung, prostate, and thyroid carcinomas. Fibroblasts were also included as healthy control cells. Cell viability was monitored by WST-8 assay up to 72 hours after PLEO administration. The intracellular formation of reactive oxygen species (ROS), the induction of apoptosis, and the enhancement of chemotherapeutic drug cytotoxicity by PLEO were further investigated in the most responsive cancer cell line. Results A dose-dependent reduction of tumor cell viability was observed upon PLEO exposure; while no cytotoxic effect was revealed in healthy fibroblasts. FTC-133 thyroid cancer cells were found to be the most sensitive cells to PLEO treatment; accordingly, an intracellular accumulation of ROS and an activation of both the extrinsic and intrinsic apoptotic pathways were evidenced in FTC-133 cells after PLEO administration. Furthermore, the cytotoxic effect of the antineoplastic drugs cisplatin, 5-fluorouracil and etoposide was enhanced in PLEO-exposed FTC-133 cells. Conclusion Taking into account its mode of action, PLEO might be considered as a promising source of natural antitumor agents which might have therapeutic potential in integrated oncology. PMID:28196126

  12. Modulation by Ethanol of Cigarette Smoke Clastogenicity in Cells of Adult Mice and of Transplacentally Exposed Fetuses

    PubMed Central

    Balansky, Roumen; La Maestra, Sebastiano; Micale, Rosanna T.; Iltcheva, Marietta; Kirov, Krassimir; De Flora, Silvio

    2016-01-01

    Cigarette smoke (CS) and ethanol (EtOH) are known to synergize in the causation of cancers of the upper aerodigestive tract and of the liver. Little is known about possible interactions between these agents in other organs. These premises prompted us to evaluate the clastogenic effects resulting from the inhalation for 3 weeks of mainstream CS and oral administration of EtOH, which were tested either individually or in combination in cells of adult BDF1 mice and their fetuses. CS exerted clastogenic effects in haematopoietic cells of adult male mice by increasing the frequency of micronucleated erythroid cells both in bone marrow and in peripheral blood as well as the frequency of micronucleated and polynucleated pulmonary alveolar macrophages. Likewise, exposure to CS of pregnant mice resulted in a clastogenic damage in maternal bone marrow cells and in the liver and peripheral blood of their fetuses. Under all experimental conditions, EtOH was consistently devoid of clastogenic effects when given alone. In adult mice, EtOH exhibited a mild stimulating effect on the clastogenicity of CS in haematopoietic cells, while an opposite effect was observed in the respiratory tract, where EtOH attenuated the cytogenetic alterations induced by CS in pulmonary alveolar macrophages. At variance with the mild synergism observed in haematopoietic cells of adult mice, EtOH inhibited the clastogenicity of CS in the liver and peripheral blood cells of transplacentally exposed fetuses. Therefore, the effects of EtOH in CS-exposed mice show different trends depending both on the life stage and on the cells analyzed. PMID:27907070

  13. Abnormal regulation of DNA replication and increased lethality in ataxia telangiectasia cells exposed to carcinogenic agents

    SciTech Connect

    Jaspers, N.G.; de Wit, J.; Regulski, M.R.; Bootsma, D.

    1982-01-01

    The effect of different carcinogenic agents on the rate of semiconservative DNA replication in normal and ataxia telangiectasis (AT) cells was investigated. The rate of DNA synthesis in all AT cell strains tested was depressed to a significantly lesser extent than in normal cells after exposure to X-rays under oxia or hypoxia or to bleomycin, agents to which AT cells are hypersensitive. In contrast, inhibition of DNA replication in normal human and AT cells was similar after treatment with some DNA-methylating agents or mitomycin C. Colony-forming ability of AT cells treated with these agents was not different from normal cells. Treatment with 4-nitroquinoline 1-oxide elicited a variable response in both AT and normal cell strains. In some strains, including those shown to be hypersensitive to the drug by other workers, the inhibition of DNA synthesis was more pronounced than in other cell strains, but no significant difference between AT and normal cells could be detected. The rejoining of DNA strand breaks induced by X-rays, measured by DNA elution techniques, occurred within l2 hr after treatment and could not be correlated with the difference in DNA synthesis inhibition in AT and normal cells. After low doses of X-rays, AT cells rejoined single-strand breaks slightly more slowly than did normal cells. The rate of DNA replication in X-irradiation AT and normal cells was not affected by nicotinamide, an inhibitor of poly(adenosine diphosphate ribose) synthesis. These data indicate that the diminished inhibition of DNA replication in carcinogen-treated AT cells (a) is a general characteristic of all AT cell strains, (b) correlates with AT cellular hypersensitivity, (c) is not directly caused by the bulk of the DNA strand breaks produced by carcinogenic agents, and (d) is not based on differences in the induction of poly(adenosine diphosphate ribose) synthesis between X-irradiated AT and normal cells.

  14. Adsorption of Nanoplastics on Algal Photosynthesis

    NASA Astrophysics Data System (ADS)

    Turner, James; Bhattacharya, Priyanka; Lin, Sijie; Ke, Pu Chun

    2010-03-01

    The rapid accumulation of disposed plastics in the environment, especially in the Pacific Ocean, has become a global concern in recent years. Photo, chemical and physical degradations constantly fragment these plastics into a wide array of macroscopic to microscopic particles. As a result, marine organisms such as algae may be exposed to plastic particles through ingestion, adsorption and other forms of uptake. Such interactions, currently little understood, could potentially impact on the health state of the entire food chain. Here we report on polystyrene-algae interaction and its impact on algal photosynthesis. We first investigated the adsorption of polystyrene beads (20 nm) on a cellulose film coated on a 96-well plate. We derived a supralinear increase of the adsorption with the beads concentration for both positively and negatively charged polystyrene beads, with a saturation observed for the negatively charged polystyrene beads of concentration above 1.6 mg/mL. Using a bicarbonate indicator we discovered decreased carbon dioxide depletion due to polystyrene-algae binding. Since polystyrene beads also mediated algae aggregation, nanoplastics may alternatively be harnessed for waste water treatment.

  15. Effect of amygdalin on the proliferation of hyperoxia-exposed type II alveolar epithelial cells isolated from premature rat.

    PubMed

    Zhu, Huaping; Chang, Liwen; Li, Wenbin; Liu, Hanchu

    2004-01-01

    The pathogenesis of hyperoxia lung injury and the mechanism of amygdalin on type 2 alveolar epithelial cells (AEC2) isolated from premature rat lungs in vitro were investigated. AEC2 were obtained by primary culture from 20-days fetal rat lung and hyperoxia-exposed cell model was established. Cell proliferating viability was examined by MTT assay after treatment of amygdalin at various concentrations. DNA content and the proliferating cell nuclear antigen (PCNA) protein expression of AEC2 were measured by using flow cytometry and immunocytochemistry respectively after 24 h of hyperoxia exposure or amygdalin treatment. The results showed that hyperoxia inhibited the proliferation and decreased PCNA protein expression in A-EC2 of premature rat in vitro. Amygdalin at the concentration range of 50-200 micromol/L stimulated the proliferation of AEC2 in a dose-dependent manner, however, 400 micromol/L amygdalin inhibited the proliferation of AEC2. Amygdalin at the concentration of 200 micromol/L played its best role in facilitating proliferation of AEC2s in vitro and could partially ameliorated the changes of proliferation in hyperoxia exposed AEC2 of premature rat. It has been suggested that hyperoxia inhibited the proliferation of AEC2s of premature rat, which may contribute to hyperoxia lung injury. Amygdalin may play partial protective role in hyperoxia-induced lung injury.

  16. Global transcriptomic analysis of model human cell lines exposed to surface-modified gold nanoparticles: the effect of surface chemistry

    NASA Astrophysics Data System (ADS)

    Grzincic, E. M.; Yang, J. A.; Drnevich, J.; Falagan-Lotsch, P.; Murphy, C. J.

    2015-01-01

    Gold nanoparticles (Au NPs) are attractive for biomedical applications not only for their remarkable physical properties, but also for the ease of which their surface chemistry can be manipulated. Many applications involve functionalization of the Au NP surface in order to improve biocompatibility, attach targeting ligands or carry drugs. However, changes in cells exposed to Au NPs of different surface chemistries have been observed, and little is known about how Au NPs and their surface coatings may impact cellular gene expression. The gene expression of two model human cell lines, human dermal fibroblasts (HDF) and prostate cancer cells (PC3) was interrogated by microarray analysis of over 14 000 human genes. The cell lines were exposed to four differently functionalized Au NPs: citrate, poly(allylamine hydrochloride) (PAH), and lipid coatings combined with alkanethiols or PAH. Gene functional annotation categories and weighted gene correlation network analysis were used in order to connect gene expression changes to common cellular functions and to elucidate expression patterns between Au NP samples. Coated Au NPs affect genes implicated in proliferation, angiogenesis, and metabolism in HDF cells, and inflammation, angiogenesis, proliferation apoptosis regulation, survival and invasion in PC3 cells. Subtle changes in surface chemistry, such as the initial net charge, lability of the ligand, and underlying layers greatly influence the degree of expression change and the type of cellular pathway affected.Gold nanoparticles (Au NPs) are attractive for biomedical applications not only for their remarkable physical properties, but also for the ease of which their surface chemistry can be manipulated. Many applications involve functionalization of the Au NP surface in order to improve biocompatibility, attach targeting ligands or carry drugs. However, changes in cells exposed to Au NPs of different surface chemistries have been observed, and little is known about how

  17. Transcriptional expression levels of cell stress marker genes in the Pacific oyster Crassostrea gigas exposed to acute thermal stress

    PubMed Central

    Farcy, Émilie; Voiseux, Claire; Lebel, Jean-Marc

    2008-01-01

    During the annual cycle, oysters are exposed to seasonal slow changes in temperature, but during emersion at low tide on sunny summer days, their internal temperature may rise rapidly, resulting in acute heat stress. We experimentally exposed oysters to a 1-h acute thermal stress and investigated the transcriptional expression level of some genes involved in cell stress defence mechanisms, including chaperone proteins (heat shock proteins Hsp70, Hsp72 and Hsp90 (HSP)), regulation of oxidative stress (Cu-Zn superoxide dismutase, metallothionein (MT)), cell detoxification (glutathione S-transferase sigma, cytochrome P450 and multidrug resistance (MDR1)) and regulation of the cell cycle (p53). Gene mRNA levels were quantified by reverse transcription-quantitative polymerase chain reaction and expressed as their ratio to actin mRNA, used as a reference. Of the nine genes studied, HSP, MT and MDR1 mRNA levels increased in response to thermal stress. We compared the responses of oysters exposed to acute heat shock in summer and winter and observed differences in terms of magnitude and kinetics. A larger increase was observed in September, with recovery within 48 h, whereas in March, the increase was smaller and lasted more than 2 days. The results were also compared with data obtained from the natural environment. Though the functional molecule is the protein and information at the mRNA level only has limitations, the potential use of mRNAs coding for cell stress defence proteins as early sensitive biomarkers is discussed. PMID:19002605

  18. Gene expression profiling and pathway analysis of human bronchial epithelial cells exposed to airborne particulate matter collected from Saudi Arabia

    SciTech Connect

    Sun, Hong; Shamy, Magdy; Kluz, Thomas; Muñoz, Alexandra B.; Zhong, Mianhua; Laulicht, Freda; Alghamdi, Mansour A.; Khoder, Mamdouh I.; Chen, Lung-Chi; Costa, Max

    2012-12-01

    Epidemiological studies have established a positive correlation between human mortality and increased concentration of airborne particulate matters (PM). However, the mechanisms underlying PM related human diseases, as well as the molecules and pathways mediating the cellular response to PM, are not fully understood. This study aims to investigate the global gene expression changes in human cells exposed to PM{sub 10} and to identify genes and pathways that may contribute to PM related adverse health effects. Human bronchial epithelial cells were exposed to PM{sub 10} collected from Saudi Arabia for 1 or 4 days, and whole transcript expression was profiled using the GeneChip human gene 1.0 ST array. A total of 140 and 230 genes were identified that significantly changed more than 1.5 fold after PM{sub 10} exposure for 1 or 4 days, respectively. Ingenuity Pathway Analysis revealed that different exposure durations triggered distinct pathways. Genes involved in NRF2-mediated response to oxidative stress were up-regulated after 1 day exposure. In contrast, cells exposed for 4 days exhibited significant changes in genes related to cholesterol and lipid synthesis pathways. These observed changes in cellular oxidative stress and lipid synthesis might contribute to PM related respiratory and cardiovascular disease. -- Highlights: ► PM exposure modulated gene expression and associated pathways in BEAS-2B cells. ► One-day exposure to PM induced genes involved in responding to oxidative stress. ► 4-day exposure to PM changed genes associated to cholesterol and lipid synthesis.

  19. Morphologic, biochemical, and cytogenetic studies of bone marrow and circulating blood cells in painters exposed to ethylene glycol ethers.

    PubMed

    Cullen, M R; Solomon, L R; Pace, P E; Buckley, P; Duffy, T P; McPhedran, P; Kelsey, K T; Redlich, C A

    1992-10-01

    In a previous cross-sectional survey, up to 15% of shipyard painters were found to have mild anemia or granulocytopenia, mostly acquired since employment. Environmental studies had suggested a possible etiologic role for ethylene glycol ethers, solvents to which the men were heavily exposed and which have established myelotoxic potential. To exclude alternative hypotheses, examine possible common patterns of injury, and identify potential risk factors and markers for such an effect, the affected painters were further studied. The painters were matched with two groups of controls: exposed painters without evidence of hematologic abnormality on the previous survey and unexposed controls. Altogether 25 subjects were studied by histopathologic examination of bone marrow, cytogenetic studies of marrow cells, and peripheral lymphocytes and peripheral red cell studies of membrane and metabolic function. Except for an unexpected finding of a race-associated effect on marrow histology, insignificant differences were seen among the groups in terms of marrow morphology and cellularity, stem cell growth kinetics, and marrow or peripheral cytogenetics. Two metabolic abnormalities of peripheral red cells related to exposure or clinical status of the subjects were found. Pyruvate kinase, an established marker of acquired myelodysplasia, was significantly depressed in the subjects with previously abnormal counts. Although reduced glutathione levels and holoenzyme activities of glutathione reductase (GSHR) did not differ among groups, exposed subjects had decreased saturation of GSHR with flavin adenine dinucleotide which could be restored in vitro, suggesting riboflavin deficiency or impaired riboflavin metabolism. Thus, although a unique pattern of bone marrow injury by histologic or genetic assay attributable to ethylene glycol ethers was not defined, biochemical effects of possible mechanistic importance were identified. The relevance of these findings as subclinical disease

  20. Algal Bloom Detection from HICO

    NASA Astrophysics Data System (ADS)

    Amin, Ruhul; Gould, Richard

    2014-05-01

    Ocean color satellites provide daily, global views of marine bio-optical properties in the upper ocean at various spatial scales. The most productive area of the global ocean is the coastal zone which is heavily impacted by urban and agricultural runoff, transportation, recreation, and oil and gas production. In recent years, harmful algal blooms (HABs) have become one of the serious environmental problems in the coastal areas on a global scale. The global nature of the problem has expanded in its frequency, severity, and extent over the last several decades. Human activities and population increases have contributed to an increase in various toxic and noxious algal species in the coastal regions worldwide. Eutrophication in estuaries and coastal waters is believed to be the major factor causing HABs. In this study, we assess the applicability of the Red Band Difference (RBD) HAB detection algorithm on data from the Hyperspectral Imager for the Coastal Ocean (HICO). Our preliminary results show that due to various uncertainties such as atmospheric correction, calibration and possibly also the relatively low signal-to-noise ratio of HICO for fluorescence detection, it is difficult to extract the fluorescence portion of the reflectance spectrum that RBD uses for bloom detection. We propose an improved bloom detection technique for HICO using red and NIR bands. Our results are validated using other space-borne and ground based measurements.

  1. Friend leukemia virus transformed cells exposed to microgravity in the presence of DMSO (7-IML-1)

    NASA Technical Reports Server (NTRS)

    Cogoli, Augusto

    1992-01-01

    The purpose of this experiment is to study the adaptation of living cells to microgravity. The in vitro transformation of Friend cells by Dimethylsufoxide (DMSO) is a good model for the study of cell differentiation and protein biosynthesis. Cultures of cells will be prepared shortly before launch. Once in space, transformation will be induced by injection of DMSO. One set of cultures will be chemically fixed with glutaraldehyde for electron microscope investigations; another set will be preserved for determining the amount of hemogloben produced and the extent of cell proliferation.

  2. NREL Algal Biofuels Projects and Partnerships

    SciTech Connect

    2016-10-01

    This fact sheet highlights several algal biofuels research and development projects focused on improving the economics of the algal biofuels production process. These projects should serve as a foundation for the research efforts toward algae as a source of fuels and other chemicals.

  3. Process for selection of Oxygen-tolerant algal mutants that produce H.sub.2

    DOEpatents

    Ghirardi, Maria L.; Seibert, Michael

    1999-01-01

    A process for selection of oxygen-tolerant, H.sub.2 -producing algal mutant cells comprising: (a) growing algal cells photoautotrophically under fluorescent light to mid log phase; (b) inducing algal cells grown photoautrophically under fluorescent light to mid log phase in step (a) anaerobically by (1) resuspending the cells in a buffer solution and making said suspension anaerobic with an inert gas; (2) incubating the suspension in the absence of light at ambient temperature; (c) treating the cells from step (b) with metronidazole, sodium azide, and added oxygen to controlled concentrations in the presence of white light. (d) washing off metronidazole and sodium azide to obtain final cell suspension; (e) plating said final cell suspension on a minimal medium and incubating in light at a temperature sufficient to enable colonies to appear; (f) counting the number of colonies to determine the percent of mutant survivors; and (g) testing survivors to identify oxygen-tolerant H.sub.2 -producing mutants.

  4. Ultrastructural changes in hepatic sinusoidal endothelial cells acutely exposed to colloidal iron.

    PubMed

    Bassett, Mark L; Dahlstrom, Jane E; Taylor, Matthew C; Koina, Mark E; Maxwell, Lesley; Francis, Douglas; Jain, Sanjiv; McLean, Allan J

    2003-07-01

    Hepatic sinusoidal endothelial cells form an important interface between the vascular system, represented by the sinusoids, and the space of Disse that surrounds the hepatocyte microvilli. This study aimed to assess the light microscopic and ultrastructural effects of acute exposure of hepatic sinusoidal endothelial cells to colloidal iron by injection of rats with iron polymaltose. Eight minutes after a single intravenous injection of iron polymaltose sinusoidal endothelial cells showed defenestration, and thickening and layering as assessed by transmission electron microscopy. Kupffer cells and stellate cells appeared activated. These changes were not observed in control animals, experiments using equivalent doses of maltose, or experiments using colloidal carbon except for Kupffer cell activation due to colloidal carbon. No significant light microscopic changes were seen in study or control animals. The findings indicate that acute exposure to colloidal iron causes changes in hepatic sinusoidal endothelial cells, stellate cells and Kupffer cells. This may be the result of a direct toxic effect of iron or increased production of reactive oxygen species. These observations suggest a possible mechanism for defenestration of sinusoidal endothelial cells in ageing and in disease states.

  5. Metabolomics reveals metabolic changes in male reproductive cells exposed to thirdhand smoke

    NASA Astrophysics Data System (ADS)

    Xu, Bo; Chen, Minjian; Yao, Mengmeng; Ji, Xiaoli; Mao, Zhilei; Tang, Wei; Qiao, Shanlei; Schick, Suzaynn F.; Mao, Jian-Hua; Hang, Bo; Xia, Yankai

    2015-10-01

    Thirdhand smoke (THS) is a new term for the toxins in cigarette smoke that linger in the environment long after the cigarettes are extinguished. The effects of THS exposure on male reproduction have not yet been studied. In this study, metabolic changes in male germ cell lines (GC-2 and TM-4) were analyzed after THS treatment for 24 h. THS-loaded chromatography paper samples were generated in a laboratory chamber system and extracted in DMEM. At a paper: DMEM ratio of 50 μg/ml, cell viability in both cell lines was normal, as measured by the MTT assay and markers of cytotoxicity, cell cycle, apoptosis and ROS production were normal as measured by quantitative immunofluorescence. Metabolomic analysis was performed on methanol extracts of GC-2 and TM-4 cells. Glutathione metabolism in GC-2 cells, and nucleic acid and ammonia metabolism in TM-4 cells, was changed significantly by THS treatment. RT-PCR analyses of mRNA for enzyme genes Gss and Ggt in GC-2 cells, and TK, SMS and Glna in TM-4 cells reinforced these findings, showing changes in the levels of enzymes involved in the relevant pathways. In conclusion, exposure to THS at very low concentrations caused distinct metabolic changes in two different types of male reproductive cell lines.

  6. Metabolomics reveals metabolic changes in male reproductive cells exposed to thirdhand smoke

    PubMed Central

    Xu, Bo; Chen, Minjian; Yao, Mengmeng; Ji, Xiaoli; Mao, Zhilei; Tang, Wei; Qiao, Shanlei; Schick, Suzaynn F.; Mao, Jian-Hua; Hang, Bo; Xia, Yankai

    2015-01-01

    Thirdhand smoke (THS) is a new term for the toxins in cigarette smoke that linger in the environment long after the cigarettes are extinguished. The effects of THS exposure on male reproduction have not yet been studied. In this study, metabolic changes in male germ cell lines (GC-2 and TM-4) were analyzed after THS treatment for 24 h. THS-loaded chromatography paper samples were generated in a laboratory chamber system and extracted in DMEM. At a paper: DMEM ratio of 50 μg/ml, cell viability in both cell lines was normal, as measured by the MTT assay and markers of cytotoxicity, cell cycle, apoptosis and ROS production were normal as measured by quantitative immunofluorescence. Metabolomic analysis was performed on methanol extracts of GC-2 and TM-4 cells. Glutathione metabolism in GC-2 cells, and nucleic acid and ammonia metabolism in TM-4 cells, was changed significantly by THS treatment. RT-PCR analyses of mRNA for enzyme genes Gss and Ggt in GC-2 cells, and TK, SMS and Glna in TM-4 cells reinforced these findings, showing changes in the levels of enzymes involved in the relevant pathways. In conclusion, exposure to THS at very low concentrations caused distinct metabolic changes in two different types of male reproductive cell lines. PMID:26489853

  7. Morphological alterations of Vero cell exposed to coplanar PCB 126 and noncoplanar PCB 153.

    PubMed

    Shen, Kaili; Shen, Chaofeng; Chen, Lei; Chen, Xincai; Chen, Yingxu

    2012-01-01

    Polychlorinated biphenyls (PCBs) are widespread, persistent environmental contaminants that display a complex spectrum of toxicological properties. Exposure to PCBs has been associated with morphological anomalies in cell cultures. However, most mechanistic studies of PCBs' toxic activity have been focused on coplanar congeners. It is of importance to determine whether PCB treatment would influence cell configuration and whether these changes would depend on the structural characteristics of PCBs. In this study, we investigated cell morphological alteration in Vero cell cultures after exposure to coplanar PCB 126 and noncoplanar PCB 153. The survival of Vero cells was measured through the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) test. Cytotoxicity results suggested that PCB congeners had a toxic, antiproliferative effect on Vero cells. Morphological studies described structural modifications and provided evidence that apoptosis might be the main cell death pathway in PCB 153-treated cells. The comparison between PCB 126 and PCB 153 indicated that the cell death mechanisms involved in coplanar or noncoplanar PCB congener exposure were different in Vero cells.

  8. Metabolomics reveals metabolic changes in male reproductive cells exposed to thirdhand smoke

    SciTech Connect

    Xu, Bo; Chen, Minjian; Yao, Mengmeng; Ji, Xiaoli; Mao, Zhilei; Tang, Wei; Qiao, Shanlei; Schick, Suzaynn F.; Mao, Jian-Hua; Hang, Bo; Xia, Yankai

    2015-10-22

    Thirdhand smoke (THS) is a new term for the toxins in cigarette smoke that linger in the environment long after the cigarettes are extinguished. The effects of THS exposure on male reproduction have not yet been studied. In this study, metabolic changes in male germ cell lines (GC-2 and TM-4) were analyzed after THS treatment for 24 h. THS-loaded chromatography paper samples were generated in a laboratory chamber system and extracted in DMEM. At a paper: DMEM ratio of 50 μg/ml, cell viability in both cell lines was normal, as measured by the MTT assay and markers of cytotoxicity, cell cycle, apoptosis and ROS production were normal as measured by quantitative immunofluorescence. Metabolomic analysis was performed on methanol extracts of GC-2 and TM-4 cells. Furthermore, glutathione metabolism in GC-2 cells, and nucleic acid and ammonia metabolism in TM-4 cells, was changed significantly by THS treatment. RT-PCR analyses of mRNA for enzyme genes Gss and Ggt in GC-2 cells, and TK, SMS and Glna in TM-4 cells reinforced these findings, showing changes in the levels of enzymes involved in the relevant pathways. In conclusion, exposure to THS at very low concentrations caused distinct metabolic changes in two different types of male reproductive cell lines.

  9. Cadmium overkill: autophagy, apoptosis and necrosis signalling in endothelial cells exposed to cadmium.

    PubMed

    Messner, Barbara; Türkcan, Adrian; Ploner, Christian; Laufer, Günther; Bernhard, David

    2016-04-01

    Apoptosis, necrosis, or autophagy-it is the mode of cell demise that defines the response of surrounding cells and organs. In case of one of the most toxic substances known to date, cadmium (Cd), and despite a large number of studies, the mode of cell death induced is still unclear. As there exists conflicting data as to which cell death mode is induced by Cd both across various cell types and within a single one, we chose to analyse Cd-induced cell death in primary human endothelial cells by investigating all possibilities that a cell faces in undergoing cell death. Our results indicate that Cd-induced death signalling starts with the causation of DNA damage and a cytosolic calcium flux. These two events lead to an apoptosis signalling-related mitochondrial membrane depolarisation and a classical DNA damage response. Simultaneously, autophagy signalling such as ER stress and phagosome formation is initiated. Importantly, we also observed lysosomal membrane permeabilization. It is the integration of all signals that results in DNA degradation and a disruption of the plasma membrane. Our data thus suggest that Cd causes the activation of multiple death signals in parallel. The genotype (for example, p53 positive or negative) as well as other factors may determine the initiation and rate of individual death signals. Differences in the signal mix and speed may explain the differing results recorded as to the Cd-induced mode of cell death thus far. In human endothelial cells it is the sum of most if not all of these signals that determine the mode of Cd-induced cell death: programmed necrosis.

  10. Constraints to commercialization of algal fuels.

    PubMed

    Chisti, Yusuf

    2013-09-10

    Production of algal crude oil has been achieved in various pilot scale facilities, but whether algal fuels can be produced in sufficient quantity to meaningfully displace petroleum fuels, has been largely overlooked. Limitations to commercialization of algal fuels need to be understood and addressed for any future commercialization. This review identifies the major constraints to commercialization of transport fuels from microalgae. Algae derived fuels are expensive compared to petroleum derived fuels, but this could change. Unfortunately, improved economics of production are not sufficient for an environmentally sustainable production, or its large scale feasibility. A low-cost point supply of concentrated carbon dioxide colocated with the other essential resources is necessary for producing algal fuels. An insufficiency of concentrated carbon dioxide is actually a major impediment to any substantial production of algal fuels. Sustainability of production requires the development of an ability to almost fully recycle the phosphorous and nitrogen nutrients that are necessary for algae culture. Development of a nitrogen biofixation ability to support production of algal fuels ought to be an important long term objective. At sufficiently large scale, a limited supply of freshwater will pose a significant limitation to production even if marine algae are used. Processes for recovering energy from the algal biomass left after the extraction of oil, are required for achieving a net positive energy balance in the algal fuel oil. The near term outlook for widespread use of algal fuels appears bleak, but fuels for niche applications such as in aviation may be likely in the medium term. Genetic and metabolic engineering of microalgae to boost production of fuel oil and ease its recovery, are essential for commercialization of algal fuels. Algae will need to be genetically modified for improved photosynthetic efficiency in the long term.

