Nitrate nitrogen enriched water originates from subsurface drains or "tiles" that underlay many f... more Nitrate nitrogen enriched water originates from subsurface drains or "tiles" that underlay many fields in the Corn Belt and is the primary source of NO 3 -N to surface waters in this region. To better assess the fate and transport of nutrients, such as NO 3 -N, the tile drain and pothole components of SWAT (Soil and Water Assessment Tool) were enhanced and modified in the previous component of this study. In this study, the environmental and economic impacts of various best management practice (BMP) scenarios often adopted by local farmers to reduce sediment and nutrient loadings (in particular NO 3
21st Century Watershed Technology: Improving Water Quality and Environment Conference Proceedings, 21-24 February 2010, Universidad EARTH, Costa Rica, 2010
Ali Saleh, Edward Osei, and Oscar Gallego1 1 Ali Saleh, Associate director; Edward Osei, Senior R... more Ali Saleh, Edward Osei, and Oscar Gallego1 1 Ali Saleh, Associate director; Edward Osei, Senior Research Economist, and Oscar Gallego, Assistant Research Scientist, Texas Institute for Applied Environmental Research, Tarleton State University, Stephenville, Texas. Corresponding ...
Watershed Management to Meet Water Quality Standards and TMDLS (Total Maximum Daily Load) Proceedings of the 10-14 March 2007, San Antonio, Texas, 2007
... (SWAT/APEX Program) for Upper North Bosque River Watershed in Texas Ali Saleh Texas Institute... more ... (SWAT/APEX Program) for Upper North Bosque River Watershed in Texas Ali Saleh Texas Institute for Applied Environmental Research, Tarleton State University. POBox T410. Stephenville, Texas, 76401 saleh@tiaer.tarleton.edu. Written for presentation at the ...
This study was conducted to determine if the Agricultural Policy/Environmental Extender (APEX) mo... more This study was conducted to determine if the Agricultural Policy/Environmental Extender (APEX) model could reasonably replicate the effects of silvicultural practices on streamflow and loading of sediments and nutrients. APEX was modified to enhance factors associated with forestry conditions such as rainfall interception by canopy, litter, subsurface flow, nutrient movement, and routing enrichment ratios. Historical data from the Alto watershed forestry project in east Texas were used to calibrate and test APEX. The historical data included measured flow, sediment losses, and nutrient organic N, total N, PO 4 −P, organic P, and total P) losses from nine small (2.6 to 2.7 ha) watersheds, with three replicates of each of the following treatments: (1) clearing, shearing, windrowing, and burning (SHR); (2) clearcutting, roller chopping, and burning (CHP); and (3) undisturbed control watersheds (CON). In addition, the modified APEX model was applied to two of the watersheds to demonstrate its capabilities in simulating an important sediment source (roads) and an effective best management practice (streamside management zones, or SMZs).
Proceedings of the Water Environment Federation, 2005
1Corresponding author; Research Scientist, Texas Institute for Applied Envr. Research, Tarleton S... more 1Corresponding author; Research Scientist, Texas Institute for Applied Envr. Research, Tarleton State Univ., Stephenville, TX 76402; phone: 254-968-9799; fax: 254-968-9790; email: saleh@tiaer.tarleton.edu 2 Senior Research Economist, Texas Institute for Applied Envr. ...
Total Maximum Daily Load (TMDL) Environmental Regulations II, 2003
The Maquoketa River drains 1,879 square miles of predominantly agricultural land in northeastern ... more The Maquoketa River drains 1,879 square miles of predominantly agricultural land in northeastern Iowa and is one of 13 tributaries of the Mississippi River that have been identified as contributing some of the highest levels of suspended sediments, nitrogen, and phosphorus to the ...
21st Century Watershed Technology: Improving Water Quality and Environment Conference Proceedings, 21-24 February 2010, Universidad EARTH, Costa Rica, 2010
Background: The high affinity IgE receptor (FceRI) is a crucial structure for IgE-mediated allerg... more Background: The high affinity IgE receptor (FceRI) is a crucial structure for IgE-mediated allergic reactions. We have previously demonstrated that human airway smooth muscle (ASM) cells express the tetrameric (abc2) FceRI, and its activation leads to marked transient increases in intracellular Ca 2+ concentration, release of Th-2 cytokines and eotaxin-1/ CCL11. Therefore, it was of utmost importance to delineate the factors regulating the expression of FceRI in human (ASM) cells.
