The Experts below are selected from a list of 42375 Experts worldwide ranked by ideXlab platform
Bradley R Ringeisen - One of the best experts on this subject based on the ideXlab platform.
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the influence of acidity on microbial fuel cells containing shewanella oneidensis
Biosensors and Bioelectronics, 2008Co-Authors: Justin C Biffinger, Jeremy J Pietron, Orianna Bretschger, Lloyd J Nadeau, Glenn R Johnson, Cynthia C Williams, Kenneth H Nealson, Bradley R RingeisenAbstract:Microbial fuel cells (MFCs) traditionally operate at pH values between 6 and 8. However, the effect of pH on the growth and electron transfer abilities of Shewanella oneidensis MR-1 (wild-type) and DSP10 (spontaneous mutant), bacteria commonly used in MFCs, to electrodes has not been examined. Minia- ture MFCs using bare graphite felt electrodes and nanoporous polycarbonate membranes with MR-1 or DSP10 cultures generated >8 W/m 3 and ∼400A between pH 6-7. The DSP10 strain significantly outper- formed MR-1 at neutral pH but underperformed at pH 5. Higher concentrations of DSP10 were sustained at pH 7 relative to that of MR-1, whereas at pH 5 this trend was reversed indicating that cell count was not solely responsible for the observed differences in current. S. oneidensis MR-1 was determined to be more suitable than DSP10 for MFCs with elevated acidity levels. The concentration of riboflavin in the bacterial cultures was reduced significantly at pH 5 for DSP10, as determined by high performance liquid chromatography (HPLC) of the filter sterilized growth media. In addition, these results suggest that medi- ator biosynthesis and not solely bacterial concentration plays a significant role in current output from S. oneidensis containing MFCs. Published by Elsevier B.V.
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a miniature microbial fuel cell operating with an aerobic anode chamber
Journal of Power Sources, 2007Co-Authors: Bradley R Ringeisen, Ricky Ray, Brenda J LittleAbstract:A miniature microbial fuel cell (mini-MFC) is described that utilizes an aerobic culture of Shewanella oneidensis DSP10 as the active electrochemical species in the anode chamber. We find that the maximum aerobic mini-MFC power without the addition of exogenous mediators was 0.40 mW, a 33% decrease when compared with an anaerobic DSP10 culture (0.6 mW) operating in the mini-MFC. This decrease is most likely due to the presence of dissolved oxygen in the anode chamber that scavenges electrons to form water, thereby reducing the number of electrons donated to the anode. Aerobic power and current density at maximum power using the true surface area of the anode (611 cm 2 ) were calculated to be 6.5 mW m −2 and 13 mA m −2 . The power density rises to 2.0 W m −2 and 330 W m −3 when calculated using the cross-sectional area and volume of the device (2 cm 2 , 1.2 cm 3 ). The Coulombic efficiency was also reduced from 11 to 5% when using the aerobic versus anaerobic culture. Similar results were found when the external mediator anthraquinone-2,6-disulfonate (AQDS) was added to the aerobic culture, resulting in a maximum power of 0.54 mW, a 37% drop in power when compared to the anaerobic mediated system. Published by Elsevier B.V.
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a miniature microbial fuel cell operating with an aerobic anode chamber
Journal of Power Sources, 2007Co-Authors: Bradley R Ringeisen, Ricky Ray, Brenda J LittleAbstract:Abstract A miniature microbial fuel cell (mini-MFC) is described that utilizes an aerobic culture of Shewanella oneidensis DSP10 as the active electrochemical species in the anode chamber. We find that the maximum aerobic mini-MFC power without the addition of exogenous mediators was 0.40 mW, a 33% decrease when compared with an anaerobic DSP10 culture (0.6 mW) operating in the mini-MFC. This decrease is most likely due to the presence of dissolved oxygen in the anode chamber that scavenges electrons to form water, thereby reducing the number of electrons donated to the anode. Aerobic power and current density at maximum power using the true surface area of the anode (611 cm2) were calculated to be 6.5 mW m−2 and 13 mA m−2. The power density rises to 2.0 W m−2 and 330 W m−3 when calculated using the cross-sectional area and volume of the device (2 cm2, 1.2 cm3). The Coulombic efficiency was also reduced from 11 to 5% when using the aerobic versus anaerobic culture. Similar results were found when the external mediator anthraquinone-2,6-disulfonate (AQDS) was added to the aerobic culture, resulting in a maximum power of 0.54 mW, a 37% drop in power when compared to the anaerobic mediated system.