  11. ATP Release from Human Airway Epithelial Cells Exposed to Staphylococcus aureus Alpha-Toxin

    PubMed Central

    Baaske, Romina; Richter, Mandy; Möller, Nils; Ziesemer, Sabine; Eiffler, Ina; Müller, Christian; Hildebrandt, Jan-Peter

    2016-01-01

    Airway epithelial cells reduce cytosolic ATP content in response to treatment with S. aureus alpha-toxin (hemolysin A, Hla). This study was undertaken to investigate whether this is due to attenuated ATP generation or to release of ATP from the cytosol and extracellular ATP degradation by ecto-enzymes. Exposure of cells to rHla did result in mitochondrial calcium uptake and a moderate decline in mitochondrial membrane potential, indicating that ATP regeneration may have been attenuated. In addition, ATP may have left the cells through transmembrane pores formed by the toxin or through endogenous release channels (e.g., pannexins) activated by cellular stress imposed on the cells by toxin exposure. Exposure of cells to an alpha-toxin mutant (H35L), which attaches to the host cell membrane but does not form transmembrane pores, did not induce ATP release from the cells. The Hla-mediated ATP-release was completely blocked by IB201, a cyclodextrin-inhibitor of the alpha-toxin pore, but was not at all affected by inhibitors of pannexin channels. These results indicate that, while exposure of cells to rHla may somewhat reduce ATP production and cellular ATP content, a portion of the remaining ATP is released to the extracellular space and degraded by ecto-enzymes. The release of ATP from the cells may occur directly through the transmembrane pores formed by alpha-toxin. PMID:27929417

  12. Metabolomics reveals metabolic changes in male reproductive cells exposed to thirdhand smoke

    DOE PAGES

    Xu, Bo; Chen, Minjian; Yao, Mengmeng; ...

    2015-10-22

    Thirdhand smoke (THS) is a new term for the toxins in cigarette smoke that linger in the environment long after the cigarettes are extinguished. The effects of THS exposure on male reproduction have not yet been studied. In this study, metabolic changes in male germ cell lines (GC-2 and TM-4) were analyzed after THS treatment for 24 h. THS-loaded chromatography paper samples were generated in a laboratory chamber system and extracted in DMEM. At a paper: DMEM ratio of 50 μg/ml, cell viability in both cell lines was normal, as measured by the MTT assay and markers of cytotoxicity, cellmore » cycle, apoptosis and ROS production were normal as measured by quantitative immunofluorescence. Metabolomic analysis was performed on methanol extracts of GC-2 and TM-4 cells. Furthermore, glutathione metabolism in GC-2 cells, and nucleic acid and ammonia metabolism in TM-4 cells, was changed significantly by THS treatment. RT-PCR analyses of mRNA for enzyme genes Gss and Ggt in GC-2 cells, and TK, SMS and Glna in TM-4 cells reinforced these findings, showing changes in the levels of enzymes involved in the relevant pathways. In conclusion, exposure to THS at very low concentrations caused distinct metabolic changes in two different types of male reproductive cell lines.« less

  13. Enhancement of B cell and monocyte populations in rats exposed to chlorpheniramine.

    PubMed

    Jung, Kyung-Jin; Choi, Woo-Hyuck; Park, Shin-Young; Lee, Sang-Hoon; Yoo, Jin-San; Koh, Woo Suk

    2012-12-01

    Chlorpheniramine is an anti-histamine agent on IgE-mediated inflammation. In order to investigate the immunomodulatory effects of chlorpheniramine, we assessed the changes of peripheral mononuclear cell populations and other general clinical parameters, including hematology and clinical chemistry, following chlorpheniramine administration in rats. Since prednisolone is commonly co-prescribed with anti-histamine in many hypersensitive reactions, we also examined the changes to compare the results after the prednisolone administration. Chlorpheniramine (50, 100 and 200 μg/kg) and prednisolone (1, 2 and 4 mg/kg) were intramuscularly administered to female Sprague-Dawley (SD) rats 3 times, at intervals of 1 week. Except the clinical signs, such as stiffness and abnormal gait due to the local toxicity at injection sites, no other significant changes in body weights, urinalysis, and macroscopic examination were noted in the animals given chlorpheniramine. On the other hand, white blood cells, especially B cells and monocytes, showed a dose-dependent increase in the chlorpheniramine-treated animals; whereas, the numbers of both B and T cells (helper T and cytotoxic T, NKT cells) were decreased in the prednisolone-treated animals. Taken together, these results suggest that chloropheniramine administration enhances white blood cells in the peripheral blood, mostly due to increases of the B cells and monocytes, but no T cells and NK cells.

  14. Chrondrogenesis in micromass cultures of embryonic mouse limb mesenchymal cells exposed to microgravity (7-IML-1)

    NASA Technical Reports Server (NTRS)

    Duke, Jackie

    1992-01-01

    A basic question of space biology is whether changes in gravity are perceived at the cellular level. Previous studies with a variety of cells have shown that this is the case, but to date the response of skeletal cells has not been examined, even though the skeleton is sensitive to gravitational changes. The objective of the CELLS Experiment is to examine the effect of microgravity in vitro on a skeletal cell known to be sensitive to gravitational changes both in vivo and in vitro - the mammalian chondrocyte. Various aspects of the experiment are discussed.

  15. In vitro response of retinal pigment epithelial cells exposed to chitosan materials prepared with different cross-linkers.

    PubMed

    Lai, Jui-Yang; Li, Ya-Ting; Wang, Tsu-Pin

    2010-01-01

    The interaction between cells and biopolymers is the evaluation indicator of the biocompatibility of materials. The purpose of this work was to examine the responses of retinal pigment epithelial (RPE) cells to genipin (GP) or glutaraldehyde (GTA) cross-linked chitosan by means of cell viability assays, cytokine expression analyses, and apoptosis assays. Evaluations of non-cross-linked chitosan were conducted simultaneously for comparison. Both GP and GTA treated samples with the same extent of cross-linking (around 80%) were prepared by varying cross-linking time. Our results showed that GP cross-linking was carried out by either radical polymerization of the monomers or S(N)2 nucleophilic substitution reaction involving the replacement of the ester group on the monomer with a secondary amide linkage. On the other hand, GTA could react with free amino groups of chitosan, leading to the formation of either the Schiff bases or the Michael-type adducts with terminal aldehydes. The biocompatibility of non-cross-linked chitosan membranes was demonstrated by the absence of any signs of toxicity or inflammation reaction. The present study showed that the ARPE-19 cells exposed to GTA cross-linked chitosan membranes had significantly higher cytotoxicity, interleukin-6 levels, and number of TUNEL-positive nuclei than did those exposed to GP treated samples. In addition, the materials modified with GTA trigger apoptosis at an early stage and may induce toxicity in the RPE cells later. The findings suggest that while the chitosan molecules bridged by GP are satisfactorily cytocompatible, the counterparts treated by GTA do not seem to be tolerated. In terms of material safety, the GP cross-linked chitosan may be compatible with human RPE cells and may have a potential application as delivery carriers in the treatment of posterior segment diseases.

  16. An Inactivated Antibiotic-Exposed Whole-Cell Vaccine Enhances Bactericidal Activities Against Multidrug-Resistant Acinetobacter baumannii

    PubMed Central

    Shu, Meng-Hooi; MatRahim, NorAziyah; NorAmdan, NurAsyura; Pang, Sui-Ping; Hashim, Sharina H.; Phoon, Wai-Hong; AbuBakar, Sazaly

    2016-01-01

    Vaccination may be an alternative treatment for infection with multidrug-resistance (MDR) Acinetobacter baumannii. The study reported here evaluated the bactericidal antibody responses following immunization of mice using an inactivated whole-cell vaccine derived from antibiotic-exposed MDR A. baumannii (I-M28-47-114). Mice inoculated with I-M28-47 (non-antibiotic-exposed control) and I-M28-47-114 showed a high IgG antibody response by day 5 post-inoculation. Sera from mice inoculated with I-M28-47-114 collected on day 30 resulted in 80.7 ± 12.0% complement-mediated bacteriolysis in vitro of the test MDR A. baumannii treated with imipenem, which was a higher level of bacteriolysis over sera from mice inoculated with I-M28-47. Macrophage-like U937 cells eliminated 49.3 ± 11.6% of the test MDR A. baumannii treated with imipenem when opsonized with sera from mice inoculated with I-M28-47-114, which was a higher level of elimination than observed for test MDR A. baumannii opsonized with sera from mice inoculated with I-M28-47. These results suggest that vaccination with I-M28-47-114 stimulated antibody responses capable of mounting high bactericidal killing of MDR A. baumannii. Therefore, the inactivated antibiotic-exposed whole-cell vaccine (I-M28-47-114) has potential for development as a candidate vaccine for broad clearance and protection against MDR A. baumannii infections. PMID:26923424

  17. Gene expression signatures in CD34+-progenitor-derived dendritic cells exposed to the chemical contact allergen nickel sulfate

    SciTech Connect

    Schoeters, Elke . E-mail: elke.schoeters@vito.be; Nuijten, Jean-Marie; Heuvel, Rosette L. van den; Nelissen, Inge; Witters, Hilda; Schoeters, Greet E.R.; Tendeloo, Vigor F.I. van; Berneman, Zwi N.; Verheyen, Geert R.

    2006-10-01

    The detection of the sensitizing potential of chemicals is of great importance to industry. A promising in vitro alternative to the currently applied animal assays for sensitization testing makes use of dendritic cells (DCs) that have the capability to process and present antigens to naive T cells and induce their proliferation. Here, we studied changes in gene expression profiles after exposing DCs to the contact allergen nickel sulfate. CD34+-progenitor-derived DCs, initiated from 3 different donors, were exposed to 60 {mu}M nickel sulfate, during 0.5, 1, 3, 6, 12 and 24 h. cDNA microarrays were used to assess the transcriptional activity of about 11,000 genes. Significant changes in the expression of 283 genes were observed; 178 genes were up-regulated and 93 down-regulated. These genes were involved in metabolism, cell structure, immune response, transcription, signal transduction, transport, and apoptosis. No functional information was found for 74 genes. Real-time RT-PCR was used to confirm the microarray results of 12 genes. In addition, 3 DC maturation markers not present on the microarrays (DEC205, DC LAMP and CCR7) were analyzed using real-time RT-PCR and found to be up-regulated at several time points. Our data indicate that a broad range of biological processes is influenced by nickel. Some processes are clearly linked to the immune response and DC maturation, others may indicate a toxic effect of nickel.

  18. Protein thiol oxidation and formation of S-glutathionylated cyclophilin A in cells exposed to chloramines and hypochlorous acid.

    PubMed

    Stacey, Melissa M; Cuddihy, Sarah L; Hampton, Mark B; Winterbourn, Christine C

    2012-11-01

    Neutrophil oxidants, including the myeloperoxidase products, HOCl and chloramines, have been linked to endothelial dysfunction in inflammatory diseases such as atherosclerosis. As they react preferentially with sulfur centers, thiol proteins are likely to be cellular targets. Our objectives were to establish whether there is selective protein oxidation in vascular endothelial cells treated with HOCl or chloramines, and to identify sensitive proteins. Cells were treated with HOCl, glycine chloramine and monochloramine, reversibly oxidized cysteines were labeled and separated by 1D or 2D SDS-PAGE, and proteins were characterized by mass spectrometry. Selective protein oxidation was observed, with chloramines and HOCl causing more changes than H(2)O(2). Cyclophilin A was one of the most sensitive targets, particularly with glycine chloramine. Cyclophilin A was also oxidized in Jurkat T cells where its identity was confirmed using a knockout cell line. The product was a mixed disulfide with glutathione, with glutathionylation at Cys-161. Glyceraldehyde-3-phosphate dehydrogenase, peroxiredoxins and cofilin were also highly sensitive to HOCl/chloramines. Cyclophilins are becoming recognized as redox regulatory proteins, and glutathionylation is an important mechanism for redox regulation. Cells lacking Cyclophilin A showed more glutathionylation of other proteins than wild-type cells, suggesting that cyclophilin-regulated deglutathionylation could contribute to redox changes in HOCl/chloramine-exposed cells.

  19. Novel type 1 photosensitizers: viability of leukemia cells exposed to reactive intermediates generated in situ by in vitro photofragmentation

    NASA Astrophysics Data System (ADS)

    Rajagopalan, Raghavan; Karwa, Amol; Lusiak, Przemyslaw M.; Srivastava, Kripa; Poreddy, Amruta R.; Pandurangi, Raghootama S.; Galen, Karen P.; Neumann, William L.; Cantrell, Gary E.; Dorshow, Richard B.

    2009-06-01

    Photodynamic therapy of tumors involving Type 2 photosenstizers has been conspicuously successful, but the Type 1 process, in contrast, has not received much attention despite its considerable potential. Accordingly, several classes of molecules containing fragile bonds such as azido (-N=N=N), azo (-N=N-), sulfenato (-S-O-) and oxaza (-N-O-) functional groups that produce reactive intermediates such as radicals and nitrenes upon photoexcitation were prepared and tested for cell viability using U397 leukemia cell line. The azido photosensitizer was conjugated to leukemia cell binding peptide, SFFWRLS, for targeted cell viability study. The cells were incubated with the photosensitizer at various concentrations, and were illuminated for 5, 10, and 20 minutes. The results show that all the photosensitizers caused cell death compared to the controls when exposed to both the photosensitizers and light. Most importantly, selective cell death was observed with the azido peptide conjugate 6, which clearly demonstrates that these Type 1 sensitizers are useful for phototherapeutic applications.

  20. Anti-Inflammatory Effects of Pomegranate Peel Extract in THP-1 Cells Exposed to Particulate Matter PM10

    PubMed Central

    Park, Soojin; Seok, Jin Kyung; Kwak, Jun Yup; Suh, Hwa-Jin; Kim, Young Mi; Boo, Yong Chool

    2016-01-01

    Epidemiological and experimental evidence support health risks associated with the exposure to airborne particulate matter with a diameter of <10 μM (PM10). PM10 stimulates the production of reactive oxygen species (ROS) and inflammatory mediators. Thus, we assumed that natural antioxidants might provide health benefits attenuating hazardous effects of PM10. In the present study, we examined the effects of pomegranate peel extract (PPE) on THP-1 monocytic cells exposed to PM10. PM10 induced cytotoxicity and the production of ROS. It also increased the expression and secretion of inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and monocyte chemoattractant protein-1 (MCP-1), and cell adhesion molecules, such as intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). PPE at 10–100 μg mL−1 attenuated the production of ROS and the expression of TNF-α, IL-1β, MCP-1, and ICAM-1, but not VCAM-1, in THP-1 cells stimulated by PM10 (100 μg mL−1). PPE also attenuated the adhesion of PM10-stimulated THP-1 cells to EA.hy926 endothelial cells. PPE constituents, punicalagin and ellagic acid, attenuated PM10-induced monocyte adhesion to endothelial cells, and punicalagin was less cytotoxic compared to ellagic acid. The present study suggests that PPE and punicalagin may be useful in alleviating inflammatory reactions due to particulate matter. PMID:27247608

  1. Apoptotic regulation and mutagenesis in human cells exposes to charged particles of importance for spaceflight

    NASA Astrophysics Data System (ADS)

    Kronenberg, A.; Gauny, S.; Hain, J.; Wu, P.; Wiese, C.

    Exposure to ionizing radiation can elicit two modes of cell death - necrosis or apoptosis. In human lymphoid cells, the predominant mechanism of radiation- induced cell death is apoptosis. The most likely exposure of individual human cells to heavy ions (e.g. Fe or Si) during spaceflight will result from single particle traversals. Here we report the fluence-response for apoptosis in human TK6 B- lymp hoblasts and provide evidence that single Fe ion traversals can stimulate an apoptotic response. The apoptotic response to charged particle exposures includes scrambling of the phospholipid bilayer in the cell membrane, activation of caspase signaling cascades and degradation of DNA into oligonucleosomes. We have also explored the importance of apoptotic regulation on the frequency and spectrum of mutations arising after exposure to charged particles. We used isogenic derivatives of TK6 cells stably transfected with pSFFV-neo-bcl-xL (encoding the anti-apoptotic gene BCL-XL and the neomycin resistance gene) or with pSFFV neo (encoding only- the neomycin resistance gene). TK6-bclxL cells were more susceptible to mutations at the TK1 locus than TK6-neo cells following exposure to protons, silicon ions or Fe ions. Molecular analysis demonstrated that most Fe-ion-induced mutations arose by loss of heterozygosity (LOH). In TK6-bclxL cells, more of the LOH occurred via mitotic recombination than in TK6-neo cells where the predominant mode of LOH was via deletion. We are currently mapping the LOH tracts to further define the biological bases for the differential sensitivity to Fe-ion-induced mutagenesis as a function of the genotype of the cell at risk. Supported by NASA grant T-964W to A. Kronenberg

  2. Anatase TiO2 Nanoparticles with Exposed {001} Facets for Efficient Dye-Sensitized Solar Cells

    PubMed Central

    Chu, Liang; Qin, Zhengfei; Yang, Jianping; Li, Xing’ao

    2015-01-01

    Anatase TiO2 nanoparticles with exposed {001} facets were synthesized from Ti powder via a sequential hydrothermal reaction process. At the first-step hydrothermal reaction, H-titanate nanowires were obtained in NaOH solution with Ti powder, and at second-step hydrothermal reaction, anatase TiO2 nanoparticles with exposed {001} facets were formed in NH4F solution. If the second-step hydrothermal reaction was carried out in pure water, the H-titanate nanowires were decomposed into random shape anatase-TiO2 nanostructures, as well as few impurity of H2Ti8O17 phase and rutile TiO2 phase. Then, the as-prepared TiO2 nanostructures synthesized in NH4F solution and pure water were applied to the photoanodes of dye-sensitized solar cells (DSSCs), which exhibited power conversion efficiency (PCE) of 7.06% (VOC of 0.756 V, JSC of 14.80 mA/cm2, FF of 0.631) and 3.47% (VOC of 0.764 V, JSC of 6.86 mA/cm2, FF of 0.662), respectively. The outstanding performance of DSSCs based on anatase TiO2 nanoparticles with exposed {001} facets was attributed to the high activity and large special surface area for excellent capacity of dye adsorption. PMID:26190140

  3. Enhanced proliferation, attachment and osteopontin expression by porcine periodontal cells exposed to Emdogain.

    PubMed

    Rincon, J C; Xiao, Y; Young, W G; Bartold, P M

    2005-12-01

    Emdogain (EMD) is an enamel matrix derivative extracted from developing porcine teeth with demonstrated periodontal regenerative potential. EMD has been shown to influence a number of properties of periodontal ligament cells including proliferation, cell attachment and matrix synthesis. To date, the effect of EMD on the epithelial cell rests of Malassez (ERM) is unknown. In this study, periodontal ligament fibroblasts, ERM, alveolar bone cells and gingival fibroblasts were obtained from porcine periodontal ligament, alveolar bone and gingiva. This study investigated, in vitro, the effect of EMD at three concentrations on proliferation, cell attachment and expression of mRNA for two mineralised tissue-related proteins (osteopontin and bone sialoprotein). As for other periodontal cells, the ERM proliferative response was enhanced by EMD. Attachment assays revealed a highly significant increase for ERM and gingival fibroblasts after EMD treatment at all concentrations. This study has also shown that EMD stimulated expression of osteopontin mRNA by ERM and alveolar bone cells. The results from this study provide evidence that EMD enhanced cellular events related with proliferation, attachment and osteopontin mRNA expression by porcine periodontal cells, in a manner consistent with its role in periodontal regenerative therapy.

  4. Ultrasound pretreatment of filamentous algal biomass for enhanced biogas production.

    PubMed

    Lee, Kwanyong; Chantrasakdakul, Phrompol; Kim, Daegi; Kong, Mingeun; Park, Ki Young

    2014-06-01

    The filamentous alga Hydrodictyon reticulatum harvested from a bench-scale wastewater treatment pond was used to evaluate biogas production after ultrasound pretreatment. The effects of ultrasound pretreatment at a range of 10-5000 J/mL were tested with harvested H. reticulatum. Cell disruption by ultrasound was successful and showed a higher degree of disintegration at a higher applied energy. The range of 10-5000 J/mL ultrasound was able to disintegrated H. reticulatum and the soluble COD was increased from 250 mg/L to 1000 mg/L at 2500 J/mL. The disintegrated algal biomass was digested for biogas production in batch experiments. Both cumulative gas generation and volatile solids reduction data were obtained during the digestion. Cell disintegration due to ultrasound pretreatment increased the specific biogas production and degradation rates. Using the ultrasound approach, the specific methane production at a dose of 40 J/mL increased up to 384 mL/g-VS fed that was 2.3 times higher than the untreated sample. For disintegrated samples, the volatile solids reduction was greater with increased energy input, and the degradation increased slightly to 67% at a dose of 50 J/mL. The results also indicate that disintegration of the algal cells is the essential step for efficient anaerobic digestion of algal biomass.

  5. Transcriptome analysis of the human T lymphocyte cell line Jurkat and human peripheral blood mononuclear cells exposed to deoxynivalenol (DON): New mechanistic insights

    SciTech Connect

    Katika, Madhumohan R.; Hendriksen, Peter J.M.; Shao, Jia; Loveren, Henk van; Peijnenburg, Ad

    2012-10-01

    Deoxynivalenol (DON) or vomitoxin is a commonly encountered type-B trichothecene mycotoxin, produced by Fusarium species predominantly found in cereals and grains. DON is known to exert toxic effects on the gastrointestinal, reproductive and neuroendocrine systems, and particularly on the immune system. Depending on dose and exposure time, it can either stimulate or suppress immune function. The main objective of this study was to obtain a deeper insight into DON-induced effects on lymphoid cells. For this, we exposed the human T-lymphocyte cell line Jurkat and human peripheral blood mononuclear cells (PBMCs) to various concentrations of DON for various times and examined gene expression changes by DNA microarray analysis. Jurkat cells were exposed to 0.25 and 0.5 μM DON for 3, 6 and 24 h. Biological interpretation of the microarray data indicated that DON affects various processes in these cells: It upregulates genes involved in ribosome structure and function, RNA/protein synthesis and processing, endoplasmic reticulum (ER) stress, calcium-mediated signaling, mitochondrial function, oxidative stress, the NFAT and NF-κB/TNF-α pathways, T cell activation and apoptosis. The effects of DON on the expression of genes involved in ER stress, NFAT activation and apoptosis were confirmed by qRT-PCR. Other biochemical experiments confirmed that DON activates calcium-dependent proteins such as calcineurin and M-calpain that are known to be involved in T cell activation and apoptosis. Induction of T cell activation was also confirmed by demonstrating that DON activates NFATC1 and induces its translocation from the cytoplasm to the nucleus. For the gene expression profiling of PBMCs, cells were exposed to 2 and 4 μM DON for 6 and 24 h. Comparison of the Jurkat microarray data with those obtained with PBMCs showed that most of the processes affected by DON in the Jurkat cell line were also affected in the PBMCs. -- Highlights: ► The human T cell line Jurkat and human

  6. Modulation of viability and apoptosis of UVB-exposed human keratinocyte HaCaT cells by aqueous methanol extract of laver (Porphyra yezoensis).

    PubMed

    Kim, Saerong; You, Dong Hun; Han, Taejun; Choi, Eun-Mi

    2014-12-01

    We investigated the effect of 80% methanol extract of laver (Porphyra yezoensis) on the UVB-exposed HaCaT cells, human keratinocytes. The laver extract showed absorbance spectrum characteristic of porphyra-334 or shinorine, major mycosporine-like amino acids (MAAs) in red algae, and contained phenolic compounds. UVB exposure decreased cell viability and increased apoptotic cell fractions, and it also decreased the ratio of reduced (GSH) to oxidized glutathione (GSSG) and the total glutathione content. Post-treatment with the laver extract significantly increased the net viability and also the apoptotic cell fractions of UVB-exposed cells. The extract caused increase in GSH/GSSG ratio, yet it exacerbated the decrease in glutathione content in the UVB-exposed cells. These effects of the laver extract were also manifested in the sham-exposed cells, suggesting that those effects might be general phenomena caused by the laver extract. The extract treatment enhanced the UVB-induced phosphorylation of JNK and ERK, affecting more the latter. Our results suggest that the post-treatment with laver extract may protect UVB-exposed skin cells not only by increasing overall cell proliferation but also by enhancing apoptosis of damaged cells, via activating JNK and ERK signaling pathways, in which modulation of the content and redox status of glutathione may take significant parts.

  7. Structural damage of chicken red blood cells exposed to platinum nanoparticles and cisplatin.

    PubMed

    Kutwin, Marta; Sawosz, Ewa; Jaworski, Sławomir; Kurantowicz, Natalia; Strojny, Barbara; Chwalibog, André

    2014-01-01

    Side effects and resistance of cancer cells to cisplatin are major drawbacks to its application, and recently, the possibility of replacing cisplatin with nanocompounds has been considered. Most chemotherapeutic agents are administered intravenously, and comparisons between the interactions of platinum nanoparticles (NP-Pt) and cisplatin with blood compartments are important for future applications. This study investigated structural damage, cell membrane deformation and haemolysis of chicken embryo red blood cells (RBC) after treatment with cisplatin and NP-Pt. Cisplatin (4 μg/ml) and NP-Pt (2,6 μg/ml), when incubated with chicken embryo RBC, were detrimental to cell structure and induced haemolysis. The level of haemolytic injury was increased after cisplatin and NP-Pt treatments compared to the control group. Treatment with cisplatin caused structural damage to cell membranes and the appearance of keratocytes, while NP-Pt caused cell membrane deformations (discoid shape of cells was lost) and the formation of knizocytes and echinocytes. This work demonstrated that NP-Pt have potential applications in anticancer therapy, but potential toxic side effects must be explored in future preclinical research.

  8. Structural damage of chicken red blood cells exposed to platinum nanoparticles and cisplatin

    NASA Astrophysics Data System (ADS)

    Kutwin, Marta; Sawosz, Ewa; Jaworski, Sławomir; Kurantowicz, Natalia; Strojny, Barbara; Chwalibog, André

    2014-05-01

    Side effects and resistance of cancer cells to cisplatin are major drawbacks to its application, and recently, the possibility of replacing cisplatin with nanocompounds has been considered. Most chemotherapeutic agents are administered intravenously, and comparisons between the interactions of platinum nanoparticles (NP-Pt) and cisplatin with blood compartments are important for future applications. This study investigated structural damage, cell membrane deformation and haemolysis of chicken embryo red blood cells (RBC) after treatment with cisplatin and NP-Pt. Cisplatin (4 μg/ml) and NP-Pt (2,6 μg/ml), when incubated with chicken embryo RBC, were detrimental to cell structure and induced haemolysis. The level of haemolytic injury was increased after cisplatin and NP-Pt treatments compared to the control group. Treatment with cisplatin caused structural damage to cell membranes and the appearance of keratocytes, while NP-Pt caused cell membrane deformations (discoid shape of cells was lost) and the formation of knizocytes and echinocytes. This work demonstrated that NP-Pt have potential applications in anticancer therapy, but potential toxic side effects must be explored in future preclinical research.