Journal of the American Water Resources Association, 2002
A National Pilot Project (NPP) on Livestock and the Environment was initiated in 1992 to help pro... more A National Pilot Project (NPP) on Livestock and the Environment was initiated in 1992 to help provide solutions to environmental problems associated with livestock production. A major development of the NPP was the Comprehensive Economic and Environmental Optimization Tool-Livestock and Poultry (CEEOT-LP), an integrated modeling system designed to produce economic and environmental indicators for alternative policy scenarios applied to intensive livestock production watersheds. The system consists of a farm-level economic model (FEM) and two environmental models: the field-scale APEX model and the watershed-level SWAT model. To date, CEEOT-LP has been applied to two watersheds in Texas and one in Iowa. Predicted reductions in P losses for two P-based manure application rate scenarios, relative to baseline conditions, ranged from -4 to -54 percent across the three watersheds; however, N loss impacts ranged from a decrease of 34 percent to an increase of 79 percent. For five other alternative scenarios that were simulated for only one watershed, N and P loss impacts ranged between a reduction of 78 percent to an increase of 20 percent. Aggregate watershed-level economic impacts of the seven scenarios spanned a spectrum of a 27 percent decrease to a 25 percent increase in profit, relative to the baseline. (KEY TERMS: modeling; water quality; watershed management; nutrient management; crop rotations; tillage systems.)
Journal of the American Water Resources Association, 2008
An integrated economic and environmental modeling system was developed for evaluating agroenviron... more An integrated economic and environmental modeling system was developed for evaluating agroenvironmental policies and practices implemented on large scales. The modeling system, the Comprehensive Economic and Environmental Optimization Tool-Macro Modeling System (CEEOT-MMS), integrates the Farmlevel Economic Model (FEM) and the Agricultural Policy Environmental eXtender (APEX) model, as well as national databases and clustering and aggregation algorithms. Using micro simulations of statistically derived representative farms and subsequent aggregation of farm-level results, a wide range of agricultural best management practices can be investigated within CEEOT-MMS. In the present study, CEEOT-MMS was used to evaluate the economic and water quality impacts of nitrogen (N) and phosphorus (P) based manure application rates when implemented on all animal feeding operations in the State of Texas. Results of the study indicate that edge-of-field total P losses can be reduced by about 0.8 kg ⁄ ha ⁄ year or 14% when manure applications are calibrated to supply all of the recommended crop P requirements from manure total P sources only, when compared to manure applications at the recommended crop N agronomic rate. Corresponding economic impacts are projected to average a US$4,800 annual cost increase per farm. Results are also presented by ecological subregion, farm type, and farm size categories.
Recombinant human IL-17A, IL-1, and IL-4 were purchased from R&D Systems. Anti-phosphotyrosine S... more Recombinant human IL-17A, IL-1, and IL-4 were purchased from R&D Systems. Anti-phosphotyrosine STAT6 was purchased from BD Biosciences. Mouse mAb anti-phosphotyrosine STAT3 (Y705), affinity-purified rabbit anti-total STAT3, and STAT6 were from Santa Cruz Biotechnology. The p38 MAPK inhibitor (SB203580), the p42/p44 ERK inhibitor
Hydrologic/water quality models are increasingly used to explore management and policy alternativ... more Hydrologic/water quality models are increasingly used to explore management and policy alternatives for managing water quality and quantity from intensive silvicultural practices with best management practices (BMPs) in forested watersheds due to the limited number of and cost of conducting watershed monitoring. The Agricultural Policy/ Environmental eXtender (APEX) model was field-tested using 6 yr of data for flow, sediment, nutrient, and herbicide losses collected from nine small (2.58 to 2.74 ha) forested watersheds located in southwest Cherokee County in East Texas. Simulated annual average stream flow for each of the nine watersheds was within 6 7% of the corresponding observed values; simulated annual average sediment losses were within 6 8% of measured values for eight out of nine watersheds. Nash-Sutcliffe efficiency (EF) values ranged from 0.68 to 0.94 based on annual stream flow comparison and from 0.60 to 0.99 based on annual sediment comparison. Similar to what was observed, simulated flow, sediment, organic N, and P were significantly increased on clearcut watersheds compared with the control watersheds. APEX reasonably simulated herbicide losses, with an EF of 0.73 and R 2 of 0.74 for imazapyr, and EF of 0.65 and R 2 of 0.68 for hexazinone based on annual values. Overall, the results show that APEX was able to predict the effects of silvicultural practices with BMPs on water quantity and quality and that the model is a useful tool for simulating a variety of responses to forest conditions.