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a biofilm enhanced miniature microbial fuel cell using shewanella oneidensis dsp10 and oxygen reduction cathodes
Biosensors and Bioelectronics, 2007Co-Authors: Justin C Biffinger, Brenda J Little, Ricky Ray, Jeremy J Pietron, Bradley R RingeisenAbstract:Abstract A miniature-microbial fuel cell (mini-MFC, chamber volume: 1.2 mL) was used to monitor biofilm development from a pure culture of Shewanella oneidensis DSP10 on graphite felt (GF) under minimal nutrient conditions. ESEM evidence of biofilm formation on GF is supported by substantial power density (per device cross-section) from the mini-MFC when using an acellular minimal media anolyte (1500 mW/m 2 ). These experiments demonstrate that power density per volume for a biofilm flow reactor MFC should be calculated using the anode chamber volume alone (250 W/m 3 ), rather than with the full anolyte volume. Two oxygen reduction cathodes (uncoated GF or a Pt/vulcanized carbon coating on GF) were also compared to a cathode using uncoated GF and a 50 mM ferricyanide catholyte solution. The Pt/C-GF (2–4% Pt by mass) electrodes with liquid cultures of DSP10 produced one order of magnitude larger power density (150 W/m 3 ) than bare graphite felt (12 W/m 3 ) in this design. These advances are some of the required modifications to enable the mini-MFC to be used in real-time, long-term environmental power generating situations.
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a biofilm enhanced miniature microbial fuel cell using shewanella oneidensis dsp10 and oxygen reduction cathodes
Biosensors and Bioelectronics, 2007Co-Authors: Justin C Biffinger, Jeremy J Pietron, Brenda J Little, Bradley R RingeisenAbstract:Abstract A miniature-microbial fuel cell (mini-MFC, chamber volume: 1.2 mL) was used to monitor biofilm development from a pure culture of Shewanella oneidensis DSP10 on graphite felt (GF) under minimal nutrient conditions. ESEM evidence of biofilm formation on GF is supported by substantial power density (per device cross-section) from the mini-MFC when using an acellular minimal media anolyte (1500 mW/m 2 ). These experiments demonstrate that power density per volume for a biofilm flow reactor MFC should be calculated using the anode chamber volume alone (250 W/m 3 ), rather than with the full anolyte volume. Two oxygen reduction cathodes (uncoated GF or a Pt/vulcanized carbon coating on GF) were also compared to a cathode using uncoated GF and a 50 mM ferricyanide catholyte solution. The Pt/C-GF (2–4% Pt by mass) electrodes with liquid cultures of DSP10 produced one order of magnitude larger power density (150 W/m 3 ) than bare graphite felt (12 W/m 3 ) in this design. These advances are some of the required modifications to enable the mini-MFC to be used in real-time, long-term environmental power generating situations.
Brenda J Little - One of the best experts on this subject based on the ideXlab platform.
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a miniature microbial fuel cell operating with an aerobic anode chamber
Journal of Power Sources, 2007Co-Authors: Bradley R Ringeisen, Ricky Ray, Brenda J LittleAbstract:A miniature microbial fuel cell (mini-MFC) is described that utilizes an aerobic culture of Shewanella oneidensis DSP10 as the active electrochemical species in the anode chamber. We find that the maximum aerobic mini-MFC power without the addition of exogenous mediators was 0.40 mW, a 33% decrease when compared with an anaerobic DSP10 culture (0.6 mW) operating in the mini-MFC. This decrease is most likely due to the presence of dissolved oxygen in the anode chamber that scavenges electrons to form water, thereby reducing the number of electrons donated to the anode. Aerobic power and current density at maximum power using the true surface area of the anode (611 cm 2 ) were calculated to be 6.5 mW m −2 and 13 mA m −2 . The power density rises to 2.0 W m −2 and 330 W m −3 when calculated using the cross-sectional area and volume of the device (2 cm 2 , 1.2 cm 3 ). The Coulombic efficiency was also reduced from 11 to 5% when using the aerobic versus anaerobic culture. Similar results were found when the external mediator anthraquinone-2,6-disulfonate (AQDS) was added to the aerobic culture, resulting in a maximum power of 0.54 mW, a 37% drop in power when compared to the anaerobic mediated system. Published by Elsevier B.V.