  9. Responses of Pseudokirchneriella subcapitata and algal assembly to photocatalytic titanium dioxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Metzler, David M.

    varied with algal age and TiO 2 concentration. Finally, the effect of light intensity was examined for both visible and UV wavelengths. The greatest effect was for 1000 mg/L of TiO2 under varying light. Peak maximums occurred for chlorophyll a and lipid peroxidation. Peak minimums occurred for population. Varying UV light intensity resulted in decreased population for 100 and 1000 mg/L of TiO2. Additionally, chlorophyll a reached a maximum at 17 and 5 x the control values under 66% UV light for 100 and 1000 mg/L of TiO 2, respectively. The effect of copper and phenol to P. subcapitata was examined in the presence of TiO2. Copper in the presence of TiO 2 increased both chlorophyll a and lipid peroxidation greater than in the presence of TiO2 alone. Optimum conditions were observed for both endpoints. When algae were exposed to Cu and TiO2 the compounds acted independently of each other, having an additive effect on population. The TiO2 acted as a protective barrier against phenol toxicity at low phenol concentrations. At high phenol concentrations the toxicity of both phenol and TiO2 increased. Both compounds acted to disrupt the cell wall stability as seen with microscopy imaging. This was presumed to be through destruction of the Ca-pectinate within the cell wall, as indicated by increased soluble Ca correlated with phenol concentrations. The effect of TiO2 on cell barriers and natural algal assemblage was investigated. SEM images reveal that algae exposed to TiO2 have DNA external to the cell. Under hypotonic stress the loss of electrolytes was less controlled when the total number of nanoparticles was 1010 in the sample, at d1 less than 46 nm. At d1 greater than 46 nm no effect on electrolyte regulation was noted. Natural algal assemblages exposed to TiO2 varied there fatty acid (FA) content. This could be due to selective growth resistant reactive oxygen species (ROS) organisms or the percentages of certain FAs were decreased because of sensitivity to ROS. (Abstract

  10. DNA damage and apoptosis of endometrial cells cause loss of the early embryo in mice exposed to carbon disulfide

    SciTech Connect

    Zhang, Bingzhen; Shen, Chunzi; Yang, Liu; Li, Chunhui; Yi, Anji; Wang, Zhiping

    2013-12-01

    Carbon disulfide (CS{sub 2}) may lead to spontaneous abortion and very early pregnancy loss in women exposed in the workplace, but the mechanism remains unclear. We designed an animal model in which gestating Kunming strain mice were exposed to CS{sub 2} via i.p. on gestational day 4 (GD4). We found that the number of implanted blastocysts on GD8 was significantly reduced by each dose of 0.1 LD{sub 50} (157.85 mg/kg), 0.2 LD{sub 50} (315.7 mg/kg) and 0.4 LD{sub 50} (631.4 mg/kg). In addition, both the level of DNA damage and apoptosis rates of endometrial cells on GD4.5 were increased, showed definite dose–response relationships, and inversely related to the number of implanted blastocysts. The expressions of mRNA and protein for the Bax and caspase-3 genes in the uterine tissues on GD4.5 were up-regulated, while the expressions of mRNA and protein for the Bcl-2 gene were dose-dependently down-regulated. Our results indicated that DNA damage and apoptosis of endometrial cells were important reasons for the loss of implanted blastocysts induced by CS{sub 2}. - Highlights: • We built an animal model of CS2 exposure during blastocyst implantation. • Endometrial cells were used in the comet assay to detect DNA damage. • CS2 exposure caused DNA damage and endometrial cell apoptosis. • DNA damage and endometrial cell apoptosis were responsible for embryo loss.

  11. Inter- and Intra-Chromosomal Aberrations in Human Cells Exposed in vitro to High and Low LET Radiations

    NASA Technical Reports Server (NTRS)

    Hada, M.; Wilkins, R.; Saganti, P. B.; Gersey, B.; Cucinotta, F. A.; Wu, H.

    2006-01-01

    Energetic heavy ions pose a health risk to astronauts in extended ISS and future Mars missions. High-LET heavy ions are particularly effective in causing various biological effects including cell inactivation, genetic mutations and cancer induction. Most of these biological endpoints are closely related to chromosomal damage, which can be utilized as a biomarker for radiation insults. Previously, we had studied chromosome aberrations in human lymphocytes and fibroblasts induced by both low- and high-LET radiation using FISH and multicolor fluorescence in situ hybridization (mFISH) techniques. In this study, we exposed human epithelial cells in vitro to gamma rays and energetic particles of varying types and energies and dose rates, and analyzed chromosomal damages using the multicolor banding in situ hybridization (mBAND) procedure. Confluent human epithelial cells (CH184B5F5/M10) were exposed to energetic heavy ions at NASA Space Radiation Laboratory (NSRL) at the Brookhaven National Laboratory, high energy neutron at the Los Alamos Nuclear Science Center (LANSCE) or Cs-137-gamma radiation source at the University of Texas, MD Anderson Cancer Center. After colcemid and Calyculin A treatment, cells were fixed and painted with XCyte3 mBAND kit (MetaSystems) and chromosome aberrations were analyzed with mBAND analysis system (MetaSystems). With this technique, individually painted chromosomal bands on one chromosome allowed the identification of interchromosomal aberrations (translocation to unpainted chromosomes) and intrachromosomal aberrations (inversions and deletions within a single painted chromosome). The results of the mBAND study showed a higher ratio of inversion involved with interchromosomal exchange in heavy ions compared to -ray irradiation. Analysis of chromosome aberrations using mBAND has the potential to provide useful information on human cell response to space-like radiation.

  12. Rcan1-1L overexpression induces mitochondrial autophagy and improves cell survival in angiotensin II-exposed cardiomyocytes

    SciTech Connect

    Duan, Hongyan; Li, Yongqiang; Yan, Lijie; Yang, Haitao; Wu, Jintao; Qian, Peng; Li, Bing; Wang, Shanling

    2015-07-01

    Mitochondrial autophagy is an important adaptive stress response and can be modulated by various key molecules. A previous study found that the regulator of calcineurin 1-1L (Rcan1-1L) may regulate mitochondrial autophagy and cause mitochondria degradation in neurocytes. However, the effect of Rcan1-1L on cardiomyocytes has not been determined. In the present study, we aimed to investigate the role of Rcan1-1L in angiotensin II (Ang II)-exposed human cardiomyocytes. Above all, Human adult cardiac myocytes (HACMs) were exposed to 200 nmol/L Ang II for 4 days. Enhanced H{sub 2}O{sub 2} production, cytochrome C release and mitochondrial permeability were observed in these cells, which were blocked by valsartan. Consistently, Ang II exposure significantly reduced cardiomyocyte viability. However, transfection of Rcan1-1L vector promoted cell viability and ameliorated the apoptosis caused by Ang II. Rcan1-1L clearly promoted mitochondrial autophagy in HACMs, with elevated autophagy protein (ATG) 5 and light chain 3 (LC3) expression. Transient mitochondrial biogenesis and reduced cytochrome C release was also induced by Rcan1-1L. Additionally, Rcan1-1L significantly inhibited calcineurin/nuclear factor of activated T cells (NFAT) signaling. We thus conclude that Rcan1-1L may play a protective role in Ang II-treated cardiomyocytes through the induction of mitochondrial autophagy, and may be an alternative method of cardiac protection. - Highlights: • Transfection of Rcan1-1L into HACMs promoted cell viability and reduced apoptosis. • Transfection of Rcan1-1L promoted mitochondrial autophagy in HACMs. • Rcan1-1L inhibited the calcineurin/nuclear factor of activated T cells signaling.

  13. Sixty years in algal physiology and photosynthesis.

    PubMed

    Pirson, A

    1994-06-01

    This personal perspective records research experiences in chemistry and biology at four German universities, two before and two after World War II. The research themes came from cytophysiology of green unicellular algae, in particular their photosynthesis. The function of inorganic ions in photosynthesis and dark respiration was investigated at different degrees of specific mineral stress (deficiencies), and the kinetics of recovery followed after the addition of the missing element. Two types of recovery of photosynthesis were observed: indirect restitution via growth processes and immediate normalisation. From the latter case (K(+), phosphate, Mn(++)) the effect of manganese was emphasized as its role in photosynthetic O2 evolution became established during our research. Other themes of our group, with some bearing on photosynthesis were: synchronization of cell growth by light-dark change and effects of blue (vs. red) light on the composition of green cells. Some experiences in connection with algal mass cultures are included. Discussion of several editorial projects shows how photosynthesis, as an orginally separated field of plant biochemistry and biophysics, became included into general cell physiology and even ecophysiology of green plants. The paper contains an appreciation of the authors' main mentor Kurt Noack (1888-1963) and of Ernst Georg Pringsheim (1881-1970), founder of experimental phycology.

  14. Potentially-lethal damage and radioprotection in human cells exposed to californium-252

    SciTech Connect

    Schroy, C.B.; Goud, S.N.; Magura, C.; Feola, J.M.; Maruyama, Y.

    1986-01-01

    Cultured human T-1E cells were irradiated with californium-252 neutrons and gamma rays. When 2 mm caffeine was present in the medium for 47 h after irradiation cell survival (assayed by colony formation) was decreased significantly. When 2 m dimethylsulfoxide was present during the irradiations radioprotection was observed using the same assay. The caffeine data indicate that potentially-lethal lesions exist in cells after californium exposure and that these lesions can be made lethal when they would otherwise be repaired. The DMSO data indicate that radioprotection from californium exposure can be achieved and that scanvengable free radicals play an important role in Cf-252 lethality.

  15. Effects of laser-exposed gold nanorods on biochemical pathways of neuronal cells

    NASA Astrophysics Data System (ADS)

    Paviolo, Chiara; Haycock, John W.; Stoddart, Paul R.; McArthur, Sally L.

    2013-12-01

    Gold nanorods with citrate termination, poly(4 - styrenesulfonic acid) coating and silica coating were taken up by NG108 - K15 neuronal cells. This process proved to generate reactive oxygen species (ROS) and activate the nuclear factor κ -B (NF - κB). However, subsequent exposure to laser light at the plasmon resonance wavelength showed no long term cell damage or ROS / NF- κB activation. Interestingly, monitoring of intracellular Ca2+ signaling showed evidence of photo - generated transients without alteration of other normal cell functions. These results suggest new opportunities for peripheral nerve regeneration treatments and for infrared neural stimulation.

  16. Nitric oxide measurements in hTERT-RPE cells and subcellular fractions exposed to low levels of red light

    NASA Astrophysics Data System (ADS)

    Wigle, Jeffrey C.; Castellanos, Cherry C.; Denton, Michael L.; Holwitt, Eric A.

    2014-02-01

    Cells in a tissue culture model for laser eye injury exhibit increased resistance to a lethal pulse of 2.0-μm laser radiation if the cells are first exposed to 2.88 J/cm2 of red light 24 hr prior to the lethal laser exposure. Changes in expression of various genes associated with apoptosis have been observed, but the biochemical link between light absorption and gene expression remains unknown. Cytochome c oxidase (CCOX), in the electron transport chain, is the currentlyhypothesized absorber. Absorption of the red light by CCOX is thought to facilitate displacement of nitric oxide (NO) by O2 in the active site, increasing cellular respiration and intracellular ATP. However, NO is also an important regulator and mediator of numerous physiological processes in a variety of cell and tissue types that is synthesized from l-arginine by NO synthases. In an effort to determine the relative NO contributions from these competing pathways, we measured NO levels in whole cells and subcellular fractions, with and without exposure to red light, using DAF-FM, a fluorescent dye that stoichiometrically reacts with NO. Red light induced a small, but consistently reproducible, increase in fluorescence intensity in whole cells and some subcellular fractions. Whole cells exhibited the highest overall fluorescence intensity followed by (in order) cytosolic proteins, microsomes, then nuclei and mitochondria.

  17. Transcriptomic and metabolomic approaches to investigate the molecular responses of human cell lines exposed to the flame retardant hexabromocyclododecane (HBCD).

    PubMed

    Zhang, Jinkang; Williams, Timothy D; Abdallah, Mohamed Abou-Elwafa; Harrad, Stuart; Chipman, James K; Viant, Mark R

    2015-12-01

    The potential for human exposure to the brominated flame retardant, hexabromocyclododecane (HBCD) has given rise to health concerns, yet there is relatively limited knowledge about its possible toxic effects and the underlying molecular mechanisms that may mediate any impacts on health. In this study, unbiased transcriptomic and metabolomic approaches were employed to investigate the potential molecular changes that could lead to the toxicity of HBCD under concentrations relevant to human exposure conditions using in vitro models. A concentration-dependent cytotoxic effect of HBCD to A549 and HepG2/C3A cells was observed based on MTT assays or CCK-8 assays with EC50 values of 27.4 μM and 63.0 μM, respectively. Microarray-based transcriptomics and mass spectrometry-based metabolomics revealed few molecular changes in A549 cells or HepG2/C3A cells following a 24-hour exposure to several sub-lethal concentrations (2 to 4000 nM) of HBCD. Quantification of the level of HBCD in the HepG2/C3A exposed cells suggested that the flame retardant was present at concentrations several orders of magnitude higher than those reported to occur in human tissues. We conclude that at the concentrations known to be achievable following exposure in humans, HBCD exhibits no detectable acute toxicity in A549 cells, representative of the lung, or in HepG2/C3A cells, that are hepatocytes with some xenobiotic metabolic capacity.

  18. Monitoring Intracellular Redox Changes in Ozone-exposed airway epithelial cells

    EPA Science Inventory

    Background: The toxicity of many compounds involves oxidative injury to cells. Direct assessment of mechanistic events involved in xenobiotic-induced oxidative stress is not easily achievable. Development of genetically-encoded probes designed for monitoring intracellular redox s...

  19. Bioaccumulation of algal toxins and changes in physiological parameters in Mediterranean mussels from the North Adriatic Sea (Italy).

    PubMed

    Buratti, Sara; Franzellitti, Silvia; Poletti, Roberto; Ceredi, Alfiero; Montanari, Giuseppe; Capuzzo, Antonio; Fabbri, Elena

    2013-08-01

    The Northwestern Adriatic Sea is a commercially important area in aquaculture, accounting for about 90% of the Italian mussel production, and it was subjected to recurring cases of mussel farm closures due to toxic algae poisoning. A spatial and temporal survey of four sites along the North Adriatic Sea coasts of Emilia Romagna (Italy) was undertaken to study the possible impairments of physiological parameters in Mytilus galloprovincialis naturally exposed to algal toxins. The sites were selected as part of the monitoring network for the assessment of algal toxins bioaccumulation by the competent Authority. Samples positive to paralytic shellfish toxins and to lipophilic toxins were detected through the mouse bioassay. Lipophilic toxins were assessed by HPLC. Decreasing yessotoxins (YTX) levels were observed in mussels from June to December, while homo-YTX contents increased concomitantly. Lysosome membrane stability (LMS), glutathione S-transferase and catalase activities, and multixenobiotic resistance (MXR)-related gene expressions were assessed as parameters related to the mussel health status and widely utilized in environmental biomonitoring. Levels of cAMP were also measured, as possibly involved in the algal toxin mechanisms of action. Low LMS values were observed in hemocytes from mussels positive to the mouse bioassay. MXR-related gene expressions were greatly inhibited in mussels positive to the mouse bioassay. Clear correlations were established between increasing homo-YTX contents (and decreasing YTX) and increasing cAMP levels in the tissues. Similarly, significant correlations were established between the increase of homo-YTX and cAMP levels, and the expressions of three MXR-related genes at submaximal toxin concentrations. In conclusion, YTXs may affect mussel physiological parameters, including hemocyte functionality, gene expression and cell signaling.

  20. Proliferation and mRNA expression of absorptive villous cell markers and mineral transporters in prolactin-exposed IEC-6 intestinal crypt cells.

    PubMed

    Teerapornpuntakit, Jarinthorn; Wongdee, Kannikar; Thongbunchoo, Jirawan; Krishnamra, Nateetip; Charoenphandhu, Narattaphol

    2012-06-01

    During pregnancy and lactation, prolactin (PRL) enhances intestinal absorption of calcium and other minerals for fetal development and milk production. Although an enhanced absorptive efficiency is believed to mainly result from the upregulation of mineral transporters in the absorptive villous cells, some other possibilities, such as PRL-enhanced crypt cell proliferation and differentiation to increase the absorptive area, have never been ruled out. Here, we investigated cell proliferation and mRNA expression of mineral absorption-related genes in the PRL-exposed IEC-6 crypt cells. As expected, the cell proliferation was not altered by PRL. Inasmuch as the mRNA expressions of villous cell markers, including dipeptidylpeptidase-4, lactase and glucose transporter-5, were not increased, PRL was not likely to enhance crypt cell differentiation into the absorptive villous cells. In contrast to the previous findings in villous cells, PRL was found to downregulate the expression of calbindin-D(9k), claudin-3 and occludin in IEC-6 crypt cells, while having no effect on transient receptor potential vanilloid family channels-5/6, plasma membrane Ca(2+)-ATPase (PMCA)-1b and Na(+)/Ca(2+) exchanger-1 expression. In conclusion, IEC-6 crypt cells did not respond to PRL by increasing proliferation or differentiation into villous cells. The present results thus supported the previous hypothesis that PRL enhanced mineral absorption predominantly by increasing transporter expression and activity in the absorptive villous cells.

  1. Antimutagenicity of WR-1065 in L5178Y cells exposed to accelerated (56)Fe ions

    NASA Technical Reports Server (NTRS)

    Evans, H. H.; Evans, T. E.; Horng, M. F.

    2002-01-01

    The ability of the aminothiol WR-1065 [N-(2-mercaptoethyl)-1,3-diaminopropane] to protect L5178Y (LY) cells against the cytotoxic and mutagenic effects of exposure to accelerated (56)Fe ions (1.08 GeV/nucleon) was determined. It was found that while WR-1065 reduced the mutagenicity in both cell lines when it was present during the irradiation, the addition of WR-1065 after the exposure had no effect on the mutagenicity of the radiation in either cell line. No marked protection against the cytotoxic effects of exposure to (56)Fe ions was provided by WR-1065 when added either during or after irradiation in either cell line. We reported previously that WR-1065 protected the LY-S1 and LY-SR1 cell lines against both the cytotoxicity and mutagenicity of X radiation when present during exposure, but that its protection when administered after exposure was limited to the mutagenic effects in the radiation-hypersensitive cell line, LY-S1. The results indicate that the mechanisms involved differ in the protection against cytotoxic compared to mutagenic effects and in the protection against damage caused by accelerated (56)Fe ions compared to X radiation.

  2. Metabolic systems analysis to advance algal biotechnology.

    PubMed

    Schmidt, Brian J; Lin-Schmidt, Xiefan; Chamberlin, Austin; Salehi-Ashtiani, Kourosh; Papin, Jason A

    2010-07-01

    Algal fuel sources promise unsurpassed yields in a carbon neutral manner that minimizes resource competition between agriculture and fuel crops. Many challenges must be addressed before algal biofuels can be accepted as a component of the fossil fuel replacement strategy. One significant challenge is that the cost of algal fuel production must become competitive with existing fuel alternatives. Algal biofuel production presents the opportunity to fine-tune microbial metabolic machinery for an optimal blend of biomass constituents and desired fuel molecules. Genome-scale model-driven algal metabolic design promises to facilitate both goals by directing the utilization of metabolites in the complex, interconnected metabolic networks to optimize production of the compounds of interest. Network analysis can direct microbial development efforts towards successful strategies and enable quantitative fine-tuning of the network for optimal product yields while maintaining the robustness of the production microbe. Metabolic modeling yields insights into microbial function, guides experiments by generating testable hypotheses, and enables the refinement of knowledge on the specific organism. While the application of such analytical approaches to algal systems is limited to date, metabolic network analysis can improve understanding of algal metabolic systems and play an important role in expediting the adoption of new biofuel technologies.

  3. Induction of anchorage-independent growth in primary human cells exposed to protons or HZE ions separately or in dual exposures.

    PubMed

    Sutherland, B M; Cuomo, N C; Bennett, P V

    2005-10-01

    Travelers on space missions will be exposed to a complex radiation environment that includes protons and heavy charged particles. Since protons are present at much higher levels than are heavy ions, the most likely scenario for cellular radiation exposure will be proton exposure followed by a hit by a heavy ion. Although the effects of individual ion species on human cells are being investigated extensively, little is known about the effects of exposure to both radiation types. One useful measure of mammalian cell damage is induction of the ability to grow in a semi-solid agar medium highly inhibitory to the growth of normal human cells, termed neoplastic transformation. Using primary human cells, we evaluated induction of soft-agar growth and survival of cells exposed to protons only or to heavy charged particles (600 MeV/nucleon silicon) only as well as of cells exposed to protons followed after a 4-day interval by silicon ions. Both ions alone efficiently transformed the human cells to anchorage-independent growth. Initial experiments indicate that the dose responses for neoplastic transformation of cells exposed to protons and then after 4 days to silicon ions appear similar to that of cells exposed to silicon ions alone.

  4. DNA damage, cell kinetics and ODC activities studied in CBA mice exposed to electromagnetic fields generated by transmission lines.

    PubMed

    Svedenstål, B M; Johanson, K J; Mattsson, M O; Paulsson, L E

    1999-01-01

    CBA mice were exposed outdoors to 50 Hz electromagnetic fields (EMF), with a flux density of about 8 microT rms (root mean square), generated by a 220 kV transmission line. Assays were performed in order to investigate, the possible genotoxic effects after 11, 20 and 32 days of exposure, as well as the effects on body weight, leukocytes, erythrocytes, and the level of ornithine decarboxylase (ODC) activity in spleen and testis. DNA migration was studied on brain cells by single cell electrophoresis (comet assay). After 32 days of exposure a highly significant change of the tail/head ratio of the comets was observed (p < 0.001), showing DNA-damage. Further, a decreased number of mononuclear leukocytes (0.02 < p < 0.05) was observed in mice EMF-exposed for 20 days. In summary, our data indicate that transmission lines of this type may induce genotoxic effects in mice, seen as changes in the DNA migration. These results might have an important implication for health effects.

  5. Lack of Genomic Instability in Bone Marrow Cells of SCID Mice Exposed Whole-Body to Low-Dose Radiation

    PubMed Central

    Rithidech, Kanokporn Noy; Udomtanakunchai, Chatchanok; Honikel, Louise; Whorton, Elbert

    2013-01-01

    It is clear that high-dose radiation is harmful. However, despite extensive research, assessment of potential health-risks associated with exposure to low-dose radiation (at doses below or equal to 0.1 Gy) is still challenging. Recently, we reported that 0.05 Gy of 137Cs gamma rays (the existing limit for radiation-exposure in the workplace) was incapable of inducing significant in vivo genomic instability (measured by the presence of late-occurring chromosomal damage at 6 months post-irradiation) in bone marrow (BM) cells of two mouse strains, one with constitutively high and one with intermediate levels of the repair enzyme DNA-dependent protein-kinase catalytic-subunit (DNA-PKcs). In this study, we present evidence for a lack of genomic instability in BM cells of the severely combined-immunodeficiency (SCID/J) mouse (which has an extremely low-level of DNA-PKcs activity) exposed whole-body to low-dose radiation (0.05 Gy). Together with our previous report, the data indicate that low-dose radiation (0.05 Gy) is incapable of inducing genomic instability in vivo (regardless of the levels of DNA-PKcs activity of the exposed mice), yet higher doses of radiation (0.1 and 1 Gy) do induce genomic instability in mice with intermediate and extremely low-levels of DNA-PKcs activity (indicating an important role of DNA-PKcs in DNA repair). PMID:23549227

  6. UV-specific p53 and PTCH mutations in sporadic basal cell carcinoma of sun-exposed skin.

    PubMed

    Ratner, D; Peacocke, M; Zhang, H; Ping, X L; Tsou, H C

    2001-02-01

    UVB irradiation is known to produce DNA damage at mutation hotspots in the p53 tumor suppressor gene, leading to the development of skin cancers. Mutations in the PTCH tumor suppressor gene, which is known to be responsible for the development of nevoid basal cell carcinoma syndrome, have also been identified in sporadic basal cell carcinomas (BCCs). We describe the case of an 80-year-old welder in whom 3 novel p53 mutations, as well as UV-specific PTCH mutations, were detected in two BCC samples from sun-exposed skin. The simultaneous presence of UV-specific p53 and PTCH mutations in the same BCC sample has not previously been reported.

  7. Interferon-α curbs production of interleukin-22 by human peripheral blood mononuclear cells exposed to live Borrelia burgdorferi.

    PubMed

    Berner, Anika; Bachmann, Malte; Pfeilschifter, Josef; Kraiczy, Peter; Mühl, Heiko

    2015-10-01

    Cytokine networks initiated by means of innate immunity are regarded as a major determinant of host defence in response to acute infection by bacteria including Borrelia burgdorferi. Herein, we demonstrate that interferon (IFN)-α, either endogenously produced after exposure of cells to toll-like receptor-9-activating CpG oligonucleotides or provided as recombinant cytokine, weakens activation of the anti-bacterial interleukin (IL)-1/IL-22 axis in human peripheral blood mononuclear cells exposed to viable B. burgdorferi. As IFN-α has been related to pathological dissemination of the spirochaete, data suggest an immunoregulatory role of type I IFN in this context that is able to significantly modify cytokine profiles thereby possibly determining early course of B. burgdorferi infection.

  8. N-acetyl Glucosamine Distribution and Mitochondrial Activity of Tumor Cell Exposed to Photodynamic Therapy.

    PubMed

    Pinto, G P; Lopes, K A R; Salles, N G; Pacheco-Soares, C

    2016-11-01

    The use of lectins can play an important role for tracking modification on cell surface components, since lectins can be easily complexed with radioisotopes, biotin or fluorescein, facilitating the evaluation of carbohydrates distribution in the cell and mitochondrial activity. The aim of this study was to evaluate photodynamic therapy effects on indirect distribution of N-acetyl-glucosamine terminal glycoproteins, in human laryngeal carcinoma HEp-2 cell line surface, using lectin wheat germ agglutinin (WGA) and on mitochondrial activity, for the same cell line, using MitoTracker. The photosensitizer Aluminum Phthalocyanine Tetrasulfonate (AlPcS4) was administrated at 10 μM/mL, followed by an incubation period for its accumulation in the tumor cells, which were irradiated with laser diode λ = 685 nm and energy density of 4.5 J/cm(2). Our results indicated that, after Photodynamic Therapy (PDT), it was observed N-acetyl glucosamine terminal glycoprotein expression and mitochondrial O2 production, compared to the control group. Based on these results, we suggest that PDT influences the O2 mitochondrial production and the presence of surface glycoproteins N-acetyl glucosamine terminals.

  9. Poloxamer 188 reduces normal and phosphatidylserine-exposing erythrocyte adhesion to endothelial cells in dextran solutions.

    PubMed

    Koo, Stephanie; Yang, Yang; Neu, Björn

    2013-12-01

    Abnormal red blood cell (RBC) adhesion to endothelial cells (ECs) has been correlated with vascular complications in diseases such as sickle cell anemia and diabetes. Poloxamer 188 (P188) has been clinically tested to treat vaso-occlusion. However, the underlying mechanism(s) have not been clarified, making a methodical application difficult. In this study, we investigate how and to what extent P188 reduces RBC adhesion to ECs in plasma-like solutions. RBC adhesion to ECs is studied in solutions containing dextran, which is known to induce adhesion via macromolecular depletion interaction. It is demonstrated that P188 itself does not induce adhesion of normal RBCs to ECs but significantly reduces the adhesion in solutions containing high molecular mass-dextran. In addition, it is shown that P188 can reduce the adhesion of RBCs with enhanced exposure of phosphatidylserine (PS). Measurements of the electrophoretic mobility indicate that P188 increases the local viscosity inside the electric double layer of RBCs. Based on these results this study suggests that P188 reduces macromolecular depletion interaction, via penetrating into the depletion layer. Taking into consideration that dextran mimics the effects of pro-adhesive non-adsorbing plasma proteins and macromolecules, our study therefore suggests a mechanism for the adhesion reducing effect of P188 and should thus be of potential value for a detailed understanding of how cell-cell interactions in pathological conditions can be reduced.