Model simulations performed representing dairies in a 93000 ha watershed in north central Texas s... more Model simulations performed representing dairies in a 93000 ha watershed in north central Texas suggest that manure incorporation results in reduced phosphorus (P) losses at relatively small to moderate cost to producers. Simulated manure incorporation with a tandem disk on fields double-cropped with sorghum/winter wheat resulted in up to 33, 45, and 37% reductions in per hectare sediment-bound, soluble, and total P losses in edge-of-field runoff, relative to simulated surface manure applications. The effects of incorporation were evaluated at three different manure application rates. On aggregate across all three manure application rates, significant declines in P losses were obtained with incorporation except for sediment-bound P losses under the N-based manure application rate scenario. We found that the practice of incorporating manure shortly after it has been broadcast on the soil surface could help reduce P losses in such situations where P-based rates alone prove inadequate. The cost the producer incurs when manure is incorporated is on average about 1% of net returns when manure is applied at the N rate and 2-3% when it is applied at alternative P-based rates. In practice the costs could be lower because producers may substitute the manure incorporation operation for a tandem disk operation performed prior to manure application. As more and more dairy producers switch to the use of sorghum and corn silage in dairy rations and consequent on-farm production of these forages, the practice of manure incorporation may help to reduce phosphorus losses resulting from dairy manure applications to fields with these forage crops.
tional complexes is described as a probabilistic process (Hume, 2000), there has been no molecula... more tional complexes is described as a probabilistic process (Hume, 2000), there has been no molecular explanation of the selective transcriptional activation of individual genes in a cluster of related receptor genes. The Ly49 family of class I major histocompatibility (the missing self hypothesis, Ljunggren and Karre, 1990). Human NK cells use the immunoglobulin-related killer cell inhibitory receptor (KIR) family of proteins to perform Summary this function while mouse NK cells use the C-type lectinrelated Ly49 proteins (Lanier et al., 1997). The Ly49 gene Murine natural killer cells selectively express members cluster has been characterized in both C57BL/6 and of the Ly49 family of class I MHC receptors; however, 129/J mice, and there are at least 14 Ly49 genes clusthe molecular mechanism controlling probabilistic tered in a head to tail array on mouse chromosome 6 expression of Ly49 proteins has not been defined. A (Wilhelm et al., 2002; Makrigiannis et al., 2002). pair of overlapping, divergent promoters discovered Each NK cell expresses a subset of the Ly49 class in the Ly49g gene functions as a molecular switch I MHC receptors, presumably to enable detection of that can produce a forward transcript containing the potential targets that have lost expression of specific coding region of the gene (on position) or a noncoding class I MHC proteins due to viral infection or malignant transcript in the opposite direction (off position), and transformation. Individual Ly49 proteins are expressed this element maintains transcription in the chosen dion a consistent percentage of NK cells in a given mouse rection. Competition of C/EBP and TBP transcription strain, and the probabilistic nature of Ly49 gene activafactors for overlapping binding sites determines the tion was suggested by the observation that the proporrelative strength of the competing promoters and the tion of NK cells expressing two Ly49 proteins is roughly probability of transcription in a given direction. Similar equivalent to the product of the proportion of NK cells elements precede all Ly49 family members, and the expressing each of the individual receptors (the product relative strength of the forward promoter in each inhibrule, Held et al., 1996). The analysis of several Ly49 itory Ly49 gene correlates with the percentage of natugenes revealed that expression is predominately monoral killer cells that express a given receptor, supporting allelic and each allele is independently chosen for stable a promoter competition model of selective gene actiexpression by a probabilistic mechanism (Held and vation. Kunz, 1998). Single-cell RT-PCR analysis of Ly49 mRNAs demonstrated that