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a miniature microbial fuel cell operating with an aerobic anode chamber
Journal of Power Sources, 2007Co-Authors: Bradley R Ringeisen, Ricky Ray, Brenda J LittleAbstract:Abstract A miniature microbial fuel cell (mini-MFC) is described that utilizes an aerobic culture of Shewanella oneidensis DSP10 as the active electrochemical species in the anode chamber. We find that the maximum aerobic mini-MFC power without the addition of exogenous mediators was 0.40 mW, a 33% decrease when compared with an anaerobic DSP10 culture (0.6 mW) operating in the mini-MFC. This decrease is most likely due to the presence of dissolved oxygen in the anode chamber that scavenges electrons to form water, thereby reducing the number of electrons donated to the anode. Aerobic power and current density at maximum power using the true surface area of the anode (611 cm2) were calculated to be 6.5 mW m−2 and 13 mA m−2. The power density rises to 2.0 W m−2 and 330 W m−3 when calculated using the cross-sectional area and volume of the device (2 cm2, 1.2 cm3). The Coulombic efficiency was also reduced from 11 to 5% when using the aerobic versus anaerobic culture. Similar results were found when the external mediator anthraquinone-2,6-disulfonate (AQDS) was added to the aerobic culture, resulting in a maximum power of 0.54 mW, a 37% drop in power when compared to the anaerobic mediated system.
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a biofilm enhanced miniature microbial fuel cell using shewanella oneidensis dsp10 and oxygen reduction cathodes
Biosensors and Bioelectronics, 2007Co-Authors: Justin C Biffinger, Brenda J Little, Ricky Ray, Jeremy J Pietron, Bradley R RingeisenAbstract:Abstract A miniature-microbial fuel cell (mini-MFC, chamber volume: 1.2 mL) was used to monitor biofilm development from a pure culture of Shewanella oneidensis DSP10 on graphite felt (GF) under minimal nutrient conditions. ESEM evidence of biofilm formation on GF is supported by substantial power density (per device cross-section) from the mini-MFC when using an acellular minimal media anolyte (1500 mW/m 2 ). These experiments demonstrate that power density per volume for a biofilm flow reactor MFC should be calculated using the anode chamber volume alone (250 W/m 3 ), rather than with the full anolyte volume. Two oxygen reduction cathodes (uncoated GF or a Pt/vulcanized carbon coating on GF) were also compared to a cathode using uncoated GF and a 50 mM ferricyanide catholyte solution. The Pt/C-GF (2–4% Pt by mass) electrodes with liquid cultures of DSP10 produced one order of magnitude larger power density (150 W/m 3 ) than bare graphite felt (12 W/m 3 ) in this design. These advances are some of the required modifications to enable the mini-MFC to be used in real-time, long-term environmental power generating situations.