  10. System for exposing cultured cells to intermittent hypoxia utilizing gas permeable cultureware.

    PubMed

    Polak, Jan; Studer-Rabeler, Karen; McHugh, Holly; Hussain, Mehboob A; Shimoda, Larissa A

    2015-07-01

    Tissue intermittent hypoxia (IH) occurs in obstructive sleep apnea, sickle cell anemia, physical exercise and other conditions. Poor gas solubility and slow diffusion through culture media hampers mimicking IH-induced transitions of O(2) in vitro. We aimed to develop a system enabling exposure of cultured cells to IH and to validate such exposure by real-time O(2) measurements and cellular responses. Standard 24-well culture plates and plates with bottoms made from a gas permeable film were placed in a heated cabinet. Desired cycling of O(2) levels was induced using programmable solenoids to purge mixtures of 95% N(2) + 5% CO(2) or 95% O(2) + 5% CO(2). Dissolved oxygen, gas pressure, temperature, and water evaporation were measured during cycling. IH-induced cellular effects were evaluated by hypoxia inducible factor (HIF) and NF-κB luciferase reporters in HEK296 cells and by insulin secretion in rat insulinoma cells. Oxygen cycling in the cabinet was translated into identical changes of O(2) at the well bottom in gas permeable, but not in standard cultureware. Twenty-four hours of IH exposure increased HIF (112%), NF-κB (111%) and insulin secretion (44%). Described system enables reproducible and prolonged IH exposure in cultured cells while controlling for important environmental factors.

  11. Combined genetic and epigenetic interferences with interferon signaling expose prostate cancer cells to viral infection

    PubMed Central

    Sabo, Yosef; Bacharach, Eran; Ehrlich, Marcelo

    2016-01-01

    Interferons (IFNs) induce anti-viral programs, regulate immune responses, and exert anti-proliferative effects. To escape anti-tumorigenic effects of IFNs, malignant cells attenuate JAK/STAT signaling and expression of IFN stimulated genes (ISGs). Such attenuation may enhance the susceptibility of tumor cells to oncolytic virotherapy. Here we studied genetic and epigenetic mechanisms of interference with JAK/STAT signaling and their contribution to susceptibility of prostate cancer cells to viral infection. Bioinformatics analysis of gene-expression in cohorts of prostate cancer patients revealed genetic and epigenetic interference with the IFN program. To correlate lack of IFN signaling and susceptibility to viral infection and oncolysis; we employed LNCaP prostate cancer cells as cellular model, and the human metapneumovirus and the epizootic hemorrhagic disease virus as infectious agents. In LNCaP cells, JAK1 is silenced by bi-allelic inactivating mutations and epigenetic silencing, which also silences ISGs. Chemical inhibition of epigenetic silencing partially restored IFN-sensitivity, induced low levels of expression of selected ISGs and attenuated, but failed to block, viral infection and oncolysis. Since viral infection was not blocked by epigenetic modifiers, and these compounds may independently-induce anti-tumor effects, we propose that epigenetic modifiers and virotherapy are compatible in treatment of prostate tumors defective in JAK1 expression and IFN signaling. PMID:27366948

  12. Didymosphenia geminata: Algal blooms in oligotrophic streams and rivers

    NASA Astrophysics Data System (ADS)

    Sundareshwar, P. V.; Upadhayay, S.; Abessa, M.; Honomichl, S.; Berdanier, B.; Spaulding, S. A.; Sandvik, C.; Trennepohl, A.

    2011-05-01

    In recent decades, the diatom Didymosphenia geminata has emerged as nuisance species in river systems around the world. This periphytic alga forms large “blooms” in temperate streams, presenting a counterintuitive result: the blooms occur primarily in oligotrophic streams and rivers, where phosphorus (P) availability typically limits primary production. The goal of this study is to examine how high algal biomass is formed under low P conditions. We reveal a biogeochemical process by which D. geminata mats concentrate P from flowing waters. First, the mucopolysaccaride stalks of D. geminata adsorb both iron (Fe) and P. Second, enzymatic and bacterial processes interact with Fe to increase the biological availability of P. We propose that a positive feedback between total stalk biomass and high growth rate is created, which results in abundant P for cell division. The affinity of stalks for Fe in association with iron-phosphorus biogeochemistry suggest a resolution to the paradox of algal blooms in oliogotrophic streams and rivers.

  13. DNA damage in bone marrow and blood cells of mice exposed to municipal sludge leachates.

    PubMed

    Tewari, Anamika; Dhawan, Alok; Gupta, Shrawan Kumar

    2006-05-01

    Leachates of municipal solid waste from unsecured disposal sites contaminate sources of potable water and affect human health. In the present study, we have used the Comet assay to evaluate the DNA damage in mice exposed to municipal sludge leachates. Ten percent leachates were prepared from municipal sludge obtained from two different disposal drains. Male Swiss albino mice were treated daily with 0.1-0.4 ml of the leachates by oral gavage for 15 days, and the DNA damage was evaluated in bone marrow and blood using Olive tail moment, % tail DNA, and tail length as measures of DNA damage. Physicochemical and metal analysis of the leachates detected the presence of cadmium, chromium, copper, nickel, lead, and zinc, as well as elevated concentrations of sulfate and nitrate. Both of the leachates produced significant dose-responsive increases in DNA damage in both mouse tissues. There were no significant differences in the responses for any of the Comet endpoints between tissues (for the same leachate sample) or between leachate samples (for the same tissue). The results of this study indicate that municipal waste leachates produce DNA damage in vivo.

  14. Study of cnidarian-algal symbiosis in the "omics" age.

    PubMed

    Meyer, Eli; Weis, Virginia M

    2012-08-01

    The symbiotic associations between cnidarians and dinoflagellate algae (Symbiodinium) support productive and diverse ecosystems in coral reefs. Many aspects of this association, including the mechanistic basis of host-symbiont recognition and metabolic interaction, remain poorly understood. The first completed genome sequence for a symbiotic anthozoan is now available (the coral Acropora digitifera), and extensive expressed sequence tag resources are available for a variety of other symbiotic corals and anemones. These resources make it possible to profile gene expression, protein abundance, and protein localization associated with the symbiotic state. Here we review the history of "omics" studies of cnidarian-algal symbiosis and the current availability of sequence resources for corals and anemones, identifying genes putatively involved in symbiosis across 10 anthozoan species. The public availability of candidate symbiosis-associated genes leaves the field of cnidarian-algal symbiosis poised for in-depth comparative studies of sequence diversity and gene expression and for targeted functional studies of genes associated with symbiosis. Reviewing the progress to date suggests directions for future investigations of cnidarian-algal symbiosis that include (i) sequencing of Symbiodinium, (ii) proteomic analysis of the symbiosome membrane complex, (iii) glycomic analysis of Symbiodinium cell surfaces, and (iv) expression profiling of the gastrodermal cells hosting Symbiodinium.

  15. Micro-structured surfaces for algal biofilm growth

    NASA Astrophysics Data System (ADS)

    Sathananthan, Suthamathy; Genin, Scott N.; Aitchison, J. Stewart; Allen, D. Grant

    2013-12-01

    It is well known that cells respond to structured surface cues that are on the micro/nanometer scale. Tissue engineering and bio-fouling fields have utilized the semiconductor device fabrication processes to make micro- and nanometer patterned surfaces to study animal cell tissue formation and to prevent algae attachment on marine surfaces respectively. In this paper we describe the use of micro-structured surfaces to study the attachment and growth of algal films. This paper gives an overview of how micro-structured surfaces are made for this purpose, how they are incorporated into a photo bioreactor and how this patterning influences the growth of an algal biofilm. Our results suggest that surface patterning with deeper V-groove patterns that are of the same size scale as the algal species has resulted in higher biomass productivity giving them a chance to embed and attach on the slope and flat surfaces whereas shallower size grooves and completely flat surfaces did not show this trend.

  16. Inter- and Intra-Chromosomal Aberrations in Human Cells Exposed in vitro to Space-like Radiations

    NASA Technical Reports Server (NTRS)

    Hada, Megumi; Cucinotta, F. A.; Gonda, S. R.; Wu, H.

    2005-01-01

    Energetic heavy ions pose a great health risk to astronauts in extended ISS and future exploration missions. High-LET heavy ions are particularly effective in causing various biological effects, including cell inactivation, genetic mutations and cancer induction. Most of these biological endpoints are closely related to chromosomal damage, which can be utilized as a biomarker for radiation insults. Previously, we had studied chromosome aberrations in human lymphocytes and fibroblasts induced by both low- and high-LET radiation using FISH and multicolor fluorescence in situ hybridization (mFISH) techniques. In this study, we exposed human cells in vitro to gamma rays and energetic particles of varying types and energies and dose rates, and analyzed chromosomal damages using the multicolor banding in situ hybridization (mBAND) procedure. Confluent human epithelial cells and lymphocytes were exposed to energetic heavy ions at NASA Space Radiation Laboratory (NSRL) at the Brookhaven National Laboratory (Upton, NY) or Cs-137 gamma radiation source at the Baylor College (Houston, TX). After colcemid and Calyculin A treatment, cells were fixed and painted with XCyte3 mBAND kit (MetaSystems) and chromosome aberrations were analyzed with mBAND analysis system (MetaSystems). With this technique, individually painted chromosomal bands on one chromosome allowed the identification of interchromosomal aberrations (translocation to unpainted chromosomes) and intrachromosomal aberrations (inversions and deletions within a single painted chromosome). The possible relationship between the frequency of inter- and intra-chromosomal exchanges and the track structure of radiation is discussed. The work was supported by the NASA Space Radiation Health Program.

  17. Effects of ozone and peroxone on algal separation via dispersed air flotation.

    PubMed

    Nguyen, Truc Linh; Lee, D J; Chang, J S; Liu, J C

    2013-05-01

    Effects of pre-oxidation on algal separation by dispersed air flotation were examined. Ozone (O3) and peroxone (O3 and H2O2) could induce cell lysis, release of intracellular organic matter (IOM), and mineralization of organic substances. Separation efficiency of algal cells improved when pre-oxidized. Total of 76.4% algal cells was separated at 40 mg/L of N-cetyl-N-N-N-trimethylammonium bromide (CTAB), while 95% were separated after 30-min ozonation. Pre-oxidation by ozone and peroxone also enhanced flotation separation efficiency of dissolved organic carbon (DOC), polysaccharide, and protein, in which peroxone process exerted more significantly than O3. Two main mechanisms were involved in flotation separation of unoxidized algal suspension, namely hydrophobic cell surface and cell flocculation resulting from CTAB adsorption. However, flocculation by CTAB was hindered for pre-oxidized algal suspensions. It implied that the compositional changes in extracellular organic matter (EOM) by pre-oxidation were more determined for flotation separation of pre-oxidized cells.

  18. Sustainable Algal Energy Production and Environmental Remediation

    SciTech Connect

    Cooke, William E.

    2012-07-14

    Overall, our results confirm that wild algal species sequester a wide range of organic and metal contaminants and excess nutrients (PAHs, trace metals, and nutrients) from natural waters, and suggest parameters that could be useful in predicting uptake rates for algae growing on an algal floway or other algal growth systems in the environment or in industrial processes. The implication for various fuel production processes differ with the detailed unit operations involved, and these results will be of use in the developing of scaling experiments for various types of engineering process designs.

  19. Induction of Poly(ADP-ribose) Polymerase in Mouse Bone Marrow Stromal Cells Exposed to 900 MHz Radiofrequency Fields: Preliminary Observations

    PubMed Central

    He, Qina; Sun, Yulong; Zong, Lin; Tong, Jian; Cao, Yi

    2016-01-01

    Background. Several investigators have reported increased levels of poly(ADP-ribose) polymerase-1 (PARP-1), a nuclear enzyme which plays an important role in the repair of damaged DNA, in cells exposed to extremely low dose ionizing radiation which does not cause measurable DNA damage. Objective. To examine whether exposure of the cells to nonionizing radiofrequency fields (RF) is capable of increasing messenger RNA of PARP-1 and its protein levels in mouse bone marrow stromal cells (BMSCs). Methods. BMSCs were exposed to 900 MHz RF at 120 μW/cm2 power intensity for 3 hours/day for 5 days. PARP-1 mRNA and its protein levels were examined at 0, 0.5, 1, 2, 4, 6, 8, and 10 hours after exposure using RT-PCR and Western blot analyses. Sham-exposed (SH) cells and those exposed to ionizing radiation were used as unexposed and positive control cells. Results. BMSCs exposed to RF showed significantly increased expression of PARP-1 mRNA and its protein levels after exposure to RF while such changes were not observed in SH-exposed cells. Conclusion. Nonionizing RF exposure is capable of inducing PARP-1. PMID:27190989

  20. Morphological changes among hippocampal dentate granule cells exposed to early kindling-epileptogenesis

    PubMed Central

    Singh, Shatrunjai P.; He, Xiaoping; McNamara, James O.; Danzer, Steve C.

    2013-01-01

    Temporal lobe epilepsy is associated with changes in the morphology of hippocampal dentate granule cells. These changes are evident in numerous models that are associated with substantial neuron loss and spontaneous recurrent seizures. By contrast, previous studies have shown that in the kindling model, it is possible to administer a limited number of stimulations sufficient to produce a lifelong enhanced sensitivity to stimulus evoked seizures without associated spontaneous seizures and minimal neuronal loss. Here we examined whether stimulation of the amygdala sufficient to evoke five convulsive seizures (class IV or greater on Racine’s scale) produce morphological changes similar to those observed in models of epilepsy associated with substantial cell loss. The morphology of GFP-expressing granule cells from Thy-1 GFP mice was examined either one day or one month after the last evoked seizure. Interestingly, significant reductions in dendritic spine density were evident one day after the last seizure, the magnitude of which had diminished by one month. Further, there was an increase in the thickness of the granule cell layer one day after the last evoked seizure, which was absent a month later. We also observed an increase in the area of the proximal axon, which again returned to control levels a month later. No differences in the number of basal dendrites were detected at either time point. These findings demonstrate that the early stages of kindling epileptogenesis produce transient changes in the granule cell body layer thickness, molecular layer spine density and axon proximal area, but do not produce striking rearrangements of granule cell structure. PMID:23893783

  1. Exploring the Utilization of Complex Algal Communities to Address Algal Pond Crash and Increase Annual Biomass Production for Algal Biofuels

    SciTech Connect

    Hamilton, Cyd E.

    2014-03-25

    This white paper briefly reviews the research literature exploring complex algal communities as a means of increasing algal biomass production via increased tolerance, resilience, and resistance to a variety of abiotic and biotic perturbations occurring within harvesting timescales. This paper identifies what data are available and whether more research utilizing complex communities is needed to explore the potential of complex algal community stability (CACS) approach as a plausible means to increase biomass yields regardless of ecological context and resulting in decreased algal-based fuel prices by reducing operations costs. By reviewing the literature for what we do and do not know, in terms of CACS methodologies, this report will provide guidance for future research addressing pond crash phenomena.

  2. Mutant quantity and quality in mammalian cells (AL) exposed to cesium-137 gamma radiation: effect of caffeine

    NASA Technical Reports Server (NTRS)

    McGuinness, S. M.; Shibuya, M. L.; Ueno, A. M.; Vannais, D. B.; Waldren, C. A.; Chatterjee, A. (Principal Investigator)

    1995-01-01

    We examined the effect of caffeine (1,3,7-trimethylxanthine) on the quantity and quality of mutations in cultured mammalian AL human-hamster hybrid cells exposed to 137Cs gamma radiation. At a dose (1.5 mg/ml for 16 h) that reduced the plating efficiency (PE) by 20%, caffeine was not itself a significant mutagen, but it increased by approximately twofold the slope of the dose-response curve for induction of S1- mutants by 137Cs gamma radiation. Molecular analysis of 235 S1- mutants using a series of DNA probes mapped to the human chromosome 11 in the AL hybrid cells revealed that 73 to 85% of the mutations in unexposed cells and in cells treated with caffeine alone, 137Cs gamma rays alone or 137Cs gamma rays plus caffeine were large deletions involving millions of base pairs of DNA. Most of these deletions were contiguous with the region of the MIC1 gene at 11p13 that encodes the S1 cell surface antigen. In other mutants that had suffered multiple marker loss, the deletions were intermittent along chromosome 11. These "complex" mutations were rare for 137Cs gamma irradiation (1/63 = 1.5%) but relatively prevalent (23-50%) for other exposure conditions. Thus caffeine appears to alter both the quantity and quality of mutations induced by 137Cs gamma irradiation.

  3. Activation of transcription factors in human bronchial epithelial cells exposed to aqueous extracts of mainstream cigarette smoke in vitro.

    PubMed

    Sekine, Takashi; Hirata, Tadashi; Mine, Toshiki; Fukano, Yasuo

    2016-01-01

    This study aimed to identify the most sensitive transcription factor activated by cigarette smoke extract (CSE) and to explore cigarette smoke components that have high biological activities in a cell-base assay. Previously, we found evidence that implicated 10 different transcription factors as having a high biological activity to CSE in vitro, based on the results of a comprehensive gene expression profile. For this study, luciferase reporter assays for each transcription factor were developed in two types of human bronchial epithelial cells: NCI-H292 and BEAS-2B cells. The results demonstrated that the nuclear factor erythroid 2-related factor 2 (NRF2)/anti-oxidant response element (ARE) pathway was the most sensitive in response to CSE. Consistently, hemo oxygenase-1 (HO-1), a downstream target gene of NRF2, was effectively up-regulated in BEAS-2B cells exposed to CSE. Moreover, among 1395 cigarette smoke components, naphthoquinones including 9,10-phenaotrenquinone, quinones, benzenediols and α, β-unsaturated carbonyls, were identified as major smoke components that contribute to activating the NRF2/ARE pathway, as indicated by the ARE-reporter assay in BEAS-2B cells. Taken together, NRF2 appears to be a key molecule in the CSE-induced cellular response, and the employed methodology is helpful for the analysis of molecular and cellular effects by CSE.

  4. Collagen Synthesis in Tenocytes, Ligament Cells and Chondrocytes Exposed to a Combination of Glucosamine HCl and Chondroitin Sulfate

    PubMed Central

    2007-01-01

    Clinical testing of the nutraceuticals glucosamine (glcN) and chondroitin sulfate (CS) has shown efficacy in providing relief from symptoms in osteoarthritic patients. In vitro and in vivo studies support existence of a synergistic relationship upregulating synthetic activity in chondrocytes. A combination of glcN and CS may also be useful as adjunct therapy in sports-related injuries if similar upregulation of collagen synthesis is elicited in accessory ligament and tendon joint tissue. Collagen and non-collagenous protein (NCP) synthesis in cultures of bovine tenocytes, ligament cells and chondrocytes exposed to glcN + CS were assayed by uptake of radiolabeled proline into collagenase-sensitive material. Assay of radiolabel in hydroxyproline (a specific marker for collagen synthesis) following HPLC isolation confirmed the specificity of the metabolic effect. Synthesis of total collagenase-sensitive material was maximally upregulated at physiologically obtainable doses of glcN + CS. Tissue response followed the sequence ligament cells (+69%) > chondrocytes (+56%) > tenocytes (+22%). Labeled hydroxyproline increased by 132% in ligament cells, 27% in tenocytes and 49% in epitendon cells after a 48 h exposure to 5 μg ml−1 glcN + 4 μg ml−1 CS. Low dose combinations of glcN and CS effectively stimulate in vitro collagen and NCP synthesis by ligament cells, tenocytes and chondrocytes. Hence, therapeutic use following accessory joint tissue trauma may help augment repair processes. PMID:17549239

  5. In vitro measurements of oxygen consumption rates in hTERT-RPE cells exposed to low levels of red light

    NASA Astrophysics Data System (ADS)

    Wigle, Jeffrey C.; Castellanos, Cherry C.

    2016-03-01

    Exposure to 2.88 J/cm2 of red light induces an adaptive response against a lethal pulse of 2.0 μm laser radiation in hTERT-RPE cells in vitro, but not in a knockdown mutant for vascular endothelial growth factor c (VEGF-C). The generally accepted initiation sequence for photobiomodulation is that absorption of red light by cytochome c oxidase (CCOX) of the electron transport chain increases the binding affinity of CCOX for O2 vs. nitric oxide (NO). This results in displacement of NO by O2 in the active site of CCOX, thereby increasing cellular respiration and intracellular ATP. We've previously reported that red-light exposure induces a small, but consistently reproducible, increase in NO levels in these cells. But the relative importance of NO and oxidative phosphorylation is unclear because little is known about the relative contributions of NO and ATP to the response. However, if NO dissociation from CCOX actually increases oxidative phosphorylation, one should see a corresponding increase in oxygen consumption. A Seahorse Extracellular Flux Analyzer was used to measure oxygen consumption rates (OCR) in normal and mutant cells as a proxy for oxidative phosphorylation. Both basal respiration and maximum respiration rates in normal cells are significantly higher than in the mutant. The normal cells have a significant amount of "excess capacity," whereas the VEGF-C(KD) have little or none. The OCR in exposed normal cells is lower than in unexposed cells when measured immediately after exposure. The exposures used for these experiments had no effect on the OCR in mutant cells.

  6. GENE EXPRESSION PROFILING OF NORMAL HUMAN BRONCHIAL EPITHELIAL CELLS EXPOSED TO TRIVALENT ARSENICALS AND DIMETHYLTHIOARSINIC ACID

    EPA Science Inventory

    Lung is a major target for arsenic carcinogenesis in humans. However, the carcinogenic mode of action of arsenicals is unknown. We investigated, in human bronchial epithelial (BEAS2B) cells, the effects of inorganic arsenic (iAsIII), monomethylarsonous acid (MMAIII), dimethylarsi...

  7. ACTIVATION OF THE EGF RECEPTOR SIGNALING PATHWAY IN HUMAN AIRWAY EPITHELIAL CELLS EXPOSED TO METALS

    EPA Science Inventory

    We have previously shown that exposure to combustion-derived metals rapidly (within 20 min) activated mitogen-activated protein kinases (MAPK), including extracellular signal-regulated kinase (ERK), in the human bronchial epithelial cell line BEAS. To study the mechanisms respons...

  8. Nanomimics of host cell membranes block invasion and expose invasive malaria parasites.

    PubMed

    Najer, Adrian; Wu, Dalin; Bieri, Andrej; Brand, Françoise; Palivan, Cornelia G; Beck, Hans-Peter; Meier, Wolfgang

    2014-12-23

    The fight against most infectious diseases, including malaria, is often hampered by the emergence of drug resistance and lack or limited efficacies of vaccines. Therefore, new drugs, vaccines, or other strategies to control these diseases are needed. Here, we present an innovative nanotechnological strategy in which the nanostructure itself represents the active substance with no necessity to release compounds to attain therapeutic effect and which might act in a drug- and vaccine-like dual function. Invasion of Plasmodium falciparum parasites into red blood cells was selected as a biological model for the initial validation of this approach. Stable nanomimics-polymersomes presenting receptors required for parasite attachment to host cells-were designed to efficiently interrupt the life cycle of the parasite by inhibiting invasion. A simple way to build nanomimics without postformation modifications was established. First, a block copolymer of the receptor with a hydrophobic polymer was synthesized and then mixed with a polymersome-forming block copolymer. The resulting nanomimics bound parasite-derived ligands involved in the initial attachment to host cells and they efficiently blocked reinvasion of malaria parasites after their egress from host cells in vitro. They exhibited efficacies of more than 2 orders of magnitude higher than the soluble form of the receptor, which can be explained by multivalent interactions of several receptors on one nanomimic with multiple ligands on the infective parasite. In the future, our strategy might offer interesting treatment options for severe malaria or a way to modulate the immune response.

  9. Testosterone Protects Mitochondrial Function and Regulates Neuroglobin Expression in Astrocytic Cells Exposed to Glucose Deprivation

    PubMed Central

    Toro-Urrego, Nicolas; Garcia-Segura, Luis M.; Echeverria, Valentina; Barreto, George E.

    2016-01-01

    Testosterone is a hormone that has been shown to confer neuroprotection from different insults affecting the central nervous system (CNS). Testosterone induces this protection by different mechanisms that include the activation of anti-apoptotic pathways that are directly implicated in neuronal survival. However, little attention has been devoted to its actions on glial cells. In the present study, we have assessed whether testosterone exerts protection in a human astrocyte cell model, the T98G cells. Our results indicate that testosterone improves cell survival and mitochondrial membrane potential and reduces nuclear fragmentation and reactive oxygen species (ROS) generation. These effects were accompanied by a positive regulation of neuroglobin, an oxygen-binding and sensor protein, which may serve as a regulator of ROS and nitrogen reactive species (NOS), and these protective effects of testosterone may be at least in part mediated by estradiol and DHT. In conclusion, these findings suggest that astroglia may mediate some of the protective actions of testosterone in the brain upon pathological conditions. PMID:27445795

  10. Photobiomodulation Protects and Promotes Differentiation of C2C12 Myoblast Cells Exposed to Snake Venom

    PubMed Central

    da Silva, Aline; Vieira, Rodolfo Paula; Mesquita-Ferrari, Raquel Agnelli; Cogo, José Carlos; Zamuner, Stella Regina

    2016-01-01

    Background Snakebites is a neglected disease and in Brazil is considered a serious health problem, with the majority of the snakebites caused by the genus Bothrops. Antivenom therapy and other first-aid treatments do not reverse local myonecrose which is the main sequel caused by the envenomation. Several studies have shown the effectiveness of low level laser (LLL) therapy in reducing local myonecrosis induced by Bothropic venoms, however the mechanism involved in this effect is unknown. In this in vitro study, we aimed to analyze the effect of LLL irradiation against cytotoxicity induced by Bothrops jararacussu venom on myoblast C2C12 cells. Methodology C2C12 were utilized as a model target and were incubated with B. jararacussu venom (12.5 μg/mL) and immediately irradiated with LLL at wavelength of red 685 nm or infrared 830 nm with energy density of 2.0, 4.6 and 7.0 J/cm2. Effects of LLL on cellular responses of venom-induced cytotoxicity were examined, including cell viability, measurement of cell damage and intra and extracellular ATP levels, expression of myogenic regulatory factors, as well as cellular differentiation. Results In non-irradiated cells, the venom caused a decrease in cell viability and a massive release of LDH and CK levels indicating myonecrosis. Infrared and red laser at all energy densities were able to considerably decrease venom-induced cytotoxicity. Laser irradiation induced myoblasts to differentiate into myotubes and this effect was accompanied by up regulation of MyoD and specially myogenin. Moreover, LLL was able to reduce the extracellular while increased the intracellular ATP content after venom exposure. In addition, no difference in the intensity of cytotoxicity was shown by non-irradiated and irradiated venom. Conclusion LLL irradiation caused a protective effect on C2C12 cells against the cytotoxicity caused by B. jararacussu venom and promotes differentiation of these cells by up regulation of myogenic factors. A modulatory

  11. Efficacy of human umbilical cord derived-mesenchymal stem cells in treatment of rat bone marrow exposed to gamma irradiation.