the selective expression of Introduction Ly49 proteins is controlled at the level of transcription (Kubota et al., 1999). The majority of NK cells transcribe The ability of an organism to accurately sense a complex from one to four different Ly49 genes per cell, and an environment requires the development of a complex NK cell with five or more active Ly49 genes is extremely sensory system. Selective expression of sensory receprare. Detailed analyses of the Ly49 promoters active in tors allows for the detection of complex stimuli by genermature NK/NK-T cells have demonstrated the role of ating subsets of sensory cells containing different comcis-acting elements and specific transcription factors in binations of receptors. Individual sensory cells are thus gene activation and cell-specific transcription (Held et tuned to detect specific combinations of stimuli. Recepal., 1999; Kubo et al., 1999; Gosselin et al., 2000; tors for taste and smell discrimination represent large McQueen et al., 2001; Saleh et al., 2002). gene families, and individual receptors are selectively The discovery of a novel Ly49g promoter (Pro1) upexpressed on sensory cells to allow the identification of stream of the previously studied Ly49 promoter (Pro2) complex tastes and odors (Mombaerts, 2001; Montmasuggested a possible role in the initiation of Ly49 expresyeur and Matsunami, 2002). Although monoallelic actision since Pro1 was only active in immature NK cells vation of gene expression has been described in several (Saleh et al., 2002). The current study presents a detailed systems (Hollä nder et al., 1998; Bix and Locksley, 1998; analysis of the Pro1 element, demonstrating bidirec-Held and Kunz, 1998) and the assembly of transcriptional transcriptional activity due to the presence of overlapping divergent promoters. The direction of transcription from this element was studied in vivo by linking *Correspondence: andersn@ncifcrf.gov 4 These authors contributed equally to this work. the cyan and yellow fluorescent protein genes to either Immunity 56
Philip Gassman is with the Center for Agricultural and Rural Development at Iowa State University... more Philip Gassman is with the Center for Agricultural and Rural Development at Iowa State University. Jimmy Williams and Susan Wang are with the Blackland Research and Extension Center at Texas A&M University. Ali Saleh, Edward Osei, and Larry Hauck are with the ...
A validation study has been performed using the Soil and Water Assessment Tool (SWAT) model with ... more A validation study has been performed using the Soil and Water Assessment Tool (SWAT) model with data collected for the Upper Maquoketa River Watershed (UMRW), which drains over 16,000 ha in northeast Iowa. This validation assessment builds on a ...
Nitrate nitrogen enriched water originates from subsurface drains or "tiles" that underlay many f... more Nitrate nitrogen enriched water originates from subsurface drains or "tiles" that underlay many fields in the Corn Belt and is the primary source of NO 3 -N to surface waters in this region. To better assess the fate and transport of nutrients, such as NO 3 -N, the tile drain and pothole components of SWAT (Soil and Water Assessment Tool) were enhanced and modified in the previous component of this study. In this study, the environmental and economic impacts of various best management practice (BMP) scenarios often adopted by local farmers to reduce sediment and nutrient loadings (in particular NO 3
21st Century Watershed Technology: Improving Water Quality and Environment Conference Proceedings, 21-24 February 2010, Universidad EARTH, Costa Rica, 2010
Ali Saleh, Edward Osei, and Oscar Gallego1 1 Ali Saleh, Associate director; Edward Osei, Senior R... more Ali Saleh, Edward Osei, and Oscar Gallego1 1 Ali Saleh, Associate director; Edward Osei, Senior Research Economist, and Oscar Gallego, Assistant Research Scientist, Texas Institute for Applied Environmental Research, Tarleton State University, Stephenville, Texas. Corresponding ...
Watershed Management to Meet Water Quality Standards and TMDLS (Total Maximum Daily Load) Proceedings of the 10-14 March 2007, San Antonio, Texas, 2007
... (SWAT/APEX Program) for Upper North Bosque River Watershed in Texas Ali Saleh Texas Institute... more ... (SWAT/APEX Program) for Upper North Bosque River Watershed in Texas Ali Saleh Texas Institute for Applied Environmental Research, Tarleton State University. POBox T410. Stephenville, Texas, 76401 saleh@tiaer.tarleton.edu. Written for presentation at the ...