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a biofilm enhanced miniature microbial fuel cell using shewanella oneidensis dsp10 and oxygen reduction cathodes
Biosensors and Bioelectronics, 2007Co-Authors: Justin C Biffinger, Jeremy J Pietron, Brenda J Little, Bradley R RingeisenAbstract:Abstract A miniature-microbial fuel cell (mini-MFC, chamber volume: 1.2 mL) was used to monitor biofilm development from a pure culture of Shewanella oneidensis DSP10 on graphite felt (GF) under minimal nutrient conditions. ESEM evidence of biofilm formation on GF is supported by substantial power density (per device cross-section) from the mini-MFC when using an acellular minimal media anolyte (1500 mW/m 2 ). These experiments demonstrate that power density per volume for a biofilm flow reactor MFC should be calculated using the anode chamber volume alone (250 W/m 3 ), rather than with the full anolyte volume. Two oxygen reduction cathodes (uncoated GF or a Pt/vulcanized carbon coating on GF) were also compared to a cathode using uncoated GF and a 50 mM ferricyanide catholyte solution. The Pt/C-GF (2–4% Pt by mass) electrodes with liquid cultures of DSP10 produced one order of magnitude larger power density (150 W/m 3 ) than bare graphite felt (12 W/m 3 ) in this design. These advances are some of the required modifications to enable the mini-MFC to be used in real-time, long-term environmental power generating situations.
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high power density from a miniature microbial fuel cell using shewanella oneidensis dsp10
Environmental Science & Technology, 2006Co-Authors: Bradley R Ringeisen, Ricky Ray, Brenda J Little, Emily Henderson, Jeremy J Pietron, Justin C Biffinger, Joanne JonesmeehanAbstract:A miniature microbial fuel cell (mini-MFC) is described that demonstrates high output power per device cross-section (2.0 cm2) and volume (1.2 cm3). Shewanella oneidensis DSP10 in growth medium wit...
Justin C Biffinger - One of the best experts on this subject based on the ideXlab platform.
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the influence of acidity on microbial fuel cells containing shewanella oneidensis
Biosensors and Bioelectronics, 2008Co-Authors: Justin C Biffinger, Jeremy J Pietron, Orianna Bretschger, Lloyd J Nadeau, Glenn R Johnson, Cynthia C Williams, Kenneth H Nealson, Bradley R RingeisenAbstract:Microbial fuel cells (MFCs) traditionally operate at pH values between 6 and 8. However, the effect of pH on the growth and electron transfer abilities of Shewanella oneidensis MR-1 (wild-type) and DSP10 (spontaneous mutant), bacteria commonly used in MFCs, to electrodes has not been examined. Minia- ture MFCs using bare graphite felt electrodes and nanoporous polycarbonate membranes with MR-1 or DSP10 cultures generated >8 W/m 3 and ∼400A between pH 6-7. The DSP10 strain significantly outper- formed MR-1 at neutral pH but underperformed at pH 5. Higher concentrations of DSP10 were sustained at pH 7 relative to that of MR-1, whereas at pH 5 this trend was reversed indicating that cell count was not solely responsible for the observed differences in current. S. oneidensis MR-1 was determined to be more suitable than DSP10 for MFCs with elevated acidity levels. The concentration of riboflavin in the bacterial cultures was reduced significantly at pH 5 for DSP10, as determined by high performance liquid chromatography (HPLC) of the filter sterilized growth media. In addition, these results suggest that medi- ator biosynthesis and not solely bacterial concentration plays a significant role in current output from S. oneidensis containing MFCs. Published by Elsevier B.V.
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a biofilm enhanced miniature microbial fuel cell using shewanella oneidensis dsp10 and oxygen reduction cathodes
Biosensors and Bioelectronics, 2007Co-Authors: Justin C Biffinger, Brenda J Little, Ricky Ray, Jeremy J Pietron, Bradley R RingeisenAbstract:Abstract A miniature-microbial fuel cell (mini-MFC, chamber volume: 1.2 mL) was used to monitor biofilm development from a pure culture of Shewanella oneidensis DSP10 on graphite felt (GF) under minimal nutrient conditions. ESEM evidence of biofilm formation on GF is supported by substantial power density (per device cross-section) from the mini-MFC when using an acellular minimal media anolyte (1500 mW/m 2 ). These experiments demonstrate that power density per volume for a biofilm flow reactor MFC should be calculated using the anode chamber volume alone (250 W/m 3 ), rather than with the full anolyte volume. Two oxygen reduction cathodes (uncoated GF or a Pt/vulcanized carbon coating on GF) were also compared to a cathode using uncoated GF and a 50 mM ferricyanide catholyte solution. The Pt/C-GF (2–4% Pt by mass) electrodes with liquid cultures of DSP10 produced one order of magnitude larger power density (150 W/m 3 ) than bare graphite felt (12 W/m 3 ) in this design. These advances are some of the required modifications to enable the mini-MFC to be used in real-time, long-term environmental power generating situations.