    PubMed

    Mousa, Hanaa S E; Shalaby, Sally M; Gouda, Zienab A; Ahmed, Fayza E; El-Khodary, Aisha A

    2017-03-01

    To assess the therapeutic effects of the human umbilical cord blood (hUCB) derived mesenchymal stem cells (MSCs) on rat bone marrow (BM) exposed to gamma rays, 3 groups (n=15 each) of adult male Wistar albino rats were utilized as follows: the 1st group received PBS (control group), the 2nd group was exposed to gamma rays 1.04Gy/min (R group) and the 3rd group exposed to same dose as RG and injected hUCB-MSCs. The BM of femurs was processed for histological and immunohistochemical staining with proliferating cell nuclear antigen antibody (PCNA), anti human CD105 and anti human CD34. Hb content, leukocytes and platelet counts were analyzed as well as fat cells and megakaryocytic counts. Also, the BM vascular spaces and the optical density of immunostaining for PCNA were analyzed. The leukocytes and platelet counts were significantly lower in the R (2.85±235.8; P=0.000 and 95.27±3.01; P=0.000 respectively) when compared with the control (10.40±443.2; P=0.000 and 430.18±20.28; P=0.000 respectively). The fat cell count was significantly higher in the R (36.55±1.83; P=0.000) than in control (7.64±0.61; P=0.000) and in R injected h-MSCs tissues (18.82±2.03; P=0.000). The megakaryocytic count was significantly higher in the R injected h-MSCs (5.36±0.310; P=0.000) than in control (2.82±0.263; P=0.000) and in the R BM (0.45±0.157; P=0.000). The vascular spaces were dilated and significantly increased in the R injected h-MSCs (50.10±2.40; P=0.000) than in control (33.36±1.01; P=0.000). The optical density of PCNA expression was significantly lower in R (0.18±0.11; P=0.005) than in control (0.41±0.40; P=0.005) and in R injected h-MSCs groups (0.30±0.17; P=0.005). The present study concluded that injection of hUCB-MSCs improves destructive effects of bone marrow induced by gamma radiation. Use of radio-protective agents during exposure is recommended.

  12. Gene expression profile of human lung epithelial cells chronically exposed to single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Chen, Dongquan; Stueckle, Todd A.; Luanpitpong, Sudjit; Rojanasakul, Yon; Lu, Yongju; Wang, Liying

    2015-01-01

    A rapid increase in utility of engineered nanomaterials, including carbon nanotubes (CNTs), has raised a concern over their safety. Based on recent evidence from animal studies, pulmonary exposure of CNTs may lead to nanoparticle accumulation in the deep lung without effective clearance which could interact with local lung cells for a long period of time. Physicochemical similarities of CNTs to asbestos fibers may contribute to their asbestos-like carcinogenic potential after long-term exposure, which has not been well addressed. More studies are needed to identify and predict the carcinogenic potential and mechanisms for promoting their safe use. Our previous study reported a long-term in vitro exposure model for CNT carcinogenicity and showed that 6-month sub-chronic exposure of single-walled carbon nanotubes (SWCNT) causes malignant transformation of human lung epithelial cells. In addition, the transformed cells induced tumor formation in mice and exhibited an apoptosis resistant phenotype, a key characteristic of cancer cells. Although the potential role of p53 in the transformation process was identified, the underlying mechanisms of oncogenesis remain largely undefined. Here, we further examined the gene expression profile by using genome microarrays to profile molecular mechanisms of SWCNT oncogenesis. Based on differentially expressed genes, possible mechanisms of SWCNT-associated apoptosis resistance and oncogenesis were identified, which included activation of pAkt/p53/Bcl-2 signaling axis, increased gene expression of Ras family for cell cycle control, Dsh-mediated Notch 1, and downregulation of apoptotic genes BAX and Noxa. Activated immune responses were among the major changes of biological function. Our findings shed light on potential molecular mechanisms and signaling pathways involved in SWCNT oncogenic potential.

  13. The Morphological and Molecular Changes of Brain Cells Exposed to Direct Current Electric Field Stimulation

    PubMed Central

    Pelletier, Simon J.; Lagacé, Marie; St-Amour, Isabelle; Arsenault, Dany; Cisbani, Giulia; Chabrat, Audrey; Fecteau, Shirley; Lévesque, Martin

    2015-01-01

    Background: The application of low-intensity direct current electric fields has been experimentally used in the clinic to treat a number of brain disorders, predominantly using transcranial direct current stimulation approaches. However, the cellular and molecular changes induced by such treatment remain largely unknown. Methods: Here, we tested various intensities of direct current electric fields (0, 25, 50, and 100V/m) in a well-controlled in vitro environment in order to investigate the responses of neurons, microglia, and astrocytes to this type of stimulation. This included morphological assessments of the cells, viability, as well as shape and fiber outgrowth relative to the orientation of the direct current electric field. We also undertook enzyme-linked immunosorbent assays and western immunoblotting to identify which molecular pathways were affected by direct current electric fields. Results: In response to direct current electric field, neurons developed an elongated cell body shape with neurite outgrowth that was associated with a significant increase in growth associated protein-43. Fetal midbrain dopaminergic explants grown in a collagen gel matrix also showed a reorientation of their neurites towards the cathode. BV2 microglial cells adopted distinct morphological changes with an increase in cyclooxygenase-2 expression, but these were dependent on whether they had already been activated with lipopolysaccharide. Finally, astrocytes displayed elongated cell bodies with cellular filopodia that were oriented perpendicularly to the direct current electric field. Conclusion: We show that cells of the central nervous system can respond to direct current electric fields both in terms of their morphological shape and molecular expression of certain proteins, and this in turn can help us to begin understand the mechanisms underlying the clinical benefits of direct current electric field. PMID:25522422

  14. Müller cell gliotic response in the retina of the newts exposed to real and simulated microgravity

    NASA Astrophysics Data System (ADS)

    Grigoryan, Eleonora N.; Poplinskaya, Valentina; Domaratskaya; Aleinikova, Karina; Novikova, Julia; Anton, Hermann J.; Almeida, Eduardo

    The effects of real and simulated microgravity on the eye tissue regeneration of newts (Pl. waltli) after lens and/or retina removal were investigated. Changes in Müller glial cells in the retina of eyes regenerating after lens extirpation were detected in newts exposed to clinostat-ing. The cells were hypertrophied, and their processes thickened. Such changes were viewed as specific of reactive gliosis [1]. Later experiments onboard the Russian biosatellite Bion-11 showed similar changes in the retinas of newts regenerating after a two-week spaceflight. In the Bion-11 animals, GFAP, the major structural protein of macroglial cells was found to be up-regulated [2]. In more recent experiments onboard Foton-2 (2005) and Foton-M3 (2007), GFAP expression in retinas of space-flown, ground control (kept at 1 g), and basal control (sacrificed on launch day) newts was quantified, using microscopy, immunohistochemistry, and digital image analysis. It was found that Müller cell processes of non-operated animals dis-u played low GFAP immunolabeling. A low level of immunoreactivity was also observed in basal controls. In contrast, retinas of space-flown animals showed greater GFAP immunoreactivity associated with both an increased cell number and a higher density of intermediate filaments [3]. This, in turn, was accompanied by up-regulation of stress protein (HSP90) and growth factor (FGF2) expressions. It can be postulated that such a response of Müller cells was to mitigate the retinal stress in newts exposed to microgravity. Although the exact mechanisms remain unknown, it can be hypothesized that GFAP up-regulation is mediated by HSPs and growth factors, particularly by FGF2. Taken together, these data suggest that the retinal population of macroglial cells is sensitive to gravity changes and that in space it can react by enhancing its neuroprotective function. [1] Grigoryan E.N., Anton H.J., Mitashov V.I. Adv. Space Res. 1998. V. 22. N.2. P. 293-301. [2] Grigoryan E

  15. Development of a rotating algal biofilm growth system for attached microalgae growth with in situ biomass harvest.

    PubMed

    Gross, Martin; Henry, Wesley; Michael, Clayton; Wen, Zhiyou

    2013-12-01

    This work aimed to develop a rotating algal biofilm (RAB) cultivation system that can be widely adopted by microalgae producers for easy biomass harvest. Algal cells were grown on the surface of a material rotating between nutrient-rich liquid and CO2-rich gaseous phase. Scrapping biomass from the attached surface avoided the expensive harvest operations such as centrifugation. Among various attachment materials, cotton sheet resulted in best algal growth, durability, and cost effectiveness. A lab-scale RAB system was further optimized with harvest frequency, rotation speed, and CO2 levels. The algal biomass from the RAB system had a similar water content as that in centrifuged biomass. An open pond raceway retrofitted with a pilot-scale RAB system resulted in a much higher biomass productivity when compared to a control open pond. Collectively, the research shows that the RAB system is an efficient algal culture system for easy biomass harvest with enhanced biomass productivity.

  16. Yearlong evaluation of performance and durability of a pilot-scale Revolving Algal Biofilm (RAB) cultivation system.

    PubMed

    Gross, Martin; Wen, Zhiyou

    2014-11-01

    Current algal cultivation has been mainly performed in open ponds or photobioreactors in which algal cells are suspended and harvested through flocculation and centrifugation. A unique attachment based Revolving Algal Biofilm (RAB) cultivation system was recently developed for easy biomass harvest with enhanced biomass productivity. The objective of this research was to evaluate the performance (durability, algal growth, and the geometry) of the RAB system at pilot-scale. A yearlong test of the RAB system was successfully conducted at a greenhouse facility at Boone, Iowa, USA. The RAB resulted in an average of 302% increase in biomass productivity compared to a standard raceway pond, with a maximum biomass productivity (ash free) of 18.9 g/m(2)-day being achieved. The RAB with a vertical configuration generated higher productivity than the triangular RAB. Collectively, the research shows that the RAB as an efficient algal culture system has great potential for being deployed at commercial scale.

  17. Renal Cell Carcinomas in Vinylidene Chloride Exposed Male B6C3F1 Mice Are Characterized by Oxidative Stress and TP53 Pathway Dysregulation

    PubMed Central

    Hayes, Schantel A.; Pandiri, Arun R.; Ton, Thai-vu T.; Hong, Hue-Hua L.; Clayton, Natasha P.; Shockley, Keith R.; Peddada, Shyamal D.; Gerrish, Kevin; Wyde, Michael; Sills, Robert C.; Hoenerhoff, Mark J.

    2015-01-01

    Vinylidene Chloride (VDC) has been widely used in the production of plastics and flame retardants. Exposure of B6C3F1 mice to VDC in the 2-year National Toxicology Program carcinogenicity bioassay resulted in a dose-dependent increases in renal cell hyperplasia, adenoma, and carcinoma (RCCs). Among those differentially expressed genes between controls and RCC from VDC-exposed mice, there was an overrepresentation of genes from pathways associated with chronic xenobiotic and oxidative stress, as well as c-Myc overexpression and dysregulation of TP53 cell cycle checkpoint and DNA damage repair pathways in RCC. Trend analysis comparing RCC, VDC-exposed kidney, and chamber control kidney showed a conservation of pathway dysregulation in terms of overrepresentation of xenobiotic and oxidative stress, and DNA damage and cell cycle checkpoint pathways in both VDC-exposed kidney and RCC, suggesting that these mechanisms play a role in the pathogenesis of RCC in VDC-exposed mice. PMID:26682919

  18. Study on cytotoxicity and structure-activity relationship of HL-7702 cell exposed to naphthoquinones.

    PubMed

    Guo, Jing; Song, Wenhua; Ding, Feng; Zhang, Jinyang; Sun, Zengtian

    2012-05-01

    The acute cytotoxicities of six naphthoquinone compounds, including Atovaquone, Buparvaquone, Menadione, 2-acetoxy-1,4-naphthoquinone and 2-ethoxy-1,4-naphthoquinone, to HL-7702 cells were determined. The results showed that the toxicities of these naphthoquinones were characterized by a steep response pattern except for 2-hydroxy-1,4-naphthoquinone. Meanwhile, the cellular injuries were unrecoverable. Several molecular descriptors, such as the octanol-water partition coefficients (LogP), diameter (Dia) and topological index (TIndx), played an important role in the toxicity of naphthoquinones to HL-7702 cell. Our results provide a foundation for further investigation using 3D-QSAR and HQSAR to evaluate the aquatic ecological risk and the possible mechanisms of toxicity of naphthoquinones.

  19. DNA Repair in Human Cells Exposed to Combinations of Carcinogenic Agents

    SciTech Connect

    Setlow, R. B.; Ahmed, F. E.

    1980-01-01

    Normal human and XP2 fibroblasts were treated with UV plus UV-mimetic chemicals. The UV dose used was sufficient to saturate the UV excision repair system. Excision repair after combined treatments was estimated by unscheduled DNA synthesis, BrdUrd photolysis, and the loss of sites sensitive to a UV specific endonuclease. Since the repair of damage from UV and its mimetics is coordinately controlled we expected that there would be similar rate-limiting steps in the repair of UV and chemical damage and that after a combined treatment the total amount of repair would be the same as from UV or the chemicals separately. The expectation was not fulfilled. In normal cells repair after a combined treatment was additive whereas in XP cells repair after a combined treatment was usually less than after either agent separately. The chemicals tested were AAAF, DMBA-epoxide, 4NQO, and ICR-170.

  20. Distribution of Chromosome Breakpoints in Human Epithelial Cells Exposed to Low- and High-LET Radiation

    NASA Technical Reports Server (NTRS)

    Hada, Megumi; Zhang, Ye; Cucinotta, Francis A.; Feiveson, Alan; Wu, Honglu

    2010-01-01

    Low-and high-LET radiations produced distinct breakpoint distributions. The difference of the breakpoint distributions between low-and high-LET only appeared in break ends involved in interchromosome exchanges. The breakpoint distributions for break ends participating in intrachromosome exchanges were similar. Gene-rich regions do not necessarily have more chromosome breaks. High-LET appeared to produce long live (data not shown) or longer live breaks that can migrate a longer distance before rejoining with other breaks. Domains occupied by different segments of the chromosomes may be responsible for the breakpoint distribution. The dose responses for interchromosomal exchanges were linear in all four exposures. However, the dose response for intrachromosomal exchanges were none linear. Increasing dose of high dose rate exposure (Fe-ions or -rays) increase the fraction of cells with intrachromosome aberrations, whereas increasing dose of low dose rate exposure (neutrons or -rays) does not affect the fraction of cells with intrachromosome aberrations.

  1. Proteomic studies in zebrafish liver cells exposed to the brominated flame retardants HBCD and TBBPA.

    PubMed

    Kling, Peter; Förlin, Lars

    2009-10-01

    Proteomic effect screening in zebrafish liver cells was performed to generate hypotheses regarding single and mixed exposure to the BFRs HBCD and TBBPA. Responses at sublethal exposure were analysed by two-dimensional gel electrophoresis followed by MALDI-TOF and FT-ICR protein identification. Mixing of HBCD and TBBPA at sublethal doses of individual substances seemed to increase toxicity. Proteomic analyses revealed distinct exposure-specific and overlapping responses suggesting novel mechanisms with regard to HBCD and TBBPA exposure. While distinct HBCD responses were related to decreased protein metabolism, TBBPA revealed effects related to protein folding and NADPH production. Overlapping responses suggest increased gluconeogenesis (GAPDH and aldolase) while distinct mixture effects suggest a pronounced NADPH production and changes in proteins related to cell cycle control (prohibitin and crk-like oncogene). We conclude that mixtures containing HBCD and TBBPA may result in unexpected effects highlighting proteomics as a sensitive tool for detecting and hypothesis generation of mixture effects.

  2. Analysis of lysosomal membrane proteins exposed to melanin in HeLa cells

    PubMed Central

    2016-01-01

    Objectives There have been developed to use targeting ability for antimicrobial, anticancerous, gene therapy and cosmetics through analysis of various membrane proteins isolated from cell organelles. Methods It was examined about the lysosomal membrane protein extracted from lysosome isolated from HeLa cell treated by 100 ppm melanin for 24 hours in order to find associated with targeting ability to melanin using by 2-dimensional electrophoresis. Results The result showed 14 up-regulated (1.5-fold) and 13 down-regulated (2.0-fold) spots in relation to melanin exposure. Conclusions It has been found that lysosomal membrane proteins are associated with melanin to decolorize and quantity through cellular activation of lysosome. PMID:27158002

  3. Genotoxic Changes to Rodent Cells Exposed in Vitro to Tungsten, Nickel, Cobalt and Iron

    DTIC Science & Technology

    2014-03-10

    available gene chips. The results obtained were compared to untreated controls and tantalum -treated cells. Tantalum has been shown to be an inert non...serum mutagenicity studies with rats implanted with depleted uranium or tantalum pellets. Mutagenesis 1998, 13, 643–648. 6. McClain, D.E.; Benson, K.A...bone and tantalum , niobium or commercially pure titanium. Biomaterials 1990, 11, 277–280. 32. Fan, J.B.; Gunderson, K.L.; Bibikova, M.; Yeakley, J.M

  4. In vivo sulfhydryl distribution in brown cells of Mercenaria mercenaria exposed to cadmium

    SciTech Connect

    Zaroogian, G.

    1995-12-31

    Brown cells are found in the red glands of Mercenaria mercenaria (Bivalvia) and have a role in detoxification. Brown cell involvement in metal detoxification is due in part to endogenous glutathione (GSH) and protein bound sulfhydryl (PBSH). During treatment of Mercenaria with 0.5 and 1.0 ppm Cd{sup 2+}, brown cells were analyzed for total sulfhydryl (TSH), PBSH, non-protein bound sulfhydryl (NPSH) and GSH after 0.25, 1, 2, 3, 6, 12 and 20 days. Trend analyses indicated that treatment with 0.5 ppm Cd{sup 2+} caused a continuous increase in PBSH/TSH, whereas NPSH/TSH did not appear to change during 20 days treatment. The GSH/NPSH ratio increased significantly (P<0.01) for 6 days, followed by a significant (P<0.01) continuous decrease to day 20. Treatment with 1.0 ppm Cd{sup 2+} caused an increase in NPSH/TSH during the first 3 days, after which the ratio remained fairly constant to day 20, whereas PBSH/TSH decreased today 2, increased to day 3 and remained unchanged to day 20. The GSH/NPSH ratio remained fairly constant for the first 12 days after which it increased significantly (P<0.01). Histopathological examination after treatment with 1.0 ppm Cd 2{sup +} indicated darkening of the lysosomes during the first 2 days, followed by extensive brown cell sloughing into the tubule lumen and the abundance of small lysosomes at day 3. Sloughing and small lysosome formation continued to a lesser extent to day 20 when granulocyte infiltration and necrosis of the intertubular connective tissue occurred. The data indicate that GSH is more resistant to fluctuations than PBSH which suggests a more rapid synthesis or turnover rate for GSH. The ratio of GSH to PBSH has potential for a biomarker of cadmium exposure and health of Mercenaria.

  5. Extracellular signal-regulated kinases 1 and 2 activation in endothelial cells exposed to cyclic strain

    NASA Technical Reports Server (NTRS)

    Ikeda, M.; Takei, T.; Mills, I.; Kito, H.; Sumpio, B. E.

    1999-01-01

    The aim of this study was to determine whether extracellular signal-regulated kinases 1/2 (ERK1/ERK2) are activated and might play a role in enhanced proliferation and morphological change induced by strain. Bovine aortic endothelial cells (BAEC) were subjected to an average of 6 or 10% strain at a rate of 60 cycles/min for up to 4 h. Cyclic strain caused strain- and time-dependent phosphorylation and activation of ERK1/ERK2. Peak phosphorylation and activation of ERK1/ERK2 induced by 10% strain were at 10 min. A specific ERK1/ERK2 kinase inhibitor, PD-98059, inhibited phosphorylation and activation of ERK1/ERK2 but did not inhibit the increased cell proliferation and cell alignment induced by strain. Treatment of BAEC with 2,5-di-tert-butyl-1, 4-benzohydroquinone, to deplete inositol trisphosphate-sensitive calcium storage, and gadolinium chloride, a Ca2+ channel blocker, did not inhibit the activation of ERK1/ERK2. Strain-induced ERK1/ERK2 activation was partly inhibited by the protein kinase C inhibitor calphostin C and completely inhibited by the tyrosine kinase inhibitor genistein. These data suggest that 1) ERK1/ERK2 are not critically involved in the strain-induced cell proliferation and orientation, 2) strain-dependent activation of ERK1/ERK2 is independent of intracellular and extracellular calcium mobilization, and 3) protein kinase C activation and tyrosine kinase regulate strain-induced activation of ERK1/ERK2.

  6. Changes in protein expression of U937 and Jurkat cells exposed to nanosecond pulsed electric fields

    NASA Astrophysics Data System (ADS)

    Moen, Erick K.; Roth, Caleb C.; Cerna, Caesar; Estalck, Larry; Wilmink, Gerald; Ibey, Bennett L.

    2013-02-01

    Application of nanosecond pulsed electric fields (nsPEF) to various biological cell lines has been to shown to cause many diverse effects, including poration of the plasma membrane, depolarization of the mitochondrial membrane, blebbing, apoptosis, and intracellular calcium bursts. The underlying mechanism(s) responsible for these diverse responses are poorly understood. Of specific interest in this paper are the long-term effects of nsPEF on cellular processes, including the regulation of genes and production of proteins. Previous studies have reported transient activation of select signaling pathways involving mitogen-activated protein kinases (MAPKs), protein phosphorylation and downstream gene expression following nsPEF application. We hypothesize that nsPEF represents a unique stimulus that could be used to externally modulate cellular processes. To validate our hypothesis, we performed a series of cuvette-based exposures at 10 and 600ns pulse widths using a custom Blumlien line pulser system. We measured acute changes in the plasma membrane structure using flow cytometry by tracking phosphatidylserine externalization via FITC-Annexin V labeling and poration via propidium iodide uptake. We then compared these results to viability of the cells at 24 hours post exposure using MTT assay and changes in the MAPK family of proteins at 8 hours post-exposure using Luminex assay. By comparing exposures at 10 and 600ns duration, we found that most MAPK family-protein expression increased in Jurkat and U937 cell lines following exposure and compared well with drops in viability and changes in plasma membrane asymmetry. What proved interesting is that some MAPK family proteins (e.g. p53, STAT1), were expressed in one cell line, but not the other. This difference may point to an underlying mechanism for observed difference in cellular sensitivity to nsPEFinduced stresses.

  7. Disruption of cardiogenesis in human embryonic stem cells exposed to trichloroethylene.

    PubMed

    Jiang, Yan; Wang, Dan; Zhang, Guoxing; Wang, Guoqing; Tong, Jian; Chen, Tao

    2016-11-01

    Trichloroethylene (TCE) is ubiquitous in our living environment, and prenatal exposure to TCE is reported to cause congenital heart disease in humans. Although multiple studies have been performed using animal models, they have limited value in predicting effects on humans due to the unknown species-specific toxicological effects. To test whether exposure to low doses of TCE induces developmental toxicity in humans, we investigated the effect of TCE on human embryonic stem cells (hESCs) and cardiomyocytes (derived from the hESCs). In the current study, hESCs cardiac differentiation was achieved by using differentiation medium consisting of StemPro-34. We examined the effects of TCE on cell viability by cell growth assay and cardiac inhibition by analysis of spontaneously beating cluster. The expression levels of genes associated with cardiac differentiation and Ca(2+) channel pathways were measured by immunofluorescence and qPCR. The overall data indicated the following: (1) significant cardiac inhibition, which was characterized by decreased beating clusters and beating rates, following treatment with low doses of TCE; (2) significant up-regulation of the Nkx2.5/Hand1 gene in cardiac progenitors and down regulation of the Mhc-7/cTnT gene in cardiac cells; and (3) significant interference with Ca(2+) channel pathways in cardiomyocytes, which contributes to the adverse effect of TCE on cardiac differentiation during early embryo development. Our results confirmed the involvement of Ca(2+) turnover network in TCE cardiotoxicity as reported in animal models, while the inhibition effect of TCE on the transition of cardiac progenitors to cardiomyocytes is unique to hESCs, indicating a species-specific effect of TCE on heart development. This study provides new insight into TCE biology in humans, which may help explain the development of congenital heart defects after TCE exposure. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1372-1380, 2016.

  8. Differential effects of antipsychotics on the development of rat oligodendrocyte precursor cells exposed to cuprizone.

    PubMed

    Xu, Haiyun; Yang, Hong-Ju; Li, Xin-Min

    2014-03-01

    Cuprizone (CPZ) is a copper-chelating agent and has been shown to induce white matter damage in mice and rats. The compromised white matter and oligodendrocytes (OLs) respond to some antipsychotics in vivo. However, little is known about the effects of antipsychotics on cultured OLs in the presence of CPZ. The aim of this study was to examine effects of some antipsychotics on developing OLs in the presence of CPZ. Oligodendrocyte progenitor cells (OPCs) were prepared from rat embryos; OLs at different developing stages were labeled with specific antibodies; levels of CNP and MBP proteins in mature OLs were assessed by Western-blot analysis; malondialdehyde (MDA) levels and activity of catalase were evaluated as well for an assessment of oxidative stress and antioxidative status. In immunofluorescent staining, CPZ was shown to inhibit the differentiation of cultured OPCs into O4-positive cells, reduce the maturation of O4-positive cells into CNP- and MBP-positive cells, and decrease levels of CNP and MBP in mature OLs. These inhibitory effects of CPZ were ameliorated by clozapine and quetiapine (QUE), but not by haloperidol and olanzapine. Further experiments were performed to explore the mechanism of the protective effects of QUE. QUE attenuated the decreases in CNP and MBP in CPZ-treated OLs, and blocked the CPZ-induced increase in MDA and decrease in catalase activity in cultured OLs. These results are relevant to the pathophysiology and treatment of schizophrenia considering the aberrant white matter development and evidence suggesting the derangement of the oxidant and antioxidant defense system in some of the patients with schizophrenia.

  9. Persistent visceral allodynia in rats exposed to colorectal irradiation is reversed by mesenchymal stromal cell treatment.

    PubMed

    Durand, Christelle; Pezet, Sophie; Eutamène, Hélène; Demarquay, Christelle; Mathieu, Noëlle; Moussa, Lara; Daudin, Rachel; Holler, Valérie; Sabourin, Jean-Christophe; Milliat, Fabien; François, Agnès; Theodorou, Vassilia; Tamarat, Radia; Benderitter, Marc; Sémont, Alexandra

    2015-08-01

    Each year, millions of people worldwide are treated for primary or recurrent pelvic malignancies, involving radiotherapy in almost 50% of cases. Delayed development of visceral complications after radiotherapy is recognized in cancer survivors. Therapeutic doses of radiation may lead to the damage of healthy tissue around the tumor and abdominal pain. Because of the lack of experimental models, the underlying mechanisms of radiation-induced long-lasting visceral pain are still unknown. This makes managing radiation-induced pain difficult, and the therapeutic strategies proposed are mostly inefficient. The aim of our study was to develop an animal model of radiation-induced visceral hypersensitivity to (1) analyze some cellular and molecular mechanisms involved and (2) to test a therapeutic strategy using mesenchymal stromal cells (MSCs). Using a single 27-Grays colorectal irradiation in rats, we showed that such exposure induces a persistent visceral allodynia that is associated with an increased spinal sensitization (enhanced p-ERK neurons), colonic neuroplasticity (as increased density of substance P nerve fibers), and colonic mast cell hyperplasia and hypertrophy. Mast cell stabilization by ketotifen provided evidence of their functional involvement in radiation-induced allodynia. Finally, intravenous injection of 1.5 million MSCs, 4 weeks after irradiation, induced a time-dependent reversion of the visceral allodynia and a reduction of the number of anatomical interactions between mast cells and PGP9.5+ nerve fibers. Moreover, unlike ketotifen, MSC treatment has the key advantage to limit radiation-induced colonic ulceration. This work provides new insights into the potential use of MSCs as cellular therapy in the treatment of pelvic radiation disease.

  10. Formation of disinfection byproducts from chlor(am)ination of algal organic matter.

    PubMed

    Yang, Xin; Guo, Wanhong; Shen, Qianqian

    2011-12-15

    Algal cells and extracellular organic matter (EOM) of two algae species, Microcystis aeruginosa (blue-green algae) and Chlorella vulgaris (green algae), were characterized. The low specific UV absorbance (SUVA) values of EOM and cells from both algae species indicated the very hydrophilic nature of algal materials. Fluorescence excitation-emission matrix showed that algal EOM and cells were enriched with protein-like and soluble microbial by-product-like matters. The formation potential of a variety of disinfection by-products (DBPs) during chlorination and chloramination of algal cells and EOM were evaluated. Algal cells and EOM of Microcystis and Chlorella exhibited a high potential for DBP formation. Yields of total DBPs varied with the algae cultivation age. Cellular materials contributed more to DBP formation than EOM. The presence of bromide led to higher concentrations of total trihalomethanes (THMs), haloacetonitriles (HANs), and halonitromethanes (HNMs). Bromide also shifted the DBPs to brominated ones. Bromine incorporation was higher in HNMs than in THMs and HANs. Compared to natural organic matter, algae under bloom seasons can contribute significantly to the DBP precursor pool.