This study was conducted to determine if the Agricultural Policy/Environmental Extender (APEX) mo... more This study was conducted to determine if the Agricultural Policy/Environmental Extender (APEX) model could reasonably replicate the effects of silvicultural practices on streamflow and loading of sediments and nutrients. APEX was modified to enhance factors associated with forestry conditions such as rainfall interception by canopy, litter, subsurface flow, nutrient movement, and routing enrichment ratios. Historical data from the Alto watershed forestry project in east Texas were used to calibrate and test APEX. The historical data included measured flow, sediment losses, and nutrient organic N, total N, PO 4 −P, organic P, and total P) losses from nine small (2.6 to 2.7 ha) watersheds, with three replicates of each of the following treatments: (1) clearing, shearing, windrowing, and burning (SHR); (2) clearcutting, roller chopping, and burning (CHP); and (3) undisturbed control watersheds (CON). In addition, the modified APEX model was applied to two of the watersheds to demonstrate its capabilities in simulating an important sediment source (roads) and an effective best management practice (streamside management zones, or SMZs).
Proceedings of the Water Environment Federation, 2005
1Corresponding author; Research Scientist, Texas Institute for Applied Envr. Research, Tarleton S... more 1Corresponding author; Research Scientist, Texas Institute for Applied Envr. Research, Tarleton State Univ., Stephenville, TX 76402; phone: 254-968-9799; fax: 254-968-9790; email: saleh@tiaer.tarleton.edu 2 Senior Research Economist, Texas Institute for Applied Envr. ...
Total Maximum Daily Load (TMDL) Environmental Regulations II, 2003
The Maquoketa River drains 1,879 square miles of predominantly agricultural land in northeastern ... more The Maquoketa River drains 1,879 square miles of predominantly agricultural land in northeastern Iowa and is one of 13 tributaries of the Mississippi River that have been identified as contributing some of the highest levels of suspended sediments, nitrogen, and phosphorus to the ...
21st Century Watershed Technology: Improving Water Quality and Environment Conference Proceedings, 21-24 February 2010, Universidad EARTH, Costa Rica, 2010
Background: The high affinity IgE receptor (FceRI) is a crucial structure for IgE-mediated allerg... more Background: The high affinity IgE receptor (FceRI) is a crucial structure for IgE-mediated allergic reactions. We have previously demonstrated that human airway smooth muscle (ASM) cells express the tetrameric (abc2) FceRI, and its activation leads to marked transient increases in intracellular Ca 2+ concentration, release of Th-2 cytokines and eotaxin-1/ CCL11. Therefore, it was of utmost importance to delineate the factors regulating the expression of FceRI in human (ASM) cells.
Journal of the American Water Resources Association, 2002
A National Pilot Project (NPP) on Livestock and the Environment was initiated in 1992 to help pro... more A National Pilot Project (NPP) on Livestock and the Environment was initiated in 1992 to help provide solutions to environmental problems associated with livestock production. A major development of the NPP was the Comprehensive Economic and Environmental Optimization Tool-Livestock and Poultry (CEEOT-LP), an integrated modeling system designed to produce economic and environmental indicators for alternative policy scenarios applied to intensive livestock production watersheds. The system consists of a farm-level economic model (FEM) and two environmental models: the field-scale APEX model and the watershed-level SWAT model. To date, CEEOT-LP has been applied to two watersheds in Texas and one in Iowa. Predicted reductions in P losses for two P-based manure application rate scenarios, relative to baseline conditions, ranged from -4 to -54 percent across the three watersheds; however, N loss impacts ranged from a decrease of 34 percent to an increase of 79 percent. For five other alternative scenarios that were simulated for only one watershed, N and P loss impacts ranged between a reduction of 78 percent to an increase of 20 percent. Aggregate watershed-level economic impacts of the seven scenarios spanned a spectrum of a 27 percent decrease to a 25 percent increase in profit, relative to the baseline. (KEY TERMS: modeling; water quality; watershed management; nutrient management; crop rotations; tillage systems.)
Journal of the American Water Resources Association, 2008
An integrated economic and environmental modeling system was developed for evaluating agroenviron... more An integrated economic and environmental modeling system was developed for evaluating agroenvironmental policies and practices implemented on large scales. The modeling system, the Comprehensive Economic and Environmental Optimization Tool-Macro Modeling System (CEEOT-MMS), integrates the Farmlevel Economic Model (FEM) and the Agricultural Policy Environmental eXtender (APEX) model, as well as national databases and clustering and aggregation algorithms. Using micro simulations of statistically derived representative farms and subsequent aggregation of farm-level results, a wide range of agricultural best management practices can be investigated within CEEOT-MMS. In the present study, CEEOT-MMS was used to evaluate the economic and water quality impacts of nitrogen (N) and phosphorus (P) based manure application rates when implemented on all animal feeding operations in the State of Texas. Results of the study indicate that edge-of-field total P losses can be reduced by about 0.8 kg ⁄ ha ⁄ year or 14% when manure applications are calibrated to supply all of the recommended crop P requirements from manure total P sources only, when compared to manure applications at the recommended crop N agronomic rate. Corresponding economic impacts are projected to average a US$4,800 annual cost increase per farm. Results are also presented by ecological subregion, farm type, and farm size categories.