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a biofilm enhanced miniature microbial fuel cell using shewanella oneidensis dsp10 and oxygen reduction cathodes
Biosensors and Bioelectronics, 2007Co-Authors: Justin C Biffinger, Jeremy J Pietron, Brenda J Little, Bradley R RingeisenAbstract:Abstract A miniature-microbial fuel cell (mini-MFC, chamber volume: 1.2 mL) was used to monitor biofilm development from a pure culture of Shewanella oneidensis DSP10 on graphite felt (GF) under minimal nutrient conditions. ESEM evidence of biofilm formation on GF is supported by substantial power density (per device cross-section) from the mini-MFC when using an acellular minimal media anolyte (1500 mW/m 2 ). These experiments demonstrate that power density per volume for a biofilm flow reactor MFC should be calculated using the anode chamber volume alone (250 W/m 3 ), rather than with the full anolyte volume. Two oxygen reduction cathodes (uncoated GF or a Pt/vulcanized carbon coating on GF) were also compared to a cathode using uncoated GF and a 50 mM ferricyanide catholyte solution. The Pt/C-GF (2–4% Pt by mass) electrodes with liquid cultures of DSP10 produced one order of magnitude larger power density (150 W/m 3 ) than bare graphite felt (12 W/m 3 ) in this design. These advances are some of the required modifications to enable the mini-MFC to be used in real-time, long-term environmental power generating situations.
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high power density from a miniature microbial fuel cell using shewanella oneidensis dsp10
Environmental Science & Technology, 2006Co-Authors: Bradley R Ringeisen, Ricky Ray, Brenda J Little, Emily Henderson, Jeremy J Pietron, Justin C Biffinger, Joanne JonesmeehanAbstract:A miniature microbial fuel cell (mini-MFC) is described that demonstrates high output power per device cross-section (2.0 cm2) and volume (1.2 cm3). Shewanella oneidensis DSP10 in growth medium wit...
Ricky Ray - One of the best experts on this subject based on the ideXlab platform.
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a miniature microbial fuel cell operating with an aerobic anode chamber
Journal of Power Sources, 2007Co-Authors: Bradley R Ringeisen, Ricky Ray, Brenda J LittleAbstract:A miniature microbial fuel cell (mini-MFC) is described that utilizes an aerobic culture of Shewanella oneidensis DSP10 as the active electrochemical species in the anode chamber. We find that the maximum aerobic mini-MFC power without the addition of exogenous mediators was 0.40 mW, a 33% decrease when compared with an anaerobic DSP10 culture (0.6 mW) operating in the mini-MFC. This decrease is most likely due to the presence of dissolved oxygen in the anode chamber that scavenges electrons to form water, thereby reducing the number of electrons donated to the anode. Aerobic power and current density at maximum power using the true surface area of the anode (611 cm 2 ) were calculated to be 6.5 mW m −2 and 13 mA m −2 . The power density rises to 2.0 W m −2 and 330 W m −3 when calculated using the cross-sectional area and volume of the device (2 cm 2 , 1.2 cm 3 ). The Coulombic efficiency was also reduced from 11 to 5% when using the aerobic versus anaerobic culture. Similar results were found when the external mediator anthraquinone-2,6-disulfonate (AQDS) was added to the aerobic culture, resulting in a maximum power of 0.54 mW, a 37% drop in power when compared to the anaerobic mediated system. Published by Elsevier B.V.