  11. Cord blood dendritic cell subsets in African newborns exposed to Plasmodium falciparum in utero.

    PubMed

    Breitling, Lutz P; Fendel, Rolf; Mordmueller, Benjamin; Adegnika, Ayola A; Kremsner, Peter G; Luty, Adrian J F

    2006-10-01

    Placental Plasmodium falciparum infection affects birth outcomes and sensitizes fetal lymphocytes to parasite antigens. We assessed the influence of maternal P. falciparum infection on fetal myeloid dendritic cells (mDC) and plasmacytoid dendritic cells (pDC), analyzing the cord blood of offspring of Gabonese mothers with different infection histories. Cord blood from newborns of mothers with malarial infection at delivery had significantly more mDC than that from nonexposed newborns (P = 0.028) but mDC and pDC HLA-DR expression was unrelated to maternal infection history. Independently of these findings, cord blood mDC and pDC numbers declined significantly as a function of increasing maternal age (P = 0.029 and P = 0.033, respectively). The inducible antigen-specific interleukin-10-producing regulatory-type T-cell population that we have previously detected in cord blood of newborns with prolonged in utero exposure to P. falciparum may directly reflect the altered DC numbers in such neonates, while the maintenance of cord blood DC HLA-DR expression contrasts with that of DC from P. falciparum malaria patients.

  12. Cord Blood Dendritic Cell Subsets in African Newborns Exposed to Plasmodium falciparum In Utero

    PubMed Central

    Breitling, Lutz P.; Fendel, Rolf; Mordmueller, Benjamin; Adegnika, Ayola A.; Kremsner, Peter G.; Luty, Adrian J. F.

    2006-01-01

    Placental Plasmodium falciparum infection affects birth outcomes and sensitizes fetal lymphocytes to parasite antigens. We assessed the influence of maternal P. falciparum infection on fetal myeloid dendritic cells (mDC) and plasmacytoid dendritic cells (pDC), analyzing the cord blood of offspring of Gabonese mothers with different infection histories. Cord blood from newborns of mothers with malarial infection at delivery had significantly more mDC than that from nonexposed newborns (P = 0.028) but mDC and pDC HLA-DR expression was unrelated to maternal infection history. Independently of these findings, cord blood mDC and pDC numbers declined significantly as a function of increasing maternal age (P = 0.029 and P = 0.033, respectively). The inducible antigen-specific interleukin-10-producing regulatory-type T-cell population that we have previously detected in cord blood of newborns with prolonged in utero exposure to P. falciparum may directly reflect the altered DC numbers in such neonates, while the maintenance of cord blood DC HLA-DR expression contrasts with that of DC from P. falciparum malaria patients. PMID:16988249

  13. Caffeic acid reduces the viability and migration rate of oral carcinoma cells (SCC-25) exposed to low concentrations of ethanol.

    PubMed

    Dziedzic, Arkadiusz; Kubina, Robert; Kabała-Dzik, Agata; Wojtyczka, Robert D; Morawiec, Tadeusz; Bułdak, Rafał J

    2014-10-17

    Alcohol increases the risk of carcinoma originated from oral epithelium, but the biological effects of ultra-low doses of ethanol on existing carcinoma cells in combination with natural substances are still unclear. A role for ethanol (EtOH), taken in small amounts as an ingredient of some beverages or mouthwashes to change the growth behavior of established squamous cell carcinoma, has still not been examined sufficiently. We designed an in vitro study to determine the effect of caffeic acid (CFA) on viability and migration ability of malignant oral epithelial keratinocytes, exposed to ultra-low concentrations (maximum 100 mmol/L) EtOH. MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-dimethyltetrazolium bromide) and LDH (lactate dehydrogenase) assays were used to assess the cytotoxic effect of EtOH/CFA and the viability of squamous carcinoma SCC-25 cells (ATCC CRL-1628, mobile part of the tongue). Tested EtOH concentrations were: 2.5, 5, 10, 25, 50, and 100 mmol/L, along with an equal CFA concentration of 50 μmol/L. Carcinoma cells' migration was investigated by monolayer "wound" healing assay. We demonstrated that very low concentrations of EtOH ranging between 2.5 and 10 mmol/L may induce the viability of oral squamous cell carcinoma cells, while the results following addition of CFA reveal an antagonistic effect, attenuating pro-proliferative EtOH activity. The migration rate of oral squamous carcinoma cells can be significantly inhibited by the biological activity of caffeic acid.

  14. Two coexisting tank bromeliads host distinct algal communities on a tropical inselberg.

    PubMed

    Carrias, J-F; Céréghino, R; Brouard, O; Pélozuelo, L; Dejean, A; Couté, A; Corbara, B; Leroy, C

    2014-09-01

    The tank bromeliads Aechmea aquilega (Salisb.) and Catopsis berteroniana (Schultes f.) coexist on a sun-exposed Neotropical inselberg in French Guiana, where they permit conspicuous freshwater pools to form that differ in size, complexity and detritus content. We sampled the algal communities (both eukaryotic and cyanobacterial taxa, including colourless forms) inhabiting either A. aquilega (n = 31) or C. berteroniana (n = 30) and examined differences in community composition and biomass patterns in relation to several biotic and abiotic variables. Chlorella sp. and Bumilleriopsis sp. were the most common taxa and dominated the algal biomass in A. aquilega and C. berteroniana, respectively. Using a redundancy analysis, we found that water volume, habitat complexity and the density of phagotrophic protozoa and collector-gatherer invertebrates were the main factors explaining the distribution of the algal taxa among the samples. Hierarchical clustering procedures based on abundance and presence/absence data clearly segregated the samples according to bromeliad species, revealing that the algal communities in the smaller bromeliad species were not a subset of the communities found in the larger bromeliad species. We conclude that, even though two coexisting tank bromeliad populations create adjacent aquatic habitats, each population hosts a distinct algal community. Hence, bromeliad diversity is thought to promote the local diversity of freshwater algae in the Neotropics.

  15. Compounds associated with algal surfaces mediate epiphytic colonization of the marine macroalga Fucus vesiculosus.

    PubMed

    Lachnit, Tim; Fischer, Matthias; Künzel, Sven; Baines, John F; Harder, Tilmann

    2013-05-01

    The macroalga Fucus vesiculosus carries a specific community of surface bacteria. To identify chemical compounds that possibly mediate abundance and community composition of algae-associated bacteria, we tested the effect of surface-available algal compounds on bacterial settlement and community composition under field conditions. Compounds on algal thalli were separated from the surface by extraction with organic solvents and investigated on growth inhibition and settlement of bacterial isolates. Based on in vitro data, partially purified extract fractions were then exposed to bacterial colonizers in vivo followed by bacterial enumeration and community analysis. The polar fraction of the algal surface extract revealed a significant profouling effect for Vibrionales, whereas the nonpolar fraction - containing the xanthophyll pigment fucoxanthin and other unidentified nonpolar surface compounds - revealed a significant 80% reduction of surface colonizing bacteria. The analysis of bacterial surface communities by 454 pyrosequencing demonstrated that the antifouling activity of nonpolar algal surface compounds was targeting the abundance of natural bacterial colonizers rather than the relative composition of bacterial members within the community. Moreover, the bacterial community composition on F. vesiculosus was markedly different from artificial control substrates and chemically manipulated experimental treatments, suggesting that other, nonextractable surface features and/or physical properties render algal-specific epiphytic bacterial communities.

  16. High Frequency Monitoring for Harmful Algal Blooms

    EPA Science Inventory

    Harmful algal blooms (HABs) are increasingly becoming a significant ecologic, economic, and social driver in the use of water resources. Cyanobacteria and their toxins play an important role in management decisions for drinking water utilities and public health officials. Online ...

  17. Factsheet: Climate Change and Harmful Algal Blooms

    EPA Pesticide Factsheets

    Climate change is predicted to change many environmental conditions that could affect the properties of fresh and marine waters. These changes could favor the growth of harmful algal blooms and habitat changes.

  18. Eukaryotic algal phytochromes span the visible spectrum

    PubMed Central

    Rockwell, Nathan C.; Duanmu, Deqiang; Martin, Shelley S.; Bachy, Charles; Price, Dana C.; Bhattacharya, Debashish; Worden, Alexandra Z.; Lagarias, J. Clark

    2014-01-01

    Plant phytochromes are photoswitchable red/far-red photoreceptors that allow competition with neighboring plants for photosynthetically active red light. In aquatic environments, red and far-red light are rapidly attenuated with depth; therefore, photosynthetic species must use shorter wavelengths of light. Nevertheless, phytochrome-related proteins are found in recently sequenced genomes of many eukaryotic algae from aquatic environments. We examined the photosensory properties of seven phytochromes from diverse algae: four prasinophyte (green algal) species, the heterokont (brown algal) Ectocarpus siliculosus, and two glaucophyte species. We demonstrate that algal phytochromes are not limited to red and far-red responses. Instead, different algal phytochromes can sense orange, green, and even blue light. Characterization of these previously undescribed photosensors using CD spectroscopy supports a structurally heterogeneous chromophore in the far-red–absorbing photostate. Our study thus demonstrates that extensive spectral tuning of phytochromes has evolved in phylogenetically distinct lineages of aquatic photosynthetic eukaryotes. PMID:24567382

  19. Environmental performance of algal biofuel technology options.

    PubMed

    Vasudevan, Venkatesh; Stratton, Russell W; Pearlson, Matthew N; Jersey, Gilbert R; Beyene, Abraham G; Weissman, Joseph C; Rubino, Michele; Hileman, James I

    2012-02-21

    Considerable research and development is underway to produce fuels from microalgae, one of several options being explored for increasing transportation fuel supplies and mitigating greenhouse gas emissions (GHG). This work models life-cycle GHG and on-site freshwater consumption for algal biofuels over a wide technology space, spanning both near- and long-term options. The environmental performance of algal biofuel production can vary considerably and is influenced by engineering, biological, siting, and land-use considerations. We have examined these considerations for open pond systems, to identify variables that have a strong influence on GHG and freshwater consumption. We conclude that algal biofuels can yield GHG reductions relative to fossil and other biobased fuels with the use of appropriate technology options. Further, freshwater consumption for algal biofuels produced using saline pond systems can be comparable to that of petroleum-derived fuels.

  20. Climate Adaptation and Harmful Algal Blooms

    EPA Pesticide Factsheets

    EPA supports local, state and tribal efforts to maintain water quality. A key element of its efforts is to reduce excess nutrient pollution and the resulting adverse impacts, including harmful algal blooms.

  1. p16INK4A inactivation mechanisms in non-small-cell lung cancer patients occupationally exposed to asbestos.

    PubMed

    Andujar, Pascal; Wang, Jinhui; Descatha, Alexis; Galateau-Sallé, Françoise; Abd-Alsamad, Issam; Billon-Galland, Marie-Annick; Blons, Hélène; Clin, Bénédicte; Danel, Claire; Housset, Bruno; Laurent-Puig, Pierre; Le Pimpec-Barthes, Françoise; Letourneux, Marc; Monnet, Isabelle; Régnard, Jean-François; Renier, Annie; Zucman-Rossi, Jessica; Pairon, Jean-Claude; Jaurand, Marie-Claude

    2010-01-01

    Epidemiological studies have shown that asbestos fibers constitute the major occupational risk factor and that asbestos acts synergistically with tobacco smoking to induce lung cancer. Although some somatic gene alterations in lung cancer have been linked to tobacco smoke, few data are available on the role of asbestos fibers. P16/CDKN2A is an important tumor suppressor gene that is frequently altered in lung cancer via promoter 5'-CpG island hypermethylation and homozygous deletion, and rarely via point mutation. Many studies suggest that tobacco smoking produces P16/CDKN2A promoter hypermethylation in lung cancer, but the status of this gene in relation to asbestos exposure has yet to be determined. The purpose of this study was to investigate the mechanism of P16/CDKN2A alterations in lung cancer in asbestos-exposed patients. P16/CDKN2A gene status was studied in 75 human non-small-cell lung cancer (NSCLC) cases with well-defined smoking habits, and detailed assessment of asbestos exposure, based on occupational questionnaire and determination of asbestos bodies in lung tissue. The results of this study confirm published data on the effect of tobacco smoke on P16/CDKN2A gene alterations, characterized by significantly higher P16/CDKN2A promoter hypermethylation in heavy smokers (more than 40 pack-years (P-Y)) than in smokers of less than 40 P-Y. These results also demonstrate a higher incidence of loss of heterozygosity and homozygous deletion in asbestos-exposed cases, after adjustment for age and cumulative tobacco consumption, than in unexposed cases (P=0.0062). This study suggests that P16/CDKN2A gene inactivation in asbestos-exposed NSCLC cases mainly occurs via deletion, a feature also found in malignant mesothelioma, a tumor independent of tobacco smoking but associated with asbestos exposure, suggesting a possible relationship with an effect of asbestos fibers.

  2. Reversible alterations in epithelial cell turnover in digestive gland of winkles (Littorina littorea) exposed to cadmium and their implications for biomarker measurements.

    PubMed

    Zaldibar, B; Cancio, I; Marigómez, I

    2007-02-28

    In marine molluscs, the epithelium of the digestive gland is composed of two cell types, namely, digestive and basophilic cells. Under normal physiological conditions digestive cells outnumber basophilic cells, but under different stress situations the composition of the epithelium changes, basophilic cells apparently replace digestive cell. Winkles, Littorina littorea, were exposed to 1.25mg/l Cd for 20 days to provoke cell type replacement. Then, animals were depurated in clean seawater for 10 days to determine whether cell type replacement was reversible. Digestive glands were fixed in Carnoy and paraffin embedded for histological analysis. The volume densities of basophilic cells (Vv(BAS)) and digestive cells (Vv(DIG)) were calculated by stereology on hematoxylin-eosin stained sections. Vv(BAS) increased and Vv(DIG) decreased in Cd-exposed animals. After estimation of cell size and absolute cell numbers, these changes were attributed to digestive cell loss and concomitant basophilic cell hypertrophy but not to increased numbers of basophilic cells. Cell type composition and cell size almost fully returned to normal values after 10-day depuration. Accordingly, PCNA immunohistochemistry demonstrated that proliferating digestive cells were more abundant in winkles exposed to Cd and after 10-day depuration than in control specimens, suggesting that net digestive cell loss was accompanied by increased digestive cell proliferation. Thus, Cd-exposure seems to provoke an enhanced digestive cell turnover in order to cope with Cd detoxification. Intralysosomal accumulation of metals (autometallographied black silver deposits; BSD) was used as a biomarker of exposure to Cd and lysosomal structural changes as an effect biomarker to see whether cell type composition might have any effect on these endpoints. BSD formed around Cd ions, in digestive cell lysosomes of Cd-exposed winkles whereas basophilic cells appeared devoid of them. After depuration, BSD were less

  3. Anatase TiO(2) nanosheets with exposed (001) facets: improved photoelectric conversion efficiency in dye-sensitized solar cells.

    PubMed

    Yu, Jiaguo; Fan, Jiajie; Lv, Kangle

    2010-10-01

    Dye-sensitized solar cells (DSSCs) are fabricated based on anatase TiO(2) nanosheets (TiO(2)-NSs) with exposed {001} facets, which were obtained by a simple one-pot hydrothermal route using HF as a morphology controlling agent and Ti(OC(4)H(9))(4) as precursor. The prepared samples were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, UV-vis absorption spectroscopy and N(2) adsorption-desorption isotherms. The photoelectric conversion performances of TiO(2)-NSs solar cells are also compared with TiO(2) nanoparticles (TiO(2)-NPs) and commercial-grade Degussa P25 TiO(2) nanoparticle (P25) solar cells at the same film thickness, and their photoelectric conversion efficiencies (η) are 4.56, 4.24 and 3.64%, respectively. The enhanced performance of the TiO(2)-NS solar cell is due to their good crystallization, high pore volume, large particle size and enhanced light scattering. The prepared TiO(2) nanosheet film electrode should also find wide-ranging potential applications in various fields including photocatalysis, catalysis, electrochemistry, separation, purification and so on.

  4. Enhancement of water retention in UV-exposed fuel-cell proton exchange membranes studied using terahertz spectroscopy

    NASA Astrophysics Data System (ADS)

    Ray, Shaumik; Devi, Nirmala; Dash, Jyotirmayee; Rambabu, Gutru; Bhat, Santoshkumar D.; Pesala, Bala

    2016-02-01

    Proton Exchange Membrane (PEM) fuel cells are increasingly gaining importance as a clean energy source. PEMs need to possess high proton conductivity and should be chemically and mechanically stable in the fuel cell environment. Proton conductivity of PEM in fuel cells is directly proportional to water content in the membrane. Among the various PEMs available, Nafion has high proton conductivity even with low water content compared to SPEEK (Sulfonated Poly(ether ether ketone)) but is also expensive. SPEEK membranes and it's composites have better mechanical properties and have comparatively higher thermal stability. Operating the fuel cell at higher temperatures and at the same time maintaining the water content of the membrane is always a great challenge. In this paper, to increase water retention capacity, Nafion, SPEEK and it's composite (SPEEK PSSA-CNT) membranes are exposed to Ultra-Violet (UV) radiation for varied times. Terahertz Spectroscopy, in both pulsed and CW mode has been used as an efficient tool to quantify the water retention of the membrane. Results using Terahertz spectroscopy show that even though the initial water absorption capacity of Nafion membranes is more, SPEEK membranes and it's composites show considerable improvement in the water retention capacity upon high intensity UV irradiation.

  5. Phosphorylation of p53 at serine 15 in A549 pulmonary epithelial cells exposed to vanadate: Involvement of ATM pathway

    SciTech Connect

    Suzuki, Katsura; Inageda, Kiyoshi; Nishitai, Gen; Matsuoka, Masato . E-mail: matsuoka@research.twmu.ac.jp

    2007-04-01

    When A549 cells were exposed to sodium metavanadate (NaVO{sub 3}), the pentavalent species of vanadium (vanadate), phosphorylation of p53 protein at Ser15 was found in a time (8-48 h)- and dose (10-200 {mu}M)-dependent manner. After the incubation with 50 or 100 {mu}M NaVO{sub 3} for 48 h, accumulation of p53 protein was accompanied with Ser15 phosphorylation. Among serines in p53 protein immunoprecipitated from A549 cells treated with 100 {mu}M NaVO{sub 3} for 48 h, only Ser15 was markedly phosphorylated. Treatment with other vanadate compounds, sodium orthovanadate (Na{sub 3}VO{sub 4}) and ammonium metavanadate (NH{sub 4}VO{sub 3}), also induced Ser15 phosphorylation and accumulation of p53 protein. While phosphorylation of extracellular signal-regulated protein kinase (ERK) was found in cells treated with NaVO{sub 3}, treatment with U0126 did not suppress Ser15 phosphorylation. On the other hand, treatment with wortmannin or caffeine, the inhibitors to phosphatidylinositol 3-kinase related kinases (PIKKs), suppressed both NaVO{sub 3}-induced Ser15 phosphorylation and accumulation of p53 protein. The silencing of ataxia telangiectasia mutated (ATM) expression using short-interference RNA resulted in the marked suppression of Ser15 phosphorylation in A549 cells exposed to NaVO{sub 3}. However, treatment with antioxidants such as catalase and N-acetylcysteine did not suppress NaVO{sub 3}-induced Ser15 phosphorylation. Transcriptional activation of p53 and DNA fragmentation in A549 cells treated with NaVO{sub 3} were suppressed only slightly by S15A mutation, suggesting that Ser15 phosphorylation is not essential for these responses. The present results showed that vanadate induces the phosphorylation of p53 at Ser15 depending on ATM, one of the members of PIKK family, in this human pulmonary epithelial cell line.

  6. Gamma-H2AX foci in cells exposed to a mixed beam of X-rays and alpha particles

    PubMed Central

    2012-01-01

    Background Little is known about the cellular effects of exposure to mixed beams of high and low linear energy transfer radiation. So far, the effects of combined exposures have mainly been assessed with clonogenic survival or cytogenetic methods, and the results are contradictory. The gamma-H2AX assay has up to now not been applied in this context, and it is a promising tool for investigating the early cellular response to mixed beam irradiation. Purpose To determine the dose response and repair kinetics of gamma-H2AX ionizing radiation-induced foci in VH10 human fibroblasts exposed to mixed beams of 241Am alpha particles and X-rays. Results VH10 human fibroblasts were irradiated with each radiation type individually or both in combination at 37°C. Foci were scored for repair kinetics 0.5, 1, 3 and 24 h after irradiation (one dose per irradiation type), and for dose response at the 1 h time point. The dose response effect of mixed beam was additive, and the relative biological effectiveness for alpha particles (as compared to X-rays) was of 0.76 ± 0.52 for the total number of foci, and 2.54 ± 1.11 for large foci. The repair kinetics for total number of foci in cells exposed to mixed beam irradiation was intermediate to that of cells exposed to alpha particles and X-rays. However, for mixed beam-irradiated cells the frequency and area of large foci were initially lower than predicted and increased during the first 3 hours of repair (while the predicted number and area did not). Conclusions The repair kinetics of large foci after mixed beam exposure was significantly different from predicted based on the effect of the single dose components. The formation of large foci was delayed and they did not reach their maximum area until 1 h after irradiation. We hypothesize that the presence of low X-ray-induced damage engages the DNA repair machinery leading to a delayed DNA damage response to the more complex DNA damage induced by alpha particles. PMID:23121736

  7. Direct conversion of algal biomass to biofuel

    DOEpatents

    Deng, Shuguang; Patil, Prafulla D; Gude, Veera Gnaneswar

    2014-10-14

    A method and system for providing direct conversion of algal biomass. Optionally, the method and system can be used to directly convert dry algal biomass to biodiesels under microwave irradiation by combining the reaction and combining steps. Alternatively, wet algae can be directly processed and converted to fatty acid methyl esters, which have the major components of biodiesels, by reacting with methanol at predetermined pressure and temperature ranges.

  8. Induction of Cell Death Through Alteration of Oxidants and Antioxidants in Epithelial Cells Exposed to High Energy Protons

    NASA Astrophysics Data System (ADS)

    Ramesh, Govindarajan; Wu, Honglu

    2012-07-01

    Radiation affects several cellular and molecular processes including double strand breakage, modifications of sugar moieties and bases. In outer space, protons are the primary radiation source which poses a range of potential health risks to astronauts. On the other hand, the use of proton radiation for tumor radiation therapy is increasing as it largely spares healthy tissues while killing tumor tissues. Although radiation related research has been conducted extensively, the molecular toxicology and cellular mechanisms affected by proton radiation remain poorly understood. Therefore, in the present study, we irradiated rat epithelial cells (LE) with different doses of protons and investigated their effects on cell proliferation and cell death. Our data showed an inhibition of cell proliferation in proton irradiated cells with a significant dose dependent activation and repression of reactive oxygen species (ROS) and antioxidants, glutathione and superoxide dismutase respectively as compared to control cells. In addition, apoptotic related genes such as caspase-3 and -8 activities were induced in a dose dependent manner with corresponding increased levels of DNA fragmentation in proton irradiated cells than control cells. Together, our results show that proton radiation alters oxidant and antioxidant levels in the cells to activate apoptotic pathway for cell death.

  9. Induction of Cell Death through Alteration of Oxidants and Antioxidants in Epithelial Cells Exposed to High Energy Protons

    NASA Technical Reports Server (NTRS)

    Ramesh, Govindarajan; Wu, Honglu

    2012-01-01

    Radiation affects several cellular and molecular processes including double strand breakage, modifications of sugar moieties and bases. In outer space, protons are the primary radiation source which poses a range of potential health risks to astronauts. On the other hand, the use of proton radiation for tumor radiation therapy is increasing as it largely spares healthy tissues while killing tumor tissues. Although radiation related research has been conducted extensively, the molecular toxicology and cellular mechanisms affected by proton radiation remain poorly understood. Therefore, in the present study, we irradiated rat epithelial cells (LE) with different doses of protons and investigated their effects on cell proliferation and cell death. Our data showed an inhibition of cell proliferation in proton irradiated cells with a significant dose dependent activation and repression of reactive oxygen species (ROS) and antioxidants, glutathione and superoxide dismutase respectively as compared to control cells. In addition, apoptotic related genes such as caspase-3 and -8 activities were induced in a dose dependent manner with corresponding increased levels of DNA fragmentation in proton irradiated cells than control cells. Together, our results show that proton radiation alters oxidant and antioxidant levels in the cells to activate apoptotic pathway for cell death.

  10. DNA methylation analysis in rat kidney epithelial cells exposed to 3-MCPD and glycidol.

    PubMed

    Senyildiz, Mine; Alpertunga, Buket; Ozden, Sibel

    2016-11-24

    3-Monochloropropane-1,2-diol (3-MCPD) is a well-known food processing contaminant that has been regarded as a rat carcinogen, which is known to induce Leydig-cell and mammary gland tumors in males, as well as kidney tumors in both genders. 3-MCPD is highly suspected to be a non-genotoxic carcinogen. 2,3-Epoxy-1-propanol (glycidol) can be formed via dehalogenation from 3-MCPD. We aimed to investigate the cytotoxic effects of 3-MCPD and glycidol, then to demonstrate the possible epigenetic mechanisms with global and gene-specific DNA methylation in rat kidney epithelial cells (NRK-52E). IC50 value of 3-MCPD was determined as 48 mM and 41.39 mM, whereas IC50 value of glycidol was 1.67 mM and 1.13 mM by MTT and NRU test, respectively. Decreased global DNA methylation at the concentrations of 100 μM and 1000 μM for 3-MCPD and 100 μM and 500 μM for glycidol were observed after 48 h exposure by using 5-methylcytosine (5-mC) ELISA kit. Methylation changes were detected in promoter regions of c-myc and Rassf1a in 3-MCPD and glycidol treated NRK-52E cells by using methylation-specific PCR (MSP), whereas changes on gene expression of c-myc and Rassf1a were observed by using real-time PCR. However, e-cadherin, p16, VHL and p15 genes were unmethylated in their CpG promoter regions in response to treatment with 3-MCPD and glycidol. Alterations in DNA methylation might be key events in the toxicity of 3-MCPD and glycidol.

  11. Knockdown of AKR1C3 exposes a potential epigenetic susceptibility in prostate cancer cells

    PubMed Central

    Doig, Craig L.; Battaglia, Sebastiano; Khanim, Farhat L.; Bunce, Christopher M.; Campbell, Moray J.