Recombinant human IL-17A, IL-1, and IL-4 were purchased from R&D Systems. Anti-phosphotyrosine S... more Recombinant human IL-17A, IL-1, and IL-4 were purchased from R&D Systems. Anti-phosphotyrosine STAT6 was purchased from BD Biosciences. Mouse mAb anti-phosphotyrosine STAT3 (Y705), affinity-purified rabbit anti-total STAT3, and STAT6 were from Santa Cruz Biotechnology. The p38 MAPK inhibitor (SB203580), the p42/p44 ERK inhibitor
Hydrologic/water quality models are increasingly used to explore management and policy alternativ... more Hydrologic/water quality models are increasingly used to explore management and policy alternatives for managing water quality and quantity from intensive silvicultural practices with best management practices (BMPs) in forested watersheds due to the limited number of and cost of conducting watershed monitoring. The Agricultural Policy/ Environmental eXtender (APEX) model was field-tested using 6 yr of data for flow, sediment, nutrient, and herbicide losses collected from nine small (2.58 to 2.74 ha) forested watersheds located in southwest Cherokee County in East Texas. Simulated annual average stream flow for each of the nine watersheds was within 6 7% of the corresponding observed values; simulated annual average sediment losses were within 6 8% of measured values for eight out of nine watersheds. Nash-Sutcliffe efficiency (EF) values ranged from 0.68 to 0.94 based on annual stream flow comparison and from 0.60 to 0.99 based on annual sediment comparison. Similar to what was observed, simulated flow, sediment, organic N, and P were significantly increased on clearcut watersheds compared with the control watersheds. APEX reasonably simulated herbicide losses, with an EF of 0.73 and R 2 of 0.74 for imazapyr, and EF of 0.65 and R 2 of 0.68 for hexazinone based on annual values. Overall, the results show that APEX was able to predict the effects of silvicultural practices with BMPs on water quantity and quality and that the model is a useful tool for simulating a variety of responses to forest conditions.
Model simulations performed representing dairies in a 93000 ha watershed in north central Texas s... more Model simulations performed representing dairies in a 93000 ha watershed in north central Texas suggest that manure incorporation results in reduced phosphorus (P) losses at relatively small to moderate cost to producers. Simulated manure incorporation with a tandem disk on fields double-cropped with sorghum/winter wheat resulted in up to 33, 45, and 37% reductions in per hectare sediment-bound, soluble, and total P losses in edge-of-field runoff, relative to simulated surface manure applications. The effects of incorporation were evaluated at three different manure application rates. On aggregate across all three manure application rates, significant declines in P losses were obtained with incorporation except for sediment-bound P losses under the N-based manure application rate scenario. We found that the practice of incorporating manure shortly after it has been broadcast on the soil surface could help reduce P losses in such situations where P-based rates alone prove inadequate. The cost the producer incurs when manure is incorporated is on average about 1% of net returns when manure is applied at the N rate and 2-3% when it is applied at alternative P-based rates. In practice the costs could be lower because producers may substitute the manure incorporation operation for a tandem disk operation performed prior to manure application. As more and more dairy producers switch to the use of sorghum and corn silage in dairy rations and consequent on-farm production of these forages, the practice of manure incorporation may help to reduce phosphorus losses resulting from dairy manure applications to fields with these forage crops.