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a miniature microbial fuel cell operating with an aerobic anode chamber
Journal of Power Sources, 2007Co-Authors: Bradley R Ringeisen, Ricky Ray, Brenda J LittleAbstract:Abstract A miniature microbial fuel cell (mini-MFC) is described that utilizes an aerobic culture of Shewanella oneidensis DSP10 as the active electrochemical species in the anode chamber. We find that the maximum aerobic mini-MFC power without the addition of exogenous mediators was 0.40 mW, a 33% decrease when compared with an anaerobic DSP10 culture (0.6 mW) operating in the mini-MFC. This decrease is most likely due to the presence of dissolved oxygen in the anode chamber that scavenges electrons to form water, thereby reducing the number of electrons donated to the anode. Aerobic power and current density at maximum power using the true surface area of the anode (611 cm2) were calculated to be 6.5 mW m−2 and 13 mA m−2. The power density rises to 2.0 W m−2 and 330 W m−3 when calculated using the cross-sectional area and volume of the device (2 cm2, 1.2 cm3). The Coulombic efficiency was also reduced from 11 to 5% when using the aerobic versus anaerobic culture. Similar results were found when the external mediator anthraquinone-2,6-disulfonate (AQDS) was added to the aerobic culture, resulting in a maximum power of 0.54 mW, a 37% drop in power when compared to the anaerobic mediated system.
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a biofilm enhanced miniature microbial fuel cell using shewanella oneidensis dsp10 and oxygen reduction cathodes
Biosensors and Bioelectronics, 2007Co-Authors: Justin C Biffinger, Brenda J Little, Ricky Ray, Jeremy J Pietron, Bradley R RingeisenAbstract:Abstract A miniature-microbial fuel cell (mini-MFC, chamber volume: 1.2 mL) was used to monitor biofilm development from a pure culture of Shewanella oneidensis DSP10 on graphite felt (GF) under minimal nutrient conditions. ESEM evidence of biofilm formation on GF is supported by substantial power density (per device cross-section) from the mini-MFC when using an acellular minimal media anolyte (1500 mW/m 2 ). These experiments demonstrate that power density per volume for a biofilm flow reactor MFC should be calculated using the anode chamber volume alone (250 W/m 3 ), rather than with the full anolyte volume. Two oxygen reduction cathodes (uncoated GF or a Pt/vulcanized carbon coating on GF) were also compared to a cathode using uncoated GF and a 50 mM ferricyanide catholyte solution. The Pt/C-GF (2–4% Pt by mass) electrodes with liquid cultures of DSP10 produced one order of magnitude larger power density (150 W/m 3 ) than bare graphite felt (12 W/m 3 ) in this design. These advances are some of the required modifications to enable the mini-MFC to be used in real-time, long-term environmental power generating situations.
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high power density from a miniature microbial fuel cell using shewanella oneidensis dsp10
Environmental Science & Technology, 2006Co-Authors: Bradley R Ringeisen, Ricky Ray, Brenda J Little, Emily Henderson, Jeremy J Pietron, Justin C Biffinger, Joanne JonesmeehanAbstract:A miniature microbial fuel cell (mini-MFC) is described that demonstrates high output power per device cross-section (2.0 cm2) and volume (1.2 cm3). Shewanella oneidensis DSP10 in growth medium wit...
Lewis L Lanier - One of the best experts on this subject based on the ideXlab platform.
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up on the tightrope natural killer cell activation and inhibition
Nature Immunology, 2008Co-Authors: Lewis L LanierAbstract:Natural killer (NK) cells circulate through the blood, lymphatics and tissues, on patrol for the presence of transformed or pathogen-infected cells. As almost all NK cell receptors bind to host-encoded ligands, signals are constantly being transmitted into NK cells, whether they interact with normal or abnormal cells. The sophisticated repertoire of activating and inhibitory receptors that has evolved to regulate NK cell activity ensures that NK cells protect hosts against pathogens, yet prevents deleterious NK cell-driven autoimmune responses. Here I highlight recent advances in our understanding of the structural properties and signaling pathways of the inhibitory and activating NK cell receptors, with a particular focus on the ITAM-dependent activating receptors, the NKG2D-DAP10 receptor complexes and the CD244 receptor system.