    2017-01-01

    Background The aldo-keto reductase 1C3 (AKR1C3) has been heavily implicated in the propagation of prostate malignancy. AKR1C3 protein is elevated within prostate cancer tissue, it contributes to the formation of androgens and downstream stimulation of the androgen receptor (AR). Elevated expression of AKR1C3 is also reported in acute myeloid leukemia but the target nuclear receptors have been identified as members of the peroxisome-proliferator activated receptor (PPARs) subfamily. Thus, AKR1C3 cancer biology is likely to be tissue dependent and hormonally linked to the availability of ligands for both the steroidogenic and non-steroidogenic nuclear receptors. Methods In the current study we investigated the potential for AKR1C3 to regulate the availability of prostaglandin-derived ligands for PPARg mainly, prostaglandin J2 (PGJ2). Using prostate cancer cell lines with stably reduced AKR1C3 levels we examined the impact of AKR1C3 upon proliferation mediated by PPAR ligands. Results These studies revealed knockdown of AKR1C3 had no effect upon the sensitivity of androgen receptor independent prostate cancer cells towards PPAR ligands. However, the reduction of levels of AKR1C3 was accompanied by a significantly reduced mRNA expression of a range of HDACs, transcriptional co-regulators, and increased sensitivity towards SAHA, a clinically approved histone deacetylase inhibitor. Conclusions These results suggest a hitherto unidentified link between AKR1C3 levels and the epigenetic status in prostate cancer cells. This raises an interesting possibility of a novel rational to target AKR1C3, the utilization of AKRIC3 selective inhibitors in combination with HDAC inhibition as part of novel epigenetic therapies in androgen deprivation therapy recurrent prostate cancer. PMID:26429394

  12. Reactive oxygen species regulated mitochondria-mediated apoptosis in PC12 cells exposed to chlorpyrifos

    SciTech Connect

    Lee, Jeong Eun; Park, Jae Hyeon; Shin, In Chul; Koh, Hyun Chul

    2012-09-01

    Reactive oxidative species (ROS) generated by environmental toxicants including pesticides could be one of the factors underlying the neuronal cell damage in neurodegenerative diseases. In this study we found that chlorpyrifos (CPF) induced apoptosis in dopaminergic neuronal components of PC12 cells as demonstrated by the activation of caspases and nuclear condensation. Furthermore, CPF also reduced the tyrosine hydroxylase-positive immunoreactivity in substantia nigra of the rat. In addition, CPF induced inhibition of mitochondrial complex I activity. Importantly, N-acetyl cysteine (NAC) treatment effectively blocked apoptosis via the caspase-9 and caspase-3 pathways while NAC attenuated the inhibition of mitochondrial complex I activity as well as the oxidative metabolism of dopamine (DA). These results demonstrated that CPF-induced apoptosis was involved in mitochondrial dysfunction through the production of ROS. In the response of cellular antioxidant systems to CPF, we found that CPF treatment increased HO-1 expression while the expression of CuZnSOD and MnSOD was reduced. In addition, we found that CPF treatment activated MAPK pathways, including ERK 1/2, the JNK, and the p38 MAP kinase in a time-dependent manner. NAC treatment abolished MAPK phosphorylation caused by CPF, indicating that ROS are upstream signals of MAPK. Interestingly, MAPK inhibitors abolished cytotoxicity and reduced ROS generation by CPF treatment. Our results demonstrate that CPF induced neuronal cell death in part through MAPK activation via ROS generation, suggesting its potential to generate oxidative stress via mitochondrial damage and its involvement in oxidative stress-related neurodegenerative disease. -- Highlights: ► Chlorpyrifos induces apoptosis. ► Chlorpyrifos inhibits mitochondrial complex I activity. ► ROS is involved in chlorpyrifos-induced apoptosis. ► Chlorpyrifos affects cellular antioxidant systems. ► Chlorpyrifos-induced apoptosis mediates activation of MAPK.

  13. Modulation of mitochondrial gene expression in pulmonary epithelial cells exposed to oxidants.

    PubMed Central

    Janssen, Y M; Driscoll, K E; Timblin, C R; Hassenbein, D; Mossman, B T

    1998-01-01

    Oxidants are important in the regulation of signal transduction and gene expression. Multiple classes of genes are transcriptionally activated by oxidants and are implicated in different phenotypic responses. In the present study, we performed differential mRNA display to elucidate genes that are induced or repressed after exposure of rat lung epithelial (RLE) cells to H2O2 or crocidolite asbestos, a pathogenic mineral that generates oxidants. After 8 or 24 hr of exposure, RNA was extracted, reverse transcribed, and amplified by polymerase chain reaction with degenerate primers to visualize alterations in gene expression. The seven clones obtained were sequenced and encoded the mitochondrial genes, NADH dehydrogenase subunits ND5 and ND6, and 16S ribosomal RNA. Evaluation of their expression by Northern blot analysis revealed increased expression of 16S rRNA after 1 or 2 hr of exposure to H2O2. At later time periods (4 and 24 hr), mRNA levels of 16S rRNA and NADH dehydrogenase were decreased in H2O2-treated RLE cells when compared to sham controls. Crocidolite asbestos caused increases in 16S rRNA levels after 8 hr of exposure, whereas after 24 hr of exposure to asbestos, 16S rRNA levels were decreased in comparison to sham controls. In addition to these oxidants, the nitric oxide generator spermine NONOate caused similar decreases in NADH dehydrogenase mRNA levels after 4 hr of exposure. The present data and previous studies demonstrated that all oxidants examined resulted in apoptosis in RLE cells during the time frame where alterations of mitochondrial gene expression were observed. As the mitochondrion is a major organelle that controls apoptosis, alterations in expression of mitochondrial genes may be involved in the regulation of apoptosis. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:9788897

  14. Lineage-related cytotoxicity and clonogenic profile of 1,4-benzoquinone-exposed hematopoietic stem and progenitor cells

    SciTech Connect

    Chow, Paik Wah; Abdul Hamid, Zariyantey; Chan, Kok Meng; Inayat-Hussain, Salmaan Hussain; Rajab, Nor Fadilah

    2015-04-01

    Hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs) are sensitive targets for benzene-induced hematotoxicity and leukemogenesis. The impact of benzene exposure on the complex microenvironment of HSCs and HPCs remains elusive. This study aims to investigate the mechanism linking benzene exposure to targeting HSCs and HPCs using phenotypic and clonogenic analyses. Mouse bone marrow (BM) cells were exposed ex vivo to the benzene metabolite, 1,4-benzoquinone (1,4-BQ), for 24 h. Expression of cellular surface antigens for HSC (Sca-1), myeloid (Gr-1, CD11b), and lymphoid (CD45, CD3e) populations were confirmed by flow cytometry. The clonogenicity of cells was studied using the colony-forming unit (CFU) assay for multilineage (CFU-GM and CFU-GEMM) and single-lineage (CFU-E, BFU-E, CFU-G, and CFU-M) progenitors. 1,4-BQ demonstrated concentration-dependent cytotoxicity in mouse BM cells. The percentage of apoptotic cells increased (p < 0.05) following 1,4-BQ exposure. Exposure to 1,4-BQ showed no significant effect on CD3e{sup +} cells but reduced the total counts of Sca-1{sup +}, CD11b{sup +}, Gr-1{sup +}, and CD45{sup +} cells at 7 and 12 μM (p < 0.05). Furthermore, the CFU assay showed reduced (p < 0.05) clonogenicity in 1,4-BQ-treated cells. 1,4-BQ induced CFU-dependent cytotoxicity by significantly inhibiting colony growth for CFU-E, BFU-E, CFU-G, and CFU-M starting at a low concentration of exposure (5 μM); whereas for the CFU-GM and CFU-GEMM, the inhibition of colony growth was remarkable only at 7 and 12 μM of 1,4-BQ, respectively. Taken together, 1,4-BQ caused lineage-related cytotoxicity in mouse HPCs, demonstrating greater toxicity in single-lineage progenitors than in those of multi-lineage. - Highlights: • We examine 1,4-BQ toxicity targeting mouse hematopoietic cell lineages. • 1,4-BQ induces concentration-dependent cytotoxicity in bone marrow (BM) cells. • 1,4-BQ shows lineage-related toxicity on hematopoietic stem and

  15. Transcriptomic changes in mouse embryonic stem cells exposed to thalidomide during spontaneous differentiation

    PubMed Central

    Gao, Xiugong; Sprando, Robert L.; Yourick, Jeffrey J.

    2015-01-01

    Thalidomide is a potent developmental toxicant that induces a range of birth defects, notably severe limb malformations. To unravel the molecular mechanisms underpinning the teratogenic effects of thalidomide, we used microarrays to study transcriptomic changes induced by thalidomide in an in vitro model based on the differentiation of mouse embryonic stem cells (mESCs), and published the major findings in a research article entitled “Thalidomide induced early gene expression perturbations indicative of human embryopathy in mouse embryonic stem cells” [1]. The data presented herein contains complementary information related to the aforementioned research article. PMID:26217789

  16. Evaluation of respiration of mitochondria in cancer cells exposed to mitochondria-targeted agents.

    PubMed

    Kluckova, Katarina; Dong, Lan-Feng; Bajzikova, Martina; Rohlena, Jakub; Neuzil, Jiri

    2015-01-01

    Respiration is one of the major functions of mitochondria, whereby these vital organelles use oxygen to produce energy. Many agents that may be of potential clinical relevance act by targeting mitochondria, where they may suppress mitochondrial respiration. It is therefore important to evaluate this process and understand how this is modulated by small molecules. Here, we describe the general methodology to assess respiration in cultured cells, followed by the evaluation of the effect of one anticancer agent targeted to mitochondria on this process, and also how to assess this in tumor tissue.

  17. Using the DNA alkaline unwinding assay to detect DNA damage in laboratory and environmentally exposed cells and tissues

    SciTech Connect

    Nacci, D.; Jackim, E.

    1990-01-01

    The DNA alkaline unwinding assay is being evaluated for use in the detection of DNA damage in marine animals exposed to environmental pollutants. In preliminary work, DNA unwinding methods were used with in vitro cell systems to demonstrate DNA strand breaks. Cultured mammalian fibroblasts and sperm from marine fish and invertebrates (Pseudopleuronectes, Arbacia and Mytilus) showed concentration-dependent increases in DNA strand breaks after brief exposures to alkylating agents. DNA unwinding methods were also used on DNA extracted from marine animals injected with genotoxicants and from animals exposed in situ at an estuarine site. Gills from blue mussels caged at the New Bedford Harbor Superfund Site (MA, USA) highly contaminated with many organic (e.g. PCBs) and inorganic contaminants, were also examined. A significant increase in DNA strand breaks was seen in gill tissues of animals held in the contaminated site for as little as 3 days. Although not as severe, an increase in strand breaks was also seen in animals held at the control site for 28 days.

  18. Comparing new and conventional methods to estimate benthic algal biomass and composition in freshwaters.

    PubMed

    Kahlert, Maria; McKie, Brendan G

    2014-11-01

    We compared conventional microscope-based methods for quantifying biomass and community composition of stream benthic algae with output obtained for these parameters from a new instrument (the BenthoTorch), which measures fluorescence of algal pigments in situ. Benthic algae were studied in 24 subarctic oligotrophic (1.7-26.9, median 7.2 μg total phosphorus L(-1)) streams in Northern Sweden. Readings for biomass of the total algal mat, quantified as chlorophyll a, did not differ significantly between the BenthoTorch (median 0.52 μg chlorophyll a cm(-2)) and the conventional method (median 0.53 μg chlorophyll a cm(-2)). However, quantification of community composition of the benthic algal mat obtained using the BenthoTorch did not match those obtained from conventional methods. The BenthoTorch indicated a dominance of diatoms, whereas microscope observations showed a fairly even distribution between diatoms, blue-green algae (mostly nitrogen-fixing) and green algae (mostly large filamentous), and also detected substantial biovolumes of red algae in some streams. These results most likely reflect differences in the exact parameters quantified by the two methods, as the BenthoTorch does not account for variability in cell size and the presence of non-chlorophyll bearing biomass in estimating the proportion of different algal groups, and does not distinguish red algal chlorophyll from that of other algal groups. Our findings suggest that the BenthoTorch has utility in quantifying biomass expressed as μg chlorophyll a cm(-2), but its output for the relative contribution of different algal groups to benthic algal biomass should be used with caution.

  19. Direct utilization of waste water algal biomass for ethanol production by cellulolytic Clostridium phytofermentans DSM1183.

    PubMed

    Fathima, Anwar Aliya; Sanitha, Mary; Kumar, Thangarathinam; Iyappan, Sellamuthu; Ramya, Mohandass

    2016-02-01

    Direct bioconversion of waste water algal biomass into ethanol using Clostridium phytofermentans DSM1183 was demonstrated in this study. Fermentation of 2% (w/v) autoclaved algal biomass produced ethanol concentration of 0.52 g L(-1) (solvent yield of 0.19 g/g) where as fermentation of acid pretreated algal biomass (2%, w/v) produced ethanol concentration of 4.6 g L(-1) in GS2 media (solvent yield of 0.26 g/g). The control experiment with 2% (w/v) glucose in GS2 media produced ethanol concentration of 2.8 g L(-1) (solvent yield of 0.25 g/g). The microalgal strains from waste water algal biomass were identified as Chlamydomonas dorsoventralis, Graesiella emersonii, Coelastrum proboscideum, Scenedesmus obliquus, Micractinium sp., Desmodesmus sp., and Chlorella sp., based on ITS-2 molecular marker. The presence of glucose, galactose, xylose and rhamnose were detected by high performance liquid chromatography in the algal biomass. Scanning Electron Microscopy observations of fermentation samples showed characteristic morphological changes in algal cells and bioaccessibility of C. phytofermentans.

  20. Investigating why recycling gravity harvested algae increases harvestability and productivity in high rate algal ponds.

    PubMed

    Park, J B K; Craggs, R J; Shilton, A N

    2013-09-15

    It has previously been shown that recycling gravity harvested algae promotes Pediastrum boryanum dominance and improves harvestability and biomass production in pilot-scale High Rate Algal Ponds (HRAPs) treating domestic wastewater. In order to confirm the reproducibility of these findings and investigate the mechanisms responsible, this study utilized twelve 20 L outdoor HRAP mesocosms operated with and without algal recycling. It then compared the recycling of separated solid and liquid components of the harvested biomass against un-separated biomass. The work confirmed that algal recycling promoted P. boryanum dominance, improved 1 h-settleability by >20% and increased biomass productivity by >25% compared with controls that had no recycling. With regard to the improved harvestability, of particular interest was that recycling the liquid fraction alone caused a similar improvement in settleability as recycling the solid fraction. This may be due to the presence of extracellular polymeric substances in the liquid fraction. While there are many possible mechanisms that could account for the increased productivity with algal recycling, all but two were systematically eliminated: (i) the mean cell residence time was extended thereby increasing the algal concentration and more fully utilizing the incident sunlight and, (ii) the relative proportions of algal growth stages (which have different specific growth rates) was changed, resulting in a net increase in the overall growth rate of the culture.

  1. Characteristics of Myeloid Differentiation and Maturation Pathway Derived from Human Hematopoietic Stem Cells Exposed to Different Linear Energy Transfer Radiation Types

    PubMed Central

    Monzen, Satoru; Yoshino, Hironori; Kasai-Eguchi, Kiyomi; Kashiwakura, Ikuo

    2013-01-01

    Exposure of hematopoietic stem/progenitor cells (HSPCs) to ionizing radiation causes a marked suppression of mature functional blood cell production in a linear energy transfer (LET)- and/or dose-dependent manner. However, little information about LET effects on the proliferation and differentiation of HSPCs has been reported. With the aim of characterizing the effects of different types of LET radiations on human myeloid hematopoiesis, in vitro hematopoiesis in Human CD34+ cells exposed to carbon-ion beams or X-rays was compared. Highly purified CD34+ cells exposed to each form of radiation were plated onto semi-solid culture for a myeloid progenitor assay. The surviving fractions of total myeloid progenitors, colony-forming cells (CFC), exposed to carbon-ion beams were significantly lower than of those exposed to X-rays, indicating that CFCs are more sensitive to carbon-ion beams (D0 = 0.65) than to X-rays (D0 = 1.07). Similar sensitivities were observed in granulocyte-macrophage and erythroid progenitors, respectively. However, the sensitivities of mixed-type progenitors to both radiation types were similar. In liquid culture for 14 days, no significant difference in total numbers of mononuclear cells was observed between non-irradiated control culture and cells exposed to 0.5 Gy X-rays, whereas 0.5 Gy carbon-ion beams suppressed cell proliferation to 4.9% of the control, a level similar to that for cells exposed to 1.5 Gy X-rays. Cell surface antigens associated with terminal maturation, such as CD13, CD14, and CD15, on harvest from the culture of X-ray-exposed cells were almost the same as those from the non-irradiated control culture. X-rays increased the CD235a+ erythroid-related fraction, whereas carbon-ion beams increased the CD34+CD38− primitive cell fraction and the CD13+CD14+/−CD15− fraction. These results suggest that carbon-ion beams inflict severe damage on the clonal growth of myeloid HSPCs, although the intensity of cell surface

  2. Characteristics of myeloid differentiation and maturation pathway derived from human hematopoietic stem cells exposed to different linear energy transfer radiation types.

    PubMed

    Monzen, Satoru; Yoshino, Hironori; Kasai-Eguchi, Kiyomi; Kashiwakura, Ikuo

    2013-01-01

    Exposure of hematopoietic stem/progenitor cells (HSPCs) to ionizing radiation causes a marked suppression of mature functional blood cell production in a linear energy transfer (LET)- and/or dose-dependent manner. However, little information about LET effects on the proliferation and differentiation of HSPCs has been reported. With the aim of characterizing the effects of different types of LET radiations on human myeloid hematopoiesis, in vitro hematopoiesis in Human CD34(+) cells exposed to carbon-ion beams or X-rays was compared. Highly purified CD34(+) cells exposed to each form of radiation were plated onto semi-solid culture for a myeloid progenitor assay. The surviving fractions of total myeloid progenitors, colony-forming cells (CFC), exposed to carbon-ion beams were significantly lower than of those exposed to X-rays, indicating that CFCs are more sensitive to carbon-ion beams (D(0) = 0.65) than to X-rays (D(0) = 1.07). Similar sensitivities were observed in granulocyte-macrophage and erythroid progenitors, respectively. However, the sensitivities of mixed-type progenitors to both radiation types were similar. In liquid culture for 14 days, no significant difference in total numbers of mononuclear cells was observed between non-irradiated control culture and cells exposed to 0.5 Gy X-rays, whereas 0.5 Gy carbon-ion beams suppressed cell proliferation to 4.9% of the control, a level similar to that for cells exposed to 1.5 Gy X-rays. Cell surface antigens associated with terminal maturation, such as CD13, CD14, and CD15, on harvest from the culture of X-ray-exposed cells were almost the same as those from the non-irradiated control culture. X-rays increased the CD235a(+) erythroid-related fraction, whereas carbon-ion beams increased the CD34(+)CD38(-) primitive cell fraction and the CD13(+)CD14(+/-)CD15(-) fraction. These results suggest that carbon-ion beams inflict severe damage on the clonal growth of myeloid HSPCs, although the intensity of cell surface

  3. Algal and fungal diversity in Antarctic lichens.

    PubMed

    Park, Chae Haeng; Kim, Kyung Mo; Elvebakk, Arve; Kim, Ok-Sun; Jeong, Gajin; Hong, Soon Gyu

    2015-01-01

    The composition of lichen ecosystems except mycobiont and photobiont has not been evaluated intensively. In addition, recent studies to identify algal genotypes have raised questions about the specific relationship between mycobiont and photobiont. In the current study, we analyzed algal and fungal community structures in lichen species from King George Island, Antarctica, by pyrosequencing of eukaryotic large subunit (LSU) and algal internal transcribed spacer (ITS) domains of the nuclear rRNA gene. The sequencing results of LSU and ITS regions indicated that each lichen thallus contained diverse algal species. The major algal operational taxonomic unit (OTU) defined at a 99% similarity cutoff of LSU sequences accounted for 78.7-100% of the total algal community in each sample. In several cases, the major OTUs defined by LSU sequences were represented by two closely related OTUs defined by 98% sequence similarity of ITS domain. The results of LSU sequences indicated that lichen-associated fungi belonged to the Arthoniomycetes, Eurotiomycetes, Lecanoromycetes, Leotiomycetes, and Sordariomycetes of the Ascomycota, and Tremellomycetes and Cystobasidiomycetes of the Basidiomycota. The composition of major photobiont species and lichen-associated fungal community were mostly related to the mycobiont species. The contribution of growth forms or substrates on composition of photobiont and lichen-associated fungi was not evident.

  4. Cigarette Smoke-Exposed Candida albicans Increased Chitin Production and Modulated Human Fibroblast Cell Responses

    PubMed Central

    Alanazi, Humidah; Semlali, Abdelhabib; Perraud, Laura; Chmielewski, Witold; Zakrzewski, Andrew

    2014-01-01

    The predisposition of cigarette smokers for development of respiratory and oral bacterial infections is well documented. Cigarette smoke can also contribute to yeast infection. The aim of this study was to investigate the effect of cigarette smoke condensate (CSC) on C. albicans transition, chitin content, and response to environmental stress and to examine the interaction between CSC-pretreated C. albicans and normal human gingival fibroblasts. Following exposure to CSC, C. albicans transition from blastospore to hyphal form increased. CSC-pretreated yeast cells became significantly (P < 0.01) sensitive to oxidation but significantly (P < 0.01) resistant to both osmotic and heat stress. CSC-pretreated C. albicans expressed high levels of chitin, with 2- to 8-fold recorded under hyphal conditions. CSC-pretreated C. albicans adhered better to the gingival fibroblasts, proliferated almost three times more and adapted into hyphae, while the gingival fibroblasts recorded a significantly (P < 0.01) slow growth rate but a significantly higher level of IL-1β when in contact with CSC-pretreated C. albicans. CSC was thus able to modulate both C. albicans transition through the cell wall chitin content and the interaction between C. albicans and normal human gingival fibroblasts. These findings may be relevant to fungal infections in the oral cavity in smokers. PMID:25302312

  5. Cigarette smoke-exposed Candida albicans increased chitin production and modulated human fibroblast cell responses.

    PubMed

    Alanazi, Humidah; Semlali, Abdelhabib; Perraud, Laura; Chmielewski, Witold; Zakrzewski, Andrew; Rouabhia, Mahmoud

    2014-01-01

    The predisposition of cigarette smokers for development of respiratory and oral bacterial infections is well documented. Cigarette smoke can also contribute to yeast infection. The aim of this study was to investigate the effect of cigarette smoke condensate (CSC) on C. albicans transition, chitin content, and response to environmental stress and to examine the interaction between CSC-pretreated C. albicans and normal human gingival fibroblasts. Following exposure to CSC, C. albicans transition from blastospore to hyphal form increased. CSC-pretreated yeast cells became significantly (P < 0.01) sensitive to oxidation but significantly (P < 0.01) resistant to both osmotic and heat stress. CSC-pretreated C. albicans expressed high levels of chitin, with 2- to 8-fold recorded under hyphal conditions. CSC-pretreated C. albicans adhered better to the gingival fibroblasts, proliferated almost three times more and adapted into hyphae, while the gingival fibroblasts recorded a significantly (P < 0.01) slow growth rate but a significantly higher level of IL-1β when in contact with CSC-pretreated C. albicans. CSC was thus able to modulate both C. albicans transition through the cell wall chitin content and the interaction between C. albicans and normal human gingival fibroblasts. These findings may be relevant to fungal infections in the oral cavity in smokers.

  6. The use of displacement damage dose to correlate degradation in solar cells exposed to different radiations

    NASA Technical Reports Server (NTRS)

    Summers, Geoffrey P.; Burke, Edward A.; Shapiro, Philip; Statler, Richard; Messenger, Scott R.; Walters, Robert J.

    1994-01-01

    It has been found useful in the past to use the concept of 'equivalent fluence' to compare the radiation response of different solar cell technologies. Results are usually given in terms of an equivalent 1 MeV electron or an equivalent 10 MeV proton fluence. To specify cell response in a complex space-radiation environment in terms of an equivalent fluence, it is necessary to measure damage coefficients for a number of representative electron and proton energies. However, at the last Photovoltaic Specialist Conference we showed that nonionizing energy loss (NIEL) could be used to correlate damage coefficients for protons, using measurements for GaAs as an example. This correlation means that damage coefficients for all proton energies except near threshold can be predicted from a measurement made at one particular energy. NIEL is the exact equivalent for displacement damage of linear energy transfer (LET) for ionization energy loss. The use of NIEL in this way leads naturally to the concept of 10 MeV equivalent proton fluence. The situation for electron damage is more complex, however. It is shown that the concept of 'displacement damage dose' gives a more general way of unifying damage coefficients. It follows that 1 MeV electron equivalent fluence is a special case of a more general quantity for unifying electron damage coefficients which we call the 'effective 1 MeV electron equivalent dose'.

  7. Modeling the dose-response relationship for cytotoxicity of human cells exposed to chemical carcinogens. [N-acetoxy-2-acetylaminofluorene

    SciTech Connect

    Miller, J.H.; Heflich, R.H.

    1980-09-01

    Compounds like N-acetoxy-2-acetylaminofluorene (N-AcO-AAF) result from the in vivo reduction of nitrate derivatives of benzo(..cap alpha..)pyrene. The dose-response relationship for survival of cloning ability in human fibroblasts exposed to N-AcO-AAF is being investigated to obtain a better understanding of the carcinogenic potential of coal-related air pollutants. A model is presented which correlates the survival of normal human fibroblasts after exposure to N-AcO-AAF with the rate of excision of carcinogen residues bound to DNA. The model predicts that the survival of normal cells, S/sub N/, is related to the survival of repair deficient cells, S/sub XPA/, by the equation 1n(S/sub N/) = 1n(S/sub XPA/) (1-f) where f is the fraction of potentially lethal damage repaired in the normal cell at a given dose of carcinogen. The rate of excision of AAF residues from the DNA of confluent human fibroblasts was measured over the same dose range as the survival studies. This information together with the dose-response relationship for survival of normal and repair deficient cells permits a determination of the mean number of adducts required to produce a potentially lethal lesion and the effective time available for repair. The model can be used to predict the mean lifetime of carcinogen residues on the DNA of partially repair deficient cells and the effect of recovery on the survival of normal cells. Extensions of the model to account for shoulders on the dose-response relationship curves are also discussed.

  8. Analysis of the cellular stress response in MCF10A cells exposed to combined radio frequency radiation.

    PubMed

    Kim, Han-Na; Han, Na-Kyung; Hong, Mi-Na; Chi, Sung-Gil; Lee, Yun-Sil; Kim, Taehong; Pack, Jeong-Ki; Choi, Hyung-Do; Kim, Nam; Lee, Jae-Seon

    2012-01-01

    Exposure to environmental stressors can be measured by monitoring the cellular stress response in target cells. Here, we used the cellular stress response to investigate whether single or combined radio frequency (RF) radiation could induce stress response in human cells. Cellular stress responses in MCF10A human breast epithelial cells were characterized after exposure to 4 h of RF radiation [code division multiple access (CDMA) or CDMA plus wideband CDMA (WCDMA)] or 2 h RF radiation on 3 consecutive days. Specific absorption rate (SAR) was 4.0 W/kg for CDMA signal alone exposure and 2.0 W/kg each, 4.0 W/kg in total for combined CDMA plus WCDMA signals. Expression levels and phosphorylation states of specific heat shock proteins (HSPs) and mitogen-activated protein kinases (MAPKs) were analyzed by Western blot. It was found that HSP27 and ERK1/2 phosphorylations are the most sensitive markers of the stress response in MCF10A cells exposed to heat shock or ionizing radiation. Using these markers, we demonstrated that neither one-time nor repeated single (CDMA alone) or combined (CDMA plus WCDMA) RF radiation exposure significantly altered HSP27 and ERK1/2 phosphorylations in MCF10A cells (p > 0.05). The lack of a statistically significant alteration in HSP27 and ERK1/2 phosphorylations suggests that single or combined RF radiation exposure did not elicit activation of HSP27 and ERK1/2 in MCF10A cells.

  9. Caffeic Acid Reduces the Viability and Migration Rate of Oral Carcinoma Cells (SCC-25) Exposed to Low Concentrations of Ethanol

    PubMed Central

    Dziedzic, Arkadiusz; Kubina, Robert; Kabała-Dzik, Agata; Wojtyczka, Robert D.; Morawiec, Tadeusz; Bułdak, Rafał J.