tional complexes is described as a probabilistic process (Hume, 2000), there has been no molecula... more tional complexes is described as a probabilistic process (Hume, 2000), there has been no molecular explanation of the selective transcriptional activation of individual genes in a cluster of related receptor genes. The Ly49 family of class I major histocompatibility (the missing self hypothesis, Ljunggren and Karre, 1990). Human NK cells use the immunoglobulin-related killer cell inhibitory receptor (KIR) family of proteins to perform Summary this function while mouse NK cells use the C-type lectinrelated Ly49 proteins (Lanier et al., 1997). The Ly49 gene Murine natural killer cells selectively express members cluster has been characterized in both C57BL/6 and of the Ly49 family of class I MHC receptors; however, 129/J mice, and there are at least 14 Ly49 genes clusthe molecular mechanism controlling probabilistic tered in a head to tail array on mouse chromosome 6 expression of Ly49 proteins has not been defined. A (Wilhelm et al., 2002; Makrigiannis et al., 2002). pair of overlapping, divergent promoters discovered Each NK cell expresses a subset of the Ly49 class in the Ly49g gene functions as a molecular switch I MHC receptors, presumably to enable detection of that can produce a forward transcript containing the potential targets that have lost expression of specific coding region of the gene (on position) or a noncoding class I MHC proteins due to viral infection or malignant transcript in the opposite direction (off position), and transformation. Individual Ly49 proteins are expressed this element maintains transcription in the chosen dion a consistent percentage of NK cells in a given mouse rection. Competition of C/EBP and TBP transcription strain, and the probabilistic nature of Ly49 gene activafactors for overlapping binding sites determines the tion was suggested by the observation that the proporrelative strength of the competing promoters and the tion of NK cells expressing two Ly49 proteins is roughly probability of transcription in a given direction. Similar equivalent to the product of the proportion of NK cells elements precede all Ly49 family members, and the expressing each of the individual receptors (the product relative strength of the forward promoter in each inhibrule, Held et al., 1996). The analysis of several Ly49 itory Ly49 gene correlates with the percentage of natugenes revealed that expression is predominately monoral killer cells that express a given receptor, supporting allelic and each allele is independently chosen for stable a promoter competition model of selective gene actiexpression by a probabilistic mechanism (Held and vation. Kunz, 1998). Single-cell RT-PCR analysis of Ly49 mRNAs demonstrated that the selective expression of Introduction Ly49 proteins is controlled at the level of transcription (Kubota et al., 1999). The majority of NK cells transcribe The ability of an organism to accurately sense a complex from one to four different Ly49 genes per cell, and an environment requires the development of a complex NK cell with five or more active Ly49 genes is extremely sensory system. Selective expression of sensory receprare. Detailed analyses of the Ly49 promoters active in tors allows for the detection of complex stimuli by genermature NK/NK-T cells have demonstrated the role of ating subsets of sensory cells containing different comcis-acting elements and specific transcription factors in binations of receptors. Individual sensory cells are thus gene activation and cell-specific transcription (Held et tuned to detect specific combinations of stimuli. Recepal., 1999; Kubo et al., 1999; Gosselin et al., 2000; tors for taste and smell discrimination represent large McQueen et al., 2001; Saleh et al., 2002). gene families, and individual receptors are selectively The discovery of a novel Ly49g promoter (Pro1) upexpressed on sensory cells to allow the identification of stream of the previously studied Ly49 promoter (Pro2) complex tastes and odors (Mombaerts, 2001; Montmasuggested a possible role in the initiation of Ly49 expresyeur and Matsunami, 2002). Although monoallelic actision since Pro1 was only active in immature NK cells vation of gene expression has been described in several (Saleh et al., 2002). The current study presents a detailed systems (Hollä nder et al., 1998; Bix and Locksley, 1998; analysis of the Pro1 element, demonstrating bidirec-Held and Kunz, 1998) and the assembly of transcriptional transcriptional activity due to the presence of overlapping divergent promoters. The direction of transcription from this element was studied in vivo by linking *Correspondence: andersn@ncifcrf.gov 4 These authors contributed equally to this work. the cyan and yellow fluorescent protein genes to either Immunity 56
Philip Gassman is with the Center for Agricultural and Rural Development at Iowa State University... more Philip Gassman is with the Center for Agricultural and Rural Development at Iowa State University. Jimmy Williams and Susan Wang are with the Blackland Research and Extension Center at Texas A&M University. Ali Saleh, Edward Osei, and Larry Hauck are with the ...
A validation study has been performed using the Soil and Water Assessment Tool (SWAT) model with ... more A validation study has been performed using the Soil and Water Assessment Tool (SWAT) model with data collected for the Upper Maquoketa River Watershed (UMRW), which drains over 16,000 ha in northeast Iowa. This validation assessment builds on a ...
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