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coordinated induction by il15 of a tcr independent nkg2d signaling pathway converts ctl into lymphokine activated killer cells in celiac disease
Immunity, 2004Co-Authors: Bertrand Meresse, Veronika Groh, Lewis L Lanier, David H Raulet, Zhangguo Chen, Cezary Ciszewski, Maria Tretiakova, Govind Bhagat, Thomas Krausz, Thomas SpiesAbstract:A major function of NKG2D linking innate and adaptive immunity is to upregulate antigen-specific CTL-mediated cytotoxicity in tissues expressing stress-induced NKG2D ligands, such as MIC, by coactivating TCR signaling. Here, we show that, under conditions of dysregulated IL15 expression in vivo in patients with celiac disease and in vitro in healthy individuals, multiple steps of the NKG2D/DAP10 signaling pathway leading to ERK and JNK activation are coordinately primed to activate direct cytolytic function independent of TCR specificity in effector CD8 T cells. These findings may not only explain previous reports of transformation of CTL into NK-like "lymphokine-activated killers" (LAK cells) under high doses of IL2 (a substitute for IL15) but may also have significant implications for understanding and treating immunopathological diseases.
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nkg2d triggers cytotoxicity in mouse nk cells lacking dap12 or syk family kinases
Nature Immunology, 2003Co-Authors: Simona Zompi, Lewis L Lanier, Jessica A Hamerman, Kouetsu Ogasawara, Edina Schweighoffer, Victor L J Tybulewicz, James P Di Santo, Francesco ColucciAbstract:In activated mouse natural killer (NK) cells, the NKG2D receptor associates with two intracellular adaptors, DAP10 and DAP12, which trigger phosphatidyl inositol 3 kinase (PI3K) and Syk family protein tyrosine kinases, respectively. Here we show that cytotoxicity, but not cytokine production, is triggered by NKG2D in activated NK cells lacking either DAP12 or the Syk family members Syk and ZAP70. Inhibition of PI3K blocks this cytotoxicity, suggesting that the DAP10-PI3K pathway is sufficient to initiate NKG2D-mediated killing of target cells. Our results highlight signaling divergence in the effector functions of NKG2D and indicate that alternative associations between a receptor and its adaptors may provide a single receptor with a dual 'on-switch', giving mouse NK cells more choices through which to trigger cytotoxicity.
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impairment of nk cell function by nkg2d modulation in nod mice
Immunity, 2003Co-Authors: Kouetsu Ogasawara, Jessica A Hamerman, Honor Hsin, Shunsuke Chikuma, Helene Bourjordan, Taian Chen, Thomas Pertel, Claude Carnaud, Jeffrey A Bluestone, Lewis L LanierAbstract:Nonobese diabetic (NOD) mice, a model of insulin-dependent diabetes mellitus, have a defect in natural killer (NK) cell-mediated functions. Here we show impairment in an activating receptor, NKG2D, in NOD NK cells. While resting NK cells from C57BL/6 and NOD mice expressed equivalent levels of NKG2D, upon activation NOD NK cells but not C57BL/6 NK cells expressed NKG2D ligands, which resulted in downmodulation of the receptor. NKG2D-dependent cytotoxicity and cytokine production were decreased because of receptor modulation, accounting for the dysfunction. Modulation of NKG2D was mostly dependent on the YxxM motif of DAP10, the NKG2D-associated adaptor that activates phosphoinositide 3 kinase. These results suggest that NK cells may be desensitized by exposure to NKG2D ligands.
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an activating immunoreceptor complex formed by nkg2d and dap10
Science, 1999Co-Authors: Yaoli Song, Alexander B H Bakker, Stefan Bauer, Thomas Spies, Lewis L Lanier, Joseph H PhillipsAbstract:Many immune receptors are composed of separate ligand-binding and signal-transducing subunits. In natural killer (NK) and T cells, DAP10 was identified as a cell surface adaptor protein in an activating receptor complex with NKG2D, a receptor for the stress-inducible and tumor-associated major histocompatibility complex molecule MICA. Within the DAP10 cytoplasmic domain, an Src homology 2 (SH2) domain-binding site was capable of recruiting the p85 subunit of the phosphatidylinositol 3-kinase (PI 3-kinase), providing for NKG2D-dependent signal transduction. Thus, NKG2D-DAP10 receptor complexes may activate NK and T cell responses against MICA-bearing tumors.