    2014-01-01

    Alcohol increases the risk of carcinoma originated from oral epithelium, but the biological effects of ultra-low doses of ethanol on existing carcinoma cells in combination with natural substances are still unclear. A role for ethanol (EtOH), taken in small amounts as an ingredient of some beverages or mouthwashes to change the growth behavior of established squamous cell carcinoma, has still not been examined sufficiently. We designed an in vitro study to determine the effect of caffeic acid (CFA) on viability and migration ability of malignant oral epithelial keratinocytes, exposed to ultra-low concentrations (maximum 100 mmol/L) EtOH. MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-dimethyltetrazolium bromide) and LDH (lactate dehydrogenase) assays were used to assess the cytotoxic effect of EtOH/CFA and the viability of squamous carcinoma SCC-25 cells (ATCC CRL-1628, mobile part of the tongue). Tested EtOH concentrations were: 2.5, 5, 10, 25, 50, and 100 mmol/L, along with an equal CFA concentration of 50 μmol/L. Carcinoma cells’ migration was investigated by monolayer “wound” healing assay. We demonstrated that very low concentrations of EtOH ranging between 2.5 and 10 mmol/L may induce the viability of oral squamous cell carcinoma cells, while the results following addition of CFA reveal an antagonistic effect, attenuating pro-proliferative EtOH activity. The migration rate of oral squamous carcinoma cells can be significantly inhibited by the biological activity of caffeic acid. PMID:25329614

  10. Investigating longitudinal changes in the mechanical properties of MCF-7 cells exposed to paclitaxol using particle tracking microrheology

    NASA Astrophysics Data System (ADS)

    El Kaffas, Ahmed; Bekah, Devesh; Rui, Min; Kumaradas, J. Carl; Kolios, Michael C.

    2013-02-01

    Evidence suggests that compression and shear wave elastography are sensitive to the mechanical property changes occuring in dying cells following chemotherapy, and can hence be used to monitor cancer treatment response. A qualitative and quantitative understanding of the mechanical changes at the cellular level would allow to better infer how these changes affect macroscopic tissue mechanical properties and therefore allow the optimization of elastographic techniques (such as shear wave elastography) for the monitoring of cancer therapy. We used intracellular particle tracking microrheology (PTM) to investigate the mechanical property changes of cells exposed to paclitaxol, a mitotic inhibitor used in cancer chemotherapy. The average elastic and viscous moduli of the cytoplasm of treated MCF-7 breast cancer cells were calculated for frequency ranges between 0.2 and 100 rad s-1 (corresponding to 0.03 and 15.92 Hz, respectively). A significant increase in the complex shear modulus of the cell cytoplasm was detected at 12 h post treatment. At 24 h after drug exposure, the elastic and viscous moduli increased by a total of 191.3 Pa (>8000×) and 9 Pa (˜9×), respectively for low frequency shear modulus measurements (at 1 rad s-1). At higher frequencies (10 rad s-1), the elastic and viscous moduli increased by 188.5 Pa (˜60×) and 1.7 Pa (˜1.1×), respectively. Our work demonstrates that PTM can be used to measure changes in the mechanical properties of treated cells and that cell elasticity significantly increases by 24 h after chemotherapy exposure.

  11. Variations of algal communities cause darkening of a Greenland glacier.

    PubMed

    Lutz, Stefanie; Anesio, Alexandre M; Jorge Villar, Susana E; Benning, Liane G

    2014-08-01

    We have assessed the microbial ecology on the surface of Mittivakkat glacier in SE-Greenland during the exceptional high melting season in July 2012 when the so far most extreme melting rate for the Greenland Ice Sheet has been recorded. By employing a complementary and multi-disciplinary field sampling and analytical approach, we quantified the dramatic changes in the different microbial surface habitats (green snow, red snow, biofilms, grey ice, cryoconite holes). The observed clear change in dominant algal community and their rapidly changing cryo-organic adaptation inventory was linked to the high melting rate. The changes in carbon and nutrient fluxes between different microbial pools (from snow to ice, cryoconite holes and glacial forefronts) revealed that snow and ice algae dominate the net primary production at the onset of melting, and that they have the potential to support the cryoconite hole communities as carbon and nutrient sources. A large proportion of algal cells is retained on the glacial surface and temporal and spatial changes in pigmentation contribute to the darkening of the snow and ice surfaces. This implies that the fast, melt-induced algal growth has a high albedo reduction potential, and this may lead to a positive feedback speeding up melting processes.

  12. Harvesting algal biomass for biofuels using ultrafiltration membranes.

    PubMed

    Zhang, Xuezhi; Hu, Qiang; Sommerfeld, Milton; Puruhito, Emil; Chen, Yongsheng

    2010-07-01

    The objective of this paper is to develop efficient technologies for harvesting of algal biomass using membrane filtration. Foulants were characterized using scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Anti-fouling strategies were established, such as using air-assisted backwash with air scouring, and optimizing operational conditions. A model was also developed to predict the flux decline and final concentration based on a resistance-in-series analysis and a cake development calculation. The results showed that the buildup of the algal cake layer and adsorption of algogenic organic matter (AOM) (mainly protein, polysaccharides or polysaccharide-like substances) on the membrane caused membrane fouling. The cake layer buildup was removed by conducting an air-assisted backwash every 15 min. The adsorbed AOM could be removed by soaking the membrane in 400mg/L NaClO for 1h. In our experiment the algal suspension was concentrated 150 times, to give a final cell concentration of 154.85g/L. The harvesting efficiency and average flux were 46.01 g/(m(2)h) and 45.50 L/(m(2)h), respectively. No algae were found in the permeate, which had an average turbidity of 0.018 Nephelometric Turbidity Units (NTU). The flux decline predicted by the model under different conditions was consistent with the experimental results.

  13. Induction of Cell Death through Alteration of Oxidants and Antioxidants in Lung Epithelial Cells Exposed to High Energy Protons*

    PubMed Central

    Baluchamy, Sudhakar; Ravichandran, Prabakaran; Periyakaruppan, Adaikkappan; Ramesh, Vani; Hall, Joseph C.; Zhang, Ye; Jejelowo, Olufisayo; Gridley, Daila S.; Wu, Honglu; Ramesh, Govindarajan T.

    2010-01-01

    Radiation affects several cellular and molecular processes, including double strand breakage and modifications of sugar moieties and bases. In outer space, protons are the primary radiation source that poses a range of potential health risks to astronauts. On the other hand, the use of proton irradiation for tumor radiation therapy is increasing, as it largely spares healthy tissues while killing tumor tissues. Although radiation-related research has been conducted extensively, the molecular toxicology and cellular mechanisms affected by proton irradiation remain poorly understood. Therefore, in this study, we irradiated rat lung epithelial cells with different doses of protons and investigated their effects on cell proliferation and death. Our data show an inhibition of cell proliferation in proton-irradiated cells with a significant dose-dependent activation and repression of reactive oxygen species and antioxidants glutathione and superoxide dismutase, respectively, compared with control cells. In addition, the activities of apoptosis-related genes such as caspase-3 and -8 were induced in a dose-dependent manner with corresponding increased levels of DNA fragmentation in proton-irradiated cells compared with control cells. Together, our results show that proton irradiation alters oxidant and antioxidant levels in cells to activate the apoptotic pathway for cell death. PMID:20538614

  14. PI3K-Akt/PKB signaling pathway in neutrophils and mononuclear cells exposed to N-nitrosodimethylamine.

    PubMed

    Ratajczak-Wrona, Wioletta; Jablonska, Ewa; Garley, Marzena; Jablonski, Jakub; Radziwon, Piotr; Iwaniuk, Agnieszka; Grubczak, Kamil

    2014-01-01

    Neutrophils (PMN) play diverse regulatory and effector functions in the immune system through the release of reactive nitrogen species, including nitric oxide (NO). The enzyme responsible for NO synthesis in PMN is inducible nitric oxide synthase (iNOS) that is regulated by various signaling pathways, e.g. PI3K-Akt/PKB, and transcription factors. N-Nitrosodimethylamine (NDMA), a xenobiotic widespread in the human environment, affects immune cells. The study objective here was to examine the role of the PI3K-Akt/PKB pathway in induction of NO synthesis (with involvement of iNOS) in human PMN, as well as in autologous mononuclear cells (PBMC), exposed to NDMA. Isolated cells were incubated for 2 h with a sub-lethal dose of NDMA and then the expression of several select proteins in the cell cytoplasmic and nuclear fractions were determined by Western blot analyses. The results indicated that NDMA enhanced expression of iNOS, phospho-PI3K, and phospho-IκBα in the cytoplasmic fraction of the PMN and PBMC. The nuclear fraction of these cells also had a higher NF-κB expression. Moreover, in PMN, NDMA caused an increased expression of phospho-Akt (T308), phospho-Akt (S473), and phospho-IKKαβ in the cytoplasm, and c-Jun and FosB in the nuclear fraction. Blocking of PI3K caused a decrease in expression of all these proteins in NDMA-exposed PMN. However, inhibition of PI3K led to a drop in expression of iNOS, phospho-PI3K, and phospho-IκBα in the cytoplasm, and in NF-κB in the nuclear fraction, of PBMC. The results of these studies indicated to us that NDMA activates the PI3K-Akt/PKB pathway in human PMN and that this, in turn, contributes to the activation of transcription factors NF-κB, c-Jun, and FosB involved in NO production (through modulation of iNOS expression).

  15. Signalling of DNA damage and cytokines across cell barriers exposed to nanoparticles depends on barrier thickness

    NASA Astrophysics Data System (ADS)

    Sood, A.; Salih, S.; Roh, D.; Lacharme-Lora, L.; Parry, M.; Hardiman, B.; Keehan, R.; Grummer, R.; Winterhager, E.; Gokhale, P. J.; Andrews, P. W.; Abbott, C.; Forbes, K.; Westwood, M.; Aplin, J. D.; Ingham, E.; Papageorgiou, I.; Berry, M.; Liu, J.; Dick, A. D.; Garland, R. J.; Williams, N.; Singh, R.; Simon, A. K.; Lewis, M.; Ham, J.; Roger, L.; Baird, D. M.; Crompton, L. A.; Caldwell, M. A.; Swalwell, H.; Birch-Machin, M.; Lopez-Castejon, G.; Randall, A.; Lin, H.; Suleiman, M.-S.; Evans, W. H.; Newson, R.; Case, C. P.

    2011-12-01

    The use of nanoparticles in medicine is ever increasing, and it is important to understand their targeted and non-targeted effects. We have previously shown that nanoparticles can cause DNA damage to cells cultured below a cellular barrier without crossing this barrier. Here, we show that this indirect DNA damage depends on the thickness of the cellular barrier, and it is mediated by signalling through gap junction proteins following the generation of mitochondrial free radicals. Indirect damage was seen across both trophoblast and corneal barriers. Signalling, including cytokine release, occurred only across bilayer and multilayer barriers, but not across monolayer barriers. Indirect toxicity was also observed in mice and using ex vivo explants of the human placenta. If the importance of barrier thickness in signalling is a general feature for all types of barriers, our results may offer a principle with which to limit the adverse effects of nanoparticle exposure and offer new therapeutic approaches.

  16. S1P lyase in skeletal muscle regeneration and satellite cell activation: exposing the hidden lyase.

    PubMed

    Saba, Julie D; de la Garza-Rodea, Anabel S

    2013-01-01

    Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid whose actions are essential for many physiological processes including angiogenesis, lymphocyte trafficking and development. In addition, S1P serves as a muscle trophic factor that enables efficient muscle regeneration. This is due in part to S1P's ability to activate quiescent muscle stem cells called satellite cells (SCs) that are needed for muscle repair. However, the molecular mechanism by which S1P activates SCs has not been well understood. Further, strategies for harnessing S1P signaling to recruit SCs for therapeutic benefit have been lacking. S1P is irreversibly catabolized by S1P lyase (SPL), a highly conserved enzyme that catalyzes the cleavage of S1P at carbon bond C(2-3), resulting in formation of hexadecenal and ethanolamine-phosphate. SPL enhances apoptosis through substrate- and product-dependent events, thereby regulating cellular responses to chemotherapy, radiation and ischemia. SPL is undetectable in resting murine skeletal muscle. However, we recently found that SPL is dynamically upregulated in skeletal muscle after injury. SPL upregulation occurred in the context of a tightly orchestrated genetic program that resulted in a transient S1P signal in response to muscle injury. S1P activated quiescent SCs via a sphingosine-1-phosphate receptor 2 (S1P2)/signal transducer and activator of transcription 3 (STAT3)-dependent pathway, thereby facilitating skeletal muscle regeneration. Mdx mice, which serve as a model for muscular dystrophy (MD), exhibited skeletal muscle SPL upregulation and S1P deficiency. Pharmacological SPL inhibition raised skeletal muscle S1P levels, enhanced SC recruitment and improved mdx skeletal muscle regeneration. These findings reveal how S1P can activate SCs and indicate that SPL suppression may provide a therapeutic strategy for myopathies. This article is part of a Special Issue entitled Advances in Lysophospholipid Research.

  17. Protein profiles of cardiomyocyte differentiation in murine embryonic stem cells exposed to perfluorooctane sulfonate.

    PubMed

    Zhang, Ying-Ying; Tang, Lei-Lei; Zheng, Bei; Ge, Ren-Shan; Zhu, Dan-Yan

    2016-05-01

    Perfluorooctane sulfonate (PFOS) is a persistent organic contaminant that may affect diverse systems in animals and humans, including the cardiovascular system. However, little is known about the mechanism by which it affects the biological systems. Herein, we used embryonic stem cell test procedure as a tool to assess the developmental cardiotoxicity of PFOS. The differentially expressed proteins were identified by quantitative proteomics that combines the stable isotope labeling of amino acids with high-performance liquid chromatography-electrospray ionization tandem mass spectrometry. Results of the embryonic stem cell test procedure suggested that PFOS was a weak embryotoxic chemical. Nevertheless, a few marker proteins related to cardiovascular development (Brachyury, GATA4, MEF2C, α-actinin) were significantly reduced by exposure to PFOS. In total, 176 differential proteins were identified by proteomics analysis, of which 67 were upregulated and 109 were downregulated. Gene ontology annotation classified these proteins into 13 groups by molecular functions, 12 groups by cellular locations and 10 groups by biological processes. Most proteins were mainly relevant to either catalytic activity (25.6%), nucleus localization (28.9%) or to cellular component organization (19.8%). Pathway analysis revealed that 32 signaling pathways were affected, particularly these involved in metabolism. Changes in five proteins, including L-threonine dehydrogenase, X-ray repair cross-complementing 5, superoxide dismutase 2, and DNA methyltransferase 3b and 3a were confirmed by Western blotting, suggesting the reliability of the technique. These results revealed potential new targets of PFOS on the developmental cardiovascular system.

  18. Stimulation of production of prostaglandin E in gingival cells exposed to products of human blood mononuclear cells.

    PubMed Central

    D'Souza, S M; Englis, D J; Clark, A; Russell, R G

    1981-01-01

    1. Supernatant media from cultures of unstimulated human peripheral blood mononuclear cells contained one or more factors that increased by several hundred-fold the production of prostaglandin E by fibroblast-like cells derived from both inflamed and normal human gingival tissue. 2. This stimulation occurred in a dose-dependent manner and was completely inhibited by 14 microM-indomethacin. 3. Responsiveness to the factor declined as the age of the cell culture increased. 4. An increase in prostaglandin E production was first observed after a 2h exposure to the mononuclear cell factor(s) and could be prevented by cycloheximide. 5. Brief exposure (0.5 and 1.0 h) to mononuclear cell factor did not increase prostaglandin E production by the cells in a subsequent 72 h incubation in the absence of mononuclear cell factor. 6. Addition of arachidonate (10 microM and 15 microM) further enhanced stimulation of prostaglandin E production in response to mononuclear cell factor. 7. The stimulatory activity was resistant to digestion by trypsin, but was heat-labile, so that only 17% remained after treatment at 56 degrees C for 30 min. PMID:6798975

  19. Stimulation of production of prostaglandin E in gingival cells exposed to products of human blood mononuclear cells.

    PubMed

    D'Souza, S M; Englis, D J; Clark, A; Russell, R G

    1981-08-15

    1. Supernatant media from cultures of unstimulated human peripheral blood mononuclear cells contained one or more factors that increased by several hundred-fold the production of prostaglandin E by fibroblast-like cells derived from both inflamed and normal human gingival tissue. 2. This stimulation occurred in a dose-dependent manner and was completely inhibited by 14 microM-indomethacin. 3. Responsiveness to the factor declined as the age of the cell culture increased. 4. An increase in prostaglandin E production was first observed after a 2h exposure to the mononuclear cell factor(s) and could be prevented by cycloheximide. 5. Brief exposure (0.5 and 1.0 h) to mononuclear cell factor did not increase prostaglandin E production by the cells in a subsequent 72 h incubation in the absence of mononuclear cell factor. 6. Addition of arachidonate (10 microM and 15 microM) further enhanced stimulation of prostaglandin E production in response to mononuclear cell factor. 7. The stimulatory activity was resistant to digestion by trypsin, but was heat-labile, so that only 17% remained after treatment at 56 degrees C for 30 min.

  20. Radiosensitivity of hepatoma cell lines and human normal liver cell lines exposed to 12C6+ ions

    NASA Astrophysics Data System (ADS)

    Jing, X.; Yang, J.; Li, W.; Guo, C.; Dang, B.; Wang, J.; Zhou, L.; Wei, W.; Gao, Q.

    AIM To investigate the radiosensitivity of hepatoma cell lines and human normal liver cell lines METHODS Accelerated carbon ions by heavy ion research facility in Lanzhou HIRFL have high LET We employed it to study the radiosensitivity of hepatoma cell lines SMMC-7721 and human normal liver cell lines L02 using premature chromosome condensation technique PCC Cell survive was documented by a colony assay Chromatid breaks were measured by counting the number of chromatid breaks and isochromatid breaks immediately after prematurely chromosome condensed by Calyculin-A RESULTS The survival curve of the two cell lines presented a good linear relationship and the survival fraction of L02 is higher than that of SMMC-7721 Additionally the two types of G 2 phase chromosome breaks chromatid breaks and isochromatid breaks of L02 are lower than that of SMMC-7721 CONCLUSION Human normal liver cell line have high radioresistance than that of hepatoma cell line It imply that it is less damage to normal organs when radiotherapy to hepatoma

  1. Cell Structural Changes in the Needles of Norway Spruce Exposed to Long‐term Ozone and Drought

    PubMed Central

    KIVIMÄENPÄÄ, MINNA; SUTINEN, SIRKKA; KARLSSON, PER ERIK; SELLDÉN, GUN

    2003-01-01

    Effects of ozone and/or drought on Norway spruce needles were studied using light microscopy and electron microscopy. Saplings were exposed to ozone in open‐top chambers during 1992–1995 and also to drought in the late summers of 1993–1995. Samples from current and previous year needles were collected five times during 1995. Ozone increased the numbers of peroxisomes and mitochondria, which suggests that defence mechanisms against oxidative stress were active. The results from peroxisomes suggest that the oxidative stress was more pronounced in the upper side of the needles, and those from mitochondria that defence was more active in the younger needle generation. Possibly due to the good nitrogen status and the active defence, no ozone‐specific chloroplast alterations were seen. At the end of the season, older needles from ozone treatments had smaller central vacuoles compared with other needles. Cytoplasmic vacuoles around the nucleus were increased by ozone in the beginning of the experiment, and did not increase towards the end of the season as in the controls. These results from vacuoles may indicate that ozone affected the osmotic properties of the cells. Decreased number and underdevelopment of sclerenchyma cells and proliferation of tonoplast were related to nutrient imbalance, which was enhanced by drought. Larger vascular cylinders and more effective starch accumulation before and after the drought periods compensated for the reduced water status. Numbers of peroxisomes and mitochondria were increased in the drought‐exposed needles before the onset of drought treatments of the study year, i.e. these changes were memory effects. Interactions between ozone and drought were few. PMID:14576076

  2. Tubular photobioreactor design for algal cultures.

    PubMed

    Molina, E; Fernández, J; Acién, F G; Chisti, Y

    2001-12-28

    Principles of fluid mechanics, gas-liquid mass transfer, and irradiance controlled algal growth are integrated into a method for designing tubular photobioreactors in which the culture is circulated by an airlift pump. A 0.2 m(3) photobioreactor designed using the proposed approach was proved in continuous outdoor culture of the microalga Phaeodactylum tricornutum. The culture performance was assessed under various conditions of irradiance, dilution rates and liquid velocities through the tubular solar collector. A biomass productivity of 1.90 g l(-1) d(-1) (or 32 g m(-2) d(-1)) could be obtained at a dilution rate of 0.04 h(-1). Photoinhibition was observed during hours of peak irradiance; the photosynthetic activity of the cells recovered a few hours later. Linear liquid velocities of 0.50 and 0.35 m s(-1) in the solar collector gave similar biomass productivities, but the culture collapsed at lower velocities. The effect of dissolved oxygen concentration on productivity was quantified in indoor conditions; dissolved oxygen levels higher or lower than air saturation values reduced productivity. Under outdoor conditions, for given levels of oxygen supersaturation, the productivity decline was greater outdoors than indoors, suggesting that under intense outdoor illumination photooxidation contributed to loss of productivity in comparison with productivity loss due to oxygen inhibition alone. Dissolved oxygen values at the outlet of solar collector tube were up to 400% of air saturation.

  3. Genomic Profiling of a Human Leukemic Monocytic Cell-Line (THP-1) Exposed to Alpha Particle Radiation

    PubMed Central

    Chauhan, Vinita; Howland, Matthew

    2012-01-01

    This study examined alpha (α-) particle radiation effects on global changes in gene expression in human leukemic monocytic cells (THP-1) for the purposes of mining for candidate biomarkers that could be used for the development of a biological assessment tool. THP-1 cells were exposed to α-particle radiation at a dose range of 0 to 1.5 Gy. Twenty-four hours and three days after exposure gene expression was monitored using microarray technology. A total of 16 genes were dose responsive and classified as early onset due to their expression 24 h after exposure. Forty-eight transcripts were dose responsive and classified as late-onset as they were expressed 72 h after exposure. Among these genes, 6 genes were time and dose responsive and validated further using alternate technology. These transcripts were upregulated and associated with biological processes related to immune function, organelle stability and cell signalling/communication. This panel of genes merits further validation to determine if they are strong candidate biomarkers indicative of α-particle exposure. PMID:23097634

  4. Activation of eNOS in endothelial cells exposed to ionizing radiation involves components of the DNA damage response pathway

    SciTech Connect

    Nagane, Masaki; Yasui, Hironobu; Sakai, Yuri; Yamamori, Tohru; Niwa, Koichi; Hattori, Yuichi; Kondo, Takashi; Inanami, Osamu

    2015-01-02

    Highlights: • eNOS activity is increased in BAECs exposed to X-rays. • ATM is involved in this increased eNOS activity. • HSP90 modulates the radiation-induced activation of ATM and eNOS. - Abstract: In this study, the involvement of ataxia telangiectasia mutated (ATM) kinase and heat shock protein 90 (HSP90) in endothelial nitric oxide synthase (eNOS) activation was investigated in X-irradiated bovine aortic endothelial cells. The activity of nitric oxide synthase (NOS) and the phosphorylation of serine 1179 of eNOS (eNOS-Ser1179) were significantly increased in irradiated cells. The radiation-induced increases in NOS activity and eNOS-Ser1179 phosphorylation levels were significantly reduced by treatment with either an ATM inhibitor (Ku-60019) or an HSP90 inhibitor (geldanamycin). Geldanamycin was furthermore found to suppress the radiation-induced phosphorylation of ATM-Ser1181. Our results indicate that the radiation-induced eNOS activation in bovine aortic endothelial cells is regulated by ATM and HSP90.

  5. Comparison of autosomal mutations in mouse kidney epithelial cells exposed to iron ions in situ or in culture.

    PubMed

    Turker, Mitchell S; Connolly, Lanelle; Dan, Cristian; Lasarev, Michael; Gauny, Stacey; Kwoh, Ely; Kronenberg, Amy

    2009-11-01

    Exposure to accelerated iron ions represents a significant health risk in the deep space environment because it induces mutations that can cause cancer. A mutation assay was used to determine the full spectrum of autosomal mutations induced by exposure to 2 Gy of 1 GeV/nucleon iron ions in intact kidney epithelium, and the results were compared with mutations induced in cells of a kidney epithelial cell line exposed in vitro. A molecular analysis for loss of heterozygosity (LOH) for polymorphic loci on chromosome 8, which harbors Aprt, demonstrated iron-ion induction of mitotic recombination, interstitial deletion, and discontinuous LOH events. Iron-ion-induced deletions were detected more readily with the in vitro assay, whereas discontinuous LOH was detected more readily in the intact kidney. The specific induction of discontinuous LOH in vivo suggests that this mutation pattern may serve as an indicator of genomic instability. Interestingly, the frequency of small intragenic events increased as a function of time after exposure, suggesting non-targeted effects. In total, the results demonstrate that 1 GeV/nucleon iron ions can elicit a variety of autosomal mutations and that the cellular microenvironment and the sampling time after exposure can influence the distribution of these mutations in epithelial cell populations.

  6. Protein kinase C activity is altered in HL60 cells exposed to 60 Hz AC electric fields

    SciTech Connect

    Holian, O.; Reyes, H.M.; Attar, B.M.; Walter, R.J.; Astumian, R.D.; Lee, R.C.

    1996-12-31

    The authors examined the effects of electric fields (EFs) on the activity and subcellular distribution of protein kinase C (PKC) of living HL60 cells. Sixty Hertz AC sinusoidal EFs (1.5--1,000 mV/cm p-p) were applied for 1 h to cells (10{sup 7}/ml) in Teflon chambers at 37 C in the presence or absence of 2 {micro}M phorbol 12-myristate 13-acetate (PMA). PMA stimulation alone evoked intracellular translocation of PKC from the cytosolic to particulate fractions. In cells that were exposed to EFs (100--1,000 mV/cm) without PMA, a loss of PKC activity from the cytosol, but no concomitant rise in particulate PKC activity, was observed. In the presence of PMA, EFs (33--330 mV/cm) also accentuated the expected loss of PKC activity from the cytosol and augmented the rise in PKC activity in the particulate fraction. These data show that EFs alone or combined with PMA promote down-regulation of cytosolic PKC activity similar to that evoked by mitogens and tumor promoters but that it does not elicit the concomitant rise in particulate activity seen with those agents.

  7. No DNA damage response and negligible genome-wide transcriptional changes in human embryonic stem cells exposed to terahertz radiation.

    PubMed

    Bogomazova, A N; Vassina, E M; Goryachkovskaya, T N; Popik, V M; Sokolov, A S; Kolchanov, N A; Lagarkova, M A; Kiselev, S L; Peltek, S E

    2015-01-13

    Terahertz (THz) radiation was proposed recently for use in various applications, including medical imaging and security scanners. However, there are concerns regarding the possible biological effects of non-ionising electromagnetic radiation in the THz range on cells. Human embryonic stem cells (hESCs) are extremely sensitive to environmental stimuli, and we therefore utilised this cell model to investigate the non-thermal effects of THz irradiation. We studied DNA damage and transcriptome responses in hESCs exposed to narrow-band THz radiation (2.3 THz) under strict temperature control. The transcription of approximately 1% of genes was subtly increased following THz irradiation. Functional annotation enrichment analysis of differentially expressed genes revealed 15 functional classes, which were mostly related to mitochondria. Terahertz irradiation did not induce the formation of γH2AX foci or structural chromosomal aberrations in hESCs. We did not observe any effect on the mitotic index or morphology of the hESCs following THz exposure.

  8. Cytotoxicity, oxidative stress, and genotoxicity in human hepatocyte and embryonic kidney cells exposed to ZnO nanoparticles